8-4-2010.pdf 6-4-2010.pdf 10-4-2010.pdf microsoft word كريم نجم 4 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 finite element analysis of deep drawing and springback kareem najm hussien abstract the paper studies the distribution of stresses and strains of deep drawing process until the failure. the process is modeled with its four basic parts: the punch, the die, the holder and the blank. as the study concentrates on the blank, the blank in modeled as an elastic body, where the other parts are modeled as rigid bodies .the study is performed on two sets: the first set with von-mises plastic criteria & the second set with hill criteria to take the anisotropy into consideration. for both set the coefficient of friction is set to constant value. the study focuses on the failure analysis by changing the punch stroke until the value of the blank diameter to monitor the thinning of the cup thickness. due to importance of the springback in metal forming which determines the residual stress inside the blank, model of springback is added. the study is performed using the finite element code ansys 11 .the effect of entropy; stroke length and springback on the deep drawing process can be no test on the behavior on the metal forming. keywords: finite element, deep drawing, spring-back, ansys. طريقة العناصر المحدودة في تحليل السحب العميق وظاهرة المرونة الراجعة حسين نجم كريم زــــــــــــــــــــــــوجالم الفشل حالة حدوث حتى و العميق السحب عملية إثناء االنفعاالت و االجهادات توزيع دراسة إلى البحث يهدف الدراسة إن حيث و .الصفيحة و والماسك األنثى والقالب الذكر القالب: األربعة اجتزائها في العملية تم تمثيل. مراعاة مع صلدة بأجزاء المتبقية األجزاء و مرنة كمادة الصفيحة مثلت الصفيحة في دحالق تكوين على تركز المرونة معيار باستخدام األولى: مجموعتين على الدراسة أجريت . األربعة األجزاء بين التماس ظروف في للتغير يجةنت الميكانيكية الخواص في التغير ألخذ ذلك و هل مرونة معيار باستخدام األخرى و ميسيس-فون طول يكون حتى الشوط طول بتغيير ذلك و الفشل حدوث حالة على الدراسة ركزت. االعتبار بنظر االتجاه .للفشل معيارا الصفيحة سمك في الترقيق يعتبر حيث المتولد القدح قطر لطول مساويا الشوط حركة انتهاء بعد المترسبة هاداتاالج مقدار تحدد التي و المعادن تشكيل في المرونة رجوع حالة وألهمية العناصر طريقة على يعتمد الذي 11 االنسيس برنامج على الدراسة أجريت . المحاكاة هذه إضافة تم الحمل .المحددة introduction deep drawing is the metalworking process used for shaping flat sheets into cup-shaped articles such as bathtubs, shell cases, and automobile panels. this is done by placing a blank of appropriate size over a shaped die and pressing the metal into the die with a punch (figure19). generally a clamping or hold-down pressure is required to press the blank against the die to prevent wrinkling. kareem najm hussien  this is best done by means of a blank holder or hold-down ring in a double-action press. although the factors which control the deep-drawing process are quite evident, they interact in such a complex way that precise mathematical description of the process is not possible in simple terms. the greatest amount of experimental and analytical work has been done on the deep drawing of a flat-bottom cylindrical cup (swift test) from a flat circular blank. the discussion of deep drawing which follows will be limited to this relatively simple situation. the spring-back is referred to an event when the sheet metal starts vibrating after the punch is removed and might alter its final desired shape. since it takes some time before the work-piece comes to a rest, almost all papers depend on the finite element methods as a numerical tool for simulating the deep drawing process. a good general treatment of this method is given by (s. s. rao, 2004) but application of this method to metal forming processes is given by (shiro, 1989) the degree of the application of the finite element depends on the nonlinearities (a. ayari, et al 2009). the uses of the ductile material may the magnesium (t. s. yang, 2008) or aluminum at elevated temperature to predict the final geometry of the blank (g. venkateswarlu, et al2010). the influence of material parameters such as hardening exponent, yield stress and elastic modulus on the process are investigates (gao en-zhi, et al, 2009). the investigation of the geometrical tolerances between the punch and the blank or between the blank and the die is studied (waleed, 2007). since the process involves many parameters, minimization of response time and maximization of the efficiency and quality is studied as well (hakim s. sultan aljibori, 2009). theoritical background deep drawing is the metalworking process used for shaping flat sheets into cup-shaped articles (dieter 1988). it is done by placing a blank over a shaped die and pressing the metal into die by a punch. a holder is required to press the blank against the die to prevent wrinkling. the process has complicity to be modeled directly. the four parts of the process are shown in figure 1. the stress and deformation in a draw cup is show in figure 2. the draw ability of a metal is measured by the ratio of the initial blank diameter do to the cup diameter drawn from the blank dp. for a given material there is a limiting draw ratio (ldr), representing the largest blank that can be drawn through a die without tearing. in our study the efficiency for frictional losses is η = 0.7 and ldr=2. this means it is a difficult to draw a cup with a height greater than its diameter. model description the geometry, the material properties and the applied load is needed in our analysis. the geometry of the assembly is shown in the figure 1. the finite element model is shown in the rest figures. a fine mesh of elements type (plane182) is generated on blank geometry (100 mm of diameter and 2 mm of thickness). this element has four nodes of two degree of freedom, two translations and one rotation. the punch, the holder and the die are assumed to be solid bodies. the gap between the punch and die is set equal to the initial thickness of blank sheet. the material properties of the blank sheet are: modulus of elasticity 200 gpa tangent modulus 1 gaps yield stress 250 mpa poisson ratio 0.3 the load is applied as a prescribed displacement representing the punch stroke with holder force 5 kn. the friction between the parts was set as a coulomb friction of 0.1 coefficients. two sets of calculation were performed. the first set with no anisotropy while the second set has anisotropy according to hill as 10% (ansys manual, 2007). appendix a al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 138 finite element analysis of deep drawing and springback failure criteria two types of failures were followed through the modeling. the depth of the cup created should not exceed the diameter of the blank sheet (dieter, 1988) and the thinning should be kept bellow 20% of the original thickness (t. altan, 2000). results and discussion figure 3 shows the affective von-mises stress for both sets of calculation, while figure 4 shows the effective elastic strain. figures 5 to 9 show the distribution of effective von-mises stresses for the first set of calculation for different stroke of punch, while figures 10 to14 show the results of the second set. the von-mises stress after spring-back for stroke of 60 mm is shown in figure 15. for this stoke the von-mises strain is shown in figure 16. from the figure, the punch is in its original position after spring-back. taking the anisotropy into consideration, figure 17 shows the von-mises stress for 60 mm stroke and figure 18 shows the von-mises strain. by zooming the graphical results, the thinning of the wall is evident. it is clear that figure 9 for the first set of calculation is under failure mode which corresponds to stroke of 90 mm; figure 13 for the second set of calculation corresponds to 80 mm punch stroke. conclusions the obtained results of simulation present a visual approach to predict the failure shape of the process according to the thinning of the thickness of the formed cup. the spring back is another visual approach to the accuracy of the modeling. by this approach a parametric design could be done and an optimized selection of parameters could be achieved. references achievement in materials and manufacturing process, 2008 ansys 11 “help manual”, 2007 f. ayari, t. lazghab and e. bayraktar, “ parametric finite element analysis of square cup deep drawing”, computational materials science and surface engineering, 2009 gao en-zhi, li hong-wei, kou hong-chao, chang hui, li jin-shan and zhou lian, “influences of material parameters on deep drawing of thin-walled hemispheric surface part”, nonferrous met. soc. china 19, 2009 george e. dieter, “mechanical metallurgy”, 3rd edition, mcgraw-hill company, 1988 g. venkateswarlu, m. j. davidson and g. r. n. tagore ,"finite element simulation of deep drawing of aluminum alloy sheets at elevated temperatures”, arpn journal of engineering and applied sciences, 2010 hakim s. sultan aljibori, abdel magid hamouda. "finite element analysis of sheet metal forming process “, european journal of scientific research, 2009 s.s. rao, “the finite element method in engineering”, pergamon press, oxford, 4th edition, 2004. shiro kobayashi, soo-ik oh and taylan altan, ”metal forming and the finite element method”, oxford university press, 1989. t. altan, “forming improving progressive die design by simulation”, stamping journal. 2000. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 139 kareem najm hussien  t. s. yang “finite element analysis of elliptic cup deep drawing of magnesium alloy sheet”, journal of waleed khalid jawad, "investigation of contact interface between the punch and blank in deep drawing process”, eng. & technology, vol.25, no.3, 2007 figure 1 the four parts of deep drawing process figure 2 the stain and stress distribution inside the cup al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 140 finite element analysis of deep drawing and springback figure 3 the equivalent von-mises stress against the length of punch strok figure 4 the equivalent von-mises strain against the length of punch stroke al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 141 kareem najm hussien  figure 5 the von-mises stress for 50 mm stroke figure 6 the von-mises stress for 60 mm stroke al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 142 finite element analysis of deep drawing and springback figure 7 the von-mises stress for 70 mm stroke figure 8 the von-mises stress for 80 mm stroke al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 143 kareem najm hussien  figure 9 the von-mises stress for 90 mm stroke figure 10 the von-mises stress for 50 mm stroke with anisotropy al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 144 finite element analysis of deep drawing and springback figure 11 the von-mises stress for 60 mm stroke with anisotropy figure 12 the von-mises stress for 70 mm stroke with anisotropy al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 145 kareem najm hussien  figure 13 the von-mises stress for 80 mm stroke with anisotropy figure 14 the von-mises stress for 90 mm stroke with anisotropy al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 146 finite element analysis of deep drawing and springback figure 15 von-mises stress for 60 mm stroke after springback figure 16 von-mises strain for 60 mm stroke after springback al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 147 kareem najm hussien  figure 17 von-mises stress for 60 mm stroke after springback with anisotropy figure 18 von-mises strain for 60 mm stroke after springback with anisotropy al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 148 finite element analysis of deep drawing and springback figure 19 model for the springback procedure appendix a springback in ansys as it is well known in the forming analysis, the springback phenomena should be taken into the consideration. a procedure in ansys concerning this type of deep drawing analysis which has a prescribed displacement has the following steps: 1 solve the problem with displacement load as usual 2 find the reaction force at the pilot node 3 delete the displacement load and add the force load from 2 4 solve the problem one iteration only 5 apply zero force at pilot node 6 solve the problem as usual non-linear case all the procedure is done inside the solution phase. hill's table for material number 1 0 temperature 1.1 rxx 1.1 ryy 1.1 rzz 1.1 rxy 1.1 ryz 1.1 rxz al-qadisiya journal for engineering sciences, vol. 5, no. 2, 137-149, year 2012 149 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 172 improvement of temperture resistance of al-mg/al2o3p composite by coating with antimony trioxide film mushtaq taleb albdiry al-qadisiya university mechanical department saad hameed alshafaie babylon university materials department abstract aluminum matrix composites amcs with 10 wt % al2o3 particles with average size (3.86 µm) were fabricated by stir casting method, then the composite produced coated with antimony trioxide (sb2o3) by hot dipping coating process. thermal conductivity of composite materials with and without coating was estimated by applying fourier equation to investigate its behavior under different temperature conditions. results revealed that coating with antimony trioxide decreased the thermal conductivity (k) of composite material. the thermal conductivity of the master composite material was (207 w/m°c) at (80 °c) and (182 w/m°c) of the coated composite material at same temperature. keywords: aluminum matrix composite, antimony trioxide, thermal conductivity, temperature resistance. (al-mg/al2o3p) آبةارتللمواد الم مقاومة درجة الحرارة تحسين بطالئها بطبقة من اوآسيد االنتيمون الثالثي سعد حميد الشافعي آلية الهندسة-جامعة بابل هندسة المواد ق طالب البديريمشتا آلية الهندسة-جامعة القادسية الهندسة الميكانيكية صةالخال (% wt 10)بنسبة (al2o3) ات اوآسيد األلمنيوم ئ من جزي amcs ذات أساس األلمنيوم المعدنية آبة ارتصنعت المواد الم آبة الناتجة باوآسيد ارمتالمادة ال بعدها تم طالء ,stir casting) (السباآة بالمزج باعتماد طريقة (µm 3.86)ومتوسط حجم حبيبي (thermal conductivity, k) ارية رحسبت الموصلية الح ,(hot dipping) التغطيس الحار عتماد طريقة با االنتيمون الثالثي آبة حيث ارتفأظهرت النتائج بان طبقة الطالء باوآسيد االنتيمون تعمل على تقليل الموصلية الحرارية للمادة الم ,رباعتماد معادلة فوري آبة ارتالم بينما قيمتها للمادة (c°80)عند درجة حرارة w/m˚c (207 (آبة األساس هي المتراللمادة الموصلية الحرارية قيمة آانت .عند نفس الدرجة الحرارية (w/m˚c 182 ) هي المطلية al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 173 introduction high-performance thermal materials, which are at various stages of development, fall into five main categories: monolithic carbonaceous materials, metal matrix composites (mmcs), carbon/carbon composites (cccs), ceramic matrix composites (cmcs) and polymer matrix composites (pmcs) (3 ،8 ،10). a metal matrix composite (mmcs) is a material with at least two constituent parts, one being a metal, the other material may be a different metal or another material, such as a ceramic or organic compound. when at least three materials are present, it is called a hybrid composite. mmcs are made by dispersing a reinforcing material into a metal matrix, the matrix is the monolithic material into which the reinforcement is embedded, and is completely continuous. this means that there is a path through the matrix to any point in the material, the matrix is usually a lighter metal (low density metals, and lower coefficient of thermal expansion), such as aluminum, magnesium, or titanium, and provides a compliant support for the reinforcement. the reinforcement material is embedded into the matrix, used to change materials properties such as wear resistance, friction coefficient, or thermal conductivity (surappa, 2003). one of the common methods of manufacturing of mmc materials is stir casting; discontinuous reinforcement is stirred into molten metal, which is allowed to solidify (liquid state methods) (surappa, 2003). dip coating techniques can be described as a process where the substrate to be coated is immersed in a liquid and then withdrawn with a well-defined withdrawal speed under controlled temperature and atmospheric conditions. the coating thickness is mainly defined by the withdrawal speed, the solid content and the viscosity of the liquid. if the withdrawal speed is chosen such that the sheer rates keep the system in the newtonian regime, the thickness of coating depend on thickness of the piece, and temperature of the piece at the moment of dipping, the coating thickness slightly varied from 150 µm to 400 µm(schmidt, 2000). the interesting part of dip coating processes is that by choosing an appropriate viscosity. the schematics of a dip coating process are shown in figure 1. the famous application of antimony trioxide is a flame retardant for wide range of plastics, rubbers, papers, and textiles (alexander, 2007، heinrich,2000), it is white, granule structure, high efficiency, less toxicity and environmental clean, also it is consider odorless white crystalline powders, stable under ordinary conditions, and slightly stable in water (www.antimony-cn.com.). table (1) shows some of the properties of antimony trioxide (from the product). al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 174 heinrich, h. and stefan, p.(heinrich,2000) tried to improve the thermal properties of frp composite by using a sodium silicate and vermicular film coating as a flame retardant materials., but ali (ali, 2003) studied the effects of adding (10, 20, 30 wt %) of a flame retardant materials (antimony trioxide) on thermal properties (thermal conductivity, heat capacity, and flame resistance) of glass fiber reinforced polyester composite materials and he concluded the thermal conductivity results were (1.41 w/m.˚c),and (1.136 w/m.°c) at (55°c) for with and without (30% sb2o3) addition respectively. despite the availability of some studies(2،5 ،6 ،7 ) for improving the thermal properties of composite materials, but all of these studies were applied on polymer matrix composites, while the present study aims to study the effect of the coating film of sb2o3 on some of thermo physical properties of aluminum metal matrix composite as a trial to improve it’s ability to withstand various temperature to be suitable for using in application of automotive engine parts. experimental details: 1. preparation of the composite materials: the initial metal alloy (al-3mg) was prepared by melt a (500g) of aluminum foils (purity 99.99%) with a (3wt% of magnesium) according to center of vortex and mixing for (3-5 min) by (heidolph mixer type/germany) with speed 420 rpm, after the initial alloy was prepared directly it dispersed (by stir casting route) with aluminum oxide particles (al2o3) with average particle size (3.86 µm) and (10 wt%) at mushy state (eutectic point) at 645°c, and then it cast into cylinder ingots of (25 mm diameter and 30 mm in length) at mild steel molds. 2. preparation of the testing specimens: in this study a film of antimony trioxide (sb2o3) would coated on surface of aluminum matrix composite by hot dip process under certain conditions of temperature for the sake of improving the thermal properties of composites, cylindrical specimens whose dimensions were (25 mm in diameter and 30 mm in length) were obtained to be as a sample for coating process, these samples were clean out, polished, and immersed by (20%hcl solution) for five minutes (it’s weight 37.0008 grams),and then it heated for 300 °c (by careful control of thermal balance external heating of the molten metal may even be eliminated), and finally it immersed directly in the hot antimony molten bath (750 °c) for a minute, and it has been leaving inside the oven even it cool down and oxidation process was done. after three or four stages preparative treatment, some slight film would remain after oxidation (with weight 37.8014 grams); the thickness of (sb2o3) film was measured using the difference between densities, as shown in equation (1) below (george, 2002): ρ = m /v ……………………………………………………………… (1) ρ: density of the part (g/mm3). al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 175 m: mass of the cylinder (g) v: volume of the part (mm3). 3. thermo physical testing: some of the thermo physical properties (density, thermal conductivity, and thermal resistivity) of aluminum matrix composite before and after coating with antimony trioxide film were measured to investigate the effect of coating on thermal properties of (amcs): density of mmcs material can be determined by simple using the relationship between volume and mass or by (archimedean density), the equation (1) above. thermal conductivity can be measured by comparative method with steady state longitudinal heat flow in a temperature, the comparative instrument measures that flow based upon the known thermal properties of standard reference materials, thermal conductivity test specimen is sandwiched between two identical reference samples; this stack is placed between two heating elements controlled at different temperature. figure 2 shows the thermal conductivity measurement device. thermal conductivity coefficient (k) can be calculated from the expression below (fourier low) (george,2002): k= l t a q ∆ . . . …………………………………………. …………….. (2) k: thermal conductivity coefficient (w/m.°c). q: heating power of the heater (kw). ∆t/l: temperature gradient across the stack measured by thermocouple. l: length of the specimen (cm). ∆t: temperature difference between heater and heat sink (°c). a: cross section area of the specimen (cm2). thermal resistivity coefficient (1/k) of mmcs measures during taking the thermal conductivity reverse. results and discussion: an antimony trioxide film with a thickness (313 µm) was coated on aluminum matrix composite (amcs) by using hot dip coating process to improve the thermal behavior, some of thermo physical properties (density, thermal conductivity, and thermal resistivity) of (al-mg/10al2o3) were measured ,the density of (al-mg/10al2o3) was (2.5125 g/cm3), and the density of antimony powder was (6.684 g/cm3), while the density of composite material with coating by antimony trioxide was (2.5403g/cm3). figures 3 and 4 show the relationship between various temperature (80-110°c), and values of thermal conductivity (k) of amcs before and after coating by sb2o3 film, the thermal conductivity of the master composite material would increase when values of temperature are increased, where the conductivity of amcs was ( 207 w/m.°c) at (80 °c) and it became (234 w/m.°c) at 110 °c, while the al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 176 effective of sb2o3 coating was decreased the thermal conductivity of composite to (182 w/m.°c) and to (228 w/m.°c) at 80 °c and 110°c respectively, because the antimony trioxide (as a flame retardant) does as a trapping of the entire temperature. figures 5 and 6 show the relationship between the temperature and thermal resistivity (1/k); we can see the decreasing of the thermal resistivity of amcs with increasing of the temperature, and also the effective of sb2o3 film was decreased the heat transmission. conclusion: the results of coated of (amcs / al-mg/al2o3) by an antimony trioxide (sb2o3) as a flame retardant material revealed, the coated film was improved the temperature resistance and reduced the thermal conductivity of (amcs). references: 1. alexander, b. m. and charlis, a. w.;” flame retardant polymer nano composites” (book preface), published by john wiley & sons inc. (2007). 2. ali i. m.; “studying the using of antimony trioxide as a flame retardant”, m.sc thesis, babylon university, materials engineering (2003). 3. fleming, t.f.; levan, c.d.; and riley, w.c. “applications for ultra-high thermal conductivity fibers,” proceedings of the 1995 international electronic packaging conference, international electronic packaging society 1995, pp. 493-503. 4. george, k.; erich, n.; “thermo physical properties of metal matrix composites:” mmc-assess thematic network, vol.7, 2002 australlian research center, georg.korb@arcs.ac.at. or erick.neubauer@arcs.ac.at 5. heinrich, h. and stefan, p.;” the importance of intumescences systems for fire protection of plastic materials”, polymer international 49, 2000. 6. jeng maw. c. and chung d.l.; “improvement of the temperature resistance of aluminum-matrix composites using an acid phosphate binder”, journal of materials science 28(1993)1471-1687. 7. pickard, s.m. and et al,”high thermal conductivity metal matrix composites”, us patent (www.freepatentsonline.com/7279023.html.). 8. rao, vv; murthy, k. mv and nagaraju, j.; “thermal conductivity and thermal contact conductance studies on metal matrix composite”. composites science and technology 64(16):2004 pp. 2459-2462. 9. schmidt, h. and mennig, m.; “ wet coating technology for glass”, inm conference,germany (2000). 10. surappa, m.k.,” aluminum matrix composites: challenges and opportunities”, sadhana vol 28, part 1 & 2 february/april 2003, p. (319-334). 11. (www.antimony-cn.com.), private company website: shenyang hua chang antimony chemical co. ltd, china alexander, b. m. and charlis, a. w.;” flame retardant polymer nano composites” (book preface), published by john wiley & sons inc. (2007). al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 177 table (1): some properties of antimony trioxide ([www.antimony-cn.com) formula molecular weight melting temperature boiling temperature specific gravity sb2o3 (sb4o6) 291.52 652 ˚c 1570 ˚c 5.2 g/mm3 fig.(1) :stages of the dip coating process: dipping of the substrate into the coating solution, wet layer formation by withdrawing the substrate and gelation of the layer by solvent evaporation (schmidt,2000) fig 2: thermal conductivity measurement device al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 178 70 80 90 100 110 120 temperature, c 180 200 220 240 t he rm al c on du ct iv ity w /m . c composite material without coated composite material coated by sb2o3 layer fig. (3): the relationship between the temperature and thermal conductivity (k) of amcs with and without coating by sb2o3 fig. (4): the relationship between the temperature and thermal conductivity (k) of amcs with and without coating by sb2o3 0 50 100 150 200 250 thermal conductivity (w/m.c) 80 90 100 110 temperture (c) co mpo site m aterials witho ut co ating co mpo site m aterials co ating by sb2o3 , ° c w/m.° c al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 179 70 80 90 100 110 120 temperature , c 4.0 4.5 5.0 5.5 6.0 t he rm al r es is tiv ity m . c /w * 0. 00 1 composite materials without coating composite materials coated by sb2o3 layer fig. (5): the relationship between the temperature and thermal resistivity (1/k) of amcs with and without coating by sb2o3 0 1 2 3 4 5 6 thermal resistivity (m.c/w) 80 90 100 110 temperature (c) composite material coating by sb2o3 composite material without coating , ° c m.° c /w fig. (6): the relationship between the temperature and thermal resistivity (1/k) of amcs with and without coating by sb2o3 9-2-2011.pdf 101 the structure is a very important aspect in neural network design, it is not only impossible to determine an optimal structure for a given problem, it is even impossible to prove that a given structure is optimal. in this paper, pso (particle swarm optimization) are used to construct best ann (artificial neural network) architectures, and find an optimal pattern of connections and weights to reduce structure complexity by minimizing the number of connection weights in a feed forward artificial neural network (ffann). they are called particle swarm optimization-neural network systems (psonn). psonn systems are examined through theoretical analysis and computer simulation using matlab package. they are tested by several different examples, where the tests show that pso a more efficient and automated search method can be used to find an optimal topology of ann. the best and trained network with few numbers of iteration is provided using psonn for finding an optimal structure. finally, a simpler network, faster training with higher accuracy than full connected network is obtained by using psonn for finding optimal connections and weights. artificial neural networks, particle swarm optimization, pattern recognition. )pso ( ).ffann ()psonn(االوزان ل تم . matlab . pso pso. particle swarm optimization (pso) is a relatively new evolutionary algorithm that may be used to find optimal (or near optimal) solutions to numerical and qualitative problems. particle swarm optimization was originally developed by a social psychologist (james kennedy) and an 102 electrical engineer (russell eberhart) in 1995 [ ], and emerged from earlier experiments with algorithms that modeled the flocking behavior seen in many species of birds. although there were a number of such algorithms getting quite a bit of attention at the time, kennedy and eberhart became particularly interested in the models developed by biologist frank heppner [ ]. heppner studied birds in flocking behaviors mainly attracted to a roosting area. in simulations, birds would begin by flying around with no particular destination and spontaneously formed flocks until one of the birds flew over the roosting area. due to the simple rules the birds used to set their directions and velocities, a bird pulling away from the flock in order to land at the roost would result in nearby birds moving towards the roost. once these birds discovered the roost, they would land there, pulling more birds towards it, and so on until the entire flock had landed. finding a roost is analogous to finding a solution in a field of possible solutions in a solution space. the manner in which a bird who has found the roost, leads its neighbors to move towards it, increases the chances that they will also find it. eberhart and kennedy revised heppner’s methodology so that particles could fly over a solution space and land on the best solution simulating the birds’ behavior [ ]. neural network is an artificial intelligence model originally designed to replicate the human brain’s learning process. a typical network is composed of a series of interconnected nodes and the corresponding weights. it aims at simulating the complex mapping between the input and output. the training process is carried out on a set of data including input and output parameters. the learning procedure is based on the training samples and the testing samples are used to verify the performance of the trained network. during the training, the weights in the network are adjusted iteratively till a desired error is obtained [ ]. this capability of learning from data without a prior knowledge makes neural networks particularly suitable for classification and regression tasks in practical situations. the most popular supervised learning technique in ann is back-propagation bp algorithm. the back-propagation algorithm involves the gradual reduction of the error between model output and the target output. it develops the input to output, by minimizing a mean square error cost function measured over a set of training examples. the problem with neural networks is that a number of parameters have to be set before any training can begin. however, there are no clear rules as to how to set these parameters. yet these parameters determine the success of the training. therefore, pso is used to find their optimum values [ ]. a particle represents the weight vector of nn, including all biases. the dimension of the search space is therefore the total number of weights and biases. the fitness function is the mean squared error (mse) over the training set. changing the position means updating the weight of the network in order to reduce the error. all the particles update their position by calculating the new velocity, which they use to move each particle to the new position. the new position is a set of new weights used to obtain the new error. for pso, the new weights are adapted even though no improvement is observed. this process is repeated for all the particles. the particle with the lowest error is considered as the global best particle so far. the training process continues until satisfactory error is achieved by the best particle or computational limits are exceeded. when the training ends, the weights are used to calculate the classification error for the training patterns. the same set of weights is used then to test the network using the test patterns [8, 9]. in this paper the ability of particle swarm optimization pso in designing artificial neural networks (ann) is discussed. the multi-layer perceptron (mlp) is taken into account as an ann structure to be optimized [ ]. in particle swarm optimization, the particles are “flown” through the problem space by following the current optimum particles. each particle keeps track of its coordinates in the problem space which are associated with the best solution (fitness) that it has achieved so far. this implies that each particle has a memory, which allows it to remember the best position on the feasible search space that it has ever visited. this value is commonly called . another best value that is 103 tracked by the particle swarm optimizer is the best value obtained so far by any particle in the neighborhood particle. this location is commonly called [ ]. the particles learn over time in response to their own experience and the experience of the other particles in their group. each particle keeps track of its best fitness position in hyperspace that has achieved so far. this value is called personal best or pbest. the overall best value obtained by so far by any particle in the population is called global best or gbest . during each epoch (or iteration) every particle is accelerated towards its own personal best as well as in the direction of the global best position. this is achieved by calculating a new velocity term for each particle based on the distance from its personal best, as well as its distance from the global best position. these two components (‘personal’ and ‘global’ velocities) are then randomly weighted to produce the new velocity value for this particle, which will in turn affect the next position of the particle during the next epoch. shows the basic pso procedure. pso is basically developed through simulation of bird flocking in two-dimension space. the position of agent is represented by xy-axis position and also the velocity is expressed by vx (the velocity of x-axis) and vy (the velocity of y-axis). modification of agent position is realized by position and velocity information. pso is a population-based stochastic optimization technique modeled on the social behaviors in animals or insects, bird flocking, fish schooling and animal herding. pso initially has population of random solutions each potential solution called particle, is flown through the problem space, the particles have memory and each particle keeps track of previous best position and corresponding fitness. the previous best value is called as ‘pbest’ it also has an other value called ‘gbest’ which is the best value of all the particles pbest in the swarm. the basic concept of pso technique lies in accelerating each particle toward its pbest and the gbest locations at each time step. the main equations in pso described as below: ))()(())()(()()1( 2211 (1) ( 11 (2) where are random numbers in the range [0, 1], 1 and 2 are positive constants, 1 and 2 represents the rate of the position change (velocity) for particle , represent the ith particle, and is the inertial weight. the pso algorithm is simple in concept easy to implement and computational efficient. the original procedure for implementing pso is as follows: 1. initialize the swarm in solution space 0 , is random position within the solution space and the velocity = 00 2. evaluate fitness of individual particles. fitness of . 3. modify gbest, pbest and velocity. if then and if tixf > gbest then and update velocity according to equation (1). 4. move each particle to a new position according to equation (2). 5. repeat until convergence or a stopping condition is met or maximum number of iteration. figure (1) shows the basic procedure of pso algorithm[ ] 104 pso is a computational intelligence based technique that is not largely affected by the size and nonlinearity of the problem, and can converge to the optimal solution in many problems where most analytical methods fail to converge. it can therefore, be effectively applied to different optimization problems. it’s an optimization algorithm that using only primitive mathematic calculation. so the advantage of the pso over many of the other optimization algorithms is its ability to handle optimization problems with multiple local optima reasonably well and relative simplicity of implementation the calculation speeds and fast. moreover, pso has advantages over other similar optimization techniques, namely the following: 1) pso is easier to implement and there are fewer parameters to adjust. 2) in pso, every particle remembers its own previous best value as well as the neighborhood best; therefore, it has a more effective memory capability than other optimization technique. 3) pso is more efficient in maintaining the diversity of the swarm (more similar to ideal social interaction in a community), since all the particles use the information related to the most successful particle in order to improve themselves there are not many parameter need to be turned in pso. here is a list of the parameters and their typical values the number of particles, the typical range is about 10 to 40. actually for most of the problems 10 particles is large enough to get good results. for some difficult or special problems, one can try 100 or 200 particles as well. dimension of particles, it is determined by the problem to be optimized. range of particles, it is also determined by the problem to be optimized, we can specify different ranges for different dimension of particles. learning factors, c1 and c2 usually equal to 2. the stop condition, the maximum number of iterations the pso execute and the minimum error requirement [ ]. this algorithm is tested with matlab package:four patterns of 3x3 pixels are shown in . in this test a neural net of (9) input neurons (they are equal to the length of input vector), (4) hidden neurons and (4) output neurons (they are equal to the number of patterns used in training set). the parameters of pso are adjusted to bring the network out of its local minima. so c1=c2=2, r1=0.4, r2=0.9, and =0.2 2 =0.2 and =0.2, the inertial weight decrease from 0.9 to 0.2 linearly. the initial weights randomly generated between [-12,12] and biases between [8,8] with maximum velocity [vmax=18]. the mean square error (mse=10e-7) against the maximum number of iterations (epoch=1500) are shown in and illustrate the accuracy performance of the pso. : ten patterns of 7x7 pixels are shown in . a neural network of (49) input neurons, (10) hidden neurons and (10) output neurons is used in this test). before training process, the parameters of training algorithm (pso) set to swarm size=25 particles, c1=c2=2, r1=0.8 and 2 and r2=0.2, the inertial weight decrease from o.9 to 0.2 linearly. the initial weights randomly generated between [-10, 10] and biases between [9, 9] with maximum velocity [vmax=20].the maximum number of iterations (epoch) =1500 and mean square error (mse=10e-7). it can be seen that, the best network for each test can be obtained in a small number of iteration (generation) with low number of epoch for training with pso. show the curves of the mse against the number of iterations of the training the optimal network. illustrate the accuracy performance of the pso. 105 4. psonn for optimal connections and weights optimization is used to refer to reducing structural complexity by minimizing the number of weights in a feed forward artificial neural network (ffann). such optimization offers advantages in terms of simpler networks, faster training and better generalization ability to avoid over fitting due to over sized network. optimization of ffann structure includes the selection of appropriate inputs and outputs, and the determination of the number of connections between each neuron inside the network. in other words, the goal is to have a network with a low connectivity, both for speed of operation, and for a better ability to generalize. the goodness of an individual is determined by two parameters: the mse and the total possible connections. the mse can be scaled by the ratio of the actual connections ( ) to total possible connections ( ) [ ]. the fitness function which can be used in pso is: (3) it can be seen that equation3 is the best one to achieve good effect on the algorithm to get optimal connections and weights and reaches the lower value of mse than the fully connected neural network with a very few number of iteration. show the neural networks for the two tests (a) and (b) respectively with optimum connections obtained from equation3. the merits of pso algorithm can be summarized as follows: firstly, with parallel search strategy, it can locate the global optimization consistently. secondly, its velocity – displacement search model is simple and easy to implement. thirdly, few parameters should be considered and set up. moreover, the information flow with single direction can absolutely speed up the convergence process. finally, variable inertial weight can effectively guarantee the compromise between global search and local search. by using psonn for designing an optimal neural network, the optimal structure, including number of hidden layers, number of hidden neurons, is found. at the end of the process not only the best network structure for a particular application but also the trained network with little number of epochs is provided. psonn for finding optimum connections and weights uses pso to reduce structural complexity by minimizing the number of connection weights in a ffann. tests show that by this algorithm, a simplex network, faster training with higher accuracy than the old network (full connected network) is obtained. the equation (3) used to find the optimal pattern of connections and weights by scaling the mse by the ratio of the actual connections ( ) to total possible connections ( ), therefore pso is an optimization algorithm reduces the connections of ann by 30%. it directs the search through the intelligence generated from cooperation and competition among the individuals. . a. p. engelbrecht, “ computational intelligence: an introduction”, john wiley & sons ltd, 2007. . c. blum, d. merkle,” “springer-verlag berlin heidelberg, 2008. g. k. venayaga moorthy and r. g. harley, “swarm intelligence for transmission system 106 control”, ieee1-4241298-6, 2007. j.kennedy and r.c eberhart,” ” san francisco: morgan kaufmann publishers, . . k. chandramouli and e.izquierdo, “image classification using chaotic particle swarm optimization”, ieee 142440481, icip2006. l. wang, x. wang, j. fu and l. zhen, “anovel probability binary partical swarm optimization algorithm and its application”, journal of software, vol. 3, no.9, 2008. m. clerc, “ ” iste ltd, 2006. t. su, j. jhang and c.hou,” ”, international journal of innovative computing, information and control, volume 4, number 9, september, 2008. . r. mendes, p. cortez, m. rocha and j. nevers,” ”, ieee, june, 2002. . y. shi, “ ”, ieee neural network society, february, 2004. 107 gbest pbest next particle basic pso procedures [shi 2004]. 108 -1 -1 1 1 -1 1 -1 1 -1 -1 1 1 1 1 -1 -1 p = 1 1 1 -1 1 1 -1 -1 -1 -1 1 1 -1 1 -1 1 -1 -1 1 1 . . training mse with iterations for optimum network for test (a). the test: a-the patterns, b-the patterns’ matrix. 109 the test patterns: (a) the patterns, (b) the patterns’ matrix. accuracy performance pso (a) after 5 iterations (b) after 1500 iterations (a) (b) 110 accuracy performance of pso aafter 5 iterations b after 1500 iterations 111 the proposed ann for test with the optimal connections by using pso. the proposed network for test with the optimal connections by using pso. 4-2-2011.pdf 37 in this research a parabolic solar concentrator system has been experimentally studied. the experimental devise consists of a communication satellite dish with 1.5 m diameter and 0.17 m depth. its interior surface is covered with aluminum reflecting layer and equipped with a disc receiver, (with diameter of 0.22 m and depth of 0.07 m) in its focal position. the orientation of the dish is assured by the tracking system for the satellite, as a tracking system for the sun, with some limitations. performance of the solar evaporating system is tested under the local conditions of najaf city during the interval from 10/3 to 25/4/2010. the data are collected on ambient temperature, temperature of inflow water, water and vapor temperatures inside the receiver. the obtained results showed that the amount of distillate was much dependent on the incident solar radiation intensity and the accurate focusing of the system. the system productivity can range from 6.9 to 15.3 l/day of fresh water, when the air was used to condensate the vapor receiver output (air – cooling), and this productivity increased by 28 – 33.5% when the inflow water used to condensate the vapor receiver output (water – cooling). / / . ١,٥٠,١٧. . ) ٠,٢٢٠,٠٧(على شکل . ) ل( ، . ١٠/٣٢٥/٤/٢٠١٠ل . ، للمستقبل 38 . ،)(مستقبل/٦,٩١٥,٣ ٣٣,٥-٢٨ %).( symbol definition units a,b constant parameters depend on the month d opening diameter of a paraboloid m f focal length m h depth of the parabolic solar concentrator m id incident solar radiation on inclined surface w/m2 idn direct normal solar radiation s surface area of a paraboloid m2 so opening surface area of a paraboloid m2 sr solar radiation mj/m2.day tair ambient (air) temperature oc tvd vapor temperature inside the receiver oc twd water temperature inside the receiver oc twin inflow (receiver input) water temperature oc greek symbol definition units β altitude angle of the sun deg. θ incident angle of the solar radiation deg. ∑ tilt surface angle deg. one of the possible solutions for availability of potable water, which become a burning problem in rural areas, could be desalination of saline water. desalination of saline water has been practiced regularly for over 55 years and is well established means of water supply in many countries. however, the purpose of using desalination process is to produce fresh water at reasonable cost. most of the desalination processes are based on expensive fuels like electricity, coal, gas, etc. thus, to provide fresh water at reasonable cost, it is urgent to convert fuel operated technology to solar operated technology ( ). the sun is an outstanding energy source for mankind. it is clean and comes to the earth for free. there is no need to drill and refine it or mine it out of the ground. the devices needed to gather its energy are simple, quiet and non-polluting ( ). two forms of solar energy are distinguished, direct radiation and diffused radiation. solar high temperature designs require concentration systems, such as parabolic reflectors. in general solar concentrating systems comprise a reflective surface in the shape of paraboloid of revolution 39 intended to concentrate solar energy on an absorbing surface, which makes it possible to reach a high temperature ( ). this process gives the possibility to use solar energy in many high temperature applications. but the manufacture of the most of these systems is very expensive due to materials quality, dimensions and precision. so that, many authors worked to reduce the cost of this kind of systems ( ). some experimental studies have been carried out to investigate the performance, the productivity of the solar concentrator and the suitable sun tracking system, which will further improve the efficiency of the evaporator. , have investigated the performance of a concentrator assisted still and a flat-plate collector assisted still. they conclude that the efficiency of the system utilizing the concentrator was higher than the collector assisted system. , have done an experiment on a parabolic solar reflector alongwith a suitable heat-mechanism for desalination of saline groundwater. to enhance the output of the system, two flat collectors were put in series. the developed evaporating system was capable of producing 1215 liter/day of potable water. , have investigated the performance of a parabolic concentrator coupled with solar still. the parabolic concentrator was coupled with still in such a way that the solar radiations were made to focus at the base of the tray of the still. the maximum amount of distillate was 2.2 l on august 4, 2002 and minimum amount of distillate 0.37 l on august 16, 2002. , presented an experimental study for the effect of using two-axis sun tracking system on the thermal performance of compound parabolic concentrators (cpc). it was reported that tracking cpc collector showed a better performance with an increase in the collected energy of up to 75% compared with an identical fixed collector. a parallel experimental study presented by el ouederni1 et al., 2008, for a parabolic solar concentrator devise, which consists of a dish of 2.2 m opening diameter. its interior surface is covered with a reflecting layer and equipped with a disc receiver in its focal position. the orientation of the parabola is assured by two semi-automatic jacks. the obtained results describe correctly the awaited physical phenomena. the review of the above research efforts emphasizes the need to increase the output of solar based distillation approaches. the low efficiency is still a major concern for solar operated evaporators ( ). therefore, study was carried to develop and test solar concentrator for desalination of water and to investigate the productivity of the solar concentrator with and without water – cooling, which also called the preheating method, for different focal lengths. the components of the proposed solar concentrator system ) include: parabolic solar reflector, sun tracking mechanism, receiver (heat absorber), water supply system and preheating system. the details of these components are given as below: the reflector was used in this work consists of a parabolic concentrator of 1.5 m opening diameter and 0.17 m depth. its interior surface is covered with a reflecting layer (aluminum foil with 0.5 mm thickness), which reflects solar rays on the face of a receiver placed at the focal position of the concentrator. a variable length holder was fixed at the centre of the reflector to hold the receiver (heat absorber) within the focal length of solar reflector. the surface of a paraboloid of opening diameter (d) whose focal distance (f) is giving by ( ): 40 3 2 2 2 f4 d 1f 3 π8 s (1) the surface of opening of a paraboloid is: 4 dπ s 4 o (2) the focal distance is given by the following expression: h16 d f 2 (3) where, h: is the depth of the parabolic solar concentrator. thus, the characteristics of the parabolic solar concentrator of this experimental device are given in . electric motor with remote control commonly used for satellite tracking was purchased from the market and used to rotate the reflector for east-west rotation with one degree for each five minutes to ensure the reflected rays continuously in the focal zone. one end of the motor was attached to the base which joined to the backside of the reflector, while the other end was fixed to the main holder of the system. the motor was attached to an electronic tracking unit that constructed locally. for north-south rotation the reflector moving manually every six days toward the sun declination, after specified it for that day, to insure the correct focal point. the reflector focusing was a very laborious job. in order to avoid the laborious job of focusing the system repeatedly as well as to improve the efficiency of the evaporator, there was a need to develop a fully automatic tracking system, which is underway by using solar sensors ( ). the receiver is a stainless steel disc with a diameter of 0.22 m and depth of 0.07 m. it is located in the focal zone of the parabola. all sides of the receiver are insulated, to reduce the heat dissipated to the surrounding, except the side which placed to face the reflected rays is covered with a thin coat of black paint to decrease the reflexion of the solar rays. for water inlet and steam outlet, two valves are welded on the top of the receiver to controlling the water amount from the water supply system with the evaporation rate inside the receiver. a stainless steel pipe (0.05 m length and 0.003 m diameter) welded at the base of the receiver and curved towards the top. this pipe extended by pyrex pipe (0.20 m length and 0.003 m diameter) as a sight glass for the water level inside the receiver and addition to this, it is used to remove the concentrated salts, which accumulated at the bottom of receiver during the evaporation process of raw water. the accumulated salts are usually removed at the end of day. during the operation of the solar system the receiver (heat absorber) reaches the maximum level at 1.98 m from the ground. in order to supply water to heat absorber, an overhead water tank 41 was placed on a 2.5 m high stand. the water flow rate to the heat absorber was controlled by gate valve welded to the top of it. thus, pressure head and water flowing from the overhead water tank to heat absorber was controlled. the water flow rate to the heat absorber was also maintained according to the rate of evaporation inside it. an aluminum pipe of 0.01 m diameter and 0.78 m length was covered with a water jacket, a galvanized iron pipe of 0.025 m diameter and 0.7 m length. the jacket was designed to receive water inflow from the water tank and deliver to the heat absorber. in this way, water jacket served two purposes: condensing the vapor from the absorber as well as to harvest vapor heat to further warm the water flowing to the heat absorber. thermocouples were distributed along the solar system, calibrated with standard thermometer between 0 oc and 110 oc, to measure the ambient air temperatures, the temperatures of water and vapor inside the receiver, the inflow water temperatures. all experiments are achieved during the months of march and april of 2010 in najaf, iraq (latitude angle 32.2on), and the solar radiation estimated during this interval of time depending on the equations which giving by ( ): θcosii dnd (4) where: βsin b expaidn (5) sinβcoscosβsincosθ -1 (6) β and are shown in two manners are used to achieved experiments; one with using the ambient air to condensate the vapor deliver the heat absorber (air – cooling) to produce the fresh water and the other with using the preheating unit (water – cooling) to condensate this vapor for increasing the fresh water productivity. for each test the position of the receiver was varied, depending on the dish diameter (d), to reaches the best focal point. thus, four values for the focal length were selected (0.5d, 0.55d, 0.6d and 0.65d). the distilled water is accumulated in plastic container and measured by scaled flask every hour. daily accumulated of fresh water ranging from 6.9 to 15.3 l/day. the raw water in the overhead tank, with salinity of 1790 ppm, is poured into the heat absorber through the gate valve to fill it with knowing level. the reflected rays from the reflector surface on the face of the heat absorber will heats the water inside it to evaporate and escape from the other gate valves to passes either through aluminum pipe with 0.158 m length and 0.006 m diameter to condensate depending on the ambient air temperature or through the preheating unit to condensate depending on the inflow water temperature. eventually, the condensate was accumulated in the plastic container to measured hourly by the scaled flask. 42 the temperature of the ambient (tair), inflow water (twin), water and vapor inside the receiver (twd and tvd respectively) and the solar radiation (sr) versus time for different focal lengths (0.5d, 0.55d, 0.6d and 0.65d), for the two manners of condensation, are shown in . it can be seen from these figures that the same trends of the temperature behavior for all focal lengths, where the temperature rises during the measuring time up the maximum value at 14:00 hr and then trend to decrease. it is noticed that the solar system operates at high temperature when the heat absorber fixed at a focal length equal to 0.55d, because the most reflected rays from the reflector surface was focused on the heat absorber (receiver) face. show the dependence of the production rate (distillated) on the focal length and the manner of product vapor condensation, addition to the main two factors: the ambient temperature and the solar radiation. generally, it is found that the production rate increase with increasing the solar intensity to reaches the maximum value at 14:00 hr, after that the decrease in temperature gradually reduce the production rate. the greater amount of the distilled water is obtained when the focal length was 0.55d and the preheating unit was used as vapor condensation manner (water – cooling). the findings in the present study indicated that: 1. the parabolic solar concentrator can be used successfully for desalination of water to provide potable water for domestic usage. 2. the parabolic solar concentrator operates with temperatures higher than that of the different types of the solar stills. 3. the best focal length of the parabolic solar concentrator is equal to 0.55 of the dish diameter (d). 4. the amount of the potable water was much dependent on the accurate focusing of the system and increased by 28 – 33.5% when the preheating method was used. 1. ahmad r. n., sial j. k. and arshad m., "development and performance evaluation of solar saline-water evaporator", pakistan journal of water resources, vol. 9 (2005) 4148. 2. el ouederni1 a.r., dahmani a.w., askri f., ben salah m. and ben nasrallah s., "experimental study of a parabolic solar concentrator" revue des energies renouvelables cicme’08 sousse (2008) 193 – 199. 3. garg h. p and prakash j., "solar energy, fundamentals and applications", tata mcgraw-hill publishing company limited, 2007. 4. kalogirou s. a., "solar thermal collectors and applications", progress in energy and combustion science 30 (2004) 231-295 5. kalogirou s., eleflheriou p., lloyd s. and ward j., "low cost high accuracy parabolic troughs construction and evaluation", renewable energy, vol. 5(1994) pp. 384 386. 6. khalifa abdul-jabar n. and al-mutawalli s.s., "effect of two axis sun tracking on the performance of compound parabolic concentrators", energy conversion and management vol. 39, (1998) 1073-1079. 7. li m., wang r.z., luo h.l., wang l.l. and huang h.b. "experiments of a solar flat plate hybrid system with heating and cooling", applied thermal engineering 22 (2002) 1445–1454. 43 8. palavras i. and bakos g.c., "development of a low-cost dish solar concentrator and its application in zeolite desorption", renewable energy, vol. 31(2006) 2422 – 2431. 9. qiblawey h. m. and banat f., "solar thermal desalination technologies" desalination 220 (2008) 633-644. 10. singh s. k., bhatnagar p. and tiwari g. n., "design parameters for concentrator assisted solar distillation system ", energy conversion and management vol. 37, no. 2, (1998) 247252. 11. zulqurnan m., "designing, fabrication and performance study of a conical solar still coupled with the parabolic concentrator", m.sc thesis, department of physics, university of agriculture, faisalabad (2002). characteristics of the solar concentrator diameter of opening of the parabola 1.5 m total surface of the parabola 1.86 m2 surface collecting of the parabola 1.76 m2 depth of the parabola 0.17 m focal length 0.827 m 44 experimental device planning of experimental main parts device β ∑ 45 hourly variation of temperatures for the solar system with air cooling and focal length of 0.5d. : hourly variation of temperatures for the solar system with water cooling and focal length of 0.5d. 46 : hourly variation of temperatures for the solar system with air cooling and focal length of 0.55d. : hourly variation of temperatures for the solar system with water cooling and focal length of 0.55d. 47 : hourly variation of temperatures for the solar system with air cooling and focal length of 0.6d. : hourly variation of temperatures for the solar system with water cooling and focal length of 0.6d. 48 : hourly variation of temperatures for the solar system with air cooling and focal length of 0.65d. : hourly variation of temperatures for the solar system with water cooling and focal length of 0.65d. 49 : hourly variation of the solar system productivity for focal length of 0.5d. : hourly variation of the solar system productivity for focal length of 0.55d. 50 : hourly variation of the solar system productivity for focal length of 0.6d. : hourly variation of the solar system productivity for focal length of 0.65d. ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٩ دراسة تأثیر التلوث على ظاھرة الومضة العابرة لعوازل خطوط شبكة الجنوب الغربي (132kv)العراقیة وارد صايل وارد مصدق رشيد شنور وريوس هندسة كهربائيةماجستير هندسة كهربائية بكال الشطرة/ المعهد التقني/ الشطرة مدرب فني /المعهد التقني / مدرس مساعد الخالصة تصنف ظاهرة الومضة العابرة كأحدى اهم المشاكل التي تعاني منها العوازل المستخدمة في انظمة النقل المـسببات الرئيـسية لهـذه يعد التلوث احد اهـم . المستخدمة اجئ للمنظومة والتي تتسبب بخروج مف والتوزيع، .الظاهرة وعند الفولتية التشغيلية للنظام ) kv 132(تم في هذا البحث دراسة تأثير التلوث على اداء الومضة العابرة لعوازل خطـوط الـضغط العـالي المواقع ذات الظروف البيئية القاسية والتي ربعة من انتخبت ا ،لغربي المارة بالمناطق الصحرواية لشبكة الجنوب ا .تعرضت عوازلها للتلوث ليتم بعدها فحص قيم فولتيات االنهيار في مختبر الضغط العالي يكشف البحث عن وجود تغيرات ذات معنى فى االداء الكهربائي للعوازل نتيجة الظروف الصحراوية والمتمثلـة فـي قيمـة فولتيـة " لقد اظهرت النتائج انخفاضا خطيـرا والرطوبة العالية، ودرجة الحرارة بالعواصف الرملية . كما قورنت النتائج مع العوازل الغير ملوثة" االنهيار كلما ازداد العازل تلوثا .الضغط العالي، الومضة العابرة، العوازل، التلوث، العواصف الرملية: كلمات رئيسية a study of pollution effect on flashover phenomena for south-west iraqi (132kv) grid insulators warid sayel warid musadak rasheed sanwar technical institute shatra technical institute shatra ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٠ abstract the flashover phenomena constitutes as one of the important high voltage insulators problems which may cause costly outage for power system. pollution is the most essential element in this phenomena at system working voltage. in this paper, a research program is executed to investigate the pollution effect on flashover phenomena for south – west iraqi (132kv) grid insulators routing through desert areas . in order to carryout the investigation, four typical sites have been selected, for each site one insulators string that suffering from deposition of contaminated substances has been select and brought to high voltage laboratory for checking flashover voltage values. from the present work it can be concluded that to a large extent, insulators show a significant changes in the electrical performance as exposed to desert environmental conditions like high temperature, humidity and sandstorms . a significant reduction in flashover voltage is observed as the pollution amount increases, these results have been compared with the new insulators. قائمة الرموز iec 507 : وثيقة الفحص القياسي للجمعية الكهروتقنية الدولية dsl : طريقة الطبقة الملحية الجافة )dry salt layer method( ddg : العداد االتجاهي لكثافة الترسب الرمليطريقة) directional dust deposit density( nsdd : الغير ذائب طريقة كثافة الترسب الملحي)non-slouble salt deposit density( esdd : طريقة كثافة مكافئ الترسب الملحي)equivalent salt deposit density ( المقدمة كنتيجة للتطور والنمو السريع لمتطلبات الحمل تم ادخال العديد من انظمة القدرة الكهربائية الى الخدمة وبفولتيات الحاجة بمرور خطوط الضغط العـالي عبـر المنـاطق ، لقد قضت ]ahmet and suleiman. ,1990[متنوعة ومرورها بالقرب من المناطق الساحلية لوجـود بسبب توافر عامل االمان واالدخار، الغير مأهولة مثل الصحراء ] .٦،١[التجمعات السكانية او المناطق الصناعية بسبب المتطلبات التشغيلية تستخدم عوازل الضغط العالي لفصل مستويات متعددة من الفولتية وبسبب طبيعة بناء خطـوط النقـل الهوائيـة ترسب المواد الملوثة، درجـة ( رات اهمها والمحطات الثانوية المكشوفة تتعرض هذه العوازل غالبا الى عدة مؤث ر الزمن يترسب التلوث على سطح العـازل ، ومع مرو ] ٧،٦،١) [العواصف الرملية ، الرطوبة ،الحرارة العالية ، )الضباب، الرطوبـة، االمطـار ( البيئية والمناخية مثل تحت تأثير هذه الظروف ) electrolyte(وتتشكل طبقة .وفي بعض الحاالت وعندما يكون تصميم العازل غير مناسب وكفوء تنتهي المسألة بحدوث الومضة العابرة ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢١ نظمة القدرة الكهربائية وهذه الحالة تقلـل مـن وثوقيـة عابرة في العديد من ا الومضة ال حاالتلقد تكرر حدوث .الستردادوتتسبب بخسائر مادية غير قابلة لالشبكة ع فيها العازل في البيئـة تعتمد الية الومضة العابرة او احتمالية حدوثها على نوع التلوث والفترة الزمنية التي وض لغـرض ى شـدته قق من العوامل التي تسبب التلوث لسطح العازل وقياس مد لذا اصبح من المهم التح ،الملوثة التصميم الصحيح لعزل الخطوط الهوائية والمحطات الثانوية باالضافة الى اختيار نوع العزل والبرنامج المناسب ].seyyed and ahmed ,2004[لصيانة العازل قياسـية حـول اليـة ويـة بيانات دقيقة تحـت ظـروف فيزيا برزت الحاجة في االونة االخيرة لطريقة تعطي ونظرا الهمية المسألة اجريت العديد من البحوث والدراسات حول عالقة التلوث مع ظـاهرة الومـضة التلوث، .بمدى شدة التلوث على سطح العازلالعابرة ، لتأتي النتائج باثبات قوة ارتباط هذه الظاهرة للتلـوث ) longrod( من نـوع تعريض سلسلة العوازل]ahmet and suleiman. ,1990[ استخدم الباحثون الطبيعي وبفترات زمنية مختلفة كوسيلة الجراء الفحوصات لبيان مدى شدة التلوث وتأثيره على فعالية الومـضة ـ فقـد berlijn and engelbrech (2001)) (لبـاحثون اامـا ، العـابرة فحـص الجهـد المتزايـد وادخل )progressive stress test ( باالشتراك مع طريقة الطبقة الملحية الجافة)dsl ( لمقارنة اداء التلوث لعـوازل florian and[نـاقش البـاحثون مضة العابرة تحت ظروف تلوث معينـة، مختلفة واحتساب امكانية حدوث الو josef ( 2005) [ نتائج قياس زاوية التوصيل)contact angle ( لعينات من المواد العازلـة ولعـدة اسـماك ) .artificial pollution(مختلفة من التلوث المصطنع sprial shaped(تم بحث اداء العوازل ذات الحلقات الحلزونية الشكل الملوثـة ] krystian (2003)[الباحث sheds ( ،حيث اظهرت النتائج انخفاض قيمة فولتية االنهيار لهذا النوع من العوازل مقارنة مـع وفي عدة بلدان طريقة فحـص mats and ralf (2003) قترح الباحثون ا.)standard sheds(العوازل ذات الحلقات القياسية وتم مقارنة نتـائج الفحـص مـع الفحـص القياسـي ) dsl(تلوث جديدة سميت بطريقة الطبقة الملحية الجافة )iec507) (salt-fog test (ة للساحل ولعـدة واظهرت الطريقة الجديدة مالئمتها للتطبيق في الظروف المناخي . انواع من العوازل لمحاكاة العاصـفة الرمليـة المحملـة ) موديل(نموذج ] mohamed and hassan, 2002[كما طور الباحثون أثيرهـا علـى بذرات الرمل المشحونة بفولتيات متناوبة مرة وبفولتيات مستمرة مرة اخرى ومن ثم معرفة مدى ت .خصائص الومضة العابرة ddg ,nsdd(عدة طرق لقياس شدة التلوث بضمنها ] seyyed and ahmed (2004)[لباحثان ااستعرض ,esdd (ارنتها مع طريقة ومن ثم مق )leakage current measurement. ( ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٢ ]٧[مراحل تشكل الومضة العابرة للعازل الملوث .المادة الملوثة على سطح العازل ) settling( ترسب -١ مع مياه االمطار ومن ثم تكون الطبقة ) soluble pollutants( اختالط المادة الملوثة القابلة للذوبان -٢ .)conductive layer(الموصلة . بداية تكون التيار التسربي في العازل-٣ . ارتفاع درجة حرارة سطح العازل-٤ . جفاف سطح العازل -٥ .ومن ثم الومضة العابرة ) partial discharge( حدوث التفريغات الجزيئية -٦ انواع التلوث لـوث تـالف فيبين عازل م )٢(الشكل رقم اما تلوث الذي تتعرض له اسطح العوازل، شدة ال )١(الشكل رقم يبين -: ]٧،٦،١[يمكن تصنيف التلوث الذي يصيب سطح العازل الى ثالثة انواعبسبب الومضة العابرة، -) :saline pollution(التلوث البحري -أ العاليـة المناطق الساحلية حيت تتواجد الكثير من التجمعات السكانية ويتميز المناخ هنـاك بالرطوبـة تتصف به .وانتشارالبخار المحمل باالمالح -) :industrial pollution( التلوث الصناعي ب .ن احتمالية حدوث الحاالت الطارئةينتشر في المواقع الصناعية بهيئة غازات وابخرة مما يرفع م -) :desert pollution( التلوث الصحراوي -ج عند العواصف الرمليـة يغطـى الـسطح الخـارجي للعـازل بـذرات ف ، باالتربة المتراكمة على العوازل يتمثل ،زاء من االمارات العربية المتحـدة اج البحرين،العراق، (لقد عانت الكثير من بلدان الشرق االوسط مثل ، الرمل البحر الميت في االردن فتعاني بشكل نسبي من منطقة امامن التلوث الصحراوي، ) شمال افريقيا، مصر، سوريا ،ك خليط من انواع التلوث المذكورة هنا وقد يكون ، المحملة بنسبة عالية من االمالح مكون من ذرات الرمل تلوث يوجد خليط من التلوث البحري والصحراوي الذي احدث العديـد ) باكستان(فعلى سبيل المثال في منطقة كراتشي .من حاالت الومضة العابرة بشكل متكرر ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٣ البيانات المستخدمة الجـدول حيث يبين، )400kv ,132kv(تتألف شبكة الجنوب الغربي من مجموعة خطوط ضغط فائق وبفولتية يركـز المأخوذ من دائرة شبكات الجنوب الغربي اسماء الخطوط والجهد المسلط وعدد االبراج والدوائر، )١(رقم cap( ابعاد العوازل من نـوع )٣(الشكل رقم حيث يبين 132kv)(مستخدمة في خطوط البحث على العوازل ال and pin. ( flash(تتعرض اغلب هذه الخطوط لعواصف رملية موسمية مما يرفع من احتمالية حدوث الومـضة العـابرة over ( رارة العاليـة وارتفـاع باالضافة الى الظروف البيئية القاسية المتمثلة في الكثير من االحيان بدرجات الح المستخدم فـي احـدى ) longrod( عازل ملوث من نوع )٤(الشكل رقم معدالت الرطوبة النسبية حيث يظهر ).longrod( عازل تالف من نوع )٥(الشكل كما يظهر ،)kv 132(خطوط النتائج والمناقشة ر عرضة للعواصف الرمليـة وهـي والتي تكون اكث ) kv 132(لغرض اجراء البحث تم انتخاب اربع خطوط -شـمال الـسماوة (،)الـسماوة –الناصرية ( ،)المصب العام –الناصرية القديمة ( ،)رميلة الجديدة -المصب العام ( للمعلومات المأخوذة من دائرة شبكات الجنوب الغربي، حيث تتم عمليـة الـصيانة الدوريـة " وهذا طبقا ) الرميثة عمليات الصيانة لوحظ ان تلك الخطوط كانت االكثر تلوثا وهـي فـي ومن خالل استمرار ) kv 132(لخطوط نفس الوقت االكثر تسجيال لحاالت الومضة العابرة، كما تؤكد ايضا المعلومات المأخوذة من الهيئة العامة لالنـواء لرمليـة الجوية والرصد الزلزالي ان المناطق التي تمر فيها هذه الخطوط االربعة هي االكثر تعرضا للعواصف ا من كل خط منتخب عنـد )cap and pin(مقارنة مع بقية الخطوط، لقد تم فتح سلسلة من العوازل الملوثة نوع . ١٩٦٧اجراء احدى عمليات الصيانة وبنفس العمر التشغيلي لهذه الخطوط والتي اسست عام rising( الفولتيـة او فحـص رفـع ) progressive stress test(تم استخدام تقنية فحص الجهـد المتزايـد voltage test ( الحتساب قيمة فولتية االنهيار))ة تأثير التلوث على عـوازل للعازل ومقارن)) الومضة العابرة بأسـلوب ) object(يتم في هذا النوع من الفحوصات رفع قيمـة الفولتيـة المـسلطة علـى العـازل ،مختلفة يرتكز هذا الفحص علـى جراء حساب احصائي للنتائج،التي يمكن من خاللها ا) step-wise fashion(الخطوة .) عددالخطوات قمة الخطوة، فترة الخطوة، فولتية البدء،( عدة متغيرات وهي ابتدأ ،رفع الفولتية المسلطة على العازل حيث نبدأ بالجزء االبتدائي المتمثل ب يتألف الفحص المستخدم من جزئين، وصوال للفولتية االعتياديـة المـسلطة ) step duration(معينة زمنية عدد من الخطوات ذات فترة من الصفر وب step(اما في الجزء الرئيسي يتم زيادة الفترة الزمنية للخطوة وتقليـل قمـة الخطـوة ،)kv 76(على العازل ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٤ amplitude) ((لتمكين التسخين بالتيـار التـسربي ) مقدار الزيادة في الفولتيةleakage current ( وظـاهرة .)dry band arc phenomena(مة القوس الجاف حز دائي للفحص المؤلف في الجزء االبت ) kv 15(مع قمة خطوة ) دقائق 3( هذا البحث فترة خطوة اعتمدنا في الـذي يتوقـع فيـه حـدوث في الجزء الرئيسي ) kv 7(وقمة خطوة ) دقائق 8(وفترة خطوة ، ) دقيقة 20(من ).دقيقة80 (المؤلف منو الومضة العابرة المـستخدم فـي خطـوط ) cap and pin(تم اجراء فحص الجهد المتزايد علـى عـازل جديـد مـن نـوع )132kv( الشكل رقم حيث يبين)وبـدون حـدوث ظـاهرة عالقة الزمن مع الفولتية المسلطة على العازل )٦ )الرميثـة –ماوة شـمال الـس ( لخـط )132kv( فيبـين اداء عـازل )٧(الـشكل رقـم امـا ،الومضة العابرة هـي المفحـوص للعـازل يث يظهر الشكل ان فولتيـة الومـضة العـابرة والمعرض مسبقا للتلوث الطبيعي ح ) kv 139 ( الـشكل رقــم مـن الفولتيـة التــي يمكـن ان يتحملهـا العـازل، امـا وهـي اقـل بكثيـر)٨( مــــن خــــطمــــأخوذ) kv 132( لعــــازل الــــسابقة فيبــــين نفــــس العالقــــة وهي اسواء من الحالة السابقة بـسبب ) kv 118 (حيث كانت قيمة فولتية الومضة العابرة ) سماوة -الناصرية ( ، امـا ) رميثة –شمال السماوة ( اكثر بكثير من خط ) السماوة -الناصرية( كون التلوث الحاصل في عوازل خط يمـة فولتيـة الومـضة حيث كانـت ق ) المصب العام –الناصرية القديمة (( فيبين النتيجة لخط ) ٩(الشكل رقم وهـــــي اقـــــل نـــــسبيا مـــــن الحالـــــة الـــــسابقة، )kv 111(العـــــابرة والذي يبدو اكثر العوازل تلوثا والموضح اداءه في ) رميلة الجديدة _ المصب العام ( العازل المفحوص لخط اما .)kv 97( لتنخفض الى ا خطيرا بقيمة فولتية الومضة العابرة اظهر انخفاض)١٠(الشكل لجميع العوازل المفحوصة للخطوط االربعة المنتخبـة حيـث قيم فولتيات الومضة العابرة )١١(كل رقم الشيبين . كلما ازداد العازل تلوثا بين لدينا انخفاض فولتية الومضة العابرةيت االستنتاجات وهذا يقلل من وثوقيـة للعوازل الملوثة مقارنة مع العازل الغير ملوثلوحظ انخفاض قيمة فولتية الومضة العابرة كما لـوحظ ايـضا ان صا عند العواصف الرملية الشديدة، الشبكة ويرفع احتمالية حدوث االعطال المفاجئة خصو انخفاضـا فـي قيمـة تلوثا واكثرها)kv 132(هو اكثر خطوط ) الرميلة الجديدة–المصب العام ( عوازل خط . بين كمية التلوث وفولتية االنهيار مما يثبت صحة العالقة مافولتية الومضة العابرة يوصي البحث بزيادة عدد مرات التنظيف الدوري للعوازل العاملة ضمن المناطق االكثـر عرضـة للعواصـف .الرملية واستخدام الدهان الهيدروكربوني لطالء اسطحها ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٥ المصادر [1] ahmet r. and suleiman m. '' pollution flashover performance of high voltage insulators a round jeddah region'', journal of islamic academy of sciences, vol.3, no.1, pp. 1-5.1990 [2] berlijn s. and engelbrech c. '' use of progressive stress in dsltests to compare the pollution performance of insulators'', nordic insulation symposium, stockholm, 11-13 june, pp. 183-190.2001 [3] florian f. and josef k. ''contact angle measurement on insulators surfaces with artifical pollution layers and various surface roughnesses'', proceeding of the xivth international symposium on high voltage engineering, tsinghua university, china, 25-29 august, pp. 47-51-2005 [4] krystian c. '' pollution behaviour of insulators with sprial shaped sheds'', interfaces in electrical insulation systems, vol. 8, no. 8, pp. 97-102-2003 [5] mats h. and ralf h.'' the dry salt layer (dsl) method a new pollution test method for coastal environment'' , ieee transaction on power delivery, vol. 18, n0. 3, pp. 953-959, 2003 [6] mohamed m. and hassan m.'' effect of sandstorm with charged particles on the flashover and breakdown of transmission lines'', cigre, paris, france, vol. 9, no. 2, pp. 306311, 2002 [7] seyyed m. and ahmed g.'' evalution of leakage current measurement for site pollution severity assessment'', leonardo electronic journal of practices and technologies, vol 10, pp. 39-54,2004. ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٦ نوب الغربيالجيبين بيانات خطوط شبكات ) ١(جدولال الجهد اسم الخط ت kv طول الخط km عدد الدوائر عدد االبراج ١ ٤١٦ ٢٠٥ ٤٠٠ ور الزبير خ–ناصرية ١ ١ ٣٧٨ ١٧٦٫٦ ٤٠٠ قادسية –ناصرية ٢ ١ ٤١٥ ١٩٩٫٤ ٤٠٠ واسط –ناصرية ٣ ١ ١٤٨ ٤٦ ١٣٢ ١/ شطرة –ناصرية ٤ ٢ ١٥٢ ٤٦ ١٣٢ ٢/ شطرة –ناصرية ٥ ١ ١٠٠ ٣٤ ١٣٢ رفاعي –شطرة ٦ ١ ٤٠٠ ١٢٩ ١٣٢ دجيلة –رفاعي ٧ ١ ١٢٨ ٣٩ ١٣٢ جنوب الكوت –دجيلة ٨ ١ ٢٩٩ ٩٦ ١٣٢ سماوة –ناصرية ٩ ٢ ١٢٧ ٣٤ ١٣٢ ساوة –سماوة ١٠ ١ ٢٧١ ٨٥٫٥ ١٣٢ قادسية –شمال السماوة ١١ ١ ٨٨ ٣٠٫٥ ١٣٢ رميثة --شمال السماوة ١٢ ١ ١٨٥ ٥٥ ١٣٢ قادسية –رميثة ١٣ ١ ٣٠٨ ٩٦٫٨ ١٣٢ شامية–شمال السماوة ١٤ ٢ ٤٥ ١٣٫١٤ ١٣٢ شمال الناصريه–ناصرية ١٥ رميلة – المصب العام ١٦ الجديدة ٢ ٢٩٠ ٩٤ ١٣٢ المصب –ناصرية القديمة ١٧ العام ٢ ٥٦ ٢٣٫١ ١٣٢ ٢ ١٥ ٣٫٥ ١٣٢ شمال السماوة –سماوة ١٨ ٢ ٨ ٢ ١٣٢ ناصرية القديمة –ناصرية ١٩ ٢ ١٦٧ ٥٧٫٥ ١٣٢ عمارة -رفاعي ٢٠ ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٧ يبين شدة التلوث التي تتعرض له اسطح العوازل) ١(الشكل عازل ملوث تالف بسبب الومضة العابرة) ٢(الشكل ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٨ 132kv)( المستخدمة في خطوط )cap and pin(يبين ابعاد العوازل من نوع ) ٣(الشكل dimension in mm ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢٩ longrodن نوع يبين عازل ملوث م) ٤(الشكل longrodيبين عازل ملوث تالف من نوع ) ٥(الشكل ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٣٠ 0 20 40 60 80 100 120 140 160 180 0 10 20 30 40 50 60 70 80 90 100 110 time(minute) v ol ta ge (k v ) 0 20 40 60 80 100 120 140 160 0 10 20 30 40 50 60 70 80 90 100 time(minute) v ol ta ge (k v ) على عازل جديد من نوع يبين عالقة الزمن مع الفولتية المسلطة ) ٦(الشكل )cap and pin( ) الرميثة-شمال السماوة( لخط )١٣٢ kv(يبين اداء عازل ) ٧(الشكل رقم flash ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٣١ 0 20 40 60 80 100 120 140 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 time(minute) v o lta ge (k v ) 0 20 40 60 80 100 120 140 0 5 10 15 20 25 30 35 40 45 50 55 60 65 time(minute) v o lta ge (k v ) ) سماوة-الناصرية ( لخط )١٣٢ kv(يبين اداء عازل ) ٨(الشكل رقم ) المصب العام-الناصرية القديمة ( لخط )١٣٢ kv(ازل يبين اداء ع) ٩(الشكل رقم flash flash ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٣٢ 0 20 40 60 80 100 120 0 10 20 30 40 50 time(minute) v o lta ge (k v ) 0 20 40 60 80 100 120 140 voltage (kv) 1 2 3 4 increase a mount of pollution ) رميلة الجديدة-المصب العام ( لخط )١٣٢ kv(يبين اداء عازل ) ١٠(الشكل رقم لجميع العوازل المفحوصة يبين قيم فولتيات الومضة العابرة) ١١(م الشكل رق للخطوط االربعة المنتخبة flash 14-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 activation of red kaolin clay as a pozzolanic material assistant lecturer: ali k. ibrahim highway and transportation engineering department college of engineering almustansiriyah university email: ali_kadhum79@yahoo.com abstract this work included two stages; in the first stage the optimum burning temperature to convert red kaolin clay to metakaolin was investigated. the red kaolin was burnt in a different temperature (800, 850, 900, 950, 1000, and 1050) ºc for one hour. many tests was carried out on the cement containing (8)% of calcined kaolin such as normal consistency, setting time, soundness, compressive strength at (3, 7, and 28) days, and pozzolanic activity index at (7, and 28) days. the results show that the optimum burning temperature to convert kaolin clay to metakaolin is (900) ºc. in the second stage the effect of replacing the red kaolin calcined at (900) ºc at a (5, 8, and 10) % by weight of cement on compressive strength of cement mortar at (3, 7, and 28) days, and compared the results with reference mix. the results shows that the mortars contains red kaolin have compressive strength less than the reference mix at (3, and 7) days, but it shows slightly increasing in the compressive strength at (28) day about (100.8, 102.5, and 103.4) % for the mixes containing (5, 8, and 10) % of red kaolin respectively. the results also showed that the mortar containing (10)% red kaolin gives higher compressive strength compared with the mortar containing (5, and 8)% red kaolin at (28) day. keywords: kaolin, red kaolin, cement, pozzolana, burning temperature. : مدرس مساعد –– ali_kadhum79@yahoo.com :االلكتروني ، )٩٠٠، ٨٠٠،٨٥٠ ،٩٥٠،١٠٠٠١٠٥٠ (º.ل)٨ ( %)٣، ٧٢٨() ٧٢٨ ( )٩٠٠ (º . )٩٠٠ (º)٣٧(ا) % ٥٨١٠ al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٢٨ ( )٩٠٠ (º)٣٧ ( )٨، ٥()% ١٠٠.٨،١٠٢.٥١٠٣.٤ ٢٨()% ١٠ ( . )٥() % ١٠ ٢٨() % ٨ (. nomenclature 10rm : mortar containing 10% red kaolin 5rm : mortar containing 5% red kaolin 8rm : mortar containing 8% red kaolin hrm : high reactivity metakaolin hrwra : high range water reducing admixture mk : metakaolin p.a.i : pozzolanic activity index ref : reference cement mortar sf : silica fume introduction kaolin clay is one of the raw materials of major importance for the ceramic and paper industry as well as for a number of auxiliary applications. there is an ongoing interest to apply kaolin clay in the construction industry as a raw material for the production of white cement clinker and as an artificial pozzolanic additive for concrete (in a form of metakaolin). kaolinite is composed of alternating layers of silicate (si2o5) and gibbsite (al2(oh)4). kaolinite crystals are usually arranged in pseudohexagonal plates forming flaky aggregates and it has the same chemistry as its polymorphs halloysite, dickite and nacrite. kaolin clay is formed as a result of the alteration of alumosilicates (feldspar, feldspathoid, spodumene, sillimanite) and volcanic glasses, sometimes altered by acidic hydrothermal solutions. besides kaolinite, kaolin clay usually contains different minerals (such as quartz, feldspar, and calcite). it is mostly white, but it also can be grey, yellow or red. a recent development comprises the application of metakaolin as an artificial pozzolanic additive for concrete. the strength and durability of conventional cementbased materials can be significantly improved when additives based on thermally activated kaolin are used. such additives are conventionally manufactured by firing high-grade purified kaolinite at 650-850 °c according to following reaction: 650-850 ºc 2sio2 · al2o3 · 2h2o 2sio2 · al2o3 + 2h2o (1) the main beneficial effect of metakaolin in concrete and cement systems is related to its high pozzolanic activity (its ability to react with portlandite, ca(oh)2 released during the hydration of portland cement). due to its ability to improve the packing of the cement matrix the application of super-fine particles of metakaolin results in a microfiller effect [aydin aras, et al]. the particle density of metakaolin is lower than that of portland cement. thus, when metakaolin is used as a replacement for cement the volume of cementitious materialis increased. reducing the sand content of the mix overcomes the effect of the increased volume of cementitious powder. [newman 2003]. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 previous researches metakaolin is a reactive aluminosilicate pozzolan formed by purified kaolinite clays at a specific temperature range and by grinding it to a high fineness. chemically, metakaolin encompasses as main constituents sio2 and al2o3, and in smaller quantities fe2o3, cao, mgo, so3, na2o and k2o. the efficiency of metakaolin as a pozzolan in cement and concrete is mainly governed by high content of sio2 and al2o3. the high pozzolanic activity is also due to the large portion of small particles of metakaolin [krajei, et al, 2007]. (ali k. ibrahim, 2005) investigates the optimum conditions to convert white kaolin clay to high reactivity metakaolin (hrm). this pozzolan is used with high range water reducing admixture (hrwra) to produce high performance lightweight aggregate concrete. the mechanical properties of this type of concrete are studied. he found that the most suitable burning temperature required to convert the kaolin clay into hrm was 700 0c, and the optimum time of burning was 1 hour. a. sadr momtazi et al studied the effect of iran's metakaolin in enhancing the concrete compressive strength. in this study, four different type of metakaolin which one of them was made in uk and the others were from different part of iran were used. sixteen mortar mixtures with different amount of calcinating kaolin were made. the substitution proportion of metakaolin used was 5%, 10%, 15% and 20% by weight of cement. about 380 cylinders specimens were made to determine compressive strength. the results indicate that the replacing metakaolin (mk) up to 20% has noticeable effect on compressive strength in comparing with mixture without metakaolin. also, shrinkage test was carried out on some specimens. the results show that shrinkage in specimens containing mk were almost the same as that in the pure cement specimens. m.m. morsy et al studied the effect of substitution of metakaolin (mk) by silica fume (sf) on thermal stability of portland cement-mk blended pastes. the kaolinte was thermally activated at 850°c for 2 hours. the cement pastes were prepared using standard water of consistency. the pastes were kept in moulds at 20°c and 100% relative humidity for 24 hours and then hydrated for 28 days under water. the hydrated pastes were exposed for 2 hours to temperature 200, 400, 600 and 800°c. the pre-heated specimens were tested for compressive strength, thermal stability, and microstructure and phase composition. the thermal shock resistances were performed on cement pastes after hydration. the results of investigation showed that the compressive strength of preheated blended cement increases with temperature up to 400°c and then, it decreases as the preheated temperatures increase up to 800°c. the replacement of portland cement, by 15% mk and 15% sf in cement pastes increases the thermal shock resistance by about 20 times than control. materials 1cement ordinary portland cement type (i) produced at lebanon cement factory (turabt sabia) is used in this work. it was stored in a dry place (air-tight containers) to avoid exposure to atmospheric condition. the chemical composition and physical properties of cement are shown in tables (1) and (2) respectively. test results indicate that the adopted cement conform to the iraqi specification no.5/1984. 2sand al-ekadir natural sand was used as a fine aggregate. table (3) and fig (1), illustrate the grading of sand used throughout this work. the grading of sand conforms to the requirement of astm c778-06. 3water tap water was used as mixing water for all mixes. 4high range water reducing admixture a modified condensation product of melamine and formaldehyde (melment l10) was used as a high range water reducing admixture (hrwra) of (5) % of weight of cement. 5red kaolin clay al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 the chemical composition of high reactivity metakaolin (hrm) is shown in table (4), it comprises nearly percent of (sio2 + al2o3 + fe2o3), which conforms to astm c618-05 class c pozzolan according to specification for natural and calcined pozzolans. optimum burning temperature of red kaolin clay kaolin is soft, white clay resulting from the natural decomposition of feldspars and other clay minerals. it occurs widely in nature. it is used for making porcelain and china, as a filler in the manufacture of paper and textiles and as a medicinal absorbent. kaolinite is the principal mineral constituent of kaolin. when kaolin is heated to a temperature of 450 ºc dehydroxylation occurs and the hydrated aluminosilicates are converted to materials consisting predominantly of chemically combined aluminium, silicon and oxygen. the rate at which water of crystallization is removed increases with increasing temperature and at 600 ºc. metakaolin is formed in kilns when kaolin is heated at a temperature between 700 ºc and 800 ºc. the calcined product is cooled rapidly and ground to a fine powder. the metakaolin formed in this way has a highly disorganized structure [newman, 2003]. in the first stage many samples of red kaolin clay were burnt in a controlled temperature furnace at various temperatures (800, 850, 900, 950, 1000 and 1050) 0c to determine the optimum temperature of calcinations. after calcinations process the kaolin clay was left to cool, then it was grounded to have high fineness metakaolin and mixed with cement in porcelain mill for 30 minutes to ensure hrm particles were thoroughly dispersed throughout the cement particles. in this stage many tests such as normal consistency, setting time, soundness, compressive strength, and pozzolanic activity index, were investigated for each burning temperature. the pozzolanic activity index (p.a.i) was determined as follows, according to astm c311-05. p.a.i = (a/b) × 100 (2) where: a: average compressive strength of test mix cubes. b: average compressive strength of reference mix cubes. tables (5), and (6) and figures (2), (3), and (4) shows that the optimum burning temperature of the red kaolin clay is (900) 0c, which is exhibited higher compressive strength and higher pozzolanic activity index compared with all other burning temperatures at (28) day. compressive strength of mortars the effect of replacement of red kaolin burnt at (900) ºc as a (5, 8, 10) % by weight of cement on compressive strength of mortars was studied. (36) specimens of (50) mm cube is cast and cured according to (astm c 109/c 109m 05). the results shows that the reference mixes (ref.) have higher compressive strength at (3 and 7) days compared with the mixes containing red kaolin table (7) and fig. (5), but at (28) day the mixes containing red kaolin exhibited slightly higher compressive strength than reference mix. the results also showed that the mix containing (10) % red kaolin (10rm) gives slightly higher compressive strength at (28) day compared with all other mixes. this is due to the reaction between the amorphous silica of the pozzolanic and the calcium hydroxide produced by the cement hydration reactions. in addition, the physical effect of the fine grains allows denser packing within the cement and reduces the wall effect in the transition zone between the paste and aggregate. in general, the pozzolanic effect depends not only on the pozzolanic reaction, but also on the physical or filler effect of the smaller particles in the mixture [m.m. morsy et al, 2008]. conclusions 1the optimum burning temperature of red kaolin clay to gives best results with cement is (900) ºc. 2replacement of metakaolin slightly delays the setting time of cement paste. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 3the mortars containing red kaolin burnt at (900) ºc show slightly higher compressive strength than reference mortar at age (28) day although it have lower cement content. references metakaolin http://claisse.info/specialabstracts.htm ,pp. 1-7. ali k. ibrahim, aggregate co m.sc. thesis, university of technology, february, 2005, pp.101. astm c 109/c 109m 05 standard test method for compressive strength of hydraulic cement mortars (using2-in. or [50-mm] cube specimen annual book of astm standards, vol.04.02, 2006. astm c 151 05 annual book of astm standards, vol.04.02, 2006. astm c 187-04, standard test method for normal consistency of hy annual book of astm standards, vol.04.02, 2006. astm c 191 04b standard test methods for time of setting of hydraulic cement by annual book of astm standards, vol.04.02, 2005. astm c 311-05, "standard test methods for sampling and testing fly ash or natural pozzolans for use as a mineral admixture in portland cement concrete", annual book of astm standards, vol.04.02, 2006. astm c 618-05, "standard specification for fly ash and raw or calcined natural pozzolan for use as a mineral admixture in portland cement concrete", annual book of astm standard, vol. 04.02, 2006. astm c 778 06 specification for standard sand ", annual book of astm standards, vol.04.02, 2006. aydin aras, mustafa albayrak, 1-15. material for cemet 15, 2007,pp. 217-224. journal of civil engineering (building and housing) vol. 9, no. 2 (2008), pp. 93-105. constituent materials, first published 2003, pp. 280. (i.q.s) (i.q.s) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 table (1) chemical composition and main compounds of cement* oxides composition content % limits of (i.o.s.) no.5/1984 cao 63.52 sio2 19.57 al2o3 6.10 fe2o3 3 mgo 1.25 5.00 so3 2.73 2.80 l.o.i. 2.36 4.00 insoluble residue 0.76 1.5 lime saturation factor, l.s.f. 0.95 0.66-1.02 main compounds (bogue's equations) c3s 56.21 c2s 14.00 c3a 11.63 c4af 8.10 * chemical analysis was conducted by national center for construction laboratories and researches. table (2) physical properties of cement* physical properties test results limits of (i.o.s.)no.5/1984 specific surface area (blaine method), m2/kg 240 230 setting time (vicate apparatus), initial setting, h:min final setting, h:min 1:30 5:32 00:45 10:00 compressive strength, mpa 3 days 7 days 23.40 34.62 15.00 23.00 soundness (le-chateler ) method, mm 1.0 10 *physical analysis was conducted by national center for construction laboratories and researches. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 table (3) grading of fine aggregate table (4) chemical analysis of red kaolin clay oxide composition oxide content % sio2 40.54 al2o3 7.55 fe2o3 3.97 tio2 0.53 na2o 1.03 k2o 1.5 cao 21.87 mgo 4.65 so3 0.25 l.o.i 16.35 *chemical analysis was made by (state company of geological survey and mining). sieve size, mm cumulative % passing limits of astm c778 1.18 100 100 0.60 98 96-100 0.425 72 65-75 0.30 26 20-30 0.15 3 04 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 table (5) properties of cement with 8 % hrm at various burning temperatures cement with 8 % hrm replacementproperty 800 850 900 950 1000 1050 w/c ratio for standard consistency 0.3125 0.305 0.3075 0.3075 0.315 0.315 setting time(12) initial setting, h:min final setting, h:min 1:37 5:48 1:40 6:13 1:39 5:50 1:18 6:08 1:50 5:45 1:53 5:43 compressive strength, mpa 3 days 7 days 28 days 21.53 30.37 39.39 20.75 31.88 42.16 22.15 33.64 43.62 21.08 30.13 40.93 21.57 29.32 40.77 19.66 29.75 39.03 soundness (le-chatelier) method, mm 0.5 1.5 0.5 0.5 0.5 1.5 soundness (autoclave) method, % 0.26 0.23 0.23 0.25 0.6 0.27 table (6) pozzolanic activity index (p.a.i) at various burning temperatures table (7) compressive strength of reference and red kaolin mortars compressive strength, (mpa) mix symbol 3 days 7 days 28 days ref. 23.40 34.62 42.54 5rm 22.43 33.52 42.9 8rm 22.15 33.64 43.62 10rm 21.86 33.15 43.97 cement with 8 % hrm replacementproperty portland cement 800 850 900 950 1000 1050 w/c ratio to give flow of 100-110 % 0.53 0.552 0.54 0.544 0.548 0.56 0.56 pozzolanic activity index % at 7 days 28 days ------86.6 96.3 87.7 96.8 90.2 100.9 90.6 95.6 88.4 93.5 89.6 93.4 w/c ratio to give flow of 100-110 % with hrwra 0.385 0.392 0.4 0.408 0.412 0.42 0.42 pozzolanic activity index % with hrwra at 7 days 28 days ------87.3 92.8 88.6 98.6 91.4 102.3 87.1 94.4 89.1 91.6 85.2 92.8 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig (1) grading of sand fig (2) compressive strength of cement mortars containing (8) % of red kaolin burnt at different burning temperatures. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig (3) pozzolanic activity index of cement mortars containing (8) % of red kaolin burnt at different burning temperatures. fig (4) pozzolanic activity index of cement mortars containing hrwra and (8) % of red kaolin burnt at different burning temperatures. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig (5) compressive strength of reference and red kaolin mortars. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 180 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. spring back prediction in v-die bending process using artificial neural network (ann) mostafa adel abdullah, department of production engineering and metallurgy university of technology , baghdad. iraq email: mostafa_ad_87@yahoo.com received on 30 november 2016 accepted on 4 april 2017 abstract: the bending process is the critical operation in the sheet forming, there are large parameters influence on operation. spring back is considering large influential indication to specify the quality of product parts. the basic parameters which are takes to study in this paper are: speed of punch, time of hold and thickness of plate. experiment use l16 array with four levels for every parameters using v-bending die with 90 0 , with different thickness of (0.5,1,1.5,2) mm ,hold time (0,5,10,15) min and punch speed(10,20,50,100)mm/min, for (1050) al –alloy having employed as the work pieces. spring back value prediction use artificial neural network with conventional configuration. the results show that the thickness of plate is the large influential parameter effect in spring back by 77.29%, then punch speed by 10.51% and hold time by 3.36%. the predict result using artificial neural network shown a best accuracy with (99.35%) in spring back compared to the measured value. keywords: spring back, bending process, artificial neural network(ann),prediction. 1. introduction spring-back is a general event that happens in sheet metal when bend it after remove load apply because elastic recover. when the bending process removes elastic power stay in the bending plate cause it to repair part to begin shape and this is called spring back. spring-back ratio (ks) mean(the ratio between the die angle and final bending angle). the experiment worked for various shapes, and processes and material condition [1]. large of the studies focus on vdie bending operation. leu, d-k [2008][2] study the spring-back in v-bending was effectived by the bend radius, punch speed and punch load and also a few important literatures are briefly discussed here. yoshida[2005] [3], studied a forming process to minimize springback for steel sheet part made with large strength. yanagimoto,j.oyamada[2006] [4],studied the effect of many parameters on spring back phenomenon at worm and hot condition and study the effect of hold time on this condition, and founded that the spring back decreases with an increase of hold time. zhu l, beaudoin[2004] [5], presents outline of a simple bending test to study stress levels the evolution of stress and development of plastic strain with time are assessed easy analysis of spring back process and the micro plastic that causes distortion of the bent metal which a model developed by garmestani and hart.in recent research has been considered the different parameters which affected on spring back phenomenon. ali ghoddosian[2015][6] prediction and reduce the responses of the sheet metal bending process using artificial neural network (ann) and genetic algorithm(ga). gawade sharad[2014][7] used easy neural network is used for prediction the springback from finite element analysis. the results get by finite element analysis simulations compared with neural network and found in large agreement. mailto:mostafa_ad_87@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 181 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2. basic theories of spring back materials divided for two deformation, zones first the elasticity and then the plastic zone . in bend process, this recovery of elasticity called spring back, spring back phenomenon is shown in figure.( 1) the larger bent radius change with after than before bending process. spring-back happen in flat sheets , plate, rod and bar with different cross-section [8]. spring back, mean as the increase in the angle of the bent part proportional to the included angle of the forming tool after the tool removes. this is illustrated in figure. 1 : spring back = αf αb , ks = αb / αf where : αf = angle after spring back(degee) αb = angle of bending tool (degee) ks = spring back ratio figure 1. spring-back in bending process [6]. 3. theory of taguchi method taguchi method is a powerful tool for the design of high quality systems. it provides systematic approach, simple and efficient to optimize designs for cost, quality and performance .to determine the good design it requires the use of a strategically designed experiment for choices parameter level [10]. 4. experimental work 4.1. machine used a wdw model (200e)electro mechanical load frame (200kn) shown in figure 2. experimental work for the specimens in bending die used in as show in the figure 3. 4.2. material used the specimens for spring back test were manufactured these specimens must fit the die and punch with a suitable clearance about (1mm) with a v-die. a rectangular sheet of 50 mm of width and 100 mm. aluminum alloy 1050 which the chemical composition is listed below in table 1. is used as a work piece with (0.5,1,1.5,2) mm thickness. αb αf al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 182 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 2. uniaxial tensile testing figure 3. the v-die bending use. table 1. chemical composition of alalloy (1050). material thickness element % si fe cu mn mg zn ti al other 0.5 mm 0.25 0.40 0.05 0.05 0.05 0.07 0.05 99.4 0.030 1 mm 0.21 0.32 0.03 0.04 0.05 0.07 0.04 99.3 0.042 1.5 mm 0.24 0.38 0.03 0.03 0.04 0.06 0.03 99.1 0.045 2 mm 0.19 0.30 0.02 0.04 0.05 0.06 0.05 99.3 0.041 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 183 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.3. design of cutting condation the good design of cutting condition important part on the numeral of work to occur low cost and good output with minimum sample. the all numeral of cutting condition is (64 sample) based on four levels three parameters. a partial factor design was done use (16 sample) to obtain spring back values at room temperature. the parameters were t, s, th the levels and units of condition are listed below in the table 2. table 2. condition level used in work units level 4 level 3 level 2 level 1 symbol parameter no mm 2 1.5 1 0.5 t thickness 1 mm/min 100 50 20 10 s punch speed 2 min 15 10 5 0 th hold time 3 4.4. spring back test a 90 0 (veebending die) is applied to action the bending operation . the die is comparison load with (200) kn used a wdw model (200e), work piece dimension use(100*50)mm as shown step in figure.4 and spring back measure for al-alloy as shown in figure.5. figure .4 the experimental setup step of v-bending process figure .5 spring back measures for al-alloy work al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 184 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the final distribution of the experiments sample as listed below in table .3 with using taguchi method and design in minitab16 software as follows step: table .3 experimental design for the work no thickness (mm) punch speed (mm/min) hold time (min) springback measure (degree) 1 0.5 10 0 12.5 2 0.5 20 5 10.6 3 0.5 50 10 8.5 4 0.5 100 15 7.8 5 1 10 5 10.5 6 1 20 0 8.2 7 1 50 15 9.1 8 1 100 10 7.1 9 1.5 10 10 8.3 10 1.5 20 15 5.8 11 1.5 50 0 6 12 1.5 100 5 4 13 2 10 15 2.3 14 2 20 10 3 15 2 50 5 3.5 16 2 100 0 4.1 5. artificial neural network modeling ann is a multi layered method putting between the input layers and output layers with included many operation part call with neurons [11]: where netj : input net n :no of inputs wij is the weighing of the connection xi : input of the layers outj :output network [12]: al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 185 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the designed using matlab neural network toolbox with three inputs parameter and one output parameter using as shown in figure.6 . the divide of cutting condition to 16 groups a 12 groups or 75% as training and 4 groups or 25% as testing data. the final sequence design used with 3-5-1 . figure .6 sequence design used. to find the accuracy of the predict (ann) percentages errors and average percentages errors [13]: = …… (3) where: φi= percentages errors. raie=measuring spring back. raip= predicting spring back. (4) where = average percentages errors. m= no of e measuring. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 186 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 6. results & discussion analysis of variance: the anova of spring back are shown in table .3 for work. the f ratio value of 5.9933 for the thickness of plate which greater than other parameters. so, the large affect parameter is the thickness of plate with (77.29%) than the hold time and punch speed. figure .7 shows the main effect parameter in spring back with increases (thickness, punch speed and hold time) lead to decreases spring back. the minimum spring back was: thickness at level-4 (2 mm), punch speed at level-4(100 mm/min), and hold time at level-4(15 min). figure .8 shows the effect of the thickness of the plate and punch speed on spring back at a fixed hold time. it showed the decrease in spring back with increase the thickness of plate and increase punch speed. table .3 anova for spring back. source of variance degree sum of squares variance f ratio p(%) thickness (mm) 3 105.17 35.06 5.9933 77.29 punch speed(mm/min) 3 14.3 4.8 0.7890 10.51 hold time(min) 3 4.6 1.5 0.2493 3.36 error ,e 3 12.03 4.01 -- 8.83 total 16 136.1 ----100 figure .7 mean effects plot for spring back. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 187 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure .8 effect of thickness of plate and punch speed on the value of spring back at a constant hold time. figure. 9 shows the effect of thickness of plate and hold time on spring back at a fixed punch speed. it shown decrease in spring back with increase the thickness of plate and increase hold time . figure .9 effect of thickness of plate and hold time on spring back at a constant punch speed. the results shown in table .4 . these results are developed to predict spring back using artificial neural network (ann). using a given three input (thickness of plate, punch speed and hold time) and output (spring back) data set. training data depend of 12 as listed below in table .4 and test data depend 4 of data as listed below show in table .5 . the training error for predicting spring back value must be lower than (0.008) at 12 , as shown in figure .10 and figure.12 and shown error value in figure .11 . table .4 compare for result work measure and (ann) results for the spring back, respectively. the ann predicted spring back shown a perfect correlation with the experimenter, (mean square error =0. 0058). and show the methods using to predict the spring back in a minimum error rate for bending process. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 188 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table .4 the experimental training results. no thickness (mm) punch speed (mm/min) hold time (min) springback measure (degree) springback prediction (degree) 1 0.5 10 0 12.5 12.49 3 0.5 50 10 8.5 9.38 4 0.5 100 15 7.8 7.79 5 1 10 5 10.5 10.49 7 1 50 15 9.1 9.09 8 1 100 10 7.1 7.10 9 1.5 10 10 8.3 8.29 11 1.5 50 0 6 5.99 12 1.5 100 5 4 4.17 13 2 10 15 2.3 2.66 15 2 50 5 3.5 3.77 16 2 100 0 4.1 4.10 table (5) correlation of neural network predict with experiment measure using test set data. no thickness (mm) punch speed (mm/min) hold time (min) springback (degree) error ann result measure prediction mse accuracy 2 0.5 20 5 10.6 10.61 0.09 0.65 0.0058 99.35% 6 1 20 0 8.2 8.35 1.83 10 1.5 20 15 5.8 5.78 0.34 14 2 20 10 3 2.99 0.33 figure .10 the correlation between the measure with the prediction of spring back for train set data. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 189 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure .11 regression graphs to model. figure .12 the correlation between the measures and the prediction of spring back for test set data. 7. conclusions in this study, the effect of various bending parameters (thickness of plate, punch speed and hold time) on spring back as a result of application (1050) alalloy and predicting the values of spring back using of ann. figure .10 shows the correlation between experiment and predicted given accuracy with (99.35%) for spring back using data for training purpose. the ann is represent a good simple design and fasting method for the bending process production. from anova results, it can be achieve that thickness of plate is the most importantly parameters effecting spring back by 77.29%, then punch speed with 10.51% and hold time with 3.36%. the combination of conditions and their levels (punch speed 100 mm/min, thickness of plate 2 mm and hold time 15 min) are recommended to obtain a lowest spring back for vdie bending aluminum sheet 1050 alloy. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 190 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. references 1. da sisva botelho, da sisva botelho, t. e. bayraktar, g.nglebert.comparison of experimental and simulation results of 2d –draw -bend springback „in the journal of achievements in materials and manufacturing vol. 18 ,2006,pg. 275-278 . 2. leu, d-k c-m hsieh. the influence of coining force on spring-back reduction in v-die bending process„ in the journal of materials processing technology, 2008,pg. 230-235. 3. yanagimoto, j. and oyamada, k. spring-back of high strength steel after hot and warm sheet forming„ in the annals of the cirp,vol. 54 (1), 2005,pg. 213-216. 4. yanagimoto,j.oyamada .spring back free isothermal forming of high strength stress sheets and aluminum alloy sheets under worm and hot forming condition int,, in the .vol. 46, 2006,pg. 1324-1328. 5. zhu l, beaudoin aj, macewen sr .an assessment of in service stress relaxation of a work-hardened aluminum magnesium alloy,,in asme j. eng.mater technol. 2004, vol.126 ,pg. 157–163. 6. ali ghoddosian, navid nouredin, mojtaba sheikhi. using neural network and genetic algorithm for spring back minimization in sheet metal formin,,in the report and opinion, vol. 7 (2), 2015,pg. 74-278. 7. gawade sharad , dr. v. m. nandedkar. springback in sheet metal u bending-fea and neural network approach,, in the procedia materials science vol (6), 2014, pg 835 – 839. 8. cupka, v. t. nakagawa, and h. tyamoto. manufacturing processes for engineering materials. kalpakjian schmid, 5th ed ,2008. 9. hongman kim, statistical modeling of simulation errors and three reduction via response surface technique. adissertation submitted to the faculty of the virginia polytechnic institute and state university, 2001. 10.abbas khammas. optimization of cyclic oxidation parameters in steel-t21 for aluminization coating using taguchi-anova analysis byminitab13,, in the eng. & tech. journal, vol. 27, no.12, 2009. 11. hasan. o, tuncay. e and fehmi. e.prediction of minimum surface roughness in end milling mold parts using neural network and genetic algorithm,, in the materials and design, vol.27,2006. pg.735–744. 12. babur. o ,hasan. o and hasan. k.optimum surface roughness in end milling inconel 718 by coupling neural network model and genetic algorithm,,in the int j adv manuf technol,vol.27,pg.234–241,2005. 13. prakasvudhisarn. s, kunnapapdeelert, and yenradee. p, optimal cutting condition determination for desired surface roughness in end milling,, in the int j adv manuf technol, vol. 41,2009, pg.440 – 451. http://link.springer.com/search?facet-author=%22siwaporn+kunnapapdeelert%22 http://link.springer.com/search?facet-author=%22pisal+yenradee%22 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 354 study the effect of the variation of layer's thickness on the bending characteristics of the composite beam assist. lecturer manal hameed jasem al-mustansiriya university/college of eng./mech. eng. depart. abstract the analysis bending characteristics of the composite specimen formed from steel and aluminum sheets with different thicknesses were studied here experimentally, theoretically and numerically by using finite element method. the results show that the deflection decreases in nonlinear relationship with increase steel thickness, the maximum difference for the deflection between the experimental and finite element results was (11 %). while the modulii of elasticity and equivalent stiffness of the composite specimen increases with the increase the steel thickness. also the results show that the tension and compression stresses change to the bottom surface and to the top surface of the composite specimen and that depend on the position of neutral axis of the this specimen. keyword: composite, beam, bending, stiffness, neutral axis, deflection (11%) manal hameed jasem 355al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 nomenclature symbols definition unit b width of the composite beam. (m) ei modulus of elasticity of each constituent (i). (n/m 2 ) est and eal modulus of elasticity of steel and aluminum respectively. (n/m 2 ) e.i equivalent stiffness. (n.m 2 ) ho, h1, & h2 height of layer from the bottom surface (ho=0). (m) l length of the beam. (m) m bending moment. (n.m) p applied load at the midpoint of the beam. (n) r radius of curvature. (m) vi volume fraction of each constituent (i). % vst and val volume fraction of steel and aluminum. % νst and νal poisson's ratio of steel and aluminum respectively. introduction bending analysis of the laminated composite beam depend on the position of neutral axis, thickness of layers which effect on the central deflection of the three point bending test, equivalent stiffness, modulus of elasticity and tension and compression stresses. one of the most important advantages obtained of the advanced composite materials lies in the possibility of getting composite materials of a suitable laminated structure of plates by arranging them with sheets. laminated composite material consists of multi layers of various materials [1]. therefore many studies have been accomplished to obtain composite materials suitable for practical applications. bareisis and kleiza, 2009 suggested a mathematical model for calculating the bending stiffness and fields of normal stresses at any point in the cross section of a multilayer beam. it is found from the example of two-layer beams that the normal stresses in multilayer beams under a symmetric bending considerably depend on the location of the flexural center, neutral plane, and bending stiffness relative to the principal axes of cross sections of the beams [2]. yaghoobi and fereidoon, 2010 investigated the bending analysis of functionally graded simply supported beam subjected to a uniformly distribution load and found that the position of neutral surface position and the central deflection depend on the material properties of the beam vary continuously in the thickness direction [3]. simon etal, 2007 proposed a mathematical model and derived its analytical solution for the analysis of the geometrically and materially linear two-layer beams with different material and geometric characteristics of an individual layer by taking into account the effect of the transverse shear deformation on displacements in each layer [4]. bareisis 2006 obtained equations allow establishing the positions of neutral layers and of the geometric, stiffness centers, stiffness for bending and shear, and calculating normal and shear stresses which depend on the mechanical properties of layers, number of layers, and their arrangement and dimensions [5]. jingfeng and guoqiang, 2008 measured the stresses and deflections in various semicontinuous beams and the results show that the semi-cotinous composite beam are more economic and effective than the simple or continous beams. also the semi-rigid connections affect the bending capacities and beam deflections [6]. ahmadreza and luc, 2008 presented analytical model describes and improved smalldeflection for piezoelectric bending beam actuators and energy conversion mechanism. this model provides an improved approach to design and analyze the performance of piezoelectric actuators [7]. garuckas and bareisis, 2003 investigated the bending stiffness and strength of multilayer structural elements in relation to the mechanical properties of layers and their number layout and study the effect of the variation of layer's thickness on the bending characteristics of the composite beam al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012356 sizes. it is found that the values of normal stresses in the layers of a multilayer beam in bending on its bending stiffness and position of layers relative to the neutral axis [8]. the composite beam used in this research was made from two layers of isotropic materials (steel and aluminum) with different thicknesses. the aim of this work is to study the variation of layer's thickness on the bending analysis of laminated composite beam which represented by the position of neutral axis, central deflection, equivalent stiffness, modulii of elasticity in both direction( longitudinal and perpendicular ) and tension and compression stresses using experimental, theoretical and finite element analysis by using ansys package. also make a comparison between some results of experimental and finite element analysis. theoretical analysis bending analysis of the composite beam depend on their constituents of layers, thickness of layers and geometry. the position of neutral axis for figure 1 can be calculated from the following equation (1) [9]:         1201 2 1 2 2 2 0 2 1 0 2 1 hhehhe hhehhe y alst alst    (1) the beam bending problem may be solved in the usual fashion except the "ei" will be replaced by the function "s" (equivalent stiffness) computed from the relation [9].           212203132202103031 3232 6 hhyhhehhyhhe b mrs alst  (2) s=m.r=e.i from the values of equivalent stiffness and simple bending beam theory so as determine the theoretical value of central deflection and stresses [10]: ie48 lp δ 3    (3) and from simple bending theory of the beam r e i m y   (4) the following equation was used to calculate the tension and compression stresses on the bottom and upper surfaces of the beam. i ym   (5) manal hameed jasem 357al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 the rule of mixtures was used here to predict the elastic constants of the composite material. one of them modulus of elasticity in the longitudinal direction of the beam (e1) can be calculated by the following formula: alalstst n 1i ii1 vevevee    (6) the second one of modulus of elasticity in the perpendicular direction (e2 = e3) can be calculated from the following formula [9]: al al st st n 1i i i 32 e v e v e v e 1 e 1    (7) also the poisson's ratio can be calculated from the following formula: alalst12 vv   st (8) bending analyses of the composite beam behave in a different manner from that of oneelement material. this difference may be viewed by deflection value and it may be higher or lower than that of the one element material according to the rule of mixture. experimental work the composite specimens were consists of two layers of different metals which represented by (steel and aluminum), some properties of these materials represented by table 1. these layers were cut from plates of steel and aluminum which has a different thickness in order to obtain the total thickness of the composite beam equal to (3 mm). the two layers of steel and aluminum were bonded by using epoxy adhesive, the bottom one is steel and the upper one is aluminum with different thicknesses. table 2 represents the variation of layer thickness of the composite beam. the geometry of the test specimen has a length of (100 mm) and width of (10 mm) and a thickness of (3 mm). figure 2 represents the three-point test apparatus with a test specimen of the bimetal composite beam and with some accessories. the composite beam is simply supported beam with central loading equal (0, 5, 7.5, 10, 12.5……….20 n). the deflection was measured by using dial gauge, fixed at the center of the top surface of the composite beam as shown from figure 2. the experimental work was carried out in the field to determine experimentally the central deflection of the composite test specimens by using dial gauge. modeling, element selection and mesh generation the specimens are treated as a two – dimensional problem with different layers thickness. the ansys package is used here for this type of analysis for the beam (three point bending test). two – dimensional element (solid 42) is used here to modeling of solid structure. this element is defined by four nodes having two degree of freedom at each node translations in the nodal x and y directions. the geometry, node locations, and coordinate system for this element are shown in figure 3 [11]. while for meshing the structure of the composite beam, it is necessary to discretize it into a sufficient number of elements. the mesh generation of this composite beam is shown in figure 4. study the effect of the variation of layer's thickness on the bending characteristics of the composite beam al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012358 results and discussion figures 5 & 6 represent the sample of deflection contours and stress contours of the composite beam specimen with length (100 mm), width (10 mm) and thickness (3 mm divided by 1.5 mm thickness to steel layer and 1.5 mm thickness to aluminum layer), at central load (p=10 n). figure 7(a-e) represents load-deflection curves for experimental and finite element analysis. it is clear that the deflection is increased approximately in linear relationship with increasing load at different rate. and the results of experimental work were higher than that of finite element analysis. the cause of difference between experimental and finite element results is due to the different between the experimental material properties of steel and aluminum that determine the experimental data of deflection and theoretical material properties that used to determine the numerical data of deflection. where the experimental results was higher than that of finite element analysis and the maximum difference was (11 %) at aluminum layer thickness =3mm and at central load (p=20 n) see figure 7 (a). figure 8 shows the relationship between the deflection and the layer thickness for experimental and finite element analysis at load (12.5 n). it is seen from these figures that the deflection decrease in nonlinear relationship with increase of steel thickness and vice versa the deflection increase with increase the thickness of aluminum layer that due to different in stiffness of these materials for both experimental and finite element method [10 & 11]. figure 9 shows the relationship between the tension and compression stress with the layer thickness. it is clear from this figure the tension stress reach the maximum value (σt= 16.357 mpa.) at layer thickness (0.75 mm steel + 2.25 mm aluminum) and then the tension stress decrease with increase the thickness of steel layer. also it can be seen that the compression stress reach the minimum value (σc=9.042 mpa.) at layer thickness (1.5 mm steel + 1.5 mm aluminum) and then the compression stress increases with increase the thickness of steel layer that due to the change in the position of neutral axis of laminated composite beam and that coming from inhomogeneous of the composite beam due to changing the thickness of each layer [5 & 8]. figure 10 shows the relationship between the position of neutral axis and the thickness of steel and aluminum layers. it is clear from this figure that the position of neutral axis decrease with increase thickness of steel layer and reach minimum value at ( 1.5 mm steel + 1.5 mm aluminum) and then increase with increase the layer thickness of steel layer that due to the changing in the thickness of each layer [3]. figure 11 shows the relationship between the equivalent stiffness and thickness of steel and aluminum layers. it is clear from this figure that the equivalent stiffness increase with the increase the thickness of steel layer and vice versa decrease with increase the thickness of aluminum layer in nonlinear relationship that due to the stiffness of each materials (i.e. tensile properties of steel higher than tensile properties of aluminum) in additional to increase the thickness of steel layer, because the equivalent stiffness equal to (ei) and this is consistent with the results of reference [2 & 8]. figure 12 shows the relationship between the modulus of elasticity in parallel and perpendicular direction to the composite beam with the thickness of the steel and aluminum layers. it is clear from this figure that the modulus of elasticity in parallel direction and modulus of elasticity in perpendicular direction increase linearly and nonlinearly relationship respectively with the increase the thickness of steel layer according to the rule of mixtures [1]. conclusions the following points were concluded from this result: 1-) the deflection decreases in nonlinear relationship with the increase the steel thickness for both experimentally and finite element results. 2-) the maximum difference for the deflection between the experimental and finite element results was (11 %). manal hameed jasem 359al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 3-) the tension and compression stresses change from bottom surface to top surface of the composite specimen which depend on the position of neutral axis. 4-) equivalent stiffness and modulii of elasticity in both directions increases with increase the steel thickness. references [1-] william d. callister j.," materials science and engineering –an introduction", sixth edition, john wiley and sons, inc., (2003). [2-] bareisis j. and kleiza v.," effect of layer geometry and stiffness on the fields of normal stresses in multilayer beams under asymmetric bending", journal of mechanics of composite materials, vol.45, no.4, (2009). [3-] h. yaghoobi and a. fereidoon," influence of neutral surface position of functionally graded beam under uniformly distributed load", idosi publications, world applied sciences journal, vol.10, no.3, (2010). [4] simon schnabl, mirna saje, goran turk, and igor planinc," analytical solution of two-layer beam taking into account interlayer slip and shear deformation", asce publication, journal of structure engineering, vol.133, no.6 (usa), (2007). [5] bareisis jonas," stiffness and strength of multilayer beams", royaume-uni publisher, journal of composite materials, vol.40, no.6, (london), (2006). [6] jingfeng wang and guoqiang li," bending and rotational behavior of semi-continuous composite beams", higher education press and springer, frontiers of architecture and civil engineering,vol.2, no.2, (china), (2008). [7] ahmadreza tabesh and luc g. frechette,"an improved small-deflection electromechanical model for piezoelectric bending beam actuators and energy harvesters", journal of micromechanics and microengineering, vol.18, no.10, (2008). [8] d. garuckas and j. bareisis," influence of different factors on the stiffness and strength of multilayer composite elements", journal of mechanics of composite materials, vol.39, no.2, (2003). [9] jones, r.m.," mechanics of composite materials", mcgraw-hill, (new york), (1975). [10] hearn, e.t.," mechanics of materials", pregaman press ltd vol.1, (1987). [11] kohnke p.," ansys: theory reference release 11", ansys, inc, canonsburg, pa, (2004). study the effect of the variation of layer's thickness on the bending characteristics of the composite beam al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012360 table 1 properties of materials used [1]. density g/cm 3 modulus of elasticity (gpa.) poisson's ratio tensile strength (mpa.) percentage elongation (%) steel 7.8 200 0.3 415 20 aluminum 2.71 69 0.33 90 40 table 2 variations of layer thickness and some properties of composite beam. composite beam steel layer thickness (mm) 3 2.25 1.5 0.75 0 aluminum layer thickness (mm) 0 0.75 1.5 2.25 3 total thickness (mm) 3 3 3 3 3 modulus of elasticity in the longitudinal direction (gpa.) 200 167.25 134.5 101.75 69 modulus of elasticity in the perpendicular direction (gpa.) 200 135.63 102.6 82.51 69 poisson's ratio in plane 1-2 0.3 0.3075 0.315 0.3225 0.33 volume fraction of steel % 100 75 50 25 0 volume fraction of aluminum % 0 25 50 75 100 figure 1 composite beam. figure 2 bending apparatus with specimen test. applied load specimen test manal hameed jasem 361al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 figure 3 two-dimentional element (solid-42) [12]. figure 4 mesh generation of the composite beam. study the effect of the variation of layer's thickness on the bending characteristics of the composite beam al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012362 figure 5 relationships between deflection and load for experimental and finite element method for the beam with length (100 mm). manal hameed jasem 363al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 figure 6 relationship between deflection and layer thickness of laminated composite beam for experimental and finite element method for the beam with length (100 mm) and central load (12.5 n) (equation3). figure 7 relationship between stress and layer thickness for laminated composite beam for the beam with length (100 mm) and load (10 n) (equation5). study the effect of the variation of layer's thickness on the bending characteristics of the composite beam al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012364 figure 8 relationship between position of neutral axis and layer thickness for laminated composite beam (equation 1). figure 9 relationship between equivalent stiffness and layer thickness for laminated composite beam (equation2). manal hameed jasem 365al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012 figure 10 relationship between modulus of elasticity and layer thickness for laminated composite beam (equation 6 and 7). study the effect of the variation of layer's thickness on the bending characteristics of the composite beam al-qadisiya journal for engineering sciences, vol. 5, no. 4, 354-366, year 2012366 figure 11 sample of deflection contours of laminated composite beam for 1.5 mm steel and 1.5 mm aluminum and at central load =10 n. figure 12 sample of stress contours of laminated composite beam for 1.5 mm steel and 1.5 mm aluminum and at central load =10 n. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 33 finite difference method for solving the dispersion equation in open channels dr. karim rashid gubashi head of environmental eng. dep. college of engineering al-mustansirya university abstract one dimensional advection-diffusion equation is numerically solved by using finite difference method that may be simulated to describe transport of a pollutant in open channel. a generalized newton raphson procedure is used to solve the system of equations. the validity of the numerical model is obtained by comparing the experimental results and numerical solution under proper initial and boundary conditions. the spatial variation of concentrations is also compared with the results of experimental measurement. the application of the model revealed good agreement and convincing between experimental and numerical results. keywords: dispersion equation, open channel, finite difference, one dimensional flow, pollution. طریقة الفروق المحدودة لحل معادلة التشتت في القنوات المفتوحة كریم رشید كباشي. د رئیس قسم ھندسة البیئة الجامعة المستنصریة/كلیة الھندسة الخالصة باستخدام طریقة الفروق المحدودة والتي تقوم بوصف انتقال الملوث في القناة عددیا التشتت -ھذا البحث یتناول حل معادلة االنتشار لبیان صحة تطبیق ھذا المودیل الریاضي . رفسن لحل نظام المعادالت المتكونة في المحددات-استخدمت طریقة نیوتن. المفتوحة تائج المختبریة مع الحل العددي تحت شروط وقیم ابتدائیة معینة وكذلك اجریت مقارنة بین تغیرات التراكیز اجریت مقارنة بین الن یظھر من تطبیق المودیل الریاضي بان ھناك تقارب واتفاق بین النتائج . المنتشرة مع المسافة الطولیة للقناة المختبریة والحل العددي .المختبریة والعددیة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 34 list of symbols c : concentration ( mg/l) u : instantaneous velocity in the x-direction (m/s). dx : coefficient of turbulent diffusion ( m2/s) θ : weighting factor. t∆ : time increment between j and j+1 (sec.). x∆ : distance increment between i and i+1 (m). bod: biochemical oxygen demand. d.o : dissolved oxygen introduction rivers have traditionally been used for the disposal of domestic and industrial waste waters. in many cases, this has caused undesirable changes to the aquatic flora and fauna. the majority of these changes have been brought about by the discharge of biochemical oxygen demand (bod) resulting in the lowering in the concentration of the dissolved oxygen (do) in the receiving water. pollution of rivers and estuaries is also frequently caused by the discharge of toxic substances, which may break down due to chemical or bacterial action (non-conservative) or which may be resistant to break down (conservative) and other problems may arise due to the discharge of inorganic nutrients causing excessive algal growth.( adrian, et al. , 1994) in all of these situations it is important to be able to relate the rate of discharge of the pollutant to resulting concentration pattern in the receiving water. various methods have been devised for calculating the pattern beginning with the classic work on bod/do models. this laid the basis for modeling the chemical kinetics of break down. subsequent work has concentrated on the hydrodynamic aspectsadvection and diffusion along with work on stochastic and statistical models and refinement of the kinetic models (barton, 1983). in this paper, the mathematical model of finite difference method for solution dispersion equation is developed. the convective diffusion equation to drive the equation of convective diffusion, consider an element volume is fixed in a fluid medium (thongmoon, et al., 2006). the flux of material into the element across plane is cu dy dz where u is the instantaneous velocity in the x direction and c is the concentration of the tracer injected. the net change in mass of material in the element from the flux in the x direction is al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 35 )( dzdydxcu x∂ ∂ − . equating the time rate of change of mass in the element with the rate of change due to the flux in each of three coordinate directions gives: 0= ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ z wc y vc x uc t c ……………..( 1 ) for simplicity, eq. (1) may be written in one dimensional form as: 0= ∂ ∂ + ∂ ∂ x uc t c ……..…...………( 2 ) if a tracer slug is injected at a point in a turbulent flow it will be subjected to two distinct processes (a) it will be swept along (advected) with a velocity comparable to that of the flow, (b) it will be mixed (diffused) due to turbulence, so that the tracer becomes more dilute, but its sphere of influence expands. a turbulent flow may be conceived as consisting of two constituents, namely a timeaveraged velocity, uav, and a fluctuating velocity uf so that v = u av + uf ………………...( 3 ) the concentration of the tracer in turbulent flow may be split into the two component (time average cav and fluctuating cf so that c = c av + cf ………………..(4) the equations (3) and (4) can be substituted into equation (2) and each term averaged to give: 0=++ ∂ ∂ ++ ∂ ∂ avfavfavfav uuccx cc t ).()()( …………(5) the differentials of products may be expanded giving 0= ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ avff av av av av av cu xx u c x c u t c )( …………(6) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 36 the form of 0= ∂ ∂ x uav in equation (6) is the continuity equation. equation (6) simplifies to 0= ∂ ∂ + ∂ ∂ + ∂ ∂ avff av av av cu xx c u t c )( …………….(7) the cross product terms such as uf cf represent the net convection of mass due to the turbulent fluctuations and with fick's law of molecular diffution they can be represented by an equivalent diffusive mass transport system in which the mass flux is proportional to the mean concentration gradient and the flux is in the direction of the mean concentration gradient. hence x c dcu avxff ∂ ∂ −=)( …………(8) where dx is coefficient of turbulent diffusion. equation (7) can be rewriting omitting the time average subscripts as 0= ∂ ∂ ∂ ∂ − ∂ ∂ + ∂ ∂ )( x c d xx c u t c x …………….(9) equation (9) is the one dimensional convective diffusion equation. values for the turbulent diffusion coefficient must be obtained from tracer measurements or by curve fitting exercise. numerical solution of advection diffusion equation a typical implicit approximation method ( preissmann scheme) approximates derivatives in the equation (9), leading to the following finite difference at node i: [ ] 022 2 1 2 1 11 1 1 11 12 1 11 11 11 1 =+−++− ∆ −    − ∆ − +− ∆ +−−+ ∆ −+ + − ++ + + ++ ++ ++ + j i j i j i j i j i j i x j i j i j i j i j i j i j i j i cccccc x d cc x cc x ucccc t )()()( θθ ……. (10) where θ is weighting factor , t∆ =time increment between j and j+1 and x∆ = distance increment between i and i+1 ( young,and wallis.,1993, and valentine and word, 1979) equation (10) is nonlinear with respect to the three unknown concentrations , c, at time j+1. however, one unknown is common for any two neighboring rectangular grid. consequently, the (n1) pairs of equations, in which n is the number of computational nodes in the channel, contains 2n unknown. two additional supplied by the boundary condition make this system of equations mathematically determinable. one boundary condition is specified at each end of the channel. a concentration is assumed at the inlet and outlet 0 1 1 cc j =+ …………………….. (11) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 37 l j n cc = +1 ……………………..(12) equations (10) , (11) and (12) are solved by using generalized newton raphson iteration method. computer program in quick basic is developed for numerical solution.a schematic of algorithm program for the model is presented in figure 2.( gubashi, 2000). solution of finite difference equation to illustrate the procedures that estimated to find a new unknown concentration at time j+1, it be assumed initial values of variables c are introduced into equations 10, 11, and 12, the right hand sides become the residuals. let the residuals be denoted by kir , and the system of equations may be represented in a genral way by k nnnn k k k o rccf rccf rccf rccf = = = = − ),( ........................ ........................ ),( ),( ),( 1 3323 2212 111 ……………. (13) in which f1 is the specified concentration at the inlet given by equation (11), f2 is the diffusion equation (10) at i , f3 is the equation (10) at cell i+1 and fn is the boundary condition at outlet. improved estimates are obtained by using newtonraphson recurrence formula for each time which results in the following set of equations: k nn n n k k k rdc fc f rdc c f dc c f rdc c f dc c f rdc c f −= ∂ ∂ −= ∂ ∂ + ∂ ∂ −= ∂ ∂ + ∂ ∂ −= ∂ ∂ .................................. ................................. 33 3 3 2 2 3 22 2 2 1 1 2 11 1 1 …………… (14) in which dci is the concentration correction for cell i for k th iteration cycle. equation (14) can be written as a x da = -b ………….. (15) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 38 in which a is a matrix of coefficients , da a column vector of corrections and b is a column vector of residuals from equations 10 to 12. the matrix a is banded about the center diagonal as shown in the following form:                                 ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ n n c f c f c f c f c f c f ................... ................... 3 3 2 3 2 2 1 2 1 1 ……….. (16) band solvers gaussian elimination method can be employed to provide the values of dci. then, the values of the variables of iteration cycle k+1 are obtained by the following form: i k i k i dccc += +1 ……………. (17) the computations can be terminated whenever the difference between the values of variable c in two consecutive iteration cycles falls below tolerance value. experimental studies laboratory experiments were carried out in a rectangular flume with dimensions, 20 m long, 0.9 m wide, and it constructed of steel structure with perspex panels walls of (1.2 cm), and the effective wide is 0.85m. water is pumped by an electrically driven centrifugal provide a maximum flow of (13 sl / ) to the flume from the laboratory sump tank (3.5 )3m and four small pumps with (0.5 sl / ). the discharge is regulated by a 4 inch gate-valve. the entrance to the flume is filled with filter material (multi short lengths of mesh wire 12mm) which served to break up any large eddies in the flow, water from the main sump under the laboratory flume is pumped at a fixed rate up to the header tank and entered large tanks at the end of the flume . a bed of plastic covered with 12mm broken gravel with a slope of 1:1416 is laid in the flume, the slope was chosen as representative of a natural open channel flow with the aspect ratios that could be obtained in the flume, as shown in plate(1) and figure 1. this flume is at hydraulic laboratory of the engineering college at al-mustansiriyah university (gubashi, et al., 2007). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 39 in these experiments pure kcl salt has been used as a tracer in water. twenty five runs are performed with different flow rate that varied between 0.5 and 12.5 l/s. results of concentrationtime profiles of kcl is shown in figure 3. results and discussion results of proposed numerical model are compared with that of laboratory experiments to calibrate and validate the proposed mathematical model. figure 4 shows experimental and numerical concentration-time profiles. the temporal and spatial of concentration in present model and experimental are plotted in figures 5 and 6. as shown in the figures the agreement between measured and numerical concentration profiles. the statistical correlation coefficient is presented in all figures and shows greater than 90%. conclusions a numerical model solution is used for determining the temporal and spatial variation of pollution concentration in open channel. the developed model is applied to a hypothetical flume conditions. the validity of the present model is shown by comparing with the results of the experimental solution under certain boundary and initial assumed conditions. the comparison presented good agreement between them and coefficients of square correlation, r2 are greater than ninety percent as shown in figures. references 1adrian, d.d.,yu.,f.x., and barbe, d., 1994. “ water quality modeling for a sinusoid ally varying waste discharge concentration.” water res., 28, 1167-1174. 2barton, n. g. ,1983. ” the dispersion of solute area time-dependent releases in parallel flows.” j. fluid mech., 136, 243-267 3-gubashi, k.r., 2000.” gradually varied unsteady flows in looped-channel network ph.d. thesis submitted to the dep. of building and construction, eng. of technology 4 gubashi, k.r., b.a. marouf and majeed k.m., 2007. “ an experimental study of radioactivity dispersion in open channels.” j. of tikrit eng. sciences, no.1, vol.14. 5thongmoon, m. and mckibbin, r., 2006.“a comparison of some numerical methods. for the advection-diffusion equation.” res.lett.inf. math. sci., vol 10, pp49-62. 6-valentine, e.m. and word, i.r., 1979, “ longitudinal dispersion with dead zones.” j. hydr. div., asce, 105(hy9), 975-990. 7young, p.c. and wallis, s.g., 1993. ” solute transport and dispersion in stream channels in: channel network hydrology (eds. k.j. beven and m.j. kirby) wiley, chichestor, 128-173. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 40 plate (1) general view of the flume. figure 1 layout diagram of laboratory flume al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 41 figure 2 layout of algorithm program start data input velocity of flow,u, ∆t,∆x, θ, dx initial and boundary conditions 0 1 1 cc j =+, l j n cc = +1 set equations as matrix system solution for the linear set non banded, non-symmetric equations j=j+1 assume c(i,j+1)=c(n,j+1) set equations as matrix system and solving by using newton-raphson method find calculations of all nodes end al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 42 0 200 400 600 800 1000 1200 time (sec.) 0 500 1000 1500 2000 2500 3000 3500 c on ce nt ra tio n (m g/ l) kcl (mg/l) at distance 9 m kcl (mg/l) at distance 18 m figure 3 kcl concentration-time profiles at distances 9 m and 18 m in flume 0 200 400 600 800 1000 1200 time (sec.) 0 500 1000 1500 2000 2500 3000 3500 c on ce nt ra tio n (m g/ l) q=0.56 l/s and at distance 9 m in flume measured numerical r2= 0.91 figure 4 comparison between numerical and experimental concentration-time profiles al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 43 200 400 600 800 1000 1200 time (sec.) 0 500 1000 1500 2000 c on ce nt ra tio n (m g/ l) q=0.56 l/s and at distance 18 m in flume measured numerical r2 = 0.94 figure 5 comparison between numerical and experimental concentration-time profiles 2 4 6 8 10 12 14 16 18 distance (m) 0 400 800 1200 1600 2000 c on ce nt ra tio n (m g/ l) q = 3.05 l/s measured numerical r2 = 0.97 figure 6 comparison between numerical and experimental spatial variation of concentration al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 314 parametric study on a prediction the drag coefficient for a single growing bubble in uniformly superheated pure liquids ali shakir baqir najaf technical college abstract a relation for predicting the drag coefficient for the process of bubble growing in a convective surrounding (uniformly superheated pure liquids) was developed. the non-dimensional parameters governing the motion and heat transfer are identified and a theoretical study of the effects of the variation of these parameters is made. the drag coefficient decreases with time for all accelerations, as well as with augmentation of the bubble acceleration at each instant of time, independently of the internal vapor parameters for bubble. the theoretical results obtained were agreeable with the previous theoretical data available with error ± 8.80 % % for non-dimensional time τ=1 and within ± 5.4 % for non-dimensional time τ=10. keyword: bubble growth, drag coefficient, non-dimensional parameters. على التنبأ بمعامل االعاقة لنمو فقاعة داخل سوائل منتظمة نقية المعامالت راسةد محمصة علي شاكر باقر الكلية التقنية النجف الموجز بمعامل االعاقة في اجراء نمو فقاعة في بيئة متعلقة بحمل حراري )سووائل منتمموة نقيوة للتنبأ عالقة تم تطوير محمصة (. تم التحقق من المعامالت غير البعدية السائدة او المسيطرة على الحركة وانتقال الحرارة ودراسة تأثير ختلف التعجويالت باالاوافة تغيير هذه العوامل على نمو وتكوين الفقاعة. معامل السحب ينخفض مع الزمن لم الووى ذلوون فووان تعزيووز تعجيوول الفقاعووة لكوول زموون لحمووي يكووون ببووكل مسووتقل لمعووامالت البخووار الداخليووة للفقاعووة. =τ 1للمعامول % 8.80 ±أبنسوبة خطو السابقِة النمريِة المتووفرةِ متوافقة مع البياناتالَنتاِئج النمرية َكانْت .τ=10للمعامل % 5.4 ±و symbols cd coefficient of drag cp specific heat at constant pressure, kj/kg k fr froude number g gravitational acceleration (m/s 2 ) acceleration ratio h heat transfer coefficient, w/m 2 k hfg latent heat of vaporization of the bubble (j/kg) ali shakir baqir 315 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 ja jacob number, 2333 tcp  / 1 k thermal conductivity (w/m. k) nu nuselt number, h(2r)/k pe peclet number, u(2r)/α r polar coordinate, m t absolute temperature, k t time, s ub bubble velocity, m/s ur radial component of liquid velocity, m/s uθ tangential component of fluid velocity, m/s greek α thermal diffusivity, m 2 /s θ polar coordinates φ velocity potential ρ liquid density (distilled water), kg/m 3 τ dimensionless time subscripts l liquid phase v vapor phase introduction bubble growth is the basis of the process of desalination of sea or brackish water by freezing. the other important industrial applications are the design and development of an efficient type of heat exchanger without internal piping. boiling is one of the most efficient ways to achieve high heat fluxes at a reasonable wall superheat. the high heat transfer coefficients that can be achieved are of utmost interest for many applications in the field of refrigeration, cooling of electronic devices as well as power generation (christian k. and peter s., 2010). fully quantitative predictive models are still under development, since they require information about heat transfer mechanisms derived from theoretical models and from detailed experiments on bubble dynamics (hetsroni g. et al, 2006). in formulating the problem of the flow past a bubble, a difficulty arises in connection with the modeling of the mechanical properties of the phase interface. the classic assumption is the continuity of the shear stress on the interface. then the viscous drag on a gas bubble of constant radius at small reynolds numbers can be calculated using the hadamard-rybchinsky formula. however, it has proved that the stokes formula for a rigid sphere gives a better description of experiments with rising gas bubbles. this formula was obtained on the assumption that the fluid velocity on the bubble surface is equal to the velocity of the bubble center of mass, i.e. that the surface withstands any shear stress. a numerical approach to the drag coefficients of spherical particles can be made up to a reynolds number range of several hundreds, but even this range is not wide enough to cover the necessary reynolds number range needed for practical use. consequently, correlations of the drag coefficients applicable for a wide range of reynolds numbers based on sufficiently reliable experimental data are needed (koichi asano, 2006). (lapple and shepherd, 1940) first proposed their famous correlation for the drag coefficients of a spherical particle based on a wide range of experimental data. many correlations have been reported, which are well summarized by (clift et al., 1978) among which is the useful correlation by (brauer and sucker, 1978). parametric study on a prediction the drag coefficient for a single growing bubble in uniformly superheated pure liquids al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 316 for an evaluation of the drag force of a growing vapor bubble at rectilinear accelerated ascension, (askovic, 2002) developed a simple relation for predicting the drag coefficient by applying the inviscid approximation. he investigated analytically that drag coefficient decreases with time for all accelerations. bubble growth rates were extensively investigated in the last few decades. generally, the work has been initially divided into the following two main regions : growth rates controlled by inertia forces, applicable in the range of a relatively low pressure and high jakob numbers, e.g. rayleigh and growth rates for heat diffusion controlled growth, e.g. (plesset and zwick, 1954). (birkhoff et al., 1954). (lien and griffith, 1969) experimentally investigated bubble growth in uniformly superheated water covering the low pressure range. they concluded that the bubble growth at very low pressure is controlled solely by inertia forces and that, as the pressure increases heat diffusion becomes a predominant factor, which at the upper part of their pressure range completely controlled the bubble growth. they also found that the interface resistance at the vapor-liquid interface has no significant factor on bubble growth. knowledge of the heat and mass transfer associated with a moving bubble or droplet is of importance to a variety of industrial processes. (boussinesque, 1905) has been the first to obtain a solution for the heat transfer rate from a fluid sphere of uniform and constant surface temperature, moving at a constant speed in another fluid of infinite extent. (ruckenstein, 1959) studied the heat transfer between a vapor bubble in motion and the liquid from which the bubble was generated. amongst the relatively small number of papers on deforming bubble in movement, the most often is used an impulsively started motion in a quiescent liquid initially at rest. generally speaking, the viscous effect is small when the reynolds number exceeds two or three hundred. it may be of interest to note that if the hydrodynamic boundary layers are developing simultaneously with the thermal boundary layer, the in viscid approximation is even better (k. stewartson, 1960). (dominique legendre et al., 1998) studied the heat transfer rate and the hydrodynamic forces experienced by a single vapor bubble of variable radius moving in a superheated or subcooled liquid by means of numerical simulation. they solved for that purpose the full navier–stokes equations and the temperature equation are in a frame of reference where the bubble surface is steady. they determined the time evolution of the bubble radius by solving the energy balance at the bubble surface. (kendoush, 2004) derived n analytical equation for prediction the drag coefficient of growing bubble in terms of reynolds, peclet, jakob numbers and dimensionless time. as no exact relation for drag coefficient for the case of an evaporating and moving bubble in superheated liquid, the relation for the drag coefficient of drag, applicable to motion of bubbles in superheated liquid, found in this work. in spite of a large number of theoretical and experimental investigations, a generalized theoretical analysis of bubble growing in a convective surrounding (uniformly superheated pure liquids) is found to be lacking in the literature. (even askovic, 2002) investigated that the drag coefficient decreases with time for all acceleration but he not study the non-dimensional parameters effect on the drag coefficient. a study of the various parameters governing the bubble growth process is essential to understand the phenomenon bubble growth in a convective surrounding. the present investigation deals with a parametric study of single bubble growth. it also aims to predict the bubble growth process in any uniformly superheated pure liquids. theoretical analysis for the problem of rectilinear and accelerated movement of a sphere in an in viscid stationary fluid (koichi asano, 2006, askovic, 2002, battya, et al., 1984) the velocity potential ϕ, and the normal vr and tangential vθ velocity components of the in viscid fluid flowing past a spherical particle of variable radius r are as follows (1) ali shakir baqir 317 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 (2) (3) where r is the radius-vector, is the angle between the radius-vector, is the bubble velocity, = dr/dt , is the bubble expansion rate and where r is the bubble radius as shown in figure 1; to calculate the pressure distribution on the bubble surface, using the bernoulli equation for the external unsteady flow (askovic, 2002): [ ( ) ] [ ( ) ] (4) where ( ) [ ] (5) differentiate eq. (1) respect to time t and substitute with equations (2) and (3) in eq. (5) yields: ( ) ( ̈ ) ( ) (6) the total drag force d of a growing vapor bubble at an accelerated ascension can be expressed as the sum of the three forces contributed by friction, pressure and evaporation. it can be written as: rr f 8 ∫ (7) where the first term is the friction drag force(kendoush, 2005) and the last term represents the buoyancy force experienced by the bubble. substitute eq. (6) in eq. (7), after integration, yields: rr f 8 (8) it is customary to introduce the drag coefficient cd, defined by: (9) substitute eq. (8) in eq. (9) , we obtain: rr f 8 (10) a combination of energy and mass balance results in the following relation for the bubble growth rate (mokhtarzadeh m.r. and a.a. el-shirbini, 1985): (11) eq. (10) can be transferred in the dimensionless form as: parametric study on a prediction the drag coefficient for a single growing bubble in uniformly superheated pure liquids al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 318 [ √ ] [ ] (12) where (13) where (14) (15) (16) (17) (18) (19) (20) (21) (22) (sideman and taitel, 1964) have obtained experimentally the instantaneous heat transfer coefficients for three different systems with various drop diameters and at several temperature differences and percentages of evaporation. the present analysis is carried out using their experimental values and the following correlation is obtained: (23) this relation is used in this work for the calculation of the instantaneous nusselt number. the temperature of the uniformly superheated pure liquid is assumed to be constant throughout the column for raising the bubble. the effect of the hydrostatic head is not considered for smaller bubble or high temperature differences. the properties of the fluids at the appropriate temperatures are obtained from the published literature and transferred to non-dimensional parameters (battya et al., 1984) and they printed on the figures. substitute eq. (23) in eq. (12) and rearrangement yields: [ √ ] [ ] (24) ali shakir baqir 319 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 results and discussion in this study, presenting the effect of non-dimensional parameters on the drag coefficient, the equation (10) which is the similar to the equation obtained by (askovic, 2002)but with addition of the shear force effect which is obtained by (kendoush, 2005) and we got on equation (24) with non-dimensional parameters. equation (24) depends on parameters ja, fr, pe, τ and . the available experimental data taken in this work is from experimental results of (sideman and taitel, 1964) and (battya, 1984), when single pentane drop-bubble of 3.6, 3.62 and 3.2 mm diameter evaporate along a column of distilled water at ∆t= 1.6, 3.8 and 8 k, respectively. figures 2-4 show the variation of the drag coefficient cd with non-dimensional time τ for some arbitrarily assigned values of the acceleration parameter: =4, 5, and 6 and varies non-dimensional parameters ja, fr, pe,. it is clearly shown that when the acceleration parameter increases the drag coefficient increases at low dimensionless time due to decreases in bubble acceleration . figures 2-4 predict the drag coefficient for the process of bubble growing in a convective surrounding (uniformly superheated pure liquids). figure 5 shows the effect of prandtl number. a higher prandtl number decreases the bubble growth rate. a higher prandtl number decreases the drag coefficient. figure 6 indicates the important of system jakob number. therefore, a higher jacob number increases the bubble growth rate and reduces the nusselt number. a higher bubble growth rate is accompanied by a higher acceleration of the bubble. therefore, a higher jakob number increases the drag coefficient. figure 7 shows the time dependent drag coefficient versus reynolds number comparing with the theoretical results were given by kendoush, for time constant τ =1,and 10. the figure shows that the drag coefficient values obtained with τ =1 is bigger than that obtained when τ =10, and the present model results are bigger than that obtained by kendoush for all reynolds values tested , but a good agreement is achieved generally. conclusions besides the hypothesis of the non-viscous external flow, all the results presented in figures 2-4 seem to be acceptable, due to the buoyancy effect, the drag coefficient decreases with time for all values of the acceleration non-dimensional parameters. the bubble growth rate, nusselt number and the time and height required to predict the drag coefficient depend mainly on the acceleration parameter, dimensionless time, froude, peclet and jakob numbers. the parametric studies presented here help in the prediction of the bubble growing in a convective surrounding (uniformly superheated pure liquids). a good agreement is achieved between the present model results of drag coefficient and kendoush’s results for acceleration .the error between present work and kendoush’s results is within ± 8.80 % for τ=1 and within ± 5.4 % for τ=10 the present results need more validity, by developing an experimental work. references askovic r. on an evaluation of the drag force of a growing vapor bubble at rectilinear accelerated ascension, theoretical and applied mechanics, vol. 27, pp. 103-116, 2002. batchelor g. k., an introduction to fluid dynamics, cambridge univ. press, cambridge (1970). battya p., v.r. raghavan and k.n. seetharamu, parametric studies on direct contact evaporation of a drop in an immiscible liquid, heat mass transfer, 27 (1984) 263–272. birkhoff g., r.s. margulies and w.a. horning, spherical bubble growth. physics fluids 1 (3), (1958), p. 201. boussinesque m. j., calcu du pouvoir refroidissant des courants fluids. j. of mathematics, vol. 70, (1905), p. 285. parametric study on a prediction the drag coefficient for a single growing bubble in uniformly superheated pure liquids al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 320 brauer h.and d. sucker, flow about plates, cylinders and spheres, international chemical engineering, 18, [3], 367–374 (1978); chemie-ingenieur-technik, 48, [8], 665–671 (1976). clift r., j. r. grace, and m. e. weber, bubbles, drops, and particles, pp. 111– 112, academic press (1978). christian k. and peter s., numerical simulation of the transient heat transfer during nucleate boiling of refrigerant hfe-7100, international journal of refrigeration 33 (2010) 1221 – 1228. dominique legendre, jacques bore´ e, and jacques magnaudet, thermal and dynamic evolution of a spherical bubble moving steadily in a superheated or subcooled liquid, , int. j. phys. fluids, vol. 10, no. 6, june (1998) 1256-1272. g. hetsroni et al., bubble growth in saturated pool boiling in water and surfactant solution, international journal of multiphase flow 32 (2006) 159–182 kendoush, a.a.(2005), the drag force on a growing bubble, the 11th international topical meeting on nuclear reactor thermal – hydraulics (nureth -11), popes' place conference center, avignon, france, october 2-6. koichi asano ,mass transfer. from fundamentals to modern industrial applications. wileyvch, 2006. lapple c. e. and c. b. shepherd, calculation of particle trajectories, industrial engineering chemistry, 32, [5], 605–617 (1940). levich v.g., physico-chemical hydrodynamics [in russian], fizmatgiz, moscow (1959). lien y., bubble growth rates at reduced pressure. sc. d. thesis, mech. eng. dept., m.i.t., (1969). mokhtarzadeh m.r and a.a. ei-shirbini, dynamics of two-phase bubble-droplets in immiscible liquids, warme-und stoffubertragung. , 19 (1985) 53-59. plesset m. s. and s.a. zwick, the growth of vapor bubble in superheated liquids. j. appl. physics 25 (4), (1954), p. 493. rayleigh l., pressure due to collapse of bubbles. phil. mag. 94, (1917). ruckenstein e., on heat transfer between vapor bubble in motion and the boiling liquid from which they are generated. chemical eng. science, vol. 10, (1959), p. 22. sideman s. and y. taitel, direct-contact heat transfer with change of phase: evaporation of drops in an immiscible liquid medium, int. j. heat mass transfer, 7 (1964) 1273-1289 stewartson k., the theory of unsteady laminar boundary layers. advanced in applied mechanics, vol. 6, academic press, new york, (1960), p. 1. ali shakir baqir 321 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 figure 2 drag coefficient cd vs. dimensionless time τ for various parametric studies pe, fr and ja parametric study on a prediction the drag coefficient for a single growing bubble in uniformly superheated pure liquids al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 322 figure 3 drag coefficient cd vs. dimensionless time τ for various parametric studies pe, fr and ja figure 4 drag coefficient cd vs. dimensionless time τ for various parametric studies pe, fr and ja ali shakir baqir 323 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 figure 5 drag coefficient cd vs. dimensionless time τ for various parametric studies re, fr and ja with different pr figure 6 drag coefficient cd vs. dimensionless time τ for various parametric studies pe and fr with different ja parametric study on a prediction the drag coefficient for a single growing bubble in uniformly superheated pure liquids al-qadisiya journal for engineering sciences, vol. 5, no. 3, 314-324, year 2012 324 figure 7 comparison between the present solution of drag coefficient cd vs. reynolds number for various non-dimensional time τ =1 and 10 and various acceleration g (2, 16) and comparison the present work with analytical solution of (kendoush, 2005) \(microsoft word 3 \\314\\344\\307\\344\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 27 effect of buckling loads on monopanel column specimens jenan nea′mah yasser al-musawi assit. lecturer /civil department / engineering college/ kufa university abstract a monopanel system is a new building material system of ferrocement that consists of two thin ferrocement block-like faces and thick layer of low strength, density and cost polystyrene foam insulation between them as a core. the simple structure idealization of monopanel system is that the core provides shear transfer between the faces that provide flexural resistance. transverse trusses made of steel bars having diameter of (3.5) mm which serve as tie reinforcement to prevent the thin ferrocement layer from local buckling, have been used in this research and they are connected by inclined steel bar forming trusses shape making an angle equal to 60° with the longitudinal bars. the core material can be made of low cost materials such as aerated concrete, expanded polystyrene concrete, polystyrene foam, which is used in the present research work. monopanel systems can be constructed on site or produced as precast units with very accurate and controlled dimensions. they can be used as walls, slabs, beams, columns and other types of similar construction. such panels should therefore offer an excellent structural system not only for low cost housing but also for low-rise buildings (up to three stories) such as residential units. the main object of this research is to present an experimental investigation on the behavior and load carrying capacity of monopanel columns. the experimental work includes testing nine monopanel columns, and has been investigated the effect of a different depths of monopanel columns on the behavior and the ultimate load capacity. also comparisons of these results with the aci-318m-08 code formulations have been made. keywords: columns, ferro cement, monopanel, buckling المونوبنل مدةعلى نماذج أعنبعاج االتأثير قوى جنان نعمة الموسوي جامعة الكوفة/ كلية الهندسة / قسم الهندسة المدنية / مساعد مدرس الموجز المونوبنل هو نوع من البناء الجديد الذي يتكون من طبقتين رقيقتين من الفيروسمنت تتخللهما طبقة نظام سميكة من مواد عازلة ذات مقاومة وكثافة قليلتين وترتبط هاتين الطبقتين بواسطة عوارض مشبكة جملونيا أخرى تميل بزاوية مقدارها تربطهما ٢ملم على هيئة قضبان طولية عدد ٣.٥مصنوعة من قضبان حديدية بقطر هذه القضبان المائلة تقوم بمقاومة قوى القص المتولدة بين الوجهين من جراء ،درجة مع القضبان الطولية ٦٠ إن المادة التي تستعمل في لب المونوبنل ذات .حماللألتسليط األحمال على أوجه وحدة المونوبنل المعرضة al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 28 ) الفلين(ار السمنت أو من خرسانة البولي ستارين أو رغوة البولي ستارينكلفة قليلة وهذه المادة قد تكون من غب .التي استخدمت في هذا البحث يمكن صناعة المونوبنل في موقع العمل أو يكون مسبق الصب ويمكن السيطرة على مواصفاته و أبعاده هذا النظام ال . كذلك كعتباتة و عمديمكن استخدام المونوبنل كجدران وبالطات وأ. بسهولة في كال الحالتين يختص باألبنية واطئة الكلفة فقط حيث يمكن تشييد األبنية لغاية ثالث طوابق مثل الوحدات السكنية والمدارس .والمكاتب ومثيالتها من الفنادق المصنعة في المختبر بموجب نظام عمدةلقد تناول هذا البحث دراسة سلوك والتحمل األقصى لأل لتسعة نماذج ألعمدة المونوبنل تمت دراسسة تأثير أحمال الفشل ومن خالل التجارب العملية . المونوبنل هذه المتغيرات على السلوك والحمل األقصى للنماذج كذلك أظهرت تمت دراسةبأختالف عمق االعمدة حيث حساب القوىل aci-318m-08من دليل الخرسانة االمريكي النتائج انه باإلمكان استخدام عالقات مدونة .لعتبات المونوبنل بشكل أمين introduction construction materials have a vast concerning of the engineering within the end of the 19th century and were developed quickly within the passed years. this development considers the cost, construction time and safety to product the ideal construction materials; the monopanel system is one of solutions. a monopanel system is a new building type having a lightweight and a low cost with respect to alternative systems. this system has an isolation core made of polystyrene foam and contains trusses shape, called lacing made of steel bars having diameter of 3.5mm making an angle equals to 60o with the longitudinal skeletal bars, which is usually made of the same material. this lacing system resists the shear effects. the core material can be made of aerated concrete, expanded polystyrene concrete, polyurethane foam, no fines concrete, polystyrene foam, etc. the density of polystyrene foam is very low equals 16 kg /m3. this low density and porous structure give the core excellent thermal and sound insulation properties. also the monopanel system can be made in site or precast to very accurate and controlled dimensions. expanded polystyrene concrete is one type of lightweight concrete which consists of expanded polystyrene beads used as aggregate and portland cement as binding material. expanded polystyrene is made by polymerizing styrene to form small beads with spherical shape (١) with a very low bulk density ranging from 12 to 18 kg/m3 and very low water absorption. these properties of polystyrene beads are considered as disadvantages in concrete, causing difficulties in mixing by floating and segregation. a number of investigators studied the properties of polystyrene concrete. (al-shawaf(3), 1987) showed that the compressive strength of polystyrene concrete increases as the density is increased and the porosity of the expanded polystyrene concrete increases with the increase of polystyrene content as well as the water absorption which indicates the open void — content of the concrete due to polystyrene addition. he found a relationship between the dry density and water-cement ratio for expanded polystyrene concrete which shows that an increase in the water– cement ratio causes a significant decrease in density. (fauzzi(5), 1997), reported that the density of lightweight concrete decreases when the expanded beads to cement ratio is increased, so by using various expanded polystyrene beads to cement ratios, lightweight concrete with densities ranging from 350 to 580 kg/m3can be obtained. she also concluded that the compressive strength, flexural strength, modulus of elasticity and poisson΄s ratio are directly proportional to the density and water cement ratio. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 29 several investigations were carried out on the behavior and strength of ferrocement members. the most notable studies can briefly be summarized as follows: (kalita,et al.(6),1986) presented a work to study the behavior of w-shape ferrocement folded plate units. the folded plate specimens were designed for an effective width of 640 mm longitudinal and cross bars were 90 mm and 300 mm respectively, with two layers of galvanized wire mesh hexagonal opening, one on either side of the skeletal reinforcement. the folded plate roofing element was tested over an effective span of 3250 mm and subjected to a uniformly distributed load by placing burnt clay bricks in layers. the amount of loading to produce a maximum allowable deflection was found to be equal to 1.47kn/m2. (mansur,et al.(7), 2001) studied the punching shear strength of simply supported ferrocement slabs. the study represented the results of punching shear tests on 31 square ferrocement slabs were it is simply supported on all four sides and tested under a central concentrated load. the parameters investigated included the width square loaded area, mortar strength, volume fraction of reinforcement, and depth of slab and the effective span length. all slabs failed first in punching without total separation, and then exhibited a second peak in the loaddeflection history. both the cracking load and the punching shear load are increased with the increase in the width of square loaded area, mortar strength, volume fraction of reinforcement, and depth of slab. the perimeter for punching shear failure was found to be located at a distance of 1.5h (where h is the thickness of slab) from the edge of the loading plate. (ravindrarajah et al. (9, 10), 1997 and 2003) concluded that partial replacement of normal weight coarse aggregate with polystyrene aggregate reduces the unit weight, compressive strength and modulus of elasticity depending on the level of replacement, the compressive strength is more sensitive to the change in the unit weight than the modulus of elasticity. they also showed that concrete mixture with the largest amount of polystyrene beads produces a peak temperature of 85.6oc compared to 70.6oc for the control concrete mixture. experimental work this section presents the materials used for constructing the monopanel column and describes the method adopted in the preparation and testing of the monopanel structural elements. it also includes details of the testing procedures. materials 1-cement: ordinary portland cement type (i) manufactured in iraq designated as kufa was used throughout this investigation. it was stored in air-tight plastic containers to avoid the effect of dampness and to maintain uniform quality. the percentage oxide composition and physical properties of the cement are shown in table 1 and table 2 respectively. the results conform to the iraqi specification no. 5/1984. 2fine aggregate: natural sand with maximum size of 2.36 mm was used in this investigation. it was brought from al-najaf region. the sand is separated by sieving; its grading satisfies the fine grading in accordance with b.s. specification no.882/1992 and the iraqi specification no.45/1984. results indicate that the sulfate content and the fine materials content are within t h e requirements of the iraqi specification no.45/1984. tables 3 and 4 show the properties of fine aggregate used in the present research work. 3-reinforcement: locally available mild galvanized steel welded wire meshes of 12.0 mm square opening with a diameter 0.6 mm have been used throughout the experimental work. and smooth mild steel bar with of 3.5mm was used for the lacing and skeletal reinforcement. table 5 shows the physical properties of reinforcement. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 30 4-polystyrene foam: polystyrene foam with low density of (16 kg / m3) was used as a core filling material. 5-water: ordinary tap water was used throughout this investigation for mixing and curing test specimens. mixing and control specimens the mixing process of mortar was performed in a pan type mixer. the specified dry materials (cement and sand) were well mixed to attain uniform mixing. the required amount of tap water was then added and the whole mix ingredients were mixed for 3-minutes. one type of mix proportion was considered throughout the research. the sand and cement were thoroughly mixed in a ratio of one part by weight of cement to two and half parts of sand (1: 2.5). the water cement ratio used to maintain a slump of (100±5 mm) was 0.5. to establish the mortar mechanical properties shown in table 6, a number of control specimens were cast and tested, three cylinders of 100 x 200 mm, three cubes of 50 x 50 x 50 mm and three cylinders of 150 x 300 mm were used to estimate the compressive strength, the modulus of elasticity and the split tensile strength. three prisms of 100 x 100 x 400 mm have been used to estimate the modulus of rapture. these tests were in accordance with the british standard bs.1881 and the american standards astm-c39, astm-c109, astm-c469 and astm-c78. results of monopanel columns tests the experimental work of the nine monopanel columns was divided into three groups (i, ii and iii). table 7 shows the column specimen details of groups i, ii and iii. also figure 1 shows the geometry of groups i, ii and iii of monopanel column specimens. the experimental results included the measured failure loads, the buckling (lateral deflection) at the center of height of column. all monopanel columns were tested under a compression force applied at a centre of column face up to failure. table 8 gives the details of the ultimate loads of each monopanel column groups. the ratios of aci-code 318 m-08 ultimate load to the value of experimental ultimate loads are listed in table 8 too. according to the experimental results, when the depth to width ratio is increased from 1 in group i to 3 in group ii , the ultimate load increases by amount 1.11 of the load in group i , and the buckling at the center of height of column at ultimate load decreases by 13.02 percent. also when the depth to width ratio increased from 1(in group i) to 4 (in group iii), the ultimate load increases by amount 1.67 of the load in group i, and the buckling at ultimate load decreases by 21.3 percent. while, when the depth to width ratio of specimen is increased from 3 to 4, the ultimate load increases by amount 0.263 of the load in group ii, and the buckling at the center at ultimate load decreases by 9.52 percent. figures 2, 3 and 4 show the load –central buckling behavior obtained at different loading stages for monopanel column specimens. figure 5 presents the crack pattern for monopanel column specimens and the loading testing machine. conclusions the conclusions emerged from the experimental work are summarized as following: 1-experimental results of testing monopanel column specimens reveal that they are acceptable structural elements for rushed construction processes, and they may safely be used to construct small housing units and small structures. 2the failure load increased by increasing the depth dimension of monopanel column, as the depth to width ratio increasing from 1 to 3 the ultimate load increased by 111 percent. also the ultimate load increased by 167 percent as the depth to width ratio increasing from 1 to 4. while, when the depth to width ratio increased from 3 to 4, the ultimate load increased by 26.3 percent. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 31 3the experimental results show that when the depth of specimen increases in a ratio from 1 to 3, the buckling at ultimate stage decreases by 13.02 percent. in addition, when the depth of a specimen increases in a ratio from 1 to 4 the buckling (at ultimate stage) decreases 21.3 percent. while, when the depth of specimen increases in a ratio from 3 to 4, the buckling at ultimate stage decreases by 9.52 percent. hence by increasing the depth of monopanel column specimen, the buckling at the center of height decreased. 4it can be noticed that the ratio between the theoretical to the experimental ultimate load is (0.3) compared with the aci-code 318 m-08 provisions requirements. area of steel for columns of group i is (9.8mm2), for group ii is (23.7mm2), and for group iii is (31.1mm2). the gross area for columns, properties of reinforcement and the mechanical properties of mortar mix is the same as for monopanel column specimens. references [1]acijournal, “guide for cast-inplace low-density concrete”, vol.83, no.5, 1986, pp.830837. [2]al-shawaf, a.k., “dynamic properties of lightweight ferrocement plates”, m.sc. thesis, university of baghdad, 1987. [3]castro, j. “app1ication of ferrocement, in low-cost. housing in mexico” ferrocement materials and applications, american concrete institute, publication, sp-61, pp.143-156, 1979. [4]fauzzi, n. m., “properties of lightweight concrete with a view to thermal insulation and acoustic impedance,” m. sc. thesis, university of baghdad, 1997. [5]kalita, u.c.m., nambiar, k.c., borthakur, b.c., and baruah, p., “ferrocement roof for low cost housing”, indian concrete journal, july, 1986. [6]mansure, m.a., ahmed, i., and paramasivam, p., “punching shear strength of simply supported ferrocement slabs”, journal of materials in civil engineering, november-december 2001, pp.418426. [7]ravindrarajah, r.s., and sabaa, b., “engineering properties of lightweight concrete containing crushed expanded polystyrene wastes”, symposium: advances in materials for cementitious composites, dcc.1-3, 1997, boston, usa. [8]ravindrarajah, r.s., “properties of adjusted density highperformance concrete”, advanced in structures: steel, concrete, composite and aluminum (asscca) 03 conference, sydney, australia, june 2003. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 32 table 1 percentage oxide composition* and compounds of cement used in this investigation. oxide composition percentage, by weight limit of iraqi specification no. 5/1984 cao 61.2 ---- sio2 21.87 ---- mgo 2.6 5.0 (max) fe2o3 3.04 ---- al2o3 5.8 ---- so3 2.21 2.80 (max) loss on ignition 1.5 4.0 (max) insoluble residue 1.1 1.5 (max) lime saturation factor 0.85 0.66-1.02 main compounds percentage, by weight limit of iraqi specification no. 5/1984 c3s 53.65 ---- c2s 18.73 ---- c3a 9.33 5.0 (min) c4af 10.12 ---- table 2 physical properties of the cement used in this work* physical property test result limit of iraqi specification no. 5/1984 specific surface area (blaine method), m2/kg 322 230 (minimum) setting time (vicat’s method) initial setting, hrs: min final setting, hrs : min 2:15 4:35 1 hr (minimum) 10:00 hr(maximum) compressive strength of mortar, n/mm2 3-days 7-days 19.5 28.45 15.0 (minimum) 23.0 (minimum) autoclave expansion, % 0.23 0.8 (maximum) * chemical and physical tests were conducted by national center for construction laboratories and research (ncclr). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 33 table 3 grading of natural sand used in this research. sieve size (mm) cumulative of tested sand passing % limits of b.s.882:1992 overall grading limits of iraqi specification no.45/1984 f o r zone no. ( 3 ) 9 . 5 2 1 0 0 1 0 0 1 0 0 4 . 7 5 98.7 8 9 1 0 0 9 0 1 0 0 2 . 3 6 92 6 0 1 0 0 8 5 1 0 0 1 . 1 8 88 3 0 1 0 0 7 5 1 0 0 0 . 6 0 0 78.3 1 5 1 0 0 6 0 7 9 0 . 3 0 0 28.6 5 7 0 1 2 4 0 0 . 1 5 0 5 0 1 5 0 1 0 table 4 physical properties of fine sand used in this study. physical properties test results limits of iraqi specification no.45/1984 specific gravity 2.61 sulfate content, % 0.4 ≤ 0.5 % absorption, % 1.5 materials finer than75µ m, % 2.8 ≤ 5% table 5 properties of reinforcement. measured diameter (mm) modulus of elasticity e (mpa) yield stress fy (mpa) ultimate stress fu (mpa) 0.6 175000 350 580 3.5 200000 400 690 table 6 mechanical properties of mortar mix (average of three specimens). mix proportion (cement-sand) compressive strength (mpa) splitting strength (mpa) modulus of rupture (mpa) modulus of elasticity (mpa) f'c fcu fct fr em 1:2.5 20.3 26.6 2.12 2.71 22646 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 34 table 7 details of groups i, ii and iii of monopanel column specimens group depth d(mm) width w(mm) height h(mm) face thickness t(mm) no. of lacing(ties) core depth(mm) i 150 150 900 25 5 130 ii 450 150 900 25 5 430 iii 600 150 900 25 5 580 table 8 ultimate loads for monopanel column specimens group d experemental ultimate load (kn) ultimate load (kn) according to aci-code 318 m-08 paci pexp. i 150 9 2.82 0.314 ii 450 19 6.56 0.345 iii 600 24 8.521 0.355 figure 1 geometry and reinforcement details of monopanel column specimens used for groups i, ii and iii. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 35 figure 2 buckling at center of height of monopanel column with d=150 mm. figure 3 buckling at center of height of monopanel column with d=450 mm. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 36 figure 4 buckling at center of height of monopanel column with d=600 mm. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 37 figure 5 buckling crack pattern for monopanel column specimens and the loading testing machine. improvement of the mechanical properties of gypseous soil by additives al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٧ improvement of the mechanical properties of gypseous soil by additives huda n. t. al-numani civil engineering university of kufa abstract the presence of gypsum in soil as bond agent alters its behavior, in other words, there is a large influence of gypsum on the physical and mechanical properties of soil. this influence depends mainly on the amount and type of gypsum presented in the soil. the soils used in this study were brought from one locations at al-tar region west of al-najaf city. these soils had gypsum content of 35%. the classification tests indicate that the soil is poorly graded. in this paper an experimental study is carried out on the effect of three different additives to the gypseous soil in order to improve the compaction properties of the gypsum soil. the additives used in this study were cement, ceramic and mix of cement and ceramic. the percentages of ceramic was varied between 4-12% in the first series whereas percentage of cement was between 48% by weight in the second series. in the third series the percentage of cement was kept constant 4% by weight while the percentage of ceramic varied from 4 to 12% by weight. control groub without any additive was also tested to determine the effect of additives. the results show that the best improvement in compaction characteristics test is achieved when the sample is treated with adding mix of cement and ceramic, the maximum dry density only increase with the increases in mixing content, while the opposite is true for the optimum water content. the results also show that the maximum dry density of treated gypsum soil with ceramic material increases with the increase in ceramic content up to 8% after which the density decreases. key words: soil, gypsum, ceramic, cement, compaction إضافاتالجبسیه بواسطة للتربةالمیكانیكیةسین الخواص تح هدى ناجح طاهر جامعة الكوفةالهندسةكلیة الخالصة هنــــاك تــــأثیر كبیـــر للجــــبس علـــى الخــــواص الفیزیائیــــة ، بتعبیــــر أخـــر، یغیــــر ســـلوكهاكعامـــل ربــــطوجـــود الجــــبس فـــي التربــــة الدراسـةلتربـة المسـتخدمة فـي هـذه .میـة ونـوع الجـبس الموجـود فـي التربـةیعتمد هذا التـأثیر بشـكل رئیسـي علـى ك. والمیكانیكیة للتربة اختبــار أشــار%). ٣٥(ذات محتــوى جبســي التربــةكانــت.الطــار الواقعــة غــرب مدینــة النجــفمــن موقــع واحــد مــن منطقــةأخــذت ة إلــى التربــة إضــافات مختلفــدراســة تجریبیــة علــى تــأثیر ثــالث فــي هــذا البحــث أجریــت.التربــة رملیــه ضــعیفة التــدرجالتصــنیف بــأن توخلـیط األسـمنتاألسـمن، اإلضافات المستعملة في هذه الدراسة هي الخزف . سیه للتربة الجبالرصخواصالجبسیه لكي تحسن %) ٨-٤(كانـت بـین تفي السلسلة األولـى بینمـا نسـبة األسـمن%) ١٢-٤(النسب المئویة لمادة الخزف كانت تتفاوت بین . والخزف -٤(بــین تتــراوح نســبة الســیرامیكبینمــا%) ٤(ثابتــة تفــي السلســلة الثالثــة كانــت نســبة األســمن. تربــة فــي السلســلة الثانیــةمــن وزن ال al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٨ ي بینـت النتـائج بـأن أفضـل تحسـین فـ.كذلك فحصت التربة بدون أي إضافات إلیجاد تـأثیر هـذه اإلضـافات. من وزن التربة%) ١٢ حیــث وجــد أن الكثافــة الجافــة العظمــى تــزداد بزیــادة ، والخــزفتافة خلــیط األســمنبإضــتعــالج العینــةینجــز عنــدماخصــائص الــرص بینـت النتـائج أن الكثافـة الجافـة العظمـى للتربـة الجبسـیه المعالجـة بمـادة . بینما العكس صحیح لمحتوى الماء األمثـل، محتوى الخلیط .تتناقص الكثافةبعدها% ٨الخزف تزداد بزیادة محتوى الخزف إلى حد list of abbreviations and notations abbreviations meaning astm american society for testing and materials a ceramic content by weight (%) bs british standard c cement content by weight (%) eo initial void ratio sp poorly graded sand  gypsum content (%) introduction gypsiferous soils usually stiff when they are dry, but these soils may be affected greatly when subjected to changes in water content due to water table fluctuation, or due to water infiltration which may dissolve gypsum causing pores, crack and producing cavities that lead to increase the permeability in gypseous soils. therefore, the safety and good performance of the foundation of structures and earth structures such as embankments and dams will be governed by the changes in the properties of these soils. gypsiferous soils occupy about 100 million ha (one million km2) in the world across algeria, argentina, australia, iraq, libya, somalia, spain, sudan, syria, the former ussr and other arid and semi aired countries with annual rainfall of less than (500)mm (fao, 1990). compaction is the improvement of the engineering properties of the soil mass which occurs through increasing strength, reducing compressibility, volume change and permeability, and increasing the stability of structures (lambe and whitman, 1979, holtz and kovacs, 1981) kattab (1986) reported that the maximum dry density for treated and untreated granular soils increases with the increase in gypsum content up to (15%) after which the density decreases. subhi (1987) found, for compacted soil, that the maximum dry density only decreases with the increase in gypsum content, whereas the optimum moisture content increases or decreases according to the size of the added gypsum grains. the work of al-heeti (1990) on compacted gypsified silty clay showed a different behavior. the maximum dry density increases as the gypsum content increases, while for another silty clay, originally gypseous soil, the maximum dry density decreases as the gypsum content increases and after a certain value it starts to increase again. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٩ al-layla and al-obaydi (1993) showed that for high gypseous soils, the maximum dry density is slightly affected by the change in gypsum content, while the optimum water content decreases with the increase in gypsum content. al-obaydi (1999) noticed that using the standard and modified compactive effort, the maximum dry density increase with the gypsum content, due to the more gypsum occupying the voids and the optimum water content decreases slightly. also, the maximum dry density increases by about (12%) when the compactive effort increases from standard to modified, while the average reduction in the optimum water content is about (15%). al-gabri (2003) showed that the optimum moisture content decreases and maximum dry density increases with the increase of gypsum content. the purpose of the study the purpose of this study is to investigate the effect of three different additives (ceramic, cement and mix cement and ceramic) to the gypseous soil on compaction properties. laboratory testing program the testing program in this work can be summarized in the following groups:  classification tests are performed firstly including physical and chemical tests. the physical tests include specific gravity, atterberg limits, grain size distribution and water content.  standard proctor compaction tests are carried out to determine the moisture-density relationship for the virgin soil and for treated soil by three addition (cement, ceramic and mix cement and ceramic) as follows:  group one: the soil is tested in the natural case (untreated soil).  group two: in treated case with 1ceramic (three various percents are used 4, 8 and 12% by weight of soil). 2cement ((three various percents are used 4, 6 and 8% by weight of soil). 3mix cement and ceramic (the percentage of cement was kept constant 4% by weight while the percentage of ceramic varied from 4 to 12% by weight). classification tests physical tests specific gravity: the specific gravity of the soil is determined according to the british standards (bs 1377: 1975, test no.6 (b), head 1980), but kerosene is used instead of water due to the dissolution of gypsum in water. atterberg limits: liquid limit test is carried out in accordance with (bs 1377: 1975, test 2(a)), using cone penetrometer method. the plastic limit is determined in accordance with (bs 1377: 1975, test no. 3). the liquid and plastic limits are carried out on soil passing sieve (no.40) and the temperature used for drying is maintained at (45–50)°c due to the presence of gypsum in the soil, (astm 221680). grain size distribution: the grain size distribution is determined by sieve analysis test, which is conducted in accordance with (astm d922-72) with dry sieving. water content al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٠ this is performed in accordance with (bs 1377: 1975, test (a), head 1980). the water content is determined at drying temperature of (45)°c because the soil contains a significant amount of gypsum, to avoid the loss of crystal water is required. chemical tests  total soluble salts (tss)% are determined accordance to the (bs 1377: 1975, test (9)).  the gypsum content is found according to the method presented by nashat and al-mufty, (2000). this method consists of oven drying the soil at (45°c) until the weight of the sample becomes constant. the weight of sample at (45°c) is recorded. then, the same sample is dried at (110°c) until the weight becomes constant and recorded. the gypsum content is calculated according to the following equation:  (%) = [(w45°c w110°c) / w45°c] x 4.778 x 100 where:  = gypsum content (%) w45°c = weight of the sample at (45°c) w110°c = weight of the sample at (110°c) compaction tests standard compaction tests are carried out for the untreated and treated soils to determine the moisture-unit weight relationship according to (astm d 698, method a, 2003). a mold of (101.6) mm in diameter and height of (115.5)mm is used. samples are compacted in three equal layers each hammered by (25) blows using (2.5) kg hammer dropped from (30.5)mm height. testing material the soil samples used in this study were brought from one location at al-tar region west of al-najaf city. the soil samples are obtained from a depth of (2.0)m below the natural ground surface. the samples are packed in double nylon bags and transported to the soil mechanics laboratory at al-kufa university for testing. ceramic materials are used in this study to modify mechanical properties for gypseous soil. ceramics are classified inorganic and nonmetallic materials. they are generally made by taking mixtures of clay, earthen elements, powders and water and shaping them into desired forms then it is fired in a high temperature oven. often, ceramics are covered by decorative, waterproof, paintlike substances knowing as glazes. the ceramic materials are mixed with gypseous soil passing through sieve no.4. the results of physical and chemical tests are summarized in table (1). the cement material is used in this study to modify the soil. all kinds of cement are good to modify the soil, but most familiar kind in usage is the portland cement. it helps to increase soil resistance, its endurance, durability and at the same time it decreases humidity variegation. results and discussion the soil specimens can be classified according to the unified soil classification system (uscs), as poorly graded sand (sp). the result of atterberg limit test indicate that the sample is non-plastic. the results of standard compaction test for the natural gypsum soil (without additives) are tabulated in table (1). the relationship between dry density and water content for the tested soil is shown in figure (1), while figures (2) to (4) show the relationship for samples tested after treatment with the three additives. in figure (5), the three additives content is plotted versus maximum dry unit weight in normal scale. it was found that the maximum dry density increases with increasing ceramic content up to 8% after which the maximum dry density decreases. it can be also noticed that, for soil samples al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩١ treated with cement and mix cement and ceramic the maximum dry density increases with increasing additives content. a summary of data is given in table (2). in figure (6), the change in optimum water content is plotted versus the additives content which indicates that the optimum water content increases or decreases with increasing ceramic content, while it increases with increase in cement content. it can be also noticed that the optimum water content increases up to 4% after which the optimum water content decreases. conclusion 1. the best improvement in maximum dry unit weight is achieved when the samples are treated with mix cement and ceramic. 2. the maximum dry unit weight increases with increasing ceramic content up to 8% after which the maximum dry unit weight decreases. 3. no apparent behavior can be concluded from the behavior of samples treated by ceramic material, especially for the optimum water content. 4. as the cement content increases, the optimum water content increases from 17.1 to 19.6%. 5. adding waste of ceramic material may add extra cost but the overall cost of the mix may become economical. however, it requires further research to study the mix from economical point of view. references -al-gabri, m.k.a., (2003), “collapsibility of gypseous soils using three different methods”, m.sc. thesis, building and construction engineering department, university of technology, baghdad. -al-heeti, a.a.h., (1990), “the engineering properties of compacted gypsified soil”, m.sc. thesis, civil engineering department, university of baghdad. -al-layla, m.t., and al-obaydi, m.a., (1993), “lime stabilization of gypseous soil”, proceedings of the 5th arab conference of structural engineering, vol. 2, civil engineering department, al-fateh university, tripoli, p.p. 1001-10130 -al-mufty, a.a. and nashat, e.h., (2000), “gypsum content determination in gypseous soils and rocks”, proceedings of the 3th jordanian international mining conference, amman, vol. 2, p.p. 485-492. -al-obaydi, m.a., (1999), “effect of moisture content on shear strength parameters of gypseous soils”, scientific journal of tikrit university, engineering, vol. 6, no. 2, p.p. 60-72 -astm standers (2003), “soil and rock (i) ”, volume 04.08. -british standard institution bs 1377 (1975), “method of testing soil for civil engineering purposes”, london. -fao, (1990), “management of gypsiferous soils”, fao soils bulletin, no.62. -head, k.h., (1980), “manual of soil laboratory testing”, vol. 1, prentch, press, london. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٢ -kattab, s.a., (1986), “effect of gypsum content on strength of granular soils for soaked and unsoaked specimens”, m.sc. thesis, civil engineering department, university of mosul -holtz, r.d., and kovacs, w.d., (1981), “an introduction to geotechnical engineering”, printicehall, inc., englewood cliffs, new jersey. -lambe, t.w., and whitman, r.v., (1979), “soil mechanics”, john wiley and sons, inc., new york. -subhi, r.k., (1987), “properties of salt contaminated soils and their influence the performance of roads in iraq”, ph.d. thesis, queen mary college, university of london. table ( 1 ): summary of physical and chemical tests. table ( 2 ): result of compaction tests after treatment. soil property soil gypsum content (%) 35 total soluble salts (%) 8 specific gravity (gs) 2.61 initial void ratio (eo) 0.54 initial water content (%) 0.49 maximum dry unit weight (kn/m3) 18.2 optimum water content (%) 15.9 soil classification according to (uscs) sp soil property ceramic % cement % cement % +ceramic % a=4 a=8 a=12 c=4 c=6 c=8 4+4 4+8 4+12 maximum dry unit weight, kn/m3 19.1 19.5 18.6 19.7 20.3 20.8 20.8 21.3 21.8 optimum water content, (%) 16.3 13.5 15.7 17.1 19.4 19.6 17.7 16.1 14.6 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٣ 0 5 10 15 20 25 watercontent(%) 16 17 18 19 d ry u ni tw ei gh t, kn /m 3 figure (1): standard compaction curve for untreated soil. 0 5 10 15 20 25 watercontent (%) 17 18 19 20 d ry un it w ei gh t, kn /m 3 a=4% a=8% a=12% figure (2): standard compaction curves for soil treated with ceramic. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٤ figure (3): standard compaction curves for soil treated with cement. 0 5 10 15 20 25 watercontent (%) 18 19 20 21 22 23 d ry un it w ei gh t, kn /m 3 c=4%+a=4% c=4%+a=8% c=4%+a=12% figure (4): standard compaction curves for soil treated with (cement and ceramic). 0 5 10 15 20 25 watercontent (%) 17 18 19 20 21 d ry un it w ei gh t, kn /m 3 c=4% c=6% c=8% al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٥ 0 4 8 12 16 ceramiccontent(%) 18.0 18.5 19.0 19.5 20.0 m ax m um d ry d en si ty ,k n /m 3 ( a ) 0 4 8 12 cementcontent(%) 18 19 20 21 m ax im um d ry d en si ty ,k n /m 3 ( b ) 0 4 8 12 16 (cement+ceramic)content(%) 18 19 20 21 22 m ax im um d ry d en si ty ,k n /m 3 ( c ) figure (5):effect of additives on maximum dry density. (a) ceramic, (b) cement, (c) cement and ceramic. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٦ 0 4 8 12 16 ceramiccontent(%) 13 14 15 16 17 o pt im um w at er c on te nt (% ) ( a ) 0 4 8 12 cementcontent(%) 15 16 17 18 19 20 o pt im um w at er c on te nt (% ) ( b ) 0 4 8 12 16 (cement+ceramic)content(%) 14 15 16 17 18 o pt im um w at er c on te nt (% ) ( c ) figure (6): effect of additives on optimum water content. (a) ceramic, (b) cement, (c) cement and ceramic al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 472 pressure drop constraints in sludge double-pipe heat exchanger design dr. amer d. zmat college of engineering, university of al-qadisiyah email: amer.zmat@qadeng.org abstract: recent years have witnessed a rapid development in the understanding of heat exchangers design. those developments have justified the use of a global minimum allowable temperature approach under which the heat transfer area of the heat exchanger is minimized. values of the allowable pressure drops of streams of exchangers are specified to calculate film heat-transfer coefficients of streams and heat-transfer area. by coupling this with the understanding of what dictates the energy consumption, it is possible to determine the trade-off between the heat exchanger capital cost and energy cost prior to design work. pressure drop is an important issue in the design of a heat exchanger. pumps and (or) compressors must be installed to overcome pressure losses when streams flow through heat exchangers. the total cost for a system of pumps and compressors consists of the purchase cost of equipments and the electricity cost to run these equipments. this cost could occupy a significant part of the overall cost for a heat exchanger. therefore, the pressure drop aspect should be considered together with the costs of heat exchanger area. this paper demonstrates how pressure drop is considered in the context of a sludge doublepipe heat exchanger design. a relationship between heat transfer coefficient and heat exchanger pressure drop was determined and its capital cost implications were assessed. keywords: heat exchanger design, pressure drop constraints, heat exchanger costs. محددات فرق الضغط في تصميم مبادالت الحمأة الحرارية نوع األنبوب المزدوج ر دحام زماطعام. د جامعة القادسية-كلية الهندسة :الخالصة تميزت معظمها باستخدامها مفهوم أدنى فرق . شهدت السنوات األخيرة تطور سريع في تصاميم المبادالت الحرارية حساب وطبقا لتلك الطريقة يتم تحديد قيم فرق الضغط المقبول ل. في درجات الحرارة للحصول على اقل مساحة انتقال حراري معامل انتقال الحرارة ومساحة االنتقال الحراري من خالل ربط هذه الطريقة مع أسلوب حساب استهالك الطاقة في المبادالت . الحرارية ويمكن إجراء المفاضلة بين كلفة المبادل الحراري وكلفة الطاقة الالزمة لتشغيله قبل مرحلة التصاميم التفصيلية دالت الحرارية ينعكس على كلف ملموسة في المبادالت الحرارية تتمثل بكلف المضخات وحيث أن فرق الضغط في المبا mailto:amer.zmat@qadeng.org al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 473 والدافعات وكلف الطاقة الالزمة لتشغيل تلك المضخات والدافعات، فان دراسة تلك الكلف نسبة إلى كلفة المبادل الحراري تعتبر .أمر ضروري ومهم ت األنبوب المزدوج المستخدم لتسخين الحمأة في أحواض يستعرض هذا البحث كيفية تضمين فرق الضغط في مبادال الهضم ضمن مرحلة التصميم من خالل إيجاد عالقة بين معامل انتقال الحرارة وفرق الضغط وتقييم انعكاس ذلك على الكلفة .المثالية للمبادل الحراري introduction: the heat transfer rate of heat exchanger streams can be improved by generating turbulent flow (breaking the viscous and thermal boundary layers), but the pumping power may increase significantly and ultimately the pumping cost becomes high. swirl flow devices for example, a twisted-tape [1-3], a wire-coil inserts, and tangential injection devices [4] impart a tangential velocity component to the fluid that increases the turbulence of the flow and consequently the heattransfer coefficient. double pipe heat exchanger is considered to be most reliable among other types of heat exchangers. it usually requires minimal maintenance. it is widely used for critical heating or cooling of slurries and high viscosity liquids. sludge is one example of those high viscosity liquids. sludge heat exchangers are used to heat sludge at inlet of anaerobic digesters. these exchangers are clog free and easy to wash from sludge encrusting. this is the result of having pipe completely straight and easy to dismantle. besides to the previous advantages (suitable for severe fouling conditions), double pipe heat exchangers suffer a shortcoming of small heat transfer area (up to 50 m2) and high pressure. the great attempt on utilizing different methods is to increase the heat transfer rate through compulsory force convection. in general, enhancing the heat transfer can be divided into two groups. one is the passive method, without stimulation by the external power such as a surface coating, rough surfaces, extended surfaces, swirl flow devices, the convoluted (twisted) tube, additives for liquid and gases. the other is the active method, which requires extra external power sources, for example, mechanical aids, surface-fluid vibration, injection and suction of the fluid, jet impingement, and use of electrostatic fields. whitham [5] published his work on heat transfer enhancement by means of twisted-tape way back at the end of the nineteenth century. koch [6] indicated that in turbulent flow, inserting of a twisted-tape increases the heat transfer, but the pressure drop also increases significantly. kumar and bharadwaj [7] obtained theoretically the heat transfer and pressure drop correlations using the kreith and sonju [8] solution for the velocity vector, which decays along the axis of the tube. huang and tsou [9] studied free swirl flow in a pipe. aydin [10] investigated heat transfer and pressure drop in a concentric heat exchanger with turbulent decaying swirl flow. liao and xing [11] reported experimental data on the compound heat transfer enhancement technique and concluded that the enhancement of heat transfer in a tube with three dimensional internal extended surfaces by replacing continuous twisted-tape with almost segmented twisted-tape inserts results in a decrease in the friction factor but with a comparatively small decrease in the stanton number. the stanton number is defined as the ratio of heat transfer rate to the enthalpy difference and is a measure of the heat transfer coefficient. in the present study, pressure drop across sludge double pipe heat exchanger has been related to heat transfer coefficient, so its cost implications on capital cost are readily assessed. therefore, it is convenient to consider the optimization of pressure drops instead of specifying fixed allowable pressure drops in the targeting stage. both inner and outer pipes of the double pipe heat exchanger were assumed to follow the dittusboelter equation. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 474 mathematical modeling: for allowable pressure drop to be considered in design optimization, a relationship between heat transfer coefficient and exchanger pressure drop was developed. the film heat transfer coefficient is given by the dittus-boelter equation: 3 1 8.0 prre023.0=nu ………….…………………………………………………. (1) where: nu : nusselt number. re : reynolds number. pr : prandtl number. 3 1 8.0 )()(023.0 k cpud k hd µ µ ρ = ………………………………………………………. (2) where: h : convective heat transfer coefficient. d : pipe diameter. ρ : fluid density. µ : fluid viscosity. cp : specific heat. k : conductive heat transfer coefficient. u : fluid flow velocity. 8.03 1 8.0 )()()(023.0 u d k k cpd h µ µ ρ = ………………………………………….………. (3) 8.067.0 2.047.0 3 1 8.0 1)(023.0 uk d cph µ ρ= ………………………….………………… (4) for average flow conditions of double pipe heat exchanger, thermal and flow properties can be assumed constants. therefore: 8.01uch = ……….………………………………….……………………………… (5) where: 67.0 2.047.0 3 1 8.0 1 1 )(023.0 k d cpc µ ρ= equation (5) clearly shows that heat transfer is directly proportional to fluid velocity raised to (0.8). c1 is a constant and its value depends on thermal and flow properties. the pressure drop through the pipe is given by the fanning equation: al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 475 2)(2 u d l fp ρ=∆ …………………………………………..……………………….. (6) where: p∆ : pressure drop. f : friction factor. l : pipe length. the friction factor is given by the blasius equation: 2.0re046.0 −=f ………………………………………...………………………….. (7) substituting equation (7) into equation (6): 22.0 )()(092.0 u d lud p ρ µ ρ −=∆ …………………………………….………………… (8) 8.12.02.18.0092.0 ludp µρ −=∆ ……….………………………………………………. (9) again for average flow conditions of double pipe heat exchanger, thermal and flow properties can be assumed constants. therefore: 8.12lucp =∆ ……………………………………………………………………… (10) where: 2.02.18.02 092.0 µρ −= dc equation (10) clearly shows that pressure drop across double pipe heat exchanger are directly proportional to the velocity of fluid raised to (1.8). this relation reflects the higher sensitivity of pressure drop to fluid velocity than the heat transfer coefficient. the velocity of fluid can be expressed in terms of its volumetric flow rate: 2 4 d v u π = …………………………………………………………………………. (11) where: v : volumetric flow rate. the heat transfer area is given by: dla π= ………………………………………………………………………….. (12) where: a: heat transfer area. multiplying equation (11) by equation (12) yields: d vl d v dlau 44 2 == π π ……………………………………………………………. (13) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 476 au v d l 4 = ………………………………………………………………………. (14) substituting for l in equation (10) from equation (14): 8.22 4 au v d cp =∆ ………………………………………………………………... (15) 8.232 auccp =∆ ………………………………………………………………... (16) where: v d c 43 = equations (16) and (5) show both pressure drop and heat transfer coefficient are functions of fluid flow velocity. from equation (5): 1 8.0 c h u = ……………………..…………………………………………………… (17) 25.1 1 25.1 c h u = …………………...………………………………….………………… (18) substituting for u from equation (18) into equation (16): 5.3 5.3 1 328.2 25.1 1 25.1 32 )( ahc cc c h accp ==∆ ………...……………………………………… (19) equation (19) shows that pressure drop across double pipe heat exchanger is related to heat transfer coefficient, so the augmentation of heat transfer coefficient through turbulence effect is directly reflected on pressure drop increase and consequently on energy consumption cost. as heat transfer coefficient increases, heat transfer area decreases and heat exchanger capital cost will be reduced accordingly. both heat transfer area and energy consumption costs were estimated using aspen correlations. both costs were directly expressed in terms of heat transfer coefficient. th q a ∆ = ………………………………………………………………………. (20) where: q : heat flow rate. t∆ : temperature difference. 5.24 ht q cp ∆ =∆ ………………………….………………………………………. (21) where: 5.3 1 32 4 c cc c = equations (20) and (21) demonstrate the dependence of both heat transfer area and pressure drop on heat transfer coefficient. it is clearly seen that heat transfer area is inversely proportional to heat transfer coefficient while pressure drop is directly proportional to it. therefore, the al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 477 augmentation of heat transfer coefficient leads to considerable reduction in heat transfer area (heat exchanger capital cost), at the same time, this augmentation will cause an increase in pressure drop across the exchanger (energy consumption cost). these costs are expressed using aspen correlations [12] as: 21 2 1 )( th q kakcc ∆ == ………………………………...………………………… (22) where: cc : heat exchanger capital cost. 1k : constant depends on material of construction. 5.23 5.2 422 ht q kh t q ckpkec ∆ = ∆ =∆= …………………….……………………. (23) where: ec : energy consumption cost of heat exchanger. 3k : constant depends on fluid properties and geometry. the main characteristics of a double pipe heat exchanger that used to heat a domestic wastewater sludge in an anaerobic digester is shown in table (1). the schematic representation of a sludge double pipe heat exchanger is shown in figure (1). a countercurrent scheme is adopted for this investigation study as shown in the figure. results and discussions: table (2) presents the dependency of heat transfer coefficient (h), heat transfer area (a) and pressure drop across sludge pipe ( ∆ p) on the sludge stream velocity. it clearly shows that the increase of heat transfer coefficient is approximately linear function of the sludge stream velocity. this increase reflects oppositely on heat transfer area and directly on pressure drop. the heat transfer area decreases linearly while the pressure drop increases in exponent behavior. table (3) shows the capital cost (cc) of the double pipe heat exchanger as a function of the heat transfer area. the cost shown in the table represents the purchase cost of the heat exchanger only. table (4) indicates the yearly pumping energy consumption cost (ec) of the sludge stream as a function of pressure drop. the table shows the steep increase in energy consumption cost as the pressure drop increases. figures (2-7) schematically demonstrate the behavior of the main parameters of heat exchanger (heat transfer coefficient, heat transfer area, pressure drop, capital cost, and pump energy cost) in relation to sludge stream velocity. figure (1) reflect the linearity of the relationship between the heat transfer coefficient and the sludge stream velocity. the little increase in heat transfer coefficient is reflected on heat transfer area as shown in figure (2) and on pressure drop in figure (3). figures (4-5) explain how capital cost drops and energy cost escalates as velocity increases. the total cost of the heat exchanger is shown in figure (6). it can be seen that the optimum cost happens to be low velocities rather than high velocities. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 478 conclusions: both heat transfer area and pressure drop across double pipe heat exchanger are related to sludge stream velocity to specify the economic stream pressure drop ahead of design. it was concluded that the reduction in heat transfer area due to velocity augmentation not necessarily determines the minimum cost of double pipe heat exchanger. it was seen that stream pressure drop dominates the cost of the heat exchanger beyond threshold stream velocity. this leads to the use of the extended heat transfer area rather than the approach of inducing turbulence to augment the heat transfer coefficient when exceed the threshold stream velocity. references: [1] date aw and saha sk, "numerical prediction of laminar flow and heat transfer in a tube fitted with regularly spaced twisted-tape elements", international journal heat fluid flow, 1990, 11, 346354. [2] hong sw and bergles ae, "augmentation of laminar flow heat transfer in tubes by means of twisted-tape inserts", international journal heat transfer, 1976, 251-256. [3] kumar a and prasad bn, "investigation of twisted tape inserted solar water heaters-heat transfer, friction factor and thermal performance results", renewable energy, 2000. 19, 379-398. [4] lepina rf and bergles ae, "heat transfer and pressure drop in tape-generated swirl flow of single-phase water", asme journal heat transfer, 1969, 91, 434-442. [5] witham, j.m., "the effects of retarders in fire tubes of steam boilers", street railway journal, vol. 12, no. 6, pp. 374. [6] koch, r. 1958, "pressure loss and heat transfer for turbulent flow", vdi-forschungsheft, vol. 24, no. 469, pp. 11-44. [7] kumar, r. and bharadwaj, r.k., 1979, "heat transfer and pressure drop in decaying swirl flow of water through a tube containing the twisted tape", journal instrument engineering (india), vol. 60 (part me2), pp. 72-77. [8] kreith, f. and sonju, o.k. 1965. the decay of a turbulent swirl flow in a pipe. journal fluid mechanics, vol. 22 (part 2), pp. 257-271. [9] huang, f. and tsou, f.k. 1979, "friction and heat transfer in turbulence free swirl flow in pipes", transaction asme, journal heat transfer, 79-ht-39, pp. 1-9. [10] aydin durmus, ayla durmus, m. esen, "investigation of heat transfer and pressure drop in a concentric heat exchanger with snail entrance", applied thermal engineering 22 (2002) 321–332. [11] liao, q. and xing, m.d., 2000, "augmentation of convective heat transfer inside tubes with three dimensional internal extended surfaces and twisted tape inserts", chemical engineering journal, vol. 78, pp. 95-105. [12] gravin p. towler, r. k. sinnot, " aspen icarustm", chemical engineering design: principles, practice and economics of plant. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 479 table (1) main characteristics of a sludge double pipe heat exchanger sludge inlet temperature 31 c0 sludge outlet temperature 39 c0 sludge flow rate 94 m3/h heat transfer rate 1129 kw heating fluid inlet temperature 65 c0 heating fluid outlet temperature 50 c0 heating fluid flow rate 50 m3/h table (2) relationship between sludge stream velocity and heat transfer coefficient, heat transfer area and pressure drop. u (m/s) h (w/m2 c) a (m2) ∆ p (n/m2) 0.5 1084.7 103 1398.3 1.0 1888.7 59.3 5608.4 1.5 2612.4 42.8 12615.2 2.0 3288.4 34 22393.8 table (3) capital cost of heat exchanger as a function of heat transfer area. a (m2) cc ($) 103 232337 59.3 77011 42.8 40117 34 25316 table (4) sludge stream pumping cost as a function of pressure drop. ∆ p (n/m2) ec ($) 1398.3 75368.4 5608.4 302292.7 12615.2 679948.5 22393.8 1207025.8 figure (1), schematic representation of a sludge double pipe heat exchanger al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 480 0 500 1000 1500 2000 2500 3000 3500 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 u (m/s) h (w /m 2 c ) figure (2) relationship between heat transfer coefficient and sludge stream velocity. 0 20 40 60 80 100 120 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 u (m/s) a (m 2) figure (3) relationship between heat transfer area and sludge stream velocity. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 481 0 5000 10000 15000 20000 25000 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 u (m/s) p (n /m 2) figure (4) relationship between pressure drop and sludge stream velocity. 0 50000 100000 150000 200000 250000 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 u (m/s) c c ($ ) figure (5) capital cost of heat exchanger decline in relation to stream velocity. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 482 0 200000 400000 600000 800000 1000000 1200000 1400000 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 u (m/s) e c ($ ) figure (6) pump energy cost as a function of stream velocity. 0 200000 400000 600000 800000 1000000 1200000 1400000 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 u (m /s) cc ($) ec ($) sum($) figure (7) total cost of double pipe heat exchanger in relation to sludge stream velocity. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 532 a comparison of (cbr) soaked test with british specifications for fine-grained soils from al-kut in iraq asst. lec. qais kadhim jahanger asst. lec. zuhair kadhim jahanger environmental engineering. dep. dep. of water resources engineering al-mustansiriyah university /iraq university of baghdad /iraq abstract: the california bearing ratio (cbr) test has been widely used in pavement design since mid 1940's. it is a relative measure of sub-grade soil or base/sub-base aggregate strength. nine samples, about 50 kg are taken from different test pits dig to 1.5m from natural ground surface, the soil is fine grained either silt or clay. the nine (cbr) specimens were compacted at optimum moisture content and at 95% of the maximum dry density of the modified compaction test were prepared. all specimens were soaked for periods of 96hr with more than 4.5kg surcharge load. penetration test was done for both two faces (top and bottom) of the specimen. the tests denoted that most cbr curves are convex upwards so no correction is needed. cbr number is less than 20 so is very poor to fair, where the best using for sub grade due to its fine grained soil. mostly cbr number that is calculated from bottom face is grater than top face, as they are less wetting than top face. the paper reveals that most cbr values are small, depended from 5mm penetration of the bottom face of specimens, which no correction method is needed for curves. key words: cbr test, fine-grained soils, proctor's compaction test, soaking مقارنة اختبار معدل التحمل (cbr) المغمور مع المواصفات البريطانية لتربة ي العراقدقيقة الحبيبات من الكوت ف زھیر كاظم جھان كیر. م.قیس كاظم جھان كیر م. م.م قسم ھندسة البیئة قسم ھندسة الموارد المائیة العراق/ جامعة بغداد العراق / المستنصریةالجامعة al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 533 الخالصة حيـث . يتم استخدامه بشكل واسع في تصميصم الطرق منذ منتصف أربعينات القرن الماضـي ) cbr(فحص معدل التحمل كغم اخذت مـن 50تسعةعينات بحدود . تربة التسوية يعتبرالفحص مقياس نسبي لقوة تربة التدرج او ركام طبقات السبيس او نمـاذج . التربة هي دقيقة الحبيبات أمـا غـرين او طـين , متر من سطح االرض1,5حفر اختبارية مختلفة بحفر يصل الى cbr) ( من الكثافة الجافة القـصوى لفحـص % 95التسعة قد تم رصها حسب محتوى الرطوبةاألمثل واعدادها عند مستوى .ص المعدل الر تم أجراء فحـص األختـراق لكـال . كغم او أكثر من االحمال الدافعة4.5ساعة مع 96ثم جميع النماذج تم غمرها بالماء لمدة أشرت االختبارات ان معظم المخططات هي محدبة الى االعلى لذلك ال تحتاج الى تصحيح ). العلوي و السفلي (وجهي النموذج لذلك التقيم هو من فقيرجداً الى مناسب، االستعمال االفضل كتربة طبقة سفلية بسبب حبيباتهـا % 20أقل من ) cbr(وان قيمة المقاسة من الوجه االسفل هي أكبر من قيم الوجه العلوي للنموذج، ألنه اقل رطوبة من ألوجـه ) cbr(وأن معظم قيم . الدقيقة .االعلى للنموذج ـ للنماذج هي ) cbr(يوضح البحث أيضاً ان معظم من الوجه السفلي للنماذج، ) ملم5( صغيرة، حيث تم اعتماده من اختراق ال .ولم تكن هناك حاجة لوسيلة التصحيح للمخططات nomenclature i. cbr: california bearing ratio ii. uscs: unified soil classification system iii. ll: liquid limit iv. pl: plastic limit v. pi: plasticity index vi. cl: clay low cohesive vii. ml: silt low cohesive introduction: in the last two decades, there has been rapidly expanding road construction programs in the middle east and in many of world's hot desert regions where evaporation exceeds precipitation, to minimize the construction cost for road projects in such regions, the use of locally available materials will always be necessary task of highways engineers (razouki, 2003). in the field of highways and roads construction, the california bearing ratio (cbr) test has been widely used in pavement design since mid 1940's. it is a relative measure of subgrade soil or base/sub-base aggregate strength (hossain, 2005). the standard shape of force-penetration curve corresponding to a cbr value is convex upward as shown in fig. (1) of typical test result. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 534 where the forces corresponding to standard curve are: 11.5 kn at 2mm penetration, 13.2 kn at 2.5mm, 17.2kn at 4mm, 20kn at 5mm, 22.2kn at 6mm and 26.3kn at 8mm. according to the curve shape, it will be no correction needed where this shape is convex upward as stated by bsi (bs 1377-9). laboratory tests of iraqi fine grained soils (clay and silt soils) for these 9 specimens in al-kut city shows the differences in curve shape so the forces strength. the objective of this study is make a comparison between cbr curves that connecting of alkut fine-grained soils of different sites from designed road, with the standard correction methods for laboratory (cbr) tests to obtain (cbr) number. it worth mentioning that the tests have been done by the authors themselves and for all specimens. methodology soil description the program consists of 9 (cbr) tests on specimens of fine grained soils (clay and silt) according to uscs and hydrometer test as shown in table (1) of al-kut city (southeast area) in soaking term as worst case, the soil is placed in the compaction mold under the specification of (astm d1883-05) and take its test series from compaction to penetration test for both faces of specimens top face and then bottom face, where tests are controlled laboratory circumferences. procedure of the test compaction cbr tests are usually carried out on test specimens at the optimum moisture content value for the soil as determined using the standard (or modified) compaction test, depended on the grain size distribution and percentage of retained on sieve no.200. next, using methods c of astm d155702 or d698 00 (for the 15.2 cm diameter mold) the specimens are made using the compaction energy as shown below in table (2)(bowels,1988)(astm, d 1557d 698): in this research the specification (astm d1557-02 c modified) is used for the soil compaction for cbr test and the equipment are explained in the following table (3): soaking the flowing standard steps as mentioning were applied to soak the specimens and prepare it for the penetration test (bowels, 1988)(astm, d1883). • after the compaction, the collar was removed then the specimen was trimmed smooth and flush with mold al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 535 • the base plate and spacer disk were removed; the mold + compacted soil had been weight and determining the wet unit weight (take sample for water content determination). • a piece of filter paper was placed on the base plate, the specimen was inverted (so the 5.1cm gap is on top), and attach the base plate so the soil is in contact with the filter paper on the base. • the perforated plate with adjustable stem was placed on the compacted soil and applied sufficient additional slotted weights to obtain the desired surcharge with in 2.2 kg but with a total surcharge weight of not less than 4.5 kg (the perforated plate is a part of surcharge weight). • the mold and weights were immersed in a container of water so the water has access to both the top and bottom of the sample and attach the dial gage (reading to 0.01 mm) in its holding brackets (tripod). • the swell gage was set to zero to start reading and recorded the time of the start of the test .take readings at 0, 1, 2, 4, 12, 24, 48, 72 and 96h of elapsed time. • at the end of 96h of soaking, the sample was removed and it was let to drain for 15 min. blot the sample surface by paper towels • the soaked sample including the mold was weight. cbr penetration penetration testing is accomplished in a manual compression machine using a strain rate of 1.27 mm/min. readings of load vs. penetration are taken at each 0.5mm of penetration to include the value of 5mm and then at each 2.5mm increment there after until the total penetration is 12.7mm(bowels,1988)(gupta,2005). results test specimens results about its swelling, cbr and curves will be explained in the following tables and figures. during soaking in cbr test, measurement of vertical movement (swelling or settlement) was carried out by means of an (0.01) mm dial gauge attached to the stem of the swelling plate (razouki,2003), as shown in fig.(2). therefore, table (4) illustrates the swelling and cbr of the specimens. loadpenetration curve the penetration loads was calculated in kilopascal (or megapascals) and the load penetration curve was drawn (astm, d1883). in some instances the load-penetration curve may be concave upward initially, because of surface irregularities or other causes, and in such cases the zero point shall be adjusted as shown in fig.(1), and the corrected curve shape should be taken to calculate the bearing ratio. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 536 bearing ratio the load values (the normal or the corrected due to the curve shape) were taken from the load – penetration curve (curves as shown from fig.3 to fig.11) for (2.5mm) and (5mm) penetrations were used to calculate the bearing ratios for each by the equation(1) (astm, d1883): cbr (%) = loadsandardthe loadcalculatedthe ×100 (1) where: the calculated load = material resistance or the unit load on the piston (pressure) for 2.5 mm or 5mm of penetration the standard load = standard unit load (pressure) for well graded crushed stone = for 2.5 mm penetration = 6900 kpa = for 5 mm penetration = 10300 kpa the bearing ratio reported for the soil is normally the one at 2.5mm penetration, when the ratio at 5mm penetration is greater, the test was rerun. if the check test gives a similar result, use the bearing ratio at 5mm penetration. where table (5) explains the calculated cbr for each specimen. calculation the following table (6) shows example for the calculation that was done for determination of loads and penetration for sample no.1: for column no. 3 and no.6 the penetration was calculated as: penetration (mm) = [( rptime .* ) ( rgdfactor ..* )] (2) where time: readings time (min.) p.r.: penetration rate = 1.27 mm/min factor: dial gauge factor=0.0025 mm/div. d.g.r.: dial gauge reading (div.) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 537 for column no.4 and no.7 the stress was calculated as: stress (kpa) = area factorrprgd ..*.. * 98.1 (3) where: d.g.r.: dial gauge reading (div.) p.r.factor: proving ring factor= 0.336 kg/div. area: plunger area= 19.4cm conclusions this paper has presented the results of an experimental work of 9 different soil samples used as subgrade soil for road site. from the results of this work, the following conclusions can be taken: 1. the soil studied was obtained from iraq, waset governorate, al-kut city(south east area). the soil is fine-grained either silt or clay (where ml or cl) belonging to the unified soil classification system and hydrometer tests. 2. cbr values are small for most specimens between 0 to14%, where depended from 5mm penetration of bottom face, so the general rating from very poor to fair, therefore; best using for sub grade usually, due to its fine grained particles. 3. mostly cbr values that were determined from bottom face of specimen are greater than top face, because that the upper layer in the mold during compaction becomes the bottom face of the specimen for cbr test. 4. the closing and faring between top and bottom curves like fig.5 and fig 6 depend on classification of soil, silt mostly has closing values for top and bottom curves, so clay has faring values between top and bottom. 5. the intersection of top and bottom curves in fig.6 resulted from low cohesive silt soil of high moisture content to dry unit wet. 6. the linear behaviour of curves like in fig.11 explains the constant increasing for strength of soil to penetration due to particle size of high percentage of silt. acknowledgment special thanks to andrea engineering test laboratory to allow us to use their devices and information. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 538 references 1. astm d1883-05,"standard test method for cbr (california bearing ratio) of laboratory-compacted soils", 2005. 2. astm, d 698-00, "standard test for laboratory compaction characteristics of soil using standard effort", november 2003. 3. astm, d 1557-02, "standard test for laboratory compaction characteristics of soil using modified effort", november 2003. 4. bowels, j.e.," engineering properties of soils and their measurement", 2nd edition, mcgraw-hill, 1988. 5. british standard institute, "bs 1377-9:1990" licensed copy: robert mcapline, amec capital projects ltd, november 2004. 6. gupta, r.d. et al," effect on cbr value and other geotechnical properties of fly ash mixed with lime and nom-woven geofibers, "college of eng. &tech., university of polytechnic, amu, aligahra (india), october 2005. 7. hossain, s., dickerson, g.m. and weaver c.b.," comparative study of vtm and aashto test method for cbr", co materials division, vdot, september 2005. 8. razouki, s.s. and al-azawi, m.s.," long-term soaking effect on strength and deformation characterises of a gypsiferous sub grade soils", engineering journal of the university of qatar, vol.16, pp46-60, 2003. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 539 table (1) geotechnical properties for al-kut specimens sieve analysis & hydrometer index properties sample no. sand% silt% clay% ll% pl% pi% natural water content% uscs 1 6.6 46.5 46.9 44 23 21 10 cl 2 4.5 33.2 62.3 43 23 20 14.3 cl 3 7.3 62.6 30.1 41 26 15 13.1 ml 4 5.9 64.4 29.7 34 23 11 12.8 ml 5 8.1 53.5 38.4 36 21 15 14.1 cl 6 6.8 63.3 29.9 36 25 11 14.6 ml 7 5.3 71.5 23.2 35 24 11 13.8 ml 8 6.4 51.9 41.7 41 20 21 18.8 cl 9 7.2 67.7 25.1 32 23 9 28.9 ml table (2) cbr compaction specification method mould (mm) passing sieve no. layers blows rammer weight (n) a 101.6 4 3 25 24.5 b 101.6 9.5mm 3 25 24.5 d 698: c 152.4 19mm 3 56 24.5 a* 101.6 4 5 25 44.5 b 101.6 9.5mm 5 25 44.5 d 1557: c 152.4 19mm 5 56 44.5 * d1557 a is used to determine the water content and dry unit weight al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 540 table (3) compaction apparatus (1)(4)(7) equipments and accessories cbr test standard remarks loading machine capacity of 44.5kn uniform movement rate of 1.27mm/min. mold size diameter= 15.2 cm height= 17.8 cm or equivalent extension collar diameter= 15.2 cm height= 5 cm spacer disc diameter= 15.1 cm height= 6.14 cm or 5.1 height as available compaction rammer 44.5 n weight or 24.5 n as standard swell base plate diameter= 15 cm height= 0.625 cm perforated with 42 hole hole diameter= 0.16 cm surcharge weight diameter= 15 cm weight= 2.268 kg not less than 4.5 kg al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 541 table (4) specimen swelling and cbr number cbr 2.5mm cbr 5mm sample no. swelling % top bottom top bottom general rating 1 7.5 1.3 3.69 1.74 8.55 * fair 2 5.25 2.4 * 6.5 1.95 7.35 very poor 3 3.32 4.42 7.24 5.9 8.57 * fair 4 1.66 2.6 2.75 3.15 2.92 * very poor 5 1.34 2.25 4.5 2.55 5.35 * very poor 6 4.27 4.05 13.9 * 6.33 10.95 fair 7 4.17 3.77 7.1 5 9.24 * fair 8 2.85 3 3.25 * 3.15 2.7 very poor 9 1.65 2.3 3.45 3.3 4.15 * very poor * represent the cbr value of specimen table (5) cbr values compaction test sample no. uscs max. dry density kn/m3 optimum moisture content % cbr value at 95% compaction 1 cl 18.27 10.1 8.55 2 cl 18.04 10.6 2.4 3 ml 17.85 13.2 8.57 4 ml 17.95 14.3 2.92 5 cl 17.88 12.5 5.35 6 ml 18.02 11.5 13.9 7 ml 17.91 12 9.24 8 cl 18.28 12.7 3.25 9 ml 17.95 14.9 4.15 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 542 table (6) sample no.1 calculations 1 2 3 4 5 6 7 top face bottom face time (min.) dial gauge reading (div.) penetration (mm) stress (kpa) dial gauge reading (div.) penetration (mm) stress (kpa) 0 0 0 0 0 0 0 0.5 12 0.605 20.3 41 0.53 70 1 27 1.2 45 72 1.09 122 1.5 41 1.8 70 107 1.64 181 2 55 2.4 93 145 2.18 246 3 77 3.61 130 228 3.24 387 4 97 4.84 164 308 4.31 522 6 135 7.28 230 434 6.54 737 8 173 9.73 294 517 8.87 877 10 218 10.15 370 577 11.26 279 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 543 fig.1 typical cbr test results curves (bs 1377-9) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 544 b. specimen before penetration a. specimen in swelling tank c. cbr penetration experimental set-up d. top face penetration e. bottom face penetration fig.2 cbr penetration apparatus al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 545 fig. 4 cbr curve for test sample no.2 stress penetration curve 0 2 4 6 8 10 12 0 1 2 3 4 5 6 7 8 9 10 x 10 0 penetration (mm) s tr es s (k pa ) bottom top fig.5 cbr curve for test sample no.3 stress penetration curve 0 2 4 6 8 10 12 0 1 2 3 4 5 6 7 8 9 10 x 10 0 pene tration (m m ) st re ss (k pa ) bottom top al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 546 fig.6 cbr curve for test sample no.4 stress penetration curve 0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8 9 10 x 10 0 penetration (mm) s tr es s (k p a) top bottom fig.7 cbr curve for test sample no.5 stress penetration curve 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 x 10 0 penetration (mm) s tr es s (k p a) bottom top fig.8 cbr curve for test sample no.6 stress penetration curve 0 2 4 6 8 10 12 0 1 2 3 4 5 6 7 8 9 10 x 10 0 penetration (mm) s tr es s (k pa ) bottom top al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 547 fig.9 cbr curve for test sample no.7 stress penetration curve 0 2 4 6 8 10 12 14 16 0 1 2 3 4 5 6 7 8 9 10 x 10 0 penetration (mm) s tr es s (k pa ) bottom top fig.10 cbr curve for test sample no.8 stress penetration curve 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 10 x 10 0 pe netration (mm) s tr es s (k p a) top bottom fig.11 cbr curve for test sample no.9 stress penetration curve 0 2 4 6 8 10 0 1 2 3 4 5 6 7 8 9 10 x 10 0 penetration (mm) s tr es s (k pa ) bottom top 3-4-2010.pdf 11-4-2010.pdf al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 253 performance analysis of cdma power control algorthims hayder miri hamzah electronic and communication engineering haydermiri@yahoo.com abstract it is well known that power control plays a very important role in cdma cellular system when mobile subscriber moves in the cell, especially when very close to the border; the realization of power control is practically based on the result of the detection of signal power. so different techniques are analyzed in details such as distributed balancing, distance based and constrained power control. also stepwise optimal removal algorithm (sora) is introduced and evaluated to enhance carrier to interference ratio (cir) and capacity compared with previous techniques where the outage probability remains relatively low at higher users. cdma تحليل اداء خوارزميات سيطرة القدرة ألنظمة حيدر ميري حمزةم.م. هندسة الكترونية واتصاالت الموجز يلعب دور مهم جدا في األنظمة الخلوية بأستخدام تكنولوجيا (power control)من المعروف ان (cdma)أثناء حركة المحطة المتنقلة ((mobile قريبة جدا من في داخل الخلية، خصوصا عندما تكون تم في هذا البحث دراسة وتحليل ( عمليا على تحسس قوة األشارة.power) controlحدود الخلية؛ يعتمد constrained power)و ) distance based)و ) distributed) (balancingمختلفة مثل تقنيات control . خوارزمية ) وتقييمباألضافة الى تقديم(stepwise optimal removal algorithm sora حيث يبقى بالتقنيات السابقةمقارنة لتقليل التشويش وزيادة السعة(outage probability) .منخفض نسبيا مع زيادة عدد المستخدمين abbreviations gmb: link gain between mobile m and its home base station b pj: total power : total power received at mobile m ber: bit error rate cdma: code division multiple access cir: carrier to interference ratio eb/no: energy per bit over the total noise spectral density fdma: frequency division multiple access hayder miri hamzah al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 254 ib: index of the mobiles assigned to base station b. is-95: interim standard 95 nm: noise power of mobile m pbm: power allocated to mobile m from base station b pmax: maximum power per mobile. pt: total power transmitted by each base station r: bit rate r: distance from base station b sir: signal to interference ratio sora: stepwise optimal removal algorithm tdma: time division multiple access w: channel band width z: normalized downlink gain matrix λ: path loss exponent of the system introduction cdma technology has many features such as higher user capacity compared to traditional technologies such as fdma and tdma, universal frequency reuse, multipath rejection, interference rejection, and communication security (m. zorzi, 1994). power control is one of the most important issues in a cdma system because it has a significant impact on both performance and capacity it is the most effective way to avoid the near-far problem and to increase capacity (w.tam and f. lau., 1997). power control refers to the strategies or techniques required in order to adjust, correct and manage the power from the base station and the mobile station in an efficient manner. in the is-95 system (tia/eia interim standard-95, 1993), downlink power control was far less sophisticated than uplink power control, resulting in the downlink capacity being more constrained than uplink (lei song and jack holtzman, 1998), and (tatcha chulajata and hyuck kwon, 2000). downlink power control serves the following important functions (andrew viterbi, 1995), and (kaveh pahlavan and allen levesque, 1995) 1. equalizes the system performance over the service area (good quality signal coverage of worst-case areas). 2. minimizes the necessary transmission power level to achieve good quality of service. this reduces the co-channel interference in other cells, which increases the system capacity. capacity of a cdma system the main parameters that affect the capacity of cdma system are: 1. carrier to interference ratio (cir) / signal to interference ratio (sir): the cir and sir terms are often used interchangeably even though there is a slight difference between the two, if power control is not implemented many problems such as the near-far effect will start to dominate and consequently will lower the capacity of the cdma system. however, when the power control in cdma systems is applied, it allows users to share resources of the system equally between themselves, leading to increased capacity. gain in cir can be utilized for increasing the number of users per cell in cdma, and thus, improvements in system capacity can be achieved. the definition of the cir will be defined as the ratio of the unmodulated desired signal power over the unmodulated interference power. this can be written mathematically as (nuaymi, godlewski, 2001), and (abdurazak mudesir, 2004): performance analysis of cdma power control algorthims 255 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 cirm (1) which describes the cir of mobile m as a ratio, where the numerator is the link gain between mobile m and its home base station b (gmb), multiplied by the power allocated to mobile m (pbm). the denominator is the sum of all the link gains from mobile m to the b base stations in the system multiplied by their total transmitted power ( , subtracted by the desired carrier power which corresponds to the numerator , and adding the receiver noise power of mobile m (nm). however the receiver noise power is usually neglected. link gain is the magnitude change of a signal travelling along a link expressed as a factor. in cdma, because the information is spread across a large bandwidth, it is able to have a large processing gain so that it can operate with a cir less than 1, meaning that the interference power is larger than the carrier power. practically, cdma system requires typically a cir of around -17db to operate. 2. eb/no: the energy per bit over the total noise spectral density eb/no, is often used as the real quality indicator for adequate performance and is sometimes called the despread sir. it is related to the cir (nuaymi, godlewski, 2001): cir= (2) where r is bit rate, and w is channel band width. 3. outage probability: it is usually referred as the probability that the cir of a mobile falls below a required threshold, outage probability is often used to evaluate the performance and capacity of a cdma system. in some papers, it is defined as the ratio of the number of disconnected or handed over users to that of the total users in the system (nuaymi, godlewski, 2001). therefore, a mobile is considered in outage in simulation if its cir is below the minimum required cir (-17db) or if the mobile is disconnected from the system. 4. ber as the name implies, a bit error rate is defined as the rate at which errors occur in a transmission system. this can be directly translated into the number of errors that occur in a string of a stated number of bits. if the medium between the transmitter and receiver is good and the signal to noise ratio is high, then the bit error rate will be very small possibly insignificant and having no noticeable effect on the overall system. however if noise can be detected, then there is chance that the bit error rate will need to be considered. ber is often used as the quality measurement of a system because in practical system, cir will be time-variant therefore the average cir will not be related to the average ber (d. novakovic and m. dukic, 2000), and (l. william, 1991). power control algorithm with appropriate power control, the cdma offers high capacity in comparison to fdma and tdma. since cdma systems do not explicitly schedule time or frequency slots among users, the central mechanism for resource allocation and interference management is power hayder miri hamzah al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 256 control. each use changes its access to the resources by adapting its transmitting power to the changing channel and interference conditions. therefore power control is a significant design problem in cdma systems. power control encompasses the techniques and algorithms used to manage the transmitted power of base stations and mobiles. power control helps to reduce co-channel interference, increasing the cell capacity by decreasing interference and prolonging the battery life by using a minimum transmitter power. in cdma systems power control insures distribution of resources among users. when power control is not implemented, all mobiles transmit their signal with the same power without taking into consideration the fading and the distance from the base station, in this case mobiles close to the base station will cause a high level of interference to the mobiles that are far away from the base station (abdurazak mudesir, 2004). generally there are two possible groups of power control schemes, distance driven and cir driven. distance driven schemes are open-loop schemes that try to estimate the distance between the base station and the mobile based on the received signal strength at the mobile. from this estimate, which it receives from the mobile, the base station will increase signal power or decrease signal power depending if the mobile is close or far away. these types of schemes are best suited for non-shadowed environments as signal strength will be a more accurate estimate of distance. the cir driven schemes uses a closed loop mechanism to balance the cir of each mobile so that the cell or system has the maximum common cir possible. in these schemes, each mobile will send its cir to the base station, and the base station will then decide whether to increase or decrease signal power to the mobile based on the cir ratio (r. prasad, 1996). distributed balancing power control the aim of this algorithm is to determine the transmitted power to each mobile to ensure that the received cir is the same for all mobiles within the cell. this is achieved by balancing the link quality for all the users within each cell, i,e. calculates the optimal transmit power assignment for each mobile within the cell, taking into consideration all the neighboring cells. this algorithm is distributed in the sense that each cell operates independently of other cells only the received powers and an estimate of the link gain between the mobile and base station is needed. to achieve this, feedback is needed to report the received power at each mobile, and the base station needs to estimate the link gain between the base station and mobile (andrew viterbi, 1995), (kaveh pahlavan and allen levesque, 1995), and (d. kim, 1999) = max, min (3) the above link quality balancing problem is solved by maximizing the minimum cir for all users in the cell. if we assume nm is negligible, this can be solved by the following steps: bm (4) b = (5) where ib is the index of the mobiles assigned to base station b. performance analysis of cdma power control algorthims 257 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 essentially represents the total power received at mobile m, normalized to the link gain to its home base station b. this value can then be used to calculate the weighting or fraction of the total base station power mobile m should receive. the power allocated to mobile m by its home base station b, therefore it's calculated by: pbm (6) the result of this power control algorithm is that all mobiles of base station b will have a common cir: = (7) distance based power control it is an open loop power control algorithm as there is no feedback involved. assuming that the base station can estimate the distance of a mobile based on the received signal strength, then it allocates power to users based solely on their distance from their home base station. therefore it tries to improve the system’s performance by giving mobiles far away from the base station more power to increase their cir, and reducing the power to the close in mobiles which already experience a high level of cir. the power allocation to any mobile m throughout the cell serviced by base station b is based on the following formula (andrew viterbi, 1995), (l. william, 1991), and (r. gejji, 1992): pbm = fm pmax (8) where fm is a fraction represented by: fm = (9) where n is the power control factor, r is the distance from base station b to the corresponding mobile m which has been assigned to it, r is the radius of the cell, and dmin is a value that represents the distance at which the power allocation stays constant. the purpose of dmin is that if a mobile is very close to the base station, according to the power allocation formula, it will receive very little power that it might now have a lower cir than the far users. therefore, a value called dmin is set so that there is a minimum on how much power can decrease by. l. william (l. william, 1991) concluded that the best choice for n is 2, with a corresponding dmin of 0.55r. the choice of n=2 however is best for a system where no fading has been considered as in l. william's case. if a system is analyzed with fading, then the choice of n=4 would be more appropriate. if cell 1 is the home cell, then x1= r. therefore the power received from the home base station and the power received from the other base stations are: phome=pt (10) pother= (11) hayder miri hamzah al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 258 where pt is the total power transmitted by each base station and is assumed to the same for all the base stations, and λ is the path loss exponent of the system. the total interference factor is defined as xi= (12) the total power received is: prec = phome+pother (13) prec = pt . . xi (14) pbm = fm pmax (15) where: fm = (16) pbm is the power allocated to mobile m in base station b, and pmax is the maximum power per mobile. if the hexagonal cells can be approximated by circular cells with radius r, then the density will be: (17) then the total transmitted power is pt: (18) (19) (20) pt = n. pmax . f (dmin) (21) cir (22) constrained power control: this algorithm is based on the same concept as the distributed balancing algorithm except there is a constraint on the maximum base station transmitter power, with the aim to performance analysis of cdma power control algorthims 259 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 minimize this power. this algorithm can be operated distributedly with no centralized control of the cells. each cell in the system balances the link gains in its cell so that all the mobiles have the largest common cir. following this, the base station of each cell adjusts its total transmitting power by reducing its total power by a calculated factor, if the common cir of a particular cell is above the minimum required cir. if the common cir is below the minimum required cir, no adjustment is made. the power adjustment factor is equal to circommon/cirrequired. the result of this base station power adjustment process is that it will try and balance the common cir of each cell throughout the system (q. wu, 1999), and (d. kim, 1999). = max, min (23) bm (24) b = (25) where ib is the index of the mobiles assigned to base station b. the power allocated by base station b to mobile m is: (26) the result of this power control algorithm is that all mobiles of base station b will have a common cir of: (27) stepwise optimal removal algorithm (sora): it is possible that if there are too many mobiles per cell, the common cir of some cells or all cells is below the required cir. therefore, some mobiles will need to be disconnected from the system to improve the cir of the other mobiles. a simple strategy that is introduced is that after l iterations, if the common cir of a cell is below the required cir, then the mobile that requires the most power from the base station is disconnected. this continues until the cir of all mobiles in that cell is at or above the required cir, where all the link gains of every mobile to every base station of a cellular system are known to a central computer, and from which the power allocation to every mobile is calculated has been explored by a number of people. in order to balance the huge number of link gains in a cellular system, an eigenvalue problem needs to be formulated. the problem is that in cdma systems, because all users in a cell share the same frequency bandwidth, this will result in three dimensional link gain matrices. cdma downlink power control problem was successfully formulated into an eigenvalue problem by assuming that the cir within a cell is balanced, therefore he was able to simplify the link gain matrix into two dimensional (q. wu, 1999). hayder miri hamzah al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 260 it is possible that after solving the link quality balancing problem of the system (and hence balance the cir of the system) that the value of the cir for all the mobiles might be inadequate, therefore there needs to be some sort of strategy to disconnect mobiles to improve the overall quality of the system. this includes the stepwise optimal removal algorithm (sora) which gives a good approximation to the upper performance bounds of a power control algorithm, this is as following: 1. determine cir * corresponding to the z matrix. if cir * ≥ cir required, then use corresponding eigenvector p * and stop, else set m'=m. 2. remove mobile k, where the cir * of the remaining system is the largest. this forms a new matrix z' with a size of (m'-1) x (m'-1). determine cir * corresponding to z' and if cir * ≥ cir required, then use corresponding eigenvector p * and stop, else set m'=m-1 and repeat step2. system model: this cdma cellular system consists of n cells with m active mobiles. the total interference experienced by a mobile consists of the sum of the powers of the other m-1 active mobiles. each of the m mobiles in cell k is mapped to i, where 1> i > m. using these notations, we can write the cir of mobile i as: ciri (28) where k and i are the cells which mobile i and j belong to gik is the link gain between mobile i and its home base station in cell k. pi is the power allocated to mobile i in cell k. pi is the power allocated to mobile j in cell l. gil is the link gain between i and the interfering base station in cell l. by normalizing the link gain: ciri (29) where, (30) the normalized downlink gain matrix z = {zij} (cir) maximum is denoted by cir * is equal to: cir * (31) where λ * is the largest real eigenvalue of the z matrix, and p * , the vector of the power allocations to achieve cir * , is the corresponding eigenvector. simulation results: distributed balancing power control: figure 1 shows the results for the system-level analysis of the distributed balancing power control. the distributed balancing power control is able to achieve a maximum capacity of 26 users/cell at 0% outage probability. performance analysis of cdma power control algorthims 261 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 distance based power control: figure 2 shows the results for the system-level analysis of the distance based power control. the distance based power control is able to achieve a maximum capacity of 26 users/cell at 0% outage probability constrained power control: figure 3 shows the results for the system-level analysis of the constrained power control. the constrained power control is able to achieve a maximum capacity of 35 users/cell at 0% outage probability. a simple disconnection strategy was used which was the mobile that requires the most power (and hence would improve the cell’s common cir the most) would be disconnected. essentially, the only outage that occurs in this algorithm is the number of users disconnected as the algorithm continues to disconnect users until the system’s cir is greater or equal to the minimum required cir. therefore the outage probability in this algorithm is the number of disconnections over the total number of users in the system. stepwise optimal removal algorithm (sora): figure 4 shows the results for the system-level analysis of stepwise optimal removal algorithm power control. it is able to achieve a maximum capacity of 37 users/cell at 0% outage probability. figure 5 shows the results of all the power control algorithms. conclusion: the stepwise optimal removal algorithm power control and constrained power control are clearly have a better performance at 0% outage probability, with the stepwise optimal removal algorithm power control edging out the constrained power control by two users/cell. their outage probabilities also remain relatively low at higher users per cell as it increases steadily unlike the distance based and distributed balancing which increases rapidly soon after exceeding 0% outage. the distance based power control clearly appears to be very similar to the distributed balancing power control in terms of performance with a very similar outage curve. references: [1] abdurazak mudesir, "power control algorithm in cdma systems", international university bremen, submitted as a guided research 2004. [2] andrew viterbi "cdma principles of spread spectrum communication". addisonwesley, reading 1995. [3] c. chang and f. ren. "down-link power control in ds/cdma cellular mobile radio network", in third annual international conference on universal personal communications. 1994. [4] d. kim, "a simple algorithm for adjusting cell-site transmitter power in cdma cellular systems," ieee transactions on vehicular technology, 1999. [5] d. novakovic and m. dukic, "evolution of the power control techniques for ds-cdma toward 3g wireless communication systems," ieee communications surveys & tutorials, 2000. hayder miri hamzah al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 262 [6] kaveh pahlavan and allen levesque, "wireless information networks". john wiley, new york, 1995. [7] lei song and jack holtzman, "cdma dynamic downlink power control. in proceedings of the vehicular technology conference volume 2, ottawa, canada, 1998. [8] l. william, "overview of cellular cdma," ieee transactions on vehicular technology, 1991. [9] m. zorzi, "simplified forward-link power control law in cellular cdma," ieee transactions on vehicular technology, vol. 43, 1994. [10] nuaymi, godlewski, and lagrange. "power allocation and control for the downlink in cellular cdma networks", ieee international symposium on personal, 2001. [11] q. wu, "performance of optimum transmitter power control in cdma cellular mobile systems," ieee transactions on vehicular technology, 1999. [12] r. gejji, "forward-link-power control in cdma cellular systems," ieee transactions on vehicular technology, 1992. [13] r. prasad, "cdma for wireless personal communications", artech house, boston, 1996. [14] tatcha chulajata and hyuck kwon, "combinations of power controls for cdma 2000 wireless communications system". vehicular technology conference, boston, 2000. [15] tia/eia interim standard-95. mobile base station compatibility standard for dualmode wideband spread spectrum cellular system. technical report, telecommunications industry association, 1993. [16] w. tam and c. lau, "analysis of power control and its imperfections in cdma cellular systems," ieee transactions on vehicular technology, 1999. [17] w.tam and f. lau. "capacity analysis of a cdma cellular system with power control schemes". 6 th ieee international conference on universal personal communications, 1997. figure 1 distributed balancing power control. performance analysis of cdma power control algorthims 263 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 figure 2 distance based power control. figure 3 constrained power control. hayder miri hamzah al-qadisiya journal for engineering sciences, vol. 5, no. 3, 253-264, year 2012 264 figure 4 stepwise optimal removal algorithm. figure 5 distributed, distance, constrained, and sora pc. al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 424 laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures ahmed i. ahmed assist. lect. / hwy and transportation department university of al-mustansiriyah ahmedjb_ahmed@yahoo.com abstract the mechanical properties of asphalt mixtures used in highways construction depend to large extent on the type and quantity of the used asphalt. with time any asphalt pavement can exhibit various distresses that will eventually lead to the pavement failure. various types of additives and modifiers have been used in asphalt to mitigate the distresses. fiber is one of the additives used for this purpose. the principal function of the fiber is to provide additional tensile strength in the resulting composite. this could increase the amount of strain absorbed during the fatigue and fracture process of the mixture. in local asphalt pavement, the severity of permanent deformation and thermal cracking has been increased due to the increase in track axle loads, tire pressure, and the difference in pavement temperature, therefore, the modified dense graded mixtures with polypropylene fibers suggested for use in highway wearing courses to provide adequate resistance to permanent deformation and to provide additional tensile strength in the resulting composite. the effects of variation in polypropylene fiber content, asphalt cement content, aggregate gradation and testing temperature are evaluated through the results of marshall methodology, indirect tensile strength, indirect creep test, and ultrasonic testing. the results obtained from this study showed that the ppf improved the mixture’s performance in several unique ways against the anticipated major pavement distresses. the addition of (0.3%) polypropylene fiber by weight of total mix with type (a) aggregate grading will help in produce more flexible mixtures that are also more resistant to permanent deformation and thermal cracking. the relationship between the dependent and independent variables was examined by descriptive statistical analysis. the spss statistical package was used to perform this analysis. ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 425 keywords: polypropylene fiber, dense graded, additives, indirect tensile, temperature. introduction asphalt cement modifiers have been used in pavement technology to enhance pavement performance and reduce different types of pavement distress, of which, rutting, low temperature cracking, load associated fatigue cracking, stripping, and hardening are the most common. fiber is one of the additives used for this purpose (thomas and haiming, 1999). using fibers to improve the behavior of materials is not a new concept. fibers are widely used as reinforcing agent in concrete, however, the modern ways of fiber reinforcement started in the early 1950s (saeed and ali, 2000). the principal function of the fiber is to provide additional tensile strength in the resulting composite. this could increase the amount of strain absorbed during the fatigue and fracture process of the mixture fibers are sometimes added to stabilize the binder during mixing and placement. an additional benefit of using fibers is that fibers have been shown to allow increased asphalt binder contents and thus increase film thicknesses thereby increasing durability (thomas and haiming, 1999). the results obtained from field studies show that the addition of fiber will help in produce more flexible mixtures that are also more resistant to cracking (saeed and ali, 2000). the addition of fibers to asphalt concrete improved the fixation of the asphalt binder in the mix. this relates to less bleeding and improved skid resistance over unmodified mixtures of the same design. fiber modification also allowed for an increase in film thickness, resulting in less aging and improved binder characteristics. the addition of fibers also resulted in the reduction of temperature susceptibility of asphalt mixtures (serfass and samanos, 1996). a multitude of fibers and fiber materials are being introduced regularly in the market as new applications such as polyester fiber, asbestos fiber, glass fiber, polypropylene fiber (as shown in figure 1), carbon fiber, cellulose fiber, etc. (saeed and ali, 2000). objective of the study the objective of this study is to evaluate the effect of polypropylene fiber at different contents (0.1, 0.2, and 0.3) percent by weight of total mix within the dense graded mixtures (types a&b) on the mechanical and volumetric properties, vertical strain, indirect tensile strength and the modules of laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 426 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 elasticity of these mixtures and compare the performance characteristics of the fiber modified mixtures with that of control mix without fiber. materials the materials used in this study are locally available and currently used in road construction in iraq except polypropylene fibers which are available in local market in baghdad. asphalt cement one grade of asphalt cement was used in this work including a.c (40-50) from daurah refinery at different contents (4.0, 4.5, 5.0, 5.5, and 6.0) percent by weight of total mix. aggregate one type of crushed aggregate was brought from the hot mix plants of taj al-qethara contracting company. the source of aggregate is from al-nibaay quarry. two gradations with a top size of (19 mm, 12.5mm) respectively were used according to state corporation of roads and bridges (scrb, 2003). the specification limits and selected gradation of hma mixtures are presented in figures 3 and 4 respectively. mineral filler protland cement was used as mineral filler which is obtained from tasluga cement factory. polypropylene fiber high performance short 19mm polypropylene fiber (ppf) was used in this study as shown in figure 2; it was brought from fosrok company. the physical properties of ppf are presented in table 1 (murat, 1983). test methods the following tests were performed on the prepared laboratory samples to evaluate the performance of dense graded mixtures: 1. resistance to plastic flow (marshal method, astm d 1559). 2. standard test method for percent of air voids in compacted dense graded mixtures, astm d 2041. 3. indirect tensile strength, astm d 4123, 4. creep test , and 5. ultrasonic testing bs 1881 part 203. presentation of test results 1. resistance to plastic flow (marshall test) marshall methodology for mix design is used in this work as an indicator of resistance to plastic flow. stability, and flow were tested for each specimen using astm d 1559 and the results are presented in figures 5 and 6 for mix type a and b respectively. 2. calculation of the percentage of voids in total mix (vtm) in each compacted specimen: the bulk density and maximum theoretical specific gravity tests were conducted according to astm d 2726 and astm d 2041 respectively and the voids in total mix (vtm), voids filled with asphalt (vfa), and voids in mineral aggregate (vma) of the different paving mixtures are calculated and presented with other marshall test results in figures 5 and 6 respectively. 3. effect of asphalt cement and polypropylene fiber contents on marshall properties in order to evaluate the variation of properties of dense graded mixtures with type a and b aggregate grading at different asphalt and ppf contents, five asphalt content (4.0, 4.5, 5.0, 5.5, 6.0) % by weight of total mix were selected according to scrb with three contents of ppf, (0.1, 0.2, ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 427 0.3) % by weight of total mix and compare the properties of these mixtures. the effect of these variables is shown in figure 5 and 6 respectively as stated previously. from the inspection of the results, the modified mixture with (0.3%) ppf and with type (a) aggregate grading improve the resistance to plastic flow with acceptable stability and volumetric properties values according to state corporation of roads and bridges (scrb, 2003) when compared with that of control mix without fiber. the use of ppf at (0.1 and 0.2) percent with type (a) may be lead to bleeding of asphalt from surface because the resulting mix has an air voids less than the recommended value of (3-5) % at 5% asphalt content and more. the use of (0.1%) ppf with type (b) aggregate grading gives the highest values of stability, resistance to plastic flow, and density when compared with control mix without fiber and mixes containing other polypropylene contents. also from the inspection of the results it’s found that the addition of (0.1%) ppf to type b mixtures reduce the percent of air voids (vtm) in comparison with that in the control mix but the most values still outside the recommended values. poor performance still as in the control mix when (0.2% and 0.3%) ppf were used. an increase in fiber content in the mixture followed an increase in the vtm this was probably due to greater surface areas to be coated. fiber and fine aggregate (composes 70% of the mix) absorb binder and then leads to increase the voids in the mixture. in addition, fine mixtures with higher fiber contents might experience lower compact ability, leading to higher air void values. 4. indirect tensile strength test results in this study the indirect tensile strength test was conducted to evaluate the tensile properties of different asphalt concrete mixtures that prepared at optimum asphalt content for each ppf content and for both type a and b grading. the test was performed at different temperatures include (5cº, 15cº, 25cº, and 40cº) and the results for both type of mix (a and b) are shown in figures 7 and 8 respectively. the indirect tensile strength (st) was then calculated as follows in accordance with astm d 4123: where: pult. = ultimate applied load, t = thickness of the specimen, and d= diameter of the specimen. the addition of ppf resulted in the reduction of temperature susceptibility of asphalt mixtures. mixtures containing polypropylene fibers were found to have higher tensile strengths and resistance to cracking. adding ppf enables developing mixtures rich in bitumen and therefore displaying high resistance to cracking. mixtures containing polypropylene fibers of (0.3%) with type (a) aggregate grading were found to have higher tensile strengths and resistance to cracking over unmodified mixtures of the same design. fiber modification at 0.3% allowed for an increase in film thickness, resulting in improved binder characteristics and the fixation of the asphalt binder in the mix. also the same results obtained when (0.2%) ppf with type (b) aggregate grading was used. 5. creep test results creep is an important measure of modified asphalt performance, its ability to elastically recover deformation. since asphalt pavement are designed to be flexible, they must quickly return to their original configuration after loading (muncy, and prudhomme, 1987). the diametric – indirect tensile creep test has been used to determine the vertical strain of asphalt mixtures by measuring strain – time values. this test is performed on marshall specimens at laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 428 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 corresponding optimum asphalt content (oac) for each polypropylene content under a constant stress of (0.1mpa). the specimen is loaded to static stress of 0.1 mpa for 1 hour, and the deformation is recorded at certain time increments of (0.1 , 0.25 , 0.5 , 1 ,2 ,4 ,8 ,15 ,30 ,45 ,and 60 min). the load is then released, and the recovered strain for 1 hour is recorded, at the same periods. the vertical strain is calculated by using the following formula: =∆h/do (mm/mm) where: ∆h= the total measured vertical deformation at a certain loading time (mm), and do=the original diameter of specimen (mm). from the results of this test for aggregate grading type (a) showing in figure 9, 10 and 11, the vertical strain tends to declined when the polypropylene fiber is added at 20c° and 40c°, but the samples without and with 0.1% and 0.2% ppf cannot resist the hottest temperature at 60c°. at this temperature the resistance to the deformation occurred at 0.3% ppf only while other samples tend to failed. for type b aggregate grading, at 20c° and 40c° the best resistance to the deformation under the combined action of load and temperature occurs at 0.1% ppf as shown in figures 12 and 13. figure 14 shows that at the hottest temperature (60c°) all samples with and without ppf tend to failed because this type of mix contains about 70% fine particles that make these mixes unable to carry the applied load at this high test temperature. 6. ultrasonic testing the main advantage of this test is that it is nondestructive. in addition, the test can be performed on both laboratory-prepared specimens and field cores (rajas, and yaun, 1999). the prepared specimens can be used to perform ultrasonic tests at 25c°. the elastic modulus of a specimen is measured using an ultrasonic device containing a pulse generator and a timing circuit, coupled with piezoelectric transmitting and receiving transducers. the timing circuit digitally displays the time needed for a wave to travel through a specimen. the receiving transducer, which senses the propagating waves, is connected to an internal clock. the clock automatically displays the travel time, (t) that can be used with the density of the specimen to calculate the constrained modulus, md, as: md = ρvp² = ρ (l/t)² where: ρ: density, vρ: compression wave velocity, and l: average length of the specimen. t: travel time. then the elastic modulus of the hma specimens, ed, can be determined from: the poisson´s ratio, , can be assumed based on experience. the test results in figure 15 shows that mixture containing (0.3%) polypropylene fibers with type (a) aggregate grading were found to have the higher elastic modulus over the control and other modified mixtures. ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 429 statistical models for creep test the effect of temperature, time, polypropylene content, and elastic modulus on vertical strain of dense graded mixtures is examined by descriptive statistical analysis. the relationship between the dependent and independent variables was examined using the spss statistical package. the package was used to perform the required statistical analysis. the results of the statistical analysis are presented in table 2. the (r 2 ) obtained values are substantially high except for type b mix (unloading case) because the tested samples failed during the loading stage at 60c° as shown in figure 14 previously. this would suggest that the selected form of models is reasonably capable of producing results with adequate accuracy within the examined range of material properties and contents. from the inspection of these models, the vertical strain reduced with the increase of ppf when type a mix is used. while for type b the reverse is occurred. this enhances the results of work plan that stated the optimum ppf occurred at 0.3% and 0.1% for types a and b respectively. where: mix: vertical strain of dense graded mixtures, t: testing temperature (c°), ppf: polypropylene fiber content (%), t: time in minutes, ed: elastic modulus of dense graded mixtures (mpa), and see: standard estimation error. conclusions on the basis of the materials used and laboratory testing performed in this study, the following conclusions can be made: 1. in order to satisfy the requirements of desirable mixture properties for dense graded mixtures with types (a) and (b) aggregate grading, a relatively high optimum asphalt content (5.2%) and (5.1%) by weight of total mix respectively is required with optimum polypropylene contents (0.3%) and (0.1%) by the weight of total mix for types (a) and (b) respectively while (4.8%) and (4.7%) are required for the conventional dense graded mixtures without fiber types (a) and (b) respectively. 2. the use of polypropylene fiber as a modifier additive with types (a) and (b) aggregate grading has improved marshall stability by (9%, and 7%), increased the resistance to plastic flow by (13%, and 12%) and decreased the air voids by (42%, and 26%) respectively in comparison with the conventional dense graded mixtures without fiber. 3. mixtures containing (0.3%) and (0.2%) polypropylene fibers by weight of total mix with types (a) and (b) aggregate grading were found to have higher tensile strengths and less susceptible to low temperature effects over the control mix and as follow: an increase of (51%, 15%, 20%, and 10%) and (38%, 15%, 17%, and 10%) in indirect tensile strength (st) at (5c°, 15c°, 25c° and 40c°) respectively. 4. the results of creep test showed that the ppf improved the mixture’s performance against the anticipated permanent deformation. type a mix with 0.3% ppf and type b mix with 0.1% ppf reduced the permanent deformation by (15%, and 33%) at 20c°and (38%, and 46%) at 40c° over the control mix respectively. while at 60c°, only the 0.3% ppf with type (a) resisted the action of the hottest temperature and all other mixtures failed early. 5. the ppf content reflected a remarkable effect on elastic modulus of dense graded mixtures. it’s found that the use of 0.3% and 0.2% ppf with type (a and b) respectively improved the elastic modulus by 6% and 7% over the control mix. 6. the development of several models from laboratory test results obtained in this work can be used to evaluate the effect of different variables on the performance related to vertical strain of modified mixtures. 7. it is recommended to evaluate the effect of optimizing fiber properties (i.e., fiber diameter, length, surface texture, etc.) on the performance of dense graded mixtures. laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 430 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 acknowledgement the author is grateful for the support of highway and transportation engineering department /college of engineering/ university of al-mustansiriyah and civil engineering department /college of engineering/ baghdad university. references 1. annual book of astm standards, section 4, construction, volume 04.03, road and paving materials; pavement management technologies, american society for testing and materials, philadelphia, pa., 1996. 2. british standard, bs 1881: part 203: 1986. 3. "general specification for roads and bridges", section r9, hot –mix asphalt concrete pavement, revised edition 2003. 4. muncy, h.w., king, g.n, and prudhomme, j,b, "improved rheological properties of polymer –modified asphalts", asphalt rheology: relationship to mixture, astm stp 941, o,e, brisoe, ed, american society for testing and materials ,philadelphia, pp(146-165), 1987. 5. murat, m., "hydration reaction and hardened of calcined clays and related minerals cement and concrete", research, vol.3, no.2, 1983, pp (259-266). 6. rajas, j., nazarian, s., tandon, v., and yaun, d, “ qualitymanagement of asphaltconcrete layers using wave propagation techniques”. jornal of association of asphalt paving technologists, vol.68, 1999. 7. saeed ghaffarpour jahromi and ali khodaii (2000), "carbon fiber reinforced asphalt concrete", the arabian journal for science and engineering, vol.33, no. 2b, pp (12971304). 8. serfass, j.p.; j. samanos. (1996) “fiber-modified asphalt concrete characteristics, applications and behavior”, journal of the association of asphalt paving technologists, vol. 65, pp (193-230). 9. thomas d. white, professor of civil engineering, purdue university, and haiming huang, research assistant, purdue university, "effect of fibers on hma performance". trb, national research council, washington, d.c., 1999. table 1 physical properties of polypropylene fiber. form virgin polypropylene fiber specific gravity 0,91 gm/cm³ fiber thickness (18 and 30) microns young modulus (5500-7000) mpa tensile strength 350 mpa melting point 160 cº fiber length 19 mm ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 431 table 2 descriptive statistical models. mix case model adj. r 2 see loading mix = 10 4.16 * (t) 1.337 * (t) 0.187 * (1+ppf) 0.849 * (ed) -1.328 0.930 0.077 a unloading log ( mix) =0.132+ 0.014 (t) 0.395 (ppf) 0.001 (t) 0.95 0.042 loading mix = 10 9.253 * (t) 1.056 * (t) 0.167 *(1+ppf) 0.847 *(ed) -2.464 0.899 0.077 b unloading mix = 1.601 +0.065 (t) + 1.744 (ppf) 0.011 (t) 0.55 0.64 figure 1 polypropylene fiber configurations. figure 2 polypropylene fiber configuration that is used in this study. laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 432 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 figure 3 specification limits and selected gradation of aggregate, type (a). figure 4 specification limits and selected gradation of aggregate, type (b). ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 433 figure 5 effect of asphalt cement content and polypropylene content on marshall properties of dense graded mixtures type (a). laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 434 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 figure 6 effect of asphalt cement content and polypropylene content on marshall properties of dense graded mixtures type (b). ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 435 figure 7 effect of testing temperature on indirect tensile strength of dense graded mixtures type a. figure 8 effect of testing temperature on indirect tensile strength of densegraded mixtures type b. laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 436 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 figure 9 effect of polypropylene content on straintime relationship. figure 10 effect of polypropylene content on straintime relationship. figure 11 effect of polypropylene content on straintime relationship. ahmed i. ahmed al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 437 figure 12 effect of polypropylene content on straintime relationship. figure 13 effect of polypropylene content on straintime relationship. figure 14 effect of polypropylene content on straintime relationship. laboratory investigation into the impact of polypropylene fiber content on temperature susceptibility of dense graded mixtures 438 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 424-438, year 2012 figure 15 effect of polypropylene content on elastic modulus of asphalt mixtures 0 0.1 0.2 0.3 creep is an important measure of modified asphalt performance, its ability to elastically recover deformation. since asphalt pavement are designed to be flexible, they must quickly return to their original configuration after loading (muncy, and prudhomme, 1987). the diametric – indirect tensile creep test has been used to determine the vertical strain of asphalt mixtures by measuring strain – time values. this test is performed on marshall specimens at corresponding optimum asphalt content (oac) for each polypropylene content under a constant stress of (0.1mpa). the specimen is loaded to static stress of 0.1 mpa for 1 hour, and the deformation is recorded at certain time increments of (0.1 , 0.25 , 0.5 , 1 ,2 ,4 ,8 ,15 ,30 ,45 ,and 60 min). the load is then released, and the recovered strain for 1 hour is recorded, at the same periods. statistical models for creep test � figure 3 specification limits and selected gradation of aggregate, type (a). � figure 4 specification limits and selected gradation of aggregate, type (b). \(microsoft word \\323\\312 \\325\\317\\3542011 \\343\\344\\326\\317\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 1 تصميم برنامج حاسوبى لقياس كفاءة اداء المعامل التابعة لقطاع التشييد صدى عبد الخالق الياسرى جامعة القادسية/قسم الهندسة المدنية/كلية الهندسة الخالصة ولغرض تحقيق قياس كفاءة اداء المعاملليهدف البحث الى اتباع المنهج العلمي في استخدام الحاسوب قد تم بناء برنامج حاسوبي لقياس كفاءة اداء المعامل التابعة لقطاع التشييد وفقا لمجموعة فف البحث هد وقد تم تطبيق ذلك على معمل سمنت الكوفة وذلك بقياس ، مؤشرات مستحصلة من الدراسة النظرية للموضوع بينها انخفاض نسبة االنتفاع ومن خالل ذلك تم التوصل الى مجموعة استنتاجات من، ٢٠٠٧كفاءة اداءه لسنة فيما لو تم تجهيز االخير بالطاقة الكهربائية بشكل مستمر المكانية % ٢٧.٥بالطاقة المتاحة للمعمل الى وهي نسبة فاعلية خط انتاجي واحد يعمل حاليا % ٩٠.٥االرتفاع بهذه النسبة الى للقيام البرامج الحاسوبيةستفادة من امكانيات وفي النهاية تم التوصل الى مجموعة توصيات من بينها اال كما تم التوصل الى . بعملية قياس كفاءة االداء للمعمل فصليال وسنويا لتقويم االداء بتجاوز نقاط الضعف .مقترحات لبحوث مستقبلية measurment the performance sufficeincy in the factories of construction field sada abdul khaliq alyasri college of engineering abstract the establishment manger in need in this time for following the scientific study to evaluate the duty of the factory . this research aims to study the status of the factories which belong to construction fied in iraq , as the systeme of oplication of ideal production mangment and evaluat the working duty of those fatories . to achieve the aim of research , we design a computer program for measuring working duty of factory which belong to construction field . also we discover that some factors controlled the process of production specifying in the factories which belongs to construction field in iraq and these factors are (supplying by the electricity in continual way which gave warranty to continual of production process . the results of this program has been designed to measure the work duty of the factory which belongs to construction field according to agroup of pointer which has been resulted from the theortical study of the subjcet . and that has been applicated in cofa cement factory by measuring work duty of 2004 through that has been reached to some results from these the low of benfit scription of free enargy of the factory to 27.5% . but if the factory has been supplied by the al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 2 electricity in continual way so the scription would rise to 90.5% and this the duty scription of one production line which is working now . at the end we have been reached to some advices, from these measure the work duty of the factory , seasonly and yearly to evalute the working passing the point of weekness . also has been reached to some sugestions to next resarch . المقدمة دارسين في تخصصات يمثل مجال ادارة االنتاج احد المجاالت االساسية لتقديم فرص العمالة الخّالقة امام ال واع المشروعات حيث يمثل المشتغلون بهذا المجال عصب النظام االنتاجي في جميع ان، االنتاج والهندسة اصبحت تطبيقاته العلمية جزءا مهما في مجاالت نظم المعلومات ، ونتيجة لظهور الحاسوب .الصناعية والخدمية فاءة أداء المعامل التابعة لقطاع التشييد لمعرفة مدى نجاح ضرورة وجود مقياس لكلذا من مبررات البحث االدارية قياس كفاءة األداء في تلك المعامل بحيث يمكن يهدف البحث الى حيث .نشأة او المعمل في تحقيق األهدافالم الركون الى هذه القياسات في تقدير واعتماد أرقام تمثل حدود األداء االعتيادي واإلنتاجية الالزمة كمراجع .مال السيطرة والرقابة ولغرض االستفادة من ذلك عند حساب تكاليف اإلنتاج الع literature survey:الدراسات السابقة بتطبيق برامج خاصة ببحوث العمليات لتخطيط ]١[ richard b . chaseقام ١٩٩٠في عام وهي دراسة ، رات قياس االنتاجية داخل تلك المعاملاالنتاج في المعامل االنتاجية الخدمية كما تم تحديد مؤش . نظرية وتطبيقية على احد المعامل الخدمية بتطبيــق االســاليب الرياضـية لتحديــد العـدد االمثــل لالداريــين ]٢[قــام عــادل عبــد الملــك ١٩٩٣فـي عــام عـــداد االفـــراد الضـــرورين فعـــًال لـــالدارة والمشـــرفين فـــي المنشـــأت االنتاجيـــة طبقـــًا لهياكلهـــا النتنظيميـــة بغيـــة تحديـــد ا واالشــراف وقــد دعــا الباحــث فــي النهايــة أدارات المعامــل بــان تتجــه الــى اســتخدام اســاليب التخصــيص فــي بحــوث . بغية الخروج بالنتائج السريعة واالستفادة من تقنيات الحاسوب في هذا المجال –البرمجة الخطية –العمليات بدراسة اسلوب ادارة وتحديد طاقات b.adeso and pilar gonzalez [3]قام ٢٠٠٢وفي عام المعامل المسموح بها وفقا لما متاح لها من موارد وقد جرت الدارسة باطارين نظري وتطبيقي على احد معامل الخدمات الصناعية وقد اوصى الباحثان في النهاية الى اتباع وتطبيق برامج الحاسوب المصصمة لخدمة مثل .لمواضيع من اجل الحصول على تحليل اكثر دقة ووضوح هذه ا فهوم تقويم وكفاءة االداء م ال يمكـــن الي شـــركة ان تســـتغني عـــن تقـــويم االداء ســـواء كـــان علـــى مســـتوى الهيكـــل التنظيمـــي والخطـــط تاجيًا واالهــداف أوعلــى مســتوى االفــراد العــاملين فيهــا فعلــى مســتوى الشــركة يعــد قيــاس كفــاءة االداء فحصــًا اســتن شامًال للهيكل التنظيمـي للمنشـأة والخطـط واالهـداف واسـتغالل المـوارد الماديـة والبشـرية والماليـة المتاحـة مـن اجـل al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 3 الحكــم علــى مســتوى النشــاط فيهــا وقــدرتها علــى اداء وظائفهــا فضــًال عــن تقــويم النتــائج النهائيــة كحصــيلة للجهــود . ]٤[المبذولة من قبل المنشأة في ممارسة وظائفها امـا علـى مسـتوى تقـويم اداء العـاملين فـي المنشـأة فـأن مفهـوم تقـويم االداء يعبـر عـن النظـام الـذي يســاعد في قياس وتقويم العالقة بين كفـاءة اداء الفـرد لواجبـات ومهـام الوظيفـة التـي يشـغلها وكـل مـن سـلوك ومقـدرة الفـرد درجـة االنجـاز الفعليـة بمـا يسـاعد علـى معرفـة جوانـب على االداء االفضل والناتج المتحقق طبقًا لمسـتوى االداء و القوة والضعف فـي االداء الماضـي وتحديـد كيـف يمكـن تجنـب جوانـب الضـعف واسـتثمار جوانـب القـوة فـي الوقـت الحــالي وفــي المســتقبل للوصــول الــى اعلــى درجــات كفــاءة االداء بمــا يعــود بالفائــدة علــى الفــرد والمنشــأة والمجتمــع ]٥[ . هوم كفاءةاالداء على ثالثة ابعاد تشكل بمجموعهـا نموذجـًا متكـامًال لقيـاس وتقـويم كفـاءة االداء ويشمل مف : ]٦[الكلية في المنشأة وهذه االبعاد هي أي مدى كفاءة المنشأة للحصول على الموارد االقتصادية بمستوى مناسب من الجودة وبأقل -:االقتصاد -:اوًال . قدر ممكن من الكلفة أي محاولة تحقيق اقصـى مخرجـات ممكنـة مـن اسـتخدام ( وهي تكون اما بتعظيم المخرجات -:الكفاءة -:يًا ثان أي محاولة استخدام اقل قدر ممكن من المدخالت المخصصـة لمسـتوى ( او تقليل المدخالت ) مدخالت معلومة . معين من المخرجات للوصول الى اعلى المخرجات ي تطابق المخرجات مع الخطط الموضوعة التي ترغب المنشأة بتحقيقها أ -:الفاعلية -:ثالثًا نســـبة المخرجـــات الـــى مـــا تحتاجـــه مـــن مـــوارد ســـواء كانـــت ماديـــة او بشـــرية مـــن البيئـــة انـــه حيـــث تعـــرف الكفـــاءة ب . ]٧[المحيطة بها كمدخالت العملية االنتاجية ات وذلــك مــن خــالل انجــاز الكثيــر بأقــل مــا يمكــن كمــا تعــرف علــى انهــا العالقــة بــين المــدخالت والمخرجــ ، وكــل تلــك التعــاريف تصــب فــي االســتخدام االمثــل والعقالنــي للمــوارد المتاحــة ســواء اكانــت ماديــة او بشــرية ]٨[ .وصوًال الى المخرجات الجيدة بالكم والنوع -:اهمية قياس كفاءة االداء . ]٩[االداء على مستوى المنشأة واالفراد وكمايلي يمكن االستنتاج مما سبق ذكره اهمية قياس كفاءة . توفير مقياس لمدى نجاح المنشأة في تحقيق اهدافها .١ تحقيق اكبر قدر من االنتاج بأقل الكلف من خالل التخلص من عوامل الهدر والضياع في الوقت والجهد .٢ . والمال يط والرقابــــة واتخــــاذ القــــرارات اســــتنادًا تــــوفير المعلومــــات للمســــتويات االداريــــة المختلفــــة الغــــراض التخطــــ .٣ . الىالحقائق العملية والموضوعية . المساعدة في خلق روح التنافس بين االقسام وادارات المشاريع المختلفة مما يدفعها الى تحسين ادائها .٤ al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 4 يفيـــد فـــي الكشـــف عـــن العناصـــر الكفـــوءة لتكريمهـــا و الكشـــف عـــن العناصـــر التـــي تحتـــاج الـــى المســـاعدة .٥ . وض بادائها الى المستوى الطموح وتحديد العناصر المتكاسلة اوغير المنتجة لالستغناء عنها للنه . المساعدة في ايجاد نظام سليم وفعال للمكافأت والحوافز التشجيعية .٦ سمات مؤشرات قياس كفاءة االداء ـ: ]١٠[االتية يجب ان تتسم بالسمات لكي تحقق مؤشرات قياس كفاءة االداء الغرض المطلوب منها الوضوح وعدم االتسام بالتعقيد الذي يبعدها عن تحيق الغرض المنشود منها لذا وجب التحديد النوعي .١ . لمؤشرات قياس كفاءة االداء . قابليتها لقياس الظواهر المراد قياس كفاءة ادائها .٢ الحقيقــي علــى التماثــل ارتباطهــا بأعمــال المنظمــة المــراد قيــاس كفــاءة ادائهــا لكــي تكــون لهــا القــدرة .٣ الوجه النشاطات الهامة التي تقوم بها المنظمة ، وبعبارة اخـرى تحديـد المؤشـرات بشـكل اجمـالي ومـن . ثم اختبار المؤشرات المناسبة للمنظمة معرفــة مــدى عالقتهــا بأهــداف المجتمــع وخطــط التنميــة االقتصــادية والتــي مــن خــالل هــذه المؤشــرات .٤ . تحققها -:قويم االداء خطوات ت ان اتباع خطوات منطقية ومتسلسلة في تقويم االداء له جانب كبير من االهمية في تجنب تداخل . العوامل العديدة واالهداف التي سبق االشارة اليها وعلى الرغم من اختالف الباحثين في عدد الخطـوات التـي تتكـون منهـا عمليـة التقـويم اال انـه هنـاك سـت خطـوات : ]١٠[مرتبة كما يأتي اساسية -:وضع توقعات االداء ـ ١ بين المدير (هي اولى الخطوات في تقويم االداء حيث تتم بالتعاون بين مدير المشروع مع العاملين أو ويتفـــق علـــى وصـــف المهـــام المطلوبـــة والنتـــائج التـــي يـــتم تحقيقهـــا واالوليـــات فـــي اســـتخدام العـــاملين )والمرؤوســـين . هذا االتفاق االساس في ادارة عملية تقويم االداء والوقت لكي يكون -:مراقبة التقدم في االداء ـ ٢ ان عملية االداء عملية مستمرة وليست موسمية ومن ثم فأن مراقبة االداء مفيدة في معرفـة كيـف يعمـل بالعمـل وهـل تـم من يكون في تنفيذ العمـل فـي ضـوء توقعـات المعـاير المحـددة وتعطـي مؤشـرات عـن كيفيـة القيـام وضع الخطط بشكل جيد واالتصاالت والمواد هل تم تنظيمهـا بشـكل جيـد ، ومـن المالحـظ ان هـذه النقطـة مهملـة .في الحياة العملية حيث تتم التقويمات في نهاية الفترة al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 5 -:تقويم االداء ـ ٣ ان يكـون غايـة فـي حـد ذاتـه بـل ان الخطوة الثالثة هي القيام بتقـويم االداء ، ان تقـويم االداء ال يمكـن وسيلة يمكن بواسطتها الحصول علـى تعليمـات تفيـد االدارة العليـا فـي اتخـاذ القـرارات المختلفـة وتأكيـد مالئمـة هـذه القــرارات كمــا انهــا تفيــد العــاملين عــن طريــق ايجــاد القاعــدة لتغذيــة عكســية موضــوعية والحيلولــة دون تجــاهلهم مــن . قبل االدارة -:ية العكسية التغذ ـ ٤ من يتم تقويمه يحتاج الى تغذية عكسية بشأن ادائه من اجل معرفـة مـدى تقدمـه فـي العمـل مـع مـا هـو متوقع منه من قبل االدارة وبغياب التغذية العكسية قد يتوصل الشخص الى نتائج غير دقيقة االمر الـذي يـنعكس تها البد ان يفهم الشـخص الـذي يـتم تقويمـه المعلومـات على ادائه بشكل مباشر ولكي تحقق التغذية العكسية فعالي . ويتقبلها ويستفيد منها -:اتخاذ القرارات االدارية ـ ٥ وتتمثــل هــذه القــرارات بنــواحي عديــدة مثــل النقــل واعــادة التكليــف الــوظيفي والترقيــة والحــوافز او تنزيـــل . الدرجة وما شابه ذلك -:وضع خطط تطوير االداء ـ ٦ ا الخطوة االخيرة فهي وضع الخطط لتطوير وتحسين االداء وتبرز اهمية هذه الخطوة عندما ال تقبل ام . النتائج العلمية فيها مع ما خطط لها مسبقًا -:مؤشرات كفاءة االداء للمعامل االنتاجية االنشائية ـ: يمكن قياس كفاءة اداء أي منشأة من خالل المؤشرات التالية ]١٢[،]١١[اءة االدارةمؤشرات كف يقـيس هـذا المؤشـر المـّدة التـي اسـتغرقها تنفيـذ العمـل فعـًال الـى المـدة -:مؤشر مدة التنفيذ ضـمن الخطـة .١ المخططــة لالنجــاز وكلمــا انخفضــت هــذه النســبة عــن واحــد كلمــا اشــارت الــى عامــل ايجــابي وجهــد فعــال -:لالدارة والعاملين حيث ٢. مدة االنجاز الفعلي )١( = مدة التنفيذ ضمن الخطة مؤشر المدة المخططة لالنجاز -: مؤشر التنفيذ ضمن الكلفة. ٣ -:ساب هذا المؤشر كما يأتي ويمكن ح كلفة االعمال المنجزة )٢( = التنفيذ ضمن الكلفة المخططة النجاز المشروع مؤشر al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 6 كلفة االعمال المخطط النجازها ان انخفــاض نســبة هــذا المؤشـــر عــن واحــد يعــد عامـــل ايجــابي ودلــيًال يعبــر عـــن كفــاءة االدارة فــي تقلــيص كلفـــة . االعمال المنجزة كلفة االنتاج الفعلي )٣( %١٠٠× = أو مؤشر الكلفة الفعلية لالنجاز من قيمة االنتاج االنتاج الفعلي قيمة تجات مقارنة بكلفتها نيعطي هذا المؤشر توضيحًا حول سعر الم -: مؤشر نوعية العمل المنجز. ٤ ان لهذا المؤشر اهمية في معرفة مدى تحقيق المنتوج للجودة والقبول وارتفاعه دليل على التنفيذ الجيد لعمل المرفوض كلفة ا )٤( % ١٠٠× -١% = مؤشر النوعية الكلفة الكلية عدد الفحوصات المختبرية الناجحة )٥( % ١٠٠× % = و مؤشر النوعية ا عدد الفحوصات المختبرية الكلية ان ارتفاع نسبة هذا المؤشر يعد دليًال ايجابيًا للتنفيذ بنوعية جيدة ي الموادمؤشر نسب عدم الهدر ف. ٥ -:االمثل ان هذا المؤثر يعطي دليًال على حرص االدارة وكفاءتها في استغالل الموارد بالشكل كلفة المواد المستخدمة )٦( % ١٠٠ × = عدم الهدر في المواد مؤشر كلفة المواد المخمنة )٧( %١٠٠× )نسبة التلف -١= ( نسبة عدم الهدر كمية االنتاج التالف )٨( %١٠٠× -١= ؤشر عدم الهدر م كمية االنتاج الكلي في االنتاج . المتاحة ان انخفاض هذه النسبة عند واحد يعطي داللة ايجابية عن كفاءة االدارة لالستغالل االمثل للموارد . ]١٢[، ]١١[ ة العملمؤشرات كفاء مؤشر كفاءة العمل الى مجموع العاملين. ١ al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 7 قيمة االنتاج باالسعار الثابتة )٩( = مؤشر كفاءة العمل عدد العاملين مؤشر العمل الى مجموع العالمين الفنيين . ٢ قيمة االنتاج باالسعار الثابتة )١٠( = مؤشر كفاءة العمل عدد العاملين الفنيين مؤشرات كفاءة المكائن والمعدات مصاريف الصيانة الفعلية )١١( = مؤشر نسبة مصاريف الصيانة. ١ مصاريف الصيانة المخططة تنفيذ خطة الصيانة من خالل مقارنة المصـاريف الفعليـة مـع مـا هـو مخطـط حيث يقيس هذا المؤشر فاعلية .لها مصاريف الصيانة الفعلية )١٢( %١٠٠× = مؤشر نسبة مصاريف الصيانة من قيمة االنتاج االنتاج الفعلي قيمة مؤشر نسبة فاعلية الفرن او الخط االنتاجي -٢ :حيث يوضح هذا المؤشر فاعلية انتاجية الفرن او الخط االنتاجي ويقاس بالمعادلة التالية عدد االفران او الخطوط الصالحة لالشتغال/ قيمة االنتاج الفعلي او كميته )١٣( = نسبة فاعلية الفرن او الخط االنتاجي لالشتغالعدد االفران او الخطوط المخططة / قيمة االنتاج المخطط او كميته مؤشر نسبة االنتفاع بالطاقة. ٣ حيث تقيس هذه النسبة مدى االنتفاع من الطاقة المتاحة الطاقة الفعلية )١٤( % ١٠٠× = نسبة االنتفاع بالطاقة الطاقة المتاحة -:مع العلم أن متاحةعلى مدى االنتفاع بالطاقة ال حيث ان ارتفاع هذه النسبة يعد دليًال ايجابياً al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 8 :]٣[ الطاقة الفعلية -أ . هي كمية االنتاج الفعلي الذي تم تحقيقه في الوحدة االنتاجية خالل فترة زمنية معينة : ]٣[الطاقة المتاحة -ب ي اعلى كمية انتاج موصوف ممكن تحقيقه بتشغيل مكائن المشروع بوصفها القائم بأقصى ساعات العمل في ه اليـــوم واليـــام االشـــتغال المتاحـــة فـــي الســـنة ، وعلـــى افتـــرض تـــوفير مســـتلزمات االنتـــاج مـــن عمالـــة مدربـــة ومـــواد . بالمواصفات المطلوبة مؤشر كفاء االجور المدفوعة . شر مدى كفاءة استغالل االجور المدفوعة الى العاملين ، فأرتفاعه يعد مؤشرًا ايجابيًا حيث يوضح هذا المؤ مجمل قيمة االنتاج )١٥( % ١٠٠× = انتاجية االجور مجمل قيمة االجور المدفوعة :علما ان )١٦( السعر المخطط xالطاقة االنتاجية المخططة =قيمة االنتاج المخطط )١٧( السعر المخطط xالطاقة االنتاجية الفعلية =قيمة االنتاج الفعلى بعــد ان تــم التعــرف علـــى األســس والمؤشــرات النظريـــة الخاصــة بقيــاس األداء والعوامـــل التــي تــؤثر علـــى تحديد اإلنتاج األمثل ، كان البد من التعرف على واقع حال تطبيق تلـك العوامـل والمؤشـرات فـي المعامـل التابعـة ًا بارزًا في سـتراتيجية التنميـة الصـناعية وبمـا ان كـل لقطاع التشيد في القطر حيث تحتل الصناعة اإلنشائية موقع من شركات االعمار واالسكان وشركات الصناعة والمعادن تعتمد على اإلمكانيات الذاتية من الموارد المتوفرة في القطر كمواد اولية في معاملها ذات اإلنتاج اإلنشائي االمر الذي يجعل هذه الشركات تتميز بدورها الهام في دعم حــث باالقتصــاد الــوطني ، ومــن اجــل الوصــول الــى تحديــد حجــم اإلنتــاج األمثــل فــي معامــل قطــاع التشــيد ، قــام ال . بدراسة ميدانية تم من خاللها الحصول على البيانات العملية الالزمة النجاز البحث بناء برنامج حاسوبي لقياس كفاءة اداء معامل قطاع التشييد يــه مــن هــذا البحــث فقــد استخلصــت مجموعــة مــن المؤشــرات التــي يمكــن مــن خاللهــا علــى ضــوء مــا تــم التوصــل ال قياس كفاءة اداء المعامل التابعة لقطاع التشيد ، ذلك ان كل معمل من المعامل يكون تابعـًا الـى شـركة او منشـأة . ة لها وحيث ان االخيرة تقوم سنويًا بقياس كفاءة ادائها ككل وليس قياس كفاءة اداء المعامل التابع al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 9 في حساب وقياس كفاءة اداء المعامل التابعة حددةلقد تم بناء برنامج حاسوبي اعتمد المؤشرات الم . لقطاع التشييد في العراق ، اضافة الى تناول مراحل عمل البرنامج من تحديد لمواصفاته وهيكليته مواصفات البرنامج الحاسوبي ( بأســـتخدام احـــدى لغـــات قواعـــد البيانـــات المتطـــورة وهـــي لغـــة تـــم بنـــاء البرنـــامج لتنفيـــذ متطلبـــات البحـــث visual basic ( المتالكها امكانيات برمجية متطورة تمتاز بالسـرعة والدقـة فـي ايصـال المعلومـات الخاصـة -:بالبرنامج الى المستخدم اثناء التنفيذ باالضافة الى ذلك فقد امتاز البرنامج بالمواصفات التالية يسهل العمل عليها كونه يتعامل مع اللغـة العربيـة باالضـافة الـى وجـود عبـارات الداللـة صمم بطريقة • . لتوجه المستخدم ومساعدته يمكــن للبرنــامج بوقــت قليــل جــدًا ان يعطــي معلومــات وبيانــات دقيقــة جــدًا ومفصــلة مــن قيــاس كفــاءة • ليدويــة التــي تحتــاج الــى وقــت االداء الي معمــل اعتمــادًا علــى المؤشــرات المنتخبــة مقارنــة بالطريقــة ا . طويل والنتائج قابلة للخطأ ان مســـتخدمي البرنـــامج ال يحتـــاجون الـــى معرفـــة الصـــيغ الرياضـــية حيـــث يمكـــنهم الوصـــول الـــى النتـــائج • الخاصــة بقيــاس االداء بمجــرد ادخــال البيانــات المثبتــة فــي اســتمارة قيــاس كفــاءة االداء وتشــغيل البرنــامج .ة لكل مؤشر من المؤشرات المعينة الذي يقوم بحساب النسب هيكلية البرنامج الحاسوبي حسب ما تم تحديده في البحث يمكن تحديد الهيكلية االساسـية المتسلسـلة للوصـول الـى قيـاس كفـاءة اداء ، وهــذه الهيكليــة يمكــن برمجتهــا علــى الحاســوب باســتخدام ) ١( الشــكل عــة لقطــاع التشــيد كمــا فــي المعامــل التاب . لغات البرمجة احدى كيفية عمل البرنامج وادخال البيانات .performanceيتم تشغيل البرنامج بعد تنصيبه على الحاسبة بالنقر على اسم البرنامج . ١ سوف تظهر على الشاشة مجموعة من البيانات والحقول الخاصة بالمعمل المراد قياس كفاءة . ٢ .اداءه الموجـود اسـفل ) view result( بيانات ثم تنفيذ البرنامج بالنقر على المربـع يتم امالء الحقول السابقة بال. ٣ .واجهة ادخال البيانات للحصول على النتائج تظهر لنا مجموعة الحقـول الخاصـة بنتـائج البرنـامج واذا اردنـا طباعـة النتـائج فاننـا نقـوم بـالنقر بواسـطة الفـأرة . ٤ .سفل واجهة اخراج البيانات الموجود في مربع ا) print result( على back( ير في أي من المدخالت فاننا نرجع الى واجهة ادخال البيانات بالنقر على المربع يعندما نريد التغ. ٥ to input form ( الموجود في مربع اسفل الشاشة. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 10 ) كحالة دراسية ( تطبيق البرنامج الحاسوبي على معمل سمنت الكوفة ادخال البيانات خــالل المســـح والدراســة الميدانيـــة والمقــابالت الشخصـــية لمعمــل ســـمنت الكوفــة ، تـــم الحصــول علـــى مــن كفـاءة اداء المعلومات المبينة الحقـًا والتـي تعبـر عـن البيانـات التـي يمكـن ادخالهـا الـى البرنـامج الحاسـوبي لقيـاس والمعلومـات ) ٢٠٠٦( ختيـرت سـنة يوضح كيفية ادخال البيانات الـى البرنـامج حيـث ا ) ٢(والشكل رقم المعمل . لكون المعمل كان يعانى من بعض المشاكل ان ذاكالخاصة بها لقياس كفاءة اداء المعمل في تلك السنة بيانات المعمل والتـي سـوف يحسـب البيانات المطلوب ادخالها والخاصة بمعمل سـمنت الكوفـة ) ١(الجدول رقم يبين . ٢٠٠٦لسنة من خاللها كفاءة اداء المعمل والمناقشة النتائج النهائية والـذي يبـين نتـائج الحاسـبة الخاصـة بقيـاس كفـاءة اداء معمـل سـمنت الكوفـة ) ٣(الشكل رقم من خالل مالحظـة دينار في حين كانت قيمة االنتاج ١٦٣١٥٢٠٠٠٠٠٠كانت قيمة االنتاج المخطط ) ٢٠٠٦( نجد انه في سنة ويرجــع ســبب انخفــاض قيمــة االنتــاج الفعلــي مقارنــة بــالمخطط النخفــاض كميــة دينــار ٤٩٢٢٦٥٤٠٠٠٠الفعلــي كـــاناالنتـــاج الفعلـــي بســـبب ظـــروف المعمـــل الـــذي يعـــاني مـــن االنقطـــاع المســـتمر فـــي التيـــار الكهربـــائي نتيجـــة ما ي يتعرض له البلد من ظروف والتي تعكس اثارها على اقتصاده ، اضافة الى انعدام وجود المولدات الضـخمة التـ تكفــي لتشــغيل مثــل هكــذا معمــل وتعاقــد المعمــل منــذ بدايــة الســنة علــى تجهيــزه بالمولــدات مــن قبــل شــركات اجنبيــة وتــأخر تنفيــذ ذلــك ممــا ادى الــى تشــغيل خــط واحــد لالنتــاج بــدل ثالثــة خطــوط وتــرك خــط اخــر للمعمــل فــي حالــة . عطل في الخط نتيجةتوقف التلــف فــي المــواد االوليــة المســتخدمة اضــافة الــى نســب التلــف فــي كــذلك فــأن المعمــل يقــوم بعمليــة حســاب نســب % ٩٥(، لـذا نجـد ان نسـبة عـدم الهـدر المحسـوبة ) سـمنت ( والمنتـوج النهـائي ) كلنكـر ( المواد نصف مصنعة . للخط انتاجى واحد) دخـول المـواد اما بالنسبة لجودة نوعية االنتاج فأن المنـتج يخضـع لفحوصـات مختبريـة عديـدة ابتـداءًا مـن الخاصـة بالجهـاز المركـزي ١٩٨٤لسـنة ٥االولية وحتى خروج المنتج النهائي ووفقًا لحدود الواصفة العراقيـة رقـم قســم وهـذه الفحوصــات تجـرى داخـل المعمــل مـن قبـل والمعتمـدة فــى المعمـل للتقيـيس والسـيطرة النوعيـة فــي العـراق مـع الحـدود المسـموح الفحوصـات مقارنة نتـائج بعد% ١٠٠اج هي جودة نوعية االنت فقد وجد انالسيطرة والرقابة ١٠بهـا ضــمن المواصــفة المشــار اليهــا ســابقًا علمــًا ان عــدد الفحوصــات المختبريــة الخاصــة بــالمنتج النهــائي تبلــغ ).جاءت هذه النتيجة وفقا للفحوصات الداخلية فى المعمل و (فحوصات المعمــل ان نســبة الكلفــة الفعليــة النتــاج الســمنت مــن قيمــة ايضــًا نــرى مــن خــالل نتــائج قيــاس كفــاءة اداء ويرجـع هـذا االرتفـاع ،وهي نسبة بسيطة جدًا وهذا يدل على ارتفاع سعر السمنت مقارنـة بكلفتـه% ١٢.٤االنتاج al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 11 الى سياسة الوزارة والشركة القاضية بتسعير المنتج وفقًا لما ترتأيه اضافة الى تشغيل عدد كبير من العمـال داخـل . المعمل مما يترتب عليه دفع اجور كبيرة لهم لمعمـل لـو تـوفرت وهي نسبة قليلة مقارنة بالطاقة المتاحة ل% ٢٧.٩ بالطاقةكذلك نجد ان نسبة االنتفاع وهـــذا يشـــير الـــى مـــدى ظـــرورة تـــوفر المولـــدات التـــي تمـــد المعمـــل بالكهربـــاء والتـــي مـــن الممكـــن الطاقـــة الكهربـــائي % . ٩٠سبة االنتفاع بالطاقة الى بواسطتها االرتفاع بن ومــن المؤشــرات المحســوبة ايضــًا هــو مؤشــر كفــاءة العمــل والــذي يحســب قيمــة انتاجيــة كــل عامــل داخــل المعمــل .خالل الفترة المعدة خاللها القياس طن لكل عامل وهذا يعني ان كمية انتاج كل عامل ) ٢١٥,٧٧(وهنا نرى ان مؤشر كفاءة العامل تساوي اضــافة الــى ذلــك نجــد ان نســبة فاعليــة طــن لكــل عامــل لهــذة الســنة ٢١٥٠,٧٧تســاوي) نتاجيــة العامــل الواحــد ا( وهي نسبة جيدة وتعطـي مؤشـر جيـد لمـدى اسـتغالل الطاقـة المتاحـة للخـط الواحـد نسـبتًا % ٩٠,٥الخط االنتاجي . الى عدد الخطوط المشتغلة وهي نسبة جيدة وتشير % ٨٦نرى ان هذه النسبة قد بلغت كذلك تبين النتائج نسبة فاعلية الفرن ، حيث . الى مدى تحقيق انتاجية جيدة للفرن مقارنة مع ما هو مخطط له من قيمة االنتاج وهـي نسـبة بسـيطة جـدًا لكـن لهـا اهميـة كبيـرة % ٢,٦٤٨وتشير نسبة مصاريف الصيانة الى نوات الســابقة وعنــد تــوفر الطاقــة الكهربائيــة بالشــكل فــي تحقيــق اكبــر انتــاج ممكــن ذلــك ان المعمــل فــي بعــض الســ مــن تلــف بعــض االجــزاء فــي االالت االصــلية المنشــأ ممــا ادى الــى تضــيعها محليــًا لتعــويض عــانىالمســتمر قــد التالف ولكن ليس بالكفاءة والجودة االصلية لــك االجــزاء وهنــا وهــذا ترتيــب عليــه توقــف االنتــاج فــي بعــض الخطــوط لعــدة ايــام نتيجــة معــاودة تلــف ت نشير الى ظرورة توفير االجزاء االحتياطية االصلية لمكائن المعمل وخاصة عند وجود تلف مستمر لبعض اجزاء االالت لتالفـــي أي توقـــف او انقطـــاع فـــي االنتـــاج وبالتـــالي تحقيـــق اكبـــر قـــدر ممكـــن مـــن االنقطـــاع مـــن الطاقـــة . االنتاجية المتاحة فع للعاملين داخل المعمل فان البرنامج قـد قـام بقيـاس مؤشـر كفـاءة االجـور ولقياس كفاءة االجور التي تد كقيمــة )دينــار ٦٠(وهــذا يعنــي ان لكــل دينــار يصــرف كــأجور يقابلــه )دينــار ٦٠( المدفوعــة حيــث وجــد انــه يســاوي . لالنتاج -:االستنتاجات والتوصيات والدراسات المستقبلية كما التوجد مؤشرات قياسية متبعة لقياس كفاءة مل قطاع التشييد معايير لالنتاجية داخل معا اتباععدم .١ . اداء العاملين وتقويماداء المعامل االنتاجية لالستفادة منه في في بعض المعامل السابقة للسنواتالنتاج كمية ايحفظ ل دقيق عدم وجود توثيق .٢ . المعمل يقتصر ذلك فقط على الشركات التابع لهابل البحوث al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 12 مدراء المعامل على اطالع كامل بالصالحيات المخولة لهم من قبل الشركة فيما يخص االنتاج المخطط اغلب والفعلي والمتاح من خالل تطبيق البرنامج الخاص بقياس كفاءة االداء على معمل سمنت الكوفة وجد ان انخفاض قيمة .١ .على اقتصاد البلد االنتاج الفعلي مقارنة بالمخطط النخفاض كميته والتي تعكس اثارها وهذا يعطي دليال على كون سعر االسمنت مرتفع %١٢,٤مؤشر كلفة االنجاز من قيمة االنتاج تساوي .٢ بسبب كون المواد االولية والناتج النهائي % ٩٥اما نسبة عدم الهدر فقد بلغت .حاليا مقارنة بكلفته . ي الى تطاير غبار كثير منه والذي يؤد) رياح وغيرها(يتعرض الى ظروف الجو من ) سمنت( بالنسبة للمعمل ككل في حين بلغت نسبة فاعلية الخط % ٢٧,٥انخفاض نسبة االنتفاع بالطاقة الى .٣ والذي يعطي مؤشرا فيما لو تم تحسين تجهيز الطاقة الكهربائية للمعمل الرتفع نسبة % ٩٠,٥االنتاجي % . ٩٥االنتفاع بالطاقة المتاحة للمعمل الى :::: صياتالتو بعد استعراض االستنتاجات اعاله فان الباحث يضع بين يدي االدارة في المعامل التابعة لقطاع التشييد :التوصيات االتية البحث اوذوي العالقة ممن لهم صلة بموضوع هذ كفوءة في المعامل االنتاجية تأخذ بنظر االعتبار الطاقات المخططة والمتاحة وضع خطط انتاجية .١ غرض التوفيق بين مستويات االنتاج واالنتاجية في ظل المتاح من مستلزمات االنتاج الضرورية مع ل استخدام معايير االنتاجية لقياس االنتاجية للمعمل واالفراد واالستفادة منها في تقدير كلف االيدي العاملة .بشكل افضل شييد لغرض تشخيص االنحرافات وعالجها االهتمام بموضوع قياس وتقويم االداء لكافة معامل قطاع الت .٢ . ضع نظام تدريبي مرتبط بنتيجة كفاءة االداء للعمل بحيث يتم رفع مستوى مهارة العاملين وتطوير اداء و .٣ . متابعةاالنتاج واالعطال والتلكؤات في العمل ومعالجة ذلكبادخالهم دورات تدريبية ل ادارات المعامل بمستلزمات االنتاج وتنسيق التعاون مع الشركات والوزارت في مجال تبادل توفير المواد االولية الخاصة .٤ . المواد االولية الفائضة الغراض التوسع في االنتاج الى اقصى ما يمكن لسد الطلب المحلي متابعة التطورات التكنلوجية التي تحدث باستمرار في نظم المعلومات االدارية بهدف االستفادة من تلك .٥ .التطورات -:توصيات لدراسات مقترحة لقطاع التشييد على المعامل االنتاجية التابعة دراسة تطبيق متطلبات إدارة الجودة الشاملة .١ al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 13 واالسكان ومعامل شركات نظمة إدارة وتخطيط االنتاج لمعامل شركات وزارة االعمار الدراسة مقارنة .٢ وزارة الصناعة والمعادن قائمة المراجع 1richard b.chase “the service factory production” ,international jornal of service industry management ,1991. http : // taddeo . emeraldinsight . come تطبيقات االساليب الرياضية لتحديد العدد االمثل لإلداريين والمشرفين في المنشأت " عبد الملك، عادل 2 . 1993المجلد الثاني عشر ـ العدد الثاني ـ / مجلة الهندسة والتكنلوجيا ،" االنتاجية 3-b. adenso-diazi, pilargon zalez-torre, “acapacity management model in swrvice in dustries” , virginia garcia,2002. international jornal of service industry management . http : // taddeo . emeraldinsight . come 4stan brignall , joan ballantine , “performance measurement in service businesses revisited” international jornal of service industry management ,1997. http : // taddeo . emeraldinsight . come .1986القاهرة ، " ل الحديث من أدارة االفراد لالعمال المدخ" أسماعيل ، محمد عثمان -٥ نظم حسابات التكاليف في "أسماء قحطان ، بشرى نجم واْالورفلي، ماهر موسى والمشهداني .د، العبيدي ٦ وزارة االسكان ، " مقاوالت تنفيذ المشاريع نحو بناءمؤشرات لقياس كفاءة االداء قي قطاع المقاوالت االنشائية .1995،بغداد ، ندوة حسابات الكلف ، مير والتع 7-molnar, “facilities management handel book ,” van nostrand reihold company , new york , u.s.a ,1983. 8-lymon a.keith and gubellini cab “introduction to busines inter prise”4th edition. mc graw –hill, inc.singapare, 1984. 9 .١٩٩١، جامعة بغداد " أدارة الموارد البشرية "عادل حرشوف ، والصالح ، مؤيد سعيد ، السالم 10-chris d. storey , christopher “determinants of new produt performance” , international jornal of service industry management ,1996. http : // taddeo . emeraldinsight . come رسالة " تقويم أداء أدارة التشييد في مرحلة التنفيذ تطوير برنامج حاسوبي متفاعل ل" عماد ، الراغب ١١ . ١٩٩٩،الجامعة التكنولوجية –ماجستير al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 14 12-zhigang shen, wayne jensen, charles berryman, and yimin zhu “comparative study of activity-based construction labor productivity in the united states and china” american society of civil engineers 2011 univ. of nebraska–lincoln وبىبيانات المعمل المطلوبة للبرنامج الحاس )١(جدول رقم ١٤٨٣٢٠٠ الطاقة المخصصة لالنتاج ١٦٠٣٠٠٠ الطاقة المتاحة لالنتاج ٤٤٧٥١٤ الطاقة الفعلية لالنتاج ١١٠٠٠٠ السعر المخطط ٢٠٧٤ عدد العاملين ١ عدد الخطوط المشتغلة ٣ عدد الخطوط المخطط الشتغالها ١٣٠٣٧٨١٣٤٠ مصاريف الصيانة الفعلية ١٠ ية الناجحة عدد الفحوصات المختبر ١٠ عدد الفحوصات المختبرية الكلي ١٤٣١٠٠٩٦٦٨٧ كلفة االنجاز الفعلية ٠.٠٥ نسبة التلف في كمية االنتاج ٨١٩١٢٣٧٧٦٥ مجمل قيم االجور المدفوعة ٤٨٠٠٠٠ كمية االنتاج المخطط للفرن الواحد ٤١٤٠٠٠ كمية االنتاج الفعلي للفرن ١ ي الخط الواحد عدد االفران المشتغلة ف ١ عدد االفران المخطط الشتغالها al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 15 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 16 هيكلية البرنامج الحاسوبى )١(شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 17 واجهة البيانات الخاصة بمعمل سمنت الكوفة )٢(شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 18 واجهة نتائج البرنامج الخاصة بقياس كفاءة االداء )٣(شكل رقم al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 173 study the effect of working mass flow rate on the distillator performance in double – cycle distillation heat pump system mahdi hatf kadhum automotive technical department najaf technical college abstract: the performance of a distillator in a double – cycle distillation heat pump system, utilizing water as a working fluid in finned tube heat exchangers for evaporator and condenser, has been investigated. a mathematical model was set for the whole system and a simulating program was developed to simulate the double – cycle processes during the steady – state operation. this subroutine program to calculate the water and steam properties in the range of (65 – 115)oc and (0.25 – 1.6906)bar. the experimental results showed good agreement with the results obtained from the computer program. the concentration on the distillator performance during steady – state operation of the system is occurred, and it was found that the distillator performance (copdist.) increased when the working mass flow rate increased and also it was increased when the working fluid pressure increased and had a maximum value (83.3%) at working mass flow rate of 5.5 kg/hr, working fluid pressure of 0.8 bar and process fluid pressure of 1.01825 bar. دراسة تاثير معدل التدفق على اداء التقطير في المضخات مهدي هاتف كاظم الكلية التقنية نجف :الخالصة فــي مبــادالت حراريــة مــائع شــغل تــم دراســة أداء مقطــر فــي مضــخة حراريــة ثنائيــة الــدورة باســتخدام المــاء ك ثـم ، الرياضـي لكـال الـدورتين تـم وضـع الموديـل. ذات أنابيب مزعنفة لكل من المبخر و المكثـف كمنظومـة تقطيـر هـذا البرنـامج الفرعـي يعمـل . تم بناء برنامج حاسوبي لتمثيـل عمليـات المنظومـة خـالل عملهـا فـي الحالـة المسـتقرة النتـائج العمليـة أظهـرت توافقـا جيـدا . جـو) 1.6906 – 0.25(و ضـغط oم)115 – 65(ضمن مدى درجة حـرارة تـم التركيـز علـى أداء المقطـر خـالل عمـل المنظومـة فـي الحالـة . اسـوبيمع النتـائج المستحصـلة مـن البرنـامج الح al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 174 المســتقرة ووجــد إن معامــل أداء المقطــر يــزداد عنــدما يــزداد معــدل كتلــة جريــان مــائع الشــغل و كــذلك يــزداد عنــدما ، س�اعة/كغ�م)5.5(عنـد كتلـة جريـان مـائع الشـغل ) ٨٣.٣%(يزداد ضغط مائع الشغل و يصل إلى أعلى قيمـة لـه .جو) 1.01825(جو و ضغط المائع الثانوي ) 0.8(مائع الشغل ضغط nomenclature symbol description units ab bare tube outside surface area m 2 af fin surface area m 2 d pipe diameter m d depth m h enthalpy j/kg f convective boiling factor ــ h heat transfer coefficient w/m2.k li distance along the evaporator from its entrance m pr prandtle number ــ re reynolds number ــ s suppression factor w t thickness m wi width m w work w x quality ــ xi , j martinelli parameter where i , j refer to the nature of flow of the liquid and vapor phases greek symbols αpf ratio of the total heat transfer area to the total volume of the heat exchanger αv void fraction = av / atot β ratio of fin surface area to the total outside σ surface tension n/m 2 j,iφ ratio of the two – phase pressure gradient to the pressure gradient for single – phase liquid (or vapor) for that phase flowing alone in the pipe al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 175 subscript a acceleration av average b boiling con. condensate dist. distillator f fin ft flat tube he heat exchanger i element step l liquid – phase l low 1p single – phase 2p two – phase pf process fluid sat. saturation v vapor – phase w wall wf working fluid introduction: in recent years, population growth and its effect on industrial and agricultural requirements, has made the enhancement of fresh water resources a vital endeavor, as the demand for steady, economical supply of water is constantly increasing all around the world. many solutions to the water problem have been proposed, such as, control of water consumption, improved distribution, storage and desalination (al – atrooshi 1999) desalination desalination describes a range of processes which are used to reduce the amount of dissolved solids in water. as a means of producing potable water, desalination is usually an expensive option. it is often associated with electricity generation plants, from which both al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 176 electricity and waste heat are available (smith and shaw 2002 ) desalination by distillation distillation is the oldest and most commonly used method of desalination. in distillation process the saline water is heated to produce water vapor, which is then condensed to produce fresh water. the various distillation processes used to produce potable water, including multistage – flash (msf), multiple effect (med), vapor compression (vc), and waste – heat evaporators, all generally operate on the principle of reducing the vapor pressure of water within the unit to permit boiling to occur at lower temperatures, without use of additional heat. distillation is effective as a means for desalination because most of the chemical substances found in saline water are nonvolatile at boiling temperature, and hence remain in the unevaporated blow down liquids. the double (twin) cycle distillation heat pump system the double – cycle distillation system is a new method for producing potable water. one such system was presented at the committee of technology transfer conference (committee of technology 2001), by the name of zyclodest plant at 2001. zyclodest plant is a special mechanical vapor compression method. in it the working fluid exists in a separate loop for the heat recovery. thus, the product vapor, secondary fluid, is only contact with heat – exchangers and does not pass through the compressor and its rotating elements. the schematic diagram of this heat pump can be envisioned as shown in the fig. (1), and the double – cycle represented by the pressure – enthalpy diagram, as in fig. (2). according to fig.s (1) and (2) the coefficient of performance of distillator (copdist.) as follows: ( ) ( ) ( ) ( )7834 23 7834 76 21 l dist hhhh hh hhhh hh ww q cop −+− − = −+− − = + = ……..(1) the double – cycle distillation heat pump plant consists of two main cycles; the water compression – expansion cycle, which called also the compression – expansion vapor (cev) cycle, and the process cycle, see fig. (3). each of these cycles is described as follows: compression – expansion vapor cycle the compression – expansion vapor cycle consists of compressor, expansion device, and two heat – exchangers with interconnecting piping. one of the heat – exchangers submerged in a pool boiling liquid and represents a condenser coil, which is mounted at an angle of inclination of about 15 degree with respect to the horizontal so as to allow for condensate drainage. the other heat – exchanger is exposed to a collective vapor and represent an evaporator coil. the evaporator and the condenser are mounted at the same angle to simplify the construction. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 177 process cycle this cycle consists of three main parts with interconnecting piping, namely: evaporation chamber, intermediate (im) zone and condensation chamber. a brief description of this cycle is as follows: in the evaporation chamber (boiler), the evaporator coil submerged in a pool of water and the heat will transfer through the evaporator walls to the water in the pool. due to this heat transferred, water will boil and the amount of evaporative mass depends on the amount of heat transfer. the vapor will rise due to the difference in density to pass through the intermediate zone through corrugated channel. this part is used to avoid mist flow, and then the vapor enters the condensation chamber as a saturated vapor. in the condensation chamber, the condenser coil is exposed to the saturated vapor. due to the heat transferred to the working fluid inside the condenser through the walls of the condenser, the vapor will condensate on the outside walls of the condenser. the condensate will exit from the condensation chamber and return to the evaporation chamber by the distillate water pump, by gravity, or the pressure difference. the heat exchangers used for evaporator and condenser of the double – loop distillation heat pump system are finned tube heat exchangers, as shown in fig. (4). theory; a mathematical model will be set for the two loops and a computational program will be developed to simulate the two loops during steady – state operation for knowing the effect of the working mass flow rate on the distillatior performance. the analysis for the working and process fluid, the evaporator and the compressor during the steady – state operation of the system may describe as follows: physical properties working and process fluid the working and process fluids in both the cev and process loops respectively are that of pure water. the properties of pure water as required for simulation can be divided into: a. thermodynamic properties: which include (υ, i, s, cp and cv), obtained from (uk steam tables in si units 1970) . b. transport properties: which include (ρ, k, µ and σ), obtained from ( al – atrooshi 1999 ) all the above thermodynamic and transport properties are calculated for subcooled and saturated liquid and saturated and superheated vapor using standard table correlations, in the temperature range of (65 – 115) oc. for saline water, the thermodynamic and transport properties are direct functions of al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 178 temperature and degree of salinity and in some cases they are established based on comparison with the same properties for pure water. the essential empirical equations for these properties as a function of temperature and degree of salinity were obtained from (al – atrooshi 1999 ) walls and insulation the properties of the system materials and insulation are assumed constant. also the thermal conductivity for insulation (glass wool), pipes (copper and wrought iron), fins and tubes of the heat exchangers (aluminum), and system body (galvanized plats) are obtained from (ashrae handbook 1997) and (holman 2008 ). heat transfer analysis modeling of evaporator referring to fig. (5), the heat transfer rate from the process fluid (vapor) to the working fluid (two – phase flow) in an element (i) in the evaporator is: qi = convective heat transfer = conduction heat transfer = convective heat transfer from process fluid to the through the wall of from the wall of element the wall of element (i) element (i) (i) to the working fluid ……..(2) wf wfinw, w inw,ow, pf ow,pf r tt r tt r tt − = − = − = ……..(3) wfwpf wfpf rrr tt ++ − = ……..(4) and, ( ) pfwwf o rrr 1 ua ++ = ……..(5) outside convective thermal resistance vapor (process fluid) – side convective thermal resistance is given as (holman 2008 ). tot.ooi, pf ηha 1 r = ……..(6) outside surface area of the heat exchanger is calculated for each element length as follows: al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 179 ( )heheipfoi, dwilαa = ……..(7) outside heat transfer coefficient the outside condensation heat transfer coefficient is calculated by the following correlation ( al – atrooshi 1999 ) for rel < 1800 ( ) ( ) 4 1 wvhl fg 3 lvll o ttdµ hkgρρρ 0.725h         − − = ……..(8) for rel > 1800 ( ) ( ) 4 1 wvhl fg 3 lvll o ttdµ hkgρρρ b0.725h         − − = ……..(9) where, ( ) ( )2nr0.00157035nr0.03538081.23795b −+= ……..(10) nr : is the number of tube rows of the heat exchanger. the condensate in an actual condensation process is cooled farther to some average temperature between saturation temperature (tsat.) and wall temperature (tw), releasing more heat in the process. therefore, the actual heat transfer will be large, and the (hfg) replacing by the modified latent heat of condensation (hfg *), which defined as follows( yunus. and michael 2007) for saturated vapor at the evaporator outside, ( )wsat.lfgfg ttcp0.68hh −+=∗ ……..(11) for superheated vapor at the evaporator outside, ( ) ( ) sat.vvwsat.lfgfg ttcpttcp0.68hh −+−+= ∗ ……..(12) fin analysis: the total fin efficiency (ηtot.) is calculation from the following equation (sarsam 1995) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 180 surfacefinandtubefromtransferheatmaximum surfacefinandtubefromtransferheattotal ηtot. = ……..(13) ( ) ( ) ( ) ( )wo,pffbpf wo,pfffpfwo,pfbpf ttaah ttηahttah −+ −+− = ……..(14) ( )fpf fb ffb η1β1 aa ηaa −−= + += ……..(15) for continuous fins, fin efficiency (ηf) is calculated using the following equation : ( ) f f f hm hmtanh η = ……..(16) where, 2 1 ff o tk h2 m       = ……..(17) the fin efficiency (ηf) is multiplied by (2), because there are two fins protrude from the same point at the outer – surface of the flat tube of the evaporator, see figs. (4) and (5). conduction thermal resistance the thermal resistance due to conduction is given as (as holman 2008 ) shown in fig(4): ftav ft w ka t r = ……..(18) where,       −= in o ino av a aln aa a ……..(19) ( ) iftfto lwil2a += ……..(20) ( ) ( )[ ] iftftftftin ltwitl2a −+−= ……..(21) inside convective thermal resistance the working fluid – side convective thermal resistance is given as: inin wf ah 1 r = ……..(22) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 181 since the working fluid inlet to the evaporator as two – phase flow, therefore, the two – phase heat transfer coefficient is calculated according to the correlation proposed by (chen 1966) as follows: h2p = hcon. + hb ……..(23) ( ) f d k pr µ dx1g 0.023h ll 0.8 l con.       −= ……..(24) ( ) ( ) spptt ρhµσ ρcpk 0.00122h 0.75sat.w 0.24 sat.w0.24 v 0.24 fg 0.29 l 0.5 0.49 l 0.45 l 0.79 l b −−=         ……...(25) where, 0.1 x 1 when0.213 x 1 2.35f 0.1 x 1 when1f tt, 0.736 tt, tt, >+= <=         ……..(26) ( ) ( ) 70refor1s 70re32.5forre0.421s 32.5reforre0.121s 2p 2p 10.78 2p 2p 11.14 2p >= <<+= <+= − − ……..(27) 0.1 l v 0.5 v l 0.9 tt, µ µ ρ ρ x1 x x 1                   − = ……..(28) ( ) 41.25 l 2p 10f µ dx1g re −⋅−= ……..(29) when the quality (x) of the two – phase working fluid reaches to unit, then single – phase (vapor) is occurred. therefore may using the correlation proposed by (sieder, and tate 1936 ) to calculate the heat transfer coefficient (hin), for laminar or turbulent fully developed hydrodynamic flow. for laminar flow (re < 2400), 0.14 w 3 1 i h h 1p µ µ l d prre d k 1.24h             = ……..(30) for turbulent flow (re > 2400), 0.14 w 4.08.0 h 1p µ µ prre d k 027.0h       = ……..(31) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 182 modeling of compressor since, the working fluid always enters the compression chamber as vapor. thus, ideal gas laws may be applied on it for relations of pressure – temperature and pressure – volume, (ashrae 2000) the shaft work of the compressor with known mass flow rate may calculated as follows:                   − − = − 1 p p. vp 1γ γ w γ 1γ 1 2 11 ……..(32) when the compression of the gas occurred with existence of losses (poletrophic compression process), thus, the specific heat ratio (γ) equal to the power (n). hydrodynamic analysis working fluid – side for single – phase flow, the frictional pressure drop is calculated from the following relation (franzini. and finnemore 1997) ρ2 g d l 4∆p 2 h i frc,1p f= ……..(33) where, for single – phase laminar flow re 16=f ……..(34) and, for single – phase turbulent flow 0.25re 0.079=f ……..(35) for two – phase flow, the correlations of lockhart and martinelli are used to relate the two – phase frictional pressure drop to the single – phase liquid frictional pressure drop, evaluated using equations (33) to (35), assuming that the liquid – phase alone is occupied the tubes. in addition, their empirical correlation for the void fraction (αv) in the two – phase flow region is used (sarsam 1995) frc,1p 2 ji,frc,2p ∆pφ∆p = ……..(36) and, ( ) 0.3780.8ji,v x1α −+= ……..(37) subscripts i and j represents the nature of the flow for the liquid and vapor phases al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 183 respectively. four such conditions may obtain from (sarsam 1995) the appropriate relation for xi,j is used to calculate the void fraction and φi,j , which in turn is used to determine the two – phase pressure drop. the hydrostatic pressure drop for the working fluid is calculated from: ( )θsinlgρ∆p imh = ……..(38) where, ρm : is the mean density of the mixture given by the following equation: ( ) lvvvm ρα1ραρ −+= ……..(39) and, θ : is the angle of inclination of the heat exchanger. the acceleration pressure drop is calculated from the following correlation (sarsam 1995) ( )         −+ − −= 1 ρ ρ α x α1 x1 ρ g ∆p v l v 2 v 2 l 2 a ……..(40) further more, the pressure losses occurring at the entrance and exit of the heat exchanger are evaluated using the relations proposed by,( kays and london1964) ( )2 2 ent. σ1 ρ2 g ∆p −= ……..(41) ( )1σ ρ2 g ∆p 2 2 exit −= ……..(42) where, σ : is the ratio of free flow area to frontal area. scope of experiment this work performed for investigation of the distillation performance process in the heat pump system with varying the distillation conditions. experimental setup the double – cycle distillation heat pump system for desalination, utilizing water as the working and process fluid, is designed and constructed in accordance with the schematic diagram in fig. (6). the two – loops of the heat pump are a sealed system charged with a known mass of working and process fluid and work under different pressures. the two – loops are insulated in al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 184 order to minimize heat flow to ambient. a pictorial view of the test rig is shown in fig. (7). experimental program was initiated to studying the influence of mass flow rate of the cev loop on the evaporator (distillator) performance. the evacuating and charging the system are attained using two different points for cev loop and four different points for thermosyphon loop, and a fifth point at the bottom of the liquid line is used to specify the level of the feed water in the evaporation chamber. the heat exchangers used for the evaporator and condenser has an outside surface area of about (0.325 m2). the liquid, liquid – vapor and the vapor lines are constructed from 1/2 and 5/8 inch soft copper tubes. the expansion device is a 1/2 inch ball valve and the compressor is a rolling piston (fixed van) type. the evaporation and condensation chambers are constructed with a shape coincide with the size and configuration of the condenser and the evaporator coils respectively. the intermediate zone is constructed from three inclined channels in the space between the evaporation and the condensation chambers. a (600) watt water heater is installed in the evaporation chamber using 5/8 inch carbon steel nut which welded to (20) mm diameter hole at the outer surface of the chamber below the charging point. this heater is used as start – heating to reach the raw water to the boiling degree at the beginning of the operation. the liquid (distillated water) and vapor lines are constructed from 1/2 and 3/4 inch galvanized (wrought iron) pipes respectively. 3/4 inch gate valve is used as expansion device. distillated water is used as the working fluid in cev loop since it's a cheap, good, and available working fluid. its also used as process fluid in thermosyphon loop to facility the distillator performance investigation. instrumentation and calibration temperature measurement thermally sensitive resistors (thermistors) are used to measure the working and process fluid temperatures in all parts of the test rig. the thermistors are connected to a selector switche. the selector switche are connected to a digital multimeter (hp 3435a) with a sensitivity of 0.1 ω. calibration of thermistor is carried out with temperature range of (70 – 110) oc. pressure measurement a pressure gages, bourdon type, are calibrated and used to measure the pressure of working fluid at the inlet and outlet of the evaporator and compressor. water flow rate measurement an orifice plate is calibrated and used to measure the volumetric flow rate of water inside the compression – expansion vapor loop. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 185 leak tests before starting up the test runs for the system, the leak tests are carried out for the two – loops of the system. system insulation in order to minimize the heat transfer with the surrounding, a glass wool sheets, with different thickness (1, 1.5, 2) cm, insulation covered by an aluminum foil are used to cover the all parts of the two – loops of the system, as shown in fig. (7). results and discussion: the performance of the cev loop working with different mass flow rate is defined as a coefficient of performance for distillator (copdist.), as follows: shaft comp. e dist. w q cop = ……..(43) where, ( )inoute hh . mq −= ……..(44)                   − − = − 1 p p. vp 1n n w n 1n 1 2 11shaft comp. ……..(45) the effect of working mass flow rate distillator performance for different process fluid pressure is shown in fig.(8) to fig.(10) at different working fluid pressure. the experimental results are projected on the computed curves. from the figures it is shown that the experimental results are lower than the computed values. this difference may attribute to the experimental errors involved in the measurement of the copdist. in addition to the experimental errors, the systematic errors such as the presence of non – condensable gases in the loop, this gas will collect on the condensing side while condensation takes place. for all figures, it is shown that at any process fluid pressure, increasing the working mass flow rate causes an increase in the distillator performance (i.e. copdist), this can be explained by the fact that when the working mass flow rate is increased, the liquid – vapor column in the evaporator will be increased. so that, the effective evaporator heat transfer surface area is increased as well. therefore, the heat absorbed by the evaporator is increased and causes the loop performance to increase. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 186 conclusions: 1. the computed results were in good agreement with the experimental data obtained from the test rig, for the distillator performance. 2. the water is used as working fluid and can provide reasonably accurate results during the experiments. in addition it is cheap and available. 3. for all working fluid pressure, i.e. 0.7, 0.75 and 0.8 bar, any increase in the working mass flow rate will clearly increase the cev loop performance due to increase the liquid – vapor column in the evaporator. 4. the maximum cev loop performance was seen to occur at a working mass flow rate of 5.5 kg/hr at working fluid pressure of 0.8 bar. acknowlegement: all experiments for this work are performed by the test rig which built by h. gh. al – hussaini references: 1. al – atrooshi, s.a.w. "investigation of multi – stage flash evaporation desalination", a ph.d. thesis, university of baghdad, 1999. 2. smith, m. and shaw, r. "desalination by reverse osmosis and distillation", wedc loughborough university, 2002. 3. committee of technology "zyclodest distillation plant" germany, 2001. 4. uk steam tables in si units, london: edward arnold (publishers) ltd., 1970. 5. ashrae handbook "fundamentals volume", new york, 1997. 6. holman, j.p. "heat transfer", mcgraw – hill book company, 2008. 7. yunus, a.c. and michael, a.b. "thermodynamic an engineering approach", mcgrow – hill book company, 2007. 8. sarsam, w.s. "the performance of thermosyphon system as a heat regenerator", m.sc. thesis, university of baghdad, 1995. 9. chen, j.c. "correlation for boiling heat transfer to saturated fluids in convective flow", inst. eng. chem. process design and development, vol. 5, no. 3, pp. 322 – 329, 1966. 10. sieder, e.n. and tate, j.e. "heat transfer and pressure drop of liquids in tubes", ind. and eng. chem., vol. 28, no. 12, pp. 1429 – 1434, 1936. 11. ashrae handbook "systems and equipment volume", new york, 2000. 12. franzini, j.b. and finnemore, e.j. "fluid mechanics with engineering applications", mcgraw – hill book company, ninth edition, 1997. 13. al – wakil, b.k. "parametric study of the two – phase thermosyphone system", m.sc. thesis, university of baghdad, 1998. 14. kays, w.m. and london, a.l. "compact heat exchanger", mcgraw – hill book company, 1964. \(microsoft word 9 \\343\\307\\345\\321 \\332\\310\\317 \\307\\341\\307\\343\\355\\321\) al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method maher abdul ameer lecturer technical college of mussaib abstract this research is devote to a description of the methods available for the analysis of unsteady flows in pumping stations and their associated hydraulic systems. there are two basic approaches to the solution of unsteady internal flows: solution in the time domain and in the frequency domain. the traditional time domain methods for hydraulic systems are the most important that many unsteady hydraulic system problems can and should be treated by the time domain or “water-hammer” methods. another approach is frequency domain method, it is sufficient to recognize that one practical advantage of this method is the capability of incorporation of experimentally obtained dynamic information and the greater simplicity of the experiments required to obtain the necessary dynamic data, the disadvantage of frequency domain is that the method are limited to small linear perturbations in the flow rate. two types of networks are tested in this research, example (1) represents very simple network without any apparatus, and example (2) network containing some complexity and containing intakes, valves, and other apparatus. the results in example (1) identical for both methods, but in example (2) the results showing clear differences for the two approaches. المقارنة العددية لجريان انتقالي في شبكات االنابيب باستخدام طريقتي المدى الزمني والمدى الترددي موجزال نظري عن الطرق المتاحة لتحليل الجريان االنتقالي الذي يحصل في كرس ما موجود في هذا البحث للتعبير بشكل هناك طريقتين اساسيتين لحل مسائل الجريان الداخلي الغير . محطات الضخ والنظم الهيدروليكية الملحقة بها الطرق طريقة المدى الزمني التقليدية تعتبر من اهم . الحل بطريقة المدى الزمني وطريقة المدى الترددي: مستقر . الشائعة لحل مشاكل الجريان االنتقالي الذي يحصل في المنظومات الهيدروليكية او ما يعرف بالمطرقة المائية هناك طريقة اخرى للتعبير عن حالة الجريان االنتقالي وهي طريقة المدى الترددي حيث تتميز هذه الطريقة بكفاءتها لكن لهذه الطريقة قصور ، عليها من تجربة مختبرية وتحليلها نظرياعلى ربط البيانات المختبرية التي يمكن الحصول كونها كفؤة فقط في وصف الجريان االنتقالي الذي يحوي دوامات واضطرابات صغيرة وعادة ما تحصل في الشبكات االول المثال، تم اختبار نوعين من الشبكات في هذا البحث على شكل مثالين. الصغيرة التي ال تحوي ملحقات كثيرة maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 210 وجدت النتائج . يحوي شبكة بسيطة خالية من الملحقات والمثال الثاني يتضمن شبكة اكثر تعقيد وتحوي ملحقات .بينما في المثال الثاني تم مالحظة عدم تطابق في النتائج لكال الطريقتين، للمثال االول متطابقة لكال الطريقتين nomenclature a : cross-sectional area. a :radius. e: specific internal energy. e[f]l: transmission matrix. [f]: distributed function. δ :wall thickness of the pipe. ρ :fluid density. c : sonic speed. c∞: sonic speed in the fluid. e: young’s modulus. n: order of the system. p : pressure. k: bulk modulus. q-n : vector of fluctuating quantity. s: coordinate measuredalong the duct. t : time. [tij]: transfer matrix elements. [t] : transfer matrix based on p͠t, m ͠. [t*] :transfermatrix based on p ͠ , m͠. u(s, t): volumetric velocity. gs :acceleration due to gravity. λ : characteristic factor. f : friction factor. h∗ :piezometric head. q : volume flow rate. ω: frequency. m: mass flow rate. pt: total pressure. re: reynolds number. z: vertical elevation. introduction hydraulic transients are the time-varying phenomena that follow when the equilibrium of steady flow in a system is disturbed by a change of flow that occurs over a relatively short time period. the verity of transient pressures must be determined so that the water mains can be properly designed to withstand these additional loads. in fact, pipes are often characterized by their “pressure ratings” that define their mechanical strength and have a significant influence on their cost (boulos, 2004).transient regimes in water distribution systems are inevitable and will normally be most severe at pump stations and control valves, high elevation areas, locations with low static pressures, and remote locations that are distanced from overhead storage (friedman 2003). all systems will, at some time, be started up, switched off, undergo unexpected flow changes, etc., and will likely experience the effects of human errors, equipment break downs, or other risky disturbances. although transient conditions can result in many situations, the engineer is most concerned with those that might endanger the safety of a plant and its personnel that have the potential to cause equipment or device damage that results in numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 211 operational difficulties or pose a risk to the public health. transient events have significant water quality implications. these events can generate high intensities of fluid shear and may cause suspension of settled particles as well as bio film detachment. so-called red water events have often been associated with transient disturbances. moreover, a low-pressure transient event, say arising from a power failure or pipe break, has the potential to cause the intrusion of contaminated groundwater into a pipe at a leaky joint or break. depending on the size of the leaks, the volume of intrusion can range from a few gallons to hundreds of gallons (funk 1999, karim, 2003 and le chevallier 2003). negative pressures induce back siphon age of no potable water from domestic, industrial, and institutional piping into the distribution system. dissolved air gas can also be released steel and iron sections with subsequent rust formation and pipe damage. even some common transient protection strategies, such as relief valves or air/vacuum valves, if not properly designed and maintained, may permit pathogens or other contaminants to find a “back door” route into the potable water distribution system. engineers must carefully consider all potential dangers for their pipe designs and estimate and eliminate the weak spots. they should then embark upon a detailed transient analysis to make informed decisions on how to best strengthen their systems and ensure safe, reliable operations (karney and mcinnis 1990). theoretical analysis 1-time domain method the application of time domain methods to one-dimensional fluid flow normally consists of the following three components. first, one establishes conditions for the conservation of mass and momentum in the fluid. these may be differential equations or they may be jump conditions (as in the analysis of a shock). second, one must establish appropriate thermodynamic constraints governing the changes of state of the fluid. in almost all practical cases of single-phase flow, it is appropriate to assume that these changes are adiabatic. however, in multiphase flows the constraint scan be much more complicated. third, one must determine the response of the containing structure to the pressure changes in the fluid. the analysis is made a great deal simpler in those circumstances in which it is accurate to assume that both the fluid and the structure behave bar tropically. by definition, this implies that the change of state of the fluid is such that some thermodynamic quantity (such as the entropy) remains constant, and therefore the fluid density, ρ(p), is a simple algebraic function of just one thermodynamic variable, for example the pressure. in the case of the structure, the assumption is that it deforms quasi statically, so that, for example, the cross-sectional area of a pipe, a (p), is a simple, algebraic function of the fluid pressure, p. note that this neglects any inertial or damping effects in the structure. the importance of the assumption of a bar tropic fluid and structure lies in the fact that it allows the calculation of a single, unambiguous speed of sound for waves raveling through the piping system. the sonic speed in the fluid alone is given by c∞ where [3] (1) in a liquid, this is usually calculated from the bulk modulus, κ = ρ/(dρ/dp),since (2) however the sonic speed, c, for one-dimensional waves in a fluid-filled duct isinfluenced by the compressibility of both the liquid and the structure [3] maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 212 (3) or, alternatively, (4) the left-hand side is the acoustic impedance of the system, and the equationreveals that this is the sum of the acoustic impedance of the fluid alone, 1/ρc2∞,plus an “acoustic impedance” of the structure given by (da/dp)/a. for example,for a thin-walled pipe made of an elastic material of young’s modulus, e, theacoustic impedance of the structure is 2a/eδ, where a and δ are the radius andthe wall thickness of the pipe (δ a). the resulting form of equation (4), [3] (5) in order to solve unsteady flows in ducts, an expression for the sonic speed iscombined with the differential form of the equation for conservation of mass(the continuity equation), (6) where u(s, t) is the cross-sectionally averaged or volumetric velocity, s is a coordinatemeasured along the duct, and t is time. the appropriate differentialform of the momentum equation is [3] (7) where gs is the component of the acceleration due to gravity in the s direction, f is the friction factor, and a is the radius of the duct. now the barotropic assumption (3) allows the terms in equation (6) to bewritten as [3] (8) so the continuity equation becomes (9) equations (7) and (9) are two simultaneous, first order, differential equationsfor the two unknown functions, p(s, t) and u(s, t). they can be solved giventhe barotropic relation for the fluid, ρ(p), the numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 213 friction factor, f, the normalcross-sectional area of the pipe, a0(s), and boundary conditions which will bediscussed later. normally the last term in equation (9) can be approximated byρu(da0/ds)/a0. note that c may be a function of s. in the time domain methodology, equations(7) and (9) are normally solvedusing the method of characteristics. this involvesfinding moving coordinate systems in which the equations may be writtenas ordinary rather than partial differential equations. consider the relation thatresults when we multiply equation (9) by λ and add it to equation (7)[3] (10) if the coefficients of ∂u/∂s and ∂p/∂s inside the square brackets were identical, in otherwords if λ= ±c , then the expressions in the square brackets could be writtenas (11) and these are the derivatives du/dt and dp/dt on ds/dt = u ± c. these lines ds/dt = u ± c are the characteristics, and on them we may write: 1. in a frame of reference moving with velocity u + c or on ds/dt = u + c: (12) 2. in a frame of reference moving with velocity u − c or on ds/dt = u − c: (13) a simpler set of equations result if the piezometric head, h∗, defined as (14) is used instead of the pressure, p, in equations (12) and (13). in almost allhydraulic problems of practical interest p/ρlc2 1 and, therefore, the termρ-1dp/dt in equations (12) and (13) may be approximated by d(p/ρ)/dt. it follows that on the two characteristics [3] maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 214 (15) and equations (12) and (13) become 1. on ds/dt = u + c (16) 3. on ds/dt = u – c (17) these are the forms of the equations conventionally used in unsteady hydraulic water-hammer problems (streeter and wylie, 1967). they are typically solved by relating the values at a time t + δt {for example point c of figure 1} to known values at the points a and b at time t. the lines ac and bc are characteristics, so the following finite difference forms of equations (16) and (17) apply [3] (18) and, (19) if ca = cb = c, and the pipe is uniform, so that da0/ds = 0 and fa = fb = f, then these reduce to the following expressions for uc and h∗c uc= + (h * a – h * b ) + {ua(gs)a– ub(gs) b}-b {ua + ub│ub│} (20) (21) 1-1-method of characteristics the typical numerical solution by the method of characteristics is depicted graphically in figure 2. the time interval, δt, and the spatial increment, δs, are specified. then, given all values of the two dependent variables (say u and h∗) at one instant in time, one proceeds as follows to find all the value numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 215 sat points such as c at a time δt later. the intersection points, a and b, of the characteristics through c are first determined. then interpolation between the known values at points such as r, s and t are used to determine the values of the dependent variables at a and b. the values at c follow from equations such as (20) and (21) or some alternative version. repeating this for all points at time t + δt allows one to march forward in time. there is, however, a maximum time interval, δt, that will lead to a stable numerical solution. typically this requires that δt be less than δx/c. in other words, it requires that the points a and b of figure 2 lie inside of the interval rst. the reason for this condition can be demonstrated in the following way. assume for the sake of simplicity that the slopes of the characteristics are ±c; then the distances as = sb = cδt. using linear interpolation to find ua and ub from ur, us and ut leads to [2] (22) but this is also a principal term in the expression (20) for uc. consequently, an error in us of, say, δu would lead to an error in uc (at the same location but δt later) of δucδt/δs. thus the error would be magnified with each time step unless cδt/δs < 1 and, therefore, the numerical integration is only stable if δt< δx/c. in many hydraulic system analyses this places a quite severe restriction on the time interval δt, and often necessitates a large number of time steps. a procedure like the above will also require boundary conditions to be specified at any mesh point which lies either, at the end of a pipe or, at a junction of the pipe with a pipe of different size (or a pump or any other component). if the points s and c in figure 2 were end points, then only one characteristic would lie within the pipe and only one relation, (18) or (19), can be used. therefore, the boundary condition must provide a second relation involving uc or h*c (or both). an example is an open-ended pipe for which the pressure and, therefore, h* is known. alternatively, at a junction between two sizes of pipe, the two required relations will come from one characteristic in each of the two pipes, plus a continuity equation at the junction ensuring that the values ofua0 in both pipes are the same at the junction. for this reason it is sometimes convenient to rewrite equations (16) and (17) in terms of the volume flow rate q = ua0 instead of u so that [2] 1. on ds/dt = u + c (23) 2. on ds/dt = u − c (24) in many time domain analyses, turbomachines are treated by assuming thatthe temporal rates of change are sufficiently slow that the turbomachine respondsquasistatically, moving from one steady state operating point to another.consequently, if points a and b lie at inlet to and discharge from theturbomachine then the equations relating the values at a and b would be (25) (26) maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 216 where h(q) is the head rise across the machine at the flow rate, q. data presented later will show that the qua sistatic assumption is only valid for rates of change less than about one-tenth the frequency of shaft rotation. for frequencies greater than this, the pump dynamics become important. 2 frequency domain methods when the quai-static assumption for a device like a pump or turbine becomes questionable, or when the complexity of the fluid or the geometry makes the construction of a set of differential equations impractical or uncertain, then it is clear that experimental information on the dynamic behavior of the device is necessary. in practice, such experimental information is most readily obtained by subjecting the device to fluctuations in the flow rate or head for a range of frequencies, and measuring the fluctuating quantities at inlet and discharge. all the dependent variables such as the mean velocity, u, mass flow rate, m, pressure, p, or total pressure, pt , are expressed as the sum of a mean component (denoted by an overbear) and a complex fluctuating component (denoted by a tilde) at a frequency, ω, which incorporates the amplitude and phase of the fluctuation [2] (27) (28) (29) wherej is (−1)1/2and re denotes the real part. since the perturbations are assumed linear (|˜u| ¯ u, | ˜m| ¯ m, etc.), they can be readily superimposed, so a summation over many frequencies is implied in the above expressions. in general, the perturbation quantities will be functions of the mean flow characteristics as well as position, s, and frequency, ω. we should note that there do exist a number of codes designed to examine the frequency response of hydraulic systems using frequency domain methods. 2-1 order of the system the first step in any unsteady flow analysis is to subdivide the system into components; the points separating two (or more) components will be referred to as system nodes. typically, there would be nodes at the inlet and discharge flanges of a pump. having done this, it is necessary to determine the order of the system, n, and this can be accomplished in one of several equivalent ways. the order of the system is the minimum number of independent fluctuating quantities which must be specified at a system node in order to provide a complete description of the unsteady flow at that location. it is also equal to the minimum number of independent, simultaneous first order differential equations needed to describe the fluid motion in. in this research, we assume the system includes water-hammer analysis in which the local area depends on the area and the pressure elsewhere, and then the system is of order 3. 2-2 transfer matrices the transfer matrix for any component or device is the matrix which relates the fluctuating quantities at the discharge node to the fluctuating quantities at the inlet node. the earliest exploration of such a concept in electrical networks appears to be due to (strecker and feldtkeller, 1929). if the quantities at inlet and discharge are denoted by subscripts i = 1 and i = 2, respectively, and, if {qi ~n }, n = 1, 2 → n denotes the vector of independent fluctuating quantities at inlet and discharge for a system of order n, then the transfer matrix, [t], is defined as [10] numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 217 (30) (31) the most convenient independent fluctuating quantities for a hydraulic system of order two are usually 1. either the pressure, ˜p, or the instantaneous total pressure, p~t. note that these are related by (32) where ρis the mean density, ρ ~ is the fluctuating density which is bar tropically connected to ˜p, and z is the vertical elevation of the system node. neglecting the ˜ρ terms as is acceptable for incompressible flows (33) 2. or the velocity, u˜, the volume flow rate, {a¯ u˜ + u¯ a}̃, or the mass flow rate, {m˜ = ρ¯ a¯ u˜ + ρ¯ u¯ a˜ + u¯ aρ̄˜}. incompressible flow at a system node in a rigid pipe implies (34) the most convenient choices are {p~, m~} or {p~t, m~ }, and, for these two vectors, we will respectively use transfer matrices denoted by [t*] and [t], defined as (35) 2-3 distributed systems in the case of a distributed system such as a pipe, it is also appropriate to define a matrix [f] so that [10] (36) note that, apart from the frictional term, the equations (12) and (13) for flow in a pipe will lead to perturbation equations of this form. furthermore, in many cases the frictional term is small, and can be approximated by a linear term in the perturbation equations; under such circumstances the frictional term will also fit into the form given by equation (37).when the matrix [f] is independent of location, s, the distributed system is called a “uniform system”. for example, in equations (12) and (13), this would require ρ, c, a, f and a0 to be approximated as constants (in addition to the linearization of the frictional term). maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 218 under such circumstances, equation (37) can be integrated over a finite length, l, and the transfer matrix[t] of the form (35) becomes (37) where e[f]l is known as the “transmission matrix.” for a system of order two, the explicit relation between [t] and [f] is [10] (38) where λ1, λ2 are the solutions of the equation (39) 2-4 combinations of transfer matrices when components are connected in series, the transfer matrix for the combination is clearly obtained by multiplying the transfer matrices of the individual components in the reverse order in which the flow passes through them. thus, for example, the combination of a pump with a transfer matrix, [ta], followed by a discharge line with a transfer matrix, [tb], would have a system transfer matrix, [ts], given by [10] (40) the parallel combination of two components is more complicated and does not produce such a simple result. issues arise concerning the relations between the pressures of the inlet streams and the relations between the pressures of the discharge streams. often it is appropriate to assume that the branching which creates the two inlet streams results in identical fluctuating total pressures at inlet to the two components,[p1 ~t]. if, in addition, mixing losses at the downstream junction are neglected, so that the fluctuating total pressure, [p2 ~t] , can be equated with the fluctuating total pressure at discharge from the two components, then the transfer function, [ts], for the combination of two components (order two transfer functions denoted by [ta] and [tb]) become (41) on the other hand, the circumstances at the junction of the two discharge streams may be such that the fluctuating static pressures (rather than the fluctuating total pressures) are equal. then, if the inlet static numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 219 pressures are also equal, the combined transfer matrix, [ts*], is related to those of the two components [ta*] and [tb*] by the same relations as given in equations (42).other combinations of choices are possible. using the above combination rules, as well as the relations (36) between the [t] and [t*] matrices, the transfer functions for very complicated hydraulic networks can be systematically synthesized. practical applications case (1) the first example network was studied earlier by streeter and wylie (1967) and is shown in figure 3. the network comprises nine pipes, five junctions, one reservoir, three closed loops, and one valve located at the downstream end of the system. the valve is shut to create the transient. table 1 summarizes the pertinent pipe system characteristics. the reservoir level is clearly shown in the figure 3, the analysis resulting very identical plots as shown in figures 5 and 6 [11] case (2) using a slightly larger more complex system, the methods were applied to the network shown in figure 4. this represents an actual water system and consists of (7) pipes, (4) junctions, two supply tank, and one surge tank. reservoir valves (orifices) usually permit flow in both directions. otherwise, a valve discharging to the atmosphere is equivalent to an infinite area reservoir. all valves (orifices) are considered fully open, expect the control valve at node (7) and pressure relief valve. table 2 summarizes the pertinent pipe system characteristics. figure 8 compares the transient results obtained using the time domain method and the frequency domain method solutionschemes from node (1) to node (7), the demand is changed by reducing the inflow to zero over a period of 6 s. the analysis resulting in a required time step of 0.0139 s. as can be seen from figures 7 and 8, the methods yielded not identical results [3] conclusion transient (water hammer) analysis is essential to good design and operation of piping systems. this important analysis can be done using the mathematically time domain method based on the method of characteristics or the frequency domain method for order three. the two methods are both capable of accurately solving for transient pressures and flows in simple water distribution networks including the effects of pipe friction. the method of characteristics requires calculations at interior points to handle the wave propagation and the effects of pipe friction. the frequency domain method handles these effects by using the transfer matrix, the transfer matrix of order three used in this research. the results showed that for small simple networks without any apparatus the two methods given identical readings, but for large networks with some apparatus the two methods given different results. references • boulos, p. f., lansey, k. e., and karney, b. w. comprehensive water distribution systems analysis handbook for engineers and planners, mwh soft, inc., pasadena, calif (2004). • bruce e. larock, roland w. jeppson, gary z. watters, hydraulic of pipeline systems, (2000). • christopher e. brennen, california institute of technology, pasadena, california, (1994). • friedman, m. c. “verification and control of low pressure transients in distribution systems,” proc., 18th annual asdwa conf., association of state drinking water administrators, boston (2003). maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 220 • funk, j. e. “pathogen intrusion into water distribution systems due to transients,” proc., asme/jsme joint fluids engineering conf., asme/jsme, san francisco(1999). • karim, m. r., abbaszadegan, m., and lechevallier, m. w. “potential for pathogen intrusion during pressure transients,” j. am. water works assoc., (95-5), (134–146), (2003). • karney, b. w., andmcinnis, d. “transientanalysisofwaterdistributionsystems,” j. am. water works assoc., (82-7), (62–70), (1990). • lechevallier, m. w. . “the potential for health risks from intrusion of contaminants into the distribution system from pressure transients,” j. water, health, 1, 3–14, (2003). • robert 1. sanks, ph.d. pe consulting engineer and professor emeritus montana state university bozeman, montana (1998). • strecker, f. and feldtkeller, r. grundlagen der theorie des allgemeinenvierpols. elektrische nachrichtentechnik, 6, 93, (1929). • streeter, v.l. and wylie, e.b., hydraulic transients. mcgraw-hill (1967). • wood, d. j., and funk, j. e. surge reference manual: computeranalysis of transient flow in pipe networks, university of kentucky,lexington, ky. (1996). table 1 pipe characteristics for case 1. pipe number length (m) diameter (mm) darcy friction minor loss 1 610 914 0.012 0 2 914 762 0.013 0 3 610 610 0.014 0 4 457 457 0.015 0 5 549 457 0.015 0 6 671 762 0.014 0 7 610 914 0.013 0 8 457 610 0.014 0 9 488 457 0.012 0 table 2 pipe characteristics for case 2. numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 221 pipe number length (m) diameter (mm) darcy friction minor losses 1 1,002.2 1.5 0.013 0 2 2,000.0 1.000 0.012 0 3 2,000.0 0.750 0.015 0 4 502.5 0.500 0.013 0 5 502.2 0.500 0.014 0 6 1,001.2 1.000 0.014 0 7 2,000.2 0.750 0.014 0 figure 1 method of characteristics. figure 2 numerical solution of method of characteristics. maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 222 figure 3 simple pipeline systems. figure 4 network with more apparatus. numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 223 figure 5 comparison of results of time domain and frequency domain methods, for case 1, at junction 4. figure 6 comparison of results of time domain and frequency domain methods, for case 1, upstream of valve. maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 224 figure 7 comparison of results of time domain and frequency domain methods, for case 2, at junction 2. figure 8 comparison of results of time domain and frequency domain methods, for case 2, upstream of valve at node 7. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 91 ciphering of text by using shfit register technique and its transmission over optical fiber abstract stream cipher is one of important branch of cryptography that can be implemented by using software and hard ware components .this system is divided into two types : 1.linear stream cipher system . 2. nonlinear stream cipher system . in this work, we deal with the two type of stream cipher system , the first type doesn’t have top secret degree due to weakness of the linear complexity for the sequence generated from linear feedback shift register (lfsr) .there are many algorithm ms that are designed by using the process of nonlinear combination for more than one linear shift register ,one of these algorithm ,that is called adder algorithm ,is used to generate a key sequence for encryption and deciphering process .the data in form of speech or waveform have been recorded by using computer microphone .these digital speech were encrypted .the encrypted speech has been sent via rs232 standard interface at a bit rate 19.6 kbps to another computer ,and then will be decrypted . the encrypted data were transmitted through the optical system .a multi mode optical fiber is used as a channel and pin photo diode is used as an optical detector. keyword: cipher, shift register, optical fiber, encryption, decryption. تشفیر لكالم نصي باستخدام تشفیر مولد المفاتیح وإرسالھ عبر لیف بصري الخالصة حیث تعتمد امنیتھا على درجة التعقید لمولد متتابعة المفاتیح ولذلك . تعتبر انظمة التشفیر االنسیابي من االنظمة الشفریة المھمة م تصامیم المولدات الخطیة والالخطیة وحساب التعقید الخطي شھدت ھذه االنظمة دراسات تحلیلیة وبحوث عدیدة في تقوی .للمتتابعات الناتجة عن المكافئات الخطیة لھذه المولدات الالخطیة یتناول ھذا البحث تصمیم وبناء خوارزمیات لمحاكاة مولدات مفاتیح خطیة والخطیة باشكال وتراكیب مختلفة وحساب التعقید یتم ارسال ھذه البیانات عن . مع رسائل نصیة باشكال مختلفة لتولید بیانات تشفیریة بصور مختلفة الخطي لھذه المولدات ودمجھا وفك تشفیرھا باستخدام تواخیرا یتم استالم ھذه البیانا طریق االلیاف البصریة بحسب مواصفاتھا والمعدة لھذا النوع من البیانات . االكثر مالئمة لھذه االنواع من التشفیر) ++c(تم استخدام لغة البرمجة . انواع المفاتیح mohanned hassan ali department engineering of technical electrical power technical college/ musayab haider j. abd departement of electrical engineering babylon university حیدر جبار عبد جامعة بابل\كلیة الھندسة قسم الھندسة ا الكھربائیة مھند حسن علي المسیب/الكلیة التقنیة قسم تقنیات ھندسة القدرة الكھربائیة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 92 introduction a communication is an important part of our daily lives .it helps us to get close to one another and exchange important information . the communication process involves information generation , transmission , reception , and interpretation (hioki,1998),(lubbe,1998). fiber optics is finding use in virtually every application involving the transmission of information .computer can now be link together with fiber optics cables capable of transmission data several orders of magnitude faster than copper circuit . the computer can now be found in all layers of our society and the possibilities for communication have grown immensely. cryptology is the science which concerned the method of providing secure storage and transportation of information it widest since . internal architecture and opertion of optical fiber an optical fiber is a cylindrical dielectric waveguide that transmits light along its axis, by the process of total internal reflection. the fiber consists of a core surrounded by a cladding layer. to confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding. the boundary between the core and cladding may either be abrupt, in step-index fiber, or gradual, in graded-index fiber. step-index multimode fiber (amon,1997) has a large core, up to 100 microns in diameter. as a result, some of the light rays that make up the digital pulse may travel a direct route, whereas others zigzag as they bounce off the cladding. these alternative pathways cause the different groupings of light rays, referred to as modes, to arrive separately at a receiving point. the pulse, an aggregate of different modes, begins to spread out, losing its welldefined shape. the need to leave spacing between pulses to prevent overlapping limits bandwidth that is, the amount of information that can be sent. consequently, this type of fiber is best suited for transmission over short distances, in an endoscope, for instance. graded-index multimode (gred,1984) fiber contains a core in which the refractive index diminishes gradually from the center axis out toward the cladding. the higher refractive index at the center makes the light rays moving down the axis advance more slowly than those near the cladding. also, rather than zigzagging off the cladding, light in the core curves helically because of the graded index, reducing its travel distance. the shortened path and the higher speed allow light at the periphery to arrive at a receiver at about the same time as the slow but straight rays in the core axis. the result: a digital pulse suffers less dispersion. there are two different types of optical fiber: multimode and single-mode. both are used in a broad range of telecommunications and data networking applications. these fiber types have dominated the commercial fiber market since the 1970’s. the distinguishing difference, and the basis for the naming of the fibers, is in the number of modes allowed to propagate in the core of a fiber. a “mode” is an allowable path for the light to travel down a fiber (john,1996). a multimode fiber allows many light propagation paths, while a single-mode fiber allows only one light path. in multimode fiber (piper,1982)the time it takes for light to travel through a fiber is different for each mode resulting in a spreading of the pulse at the output of the fiber referred to as inter modal dispersion. the difference in the time delay between the modes is called differential mode delay (dmd). inter modal dispersion limits multimode fiber bandwidth. this is significant because a fiber’s bandwidth determines its information carrying capacity, i.e., how far a transmission system can operate at a specified bit error rate .the optical fiber guides the light launched into the fiber core (figure.1). the cladding is a layer of material that surrounds the core. the cladding is designed so that the light launched into the core is contained in the core. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 93 components used in the optic fiber communication system 1. light source: light source is often considered to be the active component in an optical fiber transmission link. its fundamental function is to convert the electrical signal into a corresponding light signal that can be injected into the fiber .the common light sources for optical fiber system are semiconductor light sources , which are light emitting diode (led) and laser diode(ld) . comparison of the advantages of (led) and ld is shown in (table 1) (becker&piper,1982). light emitting diodes may be used with either multimode or single mode fibers when lower light levels and the lower information capacity (lower modulation bandwidth) are acceptable .laser diode achieve higher performance at the expense of higher cost and complexity. 2. light detectors: semiconductor based photodiodes are used as optical detectors in the optical fiber communication systems. they have small size, high sensitivity and fast response. there are two types of photodiodes which consists: 1. a positive-intrinsic-negative (p-i-n) photodiode consists of p and n regions separated by a very lightly n doped intrinsic region. silicon (p-i-n) photodiodes are used at 0.8 µm wavelength and ingaas (p-i-n )photodiodes are used at 1.3 µm and 1.55 µm wavelengths. in normal operation, the p-i-n photodiode is under high reverse bias voltage. so the intrinsic region of the diode is fully depleted of carriers. 2. avalanche photodiodes (apds): it consists of four regions p+ -ip-n+ in order to develop a very high electric field in the intrinsic region as well as to impart more energy to photoelectrons to produce new electron-hole pairs by impact ionization. types of encryption the simplest type is called secret-key or symmetric-key encryption where one key is used for both encryption and decryption. it is very fast but only useful for encrypting data that is not "going" anywhere. a security breach can take place because the sender and receiver of the date have to share the key .the second type of encryption is called public key encryption. this is an asymmetric scheme where there is a pair of keys that are used. there is a public key, which encrypts the data and a corresponding private (or secret) key for the decryption. this is often used in conjunction with a digital signature. the primary benefit is that it allows people to exchange messages securely without a preexisting security arrangement. all communications involve only public keys and the private key is never transmitted or shared. pretty good privacy is a combination of the secret-key and the private key encryption (robling,1982). it first compresses the data which strengthens the security by reducing the patterns associated with encryption. then it creates a session key that is a one time only secret key. the key is a random number generated by the keystrokes made and the movements of the mouse. the session key is used like the secret key to encrypt the data so it is very fast. the block diagram of the cryptography is shown in ( figure 2). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 94 the relationship between encryption and message plaintexts of length a positive multiple of some block length n if a message (m) is encrypted by the function of encryption (e) to yield a cipher text(c) or in the mathematical notation (schneier,1996) e(m) =c …………………………………………………………….(1) and we can recover (m) by appliance the function of the description (d) on the cipher text : d(c)=m ………………………………..………………………….(2) and we can obtained the message (m) by appliance the functions of the encryption and description on the plane text: d[e(m)]=m ………………………………….………………………(3) the link between algorithms and key the meaning of the algorithm is the mathematical function used for encryption and description. in the cipher system there are two types of the algorithm the first type using the same algorithm , in encryption and description, and the second type the algorithm which it is used in the encryption differs from the algorithm used in the description (harris). in the past time these algorithms have low security because that anyone can change the algorithm so to solve this problem they used keys. ek(m)=c ……………………………………..………….………(4) dk(c) =m …………………………………..………………….....(5) this key increasing the security of the algorithms then some type of algorithms used the same key in encryption and description and other type using different keys in encryption and description as shown ( figure 3 ): ek1(m)=c ……………………………………………………….. (6) dk2(c) =m …………………………………………..…………... (7) dk2[ek1(m)]=m …………………………………...…………...…….…(8) plaintext the transmitted information between the transmitter and the receiver units represent the plain text or original massage .this information represents the deduced information in a binary system . this work shown in ( figure 4 ). the stream cipher and blocking cipher the stream cipher is one that encrypts a digital data stream one bit or byte at the time (such that vigenere cipher (piper,1987), (kitab) ,the block cipher is one in which a block of plane text is treated as a whole and used to produce a cipher text block of equal length .block cipher can be used to achieve the same effect as a stream cipher. the stream represents the most using in the encryption system because of its important properties like high reliability and ease of use in practical application and high speed of execution.( figure 5) show stream cipher. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 95 the technique of stream cipher the operation of the stream cipher is that an algorithm is feeding by the key to produce the pseudo random sequence (piper,1982),(alhamadni,1997). this sequence is mixed with the plane text (which contains alphabet or data ………etc) to yield the cipher text.in the other way we can get the plane text from mixing the cipher text with the pseudo random sequence to produce the plane text. there are two types of the stream cipher , the first is periodic (the key stream repeats after character or bit) and the second is non periodic (which is used for one time only such as one -time pad cipher). a key stream generator outputs(2n-1)where n is the no. of register .a key stream of bits k1, k2 , k3, (electrical) …..ki (6) . this key stream is xored with a stream of plaintext bits :p1 ,p2, p3…pi. to produce the stream of cipher text bits. ci =pi+ki ………………………………………………………...(9) at the decryption end ,the cipher text bits are xored with an identical key stream to recover the plaintext bits . pi=ci+ki ……………………………………………………….(10) finally the system security depends only on the insides of the key stream generator (alhamadni & shakar,1995) types of stream ciphper system there are two basic kinds of stream cipher system: 1-linear stream cipher system: in this type the algorithm is a shift register with linear feedback function. in this type the algorithm is a shift register with linear feedback function as shown in ( figure 6 ) (arab). for this example the no. of register =3 and the initial value =101 and the length of key generator 23-1 =7 the key is (1011100). the plaintext is (take me to your leader) and we need to convert it to the askycode (binary number ). the cipher text is obtained by equation: ci =pi + ki the cipher text is: (000100000111010010111001100100100010011001000100000100110000101001001100010010001 110001000100110010011101001110000110000001110), and we can obtain the original plain text (take me to your leader) by equation below: pi =ci + ki the second example for shift register( linear stream cipher) is shown in ( figure 7 ) .in this type the number of register =5 ,and the length of key (25-1=32-1=31) the initial value =11011 and we take the plaintext (copy all items),and we need to convert this plaintext into askycode (binary number) .the key generator is (1101100011111001101001000010101). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 96 and we can get the cipher text by equation below ci =pi + ki the cipher text is: (010111011100011100100001101100111000001011010101000000011111111001110101100010111010). the original plaintext (copy all items) can be obtained by the equation pi = ci + ki 2-non linear stream cipher system: in this type the algorithm is different either one shift register with the combining function which is xoring or more than one shift register with combining function. this type shown in ( figure 8 ). for this example the no. of register =4 and the length of the key =24-1 =15 .and the initial values =1100 and the plain text (macdonald),and we need to convert it to asky code in (bainary number), the key generated outputs : (010110010001111).so the cipher text can be obtain from the equation below: ci =pi + ki the ciphertext is (110000100001100010101110011101001001011111011010000001000111110) and we can get the original plain text (macdonald) by the formula below: pi = ci + ki for another example on the nonlinear feedback we take the ( figure 9 ) this type consist of two linear shift register ,the first consist of two registers and its initial s1=1,s2=0.the length of key =22-1= 3 and the second consist of three registers and its initial values s3=1,s4=0,s5=1, and the length of the key (23-1=7) .the over all length of key out puts equal( 3*7=21)and is:(001001010000011010011). so the cipher text can be obtaind by: ci =pi + ki and cipher text is (1010000000110100100101010001000101000110111010011001011000110001010110000111000001001011100) . and we can get the original plain text (black hawk down ) by: pi = ci + ki results and discussion in this part, we deal with the program and results which is calculated in the previous part and key sequence generation from adder algorithm. and the ciphering of the plaintext and access the plaintext or original message from cipher text by deciphering process is discussed. 1. the cipher and deciphering process al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 97 using xor boolean function to make a bit wise operation between the plaintext or original message with a binary sequence generation from adder algorithm to obtain the cipher text, and we can access or recover the plaintext from the cipher text by xoring the cipher text and sequence generation from adder algorithm. the askycode of the alphabets shown in the ( table 2). for the (figure 6) (linear stream cipher) the no. of register =3. the initial value of the register are: s1=1, s2=0, s3=1. and length key generation =23-1=7 .the key is (1011100) as shown in the (table 3) the plain text is (take me to your leader).and the askycod for the plain text of our example and ciphering is shown in the (table 4). the cipher texts are: (0001000001110100101110011001001000100110010001000001001100001010010011000100100 01110001000100110010011101001110000110000001110). and we can obtain the original plain text (take me to your leader) by xoring the cipher text with the key generation. for the figure (1-7) (linear cipher type) the no. of registers =5. and the initial values in the registers s1=1, s2=1, s3=0, s4 =1, s5=1.and the length of the key generation is 25-1=31 as shown in the (table 5) the plain text (tom crouse). and the askycode for this example and ciphering are shown in the(table 6). the cipher text is: (0111000111000011111001000000100011110001000011001100110111101110). and we can obtain the original plaintext (tom crouse) by xoring the cipher text with the key generation. for the figure (1-8) (non linear cipher type) the no. of registers =4 .the initials values in the registers are s1=1 ,s2 =2 ,s3=0 ,s4=0 .the length of the key generation=241=15.as shown in the (table 7). the plain text (macdonald) and the askycode for this example and ciphering are shown in the (table 8).. the cipher text is (110000100001100010101110011101001001011111011010000001000111110). and we can obtain the original plaintext (macdonald) by xoring the cipher text with the key generation. for the (table 9). this type consists of two linear shift register, the first consist of two registers and its initial s1=1, s2=0.the length of key =22-1= 3 and the second consist of three registers and its initial values s3=1, s4=0,s5=1, and the length of the key (23-1=7).the over all length of key out puts equal ( 3*7=21) . the plain text (ali) and the askycode for this example and ciphering as shown in the (table 10). the cipher text is :-(101001100011010011010) and we can obtain the original plaintext (ali) can be obtained by xoring the cipher 2. software implementation: in this part the program was implemented using c++ language and matlab 7.0. the program represent the message as askycode of the alphabets and representscipher text (linear feedback shift register )and cipher text.(non linear feedback shift ).(figure 10) shows the flowchart of the load specification program. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 98 conclusions 1. use ciphering (lfsr) by optical fiber is more accurate and more secure than ciphering by other methods. 2. transmission of the information using laser is better and faster than other methods (linear stream cipher system). 3. the research was done by c++ , matlab, and flow charts in order to illustrate the method. references • bruce schneier ,"applied cryptography" second edition, john wiley and sons,inc.,1996. • dorothy elizabeth robling denning " cryptography and data security " addison-wesley publishing company , 1982. • farnell semiconductors data sheet cd-rom , sponsored by harris semiconductor . www .semi.com • heny beker and fred piper , "cipher systems " northwood publication, 1982. • keiser. gred , " optical fiber communications " , second edition , mc. grow hill ,1984. • piper f. c. , "stream ciphers" , cryptography :proceedings of the workshop on cryptography , germany , 1982. • piper , f.c.," cipher systems" , egham , england ,1987. • piper , f.c.," cipher systems",1982. • senior john m.," optical fiber communications principles and practice ", second edition, prentice hall ,1996. • the web site http: // www.kitab.com • the web sit http: //www. electricalsclub.com • the web sit http: // www.arab-engineering.com • van der lubbe , "basic methods of cryptography " , prentice hall ,1998. • waseem alhamadni "cipher systems ", baghdad ,1997. • waseem alhamadni & wasan shakar,’’ stream cipher system’’, baghdad ,1995. • warren hioki ,"telecommunication ", 3'rd edition , prentice hall ,1998. • yarif. amon, " optical electronics in modern communications", fifth edition, oxford university press, 1997. http://www.kitab.com http://www.arab-engineering.com al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 99 table(1) comparison of light sources laser diode light emitting diode property higher lower optical power shorter longer life time expensive cheap cost narrow wide line width higher lower modulation bandwidth long short distance table(2) the ascii of the alphabets ascii in binary ascii alphabet 1000001 65 a 1000010 66 b 1000011 67 c 1000100 68 d 1000101 69 e 1000110 70 f 1000111 71 g 1001000 72 h 1001001 73 i 1001010 74 j 1001011 75 k 1001100 76 l 111101 77 m 1001110 78 n 1001111 79 o 1010000 80 p 1010001 81 q 1010010 82 r 1010011 83 s 1010100 84 t 1010101 85 u 1010110 86 v 1010111 87 w 1011000 88 x 1011001 89 y 1011010 90 z al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 100 table (3) length key generation o/p s3 s2 s1 i/p ----- 1 0 1 initial 1 0 1 1 1 0 1 1 1 2 1 1 1 0 3 1 1 0 0 4 1 0 0 1 5 0 0 1 0 6 0 1 0 1 7 table (4) ascii for the plain text cipher text ascii in binary xor key ascii alphabet 0001000 1010100+1011100 84 t 0011101 1000001+1011100 65 a 0010111 1001011+1011100 75 k 0011001 1000101+1011100 69 e 0010001 1001101+1011100 77 m 0011001 1000101+1011100 69 e 0001000 1010100+1011100 84 t 0010011 1001111+1011100 79 o 0000101 1011001+1011100 89 y 0010011 1001111+1011100 79 o 0001001 1010101+1011100 85 u 0001110 1010010+1011100 82 r 0010001 1001100+1011100 76 l 0011001 1000101+1011100 69 e 0011101 1000001+1011100 65 a 0011100 1000100+1011100 68 d 0011000 1000101+1011100 69 e 0001110 1010010+1011100 82 r al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 101 table (5) length of the key generation o/p s5 s4 s3 s2 s1 i/p ------ 1 1 0 1 1 initial 1 1 0 1 1 0 1 1 0 1 1 0 0 2 0 1 1 0 0 0 3 1 1 0 0 0 1 4 1 0 0 0 1 1 5 0 0 0 1 1 1 6 0 0 1 1 1 1 7 0 1 1 1 1 1 8 1 1 1 1 1 0 9 1 1 1 1 0 0 10 1 1 1 0 0 1 11 1 1 0 0 1 1 12 1 0 0 1 1 0 13 0 0 1 1 0 1 14 0 1 1 0 1 0 15 1 1 0 1 0 0 16 1 0 1 0 0 1 17 0 1 0 0 1 0 18 1 0 0 1 0 0 19 0 0 1 0 0 0 20 0 1 0 0 0 0 21 1 0 0 0 0 1 22 0 0 0 0 1 0 23 0 0 0 1 0 1 24 0 0 1 0 1 0 25 0 1 0 1 0 1 26 1 0 1 0 1 1 27 0 1 0 1 1 1 28 1 0 1 1 1 0 29 0 1 1 1 0 1 30 1 1 1 0 1 1 31 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 102 table (6) the ascii and ciphering. cipher text ascii in binary xor key ascii alphabet 0111000 1010100+1101100 84 t 1110001 1001111+0111110 79 o 1111001 1001101+0110100 77 m 0000001 1000011+1000010 67 c 0001111 1011101+1010010 82 r 0001000 1000111+1001111 79 o 0110011 1010101+1100110 85 u 0011011 1001000+1010011 83 s 1101110 1000101+0101011 69 e table(7) length of the key generation o/p s4 s3 s2 s1 i/p ------ 0 0 1 1 initial 0 0 1 1 1 1 1 1 1 1 1 2 0 1 1 1 0 3 1 1 1 0 1 4 1 1 0 1 0 5 0 0 1 0 1 6 0 1 0 1 1 7 1 0 1 1 0 8 0 1 1 0 0 9 0 1 0 0 1 10 0 0 0 1 0 11 1 0 1 0 0 12 1 1 0 0 0 13 1 0 0 0 1 14 1 0 0 1 1 15 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 103 table (8) the ascii and ciphering cipher text ascii in binary xor key ascii alphabet 1100001 1001101+0101100 77 m 0000110 1000001+1000111 65 a 0010101 1000011+1010110 67 c 1100111 1000100+0100011 68 d 0100100 1001111+1101011 79 o 1011111 1001110+0010001 78 n 0110100 1000001+1110101 65 a 0000100 1001100+1001000 76 l 0111110 1000100+1111010 68 d table(9) length of the key generation. o/p s5 s4 s3 s2 s1 i/p ----- 1 0 1 0 1 initial 0 0 1 0 1 1 1 0 1 0 0 1 0 2 1 0 0 1 0 1 3 0 0 1 1 1 1 4 0 1 1 1 1 0 5 1 1 1 0 0 1 6 0 1 0 1 1 1 7 1 0 1 0 1 0 8 0 1 0 0 0 1 9 0 0 0 1 1 1 10 0 0 1 1 1 0 11 0 1 1 1 0 1 12 0 1 1 0 1 1 13 1 1 0 1 1 0 14 1 0 1 0 0 1 15 0 1 0 0 1 1 16 1 0 0 1 1 0 17 0 0 1 1 0 1 18 0 1 1 1 1 1 19 1 1 1 0 1 0 20 1 1 0 1 0 1 21 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 104 table (10) the ascii and ciphering. cipher text ascii in binary xor key ascii alphabet 1010011 1000001+0010010 65 a 0001101 1001100+1000001 76 l 0011010 1001001+1010011 73 i figure (1) optical fiber scheme (john, 1996) figure (2) block diagram of the cryptography (robling, 1982) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 105 figure (3) encryption and decryption with the different key figure (4) flowchart for converting the message to the digital data (harris) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 106 figure (5) the stream cipher (kitab) figure (6) linear feedback shift register with n=3 figure (7) linear feedback shift register with n=5 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 107 figure (8) non linear feedback shift register with n=3 figure (9) non linear feedback shift register with n=3 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 108 figure (10) the flowchart of the load specification program template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 120 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. study the effect of the particle size on mechanical properties of particulate natural composite materials israa faisal qhazi, department of materials engineering, college of engineering, university of al-qadisiyah. email: israa.faisalghazi@qu.edu.iq received on 30 october 2016 accepted on 23 january 2017 abstract: this research studied the mechanical properties of particulates composite materials made from natural fillers (eggshell and sawdust) reinforced epoxy resin. the composite specimens were prepared by hand lay-up technique with one volume fraction vf, and different particle size of fillers. modulus of elasticity, tensile strength, percentage of elongation and hardness were measured for each type of composite. the tensile tests results had shown an incremental increase with size of particles decreasing also hardness results had shown an incremental increase with smaller particle size. this work institutes a good substitution for synthetics fillers avoiding their highly cost and their toxicity, at the same time reducing of the environmental pollution.. keywords: natural fillers, particles size, mechanical properties, particulate composite materials. 1. introduction in previous years there is a necessity of materials with unconventional properties that satisfy an ever more difficult market show the way to the utilization of composite materials. for instance, composites use at automotive, aeronautic and civil construction. composite materials are multiphase materials that prove advanced properties than their individual phases, providing a synergistic effect. [1] from meaning, composites are materials be made of at least two chemically separate elements on a macro level with a different boundary separating them and having a good performance which is noticeably dissimilar from those of individual elements. the major phase of composite material is usually poor in stiffness, weak, more ductile and having a continuous character is called matrix. the matrix forms the large fraction in composite. the minor phase is a discontinuous form which is fixed in the matrix. the dispersed phase is normally stiffer and stronger than the matrix phase therefore is called reinforcement. it employs to reinforce the matrix and improves the mechanical performance of the matrix. [2] polymers which used as matrix materials consist of two main classes such as thermoplastics and thermosets. thermoplastics (polypropylene, nylons, acrylics etc.) by effect of heat they can be repeatedly softened and reformed. conversely, thermosets (phenolics, epoxies, unsaturated polyester etc.), are materials that experience a curing process through their production, behind which they are rigid and cannot be reformed. [1] in practice, for uses most polymers in engineering applications require greatly filled with protective particles. these particles provide to improve several important properties as well as density, strength mailto:israa.faisalghazi@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 121 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. modulus, thermal expansion, and thermal conductivity. for many years, material scientists create many studies covered composite systems, unexpectedly slight essential thoughtful present about the effects of the size, shape, distribution, surface chemical nature, and concentration of the filler particles on the mechanical and rheological performance of composite and polymers through the curing process. [3] inorganic materials frequently need chemical modifications to enhance the interface between filler and polymer. [4] the chemical modification acts as a connection between the inorganic filler and the organic polymer matrix. the connection must hold or link to the filler and in order must strongly attach with the polymer. [5] inorganic mineral fillers similar to calcium carbonate (cc), silica, and talc have achieved importance because inexpensive fillers for thermoplastics. [6] a late present engineering research recognized that the natural filler reinforced polymer composites, for the reason that natural fibers or "bio-fibers" involve several compensation over conventional polymer fillers for instance glass fiber, these comprise low-priced, little energy use, non-harsh nature, security in usage, light weight, potentially higher volume fraction, high specific properties, adding up to the importance of environmental factors,. [7] la mantia[8] classify these materials, which employ normal resources, like green composites. a green composites seeking-out for materials coming from renewable resources will be favorite as opposite to the exhaustible fossil products. 9] more studies had studied the effect of type and particle size of particles on physical and mechanical properties of composite materials. ahmed.r, 2004 [10] made an investigation into the properties for unsaturated polyester resin reinforced with rice husk. results showed that composite materials of rice husk gain better mechanical properties compared with composite prepared from unsaturated polyester resin without filler. m. mohammed , a. hadi ,2012,[11]calculated the ultimate tensile strength, modulus of elasticity, elongation at break, hardness, resilience and specific gravity for natural composite materials and study the effect of egg shells powder on these mechanical and physical properties of natural rubber(nr). the results of testing showed that the hardness and elastic modulus, specific weight improved with increasing of the powder. while it was observed that the tensile strength, elongation and resilience reduced with rising of powder ratio. s.b. hassan, v.s. aigbodion, 2013[12], fabricated particulate composites materials with a total of 2– 12 wt.% eggshell particles (es) additions. and the effects of (es) on the microstructures and properties of al–cu–mg/es particulate composites were examined. the physical and mechanical properties measured integrated: density, tensile strength, impact energy and hardness. the results discovered that the tensile strength and hardness were increased for uncarbonized es more than for carbonized es while the impact energy was decrease by 23.5% at 12 wt.% uncarbonized es and 24.67% at 12 wt.% carbonized es particles, respectively k. a. iyer, j. m. torkelson,2014,[13] prepared green composite materials from egg shell and used complex grinding–sieving and/or chemical modification to assist in dispersing es in polymers such as polypropylene (pp). the high-quality dispersion of filler guide to a principal raise in young’s modulus (87% enhance relative to orderly pp for 40 wt% es) and a fine enhance in hardness; results display drop in strength of yielding, elongation, and impact strength. ch. charoenwong, s.pisuchpen[14] , in that research, used four levels of rubber wood sawdust particle with sizes (<10, 10-20, 20-35 and > 35 meshes) with polymeric materials and prepared a medium density particleboards from. the modulus of rupture, modulus of elasticity, thickness swelling and water absorption were examined. it was established that the particles sizes really affected in the mechanical properties of boards but the resistance of water of boards was unfavorably affected by the particle sizes. it recommended that the finer the particles sizes, the weaker and the higher water resistance. 2. theoretical part 2.1. properties of used materials 2.1.1. matrix material (epoxy): one of the thermosetting polymers is epoxy resin that, prior to curing, has one or more active epoxide or oxirane groups at the end(s) of the molecule and a few repeated units in the middle of the molecule [15]. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 122 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. comparison with further materials, epoxy has many exclusive chemical and physical properties. epoxy resins be able to formed to have outstanding chemical resistance, excellent adhesion, high thermal and electrical resistance, low shrinkage, and good mechanical properties, for example high strength and toughness. these good properties effect in epoxy resins include wide applications in industry, packaging, aerospace, construction, etc. they have found significant applications as bonding and adhesives, protective coatings, electrical laminates, apparel finishes, fiber-reinforced plastics, flooring and paving, and composite pipes .mechanical properties of epoxy were showed in table (1) [16]. table (1): mechanical properties of epoxy properties glass transition temperature (tg) 120 130 °c tensile strength 85 n/mm² tensile modulus 10,500 n/mm² elongation at break 0.8% flexural strength 112 n/mm² flexural modulus 10,000 n/mm² compressive strength 190 n/mm² coefficient of linear thermal expansion 34 *10-6 k-1 water absorption 24 hours at 23°c 5-10 mg (0.06-0.068%) iso 62 (1980) 2.1.2. reinforcing materials: a : eggshell filler one of the bad environmental troubles, which have been scheduled universally, is chicken eggshell (es) is an aviculture byproduct, particularly in those countries where the egg production is fine developed. about 150,000 tons of this material is disposed in landfills only in the united state .eggshell has about 95% calcium carbonate in the form of calcite and 5% organic materials such as type x collagen, sulfated polysaccharides, and other proteins[table 2] [17,18]. though there have been some efforts to employ eggshell components for unusual submissions [19–20]. along with further properties, that egg shell has light weight contrast to mineral calcium carbonate (values of density got by astm 679 are 0.4236 g/cm3 for eggshell put side by side with 0.4670 g/cm3 of commercial calcium carbonate or 0.4581 g/cm3 of talk). these characteristics succeed eggshell as an excellent applicant for bulk quantity, low-cost and low load-bearing composite applications, such as the automotive industry, trucks, homes, offices, and factories. the chemical composition of eggshell investigated by using x-ray fluorescence spectrometer was listed at table (2) [21] b : saw dust filler the waste sawdust is a significant source of raw material. faostat (food and agriculture organization of the united nations) wrote a report that explains that the quantity of diverse types of wood cut by sawmills is about 125.36 million m3only in europe in the year 2010 [22]. the sawdust losses resulting from sawing processes are between 5-11% of the total log volume. at a least loss value of 5% results in a volume of 6.27 million m3 sawdust. as result sawdust is a significant renewable raw material and be able to utilize in modern functions additionally than heating. lignocelluloses fibers have a set of advantages as contrast with conventional glass fibers utilized to al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 123 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (2): chemical composition of the eggshell strengthen composite materials. their ecological character, biodegradability, low-priced non-abrasive nature, safe treatment, use with various possibilities as fillers, processing with low power consumption, vital properties, low density and a large number of types of fiber are very important factors for their receiving in markets where a large amount of materials is required such as automotive industry. on the other hand certain disadvantages, such as the tendency of agglomeration throughout manufacture, low resistance to moisture and quality changes due to the seasons of growth, reduce the potential for these fibers [23, 24]. the chemical composition of saw dust was listed at table (3) [25] table (3): chemical composition of the wood powder 3. experimental procedure 3.1. materials the essential materials used in the preparation of samples in this research consisting of epoxy resin , with a density of (1.2 gm / cm3) made in jordan in the shape of transparent viscous liquid at room temperature which is a thermally hardened polymers (thermosets). the powder was used were egg shell (30, 50 and 100μm), and wood powder (sawdust) (30, 50 and 100μm) as shown in figure (1). 3.2. preparation of natural materials a: eggshell powder the eggshell used in this research was brown eggshell that they were collected and washed and sun chemical composition concentration (%) al2o3 0.001 sio2 0.001 s 0.001 cl 0.009 cao 99.83 cr2o3 0.003 mno 0.001 cuo 0.001 loi 0.153 chemical composition concentration (%) cellulose 47% lignin 21% hemicellulose and other compounds 30% extractives 2% ash 0.4% al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 124 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. dried to remove the membranes, crushed, grinded by milling machine and then the set of sieves employed to obtain a powder of egg shells in the variously size. figure (1): the eggshell and sawdust powder before and after milling b: wood powder (sawdust) wood powder is a consequence of cutting, grinding, drilling of wood with a saw or other tool; subsequently, sawdust was screened to three levels by sieving with screens having 30, 50, and 100 μm openings and oven-dried to less than 5% moisture content.the powder that using in this work was shown in figure (1). 3.3. preparation of samples moulds required for obtaining the samples were prepared from glass with dimensions of (200×250×5) mm. the internal face of the mould was covered with a thin layer of nylon (thermal paper) made from polyvinyl alcohol (pva) so as to avoid sticking between cast material and the mould as shown in figure (2). figure (2): the shape of the prepared mould. the technique applied in the preparation of the specimens, in this study is the (hand lay-up molding) by addition the epoxy with the hardener and mixing it continuously and slowly by using a glass rod to keep away from forming the bubbles. and adding the powder intermittently into the mixture and moving it for a period of (10-15) minutes to achieve homogeneity. it is very essential that the mixture must have a good viscosity for the purpose of al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 125 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. protecting the particles from precipitation which may result in the heterogeneity of the mixture that leads to the agglomeration after hardening. for the purpose of completing the process of hardening, finally is leaving the sample in the mould for a period of (24) hour at room temperature. samples are then extracted from the mould and then heat treated in an oven at (60°ċ) for a period of (60) minutes. this process is very important for the purpose of obtaining the best cross linking between polymeric chains, and to remove the stresses generated from the preparation process and complete the full hardening of the samples.[26] 3.4. equipment the equipment used in this study included: ball milling machine, sieves, measuring cylinder of 200 ml capacity, furnace, a digital weighing balance, molding (casting) boxes, universal tensile testing machine, and a digital hardness instrument. mechanical test tensile test tensile test is widely used to provide the designer with information about material strength and maximum elongation and others. the stress used in such curve is a longitudinal stress in test specimen and expressed as: σ = p/a ………………………….. (1) where: σ: longitudinal stress for specimen (mpa). p: applied load (n). a: original cross sectional area before testing (m 2 ). the strain which is used in such stress-strain curve is a linear strain and can be expressed as: l l  ..…………...…. (2) where:  : strain. lll  l : the final length (m). l : the original length (m). from the tensile curve, the following can be calculated: 1. tensile strength (mpa). 2. modulus of elasticity (mpa). 3. elongation percentage at break (%). this test is performed according to (astm d638m87b) at room temperature [27]. the used tensile machine is (instron 1195, made in england). figure (3) shows a standard specimen for tensile test. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 126 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3): tensile specimens and test instrument hardness test (shore d) this test is performed by using hardness (shore d) and according to (astm d-2240) standard at room temperature [28]. samples have been cut into a disk with diameter (40 mm) and (5 mm) as thickness. figure (4) shows hardness device and sample used in this research. for each specimen five hardness measurements were taken and the average hardness is calculated. figure (4): hardness specimens and test instrument 4. results and discussion 4.1. tensile test tensile test was executed on the specimen prepared from epoxy before and after adding the particulate fillers of the two types. curves of tensile test are illustrated in figures (5) to (9). al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 127 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figures (5) and (6) illustrate that the addition of ( eggshell +sawdust) powder in (6 %) volume fraction respectively. where at the same fillers volume fraction leads to increased the tensile strength with decreasing particles size. such behavior is due to the nature of bonding force between the matrix and fillers particles which is strong bonding in case of small particle size that does not allow forming internal defects (cracks) in quick manner and in turn the composite material will have high tensile strength.[29] figure (5,6): stressstrain curve of epoxy resin reinforced with eggshell and sawdust fillers at volume fraction of (6 %) and particles size (30-100) µm. the relationship between the modulus of elasticity and the particles size of reinforcement fillers is shown in figure (7). from this figure, it be able to be seen that small particles of reinforcing fillers improve the modulus of elasticity more than large particles, this is due to the strengthening mechanism as follows firstly: large particles strengthening for reinforcing fillers tend to restrain the movement of the matrix phase in the area of each particles, whereas the matrix transfers some of the applied load to the particles and bear fraction of it, and secondly: the small fillers hinder or impede slipping of matrix chains and require high stress to bow them in narrow space among particles compared with large particles of fillers and the matrix bears the major portion of the applied load [29]. both egg shell, and saw dust powder enhanced the tensile modulus of epoxy. however, egg shell powder was superior to saw dust powder in increasing the modulus of elasticity of epoxy. where, it can be noted the modulus of elasticity for eggshell fillers composite is higher than that for the sawdust fillers composites, where the maximum values are ( 1.48 and 1.37 gpa) at (25 µm) for eggshell and sawdust fillers respectively.[21] figure (8) shows the relationship between the tensile strength and the size of the filler particles .the figure illustrates that, the tensile strength increases with decreasing particles size, where the smallest particle size has a noticeable effect on the tensile strength more than the large particles due to the same reason mentioned before. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 128 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (7): the relationship between the modulus of elasticity and particle size for epoxy resin filled by eggshell and sawdust fillers. and it can be seen clearly that the strengthening by egg shell powder is more active than by sawdust, so that the tensile strength at (30 µm) particles size reaches (29 and 26.5 mpa), while (24.2 and 22.5 mpa) are at (100 µm) for eggshell and sawdust fillers composite respectively figure (8): the relationship between the tensile strength and particle size for epoxy resin filled by eggshell and sawdust fillers. 0 20 40 60 80 100 particle size ( m) 1.1 1.2 1.3 1.4 1.5 m o d u lu s o f e la s ti c it y ( g p a ) modulus of elasticity sawdust filler eggshell filler 20 40 60 80 100 particle size ( m) 20 24 28 32 t en si le s tr en g th ( m p a) tensile strength eggshell filler sawdust filler al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 129 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (9): the relationship between the elongation percentage and particle size for epoxy resin filled by eggshell and sawdust fillers. figure (9) shows the relationship between the elongation percentage calculated at break point and the size of the filler particles of prepared composite materials. it could be observed from this figure that the finer particle size increases the elongation percentage at break more than larger particles size of two types of reinforcing fillers; this is due to the nature of bonding force between the matrix and fillers particles. also, the composite material filled with eggshell filler particles has higher elongation percentage than the other which was filled with sawdust filler particles. 4.2. hardness shore (d) hardness test type shore (d) has been carried out on epoxy before and after powder fillers were added and the average of five readings in each case was taken to obtain higher accuracy results. table (4) shows the hardness values shore (d) for the prepared specimens (pure epoxy, epoxy +6% natural powder) composites. figure (10) shows the effect of filler type and particle sizes on the hardness of filled epoxy. the hardness of unfilled epoxy is 61 (shore d). the figure shows that the hardness of all filled epoxy at a given filler particle size increased more than pure epoxy. , this may be due to the fact that the hardness is generally considered to be a property of the surface therefore this behavior of hardness is expected. the addition of the filler leads to an increase in the elasticity and the matrix surface resistance to the indentation [30], thus specimen (epoxy +6% powder filler) have higher hardness than specimen with pure epoxy. the explanation of such behavior agrees with the results of modulus of elasticity because hardness gives indication to modulus of elasticity for polymer under simple strain condition. 20 40 60 80 100 particle size ( m) 1.6 2.0 2.4 e lo n g a ti o n a t b re a k ( % ) elongation (%) eggshell filler sawdust filler al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 130 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (4): hardness of the prepared composites specimens specimens hardness shore(d) pure epoxy 61 epoxy +egg shell (30m) 86.4 epoxy +egg shell (50m) 82 epoxy +egg shell (100m) 78.4 epoxy +sawdust (30m) 79 epoxy +sawdust (50m) 77.2 epoxy +sawdust (100m) 75.4 such increases in composites hardness with increase in filler content have been reported by chakraborty et al [31], and igwe and njoku[32]. generally, the hardness of all the composites decreased with increase in the filler particle size at any type of filler had used. at any given filler particle size considered, the order in the enhancement of hardness of epoxy is egg shell > sawdust powder. figure (10): the relationship between the hardness and particle size for epoxy resin filled by eggshell and sawdust fillers. 5. conclclusions 1. the addition of the reinforcing fillers (eggshell + sawdust) to the epoxy polymer leads to develop the mechanical properties. 2. ultimate tensile strength, modulus of elasticity and elongation percentages at break for two types of fillers increase with the addition of the reinforcing fillers. the small fillers improve the tensile properties 20 40 60 80 100 particle size ( m) 70 75 80 85 90 h a rd n e s s ( s h o re d ) hardness eggshell filler sawdust filler al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 131 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. of pure epoxy more than large fillers. where it reach the maximum value at ( epoxy +6% eggshell in 30 μm particle size) 3. result shows that the best hardness value for prepared composite material of ( epoxy +6% eggshell in 30 μm particle size) was (86.4 shore d) also it mean that the hardness of the prepared composite material increases with the decreasing in the size of particle of two fillers. 4. from result can be noted that the best properties value for epoxy composite materials are improved by using eggshell particle when compared with sawdust particles uses. 5. the use of egg shell, and sawdust powder as fillers for the plastic industry will not only provide a renewable source of filler for the plastic industry but also generate a non – food source of economic development for the famers in the rural areas. references 1. w. d. callister," materials science and engineering an introduction", 7ª ed. ltc – livros técnicos e científicos editora s.a. rio de janeiro, rj. 2007. 2. mohanty a.k.,wibowo, a., misra, m. and drzal, l.t., "effect of process engineering on the performance of natural fiber reinforced cellulose acetate biocomposites", composite part a: applied science and manufacturing, vol.(35), pp.(363-370), (2003). 3. j.a. emerson; j.g. curro and f. b. swol; "optimization of polymer filler materials" sandia national laboratories, usa, sandia report, sand2001-1108; april 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" biomineralization and eggshells: cell-mediated acellular compartments of mineralized extracellular matrix."rev. cytol. 145 (1993) 217. 18. j.l. arias, m.s. fernandez, mater. charact. " effect of crosslinked chitosan as a constrained volume on the in vitro calcium carbonate crystallization 50 (2003) 189. 19. s.i. ishikawa, k. suyama, k. arihara, m. itoh, bioresour. technol. 81 (2002) 201. 20. f. yi, z.x. guo, l.x. zhang, j. yu, q. li, biomaterials 25 (2004) 4591. 21. nasif,r.a.,2015 "preparation and characterization of eggshell powder (esp)and study its effect on unsaturated polyester composite material",iraqi journal of applied physics,vol11,no.1, ,pp.25-28. 22. food and agriculture organization of the united nations: [www] http://faostat.fao.org. (21.01.2012). 23. terciu, o. m., curtu, i., cerbu, c., stan, g. i., the 8th international conference “wood science and engineering in the third millenium, icwse 2011, 2011, brasov, romania, issn 1843-2689, pp. 345-352; 24. terciu, o.m., curtu, i., cerbu, c., stanciu, m.d., "mechanical properties of composites reinforced with natural fiber fabrics", in annals of daaam for 2011 & proceedings of the 22th international daaam symposium intelligent manufacturing & automation, editor katalinic b., 2011, issn 17269679, pp. 607-608; 25. a. basim, e. al-hassani ,"effect of nature materials powders on mechanical and physical properties of glass fiber / epoxy composite"eng. &tech.journal, vol.33,part (a), no.1,2015,p175197. 26. felix k., sylvester a. and edmund a.,"storage and handling techniques of maize and groundnut", senra academic publishers, burnaby, british columbia, no. 3,vol. 6, pp.2122, (2012). 27. annual book of astm standard, "standard test method for tensile properties of plastics d638m 87b", vol. 09.01 (1988). 28. annual book of astm standard "standard test method for plastics properties-durometer hardness d 2240", vol. 09.01, (1988). 29. w.a. wood, "the study of metal structure and their mechanical properties" perg amon press, (1977). 30. waffaa abed alkazem zkaer " determination of some mechanical properties of unsaturated polyester reinforced with glass fiber and plam fiber" engineering &technology journal , no.16 , vol.29, pp.3313-3319 ,(2011) 31. chakraborty s.k., setua k.k. and de s.k. (1982). rubber chem. technol. 55, 1286 1307. 32. igwe i.o. and njoku c. (2008). int. j. phys. sci. 3(4), 16. <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 11 prediction of ultimate load of concrete beams reinforced with frp bars using artificial neural networks ahmed sagban saadoon, basrah univ., civil eng. dept., ahmsag@gmail.com hawraa sami malik basrah univ., civil eng. dept., wesamsalm85@gmail.com received on 09 october 2016 accepted on 22 december 2016 abstract artificial neural networks (ann) were used in this study to predict ultimate load of simply supported concrete beams reinforced with frp bars under four point loading. a proposed neural model was used to predict the ultimate load of these beams. a total number of (199) beams (samples) were collected as data set and it was decided to use eight input variables, representing the dimensions of beams and properties of concrete and frp bars, while the output variable was only the ultimate load of these beams. it was found that the use of 11 and 10 nodes in the two hidden layers was very efficient for predicting the ultimate load. the obtained results were compared with available experimental results and with the aci 440.1r specifications. the proposed neural model gave very good predictions and more accurate results than the aci 440.1r approach. the overall average error, in the value of the predicted ultimate load, was 3.6% and 21.7% for the proposed neural model and the aci 440.1r approach, respectively. key words: frp bars, flexural behavior, artificial neural networks. تقدیر الحمل األقصى للعتبات الخرسانیّة المسلّحة بقضبان بولیمیریّة باستخدام الشبكات العصبیّة االصطناعیّة ahmsag@gmail.comجامعة البصرة، العراق، ,قسم الھندسة المدنیة ,احمد صكبان سعدون wesamsalm85@gmail.comعراق، ال ,جامعة البصرة ,قسم الھندسة المدنیة , حوراء سامي مالك الخالصة لقد تّم استخدام الشبكات العصبیّة االصطناعیّة في ھذه الدراسة لتقدیر الحمل األقصى للعتبات الخرسانیّة بسیطة اإلسناد والمسلّحة الحمل األقصى لھذه بقضبان تسلیح بولیمیریّة والمعّرضة الى تحمیل نقطي رباعي. حیث تّم إقتراح وتطویر شبكة عصبیّة لتقدیر ) نموذج كقاعدة بیانات. وقد تقّرر أْن یكون عدد متغیّرات اإلدخال لھذه الشبكة ھو ثمان متغیّرات ١٩٩العتبات وقد ُجمعت نتائج ( تمثّل أبعاد العتبات وخواص الخرسانة وقضبان التسلیح، في حین كان ھناك متغیّراً وحیداً ھو الحمل األقصى كمتغیّر إخراج. لقد عقد في الطبقة الثانیة كان فّعاالً جّداً في تقدیر ١٠عقدة (خلیّة عصبیّة) في الطبقة المخفیّة االولى من الشبكة و ١١ُوجد بأّن اختیار aci 440.1rقیمة الحمل األقصى. وقد قُورنت النتائج المستحصلة مع نتائج عملیّة متوفّرة ومع مواصفات المدّونة األمریكیّة لشبكة المقترحة نتائج أكثر دقّة من المدّونة األمریكیّة، إذ كان مقدار معّدل الخطأ الكلّي في قیمة الحمل األقصى المقّدر حیث أعطت ا % باستخدام المدّونة األمریكیّة.٢١.٧% باستخدام الشبكة المقترحة بینما كان مقداره ٣.٦ھو nomenclature a shear span (mm) a summation function af area of frp bar (mm 2 ) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 12 aci american concrete institute ann artificial neural network b width of beam (mm) or bias ef frp elasticity modulus (mpa) f activation function f’c compressive strength of concrete (mpa) fu frp tensile strength (mpa) fov fraction of variance frp fiber reinforcement polymer h beam’s depth (mm) l beam’s length (mm) logsic logistic sigmoidal function m shear span ratio (a/l) mae mean absolute error mape mean absolute percentage error mse mean square error n number of input samples (vectors) p ultimate load (kn) paci ultimate load predicated by aci code (kn) pann ultimate load predicated by neural network (kn) pexp experimental ultimate load (kn) purelin linear function r coefficient of correlation rmse root mean squared error tansig hyperbolic tangent function u actual value v predicted value u mean of the actual values w weight vector x neural input y neural output 1 general the ultimate strength in reinforcing members is depending on the type of reinforcement materials. due to durability and corrosion problem of steel reinforcement under aggressive conditions, other materials, like fiber reinforcement polymers (frp), have appeared to be an alternative reinforcement material. the frp reinforcing bars are a composite materials made of reinforcing fibers and a matrix (resin). frp composites are used in many types of engineering structures and can be used for enhancing requirements of performance due to their advantageous properties. frp composites are utilized in rehabilitation, formwork, and reinforcement for seismic design [jain and lee, 2012]. frp reinforced concrete members started to be used all over the world, specifically in areas like flexural behavior, bond performance, column behavior and shear behavior. in structural applications, frp are available as plates, strips or sheets, and reinforcing bars. the use of frp can be either as an alternative reinforcing instead of steel or for retrofitting to strengthening existing structures. frp are used as internal or external reinforcement to strengthen columns, slabs, and beams. the strength of these members can be increased even after their damage due to subjected loading. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 13 many experimental and theoretical investigations [6, 11, 15, 18, and 29] were performed to study the structural and flexural behavior of frp reinforced concrete beams. these beams are expected to undergo larger deformations than corresponding steel reinforced beams, since the modulus of elasticity of frp bars is low. frp bars have high ultimate strength and a linear stressstrain response. this would lead to an almost linear load-deflection response beyond the crack formation phase, up to failure. in this study, an attempt is made to get and predict the ultimate load of frp reinforced concrete beams using artificial neural networks. 2 artificial neural networks (ann) anns are computational networks which simulating a biological neural network. due to this, they allow using simple and basic operations to solve nonlinear or complex problems [graupe, 2007]. neural networks are considered good for regression and classification tasks in practical cases [begg et al., 2006]. this makes ann a very efficient tool to solve and deal with many structural and civil engineering problems [see 21, 24, and 31], particularly in problems having complex or insufficient data. basically, all anns have the same structure or topology, the most common arrangement of the neurons by using a series of layers as shown in figure (1). the first layer is the layer of input. the input units at this layer is dictated by the number of independent variables or feature values and the input data are taken either directly from electronic sensors or from input files. the final layer is the output layer which its units depend on the number of values or classes to be predicated and it sends information to the outside world or other devices like a mechanical control system, or a secondary computer system. the intermediate layers are called the hidden layers which contain many neurons in different interconnection structures. figure (2) shows the scheme of a model of an artificial neuron. the shown model has n number of input and one output. the body of neuron contains the summing junction (∑) and the activation function f. the following parameters and variables are used in the artificial neurons. every input has its own weight, which gives it the effect that it requires to process elements summation function. the node's internal bias (b) is a constant component represents the magnitude offset that affects the activation of the node output. the input vector and the weights vector can be represented as (x1, x2, ….., xn) and (w1, w2, ……, wn), respectively. the summation function can be calculated by multiplying of vector x and w and then adding up the products: å += = n 1i ii b)x(wa , (1) the result will be as a single number. this weighted sum, from summation function, is transformed to the working output though an algorithmic process called transfer function. when neurons are sufficiently activated its output will take a value of 1, but it take zero when the neuron is not sufficiently activated. there are many activation functions used in neural networks which specify the neuron output to a given input. 3 development of proposed neural model an artificial neural model is proposed to predict the ultimate load of simply supported frp reinforced concrete beams under four point loading as shown in figure (3). the neural network program that is implemented in matlab version 8.3.0.532 (r2014a) is used for performing the neural network in this study. this program has many advantages such as containing several types of networks and implementing many different training algorithms. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 14 back-propagation neural networks are proposed to study the relations between the input variables and the output variables by using the feed-forward back-propagation algorithm. the trial and error process is used to configure and train the neural networks for their indeterminate parameters such as the hidden layers and their nodes, learning patterns, and training parameters. 3.1 selection of data set the purpose of training a network is to allow it to produce accurate answers and generalize future data. the experimental data used in modeling the proposed neural model are subdivided into two groups; training and testing group. the network uses the training group to updating values of the nodes’ biases and weights in order to minimize the training error. in other words, it uses this group to get the relationship between the input and output variables. while the network uses the testing group to check the generalization ability of the proposed model. the total actual (experimental) data used in the proposed neural model are those obtained from available open literature [1, 2, 4-13, 15-18, 20, 22, 25-30, and 32-40]. a total number of (199) beams (samples) were collected as data set. the training group must contain the extreme values of the different input parameters of the total data set. for estimating the generalization capacity of the training process, the testing set is either selected rotationally from the total data set, or is selected randomly by the computer. in this study, the testing group comprises of approximately (20)% of the collected data and is selected randomly over the entire region of data set. accordingly, the training group is decided to comprise of (159) samples, while the testing group is comprised of (40) samples. 3.2 defining of input and output variables the problem’s nature is the effective factor that state the defining of the input and output variables (parameters). selection of the input variables is important to get an efficient network, while the selection of the output variables depends on what required from the network to know. in this study, the dimensions and properties of concrete and frp bars are chosen as candidate input variables. while the output variable is only the ultimate load (p) of the considered concrete beams. for the proposed neural model, it is decided to use the following eight variables as input variables: the cross sectional width (b) of beams, cross sectional depth (h) of beams, cylinder concrete compressive strength (f’c), cross sectional area of frp bars (af), frp bars tensile strength (fu), frp bars elasticity modulus (ef), effective span length (l) of beams, and shear span ratio (m). to minimize the input variables several attempts are tried to choose their proper number to represent the properties of the considered beams. in one attempt, the gross cross sectional area of concrete is used instead of its width and depth. also in another attempt, the reinforcement ratio of frp bars is used as an input variable. although good performance in training is found, but the generalization is very poor. therefore, it is decided to use the above eight input variables for the proposed model. so, eight nodes in the input layer and (1) node in the output layer are used in the proposed neural model. the ranges of all variables are given in table (1). 3.3 hidden layers and their nodes determining of hidden layers and their nodes depends on the network application. there is no rules available to find out their exact number. once start with small number and then is increased until the wanted value from the model (network) is reached. this number is chosen by a trial and error process. if the nodes number is large, the operation of network will be slow and may cause overfitting in the testing group performance. and if this number is very small then the network may be unable to learn well. the suitable number will be selected by a trial and error process to get the network of the minimum error (the best performance) for both training and testing group. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 15 firstly, a proposed levenberg-marquardt back-propagation neural network is investigated with different configurations to choose the best network. many different trial networks are trained and the optimal topology is determined by choosing the best performed network (of the less training error). trial networks with single and multi hidden layers and nodes and with a various activation functions (hyperbolic tangent (tansig), logistic sigmoidal (logsig), and linear (purelin) function) are tested. the results show that, the (11-10) two hidden layered model gives best performance with least error in the output variable. this network, with ten nodes in the first hidden layers and twelve nodes in the second and with tansig function for hidden layers and purelin function for the output layer, gives the best performance with mse of (0.000445) for the training group and (0.001069) for the testing group and number of epochs of (616). thus, this configuration (topology) is adopted to the proposed network. the topology of this neural network are shown in figure (4). while the properties of this proposed model are shown in table (2). 4. results and discussion a regression analysis between the obtained (predicted) results and the actual values is performed to investigate the accuracy of the proposed network. the regression coefficient of correlation (r) is used as an index in this analysis. if (r) is close to a value of one, then there is an excellent correlation between the obtained (predicted) loads and the actual loads. figure (5) shows the correlation analysis of the proposed model output and the experimental values for the training group, while figure (6) shows this analysis for the testing and group. from figure (5), which represents the regression analysis for the training data, the correlation coefficient (r) is (0.9988), the interception with y-axis is (0.307) and the slope is (0.997). while for the testing data, figure (6), the correlation coefficient (r) is (0.9961), interception with y-axis is (0.863) and the slope is (0.991). these analyses certify good agreement between the obtained results and the actual results. 5. comparative study the proposed neural model is used to obtain and predict the ultimate load of the frp reinforced concrete beams that used in the selected testing set of this study. a comparison between the experimental and predicted ultimate loads obtained by the proposed model (pann) and those obtained from using the aci 440.1r approach [3] (paci) is presented in table (3). as can be noticed from this table, for almost specimens the proposed network gives more accurate results as compared with those predicted by the aci 440.1r approach. the aci 440.1r approach underestimates ultimate loads up to approximately 50% (beam number 17) and overestimates ultimate loads up to approximately 24% (beam number 27). while the proposed neural model underestimates ultimate loads up to approximately 12% (beam number 17) and overestimates ultimate loads up to approximately 8% (beam number 10). a statistical comparison between the actual and predicted loads is also performed to check the accuracy of the proposed network and the aci 440.1r approach of ultimate load calculation as shown in table (4). four indices are used in this study to comparative evaluation of the behavior of the proposed network and the calculated ultimate loads using the aci 440.1r specifications. these indices are the mean absolute error (mae), root mean squared error (rmse), mean absolute percentage error (mape), and fraction of variance (fov). and they are given, respectively, as: å -= = n 1i vu n 1 mae , (2) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 16 2 n 1i )vu( n 1 rmse -å= = , (3) 100u/)vu( n 1 mape n 1i ´å -= ú û ù ê ë é = , (4) )uu(/)vu(1fov n 1i 2 n 1i -å-å-= == , (5) where u is the actual value, v is the predicted value, u is the mean of the actual values, and n is number of specimens. if mae is 0, rmse is 0, mape is 0, and fov is 1, then the used model will be excellent. as can be noticed from table (4), the mae, rmse, mape, and fov for the ultimate load prediction of the proposed neural model are (4.4, 5.7, 3.6, and 0.992), respectively. while these values for the aci 440.1r approach are (31.4, 41.7, 21.7, and 0.582), respectively. these values proved that the proposed neural model prediction is satisfactory indicating that, an excellent agreement with the experimental data is obtained and hence the proposed network can obtain and predict loads very well and better than aci 440.1r approach. in figure (7), the predicted ultimate loads obtained by the proposed model (pann) and the aci 440.1r approach (paci) are plotted against the actual loads. from this figure, it is obvious that in general the aci approach underestimates the value of the ultimate load. the coefficient of correlation r = 0.9961 and 0.7629 for pann and paci, respectively. these values show that the proposed neural model predicts loads much better than the aci approach. therefore, with an overall average error of 3.6%, it is concluded that the developed network could be used efficiently in obtaining the ultimate loads and that the ann provided an alternative procedure to the costly test procedures for the ultimate load prediction of frp reinforced concrete beams. 6. conclusions the main important points that can be concluded from this study are as follows: 1. the artificial neural networks (ann) have been proved its capability in predicting the ultimate load of frp reinforced concrete beams, and it could be used this procedure as a reliable alternative to other complex or costly test procedures. 2. the proposed neural model, in the current study, has been found to be very excellent for prediction of the ultimate load of frp reinforced concrete beams. 3. the configuration (11-10) for the proposed neural model was found to be very typical for prediction of the ultimate load of frp reinforced concrete beams. 4. the overall average error, in ultimate load prediction, was 3.6% and 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building materials, 25, p. 2391– 2401. 38. yost j. r., goodspeed c. h., and schmeckpeper e. r., 2001, ''flexural performance of concrete beams reinforced with frp grids'', journal of composites for construction, vol. 5, no. 1, p. 18-25. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 20 39. yuan f., pan j., and leung c. k. y., 2013, ''flexural behaviors of ecc and concrete/ecc composite beams reinforced with basalt fiber reinforced polymer'', journal of composites for construction , vol, 17, no. 5, p. 591-602. 40. zhang l., sun y., and xiong w., 2014, ''experimental study on the flexural deflections of concrete beam reinforced with basalt frp bars'', materials and structures. table (1) input and output variables variable range input variables: width of beam, b, (mm) 80 – 500 depth of beam, h, (mm) 100 – 590 concrete compressive strength, f'c, (mpa) 13.7 – 85.6 area of frp bars, af, (mm 2 ) 39.3 – 19635 frp bars tensile strength, fu, (mpa) 126.2 – 2250 frp bars elasticity modulus, ef, (mpa) 30000 – 200000 length of beam, l, (mm) 400 – 4200 shear span ratio, m 0.273 – 0.47 output variable: ultimate load, p, (kn) 16 – 365.4 table (2) properties of the proposed neural model network nodes in 1 st hidden layer nodes in 2 nd hidden layer nodes in output layer epochs mse for training set mse for testing set 11 – 10 11 10 1 616 0.000445 0.001069 table (3) actual and predicted ultimate load beam no. type of frp bars concrete compressive strength, f’c (mpa) frp reinforcement ratio to balanced ratio, (ef / ebf ) ultimate load (kn) pann /pexp paci /pexp actual pexp predicted by by al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 21 ann pann aci paci 1 gfrp 24.5 2.67 75.2 74.2 42.5 0.987 0.565 2 gfrp 30.0 1.99 96.0 96.3 79.2 1.003 0.825 3 gfrp 27.6 0.42 33.7 33.9 31.6 1.006 0.938 4 gfrp 27.6 0.69 51.2 53.4 62.5 1.043 1.221 5 gfrp 38 4.05 40.7 40.5 34.7 0.995 0.853 6 gfrp 27.6 4.30 41.6 41.2 33.4 0.990 0.803 7 gfrp 27.6 3.44 127.4 118.6 75.4 0.931 0.592 8 gfrp 59.8 3.68 143.4 150.2 89.5 1.047 0.624 9 gfrp 56.3 5.58 169.8 164.6 102.8 0.969 0.605 10 gfrp 55.2 4.43 85.1 92.3 55.7 1.085 0.655 11 gfrp 39.6 3.38 134.9 140.5 82.2 1.042 0.609 12 bfrp 61.7 3.23 200.0 209.8 164.1 1.049 0.821 13 cfrp 40.1 1.76 170.5 162.7 162.0 0.954 0.950 14 cfrp 40.4 2.52 178.7 180.0 158.2 1.007 0.885 15 gfrp 39.3 3.36 162.3 161.9 127.4 0.998 0.785 16 gfrp 32.5 1.19 185.5 187.3 211.7 1.010 1.141 17 gfrp 41.4 1.28 154.1 134.9 77.9 0.875 0.506 18 gfrp 41.4 1.71 106.4 100.9 55.4 0.948 0.521 19 gfrp 29.8 1.67 80.0 76.0 70.0 0.950 0.875 20 gfrp 29.8 6.26 118.0 110.0 117.8 0.932 0.998 21 cfrp 29.8 0.76 76.0 74.0 63.8 0.974 0.839 22 cfrp 29.8 1.14 105.0 100.0 100.5 0.952 0.957 23 cfrp 29.8 1.81 125.0 123.0 117.2 0.984 0.938 24 gfrp 40.6 1.09 76.0 80.0 79.7 1.053 1.048 25 gfrp 40.0 5.74 112.0 118.0 138.4 1.054 1.236 26 cfrp 47.0 0.67 70.0 75.0 75.5 1.071 1.079 27 cfrp 44.7 1.34 100.0 101.0 124.4 1.010 1.244 28 cfrp 44.0 3.18 120.0 125.0 145.1 1.042 1.209 29 gfrp 30.0 3.61 123.2 127.8 129.1 1.037 1.048 30 cfrp 30.0 3.13 135.0 139.9 132.3 1.036 0.980 31 gfrp 48.0 4.89 135.0 130.7 104.3 0.968 0.773 32 gfrp 48.0 4.80 138.6 134.6 119.9 0.971 0.865 33 cfrp 48.0 4.25 155.0 144.8 107.3 0.934 0.692 34 gfrp 24.0 1.21 92.8 99.0 79.6 1.067 0.858 35 gfrp 24.0 1.82 125.6 132.1 93.2 1.052 0.742 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 22 36 gfrp 29.3 1.06 207.0 209.5 137.1 1.012 0.662 37 gfrp 29.3 2.28 307.0 302.7 192.6 0.986 0.627 38 gfrp 29.9 2.44 229.7 228.0 162.7 0.993 0.708 39 gfrp 36.5 2.12 227.0 228.0 177.4 1.004 0.781 40 gfrp 29.9 5.12 331.3 332.8 230.9 1.005 0.697 average 1.001 0.844 standard deviation 0.007 0.032 table (4) statistical comparison norm proposed neural model (nn1) aci approach mean absolute error (mae) 4.4 31.4 root mean squared error (rmse) 5.7 41.7 mean absolute percentage error (mape) 3.6 21.7 fraction of variance (fov) 0.992 0.582 connection weightsnodes hidden layer output layer input layer input signal output signal figure (1) architecture of a neural network al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 23 figure (2) artificial neuron model figure (3) four point loading beam figure (4) proposed neural model topology (m=a/l) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 24 figure (5) regression analysis for training group figure (6) regression analysis for testing group al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 25 figure (7) comparison between predicted and actual loads 10-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 investigation of thermosyphon loop performance in double-cycle distillation heat pump system mohammed a. hussien assistant lecturer automobile department-najaf technical college abstract the performance of a thermosyphon loop in a double cycle distillation heat pump system, utilizing water as a working fluid and finned tube heat exchangers for evaporator and condenser, has been investigated. a mathematical model is set for the whole system and a simulating program is developed to simulate the double cycle processes during the steady state operation. a complete steam tables subroutine developed and incorporated with the main program to calculate the water and steam properties in the range of (60 120)o c and (0.199 1.985)bar. the experimental results show good agreement with the results obtained from the computer program (quick basic). during steady state operation of the system, it found that the thermosyphon loop performance (loop conductance) increase when the working mass flow rate increase and also it increase when the working fluid pressure increase and has a maximum value (493.022 w/m2. k) at working mass flow rate of 5.5 kg/hr, working fluid pressure of 0.8 bar and process fluid pressure of 1.01825 bar. keywords: thermosyphon loop, double-cycle, distillation, heat pump, performance الدورة الخالصة . . . )60 120(o)0.199 1.985 ( . . ، ) ( )493.022(/٢. .)1.01825()0.8(، ساعة/)5.5( al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 nomenclature symbol description units ab bare tube outside surface area m2 af fin surface area m2 ai,o wall element outside area m2 ao condenser outer surface m2 cp specific heat of constant pressure kj/(kg.k) csf is an experimental constant yunis, a.c. & micheal, a.b.[12] cv specific heat of constant volume kj/(kg.k) dh hydraulic diameter m g gravity acceleration m/s2 h enthalpy kj/kg h1p heat transfer coefficient of single-phase w/m2.k h2p heat transfer coefficient of two-phase w/m2.k hamb heat transfer coefficient of ambient temperature w hhe height m ho convection heat transfer for outer fluid w/m2 hpf heat transfer coefficient of process fluid w/m2 ifg latent heat of vaporization j/kg kf thermal conductivity w/m.k lft length of fin m li distance along the evaporator or condenser from the entrance. m prl liquid prandtl number psat. saturation pressure bar pw pressure bar q heat flux w/m2 qc heat rejected by condenser w qi heat transferred working fluid to wall element i w re reynolds number. rpf thermal resistance of process fluid side w/m2 rw wall thermal resistance w/m2 rwf thermal resistance of working fluid side w/m2 s entropy kj/kg s parameter defined in eq. (36) tamb ambient temperature co tf fin thickness m al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 tpf temperature of process fluid co tsat. saturation temperature co tw,in inside wall temperature co tw,o outside wall temperature co twf temperature of working fluid co u overall heat transfer coefficient w/m.k uloop loop conductance w/m.c o wft width of fin m whe width of heat exchanger m x quality pf ratio of the total heat transfer area to the total volume of the heat exchanger m -1 pf ratio of fin surface area to the total outside area pfrc.,1p pressure difference due friction bar f fin efficiency tot total fin efficiency inclination angle of the system pipes from horizontal degree ρ density kg/m3 l liquid density kg/m3 vapour density kg/m3 σ surface tension n/m v specific volume m3/kg μ dynamic viscosity n.s/m2 μl dynamic viscosity of liquid n.s/m2 1. introduction thermosyphon are devices heated at locations below the points of cooling so that mass and heat transfer around the loop is transported through natural convection processes. in the presence of gravity, buoyancy forces due to thermal expansion of a working fluid guide the flow. thus a circulation is created which transfers energy by convection from the heated section of the loop to the cooled one. the toroidal thermosyphon consists of a closed loop of tubing in the form of tours. the tube is filled with a fluid and heated over a part of its length and cooled over the other part. the steady and time dependent behavior of closed natural circulation loops is important for several engineering applications. for instance, in solar thermosyphon hot water heaters, the heat transfer fluid is heated at the solar collector and rises through a pipe to an elevated storage tank. here, it transfers heat to the water in the tank, and consequently falls back down to the collector. natural circulation may also arise in the emergency cooling of nuclear reactor cores, e.g., when a pump failure occurs. other applications include cooling of internal combustion engines and turbine blades, geothermal power production, thermosyphon rebuilders, heat exchanger fins, permafrost protection, ice production, computer cooling, green houses, arctic and climate applications. (sh. h. shams el-din). al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 desalination desalination is employed when: 1 there is a need for purification and reuse of water. 2 when long distance transport of fresh water is not feasible. 3 in arid and semi arid areas, or when there is a source of saline water. 4 a direct or indirect source of energy is available. desalination describes a range of processes which are used to reduce the amount of dissolved solids in water. as a means of producing potable water, desalination is usually an expensive option. it is often associated with electricity generation plants, from which both electricity and waste heat are available (smith, m. and shaw, r). desalination processes are classified according to the salt separation phenomenon involved in the process, as follows: 1 processes utilizing membranes and ion selective properties in these processes, desalination is realized by using selective membranes, as in (reverse osmosis, electrodialysis, ion exchange and solvent extraction). 2 processes employing the phase change of water in these processes, desalination occurs by (crystallization separation or distillation). desalination by distillation distillation is the oldest and most commonly used method of desalination. the world's first land-based desalination plant, a multiple-effect distillation (med) process plant that had a capacity of 60 m3/day, was installed on curaçao, netherlands antilles, in 1928. further commercial development of land-based seawater distillation units took place in the late 1950s, and initially relied on the technology developed for industrial evaporators (such as sugar concentrators) and for the shipboard distillation plants which were built during world war ii. the multistage-flash (msf), med, and vapor-compression (vc) processes have led to the widespread use of distillation to desalinate sea water (al – wakil, b.k).. technical description distillation is a phase separation method whereby saline water is heated to produce water vapor, which is then condensed to produce freshwater. the various distillation processes used to produce potable water, including msf, med, vc, and waste-heat evaporators, all generally operate on the principle of reducing the vapor pressure of water within the unit to permit boiling to occur at lower temperatures, without the use of additional heat. distillation units routinely use designs that conserve as much thermal energy as possible by interchanging the heat of condensation and heat of vaporization within the units. the major energy requirement in the distillation process thus becomes providing the heat for vaporization to the feed water. the double distillation heat pump system: the double cycle distillation system is a new method for producing potable water. one such system was presented at the committee of technology transfer conference, by the name of zyclodest plant at 2001. zyclodest plant is a special mechanical vapor compression method. in it the working fluid exists in a separate loop for the heat recovery. thus, the product vapor, process fluid, is only contact with heat exchangers and does not pass through the compressor and its rotating elements. the schematic diagram of this heat pump can be envisioned as shown in the fig. (1). according to fig (1), the thermosyphon loop performance, loop conductance (u) abdul – ghafour, g.r., as follows: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 difference etemperatur sinksource area surfaceouter condenser condensertheby rejectedratetransferheat econductancloop (1) sinksourceout c loop tta q u (2) where, tsource: is the temperature at the evaporator inlet. tsink: is the temperature at the condenser inlet. the double cycle distillation heat pump plant consists of two main cycles; the water compression expansion cycle, which called also the compression expansion vapor (cev) cycle, and the process cycle, or named the thermosyphon loop. each of these cycles is described as follows: compression-vapor cycle the compression expansion vapor cycle consists of compressor, expansion device, and two heats exchangers with interconnecting piping. one of the heat exchangers submerged in a pool boiling liquid and represents a condenser coil, which is mounted at an angle of inclination of about 15 degree with respect to the horizontal so as to allow for condensate drainage. the other heat exchanger is exposed to a collective vapor and represents an evaporator coil. the evaporator and the condenser are mounted at the same angle to simplify the construction. process cycle (thermosyphon loop) this cycle consists of three main parts with interconnecting piping, namely: evaporation chamber, intermediate (im) zone and condensation chamber. a brief description of this cycle is as follows: in the evaporation chamber (boiler), the evaporator coil submerged in a pool of water and the heat will transfer through the evaporator walls to the water in the pool. due to this heat transferred, water will boil and the amount of evaporative mass depends on the amount of heat transfer. the vapor will rise due to the difference in density to pass through the intermediate (im) zone through corrugated channelsteam rising from the tub bottom will carry the small droplets of water and get rid of them is on a path winding passage changes direction sharply, leading to the elimination of water droplets and the accompanying access to saturated vapor -. this part is used to avoid mist flow, and then the vapor enters the condensation chamber as a saturated vapor. in the condensation chamber, the condenser coil is exposed to the saturated vapor. due to the heat transferred to the working fluid inside the condenser through the walls of the condenser, the vapor will condensate on the outside walls of the condenser. the condensate will exit from the condensation chamber and return to the evaporation chamber by the distillate water pump, by gravity, or the pressure difference. the heat exchangers used for evaporator and condenser of the double loop distillation heat pump system are finned tube heat exchangers, as shown in fig. (3). 2. theory a mathematical model will be set for the two loops and a computational program will be developed to simulate the two loops during steady state operation for knowing the effect of the al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 working mass flow rate on the thermosyphon loop performance with different working and process fluid pressures. thus, the analysis, in this study, is concentrated for the thermosyphon loop components and the working and process fluid, as follows: 2.1 physical properties 2.1.1 working and process fluid the working and process fluids in both the cev and process loops respectively are that of pure water. the properties of pure water as required for simulation can be divided into: a. thermodynamic properties: which include ( , h, s, cp and cv), obtained from uk steam tables in si units. b. transport properties: which include ( , k, and ), obtained from (schmidt, e). all the above thermodynamic and transport properties are calculated for the different flow types using standard table correlations, in the temperature range of (70 130) oc. for saline water, the thermodynamic and transport properties are direct functions of temperature and degree of salinity and in some cases they are established based on comparison with the same properties for pure water. the essential empirical equations for these properties as a function of temperature and degree of salinity are obtained from (sh. h. shams el-din). 2.1.2 walls and insulation the properties of the system materials and insulation are assumed constant. also the thermal conductivity for insulation (glass wool), pipes (wrought iron), fins and tubes of the heat exchangers (aluminum) and system body (galvanized plates) are obtained from (ashrae handbook & holman, j.p). 2.2 heat transfer analysis: 2.2.1 modeling of evaporation chamber amodeling of condenser: referring to fig (4), the heat transfer rate from the working fluid (vapor) to the process fluid (liquid) in an element (i) in the condenser is: qi = convective heat transfer = conduction heat transfer = convective heat transfer from working fluid to the through the wall of from the wall of element the wall of element (i) element (i) (i) to the process fluid (3) pf pfow, w ow,inw, wf inw,wf r tt r tt r tt (4) pfwwf pfwf rrr tt (5) and, pfwwf o rrr 1ua (6) boutside convective thermal resistance: liquid (process fluid) side convective thermal resistance is given as (holman, j.p): al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 tot.ooi, pf ha 1r (7) outside surface area of the heat exchanger is calculated for each element length as follows: heheipfoi, dwla (8) coutside heat transfer coefficient: the heat transfer coefficient of the boiled water (process fluid) (ho), is calculated using the correlation proposed by (rohsenow), as follows: 3 lfgsf pfwl 2 1 l vl fgl pric ttcpgiq (9) so, pfw o tt qh (10) dfin analysis: the total fin efficie tot.) is calculated from the following equation (sarsam, w.s.) : surfacefinandtubefromtransferheatmaximum surfacefinandtubefromtransferheattotal tot. (11) wo,pffbpf wo,pfffpfwo,pfbpf ttaah ttahttah (12) fpf fb ffb 11 aa aa (13) f) is calculated using the following equation (holman, j.p) : f f f hm hmtanh (14) where, 2 1 ff o tk h2m (15) f) is multiplied by (2), because there are two fins protrude from the same point at the outer surface of the flat tube of the condenser, see fig. (4). econduction thermal resistance the thermal resistance due to conduction is given as (holman, j.p): ftav ft w ka tr (16) where, in o ino av a aln aaa (17) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 iftfto lwl2a (18) iftftftftin ltwtl2a (19) finside convective thermal resistance: the working fluid side convective thermal resistance is given as: inin wf ah 1r (20) since the working fluid inlet to the condenser as superheated vapor flow, therefore, the heat transfer coefficient (hin) is calculated according to the correlation proposed by (sieder and tate) , for laminar or turbulent fully developed hydrodynamic flow. for laminar flow (re < 2400), 0.14 w 3 1 i h h 1p l dprre d k1.24h (21) for turbulent flow (re > 2400), 0.14 w 4.08.0 h 1p prred k027.0h (22) when the bulk fluid temperature reaches the saturation temperature, the two phase flow (condensation) heat transfer coefficient (h2p) of an inclined condenser is calculated from the following correlation (sarsam, w.s.) : 4 1 wsat.hl fg 2 l 3 l 2p ttd ikg eh (23) where, o o 9040for 4 1 90 50 40cos0.727e 400for0.727e (24) the condensate in an actual condensation process is cooled farther to some average temperature between saturation temperature (tsat.) and wall temperature (tw), releasing more heat in the process. therefore, the actual heat transfer will be large. (rohsenow) show that the cooling of the liquid below the saturation temperature can be accounted by replacing (ifg) by the modified latent heat of condensation (ifg*), which defined as follows (yunus, a.c. and michael, a.b.) : for saturated vapor at the condenser inside, wsat.lfgfg ttcp0.68ii (25) for superheated vapor at the condenser inside, sat.vvwsat.lfgfg ttcpttcp0.68ii (26) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 2.2.2 modeling of interconnecting piping: the same equations used for condenser to calculate the inside convective thermal resistance, conduction thermal resistance of the pipes walls and also the inside heat transfer coefficient for vapor and liquid region are used. the outside heat transfer coefficient is calculated by equations of natural convection in air depending on the angle of incline of the line with the horizontal sarsam, w.s. , as follows: 1 for angle of inclination equals to zero. 3 1 ambwfamb tt1.24h (27) 2 for angle of inclination more than zero. 3 1 ambwfamb tt1.31h (28) 2.2.3 modeling of intermediate zone: the inside convective and conduction thermal resistances and also the inside heat transfer coefficient for single phase flow (vapor) are calculated using the same equations which used in the process of modeling of the condenser. the outside heat transfer coefficient (hamb.) is calculated using the equations which used in the process of modeling of interconnecting piping. 2.2.4 modeling of expansion – device the process fluid (vapor) will expands when it passes through the expansion device. the expansion process occurs at constant enthalpy (i = c). 2.2.4 modeling of condensation chamber the evaporator is mounted in a pool of the process fluid (vapor). due to the heat transfer, the temperature of the vapor will decrease until the vapor condenses at the outside surface of the evaporator walls. thus, the same equations used for condenser are used for the evaporator, with the following differences. aoutside heat transfer coefficient the outside condensation heat transfer coefficient is calculated by the following correlation (sh. h. shams el-din.) : for rel < 1800 4 1 wvhl fg 3 lvll o ttd ikg 0.725h (29) for rel > 1800 4 1 wvhl fg 3 lvll o ttd ikg b0.725h (30) where, 2nr0.00157035nr0.03538081.23795b (31) nr: is the number of tube rows of the heat exchanger. binside heat transfer coefficient: the working fluid inlet to the evaporator as two phase flow, therefore, the two phase heat transfer coefficient is calculated according to the correlation proposed by (chen), as follows: h2p = hcon. + hb (32) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 f d kprdx1g0.023h ll 0.8 l con. (33) spptt i cpk0.00122h 0.75sat.w 0.24 sat.w0.24 v 0.24 fg 0.29 l 0.5 0.49 l 0.45 l 0.79 l b (34) where, 0 .1 x 1when0 .2 1 3 x 12 .3 5f 0 .1 x 1when1f tt, 0 .7 3 6 tt, tt, (35) 70refor1s 70re32.5forre0.421s 32.5reforre0.121s 2p 2p 10.78 2p 2p 11.14 2p (36) 0.1 l v 0.5 v l 0.9 tt, x1 x x 1 (37) 41.25 l 2p 10f dx1gre (38) the heat transfer coefficient outside the condensation chamber (hamb.) is calculated using the same equations which are used in the process of modeling of interconnecting piping. 2.3 hydrodynamic analysis process fluid – side for single phase flow, the frictional pressure drop is calculated from the following relation (franzini, j.b. and fennimore): 2 g d l4 2 h i frc,1p f (39) where, for single phase laminar flow re 16f (40) and, for single phase turbulent flow 0.25re 0.079f (41) the hydrostatic pressure drop for the process fluid is calculated from, (al – wakil, b.k.): sinlgh (42) where, process fluid. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 system pipe. minor losses occurring due to the inlet and exit to the pipes and the existence of fitting, (franzini) and (finnemore0, for the loss factor (fl). the following relation is used for the pressure losses: 2 gf 2 l minor (43) 3. description of the experiment this study is directed towards the investigation of the thermosyphon loop performance (loop conductance), as a process cycle, in double cycle distillation heat pump system with varying the distillation conditions. 4. experimental setup the double cycle distillation heat pump system for desalination, utilizing water as the working and process fluid, is designed and constructed in accordance with the schematic diagram in fig. (5). the two loops of the heat pump are a sealed system charged with a known mass of working and process fluid and work under different pressures. the two loops are insulated in order to minimize heat flow to ambient. a pictorial view of the test rig is shown in fig. (6). experimental program was initiated to studying the influence of mass flow rate of the cev loop on the thermosyphon loop performance, uloop, with different working and process pressures. the evacuating and charging the system are attained using two different points for cev loop and four different points for thermosyphon loop, and a fifth point at the bottom of the liquid line is used to specify the level of the feed water in the evaporation chamber. the heat exchangers used for the evaporator and condenser has an outside surface area of about (0.325 m2). the evaporation and condensation chambers are constructed with a shape coincide with the size and configuration of the condenser and the evaporator coils respectively. the (i.m) zone is constructed from three inclined channels in the space between the evaporation and the condensation chambers. a (600) watt water heater is installed in the evaporation chamber. this heater is used as start heating to reach the raw water to the boiling degree at the beginning of the operation. the liquid (distillated water) and vapor lines are constructed from 1/2 and 3/4 inch galvanized (wrought iron) pipes respectively. 3/4 inch gate valve is used as expansion device. distillated water is used as the working fluid in cev loop since its a cheep, good and available working fluid. its also used as process fluid in thermosyphon loop to facility the loop performance investigation. 5. instrumentation and calibration 5. 1. temperature measurement thermally sensitive resistors (thermistors) are used to measure the working and process fluid temperatures in all parts of the test rig. the thermistors are connected to a selector switch. the selector switch is connected to a digital multi-meter (hp 3435a) with a sensitivity of 0.1 calibration of thermistor is carried out with temperature range of (70 115) oc. 5. 2. pressure measurement a pressure gages (vacuum pressure gage the two another from (1-3) bar), bourdon type, are calibrated and used to measure the pressure of working and process fluid at different points of the system. 5. 3. water flow rate measurement an orifice -0.6dplate is calibrated and used to measure the volumetric flow rate of water inside the compression expansion vapor loop. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 6. leak tests before starting up the test runs for the system, the leak tests are carried out for the two loops of the system 7. system insulation in order to minimize the heat transfer with the surrounding, a glass wool sheets, with different thickness (1, 1.5, 2) cm, insulation covered by an aluminum foil are used to cover the all parts of the two loops of the system, as shown in fig. (6). 8. results and discussion the performance of the thermosyphon loop working with different mass flow rate is defined as a loop conductance (uloop), as follows: 42 c sinksourceout c loop tt q tta q u (44) where, inoutc ii . mq (45) iin: is the enthalpy at the condenser inlet. iout: is the enthalpy at the condenser outlet. the effect of working mass flow rate on the thermosyphon loop performance for different process fluid pressure is shown in fig (7) to fig(9) at different working fluid pressure. for all figures, we can be observed that the loop performance (loop conductance) increases when the working mass flow rate increase, for all process fluid pressure except the pressure of 1.02825 bar at working fluid pressure of 0.7 bar. this behavior can be explained by; increasing the working mass flow rate lead to increasing the heat transfer by the condenser, therefore, the loop conductance is increased. from fig (7), and referring to the general trend on the behavior of the loop conductance with the working mass flow rate for low working fluid pressure, i.e. at working fluid pressure of 0.7 bars, it is shown that for process fluid of 1.01825 and 1.02325 bars, the loop conductance increased when the mass flow rate increased. this explained by the fact that when the working mass flow rate increased the liquid vapor column in the condenser will be increased. so that, the effective condenser heat transfer surface area is increased as well. thus, the heat rejected by the condenser is increased and causes the loop conductance increasing. the above behavior of the loop conductance with the working mass flow rate is occurred for working fluid pressure of 0.75 and 0.8 bar for any process fluid pressure, as shown in fig.(8) and fig.(9) respectively. now, returning to fig.(7), and for process fluid pressure of 1.02825 bar, it is observed that increasing the working mass flow rate will increase loop conductance up to the point in which the curve reaches zero slop, i.e. maximum loop conductance, and then starts to decrease. this can be explained by; the fact that increasing the process fluid pressure will increase the outer heat transfer coefficient and then the heat rejected by the condenser is decreased although the liquid vapor column is increased, but increasing the liquid vapor column is wane with the process fluid pressure increasing. in addition the heat transfer decrease, the high source temperature, which occur at low working fluid pressure, i.e. at 0.7 bar, and reaches to about 109.36 oc, also lead to decrease the loop conductance. 9. conclusions 1. a computational program was developed for simulating the steady state operation of a double cycle distillation heat pump system. the computed results were in good agreement with the experimental data obtained from the test rig, for the thermosyphon loop performance. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 2. from the experimental results, it was concluded that the water represents an efficient working fluid and can provide reasonably accurate results for the double cycle distillation heat pump system. in addition it is cheap and available. 3. any increase in the working mass flow rate, for working fluid pressure of 0.75 and 0.8 bars even for 0.7 bar at process fluid pressure of 1.01825 and 1.02325 bar, will clearly increase the thermosyphon loop conductance. 4. the thermosyphon loop conductance, for working fluid pressure of 0.7 bars at process fluid pressure of 1.02825 bar, increases with increasing the working mass flow rate until it reach the maximum points and then starts to decrease. 5. the maximum loop conductance was seen to occur at a working mass flow rate of 5.5 kg/hr, working fluid pressure of 0.8 bars and process fluid pressure of 1.01825 bars. acknowledgement the experimental rig which built by (h. gh. al – hussaini), was used as a working test rig on which predictions of results are made. references: abdul ghafour, g.r. "thermosyphon loop performance with multiple pipe evaporator", m.sc. thesis, university of baghdad, 1996. al wakil, b.k. "parametric study of the two phase thermosyphone system", m.sc. thesis, university of baghdad, 1998. ashrae handbook "fundamentals volume", new york, 2009. chen, j.c. "correlation for boiling heat transfer to saturated fluids in convective flow", inst. eng. chem. process design and development, vol. 5, no. 3, pp. 322 329, 1966. committee of technology "zyclodest distillation plant" germany, 2001. franzini, j.b. and finnemore, e.j. "fluid mechanics with engineering applications", mcgraw hill book company, 10th edition, 2002. holman, j.p. "heat transfer", mcgraw hill book company, 1989. rohsenow, w.m. "a method of correlating heat transfer data for surface boiling of liquids", trans. asme, vol. 74, pp. 969 976, 1952. sarsam, w.s. "the performance of thermosyphon system as a heat regenerator", m.sc. thesis, university of baghdad, 1995. schmidt, e. "properties of water and steam in si units", new york, 1981. sh. h. shams el-din. " heat transfer characteristics of an inclined single-phase toroidal thermosyphon", alexandria engineering journal, vol. 44 (2005), no. 2, 157-171. sieder, e.n. and tate, j.e. "heat transfer and pressure drop of liquids in tubes", ind. and eng. chem., vol. 28, no. 12, pp. 1429 1434, 1936. smith, m. and shaw, r. "desalination by reverse osmosis and distillation", wedc loughborough university, 2002. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 uk steam tables in si units, london: edward arnold (publishers) ltd., 1970. yunus, a.c. and michael, a.b. "thermodynamic an engineering approach", mcgrow hill book company, 2006. fig. (1): schematic diagram of hypothetical twine cycle heat pump. storage tank cycle i : is the compression expansion vapor cycle cycle ii : is the process cycle q condenser evaporator q h q l evaporation chamber condensation chamber gases start heating w at er pu m p w2 c om pr es s w1 cycle i cycleii 1 2 3 4 5 6 7 8 9 e xp an si on l vapor flow liquid flow liquid vapor flow i.m .z on e al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. (2): schematic representative diagram of the double cycle distillation heat pump plant. fig. (3): schematic diagram of the finned tube heat exchanger used in this work for evaporator and condenser coils. fig. (4): overall heat transfer through an evaporator element (a) sketch ; (b) thermal resistance net work. evaporation chamber liquid vapor flow liquid flow vapor flow expansion valve condensation chamber evaporator compressor condenser heating source im zone rpfrwrwf qi twf tw, in tw, o tpf working fluid process fluid twf, t+1 tw, o i twf, i tw, in i+1 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. (5): p. i. diagram of the test rig. fig. (6): pictorial view of the test rig t p t t t t t t evaporator condenser evaporation chamber condensation chamber motor compressor p t t p orifice flow meter t p t p t p t p pp p p t t p al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 180 200 220 240 260 280 300 2.5 3 3.5 4 4.5 5 5.5 working mass flow rate (kg/hr) t he rm os yp ho n l oo p c on du ct an ce (w /m k ) p pf=1.01825 bar comp. p pf=1.02325 bar comp. p pf=1.02825 bar comp. p pf=1.01825 bar exp. p pf=1.02325 bar exp. p pf=1.02825 bar exp. fig. (7): effect of working mass flow rate on the performance of the thermosyphon loop for different process fluid pressure at working fluid pressure of 0.7 bars. 235 260 285 310 335 360 2.5 3 3.5 4 4.5 5 5.5 working mass flow rate (kg/hr) t he rm os yp ho n l oo p c on du ct an ce (w /m k ) p pf=1.01825 bar comp. p pf=1.02325 bar comp. p pf=1.02825 barcomp. p pf=1.01825 bar exp. p pf=1.02325 bar exp. p pf=1.02825 bar exp. fig. (8): effect of working mass flow rate on the performance of the thermosyphon loop for different process fluid pressure at working fluid pressure of 0.75 bars. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 250 275 300 325 350 375 400 425 450 475 500 2.5 3 3.5 4 4.5 5 5.5 working mass flow rate (kg/hr) t he rm os yp ho n l oo p c on du ct an ce (w /m k ) p pf=1.01825 bar comp. p pf=1.02325 bar comp. p pf=1.02825 bar comp. p pf=1.01825 bar exp. p pf=1.02325 bar exp. p pf=1.02825 bar exp. fig. (9): effect of working mass flow rate on the performance of the thermosyphon loop for different process fluid pressure at working fluid pressure of 0.8 bars. 3 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٤٤ use of combined nondestructive test methods to predict concrete compressive strength cast with aggregate obtained from southern parts of iraq ass. prof. sallal r. a. al-owaisy, prof. ghazi f. kheder, and ass. lect. ahmed a. abbas wasit university , mustanseriyah university, shatra technical institute abstract concrete compressive strength is one of the most important concrete requirements that can be used to decide if the concrete is structurally acceptable or not. in several cases there is a need to estimate the concrete compressive strength on the site during construction or later on during the life of concrete. there are several methods used for this purpose, among the mostly used methods are the ultra sonic pulse velocity and the schmidt hammer rebound number. in this work six different fine aggregate and two different coarse aggregate were obtained from different parts of southern iraq. using these different aggregate combinations, 120 different concrete mixes with mix proportions of 1:2:4 or 1:1.5:3 and w/c ratios ranging between 0.40 to 0.60 were cast into 152 mm cubes. the compressive strength, ultrasonic pulse velocity, schmidt hammer’s rebound number and concrete density were measured. these results were introduced into nonlinear multiple variable regressions to obtain correlation relationships to predict the concrete compressive strength. two groups of regressions were formulated, the first used only the ultrasonic pulse velocity and rebound number in the regressions, and separate regressions were prepared for each single source of aggregate. the results of the predicted strength was in good agreement with the experimentally measured values, the value of the standard errors of these regressions were less than 10% of the lowest concrete strength investigated (20mpa). in the second group of regressions, the data from all concrete mixes with different aggregate sources were combined together to obtain the correlation regressions. these regressions were formulated because in many cases in practice the source of aggregate may not be known exactly. two subgroups were developed, with different independent variables combinations. the standard error of this group was higher than for the first group, its best value was 16% of the minimum value of concrete strength investigated. this clearly proves the importance of the aggregate source on the predicted concrete compressive strength values. key words: nondestructive test, ultrasound pulse velocity, rebound number, combined ndt test, strength evaluation, concrete compressive strength. لخرسانة مصنعة من ركام االنضغاططرق الفحص االإتالفي المشترك لتقییم مقاومة استخدام من المنطقة الجنوبیة للعراق غازي فیصل خضر. م.م، أحمد عبدالهادي عباس. د. أ،صالل راشد عبد العویسي. م.أ الشطرة/هد الفنيالمع، المستنصریةجامعة ال، جامعة واسط al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٤٥ :الخالصة .و الدیمومةالخرسانة أحد أهم الخواص الالزمة لتحدید مدى قبولیة الخرسانة من الناحیة اإلنشائیةانضغاطتعتبر مقاومة . االنجازالخرسانة في الموقع سواًء أثناء التنفیذ أو خالل عمر المنشأ بعد انضغاطحاجة لتقییم مقاومة ظهر في عدة حاالت ت سرعة األمواج فوق الصوتیة ورقم هي قییم مقاومة انضغاط الخرسانة و من أكثر هذه الطرق شیوعًا تلالأتالفیة عدة طرق ستخدم ت في هذا البحث تم استخدام ستة أنواع مختلفة من الركام الناعم ونوعین من الركام الخشن من مصادر طبیعیة .مطرقة شمیتارتداد خلطة خرسانیة مختلفة بنسب ١٢٠استخدمت هذه األنواع المختلفة من الركام في أعداد . من العراقمختلفة من المنطقة الجنوبیة مم ١٥٢استخدمت مكعبات قیاسیة بأبعاد . ٠.٦إلى ٠.٤سمنت تتراوح من /وبنسب ماء) ١:١.٥:٣(أو ) ١:٢:٤(خلط وزنیة طرقة شمیت وكثافة الخرسانة على هذه النماذج ثم بعد ذلك تم قیاس سرعة األمواج فوق الصوتیة ورقم ارتداد م. كنماذج للفحص استخدامت نتائج هذه الفحوصات في إجراء تحلیل الخطي متعدد المتغیرات إلیجاد . تم قیاس مقاومة أنضغاطها أتالفیا لحین الفشل في ، وعتین من عملیات التحلیلتم صیاغة مجم.عالقات ارتباط لتخمین مقاومة انضغاط الخرسانة بأستخدام الفحوصات الالأتالفیة أجریت . المجموعة األولى استخدم سرعة األمواج فوق الصوتیة ورقم ارتداد مطرقة شمیت فقط لتحدید مقاومة أنضغاط الخرسانة طأ عملیات التحلیل لكل نوع من أنواع الركام وكانت القیم المستنبطة لمقاومة انضغاط الخرسانة مقاربة للنتائج العملیة وبنسبة خ أما في المجموعة الثانیة من عملیات التحلیل فقد تم . من أقل قیمة مسجلة لمقاومة انضغاط الخرسانة% ١٠قیاسي التتجاوز أعتماد نتائج كافة الفحوصات و لجمیع الخلطات بغض النظر عن نوع الركام والسبب في ذلك أن مصدر الركام في كثیر من أعطت نتائج المجموعة الثانیة نسبة خطأ أعلى من المجموعة األولى حیث . رسانة المنشأاالحیان قد یكون مجهوًال عند تقییم خ هذه النتیجة تثبیت أن تحدید نوع و مصدر الركام . من أقل قیمة مسجلة لمقاومة االنضغاط% ١٦كانت أفضل قیمها تساوي .خرسانةالمستخدم في الخلطة الخرسانیة عامل مهم في عملیة تحمین مقاومة انضغاط ال introduction it is often necessary to test concrete structures after the concrete has hardened to determine whether the structure is suitable for its designed use. ideally such testing should be done without damaging the concrete. the tests available for testing hardened concrete range between the completely nondestructive, where there is no damage to the concrete, through those were the concrete surface is slightly damaged, to partially destructive tests, where the concrete surface had to be repaired after testing. the range of properties that can be assessed using nondestructive tests is quite large and includes such fundamental parameter as density, elastic modulus, compressive strength, surface hardness and absorption as well as reinforcement size and location. concrete compressive strength is one concrete property that is widely needed to be evaluated during the progress of concrete structures execution. among the most used nondestructive test methods in assessing concrete compressive strength are the ultrasonic pulse velocity and the schmidt hammer rebound number. these two methods are known for more than 50 years [(carino ,1994) (bungey and millard ,1996)]. the first method is used to measure the sound velocity in concrete and concrete compressive strength, while the second method evaluates concrete compressive strength through measuring its surface hardness. these two methods have been known for more than 50 years and gained wide spread use worldwide for their low cost and simple and fast test procedures. numerous reports and researches have been published on these two methods aiming to obtain mathematical formulations to be used to determine the concrete compressive strength. from previous literature it can be recognized that there is no unique mathematical relationship that can be used worldwide for this purpose. this is because the readings and results of these two methods are largely affected by many factors; among these factors are the elastic properties of aggregate (aggregate source) and their proportion in the concrete, concrete density and moisture content. thus al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٤٦ large number of mathematical relationships was obtained aiming to give good assessment to concrete compressive strength [(iaea ,2002)( aci committtee 228.1r-95)]. in this research work, it was aimed to obtain mathematical relationships that can be used for the assessment of compressive strength of concrete cast using fine and coarse aggregate obtained from different sources in the southern parts of iraq. six different fine aggregate and two coarse aggregate sources were investigated. in addition, two nominal concrete mix proportions with different water / cement ratios were also included as a variable in this research. these two nominal mixes are commonly used in the southern part of iraq. experimental work two well known nondestructive test methods were used in this work, these methods are the ultrasonic pulse velocity and the schmidt hammer. the readings and the accuracy of these two methods are very much affected by the elastic properties and proportions of aggregate in the concrete mix. in order to obtain a clear image on the effects of these factors on the accuracy of predicting concrete compressive strength using combined nondestructive test methods, several types of coarse and fine aggregates, from different sources in southern parts of iraq were used. testing program the testing program was planned to obtain information about the effect of mix proportions (aggregate to cement and water to cement ratios) and type of coarse and fine aggregates and concrete density on the results of the upv and rn methods and on their accuracy in predicting concrete compressive. two nominal concrete mixes 1:2:4 and 1:1.5:3 mixes with w/c ratio in the range of 0.40 to 0.60 were investigated. these mixes were chosen to represent those widely used in iraqi construction projects. also two natural types of coarse aggregate and six types of fine aggregate obtained from different sources in southern part of iraq was used in the preparation of the concrete mixes. the details of the materials used are given below: cement (c) two types of cement, ordinary and sulphate resisting portland cements conforming to iraqi standard iqs 5 [6] was used in this work. fine aggregate (fa) six fine aggregate types conforming to iraqi standard iqs 45 [7] were used. the sources of these aggregate and notation are given in the table 1. coarse aggregate (ca) two coarse aggregate types conforming to iraqi standard iqs 45[7] were used. table 1 also shows the source and notation of these aggregate. concrete mixes as detailed in table 2, hundred and twenty different concrete mixes with aggregate from different sources were investigated; the general characteristics of the mixes are given below: 1. mix proportions 1:2:4 or 1:1.5:3 2. nominal water/cement ratio (w/c) from 0.4 to 0.6 (the effective w/c ratio depended finally on the natural moisture condition of the aggregate and ranged between 0.444 to 0.628) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٤٧ casting and curing of test specimens 152x152x152 mm concrete cubes were prepared and cast to measure concrete compressive strength; six cubes of each mix were cast in steel moulds then covered for 24 hours by polyethylene sheets for 24 hour. the cubes were then stored in curing tanks for a total period of 28 days. after the 28 days of curing the cube specimens were removed out of water and tested immediately. testing of concrete cube specimens concrete density the densities of the concrete cubes were measured according to astm c 138-02 [9]. each value of density of each mix represents the average of densities of six cubes. values of concrete densities are given in table 3. ultrasonic pulse velocity the ultra sonic pulse velocities of the cast concrete cubes were measured according to astm c 597-02 [10]. two readings on each cube were measured (using the opposite smooth surfaces of the cube). thus each mix result of ultrasonic pulse velocity represents an average of twelve readings. table 3 gives the ultrasonic pulse velocities of all the mixes investigated. rebound number the rebound number was measured on the cube specimens using schmidt hammer and according to astm c 805-02 [11]. each cube was fixed in the compression machine, and a pressure of 7 mpa was applied on the cube. five readings were taken on each two opposite smooth surfaces of the cube, thus a total of 10 readings were taken on each cube. the final reading of rebound number of each mix was therefore the average of 60 readings. table 3 shows the values of the rebound numbers of all the concrete mixes investigated. concrete compressive strength the compressive strengths of the concrete mixes were determined using a compression machine with ultimate capacity of 3000 kn and according to iqs 248[8]. the compressive strength of each mix was the average of the compressive strength of six cubes. the results of the compressive strengths of all the 120 concrete mixes are given in table 3. experimental results table 3 shows the experimentally measured properties of all the 20 concrete mixes investigated with their ranges of actual w/c and aggregate to cement ratios. these results were fed into the statistica program in different combinations to find the constants of the multiple regressions (a0, a1, a2, a3, a4, a5). multiple non-linear regressions for prediction of concrete compressive strength in practice, it is advantageous to use more than one method of non destructive testing (ndt) at a time in predicting or monitoring concrete strength and quality. using more than one method is beneficial especially because the variations in properties and composition of concrete (aggregate type and source) largely affect the test results of the ndt. both the schmidt hammer and upv are affected by the mix proportions of the concrete, aggregate elastic properties and also by its moisture condition each in a certain manner [(astm c 805-02) (kaplan,1959)]. these factors may result in an increase or decrease in the value of the estimated concrete strength (error). such as the case of the presence of moisture in concrete: presence of moisture in concrete increases the upv, but on the al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٤٨ other hand, it decreases the rebound number recorded by the schmidt hammer (neville,2005), so when both methods are used together, the error in one method will correct the error in the second method. the presence of moisture in concrete will increase the upv reading but at the same time will decrease the rebound number, so readings of the upv and rn will correct each other and the effect of moisture will be eliminated in the estimation of concrete strength. another factor that largely affects the ndt results are the concrete mix proportions, for the same compressive strength, mixes with higher coarse aggregate will result in an increase in the upv and rebound number(bungey and millard,1996). there have been numerous attempts from different researchers throughout the world to find mathematical relationships that can predict the concrete compressive strength by using the ultra sonic pulse and the schmidt rebound hammer either separately or combined [(facacoaru ,1984) to (tanigawa and etl,1984)]. all these methods used local materials and cannot be applied for concrete cast using aggregate from other different sources. the predicted concrete strength values using the previously developed relationships will show large scatter compared to the experimentally measured values when aggregate from other sources are used in casting concrete. in order to obtain accurate relationships to predict concrete strength, multiple linear regressions were used. different forms of relationships with different combinations of independent variables can be obtained to predict the concrete compressive strength. these independent variables are: ultrasonic pulse velocity, schmidt rebound number, water/cement ratio, aggregate / cement ratio and concrete density, depending on the availability of these information on the concrete mix characteristics and aggregate origin (source). the general form of the regression is given below: fcu = ao . (upv)a1 . (rn)a2 . (a/c)a3 . (w/c)a4 . (ρ)a5 where: fcu : concrete compressive strength in mpa. upv : ultrasonic pulse velocity in km/sec. rn : rebound number. w/c : water to cement ratio by weight. a/c : aggregate to cement ratio by weight. ρ : concrete density in (kg/m3). ao, a1 to a5: regression constants. the mathematical regressions were divided into two groups. the first group considered each type of aggregate from a particular source in southern part of iraq individually, while the second group combined all the data of concrete specimens, regardless to the aggregate source, in an attempt to get more practical and easier to use regressions, and also, because in some cases, the source of aggregate may not be known. this of course will affect the accuracy of the regressions adversely, but the engineer must take this into consideration in his assessment to concrete strength. all regressions considered either ordinary portland cement or sulphate resisting portland cement. group 1: regressions for aggregates from known (particular) sources group one was divided into 20 subgroups, ten groups for each of the ordinary or sulphate resisting portland cements concrete. in each subgroup, three regressions were derived. each regression included different either the ultrasonic pulse velocity or rebound number separately or combined depending on the availability nondestructive method used in testing the concrete. in each table, the values of regression constants (ao, a1, a2,) are given. these tables also give the standard errors of estimates in the compressive strength (se) and the multiple variable correlation coefficients (r) of each regression to show its accuracy. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٤٩ table 4 gives the regressions constants for each type of aggregate source for concrete mixes cast with ordinary portland cement, while table 5 gives the constants for concrete mixes cast with sulphate resisting portland cement. each group included both 1:2:4 and 1:1.5:3 mixes. from tables 4 and 5, it can be clearly seen that the regressions gave excellent prediction, using upv test only, the value of standard error was between 0.32 to 3.41 mpa, while when using the schmidt hammer the this error was between 0.94 to 2.59 mpa. combining both nondestructive test methods, the maximum standard error value is decreased to 0.27 to 2.03 mpa. the latter value is less than 10% of the lowest concrete compressive strength investigated (20mpa). introducing the mix proportions in the regression (aggregate/cement, water/cement and density) improved the regression, but to a limited extent. therefore, using the combined upv and rn regression (with particular reference to aggregate source) was found to be sufficient and practical to predict the concrete compressive strength. group 2: regressions for aggregate from unknown source in order to extend the validity of the regressions derived for particular sources of aggregates (tables 4 and 5), other combinations of regressions were derived, in these regressions; the source of aggregate was overlooked. table 6 and 7 give regressions constants for predicting concrete strength cast with ordinary or sulphate resisting portland cements respectively, regardless to the aggregate source. it is important to highlight here that these regressions must only be used for concrete cast with aggregate from the southern parts of iraq. in these two groups of regressions (ordinary or sulphate resisting portland cements), the maximum value of standard error was 4.05 mpa when using upv method only, and 4.44 mpa when using schmidt hammer only, the value of standard error decreases to 3.52 mpa when using the combine upv and schmidt hammer test methods. when the mix properties are included, the standard error value was further decreased to 3.36 mpa. the four values of standard errors for these regressions give errors of about 20%, 22%, 19% and 17% respectively. figure 1 and figure 2 shows the observed versus predicted compressive strength for the first regression of the two groups (regressions n1 and s1). it is important to mention here that the age of concrete was not included in the regressions, because it is more preferable to depend only on the result of the upv and rebound number in addition to the mix proportions if available to represent the condition of concrete hardened properties, in many practical site cases the age of concrete may not be known exactly. limitations of the developed regressions in order to obtain a realistic predicted value for the concrete compressive strength, the general ranges of the independent variables introduced in the derivation of these regressions must be taken into consideration. these final ranges are given in table 8. conclusions on the basis of the experimental results obtained in this work, using two different nondestructive test methods for predicting concrete compressive strength, cast with aggregate obtained from different sources in the southern part of iraq, following conclusions can be withdrawn: 1. changing the source of aggregate affects the results of the ultra sonic pulse velocity and the rebound number of the schmidt hammer. there is no generalized formula that can be used al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٠ for predicting concrete compressive strength using nondestructive testing. the stiffness of aggregate largely affects the readings of the upv and rn methods. 2. the combined usage of upv and rn methods improves the predicted values of concrete compressive strength, several factors that causes variations in the readings of these methods eliminate each other, thus resulting in more accurate predicted values of concrete strength. further introducing information on concrete mix proportions and density into the mathematical regressions can improve the accuracy of the predicted value. 3. several regressions were derived for each type of aggregate source used in the concrete mix. these regressions gave excellent accuracies especially when both upv and rn methods were used together. in most cases, the standard error of the regression was less than 10 % compared with the minimum concrete strength investigated (20 mpa). it was found that there is no need to introduce the mix proportions in this case, since the regressions gave good and acceptable accuracy. 4. the accuracy of the regressions decreased when all the data from the different aggregate sources were used, due to the variation in the elastic properties of the concrete. the standard error maximum values exceeded 20% when using upv or rn methods separately. this error decreased to less than 19% when using the combined tests together. a further decrease in the standard error was obtained when the mix proportions and concrete density was introduced into the regressions, the maximum value of the standard error became less than 17%. 5. in using the derived regression, the engineer must be aware not to tolerate the limits of the independent variables used in the regression. this may result in nonrealistic predicted values. aknowledgement the authors would like to thank the iraqi ministry of higher education and scientific researches for providing the fund to carry out the work reported in this paper. thanks are also to the staff of the structural and material laboratory of shatra technical institute for providing the technical support for this work. references carino, n.j., “nondestructive testing of concrete: history and challenges”, sp 144-30 (american concrete institute, detroit 1994) pp.623-678. kolek, j., “nondestructive testing of concrete by hardness methods”, symposium on nondestructive testing of concrete and timber, (the institution of civil engineers, (london, 1970) pp.19-22. bungey, j.h. and millard, s.g., “testing of concrete in structures”, third edition, united kingdom, glasgow, 1996, 350 pp. iaea: international atomic energy agency, “guidebook on nondestructive testing of concrete structures”, vienna, 2002, pp.62-66. aci committtee 228.1r-95, “in-place methods to estimate concrete strength”, (american concrete institute, detroite, 1995). iqs 5/1984, ''portland cement,'' iraqi organization for standards and specifications. baghdad, iraq, 1984. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥١ iqs 45/1984 "aggregate from natural sources for concrete," iraqi organization for standards and specifications. baghdad, iraq, 1984. iqs 248 "method for determination of compressive strength of concrete cubes," iraqi organization for standards and specifications. baghdad, iraq, 1992. astm c 138-02, "test for unit weight, yield, and air content (gravimetric) of concrete", astm international. american society of testing materials, usa. astm c 597-02, “standard test method for pulse velocity through concrete”, astm international. american society of testing materials, usa. astm c 805-02, “standard test method for rebound number of hardened concrete”, astm international, american society of testing materials, usa. kaplan, m.f., “the effect of age and water/cement ratio upon the relationship between ultrasonic pulse velocity and compressive strength”, mag. of concrete researches, vol. 11, no. 32, july 1959, pp. 85-91. bullock, r.e. and whitehurst, e.a., “effect of certain variables on pulse velocities through concrete”, highway researches board, bull., 206, 37, 1959. neville, a.m., “properties of concrete”, fourth and final edition, united kingdom, 2005. facacoaru, i. , “romanian achievements in nondestructive strength testing of concrete”, in-situ nondestructive testing of concrete, sp-82, (american concrete institute, detroite, 1984), pp.33-56. knaze, p. and beno, p., “the use of combined nondestructive testing methods to determine the compressive strength of concrete”, materials and structures, vol. 17-no. 99, may-june 1984, (rilem, paris, 1984), pp.207-210. kehder, g.f. , “a two stages procedure for assessment of in-situ concrete compressive strength using combind nondestructive testing”, materials and structures, vol. 32, july 1999, (rilem, paris, 1984), pp.410-417. sturrup, v.r., vecchio, f.j. and caratin, h., “pulse velocity as a measure of concrete compressive strength”, in-situ nondestructive testing of concrete, sp-82, (american concrete institute, detroite, 1984), pp.201-227. swamy, n.r. and al-hamed, a.h., “the use of pulse velocity measurements to estimate strength of air-dried cubes and hence in-situ strength of concrete”, malhotra, v.m., ed., aci sp-82, (american concrete institute, farmington hills, mi, 1984), 247 pp. teodoru, g.v., “mechanical strength property of concrete at early ages as reflected by schmidt rebound number, ultrasonic pulse velocity and ultrasonic attenuation”, property of concrete at early ages, aci sp-95, (american concrete institue, detroit, 1986), pp.139-153. leshchinsky, a.m., “combined methods of determining control measures of concrete quality”, materials and structures, vol. 24, 1991, pp.177-184. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٢ tanigawa, y., baba, k. and mori, h., “estimation of concrete strength by combined nondestructive testing methods”, in-situ nondestructive testing of concrete, sp-82, (american concrete institute, detroite, 1984), pp.57-75. table 1: materials sources and notations* item cement type fine aggregate source coarse aggregate source 1 ordinary n najaf1(wilayat ali) a badrah b 2 sulphate resisting s badrah b basrah s 3 najaf2(khamas) k 4 zubair z 5 jabal sanam s 6 al ukhaider g nbs: concrete mix with ordinary portland cement, fa from badrah and ca from basrah. table 2: mix proportion details and notations mix notation mix proportion effective w/c ratio mix notation mix proportion effective w/c ratio mix notation mix proportion effective w/c ratio mix notation mix proportion effective w/c ratio nbb1 1:2:4 0.557 skb1 1:2:4 0.628 nas1 1:2:4 0.600 szs1 1:2:4 0.600 nbb2 1:2:4 0.507 skb2 1:2:4 0.578 nas2 1:2:4 0.550 szs2 1:2:4 0.550 nbb3 1:2:4 0.457 skb3 1:2:4 0.528 nas3 1:2:4 0.500 szs3 1:2:4 0.500 nbb4 1:1.5:3 0.544 skb4 1:1.5:3 0.600 nas4 1:1.5:3 0.578 szs4 1:1.5:3 0.578 nbb5 1:1.5:3 0.494 skb5 1:1.5:3 0.550 nas5 1:1.5:3 0.494 szs5 1:1.5:3 0.528 nbb6 1:1.5:3 0.444 skb6 1:1.5:3 0.500 nas6 1:1.5:3 0.444 szs6 1:1.5:3 0.478 sbb1 1:2:4 0.600 nzb1 1:2:4 0.557 sas1 1:2:4 0.557 nss1 1:2:4 0.600 sbb2 1:2:4 0.550 nzb2 1:2:4 0.507 sas2 1:2:4 0.507 nss2 1:2:4 0.550 sbb3 1:2:4 0.500 nzb3 1:2:4 0.457 sas3 1:2:4 0.457 nss3 1:2:4 0.500 sbb4 1:1.5:3 0.578 nzb4 1:1.5:3 0.544 sas4 1:1.5:3 0.544 nss4 1:1.5:3 0.578 sbb5 1:1.5:3 0.528 nzb5 1:1.5:3 0.494 sas5 1:1.5:3 0.494 nss5 1:1.5:3 0.528 sbb6 1:1.5:3 0.478 nzb6 1:1.5:3 0.444 sas6 1:1.5:3 0.444 nss6 1:1.5:3 0.473 nab1 1:2:4 0.500 szb1 1:2:4 0.600 nks1 1:2:4 0.600 sss1 1:2:4 0.557 nab2 1:2:4 0.450 szb2 1:2:4 0.550 nks2 1:2:4 0.550 sss2 1:2:4 0.550 nab3 1:2:4 0.400 szb3 1:2:4 0.500 nks3 1:2:4 0.500 sss3 1:2:4 0.457 nab4 1:1.5:3 0.550 szb4 1:1.5:3 0.600 nks4 1:1.5:3 0.578 sss4 1:1.5:3 0.544 nab5 1:1.5:3 0.500 szb5 1:1.5:3 0.550 nks5 1:1.5:3 0.528 sss5 1:1.5:3 0.494 nab6 1:1.5:3 0.450 szb6 1:1.5:3 0.500 nks6 1:1.5:3 0.478 sss6 1:1.5:3 0.444 sab1 1:2:4 0.600 nsb1 1:2:4 0.557 sks1 1:2:4 0.557 ngb1 1:2:4 0.600 sab2 1:2:4 0.550 nsb2 1:2:4 0.550 sks2 1:2:4 0.507 ngb2 1:2:4 0.550 sab3 1:2:4 0.500 nsb3 1:2:4 0.500 sks3 1:2:4 0.457 ngb3 1:2:4 0.500 sab4 1:1.5:3 0.578 nsb4 1:1.5:3 0.578 sks4 1:1.5:3 0.544 ngb4 1:1.5:3 0.578 sab5 1:1.5:3 0.528 nsb5 1:1.5:3 0.528 sks5 1:1.5:3 0.494 ngb5 1:1.5:3 0.528 sab6 1:1.5:3 0.478 nsb6 1:1.5:3 0.478 sks6 1:1.5:3 0.444 ngb6 1:1.5:3 0.478 nkb1 1:2:4 0.628 ssb1 1:2:4 0.600 nzs1 1:2:4 0.600 sgb1 1:2:4 0.600 nkb2 1:2:4 0.578 ssb2 1:2:4 0.550 nzs2 1:2:4 0.550 sgb2 1:2:4 0.550 nkb3 1:2:4 0.528 ssb3 1:2:4 0.500 nzs3 1:2:4 0.500 sgb3 1:2:4 0.528 nkb4 1:1.5:3 0.600 ssb4 1:1.5:3 0.589 nzs4 1:1.5:3 0.578 sgb4 1:1.5:3 0.578 nkb5 1:1.5:3 0.550 ssb5 1:1.5:3 0.539 nzs5 1:1.5:3 0.528 sgb5 1:1.5:3 0.528 nkb6 1:1.5:3 0.500 ssb6 1:1.5:3 0.489 nzs6 1:1.5:3 0.478 sgb6 1:1.5:3 0.478 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٣ table 3: range of measured properties of the tested concrete mixes mix notation compressive strength mpa upv m/sec rn w/c ratio agg/cement ratio density kg/m3 nbb 25.02-45.2 4573-4870 21.2-27.3 0.444-0.557 6 or 4.5 2296-2381 sbb 19.64-41.42 4310-4813 23.7-30.7 0.478-0.60 6 or 4.5 2309-2379 nab 25.91-34.22 4412-4839 23.4-31.3 0.45-0.55 6 or 4.5 2353-2415 sab 20.27-31.84 4412-4639 25.3-27.4 0.478-0.60 6 or 4.5 2295-2399 nkb 18.82-33.41 4167-4518 18.8-33.4 0.50-0.628 6 or 4.5 2296-2379 skb 24.12-33.19 4265-4478 24.1-33.2 0.50-0.628 6 or 4.5 2305-2360 nzb 22.40-31.45 4412-4545 22.4-31.5 0.444-0.557 6 or 4.5 2343-2418 szb 28.02-43.08 4335-4663 28.0-43.2 0.50-0.60 6 or 4.5 2315-2389 nsb 23.24-35.48 4369-4545 23.2-35.5 0.478-0.557 6 or 4.5 2335-2383 ssb 26.77-35.94 4455-4615 26.8-35.9 0.489-0.60 6 or 4.5 2337-2396 nas 20.93-42.12 4186-4687 20.4-42.1 0.444-0.60 6 or 4.5 2357-2441 sas 29.02-42.28 4434-4687 29.0-42.3 0.444-0.557 6 or 4.5 2349-2451 nks 27.95-32.94 4360-4545 29.3-29.5 0.478-0.60 6 or 4.5 2359-2387 sks 34.60-50.47 4390-4580 28.2-31.1 0.478-0.60 6 or 4.5 2378-2418 nzs 23.05-32.94 4478-4712 27.1-31.7 0.473-0.60 6 or 4.5 2358-2471 szs 22.50-33.05 4310-4580 27.9-30.4 0.444-0.557 6 or 4.5 2403-2481 nss 18.07-30.98 4592-4813 27.8-32.7 0.473-0.60 6 or 4.5 2388-2464 sss 27.18-35.60 4523-4737 27.2-32.6 0.444-0.557 6 or 4.5 2386-2474 ngb 22.83-27.76 4390-4545 28.2-30.4 0.478-0.60 6 or 4.5 2385-2422 sgb 21.91-26.03 4348-4412 27.0-30.6 0.478-0.60 6 or 4.5 2374-2460 table 4: regressions constants of groups cast with ordinary portland cement reg. no. a0 a1 a2 s.e mpa r reg. no. a0 a1 a2 s.e mpa r nab nks nab1 0.445 1.676 0.498 1.39 0.871 nks1 3.3x10-5 2.797 2.826 0.47 0.990 nab2 0.272 3.053 1.85 0.759 nks2 7.8x10-5 8.511 1.16 0.941 nab3 2.734 0.735 1.69 0.803 nks3 5.9x10-5 3.908 ٠.66 0.981 nbb nsb nbb1 0.1755 -0.553 1.888 1.04 0.991 nsb1 7.8x10-5 9.136 -0.34 1.11 0.928 nbb2 1.92x10-6 10.722 3.55 0.897 nsb2 1.39x10-4 8.028 1.12 0.927 nbb3 0.096 1.809 1.05 0.991 nsb3 0.028 2.103 1.55 0.854 nas nss nas1 1.87x10-4 4.49 1.545 1.44 0.978 nss1 0.0671 1.055 1.278 0.88 0.952 nas2 6.64x10-5 8.614 1.88 0.963 nss2 0.0330 4.357 1.06 0.931 nas3 0.0011 3.044 1.91 0.962 nss3 0.0924 1.659 0.90 0.950 ngb nzb ngb1 0.0012 3.264 1.492 0.43 0.957 nzs1 9.55x10-4 5.147 0.786 0.97 0.963 ngb2 0.010 5.216 1.10 0.823 nzs2 2.48x10-4 7.762 1.48 0.912 ngb3 0.0189 2.138 0.94 0.873 nzs3 0.1595 1.577 1.91 0.847 nkb nzs nkb1 1.29x10-3 7.062 -0.211 0.28 0.998 nzb1 0.01849 7.287 1.126 2.03 0.715 nkb2 1.19x10-3 6.656 0.32 0.997 nzb2 0.08616 3.790 2.19 0.655 nkb3 2.88x10-3 2.795 2.55 0.856 nzb3 1.9157 0.794 2.56 0.468 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٤ table 5: regressions constants of groups cast with sulphate resisting portland cement reg. no. a0 a1 a2 s.e mpa r reg. no. a0 a1 a2 s.e mpa r sab sks sab1 0.0008 4.346 1.176 1.01 0.965 sks1 1.55x10-4 4.727 1.557 0.84 0.984 sab2 0.0022 6.258 1.21 0.949 sks2 1.94x10-7 12.67 1.82 0.922 sab3 0.001 3.084 1.62 0.908 sks3 0.0164 2.283 1.18 0.968 sbb ssb sbb1 1.42x10-4 5.774 1.037 0.98 0.991 ssb1 0.0677 1.008 1.396 1.25 0.935 sbb2 1.806x10-5 9.411 1.47 0.981 ssb2 6.44x10-4 7.145 1.70 0.875 sbb3 7.973x10-3 2.459 1.90 0.968 ssb3 0.164 1.588 1.27 0.933 sas sss sas1 6.11x10-3 4.8 0.405 0.67 0.993 sss1 0.0128 3.961 0.505 0.63 0.98 sas2 1.67x10-3 6.554 0.97 0.985 sss2 6.32x10-3 5.539 0.76 0.971 sas3 0.4256 1.309 1.83 0.945 sss3 0.173 1.528 1.13 0.933 sgb szs sgb1 2.19x10-4 5.013 1.272 0.37 0.99 szs1 3.30x10-5 2.192 3.060 0.81 0.974 sgb2 1.63x10-5 9.644 1.03 0.926 szs2 3.16x10-3 6.042 1.39 0.922 sgb3 0.02074 2.130 0.91 0.943 szs3 8.87x10-6 4.422 0.99 0.961 skb szb skb1 0.0029 5.372 0.333 0.27 0.998 szb1 9.37x10-4 3.037 1.775 0.78 0.987 skb2 1.75x10-3 6.440 0.51 0.993 szb2 4.08x10-4 7.496 2.12 0.905 skb3 0.152 1.580 2.02 0.885 szb3 6.42x10-3 2.578 1.34 0.963 table 6: regressions for concrete with ordinary portland cement and all aggregate types ordinary portland cement ( all groups: 60 points : 360 cubes ) all aggregate types rs.empaa5a4a3a2a1a0 regression no. 0.8332.73-3.3240.085-0.5430.7553.069504.882n1 0.8122.89-0.053-0.5520.2673.0550.0857n2 0.8012.96-2.90.7124.31137.621n3 0.7783.100.3374.340.0126n4 0.7613.214.7150.0219n5 0.4404.440.9011.432n6 table 7: regressions for concrete with sulphate resisting portland cement and all aggregate types sulphate resisting portland cement ( all groups: 60 points : 360 cubes ) all aggregate types rs.empaa5a4a3a2a1a0 regression no. 0.8483.20-3.0580.127-0.5241.4742.25669.644s1 0.8183.47-0.032-0.3900.9062.9330.0145s2 0.8313.36-2.0821.5942.9541.266s3 0.8123.521.2203.3820.00315s4 0.7414.056.2490.00247s5 0.7583.941.9690.0421s6 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٥ table 8: general ranges of measured properties of the tested concrete mixes upv m/sec rn w/c ratio agg/cement ratio density kg/m3 4167-4870 18.8-43.2 0.444-0.628 4.5-6.0 2295-2481 20 24 28 32 36 40 44 predicted cube strength mpa 16 20 24 28 32 36 40 44 48 o bs er ve d c ub e st re ng th m pa figure 1: observed versus predicted compressive strength values of regression n1. 20 24 28 32 36 40 44 48 predicted cube strength mpa 16 20 24 28 32 36 40 44 48 o bs er ve d c ub e st re ng th m pa figure 2: observed versus predicted compressive strength values of regression s1. ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٧٨ النجف األحياء السكنية لمدينتيفي دراسة حقلية عن أهم مصادر التلوث الضوضائي والكوفة حسين شاكر محمود البحراني جامعة الكوفة –كلية الهندسة خالصة يتلخص هذا البحث في دراسة مستويات الضوضاء المختلفة التي يتعرض لها اإلنسان من خالل استمارة اسـتبيان كمـا فـي ، يتضمن االسـتبيان والكوفة النجف مدينتيمن مناطق مختلفة في شخص) ١٥٠(وزعت على عينة عشوائية مكونة من ) ١(الشكل طرح سؤال عن أهم مصادر الضوضاء التي يتعـرض لهـا الشـخص وأسـئلة أخـرى تتعلـق بـالعمر والحالـة االجتماعيـة والمهنـة وعنـوان ضـاء، أهـم هـذه المصـادر مصـادر تسـبب الضو ) ٦(يعـاني مـن هـاتين المـدينتيننتيجة االستبيان أوضحت بأن المـواطن فـي . السكن مـن المـواطنين باإلضـافة إلـى مصـادر أخـرى مثـل حركـة %) ٥٢(كانت الضوضاء الناتجة من صوت المولـدات حيـث بلغـت النسـبة %)١٢(، لعب األوالد في الشارع %)٦(، المدارس %)٣(، الكالب السائبة %)٣(، األسواق الشعبية %)٢٤(المركبات حيــث أظهــرت نتــائج هــذا البحــث أن ضوضــاء المولــدات هــي )ضوضــاء المولــدات(ة المصــدر األول قــام الباحــث بــالتركيز علــى دراســ وأن فتـرة التعـرض وغيـر سـمعية،) مزمنـة ومؤقتـة(علـى الصـحة العامـة سـمعية تأثيرات ولها إحدى مصادر الضوضاء االجتماعية، – ٧٠(تتــراوح بــين فصــوت النـاتج مــن هــذا المصــدر شــدة ضــغط ال الواحــد، أمــايوم بـالســاعة ) ٢٠ – ١٢(لهـذا المصــدر تتــراوح بــين .ديسيبل حسب حجم ونوع المولدة وطريقة تشغيلها) ٩٢ fiel study of the most importance noise pollution sources in living regimes at al-najaf and al-kufa cities hussein shakir al – bahrani engineering collegeuniversity of kufa abstract this research includes studying the most importance sources of noise pollution at al – najaf and al-kufa cities by giving questionnaire paper (figure1) to (150) person in different living regimes at those two cities. this questionnaire asked the persons about their names , ages, jobs, social states, and addresses, then asked them what was the most noisy sources in their city. the result of the questionnaire was that there had been six sources of noise pollution at those two cities. those sources were: generator noise (52%), vehicles noise (24%), public markets noise (3%), loose dogs noise (3%), schools noise (6%), boysplay in the streets (12%). the researcher concentrated on the first source (generator noise) the results of the research were: the generator noisy source is one of the social noisy source causes auditory effects and not auditory effects on the public health of human, the exposure time are between (12 – 20) hours per day, and the sound pressure levels for this source are between (70 – 92) decibel depending on the ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٧٩ size, quality, and the method of operation of the generator. :مقدمة تمهيدية والضوضــاء وان . اآللــةحيانــا هــو مــن ابــرز ســمات عصــر أو الضــجيج كمــا يطلــق عليــه أإن الضوضــاء ، ولكنهـا مشـكلة بيئيـة تـؤثر علـى الكيماويـةات البيئيـة كالسـموميات كانت ال تبدو قاتلة كما هـو حـال بعـض الملوثـ )١٩٨٣،احمد(.وهي بذلك تساهم بشكل فعال في تردي الوضع البيئي وسعادته وراحته، اإلنسانصحة وهـــذه . إن األصـــوات جـــزء ال يتجـــزأ مـــن الحيـــاة اليوميـــة لإلنســـان، وأصـــبحت إحـــدى الســـمات التـــي تميـــزه كمـا . دة فهـي تمـده بالمتعـة واالسـتمتاع مـن خـالل سـماعه للموسـيقي أو ألصـوات الطيـوراألصوات لهـا مزايـا عديـ أجـراس البـاب، أو : أنها وسيلة ناطقة لالتصال بـين كافـة البشـر، وتعتبـر أداة لتحـذير اإلنسـان وتنبيهـه متمثلـة فـي لمجتمعـــات الحديثـــة، لكـــن اآلن وفـــي ا. الخلـــل فـــي الســـيارات: كمـــا تخبـــره بوجـــود خلـــل مـــا مثـــل. صـــفارات اإلنـــذار بـدر الـدين ( الضوضـاء"أصبحت األصوات مصدر إزعاج لإلنسان، ال يريـد سـماعها لـذلك فهـي تنـدرج تحـت اسـم ،٢٠٠٤( ن أو مهني معين، ولكن من الواضح أن االهتمام بمشكلة الضوضاء ليس من اختصاص قطاع هندسي إ مـات مختصـي الصـحة المهنيـة ومهندسـي العـزل هي من اهتما) الخ-المعامل(جواء العمل أمشكلة الضوضاء في ن تكـون مشـكلة اجتماعيـة قـد تعـم حيـا سـكنيا أجواء العمـل بـل مـن الممكـن أالضوضاء ال تقتصر على .الصوتي ترفيهية وغيرها، لذا فان دور المهندس المدني يبدو واضحا في التعامل مـع أومنطقة تجارية أومدينة صغيرة أو المنشـــات، قامـــةإلعنـــد التخطـــيط و ة عليهـــا خاصـــة عنـــد تصـــميم منظومـــات الطـــرق، الضوضـــاء ومحاولـــة الســـيطر وللمهنـــدس الميكـــانيكي دور كبيـــر فـــي الســـيطرة علـــى ضوضـــاء اآللـــة، ويتعامـــل المهنـــدس المعمـــاري مـــع تحديـــد ت البلدية قيودا للسيطرة على الضوضاء الناجمـة عـن فعاليـا اإلداراتوتفرض العديد من .األبنيةالضوضاء داخل الضوضـاء عنـد بتـأثيركـذلك فـان الجهـات البيئيـة غالبـا مـا تفـرض وجـود فصـل خـاص . المشـاريع المختلفـة إنشاء )١٩٨٣،احمد(.معينةمنطقة أولمدينة األرضمحور مروري وكذلك تحديد طبيعة استخدامات إلنشاءالتخطيط :الغرض من البحث مـدينتيء تـأثيرا علـى المجتمـع المـدني فـي الغرض من هذا البحـث هـو معرفـة أكثـر مصـادر الضوضـا إن ومحاولـة وأجناسـهم أعمـارهمودراسة تأثير هذه المصادر علـى الصـحة العامـة للمـواطنين بمختلـف والكوفة النجف .والمتطلبات البيئية العالمية يتالءمالحلول المناسبة لتقليل مستوى الضوضاء بما إيجاد :الدراسات السابقة سـنوات فـي )١٠ – ٨(عمر اإلنسان يـنقص مـن أنالتي قام بها العلماء النمساويون إلى تشير بعض الدراسات ضـغط الـدم عنـد أنوقـد أظهـرت الدراسـات . المدن الكبيرة بالمقارنة مع سكان األريـاف بسـبب التلـوث الضوضـائي المطـار و سـرعتهم أطفال المدارس الواقعة بالقرب من مطار لوس أنجلوس أعلى من أطفال المدارس البعيدة عن ، لة سـرعان مـا يرموهـا جانبـا وال يحـاولوا إعـادة حلهـا أوعند إخفاقهم في حـل المسـ، في حل المسائل الرياضية اقل فـان واحـدًا مـن كـل أربعـة رجـال و واحـدة مـن كـل ، و حسب النتائج فـي بعـض الدراسـات التـي نشـرت فـي إنجلتـرا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٠ مليون عامل في الواليات المتحدة )١٦(و يشكو ،،، لضوضاء ثالثة نساء يعانون من األمراض العصبية بسبب ا و تقدر األضرار التي تصيب العمال و تؤدي إلى االنقطاع عـن ، من الضوضاء في المصانع التي يعملون فيها )٢٠٠٣، حسوني(.مليارات من الدوالرات سنوياً )٤(العمل بنحو جيج الصــادر عــن الســيارات والطــائرات والمصــانع وعلــى صــعيد آخــر قــدرت وزارة البيئــة األلمانيــة أن الضــ إنســان ســنويًا، وٕاصــابة مئــات اآلالف بثقــل الســمع وضــعف التركيــز واضــطرابات )٢٠٠٠(وغيرهــا يــودي بحيــاة ويعـزز .وتشير دراسة حديثة نشرت فـي بـرلين وأجريـت علـى األطفـال أن الضـجيج يضـعف مناعـة األطفـال .مالنو طفل تتـراوح أعمـارهم ) 400(ة ويضعف قدراتهم على التعلم، وشملت الدراسة مخاطر إصابتهم بأمراض الحساسي سـنة يعيشـون فـي منطقـة أوسـتيروده األلمانيـة وخضـعوا إلشـراف األطبـاء المختصـين طـوال شـهر )١١ – ٥(بـين )٢٠٠٧،محمدي (.في إحدى المصحات لشـــك عالقـــة الضوضـــاء وكانـــت دراســـة أخـــرى مهمـــة حـــول الضـــجيج فـــي بافاريـــا أثبتـــت بشـــكل ال يقبـــل ا والضجيج المسائي بأمراض األطفال، حيث أجريت دراسة سريرية على األطفال المقيمين في المناطق القريبة مـن أثناء عمل المطار، وبعد مدة سنتين مـن نقـل المطـار مـن مكانـه، لـوحظ مـن خـالل نتـائج )ريم –ميونيخ (مطار فال مثل الربو وضعف التركيز وقلة المناعة قد أختفت أو علـى الدراسة أن الكثير من األمراض التي تصيب األط )٢٠٠٤،بدر الدين (األقل قلت كثيرًا لدى األطفال بعد نقل المطار من موقعه أما فيما يخص الدراسات المحلية، فهناك ندرة في الدراسات والبحوث المنشورة في مجال الهندسـة المدنيـة وفي محافظـة النجـف األشـرف، ال يوجـد قسـم . اء السكنية للمدن العراقيةوالتي تهتم بموضوع الضوضاء في األحي .يهتم بموضوع التلوث الضوضائي في دائرة حماية وتحسين البيئة في المحافظة :تعريف الضوضاء فهــي أذن أصــوات خشــنة غيــر ، هــي تلــك األصــوات التــي ال ينســجم لســماعها اإلنســان و ال ينبســط لهــا باإلضــافة ، ي مجملهــا إلــى معنــي واضــح بعكـس األنغــام الموســيقية التــي يطــرب لهــا اإلنســانال تــؤدي فــ، منتظمـة )٢٠٠٥،العيساوي(. ذن بشدةتؤدي إلى اهتزاز طبلة األ التيإلى إنها األصوات ذات التردد العالي ألن إدراك الصــوت يتوقــف علــى قــدرة الجهــاز العصــبي علــى فســيولوجيو للصــوت معنيــين أولهــا معنــى و يقصــد بــه تلــك فيزيــائيو المعنــي الثــاني ، ســماعها اإلنســانباله و تحليلــه و هنــاك أصــوات ال يســتطيع اســتق )٢٠٠٤،بدر الدين . (عدم وجوده أوالموجات التي تعرف بالصوت بغض النظر عن وجود مستقبل لها وفي الطبيعة ، نيةذبذبة في الثا) ٢٠٠٠ – ١٧(واآلذن البشرية تستطيع أدراك األصوات التي تتراوح بين )٦(. باألصوات الفوق و التحت الصوتيةتوجد أصوات اقل وأعلى من هذين الترددين و يعرفان تعتبر الضوضاء من أنواع التلوث العديدة حيث أنها صنفت بأنهـا ضـارة علـى صـحة اإلنسـان، الحيـوان، يومـــا بعـــد يـــوم وخصوصـــا فـــي الطيـــور والنبـــات وأشـــياء غيـــر حيـــة أخـــرى، إن مشـــاكل التلـــوث الضوضـــائي تـــزداد ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨١ ، بجانب المناجم، الطرق السريعة، المطارات، المناطق الصناعية ومناطق "المزدحمة بالسكان"المناطق الحضرية ) ٢٠٠٣،حسونة( ..أخرى توجد بها حركات إنشاء كالبناء وتنفيذ مشاريع وسائل النقل، ضوضاء ضوضاء: مثل" الضوضاء"هناك أنواع عديدة للتلوث السمعي أو ما يطلق عليه )٢٠٠٤الدين، بدر(.اجتماعية، ضوضاء صناعية، وضوضاء الماء : الصوتية األمواج التلــوث البيئــي التــي يخشــى مــن أنــواعهــي فضــالت طاقــة وهــي علــى عكــس بقيــة ،الضوضــاء فــي الواقــع هذا النوع من ويأخذ، مصدرعند انبعاثها فقط وتزول مباشرة بزوال ال تأثيرهاومتبددة وينحصر آنيةتراكمها، فهي المختلفة وخاصة في الهواء على شكل نبضات من ارتفاع األوساطالصوتية التي تنتقل في األمواجالتلوث شكل .من تذبذب جسم ما أصالوانخفاض في ضغط الوسط الناقل والذي يتسبب يـب المـألوف حيـث تمثـل الضغط في الوسط الناقل للصوت بمنحني الج أوالتعبير عن الكثافة وباإلمكان قرارين متعاقبين ما يعرف بطول الموجة كما يعرف عدد الموجات المارة عبر نقطـة معينـة أوالمسافة بين سمتين حيث )hz(الهيرتز بوحدة أحياناويعبر عن التردد . في كل ثانية بالتردد ويمثل ارتفاع الموجة مدى علو الصوت ) ١٠٠٠(تــردد الصــوت مــن مصــدر مــا هــو أنفــي الثانيــة لــذلك يقــال يمثــل الـــهيرتز مــرور موجــة صــوتية كاملــة ويجب . موجة في الثانية ) 1000(هو )مستوى معين أو(كان عدد الموجات المارة خالل نقطة معينة إذاهيرتز .الواحدال يختلط مفهوم التردد مع سرعة الصوت الذي هو ثابت في الوسط أن متـر بالثانيـة )340(الحرارة والضغط ينتقل الصوت بسرعة تساوي وفي الهواء وتحت ظروف قياسية من :الموجةتقريبا ويمثل هذا الرقم الثابت حصيلة ضرب التردد في طول الواحدة )١( )طول الموجة(× ) التردد= (سرعة الصوت حـدة الصـوت وتعتمـد. ونظرا لثبوت سرعة الصوت فـان العالقـة بـين التـردد وطـول الموجـة سـتكون عالقـة عكسـية )pitch ( الحادة األصواتعلى تردد الموجة الصوتية حيث تكون) عالية التردد في حين تكـون ) الصفارةكصوت ذات التـردد األصـواتالبشرية تمييـز األذنوتستطيع . واطئذات تردد ) كصوت منبه الباخرة (الغليظة األصوات ) 200 10000(مـا يكـون للتـرددات الواقعـة بـين كفـأأهيرتـز ويكـون التمييـز ) 20000 إلـى 20(الذي يقع بـين هــذه أننســى يّ◌ أالولكــن يجــب . ز تــهير ) 4000 إلــى 300( الصــوت البشــري فيتــراوح تــردده بــين أمــاهيرتــز مـــن مصــادر الضوضـــاء األمــواجتصــدر هـــذه أنوينـــدر ) التــردد أحاديـــة(نقيــة ألصـــواتالصـــوتية هــي األمــواج النقيـة فهـي فـي الغالـب تكـون مـن تركيبـة متنوعـة مـن األصـواتابعد ما تكـون عـن الضوضاء هي أن إذالمألوفة نســق أيذات الضــغوط المختلفــة ولكــل منهــا عــدد كبيــر مــن التــرددات بحيــث ال يمثــل الصــوت النــاتج األصــوات أهمواالرتفاعات ولكن األطوالثابت بل مجرد تركيبة عشوائية من موجات مختلفة . )١٩٨٣،احمد(. ضوضاء ألنهارفضها السامع ي أنما يميزها يوضح مستوى الضوضاء المسموح بها عالميا حسب تقارير منظمة الصحة العالمية )١(الجدول ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٢ أن هذه المستويات ال توجد في كثير من المدن المعروفة بتلوثها الضوضائي إال. لمناطق مختلفة داخل المدن إلىحيث يصل معدل الضوضاء في هذه المدن ) ناي، وكلكتابومباي، دلهي، ش(العالي وخاصة المدن الهندية )٢٠٠٤بدر الدين،( .درجة هيرتز) ٤٥(أكثر من :قياس الضوضاء الصـــوت كمـــا ذكـــر ســـابقا هـــو عبـــارة عـــن دورات متناوبـــة مـــن الضـــغط العـــالي والمـــنخفض للهـــواء مقارنـــة كبيـرة أرقامـافاضات عـن الضـغط الجـوي تبلـغ هذه االرتفاعات واالنخ أنوال يحسب المرء .السائدبالضغط الجوي هــذه الفــروق الضــغطية تقــاس بــالجزء مــن أن أيال تتجــاوز الجــزء الصــغير مــن مقــدار الضــغط الجــوي أنهــابــل إدراكالبشـرية األذنوتسـتطيع )كيلو باسكال ١٠٠(أو ) بار ١(المليون من الضغط الجوي القياسي الذي يساوي تتـراوح بـين حيـث أحيانـاشدة الضغط الصوتي كما يعبر عنهـا أوالضغوط الصوتية المستويات المختلفة من هذه مــايكرو 1000( هقــدر األذنيكــاد يمــزق طبلــة أعلــىوحــد )مــايكرو بــار ٠.٠٠٠٢(يكــاد ال يــدرك قــدرة أدنــىحــد . إمكاناتـــــهقيـــــاس كـــــان مهمـــــا كانـــــت أليجهـــــاز الكترونـــــي أييســـــتحيل علـــــى اإلدراكوهـــــذا المـــــدى مـــــن ) بـــــار )١٩٨٣،احمد(. استخدام الضغط الصوتي بوحدات المايكرو بار التي تتباين ضمن مجـال رقمـي واسـع يعـد أنمن اليقين و . لألصــواتالبشــرية ال تتــأثر بشــكل طــردي بســيط للضــغوط المختلفــة األذن أن إلــى إضــافةغيــر مناســب أمــرا ، بســيط مــع ضــغط الموجــة الصــوتية خطــي ال يتناســب بشــكل األذنارتفــاع الصــوت الــذي تحســه إن أخــرىبعبــارة ولتالفـي اسـتخدام ضـغط . الضـعف إلـىبارتفاعـه األذنمضاعفة الضـغط الصـوتي ال يزيـد شـعور أنوهذا يعني فقــد اســتخدمت عالقــة لوغارتيميــة تــدعى ، الصــوت بســبب مســاوئ مثــل هــذا القيــاسالموجــة الصــوتية فــي قيــاس ال تمثل مقدارا فيزياويا بالمفهوم المطلـق كمـا )db(المقياس ووحدات هذا . لهذا الغرض )db(الديسيبل مقياس بمســـتوى يعبـــر عنـــه ) db(وقيـــاس الضوضـــاء بوحـــدة الديســـيبل . و الحـــال مـــع وحـــدات قيـــاس ضـــغط الصـــوتهـــ مقارنـة بأوطـأ ضـغط ) spl(الـ إيجادويجري ) . spl(واختصارا ) sound level pressure( الضغط الصوتي -:peirce,1999)(مايكروبار ويعبر عن ذلك حسابيا كاالتي )0.0002(اي األذنللصوت تدركه )2(log20)( 10         = refp p dbasspl :حيث ان p = مايكروبار(ضغط الصوت الحقيقي( pref = مايكروبار 0.0002( ويساوي ضغط القرار ( ي فـأن ذلـك ال يعنـ ديسـيبل عنـدما يسـاوي صـفر) spl(وعلى هـذا االسـاس فـأن مسـتوى ضـغط الصـوت وكمـا ذكـر سـابقا فـان الحـد المـؤذي لـالذن مـن ). ٢(ويض ذلك فـي المعادلـة انعدام الصوت ويمكن ادراك ذلك بتع ). db 134(قدره )spl(والذي يعطي )مايكروبار 1000(الضغوط الصوتية هو ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٣ على مسـتوى ضوضـاء ) db 3(مصدرين متساويين للضوضاء يزيد فقط أيوكقاعدة عامة فأن محصلة 15(مصدرين للضوضاء يبلـغ الفـرق بـين مسـتويهما اكثـر مـن أيكذلك فأن ،ما مهما كان هذا المستوىكل منه db ( وهــذا يعنــي ان محصــلة ضوضــاء حفــارتين للخنــادق . األعلــىفــان المحصــلة ســتكون نفــس مســتوى المصــدر )back hoes ( سـيكون)86 db ( اذا كـان مسـتوى ضوضـاء كـل منهمـا)83 db (ونكريـت وان محصـلة كسـارة ك )spl = 100 db ( وقاشـطة)spl = 85 db ( هـي)100 db ( البشـرية سـوف لـن تميـز صـوت األذناي ان مســـتوى قيـــاس بعـــض االصـــوات بوحـــدة )٢(الجـــدول ويوضـــح .كثيـــرا األعلـــىالقاشـــطة بوجـــود ضوضـــاء الكســـارة ) ١٩٨٣احمد (الديسيبيل لحســاب مســتوى الضوضــاء عنــد وجــود فيوضــح الطريقــة المســتخدمة )٣(يوضــح الشــكل ) ١(امـا الشــكل فاإلعـداد علـى المحـور األفقـي تمثـل الفـرق بـين المجمـوع الكلـي ) peirce ، ١٩٩٩(اكثر مـن مصـدر للضوضـاء تمثل الفرق بين ) ١(لمستوى الضوضاء وبين مصدر الضوضاء األدنى ، واإلعداد على المحور العمودي للشكل .مصدر الضوضاء االدنى المجموع الكلي لمستوى الضوضاء وبين مستوى :ظاهرة الحجب عند تولد مصدرين للصوت فان الصوت االعلى يحجب الصوت االوطأ وهذه الحالة يطلق عليها بظاهرة ديســيبل مــن ) ١٠(حيــث وجــد مــن الدراســات أنــه اذا كــان مصــدر الصــوت الخلفــي أكبــر بـــ. (masking)الحجــب )٣(الجــدول . ى حجــب وازالــة مصــدر الصــوت االمــاميمصــدر الصــوت االمــامي فــان الصــوت الخلفــي يعمــل علــ يوضح مستويات ضغط الصوت مقاس بوحدة الديسيبل لمستويات مختلفة من الحديث على مسـافات مختلفـة عـن الن ةديســيبل مــن ماكنــة مصــنع تجعــل المحادثــة العاديــة بــين شخصــين مســتحيل) ٨٠(مــثال ف .مصــدر االســتقبال .ديسيبل) ٦٠( لحديث العاديصوت الماكنة يعمل على حجب صوت ا )٥(: التأثيرات السلبية للضوضاء ولكــنهم ، هــا العمــر والجــنس والحالــة النفســيةيتبــاين البشــر فــي تــأثرهم بالضوضــاء بســبب عــدة عوامــل من :جميعا يتأثرون بالضوضاء بشكلين رئيسين .تأثيرات سمعية مؤقتة ودائمية. 1 .تأثيرات غير سمعية . 2 ي تأثيرات الضوضاء على جهاز السمع فأن هذا التأثير يتراوح من الفقـدان أ، أثيرات السمعية فبالنسبة للت فقـدان السـمع الـدائمي والـى االذى الفيزيـاوي وانبعـاج طبلـة إلـى األصـواتالسمعي المؤقت للمستويات الواطئة من عند التعرض للضوضاء ولكن ) db 80(الــسمعي اذا كان مستوى الضوضاء دون ويندر ان يتولد اي ضرر . األذن إلـىامـا عنـد التعـرض لفتـرات طويلـة . فـأن الفقـدان السـمعي المؤقـت سـيكون اكيـدا ) db 130(و ) a( 80 db((التـي تتـراوح بـين فــأن الفقــدان الســمعي الــدائم ســيكون هــو النتيجــة الحتميــة كمــا يحــدث لعمــال صــناعات الغــزل ) a (95 db((ضوضــاء تتجــاوز ال ولكــن يفقــد الشــخص ، وال يحــدث الفقــدان الســمعي الــدائم بــنفس المقــدار لكــل درجــات التــردد . ض الصــناعات المعدنيــة والنســيج وبعــ واذا اسـتمر التعـرض فأنـه يبـدأ بفقـدان السـمع ، المعرض للضوضاء لسـاعات طويلـة يوميـا سـمعه فـي مجـاالت معينـة مـن التـردد اوال ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٤ ) a( 100 db((ضوضـاء مسـتواها إلـىن مقـدار الفقـدان السـمعي فـأن التعـرض والعطـاء فكـرة واضـحة عـ. في مجاالت تردد اكبر امــا علــى مســتوى الفقــدان الســمعي الــدائم فــأن تعــرض . ولمــدة ســاعة واحــدة فقــط قــد يحــرم الشــخص مــن حــدة الســمع لمــدة يــوم كامــل د هـذا الشـخص بعـد ثمـاني ان يفقـ إلـىولمـدة ثمـاني سـاعات فـي اليـوم سـيؤدي ) a (95db((ضوضاء عمل مسـتواها إلىالشخص ويأتي على رأس التأثيرات غير السمعية للضوضاء التأثير على انتظام دقات القلـب .من حدة سمعه) a (15db((سنوات ما مقداره اما التأثيرات غير السمعية االخرى التي تعد اكثر اهمية فهـي تسـبب الضوضـاء فـي االنزعـاج وعـدم . وضغط الدم والجهاز التنفسي ظــاهرة زيــادة االجــازات المرضــية إلــى إضــافةالنفســية وفقــدان التركيــز والــذي يــؤثر ســلبيا علــى انتاجيــة العمــال فــي الصــناعة الراحــة تـداخل الضوضـاء إلـى إضـافةاما على مستوى الحياة المدنية العامة فأن الضوضاء تحرم الناس من النـوم العميـق . وحوادث العمل رهــا كثيـر تعــد الضوضــاء عنصــرا ســلبيا فــي المجتمعـات وامــاكن العمــل مــن الضــرورة الســيطرة لهــذه االســباب وغي. مـع حــديث النــاس . عليها )٥( :أنواع التلوث الضوضائي وتأثيراته .هو تعرض دائم ومستمر لمصدر الضوضاء وقد يحدث ضعف مستديم في السمع-:تلوث مزمن -١ لمصـدر أو مصـادر الضوضـاء ومثـال ذلـك التعـرض هـو تعـرض لفتـرات محـدودة -: تلوث مؤقت ذو أضرار فسـيولوجية -٢ .للمفرقعات ويؤدي إلى إصابة األذن الوسطى وقد ُيحدث تلف داخلي تعــرض لفتــرة محــدودة لمصــدر ضوضــاء مثــال ذلــك ضــجيج الشــارع واألمــاكن المزدحمــة أو -:تلــوث مؤقــت دون ضــرر -٣ حيــث تقــاس شــدة الصــوت بوحــدة .ة بســيطةالــورش، ويــؤدي إلــى ضــعف فــي الســمع مؤقــت يعــود لحالتــه الطبيعيــة بعــد فتــر كما ذكر سابقًا، وكل األصوات التي تسمع يوميًا تندرج تحت مستويات رئيسية مقاسة بالديسيبل وهذه المسـتويات ) ديسيبل( -:هي مــا ويــؤدي إلــى تــأثيرات وردود فعــل عكســية تتمثــل بــالقلق والتــوتر فهــي تــؤثر فــي قشــرة المــخ م -: ديســيبل) ٥٠-٤٠(المســتوى -أ .يؤدي إلى عدم ارتياح نفسي واضطراب وعدم انسجام صحي لـه تـأثيرات سـيئة علـى الجهـاز العصـبي ويـؤدي إلـى اإلصـابة بـآالم شـديدة فـي الـرأس ونقـص -: ديسيبل) ٨٠-٦٠(المستوى -ب .)كوابيس(القدرة على العمل ورؤية أحالم مزعجة .السمع ويحدث اضطرابات في الجهاز العصبي والجهاز القلبي يؤدي إلى انخفاض شدة -:ديسيبل ) ١١٠-٩٠(المستوى -جـ يسبب ألمًا للجهاز السـمعي وانعكاسـات خطيـرة علـى الجهـاز القلبـي الوعـائي كمـا يـؤدي -:ديسيبل ) ١٢٠(المستوى أعلى من -د .إلى عدم القدرة على تمييز األصوات واتجاهها )٧، ٥( :السيطرة على الضوضاء : اآلتيةاالختيارات أحدبتقلل الضوضاء .تقليل شدة الضوضاء من مصدرها : أوال عن طريق وضع حواجز تطيل مسار الموجة ذلك المسار إطالة أومقاطعة الضوضاء خالل مسارها : ثانيا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٥ .الصوتية للضوضاء وبالتالي تؤدي الى تشتتها واندثارها . فةباستخدام واقيات اإلذن المختل السامع أذنحماية : ثالثا فعلى مستوى تقليل شدة الضوضاء من مصادرها . مناسبة لها إمكاناتولكل اختيار من هذه االختيارات جيـــدة لتقليـــل احتكـــاك االلـــة الصـــناعية ومعالجـــة ضوضـــاء الســـيارة باســـتخدام إمكانـــاتوفـــرت التكنلوجيـــا الحديثـــة كـــذلك فــأن صــيانة المكـــائن . الســيارة آليــاتتقليـــل ضوضــاء الماكنــة وبقيـــة إلــى إضــافةمتطـــورة أصــواتكاتمــات وهناك امكانية اضافية لتقليل ضوضاء المرور . والسيارات وتزييتها المنتظم هما من اهم وسائل تقليل الضوضاء ولكـن ، بالشـارع اإلطـاراتوهـو احتكـاك ، لك يتحدد اهم مصادر ضوضـاء المـروروذلك بتقليل خشونة الشوارع وبذ . سطح االطار وذلك السباب تتعلق بسالمة القيادة أويل خشونة سطح الشارع ليس من الممكن المبالغة بتقل يتعـــذر تقليـــل شـــدة أنبعـــد ويـــأتيالحلـــول آخـــرالســـامع فهـــو فعـــال أذنوهـــو وقايـــة األخيـــراالختيـــار أمـــا ومثــل هــذه ) a (40 db((تخفــض مســتوى الصــوت بمــا يعــادل الـــ أنالجيــدة األذنواقيــات وبإمكــان. الصــوت األذناسـتخدام واقيـات أنورغـم اإلنشـائيةقيات مفيدة جدا للعـاملين فـي الصـناعة والمطـارات وعمـال المكـائن الوا اسـتخدامها يلقـى معارضـة حتـى مـن قبـل أنال بـل ، غير عملي لتجنب مصادر الضوضاء من قبل عامة الناس ك بسـبب تأثيرهـا علـى ردود فعـل وذالـ، عاليـة مـن الضوضـاء ولسـاعات طويلـة مسـتويات إلـىالعاملين المعرضـين .مستعمليها واتصالهم الكالمي مع بعضهم أومعظم الحلول الهندسية تنحصر في االختيار الثاني وهو مقاطعة الضوضاء بين مصدرها والسامع إن وذلك باستخدام الحواجز ومصادر الضوضاء لمنـع وصـول الضوضـاء بمسـتويات عاليـة .تطويل مسار الضوضاء .ع واستخدام المواد ذات العزل الصوتي الجيد في بناء جدران االبنيةالذنىالسام )١(: الوقائية لتقليل اثار الضوضاء اإلجراءات أهم. ١١ حيث اإلنسانخصوصا على أخطارهيتزايد االهتمام بالتلوث الضوضائي حيث تعددت مصادره وازدادت إجــراءاتلــذلك يتطلــب اتخــاذ اإلنســانلجســم خلــل فــي بعــض الوظــائف الحيويــة إحــداثيعمــل هــذا التلــوث علــى -:وقائية من اهمها ،اإلصالح المستمر للمكائن التي توجد بالمصانع وبهذه الخطوة من الممكن أن يقلل أو ُيعدم الضوضاء -١ المراقبة الصـارمة علـى الصـناعات وتعـديل العمليـات للسـيطرة علـى الضوضـاء أثنـاء إصـدار وتجديـد رخـص -٢ ، العمل إصــدار التشــريعات الالزمــة وتطبيقهــا بحــزم لمنــع اســتعمال منبهــات الســيارات ومراقبــة محركاتهــا وٕايقــاف تلــك -٣ ،المصدرة لألصوات العالية إن زراعـة األشـجار . تعتبـر النباتـات مـن أهـم الطـرق المتصـاص الضوضـاء خصوصـًا الضوضـاء النبضـية -٤ علـى طـول الطـرق َأو الشـوارع العاليـة يسـاعد فـي ) neem(الــتمـر هنـد و والبانيـان، وال، )casuarina(الــ مثـل ،تخفيض الضوضاء في المدن والبلدات ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٦ منــع اســتعمال مكبــرات الصــوت وأجهــزة التســجيل فــي شــوارع المدينــة والمقــاهي والمحــالت العامــة علــى ســبيل -٥ ،اءا لغاية الساعة الخامسة فجرامس العاشرةالمثال من الساعة عن طريق وسائل اإلعالم المختلفة ببيان أخطار هذا التلوث على الصحة البشـرية بحيـث نشر الوعي وذلك -٦ ،ن الفضاء الصوتي ليس ملكا شخصيايدرك المرء أ ،إبعاد المدارس والمستشفيات عن مصادر الضجيج -٧ ، كم ٣٠إبعاد المطارات عن المدن والمناطق اآلهلة بالسكان مسافة ال تقل عن -٨ .َأن تكون خطوط السكة الحديدية والطرق السريعة بعيدة عن المناطق السكنية قدر اإلمكانيجب -٩ )٧، ٥، ٤( :مستويات التعرض للضوضاء ومعايير التعرض ، اإلنسـانالتأثيرات السلبية للضوضاء الشديدة ومدى ضـررها علـى إلىفي الفقرات السابقة اإلشارةلقد تم كيفيـة حسـاب معـدالت الضوضـاء إلـىوال ، فتـرة التعـرض فـي تحديـد هـذا الضـرر يـةأهم إلـى اإلشـارةولكن لـم تـتم كخاصية صوتية مجردة من ) كقياس مستوى الصوت (من الضروري التمييز بين مقياس الضوضاء إن. المتغيرة م الخاصـة بالقيــاس وبـين تقيــيم الضوضـاء حيــث تـدخل فــي التقيــي األجهــزة باسـتخداملحظــة أيالممكـن قياســها فـي )rating (دة واالستجابة العوامل التي تحدد العالقة بين القيمة المجر إلى إضافة، عديدة منها فترة التعرض أمور . الموضوعية للضوضاء التعـرض يعرض قيم الضوضاء وما يقابلها مـن فتـرات تعـرض والتـي تعتمـد كمعـايير لفتـرات )٤(الجدول أمـروهـذا ، مسـتوى الصـوت ثابـت خـالل فتـرة التعـرض أندول وواضح من هـذا الجـ .المسموح بها في جو العمل خالل كل فترة اآللة أمامدون حراك الشخصاستقر إذا إال. غير واقعي خاصة بالنسبة لفترات التعرض الطويلة فــأن مســتوى الصــوت الــذي يتعــرض لــه ) كالشــارع والمنــزل وبقيــة المؤسســات (المفتوحــة األجــواءوفــي . التعــرض لذلك اعتمد فـي هـذه الحالـة علـى احتماليـة التعـرض ، وأخرىال بل بين دقيقة ، وأخرىير بين ساعة يتغ اإلنسان مـن نصـف التعـرض ويرمـز لـه بـالحرف ألكثـركـأن يؤخـذ المسـتوى الـذي يسـود ، بدال من مسـتوى الصـوت الثابـت )l 50 . ( فهـذا يعنـي ان ديسـبيل (70)فلـو كانـت قيمـة هـذا المعيـار فـي زاويـة احـد التقاطعـات المروريـة يسـاوي وبـنفس المنطـق فـأن . مستوى الضوضاء في ذلك التقاطع يتجاوز هذا الرقم نصف الوقـت وتقـل عنـه بقيـة الوقـت )l10( من ساعتين في اليوم ألكثريتجاوز هذا الرقم الضوضاء في ذلك التقاطع أنيعني ديسبيل (70) تساوي . المختلفة المنشاتبعض معايير مستوى الصوت في يبين ) ٥(والجدول ) عشرة بالمائة من الوقت ( :)عمل االستبيان( الجانب العملي مــن مــن كــال الجنســين و اســتمارة اســتبيان علــى عينــة عشــوائية مــن المــواطنين توزيــع البحــثتــم فــي هــذا عــن عامــة أســئلةيتضــمن االســتبيان . والمهــن يســكنون فــي أحيــاء تابعــة لمــدينتي النجــف والكوفــة األعمــارمختلــف الشخص مثل العمر والجنس والمهنة والحالة االجتماعية ومحل السـكن ثـم يـتم سـؤال الشـخص عـن أكثـر مصـادر .)١شكل(الضوضاء إزعاجا له ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٧ أمــا المنــاطق التــي شــملت . شخصــا) ١٥٠(حجــم العينــة التــي وزعــت علــيهم اســتمارة االســتبيان بلغــت إن -:كاآلتيفكانت بيانباالست االطباء، النصر، السالم، النفط، الغري، المكرمة، السعد، العدالة، الغدير، االميـر، :أحياء مدينة النجف -١ .المثنى، دور االساتذة، العسكري، الهندية، القادسية، الجزيرة، المدينة القديمة .ميسان، ميثم التمار، كندة، المدينة القديمة :أحياء مدينة الكوفة -٢ :نتائج االستبيان (microsoft access)البيانـات فـي برنـامج حاسـوب مناسـب إدخـالاالستبيان تم بعد جمع استمارات أساســيةبعــد ذلــك تــم اســتخراج النتــائج علــى شــكل نســب مئويــة حيــث تــم تحديــد ســتة مصــادر ،لتصــنيف البيانــات ، %)٥٢(ونسـبتها المولـدات ضوضـاءهـذه المصـادر هـي . مـدينتي النجـف والكوفـة وأحيـاءللضوضـاء فـي شـوارع ، ضوضـــاء%)٦(، ضوضـــاء المـــدارس %)١٢(ضوضـــاء ســـاحات لعـــب االوالد ، %)٢٤(مركبـــات ال اءضوضـــ )٣(الشكل في %).٣(الكالب السائبة ضوضاء، %)٣(الشعبية االسواق تــم البحــث فــي التــأثيرات الســلبية التــي تســببها الضوضــاء الناتجــة مــن صــوت مــن خــالل نتــائج االســتبيان مـن عينـة االسـتبيان تجـد بـأن %) ٥٢(لمعالجتها حيث أن االستبيان أوضح بـأن المولدات والمقترحات الضرورية صــوت المولــدات هــو األكثــر إزعاجــا وبمــا أن الدراســات والبحــوث العربيــة واألجنبيــة الســابقة لــم تقــم بالبحــث فــي ء السـكنية هـي على الحياة العامة للمواطنين وذلك الن انتشار المولدات فـي االحيـامن التلوث تأثير هذا المصدر عامة، وان عمل المولدات في أحياء مدن العراق لها خصوصية تميزهـا عـن بصورة حالة تتفرد بها المدن العراقية . غيرها من الدول العربية واالجنبية من حيث فترات التشغيل الطويلة ونوع المولدات المختلفة وفترات التعرض تبـر واحـدة مـن أكثـر مصـادر التلـوث الضوضـائي انتشـارا فـي ان المولدات التي تعمل بالـديزل والبنـزين تع العـراق بصــورة عامـة وفــي محافظـة النجــف بصـورة خاصــة فــال يخلـو حــي مـن أحيــاء المدينـة أو شــارع أو مؤسســة . حكومية من وجود مولدة تعمل على الديزل ، أما مولـدات البنـزين فمنتشـرة فـي معظـم الـدور والمحـالت التجاريـة وتـأثير ،وفتـرة التعـرض ،المولـدات تسـببهمسـتوى ضـغط الصـوت الـذي تقـدير ز في هـذا البحـث علـى تم التركيلقد .وطرق معالجة وتقليل هذا المصدر المسبب للتلوث الضوضائي ،هذا المصدر على الصحة العامة :مستوى قياس صوت المولدات مـن خـالل اسـتخدام ل والبنـزين الـذي تولـده مولـدات الـديز الضوضـاءلقد تـم فـي هـذا البحـث قيـاس مسـتوى (bruel & kjaer)جهـاز يـدوي صـغير الحجـم لقيـاس الضوضـاء بوحـدة الديسـيبل دنمـاركي المنشـأ مـن شـركة . (aa 1.5v)يعمل باستخدام أربع بطاريات نوع فحص الضوضاء على مولدة ديزل ذات إجراءلحساب مستوى الضوضاء الذي تولده مولدات الديزل، تم موجود ة في موقع دائرة العمل والشؤون االجتماعية فـي مدينـة النجـف علـى (kv 450)ل تصل إلى طاقة تشغي في البداية تم قياس مستوى ضوضاء المكان قبل تشغيل . الشارع العام الذي يفصل بين حي عدن وحي االنصار الطريـــق العـــام وهـــي الضوضـــاء الناتجـــة مـــن صـــوت المركبـــات علـــى )ديســـيبل ٩٢(المولـــدة فكـــان الجهـــاز يقـــرأ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٨ ). ديسيبل ٩٥(، بعد ذلك تم تشغيل المولدة فكانت القراءة على الجهاز تشير إلى والمكيفات وغيرها من األصوات ثــم تســقط علــى األفقــيديســبيل علــى المحــور )٢=٩٣-٩٥(يــتم وضــع الفــرق بــين القــرائتين ،)١(باســتخدام شــكل و ضوضاء لهذا النوع مـن مولـدات الـديزل يسـاوي مصـادر مساوية للصفر،أي ان مستوى ال المنحني فتكون النتيجة وتكــون )ديســيبل ٩٢(يســاوي الموجــودة فــي المكــان قبــل تشــغيل المولــدة األخــرى اإلضــافيةمصــادر الضوضــاء ومــن ثــم علــى ) ١(علــى المحــور العمــودي للشــكل ) ديســبيل ٣(النتيجــة مشــابهة عنــد تســقيط الفــرق فــي القــرائتين في ذلـك المكـان وفـي ذلـك )مولدة الديزيل والمصادر األخرى(تساوي مصدري الضوضاء المنحني وهذا دليل على الوقت ٩٣.٦(بعــد ذلــك وضــع الجهــاز عنــد مكتــب مــدير االحصــاء فــي الــدائرة فكانــت قــراءة الجهــاز تصــل إلــى ديزل يجـب يالحظ بأن فترة البقـاء اآلمنـة فـي هـذا المكتـب عنـد تشـغيل مولـدة الـ) ٤(وبالرجوع الى جدول ) ديسيبل ).ساعات ٥(أال تزيد عن أما بخصوص الضوضاء الناتجة من مولدات البنزين فقد تم إجراء الفحص علـى مولـدة بنـزين كبيـرة ذات وكانـت فتـرة إجـراء الفحـص عنـد السـاعة العاشـرة مسـاءا فـي (tigmax)نـوع ) أمبيـر ١٢(طاقة توليـد تصـل إلـى وبعـد التشـغيل ) ديسـيبل ٦٥.٥(الجهـاز قبـل تشـغيل المولـدة تسـاوي ، كانـت قـراءة )حـي الوفـاء(أحد أحيـاء النجـف مــن المحــور االفقــي الــى المنحنــي ) ديســيبل ٦(وعنــد تســقيط الفــرق بــين القــراءتين ) ديســيبل ٧١.٥(كانــت القــراءة مساويا ))١(الموجود على المنحني لشكل (وجد بان الفرق بين مصدري الضوضاء االعلى واالدنى ، )١(للشكل ) ديسـبيل ٦٥.٥(ديسيبيل وعند جمع هذا العدد مع مستوى مصدر الضوضـاء قبـل وبعـد تشـغيل المولـدة )٤.٨(ل يولــــد ) tigmax(اي ان هــــذا النــــوع مــــن المولــــدات .)ديســــيبل ٧٢.٣= ٤.٨+ ٦٥.٥( فــــان النتيجــــة ستســــاوي )ديسبيل ٧٠.٣(ضوضاء يبلغ مقدارها :لصوت المولدة فترة التعرض سـاعة ) ٢٠(التيار الكهربائي في بعض األوقات في محافظة النجف إلى أكثر مـن قد تصل فترة انقطاع طر لتشــغيل مولــدات الــديزل ومولــدات ضــأي أن المــواطنين فــي االحيــاء الســكنية والــدوائر الحكوميــة ست ،فــي اليــوم ألكثــر البنـزين لتعــويض الــنقص فــي الطاقـة الكهربائيــة ممــا يعنــي أن المــواطن سيضـطر لســماع ضــجيج المولــدات ســاعة فـــي اليــوم خـــالل فتــرة القيلولــة عنـــد ســاعات الظهيـــرة وفــي فتــرة النـــوم بعــد منتصـــف الليــل وهـــي ) ٢٠(مــن %) ٥٢(ان هـذا البحـث يبـين ان . للراحـة والهـدوء بعـد سـاعات العمـل المتعبـة اإلنسـانالساعات التي يحتاج فيهـا ديســـيبل ناتجـــة مـــن ضـــجيج ) ٩٢ – ٧٠(ضوضـــاء تبلـــغ إلـــىمـــن المـــواطنين فـــي محافظـــة النجـــف يتعرضـــون بعض أشهر السنة وخاصة أشهر الصيف وفتـرة تعـرض ال تقـل عـن من وقتهم في %) ٨٠(من ألكثرالمولدات ضــافة إلـى مصــادر الضوضــاء األخــرى والتــي مــن الممكــن أن باإل فــي أفضــل الحــاالت هــذا%) ٥٠(سـاعة ) ١٢( ٩٥(ة الــديزل حيــث وصــل مســتوى الضوضــاء لـــكمــا هــو الحــال فــي موقــع قيــاس مولــد تتــداخل مــع هــذا المصــدر هـي واحـدة مـن والكوفـة النجـف تيإن هذا المسـتوى مـن الضـجيج وفتـرة التعـرض الطويلـة تؤكـد أن مـدين. )ديسيبل .أكثر مدن العالم ضجيجا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٩ :تأثير ضجيج المولدات على الصحة العامة وت المولدات وفتـرة التعـرض فـانمن خالل الدراسات السابقة ومقارنة مستوى الضجيج الذي ينتج من ص يــؤدي إلــى ضــعف مســتديم فــي هــذا البحــث صــنف التلــوث بضوضــاء المولــدات علــى أنــه تلــوث اجتمــاعي مــزمن -:السمع باإلضافة إلى التأثيرات الصحية اآلتية القريبين من األشخاصديسيبل وتشمل ) ٨٠(فقدان السمع المؤقت عند التعرض لمستوى ضوضاء أعلى من . ١ .ى الضوضاء مثل مشغل المولدةمستو التأثير على انتظام ضربات القلب وضغط الدم والجهاز التنفسي. 2 االنزعاج وعدم الراحة النفسية وفقدان التركيز. ٣ باألرق اإلصابة. ٤ :معالجة وتقليل الضوضاء الناتجة عن صوت المولداتل المقترحات الالزمة -:لضوضاء الناتج عن صوت المولداتهناك عدة طرق لمعالجة وتقليل مصدر ا إخضــاع مولــدات الــديزل العامــة والشخصــية لضــوابط مديريــة حمايــة وتحســين البيئــة ومنــع أي مولــدة مــن -١ العمل بدون موافقة المديرية، تشريع قانون يمنع أصحاب الدور السكنية من تشغيل المولدات الشخصية التـي تعمـل بـالبنزين أو الـديزل -٢ لآلخرين،تثقيف المواطنين بضرورة توفير حياة هادئة بعد منتصف الليل و استبدال المصدر من خالل استخدام وسـائل توليـد طاقـة ال تسـبب الضوضـاء مثـل عاكسـات القـدرة التـي -٣ تســبب بطاريــة والخاليــا الشمســية ومحاولــة التــرويج الســتخدام مثــل هــذه المصــادر التــي ال التعمــل علــى تلوث ضوضائي، السكنية خالل فترة استراحة مولدات الشـارع أي بعـد منتصـف الليـل حتـى لألحياءربائية توفير الطاقة الكه -٤ إلى انتهائه، الظهيرة وبالنسبة لدوائر الدولة عند بداية الدوام الرسمي المصادر ، "التلوث الضوضائي طرق الحد منه: أخبار البيئة"، )٢٠٠٥(العيساوي، سليم نوري -١ www.4eco.com2005/01/2005.htme. ، )"الضوضاء(التلوث السمعـي : تلوث البيئة"، )٢٠٠٤(بدر الدين، محمد -٢ www.feedo.net/environment/environmentindex. ، "الضوضاء والسلوك: تلوث البيئة"، )٢٠٠٣(حسونة، جمال -٣ www.feedo.net/environment/environmentindex. .ar/003/001.htmwww.bafree.net/aftk، "التلوث الضوضائي"، )٢٠٠٧(حسين، علي -٤ .، جامعة الموصل"وتكنلوجيا البيئة علم"، )١٩٨٣(أحمد، طارق -٥ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٠ .www.arabic.sviva.gov.il/default.asp، "الضوضاء"، )٢٠٠٧(محمدي، زين الدين -٦ 7peirce, j. jeffry etal (1999), "environmental pollution and control", butterworth-heinemann, 5th edition, u )٢(. المستويات المسموح بها من الضوضاء في مناطق مختلفة داخل المدن: ) ١(جدول المنطقة )درجة هيرتز(مستوى الضوضاء مناطق المستشفيات ٣٥ – ٢٠ المناطق السكنية ٤٠ – ٢٥ المناطق التجارية ٦٠ – ٣٠ المناطق الصناعية ٦٠ – ٤٠ المناطق التعليمية ٤٠ – ٣٠ )٥(. بوحدة الديسيبل األصواتمستوى قياس بعض ) : ٢(جدول )ديسيبل(مستوى ضغط الصوت نوع الصوت ٢٠ – ١٠ الهمس ٤٠ – ٣٠ الموسيقى الهادية ٧٠ – ٦٠ الشوارع المزدحمة ٨٠ – ٧٠ سيارة صغيرة ٩٠ – ٨٠ سيارة شحن ١٠٠ – ٩٠ األنفاققطار ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩١ ١٣٠ – ١١٠ طائرة عند اإلقالع فما فوق ١٢٠ حد األلم )٧(. مستويات ضغط الصوت للمحادثة بين شخصين) : ٣(جدول المسافة )قدم( )ديسيبل(مستوى الحديث صراخ حديث عادي ٧٨ ٦٠ ٣ ٧٢ ٥٤ ٦ ٦٦ ٤٨ ١٢ )٥،٧(. ا في جو العملفترات التعرض القياسية للضوضاء المسموح به) : ٤( جدول مستوى الصوت db (a) فترة التعرض )ساعة( ٨ ٩٠ ٦ ٩٢ ٤ ٩٥ ٣ ٩٧ ٢ ١٠٠ ١.٥ ١٠٢ ١.٠ ١٠٥ ٠.٥ ١١٠ ٠.٢٥ ١١٥ )٥( .معايير مستوى الصوت المسموح بها في بعض المنشات خالل ساعات النهار والليل) ٥( جدول l50 l20 نهارا ليال نهارا ليال الموقع ٥١ ٤٦ ٤٥ ٤٠ منطقة سكنية ٤٦ ٤٦ ٤٠ ٤٠ مدرسة ٤٦ ٤١ ٤٠ ٣٥ مستشفى ٥٦ ٥٦ ٥٠ ٥٠ دوائر ٤٦ ٤٦ ٤٠ ٤٠ مسارح ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٢ ٥٦ ٥١ ٥٠ ٤٥ فنادق )٧(.من مصدر للضوضاء على المحصلة النهائية لها أكثرمنحني اليجاد تأثير ) ١(شكل صادر الضوضاء في محافظة النجف ا1شرفاستبيان عن أھم ماستمارة :ا1سم : العمر :الحالة ا9جتماعية :المھنة :عنوان السكن ما ھي أھم مصادر الضوضاء والضجيج في مدينتك؟ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٣ في العراقعلى التربة والبيئة الكيمياوية األسمدةاثر صناعة غازي مالح مطر. د. م.أ المستنصرية الجامعة/كلية الهندسة الخالصة بعد ستينات. التاسع عشر القرن نتصفالكيماوية وتستعمل بشكل واسع عالميا منذ م األسمدةتصنع عدد من تاخذوالرتفاع اسعار االسمدة الكيماوية المستوردة وكنتيجة لزيادة الطلب على الغذاء القرن الماضي ضوضاء المولدات ضوضاء المركبات ضوضاء المدارس ضوضاء ساحات اللعب ضوضاء الك�ب السائبة ضوضاء ا�سواق الشعبية .والكوفة سم توضيحي يبين نسب مصادر الضوضاء في أحياء مدينتي النجفر ) ٣(شكل 5-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 a numerical study of natural convection heat transfer inside a horizontal square enclosure with a concentric heated rod and a bundle of triangular heated cylinders rana l. natoosh mechanical engineering department college of engineering basra university abstract: in this paper, a numerical investigation of steady laminar natural convection in a square enclosure, contain a concentric heated rod and a bundle of four triangular heated cylinders was carried out. two cases of enclosure inclination angle were studied: case (i) at =0o and case (ii) at =45o. air is filled the enclosure, and the inner heated cylinders are located at equal distance (e) from the enclosure center. a finite element software package (flexpde) is used in the present study to solve the set of non-linear equations governing the process. solutions are obtained for aspect ratio h/h=0.29, a values of distance e=0.27-0.44 and a range of rayleigh number 103 105. the effect of ra, e and were examined. results are presented by streamlines, isotherms and nusselt number and they indicates that the nusselt number is significantly increases with increasing ra, e and . a comparison of the streamlines, isotherms and mean nusselt number was made with that obtained by other authors, which it reveals a good agreement. keywords: natural convection; square enclosure; triangular heated cylinders; uniform wall temperature جامعة -ت ة ".مسخنة ،=0o=45o . (e) . )(flexpde. لنسبة h/h=0.29 ،e=0.27-0.44 103 105 .، al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 . e ، ra مع" .مع nomenclature greek symbols thermal diffusivity (m2/s) thermal expansion coefficient (1/k) ɛ the distance between the center of enclosure and the center of inner circular cylinder dimensionless temperature dynamic viscosity (n/m2.s) kinematics viscosity (m2/s) fluid density (kg/m3) the angle of inclination of the enclosure stream function subscripts i inner l local m mean o outer d diameter of circler rod (m) e the distance between the center of enclosure and triangular base g gravitational acceleration (m/s2) h height of triangle (m) h height of square enclosure (m) nul local nusselt number num mean nusselt number p,p pressure, dimensional(n/m2) and dimensionless pr prandtl number ra rayliegh number rr ratio of l/2ri s dimensionless local coordinate t temperature (k) u, u dimensional and dimensionless horizontal velocity component v, v dimensional and dimensionless velocity component x,y non-dimensional coordinates 1. introduction the phenomenon of natural convection in enclosures has received considerable attention in recent years. this attention is mainly because this phenomenon often affects the thermal performance in many engineering and science applications such as boilers, nuclear reactor systems, energy storage and conservation, fire control and chemical, food and metallurgical industries. in engineering applications, the geometries that arise however are more complicated than a simple enclosure filled with a convective fluid. a large number of literature is available which deal with the study of natural convection in enclosures with either vertical (khaled and bhattacharyy, 2006), inclined (venkateswara et al.,2006), (yasin et al., 2008) or horizontal (natarajan et al, 2008), (tanmay et al., 2009) imposed temperature difference. (tanmay et al., 2009) reported the numerical results of natural convection in trapezoidal enclosures for uniformly heated bottom wall, linearly heated vertical wall and of insulated top wall. parametric studies for the wide range of rayleigh numbers ra (103-105) and prandtl numbers pr (0.7 -1000) with va have been performed. it was found that, higher heat transfer rates for =0 and the overall heat transfer rates at the bottom wall were larger for the linearly heated left wall and cooled right wall. (patrick and jane, 2005) using an iterative, semi-implicit finite-difference method to solve the governing unsteady, threedimensional free convective flow equations in a rectangular enclosure. the enclosure considered had rectangular horizontal lower and upper surfaces and vertical side surfaces and there were two square isothermal heated sections on the lower surface, the rest of this surface being adiabatic. (kim et al.2008) studied the examine how the position of the inner circular cylinder relative to the outer square cylinder affects the natural convection phenomena for different rayleigh numbers ( al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 103 106 ) when a hot inner circular cylinder was located at different positions along the vertical centerline of the outer square cylinder. (kumar and dalal, 2006) considered the problem of natural convection around a square, horizontal, heated cylinder placed inside an enclosure in the range of 103 106. effects of the enclosure geometry have been assessed using three different aspect ratios placing the square cylinder at different heights from the bottom. (shu et al., 2001) numerically studied natural convection between an outer square enclosure and an inner circular cylinder according to the eccentricity and angular position of the inner circular cylinder at a rayleigh number of 3*105. it was found that the global circulation, flow separation and the top space between the square outer enclosure and the circular inner cylinder have significant effects on the plume inclination. laminar convection heat transfer from a horizontal triangular cylinder to its concentric cylindrical enclosure has been numerically studied by (zi-tao et al., 2010), to investigate the prandtl number effect on flow and heat transfer characteristics. they found that the flow and heat transfer characteristics for a low prandtl number fluid (pr = 0.03) were unique and they were almost independent of prandtl number when pr 0.7. a numerical investigation of steady-state laminar natural convective heat transfer around a horizontal cylinder to its concentric triangular enclosure was studied by (xu xu et al., 2010). the enclosure was filled with air and both the inner and outer cylinders were maintained at uniform temperatures. at the highest rayleigh number studied, the effects of different inclination angles of the enclosure and various cross-section geometries of the inner cylinder were investigated. the computed results indicated that at constant aspect ratio, both the inclination angle and cross-section geometry have insignificant effects on the overall heat transfer rates though the flow patterns are significantly modified. e. (fuad, 2009) presented a numerical analysis of laminar natural convection in an enclosure of isosceles triangular cross-section has been performed for cold base and hot inclined walls. base angles varying from 15 to 75 have been used for different rayleigh numbers ranging from 103 to 105. it was observed that the enclosures with a low aspect ratio have higher heat transfer rates from the bottom surface of the triangular enclosure. (tanmay basak et al., 2008) used a finite element analysis with bi-quadratic elements to investigate the effects of uniform and non-uniform heating of inclined walls on natural convection flows within a isosceles triangular enclosure. the numerical solution of the problem was presented for various rayleigh numbers (ra), (103 ra 106) and prandtl numbers (pr), (0.026 pr 1000. a survey of literature reveals that multi-inner triangular cylinders that are inside air-filled square enclosure has not been investigated. this is the motivation of the present study where a bundle of four triangular heated cylinders with concentric heated rod inside a square enclosure is to be studied. the effect of rayleigh number, inclination angle of the enclosure and the distance between the center of enclosure and triangular cylinders on the flow and thermal fields for constant aspect ratio are studied in detail 2. governing equations a schematic of the two systems considered in the present study are shown in fig.1. a case (i) (fig.1a) consists a square enclosure ( =0o) while case (ii) (fig.1 b) consists a tilted square enclosure with =45o. for two cases a square enclosure contains the concentric rod and four triangular cylinders located at equal distances e from the center of enclosure. the temperature of inner cylinders is higher than that of the square walls and both are uniform. the origin of the cartesian coordinates (x, y) is positioned at a square center. the aspect ratios h/h=0.29 and d/h=0.24, the range of rayliegh number 103 105, the locations of the inner cylinder 0.27 0.44 and pr=0.71 were considered in this study. the fluid is assumed to have constant physical properties but obeys the bussinesq approximation according to which the compressibility effect every where is neglected except for buoyancy force term. viscous dissipation and heat generation are absent. hence, the two-dimensional, incompressible, steady state dimensionless governing equations using conservation of mass, momentum and energy can be written as (xu xu et al., 2010): al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 (1)0 y v x u (2)2 2 2 2 y u x u x p y v v x u u (3) pr2 2 2 2 ra y v x v y p y v v x v u (4) 2 2 2 2 pr 1 yxy v x u non-dimensional parameters can be given as follows: 2 2 ,,,,, v hgyp p tt ttvh v uh u h y y h x x oi o 3httg ra oi, and rayleigh numberpr prandtl number 3. numerical solution it is well known in the numerical solution field that the set of equations (eqs. (1) to (3)) may be highly oscillatory or even sometimes undetermined because of inclusion of the pressure term in the momentum equations. in the present study, a finite element software package (flexpde) (backstrom, 2005) is relied on in solution of the nonlinear system of equations. in finite element method there is a derived approach with purpose of stabilizing pressure oscillations and allowing standard grids and elements. this approach enforces the continuity equation and the pressure to give the following, what called penalty approach (langtangen, 2002) y v x u p2 (5) where λ is a parameter that should be chosen either from physical knowledge or by other means (langtangen, 2002). a most convenient value for was attained in this study to be 1e8 /h2 . hence, the continuity equation (1) is excluded from solution system and replaced by equation (5). the numerical solutions are obtained in terms of velocity components (u,v) and the stream components (u,v) as (tanmay et al., 2007): x v y u yx 2 2 2 2 (6) -clockwise circulation and the clock wise the heat transfer coefficient in terms of the local nusselt number nul along the inner cylinders surface and the outer wall is defined by (tanmay et al., 2007): al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 (7) n nul where n is the normal direction on a plane. at steadystate it is obvious that the mean nusselt numbers along both the inner and outer walls are exactly identical. hence, the average nusselt number can be evaluated along the outer wall as: (8)ol soo m dsuns nu 1 the appropriate boundary conditions are as follows isothermal surfaces i.e. =1 on the concentric rod and triangular cylinders walls and =0 on the square walls. -no-slip velocity boundary condition, u=v=0 on all solid walls. -pressure gradient normal to all surfaces is zero, 0 n p where n is a normal unit vector. 4. validation 4.1 software validation to check the validation of software, the grid dependency and the distribution values of ( + / ) over the domain ra=103 and e=0.36 with accuracy 10-4 are presented in fig.2, a and b. it is clear that the continuity equation is exactly validated, where it as mentioned in section 3, do not contribute in solving the governing equations. 4.2 validation of numerical results for the purpose of code validation, the natural convection problem for a low temperature outer square enclosure and high temperature inner circular cylinder (ra=3*105 , pr=0.71, (rr = l/2ri) equal to 2.6 (where l: side length of the square outer cylinder, ri: radius of the inner cylinder) and the distance from the center of enclosure to the center of the inner cylinder ɛ =0, 0.25 and 0.5) was tested. the streamlines and isothermal patterns at ɛ =0.25 for present result are compared with the (she et al., 2001), see fig.3. the results of the present work shows a good agreement with those of ref. (she et al., 2001). the calculated mean nusselt number num along the outer wall between the present work and the work of ref.(she et al., 2001) is compared for ɛ =0, 0.25 and 0.5 as shown in table (1) . the num are in good agreement with the values of (she et al., 2001). 5. results and discussion in the present study the effect of the rayleigh number and the locations of the inner triangular cylinders were systematically investigated for two different cases of the square enclosure. the basic features of flow and heat transfer are analyzed with the help of isotherm and the streamline patterns. local and average nusselt numbers on the isothermal surfaces are plotted to evaluate the local and overall heat transfer process. 5.1 analysis of flow and thermal fields for all rayleigh numbers at each case considered in this study, the flow and thermal fields are symmetric shape about the vertical centerline through the center of the concentric circular rod. in other words, the governing equations given in eqs (1) to (4) and the boundary conditions are invariant to the following transformation: symmetry about x =0 : { u,v,θ,x,y} { -u,v,θ,-x,y} (9) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۰ 5.1.1 flow and thermal fields when e=0.36 the results of flow fields and isotherms for air flow in a square with heated inner cylinders at e=0.36 are examined in this section. fig.4 shows streamlines (on the left) and isotherms (on the right) for different values of ra in case(i) (φ=0). at low ra (ra=103), as shown in the left side in fig.4a, six circulation cells of streamlines are formed inside the enclosure. two of them are the strongest and localized in the space between each two triangular cylinders near the vertical walls. the others are smaller and located around a concentric rod. this formula of circulations are appear due to the buoyant effects which are caused by the temperature difference between the inner and outer walls, and this lead to form the recirculation vortices which are clearly demonstrated by the closed streamlines. at ra=3*104, as shown in the left side of fig.4b, it can be seen that the upper and lower cells around concentric rod merge together and a new cell is formed near each corner of the enclosure. as ra increases to 105(fig.4c on left), the cells in the upper two corners begin to merge with the two strong cells while two small new cells appears near the upper part of concentric rod when the old two cells begin to move down . the effect of buoyancy force become stronger compared to viscous forces and the intensity of fluid motion has been increased as indicated by relatively larger magnitudes of stream functions. the thermal fields are presented in the form of isotherms in the right side of fig.4. at ra=103(fig.4a), the heat transfer in the enclosure is mainly dominated by the conduction mode therefore, we can observe that four equivalent like plumes distribution start to appears from the space between each two inner triangular cylinders towards the center of enclosure. with increasing of rayliegh number (ra=3*104) as shown in fig.4b, the upper plume vanish gradually while the lower plum start to growth toward the center of enclosure. as the rayleigh number increases up to 105, the role of convection in heat transfer becomes more significant, consequently the upper plum disappear while the lower and both side plumes rise upward , giving rise to a stronger thermal gradient in the upper part of the enclosure. fig.5 shows streamlines (on the left) and isotherms (on the right) for different values of ra in case (ii) (φ=45). at low ra (ra=103) ,as in case(i), there are many circulation cells formed inside the enclosure and the number of cells here is larger than in case(i) , this is because of the inclination of the enclosure that leads to increase of the secondary flow. two small circulation cells localized in the space between each triangular cylinder side and enclosure corners, another two cells appears at each side of the concentric rod. the last four circulation cells are more in strength and localized in the space between each two inner triangular cylinders. with increasing of rayleigh number (ra=3*104and ra=105),as shown in fig.5b and c, the size of the small cells are growth and the two cells near the concentric rod start to move upward, also the two cells that are in the upper part of the enclosure slightly becomes smaller in size and weaker in strength compared with those in lower part of it. as in case(i), the strength of cells become more at high rayleigh numbers compared with the lower values of it, due to increase the buoyancy effect and dominant of free convection heat transfer. the behavior of thermal patterns in this case is similar to that in case (i) especially at ra=103, as shown the right side in fig.5. at ra=3*104 we can observe in fig.5b that the size of each upper like plum distribution is vanish gradually with increasing of rayleigh number. for high rayleigh number (ra=105 )as shown in fig.5c(right), the lower plumes start to growth to upward and merge with the upper plumes due to reducing the density of fluid which lead to growth the thermal boundary layer. 5.1.2 flow and temperature fields as a function of e:the dependence of the flow and thermal fields on the location of inner heated triangular cylinders can be observed in the plots of the streamlines and isotherms for three different values of e (0.27, 0.36, 0.44) at ra = 3*104 and φ=0 (case(i)) as shown in fig.6. it can be seen from the left side of this figure that the number of circulation cells decreases with increasing the value of e while the size of each cells increases with increasing of e. this is because a greater space is then available al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۱ for the cells to be larger when e increases. it is also noticed that the strength of cells increases with increasing of e. the right side of fig.6 shows that the upper like plum distribution is vanish at lower values of e (e=0.27) while the size of each plum increases with increasing of e due to the increasing the growth of the thermal boundary layer 5.2 heat transfer rates: local and mean nusselt numbers 5.2.1 local nusselt numbers figs.7 and 8 display the effects of ra on the local nusselt number along the circumference of inner triangular cylinders and outer enclosure wall for e=0.36 in case (i) and case (ii) respectively. variation of the local nusselt number along the upper left inner triangular cylinder at φ=0 for different rayleigh numbers is plotted in fig.7-a. as can be seen from this figure that, at ra=103 the local nusselt number (nul) has a maximum value at s1=0, which represent the point on the upper left corner of the triangular, then the nul decreases until s1=0.11, and it remain constant to the distance s1=0.22, then the nul increases until s1=0.29, which represent the point on the lower corner of the triangular cylinder. when we move along the inclined wall of the triangular cylinder, the value of nul decreases, and reaches a minimum at s1=0.5, then increases toward the upper right corner at s1=0.71. then the turned of curve of nul along the horizontal surface of triangle (0.71≤ s1≤1) is the same as that of vertical wall. the shape of the local nusselt number distribution at ra =3*104 is generally similar to that at ra=103. at high rayleigh number (ra=105), the distribution is different along the inclined and horizontal walls of the triangular cylinder. the values of nul increases with increasing of ra along the portion 0.3≤s1≤0.62 and decreases otherwise. this is due to the like plum distribution of the isotherms through the space between the heated cylinders (which is shown in fig.4) is greatly spread at high ra due to the increase the strength of streamlines. the maximum values of nul appear on the corners of the triangular cylinder, due to the growth of thermal boundary layer near the corners and that's lead to dominant the convection instead of conduction near to these regions. fig7-b shows the distribution of local nusselt numbers along the lower left inner triangular cylinder for different rayleigh numbers. the curves have a similar ushape at each wall of the triangle. the value of nul has a relatively small variation with increasing of ra along the vertical and inclined walls of the triangular cylinder while it increases with increasing of ra along the horizontal wall. the higher values of nul appears at the vertical and horizontal walls due to the dominant of convection near to these regions, while the values of nul are lower at the inclined wall of triangular cylinder due to the dominant of conduction. the distribution of nul along the concentric rod for the same parameters above is shown in fig.7-c. at ra = 103, the distribution of nul show almost a symmetric shape with respect to the horizontal centerline at y = 0 due to the symmetric distribution of isotherms. the variation of nul is very small and increases with increasing ra. with increasing of rayleigh number (ra=3*104 and 105) the distribution of nul is not symmetric any more with respect to horizontal due to the effect of convection. also we can observe that the maximum value of nul appears at si=0.5 while the minimum values at the upper point of cylinder (si=0 or si=1) .the maximum value of local nusselt number increases with increasing ra because the like plumes distribution growth upward in the presence of convection, meaning that the nul at the lower surface of the concentric rod is larger than that at the upper surface of it. variations of the local nusselt number along the outer enclosure wall are plotted in fig.7-d for the same above parameters. the curves have a similar sinusoidal distribution with m-shape at the distance which represents the base and each vertical side of the square enclosure. the distribution of nul at the upper surface of enclosure changes with increasing of ra. at ra=103 the nul on the upper wall have the same behavior while when ra increases to 105, the behavior of nul is completely different having sinusoidal distribution with very high values of nul. this different due to the growth the plumes to upward as shown in fig.4(on left), and as a result the values of local nusselt number along the upper part of enclosure wall (0 ≤ so≤ 0.125 and 0.625 ≤ so≤ 1) is larger than that at the lower part of it (so=0.125-0.625). al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۲ fig. 8-a shows the distribution of local nusselt numbers along the hot surface of the upper triangular cylinder for different ra and φ=45o. the distribution of nul shows symmetrical shape with respect to the vertical centerline due to the symmetric shape distribution of flow and thermal fields. the distribution of nul in this case is similar to that along the upper left triangular cylinder in case (i) , especially at lower values of ra. also it can be seen that the values of nul decreases with increasing of ra except along the portion that represents the bottom wall of the triangular cylinder (0.29≤ s1 ≤0.71). the maximum values of local nusselt numbers appears at the upper corner of the triangle (s1=0 or s1=1) while the minimum values appears at s1=0.5 due to the growth of the thermal boundary layer and dominant convection heat transfer near the upper corner while the conduction heat transfer is the dominant near the bottom wall of the triangular cylinder (as showed in fig.5). the variation of local nusselt numbers along the hot surface of the left triangular cylinder for different ra are shown in fig.8-b. it can be seen that the nul is increases with increasing ra along the lower inclined and the vertical walls of the triangular cylinder (0.29≤ s2 ≤0.96), while vise versa for the upper inclined wall. the lower values of nul appears at the vertical wall due to dominant the conduction near the center of enclosure, while the values of nul are higher at the lower inclined wall of triangular cylinder due to dominant of the convection. the distribution of local nusselt numbers along the hot surface of the lower triangular cylinder for different ra are shown in fig.8-c. the distribution of nul is similar to that along the lower left cylinder in case(i). the value of nul increases with increasing of ra along the left and right inclined walls of the triangular cylinder due to increasing the effect of convection, while it has a relatively small variation with increasing of ra along the horizontal wall. the maximum value of nul is located on the corner of triangular cylinder that is near the enclosure corner at ra=103 and ra=3*104. at ra=105, the maximum values of nul are located on each upper corner of triangular cylinder, because the isotherms are symmetric shape with respect to the vertical centerline at x = 0 as shown in fig.5(left). variation of the local nusselt number along the concentric rod for the same above parameters is plotted in fig.8-d. at ra=103,as in case(i), the distribution of nul show almost a symmetric shape with respect to the horizontal centerline at y=0 because the dominant effect is conduction. the other curves show two peaks with equal altitude at the left and right sides of the lower part of cylinder. the local nusselt number increases with increasing ra except along the upper part of the cylinder because, as previous mentioned, the lower plumes start to growth to upward in the presence of convection as shown in the left side of fig.5 .the maximum values of nul, for ra=3*104 and ra=105, appears at si=0.37 and si=0.63 while the minimum values of rayleigh number 103≤ra≤105, appears at the upper point of concentric rod (si=0 or si=1). fig.8-e shows the distribution of local nusselt number along the outer enclosure wall for the same above parameters. for ra=103 and 3*104, the distribution exhibits the same form to that along the outer enclosure wall in case (i). at high rayleigh number (ra=105), the distribution of nul along each the lower inclined walls of the square enclosure have the same behavior, while the behavior of nul along each the upper inclined walls have sinusoidal distribution with very high values of nul. this can be demonstrated by the steep temperature gradient along the upper inclined walls of enclosure as in fig.5c right. 5.2.2 mean nusselt numbers the mean nusselt number is utilized to represent the overall heat transfer rate within the domain interest. fig.9a and b shows the mean nusselt number of the enclosure as a function of the distance (e) with different rayleigh numbers for case (i) and case (ii) respectively. it can be seen that the mean nusslet number ,for each case, depends on the variation of the distance (e) and increases with increasing e, due to increasing the thermal gradient with decreasing the space between the inner cylinders and the wall of the outer enclosure as shown in fig.6 (right). also we can observe from this figure that for each value of e the value of mean nusselt numbers is increased with ra due to dominant the convection heat transfer, and this value of increasing is greater in case(ii) than in case(i) for ra≥104 as illustrated more in fig.10. the change of mean nusselt numbers, at the outer enclosure, versus ra with different (e) for each case is presents in fig.10. it can be seen that, al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۳ for e=0.27 and e=0.36 the num is a strongly effected by high various of rayliegh number especially in case(ii) due to the growth of thermal boundary layer and enhancing the heat transfer coefficient. also for e=0.44 we can observe that a small variation of num with increasing of rayleigh number. 6. conclusions in the present paper, a numerical investigation of steady laminar natural convection in a square enclosure contain a concentric heated rod and a bundle of 4-trainguler heated cylinders was studied in two cases depending on various inclined angle of the enclosure (φ=0o and φ=45o). a detailed analysis for the distribution of streamlines, isotherms and nusselt number was carried out to investigate the effect of the locations of the heated inner cylinders on the fluid flow and heat transfer in the square enclosure for different rayleigh numbers in the range of 103 ≤ ra ≤105. the conclusions can be drawn as follows: 1. flow fields and isotherms are strongly affected by changing rayleigh number, the location of inner cylinders (e), and the angle of inclination of the enclosure (φ). 2. the values of local nusselt number along the upper part of outer enclosure wall are larger than that at the lower part of it. 3.the mean nusselt number and the intensity of stream are an increasing function to rayliegh number. 4. location of the inner heated cylinders play an important role to enhance the over all heat transfer significantly. 5. the values of num in inclined square enclosure at φ=45o are larger than in enclosure at φ=0o. references -backstrom gunnar, (2005) "fields of physics by finite element analysis using flexpde" by gb publishing and gunnar backstrom malmo. fuad kent e.,(2009) "numerical analysis of laminar natural convection in isosceles triangular enclosures for cold base and hot inclined walls" mechanics research communications 36, 497– 508. -khaled khodary , bhattacharyy, t.k., (2006) "optimum natural convection from square cylinder in vertical channel" international journal of heat and fluid flow 27, 167–180 kim b.s. , lee d.s., ha m.y. ,yoon h.s., (2008) "a numerical study of natural convection in a square enclosure with a circular cylinder at different vertical locations" international journal of heat and mass transfer 51, 1888–1906. kumar de a., dalal a., (2006) "a numerical study of natural convection around a square, horizontal, heated cylinder placed in an enclosure "int. j. heat mass transfer 49, 4608–4623. -langtangen h.p., mardal k.a. and winther r., (2002) " numerical methods for incompressible viscous flow" advances in water resources 25 1125–1146. natarajan e., tanmay basak, roy s.,(2008) "natural convection flows in a trapezoidal enclosure with uniform and non-uniform heating of bottom wall" international journal of heat and mass transfer 51, 747–756. patrick h. oosthuizen , jane t. paul, (2005) "natural convection in a rectangular enclosure with two heated sections on the lower surface"international journal of heat and fluid flow 26, 587– 596. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲٤ shu c., xue h., zhu y.d.,(2001) "numerical study of natural convection in an eccentric annulus between a square outer cylinder and a circular inner cylinder using dq method" int. j. heat mass transfer, 44, 3321–3333. -tanmay basak, roy s., amit singh, bishun d. pandey, (2009) "natural convection flow simulation for various angles in a trapezoidal enclosure with linearly heated side wall(s)" international journal of heat and mass transfer 52, 4413–4425. tanmay basak, roy s., krishna babu s., balakrishnan a.r., (2008) "finite element analysis of natural convection flow in a isosceles triangular enclosure due to uniform and non-uniform heating at the side walls" international journal of heat and mass transfer 51, 4496–4505. tanmay basak, roy s., thirumaleshaa ch., (2007) " finite element analysis of natural convection in a triangular enclosure: effects of various thermal boundary conditions" chemical engineering science 62, 2623 – 2640 venkateswara rao m., pv ravi kumar&psi sankara rao , (2006) "laminar flow heat transfer in concentric equilateral triangular annular channel", indian journal of chemical technology vol.13, pp.614-622. xu xu , zitao yu , yacai hub, liwu fan , kefa cen, (2010) "a numerical study of laminar natural convective heat transfer around a horizontal cylinder inside a concentric air-filled triangular enclosure" international journal of heat and mass transfer" international journal of heat and mass transfer 53, 345–355. yasin varol, hakan f. oztop and ioan pop, (2008) "numerical analysis of natural convection in an inclined trapezoidal enclosure filled with a porous medium" international journal of thermal sciences 47, 1316–1331. -zi-tao yu, li-wu fan , ya-cai hua, ke-fa cen,(2010) "prandtl number dependence of laminar natural convection heat transfer in a horizontal cylindrical enclosure with an inner coaxial triangular cylinder" international journal of heat and mass transfer 53, 1333–1340. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲٥ fig.1 schematic diagrams of the physical domain a) case(i) b) case(ii) -b--ah so s2 h s1 si e so s1 s2 s3 si φ=45o e fig.2 (a) grid distribution over the domain ( b) validation of continuity equation -a-bal-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲٦ table (1) comparison of num between the present work and the work of (shu et al., 2001) for ra=3*105, pr=0.71 and rr=2.6 0.5 6.95 6.98 0.43 0.25 6.75 0.9036.689 num (present) num (shu et al., 2001) error %ɛ 6.526.6 1.20 fig.3 comparison of streamlines and isotherms with (shu et al., 2001) for ra=3*105, pr=.71, and rr=2.6 shu et al.(2001) streamlines isotherms present work isothermsstreamlines al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۷ fig.4 streamlines (left) isotherms (right) for case(i) a)ra=103 b)ra=3*104 c) ra=105 a b c al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۸ fig.5 streamlines (left) isotherms(right) for case(ii) a)ra=103 b)ra=3*104 c) ra=105 a b c al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۲۹ a fig.6 streamlines(left) and isotherms (right) for case(i) and ra=3*104 a)e=0.27 b)e=0.36 c)e=0.44 b c al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۰ fig.7 variation of the local nusselt number for case(i) along the a) upper left triangular cylinder b) lower left triangular cylinder c)concentric circular rod d)outer enclosure, at e=0.36 -a-bdistance,s1 distance,s2 nul 0 5 10 15 20 25 0 0.2 0.4 0.6 0.8 1 ra = 1 0 0 0 ra = 3 0 0 0 0 ra = 1 0 0 0 0 0 nul 0 1 0 2 0 3 0 4 0 0 0 .2 0 .4 0 .6 0 .8 1 r a= 1 0 0 0 r a= 3 0 0 0 0 r a= 1 0 0 0 0 0 -c-ddistance, si distance, so 0 5 10 15 20 25 0 0.2 0.4 0.6 0.8 1 ra=1000 ra=30000 ra=100000 nul 0 2 4 6 8 0 0.2 0.4 0.6 0.8 1 ra=1000 ra=30000 ra=100000 nul al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۱ fig.8 variation of the local nusselt number for case(ii) along the a) upper triangular cylinder b) left triangular cylinder c)lower triangular cylinder d) concentric circular rod e) outer enclosure, at e=0.36 -enul distance ,so 0 5 10 15 20 25 0 0.2 0.4 0.6 0.8 1 ra=1000 ra=40000 ra=100000 -a-bnul 0 5 10 15 20 25 0 0.2 0.4 0.6 0.8 1 dist ance ra=1000 ra=30000 ra=100000 0 5 10 15 20 25 30 0 0.2 0.4 0.6 0.8 1 distance ra=1000 ra=30000 ra=100000 nul distance ,s1 distance ,s2 -c-dnul 0 1 0 2 0 3 0 4 0 0 0 .2 0 .4 0 .6 0 .8 1 dist a n c e r a = 1 0 0 0 r a = 3 0 0 0 0 r a = 1 0 0 0 0 0 0 2 4 6 8 0 0.2 0.4 0.6 0.8 1 distance ra=1000 ra=30000 ra=100000 nul distance ,s3 distance ,si al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۲ fig.9 variation of the mean nusselt number with e along the outer wall for different rayleigh number a) case(i) b) case(ii) -a-be e num 0 4 8 12 16 20 0 .2 5 0 .3 0 .3 5 0 .4 0 .4 5 ra=1 0 0 0 ra=3 0 0 0 0 ra=7 0 0 0 0 ra=1 0 0 0 0 0 num 0 4 8 1 2 1 6 2 0 0 .2 5 0 .3 0 .3 5 0 .4 0 .4 5 ra =1 0 0 0 ra =3 0 0 0 0 ra =7 0 0 0 0 ra =1 0 0 0 0 0 fig.10 variation of the mean nusselt number with rayleigh number along the outer wall for different values of e ra num 0 4 8 1 2 1 6 2 0 1 0 0 0 2 1 0 0 0 4 1 0 0 0 6 1 0 0 0 8 1 0 0 0 1 0 1 0 0 0 1 2 1 0 0 0 e =0 .2 7 e =0 .3 6 e =0 .4 4 e =0 .2 7 e =0 .3 6 e =0 .4 4 case(i) ---- case(ii) case(i) case(ii) template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 226 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. analysis and simulation of a triple-stage series flow absorption chiller cycle for air conditioning applications qusay rasheed al-amir, department of mechanical engineering, babylon university, hilla, iraq email: qusay1972@gmail.com received on 25 january 2017 accepted on 6 april 2017 abstract: this paper represents a numerical study of a triple-stage series flow absorption cycle operating with libr-h2o pair. a computational model is implemented using engineering equation solver (ees) software. this model includes equations of mass, species and energy conservation. the analysis is used to simulate a triple stage absorption chiller utilization for an air conditioning applications with a nominal capacity of 300kw manufactured by thermax company. this chiller is indirect fired type which uses steam from boiler of the hpg as heat source. the variations of performance parameters with different ranges of operation conditions have been calculated. the operating parameters are selected as follows: the hpg, mpg and lpg temperatures: thpg= 150230°c, tmpg= 100-130°c and tlpg= 60-95°c, respectively, lpc temperature tlpc= 28-37°c, evaporator temperature tevap = 5-14°c; flow rate of refrigerant mr= 1 kg/s; four values of heat exchangers effectiveness 0.4, 0.5, 0.6 and 0.65. in addition, the comparison between the present study and other study obtained in literature review has been done. the analysis revealed that maximum cop is found as a function of both mpg and lpg temperatures. the results outline that the cop increases with an increase in the evaporator and generators temperature but decreases with condenser temperature. keywords: triple-stage libr-h2o absorption cycle, ees software, cop, thermodynamic analysis. nomenclature o outlet c specific heat capacity (kj/kg.k) s strong solution h enthalpy [kj/kg] r refrigerant m mass flow rate [kg/s] w weak solution p pressure(kpa) abbreviations q heat transfer rate(kw) cop coefficient of performance t temperature (c) ees engineering equation solver f circulation ratio(-) he heat exchanger w work (kw) h2o water x species concentration hpc high-pressure condenser greek symbols hpg high-pressure generator ϵ effectiveness libr lithium bromide subscripts lpc low-pressure condenser a absorber lpg low-pressure generator mailto:qusay1972@gmail.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 227 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. c condenser mpc middle-pressure condenser e evaporator mpg middle-pressure generator g generator shx solution heat exchanger in inlet tv expansion valve 1. introduction and overview the absorption refrigeration is investigated as one of environmentally friendly refrigeration technologies. this technology depends on heat instead of electricity to produce cooling load which is employed for air conditioning purposes or ice making. however, absorption system required to auxiliary accessories to work with high efficiency such as cooling tower to cool the refrigerant in both the condenser and absorber, and low grade heat sources to heat the generator to increase the system performance. many and various energy sources are used in absorption systems such as solar energy, geothermal, biomass and waste heat from the fossil fuel combustion in industries or power plants. absorption chillers utilize a refrigerant–absorbent pair as a working fluid such as water-ammonia, lithium chloride-water, lithium bromide-water and lithium nitrate-ammonia. the most common conventional fluids using for absorption chillers for both cooling and heating applications are water-ammonia and lithium bromide-water due to their have the desirable properties than the other fluids. the absorption chiller also is a closed loop cycle which can be classified into five types such as half-stage, single-stage, double-stage, triple-stage and multi-stage. the single-stage and half-stage chillers operate using low temperature hot water with respect to a double-stage, triple-stage and multi-stage chillers (chidambaram et al,. 2011). the cycle performance improves more with increasing number of stages but it requires higher temperature waste heat (greater 175c) and extra components. in addition to above, there are also two other absorption chillers which are diffusion absorption and hybrid chillers. these systems give better performance (ullah et al., 2013). several theoretical studies in this field are done on the single-stage ( sencan et al., 2005, aphornratana and sriveerakul, 2007, kim et al., 2009, bahman, 2011, and ha, 2013) and double-stage cycles (misra et al., 2005, figueredo et al. 2008, kaushik and arora, 2009, marcos et al., 2011 ). for instance, saghiruddin and siddiqui, 2001 conducted economic analysis and thermodynamic of the single effect absorption cycle. they used various working fluid in their analysis such as nh3-h2o, libr-h2o, nh3lino3 and nh3-nascn and different sources of energy such as solar collectors, lpg and biogas. grossman and zaltash, 2001 have made a computer absim code for the flexible and modular form simulation of a single-effect absorption schemes with different working fluids. joudi and lafta, 2001 offered a computational model to describe the influence of several operating cases on the function of each component and to find the single-effect absorption refrigeration system performance working on libr–h2o solution. florides et al., 2003 formed a mathematical model based on balance of mass and energy equations written for each components of absorption cycle with 1 kw cooling capacity. mehrabian and shahbeik, 2005 developed the computer study for a single-effect absorption chiller using solution consisted of lithium bromide and water as a working fluid. the program provides the thermodynamic properties of all state points and the overall cycle performance. gomri, 2009 has conducted the comparative study between single-effect and double-effect absorption refrigeration systems. the results of their study showed there is minor difference between the exergetic efficiency of the system as well as the cop of double-effect system is about twice the cop of single-effect system. somers et al., 2011 designed a numerical study using aspen for singleand double-effect water/lithium bromide absorption chiller. predictions for the single and doubleeffect designs were within 3% and 5%, respectively for all absorption cycle parameters. wardono and nelson, 1996 carried out a system optimization for a double-effect lithium bromide absorption chiller driven by hot water based on the steady simulation of the chiller. further triple-stage cycle studies have also been conducted for instance gomri, 2008. he used exergy analysis to simulate a triple effect vapor absorption system at various operation conditions.. he calculated the exergy loss of each component of cycle and concluded that the maximum value of exergetic efficiency al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 228 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. for the triple effect refrigeration system was about 35.1 % and the temperature of low pressure generator was more important than the temperature of middle-pressure generator. he also showed that the maximum exergy and cop were found for a maximum value of low pressure generator and middle-pressure generator temperatures. as well as azhar and siddiqui, 2013 conducted a comparison study between triple effect absorption cycle and both of the single and double effect cycles. economic analysis and performance parameters were also investigated in their paper. they concluded that the triple effect cycle is more economical and more efficient than that of single and double effect cycles. in addition, the triple effect absorption cycle can required high temperature heat sources, therefore liquefied petroleum gas (lpg) and compressed natural gas (cng) were the best choice for operating the triple effect libr-h2o absorption systems. a little studies is mentioned in open literature about simulate of the triple-stage series flow absorption cycles because the cycle analysis is somewhat complex. therefore, this paper is concentrated on developing a computer program to simulate of the this cycle and simulation results is validated with actual absorption chiller cycle based on a 300 kw cooling capacity. the current study is capable to evaluate the performance of a triple-stage series flow absorption cycle working with libr-h2o pair under different operating conditions. 2. chiller description and working principle triple-stage absorption chiller usually constructs from an ordinary double-stage absorption chiller with an added high-pressure generator (hpg). a photograph of the triple-stage absorption chiller using libr–h2o solution are showed in figure 1. figure 1. three-stage steam-fired chiller system (source) it constructs from three generators (a high-pressure generator (hpg), a middle-pressure generator (mpg), and a low-pressure generator (lpg)), three condensers (a high-pressure condenser (lpc), a middlepressure condenser (mpc), and a low-pressure condenser(lpc) or main condenser), solution pump, three solution heat exchangers (hx1, hx2, and hx3), absorber, evaporator, and six throttling valves (tv1,tv2,tv3,tv4,tv5, and tv6). these components are connected in three closed loops and also connected with auxiliary systems as depicted in figure 2. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 229 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. these loops are as following: the first loop with low pressure consisted from generator (lpg), condenser(lpc), solution pump, solution heat exchanger(he1), absorber, evaporator, and solution and refrigerant throttling device(tv1 and tv6). the second loop with medium pressure consisted from generator (mpg), condenser (mpc), solution heat exchanger (hx2), solution and refrigerant throttling device (tv2, tv5). when the final loop with high pressure consisted from generator (hpg), condenser (mpg), solution heat exchanger (hx3), solution and refrigerant throttling device (tv3, tv4). on the other side, the auxiliary systems connect to chiller system which are as following: 1indirect-fired system connected with hpg to heat and maintain hot water supply temperature, 2cooling tower system to cool the refrigerant for both the lpc and absorber which is installed outer surface of the buildings, 3system consisted of storage tank and air-handling unit to conditioning space below ambient conditions which is typically installed outside the buildings. figure 2. state points of triple-stage libr-h2o absorption chiller system connected with auxiliary system al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 230 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. in this cycle, the solution exiting the absorber at state point 1 is first impelled to the hpg through three heat exchangers (i.e. he1, he2 and he3). at the hpg, the heat energy from an external heat source extracts the refrigerant vapor (water) from the solution. the refrigerant vapor in superheated state is then passed to the hpc at state point 22 and condenses into liquid releasing its heat. at this condenser, the condensation heat of refrigerant vapor is used to heat the mpg. the remaining solution, called strong solution leaving the hpg at state point 19, where flows through the heat exchanger (he3) and the reducing valve (tv3) towards the mpg at state point 21. in the mpg, some vapor is generated that enters the mpc at state point 15. the condensation heat in mpc is used to heat the lpg. the concentrated solution which is leaving the mpg at state point 12, then flows through heat exchanger (he2) towards the lpg at state point 14. more refrigerant is generated in lpg that enters the lpc at state point 7 from which heat is transferred to the cooling water flowing through the lpc. hence, the refrigerant which is entered in the lpc represents overall refrigerant coming from the three generators. the condensed refrigerant leaves the lpc and flows through the expansion valve (tv6) to reduce it pressure and enters to the evaporator at state point 9 and starts to boil after taking heat from the water circulated between the evaporator and the conditioning space. the vaporization heat of the refrigerant produces the cooling capacity of the whole system. the refrigerant vapor in the evaporator flows back into the absorber at state point 10 where it absorbs by the strongest solution coming from the lpg at state point 6. the cycle then gets completed. mathematical modeling some assumptions are made to simplify the model: 1the cycle model is based on steady state analysis, 2flow configuration is series, where the weak solution is pumped directly from absorber to hpg, 3the lithium bromide solution at the outlet of generators is weak solution and strong solution at the outlet of the absorber. 4the pressure inside each condenser equals to that in each the generator, 5the pressure inside the evaporator equal to the absorber , 6the flow through throttling valves are isenthalpic, 7the vapor produced in the mpg, hpg and evaporator is superheated, 8the solution of libr/water is saturated at outlet of both the lpg and the absorber 9the diluted solution pumped by the solution pump from the absorber to the hpg has constant mass flow rate. 10the exit temperature different between the mpc and lpg is equal to 5k 11the exit temperature different between the hpc and mpg is equal to 5k 12the refrigerant leaving the lpc is at the same temperature as the solution in the absorber exit. 13the heat transfer at the hpc equals to the heat transfer at the mpg. while the heat transfer at the mpc equals to the heat transfer at the lpg. the general equations of these principles are specified as: . . in out mass balance m m  (1) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 231 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved.     . . in out species balance mx mx  . . . . 0 in outin out energy balance q w m h m h       the circulation ratio (f) is defined as the ratio of weak solution flow rate to refrigerant flow rate. this parameter is very important for system design and is given by: . . w r m f m  (4) or it is expressed by terms of concentrations as , , , gen out gen out abs out x f x x   (5) the cooling mode coefficient of performance (copc ) for absorption chiller cycle is given by the following formula. c e hpg p chiller load cop energy input q q w    the refrigerant leaves the evaporator as saturated vapor at state point 10. the enthalpy is expressed by (ashrae fundamentals, 2009) 2 0.00124397 1.88060937 2500.559sat evap evaph t t      (7) on the other hand, the refrigerant vapor leaves both hpg and mpg at stat points 22 and 15 as superheated vapor, respectively. the enthalpy is expressed by (hosseini, 2011) sup 1.925 0,125 2365gen condh t t     (8) component analysis the cycle was treated as an independent element for each component with a certain number of input values. the components of triple stage absorption chiller with their state points can be depicted in figure 2. the components are: (1) condenser. (2) refrigerant expansion valve. (3) solution expansion valve, (4) (6) (2) (3) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 232 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. evaporator, (5) absorber, (6) solution pump, (7) solution heat exchanger, (8) generator. the mass, species and energy equations can be applied to each components of absorption cycle as shown in table 1. table 1: summary of equations for each component of the cycle components mass and spices balances energy balance state points absorber 1 10 6 1 1 6 6 ,m m m x m x m    10 10 6 6 1 1aq m h m h m h   1, 6, 10 solution pump 1 2 18 1 2x m m x m   1 1 2 2 1 2 1( )pump w m h m h w m h h     1, 2 lpc 8 17 7m m m  8 8 17 17 7 7 17 17 7 7 8 8 lpc lpc q m h m h m h q m h m h m h       7, 8, 17 mpc 16 24 15m m m  16 16 15 15 24 24 15 15 24 24 16 16 mpc mpc q m h m h m h q m h m h m h       15,16 , 24 hpc 23 22m m 23 23 22 22 22 22 23 23 hpc hpc q m h m h q m h m h     22 , 23 tv1,tv2, tv3 5 6 13 14 20 21, ,m m m m m m   5 6 13 14 20 21, ,h h h h h h   5,6,13,14,20,21 tv4,tv5, tv6 23 24 16 17 9 8, ,m m m m m m   23 24 16 17 9 8, ,h h h h h h   9,8,16,17,23, 24 he1 2 3 4 5,m m m m  1 1 3 2 4 4 5( ) ( )heq m h h m h h    2, 3, 4, 5 he2 3 11 12 13,m m m m  2 12 12 13 3 11 3( ) ( )heq m h h m h h    3, 11, 12, 13 he3 11 18 19 20,m m m m  3 11 18 11 19 20 19( ) ( )heq m h h m h h    11, 18, 19 , 20 lpg 14 4 7 14 14 4 4 m m m x m x m    14 14 7 7 4 4 7 7 4 4 14 14 lpg lpg q m h m h m h q m h m h m h       4, 7, 14 mpg 21 15 12 21 21 12 12 m m m x m x m    21 21 15 15 12 12 15 15 12 12 21 21 mpg mpg q m h m h m h q m h m h m h       12, 15, 21 hpg 18 22 19 18 18 19 19 m m m x m x m    18 18 22 22 19 19 22 22 19 19 18 18 hpg hpg q m h m h m h q m h m h m h       18, 19, 22 evaporator 9 10rm m m    9 9 10 10 10 9 e e r q m h m h q m h h     9, 10 other parameters heat exchanger effectiveness for he1, he2 and he3 he1 4 51 4 2 12 13 2 12 3 19 20 3 19 11 ( ) ( ) ( ) ( ) ( ) ( ) he he he t t t t t t t t t t t t             2, 4, 5 3,12, 13 11,19,20 he2 he3 circulation ratio for lpg, mpg, hpg lpg 14 4 7 4 14 lpg m x f m x x    4,7,14 mpg 21 12 15 12 21 mpg m x f m x x    12,15, 21 hpg 18 19 22 19 18 hpg m x f m x x    18,19, 22 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 233 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. model validation the available data in the literature were used to validate the simulation results. the theoretical results done by gomri, 2010 for the triple-stage absorption cycle are used. the comparative variation of the cop value with generator temperature is highlighted in figure 3. good agreements were observed between the present results and the presented by gomri, 2010. 120 140 160 180 200 220 240 260 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 tge n [°c] c o p tevap=4ctevap=4ctevap=4ctevap=4c tevap=6ctevap=6ctevap=6ctevap=6c tevap=8ctevap=8ctevap=8ctevap=8c tevap=10ctevap=10ctevap=10ctevap=10c figure 3. comparison of cop between the percent study (right legend) and gomri 2010 (left legend) at different generator exit temperature. simulation model in this study, a computational program is carried out using ees software (klein, 2009). this program is based on equations of mass and heat balances for the thermodynamic properties of lithium bromide–water. simulation of three-stage indirect-fired absorption chiller cycle includes inputs and outputs. the inputs of the system include the evaporator exit temperature, lpc exit temperature, hpg exit temperature, mass flow rate of refrigerant, effectiveness of heat exchangers. the outputs include the enthalpies, mass flow rates, libr concentrations, temperatures and pressures at each state points as well as cooling capacity, circulation ratio, heat transfer rates, coefficient of performance (cop). the three-stage indirect-fired absorption chiller manufactured by thermax company had a rated capacity of 300 kw and cop of 1.8 at design conditions. according to the eq. 6, the energy input to the chiller should not be excess 166 kw under rating conditions.the original chiller cycle can be worked effectively at 180°c hpg exit temperature, 30°c lpc exit temperature, 5°c evaporator exit temperature, 1 kg/s refrigerant mass flow rate, 0.65 heat exchanger effectiveness. under these operating conditions, the output parameters ( temperature, pressures, vapor quality, flow rate, concentration and concentration) and various state points (1-24) are delineated in table 2. the performance parameters results and heat transfer rates generated by ees for absorption chiller cycle are reported in table 3. results and discussion the variation in the results also are carried out for different ranges of operating conditions. exit temperature is varied in the following range: hpg temperature thpg= 150-230°c, mpg temperature al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 234 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. tmpg= 100-130°c and lpg temperature tlpg= 60-95°c, lpc temperature tlpc = 28-37°c, and evaporator temperature te = 5-14°c. mass flow rate of refrigerant is mr = 1.0 kg/s. heat exchangers effectiveness are 0.4, 0.5, 0.6 and 0.65 table 2:the computed state point results of the cycle. state points temperatur e(c) pressure (kpa) quality kg/kg mass flow rate(kg/s) enthalpy kj/kg concentration x(%) 1 30.0 1.60 1.000 57.0 46.57 2 30.0 4.25 1.000 57.0 46.57 3 47.7 4.25 1.000 97.1 46.57 4 69.5 4.25 0.8782 166.8 58.65 5 43.8 4.25 0.8782 116.3 58.65 6 50.5 1.60 0.0048 0.8782 116.3 58.65 7 47.5 4.25 0.0406 2588.4 8 30.0 4.25 0.1149 125.7 9 5 1.60 0.0271 0.1149 125.7 10 5 1.60 0.1149 2526.2 11 80.2 37.72 1.000 171.3 46.57 12 120.8 37.72 0.9188 268.0 58.65 13 73.2 37.72 0.9188 174.1 58.65 14 69.8 4.25 0.0025 0.9188 174.1 58.65 15 96.2 37.72 0.0406 2676.3 16 74.5 37.72 0.0812 311.8 17 30.0 4.25 0.0766 0.0812 311.8 18 133.1 238.04 1.000 293.7 46.57 19 180.0 238.04 0.9594 384.9 58.65 20 125.6 238.04 0.9594 277.4 58.65 21 74.4 37.72 0.0372 0.9594 277.4 58.65 22 152.4 238.04 0.0406 2770.6 23 125.8 238.04 0.0406 528.6 24 74.4 37.72 0.0934 0.0406 528.6 table 3: the performance parameter results of the cycle. parameter values heat absorber, qabs(kw) 293.745 heat evaporator, qevap(kw) 232.4 heat generator(lpg), qlpg (kw) 75.9 heat generator(mpg), qmpg (kw) 96.7 heat generator(hpg), qhpg (kw) 141.3 heat condenser(lpc), qlpc(kw) 80 heat condenser (mpc), qmpc(kw) 75.9 heat condenser(hpc), qhpc(kw) 96.9 solution heat exchanger(hx1), qhx1(kw) 35.1 solution heat exchanger(hx2), qhe2(kw) 40.4 solution heat exchanger(hx3), qhx3(kw) 27.9 solution pump, wp(kw) 0.1527 libr strong solution(%x6) 59 libr strong solution(%x16) 59.35 libr strong solution(%x26) 61.691 cop(-) 1.64 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 235 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figures 4 to 6 show the effect of the hpg, lpg and mpg temperatures, respectively on system cop and solution circulation ratio. these figures also show that the system cop values increase with increase in hpg, lpg and mpg temperatures. as seen in figure 4, the higher cop is found at hpg temperature of 210°c while the higher cop values are found for a maximum value of mpg and lpg temperatures as shown in figures 5 and 6 respectively. this temperature represents the optimum hpg temperature. this finding agrees with the results done by rabah gomri, 2008. furthermore, the increase in hpg, lpg and mpg temperatures produces increasing in refrigerant mass flow rate passing through the condensers thus leading to an decrease in the solution circulation ratio. 150 160 170 180 190 200 210 220 230 1.4 1.5 1.6 1.7 1.8 1.9 2 0 5 10 15 20 25 30 35 hpg te mpe rature (°c) c o p s o lu ti o n c ir c u la ti o n r a ti o copcop s.c.rs.c.r figure 4. variation of cop and solution circulation ratio at different hpg temperature. 100 105 110 115 120 125 130 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 0 5 10 15 20 25 30 35 40 45 50 m pg te mpe rature (°c) c o p s o lu ti o n c ir c u la ti o n r a ti o copcop s.c.rs.c.r figure 5. variation of cop and solution circulation ratio at different mpg temperature. figure 7. shows variation of libr concentration and cooling effect at different lpg temperature. when the lpg temperature increases, concentration of the strong solution in the generator increases, while concentration of the weak solution in the absorber remains constant therefore refrigerant circulation ratio al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 236 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. gradually decreases. the increase in strong solution in the generator should not be excess 70% to prevent the crystallization (solidified) phenomena. this means that the strong solution is limited by the lpg temperature. on the other side, the cooling effect increase with increasing the hpg temperature. in figure 8 shows the variation of the heat loads of generators, condensers and absorber with hpg temperature. as mentioned before, the increase in generators temperature causes the solution circulation ratio to decrease and consequently increases the heat loads of generators, condensers and absorber of the cycle. figure 9 displays that the system cop is declining with rising the lpc temperature. the refrigerant vapor requires to be cooled for improved condensation processes. in the same figure, the system cop attains his maximum value of 1.86 by decreasing the lpc temperature down to 38°c. on the other side, the circulation ratio increases with increasing the lpc temperature. figure 10 shows the effect of lpc temperature on cooling capacity of the cycle and libr concentration. the cooling capacity drops with increasing lpc temperature. this is because two reasons, the increase in both pressure of lpc and circulation ratio. in the same figure, the strong solution decreases and weak solution increases with increasing of lpc temperature. the effect of heat transfer rates for all components of chiller at different lpc temperature has been shown in figure 11. all the heat loads decrease when the lpc temperature increase. figure 12 the influence of the generators temperature on the circulation ratio per unit of cooling capacity. the circulation ratio and cooling capacity decrease with increasing of generators temperature. this implies to reduce this parameter( f/qe ). figure 13 shows the effect of the evaporator temperature on system cop at different values of hpg temperature. system cop values increase with the increase in evaporator temperature for constant hpg temperature. the effect of evaporator temperature on the system cop values becomes more with an increase in hpg temperature especially at lower values of evaporator temperature. figure 14 shows effect of evaporator temperature on cooling capacity of the cycle with different hpg temperature. as the evaporator temperature increases from 5 to 14 c, the cooling capacity of the cycle increases considerably at constant value of hpg temperature. since the low pressure of the cycle increases as the evaporator temperature increases. in figure 15 shows the variation of the system cop with evaporator temperatures for various the heat exchanger effectiveness. it observed that the system cop increases with the increase of both evaporator temperatures and heat exchanger effectiveness. as the heat exchanger effectiveness increase, the amount of energy adding to the hpg decreases and consequently this improve the system cop. figure 6. variation of cop and solution circulation ratio at different lpg temperature. 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 0 10 20 30 40 50 60 lpg te mpe rature (°c) c o p s o lu ti o n c ir c u la ti o n r a ti o copcop s.c.rs.c.r al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 237 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 7. variation of libr concentration and cooling effect at different lpg temperature. figure 8. heat transfer rates for all components of chiller system at different lpg temperature. 150 160 170 180 190 200 210 220 230 52 54 56 58 60 62 64 50 100 150 200 250 300 350 400 450 hpg te mpe rature (°c) l ib r c o n s e n tr a ti o n (% ) w eak solutionw eak solution strong solutionstrong solution q e v a p [k w ] qevapqevap 150 160 170 180 190 200 210 220 230 50 100 150 200 250 300 350 400 450 hpg te mpe rature [°c] h e a t t ra n s fe r( k w ) qevapqevap qlpcqlpc qmpcqmpc qhpcqhpc qlpgqlpg qmpgqmpg qhpgqhpg qabsqabs al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 238 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 9. variation of cop and solution circulation ratio at different lpc temperature. figure 10. variation of libr concentration and cooling effect at different lpc temperature. 28 29 30 31 32 33 34 35 36 37 1.4 1.5 1.6 1.7 1.8 1.9 5 8.5 12 15.5 19 22.5 lpc te mpe rature [°c] c o p s o lu ti o n c ir c u la ti o n r a ti ocopcop s.c.rs.c.r 28 29 30 31 32 33 34 35 36 37 50 51 52 53 54 55 56 57 58 59 60 61 62 100 150 200 250 300 350 400 lpc te mpe rature (°c) l ib r c o n s e n tr a ti o n (% ) q e v a p (k w ) qevapqevap w eak solutionw eak solution strong solutionstrong solution al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 239 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 11. heat transfer rates for all components of chiller system at different lpc temperature. figure 12. the effect the generators temperature on the circulation ratio per unit of refrigeration load 30 32 34 36 38 40 0 50 100 150 200 250 300 350 400 lpc te mpe rature (°c) h e a t t ra n s fe r( k w ) qabsqabs qlpcqlpc qmpcqmpc qhpgqhpg qlpgqlpg qmpgqmpg qhpgqhpg qevapqevap 50 60 70 80 90 100 120 140 160 180 200 220 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 ge ne rator te mpe rature (°c) f/ q e (1 /m w ) hpg temperaturehpg temperature mpg temperaturempg temperature lpg temperaturelpg temperature al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 240 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 13. variation of system cop and hpg temperature with different evaporator temperature. figure 14. variation of cooling effect and hpg temperature with different evaporator temperature. 5 6 7 8 9 10 11 12 13 14 0.5 0.75 1 1.25 1.5 1.75 2 2.25 te [°c] c o p hpgtemperature=150°chpgtemperature=150°c hpgtemperature=160°chpgtemperature=160°c hpgtemperature=170°chpgtemperature=170°c hpgtemperature=180°chpgtemperature=180°c hpctemperature=30°c 5 6 7 8 9 10 11 12 13 14 50 100 150 200 250 300 350 400 450 500 te [°c] q e [k w ] hpgtemperature=180°chpgtemperature=180°c hpgtemperature=170°chpgtemperature=170°c hpgtemperature=160°chpgtemperature=160°c hpgtemperature=150°chpgtemperature=150°c al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 241 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 15. variation of system cop and the heat exchanger effectiveness with different evaporator temperature conclusion a computer program written in ees software is modeled for the parametric analysis of triple-stage libr-h2o absorption chiller cycle. this cycle is analyzed under steady state operating conditions. the operating parameters are selected as follows: the hpg, mpg and lpg temperatures: thpg= 150-230°c, tmpg= 100-130°c and tlpg= 60-95°c, respectively, lpc temperature tlpc = 28-37°c, evaporator temperature te = 5-14°c; flow rate of refrigerant mr= 1 kg/s; four values of heat exchangers effectiveness   0.4, 0.5, 0.6 and 0.65. the study leads to the following conclusions: 1the generators temperature has a strong influence on the performance of the system as well as the condenser temperature. the system cop values increase with increase in hpg, lpg and mpg temperatures. on the other hand, the system cop is declining with rising the lpc temperature. 2when the lpg temperature increases, concentration of the strong solution in the generator increases, while concentration of the weak solution in the absorber remains constant therefore refrigerant circulation ratio gradually decreases. 3the increase in generators temperature causes the heat loads of generators, condensers and absorber of the cycle to increase, whereas the increase in lpc temperature implies to decrease the heat loads of the cycle. 4the cooling capacity of the cycle drops with increasing lpc temperature and rises with increasing lpg temperature. 5when lpc temperature increases, the strong solution decreases and weak solution increases 6system cop improves with the increase of both evaporator temperatures and heat exchanger effectiveness for constant hpg temperature. 5 6 7 8 9 10 11 12 13 14 1.5 1.55 1.6 1.65 1.7 1.75 1.8 1.85 1.9 1.95 2 2.05 2.1 2.15 2.2 2.25 te [°c] c o p =0.4=0.4 =6=6 =0.65=0.65 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 242 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. references 1. aphornratana satha and sriveerakul thanarath, 2007, experimental studies of a single-effect absorption refrigerator using aqueous lithium–bromide: effect of operating condition to system performance, experimental thermal and fluid science 32, 658–669. 2. ashrae fundamentals, thermodynamic properties of refrigerant, chapter 30, inch-pound edition, 2009. 3. azhar md and siddiqui m. a., 2013, thermodynamic analysis of a gas operated triple effect absorption cycle, international journal of innovative research in science, engineering and technology vol. 2, issue 5. 4. bahman ammar, 2011, modeling of solar-powered single-effect absorption cooling system and supermarket refrigeration/hvac system, university of south florida scholar commons msc theses. 5. chidambaram la , ramana as , kamaraj g, velraj r., 2011, review of solar cooling methods and thermal storage options. renewable and sustainable energy reviews;15:3220–8. 6. figueredo gustavo r., bourouis mahmoud, coronas alberto, 2008, thermodynamic modelling of a two-stage absorption chiller driven at two-temperature levels, applied thermal engineering 28 (2008) 211– 217. 7. florides, g.a., kalogirou, s.a., tassou, s.a., wrobel, l.c., 2003, design and construction of a libr– water absorption machine. journal of energy conversion and management vol.44 , pages 2483–2508. 8. gomri, r., 2009, second law comparison of single effect and double effect vapour absorption refrigeration systems, energy conversion and management, vol. 50, pp. 1279-1287. 9. gomri rabah, 2008, thermodynamic evaluation of triple effect absorption chiller, thermal issues in emerging technologies, theta 2, cairo, egypt, dec 17-20. 10. gomri rabah, 2010, investigation of the potential of application of single effect and multiple effect absorption cooling systems, energy conversion and management 51, 1629–1636. 11. grossman, g., zaltash, a., 2001, absim-modular simulation of advanced absorption systems, international journal of refrigeration. vol. 24 (6), pages 531–543. 12. ha q.p, 2013, a new single-effect hot-water absorption chiller air conditioner using solar energy, australasian universities power engineering conference. 13. hosseini l., design and analysis of a solar assisted absorption cooling system integrated with latent heat storage, master thesis, delft university of technology, holland, 2011. 14. joudi, khalid a., lafta, ali h., 2001. simulation of a simple absorption refrigeration system. energy convers. manage. 42, pages 1575–1605. 15. karimi, m. n., and s. k. kamboj. 2012. “exergy destruction and chemical irreversibilities during combustion in spark-ignition engine using oxygenated and hydrocarbon fuels.” international journal of mechanical & industrial engineering 2 (3): 7–11. 16. kim, d.s., infante ferreira, c.a., 2008, analytic modelling of steady state single-effect absorption cycles, international journal of refrigeration, 31 (6), 1012-1020. 17. klein, s.a., 2009. engineering equation solver, v8.411. f-chart software, madison, wisconsin. 18. marcos j.d., izquierdo m., palacios e., 2011, new method for cop optimization in waterand aircooled single and double effect libr/water absorption machines, international journal of refrigeration 34, 134 8-1359. 19. mehrabian, m.a., shahbeik, a.e., 2005, thermodynamic modelling of a single-effect libr–h2o absorption refrigeration cycle. proc. inst. mech. eng., part e: j. process mech. eng. vol. 219 (3), pages 261–273. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 243 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 20. misra r.d., sahoo p.k., gupta a., 2005, thermoeconomic evaluation and optimization of a doubleeffect h2o/libr vapor-absorption refrigeration system‖, international journal of refrigeration, vol.28, pp.331343. 21. saghiruddin, m., siddiqui, a., 2001. economic analysis of two stage dual fluid absorption cycle for optimizing generator temperatures. energy conv. manage. 42, 407. 22. sencan arzu, yakut kemal a., a. kalogirou soteris, exergy analysis of lithium bromide/water absorption systems, renewable energy 30, 645–657. 23.source:http://www.thermaxglobal.com/thermax-absorption-cooling-systems/vapour-absorptionmachines/steam-fired-chillers/ 24. somers c. , mortazavi a. , hwang y. , radermacher r. , rodgers p. , al-hashimi s.,2011, modeling water/lithium bromide absorption chillers in aspen plus, applied energy 88, 4197–4205. 25. ullah k.r., saidur r., ping h.w., akikur r.k. , shuvo n.h, 2013, a review of solar thermal refrigeration and cooling methods, renewableandsustainableenergyreviews24, 499–513 . 26. wardono, b., nelson, r., 1996, simulation of double-effect libr/h2o absorption cooling system[j]. ashrae j., vol. 38, no.10: p32-38. http://www.thermaxglobal.com/thermax-absorption-cooling-systems/vapour-absorption-machines/steam-fired-chillers/ http://www.thermaxglobal.com/thermax-absorption-cooling-systems/vapour-absorption-machines/steam-fired-chillers/ al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 95 effect of magnetized water on the properties of cement mortars at the earlier ages adnan flayih hassan qadisiya university / college of engineering civil engineering department abstract this study had been conducted to investigate the influence of magnetized water on the properties of cement mortars such as initial and final setting time, consistency and compressive strength with various water/cement ratios at the ages of 1 and 7 day. results of (50) specimens with different shapes had been adopted, which represented mortars specimens having compressive strength ranging from (5.5) to (32.5) mpa, initial setting time ranging from (4) to ( 32) minutes and final setting time ranging from (303) to (546) minutes, by using two types of mixing water , first one is tap water , and the other is magnetized water.the results showed that the use of magnetized water in producing cement mortars lead to increase in the compressive strength and decreasing in the initial and final setting time with compare to use of tap water. results also showed that the optimum water/cement ratio give best compressive strength under the conditions of this study was (0.45). key words: initial setting time, final setting time, consistency, compressive strength, tap water, magnetized water. منتية في األعمار المبكرةستأثير الماء الممغنط على خواص المونة ال دنان فليح حسنـــــع آلية الهندسة/ جامعة القادسية قسم الهندسة المدنية :الخالصة آزمن التجمد االبتدائي و , ةتيسمنلامونة ال عن تأثير استخدام الماء الممغنط على خواص أجريت هذه الدراسة للتحري . يوم7 و 1مقاومة االنضغاط تم فحصها بعمر , مختلفة ) سمنت / ماء( ائي و القوام و مقاومة االنضغاط باستخدام نسب النه ) 4 (بينزمن تجمد ابتدائي تراوح , mpa) 32.5 ( و) 5.5 ( بين ت نموذج ذات مقاومة انضغاط تـــــراوح50تم اعتماد نتائج األول هو ماء الحنفية و , دقيقة وباستخدام نوعين من ماء الخلط ) 546 (و) 303 ( اوح بينهائي تـردقيقة و زمن تجمد ن) 32 ( و يؤدي إلى زيادة مقاومة االنضغاط و يةمونة السمنتالالنتائج بينت إن استخدام الماء الممغنط في إنتاج . الثاني هو الماء الممغنط أعطت أعلى ) سمنت/ ماء( أما أفضل نسبة . قارنة مع استخدام ماء الحنفية نقصان في زمن التجمد االبتدائي و النهائي بالم ).0.45( ظروف هذه الدراسة آانت مقاومة انضغاط في ظل al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 96 introduction the water in the cement paste found in three types: free water which found in capillary pores, combined and adsorbed water, where the later types un-evaporation water and contribution in cement hydration. on the other hand the quality of used water plays a significant role: impurities in water may interfere with the setting of the cement, and adversely affect the strength of cement mortar or cause staining of its surface. for these reasons, the suitability of water for mixing should be considered. in many projects specification, the quality of water is covered by a clause saying that water should be fit for drinking. such water very rarely contains dissolved inorganic solid in excess of 2000 parts per million (ppm), and as a rule less than 1000 (ppm). the use of potable water as mixing water is generally satisfactory, there are some exceptions, for instance, in same arid areas, local drinking water is saline and may contain undesirable amounts of alkali carbonates and bicarbonates which could contribute to the alkali-silicate reaction(1). over the past years, research has been shown that magnetic treatment of water may reduce “hardness” caused primarily by calcium and magnesium. water treatment magnets can prevent deposits of these minerals on the inside of the pipe walls, and descale the existing buildup of solids(2). however, still limited amount of published literature is available about the effect of magnetized water on the properties of portland cement mortar or concrete. significant of research the main aim of this study is to remarking experimentally the behavior of cement mortars at earlier ages by using mechanism of water magnetizer depending upon bipolar system with different proportions of water/cement ratio ; therefore provide information on compressive, initial and final setting time of this type of cement mortars. also, to compare with the results of tap water. experimental program available materials in iraq were used in this research to produce cement mortars with mix proportions 1 (cement) : 3 (sand ) and by using two types of mixed water , the first one is tap water , and the other is magnetized water with discharge of (0.015 liter/second) . for the two types of water the (w/c) ratios used were 0.4, 0.45, 0.5, 0.55 and 0.6. the specimens tested for consistency, initial and final setting time. on the other hand, the compressive strength was measured for the cement mortar in 1 and 7 days. the specimens at age of (7) days cured in water then tested for compressive strength. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 97 materials used in this research 1.cement sulphate resistance portland cement type (v) manufactured by yamama cement factory was used in this study. the essential physical properties of this type of cement were tested in this study , as results of this research refer to that , while the chemical properties of this cement were conformed to standard specifications. 2. fine aggregate normal natural weight sand from the wilayt ali source was used as a fine aggregate, before its incorporation into cement mortar mix, the sand was sieved, and used with a saturated surface dry condition. the properties of the used sand in this study were conformed to the requirement of iraqi standard specification no.45-1984(3) zone (2) as shown in table (1). 3. mix water two types of water were used in this study, the first one is tap water and the second one is magnetized water .the magnetized water was produce by passing of tap water in the bipolar system from the positive north to the negative south perpendicular intersection the lines of magnetize, this mechanism obtained from the use of the magnetizer apparatus locally manufacture by al-juthari(4) as shown in the fig. (1). this apparatus have four circles, each circle contains two magnates with strength 500 gauss and discharge 2000 liter / hour. test procedures 1.consistency , initial and final setting time the initial and final setting time test were carried out according to astm designation: c 191(5) by using vicat needle apparatus, figs. (2) and (3), which consists of a movable rod weighing 500 grams; one end, the plunger end, being 10 mm in diameter for a distance of at least 5 cm and the other end having a movable steel needle, 1 mm in diameter and 5 cm in length. the rod is reversible and can be raised or lowered by the set screw, which has an adjustable indicator. the latter moves over a graduated scale attached to the frame. the cement paste is held in a circular mould, which has an inside diameter of 5 cm and has a height of 5 cm. the average results of three specimens were adopted at each test. 2. compressive strength the compressive strength test was determined according to bs.1881-part 116 -1989(6). a cube specimens with dimensions 100 mm were tested by using standard testing machine with a capacity of 2000 kn, fig.(4).the test was conducted at ages of (1) and (7) day and the average results of three specimens were adopted at each test. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 98 results and discussion the results of the experimental work for this research are listed in table (2), and then represented in figures (5) to (16). figures (5) and (6) represent the effect of magnetized water on the initial and final setting time respectively. from these figures with addition to figures (13) and (14) can be seen that the increasing of initial and final setting time for both types of mix water with the increasing of water/cement ratio. the percentages of increasing in the initial setting time at w/c = 0.6 with respect to w/c = 0.4 were 220% and 525% for tap and magnetized water respectively, while the corresponding percentages of increasing in finial setting time at w/c = 0.6 with respect to w/c = 0.4 were 45.6 % and 44.8 % for tap and magnetized water respectively. this may be attributed to excessive water quantity and its inverse effect on the setting, where lead to elongation the setting time of cement paste. figures (5), (6), (9) and (10) showed that the use of magnetized water lead to reduce the initial setting time with percentage of 60% for w/c = 0.4 and 21.8% for w/c = 0.6 compared with the use of tap water. in the other hand the corresponding percentages of decreasing in finial setting time were 19.2% for w/c = 0.4 and 19.6 % for w/c = 0.6 compared with the use of tap water. this may be attributed to the use of magnet mechanism, which lead to redistribution of the water molecules and change interior angle between them, finally decreasing the surface tension(7), increasing the solubility of water and cause the setting in short time. figures (7) and (8) represent the effect of magnetized water on the compressive strength of cement mortar at ages of (1) and (7) day respectively. from these figures can be seen that the use of w/c = 0.45 give higher value of compressive strength in both ages. this is related to the volume of hydration products and the magnitude of calcium silicate hydrate (c-s-h) gel in the total hydration volume; where the c-s-h gel play essential role in the progressive of strength for the cement paste, where the ( w/c = 0.4 ) having lower c-s-h gel due to finding unhydration cement particles in the volume of hydration products, also (w/c > 0.45) give lower c-s-h gel due to finding percent of capillary pores filling with water. figures (7), (8), (11) and (12) demonstrated that the use of magnetized water lead to increase the compressive strength at the earlier ages. the percentages of increasing in the compressive strength at age of (1) day due to use magnetized water compared with the specimens made with tap water with w/c = 0.4 and 0.6 were 9 % and 8.3% respectively, while the corresponding percentages values for the compressive strength at age of (7) day were 22.7% and 20%. this performance may be due to shortly setting time of cement paste, increasing its solubility and ability to form gel of calcium silicate hydrate, (i.e. increasing the speed of hydration to form cs-h gel). al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 99 figures (15) and (16) represented percentage of increasing in compressive strength at ages of (1) and (7) days for two type of mixed water compared with w/c = 0.4. these figures showed that the percentage of increasing in compressive strength decreased with the increasing of w/c ratio. this behavior may be due to inverse effect of excessive water quantity on the strength, where lead to produce more porosity cement paste and increase the capillary pores filling with water the consistency test results didn't give apparent performance, where all experimental results (unless cement mortar made by magnetized water with w/c = 0.4) have full penetration of steel needle to the surface of cement mortar, however can be conclude that the magnetized water lead to decrease the consistency, where the result of steel needle penetration at (w/c = 0.4) was equal to zero. this behavior may be related to the decreasing the setting time by using magnetized water. the best fits lines and curves for the results of this study were draw with figures (5) to (8), and can be express by the following equations according to the graphed program: 1. initial setting time a. the equation of best fit line for cement mortar made with tap water: y= 114 x – 36.8 (1) with coefficient of determination (r-squared) = 0.976 b. the equation of best fit line for cement mortar made with magnetized water: y=102 x – 38 (2) with coefficient of determination (r-squared) = 0.9633 2. final setting time a. the equation of best fit line for cement mortar made with tap water: y= 882 x – 6.8 (3) with coefficient of determination (r-squared) = 0.969 b. the equation of best fit line for cement mortar made with magnetized water: y= 676 x – 27.6 (4) with coefficient of determination (r-squared) = 0.989 3. compressive strength at age of (1) day a. the equation of best fit curve from 4th degree for cement mortar made with tap water: y= -23333 x4+ 47666 x3 – 36341 x2 + 12250 x – 1533 (5) with coefficient of determination (r-squared) for 4th degree = 1 b. the equation of best fit curve from 4th degree for cement mortar made with magnetized water: al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 100 y= -16666 x4+ 35000 x3 – 27458 x2 + 9527 x – 1225 (6) with coefficient of determination (r-squared) for 4th degree = 1 4. compressive strength at age of (7) days a. the equation of best fit curve from 4th degree for cement mortar made with tap water: y = -76666 x4+ 157000 x3 – 120008 x2 + 40557 x – 5085 (7) with coefficient of determination (r-squared) for 4th degree = 1 b. the equation of best fit curve from 4th degree for cement mortar made with magnetized water: y = -66666 x4+ 137333 x3 – 105633 x2 + 35926 x – 4525 (8) with coefficient of determination (r-squared) for 4th degree = 1 conclusions the following points are fixed depending on the analysis of the results obtained from this study. 1. there is apparently different between the results adopted from used of magnetized water and tap water in producing cement mortar. 2. the initial and final setting times decreasing by using magnetized water. 3. the compressive strength of cement mortars at earlier ages significantly increase by using magnetized water. 4. the optimum water /cement ratio gave best compressive strength under the conditions of this study was 0.45. 5. the consistency of cement mortar decreasing by using magnetized water as a mixed water. references 1. a.m.neville ,"properties of concrete",3rd edition, 183 p,. 2. master magnetics inc., "water treatment magnets ",watermags. pdf, internet file, pp1-4. . بالسمنت البورتالنديةالخاص, 1984 -5المواصفة القياسية العراقية رقم .3 4. al-juthari , hiawe wawa "technical paper " , qadissiya university, pp 1-3, 2006. 5. astm designation: c 191 "standard test method for setting time of hydraulic portland cement by using vicat needle ", pdf, internet file, 50 p. 6. bs.1881. part 116" method for determination of compressive strength of concrete cubes ", british stander institution, 1992, 3 p. 7. al-juthari, hiawe wawa "effect of irrigation water quality, magnetic water and potassium fertilizer levels on some chemical properties of soil, growth and yield of corn", m.sc. thesis, university of baghdad – college of agriculture2006, 19 p. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 101 table (1): properties of sand used throughout this study table (2): the results of experimental work 1.grading test result iraqi standard specification no.45-1984 size of sieve % passing zone 1 zone 2 zone 3 zone 4 10 mm 100 100 100 100 100 4.75 mm 98.6 90-100 90-100 90-100 95-100 2.36 mm 92.0 60-95 75-100 85-100 95-100 1.18 mm 89.0 30-70 55-90 75-100 90-100 600 µ m 51.1 15-34 35-59 60-79 80-100 300 µ m 25.0 5-20 8-30 12-40 15-50 150 µ m 8.80 0-10 0-10 0-10 0-15 2.deleterious substations test result iraqi standard specification no.45-1984 ( allowable limit)% material % deleterious substations natural sand sand of crushed gravel lightness materials 0.07 1 1 percentage of clay 0.00 1 1 materials passing from size 75µ m 2.40 5 15 salts as so3 0.41 0.5 for the foundation concrete and the parts exposed for water and 0.75 for other 0.5 for the foundation concrete and the parts exposed for water and 0.75 for other consistency initial setting time final setting time compressive strength tap water (mpa) magnetizer water (mpa) w/c tap water (mm) magnetizer water (mm) tap water (min.) magnetizer water (min.) tap water (min.) magnetizer water (min.) 1 day 7 days 1 day 7 days 0.40 50 0 10 4 375 303 5.5 22 6 27 0.45 50 50 14 7 390 327 7 27 8 32 0.50 50 50 18 13 439 366 6.5 25 7.5 30 0.55 50 50 27 16 489 393 6.5 24.5 7 29 0.60 50 50 32 25 546 439 6 22.5 6.5 27 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 102 figure (1): magnetizer apparatus figure (2): vicat needle apparatus figure (3): vicat needle apparatus with specimen figure (4): compression machine al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 103 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 5 10 15 20 25 30 35 in iti al s et tin g t im e (m in ut es ) cement mortar with tap water cement mortar with magnetized water figure (5): effect of magnetized water on the initial setting time of cement mortar. 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 275 325 375 425 475 525 575 f in al s et ti ng t im e (m in ut es ) cement mortar with tap water cement mortar with magnetized water figure (6): effect of magnetized water on the final setting time of cement mortar. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 104 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 f in al s et tin g t im e (m in ut es ) cement mortar with tap water cement mortar with magnetized water figure (7): effect of magnetized water on the compressive strength of cement mortar at age of (1) day. 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 20 22 24 26 28 30 32 34 36 f in al s et ti ng t im e (m in ut es ) cement mortar with tap water cement mortar with magnetized water figure (8): effect of magnetizer water on the compressive strength of cement mortar at age of (7) days. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 105 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 10 20 30 40 50 60 70 p er ce nt ag e of d ec re as in g in in iti al s et tin g ti m e % figure (9):percentage of decreasing in initial setting time due to use magnetized water compared with cement mortar made by tap water 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 2 4 6 8 10 12 14 16 18 20 22 24 p er ce nt ag e of d ec re as in g in fi na l s et tin g ti m e % figure (10): percentage of decreasing in final setting time due to use magnetized water compared with cement mortar made by tap water al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 106 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 2 4 6 8 10 12 14 16 18 p er ce nt ag e of in cr ea si ng in c om pr es si ve s tr en gt h % figure (11): percentage of increasing in compressive strength at (1) day due to use magnetized water compared with cement mortar made by tap water 0.35 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 2 4 6 8 10 12 14 16 18 20 22 24 26 p er ce nt ag e of in cr ea si ng in c om pr es si ve s tr en gt h % figure (12): percentage of increasing in compressive strength at (7) days due to use magnetized water compared with cement mortar made by tap water al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 107 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 100 200 300 400 500 600 pe rc en ta ge o f i nc re as in g in in iti al s et tin g tim e co m pa re d w ith w /c =0 .4 cement mortar with tap water cement mortar with magnetized water figure (13): percentage of increasing in initial setting time for two type of mixed water compared with w/c = 0.4 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 10 20 30 40 50 p er ce nt ag e of in cr ea si ng in fi na l s et tin g tim e co m pa re d w ith w /c =0 .4 cement mortar with tap water cement mortar with magnetized water figure (14): percentage of increasing in final setting time for two type of mixed water compared with w/c = 0.4 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 108 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 5 10 15 20 25 30 35 pe rc en ta ge o f i nc re as in g in c om pr es si ve s tr en gt h co m pa re d w ith w /c =0 .4 cement mortar with tap water cement mortar with magnetized water figure (15): percentage of increasing in compressive strength at (1) day for two type of mixed water compared with w/c = 0.4 0.40 0.45 0.50 0.55 0.60 0.65 (w/c) ratio 0 5 10 15 20 25 30 35 p er ce nt ag e of in cr ea si ng in c om pr es si ve s tr en gt h co m pa re d w it h w /c =0 .4 cement mortar with tap water cement mortar with magnetized water figure (16) percentage of increasing in compressive strength at (7) days for two type of mixed water compared with w/c = 0.4 <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 103 experimental and analysis of the effectiveness of film cooling in gas turbine blade technique hyder h. balla al-furat al-awsat technical university, engineering technical collage najaf, iraq received on 18 december 2016 accepted on 22 january 2017 abstract this study employed the use of experimental data of film cooling effectiveness using corrugation film cooling hole. effects of blowing ratio in conjunction with twisted angles (0°, 90°, 180°, 270° and 360°) were also investigated. recently, the utilization a vortices in enhancing thermal transfers is becoming increasingly attractive as a result of its dual advantages including its surfaces that are extended, turbulent twisted holes as well as coarseness. results of enhancement in the effectiveness ranging from 1.2–2.2 times those from conventional smooth film cooling holes with significantly increased coefficient of thermal transfer ranging from 1.50 to 2.70 times those of the conventional film cooling holes with smooth surfaces. both the numerical and the experimental analysis of the effectiveness of film cooling were authenticated by results from pervious related studies. the authors found and concluded thus, effectiveness of twisted film cooling holes at rectangular spiral corrugation shape was higher in comparison to holes with cylindrical shape. the effectiveness of film cooling for the twisted holes were observed to be hugely influenced by inclination angle between the main and the secondary holes of the film cooling hole antivortex. key words: film cooling, anti-kidney vortex, geometry of jet, experimental work, cooling performance, losses التحدید التجریبي لفعالیة تقنیة التبرید الغشائي لریشة التوربین الغازي مدرس دكتور/ حیدر حسن عبد بالة نجف/ جامعة الفرات االوسط التقنیة -الكلیة التقنیة الھندسیة رالكلمات المفتاحیة: تبرید غشائي، مضادات الدوامات ، ھندسة النفاثات ، عمل تجریبي، كفاءة التبرید، خسائ 1. introduction recently, the frequency of utilizing film cooling in the reduction of the heat burden on highpressure turbine airfoil in attempt to achieve higher turbine inlet temperature for the purpose of enhancing thermal efficiency is on the increase. the heat transfer enhancement basically based on the adopting of many tools that induces a swirl and vortices at the secondary flow region, which mixed the fluid layers with the core flow and increasing the surface area [1]. a film of cooling air is then produced over the blade surface, thereby reducing the overall heat burden to on the blade surface. the effect of swirling movement on film cooling has equally been demonstrated to be important in both turbine blades and turbine vanes [2]. this is owing to the fact that in recent aircooled turbine blade and turbine vanes , impingement cooling and a serpentine flow passage with a turbulent promoter are employed in cooling the airfoil and end wall internally. the thrust for an improvement in cooling performance has made film cooling designs the focus of several studies. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 104 with regard to this, one of the main aspect of approach in achieving enhanced cooling performance has been shown to be the alteration of the morphology of film cooling hole to modulate jet lift off and subsequently reduce the overall burden of hot gas entrainment which is typically associated with the conventional round jets. even though single film cooling hole designs usually involve range of geometrical variables such as the shape of the hole, jet inclination angle (β) and twisted film cooling hole angle (α), only variations of the hole configuration was considered in the present work. detailed reports on other geometric measurement has been previously documented in related studies by other authors [3]. james d. [4] investigated “anti-vortex” film cooling concept and proposed the addition of two additional holes from the primary holes for the purpose of generating vortices to counter the detrimental kidney vortices from the major jet as depicted in fig. 1. the concept of anti-vortex film cooling hole had been computationally modelled for single rows of 30° angled holes on a flat surface. a little modification in the concept of the anti-vortex whereby the branched holes exit adjacent to the major hole has been computationally investigated for blowing ratios of 1.0 and 2.0 at density ratios between 1.0 and 2.0. the outcome of the computational investigation show that the modified design improves the effectiveness of the film cooling relative to the round hole baseline and previous anti-vortex cases, which confirms the findings of the experimental studies. fig. 1 front view of the adjacent anti-vortex design [4]. a commonly known and exhaustively investigated property of the flow from round film cooling holes is has been shown to be the counter rotating vortex pair which is responsible for the separation of the cooling jet from the surface at a significantly high blowing ratio. this phenomenon is depicted in fig. 2. the counter-rotating vortex pair entrains the hot free stream gas and lifts the coolant away from the surface، thereby significantly reducing its efficiency. the counter-rotating vortex pair is has been previously described by haven et al. [5] fig. 2 counter-rotating vortex pair and jet lift-off, [5] al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 105 several investigations on film cooling effects have been conducted. early works in this area had been summarized in a previous review [6] while the latest in this field were reviewed by bogard and thole [7]. other researchers [8, 9] have similarly investigated the flows blowing via inclined discrete holes. several other experimental endeavors to enhance film cooling effectiveness through adoption of film cooling holes whose exits are expanded had been conducted by several other authors [10-13]. an excellent and summarized profile of film cooling effects has been recently documented [14]. several other new ideas for regulating an anti-kidney vortex structure had been similarly documented. two other different film cooling designs with different compound angles had been previously evaluated in a related study [15]. recently, additional cooling air jet has been proposed in a circular film cooling hole to modulate and subsequently crash the kidney-type vortex [16]. a generator of the delta vortex origin was placed at the downstream of the ejection hole. amazingly, the vortex generator introduced was observed to be very effective in producing generating an anti-kidney vortex pair [1]. abdulwahid et.al. [17] had experimentally investigated heat transfer dynamics within corrugation film cooling holes of varying cross sectional area square, rectangular and circular. circumstances of this investigation of blowing ratios ranging from 0.5-2.0 and hole angle at 30°. the results of experimental studies employing swirling film cooling flow has shown that rectangular film cooling holes induce decrease in the effectiveness of the film cooling at a low swirl but enhanced it at a high swirl number. the resulted anti-kidney vortex pair generated in the said study triggered coolant to be blown toward the wall while concurrently spreading it out along it. a ‘sister hole’ design which led to an increase in film cooling effectiveness owing to previously established vortex structure which was investigated in an earlier study [18]. such cooling methods employ the motion of vortex of the cooling air to enhance the coefficient of heat transfer. additionally, the film cooling air was normally ejected from the air sources, which still maintained either weak or strong vortex. the motion of the vortex in the bleeding film cooling air may enhance the effectiveness of film cooling, especially where the strength of the vortices could blend with the film cooling conditions [19]. in addition to the use of motions of the vortex in the inner cooling airflow. the development of a new cooling method that could make use of actively produced vortex motion in the cooling flow of the film will be very crucial in enhancing the effectiveness of film cooling in an elevated temperature gas turbine for both its vanes and blades. a measurement system that would enable the achieving of the rapid and averaged time mixing of flow fields of the film cooling air and mainstream utilizing laser-induced fluorescence (lif) technique which was recently developed [20]. it was further demonstrated that the technique could be a powerful tool for studying the mechanisms of the mixing process in film cooling in view of rapid fields. abdulwahid et. al. [21] investigated a new numerical method of film cooling employing swirling coolant flow via a rectangular twisted film cooling holes with spiral corrugated tube. the constraints of this study were the blowing ratios which ranged from 0.25-4.0 and the angle of hole which was at 30°. the results of the effectiveness of the cooling obtained were compared against a standard untwisted tube. the results of the study revealed that the overall thermal effectiveness was enhanced significantly when the difference in temperature between the air flows was at 25 degrees. such enhancement was is supported by heat transfer improvement that was obtained from 19.7% to 57.4%. the influence of swirled film cooling air on the effectiveness of film cooling, employing a twisted tape in a circular cooling hole has been previously investigated and an enhancement in the effectiveness of film cooling in conjunction with the swirling coolant flow was observed [22]. however, the study neither provided quantitative description nor do they present experimental findings that shed more light on the mechanism of film cooling with the swirling flow. although effects film cooling have been extensively studied, studies treating effectiveness of film cooling with a swirling flow are very few. recently, film cooling arrangement aimed at cooling the end wall of first vane of a hightemperature industrial gas turbine built with a hexagonal shell structure with two other inclined impingement nozzles on the cover plate of the hexagonal shell has been proposed. the swirling al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 106 coolant flow produced by these inclined impingement nozzles was anticipated to blow through a film-cooling hole on the end wall. this concept could control not only the film-cooling airflow rate but also blowing ratio which could eventually give rise to optimize the effectiveness of film cooling on the end wall. hence, the current study presents an experimental as well as numerical studies of a new film cooling corrugation shapes (rectangular, circular and hexagonal) in film cooling corrugated holes in order to investigate evaluate the effects of the corrugation shape on effectiveness enhancement and heat transfer coefficient as well as to correlate an empirical expression for effectiveness and heat transfer coefficient. 2. experimental apparatus and procedure table 1 details of the experimental conditions actual test model red br red br t∞ (°k) one hole 6 2 0 0 0.5 6195 0.52 350 one hole 1.0 6185 1.0 352 one hole 2.0 6194 2.01 349 two holes 0.5 6201 0.51 350 two holes 1.0 6201 1.0 353 two holes 2.0 6204 2.0 352 three holes 0.5 6210 0.5 355 three holes 1.0 6211 1.01 348 three holes 2.0 6217 1.98 350.9 the studied configuration: three study models are used in this experiment and these were namely test models with one hole, two holes and three holes respectively. the 3 different test models were all used in the thermal studies. figure 3 revealed the well-known non-dimensional configuration of the hole for thermal investigations. the cooling hole employed was a conventional rectangular twisted hole with inclination to the main direction of flow at angle, β = 30˚, 45 and 90 as depicted in fig. 7. the cooling hole was separated in lateral direction at 6d. the diameters of the hole for the thermal and aerodynamics investigation were adjusted to 7 mm while the width and the breath of the plate tested was fashioned to offer the hole length to diameter ratio, l/d = 6. the models tested were produced from acrylic plate and the production precision of ±0.1 mm. the setup of the experiment for the thermal evaluation employed in the current investigation is depicted in fig. 4. the facility comprises of a wind tunnel utilised for delivering the mainstream air through separate blowers for the secondary air. the test canal cross section was designed to have 150 mm width as well as 150 mm height with a sharp upstream edge to restructure the boundary layer within the test section. the test or study models originated from acrylic plates possessing thermal (heat) conductivity of 0.19 w.m-1k-1 with 7 mm diameter of cooling hole. thermocouple was placed on the test model to generate data on temperature which are essential for calibration, and were utilised to approximate the emissivity of the test surface. during the determination, the secondary air was regulated at a temperature of 50°k less than the major stream temperature. the ir camera used was fluke i400 which has a maximum recording capacity of 30 frames per second with the determination lasting for a period of three minutes. the camera was operated in a long-wavelength infrared band with spectrum ranging from 8 to 13 μm. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 107 fig. 3. the setup of the thermal experiment. fig. 4. experimental set-up scheme. case 1 (α =360°) case 2 (α =270°) case 3 (α =180°) case 4 (α =90°) case 5 (α =0°) fig.5. rectangular geometry varied corrugations. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 108 (a) (b) (c) fig. 6. three shapes of corrugation; (a) rectangular (b) hexagonal (c) circular. case 3 (β =90°) fig.7. variation of holed angle at 30°, 45° and 90° for rectangular geometry. table 2: film cooling hole of experimental and numerical tests no. of hole br β rem rej status 1 0.254.0 30°,45° and 60° 27.56*10 3 6200 numerical and experimental 1 0.254.0 30°,45° and 60° 30.66*10 3 6200 numerical and experimental 1 0.254.0 30°,45° and 60° 44.15*10 4 6200 numerical and experimental 1 1.0 30° 27.56*10 3 6200 smooth hole case 1 (β =45°) case 1 (β =30°) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 109 numerical and experimental incropera et. al. [23] 1 1.0 35° 35.86*10 4 smooth hole num. leedom et. al. [25] 2 0.254.0 30°,45° and 60° 27.56*10 3 6200 numerical and experimental 2 0.254.0 30°,45° and 60° 30.66*10 3 6200 numerical and experimental 2 0.254.0 30°,45° and 60° 44.15*10 4 6200 numerical and experimental 3 0.254.0 30°,45° and 60° 27.56*10 3 6200 numerical and experimental 3 0.254.0 30°,45° and 60° 30.66*10 3 6200 numerical and experimental 3 0.254.0 30°,45° and 60° 44.15*10 4 6200 numerical and experimental 3. numerical procedure 3.1. geometrical configuration stainless steel film cooling holes of spiral corrugation having 7 mm hydraulic diameter were modelled with the same corrugation features and corrugation profile as those of the spiral corrugation film cooling holes used in the experimental tests to curtail the deviation between experimental and numerical data. in addition, one smooth and one corrugated tubes were also modelled to be numerically simulated as shown in table 2. further enhancement were achieved by using corrugation in the turbulent flow region accompanied with pressure drop. individually corrugated tubes were modelled according to the methods described by incropera [23] for the purpose of validation. fig.8 boundary condition configuration. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 110 3.2. governing equations the governing mathematical expression of the flow problem in the cartesian coordinates system were derived from the following equations conservation of mass : .!"#$ = 0 (1) momentum equation: .%!"#$&"#$' = ( ) + .%* ,"#$' (2) energy equation: .%!&"#$&-/&1' = .23& 14 (3) results and discussion of heat transfer 3.3. the transient heat transfer theory: the transient heat flow over a flat plate maintained at an initial even temperature ti, at time t > 0 is depicted in fig. 9. the condition of the convective boundary was applied on the plate with the assumption that the conduction of heat is was mainly in x-direction. the energy balance on the plate was calculated using the following expression: fig. 9 flow over a flat plate. the 1-d transient conduction equation is expressed as: &&&&&&&&&&5 67 586 = 9 : 57 5; (5) the boundary conditions (bc) was obtained from the following expression; at x=0, (k 5758<8>? = h@ta ( t2?b;4c the initial condition (ic) was derived from the expression below at t=0, t=ti from equation (5), one more bc is required in order to derive a solution since eq. (5) is a partial differential equation of the 2nd order, where ti= initial temperature of the test surface tw= the prescribed wall temperature tm= mainstream temperature α= thermal diffusivity of test surface k = thermal conductivity of test surface t = time when the ir image was taken after the test was initiated. h = heat transfer coefficient the convective boundary surface and the non-dimensional temperature of incropera et. al. [21] was employed as shown in the expression below: al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 111 !" # $" # = 1 % &exp'( )*+ ,) -.erfc& (/*+ , . (6) locally mixed two streams were employed to evaluate the film temperature. for the purpose of this investigation, heat flux into the surface was calculated using the expression shown below: fig. 10 flow over a flat plate in adiabatic surface, the temperature of the adiabatic wall the same with the film temperature, where the film temperature (tf) and the heat transfer coefficient (hf) were unknown variables. thus, the film cooling effectiveness (0), which is a non-dimensional temperature was employed to determine the unknown tf given that tm and tc are known as depicted in eq. (6): 0 = t2 % t3 t4 % t3 or t2 = 05t4 % t36 7 t3 = 0t4 7 51 % 06t3 (7) such that values of the film cooling effectiveness falls within the range of 0 and 1 with regards to its lowest and highest values respectively. by substituting tm in equation (7) with tf in equation (6), the equations for the two unknown variables, h and η were obtained as depicted in the following expression: 89 % 8: = 1 % &;<>' ?)@a b) -.;cde & ?/@a b . × [f8g 7 51 % f68h % 8:]iiiiiii(8) the results generated from the three test models were compared with experimental studies on standard smooth holes that were previously described [23]. the validation analysis is presented in fig. 11 and comparison with previous studies [37, 39] are depicted in fig. 12. comparison between both the experimental as well as numerical data sst kω turbulence model are equally presented in fig. 12. the results have demonstrated that the deviation was less than 2%, which falls within the acceptable range, and the numerical setup and the simulations were similarly acceptable. the twisted angle was found to induce increase in the effectiveness, these forms causes: • an increase in the angle of the vortices in jet flow. • a decrease on the thermal stress exerted on the walls as a result of the difference in expansion with respect to the grill. • enables secondary movements of the fluid as a result of the alternating changes in the curves in order to maintain high pressure loss • increases the surface plates convection as. from fig. 13-15, it could be deduce that the optimum effectiveness was achieved at both the rectangular cross section as well as at twisted angle (360°) owing to the optimum vortices in the jet flow. these twisted film cooling holes produced a swirling within the blade of the turbine, with α angle to impingement with main stream. it was found that increase in twisted angle (0°, 90°, 180°, 270° and 360°) induces corresponding increase in the effectiveness, while a decrease was recorded when the blowing ratio (br) was increased owing to the fact that the jet flow becomes faster on surface of the blade turbine. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 112 it was similarly found that the effectiveness of the rectangular hole shape increase when compared with the circular hole shape which ranges from 40 to 70.17% and from 40 to 65.523 % in the case of hexagonal cross section area. the results were compared with the experimental data of straight fan shaped hole (standard smooth hole) by sinha [37], and pedersen, [39]. the conditions of previous experimental investigations have a br of 1.5 and angle of secondary flow 35° as shown in fig. 11. this figure has two regions, with each having specific symptoms. the first region of x/dh range 1-5 exhibits a rapid decrease of cooling effectiveness and high cooling effectiveness value in the current experimental results comparison to the other pervious study [37, 39]. the second region exhibit a lesser decrease, but the cooling effectiveness value of current and literature reports were so closed. this behavior resulted owing to the different secondary coolant hole angle employed. the deviation between the current study and the other two studies were ±2.5% and ±3.5% respectively. this deviation is within the acceptable range, as it was mentioned in a previous related study ghorab, 2009 [38] stated a maximum deviation ±10%. fig. 11 comparison between the conventional standard smooth hole [37] and [39] present experimental findings. the reliability of the results is very important, because the validation helps to give an imagination for the obtained data whether the research going to wrong or right way. the lateralaveraged film cooling effectiveness was compared with a cylindrical smooth hole under similar test conditions, as depicted in fig. 14. the br was 1.5 while the inclination angle relative to the wall surface is was at 30°. compared with studies conducted previously [40, 41], from x/dh range of 1.0 – 10, except for a slight difference in values, the general tendency was consistent with the published findings of central averaged film cooling effectiveness as presented in fig. 14. the deviation between the current study the two other two studies were ±2% and ±3% respectively. fig. 12 comparison between the conventional smooth hole [40, 41] and the present experimental findings 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 1 2 3 4 5 6 7 8 9 10 11 c o o li n g e ff e c ti v e n e ss x/dh present exp. study, br=1.5, β=30° pedersen [39], br=1.5, β=35° sinha [37], br=1.5, β=35° 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 1 2 3 4 5 6 7 8 9 10 11 c o o li n g e ff e c ti v e n e ss x/dh present exp. study br=1.5, β=30° huichuan [41], br=1.5, β=30° dhungel et al. [40], br=1.5, β=30° al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 113 fig. 13a shows that the secondary hole angle β = 30° has the optimal cooling effectiveness amongst all the arrangements at br of 2.0, with β = 45° and β = 90° offering the least protection. the increased effectiveness values provided by the secondary cooling hole angle β = 30° continued at distances downstream greater than x/dh 11.0. it is imperative to note that the coverage values of all the holes are different when looking at this data. on the other hand, the coverage for β = 90° was 22% and 40% for β = 30°. this implies that the highest value of β = 30° which was at the exit of the holes should be towards η = 0.4, while it should only be 0.22 for β = 90°. the implications of this is discussed later in this section. hence, only the general trends were discussed, in the context of br parameters as outlined in the literature at br of 1.5, as presented in fig.15b, hole angles β = 30°, β = 45° and β = 90° started lifting off. this is seen in the cooling effectiveness of the curves which were found to be at low x/dh, and the subsequent upsurge and sustenance of the cooling effectiveness value of 0.45 at hole angles β = 30°, also flattens out, while hole angles β = 45° and hole angles β=90° show very similar values of η at more than x/dh =10 as in br=1.5. however, the performance of these three hole angles β=30°, β=45° and β=90°improves for values when compared to br=2.0. fig. 13c presents the br of 1.0. the result shows that the secondary hole angle β=30° offers the highest cooling effectiveness (η =0.48) of all the configurations at blowing ratio 2.0 and 1.5 with β=45° a3nd β=90° offering the least protection. the increased effectiveness values provided by the wider hole angle β=30° continue at distances downstream greater than x/dh 10. fig. 13d presents the br of a film cooling jet via a rectangular twisted hole of 0.5 improved the effectiveness of the film cooling. the findings offered the highest cooling effectiveness (η = 0.51) of all the configurations at br 2.0, 1.5 and 1.0 with β = 45° and β = 90° offering the least protection. the improvement in film cooling effectiveness was as a result of the interactions between the swirling film jet and the mainstream. the swirling motion was noted to have destroyed the kidney vortex structure and subsequently made the film-cooling air adhere to the wall. (a) (b) (c) (d) fig. 13 effectiveness against stream wise location at br equal to ((a) br= 2.0 (b) br=1.5 (c) br=1.0 (d) br=0.5) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 1 2 3 4 5 6 7 8 9 10 11 c o o li n g e ff e c ti v e n e ss x/dh β=30° β=45° β=90° 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 1 2 3 4 5 6 7 8 9 10 11 c o o li n g e ff e c ti v e n e ss x/dh β =30° β =45° β =30° 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 1 2 3 4 5 6 7 8 9 10 11 c o o li n g e ff e c ti v e n e ss x/dh β =30° β =45° β =90° 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 1 2 3 4 5 6 7 8 9 10 11 c o o li n g e ff e c ti v e n e ss x/dh β =30° β =45° β =90° al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 114 fig. 14 depicts the local averaged film cooling effectiveness performances for the rectangular twisted hole for diverse downstream locations and at varying brs of 0.5, 1.0, 1.5 and 2.0. the results demonstrated that at x/dh of 1.2, the higher value of the effectiveness of the film cooling performance generated by the rectangular twisted hole was superlative compared to the standard smooth hole. the difference in film cooling performance between the two film hole arrangements indicated an increase more with decreasing brs, as presented in figure. the downstream film cooling effectiveness decreased along the streamwise direction for both configurations until reach x/dh 11.0, owing to a decline in the momentum of the secondary flow. the averaged film cooling effectiveness performance of the rectangular twisted hole was still higher compared to the one generated by the circular hole at whole range of x/dh from 1.2-11.0, as depicted in fig. 16. at a high br of 2.0, the circular film hole provided a lateral film cooling performance near zero, as shown in figure 5.8d. (a) (b) (c) (d) fig. 14 spanwise film cooling effectiveness of the twisted hole at diverse brs (a) br = 0.5 (b) br = 1.0 (c) br = 1.5 (d) br = 2.0 fig. 15.a depict the heat transfer ratio with twisted angle 360° highest point at x/dh about ~ 2.0 near the injection hole. at lower br, the twisted film cooling holes produce variations in the magnitude of the thermal transfer ratio. however, it provides a lower value downstream. . the result shows offers the optimal heat transfer ratio (hf / h0 =1.8) of all the other br curves at 1.0, 1.5 and 2.0. the observed improvement emerged from the interactions between the swirling film jet, the mainstream as well as the swirling motion. fig. 15b shows the heat transfer ratio for the smooth rectangular shape hole highest point at x/dh which was about ~ 2.0, corresponding to the highest values in heat transfer ratio (hf / h0 =1.5). the 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -7.5 -6 -4.5 -3 -1.5 0 1.5 3 4.5 6 7.5 c o o li n g e ff e c ti v e n e ss z/dh x/d=1.0 x/d=3.0 x/dh =5.0 circular hole x/d=1.0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -7.5 -6 -4.5 -3 -1.5 0 1.5 3 4.5 6 7.5 c o o li n g e ff e c ti v e n e ss z/dh x/d=1.0 x/d=3.0 x/d=5.0 circular hole x/d=1.0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -7.5 -6 -4.5 -3 -1.5 0 1.5 3 4.5 6 7.5 c o o li n g e ff e c ti v e n e ss z/dh x/d=1.0 x/d=3.0 x/d=5.0 circular hole x/d=1.0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -7.5 -6 -4.5 -3 -1.5 0 1.5 3 4.5 6 7.5 c o o li n g e ff e c ti v e n e ss z/dh x/d=1.0 x/d=3.0 x/d=5.0 circular x/d=1.0 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 115 proposed scheme produces a value of the centerline heat transfer coefficient ratio higher than unity near the trailing edge of the film holes. this was as a result of the high velocity in the boundary layer with three dimensional flow structures, near the film hole. along the streamwise direction, the velocity decreases and gradually the flow become mainly two dimensional flow structures. (a) (b) figure 15 heat transfer coefficient ratio vs. stream wise location (a) α=360° (b) α=0° 4. development of new formula empirical correlations were commonly used to predict the nusselt number and laterally averaged adiabatic cooling effectiveness. they are mathematical formulations of different levels of complexity derived from experimental results and may cover ranges of flow as well as geometrical parameters. when selecting a correlation model, two important topics should be considered, one related to the limitations of the model and the other concerning the predictability of the model. ! = "(#$,%$,&,',)* the computer package (statistica) was used to make analysis for the equation through a nonlinear regression analysis. ! = +-(#$* ./(%$*.0(&*.1('*.2()*.3 c1= 0.0045, c2= -0.754, c3= 0.513, c4= 0.179, c5= 0.847 and c6=0.35 r 2 = 0.95 so, the equation becomes: ! = 4544678(#$*9:5;<>(%$*:5<-?(&*:5-;@('*:5a>;()*:5?< (9) the coefficient of determination (r 2 ) for this formula was (0.95). another data is used to test the equation. a statistical comparison of equations is used to show the predicted convergence to observed records. the value of r 2 = 0.931 were observed to be in good agreement for all data as shown in fig. 24. 0 0.5 1 1.5 2 2.5 3 0 1 2 3 4 5 6 7 8 9 10 11 h f / h 0 x/dh br=0.5 br=1.0 br=1.5 br=2.0 0 0.5 1 1.5 2 2.5 3 0 1 2 3 4 5 6 7 8 9 10 11 h f / h 0 x/dh br=0.5 br=1.0 br=1.5 br=2.0 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 116 fig. 16 comparison of equation (9) with experimental data the nu correlation was generated for the data obtained from the experimental results by using buckingham pi theorem. the correlation was compared with the findings of the experimental investigations in order to validate the ability of the correlation to predict the nu and the error was found within ±9.0 %. 5. conclusions in this study, a three case spirally corrugated film cooling holes (one, two and three holes) were experimentally and numerically evaluated to determine the effects of new twisted film cooling hole angle (α) and angle of hole (β) on thermal efficiency and/or performance. the findings of this study revealed that the adopted geometry of film cooling hole with smooth spiral corrugations can significantly improve effectiveness, ranging from 2.2–3.4 times those of the smooth film cooling holes with significant increase in the overall heat transfer coefficient ranging from 1.5–2.7 times those from smooth film cooling holes. the best thermal performance at twisted film cooling angle (α) equal to 360° and angle of hole (β) equal to 30° at blowing ratio equal to 0.5. based on the data obtained in this study, it was concluded that the most important factor in generating higher heat transfer coefficient as well as enhanced effectiveness lies in adopting and modified geometry of film cooling holes with smooth spirally corrugation profile which has to be optimized for greater efficiency. nomenclature symbol quantity units br blowing ratio (ρjuj/ρmum) cp specific heat w/kg.k dh hydraulic diameter of film hole (m) m dh hydraulic diameter of the main duct m dr density ratio (ρj/ρm) h heat transfer coefficient w/m 2 . k k thermal conductivity of plate w/m k l length of film hole m 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70 n u o b se rv e d nu predicted al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 117 nu nusselt number p film hole pitch m q heat transfer flux w/m 2 re reynolds number t temperature k t time s tw average wall temperature k um normal main stream velocity in x-direction m/s x, y, z coordinates ά thermal diffusivity m 2 /s η local film cooling effectiveness β angle of holes ° α angle of twisted holes ° references [1] z.s. kareem, m.n., mohd jaafar, t.m., lazima, a., f. abdulwahid, passive heat transfer enhancement review in corrugation, experimental thermal and fluid science. 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(93) (2016) 718–730. 4-4-2010.pdf 10-2-2011.pdf 112 channel coding is very important for secure communication. the most widely used communication coding is turbo coding technique, which is very secure technique. we deal in this paper with turbo code which is new class of convolutional codes. the performance of turbo code reaches the shanon limits in terms of bit error rate ber. to build the turbo code encoder we used two parallel concatinations of two recursive systematic convolutional codes (rsc) and the associated decoder which is using the feedback decoding rule. at low signal-to-noise ratio (snr), bit error rates (ber) of turbo code were obtained by simulation. turbo codes, pcccs, frame size, encoder memory size, iterative decoding . لجفرات . . اء ا اد (rsc). (ber)شانون بمعدل خطأ البت .(ber) في (snr). awgn: additive white gaussian noise (channel) ber: bit error rate icc: international conference on communication llr: log-likelihood ratio map: maximum a posteriori pcccs: parallel concatenation convolutional codes rsc: recursive systematic convolutional (code) . 113 the basis of informational revolution and its transformation to the power of the universe is dependent on the communications technology, its speed and security. the quality of information from source to destination should be the best. channel coding is a useful tool in the design of reliable digital communication. channel coding is necessary to improve error performance for digital communication system by mapping input sequences into code sequences which inserts redundancy and memory to the transmission. information theory states that arbitrarily small error rates are achievable provided the rate of transmission is less than the capacity of the channel. the gap between practical coding system and shannon’s theoretical limit closed even further in june 1993 at the international conference on communications (icc). at this conference two papers were presented that discussed a new class of codes and the associates decoding technique [1]. a very powerful channel coding scheme was developed by berrou, galvieux and thitmajshima, which used ideas related to both block and trellis codes. the encoding scheme uses simple convolutional codes separated by interleaving stages to produce generally low rate block codes. the decoding is done by decoding the convolutional encoder separately using log map algorithm and sharing bit reliability information in an iterative manner. this coding scheme is called turbo code and is found capable of achieving near shannon capacity performance, the theoretical limit [2]. this paper deals with achieved maximal information transfer over a limited-bandwidth communication link in the presence of data-corrupting noise. and the expected results that is when the numbers of decoder iterations increases, the performance of the code also increases, resulting in lower ber. a turbo code is the parallel concatenation convolutional codes (pcccs) of two or more component codes. in its original form, the constituent codes were from a subclass of convolutional codes known as recursive systematic convolutional (rsc) codes [1]. a generalized turbo encoder is known in the fig.1. in the figure, a data block u, which is k bits long enters the coders. the pad block appends n k tail bits to the data block, which yields the sequence x0. this n bit sequence is then fed in parallel into m sets of interleavers αi and encoders enci. each interleaver scrambles the x0 sequence in a pseudo-random fashion and feeds its output into a constituent encoder. each of the m constituent encoders presents a parity sequence xi at its output. the information sequence x0 together with the m parity sequences is concatenated to form the code word [3]. from the above discussion, it is clear that the turbo code encoder consists of two main parts: 1. a set of classical convolutional encoders. a set of interleavers. the basic rule of interleaver is to spread the residual error block of rectangular form which makes the decoding process stronger. the common practice of encoder is to use recursive systematic convolutional (rsc) encoders. by using a convolution encoder, it is possible for the decoder to utilize a modified version of the viterbi algorithm. recursive encoder is used as nonrecursive encoder will result in output codes with poor distance properties [4]. two identical rate 2/1 rsc encoders work on the input data in parallel as shown in fig.2. as shown in the figure, the input data is interleaved before being fed into the lower encoder. because the encoder is systematic (one of the outputs is the input itself) and receive the same input (although in different order), the systematic output of the lower encoder completely redundant and dose not need to be transmitted. the overall code rate of the parallel concatenated code is 3/1 , although 114 higher code rates can be obtained by puncturing (selectively removing outputs from the transmission stream) the parity output with a multiplexer (mux) circuit[5][6]. a burst of errors is defined as a sequence of bit errors. the method of interleaver has proved to increase the reliability in the burst error channel. in turbo code, the structure of interleaver has been carefully chosen. it allows that input sequences for which one encoder produces low weight codewords will usually cause the other encoder to produce high weight codewords. although the constituent codes are individually weak, the combination is surprisingly powerful [7][8]. it is a common practice to puncture the output of the encoder in order to increase the code rate to 1/2. for a rate 1/2 punctured turbo code, the first output stream is the input stream itself (plus the necessary padding), while the seconding output stream is generated by multiplexing the m nonsystematic output of the rsc encoders[9]. because turbo codes are linear block codes, the encoding operation can be viewed as the modulo-2 matrix multiplication of an information vector with a generator matrix. here the encoding a sequence by turbo code with the help of matrix representation is demonstrated. if the code generator matrix g = [1 1 1 ; 1 0 1], the rsc encoder will become as shown in fig.3. the encoder has constraint length of 3 with memory of 2 only. the encoding algorithm is similar to that of convolutional encoding. in order to generate a block code using a parallel concatenation of convolutional encoders, it is desirable for encoders to start and end in the all-zero state. to ensure this will happen, extra bits are needs to "clear" the memory of encoder. thus, the number of extra bits needed equals to the memory of encoder. in this example, 2 extra bits are needed. for an input u = [1 0 1], input uk state d1 state d2 feedback r output x1 1 0 0 1 1 0 1 0 1 1 1 1 1 1 0 0 1 1 0 1 1 0 1 0 1 0 0 therefore, output code c = [1 1 0 1 1] if a pseudo-random interleaver α with the mapping table as follow: l α(l) 1 2 2 5 3 4 4 1 5 3 the interleave function α (l) means the lth bit will take the α (l)th bit of the original code. the above table can also be represent by a interleaver matrix a = [2 5 4 1 3].with input u = [1 0 1 (0 1)], interleaver output = [0 1 0 1 1]. 115 then the turbo encoder become as shown in fig.(4): it is proposed that an iterative decoding scheme should be used. the decoding algorithm is similar to viterbi algorithm in the sense that it produces soft outputs. while the viterbi algorithm outputs either 0 or 1 for each estimated bit, the turbo code decoding algorithm outputs a continuous value of each bit estimate. while the goal of the viterbi decoder is to minimize the code word error by finding a maximum likelihood estimate of transmitted code word, the soft output decoding attempts to minimize bit error by estimating the posterior probabilities of individual bits of the code word. this decoding algorithm is called software decision viterbi decoding [10][12]. the turbo decoder consists of m elementary decoders, one for each encoder in turbo encoding part. each elementary decoder uses the software decision viterbi decoding to produce a software decision for each received bit. after an iteration of the decoding process, every elementary decoder shares its soft decision output with the other m 1 elementary decoders. it is clear that as the number of these iterations approaches infinity, the estimate at the output of decoder will approach the maximum a posteriori (map) solution. fig.(5) described the turbo code decoder. a log ratio of the posteriori probability of uk conditioned on the received signal y is defined as )/0( )/1( log)( 1 1 (1) the decoding decision of ~ is made based on the sign of l(uk), i.e., )(~ . (2) l(uk) is computed by three terms which are l_apriori, l_channel , and le(uk). l_apriori is a priori information based on the input bit uk at time k. it is provided by the previous decoder. l_channel is the received systematic bit at time k, referring to appendix a for details. ),’()( ~ )’(~ ),’()( ~ )’(~ log)()( 1 1 ,1 )(__ (3) where l_aprior and l_channel denote )( and ,1 respectively. u )( is the summation over all the possible transition branch pair (sk-1, sk) at time k given input uk=1 and u )( is the summation over all the possible transition branch pair (sk-1, sk) at time k given input uk=0. lc is the channel reliable factor; its computation is given as the following, _4 (4) 116 where a=1 for awgn channel, snr_b is the uncoded bit-energy-to-noise-ratio ( 0 ), p denotes 1/rc, rc is code rate of the turbo encoder. le(uk) is an extrinsic information based on all parity and systematic information except the systematic value at time k. it can be passed on to a subsequent decoder. it is computed using the following equations: )( ~ ),’()’(~ )( ~ ),’()’(~ log)( 1 1 (5) where 2 ,e 2 1 exp),’( . (6) )’( ~ ),(~ 1 can be computed recursively with initial conditions described below: . 0 1sif1 )(~ , ),’()’(~ ),’()’(~ )(~ 0 ’ 1 ’ 1 (7) . otherwise0 1sif1~ , ),’()’(~ ),’()( ~ )’( ~ ’ 12 1 (8) 2 ,1,1 2 1 exp 2 1 )( 2 1 exp),’( (9) for example, at any given iteration, decoder 1 )(1 is computed as )()()( 1221 ,1 1 (10) ])(sign[l~ 1 where )(1 is given in equation (3). )(21 is extrinsic information for decoder 1 derived from decoder 2, and )(12 is the third term in equation (3) which is used as the extrinsic information 117 for decoder 2 derived from decoder 1. the decoders are sharing the information with each other. the value of l1(uk) decides the degree of the reliability of ~ . the performance of turbo code rate ½ rsc component code for various numbers of decoder iterations is shown in figure 6. in this figure, it can be seen that as the numbers of decoder iterations increases, the performance of the code also increases, resulting in lower ber. figure 7 and figure 8 show the simulated performance results for two specific cases. in figure 7, the turbo code with rate 1/3 and in figure 8 the rate is ½ with the same constraint length and the numbers of decoding iterations, the difference between the simulated performance results is negligible for high bit energy to noise power spectral density eb/no (snr>2), but for lower eb/no (snr<2), this difference becomes greater. turbo coding technique has great potentials in achieving communications at very low values of / for awgn channel. the performance of turbo codes depends on the interleaver design which is embedded in the parallel encoder. to get lower bit error rate we need large interleaver size which leads to longer decoding delay. general analytical upper bounds and design rules for concatenated codes with interleavers over awgn channel were presented. mutual information between transmitted systematic bits and extrinsic output of constituent decoders was found to be a useful measure for gaining insight into the convergence behavior of iterative decoding. [1] c. berrou, a. glavieux, and p. thitimasjshima, "near shannon limit error-correcting coding and decoding: turbo-codes (1)," in proc., ieee int. conf. on commun., pp. 1064-70, may 1993. [2] m. c. valenti, “iterative detection and decoding for wireless communications”, ph.d. thesis, virginia polytechnic institute and state university, july 8, 1999. [3] h. h. abbas, “simulation of turbo-encoder-decoder performance. ph.d. thesis, baghdad university, oct. 2001. [4] s. benedetto, d. divsalar, d. montorsi, and f. pollara, “a soft-input soft-output maximum a posteriori (map) module to decode parallel and serial concatenated codes”, tda progress report 42-127, november 15, 1996. [5] m. c. valenti, “turbo codes and iterative processing”, proc. ieee new zealand wireless communication symposium 98, nov.1998. [6] kuhn and desmond, “near-shannon-limit channel coding using woven convolutional codes”, melbourne university, nov. 13, 2000. [7] jian qi "turbo code in is-2000 code division multiple access communications under fading” m.sc. thesis, wichita state university, 1999. [8] s. benedetto and g. montorsi, "generalized concatenated codes with interleavers," in proc., int. symp. on turbo codes and related topics, (brest, france), pp. 32-9, sept. 1997. [9] y. yasuda, k. kashiki, and y.hirata, “high-rate punctured convolutional codes for soft decision viterbi decoding,” ieee trans. commun. vol. com.-32, pp.315-319, march 1984. 118 [10] j. cheng, “iterative decoding”, ph. d, thesis, california iinstitute of technology, pasadena california, 1997. [11] s. a. barbulescu, “iterative decoding of turbo codes and other concatenated codes”, univ. of south australia, feb. 1996. [12] marius oltean, maria kovaci, horia balta andrei and campeanu, “multy binary turbo coded wofdm performance in flat rayleigh fading channels”, acta technica napocensis electronics and telecommunications, volume 49, number 3, 2008. 119 0 1 )(1 ,1 )’(12 ’ ,1’ ~ )’(21 )(21 )(12 map decode1 m ap decode2 -1 add tail bits drop tail bits add 0 at tails drop tail bi ts make hard decision is the notation for interleaver, -1 is the notation for de-interleaver. fig.5. block diagram of turbo decoder 120 fig.6. simulated performance of a rate r=1/2, constraint length =5, turbo code for various numbers of decoder iterations. the size of interleaver is =65,536 and an awgn channel is assumed. fig.7. bit error rate vs. as parameterized by frame size for turbo code with rate 1/3, constraint length 3, and 8 iterations of improved decoding over an awgn channel. 121 fig.8. bit error rate vs. as parameterized by frame size for turbo code with rate 1/2, constraint length 3, and 8 iterations of improved decoding over an awgn channel. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 estimating delay time at palestine street intersections in baghdad city using hcm and sidra models assist. lecturer abeer k. jameel highway & transportation eng. dept, college of engineering, university of almustansiriy abstract the objective of this paper is to the estimate delay time at two important intersections in baghdad city using highway capacity manual model (hcm) ,which is widely used for estimating delay at signalized intersections in iraq, and signalized and unsignalized intersection design and research aid (sidra intersection 4) model. field traffic volumes and control delay were measured during peak and off-peak periods. data on geometric design elements and signal timings and phasing were measured through a field survey. the results of the analysis indicated that sidra interswction4 using hcm model was found to be the best in the comparison with the field values by observed percent of difference. therefore a proposed model is build by derive a new parameters of the uniform delay term (d1) and random delay term (d2) for non-lane state. this model is validated on art college intersection. the results show that the predicted model cannot be used for other intersections. then a proposed model is build for art college intersection. keywords: hcs, hcm, sidra, sidra intersection4, signalized intersections, delay. hcm موديالت تخمين زمن التأخير في تقاطعات شارع فلسطين في مدينة بغداد باستخدام sidra و المدرس المساعد عبير خضر جميل قسم هندسة الطرق النقل الجامعة المستنصرية/ كلية الهندسة الخالصة ، )hcm(سعة الطرق يموديل اد باستخدام في تقاطعين مهمين في مدينة بغد قيم زمن التأخيرتخمين هوهذا البحث الهدف من sidra( و في العراق،في التقاطعات العاملة بنظام االشارة الضوئية في تخمين قيم زمن التأخيرامه دالشائع استخ intersection 4( . تم مسح الحجوم المرورية وقيم زمن التأخير الحقلية في موقع التقاطعات في ساعات الذروة أن نتائج التحليل بينت . مسح الخصائص الهندسية وعناصر زمن الدورة الضوئية وأطوارها لكل تقاطعوتم أيضاً. غيرهاو أعطى أفضل النتائج بعد المقارنة مع القيم الحقلية (hcm)باستخدام موديل ) (sidra intersection 4برنامج ومتغير زمن (d1)ة لمتغير زمن التأخير المنتظم ديديل بمعايير جد لذلك تم استنباط مو. بنسبة اختالف واضحةلزمن التأخير يل بتطبيقه في حساب زمن التأخير في دقيق صحة النتائج لهذاالمودتم ت. لحالة جريان غير منتظمة(d2)التأخير العشوائي القة أخرى لتقاطع لذا تم استنباط ع. يل اليمكن تطبيقه على تقاطعات أخرىدبينت النتائج ان المو. تقاطع كلية الفنون الجميلة . الفنون الجميل 614 introduction vehicle delay is the most important parameter used by transportation professionals to measure the performance of signalized intersections. this importance of vehicle delay is reflected in the use of this parameter in both design and evaluation practices. for example, delay minimization is frequently used as a primary optimization criterion when determining the operating parameters of traffic signals at isolated and coordinated intersections (garber and hoel 1997). the highway capacity manual (trb 2000) further uses the average control delay incurred by vehicles at intersection approaches as a base for determining the level of service provided by the traffic signals located at the downstream end of the these approaches. the popularity of delay as an optimization and evaluation criterion is attributed to its direct relation to what motorists experience while attempting to cross an intersection. however, delay is also a parameter that is not easily determined, for instance, indicated that a perfect match between field-measured delay and analytical formulas could not be expected. the difficulty in estimating vehicle delay at signalized intersections is also demonstrated by the variety of delay models for signalized intersections that have been proposed over the years (garber and hoel 1997). despite differences between the proposed delay models, very little research has been concerned with the consistency of delay estimates from one model to the other. this paper addresses this problem by comparing the delays that are estimated by analytical delay models with that computed from the field. to achieve this goal, the paper first presents some background material on vehicle delays at signalized intersection, followed by a description of the two famous delay models that are being compared (hcs and sidra models). evaluations of the consistency of delay estimates from these models are conducted by using them to evaluate delays on both under-saturated and over-saturated signalized intersection approaches. then proposed model is build to compute the delay time at signalized intersection. delay time measurement delay is the time lost while traffic is impeded by elements over which the driver has no control. delay results from two factors (garber and hoel 1997): aoperation delay: it may be caused by interference between and within traffic streams. bfixed delay: it is caused by traffic control devices. delay time types there are several types of delay that can be measured at an intersection, and each serves a different purpose to the transportation engineer. intersection delays may include two components: queue delay and control delay. queue delay, or stop delay, is difficult to quantify due to its stochastic nature affected by random arrivals. sophisticated techniques may work better in estimating queue delays, but are often impractical for planning models due to intense data requirements. it is often difficult to find a well-balanced queue delay model for integration into a planning model. the signalized intersection capacity and los estimation procedures are built around the concept of average control delay per vehicle. control delay is the portion of the total delay attributed to traffic signal operation for signalized intersections (trb 2000) and (ding 2007). control delay (overall delay) can be categorized into deceleration delay, stopped delay and acceleration delay (trb 2000): astopped delay is easier to measure, typically, transportation professionals define stopped delay as the delay incurred when a vehicle is fully immobilized, bthe delay incurred by a decelerating or accelerating vehicle is categorized as deceleration and acceleration delay, respectively. 615 in hcm2000 (trb 2000), control delay is comprised of initial deceleration delay, queue moveup time, stopped delay, and final acceleration delay, though in earlier versions it included only stopped delay. besides the control delay, there is another type of delay which vehicles experienced at signalized intersection. this type of delay is identified as geometric delay which is the time lost due to the intersection geometry. geometric delays may be large for turning movements. total delay of a vehicle is the sum of control delay and geometric delay (darma etal 2005). delay time measurement methods two methods have been used to measure the delay time at signalized intersection, field measurement and theoretical measurement. field measurement there are a number of techniques for making field measurement of control delay, including the use of test-car observations, path tracing of individual vehicles, and the recording of arrival and departure volumes on a cycle-by-cycle basis. for oversaturated conditions, other methods may be considered, such as an input-output technique or a zoned-survey technique. in the input-output technique, different observers count arrivals separately from departures and vehicles in queue are calculated as the accumulated difference, subject to in-process checks for vehicles leaving the queue before they reach the stop line. the zoned-survey technique requires subdividing the approach into manageable segments to which the observers are assigned; they then count queued vehicles in their assigned zone. both of these techniques require more personnel and are more complicated in setup and execution(trb 2000). hcm field delay measurement method is applicable to situations in which queues are long or the demand to capacity ratio is near 1.0 with care must be taken to continue the vehicle-in-queue count past the end of the arrival count period. the method does not directly measure delay during deceleration and during a portion of acceleration, which are very difficult to measure without sophisticated tracking equipment. however, this method has been shown to yield a reasonable estimate of control delay. the method includes an adjustment for errors that may occur when this type of sampling technique is used, as well as an acceleration-deceleration delay correction factor. the acceleration-deceleration factor is a function of the typical number of vehicles in queue during each cycle and the normal free-flow speed when vehicles are unimpeded by the signal( trb 2000). figure (1) show a worksheet that can be used for recording observations and computation of average time-in-queue delay. more details about the procedure that has been used in collect field control delay at signalized intersection are explained in appendix a at highway capacity manual hcm 2000(trb 2000). theoretical method several models for estimating vehicle delay at signalized intersections have been used. however, it seems that the exploration on the method for estimating the delay is still continuously conducted. this is may be due to the consideration of various variables which could affect the delays. the change of the primary factor for measuring the los at signalized intersection from stopped delay (hcm1994) to control delay (hcm1997 and 2000) depicts the continuing improvement by incorporating current research findings (darma etal 2005) and (hadiuzzaman 2008) . the research of traffic engineering design several models, dion et al (dion et al 2004) and akgungor (akgungor & bullen 2007) illustrated five delay models for signalized intersection: deterministic queuing model, shock wave delay model, steady-state stochastic delay model (for example webster model(pretorius etal 2004)) , time-dependent stochastic delay model (xuegang etal model (xuegang etal 2008) and kimber and hollis model (pretorius etal 2004), and finally, 616 microscopic simulation delay model (like transyt and corisim models) (rahim etal 2001) and (pretorius etal 2004). webster classical formula is the oldest and the most popular deterministic model, which has been originated in uk. numerous studies were conducted in the field of estimating delays at signalized intersections that a result of them, a number of delay models based on deterministic queuing theory were proposed to suite different field conditions (luttinen 2003). among these, the most notable are the models developed by miller (1963) and akcelik (1981) in australia, the models developed for use in hcm 1985 (trb 1985), hcm 1994 (trb 1994) and hcm 2000 (trb 2000) in united states, the model developed by teply et al. (1995) in canada, and sierpiński model (sierpiński & janusz 2007). however, these models are analytically superior to webster’s classical model in the sense that they can successfully deal with oversaturated conditions and the effect of progression and platooning (shamsul and asif 2007) and (ding 2007). highway capacity model hcm 2000 (trb 2000) model is the most widely used in iraq and the world. other models are used also, for example sidra (akçelikl 2009) and transyt models. highway capacity manual (hcm2000) model highway capacity manual (hcm2000) (trb 2000) is widely used for the design of signalized intersection in north america and other developed countries. in this manual, control delay is the principal service measure for evaluating los at signalized and unsignalized intersections. control delay involves movements at slower speeds and stops on intersection approaches, as vehicles move up in the queue or slow down upstream of an intersection (trb 2000). hcm and other works assume homogeneous and lane based traffic for analysis, which exists in those countries, but traffic flow in countries like iraq consists of different classes of vehicles having no lane disciplined. the capacity analysis method for signals in this manual is the most recent edition since the procedure was converted from a v/c-based to a delay-based method in the hcm85, and has retained basically the same fundamental delay model since. the delay computation procedure, founded on the webster delay model developed in 1958, which has stood the test of time as a fundamental method for traffic signal analysis. the delay model is comprised of two elements (dennis etal 2006): 1. “the first term” (d1): produces the average delay per vehicle in the average cycle, assuming that traffic arrivals and departures are completely uniform, both within each signal cycle and across all cycles during the analysis period. 2. “the second term” (d2): produces the incremental delay due to randomness in arrivals from cycle to cycle. the incremental delay assumes steady state conditions. several structural changes (with significant impact) have been made that resulted in the methods employed by the 1985 and subsequent updates of the hcm (1994, 1997, and 2000), but the basic structure of the method has remained unchanged. these changes are explained in ((dennis etal 2006): in the hcm 2000, the average delay per vehicle for a lane group is given by equations 1 to 4 (hcm 2000) (trb 2000). d = d1(pf) + d2 + d3 (1) where d = control delay per vehicle (s/veh); d1 = uniform control delay assuming uniform arrivals (s/veh); pf = uniform delay progression adjustment factor, which accounts for effects of signal progression; 617 d2 = incremental delay to account for effect of random arrivals and oversaturation queues, adjusted for duration of analysis period and type of signal control; this delay component assumes that there is no initialqueue for lane group at start of analysis period (s/veh); and d3 = initial queue delay, which accounts for delay to all vehicles in analysis period due to initial queue at start of analysis period (s/veh). where pf = progression adjustment factor, p = proportion of vehicles arriving on green, g/c=proportion of green time available, and fpa = supplemental adjustment factor for platoon arriving during green. where: d1 = uniform control delay assuming uniform arrivals (s/veh); c = cycle length (s); cycle length used in pretimed signal control, or average cycle length for actuated control (see appendix b for signal timing estimation of actuated control parameters); g = effective green time for lane group (s); green time used in pretimed signal control, or average lane group effective green time for actuated control , and x = v/c ratio or degree of saturation for lane group. where d2 = incremental delay to account for effect of random and oversaturation queues, adjusted for duration of analysis period and type of signal control (s/veh); this delay component assumes that there is no initial queue for lane group at start of analysis period; t = duration of analysis period (h); k = incremental delay factor that is dependent on controller settings; i=upstream filtering/metering adjustment factor; c = lane group capacity (veh/h); and x = lane group v/c ratio or degree of saturation. d3 =(1800qb(1 + u)t) /ct (5) where qb=initial queue at the start of period t (veh), c=adjusted lane group capacity (veh/h), t = duration of analysis period (h), t = duration of unmet demand in t (h), and u = delay parameter the details of these calculation have been shown in chapter 16 at highway capacity manual 2000 (trb 2000). 618 the signalized and unsignalized intersection design and research aid (sidra) model (sidra) software (akçelikl 2009) used as an aid for design and evaluation of signalized intersection (fixed-time/pretimed and actuated), roundabouts, two-way stop sign control, all-way stop sign control, and give-way (yield) sign-control (al-omari and ta’amneh 2007) . sidra uses detailed analytical traffic models coupled with an iterative approximation method to provide estimates of capacity and performance analyzes signalized and unsignalized intersections and roundabouts. it computes average control delay, geometric delay, level of saturation, and level of service (sabra etal 2000). this software is compatible with the us highway capacity manual (hcm) to a good extent. the us hcm versions of sidra intersection do not claim to be a simple replication of the hcm procedures. this means that generally (for all types of intersection), sidra intersection4 uses more advanced models and methods, including lane-by-lane analysis rather than analysis by lane groups, modeling of short lanes, detailed modeling of geometric delays, and the use of drive cycles (cruise, acceleration, deceleration and idling) for detailed modeling of delay and travel time components as well as operating cost, fuel consumption and emission estimation. a key construct used in developing the sidra intersection delay definitions given above was a clarification of whether the delay estimated by a traditional analytical delay model includes any acceleration and deceleration delays. the sidra intersection method assumes that the analytical model delay is a stop-line delay that includes the main stop-start delay to queued vehicles, and does not include the geometric delay. in determining control delay for individual movements, control delay values for the lanes used by the movement are not aggregated directly. the stop-line delay values for the lanes used by the movement are aggregated first, and then the geometric delay for the movement is added. geometric delay and other statistics for movements combined using the same movement number are the flow-weighted average values for individual origin-destination movements. the use of control delay (overall delay with geometric delay) is the recommended method for consistency in comparing alternative intersection treatments. stop-line delay given in the lane delays table in the detailed output report is recommended only for comparison of sidra intersection results with those from software packages that estimate delay without the geometric delay, or when the survey method used produces a delay that does not include the geometric delay. the delay models used by sidra intersection when the hcm delay option is applicable (model defaults-model general) differ from the standard sidra intersection models although the model structures are similar. for signal coordination (platooned arrivals), the hcm progression factor method is used for delay prediction. in sidra intersection, an additional progression factor is used for the prediction of queue-related performance statistics. the color code used for movements in the control delay display under movement displays is based on the level of service (los) values as indicated by the legend of the display more details about the sidra models in sidra intersection4 user guide (akçelikl 2009) and (abdy 2000), and more details in the differences between hcs and sidra packages are studied by (freeman etal 1999), (petraglia 1999), (abdy 2000), (transportation research board / national research council 2000), (turley 2007), and (darma 2005). objectives and scope the specific objectives of this paper are summarized as follows: 1estimation delay time at palestine street intersections in baghdad city based on field delay data and using two software (hcs and sidra models) , and determine the most suitable software which represents the baghdad conditions in estimating the signalized intersection delay, 2find out delay time model, which represent palestine street intersections in baghdad city conditions. 3validate this model by using it in the estimating of delay time at art college intersection in baghdad city. 619 study area selection three signalized intersections were selected at two important locations in baghdad city to perform this study. they are palestine street intersections (palestine intersection 1 and 2), and art college intersection. the study area that were selected for this study in baghdad city, that’s palestine street and al-wazeria have high degree of important and the characterized as cbd area. figure 2 and figure 3 show the satellite image of the area study. data collection beside of the field delay time, the basic data that collected for calculating theoretical delay time are categorized into three categories: geometric, volume, and phasing signal. geometric data the details of lane geometric include number of lanes, lane widths, existing and location of curb parking lanes and bus stops. table 1 shows the existing the geometric conditions of the selected sites. traffic volume data traffic volumes for the intersections must be specified for each movement on each approach. data are gathered during weekday and clear weather for all the intersection of the selected sites .the period of the volume counting was divided into 15-minute intervals distributed over the best time of data counting. the vehicles volume surveys are classified into two types: 1. small vehicles: any vehicles move on four wheels includes the pc. 2. large vehicles: any vehicles move on more than four wheels. because the two models are not considered the variety in large vehicle capacity, then the small passenger car equivalent to large vehicle is calculated manually at each of the selected intersection with equivalent factor of 1.5 for large vehicle with average capacity of 20 pass/veh and 2 for truck vehicles and buses of more than 40 pass/veh. table 1 shows the existing the traffic conditions of the selected sites.at peak and off peak periods. signal phasing and timing in baghdad city, to control the traffic, fixed time traffic signals are being used for a significant number of years. unfortunately, rather than using any traffic engineering knowledge, these signals have been timed by traffic police from arbitrary judgment only. as a result, they became ineffective to serve the purpose properly and efficiently. therefore, this research assumed that the selected intersection work actuated system by traffic police and four phases signals (each approach with one phase) and use the maximum actual green time, that are assumed as a default value in sidra model, equal to 50 second. field delay time measurement table (2) show a sample of field delay time survey at palestine intersection, and figure 4 to 9 show the field measurement at the selected intersection at peak and off peak periods. it should be noticed that field delay measurements were conducted for under-saturated, saturated, and oversaturated traffic flow conditions to be consistent with the hcm standard method of field delay data measurement. estimating of theoritical delay time the collected traffic, geometric and timing data were used as inputs to the hcs and sidra software and the control delay was obtained. figure 4 to 9 show these results by bar chart graphics. past research investigated different approaches for studying the uncertainty of the hcm delay model caused by uncertainty in input variables by several methods (xiaojin 2006). 620 in this paper, the software results were compared with the measured field control delay using graphs, regression analysis and paired t-test. graphical comparison this method of statically comparison has been used in many research to validate the theoretical models results with the actual value (al-omari 2007), (michael etal 2000), and (shamsul & imran 2007). in order to verify hcm and sidra models, the field control delay, as resulted in hcs and sidra intersection4 software, were plotted against the actual control delay time produced from the field. a regression line was fitted through the data points. note that such plots were constructed for each theoretical model, the results of calculation for the three intersections at peak and off peak hours with the graphical comparison of those with field-measured delay are shown in figures 4 to 9, and the results of the degree of saturation (v/c) calculation with the graphical comparison delay are shown in figures 10 to 15. figure 16 show the relationship between the theoretical delay that are calculated by the three models with the degree of saturation (v/c). it is noted that the theoretical models are nearly present equal values of delay when v/c is less than (1.0) and trend to be different at slightly higher value when v/c is greater than (1.0). figure 17 show the relationship between the differences between the theoretical delay that are calculated by the three models and field delay with the degree of saturation (v/c). it is noted that hcm model using sidra has smaller difference from field measurement in delay value than hcm model using hcs and sidra model in all values of v/c. in general all models gives high difference range when v/c is greater than (1.0). figure 18 presents the graphical comparison between the field delay and hcs model, from these results it can be seen that, for field delay ranges up to 80 seconds, hcs tends to be equal to estimate control delay. for higher delay ranges, it has under-estimations. figure 19 presents the graphical comparison with theoretical delay which is calculated by sidra intersection4 using hcm model and its defaults value and figure 20 presents the graphical comparison with theoretical delay, which is calculated by sidra intersection4 using sidra model and defaults value. in this figures, it can be seen that, for delay ranges up to 50 seconds, sidra delay value has a good estimation of the control delay. in the range of (50 to 200) sec/veh, sidra has mix of under-estimations and over-estimations with some points that are severely over-estimated. sidra delay value has a severely over-estimated in the range greater than 200sec/veh. regression analysis the measured field delays were regressed against the predicted models producing the results shown in table 3. from this table it is observed that sidra model gives lower value of r2 and higher standard error of estimation (see) while hcm model using sidra intersection4 gives higher value of r2 and lower value of (see). paired t-test the paired t-test results, as shown in table 4, showed the mean of differences with a p-value. it was also used to see if the average deviations between filed and predicted control delay are significantly far from zero. these results shows the hcm model using hcs have less standard deviation and standard error mean from the field delay with p value equal to 0.00. 621 software calibration the basic saturation flow rate was measured following the hcm standard procedure (trb 2000) using the through movement on the intersection approaches that were believed to be the closest to ideal conditions. so a calibration was conducted for the hcs (which has a default value of 1900 pcphgpl) and sidra intersection4 software (which has a default value of 1900 pcphgpl for hcm model and 1950 pcphpgl for sidra model) regarding the basic saturation flow rate. in this paper the basic saturation flow rate was averaged to values greater than the default value of the models but not higher than 2300pcphpgl which is the maximum saturation flow value for hcs. this high value can be explained by knowing the aggressive driver behavior in iraq which results in reducing the vehicle headways leading to an increase in the saturation flow rate. the field delays were regressed against the predicted ones, producing the results shown in table 5. at all values of v/c the r² value indicated that hcs explains about 66.5% of the variability in the control delay at saturation flow equal to 2000 pcphpgl. this is higher than the r² value obtained using default values by 4%. while the default value gives the higher r2 at under and over saturation state. the r² value indicated that sidra intersectio4/hcm model explains about 76.6% of the variability in the control delay at default value of saturation flow. this is higher than the r² value obtained using values greater than it. while the saturation flow of 2200pcphpgl gives the higher r2 at under and over saturation state. when using sidra intersectio4 / sidra model, the r² value indicated that 69%% of the variability in the control delay at default value of saturation flow. this is higher than the r² value obtained using default value by 10%. while the saturation flow of 2300pcphpgl gives the higher r2 at under and over saturation state. building of delay time model estimation of delay at signalized intersections is a complex process and depends on a number of parameters, among which the degree of saturation (x = v/c) is the most important (akgungor 2007). the urban road traffic situation of baghdad city is quite different from that of developed city. the traffic is mixed with a wide variation in the operating and performance characteristics of vehicles. the vehicles which travel in the same right of way also vary in size, maneuverability, control and dynamic characteristics. another striking feature of the road traffic operating condition is that most of the time lane discipline is not followed no matter whether non-motorised vehicles are present or not. at intersections, there is notable lateral movement and vehicles tend to use lateral gaps to reach the front of the queue. hcm 2000 delay model takes into account effect of signal coordination and uncoordinated surrounding intersections and is selected to modify in order to be able to estimate control delay for non lane based traffic condition. details about hcm 2000 equation are shown above. control delay which includes initial deceleration delay, queue move-up time, stopped delay, and final acceleration delay is given by: d = d1(pf) + d2 + d3 (1) past studies (al-omari 2007), starting time survey is selected in such a way that there is no residual delay and hence d3 is zero. for the purpose of regression analysis above delay equation can be written as: df = ax1 + bx2 (6) where, df = field delay, x1 = d1 * pf, x2 = d2/900, a and b = calibration parameters. to find suitable value of constant in the equation for d1and d2 which are currently 1 and 900 respectively, delay estimation equation has been proposed based on regression analysis. 622 proposed delay model along with statistics is build with input field control delay time of two selected intersection , palestine intersection (1) and (2) because they have the same conditions. the proposed model is: d = 1.43161 + 0.75301d1 + 241.446d2 (7) and the statistical analysis results of the model are shown in table (6). this results shows that since the p-value is less than 0.01, there is a statistically significant relationship between the variables at the 99% confidence level. the r-squared statistic indicates that the model as fitted explains 86.6241% of the variability in actual control delay time. the adjusted r-squared statistic, which is more suitable for comparing models with different numbers of independent variables, is 84.1921%. the standard error of the estimate shows the standard deviation of the residuals to be 28.1029 validation of the proposed model in order to validate the proposed model of control delay time prediction at palestine street intersection at another site, the input parameters of art college intersection are used to investigate the estimated delay time at it. the results of the validation are shown in table (6). conclusions and recommendations the basic concluded remarks are as follow: 1. the results of the analysis showed that hcm model using hcs and sidraintersection4 with hcm model give a predicted control delay that is best agreement with the field data that sidra model. 2. on the other hand, the hcm model gives different delay time values when using hcs than sidra intersection4 with hcm model by a small percent. 3. it was found that the sidra model can be improved significantly and used for traffic analysis in baghdad conditions by calibrating the basic saturation flow rate. 4. this study showed that traffic software, which are being used in the developed countries, should not be used in iraq or other developing countries before calibrating their parameters that are believed to be different from those in developed countries such as the ones related to driver behavior. 5. a proposed model is build by derive a new parameters of the uniform delay term (d1) and random delay term (d2) for non-lane state. this model is validated on art college intersection. the results show that the predicted model cannot be used for other intersections. then a proposed model is build for art college intersection. references abdy zeeshan raza, “sidra calibration, validation and comparison with transyt 7f”, http://faculty.kfupm.edu.sa/ce/nratrout/ce%20675-031-sidra%20and%20trsnsyt.pdf, 2000. akçelik, r., “sidra intersection user guide”, victoria, australia. 2009. akgungor a. payıdar and bullen, a. graham r., “a new delay parameter for variable traffic flows at signalized intersections”, turkish j. eng. env. sci.31 (2007) ,pp 61 – 70. al-omari b. h. and ta’amneh m. m., “validating hcs and sidra software for estimating delay at signalized intersections in jordan”, jordan journal of civil engineering, volume 1, no. 4, 2007 (375-392). http://faculty.kfupm.edu.sa/ce/nratrout/ce%20675-031-sidra%20and%20trsnsyt.pdf 623 darma yusria, mohamed r. k. , jamilah m. , and sulaiman a. “control delay variability at signalized intersection based on hcm method”, proceedings of the eastern asia society for transportation studies, vol. 5, pp. 945 958, 2005. dennis w. strong, nagui m. rouphail, ken courage , “new calculation method for existing and extended hcm delay estimation procedures”, paper submitted to the 85th annual meeting of the transportation research board, washington, dc, january 2006. ding zhen, “a static traffic assignment model combined with an artifficial neuralnetwork delay model”, a doctorate dissertation submitted to florida international university miami, florida 2007. dion f., rakha h., and kang y. “comparison of delay estimates at under-saturated and oversaturated pre-timed signalized intersections”. transportation research, part b, 38, 99–122, 2004. freeman walter j., kien y. ho, mcchesney elizabeth a., “an evaluation of signalized intersection system analysis techniques”, copyright ite annual meeting cd, http:// www.trafficware.com/documents/1999/00055.pdf, 1999. garber, n.j.,and hoel, l.a.”traffic and highway engineering.”, 2nd edition, 1997. hadiuzzaman md., “development of saturation flow and delay models for signalized intersection in dhaka city”, thesis submitted to department of civil engineering/bangladesh university of engineering and technology, january, 2008. luttinen r. tapio “delays at signalized intersections: a comparison of capcal 2, dankap, and hcm2000”, paper no. 03-3613, transportation research board, washington, d.c., 82nd annual meeting, january 12-16, 2003. michael j. pacelli, carroll j. messer p.e., and thomas urbanik ii p.e., “development of an actuated traffic control process utilizing real-time estimated volume feedback”, report 143910, project number 0-1439, research project title: txdot support of the texas a&m ivhs research center of excellence, sponsored bytexas department of transportation in cooperation with the federal highway administration, u.s. department of transportation.september 2000. petraglia kenneth j., “field validation of moe’s for signalized intersection analysis”, copyright ite annual meeting cd. http://trafficware.infopop.cc/downloads/00058.pdf 1999 . pretorius, p., van as. and troutbeck, r.j.,” issues with the operational analysis of urban intersections” , 23rd annual southern african transport conference 2004. rahim f. benekohal, yoassry m. elzohairy, joshua e. saak, “comparison of delays from hcm, synchro, passer ii,passer iv and corsim for an urban arterial”, transportation engineering series no. 113, traffic operations lab series no. 1, august 2001. sabra z.. wallace c. e., and lin f., “national research council traffic analysis software tools”, transportation research board 2000. shamsul hoque and asif imran, “ modification of webster’s delay formula under non-lane based heterogeneous road traffic condition”, journal of civil engineering (ieb), 35 (2) (2007) 81-92. http://www.trafficware.com/documents/1999/00055.pdf http://trafficware.infopop.cc/downloads/00058.pdf 624 sierpiński g., janusz w., “proposition of delay model for signalized intersections with queueing theory analytical models usage”, transport problems international scientific journal. volume 4, issue 4, gliwice 2007, pp. 49-56. transportation research board (trb), highway capacity manual. national research council. washington, d.c. ,2000. transportation research board / national research council, “circular, traffic analysis software tools”, number e-co14, september 2000. turley carole,“calibration procedure for a microscopic traffic simulation model”, master thesis submitted to the department of civil and environmental engineering ,the faculty of brigham young university,april 2007. xuegang j. b., ryan h., alexandre m. bayen, “delay pattern estimation for signalized intersections using sampled travel times”, 88th annual meeting of transportation research board, august 01, 2008. xiaojin j. ji and panos d. prevedouros, “probabilistic analysis of hcm delay for signalized intersections”, annual meeting of the trb, transportation research record, 2006. . 625 table *(1) existing traffic and roadway condition of selected intersection at peak hour* off peak hour* lane width (ft.) no. of lanes phf* volume (vph) (lv+1.5mv+2.0hv) phf* volume (vph) (lv+1.5mv+2.0hv) palestine intersection (1) l 11 1 0.90 505 0.90 288 t 11 3 0.91 862 0.95 329 north bound r 11 1 0.90 798 0.92 128 l 11 1 0.83 359 0.97 424 t 11 3 0.91 1001 0.94 643 south bound r 11 1 0.95 445 0.92 330 l 13 1 0.84 723 0.82 567 t 13 3 0.95 4507 0.89 1690 east bound r 13 1 0.96 873 0.91 657 l 13 1 0.92 589 0.89 789 t 13 3 0.92 2302 0.85 889 west bound r 13 1 0.93 389 0.85 272 palestine intersection (2) l 12 1 0.92 631 0.94 265 t 12 3 0.90 3121 0.92 1040 north bound r 12 1 0.94 451 0.93 256 l 12 1 0.88 637 0.96 270 t 12 3 0.92 3039 0.92 1119 south bound r 12 1 0.88 3332 0.86 1203 l 11 1 0.86 728 0.96 174 t 11 3 0.92 866 0.80 427 east bound r 11 1 0.93 436 0.94 279 l 11 1 0.90 197 0.92 66 t 11 3 0.94 178 0.91 117 west bound r 11 1 0.94 154 0.90 86 art college intersection l 12 4 0.95 916 0.95 768 t 12 4 0.95 894 0.95 720 north bound r 12 4 0.95 372 0.95 232 l 12 4 0.94 141 0.94 101 t 12 4 0.94 1211 0.94 988 south bound r 12 4 0.94 361 0.94 243 l 12 4 0.97 657 0.97 468 t 12 4 0.97 1006 0.97 925 east bound r 12 4 0.97 368 0.97 220 l 12 4 0.98 720 0.98 567 t 12 4 0.98 593 0.98 444 west bound r 12 4 0.98 1180 0.98 897 *note. no percent of grade, pedestrain flow in each approach assumed 50 ped/hr., no pedestrian button, no existing of curb parking lanes; storage bays, and buses stops. phf =phv/4(highest volume/interval of 15min.) , peak hour is: 8:00-9:00 am for palestine street intersections and 7:45-8:45 am for art college intersection off peak hours: 11:15am-12:15 pm for palestine street intersections and 11:00am -12:00 pm for art college intersection 626 table (2), sample of the results of delay survey input field data n(no. o lane)=5 vstop=161 , vtot=161 , is=15sec. , no of veh. in queue control interval (i=15 sec.) clock time cycle no. 1 2 3 4 5 6 7 8 9 10 7:45 am 1 16 39 13 39 2 18 36 12 42 3 20 31 16 40 4 22 42 18 39 5 24 40 22 36 6 28 36 24 33 7 33 33 26 31 8 36 24 31 28 9 42 22 33 24 7:55 am 10 40 16 36 18 total 280 321 234 334 viq=1169 , no of cycle = 10, dvq = (is *viq/vtot ) * 0.9=98 sec. no. of vehicles stopping per lane each cycle =vstop/(n*nc)=3.22 , accel/decel correction factor, cf (ex.a16-2)=-1 number of cycles surveyed, nc =10 , fraction of vehicles stopping, fvs=vstop/vtot.=100% , accel/decel correction delay, dad = fvs * cf=-1 control delay/vehicle, d = dvq + dad = 97sec table (3) r2 comparison of actual and theoretical control delay prediction. paired differences model mean std. deviation std. error mean t sig. (2-tailed) hcs (hcm model) -154.86364 159.18312 33.93796 -4.563 .000 sidra intersection 4/ hcm model -102.91667 176.36225 35.99979 -2.859 .009 sidra intersection 4/ sidra model -441.20833 763.00704 155.74816 -2.833 .009 model r2 std. error of the estimate hcs (hcm model) 0.676 38.80111 sidra intersection 4/ hcm model 0.766 33.55110 sidra intersection 4/ sidra model 0.634 48.47451 table (4) paired t-test comparison of actual and theoretical control delay prediction. 627 table( 5) calibration of the theoretical models using regression analysis hcs (hcm model) sidra intersection 4/ hcm model sidra intersection 4/ sidra model saturation flow (pcphpl) all values of v/c v/c<1 v/c>1 all values of v/c v/c<1 v/c>1 all values of v/c v/c<1 v/c>1 default value* 0.640 0.9158 0.5093 0.7658 0.3842 0.7305 0.6344 0.0134 0.5708 2000 0.6653 0.8156 0.4873 0.7609 0.372 0.7216 0.6367 0.0006 0.5888 2100 0.6609 0.8979 0.4733 0.759 0.5255 0.6976 0.4827 0.1813 0.5756 2200 0.6577 0.8718 0.483 0.6575 0.5567 0.7338 0.6204 0.1549 0.5701 2300 0.6283 0.8276 0.4665 0.6589 0.367 0.6941 0.6908 0.3248 0.6308 * 1900 pcphpln in hcm model and 1950 pcphpln in sidra model table (6) statistical analysis results of the predicted delay time model multiple regression analysis results dependent variable: field delay time standard t parameter estimate error statistic p-value ---------------------------------------------------------------------------- constant 1.43161 126.672 0.0113017 0.9912 d1 0.75301 1.56618 0.480796 0.6401 d2/900 241.446 35.586 6.78487 0.0000 ---------------------------------------------------------------------------- analysis of variance ---------------------------------------------------------------------------- source sum of squares df mean square f-ratio p-value ---------------------------------------------------------------------------- model 56261.4 2 28130.7 35.62 0.0000 residual 8687.52 11 789.775 ---------------------------------------------------------------------------- total (corr.) 64948.9 13 r-squared = 86.6241 percent r-squared (adjusted for d.f.) = 84.1921 percent standard error of est. = 28.1029 mean absolute error = 18.6672 durbin-watson statistic = 1.50625 628 figure (1) the worksheet of delay time field measurement at signalized intersection source (trb 2000) . palestine street palestine intersection 2 palestine intersection 1 figure (2) the satellite image of alfunoon college intersection figure (3) the satellite imag of palestine street intersections. 629 figure (4) average control delay per approach\palestine street intersection 1 (at peak hour) figure (5) average control delay per approach\palestine street intersection 1 (at off peak hour) figure (6) average control delay per approach\palestine street intersection 2 (at peak hour) figure (7) average control delay per approach\palestine street intersection 2 (at off peak hour) figure (8) average control delay per approach\art college intersection (at peak hour) figure (9) average control delay per approach\art college intersection (at off peak hour) figure (10) saturation degree (v/c) per approach\palestine street intersection 1 (at peak hour) figure (11) saturation degree (v/c) per approach\palestine street intersection 1 (at off peak hour) figure (12) saturation degree (v/c) per approach\palestine street intersection 2 (at peak hour) 630 figure (13) saturation degree (v/c) per approach\palestine street intersection 2 (at off peak hour) figure (14) saturation degree (v/c) per approach\art college intersection (at peak hour) figure (15) saturation degree (v/c) per approach\art college intersection (at off peak hour) figure (17) the differences between field delay and theoretical delay computed by the three models according to degree of saturation (v/c) figure (16) theoretical delay calculated by the three models according to degree of saturation (v/c) figure (19) observed field delay versus. theoretical delay (sidra intersection 4/hcs model) figure (18) observed field delay versus theoretical delay (hcs model) 631 appendix a: sample of hcs2000: signalized intersections calculation results analyst: abeer khudhir inter.:palestine intersection (1) intersectin agency: area type: cbd or similar date: 7/28/2010 jurisd _________________________signalized intersection summary_______________________ | eastbound | westbound | northbound | southbound | | l t r | l t r | l t r | l t r | |_______________|_______________|_______________|_______________| no. lanes | 0 5 0 | 0 5 0 | 0 5 0 | 0 5 0 | lgconfig | ltr | ltr | ltr | ltr | volume |723 4507 873 |589 2302 389 |505 862 798 |359 1001 445 | lane width | 13.0 | 13.0 | 11.0 | 11.0 | rtor vol | 0 | 0 | 0 | 0 | _______________________________________________________________________________ duration 0.25 area type: cbd or similar ______________________________signal operations________________________________ phase combination 1 2 3 4 | 5 6 7 8 eb left p | nb left p thru p | thru p right p | right p peds | peds wb left p | sb left p thru p | thru p right p | right p peds | peds nb right | eb right sb right | wb right green 50.0 50.0 50.0 50.0 yellow 4.0 4.0 4.0 4.0 all red 2.0 2.0 2.0 2.0 cycle length: 224.0 secs ____________________intersection performance summary___________________________ appr/ lane adj sat ratios lane group approach lane group flow rate __________ __________ ___________ grp capacity (s) v/c g/c delay los delay los _______________________________________________________________________________ eastbound ltr 1746 7820 3.73 0.22 f f westbound ltr 1747 7828 2.04 0.22 556.0 f 556.0 f figure (20) observed field delay versus. theoretical delay (sidra intersection 4/sidra model) 632 northbound ltr 1568 7024 1.52 0.22 324.8 f 324.8 f southbound ltr 1603 7180 1.25 0.22 204.1 f 204.1 f intersection delay = 812.1 (sec/veh) intersection los = f _______________________________________________________________________________ appendix b: sample of sidraintersection4: signalized intersections calculation results movement summary site: palestine intersection 1 new site signals actuated cycle time = 216 seconds movement performance vehicles 95% back of queue mov id turn demand flow hv deg. satn average delay level of service vehicles distance prop. queued effective stop rate average speed veh/h % v/c sec veh ft per veh mph south: roadname 3l l 561 0.0 1.389 290.4 los f 94.4 2360.5 1.00 1.24 4.3 8t t 947 0.0 0.743 92.3 los f 118.2 2955.1 0.97 0.83 10.5 8r r 887 0.0 1.304 184.8 los f 118.2 2955.1 1.00 1.16 6.2 approach 2395 0.0 1.389 173.0 los f 118.2 2955.1 0.99 1.05 6.6 east: roadname 1l l 640 0.0 1.594 378.3 los f 127.6 3191.1 1.00 1.36 3.4 6t t 2502 0.0 1.594 364.9 los f 133.7 3342.5 1.00 1.54 3.4 6r r 418 0.0 1.594 336.5 los f 103.2 2580.3 1.00 1.29 3.7 approach 3561 0.0 1.594 363.9 los f 133.7 3342.5 1.00 1.48 3.4 north: roadname 7l l 433 0.0 1.071 165.6 los f 58.6 1464.0 1.00 1.04 6.9 4t t 1100 0.0 0.799 96.9 los f 58.6 1464.0 0.96 0.85 10.1 4r r 468 0.0 0.799 101.6 los f 39.7 992.3 0.66 1.01 10.0 approach 2001 0.0 1.071 112.8 los f 58.6 1464.0 0.90 0.93 9.2 west: roadname 5l l 861 0.0 3.001 1007.0 los f 318.9 7973.3 1.00 1.82 1.3 2t t 4744 0.0 3.001 996.4 los f 329.7 8242.8 1.00 2.03 1.3 2r r 909 0.0 2.998 954.8 los f 212.2 5305.0 1.00 1.58 1.4 approach 6514 0.0 3.001 992.0 los f 329.7 8242.8 1.00 1.94 1.3 all vehicles 14471 0.0 3.001 580.3 los f 329.7 8242.8 0.98 1.54 2.2 level of service (aver. int. delay): los f. based on average delay for all vehicle movements. los method: delay (hcm). level of service (worst movement): los f. los method for individual vehicle movements: delay (hcm). approach los values are based on average delay for all vehicle movements. unlicensed trial version movement summary site: palestine intersection 1 new site signals actuated cycle time = 224 seconds movement performance vehicles 95% back of queue mov id turn demand flow hv deg. satn average delay level of service vehicles distance prop. queued effective stop rate average speed veh/h % v/c sec veh m per veh km/h south: roadname 1 l 555 0.0 1.335 424.4 los f 122.6 858.2 1.00 1.48 4.8 2 t 947 0.0 0.723 89.1 los f 295.8 2070.6 0.96 0.83 16.9 3 r 887 0.0 2.133 1144.5 los f 295.8 2070.6 1.00 1.81 1.8 approach 2389 0.0 2.133 557.9 los f 295.8 2070.6 0.99 1.35 3.7 east: roadname 633 4 l 640 0.0 1.606 667.6 los f 188.3 1317.9 1.00 1.80 3.2 5 t 2502 0.0 1.606 657.5 los f 195.9 1371.2 1.00 2.11 3.1 6 r 418 0.0 1.606 665.8 los f 190.3 1332.1 1.00 1.81 3.1 approach 3561 0.0 1.606 660.3 los f 195.9 1371.2 1.00 2.02 3.1 north: roadname 7 l 378 0.0 0.909 115.2 los f 42.2 295.6 1.00 0.95 14.6 8 t 1100 0.0 0.840 92.7 los f 112.9 790.3 1.00 0.87 16.5 9 r 536 0.0 1.290 381.0 los f 112.9 790.3 1.00 1.30 5.2 approach 2014 0.0 1.290 172.3 los f 112.9 790.3 1.00 1.00 10.3 west: roadname 10 l 861 0.0 3.020 1950.1 los f 498.2 3487.3 1.00 2.62 1.1 11 t 4744 0.0 3.019 1940.9 los f 514.2 3599.2 1.00 3.01 1.1 12 r 909 0.0 3.020 1949.3 los f 496.7 3476.6 1.00 2.37 1.1 approach 6514 0.0 3.019 1943.3 los f 514.2 3599.2 1.00 2.87 1.1 all vehicles 14478 0.0 3.020 1153.1 los f 514.2 3599.2 1.00 2.15 1.8 level of service (aver. int. delay): los f. based on average delay for all vehicle movements. los method: delay (rta nsw). level of service (worst movement): los f. los method for individual vehicle movements: delay (rta nsw). approach los values are based on average delay for all vehicle movements. 5-2-2011.pdf 51 in this study, the stress analsis of the steel-aluminum compound thick cylinders under the effects of internal pressure, thermal loading and rotational loading has been carried out using the finite element method. the structure is treated as axisymmetric body, because each of the geometry and applied loads are symmetric about the longitudinal axis. the stresses variations (hoop, axial, radial, equivalent) through the walls thickness are determine here and the results were checked using two theories of elastic failures (tresca and von-misses). the results showed that, the hoop stresses at the inner surface is about (600 mpa) due to effect of internal pressure, (-500 mpa) due to thermal load, (57 mpa) due to effect of rotational speed while about (150 mpa) due to the effect of the total loading. it can be seen that the max. hoop stress concentrated at the contact surface between the two cylinders. also the temperature distribution through the cylinder thickness has been determined. key word: thick cylinder, compound, temperature distribution, thermal stress . . ) / ( ، . . )equivalent, radial and hoop ( )tresca, von-misses.( )hoop stresses ()600 mpa ( )-500 mpa ()57 mpa ()157 mpa ( . . . 52 the compound mould of the centrifugal casting technique, represent the most common of the applications of the compound thick cylinder which subject to internal pressure, rotational speed and thermal loading. therefore, an accurate and reliable technique is essential in order to obtain the stresses. the thermal load and rotational speed are one of the most important parameters that effects on the behavior of the stress through the thickness of the compound thick cylinder and this behavior depends on the mechanical and thermal properties which, in fact, vary with the temperature variation [1]. the effect of temperature on the deformation field is not one-way phenomena. when the mechanical and thermal aspects are coupled, and inseparable. in general, thermal stress generation can be attributed to two main causes [2, 3]. when the temperature distribution in the body is uniform two particular causes that produces stresses: existence of external constraints, as occurs, if when the ends of a beam are fastened within a wall. and non homogeneity of the body such as discontinuity of surfaces. when the temperature distribution in the body is not uniform which gives a non-uniform deformation, and a system of stresses within the body is developed when the body undergoes a thermal transient state. presented an analytical solution for the calculation of the axisymmetric thermal and mechanical stresses in thick hollow cylinder made of fgm by using navier equation [4]. shows the stress variation along the radial direction of rotating fgm cylinder subjected to internal pressure [5]. investigated the residual stresses induced by autofrettage process in layered and functionally graded composite vessels. this study showed that the induced residual stress at the inner surface of composite vessels much higher values compared to a metal vessel counter part depending on the properties of composite constituents [6]. studied the transient thermal stresses in a transversely isotropic, semi-infinite solid circular cylinder subjected to a convection heat loss on the end surface. the theoretical analysis considered the effect of the thermal and elastic isotropic of the material properties on thermal stresses in a transversely isotropic semi-infinite circular cylinder due to cylindrical surface heat generation [7]. it is very important to study the temperature distribution and stress analysis of the compound thick cylinder subjected to different loading simultaneously such as internal pressure, rotational speed and thermal loading to know the behavior of stress between the single cylinder and compound cylinder. thick cylinder subjected to internal pressure only [8] from the follow equilibrium equation for thick cylinder (1) the lame’s equation can be derived 22 , 53 122 2 (2) 122 2 (3) 2 (4) thick cylinder subjected to internal pressure and rotational speed [8 & 9] 8 .. 3 22 2 (5) 8 .. 31 22 2 (6) while due to thermal loading [8 & 9] also the temperature rise of the thick cylinder will lead to induce thermal stresses. .... 1 1 . 22 22 2 (7) 2 22 22 2 ..... 1 1 . (8) .. (9) when the model structural components are rotationally symmetric about an axis such as the pressure vessels and solid rings, and if these structures are also subjected to axisymmetric loads, a two-dimensional analysis of a unit radian of the structure yields the complete stress and strain distribution as illustrated in [10]. at first the shape functions were developed on a master element which is defined in ξ, η coordinates for normal coordinates [11]. the lagrange shape function ni, where i=1, 2, …….8 are defined such that ni is equal to unity at node i and is zero at other nodes. inparticular, consider the definition of ni: n1= 1 at node 1 = 0 at node 2, 3, ………8 this element belongs to the serendipity family of elements. the element consists of eight nodes all of which are located on the boundary. indefining ni which refer to the master element shown in . the general equation for shape functions at all corner nodes is 54 1.1.1 4 1 for midside nodes with ξi = 0 1.1 2 1 2 for midside nodes with ηi = 0 21.1 2 1 the displacement approach to the solution of finite-element problems, a method more widely used than the stress is illustrated by an axially loaded spring; . (10) where: is the element stiffness matrix is the element displacement vector is the element applied load vector ... (11) ...2 .. ... .].[det. ......2 16444 1 1 1 1 4161616 (12) 164 strain-displacement relationship matrix is given by: 0...00 ........ 0....00 0....00 821 8811 821 821 164 55 [d] is the elasticity matrix which is in axisymmetric is given by: 10 0 2 )21( 00 01 01 . )21)(1(44 8 3 3 2 2 1 1 . . . and the load vector is given by: (13) where : -is the load vector due to distribution pressure [12] -centrifugal load under (inertia) force per unit volume. thermal load vector. the load vector due to distribution pressures is given by: ... 1 1 (14) where 821 21 ....00 0....00 56 but the centrifugal load vector (inertial) force per unit volume depends on assumption that the center of rotation coincides with origin of the x, y axes. therefore the radially outward body force pr on an element area da is given by: .. 2 (15) where: -is the angular velocity in rad/s ρ-is the mass per unit volume of the material r-is the radial distance from the origin to the centroid of the element area prcan be resolved into components parallel to x and y axes such that ..2 where the x and y correspond to the coordinates of the centroid of the element area .det.... ..... 1 1 1 1 2 2 while the thermal load vector is given by [13] . .. where -thermal stress vector -thermal strain vector ,,, ,,, .,0,.,. δt-uniform increase in temperature. ..det..2 1 1 1 1 (16) 57 for the finite element method analysis of the compound thick cylinder problem, the ansys 11 package program is adopted. this program has very efficient capabilities to perform finite element analysis of most engineering problems. where the material properties, dimension and loads, differ from the inside and outside cylinder. due to symmetry only this problem treated as axisymmetric problem. a single type of element is used throughout this study namely the parabolic isoperimetric element, a typical two-dimensional version of which is illustrated in fig. (2). parabolic isotropic elements are extremely versatile, good performers and are well tried and tested. practical experience suggests that, for a given number of total degrees of freedom in a structure, greater accuracy is achieved by used of fewer complex elements in placed of a larger number of simple elements. the compound thick cylinder as previously stated is plane-strain problem or axisymmetric problem, and the first step of finite element analysis is to discretize the structure into finite elements connected at nodes. for a structure as a compound tubes, it is necessary to discretize it into a sufficient number of elements in order to obtain a reasonable accuracy. the mesh generation of the compound thick cylinder as shown in . where the thickness divided into twenty of 8-node quadrilatic (parabola) isoparametric element with total of 85 nodes. the problem is solved using the finite element method as axisymmetric problem with longitudinal axis for compound thick cylinder. the finite element solution was based on the following case study. two type of material used here in the analysis (steel, aluminum). the compound thick cylinder shown in used for the modeling analysis consists of two circular cylinder with varying properties and have the following specification. inner radius = 50 mm inner radius = 80 mm outer radius = 80 mm outer radius = 100 mm the two cylinder are fitted without any force (the steel cylinder fits slightly into the aluminum one at room temperature) [14] e = 207 gpa e = 73 gpa = 0.3 = 0.33 α = 11.7*10-6 1/oc α = 23*10-6 1/oc k = 35 w/m.oc k = 121 w/m.oc ρ = 7850 kg/m3 ρ = 3000 kg/m3 58 pi = 300 mpa. ti = 250 oc to = 25 oc ω = 1000 rad/sec. shows the relationship between temperature and the cylinders thickness. it is clear from this figure that the temperature is decrease with increase the radius in nonlinear relationship and in different manner for steel and aluminum that depend on thermal conductivity. show the relationship between stresses variation (radial, hoop, longitudinal and equivalent due to von-misses and tresca) and the cylinder thickness due to the thermal load. it is clear from that hoop stress and longitudinal stress increase with increase cylinder thickness and the rate of increase differ from steel to aluminum material depend on thermal conductivity. it can be seen from this figure that the behavior of radial stress in steel thickness differs in aluminum thickness. while from for equivalent stress, behavior according to tresca is higher than vonmisses and have nonlinear relationship with cylinder thickness. show the relationship between stresses variation and the cylinder thickness due to effect of the rotational speed. it can be seen from that the hoop stress and longitudinal stress decrease with increase the cylinder thickness in different manner for the two metals used. while the radial stress increase and then decrease to zero value. while from the equivalent stress decrease with the increase the cylinder thickness and the value of tresca is higher than von-misses. show the relationship between stresses variation and the cylinder thickness due to internal pressure only. it is clear from this figure that the hoop stress decrease with increase the cylinder thickness while the longitudinal stress approximately constant and the radial stress decrease to zero value at outer diameter. while from the equivalent stress decrease with increase the cylinder thickness and the equivalent stress due to von-misses lower than tresca. illustrate the stress variation through the cylinder thickness due to total load. it can be seen from this figure the stresses increase with increase the cylinder thickness in nonlinear relationship for steel and aluminum material that depend on the material properties. show the relationship between equivalent stress variation and the cylinder thickness due to total load. it can be seen that the tresca behavior is higher than von-misses and have nonlinear relationship. 1. temperature decreases with the increase of the radius of thick cylinder, and the behavior of temperature in steel wall differ in that in aluminum wall. 2. stress gradient in steel wall are higher than in aluminum wall. 3. hoop and longitudinal stress increase with radius of thick cylinder due to effect of thermal loading while decreases with the radius due to effect of internal pressure and rotational speed. 4. behavior of radial stresses through the wall thickness due to effect of thermal load is verses that due to effect of rotational speed. 5. equivalent stresses (von-misses and tresca ) due to thermal load have behavior differ than the equivalent stresses due to rotational speed and internal pressure. 59 6. hoop stress at inner surface due to effect of type of loading as follow: type of loading hoop stress thermal load -500 mpa rotational speed 57 mpa internal pressure 600 mpa total load 157 mpa 7. max. hoop stresses concentrates at the intermediate radius of the compound thick cylinder. [1] deter, g. e., “mechanical metallurgy”, mcgraw hill book company, london, (1988). [2] nowinski, j. l., “theory of thermoelasticity with applications”, sijthoff and noordhoff int. pub., (1978). [3] boley, b. a. and weiner, j. h., “theory of thermal stresses”, john wiley and sons inc. [4] m. jabbari, s. sohrabpour, m. r. eslami, “mechanical and thermal stresses in a functionally graded hollow cylinder due to radially symmetric loads”, international journal of pressure vessels and piping, elsevier, (2002). [5] gholam hosein rahimi and mohammad zamani nejad, "elastic analysis of fgm rotating cylindrical pressure vessels", journal of the chinese institute of engineers, vol. 33, no. 4, (2010). [6] b. h. jahromi, a. ajdari, h. nayeb-hashemi and a. vaziri, "autofrettage of layered and functionally graded metal-ceramic composite vessels", journal of composite structures, elsevier, (2010). [7] noda, n. and ashida, f., “three dimensional transient thermal stresses of reactor graphite subjected to internal heat generation and asymmetric surface heating”, nuc. eng. des., vol.100, (1987). [8] hearn, e. t., “mechanics of materials” vol. (2), pregamon press ltd, (1977). [9] anthony c. fischer-cripps, "introduction to contact mechanics", springer, new york, second edition, (2007). [10] klans, j. bathe, ‘finite element procedures”, prentice-hall international, inc., (1996). [11] tirupathi, r. c. and ashok, d. b. “introduction to finite elements in engineering”, second edition. printice, hall of india, (1997). [12] y. k., cheuny and mf yeo, “a practical introduction to finite element analysis”, piiman publishing limited, (1979). [13] e. hinton and d.r.j., owen, “finite element programming”, academic press, (1997). 60 [14] william d. callister, j., “material science and engineering an introduction “, john whiley and sons, inc., (2007). thick cylinder with symmetric structure and loading 61 : 8-node quadrilateral isoperimetric element (a) in x,y space and (b) in ζ, η space 62 mesh generation of compound thick cylinder compound thick cylinder cross-section ro=0.1 m rm=0.8 m ri=0.05 m 63 : temperature distribution through the cylinder thickness º 64 : equivalent stress variation through the cylinder thickness due to thermal load : stress variation thought the cylinder thickness due to thermal load 65 : equivalent stress variation through the cylinder thickness due to rotational load : stress variation thought the cylinder thickness due to rotational load 66 : equivalent stress variation through the cylinder thickness due to internal pressure : stress variation thought the cylinder thickness due to internal pressure 67 : equivalent stress variation through the cylinder thickness due to total load : stress variation thought the cylinder thickness due to total load 9-4-2010.pdf speed control of d al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 speed control of d.c series motor by using power mosfet chopper ass. lec. abdullah omran ali electrical department al-musayab technical iinstitute abstract the aim of this paper is to construct a system which can control the speed of d.c series motor by using power mosfet chopper .the system contains close loop control which has a performance and characteristics in the operation.the close loop control system contains digital pulse width modulation circuit, driving circuit, over speed, and over current protection circuit. the power mosfet devices are now available in production quantities and are already being utilized from switched power applications including motor control.hexfet power mosfet type irfk4h350 is selected for this application due to its relative high current -handling ability up to 50a and a maximum drain -tosource voltage of 400v. all the theoretical transient responses of speed and current reveal fairly close agreement with practical response, the maximum deviation between them is (5%) . key words: mosfet, chopper, motor, drain, source, thyristor, transistor. السیطرة على سرعة محرك تیار مستمر باستخدام المقطعات عمران عليهللاعبد. م.م المسیب/المعهد التقني/قسم الكهرباء :الخالصة الهــدف مــن هــذا البحــث هــو الســیطرة علــى ســرعة محــرك تیــار مســتمر تــوالي باســتخدام مقطــع ترانزســتور تــأثیر المجــال م السـیطرة المغلقـة یحـوي دائـرة التحمیـل العرضـي النظام یعتمد السیطرة المغلقة والذي یحوي شكل وخـواص العمـل ، نظـا.المعدني سـتور تـأثیر المجـال ستران. وجهاز قیاس السرعة الفائقة والتیار العالي ودائرة قیاس التیار وحمایة من السرعةللنبضة ودائرة السوق hexfet power(ترانزسـتور تـأثیر المجــال نـوعالمعـدني یسـتعمل فـي المحركـات كمفـاتیح سـیطرة وفـي بحثنـا هـذا اسـتخدام mosfet type irfk4h350 (50لتحمل تیار عاليوذلك للقابلیة العالیةa)( وفولتیة بین المصدر والساحب)400v(. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٢ nomenclature symbol notations units id,if = instantaneous armature current during conduction freewheeling intervals. a. j = polar moment of inertia of motor pulse load . kg.m2 k = motor voltage constants. v/rad/sec. l = total inductance of armature circuit . h r = total resistance of armature circuit . ω. t = periodic time of chopper. s. v = source voltage. v. w = instantaneous speed. rad/sec . greek symbols β = the sum of βv and kg , n.m/rad/sec ω = symbol of ohm (value of resistance) introduction. the d.c series motor operates with decidedly drooping speed as load is added, the no-load speed usually being high, the torque is proportional to almost the square of the current at low saturation and to some power between one and two as saturation increases.by virtue of its ability to handle heavy torque overloads while reducing the associated power overload with speed drop, and by virtue of its ability to withstand severe starting duties, the series motor is best adopted to hoist, crane and traction -type load [uman,1983]. from the basic equation for the speed of rotation (1) the rotating speed can be varied by varying either the applied voltage, va , or the armature current ia[rashid,1988] speed above the base speed (the speed when normal armature voltage and full armature current are applied) are obtained by armature current control ( constant horsepower drive ) .speeds below base speed are obtained by armature voltage control ( constant torque drive ) [uman,1983 ]. classically the variation of the applied voltage is obtained from a fixed d.c voltage by two methods. in the first method variable resistance inserted between the fixedvoltage d.c source and the motor. this method is inefficient because of looses in the resistance.in the second method the motor -generator set is used to supply the power to the motor whose speed is to be controlled [sen,1981]. a variable d.c output voltage of generator is obtained by controlling the field current of d.c generator which is driven by a constant speed d.c motor. this system is still used in some industrial drives, therefore the system is bulky, costly, slow in response and less efficient. in 1960 high power thyristor devise became available to make the solid state d.c power converter practical. these converters offer greater efficiency, fast response, smooth operation, smaller size and lower weight and cost. the chopper circuit of force commutated thyristors is used to control the speed of d.c series motor. the extensive work has been done on mathematical analysis of the performance of the d.c series motor that is controlled by this circuit .the following survey for literature shows the methods which are used for analysis. franklin[franklin,1972] found the theoretical relation between currents, fluxes and pulse duration in d.c series motor energized by power pulses obtained by using d.c thyristor. mellit & rashid[mellite,1974] presented a computer al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٣ based method for analyzing the performance of d.c chopper circuit. damle & dubey[damle,1976] described the interdependence of armature induced voltage and armature" current and the 'fact that the radiation between them is nonlinear. ahron & applebaum[ahron, 1981] analyzed the transient response of d.c series motor. dubey & shepherd[damle,1976] analyzed the transient response of d.c series motor controlled by chopper with time -ratio control (trc) or current limit control (clc) with square output voltage. the object of the present work can be summarized as follows :1) construct one quadrant chopper using power mosfet , this chopper is used to drive a d.c series motor . 2) construct over current and over speed protection circuit . 3) analyze the performance of d.c series motor driven by power mosfet chopper[thomas,2001]. the analysis is simplified by taking the average values of voltage, current, speed and torque instead of the instantaneous values and this gives good approximation when the chopping frequency is high, also the nonlinearly of the magnetization curve is taken into account . mosft transistor that can be fabricated in single integrated circuit also it can modeled very simple as switch[ken,2000]. 4) simulate the analysis in the microcomputer and drawing the transient response of speed and current for step change in the mean values of applied voltage and the load to compare with the experimental transient response. control strategies. there are two types of control strategies employed in d.c chopper [ uman,1983] namely: 1) time ratio control (trc) 2) current limit control (clc) in the time ratio control the value of ton/t is varied. this is effected in two ways. they are variable frequency operation and constant frequency operation. in form either t on or t off is kept constant and the other one is varied, effectively changing chopper period and resulting in variable frequency operation. in this paper the values of ton or t off are varied such that t is constant resulting in a constant frequency operation . in current limit control the chopper is switched on and off so that the current in the load is maintained between two limits. when the current exceeds upper limit the chopper is switched off. during off period the load current freewheels and decreases exponentially. when it reaches the lower limit the chopper is switched on . current limit control is possible either with constant frequency or with constant ton .the current limit control is used only when the load has energy storage elements. the reference values are the load current or load voltage. these control strategies are the load current or load voltage. these control strategies are illustrated in fig.(1). in this work the time ratio control with constant frequency (this type also called pulse width modulation) control is used. theory of operation. the chopper is now widely used for the control of d.c series motor[lander,1987]. the output voltage of the chopper is controlled by using pwm control. a chopper with square-wave output voltage normally operates in two modes; namely, the duty interval and the freewheeling interval, during chopping cycle. the performance of d.c series motor is described by the following differential equations[lander,1987], referring to fig.(2). duty interval . (2) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٤ also from dynamic of motor pulse load free wheeling interval in equations (2-5) , the terminology k(id) and k(if) denotes that k is a function of the instantaneous values of the motor current, so that the equation represent a set of simultaneous, nonlinear differential equation . for calculation of the transient response of current and speed the above equations are solved numerically for each interval of the chopping cycle by using the final conditions of the pervious interval as the initial condition for each successive chopping interval. this method has the advantages that it permits the calculation of transient response exactly for the assumed model. the necessary computation time is, however quite large, particularly for system with slow transient response. system implementation. fig.(3) shows the block diagram of the implemented closed loop chopper –fed d.c series motor. the speed of the d.c series motor change with the load torque. to maintain a constant speed, the armature (and/or) field voltage should be varied continuously by varying the duty cycle of d.c. chopper. a closed loop control system has the advantages of improved accuracy; fast dynamic response and reduce effect of load disturbance and system nonlinearities. the block diagram of the closedloop chopper-fed d.c. series is shown in fig.(3). if the speed of the motor decreases due to the application of additional load torque, the speed error increases. the speed controller signal u , changes the duty cycle of the chopper, and increases the armature voltage of the motor. an increased armature voltage develops more torque to restore the motor speed to the original value, the drive normally passes through transient period until the developed torque is equal to the load torque [rashid,1988]. power mosfet driving circuit fig.(4) shows the total power needed to drive power mosfet is very small, all that must be provided is the capability to charge and discharge the gate to-source capacities (typically 8.0 nf) in short time. this ensures that the switching losses are minimized. the output of the protection circuit is coupled to power mosfet gate drive stage via opto -coupler ,the output side opto coupler is powered from an isolated power supply ( +5v). digital pwm circuit. it consists of a binary switch which contains eight micro switches ,one side of each is connected to 5v through a resistance of 1 k ω value and then applied to latch ic1 type (74hct273e),. the other side is connected to the common point of the power supply. current measurement circuit. a d.c current transfoffi1er of type rdct50/b is used .armature current flow in the direction of arrow produces a positive voltage across the load with respect to the common line .the d.c current transformer is a constant current device. it is only used with the load connected. (3) (4) (5) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٥ speed measurement circuit. optical tachometer is used to measure the speed of the machine. the speed encoder produces a train of pulses whose frequency is linearly depended upon the motor speed. overcurrent and over speed protection circuit. d.c motor has low resistance and at starting the back e.m.f is zero, therefore, high current passes through the chopper and the motor .also if the load of d.c series motor is not coupled the speed becomes very high therefore protection from over current and over speed is necessary. the current signal and speed signal are compared with reference values for current and speed respectively. two comparators inside one chip (ici type lm139) are used one for current and another for speed. control system using microprocessor. the advantages of microprocessor controllers for a variable speed drives are reducing the size and cost of the hardware electronics, and having more precision and stability. fig.(5) shows the flowchart of the software. results and conclusion. the purpose of the present. work is to construct d.c power mosfet chopper driving for driving d.c series motor. the power mosfet devices are now available in production quantities and are already being utilized for switched power applications including motor control.the use of power mosfet eliminate the need for a commutation circuit that is used with the thyristor choppers to turn the thyristor off and allows the chopping frequency to be raised, the switching and snubber losses associated with power mosfet sets an upper bound on the chopping frequency from an efficiency point of view . the chopping frequency is chosen to be equal to (3.92 khz) , the inductance of the motor (48 mh) is sufficient to smooth the armature current , no need to add external inductance.the maximum peak – to peak ripple in armature current is 3% . the supply d.c voltage =180 v .the experimental results for maximum peak -to-peak ripple is equal to 150ma . for duty cycle 0.75.the experimental value of peak -to -peak ripple is equal to 100ma. the parameters of speed controller that gives good response with no over shoot are kp=0.5 and ki=0.1 the closed loop system is tested for step change in load resistance from 100 to 50 as shown in fig. (6). fig.(7) shown the experimental response is compared with the theoretical response of the speed for step change in load resistance rl from 50 to 100 . reference speed is changed from 46 rad/sec to 59.3 rad/sec, the system is tested for this step change , the steady state operating point (wavo=46rad/sec and iavo=3.05a).comparison between experimental and theoretical response is in fig.(8). fig.(9) shows the experimental and theoretical transient response of the speed for step change in reference speed from 68 rad/sec to 44.7 rad/sec. the following points are deduced tram the tests: 1) high gain and transcoductance which are variant with increasing current : mosfet are voltage -driven devices requiring simple drive circuits with low energy sources such as mos logic or opto devices. 2) raggedness, with no secondary breakdown turnoff. 3) a positive temperature coefficient, and hence ease of parallel connection. 4) an integral reverse body – drain diode with a similar current – handling ability to that of transistor itself . al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٦ references. ahron tablon and joseph applebaum, " transient analysis of a d.c series motor .1981. damle p. d. and dubey g. k . , "analysis of chopper. fed d.c series motor" ieee trans. ind .electron center in strum .١٩٧٦ franklin p.w.," theory of d.c motor controlled by power pulses part i. motor operation, iggetrans ".power app. syst .vol.pas.-91 , jan/feb.1972 ken marten," digital integrated circuit design". oxford university press. inc.,2000. lander c.w.,"power electronics ", mcgraw hill , 1987 mellitt b. and m.h .rashid , "analysis of d.c chopper circuits by computer ". 1974 rashid m.h, " power electronics: circuit, devices, and applications" u.s.a: prentice -hall inc, 1988. sen p.c . , "thyristor d.c drives" , john wiley 1981. thomas l. floyd, "electronic devices", prentice hall international,inc,1996,1999,2001. umans ,fitzgerald and kingsley " electrical machinery" singapore :mcgraw hill ,inc ,1983. williams b .w, "complete state -space digital computer simulation of chopper -fed d.c motor .1978. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٧ fig.(1) control strategies of a chopper. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٨ fig.(2) representation of a chopper – controlled dc series motor. (a) basic schematic diagram . (b) equivalent circuit of duty interval . (c) equivalent circuit of freewheeling interval . al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٩ fig.(3) block diagram of a closed – loop fed dc series motor . fig.(4) driving circuit for dc chopper. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٢٠ fig.(5) the software flowchart of speed control. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٢١ fig.(6) experimental and theoretical closed loop transient response of the speed for step change in load resistance rl from 100 to 50 , wavo = 66.6 rad/sec., iavo = 2.7a . al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٢٢ fig.(7) experimental and theoretical closed loop transient response of the speed for step change in load resistance rl from 50 to 100 , wavo = 55.2 rad/sec. , iav0= 3.38a . al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٢٣ fig.(8) experimental and theoretical closed loop transient response of the speed for step change in reference speed wr from 46.0 rad/sec to 59.3 rad/sec , wavo = 46.0 rad/sec , ivao = 3.05a . al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٢٤ fig.(9) experimental and theoretical closed loop transient response of the speed for step change in reference speed wr from 68.0 rad/sec to 44.7 rad/sec, wavo=68.0 rad/sec , iavo=3.16a. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 44 mechanical properties of araldite matrix composites reinforced with hybrid carbon kevlar fibers ali i. al-mosawi technical institute-babylon mechanical department dr. abbas a. al-jeebory al-qadissiya university college of engineering abstract the mechanical properties of araldite matrix composites incorporated with hybrid carbon kevlar fibers were evaluated . there are indications that the incorporation of both fibers into a single matrix which is araldite resin will stabilize mechanical properties and lowering manufacturing costs . in this research the impact strength , tensile strength ,flexural strength ,and hardness were studied for composite material reinforced with hybrid fibers as a woven roving )°90-°0( with density (225g/cm3) and (285g/cm3) for carbon and kevlar fibers respectively . these fibers were mixed with araldite resin in different reinforcement percentage (20%,40%,60%) and the effect on the above mechanical properties were studied , where we see improves in these mechanical properties after reinforcement by fibers the value of mechanical properties will increase with increasing percentage of reinforcement . keywords : hybrid fibers , composite material , mechanical properties . رلدایت مقواة بألیاف الكاربون وألیاف كیفالر المیكانیكیة لمادة مركبة ذات أساس من اإلالخواص الھجینة عباس علیوي الجبوري.د جامعة القادسیة كلیة الھندسة علي إبراھیم الموسوي بابل–المعھد التقني قسم المیكانیك .الخالصة ة للمادة المركبة ذات أساس من اإلرلدایت المدمج مع ألیاف الكاربون وألیاف تم في ھذه الدراسة حساب قیم الخواص المیكانیكی الخواص المیكانیكیة حیث ھنالك مؤشرات على إن دمج ھذین النوعین من األلیاف في أرضیة واحدة یحافظ على. كیفالر الھجینة ، مقاومة اإلنثناء ، والصالدة للمادة المركبة في ھذا البحث تم دراسة مقاومة الصدمة ، مقاومة الشد. ویخفض تكالیف التصنیع (285g/cm3) و(225g/cm3)ألیاف الكاربون وألیاف كیفالر بكثافة من)90°-0°(المقواة بألیاف ھجینة بشكل حصیرة ثنائیة راسة أثر ود(%20,%40,%60)حیث تم مزج ھذه األلیاف في أرضیة من راتنج اإلرلدایت وبنسب تقویة مختلفة . على التوالي ذلك على الخواص المیكانیكیة ، حیث تم تحسین ھذه الخواص بعد التقویة باأللیاف إضافة إلى زیادة قیمة ھذه الخواص مع زیادة .نسبة التقویة باأللیاف .مادة المركبة ، الخواص المیكانیكیة األلیاف الھجینة ، : الكلمات الدالة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 45 introduction . a composite is a structural material that consist of two or more constituents that are combined at a macroscopic level and are not soluble in each other . one constituent is called the reinforcing phase and the one in which it is embedded is called the matrix [auter,2006] . the composite material however , generally possesses characteristic properties , such as stiffness ,strength ,weight ,high-temperature performance ,corrosion resistance ,hardness , and conductivity that are not possible with the individual components by themselves . analysis of these properties shows that they depend on (1) the properties of the individual components; (2) the relative amount of components; (3) the size ,shape ,and distribution of the discontinuous components; (4) the degree of bonding between components; and (5) the orientation of the various components [degarmo,2008] . there are many types of composite materials and several methods of classifying them , one such method is bases on geometry and consists of three distinct families : 1laminar composites : laminar composites are those having distinct lagers of materials bonded together in some manner [liyong,2002] . 2particular composites : particular composites consist of discrete particles of one material surrounded by a matrix of another material [degarmo,2008] . 3fiber-reinforced composites :the most popular type of composite material is the fiberreinforced composite geometry ,where continuous or discontinuous thin fibers of one material are embedded in a matrix of another [degarmo,2008] . g.morom ,e.drukkler ,a. weinberg ,and j.banbaji studied the effect of hybrid fibers (carbon / kevlar) on the impact strength of epoxy resin [morom,1986] . also ali investigated the effect of changing the reinforcement percentage by fibers on mechanical properties, for composite material consists of conbextra epoxy (ep-10) resin reinforced by biaxial woven roving kevlar fibers [ali,2009] . azhdar studied the impact fracture toughness of fiber reinforced epoxy resin[azhdar,1992] dr. abbas , ali , and sajed studied effect the change of reinforcement percentage of fibers on the thermal conductivity for polymeric composite material consist of conbextra epoxy (ep-10) resin reinforced by biaxial woven roving s–type glass fibers [dr. abbas, ali,2009] . hybrid composites . hybrid composites involve two or more types of fibers set in a common matrix .the particular combination of fibers is usually selected to balance strength and stiffness , provide dimensional stability ,reduce cost ,reduce weight ,or improve fatigue and fracture resistance . types of hybrid composites include (1)interply(alternating layers of fibers); (2) intarply(mixed strands in the same layer) ;(3) interply-intarply ;(4) selected placement(where the more costly material is used only where needed) ;and (5) interply knitting(where plys of one fiber are stitched together with fibers of another type) [degarmo,2008] . kevlar fibers . kevlar fibers is an organic aramid fiber with (3100 mpa) tensile strength, and (131,000 mpa) elastic modulus. a density approximately one-half of aluminum, good toughness, and negative thermal expansion coefficient .in addition , it is flame retardant and transparent to radio signals al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 46 ,making it attractive for a number of military and aerospace application where the service temperature is not excessive [4]. table(1) shows some characteristic of kevlar fibers . carbon fibers . high strength , high modulus carbon fibers are about (7µm -8µm) in diameter and consist of small crystallites of turbostratic graphite ,one of the allotropic forms of carbon . there are three routes for producing fibers with graphite layers oriented preferentially parallel to the fiber axis: (1) orientation of polymer precursor by stretching ; (2) orientation by spinning ;(3) orientation during graphitization [morom,1986]. araldite resin (epoxy resin group) . araldite resin belong to epoxy group which have excellent thermal and physical properties ,and usually used in composite materials for different application ,where it distinct by excellent adhesive capability especially to fibers ,also it retain constant dimension after dryness [dorey,1978] . experimental work . the experimental work includes the following points : 1materials: there are three types of materials employed in this study: amatrix material, araldite resin (cy223) with density of (1.15-1.2 g/cm3) which belong to epoxies group was used in this study. figure (1) shows the chemical structure of araldite resin. breinforcing fibers: two types of fibers used here : 1carbon fibers: a woven roving fibers )º 90 º 0( with density of (225 g/m3). 2kevlar fibers : a woven roving fibers )º 90 º 0( with density of (285 g/m3). these types of fibers used as consecutive layers in same matrix . figure (2) shows the chemical structure of kevlar fibers. 2preparation test specimens: four types of specimens were manufactured as follows : aimpact specimens : impact specimens fabricated according to the (astm-e23) standard suitable to charby impact instrument .notch depth is (0.5mm) and notch base radius is (0.25mm). btensile strength specimens :these specimens manufactured according to the (iso-r-527) standard . chardness specimens : hardness specimens are a disc shape with (25mm) diameter and (10mm) thickness . dflexural strength specimens :these specimens fabricated according to (astm-d790) standard as a rectangular shape(10mm×135mm) . three specimens were manufactured for each test which different by the resin and reinforcement percentage as shown in table(2) . hand molding was used to manufactured the specimens . some resin spread in the mould and the fiber layer put on it and this process repeated to obtain the desired thickness . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 47 3mechanical tests :in this study four types of mechanical tests were used to determined the properties of composite material ,and these tests are : aimpact test : charby impact instrument was used to determine the impact resistance of composite material . btensile test :this test was used to calculate the tensile strength of composite material under uniaxial load ,where we used the universal test instrument manufactured by z.n corporation (china) to measured this property with a(20kn) load . chardness test : in this test we used “brinell method” was used to measure hardness , this test made with a steel ball (5mm) diameter and (10kg) exposition load, loaded into specimens for (15sec) , and the hardness number represent the diameter of impression after remove the load , which left on surface by the ball. universal test instrument manufactured by z.n corporation (china) used for this test . dflexural strength test : flexural strength can be measured by three point test by using universal hydraulic press (z.n corporation) to calculate the maximum load exposed on middle of the specimen . results and discussion . the mechanical properties of composite materials have a great important in the field of using these materials ,where the values of these properties should be high and acceptable so it can done its duty successfully .from the mechanical tests done on the araldite resin reinforced with hybrid carbon and kevlar fibers we get the results shown in the diagrams which represent the values of impact strength , tensile strength , hardness, and flexural strength with the fiber reinforcement percentage : 1impact strength : figure(3) shows the value of impact strength with fibers reinforcing percentage .generally ,the impact resistance considered low to the resins due to brittleness of these materials ,but after reinforcing it by fibers the impact resistance will be increased because the fibers will carry the maximum part of the impact energy which exposition on the composite material .all this will raise and improved this resistance .the impact resistance will continue to increase with increased of the fibers reinforcing percentage [ali,2009]. 2tensile strength :the resin considered as brittle materials where its tensile strength is very low as shown in figure(4) ,but after reinforcing by fibers this property will be improved greatly ,where the fibers will withstand the maximum part of loads and by consequence will raise the strength of composite material .the tensile strength will be increased as the fibers percentage addition increased , where these fibers will be distributed on large area in the resin [dr. abbas, ali,2009]. 3flexural strength :as mentioned above ,the resin is brittle ,therefore its flexural strength will be low before reinforcement as shown in figure(5) .but after added the fibers to this resin the flexural strength will be raise to the producing material because the high modulus of elasticity of these fibers will helps to carry a large amount of loads and raise this strength [ali,2009]. 4hardness :generally the plastic materials have low hardness ,where we observed in figure(6) the lowest value for araldite resin before reinforcement .but this hardness value will greatly increased al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 48 when the resin reinforced by hybrid fibers ,due to distribution the test load on fibers which decrease the penetration of test ball to the surface of composite material and by consequence raise the hardness of this material .the hardness will be increased with increasing the percentage of fibers reinforcement [azhdar,1992]. conclusions . from the obtained results we get : 1low mechanical properties ( impact, tensile, flexural strength, and hardness) of the araldite resin . 2improvement of mechanical properties after reinforcement by carbon and kevlar fibers . references . 1auter k.kaw “ mechanics of composite materials” ,2nd edition ,taylor and francis group ,llc ,2006 . 2e.p.degarmo, j.t. black, and r.a. kohser “ materials and processes in manufacturing ” , 10th edition , john wiley & sons , 2008 . 3liyong tong ,adrian p.mouritz ,michael k.bannister “3d fiber reinforced polymer composites” ,elsevier science ltd ,first edition ,2002 . 4g.morom ,e.drukkler ,a. weinberg ,and j.banbaji “impact behavior of carbon / kevlar hybrid composites” , composites ,vol 17 ,no 2 ,1986 .pp150-153. 5-ali i.al-mosawi “study of some mechanical properties for polymeric composite material reinforced by fibers ” , al-qadessiyah journal for engineering science , vol 2 , no 1 , 2009 . pp.14 – 24 . 6b.a.azhdar “impact fra cture toughness of fiber reinforced epoxy resin” ,m.sc thesis ,u.o.t ,1992 . 7dr. abbas a. al-jeebory, ali i.al-mosawi, sajed a. abdul allah “effect of percentage of fibers reinforcement on thermal and mechanical properties for polymeric composite material ” , aljournal of mechanical and materials engineering , first conference of engineering college , 2009 . 8g.dorey ,g.r.sidey and j.hutchings “impact properties of carbon fiber/ kevlar 49 fiber hybrid composites” , composites 9 (january 1978) pp.25-32. 9p.k. mallick “fiber-reinforced composites: materials, manufacturing, and design”, 3rd edition , crc press, 2007 . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 49 table(1) : some characteristic of kevlar fibers[mallick,2007] property specific strength (106m) specific stiffness (106m) density(kg/m3) value 0.254 8.8138 0.1439×104 table(2) :structure of specimens specimens number 1 2 3 resin(weight %) 80 60 40 fibers(weight %) 20 40 60 ch3 ch3 ch3 ch3 oh o o n figure (1): chemical structure of araldite resin [mallick,2007] ch2-chch2-o -c -o-ch 2-ch-ch2-o -c -o-ch 2-ch-ch2 co co nh nh figure (2): chemical structure of kevlar fibers[mallick,2007] al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 50 0 20 40 60 80 0 40 80 120 160 200 240 figure (3): impact strength reinforcing percentage (%) im pa ct s tre ng th ( k j/m 2 ) 0 20 40 60 80 0 100 200 300 400 500 figure (4): tensile strength reinforcing percentage (%) t en si le s tre ng th (m pa ) 0 20 40 60 80 0 20 40 60 80 100 reinforcing percentage (%) h ar dn es s (n /m 2 ) figure (6): hardness 0 20 40 60 80 0.0 0.4 0.8 1.2 1.6 2.0 reinforcing percentage (%) fl ex ur al s tre ng th (g pa ) figure (5): flexural strength al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 367 an improved window block correlation algorithm for code tracking in w-cdma hassan a. nasir, department of electrical engineering, university of technology, uot2007@yahoo.com abstract wide-band code division multiple access (w-cdma) is designed to offer more flexible wide band service which cannot implement by all the current cellular systems. the performance of a w-cdma is limited by the synchronous transmission that users are creating between them during transfer the information, and a result of losing synchronous properties it becomes more difficult for the users to maintain reliable communication. in this paper, an algorithm is proposed in which improved the window block correlation tracking to solve this problem. that this mechanism depends on the system estimator to calculate the threshold of error in time and determine the value of the power delay profile pdp at the point of synchronization by relying on guess the behavior of the pdp adaptively. computer simulation tests are used to examine the performance of the proposed algorithm with different channel conditions, awgn and user movement and the results show that it less complexity and faster in decision to get the synchronization as compared with the traditional algorithm. w-cdma wcdma (wbc) pdp pdp awgn hassan a. nasir 368 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 introduction spread spectrum communications is considered as a leading technology for use in wideband mobile radio systems. capitalizing on the ability of spread spectrum signals to mitigate different types of interference, such as multi-user interference and multi-path interference, spread spectrum systems enjoyed worldwide adaptation for third generation (3g) mobile radio systems (mohamed, 2010). pseudo-noise (pn) code synchronization is essential for direct-sequence spread spectrum (dsss) systems to work effectively (wern, 2004). this is very crucial since any spread spectrum based communication system requires reliable and accurate code phase timing information to de-spread the received signal and ensure satisfactory operation (mohamed, 2010). pn code synchronization has been achieved in two steps, code acquisition followed by code tracking (wern, 2004). first, during acquisition, the receiver obtains the relative delay between the received and the locally generated codes to within a chip interval. then, in the subsequent tracking phase, finer timing adjustment is performed in order to bring the residual timing error as close to zero as possible (mohamed, 2008). in this paper is concentrated on the code tracking part. in the literature, the techniques have been proposed for code tracking deals with a closed loop structure such as the delay locked loop (dll) and the tau dither loop (tdl). different types of dlls and an improved the performance of dll was efficient discussed in [(mohamed, 2010), (wern, 2004) & (wu, 2009)]. also, the window block correlation (wbc) is proposed by (asa, 2004) for code tracking and to the best of our knowledge no previous studies are available. w-cdma technology wideband wireless access based on direct sequence code division multiple access technology, the concept of w-cdma is introduction of inter-cell asynchronous operation and the pilot channel associated with each data channel. in addition, it introduces fast transmit power control (tpc) on both reverse (mobile-to-cell-site) and forward (cell-site-to-mobile) links (fumiyuki, 1998). a simplified structure of the transmission frame is depicted in figure 1. the 10ms data frame consists of 16 slots with pilot symbols at the beginning of each slot, followed by fast tpc command (fumiyuki, 1998). the configuration of w-cdma is shown in figure 2. for each user ,k  ,,...,1 kk  where k is the total number of active users. the binary data stream can be divided into data blocks, each of which consists of cn symbols. the data block for user ,k is represented by a vector, denoted by  kb , which is given by (yang, 2006).      ibb kk   cni ,...,1,  (1) the data blocked is then interleaved for mapping onto the 16 slots and modulated with quadrature phase shift keying (qpsk) and is multiplexed with pilot symbols and tpc command. the spreading waveform   tc k is of length l [(anhong, 2010) & (k. fazel, 2003)].           1 0 l l ctc k l k lttpctc (2) the rectangular pulse tcp is equal to 1 for ctt 0 and zero otherwise. ct is the chip duration, l is index to the  k lc and  k lc are the chips of the user specific. after spreading, the signal   tx k of user k is given by (k. fazel, 2003). an improved window block correlation algorithm for code tracking in w-cdma 369 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012             1 0 l l ctc k l kk lttpcdtx , dtt 0 (3) where  kd is the modulated data symbol of user k and for one data symbol duration cd ltt  . the multiplication of the modulated data sequence is done synchronously and the overall transmitted signal  tx of all k is synchronous users result in (k. fazel, 2003).         1 0 k k k txtx (4) w-cdma is designed to support a variety of data services from low to very high bit rates; multiple-rate transmission needs multiple spreading factors (sf) in the physical channels. since, the cells are assigned to different scrambling codes, each cell site can use short spreading codes independent from other cell. for example, a code tree for generation of variable length orthogonal codes is shown in figure 3, and the scramble code sequence whose length is the same as the data frame length (esmael, 1998). the impulse response of the multipath channel can be formulated as.         nn n nn tatath 1 0  (5) where a and  are the attenuation and the delay of the nth path. the received signal from the channel can be expressed as        tnthtxty  (6) where  tn is the additive white gaussian noise (awgn) and  denotes the convolution operation [(wern, 2004) & (k. fazel, 2003)]. traditional algorithm of window block correlation the window block correlation (wbc) algorithm is designed by (asa, 2004) for code tracking and to the best of our knowledge no previous studies are available. the wbc algorithm cross-correlates the known pn-sequence with the received signal and forming a vector with cross correlation values, as shown in figure 4. this vector is the window and it gives the received information about the channel and the received signal for the synchronization (asa, 2004). the traditional wbc algorithm can be done by  the tracking algorithm starts with the received signal  ty sampled with rate sr , then reduced by a factor 2n to reduce the amount of calculations. the output can be written.    cjtyjy 2  2/,...,3,2,1 nj  (7)   swp rnsfnn  , where pn the number of pilot bits is, wn is the length of the window and sf is spreading factor.  the remaining samples per chip are used for calculation of a mean value for each chip. hassan a. nasir 370 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012       2 1  jyjy ry  4/,...,3,2,1 nr  (8)  the  ry sequence is correlated with the pre-defined sequence of spread and scrambled pilot bits. the resulting sequences are called complex delay profile (cdp) and there are 15 cdps per frame.             15 1 . 1 1m sfnp r nw w mm wryrcwcdp (9) the  rcm is the spread and scrambled pilot bits in slot number m .  only 14 of the cdps are used to calculate two accumulated complex delay profiles ( acccdp ) according to (asa, 2004).    6 1 1 m mcdpacccdp (10)    14 7 2 m mcdpacccdp  the two acccdp are used to calculate a mean value called power delay profile (pdp). 2 )( 2 2 2 1 acccdpacccdp wpdp    nww ,...,3,2,1 (11)  after calculation the value of the pdp is reprocess after each shift in the window, so the sequence of the pdp has the same length as the window. finally, are mated this sequence with a certain threshold ht that depend on a number of constants and a certain amount of mean value of signal to interference ratio (sir) until that access to the point of the synchronization (asa, 2004). )12( 21            sir sirksirk th where ht is threshold,  ,,, 21 kk are constants and sir is mean value of sir . the proposed algorithm at first, it has analyzed the behavior of the pdp in different environmental of channel conditions and it has been found that the distribution of the vectors of pdps is closed in the behaviors of all these conditions with a difference in variance of distribution. it was also noted that the basic equations in the composition of the pdp has not been dependent on the other values of the pdp, and due to the central limit theorem, it is possible to estimate one behavior for the pdp with the difference of these conditions. however, to represent mathematical operation of numerical error that arises between the true and the approximation as (steven, 2002). an improved window block correlation algorithm for code tracking in w-cdma 371 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 ionapproximatvaluetrueerror  (13) in real world application, it will obviously not know the answer a priori. for these cases, the error is often estimated as the difference between previous and current approximation. thus, percent relative error is determined according to (steven, 2002). %100 ionapproximatcurrent ionapproximatpreviousionapproximatcurrent   (14) this algorithm depends on the instantaneous value of the pdp in order to timely update the value of the threshold and if this value satisfied the boundary of the error condition, the synchronization will achieve to happen, else the signal will be shifted by one sample and recalculation of the pdp to determine the time delay in the received signal: follow the steps  calculate only one value of the pdp. 2 2 2 2 1 acccdpacccdp pdp   (15)  numerical analyze taken from the use of fittingcurve to approximate mathematical equation, which represent the threshold. bpdpath  (16) where a and b are constants according to type of channel.  calculate error that arises between the threshold and pdp. %100 h h t pdpt error   (17)  if verror  , then the synchronization happen, else shifted by one sample and reprocess the operation, in which v is the percent of accepted error to achieve the synchronization. simulation parameters and results the parameters of system configuration, channel and synchronized estimator are used in the simulation can be summarized as table 1. the flowchart of the synchronized w-cdma under noisy rayleigh fading channel that utilizing the proposed algorithm is shown in figure 7. the comparison between performance of synchronized and unsynchronized w-cdma system under awgn channel is as shown in figure 5. it is clear that without achieving synchronization, it can not be obtained a performance of the system in measuring the ber even at decide to increasing the eb/no. that lead, the proposed method to achieve synchronization in nosy environment only that is an effective way and led to good results, in which has been obtained the ber=10 -4 approximately the value of eb/no at -4db. the ber performance of synchronized and unsynchronized w-cdma under rayleigh flat and selective fading with awgn is shown in figure 6. as depicted in this figure, for the proposed algorithm over rayleigh fading channel in case of flat fading, the performance is degraded with low value of eb/no also in case of frequency selective fading the performance is severely degraded, hassan a. nasir 372 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 specially with the higher of user speed movement fd. this result is closed to the result that deals with the traditional algorithm (asa, 2004). it is important to mention here that in this paper, only the uncoded w-cdma system has been considered, but it is clear that the performance can be further improved by introducing error correction codes. conclusion although the traditional method of wbc is effective and powerful way to solve the problem of the tracking phase of the synchronization, but in the environment of the channel conditions are changing slowly. as a result the process of estimation the mean value of sir and count a threshold and conformity with the vector of pdps needs time to estimate the point of synchronization or to determine the amount of delay in the received signal. as well as the environmental of channel conditions that are changing quickly affect to the process of estimation and therefore more bit error rate (ber). according to the analyses that mentioned previously a new mechanism has been fasted and less complexes to estimate the amount of timing error in the arrived signal. because this mechanism depends on the instantaneous value of the pdp to calculate the threshold of error in time, therefore it is not required to calculate a vector of pdps as compared with traditional algorithm and this need more time to determine the point of synchronization. references 1. asa c., “code tracking algorithms for wcdma in third generation mobile networks” , m. sc. thesis, department of signals, sensors and systems, royal institute of technology, stockholm, swede, 2004. 2. anhong d., “simultaneous acquisition and track scheme with multiple terminals based on subspace method for optical satellite networks”, ieee transactions on aerospace and electronic systems vol. 46, no. 1, pp. 263-277, jan. 2010. 3. esmael h. d. and bijan j., “spreading codes for direct sequence cdma and wideband cdma cellular networks”, ieee communications magazine, pp. 48-54, sep. 1998. 4. fumiyuki a., mamoru s. and hirohito s., “cdma for next-generation mobile communications systems”, ieee communications magazine, pp. 56-69, sep. 1998. 5. k. fazel and s. kaiser “multi-carrier and spread spectrum systems” john wiley & sons ltd. england, 2003. 6. mohamed g. e., “performance evaluation of a non-coherent digital delay-locked loop in rayleigh fading channels”, international journal of computer networks & communications vol. 2, no. 6, pp. 89-102, nov. 2010. 7. mohamed a. l. and ganiyu b. h., “ pulse shaping in non-coherent dll tracking of cdma signals”, wseas transactions on communications, issue 12 vol. 7, pp. 1246-1252, dec. 2008. 8. steven c. c. and raymond p. c., “numerical methods for engineers”, mcgraw-hill, new york, usa, 4 th edition 2002. 9. wern h. s., ming j. c., and cheng s. w., “performance analysis digital delay locked loop for direct sequence spread spectrum systems with doppler shift and quantized adaptation”, ieee transactions on wireless communications, vol. 3, no. 6, pp. 2108-2118, nov. 2004. an improved window block correlation algorithm for code tracking in w-cdma 373 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 10. wu y., “ code tracking for direct-sequence spread-spectrum systems under multiuser environment and multipath fading channels”, ph. d. thesis, department of electronic engineering, city university of hong kong, sep. 2009. 11. yang t., branka v. and yonghui l., “a double-stage multiuser detector with fftbased equalization for asynchronous cdma ultra-wideband communication systems”, ieee transaction on wireless communications, vol. 5, no. 11, pp. 3266-3277, nov. 2006. table 1 the parameters of system configuration, channel and synchronized estimator. wcdma system parameters number of users 7 slots per frame 16 symbols per frame 272 symbols per slot 17 symbol rate 2mhz bit rate 4mhz modulation qpsk pn-code orthogonal number of over sample 8 filter parameters type nyquist filter number of taps 21 roll off factor 0.5 channel parameters type awgn, flat, selective fading distribution rayleigh number of path 2 path attenuation level 1 st path=0db, 2 nd path=40db doppler frequency 50hz, 120hz synchronization parameters a, b for awgn 0.8087, 0.2532 a, b rayleigh & awgn 0.9391, 0.249 v for awgn, 7% v for rayleigh & awgn 9% figure 1 frame structure (fumiyuki, 1998). hassan a. nasir 374 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 figure 2 simplified block diagram of base station transceiver. figure 3 orthogonal code generation (esmael, 1998). figure 4 window blocks correlation tracking algorithm (asa, 2004). an improved window block correlation algorithm for code tracking in w-cdma 375 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 -10 -5 0 5 10 15 20 10 -4 10 -3 10 -2 10 -1 10 0 eb/no b e r with synch. without synch. figure 5 a comparisons between synchronized and unsynchronized wcdma system under awgn channel. 0 5 10 15 20 10 -4 10 -3 10 -2 10 -1 10 0 eb/no b e r selective (fd=120) synch. flat (fd=50) synch. fading without synch. figure 6 ber performance of synchronized and unsynchronized wcdma system under flat and selective fading with awgn channel. hassan a. nasir 376 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 367-376, year 2012 figure 7 flowchart of investigated w-cdma system under noisy rayleigh fading channel with the proposed wbc algorithm. 5-4-2010.pdf \(microsoft word \\316\\307\\341\\317 4\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 38 extraction of nickel from fly ash of heavy oil using ammonium hydroxide khalid m. mousa israa shakir m. ali, hind j. hadi lecturer, college of engineering assistant lecturer, college of engineering al-nahrian university al-nahrain university abstract an experimental investigation to recover the nickel from ash of residue of fire power station using ammonium hydroxide was conducted. the experiments were conducted in 0.6 l glass baffled reactor with multi speed mixer. the effect of different rotational velocities studied ( 200, 400, 600, 800 and 1000 rpm ) and different temperatures were ( 50, 60, 70 and 80)ºc and it was found that the recovery of nickel increased with increasing rotational velocity till the 600 rpm while there is no change in nickel recovery with increasing temperature till 70 ºc. controlling steps were investigation and it was found that the transfer through the film surrounding the particle (interphase) is the controlling step. keywords: nickel, fly ash, ammonium hydroxide, extraction استخالص النيكل من الرماد المتطاير من الوقود الثقيل باستخدام هيدروكسيد االمونيوم هند جاسم هادي. م.م، اسراء شاكر محمد علي . م.م خالد مخلف موسى . د كلية الهندسة/ قسم الهندسة الكيمياوية/ كلية الهندسة مدرس مساعد/ قسم الهندسة الكيمياوية / مدرس جامعة النهرين جامعة النهرين الموجز تضمن هذا البحث دراسة امكانية اسـتخالص النيكـل مـن مخلفـات حـرق الوقـود الثقيـل المسـتخدم فـي انتـاج الطاقـة الكهربائيــة بأســتخدام محلــول هيدروكســيد االمونيـــوم حيــث تــم اجــراء مجموعــة مـــن التجــارب عــن طريــق اســـتخدام و ٨٠٠، ٦٠٠، ٤٠٠، ٢٠٠سـرع مختلفـة حيـث تـم اسـتخدام مللتر مزود بخالط ذا ٦٠٠مفاعل زجاجي حجمة و ٧٠، ٦٠، ٥٠دورة في الدقيقة و كذلك تم اجراء مجموعة من التجارب باستخدام درجات حرارة مختلفة ١٠٠٠ كمــا تــم دراســة الخطــوة المحــددة ، درجــة ســيليزية وقــد بينــت النتــائج امكانيــة اســترداد النيكــل و بنســب عاليــة ٨٠ . بانها انتقال المادة من الطور البيني المحيط بالمادة الصلبةلالنتاج و ظهر introduction: nickel is an important alloying metal used in all branches of metal industry. it imparts to alloys toughness, strength, and lightness, and anti-corrosion, electrical and thermal qualities. the weight percent of nickel in the oil-fired fly ash, about 1-2%, so it is a considerable source compared with that of natural minerals sources, and due to this reason international attention was conducted to recover the nickel from this source earlier (tsai, 1998) .the processing of nickel recovery depending on the characteristics of the burned oil and the place of ash formation. recovery of nickel from fly ash can be achieved by acid using 30 % h2so4, or water leaching (stas, 2007). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 39 (tsai, 1998) discussed the experimental extraction of vanadium and nickel from oil-fired fly ash. the results indicated that leaching of oil fired fly ash in 0.5 n of sulfuric acid lead to extracted 60% of ni. when leached in 2 n sodium hydroxide solutions the extraction of nickel was negligible. (othman,1999) studied the recovery of metals from spent catalyst using sulfuric acid and selective precipitation of nickel from other metals by an addition of sodium hydroxide. it was found that sulfuric acid as a leaching agent resulted significantly higher nickel concentration compared to nitric and hydrochloric acids, sodium hydroxide was used to adjust the ph of the solution. at the best ph, more than 80% of nickel recovery was obtained. after some preliminary tests, (stas, 2007) used two leaching stages of fly ash to recover vanadium, molybdenum and nickel. first stage was an alkaline leaching of fly ash to recover vanadium and molybdenum followed by a second stage using sulfuric acid leaching of the residual ash to recover nickel. (emad, 2007) studied the extraction of nickel using the hydrometallurgy method. the author recovered nickel from the residues using sulfuric acid and the result obtained showed the possibility of obtaining the highest recovery at acid concentration 3 m, temperature=100 c, time of leaching 90 min and s/l ratio 5 gm/l. it can be understood from above recovery methods that hydrometallurgical methods are widely used. procedures such as solvent extraction, ion exchange, and crystallization are employed to recover rare metals such as nickel. leaching is concerned with the extraction of a soluble constituent from a solid by means of a solvent. the process may be used either for the production of a concentrated solution of a valuable solid material, or in order to remove an insoluble solid, such as pigment from a soluble material with which it is contaminated by the proportion of soluble constituent, present, its distribution throughout the solid, the nature of the solid and the particle size (coulson, 2002). in the leaching of soluble materials from inside a particle by a solvent, a general steps can occur in the overall process. the solvent must be transferred from the bulk solvent solution to the surface of the solid. next, the solvent must penetrate or diffuse into the solid. the solute dissolves into the solvent. the solute then diffuses through the solid solvent mixture to the surface of the particle. finally, the solute is transferred to the bulk solution. many different phenomena encountered make it almost impracticable or impossible to apply any one theory to the leaching action (geankoplis, 1993). factors influencing the rate of extraction are particle size, which is influences the extraction rate in a number of ways. solvent, the liquid chosen should be a good selective solvent and its viscosity should be sufficiently low. temperature, in most cases, the solubility of the material which is being extracted will increase with temperature to give a higher rate of extraction. agitation of the fluid, it is important because this increases the divergence diffusion and therefore the transfer of material from the surface of the particles to the bulk of the solution (coulson, 2002). the mass transfer coefficient determines the rate of mass transfer across a medium in response to a concentration gradient. there are two main mechanisms depending on whether the flow is laminar or turbulent (grisafi, 1998). equation (1) is used for the mass transfer determination (coulson, 2002): (1) where: m mass of solute transferred in time t, t time, a is the area of the liquid-solid interface, b is the effective thickness of the liquid film surrounding the particles, k diffusion coefficient, cs is the concentration of the saturated solution in contact with the particles, c is the concentration of the solute in the bulk of the solution at time t (coulson, 2002). the presence or absence of turbulence can be correlated with impeller. (geankoplis, 1993) defined reynolds number nre, as: nre= (2) where: al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 40 da is the impeller (agitator) diameter in m, n is rotational speed in rev/s, ρ is fluid density in kg/m 3, and µ is the viscosity in kg/m.s. many previous researchers used acidic leaching to recover metals, such as v, ni, fe, ---etc. from waste ash, all of them are neglected the effects of corrosion on equipments. the aim of this work is to study the best conditions and then find the controlling step to nickel recovery from fly ash of produced from heavy oil-fired electrical power station due to a limited source of nickel in iraq and to overcome the problem of corrosion. experimental work fly ash were collected from boilers of al-dora thermal power station in south of baghdad. prior to leaching, a mass of ash was ground and mixed for 12 h. in laboratory ball mill, then the sample was analyzed for nickel content by atomic absorption spectrometry and the average percentage was found to be 1.51wt % .ammonium hydroxide nh4oh (1n) was used as leaching agent , which is prepared from ( 25 %) nh3 supplied by scharlau. experimental apparatus first of all the characteristics of reactor was studied carefully and the design was implementation. experiments were carried out in (600 ml.) glass baffled reactor, the diameter of glass reactor was 9.5 cm and height of 12 cm with three rectangular baffles of 0.8 cm thickness, and 1.5 cm width. to insure a homogeneous distribution of temperature water bath with controller of temperature to heat the solution to the required temperature (50-80 ºc) was used. the reactor was supplied by a mixer consisted of stainless steel shaft, screwed with three blades impeller, the diameter of the impeller was 3 cm. the stirrer rotated by means of an electrical motor to achieve the required velocity. the mixer was screwed with stand and two hands to infixing mixer and thermometer (with range 0-250 ºc). the motor of mixer and water bath was connected to controller. in each experiment 80 g of ash was added to 400 ml. of 1 n ammonia solution and heated using water bath with different temperatures and stirred with different speeds (rpm), after one hour the solution was filtered and analyzed for nickel content by means of atomic absorption spectrometry. figure 1 shows the schematic diagram of the experimental apparatus. results and discussion: experiments were carried out for 1 h. at 80 ºc with different agitation speed (200,400, 600, 800, and 1000) rpm to study the effect of agitation speed on nickel recovery. figure 2 showed that the recovery of nickel depend on the agitation speed, 1.1 g/l was recovered at 400 rpm and increased with increasing agitation speed, for 600 rpm the recovery was 2.86 g/l, so the best value of recovery is at 600 rpm. above this speed the recovery doesn’t increase further. this result indicates that the dominant resistance of the leaching process is the mass transfer from the particles surface to the surrounding medium. agitation is important because it increases the eddy diffusion and therefore increases the transfer of material from the surface of the particles to the bulk of the solution (coulson, 2002). figure 3 shows the effects of reynolds number on the mass transfer coefficient. it is clearly that the mass transfer coefficient increased with increased reynolds number, this can attributed to as turbulent flow is involved, and the turbulent-eddies act as a transport mechanism giving rise to transport rates that may be orders of magnitude higher than those due to molecular effects (grisafi, 1998). the effect of temperature on nickel recovery was studied; experiments were conducted for 1 h, and 600 rpm, s/l ratio 1/5 and for different temperatures (50, 60, 70, and 80) ºc. figure 4 showed that the nickel recovery is not affected by temperature till 70 c and then a shift in nickel yield was occur between 70 ºc to 80 ºc, one can conclude that the controlling step of this process may changed from mass transfer control to kinetic control because according to the arrhenius law the rate of reaction is increased with temperature of the process. if the intra-particle diffusion or kinetic of the process is the dominant resistance, the nickel recovery should be depends on the temperature, al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 41 the intra-particle diffusion is influenced by temperature, because it affects on the diffusion coefficients (leavenspile, 1999) and (luis, 2000). figure 4 shows the comparison of this work with (stas, 2007) at different temperatures. in this work 94.7 % of nickel was recovered when using 1 m nh4oh, (s/l) ratio =1/5, temperature= 80ºc after 1h. while (stas, 2007) recovered about 76% of nickel using [h2so4] =5m, (s/l) =1/5, temperature 80ºc after 4h. conclusions: 1. the resedue of fired power station is a good source of nickel. 2. the recovery of nickel from ash via nh4oh was successful conducter. 3. the best agitation speed for this process is 600 rpm. 4. a controlling step of this process was changed from mass transfer controlling step to kinetic controlling step. references: [1]coulson j.m and richardson j.f (2002) "chemical engineering", vol. 2, bath press, 5th edition, p 375376. [2]geankoplis,ch.,j.(1993) "transport process and unit operations", printice-hall international, inc., university of minnesota., 3rd edition, p 144, p 725. [3]grisafi,f.,brucato,a.,rizzuti,l.(1998) "solid-liquid transfer coefficients in gas-liquid-solid system agitated vessels", the canadian journal of chemical engineering, vol. 76, issue 3, pages 446455, june. [4]leavenspile(1999) " chemical reaction engineering ", john-wiley and sons ind., 3rd edition, p 582 , new york. [5]luis etal, (2000), "vanadium recovery by leaching in spent catalysts for sulfuric acid production", science and technology. vol. 8, no. 16, p. 85-90. [6]othman, h.b.mat. and yuliusman, (1999), " selective nickel recovery from spent catalyst". world engineering congress and exhibition (wec 99); kuala lampur, july 19-22. [7]stas, j., dahduh,a. , al-chayah,o., (2007), " recovery of vanadium, nickel and molybdenum from fly ash of heavy oil-fired electrical power station", chemical engineering, 51/2, 67-70, syria. [8]tsai, s.-l., tsai, m.-s., (1998), “a study of the extraction of vanadium and nickel in oil-fired fly ash," conservation and recycling, 22, pp. 163-176, china. [9] لاستخfص النيكل من مخلفات حرق الوقود الثقي" )٢٠٠٧( مؤيد كاصد جلھوم، ليث يوسف يعقوب. عماد ايوب يوسف، د ٣د العد ق، ملح٢٥، مجلة الھندسة و التكنولوجيا، المجلد "باrذابة المائية و ترسيب فلزه كھربائيا al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 42 figure 1 a schematic diagram of the experimental apparats 1-glass reactor, 2impeller, 3shaft, 4motor, 5stand, 6water bath, 7-baffle 200.00 400.00 600.00 800.00 1000.00 rpm 0.50 1.00 1.50 2.00 2.50 3.00 re co ve ry ( g /l ) figure 2 effect of agitation speed on nickel recovery at t=80 ºc al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 43 0.00 200.00 400.00 600.00 800.00 1000.00 re 0.50 1.00 1.50 2.00 2.50 3.00 (( k a )/ b )* 1 0 ^5 figure 3 effect of re number on mass transfer coefficient figure 4 comparison with results of (stas, 2007) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 548 effect of aggregate properties on hot mix asphalt performance romel nano yaqob university of kirkuk/civil engineering department e-mail: eldadoner@yahoo.com abstract mineral aggregates make up 90 to 95% of a hma mix by weight or approximately 75 to 85% by volume. the properties of the mineral aggregates have significant affects in performance of our local roadways which offers the possibility of investment in these properties towards resisting different ranges of external applied loads and environmental conditions. for this reason, the performance properties susceptibility due to aggregate properties (consensus and source) is going to be evaluated with a wide range of blends, fine, medium and coarse gradation mixtures. the selected source property in this study was toughness (% abrasion), and the consensus property used in this study was angularity (% crushed). results show that the medium graded mixtures were more susceptible in terms of marshall stability due to the change in % abrasion and % crushed aggregate, while the coarse graded mixtures were more susceptible in terms of marshall flow due to the change in % abrasion and % crushed aggregate. keywords: % los angeles abrasion, %crushed, marshall stability, marshall flow, air voids تأثير خواص الركام على اداء الخلطة االسفلتية الحارة روميل ننو يعقوب قسم الهندسة المدنية\كركوك جامعة الخالصة ونوعية الركام . من وزن الخلطة % 95 الى 90من حجم الخلطة االسفلتية الحارة و % 85الى % 75يشكل الركام حوالي وى ، والذي يوفر امكانية استثمار هذه الخواص باتجاه مقاومة مختلف مديات القالمعدني له تاثير كبير على اداء طرقنا المحلية لهذا السبب اصبح من الضروري تقييم تأثرية الخواص االدائية للخلطة االسفلتية نتيجة . المسلطة الخارجية والظروف البيئية باستعمال مجال واسع من التدرجات الناعمة ) الخواص المصدرية والخواص المتفق عليها( التغيير في خواص الركام وفي هذه الدراسة تم تقييم خاصية المصدر باالعتماد على خاصية القساوة وتقييم .والخشنة) الكثيفة( والمتوسطة النعومة mailto:eldadoner@yahoo.com al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 549 اظهرت نتائج الدراسة بان الخلطة االسفاتية ذات التدرج الكثيف تتأثر بشكل اكبر . خاصية الركام المتفق عليها وهي التزاوي ت التدرج الخشن فقد اظهرت تاثرية اكبر عند تغيير اما الخلطة االسفلتية ذا. بتغيير خواص الركام من ناحية ثباتية مارشال . خواص الركام من ناحية جريان مارشال intruduction asphalt concrete (ac) is a heterogeneous material that consists of asphalt cement, natural or artificial aggregate, mineral filler, additives and air voids. aggregate comprise the vast bulk of paving mixture and therefore, exert significant influence on the resulting engineering properties of the structure. the fundamental measurements of aggregate morphological properties (angularity, shape, surface texture and toughness) are essential for good quality control of aggregates and for understanding the influence of these properties on the behavior of asphalt (khandhal and parker, 1998). in astm d8 ( astm 2003), aggregate is defined as " a granular material of mineral composition such as sand, gravel, shell, slag, or crushed stone, used with cementing medium to form mortars or concrete or alone as in base course, railroad ballasts, etc." (fwa, 2006). objective and test plan the objective of this study was to evaluate the effect of aggregate properties (toughness and angularity) on marshall properties for hma mixture (stability, flow, and air voids). to accomplish this, various mixtures were compacted with optimum asphalt content and three different gradation types. variable values of percent los angeles abrasion (source property) were used throughout this study which refers to the different quarry in iraq. different percentages of crushed aggregate (consensus property) were also used for all three gradation types. the same compactive effort 50 blows/face was used to determine their volumetric and performance-related properties. in order to consider a range of mixtures, three blends of fine, medium and coarse gradations limited by the astm specification for gradation were used and shown in figure 1. three source of aggregates from al-nebaey, daqooq, and al-akhaither were used and their determined properties were shown in table 1, and one grade (40-50) penetration graded of asphalt cement were utilized from daurah refinery, and its properties were shown in table 2. coarse aggregate properties: coarse aggregate is the material, which is substantially retained on no. 4 sieve (2.365 mm). generally, the asphalt concrete mixture contains from 35-65 percent of coarse aggregate for a nominal maximum size of 19.0 mm. this content normally gives a suitable texture for a heavily trafficked road (astm, 2003). the most significant properties of graded coarse aggregate to be used in the manufacture of asphaltic mixtures are: (superpave, 1994) a. consensus properties which are critical properties required to develop a desirable hma mix. these properties are: flat and elongated particles al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 550 aggregate angularity ( coarse and fine) clay content b. source properties, which are critical also, including: effective specific gravity and asphalt absorption. toughness soundness deleterious materials mineral composition two significant important properties were considered as factors affecting the performance of hma mix. coarse aggregate angularity coarse aggregate angularity is defined as the percent by weight of aggregate retained on the no.4 (4.75 mm) sieve with one or more fractured face. this property is determined using astm d5821 "standard test method for determining the percentage of fractured particles in coarse aggregate" (astm, 2003). this property ensures a high degree of aggregate internal friction and rutting resistance. the hma mixtures containing different aggregates types were evaluated by ishai and gelber for marshall stability and flow, resilient modulus, and split tension strength. the results showed that there was a significant increase in the stability with the increase in the geometric irregularities of the aggregates. there was no correlation between geometric irregularities and resilient modulus or split tension strength of the hma mixtures. (ishai and gelber, 1982) in 1962, huang developed the particle index test for evaluating particle shape and surface texture. particle index is determined by rodding aggregate in a mold and determining the voids. the particle index is then derived as follows: (huang, 1962) ia = 1.25 v10 -0.25 v50 – 32% (1) where; ia= the particle index value v10= % voids in the aggregate sample compacted with 10 blows per layer v50= % voids in the aggregate sample compacted with 50 blows per layer the results indicate that the test method is capable of distinguishing the difference between natural rounded and rough angular aggregate by increasing particle index value. this test has been standardized as astm d3398, index of aggregate particle shape and texture. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 551 toughness (% l.a. abrasion) toughness is the percent of material from an aggregate blend during the los angeles abrasion test. this property is determined using (astm c131) "standard method of test for resistance to degradation of small-size coarse aggregate by abrasion and impact in the los angeles machine". this test provides some indication of the aggregate's ability to resist degradation from processes that it would encounter through its life as an aggregate in hma. hma aggregates can be degraded during stockpiling, processing (through a hma plant), placing, compacting, and may due to traffic loads. aggregate which lack adequate toughness and abrasion resistance may cause construction and performance problems. degradation occurring during production can affect the overall gradation, and thus, widen gap between properties of the laboratory designed mix and field production [yiping, et.al, 1998]. results of experimental work the optimum asphalt content by the marshall mix design method for three blend mixtures, and designations for each mixture used in the remaining discussion are provided in table 3. effect of los angeles abrasion of aggregate mixture performance to percent of wear variation is illustrated in figures (2,3,4) for the three target mixtures considered (fine, medium, and coarse). over an increase of percent los angeles abrasion from (12.1-to-20.1-to-26.5), the medium gradation mixture was more susceptible to increase in percent los angeles abrasion of aggregate. changing the percent los angeles abrasion from 12.1 to 26.5 revealed a decrease in marshall stability by 1.88 kn, whereas, the coarse gradation shows less susceptibility and reveals less decrease in marshall stability by 0.93 kn, as shown in figure 2. figure 3 shows that the increase of percent los angeles abrasion of aggregate will decrease the marshall flow for all gradation mixtures used in this study. the medium gradation mixture revealed less decrease in marshall flow (about 0.26 mm) than do the coarse gradation mixture which decreased by 0.428 mm. figure 4 shows the effect of percent los angeles abrasion of aggregate to % air voids. in this figure the fine gradation mixture revealed less decrease in % air voids and the variance was 0.15 % , while the coarse and medium gradation show more variation in % air voids, which revealed as twice as the fine gradation reveals. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 552 effect of crushed of aggregate mixture performance to percent of crushed aggregate variation is illustrated in figures (5,6,7) for the three target mixtures considered (fine, medium, and coarse) gradations. figure 5 shows that the an increase of percent crushed in aggregate from 0 % -to20 % to – 40 % will increase the marshall stability for the three gradation mixtures, and the medium gradation mixture was more influenced by the increase in % crushed, and the variance was 1.4 kn. while the coarse graded mixture shows less influencing to the increase in % crushed, and the variance was 0.72 kn figure 6 shows that the increase of %percent crushed in aggregate from 0 % 20 % to – 40 % will decrease the marshall flow for all gradation mixtures used. fine and medium graded mixtures show less susceptibility to the change in percent crushed and the decrease was about 0.22 mm as average, while the coarse graded mixture was more susceptible to the increase in percent crushed in aggregate, and the change in marshall flow was 0.42 mm. figure 7 shows that the increase of percent crushed in aggregate from 0 % 20 % to – 40 % will decrease the percent air voids for all gradation mixtures used in this study. the results show that the fine graded mixture was more susceptible to the change in percent crushed of aggregate, and the decrease value was 0.96 %, while the coarse graded mixture shows less susceptibility to the change of % crushed and the value of the decrease was 0.68 % conclusion within the limitations of materials and test used in this study the following conclusions are drawn: 1the medium graded mixtures were more susceptible to the increase of percent los angeles abrasion, measured by the marshall stability. 2the course graded mixtures evaluated were more susceptible to the increase of percent los angeles abrasion, measured by the marshall flow and percent air voids. 3the medium graded mixtures were more susceptible to the increase in percent crushed aggregate, measured by the marshall stability. 4the coarse graded mixtures were more susceptible to the increase of percent crushed, as measured by the marshall flow. 5 the fine graded mixture was more susceptible to the increase in percent crushed aggregate, measured by the percent air voids. references 1astm, 2003. annual book of astm standards. volume 04.03 2huang, e. y. "a test for evaluating the geometric characteristics of coarse aggregate particles" proceeding american society of test and material, 62:1223-1242, 1962. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 553 3iraqi standard specification for road and bridges, republic of iraq, ministry of housing and construction, state commission of roads and bridges, department of planning and studies, 2003. 4ishai, i. and gelber, h. “effect of geometric irregularity of aggregates on the properties and behavior of asphalt concrete,” association of asphalt paving technologists, vol. 51. 1982 . 5khandhal, p. s. and parker, f. jr. (1998) " aggregate tests related to asphalt concrete performance in pavement program", transportation research board, nchrp report 405. 6standard specification for roads and bridges, state organization of roads and bridges, republic of iraq, ministry of housing and construction, revised edition (2003). 7superpave asphalt mixture design & analysis. national asphalt training center demonstration project 101. federal highway administration office of technology application, washington, dc, 1994. 8t. f. fwa, "the handbook of highway engineering", taylor and francis group, 2006. crs press in an imprint of taylor & francis group, 6000 broken sound parkway nw, suite 300, usa. 9yaqob. r. n., "influence of avoiding the superpave restricted zone on asphalt concrete performance", m.sc., thesis, university of baghdad, baghdad, 2004. 10yiping, wu, parker, f. and kandhal, k. "aggregate toughness/abrasion resistance and durability/ soundness test related to asphalt concrete performance in pavements", transportation research board, trb, national research council, washington, 1998. table 1: physical properties of aggregate. *: iraqi standard specification for roads and bridges table 2: physical properties of asphalt cement (yaqob, 2004) test unit astm results d(40-50) penetration 250 c, 100 gm, 5 sec. 1/10 mm d 5 42 absolute viscosity at 60 0 c poise d 2171 3068 kinematic viscosity at 135 0 c c st. d 2170 373 ductility (25 0 c, 5 cm/min.) cm d 113 > 100 softening point (ring & ball) c0 d 36 51.0 properties astm sorb* alakhaither nebaey daqooq bulk specific gravity c 127 2.639 2.568 2.614 % wear ( l.a. abrasion) c 131 <=35 12.1 26.5 20.1 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 554 6 7 8 9 10 11 12 10 12 14 16 18 20 22 24 26 28 percent los angeles abrasion m ar sh al l s ta b ili ty , k n fine gradation medium gradation coarse gradation specific gravity at 250 c ……. d 70 1.04 flash point ( cleveland open cup) c0 d 92 332 after thinfilm oven test penetration of residue 1/10 mm d 5 39 ductility of residue cm d 113 82 loss on heat at 1350c, 50 gm, 5 hrs % d 1754 0.82 table 3: type of aggregate gradation and optimum asphalt content for mixtures gradation type (sorb) optimum ac (%) designation lower limit ( coarse) 4.6 coarse average limit (medium) 4.9 medium upper limit (fine) 5.2 fine figure 2: marshall stability variation due to changes in percent los angeles abrasion al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 555 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 10 12 14 16 18 20 22 24 26 28 percent los angeles abrasion m ar sh al l f lo w , m m fine gradation medium gradation coarse gradation 3 3.2 3.4 3.6 3.8 4 4.2 10 12 14 16 18 20 22 24 26 28 percent los angeles abrasion p er ce nt a ir v oi ds fine gradation medium gradation coarse gradation figure 3: marshall flow variation due to changes in percent los angeles abrasion figure 4: percent air voids variation due to changes in percent los angeles abrasion al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 556 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 0 5 10 15 20 25 30 35 40 45 percent crushed (2 face or more) m ar sh al l s ta bi lit y, k n fine gradation medium gradation coarse gradation 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 0 5 10 15 20 25 30 35 40 45 percent crushed ( 2 face or more) m ar sh al l f lo w , m m fine gradation medium gradation coarse gradation figure 5: marshall stability variation due to changes in percent crushed of aggregate figure 6: marshall flow variation due to changes in percent crushed of aggregate al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 557 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 0 5 10 15 20 25 30 35 40 45 percent crushed (2 face or more) p er ce nt a ir v oi ds fine gradation medium gradation coarse gradation figure 7: percent air voids variation due to changes in percent crushed of aggregate template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 133 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. a study of the effect of parameters on the stress in helical spring wire anahed hussein jebur, al-qadisiyah, university, department of mechanical engineering, al-qadisiyah,, iraq. email: aaa56h@yahoo.com received on 21 june 2017 accepted on 23 january 2017 abstract: the stress of the helical spring changes with several parameter are studied using (solidworks2014) program. the stress effect is by coil diameter (d) and the shape of section of the helical spring wire (circular ,rectangular and square) for the same diameter, where the stress on the helical spring wire increases by increasing the coil diameter (d), also the stress on the helical spring wire affect by changing the shape of the spring wire section . 1. introduction a spring is defined as an elastic body, whose function is to distort when loaded and to recover its original shape when the load is removed. the various important applications of springs are as follows :[1] 1. to cushion, absorb or control energy due to either shock or vibration as in car springs , railway buffers, air-craft landing gears, shock absorbers and vibration dampers 2. to apply forces, as in brakes, clutches and spring loaded valves. 3. to control motion by maintaining contact between two elements as in cams and followers 4. to measure forces, as in spring balances and engine indicators. 5. to store energy, as in watches, toys, etc. [2] 1.2. helical spring the helical springs are made up of a wire coiled in the form of a helix and is primarily intended for compressive or tensile loads. the cross-section of the wire from which the spring is made may be circular, square or rectangular. the two forms of helical springs are compression helical spring as shown in fig. (a) and tension helical spring as shown in fig. (b).[3] 1.3. the aim of research 1study the effect of changing the shape of the spring section ( circular , rectangular , square ) on the stresses generated in the spring wire and calculate the maximum shear stress. mailto:aaa56h@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 134 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2-study the effect of changing the coil diameter for the helical spring on the stresses generated in the spring wire and calculate the maximum shear . fig.(a) fig.(b) 2. theoretical derivation of shear stress in the helical spring wire 2.1. for circular spring section : we have found out the direction of the internal torsion t and internal shear force f at the section due to the external load f acting at the center of the coil. the cut sections of the spring, subjected to tensile and compressive loads respectively, are shown separately in the fig(c). the broken arrows show the shear stresses (τt ) arising due to the torsion t and solid arrows show the shear stresses (τf) due to the force f. it is observed that for both tensile load as well as compressive load on the spring, maximum shear stress (τt + τf) always occurs at the inner side of the spring. hence, failure of the spring, in the form of crake, is always initiated from the inner radius of the spring.[4] the radius of the spring is given by d/2. note that d is the mean diameter of the spring. the torque t acting on the spring is : t=(f*d)/2…………(1) if d is the diameter of the coil wire and polar moment of inertia, ip = πd^4)/32 the shear stress in the spring wire due to torsion is τt =tr/ip = ((f*d)/2*d/2)/ ((πd^4)/32) = 8fd/(πd^3 )………(2) average shear stress in the spring wire due to force f is τf = f/(π d^2/4)= 4f/(πd^2 )………….(3) figure (c) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 135 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. therefore, maximum shear stress the spring wire is τt + τf =8fd/(πd^3 )+4f/(πd^2 ) ………..(4) or τmax = 8fd/(πd^3 ) [ 1+ (1/(2d/d)) ]………..(5) or τmax = 8fd/(πd^3 ) [ 1+(1/2c) ] , where c= d/d is called the spring index. finally τmax = ( ks8fd/(πd^3 )) where, ks = 1+(1/2c) the above equation gives maximum shear stress occurring in a spring. ks is the shear stress correction factor. [5] 2.2. for rectangular spring section : if a , b is the length and width respectively of the spring wire section , the polar moment of inertia ip = ((b a^3)/12) the torque t acting on the spring is : t=f d/2…………(1) the shear stress in the spring wire due to torsion is τt = (t*r)/ip = t *(a/2)/( (ba^3)/12) = 6t/(ba^2 )……………(2) τt = (6f*(d/2) )/(ba^2 ) = (3f*d)/(ba^2 ) ……………(3) average shear stress in the spring wire due to force f is τf = f/a = f/(b*a)…………(4) therefore, maximum shear stress the spring wire is τmax = τt + τf = (3f*d)/(ba^2 ) + f/(b*a) τmax =(3f*d)/(ba^2 ) [ 1 + ( 1/ ( 3 d/a)) ] where d/a = c τmax = (3f*d)/(ba^2 ) [ 1 +(3 1/c )]…………(5) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 136 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.3. for square spring section : if a is the length of the spring wire section , the polar moment of inertia , ip = a^4/12 and d = (a/2) , the torque t acting on the spring is : t = (f*d)/2……..(1) the shear stress in the spring wire due to torsion is τt = (t*r)/ip = ( (t* a)/2) / ( a^4/12) = 6t/a^3 τt = (6f d/2)/a^3 = 3fd/a^3 ……………(2) average shear stress in the spring wire due to force f is τf = f/a= f/a^2 ………….(3) therefore , maximum shear stress the spring wire is τmax = τt + τf = 3fd/a^3 + f/a^2 τmax = 3fd/a^3 [ 1 + ( 1 / ( 3* ( d/a)) ]…………..(4) where d/a = c τmax = 3fd/a^3 [ 1 + 1/3c]……….(5) all quantities in above equations are now known. steel aisi 1020 material database. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 137 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.4. theoretical solution : 2.4.1. circular cross section d= 30 mm d = 8 mm f= 100 kn τmax = τmax = 8fd/(πd^3 ) [ 1+(1/2c) ] τmax = [ ( 8*100*0.03) / π (0.008)^3 ] * [ 1+ ( 1 / ( 2* (0.03/0.008) ) ] = 16910212 .7 n/m^2 d= 40 mm d = 8 mm f= 100 kn τmax = [ ( 8*100*0.04) / π (0.008)^3 ] * [ 1+ ( 1 / ( 2* (0.04/0.008) ) ] = 19894367.89 n/m^2 d= 50 mm d= 8 mm f= 100 kn τmax = [ ( 8*100*0.05) / π (0.008)^3 ] * [ 1+ ( 1 / ( 2* (0.05/0.008) ) ] = 26857396 .65 n/m^2 2.4.2. square cross section d= 30 mm a = b = 8 mm f= 100 kn τmax = 3fd/a^3 [ 1 + ( 1 / ( 3* ( d/a)) ] τmax = [ ( 3*100*0.03) / ( 0.008)^3 ] * [ 1+ ( 1 / ( 3* (0.03/0.008) ) ] = 19140625 n/m^2 d= 40 mm a = b = 8 mm f= 100 kn τmax = 3fd/a^3 * [ 1+ (1/(3d/a) ] τmax = [ ( 3*100*0.04) / ( 0.008)^3 ] * [ 1+ ( 1 / ( 3* (0.04/0.008) ) ] = 25000000 n/m d= 50 mm a = b = 8 mm f= 100 kn τmax = 3fd/a^3 [ 1 + ( 1 / ( 3* ( d/a)) ] τmax = [ ( 3*100*0.05) / ( 0.008)^3 ] * [ 1+ ( 1 / ( 3* (0.05/0.008) ) ] = 30859375 n/m^2 2.4.3. rectangular cross section d= 30 mm a =8 mm b = 6 mm f= 100 kn τmax =(3f*d)/(ba^2 ) [ 1 + ( 1/ ( 3 d/a)) ] τmax = [ ( 3*100*0.03) / (0.006)(0.008)^2 ] * [ 1+ ( 1 / ( 3*(0.03/0.008) ) ] = 25520833 n/m^2 d= 40 mm a =8 mm b = 6 mm f= 100 kn τmax = [ ( 3*100*0.04) / (0.006)(0.008)^2 ] * [ 1+ ( 1 / ( 3*(0.04/0.008) ) ] = 33333333 n/m^2 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 138 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. d= 50 mm a =8 mm b = 6 mm f= 100 kn τmax = [ ( 3*100*0.05) / (0.006)(0.008)^2 ] * [ 1+ ( 1 / ( 3*(0.05/0.008) ) ] = 41145833 n/m^2 3. analysis setup a three dimensional helix was created and meshed in solid works 2014 . under these condition , static study advisor and one fixed end and one free end and constant load. the available design parameters of the helical to be the wire diameter (d) and the coil diameter (d) the helix diameter measured from the wire centerline . pitch of spring (p) is 12 mm and the number of revolutions (n) is 6 . for the three type of spring section (circular, rectangular,square) the helical spring parameters were taken from an existing prototype with parameters in tables (1-a) ,(1-b) and (1-c) respectively. figure (1) : helical spring parameter . table (1-a) circular parameter table (1-b) square parameter table(1-c) rectangular parameter using the boundary conditions of one fixed end and one free end and constant load as show in figure (2-a) and (2-b) . d a*a n τmax 30 8*8 6 95181256 40 8*8 6 114110088 50 8*8 6 142575808 d a*b n τmax 30 8*6 6 51650756 40 8*6 6 75681192 50 8*6 6 93188664 d d n τmax 30 8 6 80914616 40 8 6 114889872 50 8 6 128394864 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 139 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure ( 2-a ) figure ( 2-b ) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 140 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4. analyses models 4.1. for circular spring section : for d = 30 mm for d = 40 mm for d = 50 mm figure (3-a) figure (3-b) figure (3-c) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 141 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.2. for square spring section : for d = 30 mm for d = 40 mm for d = 50 mm figure (4-a) figure (4-b) figure (4-c) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 142 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.3. for rectangular spring section : for d = 30 mm for d = 40 mm for d = 50 mm figure (5-a) figure (5-b) figure (5-c) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 143 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. discussion : according to results of the modeling analysis we notice in figure (6-a) that in which we calculate the maximum stresses on the spring of circular cross section , where the stress is increase by increasing the coil diameter (d) , the lowest stresses are appearing in this section since it is suitable for the most application . in figure (6-b) that in which we calculate the maximum stresses on the spring of square cross section , where the stress is greater than that in circular , in figure (6-c) that in which we calculate the maximum stresses on the spring of rectangular cross section , where the stress is highest of the three sections because of the edges and corners that rises the stresses of the rectangular cross section as compared with the circular and rectangular cross section . figure (6-a) von-mises stresses of circular section for five node figure(6-b) von-mises stresses of section of square for five nodes figure(6-c) von-mises stresses of rectangular for five nodes vs. three diameter figure (6-a) von-mises stresses of circular section for five node al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 144 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. in figure (7-a) that in which we calculate the maximum stresses on the spring for it is three types for the same coil diameter (d=30) , where the highest stress is appear in the rectangular section and the lowest stress in the circular section , this is due to the shape of the spring section where the circular section has not edges and angles , and the area of the rectangular spring less than the square spring section . in figure (7-b)that in which we calculate the maximum stresses on the spring for it is three types for the same coil diameter (d=40) , where the stress is increases by increasing the coil diameter. in figure (7-c) that in which we calculate the maximum stresses on the spring for it is three types for the same coil diameter (d=50) , where the greatest stress is appearing with the greater coil diameter . figure(7-a) von-mises stresses of constant coil diameter d=30 for three spring section figure(7-b) von-mises stresses of constant coil diameter d=40 for three spring section figure(7-c) von-mises stresses of constsnt coil diameter d=50 for three spring section al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 145 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. in figure (8) we comparing the theoretical results with the results of the program with little differences . finally the circular section is the favorite for the spring design under the same condition of the square and rectangular spring section . figure(8-a) comparing between theoretical and practical stresses for circular section figure(8-b) comparing between theoretical and practical stresses for square section figure (8-a) comparing between theoretical and practical stresses for rectangular section al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 146 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 6. conclusion: 1from the result we notice that the stresses are rising by increasing the coil diameter (d) for the same spring section . 2-the lower stress is being in the circular spring section as compared with the square and rectangular spring section. 3there are an similarity between the analysis by the program result and the theoretical result. references 1. yildirim,v.,2002,expressions for predicting fundamental natural frequencies of non cylindrical helical spring ,pp 259-370 2.pomeranz,s.,2000,using a computer algebra system to teach the finite element method,inte,j.,engng,pp 362-368. 3. mohamed,t., & said,a.,& mohamed, h.,2008,a finite element for dynamic analysis of a cylindrical isotropic helical spring, transations of the asme vol.123 118-124. 4. azzaz, s.a. ,& kaoua, & dahmoun,d.,2004,a twin helical spring numerical modeling under tension loading, asme j eng ind, vol 95, pp 1139 – 1148. 5. budynas,& richard, g.,& charles, r.,& mischke, & joseph, e., shigley,2003, mechanical engineering design, mcgraw-hill professional. <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 26 effect of addition the conductive screws on the behavior of reinforced concrete beams and columns khamail abdul-mahdi mosheer department of civil engineering al-qadisiyah university / lecturer kh20072011@gmail.com received on 01 june 2016 accepted on 30 november 2016 abstract in the present paper, experimental investigations were used to study the effect of the addition conductive screws on the behavior of reinforced concrete columns and beams. screws with 25.4mm (1 inch) length were used. these screws were made of iron coated with zinc-aluminium alloy (called al-clad), which is resistant to corrosion and rust. the volume fractions of the conductive screws were 0%, 0.5%, 1%, and 1.5% by volume of concrete mix with water/cement ratio equal to 0.55. the results show that the use of the conductive screws enhanced the strength. the strength in tested beams was increased by 15.78%, 44.73%, and 76.31% for 0.5%, 1%, and 1.5% screws content respectively compared to the reference beam with no screws. the same trend was observed with the columns results, where the strength was increased by 12.44%, 26.79%, and 50.71% for 0.5%, 1%, and 1.5% screws content respectively compared to the reference column with no screws. key words: screws, reinforced concrete columns, reinforced concrete beams. على تصرف العتبات الخرسانیة المسلحة واالعمدة اضافة الصوامیل الموصلة تأثیر دراسة الخرسانیة المسلحة خمائل عبد المھدي مشیر مدرس/ كلیة الھندسة/قسم الھندسة المدنیة/جامعة القادسیة الخالصة الخرسانیة المسلحة واالعمدة الخرسانیة المسلحة. تصرف العتبات على الصوامیل الموصلة اضافة تأثیر دراسة ھو البحث ھذا من الھدف انج). -١ملم ( ٢٥.٤. تم استخدام صوامیل موصلة بطول من حجم الخلطة الخرسانیة). ,and 1% %1.5 ,%0.5 ,%0وبنسب مختلفة ( للتآكل والصدأ والتي تعطي القوة المقاومة (al-clad)المنیوم والمسماة -ھذه الصوامیل الموصلة مصنوعة من الحدید المطلي بسبیكة زنك ) والنسبة الحجمیة للصوامیل الموصلة التي اضیفت للخرسانة w/c=0.55والمرونة للصوامیل. نسبة الماء الى سمنت التي استخدمت كانت ( العتبات واالعمدة. من حجم الخلطة الخرسانیة). النتائج بینت ان وجود الصوامیل زاد من مقاومة تحمل and 1.5% ,%1 ,%0.5 ,%0كانت ( ,%0.5 ) عن العتب المرجعي الخالي من الصوامیل الموصلة وللنسب (%76.31 ,%44.73 ,%15.78حیث زاد تحمل العتبات بمقدار ( ) عن العمود %50.71 , %26.79,%12.44من حجم الخلطة الخرسانیة) على التوالي. كما زاد تحمل االعمدة بمقدار (,1.5%, 1% من حجم الخلطة الخرسانیة) على التوالي. ,%1.5, %1 ,%0.5 من الصوامیل وللنسب ( المرجعي الخالي الكلمات المفتاحیة: صوامیل الموصلة، العتبات الخرسانیة المسلحة، االعمدة الخرسانیة المسلحة. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 27 1. introduction. concrete is relatively a brittle material and has poor toughness. addition of randomly distributed fibres improves concrete structural characteristics such as, strength, ductility and flexural toughness etc., which depend upon fibre type, size, aspect ratio and volume fractions of the fibres used (singh et al. 2010). steel fibre is one of the most commonly used fibres. the effect of using steel fibres on the behavior of concrete has been studied by many researchers. (craig et al. 1984) reported that adding steel fibers to a reinforced concrete column improved its compressive strength, shear strength, and ductility. the study carried out by (oh 1992) indicates that ductility and ultimate resistance of reinforced concrete beams are remarkably enhanced due to the addition of steel fibres. (casanova et al. 1997) shown that steel fibers can be used to significantly reduce the amount of transverse shear reinforcement in beams while maintaining the required shear resistance. (cohen 2012) show that if steel fibres added in sufficient quantity can be used to replace traditional shear reinforcement and promote flexural failure and ductility . ( namdar et al. 2013) indicated that steel fiber improves flexural strength of beams and controlled crack morphology. (aoude et al. 2014) show that the addition of steel fibres in concrete columns enhances confinement and cover spalling. the results obtained by (mosheer 2015) showed that the addition of conductive screws to plain concrete led to enhancement mechanical properties of concrete. in this study, conductive screws made from iron coated with zinc-aluminium alloy (called al-clad), which is resistant to corrosion and rust, were used as a short fibre to reinforce conventional concrete. the screws were used in different volume fractions. experimental investigations were conducted to study the effect of addition conductive screws on columns and beams. 2. experimental program experimental program was mainly designed to examine the effect of addition conductive screws with different volumetric ratios on the behavior of reinforced concrete beams and columns. 2.1 specimen details the experimental work involved testing of four beams and four columns. the dimensions of beams and columns are 1200 × 150 × 150 mm. geometry and reinforcement detail for beams and column are shown in fig1. 2.2 materials properties 2.2.1 concrete sulphate-resistant portland cement (type v) was used, coarse aggregate have a (5-19) mm size crushed gravel and the fine aggregate was natural river sand, zone 2 according to iqs:45 1984 with 2.85 fineness modulus. 2.2.2 steel reinforcement arrangement of steel bar used in tested beams and columns are indicted in fig1. sample of steel bars was tested by tensile testing machine to product some properties of them, results of test were listed in table 1. 2.2.3 screws the conductive screws were used throughout the experimental program, made from iron coated with zinc-aluminium alloy, which is resistant to corrosion and rust. the screws were used with length 25.4 mm (1 inch) as shown in fig 2. some properties of the screws are listed in table 2. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 28 2.3 mix proportions volumetric mixing ratio of (1:2:4) was used, with water/cement ratio (w/c) = 0.55. cylinders and prisms for each mix were cast and stored with each beam and column. average results of cylinder strength !c and modulus of rupture f r are given in table 3. the screws were added in volume fractions of 0%, 0.5%, 1%, and 1.5% by volume of the total mix for the beams (b0, b1, b2,and b3) respectively, and for columns (c0, c1, c2,and c3) respectively as indicted in table 4. the beam and column with no screws were considered as a reference sample. after a 28 day of curing, a tests were conducted for the reinforced concrete members. 3. testing procedure 3.1 reinforced concrete beams test all the tested beams were simply supported under one point load at mid span which incrementally loaded up to maximum load capacity by means of a hydraulic jack with maximum capacity of 200 kn. dial–gage placed vertically at mid span of beams to measure the deflection at each increment of the load. 3.2 reinforced concrete columns test all columns were tested for concentric axial loads by an universal testing machine with capacity of (200) ton. the ends supports of all tested columns simulate the simply support conditions with no sideways movement (braced columns) because the top and bottom ends of the columns are not capable to move laterally. to ensure a uniform distribution of the axial compressive load, a square steel bearing plate with dimensions of (200×200×5) mm (width ×length× thickness) was fixed at the top end of each column during the test. the load was applied through a bearing plate in small increments up to failure. a dial-gage placed vertically at the top face of column to recorded the axial deformation, while the lateral deflection was measured using dial-gages placed horizontally at the mid height of column in each side. after each increment, the load was kept constant until the required measurements were recorded. 4. discussion of the results 4.1 reinforced concrete beams from the test results shown in table 5 and fig 3 and 5, it can be seen that ultimate axial load increases with increasing the screws content. the ultimate axial load increased by 15.78%, 44.73%, and 76.31% for b1, b2, and b3 respectively from reference beam with no screws b0. the increase in ultimate axial load appears more clearly with screws contents of 1.5% for beam b3 compared to the reference beam b0. from fig 5 it can be observed that cracks width decreases and number of cracks increase with increasing the volume fraction of the screws compared with the reference beam b0 (0.0% added ratio). this is due to the fact that the load path is intercepted by the conductive screws, which leads to a change in its direction. 4.2 reinforced concrete columns the reinforced concrete columns test results are illustrated in table 5 and fig 6 to 8. the ultimate axial load increased by 12.44%, 26.79%, and 50.71% for c1, c2, and c3 respectively from reference beam with no screws c0. fig 9 show the reinforced concrete column specimens shapes after failure. as can be seen from this fig, all tested columns have experienced similar failure pattern represented by concrete crushing at the top of the column followed by generating of cracks and splitting of the concrete cover. 5. conclusions from the experimental results, the following conclusions can be stated: al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 29 1. the use of conductive screws works to increasing the strength capacity for reinforced concrete columns and beams. this is due to the ability of screws to control and redistribute the stresses after cracking. 2. the strength of beams and columns increased with increasing the screws content. 3. the cracks width in reinforced concrete beams decreases with increasing the screws content, instead, there was an increase in the number of cracks. references aoude, h., hosinieh, m., cook, w., and mitchell, d. (2014), "behavior of rectangular columns constructed with scc and steel fibers." journal of structural engineering, 10.1061/(asce)st.1943-541x.0001165 , 04014191. casanova, p., rossi, p., and schaller, i. (1997), “can steel fibers replace transverse reinforcements in reinforced concrete beams?” aci materials journal, v. 94, no. 5, sept.-oct., pp. 341-354. cohen, m. (2012) “structural behaviour of self consolidating steel fiber reinforced concrete beams,” m.s. thesis, dept. civil. eng., ottawa. univ., ottawa. craig, r. j., dunya,s., riaz, j., and shirazi ,h. (1984), “torsional behavior of reinforced fibrous concrete columns” fiber reinforced concrete-international symposium. sp-81. american concrete institute. detroit. sp-81, pp.17-49. mosheer, k. a., (2015) “addition of conductive screws to improve the mechanical properties of concrete” al-qadisiyah journal for engineering sciences, vol. 8, no. 2, pp.211-224. namdar, a., zakaria, i. b., hazeli, a. b., azimi, s. j., bin, a. s., and razak, a., (2013), “an experimental study on flexural strength enhancement of concrete by means of small steel fibers” frattura ed integrità strutturale,v. 26, doi: 10.3221/igf-esis.26.03., pp. 22-30. singh, s.p., singh, a.p., and bajaj, v. (2010), “strength and flexural toughness of concrete reinforced with steel – polypropylene hybrid fibres” asian journal of civil engineering (building and housing) vol. 11, no. 4, pp. 495-507. oh, b.h. (1992), “flexural analysis of reinforced concrete beams containing steel fibres” journal of structural engineering, asce, vol. 118, no. 10, pp. 2821–2836. material type fy mpa fu mpa ø 12 bar 447 731 ø 10 bar 452 729 table 1: test results of steel bars (mpa) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 30 material type average diameter (mm) head diameter (mm) length mm density kg/m 3 modulus of elasticity gpa screw 3 6.5 25.4 7500 200 fibre content % !" mpa # mpa 7 days 28 days 0.0 14.91 19.4 2.75 0.5 15.32 21.37 2.84 1.0 15.72 22.41 2.90 1.5 17.69 23.82 2.94 member type member no. screws content % !" mpa beam b0 0.0 19.4 b1 0.5 21.37 b2 1.0 22.41 b3 1.5 22.92 column c0 0.0 19.4 c1 0.5 21.37 c2 1.0 22.41 c3 1.5 23.82 table 3 : test results of concrete (mixing ratio=1:2:4) table 2 : properties of conductive screws table 4: details of reinforced concrete beams and columns al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 31 member type member no. screws content % ! mpa ultimate load pu (kn) increasing rate in ultimate load % beam b0 0.0 19.4 38 - b1 0.5 21.37 44 15.78 b2 1.0 22.41 55 44.73 b3 1.5 22.92 67 76.31 column c0 0.0 19.4 418 c1 0.5 21.37 470 12.44 c2 1.0 22.41 530 26.79 c3 1.5 22.92 630 50.71 table 5: test result of beams and columns 31 figure 1: geometry and reinforcement detail for (a): beams, (b): columns al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 32 figure 2: screws used figure 3: load-deflection curve for beams b0(0%) ,b1 (0.5%), b2 (1%), and b3 (1.5%) 32 figure 4: the relationship between ultimate load in beams and the screws content al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 33 ` b0 (0.0%) b1 (0.5%) b2 (1.0%) b3 (1.5%) figure 5: failure mode of reinforced concrete tested beams al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 34 0.0 0.5 1.0 1.5 screw addition % 400 450 500 550 600 650 u lt im a te a x ia l l o a d ( k n ) 0.0 1.0 2.0 3.0 4.0 5.0 6.0 axial deflection (mm) 0 100 200 300 400 500 600 700 a x ia l l o a d ( k n ) c0 (0.0%) c1 (0.5%) c2 (1.0%) c3 (1.5%) figure 6: loadlateral deflection curve for columns c0 , c1, c2, and c3 figure 7: load-axial deflection curve for columns c0 ,c1, c2, and c3 34 figure 8: the relationship between ultimate load in columns and the screws content al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 35 c0 (0.0%) c1 (0.5%) c2 (1.0%) c3 (1.5%) figure 9: failure modes of reinforced concrete columns ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٠ تأثير إضافة دقائق األلومينا على الخواص الميكانيكية للمادة المركبة ذات األساس من البولي أستر غير المشبع المقواة بألياف الزجاج غير المستمرة المهندسة أسيل محمود عبد اهللا المهندس أحمد مظفر هاشم المهندس عمار جبار بدر مدرس مساعد مدرس مساعدمدرس كلية الهندسة– جامعة القادسية كلية الهندسة– جامعة القادسية هندسة المواد-الجامعة التكنولوجية :الخالصة ، (e-glass)جاجية مقطعة نوع مقواة بألياف ز) بولي أستر(تم تصنيع مادة مركبة ذات أساس بوليمري ونماذج أخرى من المادة ذات األساس البوليمري مقواة بألياف الزجاج ودقائق األلومينا معاً وبثالث كسور إجراء فحوصات ميكانيكية للعينات مثل فحص الصدمة والصالدة وتم. (wt % 7 ,5 ,3) وزنية مختلفة إن الطاقة الممتصة . كانيكية تتحسن مع زيادة الكسر الوزنيواالنحناء ، ومن النتائج تبين أن الخواص المي مقارنة مع العينات المقواة بألياف للكسر أعطت أفضل النتائج للعينات المقواة بألياف الزجاج ودقائق األلومينا .الزجاج فقط وبنفس الكسور الوزنية .غير المشبع ، اختبار الصدمة ، اختبار الصالدة ألياف الزجاج ، دقائق األلومينا ، البولي أستر :الكلمات االيضاحية effect of alumina particles on the mechanical properties of discontinuous glass fiber reinforced unsaturated polyester composites aseel mahmood abdullah ahmed mudhaffer hashim amar jabar bader university of technology, university of qadissiya, university of qadissiya, department of engineering collage of engineering, collage of engineering materials department of department of mechanical engineering mechanical engineering abstract the polyester matrix composites reinforced with short glass fiber and reinforced with glass fiber and al2o3 particles with different weight fractions (3, 5, and 7 wt% al2o3) were prepared and then the mechanical testing (bending, impact, and hardness) were measured. the results showed the mechanical properties improve with increasing weight fraction. the impact energy of hybrid ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧١ composite is better than compared with the composite reinforced with glass fiber alone at same weight fractions. مقدمة مثل المادة (polymer matrix composites, pmcs) المادة المركبة ذات األساس البوليمري glass fiber)البوليمرية المقواة بأليــــــــــــــاف الزجـــــــــاج reinforced polymer composites, gfrp) ، تستخدم بشكل واسع في التطبيقات الهندسية المتنوعة أن المادة المركبة ذات األساس البوليمري تعتبر سهلة التصنيع : ذلك إلى المميزات التاليةويعود سبب وتكون كثافتها واطئة فهي تمتلك نسبة . والتحتاج إلى أدوات ذات كلفة عالية ، ولذلك تكون كلفتها منخفضة ا في التطبيقات مما يجعل استخدامها واسع (strength to weight ratio)متانـــة إلى الوزن عالية ونظرا لالستخدامات الواسعة للمادة المركبة ذات األساس . [urmimala maitria, etcl, 2009]الفضائية أو مواد تقوية filler هذه المواد المضافة أمـا أن تكون حشوات . البوليمري ، فانها تحتاج إلى إضافة مواد reinforcementالحشوات . على الخواص الميكانيكية للمنتج النهائي باإلعتماد على تأثير المادة المضافة تضاف بصورة رئيسية لتقليل الكلفة للمنتج النهائي ، بينما التقوية تضــاف لكي تحسن الخواص الميكانيكية [clarles a. harper, etcl, 2006] . ومن أمثلة مواد التقوية المضافة هي كاربونات الكالسيومcaco3 ، التي تعمل على تحسين خواصها الميكانيكية sic، كاربيد السليكون al2o3األلومينا ,donald r. askeland, etcl]كالصـــــــالدة والبلى والزحف وكذلك تحسين الخواص الحرارية إن المادة المركبة ذات األساس البوليمري المقواة بالمواد المذكورة أعاله تستخدم في تطبيقات عديدة . [2003 ,suryasarathi bose, etcl]ــة السيـــارات واألدوات الكهربائيــة واأللكترونيـة مثل صناعـ بدراسة الخواص [qi zhang, etcl, 2004] 2004 وزمالءه في عام qi zhangقام الباحث . [2004 حيث استخدم الباحث وزمالءه مساحيق . الميكانيكية لمادة مركبة ذات أساس بوليمري مقواة بالمساحيق لفة هي هيدروكسيد المغنسيوم وهيدروكسيد األلمنيوم وبأحجام حبيبية مختلفة لتقوية المطاط ، ووجدوا أن مخت قام الباحث 2006في عام . تتحسن عند تقليل الحجم الحبيبي) مقاومة الشد واالستطالة(الخواص الميكانيكية edcleide m. araújo وزمالءه[edcleide m. araújo, etcl, 2006]راسة الخواص الميكانيكية بد ,30 ,20)لمادة مركبة ذات أساس من البولي أستر غير المشبع المقواة بألياف الزجاج وبنسب تقويـــة 40, 50, 60 wt %) ومقارنتها بتلك المقواة بألياف الزجاج التالفة (fiber glass wastes) وبنفس نسب البولي أستر بالياف الزجاج التالفة ، خاصة بعد أعطت للمادة وقد توصل الباحثون أنه باالمكان تقوية. التقوية osman asi [osman asi, 2008] قام الباحث 2008وفي العام . البوليمرية مقاومة صدمة عالية على الخواص الميكانيكية للمادة المركبة ذات wt % 10بدراسة تأثير إضـــسافة دقائق األلومينا بنسبة وقد بين الباحث أن مقاومة االنحناء ومعامل االنحناء تزدادان . ي المقواة بألياف الزجاجاألساس من االيبوكس على التوالي عند إضافة دقائق األلومينا مقارنة بالمادة المركبة غير المقواة بدقائق % 78 و %33بنسبة ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٢ ,urmimala maitria, etcl] وزمالءه urmimala maitra ، قام الباحث 2009 أما في عام . األلومينا diamondبدراسة الخواص الميكانيكية لمادة مركبة ذات أساس بوليمري مقواة بمسحوق الماس [2009 powder حيث استخدموا البولي فينيل الكحول ، polyvinyl alcohol كمادة أسـاس ومسحوق الماس ومعامل المرونة للمادة وقد وجد الباحثون أن الصالدة .(wt % 0.6)كمادة تقوية بكسر وزني مقدره . البوليمرية تتحسن بشكل ملحوظ عند التقوية بمسحوق الماس إن البحث الحالي يهدف إلى دراسة تأثير إضافة األلومينا على سلوك المادة المركبة ذات األساس من ودراسة (wt % 7 ,5 ,3)البولي أستر غير المشبع المقوى بألياف الزجاج المقطع وبكسور وزنية مختلفة سلوكها في االختبارات الميكانيكية مثل اختبار االنحناء واختبار الصدمة ، ومقارنة سلوكها بالمادة المركبة ذات األساس من البولي أستر غير المشبع المقوى بألياف الزجاج بشكل منفرد وبنفس الكسور الوزنية .المذكورة أعاله الجزء العملي السعودية كمادة أساس ، (sir) أستر غير المشبع والمصنع من قبل شركة استخدام راتنج البولي تم والذي يكون على شكل سائل لزج شفاف عند درجة حرارة الغرفـــة وهو أحد أنـــــــواع ، يتحول من الحالة السائلة إلى الحالة (thermosetting polymers)البوليمرات المتصلدة بالحرارة والمصلد . إليه والمصنع من قبل نفس الشركة المذكورة أعاله(hardener)مصلد الصلبة وذلك بإضافة ال والذي يكون على (methyl ethyl keton peroxide, mekp)عبارة عن بيروكسيد مثيل أثيل كيتون من (grams 10) لكل (grams 2)شكل سائل شفاف يضاف إلى راتنج البولي أستر غير المشبع بنسبة يبين خصائص مادة البولي أستر غير المشبعة (1)الجدول رقم و. جة حرارة الغرفةالراتنج عند در . المستخدمة في البحث حسب مواصفات الشركة المنتجة : تم استخدام نوعين من مواد التقوية هي األلياف ) مقطعة(على شكل ألياف غير مستمرة (e-glass) استخدمت في هذا البحث ألياف الزجاج من نوع . يبين الخصائص الميكانيكية والفزياوية أللياف الزجاج(2)الجدول رقم و.(mm 10)وبطول ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٣ الدقائق وقد تم تحديد الحجم الحبيبي . (53µm-50 ) تم استخدام األلومينا بشكل مسحوق ناعم ذو حجم حبيبي . باستخدام المناخل الكهربائية وتكون الجوانب متحركة وترتبط بالقاعدة بواسطة . ادة الخشب وتم تصنيع قالب ذو قاعدة وجوانب من م يوضح القالب الخشبي الذي تم (1)الشكل رقم و (mm 5×300×300)وأبعاد القالب المستخدم . المثبتات . تصنيعه والمستخدم في تحضير عينات البحث حيث تم الحصول . حث في تصنيع عينات الب(hand-lay-up moulding) تم استخدام الطريقة اليدوية % 7 ,5 ,3)على عينات البولي أستر غير المشبع المقوى بألياف الزجاج المقطعة بثالث كسور وزنية هي wt) وتم تصنيعهــــا بمزج مادة البولي أستر غير المشبع مع المصلد بنسبة ، (2 grams) 100) لكل grams)دقائق (10-8) المقطعة ويستمر المزج لمدة وتتم عملية المزج بإضافة ألياف الزجاج. من الراتنج بعدها يصب المزج في القالب الخشبي على شكل سيل من إحدى جوانب القالب ، . إلى أن يتجانس الخليط أما عينات البولي أستر المقواة بألياف الزجاج المقطعة ودقائق . بحيث يسيل بصورة منتظمة ومستمرة كورة أعاله ، فقد تم تصنيعها بمزج دقائق األلومينا مع الراتنج والمصلد األلومينا وبنفس الكسور الوزنية المذ دقائق ، ومن ثم يصب المزيج في (10)وثم الخلط إلى أن يتجانس المزيج لمدة . مع األلياف في نفس الوقت .القالب الخشبي الفحوصات : من الفحوصات التي أجريت على النماذج المحضرة هي كما يلي ة فحص الصدم حيث تم استخدام النماذج بأبعاد (charpy impact test) تم استعمال جهاز شاربي لفحص الصدمة . (iso-179) وبدون حز على وفق النظـــــــام العالمي (mm 4×10×80)قياسية فحص اإلنحناء span to ) وبنسبة طول إلى سمك (mm 4.8×13×191) تم تحضير عينات االنحناء بأبعـاد قياسية depth ratio ) على وفق المواصفــــة األمريكيـــــة 1:32 مقدارها ( astm d-790 ). ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٤ فحص الصالدة دائرية المقطع بقطروالعينة المستعملة بهذه الطريقة (shore d) لغرض قياس الصالدة تم اتباع طريقة (40 mm) وسمك (4 mm)حسب المواصفة (din-53505) . والمناقشةالنتائج نتائج ومناقشة اختباري الصدمة والصالدة يوضحان تأثير تغيير الكسر الوزني على الطاقة الممتصة الالزمة للكسر للمادة (2,3)الشكلين رقم البوليمرية المقواة بألياف الزجاج ودقائق األلومينا ، ويالحظ من المخطط أن الطاقة الممتصة الالزمة للكسر الكسر الوزني بعالقة الخطية وذلك نتيجة عمل مواد التقوية كحاجز أمام الشق النامي خالل تزداد بزيادة المادة المتراكبة وخصوصاً دقائق األلومينا تعمل على اعاقة نمو الشق وهذا سوف يؤدي إلى تغير الشق لى زيادة المساحة إن هذا التغيير في شكل الشق واتجاهه أدت إ. واتجاهه بتحوله إلى مجموعة شقوق ثانوية السطحية للكسر والطاقة المصروفة وهذه كلها عوامل أدت إلى زيادة مقاومة المادة وهذه الحالة تحصل بشكل . أفضل عندما يكون هنالك ربط بين مادة األساس والدقائق كما هو الحال في دقائق األلومينا والمادة األساس بآلية مختلفة تعتمد على مالقاة الشق للسطوح الضعيفة وضياع أما في حالة الربط األقل قوة فأن التقوية تتم باالمكان جعل الراتنجات أكثر مقاومة ضد نمو . )٢٠٠٧, سعد ميخائيل حنا(وتحرر جزء من طاقته عندها ). ١٩٩٤, قحطان الخزرجي. د(الشق بإضــافات جسيمات من مواد معينة للمواد المضافة في الصالدة حيث نالحظ أن الصالدة تزداد تأثير الكسر الوزني (4,5)يوضح الشكلين وزمالءه edcleide m. araújoبإضافة ألياف الزجاج منفردة بشكل طفيف وهذا يتفق مع رأي الباحث [edcleide m. araújo, etcl, 2006] أن ألياف الزجاج تؤثر على صالدة المادة المركبة ذات األساس بألياف كما نالحظ أن المادة المركبة ذات األساس البوليمري المقواة . الزجاجالبوليمري المقواة بألياف الزجاج مع دقائق األلومينا تزداد الصالدة مع زيادة الكسر الوزني ، ومن مفهوم الصالدة يمكن عدها مقياساً ترفع من صالدة للتشوه اللدن الذي يمكن أن تعاني فيه المادة تحت تأثير خارجي وبذلك فان اضافة الدقائق إن تقوية البوليمرات ببعض الجسيمات يؤدي إلى زيادة صالدة . المادة نتيجة لزيادة مقاومتها للتشوه اللدن إن لنوع الدقائق المضافة إلى البولي أستر ). ١٩٩٤, قحطان الخزرجي. د(السطح والمقاومة ضد االختراق ولما كانت صالدة . تماداً على صالدة الدقائق المضافةتأثير كبير على صالدة المادة المتراكبة الناتجة واع 34.3 ، 33.8 ، 33.5دقائق األلومينا عالية نالحظ أن العينات المقواة بألياف الزجاج ودقائق االلومينا كانت وهذا يعود إلى أن األلومينا هي مــادة سيراميكية تمتاز بالصـــالدة (wt % 7 ,5 ,3) الوزنية للكسور .[r. a. higgen, 2006]لية العـــــا ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٥ نتائج ومناقشة اختبار االنحناء . تأثير الحمل المسلط على معدل االنحراف ولكسور وزنية مختلفة وبعالقات طردية (6.7)يمثل الشكالن ومن خالل الشكلين يالحظ أنه مع زيادة الكسر الوزني للمواد المضافة فانه يؤدي إلى تقليل االنحراف عند %7 ، %5 ، %3فبالنسبة للعينات المقواة بألياف الزجاج فقط وبكسور وزنية . لليف إلى حمل معينتعرض ا عند نفس الحمل أعطت العينات المقواة 222n غرام فان العينات أعطت انحرافاً مقداره 1200وعند حمل 77ة أعطت انحرافاً مقداره بألياف الزجاج مع دقائق األلومينا أي المتراكبات الهجينة وبنفس الكسور الوزني n . سواء المقواة بألياف الزجاج فقط أو بألياف الزجاج مع دقائق %7بينما في العينات ذات الكسر الوزني 222nاللومينا نالحظ زيادة االنحراف عند نفس الحمل فمثالً التقوية بألياف الزجاج مقدار االنحراف من هذه النتائج تبين لنا أن المادة . n 146لومينا االنحراف وبالنسبة للتقوية بألياف الزجاج ودقائق األ المتراكبة المقواة بألياف الزجاج ودقائق األلومينا كان فيها قوة الترابط بين التقوية والمادة األساس أعلى من سمح وهذا يعود إلى أن اختبار االنحناء هو اجهاد بطيء ي. قوة الترابط بين ألياف الزجاج والمادة األساس بتفاعل الشقوق مع الدقائق كما يختلف عن اختبار الشد بطبيعة القوة المؤثرة في العينة فان القوى المؤثرة في كما تتأثر مقاومة االنحناء بشكل كبير بقوة الربط بين مادة األساس . اختبار االنحناء هي قوى شد وضغط معاً . [l. holiday, 1966]ومادة التقوية االستنتاجات افة ألياف الزجاج بشكل منفرد وألياف الزجاج مع دقائق األلومينا إلى المادة البوليمرية أدى إلى إض -١ . تحسين الخواص الميكانيكية كالصدمة والصالدة واالنحناء الصالدة زادت مع زيادة الكسر الوزني للمادة البوليمرية المقواة بألياف الزجاج ودقائق األلومينا للكسور -٢ . وأعطت نتائج أفضل من ألياف الزجاج بشكل منفرد ولنفس الكسور الوزنية (wt % 7 ,5 ,3)الوزنية الطاقة الممتصة للكسر أعطت أفضل نتائج للعينات المقواة بألياف الزجاج ودقائق األلومينا بكسور وزنية -٣ (3, 5, 7 % wt)مقارنةً مع العينات المقواة بألياف الزجاج فقط ولنفس الكسور الوزنية . المصادر 4clarles a. harper, “hand book of plastic thecnologies”, mc graw hilll companies, 2006. 5donald r. askeland and pradeep p. phule, “the science and enginerring of materials”, 4th edition, plenum press, new york, 2003. 6edcleide m. araújo, kasselyne d. araújo, osanildo d. pereira, pollyana c. ribeiro and tomás j. a. de melo, “fiberglass wastes/polyester resin composites: mechanical properties and water sorption”, polimeros ciencia e technologia, vol. 16, no. 4, pp 332-335, 2006. 7l. holiday, “composite material”, elsevier publish, 1966. 8osman asi, “mechanical properties of glass-fiber reinforced epoxy composites filled with al2o3 particles ”, journal of reinforced plastics and composites, doi:10.1177/0731684408093975, 2008. ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٦ 9qi zhang, ming tian, youping wu, guilin and liqun zhang, “effect of particle size on the properties of mo(oh)2-filled rubber composites”, journal of applied science, vol. 94, pp 23341-2346, 2004. 10 r. a. higgen, “materials for engineers and technicians”, 4th edition, newnes publications, 2006. 11suryasarathi bose and p. a. mahanwar, “effect of particle size of filler on properties of nylon-6”, journal of mineral and materials characrization and engineering, vol. 3, no. 1, pp 23-31, 2004. 12urmimala maitria, k. eswas prasad, u. ramamurty and c. n. r. rao, “mechanical properties of nano diamond-reinforced polymer matrix composites”, solid state communication journal, elsevier ltd., 2009. دراسة الخصائص الميكانيكية والتوصيلية الحرارية لمادة متراكبة ذات أساس بوليمري مقواة "سعد ميخائيل حنا، -١٣ .٢٠٠٧الجامعة التكنولوجية ، -، أطروحة ماجستير ، قسم هندسة المواد"ئق األلمنيوم واوكسيد األلمنيومبدقا .١٩٩٤كلية الهندسة ، -، جامعة بابل"مبادئ هندسة المواد الالمعدنية"قحطان خلف الخزرجي، . د. أ -١٤ ولي أستر غير المشبعة يبين الخصائص الميكانيكية والفيزياوية والحرارية لمادة الب(1)الجدول رقم .المستخدمة في البحث حسب مواصفات الشركة المنتجة percent elongation el % tensile strength mpa coefficient of thermal expansion 10-6 specific heat j/kg. k thermal conductivity w/m density gm/cm3 <2.6 41.4-89.7 100-180 710-920 0.17 1.2 (e-glass). يبين الخصائص الميكانيكية والفيزياوية أللياف الزجاج نوع (2)الجدول رقم density gm/cm3 tensile modulus gpa tensile strength mpa 2.5 69 2400 ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٧ 5 mm 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 weight fraction (%) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 im pa ct e ne rg y (j ) .يوضح القالب الخشبي الذي تم تصنيعه والمستخدم في تحضير عينات البحث(1)الشكل رقم يبين يوضح العالقة بين مقاومة الصدمة والكسر الوزني أللياف الزجاج للمادة المركبة ذات األساس من (2)شكل رقم ال .البولي أستر غير المشبع المقواة بألياف الزجاج ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٨ 2.0 4.0 6.0 8.0 10.0 weight fraction (%) 20.0 25.0 30.0 35.0 40.0 h ar dn es s (h v ) 0.0 2.0 4.0 6.0 8.0 10.0 weight fraction (%) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 im pa ct e ne rg y (j ) كبة ذات األساس يبين يوضح العالقة بين مقاومة الصدمة والكسر الوزني لدقائق األلومينا للمادة المر(3)الشكل رقم .من البولي أستر غير المشبع المقواة بألياف الزجاج يبين يوضح العالقة بين الصالدة والكسر الوزني أللياف الزجاج للمادة المركبة ذات األساس من (4)الشكل رقم .البولي أستر غير المشبع المقواة بألياف الزجاج ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٧٩ 2.0 4.0 6.0 8.0 10.0 weight fraction (%) 20.0 25.0 30.0 35.0 40.0 h ar dn es s (h v ) 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 deflection (mm) 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 110.00 120.00 130.00 140.00 150.00 160.00 170.00 180.00 190.00 200.00 210.00 220.00 230.00 lo ad (n ) لعالقة بين الصالدة والكسر الوزني لدقائق األلومينا للمادة المركبة ذات األساس من يبين يوضح ا(5)الشكل رقم .البولي أستر غير المشبع المقواة بألياف الزجاج يبين يوضح العالقة بين الحمل واالنحراف للمادة المركبة ذات األساس من البولي أستر غير المشبع (6)الشكل رقم . الزجاجالمقواة بألياف ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٠ 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 deflection (mm) 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 110.00 120.00 130.00 140.00 150.00 lo ad (n ) يبين يوضح العالقة بين الحمل واالنحراف للمادة المركبة ذات األساس من البولي أستر غير المشبع المقواة (7)لشكل رقم بألياف الزجاج ودقائق األلومينا <4d6963726f736f667420576f7264202d20e3e4d6cf20c7cde3cf20c7e1d4d1da> al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 95 effect of single or multi rotating horizontal cylinders on the mixed convection heat transfer inside a triangular enclosure dr. ahmed k. m. alshara mechanical engineering department college of engineering basra university abstract this study investigates the effect of rotating horizontal single or multi cylinders on mixed convection heat transfer in an equilateral triangular enclosure filled with air. the governing equations for the steady, laminar, two dimensional, incompressible flows with boussinseq approximation and constant fluid properties are solved numerically using the finite element method with flexpde soft package. three cases are performed: single rotating cylinder, three rotating cylinders at the same direction and three rotating cylinders at different directions. the main parameters are: rayleigh number ( 52 1010 −=ra ), prandtl number ( 7.0pr = ), the dimensionless angular velocity (ω=01000) (for both directions clockwise cw and counter clockwise ccw) and dimensionless radius of rotating cylinder (r=0.1-0.25). it was found that the average nusselt number for the single or multi rotating cylinder is increased with increasing ra, r and ω for all cases. also the average nusselt number of single rotating cylinder is greater than the multi rotating cylinders for the same ratio of the solid cylinder or cylinders volume to total enclosure volume. the results are compared with other authors in the literature and a good agreement was seen. keywords: mixed convection, rotating cylinder, triangular enclosures, finite elements method متعددة أومنفردة دوارة أفقية اتاسطوان تأثير فجوة مثلثةفي الحمل المختلط انتقال حرارةعلى حمد كاظم محمد الشرعأ. د البصرةجامعة -كلية الھندسة -قسم الھندسة الميكانيكية موجزال حرارة بالحمل المختلط فيعلى انتقال ال فردة أو متعددةم دوارة أفقية اتبحث تأثير اسطوانتهذه الدراسة غير ،األبعاد ثنائي ،طباقي، المعادالت الحاكمة لجريان مستقر. مثلث متساوي اإلضالع مملوء بالهواء مغلق حيز معحلت عدديا باستخدام طريقة العناصر المحددة ۥ المائع و ثبوت خواص boussinseq انضغاطي مع تقارب ثالث اسطوانات دوارة بنفس االتجاه و ، فردةاسطوانة دوارة م: ث حاالت أنجزتثال .flexpde الحقيبة البرمجية 52(يلي ارقم ر : األساسية هي عواملال. مختلفة اسطوانات دوارة باتجاهات ثثال 1010 −=ra( ، رقم براندل al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 96 ( 7.0pr = وعكس cwعقرب الساعة هتجااب(ولكال االتجاهين (ω=0-1000) بعدية اللالسرعة الزاوية أ، ( رقم نسلت معدل وجد بان. (r=0.1-0.25)بعدي اللارة أو نصف قطر األسطوانة الدو ccw)عقرب الساعة رقم نسلت معدل كذلك. و لكل الحاالت ωو r, ra يزداد مع زيادة المتعددة أوفردة الم الدوارة لألسطوانة االسطوانات الصلبة أو لالسطوانة الدوارة المفردة اكبر من االسطوانات الدوارة الثالثة لنفس نسبة حجم األسطوانة .تطابق جيد بينتالنتائج قورنت مع نتائج باحثين آخرين في األدبيات و .إلى الحجم الكلي للحيز المغلق nomenclture b base of triangular enclosure m e non-dimensional radius of the centers circle of three cylinders, e/h g acceleration due to gravity m/s2 h height of equilateral triangular enclosure m k thermal conductivity w/m2.k nuav average nusselt number p dimensionless pressure, (p+ρcgy)h 2/ρα2 pr prandtl number, υ/ α r dimensionless radius of the rotating cylinder, r/h ra rayleigh number , gβk(th-tc) h 3/υα t temperature of the fluid in the enclosure k u,v non-dimensional velocity components , uh/α , vh/ α x, y non-dimensional coordinates, x=x/h, y=y/h greek symbols α thermal diffusivity of fluid m2/s β thermal expansion coefficient k-1 θ dimensionless temperature, θ=(t-tc)/( th-tc ) υ kinematics viscosity m2/s ρ density kg/m3 ω angular rotational velocity of solid cylinder rad/s ω dimensionless angular rotational velocity, ω h2/α subscripts av average c cold h hot o center introduction mixed convection (forced and natural convection) in an enclosure is found in many industrial and environmental applications such as electronic systems, solar energy systems, heat sinks, saving of materials and cooling equipments, etc. to improve both conductive and convective heat transfer and heat exchange with fluids, the rotating solid bodies (e.g. rotating solid cylinder) are used which represent one of methods to produce mixed convection in the enclosures. therefore a method of employing rotating circular cylinders in the enclosures is proposed to enhance the minute natural convection heat transfer of the enclosures. these configurations are important with several applications in engineering, science and environmental analysis. heat exchangers, cylindrical cooling devices in plastics and glass industries, grain storage, food and chemical processing and furnaces and drying al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 97 technologies are just some these applications. there are many geometric configurations of enclosures filled with convective fluids such as rectangular, triangular, elliptical and circular enclosures. (shu et al., 2001) studied numerically the natural convective heat transfer in a horizontal eccentric annulus between a square outer cylinder and a heated circular inner cylinder using the differential quadrature (dq) method. they analyzed the natural convection systematically for 510×3=ra and aspect ratio equal to 2.6 including the effects of outer cylinder location on average nusselt number, flow and thermal fields. (kim et al., 2008) carried out numerical calculations for natural convection induced by a temperature difference between a cold outer square enclosure and a hot inner circular cylinder. they investigated the effect of the inner cylinder location on the heat transfer and fluid flow for the range of rayleigh numbers 63 1010 << ra . also, they found that the presence of the secondary and tertiary vortices near the upper surfaces of the inner cylinder according to the variation of the inner cylinder position and rayleigh number has a large influence on the distribution of the local and surface-averaged nusselt numbers. (rahman et al., 2009) analyzed the mixed convection in rectangular cavity with a heat conducting horizontal circular cylinder. they developed mathematical model to solve continuity, momentum and energy equations employing galerkin weighted residual finite element method. the results show that the cavity orientation and the cylinder diameter have a great influence on the streamlines and isotherms distribution. (yu et al., 2010) performed a numerical study of laminar convection from a horizontal triangular cylinder to its concentric cylindrical enclosure to investigate the prandtl number effect on flow and heat transfer characteristics. the finite volume approach was used to solve the governing equations, in which buoyancy is modeled via the boussinesq approximation. they found that the flow and heat transfer characteristics for a low prandtl number fluid (pr=0.03) are unique and they are almost independent of prandtl number when pr≥0.7. a multi circular and square rods in cavities with laminar natural convection was studied by (braga and lemos, 2005). governing equation (momentum and energy equations that resemble a conjugate heat transfer problem for in both the solid and the void space) were solved using finite volume method. they found that the average nusselt number for cylindrical rods is slightly lower than those for square rods considering the same modified rayleigh number. (ashjaee et al., 2008) studied the convective heat transfer from the inner cylinder of an annular gap of eccentric cylinders with air enclosed. the inner and the outer cylinder have low and high constant temperature, respectively. the rotational reynolds number considered based on the inner and outer cylinders diameters is in the range 0-1200. they observed when the cylinders are rotated a decrease in the heat transfer from the inner cylinder in three different phases; a slight decrease, a dramatic decrease and becoming constant, while the rotation of the outer cylinder increases the heat transfer in comparison with the case with rotating inner cylinder when rotating with the same rotational reynolds number, and decreases it when rotating with the same rotational speed. the mixed and forced convection heat transfer from an unsteady no-uniform stream shear flow past a rotating isothermal cylinder was studied by (abdella and magpantay, 2007). (fu et al., 1994) investigated numerically enhancement of natural heat transfer in enclosure by a rotating cylinder using a penalty finite element method with newton-raphson iteration algorithm. they found that the contribution of the rotating cylinder to natural heat transfer depends on the direction of rotation of the cylinder, also for counter clockwise rotation cylinder situation, the contribution was found to be substantial when the value of 2re/gr is greater than 100, however the maximum enhancement of the heat transfer rate is approximately equal to 60%. (costa and raimundo, 2010) studied numerically mixed convection in a square enclosure with a rotating concentric cylinder. it is explored the influence of the cylinder through its radius, rotating velocity, thermal conductivity and thermal capacity on the resulting mixed convection. the overall thermal performance of the enclosure was analyzed through the overall nusselt number. they observed that the al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 98 size of the cylinder has strong influence on the resulting flow and heat transfer process, as it limits the space for fluid flow between the cylinder and the enclosure walls, giving rise to higher or lower local fluid velocities close to solid boundaries, also they concluded for high values of the cylinder radius, the overall nusselt number is small if the rotating velocity is low, and it considerably increase in a nearly linear way, with the rotating velocity absolute value, for both the situations of possible combination of the natural and forced convection effects. the aim of the present study is to investigate the effect of a single or multi rotating horizontal cylinders in an equilateral triangular enclosure on the mixed heat transfer. and to solve governing equations (continuity, momentum and energy) using penalty finite element method. and to show the influence of rotating cylinders velocity, the direction of rotating velocity, radius of cylinder and rayleigh number on velocities and temperature distribution and then on the average nusselt number. also to illustrate the difference between single-cylinder and multi-cylinders having constant cylinder (cylinders) to total enclosure volume ratio. theoretical analysis the schematic diagram of the problem of mixed convection heat transfer inside equilateral triangular enclosure with height h and base b for single and multi rotating solid horizontal cylinder at angular velocity ω, is shown in figure1 (a) and (b) respectively. the ratio of solid rotating cylinder volume to total triangle enclosure volume for single or multi cylinder is constant and equal to 0.25. the viscous dissipation term in the energy equation and radiation are neglected. the governing equations for the steady, laminar, two dimensional, incompressible flow with boussinseq approximation (kreith and bohn, 1997) and constant fluid properties can be written in nondimensional form as follows: -continuity equation 0= ∂ ∂ + ∂ ∂ y v x u (1) -the momentum equations         ∂ ∂ + ∂ ∂ + ∂ ∂ −= ∂ ∂ + ∂ ∂ 2 2 2 2 pr y u x u x p y u v x u u (2) and θprpr 2 2 2 2 ra y v x v y p y v v x v u +       ∂ ∂ + ∂ ∂ + ∂ ∂ −= ∂ ∂ + ∂ ∂ (3) -energy equation 2 2 2 2 yxy v x u ∂ ∂ + ∂ ∂ = ∂ ∂ + ∂ ∂ θθθθ (4) where the dimensionless variables are defined as: ch c tt ttvh v uh u h r r h y y h x x − − ====== θ αα ,,,,, al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 99 α ω να β α ν αρ ρ 23 2 2 )( ,pr, )( h and httg ra hgyp p chc =ω − == + = with boundary conditions 1u=v=0 and θ=1 at the base of triangular enclosure 2 u=v=0 and θ=0 at the left wall of triangular enclosure 3 u=v=0 and 0= ∂ ∂ n θ at the right wall of triangular enclosure 4 )x-(x-=v ),y-(y= u oo ωω and 0=∂ ∂ n θ at the wall of rotating solid cylinder 50= ∂ ∂ n p at all the walls where )y,(x oo : the center of cylinder. hence: (1)the center of rotating solid cylinder is constant, at the origin point 0,0x o == oy for single rotating cylinder, and ),0( e , )60cos,60sin( °−° ee and )60cos,60sin( °−°− ee for three rotating cylinders respectively, (2)the three cylinders are distributed on the centers circle which has the radius e and equally distributed on it by )120( ° , (3)the sign of u and v at the wall of cylinder is varied with direction of rotating solid cylinder, and (4)two directions of rotating are used: clockwise cw (positive direction) and counter-clockwise ccw (negative direction). the average nusselt number at the heated wall is calculated by dx y nu hy av ∫ − −=       ∂ ∂ −= 2/1 2/1 3/ θ (5) and the bulk average temperature is defined as ∫= v vd av θθ (6) where v : the volume of occupying fluid in triangular enclosure. numerical solution in the present study, a finite element software package flexpde (backstrom, 2005) is applied in the solution of the nonlinear system of equations (1) to (4). hence, the continuity equation (1) is used to check the error of the solution throughout the grids of domain. the penalty finite element method are applied to overcome the linkage between velocity and pressure in the momentum equations using continuity equation       ∂ ∂ + ∂ ∂ =∇ y v x u p γ2 (7) where; γ is a setting parameter. the continuity equation is automatically satisfied for large value of penalty parameter γ. typical values of γ that yield consistent solutions are 610 . the relative error limit which is employed in this study is less than 310− . al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 100 validation and comparison of the study to check the validation of software, the continuity equation ( 0= ∂ ∂ + ∂ ∂ y v x u ) is used. figure 2(a) shows the validity of continuity equation of single rotating cylinder with ω=500ccw, figure 2(b) illustrates the validity of continuity equation for three rotating cylinders with ω=500ccw, it can be seen exactly validated of the velocity distribution of the values ( 0= ∂ ∂ + ∂ ∂ y v x u ) over the domain. also, the present model is compared with results of (costa and raimundo, 2010) as shown in figure 3, for r=0.2. the comparison represent the variation of the average nusselt number with dimensionless angular velocity at constant the other parameters, 7.0pr,105 ==ra and the ratio of thermal conductivity of solid to fluid and the heat capacity of solid to fluid equal to one. the results show a good agreement and from this comparison it can be decided that the current code can be used to predict the flow field for the present problem. results and discussion the results are represented for three cases: case (i) single rotating horizontal cylinder at constant position with two direction of rotating cw or ccw, case (ii) three rotating horizontal cylinders at constant positions with the same direction of rotating cw or ccw, case (iii) three rotating horizontal cylinders at constant positions with the different directions of rotating (the upper and right lower cylinders at the same direction while the left lower cylinder is inversed them). the fluid in enclosure is air, pr=0.7. the values of rayleigh number varying over the range of 52 1010 − . the dimensionless rotating velocities of cylinder ω are varied from 0 to 1000 with two directions cw and ccw. the ratio of rotating cylinder volume to total volume of triangular enclosure in single cylinder or three cylinders is constant and equal to 0.25, and the radius of centers circle of each cylinder from the center of triangular for the multi cylinders is e=0.25. a-flow and isotherms fields isingle rotating cylinder fig.4 shows the counters of u-velocity (left), v-velocity (middle) and isotherm lines (right) for 7.0pr,103 ==ra and 214.0=r . it shows that when ω=0, the both velocities u and v have the minimum values comparison with the ω=500cw or ω=500ccw, and for u-velocity distribution a cellular motion is formed near the upper and bottom surfaces of the cylinder as shown in figure 4a(left). figure 4a (middle) shows that the cellular motion of the v-velocity distribution. it is occurred near the upper surface of the cylinder, this is because of the effect of the secondary flow. for the rotating cylinder, the maximum values of v-velocity are occurred near the both left and right sides of the cylinder as shown in figure 4 (middle) b and c, this can be understood from the definition of u and v respect to dimensionless angular velocity ω. figure 4a (right) represents the isotherm lines for non-rotating cylinder. it can be seen a curvature lines are concentrated in the left corner of the enclosure, also the isotherm lines are symmetric between the cold and hot surfaces due to the dominant of the natural convection. the effect of the rotating flow by the cylinder increases the density of the isotherm lines which covers most of the enclosure spaces, also the effect of the rotation in both direction are predicted in figure 4b (right) and figure 4c (right). the rotating velocity tends to transfer the heat transfer toward the rotation direction. figure 5 shows the counters of u-velocity (left), v-velocity (middle) and isotherms (right) for high rayleigh number 510=ra and 214.0=r . it can be seen the curves behavior of the u-velocity and v-velocity are the same as that in figure 4, a deformation of velocity distributions is occurred in same al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 101 regions near the cylinder surface due to the strong effect of secondary flow. for non-rotating cylinder shown in figure 5a (right) the isotherms lines are covered most the cavity space while for the rotating cylinder as in figure 5 b and c the density of the lines is higher than that in figure 4b and c respectively. this is because of the increasing of the vortices flow with increasing of ra (effect of natural convection) and with the increasing the rotating velocity (effect of forced convection). ii-multi rotating cylinders in the same direction this case is for three rotating cylinders with constant ratio of the volume of cylinders to total volume of equilateral triangle which equal to 0.25. figure 6 illustrates the contours of u-velocity, vvelocity and isotherms for 310=ra and 124.0=r . figure 6a indicates a multi cellular motion of u and v velocity distributions while the isotherms show a uniform curvature lines from the left corner of the enclosure toward the cold wall. figure 6 b and c, show the velocity fields and isotherms for rotating multi cylinder in both directions. the behavior of the curves is the same for single cylinder shown in figure 4 b and c. it shows that the maximum values of u and v are smaller than the values of single cylinder at constant angular velocity ω because the radius of three cylinders is less than the radius of single cylinder. the isotherms lines become more interacted than the case of single cylinder, also the isotherms lines become more symmetric for non-rotating cylinders. iii-multi rotating cylinders in the deferent directions figure 7 represents the behavior of three rotating cylinders in a different directions for 310=ra , pr=0.7 and 124.0=r . the volumetric ratio is 0.25 and the radius ratio of centers circle of cylinders is 0.25. three configurations are studied, configuration (1): the three cylinders with ω=0 as shown in figure 7a, configuration (2): the upper cylinder and the right lower cylinder are rotated with ω=500 ccw, while the left lower cylinder is rotated with ω=500 cw as shown in figure 7b. configuration (3): the upper cylinder and the right lower cylinder are rotated with ω=500 cw while the left lower cylinder is rotated with ω=500 ccw as shown in figure 7c. it can be show from this figure; the locations of maximum u-velocity and v-velocity near the rotating cylinders are dependent on the direction of the rotation. for isotherms, figure 7 (right) illustrates a curvature of isotherms lines are cover all the enclosure space in both directions. also it can be seen the growth of the thermal boundary layer near the heated bottom wall of the cavity for configuration (3) is higher than that of configuration(2) due to the strongly effect of the rotation (forced convection). bheat transfers field i-single rotating cylinder figure 8a illustrates the variation of the average nusselt number with rayleigh number for single rotating cylinder for 214.0=r and ω=500ccw, while figure 8b shows the variation of the bulk mean temperature with rayleigh number for the same above parameters. it indicates that the bulk air temperature is increased with increasing of ra, it may be attributed to increase bouncy effecting so that the growth of the thermal boundary layer is increased near the heated surface leading to increase the average nusselt number and enhancement the heat transfer process with increasing rayleigh number as shown in figure 8a. the effect of dimensionless angular velocity ω of rotating single cylinder on the average nusselt number and on the mean bulk temperature for 310=ra and 214.0=r is shown in figure 9a and figure 9b respectively. increment of ω in both directions cw and ccw gives enhancement in the average nusselt number due to increase the force convection effect and mixing of fluid i.e. increasing the heat transfer. for the isotherms the behavior is deferent with direction of rotating, which it inversed on the boundary conditions of θ, therefore the direction of rotating make the effect one surface more than the other. figure 10a illustrates the variation of the average nusselt al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 102 number with dimensionless radius of cylinder and figure 10.b shows the variation of mean bulk temperature with dimensionless radius of cylinder, both variations for 310=ra and ω=500ccw. it can be seen avnu and avθ are increased with increasing r, due to decrease the volume of fluid compared to the volume of cylinder and increasing the velocity to satisfy the continuity equation. iimulti rotating cylinders in the same direction figure 11 represents the effect of rayleigh number on avnu and avθ at r=0.124 and ω=500ccw. also, as the single rotating cylinder the ra effect causes an increasing of both avnu and avθ , it may be attributed to increase the temperature difference and bouncy effecting with increasing ra. figure 12 shows variation of the average nusselt number with dimensionless angular velocity and the variation of the average dimensionless temperature with dimensionless angular velocity for three rotating cylinders, at 7.0pr = , 124.0=r and 310=ra . increment of ω in both directions cw and ccw gives increasing in the heat transfer then average nusselt number. the average dimensionless temperature is varied with varying the direction of rotating (increment or decrement), because the changing the direction of rotation makes the effect of cold or hot wall greater than the other. iii-multi rotating cylinders in the deferent directions figure 13a illustrates the variation of the average nusselt number with rayleigh number for multi rotating cylinders when the upper cylinder and the right lower cylinder are rotated with ω=500 ccw while the left lower cylinder is rotated with ω=500 cw, at 124.0=r while figure 13(b) shows the variation of the bulk mean temperature with rayleigh number for the same above configuration. it shows that the bulk air temperature is increased with increases of ra; it may be attributed to increase bouncy effecting so that the average nusselt number is increased. comparison among the three cases the table 1 shows the comparison of avnu and avθ among the three cases at 7.0pr,10 3 ==ra and 214.0=r for single cylinder and 124.0=r for multi cylinders. it illustrates that the varying the direction of rotation of any one of three rotating cylinder gives increment in the average nusselt number due to increase the mixing of the fluid particles and then heat transfer between surfaces. conclusions the governing equations (mass, momentum and energy) for the steady , laminar, two dimensional, incompressible flow with boussinseq approximation and constant fluid properties for rotating single or multi cylinder in equilateral triangular enclosure are solved numerically using finite element method with flexpde soft package. the main conclusions: 1-the average nusselt number is increased with increasing ra, r and ω for both direction of rotating. 2the average nusselt number of single rotating cylinder is greater than the multi rotating cylinders for the same the ratio of the volume of the solid cylinder or cylinders to total enclosure volume. 4-muti rotating cylinders with deferent rotating direction give increment in the mixing effect and then the average nusselt number becomes greater. 5-when the angular rotating velocity equal to zero the behavior becomes of natural convection only. references abdella, k., magpantay, f., (2007) "approximate analytic solutions for mixed and forced convection heat transfer from an unsteady no-uniform flow past a rotating cylinder", wseas transactions on heat transfer, issue 1,volume 2. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 103 ashjaee, m., rajaian, m., moghadasian, b., (2008) " numerical computation of convective heat transfer from an annular gap of eccentric cylinders with inner and outer cylinder rotating"8th word congress on computational mechanics (wccm8), venice, italy. backstrom, g. 2005 "fields of physics by finite element analysis using flexpde" by gb publishing and gunnar backstrom malmo, sweden. braga, e. j., de lemos, m. j.s., (2005) "laminar natural convection in cavities filled with circular and square rods” int. j. heat and mass transfer, 32, 1289-1297. costa, v. a.f., raimundo, a.m., (2010) " steady mixed convection in a differentially heated square enclosure with an active rotating circular cylinder" int. j. heat and mass transfer, 53, 1208-1219. fu, w.-s., cheng, c.-s., and shieh, w.-j.,(1994) " enhancement of natural convection heat transfer of an enclosure by a rotating circular cylinder" int. j. heat and mass transfer, vol.37, no.13, pp.18851897. kim, b. s., lee, d. s., ha, m. y., yoon, h. s., (2008), “a numerical study of natural convection in a square enclosure with a circular cylinder at different vertical locations,"int. j. heat and mass transfer, 51, 1888-1906. kreith, f., bohn, m. s., (1997), “principles of heat transfer", pws publishing company, u.s.a. rahman, md. m., alim, m. a., mamun, m. a., (2009) "finite element analysis of mixed convection in a rectangular cavity with a heat-conducting horizontal circular cylinder", nonlinear analysis: modeling and control, vol. 14, no.2, 217-247. shu, c., xue, h., zhu, y.d., (2001) "numerical study of natural convection in an eccentric annulus between a square outer cylinder and a circular inner cylinder using dq method" int. j. heat and mass transfer, 44, 3321-3333. yu, z.-t., fan, l.-w., hu, y.-c., cen, k.-f., (2010) " prandtl number dependence of laminar natural convection heat transfer in a horizontal cylindrical enclosure with an inner coaxial triangular cylinder" int. j. heat and mass transfer, 53, 1333-1340. table1 the comparison of avnu and avθ among the three cases. no. of case rotating velocity ω avnu avθ case i 500ccw 500cw 7.7612 7.7576 0.5584 0.4422 case ii 500ccw 500cw 7.0212 7.0113 0.5843 0.4166 case iii i-500ccw the upper cylinder & right lower cylinder, 500cw left lower cylinder ii-500cw the upper cylinder & right lower cylinder, 500ccw left lower cylinder 7.5317 7.5304 0.4824 0.5184 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 104 (a) (b) figure 1 sketch of the physical model (a) single rotating cylinder (b) three rotating cylinders. (a) (b) figure 2 verfication of numerical approach(countours of continuity equation) for 7.0pr,103 ==ra and ω=500ccw. (a) single rotating cylinder, (b) multi rotating cylinders figure 3 comparison between the present study and results of (costa and raimundo, 2010) for 7.0pr,105 ==ra and r=0.2. ω avnu (costa and raimundo, 2010) present study al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 105 (a) (b) (c) figure 4 u-velocity (left), v-velocity (middle) and isotherms (right) for single cylinder, 310=ra and 214.0=r and (a) ω=0 (b) ω=500ccw (c) ω=500cw. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 106 (a) (b) (c) figure 5 u-velocity (left), v-velocity (middle) and isotherms (right) for single cylinder, 510=ra and 214.0=r . (a) ω=0 (b) ω=500ccw (c) ω=500cw. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 107 (a) (b) (c) figure 6 u-velocity (left), v-velocity (middle) and isotherms (right) for multi cylinders rotating at the same direction, 310=ra and 124.0=r . (a) ω=0 (b) ω=500ccw (c) ω=500cw. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 108 (a) (b) (c) figure 7 u-velocity (left), v-velocity (middle) and isotherms (right) for multi cylinders, 310=ra and 124.0=r . (a)the three cylinders have ω=0 (b) the upper and the right lower cylinders are rotated with 500ccw and the left lower cylinder is rotated by 500cw, (c)the upper and the right lower cylinders are rotated 500cw and the left lower cylinder is rotated by 500ccw. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 109 (a) (b) figure 8 (a) variation of the average nusselt number with rayleigh number (b) variation of the average dimensionless temperature with rayleigh number, for single rotating cylinder, at 214.0=r and ω=500ccw. (a) (b) figure 9 (a) variation of the average nusselt number with dimensionless angular velocity (b) variation of the average dimensionless temperature with dimensionless angular velocity, for single cylinder at 310=ra and 214.0=r . (a) (b) figure 10 (a) variation of the average nusselt number with dimensionless radius of cylinder (b) variation of the average dimensionless temperature with dimensionless radius of cylinder, for single cylinder, at 310=ra and ω=500ccw. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 110 (a) (b) figure 11 (a) variation of the average nusselt number with rayleigh number (b)variation of the average dimensionless temperature with rayleigh number for three cylinders rotating at the same direction, and 124.0=r and ω=500ccw. (a) (b) figure 12 (a) variation of the average nusselt number with dimensionless angular velocity (b)variation of the average dimensionless temperature with dimensionless angular velocity, for three cylinders rotating at the same direction, at 310=ra and 124.0=r . (a) (b) figure 13 (a) variation of the average nusselt number with rayleigh number (b)variation of the average dimensionless temperature with rayleigh number, for three cylinders rotating at deferent directions, and 124.0=r . al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 133 thermal design of tube banks in cross flow based on minimum thermodynamic losses ass. proff. dr. abbas a. s. aljeebori college of engineering-al-qadisiya university mechanical engineering departments abstract tube banks are widely used in crossflow heat exchangers. usually, the methods for its design are the ntu or lmtd methods, while in this research the entropy generation method is used. by assuming constant tube wall temperature, a general dimensionless expression for the entropy generation rate is obtained by considering a control volume around a tube bank and applying the conservation equations for mass and energy with the entropy balance. a comparison of the design is accomplished for a tube banks of different stream velocity, lengths and diameters. the heat transferred rate, ambient and tube wall temperatures are 20kw, 300k, and 365k, respectively. from the comparison of the design with the entropy generation rates, the optimal design is obtained. a single objective function is used which is the dimensionless entropy generation rate ns subjected to the constraints of diameters and pitch ratio. this method of optimization can be applied for any constraints on the system which is the lagrange optimization method. the effects of tube diameter, tube length, dimensionless pitch ratios, front cross-sectional area of the tube bank, and heat load are examined with respect to its role in influencing optimum design conditions and the overall performance of the tube banks. it is demonstrated that the performance is better for higher air velocities and larger dimensionless pitch ratios. compact tube banks perform better performance for smaller tube diameters. key words: entropy , generation ,tube bank , crossflow ,performance الخسائر الثرموديناميكية اقل على باالعتماد متقاطع في جريان أنابيب التصميم الحراري لحزمة عباس علوي الجبوري. د.م.أ جامعة القادسيةآلية الهندسة قسم الهندسة الميكانيكية الخالصة قة هي طري عة لتصميها الطرق الشائ إنآما . في المبادالت الحرارية ذات الجريان المتقاطع االستخدامواسعة حزم األنابيب إن ntu وطريقة lmtd تولد األنتروبي اما في هذا البحث نستخدم طريقة جديدة وهي طريقة entropy generation method تم الحصول على تعبير رياضي عام لمعدل تولد األنتروبي بشكل البعدي حيث ثابتة األنابيب جدران درجة حرارة إنتم افتراض . dimensionless على حجم التحكم للطاقة واألنتروبي موازنة معادالت حفظ الكتلة والطاقة مع خالل تطبيق منc.v المأخوذ حول مختلفة يكون معدل في هذا البحث تم مقارنة تولد األنتروبي لحزمة أنابيب ذات أقطار و أطوال وسرع جريان خارجي .حزمة األنابيب ومن مقارنة معدالت تولد األنتروبي تم 365k األنابيب ودرجة حرارة جدران 300kودرجة حرارة جو 20kwانتقال الحرارة فيها al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 134 خطوة الونسب علىاألقطار وليقيود ns لدالة هدف واحدة وهي معدل تولد األنتروبي الالبعدية ةي األمثل تمت .اختيار التصميم األمثل آذلك تم دراسة .ةي لألمثللنظام وهي طريقة الآرانج تضاف ل constraints قيود أية هذه الطريقة ممكن ان تطبق إنحيث البعدية ال على التصميم واألداء pitch ratio الالبعدية الخطوة نسب إلى باإلضافة مساحة مقطع حزمة األنابيب , تأثير آل من قطر األنبوب . ونسب خطوة البعدية عالية خارجي عالية عند سرعة جريان يكون األمثلاألداء إن إلى تم التوصل . لمنظومة حزمة األنابيب األمثل . صغيرةأنابيبلكال النظامين ألقطار يكون األداء األمثل حزمة األنابيب المتراصة إن nomenclature a surface area of a single tube, m2 at total heat transfer area, m2 d tube diameter, m e specific energy, w f friction factor g, l equality and inequality constraints havg average heat transfer coefficient of tubes, w/m2.k i number of imposed constraints k thermal conductivity, w/m.k lf lagrangian function l length of tube, m n total number of tubes, lt nn n number of design variables ln number of rows in streamwise direction ns dimensionless entropy generation rate, )//( 2max 2 . afgen tkuqs ν tn number of rows in spanwise direction nud nusselt number based on tube diameter p pressure, pa q heat transfer rate over the boundaries of control volume, w dre reynolds number, ν/du max gen . s total entropy generation rate, w/k ls tube streamwise pitch, mm ts tube spanwise pitch, mm t absolute temperature, k u air velocity, m/s pr prandtl number, v specific volume of fluid, kgm /3 ix design variables al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 135 greek symbols γ aspect ratio, d/l ν kinematic viscosity of fluid, sm /2 ρ fluid density, 3/ mkg subscripts a ambient f fluid in inlet of control volume out exit of control volume t thermal w wall superscripts * optimum introduction tube banks are usually arranged in an in-line or staggered manner, where one fluid moves across the tubes, and the other fluid at a different temperature passes through the tubes. this research is interested to determine an optimal design of the tube banks in crossflow using entropy generation minimization method. the crossflow correlations for the heat transfer and pressure drop are employed to calculate entropy generation rate. a careful review of existing literature reveals that most of the studies are related to the optimization of plate heat exchangers and only few studies are related to tube heat exchangers. bejan(1982) extended that concept and presented an optimum design method for balanced and imbalanced counterflow heat exchangers. he proposed the use of a ns as a basic parameter in describing heat exchanger performance. this method was applied to a shell and tube regenerative heat exchanger to obtain the minimum heat transfer area when the amount of units was fixed. aceves-saborio et al.(1989) extended that approach to include a term to account for the exergy of the heat exchanger material. ordonez and bejan(2000), bejan(2001), and bejan(2002) demonstrated that the optimal geometry of a counterflow heat exchanger can be determined based on thermodynamic optimization subject to volume constraint. entropy generation rate is generally used in a dimensionless form. peters and timmerhaus(1991) presented an approach for the optimum design of heat exchangers. they used the method of steepest descent for the minimization of annual total cost. they observed that this approach is more efficient and effective to solve the design problem of heat exchangers. optimization of plate-fin and tube-fin crossflow heat exchangers was presented by shah et al.(1978) and van den bulck(1991). they employed optimal distribution of the ua value across the volume of crossflow heat exchangers and optimized different design variables like fin thickness, fin height, and fin pitch. in two different studies, stanescu et al.(1996) and matos et al.(2001) demostrated that the geometric arrangement of tubes/cylinders in cross-flow forced convection can be optimized for maximum heat transfer subject to overall volume constraint. they used fem to show the optimal spacings between rows of tubes. vargas, et al.(2001) documented the process of determining the internal geometric configuration of a tube bank by optimizing the global performance of the installation that uses the crossflow heat exchanger. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 136 problem formulation the irreversibility of this system is also due to heat transfer across the nonzero temperature difference tw ta and due to the total pressure drop across the tube bank. first law of thermodynamics for the control volume can be written as )( . inout hhmq −= (1) from the second law thermodynamics w inoutgen t q ssms −−= )( .. (2) gibbs equation[ ]dptdsdh )/1( ρ+= can be written as: )( 1 )( inoutinoutainout ppssthh −+−=− ρ (3) combining eqs. (1) and (3), we get: p m sstmq inouta ∆−−= ρ . . )( (4) from eqs. (2) and (4), we get: p t m r tt q s a tube wa gen ∆+⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = ρ . 2. (5) where tuber is the tube wall thermal resistance, . m is the mass flow rate through the tubes and p∆ is the pressure drop across the tube bank and can be written as ahq t r avg tube 1 = ∆ = (6) lsnum ttρ= . (7) ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ =∆ 2 2 1 ufnp l ρ (8) khan(2004) has developed following analytical correlation for dimensionless heat transfer coefficient for the tube banks: 3/12/1 1 prre d f avg d ck dh nu == (9) where and c1 is a constant which depends upon the longitudinal and transverse pitch ratios, arrangement of the tubes, and thermal boundary conditions. for isothermal boundary condition, it is given by: [ ] 212.0285.01 )55.0exp(25.0 ltl sssc −+= (10) khan et al.(2005) digitized thier experimental data and fitted into single correlations for the friction and correction factors for each arrangement. these correlations can be used for any pitch ratio ls≤05.1 or 3≤ts and reynolds number in the laminar flow range. they are ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − + = dts kf re)1( 78.45233.0 1.11 (11) al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 137 where 1k is a correction factor depending upon the flow geometry and arrangement of the tubes. it is given by: 0553.0re/09.1 1 1 1 009.1 d l t s s k ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − − = (12) using eqs. (6) (9), the entropy generation rate can be simplified to a t df wa gen t lsunf lknc ttq s 2 )1( prre / 3 3/12/1 1 2. − += ρ π (13) for external flow, bejan (1996) used the term 22 / af vtkuq to nondimensionalize entropy generation rate in eq. (14). so the dimensionless entropy generation rate can be written as )1(re 2 1 prre / 2 3/12/3 1 −+= td d wa s sbfnnc tt n γ πγ (14) where 23 / qtkvb afρ= optimization procedure if f(x) represent the dimensionless entropy generation rate that is to be minimized subject to equality constraints 0),...,,( 21 =ni xxxg (15) and inequality constraints 0),...,,(( 21 ≥nk xxxl , (16) then the complete mathematical formulation of the optimization problem may be written in the following form: )()(min xnxfimize s= (17) subject to the equality constraints mixgi ,....,2,1,0)( == (18) and inequality constraints nmmixli ,.....,2,1,0)( ++=≥ (19) in this research, the design variables x are: t nxxxxx ),.....,,,( 321= ],,,,,[ qulwhd= (20) inequality constraints are: mmd 10≥ (21) 325.1 ≤≤ d sl (22) 325.1 ≤≤ d st (23) 20≥γ (24) the objective function can be defined by using lagragian function as follows: )()()(),lf(x, 11 xlxgxn i n mi ii m i is ∑∑ +== −+= χλχλ (25) al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 138 where iλ and iχ are the lagrange multipliers. the iλ can be positive or negative but the iχ must be greater than or equal zero. in addition to kuhn-tucker conditions, the other necessary condition for *x to be a local minimum of the problem, under consideration, is that the hessian matrix of l should be positive semidefinite, i.e. 0)],,[( ***2 ≥∇ vxvt χλ (26) for a local minimum to be a global minimum, all the eigen-values of the hessian matrix should be greater than or equal zero. a system of non-linear equations is obtained, which can be solved using numerical methods such as a multivariable newton-raphson method. in this study, the same approach is used to optimize the overall performance of a tube bank in such a manner that all relevant design conditions combine to produce the best possible tube bank for the given constraints. the optimized results are then compared. a simple procedure was programmed in matlab, which solves the system of n non-linear equations using the multivariable newton-raphson method. results and discussion the problem is solved for different pitch ratios and the overall performance is compared for both ntu and lmtd methods. figure 2 shows the effect of tube diameter on the heat transfer from the system of tube banks based on the three different ntu, lmtd, and . gens methods. it is show that the linear relation between the tube diameter and the heat transfer rate based on the lmtd method, while in the . gens and ntu methods , the relation was not linear. this behavior due to the different mathematical formula between each of three methods. lmtd neglect the pressure drop effect, while the . gens take the pressure as the first parameter in its mathematical relation. ntu and . gens method gives the same amount of heat transfer at d=2.05 mm which gives the more accuracy for the ntu method. also the ntu method gives a good convergence for tube diameter less than 2.05 mm, but diverge for the diameter larger than 2.05mm. figure 3 shows the real interpretation for effect of tube bank length on the heat transfer rate. the lmtd and ntu method gives higher heat transfer rate than . gens method. this behavior due to the pressure drop effect. the recommendation for this case is to use entropy generation method to study the tube banks performance when the length is variable. figure 4 shows the real interpretation for the effect of tube banks length on the heat transfer rate. there is a note from the above figure which is at the velocity 12 m/s, the ntu, lmtd, and . gens methods gives the same estimation of the heat transfer rate. also at velocities less than 12 m/s, ntu and . gens converge in estimation of heat transfer rate, while at velocities larger than 12 m/s, the . gens diverge from the ntu and lmtd method because of the pressure losses. the recommendation for this case is to use any method to estimate the heat transfer rate when the air velocity is 12 m/s. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 139 figure 5 shows the effect of the tube pitch on the heat transfer rate. it is noted that the amount of heat transfer decrease when the pitch is increase. also when the mmst 2≈ . the lmtd, . gens , and ntu methods gives the same estimation of the heat rate. heat transfer rate increase after the pitch of 2mm value because of the increasing of the heat transfer area. the recommendation for this case is to use any method for heat transfer rate estimation when pitch is larger than 2mm. conclusions 1this research shows that, for the given volume of the tube bank and heat duty, the dimensionless entropy generation rate depends on ambient and wall temperatures, total number of tubes, longitudinal and transverse pitch ratios, reynolds and prandtl numbers, and aspect ratio. after fixing ambient and wall temperatures, all these parameters depend on tube diameter and the approach velocity for given longitudinal and transverse pitches. 2an entropy generation minimization method is applied as a unique measure to study the thermodynamic losses caused by heat transfer and pressure drop for a fluid in crossflow with tube banks. 3a general dimensionless expression for the entropy generation rate is obtained by considering a control volume around a tube bank and applying the conservation equations for mass and energy with the entropy balance. 4any method can be used for heat transfer rate estimation when pitch is larger than 2mm. also entropy generation method can be used to study the tube banks performance when the length is variable. 5sn method is better than ntu and lmtd methods to find the optimum thermal design for heat sink. references aceves-saborio, s., ranasinghe, j., and reistad, g. m., 1989, “an extension to the irreversibility minimization analysis applied to heat exchangers,” journal of heat transfer, vol. 111, no. 1, pp. 29-36. bejan, a., 1982,“entropy generation through heat and fluid flow,” john wiley & sons, new york. bejan, a., 1996, “entropy generation minimisation: the new thermodynamics of finite-size devices and finite-time processes,” journal of applied physics, vol. 79 no. 3, 1 feb, pp 1191-1218. bejan, a., 2001, “thermodynamic optimization of geometry in engineering flow systems,” exergy, an international journal, vol. 1, no. 4, pp. 269-277. bejan, a., 2002, “fundamentals of exergy analysis, entropy generation minimization, and the generation of flow architecture,” international journal of energy research, vol. 26, pp. 545565. khan, w. a., 2004, “modeling of fluid flow and heat transfer for optimization of pin-fin heat sinks,” ph. d. thesis, department of mechanical engineering, university of waterloo, canada. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 140 khan, w. a., culham, j. r., and yovanovich, m. m.,2005 “convection heat transfer from tube banks in crossflow: analytical approach,” presented at 43rd aiaa aerospace sciences meeting and exhibit, reno, nevada, 10-13 january. matos, r. s., vargas, j. v. c., laursen, t. a., and saboya, f. e. m., 2001, “optimization study and heat transfer comparison of staggered circular and elliptic tubes in forced convection,” international journal of heat and mass transfer, vol. 44, pp. 3953-3961. ordonez j.c., and bejan a., 2000, “entropy generation minimization in parallel-plates counterflow heat exchangers,” international journal of energy research, vol. 24, pp. 843-864. peters, m, and timmerhaus, k., 1991, “plant design and economics for chemical engineers,” 4th ed. mcgraw-hill, singapore. shah, r. k., afimiwala, k. a., and mayne, r. w., 1978, “heat exchanger optimization,” proceedings of sixth international heat transfer conference, vol. 4, hemisphere publishing corporation, washington, dc, pp. 185-191. stanescu, g., fowler, a. j. and bejan, a., 1996, “the optimal spacing of cylinders in free-stream crossflow forced convection,” int. j. heat mass transfer, vol. 39, no. 2, pp. 311-317. van den bulck, e., 1991, “optimal design of crossflow heat exchangers,” journal of heat transfer, vol. 113, pp. 341-347. vargas, jose v. c., bejan, a., and siems, d. l., 2001, “integrative thermodynamic optimization of the crossflow heat exchanger for an aircraft environmental control system,” transactions of the asme, august, vol. 123, pp. 760-769. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 141 fig. 1: front view control volume for calculating gens . for the tube banks of length l. fig. 2: comparison of optimum heat loss between lmtd, . gens , and ntu methods based on tube diameter. 5.1 6.1 7.1 8.1 9.1 1.20.2 )(wq )(mmd 5000 10000 15000 20000 lmtd ntu . gens u app cv st w h ta sl tw al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 142 fig. 3: comparison of optimum heat loss between lmtd, . gens , and ntu methods based on tube length. fig. 4: comparison of optimum heat loss between lmtd, . gens , and ntu methods based on air velocity. )(wq 5000 10000 15000 20000 )(mml 300 400 500 600 700 800 900 1000 lmtd ntu . gens )(wq 5 0 0 0 1 0 0 0 0 1 5 0 0 0 2 0 0 0 0 0.1 l m t d n t u . g e ns )/( smu 0.6 8 0.1 0 0.1 2 0.1 4 0.1 6 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 143 fig. 5: comparison of optimum heat loss between lmtd, . gens , and ntu methods based on tube on tube pitch. )(wq 5000 10000 15000 20000 0.1 lmtd . gen s ntu 125 )(mms t 5.1 75.1 0.2 25.2 5.2 0.3 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012 439 some properties of fiber reinforced no fine concrete hussam a. a. rehman assist. lecturer civil engineering department/wasit university hussam4s@yahoo.com . abstract this work focus on studying the mechanical characteristics of polypropylene and carbon fiber reinforced no fine aggregate concrete, containing different percentages of fiber. this work was carried out using several tests. these tests were workability fresh and hardened density, compressive strength, splitting tensile strength and modulus of rupture. tests were performed for specimens at ages of (7, 28) days. the test results indicated that the inclusion of fiber to the pervious concrete mixes did not affect the compressive strength significantly, while the splitting tensile strength and the modulus of rupture were improved significantly. test results indicated that, the modulus of rupture of (5%) carbon fiber pervious concrete specimens are three times that of the control specimens, while the modulus of rupture of (5%) polypropylene fiber pervious concrete specimens are two times that of the control specimens. the percentage increase in tensile strength for polypropylene mixes containing fiber by volume fraction of (1%, 3%, 5%) were (93%, 101% and 129%) respectively and the percentage increase in tensile strength for carbon mixes containing fiber by volume fraction of (1%, 3%, 5%) were (170%, 177% and 220%) respectively. keywords: no fine concrete, carbon fiber, polypropylene fiber, flexural strength. 7 28 5 hussam a. a. rehman al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012440 13593101129 13593 101129 1. introduction no-fines concrete (nfc) is an open textured cellular concrete and it’s a type of light weight concrete ,obtained by eliminating either fines or sand from the normal concrete mix. the alleged advantages of this type of light weight porous concrete include its lower cement content (resulting in lower cost), lower density, lower thermal conductivity, no segregation and, better insulating characteristics, than conventional concrete. a limited number of researches have been carried out to investigate the mechanical properties of fiber reinforced no fine concrete (nfc). however there have been many works on the mechanical characteristics of fiber reinforced normal concrete. no-fines concrete consists solely of normal portland cement, water and coarse aggregate. the compressive strength of no-fines concrete is considerably lower than that of conventional portland cement concrete and varies between (4 to 25) mpa [1]. the ratio of modulus of rupture to compressive strength expressed as a percentage varies between 10.8 and 31.0 percent [2]. the principal advantages claimed for no-fines concrete are economy in materials, somewhat higher thermal insulating values, lower shrinkage, and lower unit weight. the major disadvantages are its low compressive, flexural, and bond strength, and higher permeability. the principal applications for no-fines concrete are for load-bearing cast-in-place external walls of single story and multistory housing, small retaining walls, and as a dam proofing sub-base material for concrete floors cat on grade. fiber reinforced no fine concrete (nfc) has a little application in iraq. however, light weight carbon fiber reinforced concrete with micro balloons as aggregate has been successfully used in the construction of al-shaheed monument in iraq [3]. the density of nfc depends on the properties and proportions of the materials used. also it depends of the compaction procedure used in placement; generally the density ranges in1600-2000 kg/m 3 [4]. the tensile and flexural strength is increases with increasing fiber content (2 to 10%) by volume. the handling and the fabrication create some problems at volume fraction above 10% [5]. 2. experimental program ordinary portland cement and crashed coarse aggregate of (14 mm) mas was used to produce structural no fine concrete, carbon and polypropylene fibers were also used in this study with different volumetric percentages to improve the flexural strength of no fine aggregate concrete. 3. materials 3.1 cement ordinary portland cement (type i) was used in all mixes throughout this investigation. it was stored in air – tight plastic containers to avoid exposure to atmospheric conditions. the percentage oxide composition indicated that the adopted cement conforms to the iraqi specification no. 5/1984 [6], table 1 and 2 shows the physical and chemical properties of opc. 3.2 coarse aggregate crushed gravel of two different maximum aggregate sizes (mas) (10) mm from wasit, badra region is used. table 3 shows the grading of these aggregate, which conforms to the iraqi specification no. 45/1984[7]. the specific gravity, sulfate content and absorption of coarse aggregate are illustrated in table 4. some properties of fiber reinforced no fine concrete 441al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012 3.3 carbon fiber the properties of carbon fibers, such as high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion, make them very popular in civil engineering and other fields. however, they are relatively expensive when compared to similar fibers, such as glass fibers or polypropylene fibers. table 5 shows the general properties of the used carbon fiber. 3.4 polypropylene fiber the properties of polypropylene fibers, such as fiber shape and dimensions, tensile strength, density, elastic modulus and elongation are illustrated in table 6. 4. concrete mixes concrete mixes with no fine aggregate as a type of light weight concrete should have a dry density less than (2000 kg/m³) and a compressive strength great than (15 mpa) to produce structural concrete. these mixes were obtained by several trial mixes. the mix proportions of all concrete mixes are shown in table 7. 5. mixing, casting and curing of samples all concrete samples (cubes, cylinders and prisms) are casted in steel molds. they were cleaned and oiled before casting. the fresh concrete was placed inside the molds with approximately three equal layers and compacted by means of vibrating table. care was taken to avoid segregation of mixes as shown in plate 1. after the top layer had been compacted, it was smoothed and then the mold covered with wetted gunny sheets for 24 hours to prevent evaporation of water so as to avoid the plastic shrinkage cracks as shown in plate 2. after 24 hours the specimens were demolded and completely covered with wetted gunny sheets until the day of testing. 6. testing program 6.1 unit weight the unit weight of hardened concrete were measured according to astm c567 [8] specifications respectively. 6.2 compressive strength compressive strength tests were conducted using (150) mm cubes using an electrical testing machine with a capacity of (2000 kn) at loading rate of (15 mpa) per minute. this test was determined according to b.s. 1881: part 116: 1984[9].the average of three cubes was adopted for each test. the test was conducted at ages of (7 and 28) days as shown in plate 3. 6.3 splitting tensile strength splitting tensile strength test was performed according to astm c496/c496 m-04 [10] using of (150× 300) mm cylinder. the test was conducted at age of (7 and 28) days. the average splitting tensile strength of three cylinders was adopted, as shown in plate 4. 6.4 modulus of rupture modulus of rupture of concrete was measured on (100 ×100× 500) mm specimens according to astm c78-02[11]. the prisms were subjected to twopoint loading. specimens were tested at age of (7 and 28) days as shown in plate 5. http://en.wikipedia.org/wiki/glass_(fiber hussam a. a. rehman al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012442 7. results and discussions 7.1 unit weight the 7 and 28 day air dry density of all types of concrete mixtures is presented in table 8. results show that the 7 and 28 day air dry densities of (nfc) mixes produced from local naturally aggregate are conformed to the requirement of aci 213-r-87. for structural pervious concrete, the air dry densities should be ranged between (1821-1854) kg/m 3 , however all concrete mixes conform to the requirements of (lwc) according to aci limits the maximum density to 2000 kg/m³. results show that (nfc) mixes without fibers have higher density than fiber reinforced (nfc) mixes containing polypropylene and carbon. 7.2 compressive strength the compressive strength development for all types of mixes is presented in figure 1. test results illustrate that in general, reference pervious concrete and polypropylene and carbon fiber reinforced pervious concrete specimens exhibited continuous development in strength up to 7 and 28 days of curing. there is a considerable improvement in strength for mixes containing fibers. there was a slight increase in the compressive strength with increasing the fiber volume fraction, unless the fiber volume is so high leading the air voids content to become excessively high. the air voids tends to have a negative effect on the compressive strength. 7.3 splitting tensile strength results of splitting tensile strength of various types of reinforced fiber concrete mixes cured with per lab sheets up to 7 and 28 days are demonstrated in figure 2. the incorporation of polypropylene and carbon fiber leads to higher splitting tensile strength compared to their corresponding reference concrete. the tensile strength of the fiber concrete mixes increases with the increase of fiber volume content. this is due to the nature of binding effect of fiber available in concrete matrix. the control batch specimens containing no fiber failed suddenly once the concrete cracked, while the fiber reinforced concrete specimens were still intact together. this shows that the fiber reinforced pervious concrete has the ability to absorb energy in the postcracking state. the comparison of percentage difference in splitting tensile strength for both polypropylene and carbon fiber reinforced pervious concrete to its control batch is presented below, for example the percentage increase in tensile strength for polypropylene mixes containing fiber by volume fraction of (1%, 3%, 5%) were (93%, 101% and 129%) respectively and the percentage increase in tensile strength for carbon mixes containing fiber by volume fraction of (1%, 3%, 5%) were (170%, 177% and 220%) respectively. 7.4 flexural strength the influence of fiber content on the modulus of rupture for all types of fiber reinforced pervious concrete specimens is presented in figure 3. results demonstrate that all concrete specimens exhibited considerable increase in flexural strength with increasing fiber content. the modulus of rupture trend for carbon fiber varies as the volume fraction of fiber is increased. it is found that, the modulus of rupture increases as the fiber volume fraction is increased. the concrete specimens containing no carbon fibers are cracked and failed in a brittle manner when strain in concrete reached its ultimate value. however, fiber reinforced concrete also cracked at ultimate strain, but the section is still capable to carry the load well after the initiation of the first crack .test results indicated that, the modulus of rupture of (5%) carbon fiber pervious concrete specimens are three times that of the control specimens, while the modulus of rupture of (5%) polypropylene fiber pervious concrete specimens are two times that of the control specimens. some properties of fiber reinforced no fine concrete 443al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012 8. conclusions on the basis of seven mixes described in the text, using three variables: two types of fiber (polypropylene and carbon), three different percentages for each of fiber (1, 3 and 5 %), and these mixes are tested in compressive, flexural and splitting tensile strength at age of 7 and 28 days, main conclusions can be summarized, as follows: 8.1 density results show that the pervious concrete mixes without fibers have higher density than fiber reinforced pervious concrete mixes containing polypropylene and carbon. however, the air dry densities should be ranged between (1821 1854) kg. 8.2 compressive strength there was a slight increase in the compressive strength with increasing the fiber volume fraction, unless the fiber volume is so high leading the air voids content to become excessively high. the air voids tends to have a negative effect on the compressive strength. 8.3 flexural strength test results indicated that, the modulus of rupture of (5%) carbon fiber pervious concrete specimens are three times that of the control specimens, while the modulus of rupture of (5%) polypropylene fiber pervious concrete specimens are two times that of the control specimens. 8.4 splitting tensile strength the comparison of percentage difference in splitting tensile strength for both polypropylene and carbon fiber reinforced pervious concrete to its control batch. for example the percentage increase in tensile strength for polypropylene mixes containing fiber by volume fraction of (1%, 3%, 5%) were (93%, 101% and 129%) respectively and the percentage increase in tensile strength for carbon mixes containing fiber by volume fraction of (1%, 3%, 5%) were (170%, 177% and 220%) respectively. 9. recommendations for future works the work carried out in this work can be considered as a key for further work such as: 1. studying the mechanical properties of polypropylene and carbon fiber with light weight aggregate concrete. 2. studying the durability of fiber reinforced no fine aggregate concrete. 3. studying the effect of addition pozolanic materials on the properties of no fine aggregate concrete. 10. references 1. schaefer, v.r., et al (2006), "an overview of pervious concrete applications in storm water management and pavement system", iowa state university, ames. 2. malhotra, v.m., "no fine concrete-its properties and applications", state of the art report, aci journal, november 1976, pp. 628. 3. akihama, s. sueenage t. and banno, j. “mechanical properties of carbon fiber reinforced cement composite and the applications of large domes” kajime institute of construction technology, tokyo, jpan, july 1984. 4. tennis, p.d., leming, m.l. and akers, d.j., (2004) "pervious concrete pavement", old ochard road, skokie: portland cement association. hussam a. a. rehman al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012444 5. saker s. and bailey. m." structural properties of carbon fiber reinforced cement" rilem symposium on fiber reinforced and concrete, september 1975, pp.361-371. 6. iraqi specifications no. 5, “portland cement”, baghdad, 1984. 7. iraqi specifications no. 45, “natural sources for gravel that is used in concrete and construction”, baghdad, 1984. 8. astm standards: c 567-02, “standard test method for determining density of structural lightweight concrete”, astm international. 9. 10. bs 8110:part2, “structural use of concrete: code of practice for special circumstances”, british standard institute, london, 1997. 11. astm standards: c 496-02, “standard test method for splitting tensile strength of cylindrical concrete specimens”, astm international. 12. astm standards: c78-84, “flexural strength of concrete [using simple beam with third point loading”, astm international. table 1 chemical composition of cement compound composition (oxides) chemical composition percentage by weight limits of iqs 5:1984 (7) calcium oxide cao 62.98 - silicon dioxide sio2 21.45 - iron oxide fe2o3 3.64 - aluminum oxide al2o3 5.63 - magnesium oxide mgo 2.39 <5 sulphur trioxide so3 2.57 <2.8 lime saturation factor l.s.f 0.73 0.66 – 1.02 loss on ignition l.o.i 2.19 <4 insoluble residue i.r 0.4 <1.5 tricalicum silicate c3s 42.94 - dicalicum silicate c2s 29.18 - tricalicium aluminates c3a 8.76 - tetracalicum aluminates ferrite c4af 11.06 - some properties of fiber reinforced no fine concrete 445al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012 table 2 physical properties of cement properties test results iqs 5: 1984 criteria (7) fineness using blaine air permeability apparatus (m 2 /kg) 464 >230 setting time using vicat's method initial (hrs:min) final (hrs: min) 1:45 3:45 >45 min <10 hrs soundness using autoclave method 0.19% <0.80% compressive strength 3 day 7 day 28 day* 26.7 38.9 45.6 >15 >23 ---- * the 28-day compressive strength is now a compulsory test in most international standards. table 3 grading of coarse aggregate of mas (10) mm sieve size (mm) % passing by weight limits of the iraqi specification no. 45/1984 (8) 14 100 100 10 93 85-100 5 22 0-25 2.36 5 0-5 table 4 other properties of coarse aggregate of mas (10) mm physical properties test results limits of the iraqi specification no. 45/1984 (8) specific gravity 2.55 - sulfate content 0.06%  0.1% absorption 1.15% - table 6 physical properties of carbon fiber* property value nominal diameter (mm) 0.13 tensile strength (mpa) 4300 fiber length (mm) 10 density (g/cm 3 ) 1.76 elastic modulus (gpa) 238 elongation (%) 1.8 * provided by the manufacturer hussam a. a. rehman al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012446 table 7 characteristics of polypropylene fiber* properties thick fiber fine fiber nominal diameter (mm) 0.98 0.022 tensile strength (mpa) 240 400 fiber length (mm) 10 10 density (g/cm 3 ) 0.88-0.92 0.91 elastic modulus (mpa) 5100 8500 elongation (%) 24.4 12 shape wavy flat * provided by the manufacturer table 8 unit weight of all mixes. mix designation % of fiber by volume w/c ratio by wt. unit weight air dry density (28 days) kg/m³ npc 0 0.3 1890 pfc1 1 0.3 1848 pfc3 3 0.3 1833 pfc5 5 0.3 1821 cfc1 1 0.3 1854 cfc3 3 0.3 1846 cfc5 5 0.3 1830 figure 1 relationship between compressive strength and percent of fiber by volume. some properties of fiber reinforced no fine concrete 447al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012 figure 2 relationship between flexural strength and percent of fiber by volume figure 3 relationship between splitting tensile strength and percent of fiber by volume hussam a. a. rehman al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012448 plate 1 no fine concrete mixture. plate 2 curing of concrete samples with wetted gunny sheets some properties of fiber reinforced no fine concrete 449al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012 plate 3 compressive strength test machine plate 4 splitting tensile strength test machine hussam a. a. rehman al-qadisiya journal for engineering sciences, vol. 5, no. 4, 439-450, year 2012450 plate 5 flexural strength test machine table 1 chemical composition of cement table 2 physical properties of cement * the 28-day compressive strength is now a compulsory test in most international standards. table 3 grading of coarse aggregate of mas (10) mm table 4 other properties of coarse aggregate of mas (10) mm al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 1 performance improvement of water treatment plants in iraq by cfd model abstract the aim of this study is to improve the operation and performance water treatment plant by improving circular sedimentation tanks of al-gazaer water treatment plants in al-dewanyia city in iraq which have been identified as operating poorly. a developed model of the circular settling tanks for the water treatment plant of al-gazaer was prepared using computational fluid dynamics (cfd). a three dimensional, multi-phase simulations with solids transport and removal included is used, and reflected the state of the art in settling modeling. computational fluid dynamics simulations are employed to assess the effect of adding a vertical baffle at the feed section of a full-scale sedimentation tank for the improvement of solids settling in potable water treatment. special attention was paid to the inlet baffle in the model setup. apparently, there is a good agreement between measured and predicted values. results show, the overall solids removal efficiency increased when using the baffle from 50 to 90.5% leading to a reduction of the effluent solids concentration of approximately 86%. keywords circular settling tank, computational fluid dynamics (cfd), residence time distribution (rtd), modeling, simulation تحسین أداء محطات معالجة میاه الشرب في العراق باستخدام نموذج دینامیكا السوائل الحسابیة الخالصة تھ دف ھ ذه الدراس ة إل ى تح سین أداء محط ات معالج ة می اه ال شرب ف ي الع راق و ذل ك بتح سین أداء أح واض الترس یب ف ي محط ة تمت نمذجة أحواض الترسیب . التي تعمل بشكل سیئ أي أن كفاءة المعالجة قلیلة والجزائر لمعالجة میاه الشرب في مدینة الدیوانیة ان النم وذج الریاض ي ال ذي ط ور ھ و نم وذج . عن طریق تط ویر نم وذج دینامیك ا ال سوائل الح سابیة و الخ اص ب أحواض الترس یب د ال صلبة ف ي الح وض و ت ضمن ح ساب كف اءة و ح ساب تركی ز الم وا , و تضمن العالقة ب ین الم واد ال صلبة و ال سائلة , ثالثي األبعاد في ھذه الدراسة تم دراسة تغیر ط ول و ش كل م صدات دخ ول المی اه ال ى ح وض الترس یب و م دى تأثیرھ ا عل ى . أحواض الترسیب وت م مقارن ة النم وذج الریاض ي م ع القیاس ات الحقلی ة لغ رض . تحسین كفاءة األح واض باس تخدام نم وذج دینامیك ا ال سوائل الح سابیة وم ن النت ائج الت ي ت م . معرف ة م دى دق ة النم وذج ووج د ان ھن اك تط ابق كبی ر و م ریح ب ین النم وذج الریاض ي و القیاس ات الحقلی ة و ان تركی ز % 90.5ال ى % 50الحصول علیھا في ھذه الدراسة ان كفاءة أحواض الترسیب ف ي معالج ة می اه ال شرب ق د ازداد م ن %.86یب قلت بنسبة المواد الصلبة الخارجة من حوض الترس dr.abbas a. al-jeebory college of engineering al-qadissiyia university dr. josef kris college of civil engineering slovak university of technology dr.ali h. ghawi college of engineering al-qadissiyia university علي ھادي غاوي. د جامعة القادسیة– كلیة الھندسة جوزیف كرش.د الجامعة التكنولوجیة سلوفاكیا كلیة الھندسة عباس علیوي الجبوري. د جامعة القادسیة–كلیة الھندسة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 2 nomenclatures symbol f description volume force term (n/m3) which is zero in both the x and y directions. u average flow velocity vector (m/s) p average pressure (pa) η dynamic viscosity (pa·s) ρ density (kg/m3) t time (s) cμ model constant k turbulent kinetic energy (m2/s2) ε dissipation of turbulent energy (m2/s3) c concentration of solids (mg/l) us settling velocity (m/s) σc schmidt number (0.7) νt turbulent viscosity uso reference settling velocity (m/s) rh , rp induce the domination of the first and the second term for the falling and the rising part cns nonsettleable concentration (mg/l) cd drag coefficient ρ fluid density (kg/m3) vt blade-to-fluid relative velocity (m/s) a scraper displacement area (m2) gb, gk bouncy and kinetic energy effect cfd computational fluid dynamics rtd residence time distribution ss suspended solids ts total solids introduction the capital infrastructure for water treatment will have to be increased considerably in the immediate future. it is important that new and existing plants are designed to operate as efficiently as possible. the increased activity in this sector will put pressure on experienced designers. one way to promote efficient design and to de-bottleneck existing equipment is to use modern computer techniques. design of sedimentation tanks for water treatment processes are often based on the surface overflow rate of the tank. this design variable is predicated on the assumption of uniform unidirectional flow through the tank. dick (1982), ghawi and kris (2007 a), and ghawi and kris (2007 b) though, showed that many full-scale sedimentation tanks do not follow ideal flow behavior because suspended solids removal in a sedimentation tank was often not a function of the overflow rate. because of uncertainties in the hydrodynamics of sedimentation tanks, designers typically use safety factors to account for this nonideal flow behavior (abdel-gawad and mccorquodale, 1984). recently, computational fluid dynamics (cfd) software has become easy to use, fast and userfriendly. this new generation software offers an inexpensive means of testing and optimizing hydraulic operation of both existing constructions and those under design. the aim of this study was originally stated as to improve the operation and performance al-gazaer water treatment plants by improving circular sedimentation tanks of al-gazaer water treatment plants in al-dewanyia city in iraq which have been identified as operating poorly, which is achieved by predicting the existing flow distribution settling velocity of the sedimentation tanks al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 3 using computational fluid dynamics (cfd) techniques. fluent 6.3 was used for the case study of the effect of adding a feed flow control baffle on the efficiency of solids removal. material and method a full-scale circular sedimentation tank was investigated, similar to that used in the potable water treatment plant of al-dewanyia city. the plant receives raw water from of al-dewanyia river and its capacity is around 2000 m3/hr. the employed processes include, flash mixer, coagulation– flocculation, sedimentation (4 sedimentation tanks), rapid sand filtration, and chlorination (figure 1). the sedimentation tank, with a volume of 1030 m3, is centre-fed with a peripheral weir. the bottom floors have a steep slope of 12◦ and a blade scraper pushes the sludge towards a central conical sludge hopper. two tank configurations have been considered, one with only a small vertical baffle to guide the feed of the tank henceforth referred to as standard tank (figure 2a). and another where the small baffle is extended by an inclined and a second vertical section, altogether meant to guide the fluid significantly deeper inside the tank, henceforth referred to as modified tank (figure 2b). all the tanks had an inlet perforated baffle and an effluent v-notch weir. table 1 shows the settling tanks data. table 2 shows the physical and hydraulic data during study periods. influent and effluent samples were collected at different operating periods. the liquid temperature ranged between 23-29 °c during the experiment. the samples were analyzed according to procedures outlined in “standard methods for the examination of water” , 17th edition, apha, (1989) to determine the following parameters: suspended solids (ss), and total solids (ts) (floc concentration) methodology 1. cfd modelling several computer software programs have been developed for computational fluid dynamic (cfd) modelling. fluent 6.3 and the 3d k-ε turbulence model in the environmental engineering module was used. during this study hydraulic cfd modelling began with the definition of settling tank geometry. fluid characteristics and boundary conditions were defined. the momentum balance including the turbulence model and continuity equations were then solved numerically for the tank using the finite volume method. finally, the obtained solution was post-processed to be properly visualised. common mathematical hydraulic model equations used for cfd modelling include the momentum balances for a non-compressible viscous media and the continuity equation (wilcox, 1998). ftuukc t u puu =+∇+∇         +∇− ∂ ∂ ∇+∇           .))(.( 2 ρ εµ ρµρ (1) 0. =∇ u (2) in the settling model an additional scalar equation was added to include the concentration of the solids. this convection-diffusion equation is as follows:         = + + ix c ixix csuu t c c tv ∂ ∂ σ∂ ∂ρ ∂ ∂ρ ∂ ∂ ρ )( (3) the settling velocity was modeled using the exponential settling function of takács 1991, this expression being introduced in the resolution of the concentration equation. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 4 )](exp[)](exp[ 00 nspsnshss ucrxuucrxuu −−−−−= (4) the standard k-ε eddy-viscosity model is used to account for turbulent effects. the turbulent viscosity is defined as function of the turbulent kinetic energy k and its dissipation rate ε by the equation (wilcox, 1998): ε ρµ µ 2k ct = (5) the distributions of k and ε were determined from the following transport equations: ksmybgkg ix k jx iku ix k t k k t +−−+++=+         ρε ∂ ∂ σ µ ∂ ∂ρ ∂ ∂ ∂ ρ∂ µ )()( (6) ε ε ρε ε ∂ ε∂ σ µ ∂ ∂ρε ∂ ∂ ∂ ρε∂ ε µ s k cbgscckgkk c ixjx iu ix k t t +−+++=+         2 2)()()( (7) the model constants (cμ, cε1, cε2, σk, σε)  in the above equations have been determined from experimental data and are set to standard parameters (wilcox, 1998): cμ = 0.09, cε1 = 0.1256, cε2 = 1.92, σk = 0.9, σε = 1.3 gb describes the influence of buoyancy effects and is defined as a function of the suspended solids concentration gradient: x cv g x cv gg c t wp wp c t b ∂ ∂− = ∂ ∂ = σρρ ρρ σ β (8) the concentration gradient, which reaches maximum values at the interface between the clear fluid and the sludge blanket, hinders turbulence. the source term gb introduced in turbulence equation addresses this matter. the value of cε2, usually reported as constant, varies with the ratio of gravity direction parallel flow velocity with respect to perpendicular flow velocity (wilcox, 1998): u v csc tanh= (9) the later expression yields values close to unity for unstable areas, and tends towards zero for stratified sedimentation. a boussinesq-type approach also implies that the effect of sludge gravity is introduced implicitly as a function of suspended solids concentration. its implementation in the momentum equations is carried out by means of source terms: p wp wp gcg ρ ρρ ρρ − =− )( (10) the dependence of viscosity on concentration is empirically inputted at different concentration ranges. the effect of the scraper blades has been usually either neglected or introduced as uniform constant sources, especially in the modeling of circular sedimentation tank. however, due to the significance of the scraper system for a circular sedimentation tank, an additional sub-model is incorporated to better model the effects of solids transport. the conveying force exerted on the fluid is approximated as a function of fluid velocity including a flow regime dependent drag coefficient: al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 5 2 2 1 rdd avcf ρ= (11) 2. full-scale tracer test tracer tests were performed using pulse addition of lithium chloride (licl). trace concentrations extracted from the outlet can be plotted against time; this is refer to as residence time distribution curve (rtd). a mass of 10.0 kg licl was dissolved in water and diluted to form a 25 liter brine. the brine was poured into a 50 m long hose. by using pressurized wash-water, the tracer was injected into the inlet of the first tank, all within a few seconds. approximately 150 samples (100 ml each) were taken during the tracer tests. samples were taken at the outlet of the settling tank. the samples were allowed to settle and the supernatant was filtered (1.2 μm membrane filter, titan 2 hplc filter orange 30 mm) in order to reduce interference of solids. the lithium concentrations of the samples were measured using a flame photometer (eppendorf elex 3631). this was calibrated on site, using final effluent as dilutant when creating a lithium standard curve. 3. simulation and boundary condition to limit computational power requirements, the circular settling tank was modeled in 3d. the major assumption in the development of the model is that the flow field is the same for all angular positions; therefore, a 2d geometry can be used to properly simulate the general features of the hydrodynamic processes in the tank. as a first step, a mesh was generated across the sedimentation tank. a grid dependency study was performed to eliminate errors due to the coarseness of the grid and also to determine the best compromise between simulation accuracy, numerical stability, convergence, and computational time. in addition, the mesh density was chosen such that the grid was finest where velocity gradients are expected to be largest. the selected grid was comprised of 117,324 quadrilateral elements. two other grids (one finer with 200,850 elements and one coarser with 9160 elements) were also used to determine the effect of the overall grid resolution on predictions. while the predictions obtained using the coarse grid were found to be different from those resulting from the selected one, the difference between the predictions made by the selected and fine grids were insignificant. as a result, the solutions from the grid of 117,324 quadrilateral elements were considered to be grid independent. the segregated solution algorithm was selected. the settling tang k–ε turbulence model is used to account for turbulence, since this model is meant to describe better low reynolds numbers flows such as the one inside our sedimentation tank (wilcox, 1998). the used discretisation schemes were the simple for the pressure, the piso for the pressure–velocity coupling and the second order upwind for the momentum, the turbulence energy and the specific dissipation. adams and rodi (1990) pointed out that for real settling tanks the walls can be considered as being smooth due the prevailing low velocities and the correspondingly large viscous layer. consequently, the standard wall functions as proposed by launder and spalding (1974) were used. the water free surface was modeled as a fixed surface; this plane of symmetry was characterized by zero normal gradients for all variables. as a first step, the fluid mechanics problem was solved in the absence of particles to find the steady state flow field. the converged solution was defined as the solution for which the normalized residual for all variables was less than 10−6. in addition, the convergence was checked from the outflow rate calculated at each iteration of the run. the convergence was achieved when the flow rate calculated to exit the tank no longer changed. the inlet was specified as a plug flow of water at 0.075m.s−1, whereas the inlet turbulence intensity was set at 4.5%. the outlet was specified as a constant pressure outlet with a turbulence intensity of 6.0%. the water flow rate was 0.25 m3 s−1. based on this rate, the inlet mass flow rate of particles was estimated as 0.11 kg s−1 using a measured solids concentration of 200 mg. l−1, whereas the primary particle density was 1062 kg.m−3. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 6 results and discussion as far as the cfd model validity is concerned, figure 3 presents a comparison between data experimental measurment and the simulated values of the li distribution in the effluent of the standard tank. apparently, there is a good agreement between measured and predicted values. the removal efficiency in settling tanks depends on the physical characteristics of the suspended solids as well as on the flow field and the mixing regime in the tank. therefore the determination of flow and mixing characteristics is essential for the prediction of the tank efficiency. figure 4 presents the predicted streamlines for the standard and the modified tank. the influent, after impinging on the standard flow control baffle at point a, is deflected downwards to the tank bottom. the flow splits at point b on the bottom of the tank, producing a recirculation eddy at c. generally, the flow pattern is characterized by a large recirculation region spanning a large part of the tank from top to bottom. three smaller recirculation regions are also found; two at the top of the tank near the entry and exit points of the liquid stream and one at the bottom right-hand side of the tank just above the cavity where the sludge gathers before leaving the tank. these regions have a substantial impact on the hydrodynamics and the efficiency of the sedimentation tank. the same behavior was observed by stamou (1991) in his flow velocity predictions in a settling tank using a curvature-modified k–ε model. the above-mentioned observations are in agreement with findings of zhou and mccorquodale (1992), who studied numerically the velocity and solids distribution in a clarifier. according to another numerical work (deininger et al, 1998), in secondary clarifiers there is a circular current showing: (1) forward flow velocities in the zone close to the tank bottom, (2) backward flow velocities in the upper zone of the tank, (3) higher forward flow velocities in the inlet than in the rim region, (4) higher backward flow velocities in the inlet than in the outlet region, (5) vertical currents downwards to the tank bottom in the inlet region, and (6) vertical currents upwards to the water level in the outlet region. for the case of secondary clarifiers with highsuspended solids concentration, a density current exists due to a higher density of the incoming suspension. this current sinks toward the sludge blanket right after leaving the inlet structure and flows towards the tank rim. as a result, backward velocities are induced in the upper water zone following the continuity equation. a number of researchers have observed the solids-cascading phenomenon in the clarification of concentrated activated sludge in either theoretical simulations or experimental works. as it can be concluded comparing figure 4(a), the particles do not affect the flow field. this observation is attributed to the particle loading in our sedimentation tank and is similar to that made by kim et al. (2005), who worked in a secondary clarifier with a neutral density influent flow. on the contrary, in the case of high inlet fluid density (high solids concentration) combined with a low fluid velocity, the horizontal inlet flow does not even reach the flow control baffle, but plunges down toward the tank bottom as a density waterfall due to the low froude number. in the modified tank, the flow split point b moves more to the right of the tank bottom compared to the position in the standard tank and the recirculation zone above the sludge corner is now very small. it appears that the extended baffle does not affect the flow pattern or the particle trajectories throughout the tank or at the exit. neither does it affect the particle settling patterns on the bottom of the tank. the difference is mostly restricted at the entrance section and near the bottom rim of the tank, so that the upward flow in the downstream zone is only slightly different. in general, the extended baffle appears to provide better influent mixing and isolation between the tank influent and effluent than that in the original tank design, thus significantly enhancing sedimentation. in addition, it allows a better utilization of the full tank depth than in the standard design that leads to better separation between the influent and effluent along the vertical direction. studies by zhou and mccorquodale (1992) revealed the importance of a baffle in dissipating the kinetic energy of the incoming flow and reducing short-circuiting and indicated that the location of the baffle has a pronounced effect on the nature of the flow. the percents presented in table 3 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 7 result in an overall settling efficiency of 50 and 90.5% for the standard and the modified tank, respectively. the overall solids removal efficiency increased when using the baffle from 50 to 90.5 % leading to a reduction of the effluent solids concentration of approximately 86%. the increase in the overall effectiveness seems small it corresponds to an estimated reduction in the solids exiting the tank of approximately 610 kg d-1 or to a reduction of about 86% of the solids that exit the tank. these values are greater than those reported by other researchers. huggins et al. (2005), who tested a number of potential raceway design modifications noticed that by adding a baffle the overall percent solids removal efficiency increased from 81.8 to 91.1% resulting in a reduction of the effluent solids of approximately 51%. crosby (1984) used an additional baffle at mid-radius extending from the floor upwards to mid-depth and observed a reduction of 38% in effluent concentration. according to huggins et al. (2005), the particle settling velocity has a significant impact on the settling efficiency for a given raceway design. these authors argued that an important consideration in trying to improve the settling of particles is to reduce the mass fraction of solids with settling velocities below 0.01m.s−1.however, since influent solids load is usually uncontrollable one should focus instead on the design of a proper baffle, which will improve solids settling by forcing them to reach fast the bottom of the tank. figure 5 shows contours of velocity for the standard and the modified tank. the effect of modifications are also displayed in figures 6 and 7 that show flocs concentration along the tank bottom. in figures 6 and 7 the zero position of the horizontal axis is set at the righthand end of the tank bottom. clearly, the modified tank allows flocs to settle at much short distances from the right-hand corner of the tank. this diminishes the overall settling efficiency of the tank. on the whole, the simulation results demonstrate quantitatively the drastic effect of particle velocity on sedimentation effectiveness. higher settling velocities lead to more effective sedimentation. however, even small differences in particle settling velocity can cause large changes in the percent of settled particles conclusions cfd could be used in reviewing settling tank design or performance and the results give valuable insight into how the tanks are working. also cfd could be use to evaluate settling tank designs where the tanks are not functioning properly. overall, the following conclusions can be taken in relation to this study: v cfd modeling is successfully used to evaluate the performance of a settling tank and water treatment plant. v high solid removal efficiency were achieved. v the results show that an extended baffle forces the solids to move faster towards the bottom of the tank and decreases the inlet recirculation zone, thus yielding significantly enhanced sedimentation. although the increase in the overall effectiveness by this baffle may show only a small change, this actually reflects a reduction of the effluent solids of estimated around 86%. acknowledgements the authors wish to thank the al-gazaer water treatment plant staff for accessing to the required data. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 8 references abdel-gawad, s. m. & mccorquodale, j. a. hydrodynamics of circular primary clarifiers. canadian j. civil engr. ,11, 299-307, (1984). adams e.w., & rodi w., modelling flow and mixing in sedimentation tanks, j. hydr. eng. 116 (1990) 895–913. apha, “standard methods for the examination of water and wastewater,” 17th edition, american public health association, washington, d.c. (1989). crosby r.m., hydraulic characteristics of activated sludge-secondary clarifiers, epa 600/2-84-131, ntis no. pb-84-229665, u.s. epa, municipal and environmental research laboratories, cincinnatti, oh, (1984). huggins d.l., piedrahita r.h., & rumsey t., use of computational fluid dynamics (cfd) for aquaculture raceway design to increase settling effectiveness, aquacult. eng. 33 (2005) 167–180. deininger a., holthausen e., & wilderer p.a. velocity and solids distribution in circular secondary clarifiers: full scale measurements and numerical modelling, water res. 32 (1998) 2951–2958. dick, r. i. sedimentation since camp, j society of civil engrs, 68, 199-235, (1982). ghawi a. hadi & jozef kris. design and optimization of sedimentation tank in slovakia with cfd modelling. 10th international symposium on water management and hydraulic engineering 2007 with special emphasis on the impact of hydraulic engineering construction on the environment 4 – 9 september 2007. šibenik , croatia. (2007a). ghawi a. hadi, & jozef kris. a numerical model of flow in sedimentation tanks in slovakia” third international phd symposium in engineering 25-26 october 2007, hungary university of pollack mihály faculty of engineering pécs, hungary. (2007b). kim h.s., shin m.s., jang d.s., jung s.h., & j.h. jin, study of flow characteristics in a secondary clarifier by numerical simulation and radioisotope tracer technique, appl. radiat. isotopes 63 (2005) 519–526. launder b.e., & spalding d.b., the numerical computation of turbulent flows, comp. meth. appl. mech. eng. 3 (1974) 269–289. stamou a.i., on the prediction of flow and mixing in settling tanks using a curvature modified k-ε model, appl. math. modelling 15 (1991) 351-358. takács i., patry g.g. & nolasco d. (1991). a dynamic model of the clarification-thickening process. wat. res., 25(10), pp. 1263-1271. wilcox d.c., turbulence modeling for cfd, dcw industries, inc., la canada, california, (1998). zhou s., & mccorquodale j.a., influence of skirt radius on performance of circular clarifiers with density stratification, int. j. numer. meth. fluids 14 (1992) 9-19. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 9 table 1. settling tanks data. tank parameter value tank diameter (m) 18 m depth of inlet (m) 5.6 m tank depth (m) 4.0 m no. of tanks 4 table 2. physical and hydraulic data during study periods. tank parameter value average flow rate 500 m3/hr sludge pumping rate 5 l/s average inflow temperature 6oc in winter and 29oc in summer inflow suspended solids 25-75 mg/l detention time 3.5 hr cmin 0.17 mg/l table 3. performance data for modelled settling tank efficiency of settling tanks influent conc.= 40 mg/l influent conc.= 50 mg/l influent conc.= 60 mg/l influent conc.= 75 mg/l predicted average effluent concentration existing tank (50 %) (from measurement) 20 25 30 37.5 modified tank (90.5 %) (from cfd) 3.8 4.7 5.7 7.1 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 10 figure 1. layout of water treatment plant of al-gazaer in al-dewanyia city. a) the standard tank b) the modified tank figure 2. schematic representation of the standard (a) and the modified (b) simulated sedimentation tank. ` treatment work distribution work l. l. p cl2 r.s.f . g.t h. l. p e.t. -l.l.p.: low lift pump -f.m.: flash mixing & distribution tank -r.s.f.: rapid sand filter -cl2: dosing of chlorine -g.t.: ground tank -h.l.p.: high lift pump -e.t.: elevated tank collection work al dewanyia river f.m. coagulant sedimentation cl2 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 11 figure 3. li tracer characteristic of the standard sedimentation tank (concentration –time relationship). a) standard tank b) modified tank. figure 4. evaluated streamlines for sedimentation tank from cfd result. (a) standard tank, and (b) modified tank. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 12 figure 5. velocity contours (m s-1) for sedimentation tank for (a,b) the standard and (c,d) the modified tank for different solid concentration from (25 (a,b)-75 (c,d) mg/l) a) b) figure 6. flocs concentration (kg m-3) along the tank bottom for the standard (a) and the modified tank (b) for inlet concentration 40 mg/l. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 13 a) b) figure 7. flocs concentration (kg. m-3) along the tank bottom for the standard (a) and the modified tank (b) for inlet concentration 75 mg/l al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥ numerical simulation of melting solidification process in an alloy metal with a square section mr.hameed k. al naffiey babylon university – college of engineering department of mechanical engineering abstract this study is used to construct a mathematical model to analyze melting solidification process considering condition phenomena to an alloy metal in a square section. the aim of the present study, know the time that the metal is solidification in the mold to know the time that open the mold. after the fluid inters the mold as a liquid, the heat is transferred by conduction and convection, including de thermal phase change phenomena. the mathematical model consists of square section which has length l and [a*b] dimensions. the metal enters the mold from upper end and go to fill all the mold use explicit technique is used to calculate the temperature during the mold and use the thermal phase phenomena from liquid to solid. in this study used finite difference method to solve the mathematical model also used computer program fortran 90 to solve this model. the result represented by golden software surfer 8. also this study may be used in refrigeration of water and studying solidification from the water to ice. keywords /heat transfer, numerical, conduction, convection, alloy, molds, and solidification. في الحاصلة المعدنیة ةسباكالفي الحاصل یل العددي لعملیة التجمدمثالت قالب مربع المقطع مدرس مساعد/ د حمید كاظم حمزة السی قسم المیكانیك/كلیة الهندسة/جامعة بابل : الخالصة تحلیnل مربnع حیnث تnم ذي مقطnع في ھذة الدراسة تم عمل نموذج ریاضي لعملیة التجمnد الحاصnلة فnي قالnب بنوعیnnة الحمnnل النمnnوذج تحلnnیال عnnددیا وبتnnالي دراسnnة إلیnnة التجمnnد الحاصnnلة فیnnھ المصnnحوبة بانتقnnال الحnnرارة الھدف من ھذه الدراسة ھو معرفة الnزمن أالزم لتجمnد المnائع داخnل فnراغ القالnب وبالتnالي تحدیnد . والتوصیل al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٧٦ المودیل الریاضي یتضمن قالب .الزمن الالزم لفتح القالب ویتم ذلك بدراسة انتقال الحرارة كدالة لزمن التجمد لى القالب من األعلnى ثnم ینتقnل تnدریجیا إلnى جمیnع أجnزاء المائع یدخل بشكل سائل إ.lوطولة [a*b] أبعادة القالب وبمرور الزمن یتحول إلى الحالة الصلبة بسبب الفقدان الحراري الحاصnل بنوعیnة الحمnل والتوصnیل وكnnذلك اسnnتخدم ، فnnي ھذةالدراسnnة تnnم اسnnتخدام طریقnnة الفروقnnات المحnnددة لحnnل المودیnnل ریاضnnي المسnnتخدم. goldenالستخراج النتnائج التnي تnم تمثیلھnا الحقnا باسnتخدام برنnامج fortran 90برنامج حاسوبي بلغة software surfer 8 .ثلجnناعة الnل صnي معامnائع فnوع المnر نnة بتغییnكذلك ممكن االستفادة من ھذه الدراس . ودراسة آلیة التجمد 2-nomenclature: cp: specific heat capacity; j/kg k fο: fourier number; k: thermal conductivity; w/m2 k l: length; m l : latent heat capacity ; j/kg k m: subregion number; t: temperature; k q•: heat generation rate per volume; w/m q': heat flux; w/m2 t: time; sec x: distance ;m subscript m: mold c: casting superscript n:time denoted greek symbols r: density of material; kg/m3 partition ratio :γ dt: time interval dx: distance interval introduction the solidification rate of alloys is important processing variable, and solidification rate relates directly to the coarseness of dendritic structures and hence controls the al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٧٧ spacing and distribution of micro heterogeneities, such as dendritic ,second phases, inclusions and micro porosity microsegregation,by d.r poirier 1993 . this research presents a study about solidification of alloy of metals that is known in the literature as solid – liquid phase change problem. from this study, the interfacial heat transfer coefficient has been found to depend on many factors including the presence and thickness of surface. mold material applied pressure, liquid alloy surface tension by carslaw , h.s. 1959 . the effect, of the direction of gravity in relation to the interface has been examined by investigation with the mold place on the bottom. an a temperature distribution of heat transfer during liquid alloy solidification in a casting mold depends on determination of the boundary conditions during the solidification, properties of the mold, properties of the casting alloy by sully ljd.1976.the heat transfer during the mold caused phase change, and then transfer by conduction and convection to wall, the thickness of the wall may be design according to the alloys process and metals by welty(1997).the mold that used in this study has square cross section see fig.1. mathematical model the mathematical analysis is based on the following assumptions: 1. one dimension and unsteady state heat transfer model. 2. all the physical properties are assumed to be constant. 3. the fluid is considered incompressible with constant properties. heat flow in the chill. the amount of heat that escapes of the chill is very important to determine the temperature distribution in the ingot. the heat flow through the casting can be approximated as a one dimension heat transfer problem .unsteady state (transient) condition heat transfer in a one dimension body is given by yunus, a.1998. (1)0tl,x0 t t)t(x, α 1 x t)t(x, 2 2 >££ ¶ ¶ = ¶ ¶ where t is the temperature, t is the time and x is the cartesian coordinate. the term is the thermal diffusivity of the conduction material which is given by )2( pcρ k α = al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٧٨ where k the thermal conductivity, ρ is the density and cp is the specific heat capacity. 2-heat flow in the casting the governing equation that describes the casting heat flow for solidifying metals is given by )3( t t)(x, cρq x t)t(x, k 2 2 ¶ ¶ =+ ¶ ¶ · t p the term q• represents heat source term, to account for the change of phase from liquid to solid in a binary alloy, each computation cell contains a fraction of solid (fs) and fraction of liquid(fl) ,where the sum of fractions must equal unity. by m.rapaaz,(1988). )4( t f ρlq s ¶ ¶ =· where l is the latent heat of fusion and fl term is determined by i.imafoku (1983). )5( sl s l tt tt f = this equation is based on the assumption freezing. (6) )tγ)(t-(1 )t(tγmc f m m1 l -= o the term t f s ¶ ¶ , can be related to temperature from )7( t t t f t f ss ¶ ¶ ¶ ¶ = ¶ ¶ substitution of eq. (7), in eq. (4), gives (8) t t t f ρlq s ¶ ¶ ¶ ¶ =· the latent heat is added to the energy by using an effective specific heat .it has been found that method tends to be inefficient. )9()( t f lcc lp ¶ ¶ += tp substitution of eq. (8), in eq.(1), gives )10( t t cρ t t t f ρl x t k p s 2 2 ¶ ¶ = ¶ ¶ ¶ ¶ + ¶ ¶ this equation can be rearranged to give al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٧٩ )11( t t t f lcρ x t k s 2 2 ¶ ¶ ÷ ø ö ç è æ ¶ ¶ -= ¶ ¶ p then eq.(11), can be written as )12( t t)t(x, k cρ x t)t(x, p 2 2 ¶ ¶ = ¶ ¶ 3-finite difference formulation finite difference methods are use to solve eq.12, equation12 represent temperature of distribution in the mold. now construct mesh along the mold as shown in fig.(2) .in the finite difference analysis of one-dimension conduction of element ,the central finite difference are used for grid as shown , by petrovetc, z.(1996). however, these solutions can be generated for an assortment of simple geometries and boundary condition, and they are well documented in the literature. on the other hand, analytical solutions to transient problems are restricted to simple geometries and boundary conditions. in the present work, this problem has been approached in one dimensional geometry for a region with a finite dimension l shown in fig. (2) as follows: the region (0 ≤ x ≤ l) is divided into m equal size meshes. )13( m l x =d m subscripts are used to designate the x location of the discrete node points in fig.2. besides being discredited in space, the problem must also be discredited in time. the integer n is introduced for this purpose (14)δxnt = the finite difference approximation to the time derivatives of t, and the time derivatives in left side of eq.(12) is expressed as 15( δt tt t t nm 1n m m = ¶ ¶ + the superscript n is used to denote the dependence of t , and the time derivative is expressed in terms of the difference in temperature associated with the new (n+1) and the previous (n) time steps. eq.(12) solved using an explicit finite deference methods for the chill and casting by )16( δt tt α 1 )(δ t2tt nm 1n m 2 n 1m n m n 1m -= ++-+ x this can be rearranged to give, al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٨٠ )17()t(tf)2f(1tt n 1m n 1m n m 1n m -+ + ++-= where f is a finite difference form of the fourier number, which is given by )18( 2δx αδt f = the term dx and dt in this study, refer to the space and time increments used in the calculation. in this work, the differential elements are select as dx=2 mm and dt = 0.5 sec for both casting and the chill, complying f ≤ 0.5 . 4-the boundary conditions from the symmetrical of the system, the boundary conditions are )21( (20) (19 tmt(x,0)0,tat )t c hp(t dx dt k.a.axat ))t c hp(t dx dt k.a.0xat == ¥-=÷ ø ö ç è æ -= ¥-=÷ ø ö ç è æ -= equation17 represent temperature distribution along casting after construct computer program to solve this equation and depend on boundary condition also we needed gauss elimination method to solve this equation. 5. result and discussion. fig.(3) represented the relation between the heat flux and the time of remaining the metal in the mold. we conclude that when the time increases the heat flux decrease for steal chill or cupper chill because the heat is transfer to the surrounding increase. the higher curve for cupper chill and the lower represent the steal chill. fig 4 fig.(5), and fig6 represented temperature distribution along cross section of mold at different time .from these figures conclude that the temperature decreases with time and as is very high in the center of mold and decreases towards the surface of mold because the heat transfer to surrounding. fig.(4) represents the temperature distribution at time 200 sec .the line in this fig. represent the temperature distribution. fig.(5) represents the temperature distribution at time 500 sec .the line in this fig. represent the temperature distribution. fig.(6) represents the temperature distribution at time 700 sec .the line in this fig. represent the temperature distribution. from these figures conclude when the time increase the metal convert from liquid to solid and solidification accurse and from these figure we needed time more than 700 sec to open the mold. fig.(7) represent temperature distribution at the different al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٨١ location along the mold from this figure conclude the temperature decrease as the time increase from the center of the mold to the wall. and this time change as a function to fluid and the dimension of the mold also the metal of chill. this result compact with the theoretical result by c.p hong,(1990). as shown in fig. (8). 6. conclusion. 1the difference of the thermal properties between liquid and solid gives influence to change the whole solidification behavior. 2the heat transfer from the corner of the mold is very high because the heat is transfer to surrounding through two walls. 3the time that used to open the mold depend on the temperature of metal at inters and the properties of metal also the location of raiser. .7. references · carslaw , h.s. and jaeger , j,c. " condution of heat in solids ",secondedition ,oxford university press , london , 1959 . · c.p.hong,t. umeda,and y.kimura, "numerical models for casting solidification "metal transactions b, vol.15b, march 1990, p.91. · d.r.poirier and e.j.poirier ,"heat transfer fundamentals for metal casting" second edition ,united states of america,1994 · i.imafoku and chijiiwa ,"a mathmatica model for shrinkage cavity prediction in steal casting",afs transaction,91,pp.527-540 (1983) · m.rappaz,d.m stefanescu, "modeling of microstructure evolution". metals hand book," asm,(1988) · sully ljd.the thermal interface between castings and chill molds .afs trans 1976; 84:735-44. · petrovetc, z. stupar, s .“cfd one, computational fluid dynamics one”, mechanical engineering faculty, belgrade 1996. · welty, wicks, wilson “fundamentals of momentum, heat, and mass transfer, 3rd edition”, john wiley & sons, p.252-295. ,(1997) · yunus, a. cengel, “heat transfer a practical approach”, mc-graw hill, inc., 1998. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٨٢ . a l b section fig.1: the dimension of the mold 0 x = 0)( m x = l)( m-1 m m+1 dx dx fig.2. finite difference node points in onedimension conduction. 50 150 250 3500 100 200 300 400 time(sec) 500 1500 2500 0 1000 2000 3000 h ea t fl u x( k w /m 2) steel chill cupper chill al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٨٣ 0 10 20 30 40 50 60 70 b(mm) 0 10 20 30 40 50 60 70 a (m m ) 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70 a (m m ) fig.3: heat flux between casting and chill as a function of time. fig.4a fig.4b al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٨٤ a b fig.5: temperature distribution at time 500 sec in mold 0 10 20 30 40 50 60 70 b(mm) 0 10 20 30 40 50 60 70 a (m m ) fig.6: temperature distribution at time 700 sec in mold b(mm) fig.6a fig.6b 0 200 400 600 800 680 720 760 800 840 t em p er at u re (k ) at x=10 mm at x=20mm at x=35mm al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٨٥ fig.8: temperature distribution compare with result by c.p hong,(1990). 100 300 500 7000 200 400 600 800 time(sec) 740 780 820 720 760 800 840 t em p er at u re (k ) at center at x=200 mm at center at x=200 mm fig.7: temperature distribution at several distances in mold 15-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 influence of styrene butadiene rubber on the mechanical properties of asphalt concrete mixtures dr. amjad h. albayati transportation eng./ baghdad univ. email: sirtransportation@yahoo.com asst. lect. hussein kariem mohammed ministry of higher education and scientific research email: hkm34e @yahoo.com abstract asphalt binder, is a thermoplastic liquid, which behaves as an elastic solid at low service temperatures or during rapid loading. at high temperature or slow loading, it behaves as a viscous liquid. this classical dichotomy creates a need to improve the performance of an asphalt binder to minimize the stress cracking that occurs at low temperatures (fatigue) and the plastic deformation at high temperatures (rutting). use of polymer-modified asphalt binder is one of the solutions to meet the required performance standards for the pavements of today. it appears to be a logical, practical, and economical approach. in this research an investigation was made to evaluate the influence of asphalt cement modifier on the mechanical properties of asphalt concrete mixtures. the conventional asphalt cement of penetration grade 40-50 was used within this work, modified with styrene butadiene rubber (sbr) at five different modification levels namely 0%, 1%, 3%, 5% and 7% by weight of asphalt cement. asphalt concrete mixes were prepared at selected optimum asphalt content (4.7%) and then tested to evaluate their mechanical properties which include resilient modulus, permanent deformation and fatigue characteristics in addition to marshall properties. the mechanical properties have been evaluated using uniaxial repeated loading and repeated flexural beam tests. from the experimental results, it can be concluded that the mixes modified with sbr polymer have shown an improved fatigue and permanent deformation characteristics as well as superior elastic properties as a characterized via resilient modulus. the use of 3 percent sbr has added to local knowledge the ability to produce more durable asphalt concrete mixtures with better serviceability. keywords: asphalt concrete, styrene butadiene rubber (sbr), fatigue, permanent deformation, resilient modulus. sbr ١. / / / | ٢-. . / / : al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 .یعت .بینما مثل،فيالستمما للتقلیل مما هي. sbr . sbr)٥٧، ٣، ١، ٠ %(، ، )٤.٧٠ ( ، .sbr .٣ % sbr . 1-introduction it is important to understand the mechanism of complex behaviors of asphalt concrete mixtures in the field of improving the pavement mechanical performance. aggregate gradation and asphalt cement are two key factors that influence the engineering properties of asphalt concrete mixtures; essentially the asphalt binder is the component that determines the mix viscous behavior and consists of asphalt cement and modifier. many research works suggest that a specified polymer is a promising modifier to improve the asphalt binder properties and hence to develop the mixture viscoelastic properties. the use of polymer modified bitumen (pmb) to achieve better pavement performance has been studied for a long time. the properties of pmb are dependent on the polymer characteristics and content as well as the bitumen nature. polymer that used to modify bitumen for road applications is divided to two main basic type, plastomers and elastomers. plastomers such as polyvinyl chloride (pvc), ethyl-vinyl-acetate (eva) and ethylene propylene (epdm) are typically used to modify bitumen by forming a tough, rigid, three-dimensional network to resist deformation. elastomers such as styrene butadiene rubber (sbr) and styrene butadiene styrene (sbs) have a characteristically high elastic response and, therefore, resist permanent deformation by stretching and recovering their initial shape, also it exhibit increased tensile strength with elongation and have the ability to recover to the initial condition after an applied load is removed. sbr latex has been widely used as a binder modifier. an engineering brief from 1987 available at the us federal aviation administration website (bates, 1987)(6) describes some of the benefits of sbr modified asphalt in improving the properties of asphalt concrete pavement. low-temperature ductility is improved, viscosity is increased, elastic recovery is improved, adhesive and cohesive properties of the pavement are improved. in view of this, the necessity for the use of sbr to improve the performance of local asphalt concrete performance has been arising. with this purpose in mind, the primary objective of this study is to evaluate the mechanical properties of asphalt concrete mixtures containing sbr polymer based on the following tests, marshall properties (mix al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 design parameters), uniaxial repeated load test ( resilient modulus and permanent deformation) and repeated flexural beam test (fatigue characteristics). 2literature review (xicheng, 1995)(12) investigated the permanent deformation behavior of unmodified asphalt concrete mixtures as compared to the behavior of asphalt concrete mixtures modified with polyethylene. the polyethylene modified mixtures exhibit higher resistance to rutting than the unmodified ones. in addition the layer coefficients of the polyethylene-modified mixtures were 7585% higher than the layer coefficients of the unmodified ones. the dynamic stiffness modulus, fatigue resistance, and creep resistance of the mixtures were evaluated. the results showed that all the polymer-modified mixtures performed better than the unmodified ones. the polyethylene binder-rich mixtures are superior to binder-rich unmodified mixtures in their rutting resistance, immunity to densification, and resistance to fracture. (awanti, 2008)(5) presented the laboratory investigations carried out to determine the various engineering properties such as physical properties of asphalt cement and (polymer modified asphalt binder) pmab with (styrene-butadiene-styrene triblock copolymer) sbs, he concluded that: athe temperature susceptibility of pmab-sbs is lower than asphalt cement. bmarshal stability and flow of pmac mix are higher than compared to ac mix at optimum binder content. cthe static indirect tensile strength values for pmac mixes were higher compared to ac mixes at different temperatures. dmoisture susceptibility of pmac mixes is low when compared to ac mixes. (al-hadidy, 2010)(3) studied the properties of modified asphalt binders and stone mastic asphalt concrete (smac) containing such as asphalt binders and made a comparison with asphalt cement. they used a mechanistic-empirical design approach for estimating the improvement in service life of the pavement or reduction in thickness of smac and base layer for the same service life due to modification the smac. they showed that the performance of sbs-modified smac is slightly better when compared to starch-modified smac. also the pavement consisting of sbs and starchmodified smac as a surface layer is beneficial in reducing the construction materials. (reynaldo, 2005)(9) used both styrene butadiene styrene (sbs) and ground tire rubber (gtr) as a modifier, they found that the sbs-polymer reduced the rate of micro-damage development and consequently increased the number of load repetitions required for crack initiation. this is consistent with the lower m-value determination for the modified mixtures. the normalized resilient deformation prior to crack initiation was about the same for modified or unmodified mixtures because the failure limits (fracture energy, dissipated creep strain energy to failure) were relatively unaffected by the sbs modifier. the relative effect of sbs modifier was increased at higher binder contents temperatures. 3material characterization asphalt cement, aggregate, and filler used in this work have been characterized using routine type of tests and the results were compared with state corporation for roads and bridges specifications (scrb, r/9 2003)(10). one type of electrometric polymer which was styrene butadiene rubber (sbr) has been used as an additive for asphalt cement. a photograph for this additive is shown in figure (1). 3-1 asphalt cement the asphalt cement used in this work is 40-50 penetration grades. it was obtained from the dora refinery, south-west of baghdad. the asphalt properties are shown in table (1). 3-2 aggregate the aggregate used in this work was crushed quartz obtained from amanat baghdad asphalt concrete mix plant located in taji, north of baghdad, its source is al-nibaie quarry. this type of al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 aggregate is widely used in baghdad city for asphaltic mixes. the coarse and fine aggregates used in this work were sieved and recombined in the proper proportions to meet the wearing course gradation as required by scrb specification (scrb, r/9 2003)(10). the aggregate gradation properties are presented in table (2) and gradation curve is shown in figure (2). routine tests were performed on the aggregate to evaluate their physical properties. the results together with the specification limits as set by the scrb are summarized in table (3). tests results show that the chosen aggregate met the scrb specifications. 3-3 filler the filler is non plastic materials that pass sieve no.200 (0.075mm). mineral filler used in this work is limestone dust obtained from ammanat baghdad asphalt concrete mix plant; its source is the lime factory in kerbala governorate. the chemical composition and physical properties of the used filler is presented in table (4). 4experimental work the experimental work was started by the selection of 4.7 percent optimum asphalt content for control mix and used in all other sbr modified mixes to maintain consistency throughout the research. to investigate the effect of sbr on the asphalt cement, asphalt binder (asphalt cement and sbr mixes) were prepared and tested using the conventional binder tests, penetration and softening point. the test results were used in the calculation of penetration index to evaluate the effect of sbr on the temperature susceptibility of asphalt cement. also, asphalt concrete mixes were made using 0, 1, 3, 5 and 7 percent sbr by weight of asphalt cement and tested to evaluate the marshall properties as well as the mechanical properties which include resilient modulus, permanent deformation and fatigue characteristics. the mechanical properties have been evaluated using uniaxial repeated loading and repeated flexural beam tests. 4-1 conventional binder test to investigate the effect of sbr upon the asphalt cement, the penetration as well as softening point tests was conducted according the astm d5 and astm d 36, respectively. in addition, the temperature susceptibility of the modified bitumen samples has been determined in terms of penetration index (pi) using the results obtained from penetration and softening point tests. temperature susceptibility is defined as the change in the consistency parameter as a function of temperature. a classical approach related to pi calculation has been given in the shell bitumen handbook (whiteoak, 1990)(11) as shown with the following equation : 120)(log50 20)(log5001952 25 25 sppen sppen pi (1) where: pen 25 = penetration at 25°c sp= softening point, °c 4-2 marshall properties for each percentage of sbr content, marshall specimens were prepared according to the marshall .2(ai,1981)(2) using 75 blows (scrb, r/9 2003) (10) of the automatic marshall compactor on each side of specimen. the specimens were evaluated for marshall stability, flow value, density, percent air voids (av) and percent voids in mineral aggregate (vma). 4-3 uniaxial repeated loading test the uniaxial repeated loading tests were conducted for cylindrical specimens, 101.6 mm (4 inch) in diameter and 203.2 mm (8 inch) in height, using the pneumatic repeated load system (shown below al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 in fig.(3)). in these tests, repetitive compressive loading with a stress level of 20 psi was applied in the form of rectangular wave with a constant loading frequency of 1 hz (0.1 sec. load duration and 0.9 sec. rest period) and the axial permanent deformation was measured under the different loading repetitions. all the uniaxial repeated loading tests were conducted at 40°c (104°f). the specimen preparation method for this test can be found elsewhere (albayati, 2006)(9). the p h dp p 610 (2) where: pd= axial permanent deformation h= specimen height also, throughout this test the resilient deflection is measured at the load repetition of 50 to 100, and r) are calculated as follows: h rd r 610 (3) r rm (4) where: rd= axial resilient deflection h= specimen height mr= resilient modulus the permanent deformation test results for this study are represented by the linear log-log relationship between the number of load repetitions and the permanent microstrain with the form shown in eq.5 below which is originally suggested by (monismith,1975)(8) and (barksdale,1972)(7). (5) where : p= permanent strain n=number of stress applications a= intercept coefficient b= slope coefficient 4-4 flexural beam fatigue test within this study, third-point flexural fatigue bending test was adopted to evaluate the fatigue performance of asphalt concrete mixtures using the pneumatic repeated load system, this test was performed in stress controlled mode with flexural stress level varying from 5 to 30 psi applied at frequency of 2 hz with 0.1 sec loading and 0.4 sec unloading times and in rectangular waveform shape. all tests were conducted as specified in shrp standards at 20°c (68°f) on beam specimens 76 mm (3 in) x 76 mm (3 in) x 381 mm (15 in) prepared according to the method described in (alkhashab,2009)(4). in the fatigue test, the initial tensile strain of each test has been determined at the 50th repetition by using (eq.6) shown below and the initial strain was plotted versus the number of repetition to failure on log scales, collapse of the beam was defined as failure, the plot can be approximated by a straight line and has the form shown below in (eq. 7). b p an al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 22 43 12 al h est (6) 2 1 )( k tf kn (7) where: = initial tensile strain es =stiffness modulus based on center deflection. h =height of the beam l = length of span between supports. a =distance from support to the load point (l/3) = number of repetitions to failure 1k = fatigue constant, value of nf when = 1 2k = inverse slope of the straight line in the logarithmic relationship 5results and discussion 5-1 effect of sbr on asphalt binder the experimental results for the effect of sbr content on the asphalt binder properties are listed in table (5), from this table the following points can be noticed: a slight decrease in penetration value was obtained with increasing sbr content as shown in fig (4). the reduction in penetration ranged from (48) to (35) for an increment in the sbr content from (0%) to (7%). the modification also reduces temperature susceptibility of the bitumens, as indicated by increased penetration index (pi) as exhibited in fig(6) the results of softening point are shown in fig (5). it can be seen that the highest softening point for the modified binder occurred at sbr content of (7%) which was (57.3 ºc) compared to the conventional asphalt cement (0%) sbr which was (48 ºc). the improvements of the above examined properties of the modified binder can be attributed to the distribution of fine sbr in the base asphalt which led to stiffening of the blend. this reflects the decrease in the penetration value and increase in softening point. the best improvements were obtained at (7%) sbr content. 5-2 effect of sbr on asphalt concrete mixture properties results were listed in table (6) and presented in fig.(7) , from this table the following points can be concluded: marshall stability value of the modified asphalt mixes is higher than that of the conventional asphalt mix. asphalt mix modified with (7%) sbr has higher stability value by (18%) than the conventional mix (0%) sbr. the modified asphalt binders produced mixes with higher flow values by (36%) at (7%) sbr in comparison with that of the conventional mix. also the mix density increased slightly with increasing the sbr content. as demonstrated in plot "d", the trend observed for the effect of sbr content on air voids values is exactly opposite to that observed between sbr content and density , for sbr content ranged from 0 to 7 percent, the air voids decreases with a rate of -0.092 percent for each 1 percent change in sbr content. the effect of sbr content on voids in mineral aggregate (vma) is exhibited in plot "e" , as its clear from the plot the vma decreases as the sbr content increases which means the increment in sbr content resulted in less spaces to be accommodated by asphalt binder. fn t t al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 5-3 effect of sbr on resilient modulus mr table (7) and fig (8) show the values of mr for the mixtures with different sbr contents. the results indicate that the polymer modifier has a remarkable effect on the mr values since the mr increased by 19 percent with increasing sbr content from 0 percent to 7 percent. after careful consideration, it was realized that the above findings are in agreement with the basic of strength of materials and asphalt theology phenomena, when axial pulsating load is applied on the specimen, tensile stresses are developed in the horizontal direction at the mid depth plane of the specimen, since the sbr has an improved elastic recovery therefore the modified asphalt concrete mixtures show higher resilient modulus value as the sbr content become higher. 5-4 effect of sbr on permanent deformation based on the data shown in table (8) and figure (9), it appears that the examined sbr contents have influence on the plastic response of the material as characterized by the intercept and slope values. the lowest value for the plastic strain accumulation with load repetitions (slope) is associated with the sbr content of 3 percent (0.305). also the sbr content of 3 percent showed the lowest intercept value of 90 microstrains. further increases in sbr content beyond 3 percent will lead to increases in slope as well as intercept values since the mixes offer more flexibility. 5-5 effect of sbr on flexural fatigue for the 40-50 penetration grade asphalt cement used in this study, sbr significantly affect the number of cycles to failure nf and provide an increased level of protection against cracking due to repetitive loading. this is due to the elastic effect of sbr on the asphalt binder as mentioned above. fatigue cracking coefficient (k1) and exponent (k2) are presented in table (9) for the conventional mix and mixes with 1, 3, 5 and 7 percent sbr content. values of 1k and 2k can be used as indicators of the effects of sbr on the fatigue characteristics of a paving mixture. the flatter the slope of the fatigue curve, the larger the value of 2k which indicates a potential for longer fatigue life. on the other hand, a lower 1k value represents a shorter fatigue life. as can be seen from fig (10) as the sbr content increase the 2k value increases and the 1k value decreases. these results highlight the improvement in fatigue resistance for mixes with high content of sbr. the fatigue life could reach the level of more than 83000 cycles for asphalt mix modified with 7% sbr and 40000 cycles for conventional asphalt mix, with an increase of 78% in nf. 6conclusions and recommendations within the limitations of materials and testing program used in this work, the following principal conclusions are made based on the findings of the investigations: 1sbr modification causes an increase in binder consistency (decrease in penetration and increase in softening point). the modification also reduces temperature susceptibility of the bitumen's, as indicated by increased penetration index. 2in comparison to conventional mixes with 0 percent sbr content, asphalt concrete mixes modified with 7 percent sbr has shown an increased marshall stability and flow at a rate of 18 and 36 percent, respectively. 3both air voids and voids in mineral aggregate are decreased slightly with an addition of sbr. the air voids and the voids in mineral aggregate decreases with a rate of -0.092 and -0.084 percent for each 1 percent change in sbr content, respectively. 4the addition of sbr with a rate ranged from 1 to 7 percent has shown an improved elastic property characterized with resilient modulus, the resilient modulus for mixes contain 7 percent sbr was 1.19 times that for mixes with 0 percent sbr. 5when 3% sbr is added as a polymer modifier, the asphalt concrete mixture displayed lower potential for permanent deformation compared to conventional mixes with 0 percent sbr. both the al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 slope and intercept values decrease 18 percent. an extra addition of sbr weakening the resistance for this type of distress. 6fatigue behavior of sbr modified mixes was found to be significantly improved compared to conventional mixes as determined by flexural test, the 2k value (inverse slope of fatigue line) and nf (fatigue life) for mixes with 7 percent sbr was more than that of 0 percent sbr by 60 and 78 percent, respectively. 7the use of 3 percent sbr has added to local knowledge the ability to produce more durable asphalt concrete mixtures with better serviceability. 7-references 1albayati, a. h, (2006),"permanent deformation prediction of asphalt concrete under repeated loading" ph.d. thesis, baghdad university. 23ai (1981), institute, manual series no.1, college park, maryland, usa 4a.i. al-hadidy, tan yi-qui (june/2010) "comparative performance of the smac made with the sbs and st-modified binders" journal of materials in civil engineering, pp 580-587. 5alkhashab. y.y.,(2009), "development of fatigue prediction model for local asphalt paving materials" ph.d. thesis, baghdad university. 6awanti,s.s. (april/2008) "laboratory evaluation of sbs modified bituminous paving mix" journal of materials in civil engineering, pp 327-330. 7bates r., worch r. federal aviation administration, faa (1987), " engineering brief no. 39, styrene-butadiene rubber latex modified asphalt", washington, dc, usa 8barksdale, r. (1972). , proceedings, third international conference on the structural design of asphalt pavements, london 9monismith, c., ogawa, n. and freeme, c. (1975). , trr 537. 10reynaldo roque, bjorn b., christos d.,greg sh. (september/2005) "guidelines for use of modified binders" uf project submitted to florida department of transportation, pp 1-102. 11scrb/9 (2003). general specification for roads and bridges, section r/9, hot-mix asphalt concrete pavement, revised edition. state corporation of roads and bridges, ministry of housing and construction, republic of iraq 12whiteoak, d (1990) "the shell bitumen handbook", shell bitumen. surrey, uk. 13xicheng qi, peter e. sebaaly, member, asce,and jon a. epps, member, asce (may/1995) "evaluation of polymer-modified asphalt concrete mixtures" journal of materials in civil engineering, pp 117-124. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 penetration grade 40-50 property astm designation test results scrb specifica tion 1-penetration at 25c,100 gm,5 sec. (0.1mm) d-5 48 40-50 2rotational viscosity at 135 c (cp.s) d4402 523 2softening point. ( c) d-36 48 3-ductility at 25 c, 5cm/min,( cm) d-113 >100 >100 4-flash point, ( c) d-92 291 min.232 5-specific gravity d-70 1.041 6residue from thin film oven test retained penetration,% of original ductility at 25 c, 5cm/min,( cm) d-1754 d-5 d-113 59.0 80 >55 >25 table(2) : asphalt concrete gradation sieve % passing weight 19 0.75 100 57.5 12.5 0.5 95 138 9.5 9.5 83 333.5 4.75 no.4 54 207 2.36 no.8 36 264.5 0.3 no.50 13 69 0.075 no.200 7 80.5 table (1) properties of asphalt cement al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 property astmdesignation test results scrb specification coarse aggregate 1. bulk specific gravity 2. apparent specific gravity 3. water absorption,% 4. percent wear by los angeles abrasion ,% 5. soundness loss by sodium sulfate solution,% 6. fractured pieces, % c-127 c-131 c-88 2.614 2.686 0.440 18 3.3 97 30 max 10 max 9 min fine aggregate 1. bulk specific gravity 2. apparent specific gravity 3. water absorption,% 4. sand equivalent,% c-127 d-2419 2.664 2.696 0.724 57 45 min. table (3): physical properties of aggregates al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 physical propertieschemical composition ,% % passing sieve no. 200 ( 0.075) surfac e area* (m2/kg ) specifi c gravity l.o.iso 3 fe2o 3 mgoal203 sio2cao filler type 2.412.2 3 limestone dust * blain air permeability method (astm c204) sbr content (%), by weight of asphalt cement) penetration softening point , ºc penetration index(pi) 0 48 48 -1.8035 1 46 49.6 -1.4876 3 43 51.5 -1.1719 5 38 55 -0.6469 7 35 57.3 -0.3393 table(6): marshall test results sbr % stability flow density gm max av vma 0 8.58 3.12 2.329 2.435 4.35 15.03 1 8.79 3.25 2.331 2.435 4.27 14.95 3 9.47 3.45 2.337 2.435 4.02 14.73 5 9.66 3.76 2.342 2.435 3.82 14.55 7 10.09 4.23 2.345 2.435 3.7 14.44 sbr % mr (psi) 0 122300 1 125400 3 132100 5 140300 7 145400 table (5) asphalt binder tests result table (7) resilient modulus test results table (4): properties of fillers al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 sbr % intercept slope 0 110 0.372 1 115 0.345 3 90 0.305 5 135 0.31 7 145 0.36 sbr % 0 1 3 5 7 i 3200 2800 2150 2300 1650 s 0.372 0.344 0.302 0.281 0.234 k1 1.965e-07 5.592e-08 5.482e-09 1.323e-09 2.179e-11 k2 2.688 2.907 3.311 3.559 4.274 figure (1) photograph of sbr polymer 3/ 4 1/ 2 3/ 8 n o. 8 n o. 50 n o. 20 0 n o. 4 0 20 40 60 80 100 1 10 100 1000 10000 sie ve size % p as si n g slected gradation specification limits table (8) permanent deformation parameters table (9) fatigue test results figure(2): aggregate gradation al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. (3) photograph for the prls 20 30 40 50 60 0 1 2 3 4 5 6 7 sbr content,% p en et ra tio n figure (4) effect of sbr content on penetration of asphalt binder al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (6) effect of sbr content on penetration index of asphalt binder 30 40 50 60 70 80 0 1 2 3 4 5 6 7 sbr content,% s of te ni ng p oi nt , c -3 -2 -1 0 1 0 1 2 3 4 5 6 7 sbr content,% p en et ra ti o n in d ex figure (5) effect of sbr content on softening point of asphalt binder al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (7) effect of sbr content on marshall properties astability bflow cdensity dair void 7 8 9 10 11 0 1 2 3 4 5 6 7 8 sbr content, % s ta b ili ty , k n 3 3.5 4 4.5 5 0 1 2 3 4 5 6 7 8 sbr content, % f lo w ,m m 2.3 2.325 2.35 2.375 0 1 2 3 4 5 6 7 8 sbr content, % d en si ty ,g m /c u .c m 3 3.5 4 4.5 5 0 1 2 3 4 5 6 7 8 sbr content, % a ir v o id s, % 14 14.5 15 15.5 16 0 1 2 3 4 5 6 7 8 sbr content, % v o id s in m in er al a g g .,% evoids in mineral agg. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 100 1000 10000 1 10 100 1000 10000 repetation p er m an en t m ic ro st ai n sbr = 0% sbr= 1% sbr= 3% sbr= 5% sbr= 7% 100000 110000 120000 130000 140000 150000 160000 0 1 3 5 7 sbr content, % r es ili en t m o d u lu s, p si figure (8) effect of sbr content on resilient modulus figure (9) effect of sbr content on permanent deformation al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 100 1000 100 1000 10000 100000 number of cycles in iti a te ns ile s tr ai n ( m ic ro st ar in ) sbr =0% sbr =1% sbr =3% sbr =5% sbr =7% figure (10) effect of sbr content on fatigue performance ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٦ فينول اللمادة مركبة مكونة من راتنج دراسة بعض الخواص الميكانيكية فورمالدهيد المقوى بألياف كيفالر الخالصة الخـواص الميكانيكيـة للمـادة على تغيير نسبة التقوية باأللياف تأثير دراسةهو هذا البحث إن الهدف من ذات كثافـة ) 0o-90o(وى بألياف كيفالر ثنائيـة اإلتجـاه الفينول فورمالدهيد المق ركبة المكونة من راتنج مال حيث تـم من مقاومة الصدمة ومقاومة الشد والصالدة وقد شملت هذه الخواص كل ، (485g/cm3)سطحية الفينول فورمالدهيد قبل التقوية باأللياف بعـدها تـم تـدعيم لراتنج الميكانيكية الخواص إستخراج في البداية ذلـك علـى الخـواص تأثير دراسة و (20%,40%,60%) من ألياف كيفالر ة مختلف ة وزني الراتنج بنسب .وكما موضح في المخططات البيانية ذكورةمال المادة المركبة ، الخواص الميكانيكية ، راتنج الفينول فورمالدهيد ، ألياف كيفالر: الكلمات الدالة study of some mechanical properties for composite material consist of phenol formaldehyde resin reinforced by kevlar fibers abstract the objective of this research is to study the effect of changed the reinforcement percentage by fibers on mechanical properties for composite material consist of phenol formaldehyde resin reinforced by biaxial kevlar fibers (0o-90o)(with (485g/cm3) density which included impact strength , tensile strength , and hardness where we extracted the mechanical properties for phenol formaldehyde resin before reinforced by fibers, then we reinforced the resin by different weight percentage from kevlar fibers(20%,40%,60%) and studied its effect on the above mechanical properties as illustrated in the diagrams . keywords:-composite material , mechanical properties, phenol formaldehyde resin , kevlar fibers . علي إبراهيم الموسوي بابل-المعهد التقني مشتاق طالب البديري جامعة القادسية ali i.al-mosawi technical institute babylon mushtaq t. al-bdiry qadissiya university ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٧ )introduction( المقدمة ستخدمها البابليون في إ عدة حيث قرونبسط صورها منذأ تقنية تصنيع المواد المركبة برفتُْع تتكون المادة المركبة من دمج . بناء بيوتهم عن طريق خلط نشارة الخشب بمادة الطين لتقويته مختلفتي )reinforced plastic( والبالستك (blends)مادتين أو أكثر وتشمل الخالئط إن عملية الدمج هذه تؤدي إلى الحصول على مادة جديدة . الخواص الميكانيكية والفيزياوية يوجد في . ذات خواص هندسية وفيزيائية تختلف عن خواص المواد الداخلة في تركيبها السليلوز مع مادة ألياف على المواد المركبة ومنها األمثلةالطبيعة الكثير من األكثر الصناعية هي باألليافن تقوية الراتنجات إ في الصناعة فأما .]١٩٩٩حليم[الخشب -: لتصنيع مادة مركبة يجب توفر مادتين هما و. نتشاراًإ (matrix material) المادة األساس -١ متكونة من المعادن وسبائكها ) metallic materials( تكون مواد األساس أما مواد معدنية ceramic materials)(ميز بثقل وزنها ومتانتها العالية ،أو قد تكون مواد سيراميكيةوتت والتي تمتاز بخفة وزنها ومقاومتها المرتفعة لدرجات الحرارة العالية ولكنها ضعيفة المقاومة وهي polymeric materials)(كذلك تكون المادة األساس مواد بوليميرية. لقوى الصدم وإنتشاراً ِلما تتميز به من خواص ميكانيكية وحرارية جيدة ، ومن األمثلة األكثر إستعماالً .]١٩٩٩حليم[راتنج الفينول واإليبوكسي والبولي أستر على المواد البوليمرية (reinforcing material)مادة التقوية -٢ ة حتى ض المنخفليةي في هكذا مواد وهي المقاومة العالية والمطأساسيتينن ييجب توفر ميزت reinforcing(هناك عدة طرق للتقوية منها التقوية بالدقائق . األساستستطيع تقوية المواد by (particulate كبر من أكون بقطر ت والتي( 1 µm ) برية إل مختلفة منها اوبأشكال ويكون reinforcing by dispersed)(شرية ، كذلك تتم التقوية بالتشتتوالكروية والِق التقوية التقوية شيوعاً فهيأساليبكثر أ أما. ( 0.1µm )قل من أطر الدقائق ق نظراً لما تتميز به من قوة كبيرة مقارنة بالمواد reinforcing by fibers)(باأللياف أو طع مقَأو بأنواع وأشكال مختلفة فمنها ما يكون بشكل مستمر األليافالراتنجية ، وتكون . ]١٩٩٩محلي[بشكل ظفائر محاكة ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٨ إن اإلستخدام العام للمادة المركبة يعتمد بشكل كبير على الخواص الميكانيكية والفيزيائية لهذه لذلك فإن دراسة هذه الخواص تحت تأثير القوى واألحمال في ظروف مختلفة يكتـسب المواد .كبيرة لمعرفة مدى مالئمة هذه الخواص لمكان عمل هذه المواد أهمية )fibers reinforcing(األلياف التقوية ب هو لتحسين الخواص الميكانيكية والفيزيائية للراتنجات إن الهدف الرئيسي من التقوية باأللياف هذه المواد المقواة يسمح بإستخدام حيث تزداد مقاومة الشد والصدمة والصالدة بشكل كبير مما لمـواد المركبـة بالمتقدمـة يطلق على هـذا النـوع مـن ا . عنيفة في مجاالت صناعية (advanced composites) وذلك لتفريقها عن المواد المحشوة)filled polymers. ( إن في هذا النوع من المواد المركبة هي المسؤول الرئيسي عن تحمل األحمال الخارجيـة األلياف الزجـاج أنواع األلياف شيوعاً في مجال المواد المركبة المتقدمـة هـي أليـاف ، ومن أكثر .]٢٠٠٠ طاهر[والكاربون وألياف كيفالر . ) phenol formaldehyde resin(راتنج الفينول فورمالدهيد يعتبر راتنج الفينول فورمالدهيد من أقدم الراتنجات المستخدمة تاريخياً ، حيث يتم تحضير هذا والعامل المحفز المـستخدم الراتنج من تفاعل الفينول مع الفورمالدهيد ليعطي مركبات تكثيفية المستخدم وعلـى النـسب أو قاعدة وطبيعة الراتنج الناتج تعتمد على نوع المحفز أما حامض يستخدم راتنج الفينول فورمالدهيد في . ) الفينول والفورمالدهيد (الجزيئية بين المواد المتفاعلة بمقاومة حرارية وعزل كهربائي الكثير من العمليات الصناعية ومنها إنتاج األوعية التي تمتاز وكذلك يستخدم في تطبيقات الفضاء كونه يتحول في درجات الحرارة العالية إلـى الكـاربون المكـوك الفـضائي وغيرهـا مـن التطبيقـات ليكون طبقة متفحمة عازلة وحامية لمقدمـة . رمالدهيد يوضح التركيب الكيميائي لراتنج الفينول فو)١(الشكل رقم .]efunda2001[اُألخرى .)composite materials properties (خواص المواد المركبة تعتمد اإلستخدامات العامة والهندسية للمواد المركبة إلى حد بعيد على خواصـها الميكانيكيـة ومقاومتها للحرارة والظـروف والفيزيائية مثل مقاومة الشد والمرونة وقابلية المادة للإلستطالة إن جميـع هـذه . مثل الرطوبة وأشعة الشمس وغيرها من الخواص التطبيقية اُألخرى ة البيئي الخواص تعتمد كثيراً على التركيب الجزيئي للراتنج وعلى وزنـه الجزيئـي وعلـى القـوى إلى حد كبير على مواد التقوية وعلى المواد كما تعتمد هذه الخواص . ]١٩٩٤سويلم[الجزيئية :ومن الخواص المناقشة في هذا البحث ما يأتي . والملدنات المضافة مثل الحشوات ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٩ . (impact strength)مقاومة الصدمة -١ تحت تأثير حمل مفاجئ ، كمـا تعتبـر تُعبر مقاومة الصدمة عن قدرة المادة لمقاومة الكسر ويمكـن . للصدمة التي تبدي أعلى مقاومة مقياساً لمتانة المادة حيث المواد األكثر متانة هي بإضافة بعض المحسنات مثل مطاط بيوتـادين أو إضـافة تحسين مقاومة الصدمة للراتنجات الطرق فاعليـة فـي تحـسين الملدنات أو بترتيب وتراصف السالسل البوليمرية ولكن أكثر .مقاومة الصدمة هي التقوية باأللياف . ( tensile strength)مقاومة الشد -٢ المـادة د مقياساً لقابلية المادة على مقاومة القوى الساكنة التي تحاول سحب تعتبر مقاومة الش ساس التـي األمادة التتكون المواد المركبة الليفية من ألياف قوية هشة مغمورة في . وكسرها تبدأ المادة المركبة باإلستطالة بشكل خطي في البداية إسـتجابة . تتصف بكونها أكثر مطيلية مادة األساس إلى نقطـة المع إستمرار التحميل يحصل إنحراف نتيجة لوصول للجهد المسلط و ــاف ــستمر األلي ــين ت ــي ح ــضوع ف ــار الخ ــى تنه ــة حت ــتطالة و المقاوم باإلس . تفشل المادة المركبة كلياً تتهشم المادة األساسوعندما .]lubin1976[مقاومتها .(hardness) الصالدة -٣ عالميـة المادة للخدش أو اإلختراق ، وهنالك ِعدة مقـاييس على إنها مقاومة رف الصالدة عتُ وصـالدة وأكثرهـا شـيوعاً صـالدة برينـل مختلفة لتعيـين صـالدة المـواد اللدائنيـة في سطح النموذج أثناء تسليط القـوة يحدث اإلختراق بمعدل بطيء .]١٩٩٥أمل [روكويل القـوة المـؤثرة تحـصل ، وبعد زوال مما يؤدي إلى حدوث زحف موضعي ألجل اإلختبار في حساب صـالدة إستعادة بطيئة نسبياً في اإلختبار مما يؤدي إلى تغيير أبعاد األثر المعتمد ولمنع حدوث ذلك يتوجب اإللتزام بالفترة الزمنية المحددة لتسليط القـوة علـى سـطح المادة كشف سريع لما يطـرأ تبرز أهمية إختبارات الصالدة في إعطاء . ]crum1997[النموذج من تغيرات على الخواص الميكانيكية للمادة نتيجة لعمليات التـصنيع والتغيـرات الكيميائيـة .والمعامالت الحرارية والتعتيق والتغيرات المصاحبة لعمليات التشكيل ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٠ )experimental work(الجزء العملي فية تحـضيرها إضـافة إلـى اإلختبـارات يتضمن الجزء العملي تحضير المواد األولية وكي .الميكانيكية التي تم إجراءها على المادة المركبة .المواد المستخدمة في البحث -أوالً :تم في هذا البحث إستخدام المواد التالية والتي تم تصنيع النماذج منها وهي ( phenol formaldehyde resin) راتنج الفينول فورمالدهيد -1 .متلك راتنج الفينول فورمالدهيد مقاومة حرارية وكيميائية جيدة وذو قابلية إشتعال واطئة ي (kevlar fibers)ر ألياف كيفال-2 والذي يحضر بـالبلمرة poly(p-phenyleneterephthalamide)وهي عبارة عن بوليمر هــذه . (p-phenylenediamine) و(terephthaloyl chloride)التكثيفيــة لمركبــي األلياف تكون بهيئة سلسلة بوليمرية خطية غير متقطعة نتيجة الترابط الموجه لحلقات البنزين في هذا البحث تـم إسـتخدام . ر يوضح التركيب الكيميائي أللياف كيفال )٢(والشكل رقم ، .(485g/cm3)سطحية ذات كثافة ) 0o-90o(ألياف كيفلر بشكل ظفائر محاكة ثنائية اإلتجاه . (test specimens preparation) تحضير النماذج -ثانياُ :تم في هذا البحث تصنيع ثالثة أنواع من النماذج خاصة باإلختبارات التي تم إجراءها وهي .(impact specimens)نماذج إختبار الصدمة -١ ـ (astm-e23) إختبار الصدمة حسب المواصـفات القياسـية نماذج تم تصنيع ة والمالئم 0.5)عمق الحز في النمـاذج . (charpy impact)للفحص في جهاز الصدمة نوع شاربي mm) ونصف قطر قاعدة الحز (0.25 mm) وبزاوية حز مقدارها)º45 (. .(tensile specimens)نماذج إختبار مقاومة الشد -٢ ـ (iso – r – 527)تم إعتماد المواصفة القياسية ة الـشد في تصنيع نماذج إختبـار مقاوم .)٣(الشكل رقم والموضحة في . (hardness specimens) ة إختبار الصالدنماذج -٣ ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦١ a f =σ a e r = وسـمك (mm 25) أقـراص دائريـة بقطـر تم تصنيع نماذج إختبار الصالدة على شـكل (10 mm) تالئم إختبار الصالدة بطريقة برينل. لتـصنيع عينـات (20%,40%,60%)يـاف كـيفالر تم إضافة نسب وزنية مختلفة مـن أل اإلختبارات أعاله وبواقع ثالث عينات لكل نسبة وزنية وأخـذ معـدل القـراءات لتقلـيص .اإلنحراف الحاصل في النتائج إن وجد .(mechanical tests) اإلختبارات الميكانيكية –ثالثاً نيكية للتعُرف على خواص المادة المركبـة ، تم في هذا البحث إستخدام ثالثة إختبارات الميكا :وهذه اإلختبارات هي .(impact test) إختبار الصدمة -١ (charpy impact instrument)ُأستخدم جهاز فحص مقاومة الـصدمة نـوع شـاربي ويمكن حـساب مقاومـة .الكاربون .مل الصدم للتعُرف على مدى مقاومة المادة المركبة لحِ :من المعادلة التالية الصدمة :حيث r = مقاومة الصدمة(kj/m2). e = الشغل أو الطاقة. a = مساحة المقطع العرضي لنموذج اإلختبار(mm2). .( tensile test)إختبار مقاومة الشد -٢ خواص المادة المركبة تحت تأثير ِحمل شـد محـوري بإتجـاه لمعرفة رُأستخدم هذا اإلختبا في قياس هذه (universal instrument)م إستخدام جهاز اإلختبارات العام ، حيث تواحد :ويمكن حساب مقاومة الشد من القانون اآلتي . (kn 20)الخاصية وبمعدل ِحمل :حيث σ = مقاومة الشد (n/m2). f = الحِمل المسلط (n). a = العرضي للنموذج مساحة المقطع(m2). . ( hardness test) ةإختبار الصالد -٣ ، حيـث المـادة المركبـة ة صالد لحساب(brinell hardness) لتم إستخدام طريقة برين (sec 15)لمدة (kg 10) مع تسليط ِحمل مقداره (mm 5)ُأستخدمت كرة فوالذية بقطر ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٢ ( )22 2 ddd d p hb −−⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × = π ويمكـن إسـتخراج قـيم . األثر الناتج على السطح قياس قُطر يتموبعد زوال القوة المؤثرة :الصالدة من العالقة التالية :حيث hb = لصالدة برين (n/m2). p = الُمسلطة القوة (n). d= اإلختبار قُطر كرة (mm). d = قُطر األثر الناتج على السطح(mm). .) discussionresults and(النتائج والمناقشة في مجال إستخدام هكذا مواد ، حيـث ركبة أهمية كبيرة متمتلك الخواص الميكانيكية للمادة ال ومن خـالل هـذه . حتى تؤدي عملها بكفاءة يجب أن تكون قيم هذه الخواص عالية ومقبولة إلتجـاه اإلختبارات التي ُأجريت على راتنج الفينول فورمالدهيد المقوى بألياف كيفالر ثنائية ا والتي تُمثل قيم مقاومة الـشد ومقاومـة حصلنا على النتائج الموضحة في المخططات البيانية .الصدمة والصالدة نسبة إلى نسبة التقوية باأللياف يوضح قيم مقاومة الصدمة مع نسبة التقوية باأللياف ، )٤(الشكل رقم . ةمقاومة الصدم -١ ولكن بعد تقويتهـا منخفضة للراتنجات نظراً لهشاشتها حيث تعتبر مقاومة الصدمة بشكل عام باأللياف تزداد قيمة مقاومة الصدمة ويرجع السبب في ذلك إلى كون األلياف سـوف تتحمـل وهكـذا .المسلطة على المادة المركبة مما ُيحسن هذه المقاومة الجزء األكبر من طاقة الصدم %) .٦٠(و %) ٤٠(األلياف إلىتزداد مقاومة الصدمة مع زيادة نسبة التقوية ب تعتبر الراتنجات من المواد الهشة حيث مقاومتها للشد منخفضة جداً وهـذا . مقاومة الشد -٢ ، ولكن عند إضافة األلياف إلى هذه المواد تتحسن مقاومتها للـشد )٥(الشكل رقم ما نراه في لياف مما يرفع مقاومة الشد بصورة كبيرة حيث إن الجزء األعظم من الجهد المسلط تتحمله األ وتزداد مقاومة الشد بزيادة نسبة . للمادة المركبة وذلك ألن األلياف تتميز بمطيليتها المنخفضة األلياف المضافة حيث تشِغل األلياف حيز أكبر داخل الراتنج مما يسمح بتوزيع الِحمل المسلط .عليها بشكل أفضل ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٣ الشكل رقم بشكل عام بإنخفاض صالدتها حيث نالحظ من تتميز المواد اللدائنية . الصالدة -٣ تدني قيمة صالدة راتنج الفينول فورمالدهيد قبل التقوية باأللياف ، إال إن قيمة الـصالدة )٦( ترتفع بشكل حاد عند التسليح بألياف كيفالر نظراً لتوزيع الِحمل على األلياف مما يقلل معـدل وتزداد صالدة المادة المركبة مع زيـادة . فع قيم صالدتها اإلختراق لسطح المادة المركبة وير .نسبة األلياف المضافة لنفس السبب المذكور أعاله .)conclusions (اإلستنتاجات :من خالل النتائج التي تم الحصول عليها يمكن الخروج باإلستنتاجات التالية . كونه من المواد الهشة ورمالدهيد الفينول فإنخفاض قيم الخواص الميكانيكية لراتنج -١ لراتنج الفينول فورمالدهيد بعد تقويته بألياف كـيفالر تحُسن قيم هذه الخواص الميكانيكية -٢ . ثنائية اإلتجاه ألن الِحمل األكبر المسلط على المادة المركبة الناتجة سوف تتحملـه األليـاف .ياف المضافة وتزداد قيم الخواص الميكانيكية مع زيادة نسبة األل .)references(المصادر ، رسالة ماجـستير، جامعـة “المقساةتحسين خواص المواد اللدائنية ” علي هوبي حليم -١ .١٩٩٩ ، بابل دار المريخ للنشر ، الرياض “ أساسيات علم وتقنية البلمرات” عبد الفتاح محمود طاهر . د -٢ . ٢٠٠٠ المملكة العربية السعودية ، 3-efunda engineering fundamentals “polymer material properties” ,2001. (www.efunda.com). ، الطبعة األولى “ تشغيلهاطرق تصنيعها أنواعها -اللدائن ماهيتها ” عادل محمد سويلم -٤ .١٩٩٤زيع ، ، دار الكتب العلمية للنشر والتو 5george lubin “ handbook of fiberglass and advanced plastics composite ”, first edition , 1975. ، “ هجينـة مواد مركبـة و لمواد مركبة الخواص الميكانيكية دراسة ” أمل علي رجب -6 . ١٩٩٥رسالة ماجستير، هندسة المكائن والمعدات ، الجامعة التكنلوجية ، 7n.g.mccrum, c.p.buckley and c.b.bucknal “principal of polymer engineering” , second edition , oxford university press , 1997 . ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٤ ]٢٠٠٠ طاهر[يائي لراتنج الفينول فورمالدهيد التركيب الكيم :)١(والشكل رقم co co – nh nh ]crum1997[التركيب الكيميائي أللياف كيفالر : )٢(الشكل رقم 24 mm 155.5 mm 8mm 24.5 mm 24.5 mm 24 mm 18 m m نموذج إختبار مقاومة الشد) : ٣(الشكل رقم ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٥ 0 20 40 60 80 0 100 200 300 400 500 لراتنج الفينول فورمالدهيد المقوى بألياف كيفالر إختبار مقاومة الشد :) ٥(الشكل رقم reinforcing percentage (%) t en si le s tr en gt h ( n /m 2 ) لراتنج الفينول فورمالدهيد المقوى بألياف كيفالر اومة الصدمة إختبار مق:) ٤(الشكل رقم reinforcing percentage (%) im pa ct s tr en gt h (k j/m 2 ) 0 20 40 60 80 0 50 100 150 200 250 ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٦ 0 20 40 60 80 0 20 40 60 80 100 reinforcing percentage (%) h ar dn es s ( n /m 2 ) هيد المقوى بألياف كيفالرإختبار الصالدة لراتنج الفينول فورمالد) : ٦(الشكل رقم study of traffic safety evaluation and improvements at unsignalized intersection al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 study of traffic safety evaluation and improvements at unsignalized intersections hameed aswad mohammed assistant lecture engineering college / al-anbar university abstract highway traffic safety is an important area in transportation engineering. highway intersections are nodes of road networks and accident-prone locations. they are the places where vehicles coming from different approaches and moving towards different directions interact and conflict with each other. due to the conflicts from all users, more traffic crashes could happen at unsignalized intersection as compared with roadway segments. popular methods which are based upon traffic accidents and traffic conflicts are proved to be effective in certain circumstances, but difficulty in data collection of traffic crashes and subjective judgment and determination of traffic conflict constrain their applications. this paper introduces an approach to evaluate and improve unsignalized intersection safety performance. this method is fully based on the existing conditions of unsignalized intersection, including geometric design, sight distance, pavement surface conditions, traffic control devices, and lighting, etc. different from the crash-based and conflictbased methods, this approach is a non-crash and non-conflict based analysis method. this approach needs to go through a field survey to unsignalized intersection to be evaluated. in this approach, a safety index is introduced to give a diagnostic summary of the safety performance degree of unsignalized intersections. corresponding countermeasures are ranked and recommended based on the cost benefit analysis. in this paper, the approach (called diagnostic approach) is practically applied to evaluate and improve the safety performance of some unsignalized intersections in fallujah city of iraq. keywords: highway safety, unsignalized intersection, safety evaluation, safety improvements دراسة لتقییم وتحسین السالمة المروریة على التقاطعات بدون اإلشارة الضوئیة حمید أسود محمد كلیة الهندسة/ مدرس مساعد جامعة األنبار موجـــــــزال هيتقاطعات الطریق تكون بمثابة العقد في شبكة الطریق وتكون.السالمة المروریة للطریق تكون المجال المهم في هندسة النقل التقاطعات تكون هي المواقع حیث المركبات القادمة من مختلف المداخل والمتحركة نحو مختلف .األماكن المعرضة للحوادث بسبب الحركات المروریة المتعارضة من قبل كل المستخدمین فأن كثیر من .االتجاهات المتداخلة والمتعارضة مع بعضها البعض الطرق العامة التي تعتمد .األخرىبدون اإلشارة الضوئیة بالمقارنة مع مقاطع الطریق حوادث االصطدام سوف تحدث في التقاطعات على بیانات الحوادث المروریة والحركات المروریة المتعارضة قد أثبتت بأنها تكون فعالة في ظروف معینة لكن الصعوبة تكون في تحدید الحركات المروریة المتعارضة كل هذا یقید تطبیق جمع البیانات لحوادث االصطدام المروریة والقرار الشخصي وأیضا في study of traffic safety evaluation and improvements at unsignalized intersections al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 151 هذه الطریقة تكون . هذا البحث یقدم طریقة لتقییم وتحسین أداء السالمة المروریة في التقاطعات بدون اإلشارة الضوئیة.هذه الطرق طبیعة سطح ،یم الهندسيبالكامل معتمدة على الظروف الموجودة في التقاطعات بدون اإلشارة الضوئیة والتي تتضمن التصم االختالف عن الطرق التي تعتمد على بیانات حوادث االصطدام والحركات .الخ... ،واإلنارة،وسائل السیطرة المروریة،التبلیط في هذه الطریقة یكون دلیل .المتعارضة فان هذه الطریقة التعتمد على تحلیل بیانات الحوادث المروریة والحركات المتعارضة التحسینات .ادخل لكي یعطي ملخص تشخیصي لدرجة أداء السالمة المروریة في التقاطعات بدون اإلشارة الضوئیةالسالمة قد ( في هذا البحث تكون الطریقة . المطبقة على التقاطعات تكون مصنفة وكذلك التوصیة تكون معتمدة على تحلیل منفعة الكلفة حسین أداء السالمة المروریة لبعض التقاطعات بدون اإلشارة الضوئیة في مدینة مطبقة عملیا لتقییم وت) تدعى الطریقة التشخیصیة . الفلوجة في العراق introduction with the rapid growth of the number of various vehicles, the ratio of the traffic accidents to vehicle number is increasing greatly. the road accident results in serious social problem and economic problem. traffic safety is becoming more and more important for both drivers and the whole society [22]. intersections are critical components of highway network and are used by all road users-passenger cars, heavy trucks, motorcycles, bicycles, and pedestrians. they are among the greatest safety challenges because they are some of the most common highway features, each having numerous conflict opportunities [6]. unsignalized intersections with yield control or stop signs on the minor roads are one of the most common intersection types in the street system in iraq [12]. unsignalized intersections are of particular concern because there are so many of them on the highway system and because some experience sufficient number of particular crash types to indicate a need to improve safety. good geometric design combined with good traffic control can result in an intersection that operates efficiently and safety [3]. unsignalized intersections represent potential hazards not present signalized intersections because of the priority of movement on the main road [2]. the safety condition of intersection has a great influence on the traffic safety of the road network in the region. in order to improve the traffic safety of road net, and decrease the number of traffic accidents, it is necessary to reasonably evaluation the intersection safety conditions. there are mainly two types of intersection safety evaluation methods: one is direct evaluation which is based on the statistics of traffic accidents, the other is indirect evaluation which is based on traffic conflict technique [5]. direct evaluation method mainly includes crash frequency, crash rate, crash severity, and crash statistic models. however, when these methods applied, the evaluation result's accuracy is affected because of long period and inaccuracy of statistical data. to accumulate intersection crash data could be a problem to many researchers, mainly due to the difficulty to obtain these data and the reliability of past crash data. the indirect evaluation method based on traffic conflict technique is a relatively new traffic safety evaluation method, which is mostly applied to evaluate intersection traffic safety by the ratio of conflict number and traffic flow [20]. traffic conflict technique methods generally cover conflicting points, number of conflicts, conflict rate, conflict distribution, and conflict forecasting models [16]. however, this method also has shortcomings, such as the inaccuracy of the observed traffic conflicts numbers, and the lack of proper division of traffic conflicts according to different traffic conflicts various effects on traffic safety. the judgment and determination of traffic conflicts are more subjective nature. different observers may give different traffic conflict judgments. in addition, traffic conflict technique is a time consuming task. although traffic conflict technique has such problems, this technique method has been used by many researchers to analyze intersection traffic safety performance [17]. as discussed above, both crash-based and conflict-based safety analysis methods have some limitations in real applications. in the research presented in this paper, another approach called diagnostic approach was attempted. this approach is purely based on the existing intersection conditions, such as geometric, channelization, sight distance, pavement surface conditions, lighting, approaching traffic speed, etc. different from the crash-based and conflict-based methods, this approach is a non-crash and non-conflict based analysis method. with such characteristics, this approach could give a relatively fast evaluation to intersection safety performance. in this approach, a safety index hameed aswad mohammed al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012152 is introduced to give a diagnostic summary of the safety performance of an intersection [4]. usually, non-crash and non-conflict based evaluation methods can give a safety evaluation to road facility with a relatively short time period and are relatively easy to be implemented in real applications. particularly, this type of approach has advantages, such as low cost, high efficiency, and less time-consuming. furthermore, this type of approach can be better used by field safety engineers to find potential safety problems and corresponding countermeasures can be implemented with short time period so that possible traffic safety problems can be prevented [4]. collision at unsignalized intersection accidents caused by drivers who fail to stop are becoming increasingly frequent at unsignalized intersections on the state highway system. the major crash type unsignalized intersections is a right angle crash involving a vehicle entering the intersection from the stop approach and a vehicle on the through approach. a traffic crash occurring as a result of a driver disregarding a stop sign has the potential to be a severe collision since it typically involves a right angle type of impact “disregarding a stop sign “was listed as a contributing [3]. causes of traffic accidents at unsignalized intersections causes of traffic accidents are rather complex, usually concerning several factors including human, vehicle, geometric design, and the environment. and the causes usually vary with the different characteristics of the different parts of highway system. compared with roadway segments, intersections are characterized by the intensely concentrated intersections and conflicts of highway users from different approaches and towards different exists. it is almost always unavoidable that someone gets in the way of another one from time to time and the complicated maneuvers of turning left or right make such conflicts even more serious. unfavorable human factors such as fatigue, inexperience, drunk driving and bad emotions, unfavorable environmental factors such as insufficient sight distance, slippery pavement and cloudy weather and unfavorable vehicle conditions might be combined to make such conflicts become traffic crashes. from the above discussion, it is easy to see that the essential causes of traffic accidents at highway intersection are the frequent interactions and conflicts among different highway users. many other factors help to make some of the conflicts into traffic accidents. in fact, major safety improvement measures such as stop or yield, speed control, channelization, and lighting are mainly designed to mitigate or eradicate the interactions, conflicts, and accidents [15]. selection of evalution method traffic safety is influenced by lots of factors such as roadway geometric, road surface condition, traffic management and control, weather condition, driver behavior and so on. considering data collection and processing, it is not feasible to identify all the factors, where only a few can be easily obtained and analyzed to estimate unsignalized intersection safety [1]. diagnostic approach is used to evaluation unsignalized intersections safety performance which is based on the existing conditions that have direct relationships or impacts to traffic safety at unsignalized intersections [1]. methodology the evaluation method can be described by a flow process as shown in figure 1. the following subsections give a brief description to each step shown in figure 1. potential safety problems are ranked according to the criteria such as the significance and severity. after safety problems with the highest ranks are identified, possible countermeasures are proposed and the cost-benefit analysis is performed to estimate the benefit-cost ratio for each countermeasures. finally, corresponding countermeasures with the highest benefit-cost ratios are recommended to improve unsignalized intersection safety [4,9,10,13,18]. study of traffic safety evaluation and improvements at unsignalized intersections al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 153 field survey form for intersection safety diagnostic process, field surveys are necessary. field engineers use the survey forms in the fields to perform diagnostic process by filling the survey forms (also called safety diagnostic forms) with information collected from each intersection. the basic information (elements) in the form covers intersection existing conditions that have direct relationships to traffic safety at intersections. typical elements for unsignalized intersection include, but not limited to, geometric, channelization, sight distance, and pavement surface conditions, lighting, and approaching speed. field engineers with check these elements at each intersection and they will give two scores to each element based on their personal judgments. one score is under the category of "significance" and the other one is under the category of "severity". the category of "significance" indicates whether the particular condition (such as lighting) at the intersection has significant safety problem with a score of "0" indicating not significant and "5" very significant, and the category of "severity" indicates whether the particular safety problem associated with the particular condition (such as lighting) would result in a severe traffic crash with a score of "0" indicating not severe and "5" very severe. table 1 presents the field survey form (safety diagnostic forms) with most existing conditions (elements) included. field engineers need to fill scores for each element under the categories of “significance" and "severity". this form is relatively easy to be used in fields by an "average" field engineer [4, 10, and 13]. selection of intersection for safety evaluation the process to determine the sites (intersections) in an area or roadway can be based on the past traffic crash history or a preliminary field safety survey. the number of sites for detailed field survey is really based on the budget limitations [4]. identification of safety problems field surveyors need to use the survey form to survey each intersection. the survey items cover all related conditions. the surveyors need to use their field experience to judge the potential safety problems associated with the existing conditions at each intersection; filling in the diagnostic table mainly depend on the researcher's own practical experience, significance and severity evaluation criterions, which are established according on present criterions, guides practical experience and the expert's suggestion, the purpose is to provide a uniform reference of the safety problems to the researchers [9,10]. ranking of safety problems after completion of field survey and identification of intersection potential safety problems, the potential safety problems should be ranked. some safety problems may be significant, but would not result in severe traffic crashes, and some safety problems may not be significant, but could result in severe traffic crashes. thus, the indices "significance" and "severity" are used in ranking the potential safety problems. with the consideration of significance and severity, a safety index is introduced to rank a particular safety problem, such as non-sufficient sight distance for a given intersection. the safety index can be calculated by the following equation [4, 10, 13, and 18]: ri= w1ci + w2si (1) (i= 1, 2, 3…., n) where: ri= safety index for the ith safety problem, w1= weight for significance index, ci= significance index for the ith safety problem, w2= weight for severity index, si= severity index for the ith safety problem, and n= number of the safety problems. hameed aswad mohammed al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012154 the safety index ( ri ) represents the ranking of each particular safety problem, and if the ( ith ) particular safety problem has a large ( ri ) value, this problem should have a higher rank for safety improvements. to use equation (1), the weights (parameters w1 and w2) should be estimated. in this research, the interview with experts was used to estimate the two parameters. with the data collected from the interviews, the final parameters are: w1=0.37 and w2=0.63, or equation (1) has the following form: ri= 0.37ci + 0.63si (2) (i=1, 2, 3,…, n ) in order to rank intersections for safety improvements, the overall safety index ( y ) for a particular intersection is used and described by equation (3): y=∑ ri (3) the overall safety index is the summary of the safety index for each particular potential safety problem. a larger (y) value means the corresponding intersection has more significant and/or severe safety problems. list possible safety countermeasures the selection of possible safety countermeasures should follow several principles such as (1) reduction of crash rate and crash severity, (2) reduction of the conflicts between non-motorized users and motorized vehicles, and (3) reduction of conflicts between vehicles. the selection of possible roadway safety countermeasures is relatively simple. generally, one safety problem could have several countermeasures. on the other hand, one safety countermeasures could solve several safety problems. many documents present potential roadway safety problems and corresponding possible safety countermeasures [10, 21]. ranking of possible safety countermeasures aiming at unsignalized intersection safety problems got from the field diagnosis, possible improving countermeasures are put forward from geometric design, management facilities, maintenance and other aspects. many countermeasures to improve unsignalized intersection safety are difficult to be fulfilled because of shortage of fund, which leads to more traffic safety problems. under this situation, it is necessary to offer some low cost, easy to operate countermeasures to solve the traffic safety problems. comparing the countermeasures to improve the traffic safety, it can be found that they are different in cost and efficiency. therefore it is necessary to make sort analysis among the improving countermeasures. it applies benefit cost ratio to rank and optimize the possible improving countermeasures: bcr=b/c (4) where: b= total benefit of the improving countermeasures, c= total cost of the improving countermeasures. with the equation (2), the engineers can get the order of all the possible improving countermeasures and choose the economical and feasible countermeasures. (bcr) values can be used to rank possible safety countermeasures. the countermeasures with a larger (bcr) value should have higher priority ( high rank ) for implementation. in real application, due to the budget limitations, not all safety countermeasures will be implemented. only the countermeasures with higher priority will be implemented [4, 10, 13, and 23]. study of traffic safety evaluation and improvements at unsignalized intersections al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 155 determination of safety countermeasures technically, the ranking of possible countermeasures can be used to determine safety countermeasure that will be implemented. in other words, equation (4) or (5) is used to calculate the benefit-cost ratio for each possible safety countermeasure. if the implementation budget allows to the installation of countermeasures, the top countermeasures with the highest benefit-cost ratios will be selected for real implementation [4, 10, and 18]. application of case study there are many numbers of unsignalized intersections in fallujah city. all the unsignalized intersections are in flat area and many of these intersections are controlled by police men or by signs and some of intersections are uncontrolled. several of intersections are located in major arterials or in local roads and their main function is mobility. according to past crash data, the some of unsignalized intersections have a high annual crash rate. site visits was conducted at most intersections to determine the intersection characteristics. these characteristics reviewed included traffic control, sight distances, pedestrian facilities, road surface condition, crosswalk facilities, geometric design, lighting, vehicle speeds, and on-street parking. this research has planned to evaluate and improve the safety performance of unsignalized intersections in fallujah city. therefore, there is a need to rank the safety problems at these intersections caused by existing conditions and rank the possible safety countermeasures. based on field observations, there are some notices at unsignalized intersections in fallujah city: • with on-street parking close to the intersection approach, turning vehicles might have to stop if parallel parking maneuvers occur in the exit lanes, possible resulting in rear-end and side-swipe collisions. vehicle entering and exiting the back lanes close to intersection also increase the collision risks. • lighting is not provided along the intersection approaches and at the most intersections may increase the frequency of collisions as night. • lack of visibility of traffic signs may contribute to crash experience at intersections. visibility of traffic signs at intersections may be obstructed by physical objects (such as signs or other vehicles) or may be obstructed by weather conditions, such as fog or bright sunlight. • marked crosswalks are not provided across the legs of the intersections lead the pedestrians to use the roadway and increase the collision risks between pedestrian and vehicles. • there is a lack of geometric design of some intersections. • it was noted that the pavement surface of some intersections has distresses at different levels. • traffic conflict at the intersection is high, meaning traffic safety is not good. • several of intersections have limits the sight distances for some approaches. field survey was performed by several field engineers (surveyors) have sufficient safety and operational experience and were well trained in using the diagnostic survey forms. in the research, the diagnostic approach was applied to evaluate the safety performance of the intersections f1, f2, and f3 which are showed in figure 2. tables 2 and 3 summarized the survey results ( scores under the categories of " significance " and " severity " ).according to the traffic safety problems ranking model ( equation 2 ), the total score and the order of traffic safety affecting degree can be gained. table 4 listed the safety problems and corresponding safety scores (which are the average scores from all surveyors) under the categories of “significance” and “severity ". in the same tables, the safety index for each safety problem identified by field surveyors is listed. based on the safety index values shown in table 4, the safety problems can be ranked. the ranking of the identified safety problems is also listed in table 4. after the safety problems were identified and ranked in the research, possibly safety countermeasures were proposed. many low cost countermeasures focused on the intersection design and operation can be both implemented and effective at the local level. when improving an intersection consider some general strategies such as the following: hameed aswad mohammed al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012156 • attempt to minimize intersection conflicts and crashes, and lessen the impacts of crashes when they do occur, • attempt to match a countermeasures to an identified safety problem, • evaluate implemented countermeasures to identify what works and what does not, for consideration at future locations, and • select countermeasures that are technically feasible and practical, and provide an advantageous benefit/cost ratio. practically, a safety problem may have several corresponding countermeasures and one countermeasure may be used to improve several safety problems. the above describes a real application case with the use of the diagnostic approach developed in the research. it is found the approach is relatively easy to be used in fields. as shown in the real application, the approach has good applicability. to effectively use the approach, it is very important for field engineers to complete field surveys to intersections. field engineers should have good field experience and safety judgments. countermeasures to improve intersection safety intersection crashes have many causes including, but not necessarily limited to, poor geometry and design, deficient operational control, insufficient maintenance, and human error. considering all of these elements, the optimal approach to improve intersection safety is multidisciplinary in nature however, many low cost countermeasures focused on the intersection design and operation can be both implemented and effective at the local level [11]. the set of low cost countermeasures for unsignalized intersections is design to increase driver’s alertness to the presence of the intersection and reduce potential conflicts with other entering vehicles. countermeasures have been classified as basic or supplemental. basic countermeasures are those that are usually very low in unit cost and effective in term of reducing future crash potential [3]. there are a number of countermeasures that can be implemented to lessen the adverse effects of intersection hazards. the type of countermeasure depends on the nature of the intersection and the safety concerns apparent at a particular location [14]. the following methods were listed [3, 2, 7, 11, 16, and 17]. provision of adequate sight distance provision of adequate sight distance on approach to and entering intersections, and when turning across oncoming traffic can reduce crash frequency and severity and studies have shown reduction of to 67 percent in crashes where obstructions that inhibited sight distance were removed [7]. each unsignalized intersection contains several potential vehicle conflicts. the possibility of these conflicts actually occurring can be greatly reduced through provision of the proper intersection sight distance. adequate sight distance for drivers at unsignalized approaches to intersections has long been recognized as among the most important factors contributing to overall safety [3]. sight distance at intersection can be improved by clearing obstruction from the required clear zone envelop and more simply by prohibiting on-street parking near intersections and by moving stop lines further back from the intersection threshold [14]. treatment to reduce speed given that speed and speeding is a major contributor to trauma at unsignalized intersections, measures to reduce speeds have great potential to minimize crash frequency and severity. there are a number of ways to manage speed on the approach to intersections including reduction of speed limits, provision of traffic calming measures such as pavement narrowing, installation of refuge islands, and alteration of the road surface ( particularly raising of the surface, and provision of technologies to enhance speed limit compliance) [7, 9]. study of traffic safety evaluation and improvements at unsignalized intersections al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 157 improvement of intersection geometric design reduce the frequency and severity of intersection conflicts through geometric design improvements by provide left/right-turn lanes or offset left/right-turn lanes at intersection; provide by pass lanes on shoulders at t-intersections; provide full-length paved shoulders in intersection areas; restrict or eliminate turning maneuvers by signing, providing channelization, or closing media openings; convert offset t-intersections to 4-legged intersections; use indirect left-turn treatments to minimize conflicts at divided highway intersections, improve pedestrian motorcycle and bicycle facilities to reduce conflicts between motorists and non-motorists [ 2 ]. provision of warning signs these are provided to alert drivers of hazardous conditions that may not be apparent, such as the presence of intersections, particularly those with poor sight distance [8]. call attention to the intersection by installing rumble strips on intersection approaches; provide dashed markings for major road continuity across the median opening at divided highway intersection; provide flashing beacons; provide variable message signs, provide pavement markings with supplementary messages, such as stop ahead; and provide improved maintenance of stop signs [2]. provision of lighting at unsignalized intersections adequate lighting at unsignalized intersection is required to increase visibility of the roadway and its immediate environment at night, thereby enabling drivers to maneuver safety and efficiently through an intersection; in their examination of the effect of installation of street lights at urban intersections on crash risk [7, 9]. improve management of access near unsignalized intersections effective access management is a key to improving safety at and adjacent to unsignalized intersections. a key element of access management is closure or relocation of driveways adjacent to intersections. access points within 75m upstream and downstream of an intersection are generally undesirable. strategies for mitigating safety problems that may arise from a driveway located too close to an unsignalized intersection are to close the driveway (if other access to the adjacent property already exists) or to relocate the driveway (if no other appropriate access is available). when a driveway on a high-volume street adjacent to unsignalized intersection cannot be close or relocate, it may be appropriate to restrict turning maneuvers at the driveway [2]. provide skid resistance in intersection and on approaches slippery pavement should be addressed to reduce the potential for skidding. the coefficient of friction is most influenced by vehicle speed, vehicle tire condition, and surface condition. consideration should be given to improving the pavement condition to provide good skid resistance, especially during wet weather. this can be accomplished by [2]: • providing adequate drainage • grooving existing pavement, and • overlaying existing pavement improve pedestrian, motorcycle and bicycle facilities to reduce conflicts between motorists and nonmotorists improvements to pedestrian facilities that may reduce conflicts between motorists and nonmotorists include: • continuous sidewalks • signed and marked crosswalks • pedestrian signs and markings • sidewalk set-backs • pedestrian overpasses • median refuge areas hameed aswad mohammed al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012158 • intersection lighting some of the problems that cyclists face at intersections include high traffic volumes and speeds and lack of space for cyclists. possible improvement projects include: • widening the outside through lanes or adding bike lanes • providing median refuges at key minorstreet crossings • providing independent cycle / pedestrian structures where necessary • providing smooth paved shoulders provide signalized intersections changing unsignalized intersections into signalized intersections and providing exclusive left-turn or right-turn lane and related signal phasing. conclusion intersections are important connections between two or more roadways and the resulting conflicting traffic movements make intersections crash-prone locations. the safety condition of unsignalized intersections has a great influence on the traffic safety of the road net, and decrease the number of traffic accidents. crash-based safety analysis is unpredictable and randomly happens and it is limited by locations and analysis time period. thus, it needs a long time period to accumulate sufficient crash data and it is difficult to obtain these data and reliability of past data. conflict-based safety analysis can be applied to quantitatively evaluate highway intersection traffic safety. the judgment and determination of traffic conflicts are more subjective nature. different observers may give different traffic conflict judgments. in the research presented in this paper, another approach called diagnostic approach was attempted. in order to evaluate the safety performance of highway intersections more objectively, efficiently, and fast, the existing conditions at unsignalized intersection could be used as the basis for intersection safety performance evaluation. non-crash and non-conflict based evaluation method can give a safety evaluation to roadway facility with a relatively short time period and are relatively easy to be implemented in real applications. this type of approach can be better used by field safety engineers to find potential safety problems and corresponding countermeasures can be achieved with short time period. this research analyzes safety problem and present information on suggest effective, low-cost intersection countermeasures improvement at unsignalized intersections. these low-cost countermeasures can be applied to a large number of unsignalized intersections with a high frequency of crashes. references [1]wu qun, and xiang qiaojun, " traffic safety evaluation of highway intersection with the use of conflict severity concept ", journal of transportation engineering, ieee, 2008, pp. 574-578. [2] transportation research board, “guide for addressing unsignalized intersection collision”, nchrp 500, vol.5, washington, d.c., 2003. [3]yuan li, yuan hewei, and huang zhengzhong, “safety improvement at two-way stopcontrolled intersection ", journal of transportation engineering, ieee, 2010, pp. 252-254. [4]jian lu, li yuan, guoqiang zhang, and qiaojun xiang, “diagnostic approach for safety performance evaluation and improvements of highway intersection ", journal of transportation engineering, trb, 2007 annual meeting cd-rom. 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[9] preston, h., and schoenecker, t., " potential safety effects of dynamic signing at rural horizontal curve ", ( report no. 3-35 ) , d.c.,usa, national co-operative highway research program, 1999. [10]li yuan, and jian lu," safety evaluation method of roadway intersection ", journal of transportation engineering, ieee, 2009, pp. 590-593. [11]federal highway administration, "low cost intersection safety improvements ", u.s. department of transportation, washington, d.c., 2008. [12]xiaoming zhong, and liande zhong, " study on the relationship of intersection design and safety of urban unsignalized intersection in china ", submitted for presentation and publication consideration at 3rd urban street symposium of the transportation research board, washington, 2007. [13]li yuan, jian lu, guoqing zhang, and qiaojun xiang, " safety evaluation approach of highway intersection ", journal of transportation engineering, asce, 2008, pp. 301307. [14]p.b.wolshon, " ite toolbox and intersection design and safety ", the institute of transportation engineers and the federal highway administration, 2004. [15]guoqiang zhang, wei wang, jian lu, and qiaojun xiang "safety performance evaluation of highway intersection based upon traffic flow theories" , journal of transportation engineering, ieee, 2008, pp. 1459-1463. [16]hauer, e., " research into the validity of the traffic conflicts technique " , accident analysis and prevention, vol. 18, 1986, pp. 471-481. [17]sayed, t., and zein, s., " traffic conflict standards for intersections " , transportation planning and technology, vol. 22, 1999, pp. 309-323. [18]yuan, l., lu, j., and xiang q.j., " research on diagnostic method of highway intersection safety ", international road safety seminar, beijing, china, 2005, pp. 348-352. [19]sun, b.y., lu, j., and ma q.l., " research on method for priorities of traffic safety countermeasures at highway intersections " , international road safety seminar, beijing, china, 2005, pp. 341-344. [20] xiang, q.j., lu c., wu q., and, lu j., " traffic safety evaluation on highway intersection based on severity division of traffic conflict " , journal of highway and transportation research and development, 2008, pp. 128-131. hameed aswad mohammed al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012160 [21] institute of transportation engineers, " traffic engineering handbook ", institute of transportation engineers, washington, d.c., u.s., 1999. [22] ma zengqiang, pan cunzhi, and, wang yongqiang, " road safety evaluation from traffic information based on anfis ", journal of transportation engineering, asce, 2008, pp. 554-558. [23] zhu shengxue, lu jian, xiang qiaojun, and, yan linli, " rural road traffic safety diagnosis method " , journal of transportation engineering, asce, 2009, pp. 4037-4042. table 1 survey form for the diagnostic approach survey index severitysignificance low ↔ highlow ↔ high 4 53 42 31 20 14 53 42 31 20 1 survey list 1-inadequate lane width 2-insufficient intersection sight distance 3-complex intersection design 4-improper traffic signs as to number, size, message, placement, and visibility 5-pavement marking faded and poor visibility 6-inadequate curb radius for turning vehicle 7-improper pedestrian crosswalk placement and design 8-vehicle speed too high for existing condition 9-poor pavement skid resistance 10-insufficient lighting al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 table 2 survey result by six different surveyors at unsignalized intersections of f1, f2, and f3 along arterial road poor pavement skid resistance insufficient lightingimproper traffic signsinsufficient intersection sight distance inadequate lane width severitysignificanceseveritysignificanceseveritysignificanceseveritysignificanceseveritysignificance surveyorperiod 3.5244.22.924.8443a 3.71.94.24.432.64.74.13.72.8b 3.92.14.34.73.134.64.24.23.1c 3.11.74.14.42.72.14.94.43.52.6d 3.62.444.62.52544.13.2e 3.92.34.34.52.82.34.84.53.42.9f time 1 3.31.844.12.92.24.84.13.92.8a 3.52.14.14.732.54.543.83.2b 3.924.24.53.12.84.7432.7c 3.41.6442.72.34.84.53.73d 3.72.24.34.82.82.44.74.242.9e 3.52.14.14.72.3254.332.4f time 2 3.62.34.542.424.84.34.13.1a 3.81.84.74.22.82.44.54.23.52.6b 3.724.14.53.22.94.84.33.92.8c 3.21.84.44.22.62.24.74.13.83d 3.42.14.64.32.52.14.84.33.92.7e 3.524.54.62.824.743.72.8f time 3 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 table 3 survey result by six different surveyors at unsignalized intersections of f1, f2, and f3 along arterial road vehicle speed too high for existing conditions improper pedestrian crosswalk placement and design inadequate curb radius for turning vehicle pavement marking faded and poor visibility inadequate intersection channelization severitysignificanceseveritysignificanceseveritysignificanceseveritysignificanceseveritysignificance surveyorperiod 4.53.21.22.2122.51.73.23a 5421.81.32.12.7132.5b 4.13.51.52.51.11.431.63.12.9c 4.73.71.41.71.41.62.91.32.92.7d 4.93.21.82.81.61.73.21.43.43.2e 4.53.422.5122.81.93.23.1f time 1 4.43.6121.31.92.61.73.63.2a 4.93.81.91.61.42.12.62.12.82.6b 4.33.71.82.31.72.23.11.62.92.5c 4.53.81.91.91.21.531.332.7d 4.731.52.21.61.93.41.43.13e 4.43.62.22.31.3231.93.43.2f time 2 4.63.41.42.11.12.22.81.73.53.1a 4.94.12.11.81.622.91.432.7b 4.33.71.721.81.931.63.23c 4.53.51.61.81.51.83.31.33.32.9d 4.53.11.72.11.823.21.432.9e 4.83.422.21.22.23.11.93.53.1f time 3 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 table 4 safety problems and corresponding safety scores for the intersection of f1,f2, and f3 ranktotal scoresaverage score of severity average score of significance problems 14.544.754.191-insufficient intersection sight distance 24.304.244.412-insufficient lighting 34.204.583.543-vehicle speed too high for existing condition 43.413.732.874-inadequate lane width 53.073.172.915-inadequate intersection channelization 62.993.562.016-poor pavement skid resistance 72.612.782.327-improper traffic signs as to number, size, message, placement, and visibility 82.442.951.568-pavement marking faded and poor visibility 91.851.712.19-improper pedestrian crosswalk placement and design 101.571.381.9110-inadequate curb radius for turning vehicle 30.98total hameed aswad mohammed al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012164 figure 1 flow process of evaluation method identification of safety problems significance ranking of safety problems severity benefit cost ratio ranking of possible safety countermeasures selection of an intersection identification of possible safety countermeasures identification of major safety problems determination of safety countermeasure study of traffic safety evaluation and improvements at unsignalized intersections al-qadisiya journal for engineering sciences, vol. 5, no. 2, 150-165, year 2012 165 f figure 2 satellite image for unsignalized intersections in fallujah city (google earth 2011) 11ff 33ff 22ff \(microsoft word \\313\\307\\343\\321 5\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 44 an experimental study to investigate the upper heating and cooling effect on natural convection heat transfer through a horizontal rectangular enclosure tamir k. salim tikrit universitycollege of engineering mechanical department abstract in this study an experimental work has been conducted to investigate the natural convection through a rectangular enclosure fixed horizontally. the upper surface for the apparatus has been heated and cooled. the test apparatus has been manufactured first, and then thermocouples have been fixed in proper positions. then many readings, for temperatures, have been registered for each thermocouple. these readings have been taken for different mass flow rates of cooling water with different heat fluxes. these experiments have been conducted for the range of rayleigh number )10*5ra10*4( 65 ≤≤≤≤≤≤≤≤ , and for the range of water mass flow rates in cooling region (0.009 kg/s≤m& ≤0.04 kg/s). four tests for each mass flow rates of water have been conducted, for each one of them five values of heat flux have been used in heating. it has been noticed that the surface temperature of experiments section increased to approach from heating region and the same behavior of temperature inside the section, with appearance stagnation region and not change of air temperature on center region for the apparatus. the study shows that nusselt number decreases by (50.4 %) in cooling region, and nusselt number value increases by (33%) in heating region as the mass flow rate of water decreases by (77.5%) for the highest and lowest heat flux. also, nusselt number decreases by (57.5%) as the heat flux decreases by (95%) for the highest and lowest water mass flow rate. an experimental correlation has been adopted between average nusselt number against average rayleigh number (ra) for both heating and cooling region is       −−−−++++ 1 303.0 ra 016.01 348.0 . key words: natural convection, rectangular, enclosure, heating and cooling, horizontal . حيز بالحمل الحر خالل تجريبية لبيان تأثير التسخين والتبريد من األعلى على انتقال الحرارةدراسة الشكل مستطيل أفقي مغلق ثامر خلف سالم كلية الهندسةجامعة تكريت .قسم الميكانيك al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 45 الخالصة السطح .مثبت بوضع أفقي الشكل مستطيل حيز مغلقخالل لطبيعيافي هذه الدراسة أجراء تجارب عملية لقياس الحمل تم لقد تم تصنيع جهاز االختبار أوًال ثم تم تثبيت المزدوجات الحرارية عليه بعدها أخذت قراءات متعددة .هوتسخين هتبريد العلوي للجهاز تم .مع تغير الحمل الحراري لماء التبريدمختلفة كتلية تدفقاتوقد أخذت القراءات المذكورة ل. لدرجات الحرارة لكل مزدوج على انفراد )5ra10*4*10(من عدد رايلي أجريت هذه التجارب للمدى 65 من معدل التدفق الكتلي للماء في منطقة لمدىو ،≥≥≥≥≥≥≥≥ s/kg04.0m009.0(التبريد w ≤≤≤≤≤≤≤≤ الحراري في ضفيلليقابل كل منها خمس قيم تدفق الكتلي للماءاختبارات لل أربعةأجريت ). & من منطقة التسخين وبنفس التصرف لدرجات الحرارة بباالقتراتزداد مقطع االختبارلوحظ أن درجة الحرارة لسطح . منطقة التسخين تبين من هذه الدراسة .للجهازر في درجات الحرارة بشكل ملحوظ في المنطقة الوسطية يغتداخل المقطع مع ظهور منطقة ركود وعدم معدل التدفق نقصانمع في منطقة التسخين %) ٣٣(في منطقة التبريد و يزداد عدد نسلت بنسبة %) ٥٠.٤(بنسبة يقل عدد نسلت أن الفيض الحراري بنقصان %) ٥٧.٥(بنسبة يقل عدد نسلت ان ،أيضا. واقل فيض حراري أعلىعند )%٧٧.٥( للماء بنسبة يالكتل معدل يقابل) nu(عالقة تجريبية بين معدل عدد نسلت من هذه الدراسة استنبطت .اءواقل تدفق كتلي للم أعلىعند %) ٩٥( بنسبة  ،عدد رايلي لكال منطقتي التبريد والتسخين وهي      −−−−++++ 1 303.0 ra 016.01 348.0 . .أفقي ،و تسخين تبريد ،مغلق حيز، مستطيل ، طبيعيحمل : الكلمات الدالة nomenclature unit description symbol m2 surface area as m enclosure width b j.kg-1. k-1 specific heat cp watt electrical input power eip m/s2 acceleration due to gravity g w.m-2.oc-1 heat transfer coefficient h ampere (a) electrical current i w.m-1.oc-1 thermal conductivity k m enclosure length l kg.s-1 mass flow rate of water wm& --nusselt number nu --rayleigh number ra --prantel number pr w. m-2 heat generated qg w. m-2 convection heat flux qc w. m-2 radiation heat flux qr watt cooling heat qw oc temperature t volt (v) heater voltage v m axial distance x greek symbols -emissivity ε m enclosure thickness δ al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 46 kg.m-3 density ρ m2 s−1 thermal diffusivity α m2.s-1 kinematic viscosity ν kg.m-1.s-1 dynamic viscosity µ k-1 volume expansion coefficient β = 5.67 × 10-8 w m-2 k-4 stefan-boltzmann constant σ subscripts -cold c -film fl -fluid (air) f -hot h -inlet or (inside) i -outlet o -surface s -water w introduction steady state natural convection from rectangular enclosures and square ducts has many engineering applications in cooling of electronic components, design of solar collectors and heat exchangers. survey of the literature shows that correlations for natural convection from vertical and horizontal plates, vertical and horizontal cylinders, spheres, vertical channels and elliptic cylinders are reported for different thermal boundary conditions. however, limited numbers of experimental studies were concerned with heat transfer through rectangular enclosures and square ducts heated and cooled from above(zeitoun and mohamed, 2005). (al-bahi et al., 2002); had studied numerically laminar natural convection heat transfer in an air filled vertical square cavity differentially heated with a single isoflux discrete heater (heater length/enclosure height= 0.125) on one wall and the opposite wall represented a heat sink with top and bottom adiabatic surfaces. the time dependent two-dimensional conservation equations of mass, momentum, and energy are solved employing a forward time central space implicit finite difference scheme. the streamlines and isotherms for different heater locations (the distance from the heater center to the bottom of the cavity/ enclosure height= 0.25-0.75) and rayleigh numbers (103–106) were obtained. their results showed that for small heaters the flow was characterized by a single circulation cell, which prolonged to an elliptical shape at high rayleigh numbers (106) with distortion towards the location of the heater. at low rayleigh numbers (103–104), heat transfer by conduction was dominating and nusselt number was nearly constant. the conducted that the local nusselt number decreased along the heater length from the leading edge with slight enhancement at the trailing edge. effects of thermo-acoustic wave motion on the developing natural convection process in a compressible gas-filled (nitrogen and helium) square enclosure were investigated numerically by (murat and bakhtier, 2003); the left wall temperature was raised rapidly (impulsively or gradually) while the right wall was held at a specified temperature. the top and the bottom walls of the enclosure were considered thermally insulated. the numerical solutions of the full navier–stokes equations were obtained by employing a highly accurate flux-corrected transport algorithm for the convection terms and by a central differencing scheme for the viscous and diffusive terms. thermo acoustic waves were generated by increasing the left wall temperature of the enclosure impulsively (suddenly) or gradually and rapidity of the wall heating process was observed to be the leading parameter on the strength of the thermo acoustic waves. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 47 (rahman and sharif, 2003); investigated numerically free convective laminar flow of a fluid with or without internal heat generation in rectangular enclosures of different aspect ratios and at various angles of inclination. two principal parameters for this problem were the external rayleigh number which represented the effect due to the differential heating of the side walls, and the internal rayleigh number which represented the strength of the internal heat generation. results were obtained for a fixed external rayleigh number (2×105), with internal rayleigh number (0) (without internal heat generation), and also with internal rayleigh number (2×105) (with internal heat generation).flow patterns and isotherms did not show any significant difference between the cases with and without internal heat generation other than slight shift and changes in stream function and isotherm values as long as the internal rayleigh number was less than or equal to the external rayleigh number. local heat flux ratios along the hot and the cold walls decreased monotonically in the flow direction for a major downstream portion. at certain inclinations the local heat flux ratios increased initially and then decreased. the steady laminar natural convection in air-filled, 2-d rectangular enclosures heated from below and cooled from above, was studied numerically for a wide variety of thermal boundary conditions at the sidewalls by (massimo c., 2003). he used mass, momentum and energy transfer governing equations which was solved by developed numerical model based on the simpler algorithm. the study was carried out for the range of aspect ratio )8a66.0( ≤≤≤≤≤≤≤≤ , and the range of rayleigh number )10ra10( 63 ≤≤≤≤≤≤≤≤ . he found that the heat transfer effectiveness of the bottom wall increased as each adiabatic sidewall, and the heat transfer rate from any heated or cooled boundary surface of the enclosure increases as the rayleigh number increased. while the local heat fluxes from the top and bottom walls are strictly dependent on the thermal boundary conditions. the heat transfer rate from the heated or cooled sidewalls was independent of the thermal configuration of the enclosure. (zeitoun and mohamed,2006); had reported numerical simulations of natural convection heat transfer from isothermal horizontal rectangular cross section ducts in air. their results showed as the aspect ratio increases, separation and circulation occurs on the top surface of the cross section duct at fixed rayleigh number and the corresponding behavior had been observed through the isotherms. they had also obtained a general correlation using the aspect ratio )(γγγγ as a parameter: [[[[ ]]]] 821445.0114.0061.0 10ra700ra371.09.0nu ≤≤≤≤≤≤≤≤γγγγ++++γγγγ==== −−−−−−−− the study of laminar and transition to turbulence natural convection heat transfer from the outer surface of rectangular ducts in air with their axis horizontally, was investigated experimental by (mohamed,2007); five ducts had been used with aspect ratios of 2,1 and 0.5. the ducts heated using internal constant heat flux heating elements. two distinct flow regimes were observed; namely laminar and transition to turbulence. their results showed at low values of convection heat flux and characterized due to decrease in value of nusselt numbers at any fixed longitudinal x station on the duct’s surface, and nusselt number increased as x increased along the duct’s surface for any value of the heat flux. they had also obtained a general correlation of average nusselt numbers by using a parameters, aspect ratio (((( ))))γγγγ , area ratio (((( ))))κκκκ and (ra): (((( )))) 87385.0367.0179.0 10*6ra10*3,,100ra256.0nu ≤≤≤≤≤≤≤≤〈〈〈〈κκκκγγγγκκκκ==== −−−− numerical simulation of turbulent natural convection in a square enclosure with localized heating from below and symmetrical cooling from the vertical side walls were reported by ( sharma a. etal. ,2007), the heat source was considered to be centrally located at the bottom wall with different heated widths, which was assumed to be either isothermal or with isoflux. distributions of streamlines and temperature fields were obtained. the dependence of the nusselt number on the heated width was found to be completely different rot the isothermal and isoflux heating cases. (hakan f. & eiyad a., 2008), studied numerical of natural convection in partially heated rectangular enclosures filled with nanofluids. they used finite volume to solve the governing equation. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 48 the calculations were performed for rayleigh number )10*5ra10( 53 ≤≤≤≤≤≤≤≤ , height of heater )75.0h1.0( ≤≤≤≤≤≤≤≤ , location of heater )75.0y25.0( p ≤≤≤≤≤≤≤≤ , aspect ratio )2a5.0( ≤≤≤≤≤≤≤≤ and volume fraction of nanoparticles )2.00( ≤≤≤≤ϕϕϕϕ≤≤≤≤ . they found the heat transfer increased with increases of height of the heater. also, the heater location affected the flow and temperature fields when using nanofluids. the nanofluids increased with increasing the value of volume fraction of nanoparticles. the enhancement of heat transfer in rectangular enclosures, dependent on the presence of nanoparticles. mathamitical simulation of the transient turbulent natural convection in the rectangular enclosure having finite thickness walls, were studied by (geniy v. etal.,2010), they used the navierstokes equation to solve the turbulence model with wall function. the study was carried out for grashof number )10gr10( 108 ≤≤≤≤≤≤≤≤ , the transient factor )10000( 〈〈〈〈ττττ〈〈〈〈 and thermal conductivity ratio (k1,2=5.7*10 -4, 6.8*10-5). they found that increasing gr is reflected in reduction of a thermal boundary layer thickness, and the increased in transient factor leads to increment in average nusselt number. the decrease in thermal conductivity ratio leads to the diminution of the generalized heat transfer coefficient and increased in average nusselt number. a correlation was obtained between grashof number and average nusselt number is:19.0avg gr*53.0nu ==== experimental work natural convection heat transfer is one of the most important convection transfers so we conduct an experiment natural convection in a rectangular enclosure. a photo (a-1) shows the test section , and fig.(b-1) illustrates the schematic drawing of the test section. a rectangular enclosure made of galvanized iron oriented horizontally is used. the cross section area of enclosure is square, its thickness (((( ))))δδδδ and width enclosure (b) are (10cm), and the length was (100 cm). the dimensions of cooling tank are (10×10×50cm). the active heated length is only (50 cm) and cooling length is only (50 cm). the rectangular surface temperature was measured by (50) thermocouples (t type) which are positioned on all apparatus surface, four thermocouples are positioned for five locations, (2) thermocouples to measure the temperature at the ends the apparatus section and (5) thermocouples in five locations to measure the inside air temperature in the center of the apparatus section, also (2) thermocouples has been used to measure the temperature of the inlet and outlet water from cooling tank. another thermocouple is used to measure the laboratory ambient temperature. the upper surface test section was heated electrically using coil and an electrical resistance on the upper wall of (5m) in length with a resistance ( m/1ω ). to reduce the heat losses the test section is thermally insulated with fiber glass of (10cm) in thickness. the two ends of the apparatus section and other surfaces were insulated electrically and thermally using fiber glass only. the heater was supplied with an alternative electrical power using converter that supplies with a steady voltage through a voltage regulator (220 v). an ameter was used to measure the current pass through the heater with accuracy (10-4 a). the cooling water flow rate can be controlled by two valves for inlet and outlet water from the cooling tank, the mass flow rate of water is calculated by using a (1000 ml) glass container and stop watch. calculation procedures before the experiments test starts, the thermocouples are calibrated using distilled water and crushed ice bath in the range of (0-100)oc. mercury bulb thermometer was immersed together with a thermocouple and water temperature was recorded. sample calibration curve is shown in fig.(2). the laboratory ambient temperature is within the range (15-20 oc). the test procedure can be listed as follow: al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 49 1control the water mass flow rate by inlet valve. 2the test section is set to the proper voltage and this is achieved using a variable transformer. 3after (1.5-2 hr) the system reaches the steady state condition. the enclosure surfaces temperatures, the inlet and outlet water temperatures, the water mass flow rate through the cooling tank, the laboratory temperature and the heater voltage and current have been registered. the heat generated (qg) is dissipating from the enclosure surface by convection and radiation. v*ieip ==== (1) s g a eip q ==== (2) where lb5.0as ∗∗∗∗==== rcg qqq ++++==== (3) where qc and qr, are the fraction of the heat flux dissipating from the enclosure surface by convection and radiation, respectively which can be calculated as (mohamed, 2007): (((( ))))4c4hr ttq −−−−εσεσεσεσ==== (4) where (th and tc) is represented in figre1: th= th1: is the upper surface temperature in heating region for right side. tc= tc1: is the lower surface temperature in heating region for right side. th= th2: is the lower surface temperature in cooling region for left side. tc= tc2: is the upper surface temperature in cooling region for left side. ε is the surface emissivity of the enclosure and it is estimated as 0.3 for galvanized iron (siegel, 1992). the film temperature for the air is calculated using the following equation (holman, 1977): 2 tt t chfl ++++ ==== (5) the characteristic of the air are calculated through the test section which are varied depending on in the film temperature of the air and these are calculated using the following empirical equation (john, 2003): 3 fl 82 fl 5 fl 3 f t10*54786.4t*10*8919.3t10*4715.721003.1 −−−−−−−−−−−− ++++−−−−++++====ρρρρ (6) 3 fl 122 fl 9 fl 64 f t10*662.3t10*836.3t10*285.110*577.1 −−−−−−−−−−−−−−−− −−−−++++−−−−====µµµµ (7) 3 fl 92 fl 6 fl 3 f t10*588.3t10*760.3t10*236.1155.0k −−−−−−−−−−−− −−−−++++−−−−==== (8) 3 fl 92 fl 6 fl 2 f t10*588.3t10*799.4t10*691.1692.2pr −−−−−−−−−−−− −−−−−−−−−−−−==== (9) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 50 3fl 62 fl 3 flpf t10*205.5t10*97.4t627.1885.825c −−−−−−−− ++++−−−−++++==== (10) 3 fl 92 fl 5 fl 3 f t10*99.6t10*143.2t10*362.22315.0 −−−−−−−−−−−− −−−−++++++++−−−−====αααα (11) where the quantity of the heat transfer (qw) from the air in cooling region is calculated as follow (holman, 1977): )tt(cmq iwowpwww −−−−==== & (12) local convection heat transfer coefficient and local nusselt number have been calculated indirectly measured respectively using the following equations (mohamed, 2007): (((( ))))cxxh c x tt q h −−−− ==== (13) k .h nu xx δδδδ ==== (14) then the overall longitudinal average h can calculated as flow (mohamed, 2007): ∑∑∑∑ ==== ==== 5 1x x 5/hh (15) the non-dimensional overall average nusselt and rayleigh numbers are calculated as follow (mohamed, 2007): k .h nu δδδδ ==== (16) (((( )))) νανανανα δδδδ−−−−ββββ ==== 3 cxxh .ttg ra (17) where f f ρρρρ µµµµ ====νννν and flt 1 ====ββββ four tests have been carried out (0.04, 0.02, 0.14 and 0.009 kg/s). water is used to cool the half upper surface. and for each mass flow rate the heat generated is changed (147, 490, 1054, 1708 and 2940 w/m2). the previous test have been repeated ones for each change in water mass flow rate. results and discussions twenty tests had been carried out for each of the following variables. 1. the mass flow rate of water have been varied within the range (0.009-0.04 kg/s) and this was done four times. 2. the heat flux have been varied within the range (147-2940 w/m2 ) and this was done five times. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 51 the effect of mass flow rate on the temperature ratio (the ratio between the top surface temperatures and the temperature of the air in the center of the enclosure) at constant heat flux is shown in figures 3-7. in the cold region this ratio is almost constant no mater what is the mass flow rate at any heat flux. this is happening because the cold air is moving downward and the air in the center of the enclosure is almost has the temperature of the top cold surface, then the temperature ratio rises up as moving toward the hot region because the air can't neither moves downward because it's density is getting lower nor cross the top solid surface, so it moves sideward preferring the cold half side. for these reasons the temperature ratio is increasing and gets it's highest value at (x/l=0.67), this region can be considered a stagnation region. the decreasing in the section apparatus temperature ratio at the end is justified by the heat loss at that region. at a specific heat flux when the mass flow rate increases more heat is convected which decreases the temperature ratio. figures 8-11 show the effect of changing heat flux at constant mass flow rate on the temperature ratio. the same previous general behavior is observed. at a specific mass flow rate as the heat flux increases the top surface temperature in the hot region is getting higher than the temperature of the air in the center of the enclosure which means higher temperature ratio particularly at (x/l=0.67) , then because of the thermal losses from the end the temperature ratio decreases. figures 12-16 illustrates the effect of mass flow rate on local nusselt number (nux) along the enclosure at constant heat flux for each figure. nux distribution suffers from fluctuating along the enclosure. the highest nux value is related to the convection created by the top cooling at ( 33.0l/x ==== ), while the lowest can be observed at ( 67.0l/x ==== ) where the top surface is heated. this means that the lowest heat transfer occurred in this part of the enclosure. referring to the value of nux (nearly equal 1) this region can be considered as a stagnation region, that’s happened because the heat transferred by strong bouncyinduced flows can not be transferred upward so that the heat is rather transferred sideward practically toward the cold region causing high heat convection in this region. all heat fluxes nux distribution has the same behavior. the increasing heat flux will increase the heat convected in the enclosure leading to increase nux. when the mass flow rate decreases at (0.014 and 0.009 kg/s) less heat will be convected at low heat flux (147 and 490 w/m2) and causing convergence nux values in the cold half of the enclosure, as shown in figures 12 and 13. the same general behavior for nux distribution is observed when the heat flux change at fixed water mass flow rate as shown in figures 17-20. as the mass flow rate increases more heat is convected from the hot surface to the cold surface which will cause higher nux for any heat flux, so that at ( 04.0m =& kg/s) witness the highest nux at ( 33.0l/x ==== ), this is because of increasing the heat convected between the coming hot air from the hot region and the cold surface. at ( 67.0l/x ==== ) nux does not affected by changing mass flow rate and it’s still presents a stagnation region. also ,it can be seen at higher heat flux (qg=2940 w/m2) when the mass flow rate decreases at (0.014 and 0.009 kg/s) more heat will be convected at ( 33.0l/x ==== ) causing higher nux value and causing convergence in nux values in the cold half of the enclosure, as shown in figures 19 and 20. the increase of average rayleigh number causes considerable increasing in the average value of nusselt number for different value of heat fluxes. and this was shown in figure 21, this is because of the effect of increasing convected heat as the heat generated increases. the average value of nusselt number is decreasing by (57.5%) as the heat generated decreases by (95%). figure 22 shows the relation ship between the average nusselt number and the average rayleigh number for different values of water mass flow rates. it could be seen that the average value of nusselt number is increasing with the increase of average rayleigh number and this is for all different water mass flow rates, this is because increasing heat transfer coefficient. the average value of nusselt number decreases by (50.4%) as the water mass flow rate decreases by (77.5%), this is because the water gets hotter and the heat transfer reduced and nu will be reduced subsequently. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 52 the case when there is no mass flow rate is chosen to predict the results of present work, as declared in figure 23. in this case since the enclosure is heated from above and there is no fluid flow (nu equals 1) (bejan and kraus, 2003). the maximum difference between the present work and the case above is (19%) which can be accepted. figure 24 compares the regression of the lines and experimental data. the following correlation is obtained for the present data is:         −−−−++++==== 1 303.0 ra 016.01nu 348.0 (18) for )10*5ra10*4( 65 ≤≤≤≤≤≤≤≤ ,with an error band of ( ± 15%) . the comparison between the correlation obtained from equation (18) with reference (bejan and kraus, 2003) is shown in figure 25, it can be seen the error percentage don’t exceed (19 %), which can be accepted. conclusions from this study the following conclusion be deduced:-. 1. the internal temperature increases with increasing the heat flux and decreases with increasing the water mass flow rate. this is because of the phenomenon of separating the cold air to be settled in the bottom and the hot air to be settled in the supreme. 2. a stagnation region is observed below the top heated surface. this happens because the heated fluid always rises up, but since the hot surface is in the top the air can’t move upward and instead it moves sideward. in this case the hot air prefers to move toward the cold region causing the highest heat transferred in the enclosure. 3 the stagnation region and the highest heat transfer region can be observed in the same location in the enclosure at any mass flow rate and any heat transfer flux. 4. increasing the mass flow rate and the heat flux causes increasing the bouncyinduced flow strength which benefits the heat transfer. 5. when ( 0 w m ====& kg/s) the present data has a good agreement with the case of horizontal rectangular enclosure heated from above with no fluid flow. 6. the values of locally nusselt number have its highest values for highest value of water mass flow rate with increases the value of rayleigh number. 7. an empirical relation between the average values of nusselt number with average value of rayleigh number for all cases (equation (18)). references al-bahi, a.m., radhwan, a.m. and zaki, g.m.,"laminar natural convection from an isoflux discrete heater in a vertical cavity,, the arabian for science and engineering, vol.27, no.2c, december (2002). bejan, a. and kraus, a. d., "heat transfer handbook," john wiley & sons, 2003. geniy v. k., mikhail a. s. ," numerical simulation of turbulent natural convection in a rectangular enclosure having finite thickness walls", international journal of heat and mass transfer, vol. 53, pp.163-177, (2010). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 53 hakan f. o. and eiyad a. n.," numerical study of natural convection in partially heated rectangular enclosures filled with nanofluids", international journal of heat and fluid flow , vol. 29, pp.1326-1336, (2008). holman, j. p," experimental method for engineers", mcgrawhill book company, 5th edition,(1977). john h. lienhord iv and john h. lienhord v, " a heat transfer text book", 3rd edition, pp. 714, (2003), http://web.mit.edu/ lienhord. massimo corcione ," effects of the thermal boundary conditions at the sidewalls upon natural convection in rectangular enclosures heated from below and cooled from above", international journal of thermal sciences, vol. 42, pp.199-208, (2003). mohamed e. a.," experimental study of steady state natural convection heat transfer from noncircular metallic ducts", king saud university college of engineering research center, no. 33/426, january, (2007) . murat k. a. and bakhtier f.i.," numerical simulation of developing natural convection in an enclosure due to rapid heating", international journal of heat and mass transfer, vol. 46, pp.2253-2261, (2003). rahman, m. and sharif, m.r.," numerical study of laminar natural convection in incline rectangular enclosures of various aspect ratios," numerical heat transfer, part a, vol. 44, pp. 355-373, january (2003). sharma a.k. , velusamy k., balaji c., "turbulent natural convection in an enclosure with localized heating from below", international journal of thermal sciences, vol. 46, pp.1232-1241, (2007). siegel, r. and howell, j. r.,"thermal radiation heat transfer," mcgraw-hill,new york, 3rd edition ,(1992). zeitoun, o. and mohamed a.,"natural convection heat transfer from isothermal horizontal rectangular ducts,"alexandria engineering journal, vol.44, no.5, pp.695-704, september (2005). zeitoun, o. and mohamed a, "numerical investigation of natural convection around isothermal horizontal rectangular ducts," numerical heat transfel, part a, vol.50, pp.189-204, (2006). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 54 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 55 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 56 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 57 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 58 تصميم قارن مطاطي من خلال تدوير ألإطارات 2012 لسنة 67-52 الثاني، ددالع الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   أإلطارات تدوير خالل من مطاطي قارن تصميم سلمان هادي حسن حسين علي تحسين. د نجف -التقنية الكلية/مساعد مدرس نجف -التقنية الكلية          السيارات تقنية هندسة قسم السيارات تقنية هندسة قسم     موجزال   مشاكل من مهمة مشكلة تسبب والتي المستهلكة المطاطية اإلطارات من االستفادة إلى الحالي البحث يهدف إطار مليون 2 من أكثر العراق في منها يقدر حيث منها للتخلص وجهود إلىأموال تحتاج والتي البيئة تلوث استخدام إعادة جوانب أحد امثلو بشكل استغاللها تم لو مهمة ثروة يشكل اإلطارات من لعددا وهذا سنويا يأخذ لم الجانب وهذا والهندسية الصناعية المجاالت في منها االستفادة يمكن أجزاء تصنيع هو اإلطارات .االهتمام من األخرى الجوانب أخذته ما بقدر الباحثين قبل من كافيا اهتماما استخدامها واقتراح المستعملة ألجزاءاإلطارات الميكانيكية الخواص إلى التطرق تم البحث هذا وفي الصغيرة المولدات في التوليد براس الداخلي االحتراق محرك يربط الذي القارن مثل هندسية كأجزاء الخواص في كبير فرق هناك ليس انه إليها التوصل تم التي النتائج بين ومن الكهربائية للطاقة والمتوسطة للقطع ألالزمة القوة كانت الشد اختبار ففي الجديدة اإلطارات و المستعملة اإلطارات أجزاء بين الميكانيكية بينهما الفرق سبةن فكانت نيوتن 113.27 المستعملة اإلطارات أجزاء في بينما نيوتن 137 الجديدة األجزاء في اقتراح تم وقد القارن عمل على ملحوظ بشكل يؤثر ال وذلك االستعمال تيجةن التقادم إلى يعود وذلك 17% القص معامل قيمة اعتمدت المستعملةحيث اإلطارات من أجزاء يستخدم مرن قارن لتصميم حسابي نموذج أو واحدة بطبقة اربعة القارن منها يتكون التي الشرائح عدد فكان )106n/m2*3.82( العملية التجارب من .)(30kw قدرة ذو محرك مع بطبقتين تينشريح tire recycling as a tool for manufacturing rubber coupler dr. tahseen a. hosain hassan h. salman technical college / najaf technical college / najaf abstract the paper aimed to use the old rubber tires which causing a big problem to the environment and its need much money and efforts to disposing it safely. in iraq there is more than 2 million used tires disposed to the environment yearly whereas in the us there is 2 billion one. سلمان هادي حسنو حسين علي سينتح. د one of the tyre recycling methods , is the use of tyre plies to produce a new rubber parts used in the engineering and industrial purposes as the bridge and machine dampers , this trend of recycling doesn’t take a sufficient care comparing with the other methods . in the current research the study focusing on the mechanical properties of the used tyres and comparing them with the new one , and suggesting a new method to use the recycled tyres as an engineering parts ( for example the coupler lied between the ic engine and the generating head in the generators . one of the results obtained from the experiments, there is no significant difference between the mechanical properties of the old and new tyres , (in the tensile test – the breaking force of the tensile specimen of the new tyre is 137 n and for the old one is 113.27 n , but they are same in the elongation) . a dimensions of a flexible coupling suggested as a computational example and when using the experimental value of shear stress for the cord-rubber composite lamina (3.82*106n/m2)the calculation showing that the number of strips for the coupler should be two with 2 ply lamina or 4 with one ply lamina at engine power less than 30 kw . keywords: tyre recycling , rubber coupling , rubber properties :الرموز e1    .الطولي المحور في المركبة للطبقة يونك معامل                           e2    .العرضي المحور في المركبة للطبقة يونك املمع   ν12بايسون معامل)poisson's ratio( المستوي في) 2-1. ( .) 2-1( المستوي في القص معامل    g12   d        .االلياف قطر t .وااللياف المطاط من المركبة الطبقة سمك ec .لأللياف يونك معامل er .للمطاط يونك معامل vc   .المركبة الطبقة في لأللياف الحجمية النسبة vr .المركبة الطبقة في للمطاط الحجمية النسبة gc .لأللياف القص معامل gr .للمطاط القص معامل e .الطول وحدة في النهايات ددع    f .االمان معامل  τ .للشريحة القص إجهاد  t .القارن له يتعرض الذي العزم   al .المركبة الطبقة في للقص المعرضة المساحة  'n,nعدد الشرائح . 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   53 أإلطارات تدوير خالل من مطاطي قارن تصميم   المقدمة متوسطة مركبة لكل إن افترضنا ولو األنواع مختلفة مركبة مليون 750 أل يقارب ما اآلن العالم في يوجد 50000 وهو افتراضي عمر اإلطارات لهذه وأن الخدمة في تعمل أطار مليارات ثالثة هناك فان إطارات ستة العدد هذا يذهب أين هو اآلن والسؤال . سنوات الثالث تتجاوز ال فترة بعد يتقاعد سوف العدد هذا فان لذا كم اإلطارات من طن مليون 32 ماقدره تشكل اإلطارات هذه؟؟ سنويا يتكرر سوف والذي اإلطارات من الهائل لها يلتفت لم طائلة ثروة تعتبر لكنها بحرقها أو بدفنها إما منها التخلص ويتم الطبيعة إلى ينبذ سنويا المستعملة 1983 ،صباح .احد إعادة لصناعة ةنوا تتكون وبدأت المستعملة لإلطارات المادية القيمة إلى تنتبه الدول بدأت قريب زمن منذ اإلطارات من االستفادة طبيعة لتحديد تتوالى االبحاث أخذت األخيرة السنوات وفي tire recyclingاإلطارات .المستعملة :يأتي كما هي المجال هذا في الرئيسية واالتجاهات أجلها من صنع التي الوظيفة غير لوظيفة استخدامه أو له الحيوية بإعادة إما الكامل اإلطار استخدام -1 .عمره انتهاء بعد ) .الخ..... ، مكونات ، طبقات ( اإلطار من أجزاء استخدام -2  )www.wastonline .org.uk, 2007(.الطاقة مصادر من كمصدر اإلطار استخدام إعادة -3 القوارن وخاصة الميكانيكية األجزاء بعض ناعةص في اإلطارات تدوير استخدام يتضمن الحالي والبحث  المطاطية   اإلطار مكونات تحتوي شعاعي أو متقاطع بشكل النسيجية األلياف من بطبقات المعزز المطاط من حاوية هو الهوائي اإلطار أحيانا وهي مناسب بضغط المضغوط بالهواء تمأل الحاوية تلك األنواع بعض في داخلي مطاطي أنبوب على المنقوش المطاط من بطبقة مغطى الحزام ذلك المعدنية غير أو المعدنية األلياف من بحزام محاطة كونت .اإلطار وظيفة يناسب بشكل الصناعية بالخيوط اآلونةاألخيرة في واستبدل بالمطاط المعامل النسيج من طبقات عدة من اإلطارات تصنع على الهيكل و الواقي الغالف بين يوضع و .عالية بمتانة تمتعي أنه حيث أوسع بنطاق) الرايون ، النايلون( من الهيكل على تحافظ وسادية طبقة – بالمطاط المعامل النسيج من بينية طبقة الخارجي الغالف محيط طول الوسادية الطبقة الحديثة اإلطارات تصاميم بعض في وتصنع لإلطار الواقي الغالف من إليه المنتقلة الضربات . أطول وعمر أعلى متانة لإلطار يضمن مما المعدنية ألسالكا من األلياف طبقة توضع ثم ومن أيضا بالمطاط المعاملة األلياف طبقات من الداخلية األنبوبة ذو اإلطار يتركب من المصنوعة الكسوة أما . بالمطاط الفراغ يمأل ثم بينها فيما المسافات يقومبخفض خاص جهاز في هذه ) . الفلكنة (والتسخين الكبس تشمل بعملية مكانها في تثبت فأنها أنفا المذكورة الطبقات تغطي التيو المطاط 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  54 سلمان هادي حسنو حسين علي سينتح. د األلياف طبقات عدد ويتفاوت المطلوب حسب مواصفات ذو وجعله المطاط تشكيل على العملية هذه وتعمل سيارات تحتوي حين في طبقات أربعة على تحتوي الخاصة السيارات فإطارات اإلطار عمل طبيعة باختالف إطارات في يوجد وكذلك) طبقة 14 (حوالي على ) الكبيرة الركاب سيارات (واألتوبيسات الثقيلة النقل الغرض منالمطاط المصنوع الخارجي للمداس مختلفة أشكال وهناك ، )طبقة 32( األراضي تسوية مركبات مبين يدعى بما مزودة الحديثة اإلطارات بعض وتصنع.االنزالق وتقليل الحركة نقل تحسين منه استهالك بسبب ملم1.6 إلى مساوية المداسوتصبح نقش مجاري تقل وبعدأن (wear indicator)االستهالك التآكل درجة إلى لإلشارة ملم 12 منها واحد كل عرض عرضية أشرطة ستة وجهه نالحظعلى الواقي الغالف  1983 ،صباح. اإلطار منها يتكون التي الطبقات بين األهمية حيث من األولى بالدرجة وتأتي :tread)( لألرض المالمس الجزء طبقة .1 تكون والتي اإلطار دوران إثناء للطريق مالمسة تكون التي الوحيدة المنطقة أجزاءاإلطاراألخرىألنها )(rolling resistanceالتدحرج مقاومة تقليل وعنwet grip)( الرطب الجو في الطريق مسك عن ولةؤأيضامس ) (heat accumulation الحرارة وتراكم )wear( الميكانيكي التآكل ظروف إلى ذلك جراء من تتعرض وقد   .المحيطة الجوية والظروف تغلف المطاط مركب طبقة عن عبارة هي:) breaker bandage (الداخل من لألرض المالمس الجزء طبقة .2 .منه سمكا وأقل مرونة أكثر وتكون لألرض المالمس اإلطار لجزء الداخلي الجزء هذه تغلف . اإلطارات بعض في طبقة من أكثر وتكون :)ply topping( بالنسيج كساءاال مطاط طبقة .3 .الداخلية جدرانه فتغلف اإلطار جانبي إلى تمتد ثم المسلح المطاط أسفل الطبقة اإلطار لجزء المغلفة الطبقة تحت وتقع :)steel cord topping breakers( باألسالك المسلح المطاط طبقة .4 .لإلطار الشد مقاومة زيادة لغرض معدنية بأسالك مسلحة مطاطية طبقة عن عبارة وتكون لألرض المالمس تصلت الجانبية اإلطار لجدران الخارجي الجزء تمثل التي الطبقة وهي :)side wall( اإلطار جدار طبقة .5 جيدة مرونة ذات فتكون األسفل من )bead( والكعب األعلى من )tread(لألرض المالمس اإلطار بجزء .مناسب وسمك المعدنية األسالك من حزمة حول دائري بشكل وتحيط -) :bead wire coating (الكعب تغليف طبقات .6 الدوالب اإلطارعلى تثبيت يفتهاوظ )ring( حلقات بدور الطبقات تلك وتقوم والتسليح التقوية لغرض )wheel.( متوسطة مطاطية مادة من الشكل مثلثة صغيرة طبقة هي :)bead apex( الكعب حشو طبقة أو جزء .7 الواطئة والمرونة العالية الصالدة ذو الكعب وبين جهة من المرنة اإلطار جدران بين بالربط تقوم المرونة .ثانية جهة من 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   55 أإلطارات تدوير خالل من مطاطي قارن تصميم   المطاطي لألنبوب احتوائه تسهيل لغرض الداخل من اإلطار وتغلف :)inner liner (الداخلي التغليف طبقة .8 [ جيدة االستطالة على قابليته مرن مطاطي مركب من وتتكون األخرى الطبقات مكونات بأحد يخدش أن دون [parkash , 2007 1 رقم شكل كيميائيا مستقر حدمو واحد تركيب لتكون بعضها مع جيد بشكل تندمج أن يجب األجزاء هذه وإعادة استعمال بين مفارقة تشكل وهذه أفضل اإلطار أداء كان أكبر الطبقات هذه بين االلتصاق كان وكلما إعادة وفي اإلطار أجزاء بين اكبر والتصاق اندماج إلى نحتاج االستعمال في حيث اإلطار استعمال إعادة يمكن حتى البعض بعضها عن اإلطار ألجزاء كامل فصل وهو العكس يكون أن ينبغي االستعمال . استعمالها الخيوط من عادة المكونة النسيجية والطبقات ، الفوالذية األسالك ، المطاط من أساسي بشكل اإلطار ويتركب النموذجية المكونات يبين 1 رقم الجدولو ، بالمطاط مكسية وتكون ) القطن أو نايلون ،رايون ( الصناعية .طارلإل المستعملة اإلطارات استخدام إعادة :رئيسيين قسمين إلى صالحيته انتهاء بعد اإلطار استخدام إعادة عملية تقسيم يمكن ) non – destructive( تدميري غير : األول القسم هذاو حرق أو تقطيع من عليه تغيير إجراءإي دون الطبيعي شكله على اإلطار من االستفادة به ويقصد :منها استخدامات عدة في إجمالها يمكن عديدة استخدامات له القسم بواسطة لألرض المالمس اإلطار سطح طبقة نقش الطريقة بهذه يتم : ) tyreregroving( اإلطار نفس إعادة -1 الحمل سيارات مثل الكبيرة السيارات إطارات في يحصل وهذا ، الموجودة النقشات وتعميق حفرها   .صاتوالبا خارجية بطبقة للفلكنةوإكسائها القابلة اإلطارات في ذلك ويكون : ) tyre remolding( اإلطار قولبة إعادة -2   .القديمة الطبقة تأكل عند جديدة على اإلطارات وضع الحالة هذه في يتم: ) ( using tyres in seaportالموانئ في كامل بشكل اإلطار استخدام -3 بحافات االرتطام من الناتجة السفينة جدران تلف من يقلل حتى السفينة جدران على أو الموانئ حافات   .الموانئ لتقليل السباق حلبة طول على اإلطارات من مجموعة وضع يتم حيث : والدراجات السيارات سباقات حلبة -4 من المكونة اجزبالحو وارتطامهم المسار عن خروجهم عند أوالدراجات السيارات لسائقي أضرار حدوث   . اإلطارات   2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  56 سلمان هادي حسنو حسين علي سينتح. د destructive ) ( تدميري : الثاني القسم لالستفادة أخرى كيميائية أو ميكانيكية عمليات إلى يحتاج ألنه األول النوع من تعقيدا أكثر النوع هذا يكون من التدوير إعادة يكون أن ويمكن ومتعددة كثيرة النوع هذا واستخدامات مكوناته أو شكله تغيير بعد منه -:* خالل شحذ طريق عن مختلفة بأحجام مطاطي ركام إنتاج يتم العملية هذه في : )grinding( اإلطارات شحذ -1 كما رطوبة كمانع ويستعمل ، الفرش تحت وكذلك المالعب أرضيات في يستعمل الركام ذلك . اإلطارات واسع لمدى وتحمل اكبر مرونة الشارع يمنح يثح الشوارع أكساء في اإلسفلتية الخلطات مع بكثرة ويستخدم   .لألكسدة عالية ومقاومة الحرارة درجات من )80-( دون تبرد ثم شرائح إلى اإلطارات تقطع العملية هذه في : )cryogenic( المفرط التبريد مع الطحن -2 مسارات في الناتجة المطاط حبيبات تستعملو . مكوناتها لفصل الشرائح تطحن مطرقة وبواسطة مئوية درجة على للحصول المطلوبة الطاقة وتعتبر . اإلسفلتية الطرق أكساء في وكذلك األرضيات وتحت المالعب   .نسبيا قليلة المنخفضة الحرارة درجات على للحصول وحراريا كيميائيا المفلكن المطاط يعامل العملية هذه في : ) de-vulcanization( الفلكنة إعادة -3 الناقلة األحزمة صناعة في وكذلك ثانية مرة اإلطارات صناعة في يستخدم والذي مفلكن يرغ مطاط التي(reclaimeter) المرجل الطرقطريقة هذه إحدى ومن العملية هذه فيها تتم طرق أربعة وهنالك. واألحذية   .الشائعة الطرق إحدى تعتبر بناء تم الطريقة هذه في : ) advance molecular agitation technology amat (يفالمايكرو تكنولوجيا -4 تكون الطريقة هذه في ، األصلية مكوناته إلى اإلطار إلعادة يف المايكرو تكنولوجيا يستخدم لمعمل نموذج .سنويا اإلطارات من طن 2000 النموذج لهذا اإلنتاجية الطاقة وتبلغ يمكن ما اقل المخلفات ميكانيكية بطرق لإلطار المكونة الطبقات من طبقة كل فصل يتم حيث : ) ply separation( الطبقات فصل -5  :أهمها كثيرة ميادين في منها واالستفادة أحجام إلى تقطيعها ثم ومن اإلطار طبقات فصل يتم حيث : ) rubber washers ( مطاطية واشرات صناعة أ   . )plate and nut ( الربط أجزاء بين كحشوات تخدموتس ، الطلب حسب مختلفة تستخدم وكذلك واألرصفة المالعب ساحات رصف في تستعمل : )rubber belts( المطاطية األحزمة صناعة ب   . الناقلة األحزمة في العلف ثلم عادة الجافة المواد مناولة في وتستخدم : ) rubber containers( المطاطية الحاويات صناعة ت   .الخ.... الحيواني الجسور تحت الوسائد هذه وتستخدم : ) machine vibration isolation or damper ( االهتزازات لتقليل وسائد ث  www. wast online .org. uk ,2007 . االهتزازات وامتصاص لتقليل الطاقة تخزن التي هيدروكاربونات %60 من أكثر على اإلطار يحتوي : )energy recovery( الطاقة إنتاج -6   :منها مختلفة بطرق توليدها يمكن حيث 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   57 أإلطارات تدوير خالل من مطاطي قارن تصميم   -500 (حرارة بدرجة حراري تحليل عملية وهي : )pyrolysis process( األولية المواد إلى التحليل طريقة أ والزيت غازاتال من خليط فيتولد كامل بشكل الكيميائية األواصر تكسير فيها يتم الهواء عن بمعزل م ْ )900 هيدروكاربونية وغازات ، بيوتلين ، بيوتان ، بروبلين ، االثلين من خليط فهي الغازات أما ، الصلبة والمواد أسود ، الفايبركالس مثل مواد منها األكبر النسبة فتشكل األخرى المتبقية المواد أما الجزيئي الوزن منخفضة ) والفوالذ الفايبركالس (الالعضوية المواد عن الكاربون سودا فصل ويتم أخرى وغازات ، فوالذ ، الكاربون توليد في أعاله المذكورة الغازات وتستعمل المطاطية الصناعات في الكاربون اسود استعمال يعاد حيث ] paul , 1999.[ الطاقة كمصدر اإلطار الاستعم أعادة في الشائعة الطرق منtire – derived fuel) ( كوقود اإلطارات حرق طريقة ب الفحم من بدال بالطاقة األسمنت صناعة معامل جهيزلت أجزاء شكل على أو بكامله اإلطار حرق ، للطاقة . الصلبة والمخلفات ما فأن الصلبة المخلفات أو الفحم من عليها نحصل التي تلك مع اإلطارات من المستخلصة الطاقة وبمقارنة ، الصلبة المخلفات من يتولد مما %300 و الفحم من يتولد ما %125 يساوي الطاقة من اإلطارات تولده   .الكهربائية الطاقة توليد في اإلطارات استخدام يمكن وكذلك   تدويرها المعاد اإلطارات ألجزاء الميكانيكية الخواص على تحتوي يالت المداس منطقة فمثال اإلطار من المأخوذة العينة موقع باختالف الميكانيكية الخواص تختلف الجدار منطقة تكون بينما عالية شد مقاومة ذات تكون المداس تحت إلىطبقات إضافة األساسية الطبقات ألجزاء الميكانيكية الخواص عن كثيرة دراسات أجريت وقد للكلل مقاومة وأكثر مرونة أكثر الجانبي ) .اإلطارات سكراب (تدويرها المعاد اإلطارات الميكانيكية الخواص ايجاد يمكن ذلك عند مركبة مادة هو االطار طبقات من جزء اي نا اعتبرنا واذا وااللياف المطاط من تتكون المركبة المادة فان االطارات وفي المركبة المادة تشكل التي المواد اساس على : من بكل تتمثل والتي مفردة لطبقة للمرونة المستقلة الثوابت ولحساب 2 رقم شكل  . e1 الطولي المحور في )young modulus (يونك املمع -1   .e2 العرضي المحور في يونك معامل -2   .12ν)  21( المستوي في ) poisson ,s ratio( بايسون معامل -3 .g12 ) 21 ( المستوي في )shear modulus( القص معامل -4  يكون ذلك عند        (1) 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  58 سلمان هادي حسنو حسين علي سينتح. د   من مرة) 1000-100( ب اكبر لأللياف يونك معامل فان وااللياف المطاط من المركبة المواد من كثير في   :يلي كما )1( المعادلة تقريب يمكن لهذا للمطاط يونك معامل (2)  فان 2-1 باتجاه للتحميل ) 12ν ( بايسون معامل لحساب (3) على موصولين نابضين العينة اعتبار يمكن )transvers direction( العرضي االتجاه في ونةالمر ولحساب  :التوالي  : فان لذا erec<<والن    shear modulus (g12( القص معامل احتساب يمكن الطريقة وبنفس   قبل من وااللياف المطاط من المركبة للمواد الميكانيكية الخواص لحساب اقترحت العالقات من العديد وهنالك  s.klark, akasaka-hirano,gough-tangorra. (asaad , 2006( الباحثين من العديد westerberg and macsik,2001; astm,1998 ; drescher and newcomb( من كل بين وقد 1994; edil and bosscher, 1992; humphrey, et al., 1993 and huphrey and manion, 1992) إن يستمر وعندما كبيرة بدائية تشققات إلى تؤدي )shreds( اإلطارات أجزاء على المسلطة الصغيرة االجهادات .6 الشكل في مبينة النموذجية والنتائج .يقل العمودي مقداراالنفعال فإن رتفاعباال اإلجهاد اإلطار من العينة موقع هو األول اثنين بمتغيرين تحديده فيمكن ألجزاءاإلطارات القص إلجهاد بالنسبة أما طبيعة يحدد ينةالع موقع فان وفيزيائيا . ɸ الداخلي االحتكاك زاوية هو الثاني والمتغير) االلتصاق قوة( 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   59 أإلطارات تدوير خالل من مطاطي قارن تصميم   في كما المباشر القص فحوصات من المختبرية النتائج وتبين . الجزيئات بين للتجاذب الفيزياكيميائي االرتباط حول دراسات أجريت وقد . المباشر القص نتائج و الجزيئات حجم بين قوي ارتباط هنالك ليس انه 8  الشكل ,wu, benda and cauley( بها قام التي )triaxial tests (المحاور ثالثية اختبارات خالل من القص مقاومة 1997 and benda, 1995( العمودي وباالتجاه عليها مسيطر أحمال العينة على تسلط االختبارات هذه وفي .فقط وإزالة التحميل طوري خالل من بها التنبؤ يمكن المستعملة اإلطارات ألجزاء الديناميكية للخواص بالنسبة التحميل ةإعاد خالل العمودية االنفعاالت فان المستعملة اإلطارات من شرائح على ذلك تطبيق فعند التحميل مبين وكما humphrey , et.al 1993)( قبل من سجلت كما %12 كانت ) الدورية االنفعاالت (الشد وإعادة بين مساحة هناك إن يبين أعاله والشكل . آخرين باحثين قبل من سجلت مشابهة نتائج وهناك 7 الشكلب المساحة تلك فان الطبيعي ومن المطاط في الهسترة ظاهرة إلى تعود المساحة تلك التحميل وإزالة التحميل الجزء حرارة درجة ارتفاع على ينعكس أيضا وذلك صحيح والعكس اقل المتخلفة الطاقة كانت صغرت كلما مع مقارنة قليلة اإلجهاد من حدود في الجزء ذلك تلف إلى يؤدي بالتالي المتخلفة الطاقة فزيادة االختبار تحت من أجزاءديناميكية تصميم لدى واضحا ذلك تأثير ويظهر . اقل المتخلفة الطاقة فيها تكون التي الحاالت بينما المولدات في الداخلي االحتراق محرك مع التوليد رأس تربط التي القوارن مثل المستعملة اإلطارات المكائن وأسس الجسور يف تستعمل التي التخميد وسائد مثل الثابتة األجزاء مع قليال ونيك ذلك تأثير )(machine foundation. القوارن من األنواع هذه في و. 3 رقم شكل إطار شكل على يكون المرن الجزء فان قوارناإلطارات في   بحدود المتوازية االستقامة عدم كذلكو° 4 بحدود والمنقاد القائد بين االستقامة عدم على التغلب يتم ملم3 عمر من تقلل عالية إلىإجهادات بالتالي تؤدي والتي األحمااللصدمية عائمةإضافةإلىتقليل كنهاية ويعمل وان الصدمات تلك ليمتص الكفاية فيه بما صامدا القارن في المرن العنصر يكون أن يتطلب الماكنةوذلك  baker,2003. والمنقاد القائد من لكل سلسة األحمال بجعل يقوم القوارن هذه في اإلطار : )tyre coupler(اإلطاري القارن مكونات  )3 (الشكل ). المطروق الفوالذ من او صب حديد ( الضغط وقرص الطارة -1   ).التثبيت مسامير ( البراغي -2 االطاري القارن ويوجد، irh 70 ± 5° للمطاط الصالدة ) الرايون بخيوط المدعم المطاط من وهو ( اإلطار -3 تختلف وبإبعاد ) 5500rpmإلىrpm 900 من وبسرع kw 12500إلىkw 15( من تمتد القدرة من مختلفة لقيم gitin , 1995 .المطلوبة والسرعة المنقولة القدرة اختالف مع المقترح التصميم 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  60 سلمان هادي حسنو حسين علي سينتح. د  flexible coupling المرنة القوارن من المقترح القارن يعتبر من طبقات من المرن العنصر ويتكون   يكون اإلطاري القارن ففي المرن العنصر حيث من اإلطاري القارن عن يختلف وهو المستعملة اإلطارات القارن يحتوي بينما النايلون أو الرايون بألياف المعزز المطاط من كامل أطار شكل على المرن العنصر بعرض و المستعملة اإلطارات من المنزوع المطاط من أشرطة من مكون مرن عنصر على المقترح بواسطة الصليب أو الشريط من كل ويثبت 4 الشكل في كما صليب شكل على المنقوألو الحمل مع يتناسب . المولد أوفلنجة المحرك دوالب من كل إلى لوالب بواسطة مباشرة أوpressure disc الضغط أقراص (t) الشريط سمكx(w)العرض= الشريط مقطع ( أيضا المنقول الحمل على الصليب أو الشريط سمك ويعتمد المرن العنصر تحمل فأن أكثر أو اثنين يكون اإلطاركأن طبقات من محدد عدد على يحتوي السمك أن وحيث تحديد يمكن بينما . المرن الجزء في المستعملة الطبقات عدد على يعتمد الديناميكية القصو الشد لقوى :يأتي وكما التصميمية الجداول من للقارن األخرىاألبعاد )(generator كهربائي ومولد ) ic engine ( داخلي احتراق محرك بين يوضع مرن قارن : حسابي مثال 4 تشغيل وبمعدل hr/day 10 قدره يومي استعمال بمعدل rpm3000 وبسرعة kw 30 للمحرك االسمية القدرة .م°)50-30( ةحرار وبدرجة الساعة في مرات nominal power = 30 kw design power = nominal power * f1 * f2 * f3 f1 = minimum factor of safety for types of duty . f2 = factor of safety for daily operation . f3 = factor of safety for frequency of start . from tables : (f1 = 1 , f2 = 1.12 , f3 = 1.09 ) then : design power = 30 * 1 * 1.12 * 1.09 = 37 kw . power in kw / speed in rpm ratio pkw/rpm . is = = 0.01233 kw/rpm. kw / 100rpm = 1.233 kw / 100rpm . from tables : the dimensions suitable for the coupling have kw / 100rpm. > 1 and < 2.1 are as follow . torque n.m = 150 n.m mass speed = 3200 rpm bore in minimum rough= 30 mm bore in maximum rough = 55 mm a = 212 mm , b = 95 mm , c = 169 mm , d = 157 mm , e = 83 mm , f = 56 mm , g = 45 mm . . 3 رقم الشكل في كما )a , b , c , d , e , f , g( األبعاد من مكونة واحدة لشريحة القص اجهاد فأن المستعملة االطارات من حشرائ من اطاري قارن استخدام وعند :يكون سوف متر )x 0.002 0.1( مقطع مساحة ذات واحدة طبقة   2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   61 أإلطارات تدوير خالل من مطاطي قارن تصميم   τ = = 7.07 * n / m2 n/m2 106 * 3.82.هي وااللياف المطاط من المركبة المواد من لطبقة g القص لثابت التجربية القيم ومن saad.2006 :هي القارن في استعمالها ينبغي التي الشرائح عدد فأن ǹ = = 1.845 ≈ 2  :)f = 2 (أمان عامل اخذنا ولو n = f * ǹ = 2 * 2 = 4 .منها لكل بطبقتين شريحتين من يكون ان وباإلمكان واحدة بطبقة شرائح أربعة من القارن يكون وبهذا والمقترحات االستنتاجات الكثير قبل من كبير باهتمام ) اإلطارات تدوير ( المستعملة طاراتاإل استخدام حظي األخيرة اآلونة في حدود في يزال ال ميكانيكية أجزاء صناعة في المستعملة اإلطارات استخدام أن إال والمنظمات الدول من البحث خالل من تبين وقد ، جديدة خام مواد من أجزاء لصناعة المنتجين من الكثير ميل بسبب وذلك ضيقة :يلي ما اإلطارات في عليه عما كبيرة بدرجة تتغير لم المستعملة اإلطارات لشرائح الميكانيكية المواصفات أن -1 .الجديدة   .نيوتن113.27 حدود في المستعمل لإلطار  (breaking force) للقطع الالزمة القوة كانت -2  . 5 رقم الشكل يبينه كما% 17 بنسبة تنخفض حيث نيوتن 137 الجديدة لإلطارات القطع قوة كانت -3 محرك من كل يصل مرن مطاطي قارن تصميم في المستعملة اإلطارات استخدام نقترح البحث هذا في -4 في 4 °إلى تصل مرونة يعطي حيث والمتوسطة الصغيرة المولدات في التوليد ورأس الداخلي االحتراق عدة من مكون المستعملة اإلطارات من شريط خداماست ولدى ، المحاور انحراف في ملم 3 وبحدود االستقامة وعند .وحده المطاط تستخدم التي المطاطية القوارن مع مقارنة أطول بعمر يمتاز فانه مرن كقارن طبقات بطبقة أشرطة اربعة تساوي أنها وجدkw 30  من أقل قدرة ذو محرك يربط لقارن الطبقات عدد احتساب   .واحدة   المصادر  وتصميم طبع ،1ط ، 1 ج،الحديثة التكنولوجية والتطورات السيارات ميكانيك ، حسن طفىمص صباح .1   .1983،بغداد،العسكرية المطابع   2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  62 سلمان هادي حسنو حسين علي سينتح. د 2. asaad , m.c , mechanics of cord – rubber composite material, in " the pneumatic tyre" , national high way and traffic safety administration , 2006 , pp 105-185 3. baker, thomas e. evaluation of use 0f scrap tires in transportation related applications in the state of washington, report to the legislature as required by shb2308, washington state department of transportation, 2003 . 4. gitinmaitra& l v prasad , hand book of mechanical design , 2nd ed., tata mcgraw-hill publishing , new delhi ,1995 . 5. humphry, d.n., sanford, t.c., cribbs, m.m.andmanion, w.p., shear stress and compressibility of tire chips for use as retaining wall backfill. rtransportation research record 1422, washington, d.c., 29-35, (1993). 6. parkashvenkataraman, effect of nitrogen on rolling resistance and vehicle fuel economy, msc thesis, clemson university, 2007. 7. paul t. williams, high value products from scrap , department fuel and energy , the university of leads retrived from reporter leads . ac. uk /443/tyres.htm , reporter 443, 22 november 1999 . 8. www.wast online.org.uk, end of life vehicle and tyre recycling – information sheet , refrived from www.wast online.org. uk , 2007 . لإلطار النموذجية المكونات 1 رقم الجدول    اإلطار مكونات  المادة على تحتوي التي األجزاء عدد   %الوزن  الهيدروكاربوني المطاط 100 51  الكاربون أسود 50 26  زيوت 25 13  كبريت 2 1  الزنك أوكسيد 4 2   *أخرى كيميائية تمركبا 15 7 )للتفاعل مساعدة وعوامل ، الفلكنة ومعجالت منشطات ، حشوات ، عضوية غير مواد (األخرى الكيميائية المركبات تتضمن* (www.wastonline.org.uk)        2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   63 أإلطارات تدوير خالل من مطاطي قارن تصميم   (parkash,2007)اإلطار وطبقات مكونات يوضح 1 رقم الشكل  والمطاط االلياف من تتكون المركبة المادة من طبقة 2 رقم شكل               2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  64 سلمان هادي حسنو حسين علي سينتح. د   (gitin,1995)إطاري قارن في مقطع 3 رقم الشكل     القوارن من نوعين 4 رقم الشكل   2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   65 أإلطارات تدوير خالل من مطاطي قارن تصميم          (baker,2003) المستعملة اإلطارات لشرائح اإلجهاد مقابل االبتدائية العمودية االنفعاالت 6 رقم الشكل 2012 لسنة 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  66 سلمان هادي حسنو حسين علي سينتح. د      التحميل وإزالة التحميل دورة خالل المستعملة اإلطارات لشرائح النموذجي السلوك 7 رقم الشكل (humphrey, 1993)     2012 لسنة shear stress,psi القص اختبار أساس على محسوبة المستعملة تاإلطارا لشرائح القص إجهاد 8 رقم الشكل  (baker,2003)المباشر 67-52 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   67 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 562 free vibration analysis of squared simply supported plates containing various crack configurations nathera abdual hassan saleh basrah university, engineering college , mechanical department e-mail : nathera1971@yahoo.com abstract this work investigates a free vibration analysis of plates containing a single crack as the crack parameters (i.e. length , orientation and location) is varied. the influences of these parameters on the natural frequencies and the corresponding mode shapes are examined for several squared simply supported plates including internal crack or edge crack or corner crack. vibration analysis for these plates is carried out using finite element method through ansys package version 11 . the validation results are presented and compared with the most recent numerical results found in literature. it is found from present study that the length of the crack as well as its orientation and location are shown to have significant effects on the natural frequency and mode shape of the plates. some new cases are also discussed in detail. the study is particularly useful in the understanding and offering a better insight into the free vibration of the plates with various crack configurations. keywrds: free vibration, cracked plate, finite element method (ansys) تحتوي أشكال شق مختلفة مربعة اسناد بسيط صفائحتحليل االهتزاز الحر ل نظيره عبدالحسن صالح قسم الهندسة الميكانيكية –كلية الهندسة –جامعة البصرة الموجز صفائح تحتوي على شق مفرد عند تغير محددات الشق )الطول , الموقع و هذا العمل يبحث االهتزاز الحر ل مربعة صفائحلتأثير هذه المحددات على الترددات الطبيعية و أشكال النمط المرادفة لها ةتم دراسالميالن(. متعددة تحتوي على شق داخلي , شق جانبي أو شق زاوية. تحليل االهتزاز لهذه الصفائح مسندة اسناد بسيط ائج المصدقة و قورنت النت قدمت نفذت بأستخدام طريقة العناصر المحددة من خالل الحقيبة البرمجية االنسس. وجد من الدراسة الحالية بأن طول الشق و كذلك ميالنه و موقعه لهم و قدمع أحدث النتائج العددية المتوفرة. تأثيرات واضحة على التردد الطبيعي و شكل النمط للصفائح. بعض الحاالت الجديدة ايضًا نوقشت بتفصيل. أن أشكال شق مختلفة. على تحتوي التي ى االهتزاز الحر للصفائحالدراسة مفيدة جدًا في فهم و عرض أفضل إل 1. introduction engineering structures may have structural defects such as cracks during manufacturing or due to service loadings. the presence of a crack in a structural member causes a local flexibility affecting nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 566 its static and dynamic characteristics such as static deflections, natural frequencies and mode shapes. much research work had been done by investigators to study the effects of cracks on the dynamic characteristics of structural elements such as shafts, beams and plates. a comprehensive review on the literature through the period (1971-1992) of the vibration of cracked structures was made by (dimarogonas,1996). in this literature, different modeling techniques of structures with cracks are presented and summarized into three categories, namely: equivalent reduced section, local flexibility from fracture mechanics, and cracked continuous bar or beam. therefore, the reader can be referred to this review paper on the vibrations of cracked plates studied in that period. since then, research and publication on this subject has been at an increasing rate. it is well known that exact analytical solutions exist for plates without crack. so numerical solutions or experimental methods can be constructed to consider the vibrations of cracked plates with various crack configurations and arbitrary boundary conditions. both rayleigh-ritz or ritz method and the finite element method have been often used. many published research is available about the vibrations of cracked plates based on the rayleighritz method. (lee and lim,1993) studied the vibration of center cracked rectangular plates with simply support conditions taking into account shear deformation and rotary inertia. (liew et al.,1994) employed the decomposition method to determine the natural frequencies of a plate having an edge or central crack. they assumed the cracked plate domain to be an assemblage of small sub domains with the appropriate functions formed and led to a governing eigenvalue equation. (ramamurti and neogy, 1998) have applied the generalized rayleigh-ritz method to determine the natural frequency of cracked cantilevered plates. (khadem and razaee, 2000 ) introduced a modified comparisons functions to analyze a simply supported rectangular plate with a crack having an arbitrary length, depth and location parallel to one side of the plate. those functions are derived using the rayleigh–ritz method. the elastic behavior of the plate at crack location is considered as a line spring with a varying stiffness along the crack. recently, (huang et al., 2008, 2009, 2011) proposed a set of regular polynomial admissible functions based on ritz method to describe the stress singularity behaviors around a crack tip. they employed the proposed approach on simply supported and cantilevered plates with single v-notch (huang et al., 2008) , side crack (huang et al., 2009) as well as central crack and side crack (huang et al., 2011). the finite element method is applied to analyze vibration problems of cracked plates . (krawczuk , 1993) and (krawczuk and ostachowicz, 1994) calculated the flexibility matrix of a plate with the crack as a sum of the non cracked plate and an additional flexibility matrix caused by the crack. (yang and chen, 1996) developed an assumed hybrid-stress finite clement model incorporating with two types of multilayer hybrid-stress elements (mltup and mltph) to study the free vibration of patched cracked laminates. the mltup element is used to model the region of an unpatched cracked panel, while the mltph element is used to model the region of a cracked panel adhesive patch. (ma et al., a-b 2001) used the commercial finite element abaqus package and selected eight-node two-dimensional shell elements to determine natural frequencies of cantilevered thin plates with horizontal or vertical side cracks to verify the correctness of their experimental results. they utilized an optical method based on the amplitude fluctuation electronic speckle pattern interferometry in their experimental work. recently, (bachene et al., 2009) applied the extended finite element method to analyze the free vibrations of plates containing central or edge cracks with different boundary conditions. further, the finite element results have been used in the area of non-destructive damage evaluation for damage identification in plates (cornwell et al., 1999, anne et al., 2002, chang and chen, 2004, bijaya and wei-xin, 2006 and sandesh and shankar, 2009). these methods are based on the fact that local damages usually cause decrease in the plate stiffness, which produces the change in vibration characteristics (such as natural frequencies, mode shapes and curvature mode shapes) of the structure. damage is determined through the comparison between the undamaged and the free vibration analysis of squared simply supported plates containing various crack configurations 562 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 damaged state of the structure. the most common dynamic parameters used in damage detection are natural frequencies and mode shapes. in summary, to the author's best knowledge, the major concern in the previous studies has been carried out on plates with very specific cracks (i.e. central crack or edge crack) with varying crack length or crack orientation. few studies have been performed to evaluate the influence of crack location on the natural frequency for edge cracked plates (huang et al., 2009, 2011)and internally cracked plate (khadem and razaee, 2000). so, the purpose of the present paper is to investigate the effects of crack parameters (i.e. length , location and orientation) on the natural frequency of the plates. in this regard, a set of eigenvalues vibration analysis is conducted for a various cracked plates including edge crack or internal crack or corner crack . the computations are carried out using ansys software version 11, a commercial finite element package. 2theoretical analysis the dynamics of plates, which are continuous elastic systems, can be modeled mathematically by partial differential equations based on newton’s laws or by integral equations based on the considerations of virtual work. it is well known that the natural vibrations of plates are functions of the material properties and the plate geometry only, and are inherent properties of the elastic plate, independent of any load. thus, the equation of motion for the transverse vibration of a plate as (chakraverty, 2009):     ,, w ,,w 2 2 4 otyx t htyxd      (1) where w(x,y,t) is the transverse displacement of the plate and t is the time.  2 3 112   eh d is the plate's flexural rigidity. e , ν and ρ are the young's modulus , poisson's ratio and density of the plate material respectively and h is the plate thickness. 4 4 22 4 4 4 4 ww 2 w w yyxx          is the bi-harmonic operator. deflection w must satisfy the boundary conditions at the plate side (these conditions practically do not differ from those in the case of static equilibrium) and the following initial conditions: when    yx t yxt oo ,v w , ,w w: 0     where wo and vo are the initial deflection and initial velocity respectively for point (x,y). equation (1) is the governing, fourth-order homogeneous partial differential equation of the undamped, free, linear vibrations of plates. a complete solution of the problem of a freely vibrating plate is reduced to determining the deflections at any point for any moment of time. however, the most important part of the problem of free flexural vibrations of plates is to determine the natural frequencies and the mode shapes of the vibration (deflection surfaces in two dimensions) associated with each natural frequency. for such a problem, equation (1) is an eigenvalue problem. the natural frequencies are the eigenvalues and associated shape functions are the eigenfunctions. a solution of equation (1) can be obtained by applying the classical analytical and approximate methods discussed in reference [20]. in the case of a simply supported square plate (figure 1) , the natural frequency may be expressed as : nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 562 2n h d a k    (2) where ωn : is the natural frequency k : is the frequency parameter a : is the plate side for example, table (1) gives the first five frequency parameters for a simply supported square plate chakraverty,2009. in the cases of cracked plates firstly the eigenvalue vibration analysis is performed then the relevant values of frequency parameter for cracked plate (kcracked) are determined in each case. for such cases, the following equation can be considered in order to determine the frequency parameter: 2 n d h ak cracked   (3) 3. finite element modeling of cracked plates 3.1 model description there are many crack parameters involved in modeling and analyzing of the problem under study. these parameters include crack length, location and orientation. due to such a variety of contributing parameters, three different models are established for analysis purpose. the models cover internally, edge and corner-cracked plates as shown in figure 2. the crack was presumed to be through thickness since thin plate is used and having no friction between their edges and no propagation was allowed. the considered cracked plates have all their sides simply supported. it are characterized by the following dimensionless geometric parameters: plate's aspect ratio equal to (1), relative plate's thickness (h/a = 1/100), relative crack's length (c/a = 0.1 0.5) and orientation (θ = 0 o 90 o ) as well as relative crack location (x/a = 0.1, 0.3 , 0.4 , 0.5 ), as indicated in table 2. the plate material considered is supposed to be linear elastic and isotropic with young's modulus : e=200gn/m 2 , possion's ratio : ν = 0.3 and density , ρ = 7860 kg/m 3 . the commercial finite element package ansys version11 is utilized for the modeling and vibration analysis of cracked plates. the "shell93" element of ansys element library was used for meshing procedure. this element is suitable for analysis thin-walled structures. it is a eight-node element with six degree of freedom at each node: translations in the nodal x, y, and z directions and rotations about the x, y, and z-axes. the element has plasticity, stress stiffening, large deflection, and large strain capabilities. the adopted finite element mesh is displayed in figure 3 where the element’s refinement around the crack’s tips has been carefully considered for an accurate evaluation. the "block lanczos" mode extraction method was used to calculate the natural frequency of the cracked plates then the frequency parameters can be computed from equation (3). 3.2 model verification in order to illustrate the accuracy and applicability of the proposed finite element model, two case studies have been selected. simply supported edge and central cracked square plates with different relative crack length (a/b=0.1 – 0.5) for crack orientation (θ=0 o , 90 o ) which are reported by (huang et al., 2009) and (bachene et al., 2009) respectively, as shown in figure 4. thus, the quality of the final pattern and density of the finite element mesh have been accepted after several convergence tests in which the mesh density and element shapes have been varied with that case studies. figure 4 indicates the effect of the crack relative lengths on the first five frequency parameters (k). it is clearly observed there is a very good convergence between the results of the present study and those obtained in reference (huang et al., 2009) and (bachene et al., 2009). free vibration analysis of squared simply supported plates containing various crack configurations 562 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 4results and discussions it is interesting to observe how the frequency parameters change with crack length, orientation and location. consequently, figures 5 and 6 indicate the values of the first five frequency parameter (k) versus crack orientation (θ) for different relative crack length (c/a) and crack location (x/a) of internally cracked plate and edge cracked plate respectively. also, variations in values of the first five frequency parameter of a plate with corner crack versus relative crack length and crack orientation have been plotted in figure 7. further, the reduction in frequency parameters due to cracks at different lengths, orientations and locations were computed by the following equation: % % re uncracked crackeduncracked k kk duction   (4) in general, at the initial investigation of these figures, it is clearly observed that when the length of the crack increases the value of the frequency parameter decreases for all the five modes and for the three types of cracked plates. although the amount of frequency parameter drop is dependent on the case (i.e. cracked plate) and mode of interest. this phenomenon can be expected as a result of the associated stiffness reduction (huang et al., 2009) and (bachene et al., 2009). besides, it is seen that small crack (i.e. c/a=0.1) produce a low influence on frequency parameters in various orientations and locations as compared with intact plate, e.g. which are highest reduced only by about 1.564% at (θ=0 o and x/a=0.5), 0.217% at (θ=45 o and x/a=0.3) and 0.255% at (θ=45 o ) for internally, edge and corner cracked plates respectively in fifth mode. because of the different behavior of the three consideration cases in various lengths, orientations and locations, each case are discussed separately. 4.1 internally cracked plate in figure 5, the frequency parameters of the first mode are slightly sensitive to the crack orientation than the other modes, thus the variation in highest drop occurs between 10.44% and 11.4% at x/a=0.5. while, in second mode the change in frequency parameters with crack orientation would have very little as the crack moves towards the middle of the plate, with maximum reductions of (15.56-10.79)% , (13.75-12.57)% and (13.26-12.88)% for crack locations at x/a=0.3 , x/a=0.4 and x/a=0.5 respectively. also, it is noticed that the presence of the crack of any length in different orientations and locations has less influence on the frequency parameters of the third mode with respect to other modes. thus, the maximum drop occurs at the crack location x/a=0.3 of crack length c/a=0.5 and crack orientation θ=45 o by about 3.54%. moreover, from the observation of this figure, it can be deduced that the behavior in fourth mode is opposite to the behavior in fifth mode, especially for crack length c/a=0.4 and 0.5 at x/a=0.3 and 0.5. changing the crack orientation from θ=0 o to 45 o and as the crack approaches to the plate centre, firstly the frequency parameters reduces then increases at crack location x/a=0.3, while it is always decreased at x/a=0.4 and 0.5 in fourth mode. but, in fifth mode the frequency parameters firstly increases then reduces at x/a=0.4. an interesting phenomenon is presented in figure 5. the largest drop of the frequency parameters is noticed when crack orientation θ=45 o of the first and third modes by about 11.4% at x/a=0.5, 3.54% at x/a=0.3 respectively, while in forth mode it is observed when crack orientation θ=15 o by about 12.62% at x/a=0.3. further, the highest reduction in frequency parameters always occurs when crack orientation θ=0 o in second and fifth modes, by about 15.56% and 22.49% respectively at x/a=0.3. 4.2 edge cracked plate figure 6 shows that in first mode, the frequency parameters are firstly decreased then increased depending on crack orientation, although the opposite happens for crack location x/a=0.5 with nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 522 maximum reductions of 7.32% at (θ=45 o and x/a=0.1), 6.027% at (θ=75 o and x/a=0.3) and 5.73% at (θ=90 o and x/a=0.5). in second mode, decreasing or increasing in the frequency parameters significantly influence by crack orientation and crack location especially for relative crack length c/a=0.4 and 0.5, thus the largest drop occurs at (θ=90 o and x/a=0.1) by about 12.44%. it can be seen that in third mode when the crack is located at x/a=0.3, the frequency parameters are more affected than other locations with maximum reduction of 5.056% at θ=45 o . further, in fourth mode the frequency parameters extensively decreases as the crack approaches the plate centre by about 18.37% at (θ=90 o and x/a=0.5) and it is less affected by crack orientation at x/a=0.1. interestingly, the frequency parameters of the fifth mode are slightly sensitive to the crack orientation for relative crack length c/a = 0.10.4, while the influence of crack orientation is very clear for relative crack length c/a=0.5 at crack location x/a=0.1 and 0.5 with greatest reduction of 22.97% and 18.32% respectively at θ=45 o . although, when the crack is located at x/a=0.3, the crack orientation are shown to have significant effects on the frequency parameters with maximum drop of 20.93% at θ=90 o . an important finding have been revealed in figure 6 that for the cracks at the location x/a=0.3 an intermediate behavior is observed. 4.3 corner cracked plate it is obvious from figure 7 that the increasing of crack orientation from θ=15 o 45 o generally reduces the frequency parameters of the first, second and forth mode by about 9.94% at c/a=0.5, more than 9.24% at (0.1<c/a<0.5) and more than 7.84% at (0.1<c/a<0.4) respectively. while, for relative crack length c/a=0.5 in the second and fourth modes the highest drop occurs at θ=15 o by about 15.47% and 14.34% respectively. in third mode, the frequency parameters are almost unchanged with relative crack length and crack orientation, however there is a very little reduction occurs at c/a=0.5 and θ=15 o by about 1.08% . further, it can be observed for fifth mode that the effect of the crack orientation starts to appear significantly at c/a>0.3. accordingly, with growing crack orientation the frequency parameters firstly increase then decrease by about 18.82% at θ=45 o . the above mentioned findings of the reduction in frequency parameters (i.e. decreasing or increasing) for three cases can be explained by deformed mode shapes. so, figures 8 and 11 show the first five vibration mode shapes for uncracked plate as well as only for cracked plates characterized by c/a=0.5 , x/a=0.3,0.4,0.5 and θ=0 o ,45 o of internally cracked plate, c/a=0.5 , x/a=0.1,0.3,0.5 and θ=45 o , 90 o of edge cracked plate and c/a=0.5, θ=15 o ,45 o of corner cracked plate respectively. since similar results (i.e. similar behavior) were obtained for cracked plates having another crack parameters for brevity. it is seen from figures 9 and 11 that how the cracks opens and splits the plate depending upon the mode of interest as well as crack parameters with respect to the separator region between convexity surface and concavity surface of the mode shape. the splitting phenomenon of the plate explains the loss in rigidity of the plate, inducing a drop in the mode frequencies, (bachene et al., 2009). furthermore, it is evident that the deformed mode shapes in first mode have one region either convexity or concavity. while in second and third modes it have two regions one convexity and the other concavity. also, in fourth and fifth modes that the deformed mode shapes changes its shape and have more than two regions. consequently, one region is under tension and the other is under compression. this may be the reason for varying the reduction in frequency parameters by depending upon these region with respect to crack parameters and supported edges. 5. conclusions in the present paper, the free vibration analysis of variously cracked square thin plates has been considered. finite element method has been preformed through ansys package in order to determine the frequency parameter. in particular, the effects of the crack length, crack orientation and crack location on the natural frequencies and the corresponding mode shapes have been investigated. on the basis of the achieved results the following conclusions can be stated : free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 1the numerical simulations show that if the crack length increases, a frequency reduction takes place. 2the change in frequencies due to the presence of a crack is a function of the crack parameters and it also depends upon the mode shapes of the plate. 3it is shown from the computed results that the crack orientation has less effect on frequencies for the internal crack plate than the edge crack and corner crack in the first mode. 4the frequencies of the third modes are less sensitive to the crack parameters than the other modes for the three cases of cracked plates. 5by depending on the fundamental mode (i.e. first mode), internally cracked plate with crack orientation (θ=45 o ) can be considered to be the most dangerous one. since it has the highest reduction in frequency parameter. 6. references (anne teughels , johan maeck and guido de roeck., 2002) "damage assessment by fe model updating using damage functions". computers and structures;80; 1869–1879. (bachene m., tiberkak r. and rechak s., 2009) "vibration analysis of cracked plates using the extended finite element method". archive of applied mechanics;79;249–262. (bijaya jaishi and wei-xin ren, 2006) "damage detection by finite element model updating using modal flexibility residual", journal of sound and vibration;290;369–387. (chakraverty s., 2009) "vibration of plates". taylor & francis group. (chang c-c and chen l-w., 2004) "damage detection of a rectangular plate by spatial wavelet based approach". applied acoustics;65;819–32. (cornwell, p., doebling, s.w. and farrar, c.r., 1999) "application of the strain energy damage detection method to plate-like structures". journal of sound and vibration;224 (2);359–374. (dimarogonas a.d., 1996) "vibration of cracked structures: a state of the art review". engineering fracture mechanics;55 (5); 831–857. 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(ramamurti v. and neogy s., 1998) "effect of crack on the natural frequency of cantilever plates a rayleigh–ritz solution". mech struct mach; 26(2);131–43. (sandesh s. and shankar k., 2009) "damage identification of a thin plate in the time domain with substructuring-an application of inverse problem", international journal of applied science and engineering;7(1);79-93. (shau-hwa yang and wen-hwa chen., 1996) "free vibration analysis of patched cracked composite laminates using a multilayer hybrid-stress finite element method". engineering fracture mechanics;54(4);557-568. table 1 values of first five frequency parameters of a simply supported square plate mode no. frequency parameters first 19.739 second 49.348 third 49.349 fourth 79.4 fifth 100.17 table 2 the values of crack parameters in the finite element model. case study c/a θ x/a internal crack 0.1, 0.2, 0.3, 0.4, 0.5 0, 15, 30, 45 0.3,0.4, 0.5 edge crack 0.1, 0.2, 0.3, 0.4, 0.5 15, 30, 45, 60, 75, 90 0.1, 0.3, 0.5 corner crack 0.1, 0.2, 0.3, 0.4, 0.5 15, 30, 45 corner figure 1 geometry of simply supported square plate. free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 figure 2 cracked square plate with crack type details. figure 3 samples of the finite element model for different type of cracked plate with crack-tip mesh refinement detail. nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 522 figure 4 verification case studies. free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 526 free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 figure 7 variation of first five frequency parameters to the relative crack length for different crack orientation in corner cracked plate. figure 8 first five deformed mode shapes for simply supported uncracked plate. nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 522 figure 9 first five deformed mode shapes for simply supported internally cracked plate with relative crack length c/a=0.5 free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 figure 10 first five deformed mode shapes for simply supported edge cracked plate with relative crack length c/a=0.5. figure 11 first five deformed mode shapes for simply supported corner cracked plate with relative crack length c/a=0.5. influence of degree of crushing of coarse aggregate on properties of asphalt paving mixtures used for surface courses al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٦ influence of degree of crushing of coarse aggregate on properties of asphalt paving mixtures used for surface courses assistant lecturer. abbas talib al-hudabi civil eng. depa., engineering college – kufa university. abstract there are several properties of coarse aggregate used in hot mix hot laid asphalt concrete mixtures such as surface texture, percentage of crushing, polished stone value, coating and stripping and percentage of wear that are influence the behavior of asphalt paving mixtures. the effect of percentage of crushing of coarse aggregate used in asphalt concrete mixtures prepared to surface courses according to the standard specification for roads and bridges in iraq has been studied. four percentages of crushing of coarse aggregate (0%, 40%, 70% and 100%) selected to indicate the influence of percentage of crushing on asphalt concrete mixture properties (bulk specific gravity, % air voids, % voids in mineral aggregate, marshall stability, marshall flow, indirect tensile strength, index of retained strength). according to this study, the mixtures with 40% fractured coarse aggregate accommodate the requirements of iraqi specification of roads and bridges (scrb). key words: asphalt concrete, % of crushing, coarse aggregate, marshal stability, standard specification. المستخدمة للطبقات اإلسفلتیةخواص الخلطات نسبة التكسیر للحصى الخشن على تأثیر السطحیة الھدابيعباس طالب محسن. مدرس مساعد جامعة الكوفة–كلیة الھندسة –قسم الھندسة المدنیة الملخص حرارة العالیة والمفروشة الممزوجة بدرجات الاإلسفلتیةتوجد خواص كثیرة للحصى الخشن المستعمل في الخلطات وكل ھذه الخواص تؤثر التآكلونسبة ، التقشر، قیمة صقل الحجر، نسبة التكسیر، بدرجات حرارة عالیة مثل نوعیة سطح الحبیبات اإلسفلتیةنسبة التكسیر للحصى المستخدم للخلطات تأثیرفي ھذه الدراسة تم دراسة .اإلسفلتیةلخلطات التبلیط األداءعلى سلوك نسب مختلفة لدرجة تكسیر أربعتم اختیار .المحضرة للطبقات السطحیة حسب المواصفات القیاسیة للطرق والجسور العراقیة الوزن النوعي (اإلسفلتیةلخلطات لالفیزیائیةخواصالنسبة التكسیر على تأثیرلتحدید %) ١٠٠و % ٧٠، %٤٠، %٠( الحصى قاومة الشد الغیر مباشر ونسبة المقاومة مو، جریان مارشال، ثبات مارشال، فراغات بالركامنسبة ال، نسبة الفجوات الھوائیة، للخلطة تستوفي % ٤٠التي تحتوي على ركام خشن بنسبة تكسیر تساوياإلسفلتیةالخلطات وبحسب ھذه الدراسة وجد بان ).المسترجعة .السطحیةللطبقة )scrb(متطلبات المواصفات القیاسیة العراقیة للطرق والجسور al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٧ nomenclature: aashto: american association of state highway and transportation officials astm: american state of testing and materials irs: index of retained strength its: indirect tensile strength scrb: state corporation for roads and bridges shrp: strategic highway research program sorb: state organization of roads and bridges in iraq superpave: superior performing asphalt pavements vma: voids in mineral aggregate introduction asphaltic mixtures are a uniformly mixed combination of asphalt cement, coarse aggregate, fine aggregate and other materials, depending on the type of asphalt mixture. the different, types of asphaltic concretes commonly used in pavement conduction are hot-mix, hot-laid and cold-mix, cold-laid. asphaltic concrete is the most popular paving material used in iraq. when used in the construction of highway pavements, it must resist deformation from imposed traffic loads, be skid resistant even when wear and not be easily affected by weathering forces. the degree to which an asphaltic concrete achieves these characteristics is mainly dependent on the design of the mix used in producing the concrete (garber 2009). hot-mix hot-laid asphaltic concrete: hot-mix, hot-laid asphaltic concrete is produced by properly blending asphalt cement, coarse aggregate, fine aggregate, and filler (dust) at temperatures ranging from about 175 f to 325 f, depending on the type of asphalt cement used. suitable types of asphaltic materials include ac-20, ac-10, and ar-8000 with penetration grades of 60-70, 85-100, 120-150, and 200-300. hot-mix, hot-laid asphaltic concrete is normally used for high-type pavement construction, and the mixture can be described as open-graded, coarse-graded, dense-graded, or fine-graded. when produced for high-type surfacing, maximum sizes of aggregates normally range from 3/8 in. to 3/4 in. for opengraded mixtures, 1/2 in. to 3/4 in. for coarse-graded mixtures, 1/2 in. to 1 in. for dense-graded mixtures, and 1/2 in. to 3/4 in. for fine-graded mixtures. when used as base, maximum sizes of aggregates are usually 3/4 in. to 1 1/2 in. for openand coarse-graded 1 in. to 1 1/2 in for dense grades and 3/4 in. for fine-graded mixtures. as stated earlier, the extent to which an asphalt concrete meets the desired characteristics for highway pavement construction is dependent mainly on the mix design which involves the selection and preparing of the different material components. however, note that when designing hot mix asphalts concrete, a favorable balance must be found between a highly stable product and a durable one therefore the overall objective of the mix design is to determine an optimum blend of the different components that will satisfy the requirements of the given specifications (garber 2009). aggregate gradation aggregate are usually categorized as crushed rock, sand, and filler. the rock material is predominantly coarse aggregate retained in a no.8 sieve, sand is predominantly fine aggregate passing the no.8 sieve, and filled is predominantly mineral dust that passes the no. 200 sieve. it is customary for gradations of the combined aggregate and the individual fractions to be specified. the first phase in any mix deign is the selection and combination of aggregates to obtain a gradation within the limits prescribed. this is sometimes referred to mechanical stabilization. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٨ consensus aggregate properties the pavement experts agreed that certain aggregate characteristics are critical to well performing asphalt mixtures. these characteristics are called "consensus properties" because there was wide agreement in their use and specified values. those properties are coarse and fine aggregate angularity, flat and elongated particles, and bulk and apparent specific gravity (sp-2, 2000). the aggregate was washed to ensure that all materials are clean, free from injurious amounts of clay balls and clay coated particles, organic matter and other deleterious substances. coarse and fine aggregate angularity coarse and fine aggregate angularity property ensure a high degree of aggregate internal friction and rutting resistance. the coarse aggregate angularity is determined by degree of crushing which is defined as the percent by weight of aggregate larger than 4.75 mm with one or more fractured face according to scrb requirements (scrb (2003)). the degree of crushing (testing according to astm d5821) shall be such that at least 90% by weight of the materials retained on the no. 4 (4.75 mm) sieve has one or more fractured faces (scrb (2003),and in the other hand aashto requirements for the conventional mixtures (dense or open graded) shall be at least 40% (aashto 2004). the fine aggregate angularity is defined as the percent air voids present in loosely compacted aggregates smaller than 2.36 mm "test method for uncompacted void content of fine aggregate (as influenced by particle shape, surface texture, and grading)" under designation (aashto tp33) (asphalt institute (2000)). asphalt institute manual (asphalt institute (2000) is devoted to superpave mixture design and analysis. superpave is short for superior performing asphalt pavements. higher void contents mean more fractured faces (sp-2, 2000). asphalt content having determined a suitable mix of aggregates, the next step is to determine the optimum percentage of asphalt that should be used in the asphalt concrete mixture. this percentage should, of course, be within the prescribed limits. the gradation of the aggregate determined earlier and the optimum amount of asphalt cement determined combine to give the proportions of the different materials to be used in producing the hot mix hot–laid concrete for the project under consideration. these determined proportions are usually referred to as the jobmix formula. two commonly used methods to determine the optimum asphalt content are the marshall method and the hveem method (garber 2009). scope of the study the main purpose of this study is to evaluate the effect of percentage of crushing of coarse aggregate used in asphalt concrete mixtures that is recommended for surface courses. four percentage of crushing are used in this study that are (0%, 40%, 70% and 100%) to indicate these effect on the properties of asphalt concrete mixtures and to compare the results with the scrb specifications and aashto requirements . materials and testing program materials the materials (asphalt cement, aggregate and filler) used in this study are widely available and currently used in road paving in iraq. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٥٩ asphalt cement one type of asphalt cement (40-50 penetration grade) produced from alshuaba refinery is used in this work, physical properties and other necessary tests for this asphalt cement are presented in table (1). aggregates (coarse and fine materials): a coarse aggregate used in this work is brought from the hot mix plant at alnajaf city, the source of aggregate is from nibaee quarry. the combined gradation of aggregates and filler is shown in table (2) according to specification for roads and bridges (scrb r/9 (2003)) for surface course with maximum size of 12.5 mm. the chemical composition and physical properties of the aggregate are indicated in tables (3) and (4) respectively. mineral filler: one type of filler is used in this work which limestone dust collected from materials was passing sieve no. 200. the physical properties of the limestone dust are shown in table (5). test methods three methods for testing which are used in this study to evaluate the influence of degree of crushing of coarse aggregate on properties of asphalt concrete mixture, these are: marshall test method, (d1559). indirect tensile strength (i. t.s.), (d4123) index of retained strength (i. r. s.), (d1075). mixture preparation: the aggregates are dried to constant weight at 110 c, and then separated into the desired sizes to meet the required gradation for the mixtures, as shown in table (2). after heated aggregate and asphalt cement to the temperature which produced a kinematic viscosity of (170± 20) centistokes (up to 163 c as an upper limit), then we add the amount of asphalt cement to the heated aggregate, and mixed thoroughly until all aggregate particles are coated with asphalt. a constant mixing temperature is followed in this work with about 150 c. resistance to plastic flow of asphalt concrete mixtures (marshall method (d1559)): procedure of preparation and testing specimens according to this method is described in astm d 1559. this method covers the measure of the resistance to plastic flow of cylindrical specimens (2.5 in. height × 4.0 in. diameter) of asphalt paving mix loaded on the lateral surface of specimen by means of marshall apparatus with a constant rate of 50.8 mm/min (2 in./min) until the maximum load is reached. the maximum load resistance and the corresponding strain values are recorded as marshall stability and flow respectively, at test temperature of 60 c. three specimens for each combination were prepared and average results are reported. the bulk specific gravity and density (astm d2726), and percent air voids (astm d3203) are determined for each specimen. the test specimens are compacted using 75 blows/end according to the scrb. indirect tensile strength (d4123): the method of mixing and the dimensions of the specimens, as well as, the number of blows by compaction hammer remained as those described for marshall test. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٠ astm d4123 method which determined the indirect tensile strength of asphalt concrete mixture has been used for this purpose. the specimens brought to the specified test temperature (25 c) by immersing them in water bath at the temperature for 30-40 minutes, then tested for indirect tensile strength at a rate of 50.8 mm/min using a 1/2 in. wide, curved, stainless steel loading strip on both the top and bottom, running parallel to the axis of the cylindrical specimens, until reaching the ultimate load resistance. indirect tensile strength (its) is calculated from the following equation astm d 4123 (astm, 1995): …… (1) where: its=indirect tensile strength (kg/cm2), pult= ultimate applied load (kg), t= thickness of the specimen (cm), and d=diameter of the specimen (cm). index of retained strength (d1075): index of retained strength test is used to evaluate moisture damage of asphalt pavement. this test is also called "effect of water on cohesion of compacted bituminous mixtures" as in astm d1075 (astm 1995). it is one of tests required by scrb specifications to be performed on asphalt mixes used in surface course in addition to marshall test. this test is intended to measure the loss of cohesion resulting from the action of water on compacted bituminous mixtures penetration grade asphalt. the method of mixing and the dimensions of the specimens, as well as, the number of blows by compaction hammer remained as those described for marshall test. astm d1075 (astm 1995) described the method for determine the index of retained strength; in this study we take marshall test procedure to determine i.r.s %. the numerical index of resistance of bituminous mixtures to the detrimental effect of water was expressed as the percentage of the original strength that was retained after the immersion period. it is calculated as follows: ….. (2) where: i.r.s.= index of retained strength (%) s1= marshall stability of specimens immersed in water bath for (30-40 minutes) at 60 ◦c before testing, kn s2= marshall stability of specimens immersion for 24 hours at 60 ◦c before testing, kn test program of this study: in this study we have been considered the effect of degree of crushing for coarse aggregate on asphalt concrete mixture properties recommended to use as surface course according to scrb r/9. table (6) gives the detailed information about the different mixture combination and tests performed in the experimental plan adopted in this work. results and discussion to evaluate the influence of degree of crushing of coarse aggregate used in surface course, different tests were conducted on mixture properties. that is including bulk density, air voids, voids in mineral aggregate, marshall stability, marshall flow, marshall stiffness, indirect tensile strength and index of retained strength. the results are shown in table (7). al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦١ marshall test results: marshall method followed in this study as resistance to plastic flow. marshall test specimen prepared and bulk density, percent of air voids, stability, flow and marshall stiffness were founded for each prepared specimen, using astm methods and specification figure (1) shows the influence of percentage of coarse aggregate crushing on bulk specific gravity, % air voids and voids in mineral aggregate. the results show that, as percent of crushing increases, the bulk density increases (slightly) while air voids and voids in mineral aggregate decreases, that is because of the surface area will increase with increases of % of crushing then the interlock increases and the bulk density increases and the % of air voids and % of mineral filler will decreases. figure (2) shows the influence of percentage of crushing on marshall stability, marshall flow and marshall stiffness (represents the value conducted by divided marshall stability to marshal flow). these curves indicate that marshall stability and stiffness increases while marshall flow decreases with increasing of percentage of crushing of coarse aggregate (that is because of the interlock and bonding increase with increasing of % of crushing of coarse aggregate). indirect tensile strength results: indirect tensile test were performed to examine the influence of percentage of crushing of coarse aggregate on the low temperature cracking of asphalt concrete pavements. the effect of percentage of crushing on i.t.s at 25 c test temperature is shown in figure (3). as shown in figure (3), its increases with increasing of % of crushing of coarse aggregate. index of retained strength: the determination of index of retained strength for several mixes with different percentage of crushing of coarse aggregate depends on marshall test procedure. figure (4) shows the index of retained strength values for different values of percentage of crushing of coarse aggregate, this curve indicate that i.r.s increases with increasing of percentage of crushing. conclusions within the limitations of materials and test program used in this work, the following are concluded: aas percentage of crushing of coarse aggregate increases: 1. bulk density of asphaltic concrete increases slightly, 2. percentage of air voids decreases, 3. percentage of vma decreases, 4. marshall stability increases, 5. marshall flow decreases, 6. marshall stiffness increases 7. index of retained strength increases. 8. indirect tensile strength increases. bthe mixtures with 40% fractured coarse aggregate accommodate the requirements of iraqi specification of roads and bridges (scrb 2003). recommendations  the main recommendation is to study the relationship between the degree of crushing of coarse aggregate accommodate shrp specification on the properties of asphalt concrete mixtures. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٢  the second recommendation is to study the influence of surface area of aggregate on performance of asphalt concrete mixtures. references: aashto (2004), "standard specification for transportation materials and methods of sampling and testing", american association of state highway and transportation officials, part i, part ii, washington, d. c., usa. aashto (1993), "aashto guide for design of pavement structure 1993", american association of state highway and transportation officials, vol. 1 washington, d. c., usa. asphalt institute, 2000, "superpave mix design manual", superpave series no. 2 (sp-2). astm standards, 1995, "roads and paving materials", annual book of the american society for testing and materials standards, section 4, vol. 04-03. hamed m. h. , abbas t. alhdabi , 2001, "influence of carbon black reinforcement on performance of paving materials", a scientific refereed journal published by: college of engineering, university of baghdad, volume 7, number 1, march 2001. mohammed a. h. , 2007, "influence of aging on performance of asphalt paving materials", ph. d. dissertation, university of baghdad, baghdad, iraq. nicholas j. garber and lester a. hoel, 2009,"traffic and highway engineering", fourth edition. state corporation for roads and bridges (scrb), 2003"general specification for roads and bridges", republic of iraq, ministry of housing and construction, department of planning and studies, baghdad, revised edition, addendum no.3. von quintus, h. sherocman, j. kennedy, and hughes c. s., 1988, "asphalt aggregate mixture analysis system", final report to the national corporative highway research program, nchrp report 338.national research council, washington, d. c. yoder e. j. and witczak m. w. , 1975, "principle of pavement design", second edition, john wiley and sons, new york. :المصادر باللغة العربیة .١٩٨٥، مود توفیق سالم دكتور مح، ھندسة الطرق ٢٠٠١د بغدا، المركز القومي للمختبرات اإلنشائیة، اإلنشائیةمواصفات المواد al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٣ table (1): the physical properties of asphalt cement type property unit asphalt cement grade (40-50) scrb specifications 1. penetration on (25 c, 100 gm, 5 sec.) 2. ductility (25 c, 5 cm/min) 3. softening point 4. flash point 5. specific gravity at 25 c 1/10 mm cm c c --42 175 52 273 1.04 40-50 >100 -->232 --after thin film oven test retained penetration, % of original ductility of residue loss in weight (163 c, 50 gm, 5 hrs) % cm % 79 105 0.183 >52 >25 --table (2): selected gradation of aggregate, scrb specification requirements and restricted zone suggested by superpave for 12.5 mm normal size sieve (mm) percent passing ofavailable aggregate scrb1 specification requirements restricted zone by superpave2 19 100 100 --12.5 95 90-100 --9.5 83 76-90 --4.75 55 44-74 --2.36 40 28-58 39.1 1.18 ----25.6-31.6 0.60 ----19.1-23.1 0.30 15 5-21 15.5 0.075 8 4-10 --% of asphalt cement 5 4-6 --1. scrb, 2003. 2. asphalt institute (sp-2), 2000. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٤ table (3): chemical composition of nibaee aggregate chemical compound results % l. o. i si o2 ca o mg o so3 fe2 o3 al2 o3 total 6.55 82.52 5.37 0.78 2.7 0.69 0.48 99.09 mineral composition quartz calcite 80.03 10.92 table (4): physical properties of nibaee aggregate property coarse aggregate fine aggregate bulk specific gravity 2.64 2.67 apparent specific gravity 2.695 2.701 percent water absorption 0.483 0.692 table (5): physical properties of mineral filler (limestone dust) property test method result scrb specification passing sieve no. 200, % specific gravity plasticity index --astm c128 aashto t90 100 2.79 1.5 100 --≤ 4 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٥ table (6): experimental plan mix no. % of crushing applied tests marshall test indirect tensile strength index of retained strength 1 2 3 4 5 6 7 8 9 10 11 12 0 0 0 40 40 40 70 70 70 100 100 100 # # # # # # # # # # # # table (7): the main properties results of different mixes mix no. marshall test results at 60 ◦c indirect tensile strength, kpa index of retained strength, % bulk density gm/cm3 air voids, % v.m.a, % stability, kn flow, mm marshall stiffness, kn/mm 1 2.403 3.5 14.56 8.5 3.9 2.179 2 25 3 75 4 2.415 3.0 14.14 9.3 3.5 2.657 5 30 6 78 7 2.430 2.4 13.60 10.4 3 3.467 8 31 9 81 10 2.455 1.4 12.72 10.8 2.7 4.00 11 32 12 83 note: each number represent the average of three spacemen result. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٦ fig. (1) influence of degree of crushing on % of air voids, % vma and bulk density. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٧ fig. (2) influence of degree of crushing on marshall test results al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٦٨ fig. (3) influence of degree of crushing on i.t.s at 25 c fig. (4) influence of degree of crushing on index of retained strength al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 109 effect of capture and escape time constants of enhanced performance for quantum well lasers in direct modulation dr. mohammed adnan mahdi department of laser engineering and opto-electronics university of technology abstract the capture and escape time constants are a small and finite capture and escape time of the carriers between the separate confinement (sch) region and the quantum well. these time constants are in picosecond time scale and are important in the direct modulated quantum well lasers which these small time constants are effected on the gain compression factor where the gain compression factor is effected on the differential gain . the differential gain is one from the important factors for the enhanced performance for the direct modulated quantum well lasers which the output this lasers are depended on it. على تحسین اداء لیزرات البئر الكمي ذات التضمین المباشرتأثیر ثوابت زمن االسر والھروب محمد عدنان مھدي. د قسم ھندسة اللیزر وااللكترونیات البصریة الجامعة التكنولوجیة الخالصة وب ح امالت ال شحنة المح صورة ب ین منطق ة یعرف ثوابت زمن األسر والھروب بأن ھ ال زمن ال صغیر والمح دد ألس ر وھ ر تعتبر ھذه الثوابت الزمنیة مھمة في التضمین المباشر للیزرات .الحصر المنفصل والبئر المكمم وتكون قیم ھذه األزمان بالبیكوسكند ن أح دى العوام ل البئر الكمي حیث تؤثر على عامل الربح المضغوط الذي یؤثر بدوره على الربح التفاضلي حیث یع د ھ ذا ال ربح م . المھمة في تحسین أداء التضمین المباشر للیزرات البئر المكمم كون الخرج اللیزري لھذه اللیرات یعتمد علیھ introduction semiconductor lasers have become one of the most important elements in fiber optic links due to their superior modulation characteristics, size and cost efficiency [agrawal,2002]. the typical laser wavelengths in coherent light communication systems based on semiconductor lasers are 1.3 μm and 1.55 μm, which correspond to the minimum dispersion and attenuation wavelengths, respectively[1,2]. the information is signal can be modulated on semiconductor lasers directly or externally. direct modulation, involves changing the current input around the bias level above al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 110 threshold. it is principally a simpler method and is easier to implement rather than the external modulation, but the output light produced depends on internal dynamics of the laser [pua et al ,1997]. therefore, in order to improve the modulation characteristics such as obtaining higher modulation bandwidth or enhanced modulation efficiency we need to be able to control some of the intrinsic laser parameters such as optical gain or optical confinement factor. there have been many efforts made to improve direct modulation of semiconductor lasers. this challenge actually began with the invention of new materials such as quantum wells (qws), quantum wire(qwrs) and quantum dot (qds) with better carrier and photon confinement that led to higher gain and differential gain and gradually improved by developing better wave guiding and current injections structures[gareso et al ,2006]. theory and analysis a. resonance frequency analysis of semiconductor laser: the analysis of the dynamic behaviour of semiconductor laser starts from the interaction between photon number and carrier number[pua et al .1997]. )1( p gpn ev i dt dn sp ετ + −−= spp np p gp dt dp τ β τε +− + γ = )1( where n is the carrier density, p is the photon density, i is the injection current, γ is optical confinement factor, ε is the gain compression factor ,v is the volume of the optical gain medium, τsp is the carrier recombination lifetime (or spontaneous carrier lifetime) , g is the unclamped material gain, τp is the photon lifetime in the cavity , β represent the fraction of spontaneous emission ,and e is the electronic charge. the photon lifetime, τp, is considered as the average time that the photon remains in the cavity before it gets absorbed or emitted through the facets and is related to the cavity loss as where gν is the group velocity, iα is the internal loss , mα is the mirror losses, and cavα is the cavity loss. at n =nth (nth is the carrier density at threshold ), the gain at threshold (g0 ) is equal the cavity losses( cavα ) ,{ i.e. )()(0 mithngg αα +== }, therefore ,at the steady-state rate equation{(d/dt)=0}, the model gain at threshold [pua et al .1997] is )()(0 mithth nggg αα +γ=γ=γ= (1) (2) cavgmig p ανααν τ =+= )( 1 (3) (4) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 111 but the non-linear gain which it is appeared by the gain compression factor, therefore, 01 p g g ε+ → .by using (3) and (4) , we can the get on a relation ship between the model gain at threshold and photon lifetime and is 01 1 )( p gth p mig ετ ααν + ==+ at the small-signal analysis[2,4], the injection current (the sinusoidal current variations with a time-varying current) consists on the steady-state input dc current (i0) is superimposed with a small ac signal and in a simple case of only one angular frequency ω and constant amplitude im, the injection current is: similar to the injection current, and by using the complex frequency domain notation, the carrier and photon densities can be also expressed as the sum of their steady-state value plus a small ac component: by substituting equations (6) through (8) into the original rate equations (1) and (2) and considering the terms that are first order in ω , the following relationships are obtained: where g′= dg/dn is the differential gain. in the photon density rate equation ,besides substituting equations (6) through (8) into the original rate equations (1) and (2) ,we substitute for the inverse photon lifetime using equation (5) and will have: m th mm pp pg n p pg pj 2 0 0 0 0 / )1(1 ε ε ε ω + + + γ = now from the small-signal solutions to the rate equations we can simply derive the high speed modulation response function for semiconductor lasers is derived as [chang,2003]: where the resonance frequency expression ωr is :       + + == spp rr gp pg f τ ε ετ πω / 0 0 / 1 )1( 2 the second term can be neglected compared to 1( 1〈〈ε ) and the resonance frequency expression reduces to: (5) tj m eiiti ω+= 0)( (6) tj mennn ω+= 0 (7) tj meppp ω+= 0 (8) mm sp m m ppp p gn p pg ev i nj       + + + − + +−= 0 2 0 0 0 0 0 / 1 1 )1( ) 1 1 ( εε ε ετ ω (9) (10) ))(1( )( 22 0 0 / ωγωωε ω jpev pg r r +−+ γ = (11) (12) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 112 )1( 2 0 0 / p pg f p rr ετ πω + == and the damping factor γ can be defined as: the damping rate can be expressed as a function of carrier lifetime and k-factor where {the kfactor can be calculated from the slope of 0p as a function of resonance frequency( rf )}, therefore b. resonance frequency analysis of quantum well laser: in quantum well (qw) lasers, carrier transport (including diffusion, tunneling)has a significant effect on the modulation properties of high-speed lasers (i.e. damping rate) via a reduction of the effective differential gain and usually is a significant limit. therefore in order to obtain a more accurate model it is necessary to include this effect[3,5]. the damping rate exists due to the process of capture and escape of the carriers into and from the qw respectively. thereby, the damping factor does not necessarily vary linearly with photon density. therefore this structure of lasers changes the traditional rate equations due to the different carrier densities in the barrier and the well where the transport factor )/1( ca pesc ττχ += which depends on laser structure{ ca pτ and escτ are the capture and escape time constants respectively) [zhang et al ,2001]. this means by the transport factor we can controlled on the damping rate to get on the better enhanced performance for modulated quantum well laser, this is done by the control of the total width of wells(lq) and the full width of the separate confinement heterostructure (sch) region(lsch), this effects are showing in the pumping current density(jpump) where this current density is injection current of the laser. the carriers in the sch region is described by the diffusion equation:{dd 2 n b(x)/dx 2 – iωn b (x)= 0} where n b(x ) is the carrier distribution in the barrier layers. if the width of barrier layer (lb) is much smaller than the diffusion length (l d ≡ (d/ω)0.5) (as most often is the case) then n b(x) is approximately constant and d is the diffusion constant . in this limit, we can derive a relation between the pump current density jpump, the net current density jnet, and the active carrier density n qc [5,6]: esc ca p schqc b q sch ca pnetpump lind l l l ijj τ τ ωτω +                 ++= 2 1 2 where (13) sp pr g τ τ ε ωγ 1 )( / 2 ++= (14)       += += / 2 2 4 , 1 g wherek kf p p r ε τπ τ γ (15) (16) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 113 }1]/){exp[ 1 , 2 )( ,1/1,),1(, ,)()( ,2 * 2 )( 22 * 000 0 0 ++−± ==         −==+=−=∆ −      ∆ =+−+=−= += ± − − ∞ −+∫ tkeee andf m k e een tkm nnnnjeee dkffj tk e jjjjjjj lll b u z c fph u zu z ee k e ph b phph c f u ff u z b fa b esc em esc a b ca p em ca pescca pnet qbsch c f u f b gh h hπ jcap and jesc are the total capture and escape current densities respectively, emca pj and em escj are the total capture and escape current densities due to longitudinal optical emission respectively , a b ca pj and a b escj are the total capture and escape current densities due to absorption respectively, u ze is the energy of unconfined state, cfe and u fe are the fermi levels for confined and unconfined states ,eph is the phonon energy of occupation carriers densities, nph is the phonon of occupation number, uzk is the wave vector of unconfined state in the z-direction, m * is the effective mass of carriers, ħ=2π/h, h is the plank’s constant, kb is the boltzmann ’s constant ,and t is the temperature of the crystal [tsai, et al,2002]. the capture and escape times constants are ∫ ∞ −+ −= 0 0 )( 1 / 11 u z b u fuca p dkff tk j dednτ ,and tkewheredkff tk j dedn bf u z b c fcesc 〈〈∆−= ∫ ∞ −+ 0 0 )( 1 / 11 τ the ratio c fc u fu esc ca p dedn dedn r / / == τ τ where nu and nc are carriers densities of the unconfined and confined states respectively. if some of carriers are lumped in the sch region into a single , escca pandττ are become e esc e ca pandττ respectively. therefore we can written the expression again as[tsai, et al,2002]: [ ] e esc e ca p qqc e ca pnetpump linijj τ τ ωωτ ++= 1 where         =+= q sch esc ca p e esc e ca p b sch ca p be ca p l l and l l d l τ τ τ τ ττ , 2 2 e ca pτ and e escτ are the effective capture and escape time sonstants. therefore, the modulation response function can be expressed as[zhang, et al ,2001]: (20) ))(1( )( 22 0 0 / ωγωωε χ ω jpev p g r r +−+ γ = (21) (18) (19) (17) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 114 the resonance frequency and damping factor also can be expressed as follows: )1( 2 0 0 / p p g f p rr ετ χ πω + == finally this structure gives rise to the following expression for optical modulation response as a function of frequency: [ ]22222 2 2 )2(1) 2 ()( )( rr r ffff f fr π π γ +    +− = tables (1) and (2) are the parameters values of the ingaas/inp 5nm-qw[3] and with 1.3µm buried hetero structure lasers[agrawal ,2002] respectively results and discussions a. effect of the compression gain (ε) from the tables (1) and (2) and the eqs.(1) and (2) [at steady state (d/dt =0)], figure(2) shows the differential gain (g/ =dg/dt )as the function of the photon density( p) in the ingaas/inp 5nmqw laser compared with 1.3µm buried hetero structure lasers, we are observed that the differential gain is larger in qw laser compared with the semiconductor laser. because of the thickness of qw laser is decreasing compared with the semiconductor laser. therefore, this leads to increase of the quantum confinement of carriers with increasing the photon density. in addition, the differential gain is reduced due to the nonlinear gain effects that it is represented by the gain compression ( ε )where 01 p g g ε+ → . from the eqs. (13) and (22), figure(3)shows the relaxation resonant frequency (fr) as a function of the square root of the photon density ( p ) , we can observed from this figure the relaxation resonant frequency in the qw laser is higher than these frequency in the semiconductor laser . because of the thickness of the qw laser is decreased compared with the thickness of semiconductor laser, and this leads to the quantum confinement of carriers in qw laser is increased with increasing the photon density therefore the differential gain is dominant compared with the nonlinear gain effects .in addition, we can concluded that the damping rate in qw laser is higher than these rate in semiconductor laser as shown in figure(3) where we can calculated the kfactor from figure(3) which it is represented the slope of the curve ,therefore the damping rate as shown in figure(4) (eqs.(15) and (23)) is higher in qw laser than these rate in semiconductor laser which this rate is a function of the k factor. (22) (24) (23)       += += / 2 2 4 , 1 g wherek kf p p r χε τπ τ γ al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 115 b. effect of the capture and escape time constants from the table(1) and eq.(16) , figure(5) shows the net current density ( j net ) as a function of the different energies between the fermi levels for the confined and unconfined states (δef = ef u ef c) , and from eq.(19) , figure(6) shows the ratio r as a function of the δef. we find that when the net current density is changed from 0 to 2ka/cm2 (where the value of jnet =100a/cm2 at near threshold operation and jnet =2ka/cm2 at high power operation), the ratio r is almost constant because of the net current density is large, therefore in this range, we can the obtain on the average values of τcap ,τ cap {from eq.(16) where τcap=∂ jnet/∂nu and τesc = ∂ jnet /∂nc}, and r with different confined carrier density nc (or threshold carrier density )at certain value of vb. therefore from eq.(20), figure(7) shows the ratio r is a function of the quantum wells thickness(lq) at vb=0.2evand nc=4×1012 cm-2,we are observed from this figure the ratio r is depended on the quantum well thickness (i.e is depended on the structure of sch region ),therefore when the ratio r is high (i.e τcap is high )lq is low, this means the capture carriers will still confined in the well ,therefore the modulation response will increase compared with the semiconductor laser as shown in figure( 8 ). but when lq is high the r and lb are low ,this means the capture carrier in well will diffusion in sch region due to ld > lb. conclusions we can enhance of performance of laser system in direct modulation by increase of the carriers quantum confinement in a optical cavity has small size width (quantum well. this leads to reduce the nonlinear gain effects that it is represented by gain compression due to the enhancement of the differential gain by increasing the carriers quantum confinement ). for the control on the gain compression, this is achieving by the control of the capture and escape time constants (i.e the ratio r) ,this means we must change the internal structure of the active region of semiconductor device to the region consists of the confinement and the active regions (separate confinement sch region) where this regions are represented by the potential barrier and quantum well. finally, we can determined the size width of well by selecting the value of the ratio r(when the carriers capture in the well are higher than the carriers escape) but the increasing of carriers capture are limited because the diffusion of carriers capture in the sch region due to diffusion length is greater than potential barrier length . all this to surety the carriers will confine in the well for reduction of non linear gain effects and enhancement of performance of the laser system in the direct modulation. references [1]govind p.agrawal, “fiber-optic communication systems, third edition,sons. inc.,copyright2002. [2] m.h. pua, m.k. haldar, f.v.c. mendis and h.k. garg “reduction of nonlinear distortion in semiconductor lasers with external light injection” , international conference on information, communications and signal processing, icics '97, 2c3.3, singapore, 9-12 september 1997. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 116 [3] p. l. gareso, m. buda, l. fu, h. h. tan, c. jagadish, l. v. dao, x. m. wen, and p.hannaford, "proton irradiation-induced intermixing in inxga1−xas/inp quantum wells—the effect of in composition," semiconductor science and technology, vol. 21 pp. 1441-1446, 2006. [4] c.h. chang, “injection locking of vcsels”, ieee j. of selected topics in quantum electronics, vol. 9, no. 5, sep./oct. 2003. [5] l. zhang, t. f. boggess, k. gundogdu, m. e. flatte, d. g. deppe, c. cao and o. b. shchekin, “excited-state dynamics and carrier capture in ingaas/gaas quantum dots,” appl. phys. lett., vol. 79, pp. 3320-3322, 2001. [6] tsai, c. y., et al., “a small-signal analysis of the modulation response of high-speed quantum well lasers: effects of spectral hole burning, carrier heating, and carrier diffusioncapture-escape,” ieee j. quantum electron., vol. 33, p. 2084-2087,2002. table(1) some parameters values of ingaasp/inp quantum well laser (3) parameter symbol value the full width of the separate confinement heterostructure (sch) region lsch 250 µm current injection efficiency ηi 0.86 interaband relaxation time τin 0.1×10-12 s effective mass of electron /rest mass of electron 0m me 0.11 for x<0.7 0.35 for x>0.7 effective mass of heavy hole/rest mass of electron 0m mhh 0.62+0.05x effective mass of light hole/rest mass of electron 0m mlh 0.11+0.03x quantized energy gap of heavy hole band (confined state) ec = eg(hh) =eg(in0.49 ga0.51 ) –eg (in0.49 ga0.51 p) as shown in fig.(1) quantized energy gap of light hole band (unconfined state) eu = eg(lh) =1eg(hh) as shown in fig.(1) quantum well size lz 5nm the phonon energy of occupation carriers densities, eph 36mev the phonon emission ωo 0.2ps-1 effective barrier height vb 0.2 ev al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 117 table (2) the parameters values of 1.3µm buried hetero-structure laser (1) parameter symbol value active-layer thickness d 0.2 µm cavity length l 250 µm active-region width w 2 µm group velocity c/µg effective refractive index µ 3.4 group refractive index µg 5 carriers recombination lifetime spτ 2.2ns photon lifetime pτ 1.6ps confinement factor г 0.3 threshold current ith 15.8ma fraction of spontaneous emission entering the lasing mode β 107 s-1 gain compression factor ε 3×10-12 m2/s figure 1. band schemes of n-n-n ingaasp/lnp sch sqw structures . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 118 figure 2 the differential gain with respect to the photon density figure 3 the resonant relaxation frequency with respect to (the photon density)0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 x 10 16 1 2 3 4 5 6 7 8 x 10 -6 the photon density(cm-3) t he d iff er en tia l g ai n (c m3 s1 ) for quantum well laser diode for semiconductor laser diode 0 0.5 1 1.5 2 2.5 3 x 10 8 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 x 10 10 (the photon density)0.5(cm-3/2) t he r es on an t re la xa tio n fr eq ue nc y (h z) for quantum well laser diode for sem iconductor laser diode al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 119 figure 4 the damping rate with respect to (the photon density)0.5 figure 5 the net current density as a function δеf 0 0.5 1 1.5 2 2.5 3 x 10 8 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 x 10 11 (the photon density)0.5(cm-3/2) d am pi ng r at e( s1 ) for quantum well laser diode for semiconductor laser diode 0 0.005 0.01 0.015 0.02 0.025 0 500 1000 1500 2000 2500 ∆ef(ev) t he n et c ur re nt d en si ty ( j ne t) (a /c m 2 ) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 120 figure 6 the ratio r is a function of δеf figure 7 the ratio r is a function of the quantum wells thickness 0 0.005 0.01 0.015 0.02 0.025 0.03 0.29 0.3 0.31 0.32 0.33 0.34 ∆e (ev) r = τ c ap / τ es s 5 6 7 8 9 10 11 12 13 14 x 10 -9 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 the quantum well thickness(m) r = τ c ap / τ es s al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 121 figure 8 the response a function of the modulation frequency 10 7 10 8 10 9 10 10 10 11 -40 -30 -20 -10 0 10 20 modulation frequency(hz) r es po ns e( db ) for quantum well laser diode for semiconductor laser diode ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٤ دائري المقطع على انتقال الحرارة بالحمل الطباقي تأثير اتجاهية أنبوب نصف المشترك الحر والقسري حمدي عماد الدين احمد حمدي جامعة األنبار –قسم الهندسة الميكانيكية :الخالصة تم في هذا البحث إجراء دراسة نظرية لبيـان تـأثير اتجاهيـة أنبـوب نصـف دائـري علـى انتقـال الحـرارة بالحمـل شــملت الدراســة منطقــة الــدخول الحــراري .لمشــترك الحــر والقســري مســخن بثبــوت درجــة حــرارة الســطح الطبــاقي ا تضمنت الدراسة حًال عدديًا للمعـادالت الحاكمـة للجريـان وانتقـال الحـرارة لنصـف . وتمام التشكيل الهيدروليكي االســـطوانية تزخم باالتجاهـــااالســـتمرارية ، الطاقــة ، والـــ(أنبــوب دائـــري مائـــل باســتعمال المعـــادالت األساســـية r )φ ,الـثالث z , ( بعـد أن اختزلـت إلـى أربـع معـادالت ال بعديـة هـي معادلـة الطاقـة ومعادلـة الـزخم باإلتجـاه القطــري والمماســي ومعادلــة الــزخم باإلتجــاه المحــوري ومعادلــة الدواميــة حيــث كانــت المتغيــرات فيهــا هــي درجــة الجريــان والســرعة المحوريــة وتــم تحويلهــا الــى الصــيغة الالبعديــة بداللــة كــًال مــن عــدد كراشــوف ، الحــرارة ودالــة . برانتــل ، رينولــدز وعــدد رايلــي ، وحلــت هــذه المعــادالت عــدديًا بإســتخدام الطريقــة اإلرتحاليــة وطريقــة كــاوس فـــي منطقـــة النمـــو أســـتخرجت نتـــائج الحلـــول العدديـــة لألنبـــوب نصـــف الـــدائري بثبـــوت درجـــة حـــرارة الســـطح الحراري حيث مثلت النتائج لقيم مختلفة من زوايا ميل القناة ولقـيم عـدد رايلـي متغيـرة بمخططـات دالـة الجريـان ودرجة الحـرارة وتوزيـع قـيم عـدد نسـلت الموضـعية حـول محـيط القنـاة وتغيـر قـيم عـدد نسـلت المعـدل بتغيـر قـيم ن الثــانوي النـاتج عــن الحمــل الحـر لــه تــأثير هـام علــى عمليــة بينـت نتــائج الحــل العـددي إن الجريــا. عـدد رايلــي انتقــال الحــرارة وان أعظــم تــأثير لــه يكــون عنــد الموضــع األفقــي للقنــاة ويتنــاقص تــأثيره بزيــادة مــيالن القنــاة إلــى . الوضع العامودي ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٥ influence of semi-tube orientation on combined free and forced laminar convection heat transfer hamdi e. ahmed hamdi mechanical engineering department, university of anbar abstract : a theoretical study has been conducted on the influence of semi-tube orientation on combined free and forced laminar convection heat transfer where the semi-tube heated with constant surface temperature. the theoretical study was done for both the thermal entrance region and hydraulically fully developed region. theoretically the governing equations for a flow through an inclined semi-tube were reduced to four, which are continuity equation, radial and tangential momentum equations, axial momentum equation and vorticity equation in which the variables where the temperature, vorticity, stream function and axial velocity. these equations were reduced to dimensionless equations in which grashof, prandtl, reynolds and rayleigh numbers were presented. these equations were numerically solved by using the marching process explicit finite difference method and gauss elimination technique. numerical results for the inclined semi-tube heated by constant surface temperature in the thermal entrance region were obtained and represented by stream function contours and isotherms for different values of rayleigh and channel angle, as well as the circumferential distribution of local nusselt number and the change of average nusselt number with rayleigh number. the results clarify the significant effects of the secondary flow created by natural convection on the heat transfer process, reveal an increase in the nusselt number as the angle of inclination moves from the vertical to the horizontal position. ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٦ a ، 2المساحةm a نصف قطر القناة ،m cp عند ثبوت الضغط السعة الحرارية ،kgkj / hd القطر الهيدروليكي،m g 2 ،التعجيل األرضي/ sm h معامل إنتقال الحرارة بالحمل، kmw ./ 2 k خطوة االزاحة باالتجاه المحوريz fk الموصولية الحرارية للمائع،kmw ./ l الطول،m m خطوة اإلزاحة باالتجاه نصف القطريr n خطوة اإلزاحة باالتجاه المماسيφ p الضغط الالبعدي zp هبوط الضغط باإلتجاه المحوري الالبعدي، 2/ mn p ، 2الضغط/ mn اإلحداثيات االسطوانية الالبعدية α زاوية ميل القناة β ، معامل التمدد الحجمي k/1 υ اللزوجة الكينماتية( )ρµ / ، sm /2 θ درجة الحرارة الالبعدية µ اللزوجة الديناميكية،smkg ./ ρ ، 3الكثافة الكتلية/ mkg τ الزمن الالبعدي ψ دالة االنسياب الالبعدية ψ دالة االنسياب،sm /2 ω الدوامية الالبعدية ω الدوامية،s/1 االعداد الالبعدية الالتينيةالرموز الرموز المستخدمة المقدمة الحمـــل داخـــل أنبـــوب نصـــف دائـــري يتـــأثر بشـــكل واضـــح بوجـــود قـــوى الجاذبيـــة إن معامـــل انتقـــال الحـــرارة ب خصوصًا عند معدالت جريان منخفضة ، إذ إن اتجاهيـة األنبـوب تـؤثر بشـكل مباشـر علـى منحنيـات السـرعة ودرجــة الحــرارة المصــاحبين لعمليــة انتقــال الحــرارة ، حيــث إن األنبــوب ذو الوضــع األفقــي يحصــل عنــده تعامــد ي قوى الطفو واتجاه الجريان الرئيسي والذي بدوره يولد تيارات الجريان الثانوي العامودية على اتجاه بين اتجاه الجريـــان الرئيســـي ، علـــى العكـــس مـــن ذلـــك لحالـــة األنبـــوب العـــامودي فيحـــدث تطـــابق اتجـــاهي كـــل مـــن قـــوى بين تلــك الحــالتين فــان الجاذبيــة والجريــان الرئيســي وهــو مــا يــؤثر بشــكل مباشــر بعــدم تولــد جريــان ثــانوي ومــا ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٧ األنبوب المائل وتأثير زاوية ميلـه علـى معـدل الحـرارة المنتقلـة بالحمـل لـم تـدرس بشـكل وافـي لجميـع زوايـا ميـل فــي الواقــع العملــي فــان حالــة األنبــوب المائــل شــائعة االســتخدام فــي المبــادالت الحراريــة والمجمعــات . األنبــوب . لى زاوية سقوط أشعة الشمس على المجمع الشمسي الشمسية المسطحة التي يعتمد اتجاهها ع مــن الدراســات العمليــة والنظريــة المبكــرة التــي تطرقــت لموضــوع انتقــال ) finn )1970و allenتعتبــر دراســة الحــرارة بالحمــل المخــتلط فــي القنـــوات العاموديــة دائريــة المقطــع حيــث اســـتخدما الــنفط كمــائع جريــان ذو عـــدد األخــذ باالعتبــار تغيــر الخــواص الفيزيائيــة للمــائع مــع التغيــر الحاصــل فــي درجــة الحــرارة ، برانتــل مرتفــع وتــم بدراسته النظرية النتقال الحـرارة بالحمـل المركـب الحـر والقسـري ) raghavacharyulu )1985تبعهما الباحث مسـامية حيـث سـخنت وأيضًا لقناة دائرية المقطع عاموديـة غيـر أن المـادة المصـنع منهـا األنبـوب كانـت مـادة هــذه القنــاة بثبــوت الفــيض الحــراري عنــد الســطح وحلــت المعــادالت الحاكمــة للســرعة ودرجــة الحــرارة باســتخدام صيغة متسلسالت فورير مع استخدام تقريب بويسنسك لمعالجـة حـد الطفـو وفـرض الجريـان طبـاقي وتـام النمـو وزمالئـه بدراسـة عمليـة ونظريـة النتقـال ) tanaka et al. )1987الهيـدروليكي والحـراري ، ومـن ثـم قـام الباحـث الحـرارة بالحمــل المخـتلط داخــل قنـاة دائريــة المقطـع عاموديــة مسـخنة بثبــوت الفـيض الحــراري وفـي منطقــة تمــام النمــو الهيــدروليكي والحــراري مــع اســتخدام غــاز النيتــروجين المضــغوط كمــائع اختبــار فــي الجانــب العملــي مــن )حثون أعـــاله مـــدى واســـع مـــن عـــدد رينولـــدز تـــراوح بـــين الدراســـة ، اســـتخدم البـــا )5000re3000 لينتقـــل ≥≥ الجريان مابين الطباقي والجريان المضطرب ، في حـين كـان تغيـر شـكل مقطـع الجريـان إلـى الشـكل البيضـوي تغير وفي طور ). lasode )2007 ولنفس الوضع العامودي هو موضوع الدراسة النظرية التي أجراها الباحث وزمالئه بدراسة نظرية وعمليـة النتقـال الحـرارة بالحمـل ) nyce et al. )1992شكل مقطع الجريان قام الباحث المخــــتلط فــــي قنــــاة مســــتطيلة أفقيــــة مســــخنة مــــن أســــفلها ومبــــردة مــــن أعالهــــا لحالــــة عــــدد رايلــــي ثابتــــة عنــــد ( )20022=ra ولنسبة شكل)aspect ratio=2 (راسة معرفة تأثير الحمل الطبيعي على توزيع تم في هذه الد . السرعة المحورية في منطقة الدخول الحراري و iqbalالباحثان ) 1966(أما انتقال الحرارة بالحمل المختلط في القنوات المائلة فقد بدء دراستها نظريًا عام stachiewicz خـالل قنـاة دائريـة مائلـة سـخنت بثبـوت بدراسة طبيعة الجريان وانتقـال الحـرارة بالحمـل المخـتلط الفــيض الحــراري عنــد الســطح وفــرض الباحثــان الجريـــان طباقيـــُا وتـــام النمـــو الهيدروليكـــي والحــراري واســتعمال تقريــب بويسنســك لبيــان تــأثير قــوة الطفــو كمــا ووجــد الباحثــان إن أعظــم قيمــة لعــدد نســلت تحصــل عنــدما تكــون )زاوية ميل األنبوب )αواقعة بين( )oo 3035 )في حالة جريان الهـواء وبمـدى − )oo 2040 لحالـة جريـان المـاء − إذ درســا ) patankar )1988و choudhuryتبعــت هــذه الدراســة مــا قــام بــه الباحثــان . فــي األنبــوب المائــل ئريــة المقطــع مائلــة سخـــنت بثبــوت درجــة حــرارة الســطح ، تحليليـــًا انتقــال الحــرارة بالحمـــل المخــتلط فــي قنــاة دا شــملت الدراســة منطقــة الــدخول الهيــدروليكي والحــراري وحصــل الباحثــان علــى النتــائج لموائــع ذات عــدد برانتــل ( )10,5,7.0pr لـم تظهـر زاويـة الميـل . وحلت المعادالت الحاكمة عدديًا باستخدام طريقة الفروقـات المحـددة = ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٨ ( )α كمتغير صـريح فـي المعـادالت الحاكمـة للجريـان وانتقـال الحـرارة وٕانمـا تـم تضـمينها ضـمن العامـل الحـاكم )عدد رايلي المعدل )∗ra أظهرت الدراسة مدى تأثير الجريان الثـانوي فـي مواضـع متعـددة مـن مجـرى المـائع ، و bello-ochendeكــــذلك فقــــد قــــام الباحثــــان . رارة بالحمــــل المخــــتلط فــــي األنبــــوب المائــــل علــــى انتقــــال الحــــ adegun )2004 ( فــي مجــال القنــاة المائلــة دراســة عدديــة النتقــال الحــرارة بالحمــل المخــتلط مضــافًا إليــه تــأثير اإلشعاع لجريان طباقي بين قنـاة مربعـة المقطـع تـدور حـول محـور الجريـان ثبـت داخلهـا قنـاة دائريـة المقطـع ، فقـــد أجـــرى دراســـة عمليـــة ونظريـــة النتقـــال الحـــرارة بالحمـــل المخـــتلط فـــي ) mohammed )2005مـــا الباحـــث أ مجــرى حلقــي ســخنت االســطوانة الداخليــة لكــل مــن ظرفــي التســخين بينمــا عزلــت االســطوانة الخارجيــة حراريــًا ، ائج علـى شـكل مخططـات حلت المعادالت الحاكمة عدديًا باسـتخدام طريقـة الفروقـات المحـددة واسـتخرجت النتـ )دالة االنسياب وتوزيع درجات الحرارة وعدد نسلت الموضعي لمدى متغير من زاوية ميل القناة )α. الجانب النظري :تم استخدام الفرضيات اآلتية لغرض تبسيط الحل العددي مع مالحظة عدم التأثير بالحل العام ودقته ) .fully developed(غير انزالقي وتام النمو الهيدروليكي الجريان – 1 ) .heat source(عدم وجود مصدر حراري – 2 . عدم تغير قيم الحرارة النوعية والموصولية الحرارية واللزوجة بتغير درجات الحرارة – 3 لحالــة المدروســة فــي معادلــة الطاقــة ل) viscous dissipation term(يمكــن إهمــال حــد تبــدد اللزوجــة – 4 . لكون السرعة قليلة ). assistants flow(الجريان بإتجاه األعلى فقط – 5 إذ أن الكثافــة تعــد ثابتــة ماعــدا فــي حــد قــوة الطفــو إلن حركــة ) boussinesq(إعتمــاد فرضــية بويسنســك – 6 :المائع تعتمد على تغير الكثافة ولذلك يمكن وصف تغير كثافة المائع بالصيغة اآلتية ( )[ ]τ−τ−= wwf βρρ 1 (1) ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٩ )الجريان ثنائي البعد – 7 )φ,r متناظر حول المستوي العامودي الذي يمـر فـي مركـز النظـام ، وبـذلك يمكـن . من النظام دراسة جانب واحد بنــاًء علــى الفرضــيات المــذكورة أعــاله فــإن معادلــة اإلســتمرارية يمكــن التعبيــر عنهــا باإلحــداثيات القطبيــة كمــا ):crawford )1993و kaysيأتي ( ) 011 = ∂ ∂ + ∂ ∂ φ v r ur rr (2) )وتكــون معــادالت الــزخم باإلحــداثيات القطبيــة )φ,r واإلحــداثي المحــوري( )z علــى التــوالي كــاآلتيkays و crawford )1993 : (    ∂ ∂ −   − ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      − ∂ ∂ + ∂ ∂ φφ µ φ ρ v rr uu rr u rr u r p r vu r v r u u 222 2 22 22 211 ( )αφρ coscosg− (3a)    − ∂ ∂    + ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      + ∂ ∂ + ∂ ∂ 222 2 22 2 211 r vu r v rr v rr v r p r vuv r v r v u φφ µ φφ ρ ( )αφρ cossing+ (3b) αρ φ µ φ ρ sin 11 2 2 22 2 g w rr w rr w z pw r v r w u −       ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      ∂ ∂ + ∂ ∂ (3c) )وتأخذ معادلة الطاقة باإلتجاهات المحورية الثالث )zr ,,φ الصيغة اآلتيةkays وcrawford )1993: ( z w rr r rr k r v r u f ∂ τ∂ −      ∂ τ∂ +      ∂ τ∂ ∂ ∂ = ∂ τ∂ + ∂ τ∂ 2 2 2 11 φφ (4) )معــادلتي الــزخم بإتجــاهي يــتم الــتخلص مــن حــد الضــغط مــن )φ,rوٕاذا . بالتفاضــل المتقــاطع بــين مركبتــي الــزخم : عرفنا دالة اإلنسياب باإلحداثيات القطبية كاآلتي φ ψ ∂ ∂ = r u و 1 r v ∂ ∂ −= ψ بـذلك تختـزل معادلـة الـزخم إلـى :الصيغة اآلتية αφ φ φ β φ υ φ ψ φ ψ cossin cos111 2 2 22 2       ∂ τ∂ + ∂ τ∂ +      ∂ ω∂ + ∂ ω∂ + ∂ ω∂ =      ∂ ω∂ ∂ ∂ − ∂ ω∂ ∂ ∂ rr g rrrrrrr (5) ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٠ φ∂ ∂ −+ ∂ ∂ =ω u rr v r v 1 مرهقـًا حسـابيًا تسـتخدم فرضـية إضـافة حـد التغيـر ) .elliptic d. e(لكون الحل المباشر لمعـادالت القطـع النـاقص لتتحــول مــن معــادالت قطــع نــاقص إلــى ) 5(و ) 3b(و ) 3a(مــع الــزمن إلــى الجانــب األيســر مــن المعــادالت بالحل العـام للمعـادالت وتسـهله إلـى حـد كبيـر وهي فرضية ال تخل) .parabolic d. e(معادالت قطع مكافئ )، وعليه ستأخذ معادلة الزخم باإلتجاه المحوري )z الشكل اآلتيkays وcrawford )1993: ( αρ φ µ φ ψ φ ψ ρ sin 1111 2 2 22 2 g w rr w rr w z pw rrr w rt w −       ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      ∂ ∂ ∂ ∂ − ∂ ∂ ∂ ∂ + ∂ ∂ (6) )وتأخذ معادلة الزخم باإلتجاه )φ,r الشكل اآلتي: αφ φ φ β φ υ φ ψ φ ψ cossin cos111 2 2 22 2       ∂ τ∂ + ∂ τ∂ +      ∂ ω∂ + ∂ ω∂ + ∂ ω∂ =      ∂ ω∂ ∂ ∂ − ∂ ω∂ ∂ ∂ + ∂ ω∂ rr g rrrrrrrt (7) ) :crawford )1993و kaysفي حين تأخذ معادلة الطاقة الشكل اآلتي z w rr r rr k rrrrt f ∂ τ∂ −      ∂ τ∂ +      ∂ τ∂ ∂ ∂ = ∂ τ∂ ∂ ∂ − ∂ τ∂ ∂ ∂ + ∂ τ∂ 2 2 2 1111 φφ ψ φ ψ (8) :مع مالحظة إن معادلة الدوامية باإلحداثيات القطبية تكون بالصيغة اآلتية ω−=∇ ψ2 (9) (10) العوامل الالبعدية اآلتية وبتعريف 〉〈 = w w w ، t a w 〉〈 =τ ، a r r = ، 〉〈 =ψ wa ψ 〉〈 = w p p ρ ، prrea z =ζ ، ω 〉〈 = w a ω ، wi w τ−τ τ−τ =θ ، g w a g 2〉〈 = zpوتعويضها في معادالت الزخم والطاقة مع مالحظة أن z p = ∂ :وبتبسيطها ينتج ∂ ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١١ α φφτ sin re 11 2 gwp w rr w r w z −∇+−=      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ + ∂ ∂ (11) α θ φ φ θφ ω φ ωω φτ ω cossin cos prrere 11 2 2       ∂ ∂ + ∂ ∂ +∇=      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ + ∂ ∂ rr ra rrr (12) ثابــت علــى طــول محــور القنــاة لــذلك ) pressure drop(يهمــل إنحــدار الكثافــة المحــوري لكــون إنحــدار الضــغط mohammed )2005: ( zpww ˆ= (13) )على ) 11(بقسمة معادلة )zp فيها ينتج ) 13(وتعويض معادلة: α φφτ sinˆ re 1 1 ˆˆ1 2 gw w rr w r w −∇+−      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ −= ∂ ∂ (14) )بما إن معدل السرعة يبقى ثابتًا فإن إنحـدار الضـغط المحـوري )zp يأخـذ صـيغة التكامـل اآلتـيmohammed )2005:(       = ∫ ∫ 2/ 0 1 0 ˆ2/ π φπ ddrrwpz (15) :أما معادلة الطاقة بعد تعويض العوامل الالبعدية فيها والتبسيط فتصبح w rrr prre 1 prre 11 2 −∇=      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ + ∂ ∂ θ φ θθ φτ θ (16) الشروط الحدية :ف الحدية لألنبوب نصف الدائري في حالة اإلستقرار تكون كاآلتي الظرو )السرعة المحورية – 1 ) 00,,ˆ =φrw ( ) ( ) ( ) ( ) 0,,ˆ,0,ˆ,,1ˆ,,0ˆ ==== zrwzrwzwzw πφφ )درجة الحرارة – 2 ) 10,, =φθ r ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٢ ( ) ( ) ( ) ( ) 0,,,0,,,1,,0 ==== zrzrzz πθθφθφθ ( ) 0,, 2 =∂ ∂ zr π φ θ ) دالة اإلنسياب – 3 ) 00,, =ψ φr ( ) ( ) ( ) ( ) 0,,,0,,,1,,0 =ψ=ψ=ψ=ψ zrzrzz πφφ ( ) 0,, 2 =∂ ψ∂ zr π φ ) الدوامية – 4 ) 00,, =φω r ( ) ( ) ( ) ( ) 2 2 2 2 ,,1 ,,1, ,,0 ,,0 r z z r z z ∂ ψ∂ −= ∂ ψ∂ −= φ φω φ φω ( ) ( ) ( ) ( ) ( ) 0,,,,,,,,,0,,0, 222 2 22 2 = ∂ ψ∂ −= ∂ ψ∂ −= zr r zr zr r zr zr πω φ π πω φ ω الحل العددي للمعادالت الحاكمة )تقســـم منطقـــة الجريـــان المحـــددة باإلحـــداثيات القطبيـــة )φ,r كمـــا مبـــين بالشـــكل)b-1 ( إذ تكـــون التقســـيمة )ألبعاد اآلتية الواحدة با )φ∆×∆ r . إن عدد التقسيمات الشبكية في هذه الحالـة سـيكون( )ntmt فـي حـين × )ســتكون ) ( )( )11 +×+ ntmt مــن العقــد الشــبكية وذلــك لنصــف منطقــة الجريــان لوجــود ظــاهرة تماثــل الجريــان يمكـــن الحصـــول علـــى الحـــل بداللـــة درجـــة الحـــرارة ودالـــة . حـــول المحـــور العـــامودي لنصـــف األنبـــوب الـــدائري اإلنسياب والدوامية والسرعة المحورية من الحـل العـددي للمعـادالت الحاكمـة مـع الشـروط الحديـة المرتبطـة بهـا وبعــد تحويــل المعــادالت التفاضــلية إلــى جبريــة بصــيغة الفروقــات المحــددة . بإسـتخدام طريقــة الفروقــات المحــددة )ل علـــــى معـــــادالت الطاقـــــة والـــــزخم باإلتجـــــاه المحـــــوري والـــــزخم باإلتجـــــاهين وبالتبســـــيط نحصـــــ )φ,r اآلتيـــــة anderson )1995: ( ( ) k nm k nm k nm wtt ,,21 1 , prre 1 θτθ +∆−+−=+ (17) k nm k z k nm w p gt tw , 4 3 1 , ˆsin re 1ˆ +∆−+−−=+ τα (18) ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٣ k nm k k nm ra t t t ,27 6 5 1 , cos prrere ωταω +∆++−=+ (19) .ت الحاكمة بعد التحويل إلى الصيغة الالبعديةأي حدود المعادال) term(يعني ) t(حيث أن الرمز عة المحوريةحساب متوسط السر : من حساب اآلتي bwيمكن حساب قيمة متوسط السرعة المحورية πφ π /ˆ 0 1 0       = ∫ ∫ ddrrwwb (20) حساب عدد نسلت الموضعي : المعادلة اآلتية يحسب عدد نسلت من k b k w k n nu θ θ    ∂ ∂ −= ˆ (21) ) :crawford )1993و kaysللسطح المستوي من األنبوب نصف الدائري فإن ww n     ∂ ∂ =   ∂ ∂ φ θθ ˆ ) : crawford )1993و kaysأما للسطح المنحني من األنبوب نصف الدائري فإن ww rn     ∂ ∂ =   ∂ ∂ θθ ˆ :تحسب من التكامل اآلتي bθكذلك فإن درجة الحرارة الظاهرية ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٤             = ∫∫ ∫ ∫ π π φ φθ θ 0 1 0 0 1 0 ˆ ˆ ddrrw ddrrw b (22) يمكــن ) 22(البعديــة وتعــويض تلــك القــيم فــي المعادلــة عــدديًا وٕاســتخراج قــيم درجــة الحــرارة ال) 17(بحــل المعادلــة ) .21(وبالتالي حساب عدد نسلت الموضعي من المعادلة bθاستخراج درجة الحرارة الظاهرية النتائج والمناقشة ائــل مثلــت بعــدد إن الحــل العــددي لمعــادالت الــزخم والطاقــة لجريــان المــائع خــالل نصــف األنبــوب الــدائري الم من المخططات الكنتورية لدالة االنسياب وخطـوط تسـاوي درجـة الحـرارة للمقطـع العرضـي لحقـل الجريـان ولقـيم مختلفة من عدد رايلي ولزويا ميل تتغير من الوضع األفقي إلى الوضع العامودي في منطقة التشكيل الحراري )ة لقيم زوايا ميل ، كما وتم إيجاد تغير متوسط عدد نسلت على محيط القنا )α متغيرة ولمدى واسع من أعداد .رايلي ) الجانـــب األيســـر(ودرجـــة الحـــرارة ) الجانـــب األيمـــن(يمثـــل المخطـــط الكنتـــوري لدالـــة االنســـياب ) 2(الشـــكل )لمواضع متغيرة من القنـاة تراوحـت بـين )075.001.0 ≤≤ z ولخمـس زوايـا ميـل( )°≤≤° 900 α بثبـوت عـدد )رايلي عند )410=ra . تم بيان تأثير زاويـة مـيالن القنـاة علـى دالـة االنسـياب بمالحظـة العـامود المتكـون مـن )بثبــوت المســافة باالتجــاه المحــوري عنــد ) الجانــب األيمــن(خمــس مقــاطع )01.0=z وتغيــر زاويــة الميــل ، إذ الجريان الثانوي يكون ذا تأثير واضح للقناة األفقية بينما يتناقص هذا التـأثير كلمـا زادت زاويـة ميـل يالحظ إن كمـا و يمكـن مالحظـة . القناة إلى أن يضمحل وجـود الجريـان الثـانوي عنـد تحـول القنـاة إلـى الوضـع العـامودي )تــــأثير زاويــــة ميــــل القنــــاة )α بأخــــذ الموضــــع ) الجانــــب األيســــر(الحــــرارة للمــــائع علــــى خطــــوط تســــاوي درجــــة ( )05.0=z علــى ســبيل المثــال حيــث يالحــظ إن مركــز الكتلــة البــاردة للمــائع فــي قلــب القنــاة للحالــة العاموديــة ( )°= 90α شــدة الجريــان أمــا . يقتــرب مــن قاعــدة القنــاة كلمــا قلــت زاويــة ميــل القنــاة وصــوًال إلــى الوضــع األفقــي الثــانوي مــن مــدخل القنــاة إلــى منطقــة تمــام التشــكيل الحــراري والهيــدروليكي فــيمكن مالحظتــه بمتابعــة الجانــب )األيمن من الصف الثاني المتكون من أربع مقاطع للقناة بثبوت زاوية الميل عند )°= 30α حيـث تراوحـت قـيم )دالة االنسياب مـابين )0081.00081.0 ≤ψ≤− إذ تكـون دالـة االنسـياب للموضـع األول ،( )01.0=z بشـدة )متوسطة ترتفع لتصـل إلـى قيمتهـا العظمـى فـي الموضـع الثـاني )025.0=z ومـن ثـم تقـل هـذه الشـدة إلـى أن جــات الحــرارة علــى أمــا توزيــع در . تتالشــى فــي الموضــعين الثالــث والرابــع فــي منطقــة تمــام التشــكيل الحــراري الجانــب األيســر مــن الشــكل فيكــون المــائع فــي الموضــع األول ذو درجــة حراريــة قريبــة مــن درجــة حــرارة المــائع الــداخل إلــى القنــاة بينمــا تســخن طبقــات المــائع القريبــة مــن الجــدار تــدريجيًا كلمــا تقــدم الجريــان إلــى أن يصــبح ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٥ )اة فــي الموضــع األخيــر مــن القنــاة المــائع بدرجــة حراريــة مقاربــة لدرجــة حــرارة ســطح القنــ )075.0=z . الشــكل يمثـــــل المخطـــــط الكنتـــــوري لدالـــــة االنســـــياب ودرجـــــة الحـــــرارة لمواضـــــع مختلفـــــة مـــــن القنـــــاة تراوحـــــت بـــــين )3( ( )07.0004.0 ≤≤ z ولــــــــنفس زوايــــــــا الميــــــــل الســــــــابقة( )°≤≤° 900 α بزيــــــــادة عــــــــدد رايلــــــــي ليصــــــــل إلــــــــى ( )4105 ∗=ra . تــم بيــان تــأثير زيــادة عــدد رايلــي علــى الجريــان الثــانوي وتوزيــع درجــة الحــرارة داخــل القنــوات المائلـــة حيـــث تســـبب الزيـــادة فـــي عـــدد رايلـــي تعاظمـــًا فـــي شـــدة الجريـــان الثـــانوي لتتـــراوح قيمـــة دالـــة االنســـياب ( )0127.00127.0 ≤ψ≤− طول الدخول الحراري حيث تكون التطورات وأيضًا تؤدي تلك الزيادة إلى تقصير إن مقطـع القنـاة الـذي . )2(الشـكل الحاصلة في قـيم دالـة االنسـياب اقـرب إلـى مـدخل القنـاة ممـا هـو عليـه فـي تحصــل فيــه القيمــة العظمــى لدالــة االنســياب يبتعــد عــن مــدخل القنــاة كلمــا زادت زاويــة ميــل القنــاة ، كــذلك فــان يـؤدي إلـى تسـارع تحـول درجـة حـرارة المـائع قريبـًا مـن درجـة حـرارة سـطح )3(كل الشتأثير رفع عدد رايلي فـي .القناة المائلة بفعل زيادة تأثير الحمل الحر المولد لتيارات الجريان الثانوي )فقد اشتركا في نفـس سـلوك دالـة االنسـياب لحالـة القنـاة العاموديـة )3(و )2( الشكلينأما )°= 90α حيـث )ينعدم وجود تيارات الجريان الثانوي )0=ψ كما وان خطوط تسـاوي درجـة الحـرارة تصـبح ذو شـكل منحنيـات .تأخذ نفس الشكل النصف دائري للقناة وتكون متحدة المركز سـع مـن أعـداد يمثل تغير معدل عدد نسلت على طول القناة المائلة لزوايـا ميـل متغيـرة ولمـدى وا )4(الشكل )رايلي تراوحت بين )53 10510 ∗≤≤ ra يظهر السلوك العام لتأثير تغير عدد رايلي . لكل زاوية ميل عل حدة علــى ســبيل المثــال حيــث تكــون زاويــة ميــل القنــاة لهــذه الحالــة )b-4(الشــكل بثبــوت زاويــة الميــل مــن مالحظــة ( )°= 30α تغيــر عــدد نســلت علــى طــول القنــاة عنــد عــدد رايلــي )1(رقــم إذ يمثــل المنحنــي( )310=ra حيــث يكون تأثير عدد رايلي غير محسوس على معدل الحرارة المنتقلة بالحمل المشترك وتصبح مقاربة لحالة الحمل )القســري الخــالص ، أمــا بزيــادة عــدد رايلــي إلــى )3105 ∗=ra يــادة فــي معــدل عــدد تحــدث ز ) 2(المنحنــي رقــم نسلت في منطقة الدخول الحراري بفعل التأثير المهـم لتيـارات الجريـان الثـانوي الناشـئة مـن الحمـل الحـر علـى الحمـــل القســـري ممـــا يـــؤدي إلـــى زيـــادة ملحوظـــة فـــي معـــدل الحـــرارة المنتقلـــة بالحمـــل المشـــترك الحـــر والقســـري قيمـة عـدد رايلـي ليبـدأ هـذا السـلوك باالضـطراب عنـد زيـادة ويتصاعد هذا التأثير للجريان الثانوي كلمـا ارتفعـت )عــدد رايلــي لمــا فــوق )510>ra فــي الموضــع ) 1-7(مــن ثــم تلــتحم جميــع المنحنيــات( )5.0=z حيــث يمثــل جريـــان هـــذا الموضـــع وصـــول الجريـــان إلـــى منطقـــة تمـــام التشـــكيل الحـــراري إذ يتالشـــى عنـــدها تـــأثير تيـــارات ال .الثانوي :لمعرفة تأثير زاوية ميل القناة على معدل الحرارة المنتقلة فيمكن تثبيت النقاط التالية )يظهــر التــأثير الضــئيل لزاويــة ميــل القنــاة )4(الشــكل فــي جميــع حــاالت ) 1(بمالحظــة المنحنــي رقــم – 1 )α )المشترك عند أعداد رايلي واطئة اقل من على معدل الحرارة المنتقلة بالحمل )310<ra . ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٦ ومقارنتهـا مـع المنحنيـات ذاتهـا الموجـودة )4(الشـكل فـي كـل حالـة مـن ) 3(و ) 2(، ) 1(بجمع المنحنيـات – 2 قلـة لحاالت زوايا ميـل أخـرى يتبـين لنـا إن المنحنيـات الثالثـة تتقـارب مـن بعضـها وتتنـاقص معـدل الحـرارة المنت )بالحمــل المشــترك مــع زيــادة عــدد رايلــي كلمــا زادت زاويــة ميــل القنــاة )α لتنطبــق جميــع هــذه المنحنيــات علــى لحالة القناة العامودية حيث ينعدم تـأثير زيـادة عـدد رايلـي علـى معـدل انتقـال الحـرارة )e-4(الشكل بعضها في . بالحمل المشترك اب فــي تخمــين معــدل الحــرارة المنتقلــة بالحمــل علــى طــول القنــاة المائلــة كلمــا زاد عــدد تظهــر حالــة االضــطر – 3 )رايلي عـن )510>ra وتـزداد قيمـة عـدد رايلـي التـي يضـطرب عنـدها سـلوك كميـة الحـرارة المنتقلـة كلمـا زادت )زاويــة ميــل القنــاة لتصــل إلــى )5102 ∗=ra القنــاة عنــدما تكــون زاويــة ميــل( )°= 60α ويمكــن مالحظــة ذلــك . )4(الشكل في جميع حاالت ) 6(بمقارنة المنحني رقم االستنتاجات .تزداد كمية الحرارة المنتقلة بالحمل كلما تحول وضع القناة المائلة من الوضع العامودي إلى الوضع األفقي – 1 .عدد رايلي وثبوت زاوية ميل القناة يقل طول منطقة الدخول الحراري بزيادة – 2 )يزداد طول منطقة الدخول الحراري بزيادة زاوية ميل القناة ماعدا القناة ذات الوضع العامودي 3 )°= 90α. يكون التباين بتوزيـع درجـات الحـرارة لمقطـع الجريـان فـي قيمـه العظمـى عنـد الوضـع األفقـي للقنـاة ويقـل هـذا – 4 ن تدريجيًا بزيادة زاوية ميـل القنـاة ، فـي حـين تتحـول خطـوط تسـاوي درجـة الحـرارة علـى بعـد متسـاوي مـن التباي .جميع جدران القناة و بشكل منحنيات متحدة المركز لحالة القناة العامودية )لحالــة القنــاة العاموديــة – 5 )°= 90α رك مهمــا تــم رفــع قيمــة عــدد ال تتــأثر كميــة الحــرارة المنتقلــة بالحمــل المشــت .رايلي المصادر • adegun, i. k. and bello-ochende, f. l., "mixed convection and radiative heat transfer in an inclined rotating rectangular duct with a centered circular tube", j. of the braz. soc. of mech. sci. and eng., vol. xxvi, no. 3, pp. 323-329(2004). ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٧ • allen, p. h. g. and finn, a. h., "profile development with mixed convection in a high prandtl number fluid", j. heat mass transfer, pp. 299-304(1970). • anderson, j. d., "computational fluid dynamics", mcgraw-hill inc. (1995) . • choudhury, d. and patankar, s. v., "combined forced and free laminar convection in the entrance region of an inclined isothermal tube", j. of heat transfer asme trans., vol. 110, pp. 901-910(1988). • iqbal, m. and stachiewicz, j. w., "influence of tube orientation on combined free and forced convection heat transfer", j. of heat transfer asme trans., pp. 109-116(1966). • kays, w. m. and crawford m. e. , "convective heat and mass transfer", 3rd edition , mcgraw hill inc. (1993) . • lasode, o. a., "mixed convection heat transfer in rotating vertical elliptic ducts", j. of the braz. soc. of mech. sci. and eng., vol. xxix, no. 2, pp. 142-151(2007). • mohammed, a. a., "an investigation into laminar convection heat transfer through concentric annuli", ph. d. thesis, university of technology (2005). • nyce, t. a., ouazzani, j., durand-daubin, a. and rosenberger, f., "mixed convection in a horizontal rectangular channel – experimental and numerical velocity distributions", int. j. heat mass transfer, vol. 35, pp. 1481-1493(1992). • raghavacharyulu, n. ch., "combined free and forced convection in vertical circular porous channel", indian j. pure appli. math., vol. 16, pp. 323-328(1985). • tanaka, h., maruyama, s. and hatano, s., "combined forced and natural convectionheat transfer for upward flow in a uniformly heated vertical pipe", int. j. heat mass transfer, vol. 30, no. 1, pp. 165-174(1987). ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٨ التمثيل الفيزيائي -a أنبوب نصف دائري مائل) 1(شكل -b-التمثيل الشبكي لمنطقة الجريان 1 2 3 mt+1 1 2 3 nt+1 . (m,n) n ∆ φ ∆r m -a -b α g zr φ , w , u , v channel cross section اتجاه الجريان semi-tube cross section ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٩ -a-b -c-d aزاوية ميل القناة تغير معدل عدد نسلت على طول القناة لقيم متغيرة من عدد رايلي وتغير ) 4(شكل ( )o0=α ،b ( )o30=α ،c ( )o45=α ،d ( )o60=α ،e ( )o90=α 7-4-2010.pdf 2102 لسنة 94-78 ،لثالثا العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة 87 تولد الغبار المتساقط في المنطقة الصناعية في مدينة فيالعوامل المؤثرة النجف األشرف م.د. حسين عبد المطلب علي خان كلية الهندسة -جامعة الكوفة الموجز مفن وذلف يهدف هذا البحث إلى دراسة العوامل المناخية وعالقتها بتكّون الغبار في مدينة النجفف المناخيفة تل العوامل مع النشاطات البشرية، كما بّين البحث أن أهف العوامفل خالل معرفة عالقة التفي أخففذت بناففر ارعتبففار هفي الحففرار والرطوبففة واحمطففار والريففاأ، رف تفف تحليففل ت ريرهففا بتجمففع كمففا بينففت الدراسففة وزيففاد تراكيففز الغبففار المتسففاقط وتحديففد ت ريراتفف البيقيففة فففي المنط ففة ال ففناعية كبر ت رير تل العوامل وأررها المه بزياد تراكيز الغبار المتسفاقط ففي منط فة الدراسفة، وأخيفرا إلى ف د ت إدراج ارستنتاجات والتو يات التي من ش نها ت ليل مخاطر هذه المشكلة : ملوثاااا الاااوالق القطاااا الصااناعيق الملوثاااا الدقااقيااةق العواماال المنا يااةق الكلماااا الدالااة طاا البشرية.النشا factors affecting dust formation in industrial zone at al-najaf al-ashraf city dr. hussein abdulmuttaleb ali khan lecturer at university of kufa/ eng. college abstract this paper aims at revealing the effect of the climatic characteristics on the dust formation in al-najaf city through defining the relationships between the climatic features and anthropogenic activities. the study revealed the climatic factors in the area of study as temperature, humidity ,rain ,and wind and analyzed their effects on dust concentration at industrial zone in order to determine the environmental impacts for the area of study. the analysis showed the great effect of climate and human activities on dust precipitating on the area of study. finally, the conclusions and recommendations which help the reducing of the risks of this important problem were presented. م.د. حسين عبد المطلب علي خان 87 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا keywords: air pollutants, industrial zone, particulate pollutants, climatic factors, anthropogenic activities. introduction المقدمة. 0 التلففوث احخفففرر، ويرجفففع ذلففف إلفففى ب شفففكاليعتبففر تلفففوث الهفففوار مفففن أخطففر أنفففوا التلفففوث م ارنفففة قي حيث أن الغالف الجوي المحيط بالكر احرضية والذي يبلغ سمك بضعة هوامحدودية المورد ال ة ن م ارنتهفا مفع حجف الكفر احرضفية، ومفن ناحيفعشفر كيلفومترات يمرفل بالكفاد قشفر رقي فة ر يمكف يسفتهل مفا اإلنسفانالوزن فان الموارد الماقية تبلغ أضعاف الهوار، أما من ناحية ارسفتهال ففان كيلوررامفات مفن المفار وف فط 3كيلفو رفرا مفن الهفوار يوميفا ففي حفين ر يسفتهل سفور 51معدل مكفن لهفا كيلو ررا واحد من الطعفا يوميفا، وعليف ففان الهفوار هفو ّسفر وجفود الكاقنفات الحيفة ور ي ( 2101حوقه وآ رونق ارستغنار عن ب ي شكل من احشكال ) الع فففور الوسفففطى، فالفففدخان إلفففىلففف يكفففن تلفففوث الهفففوار افففاهر حديرفففة ع فففرية بفففل ترجفففع جفففذوره عديففففد كففففان يعتبففففر مشففففكلة ح ي يففففة فففففي وقتهففففا وإلرففففرا الفحفففف قاحتففففراالمنبعففففث والنففففات مففففن (2117masters and ela,.) وث الهففوار النففات مففن نشففاطات اإلنسففان مففرتبط وعليفف فففان تلفف combustionال فرن احخيفر ولفذات السفبال تارشتففعال إلفىباكتشاف النار لتستمر هذه الخطفور process) ت)(2111nathanson,)، إلىملوث واحد أو أكرر إطالقا يت معند :يتلوث الهوار أو ضففرر لسنسففان أو الحيففوان أو بحيففث تتغيففر خ اق ف مففا ينففت عففن ذلف أذر الغفالف الجففوي الغففالف الجففوي الففذي تاهففر فيفف مففواد رريبففة بتراكيففز أعلففى مففن :أو (duggal, 2008)النبففات ربففر الحففدود الطبيعيففة والم بولففة بحيففث تكففون ذات تفف ريرات سففلبية علففى عنا ففر البيقففة الحيففة أو (kiely, 1997)الحية ن عشفر رورتهفا ال فناعية وهفي إحفالل الميكنفة بفدر شهدت بلدان أوروبا الغربية خالل ال فرن الرفام عفففن العمفففل اليفففدوي كمفففا أنهفففا نهضفففة علميفففة شفففاملة تنوعفففت فيهفففا احبحفففاث لتففف دي إلفففى اختراعفففات واكتشافات كانت السفبال المباشفر ففي قيفا الرفور ال فناعية والتفي كفان لهفا احرفر المباشفر والكبيفر وعنفدما ففي أوربفا وخارجهفا رففي ال فرن التاسفع عشف في الحيا ارقت ادية وارجتماعية والسياسية أمفادخلت ال ناعة ع ر السرعة واآللية زاد تعر العمل لألخطار واحمرا ، وهفذه احمفرا مباشفففر هفففن طريفففق التعفففر للمفففواد احوليفففة لل فففناعة أو ريفففر مباشفففر نتيجفففة لتلفففوث بيقفففة العمفففل (2100أبو العالق المحيطة ) ال ففناعية قففدمت خدمففة كبيففر لسنسففانية، ولكنهففا خّلفففت مشففاكل عديففد ، ولعففل ر ينكففر بفف ن الرففور والففذي خّ فف environmental pollutionواحففد مففن أهفف تلفف المشففاكل هففو التلففوث البيقففي ورن البيقيون ب ن سيشكل خطرا ح ي يا علفى الحيفا وبالتفالي سفيهدد الوجفود علفى سفطب الكوكفال، تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 78 الت نيففات التففي مففن إلففىال ففناعية أ ففبب مففن الضففروري التو ففل التلففوث هففو مخلفففات النشففاطات ، وان عمليفففة اسفففتبدال الطففففرق avoid pollutionشففف نها ت ليلففف وأن أفضفففلها تجنففففال التلفففوث وان كفان احمفر سي فاحب واحد من الحلفول المهمفة ارعتيادية ب خرر تكون أقل تسببا في التلوث إعففاد تففدوير بعفف المخلفففات أو المففواد الناتجففة مففن تكلفففة اقت ففادية، هففذا باإلضففافة إلففى تفعيففل ( crawford, 1976)العمليات الت نيعية وخ و ا أنها ذات قيمة ليس من المع ول تركها ,cheremisinoff)ا فملفوث للهفوار سف 577ود فوجف (who)حددت منامة ال فحة العالميفة يزياقيففففة والكيمياقيففففة لتلفففف وهففففذا مففففا يزيففففد احمففففر تع يففففدا بسففففبال اخففففتالف الخ ففففاق الف (2002 الملورففات، ب ففور عامففة تعتبففر التدفقففة و أعمففال الطففبا همففا الفعاليتففان الرقيسففيتان علففى المسففتور رفففار احنسففجة مفففا يجعفففل العففالمي والتفففي ي ففدر عنهمفففا الفففدخان واحبخففر واللتفففان تتسففببان بتهفففي وا ارات فاإلشففار إلففى أن الفضفف الحاجففة الملحففة لسففحال تلفف الملورففات وب ففور سففريعة، وهنففا ربففد مففن ففي العفال (indoor air pollution)ليا فا داخففر تلورففد هفي احكرففا تهوية جيفرير الخاضعة لنا (spengler, et al., 2001) . مشكلة الدراسة2 والفففذي تسفففاه بعففف المهمفففة يعتبفففر قطفففا ال فففناعة واحفففد مفففن قطاعفففات مدينفففة النجفففف احشفففرف حية واقت فادية للمنط فة ال فناعية بار وملورات أخرر تسبال أضراراربإطالق ال ناعات في والمنففاطق المجففاور ، لففذا سففيركز هففذا البحففث علففى متابعففة ملورففات الهففوار الغباريففة فففي منط ففة حففي عدن ال ناعية بالمدينة air pollutants ملوثاا الاوال. 3 لمادية )الدقاقق ال لبة منهفا والسفاقلة( قسمين هما الدقاقق ا إلىمن الممكن ت سي ملورات الهوار تنفرها المعامل تحتوي على هذين النوعين من التي احدخنة أنوالغازات من هذا الت سي نالحا تالملورا particulate pollutantsالملوثاا الدقااقية أوال: أوف الترابيففة مففرال قففد تكففون م ففادرها طبيعيففة كالعوا فف التففياحتربففة بالملورففات الدقاق يففةي ففد ويطلفق علفى الفدقاقق الماديفة احبخفر مفن تكرفف ناعية كالدقاقق ال فلبة منهفا والسفاقلة الناتجفة العال ة في الهوار باريروسول م.د. حسين عبد المطلب علي خان 75 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا الهفوار فيعتمفد علفى كميفة من مشفاكل لتلفوث يسبب الرذاذ )اريروسول( الذيالمدر أو نوعية أما ت ففففاس الففففدقاقق وعمومففففا فففففان كيميففففاقي ومعففففدل سففففرعة ترسففففبها ال الففففدقاقق وحجمهففففا وتركيبهففففا هفففذه التيوأن الدقاقق (boubel et al., 2008))الميكرون هو جزر واحد بالمليون( µ بالميكرومتر ويكفون إذا تجمعفت مفع بعضفها، إرتب ى معل ة في الهوار ور تترسال µµاقل من حجموهاتكون الففدقاقق أمففاوضففباال حففام الكبريتيفف ونبالكففار اقق ودقففالففدقاقق عمليففات التعففدين هففذهم ففادر وقطفففرات احتربفففةوهفففي تشفففمل جزقيفففات µ 5888واقفففل مفففن µ 588مفففن أكرفففرالتفففي حجومهفففا وتشفمل µ 588والفى µ 5الفدقاقق التفي يتفراوأ حجمهفا بفين بينمفا فهي تترسال بسرعة المطر (0474 ققنبورفروحة و ) ور بطيقةتترسال ب لاريروسو ن مختلفة من المواد والتي تكوّ أنوا :(2101 حوقهق) وهذه تشمل :gaseous pollutants ثانيا: ملوثاا غازية كسففيد الكربفففون أو رففازات ريففر عضففوية مرفففل :رففاني أوكسففيد الكبريففت وأكاسفففيد النيتففروجين وأول-أ كسيد الكربون وكبريتيد الهيدروجينأو وراني واحمففففففففففالأربونات والكحففففففففففورت والكيتونففففففففففات الهيففففففففففدروك ( عضففففففففففوية مرففففففففففل:أبخر رففففففففففازات) -ال سترات(العضوية)اح industrial zone and air pollution . قطاا الصناعة وتلوث الاوال9 مسقولة عن الكرير من ملورات الهوار، من ال طاعات ال ال ناعةب ن قطا الدراساتبين ، والوقودالمستخدمة والمواد وتعتمد كميات وأنوا المركبات المنبعرة على أنوا ال ناعة، ، والتدابير المستخدمة في الحماية البيقيةالمعتمد ، والتكنولوجياالمستعمل إلىالعالمية للهوار، والجدول يشير مساهمة ال ناعة في إرنبعاراتيتبين 5الجدول ومن خالل الغالف الجوي، إلىت دير ارنبعارات من النشاط ال ناعي وكسيد أ( مليون طن من راني 3188ال ناعة تطلق ما ي ارال ) ب ن 0441طلبةقوقد ذكر ( مليون طن من راني أوكسيد 5288ّن الزراعة تطلق )وأ ،%( 18الكربون، وتمرل عالميا نسبة ) %، 58%، و18(، مليون طن ونسبتها على التوالي من )5818الكاربون، والن ل تطلق ) %( من ارنبعارات 78( طن وتمرل ) 77الكبريت ) دأوكسيتطل ال ناعة من ما أما%(، 51و (، مليون 3قطا الن ل فيطلق نحو ) أما( مليون طن، 2الزراعة يطلق )قطا العالمية في حين ال ناعة والزراعة الكبريت على التوالي لل طاعات الرالرة أوكسيدطن وبذل تكون نسال انبعاث ما يطل قطا ال ناعة من أن 5771اوي، بّين الحنكما و %( 3%، و2%، و78) هي والن ل ( مليون طن، في حين يطلق قطا 28( مليون طن، و قطا الزراعة، يطلق )23الجسيمات ) (2117حميدق )%( 53%، و31%، و08) هي ( مليون طن والنسال على التوالي8الن ل ) تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 72 :اإلنسان. أضرار التلوث الاوااي على 1 ففي كريفر مفن بلفدان عةقشفاالو معروففة ال من الاواهررات المختلفة ااهر تلوث الهوار بالملو تعتبر clinical) اإلكلينيكيةالدراسات أربتتول د ،ال ناعية الكبرر واحقالي خا ة في المدن و العال studies) خا فففة ففففي الن فففف الرفففاني مفففن ال فففرن اإلنسفففانالتفففي يعانيهفففا اإلمفففرا كريفففرا مفففن أن ال لففال والسففرطانات المختلفففة إمففرا وكففذل الجلففد والحساسففية ا أمففر العشففرين والتففي مففن بينهففا هو تلوث احساسيالجهاز التنفسي عموما سببها المباشر وم درها وأمرا الرقة أمرا وأيضا قففد تعفدت معففدرتها فففي كريفر مففن منففاطق قيحففدود التلفوث الهففوا نبففعلمنفا اذإهفوار الجففو خا ففة عفن ويعّبر بهايشعر العاديوبدا رجل الشار واإلزعاجطور حد الخ إلىالعال المختلفة وو لت الهففوار عالقففة وري ففة ومترابطففة لتلففوث ، كمففا وأن (2101حوقااهق ) شففعوره بخطففور مشففكلة التلففوث م ففادر المهمفة لتلففوث الب شفكال التلفوث احخففرر كتلفوث الميفاه بحيففث اعتبفر تلفوث الجففو هفو أحفد ( 2119الفضالق والغبار ففي ميفاه احمطفار بشفكل أساسفي )المياه وذل عن طريق ذوبان الغازات باإلضافة إلى احضرار المادية والمتمرلة بوجود عالقة خطية بين زياد احتربفة والغبفار ففي الهفوار ( 0474فروحة وقنبورق )وتكاليف يانة احبنية والممتلكات . أهمية الدراسة6 ار على البيقة وعنا رها وخ و فا لمفا يسفاه من مخاطر وأضر وبالنار لما يسبب تلوث الهوار بفف قطففا ال ففناعة فففي تكففوين وتفففاق هففذه المشففكلة تبلففورت فكففر البحففث والففذي سيتضففمن قيففاس ففي منط فة حفي عفدن 2887ولغايفة العفا 2888كميات الغبار المتسفاقط لعفد سفنوات مفن العفا المفف رر فففي تكففوين الغبففار وتزايففده ال ففناعي بمدينففة النجففف احشففرف وبالتففالي متابعففة أهفف العوامففل وجعفففل البحفففث خطفففو باتجفففاه البحفففث العلمفففي الفففذي يعنفففى بدراسفففة مشفففكلة تلفففوث الهفففوار ففففي مدينفففة النجف احشرف موقع الدراسة. 8 كفف جنففوال 518ت فع مدينففة النجففف احشففرف علففى حافففة الهضففبة الغربيفة مففن ال طففر وعلففى مسففافة شففمارو /31o59شففرقاو وعلففى داقففر عففر /44o19خففط طففول رففرال مدينففة بغففداد إذ ت ففع علففى ك (، أما من الجنوال 78يحدها من الشمال والشمال الشرقي مدينة كربالر التي تبعد عنها حوالي ) والغرال فيحدها منخف بحر النجف، ومن الشرق تحدها مدينة الكوفة التي أ بحت اآلن تت ل 0الشكل ك (55)سافة كانت تبعد عنها بم أنبها عمرانياو بعد م.د. حسين عبد المطلب علي خان 73 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا الظروف المنا ية الساادة. 7 تحليفل إلفىيعتبر فه الخ فاق المناخيفة مفن احمفور المهمفة عنفدما يكفون الهفدف هفو الو فول اآلرار الناجمة إلىعلمي ودقيق لدراسة ملورات الهوار وتفسير نمط انتشارها وبالتالي يت التو ل تففف رير كفففل ملفففوث ودرجفففة تفاعلففف مفففع تلففف الخ فففاق عفففن التعفففر لتلففف الملورفففات بعفففد معرففففة )الحرار والرياأ والرطوبة واحمطار( المناخية المهمة يمتففاز منففاي مدينففة النجففف عمومففا ب نفف شففب قاحففل ، ففيفها طويففل وجففاف وشففتا ها بففارد وربيعهففا هي : 2الجدول وكما مبين في معتدل وخوا هذا الجو وبففين ال ففيف والشففتار ، حيففث تتففراوأ درجففة الحففرار مففا ونهففارا لففيالففرق كبيففر بففين درجففات الحففرار أ 00.0 و 8.7بين وهففذا فففي شففهر تمففوز % 22انخفففا الرطوبففة فففي الجففو وخا ففة فففي ال ففيف حيففث تبلففغ حففوالي ال معففدرت التبخففر، وارتفففا الرطوبففة فففي ف ففل الشففتار لت ففل فففي شففهر كففانون يف دي إلففى زيففاد فففي %17.5احول معدومفففة ففففي أشففففهر و ففففي شففففهر ذار ملففف 51.7ر متفرقفففة وبمعففففدل يتفففراوأ مفففا بففففين سففف وط أمطفففا ت ال يف / 2.3تسود الرياأ الشمالية الغربية في معا أيا السنة أمفا معفدرت سفرعة الريفاأ فتتفراوأ بفين ث ذار / را خالل اشهر0.5في شهر تشرين احول و را . المنطقة الصناعية في مدينة النجف األشرف4 متباينة من حيث الحج والنو والمساحة، أنماطيمتاز هيكل مدينة النجف ال ناعي بكون ذو توزعت على تستخد إلررا ال ناعة والتخزينوهذا الهيكل هو عبار عن خمس مناطق على منط تين ناعيتين هما : حي (ديوانية –النجف )المحور احول يحتوي، مختلفةمحاور باإلضافةي يض معامل المواد اإلنشاقية، النسي ، ت نيع احرذية، المطابع، عدن ال ناعي الذ ال ناعي ويض عدد من معامل الحرفيينمعمل المنتجات المطاطية، أما احخرر فهي حي إلى ، الحداد ، النجار )أعمال طحن الحبوال وت نيع احعالف وريرها( ت نيع المواد الغذاقية ف د أ بحت المنط تان في لنمو العمراني الذي شهدتُ مدينة النجف ومعامل النسي ، وبسبال ا المجاور موقع تتوسط في عدد من اححيار السكنية متمرلة احولىعلى منط تين والذي يحوي (كربالر –النجف )الشمالي فهو الراني المحورأما ك ( عن المركز 5الجانال احيسر من المحور وبمسافة ) بالمنط ة ال ناعية الواقعة على والمنط ة الرانية الواقعة معمل احلبسة الجاهز ،هو وتستخد كمخازن، أما ال ناعة الوحيد فيها تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 70 وقد خ ت ،ك ( عن مركز المدينة µ1) وعلى مسافة من نفس المحور الجانال احيمنعلى وبع ال ناعات الغذاقية كورش لت ليب المركبات والمعدات الر يلة ال ناعي لت ليب الحيف د كان مالقماو لتوقيع مجمع ،الكوفة –بة لمحور النجف ما بالنسوأ 2شكل ك ( من مركز المدينة، 6ومنط ة التخزين الرقيسة على بعد ) المركبات والمعدات، precipitate dust . الغبار المتساقط01 الذي ي ع على في هذا البحث ت اختيار موقع حي عدن ال ناعي في مدينة النجف احشرف كون ل يتوسط اححيار السكنية )احن ار والمعلمين والحورار والمرنى( ديوانية-محور النجف يحتوي على أكبر تنو ناعي في المدينة وخ و ا ال ناعات اإلنشاقية المختلفة في وقياس 1002العا ولغاية 1002من العا ر احتساال معدرتها الشهريةومن ،تراكيز الغبار المتساقط جهاز جمع الغبار الت ليدي )ارسطوانة المعدنية(وباستخدا سيعنى هذا البحث أيضا بتحليل كميات الغبار المتساقط الم اسة ح ليا ومن ر دراسة أه وأكرر ت ريرا بتولد الغبار في هوار مدينة النجف احشرف وخ و ا في )البشرية والطبيعية( العوامل المنط ة ال ناعية . مناقشة النتااج00 2112الغبار المتساقط في العام -أ يتبين من خالل عر نتاق الغبار المتساقط في المنط ة ال ناعية بمدينة النجف احشرف للعا يلي ذل 2ر / 7µ 2شهري نيسان وحزيران وبمعدل شهري ب ن أعلى كمية كانت في 1002 إلى، والسبال في ذل يرجع (3الشكل ) 2ر / 0 70وبمعدل أيارما تجمع من ربار في شهر الربيع ليبلغ معدل درجة إلىوارنت ال من ف ل الشتار اررتفا النسبي في درجات الحرار أن مايس )أيار(وليرتفع في شهر ˚ 2 15في شهر نيسان ( 2جدول )كما مبين في الحرار هذا إن، ˚ 6 77 إلىثم يتواصل هذا االرتفاع ليصل في شهر حزيران ˚ 7 12 إلىلي ل اررتفا نهارا ي دي إلى ارتفا حرار سطب احر احمر الذي سينت عن تيارات هواقية احعلى، أما في الليل سوف تنخف إلىالغبار وبالتالي دفع الملورات إرار اعد تعمل على حرار سطب احر والهوار ال ريال من السطب وت دي التيارات درجات الحرار ومع ستنخف زياد تراكيز ملورات الهوار إلىركود الهوار المحمل بالملورات مما ي دي إلىالهواقية النازلة حيث يالحا زياد سرعة (2جدول ) ومن العوامل الطبيعية الم رر هو اتجاه الرياأ وسرعتها 0 7 /را وفي شهر حزيران 0 0 إلى /را وي ل في مايس 5 7 إلىالرياأ في شهر نيسان م.د. حسين عبد المطلب علي خان 71 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا الرياأ الساقد في مدينة النجف احشرف هي الشمالية الغربية وان ازدياد سرعتها أنولكون /را الغبار وبالتالي زياد تراكيز الغبار المتساقط إرار سببا رقيسيا في وارتفا حرارتها ستكون أن إلىا العوا ف الغبارية حيث ت كد البيانات المناخية في المدينة ومن العوامل المناخية أيض جدول ) أكرر شهر في السنة يشهد عوا ف ربارية هو شهر نيسان يلي شهر مايس ر حزيران أعلى حد إلىهذه احشهر الرالرة ، وعلي لوحا ارتفا كمية الغبار المتساقط في (3 د تركيففز الغبففار المتسففاقط فففي المدينففة وفففي منط ففة حففي عففدن أمففا العوامففل البشففرية المفف رر فففي زيففا ال ناعي هو النشاط ال ناعي، تتنو الفعاليات ال ناعية في المنط ة بين المطفابع وال فناعات اإلنشفففاقيةالغذاقيففة واإلنشففاقية، وأن أكرففر هففذه ال ففناعات تلويرفففا للهففوار بالغبففار هففي ال ففناعات والزجفففاج والفففبالط تواإلسفففمنالطفففابوق بإنتفففاجالتفففي ي فففو وتشفففمل هفففذه ال فففناعات ال طفففا الفففذي وريرهفففا ، تختلفففف هفففذه واححجفففاروالكاشفففي والموزاييففف والنفففور والجففف والبلفففو والرمفففل والح فففى اإلنتاجيففةال فناعات حسففال المففواد احوليففة المسففتخدمة بالت فنيع أورت وخ و ففية ومراحففل الففدور العلايق ) ن حيث موقفع الففر ال فناعي ففي عمليفة البنفار رابعفاترانيات ونو الماد المنتجة رالرات وم ففففرو هفففذه ال فففناعة تشفففتر جميعهفففا ففففي أن وبفففالرر مفففن تعفففدد هفففذه ارختالففففات نجفففد (2111 اآلرفار البيقيفة باإلضفافة إلفى تح يق هدف واحد وهو استعمال منتجاتها النهاقية في عمليات البنفار معمففل 07معمففل، 15لكاشففي والشففتايكر فففي مدينففة النجففف يبلففغ عففدد معامففل الهففذه ال ففناعات معمفففل واقعفففة ففففي حفففي الحفففرفيين 52منهفففا واقعفففة ففففي حفففي عفففدن )موقفففع محطفففة جمفففع الغبفففار( و بالمدينة، ساهمت بتكوين الغبار المتسفاقط ففي موقفع الجمفع مفن جفرار ال ناعي في نفس المحور قة وريرها وأن زيفاد تراكيفز الغبفار ففي شفهر والن ل والتعب عمليات الطحن والتكسير للمواد احولية بينمفا اإلنشفاقيةبداية الزخ حيث داقما ما يشهد ف ل الشتار ركفودا ففي احعمفال إلىنيسان يعود المختلفففة مففا ينففت اإلنشففاقيةيشففهد ف ففل الربيففع تحركففا فعليففا يففنج عنفف ازديففاد الطلففال علففى المففواد عن زياد الملورات الدقاق ية معامل اسمنت الكوفة )الواقع في الملورة للهوار بالغبار هي شاطات ال ناعية احخررومن الن قضار الكوفة( وشركة الررمستون الواقعة في ح و الخورنق جنوال محافاة النجف ، على مناذر أيضا، -طريق نجف ف مناذر ، ومعمل الطابوق الجيري الواقع على طريق النجف كربالر -الواقعة معامل على محور النجف ق والج معامل الطابو إلى باإلضافة الملورة لهوار المدينة نتيجة لما يف د من أيضا من ال ناعات المدينةفي ارسمنت ناعة تعتبر ، كالغبار المتطاير من المواد وتطرأ إلى الهوار على شكل ربار مواد أنار العمليات اإلنتاجية ال من قس الطواحين التي تن ل ل بواسطة الحزا الناقل احولية المجمعة على شكل أكوا بال ر الرياأ، والغبار النات عن قس الطحن وكذل الغبار النات عن قس و وهي معرضة للتعرية تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 71 ونارا لكون أن الرياأ الساقد في المدينة هي ، التعبقة الذي يسه ب كبر جزر من الغبار المتطاير من مجمع الرياأ الهابة على %70 ا في شهر نيسان هي وخ و والشمالية الشمالية الغربية % µ6في نفس الشهر ما نسبت والجنوبية بينما تشكل الرياأ الجنوبية الشرقية( 3جدول ) المدينة يزداد من خالل تركيز الغبار المتساقط إضافياأي باتجاه موقع جمع الغبار لي بب هنا عامال ب ن كمية الغبار المتساقط في شهر تموز 7بين الشكل دفي هذا الشهر، على العكس من ذل ف رن الرياأ الشمالية الغربية والشمالية في شهر تموز لوذ 1ر / µ0 25كانت أقل ما يمكن نسبتها ذات الشهر فيفي حين كانت الرياأ الجنوبية الشرقية والجنوبية 7 60نسبتها عالية جدا µ 0 ذات ، )احمر الغبار بعيدا وبعكس اتجاه موقع جمع الغباراحمر الذي يجعل الرياأ تن ل ينطبق على ما يتكون من ربار متساقط نات من شركة الررمستون ومعمل الطابوق الجيري حيث ي عان في ذات المحور الجنوبي لمدينة النجف احشرف( 2118الغبار المتساقط في العام -ب 77.44كانت في شهر ذار 2002ط في العا ب ن أعلى كمية ربار متساق 4الشكل يبين 89.62في حين كانت أقل كمية متجمعة في شهر ال 2ر / 74.02يلي شهر نيسان 2ر / ( حيث يالحا زياد 2جدول يعتبر اتجاه الرياأ وسرعتها من العوامل الطبيعية الم رر ) 2ر / ، /را 2 1را وي ل في ال إلى / 5 7 /را ر شهر نيسان µ 0سرعة الرياأ في شهر ذار إرار الغبار وبالتالي زياد هذا اررتفا في معدرت سرعة الرياأ في منط ة الدراسة أدر إلى إن ف د أوضحت البيانات ب ن أعلى معدل للعوا ف العوا ف الغبارية أماتراكيز الغبار المتساقط (، وعلي لوحا 3جدول )على التوالي µ 7و 2 0الغبارية كان في شهري ذار ونيسان وبمعدل بينما كان معدل العوا ف الغبارية ارتفا كمية الغبار المتساقط في هذه احشهر إلى أعلى حد احمر الذي نت عن انخفا معدرت الغبار المتساقط 0µ 0منخفضا في شهر ال ب ن اتجاه (3جدول )يةأما فيما يتعلق بالنشاطات البشرية ال ناعية ف د بينت البيانات المناخ لشهر ذار من مجمو الرياأ الهابة على المدينة 26.6الرياأ الشمالية الغربية والشمالية كان فان الرياأ الشمالية لشهر ال ، أما بالنسبةللرياأ الجنوبية الشرقية والجنوبية 89.1بينما المعدل من مجمو 8.1ية الشرقية والجنوبية في حين كانت الرياأ الجنوب 16.4الغربية والشمالية كانت لشهر ذار لمتساقطا، احمر الذي نت عن ازدياد معدرت الغبار تهال على المدينة التيالرياأ رن الرياأ ستن ل الغبار وباقي الملورات باتجاه معاكس كميات في شهر الاونيسان وانخف لموقع جمع الغبار م.د. حسين عبد المطلب علي خان 78 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا 2119ر المتساقط في العام الغبا -ج 71.24( كانت في شهر نيسان 5الشكل ) تبين ب ن أعلى كمية للغبار المتساقط 2006في العا كانون احول ، بينما كانت أقل كمية في شهر 2ر / 46.06شهر تشرين احول يلي 2ر / 2ر / 87.9 على معدل تلعال عوامل المناي كالحرار والرطوبة النسبية وسرعة الرياأ دورا كبيرا في تكوين أ ، وأن زياد تركيز 2004للغبار المتساقط في شهر نيسان كما مّر في ف ر الغبار المتساقط للعا الغبار في شهر تشرين احول يخضع لنفس احسباال خا ة وأن درجة الحرار والرطوبة النسبية شهر ريبة مما في قمعدرت وهي )على التوالي( 46.4و ˚ 29.1هي في شهر تشرين احول 78.1ة النسبية وان الرطوب ˚ 21.2نيسان البالغة أما أقل كمية للغبار المتساقط فكانت في شهر كانون احول حيث الرطوبة النسبية العالية والبالغة كمية احمطار بحيث يعمل بخار المار على تن ية الهوار من عوالق كرير ، باإلضافة إلى 92.8 رها تعمل على تن ية احجوار بعد أن تزيد وزن الدقاقق مساعد في التي بدو مل 6.1المتساقطة ترسيبها بفعل الجاذبية احرضية احمر الذي ينت عن قلة تركيز الغبار المتساقط في هذا الشهر وفيما يخ العوامل البشرية فان ازدياد معدرت الغبار المتساقط لشهر نيسان متواف ة مع ما باسترنار ما يحدث في شهر كانون احول حيث أن معدل الرياأ 2004جار في ف ر العا وبالتالي فان هذه احخير 87.2والجنوبية الشرقية والجنوبية 27.2الشمالية الغربية والشمالية ار المتجمع في شهر تموز بموقع جمع وبكمية أكرر من الغ إلىست و بن ل جزر من الغبار 2004للعا الشكل وكما في 2006-2004المشتركة بين كميات الغبار المتساقط للسنوات ولغر الم ارنة في شهر نيسان ر في شهر ذار في عا 2006يالحا ب ن أعلى كمية ربار كانت في العا 6 ت انابين بي اإلح اقيمعامل اررتباط كان، وقد 2004وان أقلها كانت في شهر تموز 2002 ، في (0.58) 2004والعا 2002، وبين بيانات العا (52 0) 2002والعا 2006 االع ، أي أن أعلى ارتباط كان ما بين نتاق (0.39) 2006والعا 2004حين بين بيانات العا وهذا يتضب من ال ياسات الح لية إذ أن أعلى كمية ربار متساقط كانت 2006 و 2002العا لذات العامين، على العكس مع لنتاق في شهر الرال اات إلى باإلضافة مت اربة بين العامين، 2004كميات الغبار المتساقط مع ما تجمع في العا conclusions . االستنتاجاا02 أررت العوامل المناخية بشكل كبير على كميات الغبار المتساقط في منط ة الدراسة -أ تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 77 الغبار المتساقط في المنط ة كان للعوامل البشرية دورا هاما في الت رير على تراكيز -ال تفاعلت الخ اق المناخية والعوامل البشرية في تحديد كميات الغبار المتساقط في موقع -ج الدراسة و 2004بينت الدراسة ب ن أعلى كمية للغبار المتساقط كانت في شهر نيسان للعامين -د 2004، وأقل كمية كانت في شهر تموز 2006و من خالل ما بين معامل اررتباط 2006و 2002لغبار المتساقط للعامين ت ارال نتاق ا -هف اإلح اقي للبيانات recommendations . التوصياا33 توسيع قاعد الدراسة والتحليل الخا بالغبار والملورات احخرر في باقي مناطق وقطاعات -أ المدينة احخرر قيع المناطق ال ناعية في المدينة تجنبا لحارت اعتماد مبدأ التخطيط البيقي ال حيب عند تو -ال التلوث التي تنت عن عشواقية اختيار الفضارات في المدينة لمعرفة م ادر التلوث وتشخي زياد عدد محطات جمع الغبار في المدينة-ج أنواعها والحد من مخاطرها المصادر -boubel, richard w., fox, donald l., turner, d. bruce, stern, arthur c., vallero, daniel a., "fundamentals of air pollution" fourth edition, 2008. cheremisinoff, nicholas p., "handbook of air pollution prevention and control", 2002. crawford, martin, "air pollution control theory" , 1976. duggal, k.n., "elements of environmental engineering", s. chand&company ltd. 2008. -kiely, g., "environmental engineering", mcgraw-hill, international (uk) limited, 1997. masters, gilbert, m., and ela, wendell p. "introduction to environmental engineering and science",3 rd edition prentice hall, inc. 2008. م.د. حسين عبد المطلب علي خان 77 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا -nathanson, j. a.," basic environmental technology", prentic-hall, inc.,2000. spengler, j. d., samet, j. n. ,mccarthy, j. f., "indoor air quality, handbook" , 2001. 2855ة المهنية في ت مين بيقة العملت ،أبو العال، مجدي إبراهي ، تالسالمة وال ح العلي، كفاية عبداهلل، ت ال ناعات اإلنشاقية في محافاة الب ر واقعها و فاقها المست بليةت ، وهي جزر من متطلبات درجة الدكتوراه فلسفة في لب ر أطروحة دكتوراه، كلية اآلداال / جامعة ا 2881الجغرافيا، ن والبيقة بين الحضار الغربيفة واإلسفال ت ، دراسفة تحليليفة عفن العفراق الفضل، يوسف، ت اإلنسا 2880كنموذج للدول النامية، .2888الهيأة العامة للمساحة ,الحدود اإلدارية , بغداد حالففة الدراسفة تلفوث هفوار مدينفة بغفداد بسففبال -حميفد، محمفد علفي، تاقت فاديات التلفوث البيقفي وحة دكتوراه رير منشور ، المعهد العالي للتخطيط الحضري ، واإلقليمي أطر عواد المركباتت ، 2887، جامعة بغداد ، حوقفف ، فتحففي إسففماعيل، وبيففومي، سففامية محمففد، وال اضففي، شففريف محمففد، ت تلففوث البيقففة إلففى 2858أين؟ ت 5777فروحة، بري ميخاقيل، وقنبور، ف اد إبراهي ، ت تلوث البيقةت، زارة البلدددياو واغشغدد اد, مديريددة التلعدديا العدد مرامي, التصددميم اغاااددي لمدي ددة ال دد و اغشرف. وزارة ال قل والمواصالو ,الهيأة العامة لألمواء ال وية ,قسم الم اخ , بياماو غير م شورة. تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 78 نسال انبعاث الملورات من النشاط ال ناعي 0جدول (2887 )حميد، 5770في العال لغاية ال سبة المئوية لالمبعاثاو % كمية االمبعاثاو )مليون طن( أمواع الغازاو الم بعثة 18 3188 ثامي أوكسيد الكاربون 20 70 الميثان 53 8.2 أوكسيد ال تروجين 28 8 االموميا 78 77 أوكسيد الكبريت 00 38 أوكسيد ال تريك 08 23 ال سيماو العالقة 18 21 الهيدروكاربوماو cfc 5.2 588 الكلورفور والكربوماو (2887-2888قيم الع اصر الم اخية في مدي ة ال ) 2جدول معدد الشهر السعوع الفعلي درجة الحرارة العظمى درجة الحرارة الصغرى المعدد ºم ْ الرطوبة ال سبية % كمياو التساقا ملم ارعة الرياح ثا\م 3,8 2,8 13,3 50,7 8,7 25,7 1,0 2كامون 3,0 3,1 11,7 51,7 58,0 23,2 8,3 شباط 0,5 51,7 18,8 25,0 50,1 27,7 7 اذار 3,1 53,8 05,1 21,7 57,1 33,5 7,1 ميسان 0.8 0,8 35,3 27,3 22,8 31,8 7,1 )ايار(مايس 3,0 ---20,2 33,1 21,8 05,3 55,1 حزيران 0,1 ---22,8 31,1 27,7 00,0 55,1 تموز 2,7 ----23,2 31,8 27,5 00,8 55 اب 2,8 ----27,2 32,1 20,1 08,1 58,5 ايلود 2,3 1,8 37,8 21,1 57,0 33,1 7,1 5تشرين 2,0 1,5 11,3 57,3 52,2 20,1 8,3 2تشرين 2,1 7,1 17,5 51,0 7,1 25.0 1 5كامون المصدر :دائرة اغمواء ال وية في محافظة ال ,بياماو غير م شورة م.د. حسين عبد المطلب علي خان 75 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا مسبة معدد تكرار ات اه الرياح ومعدد عدد أيام 3 جدول حدوث العواص الترابية في محافظة ال معدد تكرار ات اه الرياح للمدة الشهر 5778 2887 عدد العواص الغبارية شمالية شرقية وشرقية ج وبية شرقية وج وبية ج وبية غربية وغربية شمالية غربية وشمالية سكونال 8.3 21,7 21.5 25.1 51 55.1 كامون الثامي 8.1 23,5 28.1 57.3 58 53.5 شباط 8.7 25,1 27.7 57.2 51.1 52.7 آذار 5.3 25,1 38 57 51 50.1 ميسان 5 57,0 08 51.7 58.1 53.2 مايس 8.0 58,1 11.3 25.5 2.3 3.8 حزيران 8.5 52,0 18.3 20.7 5 5.1 تموز 8.85 50,1 17.3 22.5 5.1 2.1 آب 8.87 20,8 15 51 3.1 1.7 أيلود 8.5 28,8 31.1 51.7 7.7 55.5 تشرين اغود 8.2 28,7 32.5 57.5 55 58.7 تشرين الثامي 8.5 28,7 20.7 25.8 50.7 58.7 كامون اغود 8.0 25,7 37.3 57.8 7.7 7.2 المعدد الس وي 8,2 18.3 21.2 52.1 55.8 ال سبة المئوية المصدر: محعة اغمواء ال وية في محافظة ال موقع مدينة النجف احشرف الجغرافي 0شكل (2888)الهيأة العامة للمساحة ,الحدود اإلدارية , بغداد تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 72 مدينة حي عدن ال ناعي في استعمارت احر ال ناعية مع موقع جمع الغبار في 2شكل )خريطة الت مي احساس لمدينة النجف( ف احشرفالنج موقع جمع الغبار قط في المتسا منطقة حي عدن الصناعي م.د. حسين عبد المطلب علي خان 73 2102لسنة 49-87لخامس، العدد الثالث، مجلة القادسيه للعلوم الهندسيه، المجلد ا 0 5 10 15 20 25 30 35 40 45 50 2 /م غم ، ط اق س مت ال ر با لغ ا كانون الثاني تشرينأيلولآبتموزحزيرانايارنيساناذارشباط األول تشرين الثاني كانون األول 2007 كمية الغبار المتساقا )الغرام/م 3شكل 2 بمدي ة ال اغشرف ( في م عقة حي عدن الص اعي .2888للعام 0 5 10 15 20 25 30 35 40 45 50 2 /م غم ، ط اق س مت ال ر با لغ ا كانون الثاني تشرينأيلولآبتموزحزيرانايارنيساناذارشباط األول تشرين الثاني كانون األول 2008 كمية الغبار المتساقا )الغرام/م 9شكل 2 ( في م عقة حي عدن الص اعي .2887بمدي ة ال اغشرف للعام 0 5 10 15 20 25 30 35 40 45 50 2 /م غم ، ط اق س مت ال ر با لغ ا كانون الثاني تشرينأيلولآبتموزحزيرانايارنيساناذارشباط األول تشرين الثاني كانون األول 2009 ة الغبار المتساقا )الغرام/مكمي 1شكل 2 ( في م عقة حي عدن الص اعي .2887بمدي ة ال اغشرف للعام تولد الغبار المتساقط في المنطقة الصناعية في مدينة النجف األشرف فيالعوامل المؤثرة 2102لسنة 49-87لهندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ا 70 0 5 10 15 20 25 30 35 40 45 50 2 /م غم ، ط اق س مت ال ر با لغ ا كانون الثاني تشرينأيلولآبتموزحزيرانايارنيساناذارشباط األول تشرين الثاني كانون األول 2007 2008 2009 كمية الغبار المتساقا )الغرام/م 6شكل 2 عدن الص اعي( في م عقة حي (.2887 -2888بمدي ة ال اغشرف لألعوام) 6-2-2011.pdf 68 four varieties of sodium feldspar substitutes have been prepared. different percentages of kaolin, silica and sodium salts are milled, mixed and submitted to heat treatment. the reacted powders are then grinded and tested by x-ray diffraction. the results show the existence of feldspar phase. the densities were measured and show close agreement to the reported values. the final result is establishing a technological root for the synthesis of feldspar substitute utilizing local materials. feldspar substitute, sodium feldspar, solid reaction, local materials, technological root. . ج– .. . ... : . . . . . broad ranges of triaxial ceramic compositions are used in ceramic and glass industries. these are including white wares, insulators, pots, filters, fillers and every aspect of glass applications. these products are essentially contains kaolin, quartz and feldspar. ( ) the kaolin is a source of alumina and silica and it is usually of fine particle size that brings plasticity necessary to assist forming. feldspar acts as a flux, forming a viscous liquid at firing temperature that aids vitrification. thus, the feldspar is vital to successful sintering, i.e. forming the final ceramic body. the quartz is mainly an inexpensive filler material which remains un-reactive at low temperature of firing and forms a highly viscous liquid at higher temperatures. the main differences between the compositions are in relative amounts and kinds of feldspar and kaolin used. mullite (3al2o3.2sio2), -quartz and glass contribute major portion of porcelain microstructure in triaxial based kaolin–quartz–feldspar system. ( ). 69 in addition to the major role in sintering porcelains, the feldspar is also very important low temperature component in glass receipts. the feldspar helps forming balanced amounts of alumina, silica and fluxing alkalizes that improves the mechanical properties of the produced glass. the feldspar itself is not naturally stoichiometric for the alumino-silicates and alkalizes. it is naturally occurring as mineral mines or volcanic rocks. it is often exists together with the quartz or, occasionally, with mica and some silicates. feldspar precipitates that are found in desert areas are usually less abundant to be of economical amounts. ( ) the well-known types of feldspars are potassium, sodium, calcium, barium, lithium feldspars and else. the ratio of the alkaline oxides to the alumina and silica content was 6:1:1; and it was 2:1:1 for the alkaline earths oxides. illustrates some physical and chemical properties for a number of feldspars. the melting point was in the range of (1118-1532°c), the densities falls in the range of (2.53-3.37g/cm3) and (6-6.5moh) for hardness. ( ) the alkalize in the feldspar decreases its melting point, e.g. when the porcelain (kaolinfeldspar-silica) is subjected to high temperature, the feldspar converts to viscous vitreous state and then melts while the other components stays in the solid state. the feldspar melt assists wetting of solid particles which then agglomerates by surface tension. on a second stage, the melt diffuse in remained body pores and enhance partial melting during the heat treatment. the feldspar of finer particle size accelerates this process. ( ) the feldspars are usually used in fine ceramics with weight ratio of 10-50%. the potassium feldspar is distinguished for its relatively low melting point (1150°c) where the lucite phase (k2o.al2o3.4sio2) starts evolving with extra silica. the lucite phase has high viscosity (10 dpoise) at temperature of 1400°c, where, the sodium feldspar has lower melting point (1118°c) and has low viscosity (10-1 dpoise) at 1425°c. therefore, the sodium feldspar proves also useful in glazing and glass technology ( ). the employment of feldspar in the composition of ceramics has obvious effect on plasticity, transparency, thermal and mechanical properties. in addition, the feldspar has noticeable benefit in the production of glass due to its role in melting of silica, thermal expansion, chemical resistance, scratch resistance and compressive strength of the final product. ( ) the feldspar is sometimes substituted by (nepheline syenite) in some countries like america and canada. the nepheline syenite has chemical composition compared with that of feldspars and it can be found within the volcanic rocks almost free of extra silica. the density of the nepheline syenite is around 2.54 g/cm3 and its hardness is 6 moh. ( ) the feldspar plays a very important role in ceramic and glass industry. substitutes of feldspars can be utilized as a replacement. finally, due to the lack of feldspars and its substitutes in iraq and the imported materials is usually expensive, the porcelain and glass industry need alternatives. the goal of this project is to establish a technological root for the synthesis of feldspar substitute utilizing materials locally available. iraqi duekhla kaolin and iraqi urdhuma flint (silica) was brought from the department of geological mining of the ministry of industry, baghdad. the chemical analysis was performed at the same department for both the kaolin and the flint and shown in . commercial grade sodium carbonate (purity 98%) was utilized. the remaining (impurity) parts of the carbonate were mainly kaolin and silica. pure alumina (99.5% purity) is also utilized. the impurities were also kaolin and silica. the powders were milled and sieved via laboratory milling and sieving system. powder below 75 m was used for the subsequent steps. different weight percentages for powder recipes is experimented to prepare the feldspars. each recipe was mixed for 6hrs by means of a planetary mill and porcelain balls to assure homogeneous mix. the weight percentages for the best results are shown as four recipes in . after mixing, steel dies and hydraulic press was used to prepare the powder compacts. single action die compaction is utilized. the compacting of powder mixes is performed to increase 70 the contact area of mix components and accordingly, to enhance solid-solid reaction. the compacting pressure was 7mpa and the resulting dimensions of the cylindrical compacts were 3cm diameter and 2cm height. numerous heat treatment experiments were performed to achieve the best heat treatment schedule. the criterion is to obtain complete solid-solid reaction. straus (germany) muffle type furnace has been used for heat treatment. the final heat treatment schedule is shown in . x-ray diffraction of the reacted powders is utilized to evaluate the results. cu-k radiation was used to obtain x-ray diffractograms on phillips diffraction system at al-raya company. astm diffraction data files, vol.7 dec1897) ( ) was employed to compare and to define the resultant phases. the densities are also evaluated by means of both the geometrical and archimedes methods. the reacted powders shown by by means of the heat treatment shown in is given the same code numbers and referred below as sample no.1, 2, 3 and 4. the sample no.1 has greenish color and a relatively low melting point compared with the other feldspars. this agrees with the literature when examining its x-ray diffractogram presented in . the diffractogram shown in illustrates that an obvious amount of silica does not reacted. the low melting temperature indicates the existence of the glassy phase na2sio3 which cannot be detected by x-ray diffraction and also explain the greenish color. the major part of the used alumina was replaced by the kaolin for the sample no.2. the xray diffractogram in shows that the amount of the free silica is reduced. the introduction of kaolin as a starting material and a source of alumina prove advantage. the sample color is now more bright or cream. the melting temperature is higher than the sample no.1, explicitly, 1150°c. thus, samples no.1 and 2 is very close to the pegmatite ore. the pegmatite is composed of silica and feldspar and usually found applications in porcelain industry when the iron oxide impurity does not exceed 0.5%. the pegmatite is also used in glass industry and the iron oxide impurity is accepted up to 2%. ( ) when the kaolin content is further increased at the expense of silica for the sample no.3, the x-ray diffractogram ( ) did not show evidence for the silica phase. this indicates that some sort of stoichiometry is achieved. thus, sample no.3 can be regarded as single phase sodium feldspar. on the other hand, the high background scatter displayed in the diffractogram may indicate deficient crystallinity. the poor crystallinity may encourage early disintegration when used as part of porcelain content. the early disintegration of the feldspar when firing the porcelain body may initiate the formation of the mechanically weak phase na2sio3. therefore, attempts are made to have better crystallinity by trying to improve the stoichiometry of the starting recipe. the improved recipe is attained and reflected as sample no.4. the x-ray diffractogram for that sample ( ) shows sharper peaks and enhanced intensities. the d-spacing values better fits the astm standard for the sodium feldspar. the high angle peaks are displayed clearly which is resembles other indication for good crystallinity for the synthesized sodium feldspar. it remains to state that the measured densities for the four types of the synthesized feldspar are 2.5-2.52g/cm3 which agrees with the reported density values for sodium feldspars. four types of sodium feldspar substitutes have been prepared which can find applications in glass and porcelain industry. the starting materials are mainly local raw materials. the first and second type has free silica and close to the pegmatite ore. the third type show no evidence of free silica and the forth shows better crystallinity. this give broad range of materials choices of the feldspars. 71 andreeva i. a., kovalenko v.i., naumov v.b., “sulfate-silicate liquid immiscibility: evidence from melt inclusions in minerals of carbonatites and related alkaline rocks”, 4th eurocarb workshop canary islands, spain, 16th-21st september 2003, page 25. bhattacharyy a., das s. and mitra n. “effect of titania on fired characteristics of triaxial porcelain” bull. mater. sci., vol. 28, no. 5, august 2005, pp. 445–452. britton j., “alaska resource data file, hughes quadrangle, alaska”, u.s. department of the interior, u.s. geological survey, 2003 dannert c., durschang b., raether f., becker f. “optimization of sintering processes for porcelain using in-situ measuring methods”, materials week 2000, munich, germany, symp. i3 process development, 2001, pp.1-6 gülsoy ö. y., can n. m. and bayraktar, i., “production of potassium feldspar concentrate from a low-grade pegmatitic ore in turkey”, mineral processing and extractive metallurgy, vol. 114 (2), p.p. 80-86, jun 2005 mcclune w. f., “astm powder diffraction file”, international center for diffraction data, published by the jcpds, u.s.a., vol.7 1987. rasmussen s. and cutler i. “sintering of feldspars” j. amer. ceram. soc. vol. 71 no. 5-10 1971. budnikov p. p “the technology of ceramic and refractories” the m.i.t press. 1982 saiintawong k., jiemsirilers s., tada, m., jinawath s., “forming porcelain insulators” ceram. indus. mag., may. 2008, pp.1-6 sikalidis c., kassolifeumaraki a. and filippidis a. “feldspars from the parents pegmatite veins for the ceramic and glass industries” interceram. vol. 46 no. 4 1977. singer f. and singer s. “industrial ceramic” london chapman and hall.1984 : physical and chemical properties for some feldspars (sikalidis , 1977) minerals formula densityg/cm3 hardness moh melting point °c color crystalline form potash feldspar k2o.al2o3. 6sio2 2.54 6 1150 white monoclinic soda feldspar na2o.al2o3 .6sio2 2.63 6-6.5 1118 grey triclinic lime feldspar cao.al2o3. 6sio2 2.7-2.76 6-6.5 1552 white triclinic barium feldspar bao.al2o3. 6sio2 3.37 >6 ------triclinic lithium feldspar li2o.al2o3. 6sio2 2.64 5.5-6 ---white monoclinic 72 : chemical analysis of duekhla kaolin oxide weight % oxide weight % sio2 47.26 cao 0.15 al 2o3 34. 84 mgo 0.38 fe 2o3 1.3 2 nao2 0.25 tio2 1.4 k2o 0.61 loss of ignition l.o.i. 12.91 : chemical analysis of urdhuma flint oxide weight % oxide weight % sio2 98.4 cao o.3 al 2o3 0.4 mgo 0.3 fe 2o3 0.0 5 l.o.i. 0.55 : wt% for the powders included to prepare the feldspars code sodiumcarbonate kaolin silica alumina 1 20.2 ---19.4 60.4 2 20.2 34.4 41.4 4.0 3 20.2 48.8 28.8 ---4 20.2 51.3 26.3 ---: heat treatment schedule used for preparation of feldspars heating rate 2°c/min max. temperature 1100°c firing time 2hrs cooling rate 5°c/min 73 : x-ray diffractograms for sample no.1, the d-spacing value of the mean peaks for the sodium feldspar are shown. the peaks that indicates the silica (quartz) phase is marked, as well. : x-ray diffractogram for sample no.2. the peak areas of the silica (quartz) are reduced. 74 : x-ray diffractogram for sample no.3. the quartz phase begins to disappear, but the background at low angles is high. : x-ray diffractogram for sample no.4. the background is reduced indicating higher crystallinity. 6-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۳ numerical analysis of vapor flow in a horizontal cylinderical heat pipe mr. selah m. salih mr. qahtan a. abed mr. dhafeer m. al-shamkhi automobile tech. eng. dept. technical college najaf automobile tech. eng. dept. technical college najaf automobile tech. eng. dept. technical college najaf abstract the steady two-dimensional flow of a horizontal heat pipe in vapor region is investigated numerically. for study of heat transfer and fluid flow behaviors of the heat pipe, the governing equations in vapor region have been solved using a finite difference method. the numerical results of heat transfer and fluid flow are presented for reynolds numbers ranging of (re =4, 10), the prandtl number taken is (pr=0.00368), and the pipe dimension is taken to be (l/r =5). the results show that the stream function at the wall increases linearly in the evaporator, decreases linearly in the condenser and is steady in the adiabatic region because of uniform inflow and outflow boundary conditions. also, it can be seen that as the reynolds number increases, the pressure distributions shift up without considerable change in their shapes. the numerical analysis have shown that for the low and moderate reynolds number, the shear stress becomes zero at a point very close to the end of the condenser. for verification of current model, the results of stream function for a heat pipe have been compared with the previous study at the same boundary conditions and a good agreement has been noticed. keywords—vapor region; heat pipe; numerical study. . . .. : . . في ـي لا. ف (re =4, 10)،(pr=0.00368) ،( l/r =5) . ". ل.، al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳٤ ، "" . ،. nomenclature cp = heat capacity at constant pressure (kj/kg. k) hfg = latent heat of vaporization (kj/kg) k = thermal conductivity (w/m. k) l = length (m) p = pressure (n/m2) q = heat transfer (w) r = gas constant (kj/kg. k) rv = vapor radius (m) ro =outer radius of pipe (m) re = reynolds number pr = prandtl number t = temperature (k) v = radial vapor velocity (m/sec) u = axial velocity (m/sec) v = reference velocity (m/sec) x = axial coordinate (m) r = redial coordinate (m) greek symbols ѱ = stream function (m2/sec) ω = vorticity (sec-1) α = fluid thermal diffusivity (m2/sec) υ = kinematics viscosity (m2/sec) μ = dynamic viscosity (kg/m. sec) ρ = density (kg/m3) τ = shear stress (n/m2) θ = dimensionless temperature subscripts * = dimensionless term a =adiabatic c =condenser e = evaporator v = vapor int = interface o = outer sat = saturated introduction the heat pipe is a vapor-liquid phase-change device that transfers heat from a hot reservoir to a cold reservoir using capillary forces generated by a wick or porous material and a working fluid. heat pipes are the most effective passive method of transferring heat available today. heat pipes can transmit heat at high rates and have a very high thermal conductance. heat pipes have been applied to a wide variety of thermal processes and technologies. heats pipes have been applied in the cooling devices include generators, motors, nuclear, heat collection al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳٥ from exhaust gases, solar and geothermal energy. in general, heat pipes have advantages over many traditional heat-exchange devices, (doran, 1989). the vapor flow in heat pipes has been investigated by various authors, (rajashree and sankara, 1990), (chan and faghri, 1995), (zhu and vafai, 1999), and (kim et al, 2003) have published many techniques, theories, and experimental investigations of different heat pipe structures. they found the pressure and velocity distributions along the heat pipe depended on the value of radial reynolds numbers. (nouri-borujerdi and layeghi, 2004) analyzed the vapor flow in concentric annular heat pipe using simple algorithm and staggered grid scheme. they found the flow and heat for vapor heat pipe was affected by increasing of radial reynolds numbers. (yau, 2007) studied an 8-row thermosyphon-based heat pipe heat exchanger for tropical building hvac systems experimentally. this research was an investigation into how the sensible heat ratio (shr) of the 8-row hphe was influenced by each of three key parameters of the inlet air state, namely, dry-bulb temperature, and relative humidity and air velocity. (david et al., 2008) design and test of a pressure controlled heat pipe (pchp), testing showed that (pchp) was capable of maintaining a stable evaporator temperature within (0.1k) despite wide swings in heat load and heat sink temperature. in this paper a numerical model has been used for analysis of vapor flow in heat pipe operation. the steady state incompressible flow has been solved in cylindrical coordinates in vapor region. the governing equations have been solved using finite difference with collocated grid scheme. the objective of this paper is study the heat transfer and fluid flow behavior of a conventional heat pipe operation. mathematical model and governing equations figure 1 shows the simplified model and the coordinate system of the constant conductance heat pipe (cchp) used in the present study. the heat pipe configuration can be divided into three radial regions, namely, vapor space, wick region and wall region .the working fluid is saturated with wick in liquid phase. the power applied to the heater in evaporator causes the liquid in the wick to vaporize. the vapor flows to the condenser section and releases the heat as it condenses. the released heat is rejected through the wall to the ambient. the condensed working fluid in the wick returns to heater section by the capillary force of the wick structure. to analysis the behavior of flow of fluid and heat through the heat pipe by using continuity, momentum and energy equations as flows. heat applied to evaporator section by an external source is conducted through the pipe wall and wick structure, where it vaporizes the working fluid. the resulting vapor pressure drives the vapor through the adiabatic section to the condenser, where the vapor condenses and releasing its latent heat of vaporization to the provided heat sink. the capillary pressure created by the wick structure, pumps the condensed fluid back to the evaporator. therefore, the heat pipe can continuously transport the latent heat of vaporization from the evaporator to the condenser sections. this process will continue as long as there is sufficient capillary pressure to drive the condensate back to the evaporator. at the vapor–wick interface, the temperature is assumed to be saturated, corresponding to interface pressure during heat pipe operation. axial conduction along the wall and wick is assumed negligible. the steady state two–dimensional incompressible laminar flow with constant viscosity in cylindrical (r-x) coordinate, and no heat generation. the governing equations in vapor region are continuity, navier-stokes and energy equations, (rajashree and sankara, 1990), are given as follows: 0 )(1 r rv rx u (1) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳٦ 2 21 2 2 r u r u rx u x p r u v x u u (2) 22 21 2 2 r v r v r v rx v r p r v v x v u (3) 2 21 2 2 r t r t rx t k r t v x t ucp (4) the radial velocities at liquid-vapor interface, (borujerdi, 2004), as following: fgvco c c a fgveo e e hlr q v v hlr q v 2 0 2 (5) the temperature at the vapor-liquid interface of the evaporator and condenser is calculated approximately using clausius-clapeyron equation, (borujerdi, 2004): )( )( ln 1 1 ),(int sattsatp vtvp fgh r satt vrxtt (6) the boundary conditions for vapor region are as following, (rajashree and sankara, 1990). at both pipe ends are: 00 x t uv (7) at pipe centerline the symmetry boundary conditions are: 0&0,0 r t r u v (8) pressure gradient at the wall at a particular time is calculated from the momentum equation and it is given by: r u v r u r u rx p 2 1 re 2 2 2 (9) the shear rate is also calculated from the equation: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۷ r u re 2 (10) method of solution the governing equations are discretized using a finite difference approach and the equations are solved using upwind difference method with collocated grid scheme as shown in fig.2. for the numerical analysis, it is convenient to use the governing equations in stream function and vorticity function: r ru (11) x r (12) r u x (13) using these and eliminating pressure the governing equations are transformed to rrrrxr 3 1 2 2 2 1 2 2 2 1 (14) rrrxrxxrr 3 2 2 2 21 (15) r t rr t x t r t xx t rr 1 2 2 2 21 (16) now, to make the governing equations form in non-dimensional and the boundary conditions using the following dimensionless quantities: vvr k cp pr stot t v p p v r vvrvv u u vr r r vr x x v re;;; 2 2 1* ;* )17( *;*;*;*;* by substitution the above dimensionless quantities, in the governing equation of motion yields: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۸ * * 3 * 1 2 * * 2 2 * 1 2 * * 2 2 * 1 * rrrrxr (18) 2 * * * * * 1 2 * * 2 2 * * 2 re 1 * * * * * * * * * 1 rrrrxrxxrr (19) ** 1 2 * 2 2 * 2 prre 1 ** * ** * * 1 rrrxrxxrr (20) a finite-difference technique is applied to solve the governing equations. these three equations eqs.(18), (19), and (20) are to be solved in a given region subject to the condition that the values of the stream function, temperature, and the vorticity, or their derivatives, are prescribed on the boundary of the domain. eq.(18) can be approximated using central – difference at the representative interior point (i , j), then it can be written for regular mesh as: ]2/[)],(ω)())1,(ψ)1,(ψ( )))(2/(()1,(ψ)1,(ψ),1(ψ),1(ψ[),(ψ 2 * 2 ** 2 * 2 * 2 *** ** 2 * 2 *** 2 *** )δ(δ)δ(δ )δ(δ))(δ())(δ( xrjijrrxjiji jrrxxjijirjijiji (21) also, a central – difference formulation can be used for eqs.(19), and (20). it is known that such a formulation may not be satisfactory owing to the loss of diagonal dominance in the sets of difference equations, with resulting difficulties in convergence when using an iterative procedure. a forward – backward technique can be introduced to maintain the diagonal dominance coefficient of (ωi,j) in eq.(19) and (θi,j) in eq.(20) which determines the main diagonal elements of the resulting linear system; this technique is outlined as follows (najdat,1987): set; * j,1-i * j,1i1 ψψb and * 1-ji, * 1ji,2 ψψb then approximate eq.(19) by: * * * 3 2 * * 2 2 * * 2 re 1 * * *2 1 * * *2 2 * 1 rrrxrx b xr b r now, if r ff r f ,0b,,, r ff r f ,0 1ji,ji,1 ji,1ji, 1 δδ b if al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۳۹ if x ff x f ,0b,,, x ff x f ,0b ji,j,1i2 j,1iji, 2 δδ where, (f ) refers to ** , to assure the diagonal dominance of the coefficient matrix for )ji, * ji, θω (and)( , which depends on the sign of ( 1b ) and ( 2b ), eqs (19) and (20) are expressed in the following difference forms: 0bnd,0bfor 21 a ] 2 re)b(b3 )(2/[)]1,(ω)(),1(ω)( ),1()ω 2 re ()1,()ω 3 2 re [(),(ω * **21 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (22a) 0bnd,0bfor 21 a ] 2 re)b(b3 )(2/[)]1,(ω)(),1(ω)( ),1()ω 2 re ()1,()ω 3 2 re [(),(ω * **21 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (22b) 0bnd,0bfor 21 a ] 2 re)b(b3 )(2/[)]1,(ω)(),1(ω)( ),1()ω 2 re ()1,()ω 3 2 re [(),(ω * **12 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (22c) 0bnd,0bfor 21 a ] 2 re)bb-(3 )(2/[)]1,(ω)(),1(ω)( ),1()ω 2 re ()1,()ω 3 2 re [(),(ω * **21 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (22d) dimensionless energy equation by using upwind finite difference: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۰ 0bnd,0bfor 21 a ] 2 prre)b(b )(2/[)]1,()(),1()( ),1() 2 prre ()1,() 2 prre [(),( * **21 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (23a) 0bnd,0bfor 21 a ] 2 prre)b(b )(2/[)]1,()(),1()( ),1() 2 prre ()1,() 2 prre [(),( * **21 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (23b) 0bnd,0bfor 21 a ] 2 prre)b(b )(2/[)]1,()(),1()( ),1() 2 prre ()1,() 2 prre [(),( * **12 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (23c) 0bnd,0bfor 21 a ] 2 prre)b(-b )(2/[)]1,()(),1()( ),1() 2 prre ()1,() 2 prre [(),( * **21 * * 2 *2 * 2 ** 2 * 2 * * * **22 ** * * 2 * * **12 ** * r rx r rx rxjixjir ji r rxb rji r rx r rxb xji δ δδδ δδδ (23d) the corresponding boundary conditions at both ends of the heat pipe which are the no slip condition for the velocity and adiabatic condition for temperature. 0 * ;0*,*;* )24( 0 * ;0*,0*;0* x r vr l vr l xat x rxat at the centerline, the symmetry conditions are applied. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۱ )25(0 * ;00,**;0* r xrat at the vapor –wick interface: )26(*20 *1,**;1* dx fghvel qv r xvrxrat according to the coordinate system shown in figure 1, stream function *,** rx is negative in evaporator and positive in the condenser while in adiabatic regain is zero, (borujerdi, 2004) . )( )( ln 1 1 1,* sattsatp vtvp fgh r satt tt x so (27) the solution procedure of the discredited equations is based on a line-by-line iteration method in the axial and radial directions using fortran program. the sequence of numerical steps based on upwind difference is as follows: 1. initialize the velocity, pressure, shear rate and temperature fields ( ,*,*,*,* pvu ). 2. solve eqs.(11) and (12) for u and v. 3. solve eq. (9) for p. 4. solve eq. (10) for τ. 5. solve eq. (20) for θ . 6. check eq. (28) for convergence, if it is satisfied, calculations will be ended. otherwise, replace ( ,*,*,*,* pvu ) and return to step (2) and repeat the above procedure until convergence is achieved. the accuracy of the numerical solution is checked first by summation of the absolute value of the relative errors should be equal or less than (10-4). second, the spot value should approach a constant value. the relative error (err) in the numerical procedure is defined as, (borujerdi, 2004): 4101 1 cells n nn err (28) where superscript ( n ) refers to the previous iteration and term ( )refers to ( =u, v, p, τ, θ). a cylindrical heat pipe with water as working fluid is selected, in which the length of the evaporator is the same as the length of the condenser and a comparatively long adiabatic section is considered. the pipe dimensions are taken to be (l/r =5), increment in space coordinates are (δx=0.05) and (δr =0.1). the computation is done for a mesh (101×11), reynolds number (4 and 10), and the prandtl number taken is (pr=0.00368). in the present analysis, the axial conduction along the heat pipe wall is neglected. the evaporator is maintained at constant temperature over its entire length and the condenser is cooled uniformly and is also kept at constant temperature. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۲ results and discussion a computer program has been developed for predicting the stream function, radial and axial velocities, and temperature, pressure, and shear rate fields of vapor flow along the copper-water heat pipe. using this program, a symmetric heat addition and rejection conditions are observed, as shown in fig.1. the stream function fig.3 at the wall increases linearly in the evaporator, decreases linearly in the condenser and is steady in the adiabatic region because of uniform inflow and outflow boundary conditions. from the axial variation of temperature graph fig.4 it is found that the temperature increases in the evaporator section, decreases in the condenser section, and the minimum temperature occurs in the condenser region. as the temperature in the evaporator increases, the vapor density in this section also increases and molecular mean free path becomes small compared to the vapor core diameter. because of the vapor condenses and releasing its latent heat of vaporization to the provided heat sink. when the reynolds number is small, the streamlines are in the direction of increasing axial distance and the axial velocity component is positive everywhere with a transition to zero value occurring in a thin layer at the walls which is observed from fig.5. the axial velocity profile becomes fully developed in a short distance and stays parabolic all along the length of the heat pipe. because of the length of evaporator and condenser section is equal, and then the two quantities of evaporation and condensation of vapor are equal. also the radial velocity is negative in the evaporator section, zero in adiabatic section and positive in the condenser section, because of the flow direction is assumed negative of downward and positive of upward direction, as shown in fig.6. figure 7 illustrates the pressure distribution along the heat pipe space centerline for various reynolds numbers. it can be seen that as the reynolds number increases, the pressure distributions shift up without considerable change in their overall shapes. as the reynolds number increases the pressure in the condenser section is more recovered. the pressure distribution in the adiabatic section is a straight line similar to poiseuille flow results, while the profiles in the evaporator and condenser section demonstrate the effects of pressure head absorbed or created by evaporation or condensation, due to the small pressure drop along the heat pipe at evaporator and condenser sections. the shear rate as shown in fig.8 is found to be symmetric. similar pattern follows for pressure distribution and the decrease in vapor pressure occurs smoothly in evaporator section, remains steady in the adiabatic section and then increases smoothly in the condenser section because of uniform inflow and outflow boundary conditions are equal. the numerical analysis have shown that for the reynolds number (re=4, 10), the shear stress becomes zero at a point very close to the end of the condenser. however, as the reynolds number increases, the flow reversal point moves backward toward the adiabatic section. under this condition, the reversed flow region extends from the flow reversal point to the end of the condenser. to verify our numerical solution we have recovered the heat pipe. a computer code, developed in the present work based on the fortran language, has been validated using the results based on similar problem with those reported by (rajashree and sankara, 1990), as shown in fig.9 shows stream function comparison with previous study. this demonstrates that the present numerical analysis a good agreement for predicting the stream function distribution at reynolds number (re=4). conclusion a numerical study is investigated the flow, temperature, velocity, pressure, and shear stress distributions for a horizontal heat pipe based on the obtained results in the present study, finding are: 1at low and moderate reynolds numbers, the present analysis predicts very small vapor temperature drop along the heat pipe. due to the small pressure drop along the heat pipe. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۳ 2the results show the stream function at the wall increases linearly in the evaporator, decreases linearly in the condenser and is steady in the adiabatic region because of uniform inflow and outflow boundary conditions. 3also, it can be seen that as the reynolds number increases, the pressure distributions shift up without considerable change in their shapes. 4the numerical analysis have shown that for the low and moderate reynolds number, the shear stress becomes zero at a point very close to the end of the condenser. 5the results have been compared with the available numerical data which have been done in the literature and have shown a good agreement. references [1] f.doran, 1989, “heat pipe research and development in the americas,” heat recovery systems and chp, vol.9, pp.67-100. [2] r.rajashree and k. sankara, 1990, ‘‘ a numerical study of the performance of heat pipe,’’ indian j. pure appl. math, 21(1), pp: 95-108. [3] m. m. chan and a. faghri, 1995, “an analysis of the vapor flow and heat conduction through the liquid wick and pipe wall in a heat pipe with single or multiple heat sources,” int. j. heat mass transfer, vol. 33, no. 9, pp. 194. [4] n. zhu and k. vafai, 1999, “analysis of cylindrical heat pipe incorporating the effect of liquid-vapor coupling and non-darcian transport-a closed form solution,” int. j. heat mass transfer, vol. 42, pp. 34053418. [5] s. j. kim, j. k. seo and k. h. do, 2003, “analytical and experimental investigation on the operational characteristics and thermal optimization of a miniature heat pipe with a grooved wick structure,” int. j. heat mass transfer, vol. 46, pp. 2051-2063. [6] a. nouri-borujerdi and m. layeghi, , 2004, “numerical analysis of vapour flow in concentric annular heat pipes,” transaction of asme: journal of heat transfer, vol. 126, pp. 442-448. [7] y. h. yau , 2007, “application of a heat pipe heat exchanger to dehumidification enhancement in a hvac system for tropical climates – a baseline performance characteristics study,” international journal of thermal sciences , vol. 46, pp.164 -171. [8] david b. sarraf, sanjida tamanna, and peter m. dussinger, 2008, “pressure controlled heat pipe for precise temperature control,” space technology and applications international, american institute of physics, pp. 3-11. [9] a. nouri-borujerdi , 2004 “a numerical analysis of vapor flow in concentric annular heat pipes,” transaction of asme: journal of fluids engineering, vol. 126, pp.442448. [10].najdat n., 1987 “laminar flow separation in constructed channel”, ph.d. thesis, michigan state university. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤٤ . fig.(2) the discretized domain rorv evaporator condenseradiabatic section solid wallwick qe qc vapor space u , x v , r fig. (1) schematic of a cylindrical heat pipe jn=jn-1+∆r j3=j2+∆r j2=j1+∆r im=im-1+∆xi3=i2+∆xi2=i1+∆xi1=0 ∆r ∆x j1=0 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤٥ (a) (b) fig. (3) distribution of stream function at the wall a) re = 4 b) re = 10 (a) (b) fig. (4) distribution of temperature near the wall a) re = 4 b) re = 10 (a) (b) fig. (5) distribution of axial velocity at the wall a) re = 4 b) re = 10 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤٦ (a) (b) fig. (6) distribution of redial velocity at the wall a) re = 4 b) re = 10 (a) (b) fig. (7) pressure distribution at the wall a) re = 4 b) re = 10 (a) (b) fig. (8) distribution of shear rate at the wall a) re = 4 b) re = 10 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۷ fig. (9) the stream function calculated in this study versus that of (rajashree and sankara, 1990), at the wall for (re = 4) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 126 experimental study of the effect of zinc borate on flame retardancy of carbonkevlar hybrid fibers reinforced composite materials mushtaq t.ali. albdiry al-qadisiya university college of engineering ali i. al-mosawi technical institute-babylon mechanical department dr. abbas a. al-jeebory al-qadisiya university college of engineering abstract this study aims to investigate possibility to increase the flame retardancy for composite materials by addition of a flame retardant material which represent the zinc borate as a coating layer of (4mm) thickness on the surface of composite material consist of araldite resin reinforced by hybrid fibers from carbon and kevlar fibers as a consecutive layers which be as a woven roving )º 90 º 0( . then, this system (flame retardant material and composite material) was exposed to a direct flame which generated from oxyacetylene flame (up to 3000ºc) and gas flame (2000ºc) under different exposure distances (10,15, and 20mm), and study the range of resistance of flame retardant material layer to the flames and protected the substrate where we used the method of measuring the surface temperature opposite to the flame where we obtained the better results with large exposed distance and large percentage from protective layer which is zinc borate (30%) for both types of flames , as well as the flame resistance will be increased with decrease the flame temperature . keywords: hybrid composite material,, flame retardant material, zinc borate. اد مرآبة مقواة بأليافوعلى إعاقة الّلهب لم خارصينتأثير بورات ال عملية لدراسة هجينةفالر الي آ-آاربون الخالصة بورات مثل توالتي مادة معيقة لّلهب مكانية زيادة إعاقة الّلهب للمواد المرآبة عن طريق إضافة ه الدراسة لبحث ا هذ تهدف من المكونة من راتنج اإلرلدايت المقوى بألياف هجينة على سطح المادة المرآبة (4mm) بسمك بشكل طبقة طالء الخارصين ض ربعدها ع . ) º 90 º 0( ظفائر محاآة ثنائية اإلتجاه طبقات متتابعة والتي تكون بشكل ألياف الكاربون وألياف آيفالر بشكل ة لّلهب المادة ا(هذا النظام ةولمعيق ر ) المادة المرآب علة ُأوآسي أستيلينية إلى ّلهب مباش د من ُش ن بدرجة حرارة متول أآثر م (3000ºc) رارة ة ح ة بدرج علة غازي ن ُش د م ب متول ة (2000ºc) وله رض مختلف سافات تع (20mm,15mm,10mm) وبم طريقة حيث تم إعتماد ى حمايتها للمادة المرآبة الواقعة تحتها ومدتين ودراسة مدى مقاومة طبقة المادة المعيقة لّلهب لحرارة الُشعل حيث تم الحصول على أفضل النتائج درجة حرارة السطح المقابل للشعلة في قياس درجة الحرارة المنتقلة خالل هذا النظام قياس الشعلتين إضافة ولكال ) 30%سبة ن (خارصين والتي هي بورات ال لطبقة الحامية لنسبة أآبر مسافة التعرض آبيرة و عندما تكون إلى ذلك تزداد المقاومة لّلهب آلما قلت حرارة الُشعلة علي إبراهيم الموسوي بابل-المعهد التقني مشتاق طالب البديري جامعة القادسية عباس عليوي الجبوري.د جامعة القادسية al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 127 introduction fire safety is an integral part of precautions. fire precautions have the objective to minimize the number of and damage from measuring hindering their initiation, limiting their propagation and if possible excluding flash-over. preventing fires or delaying them makes escape possible over a longer period of time. as a result, life, health, and property are efficiently protected [1]. since plastics are synthetic organic materials with carbon and often high hydrogen contents, they are combustible. for various applications in the building, electrical, transportation, mining, and other industries, plastics have to fulfill flame retardancy requirements laid down in mandatory regulation and voluntary specification. the objective in flame retarding polymers is to increase ignition resistance and reduce rate of flame spread [2]. one way to better protect combustible materials against initiating fires is the use of flame retardants , which are substances that can be chemically inserted into the polymer molecule or be physically blended in polymers after polymerization to suppress , reduce , delay or modify the propagation of a flame through a plastic materials. there are several classes of flame retardants; halogenated hydrocarbons (chlorine and bromine containing compounds and reactive flame retardants): inorganic flame retardants (boron compounds, antimony oxides, aluminum hydroxide, etc); phosphorus containing compounds; nitrogen containing flame retardants. depending on their nature, flame retardants can act physically or chemically [3]. 1the physical action occurs by: a. cooling: the additives cool the substrate to a temperature below the combustion temperature. b. formation of protective layer: a solid or gaseous protective layer, which excludes the oxygen necessary for the combustion process (e.g. phosphorus compounds). c. dilution: the inert gases from the additive dilute the fuel in the solid and gaseous phase (e.g. aluminum hydroxide). 2the chemical action occurs by: a. reaction in gas phase : the radical mechanism of combustion is interrupted and exothermic reaction are stopped . system cools down (e.g. halogenated flame retardants). b. reaction in solid phase: by forming carbonaceous layer on the polymer surface (e.g. phosphorus compounds). flame retardant materials flame retardants are substances used in plastics, textiles, electronic circuitry and other materials to prevent fires. there are several types of flame retardants as mentioned above, one of these types is inorganic flame retardants. few inorganic compounds are suitable for use as flame retardants in plastics, since such compounds must be effective in the range of decomposition temperature of the plastic, mainly (150ºc 400ºc). inorganic flame retardants don't evaporate under the influence of heat ; rather they decompose ; giving off non-flammable gases like water , carbon dioxide , sulphur dioxide , hydrogen chloride , etc. mostly endothermic reaction . in the gas phase , these act by diluting the mixture of flammable gases and by shielding the surface of the polymer against oxygen attack [4] . the inorganic flame retardants act simultaneously on the surface of the solid phase by cooling the polymer via endothermic breakdown process and reducing the formation of pyrolysis products. in addition , as in the case of inorganic boron compounds , a glassy protective layer can form on the substrate , fending off the effect of oxygen and heat[5] .as example to inorganic flame retardants is zinc borate , aluminum hydroxide , magnesium hydroxide , and antimony oxides . zinc borate is used as a flame retardant and smoke suppressant for wide range of plastics, rubber, paper, and textiles. it can replace antimony oxide as synergist in plastics and rubber to enhance the activity of primary flame retardants by stepwise releasing the radicals in a wide variety of end – use products . it is also used in paints, adhesives, pigments and ceramic industries. table 1 shows the characterizations and properties of zinc borate. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 128 table (1): characterizations and properties of zinc borate [3] mol wtph density g/cm3 melting point °c appearance property 434.62 7.6 3.64 980 white crystalline value composite materials composite material is a material consisting of two or more physically and (or) chemically distinct phase, suitably arranged or distributed. a composite material usually has characteristics that are not depicted by any of its components in isolation [6]. generally, the composite material contains two elements: 1matrix material: it is the continuous phase; it may be metal, ceramic or polymer matrix. the polymer matrix is considered the best because of its mechanical and thermal properties, and also it can reinforced by a large fiber volume fraction compared with metal and ceramic matrix. in addition to the low cost and easy fabrication, as example for this materials araldite resin, polyester, and epoxy resin. araldite resin belong to epoxy group which has excellent thermal and physical properties, and usually used in composite materials for different applications, where it distinct by excellent adhesive capability especially to fibers, also it retain constant dimensions after dryness [7]. 2reinforcing material: the distributed phase is called reinforcement, many reinforcement materials are available in a variety of forms; continuous fibers; short fibers; whiskers, particles...etc. reinforcements include organic fibers such as carbon and kevlar fibers, metallic fibers, ceramic fibers, and particles [8]. high strength, and high modulus carbon fibers are of about (7-8µm) in diameter and consist of small crystallites of turbostratic graphite, one of the allotropic forms of carbon[9]. kevlar is an organic aramid fiber with (3100 mpa) tensile strength, and (131,000 mpa) elastic modulus. a density approximately one-half of aluminum, good toughness, in addition it is flame retardant [10]. flame retardancy test this test is used for thermal isolators which exposed to elevated temperatures exceed (3000ºc) as in the fires case. the heat of this test generated from thermal torch (oxyacetylene and gas). there are two methods to measure the temperature of material in this test [10]: 1surface temperature; in this method, a thermocouple puts on the opposite surface to the torch for calculate the amount of heat transmitted through flame retardant material and composite material. this method used in this study . 2depth of damage; after exposition, the material to the flame at specific time, we will measure the depth of penetration leaves on material surface. experimental work 1materials: there are three types of materials employed in this study: a. flame retardant material, zinc borate 2335 (2zno.3b2o3.5h2o) was used as a flame retardant, which supply from c-tech corporation. table 2 shows the chemical composition of zinc borate. table (2): chemical composition of zinc borate compound zinc oxide boric anhydride water of hydration impurities symbol zno b2o3 h2o content(%) 37 47 14 2 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 129 b. matrix material, araldite resin (cy223) with density of (1.15-1.2 g/cm3) which belong to epoxies group was used in this study. figure (1) shows the chemical structure of araldite resin. c. reinforcing fibers: two types of fibers were used : c.1carbon fibers, a woven roving fibers )º 90 º 0( with density of (225 g/m3). c.2kevlar fibers, a woven roving fibers )º 90 º 0( with density of (285 g/m3). these types of fibers used as consecutive layers in same matrix . figure (2) shows the chemical structure of kevlar fibers. 2preparation test specimens: specimens of flame retardancy test are a square shape, as shown in figure (3) with dimensions (100 ×100mm), and (10mm) thickness, which it consist of two layers: aflame retardant material layer with (4mm) thickness represented by zinc borate. bcomposite material layer with (6mm) thickness, it contains carbon and kevlar fibers which used as consecutive layers in araldite resin . 3flame retardancy test . two types of torch flame were used, oxy-acetylene and butane-propane flame. the system (contains flame retardant material and composite material) was exposed to these flames under different exposure distances (10, 15, and 20mm). figure (4) shows the mechanism of flame retardancy test, surface temperature method used here to calculate the amount of heat transmitted through flame retardant material and composite material. table (3) shows the temperatures of flames used in this study . table (3): temperatures of flames gas symbol temperature,ºc oxyacetylene c2h2 3000-3300 butane-propane c3h8-c4h10 2000 results and discussion from the results obtained by flame retardancy test, we can see : figure(5) represents the flame retardancy test for composite material with zinc borate as a surface layer at exposed distance (10mm) , the temperature of the opposite surface to the torch begins to increase with increasing the time of exposition to the flame . during this stage , zinc borate (10 %) has a water of hydration in its chemical structure , therefore , it released this water to extinguish the fire through cooling , in addition , zinc borate will formed glassy coating layer which protecting the substrate (composite material) and the fire spread will decrease[5] . this process of released water and formation of glassy coating layer will be increased as the zinc borate increased to (20 %, and 30 %). figure (6) shows the behavior of zinc borate with exposed distance (15mm). when the amount of flame retardant layer is (10 %), and with this exposed distance the time of break down of the retardant layer will be increased, because of decomposition of zinc borate and release the water, which dilute the ignition zone and the formation of protected layer will stay to longer time[4]. this state will be increased with increasing zinc borate content to (20 %, and 30 %). as a result, when the exposed distance to flame increased to (20mm), the time necessary to break down of flame retardant layer will increase and the combustion gaseous will reduced and there will be a less plastic to burn due to water of hydration and protected glassy coating layer[5], and this protection will improves with increasing flame retardant percentage to (20 %, and 30 %). all that will rise the time of break down for zinc borate layer and substrate composite material as shown in figure(7) which represents flame retardancy test for zinc borate layer with exposed distance(20mm) . from all figure we obtained the better results with large exposed distance and large percentage from protective layer which is zinc borate (30%) for both types of flames , as well al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 130 as the flame resistance will increase with decrease the flame temperature as illustrated in the diagrams between surface temperature and time of flame exposition . conclusions from this study, we concluded that: 1increasing the flame retardancy as the zinc borate content increased . 2the resistance to flame spread will increased with increasing of exposed distance , due to decreased of the heat transmitted to flame retardant material which will rise the stand of glassy coating layer against flame . 3the flame retardancy is increased as the flame temperature is decreased. references 1jürgen h.troitzsch “ overview of flame retardants ” , chimica oggi/chemistry today , volume 16, january/february 1998 . 2huy k. tran , christine e. johnson , daniel j. rasky , and frank c.l hui “ phenolic impregnated carbon ablators (pica) as thermal protection systems for discovery missions ”, nasa technical memorandum 110440 , april 1997. 3edward a.myszak “ use of submicro inorganic flame retardants in polymeric systemic ”, nyacol nano technologies, inc. 2000. 4ali ibrahim moslem “ study using of antimony trioxide material as a flame retardant material ” , m.sc. thesis , engineering college , babylon university , 2003 . 5heinrich horacek and stefan pieh “ the importance of intumescent systems for fire protection of plastic materials ”, polymer international ,49,2000. 6george lubin “ handbook of fiberglass and advanced plastics composite ”, first edition , 1975. 7d.hull “ an introduction to composite materials” , cambridge university press, 1981 . 8phillip s.waldrop “ plastic composite in the 21st century”, nait conference , 2000 , 1-8pp . 9marcus langley “ carbon fibers in engineering ”, mcgraw-hill book company ltd,1973. 10e.p.degarmo, j.t. black, and r.a. kohser “ materials and processes in manufacturing ” , eighth edition , john wiley & sons , 1999 . al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 131 ch3 ch3 ch3 ch3oh o o n figure (1): chemical structure of araldite resin[10]. ch2-chch2-o -c -o-ch2-ch-ch2-o -c -o-ch2-ch-ch2 co co – nh nh figure (2): chemical structure of kevlar fibers[10]. figure (3): specimen of thermal erosion test composite material layer flame retardant material layer 4mm 6mm 00.0000 specimen holder sliding slotter measuring temperature unit flame thermocouple figure (4): mechanism of flame retardancy test al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 132 0 5 10 15 20 25 30 35 40 45 50 0 20 40 60 80 100 120 140 160 180 200 butane propane torch %10 zinc borate %20 zinc borate %30 zinc borate 0 1 2 3 4 5 6 7 8 9 10 0 20 40 60 80 100 120 140 160 180 200 oxy-acetylene torch %10 zinc borate %20 zinc borate %30 zinc borate figure (5): flame retardancy results for zinc borate layer with exposed distance (10mm) time, sec su rf ac e t em pe ra tu re , º c time, sec su rf ac e t em pe ra tu re , º c 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 20 40 60 80 100 120 140 160 180 200 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 0 20 40 60 80 100 120 140 160 180 200 figure (6): flame retardancy results for zinc borate layer with exposed distance (15mm) su rf ac e t em pe ra tu re , º c time, sec time, sec su rf ac e t em pe ra tu re , º c 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 20 40 60 80 100 120 140 160 180 200 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0 20 40 60 80 100 120 140 160 180 200 figure (7): flame retardancy results for zinc borate layer with exposed distance (20mm) time, sec su rf ac e t em pe ra tu re , º c time, sec su rf ac e t em pe ra tu re , º c al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 483 temperature control of high power microprocessor ass. proff. dr. abbas alwi sakhir aljeebori ass. lecturer mahmoud a .hassan al-qadisiyah university al-qadisiyah university college of engineering college of engineering doctor_abbas2001@yahoo.com hasaaneng@yahoo.com abstract active control of the die-level temperature is desirable during production testing of high power microprocessors, so as to ensure accurate performance classification. the analysis in this research demonstrates fundamentals limits of temperature control for typical devices under test conditions. these limits are identified for specified control power to die power ratios. the effects of test sequence deign and device package design on the temperature control limits are also examined. the theory developed can be applied to any thermal control problem where a conductive medium separates the control source from the location where control is desired. as a dimensional example, when the die power density (qd = 10 w/cm2 ) and frequency of the die power variation ( ω =10 hz) with ( t∆ = 4k ) , the required control power density ( qc = 63 w/cm2 ) . this performance is much better than for ideal temperature control where the control magnitude was found to be (173 w/cm2 ) with no change with the convective heat transfer coefficient f t when it varies from 500 w/m2.k to 2000 w/m2.k. keyword: thermal control, microprocessors, temperature control, power density السيطرة على درجة الحرارة للمعدات االلكترونية ذي القدرة العالية محمود عبد حسان. م.د عباس عليوي الجبوري م.م.أ قسم الهندسة الميكانيكية\ كلية الهندسة \جامعة القادسية الخالصة التحليـل . إلنتاج والفحص للتحقق من دقة األداء خالل عمليات ا " السيطرة على درجة حرارة مادة المعالج االلكتروني مهمة جدا . الرياضي في هذا البحث، يستخدم أساسيات انتقال الحرارة لسيطرة على درجة حرارة معدات الكترونية نموذجية تحت الفحص mailto:doctor_abbas2001@yahoo.com mailto:hasaaneng@yahoo.com al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 484 توضـيح ، تم"أيضا. على درجة حرارة المعالج االلكتروني كذلك تم دراسة تأثير عمليات التصميم والفحص على حدود السيطرة =qd عملية السيطرة بمثال نموذجي لمعالج الكتروني ذو قدرة 100 w/cm2 10 وتردد hz حيث وجـد أن القـدرة الالزمـة =qcللسيطرة هي 63 w/cm2 وهذا األداء أفضل من نضيره في عمليات السيطرة العادية حيث يحتاج المعالج األلكتروني الى qc= 173w/cm2رة بالحمل مع تبات معامل انتقال الحراhc 500 ولمعدالت من w/m2.k 2000 إلى w/m2.k. nomenclature )( xa : cross-sectional area of ihs fin, m2 oa : base cross-sectional area of ihs fin, m 2 ta : thermal diffusivity, m 2/s dsbi : biot number for die side of ihs, tkrb / ihsbi : biot number for top side of ihs, kbhc / b : integrated heat spreader ihs thickness, m pc : specific heat at constant pressure, j/kg.k ch : average convective heat transfer coefficient, w/m 2.k i : the imaginary number, 1 k : thermal conductivity, w/m.k l : fin length, m l : unsteady diffusion scale in ihs, ta2ω / , m -1 m : mass of die per unit area, kg/m2 dq : die power density, 2mw / daq : corrected die power density, 2mw / cq : control power density, 2mw / tr : thermal contact resistance, k. m 2/w s : ratio of die time scale to ihs diffusion time scale airt : air temperature, k al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 485 diet : die temperature, k reft : reference temperature-often take as zero, k bft : ihs die side temperature, k t : time, s x : real part of complex temperature solution, k x : distance from reference face of integrated heat spreader, m γβα ,, : phase shift, rad α : shaped fin geometry factor λ: lumped frequency response of die, tp rmc1 / , s -1 θ : temperature defect, (t-tair), k ω : frequency of die power variation, rad/s introduction all high-performance electronic devices are subject to a 100% functional test prior to being shipped by the manufacturer (pfahnl, et al., 1999). high power microprocessor devices are also subject to a classification test to determine the effective operating speed of the device. during this classification test, the goal of control is to keep the temperature of the die at a single set temperature while the device power is varied between 0% to 100% power in a predetermined test sequence. temperature increases over the specified test temperature decrease the signal propagation speed within the device, and an excessive temperature rise above the test temperature can result in the device being classified in the wrong category (e.g., a l ghz device classified and shipped as a 950 mhz device). the manufacturer normally specifies a die-level test temperature range; a typical test temperature specification is 85oc 0oc/ + 3oc. as microprocessor device powers have increased and device sizes have decreased, the power densities in packaged microprocessor devices have approached levels of 50 to 100 w/cm2 ( tadayon, 2000). with test sequences rapidly varying the device power at these power densities, active temperature control is essential to holding the die temperature within tolerance. because the tests are being performed on packaged devices, thermal control cannot be applied to the die itself. instead, control heating and cooling must be applied to some external part of the packaging. this separation of the control point from the die limits the achievable temperature control tolerances for given test sequences and device powers. an estimate of the required control power is needed in the early design phases of temperature control systems for test equipment, so that the heating and cooling system capabilities can be al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 486 specified. for this reason, an analysis of the packaged device by itself, without any consideration of the control system, is very useful in determining the required minimum heating and cooling capacities as well as in determining the effects of varying the test sequence design and package design on the thermal control limits. this research develops such a model. mathematical model semiconductor packaging encompasses a wide range of geometries, die architectures, and materials. in this research, we consider the arrangement shown in fig. 1. the device consists of a silicon die mounted on single or multiple interposer/interface layers. an integrated heat spreader (typically plated copper) is mounted on top of the die structure with a very thin layer of a thermal interface material or grease between the die and the heat spreader. the heat spreader area is typically much larger than the die area and provides a bonding surface for an external heat sink in the final device application. we consider situations in which the die's heat generation is essentially uniform over its area, with no large-scale variations. our focus is on temperature under test conditions. during testing, the packaged device is held in a test socket which is itself temperature controlled to the desired test temperature. the socket isolated from the test electronics(pfahnl, et al., 1998). work by viswanath et al.(2000) and sweetland(2001) has shown that the thermal resistance between the die structure and the interposer layer is typically much higher than the thermal resistance between the die structure and the surface of the integrated heat spreader. for this reason, only the die and integrated heat spreader will be considered in the transient model (the interposer side of the die is considered adiabatic). if the architecture of a particular device allows nonnegligible heat transfer to the interposer, the present results will provide a upper bound on the required control power and a conservative basis for design. temperature gradients within the die are taken to be small, effectively making the die a lumped object with uniform internal heat generation. at low frequencies, this approximation is easily justified because the thermal resistance of the interface layer is large compared to that of the die, unless the dies are very thick (> 1500 mμ ). for higher frequencies, analysis of the unsteady conduction in the die, with heat generation confined to the face opposite the integrated heat spreader, shows that the die follows lumped response for the frequencies of importance to the die's thermal response. to starts the transient analysis, only the temperature profile within integrated heat spreader (ihs) will be considered. for mathematical convenience, that problem can be further decomposed into the two parts shown in fig. 2. the first part is for the ihs with an adiabatic back face and a front surface subject to convective cooling and the radiative control power profile (fig. 3a). the second part is for the ihs with an imposed surface flux from the die on one face and convection on the other face (fig. 3b). the two results are then combined using superposition. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 487 ihs temperature response to control input the steady periodic transient response to the two cases in fig. 3 can be calculated using a complex temperature approach(carslaw and jaeger, 1959). consider an infinite slab with one side adiabatic as shown in fig. 3a. the other face is subject to convective boundary conditions, an average heat transfer coefficient hc with an air temperature tair= 0, and a control flux q(t)= qccos( tω ). using complex analysis methods, it is assumed that the solution to the temperature profi1e in the complex plane takes the form: )().( tτxxw = (1) where tωietτ =)( and 1-i = . the conduction equation in the integrated heat spreader is t w a 1 x w t 2 2 ∂ ∂ = ∂ ∂ (2) so with an assumed solution of eq. (1), this can be written t 2 2 a ωi dx xd = (3) which has the general solution )exp()exp()( += x a iw cx a iw -ctx t 2 t 1 (4) the boundary conditions on eq. (3) are as follows: 0x = 0 dx dx = (5) bx = xhq dx dx kcc =+ (6) yields ][ ) ( 1)xl(i1)xl(i22 bl c ee bkl(a bi)-aeq x ++ + + = (7) where { sin(bl)][cos(bl)-1ebl bl bi a bl2ihs ++= ))(cos( + }sin(bl)]-ble bl2 )[cos( (8) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 488 { sin(bl)]-[cos(bl)-1-ebl bl bi b bl2ihs ))(sin(= + }sin(bl)]ble bl2 +)[cos( (9) to find the solution to the temperature profile in the integrated heat spreader in the real domain, the real part of tωixe must be taken xl)]-tωbsin(xl)-tωa bakl eq xetxt 22 x-bl c tωi + + == cos([ )( )re(),( )( xl)]tωbsin(xl)tωa bakl eq 22 xbl c +++ + + + cos([ )( )( (10) ihs temperature response to die input an identical approach can be used to find the temperature profile of the integrated heat spreader subject to heat input from the die, but with different boundary conditions are as follows: 0x = xh dx dx k c= (11) bx = dx dx kqd = (12) with eq. (4) for x, the boundary condition at x= 0 yields: )()( 21c12 t cchc-c a ωi k += (13) this equation can be solved to express the new c1 in terms of the new c2: 2 c 2 c c 2 c 2 21 kl2lkh2h iklh2h-kl2 cc )( )()( ++ + = (14) in which ta2ωl /= as before. defining 2 c 2 c kl2lkh2hd )(++= , 2c2 h-kl2e )(= , klh2f c= (15) eq. (14) can written al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 489 d fie cc 21 )( + = (16) and the solution for x becomes [ ( ) ( ) ]x a ωi x a ωi d fie cx tt 2 expexp + + = (17) substitution of this expression into the boundary condition at x= b produces [ ]bli--blblibl2d e1ified e -ee1iklcq ))(()( +++= (18) which may be rearranged to )]sin()cos([)]sin()[cos( blnblg d e -bl-ble klc q -bl bl 2 d += + )]cos()sin([)]sin()[cos( blnblg-i d e -blblie -bl bl ++ (19) where f-eg = and fen += (20) with the following additional defintions )]sin()cos([)]sin()[cos( blnblg d e -bl-blep -bl bl += (21) )]cos()sin([)]sin()[cos( bln-blg d e blbler -bl bl ++= (22) the solution for the constant c2 may be written ) ( 22 d 2 rkl(p ri)-pq c + = (23) the function x is therefore [ ])()( ) ( 1ixl1)xl(i22 d ee d fie rkl(p ri)-pq x ++ + + + = (24) the solution for the temperature in the heat spreader is again found by solving for the real part of tωixe . setting d frep u .. + = and d e.r-fp v . = (25) the final expression for the temperature of the heat spreader is al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 490 xl)]-tωvsin(-xl)-tωu rkl(p eq xetxt 22 -xl dtωi cos([ ) )re(),( + == xl)]tωrsin(xl)tωp rkl(p eq 22 xl d +++ + + cos([ ) (26) temperature response of die the die normally has small thermal resistance and can be treated as isothermal for the frequencies of interest. its temperature response is described by t bf d die p r t-t -tωq dt dt cm )cos(= (27) where m is the mass of die per unit area and bft is the die-side surface temperature of the integrated heat spreader. this equation neglects the heat capacity of the thermal interface material between the die and the ihs. for ideal temperature control, where there is no change in die temperature, and taking the desired die temperature be zero a, the equation for the ihs back face temperature becomes: )cos(.)cos(. πtωrqtωr-qt tdtdbf +== (28) control profile calculation with specified die temperature tolerance the two previous analyses identify the control profile for the cases where the die temperature is constant(ideal control)or where the temperature of the back face of the ihs is held constant. to reach actual practice, we must go a step further and allow the die temperature to fluctuate within specified tolerance limits for a given die power profile(non-ideal control). we now adapt the previous analyses to obtain the control power profile for a varying die temperature. in the lights of eqs.(27) and (28), we may assume that for non-ideal control, the back face temperature of the his has the form )cos(.. βtωrqmt tdbf += (29) where the scaling factor m takes on a value between 0 and 1. upon substituting eq. (29) into eq. (27) and integrating, we obtain al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 491 { )]cos()cos()[cos( )( tωωtωλβm1 ωλmc q t 22 p d die +++ = }t)]ωcos(ω-t)ωsin(λ[βsin (30) where tp rmc1λ /≡ ( λ1 / is the lumped-capacity time constant associated with eq. (29). of interest here is the magnitude of the fluctuation of diet . by setting this magnitude equal to the allowed tolerance tδ of the die temperature, a relationship between the scaling factor m and the phase shift β is obtained: )()/ 222dp2 λωq2tδ(mc1-βcosβ-cosm ++±= (31) the goal is to minimized m for a given die power profile, since a smaller value of m leads to a smaller required control power. eq. (31) can be differentiated with respect to β 0 λωq2tδmc1-β ββ β βd dm 222 dp 2 = ++ = )()/(cos sincos sin m (32) this equation has to two roots: 0β = and πβ = . for the case 0tδ = , the solution must be 1m = , not 1-m = , so the correct root is πβ = . hence 2 td 22 d p λω1 rq2 tδ -1λω q2 tδmc -1m )/()( +=+= (33) which determines the magnitude of the fluctuation of bft . the die temperature profile is }{ )cos()cos( )( )( tωωtωλ ωλmc m-1q t 22 p d die ++ = (34) the heat flux from the die into the heat spreader, dsq , may be calculated from eqs. (29) and (34) t bfdie ds r t-t q = { } )sin( )( )( )cos( )( ( tω ωλrmc m-1ωq tωmq ωλrmc )m-1λq 22 tp d d22 tp d + ++ + = )cos()cos(. γtωqγtω ωλ ωmλ qq da22 222 dds +≡++ + = (35) where al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 492 ) ( (tan 22 -1 ωmλ 1)-mωλ γ + = (36) and the amplitude daq is defined as shown. the heat flux from the die into the integrated heat spreader is reduced in magnitude and shifted by a phase lag γ . these revised solutions for the magnitude and phase shift of the flux and temperature at the die side of the ihs can now be used the following equation { }t)ω]sin(αasin-αbtωαbαa bakl eq2 t 22 bl c ihs cos[)cos(]sincos[)( ++ + = { }t)ω]sin(blvcos-blutωblvblu rpkl eq2 22 bld )()sin([)cos()]sin()cos([ )( ++ + + { }t)ω]sin(blrcos-blp-tωblrblp rpkl eq2 22 bl d )()sin([)cos()]sin()cos([ )( + + + (37) by setting ihst in eq. (37) to bft from eq. (39) and setting dq in eq. (37) to daq from eq. (35). upon separating the sine and cosine terms, there obtains: { )]γ-vsin(bl)γ-bluepsqαbαaps bl-3c2 +++ cos(.[].sincos.[ } )cos()sin()cos(.[ tωγblrγblpeps bl3 ++++ + { )]γ-vcos(bl-)γ-bluepsqαa-αbps bl-3c2 sin(.[].sincos.[ + } )sin()cos()sin(.[ tωγblr-γblpepsbl3 ++ )cos(. tωqmrdt= (38) where )( 22 d 1 rpkl q ps + = , )( 22 bl 2 bakl e2 ps + = , )( 22 da 1 rpkl q ps + = (39) since eq. (38) must hold for any time t, the solution for cq and α may be obtained by requiring that coefficients of the sine and cosine terms of eq. (38) vanished separately. { } da d dsda d d c 22 bl q q bi bl -m. q q q q ba αbαae2 ... ]sincos[ = + + { } 22 bl-bl rp )γrsin(bl)γblpe)γ-vsin(bl)γ-blue + +++++ cos([cos([ (40) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 493 { } = + da d d c 22 bl q q q q ba αa-αbe2 .. ]sincos[ { } 22 bl-bl rp )γpsin(bl-)γblre)γ-vcos(bl-)γ-blue + +++ cos([sin([ (41) where )/( tds krbbi ≡ is a biot number for the die side of the ihs. the factors dad qq / , m, and γ depend on the additional groups tδrq td / and λω / . the latter parameter can be written as sbl b rmca2 bl ω λ 2 2 tpt2 )()()( ≡= (42) lateral conduction effects in ihs the function of the heat spreader is to act as a fin, conducting heat laterally away from the die. for the steady components of die power, the ihs will indeed function as a fin. for higher frequency components, however, the fin effect will be limited to a frequency-dependent thermal penetration length in the ihs near the die. only the lower frequency components will have a sufficient penetration depth to influence the control response. in this section, we examine the effect of frequency-dependent lateral conduction on the control requirements. the biot number, ihsbi , for a typical heat spreader is very small, even at the highest ch values considered here (e.g., 0090biihs .= for kmw2000h 2c /= and mm81b .= ), thus, the thermal response of the parts of the spreader beyond the die can be modelled using the unsteady fin equation t θ a 1 θ ka(x) hp x θ dx da xa 1 x θ t 2 2 ∂ ∂ = ∂ ∂ + ∂ ∂ )( (43) where airt-tθ = , p is the perimeter subject to convection, a(x) is the cross-sectional area. a square heat spreader with a square die can be broken into four identical quadrants, by symmetry. the cross-sectional area of the heat spreader can now be expressed as , bxaxa o +=)( , where oa is the area of the fin along the line of contact with the die. equation (43) has been studied extensively, and analytical solutions have been reviewed by aziz and kraus(1995). in the present case, with variable cross-sectional area and time dependent al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 494 boundary conditions, the equation will be solved using discrete methods. the two items of principal interest are the heat flux and the thermal penetration depth that result from a change in base temperature, with the latter corresponding to the temperature of the ihs directly over the die structure. the base temperature is never uniform across the thickness of the heat spreader because the powers are time dependent. nevertheless, this temperature varies over a well specified range, and a bounding value can be used to examine the worst case losses into the fin-like parts of the ihs away from the die. the magnitude of the temperature variation in the ihs over the die can be taken from the previously determined ihs temperature profiles, such as fig. 4. the fin may be divided into the n sections shown in the inset in fig. 9. the temperature of a fin section subject to time varying boundary conditions can be written as ftta i1i +=+. (44) where [ it ] and [ 1it + ] are arrays of the fin temperature at time step i and i+ 1 respectively. the details of the forcing function [ f ] and characteristic matrix [ a ] are standard, and will not be repeated here. the temperature at time step i+ 1 is found by matrix inversion. we used this approach to determine the temperature profile in the fin as a function of time subject to changing base temperature ibt . the fin was broken into 100 segments and the time step tδ was decreased by factors of two until successive changes in the time step produced results that varied by less than c010 o. at all times. results and discussion temperature profile for die and back-face of ihs as a dimensional example when 2d cmw10q /= and hz10ω = with k4tδ = , the required control power profile has a phase shift o2377α .= and a control magnitude of 2 c cmw0563q /.= . this performance is much better than for ideal temperature control where the control magnitude was found to be 2cmw173 / . the resulting temperature profiles for the die and the back face of the ihs are shown in fig. 4 model confirmation in order to provide an independent confirmation of the mathematical solution an implicit finite difference model(mills, 1995) of the die/heat spreader system was constructed. this approach is not very convenient for determining for the required control input magnitude and phase shift, but it is very useful for checking the analysis. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 495 figure 5 shows the die temperature as calculated from the finite difference model for a 10 hz die power with 2d cmw10q /= the control input has 2c cmw0563q /.= and o2377α .= , as predicted by the analysis for a tolerance of k4tδ = . as can be seen, the finite difference model confirms that the predicted control input does control the die temperature to the desired level. limits to control for a given die power profile a knowledge of the required control power profile for a given temperature tolerance in the die can be used to define the control limits for any given system. specifically, for a given die power frequency and amplitude, if the control power is limited to some finite value then the die temperature can be controlled only to some minimum tolerance. tighter temperature control is not possible for that level of control power. over a range of die power frequencies, the control power ratio, dc qq / , can be found for a given die temperature tolerance, scaled into the die power as tδrq td / . by evaluating the control power ratio over a range of frequencies, we may define a control limit plot for a specified set of die conditions. figure 6 shows such control limits over a range of dimensionless frequency, (bl)2. in this graph, 00550biihs .= , 110bids .= , and 760s .= , corresponding to a mμ200 thick die, a 1.8 mm thick copper ihs, wkcm420r 2t /.= , and convective cooling through kmw1200h 2c /= . (those values are typical of test conditions currently being developed (sweetland, 2001)). figure 6 shows that any desired die flux to temperature tolerance ratio can be obtained with sufficient control power, so no theoretical limit to temperature control exists. on a practical level, however, power ratios over 3 or 4 quickly become impractical due to cooling requirements of the effective steady state heat load the sum of the dc components of die power and control power. these results lead to some very important points. the position of the lefthand sides of the curves are defined by the physical configuration of the heat spreader (thickness, conductivity, etc.), whereas the righthand sides are defined by the mass of the die, frequency of the die power profi1e, and thermal interface resistance between the die and the ihs. if the design of the ic device cannot be altered for thermal purposes, as is usually the case, a desired level of temperature control may instead be obtained by designing the circuit test sequence, for example, so that the die power profile always lies to the right side of the figure. we may also evaluate the effect of design changes to the integrated heat spreader and thermal interface between the die and ihs. changing the thermal resistance between the die and the ihs can have a profound effect on the control limits at higher power ratios. this is seen in fig. 7a for kcmw5tδq 2d // = . the effects of changing the thickness of the integrated heat spreader and the die are shown in fig. 7b and fig. 7c, respectively. changing the thickness of the die (and therefore its mass) has the largest impact on the control limits of the device. the increasing the thickness of the ihs also raised the power required for a given level of control. the effect of changing the convective transfer coefficient ch is negligible, with no change observed when ch varies from 500 w/m2k to 2000 w/m2k. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 496 lateral conduction results the heat lost by conduction into the ihs away from the die is found by integrating the flux into the base area, , oa , over a full period of the harmonic power variation. this heat may be viewed as lost control energy. for example, consider a 1 cm2 die and that has a 1.8 mm thick heat spreader measuring 3.4 cm by 3.4 cm. the temperature profile in the part of the ihs not above the die is shown in fig. 8 for a i0 hz base temperature variation having a peak-to-peak magnitude of 4 k with hc= 1200 w /m2k. the cyclic heat loss is 0.36 w per fin segment, or 1.44 w for the entire heat spreader. similar calculations have been done for a range of frequencies and for various hc(fig. 9). the results of such analyses can be used in one of two ways to correct the control response for the lateral conduction losses. one approach is simply to add the control losses to the total control power. the second approach is to provide a control heat flux to an area of the heat spreader larger than the die, so as to minimize time-dependent lateral heat loss from the die (in the case of laser heating of the ihs, this amounts to over-illumination of the ihs). the second option is only really possible for higher frequency signals, because at lower frequencies the penetration depth is of the same order of magnitude as the width of the heat spreader. if the penetration depth is defined as the distance from the base of the fin to the point where the temperature fluctuation is less than 0.1 oc, then the penetration depth for the temperature profile shown in fig. 8 is 6.1 mm. illuminating the die area covers 1.0 cm2, illuminating the die area and a sufficient edge area to prevent lateral conduction effects on the die area requires illumination of 4.9 cm2. similarly, the penetration depth for a 40 hz signal is 3.4 mm with over-illumination covering 2.8 cm2; and at 100 hz, the pentration depth is 2.1 mm with over-illumination covering 2.0 cm2. assuming the radiant intensity is uniform over the entire illuminated area, over-illumination requires 4.9 times more radiant power at 10 hz, 2.1 times more at 40 hz and 2.0 times the power at 100 hz. conclusions 1. time-leading temperature control in a distributed-parameter thermal system has been evaluated in one and two dimensions. a particular focus has been the testing of packaged, high-power, integrated circuits. the analysis identifies the control power required to bound the temperature variation of a system having time-dependent self-heating if control is by time-varying heat conduction to a position distant from the location being controlled. 2. the results may be very useful in the design of active thermal control systems for testing of electronic devices and for understanding the impact of electronic test-sequence designs and packaging design on the practical limits of temperature control. three areas of operation for thermal control have been identified. at high frequencies, active control is not required because the temperature deviation without control is below the desired tolerance: steady (dc) cooling is all that is needed. at sufficiently low frequencies, thermal control can be obtained using a system's available control power. for intermediate frequencies, either control is not possible at the system's rated control power and desired temperature tolerance, or larger temperature deviations have to be accepted as a result the system's limitation on control power. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 497 3. this analysis can be applied to any situation where the temperature control source is separated from the active region where temperature control is desired, and should have value for systems other than electronics testing equipment. references aziz, a., and kraus., 1995,”transient heat transfer in extended surfaces”, applied mechanics reviews, 48(7): 317-350. carslaw h.s. and jaeger j.c, 1959, “conduction of heat in solids”, oxford university press, oxford, 2nd edition. mills, a. f., 1995, “heat and mass transfer”, irwin, chicago. pfahnl a.c., lienhard j.h., and slocum a.h., 1999 “thermal management and control in testing packaged integrated circuit devices”. in proc. 34th intersociety energy conversion conf., vancouver bc, 1999. paper no. 1999-0t-2722. pfahnl, a.c., lienhard j.h., and slocum a.h., 1998, “temperature control of a handier test interface”. in proc. ieee intl. test conf., pages 114-118, washington dc. sweetland, m.,2001,” design of thermal control systems for testing of electronics”, ph.d. thesis, massachusetts institute of technology, june 2001. tadayon, p., 2000, “thermal challenges during microprocessor testing”, intel technology journal, q3. viswanath, r., wakharkar v., watwe a., and lebonheur v, 2000, “thermal performance challenges from silicon to systems”. intel technology journal, q3 figure 1: typical cross-section of a high power microprocessor device. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 498 figure 2: schematic diagram of simplified device for transient analysis. qc is the magnitude of the control input and α is the phase shift of the control input. qd is the magnitude of the die power profile. figure 3: schematic drawing of decomposition for solution to transient temperature profile in integrated heat spreader. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 499 figure 4: temperature profile for die and back-face of ihs for 2 d cmw10qhz10ω /, == and k4tδ = . figure 5: calculated die temperature using finite difference model to confirm analytic solution for control input. target k4tδ = with hc = 1200 w/m2k, rt= 0.42 cm2k/w, b=1.8 mm, and qd= 10 w/cm2. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 500 figure 6: control power limits for specified die power amplitude, qd, and die temperature tolerance, tδ , as a function of nondimensional die power frequency, (bl)2. figure 7: effect on control power limits of: ainterfacial thermal resistance; b ihs thickness; and cdie thickness. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 501 figure 8: transient fin temperature profile for 10 hz example. top: temperature variation at base and tip of fin. bottom: maximum/minimum temperature defect along the length of the fin. figure 9: lateral conduction into ihs for various hc: q =cyclic lateral loss into ihs; btδ = temperature fluctuation amplitude of ihs at die edge. insert shows discretization of ihs for numerical solution. 11-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 natural convection in a wavy porous enclosure heated by an internal circular cylinder dr. muneer a ismael mechanical engineering department-engineering college – university of basra email: muneerismael@yahoo.com p.o. box 2067, ashar post office, basra, iraq abstract: natural convection fluid flow and heat transfer of fluid-saturated porous media heated by an internal circular cylinder inside a wavy enclosure is investigated numerically. the 2d enclosure is composed of two isothermal vertical wavy walls and two adiabatic horizontal flat walls. darcy assumption and boussinesq approximation were relied on in this steady, incompressible study. the governing equations were solved using galerkin finite element method implemented in flexpde software package. the performance of enclosure was evaluated by three non-dimensional parameters namely, the darcy-modified rayleigh number ram (100-1000), the waviness ratio (00.35), and the position of the inner heated cylinder (0.45-1.05). the results were presented by visualization of the streamline and isothermal contours and by the local and average nusselt numbers. it was found that the lower the position of the inner cylinder ( =0.45) is the largest the values of nusselt number while the influence of the wall waviness ratio is found to be very small. keywords: natural convection, porous media, enclosure, wavy wall, darcy assumption. . --. : . . (darcy assumption)(boussinesq approximation) . (flexpde) .: ram (100-1000) ،(0-0.35)(0.45-1.05) . (streamlines)(isotherms) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 .( =0.45) . nomenclatures a wavy wall amplitude (m) x,y dimensionless coordinates a aspect ratio greek d diameter of inner cylinder (m) thermal diffusivity of fluid (m2/s) da darcy number thermal expansion of fluid (k-1) g gravitational acceleration (m/s2) waviness ratio h heat transfer coefficient (w/m2k) kinematic viscosity (m2/s) h enclosure height (m) dynamic viscosity of fluid (n/m2s) k permeability of porous media (m2) stream function (m2/s) k thermal conductivity (w/m.k) dimensionless stream function l length (m) density of fluid (kg/m3) nu nusselt number o density of fluid at temperature to (kg/m3) p pressure (pa) dimensionless temperature ram darcy-modified rayleigh number dimensionless position of inner cylinder s distance along l (m) subscripts t temperature (k) av average u velocity vector (m/s) c cold u velocity in x-direction (m/s) h hot v velocity in y-direction (m/s) i inner w average width of enclosure (m) l left x,y 2d coordinates r right 1. introduction fluid flow and heat transfer in porous media have received a pronounced attention in the past few decades. the reason behind this attention is the extensive growing applications of this field in engineering such as solar collectors, thermal insulation, grain storage, filtering and draying process, nuclear research (ingham et al 2002; nield and bejan 2006), production of oil and gas from underground reservoir (clifford et al 2006). the applications extend also to the biological and medical problems (kulasiri and verwoerd 2003; khaled and vafai 2003). most of these applications are simulated by a natural convection process in porous enclosures. different shaped enclosures were investigated to attain a system of high efficient thermal performance. the early reported studies, generally, were focused on the square or rectangular enclosures as in (groos et al 1986; manole and lage 1992; goyoeau et al 1996; baytas and pop 2002). nevertheless the rectangular geometry is still investigating but in different boundary conditions as in (barletta and lazzari 2005) where a square cavity of isothermal walls and an internal concentric circular heating boundary was studied for different cavity inclination angles. the study of (oztop 2007) concluded that the inclination of a partially cooled rectangular enclosure is the dominated parameter on heat transfer and fluid flow. voral et al 2008 studied the effect of amplitude of the sinusoidaly varying temperature profile on the bottom wall of rectangular enclosure for different aspect ratios. another study on square enclosure subjected to localized heating and salting from one side was done by (zaho 2008) where the double-diffusive convective flow was considered (double-diffusive: diffusion of matter caused by temperature gradients and diffusion of heat caused by concentration gradient). in (braga and lemos 2009) a numerical tool was developed to study the natural convection in a composite cavity formed by three distinct regions, clear, porous, and solid region. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 however, a limited group of non-rectangular porous enclosures was investigated basing on darcian and non-darcian assumptions of porous model. the trapezoidal enclosure has been studied by many researchers; in (marafi and vafai 2001) a numerical parallel analysis was developed to study the effect of darcy modified rayleigh number ram, grashof number, and the inclination of the trapezoidal walls. extensive numerical studies, penalty finite element with bi-quadratic element analysis was performed to study the wall inclination, uniform and non uniform heating of the trapezoidal base and wide range of rayleigh, prandtle and darcy parameters are edited in (basak et al 2009) and in another work (basak et al 2009). a right angle trapezoidal enclosure with heated vertical wall and partially cooled inclined wall was studied by (voral et al 2009). three aspect ratios and three locations of cooling part with a range of ram were examined. in addition, the maximum density effect on buoyancy-induced flow and heat transfer was studied in (voral et al 2010). right-angle triangular enclosures were studied numerically for various boundary conditions of the walls, various aspect ratios and ranges of ram (voral et al 2006). in addition, the effect of adding a thin fin inside the right-angle triangular enclosure was investigated in (voral et al 2007). the effect of inserting a square body subjected to four different boundary conditions inside the right-angle triangular enclosure was investigated in (voral et al 2007). because of its complexity, fewer published works about wavy wall(s) enclosures filled with porous media were found. the studies reported in (mahmud and andrew 2004, adjlout et al 2002, mahmud et al 2002, mahmud et al 2003) deal with wavy wall enclosures but limited to clear fluid only. the works of (kumar and shalini 2003, misirlioglu et al 2005, khanafer et al 2009, sultana and hyder 2007) are concerned with wavy wall(s) porous enclosures based on nondarcian assumption. in all these studies, besides to the classical parameters, ra, gr, etc., the effect of phase wavelength and amplitude of the wavy wall(s) were examined. a wavy porous enclosure heated by an internal body has not been seen previously investigated. therefore, the present study try to contribute in this field of investigation by studying the natural convection in a wavy wall enclosure filled with fluid-saturated porous medium heated by inside circular cylinder basing on darcian assumption. 2. mathematical modeling 2.1 physical model generally, the low velocity flow which is the case in porous media flow obeys darcy's law (clifford et al 2006), gu p k (1) where k is the permeability of the porous media, p is the pressure, u=(u,v) is the velocity vector and g=(0,-g) is the gravitational acceleration. the effects of inertia and boundary permeability are ignored in this study i.e. basing the modeling according to darcy assumption which is can be safely applied when darcy number da < 10-4 (clifford 2006). the properties of fluid are considered constant everywhere except the density in the buoyancy term of momentum equation which is boussineq approximation according to the following linear equation of state: oo tt1 (2) hence the equations governed the problem are: continuity, darcy-momentum, and energy equations. the darcy momentum is obtained by differentiating the x-component of equ.(1) with respect to y and that of ycomponent with respect to x and subtracting the resulting two equations. the following dimensional set of equations is obtained. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 y v x u (3) x tkg x v y u (4) 2 2 2 2 y t x t y t v x t u (5) y u , x v and scaling the different variables as follow: w x x , w y y , , ch c tt tt where w is the average width of the enclosure shown in figure 1. thus, the governing equs.(3-5) can be written in the following non-dimensional form: x ra yx m2 2 2 2 (6) 2 2 2 2 yxyxxy (7) where ram is the darcy modified rayleigh number: wttkg w kwttg darara chchm 2 3 . the local nusselt numbers for both wavy surfaces and the inside circular surface are calculated from: k lh nu lll , k lh nu rrr , k lh nu iii (8) where h is the local heat transfer coefficient given by: n t t k h (9) k is the thermal conductivity, ll and lr are the left and right wavy lengths respectively, li is the n is a vector normal to the wall. hence, the local nusselt numbers are as follows: nl nu , nr nu , ni nu (10) the average nusselt number over the surfaces can be written as l sl l,av dsl 1 nu l n , r sr r,av dsl 1 nu r n , i si i,av dsd 1 nu n (11) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 due to symmetry about x=0, and steady-state assumption, the average nusselt numbers along both the wavy walls and the inner cylinder are related according to the overall heat balance; dnulnulnu i,avrr,avll,av (12) 2.2 boundary conditions the enclosure is made of two horizontal flat walls and two vertical wavy walls with inside circular cylinder (figure 1). the space between the inside cylinder and the enclosure walls is filled with fluid-saturated porous medium. the flat horizontal walls are kept adiabatic while the wavy walls and the inner cylinder are isothermal but kept at different temperatures (the temperature of inner cylinder is higher). the position of the inside cylinder can be moved along a vertical line x=0. the definitions of the boundaries and their conditions are as follow: 0,0) y i at y=0 and at y=a, with x ranges: 2 1 2 1 x for both y's 0,0)ii on the left wavy wall a y xay 2 2 sin1 2 1 ,0 and on the right wall a y xay 2 2 sin1 2 1 ,0 0,1)iii on the inside circular cylinder circumference. waviness =a/w, and a is the aspect ratio = h/w =1.5= 4d, w is the average width of the enclosure. 3. numerical solution and validation 3.1 software overview the non-dimensional equations system (equs.6-7) is to be solved numerically by mean of the software package flexpde professional version 5.0.20 3d. the flexpde is a scripted finite element model builder and numerical solver written by user (gunnar 2005). it performs the operations necessary to turn a description of a partial differential equations system into a finite element model, solve the system, and present graphical and tabular output of the results. it has no pre-defined problem domain or equation list, i.e. the domain geometry and the partial differential equations are totally achieved by the user. the flexpde is combined of several modules to provide a complete problem solving system, these are: a script editing module with syntax highlighting provides a full text editing facility and a graphical domain preview. a symbolic equation analyzer expands defined parameters and relations, performs spatial differentiation, and symbolically applies integration by parts to reduce second order terms to create symbolic galerkin equations. it then symbolically differentiates these equations to form the jacobian coupling matrix. a mesh generation module constructs a triangular or tetrahedral finite element mesh over a two or three-dimensional problem domain. in two dimensions, an arbitrary domain is filled with an unstructured triangular mesh. in three-dimensional problems, an arbitrary twodimensional domain is extruded into the third dimension and cut by arbitrary dividing surfaces. the resulting three-dimensional figure is filled with an unstructured tetrahedral mesh a finite element numerical analysis module selects an appropriate solution scheme for steady-state, time-dependent or eigenvalue problems, with separate procedures for linear and nonlinear systems. the finite element basis may be either quadratic or cubic. an adaptive mesh refinement procedure measures the adequacy of the mesh and refines the mesh wherever the error is large. the system iterates the mesh refinement and solution until a user-defined error tolerance is achieved. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 a dynamic time step control procedure measures the curvature of the solution in time and adapts the time integration step to maintain accuracy. a graphical output module accepts arbitrary algebraic functions of the solution and plots contour, surface, vector or elevation plots. a data export module can write text reports in many formats, including simple tables, full finite element mesh data, cdf or tecplot compatible files. an example of customized graphical outputs is shown in figure 2 and the edited script of the present work is presented in appendix 1. the results are to be represented by stream lines, isotherms and local and average nusselt numbers. the contours plots are directly captured from the output screen but the data of nusselt number were exported to another grapher tool to be able of showing more than one curve in single plot. 3.2 software validation to check the validity of the present used software, and enhance the reliability of the obtained results, the average nusselt number along the perimeter of the inner cylinder nuav,i was evaluated at five grid densities and for three values of darcy modified rayleigh number ram. the grid density in this package is controlled by imposing a relative error together with a mesh refinement times. the relative error was varied from 10-2 to 10-6 and the mesh refinement times were left to be free. the results are presented in figure 3. it can be seen that at low ram, the results are slightly affected by the grid size. but at higher ram (ram>500), there is a noticeable sensitivity of the results to the grid size especially at ram=700. however, this figure indicates that when the relative error 10-4 i.e. higher grid density, the results of nuav,i are approximately fixed for all ram's. accordingly, a relative error of 10-4 was chosen in this study as a compromise between the accuracy of the results and the time consumed in each run. some cases take a run time of about 900 seconds. the girded domain of 10-4 relative error is shown in figure 4 which indicates that flexpde is adaptively refining the mesh wherever it detects that there are strong curvature in the solution domain. 4. results and discussion to enhance the validation of the present numerical results, a comparison with other works was conducted for two different physical domains. these two domains have flat walls ( =0) with (a=1) i.e. square enclosure, and filled with fluid-saturated porous media according to darcian assumption. the first case is that of (barletta and lazzari 2005) where there exist an internal concentric circular cylinder subjected to a uniform heat flux while the flat walls are kept isothermal at =0. the results are presented in table1 by average nusselt number on the internal circumference. the second case which was investigated in more than one published works is free of any internal body and adiabatic horizontal walls and isothermal (but with different temperature) vertical walls (misirlioglu et al 2005). the results are presented in table2 by average nusselt number on the isothermal walls. it seen that there is a very good agreement between the present results of nuav,i and the two different cases. therefore, the confidence in using the present numerical package is highly enhanced. the effects of darcy modified rayleigh number ram isotherms, and local and average nusselt numbers. the examined ranges of ram is from 100 to 1000; : 0, 0.1, 0.25, 0.35; and : 0.45, 0.55, 0.75 (enclosure center), 0.95, and 1.05. the results are figured and gathered in the following two categories. 4.1 stream and isothermal lines figure 5 shows the streamlines inside the enclosure of =0.1 and ram=100 (upper row) and ram=1000 (lower row) for three different values of (1.05, 0.75 and 0.45). in all these cases, a double symmetric circulation cells with different directions is noticed. the clockwise direction is denoted by negative sign of stream function while the anticlockwise one is denoted by the positive sign. however, the double circulation cells are formed as the hot fluid moves up from the al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 surroundings of inner cylinder towards the adiabatic upper flat wall and turn to the neighboring wavy wall (in both sides) where it mixes with cold fluid stream falling down along the wavy (cold) walls. thus, the center of these circulation cells is over the inner cylinder center in all these subfigures. the offset between the two centers increases wi resulting in a more strength circulation occupying large space of enclosure as in the case of =0.45 where the fluid circulation covers most of the enclosure space. when ram is increased, the strength of stream function is increased also where its value at ram=1000 is about five times that when ram=100. this is due the domination of the convection over conduction which in turn leads to a good circulation inside the enclosure figure 6 shows the isotherms for the previous case ( =0.1, ram=100, 1000, =1.05, 0.75, 0.45). at low ram(=100), the upper row of figure 6, a parallel lines are observed around the inner cylinder except at its upper portion where a plume like distribution is observed and this distribution is grow when the inner cylinder is lowered. it is seen that the temperature gradient between the inner cylinder surface and the porous media is minimum at the source regime of the plume like distribution. for higher ram and especially at ram=1000, as presented in the lower row of figure 6, the isothermal lines take the shape of tangent function or what is called climbing sine function (± sin x ± x). the plume like distribution at the upper portion of the inner cylinder is sharper here and its regime is limited. this complex distribution of isotherms is due to the enhanced convection. it is seen that lowering the position of the inner cylinder also enhance the convection heat transfer due to the increased contribution space of the enclosure filled with porous medium. generally, a thermal boundary layer appears on the upper part of the wavy walls. this thermal boundary layer becomes thinner at high ram as it appears from figure 6. the parameters of figure 7 are same as that of figures 5 and 6 except =0.35. there is no specified difference between the distribution and the magnitude of stream function except in the case of ram=100 and =1.05 where the center of the double circulation cells is below that of the inner cylinder. this because the geometry of the enclosure at =0.35, where the flat adiabatic wall length is significantly small and the upper (and lower) part of the wavy cold walls is semihorizontal which concentrates the faller cold stream far away from the inner cylinder. on the other hand, the isotherms of figure 8 which are refer to the same previous case of =0.35 could be classified into two patterns. in the first pattern ram=100 (upper row of figure 8), the isotherm behavior is similar to that when =0.1 but the temperature is less at the upper part of the enclosure. while the isotherms of ram=1000 (lower row of figure 8) behaves exactly as same as that of =0.1. 4.2 variations of nusselt number the local nusselt number is examined along the circumference of the inner cylinder and the right wavy wall. figure 9 illustrates the distribution of the local nusselt number along the circumference of the inner cylinder for three ram (100, 500, 1000) and three values of (1.05, 0.75, 0.45) and for =0.25. for all these six parameter combinations, the distribution of nusselt number is symmetric (with one peak) about the vertical line x=0 which appears in figures at si=0.5. the values of nui increase with increasing ram due to the added heat transfer which is seen clearly from the stronger circulation at high ram shown in figures 5 and 7. the peaks appear at si=0.5 i.e. at the lowest point of the circumference because of the temperature gradient here is maximum as it previously clarified on the isothermal lines of figures 6 and 8. it is seen also that the curvature of the two sides of the bell shaped distribution of nui diminishes with lowering the inner cylinder position. it becomes completely straight line at =0.45, thus resulting in an increase in the overall heat transfer (the area under curves). the virtue of this increase in heat transfer refers to that at cylinder. finally the peak of nui distribution of the case =0.45 and ram=100 becomes more flat along the segment 0.25<si<0.75. this is because the uniform temperature gradient along this segment as it appears from isotherms of figures 6 and 8. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 10 shows the variation of nusselt number along the right wavy wall for the same parameters of figure 9. generally, the values of local nusselt number increases monotonically along the wavy wall from bottom to top depending on the inner cylinder position. when the cylinder is at the upper position =1.05, the heat may transfer across only one-half of the wavy wall as seen in figure 10. more length of wavy wall co lowered as seen from figures 10 b and c. thus, increasing the area under curves (averaged nusselt number) results in an improved heat transfer through the enclosure. the increase of local nusselt number with ram is attributed to the good circulation at higher ram values as explained previously in the lower rows of figure 5 and 7. also at higher ram, the increase of nusselt number values becomes steeper near the upper part of the wavy walls. this is due to the high temperature gradient between the wavy wall and the fluid inside the porous enclosure as shown previously in figures 6 and 8. it is convenient to mention here that the variation of local nusselt number along the left wavy wall is not shown because it is the mirror of that of the right wavy wall. to imagine the effect of ram circumference-averaged nusselt number is graphed with ram in figures 11 and 12. figure 11 shows the effect of ram variation of nuav,i is as expected; increases with ram lowered, this effect clearly appears in figure 11 a, b and c. for example, at ram=1000, an increase in nuav,i of about 19% is gained when is lowered from 1.05 to 0.45. the lowest two positions of inner cylinder exhibit less variation than other positions. this is due to the variation of convection dominance with the inner cylinder position. the implication of an insight to figures 11 a, b, and c alternatively, figure 12 shows the effect of ram nuav,i nuav,i can be sensed in few situations of this study but is generally is very small. when the inner cylinder is at highest position ( =1.05), the effect of is maximum (figure 12a). this is because that the surface of inner cylinder is closest to the wavy surface and in this portion of enclosure the concentrated stream function and temperature gradient is maximum due to convection. a waviness value of =0.25 exhibit more improvement of heat transfer. this scenario is enhanced in figure12c where the inner cylinder is at lowest position ( =0.45). here when ram=400, the effect of is squeezed due to the dominance of convection in most of the enclosure. figure 12b implies to no sensed variation of nuav,i figures 12b and c show an inverse figures 12a-c can be specified from the two ends of each curve, where they have higher values of nuav,i 5. conclusions natural convection heat transfer and fluid flow inside a fluid-saturated porous media wavy enclosure heated by an internal circular cylinder was investigated basing on darcian assumptions. the appliance of investigation was galerkin finite-element method implemented through the software package (flexpde). the effect of three dimensionless parameters was studied namely; darcy modified rayleigh number, inner cylinder position, and waviness of wavy walls. the results led us to the following conclusions i-for any values of inner cylinder position and wall waviness, the heat transfer is an increasing function of darcy modified rayleigh number. iihigher heat transfer is obtained when the inner cylinder is positioned below the mid enclosure height and whatever the wall waviness be. iiilittle influence of wall waviness on heat transfer when the inner cylinder is positioned above the mid-enclosure height, otherwise, there is no influence of wall waviness. references adjlout l., imine o., azzi a., and belkadi m., 2002, "laminar natural convection in an inclined cavity with a wavy wall" international journal of heat and mass transfer vol. 45 2141 2152. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 barletta a., and lazzari s., 2005, "2d free convection in a porous cavity heated by an internal circular boundary" excerpt from the proceedings of the comsol metaphysics user's conference stockholm basak t, roy s., singh a., and pop i., 2009, "finite element simulation of natural convection flow in a trapezoidal enclosure filled with porous medium due to uniform and non-uniform heating" international journal of heat and mass transfer vol. 52 70 78. basak t, roy s., singh a. and balakrishnan a.r., 2009, " natural convection flows in porous trapezoidal enclosures with various inclination angles" international journal of heat and mass transfer vol.52 4612 4623. baytas a.c. and pop i., 1999, "free convection in oblique enclosures filled with a porous medium" int. j. heat mass transfer vol.42 pp1047 1057. baytas a.c. and pop i. 2002, "free convection in a square porous cavity using a thermal non equilibrium model" int. j. therm. sci. vol. 41 861 870. braga e. j., marcelo j.s. de lemos, 2009, "laminar and turbulent free convection in a composite enclosure" international journal of heat and mass transfer vol. 52 588 596. clifford k., ho stephen and w. webb, 2006 "gas transport in porous media" springer. goyeau b., songbe j.p., and gobin d., 1996, "numerical study of double-diffusive natural convection in a porous cavity using the darcy-brinkman formulation" int. j. heat mass transfer vol.39 1363 1378. gross r.j., bear m.r. and hickox c.e., 1986, "the application of flux-corrected transport (fct) to high rayleigh number natural convection in a porous medium" in: proc. 8th int. heat transfer conf., san francisco, ca. gunnar b., 2005, "fields of physics by finite element analysis using flexpde" by gb publishing and gunnar backstrom malmo, sweden ingham d. b. and pop i., 2002, "transport phenomena in porous media ii" first edition elsevier science, khaled a.-r.a. and vafai k. 2003, "the role of porous media in modeling flow and heat transfer in biological tissues" international journal of heat and mass transfer vol.46 4989 5003. khanafer k., al-azmi b. and marafie a., pop i., 2009, "non-darcian effects on natural convection heat transfer in a wavy porous enclosure" international journal of heat and mass transfer vol.52 1887 1896. kulasiri d. and verwoerd w., 2002, "stochastic dynamics modeling solute transport in porous media" first edition elsevier science b.v. kumar b.v. r., and shalini, 2003, "free convection in a non-darcian wavy porous enclosure" international journal of engineering science vol.41 1827 1848. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 mahmud s, kumar p., hyder n. and sadrul islam a.k.m., 2002, "free convection in an enclosure with vertical wavy walls" international journal of thermal science vol.41 440 446. mahmud s., sadrul islam a.k.m., 2003, "laminar free convection and entropy generation inside an inclined wavy enclosure, international journal of thermal sciences vol.42 1003 1012. mahmud s. frase and r. a., 2004, "free convection and entropy generation inside a vertical in phase wavy cavity" int. comm., heat mass transfer, vol. 31, no. 4, pp 455-466. manole d.m., lage j.l. 1992, "numerical benchmark results for natural convection in a porous medium cavity" in: heat and mass transfer in porous media asme conf. htd-216, pp. 55 -60. marafie a. and vafai k., 2001, "analysis on non-darcain effect on temperature differentials in porous media" international journal of heat and mass transfer vol.44 4401 4411. misirlioglu a., baytas a.c., and pop i., 2005, "free convection in a wavy cavity filled with a porous medium" international journal of heat and mass transfer vol. 48 1840 1850. moya s.l., ramos e., and sen m., 1987, "numerical study of natural convection in a tilted rectangular porous material" int. j. heat mass transfer vol.30 pp 741 756. nield d.a. and bejan a., 2006, "convection in porous media" third edition, springer science + business media, inc., new york.. oztop h. f., "natural convection in partially cooled and inclined porous rectangular enclosures" international journal of thermal sciences vol.46 149 156 2007 sultana z., and hyder n., 2007, "non-darcy free convection inside a wavy enclosure" international communications in heat and mass transfer vol.34 136 146. varol y, oztop h, f., and varol a., 2006, "free convection in porous media filled right-angle triangular enclosures" international communications in heat and mass transfer vol.33 1190 1197. varol y, oztop h. f., and varol a, 2007, "effects of thin fin on natural convection in porous triangular enclosures" international journal of thermal sciences vol.46 1033 1045. varol y, oztop h. f., and yilmaz t., 2007, "two-dimensional natural convection in a porous triangular enclosure with a square body" international communications in heat and mass transfer vol.34 238 247. varol y, oztop h. f. and pop i., 2008, "numerical analysis of natural convection for a porous rectangular enclosure with sinusoidally varying temperature profile on the bottom wall" international communications in heat and mass transfer vol.35 56 64. varol y, oztop h. f., and pop i., 2009, "natural convection in right-angle porous trapezoidal enclosure partially cooled from inclined wall," international communications in heat and mass transfer vol. 36 6 15. varol y, oztop h. f., and pop i., 2010, "maximum density effects on buoyancy-driven convection in a porous trapezoidal cavity" international communications in heat and mass transfer vol. 37 401 409. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 zhao f., liu d., and tang g., 2008, "natural convection in a porous enclosure with a partial heating and salting element" international journal of thermal sciences vol.47 569 583. table 1 values of averaged nusselt number along the circumference of internal cylinder-comparision with the case of (barletta and lazzari 2005) l/d 2 4 ram 300 1000 3000 300 1000 3000 barleta and lazzari 2005 5.791 7.786 11.17 6.951 10.25 15.07 present 5.791 7.785 11.165 6.952 10.246 15.065 table 2 values of averaged nusselt number on the isothermal walls of square cavitycomparision with the case of (misirlioglu et al 2005) and other references cited in it. authors ram=10 ram=100 ram=1000 misirlioglu et al 2005 1.19 3.05 13.15 moya 1987 1.065 2.801 baytas and pop 1999 1.079 3.16 14.06 present 1.0795 3.135 13.915 fig.1 physical domain of the enclosure wa h x y =1 =0 0 =0 0 =0 00 n 00 n d si sr al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.2 an example of customized graphical results fig.4 distribution of grids (10806 nodes) over the domain of ram=100, =0.25, =0.75 fig.3 variation of average nusselt number with the relative error (number of grids) =0.25, =0.75 1x10-2 1x10-3 1x10-4 1x10-5 1x10-6 relative error 12 14 16 18 20 22 24 26 n u a v, i ram=300 ram=500 ram=700 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.5 streamlines for =0.1, and ram=100 (upper row), 1000 (lower row), =1.05 (left column), 0.75(middle column) and 0.45 (right column) fig.6 isotherms for =0.1, and ram=100 (upper row), 1000 (lower row), =1.05 (left column), 0.75(middle column) and 0.45 (right column) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.7 streamlines for =0.35, and ram=100 (upper row), 1000 (lower row), =1.05 (left column), 0.75(middle column) and 0.45 (right column) fig.8 isotherms for =0.35, and ram=100 (upper row), 1000 (lower row), =1.05 (left column), 0.75(middle column) and 0.45 (right column) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 si 0 5 10 15 20 25 30 35 40 45 50 55 n u i ram=100 ram=500 ram=1000 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 si 0 5 10 15 20 25 30 35 40 45 50 55 n u i ram=100 ram=500 ram=1000 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 si 0 5 10 15 20 25 30 35 40 45 50 55 n u i ram=100 ram=500 ram=1000 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 sr 0 10 20 30 40 50 60 70 80 90 100 110 120 n u r ram=100 ram=500 ram=1000 fig.9 variation of local nusselt number along the inner cylinder cicumference for =0.25 and and (a) =1.05, (b) =0.75, (c) =0.45 fig.10 variation of local nusselt number along the right wavy wall for =0.25 and (a) =1.05,(b) =0.75,(c) =0.45 (a) (a) (b) (b) (c)(c) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 sr 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 n u r ram=100 ram=500 ram=1000 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 sr 0 10 20 30 40 50 60 70 80 90 100 110 120 n u r ram=100 ram=500 ram=1000 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 200 400 600 800 1000 ram 5 10 15 20 25 n u a v, i =1.05 =0.95 =0.75 =0.55 =0.45 0 200 400 600 800 1000 ram 5 10 15 20 25 n u a v, i =1.05 =0.95 =0.75 =0.55 =0.45 0 200 400 600 800 1000 ram 5 10 15 20 25 n u a v, i =1.05 =0.95 =0.75 =0.55 =0.45 0 200 400 600 800 1000 ram 6 8 10 12 14 16 18 20 22 n u a v, i =0 =0.1 =0.25 =0.35 0 200 400 600 800 1000 ram 6 8 10 12 14 16 18 20 22 24 n u a v, i =0 =0.1 =0.25 =0.35 0 200 400 600 800 1000 ram 6 8 10 12 14 16 18 20 22 24 26 n u a v, i =0 =0.1 =0.25 =0.35 fig.12 variation of average nusselt number with darcy for (a) =1.05, (b) =0.7 5, (c) =0.45 fig.11 variation of average nusselt number with darcy for (a) =0.1, (b) =0.25, (c) =0.35 (c) (c) (b) (a) (a) (b) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 appendix 1 (the edited script) title 'wavy enclosure heated by inner cylinder' coordinates cartesian2 variables epsi theta select errlim=1e-5 textsize=30 !black=on paintgrid=off definitions ra=100 ar=1.5 a=.25 xc=0 cy=0.0 yc=ar/2-cy dc= 0.25*ar equations epsi:div(grad(epsi))+ra*dx(theta)=0 theta : dy(epsi)*dx(theta)-dx(epsi)*dy(theta)-div(grad(theta))=0 boundaries region 1 start(0,0) natural (theta)=0 value(epsi)=0 line to (0.5-a,0) value(epsi)=0 value(theta)=0 line to (0.5-a,0) #include 'sir.txt' natural (theta)=0 value(epsi)=0 line to (a-0.5,ar) value(epsi)=0 value(theta)=0 line to (a-0.5,ar) #include 'sil.txt' line to close start (xc,yc+dc/2) value(epsi)=0 value(theta)=1arc(center=xc,yc) angle=360 feature start 'left side' (0.5-a,0) line to (0.5-a,0) #include 'sir.txt' start 'right side' (a-0.5,ar) line to (a-0.5,ar) #include 'sil.txt' start 'inner rod' (xc,yc+dc/2)arc(center=xc,yc)angle=360 plots elevation (-normal(grad(theta))) on 'left side' export format "#d#b#1" file="l.txt" elevation (-normal(grad(theta))) on 'right side' export format "#d#b#1" file="r.txt" elevation (-normal(grad(theta)))on 'inner rod' export format "#d#b#1" file="i.txt" contour(theta) contour(epsi) grid(x,y) report((line_integral(normal(grad(theta)),'left side'))) as "avnus" report((line_integral(-normal(grad(theta)),'right side'))) as "avnus" report((line_integral(-normal(grad(theta)),'inner rod'))) as "avnus" end note: sir and sil are text files represent the wavy walls edited from other two separated scripts: title 'right wall' coordinates cartesian1 definitions ar=1.5 a = 0.25 u =(0.5-a)+a*(1-sin ((pi/2)+2*pi*x/ar)) boundaries region 1 start(0) line (ar) plots elevation(u) from (0) to (ar) points =5 export format "to (#1,#x)" file="sir.txt" end title 'left wall' coordinates cartesian1 definitions ar=1.50 a = 0.25 u =-(0.5-a)-a*(1-sin ((pi/2)+2*pi*x/ar)) boundaries region 1 start(ar) line (0) plots elevation(u) from (ar) to (0) points =5 export format "to (#1,#x)" file="sil.txt" end template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 43 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. تأثير استعمال نسب مختلفة من خرسانة التبليط االسفلتي المعاد تدويرها على خصائص الخلطات االسفلتية )االسفلت غير المعدل و االسفلت المعدل( م.م.محمد عزيز حميد الشيباني , بغداد , العراقوزارة التربٌة email: mohammedalshaybani@yahoo.com received on 17 january 2017 accepted on 13 april 2017 بصورة عامة وبسبب االستنزاف المستمر للموارد الطبٌعٌة فً العراق برزت الحاجة الى العدٌد من الدراسات والتً :الملخص ك بالتوجه الستخدام مواد معاد تدوٌرها مما قد ٌؤدي الى تقلٌل الكلفة والحفاظ على البٌئة. تروم الى تقلٌل االستنزاف وذل وذلك لتحسٌن االداء وزٌارة العمر الخدمً للتبلٌط وتقلٌل االضرار (rr) وباإلمكان استخدام المضافات مثل المطاط المحسن وكذلك دراسة تأثٌر استخدام (rap) ام المواد المعاد تدوٌرهاالمبكرة. الغرض الرئٌسً من هذه الدراسة هو دراسة تأثٌر استخد لتحقٌق هدف الدراسة, فً الجزء العملً (rap) على خصائص الخلطة االسفلتٌة وتحدٌد النسبة المثلى من ال (rr) المضاف لنماذج %( من وزن الركام عند عملٌة تحضٌر ا01%, 01%, 01%, 01%, 01هً ) (rap) تم استخدام نسب مختلفة من ( باالعتماد على دراسة سابقة وتم تقٌٌم أداء الخلطات اإلسفلتٌة باستخدام 00وبنسبة )% (rr) باإلضافة الى استخدام المضاف من هذه الدراسة نستنتج ان .(rap) اختبار مارشال و اختبار الشد غٌر المباشر وتمت مقارنة نتائج استخدام نسب مختلفة من ال د اقصى فً الخلطات ذات االسفلت االعتٌادي من الممكن ان تلبً متطلبات المواصفات الخاصة كح (01rapاستخدام )% لكً نضمن اداء افضل للتبلٌط االسفلتً, اما فً حالة استخدام (01rapبالطبقة السطحٌة ولكن من االفضل استخدام نسبة )% (01rap( حٌث ان نسبة ال )% 01الى% 01من )% (rap) فتزداد نسبة استخدام ال (00rrاالسفلت المعدل بال )% لكً نضمن درجة اداء افضل للتبلٌط. واخٌرا اوصت (01rapتحقق متطلبات المواصفة ولكن ٌفضل استخدام نسبة ال )% .الدراسة بأجراء تجارب على نطاق واسع وان تأخذ فً االعتبار المزٌد من حاالت خلط المكونات وبظروف مختلفة السفلت, التبلٌط االسفلتً المعاد تدوٌره, الثبات, مقاومة الشد غٌر المباشر, المطاط المحسن.ا الكلمات الدالة: influence of using a various percentages of reclaimed asphalt concrete pavement on properties of mixture asphalt (unmodify asphalt and modify asphalt) mohammed aziz hameed al-shaybani, ministry of education, baghdad. iraq email: mohammedalshaybani@yahoo.com abstract: in general, because of the constant depletion of natural resources in iraq, there was a need to numerous studies that may lead to reduce the use of these resources through reuse recycling process which could lead to reduced costs and preservation of the mailto:mohammedalshaybani@yahoo.com mailto:mohammedalshaybani@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 44 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. environment. it is possible to use additives such as reclaimed rubber (rr) to improve the performance and extend service life and reduce early distress. the main purpose of this study was to study the effect of using the reclaimed asphalt pavement (rap) and also study the effect of using the additive (rr) on the asphalt mixture properties and determine the optimum ratio of the (rap) to achieve the objective of the study. in practical part was used different percentages of (rap) is (10%, 20%, 30%, 40%, 50%) by weight of aggregate when preparing models process as well as using the additive (rr) and rate (15%), depending on a previous study. the performance of asphalt mixtures is evaluated by using marshall test and indirect tensile test the results were compared with using different percentages of (rap). results of the study, we can say that the use of (% 20rap) as a maximum percentage in unmodify asphalt mixtur course the specifications requirements of the surface layer, but it's best to use the percentage (10%rap) in order to ensure better performance, when use a modified asphalt with percentage (%15rr) the increased (rap) from (20% to 30%) as the percentage of (30%rap) achieved the specification requirements but preferred to use the ratio of (20%rap) in order to ensure the degree of better performance for paving. finally, the study recommended to conduct a large scale experiment to take into consideration more cases of mixing components and conditions.. keywords: asphalt, reclaimed asphalt pavement, stability, indirect tensile strength, reclaimed rubber. المقدمـــــــــة. 1 لموارد تعد مشارٌع انشاء الطرق من المشارٌع المهمة فً اغلب دول العالم ومنها العراق وذات كلفة انشائٌة مرتفعة وفً ظل االستنزاف المخٌف ل دٌة وتقلٌل استخدام الموارد الطبٌعٌة للمحافظة على الطبٌعٌة والظروف االقتصادٌة الصعبة التً ٌعانً منها البلد لذلك برزة الحاجة الى اٌجاد حلول اقتصا المستخدم منها البٌئة عن طرٌق العدٌد من البحوث والدراسات فً هذا المجال المهم اما عن طرٌق تقلٌل استخدام هذه الموارد او العمل على اعادة تدوٌر استثنائٌة وخاصة فً العراق لما ٌعانٌه البلد من ازمات اقتصادٌة وبسبب وجعله صالح لالستخدام مرة اخرى ومن المالحظ ان هذا الموضوع ٌأخذ اهمٌة ً القدٌمة او هبوط اسعار النفط فً اآلونة االخٌرة والحروب المستمرة وتوفر كم هائل من مخلفات البناء والطرق وغٌرها والناتجة عن طرٌق هدم المبان نتٌجة الحروب, لذلك من المهم اٌجاد حلول وبدائل ومن هذه الحلول امكانٌة اعادة تدوٌر ما ٌقارب قشط تبلٌط الطرق القدٌمة او المبانً و الطرق المدمرة %( من هذه المخلفات واستخدامها مرة اخرى واهم هذه المخلفات هً المخلفات الخرسانٌة, وفً العقدٌن الماضٌٌن زاد استخدام التبلٌط 01-%50من ) وخاصة فً الدول المتقدمة كالوالٌات المتحدة االمرٌكٌة حٌث reclaimed asphalt pavement (rap)))تدوٌراالسفلتً الناتج من عملٌة اعادة ال (%( من كمٌات التبلٌط األسفلتً 01( ملٌون طن من التبلٌط االسفلتً المستصلح سنوٌا ألغراض إعادة التدوٌر وهً عبارة عن 00ٌتم استخدام حوالً ) 01(, تم إنتاج حوالً ))0000وكذلك, فً عام ) .( (holtz and eighmy ,2000 تم جمعها من قشط تبلٌط الطرق القدٌمةالذي ٌتم اعادة تدوٌره التً (%( من إجمالً إنتاج الخلطات الخرسانٌة المستخدمة فً 01ملٌون طن من خلطات الخرسانٌة االسفلتٌة المعاد تدوٌرها فً الٌابان, والتً تمثل حوالً فً العراق ٌخلط ناتج قشط التبلٌط فً تربة القاعدة لتزٌد من قوة تحملها, باإلضافة إلى استخدامه .(ikeda and kimura, 1997) انشاء الطرق لمخلفات كطبقة اكساء وبشكل مؤقت الماكن توقف المركبات والطرق الترابٌة فً المناطق الرٌفٌة للحد من تطاٌر األتربة, ان عملٌة إعادة تدوٌر ا 0000تحددها بعض المحددات من الناحٌة االقتصادٌة لذلك ٌجب األخذ بنظر االعتبار اهمٌة القٌمة االقتصادٌة لعملٌة اعادة التدوٌر), الخرسانٌة jeffrey). ٌة للطرق ٌجب توفر التقنٌات الالزمة إلعادة التدوٌر باإلضافة إلى خواص المادة المراد اعاد تدوٌرها مع االعتماد على المواصفات العراق حٌث من الممكن إعادة تدوٌر مخلفات الخرسانٌة بإحدى الطرٌقتٌن, .scrb, 2004)) والجسور والبقاء ضمن حدود المواصفات للطبقات المختلفة حتاج بالضرورة إلى الطرٌقة األولى: هً استخدام ناتج عملٌة التدوٌر كركام خشن وركام ناعم واعادة استخدامه فً انتاج خرسانة جدٌدة, وهذه العملٌة ت ناتج عملٌة التدوٌر تكسٌره بكسارات حسب حالة المخلفات الخرسانة و من ثّم استخدامه فً عملٌة انتاج الخرسانة الجدٌدة. أما الطرٌقة الثانٌة: هً استخدام عدٌدة من عملٌة تدوٌر المخلفات هناك فوائد .(besseche et al, 2009) فً انشاء طبقة أساس الطرق كونه أفضل من استعمال الحصى الخابط -:اهما ,(copeland and bukowski, 2001) الخرسانٌة واعادة استخدامها مرة اخرى فً مشارٌع متعددة .الحد او التقلٌل من استخدام الموارد الطبٌعٌة تقلل من استنزافها -ا .المنفعة االقتصادٌة من حٌث تقلٌل كلفة االنتاج-ب .ى لالستثمار عن طرٌق انشاء معامل إلعادة تدوٌر هذه المخلفات والمحافظة على البٌئةتوفٌر مصادر اخر -ج al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 45 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. بيان المشكلة ودافع الدراسة . 2 أنشاء بسبب الحاجة المتزاٌدة لشبكات الطرق فً اغلب دول العالم منها العراق واغلب دول العالم حٌث هناك مشارٌع متعددة لتوسٌع شبكة الطرق ب لهذا تحتاج الطرق بصور عامة الى صٌانة دورٌة ضرورٌة للحفاظ على كفاءة الشبكة الستٌعاب حركة الحجوم المرورٌة بانسٌابٌه وامان. طرق جدٌدة, ء تخصص ألنشانظرا لالزمة االقتصادٌة التً ٌعانً منها البلد فً الوقت الحالً واحتمال استمرارها لفترة قد تصل الى سنوات ولعدم وجود اموال كافٌة موارد الطبٌعٌة وصٌانة الطرق بصورة مستمرة وارتفاع اسعار الركام الجٌد والذي ٌمثل النسبة االكبر فً انتاج الخرسانة االسفلتٌة واالستنزاف الحاد لل تلفة العدٌد من االسالٌب الجٌدة لذلك وجد من الضروري البحث عن وسائل جدٌدة للصٌانة اقل تكلفة وصدٌقة للبٌئة, ظهرت فً العدٌد من دول العالم المخ رق تحقٌق هذا الحدٌثة لصٌانة الطرق بواسطة استخدام تقنٌات اعادة تدوٌر التبلٌط القدٌم المتضرر, بحٌث قامت كثٌر من الهٌئات المتخصصة فً مجال الط ومن ثم اعادة استخدامها بإضافتها الى المزٌج الغرض عن طرٌق اعادة استخدام التبلٌط االسفلتً القدٌم مرة اخرى بعد عملٌة الطحن بواسطة معدات خاصة استخدام المواد الجدٌد وبنسب مزج مختلفة وٌتم ذلك من خالل اعداد برنامج عمل مختبري ٌشمل المقارنة بٌن استخدام الخلطات االسفلتٌة االعتٌادٌة بدون لتً تحتوي على نسب مختلفة من المواد المعاد تدوٌرها واالسفلت المعدل الناتجة من عملٌة اعادة التدوٌر وبدون استخدام االسفلت المعدل مع الخلطات ا وتتم المقارنة باالعتماد على النتائج المختبرٌة. اهداف الدراســـــــــة. 3 -:االهداف الرئٌسة لهذه الدراسة هً الخلطة االسفلتٌة عن طرٌق اجراء الفحوصات المختبرٌة اي فً عملٌة انشاء الطرق وتحدٌد النسبة المثلى التً تضاف الى (rap) التحقق من استخدام • .فحص مارشال وفحص مقاومة الشد غٌر المباشر ( فً انتاج rapدراسة تأثٌر استخدام المواد المضافة اي استخدام االسفلت المعدل على خصائص خلطة الخرسانة االسفلتٌة وتأثٌره على محتوى ال) • الخلطات الجدٌدة. لمستخدمـــــــــةمواد ا. ال4 (aggregates) الركام 1.4 (coarse aggregates) فً العراق هناك مصادر عدٌدة للركام المستخدم فً انشاء الطرق, اما فً هذه الدراسة تم استخدم الركام الخشن مت عملٌة اعادة نخله واعادة خلطه لكً ٌلبً الذي تم الحصول علٌه من معامل الحجارة فً محافظة النجف وقد ت (fine aggregates) والركام الناعم لمعظم أجزاء شبكة الطرق فً وسبب اختٌار هذه الطبقة هو أنها الطبقة السطحٌة (a) نوع (wearing coarse) التدرج المطلوب للطبقة السطحٌة لسطحٌة لذا ٌتوقع أن ٌكون أكثر الطلب على هذا النوع من والتً تتعرض دائماً ألعمال الصٌانة المتمثلة غالباً فً قشط وإعادة فرش نفس الطبقة ا ق العرا ( ٌوضح الخواص الفٌزٌائٌة للركام 0الجدول رقم ) .scrb, 2004))الخلطات اإلسفلتٌة وٌجب ان تكون ضمن المواصفات العراقٌة للطرق والجسور ( ٌوضح التدرج الحبٌبً للركام0, اما الجدول رقم )المستعمل فً الدراسة (physical properties of aggregates) الخشن والركام الناعم (aggregate gradation). ( ٌوضح الخصائص الفٌزٌائٌة للركام.0جدول رقم ) الركام الخشن الركام الناعم رقم المواصفة لل ( astm) الخاصٌة 2.62 2.53 c-127 c-128 الوزن النوعً الكلً (bulk specific gravity) 2.68 2.66 c-127 c-128 apparent) الوزن النوعً الظاهري specific) gravity 2.81 3.15 c-127 c-128 نسبة امتصاص الماء )% water absorption) ---- 29 max 35% c-131 اختبار لوس انجلوس % wear (los angeles) ----94% d 5821 السطح الزاوي (angularity) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 46 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (.a( نوع )wearing coarse( ٌوضح تدرج الركام وحدود المواصفة للطبقة السطحٌة )0) جدول رقم (filler) المادة المالئة 2.4 ( 0د تم استخدامه من هذه المادة هو االسمنت البورتالندي الذي جلب من مناطق شمال العراق بالتحدٌد منطقة )طازلوجا(, الجدول رقم )نوع واح .ٌوضح الخصائص الفٌزٌائٌة لهذه المادة (.filler( ٌوضح الخصائص الفٌزٌائٌة للمادة المالئة ال)0جدول رقم ) (asphalt) األسفلت 3.4 penetration grade) ودرجة اختراق (pg 70-10) (performance grade) تم استخدام نوع واحد من االسفلت ذو درجة اداء .( ٌوضح الخصائص الفٌزٌائٌة لهذا النوع من االسفلت الذي استخدم فً البحث0تم جلبه من مصفى الدورة, الجدول رقم ) ((40-50) (reclaimed rubber (rr)) المطاط المحسن 4.4 المستعمل كمادة مضافة لتحسٌن خواص االسفلت من معمل اطارات النجف وهً عبارة عن مادة حبٌبٌة (rr) تم الحصول على المطاط المحسن ا لتحسٌن خواصها ناتجة من عملٌة سحق االطارات القدٌمة واضافة بعض المواد المطاطٌة له (1.16) (specific gravity) سوداء ذات كثافة نوعٌة وباالعتماد على دراسة (rr%15) وهذا النوع ٌستخدم فً عملٌة اعادة التدوٌر إلنتاج اطارات السٌارات, استخدمت فً هذه الدراسة نسبة واحدة هً ذه بالطرٌقة مع االسفلت بواسطة استخدام جهاز خلط خاص وتعرف طرٌقة الخلط ه (rr) تمت عملٌة خلط المضاف .(al-bana’a, 2009) سابقة (rr)حٌث تتم عملٌة خلط االسفلت مع المضاف قبل عملٌة تحضٌر الخلطة االسفلتٌة وتتم هذه العملٌة بإضافة ال (wet adding method) الرطبة ,c -190°c), (al-dubabe°( دورة فً الدقٌقة الواحدة( عند درجة حرارة تتحدد من )060الى االسفلت وٌخلط المزٌج وبسرعة ال تقل عن 1996011) (scrb)المواصفات حسب ال (r9/2003) االسمنت البورتالندي الخاصٌة الوزن النوعً 3.13 ------------- 200نسبة المار من منخل رقم 94 100 70 ( scrbالمواصفات القٌاسٌة حسب ال) (a) للطبقة السطحٌة نوع نسبة المار من مجموع وزن الركام والمادة المالئة سعة المنخل )ملم( 100 100 19 90-100 95 12.5 76-90 83 9.5 44-74 59 4.75 28-58 43 2.36 5-21 13 0.30 4-10 7 0.075 4 6 5 نسبة االسفلت من مجموع الوزن الكلً al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 47 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ( ٌوضح الخصائص الفٌزٌائٌة لإلسفلت.0جدول رقم ) reclaimed asphalt pavement (rap)))التبليط االسفلتي الناتج من اعادة التدوير 5.4 ( وهو عبارة عن مواد ناتجة من عملٌة قشط طبقة التبلٌط االسفلتً القدٌم وطحنها بواسطة معامل شٌدت لهذا الغرض فً العدٌد من rapال ) ( من اعمال قشط بعض الطرق فً محافظة كربالء وتم عملٌة طحنها واعادة نخلها و بتدرجات ذات حجوم حبٌبٌة rapالبلدان, تم جلب نموذج من ال) %( من 01%, 01%, 01%, 01%, 01( بنسب محددة هً )rapتلبً متطلبات التدرج المطلوب لهذه الدراسة, وتمت اضافة مادة ال)مختلفة لكً وزن الركام لدراسة تأثٌرها على خصائص الخلطة االسفلتٌة. الفحوصات المختبرية. 5 وصات التأهٌل للتعرف على خصائص المواد المختلفة المستخدمة فً هذا الدراسة تم تطبٌق نوعٌن من الفحوصات المختبرٌة, النوع االول هً فح ( والتً تبٌن ان هذه المواد صالحة ومقبولة االستخدام 0( الى رقم )0فً الدراسة ومدى مطابقتها للمواصفات المحددة وكما مبٌنه فً الجداول من رقم ) ئٌسة المستخدمة لتحدٌد وقٌاس خصائص الخلطة االسفلتٌة كفحص مارشالألعداد مزٌج الخلطة االسفلتٌة. اما النوع الثانً هً الفحوصات الر (marshall test) وفحص مقاومة الشد غٌر المباشر(indirect tensile strength test) ( 6( والجدول رقم )0وكما مبٌن فً الجدول رقم.) (marshall test) فحص مارشال 1.5 -astm d) قٌاسٌة بواسطة اعتماده من قبل الجمعٌة االمرٌكٌة الختبار المواد رقمتم اعتماد طرٌقة فحص مارشال كطرٌقة فحص وطرٌقة مارشال المذكورة تطبق فقط على مخلوطات التبلٌط االسفلتً على الساخن باستخدام االسفلت الصلب المعروف بدرجة الغرز او .(6927,2006 نها معتمدة فً العراق, استخدام فحص مارشال إلٌجاد المحتوى االمثل لإلسفلت المستعمل فً اللزوجة, وٌمكن اختٌار هذه الطرٌقة فً عملٌة التصمٌم أل (( من المحتوى االسفلتً لتحدٌد محتوى االسفلت االمثل0( ,)%0.0( ,)%0( )%0.0تحضٌر نماذج الخلطة االسفلتٌة, باعتماد اربع نسب هً))% (optimum asphalt contented (o.a.c)) الطبقة السطحٌة نوع واستخدمت (a) ًومن نتائج فحص مارشال وجد ان النسبة المثلى لإلسفلت ه وهذه النسبة تحقق متطلبات المواصفة الخاصة بال )الثبات, االنسٌاب ونسبة الفراغات (air voids% (0( والتً تقابل نسبة فراغات ))0%)% الشكل (scrb, 2004). الخاص بقبول تصمٌم الخلطة االسفلتٌة بطرٌقة مارشال (sorb) ورالهوائٌة( والمحدد من قبل الهٌئة العراقٌة للطرق والجس .( ٌبن العالقة بٌن الثبات, االنسٌاب ونسبة الفراغات الهوائٌة مع النسبة المئوٌة لإلسفلت إلٌجاد النسبة المثلى لإلسفلت0رقم ) (indirect tensile strength test (its)) فحص مقاومة الشد غير المباشر 2.5 ( ٌستعمل لقٌاس مدى مقاومة الخلطة االسفلتٌة لإلجهاد المسلط على العٌنة المختبرٌة حٌث ٌتم تعرٌض كل عٌنة الى itsاختبار مقاومة الشد غٌر المباشر ) م جهاز مارشال عنطرٌق تحوٌره ((. ٌمكن استخداashto, 2005انج فً الدقٌقة الواحدة 0( بمعدل تحمٌل )indirect tensionالشد غٌر المباشر) (scrb) مواصفات ال درجة (50-40االختراع) الفحص الوحدات (40-50) 47 1/10 mm 25)االختراق 0 c), 100 gm, 5sec) astm d-5 -------381 cst 135)اللزوجة الكٌنماتٌكٌة عند ال 0 c) astm-2170 >100 102 cm 25)قابلٌة السحب 0 c, 5 cm/min) astm d-113 min. 232 332 0 c درجة الومٌض بجهاز كلٌفالند المفتوح astm d-92 25)الوزن النوعً عند ) -----1.02 (1.01-1.05) 0 c astm d-70 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 48 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ملم(, وكل شرٌحة تحمٌل ٌجب ان تكون ذات طول 011ملم( وطول ) 00ألجراء هذا الفحص وذلك باستبدال رأس الجهاز بشرٌحتٌن معدنٌتٌن بعرض ) -( من المعادلة التالٌة :tensile strengthمساوي الرتفاع العٌنة, اجهادات الشد تتولد على المستوى الدائري لعٌنة االختبار, وٌتم حساب مقاومة الشد ) (.............................0) indirect tensile strength = -: حٌث p .)اقصى حمل )نٌوتن : t سمك عٌنة االختبار )ملم : .( d.)قطر عٌنة االختبار )ملم : ( وكذلك ٌبٌن تأثٌر استخدام االسفلت االعتٌادي rapارشال لنماذج الخلطات االسفلتٌة المتضمنة نسب مختلفة من )( ٌوضح نتائج اختبار م0جدول رقم ) (.rrالغٌر معدل واالسفلت المعدل بال) النموذج النسبة المئوٌة (rap)لل الثبات ( stability ) (kn) االنسٌاب (flow ) (mm) لهوائٌة نسبة الفراغات ا %( air void بالمخلوط ) bulk الكثافة الحقٌقة ) density) gm|cm³)) ل عد م ر غٌ ال ت فل س ال ا ت ذا ت طا خل ال ج اذ نم (c o n tr o l m ix tu re i s t h e c o n v e n ti o n a l m ix tu re w it h o u t m o d if ie r) 0 10.31 2.06 4.11 2.374 10 8.55 2.55 3.85 2.351 20 8.19 3.21 3.61 2.312 30 7.42 3.72 3.14 2.281 40 6.61 4.18 2.81 2.272 50 5.93 4.61 2.47 2.268 ب ل عد لم ا ت فل س ال ا ت ذا ت طا خل ال ج اذ نم ( r r % 1 5 ) (m o d if ie d a s p h a lt c o n c re te m ix tu re s w it h % 1 5 r r ) 0 12.81 2.29 4.19 2.331 10 10.52 2.75 3.97 2.298 20 9.49 3.32 3.77 2.271 30 8.53 3.83 3.21 2.238 40 7.04 4.42 2.92 2.226 50 6.27 5.05 2.79 2.221 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 49 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. وكذلك ٌبٌن تأثٌر (rap)لنماذج الخلطات االسفلتٌة المتضمنة نسب مختلفة من (its)( ٌوضح نتائج اختبار مقاومة الشد الغٌر مباشر6جدول رقم ) .(rr)الاستخدام االسفلت االعتٌادي الغٌر معدل واالسفلت المعدل ب . الفحوصات المختبرية نتائج ومناقشة 6 ( marshall test resultsنتائج فحص مارشال ) 1.6 ( ٌوضح نتائج فحص مارشال لنماذج خلطات الخرسانة االسفلتٌة.5رقم ) الجدول ( air voidsالفراغات الهوائية ) 1.1.6 الطةرق ان نسبة الفراغات الهواء هً من العوامل الهامة التً ٌجب مراعاتها عند تصمٌم خلطة الخرسانة اإلسفلتٌة. حددت المواصفات العامة لهٌئةة ( تحةدث 3%%( من الحجم الكلً للخلٌط, عندما تكون نسةبة الفراغةات الهوائٌةة اقةل مةن )5 -3% ( نسبة فراغات الهواء من )scrbوالجسور العراقٌة ) ( وخاصة عند ارتفةاع درجةات الحةرارة ممةا ٌةؤدي الةى انخفةاض محتةوى االسةفلت فةً التبلةٌط مةع مةرور الوقةت, وهةذا bleedingعملٌة النضح لإلسفلت ) ( ٌكةون التبلةٌط 5%(. ومةن ناحٌةة اخةرى ان زٌةادة نسةبة الفراغةات عةن ال )crackingسفلت فً التبلٌط قد ٌؤدي الى التشةققات )االنخفاض فً محتوى اال ( سةةٌقلل مةن نسةةبة الفراغةةات rap(, نالحةةظ ان زٌةةادة نسةبة )5ضةعٌف او غٌةةر مسةتقر. وبنةةاء علةى نتةةائج الفحةةص المختبةري الموضةةح فةً الجةةدول رقةم ) ت السفلت القدٌم الموجود فً المواد المعاد تدوٌرها والةذي ٌملةا المسةامات وبالتةالً تقةل نسةبة الفراغةات الهوائٌةة للخلةٌط, بالنسةبة للخلطةاالهوائٌة وذلك الن ا الةى (4.11%)تؤدي الةى تقلٌةل النسةبة المئوٌةة للفراغةات الهوائٌةة مةن (30%)الى (0%)( من rapذات االسفلت غٌر المعدل نالحظ ان زٌادة نسبة ) نسةبة الفراغةات ( اي خروج 2.81( نالحظ نقصان نسبة الفراغات الى )40%( الى )rapوعند االستمرار بزٌادة نسبة )( 25%( أي بحوالً )(%3.14 (. امةا بالنسةبة للخلطةات ذات5%الةى ) 3%) )مةن ( والخاصةة بالطبقةة السةطحٌة والتةً تحةدد scrbعةن المواصةفات المحةددة مةن قبةل ال ) الهوائٌةة ( (3.21% الةى (4.19%)تؤدي الى تقلٌل النسبة المئوٌة للفراغةات الهوائٌةة مةن (30%)الى (0%)( من rapاالسفلت المعدل نالحظ ان زٌادة نسبة ) عةن ٌةنسبة الفراغات الهوائ( اي خروج 2.92( نالحظ نقصان نسبة الفراغات الى )40%( الى )rapوعند االستمرار بزٌادة نسبة )( 23%أي بحوالً ) ( ٌبٌن العالقة بةٌن نسةبة الفراغةات الهوائٌةة والنسةبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة اعةادة 2الشكل رقم ) (.scrbالمواصفات المحددة من قبل ال ) (.rr( و كذلك ٌبٌن تأثٌر استخدام المضاف )rapالتدوٌر ) النموذج النسبة المئوٌة (rap)لل (its مقاومة الشد الغٌر مباشر ) (mpa) ر غٌ ال ت فل س ال ا ت ذا ت طا خل ال ج اذ نم ل عد م (c o n tr o l m ix tu re i s t h e c o n v e n ti o n a l m ix tu re w it h o u t m o d if ie r) 0 2.231 10 2.152 20 1.963 30 1.708 40 1.624 50 1.304 ت طا خل ال ج اذ نم ت فل س ال ا ت ذا ( ب ل عد لم ا r r % 1 5 ) (m o d if ie d a s p h a lt c o n c re te m ix tu re s w it h % 1 5 r r ) 0 2.492 10 2.291 20 2.162 30 1.925 40 1.726 50 1.429 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 50 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. سفلت المثلى.( منحنٌات تصمٌم مزٌج مارشال إلٌجاد نسبة اال0كل رقم )ش 8 8.5 9 9.5 10 10.5 11 4 4.5 5 5.5 ت با لث ا ( ت كن ) المئوية ل سفلت النسبة 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 4 4.5 5 5.5 ب يا س الن ا ( لم م ) المئوية ل سفلت النسبة 3.5 3.75 4 4.25 4.5 4.75 4 4.5 5 5.5 بة س لن ا ٌة ائ هو ال ت غا را لف ة ل وٌ مئ ال المئوية ل سفلت النسبة al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 51 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ( وكذلك تأثٌر استخدام المضاف rap( العالقة بٌن نسبة الفراغات الهوائٌة والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر )0كل رقم )ش (rr.) ( stabilityالثبات ) 2.1.6 االسةةفلتٌة وذلةةك الن ثبةةات الخلطةةة االسةةفلتٌة هةةو مؤشةةر مهةةم لمةةدى ( هةةو مةةن الخصةةائص المهمةةة للخلطةةاتmarshall stabilityثبةةات مارشةةال) ( ٌوضةح نتةائج الثبةات لخلطةات االسةفلت المختلفةة 5مقاومة الخلطة االسفلتٌة للعٌوب الناتجة عن االحمال المسلطة والناتجة عن حركة المرور, الجدول رقم ) ( اي بالنسةبة للخلطةات ذات االسةفلت غٌةر المعةدل نالحةظ ان زٌةادة rapلمعاد اسةتخدامها )حٌث ٌمكن مالحظة انخفاض قٌمة الثبات مع زٌادة نسبة المواد ا وعنةد االسةتمرار بزٌةادة نسةبة 21%)( أي بنسبة )حةوالً (8.19kn الى (10.31kn)انخفاض قٌمة الثبات من (20%)الى (0%)( من rapنسبة ) (rap(الةةى ال )%7.42( نالحةةظ انخفةةاض قٌمةةة الثبةةات الةةى )30 )( ًاي خةةروج قٌمةةة الثبةةات عةةن المواصةةفات المحةةددة مةةن قبةةل ال 28%اي بحةةوال ) (scrb(الخاصة بالطبقة السطحٌة والتً تحدد اقل قٌمةة ثبةات ب )8kn( امةا بالنسةبة للخلطةات االسةفلتٌة ذات االسةفلت المعةدل ب .)rr %15 نالحةظ ) وعنةةد 25%)( أي بنسةبة )حةوالً (9.49kn الةى (12.81kn)مةن بةات نالحةظ انخفةةاض قٌمةة الث (20%)الةى (0%)( مةنrapعنةد زٌةادة نسةبة ) %( اي خةةروج قٌمةةة الثبةةات عةةن المواصةةفات 45( اي بحةةوالً )7.04( نالحةةظ انخفةةاض قٌمةةة الثبةةات الةةى )40%( الةةى )rapاالسةةتمرار بزٌةةادة نسةةبة ) ( علةى قٌمةة الثبةات للخلطةة نالحةظ انةه عنةد اسةتخدام rrالمضةاف )(. أما تأثٌر استخدام kn 8( التً تحدد اقل قٌمة ثبات ب)scrbالمحددة من قبل ال ) (rr%15) (0%)كنسةبة وزنٌةة مةن االسةفلت وللخلطةات االسةفلتٌة التةً تحتةوي علةى نسةبة ( مةنrap ان قٌمةة الثبةات تةزداد مةن )(10.31kn) الةى (12.81kn) ( ًولهذا نستطٌع القول ان قٌمةة الثبةات للخلطةات ذات االسة20اي بحوال )%( فلت المعةدل بةالrr اعلةى مةن الخلطةات ذات االسةفلت غٌةر ) ( rap( والنسةبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة اعةادة التةدوٌر )marshall stability( ٌبةٌن العالقةة بةٌن ثبةات مارشةال )3المعدل, الشكل رقةم ) . (rr)وكذلك ٌبٌن تأثٌر استخدام المضاف ( flowاالنسياب ) 3.1.6 ( ٌوضةةح نتةةائج االنسةةٌاب 5(, الجةةدول رقةةم )permanent deformationج قةةٌم االنسةةٌاب تعطةةً مؤشةةر عةةن مقاومةةة التشةةوهات الدائمةةة )نتةةائ (flow( لخلطات االسفلت المختلفة حٌث ٌمكن مالحظة زٌادة االنسٌاب مع زٌادة نسبة المواد المعاد اسةتخدامها )rap اي بالنسةبة للخلطةات ذات االسةفلت ) وعنةد االسةتمرار ( (3.21mm الةى (2.06mm)تؤدي الى زٌادة قٌمة االنسٌاب من (20%)الى (0%)( من rapعدل نالحظ ان زٌادة نسبة )غٌر الم ( scrb( اي خةةروج قٌمةة االنسةةٌاب عةةن المواصةفات المحةةددة مةةن قبةةل ال )4.18( نالحةظ زٌةةادة قٌمةةة االنسةٌاب الةةى )40%( الةةى )rapبزٌةادة نسةةبة ) ( rap( نالحةظ ان زٌةادة نسةبة )rr(. امةا بالنسةبة للخلطةات ذات االسةفلت المعةدل بةال )4mmالى )2mm) )من ة السطحٌة والتً تحدد الخاصة بالطبق %( نالحةظ 40( الةى )rapوعنةد االسةتمرار بزٌةادة نسةبة )( (3.32mm الةى (2.29mm)تؤدي الى زٌادة قٌمة االنسٌاب من (20%)الى (0%)من (. ان زٌةادة قةٌم االنسةٌاب تشةٌر بصةورة عامةة ان scrb( اي خروج قٌمة االنسٌاب عن المواصفات المحددة من قبةل ال )4.42ب الى )زٌادة قٌمة االنسٌا ( تحت تأثٌر حركة المرور. permanent deformation(, ومن الممكن ان ٌتعرض لحدوث التشوهات الدائمة ال)plasticالمخلوط ٌتمتع بلدونة ) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0102030405060 ( من وزن الركامrapالنسبة المئوٌة لل) ( ٌة ائ و له ا ت غا را لف ا بة س ن a ir v o id )% modified 15%rr control mix rr0% al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 52 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ( وكذلك تأثٌر rap( والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر )marshall stability( العالقة بٌن ثبات مارشال )0رقم )كل ش (.rrاستخدام المضاف ) (.rr( وكذلك تأثٌر استخدام المضاف )rap( والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر )flow( العالقة بٌن االنسٌاب)0كل رقم )ش 0 2 4 6 8 10 12 14 0102030405060 modified 15%rr control mix rr0% ( من وزن الركامrapالنسبة المئوٌة لل) ت با لث ا s ta b il it y ( k n )) ) 0 1 2 3 4 5 6 0102030405060 ( ( ب ٌا س الن ا m m ) ( f lo w modified 15%rr control mix rr0% ( من وزن الركامrapالنسبة المئوٌة لل) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 53 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. سةبة الطبٌعٌةة فً حٌن ان انخفاض قٌم االنسٌاب من الممكن ان تعطً داللة على ان الخلطة االسفلتٌة تحتوي على نسبة عالٌةة مةن الفراغةات اي اعلةى مةن الن ( واي مةةن هةةذٌن السةةببٌن قةةد ٌةةؤدي الةةى حةةدوث تشةةققات durabilityالمحةةددة, او ٌحتةةوي علةةى كمٌةةة غٌةةر كافٌةةة مةةن االسةةفلت لمقاومةةة العوامةةل الجوٌةةة ) (cracking .وعلى المدى البعٌد خالل عمر التبلٌط )( ٌبةٌن العالقةة بةٌن 4الشكل رقةم ) االنسةٌاب(flow والنسةبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة ) (.rr( وكذلك ٌبٌن تأثٌر استخدام المضاف )rapاعادة التدوٌر ) ( indirect tensile strength test resultsئج فحص مقاومة الشد غير المباشر )نتا 2.6 ( الخةاص 6وبنةاء علةى نتةائج الفحةص المختبةري الموضةح فةً الجةدول رقةم ) ٌعتبر هذا الفحص مقٌاسا مهما لقدرة المزٌج علةى مقاومةة التشةققات, ( اي بالنسةبة للخلطةات rap( مع زٌادة نسبة المواد المعاد استخدامها )itsقٌمة ال) ( حٌث ٌمكن مالحظة انخفاضitsبنتائج مقاومة الشد غٌر المباشر) ( (1.963kn الةى (2.231kn)( مةن itsتؤدي الى انخفاض قٌمةة ) (20%)الى (0%)( من rapذات االسفلت غٌر المعدل نالحظ ان زٌادة نسبة ) ( امةا بالنسةبة 27%( اي بحةوالً )1.624( الى )its( نالحظ انخفاض قٌمة )40%لى )( اrapوعند االستمرار بزٌادة نسبة ) 12%)أي بنسبة )حوالً الةةى (2.492kn)( مةةن itsتةةؤدي الةةى انخفةةاض قٌمةةة ) (20%)الةةى (0%)( مةةن rapللخلطةةات ذات االسةةفلت المعةةدل نالحةةظ ان زٌةةادة نسةةبة ) 2.162kn) ً(10%)( أي بنسةةبة حةةوال ( وعنةةد االسةةتمرار بزٌةةادة نسةةبةrapالةةى ) (( نالحةةظ انخفةةاض قٌمةةة )%40its( الةةى )اي بحةةوالً 1.726 ) ( 5الشةكل رقةم ) ( اعلةى مةن الخلطةات ذات االسةفلت غٌةر المعةدل.rr( للخلطةات ذات االسةفلت المعةدل بةال)its(, ولهذا نستطٌع القةول ان قٌمةة )%30) ( rapبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة اعةادة التةدوٌر )( والنسةindirect tensile strength) مقاومةة الشةد غٌةر المباشةرٌبةٌن العالقةة بةٌن (.rrوكذلك ٌبٌن تأثٌر استخدام المضاف ) ( والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر indirect tensile strength( العالقة بٌن مقاومة الشد الغٌر مباشر )0شكل رقم ) (rapوكذلك ت ) أثٌر استخدام المضاف(rr.) 0 0.5 1 1.5 2 2.5 3 0102030405060 ( من وزن الركامrapالنسبة المئوٌة لل) ر) ش با م ر غٌ ال شد ال مة و قا م m p a ) i n d ir e c t t e n s il e s tr e n g th s tr e n g th control mix rr0% modified 15%rr 15% al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 54 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. االستنتاجات والتوصيات. 7 االستنتاجات 1.7 -باالعتماد على نتائج الدراسة ٌمكن استنتاج التالً: وكةذلك تقةل النسةبة (30%) الةى (0%)( مةن rap( للخلطةات ذات االسةفلت غٌةر المعةدل بزٌةادة نسةبة )25%تقل نسبة الفراغات الهوائٌةة بحةوالً ) -0 ( وبالتةالً تةؤثر rap( بزٌةادة نسةبة )scrb(, وتخرج نسةبة الفراغةات عةن حةدود المواصةفة )rr( للخلطات ذات االسفلت المعدل بال )23%والً )بح على اداء التبلٌط االسفلتً. ذلك تقةل النسةبة بحةوالً وكة (20%) الةى (0%)( مةن rap( للخلطةات ذات االسةفلت غٌةر المعةدل بزٌةادة نسةبة )21%تنخفض قٌمة الثبات بحوالً ) -0 (. rap( بزٌادة نسبة )scrb(, وتخرج قٌمة الثبات عن حدود المواصفة )rr( للخلطات ذات االسفلت المعدل بال )%25) وكةذلك (20%) الةى (0%)( مةن rapللخلطات ذات االسفلت غٌر المعدل بزٌةادة نسةبة ) ((3.21mm الى (2.06mm)من زٌادة قٌمة االنسٌاب -0 (, وتخةةرج قٌمةةة االنسةةٌاب عةةن حةةدود المواصةةفة rrللخلطةةات ذات االسةةفلت المعةةدل بةةال ) ((3.32mm الةةى (2.29mm)مةةن قٌمةةة االنسةةٌاب تةةزداد (scrb( بزٌادة نسبة )rap.) وكةذلك (20%) الةى (0%)( مةن rap( للخلطةات ذات االسةفلت غٌةر المعةدل بزٌةادة نسةبة )12%( بحةوالً )itsتنخفض قٌمة الشد غٌر المباشر ) -0 (.rap( بزٌادة نسبة )scrb(, وتخرج قٌمة الثبات عن حدود المواصفة )rr( للخلطات ذات االسفلت المعدل بال )10%تقل النسبة بحوالً ) ومةة الشةد غٌةر ( تؤدي الى تحسٌن اداء التبلٌط االسةفلتً ) الثبةات ومقاrrبصورة عامة وباالعتماد على نتائج الفحص نجد ان عملٌة استخدام المضاف ) -0 ( بالنسةبة للخلطةة االسةفلتٌة ذات االسةفلت 20%( مةن)rapالمباشر( ممةا ٌةؤدي الةى إمكانٌةة اسةتخدام نسةبة عالٌةة مةن المةواد الناتجةة مةن اعةادة التةدوٌر ال) استخدام المضاف مفٌدة. ( مما ٌدل ان عملٌةrr%15( بالنسبة للخلطات االسفلتٌة ذات االسفلت المعدل ب)30%االعتٌادي غٌر المعدل لتصل الى ) سةفلتٌة او إن أكثر المواد الناتجةة مةن مخلفةات قشةط تبلةٌط الطةرق القدٌمةة وكةذلك المخلفةات الناتجةة مةن هةدم المبةانً القدٌمةة هةً عبةارة عةن خرسةانة ا -6 نوع من المخلفات مواد جٌدة ٌمكةن إعةادة اسةتخدامها فةً اسمنتٌة تحتوي فً الجزء األكبر منها على ركام بحالة جٌدة وهذه الدراسة تبٌن امكانٌة اعتبار هذا ال مشارٌع مختلفة والتً تتطلب كمٌات كبٌرة من الركام كمشارٌع انشاء الطرق او صٌانتها. الً تسةاعد فةً تقلٌةل ان عملٌة إعادة تدوٌر المخلفات الخرسانٌة لها إٌجابٌات واضحة على البٌئٌة تتمثل فً تقلٌل الحاجة لمواقةع ردم هةذه المخلفةات وبالتة -5 .التلوث البٌئً الركةام تمثةل وهناك منافع اقتصادٌة من ناحٌة أن الخلطات اإلسفلتٌة تكون أقةل تكلفةة عنةد اسةتخدام ركةام نةاتج مةن عملٌةة اعةادة التةدوٌر بسةبب أن نسةبة -0 ع جدٌةدة لمقةالع األحجةار ممةا ٌةؤدي إلةى زٌةادة المحافظةة علةى هةذه ( تقرٌباً من الخلٌط األسفلتً, وهذا ٌؤدي الى تقلٌل الحاجة إلى اٌجةاد مواقة95%حوالً ) الموارد الطبٌعٌة فً البلد او التقلٌل استنزافها. التوصيات 2.7 ( للخلطةات ذات االسةفلت غٌةر المعةدل و 10%( فةً الخلطةات اإلسةفلتٌة بنسةبة )rapاستخدام نسب أقل من الركام الناتج مةن عملٌةة اعةادة التةدوٌر ال ) -0 ( ثةم زٌةادة هةذه النسةب مسةتقبالً بعةد أن ٌةتم قبولهةا واجةراء فحوصةات اخةرى كفحةص عجلةة rr( بالنسبة للخلطات ذات االسفلت المعدل بال )20%نسبة )ب ( واالطمئنان إلٌها من قبل الجهات المعنٌة وخصوصا الهٌئة العراقٌة للطرق والجسور.wheel track testالمسار ) ه الدراسة تشجع وتحث على اجراء دراسات وبحوث مشابهة لتقٌٌم عملٌة اعادة تدوٌر مخلفات البنةاء وخاصةة المةواد الخرسةانٌة واعةادة النتائج االولٌة لهذ -0 استعمالها مرة اخرى. تجةة مةن اعةادة التةدوٌر ( وغٌره من المضافات مما قد ٌؤدي الى زٌادة نسةبة المةواد الناsbsاستعمال مواد مضافة اخرى كالستاٌرٌن بٌوتادٌن ستاٌرن ) -0 ( فً تجهٌز الخلطات االسفلتٌة التً تستعمل فً انشاء الطرق.rapال ) references 1al-bana’a, j.r., isma’ail, (2009). “effect of polymer type on the performance of modified asphalt paving mixture” m.sc, civil engineering, university of babylon. 2al-dubabe i.a., (1996) “polymer modification of arab asphalt”, ph.d thesis, king fahd university of petroleum & minerals (kfupm), dhahran, saudi arabia. 3ashto (2005). aashto designation: t322, determining the creep compliance and strength of hot-mix asphalt (hma) using the indirect tensile device, the american association of state highway and transportation officials, washington, d. c., usa. 4astm d-6927, (2006). “resistance to plastic flow of bituminous mixtures using marshall apparatus”, american society of testing and materials. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 55 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5besseche, t., m. kroge, and k. mcglumphy, (2009) “full-depth reclamation with engineered in fairburn, georgia”, proceedings of the 88th annual meeting of the transportation research board, washington, d.c., usa. 6copeland, a. and bukowski, j., (2001) " asphalt pavement recycling with reclaimed asphalt pavement (rap)" federal highway administration, usa. 7-holtz, k. and eighmy, t.t., (2000) "scanning european advances in the use of recycled materials in highway construction", public roads, uk. 8ikeda, t., and kimura, m., (1997) "recent development in recycling asphalt pavements in japan", proceedings of 8th international conference on asphalt pavements, seattle, washington, usa. 9jeffrey, m., (1992) “recycling asphalt pavements: past, present and future” recycled materials resource center, university of new hampshire. 10scrb/r9, (2004). general specification for roads and bridges, section r/9, hot-mix asphalt concrete pavement, revised edition. state corporation of roads and bridges, ministry of housing and construction, republic of iraq. ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨١ التسليح بألياف هجينة وتأثيرها على التوصيل الحراري لمادة متراكبة بولميرية ي إبراهيم الموسويعل. م.م بابل–المعهد التقني الخالصة تهدف هذه الدراسة إلى البحث في تأثير التسليح بألياف هجينة مكونة من ألياف النخيل الطبيعية وألياف تم تسليح الراتنج بألياف النخيل الطبيعية . (ay103)الكاربون على السلوك الحراري لراتنج اإلرلدايت ، (1.75g\cm3) ذات كثافة سطحية) ٠°(ية اإلتجاه أحادخرى مقواة بألياف الكاربونومقارنتها مع مادة ُأ بعدها تم دمج هذين النوعين من األلياف في أرضية واحدة لتكوين مادة متراكبة هجينة والتي تم حساب ادة للم(k) لحساب معامل التوصيل الحراريرإستخدمت معادلة فوري. معامل التوصيل الحراري لها أيضاً لقد أظهرت النتائج التي تم الحصول عليها من إختبار الموصلية الحرارية إن قيمة التوصيل . المتراكبة الناتجة . هو أعلى منه في حالة التسليح بألياف الكاربون واأللياف الهجينة الطبيعيةالحراري أللياف النخيل .هجينة ألياف لية الحرارية،وِصالممادة متراكبة،: الكلمات الدالة reinforcing by hybrid fibers and its effect on thermal conducting for polymeric composite material ali i. al-mosawi technical institute-babylon abstract . the aims of this study is to investigation the effect of reinforcing with hybrid fibers included natural palms fibers and carbon fibers on thermal behavior of araldite resin(ay103) . this resin was reinforced with natural palms fibers is studied and compared it with another material reinforced by carbon fibers )°٠( with (1.75g/cm3) density ,and then these two types of fibers combined together in same matrix to make a hybrid composite material and also calculated the range of it's thermal conductivity coefficient .fourier equation used to calculate the thermal conductivity coefficient(k) to obtained composite material and. the results obtained from thermal conductivity test show that the thermal conducting value of natural palms fibers higher than reinforcing with carbon and hybrid fibers . keywords: composite material, thermal conductivity, hybrid fibers . ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٢ ).introduction( المقدمة عند وجود فرق حراري بين سطحين سوف تنتقل الحرارة من السطح ذو درجة الحرارة األعلى إلى الـسطح وعلى هذا األساس يمكـن تعريـف . ذو درجة الحرارة الواطئة ، وتُعرف هذه الظاهرة بالموِصلية الحرارية رة عبر وحدة المساحة خالل وحدة الزمن عند وجود إنحدار الموِصلية الحرارية على إنها معدل إنسياب الحرا تختلف آلية التوصيل الحراري من مادة إلـى أخـرى ] . 1[ حراري بين سطحين مقداره درجة مئوية واحدة تعتمـد . والذي من خالله تُصنف المادة على إنها موصلة أو عازلـة ) صلبة،سائلة،غازية(وحسب حالة المادة . توجيه الجزيئات ،الحجم البلوري ، ودرجة النقاوة : في الراتنجات على عدة عوامل هي الموِصلية الحرارية وهو أحـد أسـاليب إنتقـال (في المواد غير المعدنية ومن ضمنها الراتنجات يكون إنتقال اإللكترونات ضعيفاً ازات الهيكليـة أو ال يكون هناك إنتقال إلكتروني لذلك فإن التوصـيل الحـراري يتحـدد بـاإلهتز ) الحرارة )structure vibration ( وهذا السبب هو الذي يجعل من المواد الراتنجية أقـل توصـيالً للحـرارة مـن ]. 2[المعادن .)composite materials(المواد المتراكبة مـن هـذا ية والغـرض ئمختلفتي الخواص الميكانيكية والفيزياأو أكثر تتكون المادة المركبة من جمع مادتين على األمثلة يوجد في الطبيعة الكثير من .األصليةستنباط خواص جديدة لم تكن متوفرة في المواد إالجمع هو ـ أما. السليلوز مع مادة الخشب أليافالمواد المركبة ومنها باألليـاف ن تـسليح الراتنجـات إ في الصناعة ف ]:4 [ر مادتين هما لتصنيع مادة مركبة يجب توفو. ]3[ نتشاراًإ األكثرالصناعية هي وتكون أما مواد معدنية أو سيراميكية أو مواد راتنجية وهي األكثر ) : matrix material( مواد األساس-١ ومن األمثلة على المواد الراتنجية . إستعماالً وإنتشاراً ِلما تتميز به من خواص ميكانيكية وعزل حراري جيد .لبولي أسترهو راتنج الفينول ، اإليبوكسي ، وراتنج ا التسليح ،دة طرق للتسليح منها التسليح بالدقائقهناك ِع): reinforcement material( مادة التسليح -٢ باأللياف وكمثال على أنواع األلياف المستخدمة هي ألياف الكاربون وألياف كيفالر و ، والتسليحبالتشتت ما شيوعاً نظراً ِلأكثر مواد التسليح ) reinforcing by fibers (باأللياف التسليح يعتبر . ألياف الزجاج بأنواع وأشكال مختلفة فمنها ما يكون بشكل األليافتتميز به من قوة كبيرة مقارنة بالمواد الراتنجية،وتكون بشكل ظفائر محاكةأو طع مقَأومستمر ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٣ .) 103ay( ))103ay (resinaraldite(إلرلدايت راتنج ا ة ب مجموعـة الراتنجـات المتـصل والذي يقع ضمن اإليبوكسي إلى راتنج (ay103)إلرلدايت ي راتنج ا ينتم التي تتألف (epoxide) يحتوي راتنج اإليبوكسي على مجموعتين أو أكثر من مجاميع اإليبوكسايد. بالحرارة الجزيئـات اُألخـرى من ذرة ُأوكسجين مرتبطة مع ذرتي كاربون ترتبط مجموعة اإليبوكسي كيميائيـاً مـع ـ ت].5 [(curing)لتشكيل شبكة ثالثية األبعاد ذات ربط تشابكي بعملية المعالجة اإليبوكـسي اتتميـز راتنج بالصالدة والمقاومة الكيميائية العاليتين نسبياً إضافة إلى ذلك يمتلك هذا الراتنج قابلية إلتصاق نـوعي عـالي لمتمثل في مجموعة اإليثرات والهيدروكسيل والمجاميع القطبية التـي بسبب التركيب الكيميائي لهذا الراتنج وا .تعطي متانة وإلتصاق عالية وتكسب المادة صالدة وقوة تتفاعل هـذه الراتنجـات مـع . اإليبوكسي في التطبيقات التي تتطلب إداءاً وظيفياً عالياً اتستعمل راتنج ت بإنبعاث الماء أو تحرر أي منتجات ثانوية مما يجعـل المصلدات أثناء المعالجة ويكون التفاعل غير مصحوب وبالتالي يكتسب الراتنج قوة وخواص ميكانيكية عالية إضـافة إلـى %) ٢أقل من (التقلص الحجمي قليل جداً الربط التشابكي ووجود الـسالسل ذلك تمتلك راتنجات اإليبوكسي المعالجة متانة عالية نتيجة للبعد بين نقاط .(ay103)إلرلدايت راتنج ا يوضح التركيب الكيميائي ل)١(الشكل رقم ].4[ لمتكاملةاإلليفانية ا .)carbon fibers (ألياف الكاربون الخمولية حيث تمتلك مقاومة عالية ضد الرطوبة وألغلب :تمتلك ألياف الكاربون العديد من المزايا منها رارية عالية على طول محور األلياف ، وثبات األبعاد المواد الكيميائية الشائعة ، موصلية كهربائية وح تعاني جميع أنواع ألياف الكاربون من . نصهار عاليةإمتالكها لدرجة إوإنخفاض التمدد الحراري المحوري ،و تتضمن ألياف . الكسر الهش تحت تأثير اإلجهاد وهذا متوقع نظراً إلرتفاع مقاومتها وإنخفاض مطيليتها . والتي هي أحد األشكال المتآصلة للكاربون(turbostratic graphite)صغيرة من مادة الكاربون بلورات ألياف بشكل أو (woven roving) بشكل ظفائر محاكة نحيث تكوألياف الكاربون عدة من هنالك أنواع . ]6[شرطة أ على شكل خيوط وأو (chopped strand)مقطعة ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٤ .)palms fibers (ألياف النخيل والـسيليلوز ) cellulose fibers(إلى مجموعة األليـاف الـسليلوزية ) palms fibers(مي ألياف النخيلتنت . متكون من جزيئات الكلكوز المرتبطة مع بعضها بسالسل خطية ) polysaccaride(عبارة عن سكر متعدد يمكـن أن تـستخدم . ل فيه تتوفر ألياف النخيل بكثرة في العراق نظراً لكونه البلد األول من حيث عدد النخي األلياف السليلوزية ومن ضمنها ألياف النخيل بشكلها الخام فـي الـصناعة لكلفتهـا المنخفـضة وخواصـها .الميكانيكية والحرارية الجيدة ، أو يمكن أن يتم تحويلها إلى أنواع جديدة من األلياف ومنها الحرير الصناعي .المواد المستخدمة في البحث :لبحث إستخدام المواد التالية تم في هذا ا هـذا الـراتنج % .٢ إليه بنسبة (hy956)يصلد هذا الراتج بإضافة مادة : (ay103) اإلرلدايت راتنج-١ .(ciba-geigy)مجهز من شركة ذات كثافة سطحية ) ٠°( اإلتجاه تم إستخدام ألياف الكاربون ُأحادية : (carbon fibers) ألياف الكاربون -2 (1.75g/cm3). من شركة ةمجهزهذه األلياف (hyfil ltd .,uk). الجـزء (تم إستخدام األلياف التي تحيط بقلب النخلة .(natural palms fibers) ألياف النخيل الطبيعية -3 ) . الداخلي .تحضير نماذج إختبار الموصلية الحرارية اإلرلدايت راتنج يتم خلط كمية من : ي وهي تحضر كاآلت (3mm) وسمك (25mm)تكون هذه النماذج بقطر (ay103) الراتنج على سطح القالب الداخلي وتنشر بفرشة لـضمان هذا توضع كمية من بالمادة المصلدة ثم ج عليها وهكـذا لبقيـة تن من الرا أخرى ثم نضع كمية األلياف من األولىتوزيعه بانتظام بعدها توضع الطبقة تم إستخدام الطريقة الوزنية في حساب كمية كل من األلياف .لسمك المطلوب الطبقات لتتكون مادة متراكبة با أليـاف % ٥٠+ ألياف كاربون % ٥٠راتنج أما نسبة األلياف فهي % ٤٠ألياف و % ٦٠والراتنج والتي هي ـ يرك لتتصلب ، بعدها تهذه النماذج وت كبسنخيل في المادة المتراكبة الهجينة ،بعدها ت ب تم إخراجها من القال .مال التصلبإلك) 75ºc( في فرن درجة حرارته هاووضع ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٥       ∆ ∆ ××−= x t akq ( )xt∆∆ . قياس الموصلية الحرارية وينص هذا ) (k في حساب معامل الموصلية الحرارية (fourier law) ستخدام قانون فورير إيمكن : القانون على : حيث q = كمية الحرارة المارة بوحدة الزمن وتقاس بوحدات( w ) k = الموصلية الحرارية ويقاس بوحدات معامل ( w/m.ºc ) a = نسياب الحرارة وتقاس بوحداتإمساحة مقطع (m2) ( ºc/m )التدرج الحراري نسبة للمسافة ويقاس بوحدات = والمصنع من قبل (heat conduction unit) لية الحراريةوِص يوضح جهاز قياس الم( 2 )الشكل رقم . (p.a.hilton ltd england)كة شر . ) discussion& results (النتائج والمناقشة وعالقتها بدرجة الحرارة ، حيث تزداد (ay103)راتنج اإلرلدايتل يمثل الموصلية الحرارية)3(الشكل رقم دة اإلهتزازات في هذه الموصلية بزيادة درجة الحرارة وهذا اإلرتفاع في الموصلية الحرارية يعود إلى زيا تستخدم التسليح باأللياف للحصول . الهيكل الداخلي للراتنج نتيجة إلرتفاع درجة الحرارة التي يتعرض لها على خواص حرارية وميكانيكية جديدة غير متوفرة في الراتنجات حيث تتم التسليح بأنواع مختلفة من .]7[األلياف الصناعية ليح بألياف النخيل على الموصلية الحرارية لراتنج اإلرلدايت ، حيث تبدأ يبين تأثير التس)4(الشكل رقم الموصلية الحرارية للمادة المتراكبة باإلرتفاع بزيادة درجة الحرارة ويعزى السبب في ذلك إلى إن ألياف ة إلى النخيل تعمل على إمتصاص الطاقة الحرارية وبالتالي ترتفع درجة حرارتها ومن ثم إنتقال هذه الحرار ، ويكون اإلنتقال الحراري عالي نسبياً بسبب قدرة هذه )منطقة تدرج حراري(الجهة اُألخرى من العينة .األلياف على نقل الحرارة ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٦ يبين الموصلية الحرارية لراتنج اإلرلدايت المسلح بألياف الكاربون ،إذ تؤدي هذه األلياف إلى )5(الشكل رقم وهذه الزيادة في الموصلية متوقعة نظراً لقدرة األلياف على التوصيل رفع الموصلية الحرارية للراتنج تكون الزيادة في الموصلية الحرارية في حالة التسليح بألياف الكاربون أقل . الحراري مقارنة بالمادة الراتنجية كاربونية مما هي حالة التسليح بألياف النخيل حيث إمتصاص الحرارة ومن ثم نقلها تكون أقل في األلياف ال . لمدى أعلى من ألياف النخيلةألنها تقاوم الحرار يوضح التأثير المزدوج للتسليح بألياف النخيل وألياف الكاربون على الموصلية الحرارية )٦(الشكل رقم ، وكما هو واضح من الشكل فإن الموصلية الحرارية تبدأ باإلرتفاع )مادة متراكبة هجينة( لراتنج اإلرلدايت ادة درجة الحرارة ولكن بنسبة أقل مما في ألياف النخيل وأعلى بقليل نسبياً في حالة ألياف الكاربون ، مع زي إذ تقوم ألياف الكاربون بالحد من الموصلية الحرارية أللياف النخيل بسبب الفرق في معامل الموصلية .]8[الحراري بينهما وبالتالي خفض الموصلية الحرارية للمادة المتراكبة ككل ).conclusions(اإلستنتاجات ألياف النخيل ، ألياف ( إرتفاع الموصلية الحرارية للراتنج بعد التسليح باأللياف ولحاالت التسليح الثالث-١ ).الكاربون ، األلياف الهجينة ف الكاربون التوصيل الحراري للمادة المتراكبة المقواة بألياف النخيل هو أعلى منه في حالة التسليح بأليا-٢ .واأللياف الهجينة . إمكانية إستخدام التسليح باأللياف الهجينة من الناحية اإلقتصادية وكذلك موصليتها الحرارية المعتدلة -٣ ).references(المصادر 1incropera ,f.p. and dewitt ,d.p. , 1996 “introduction to heat transfer”,3rd edition, john wiley &sons. 2halem, ali hoby,1999 “ improvement properties of reinforced plastic materials ”, msc thesis , engineering college , babylon university , iraq. 3moslem,ali ibrahim ,2003 “ study using of antimony trioxide material as a flame retardant material ”, msc thesis , babylon university , iraq . 4mallick ,p.k. ,2007 “fiber-reinforced composites: materials, manufacturing, and design” third edition , crc press, nov. 5michel biron, 2007 “ thermoplastics and thermoplastic composites ” , first edition , elsevier. ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٧ ]4 [(ay103)اإلرلدايت التركيب الكيميائي لراتنج) : ١(الشكل رقم جهاز قياس الموصلية الحرارية) : ٢(الشكل رقم 6e.p.degarmo, j.t. black, and r.a. kohser, 2008 “ materials and processes in manufacturing ” , 10th edition , john wiley & sons. 7bogomolov v. and kartenko n. , 2003 “thermal conductivity of the opalepoxy resin nanocomposite ” , physics of the solid state , vol 45,no 5,pp.957-960. 8craig w. ohlhorst wallace l. vaughn, philip o. ransone, and hwa-tsu tsou, 1997 “thermal conductivity database of various structure ca rbon-carbon composite materials ”,nasa technical memorandum 4787 , november. ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٨ ألياف النخيل+ راتنج :)٤(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc ج اإلرلدايت راتنالتوصيل الحراري ل :)٣(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc ألياف الكاربون+ راتنج :)٥(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc ألياف هجينة+ راتنج :)٦(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc 30 35 40 45 50 55 60 65 70 75 80 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 30 35 40 45 50 55 60 65 70 75 80 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 2.10 2.20 2.30 2.40 2.50 2.60 2.70 2.80 30 35 40 45 50 55 60 65 70 75 80 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 30 35 40 45 50 55 60 65 70 75 80 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 13-2-2011.pdf 143 the specific goals of this study are to determine the optimum inflow to the filters (hydraulic loading rates) and media characteristic such as the effective size, the particle size distributions within the bed media. in addition to modify the traditional slow sand filter to gain better flow control to treat grey water of high turbidity. three set of experiments were carried out during nine months from april to december in mustansiryiah university, college of engineering, environmental hydraulic laboratory. the first set of experiments were achieved by using (1m height) sand of effective diameter 0.35 mm, uniformity coefficient, uc=2.2 and porosity (39%), the second set of experiments were carried out by using sand of 0.75mm diameter, uc= 2.9 and porosity (43%) to study the effect of grain size of sand on water head over sand surface and removal efficiency. while the other set of experiments were done by using (0.7m height) sand of effective diameter 0.35 mm, uc=2.2 and porosity (39%) to study the effect of filter height of sand on removal efficiency. measurements of chemical, physical and bacterial parameters were achieved during nine months from april to december. these parameters include turbidity, ph, po4-2, bod5, cod, tds, tss, and coliform removal for treated grey water. results show that filter loading rate has been determined to be not more than 680 l/hr/m2 which removal efficiency of bod5 was (51%) and minimum filter loading rate has been tested to be 212 l/hr/m2 which removal efficiency of bod5 was (83%). : ) ( . 144 ) .( )٠.٣٥() ١ ()uc=2.2 ( )٠.٧٥(%). ٣٩ ( )uc=2.9 ()١(%)٤٣( )٠.٣٥() ٠.٧ ()uc=2.2 ()٣٩.(% : . bod) ٢/ساعة/٦٨٠( %).٨٣(bod) ٢/ساعة/٢١٢(%) ٥١( the process slow sand filtration (ssf) percolates untreated water slowly through a bed of porous sand, with the influent water introduced over the surface of the filter, and then drained from the bottom. biosand filter was designed and constructed for removing suspended organic, inorganic matter and pathogenic organisms. the treatment technology must be economical to build, and simple to operate and maintain given the adverse economic and environmental conditions. for these reasons, slow sand filtration has been selected as a potential water treatment technology. the resulting recommendations are planned around and sized appropriately for use by the many small community for water treatment in baghdad. the major benefits of slow sand filtration are due to the microbiology of the filter. the microbiological community must be kept alive for the filter to be effective. in a conventional slow sand filter, oxygen is supplied to the organisms through dissolved oxygen in the water. consequently, they are designed to be operated continuously. in addition, because the water moves through at a slow rate, the filter beds tend to be very large. a bucket of water is poured into the top of the filter as necessary. the water simply flows through the sand media and is collected in another bucket or gravel container at the base of the spout. it normally takes a few minutes for the entire bucket to make its way through the filter. there are no valves or moving parts and the design of the outlet system ensures that a minimum water depth of five centimeters is maintained over the sand when the filter is not in use. when the water is flowing through the filter, oxygen is supplied to the biologic layer at the top of the sand by the dissolved oxygen in the water. when water sand levels is too shallow (less than 50mm) biolayer dries out especially in hot days during periods from may to september causing major problem for restarting after back washing and pause period. an other problems may be occurred when water sand level is too deep (more than 500mm during continuous run and 100mm during pause period) because of insufficient oxygen for biolayer. originating in europe, slow sand filtration is classified as the first, modern water treatment technology (ellis, 1985). this filtration process removes particles and microorganisms by the slow percolation of water through a porous sand media. unlike other water treatment technology (i.e. rapid sand filtration), conventional slow sand technology does not involve chemical or physical pretreatment applications (collins etal, 1992). problems associated with highly turbid waters made conventional slow sand treatment impractical for communities plagued with such source water. conventional slow sand filters clogged under such conditions, and the technology of choice became rapid sand filtration, due to its ability to produce large quantities of acceptable finished water from highly turbid source water 145 (ellis, 1985). an additional factor influencing the move to rapid sand filtration was public support for the newest technology available, regardless of community size (logsdon, 1991). recently, however, slow sand filtration technology has received a resurgence of interest in the united states (logsdon, 1991). increased concerns regarding the persistence of cysts in many municipal water systems has led to a greater interest in slow sand technology (lange, bellamy, hendricks and logsdon, 1986; fogel, isaac-renton, guasparini, moorehead and ongerth, 1993). with the 1989 passage of the surface water treatment rule (swtr) in the united states, many previously unfiltered surface water sources now require filtration (logsdon, 1991; brink and parks 1996). the united states environmental protection agency (epa) has set a turbidity standard < 1 nephelometric turbidity unit (ntu) 95 percent of the time, never to exceed 5 ntu’s. furthermore, the removal or inactivation of cysts is to be > 3-logarithmic (log) and virus removals are to be > 4-log removal. removals of microorganisms in slow sand filters have proven to be 2 – log to 4 – log in effluent of slow sand filters (hendricks and bellamy, 1991). the effectiveness of slow sand filtration in removing cysts is well documented (fogel et al., 1993; bellamy, hendricks and logsdon, 1985; ellis, 1985). research in the united states and great britain has shown the effectiveness of slow sand filtration in removing viruses and bacteria (wheeler and lloyd, 1988; poynter and slade 1977 as cited by hendricks and bellamy, 1991). the effectiveness, affordability and ease of operation available with slow sand filtration systems is appealing to small communities (those under 10,000 people) that lack significant capital for constructing, operating and maintaining rapid sand filtration facilities (riesenberg, walters, steele, and ryder, 1995; li, ma and du, 1996). as of 1984, a survey by simms and slezak identified 71 slow sand filtration facilities in operation in the united states. brink and parks (1996) stated that a preliminary report compiled for the american slow sand association indicated that 225 such facilities were in use in the united states. it is anticipated that additional facilities will be built by small communities needing affordable, effective water treatment technology to comply with the surface water requirements established in 1989 (logsdon, 1991; brink and parks, 1996). based on slow sand filter research, the biosand filter may also remove some heavy metals (muhammad, 1997; collins, 1998). there is also a design modification known as the kanchantm arsenic filter that is effective in removing both pathogens and 85-90% of arsenic from source waters (ngai, 2007). preliminary health impact studies estimate a 30-40% reduction in diarrhea among all age groups, including children under the age of five, an especially vulnerable population (liang, 2007; sobsey, 2007). grey water is pumped to the slow sand biofilter made from pvr of 1800mm height and 300mm diameter (1) to remove suspended organic matter, algae etc. overflow outlet (4) back to holding tank (2) maintains constant depth to water layer as shown in . the slow sand biofilter consists of: a water storage layer (5), a bed of fine sand or media filter bed (6) ( ), diffuser plate (7) and gravel layers (9) ( )to support filter bed. the outflow (10) may be fitted with a flow regulator valve to control the filtration rate, flow meter (8) is used for measured treated water flow, and a piezometers (open tube) (11) to measure filter head loss. a small collection tank (12) collects filtered water for distribution by pump (13). the thermometer (3) is put in the middle of water storage zone to measure water temperature. the first set of experiments were achieved by using sand of effective diameter 0.35 mm, uc=2.2 and porosity (39%) ( ), while the other set of experiments were carried out by using sand of 0.75mm uc= 2.9 and porosity (43%) ( ) to study the effect of grain size of sand on water head over sand surface and removal efficiency. the effective size es or d10 is defined as the sieve size in mm that permits passage of 10% by weight of the sand. the uniformity coefficient (uc) of a sand is defined as d60/d10, uniform (the uc is 2.6), and be washed free of loam, clay, and organic matter. fine particles will quickly 146 clog the filters and frequent cleaning will be required. a sand that is not uniform will also settle in volume, reducing the porosity and slowing the passage of water. measurements of chemical, physical and bacterial parameters were achieved during six months from april to december. these parameters include turbidity, ph, po4-2, bod5, cod, tds, tss, and coliform removal for treated grey water. the efficiency of ssf depends on the particle size distribution of the sand, the ratio of surface area of the filter to depth and the flow rate of water through the filter. the biosand filter has been designed to allow for a filter loading rate (flow rate per square meter of filter area) which has proven to be effective in laboratory and field tests. this filter loading rate has been determined to be not more than 680 liters/hour/square meter (q=48l/h) which removal efficiency of bod5 was (51%) and the minimum filter loading rate has been tested to be 212 liters/hour/square meter (q=15l/h) which removal efficiency of bod5 was ( 83%) ( ). the percentage removal of contaminants is inversely proportional to the flow rate through the filter because the biologic reduction of contaminants takes time. the amount of water that flows through the biosand filter is controlled by the size of sand media contained within the filter. if the rate is too fast, the efficiency of bacterial removal may be reduced. if the flow rate is too slow, there will be an insufficient amount of treated water, the users will become impatient and may use contaminated sources of water. the micro-organisms are more closely confined near the surface of the sand bed in a continuously operated slow sand filter because the oxygen supply is limited by diffusion from the surface. because of the thin biologic zone, there is a shorter contact time between the bio film and water during filter runs. slower filtration rates are therefore required in a biosand filter to produce water of similar bacteriological quality as a continuously operated filter. changes in the water depth will change the depth of the bio zone and removal efficiency of biofilteration. a greater water depth (500 mm) results in lower oxygen diffusion and consequently a thinner bio zone and reduce the removal efficiency. with increasing water depth (more than 500 mm), the bio-layer moves upwards in the sand bed and thus oxidation and metabolism decrease. eventually, the filter becomes a non living system. changes in the water depth above the sand surface will cause a change in the biological zone disrupting the removal efficiency of the filter. results of analysis measured such as turbidity and bod5 show that the removal efficiency of turbidity and bod5 in the first biosand filter (sand of effective diameter 0.35 mm and porosity (39%) and 500mm water depth was 89% and 43% respectively, while the removal efficiency of turbidity and bod5 in the second biosand filter (sand of effective diameter 0.75 mm and porosity (43%) and 500mm supernatant water depth) was 81% and 64% respectively. the removal efficiencies of different depth on bod5 and turbidity values is shown in . a water depth of greater than 500 mm results in lower oxygen diffusion and consequently a thinner biological zone. a high water level can be caused by a blocked outlet spout or by an insufficient amount of sand media. as the water depth increases, the oxidation and metabolism of the microorganisms within the biological zone decrease. eventually the layer dies off and the filter becomes ineffective. the water passes through the sand from top to bottom. any larger suspended particles are left behind in the top layers of sand. smaller particles of organic sediment left in the sand filter are eaten by microscopic organisms including bacteria and protozoans which ’stick’ in the layers of slime that form around the sand particles and the clean water which passes through the filter is safe 147 to drink. provided that the grain size is around 0.1mm in diameter, a sand filter can remove all fecal coliforms (bacteria that originate from feces) and virtually all viruses. biosand filters have been shown to remove most pathogens found in raw water. if the grey water is highly contaminated, the outlet water may still have some contaminants. the same source of water should be used consistently because the biolayer cannot quickly adapt to different water quality. over time, the micro-organisms in the biologic layer become adapted to conditions where a certain amount of food is available. the turbidity of the source water is also a key factor in the operation of the filter. if the turbidity is greater than 50 ntu, the raw water should be settled or strained before it goes though the biosand filter. in a slow sand filter, the filter bed is constructed of a medium with high surface area which can be colonized by suppressive micro-organisms. this fine media also presents a physical barrier to the passage of spores of plant pathogens. in a ssf, plant pathogens recirculation in the irrigation water are captured in the filter media, and at slow rates of water filtration (100-200 l/hr/m2 surface area of the first filter), are acted upon by the antagonistic micro organisms that colonized the filter bed. the maximum water level may be automated by using a float and a control valve or by periodically adjusting the valve manually to maintain the water lever near the overflow line. the depth of the filter bed has a strong influence on the effectiveness of the filtration and should be at least 0.75 1.0 meters. high turbidity levels in the raw water will prematurely block the slow sand biofilter, leading to a much shortened time span between cleanings and an overall deterioration of the water quality. high turbidity in the raw water may shorten the filter life from several months to a matter of days. other means of turbidity reduction include holding ponds and sedimentation tanks. the processes that occur in the schmutzdecke are enormously complex and varied, but the principal one is the mechanical straining of most of the suspended matter in a thin dense layer in which the pores may be very much less than a micron. the thickness of this layer increases with time from the initial installation to the point where the flow rates become unacceptably small, when it is usually about 25 mm. the greatest benefit of the ssf lies in its ability to trap bacteria and viruses in this schmutzdecke. bacterial and biological activity maximizes in there but will continue at a decreasing level down into the sand of the filter bed. a certain minimum level of dissolved oxygen should be present to support the aerobic actions that occur in the bed. after the initial installation of the ssf, the formation of the schmutzdecke and bacterial/biological activity in the bed may take days or weeks depending strongly on the ambient temperature. the comparsion between biosand filters (1 &2) and previous works is shown in . slow sand filters consistently demonstrate their effectiveness in removing suspended particles with effluent turbidities below 1.0 nephelometric turbidity units (ntu), achieving 90 to 99 + percent reductions in bacteria and viruses, and providing virtually complete cyst and oocyst removal. the parameters limitations are shown in . chlorination processes are most widely used for water disinfestations. the effectiveness of such chemical treatments in controlling plant pathogen depends on correct dosages and treatment times, control of suspended particulate matter in the recycled water, and foolproof monitoring systems. chemical treatments have proven effective when used properly, however they are relatively expensive and present safety issues to the handlers and the environment. sand filters cannot cope with heavy metals or other excessive pollutants. their prime purpose is to remove bacteria and particles. it is not appropriate to use the technology to clean up water contaminated by chemicals. if water source does have a high level of contamination, ideally you should locate a new one. if this isn’t possible other methods of filtration may be used, depending on the level of contamination. if the water contains sediment, it should be passed through an initial settling tank before it gets to the sand filter. 148 it normally takes a period of three weeks for the biologic layer to develop to maturity in a new filter. during that time, both the removal efficiency and the oxygen demand of the filter increase as the biologic layer grows and increase the pressure head drop . the filters are cleaned by stirring up the thin layer of sand at the surface and scooping out the resulting dirty water. after cleaning, the removal efficiency declines somewhat, but increases very quickly to its previous level as the bio-layer is re-established. over time, the pore opening between the sand grains will become clogged with sediment. as a result, the water flow rate through the filter will slow down. to clean the filter, the surface of the sand must be agitated to re-suspend the sediment in the standing water. the dirty water can be removed using a small container. the process can be repeated as many times as necessary to regain the desired flow rate. after cleaning, it will take the biolayer up to a week to re-establish itself and return the removal efficiency to its previous level. the diffuser plastic plate of 10 mm mesh diameter was designed and laid on the free sand surface to damp the strong shock of turbid grey water on sand bed and to prevent the disturbance of the sand layer when water is poured into the filter. different experiments were conducted to study the water temperature affects. water temperatures ranged from 16 oc to 32 oc were experimented for biosand filter of (0.35 mm dia.) and 1 m depth as shown in . the removal efficiency for biological treatment also depends upon empty bed contact time (ebct), results show that efficiency of cod and bod5 increases when ebct increases ( ). three sets of experiments were achieved to evaluate the optimum hydraulic loading rate for two different grain sizes of sand media and two different depths of sands filter, all these experiments were achieved on grey water. 1. the removal efficiency of bod5 increases from 51% at hydraulic loading 680 l/hr/m2 to 83% when filter loading rate be tested at 212 l/hr/m2. 2. the removal efficiency of turbidity for the first biosand filter (sand effective diameter d10=0.35 mm, porosity = 39%) was 89%, while the removal efficiency of the second biosand filter (d10 = 0.75mm and porosity = 43%) was 81%. 3. the removal efficiency of cod increases when empty bed contact time (ebct) increase. the cod removal efficiency mesursed from 41% at ebct = 48 min to 76% at ebct = 9 min. 4. the increasing in water temperature increases the removal efficiency of bod5 and cod. the bod5 removal efficiency measured from 64% at t = 18 oc to 78% t = 32oc. 1. bellamy, w.d., hendricks, d.w., logsdon, g.s. (1985). slow sand filtration:influences of selected process variables. journal of the american water works association,77 (12), 6266. 2. brink, d.r. and parks, s. (1996). update on slow sand/advanced biological filtration research. in n. graham and r. collins (eds.), advances in slow sand and biological filtration (pp. 11-18). england: john wiley & sons ltd. 3. collins, m.r., eighmy, t.t., fenstermacher j. m., spanos, s. (1992). removing naturalorganic matter by conventional slow sand filtration. journal of the america water works association, may 1992, 80-90. 4. ellis, k.v. (1985). slow sand filtration. crc critical reviews in environmental control, 14 (4) pp315-354. 149 5. fogel, d., isaac-renton, j., guarsparini, r., moorehead, w., ongerth, j., (1993)removing giardia and cryptosporidium by slow sand filtration. journalof the american water works association, november 1993, 77-84. 6. haarhoff, j., and cleasby, j. l., (1991). “ biological and physical mechanisms in slow sand filtration”, in g.s. logsdon (ed), slow sand filtration: a report prepared by the task committee on slow sand filtration. new york: american society of civil engineers. 7. hendricks, d. (ed.). (1991). manual of design for slow sand filtration. denver: american water works association (awwa). 8. hendricks, d. w. and bellamy, w.d. (1991). “ microorganism removals by slow sand filtration”, in g.s. logsdon (ed), slow sand filtration: a report prepared by thetask committee on slow sand filtration. new york: american society of civil engineers. 9. li, g.b., ma, j. and du, k.y. (1996). “multi-stage slow sand filtration for the treatment of high turbid water”, in n. graham and r. collins (eds.), advances in slow sand and biological filtration. england: john wiley & sons ltd. 10. mcmeen, c.r. and benjamin, m. (1997). nom removal by slow sand filtration through iron oxide-coated olivine, journal of the american waterworks association, 89(2), 57-71. 11. poynter, s. f. b. and slade, j.s. (1977). the removal of viruses by slow sand filtration. progress in water technology. 9, 75-88. 12. riesenberg, f., walters, b.b., steele, a., and ryder, a.r. (1995). slow sand filters for small water system. journal of the american waterworks association, 87 (11), 48-56. 13. sims, r.c. and slezak, l.a. (1991). “slow sand filtration: present practice in the united states”, in g.s. logsdon (ed), slow sand filtration: a report prepared by the task committee on slow sand filtration. new york: american society of civil engineers. 14. weber-shirk, monroe l. and dick, r. (1997a). physical-chemical mechanisms in slow sand filters. journal of the american water works association, 89(1) 87. 15. weber-shirk, monroe l. (1997b) biological mechanisms in slow sand filters.journal ofthe american water works association, 89(2)72. 16. wheeler, d., bartram, j., and lloyd, b. (1988). the removal of viruses by filtration through sand. (as presented in slow sand filtration: recent developments in water treatment technology 1988 edited by n.j.d.grahamhalsted press: a division of john wiley & sons. 17. collins, m. r. 1998. “assessing slow sand filtration and proven modifications.’’ in small systems water treatment technologies: state of the art workshop. newwa joint regional operations conference and exhibition. marlborough, massachusetts. 18. collins, m. r. assessing slow sand filtration and proven modifications. in small systems water treatment technologies: state of the art workshop. newwa joint regional operations conference and exhibition. marlborough, massachusetts. 1998. 150 19. muhammad, n., parr, j., smith, m.d., and a.d. wheatley. removal of heavy metals by slow sand filtration. proceedings of the 23rd wedc international conference on water supply and sanitation, durban, south africa. (1997) 167-170. 20. stauber, c.e.,elliott, m.a., koksal, f., ortiz, g.m., digiano, f.a., and m.d. sobsey. characterization of the biosand filter for e. coli reductions from household drinking water under controlled laboratory and field use conditions. water science & technology. 54:3; 1– 7. iwa publishing (2006). shows the comparison between biosand filters (1 & 2) and previous works parameter biosand filter (r1) removal efficiency biosand filter (r2) removal efficiency previous works an indicator of fecal contamination > 91% > 81% > 97% (duke, 2006; stauber, 2006) protozoa and helminthes > 93% 90% > 99% (palmateer, 1999) viruses could not betested could not be tested 80-90% (stauber, 2005) organic and inorganic toxicants 56-81% 42-86% 50-90% (palmateer, 1999) iron 90-95% (ngai, 2007) most suspended sediments 98% 95% ------- shows the parameters limitations parameter limitations turbidity <1.0 ntu coliforms 1-3 log units enteric viruses 2-4 log units giardia cysts 2-4+log units cryptosporidium oocysts >4 log units dissolved organic carbon <15-25% biodegradable dissolved organic carbon <50% trihalomethane precursors <20-30% heavy metals zn, cu, cd, pb >95-99% fe, mn >67% as <47% 151 filtering systems plate (1) sand of plate (2) sand of plate (3) gravel effective diameter 0.35mm effective diameter 0.75mm layer material 152 effect of flow rate on removal of bod5 efficiency relationship between turbidity of influent water (ntu) and removal efficiency of trubidity 153 relationship between cod (mg/l) of influent water and cod removal efficiency for filters (r1 and r3) relationship between cod (mg/l) of influent water and cod removal efficiency for filters (r1 and r2) 154 effect of grey water temperature on bod5 removal efficieny relationship empty bed contact time (ebct) and water head per unit depth of sand (m/m sand ∆h/∆l) 155 effect of grey water temperature on relationship empty bed contact time (ebct) and cod removal efficiency \(microsoft word \\332\\346\\307\\330\\335 2\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 11 bending behavior of natural composites simply supported rectangular beams awatif mustafa ali mechanical .eng. dep. al-mustansiriya university abstract the central deflection of the composite simply supported beams is investigated in this research. fiber glass as a synthetic fiber , jute as a natural fiber as well as the egg shell ,starch as a powder, and coarse corn and tiny corn as a grains with polyester as a matrix are used to study the difference between the behavior of each type . in addition to, the effect of the moisture absorption is considered, so that the test specimens are immersed in distilled water and h2so4 for seven days .the results show that h2so4 has a significant effect on the flexural behavior(increase the deflection) of the beam .this is due to the chemical reaction between the polyester and h2so4. also, the variation of the central deflection with time under constant load is investigated. finally, from the load deflection relations the stiffness of each material is calculated as well as the modulus of elasticity are evaluated experimentally. keywords: composite plates, bending, moisture absorption. المركبة الطبيعية المواد دراسه سلوك االنحناء لصفائح عواطف مصطفى علي الجامعة المستنصرية/ كلية الهندسة / مساعد مدرس الموجز لصفائح مصـنوعة مـن البولسـتر المـدعم بأليـاف الزجـاج كأليـاف صـناعية وأليـاف ءلبحث تم اختبار االنحنافي هذا ا الجوت كألياف طبيعيه و قشور البيض والنشا كمسحوق إضافة إلى شعيرات الذرة الخشنة والناعمة استخدمت لدراسة ل علـى انحنـاء الصـفائح مثـل نسـبة امتصـاص اخذ بنظر االعتبار تأثير عدة عوام.اختالف سلوك االنحناء لكل نوع الرطوبة وتأثير الحوامض لذلك تم نقع العينات بالماء المقطر وحامض الكبريتيك لمدة أسبوع بينـت النتـائج أن النقـع ســلوك االنحنــاء بســـبب التفاعــل الكيمــاوي بــين الحـــامض زيــادة لمــدة أســبوع بحــامض الكبريتـــك لــه تــأثير كبيــر علـــى ثـم تـم حسـاب معامـل المرونـه . درس تغيير مقدار التشوه المركزي مع الـزمن تحـت تـاثير حمـل ثابـت كما. والبوليستر .والنعومة لكل ماده عمليا al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 12 introdction fiber reinforced polymer composites (frp) have been widely used to replace metal and wood because of their high specific tensile strength, good fatigue resistant, low density, reduced tool wear, enhanced energy recovery, good biodegradability and corrosion resistance, (varelidis, 1998). recently, there is the tendency of replacing synthetic fiber such as glass fiber with natural fiber for polymer composites. the reasons are mainly due to the low cost, sustainability and environmental issues (bradly, 1995). however, one of the main concerns of using natural fiber reinforced polymer composites is their susceptibility to moisture absorption which can affect the physical, mechanical and thermal properties (espert, 2002). the push for aerospace dominance that began in the 1950's and really picked up speed in the 1960's was a new impetus for composite development. richard young of the w. m. kellogg company began using filament winding for making small rocket motors. this technology was purchased by hercules and was the basis for the large-scale rocket motor business which was at the heart of the space race. by 1962 the need for highly accurate filament winding machine was improved and even more applications in aerospace were introduced. (crawford, 1998) generally natural fibers are classified into three categories; animal, vegetable and mineral fibers, as shown in figure a.1 among which mineral fibers are no longer or very rarely used due to their carcinogenic effect all vegetable fibers such as ,cotton, flax ,jute, hempetc contains (michael, 2002) .mainly cellulose and protein .these are the base of fibers with animal origin such as .hair, silk and wool. vegetable fibers are further classified into bast, leaf, or seed fibers according to their origin. the bast and leaf lend mechanical support to the plants s stem or leaf respectively; examples for these kinds of fibers include flax, hemp, jute and ramie. the surface of natural fibers are uneven and rough provides good adhesive to the matrix in a composites material .the specific mechanical properties of natural fibers have high significance for their utilizations in composites (michael, 2002). environmental factors such as humidity and temperature can limit the applications of sandwich structure composites by deteriorating the mechanical properties over a period of time. when a fiberreinforced composite sandwich structure is exposed to a hydrothermal environment and mechanical loads, changes in material properties are expected. these changes in material properties are connected to irreversible material strength degradation. exposure to water ambience induces environmental effects into both the core and the face sheet of sandwich structure (strength, 2010). ecological concern has resulted in a renewed interest in natural materials for their recyclables, light weight and non pollution. important issues such as recyclables and environmental safety need to be addressed when new materials and products are introduced. lignocelluloses natural fibers such as flax, hemp, sisal and jute are an interesting, environmentally friendly alternative to the use of glass fibers as reinforcement in engineering composites because of the benefits that these fibers provide over conventional reinforcement materials and the development of natural fiber composites has been a subject of interest for the past few years (liu, 2007). simply supported beams a beam is horizontal structural member that supported a vertical load. its length is much larger than its cross sectional area. for atypical beam ,the slender ratio sr ,is defined as the ratio of length(l) to the radius of gyration (r ).(sr=l/r) ; r= √i/a where (i) :moment of inertia and(a) beam cross section can be rectangular or a built section. beam are fabricated of steel, aluminum, concrete, wood and composite materials. they are used in buildings, bridges, aircraft, machinery, and other types of structures. a simple beam rests on 2 or fewer supports .a lentils place across the space between two columns is an example of a simple beam [8]. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 13 2. bending testing apparatus the bending testing apparatus used in this work is shown in figureb.1 below the materials used different types of natural and synthetic materials are used such that 1. fiber glass 2. tiny crushed corn 3. corn case 4. egg shell powder 5. jute fibers 6. crushed grain (coarse and tiny) 7. starch of corn these materials are used as the reinforcements with the polyester as the matrix to manufacture the composite plates. the steps of sample preparation manufacturing process for composite material preparing involves many techniques such as hand lay up, press molding, vacuum, etc. the step of preparation sample shown as the flow chart figure b.3 in this work we use first method (hand layup). : weight of the fiber, matrix and composite material respectively. : volume fraction of the fiber : volume fraction of the matrix v: volume fraction of the composite material : density of the fiber and matrix. : weight fraction. reslts discssion and conclsions the experimental results of the beam bending tests for many types of composites materials are carried out .to investigate the effect of the type of the reinforcement on the central displacement of the simply supported beam, different type of composite materials are used, such as ajute and corn bast (as natural fibers). bfiber glass as synthetic fibers. c-starch and egg shell powder as powder. dcorn grain (coarse and tiny). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 14 all these type of reinforcement mixed with the polyester as matrix with volume fraction 50% figure 1 to figure 7 show that : 1the fiber glass polyester is sustained higher load (31.5kg) before fracture while the jute polyester and the coarse corn polyester sustained lower load(5kg,3.5kg) respectively .it can be conclude that the synthetic fibers is more stronger than the natural fibers. 2the jute polyester and the corn bast beam have the higher displacement than the other types in which the maximum deflection at the fracture is (4.5mm) and (4mm) respectively, whereas the maximum deflection for the fiber glass is (2.6mm).that is the natural fibers is more elastic than the synthetic fibers. 3starch_ polyester has lower displacements (0.55mm) because in this case the properties of the polyester is dominate .i.e. the starch_ polyester material is brittle. 4the tiny corn is best than the coarse corn since, (is sustained higher load before fracture) otherwise the maximum deflection is inverse. considering the tiny corn specimens is more homogenous than the coarse corn specimen. 5from figure 6 it can be shown that the egg shell powder sustain higher load for the same deflection compare with coarse corn .this is due to the homogeneous of the egg shell . figure 8 shows that the comparison of bending behavior deferent type of test material .it can be seen that the fiber glass_ polyester is more stiffness than the other. effect of moisture on the deflection test in order to investigate the effect of moisture absorption .the test specimens are immersed in water and h2so4 acid for 7 days and under 80% of the fracture load for each type of test materials the results show that the water and h2so4 have evident effect on the central deflection of the beam. figure 9 show that the treat with water and without has the same effect on the fiber glass whereas figure 10 shows that the central deflection of the jute specimens is larger than the specimen with out treatment .this is may be due to that the moisture decreases the strength of the fiber, which is predominant in the beam specimen. figure 11 shows that the effect of water and acid on starch specimens. the water has a stronger effect on the specimens' .because of the water effect the bond of starch that effect leads to fracture after one minute. figure 12 shows that the effect of the water and acid on the first has same then water has greater effect on eggshell powder specimens figure 13 show that the water has stronger effect than h2so4 on the central deflection on the coarse corn .it can be seen that the water has hard coarse corn effect on corn. figure 14 shows that the water and acid are significant effect on the central deflection on the tiny corn .while figure 15 show that the acid and water have appositive effect on the corn blast composite and this is unexpected behavior may be due to inhomogeneous deflection increase with time specimen. references [1]bradly wl, grant ts.1995,"the effect of the moisture absorption on the interfacial strength of polymeric matrix composites". al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 15 [2]espert a, vilaplana f, karlsson s.2002, "comparison of water absorption in natural cellulosic fibres from wood and one-year crops in polypropylene composites and its influence on their mechanical properties" compos part a [3]michael k. bannister 2002,"3d fibres rienforced polymer composites", l.tong 3d fiber reinforced polymer composites. [4]r.j.crawford,bsc, phd, dsc, feng, fimeche, fim department of mechanical, aeronautical and manufacturing engineering the queen’s university of belfast 1998, plastics engineering third edition. [5]strength degradation of glass fiber reinforced polymer sandwich composites under hygrothermal loading conditions 2010. [6]varelidis pc, kominos np, and papaspyrides 1998, cd. polyamide coated glass fabric in polyester resin: interlaminar shear strength versus moisture absorption studies. composites. [7]x. y. liu*, g. c. dai 2007, surface modification and micromechanical properties of jute fiber mat reinforced polypropylene composites. [8]zaid rassim mohammed al-ani, beam flexural analysis of composite laminated simply supported rectangular sample of calclation ei wl 48 3 =δ (a) e= i lw 48 3 × δ (b) e=k i l 48 3 × (c) k= 210)150250( 81.9)23( ×− ×− i= 12 3bh =15 12 43 × =80 4mm l=16h=16 4× =64mm e=9.81 8048 643 × × =6.69mpa where k=stiffness (n/mm) e=modulus of elasticity (mpa) l=length of the sample (mm) h = height of the sample (mm) i=moment of inertia (mm 4 ). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 16 table 1 show (e, k) for the sample test figurea.1 classification of natural fibers [3] test sample modulus of elasticity (e) (mpa) stiffness value (k) (n/mm). fiber glass 44.63 78.1 jute 6.68 9.81 starch 51.5 91.56 corn blast 22.83 40.59 tiny corn 20.99 40.875 coarse corn 13.79 24.52 egg-shell 93.52 166.27 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 17 figure a.2 show the simply supported beam with concentrated load figureb.1 bending test apparatus figure b.2 bending specimen's dimension [8] al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 18 figure b.3 show the flow chart of the steps of the sample preparation calculate v calculate v f calculate v m calculate w m calculate w f polyester mixin g hardener liquid molding with brush mould preparation curing at room temperature for 24 hrs weighting calculateψ mechanical testing flexure testing al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 19 figure 1 the variations of the central displacements with load for fiber glass composite beam figure 2 the variations of the central displacements with load for jute composite beam. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 20 figure 3 the variations of the central displacements with load for starch composite beam. figure 4 the variations of the central displacements with load for tiny corn composite beam. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 21 figure 5 the variations of the central displacements with load for coarse corn composite beam. figure 6 the variations of the central displacements with load for egg shell powder composite beam. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 22 figure 7 the variations of the central displacements with load for corn bast composite beam. jute figure 8 the comparison of bending behavior for many types of composites materials and their modulus of elasticity (e) (mpa) and stiffness value (k) (n/mm). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 23 acid treatment water treatment with out treatment figure 9 the variation central deflection with time for fiber glass composites the variation acid treatment with out treatment water treatment figure 10 the variation of central deflection with time for jute composites al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 24 figure 11 the variation of central deflection with time for starch composites figure 12 the variation of central deflection with time for egg shell composites al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 25 with out treatment acid treatmentwater treatment figure 13 the variation of central deflection with time for coarse corn composites with out treatment water treatment acid treatment figure 14 the variation of central deflection with time for tiny corn composites al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 26 acid treatment with out treatment water treatment figure 15 the variation of central deflection with time for corn blast composites template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 147 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. design of intelligent pid controller based on modified swarm techniques ahmed kareem abdullah, al-furat al-awsat technical university, al-mussaib technical college, babel, iraq email: ahmed_albakri1977@yahoo.com received on 27 october 2016 accepted on 31 january 2017 . abstract: the swarm techniques are used widly to enhance the response of the control system, but there are many drawbacks appear when these techniques are used to select the initial solution for the problem and then will referect on the overall convergence. this paper try to solve this problem by modify the initial solution of particale swarm techniques based on fast genetic algorithm, the modified pso make good free searching in candidate solutions to get optimum suggesions, which leads the algorithm towards the global optimum searching over wid range. the proposed controller named pso-fga-pid controller and two experiments are tested by this controller to check the proposed work, first one the linear time invariant system is taken and the second one is to control on the speed of the dc motor. keywords: particle swarm optimization, genetic algorithm, linear time invariant system, intelligent controller 1. introduction the artificial intelligence (ai) algorithms consist of evolutionary computation (ec) and swarm intelligence (si) [1]. the ec technique based on the biological evolution principles while the si technique based on the swarm behavioral patterns. , the artificial intelligence techniques used to solve many complex control problems. many researchers deals with the hybridization of intelligent technique with pid controller to enhance the overall responses, w. meng 2015, used adaptive neural control to investigate and enhance the mimo nonlinear with time-varying system, the weight of single neural network is online tuned estimated the unidentified functions in the dynamics of the system also the singularity of the coefficient is escaped without prior knowledge [2]. j. murphy and s. godsill 2015, demonstrate an efficient method for conditionally and estimation the matrix of the time-varying system parameters based on the inference of time-varying parameter vector auto regression system [3]. many methods used to tune pid parameters and set gains, such as ziegler-nichols, cohen-coon, and chien-hrones-reswick [4]. this paper focuses on the pso and sga as important artificial intelligent techniques used to enhance the response of linear time invariant system lti and dc motor speed control by tuning the pid gains. 2. artificial intelligent techniques evolutionary computational techniques (ec) based on the biological philosophies and swarm intelligent (si) techniques based on swarm social [1]. mailto:ahmed_albakri1977@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 148 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.1. evolutionary computation (ec) ec algorithms are inspired by biological concepts such as population, crossover, and mutation. ec are stochastic examine techniques that modeled the system in standard selection and growth in the biological system [5]. the ec techniques categorized into several algorithms genetic programming (gp), evolutionary programming (ep), evolutionary strategies (es), and genetic algorithm (ga) as mentioned in [6, 7]. 2.2. swarm intelligent (si) si algorithms established on the analysis of the routine of a collection in regionalized the swarm system. si is naturally organized the local of the tested group with the main location. ant colony optimization (aco) and particle swarm optimization [5] represent important techniques in this field [8]. 3. comparison between ga and pso in recent years and from earlier analysis of the intelligent techniques confirmed that the pso is better than ga when used to analysis the system. some significant landscapes for pso compared with ga are registered below [5]: the pso is faster than ga. the pso is robust and its performance better than ga. the routine of pso is unfeeling to the size of the population. the obtained solutions by pso are more stable. the calculations in pso is less than the calculations in ga. even though ga has been usually used to resolve the optimization problems in many field, but ga steps needs more calculations to access the goal. as well as the decrease of the convergence of ga reduces the performance of the system and decreases the abilities of the system to search the optimum solution. pso algorithm give the best solution in a little calculation also the obtained results are more stable compared with any stochastic techniques. 4. proposed controller (pso-fga-pid) in this section, the controller is described in details: the pid is used to improve the response by adjust the error between actual output and required input. the control action signal which is created by weighted sum of the pid actions as shown in figure 1 [4]. p  input figure 1. the system with a pid error e(t) i plant output d  _ al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 149 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the output or control action signal of pid is ruled by: (1) fast genetic algorithm (fga) is a stochastic founded on biological development field [9]. in each loop a fresh solution or children is formed which will perfectly have better fitness than the former solutions. fitness refers to how well a solution acts in the problem domain [10]. fga is a vectored execution of ga in matlab without bells. ga parameters are [11]: max. no. of gen. = 40; population size = 30; the length of chromosome =3; the crossover probability = 0.95; the mutation probability of = 0.05; type of selection is roulette wheel selection; type of crossover is single point; type of mutation is real, the fitness is ruled by : (2) integral of square error (ise) is used as optimization condition in this algorithm. the epsilon ( ɛ ) is very small constant (0.0001) added to ise in the denominator of the fitness function to avoid the infinity value. the chromosome representation of the proposed algorithm is shown in figure 2. the control parameters set k= (kp, ki, and kd) are observed as a position p = (p1, p2, and p3) of a particle in a 3-dimensional field [6]. if the number of particles is l in a generation, the technique of the suggested pso-fga-pid controller can be designated by: set the pso parameters: particles’ number (l), iterations’ number (n=50), range of search, the constraint of velocity, and the constants c1 = c2 = 2. set the generation (g =1) for the initial generation and produce the particles from fast genetic algorithm as above compute the fitness for the particles in the generation and govern the position of the particle with the greatest fitness. calculate the (q) of the particle with the maximum fitness. if generation index g > n, then go to the end. and then, go to next step. tuning the velocity values for the particles and form the velocity. tuning the position values for the particles and bound the new position values for particles regulate the controller based on the gotten parameter set (pbest) with the best fitness (fbest). the velocity and position are calculated: the flowchart of the pso-fga-pid is illustrated in figure 3. kp ki figure 2. chromosome representations in pso-fga-pid controller kd al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 150 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. start end the best solution (kp, ki, kd ) from ga represent the initial searching field for pso. the gains k= (kp, ki, and kd) are represented by the positions p = (p1, p2, and p3) of the element in a 3d field and then calculate the initial velocities, positions, pbests, and gbest. compute the fitness function choice the pbest and gbest recalculate the velocities and positions best pid gains checking figure 3. flowchart of the proposed controller pso-fga-pid yes no no stopping criterion (no. of generati on) calculate the fitness function for each chromosome by eq.2 selection, crossover, and mutation get best solution for pid parameters (kp, ki, kd ) and obtain the system responses yes call pid controller call pid controller increase gen. initialize ga parameter pc, pm, pop, maximum no. of generation, and generate initial population al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 151 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. results 5.1. benchmark 1: linear time invariant system (lti) to verify the efficiency of the proposed controller, the following time invariant system is taken [12]. figure 4 shows the block diagram of the system with pid. the simulated system in matlab is represented in figure 5. figure 5. plant model representation from matlab-simulink figure 4. block diagram of feedback control system with a pid controller simulated by matlabsimulink al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 152 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the responses of the lti system with different controllers are shown in figure 6. the system has been subjected to a internal sudden large disturbance as shown in figure 7 at the terminal to test the proposed controllers. the scope signals are shown in figure 8. in order to emphasize the advantages of the proposed controllers, the system with conventional pid and without any controller are implemented for comparison. table 1 illustrates the performance index (ise) and pid parameters for the linear time invariant system without controller, with conventional pid, fga-pid controller, and pso-fga-pid controller. figure 6 . the responses of lti system (a) without controller (b) with pid controller (c) with fga-pid (d) with pso-fga-pid (a) (b) (c) (d) time time time time o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 153 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 7. simulation of system subjected to a disturbance 5.2. benchmark 2: dc motor speed control [13] the motor is categorized into: dc & ac motor, these groups have different types and each one givs unique soultions for particular requests. the design requirements are: overshoot ≤ %5 , settling time ≤ 2 seconds, and steady state error ≤ 1%. the general schematic diagram for the dc motor is represented by the figure 9 [13] (a) (b) (c) (d) figure 8. the responses of lti system with sudan change (a) without controller (b) with pid controller (c) with fga-pid (d) with pso-fga-pid time time time time o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 154 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 1. performance index, pid parameters, and time response parameters the motor parameters are: moment of inertia (jm)=0.01kg × m2/s2 ; r =1ω; l=0.5h; constant of electromotive force kt=0.01nm/amp; constant of motor viscous friction (beq)=0.1nms; 1000 rpm dc motor. these parameters may be changed based on the torque & rpm. the transfer function of the motor is determined based on the figure 10. type of controller ise time response parameters tr tp o.s tss without controller 48.316 0.033 0.051 2.901 0.21 pid 5.3161 0.032 0.055 1.203 0.13 fga-pid 1.2011 0.039 0.071 0.19 0.06 pso-fga-pid 1.0936 0.038 0.082 0.09 0.05 figure 9. the schematic of the dc motor figure 10. feedback dc motor control system simulated in matlab simulank al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 155 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the dc motor transfer function is: (9) the responses of the dc motor with different controllers are shown in figure 11. table 2 illustrates the ise and pid parameters for the dc motor speed control system for different controllers. 6. conclusions the duty of the swarm technique is to enhance the output response of the systems by tuning the pid gains until reach to the specific conditions. the paper is focused on the pso as intelligent computational technique for tuning pid parameters and compared with another intelligent technique fga. the objective has been to enhance the performance of the response of lti system and dc motor speed control, that experience very poor control behavior with conventional tuning methods. the proposed controller is proposed based on hybridiz of two intelligent techniques with conventional pid. intelligent-pid controllers are solved many difficulties, but they are little complicated in a computation. the fitness function based on ise is very efficient criteria. the tuning of pid parameters have a significant effect on the system response, therefore the best choose is generated and tuned randomly by the proposed algorithm. finally, the results obtained by the proposed controllers are encouraged. figure 11 . the responses of dc motor system (a) without controller (b) with pid controller (c) with fga-pid (d) with pso-fga-pid (a) (b) (d) (c) o u tp u t re s p o n s e o u tp u t re s p o n s e time time time time al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 156 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 2. performance index, pid parameters, and time response parameters 7. acknowledgment thanks to al-furat al-awsat technical university to support this research and i would like to express my thanks to amin noshadi/ college of engineering and science, victoria university, australia to support and help me by codes. references 1. engelbrecht. a.p., computational intelligence: john wiley and sons, 2002 2. meng w., qinmin yang m., and sun y., "adaptive neural control of nonlinear mimo systems with time-varying output constraints," ieee transactions on neural networks and learning systems, vol. 26, 2015. 3. murphy j. and godsill s., "efficient filtering and sampling for a class of time-varying linear systems," presented at the 2015 ieee international conference on acoustics, speech and signal processing (icassp), , south brisbane, qld, 2015. 4. yi t. q., kasilingam g., and raguraman r., "effect of pid power system stabilizer for a synchronous machine in simulink environment,"presentedat the 4th international conferenceon energyand environment 2013(icee2013), 2014. 5. pillay n., "a particle swarm optimization approach for tuning of siso pid control loops " master, department of electronic engineering., durban university of technology., 2008. 6. rahimian m. s. and raahemifar k., "optimal pid controller design for avr system using particle swarm optimization algorithm," presented at the electrical and computer engineering (ccece), 2011 24th canadian conference on, niagara falls, on, 2011. 7. al-awami a. t., abdel-magid y. l., and abido m. a., "a particleswarm-based approach of power system stability enhancement with unified power flow controller," electric power and energy systems, vol. 29, pp. 251-259, 2007. 8. dorigo m. and g. l.m., "ant colony system: a cooperative learning approach to the traveling salesman problem," ieee transactions on evolutionary computation, pp. 53-66, 1997 9. mohammed n. f., x. ma, and song e., "tuning of pid controller for diesel engines using genetic algorithm," in 2013 ieee international conference on mechatronics and automation (icma), japan 2013, pp. 1523-1527. type of controller ise time response parameters tr tp o .s tss without controller 4.234 0.41 0.45 0.12 1.2 pid 2.178 0.53 0.55 / 1.3 fga-pid 1.927 0.67 0.21 0.12 1.2 pso-fga-pid 1.298 0.69 0.19 0.09 1.1 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 157 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 10. kumar b. r., murali m., kumari m. s., and sydulu m., "short-range fixed head hydrothermal scheduling using fast genetic algorithm," presented at the industrial electronics and applications (iciea), 2012 7th ieee conference on, singapore, 2012. 11. mitchell m., an introduction to genetic algorithms: mit press, 1996. 12. noshadi a., shi j., lee w. s., shi p., and kalam a., "optimal pid-type fuzzy logic controller for a multi-input multi-output active magnetic bearing system," natural computing applications, springer 2015. 13. temel s., yağli s., and gören s., "discrete time control systems, p, pd, pi, pid controllers," middle east technical university; electrical and electronics; engineering department2010. 1-2-2011.pdf بتس على )(٠علیها )٣٠(% )٤٥، ٣، ٢، ١ () ( . )٧٢٤ .(% : ٠ al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 14 rehabilitation of damage reinforced concrete columns dr. adnan s. al-kuaity college of engineering university of kufa abstract in order to restore the strength of failed reinforced concrete columns, the cracked shell was replaced by new materials of repair: plain concrete, fiber-reinforcement concrete and cementmortar alternatively. three groups of reinforced concrete squared tied columns were tested concentrically. the columns were short-columns reinforced with 2% longitudinal steel reinforcement ratio. behavior of repaired columns have been presented by measuring concrete surface strain with axial load up to cracking load. effects of both concrete compressive strength of materials of repair and preloading on the restoring column strength have been established. test results have ,also, shown that the strength of failed column can be restored by replacing the cracked shell with new shell having high compressive strength. the strength of columns repaired by these materials can reach up to 136% of their original strength depending on both the compressive strength and the condition of preloading. furthermore ,axial strength of repaired columns was derived by modifying the equation given by aci-code for calculating design axial load strength of reinforced concrete column. . keywords: columns, fiber, failure load, reinforced concrete, repair الفاشلةخرسانیة المسلحةأعادة تأھیل األعمدة ال عدنان صادق الكویتي. د جامعة الكوفة–كلیة الھندسة الخالصة . المت شققة الخارجی ة الق شرة وذالك باستبدال الفاشلةالمسلحة یھدف ھذا البحث إلى دراسة إمكانیة استعادة مقاومة األعمدة الخرسانیة الخرس انة اللیفی ة ، مون ة ال سمنت , م ادة الخرس انة : صلیح إال وھ ي ت صبھا باستخدام ثالثة أن واع م ن م واد ال إعادة و األعمدة لھذه لق د كان ت األعم دة . اجري الفحص على ثالثة مجامیع من األعمدة المسلحة ذات المقطع المربع وذلك بتحمیلھا محوری ا . على التوالي درس سلوك ھذه األعمدة من خ الل قی اس االنفع ال ال سطحي %. 2 القصیر والمسلح بالقضبان الحدیدیة طولیا بنسبة تسلیح من النوع .إثناء التحمیل ولغایة مرحلة الفشل . لمؤھل ة التصلیح وكذلك تأثیر نسبة التحمیل قبل التصلیح على مقاومة األعمدة الخرسانیة اةتم في ھذه الدراسة بیان تأثیر مقاومة ماد لقد بینت نتائج الفحص إن من الممكن استعادة مقاومة األعمدة الخرسانیة الفاش لة بت شقق ق شرتھا الخارجی ة وذال ك بواس طة اس تبدال م ن % 135القشرة الخارجیة بم واد خرس انیة عالی ة المقاوم ة حی ث أظھ رت النت ائج إن باألمك ان تحقی ق زی ادة بالمقاوم ة ت صل إل ى .ة قبل الفشل ویعتمد ذالك على مقاومة مادة اإلصالح وعلى حالة التحمیل التي أدت إلى الفشلالمقاومة األصلی إضافة إلى ما جاء أعاله فان ھذه الدراسة تق دم معادل ة نظری ة الحت ساب مقاوم ة األعم دة الخرس انیة الم سلحة الفاش لة بع د إص الحھا . اعتمادا على معادلة الكود األمریكي al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 15 nomenclature ac = cross sectional area of concrete. as = cross sectional area of steel. acr = cross sectional area of original concrete core. ash = cross sectional area of outer shell. f'c' = concrete compressive strength. fy = yield stress of steel reinforcement. f c s h = compressive strength of the new shell. k = factor related to creep and rate of loading. p = load exerted on reinforced column before repair. pu = axial ultimate load of reinforced concrete column before repair. pur = axial ultimate load of reinforced concrete column after repair. introduction in reinforced concrete column, the outer concrete shell has a significant contribution in carrying the design loads. such contribution may reach up to 40% of the ultimate loads, especially, in column having small cross sectional area (less than 900cm2).this can be simply determined using equation derived by (richart and brown,1934). on the other hand, the outer shell acts to protect the steel reinforcement against corrosion and fire attack. therefore any damage or cracks in the outer shell will affect seriously both the strength and performance of the column. in practice, the column is considered to be reached its own maximum carrying capacity when the outer shell starts to spall off (at spalling load). the ultimate load in tied column is nearly equal to the spalling load, whereas, it may be more than that in spiral column. generally a complete failure in reinforced concrete column takes place when the concrete fails by crushing or shearing outward along inclined planes and the longitudinal steel fails by buckling outward between (richart and staehle,1931). partial cracking of outer shell may also occur due to different causes, such as earthquake, fire attack, end of design age of column…etc. in any case, the presence of partial spalling in concrete column does not mean that the column has a complete failure, but is ultimate capacity is reduced and it may no longer be considered serviceable. however, proper repairing of spalled shell can restore or even increase its original ultimate capacity. repair of cracked shell of column can be commonly made by jacketing technique. this includes casting new reinforced concrete shell around the damage column. the new concrete can be preplaced aggregate concrete or normally placed concrete. these techniques are often used for both retrofitting and strengthening of reinforced concrete column (suleiman,1991&ersoy et al,1993). there are many factors affecting the strength of the repaired column such as the strength, shrinkage and creep of both old and new concrete. however, the problem of repairing involves many uncertain factors which have not yet been fully investigated. the primary objective of this research is to restore the ultimate carrying capacity of spalled column without increasing its original size by using three types of material of repair (plain concrete with 12mm maximum size of aggregate , fiber reinforced concrete and cement mortar). effect of both instaneous preloading and the compressive strength on the strength of repaired column were also investigated. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 16 theoretical consideration numerous careful test (richart,1934 and aci 318-02) have shown the ultimate load of a concentrically loaded reinforced concrete column is reached when the concrete crushes while the steel yields satisfying the following equation: pu = 0.85 fc' ac + fy as (1) where: pu = ultimate load. f'c' = concrete compressive strength. ac = cross sectional area of concrete. fy = yield stress of steel reinforcement. as = cross sectional area of steel reinforcement. equation (1) was modified here to take into account the contribution of replaced outer shell. this can be done by partitioning the first term of the right-hand side of equation(1) , (0.85 fc' ) into two parts as: k ash f'csh = compressive strength of the outer shell k acr f'c = compressive strength of inner core when the outer shell of column is replaced by new concrete shell after repairing. the total ultimate load of repaired column (pur) can be expressed here as: pur = k [ash f'csh + acr f'c] + as fy (2) where: k = factor related to creep and rate of loading. ash = cross sectional area of outer shell. f c sh = compressive strength of the new shell. acr = cross sectional area of original concrete core. the bond between old concrete and new concrete shell was secured by roughing the old concrete face to have a full amplitude of approximately 5mm (as recommended in article 11.7.9, aci-318 02 code). this type of bond is interlock type of bond between old and new surfaces of concrete. when the concrete core and outer shell cast monolithically, (as the usual case in practice), k is equal to 0.85 as given by (aci-318 02 code ). in case of column with repaired shell, (k) may be evaluated from test results taking in consideration the effect of creep and shrinkage in both the old concrete core and new outer shell as carried out later in this investigation. experimental investigation to study the possibility of restoring the ultimate capacity of spalled shell column, three groups (a,b,c) of reinforced concrete squared tied columns were considered. the cross sectional dimensions of each column was 150mm x 150mm with 900mm length. each column is reinforced with 4-12mm diameter longitudinal bars and 6mm diameter at 200mm transverse ties [figure:(1)]. the yield stress of steel reinforcement used for both longitudinal and transverse reinforcement was obtained from test to be 270 n/mm2. the compressive strength (f'c') of all columns were about 12n/mm2. such low yield stress of steel reinforcement and low concrete compressive strength used in specimens to stimulate those columns which have been widely constructed in most building during sixties and seventies of the past century and their compressive strength may be deteriorated due to carbonation and other climate conditions. furthermore ,most of the old al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 17 reinforced concrete buildings in the developed countries have been built with low material strength. however, group (a) consist of six identical basic columns which belongs into three couples. the first couple were loaded concentrically to the spalling load and it is stopped when the outer shell started to spall off. this load is considered to represent about 100% of the ultimate load. the second couple were loaded in similar way to about 75% of the ultimate load. these types of loading are called preloading in this investigation. the third couple have been left without loading (0%). then the outer shell of all columns were removed [figure:(9)] by chisel making the concrete surface rough with a full amplitude of approximately 5mm. in order to insure good repairing and to restore the original strength capacity of damage column, plain concrete with high compressive strength was used to replace cracked shell. the average thickness of new shell in the specimen tested here is about 25mm as shown in figurel1). the average compressive strength of about 45.8n/mm2 was used in this group. the proportion of concrete mix used for repair was 1 cement : 1sand : 1.5 gravel (by weight) with maximum size 6mm. water-cement ratio in this mix was 0.37 .to increase workability ,water reducing agent (feb-flow) was added to the mix by amount of 2.5 kg/m3. details of test specimen are shown in figures: (5),(6),(7). group b and c are similar to group a except, the materials of repair used for the outer shell were reinforced fiber concrete and cement mortar respectively. the average compressive strength of shell materials of group b and group c were 51.2n/mm2 .the reinforced fiber concrete was made of similar concrete mix as in group a. the fibers were high yield strength, deformed and brass coated. they were 45mm long and o.5mm diameter with aspect ratio of 90 . 1behavior of test columns all columns were tested concentrically after repair figures:(6),(7),(8),(9),(10). the test results are given in table(1). during tests, the compressive strain was measured at each load increment until the concrete shell started to crack. the average value of test results of each couple of columns were recorded. the load concrete strain curves for repaired columns, (loaded to cracking load before repair), are shown in figure: (2). the behavior of repaired column under load can be summarized: 1-the columns after repair show similar behavior compared to the original columns before repair. 2-slight increase in the stiffness of repaired columns were observed relative to the original column. this may be attributed to the high compressive strength of the outer shell which increase the modulus of elasticity. 3-repaired columns show higher spalling load (with sudden and brittle cracking of the outer shell) than those of original column. gradual cracking was observed for columns repaired by fiber reinforced concrete. 4-the cracking load of repaired columns is higher than that of original column with range of about 5% to 27% depending mainly on the compressive strength of the outer shell. 2 effect of preloading figure:(3) shows that there is a slight consistent decrease in the relative spalling load (pur/pu ×100) due to increase in the relative preloading percentage (p/pu). such behavior is similar for the three types of repairs( plain concrete, fiber reinforced concrete and cement mortar). the decrease in the relative spalling load is ranging between about 5% in columns repaired by cement mortar to about 10% in columns repaired by plain concrete. this decrease may be attributed to the effect of restrained shrinkage in the new shell besides the effect of preloading on the original core. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 18 tests by rusch and others have shown that for concentrically loaded, un reinforced concrete prisms or cylinders, the strength under sustained load is significantly smaller than fc’, of the order of 75percent of fc’ for loads maintained for a year or more (winter&nilson,1972). however, instantaneous preloading, in this investigation, has clearly reduced the spalling load of columns repaired by plain concrete, fiber-reinforced concrete and cement mortar. 3effect of compressive strength figure (4) indicates that the increase in the compressive strength of the outer shell resulted in considerable increase in the relative spalling load. this relationship is similar in pattern for the three types of repair. the relative spalling load increased to about 25% when the compressive strength increased to about 38%. the compressive strength of outer shell was observed to be the major factor affecting the strength of repaired column. 4evaluation factor k based on figure (4) the spalling, load seems to be not directly proportional with the compressive strength of the outer shell as given by equation (2). this is mainly because of the effects of preloading and restrained shrinkage of the new shell (suleiman,1991). these effects can be taken in consideration through evaluating the factor k from test results of this investigation as: k =0.39–0.0005 p/pu for plain concrete shell and fiber reinforced concrete k =0.33–0.0006 p/pu for cement mortar shell effect of creep can also be included when test results are available. using equation 2 with the above imperical values of k, the spalling load can be predicted for repaired reinforced concrete column. conclusions 1. it is possible to restore the ultimate capacity of concentrically loaded column by replacing the outer spalled shell with new one having high compressive strength. plain concrete, fiber reinforced concrete and cement mortar can effectively be used for this purpose but the fiber reinforced concrete may have the best results. 2. the spalling load of repaired columns is adversely affected by the instantaneous preloading. 3. the compressive strength of the material of repair was observed to be the major factor affecting the spalling load of the repaired column. 4. the proposed equation (1) can be modified to include the effect of creep to be used for predicting the ultimate capacity of column after repair. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 19 references [1] aci 318-02 “building code requirement concrete: american concrete institute, 1989. [2] ersoy, u, tankut, t and suleiman, r. “behavior of jacketed columns” aci jr. may-june 1993 pp. 288-293. [3] richart, f. e. and brown, r.l. “an investigation of reinforced concrete columns” univ. illinois eng. exp. sta. bull. 267, 1934. [4] richart, f. e. and staehle, g. c. “column tests at university of illinois” jr. aci, 2, feb., mar. 1931; proc, 27, pp. 731-761; jr.3, nov. 1931, jan. 1932 proc, 28pp. 167-279. [5] suleiman r. e. “repair and strengthening of reinforced concrete column” ph.d thesis, middle east technical university, 1991. 186 pp. [6] winter, g. nilson, a. h. “design of concrete structures” mcgraw-hill book company 8th ed. 1972. table (1) test results group material of repair column load before repair (p/pu×100)* spalling load after pur (kn) a1 0 380 a2 75 355.4 a plain concrete a3 100 347.6 b1 0 391.4 b2 75 376.7 b fiber reinforced concrete b3 100 366.4 c1 0 307.5 c2 75 301 c cement mortar c3 100 292.3 *p = applied load before repair. pu= average spalling load obtain from specimens a3, b3, c3 before repair. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 20 figure(2): load-axial strain curve of concrete column under axial load with three types of repair al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 21 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 22 figure (5) : forms and steel reinforcement figure (6) : experimental setup of test of test specimens specimen figure (7) : typical specimen (a2) under figure (8) : initiation of 1st crack in specimen loading at 70% of ultimate load a2 a2 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 23 figure (9) : removing of cracked shell of figure (10) : testing of a2 after repair up specimen a2 failure a2 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 51 numerical simulation of natural convection in a laminar two – dimensional flow through a vertical rectangular duct. abstract this research uesd to compute the flow field variables of natural convection air flow based on finite difference computational fluid dynamic methods. the problem considered deals with a twodimensional internal, laminer , isothermal flow over a vertical rectangular duct. in this work, governing equations were solved using finite different forward explicit technique. the flow characterstics are evaluated for prandtl number at 0.7 and dimensionless inlet velocity equals to 0.005. the results explain that the heat transfer rate is a strong function of flow velocity also the hydrodynamic properties such as pressure, temperature and velocity are increased when the flow moves upward the duct.the results showed a good agreement with other published results. key word: natural convection , cfd , vertical duct , buoyancy-induced flow. المحاكاة العددیة للحمل الحر لجریان طباقي ثنائي البعد خالل نفق عمودي مستطیل المقطع :الخالصة التي تم دراستها تتعلق المسألةفي هذا البحث تم حساب متغيرات جريان الهواء بالحمل الحر اعتمادا على طرق الفروق المحددة في هذا البحث المعادالت الحاكمة تـم . رارة فوق مجرى عمودي مستطيل الشكلبجريان ثنائي البعد داخلي طباقي متساوي الح وسـرعة 0.7 خواص الجريان تم حسابها لرقم براندل يـساوي (space marching).حلها بواسطة تقنية المتغير المكاني دالة لـسرعة الجريـان وأيـضا النتائج أوضحت بأن معدل انتقال الحرارة هو . 0.005الجريان الالبعدية عند المدخل تساوي النتـائج . كالضغط ودرجة الحرارة والسرعة تزداد عندما الجريان يتحرك باتجـاه أعلـى المجـرى الخواص الهيدروديناميكية .أوضحت تطابق جيد مع النتائج األخرى المنشورة dr. ahmed kadhim hussein college of engineering babylon university mechanical engineering dep. dr. hayder shakir abdulla college of engineering al-qadisiya university mechanical engineering dep. dr.abbasa.s. al-jeebori college of engineering al-qadisiya university mechanical engineering dep. عباس علیوي الجبوري. د القادسیة جامعة –كلیة الھندسة قسم الھندسة المیكانیكیة حیدر شاكر عبد اهللا. د القادسیة جامعة –دسة كلیة الھن قسم الھندسة المیكانیكیة أحمد كاظم حسین. د جامعة بابل–كلیة الھندسة قسم الھندسة المیكانیكیة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 52 list of symbols: symbol description dimension cp specific heat at constant pressure. kj /kg.k gr grashof number. grw grashof number based on duct width. g acceleration due to gravity. m/s2 e specific internal energy per unit mass. j/kg h dimensionless duct height. h duct height. m k thermal conductivity . w/m.k p dimensionless pressure. p pressure. n/m2 pr prandtl number. q dimensionless heat transfer rate. q heat transfer rate per unit area. w/ m2 t temperature. c u dimensionless velocity component in z-direction. u velocity component in z-direction. m/s uav dimensionless average velocity at any section of the duct. uav average velocity at any section of the duct. m/s v dimensionless velocity component in y-direction v velocity component in y-direction. m/s w duct width m y coordinate in horizontal direction. m z coordinate in vertical direction. m greek symbols β coefficient of thermal expansion. k-1 θ dimensionless temperature. µ dynamic viscosity. n.sec/ m2 υ kinematic viscosity. m2/s ρ density. kg/m3 zy ∆∆ , spatial steps in computational domain. subscript i, j node symbols indicates position in z and y directions respectively. ∞ conditions at free stream. w conditions at surface. av average. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 53 introduction a natural convection flow field is a flow driven by the presence of a temperature gradient.as a result of the temperature difference, the density field is not uniform also.buoyancy forces will induce a flow current due to gravitational field and the variation in the density field. in general , a natural convection heat transfer is usually much smaller compared to a forced convection heat transfer .it is therefore important only when there is no external flow exists . for example in fluid flow through ducts , solar energy collectors, enclosures and spheres martynenko and khramtsov (2005).in the present study ,natural convection due to the laminer flow through a rectangular vertical duct was investigated . such a case occurs in a number of situations involving the cooling of electrical and electronic equipments, also in the flow through a certain types of fin arrangement.during the past, the experimental and analytical methods were used to simulate the free convection over a limited number of shapes.ortega and moffat (1986) studied natural convection from an array of cubical elements in a channel flow.they concluded that the superposition technique could be used to predict temperatures in a free convection channel flow.pu etal. (1999) presented an experimental results of mixed convection heat transfer in a vertical packed channel with a symmetrical heating of opposite wall.a correlation equation for the nusselt number in terms of peclet number and rayleigh number was obtained from the experimental data.cadafalch etal. (2002) used a finite volume numerical computation in order to obtain a correlation for the heat transfer in a large air channels considering radiative heat transfer between the plates with different inclination angles.guimaraes and menon (2004) studied free and forced convection in an inclined rectangular channel. the system of governing equation was solved using the finite element method . they observed that the inclination angle has a stronger effect on the flow and heat transfer for low reynolds number.bain and armfield (2004) applied a collocation scheme to vertical natural convection problem.marginal stability curves and critical heat fluxes are obtained for prandtl numbers from 0 to 1000. comunelo and guths (2005) examined the heat transfer coefficient of an isothermal vertical plate.they used novel technology to measure heat flux.the results expected that an increasing of heat transfer coefficient was very useful in heat exchange devices.abid etal.(2006) studied the free and forced convection in a horizontal vertical duct of transversal aspect ratio close to 2.0 uniformally heated from below and thermally insulated else where.they noticed that the heat flux supplied to the wall induces a secondary flow which manifests itself through natural convection rolls.in this work, a numerical simulation gives the results with a short-time and an accurate computation and the computer program may be changed easily to deal with any other complex shapes such as enclosures, sphere and circular ducts.in the numerical simulation, the governing differential equations are overcame by replacing it with differences, calculated from a finite number of values associated with the computational nodes, which are distributed on a suitable grid over the solution domain. in the present study, the explicit space marching finite difference method was adopted to predict the free convection characteristics of two-dimensional internal laminer isothermal flow over a vertical rectangular duct to compute the primitive variables such as the velocity, pressure and temperature at each grid.in the next section, the mathematical analysis will be given in detail and the style, which used to solve the governing equations was described. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 54 mathematical analysis the studied case is a natural convection flow of air which passes through a vertical rectangular duct with height ( h ) and width ( w ) and the problem considered is described schematically as shown in figures ( 1 and 2 ). the inlet and exit sections of the duct are open to ambient. the flow creats since the walls of the duct are at different temperature from that of the fluid which surrounds the duct , so it is described by continuity,momentum and energy equations. these equations are written in a dimensionless form by dividing all dependent and independent variables by suitable constant terms. the solution is obtained using explicit space marching finite difference technique and the following assumptions are considered: 1. the velocity at inlet section of the duct is considered uniform and equals to the flow average velocity uav. 2. the flow enters the duct through a smooth inlet so the viscous forces are neglected. 3. the flow is considered steady , two-dimensional , moving upward through the duct and symmetrical about the duct center line ( solution from y = 0 to y = w / 2 ). 4. no heat transfer occurs to the entering fluid and the fluid is at atmospheric temperature and the duct walls are heated to the same uniform temperature also all the viscous dissipation and radiative transport are neglected. 5. the duct width ( w ) is considered very small compared with its height ( h ). 6.the flow is considered laminer, since the duct is short and the driving temperature is not too high. 7. density variations are related only to the buoyancy terms of the momentum equations ( boussinesq approximation) and all the thermophysical properties are assumed to be constant. 8.air flow is entering the vertical duct from below ,such that only the buoyancy force is aiding the flow. the governing equations for a two-dimensional, steady, laminer, internal flow expressed in conservation form are: continuity equation: 0 yz = ∂ ∂ + ∂ ∂ vu (1) the conservation of momentum equation in z-direction : g y u dz dpu v u u ρµρρ − ∂ ∂ +−= ∂ ∂ + ∂ ∂ )( yz 2 2 (2) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 55 the conservation of energy equation is : ))(( 2 2 y t c k y t v z t u p ∂ ∂ = ∂ ∂ + ∂ ∂ ρ (3) the average heat transfer equation rate oosthuizen and naylor ( 1999) is dyttuc z q w pa v )( 1 2/ 0 ∞−= ∫ ρ (4) the boundary conditions used in the present study can be arranged as follows: 1.since the flow is symmetrical about the center line,so at y = 0.0 0.0 y = ∂ ∂u and v = 0.0 , 0.0 y = ∂ ∂t (5) 2.near the wall of the duct ( w / 2) at y = w / 2 then u = 0.0 v = 0.0 and t= t w (6) 3.at inlet plane of the duct ( z=0.0) at z = 0.0 then u = u av ∞= tt and 0.2 2 a vupp ρ −=− ∞ (7) 4.at exit plane of the duct ( z = h ) at z = h then ∞= pp (8) it is suitable to put these equations in a dimensionless form before applying a numerical scheme to it. the governing equations of natural convection and the boundary conditions can be nondimensionalized by dividing all dependent and independent variables by suitable constant quantities. the following dimensionless variables are used in the present study: ∞ ∞ − − = tt tt w θ , y = y / w and )(* )( 4 2 h w g h wttg g wr w r = − = ∞ υ β ( 9) ))(( rhg wuw u υ = , v = υ wv * and 2222 4*)( υρ rgh wpp p ∞ − = (10) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 56 so, the governing equations (eqs.(1-4)) and the boundary conditions (eqs.(5-8)) becomes in a dimensionless form: 0 yz = ∂ ∂ + ∂ ∂ vu (11) θ+ ∂ ∂ +−= ∂ ∂ + ∂ ∂ )( yz 2 2 y u dz dpu v u u (12) )( 1 yz 2 2 yp vu r ∂ ∂ += ∂ ∂ + ∂ ∂ θθθ (13) ∫= 2/1 0 1 dyu z q a v θ (14) at y = 0.0 0.0 y = ∂ ∂u and v = 0.0 , 0.0 y = ∂ ∂θ (15) at y = 1 / 2 then u = 0.0 v = 0.0 and 1=θ (16) at z = 0.0 then u = u av 0.0=θ and 2 2 a vu p −= 0.0=θ (17) at z = h then p=0.0 (18) the dimensionless average velocity (a vu) and the dimensionless height ( h ) of the duct are given by: )(*)( r a v a v hg wwu u υ = and (19) rhg h h = (20) numerical scheme: explicit space-marching finite difference method is used to solve the set of governing equations. the numerical scheme begins starting from known conditions on the inlet enterance, and marches forward in the z-direction from grid line to another and so on. this method is very effective finite difference technique for laminer and turbulent flow, specially for steady flow. by using this technique a computer code is developed to predict the velocities, pressure and temperature .the continuity , momentum and energy becomes in a finite difference form as follows: al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 57 1. continuity equation ][ 2 1,11,,1,1,, −−−−− −+− ∆ ∆ −=− jijijijijiji uuuuz y vv ( 21 ) 2. momentum equation ji ji ji jijijijiji ji ji ji i ji i jiji u z u z y uuu z y uu u v u p u p uu ,1 ,1 ,1 2 ,11,11,11,11,1 ,1 ,1 ,1 1 ,1 ,1, * 2 *) 2 (* − − − −−−+−−−+− − − − − − − ∆ + ∆ ∆ −+ +∆ ∆ − −+−= θ (22 ) 3. energy equation )] 2 (*) pr 2 [( 1,11,1,12 ,11,11,1 ,1 ,1, y v yu z jiji ji jijiji ji jiji ∆ − − ∆ −+∆ += −−+−− −−−+− − − θθθθθ θθ ( 23 ) 4. average heat transfer rate it is computed from the following balancing : total heat transfer from intet = rate of enthalpy crosses duct section – rate of enthalpy enter the duct, numerically it becomes: yuuu u z q niniiiii ii i av ∆++++= −− *]......0.2 [ 1 1,1,3,3,2,2, 1,1, θθθ θ ( 24 ) since the fluid velocities associated with free convection computation are typically less than 1.0 m/sec gubaidullin ( 2002).the calculations are performed at dimensionless inlet velocity = 0.005 and prandtl number = 0.7.the use of an iterative solution method needs the definition of a convergence and stopping criteria to terminate the iteration process.to make the present solution is stable and to obtain a reasonable accuracy ,so that the solution is not diverage the following relation is used for stability oosthuizen and naylor ( 1999): z∆ < sc 2y∆ ui-1,n-1 ( 25 ) where sc is a constant with the range from ( 0 ) to ( 0.5 ) results and discussion: figure (3) shows a dimensionless temperature variations for a two-dimensional laminer flow in a vertical rectangular duct for prandtl number at 0.7.this figure indicates that the temperature distribution occurs at the region between the line of symmetry and the vertical duct surface. also, the temperature increases gradually as the flow moves upward through the duct , since buoyancy force continuously increasers through the duct. the higher dimensionless al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 58 temperature can be noticed at the surface of the duct, fitting to the boundary condition at this region.this result is in good agreement with sohail (2006) . figures (4) and ( 5 ) shows a dimensionless velocities variation in longitudinal and lateral directions respectively over a two-dimensional vertical rectangular duct for prandtl number at 0.7..the figure refers that the velocity values equals to the average velocity at the inlet section of the duct.by comparsion between the two figures, it shows that in natural convection in a vertical rectangular duct , the lateral velocity component is very much smaller than the longitudinal velocity component. figure (6) shows the dimensionless pressure variation over a two-dimensional laminer flow in a vertical rectangular duct for prandtl number at 0.7. this figure shows that near the inlet of the duct, the viscous forces effect are high and the pressure drops. further up the vertical duct the effects of the density changes due to the temperature changes becomes dominant and the dimensionless pressure values increases. the figure explains that the pressure on the inlet section of the duct is below ambient. this result is in good agreement with mcbain (1999). figure (7) shows the dimensionless heat flux variation over a two-dimensional laminer flow in a vertical rectangular duct for prandtl number at 0.7. this figure shows that the heat flux increases with increasing the height of the duct . this clear increase in the heat flux is due to the increase in the velocity also the other reason of this increasing is due to buoyancy forces which causes an increase in the mass flow rate close to the wall and accelerate the fluid flow so as a result causes an increasing in the amount of the heat flux. conclusions: the following conclusions can be drawn from the results of the present work : 1. for capturing the flow field parameters ; a more mesh points are required near the surface of the vertical rectangular duct. 2. because the flow leaving the duct is parallel to the walls of the duct, the pressure on the exit plane is uniform and equals to the ambient pressure. 3. since the mesh generation has been separated from explicit solver any mesh type can be used. 4. the rise in the value of temperature and the pressure far away from the inlet section of the duct is due to the increasing in the effect of buoyancy forces. 5. the space-marching explicit solution which is used to deal with a two-dimensional vertical rectangular duct proves that it can be used to predict the natural convection flow field parameters accurately and in a short time. 6. from the results obtained, the hydrodynamic properties such as pressure, temperature and velocity are increased when the flow moves upward the duct due to the increasing in the buoyancy force effect. 7. the heat transfer rate is a strong function of velocity. the higher the velocity, the higher the heat transfer rate. 8. no buoyancy force effect occurs in the outer domain of the duct, since the effects of viscosity are negligible. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 59 references: martynenko, o. and khramtsov,p. “free convectiove heat transfer”, springer-verlag, publiciation, germany , 2005. ortega, a. and moffat ,r.," experiments on buoyancy-induced convection heat transfer from an array of cubical elements on a vertical channel wall " ,rept. no. hmt-38, 1986,department of mechanical engineering , stanford university, stanford,ca. pu, l. ,cheng,p and zhao,t."an experimental study of mixed convection heat transfer in a vertical packed channels ", aiaa journal of thermophysics and heat transfer , vo.13 , no.4,1999, pp:: 517-521. cadafalch,j.,oliva,g.,graaf,g.and albets,x." natural convection in a large channel with asymmetric radiative coupled isothermal plates ", journal of heat transfer , ,2002, pp:: 111-130. guimaraes, p. and menon,g."combined free and forced convection in an inclined channel with discrete heat sources ", mecanica computacional , vol.xxiii,2004, pp:: 1-18. mc bain, g. and armfield,s."linear stability of natural convection on an evenly heated vertical wall ", 15 th australasian fluid mechanics conference, university of sydeny , 2004, australia. comunelo, r. and guths,s. " natural convection at isothermal vertical plate: neighbourhood influence ", 18 th international congress of mechanical engineering, ouro preto , mg, 2005. abid, c. ,medale,m.,cerisier,p.and papini,f. " mixed convection in a horizontal rectangular duct heated from below ", international journal of low carbon technologies, vo.1 , no.3,2006, pp:: 236-244. oosthuizen, p. and naylor,d. “introduction to convectiove heat transfer analysis”, mcgraw-hill company, u.s.a. , 1999. gubaidullin, a. “natural convection heat transfer in two fluid stratified pools with internal heat source”, phd thesis, royal institute of technology ,sweden,2002. sohail, a. "natural convection flow in parallel plate vertical channels ", msc. thesis, department of mechanical engineering , king fahd university, dhahran , saudi arabia, 2006. mcbain , g.d. ," fully developed laminer buoyant flow in vertical cavities and ducts of bounded section ", journal of fluid mechanics , vo.401 ,1999, pp:: 365-377. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 60 dimensionless duct height (h) d im en si on le ss d uc t w id th ( w ) figure ( 2 ) vertical rectangular duct which is studied in the present work gravity h l eft w all r ight w all z y w duct inlet duct exit figure(1) mesh generation al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 61 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 dimensionless temperature theta y-axis figure ( 3 ) dimensionless temperature variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0.0045 0.005 0.0055 0.006 0.0065 u u y-axis z-a xis figure ( 4 ) dimensionless velocity variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 62 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 v v y-axis z-axis figure ( 5 ) dimensionless velocity variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005. -1.2e-005 -1.1e-005 -1e-005 -9e-006 -8e-006 -7e-006 -6e-006 -5e-006 -4e-006 -3e-006 -2e-006 -1e-006 pp y-axis z-axis figure ( 6 ) dimensionless pressure variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 63 0 5 e-0 05 0 .0 001 0 .0 001 5 0 .0 002 0 .0 002 5 0 .0 003 0 .0 003 5 0 .0 004 0 .0 004 5 0 .0 005 0 .0 005 5 0 .0 006 0 .0 006 5 0 .0 007 0 .0 007 5 0 .0 008 0 .0 008 5 0 .0 009 0 .0 009 5 y-axis z-axis q q figure ( 7 ) dimensionless heat flux variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٥ دراسة حساب رسوبیات القاع لقنوات ري مختارة وسط العراق إیمان مهدي الموسوي كلیة الهندسة–جامعة بابل :الخالصة تضــمنت الدراســة تقیــیم ثــالث طــرق ریاضــیة لحســاب كمیــة الرســوبیات وتصــاریفها فــي جــزء مــن نهــر الفــرات تـم .نیـة وبیـان مالئمتهـا لقنـوات الـري فـي محافظـة بابـلوفروعه خلف سدة الهندیة ومقارنتهـا مـع التصـاریف المیدا اخذ التصاریف وأشكال المقـاطع العرضـیة والمعلومـات الناتجـة مـن األعمـال الحقلیـة والفحوصـات المختبریـه لنهـر بـــراون مالئمـــة لمعظـــم قنـــوات الـــري -تبـــین أن طریقـــة اینشـــتاین.الدراســـات الســـابقةخـــالل نالفـــرات وفروعـــه مـــ بـراون قـیم اقـرب إلـى القـیم المیدانیـة -طریقة شیلدز حیث أعطت طریقة اینشـتاینكهذا البحث وكذلالمأخوذة في .لیسي فكانت نتائجها بعیدة عن التصاریف المیدانیة-بعكس طریقة انكلز ضفاف األنهار : قنوات الري: التآكل: تنقل الرسوبیا: حمل القاع: الكلمات الدالة study of the expense of bottom sediments of selected irrigation canals in central iraq eman mehdi al-musawi college of engineering – university of babylon abstract sediment amounts and discharges in several of irrigation canals branched from euphrates river downstream al-hindyia barrage. the discharges ,cross section ,field measurements and laboratory tests all are taken from previous works. the results shown that the einstein-brown and shields were more convenious and suitable but einstein-brown methods gave more close value to the field measurements than the other methods ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٦ :الرموز المستخدمة الوحداتالتسمیة الرمز a٢ممساحة مقطع القناة bمعرض قعر القناة dمقطر حبة التربة d50مالقطر المتوسط لحبات التربة dمعمق الماء في القناة d65 مانعم من الوزن% ٦٥قطر الحبة التي تقابل نسبة d35 مانعم من الوزن% ٣٥قطر الحبة التي تقابل نسبة g٢ثا/مالتعجیل األرضي gsالكثافة النسبیة للتربة pمطول المحیط المبلول q ثا/٣مالتصریف المائي المیداني qcaثا/٣مي المحسوبالتصریف المائ gsثا/كغمتصریف الرسوبیات في القناة rh منصف القطر الهیدرولیكي للقناة rh'منصف القطر الهیدرولیكي بالنسبة للحبات rh"منصف القطر الهیدرولیكي من عدم انتظامیة القناة sمانحدار القناة 0م/كغمإجهاد القص المتاخم ٢ cτ٢م/كغمإجهاد القص الحرج u*ثا/مالسرعة القصیة ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٧ u*/ثا/مالسرعة القصیة للحبة u*"ثا/مالسرعة القصیة من عدم انتظام القناة vثا/ممعدل السرعة في القناة wثا/مسرعة الرسوب xمالمسافة الممیزة znانحدار جوانب القناة sρ،sγ) ٣سم/غرامللتربة) ة الوزنیةالكثاف،الكثافة الكتلیة ρ ،γ)٣سم/غرامللماء) الكثافة الوزنیة،الكثافة الكتلیة υ ثا/٢ماللزوجة الكینماتیكیة δمقطر الخشونة الظاهري 35ψشدة القص على الجزیئة الممثلة -:المقدمة فالحبیبـات الصـغیرة ، التـي تنـتج عنهـادئـلحركة الرسوبیات ونقلها في الماء أهمیة كبیرة بسبب األضرار والفوا أمــا الكبیـرة فتترســب فـي قــاع القنـوات فتقــل مسـاحة المقطــع العرضـي للقنــاة ،منهـا تعمـل علــى إدامـة خصــوبة التربـة نتیجـة مـرور المـاء خـالل طبقـات التربـة الضـعیفة فیـدفع تتتولد الرسـوبیاو.وبالتالي تقل التصاریف المارة خاللها كمــا وتنشــأ نتیجــة تعریــة جوانــب وقعــر القنــاة نفســها نتیجــة .تربــة الــى الجــداول الكبیــرة والقنــواتالجریــان حبیبــات ال خاللهــا تــزداد قابلیــة ثانهیــارات التربــة علــى جــانبي القنــاة ومــن زحــف التربــة فــي موســم الفیضــانات واألمطــار حیــ كانشـاء الطـرق العادیـة وطـرق سـكك ومن المصادر األخرى النمو االنشائي على جانبي القناة . القناة على التعریة الحدیــد كمــا وان رمــي الفضــالت مــن المعامــل والمنــاجم ومیــاه الصــرف تشــكل رســوبیات إضــافیة تجــد طریقهــا الــى ).graft, w.h.,( 1971)(القنوات -:خواص الرسوبیات وكیفیة انتقالها تلـــك الرســـوبیات بشـــكل اكبـــر مـــن إن تعامـــل المـــاء مـــع الرســـوبیات ونقلهـــا وترســـیبها یعتمـــد علـــى خـــواص إضـافة إلـى إن عملیـة التـداخل بـین ، )rouse,(1964)(اعتمادها على الخواص الهیدرولیكیة للجریان فـي القنـاة ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٨ ، السائل الحامل والرسـوبیات تتـأثر بخـواص تلـك الرسـوبیات بدرجـة كبیـرة وقیـاس هـذا التـداخل لـیس بـاألمر السـهل -):raudkivi,(1976((ویمكن تقسیم الرسوبیات إلى قسمین a-الرسوبیات المتماسكة)cohesive sediments :( تتكون من جزیئات صغیرة الحجم تترابط فیما بینها .بآصرة التماسك ومقاومتها لعوامل التعریة تعتمد على قوة هذه اآلصرة b -ةالرسوبیات غیر المتماسك)non-cohesive sediments :(ن سابقتها تتكون من جزیئات اكبر م ( بعضها وحركتها في الماء تعتمد على الخواص الفیزیائیة للجزئیة الواحدة كالحجم والشكل والكثافةنومنفصلة ع asawa.,2005.( -:التي تنتقل بواسطة األنهر والقنوات إلى تو تقسم الرسوبیا a الحمل العالق )(suspend load :لقة مع تیار الماءیمثل رسوبیات خفیفة القوام تكون عا. b -حمل القاع(bed load):حمل نتتكون من رسوبیات أثقل من حمل العالق ویشكل الجزء األكبر م -:الرسوبیات الكلي وتسیر بالقرب من القاع وبثالث أنواع من الحركة وهي .االنزالق3. الدحرجة2. القفز1 -:وهو) (graft,( 1971)وهناك تقسیم آخر للرسوبیات a حمل مادة القاع)bed material load ( حیث یحوي حبات الرسوبیات القابلة للترسب في القناة أو النهر ویشكل .هذا النوع الجزء األكبر من حمل الرسوبیات الكلي b-حمل الغسل)wash load (ىوتبقرلحبات الصغیرة الحجم واألنعم الموجودة في تربة القعفانه یحوي ا . عالقة في الماء وال تترسب وتشكل الجزء األصغر من الحمل الكلي للرسوبیات hey et al,(1982) ) :(ومن العوامل المؤثرة على حركة الرسوبیات .خواص التربة5. سرعة السقوط4. الكثافة3. شكل الحبة2-. حجم الحبة1-:األعمال الحقلیة -:-:قنوات الري التي تمت الدراسة علیها١ تمت الدراسة لعدد من قنـوات الـري التـي تأخـذ میاههـا مـن نهـر الفـرات مباشـرة أمـام سـدة الهندیـة مـع عـدد مـن اهها من شط الحلة مباشرة وقد روعي تدرج القنوات والهدف من ذلك هو معرفة موقع النتائج القنوات التي تأخذ می العملیة للرسوبیات من النظریة لهـا لمختلـف القنـوات والتصـاریف وأدنـاه أسـماء ومواقـع القنـوات التـي تمـت دراسـتها -:في البحث م حیــث تــم رصــد التصــریف )٧١(كــم وبعــرض)١٢١(نهــر الفــرات ویبلــغ طولــه ضــمن حــدود محافظــة بابــل )١ بعد سدة الهندیة حیث كان الماء موجها الى القنوات الواقعة أمام سدة الهندیة واخذ التصریف مـرة أخـرى فـي .نفس الموقع في فترة توجیه المیاه إلیه ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٩ م وتأخــذ المیــاه مــن أیســر شــط الحلــة واخــذ التصــریف )٧(كــم وعرضــها )٢٠.٦(ویبلــغ طولهــالقنــاة المحاویــ)٢ .لها خالل فترة التصریف العالي للقناةالمائي م وتأخـذ المیـاه مـن أیسـر )٧٧( كـم وعـرض) ١٠١(قناة شـط الحلـة ویبلـغ طولهـا ضـمن حـدود محافظـة بابـل ) 3 .فترة التصریف العاليلنهر الفرات أمام سدة الهندیة وقد أخذت البیانات من نهر الفرات خال كـــم )٤٩.٥(ة الیســـرى مـــن نهـــر الفـــرات حیـــث یبلـــغ طولهـــا علـــى الجهـــعقنـــاة مشـــروع المســـیب الكبیـــر وتقـــ) 4 م وتأخــذ میاههــا مــن أمــام ســدة الهندیــة وأخــذت البیانــات مــن نهــر الفــرات خــالل فتــرة التصــریف )٢٠.٢(وبعــرض . العالي تتبـع م وهذه قناة ال)١٩(قناة الحسینیة القدیمة وتقع على الجهة الیمنى لنهر الفرات أمام سدة الهندیة وبعرض5) . نظام المناوبة أي أن تصریفها ثابت تقریبا خالل السنة م )١٤.٤(تأخذ المیاه من نهـر الفـرات وتقـع علـى الضـفة الیمنـى أمـام سـدة الهندیـة وبعـرض-:قناة بني حسن) 6 لمـــرتین األولـــى خـــالل فتـــرة كـــم حیـــث أخـــذت البیانـــات مـــن نهـــر الفـــرات)١٢(وتمتـــد داخـــل محافظـــة بابـــل بطـــول )) ١٩٨٣(، فــرج(، ))٢٠٠٠(، مدیریــة ري محافظــة بابــل.( التصــریف العــالي واألخــرى خــالل التصــریف الــواطئ .یوضح نهر الفرات وبعض الفروع قید الدراسة)1(الشكلو -:المواد المستخدمة و المودیل الریاضي یـة للقنـوات كمـا تـم اسـتخدام جهـازین ألخـذ نمـاذج المیـاه التصاریف المائسالتیار لقیادتم استخدام جهاز عدا معتمــد وضــمن دقــة المختبــرات الموجــودة فــي مدیریــة صــیانة وتشــغیل ) األول(،مــن أعمــاق مختلفــة لقیــاس التركیــز لألمــالح والطمــي الموجــود فــي القنــوات ةمشــاریع الــري حیــث یســتخدم ألخــذ نمــاذج المیــاه لقیــاس التراكیــز المختلفــ الحلیـب وتثبـت عراقیة الكبیرة وهو عبارة عـن قفـص حدیـدي توضـع فـي داخلـه قنینـة زجاجیـة مثـل قنینـةواألنهار ال تغلــق القنینــة مــن األعلــى بواســطة ســدادة تتصــل بنــابض حلزونــي وتتصــل ، مــن الجوانــب بواســطة كالبــان حدیدیــة ویبلغ ) كغم20(ل مقداره یعلق في أسفل ثق، بحبل من الجهة األخرى یتحكم به الشخص الذي یقوم بأخذ النماذج یساعد في تثبیت الجهاز في الماء فعندما یـراد اخـذ نمـاذج مـن عمـق معـین تحسـب المسـافة ) سم30(يطوله حوال اعتبــارا مــن الفتحــة العلیــا للقنینــة وتؤشــر المســافات علــى الحبــل الــذي یســتخدم لرفــع الجهــاز وعنــد الوصــول إلــى الثاني الذي یتصـل بالسـدادة التـي تغلـق القنینـة مـن األعلـى وعنـدما العمق المطلوب یثبت هذا الحبل ویشد الحبل .سترفع السدادة ویدخل الماء إلى القنینة یكون النموذج قد اخذ یتكـون الجهـاز . یستخدم للقنوات ذات التصاریف الواطئة واألعماق القلیلـة) جهاز عصا المساحة) (الثاني(أما انج وفي ) 4(انج وقطرها ) 12(عدنیة على شكل اسطوانة ارتفاعها قنینة منمتر وم) 4(من عصا مساحة بطول انــج لخــروج الهــواء بطــرف )1/4(الجـزء األســفل منهــا توجــد فتحــة بقطــر انــج واحــد لــدخول المــاء وفتحــة أخــرى قطــر انج ویتصل الطرف األخر مـن األنبـوب بـأنبوب ) 1/4(وقطر)سم20(بطول ) u(أنبوب معدني على شكل حرف ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٠ انج یمسك الطرف اآلخر منه الشخص الذي یستخدم الجهاز للتحكم بالهواء الداخل والخارج ) 1/4(مطاطي قطر .من القنینة أخذت النماذج من تربة القعـر فـي كـل موقـع تـم فیـه رصـد المقطـع العرضـي للقنـاة وقیـاس التصـریف حیـث المـاء الصـفر علـى جوانـب القنـاة الن ذلـك جاریا بسرعة واضحة وتجنب المنـاطق التـي تتباطـأ فیهـا السـرعة أو تصـل إلـى أما فحص ، یبعدها عن نمط تربة القناةایسبب ترسیب الحمل العالق للماء ویزید من نسبة الطین في تربة القعر مم نمـوذج لغـرض تطبیـق طـرق حسـاب حمـل لالنماذج فقد تم في المختبر لمعرفة الكثافة النسبیة والتحلیل الحجمي لك .))١٩٨٣(فرج،(مادة القاع -:بما یليلفحوصات التربة وتتمثالقیاسات وتتضمن عنـد درجـة حـرارة ) γ(مقسومة على كثافة المـاء ) sγ(تعرف بأنها كثافة الجزیئات الصلبة للتربة -:الكثافة النسبیة-١ ).1(الجدول مئویة كما مبین في )40( موضــوع البحــث ورســمت منحنیــات تاجــري هــذا الفحــص لنمــاذج تربــة القعــر للقنــوا: التحلیــل الحجمــي للنمــاذج-٢ التوزیــع الحجمــي التــي تبــین العالقــة بــین قطــر الحبــة والنســبة المئویــة بــالوزن للحبــات التــي یقــل حجمهــا عــن هــذا .القطر تـم الحصـول علـى قـیم التصـریف المیـداني للرسـوبیات مـن خـالل ضـرب معـدل -:التصریف المیـداني للرسـوبیات-٣ ).1(جدول رقم مبین في التركیز في التصریف المائي وكما -:أهم الطرق الهندسیة والریاضیة لحساب تصریف الرسوبیات :yadav and samtani:(2010)einstein-brown formula)(براون –طریقة اینشتاین -١ :وضعت هذه المعادلة نتیجة لتطویر معادلة اینشتاین وتتمثل في العالقة الریاضیة )1 (  1ƒ= )٢ (3 1 )1( sss s dgf g     )٣ (0 50 0 )( 1        ds )4 ( )1( 36 )1( 36 2 3 2 3 2 1         ssss gdgd f ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥١ ) sg(والذي من خالله یتم استخراج ) 0( و) (یربط بین )2(الشكل وقد وضع جهــاد ) et al.,(2009)turowski(تعتمــد علــى معرفــة إجهــاد القــص الحــرج: shieldsطریقــة شــیلدز –2 ٕ وا -:القص المتاخم وبموجب المعادلة التالیة )5( 5 0 0 )1( )( 1 0 d qsg s c s       . الوزنیـة للمـاءالكثافـة ): s.(أجهـاد القـص الحـرج): cτ. ( إجهاد القـص المتـاخم): 0τ(-:حیث .القطر المتوسط للرسوبیات): d50( و الشـكل مـن ) cτ(إن المعادلة أعاله متجانسة من ناحیة األبعاد لذا یمكن تطبیقها في أي وحـدات وتسـتخرج .)( 3الموضح inglisلیسـي-طریقـة انكلـز-٤ – lacey ( vanoni ,1977 ):أدخلـت قیمـة سـرعة الرسـوب لحبـة حجمهـا -:دل متوسط حجم الحبات وهي بالصیغة أدناهیعا )٦ (g v gd v w vg g s 3 5 0 23/1)( 5 6 2.0   )w: ( تمثل سرعة الرسوب لحبة بحجم)(d50ولكون المعادلة متجانسة یمكن استخدامها بأي وحدات. -:تخدمةالمتطلبات المشتركة للطرق الریاضیة المس) ١ أخـــذت بیانـــات التصـــریف المیـــداني والكثافـــة النســـبیة وانحـــدار القنـــاة والخاصـــة بـــالطرق الریاضـــیة مـــن خـــالل d50 ،d65( أمــا التوزیــع الحجمــي لتربــة القنــاة فقــد تــم الحصــول علــى،)1(جــدول األعمــال الحقلیــة والمختبریــة فــي ،d35 ( والشكلمن خالل منحنیات التوزیع الحجمي )یوضح نموذج لمنحنیـات التوزیـع الحجمـي لتربـة إحـدى )4 مـــن خـــالل ) zn،b( أمـــا بالنســـبة لمقـــاطع القنـــاة فقـــد تـــم الحصـــول علـــى المعلومـــات )) .١٩٨٥(رواء،(القنـــوات )5( والشــكل)2(جــدول وكمــا موضــح فــي )) ٢٠٠٠(، مدیریــة ري محافظــة بابــل( بیانــات وزارة المــوارد المائیــة .رضي عام إلحدى القنواتیوضح نموذج لمقطع ع -:الحسابات الهیدرولیكیة) ٢  نفرض قیمة نصف القطر الهیدرولیكي بالنسبة للحبة)r'h.(  نحسب قیمة السرعة القصیة بالنسبة للحبة من خالل القانون sgru h '' *  ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٢ . انحدار القناة) m2/s) .(s 9,81(تمثل التعجیل األرضي ومقداره ) g(حیث  یحسب سمك الطبقة الطباقیة التحتیة)γ (من القانون ' * 6.1 1 u     تحسب قیمة)x (الذي یمثل عامل التصحیح في السرعة اللوغاریتمیة بموجب العالقة بین)x ( ).d65( یساوي) ks(حیث )6(بالشكل الموضحة ) ks(والنسبة  تحسب قیمة قطر الخشونة الظاهري )δ (بالمتر والني تساوي)x/d65.(  تحسب قیمة معدل السرعة)v (ثا من المعادلة/ بالمتر:   )35.0(2.30 log75.5*'* x uv  35( تحسب قیمة شدة القص على الجریئةψ (قةمن العال:sr d h s ' 3 5 3 5     تحسب قیمة')u''*/v ( الشكل من)( حیث تمثل )7u''* ( عة القصیة بالنسبة إلى عدم انتظامیة السر .القناة  من معرفة النسبة)u''*/v ( تحسب قیمة)u''*.(  تحسب قیمة نصف القطر الهیدرولیكي من عدم انتظامیة القناة)r''h (من المعادلة التالیة : sgru h "" *   تحسب قیمة نصف القطر الهیدرولیكي للقناة من المعادلة: "' hhh rrr   تحسب قیمة السرعة القصیة)u* (من sgru h*  یحسب عمق الماء في القناة)d (من المعادلة: ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٣ 22 12 )(    n n h zdb ddzb r  تحسب مساحة المقطع العرضي للقناة)a (بالمتر المربع من المعادلة:)( dzbda n  یحسب طول المحیط المبتل)ρ (من المعادلة: 22 12  nzdb  تحسب قیمة التصریف المائي)qca (ثا من/ بالمتر المكعب vaqca * .كیة المحسوبة لهذه القنواتإلى النتائج الهیدرولی)٣(جدول رقم ویشیر -:تحلیل النتائج للبیانات تایمثل نتائج الحساب)4(بعد تطبیق الطرق الریاضیة على بیانات لقنوات وتصاریفها المختلفة والجدول .مع قیم تصریف الرسوبیات المیداني لكل منها یالحظ إن كل طریقة أعطت نتائج تصاریف للرسوبیات في القاع تختلف عن الطریقة األخرى ولنفس التصـریف .المائي والظروف الهیدرولیكیة واختلفت كذلك في اقترابها من الحالة المیدانیة طبقـت هــذه الطریقــة علــى مختلــف القنـوات والتصــاریف وقــد اختلفــت نتائجهــا -:بــراون-تحلیـل نتــائج اینشــتین-١ فمثال في نهر الفرات خلف سـدة الهندیـة ولتصـریف مـائي واطـئ ، من قناة ألخرى إال أنها أكثر الطرق مقاربة للواقع ثــا فــي /كغــم ) 25.681(بــراون نثــا كــان تصــریف الرســوبیات للقــاع المحســوب بطریقــة اینشــتی/3م) 151.74(قــدره ثــا ولــنفس الظــروف الهیدرولیكیــة وكمــا مبــین فــي الجــدول /كغــم ) 18.5(حــین كــان التصــریف المیــداني للرســوبیات قنـاة مشـروع المسـیب الكبیـر حیـث كـان يوعموما تتقارب القیم المحسوبة بهذه الطریقة من القـیم المیدانیـة فـ،الالحق أمـــا قنـــاة بنـــي حســـن فـــي حالـــة .ثـــا/كغـــم ) 4.45(المحســـوب ثـــا بینمـــا التصـــریف/كغـــم) 6.6(التصـــریف المیـــداني ثــــــا /كغــــــم)1.2623(ةالتصــــــاریف العالیــــــة والواطئــــــة نالحــــــظ زیــــــادة باتجــــــاه األقــــــرب حیــــــث كانــــــت القــــــیم المحســــــوب بینمــا فــي شــط الحلــة نالحــظ ، ثــا/كغــم)٠.٤(ثــا و/كغــم ) 2.9(ثــا ولتصــریف میــداني للرســوبیات/كغــم)٠.١٧١٧٣(و -ثــا حیــث كانــت بطریقــة اینشــتین/كغــم) 40(عــن القیمــة المیدانیــة لتصــریف الرســوبیاتالعكـس حیــث ابتعــدت القیمــة . ثا/كغم) 17.23(براون ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٤ بــراون -أعطــت نتــائج نوعــا مــا مقاربــة للتصــاریف المیدانیــة بعــد طریقــة اینشــتین-:تحلیـل نتــائج طریقــة شــیلدز2دة عن الواقع حیث التصریف المیداني الرسـوبیات عند التصریف الواطئ یعطي قیمة بعیتفمثال نجد أن نهر الفرا، أمــا فــي قنــاة مشــروع المســیب الكبیــر وقنــاة بنــي حســن فــي ، ثــا/كغــم)72.072(ثــا بینمــا تصــریف شــیلدز/كغــم)18.5( عن القیمـة المیدانیـة فـي حـین تقـارب قنـاة بنـي حسـن فـي ةزیادة هذه القیمة المحسوب.حالة التصریف العالي نالحظ واطئ وبصــورة واضــحة مــع التصــریف المیــداني الرســوبیات وكــذلك فــي قنــاتي المحاویــل والســینیة حالــة التصــریف الــ ثا بعیدة جدا عن القیمة المیدانیـة للرسـوبیات /كغم)116.77(الحلةطفي حین كانت القیمة المحسوبة لقناة ش،القدیمة . ثا/كغم)40(وهي قـة لحسـاب حمـل مـادة القـاع علـى قنـوات مختلفـة ولمختلـف تـم تطبیـق هـذه الطری-:لیسـي-تحلیل نتـائج انكلـز3التصــاریف وقــد لــوحظ اخــتالف فــي النتــائج مــن قنــاة ألخــرى مــن حیــث اقترابهــا مــن التصــاریف المیدانیــة للرســوبیات ثا بینما كان /كغم) 1.2(حیث نجد قیمة واحدة مقاربة عند قناة الحسینیة القدیمة وبقیمة تصریف میداني للرسوبیات أمـــا بالنســـبة للقنـــوات األخـــرى نجـــد ارتفـــاع لقـــیم تصـــاریف ،ثـــا/كغـــم)1.28(ف الرســـوبیات بطریقـــة انكلـــز لیســـيتصـــری الرسوبیات وبشكل ملحوظ جدا ماعدا في قناة السینیة القدیمة نالحظ نقصان فـي قیمـة تصـریف الرسـوبیات وعمومـا .في هذه الطریقة تم الحصول على قیمة واحدة مقاربة للواقع من خالل معرفة تصاریف الرسوبیات المیدانیة والمحسوبة وبمعادالت ریاضیة حیث ) r(حساب قیم تم براون قیم تشیر من خاللها بأنها األقرب إلى القیم المیدانیة ومن ثم تم إیجاد معادلة جدیدة -أعطت طریقة اینشتین .یمثل النتائج المحسوبة)٦(و)٥(والجدول تمثل جمیع قنوات الدراسة -:االستنتاجات من خالل القیاسات المیدانیة للرسوبیات تمیزت حبات تربة القعر بخشونتها في القنـوات الكبیـرة وتـنخفض وقـد لـوحظ إن حبـات ، كما إن حبات التربة كانت اخشـن فـي مقدمـة القنـاة منهـا فـي الـذنائب، في القنوات الصغیرة ونتها وغیــر متجانســة عنــد انخفــاض هــذه الخشــونة كمــا تــم تقریــب المقطــع التربــة تكــون متجانســة كلمــا ازدادت خشــ سابقا حیث تـم ةالعرضي المیداني الى مقطع شبه منحرف وبموجب المعلومات المتوفرة استخدمت الطرق المذكور یف االعتماد على القیاسات المیدانیة المرصودة والتي تتمثل في رصد المقطع العرضي للقناة وكذلك قیاس التصـر بعـدها تـم اخـذ النمـاذج وتحلیلهـا مختبریـا كـإجراء .المیداني للرسوبیات وقد استخدمت عدة أجهـزة لقیـاس الرسـوبیات وقد جاءت نتائج حسابات .وكانت ضمن دقة المختبرات الموجودة)) ١٩٨٣(فرج،(فحص التحلیل الحجمي والكثافة عنـد مقارنـة نتـائج أي مـن هـذه الطـرق مـع حمـل حمل مادة القاع متباینـة باسـتخدام تلـك الطـرق كمـا حصـل تبـاین الرسوبیات المیداني وقد كان من أسباب هذا التباین هو بعـض التحدیـدات والفرضـیات التـي اسـتخدمت مـن خـالل -:في اإلمكان ذكر االستنتاجات التالیة ،تطبیق هذه الطرق ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٥ دلـنفس الظـروف الهیدرولیكیـة قـأعطى تطبیق الطرق الریاضیة نتائج متباینة فـي حسـاب حمـل مـادة القـاع)١ .تیصل هذا االختالف الى نسبة عالیة جدا من الفر وقا إن كمیـــة الرســــوبیات التــــي تجــــري فــــي قنــــوات الــــري قـــد تكــــون اكبــــر أو اصــــغر مــــن تصــــریف الرســــوبیات ) ٢ .المحسوب في أي من الطرق المستخدمة في هذا البحث براون في بعض القنوات الكبیرة لكنها تكون قریبة جـدا فـي القنـوات -نتزداد معقولیة استخدام طریقة اینشتای) ٣ . المتوسطة حیث كانت قیمتها ضمن الحدود المعقولة بالنسبة لغیرها من الطرق -:التوصیات -:یمكن توجیه التوصیات التالیة مادة القـاع بـاختالف قـیم التصـریف الختالف كفاءة النتائج التي تعطیها أي من الطرق الریاضیة لحساب ) ١ یمكن استخدام أكثر من طریقة للقنـاة التـي یسـیر فیهـا المـاء بتصـاریف مختلفـة للخـروج بـالطرق الریاضـیة ، المائي . المالئمة إجراء الدراسات والبحوث على قنوات عدیدة متشابهة مـن حیـث الحجـم ومعـدل السـرعة وكمیـة لرسـوبیات ) ٢ ریقـــة ریاضـــیة معینـــة للقنـــاة التـــي یجـــري فیهـــا المـــاء بظـــروف هیدرولیكیـــة معینـــة تحـــددها هـــذه المنقولـــة لتثبیـــت ط .الخواص المصادر جمهوریة العراقوزارة الري " الري في محافظة بابل ) : " ٢٠٠٠(، مدیریة ري محافظة بابل . رسالة مقدمة إلى "ونظام توازنها خواص بعض جداول الري العراقیة) " ١٩٨٣(فرات احمد ،، فرج ، . جامعة بغداد كجزء من متطلبات نیل درجة الماجستیر في موضوع الهایدرولیك ، رسالة "حركة الرسوبیات في قسم من قنوات الري في وسط العراق ) " ١٩٨٥(رواء إسماعیل محمد ، كجزء من متطلبات نیل درجة الماجستیر في مقدمة إلى قسم البناء واإلنشاءات في الجامعة التكنولوجیة . هندسة البناء واإلنشاءات  asawa, g. l.,(2005) " irrigation and water resources engineering " book from indian institute of technology roorkee ,india .  graft, w.h.,( 1971), "hydraulics of sediment transport", mcgraw –hill book company, first edition. ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٦  hey, r.d., bathurst , j.c and thorne, c,r., (1982)" gravel bed river ",john wiley and sons ,first edition.  raudkivi, a.j.,(1976), "loose boundary hydraulics", program press, 2nd edition, auckland.  rouse,( 1964)," engineering hydraulics" john wiley and sons.  shields, a., (1936), "application of similarity principles and turbulence research to bedload movement mitteilunger der preussischen versuchsanstalt for wasserbau and schiffbau, 26, pp. 5-24.  turowski, jens, m., yager, elowyn, m., badoux alexandre, rickenmann dieter and molnar, p., (2009) "the impact of exceptional events on erosion, bed load transport and channel stability in a step-pool channel" earth surface process and landforms 34, 16611673.  vanoni , vito a., editor,(1977), "sedimentation engineering" asce –manuals and reports on engineering practice –no. 54, reprinted .  yadav ,s. m., and samtani ,b.k.,(2010), " evaluation and improvement of bed load formula using tapi river data, india " journal of water resource and protection ,vol.2 ,pp.(245-250). .الكثافة النسبیة وانحدار القناة،یوضح التصریف المائي المیداني ) 1(جدول اسم القناة أو النهر ةالكثافة النسبیالموقع )sγ( التصریف المائي )ثا /م(المیداني انحدار القناة )s( 2.66151.740.0001خلف سدة الهندیةنهر الفرات 2.66540.730.0001الهندیةخلف سدةنهر الفرات 2.710.70.000075شط الحلةقناة المحاویل 2.692500.000075نهر الفراتقناة شط الحلة 2.7700.000081نهر الفراتمشروع المسیب الكبیر 2.727.930.00008نهر الفرات قناة الحسینیة القدیمة 2.684.440.000075نهر الفراتقناة بني حسن 2.6826.90.000075نهر الفراتقناة بني حسن .نتائج حساب متطلبات الطرق الریاضیة) :2(جدول ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٧ اسم القناة أو النهر الموقع الكثافة النسبیة )sγ( ضعر القناة )b (متر انحدار األكتاف zn %65القطر )متر(انعم بالوزن d65 %35القطر )متر(انعم بالوزن d35 %50قطر ال )متر(انعم بالوزن d50 2.6671.07.00.000150.0001330.000015سدة الهندیةخلفنهر الفرات 2.6672.09.00.000150.0001330.000015سدة الهندیةخلفنهر الفرات 2.77.01.50.00010.000040.000008شط الحلةقناة المحاویل 2.6977.01.50.000120.0000960.0000105نهر الفراتقناة شط الحلة المسیب قناة مشروع الكبیر 2.720.21.00.000120.00010.00011نهر الفرات 2.7219.01.60.000110.0000960.00001نهر الفراتالقدیمةقناة الحسینیة 2.6814.42.00.000110.0000760.000098نهر الفراتقناة بني حسن 2.6814.41.750.00010.0000760.000098نهر الفراتحسنقناة بني النتائج الهیدرولیكیة المحسوبة) ٣(جدول ھ ن ل ا و أ ة ا ن ق ل ا م س قرا و م ل ة عا ی ب س ن ل ا ة ف ا ث ك ل )sγ( ا ا م ل ا ق م ءع md ط ق ل ا ف ص رن الھیدرولیكي )rh( m ينصف القطر الھیدرولیك )r'h( m ا ن ق ل ا ر ا د ح ن ةا )s( ع ر س ل ا ل د ع ةم (v) m/s ي ر ص ت ل فا q(m3/s(المیداني ا ر ف ل ا ر ھ 2خلف سدة الھندیةتن . 6 63 . 3 8 82 . 6 9 8 30 . 3 1 10 . 0 0 0 10 . 4 7 3 21 5 1 . 7 4 ا ر ف ل ا ر ھ 2خلف سدة الھندیةتن . 6 64 . 3 0 4 53 . 1 7 8 71 . 5 0 30 . 0 0 0 11 . 1 3 45 4 0 . 7 3 2ةشط الحللالمحا ويقناة . 71 . 4 8 5 51 . 1 0 9 50 . 4 80 . 0 0 0 0 7 50 . 4 9 6 3١ ٠ . ٧ اقناة شط الحلة ر ف ل ا ر ھ 2تن . 6 93 . 2 0 92 . 9 6 41 . 2 4 50 . 0 0 0 0 7 50 . 8 7 4 5٢ ٥ ٠ ارقناة مشروع المسیب الكبي ر ف ل ا ر ھ 2تن . 73 . 4 9 52 . 7 4 80 . 4 3 50 . 0 0 0 0 8 10 . 57 0 م ی د ق ل ا ة ی ن ی س ح ل ا ة ا ن اةق ر ف ل ا ر ھ 2تن . 7 21 . 6 6 21 . 4 2 60 . 1 3 50 . 0 0 0 0 80 . 2 2 0 47 . 9 3 اني حسقناة بن ر ف ل ا ر ھ 2تن . 6 81 . 3 21 . 1 0 6 60 . 1 2 7 10 . 0 0 0 0 7 50 . 1 9 6 54 . 4 3 ن س ح ي ن ب ة ا ن اق ر ف ل ا ر ھ 2تن . 6 82 . 4 8 0 52 . 8 4 0 50 . 4 5 70 . 0 0 0 0 7 50 . 4 8 1 52 6 . 8 9 9 .النتائج المحسوبة في الطرق الریاضیة النظریة): ٤(جدول ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٨ النهروالقناة أاسم التصریف المائي المیداني (q )m3/s سرعة الجریان v) m/s( العمق m)d( القطر المتوسط d50*10-4 m )gs(…. )kg/s(تصریف الرسوبیات المیداني -ناینشتی براون شیلدز -انكلز لیسي 151.74103.3881.518.525.68172.072136.387نهر الفرات 540.73104.30451.5162.342.588263.346140.45نهر الفرات 10.77.51.48550.82.10.21351.27451.9242قناة المحاویل 2507.53.2091.054017.23116.774526.83قناة شط الحلة قناة مشروع المسیب الكبیر 708.13.4951.16.64.4519.45363.525 ٧.٩٣٨1.662١.٠١.٢٠.٥٦٦٤٢.٠١٧٦١.٢٨قناة الحسینیة القدیمة 4.447.51.320.980.40.171730.76325.8قناة بني حسن 26.97.52.48050.982.91.26238.393741.03قناة بني حسن ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٩ .لجمیع قنوات الدراسة) r(تصریف الرسوبیات المیدانیة والمحسوبة وقیمة ) ٥(جدول والقناة أاسم النهر تصریف الرسوبیات المیداني gs)( kg/s لیسي-انكلزشیلدزبراون-ناینشتی -ناینشتی kg/sبراون r شیلدز )kg/s( r لیسي-انكلز )kg/s( r 637.2-28.95136.387-38.8172.072-18.525.681تنهر الفرا 3683.39-162.342.58873.79263.3462.256140.45نهر الفرات 2372.5-2.10.213589.831.27439.3351.9242قناة المحاویل 11217-4017.2356.92116.77١٩١.٩٢4526.83قناة شط الحلة مشروع المسیب قناة الكبیر 6.64.45٣٢.٥٧19.453١٩٤.٧٤63.525-862.5 قناة الحسینیة القدیمة ١.٢٠.٥٦٦٤52.8٢.٠١٧٦68.1١.٢٨-6.66 0.40.17173٥٧.٠٦0.763290.85.81350قناة بني حسن 1314.8-2.91.2623٥٦.٤٧8.3937١٨٩.٤٣41.03قناة بني حسن .ریف المیداني والمحسوب المعادلة مع النتائج بین التص): ٦(جدول المعادلة بین التصریف المیداني والمحسوب y = a*x^6+b*x^5+c*x^4+d*x^3+e*x^2+f*x+g valuevariabler^2stderror 2.6e-005a 0.9991.228 -0.002b 0.071c -0.809d 2.976e -1.389f 1.341g ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٠ مواقع الجداول موضوعة البحث ): 1(الشكل function ф =f (1/ψ) for einstein –brown (vanoni , 1977) ):٢(الشكل 3 1 )1( sss s dgf g     ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦١ جهاد القص الالب):٣(الشكل ٕ ،١٩٣٦( ، عديالعالقة بین رقم رینولدز للقص وا ( shields مقطع عرضي ومنتظم إلحدى القنوات):٥(الشكل ــم عـــــــ ألن ة ا ربـــــــــ للت ــــــة ویـــ لمئ ة ا ــــــــب نس ال زن الو ب القناةمنحني التوزیع الحجمي لتربة): 4(الشكل ).d65( والنسبة xةالعالقة بین عامل تصحیح السرعة اللوغاریتمی): ٦(الشكل ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٢ على نموذج الجریئة٣٥ψالعالقة بین شدة القص ): ٧(الشكل )).١٩٨٥(،رواء. (u''*/vوالنسبة matlab modeling and simulation for fourth order modal response control system enhancement by pid controller tuning genetically al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٣٦ genetic algorithms based optimization design of tunning a pid controller reath .j. tulafeh mechanical engineering -technical collage / almusiab abstract: the main aim of this paper is to tune a pid controller to enhance the out put response of fifth order modal with sensor in feedback control system . this controller tuned by genetic algorithms, because the fifth order system is notoriously difficult to control optimally using conventional pid controller. genetic algorithms (ga) are effective at finding high performance areas in large domains and the ideal choice to tune the pid controller can be achieved. genetic algorithms were examined in detail, it was decided to create an objective function which evaluates the optimum pid gains based on the controlled systems overall error. ga’s outperformed standard tuning practices, e.g. ziegler nichols, at designing of pid controllers, in the tests carried out. experimentally, it can be determined that the integral square error (ise) performance criterion produces the most effective pid controllers compared with other performance criterion. key words: pid controller , intelligent control technique, genetic algorithms, avr, fifth order plant اتالب وتحسین ادائها باستخدام تمثیل أنظمة السیطرة ذات الدرجة الخماسیة باستخدام برنامج الم المسیطر الثالثي المنغم بالخوارزمیات الجینیة ریاض جاسم طلیفح. م.م قسم هندسة تقنیات المضخاتالمسیبالكلیة التقنیة-هندسة میكانیكیة :الخالصة نظمـه مـن الدرحـة الخماسـیة منغم بطـرق ذكیـة لتحسـین اداء ا)pid(البحث هو انشاء مسیطر ثالثي الهدف الرئیسي في هذا حیث ان یصعب . gaهذا المسیطر تم تنغیمه باستخدام الخوارزمیات الجینیة ، تحوي على متحسس في االشارة الراجعه من االخراج ) ziegler nichols(السیطره على هكذا نوع من االنظمة علیها باسـتخدام المسـیطر الثالثـي المـنغم بـالطرق التقلیدیـة مثـل طریقـة الیجـــاد )ise(الخوارزمیـــات الجینیـــة ذات تـــاثیر كبیـــر فـــي ایجـــاد المتغیـــرات للمســـیطر الثالثـــي وقـــد اختبـــرت الطریقـــة واســـتخدم عامـــل تــم الحصــول علــى نتــائج جیــده ذات معامــل خــط قلیــل أي اســتجابه جیــده وقورنــت النتــائج مــع الطــرق الســابقة للتنغــیم .االسـتجابة الجیــده . لطریقه الذكیه بالتنغیم جیده جدا واوضحت بان هذه ا al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٣٧ introduction: pid controller is a one of the earliest industrial controllers. it has many advantages: its cost is economic, simple easy to be tuned and robust. this controller has been proven to be remarkably effective in regulating a wide range of processes [astrom and hagglund 1988 ]. more than 90% of industrial controllers are still implemented based around pid algorithms, particularly at lowest levels. with its three-term functionality covering treatment to both transient and steady-state responses, proportionalintegral-derivative (pid) control offers the simplest and yet most efficient solution to many real-world control problems. pid controller is a convenient fractional order structure that has been employed for control purposes [ang 2005]. an fopid is characterized by 3 parameters: the proportional gain, the integrating gain, the derivative gain, the integrating order and the derivative order. there are a number of efficient search algorithms that have their origins in the field of biological evolutionary and are known as evolutionary computation , the field of evolutionary computation is comprised mainly of genetic algorithms ,genetic programming and evolutionary strategies [ang 2005] pid controller and optimization algorithms pid controller over 90% of the controllers in operation are pid controllers. despite the development of more advanced control strategies, the majority of industrial control systems still use pid controllers because they are standard industrial components. figure (1) shows the control system with pid controller. the three parameters that must be determined (some times, must be optimized) for the given process[kuo and golnaraghi2003 ], to give the desirable output responses for the plant are: proportional gain, integral gain and derivative gain. the transfer function of the pid controller looks like the following: c(s) = kp + ki / s + kd s = (kd s2 + kp s + ki) /s ……(1) p = proportional gain i = integral gain d = derivative gain the error signal (e) will be sent to the pid controller, and the controller computes both the derivative and the integral of this error signal. the signal (u) just past the controller is given as: u= kp.e + ki ∫e.dt + kd de/dt ......... (2) this signal will be sent to the plant, and the new output (y) will be obtained. this new output (y) will be sent back to the sensor again to find the new error signal (e). the controller takes this new error signal and computes its derivative and its integral again. this process goes on and on [jack2004]. table (1), illustrates effect of pid controllers parameters on transient response. these correlations may not be exactly accurate, because kp, ki, and kd are dependent of each other. in fact, changing one of these variables can change the effect of the other two. for this reason, the table should be used as a reference when determining the values for ki, kp and kd. the steady state response can be improved by the addition of an integral term, and the speed of response can be increased by the addition of a derivative term. a common pid control transfer function in equation (2-1) can be re-written as: 0 t al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٣٨ ......... (3) where the controller gains ki and kd are given by: ........ (4) ......... (5) pid controller tuning many methods to determine the pid parameters have been developed during the last four decades. all these methods tried to optimize some performance criteria that mostly constitute a nonlinear optimization problem, in which many local minimums may be present [becerra 2003 ]. the most popular applications of the pid controllers in power system control are in the control circuits of power generation plants (synchronous generator), either in load frequency control (lfc) as a power system stabilizer to control the load angle variation and stability of the power system, or as an auxiliary regulating controller inserting in the excitation control system together with the automatic voltage regulator to control and enhance the terminal voltage transient stability response [jones and moura 1995 ]. all the previous or conventional tuning methods for the pid parameters (gains) are time consuming and some times manually done. even if real time expert systems are used to automate the tuning process, also these methods utilize only a few available information's about the dynamic behavior of the system since the power system is a dynamic system, so they often yield no proper tuning [jones and moura 1995 ]. one of the must popular conventional tuning methods for the pid controller is the modified ziegler nichols [ziegler and nichols1942]. this method is very simple and practical. the system is placed under proportional control and taken to the limit of stability by increasing the gain until permanent oscillations are achieved. the gain at which this occurs is called the ultimate gain (ku), and the period of this oscillation is known as the ultimate period (tu). with these two parameters, the controller parameters kp, ti and td can be calculated as shown in table (2). the other popular conventional tuning methods for pid controller are the classical tuning method which depends on the trial and error,. the main part of the objectives of this research is to design and tune a powerful controller that based on the genetic algorithm optimization technique. in other words, to optimize the parameters of the pid controller using genetic algorithm instead of conventional tuning method that mentioned above. the pid parameters are obtained by minimizing one of the most popular error criteria which is the ise criteria, where the minimization is performed using genetic algorithm (ga) [ziegler and nichols1942]. the design of adaptive controllers to improve the performance of the power system has been a topic of research for a long time in the electrical power system field, because, the parameters in this system are changing with time, slowly due to environmental effects or rapidly due to faults. thus it is necessary to update the controller parameters with system changes, so the need for the intelligent adaptive controller being very essential. the world directed toward using the intelligent optimization tuning methods. one of the best robust method and have been enjoying increasing popularity in the al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٣٩ field of numerical optimization in recent year is the genetic algorithm which will be discussed in details in the next section. error criteria in pid controller: in order to select the best controller, we define a cost function. the cost function mainly derives on how the controller reacts to a given disturbance. there are many types of cost functions (optimization criteria) and some times it called performance indexes. in fact, we can define infinitive criterions. the most popular are [kuo and golnaraghi2003]: integral of absolute value of error iae =   0 e(t) dt ……( 6) integral of error squared ise =   0 e(t)2dt ……..(7) integral time weighted error itae =   0 t e(t) dt ……....(8) for the above functions we simulate the results so as to optimize the controller. pi (d) control is perhaps the most basic form of feedback. it is very effective and can be applied to a wide range of problems. this type of control has become one of the most important ways, for the scientific and the industrial control users to work together especially in power system control, in prescience words, in synchronous machine excitation control system [goodwin etal.2000]. genetic algorithms genetic algorithms (ga’s) are a stochastic global search method that mimics the process of natural evolution. the genetic algorithm starts with no knowledge of the correct solution and depends entirely on responses from its environment and evolution operators (i.e. reproduction, crossover and mutation) to arrive at the best solution. by starting at several independent points and searching in parallel, the algorithm avoids local minima and converging to sub optimal. a genetic algorithm is typically initialized with a random population consisting of between 20-100 individuals. this population (mating pool) is usually represented by a real-valued number or a binary string called a chromosome. for illustrative purposes, the rest of this section represents each chromosome as a binary string. how well an individual performs a task is measured is assessed by the objective function. the objective function assigns each individual a corresponding number called its fitness. the fitness of each chromosome is assessed and a survival of the fittest strategy is applied. [. holland1992 ]. in this project, the magnitude of the error will be used to assess the fitness of each chromosome. there are three main stages of a genetic algorithm, these are known as reproduction, crossover and mutation. reproduction during the reproduction phase the fitness value of each chromosome is assessed. this value is used in the selection process to provide bias towards fitter individuals. just like in natural evolution, a fit chromosome has a higher probability of being selected for reproduction. an example of a common selection technique is the ‘rwl’ selection method, each individual in the population is allocated a section of a roulette wheel; the size of the section is proportional to the fitness of the individual as al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٠ shown in figure 2. a pointer is spun and the individual to whom it points is selected. this continues until the selection criterion has been met. the probability of an individual being selected is thus related to its fitness, ensuring that fitter individuals are more likely to leave offspring. multiple copies of the same string may be selected for reproduction and the fitter strings should begin to dominate [passino and yorkovich 1998]. there are a number of other selection methods available and it is up to the user to select the appropriate one for each process. all selection methods are based on the same principal i.e. giving fitter chromosomes a larger probability of selection solutions [holland1992]. four common methods for selection are: 1. roulette wheel selection 2. stochastic universal sampling 3. normalised geometric selection 4. tournament selection crossover once the selection process is complete, the crossover algorithm is initiated. the crossover operations swaps certain parts of the two selected strings in a bid to capture the good parts of old chromosomes and create better new ones. genetic operators manipulate the characters of a chromosome directly, using the assumption that certain individual’s gene codes, on average, produce fitter individuals. the crossover probability indicates how often crossover is performed. a probability of 0% means that the ‘offspring’ will be exact replicas of their ‘parents’ and a probability of 100% means that each generation will be composed of entirely new offspring. the simplest crossover technique is the single point crossover. there are two stages involved in single point crossover [holland1992].: 1. members of the newly reproduced strings in the mating pool are ‘mated’ (paired) at random. 2. each pair of strings undergoes a crossover as follows: an integer k is randomly selected between one and the length of the string less one, [1,l-1]. swapping all the characters between positions k+1 and l inclusively creates two new strings. more complex crossover techniques exist in the form of multi-point and uniform crossover algorithms. multi-point crossover is an extension of the single point crossover algorithm and operates on the principle that the parts of a chromosome that contribute most to its fitness might not be adjacent. there are three main stages involved in a multi-point crossover. 1. members of the newly reproduced strings in the mating pool are ‘mated’ (paired) at random. 2. multiple positions are selected randomly with no duplicates and sorted into ascending order. 3. the bits between successive crossover points are exchanged to produce new offspring. in uniform crossover, a random mask of ones and zeros of the same length as the parent strings is used in a procedure as follows. mutation using selection and crossover on their own will generate a large amount of different strings. however there are two main problems: 1. depending on the initial population chosen, there may not be enough diversity in the initial strings to ensure the ga searches the entire problem space. 2. the ga may converge on sub-optimum strings due to a bad choice of initial population. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤١ these problems may be overcome by the introduction of a mutation operator into the ga. mutation is the occasional random alteration of a value of a string position. it is considered a background operator in the genetic algorithm the probability of mutation is normally low because a high mutation rate would destroy fit strings and degenerate the genetic algorithm into a random search. mutation probability values of around 0.1% or 0.01% are common, these values represent the probability that a certain string will be selected for mutation i.e. for a probability of 0.1%; one string in one thousand will be selected for mutation. once a string is selected for mutation, a randomly chosen element of the string is changed or ‘mutated’[holland1992]. the steps involved in creating and implementing a genetic algorithm are as follows 1. generate an initial, random population of individuals for a fixed size. 2. evaluate their fitness. 3. select the fittest members of the population. 4. reproduce using a probabilistic method (e.g., roulette wheel). 5. implement crossover operation on the reproduced chromosomes (choosing probabilistically both the crossover site and the ‘mates’). 6. execute mutation operation with low probability. 7. repeat step 2 until a predefined convergence criterion is met. the convergence criterion of a genetic algorithm is a user-specified condition e.g. the maximum number of generations or when the string fitness value exceeds a certain threshold.[ holland1992].: . elitism with crossover and mutation taking place, there is a high risk that the optimum solution could be lost as there is no guarantee that these operators willpreserve the fittest string. to counteract this, elitist models are often used. in an elitist model, the best individual from a population is saved before any of these operations take place. after the new population is formed and evaluated, it is examined to see if this best structure has been preserved. if not, the saved copy is reinserted back into the population. the ga then continues on as normal genetic algorithms versus traditional methods genetic algorithms are substantially different to the more traditional search and optimization techniques. the five main differences are [holland1992].: 1. genetic algorithms search a population of points in parallel, not from a single point. 2. genetic algorithms do not require derivative information or other auxiliary knowledge; only the objective function and corresponding fitness levels influence the direction of the search. 3. genetic algorithms use probabilistic transition rules, not deterministic rules. 4. genetic algorithms work on an encoding of a parameter set not the parameter set itself (except where real-valued individuals are used). 5. genetic algorithms may provide a number of potential solutions to a given problem and the choice of the final is left up to the user. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٢ simulation result for tuning pid controller in this paper a system was chosen and a pid controller was designed for it using conventional methods and modern method to evaluate the output response of the system and the results of the two techniques were compared. the system chosen was: the fifth order plant with sensor and pid controller is shown in figure( 4 ) conventional methods (ziegler-nichols designed pid controller) in this section the obtained simulation model for the fifth order plant will be examined by using a conventional pid controller tuned through using a ziegler – nichols method , which is classical tuning method as explained below. the optimized pid controllers parameters values using conventional tuning method are also represented. all figures with a simulation time of 1 second coincide with the x – axis, while the terminal response in each figure in y – axis .the ziegler-nichols (z-n) methods rely on open-loop step response or closed-loop frequency response tests [j. g. ziegler and n. b. nichols, optimum setting for automatic controllers, 1942.]. a p, pi or pid controller is tuned according to a table (3) based on the process response. the pid tuning is calculated from the z-n tuning table found in literature such as åström and hägglund (1995). table (3) shows the tuning rules for a pid controller. p and pi controllers have separate tuning rules. for a discrete-time pid controller the table should be revised to take the sampling time into account. there is, however, no discrete z-n tuning table, so table (3) is used in lack of other. a discrete-time controller approximates a continuous-time controller at small sampling times, so this tuning rule is only used for the shortest sampling times. the z-n method is designed for rejecting load disturbances. for reference step changes it performs worse and gives for simple systems a damped oscillating response. the tuning is usually bad for higher order systems and can only be considered as a simple first aid tuning. for comparison without controller response is shown in figure (5) also the error signal is shown in figure (6). when the pid controller tuned by conventional method used the response is enhanced and the good time parameter is obtained as shown in figure( 7) and figure (8) intelligent method (genetic pid controller) genetic algorithm will be applied to the area of pid optimization in both an off-line and on-line tuning environment. tuning a system off-line means that the pid parameters of the controller are updated when the system has been taken off-line. the pid values are updated using the systems input and output data after the system has been placed. these updated pid values are used in place of the old pid values and the system is brought back online. this process continues until the optimum pid coefficients of the system have been obtained. tuning a system on-line means that the pid parameters of a controller are updated while the system is on-line. the systems input and output data are collected at regular intervals and used to update the pid values. the new pid values are then used in place of the old ones until a newer updated set of pid values have been deduced at the next time interval. the optimizations of the controller’s pid parameters using genetic algorithms will be compared to that of a standard method for designing pid controllers (ziegler-nicholas tuning method). the genetic algorithms are used here to find the optimum pid values for the 5th order system model. the important steps of ga-pid controller are explained below: the parameters types for the used genetic algorithms are ([holland1992]):  type of selection = roulette wheel selection. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٣ the selection is a method for increasing the number of solution candidates having high fitness values. there are several types of selection such as (roulette wheel selection (rws), and rank selection).  type of crossover = single point crossover. the ga is not only filling the population with the best of the first generation by choosing better solutions, but there are also created new solutions from the original database which can be done by crossover operator. there are several types of crossover operator, some of these are (single, two, multi point crossover and arithmetic crossover).  type of mutation = uniform mutation mutation operator is another degree of freedom in search procedure, which is frequently used in design of ga. the need for mutation is to keep diversity in the population. there are many ways of accomplishing mutation such as binary, uniform, non-uniform and boundary mutation (k. m. passino and s. yorkovich, fuzzy control, 1998.].  fitness function =1/(ise+0.00001) the fitness (objective function) is chosen depending on the problem in hand such that the individuals having high fitness values are the good solution candidates for the optimization. therefore, selection of the next generation will dependent on the fitness measure . the optimization criterion which is applied in the present work is integral of square error (ise).  probability of crossover = 0.95  probability of mutation = 0.01  max. no. of generation = 500  population size = 200 figure (9) show the output response when gpid controller. figure (10) shows the error response is -transfer function for pid controller: 0.01312 s^2 + 0.23015 s + .29113 t.f = ------------------------------------------------( 9 ) s optimized genetic for pid : kp = 0.13, ki = 1.02, kd = 0.001 -transfer function of fifth order model with sensor modal as shown in figure (4 ) and genetic pid controller is(k. m. passino and s. yorkovich,1998)s transfer function = 3.995e-009 s7 + 6.553e-006 s6 + 0.001944 s5 + 0.185 s4 + 4.357 s3 + 30.34 s2 + 54.81 s + 29.11 -----------------------------------------------------------------------------------(10) 1.152e-008 s7 + 1.429e-005 s6 + 0.002247 s5 + 0.1146 s4 + 4.013 s3 + 31.89 s2 + 54.35 s + 29.11 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٤ conclusions from the simulation result ,the conventional pid tuning methods are time consuming and some times depends on the human experts, but the gas are the best choices and used here as optimizing techniques for pid parameters optimization and the obtained results of the ises are comparable. -the genetic algorithm is really powerful search optimization algorithm, and when number of generation is increase the best result is obtain but the computation time for the execution program is increased also. -the overall enhancements results of the performance indexes or the optimization criteria (ises), which being a measures for the terminals transient voltage stability enhancements through all the works references: k. j. astrom and j. hagglund, “automatic tuning of pid controllers”, instrument society of america, 1988 k. h. ang, g. chong, and y. li, "pid control system analysis, design, and technology" ieee transactions on control systems technology , vol. 13, no. 4, july, 2005. b.c. kuo and f. golnaraghi, automatic control systems, john willy &sons, inc, 8th edition, usa, 2003. [4] h. jack, dynamic system modeling and control, hugh jack press, usa, 2004. v. m. becerra, process control simulating using simulink, sept. 2000, updated for matlab 6.5 – june 2003. a.h. jones and p. b. de moura oliveira, "genetic auto-tuning of pid controller", genetic algorithms in engineering systems: innovations and applications, 12-14 september 1995, conference publication no. 414, iee, pp. 141-145, 1995. j. g. ziegler and n. b. nichols, "optimum setting for automatic controllers", trans. asme, vol. 65, pp.433-444, 1942. g. c. goodwin, s. f. graebe and m. e. salgado, control system design, santa maria press, valparaiso, chile, 2000. j. holland, adaptation in natural and artificial systems, 2nd edition, mit press / bradford book edition, cambridge, massachusetts, 1992. k. m. passino and s. yorkovich, "fuzzy control", addison – wesley longman, inc., 1998. a.a. albakry " optimize parameters controller of synchronous machine to enhance transient t response " , department of electrical engineering, university of technology iraq, thesis, pp. 90-95,2007 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٥ table (1): effects of pid controllers parameters on transient response cl response rise time overshot settling times s.s error kp decrease increase small change decrease ki decrease increase increase eliminate kd small change decrease decrease small change table (2): modified ziegler-nichols pid tuning kp ti td p 0.33 ku 0 0 pi 0.33 ku 2 tu 0 pid 0.20 ku 0.8 tu 0.2 tu table (3): ziegler-nichols tuning table for pid controller. figure 1 : closed loop control system with pid controller + + + al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٦ figure 2. depiction of rw selection figure 3 : genetic algorithms block diagram representation[9] second order first order third order fourth order fifth order respons e figure 4: fifth order plant with sensor and pid controller block diagram al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٤٧ figure 8: terminal voltage step response for fourth order model with pid controller figure 9: error signal of terminal voltage step response for fourth order model with pid controller figure 10 : error signal for terminal step response of 5th order model with gpid figure 9 : terminal voltage step response for 5th order model with gpid microsoft word 2 عباس عربي 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   حول تحسين نظام اإلنارة في معمل الصناعات الجلدية في الكوفة هموقعيدراسة الحديثة باستخدام بدائل اإلضاءة عبد العباس محسن جاسم كوفة المعهد التقني /قسم الكهرباء/مدرس مساعد موجزال األجواء أفضل توفير في المنشاة الصناعية بما يحققاإلنارةحث على مسالة رفع كفاءة منظومة بيركز ال مع تقليل صرف الطاقة الكهربائية المستخدمة فيها بما يحقق تقليل كلفة المنتج اإلنتاجالمساعدة في عملية في الكوفة في قاعات معمل الصناعات الجلديةاإلنارة تم في سياق البحث تحليل كفاءة وجودة منظومة .ونوعيته مع ها تحسينإمكانيةفي المنظومة الحالية عن المعايير القياسية واقترحت وجود انحراف نتائج البحثأظهرتوقد وال سيما في القاعات الجديدة التي تم تشييدها توفير في الطاقة الكهربائية من خالل عمل بعض اإلجراءات التقنية .لتضم الخطوط اإلنتاجية الحديثة كفاءة ،اللمعان،بهر العين ، التباين ، االستضاءة شدة ، الفيض الضوئي ، اإلضاءة قوة :كلمات االستدالل اإلضاءة practical study to improve electrical illumination system in kufa dermal industrial factory using modern illumination abed al–abass muhseen jassem assistant lecturer electrical department kufa technical institute abstract this research focuses on idea to rise quality of illumination in product halls in industrial foundation to get best product operation with reduction a product cost by reduce electrical energy needed to system. during research analysis of a illumination system in the dermal industrial factory halls that are doing shows depart from standards and abilities to improve currently system with economize electrical energy. keywords: illumination flux, contrast, illumination intensity, illumination efficiency, eye bedazzles, luminance. عباس محسن جاسمعبد ال المقدمة العاملين في المصنع سيتجنبون إنذلك ، في شركة ما اإلنتاج تحسين إلى يؤدي أن يمكن رةااإلنتحسين نسبةإن األلمانية في احد المصانع ولؤمسفقد ذكر ، غير نظامية إنارة التي يمكن حدوثها عند وجود األخطاء .]1992،يحيى [ تحسين مستوى اإلنارةدعما كانت عليه في السابق بع% 50قلت بنسبة رفض الزبائن لمنتجاته للقيام اإلنارة مختلفة من وأنواع كميات إلى فالعين تحتاج وإتقان الجيدة العيون من العمل براحة اإلضاءة تمكن يبين 1 رقم جدولال .أخر عمل ألداءكفي تعين ربما ال عمل مألداء كافية إضاءة مختلفة ونتيجة لذلك فان بإعمال .أمثلة إلعمال مختلفة مع كمية اإلضاءة المناسبة لكل منها بعد الجسم عن -2 قوة الضوء أو شدة -1 الجسم وهي إلىهناك ثالث عوامل تحدد كمية الضوء الواصلة . اإلنارة نظام توزيع -3مصدر الضوء كمية بأنه خاصيتان مميزتان للمصدر الضوئي حيث يمكن تعريف الفيض الضوئي ءةاإلضا الضوئي وقوة الفيض وحدة قياس الفيض هي .في وحدة الزمن نبعث من المصدر الضوئي في جميع االتجاهات الطاقة الضوئية التي ت .الليومن من واحد في زاوية مصدر ضوئي قيمته ليو فتقاس بالشمعة التي تعادل فيض ضوئي منبعث من اإلضاءة قوة إما :مجسمة واحدة وتحسب المعادلة من العالقة π= 4 f e (1) : حيث) ф( ويرمز لها)a( الساقط عموديا على وحدة المساحة)f( الضوئيمقدار الفيضوشدة االستضاءة هي a f =φ (2) وحدة قياس شدة االستضاءة هي اللوكس للجسم عن طريق المسافة التي تبعده عن ةالواصل شدة االستضاءة ويستخدم قانون التربيع العكسي في حساب لى سبيل المثال الجسم الذي يبعد مترين عن المصدر يحصل على ربع الكمية التي يحصل مصدر الضوء فع ] 1995، اسر[ دعليها عندما تكون المسافة متر واح في اإلضاءة تحدثمشكالت 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   69  دراسة موقعيه حول تحسين نظام اإلنارة في معمل الصناعات الجلدية في الكوفة باستخدام بدائل اإلضاءة الحديثة :ة يمكن إيجازها بالنقاط التاليةءاضتحدث بعض المشاكل في اإل . عدم وجود إنارة طبيعية في موقع العململ وانخفاض إنتاجيته مع ا الصناعية غير الكافية الذي يؤدي إلى توتر عضو البصر وبالتالي تعب العاإلنارة .احتمال ظهور أخطاء إثناء العمل / شمعة500 العامل فعندما تكون شدة اإلضاءة بحدود وإجهاد تعب البصر إلى ارتفاع وهج الضوء يؤدي أيضا عامال مضرا فممكن إن يسبب ضوء أكثر أومتر مربع / شمعة 1000 بمقدار إضاءةمربع ممكن ان تسبب متر ساطع إجهادا للعين وهذه الظاهرة تدعى ببهر العين والذي ينتج من عدم التوزيع المتجانس لنظام اإلنارة سواء على على سبيل المثال يقوم المصباح الشفاف بتسليط ضوء شديد ومباشر(بطبيعة المصدر الضوئي المستعمل .)العين بينما يقل تأثير الحالة عندما يكون المصباح مطليا بلون ابيض أو ثلجي التدني في التباين أو التباين الحاد بين مستوي اإلنارة بسبب عدم التوزيع الصحيح للمصادر ضمن وحدة . المساحة أو بسبب عدم استعمال وسائل التوزيع المتجانس مثل العواكس وغيرها . المباشر والمنعكس اللمعان .]1992،يحيى [ ارتفاع نبضات تدفق الضوء التي تسبب توترا في عضو البصر اإلنارة مختلفة من مصادر أنواع فهناك لإلنارةيمكن التقليل من الحاجة الى الطاقة الكهربائية باالستخدام الكفء 20ة نفسها فمثال يعطينا المصباح المتوهج حوالي باستخدام الطاقاإلنارةالصناعية توفر لنا كميات مختلفة من ]1995اسر ،[ .لومن لكل واط 70 لومن لكل واط من القدرة بينما يعطينا المصباح الفلوري .لكل منهايوضح المصادر الضوئية ومقدار الفيض الضوئي 2 رقم الجدول تحدد من خالل ) m(ركيبتين معلقة في السقف الفلورسنت فان المسافة المطلوبة بين تأنابيبفي حالة استخدام :بحيث) l(ارتفاع تركيبة االنارة عن سطح العمل lm ∗= 5.1 (3) اإلضاءةكفاءة من القدرة الكهربائية مقدار ما يجهزه المصدر من فيض ضوئي لكل واطبأنه يقصد بكفاءة المصدر الضوئي .الضوئية من المصادرألنواع أمثلة يبين 1الشكل رقم تتأثر سلبا مع زيادة ساعات التشغيل مما يعتبر عامال مؤثرا عند تصميم نظام )η (كفاءة اإلضاءة للمصابيح وكمثال تتأثر مصابيح ة اإلنتاجاإلنارة فعملية صيانة وتبديل المصابيح ربما تأخذ كلفة مادية وتعطيل لعملي ]ies ،2002 [. مع ساعات التشغيل2 بالشكل رقمالفلورسنت كما مبين 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  70 عباس محسن جاسمعبد ال في معمل الصناعات الجلديةاإلنارةنظام متنوعة حسب طبيعة كل خط يحتوي المعمل على قاعات تحتوي على المكائن الخاصة باإلنتاج وهي مكائن وسيتم في سياق واألبعاد وهي قاعات متماثلة البناء اإلنتاجييعة الخط تتناسب وطب خصص لها قاعات إنتاجي القاعات من ناحية المصادر الضوئية المستعملة مع بيان كمية هذه البحث دراسة نظام اإلنارة الحالية في كل من كذلك يتم في سياق المتولدة وطريقة التوزيع المستخدمة وتحليل النتائج لمعرفة المشاكل الحالية فيها واإلنارة .اإلنارة لمنظومة المصروفةالبحث حساب الطاقة الكهربائية :اإلنتاجيةة في القاعاإلنارة تحتوي على مكائن خياطة منتجات وهي 3بالشكل رقم وتطبيق البحث والمبينة لدراسة إنتاج تم اخذ نموذج لقاعة متماثلة من ناحيةألنهالقاعات بنظر االعتبار مجموع ااألخذوفي النهاية سيتم جلدية : القاعةمعطياتأهم ونظام التوزيع المعتمد وفيما يلي إلنشاءات م20*م55= القاعة إبعاد م5=ارتفاع القاعة مكينة26=13*2= المكائن في القاعة عدد متر1=المسافة بين ماكنة وأخرى سم75 =األرضارتفاع الماكنة عن متر2.3=بعد تركيب اإلنارة عن مستوى سطح األرض فلورسنتأنبوب 24 =اإلنارةعدد تراكيب الذي يوضح أيضا مواقع شبابيك اإلنارة في القاعة ومواقع 4 بالشكل رقم فهو موضح اإلنارة توزيع تراكيب أما .وأرقام نقاط الفحص التي تم اخذ القياسات عندها كانت النتائج 4 بالشكل رقم النقاط داخل القاعة والمبينة لمجموعة من اإلضاءة لشدة ألموقعيمن خالل الفحص .4رقم ما مبينة بالجدول ك والمسلطة على مكائن الخياطة غير متساوية اإلنتاجية داخل القاعة اإلضاءةمن خالل الجدول يتبين بان شدة الذي ينفذ من خالل سبعة شبابيك موجودة الطبيعية من ضوء الشمساإلضاءة مصدرها اإلضاءةبالمقدار ومعظم القريبة من ةفالماكين) متر2*6(إبعاد وكل شباك منها ذو )األبيض باللون 3بالشكل رقم الموضحة (بالقاعة الشباك تصلها كمية إنارة اعلي من تلك التي تصل لألخرى البعيدة حيث تقل هذه الكمية عن الحد المثالي وجد انحراف في .2حسب الجدول رقم ) لومن 300(وع من العمل وهو بحدود لإلضاءة المطلوب لهذا الن 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   71  دراسة موقعيه حول تحسين نظام اإلنارة في معمل الصناعات الجلدية في الكوفة باستخدام بدائل اإلضاءة الحديثة سطح الماكنة عن ) الفلورسنت(اإلنارة نجد ارتفاع تركيبة ) 3( فمن خالل المعادلة رقم اإلنارةتصميم )l=(2.3 كورة المذ المذكورة في المعادلةم مع النسبة جمتر وهذا ال ينس5 =وأخرى المسافة بين تركيبة إمامتر. من الطاقة المستهلكة في المنشأة %) 25-5(نسبته مااإلنارة الكهربائية المستهلكة في نظام الطاقةتشكل حرارة منبعثة على إلى يتحول األخر طاقة ضوئية والقسم إلىالطاقة الكهربائية يتحول جزء منها .الصناعية من الضوئية من المصادرأنواعرنة بين ثالث مقا 5الجدول رقم حرارة بالتوصيل وفي أو حراري إشعاعشكل ]proceedings , 1968[ : ناحية نسب توليدها للطاقة الضوئية والحرارة المنبعثة على التأكيدتجرى بعض التحسينات على نظام اإلنارة لغرض تقليل صرف الطاقة الكهربائية مع أن ويمكن ]guide ،1994[بل الهيئة الهندسية لإلنارة ضرورة تحقيق مستويات اإلنارة المنصوص عليها من ق (illumination engineering society ies) . والتي يتم ذكرها في التوصيات والمعداتلألشخاص العمل والسالمة العامة إنتاجيةوذلك لضمان فلورسنت ولو وبةأنب 24 أمبير وهو ناتج عن تشغيل 12 يساوي اإلنتاجيةالتيار الكهربائي المستهلك داخل القاعة داخل المعمل يكون إنتاجية داخل خمسة قاعات اإلنارةجمعنا التيار الكهربائي المصروف لتشغيل منظومات منظومات إضافة في المعمل بشكل كامل بعد لإلنارة أمبير وعند حساب التيار الكلي المصروف 60المجموع مطعم وورش الصيانة سيكون مقداره ضعف الرقم السابق والمخازن ومحطة الطاقة والاإلدارة في بنايات اإلنارة .تقريبا :الستنتاجاتا :يلي مة للمعمل تبين ماي داخل القاعات القداإلنارة من خالل النتائج التي تم قياسها وتحليلها لمنظومة . غير متساوي على وحدة المساحة داخل القاعةاإلنارة توزيع .1 .ائن الخياطة غير كافية حسب المواصفات العالمية بعض مكإلى الواصلة اإلنارةكمية .2 ما قورن بكمية التيار الكلي إذامقدار حمل التيار المسحوب داخل القاعات مقدار ال باس به .3 .اإلنتاج يشكل جزء كبير من المصروفات الكهربائية المستحقة وبالتالي زيادة كلفة هوالمسحوب للمعمل و عدا كونها تعتمد اعتمادا اإلنارة مع القاعات القديمة في سوء توزيع لإلنتاجديدة تشترك القاعات الج .4 اعتماد نظام إلى إضافة األوقات الطبيعية وهو مصدر ال يملك الوثوقية الكاملة في كل اإلضاءةمباشرا على . عتمد المعايير العلميةقدم معلقة بسقف ثانوي وبشكل توزيع لم ي )4(لحجم ا على مصابيح فلورية صغيرة اإلنارة وبهذا يمكن المصابيح الفلورية المدمجة تملك اعلى شدة اضاءة باقل استهالك للقدرة الكهربائية .5 امبير27.6 =100 /120*23=من قيمة التيار المسحوب لالنارة اي بمقدار% 23توفير ما نسبته 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  72 عباس محسن جاسمعبد ال وبحساب واط 3977.6 الى يكون الناتج مساوي0.8=وعند حساب القدرة وباعتماد معامل قدرة .6 . الدنانير لخزينة المعملآالفتسعيرة الدولة للطاقة الكهربائية يكون قد تم توفير الشكل رقمإنارة مصابيح الفلورسنت تنخفض مع زيادة ساعات العمل كما مبينة بالعالقة الموضحة ب .7 . وهذا يعطي أفضلية باستخدام المصابيح المدمجة4 التوصيات . داخل القاعاتاإلنارة تصميم نظام إعادةمعايير العلمية في اعتماد ال -1 ) عند عطل المصابيحإي(استبدال المصابيح الفلورية وبالتدريج كي ال يؤثر على الكلفة -2 التي توفرها لوحدة المساحة اإلنارة بنظر االعتبار قدرة المصابيح الجديدة وكمية األخذ مع مدمجةبمصابيح 2رقم للجدواحسب اإلنارة النازلة من السقوف الثانوية من اجل إعطاء زيادة في شدة التقليل من ارتفاع تراكيب -3 .اإلضاءة المسلطة على الماكينة صادرالم   1992 القاهرة-ئة المصرية العامة للكتاب الهي–اإلضاءة داخل المباني تأليف الدكتور يحيى حمودة -1 جامعة -كلية الهندسة – الدكتور اسر علي زكي والدكتور حسن الكشموشي تأليف اإلضاءةهندسة  -2   1995 االسكندريةدار الراتب الجامعيةإصدار اإلسكندرية العدد–دمشق المجلد الرابع والعشرون جامعة نشركفاءة وجودة الطاقة الكهربائية–الدكتور حسان سويدان -3 2008 دمشق-الثاني 4 electricity distribution network design, e.lakervi, iee, england, 1995 5 electrical installations handbook, siemens, john wiley & sons, 2002. 6 guide to energy management, william j. kennedy, fairmontpress ,inc, 1994 7 proceedings “light and sound for enginers”t.nelson and sons ltd.1968,london chapter 7.pp 144-163 8 stanley,r,c, ,special issue on light source technology, ieee, a, vol., 127, april 1980 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   73  دراسة موقعيه حول تحسين نظام اإلنارة في معمل الصناعات الجلدية في الكوفة باستخدام بدائل اإلضاءة الحديثة 9 ies lighting handbook-illumination engineering society, new york, 2002 10 schneider electric , electrical installation, france, 2007 ]1[ المناسبة لكل عملاإلضاءةمقدار 1جدول رقم قاعة رسم هندسي مكائن خياطة ورشة إعمال دقيقة غرفة طابعة ورشة تصليح صالة عمليات مستشفى صالة المطالعة نوع العمل 300 )لوكس(مقدار اإلضاءة 180 300 200 250 300-500 300 ]3[نماذج لمصادر ضوئية والفيض الضوئي لكل منها 2جدول رقم 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  74 عباس محسن جاسمعبد ال ]guide ،1994[ الكفاءة الضوئية لمجموعة من المصادر الضوئية3جدول رقم المصدر الضوئي )وات(القدرة )وات/ليومن(كفاءة المصباح 17 100 standard incandescent filament 20 300 linear tungsten-halogen 90 32 fluorescent t-8 , 4 ft 70 26 cfl 45 175 mercury vapor 80 400 metal-halide ,high-wattage 50 1000 high pressure mercury lamp 90 70 high pressure sodium ,low wattage 100 250 high pressure sodium , high wattage 30 1000 xenon short arc lamp 125 80 compact floresent lamp :كمية اإلضاءة في نقاط الفحص 4الجدول رقم رقم نقطة الفحص 1 2 3 4 5 6 7 8 9 )لوكس(اءةشدة اإلض 67 120 185 255 275 250 150 290 170 ]7[ نسب تحول الطاقة الكهربائية في المصادر الضوئية 5الجدول رقم %حرارة بالتوصيل المصدر الضوئي %الطاقة الضوئية %إشعاع حراري مصباح التوهج 16 72 12 فلورسنت 22 28 50 فلوري مدمج 32 24 44 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   75  دراسة موقعيه حول تحسين نظام اإلنارة في معمل الصناعات الجلدية في الكوفة باستخدام بدائل اإلضاءة الحديثة ]5[ المصادر الضوئيةأنواع 1الشكل رقم ]9[.كفاءة اإلضاءة مع ساعات التشغيل 2 ل رقمالشك 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة  76 عباس محسن جاسمعبد ال متر55 توزيع المكائن في القاعة القديمة 3 الشكل رقم توزيع اإلنارة في القاعة 4الشكل رقم 2012 لسنة 77-68 الثاني، العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة   77 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 558 reuse of treated sanitary sewage in najaf city for agricultural purposes asst.prof dr.saleh issa khassaf university of kufa /college of eng ass.let fatima mohsen kizar university of kufa /college of eng. abstract sanitary sewage treatment plants can be considered as a source for water that can be used for different purposes. the agricultural sector is a steady and very big potential consumer of reclaimed water . so , treated sewage reusing in agricultural purpose is a good goal where it requires simpler treatment in comparison with other purposes in this study , the quality of treated sewage in najaf sewage treatment plant have been evaluated and compared with standard specifications of america, egypt and iraq water quality that used for agricultural purposes. the evaluation process includes samples collection from effluent of treatment plant for a period of (12) months from january 2009 to january 2010. then measuring the quality of treated sewage which includes measurement of biochemical oxygen demand (bod), suspended solid (s.s) ,total dissolved solid (tds), and ph .also concentration of chemical elements which may cause harmful effect on plants like cl, based on the results of this study it was found that: (1) biochemical oxygen demand, suspended solid , total dissolved solid and ph values of effluent treated sewage of all date of measurement are within the maximum allowable range according to the egyptian standards and american standards. (2) the concentrations of values of chlorine (cl),sulphate (so4), phosphate (po4), sodium (na) and calcium(ca) are :83%, 75%, 100%, 75%, 92% respectively are less than the egyptian allowable rang while 75% of magnesium (mg) values are exceeding the allowable limit. (3) tds, ph, po4, no3 and ca values of effluent treated sewage of all data of measurement are within the iraqi allowable range. (4) the concentration values of bod, s.s, na and mg are 58%, 75%, 75% and 1% respectively are less than the iraqi allowable range. (5) no sodicity problem in the soil as a result of the use of treated water effluent from najaf sewage treatment plant. key words: sewage , agricultural , wastewater , treatment , bod , najaf al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 559 إعادة استعمال مياه الصرف الصحي المعالجة في محطة معالجة المياه الثقيلة في مدينة النجف لإلغراض الزراعية كلية الهندسة/ صالح عيسى خصاف جامعة الكوفة .د.م.أ كلية الهندسة/ ر جامعة الكوفة فاطمة محسن كزا. م.م المستخلص : القطـاع . يمكن اعتبار مياه الصرف الصحي مصدرا للمياه التي يمكن اسـتخدامها لألغـراض المختلفـة لذلك إعادة استخدام مياه الصرف الـصحي المعالجـة لألغـراض , الزراعي هو المستهلك الكبير للمياه المستصلحة . يتطلب معالجة بسيطة قياسيا بالمعالجات المطلوبة لإلغراض األخرى الزراعية هو هدف جيد حيث في هذه الدراسة تم تقييم المياه المعالجة في محطة النجف ومقارنتهـا بالمواصـفات القياسـية المـستخدمة . لألغراض الزراعية حيث تم مقارنتها بالمواصفات المصرية واألمريكية والعراقية شـهرا مـن ) 12( جمع العينات من المياه المعالجة الخارجة من محطة النجف لفترة عملية التقييم تتضمن م ومن ثم تم قياس نوعية المياه المعالجة والتي تشمل المتطلب الحيـوي 2010م إلى كانون الثاني 2009كانون الثاني كيز بعض العناصر الكيمياوية التـي األس الهيدروجيني وقياس تر , المواد الذائبة الكلية , المواد العالقة , لألوكسجين . لها تاثيرات ضارة على النباتات مثل الكلور المـواد , المواد العالقة , قيم المتطلب الحيوي لألوكسجين -1اعتمادا على نتائج هذه الدراسة يمكن استنتاج ات هي ضمن الحـدود المـسموحة الذائبة الكلية واألس الهدروجيني للمياه المعالجة الخارجة من المحطة ولكل القياس ) الصوديوم والكالـسيوم , الفوسفات , الكبريتات , الكلور ( قيم تراكيز -2. حسب المواصفات المصرية واألمريكية من قـيم % 75على التوالي اقل من الحدود المصرية المسموحة بينما % 92، % 75، % 100، % 75، % 83هي قيم االمالح الذائبة الكلية، االس الهيدروجيني، الفوسفات، النتـرات والكالـسيوم -3. المغنيسيوم تتجاوز الحد االعلى قـيم -4. للمياه المعالجة الخارجة من المحطة ولكل القياسات هي ضمن الحدود المسموحة حسب المواصفة العراقية علـى % 1، % 75، % 75، % 58تراكيز المتطلب الحيوي لالوكسجين، المواد العالقة، الصوديوم والمغنيسيوم هي ال توجد مشكلة صودية في التربة نتيجة اسـتخدام الميـاه المعالجـة -5. التوالي اقل من الحدود العراقية المسموحة .الخارجة من محطة معالجة مياه الصرف الصحي في النجف al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 560 nomenclature bod5 biochemical oxygen demand s.s suspended solids tds total dissolved solids mg/l milligrams per liter sar sodium adsorption ratio ca calcium na sodium mg magnesium nstp najaf sewage treatment plant ds/m decisiemens per metre introduction water is an important element of the three environment elements (air ,water, soil) because it being directly linked to the lives of living organisms . it is known that water covers more than threequarters of the globe, but despite all this, good for use remains slightly with the increasing need for it . in later times the world know water crisis ,as a result of waste water and poor distribution of this wealth in addition to the climatic conditions that helped to exacerbate this crisis and its spread (abdul alla , 2010). water –related problems are increasingly recognized as one of the most immediate and serious environmental threats to human kind water use has more than tripled globally since 1950,and one out of every six persons does not have regular access to safe drinking water. lack of access to a safe water supply and sanitation affects the health of 1.2 billion people annually(who and unicef,2000) .the latest global environment outlook of the united nations environmental programme(unep)reports that about one third of the worlds populations currently live in countries suffering from moderate to high water stress, where water consumption is more than 10%of renewable fresh water resources (unep,2002a) faced with these challenges ,there is an urgent need to improve the efficiency of water consumption ,and to augment the existing source of water with more sustainable alternatives .numerous approaches ,modern and traditional ,exist throughout the world for efficiency improvements and augmentation .among such approaches, wastewater reuse has become increasingly important in water resource management for both environmental and economic reasons. wastewater reuse has a long history of applications, primarily in agriculture, and additional areas of applications ,including industrial household and urban are becoming more prevalent of them all, wastewater reuse for agriculture still represents the large reuse volume ,and this is expected to increase further particularly in developing countries(unep,2002a) the most common reasons for establishing a wastewater reuse program is to identify new water sources for increased water demand and to find economical ways to meet increasingly more stringent discharge standards(caigan,2005). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 561 the main objective of this study is to evaluate the quality of treated sewage in najaf treatment plant and then to study the possibility of treated sewage reuse for agricultural in najaf city. the goals of reuse a waste water the use of treated sewage for agriculture purposes is an important goal because of : 1population growth and the subsequent growing demand for food production leads to increased demand for irrigation water(on a global scale irrigation water represents about 70%of the total water demand)and in some countries reaches up to 85%. therefore ,the agricultural sector is a steady and very big potential consumer of reclaimed water. 2the presence of nutrients in the wastewater offers an additional benefit ,although often overestimated when compared to the importance of the water presence 3the large water quantities needed in combination with the fairly uniform quality standards required, favor agricultural reuse projects connected to centralized wastewater treatment facilities, which are often located in the vicinity of the irrigated areas. 4 the required quality characteristics of the reclaimed water for irrigation can be achieved through reasonable treatment ,which can vary depending on the method of irrigation and the adoption of additional measures. often this treatment is provided irrespectively of irrigation, in compliance with effluent discharge regulations .the need for additional treatment may arise for certain irrigation practices , but even in these cases the associated costs can be reasonable 5during irrigation soil offers additional treatment , by removing pollutants , which would otherwise end up in surface water or the ground water. the quality of treated sewage used in agriculture has a great influence on the operation and performance of sewage treatment plants .generally , the required quality of effluent is depended on the crops to be irrigated , the soil conditions and the adopted system of effluent distribution(alya ,2008) the area study najaf sewage treatment plant is located in albrakia region , which lies about (3) kilometers from the center of kufa city . the project serves 25%of the population , but with enough space to allow future expansion to secure the city's needs for the future. the location of the study area is shown in figure. (1). najaf city is a holy city , therefore is expected to host many visitors on religious occasions and it was chosen as the capital of islamic culture for the year 2012, so it is very important to ensure the viability of a project to receive this extra load . nstp( najaf sewage treatment plant ) is designed to receive load of 140000 citizens and the characteristics of final flow to be (20mg/l) of bod and (30mg/l) of s.s. the highest rate of flow is 27000m3/day. wastewater in many parts of najaf city is pumped through the network by the pumping stations to the project which contains preliminary , primary and secondary treatment in addition to chlorination and treatment of sludge. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 562 because of temperature rise in the countries of the middle east , including iraq , sewage are in the case of sepsis and gases cause buoyancy minutes sludge in the primary treatment , thus reducing the level of performance in this treatment. secondary treatment is done through the membranes by the natural ventilation of the biological filters (trickling filters). through the work of biological filters bacteria grow on pollutants found in wastewater but remains constant in number to support filter filling . bacteria get the air from the atmosphere as a result of temperature difference between the sludge and air , which leads to airflow within filter charges . bectel company has improved the effectiveness of secondary treatment to improve the quality of effluent treatment plant through the program of iraq reconstruction. chlorination process has been shut down because of that the addition of chlorine to water containing organic material cause cancer. there are two sources of surplus sludge in najaf station: excess sludge of the aeration tank resulting from the growth of bacteria and the quantity of sludge deposited in the initial tank . then sludge is pumped to thickener tank and then to drying beds that are built entirely of concrete and when dry will be raised and removed permanently . the flow chart of the nstp is shown figure(2) finally , the treated effluent water is disposaled to shatt al-kufa , but within the specifications set out in table(1) (palmer, 2004) standards of irrigtion water accordıng to the egyptian water qualıty for agrıcultre use ın egypt. these specıfıcatıon of water irrıgatıon were classıfıed ın table (2) and (3) according to standard specification of american water quality for agriculture. these specification were classified in table(4). results and discussion in this study the evaluation and visibility results of using the treated sewage in nstp for agricultural purposes are presented . tow aspects were considered in the evaluation process . these aspects include the quality of treated sewage and concentration of chemical elements. evaluating the quality of raw sewage. the quality of raw sewage was evaluated based on sewage samples drawn from the effluent of nstp . the parameters used to define the quality of raw sewage are biochemical oxygen demand(bod5) , suspended solid(s.s), total dissolved solids(tds) and (ph) . the obtained results are as shown in table(6) . the results were compared with relevant standards of sewage use for agricultural purposes . to satisfy this goal , the egyptian standards(ecp 501-2005)and american standards were used . the data collection program was extended over a period of twelve months from january 2009 to january 2010. figures (3) , (4) , (5) and (6) show the histogram of the variation of the measured parameters over the sampling time. the upper and the lower values of standard parameters as suggested by the egyptian code were dully superimposed. the upper limit represents type (c) of treated sewage which is suitable only for wooden trees plantation , while the al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 563 lower limit represents type (a) of treated sewage which can be used to irrigate peeled fruit and sport field. the data given in table(6)were compared with egyptian standards and american standards .the results of comparison in effluent of nstp given figures (3),(4),(5) and(6).in these figures ,it can be noticed that: 1-bod5 values of effluent treated sewage of all data of measurement are within the maximum allowable range figure(3).50% of bod5 effluent within type (a)of treated sewage which can be used to irrigate peeled fruit and sport field.25% of bod5 effluent within type(b)of treated sewage which can be used to irrigate fodder crops, fruit produced for packaging such as ( lemon , mango and olive) and fiber crops such as flax the remaining of bod5 effluent within the type(c)of treated sewage which can be used to irrigate wooden trees plantation. 2-s.s values of effluent treated sewage of all data of measurement are within the maximum allowable range figure(4) 8% of s.s effluent within type(a)75% of s.s effluent within type(b) and 17%of s.s effluent within type(c) 3-tds values of effluent treated sewage of all data of measurement are within the maximum allowable limit figure(5) 4-ph values of effluent treated sewage of all data of measurement are within the maximum allowable limit figure(6) chemical elements the chemical elements of raw sewage in nstp were evaluated based on their concentration in treated sewage in the effluent of the plant. these elements include :chlorine(cl), sulphate(so4), phosphate (po4),nitrate(no3) sodium(na),magnesium(mg)and calcium(ca) the collected data regarding concentration of chemical element of treated sewage effluent are shown in table(7) data collection program was extended over a period of twelve months(from january 2009 to january 2010).these data were compared with the egyptian standards .the results of comparison are as given in figures(7),(8),(9),(10), (11) ,(12) and(13)in this figures it can be noticed that: 1the obtained values of chlorine concentration at different time are as shown in figure(7) . these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (400 mg/l) , so as shown in this figure (83%) of the values are less than the allowable. 2the obtained values of sulphate concentration at different time are as shown in figure(8). these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (500mg/l) , so as shown in this figure (75%) of the values are less than the allowable. 3the obtained values of (po4) concentration at different time are as shown in figure(9) . these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (30 mg/l) , so as shown in this figure all of the values are less than the allowable , therefore , the treated sewage quality is allowed for agriculture. 4the obtained values of nitrate concentration at different time are as shown in figure(10) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 564 5the obtained values of sodium concentration at different time are as shown in figure(11). these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (230mg/l) , so as shown in this figure (75%) of the values are less than the allowable. 6the obtained values of magnesium concentration at different time are as shown in figure(12) . these values were compared with the maximum allowed concentration in sewage using for agriculture purpose which is (100mg/l) , so as shown in this figure ( 75 % ) of the values are exceeding the maximum allowable limit . 7the obtained values of calcium concentration at different time are as shown in figure (13) . these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (230mg/l) , so as shown in this figure (92%) of the values are less than allowable. the data also were compared with iraqi standards. the results of comparison are: 58% of bod values are within the iraqi standards. 75% of s.s values are within the iraqi standards. 100% of tds values are within the iraqi standards. 100% of ph values are within the iraqi standards. 100% of po4 values are within the iraqi standards. 100% of no3 values are within the iraqi standards. 75% of na values are within the iraqi standards. 1% of mg values are within the iraqi standards. 100% of ca values are within the iraqi standards. sodicity problem rhoades method (rhoades, 1977) was adopted to predict soil permeability and structural stability for soil by comparison of sodium adsorption ratio percentage and ec combinations . the values of sar and ec of treated sewage in nstp were measured over all study period (from jan. 2009 to jan.2010),the obtained results are shown in table (8) . in figure (14) rhoades method was applied to predict soil permeability from using treated sewage for agricultural , since all of the values fall to the right of the critical line , the wastewater for all months were not expected to cause loss of soil permeability. conclusions based on the results of this study the following conclusions can be drawn. 1. bod5 , s.s , tds and ph values of effluent treated sewage of all data of measurement are within the maximum allowable range . therefore this treated sewage can be used for agricultural purposes to irrigate some crops such as : limitation crop bod(mg\l) s.s(mg\l) shade trees less than 20 less than 20 fodder crops less than 60 less than 50 flax less than 60 less than 50 camphor less than 400 less than 250 castor less than 400 less than 250 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 565 2. the concentration values of cl , so4 , po4 , na , mg and ca are : 83% of cl values are less than the allowable 75% of so4 values are less than the allowable 100% of po4 values are within the allowable 75% na values are less than the allowable 92% of ca values are less than the allowable 75 of mg values are exceeding the maximum allowable limit 3. tds, ph, po4, no3 and ca values of effluent treated sewage of all data of measurement are within the iraqi allowable range. 4. the concentration values of bod, s.s, na, and mg are: 58% of bod values are less than the allowable. 75% of ss values are less than the allowable. 75% of na values are less than the allowable. 1% of mg values are less than the allowable. 5. sometimes , the specification of the water effluent from the treatment plant is higher than the environmental limits allowed to throw in the river but within the limits and specifications of water used for agricultural purposes in that case better to use this water for agricultural to provide water and to preservate the characteristics of the river on the other hand 6. no sodicity problem in the soil as a result of the use of treated water effluent from najaf sewage treatment plant according to application of rhoades method. references: • alya,a.m : a study on the reuse of primarily treated sanitary sewage for agricultural purposes: a case study of basra , 2008 • caigan, m. : wastewater reuse conserves water and protects waterways , www.nesc.wvu.edu,2005. • palmer , s.j : najaf wastewater treatment plant operation and maintenance manual , bechtel international systems , inc. ,2004 • rhoades, j.d .:potential for using saline agricultural drainage waters for irrigation, proc. of water management for irrigation and drainage, asce/reno, nevada,1977. • united nations environment programme (unep) : state of the environment and policy perspective : 1972 – 2002 , global environment outlook 3 , pp.150-179, division of early warning and assessment (dewa), kenya , 2002a. • world health organization (who) and united nations children's fund(unicf) : global water supply and sanitation assessment 2000 ,usa,2000 المصادر العربیة: )بحث منشور في االنترنیت ( "دور المیاه في نشوء الحضارات "2010, عبد اهللا موسى • e//:file:/ دور المیاه في نشوء الحضارات 53النبأ | جدید الكتب htm. http://www.nesc.wvu.edu,2005 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 566 ود المصري الستخدام میاه الصرف الصحي المعالجة في مجال الزراع ة ك ود رق م الك) 2005(أمیمھ احمد , صالح الدین • المركز القومي لبحوث اإلس كان , جمھوریة مصر العربیة وزارة اإلسكان والمرافق والمجتمعات العمرانیة " 501-2005 والبناء دخل میاه التبری د ف ي محط ة كھرب اء التقریر األولي لمشروع دراسة ومعالجة القواقع في م ) 1999(صالح إسماعیل , نجم • .جامعة البصرة/ المكتب االستشاري الھندسي " النجیبیھ في البصرة .مسودة نظام المحددات الوطنیة الستخدام میاه الصرف الصحي المعالجة في الري الزراعي) 2010(وزارة البیئة • table(1) specification of effluent water of nstp allowed to disposal in shatt al-kufa limit parameter < 40 mg/l biochemical oxygen demand bod mg/l < 60 suspended solids s.s < 100 mg /l chemical oxygen demand cod < 3mg/l po4 <50mg/l no3 table (2) wastewater standards for agrıcultural irrıgatıon ın egypt . (salah aldeen,2005) level of treatment parameter *level a **level b ***level c bod (mg/l)1 <20 <60 <400 max.physical and chemical characteristic for the effluent s.s (mg/l) <20 <50 <250 1after infiltration * level a is optimum level which can be reach by developing secondary unit to include infiltration , disinfection , etc . and because of high cost of this type of treatment , it used for special cases if it is needed **level b is secondary treatment which can be obtain from the established unit in egyptian town and village , which used any one of the following ways according to egyptian code in design and be forming units of wastewater treatment: activated sludge. oxidation ditches. trickling filters. stabilization ponds. ***level c is the treatment which the water quality result from screen and primary unit (sedimentation tank). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 567 table(3) levels of chemical elements for wastewater treatment and using for agricultural irrigation in egypt.(salah aldeen,2005) element long term maximum concentration(mg/l)(1) short term maximum concentration(mg/l)(2) total po4 _ 30 cl _ 400 so4 _ 500 na 230 230 mg 100 100 ca 230 230 (1) possibility of continuous use of water and for all soil type. (2) possibility of use water for period reaches 20 years in fine soil either alkaline or neutral. table (4) water quality for irrigation purposes. (najem, 1999) symbol limiting value ph 4.5 – 9.0 no3 unknown tds 2000-5000 mg/l(tol.crops) 500-1000 mg/l (sans.crops) table (5) wastewater standards for agricultural irrigation in iraq (ministry of environment, 2010) symbol limiting value bilateral treatment bod 40 s.s 40 tds 2500 ph 6-8 po4 25 no3 50 ca 450 mg 80 na 250 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 568 table (6) quality of effluent raw sewage in najaf city treatment plant 4.5 – 9** 6-8*** 500 – 5000** 2500*** 20 – 250* 40*** 20 – 400* 40*** standard of irrigtion water ph mg/l tds mg/l s.s mg/l bod5 mg/l concentrations date of measurement 7.5 2138 36 90" jan. 7.6 1811 39 77" feb. 7.53 1960 39 47.9" mar. 7.4 1775 23 55" apr. 7.54 1780 38 19 may. 7.5 1860 54 163" jun. 7.5 2133 48 4.3 jul. 7.7 2074 26 8.4 aug. 7.5 1041 40 5.21 sep. 7.61 1960 29 20 oct. 7.6 1934 69 18.93 nov. 7.5 1832 4 16.7 dec. 7.54 1858.167 37.083 43.787 average *egyptian standard limits **american standard limits *** iraqi standard limits. "high concentration of bod in the water effluent from the treatment plant because of the excesses of some industrial plants and hospitals to sewer al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 569 table (7) concentration of chemical element of effluent treated sewage 230 mg/l 450** 100 )mg/l( 80** 230 mg/l 250** unknown 50** 30 mg/l 25** 500 mg/l 400 mg/l standard of irrigation water ca mg na no3 po4 )mg/l( so4 ( ) mg/l cl )mg/l( concentration of chemical elements date of measurement 208 175.7 127.5 40.04 1.23 171.2 357.6 jan. 240 475.8 448 7.3 1.507 200.3 342.9 feb. 160 292.8 160 16.2 1.88 710* 450.7 mar. 164.04 136.6 155 6.8 1.459 303.9 436 apr. 165 100 175 9.923 0.765 350 303.7 may. 123 112 180 9.61 10.94 400 348.2 jun. 132 178.1 270 10.50 4.90 450 362.5 jan. 160 109.8 190.8 8.7 0.67 500 352 aug. 168 75.6 376 8.7 0.27 440 347.88 sep. 156 148.8 220 16.43 1.55 900* 321.4 oct. 145 98 195 8.7 54. 850* 323.3 nov. 165 104 200 10.80 1.56 450 317.4 dec. 165.5 167.3 224.77 12.81 2.273 477.1 355.3 aver. *high concentration of so4 in the water effluent from the treatment plant because of the excesses of some industrial plants and hospital to sewer ** iraqi standard limits. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 570 table (8): monthly sar and ec values of effluent treated sewage in najaf city treatment plant date of measurement ec ds/m sar* jan. 3.341 9.2 feb. 2.453 23.7 mar. 3.063 10.6 apr. 2.572 12.6 may. 2.781 15.2 jun. 2.906 16.61 jul. 3.333 21.7 aug. 3.241 16.43 sep. 1.627 34.07 oct. 3.063 17.8 nov. 3.022 17.69 dec. 2.863 17.25 sar= al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 571 figure(1) the location of the study area area study al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 572 figure (2) flowchart of nstp biological treatment trickling filters screen primary settlıng tank grıt chamber secondar y settlıng tank disinfection unit sludge thickener digestion dewatering system raw sewage plant effluent sludge to disposal al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 573 figure ( 3 ) comparison of standard bod5and present bod5 in effluent of nstp figure ( 4 ) comparison of standard s.s and present s.s in effluent of nstp al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 574 figure ( 5 ) comparison of standard tds and present tds in effluent of nstp figure (6) comparison of standard ph and present ph in effluent of nstp al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 575 figure (7) comparison of standard concentration of cl and present concentration of cl in effluent of nstp figure (8) comparison of standard concentration of so4 and present concentration of so4 in effluent of nstp acceptable egyptian standard levels acceptable egyptian standard levels al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 576 figure (9) comparison of standard concentration of po4 and present concentration of po4 in effluent of nstp figure (10) comparison of standard concentration of no3 and present concentration of no3 in effluent of nstp acceptable egyptian standard levels al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 577 figure (11) comparison of standard concentration of na and present concentration of na in effluent of nstp figure (12) comparison of standard concentration of mg and present concentration of mg in effluent of nstp acceptable egyptian standard levels acceptable egyptian standard levels al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 578 figure (13) comparison of standard concentration of ca and present concentration of ca in effluent of nstp figure (14) comparison of sar-ec combinations produced with use of effluent treated sewage in nstp with those associated with adequate and inadequate soil permeability acceptable egyptian standard levels zone of sodicity zone of no-sodicity hazards template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 191 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. operational analysis of isolated signalized intersections using three traffic softwares shamil ahmed flamarz al-arkawazi, building and construction engineering department, university of garmian/ kurdistan region-iraq. email: shamil.flamarz@garmian.edu.krd received on 25 january 2017 accepted on 4 april 2017 abstract: the operation analysis of isolated signalized intersection provides valuable and important information about the performance of transportation system in the city. the signalized intersections are major elements and critical points within the city transportation network; therefore accurate detailed information and data about the capacity and operation performance of the signalized intersections is very important and more significant to evaluate and improve the capacity of the transportation system and network of the city. highway capacity manual (hcm) model is widely used for operation analysis of the isolated signalized intersections in iraq through number of traffic analysis software tools which uses the hcm delay model. the most popular and widely used among traffic analysis software tools are; hcs 2010, sidra 5.1 and transyt-7f release 11. the objective of this study is a comparison between these three traffic analysis software tools based on evaluation of the quality of their operation analysis and optimization capabilities of isolated signalized intersections in order to be a good guide for the traffic engineers to decide which of these tools provide better results in evaluating the quality of isolated signalized intersections operation performance and optimizing intersection parameters. to achieve this objective, bukhari signalized intersection in kalar city was selected and the required data for the study purposes were collected. based on results of this study sidra 5.1 is the most effective and the richest operation analysis and optimization software among the three selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11. keywords: signalized intersection, operation analysis, optimization, hcs 2010, sidra 5.1, transyt-7f 1. introduction traffic software tools are widely used in operation analysis of the isolated signalized intersections in iraq through number of traffic analysis softwares which uses the hcm delay model. the most popular and widely used among traffic analysis software tools are; hcs 2010, sidra 5.1 and transyt-7f. a comparison between these three traffic analysis software tools based on evaluation of the quality of their operation analysis and optimization capabilities of isolated signalized intersections can be a good guide for the traffic engineers to decide which of these tools provide better results in evaluating the quality of isolated signalized intersections operation performance and optimizing intersection parameters. some major and basic information about the three software tools; hcs 2010, sidra 5.1 and transyt-7f are summarized in table 1 (mctrans 2008; mctrans 2012; sidra solutions 2012). mailto:shamil.flamarz@garmian.edu.krd al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 192 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 1. major and basic information about the three software tools; hcs 2010, sidra 5.1 and transyt7f traffic software tool developed by traffic software tool function (related to signalized intersection) simulation run output results optimization run output results references hcs 2010 mctrans center, university of florida signalized intersection capacity and los. the analysis\isolated signalized intersection\up to 4 approaches for each intersection. its simulation run outputs includes; degree of saturation, uniform delay, incremental delay, control delay, intersection delay and los its optimization run output results include; optimized cycle length, degree of saturation, uniform delay, incremental delay, control delay, intersection delay and los (mctrans 2012) sidra 5.1 akcelik & associate s pty ltd, australia tool for isolated intersection performance and timing analysis \isolated signalized intersections\up to 8 approaches for each intersection. its simulation run output results include very important measures of effectives such as; degree of saturation, total and average delay, los, performance index (disutility index), fuel consumption, emissions, and operating costs its optimization run output results include; optimized cycle length, degree of saturation , total and average delay, los, performance index (disutility index), fuel consumption, emissions, and operating costs (sidra solutions 2012) transy t-7f release 11 mctrans center, university of florida is a traffic simulation and signal timing optimization program\from 1 to 99 signalized intersection (work from the range of one intersection as isolated signalized intersection and up to 99 signalized intersections as a network)\ up to 4 approaches for each intersection. its simulation run output results include very important measures of effectives but with less range of outputs than sidra 5.1, the outputs include; degree of saturation, uniform delay, random delay, total delay, average delay, los, performance index (disutility index) and fuel consumption. its optimization run output results include; optimized cycle length, control delay, fuel consumption and performance index (disutility index) (mctrans 2008) to estimate delay time at two important intersections at palestine street in baghdad city the capital of iraq, the two traffic software tools; highway capacity software (hcs) and the signalized and unsignalized intersection design and research aid (sidra) software were used. the analysis results of the two softwares; hcs and sidra showed that, the hcs gives different delay time values than sidra by a small percent and the sidra model can be improved significantly and used for traffic analysis in baghdad conditions by calibrating the basic saturation flow rate (jameel 2011). a research carried out in jordan to check out the validation of the two traffic software tools; the highway capacity software (hcs) and the signalized and unsignalized intersection design and research aid (sidra) software which are widely used for estimating delay at signalized intersections in jordan. the analysis results of the two softwares; hcs and sidra showed that, for low delay ranges, hcs tends to slightly over-estimate control delay; while sidra has a predicted control delay that is in good agreement al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 193 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. with the field data. at higher delay levels, hcs has noticeable scattered predictions as compared to field data with more tendencies to over-estimation, while sidra provides less scattering than hcs. however, sidra showed a better performance than hcs (al-omari, b., ta’amneh 2007). the analysis results of comparison study between the three traffic software tools; transyt-7f, synchro and hcs based on signalized intersection delay estimation for 8 signalized intersections in seattle, washington, united states showed that, each program has its strengths and weaknesses, and neither is ideal for every situation. the analyst should carefully consider how each program’s characteristics mesh with the study-section characteristics and project objectives when making a decision as to which program to use for a particular study (washburn, s., larson, n. 2002). this study compares three traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 based on the evaluation of the quality of their operation analysis and optimization capabilities of isolated signalized intersections. evaluation includes testing how well these traffic analysis software tools estimate or predict signalized intersections; degree of saturation, delays, queue lengths, queue spillback, fuel consumption, disutility index, levels of service, and optimization capabilities. 2. hcm2000 and hcm2010 editions signalized intersections control delay models hcm model is widely used for operation analysis of the signalized intersections in iraq and worldwide through number of traffic analysis software tools which uses the hcm delay model. among the most popular and widely used among traffic analysis software tools are; hcs 2010, sidra 5.1 and transyt-7f release 11. mctrans as part of its software maintenance developed and maintained the highway capacity software (hcs) as a faithful implementation of the hcm procedures. since its first issue to mctrans, additional extensive versions to the computational code are made. the hcm 2010 is the basis for the los and capacity computation included in hcs (mctrans 2012). sidra 5.1 was released in march 2011, in coincided with the release of highway capacity manual 2010. it included the highway capacity manual 2010 los methods, delay models and default parameters were adopted. sidra 5.1 included large enhancements to traffic models, user interface and program features (sidra solutions 2012). transyt 7f uses the hcm 2000 delay model, but also uses macroscopic simulation results to allow hcm 2000 delay model to recognize complex traffic operations (mctrans 2008). 3. study area kalar city is the center of kalar district located in the northeast of iraq and northeast of capital of iraq baghdad with 220 km approximate distance, and it is one of sulaimaniya governorate districts and lies on sirwan (diyala) river. currently kalar city is the center of garmian area administration, the population of kalar city is (197,230 persons) which represent (74%) of kalar district population according to information collected by garmian directorate of statistics. kalar now is in a continuous progression toward further urban expansion and infrastructural growth due to its location which connects iraq, iran and kurdistan together. the rapid and big increase of kalar city population is the major cause of the increasing demand for suitable and adequate transportation system and traffic network in terms of capacity and mobility to avoid the major operation problems especially during the peak periods. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 194 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4. case study as a case study a major congested signalized intersection (bukhari intersection) has been selected. bukhari signalized intersection has congested traffic and represents significant traffic facility in kalar city traffic system because it’s important location, where it is located next to the presidency of university of garmian and connect kalar-kefri districts multi lane two-way highway with the center of kalar city (see figures 1 and 2). figure 1. bukhari signalized intersection existing geometric design figure 2. map of kalar city locating bukhari signalized intersection (google maps) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 195 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. data collection in order to evaluate the operation performance of the selected isolated signalized intersection (bukhari intersection) using; traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 field observation including traffic volumes, geometric data and other required data should be collected. the data collection is done manually and using video records on working days during the highest congestion of the transportation system at peak hours. 5.1. traffic volume traffic volume count carried out at bukhari intersection during the peak period (the peak period is selected based on the personal observation and information from the garmian traffic police directorate) from (8:25 a.m to 9:25 a.m) using video record (see figure 3) during the working day on 17 th of july 2016. the highest traffic volume in each direction is recorded to be used in the analysis of the present study. figure 3. bukhari intersection signalized intersection-traffic volume count using video record the traffic volume counting period is divided into 15 minutes intervals; table 2 shows the total volume for all approaches in bukhari signalized intersection. 6. results and disscusion the rules for editing the document briefly describe the characteristics of form elements of the document content operation analysis (simulation runs) and optimization of bukhari isolated signalized intersection using; traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11: 6.1. operation analysis (simulation runs) of bukhari signalized ntersection using; hcs 2010, sidra 5.1 and transyt-7f release 11 software tools for the evaluation purposes of the selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 which are currently widely used in iraq in term of their results of isolated signalized intersections operation analysis. a simulation runs applied on bukhari isolated signalized al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 196 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. intersection using the selected three softwares and the major output results of the three simulation runs of the three selected softwares are summarized in tables 3, 4 and 5 table 2. traffic volume, peak hour factor (phf), phases sequence and signal timing at bukhari signalized intersection for all approaches in the peak hour period collected data nb sb eb wb th lt th lt th lt th lt movement no. 101 102 103 104 105 106 107 108 t ra ff ic v o lu m e 8:25-8:40 a.m (15 min.) 16 52 37 17 71 4 180 96 8:40-8:55 a.m (15 min.) 26 48 38 8 120 4 89 60 8:55-9:10 a.m (15 min.) 19 51 29 10 91 1 116 84 9:10-9:25 a.m (15 min.) 14 63 17 4 110 6 95 49 8:25-9:25 a.m (1 hour) 75 214 121 39 392 15 480 289 hv 0 6 1 0 24 0 50 8 hv% 0 3 1 0 6 0 10 3 phf 0.72 0.85 0.80 0.57 0.82 0.63 0.67 0.75 signal timing (sec) g=20 y=5 all red=2 g=25 y=5 all red=2 g=25 y=5 all red=2 g=30 y=5 all red=2 phases sequence th= through movement, lt= left movement, and % hv=percent of heavy vehicles table 3. operation analysis (a simulation run) major output results for bukhari signalized intersection using hcs 2010 operation analysis outputs eastbound westbound northbound southbound lt lt lt lt lane group degree of saturation (%) 92 170 44 33 lane group uniform delay (sec) 53.2 51.5 41.9 44.3 lane group incremental delay (sec) 23.6 323.6 1.8 1.3 lane group control delay (sec) 76.8 375.1 43.7 45.6 lane group los e f d d approach control delay (sec) 76.8 375.1 43.7 45.6 approach los e f d d intersection delay (sec/veh) 219 intersection los f al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 197 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. bukhari signalized intersection operation analysis major outputs resulted from the simulation runs of the selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 show that:  sidra 5.1 is the richest operation analysis software to measure the effectiveness of isolated signalized intersections. its simulation run output results include very important measures of effectives such as degree of saturation, total and average delay, los, performance index (disutility index), fuel consumption, emissions, and operating costs (see table 4).  transyt-7f is providing similar to sidra 5.1 valuable and significant simulation run output results but less wide range, where its simulation run output results include very important measures of effectives such as degree of saturation, uniform delay, random delay, total delay, average delay, los, performance index (disutility index) and fuel consumption (see table 5).  hcs 2010 provides operation analysis output results include some major and important measures of effectiveness (moe) without calculating or referring to other measures of effectiveness such as fuel consumption, performance index, emissions and operating costs. its simulation run output results include degree of saturation, uniform delay, incremental delay, control delay, intersection delay and los (see table 3). 6.2. optimization of bukhari signalized intersection using; hcs 2010, sidra 5.1 and transyt-7f release 11 software tools for the comparison and evaluation purposes of the selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 in term of their results of optimizing isolated signalized intersections signal timing. an optimization runs applied on bukhari isolated signalized intersection using the selected three softwares and the major output results of the three optimization runs of the three selected softwares are summarized in tables 6, 7 and 8. bukhari signalized intersection optimization major outputs resulted from the simulation runs of the selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 show that:  the three selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11 have optimization capabilities.  sidra 5.1 is very effective and the richest software to optimize isolated signalized intersections. its optimization of signalized intersection cycle time produce very significant improvement on the intersection measures of effectiveness. its output results include very important improved measures of effectives such as optimized cycle length, degree of saturation , total and average delay, los, performance index (disutility index), fuel consumption, emissions, and operating costs (see tables 4 and 7).  transyt-7f is very capable and effective software to optimize isolated signalized intersections. its optimization of signalized intersection cycle time produce very high percentage of improvement in the intersection measures of effectiveness. its output results include optimized cycle length, control delay, fuel consumption and performance index (disutility index) (see table 8). the optimization output results are much summarized and not reflect the optimization capabilities of transyt-7f, therefore a simulation run applied using optimized cycle and phase’s times to measure the improvement in the measures of the effectiveness for bukhari signalized intersection. the simulation run using optimized cycle and phase’s times major results include degree of saturation, uniform delay, random delay, total delay, average delay, los, performance index (disutility index) and fuel consumption which clearly explain the very big improvement in the measures of effectiveness of bukhari signalized intersection (see tables 5 and 9). al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 198 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 4. operation analysis (a simulation run) major output results for bukhari signalized intersection using sidra 5.1  hcs 2010 provides very simple and basic optimization output results with good improvement in reducing the intersection delay and enhance the intersection los. the optimization results include some major and important measures of effectiveness (moe) without calculating or referring to other measures of effectiveness such as fuel consumption, performance index, emissions and operating costs. its optimization run output results include degree of saturation, uniform delay, incremental delay, control delay, intersection delay and los (see table 6). operation analysis outputs eastbound westbound northbound southbound lt th lt th lt th lt th degree of saturation (%) 71.8 71.8 144.4 144.4 73.3 28.1 29.1 29.1 average delay (sec) 60.8 60.8 264.5 264.6 62 46.5 45.9 45.9 los e e f f e d d d approach degree of saturation (%) 71.8 144.4 73.3 29.1 approach average delay (sec) 60.8 264.5 57.4 45.9 approach level of service (los) e f e d intersection degree of saturation (%) 144.4 intersection total control delay (veh-h/h) 97.91 intersection average control delay (sec) 161.7 intersection worst lane control delay (sec) 264.6 intersection worst movement control delay (sec) 264.6 intersection geometric average delay (sec) 3 intersection stop-line average delay (sec) 161.7 intersection level of service (los) f performance index (disutility index) 260.5 total cost ($/hr) 1935.15 total fuel consumption (l/hr) 340.2 total carbon dioxide (kg/hr) 852.8 total hydrocarbons (kg/hr) 1.609 total carbon monoxide (kg/hr) 54.08 total nox (kg/hr) 1.62 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 199 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 5. operation analysis (a simulation run) major output results for bukhari signalized intersection using transyt-7f release 11 lt * : the left movement is shared with the through movement table 6. signal timing optimization major output results for bukhari signalized intersection using hcs 2010 operation analysis outputs eastbound westbound northbound southbound lt * th lt * th lt * th lt * th degree of saturation (%) 98 191 60 26 36 uniform delay (veh-h) 7.5 42.8 3 1.1 2.7 random delay (veh-h) 4.9 127.1 0.4 0 0.1 total delay (veh-h) 12.4 170 3.4 1.2 2.8 average delay (veh-h) 89 555 49 41 46 fuel consumption (liter) 73 558 27 10 23 level of service (los) f f d d d intersection degree of saturation (%) 191 intersection uniform delay (veh-h) 57.2 intersection random delay (veh-h) 132.6 intersection total delay (veh-h) 189.9 intersection average delay (veh-h) 313 intersection fuel consumption (liter) 693 intersection performance index (disutility index) 178 intersection level of service (los) f optimization outputs eastbound westbound northbound southbound lt lt lt lt lane group degree of saturation (%) 91 87 95 94 lane group uniform delay (sec) 41.3 28.4 44.3 46.4 lane group incremental delay (sec) 21 8.1 36.4 45.2 lane group control delay (sec) 62.3 36.6 80.7 91.6 lane group los e d f f approach control delay (sec) 62.3 36.6 80.7 91.6 approach los e d f f optimum cycle length (sec) 100 intersection delay (sec/veh) 55.2 intersection los e al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 200 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 7. signal timing optimization major output results for bukhari signalized intersection using sidra 5.1 optimization outputs eastbound westbound northbound southbound lt th lt th lt th lt th degree of saturation (%) 86.1 86.1 85.5 85.5 84.6 32.4 37.9 37.9 average delay (sec) 92.6 92.6 61.2 61.3 89.5 61.9 65.1 65 los f f e e f e e e approach degree of saturation (%) 86.1 85.5 84.6 37.9 approach average delay (sec) 92.6 61.3 81.4 65 approach los f e f e optimum cycle length (sec) 160 intersection degree of saturation (%) 86.1 intersection total control delay ( veh-h/h ) 43.69 intersection average control delay (sec) 72.2 intersection worst lane control delay (sec) 92.6 intersection worst movement control delay (sec) 92.6 intersection geometric average delay (sec) 3 intersection stop-line average delay (sec) 72.2 intersection los e performance index (disutility index) 186.4 total cost ($/hr) 1167.8 total fuel consumption (l/hr) 249 total carbon dioxide (kg/hr) 624 total hydrocarbons (kg/hr) 1.095 total carbon monoxide (kg/hr) 44.49 total nox (kg/hr) 1.365 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 201 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 8. signal timing optimization major output results for bukhari signalized intersection using transyt7f release 11 table 9. operation analysis (a simulation run using optimized cycle length) major output results for bukhari signalized intersection using transyt-7f release 11 lt * : the left movement is shared with the through movement optimization results eastbound westbound northbound southbound initial signal timing (sec) green=20 yellow=5 all red=2 green=25 yellow=5 all red=2 green=30 yellow=5 all red=2 green=25 yellow=5 all red=2 optimized signal timing (sec) green=27 yellow=5 all red=2 green=46 yellow=5 all red=2 green=21 yellow=5 all red=2 green=8 yellow=5 all red=2 initial cycle length (sec) 128 optimized cycle length (sec) 130 initial control delay (sec/veh) 314 optimized control delay (sec/veh) 86.9 initial fuel consumption (lit/hr) 694 optimized fuel consumption (lit/hr) 314 initial performance index (disutility index) 178.8 optimized performance index (disutility index) 71.12 operation analysis (optimized cycle time) outputs eastbound westbound northbound southbound lt * th lt * th lt * th lt * th degree of saturation (%) 74 105 87 38 113 uniform delay (veh-h) 6.7 13.6 3.7 1.4 4.3 random delay (veh-h) 0.9 13.2 1.9 0.1 6.4 total delay (veh-h) 7.7 26.8 5.6 1.5 10.7 average delay (veh-h) 55 87 80 52 177 fuel consumption (liter) 58 161 34 11 47 los e f f d f intersection degree of saturation (%) 113 intersection uniform delay (veh-h) 29.8 intersection random delay (veh-h) 22.6 intersection total delay (veh-h) 52.5 average delay (veh-h) 86 fuel consumption (liter) 314 performance index (disutility index) 71 intersection level of service (los) f al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 202 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 7. conclusions 1. based on a comparison between the operation analysis results (simulation runs) of selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11. sidra 5.1 is the most effective and the richest operation analysis software among the three selected softwares, because of its wide range of output results which included; degree of saturation, total and average delay, los, performance index (disutility index), fuel consumption, emissions, and operating costs. 2. based on a comparison between the optimization capabilities and optimization run results of selected computer traffic analysis software tools; hcs2010, sidra 5.1 and transyt-7f release 11. sidra 5.1 is the most effective and the richest optimization software among the three selected softwares, because of its large reduction of intersection delay and improving the intersection los, in addition to its wide range of output results which included; degree of saturation, total and average delay, los, performance index (disutility index), fuel consumption, emissions, and operating costs. 3. transyt-7f release 11 is very reliable and capable software in term of making a significant improvement in the measures of the effectiveness for the signalized intersections through the optimization of intersection cycle and phase’s times. 4. hcs2010 is simple and easy software for operation analysis and signal time optimization of signalized intersection especially that is targeting the evaluation of intersection delay and level of service (los) and improving them, because of its significant reduction of intersection delay and improving the intersection los, but with limited range of output results which not including performance index (disutility index), fuel consumption, emissions, and operating costs. recommendations based on the results of this research it is highly recommended that iraqi traffic engineers to select sidra 5.1 for operation analysis and optimization of signal timing of signalized intersections as it is the most effective and the richest operation analysis and optimization software among the three selected study softwares. references 1. al-omari, b., ta’amneh, m., 2007. validating hcs and sidra software for estimating delay at signalized intersections in jordan. , 1(4), pp.375–392. 2. jameel, a., 2011. estimating delay time at palestine street intersections in baghdad city using hcm and sidra models. , 4(1). 3. mctrans, 2012. hcs 2010 user’s guide, university of florida. 4. mctrans, 2008. transyt-7f user’s guide 11th ed., university of florida. 5. sidra solutions, 2012. sidra intersection user guide, akcelik & associates pty ltd. 6. washburn, s., larson, n., 2002. signalized intersection delay estimation : case study comparison of transyt-7f , synchro and hcs this feature has two. , (march). <4d6963726f736f667420576f7264202d20e3dacfe120c7d3e1e6c820cde120cccfedcf20dded20cad5e3ede320e3c8cfe120c7e1ed20d0e620cbe1c7cb20d3d1da20cee1e6cf20cdd3e420d5c7e1cd2020202037> al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 77 a solution technique for design of threespeed automatic speed changer kholood hasan salih assistant lecturer, machinery and equipment department institute of technology-baghdad, foundation of technical education baghdad, iraq email:kholood_hassan@yahoo.com abstract recently, there has been an increasing interest in the development of bicycles speed changers. multi-speed changers allow cyclists to pedal at their most efficient pace at different road conditions. in this paper, a modified solution technique based on a flawed previous one is presented to investigate the kinematics, the torque distributions and the power flow through one-degree of freedom planetary gear trains. nomographs are used as a design tool to enable the designer to simultaneously visualize these one-degree of freedom variables without first selecting a particular pgt and without the need to solve equations repeatedly. after that, these techniques will be applied to design a three-speed automatic speed changer. three design examples are demonstrated to illustrate this modified methodology. keywords: solution technique, automatic speed changer, planetary gear train, nomography, bicycle, design. لّي ذو ثالث سرعآ ةُمبّدل سرع في تصميمِ َحلٍ أسلوبُ خلود حسن صالح : مدرس مساعد معهد التكنولوجيا بغداد قسم المكائن والمعدات عراقبغداد وجزـــــالم تُتـيح المبـّدالت متعـددة . في الوقت الراهن، هناك اهتمام متزايد في تطّور مبّدالت سـرع الـدراجات الهوائيـه .لسرعه لراكبي الدراجات ان يدّوروا الدّواسات القدميه بافضل ما يمكن من سرعه في الظروف المختلفه للطريقا كينماتيكا المجموعات الترسيه الحل الحالي يتحرى لحٍل سابٍق معيب ، ُمنقحُيقّدْم هذا البحث اسلوب َحّل كمــا َيســتخدْم المخططــات النوموغرافيــه. وتــدفق القــدره خاللهــاالكوكبيــه احاديــة درجــة الحريــه وتوزيــع العــزوم فيهــا المجموعـات الترسـيه الكوكبيـه احاديـة أداة تصـميميه ُتمّكـن المصـمم مـن ان يتصـّور كـل متغيـرات ويحورها لتكـون في نفس اآلن على مخطط واحد دون ان يختار مجموعه ترسـيه كوكبيـه معينـه ابتـداًء ودون الحاجـه درجة الحريه .حل المعادالت تكراراً الى al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 78 لـّى ذو ثـالث سـرع مـع آَيستعرُض البحث، باستخدام الحل الجديد واالداة التصـميميه، تصـميم مبـّدل سـرعه . ثالث امثله تطبيقيه توضّح هذه الطريقه الجديده عملياً introduction and literature review a planetary gear train (pgt) is defined as any train in which one or more gears orbit by turning about a rotating axis just as a planet turns about the sun. for the kinematic analysis of pgt's, various approaches such as the relative velocity method [1-3], energy method [wilkinson, 1960], bond graph method [allen, 1979] and the vector-loop method [gibson and kramer, 1984] and [willis, 1982] have been proposed. [freudenstein and yang, 1972] introduced the concept of fundamental circuit to analyze pgt's. the concept was further extended by other researchers [910]. the analysis involves the solution of a set of linear equations for all the kinematic variables. it does not provide much insight into mechanics of a pgt. the elementary pgt is shown in figure 1, with its simplified representation. it consists of two gears, the central (1) and planet (2) gears and the planet carrier (3) or arm .the central gear may be either an external or an internal gear. the elementary pgt is somewhat limited in practical application .more useful , however , are the pgt's referred to as the simple , compound and complex pgt's where a second central gear is used and also there is a sequence of planets ,connected in by either a shaft or by a tooth mesh , between the first and last central gears . the simple pgt shown in figure 2 consists of a first central gear (f), a planet gear (p), a planet carrier or arm (a), and a last central gear (l). [lévai, 1966] identifies twelve possible variations of pgt's; they are shown in figure 3 using kinematical representation. these pgt's are classified to (1) simple and compound pgt's in which the planet gears are in mesh with both central gears, and (2) complex pgt's in which the planet gears are partially in mesh with each other and partially in mesh with the two central gears. notice that, for these pgt's and regardless of arrangement the multiple planets are always on a common carrier (multiple central gears pgt or multiple carriers pgt will be referred to as a multistage pgt's). taking the arm to be fixed, one can quickly deduce by examination that the pgt's in quadrant (1) and (2) yield negative transmission ratios between the first and last gears while pgt's in quadrant (3) and (4) yield positive transmission ratios. [willis, 1870] discusses for the first time in published literature the analytical modeling of a pgt. he suggests the use of a generic "transmission ratio" in defining the kinematic motion of a pgt. this ratio, r, is defined as the angular velocity ratio between the last and first central gears in the train relative to the arm. mathematically, this can be written af al r ωω ωω − − = (1) graphically, this equation can be solved using nomography. nomograph is defined as three or more axes, or scales, arranged such that problems of three or more variables can be solved using a straightedge [corey, 2003]. in the particular case of egts, a nomograph can be constructed using three vertical parallel axes [2, 17] or three or more vertical parallel axes [esmail, 2007]. corey's approach [corey, 2003] is a practical one which uses nomographs to investigate both the angular velocities and the torques acting on the first, last gears and the carrier of a two input train without reaction link. however, two input planetary gear trains contain an uncertainty in the torque solution space [esmail and hassan, 2010]. unfortunately, corey applied his approach wrongly to two input epicyclic gear trains without reaction link. in my opinion and since there is no torque uncertainty in the torque solution space of epicyclic gear trains with a reaction link, therefore, corey's approach can be considered correct for such trains and in this paper it will be al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 79 adopted for one-degree of freedom epicyclic gear trains. this is the main modification to corey's approach to make it applicable to epicyclic gear trains. they origins of nomographs date back to professor maurice d'ocagne in late ninetieth century. in the particular case of epicyclic gear trains, nomographs are still under progress and not yet a well-established technique. this technique was first applied by toyota to investigate their toyota hybrid system [17]. toyota's solution is not a general, concise solution technique; it is only an application to their case, no details are given as to how nomographs can be drawn and where axes can be placed. toyota uses the three parallel axes nomograph in a different manner to that used by corey. in this paper a modified solution technique based on a previous one is developed to solve pgt's problems with the help of nomographs. pgt's are considered adaptable to suit automatic internal speed changers for bicycles. a bicycle, or bike, is a pedal-driven land vehicle with two wheels arranged in line. first introduced in 19th century, it evolved quickly into its current design. with over one billion in the world today, bicycles provide the principal means of transportation in many regions and a popular form of recreation in others. recently, there has been an increasing interest in the development of bicycles speed changers and their shifting mechanisms [13]. multi-speed changers allow cyclists to pedal at their most efficient pace at different road conditions. the bicycle will gradually adopt the automatic shifting fashion, by following the path of a motorcycle or an automobile. by referring to such related patents such as those on automatic bicycle transmission [8, 15 and 16], we form the following ideas about the bicycle speed changers: the bicycle speed changers can be divided into external and internal speed changers. the external speed changers in turn are divided into front external speed changers and back external speed changers. a complete speed changer contains: (1) the speed changer entity which is the main body of the speed changer in of transmitting the power while the bicycle is running. the chain-driven external speed changer entity consists of three parts, i.e. front chain wheel group, chain, and back chain wheel group. (2) the shifting control device which is used in controlling the operation of each gear position of bicycle speed changer entity, and is not responsible for transmitting the driving power. it is usually located inside or nearby the speed changer entity. the chain-driven external speed changer contains the front chain-shifting mechanism and back chain-shifting mechanism. the internal speed changer contains the control mechanism inside the axle and it may be (a) revolving (b) translating or (c) revolving plus translating control mechanism. (3) the shifting steer device is used to steer the shifting control device. it does not transmit power and is usually installed in a position far away from the speed changer entity. the shifting control device can use the shifting line or other means to connect with the shifting control device. most bicycle external speed changers use the parallel four-bar linkage as the main body for shifting while internal speed changers use planetary gear train (pgt) as the main body for shifting. internal speed changers use the sun gear as the controlling element to obtain the shifting effect. the shifting effect is obtained by either turning the sun gear around the central axis or by pulling or pushing the central axis. as to the external and internal speed changers, there are two shifting types; manual and electronic. manual shifting includes the shifting line and revolving handle. electronic shifting uses central process unit (cpu) with speed and torque sensors to control the shifting control device. new approaches are needed to evolve mechanical or electromechanical solutions. the prior-art inaction to evolve a widely acceptable automatic bicycle is also regrettable from environmental and socio-economic points of view, since bicycles cost much less and take much less space than automobiles, put less a load on the road, do not pollute the atmosphere like automobiles, are much less expensive to operate, and subject rider to continual salubrious exercise unavailable in any automobile. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 80 the modified planetary gear train solution technique 1nomographs for pgt's nomograph is defined as three or more axes, or scales, arranged such that problems of three or more variables can be solved a straightedge. in the particular case of pgt's, a nomograph can be constructed using three vertical parallel axes. the ωl axis is chosen to pass at the origin; also the ωl and ωf axes are chosen to be one unit [2]. following the technique developed by corey {2] with the present modifications, any straight line through arbitrary points on the ωl and ωf axes will intersect the horizontal axis, which connect the zeros of the three axes at point s, a distance s from the origin. from figure 4, we can write 1 s ww w fl l = − (2) the location of the ωa axis, for a particular pgt, is at a distance e from the origin. the ωa axis may actually be to the left of the ωl axis or between the ωl and the ωf axes or to the right of the ωf axis. in general, from figure 4, we can write fl al ww ww e − − = e can be defined in terms of r, the general transmission ratio of the gear train. also, from figure 4 e e ww ww fa al − = − − 1 (3) re-arranging, we get 1− = − − e e ww ww af al (4) which is exactly equation (1) when 1− = e e r (5) in general, e can be written in terms of r as 1− = r r e (6) for the purpose of analysis r can be found using the knowledge of the arrangement of the particular pgt with the arm fixed, so fo lo w w r = (7) now this ratio r (and hence e) is a constant, regardless of the rotational speeds of the three elements of the particular pgt, and is proportional to the tooth numbers whether the arm is rotating or not, and in general we may write teeth teeth gear gear last first of of oduct oduct r pr pr = (8) equation (8) is based on our arbitrary designation of first and last gear teeth (which is often referred to as "product of driving or driven gear teeth "). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 81 the sign of r is positive if the arbitrary designated first and last gears would rotate in the same direction with the arm stationary. in design, e can be selected arbitrary as any value other than one or zero. 2. modified solution technique for pgt's using nomographs using the principle of energy conservation, the energy balance equation for the general pgt can be written as 0=++ llffaa wtwtwt (9) figure 5 shows the torques tl, tf and ta represented as arrows perpendicular to the three axes at the points representing the rotational speeds. the moment of any torque vector about the zero of its rotational speed axis, represent the power flowing in that branch (t · ω). in general, from figure 5, we can write s w s w es w lfa = − = − 1 (10) from which al w es s w ⋅ − = (11) and af w es s w ⋅ − − = 1 (12) substituting equations (11) and (12) into equation (9), and multiplying by (s – e), we get 0)()1()( =+−+− ststest lfa (13) perhaps it is more convenient to represent the torque vectors as arrows along the three axes as shown in figure 6. therefore, equation (13) is equivalent to summing moments of the torque vectors about point s. upward torque vector is assumed to have positive sign. power flowing in the system is assumed to have positive sign also. therefore, any torque vector pointing away from zero is representative of power flow in the system. although, the s-value is a variable quantity, which depends on the operating rotational speeds of the pgt, it allows early in the design process, to visualize how the pgt is intended to react to typical pgt rotational speeds. the s-value variation with different input speeds has the distinct advantage of providing a clear visual representation of both the torque response of the pgt and the power flow through it. 3. nomographs for one-degree of freedom pgt's a pgt has three members that can serve as either inputs or outputs; the first central gear, the last central gear and the planet(s) carrier or arm. if we lock one of the three elements of the pgt and prevent it from rotation, then we have two members that can transmit power to or from the external environment; one input and one output .in this case, since the power does not branch or meet, it follows that the input power is transmitted through every link of the pgt. the planets are considered as non-torque carrying links. it is well known that under static equilibrium, torques acting on the three elements of the one-degree of freedom pgt must be summed up to zero 0=++ fla ttt (14) solving equations (9) and (14) yields lf trt ⋅−= (15) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 82 and la trt ⋅−= )1( (16) equations (15) and (16) express two of the external torques in terms of the third. figure 7 shows a nomograph for a pgt like the one shown in figure 3 (d) when the first central gear is held stationary ( s = 1 ) . by summing the torques in the y-direction, equation (14) will be obtained. equations (9) and (14) together imply that the torque vectors on the two extremes of a onedegree of freedom nomograph, both must point upward or downward and that the third torque vector must point to the opposite direction. after some examination, one finds that the torques shown in figure 7 can be solved for in the same way as forces on a rigid beam may be solved for. summing torque vectors moments about the zero of the ωa axis yields 0)1(. =−⋅+− etet fl (17) solving for tf and simplifying one arrives at equation (15). summing torque vectors moments about the zero of the ωf axis generates the equation 01)1( =⋅−−⋅ la tet (18) substituting equation (6) into equation (18), then solving for ta and simplifying, one arrives at equation (16) which is the same as equation (9) when ωf = 0. summing torque vectors moments about the ωl axis yields 0=⋅− ett af (19) similar results can be obtained when the last central gear is fixed (s = 0) or the planet(s) carrier or arm is fixed (s = e). a nomograph for a one-degree of freedom pgt's (one of the three branches is fixed), allows designer to (a)define the kinematic relationships between the three branches of the pgt without first selecting a physical arrangement of gears. (b)yield equations completely defining the torques on the three branches of the pgt. (c)yield the energy balance equation for the pgt and provide a clear representation of the power flow through it. design of automatic speed changer pgt's are considered adaptable to suit automatic internal speed changers. what follows is the design of such a gear train using the present new methodology with the help of nomographs. the first step in the design process is to set fourth any design constraints on the design. 1. design constraints in this paper, several requirements must be met for the design to be viable. these are: 1. the input and output speeds of the speed changer must rotate in the same direction. 2. the speed changer needs to possess three output speeds. they are in the rang of ±30 to ±40 % of the ideal pedaling speed (cadence) usually associated with efficient riding. 3. the speed changer needs also to possess the automatic shift function that replaces the manual or the electromechanical fashions. 4. the foot-board axle is connected with the shift mechanism's input axle. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 83 5. considering the effect of the output axle, the characteristic of one-way clutch is that the fast oneway clutch acts as the output. considering the effect of the input axle, the slow one-way clutch acts as the input. 2. design of three-speed automatic changer in what follows one-way clutches and centrifugal clutches are reviewed a one-way clutch (owc) consists of an inner ring with a slanting flange, an outer ring and several rollers placed between the inner ring and the outer ring. if the one-way clutch inner ring is the driving part, the outer ring is the driven part. when the inner ring rotation speed is larger than that of the outer ring, the rollers will move to the high end of the slanting flange of the inner ring, thus causing the inner ring, outer ring and rollers of the one-way clutch to join together in one part and move as a rigid body. by this movement, the one-way clutch transfers the driving power from the inner ring (driving part) to the outer ring (driven part). when the inner ring rotation speed is lower than that of the outer ring or has stopped, the rollers will move to the lower end of the slanting flange of the inner ring, thus causing the inner ring and outer ring to separate .the outer ring can now rotate freely in the same direction (or make circular movements. in this paper, figure 8(a) shows the one-way clutch in the separated state, while figure 8(b) shows the one-way clutch in the engaged state. a centrifugal clutch consists of clutch crust, clutch blocks and clutch springs. the input axle and output axle are respectively connected with clutch blocks and clutch crust. the driving power is transferred to the driven axle by the centrifugal force caused by the clutch rotation. in this paper, figure 8(c) shows the centrifugal clutch in the separated state whereas figure 8(d) shows the centrifugal clutch in the engaged state. pgt's combined with one-way clutches and centrifugal clutches, have led to the design of the automatic internal speed changer as shown in figure 9. to make the design of the system simpler, nomographs are used to quickly and simply remove ranges of r from consideration. referring to the nomograph in figure10, the graph can be divided into three sections labeled in the figure. the sections represent the locations of the ωa axis for the cases of r listed in the figure. for example, if r=-0.5, e=⅓ from equation (6) and the ωa axis must lie between the ωl and ωf axes. this nomograph gives the designer the ability to quickly select a broad range for r, depending on how the gear train is intended to react to typical input speeds. nomographs, like the one in figure 7 in which the first central gear is fixed, ωf =0, allow the designers to visualize critical details of a design's response. the designer can freely select one torque and either the two remaining speeds or one rotational speed and the general transmission ratio; r. nomographs provide some insight into the fundamental differences between these two approaches. in the first approach, one can visualize drawing a straight line between the selected speeds on the ωf and ωl axes and placing the ωa axis such that it intersects this line at the selected rotational speed at the arm. in the latter approach, the designer would simply place the ωa axis according to equation (6), draw a straight line between the two selected speeds, and read on the third axis the unspecified speed. to search for an appropriate r, one can examine the first design constraint that the input and output speeds of the speed changer must have the same sign. figure 11 shows three nomographs for the system for the three ranges of r. notice that when r is between negative infinity and zero and between zero and one, the rotational speeds ωl and ωa both have the same sign. conversely when r is between one and infinity, the rotational speeds ωl and ωa have opposite signs. with this range of r-values eliminated, the ranges that need to be considered during the design effort from here forward are (a) between negative infinity and zero and (b) between zero and one. pgt's with r-values between one and infinity can have r-values between zero and one if the arbitrary designation of first and last gears is replaced by each other. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 84 after establishing broad ranges of r-values to be considered, the next task is to attempt to apply the remaining design constraints to the governing equations of the system. examining the second design constraint, using equation (9) and putting ωf =0, we get, ta ωa + tl ωl = 0. it is convenient to rewrite this equation in the form a l l a t t ω ω −= (20) since the three output speeds of the speed changer are in the range of ±30 to ±40 % of the ideal pedaling speed as required by the second design constraint, and the input and output torques are inversely proportional to these speeds, as seen from equation (20), then the design will allow cyclist to pedal it his ideal cadence at different road conditions. the gear needed will depend on the slope of the road, the wind conditions and the cyclist own condition at any given time. aside from selection of a broad range for r, the nomograph also has the distinct advantage of providing a clear visual representation of both the torque response of the gear train and the power flow through the pgt. returning to figure 7, one can visualize speeds, torques and power flow through the pgt from a single nomograph. since the human body provides most efficient power between speed of 80 and 100 rpm, it would be advantageous to select a gear ratio that would place the values of ωl and ωa in the range of ±30 to ±40 % of this speed. obviously, as shown in figure 11, a designer could select e between 0.21 to 0.29 ( r = 0.23 to 0.28 ) or between ─ 0.39 to ─ 0.3 ( r = ─ 0.4 to ─ 0.27 ) with a nominal cadence to force both speeds into the ideal region. nomographs allow engineers to define the above values and the relationships between the three branches of pgt without first selecting a physical arrangement of gears . as can be seen from figure 12, the value of ωa asymptotically approaches zero, while ωl increases linearly with decreasing r. the same results can be obtained from figures 12 and 13 as those obtained from figure 11. figure 13 shows the output rotational speeds in terms of the basic transmission ratio r for nominal cadence. ,shown on the nomographs of figure 11. after selecting a gear ratio, it becomes important to decide upon one of the twelve possible arrangements of the gear trains. returning to figure 3, taking the arm to be fixed, one can quickly deduce by examination that the trains in quadrants (1) and (2) yield negative ratios between the first and last central gears while those in quadrants (3) and (4) yield positive ratios. in order to simplify the actual construction of the device, only the simple trains in figure 3 will be considered. 3. design of three-speed automatic speed changer of bicycle by applying the above solution technique three types of three-speed automatic changers are created. 3.1 plan 1 this design adopts the pgt shown in figure 3(d) to achieve the front internal speed changer shown in figure 14. as required by the fourth design constraint, the foot board rotation axle is used as the input axle of the automatic speed changer. the actuating maps of the three speeds of this plan are shown in figure 15 (a), (b) and (c) with their corresponding nomographs. at the beginning, the one-way clutch owc-l, and one-way clutch owc-a are engaged. the driving power is transmitted to the chain device via the last gear (ring gear), planet gear and arm of the pgt. when the speed reaches a preset level, the clutch c-l engages and the one-way clutch owc-a separates. the driving power is then transmitted directly to the chain device. if the engine speed is increased again, the clutch c-a engages and the one-way clutch owc-l separates. the al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 85 driving power is transmitted to the chain device via the arm, planet gear and the last gear of the pgt. 3.2 plan 2 and 3 these designs adopt another pgt's with positive train ratios to achieve the automatic three-speed front internal speed changers. design 2 is shown in figure 16. the actuating maps of the three speeds of this design are shown in figures 17 (a), (b) and (c) with their corresponding nomographs. nomographs are plotted for r=0.25 (e=-⅓) and 80 rpm cadence. design 3 is shown in figure 18. the actuating maps of the three speeds of this design are shown in figures 19 (a), (b) and (c). since r=0.25 (e=-⅓) for this train which is the same as that for pgt of design 2, nomographs are the same for both of these trains and will not be repeated. conclutions this study contributes to the development of a solution technique for the analysis of the kinematics, the torque distributions and the power flow through one-degree of freedom pgt's. nomographs are used as a design tool to enable the designer to simultaneously visualize these variables without first selecting a particular pgt and without the need to solve equations repeatedly. after developing the solution technique and the design tool, these were applied to design a threespeed automatic speed changer. pgt's are considered adaptable to suit automatic internal speed changers. pgt's combined with one-way clutches and centrifugal clutches, have led to the design of the automatic bicycle speed changer. three design examples were demonstrated to illustrate the methodology. the design can serve as a reference to industrial circles to develop three-speed automatic speed changers bicycles. references [1]allen, r. r., "multi-port models of the kinematic and dynamic analysis of gear power transmission", asme j. of mechanical design, volume 101, pp. 258-392, 1979. [2]corey, c. a.,"epicyclic gear train solution technique with application to tandem bicycling", thesis (m. sc.), department of mechanical engineering, virginia polytechnic institute and state university, blacksburg, va,usa., 2003. [3]esmail, e. l., "kinematic nomographs of epicyclic-type transmission mechanisms", emirates journal for engineering research, 12(3), pp.47-55, 2007. [4]esmail, e.l. and hassan, s.s., 2010, "an approach to power-flow and static force analysis in multi-input multi-output epicyclic-type transmission trains," asme j. of mechanical design, 132. [5]freudenstein, f., and yang , a. t. , "kinamatics and statics of coupled epicyclic spur gear trains", j. of mechanism and machine theory , volume 7, pp. 263-275, 1972. [6]glover, j. h., "planetary gear systems", product engineering, sept., pp. 72-79, 1965. [7]gibson, d. and kramer, s. "symbolic notation and kinamatic equations of motion of the twenty-two basic spur planetary gear trains", asme j. of mechanisms, transmissions and automation in design, volume 106, pp. 333-340, 1984. [8]grant, f. f. , " automatic transmission systems for humanly powered vehicles", u. s. patent, no. 6354980, 2002. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 86 [9]hsieh, h. i. ,"enumeration and selection of clutching sequences associated with epicyclictype transmission mechanisms", ph.d. thesis, department of mechanical engineering, university of maryland at college park, maryland, usa,1996. [10]http : // www.mech.uwa.edu.au/danotes/gears/epicyclic.html#top. notes on design and analysis of machine elements . wright , d., 2005. [11]levai ,z., "theory of epicyclic gears and epicyclic change-speed gears", doctoral dissertation, budapest, 1966. [12]levai, z., "structure and analysis of planetary gear trains", journal of mechanisms, volume 3, pp. 131-148, 1968. [13]long-chang hsieh and tzu-hsia chen, "the systematic design of automatic three-speed gear hub for bicycles", proceedings of the international multi conference of engineers and computer scientists 2008 vol ii imecs 2008, 19-21 march, 2008, hong kong. [14]pennestri, e. , and freudenstein, f. , "a systematic approach to power-flow and static force analysis in epicyclic spur-gear trains", asme j. of mechanical design, volume 115, no. 3 , pp. 639-644, 1993. [15]spence, m. d. , "automatic bicycle transmission", u. s. patent, no. 3995508, 2000. [16]tabe, k. , ""automatic bicycle hub transmission using flyweights", u. s. patent, no. 6010425,2000. [17]toyota motor corporation, http://www.autoshop101.com/forms/hybrid02.pdf [18]wilkinson, w. h., "four ways to calculate planetary gear trains", machine design, january 7, pp. 155-159, 1960. [19]willis, r. j.,"on the kinamatic of the closed epicyclic differentioal gears", asme j. of mechanical design, volume 104, pp. 712-723, 1982. [20]willis, r., "principle of mechanism", second edition . longmans, green co., london, 1870. [21]william, j., "automatic bicycle transmission", u. s. patent, no. 5199929, 1993. (a) (b) figure 1 (a) the elementary pgt and (b) its kinematical representation. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 87 figure 2 pgt of the lower arrangement. figure 3 the simple, compound and complex pgt's as originally presented by lévai. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 88 figure 4 general layout of a nomograph for a pgt. figure 5 nomograph with torques represented as vectors perpendicular to the rotational speeds axes. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 89 figure 6 nomograph with torques represented as vectors along the three axes. figure 7 nomograph for the pgt. (a) separated state (b) engaged state one-way clutch (c) separated state (d) engaged state centrifugal clutch figure 8 one-way clutch and centrifugal clutch in the engaged and separated states. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 90 figure 9 the automatic internal speed changer design. figure 10 nomograph with ranges of basic transmission ratio r labeled. figure 11 nomographs for the system for the three ranges of r with ideal regions. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 91 figure 12 output rotational speeds ωa and ωl as a function of train ratio r, for two pedaling speeds 80 and 100 rpm figure 13 ideal regions for the basic transmission ratio r al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 92 figure 14 design 1 for the bicycle three-speed automatic changer. (a) first speed (b) second speed (c) third speed figure 15 the three speeds of the speed changer of plan 1. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 93 figure 16 design 2 for the bicycle three-speed automatic changer. (a) first speed (b) second speed (c) third speed figure 17 the three speeds of the speed changer of plan 2. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 94 figure 18 design 3 for the bicycle three-speed automatic changer. (a) first speed (b) second speed (c) third speed figure 19 the three speeds of the speed changer of plan 3. the effect of neighboring of earth cable to the power cables at the operation of earth fault protection unit al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٧ the effect of proximity of earthing cable and power cables on the operation of earth fault protection unit and cathodic protection daud. m. jasim electrical power department/ al-musayab –tech.-college abstract this work discusses the effect of proximity between the grounding cable and power cables of high hp 3-ph induction motor, on the operation of the unit of protection against earth fault current and on the system of cathodic protection of the pipes in deep wells, due to high circulating current of grounded cable, induced by the magnetic flux of a 3-ph current of induction motor because of the proximity effect. the work contains practical beneficial experiments, in the work site, for measuring circulating currents, theoretical analysis, useful conclusions and a very useful recommendation to the engineers deal with this field. it is shown that the reason of circulating current in the earthing cable and the cathodic protection cable is the neighboring of earthing cable to the power cables. keywords: proximity effect, grounding cable, earth fault current, cathodic protection, magnetic flux الحمایة ضد الخطأ االرضي تأثیر تقارب الموصل االرضي وموصالت القدرة على عمل وحدة والحمایة الكاثودیة سم داود مشیر جا الكلیة التقنیة المسیب-قسم الكهرباء الملخص الثالثیـة االطـوار ذات المحركـات الحثیـةيان هذا العمل یتطرق الـى تـاثیر التقـارب بـین الموصـل االرضـى وموصـالت القـدرة فـ الحصانیة العالیة علـى عمـل منظومـة الحمایـة ضـد التوصـیل االرضـي وعلـى عمـل منظومـة الحمایـة الكاثودیـة النابیـب االبـار القدرة ریض بسـبب الفـیض المغناطیسـى المتولـد مـن التیـار المـار فـى موصـالت التغذیـة أالعمیقة نتیجة التیار الدوار المتولـد فـى موصـل التـ وتحلـــیالت نظریـــة لقیـــاس التیـــارات الـــدوارةلبحـــث تجـــارب عملیـــة مجدیـــة فـــي حقـــل العمـــلایتضـــمن. المســـایرة للموصـــل االرضـــي واثبــت بــأن ســبب التیــار الــدوار فــي موصــل التــأریض وفــي .مفیــدة جــدا للمهندســین العــاملین فــي هــذا المجــالوتوصــیاتواســتنتاجات .هو مجاورة موصل التأریض الى موصالت القدرةموصل الحمایة الكاثودیة introduction high power 3-ph induction motors, which are used in deep wells, get a power via long cables. the 3-ph current passing through the cables for high hp induction motors which are used in a deep well creates a changing magnetic field, which induces a current in other near by al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٨ conductors,(http://en.). this phenomena has a negative effect on the operation of the circuit breaker with earth fault relay which will be tripped when the motor put on line (black et al; http://electrical 2009). also it has a negative effect on the operation of the cathodic protection (peabody, 2000; morgan, 1987). several efforts were done by local engineers to know the reasons, and after very hard inspections they decided to consider that the motor earth cable connection is redundant as it creates a return path for undesirable induced current, with unknown reasons (thwaites, 1997 ). in this work several tests of inspections were done on a well pump motor of 250 hp with a depth of about 150 m, at which the problem of the earth protection failure had been happened, comparing the results with a theoretical analysis results, thus identifying the reason. region of analysis and grounding circuit of the original system: the region of analysis is shown in (fig. 1) the values of resistances are measured between the above equipment and the copper ground grid at well head pcu substation. and are as follow : r1=0.527ω resistance motor casing / ground r2=0.64ω gland plate (column pipe)/ground resistance r3=0.12ω gland plate / motor casing resistance r4=0.51ω well casing (cathodic protection cable / ground practical part testing of circulating current test (1): all grounds isolated (i1 = i2 = i3 = 0a), fig. (2) test (2): motor casing grounded, (fig. 3): the values of circulating currents are : i1 = 4.7a , i2 = 0 a , i3 = 0 a test (3): (a) motor casing grounded (b) gland plate grounded, fig. 4 the values of the circulating currents are: (i1 = 52.2 a , i2 = 47.5 a, i3= 0 a) test (4): motor casing grounded, gland plate grounded and cathodic protection cable grounded. fig. (5) the values of the circulating currents are : (i1=58 a, i2=47.5 a and i3=10.2 a). test (5): motor casin g grounded and cathodic protection cable grounded, fig. (6) the values of the circulating currents are: (i1=9.6 a, i2=0 a, i3=9.5 a) test (6): motor casing grounded and gland plate connected to cathodic protection cable, both isolated from ground, fig. (7) the values of the circulating currents are: (i1=8a, i2=6a and i3=6 a). test (7): motor casing connected to gland plate both isolated from ground, fig. (8) the circulating current is : (i1=47.5a). test (8): motor casing grounded, gland plate grounded and motor casing connected to gland plate, fig. (9) the circulating currents are: (i1: 21 a, i2: 16 a and i between casing cable point and grand plate equal 31 a). http://en http://electrical al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٩ test (9): gland plate grounded and cathodic protection cable grounded, fig. (10) the circulating currents are: (i1=0, i2= trace and i3=trace) the installation:referring to fig.1 of the original system we have, from the test data following results: the test data awhen a, b, c non grounded (voltage w.r.t earth at a=0.25v, b=5v). bwhen only b grounded and a, c not grounded (voltage w.r.t earth of a =5v and current through b =4.7a . cboth a and b grounded, c not grounded (current through a =47.5a, b=52.5a). dall a, b and c grounded (current through a=47.5a, b=57.2a, c=10.2a). eresistance to earth of a ≈ 0.6 ω. fresistance to earth of b ≈ 0.5 ω. gresistance between a and b = 0.1 ω. analysis as the power supply cable to pump motor is 3-ph single core, its flux will link with the pipe column and the grounding conductor thus induces an e.m.f in it. the magnitude of this e.m.f is depending on the relative location of pipe column and grounding conductor w.r.t power supply cables.the instantaneous polarity of the voltage at a and b will the same. i.e there will be a phase different of 180° between a and b voltage vectors . the phase angle between the voltage will depend upon the resistance and inductance (self and mutual) of the conductor a and pipe column. we can simplify the installation in the following circuit, (fig. 13) from test result as ea=0.25v, eb=5v. rc: resistance of water column =0.5ω (measured as resistance to earth at b with c grounded ) rg: resistance between a and b =0.1ω (difference between e and f of test data ) . rg: ground resistance . the electrical circuits analysis of tests : test(2): with b and e shorted, i.e b grounded the potential of point o will rise to 5v, applying loop theory (b.l. theraja 1979; william h. hayt 2009). the current flowing through b is 5a. this will result in a potential rise of 5.25v of point a w.r.t ground. this is illustrated in the circuit shown in, (fig. 14): i1 * 1 = 5 hence i1 = 5a (1) test (3): with both a and b grounded, the current through b is 52.5a and that through a is 47.5a. the current passes through water column is 5a. (fig. 15) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٠ (i1-i2) ×1=5 (2) (i1-i2) ×1-0.1×i2=0.25 (3) hence i1=52.5, i2=47.5 test (4): with both a, b and c grounded the current through b is 57.5a and that through a is 47.5a and that through c is 10a. (fig. 16) (i1-i2)×0.5=5 (4) (i1-i2) ×0.5-0.1×i2=0.25 (5) hence i1=57.5, i2=47.5 test (5): with b grounded, c (cathodic protection cable) grounded the current through b is 10a and that through c is 10a also, (fig. 17) i1 × 0.5 = 5 (6) hence i1 = 10 , i2 = 0 (a not grounded) test (6): with b grounded, a connected to c (both isolated from ground) the current through b is 8.2 a and that through a and c is 6.4 a (fig. 18) (i1-i2)×0.5+i1×0.5=5 (7) (i1-i2)×0.5-i2×0.1=0.25 (8) hence i1=8.2, i2=6.4 test (7): with b connected to a and b, both isolated from ground the current through b is 47.5, (fig. 19) i1×0.1+0.25=5 (9) hence i1=47.5 test (8): with b and a grounded, motor casing connected to gland plate the current equations are: (i1-i2)×1=5 (10) hence i1-i2=5 (i+i2) ×0.1+0.25=(i1-i2) ×1 (11) (i+i2) ×0.1+0.25=5 (12) hence i+i2=47.5 and i+i1=52.5 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠١ if i=31a and i1=21a and i2=16a (from test 8) then i+i1=52a which is in a good agreement with the theoretical value and i+i2=47a which is also in a good agreement with theoretical value. i1-i2=5a it is the current passing through earth resistance. test (9): gland plate grounded, cathodic protection cable grounded ,the current through b,i1=0, through a=trace, through c=trace, (fig. 21) 0.25-(0.1+0.5)× i2=0 (13) hence i2=0.4 a comparison between measuring and theoretical results the comparison between measuring and theoretical results are shown in table (1). the results discussion the results of the test (2) to test (8) and the theoretical results are nearly identical and indicate that there are a circulating currents in the earthing system which lead us to conclude that there is a problem with the motor windings, while test (9) indicates that the system is operating normally (with the fact that there is no any problem in the motor windings which means that there must not be any circulating current in the earthing cable even if it is joined to the earth that means there is another reason to this circulating current. this reason is the induced undesirable current in the earthing cable due to the proximity of it with the power cable (http://en), which lead to tripping of circuit breaker by earth fault relay (http:// electrical 2009), so this earthing must be cut off but in this case the diagnoses of winding failure during the operation will be impossible and will lead to a major problem. the results show us also that this circulating current has a direct effect on operation of a cathodic protection because this current is considered as a stray current and is free to enter an underground steel structure, corrosion can occur at the point current discharge. in severe cases, the corrosion rate can be catastrophic (peabody 2000). conclusion and recommendation in spite of the small resistance between motor casing and ground (fluid resistance and well pipe to earth resistance).the motor casing must be joined to earth for several reasons: one is that if a leakage current of a small value passes from motor windings, this cannot be sensed with out earthing cable, and this can lead a very dangerous default in the motor winding. second, any leakage current will have a serious problem to the cathodic protection system, which must have a constant current to protect the pipes (peabody 2000). we saw from the tests that the reason of circulating current is not a failure in motor windings but the induced undesirable current in the earthing cable which is caused as a result of proximity of this cable with the power cables for this reason we recommend that the earthing cable must be joined separately and a way from power cables as far as possible. http://en al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٢ references a.w peabody, control of pipe line corrosion, national association of corrosion engineers, houston 2000. b. l. theraja, " a text-book of electrical technology, 1979" black burn and j. lewis " protective relaying principles and applications , 1982, "chapter 11". http://en .wikipedia.org/wiki/proximity effect (electromagnetism). http://electrical and electronics. org//wp. content/ uploads/2009/ 03/ over-current-and-earth-. morgan, j. h. " cathodic protection " national association of corrosion engineers (nace) 2nd edition 1987. thwaites, t. j., " circulating current" great man-made river project, phase i sarir wellfield, bengazi, may 1997. william h. hayt and steven m. dutbin " engineering circuit analysis, eight edition 2009. table (1) , the measuring and theoretical results measuring results theoretical results test (2) i1=4.7a, i2=0, i3=0 i1=5a, i2=0, i3=0 test(3) i1=52.2, i2=47.5, i3=0 i1=52.5, i2=47.5, i3=0 test(4) i1=57.2, i2=47.4, i3=9.6 i1=57.5, i2=47.5, i3=0 test(5) i1=9.6, i2=0, i3=9.5 i1=10, i2=0,i3=10 test(6) i1=8, i2=i3=6 i1=8.2, i2=i3=6.4 test(7) i1=47.5, i3=i2=0 i1=47.5, i3=i2=0 test(8) i1=21a, i2=16a i the current between motor casing cable and gland plate=31a,the current through motor casing cable 52.2a i+i2=47.5a, i1-i2=5, i+i1=52.5 test(9) i1=0, i2=trace, i3=trace i1=0, i2=0.4, i3=0.4 http://en http://electrical al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٣ fig. (1), the grounding cct of the original system fig. (2), the grounding cct of test (1) r 3= 0. 12 r1=0.52ω r2=0.64ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable r 4= 0. 12 ω r1=0.52 r2=0.64ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable i1=0 i2=0 i3=0 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٤ fig. (3), the grounding cct of test (2) fig. (4), the grounding cct of test (3) r 3= 0. 12 ω r2=0.64ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable i1=4.7a i2=0 i3=0 r 3= 0. 12 ω r4=0.51 ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable i1=52.2 i3=0 i2=47.52 a al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٥ fig. (5), the grounding cct of test (4) r 1 = 0 . 6 4 7 ω r2=0.59ωhot measured r 3= 0. 12 r4=0.58ω motor casing connection cable ga sk et gland plate motor casing well pipe cathodic protection cable column pipe r 3= 0. 12 ω r2=0.64 ω r4=0.58ω motor casing connection cable ga sk et gland plate motor casing well pipe cathodic protection cable i1=48a i3=4a i2=42a column pipe i1=9.6 i3 i3 i2=0 jb2 r4=0.51 ω i1 i2 i3 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٦ fig. (6), the grounding cct of test (5) fig. (7), the grounding cct of test (6) fig. (8), the grounding cct of test (7) r 3= 0. 12 ω r1=0.52 ω r2=0.64 ω r4=0.58ω motor casing connection cable ga sk et motor casing well pipe cathodic protection cable column pipe jb2 i1=47.5 i3=0 r4=0.51 ω r 3= 0. 12 ω r2=0.64 ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing cathodic protection cable i1=8a i3 i2=6 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٧ fig. (9), the grounding cct of test (8) fig. (10), the grounding cct of test (9) r1=0.52 ω motor casing connection cable column pipe gland plate motor casing well pipe cathodic protection cable i1=0 i2=t i3=t r 3= 0. 12 ω r4=0.58ω motor casing connection cable ga sk et motor casing well pipe cathodic protection cable column pipe 21a 31a r4=0.51 ω 52.2a 16 a i3=0 r4=0.51ω al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٨ fig. (11), the original system a) b) fig. (12), the flux lines and the polarity of induced voltages fig. (13), the simplifying analytic cct of the original system a b c e rg=0.5 ω ba ee + o c 0.1 ω rc=0.5ω rg=0.5ω a a b b + + o al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٩ fig. (14) the corresponding electrical cct of test (2) fig. (15) the corresponding electrical cct of test (3) fig. (16) the corresponding electrical cct of test (4) fig. (17) the corresponding electrical cct of test (5) + o c 0.1 ω rc=0.5ω rg=0.5ω + 5v ba ee i2 i1 + o c 0.1 ω 0.5ω + 0.25v 5v ba ee i2 i1 + o c 0.1 ω 0.5ω + ba ee i2 i1 + o c 0.1 ω rc=0.5ω rg=0.5ω + 0.25v 5v ba ee al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٠ fig. (18) the corresponding electrical cct of test (6) fig. (19) the corresponding electrical cct of test (7) fig. (20) the corresponding electrical cct of test (8) fig. (21) the corresponding electrical cct of test (9) -+ o c 0.1 ω rc=0.5ω rg=0.5ω + 0.25v 5v ba ee i2 i1 + o c 0.1 ω rc=0.5ω rg=0.5ω +0.25v 5v ba ee + o c 0.1 ω rc=0.5ω rg=0.5ω + 5v ba ee i2 i1 31 a 0.25v 5v+0.25 v o c 0.1 ω 0.5ω + ba ee i2 i1 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 211 high performance and low pollutant emissions from a treated diesel fuel using a magnetic field ali a. jazie al-khaledy m.sc. chemical engineering college of engineering al-qadisiya university abstract in the combustion of hydrocarbon fuel there was needing to lower the volume of unburned gases and pollutant emissions and increase combustion efficiency. the first to be oxidized are the hydrogen atoms when hydrocarbon fuel is combusted and in normal conditions some of the carbon will be only partially oxidized; this is responsible for the incomplete combustion. a magnetic field unit was manufactured for altering h atom in the hydrocarbon fuel from the stable state (parahydrogen) to the more reactive unstable state (orthohydrogen) so that transform the hydrocarbon molecule from its para state to the higher energized ortho state. in this research the pollutant emissions and combustion efficiency was studied for diesel fuel in an electrical generator (100kva) for four weeks period with and without magnetic field unit.a flue gas analyzer unit (imr 1400) was used for testing and analyze the exhaust of the electrical generator.the output data for magnetized diesel fuel was compared with the output data of normal diesel fuel and showed significant decreasing in pollutant emissions and increasing of combustion efficiency using the magnetic field unit. key words: magnetized fuel, diesel, orthohydrogen, pollutant, emissions, combustion efficiency. من احتراق وقود الديزل المعالج باستخدام المجال ةملوثال اتنبعاثتقليل اال واألداءرفع مستوى المغناطيسي علي عبد الحسين جازع ماجستير هندسة آيمياوية جامعة القادسية الهندسةآلية الخالصة الملوثـات وزيـادة كفـاءة عند احتراق الوقود الهيدروكاربوني يجب تخفيض حجم الغازات غيـر المحترقـة وانبعـاث ن االعتيادية يتأكسد جزء من الكـار بـو ف الهيدروجين وفي الضر و تإن أول جزء يتأكسد عند احتراق الوقود هو ذرا .االحتراق تم تصنيع وحدة مغنطة لتحويل جزيئات الهيدروجين في الوقود الهيـدروكاربوني مـن . جزئيا مما يسبب احتراق غير تام للوقود ولهذا تتحول جزيئات الوقود من حالة بارا إلى ) أورثوهيدروجين(إلى حالة اكثر فعالية غير مستقرة ) نبارا هيدروجي (ستقرةالحالة الم تم في هذا البحث دراسة انبعاث الملوثات وكفاءة االحتـراق لوقـود الـديزل فـي مولـد كهربـائي .حالة اورثو ذات طاقة أعلى (100kva) اسـتخدم جهـاز تحليـل .ام وحـدة المجـال المغناطيـسي ومـرة أخـرى بـدونها لمدة أربعة أسابيع مرة باستخد al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 212 النتائج لوقود الديزل الممغنط عند مقارنتها مـع نتـائج . لفحص وتحليل النواتج الغازية من المولد الكهربائي (imr1400)الغازات . تراق عند استخدام وحدة المغنطةوقود الديزل االعتيادي بينت انخفاض واضح في انبعاث الملوثات وزيادة في كفاءة االح nomenclature: eta: burning efficiency. o2 : volume content of oxygen in dry flue gas in %. qa : flue gas losses. ta : flue gas temperature. tl : combustion air temperature in degree celsius. introduction the simplest of hydrocarbons, methane, (ch4) is the major (90%) constituent of natural gas (fuel) and an important source of hydrogen. its molecule is composed of one carbon atom and four hydrogen atoms, and is electrically neutral. from the energy point of view, the greatest amount of releasable energy lies in the hydrogen atom because in octane (c8h18) the carbon content of the molecule is (84.2%). the carbon portion of the molecule when combusted, will generate (12,244 btu per pound of carbon). on the other hand, the hydrogen, which comprises only 15.8% of the molecular weight, will generate an amazing( 9,801 btu of heat per pound of hydrogen)(goodger, 1985). hydrogen, the lightest and most basic element known to man, is the major constituent of hydrocarbon fuels (besides carbon and smaller amount of sulphur and inert gases). it is the first element of the chemical periodic chart, has the atomic number 1 and atomic weight (1.0079). since it possesses only one electron, it has the valence of positive 1. it has one positive charge (proton) and one negative charge (electron), i.e. it possesses a dipole moment. it can be either diamagnetic or paramagnetic (weaker or stronger response to the magnetic flux) depending on the relative orientation of its nucleus spins. even though it is the simplest of all elements, it occurs in two distinct isomeric varieties (forms) para and ortho.it is characterized by the different opposite nucleus spins. in the para h2 molecule, which occupies the even rotation levels (quantum number), the spin state of one atom relative to another is in the opposite direction ("counterclockwise", "antiparallel", "one up & one down"), rendering it diamagnetic; whereas in the ortho molecule, which occupies the odd rotational levels, the spins are parallel ("clockwise", "coincident", "both up"), with the same orientation for the two atoms; therefore, is paramagnetic and a catalyst for many reactions. thus, the spin orientation has a pronounced effect on physical properties (specific heat, vapor pressure) as well as behavior of the gas molecule. the coincident spins render orthohydrogen exceedingly unstable. in fact, orthohydrogen is more reactive than its parahydrogen counterpart. the liquid hydrogen fuel that is used to power the space shuttle or rockets is stored, for safety reasons, in the less energetic, less volatile, less reactive parahydrogen form. during the start of the shuttle, the orthohydrogen form is beneficial since it allows to intensify the combustion processes. to secure conversion of para to ortho state, it is necessary to change the energy of interaction between the spin state of the h2 molecule. at 20°c (room temperature), 75% of hydrogen is in the para (i.e. stable) form.it is only when the liquid hydrogen temperature is dropped to -235°c that 99% of the hydrogen is in the ortho, more volatile, and unstable al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 213 (i.e. more combustibly reactive) state. obviously, keeping hydrogen fuel at this low temperature to attain the added combustion efficiency is not practical(mike r. ,1998). american rocket scientist, simon ruskin, realized that parahydrogen could be converted to higher energized orthohydrogen through magnetic stimulation, i.e. the application of the proper magnetic field to change the spin state of the hydrogen molecule. this greatly enhances the energy of the atom and the general fuel reactivity, i.e. the combustion efficiency (s. ruskin ,1958). hydrocarbons have basically a "cage-like" structure. that is why oxidizing of their inner carbon atoms during the combustion process is hindered. furthermore, they bind into larger groups of pseudocompounds. such groups form clusters (associations). the access of oxygen in the right quantity to the interior of the groups of molecules is hindered. (it has nothing to do with incoming air from the manifold in the fuel mixture when even though there may be excess of it, this will not provide the required hydrocarbon-oxygen binding.) and stemming from this shortage of oxygen to the cluster that hinders the full combustion. in order to combust fuel, proper quantity of oxygen from air is necessary for it to oxidize the combustible agents. for example, in order to totally and completely burn 1 kg of gasoline, one needs about 15 kgs of air. in the exhaust there should be then: carbon dioxide, water vapor, and nitrogen from air which does not participate in the combustion. practically, the exhaust gases contain: co, h2, hc, nox and o2(goodger ,1985). for many years, designers of the internal combustion engines have had one goal: to oppose the effect of molecular association of the hydrocarbon fuel and to optimize the combustion process. the peculiar problem in designing engines for air pollution is that in order to fully burn all the hydrocarbons in the combustion chamber, operating temperatures of the cylinders have had to be increased. while older engines may have produced relatively large quantities of unburned hydrocarbons and carbon monoxide, they produced low quantities of oxides of nitrogen. also, with the renewed interest in performance engines, compression ratios are creeping upward again, and once again the mechanism for producing higher levels of nitrogen toxins is increased. similarly, turbo charging effectively alters the compression ratio of a vehicle, further adding to the nitrogen problem.the feed and exhaust systems have been perfected, the ignition controlling electronics has been perfected, the fuel/air mix metering devices have been brought to perfection, and finally the catalytic converters have been found indispensable. but even then, fumes that leave the "afterburners" are not ideally clean engine still burns only part of the fuel (or precisely the incompletely oxidized carbon atoms in the form of co). the rest is discharged as polluting emissions (hc, co, nox) or is deposited on the internal engine walls as black carbon residue. all this has been caused by the incomplete combustion process. the reasons for it being that(magnetizer & live streams international mfg. co.,2002): 1. hydrocarbons form the so-called associations, close molecular groups, interior of which is deprived of access of the suitable amount of air; the lack of oxygen impedes the full combustion. the tendency of hc molecules to cluster causes local macro-groupings (condensing) of molecules to clog the pipes and fuel nozzles. the excess of air in the fuel mixture will not provide for the complete combustion. hence, the exhaust fumes contain considerable amounts of unburned co, hc, and soots. 2. oxygen with negative 2 valences is negative, and hydrocarbon has neutral molecular structures which by passing through steel fuel lines gets negatively (micro) charged. therefore, when these two al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 214 atoms come together with the same potential in a combustion chamber, they repel, which result in incomplete combustion. therefore, all serious research has been aimed at bringing about fuel reactivity with oxygen (oxygenated fuels); since increased oxidation means increased combustion. using the magnetic field • rule 1 : when hydrocarbon fuel (methane molecule) is combusted, the first to be oxidized are the hydrogen atoms (or precisely electrons on their outer shells). only then, are the carbon atoms subsequently burned (ch4 + 2o2 = co2+ 2h2o). since it takes less time to oxidize hydrogen atoms in a high-speed internal combustion process, in normal conditions some of the carbon will be only partially oxidized; this is responsible for the incomplete combustion.oxygen combines with hydrogen readily; however, the carbon-oxygen reaction is far less energetic. oxygen always has a valence of minus two. the valence of carbon, on the other hand, can be plus or minus due to the configuration of its four electrons in the outer shell, which requires a total of eight electrons for completion. the optimum combustion efficiency (performance) obtained from the magnetic field application on fuel is first indicated by the amount of increase in carbon dioxide (co2) produced, which has been validated by state emissions control devices. furthermore, as the pollutants decrease, the combustion efficiency increases. the drop of hc & co emissions is easily proven by comparative gas flue analysis & opacimeter emissions tests. • rule 2 : the application of the intense & focused magnetic field converts fuel molecules to a positive charge. • rule 3: altering the spin properties of the outer shell ("valence") electron enhances the reactivity of the fuel (and related combustion process). the higher energized spin state of hydrogen molecule clearly shows a high electrical potential (reactivity) which attracts additional oxygen. combustion engineering teaches that additional oxygenation increases combustion efficiency; therefore, by altering the spin properties of the h2 molecule, we can give rise to its magnetic moment and enhance the reactivity of the hydrocarbon fuel and ameliorate the related combustion process. the strong magnetic field, with sufficient flux density to have the required affect on fluid passing through it, substantially changes the isomeric form of the hydrocarbon atom from its para-hydrogen state to the higher energized, more volatile, ortho state, thus attracting additional oxygen. fuel structure and properties, such as e.g. electrical conductivity, density, viscosity, or light extinction are changed; its macrostructure beneficially homogenized. • rule 4: hydrocarbon molecules form clusters called "associations." it has been technically possible to enhance van der waals' discovery due to the application of the high power, permanent magnetic device, al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 215 strong enough to break down, i.e. de-cluster these hc associations. they become normalized & independent, distanced from each other, having bigger surface available for binding (attraction) with more oxygen (better oxidation). a simple analogy is of burning coal dust and a coal bricket. there, where one aims at higher efficiency, during the combustion process, one has to give a molecule the greater access to oxygen. in case of burning of powdered coal dust, adding of oxygen may even cause explosions. thus, with our fuel energizer, the oxygenation and the combustion efficiency increases. fuel is more active and dynamic, and the combustion process faster and more complete. these "new" hydrocarbon molecules have one more important characteristic: they not only dissolve and eliminate carbon varnish in the combustion chambers, on the surface of jet nozzles, spark plugs and exhaust pipe, but do not allow new and harmful deposits to reform. furthermore, the energizer's work ensures better performance of carburetor or fuel injectors, makes start ups easier, considerably increases driving dynamics, etc. the power and torque in the whole range of rotational velocity of crank-shaft also go up. thanks to de-clustering of hydrogen molecules, in the combustion chamber, increased saturation & reactivity of the fuel mixture with oxygen is achieved, resulting in a more complete oxidation of the primary hydrogen element and further oxidation of carbon (c), the secondary fuel element, since, in accordance with van der waals' discovery of a weak clustering force, there is a very strong binding of hydrocarbons with oxygen in such magnetized fuel, which ensures optimal burning of the mixture in the engine chamber. the positively charged fuel, so to speak, swells, thickens, and needs larger quantity of air, which is easily remedied by adjusting the change in air/fuel ratio in carbureted cars (magnetizer & live streams international mfg. co., 2002). carbon dioxide is a direct by-product of the incineration of harmful carbon monoxide gas and nitrous oxide emissions from motor vehicles are caused primarily by the conversion of oxides of nitrogen (no2) into nitrous oxide (n2o) by vehicle catalytic converters. catalytic converters were never intended to be a long term solution to the problem of air pollution caused by internal combustion engines, but rather they were adopted as a short term option, until advances in technology could offer a more effective solution. unfortunately, thirty years has passed and the automobile industry is still relying on this temporary solution ( u.s. department of energy , 1997). finally there is an innovative discovery emerging from the laboratory that makes it feasible to augment the effectiveness of the catalytic converter with a new process to lessen green house gas emissions. developed by a company called save the world air inc., and marketed under the brand name ecochargr, this revolutionary new technology has been proven effective at reducing the amount of unburned gases being expelled from internal combustion engines, resulting in a substantially lower amount of engine waste requiring incineration by catalytic converters. the processes underlying this new discovery have been validated by findings of a multi-year study sponsored by the rand corporation and conducted at temple university ( r. tao, 2005). the use of catalytic converters in passenger cars, light trucks, and heavy duty trucks since 1973 to present times has seen a complete reversal, from practically no such devices being used in 1973 to nearly all vehicles manufactured being equipped with these devices today. clearly the explanation for the global increase in ghg emissions is multivariate in nature and due (partly) to the aggregate effect of a variety of variables that include (a) an increase in vehicle miles driven annually, (b) an increase in the number of vehicles produced annually, but also and perhaps most significantly to (c) the percentage of vehicles now in use equipped with catalytic converters (united states environmental protection agency, 2001). to help mitigate the effect of global warming caused by the use of catalytic converters, it has been discovered that treatment of fuels by short pulse magnetic field, prior to combustion, has been al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 216 proven to affect changes in the molecular structure of crude oil and derivative fuels, thereby resulting in a decrease in surface tension and favorable alteration in viscosity levels. the process of exposing fuel to electric or magnetic fields subsequent to carburetion or fuel injection and just prior to combustion, has been verified to enhance the combustion process thereby increasing the exposure of fuel molecules (that are normally contained within the inner regions of fuel clusters) so that oxygen molecules can bond with more individual fuel molecules. this enhanced level of combustion, results in more fuel molecules, per cluster, being ignited and subsequently lessening the amount of unburned fuel being exhausted from the engine. this enhanced combustion process also decreases the amount of unburned fuel waste requiring incineration by the catalytic converter. such an increase in engine effectiveness also results in improved gas mileage, because more particles of fuel (per cluster) are being combusted, thereby requiring fewer clusters of fuel being needed by the engine, per mile of travel. since co2 is a natural by-product of the incineration of co, the only effective way to reduce the production of this ghg is to incinerate less co. additionally, since n2o is a natural by-product of incineration of nox, the only way to effectively reduce the production of this ghg is also to incinerate less nox ( r. tao , 2006). in april of 2006, stwa reported that the ecochargr had successfully passed euro3 emission standards, besting their previous performance, during tests conducted at the national motorcycle quality inspection & certification center in shanghai, china. (save the world air inc., 2006). the catastrophic effect caused by global warming is expected to dwarf this number and change our environment in such a way as humankind has never before experienced. global warming is expected to manifest it’s destruction in rising sea levels that displace large numbers of people throughout the world, combined with changes in average annual temperatures that result in disruptions to food supplies and increases in disease. adoption of this new magnetic treatment of fuel to lessen ghg emissions might well be the viable option if we are to avoid the catastrophic consequences that await our planet, if we fail to adopt a viable solution to global warming (world health organization, climate change report, 2001). because of the importance of magnetic devices in the energy savings there was a limitation in finding data about these devices and this research will be provide data about these devices for the first time in iraq. experimental work • the diesel generator used in the experimental work: perkins 1006 tag2 generator was used for testing. the generating set model –pl150 generates 150 kva as a prime power and 16.5 kva as standby power manufactured by fg wilson (engineering) ltd. the number of cylinders in the engine was 6-vertical in line cylinders. the combustion system was direct injection and of 4 stroke cycle. the location of the generator in the college of engineering/ alqadissyia university. • the fuel used in the experimental work: consider a diesel fuel with an extraordinarily large number of large molecules, which are associated as incipient solids in the liquid mixture. consider such a liquid-incipient solid mixture being placed into a strong magnetic field. the energy of the magnetic field will cause some, maybe just a few of the paired, opposite spinning electrons to have parallel spins. the molecules with the parallel spin components will seem strange to the molecules next to them and they will not as easily “nestle” next al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 217 each other. the iraqi diesel fuel was used in the testing. the chemical analysis of the crude oil was showed in the table (2). • the flue gas analyzer unit( imr1400): the imr1400 unit is a state of the art combustion analyzer .the unit measures gas temperature, ambient or room temperature, o2, co, draft pressure and smoke spot. all further values, as co2, coair free, excess air, efficiency and losses are calculated. the imr1400 unit is a comfortable, easy to use flue gas analyzer in robust aluminium case. all accessories needed for measuring are situated inside the case, so that an immediately readiness is guarantied. the communication with the analyzer takes place with a clear designed keyboard and a four line alphanumeric lcd with switchable backlight, so that also in dimly lit situations all values are viewable. the operation is designed as menue technic, so that it is very easy , to handle the analyzer in a short time. the imr1400 unit is equipped with a buffered memory, so that all adjustments and stored measures are also available when the instrument is switched off. the integrated printer allows to protocol directly at the measuring place. the rs232-interface allows a downloading to an pc or printer. the imr1400 unit is equipped with an automatic co-flush(option). if too high coconcentrations appears, which could destroy the sensor, the flue gas in the co-box is mixed by air with an additional pump, until the values are within the allowed range again. during this time the co value is disabled at the screen the gas flow through the imr1400 unit was shown in figure(1). to reach the highest accuracy , the analyzer should have an ambient temperature between 10 and 40 ºc. if the analyzer was at minus temperature for a longer time, switch on and let run for warm up about some minutes before measuring. proof the condensate trap. • the magnetic field unit: the magnetic field unit was manufactured locally and it’s a simple unit consist of a body from copper alloy ,inner of the body contains four magnets provides magnetic flux of (1500 gauss).the fuel flow inside the magnet pipe and the magnetic field lines cuts the fuel flow so that the fuel is magnetized. the experimental work was done on an elecrical generator of (150 kva) with diesel fuel for four weeks period. the electrical generator was a diesel generator . the emissions, gas temperature and ambient or room temperature for the combustion of diesel fuel was obtained using a flue gas analyzer unit (imr 1400). the flue gas analyzer unit was shown in figure (2). the diesel fuel was treated with magnetic field using a novel manufacured unit was suggested espicially for treating the diesel fuel using the magnetic field. the magnetic field unit was shown in figure (3) and it is place of installation on the fuel line before the fuel filter. steps of the testing 1. the electrical generator was operated for four weeks period but not continuously using diesel fuel. 2. the flue gas analyzer must be operate for (60 seconds) for calibration . al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 218 3. the set of readings was taken daily for four weeks period using the flue gas analyzer unit firstly for diesel fuel and secondly for treated diesel fuel using the magnetic field unit with the following note: • the magnetic field unit was installed properly on the fuel line before the fuel filter and leted run approximately (30 minits)before taking the set of readings. • make sure that the magnetic field unit is not in contact with the engine’s metal parts. 4. the readings was recorded using the flue gas analyzer unit for many gas temperatures and loadings. 5. the readings was printed directly using the printer of the flue gas analyzer unit with date and time of the test and using the rs232-interface was downloaded to an personal computer for analysis and graphing. results one of the main components of photochemical smog is oxides of nitrogen; oxygen depending on heat and pressure can form in differing combinations with nitrogen other than the specific nitric oxide formula. nitric oxide is a colorless gas produced by high temperature combustion; however, when it encounters extra oxygen in the presence of air and sunlight it readily converts to nitrogen dioxide (no2). nitrogen dioxide is the reddish brown haze that we associate with smog. the formula for nitrogen dioxide (no2) looks quite similar to the formula for carbon dioxide, but must bear in mind that carbon dioxide cannot support combustion while nitrogen dioxide can. nitrogen dioxide is very poisonous since the threshold lethal volume (tlv) is 3 ppm, while carbon dioxide still classified as poisonous, as a tlv of 5,000 ppm, while carbon monoxide's tlv is 50 ppm. it is quite shocking to know that nitrogen dioxide is the major component of smog and is approximately 16 times more poisonous than carbon monoxide. co: figure (4) shows the variation emissions of co with gas temperature calculated expermintally from the combustion of diesel fuel compared with the emissions of co from the same fuel treated with the magnetic field unit. it was found that for all gas temperature an immediate (approx. after 5 min upon start-up) drop in unburned hydrocarbons and carbon monoxide due to the magnetic conditioning of the fuel which makes it more reactive. as explicitly stated in instructions, upon the magnetic field unit installation in the expermintal work (5-10 minutes thereafter) engine will undergo the so-called "stabilization period", i.e. the time of the gradual disappearance of prior carbon varnish sediments and the total magnetic saturation of all ferromagnetic metal parts of the feeding system between the installed energizer and the combustion chamber in order to fully activate fuel. the initial saturation lasts about a week . no: figure (5) shows the variation emissions of no with gas temperature from the combustion of diesel fuel compared with the emissions of no from the same fuel treated with the magnetic field al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 219 unit. it was found that for all gas temperature the no concentration lower with magnetized fuel because there is very little oxygen left to produce any additional toxic compounds with nitrogen. nox: figure (6) shows the variation emissions of nox with gas temperature from the combustion of diesel fuel compared with the emissions of nox from the same fuel treated with the magnetic field unit. it was found that for all gas temperature the nox concentration lower with magnetized fuel. one of the chief reasons for the magnetic field to have possibility to lower the nox level, as found expermintally is due to the low reactivity of nitrogen gas. if we can bind up all the available oxygen with the hydrocarbon fuel, there simply will be no oxygen left over to form the unwanted nitrogen burning efficiency : the values of excess air, burning efficiency, and losses are calculated in the memory of imr1400 unit and not calculated manually. the calculation of the flue gas losses was based on the equation (1) and table(1) (instruction manual ,hl860 ,exhaust analysis device, 2002): ) 9.20 ()( 2 2 b o a ttq laa +− ∗−= (%) …eq.(1) the burning efficiency was calculated using the equation (2): aqeta −= 100 (%) …eq.(2) for the free selectable fuel the calculation of losses was calculated using the equations(3)and (4) (instruction manual ,hl860 ,exhaust analysis device, 2002): 2 )( co tt fq laa − ∗= (%) …eq.(3) 038.02 ∗= cof (%) …eq.(4) figure (7) shows the variation of burning efficiency with gas temperature from the combustion of diesel fuel compared with the burning efficiency for the same fuel treated with the magnetic field unit. it was found that for all gas temperature the burning efficiency higher with the magnetic field unit. the highest burning efficiency was achieved at the highest carbon dioxide level, since carbon dioxide cannot be subsequently oxidized. the purpose of a catalytic converter is to reduce all carbon monoxide to carbon dioxide. the amazing part is that the magnetizer reduces emissions on cars with catalytic converters. the increased combustion efficiency was occurred within the engine due to increased fuel reactivity with oxygen (increased oxidation), the main factor responsible for increased combustion efficiency. it was a complete waste to allow an engine to run inefficiently and to burn the excess carbon monoxide in it's al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 220 catalytic converter, the wasted heat merely "heats-up" the exhaust system, instead of providing useful work within the engine.by establishing proper fuel burning parameters by magnetic means, we can be assured that an internal combustion engine was getting the maximum energy per gallon of fuel. the temperature variation was effected by electrical load variation. comparison between the results of the research with the other data: the comparison of the results with the data of (greg, (2000)) obtained from detroit diesel 11.1mine engine was showed in the table (3). the variation of the results resulted from the differences between the two magnetic field units used in the shape of magnates and strength of the magnetic field. conclusion the experimental results showed : 1. magnets applied to hydrocarbon fuel lines appears to reduce fuel consumption. 2. magnets applied to hydrocarbon fuel lines appears to improve emission quality due to more complete combustion. 3. diesel engine operation will improve significantly. 4. the burning efficiency higher with the magnetic field unit 5. magnets applied to hydrocarbon fuel lines appears to interrupt the solidification process so that there will not be so many “almost-solid” particles in the liquid. 6. as documented by tests, the magnetic treatment of fuel has reduced the production of nox by 20% ,no by 5% and co increased by 2% . 7. less refueling time and longer operating times. references goodger, e., and vere, r., 1985, ”aviation fuels technology”, macmillan publishers ltd., greg baiden , 2000, journal of energy and fuels ,magnetic technology applied to improve combustion. instruction manual ,hl860 ,exhaust analysis device, 2002 magnetizer & live streams international mfg. co.,2002. mike r. powell, 1998, skeptical inquirer magazine, magnetic water and fuel treatment: myth, magic, or mainstream science. r. tao, 2005, journal of modern physics, viscosity reductions in liquid suspensions by electric of magnetic fields. r. tao, 2006, journal of energy and fuels, reducing the viscosity of crude oil by pulsed electric or magnetic field. save the world air inc., 2006. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 221 s. ruskin, 1958, u.s. utility patent no. 328,868. u.s. department of energy, energy information administration, emissions of green house gases in the u.s., 1997. united states environmental protection agency, methodology for estimating emissions of ch4, n2o, and criteria pollutants from mobile combustion, annex e, 2001. world health organization, climate change report, 2001. table (1) : the values of parameters in the equation(1) for a variety of fuels. oil light natural gas town gas coal gas liquid gas coal wood dry co2max 15.5 11.8 11.6 12.5 13.5 20.5 20.5 a2 0.68 0.66 0.63 0.6 0.63 0.65 0.65 b 0.007 0.009 0.011 0.011 0.008 0.008 0.008 ref o2 3% 3% 3% 3% 3% 7% 11% table (2): the chemical analysis of the crude oil element wt% carbon hydrogen sulfur nitrogen oxygen metals 85 14 0.38 0.1 0.5 0.02 table (3): the comparison between the experimental results and greg results. nox%, decreased no%, decreased co%, decreased experimental results 20 5 -2 greg results 15 3 -4 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 222 figure(1): the gas flow through the flue gas analyzer unit (imr 1400). figure(2): the flue gas analyzer figure(3): the installed magnetic field unit unit (imr 1400). al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 223 figure(4): co emission concentration for diesel fuel and magnetized diesel fuel. figure(5): no emission concentration for diesel fuel and magnetized diesel fuel. gas temperature 50 100 150 200 250 300 [n o ],p pm 100 200 300 400 500 600 700 800 900 [no],ppm [no],ppm,magnetized fuel gas temperature 50 100 150 200 250 300 [c o ],p pm 20 30 40 50 60 70 [co],ppm [co],ppm,magnetized fuel al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 224 figure(6): nox emission concentration for diesel fuel and magnetized diesel fuel. figure(7): burning efficiency for diesel fuel and magnetized diesel fuel. gas temperature 50 100 150 200 250 300 [n o x] ,p pm 100 200 300 400 500 600 700 800 900 [nox],ppm [nox],ppm,magnetized fuel gas temperature 50 100 150 200 250 300 b ur ni ng e ff ic ie nc y, % 70 75 80 85 90 95 100 105 burning efficiency,% burning efficiency,magnetized fuel,% al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 451 evaluation of surface water quality in al kufa river station dr. hussein abdulmuttaleb ali khan lecturer at university of kufa/ eng. college absract the principal reason for monitoring water quality has been, traditionally, the need to verify whether the observed water quality is suitable for intended uses. the present study was conducted on al kufa river in al-kufa city in the aim of studying the concentration levels of some water quality parameters (bod, po4, no3, ph, tu, cl, and dust particles). samples of raw water were collected and analyzed from kufa river station during a period of eight months, starting from november until june 2010. the purpose is to assess the level of parameters measured and their effects on the river. statistical analysis used to describe the relations between parameters of water quality with regression analysis done by using "data fit" program version 9.0 software. this study showed that the discharging of domestic sewage, detergents, agricultural effluents with fertilizers and industrial waste water from adjacent areas causing some contaminants increased. it was noticed that the no3 has highest positive correlation with po4 and ph has highest negative relation with po4 and no3, finally, precipitated dust particles have highest negative correlation with ph as a result of acidic chemicals in dust particles. keywords: water quality, turbidity unit, bod, phosphate, nitrate, hydrogen ion concentration, chloride, dust particles, regression models. 2010 hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 452 "data fit" program version 9.0 software 1.introduction water is vital for life. not only do we need water to drink, to grow food and to wash, but it is also important for many of the pleasant recreational aspects of life. each different use has its own requirements over the composition and purity of the water and each body of water to be used will need to be analyzed on a regular basis to confirm its suitability (reeve, 2002). aside from the very important issue of clean drinking water, why care about clean water? clean water and enough of it is essential to any and all life, animals, plants, and microbes. indeed, there are places in the world where the water is so polluted that fish have disappeared. in many other places fish or shellfish survive, but are not safe to eat because their flesh is contaminated. humans enjoy being around water, but contamination with infectious organisms makes swimming unsafe; or if water has obnoxious odors or scum, being near it is not pleasant. clean water is vital (hill, 2004). historically, the environmental engineer has found ways and means to provide ample quantities of quality drinking water for domestic use as well as quality water for commercial and industrial uses. water supply issues include demand projections, quality requirements, surface water and groundwater source evaluations, groundwater production, surface water collection, surface water treatment, saline water treatment, no conventional water production, and treated water distribution (corbitt, 2004). water pollutants are categorized as point source or no point source, the former being identified as all dry weather pollutants that enter watercourses through pipes or channels. storm drainage, even though the water may enter watercourses by way of pipes or channels, is considered non point source pollution. other non point source pollution comes from agricultural runoff, construction sites, and other land disturbances (weiner and matthews, 2003). water, of course, is used for many purposes associated with human activity. in its natural state it occurs in and on the ground in subsurface and surface reservoirs. the quality and reliability of a source of water will vary considerably, both in time and space. this means that characteristics (chemical, physical, and biological) will evaluation of surface water quality in al kufa river station 453al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 differ greatly depending upon the location and type of source. it also means that a given source may vary over the seasons of the year (pfafflin and ziegler, 2006). many studies were carried out for different rivers in the world in different forms. bhargava (1983) studied the quality of ganga and yamuna rivers. he found that the assimilation of biochemical oxygen demand (bod) after the waste outfalls at the urban centers along these rivers was found to be exceedingly fast. during the two stage bod removal in these streams, the early reaches, resulted from bioflocculation of waste colloidal matter with river. morrison, 1987, showed that heavy metals in natural waters may occur as organic and inorganic complexes of varying sizes, or be associated with colloidal or particulate material of a heterogeneous nature. euphrates river has a large importance for iraqi environment researchers because of the detrimental effect of pollutants resulting from treated and untreated domestic wastewater, treated and untreated industrial wastewater and farming and agricultural pollutants. chabuk, 2009, studied the evaluation of selected trace elements in shatt al hilla river a branch of euphrates river. he showed there is a slight variation in the concentration of trace metals between the selected locations in his study. this may be attributed to the movement of pollutants along the river and the similarity of human activities and agricultural wastes disposed to these locations. obais, 2010, studied water quality assessment in middle-euphrates region in iraq with various locations and different water bodies such as rivers, lake, and drains , showed an environmental assessment procedure is necessary to further characterize conditions of water quality in the middle euphrates region. 2. objectives the objectives of the study are: i. to characterize the water quality of shatt al kufa station ii. to identify the effects of some pollutants discharged by different sources on river. 3. study area kufa is a city in iraq, about 170 kilometres (110 mi) south of baghdad (capital of iraq), and 10 kilometres (6.2 mi) northeast of najaf. it is located on the banks of the euphrates river. euphrates river branches after al-kifil town directly about (1km) to two branches (first one is shatt al kufa and another branch named al abbasia river). the main source of water for this river is rain water, stored water as lake and reservoirs. al kufa station is located on the river euphrates / shatt al-kufa, near the al kufa water treatment plant for surface water monitoring, at coordinates (e044.4075, n32.03941). the water level at the station is not stable at a certain depth, according to the season of the year, in the summer decline is attributed to its lowest level so that the bottom of the river can be seen in some areas near the station, and even in winter the water levels are not rising as required, and the center of the river is not covered with water even in winter and the rainy season (figure 1). the nature of the land surrounding the station is agricultural land, with some residential buildings at a distance (100 m to the south) and farming land on the other side. al kufa river passes through many towns and villages thus it represents the main source for different uses such as: hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 454 a. water supply systems: the river represents the supply source for many water treatment plants such as al-najaf and al-kufa water treatment plants. b. irrigation: the river is the main source of the irrigation for large agricultural areas locating on both sides of the river. c. industrial purposes: the river represents the main source for all industrial activities in the area. in addition to these main uses, the river receives many pollutants discharged by different sources, including: a. municipal wastes: municipal wastes are discharged from northern drainage of al kufa ) 2 km / north) and raw waste water discharged from al jimaah zone at 1 km / north of station. b. careless use of pesticides can contaminate water sources and make the water unsuitable for drinking. wastes of animals and plants from agricultural areas are discharged to the river on both sides. c. industrial wastes: many industries discharge wastewater to the river such as soft drink factory and many private industries. 4. water quality parameters used this research covers the study and analysis of monthly water quality parameters which are listed in table 1 of surface water for river (euphrates/ shatt al kufa). the water quality parameters used in present study will be described below: 4.1 bod the amount of oxygen required o oxidize a substance to carbon dioxide and water, and if the oxidation of an organic compound is carried out by microorganisms using the organic matter as a food source, the oxygen consumed is known as biochemical (biological) oxygen demand (bod) (davis and cornwell, 2008). the bod determination has been standardized and measures the amount of oxygen utilized by microorganisms in the stabilization of water for five days at 20 °c. for domestic sewage the 5-day value or bod5 represents approximately 2/3 of the demand which would be exerted if all the biologically oxidizable material were, in fact, oxidized (steel and mcghee, 1979). 4.2 phosphate nutrients are chemicals, such as nitrogen, phosphorus, carbon, sulfur, calcium, potassium, iron, manganese, boron and cobalt that are essential to the growth of living things. in terms of water quality, nutrients can be considered as pollutants when their concentration is sufficient to allow excessive growth of aquatic plants, particularly algae (lal, 2009). phosphorus is present in fresh waters mostly in inorganic forms such as phosphates. however, being an important constituent of biological system, it may also present in the organic form. the major sources of phosphorus are domestic sewage, detergents, agricultural effluents with fertilizers and industrial waste water. higher concentration of phosphorus, therefore, is indicative of pollution (duggal, k.n., 2008). 4.3 nitrate evaluation of surface water quality in al kufa river station 455al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 the two nutrients of importance in water/wastewater are nitrogen and phosphorus. they are both essential nutrients for plant and organism growth, but in excess they can be undesirable, often leading to eutrophication. nitrogen cycles present in inorganic and organic forms. the inorganic form of nitrogen of key interest is: n2, nh3, and no3 ¯. the organic forms of nitrogen of interest are: nh3, no2 ¯ , and no3 ¯ . plants have the ability to fix n2 and convert it to nitrates. animals cannot utilize inorganic nitrogen or nitrogen from the atmosphere, unless it is first converted into its organic form. nitrates in drinking water are harmful, and upper limit values of 40 mg/l are typical for drinking water (kiely, 1997). excessive nutrients often lead to large growth of algae, which in turn become oxygen-demanding material when they die and settle to the bottom (davis and masten, 2004). 4.4 ph it is the logarithm to the base 10 of reciprocal of hydrogen ion concentration expressed in gms./litre. the ph value of neutral (pure) water is 7.0 and when it is less than 7.0 it is acidic in nature while above 7.0 is alkaline in nature. too low or too high ph values are both undesirable an hence it is imperative to have the ph value of the water around neutral value. the ph of natural waters depends upon the co2 equilibrium and lies between 7.0 and 8.0 to 8.5. the ph of distilled water may be 6.5 or lower, because of co2 solution in it ( lal, 2009) . 4.5 turbidity turbidity is measured in units that relate the clarity of the water sample to that of standardized suspension of silica. the interference in the passage of light caused by suspension of 1 mg/l of silica is equivalent to one turbidity unit (tu). to interpret turbidity data, it is useful to be familiar with the typical ranges that occur. turbidity in excess of 5 tu is just noticeable to the average person, most people do not complain about the clarity of the water at tu values less than 5. turbidity in what most people would consider to be a relatively clear lake may be as high as 25 tu. in muddy water, turbidity generally exceeds 100 tu. modern water treatment plants can routinely produce crystal water with turbidities of less than 1 tu (nathanson, 2000). 4.6 chloride chloride in natural water results from the leaching of chloride-containing rocks and soils with which the water comes in contact and in coastal areas from saltwater intrusion. in addition, agricultural, industrial, and domestic wastewaters discharged to surface waters are a source of chlorides (metcalf & eddy, 2004). chlorides found in domestic sewage is derived from kitchen wastes, human faces and urinary discharges etc., human excreta, for example, contains about 6 g of chlorides per person per day (punmia and jain, 1998). 4.7 precipitated dust particles airborne particulate matter represents a complex mixture of organic and inorganic substances. particulate matter is emitted in urban areas from power plants, industrial processes, vehicular traffic, domestic coal burning and industrial incinerators (kiely, 1997), also particles in the atmosphere can come from windblown dust (boubel et. al., 2008). water quality managers are concerned with knowing how water quality is affected by natural factors such as the geometry of the terrain, and the climate of the region (davis and masten, 2004). hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 456 hence, present study considered the precipitated dust particles in study area in order to identify its effect on the water quality and relations between parameters involved through statistical analysis. 5. model formation data of water quality of the euphrates river (at kufa river station) are being analyzed monthly, and the pollution levels are being determined. in present study the statistical models are described the relations between parameters of water quality. the regression analysis was done by using "data fit" program version 9.0 software. also, two statistical methods were utilized for analyzing data collected from the sampling site: correlation analyses, regression variable (t-ratio and prob(t)), and variance analyses (prob(f)). correlation analyses were performed on the individual water quality parameters to identify relationships between them. variance analyses to determine the overall significance of the regression model accordingly, multiple non-linear regression models in three forms were used for each design requirements to choose which form gives the best fitting of data. the regression models that were proposed and investigated can be seen in table 2. 6. data analysis data for euphrates river in al kufa station were collected, from the period extended from november to june 2010. these data represent the phosphate (po4), nitrate (no3), hydrogen ion concentration (ph), turbidity unit (t.u.), chloride (cl), precipitated dust particles (pm, g/m 2 ) as independent variables, and biological oxygen demand (bod), as dependent variable, as shown in table 3. table 4 shows the data statistics of water quality parameter used, while the correlation matrix is shown in table 5. the optimum correlation equation from rank a in an exponential form with coefficient of determination r 2 equal to 0.2465 was shown in table 6, and table 7 shows regression variables results and 95% confidence intervals. finally, (anova) analysis is shown in table 8. fig 2 shows the plot model of euphrates river at al kufa station. 7. discussion from table 5 bod in station has poor negative relation with turbidity unit and poor positive relation with phosphate, while no3 has highest positive correlation with po4, because of they are together represent major nutrients found in domestic sewage that discharged to al kufa river from northern drainage of al kufa (2 km/north) and raw waste water discharged from al jimaah zone at 1 km / north of station . ph has highest negative relation with po4 and no3, apparently as a result of discharging of domestic sewage mentioned above and the wastewater effluent from the water softening factory precede the station causing altering the concentration in the kufa water body. negative correlation between turbidity and phosphate was found, this results can be explained by considering the discharging domestic sewage, detergents, agricultural effluents with fertilizers and industrial waste water from adjacent areas which represent major sources of phosphates that affecting turbidity value with considering tiny fragments of organic matter with clay and silt cause turbidity. evaluation of surface water quality in al kufa river station 457al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 precipitated dust particles have highest negative correlation with ph as a result of acidic chemicals in dust particles resulting from gases emitted from numerous illegal private brick factories. some chemical substances exist as dry particles in the air while others enter water body as wet particles such as rain, snow, sleet, hail dew or fog (meenambal et. al., 2005). particles may be precipitated directly to the river or indirectly, such as with rain that falls on land is drained through the sewage system eventually make their way into river. the introduction of these acids and chemicals into river causes a sudden drastic change in the ph value. figures 3 and 4 show the variation of bod and phosphate levels in the river water during the period of the study. all values measured are below the allowable iraqi limits for rivers, less than 5 mg/l and 3 mg/l respectively (values detailed in table 4). figures 5 and 6 illustrate nitrates and ph; also, all values are at acceptable limits. figure 7 shows the turbidity concentration during period of study, highest value occurs in june was 47.7 ntu, while iraqi standard is (1018 ntu), all measured values were allowable. chloride values throughout the period of the study shown in figure 8, values ranged between (153.8-236.9 mg/l), highest level was at may, as a result of pesticides used for agriculture in adjacent land while iraqi standard is 200 mg/l. table (9) shows the allowable limits of water quality parameters in river water body and drinking water according to iraqi, who, us epa, and canadian standard. most values measured agreed well with the limits given in table 9. 8. conclusions the following conclusions are drawn on the basis of the results obtained from the present analysis: it was found, bod and chloride have poor relation with other parameters used, also, it was noted that moderate existence of its concentration in kufa station compared with local and international allowable limits of water quality parameters. it was found that there is highest positive correlation between no3 and po4. also, ph has highest negative relation with po4 and no3, these results can be explained by considering the discharging of domestic sewage and the wastewater effluent from some industrial activities to the river. negative correlation between turbidity and phosphate was found. it was found that there is a negative relation between dust concentration and hydrogen ion, agreed well with obais, 2010, and also with nitrates, while poor relation was found with phosphate, turbidity and chloride. 9. recommendations -environmental monitoring programs to control the water quality of al kufa river, and how they are affected by various environmental factors. -further studies on other potential pollutants in al kufa river and the hydrocarbon compounds such as pesticides and other residues in the river water and sediment. -more studies on the relationships between air pollution from industrial and traffic sources, and trace elements concentration within river water and sediment. -conduct more studies on the relationships between different types of pollutants and human and animal health. hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 458 10. references bhargava, d. s., 1983, "most rapid assimilation in ganga and yamuna rivers ". journal of environmental engineering division, asce, 109(1): 174-188. boubel, r. w., fox, d. l., turner, d. b., stern, a.r c., vallero, d. a., 2008,"fundamentals of air pollution" fourth edition, elsevier inc. chabuk, a. j., 2009, " evaluation of selected trace elements in shatt al hilla river", m. sc. thesis, college of engineering, university of babylon. corbitt, r. a. "standard handbook of environmental engineering", mcgraw-hill (www.digitalengineeringlibrary.com) , 2004. davis, m. l., and cornwell, d.a., 2008 "introduction to environmental engineering " , fourth edition, mcgraw-hill. davis, m. l., and masten, s. j., 2004 "introduction to environmental engineering " , mcgraw-hill. duggal, k.n., 2008, "elements of environmental engineering", s. chand&company ltd. hill, m. k., 2004, " understanding environmental pollution", cambridge university press. hocking,,martin b., 2005, "handbook of chemical technology and pollution control",third edition, elsevier inc. kiely, g., 1997, "environmental engineering", mcgraw-hill, international (uk) limited. lal, d., 2009, "water supply and waste water engineering", s. k. karatia & sons, new delhi. liu , i., 1999, " environmental engineers handbook", crc press llc masters, g, m., and ela, w., p., 2008, "introduction to environmental engineering and science",3 rd edition prentice hall, inc. meenamble, t., uma, r. n., and murali, k., 2005, "principles of environmental science and engineering", s. chand & company ltd, new delhi. metcalf & eddy, 2004, " wastewater engineering treatment and reuse", fourth edition, mcgraw-hill. ministry of environment, iraq, iraqi environmental legislations book. morrison, g. m. p., 1987, "approaches to mater speciation analysis in natural water, sediment and soil systems", springer-verlage, new york. http://www.digitalengineeringlibrary.com/ evaluation of surface water quality in al kufa river station 459al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 nathanson, j. a., 2000," basic environmental technology", prentic-hall, inc. obais, a. a., 2010, " water quality assessment in middle-euphrates region in iraq", m. sc. thesis, college of engineering, university of babylon. (obais, , 2010) pfafflin , j. , and ziegler, e.n., 2006, "environmental science and engineering", crc press taylor & francis group. punmia, b. c., and jain, a. k., 1998, "wastewater engineeringincluding air pollution", laxmi publications (p) ltd-new delhi. reeve , r. n., 2002, " introduction to environmental analysis ", university of sunderland, john wiley & sons, ltd. salvato, j. a. , dee, p.e., nemerow, n. l., and agardy , f. j., 2003," environmental engineering", fifth edition, john wiley & sons, inc. steel, e. w., and mcghee, t. j., 1979, " water supply and sewerage", fifth edition, mcgraw-hill. weiner, r. e, and matthews, r. a. , 2003, "environmental engineering", fourth edition, elsevier science (usa). table 1 water quality parameters which are used in this study parameter symbol unit biological oxygen demand bod mg/ l phosphate po4 mg/ l nitrate no3 mg/l hydrogen ion concentration ph hydrogen ion concentration turbidity tu ntu chloride cl mg/ l precipitated dust particles pm g/m 2 /month table 2 the proposed models. rank equation description a m)xj...bxexp(axy kk21  b mxj...bxaxy kk21  c kk21 xj...xbxay  where; y = dependent variables. x1, x2, …, xk = the independent variables. a, b, c, …jk = are model coefficients, and m = model constant term. hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 460 table 3 description of independent and dependent variables in al kufa river station. table 4 data statistics of variables in al-kufa station variable x1 x2 x3 x4 x5 x6 y number of points 8 8 8 8 8 8 8 missing points 0 0 0 0 0 0 0 maximu m value 0.17 11.1 8.5 47.7 236.9 197.5 1.56 minimu m value 0.05 7.9 7.3 5.9 153.8 15.33 0.91 range 0.12 3.2 1.2 41.8 83.1 182.17 0.65 average 0.105625 8.8425 7.76875 14.9375 200.65 108.3575 1.215 standard deviation 0.0428816 89 0.9631903 83 0.3826015 27 14.001218 06 25.389480 39 67.336704 86 0.1933169 12 table 5 correlation matrix of variables in al-kufa station correlation matrix x1 x2 x3 x4 x5 x6 y x1 1 x2 0.57894986 1 x3 -0.5754979 -0.557396 1 x4 -0.3047245 -0.217717 0.079453 1 x5 -0.0964742 -0.235383 0.072612 -0.083726 1 x6 -0.0976143 -0.304151 -0.448784 0.143449 -0.12878 1 y 0.07884085 0.21083 -0.368425 -0.120786 0.173557 0.163968 1 table 6 model selected of variables in al-kufa station model std. error residual sum residual avg. rss r 2 exp(a*x1+b*x2+c*x3+d*x4+e*x5+f*x6+g) 0.44396 0.00262 0.00033 0.1971 0.2465 type of variables variables detail x1 phosphate (po4, mg/l) x2 nitrate (no3, mg/l) x3 hydrogen ion concentration (ph) x4 turbidity unit (t.u., ntu) x5 chloride (cl, mg/l) in d ep en d en t x6 precipitated dust particles(pm, g/m 2 /month) dependent y biological oxygen demand (bod), mg/l) evaluation of surface water quality in al kufa river station 461al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 table 7 regression coefficients results and 95%confidence intervals regression variable results var. value standard error t-ratio prob(t) a -1.15428204598879 4.63880197013395 -0.24883193 0.84474 b 2.57272568082175e-02 0.306630909038197 0.083903012 0.94671 c -0.210957288638414 0.890306811982229 -0.236948977 0.85189 d -1.57638676748872e-03 1.07365540860054e-02 -0.146824275 0.90719 e 1.06726909016662e-03 6.44172699694457e-03 0.165680584 0.89547 f 4.60759543139453e-05 4.17928764012567e-03 0.011024834 0.99298 g 1.52921066131658 10.4046948661851 0.146973139 0.9071 table 8 variance analysis of variables in al-kufa station variance analysis source df sum of squares mean square f ratio prob(f) regression 6 6.449608182228e-02 0.01074934697038 0.054536445 0.99481 error 1 0.19710391817772 0.19710391817772 total 7 0.2616 table 9 allowable limits of water quality parameters in river water body and drinking water according to iraqi , who, us epa, and canadian standards water standards p a ra m et er unit iraqi* drinking water standards iraqi * river water stand. who* * drinking water standards u.s. ** envir. protection agency, 1994 drinking water stand. canadian * * guidelines for drinking water quality (1987) bod mg/ l none < 5 none none none po4 mg/ l …… < 3 ……. …… ……. no3 mg/l 0 40 50 10 10 10 ph hydrogen ion conce 6.5-8.5 6.5-8.5 6.5-8 6.5-8.5 6.5-8.5 tu ntu < 10 10-18 5-25 1 1 cl mg/ l 200 200 250-600 250 < 250 95% confidence intervals var. value 95% (+/-) lower limit upper limit a -1.15428204598879 58.941545592916 -60.0958276389048 57.7872635469272 b 2.5727256808e-02 3.89611365642113 -3.87038639961292 3.92184091322935 c -0.21095728863841 11.3124164144086 -11.523373703047 11.1014591257702 d -1.576386767e-03 0.136420803527602 -0.13799719029501 0.134844416760114 e 1.067269090e-03 8.184987156857e-02 -8.0782602478e-02 8.29171406587e-02 f 4.6075954313e-05 5.310286461296e-02 -5.3056788658e-02 5.3148940567e-02 g 1.52921066131658 132.204133908722 -130.674923247405 133.733344570038 hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 462 * source: iraqi environmental legislations book ** source: (liu , 1999) figure 1 map of the studying area in the national context. evaluation of surface water quality in al kufa river station 463al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 figure 2 plot model of water in al kufa station figure 3 variations of bod with time variation of po4 with time 0 1 2 3 4 nov dec jan feb mar apr may jun time (month) p o 4 , m g /l po4 concentration iraqi standard figure 4 variations of po4 with time hussein abdulmuttaleb ali khan al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 464 figure 5 variations of no3 with time figure 6 variations of ph with time figure 7 variations of turbidity with time evaluation of surface water quality in al kufa river station 465al-qadisiya journal for engineering sciences, vol. 5, no. 4, 451-465, year 2012 figure 8 variations of chloride with time a, b, c, …jk = are model coefficients, and m = model constant term. table 3 description of independent and dependent variables in al kufa river station. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 tribological performance of highly fine nickelmolybdenum disulfide powders additive to lubricant oil dr. haidar akram hussien lecturer technical college baghdad foundation of technical education e-mail׃ drhaidar3@yahoo.com abstract wear is a phenomenon which is surface materials damage or loss between two contact solids surfaces in sliding, rolling, or impact movement. in most cases, wear is caused by the interaction of surface asperities. to reduce the energy loss and equipment damage generated due to the mechanical parts friction in the operation, around the world is stepping up developing appropriate lubricants and lubrication technology. molybdenum is one of the major refractory metals (metals with very high resistance to heat and wear). as already noted, for lubricant compositions as fillers can be used soft powder (anti-friction) of metals – nickel. this work focuses on studying an urgency and favorable prospects of practical use of firm powder additives on the basis of mos2 which particles are coated with one layer of soft metal (ni), and their effect on tribological characteristics of lubricant oil (sae 50) at a range of concentration (2 – 8) wt%. optimum lubricating effect concluded on the level of concentration of the composite additive powder in the range of (3.5 – 4.5) wt %, by the formation of protective boundary layer between sliding tribosurfaces that prevents wear. tribological characteristics significantly improved i.e.friction coefficient may drop about (1.5-2) times, and the wear rate about (3-3.5) times compared with the case of usig the lubricant oil without additives. keywords: tribological properties, additives, coating, lubricating effect, solid lubricant. مليبدنيوم عالي النعومة على كبريتيد ال ثنائي–دراسة تاثير اضافة مسحوق نيكل الخواص التريبولوجية لزيوت المحركات حيدر اآرم حسين .د مدرس بغداد– الكلية التقنية /هيئة التعليم التقني موجزال لتقليل و،ء المتالمسه من الظواهر المهمه الجديره بالدراسه السيما بين اسطج االجزايعتبر االستهالك بين بسبب التشغيل الميكانيكي واالحتكاك الحاصل واالنهيارات الحاصله الحاصلة في الطاقهالضياعات الخواص التريبولوجيه لمواد بدا العلماء بالعمل اليجاد بعض البدائل والحلول لتحسيناالجزاء المنزلقه haidar akram hussien ويعتبر عنصر المليبدنيوم من )وضغط عالييندرجة جراره (التزييت خصوصا في بعض الظروف الخاصه يتناول هدا ·العناصرالرئيسيه في هدا المجال بسبب تركيبه البلوري ومقاومته العاليه للحراره واالستهالك مسحوق مركب معامل ( عالي النعومه) نيومثنائي كبريتيد المليبد -نيكل (البحث دراسة تاثيراضافة مسحوق ،) النيكل –المعدن الناعم مغلفه بطبقه رقيقه منق مسحوق ثنائي كبريتيد المليبدنيوميث تكون دقائكيميائيا بح – 2( وبتراكيز مختلفه تتراوح بينالخواص التريبولوجيه للزيتعلى ،)sae 50 (الى زيت المحركات نوع رت النتائج د اظه لق· من خالل حساب معامل االحتكاك بين السطوح المنزلقه ومعدل االستهالكلتر/غم)% 8 الطبقه بسببامكانيه عاليه في تحقيق هدف البحث المتمثل بتحسين الخصائص التريبولوجيه للزيت المستخدم تعمل على زيادة المساحه السطجيه للسطوج المتالمسه وبالتالي التي ند االسطح المتالمسهالواقيه المتكونه ع ومعدل االستهالك مره ) 2 1.5( بحدود االحتكاك فقد انخفضت قيمة معامل،نقليل االحتكاك واالستهالك ثنائي كبريتيد -نيكل ( مسحوق لتر من/غم )%4.5 -3.5( على التوالي ودلك باضافة مره)3.5 -3( بحدود · الى الزيت بالمقارنه مع الحاله عند استخدام الزيت بدون اضافات )المليبدنيوم introduction powder lubrication has been employed as a suitable dry lubricant in a variety of sliding contacts as an alternative to conventional liquid lubricants. the essential postulate of this alternative approach is that there are two operative elements, hydrodynamic and morphological. the hydrodynamic element refers to the layered shearing of particles between sliding tribosurfaces, where as the morphological element refers to the effects due to the mechanical, chemical, and tribological surface phenomena characteristic of the mating materials [zhang, 2010]. the term “powder lubricants” is usually given to those lamellar solids that have low interlayer friction. some of the interesting attributes of powder lubricants that are worth noting are that they have been known to adhere to surfaces forming a protective boundary layer that prevents wear, act like a lubricant in sliding contacts by accommodating relative surface velocities, and are capable of lubricating at high-temperatures. several of these powder lubricants—molybdenum disulfide, tungsten disulfide, titanium oxide, boron nitride, and boric acid— were evaluated for their lubrication behavior in extreme-environments (i.e., high speeds ~ 45m/s, high temperature ~ 400°c) [godloviski, 2008 and taylor, 2000]. wear is a phenomenon which is surface materials damage or loss between two contact solids surfaces in sliding, rolling, or impact movement. in most cases, wear is caused by the interaction of surface asperities. to reduce the energy loss and equipment damage generated due to the mechanical parts friction in the operation, around the world is stepping up developing appropriate lubricants and lubrication technology [washida, 2003 and hoshi, 1994]. molybdenum is one of the five major refractory metals (metals with very high resistance to heat and wear). the other refractory metals are tungsten, tantalum, rhenium and niobium. molybdenum's strength and resistance to expanding or softening at high temperatures is particularly sought after in critical areas where high temperatures are common, such as in nuclear power plants and aircraft engines [holinski, 2003 and taylor, 1997]. nickel-based sintered composites produced by powder metallurgy processes are now widely used in tribological engineering parts, e.g. bearings and bushes. also composites based on nickel molybdenum disulfide alloys containing a solid lubricant have been developed as self-lubricating materials under extreme conditions of load, atmosphere and temperature. it is well known that the addition of molybdenum disulfide serves to reduce friction and wear in nickel–molybdenum disulfide alloys. however it should be noted that the addition of molybdenum disulfide (mos2) has an adverse effect on the composites’ mechanical properties [godloviski, 2008 and popczyk, 2006]. the lubricant mos2 powder was coated with ni to al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 112 tribological performance of highly fine nickel-molybdenum disulfide powders additive to lubricant oil reinforce their bonding to the ni particles in the composites during sintering. the hardness, microstructure and bending strength of the sintered specimens were changed. the friction and wear properties of the materials were clearly decreased. although mechanical properties of the composites decreased with increasing amount of added mos2, the use of ni-coated lubricant powders improved the bending strength. molybdenum disulfide was very effective in reducing the wear and friction of the composites [rafal, 2011 and budniok, 2007]. this work focuses on studying urgency and favorable prospects of practical use of firm powder additives on the basis of molybdenum disulfide which particles are coated with one layer of soft metal (ni), and their effect on tribological characteristics of lubricant oil. experiment procedure the tribological characteristics of investigated metal-molybdenum disulfide additives to lubricant oil with single-layered coating were received during wide range of experiments. study of tribological characteristics of the developed lubricant compositions was performed on a friction machine model cmt-2. a simplified diagram is shown in figure 1 [godloviski, 2008]. friction moment on the shaft (rotating disk) was measured using an inductive sensor. electrical signals werefed into the electrical circuit and then compared to the potentiometer readings, mounted in anelectrical controlcabinet. testing samples were made of steel 45, hardness 40-42, dimensions l x b x h = (10 x 10 x10 mm). all samples had a same surface roughness. the roller was d = 40 mm diameter, 15 mm thick, made of steel 45, hardness 35─ 40. friction conditions [godloviski, 2008]: the rate of slip-(2m / s) was not changed during the tests, the load on the sample increased stepwise from 0.2 kn to a sharp increase in friction moment. contact area of friction pairs about 1 cm². lubricating compositions were administered in the friction zone on the metal surface for 2km sliding path. during the study recorded the friction coefficient and wear rate. materials used in this study, the basic lubricant oil used was sae 50. investigated lubricant composition additives powders consist of ׃ molybdenum disulfide powder (particle size 4 53µm) at a range of concentration (2 – 8) wt%, soft metal powder, nickel powder,( particle size 4 53µm ) at a range of concentration(2 – 8) wt% and nickel-molybdenum disulfide powder with single-layered coating 4wt% [godloviski, 2008 and rafal, 2011]. measurements coefficient of friction׃ coefficient of friction was measured by using the formula [godloviski, 2008]׃ µ ═ 2t/ p. d (1) where µ ═coefficient of friction t ═moment of friction(n.m). p ═load (n). d ═roller diameter(m). wear rate׃ measurement of linear wear was carried out by the "artificial bases" method by the establishment of an impression on the contacting friction surfaces using the hardness device tcs 1m. the diameters were determined from the impression using a microscope mbs 10. the wear rate was determined by the formula [godloviski, 2008] ׃ al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 113 haidar akram hussien w = 0.004(d2 – d1) / s (2) where w ═ wear rate (µm / km) d1 ═diameter of impression before wearing (mm) d2 ═diameter of impression after wearing (mm) s ═ sliding path (km) results and discussion the tribological properties of lubricating compositions based on the lubricant oil sae 50, filled with powders of various grades of mos2 as well as soft metal(ni) were studied. effect of mos2 powder׃ effect of mos2 powder addition on the tribolorgical characteristics of lubricant oil based on sae 50 was studied at a range of concentration (2 – 8) wt% [holinski, 2003] as shown in figure 2. the lubricating properties of mos2 have been explained by the strong polarization of the sulfur atoms which produce a layer structure, good adhesion to metal surfaces, adhesion between mos2 basal planes, easy sliding of mos2 and the formation of a homogeneous continuous film. the load carrying part of the mos2 film lies only on the asperities of the metal surface. the results can be explained by the fact that mos2, as a solid lubricant helped to form, through the process, a solid lubricant layer helps to reduce friction losses in the relative sliding of solid bodies. it was evident that (2 wt%) mos2 in the lubricant composition is not enough to form a solid lubricating film on the metal surfaces that separates from the rubbing surfaces. however, increasing the amount of mos2 over (6 wt%) results in a thick loose film, deleted in wear action with an increase in friction moment. results also revealed that minimum friction coefficient was obtained at (4 wt%) of mos2 addition . in figure 3 results had revealed that, an addition of (4 wt%) of mos2 powder to lubricant oil based on sae 50 would help to reduce friction losses, i.e. reduce the coefficient of friction to reach 0.095 at the load of 0.4 kn, this related to the formation of a solid protective lubricating film of mos2 on the sliding metals surfaces which increased the contact surface area between the sliding bodies, mos2 powder has the characteristics which are crystal structure, fine particle and large specific surface area. in figure 4 results revealed little influence of mos2 powder adding to the lubricant oil based on sae 50, on the wear rate at these operating conditions [godloviski, 2008 and holinski, 2003]. this is because of little changing in wear rate values. effect of soft metal(ni) powder׃ as already noted, for lubricant compositions as fillers can be used soft powder (anti-friction) of metals nickel, tin, lead, etc.[aurelian, 1989]. effect of ni powder addition on the tribolorgical characteristics of lubricant oil based on sae 50 was studied at a range of concentration (2 – 8) wt% [godloviski, 2008] as shown in figure 5. it was noted that an addition of ni powder to the lubricant oil at a range of 4wt% would help to reduce friction losses, i.e. reduce the coefficient of friction to reach its minimum value under experiment conditions. this related to the formation of thin plastic film of nickel on steel surfaces, that increased the contact surface area. in figure 6 results had revealed that an addition of (4wt%) soft powder (anti-friction) of metals – nickel to the lubricant oil based on sae 50 would help to reduce friction losses, i.e. coefficient of friction reduced from 0.122 for lubricant oil sae 50 without additives at a load of 0.4 kn to 0.116 for the lubricant oil sae 50 with 4wt% addition of ni powder at the same load. in figure 7 results had revealed that an addition of (4wt%) soft powder (anti-friction) of metals – nickel to the lubricant oil based on sae 50 would help to reduce the wear rate under these experiments conditions, i.e. wear rate reduced from 6.5µm/km for lubricant oil sae 50 without additives at a load of 0.4 kn to 3.8 µm/km for the lubricant oil sae 50 with 4wt% addition of ni powder at the same load. this may related to the formation of thin plastic film of nickel on steel surfaces, that increased the contact surface area, then the pair of friction steel – steel gradually in some areas on the sliding al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 114 tribological performance of highly fine nickel-molybdenum disulfide powders additive to lubricant oil surfaces, was replaced by a pair of energetically favorable friction steel – nickel, so wear and friction at the same time significantly reduced. effect of nickel molybdenum disulfide composite powder׃ significantly improve the lubricating effect of the fillers can be pre-modification of their surface, i.e. modifying the layered filler powders by reduction of the particles of powder metal films by chemical method [washida, 2003 and popczyk, 2006]. effect of addition of nickel molybdenum disulfide composite powder, i.e. use of firm powder additives on the basis of molybdenum disulfide which particles are coated with one layer of soft metal(ni), on the tribolorgical characteristics of lubricant oil based on sae 50, was studied as shown in figure 8 and figure 9. it was noted that an addition of (4wt%) nickel molybdenum disulfide composite powder to the lubricant oil would help to reduce friction losses, i.e. the friction coefficient was reduced in (1.5 – 2) times under a load of 0.4 kn(fig.8), the wear rate was lowered to (3 – 3.5) times (figure 9) and load capacity of the friction pair was increased by 1.5 times, by compairing with the case of lubricant oil without additives at the same conditions. since mos2 powder as a filler, reducing the coefficient of friction, and nickel powder the wear rate under the same regimes of friction and lubrication , which should lead to reduce friction and wear. then the formation on the contacting friction surfaces of nickel films abled to express anti-friction and wear effects [godloviski, 2008 and holinski, 2003]. in figure 10 friction surfaces was carried out before and after 20 (km) path of friction in the lubricant oil sae 50 with newly developed nickel molybdenum disulfide composite powder at a load of the working surface of 0.4 (kn). photographing the surfaces was carried out using an electron microscope with an increase of 2,000 times, obtained profilograms and photos were presented in figures 10 – a and b and 11. it was noted the sharply difference between profilograms surface friction for lubricant oil sae 50 without additives (fig.10 a) and with 4wt% nickel molybdenum disulfide composite powder (figure10 b). this may related to the formation of solid lubricant and metallic film on the contacting friction surface, abled to improve tribological properties of the lubricant oil composition. conclusion 1. the experiments observed an increase in the efficiency of the lubricating medium in sliding steelsteel pair with the addition of additives to the lubricant oil sae 50, i.e. addition of molybdenum disulfide powder-coated metal (ni) in comparison with the case of separate administration of the same amounts of molybdenum disulfide powder and soft metal, entered separately. 2. put forward a theoretical concept that the introduction of a lubricating base medium of molybdenum disulfide powder and metal as thin layer coating of molybdenum disulfide powder particles should lead to an increase in anti-friction efficiency and anti-wear performance in comparison with the case of separate administration of the same amounts of molybdenum disulfide powder and soft metal, entered separately. 3. obtained tribological characteristics of composite molybdenum disulfide -metal additives in the lubricant oil with a single layer coating. it was shown that in monolayer nickel coating the friction coefficient may drop about (1.5-2) times, and the wear rate about (3-3.5) times compared with the case of usig the lubricant oil without additives. 4. established for the friction pair steel-steel that the introduction of molybdenum disulfide, nickel and composite additives powders observed optimum lubricating effect on the level of concentration of the additive in the range of 3.5 – 4.5 wt. %. 5. metallization of powders filling lubricant compositions help to solve important issues such as: a reducing the amount of powder fillers. b alignment specific gravity (density) of the powders. 6. use as a filler nickel coated molybdenum disulfide powder leads to the formation of nickel films on the contacting friction surfaces able to express anti-friction and wear effects. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 115 haidar akram hussien references 1. bo zhang, yi xu, bao sen zhang, bin shi xu “tribological performance research of micro powders addictive to lubricant oil. journal, advanced materials research, volume 154-155, pp.220-225, 2010. 2. v.a. godloviski “ivestigation of the tribological properties for lubricant compositions filled with metal”, collection of scientific proceeding of the viii international conference, saint petersburg – russia, 2008. 3. k. washida, y. sasaki ”wear and mechanical properties of sintered copper – composites containing molybdenum disulfide”, paper, industrial technology center, japan, 2003. 4. r. holinski, j. gansheimer “a study of the lubricating mechanism of molybdenum disulfide”. journal, advanced materials research, volume 3, p.145-151. germany 2003. 5. m. popczyk, j. kubisztal, “electrodeposition and thermal treatment of nickel coatings containing molybdenum, ” journal, materials science, № 3, vol. 514, pp.182-185, 2006 6. galda, pawel, rafal. improvement of tribological properties of coating elements by oil pockets creation on sliding surfaces”. journal meccanica, № 3, vol. 46, pp.523-534, 2011, poland. 7. a. budniok, a. lasia ”study of the hydrogen evolution reaction on nickel-based composite coatings containing molybdenum powder”. journal, materials science, vol. 2, pp.43-47, 2007. 8. aurelian c.,” electrodeposition of metal powders”, vol. 3, elsevier scientfic publishing company, amsterdam, oxford, new york, pp. 336, 1989. 9. r.i. taylor, r.c. coy, “improved fuel efficiency by lubricant design: a review”, proc. instn. mech.engrs., vol 214, part j, pp 10-15, 2000. 10. m. hoshi, “reducing friction losses in automobilengines”, tribology int., 17, pp 185-189, 1994. 11. c.m. taylor, “engine tribology”, tribology series, 26, vol. 211, part j, pp 91-106, 1997. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 116 tribological performance of highly fine nickel-molybdenum disulfide powders additive to lubricant oil figure 1 simplified diagram of the friction machine cmt 2 1 bottom (rotating) shaft, 2 upper (stationary) shaft; 3loading device, 4sample, 5 – rider (roller); 6 bath for lubrication [godloviski, 2008] . 2 3 4 5 6 0 .0 0 0 .0 2 0 .0 4 0 .0 6 0 .0 8 0 .1 0 0 .1 2 0 .1 4 2 % m o s 2 4 % m o s 2 6 % m o s 2 8 % m o s 2 µ p x 1 0 2 (n ) figure 2 effect of mos2 powder concentration at various loads on friction coefficient(µ) for lubricant oil composite based on sae 50 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 117 haidar akram hussien 2 3 4 5 6 0.08 0.09 0.10 0.11 0.12 0.13 0.14 oil sae 50 without additive oil sae 50 with 4% mos2 µ px102(n) figure 3 effect of load (p) on friction coefficient (µ) for lubricant oil composite based on sae 50 2 3 4 5 6 4.5 5.0 5.5 6.0 6.5 7.0 7.5 oil sae 50 without additives oil sae 50 with 4% mos2 w, µm/km px102(n) figure 4 effect of load (p) on wear rate (w) for lubricant oil composite based on sae 50 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 118 tribological performance of highly fine nickel-molybdenum disulfide powders additive to lubricant oil 2 3 4 5 6 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 2% ni 4% ni 6% ni 8% ni µ px102(n) figure 5 effect of ni powder concentration at various loads on friction coefficient(µ) for lubricant oil composite based on sae 50 2 3 4 5 6 0.105 0.110 0.115 0.120 0.125 0.130 0.135 0.140 0.145 oil sae 50 without additives oil sae 50 with 4% ni µ px102(n) figure 6 effect of load (p) on friction coefficient (µ) for lubricant oil composite based on sae 50 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 119 haidar akram hussien 2 3 4 5 6 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 oil sae 50 without additives oil sae 50 with 4% ni w, µm/km px102(n) figure 7 effect of load(p) on wear rate(w) for lubricant oil composite based on sae 50 2 3 4 5 6 7 8 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 oil sae 50 without additives oil sae 50 with 4% ni-mos2 µ px102(n) figure 8 effect of load (p) on friction coefficient (µ) for lubricant oil composite based on sae 50 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 120 tribological performance of highly fine nickel-molybdenum disulfide powders additive to lubricant oil 2 3 4 5 6 7 8 1 2 3 4 5 6 7 oil sae 50 without additives oil sae 50 with 4% ni-mos2 w, µm/km px102(n) figure 9 effect of load(p) on wear rate(w) for lubricant oil composite based on sae 50 (a) ( b) figure 10 profilograms surface friction for lubricant oil sae 50 without additives (a) and with 4wt% nickel molybdenum disulfide composite powder (b). al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 121 haidar akram hussien figure 11 surface friction photo for lubricant oil sae 50 with 4wt% nickel molybdenum disulfide composite powder (increasing x 2000). al-qadisiya journal for engineering sciences, vol. 5, no. 2, 111-122, year 2012 122 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٦٤ performance evaluation of al-dewanyia water treatment plant in iraq abstract in order to design and operate an effective water treatment system, a thorough understanding of the process of coagulation-flocculation and filtration is essential in the delivery of water of the greatest clarity and lowest possible turbidity in the finished water. this research outlines the finding of investigation of the treatment plant in al-dewanyia in iraq. performance of al-dewanyia water treatment plant in iraq is an essential parameter to be monitored and evaluated to better understanding of design and operating difficulties in water treatment plants. the conclusions of these evaluations may determine required recommendations and highlight modification requirements for continuous design and operating schemes. the evaluation conducted in this research was carried out by reviewing the engineering design to assure matching of standards and codes. also, physical (turbidity and tss) , and biological, analysis were conducted to investigate water quality. the conclusions drawn from this research outlines the importance of accurate engineering design and need for continuous monitoring and analysis of each unit performance. finished water is not conforming to world health organization (who) standard for drinking water. keywords: water treatment plant , turbidity, who, calriflaculater, filter, water quality محطة معالجة میاه الشرب في مدینة الدیوانیة تقیم أداء الخالصة تطلب أدراك شuامل لعملیuات و مراحuل معالجuة میuاه ی، لتصمیم و تشغیل محطات معالجة میاه الشرب بكفاءة عالیة .مسuموحھأدنuى حuدود إلuىرة ومیاه صالحة للشرب و تقلیل العك أنتاجتلبید و ترشیح لغرض ، الشرب من تخثیر تقیuیم أداء محطuة یعتبuر . یلخص ھذا البحث تقuیم أداء محطuة معالجuة میuاه الشuرب فuي مدینuة الدیوانیuة فuي العuراق معالجة میاه الشرب في مدینة الدیوانیة عامل ضروري و مھم لمراقبة و تقیم و فھم صعوبات التصمیم و التشuغیل ات المعالجة فuي العuراق لھuا نفuس التصuمیم الھیuدرولیكيلمحطات معالجة میاه الشرب في العراق الن معظم محط في ھذا البحuث تuم تقیuیم التصuمیم الھندسuي. التدفق في مقدار فلختتو لكن ) میاه سطحیة(ومصدر المیاه ھو النھر dr.abbas a. al-jeebory assist.prof college of engineering -university of al-qadissiyia dr.ali h. ghawi lecture college of engineering -university of al-qadissiyia عباس علیوي الجبوري. د أستاذ مساعد جامعة القادسیة –كلیة الھندسة علي ھادي غاوي. د مدرس جامعة القادسیة –كلیة الھندسة al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٦٥ و لغرض تقییم نوعیuة المuاء النuاتج مuن المحطuة . لغرض التأكد من مطابقتھ للمحددات التصمیمیة لمحطة المعالجة و مuن أھuم نتuائج ھuذه . فuي مختبuر محطuة المعالجuة و الملوثuات الحیویuة، المuواد الصuلبة العالقuة، یاس العكورةتم ق الدراسة ھو وجوب االھتمام بتصمیم محطuات المعالجuة و المراقبuة المسuتمرة لمراحuل المعالجuة و تحلیuل أداء كuل عuuایر ومحuuددات منظمuuة الصuuحة العالمیuuة لمیuuاه ان نوعیuuة المuuاء النuuاتج ن محطuuة المعالجuuة ال یتوافuuق مuuع م. مرحلuة .الشرب introduction aldewanyia water treatment plant in iraq (dwtp) was built in 1973. the untreated water is pumped from the al-dewanyia river to the dwtp by five large pumps and is then dispatched into flash mixer. the water then flows through a four calriflaculaters (flocculation, and sedimentation tank) and filtered through a sand bed (20 unit) as shown in figure 1. after chlorination, the water is stored in two underground reservoirs (clear well). five booster pumps, connected to the last reservoir, ensure the water supply in the aldewanyia city network. in this study a water treatment plant, dwtp, was investigated from all aspects and considerations including; engineering, chemical, biological, and bacteriological to determine water treatment plants efficiency and produced water quality. this study will define design and operating problems and difficulties for this case study. that will allow for proper revision of these aspects to define the suggested recommendations to be considered in designs and operating conditions. the findings of this research may be applicable for other wtps either under design or under operation. previous literature have recorded water treatment plants difficulties including problems associated with filter operational problems such as air binding and negative head due to algae respiration and filter media cracking. also, the handbook of the water quality prepared by the awwa, 1971 [1] have illustrated other operating considerations required for proper performance such as control needed for chemical additions and analysis. eldib [2] has illustrated in different studies the importance of continuous monitoring and analysis laboratory works to evaluate performance before and after each treatment unit. when online, a periodic review of plant performance is undertaken to ascertain if, or otherwise, the plant works according to prediction. hammer [3] and cairncross [4] both agree that record–keeping and periodic reviews of plant performance are necessary decision tools when the plant requires expansion or when operational problems arise. the purpose of the study is to evaluate the performance of existing water treatment plant in al-dewanyia city with a view to identifying the gabs/ inadequacies (if any) regarding quality of water used and supplied after treatment including performance of all treatment process. it is well-neigh appreciated that the operation of the system mainly suffers due to lack of systematic approach and co-ordination al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٦٦ material and method s 1. experimental work providing cleaner water to the consumers also reduced maintenance demands as less routine flushing is required of the mains reticulation system. the higher turbidity levels previously resulted in sludge build up in the mains which reduced the quality of the water that reached the consumers and also affected the chlorine residual levels throughout the reticulation system. in al-dewanyia in iraq, the dwtp, meeting seasonal water demands, provides water to the city, and some villages around, supplying around 96 000 m3/day serving about 300 000 consumers. the water to the al-dewanyia city comes from the al-dewanyia river (figure 2) source and treatment in the water treatment plant. as it is typical of the rivers of the iraq, the flow is very irregular, having a high flow place in the months of december to april and a low flow in the remain months. the surface water from al-dewanyia river very often contains suspended clay, sand and lime particles, various organic dissolved solids and other materials, which manifest themselves as turbidity, dissolved solids and other chemical parameters. this water has to be treated properly to make it suitable for drinking and domestic use. samples of turbidity were collected from intake and from all wtp’s units where full analysis were carried out in the laboratory of dwtp. analysis were conducted for chemical, physical, bacteriological analysis. all experiments were done and results were determined in accordance to the standard methods (apha) [5]. in order to assess the performance of the water treatment plant in terms of water quality, turbidity measurements were taken between unit water treatment processes during experiments. the outlet measurements were compared to water quality standard values. also in dwtp there is no monitoring system to measure different chemical parameters. water turbidity was measured with the portable turbidimeter hach model 2100p from january 1 th , 2008 to december 31 th , 2008 . this turbidimeter operates on the nephelometric principle of turbidity measurement (scatter light ratio to transmitted light). the measuring range is 0–1000 ntu with an accuracy of +/2% of readings (hach 2004). the calibration of the turbidimeter is based on three samples of standard turbidity (20, 100, 800 ntu). al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٦٧ daily water samples were collected between unit water treatment processes. for highturbidity events, measurements of the inlet turbidity and outlet turbidity were taken at least every fifteen minutes. water samples were taken with a 1.5 l plastic bottle filled in an average of 15 s. the performance of this design has been tested on a 96000 m3/day scale at a demonstration-scale drinking water treatment plant, which was designed to test the various treatment process lines that consist of a combination of unit processes such as coagulation/flocculation, sedimentation, sand-filtration, and chlorination. raw water collected from al-dewanyia river was used as feed water and alum was used as coagulants. al-dewanyia river, with high density of residence located on both sides. figure 1 and table 1 show seasonal characteristics of water quality in al-dewanyia river. as shown in figure 3, target compounds in al-dewanyia river are algae, taste & odor matter, natural organic matter (nom), disinfection by-products (dbps) and micro pollutants. table 2 shows the comparison of water quality criteria between iraq and us.epa. especially, domestic water quality is minimal requirement to meet present regulation, but drinking water treatment process is practically managed to meet the target water quality value which considered the reinforced water quality criteria and target compound concentration in al-dewanyia river. 2. process description in order to design and operation an effective water treatment system, a thorough understanding of the process of coagulation-flocculation and filtration is essential in the delivery of water of the greatest clarity and lowest possible turbidity in the finished water. clarity also aids filter operation by reasonably long filter runs. the aggregation step. a cousin system of the solids contact basin consists of a sedimentation zone inside an annular clarification section. filtration is the final and most important solid-liquid separation step in potable water treatment. the following gives a brief description of all dwtp units components facilities. intake coarse bar screen along with two pipe conduits each of 800 mm diameter collects raw water to a raw water sump of 240 m3 volume. this can maintain a minimum retention time of about 8 minutes at low water level of the canal and up to 13 minutes retention al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٦٨ at high water level. the intake is located about 300 m away from the location of the treatment plant (figure 4). prechlorination a prechlorination dose of about 3.5 mg/l along with 35 mg/l alum dose are added at the distribution chamber inside the treatment plant and directly prior to coagulation process. alum is added as a solution of 10% concentration (figure 5). coagulation and sedimentation the raw water is coagulated continuously with aluminum sulphate in flash mixer tank of 13.3 3 m3 with a retention time of 22 seconds. next, the water flows through the 4 clariflocculator of 38 m diameter (clarifier) with a retention time of 1.5 hr and 14 m diameter of flocculater with a retention time of 18 minutes and arrive to twenty rapid filters. also, surface loading rate of 42 m3/m2/d was maintained (a higher loading rate limit) (figure 6). sand filters twenty filters are used, flow of each is about 83 l/s (eighteen are working and two for washing). surface area of each is 42.5 m2. the rate of filtration was found to be about 235 m3/m2/d, while standard is to be about 120-180 m3/m2/d. sand analysis were conducted on sand samples and it was found that the effective size of the sand is about 1.2 mm, where the standard is 0.45 to 0.55 mm. this shows that sand used inside filters is coarse. also, uniformity coefficient was found to be 2, where standard is 1.75 to 2. this also proves that sand used is a coarse media and out of the standard limits (figure 7) . storage and other facilities the plant contains ground and elevated storage tanks with insufficient capacities, however, this is not the objective of this work, it should be highlighted that proper volume should be maintained for storage capacity. also, the plant was found to contain all auxiliary buildings such as pumping units, sludge tanks, stores, workshop, laboratory and all others. results and discussion the experiments were carried out in the water treatment plants supplying aldewanyia (iraq) from al-dewanyia river. the water is treated with traditional al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٦٩ processes like coagulation flash mixing, flocculation, sedimentation (clariflocculator), filtration and disinfections. turbidity was measured between unit water treatment processes during experiments. table 3 includes turbidities between unit processes. the figures 8 , 9, and 10 present turbidity for samples taken between processes. as we supposed, no reduction and even increase of turbidity were observed after flocculation. higher hydration of flocs after flocculation caused to increase of total suspended particles volume. monthly turbidity measurements are shown in figure 8. the maximum turbidity recorded (raw water) is about 200 ntu (as shown in figure 3) but a lot of rain events were measured. on sunny days, the turbidity was about 60 ntu. the figure 8 shows the water quality of dwtp (turbidity) before and after treatment in summer and winter. as stated on all analyses received since treatment started “this water complies with the recommended guidelines [who] for drinking water quality.” the most important increasing of turbidity were noticed after sedimentation. flocculated particles were not effectively reduced in sedimentation tank. turbidity increased about 30 times. it could be explained by proportionally lower volumetric decrease of fine particles in total suspended solid volume than bigger particles after sedimentation. probably, some big, strongly hydrated flocs characterized by small density settled too slowly to stop in sedimentation tank. such big particles like these should not inflow to the filters, because they block upper pores of sand media (but the big particles are inflow to filter). filtration reduces nephelommetric turbidity from 30 to 50, not guaranteeing lower value than standards. results presented in table 2 show lower removal efficiency of sedimentation and filtration processes predicted base on nephelometric turbidity. the turbidity variations are as represented in figure 11 higher effluent turbidity values were recorded during august 2008, higher effluent turbidity values (≈3540 ntu) were observed during the august 2008. this could be due the increase with regards to consumption for the homes. the experimental work has indicated that turbidity of raw water was in the range of 130-60 ntu, with tss. of 56-82 mg/l. also, the analysis has indicated a total bacterial count of 140 to 11 x 102 with high values in august. algae total count was found to be in the range of 686 to 694 organism/ml, diatoms, green and blue green algal groups were all found. through treatment processes, the turbidity was reduced to about 20 to 30 ntu at the effluent ground water tank. the microscopic investigation of the scum formed on top layers of the coagulation tank shows high concentrations of algae, while chemical analysis shows high concentration of alum. this reflects the need for precise al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٠ determination of alum dosage and application of proper mixing as driven in the engineering evaluation. figure 12 show microscopic of scum in coagulation tanks. the objective of this case study in this research is to outline different operating and design problems found in the treatment plant and to define the conclusions for modifications and considerations. al-dewanyia plant is suffering from a main malfunctioning in the coagulation tanks. figure 13 shows the phenomenon observed where about 30-cm thick scum is accumulated at top of these tanks daily. that requires routine daily removal of this layer. also a similar thickened layer settled at bottom of the coagulation tanks. analysis conducted has indicated that raw water is highly polluted by organic matter, bacteria, and algae. at the intake works, the raw water sump has a large volume yielding about 8 to 13 minutes retention time, while standard is to be about 2 to 5 minutes. the raw water sump was found to have sediments at bottom and full of organic pollution. the pumped raw water to the coagulation tank (flash mixer) with these conditions allows further increase in suspended matters. the laboratory analysis still indicated the existence of organics in the coagulation tank. the study recommended minimization of retention in raw water sump by minimization of volume, to prevent sedimentation, either by recirculation for complete mixing or by dividing the sump into two chambers. since the raw water sump is about 300 m away from the plant site, pre-chlorinating is not a desired solution for bacterial and algal. also, retention time was more than needed in raw water sump, flash mixer , clarifier and flocculater which affected negatively treatment performance. filters were found to have sand out of standards for effective size. it was concluded also that neat design is always recommended. conclusions the conclusions that can be drawn from these engineering and laboratory investigations can be summarized as follows: 1. finished water is not conforming to who standard for drinking water 2. performance of wtp units are not satisfactory 3. rapid sand filters sand should be according to standards. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧١ 4. continuous maintenance and analysis will lead to precise evaluation of plant performance and definition of any required modifications. acknowledgements the authors wish to thank the al-dewanyia water treatment plant staff for accessing to the required data. references [1] handbook of water quality, 1971, awwa, usa. [2] el dib, m. a., 2001. reports on water treatment plants performance evaluation, academy of science and technology, cairo, egypt. [3] hammer j.m. 1975, water and wastewater technology, john wiley & sons, inc, n.y.c., 1975, p. 222-261. [4] cairncross s. 1981. evaluation for village water supply planning, john wiley & sons inc. n.y.c., 1981, p. 2-15 [5] apha. 1992. standard methods for the examination of water and wastewater. 18th ed. american public health association, american waterworks association, and water pollution control federation, baltimore, md. table 1. seasonal characteristics of water quality and limitation of water treatment season water quality pattern limitation 1~3 month nom ↑, mkerq qricpke pqllwvcpvs↑ mixing/coagulation performance decrease 3~6 month algae ↑, tcsvg & qfqr mcvvgr ↑ ph ↑, rgskfwcl chlqrkpg cqpe. ↑ dbps ↑ (chlqrkpg dqsg ipergcsg) mixing/coagulation performance decrease 6~9 month turbidity ↑ alkalinity ↓ filtration bachwashing interval decrease coagulant and ph controller increase al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٢ 9~12 month algae ↑ nom ↑, dbps ↑ dbps ↑ (chlqrkpg dqsg ipergcsg) claim ↑(tcsvg & qfqr mcvvgr) table 2. comparison of water quality criteria between iraq and us.epa items water quality criteria water quality target value us.epa criteria taste & odor sensory evaluation no taste/odor <3ton <3ton geosmin, mib <10ng/l pathogenic microbes giardia 3 log 5 log 5 log cryptosporidium 3.5 log 3 ~ 3.5 log turbidity 5 ntu 0.1ntu 0.1ntu particles 50/ml disinfection by-products (dbps) toc 35% removal 15 ~ 50% removal general items nh4+ 0.5㎎/l 0.5㎎/l fe 0.3㎎/l 0.3㎎/l 0.3㎎/l mn 0.3㎎/l 0.05㎎/l 0.05㎎/l ph 5.8 ~ 8.5 7.5 ~ 8.0 6.5 ~ 8.5 table 3 nephelometric turbidity (average) between each of the unit processes unit process raw water, before coagulation after flush mixing after clariflocculator after rapid filtration turbidity [ntu] 75 70 40 20 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٣ figure 1. al-dewanyia wtp layout ` treatment work distribution work l. l. p cl2 r.s.f . s.g.t h. l. p e.t. -l.l.p.: low lift pump -f.m.: flash mixing & distribution tank -r.s.f.: rapid sand filter -cl2: dosing of chlorine -s.g.t.: storage ground tank -h.l.p.: high lift pump -e.t.: elevated tank collection work al dewanyia river f.m. coagulant clariflocculator cl2 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٤ figure 2. al-dewanyia rivers map al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٥ figure 3. seasonal characteristics of raw water collected from al-dewanyia river s.vn.r.v s.v sec.elevation raw water pump station g.s. groove foot path screens shaft stairs 1:100 l.w.l. h.w .l. ( 5.00 ) ( 6.00 ) 3:2 ( 10.00 ) ( 0.00 ) ( 4.34 ) ventilator motor weir light to station plan 3 :2 3 :2 1500 m m to station s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v s.v n.r.v n.r.v n.r.v n.r.v n.r.v n.r.v n.r.v n.r.v n.r.v n.r.v 4 pipes 800 mm figure 4. shore intake al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٦ figure 5. prechlorination dose figure 6. coagulation and sedimentation al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٥ figure 7. sand filters al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٦ figure 8. monthly turbidity measures from january 2008 to december 2008 figure 9: turbidity variations in treated water after sedimentation tanks al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٧ figure 10. turbidity variations in treated water after filter tanks figure 11: turbidity variations in treated water in 2008 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٨ figure 12. microscopic of scum in coagulation tanks. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٦٧٩ figure 13. the phenomenon observe where about 30-cm thick scum is accumulated at tank nonlinear dynamic analysis of laminated composite plates under in-plane compressive loads dr. husain m. husain professor in civil engineering, university of tekrit dr. nameer a. alwash professor in civil engineering, university of babylon dr. haider k. ammash lecturer. in civil engineering, university of al-qadisyia abstract a nonlinear finite element method is adopted for the large displacement elastic-plastic dynamic analysis of anisotropic plates under in-plane compressive loads. the analysis is based on the twodimensional layered approach with classical and higher order shear deformation theory with five, seven, and nine degrees of freedom per node, nine-node lagrangian isoparametric quadrilateral elements are used for the discretization of the laminated plates. both consistent and lumped mass matrices are used in the present study. damping property is considered by using rayleigh type damping which is linearly related to the mass and the stiffness matrices. newmark integration method is used for solving the dynamic equilibrium equations. the effects of initial imperfection, orthotropy of individual layers, fiber’s orientation angle, type of loading, damping factor, and fiber waviness on the large displacement elastic-plastic dynamic analysis are considered. the conclusion it is shown that the antisymmetric cross-ply laminated plate has a damping rate faster than the symmetric cross-ply laminated plate and if damping is considered and if the response of the plate shows no oscillation about the static deflection position, it means that the damping factor is below the critical damping factor. تأثير الطلاء على مقاومة التآكل لفولاذ متوسط الكربون 2052 لسنة 509-59 ،لثالثا العدد الخامس، المجلد الهندسيه، للعلوم القادسيه مجلة 95 على مقاومة التآكل الكهروكيمائيبعض طرق الحماية تطبيق ck 80عالي الكربونلفوالذ مالك نعمة حواس بشرى رشيد محمد نوال حمودي موسى الكلية التقنية/ المسيب معهد التكنولوجيا / بغداد معهد التكنولوجيا / بغداد الموجز الكربون يــــــــــــــــــــعال الكهروكيميائي لفوالذ التآكلعلى مقاومة بعض طرق الحماية دراسة تأثيرالى هدف البحث ي ) 80 (din ck لغرض اختبار سم (5,1×5,1× 2,0المستخدم بابعاد ) من المعدنعينات تحضيرحيث تم تم استخدام عدد من طرق الحماية منها الطالء الكهربائي حيث تم الطالء بعنصري الكروم والمنغنيز ، التآكل آكل الكهروكيميائي هذه الطرق على معدل الت تاثير وكذلك استخدام المثبطات والحماية الكاثودية من اجل بيان كهربائية الخلية الامرار تيار كهربائي في استخدام طريقة المجهاد الساكن في اختبار التاكل حيث تم تم. للمعدن يمثل المعدن القطب الموجب اما القطب السالب فكان من البالتين عند جهد تم تحديده من خالل امرار تيار اذ بعدها تم ، وأن هذا الجهد تم مقارنته مع جهد المعدن في السلسلة الكهروكيميائية (مفتوحة )دائرةفي الدائرة من خالل التآكل( وايجاد تيار 522-،522اغالق الدائرة وتم امرار التيار عند هذا الجهد مع زيادة مقدارها )+ ل البحث وجدنا ان من خال. التآكلمماسات التقاطع للقطب االنودي والكاثودي وفق طريقة تافل وحساب معدل . جميع هذه الطرق ساهمت في تقليل معدل التآكل وبنسب مختلفة مقارنة بالمعدن األساس ، المثبطات ، الحماية الكاثودية، الطالء الكهربائي ، الفوالذ عالي الكربون التآكل: الكلمات الدالة application of the protective ways on the electro chemical corrosion resistance for high carbon steel ck80 malik nemaa hawaas bushra rasheed mohameed nawal hamody mosa technical college-almusaib institute of technology – baghdad institute of technology baghdad abstract the effect of some protection methods on electrical corrosion resistance of high carbon steel (din ck 80) is studied. electrical coating using chrome and tin elements were implemented on some specimens to show the effect of this element on corrosion behavior نوال حمودي موسىوبشرى رشيد محمد ومالك نعمة حواس 2052لسنة 509-59هندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ال 96 in addition to use inhibitors and cathodic protection for the same purpose. the potential static method used for corrosion test where electrical current flow through electrical open circuit where the metal represent the cation and platinum represent the anion to determine the potential of the metal and compared it with the metal potential's in electrochemical series closing the circuit and the current flow by increasing the potential +_100 milvolt through the intersection contacts to the cathodic and anodic electrode in accordance with tafel's method and calculation of corrosion rate. it can be deduced that all methods used contributed in reducing the corrosion rates by different percentages comparing with the base metal . مةالمقد منها وسائط النقل البرية والبحرية وانابيب نقل البترول وهياكل نظرًا ألهمية الفوالذ في التطبيقات الهندسية ومته الضعيفة للتآكل في معظم األوساط لذا اهتمت العديد من الحلقات البحثية امقبسبب و البنايات والجسور او ئييصيب المعدن نتيجة تفاعل كيميا التآكلان بدراسة مقاومته للتآكل وحساب كلفة الحماية منه. بسبب التفاعل المباشر بين الفلز او أالكيميائي ينش التآكلكهروكيميائي مع الوسط الموجود فيه، حيث ان ينشأ بسبب تيار كهربائي يتعرض له المعدن نتيجة الكهروكيميائي التآكلالسبيكة مع البيئة المتصلة بها اما عدة أشكال يعتمد على ظروف الوسط ومن التآكلكل ناتج عن تفاعل كلفاني ويتخذ آتسليط جهد خارجي او ت كل آتعرية، تالكل آ، تالحبيبية كل مابين الحدودآكل تقصف الهايدروجين، تآكل إجهادي، تآكل منتظم، تآأنواعه ت في الوسط السائل منها التآكلعوامل تؤثر على معدل العديد من الهناك .كل ميكانيكي آت و شرتقالكل آنقري، ت وكذلك معدل جريان الوسط المغمور به ودرجة حرارة الوسط وكذلك وجود عناصر السبك في (ph)مضية االح من العوامل المهمة ففي حالة كون (ph)إن الحامضية (.alstom ،0222( )dieter ،0222)المعدن يستمر بينما الوسط التآكلأي ان التآكلزيد من معدل يفان مقدار الهيدروجين ةالوسط قليل (ph) حامضية أبطئ. فيه التآكلالقاعدي )قلوي( فيكون طبقة من المعدن هو ترسيب الذي ي المعدن ءطالال ومنها التآكلطرق الحماية من دراسة في البحث الحالي تم المراد الطالء به من خالل عملية تحليل كهربائي لمحلول يحتوي على ملح المعدن الذائب وبذلك يكتسب سطح والطالء الكهربائي من الطرق . (lowen، 5591) السبيكة األساس مواصفات وخواص المعدن المطلي به الشائعة االستعمال وطورت لتصبح تقنية ممتازة وال تعتمد على تفاعل كيميائي بين معدن الطالء والسبيكة لعملية الطالء الكهربائي. تتلخص (metal surface preparation)األساس لذا يجب تهيئة سطح المعدن ن المراد طالءه كاثود يغمر في سائل مكون من محلول أمالح عملية الطالء بالترسيب الكهربائي بجعل المعد معدن الطالء الذي يدعى اليكتروليت مع إضافة بعض المواد المساعدة التي قد تكون عوامل مضافة تعمل على تحسين خواص طبقة الطالء او مواد محفزة للتفاعل، ويربط المعدن المراد ترسيبه باالنود في خلية الطالء في هذه الدراسة تم استعمال مادة الكروم والقصدير لغرض طالء الفوالذ العالي الكربون ومعرفة مدى الكهربائي. وتناولت العديد من .(praveen ،0222( )5515،دليل الطالء الكهربائي للمعادن ) التآكلتأثيره على معدل lowen heim (lowen ،8721)قام الباحث البحوث دراسة تاثير عملية الطالء على مقاومة التاكل اذ وكذلك واستخدم طريقة المجهاد الساكن في االختبار. بدراسة تاثير الطالء الكهربائي على مقاومة التآكل للفوالذ عالي الكربونلفوالذ كيمائي على مقاومة التآكل الكهروبعض طرق الحماية تطبيق 80 ck 2052لسنة 509-59مجلة القادسيه للعلوم الهندسيه، المجلد الخامس، العدد الثالث، 97 تاثير الطالء بمادة الزنك على مقاومة التآكل النابيب متناهية في praveen (praveen ،0222)درس الصغر . هي مادة كيمياويـة تضـاف إلـى السـوائل فتمنـع التآكـل علـى جـدار الوعـاء الـذي استخدام المثبطات التي وكذلك تم يحتويهــا ألنهــا تحــول دون حــدوث التفــاعالت الكيمياويــة عنــد األنــود أو الكــاثود أو كليهمــا وتوقــف بالتــالي مفعــول ف مـانع التفاعـل الكيميـاوي إلـى السـوائل خاليا التآكل كما أنها تترك طبقـة خفيفـة عازلـة علـى جـدار الوعـاء. يضـا ) بتركيـــــز معـــــين دوريـــــا ويمكـــــن اســـــتعمال هـــــذا األســـــلوب فـــــي بـــــار الحفـــــر والمراجـــــل ومنظومـــــات الميـــــاه nervana،0282) قـام العديـد مـن البـاحثين اذ وهنالك العديد من الدراسات والحلقات البحثيـه فـي هـذا المجـال nervana ( nervana،0282 )بتناول موضوع استخدام المثبطات ودورها في تقليل التآكل ومنهم الباحث حيث استخدم سـليكات الصـوديوم كمـادة مثبطـة فـي حـالتي السـكون و الحركـة مختبـرا معـدل التآكـل بطريقـة الـوزن aramideوالباحــث . تحريــك الوســط اعطــى نتــائج افضــل المفقــود وقــد اوجــد ضــرورة اضــافة المثبطــات دوريــا وان (aramide،2005) الــذي درس اســتخدام نتريــت الصــوديوم بتراكيــز مختلفــة علــى تآكــل الفــوالذ فــي مــاء البحــر .%4باستخدام طريقة الوزن المفقود ووجد ان افضل تركيز هو نسبة طريقـة الحمايـة الكاثوديـة حيـث أن التآكـل فـي المعـادن يقـع فـي المنطقـة األنوديـة نتيجـة تفريـ التيـار اسـتخدام اما مـن الواضـح أذن أن .الكهربائي منها إلى الوسط من حولها مـع بقـاء المنطقـة الكاثوديـة سـليمة وخاليـة مـن التآكـل حقيــق ذلــك باســتخدام تيــار كهربــائي مــن عمليــة التآكــل تتوقــف إذا أصــبحت جميــع أجــزاء المعــدن كاثوديــة ويمكــن ت مصــدر خــارجي يســري باتجــاه مضــاد لتيــار خاليــا التآكــل وبكثافــة كافيــة لتجعــل مــن ســطح المعــدن بأكملــه كــاثود يســتقيل التيــار الكهربــائي مــن البيئــة التــي حولــه بــدل أن يفرغــه إليهــا ومــن هنــا جــاء اصــطالح الحمايــة الكاثوديــة ( 8شكل ) ديةوهناك اساليب للحماية الكاثو sacrificial anodesمنظومات الحماية باستخدام أقطاب التضحية -أ impressed currentمنظومات الحماية باستخدام التيار القسري -ب الجانب العملي :ويتضمن الجانب العملي ما يلي (metal selection)اختيار المعدن ومن اجل التعرف والمستخدم في اختبار جومني لقياس الصالدة (din ck80)الكاربون ) عاليتم اختيار فوالذ وان spectrometerم إجراء عملية التحليل للمعدن باستخدام جهاز مطياف تعلى التركيب الكيمياوي للمعدن . 8الجدول التحليل الكيميائي للمعادن مبين في تصنيع عينات االختبار كانت عينة الكل نوع من المعدن وفق بطاقة تسلسل تشغيلي وان أبعاد التآ اختبارتم تصنيع عدد من عينات .سم (2,0× 5,1× 5,1)هي (astmg71-30) وفق المواصفه القياسيه لالختبار نوال حمودي موسىوبشرى رشيد محمد ومالك نعمة حواس 2052لسنة 509-59هندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ال 98 تصنيف العينات والذي يبين تصنيف 0الجدول بعد االنتهاء من عملية تصنيع العينات تم تصنيفها الى مجاميع كما مبين في عينات االختبار. الفحوصات واالختبارات فحص البنية المجهرية تحضير العينات للفحص ألمجهري وتضمن: -أ .مع استعمال الماء µm 5222-822-122-422-012-582تنعيم العينات بورق التنعيم -5 وبحجم .al2o3عملية الصقل باستخدام قماش صقل مع مساعد صقل هو اوكسيد االلمنيوم -0 . 2,0µmحبيبي % 88نتريك + ال% حامض 0ستخدم محلول النيتال ): تم اجراء المعاملة المحلولية باالمعاملة المحلولية -0 كحول اثيلي( . :التالي 0رقم الشكل تصوير البنية المجهرية بواسطة المجهر الضوئي وان صور البنية المجهرية مبينة في -4 عملية الطالء 0 الجدولمن (b,c)على مجاميع العينات بالرمز ( nervana،2010) اجريت عملية الطالء الكهربائي وتضمنت عملية الطالء المراحل التالية: ا بين ـــــــــــــبوزن يتراوح م (na2co3)محلول قاعدي يتكون من كربونات الصوديوم بتنظيف العينات أ غرام (41-02) بينى بوزن يتراوح ما (na3po4.h2o)وتراي صوديوم فوسفيت غرام /لتر ( 02-42) داخل خلية غرام /لتر (51-5,1)ين ـــــا بــبوزن يتراوح م (naoh)وهيدروكسيد الصوديوم /لتر كهروكيميائية حيث تمثل العينة قطب الكاثود اما قطب االنود فمصنوع من الفوالذ المقاوم للصدأ (stainless steel) فولت وذلك إلزالة الدهون والمتعلقات العضوية من سطح 6باستعمال فولتية العينة. القاعدي. الغسل بالماء البارد عن طريق الغمر بالماء إليقاف التفاعل للمحلول ب زالة ما تبقى من دقيقة ال 51% لمدة 51تغطيس العينات في محلول مخفف من حامض الهيدروكلوريك ت المحلول القاعدي وتهيئة السطح لعملية الطالء. .ب الغسل بالماء لنفس الغرض في المرحلة ث تهيئة الخلية ج عالي الكربونلفوالذ كيمائي على مقاومة التآكل الكهروبعض طرق الحماية تطبيق 80 ck 2052لسنة 509-59مجلة القادسيه للعلوم الهندسيه، المجلد الخامس، العدد الثالث، 99 ( سم ويحتوي على قطبين مصنوعة 02×02×02تتكون خلية الطالء من حوض على شكل مكعب ابعاده ) من الرصاص حيث يتم ربط العينة المراد طالئها بالقطب السالب اما القطب الموجب فيربط بمجهز القدرة ( 2.1. حيث تضاف محاليل الطالء داخل علبة موجود فيها ماء ذو حجم اقل من )(dc)للتيار المستمر على تعتمد النصف لتر ويسخن عند درجة حرارة وفترة زمنيةلتر إلذابة المحاليل في الماء وبعد ذلك يكمل محلول الطالء لكل عينة. 3 جدولكما مبينة في وفق ظروف الطالء المبنية و الكروم تمت عملية الطالء بعنصر القصدير ح ة المحلول المطلوب لعملية الطالءئتهي 12غرام /لتر وهيدروكسيد الصوديوم 522يتكون المحلول الخاص بالطالء بالقصدير من كلوريد القصدير -5 غرام /لتر512و سيانيد الصوديوم غرام /لتر غرام /لتر حامض 5و كروميك الامض ــغرام /لتر ح012يتكون المحلول الخاص بالطالء بالكروم من -0 .( على التوالي5%-80في عملية الطالء )رصاص ، انتيمون( )%ان األقطاب المستخدمة ، كبريتيك ال اختبار التآكل -تهيئة المحلول المائي : -أ غـــرام مـــن ملـــح كلوريـــد 01تـــم تهيئـــة الوســـط المـــائي الـــذي اســـتخدم فـــي االختبـــار وهـــو مـــاء البحـــر المتكـــون مـــن وقـد وجـد (ph meter)بواسـطة (ph)قياس نسـبة الحامضـية . تمغرام من الماء المقطر 5222الصوديوم مع .6.8إنها تساوي كيميائي تأكل كهرو تـــم اســـتخدام طريقـــة المجهـــاد الســـاكن ) تآكـــل كهروكيميـــاوي( : حيـــث تضـــمنت إمـــرار تيـــار كهربـــائي فـــي خليـــة وتتكون من: 3 شكلكهروكيميائية قطب موجب يمثل العينة المراد اختبارها . -5 قطــب ســالب يمثــل القطــب الــذي تتجمــع عنــده االلكترونــات التــي تحــررت مــن قطــب االنــود وقــد اســتخدم -0 عنصر البالتين كقطب في هذه الخلية. ( 5الذي تم تحضيره مختبريا كما في الفقرة ) محلول اليكتروليتي هو ماء البحر -0 مصدر للتيار الكهربائي. -4 يتم إمرار تيـار كهربـائي فـي دائـرة مفتوحـة عنـد جهـد يـتم تحديـده حسـب موقـع المعـدن فـي السلسـلة الكهروكيميائيـة ملي فولت عن الجهد الـذي تـم تحديـده وان حـدوث تغييـر فـي 522± وبعدها يتم غلق الدائرة ويمرر التيار بجهد د وتطبيق طريقة تافل في حساب معدل التاكل . الجهد يشير الى ان التاكل حدث ويتم قياس التيار عند هذا الجه .0جدول في a,b, cطبق هذا االختبار على عينات المجموعة نوال حمودي موسىوبشرى رشيد محمد ومالك نعمة حواس 2052لسنة 509-59هندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ال 100 الحماية الكاثودية -ب )قطـب التضـحية( كـان مـن الزنـك حيـث انـه يقـع فـوق الحديـد تم جعـل العينـة كقطـب كـاثود امـا قطـب االنـود a,b,cبطريقــة مماثلــة مــع عينــات dبالسلســلة الكهروكيميائيــة واجــري اختبــار التآكــل علــى عينــات المجموعــة . التآكللبيان دور هذه الطريقة على معدل بوجود مثبط التآكلاختبار -ج وتــم قيــاس الحامضــية 4الجدددول تــم اعــداد كميــة اخــرى مــن مــاء البحــر واضــيف لهــا االمــالح المبينــة فــي واجري االختبار بنفس الطريقة التـي اجريـت علـى ° .08عند درجة حرارة 6.1للمحلول الجديد فوجد انها تساوي التآكـلر المثبط على معـدل لبيان دو eوطبق هذا االختبار على عينات المجموعة a,b,cعينات من مجموعة . 4الجدول وان تراكيز المثبط مبين في النتائج يبين نتائج 4الشكل ، كيميائي الكهرو التآكلبعد عملية a,b,cللعينات التآكلصور يبين 3 الشكل كيميائي للفوالذ ومعدل الكهرو التآكليبين نتائج 5الجدول كيميائي للفوالذ الكربوني، الكهرو التآكلاختبار .التآكل ة النتائج مناقش عاليالذي اجري على الفوالذ الكهروكيميائي التآكلبعد اختبار عليها من النتائج التي تم الحصول جموعة ملعينات ال التآكلوجد أن معدل 4 الشكلو 3 الشكلفي التآكلوصور 5الجدول الكربون المبين في (b) جموعة ملعينات ال التآكلاعلى من معدل المطلية بالقصدير((a وعينات المجموعة(c ) المطلية بالكروم أستخدام الطالء وأن القصدير والكروم التي تم استخدامها ومن األمور التي تتخذ للحد من تأكل المعدن هو كونهما يقعان فوق الفوالذ في كاثود() ) أنود( والفوالذ سلك كقطب سالبسلوكها كأقطاب بسببء كعناصر طال أن ماء البحر هو وسط حامضي جيد التوصيل للكهربائية يتحلل الى ايونات . السلسلة الكهروكيميائية المعدن على القطب الموجب فيتحلل الى ، الهايدروجين الموجبة وأيونات األوكسجين السالبة والذائبة في الماء حد مع ايونات األوكسجين السالبة في المحلول االلكتروليتي مكونة اكاسيد المعدن ايونات المعدن الموجبة التي تت من خالل تفاعلها نودان اضافة المثبطات ساهمت في تقليل التفاعل الحاصل في قطب اال ، التآكلالتي تمثل مع األيونات المتحررة منه وتحرير كمية من ايونات الهيدروجين التي تذهب لقطب الكاثود متحدة مع الوكسجين ( وهذا يتفق مع 5القيمة المتعادلة )( الى phالمتجمع مما يساهم في تعادل حامضية الوسط ووصول ال) اما عينات المجموعة .التآكلفي تقليل معدل بطات المثالذي درس دور afolabi (afolabi ،2009)الباحث d ( اما 5الجدول الذي استخدم االلمينيوم كقطب موجب ، فقد وجد ان معدل التآكل للقطب عالي )كما في عالي الكربونلفوالذ كيمائي على مقاومة التآكل الكهروبعض طرق الحماية تطبيق 80 ck 2052لسنة 509-59مجلة القادسيه للعلوم الهندسيه، المجلد الخامس، العدد الثالث، 101 ( كون المعدن سلك كقطب كاثود 4شكل ) التآكلللمعدن االساس فقد قل وهذا ما بينته صور التآكلمعدل اما الحماية الكاثودية التي تمت سلك قطب مضحي وهذا ما اكدته اساليب الحماية الكاثودية . مواأللومينيو ( فقد وجد ارتفاع في معدل التآكل مما يشير الى dباستخدام قطب مضحي) البالتين( والمتمثلة بالمجموعة) والمتمثل بالمعدن المطلوب حمايته وهو االسلوب تجمع االليكترونات حوله وعدم سريانها الى قطب االنود .المتبع في معظم اساليب الحماية الكاثودية وهذا ما اكدته معظم البحوث والدراسات في هذا المجال االستنتاجات العناصر المطلي بها يتم اختيارها وفق موقعها في السلسلة الكهرو كيميائية كونها تسلك اقطاب موجبة -5 . التآكلهرو كيميائية تساهم في المحافظة على المعدن االصلي من في الخلية الك التآكلاعتمد مقدار التحسن على تيار وقد التآكلساهمت العناصر المطلي بها في تحسين مقاومة -0 .الذي تم الحصول عليه حيث وجد أن عنصر الكروم اعطى مقاومة افضل من عنصر القصدير بمقارنة بالمعدن االساس . التآكلساهم المثبط المستخدم في تقليل معدل -0 المصدددددادر alstom bosch (2000), “corrosion of carbon steel” , keyto metals steel. afolabi samuel(2007), "synergistic inhibition of potassium chromate and sodium nitrite on mild steel". leonardo electronics journal of practices and technologies 11, p.143-145. aramide fatai olufemi (2009), "corrosion inhibitors of aisi/sae steel in a marine environment", leonardo journal of sciences 15, , p.47-52. dieter landolt (2007), “corrosion and surface chemistry of metals”, epfl press, italy. lowen heim f.a (1978), "electroplating ", mc graw-hill , new york . 9-، المعهد المتخصص للصناعات الهندسية ، دائرة التعامل ( 9191)دليل الطالء الكهربائي للمعادن ، بغداد. 991-19الكيمياوي ، ص: nervana a. abd alameer (2010), " studying the effect of sodium silicate as inhibitor on the corrosion rate of carbon steel" f.t.t. scientific international conference in najaf . praveen, b. m., venkatesha, t. v. arthoba naik, y. and prashantha, k. (2007), "corrosion studies of carbon nanotubes–zn composite coating" surface & coatings technology vol.201,pp 58365842. نوال حمودي موسىوبشرى رشيد محمد ومالك نعمة حواس 2052لسنة 509-59هندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ال 102 التحليل الكيميائي للمعدن المستخدم 8جدول يبين تصنيف العينات حسب المجاميع 0جدول حالة العينة رمز العينة a عينات فوالذ عالي الكاربون من المعدن األساس b مطلية بالقصديرعينات فوالذ عالي الكاربون c عينات فوالذ عالي الكاربون مطلية بالكروم d عينات فوالذ عالي الكاربون بأستخدام المثبط e عينات فوالذ عالي الكاربون باستخدام الحماية الكاثودية يبين ظروف عملية الطالء الخاصة لكل عنصر 3جدول العنصر )دقيقة( الزمن (0)امبير/سم التياركثافة )مئوية( درجة الحرارة )فولت( الفولتية (sn)القصدير 5 01 52 6 (cr)كروم 5 5 01 6 يبين انواع وتراكيز االمالح المستخدمة كمثبط 4جدول (mlكليسيرين ) مولبيد الصوديوم )ملغم( ثالثي فوسفات الصوديوم )ملغم( (mlايثانول ) 10 80 80 5 يبين نتائج اختبار التآكل للفوالذ عالي الكربون بمختلف ظروف الحماية 5جدول corrosion rate v (mv) i (µa/cm2) specimen sample 4.532 -642.3 10.3 a 2.552 -606.2 5.8 b 3.124 -398.5 7.1 c 30.932 -1094.4 70.3 d 1.364 -688.8 3.1 e c mn p s ni cr si mo cu v العنصر % فوالذ عالي الكربون dinck80 2,8 2,680 2,25 4 2,224 2,204 2,580 2,214 2,200 2,220 عالي الكربونلفوالذ كيمائي على مقاومة التآكل الكهروبعض طرق الحماية تطبيق 80 ck 2052لسنة 509-59مجلة القادسيه للعلوم الهندسيه، المجلد الخامس، العدد الثالث، 103 .يمثل اسلوب الحماية الكاثودية 8كل ش .40xصور البنية المجهرية للفوالذ العالي الكربون بقوة تكبير 0شكل يوضح الخلية الكهروكيميائية 3شكل نوال حمودي موسىوبشرى رشيد محمد ومالك نعمة حواس 2052لسنة 509-59هندسيه، المجلد الخامس، العدد الثالث، مجلة القادسيه للعلوم ال 104 بطرق حماية مختلفةكيميائي للفوالذ عالي الكربون صور التآكل الكهرو 3شكل مايكرون( 022)قوة تكبير عالي الكربونلفوالذ كيمائي على مقاومة التآكل الكهروبعض طرق الحماية تطبيق 80 ck 2052لسنة 509-59مجلة القادسيه للعلوم الهندسيه، المجلد الخامس، العدد الثالث، 105 كيميائي للفوالذ الكربوني نتائج اختبار التآكل الكهرو 4شكل al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain saadoon awad mohammed abbas saleh hassan muhanad dheyaa hashim al mustansriyha university al mustansriyha university al qadisiya university engineering college engineering college engineering college saadoon_groupvet@yahoo.com abbasaltaee10@yahoo.com muhanadhashim@gmail.com abstract the method in this paper depends on transmitting and receiving the sub image by hiding it inside envelope image (steganography process), using wavelet domain. this method depends on hiding sub-image inside the details information (high resolution) of the covered image after taking the discrete wavelet transformation applied on a covered image. the proposed method for hiding and transmitting the sub image inside the cover image is done by shrinking its values in order to accommodate high resolution details of the discrete wavelet transform of the cover image, after this process is a accomplished, it must rearrange the shrieked sub image information by coding rows and columns positions for hiding inside the high resolution details of the wavelet domain of the cover image. taking the inverse wavelet transform for the new cover image included with the hide information of the sub image information (transmitting steganography process). here the restore operation of the cover image is ready for sending process at any transmission port. the proposed method for receiving the cover image is done by taking the new covered image and applying wavelet transform again to get the details information that are included the coded information of the transmitted sub image. then by encoding for the receiving high details information of the wavelet transform and re arrangement for both row and column as mentioned above but in inverse way, this will lead to the original shrinked sub image. applying stretching process (dshrinking) on a gated sub image, the sub image will get at the end of this step. finally, calculate the mean square error in tables to calculate error rate between different sub images that hided in the cover image and compute the error rate values when calculated according to restore the cover image and compare the result. error rate is less than or equal to .003 when calculated using the cover image and the restore version of the cover image, when hiding different sub images inside it. keywords: discrete wavelet transforms (dwt), inverse discrete wavelet transforms (idwt), mallat algorithm (low and high frequency details), image steganography, image shrinking, image de shrinking, proposed transmission algorithm, proposed reception algorithm, and mat lab instruction sets. المویجي اعتمادا على التحویل تحویل تقنیه الأخفاء الصورة الفرعیه بأستخدام المنفصلالمویجي سعدون عواد محمد عباس صالح حسن مهند ضیاء هاشم الجامعه المستنصریه جامعه القادسیه الجامعه المستنصریه دسه كلیه الهندسه كلیه الهندسه كلیه الهن mailto:saadoon_groupvet@yahoo.com mailto:abbasaltaee10@yahoo.com mailto:muhanadhashim@gmail.com wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 167 وجزــــــــــــمال ( عیه الموجودة داخل مظروف الصورة أرسال و أستالم الصورة الفر مد علىالبحث یعتاالسلوب المستخدم في هذة الطریقه تمكننا من أخفاء الصورة . تقنیة المحول المویجيوذلك باستخدام )عملیه أخفاء المعلومات لصورة اعلىالصورة المخبئه بعد أستخدام المحول المویجي ) ه عالیه دق( یه في داخل تفصیالت معلومات الفرع .المغلفه من أجل أستیعاب تفاصیل تحویل سال الصورة الفرعیه تتم عن طریق تصغیر حجمهاالطریقه المقترحه ألر من الضروري أجراء اعادة ترتیب ،هذة العملیهأتمامبعد. المویجات المنفصله ذات الدقه العالیه لغالف الصورة لمواقع الصفوف و االعمدة آلخفائها داخل مجال معلومات الصورة الفرعیه المنكمشه عن طریق الترمیز ومن ثم أخذ معكوس تحویل المویجات لصورة الغالف ،المویجات ذات التفاصیل عالیه الدقه لصورة الغالف هنا عملیه االستعادة ،) أرسال عملیه أخفاء المعلومات ( لتي تضم المعلومات المخبئه للصورة الفرعیه الجدیدة وا . كون جاهزة لالرسال من خالل اي منفذ أرسال لصورة الغالف ت مرة وأستعمال تقنیة المحول المویجيةستالم صورة الغالف تتم بأخذ صورة الغالف الجدیدالطریقه المقترحه لأل أجراء و ب، الموجودة في المعلومات المشفرة للصورة الفرعیه المرسله المعلومات التفصیلیه أخرى للحصول على المستلمه و أعادة الترتیب للصفوف و االعمدة كما سبق العالیةالدقهمعلومات المحول المویجي ذاتفك ترمیز ل و بأجراء عملیه .الصورة الفرعیة االصلیه المنكمشةالحصول علىوالتي تؤدي الى، و لكن بشكل عكسي الحصول علي الصورة تیجة فك الترمیز یمكن األنالمعلومات الحاصلة نعلى) االنكماش عكس( التمدد .نهایه هذة الخطوة الفرعیة أخیرا یمكننا حساب متوسط مربع الخطأ على شكل جداول ألجل حساب معدل الخطأ بین مختلف الصور الفرعیه و المخبئه في غالف الصورة و حساب معدل قیم الخطأ عند حساب صورة الغالف المستعادة و مقارنه العدید واعادتها ضمن)المظروف(الصورة المغلفة عند أخذ ٠.٠٣كون اقل من معدل الخطأ هنا سی.نتائجلا .من الصور الفرعیة الواجب أخفائها 1. introdution 1.1. discrete wavelet transforms (dwt): dwt is applied on a discrete time signal x (t) and then the coefficients after transform are categorized in two types, smooth (scaling) coefficients (approximated signal itself) and details coefficients. in which the energy of signal is partitioned in time and scale (2), and the equation of dwt as in the following: the coefficient in this wavelet expansion is called dwt of the g(t). these wavelet coefficients completely describe the original signal and can be used in away similar to fourier series (fs) coefficients for analysis, description, approximation, and filtering. if the wavelet system is orthogonal, these coefficients can be calculated by inner products. the dwt is similar to a fs, but in many ways is much more flexible and informative. unlike a fs it can be used directly noperiodic transient signals with excellent results (1). saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012168 1.2. daubechies wavelet filter coefficient: a particular set of wavelet is specified by a particular set of number, called wavelet filter coefficients. here will largely restrict to wavelet filter in a class includes members ranging from highly localized to highly smooth (2). the most simple and localized member, often called daub4, has only four coefficients, c0, c1, c2, and c3. these coefficients will be selected as the element of transformation matrix or multi resolution analysis matrix (mra matrix) used to compute the wavelet coefficients for the image. multiresolution algorithm process less image data by selecting the relevant details that are necessary to perform a particular recognition task (11). the energy of the image is distributed after applying dwt in four bands related to quadrature mirror filter form (qmf). these four bands represent by low information that represent approximately the original image itself with scale version of it, and three bands represented the vertical, horizontal and diagonal edges. these three bands of details are represent the energy concentrated region, thus in order to obtain another details information (next vertical, horizontal and diagonal edges) it must be taken from the low information at the first scale and so on (apply dwt in the form of mra), (4). by considering wavelets as a class of function, which are well suited for the multi scale analysis of an image. loosely said, a multi scale analysis consist of analyzing the image at several scales where low scales nothing but the main contours of the image, and the higher scale contain only the finer details of the image (1)(2)(11). consider the following transformation matrix acting on a column vector of data to its right in equation (10-a); the first row generates one component of the convolved with the filter coefficients c0, c1, c2, and c3. likewise are the third, fifth, and other odd rows. if the even rows followed this pattern, offset by one, then the matrix would be circulate, that, an ordinary convolution that could be down by fast fourier transform (fft) method. instead of convolution with c0, c1, c2, and c3, however, the even rows perform a different convolution with c3, -c2, c1, and -c0. the action of matrix the overall is thus to perform a tow related convolution, then to decimate each of them by half and interleave the remaining half (15) (13). it is useful to think of the filter c0, c1, c2, and c3 as being a smoothing filter, call it h, smoothing like a moving average of four point. then because of the minus signs, the filter c3, -c2, c1, and -c0 call it g, is not a smoothing filter. (in signal processing contexts, h and g are called (qmf),(5). for such a characterization to be useful, it may be possible to reconstruct the original data vector of length n from its n⁄2 smooth or scomponents and its n⁄2 detail or dcomponents. requiring the matrix in equation (10.b) to be orthogonal, so that it’s inverse is just the transposed matrix. one can see immediately the matrix in equation (10.b) is inverse to matrix in equation (10.a) if and if these two equations hold: if additionally it require the approximation of order two, then two addition relations are required: equation (2) and (3) are equation for 4unknown c0, c1, c2, and c3 first recognized and solved by daubechies, the unique solution (up to a left-right reversal) is: wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 169 (9) where, the wavelet coefficient for convolution in dwt domain is as in equation (10.a) and the coefficient for convolution in the idwt as in the equation (10.b). 1.3. two dimension (2-dim) dwt implementation using mallat algorithm: 1.3.1. algorithm: like the fft, the dwt is a fast, linear operation that operates on a data vector whose length is integer power of two. also like the fft, the wavelet transform is invertible. the dwt consists of applying a wavelet coefficient matrix hierarchically. first to the full data vector of length n, then to the “smooth” vector of length n/2, then to the “smoothsmooth” vector of length n/4 and so on until only a trivial number of “smooth……. smooth” component (usually 2) remain the procedure is sometimes called a pyramidal algorithm(4)(5)(11), for obvious reasons. the output of the dwt consists of these remaining components and all the “details” components that were accumulated along the way, the diagram show in the figure (1). if the length of data were a higher power of two, there would be more stages of applying equation (10.a) (or any other wavelet coefficients) and permuting. the end point will always be a vector with to s’s and the hierarchy d’s. d’s, d’s etc. notes that once d’s are generated, they simply propagate through to all subsequence stages. a value d, of any level is termed a ‘wavelet coefficient’ of the saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012170 original data vector, the final value should strictly be called ‘fatherfunction coefficients’ although the term ”wavelet coefficients” is often used loosely for both d’s and final s’s the full procedure is a composition of orthogonal linear operation, the whole dwt is itself an orthogonal linear operation, to invert the dwt, one simply reverses the procedure, starting the smallest level of the hierarchy and working (in above diagram) from right to left, inverse discrete wavelet transforms (idwt),(5)(7). the inverse matrix (10.b) is of course used instead of the matrix (1.a). in two dimensions, the wavelet representation can be computed with a pyramidal algorithm similar to the one dimension algorithm described above. the two dimensional wt can be seen as a one dimensional wavelet transform along the x and y axes, (11). it can be shown that a two dimensional wt can be computed with a separable extension of the one dimensional decomposition algorithm. at each step the decomposed image represented by into a low resolution image and three details image , and . the details images are obtained by applying the low pass and/or high pass filters (qmf) along rows and columns. thus represents vertical details information to the original image , represents horizontal details information to the image , and represents the high frequencies to the to the original . , a block diagram in figure 2 (a) illustrates this algorithm (4)(6). firstly, convolve the rows of image with one dimensional filter, retain every other row, convolving the columns of the resulting signals with another one dimensional filter and retain every other column. the one dimensional reconstruction algorithm described clearly in pyramidal algorithm can also be extended to two dimensions (idwt). at each step the image is reconstructed from , , and this algorithm illustrated in figure 2 (b). add a column of zero, convolve of the rows with a one dimensional filter, add arrow of zero between each row of the resulting image, and convolve the columns with another one dimensional filter (10). figure (3) represents mallat representation of the details image information through wt at depth three. a block diagram in figure 2 (a) illustrates this algorithm by convolving the rows of image with one dimensional filter, retain every other row, convolving the columns of the resulting signals with another one dimensional filter and retain every other column. the one dimensional reconstruction algorithm described clearly in pyramidal algorithm can also be extended to two dimensions (idwt). at each step the image is reconstructed from , , and this algorithm illustrated in figure 2 (b). secondly, add a column of zero, convolve of the rows with a one dimensional filter, add arrow of zero between each row of the resulting image, and convolve the columns with another one dimensional filter (10)(11). figure 3 represents mallat representation of the details image information through wt at depth three. 1.3.2. orthogonal wavelet energy distribution: in 2-dim dwt the energy of orthogonal wt is distribution in the details coefficient. because at each scale of the wt there are approximated image and three details image, these three details represent the energy loot from original image in vertical, horizontal, and diagonal position (8). thus, at each scale the details information (h, v, and d) are stolen from the image original then from smooth (approximated) information at that scale. different algorithm for recognition is attempted by different researcher to design an algorithm using this distributed energy. all these algorithms are not leading to optimum recognition, because it depends on different local energy features(histogram feature) and it’s difficult to find a standard features for different texture image(non-gaussian and non-stationary image)(4)(11). 1.4. image shrinking: region growing and shrinking methods segment the image into region by operating principally in the rcbased image space. some of the techniques used are local, in which small wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 171 areas of the image are processed at a time; others are global, with the entire image considered during processing. methods that can combine local and global techniques, such us split and merge, are referred to as state space techniques and use graph structures to represent the regions and their boundaries (3)(9). various split and merge algorithm have been described, but they all are most effective when heuristics applicable to the domain under consideration can be applied. this will give a starting point for the initial split. in general, the split and merge technique proceeds as follows: 1define a homogeneity test. this involves defining a homogeneity measure, which may incorporate brightness, color, texture, or other applicationspecific information, and determining a criterion the region must meet to pass the homogeneity test. 2split the image into equally sized regions. 3calculate the homogeneity measure for region. if the homogeneity test is passed for a region, then a merge is attempted with its neighbor(s). if the criterion is not met, the region is split. continue this process until all regions pass the homogeneity test (3) (10). there are many variations of algorithm. for example, starting out at the global level, it considers the entire image as our initial region, and then follows an algorithm similar to the preceding algorithm, but without any region merging (6). algorithms based on splitting only are called (multiresolution algorithms splitting). this mergeonly approach will be quite similar, with the differences apparent only in computation time. parameter choice, such as the minimum block size all allowed for splitting, will heavily influence the computation burden as well as the resolution available in the result (9). the userdefined homogeneity test is largely application dependent, but the general idea is to look for features that will be similar within an object and different from the surrounding objects. in the simplest case it might use gray level as our feature of interest. homogeneity test required the graylevel variance within a region to be less than some threshold. gray-level variance can define in two set of equations as shown in the next page. 2. the proposed aproach of image stegannography in wavelet domain image steganography in a simple meaning as explained previously is trying to hide active wanted image inside a cover image in a specific manner that doesn’t change the viewing of cover image to everyone. now, apply image in a certain region of wavelet space of a cover image in a some studying protocol that doesn’t effect on reconstructed output in the last previous section, the results of zero equalized hh algorithm proved that this region of wavelet space contain doesn’t affect hardly on the reconstructed image therefore, try to hide the active wanted image in the hh resolution in wavelet space image. making statistical study on the data point inside hh resolution, it find the band of data is very small and limited in a very narrow band, therefore the first problem that it must solve it is trying to make matching between the data point inside hh resolution and the data point of active wanted image. 2.1. proposed algorithm of image steganography: a block diagram of a generic image steganography system is illustrated in figure (4), here, figure 4 represents the image steganography that takes two sides of work first, is transmission side second for reception, and this algorithm are explain on the next page in steps. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012172 2.2. proposed transmission algorithm: input: active wanted image. output: the cover image. step 1: start. step 2: prepare cover image with size n*n result as shown in figure 7 (a). step 3: prepare active wanted image with size (n/2*n/2) at maximum as shown in figure 7 (b). step 4: take the two dimensional discrete wavelet transform (2d dwt) using specific wavelet filter (daub 4) of the cover image shown in figure 7 (a). step 5: apply zero equalized algorithms on h.h region of the wavelet space as shown in figure 7 (c). step 6: apply proposed shrinking method as in figure 5 on active wanted data point shown in figure 7 (b) into every narrow band to match the original data inside h.h region of the wavelet space shown in figure 7 (d). step 7: replace empty h.h region of the wavelet spaces by the image generated from the previous step in the figure 7 (d). step 8: rearrangement the new form of hh region of the wavelet spaces using the proposed protocol of distribution explained in details in figures 6 (a) and (b), and shown in details in fgures 7 (d), (e) and (f) respectively. step 9: apply 2-d idwt on the wavelet space of the same (ll, lh, hl) resolution and updated h.h resolution as shown in the figure 8 (a) and (b) respectively. step 10: transmit the resulted image. step 11: end. 2.3. proposed reception algorithm: input: cover image. output: the original image. step 1: start. step 2: receive the work image of the proposed transmission algorithm in final step shown in figure 8 (b), which contains active wanted image inside it. step 3: taking 2d-dwt of the working image using specific wavelet filter (daub4) as shown in figures 8 (b) and (a). step 4: separate the image resulted in h.h region as single image as shown in figure 11 (b). step 5: appling the same protocol, which is used in the transmission algorithm but in a reverse direction in order to restore active wanted shrinked image as shown in figures 10 (a) and (b), and in details steps of figures 11 (c), and (d) respectively. step 6: apply d-shrinking (stretching) algorithm as in figure 9 on image of previous step, which shown in figure 11 (d) in order to restore the original active wanted image as it shown in figure 11 (e). step 7: view the result active wanted image as shown in figure 11 (e). step 8: end 3. discussion 3.1 transmission region: this section dedicated for applying the previous proposed algorithm of image steganography using wavelet domain on a test image of size (256*256) as a cover image and also four different images of size (128*128) as active wanted images. implementation of the proposed method is take place in two regions (transmission and reception). the result from the previous implementation is a single modified image of original cover image and the success of our proposed work is get the higher degree of similarity between the modified wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 173 and the original cover image. evaluation the degree of similarity using nmse parameters, and all values of nmse resulted from hiding (butterfly, brittney, boy, and man) in barbara image are listed in table 1 bellow: 3.2. reception region: the image stretching expand the band of data in histogram of the image to fit the full band (i.e. 0255) of colors therefore the contract between colors of image are increased. finally the resulted active wanted image must be similar to the original one. the success of this method must be offers high degree of similarity between the resulted active wanted image and the original one. all the results of nmse values resulted from comparing between resulted and original version of active wanted image are listed in table 2 bellow: 4. conclusion in this method, the calculation of error is calculated by choosing different types of original cover images and also different types of active wanted images, and the calculation of nmse is less than or equal to 0.03. this method adopts here active domain for hiding active wanted sub images, named wavelet domain. in this domain the reliability and the wide area (high frequency region) of the wavelet domain represent the main effect for hiding the shrinking sub image information inside the wavelet domain after rearrangement the shrinking sub image information. wavelet transform domain is active domain, because the speed transformation with no error happened or loss in information after taking the inverse wavelet transform. the inverse transformation after hiding information on it, will lead to original hided sub image with no any loss or deform happened on the information of sub image. but it can see that the error rate is related for removing some high frequencies details of the wavelet transform and exchanging it with the sub image information only. still wavelet domain is the best regard to other domains, related to the four band of it that can give wide area for study the information after taking the wavelet transformation. references daubechies, i., “ten lectures on wavelets” society for industrial and applied mathematical, philadelphia, pennsylvania 1992. 1daubechies, i., “what do wavelet come from: personal point of view,” proceeding of the ieee, vol.84, no.4, pp. 510-513, april 1996. 2gonzales, rc, and wants, p, digital image processing" addison – wesley publishing company 1992. 3mallat, s.g, "a theory for mult iresolutio signal decomposition: they wavelet representation, "ieee transaction on pattern recognition and machine intelligence.vol. 11 no. 7, pp.67-693, july 1989. 4mallat, s.g,"multifrequency channel decomposition of image and wavelet model. ieee transaction on pattern analysis and machine intelligence. vol. 11. no. 7, pp. 23912411, 1989. 5mallat, s.g, "wavelet for a vision" proceeding of ieee vol.84. no. 4, pp.6046140, april 1996. 6nikolaj, h., and mladen, v., “wavelet and time frequency analysis” proceeding of ieee vol.84. no.4, pp.523-540, april 1996. 7riol, o., and vetterli, m., “wavelets and signal processing,” signal processing magazine ieee, vol.8, no.4, pp.14-38, october 1991. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012174 8scott, e., umbaugh,” computer vision and image processing a practical approach using cvip tools” copy right by prentice hall ptr, 1998. 9starck, j.l., murtagh, f., bijaoui, a., “image processing and data analysis: the multiscale approach” cambridge university press, 1998. 10waiel, a., murib, “image recognition using wavelet transform”, m.sc., thesis, university of baghdad, elect. eng. dept. 1998. table 1 nmse of the barbara image, after hiding butterfly, brittney, boy, and man sub images. image name butterfly brittney boy man nmse of barbara image 0.0291 0.036 0.0126 0.0114 table 2 nmse of the restore barbara image, after hiding butterfly, brittney, boy, and man sub images. image name butterfly brittney boy man nmse of restore barbara image 0.0241 0.0121 0.0111 0.0220 figure 1 represents the convolution steps of one dimension vector with discrete wavelet coefficients. figure 2 represents in (a) the decomposition schemes of the discrete wavelet transform, (b) the reconstruction schemes of the inverse discrete wavelet transform. note that * refer to convolution, represents down sampling by two represents up sampling by two, and represents up sampling by two. wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 175 figure 3 mallet representation of the details image information through wt at depth three; where l refer to low or smooth information, while d refer to details information. figure 4 overview of image steganography system (sub image inside image). saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012176 figure 5 proposed algorithm of shrinking method on action sub image (v), using mat lab instructions. where, v is the original matrix size of sub image equivalent to 128 *128 . wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 177 figure 6(a) proposed transmission algorithm for distributing h.h data of sub image x in row direction after shrinking in figure (5), using mat lab instructions. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012178 figure 6(b) proposed transmission algorithm for distributing h.h data of sub image m in column direction after distributed in raw wise direction, using mat lab instructions. wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 179 figure 7 represents the proposed transmission algorithm of the stego-image in steps. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012180 figure 8 represents the final covered image after taking 2d idwt. wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 181 figure 9 proposed algorithm of the d-shrinking method (stretching process method) for wanted image v after invert arrangement in figures (10.a), and (10.b), using mat lab instructions. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012182 figure10(a) proposed reverse protocol for redistributed h.h data x, using key to original shrink sub-image at raw direction, using mat lab instructions wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 183 figure 10(b) represent proposed reverse protocol for redistributed h.h data h, at raw/column directions to original shrink sub-image v. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012184 figure 11 represent the proposed reception algorithm in steps for getting active wanted image. al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 280 modeling of two different types of wind turbines dr. rafid m. hannun lecturer/ mechanical eng. dept., college of engineering, thi-qar university email: eng_rafid005@yahoo.com abstract there are many kinds of wind mills and turbines. in this study, practical rig models of two turbines were manufactured at nassiriya city (31.036 o n, 46.21 o e) to compare their work with other related properties and fundamentals. the first is vertical axis wind turbine called savonius rotor (srotor) with dimensions (1500*500*8) mm, the second is horizontal axis wind turbine has a components of plastic blade, steel bearing, steel base, steel shaft, bearings and pointed blade, the plastic blades erected on steel support of length 210 mm. theoretical analysis of turbines motion were presented in wide manner of explanation. the readings of the two turbines were done in 2 nd , 3 rd , 8 th march and 2 nd , 4 th april , 2011for many parameters of motion, angular velocity, linear velocity, kinetic energy, air mass flow rate and mechanical power. the results of wind velocity were compared with metriological data in nassiriya city. the maximum amount of power was 4.65 watt calculated for horizontal axis turbine. fluent and gambit codes were used to prove the validity of this study. it was concluded that the horizontal axis turbine is more efficient than the vertical one, which is in good agreement with literature. keywords: wind, turbine, mills, wind energy, wind power, savonius-rotor عنــــفــتين ريحــــيتين مختلـــفـــتينة ـــذجــمـــن قسم الهندسة الميكانيكية -جامعة ذي قار -رافد معلك حنون/ كلية الهندسة الباحث م.د. وجزالم الريحية. في هذه الدراسة، تم تصنيع نموذجين عمليين من عنفات ز توجد عدة انواع من طواحين الهواء وال ( وذلك كرنيشدرجة شرق خط 13.63درجة شمال خط االستواء، 13..13عنفات الريحية في مدينة الناصرية )ز ال مقارنة عملية لعملهما والخواص واالساسيات االخرى فيهما. كان النموذج االول لعنفة ريحية عمودية المحور ألجراء عنفة الريحية افقية ز ملم ، أما الثانية فكانت من نوع ال (8*500*1500)تي تسمى بدوامة سافونيوس بأبعادوال وزعانف المحور والتي تتكون من زعنفة بالستيكية ومحمل حديدي وقاعدة حديدية ومحور حديدي ومثبتات للمحامل عنفة بشكل واضح ز ياضي نظري لحركة الملم. تم تقديم تحليل ر .63بالستيكية ثبتت على محور حديدي بطول نيسان من عام 1، 6آذار و 8، 1، 6 لألياموواسع. اخذت القراءات لعدة ايام تم ابراز بعضها في هذا البحث ولعدة خواص من خواص الحركة كالسرعة الزاوية والسرعة الخطية والطاقة الحركية ومعدل الجريان الكتلي 6.33 التي تم الحصول عليها لسرعة الرياح مع بيانات الرصد الجوي تمت مقارنة النتائج ية.للهواء والقدرة الميكانيك mailto:eng_rafid005@yahoo.com dr. rafid m. hannun 281 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 استخدم برنامج عنفة االفقية.ز واط لل4.65واالنواء الجوية في مدينة الناصرية. اقصى قدرة تم الحصول عليها هي fluent و gambit .فأ عنفة االفقية هي اكز استنتاج ان الم تكذلك لبرهنة وجودية الدراسة مع المقاييس العلمية مع أدبيات الموضوع السابقة. من العمودية وذلك كان متوافقا nomenclature symbol definition a cross sectional area of air cylinder (m 2 ) p c the dimensionless power coefficient eq. equation fig. figure ke kinetic energy of wind mill (m 2 /s 2 )  ke the change in kinetic energy of wind mill (m 2 /s 2 ) l the length of air cylinder (m) v the speed of the wind (m/sec) t time interval (sec) p wind power (watt) r radius of the rotor (m) m mass of the air (kg) air m the change of air mass (kg)  the ratio of down wind velocity to up wind velocity (dimensionless)  the destiny of air (kg/m 3 ) introduction wind energy is a potential source of energy. wind is the motion caused by uneven heating of the earth’s surface by the sun and rotation of the earth. it is generated due to various global phenomena such as, air –temperature difference, associated with different rates of solar heating. since the earth’s surface is made up of land, desert, water and forest areas. the surface absorbs the suns radiation differently. locally, the strong winds are created by sharp temperature difference between the land and the sea (smith, 1989). modern wind turbines are classified as either horizontal axis or vertical axis. a vertical axis turbine has blades that rotate around a vertical axis, and its visual appearance has been likened to an eggbeater. a horizontal axis turbine has blades that rotate around a horizontal axis. horizontal axis turbines are the most common turbines in use (johnson, 2006). (percival et. al., 2009) presented an exploration of a savonius rotor (s-rotor) wind turbine adapted for household/domestic electricity generation. the design process and justification of the new machine was described. a prototype has been built and installed at a selected site. the operational experience of this site testing was also summarized. the power of darrieus type wind turbine considering real air velocity on the wind turbine blade was predicted by (du lian et. al., 2010) that found the local blade reynolds number application increasing the accuracy in the region of higher tip speed ratio that can be applied widely in the wind power industry. (sheldahl, 1981) presented a 2-m-dia darrieus vertical axis wind turbine which was extensively tested in the vought corporation low speed wind tunnel. it was operated to determine if field data corresponds to data obtained in the wind tunnel. it is believed that the accuracy of the wind tunnel test data was verified and thus the credibility of that data base was further established. modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 282 (schultz, 2009) applied a common set of requirements to a variety of potential gearbox designs for a 2.0mwwind turbine and compared the resulting “geared component” weights, gearbox envelope sizes, generator sizes, and generator weights. (stiesdal, 1999) showed many components of wind turbines, the aerodynamics of the wind turbine, the transmission system, the generator and control and safety systems. (decoste et.al., 2007) designed, fabricated and tested a darrieus wind turbine which starts solely from the energy of the wind at dalhousie university. rig fabrication of wind turbines manufacturing of vertical axis wind turbine the major components are aluminum blades, steel support, rotor shaft, four ball bearings and four long bolts. the plate of wind fan is shaped as (s) character to create savonius rotor (s-rotor) wind turbine with dimensions (1500*500*8) mm. this fan is erected at the end of a steel shaft without welding. the steel shaft is fastened on a steel structure by using the ball bearing for top and bottom parts. manufacturing of horizontal axis wind turbine the major components are plastic blades, steel bearings, steel base, steel shaft, bearings and pointed blade. the plastic blades are erected on a steel support of length 210 mm in vertical support by bearings for facilitating motion of blades. so, it is supported on a horizontal steel structure with a shaft of length 325mm at the end. there is the steel edge (120, 150, 10) mm with length 103m m for steering the wind turbine in the direction of wind. all parts are fastened on the steel base and structure. theoretical analysis a typical horizontal axis turbine consists of a rotor with two or more blades attached to machine cabin set on top of a post that is mounted on a foundation block. the machine cabin contains a generator attached to the wind turbine. the rotor blades can rotate in the vertical plane and the machine cabin can rotate in the horizontal plane. the ability of the turbine –generator assembly to rotate around a vertical axis is called the yaw effect. the angle between the rotor blades and the plane of rotation of the rotor blades is the pitch angle. the pitch angle of the rotor blades can be used to control the rotation rate of the rotor blade [(wilson, 1994), (nasuk et. al., 1983), (hanson et. al., 1993) and (masse, 1986)]. figure 5 illustrates a cylinder of air approaching a rotating horizontal axis wind turbine. the cylinder of air shown in figure 5 has the volume lav  (1) where a is the cross –sectional area and  l is the length of cylinder of air. if the density of air air  is approximately constant, the mass of cylinder of air is la air v airair m   (2) suppose the cylinder of air in figure 5 is moving with speed air v directly at the turbine. the air speed air v is the speed of wind. the kinetic energy of the moving air is 2 2 12 2 1 air lva airair v air m air ke   (3) dr. rafid m. hannun 283 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 the length l of the cylinder of air that reaches the wind turbine in a time interval t is t air vl  (4) substituting equation (4) into equation (3) gives t air av airair ke  3 2 1  (5) the rate of arrival of air is the wind power, or 3 2 1 air av airt air ke wind p     (6) wind power is proportional to the cube of wind speed. the area a is the surface area of the circle formed by the rotating tip of the rotor blade. if the rotor blade has radius r, the area is 2 ra  (7) substituting equation (7) into equation (6), the wind power: 32 2 air vr airwind p    (8) equation (8) shows that wind power is proportional to the square of the radius of the fan created by the rotating rotor blade. in this analysis, it is assumed that the wind direction is orthogonal to the plane of rotation of the rotor blade. thin rotor blade is assumed. the gyroscopic couple may affect the wind turbine as a result of change in wind direction. the wind speed is seldom constant; it can vary from still to tornado or hurricane speed. the speed of rotation of the tip of the wind turbine is rw tip v  (9) where w is the angular velocity of the turbine. electrical power output from a wind turbine is a product of the efficiency wind  times the input wind power. the optimum power output is approximately [2]: 32 2 air vr airwindwind p windout p     (10) the efficiency wind  depends on several factors: the efficiency of converting mechanical energy of the rotor blade into electrical energy, the reliability of the wind turbine and the rate of rotation of the rotor blade. modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 284 it is assumed that the kinetic energy of the wind incident on the turbine is converted to rotational energy of the rotor blades. the kinetic energy of the moving air that is extracted for power production is ) 22 ( 2 1 downwind v upwind v air m air ke  (11) the mass of air that is needed to move the rotor blade in a time interval t is tactuateavairair m   (12) where actuate v is the wind velocity that actuates the rotor and a is the cross sectional area shown in figure 1 and figure 5. therefore: 2 downwind v upwind v actuatev   (13) substituting equations (12) and (13) into equation (11) gives t downwind v upwind v downwind v upwind v a airair ke    ) 22 ( 2  (14) the extracted wind power is ) 22 ( 22 1 downwind v upwind v downwind v upwind v a airt air ke extracted p        (15) equation (15) can be written in the simplified form ] 32 1[ 3 4 1 windwindwindupwind av airextracted p   3 2 1 . upwind av airp c  (16) where upwinddownwindwind vv / is the ratio of downwind velocity to upwind velocity, and p c is the dimensionless power coefficient ] 32 1[ 2 1 windwindwindp c   (17) the power coefficient is typically in the range 4.00  p c for actual wind turbines. a theoretical maximum power coefficient is obtained by: dr. rafid m. hannun 285 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 0 wind d extracted dp  (18) for . wind  the physically meaningful solution to eq. (18) is 3 1 max)( wind  (19) substituting equation (19) into equation (17) gives the power coefficient 593.0 27 16 max)( p c (20) equation (20) is the theoretical maximum power coefficient and is called betz’ limit. it is approximately 59.3% of the power in the wind which is the maximum percentage of the wind power that can be extracted (fluent, 2008). in this paper, the values of p c are found by equation (17) to be limited between 0.59 to 0.13 for different readings of turbines. in addition to the horizontal axis wind turbine analysis previously mentioned, the vertical axis differs in projected area where the wind affects it. herein, the area is 50×50 cm and the other parameters are the same. this movement of turbine has starting velocity for continuous movement with any direction. results and discussion: the findings of this paper were accomplished in nassiriya city region (31.036 o n, 46.21 o e). this city has high ranges of wind speed along the year. the readings were recorded at different hours and days with same location by using a laser anemometer. the metrological data of wind speed were taken to compare the results of this study from metrology center in nassiriya. figure 6 shows the angular velocity readings for the two turbines in 8 th march 2011, the vertical turbine has high values for all readings because its diameter is larger than the other, so, its actuated area is larger to increase the rotating torque resulted due to wind force by affected area. the angular velocity readings of turbines for five days of measurements are shown in figure 7. also, as in figure 6 the vertical turbine rig has higher angular velocity values than that for horizontal axis turbine due to the difference in affected area for both turbines. the general curves line equations give that (y=0.166x+34.228) line equation of vertical axis turbine and (y=0.1433x+22.179) for the horizontal axis turbine which was found by using ms. excel operating system programmer. this gives 34.228 rpm as minimum value of the vertical and 22.179 rpm for horizontal one. it is observed that the curves have similar general inclination for all findings of the two turbines which give good validity of readings. the actuated area of the vertical and horizontal axis turbine was 3927 cm 2 , 706.86 cm 2 respectively. therefore, area ratio = this ratio affects the torque, velocity, work and power output of the turbines with the same ratio and the same direction of rotation. these values are less than that predicted before as a result to different types and axes of turbines. the velocity of vertical turbine has a smaller area ratio which gives a modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 286 correct prediction that the horizontal axis turbine is more efficient. this is in good agreement with literatures. figure 8 presentes the upwind and downwind angular velocity findings for the previous measurement days for both wind turbines. it has the same prediction which give an agreement with previous findings of the similar manar curve for higher and lower values. so, it has the same result shown by figure 9 for velocity values for up and downwind. equation (13) is used to find the values of actuated velocity of turbines which explained obviously by figure 10 which intimates with agreement manar values. it has 2.2 m/s as higher velocity value. figure 11 presentes the values of mass flow rate of air calculated by equation 12 that follow the same curves trend for velocity component shown by figure 10. the kinetic energy of the moving air that is extracted for power production is shown by figure 12 which is calculated by equation 11, in addition to the difference in kinetic energy that is calculated by equation 14 for both fans. that curves has the same trend as previous curves of velocity, air mass flow rate etc. because their values is proportional to each other. figure 13 presentes the effeciencies of different wind turbines evaluated by (wilson, 1994) that gives the maximum efficieny is less than 60% for ideal optimum wind turbines. this is as a result to many disadvantages and industrial problems of turbines such as the direction of blades to wind, the effect of earth surface to wind velocity and the power transfer. the mechanical power accumulated by work turbines is dismantled by figure 14. the values of power extracted previously in this figure by calculation of equations 15 or 16. the maximum amount of power is 4.65 watt for the fifth point of horizontal axis turbine. but, the peak lower value is the first point 0.851 watt also for the horizontal turbine. this is another prediction for the horizontal turbine to be efficient and favorable. validity the validity of this study is done by applying (fluent and gambit codes, 2008)on one of turbines (vertical axis wind turbine). figure 1 is drawn schematically in gamblt code with tetrahedral cube (150*100*150)cm used as tunnel in which the turbine play. tetrahedral meshing scheme with 2 interval size is applied to produce 285950 nodes with smoothing and swapping orders. pressure based, implicit, three dimensions, unsteady, first order, green-gauss node based gradient option and moving mesh with y-axis rotation direction. inlet velocity of 2.67m/s in negative z direction (as shown in figure 15) is selected in this iteration because it is the maximum velocity value resulted by rig readings. the angular velocity is 0.85 rad/s (51rpm). three levels of surface planes are chosen in horizontal planes to predict the parameters. the lower one at the end edge of turbine when y=0 (y=y/h=0) as dimensionless scale, the middle plane at y=0.25m (y=0.5) and the upper (the end) was y=0.5m (y=1). figure 15 shows the turbulent kinetic energy of domain affect the blade with different horizontal position heights. the maximum values take place at the mid plane because it lies inside the effect of blade movement with clockwise rotational direction in impulse direction. the kinetic energy is 2.3 to 3.6 m 2 /s 2 in this figure but is 2.355 m 2 /s 2 (per unit mass) calculated by practical measurement. this gives good prediction that the validity of study is perfect since the programme code work with ideal condition differ than the practical conditions. the air pressure impacts the turbine blade area which results a force exerted as shown in figure 16 on the open direction to rotate the blade in clockwise direction. this due to the pressure is low on the other side of vane accumulated the first side which shown in figure 17 for the same previous slides of horizontal planes. the maximum pressure is 9.62 n/m 2 in b of figure 17 and minimum vacuum pressure reachs 19n/m 2 in rear side of blade in all shapes. dr. rafid m. hannun 287 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 this pressure force leads to move blade in velocity dismanteled by figure 18 which gives the same prediction of figure 17. the maximum velocity at the left side of blade to rotate it in clockwise direction (5.23m/s) as shown in b but the minimum near the blade because of the impact and vacuum due to the rotation. the dominated velocity is (2.613.4)m/s which gives good agreement with 2.67m/s (the rig velocity resulted by experimental measurements). the velocities in x and y direction shown in figure 19 and figure 20 that don’t give good prediction of movement since they are perpendicular the air movement direction distinguished by reverse z direction which shown in figure 21 where the maximum value is at b on the ends of blade. the blade velocity for its two sides in z direction drawn by fluent code shown in figure 22 to predict the similarity in shape and velocity value for upper part with lower and front with rear. this values were similar to there in figure 21. these give good validity of this study. conclusions: this practical case study utilized to conclude the following: 1the earth surface affects the results of wind speed and the rotational movement of turbines to be fluctuated readings. therefore, the erection of wind mills requires high blades from the earth level. 2the horizontal axis turbine is efficient than the vertical one (more than 5 depending the area ratio and movement power). 3the rig models is small scale, therefore the power is very small. 4the selection of erection position for wind turbine is very important in increasing the power depend the historical measurements of this position. references: decoste j., smith a., white d., berkvens d. and crawford j., (2007) “self-starting darrieus wind turbine”, design project for mechanical engineering department in dalhousie university. fluent 6.3.26 and gambit code help, (2008). hanson, a.c. and buterfield , c.p., (1993) “aerodynamics of horizontal –axes wind turbines”, journal of fluid mech., 25,115-149. johnson g. l., (2006) “wind energy systems”, jon and willy, usa. lian d., lee j.h. and kim y.c., (2010) “power prediction of darrieus type wind turbine considering real air velocity on the wind turbine blade”, j. of renewable energy. masse, b., (1986) “a localcirculation model for darrieus vertical –axis wind turbines”, j. propulsion power 2, 135-141. nasuk f.l. and azumy a., (1983) “an experimental verification of the local circulation method for a horizontal axis wind turbine”, paper presented at 18 th intersociety energy conversion engineering conference, orlando. percival m.c., leung p.s. and datta p.k., (2009) “the development of a vertical turbine for domestic electricity generation”, journal of wind engineering. modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 288 schultz c.d., (2009) “the effect of gearbox architecture on wind turbine enclosure size”, agma (american gear manufacturers association) technical paper, virginia usa, isbn: 978--1--55589-97--1. sheldahl r.e., (1981) “comparison of field and wind tunnel darrieus wind turbine data”, sandia national laboratories energy report, usa. smith g.a., (1989) “electrical control methods for wind turbines”, winds eng., 13(2), 88-98. stiesdal h., (1999) “the wind turbine components and operation”, an acrobat version of the special issue of the bonus-info company, web: www.bonus.dk. wilson r.e. and spera d., (1994) “aerodynamic behavior of wind turbines in wind turbine technology, foundation concept of wind turbine engineering”, asme press, new york, 215282. figure 1 fabricated rig of savonius rotor (vertical axis wind turbine) http://www.bonus.dk/ dr. rafid m. hannun 289 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 figure 2 pictures of savonius rotor (vertical axis wind turbine) a. front view, b. side view, c. top view, d. rear view modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 290 figure 3 fabricated rig of horizontal axis wind turbine. figure 4 pictures of horizontal axis wind turbine dr. rafid m. hannun 291 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 figure 5 schematic of horizontal wind turbine. figure 6 angular velocity readings for the two turbines on 8 th march, 2011 modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 292 figure 7 angular velocity readings for the two turbines in 2 nd , 3 rd , 8 th march and 2 nd , 4 th april , 2011 figure 8 upwind and downwind angular velocity readings for the two turbines in 2 nd , 3 rd , 8 th march and 2 nd , 4 th april , 2011 dr. rafid m. hannun 293 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 figure 9 upwind and downwind velocity (m/s) readings for the two turbines in 2 nd , 3 rd , 8 th march and 2 nd , 4 th april , 2011 figure 10 actuate velocity (m/s) for the two turbines with different readings days modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 294 figure 11 air mass flow for the two turbines with different readings days figure 12 kinetic energy (m 2 /s 2 ) for the two turbines with different readings days dr. rafid m. hannun 295 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 figure 13 wind turbine efficiencies (wilson, 1994) figure 14 wind power for two turbines with different readings days modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 296 figure 15 turbulent kinetic energy (m 2 /s 2 ) at a. (y=0), b. (y=0.25m), c. (y=0.5m) figure 16 contour of static pressure as shown by fluent in dec 30, 2011 dr. rafid m. hannun 297 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 figure 17 pressure distribution at a. (y=0), b. (y=0.25m), c. (y=0.5m) figure 18 velocity distribution contour at a. (y=0), b. (y=0.25m), c. (y=0.5m) figure 19 x velocity contour at a. (y=0), b. (y=0.25m), c. (y=0.5m) modeling of two different types of wind turbines al-qadisiya journal for engineering sciences, vol. 5, no. 3, 280-298, year 2012 298 figure 20 y velocity contour at a. (y=0), b. (y=0.25m), c. (y=0.5m) figure 21 z velocity contour at a. (y=0), b. (y=0.25m), c. (y=0.5m) figure 22 velocity magnitude curve drawn in dec. 31, 2011 as shown by fluent 7-2-2011.pdf 75 proportional-integral (pid) controller design using genetic algorithm (ga) the selection of the three coefficients of proportional-integral (pid) controllers (ki, kp, and kd) is basically a search problem in a three-dimensional space. this is so because points in the search space correspond to different selections of a pid controller’s three parameters. by choosing different points of parameter space, we can produce, for example, different step responses for a step input. a pid controller can be determined by moving in this search space on trial-and-error basis. the main problem in the selection of the three coefficients is that these coefficients do not readily translate into the desired performance and robustness characteristics that the control system designer has in mind. several rules and methods using root locus and performance indices. the first design uses the integral of time multiplied by absolute error (itae) performance index. hence we select the three pid coefficients (ki, kp, and kd) to minimize the itae performance index, which produces a good transient response to a step input. our paper uses the genetic algorithm (ga). in this method the selection of the three pid coefficients depends on the minimization of the mean squared error (mse), which will produce an excellent transient response to a step input. : pid controller, itae, and genetic algorithm ga. الخالصة ,ki(الثالثة المعامالت kp, kd( ة(pid) ًمشكلة بحثِ في فضاء أساسا ب.مختلفةتُقابلُ النقاطُ في فضاءِ البحثَ .ثالثي األبعاد التكاملي -.استجابة نظام لمدخل دالة معامالتِمِنْ فضاءِ الةمختلف .الخطأَالتجربة وقاعدةِا باالعتماد على دّة قواعد عِ. المعامالتِ ال تُترجمُ معامل اَ.performance indices)و root locus(وطرق اَستعمل مما )itae .()itae(مكاملة مضاعفة زمن الخطأ المطلق . )ga .( .مما )mse(لمعدل مربع الخطأ 76 many industrial processes are controlled using proportional-integral controllers. the popularity of pid controllers can be attributed arty to their forename in a wide rang of operating conditions and partly to their functional which allows engineers to operate them in simple , straightforward manner . to implement such a controller, three parameters must be determined for the given process: proportional gain, integral gain, and derivative gain. the feedback control system shown in will be our tested system that the laplace term (gp(s)) represent the plant transfer function, (gc(s)) the controller transfer function and (h(s)) the feedback transfer function. the input and output laplace term will be r(s) and y(s) respectively. so we can classify the controllers to four types [1][2]: the p-controller is a pure gain (no dynamics) of value kp (i.e. gc(s) = kp) thus we see that the gain kp that we have been varying to generate the desired response, that is , the system characteristic equation is given by: 0)()(1 this controller is used in situations in which satisfactory transient and steady–state responses can be obtained simply by setting a gain in the system, with no dynamic compensation required. this controller increases the system by 1 and is used to improve the steady–state response. the transfer function of the pi controller can be expressed as )( (1) the controller has a pole at the origin and at zero at ki /kp . since the pole is nearer to the origin than is the zero , the controller is phase – lag , and the controller adds a negative angle to the criterion of the root locus ,hence this controller is used to improve the steady-state response of the system , as stated earlier . the open–loop function can be expressed as )()()()()()( (2) and we see that are only two independent parameters to be determined in the design process. we can arbitrarily set k=1 without affecting the generality of the design, the problem is then to determine kp and ki to meet certain steady-state design criteria. the transfer function of the pd controller is )()( (3) thus the pd controller introduces a single zero at s = kp / kd , and it is seen that this controller adds a positive angle to the criterion of the root locus, therefore , the pd controller is a type of 77 phase –lead controller and improves the system transient response . since only a single zero is introduced. the open–loop function can be expressed as: )()()()()()( (4) the design of proportional–plus–integral-plus-derivative (pid) controller is introduced in this section. the pid controller is probably the most commonly used controller in feedback control system. with r(t) the controller input and y(t) the output (according to ) , the pid controller is defined as : )()()( (5) or )( )( )( )( )()()( a block diagram representation of this controller is given in , and the transfer function are shown in .quite often it is not necessary to implement all three terms to meet the design specification for a particular control system. let us consider a single – loop second –order system and determine its response step input a closed – loop feedback control system is shown in the output is: )()( )(1 )( )( 2 (6) utilizing the generalized, we may rewrite this equation as: 22 2 2 )( (7) with a unit step input, we obtain )2( )(( (8) for which the transient output, as obtained from the laplace transform: 78 )sin( 1 1)( (9) where 10,cos,1 12 then transient response of second order system for various values of the damping ratio (ζ) is shown in , the closed-loop roots approach the imaginary axis, and the response becomes oscillatory. the response as a function of time is also shown in for step input. the laplace transform of the unit impulse, where r(s) =1, implies 22 2 2 )( (10) which is t(s) = y(s) /r(s), the transfer function of the closed-loop system. the response for an impulse function input is then sin)( (11) which is simply the derivative of the response to a step input. the impulse response second–order system for several values of the damping ratio. the designer is able to select several alternative performance measures from the response of the system for either a step or impulse input [1][3][4]. standard performance measures are usually defined in terms of the step response system as shown in . the swiftness of the response is measured by the rise time and the peak time . for under damped system with an overshoot, the 0-100% rise time is a useful index. if the system is over damped, then the peak time is not defined, and the 10 – 90 % rise time, is normally used. the similarity with which the actual response matches the step input is measured by the percent overshoot and settling time . the percent overshoot, , is define as: %100*.. (12) for a unit step input , where is the peak value of the time response , and is value of the response normally is the magnitude of the input , but many system have a final value significantly different from the desired input magnitude , for the system with a unit step represented by eq ( 12 ) ,we have = 1. the setting time, , is defined as the time required for the system to settle within a certain percentage of the input amplitude, this band of ± is shown in for the second order system with closed-loop damping constant , with a response described by equ.(11) we seek to determine the time, , for which the response remains within 2 % of the final value. this occurs approximately when 02.0 or 4 therefore we have 4 4 (13) 79 hence we will define the setting time as four time constants (that is , ) of the dominant roots of the characteristic equation . the steady–state error of the system may be measured on the step response of the system as shown in . the transient response of the system may be described in terms of two factors: 1the swiftness of response, as represented by the rise time and the peak time. 2the closeness of the response to the desired response, as represented by the overshoot and settling time. as nature would have it, these are contradictory requirements, and a compromise must be obtained. the explicit relation for and as a function of ζ is: therefore the percent overshoot is or 22 .))/100(( .)/100( (14) increasing emphasis on the mathematical formulation and measurement of control performance can be found in the recent references on automatic control. modern theory assumes that systems engineer can specify quantitatively the required system performance, then a performance index can be calculated or measured and used to the system’s performance. whether the aim is to improve the design of a system or to design a control system performance index must be chosen and measured. a system is considered an optimum control system when the system parameter adjusted so that the index reaches an extremism value, commonly a minimum value performance index, to be useful, must be a number that is always positive or zero, then best system is defined as the system that minimizes this index. a suitable performance index is the integral of the square of the error, ise, which is defined as: 0 2 )( (15) the upper limit t is a finite time chosen somewhat arbitrarily so that the integral approaches a steady – state value. it is usually convenient to choose t as the setting time, ts. another readily instrumented performance criterion is the integral of the knitted of the error iae which is written as 0 )( (16) this index is particularly useful for computer studies. to reduce the contribution of the large initial error to the value of the integral as well as to emphasize errors occurring later in the response, the following index has been proposed: 21/1 80 0 )( (17) the performance index itae provides the best selectivity of the performance index that is, the minimum value of the integral is readily discernible as the system parameters are varied. table(1) illustrates the optimum coefficients of the t(s) based on the itae criterion for a step input [2][5]. a genetic algorithm (ga) is a search technique used in computing to find exact or approximate solutions to optimization and search problems. genetic algorithms are categorized as global search heuristics. genetic algorithms are a particular class of evolutionary algorithms (also known as evolutionary computation) that use techniques inspired by evolutionary biology such as inheritance, mutation, selection, and crossover (also called recombination). genetic algorithms are implemented as a computer simulation in which a population of abstract representations (called chromosomes or the genotype of the genome) of candidate solutions (called individuals, creatures, or phenotypes) to an optimization problem evolves toward better solutions. traditionally, solutions are represented in binary as strings of 0s and 1s, but other encodings are also possible. the evolution usually starts from a population of randomly generated individuals and happens in generations. in each generation, the fitness of every individual in the population is evaluated, multiple individuals are stochastically selected from the current population (based on their fitness), and modified (recombined and possibly randomly mutated) to form a new population. the new population is then used in the next iteration of the algorithm. commonly, the algorithm terminates when either a maximum number of generations has been produced, or a satisfactory fitness level has been reached for the population. if the algorithm has terminated due to a maximum number of generations, a satisfactory solution may or may not have been reached. genetic algorithms find application in bioinformatics, phylogenetics, computational science, engineering, economics, chemistry, manufacturing, mathematics, physics and other fields. a typical genetic algorithm requires two things to be defined: 1a genetic representation of the solution domain, 2a fitness function to evaluate the solution domain. a standard representation of the solution is as an array of bits. arrays of other types and structures can be used in essentially the same way. the main property that makes these genetic representations convenient is that their parts are easily aligned due to their fixed size that facilitates simple crossover operation. variable length representations may also be used, but crossover implementation is more complex in this case. tree-like representations are explored in genetic programming and graph-form representations are explored in evolutionary programming. the fitness function is defined over the genetic representation and measures the quality of the represented solution. the fitness function is always problem dependent. for instance, in the knapsack problem we want to maximize the total value of objects that we can put in a knapsack of some fixed capacity. a representation of a solution might be an array of bits, where each bit represents a different object, and the value of the bit (0 or 1) represents whether or not the object is in the knapsack. not every such representation is valid, as the size of objects may exceed the capacity of the knapsack. the fitness of the solution is the sum of values of all objects in the knapsack if the representation is valid, or 0 otherwise. in some problems, it is hard or even impossible to define the fitness expression; in these cases, interactive genetic algorithms are used. once we have the genetic representation and the fitness function defined, ga proceeds to initialize a population of solutions randomly, then improve it through repetitive application of mutation, crossover, inversion and selection operators [6][7][8]. 81 initially many individual solutions are randomly generated to form an initial population. the population size depends on the nature of the problem, but typically contains several hundreds or thousands of possible solutions. traditionally, the population is generated randomly, covering the entire range of possible solutions (the search space). occasionally, the solutions may be "seeded" in areas where optimal solutions are likely to be found. during each successive generation, a proportion of the existing population is selected to breed a new generation. individual solutions are selected through a fitness-based process, where fitter solutions (as measured by a fitness function) are typically more likely to be selected. certain selection methods rate the fitness of each solution and preferentially select the best solutions. other methods rate only a random sample of the population, as this process may be very time-consuming. most functions are stochastic and designed so that a small proportion of less fit solutions are selected. this helps keep the diversity of the population large, preventing premature convergence on poor solutions. popular and well-studied selection methods include roulette wheel selection and tournament selection. the next step is to generate a second generation population of solutions from those selected through genetic operators: crossover (also called recombination), and/or mutation. for each new solution to be produced, a pair of "parent" solutions is selected for breeding from the pool selected previously. by producing a "child" solution using the above methods of crossover and mutation, a new solution is created which typically shares many of the characteristics of its "parents". new parents are selected for each child, and the process continues until a new population of solutions of appropriate size is generated. these processes ultimately result in the next generation population of chromosomes that is different from the initial generation. generally the average fitness will have increased by this procedure for the population, since only the best organisms from the first generation are selected for breeding, along with a small proportion of less fit solutions, for reasons already mentioned above. this generational process is repeated until a termination condition has been reached. common terminating conditions are: a solution is found that satisfies minimum criteria fixed number of generations reached allocated budget (computation time/money) reached the highest ranking solution’s fitness is reaching or has reached a plateau such that successive iterations no longer produce better results manual inspection combinations of the above 1. choose initial population 2. evaluate the fitness of each individual in the population 3. repeat until termination: (time limit or sufficient fitness achieved) i select best-ranking individuals to reproduce 82 ii breed new generation through crossover and/or mutation (genetic operations) and give birth to offspring iii evaluate the individual fitnesses of the offspring iv replace worst ranked part of population with offspring whenever the itae performance index gets stuck at a local minimum or the convergence rate is relatively slow depending on the damping ratio value ( ), we start the genetic search by finding the optimal pid coefficient ( and ) with the best fitness i.e. the smallest (mse) as the survivor. in other words, the pid coefficient will be the ga chromosomes in which a fitness value is assigned to each chromosome. the fitness value for the j-th chromosome is inversely proportional to the mean squared error 2 , where ( 2 ) is given by r 1k 2 jj 2 j )](y-(k)[d 1 (18) where r is the window size over which the errors will be accumulated; d(k) is the original response; y(k) is the estimated output associated with the j-th estimated chromosome. the survived chromosome will be the optimized pid coefficient that gets us a minimum mse (or optimal solution). in this section, the feedback control system shown in will be tested with different plants represented by the plant transfer function ( ). the optimum controller coefficients ( and ) for the controller transfer function ( ) will be obtained using itae criteria and genetic algorithm (ga). these optimum coefficients will obtained according to a step input and a required settling time ( ) and percentage overshoot ( ). where: 2 (19) and the closed-loop transfer function: )(1 )( )( )( )( (20) consider a temperature controller with a plant transfer function 2)1( 1 )( (21) we desire to obtain an optimum controller coefficients ( and ) using itae performance and genetic algorithm (ga) for a step input, settling time ( )of ( ) and a percentage overshoot ( ) of ( ). 83 using the plant and controller transfer functions (( ) and ( ) represented by equ.(21) and equ.(19) respectively) we have the closed-loop transfer function according to equ.(20) : )1()2()( )( )( 23 2 (22) the optimum coefficients of the characteristic equation for itae are obtained from table (1) as )15.275.1( 3223 (23) we need to select in order to meet the settling time and percentage overshoot requirement. since 22 .))/100(( .)/100( (24) and 4 (25) so we obtain = 0.34 and = 19.552. the value of will be substituted in equ.(23) to get the characteristic equation: )352.7474903.812216.34( 23 (26) by matching equ.(26) with the characteristic equation (denominator) of equ.(22) we obtain 2 + = 34.216, 1 + = 812.903, and = 7474.352 so: = 32.216, = 811.903, and = 7474.352 the overall transfer function according to itae criteria will be: 352.74749.812216.34 352.74749.811216.32 )( )( )( 23 2 (27) shows the original step response and shows the itae step response according to the transfer function obtained in equ.(27). the mean squared error (mse) according to itae optimization equal to: 0.1005 the mean squared error (mse) between the original step response and the obtained one, dedicated previously in equ.(18), is selected to be minimized by the use of ga in order to obtain optimum pid coefficients that give minimum mse. the specifications that were used in ga tuning are: 84 number of generation =100. population size =20. crossover probability =0.8 (simple crossover). mutation probability =0.05 (uniform mutation). shows the ga step response. the obtained pid coefficients according to ga optimization method are: = 32.0283, = 824.6774, and = 7479.1691 that gives a minimum mean squared error equal to: 0.0347 the overall transfer function due to ga optimization is: 1691.74796774.82502683.34 1691.74796774.8240283.32 )( )( )( 23 2 (28) a cassette tape storage device has been designed for mass-storage. it is necessary to control accurately the velocity of the tape. the speed control of the tape drive is represented by the system shown in and its ( ) is: 40040 10 )( 2 (29) the desired settling time ( ) is ( ) and a percentage overshoot ( ) is ( ). using the plant and controller transfer functions (( ) and ( ) represented by equ.(29) and equ.(18) respectively) we have the closed-loop transfer function according to equ.(19) : 10)10400()1040( 101010 )( )( )( 23 2 (30) repeating steps modeled in equ.(22), (23) and equ.(24) we fined that = 0.358 and = 13.97. the value of will be substituted in equ.(22) to get the characteristic equation: )397.2726595.419447.24( 23 (31) by matching equ.(30) with the characteristic equation (denominator) of equ.(31) we obtain: 40 + 10 = 24.447, 400 + 10 = 419.595, and 10 = 2726.397 so: = -1.5553, = 1.972, and = 272.63 the overall transfer function according to itae criteria will be: 397.2726595.419447.24 397.272672.19553.15 )( )( )( 23 2 (32) fig.(9) shows the original step response and fig.(10) shows the itae step response according to the transfer function obtained in equ.(32). the mean squared error (mse) according to itae optimization equal to: 0.3497 85 the specifications that were used in ga tuning are: number of generation =100. population size =20. crossover probability =0.8 (simple crossover). mutation probability =0.05 (uniform mutation). fig.(11) shows the ga step response. the obtained pid coefficients according to ga optimization method are: = -1.0166, = 1.8710, and = 273.8123 that gives a minimum mean squared error equal to: 0.0849 the overall transfer function due to ga optimization is: 1232.2738707.41829.8338 1232.2738707.181662.10 )( )( )( 23 2 (33) fig.(12) and fig.(13) shows a comparison for the obtained step response (original, itae and ga response) in the same figure for the first and second example respectively. one can see from fig.(12) that there is a similarity between the original response (the sold line) and both the itae response (the dash-dot line) and the ga response (the dashed line). also we can observe that there is a great convergence between the original response (the sold line) and ga response (the dashed line) rather than the itae response (the dash-dot line). finally we can conclude from this comparison that the ga optimization method is suitable in some type of plants but in other types the itae optimization criteria may be more effective than the ga method. generally ga optimization method is a very effective, flexible, tenuous and suitable for many complex plants rather than other methods. [1] r. c. dorf, r. h. bishop, “modern control systems” addison-wesley longman, inc, (1998). [2] chi-tsong chen, “analog & digital control system design” state university of new york at stony brook 2005. [3] kilian, “modern control technology, components and systems” 2nd edition 2006. [4] “control system toolbox for use with matlab”, user’s guide, mathworks, inc., version 4.2, 4th printing, 1999. [5] l. c. jain & r. k. jain “hybrid intelligent engineering systems”, world scientific publishing, co. pte. ltd., 1997. [6] k. –f. man, k.-s.tang, s. kwong & w. a. halang., “ genetic algorithm: concepts and design” city univrsity of hong kong, tachee aveneue, kowloon, maito: email: %20k. nan @ ieee. org. (2000). [7] d. e. goldberg, “genetic algorithms in search, optimization, and machine learning,” addisonwesley publishing company, inc, u.s. (1989). [8] coley, d. a. "an introduction to genetic algorithms for scientists and engineers". world scientific publishing, 1999. 86 the optimum coefficients of t(s) based on the itae criterion for a step input. 6524334256 54233245 432234 3223 22 95.345.760.860.625.3 4.35.50.58.2 7.24.31.2 15.275.1 4.1 : feedback control system with a controller, plant and feedback transfer function. ∫ ki kp kd r(t) y(t)+ _ ( a ) + r(s) y(s)+ _ ( b ) + : pid controller 87 : transient response of a second order system for various values of the damping ratio (ζ) : transient response of a second order system as a function of time 88 : step response of a control system. : feedback control system with a controller and a plant transfer function. : the original step response 89 : the itae step response : the ga response 90 : the original step response the itae step response 91 : a comparison for the three responses for the first example 92 : a comparison for the three responses for the second example al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 46 optimum hydraulic design for inverted siphon thulfikar razzak alhusseini university of al-qadisiya /college of engineering department of civil engineering,. abstract in this research, optimum hydraulic design for siphon has been studied depending on the method of optimization (modified hooke and jeeves) with some modifications. some modifications on this method have done. these modifications are: 1modification on the assumed initials base points 2modification on the value of step length 3modification on the value of the reduced step length at each trial. the siphon shapes that used in this study are pipe, square, and rectangular. the materials that used are concrete and steel for designing inverted siphon. a computer program depending on the method of (modified hooke and jeeves) has written for optimum hydraulic design of inverted siphon structure with "quickbasic" language. many examples solved by using this program to make insure the accuracy of it. keywords: optimum, hydraulic, inverted siphon المعكوسالتصميم الهيدروليكي االمثل للسيفون ذوالفقار رزاق الحسيني آلية الهندسة/ جامعة القادسية قسم الهندسة المدنية الخالصة مع modified hooke and (jeeves ( طريقة على في هذا البحث تم دراسة التصميم الهيدروليكي االمثل باالعتماد تعديالت على -1: يمكن تلخيصها لالتي طريقة أل هذه أن تلك التعديالت على.ديالت التي أجريت عليها خالل هذا البحثبعض التع . تعديالت على قيمة الخطوة المخفضة المضافة في آل محاولة-3 تعديالت على قيمة الخطوة -2النقطة االبتدائية المفروضة للتصميم ) modified hooke and jeeves(باالعتماد على طريقة "quickbasic" تم عمل برنامج حاسب بلغة لقد . من دقته وتم تطبيق عدة أمثلة محلولة باستخدام هذا البرنامج للتأآد االمثل للسيفون،الهيدروليكي nomenclature s: the slope of siphon (dimensionless). v: the velocity of the flow through the siphon barrel (m/s). hf : the total head losses which equals to the difference between the upstream and downstream water level (m). b: span of siphon (m). d: height of siphon (m). y: elevation of water (m). zs: cost of construction per unit meter for steel pipe (i.d). zcp: cost of construction per unit meter for concrete pipe (i.d). zcb: cost of construction per unit meter for concrete box (i.d). al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 47 d: diameter of pipe for siphon (m). l: length of the barrel (m). r: hydraulic mean radius of the barrel (m). v: velocity of flow through the barrel (m/s). va : velocity of approach and is often neglected (m/s). f2 : is a coefficient such that the losses of head through the barrel due to surface friction, f1: constant for elbows losses. f2: constant for bend losses r1: depth of scour below water level (m). q: discharge / meter width (m3/m.s). ca: constant for showing irrigation canal (ca=1) or drainage canal (ca=2). q: discharge (m3/sec). l: length of inverted siphon (m). ke: entrance coefficient. ko: outlet coefficient. ks: screen coefficient. kel: elbows coefficient kex: expansion coefficient kcon: contraction coefficient vc: velocity of canal (m/sec) ye: depth of water in canal (m). b::span of box section (m) d:diameter of pipe (m) d:height of box section (m) f:lacey silt factor (m) f1:coefficient of head losses at entry (m) k1:entrance coefficient (m) k2:outlet coefficient (m) kcon:contraction coefficient (m) kex:expansion coefficient (m) l:length of the barrel (m) q:discharge / meter width (m3/m.s) r:hydraulic mean radius of the barrel (m) r1:depth of scour below water level (m) v:velocity of flow through the barrel (m/s) va:velocity of approach and is often neglected (m/s) zcb:cost of construction for concrete box (i.d) zcp:cost of construction for concrete pipe (i.d) zs:cost of construction for steel pipe (id). introduction highways and railroads traversing the land cut across individual watersheds. to allow the flow from each watershed across the embankment, culverts, siphons and aqueducts are used. although these structures simple in appearance, their hydraulic design is no easy matter. the operation of these structures under the various possible discharge conditions presents a somewhat complex problem that cannot be classified either as flow under pressure or as free surface flow. the actual conditions involve both of these concepts. hydraulic structures employed to convey, control, measure and protect the flow of water at various locations in an irrigation and drainage system. there are many different types of structures can be used for these purposes though individually they may be small or large. structures can al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 48 contribute to a large part of the overall capital cost of an irrigation project; hence, a proper design of these facilities is a major factor in making the scheme efficient and keeping capital costs to a minimum. the final design must take into consideration the practices and farming methods in vogue and should endeavor to meet the requirements of the farmer and thereby enlist his cooperation. this will minimize maintenance costs by minimizing mis-use and vandalism. other factors that affect the design and operation of irrigation structures include site conditions, the methods employed for the conveyance of water and the availability of construction materials. only the smaller sizes of structure are amenable to having the design procedure standardized. purpose and description of inverted siphons inverted siphons used to convey canal water by gravity under roads, railroads, other structures, various types of drainage channels, and depressions. a siphon is a closed conduit designed to run full and under pressure (aisenbrey, et al., 1974). the structure should operate without excess head when flowing at design capacity. a-application economics and other considerations determine the feasibility of using a siphon or another type of structure to accomplish the previous objectives. the use of an elevated flume would be an alternative to a siphon crossing a depression, drain channel or another manmade channel. the use of bridge over a canal would be an alternative to a siphon under a road or a railroad. b-advantages and disadvantages of inverted siphons inverted siphons are economical, easily designed and built, and have proven a reliable means of water conveyance. normally, canal erosion at the ends of the siphon is inconsequential if the structures in earth waterways have properly designed and constructed transitions and erosion protection. costs of design, construction, and maintenance are factors that may make an inverted siphon more feasible than another structure that might used for the same purpose. there may be, however, instances where the value of the head required to operate a siphon may justify the use of another structure such as a bridge (aisenbrey, et al., 1974) . an inverted siphon may present a hazard to life, especially in high population density areas. structure components the siphon profile is determined in such a way as to satisfy certain requirements of cover, siphon slopes, bend angles, and submergence of inlet and outlet. siphon cover requirements are (aisenbrey, et al., 1974) : 1) at all, siphons crossing under roads other than farm roads and siphons crossing under railroads, a minimum of (0.91 m) of earth cover should provided. farm roads require only (0.61 m) of earth cover and are frequently ramped using 10 to 1 slopes (10 percent grade) when necessary to provide minimum cover requirements. if roadway ditches exist and extended over the siphon, the minimum distance from the ditch to the top of the pipe should be (0.61 m). 2) at siphons crossing under cross-discharge channels, a minimum of (0.91 m) of earth cover should provided unless studies indicate more cover is required because of projected future retrogressions of the channel. 3) at siphons crossing under an earth canal, a minimum of (0.61 m) of earth cover should provide. 4) at siphons crossing under a lined canal, a minimum of (0.15 m) of earth cover should provide between the canal lining and the top of siphon. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 49 roadway widths and side slopes at road and railroad siphon crossings should match existing roadway widths and side slopes, or as otherwise specified. side slopes should not be steeper than (1-1/2 to 1). siphon slopes should not be steeper than (2 to 1) and should not be flatter than a slope of (0.005). hydraulic design considerations available head, economy, and allowable siphon velocities determine the size of the siphon. thus, it is necessary to assume internal dimensions for the siphon and compute head losses such as entrance, friction, bend, and exit. the sum of all the computed losses should approximate the difference in energy grade elevation between the upstream and downstream ends of the siphon (available head). in general, siphon velocities should range from (1.07 m/s) to (3.05 m/s), depending on available head and economic considerations (aisenbrey, et al., 1974) . the following velocity criteria may use in determining the dimensions of the siphon: 1(1.07 m/s) or less for a relatively short siphon with only earth transitions provided at entrance and exit. 2(1.52 m/s) or less for a relatively short siphon with either a concrete transition or a control structure provided at the inlet and a concrete transition provided at the outlet. 3(3.05 m/s) or less for a relatively long siphon with either a concrete transition or a control structure provided at the inlet and a concrete transition provided at the outlet. where there is reasonable, confidence that a good standard of construction will achieve the upper limit of velocity through a siphon may take as (3 m/s), where doubts exist as to construction quality this figure may be reduced to (2 m/s),(jawad, kanaan, 1983) . to avoid sedimentations, the minimum velocity that considered is (0.6 m/s). for discharges up to about (2.5 m3/s), pipes can be used but for larger discharges a box section is preferred, (jawad, kanaan, 1983) . for future increase in demand, it is usual to design all canal structures for (1.2 q) where q is the design flow during the period of maximum demand. the minimum design flow is usually taken as (0.7 q), blow this value, there is the risk that sedimentation will occur due to low velocities. for drainage structures, the maximum flow taken as (1.5) times the design flow. minimum flow does not apply to drainage structures, (jawad, kanaan, 1983) . the most common materials used for culverts are concrete and corrugated steel. the roughness in both cases usually assumed constant for any flow depth. on hilly terrains where the culvert slope expected to be relatively steep and the flow through the culvert gains considerable energy, corrugated steel pipes offer energy-dissipating advantages. on flat terrains, energy loss through a culvert is undesirable; hence, concrete pipes are more suitable (simon, 1997). for design purposes in iraq, concrete and steel pipes considered with roughness coefficient (n) equal to (0.014) and (0.01) respectively(jawad, kanaan, 1983). drainage structures must checked against piping, uplift pressure, erosion at upstream, downstream, and protected against sulphate attack on concrete. the protection consist of (0.4×0.4×0.2 thick m) concrete blocks over (0.1 m) gravel bedding for length (2×d) of the barrel for upstream. downstream is similar for length (3×d). depth of scour in unlined canal can be calculated from lacey formula and compared with (2×d) and (3×d) (jawad, kanaan, 1983). r1=1.35× (q2/f) 0.33 (1) where: f: lacey silt factor can obtained from table (1) which used for iraq. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 50 ds =1.5×r1depth of flow (2) length of protection = 1.5×ds (3) to ensure inlet submergence the invert of the siphon section should be dropped so that d greater than the elevation of water at the canal with the drop at the siphon entrance with slope (1 to 5 v: h) which generally equal to (0.5 m). so the discharge will divided into 2,3,4,….etc, to satisfy the previous condition, and that means the siphon sections equal to 2,3,4,…etc. reinforced concrete rigid frame box culverts with square or rectangular opening are use up to spans of (4 m). the height of the vent generally does not exceed (3 m). adopting thickness of slab as (100 mm/ meter span) (simon,1997). head losses of inverted siphon total head losses equal to the sum of the friction, entrance, exit, screens, elbows, transitions and bends losses. the minimum overall head loss for inverted siphons is (0.2 m) (jawad, kanaan,.1983) . losses through siphon can calculate by using the following formula (garg, santosh , 1978) : ∆h = conex 22 hh g2 va g2 v ks2f1f r l 2f1f1 ++−⎥⎦ ⎤ ⎢⎣ ⎡ +++×++ (4) a briefly, discussions about these losses can illustrate as follows: friction losses friction losses through the barrels of siphon can calculate by using the following formula. hf = g2 v r l 2f 2 ⎥⎦ ⎤ ⎢⎣ ⎡ × (5) where: f2 = a ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ + r b 1 (6) where the values of a and b for different materials may be taken as given in table (2). entrance and exit losses entrance losses can calculate from the following equation (jawad, kanaan,1983) : he= k1 g v 2 2 (7) where: k1: entrance coefficient, which obtained from the following table. exit losses can calculate from the following equation(5): al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 51 ho= k2 g v 2 2 (8) where: k2: outlet coefficient which taken as 1.0 for most outlets. screen losses losses through screens and trash racks are related the velocity head of the approach flow and the geometry of the rack (spacing, thickness and shape of bars and inclination to the horizontal). screens used at entry and exit on inverted siphons as a safety precaution to prevent children and unauthorized personal from gaining access. the head loss can related to the percentage of waterway area that the bars take up as shown in table (4) below: hs= ks g v 2 2 (9) elbows and bends losses it remains now to consider the effect of elbows and bends, on the discharge of the siphon. the losses in an elbow or a bend in a pipe appear to be due to secondary circulation and to contraction of the flow, which occur, in, and immediately downstream of, the cause of the disturbance. weisbach gives the following formula for the loss of head in elbows(6) . hel = f1 g v 2 2 (10) where: f1 = 0.9457 sin2 2 ϑ +2.047 sin4 2 ϑ (11) according to this theory, if the radius of curvature r does not change, the length ℓb of the bent portion of the pipe, and angle ϑ , have very little effect (if any) on the total loss of head attributable to the bend. the formula was therefore as follows (leliavsky, serrge, 1979). hb = f2 g v 2 2 (12) where: f2 = (0.13 + 0.16 2/7 ⎥⎦ ⎤ ⎢⎣ ⎡ r d ) o90 ϑ (13) d: diameter of pipe. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 52 transitions losses a channel transition may define, as a local change is cross section, which produces a variation in flow from one uniform state to another. in many hydraulic structures the main reason for constricting or fluming the flow at the inlet is to reduce, the costs of construction of the structure and in some cases can provide an expedient device for measurement of discharges in the main body of the structure. it is important that transitions to and from structures is properly designed when head losses are critical. transitions can serve several other functions, namely: 1to minimize canal erosion. 2to increase the seepage path and thereby provide additional safety against piping. 3to retain earth fill at the ends of structures. all transitions may classify as either inlet (contraction) or outlet (expansion) transition. expansion and contraction losses can be finding from the following equations (jawad, 1983): hex = kex ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − g vc g v 2 2 2 2 (for canal structures) (14) hcon = kcon ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − g vc g v 2 2 2 2 (for canal structures) (15) hex = kex ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − g vc g v 2 2 2 2 2.1 (for drainage structures) (16) hcon = kcon ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − g vc g v 2 2 2 2 2.1 (for drainage structures) (17) where: kex & kcon: are the expansion and contraction coefficient respectively, which can obtained from table (5) depending on the discharge values (depending on the reference of [5]). angle of contraction at the upstream is preferred as equal as or less than 27.5o, and the optimum contraction angle is 14o, while the angle of the expansion at the downstream is equal or less than 22.5o (varshney,1972). optimization method for designing the inverted siphon the purpose of optimization is to find the best possible solution among the many potential solutions satisfying the chosen criteria. designers often based their designs on the minimum cost as an objective, safety and serviceability. a general mathematical model of the optimization problem can represent in the following form (2): a certain function (z), called the objective function, al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 53 z = f} xi} i =1, 2… n (18) which is usually the expected benefit (or the involved cost), involves (n) design variable {x}? such function is to be maximized (or minimized) subject to certain equality or inequality constraints in their general forms: gi {xi} = bi i =1, 2, ………, i (19) qi {xj} ≥ bj j =1, 2, ………, j (20) the constraint reflects the design and functional requirements. the vector {x} of the design variables will have optimum values when the objective function reaches its optimum value. objectives functions the objective function (zs) of the present research for steel pipes siphons involves the cost of transportation, cutting, constructions, and filling as (zs = c×d) (raju,1986), (zs: total cost per unit meter, c: constant, d: diameter of siphon). . the following equation estimated by (statistica) program with a regression coefficient of (r = 0.996): zs = 248791.9×d0.469596 (21) in addition, the objective functions for concrete pipe and box siphons shown below. data for this formula obtained from the reference(7) . zcp = 177798.44× d2 (22) zcb = 514500 ( 3 2 3 2 db + ) (23) the following figure shows the relationships between the costs and the dimensions of concrete siphon (pipe and box) and steel siphons, depending on the previous formulas. constraints for the optimization technique the following constraints that considered for the optimizations technique in this research was as follows: 10.005 ≤ s≤ 0.5 20.6 ≤ v ≤ 3.0 3hf ≥ 0.2 4b ≤ 4.0 5d ≤ 3.0 6d ≤ (y+0.5) modefied hooke and jeeves this method dates back to 1961(3) but is nonetheless a very efficient and ingenious procedure. the search consists of a sequence of exploration steps about a base point, which if successful followed by pattern moves. the procedure is as follows: a) choose an initial base point b1 and a step length hj for each variable xj, j = 1, 2… n. the program given later uses a fixed step h for each variable, but the modification indicated can be useful. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 54 b) carry out an exploration about b1. the purpose of this is to acquire knowledge about the local behavior of the function. this knowledge used to find a likely direction for the pattern move by which it hoped to obtain an even greater reduction in the value of the function. the exploration about b1 proceeds as indicated. i) evaluate ƒ (b1). ii) each variable now changed in turn, by adding the step length. thus ƒ (b1 +h1 e1 ) can be calculated where e1 is a unit vector in the direction of the x1-axis. if this reduces the function, replace b1 by (b1 +h1 e1). if not find ƒ (b1 -h1 e1 ) and replace b1–by (b1 -h1 e1 ) if the function–is reduced. if neither step gives a reduction leave b1 unchanged and consider changes in x2, i.e. find ƒ (b1 +h2 e2 ) etc. when it has considered all n variables, a new base point b2 can obtained. iii) if b2 = b1 i.e. no function reduction has been achieved, the exploration is repeated about the same base point b1 but with a reduced step length. reducing the step length(s) to one tenth of its former value appears to be satisfactory in practice. iv) if b2 ≠ b1 make a pattern move. c) pattern moves utilize the information acquired by exploration, and accomplish the function minimization by moving in the direction of the establish "pattern". the procedure is as follows. i) it seems sensible to move further from the base point b2 in the direction b2 – b1 since that move has already led to a reduction in the function value. therefore, the evaluation of the function at the next pattern point can do. p1 = b2 + 2 (b2 – b1) (24) in general: pi = bi + 2 (bi+1 – bi) (25) ii) then continue with exploratory moves about p1 (pi). iii) if the lowest value at step c (ii) is less than the value at the base point b2 (bi+1 in general) then a new base point b3 ( bi+2 ) has been reached. in this case, repeat c (i). otherwise abandon the pattern move from b2 (bi+1) and continue with an exploration about b2 ( bi+1). d) terminate the process when the step length(s) has reduced to a predetermined small value. in this research some modifications on this method has achieved, since this method is not able to move along the constraint and converges on the first point on the constraint that it locates as the solution. with a certain initial point and certain step length, a certain solution has obtained, while with another initial point or another step length another different solution has obtained. these modifications reduce the difference between the two obtained solutions. these modification in this research as follows: 1assume the initial base point within the range of constraints. 2reduce the step length to a lower value such as (0.00001). 3reducing the step length(s) to (1/1.001) of its former value appears to be more satisfactory in practice instead of one tenth at step b (iii). computer program for optimum hydraulic design in this research, the program was writing with "quickbasic" language depending on (modified hook and jeeves) method with some modifications -since (sumt) method cannot be used due to the fractional powers of constrainsto find the optimum hydraulic design for the inverted siphon. many examples applied by using this program to check the accuracy of it. the following example solved without the optimization technique and with the optimization technique by using this program. the input data for this program were:(ca, cs, l, ke, k0, ks, cel, kex, …) x(i): initial dimension for siphon (i=1 for pipe siphon, i= loop from 1 to 2, for box and rectangular siphon). al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 55 h: step length. many examples applied using the program and compared with the design without optimization as follow: the following figure shows a typical section for inverted siphon: the following table (8) shows the dimensions of siphon with variable discharges, constant velocity (0.82 m/s) and variable elevation for the same canal. the following table (9) shows the dimensions of siphon with variable discharges, variable velocity and constant elevation (1.5 m) for the same canal. the following figure (3) shows the relationship between the cost of siphon construction and discharge. references 1. aisenbrey, a.j., hayes, r.b., warren, h.j., winsett, d.l. and young, r.b., (1974), "design of small canal structures ", denver, colorado, u.s.a. 2. alhusseini, thulfikar, r.,(2004), " analysis and evaluation of water supply facilities for alhilla city" , m.sc. thesis, college of engineering, babylon university, iraq. 3. bunday, brian d., (1985), "basic optimisation methods ", school of mathematical sciences, university of bradford, london. 4. garg, santosh kumar, (1978), "irrigation engineering and hydraulic structures ", khanna publishers, delhi, india. 5. jawad, kanaan, a., (1983), "design manual irrigation and drainage ", pencol engineering consultants and state organization for land reclamation, baghdad, iraq. 6. leliavsky, serrge, (1979), " irrigation engineering: syphons, weirs and locks ", chapman and hall ltd, london, new delhi, india. 7. ministry of irrigation, state commission for irrigation at babylon governorate, (2004), annual report. 8. raju, n. krishna, (1986), "advanced reinforced concrete design", cbs publishers and distributors, delhi, india. 9. simon, andrew l., korom, scott f. (1997), "hydraulics", prentice hall, u.s.a. 10. varshney, r.s., gupta, s.c., gupta, r.l., (1972), "theory and design of irrigation structures", roorkee university, india. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 56 table (1): silt factor [5]. region f northern 0.7-1.0 central 0.6 southern 0.5 table (2): values of a and b for different materials [4]. materials of the surface of the barrel a b smooth iron pipe 0.00497 0.025 encrusted pipe 0.00996 0.025 smooth cement plaster 0.00316 0.030 ashlars or brick work 0.00401 0.070 rubble masonry or stone pitching 0.00507 0.250 table (3): entrance coefficient [5]. description k1 for square edged inlet flush with vertical walls 0.5 for rounded inlets, radius r where r/ d ≤ 0.15 0.1 for grooved or socket ended pipes 0.15 for projecting concrete pipes 0.2 for projecting steel pipes 0.85 table (4): loss coefficients for screens and trash racks [5]. bar area/waterway area % 5 10 15 20 25 30 loss coefficient (ks) 0.12 0.25 0.42 0.62 0.86 1.15 table (5): expansion and contraction coefficients siphon section discharge m3/s kex kcon 2.5-5 0.6 0.3 box > 5 0.2 0.1 < 0.5 1.0 0.5 pipe 0.5-2.5 0.7 0.4 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 57 table(6): data for optimum hydraulic design for inverted siphon q(m3/s) vc(m/s) elev. of water(m) length of siphon(m) kent kext ks kelb case 1 4 0.82 1.50 41.3 0.2 0.3 0.2 0.05 case 2 5 1.0 2.0 50 0.2 0.3 0.2 0.05 case 3 10 1.50 2.0 70 0.2 0.3 0.2 0.05 case 4 20 1.50 2.0 70 0.2 0.3 0.2 0.05 table (7): output of the above input data with and without optimization technique. case no. of sections dimension (m) without optimization 1 1.45 x 1.45 1 with optimization 1 1.15 x 1.15 without optimization 1 1.54 x 1.54 2 with optimization 1 1.29 x 1.29 without optimization 1 2.13 x 2.13 3 with optimization 1 1.83 x 1.83 without optimization 2 2.13 x 2.13 4 with optimization 2 1.83 x 1.83 table (8): dimension of siphon and its number of sections for constant velocity. q(m3/s) 4 8 10 12 15 18 20 25 30 y(m) v(m/s) 1. 5 3. 0 3. 75 4. 5 5. 63 6. 75 7. 5 9. 38 11 .3 0. 82 1. 12 × 1. 12 1. 64 × 1. 64 1. 82 × 1. 82 2 × 2 2. 23 × 2. 23 2. 45 × 2. 45 2. 58 × 2. 58 2. 88 × 2. 89 2. 23 × 2. 24 se ct io n n o. 1 1 1 1 1 1 1 1 2 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 58 table (9): dimension of siphon and its number of sections for constant elevation. q(m3/s) 4 8 10 12 15 18 20 25 30 v(m/s) y(m) 0. 82 1. 64 2. 05 2. 46 3. 08 3. 69 4. 10 5. 13 6. 15 1. 50 1. 12 × 1. 12 1. 58 × 1. 58 1. 76 × 1. 77 1. 93 × 1. 94 1. 58 × 1. 58 1. 73 × 1. 73 1. 82 × 1. 83 1. 66 × 1. 67 1. 82 × 1. 83 se ct io n n o. 1 1 1 1 2 2 2 3 3 fig. (1): relationships between materials cost/ unit meter length and dimensions of inverted siphon. fig. (2): typical section for inverted siphon. vc θ main road ∆ hint: length of siphon= l1+l2+l3 0.40 0.50 0.60 0.70 0.80 0.90 1.00 dimension of siphon (m) 25000 50000 75000 100000 125000 150000 175000 200000 225000 250000 275000 300000 325000 350000 c os t ( i.d ) cost of concrete pipes cost of concrete box cost of steel pipes al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 59 fig. (3): relationships between cost and discharge of inverted siphon. 4 6 8 10 12 14 16 18 20 22 24 26 28 30 discharge (m3/s) 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 c os t * 1 0^ 7 (i. d ) with variable velocity and constant elevation with constant velocity and variable elevation 14-2-2011.pdf 156 the primary objective is to determine whether the structural efficiency of plates can be improved with variable thickness. the large displacement analysis of steel plate with variable thickness at direction is obtained numerically, using finite differences. the effects of boundary condition, tapering ratio, type of tapering equation and plate aspect ratio on large deflection behavior of rectangular plates are investigated. numerical results for rectangular steel plate are presented for the different effects. this study showed that the large deflection behavior is very sensitive for thickness variation (tapering ratio) where the maximum deflection will increase about 5% for slenderness ratio ( / =100) and tapering ratio (1-2) of simply supported plate. : ـل .فعالیة لتحلی . ل . ، نسبة، . ) ()5% ()( / =100 )٢-١ ( . 157 plate dimension in and directions respectively. = clamped edge. =slope coefficient of the tapered plate. 23 112 modulus of rigidity. modulus of elasticity. , , in-plane forces (per unit width). transverse load (per unit area). = simple supported edge. plate thickness. thickness at the side = . = average thickness (( + )/2). thickness at the side =0. poisson’s ratio. out-of-plane displacement (or deflection). with the increasing use of rolled, machined, or them-milled skins in aircraft and missile designs, analyses of plates tapered in thickness are becoming the rule rather than the exception. design data for the large displacement of such plates are limited(2). nonlinear structural problems usually fall into one of the following main categories: (a) large deflections; (b) finite strains; (c) nonlinear material properties; (d) deformation-dependent interactions between structural parts; (e) combination of nonlinear material behavior with one of the other categories. the problem of geometrical nonlinearity is of considerable practical interest for aerospace engineers and naval architects. in civil engineering, hanging roofs, suspension bridges, etc. constitute the most important class of structures which display pronounced geometrical nonlinearities(2). the function of a thin plate element is generally to withstand a distributed lateral pressure, or to act with the adjoining structure in sustaining in-plane forces, or both. although the equations of the large deflection behavior of plates were first derived by von karman, it is only through recent advances in the development of numerical methods that the general problem of plates has been treated satisfactorily. the early investigators used infinite double fourier series (levy[12]) and finite differences (basu and chapman[3]). they studied the large deflection behavior of thin plate under uniformly distributed loading. aalami and chapman[1] used the finite difference method to obtain solutions for a number of isolated plates under uniformly distributed loading and with simple boundary conditions. ueda, et al.[4] studied the large deflection behavior of a rectangular plate by an efficient semi-analytic method. an incremental form of the governing differential equations of plates and stiffened plates with initial deflection had been derived. for each load increment, these equations were solved by galerkin method with special consideration of simple supported boundaries. recently, jayachandran, et al.[5] derived incremental matrices for thin initially imperfect plates with a small out-of-flatness by using minimum potential energy principles. explicit coefficients of the displacement gradient tensor had been evaluated. these matrices were used in combination with any thin plate element. the formulations were incorporated in software plot-cold. the basic concepts of three methods (or steps) for the solution of the large deflection behavior of plates together with a description of the boundary conditions of the cases examined are summarized in the following. 158 starting from the equilibrium of compatibility of a thin plate element and expressing the strains and curvatures as functions of the stress resultants, the following equations are presented(2): the stress-strain relationships become as follows: where ; in which ; and denote the thickness at the sides 0 and , denote to type of equation. after derivation of strains and substitute the derivations into equation (1) and express it as a stress function resultant where the compatibility equation becomes: . (3) by similar algebraic steps it is possible to write the equilibrium equation in terms of and φ, thus: . (4) where )( )( (5) 159 and the variable is airy’s stress function and is defined such that: ;; (6) all the other quantities related to the bending and membrane actions of the plate can be expressed in terms of two variables ( ) and ( )(2). the boundary conditions considered for = , , as shown in figure (1), are as follows: 1-boundary on rigid supports (7) 2for rotationally free cases (on edge parallel to -axis) (8) for rotationally fixed cases(on edge parallel to -axis) (9) for membrane action cases of fully free is considered. 3-for fully free condition of zero membrane direct stress (on edge parallel to -axis) (10) zero membrane shear stress (on edges parallel to or -axis) (11) equations (10) and (11) refer to the boundary condition of an isolated free plate(2). for solution, the plate is subdivided into a graded mesh. the grading is chosen to be fine under distributed loading and for the fixed boundary conditions for increased accuracy. equations (3) and (4), together with the boundary conditions are expressed at the nodes in terms of central finite difference expressions, as shown in figure(2). the resulting equations may then be arranged into the following coupled matrix form: (12) (13) in which [ ] = a square matrix with constant coefficients depending on ; [ ] = a square matrix depending on ; [ ] = a square matrix for bending effect obtained from the left hand side of equation (13); [ ( )] = a square matrix depending on ; { } and { } = column matrices of the unknown variables and , respectively; { } = the applied transverse loading. for numerical evaluation, it is convenient to rewrite equation (10) as follows: 1 (14) 160 now for any specified conditions, equations (12) and (13) can be solved for and using an iterative procedure. there are various schemes used for the solution of the present type of coupled equations. in the present study, the successive iteration procedure is considered. the solution to be obtained for a given applied loading { } is achieved by assigning a value to (which may be assumed equal to zero for first loading, and equal to the previous values for subsequent loading). thus equation (12) can be solved for { }, from which [ ] is evaluated, and subsequently used in equation (13) to get new values of . the procedure is repeated until a desired degree of accuracy is reached. there are certain refinements in the iteration, which are employed to ensure a rapid convergence. a computer program was written by amash [2] and developed to take the out of plane loading and multi equations of variable thickness. the program is written in fortran 90 language. all the solutions presented were obtained with a specified degree of accuracy ( ) of 0.1% in the iterative procedure. in most cases the plate was divided into 16 divisions in any direction. this was considered adequate for obtaining deflections which are accurate enough for practical purposes. ideally it would be desirable to compare the theoretical predictions of the program with the results of carefully controlled experiments and other theoretical results. the accuracy of the results of the present study in the analysis of real panels is compared with the theoretical results obtained by levy (11) [1942] on simply supported panels. the numerical analysis of levy based on the infinite double fourier series for the non-linear analysis of general steel-plate. in the present study, this plate is analyzed based on the prescribed procedure and it is divided into (16 16) divisions. figure (3) shows a comparison between the theoretical results of levy’s study and the present study for the out-of-plane displacements. the curves shown relate the applied load ( 44 ) on the vertical side to the non-dimensional maximum deflection ( ) on the horizontal side. a similar format is adopted for all other figures. it is clear from this figure that good agreement between the results by the present method and the experimental results and the theoretical results is obtained for a simply supported thin plate. figure (4) presents the load-deflection curve of a square simply supported plate under transverse uniform load. the effect of a variation in thickness is considered. the values of tapering ratio are taken to be ( / =1.0, 1.5, and 2.0). so, the modulus of elasticity for all plate in this study was taken equal to 200 gpa. this figure shows that the effect of tapering ratio on large deflection behavior is considerable when the applied load is increasing. the increase in the effect of tapering ratio will be more appearing when the effect of membrane action becomes more appearing. figure (5) presents the load-deflection curve of a square thin plate with all edges clamped. this figure shows a comparison between the constant thickness and the variable thickness in perfect plate. the effect of variation in thickness is very clear on large deflection behavior of thin plates. this effect is appearing in the beginning of loading of plate by transverse uniform load. the effect 161 of material nonlinearity is neglected in the present study. these results are compared for a plate with constant thickness (ordinary plate) and with average thickness which is equivalent thickness of ordinary plate. figure (6) presents the load deflection curve of a square plate with two edges simply supported and other edges clamped and under transverse uniform load. this figure shows the effect of boundary condition and tapering ratio on the large deflection behavior of a square plate under uniform lateral load. figures (7) and (8) presents the load-deflection curve of a rectangular simply supported thin plate under uniform lateral load with aspect ratios ( / =2.0 and 0.5), respectively. these figures show the effect of tapering ratio on the large deflection behavior of a rectangular thin plate with increasing and decreasing in the length in -direction (parallel to the variation in thickness). from figures (7) and (8), the following is noticed: 1the values of the deflection of the thin plate with aspect ratio ( / =2.0) and under uniform load are less than the values of the deflection of the thin plate with aspect ratio ( / =0.5). this difference is due to the effect of tapering ratio on the plate where the deflection becomes larger for the plate with aspect ratio ( / =0.5). 2the effect of tapering ratio on large deflection behavior of a thin plate with aspect ratio ( / =0.5) is more than the effect of tapering ratio on large deflection behavior of a thin plate with aspect ratio ( / =2.0). figures (9) presents the load-deflection curve of a rectangular simply supported thin plate under uniform lateral load with aspect ratios ( / =1.0), slenderness ratio ( / =100), tapering ratio ( / =1.5) and varying values of tapering equation ( from 1-4). this figure shows the effect of tapering equation on the large displacement behavior of a rectangular thin plate. from this figure, can be noticed that the effect of tapering decrease with increasing the order of tapering equation. a simplified computational procedure is used to study the large deflection analysis of a rectangular thin tapered plate under lateral uniform load. approximate values can be obtained with a good accuracy when compared with other works. the effects of boundary condition, tapering ratio and plate aspect ratio on the large deflection behavior of rectangular thin tapered plates are studied and presented in graphs. the tapering ratios are taken to be ( / =1.0,1.5,2.0). it is shown that the large deflection behavior is dependent on the tapering ratio. so the effect of order of tapering ratio shows that the deflection of steel plate increases with increase the order of tapering ratio. the effect of tapering ratio is dependent on plate aspect ratio. in the present study, the material nonlinearity, initial imperfection, free and rotationally boundary condition are not considered. aalami,b., and chapman, j.c., “large deflection behavior of orthotropic plates under transverse and in-plane loads”, proc. ice, london, england, vol.42, mar., 1969, pp.347-382. amash,h.k., “post-buckling and post-yielding analysis of imperfect thin plate by finite difference method.” m.sc. thesis, university of babylon, february 2003. 162 basu, a.c., and chapman j.c., “large deflection behavior of transversely loaded rectangular orthotropic plates”, proc. ice, london, england, vol.35, sept., 1966,pp.79-110. bjelajac, n., “evaluation of post-buckling equilibrium branches for perfect and imperfect plates by finite difference method”, numerical methods in continuum mechanics, liptovskk َy jaَn, slovac republic, 2000, pp.1-18. chajes, a., “principles of structural stability theory”, prenticehall, inc., englewood cliffs, new jersey, 1974. chia, c.y., “nonlinear analysis of plates”, mcgrawhill international book company, 1980. coan, j.m., “large deflection theory for plates with small initial curvature loaded in edge compression”, j. appl. mech., vol.18, june, 1951, pp.143-151. colville, j., becker, e.b., and furlong, r.w., “large deflection analysis of thin plates”, asce, j. struc. div., vol.99, no.st3, mar., 1973, pp.349-364. husain, h.m., al-daami, h., and amash, h.k., “buckling behavior of rectangular plate with variable thickness.” engineering & technology (baghdad) vol.21, no.10, 2002, pp.736-745. klein, b. "shear buckling of simply supported rectangular plates tapered in thickness", j.f.i.,june 1957, pp537-541. jayachardalan, s.a., gopalakrishnan, s., and narayana, r., “explicit incremental matrices for the post-buckling analysis of thin plates with small initial curvature”, an international struct. eng. and mech., vol.12, no.30, 2001, pp.283-295. levy, s., “bending of rectangular plates with large deflections” naca report 737, (u.s.a.) 1942. murray, n.w., “introduction to theory of thin walled structures”, oxford univ., press, new york, 1986. rushton, k.r., “large deflection of plates with initial curvature”, int. j. mech. sci., vol.12, 1970, pp.1037-1051. salvadori, m.g., “numerical computation of buckling loads by finite differences”, asce, trans., dec., 1949, pp.590-636. saxena, h.c., “the calculus of finite differences”, s. chand & company, ltd, 1980. szilard, r., “theory and analysis of plates: classical and numerical methods”, prenticehall, inc., englewood cliffs, new york, 1974. 163 timoshenko, s.p., and woinowshy, s., “theory of plates and shells”, 2nd ed, mcgraw-hill book co., inc., new york, 1959. timoshenko, s.p., and gere, j.m., “theory of elastic stability”, 2nd ed, mc graw-hill book co., inc., new york, 1961. ueda, y., rashed, s.m.h., and paik, j.k., “an incremental galerkin method for plates and stiffened plates”, comp. & struct., vol.27, no.1, 1987, pp.147-156. ugral, a.c., “stresses in plates and shells”, mcgraw-hill, inc, 1981. wang, p.c., “numerical matrix method in structural mechanics”, john wiley & sons, inc., new york, london, sydney, 1966. williams, d.g., and aalami, b., “thin plate design for in-plane loading”, halsted press, a division of john wiley & son, inc., new york, 1979. 4 2423 23 22 222 42 234 )(2 42 234 )(2 44 2423 23 4 plate equation in finite difference molecule form(2) 164 load-deflection curve of a square simply supported thin plate under transverse uniform load s s s s central deflection of simply supported square plate versus uniform lateral load 165 load-deflection curve of a square thin plate with all edges clamped and under transverse uniform load load-deflection curve of a square thin plate with two edges simply supported and other edges clamped under transverse uniform load 166 load-deflection curve of a rectangular simply supported plate with aspect ratio ( / =2.0) and under transverse uniform load load-deflection curve of a rectangular simply supported plate with aspect ratio ( / =0.5) and under transverse uniform load 167 load-deflection curve of a rectangular simply supported plate and under transverse uniform load with different values of order tapering equation <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 36 evaluation of groundwater quality in selected areas of najaf governorate for different purposes dr. saleh issa khassaf, prof. in civil eng. dept., basra university email: salehissakh@gmail.com fatima mohsen kizar, lect. in civil eng. dept., kufa university e-mail: fatimahm.alhasnawi@uokufa.edu.iq eng. firas fadhil hassan, manager of najaf environment directorate email: firass_esa@yahoo.com received on 30 august 2016 accepted on 07 december 2016 abstract this study is concerned with assessing suitability of groundwater in selected areas of najaf governorate, iraq, for multiple uses ( human drinking , animal drinking , industrial , agricultural and irrigation). water samples were taken from 29 wells over eleven months (january december 2014); these samples were chemically and microbiologically analyzed using eleven parameters: electrical conductivity ( ec ), total dissolved solid ( tds ), ph values, calcium (ca +2 ), magnesium ( mg +2 ), sodium (na + ), chloride ( cl ), sulphate ( so4 -2 ), nitrate (no3 ), total hardness ( t.h ) and total coliform bacteria ( t.c ). sodium adsorption ratio ( sar) was also calculated to be compared with standards. it is found that the groundwater of the study area is not suitable for human drinking and industrial purpose (except groundwater of one well which was suitable for chemical industry and refinery ) because of high concentration of chemical variables, but it was suitable for animal consumption and irrigation vegetables which resist moderate and high concentrations of ec in water, a salinity problem was expected based on todd and american salts laboratory classifications, there were no harmful effects from sodium indicators on plants, most of water samples were within the classes poor and very poor for irrigation use according to richard classification, and chloride toxicity problem was expected because 69 % of groundwater samples can cause severe problems. key words: evaluation, groundwater , wells, najaf, irrigation. تقییم صالحیة المیاه الجوفیة في مناطق مختارة من محافظة النجف لألغراض المختلفة عیسى خصاف جامعة البصرة / كلیة الھندسةأ.د.صالح م. فاطمة محسن كزار جامعة الكوفة / كلیة الھندسة مدیر دائرة البیئة في النجف /المھندس فراس فاضل حسن المستخلص : العراق لالستخدامات المتعددة ( الش@رب /في مناطق مختارة من محافظة النجف تھتم ھذه الدراسة بتقییم صالحیة المیاه الجوفیة ) بئ@را خ@الل اح@د عش@ر ش@ھرا ( ك@انون ٢٩اخ@ذت عین@ات المی@اه م@ن ( .الزراعی@ة وال@ري ) ,الص@ناعیة ,شرب الحیوانات ,البشري االمالح الذائب@ة ,عشر مؤشرا : الموصلیة الكھربائیة تم تحلیل ھذه العینات كیمیائیا وبایولوجیا ألحد ,م ) ٢٠١٤كانون االول -الثاني ت@م .بكتریا القولون الكلیة ,العسرة الكلیة ,النترات ,الكبریتات ,الكلوراید ,الصودیوم ,المغنسیوم ,الكالسیوم ,الرقم الھیدروجیني ,الكلیة جوفی@ة غی@ر مناس@بة للش@رب البش@ري والغ@رض بین@ت الدراس@ة ان المی@اه ال .حساب نسبة امتزاز الصودیوم لمقارنتھا م@ع المواص@فات الص@@ناعي ( ماع@@دا المی@@اه الجوفی@@ة لبئ@@ر واح@@د كان@@ت مناس@@بة للص@@ناعات الكیمیائی@@ة والمص@@افي) بس@@بب التركی@@ز الع@@الي للمتغی@@رات .الم@@اء لكنھ@@ا كان@@ت ص@@الحة لالس@@تھالك الحی@@واني وري الخض@@روات الت@@ي تق@@اوم تراكی@@ز عالی@@ة ومعتدل@@ة م@@ن الملوح@@ة ف@@ي ,الكیمیائی@@ة ومختبر الملوحة االمریكي توجد مشكلة الملوحة ولكن ال توجد تأثیرات ضارة من مؤشرات الص@ودیوم toodاعتمادا على تطبیقي al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 37 مش@كلة richard . الس@تعمال ال@ري طبق@ا لتص@نیف very poorو poorمعظم عین@ات المی@اه كان@ت ض@من الص@نف .على النباتات .) من عینات المیاه الجوفیة كانت تسبب المشكلة ٦٩ %سمیة الكلورید كانت موجودة الن( nomenclature ca +2 calcium ion cl chloride ion ec electrical conductivity mg +2 magnesium ion na + sodium ion no3 nitrate ph hydrogen ion concentration ppm part per million sar sodium adsorption ratio so4 -2 sulphate t.c total coliform bacteria tds total dissolved solids t.h total hardness µmohs /cm micro mohs per centimeter introduction of all natural resources, water is necessary and precious as life began with water, and life is nurtured by water. there are organisms, such as anaerobes, which can stay alive without oxygen, but no organism can stay alive without water. water is a essential material for life. the total water existing for drinking is 0.3% from the total water found on the surface of the earth. rivers, streams, lakes and reservoirs have long been significant sources of drinking water. in the past, these sources were often heavily polluted by sewage discharge and, unfortunately, were also significant in the transmission of communicable diseases such as typhoid and cholera ( alobaidi, 2009). surface waters are facing an rising trouble through the disposal of pollutants due to the rapid growth of industrial and municipal actions because of the population expansion as well as the increase in land drainage due to agricultural activities. thus, there has been an increasing concern about groundwater quality all over the world. groundwater is usually understood to mean water occupying all the voids inside a geologic layer. this saturated zone is to be distinguished from an unsaturated, or aeration, zone where voids are filled with water and air. water contained in saturated zones is significant for engineering work, geologic researches, and water supply developments. unsaturated zones are commonly found above saturated zones and extend up to the earth surface, because water here includes soil moisture inside the root zone; it is a main concern of agriculture, botany, and soil science. no rigid demarcation of waters between the two zones is possible, for they possess an interdependent edge, and water can move from zone to zone in either way ( tood, 2005). there are two sources of groundwater: rain that penetrates the soil through pores and cracks in rock formations and finally up to the surface of groundwater. the second source is the water of rivers and lakes which is carried out through the soil to surface of groundwater. groundwater is considered the second main source of water all over the world and it hits the surface of the earth through the eyes and springs or drilling wells; the right benefits of this water are drinking, agricultural, livestock production and industrial uses where surface water is scarce or does not exit. groundwater represents one of the most important sources of water in rural areas. in many areas , it constitutes the largest storage of suitable drinking water and the only source of water for local, irrigation and industrial purposes. generally, groundwater is preferred to surface water because it is al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 38 less susceptible to contamination and it is slightly below the surface of the ground; in addition to that it is of constant temperature and available in many areas even those that are exposed to severe drought for many years. in najaf _ iraq, shatt alkufa ( kufa river ) is the major supply of water needed for drinking, irrigation, industry and other applications. this river shows decreasing quantity and quality of water because of the rapid growth of industrial, agricultural and municipal activities. groundwater is another important source of water in this governorate especially for irrigation. in the last few years, farmers started to dig wells in many area to use them for agriculture; many vegetables are now produced in considerable amount by using groundwater. the main objective of this study is to evaluate the quality of groundwater in selected areas of najaf governorate by identifying the chemical and microbiological properties and then assess the suitability of this water for various purposes. study area najaf is situated in the south of iraq ( the mideuphrates region ). it is situated between ( 42 o 50 / 45 o 44 / ) longitude and ( 29 o 50 / 32 o 21 / ) latitude ( almthafer, 2011) . in this study four areas were selected from najaf to evaluate their groundwater: najaf city, najaf – karbala road, najaf sea and kufa city, each of which contains a number of studied wells, see fig (1). najaf city is the center of najaf ( largest urban center ). it is surrounded by a group of urban centers: al-haidariya city to the north, kufa city to the east, almanathira city to the southeast and it is honorable on low of najaf sea which is one of the more geomorphological phenomenas in the study area; where a length of ( 40 km ) and width ( 19 km ) while an area ( 366 km 2 ) and away ( 5 km ) from najaf city( aljanabi, 2012). najaf – karbala road is the road which links najaf with karbala. ground elevations in the area rise about (55m) above sea level and the city area covers (183km 2 ) within the basic scheme for the year 2012 to 2035 ( altaghlubi, 2013). the soil of the study area is silty sand on the whole and with high porosity and permeability, which help the groundwater movement to different trends depending on the topography of the land ( al-murshidy, 1998). the climate study is important in studies related to shallow groundwater. the different climate elements play an important role in increasing rainfall and humidity that affect the water content of the soil ( aladili, 1998). the study area has a dry continental climate characterized by a cold winter with little rain and a long hot dry summer with a significant difference in temperature between day and night, table (1) shows the monthly rates of climate elements for the period (1980 – 2014). it was found that the study areas , climate is continental ( desert dry climate ); this type of climate contributes to increasing concentration of salts in water. selected wells and evaluation the purpose of the experimental work in this study is to make an evaluation of groundwater of twenty nine selected wells. these wells and their locations and depths are shown in table (2). the laboratory testing of the chemical and microbiological evaluation was done in najaf environmental directorate / environmental analysis department. the methods of testing the parameters are illustrated in table (3). results and discussion the chemical analysis for the chemical analysis, samples were taken from twenty nine selected well over the period jan. 2014 to dec 2014; locations of selected wells are marked as shown in fig (1). these samples were chemically analyzed for different elements. these elements are ( ec, tds, ph, ca +2 , mg +2 , al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 39 na + , cl , so4 -2 , no3 and th ). sodium adsorption ratio ( sar ) was also calculated to be compared with its standard limitation. the results of chemical analysis of groundwater of the selected wells and values of calculated (sar) are shown in table (4). each analyzed chemical element was also plotted in figs ( 2 11). the microbiological analysis samples were also microbiologically analyzed for total coliform bacteria. table (5) showed results of these analysis of groundwater of selected wells. results were also plotted in fig (12). suitability of groundwater for different uses chemical, physical, and biological properties are determined qualities of water and its uses for different purposes such as human use, irrigation, and industry … etc. a chemical quality of water is as important as the availability of water itself, because the water can be suitable for a specific use and unsuitable for another. suitability of groundwater for human drinking standard specifications of the iraqi specification (iqs – 2001) and world health organization (who ) were adopted in evaluation the suitability of groundwater in the study area for human drinking. these specifications depend on the concentrations of major positive and negative ions, as well as values of tds, th and ph. specifications refer to the existence limit to concentration of each ion and the increase about this standard limit means that water contaminated with this ion. the comparison between values of the chemical analysis of groundwater in the study area given in table (4) with the corresponding values shown in table (6) shows that the groundwater was unsuitable for human drinking, because the concentrations of all ions as well as the concentrations of tds and th exceeded the permissible limits in the standard specifications. as known, water which contains tds greater than ( 1000 ppm ) will be unpalatable for drinking. for the total coliform bacteria of groundwater table (7) sets water quality criteria for microbiological indicators for british columbia, which are bacteria representing the danger of illness from pathogenic bacteria. the comparison between values in the study area given in table (5) with the values shown in table (7) shows that some of groundwater of wells were needed disinfection only, other were needed partial and complete treatment when were used for drinking. suitability of groundwater for industrial purposes the quality of water available for industrial purposes should take a broad range because each industry has a private specification. some industries do not require critical limits but using any type of provided water; for example, the industry of raw materials concentration while other industries like pharmaceutical industry and paper with high quality industry are required water quality equals to distilled water in purity because water quality affects the quality and safety of product. some industries such as the operation of modern steam boilers with high pressure are needed water purity outweigh the commercial distilled water ( mania, 2003). the values of groundwater were also compared to the proposed limits in table (8) . the result was that groundwater was not suitable for all industries (except groundwater of w23 was suitable for chemical industry and refinery) because high concentrations of hardness, calcium, magnesium, chloride and sulfates. kufa cement factory is existed in the study area and near the well (w23). the comparison between results of chemical analysis of groundwater of (w23) with the limits shown in table ( 8) shows that the groundwater of the well is suitable to use in cement industry because the low concentrations of positive and negative ions, total hardness and total dissolved solid. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 40 suitability of groundwater for animal drinking most animals can drink poor quality water which human cannot drink. proposal specification of altoviski table (9) for animal consumption were compared with the data given in table (4) to assess the suitability of groundwater for livestock and poultry drinking. the result of comparison was that the groundwater of the study area was fit for animal consumption because the concentrations of positive and negative ions, total hardness and total dissolved solid were within the permitted limits. suitability of groundwater for agricultural purposes plants are different in resisting salinity of irrigation water. table (10) shows the satisfactory limits of salinity in irrigation water for various crops based on ec standards which were classified by tood classification. the data given in table (4) were compared with limits of salinity shown in table (10). the result of comparison was that: ( 1 ) water from w21 and w23 only was suitable to agriculture all crops because their salinity was low. ( 2 ) water from w17 suitable to agriculture all crops except fruit resisting low concentrations of ec in water. ( 3 ) water from all wells except ( w14 ,w15 and w20 ) was suitable to agriculture cucumber, feas, onion, carrot, potato, lettuce, cauliflower, tomato , sunflower, flax, corn, rice, wheat, spinach, kale, beet, cotton, sugar beet and barley because these crops are tolerated moderate and high salinity of groundwater. ( 4 ) water from ( w14 ,w15 and w20) was suitable to agriculture cotton, sugar beet, barley because of high salinity. suitability of groundwater for irrigation purposes the selected criteria to evaluate the quality of irrigation water should show its ability to cause adverse changes in soil properties or detrimental effect on the crop, animal, or human who consumes this crop. three characteristics are usually used to assess irrigation water: salinity, sodicity and toxicity. salinity problem salinity represents the potential danger of damage to plant. the electrical conductivity ( ec ) is usually used to express the contain of salinity. there are two kinds of salt troubles: one related to the total salinity and another related to sodium. these two troubles may be affect on soils. table (11) shows tood categorization of irrigation water according to (ec) values. according to tood classification, the test results showed that the ec values fall within the water class of unsuitable except values of ( w21 and w23 ) fall within doubtful and permissible classes respectively. tds values were categorized into four – classes based on american salts laboratory as illustrated in table (12). based on the classification of ( tds ) values which stated by the american salts laboratory, the test results showed that the groundwater of the study area is outside the limitation of the classification except ( w23 ) fall within c3 and (w4 , w5, w7 ,w9, w13, w17 and w21) fall within c4. sodium problem sodium adsorption ratio ( sar ) is recommended by the salinity laboratory of the u.s. department of agriculture because of its straight relation to the adsorption by soil. it is defined by the following equation: )/ 2 na ca mg sar + = ( 1) where the unit epm (milli equivalent per liter) is used to express the concentration of the elements. ( tood, 2005). the effect on soil permeability and water infiltration is the major trouble with high sodium concentration. sodium also may be toxic to sensitive crops because it contributes directly to the al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 41 total salinity of the water. the sodium causes dispersion of soil particles because it replaces calcium and magnesium adsorbed on clay minerals. the breakdown of soil aggregates results from this dispersion and causes a cementation of the soil under drying conditions as well as preventing infiltration of rain water. the groundwater of the study area is classified according richard classification with respect to the values of ( sar and ec ) in water as shown in tables (13 and 14). also fig (13) shows a diagram for the classification of irrigation water. the test results showed that the sar values in irrigation water varied from ( 0.305 17.18 ). based on the classification of ( richard , 1954 ) for ( sar ) values, there was no harmful effects of sodium on plants because all the values of sar ( except value of w7 ) were less than ten. table (14) and fig (13) showed that most of the water samples were within the classes ( poor and very poor ) which index ( c4s1, c4s2 and c4c4 ) for agriculture use except ( w23 ) was within the class ( appropriate ) which index ( c3s1). toxicity problem chloride ( cl ) is found in most normal waters. it is harmful to some plants in high amounts. all common chlorides are soluble and contribute to the total salt content ( salinity ) of soil. in evaluation of irrigation waters the chloride content should be calculated, if( tds ) is greater than ( 1000 ppm ), chloride should be below ( 300 ppm ) to avoid harm to citrus ( boman, 2002 ). chlorine does not adversely affect on soil properties; so, soil quality is neglected in classification of the quality of irrigation water for concentration of chlorine ( asmaeel, 1988). chloride is necessary to plants in very low concentrations, it can cause toxicity to sensitive crops at high amounts ( mass, 1990). table (15) shows chloride classification of irrigation water. the chloride test results showed that all groundwater samples were above ( 141 mg / l ) except water from (w23 ) it was within ( 70 – 140). so, sensitive plants show injury from this water, (28% ) of groundwater samples were within (141350 ) so moderately tolerant plants show injury and ( 69 % ) of samples were above ( 350 mg / l ) so can cause severe problems. coliform bacteria awareness is growing that fresh or minimally processed fruit and vegetables can be sources of illness – causing bacteria, viruses, protozoa, and helminthes. fruit and vegetables can become polluted with food borne pathogens when poor – quality water is used for irrigation. the risk of disease transmission from pathogenic. the level of pollution; the persistence of pathogens in water, in soil, and on crops; and the route of exposure influence on microorganisms present in irrigation water . bacteria and protozoa tend to show the poorest survival outside a human host, whereas viruses and helminthes can remain infective for months to years ( albahrani, 2012). table (16) sets water quality criteria for microbiological indicators for british columbia, which are bacteria representing the danger of illness from pathogenic bacteria. the comparison between values of the total coliform bacteria of groundwater in the study area given in table (5) with the values shown in table (16) shows that all groundwater samples except groundwater of (w29) were used in general irrigation. conclusions 1. groundwater of the study area was unsuitable for human drinking because the concentrations of all ions as well as concentrations of tds and t.h exceeded the permissible limits in the standard specifications. the values of tds were ranged between ( 937 – 8676 ) ppm, while t.h values were between ( 590 – 3700 ) ppm. 2. for drinking total coliform bacteria results showed that some of groundwater wells were needed disinfection only, other were needed partial and complete treatment. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 42 3. groundwater was unfit for all industries (except groundwater of w23 was suitable for chemical industry and refinery ) because of very high concentrations of hardness, calcium, magnesium, chloride and sulfates. the concentrations of ca +2 and mg +2 were between ( 162.4 – 1080 ) ppm and ( 27.5 – 412.4 ) ppm, respectively. the sulfate concentrations were ranged between (256.9 – 2666.3 ) ppm were as the chloride concentrations were between ( 135 – 2150 ) ppm. 4. groundwater was fit for animal consumption because the concentrations of positive and negative ions, total hardness and total dissolved solid were within the permitted limits for animal drinking. 5. water form w21 and w23 only was suitable to agriculture all crops because of its low salinity. 6. most of groundwater of the study area was suitable to agriculture vegetable crops and field crops which resist moderate and high concentrations of ec in water. 7. according to todd classification of irrigation water based on salinity ( ec ), the test results showed that the ec values fall within the water class unsuitable because of all the values were greater than ( 3000 µs /cm ) except values of ( w21 and w23 ) fall within doubtful and permissible classes respectively. 8. based on the classification of ( tds ) values which stated by the american salts laboratory, the test results showed that the groundwater of the study area is outside the limitation of the classification except ( w23 ) fall within c3 and (w4 , w5, w7 ,w9, w13, w17 and w21) fall within c4. 9. based on the richard classification for (sar) values, there was no harmful effects from sodium on plants because all the values of (sar ) ( except value of w7 ) were less than ten. sar values varied from ( 0.305 – 17.18 ) in groundwater. 10. most of the water samples were within the classes (poor and very poor) which index (c4s1, c4s2 and c4c4) for agriculture use. 11. according to chloride mass classification (28%) of samples show injury to moderately tolerant plant and ( 69 % ) of samples can cause severe problems. 12. for irrigation total coliform bacteria results showed that all groundwater samples (except w29 ) were used in general irrigation. references 1. abdulrazzaq, k. a. and kamil, w. s. 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(in arabic ) 16. mania, j. k. " hydrochemical of groundwater and metal of sediment for open water reservoir in selected areas of babylon". m.sc thesis, faculty of science, university of baghdad, 2003. 17. mass "crop salts tolerance". agricultural salinity assessment and management manual. k.k. tanji (ed.). asce, new york, 262 – 304, 1990. 18. todd d. k. and mays l. w. " ground water hydrology". 3 rd edition, john wiley and sons, university of california , isbn : 0 – 471 – 05937 – 4 , 636 pages, 2005. 19. warrnigton, p. d. "water quality criteria for microbiological indicators". overview report, environmental protection division, ministry of water, land and air protection, government of british colombia, second edition, 2001. table (1) average monthly temperature, relative humidity % , rainfall and evaporations values in najaf for the period ( 1980 _ 2014 ) ( alkelabbee, 2016) months j. f. m. a. m. j. j. a. s. o. n d. temperature ( c 0 ) 10.8 13.4 17.9 23.9 29.9 33.7 35.7 35.4 32 26.4 18.2 12.65 relative humidity % 70 60.3 51.4 43.7 33.4 27.8 27 29 33.2 43.3 29.2 70.1 rainfall ( mm ) 20.7 15.1 13.5 10.2 4.1 0 0 0 0 4.2 14.8 17.5 evaporation (mm ) 72.7 122.9 201.3 285.7 409 531.4 579.5 538.3 403.1 268.2 144.1 87.6 table( 2) wells locations and depths well symbol location wells depths (m ) well symbol location wells depths ( m ) w1 najaf city 30 w16 kufa _ w2 najaf city 50 w17 najaf sea 90 w3 najaf city 50 w18 najaf sea 45 w4 najaf city 50 w19 najaf sea 15 w5 najaf city 20 w20 kufa 30 w6 najaf city 160 w21 kufa 30 w7 najaf city 10 w22 kufa 25 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 44 table( 3) methods of testing the concentration of the ions in groundwater parameter method of testing unit ec ecmeter µmohs/cm tds method of drying (or weight method ) ppm ph ph meter ca , mg and th titration with the na2 – edta ppm na flamephotometer ppm cl titration with the agno3 ppm so4 burning ppm no3 spectrophotometer ppm table( 4) results of chemical analysis of groundwater of selected wells ele. well no. ec (µmohs/ cm) tds (ppm) ph ca +2 (ppm) mg +2 (ppm) na + (ppm) cl (ppm) so4 -2 (ppm) no3 (ppm) th (ppm) sar w1 5547 3327 6.7 600 73.2 453.5 450 1430.4 61.7 1800 4.641 w2 5397 3588 7.0 624 131.7 262 590 1876 62.28 2100 2.481 w3 5531 3597 6.9 640 117.12 228 660 1047.4 58.38 2080 2.169 w4 4160 2716 7.5 550 101 298.5 658 2261.5 56.7 1790 3.063 w5 4574 2973 7.3 656 56.12 118 310 1333.1 21.7 1870 1.185 w6 7236 4342 7.3 376 197.6 406 143 685 5.49 1750 4.204 w7 4282 2782 6.3 504 124.4 1666.4 350 1100 3.27 1770 17.18 w8 5168 3362 5.1 595 149 209.1 600 1202 63.6 2020 1.98 w9 4400 2860 5.2 520 130 282 300 904 44.7 1833 2.857 w10 5064 3290 8.5 585 146 216.5 348 1118.6 3.8 2060 2.069 w11 7443 4837 6.5 800 170.8 850.5 1350 1192.5 17.09 2700 7.101 w12 7400 4820 6.9 872 185.4 860 1685 1547.5 18 2940 6.881 w13 4021 2813 6.6 520 122 142 226 1728.4 8.3 1800 1.452 w14 11900 7140 7.4 780 195.2 584.5 1616 2380.5 77.9 2750 4.834 w8 najaf city 10 w23 kufa 20 w9 najaf city 25 w24 kufa 35 w10 najaf city 12 w25 kufa _ w11 najaf – karbala road 35 w26 kufa _ w12 najaf – karbala road 35 w27 kufa 30 w13 najaf – karbala road 10 w28 kufa 20 w14 najaf city 48 w29 kufa 25 w15 najaf city 50 _ _ _ al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 45 w15 14460 8676 7.5 740 156.16 762.5 405.6 2380 92.9 2490 6.629 w16 7666 5568 7.0 544 412.4 858 2116 2300 80 3050 6.724 w17 3595 2340 6.4 388.8 150 250 644 1000 3.23 1572 2.73 w18 7065 4593 7.1 416 222 347 1150 1352 7.13 1950 3.403 w19 7489 4867 6.8 448 212.2 362 1000 1409.2 73.2 1990 3.516 w20 11170 5650 7.5 1040 268.4 90 2150 2004 27.2 3700 0.642 w21 2529 1646 7.8 240 53.4 20.14 280 642.5 23.2 820 0.305 w22 9111 5913 7.3 660 27.5 620.2 1400 2666.3 124.7 2200 6.419 w23 1464 937 7.8 162.4 44.8 102.1 135 256.9 5.44 590 1.823 w24 8090 4060 8.1 1080 239.1 1040 223.5 2128.4 3.45 2680 7.437 w25 7970 5455 6.8 560 341.6 994 2058 1500 50 2800 8.133 w26 8150 5583 6.8 800 226.9 1064 1666 1400 60 2930 8.524 w27 5020 3263 7.4 656 209 250 540 1523.6 63.7 2500 2.169 w28 5700 3455 7.0 600 73.2 248 400 1961 58.2 1800 2.538 w29 6713 3963 6.9 624 107.3 254.6 475 2214 10.32 2000 2.471 table( 5) results of microbiological analysis of groundwater of selected wells well no. w1 w2 w3 w4 w5 w6 w7 w8 w9 w10 w11 w12 w13 w14 w15 t.c /100ml _ 8 4.6 23 240 _ 0 46 70 23 _ 0 8 _ _ well no. w16 w17 w18 w19 w20 w21 w22 w23 w24 w25 w26 w27 w28 w29 t.c /100ml _ _ 5.1 23 _ 23 23 7.8 _ _ _ 920 31 1600 table( 6) standard specifications for drinking water ( jaber, 2014) parameter tds ph ca mg na cl so4 no3 th units ppm _ ppm ppm ppm ppm ppm ppm ppm ( iqs ) 1500 6.5-8.5 150 50 200 250 250 _ 500 (who) 1000 6.5-8.5 200 150 200 250 400 _ 500 table( 7) water quality criteria for microbiological indicators ( warrnigton, 2001) water use escherichia enterococci pseudomonas fecal coliforms al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 46 aeruginosa raw drinking water – no treatment 0 / 100 ml 0 / 100 ml 0 / 100 ml 0 / 100 ml raw drinking water – disinfection only less than or equal to 10 / 100 ml 90 th percentile less than or equal to 3 / 100 ml 90 th percentile none applicable less than or equal to 10 / 100 ml 90 th percentile raw drinking water – partial treatment less than or equal to 100 / 100 ml 90 th percentile less than or equal to 25 / 100 ml 90 th percentile none applicable less than or equal to 100 / 100 ml 90 th percentile raw drinking water – complete treatment none applicable none applicable none applicable none applicable table( 8) proposal limits for water using in different industries ( jaber, 2014) table (9) water specification for animal consumption ( altoviski, 1962) element (ppm) v. good water good water acceptable use can be use maximum limit na 800 1500 2000 2500 4000 ca 350 700 800 900 1000 mg 150 350 500 600 700 cl 900 2000 3000 4000 6000 so4 1000 2500 3000 4000 6000 tds 3000 5000 7000 10000 15000 th 1500 3200 4000 4700 54000 table (10) acceptable limits of salinity in irrigation water for various crops based on ec values ( al-maliki, 2013) kinds of crops crops resisting low concentrations of ec in water crops resisting moderate concentrations of ec in water crops resisting high concentrations of ec in water fruit crops < 3000 µs /cm lemon , strawberry , peach , apricot , almond , orange , apple , pear ≥ 3000 < 4000 µs /cm olive , figure , pomegranate ≥ 4000 – 10000 µs /cm date palm vegetable crops 3000< 4000 µs /cm ≥ 4000 < 10000 µs /cm cucumber , feas , onion , ≥10000 –12000 µs /cm spinach , kale , beet industries ph th ( ppm ) ca ++ ( ppm ) mg ++ cl (ppm) so4 = ( ppm ) canning food 6.5 – 8.5 310 120 _ 300 250 chemical industry 6 9 1000 200 _ 500 863 cement 6.5 – 8.5 _ _ _ 250 250 refinery 6 9 900 220 85 1600 570 paper 6 9 475 20 12 199 _ al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 47 green bean , celery , badish carrot , potato , lettuce , cauliflower , tomato field crops 4000 < 6000 µs /cm field bean ≥ 6000 < 10000 µs /cm sun flower , flax , corn , rice , wheat ≥10000 –16000 µs /cm cotton , sugar beet ,barley table (11) limitation of salinity for irrigation water based on ( ec) values ( tood, 2005) water class ec ( µs /cm ) excellent < 250 good ≥ 250 < 750 permissible ≥ 750 < 2000 doubtful ≥ 2000 < 3000 unsuitable > 3000 table( 12) american salts laboratory classification of irrigation water based on (tds) values ( al-saffy, 2010) water kind tds ( ppm ) water suitability c1 – less salt 0 < 160 the water is suitable to most plants and soils with a little possibility of soil saltiness c2 – moderate salt ≥ 160 < 480 the water is suitable to plants that can undergo salts increase where there is moderate draining for the soil . c3 – high salt ≥ 480 < 1440 water is suitable for plants that resist salts , and on well – drained lands. it is essential to have a fine draining structure for the soil. c4 – very high salt ≥ 1440 <3200 the water is suitable to plants that are highly resistance to salts , and on pervasive well – drained soils and deep washing for salts. table (13) richard classification for irrigation use ( abdulrazzaq, 2010) water class sar index ec ( ds / m ) index excellent ≤ 10 s1 0.1 – 0.25 c1 good 10 18 s2 0.25 _ 0.75 c2 fair 18 26 s3 0.75 _ 2.25 c3 poor ≥ 26 s4 ≥ 2.25 c4 table (14) groundwater classification according to richard classification for irrigation use index water class no. of well index no. of well water class c1s1 excellent c3s1 w23 appropriate c1s2 good c3s2 acceptable c1s3 appropriate c3s3 acceptable c1s4 poor c3s4 poor al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 48 c2s1 good c4s1 w5, w9, w13, w17, w21 poor c2s2 good c4s2 w4 poor c2s3 acceptable c4s3 very poor c2s4 poor c4s4 w7 very poor table (15 ) chloride classification of irrigation water ( mass, 1990) chloride (ppm) effect on crops below 70 usually harmless for all plants 70 – 140 sensitive plants show harm 141 – 350 moderately tolerant plants show harm above 350 can cause severe troubles table (16) microbiological indicators criteria ( warrnigton, 2001) water use escherichia enterococci pseudomonas aeruginosa fecal coliforms irrigation – crops eaten raw less than or equal to 77 / 100 ml geometric mean less than or equal to 20 / 100 ml geometric mean none applicable less than or equal to 200 / 100 ml geometric mean irrigation public access livestock access less than or equal to 385 / 100 ml geometric mean less than or equal to 100 / 100 ml geometric mean less than or equal to 10 / 100 ml 75 th percentile none applicable irrigation general irrigation less than or equal to 1000 / 100 ml geometric mean less than or equal to 250 / 100 ml geometric mean none applicable less than or equal to 1000 / 100 ml geometric mean al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 49 figure (1) location of the study area in iraq and sampling locations figure 2: ec values for the studied wells 0 2000 4000 6000 8000 10000 12000 14000 16000 w 1 w 3 w 5 w 7 w 9 w 11 w 13 w 15 w 17 w 19 w 21 w 23 w 25 w 27 w 29 wells e c ( m m o h s / c m ) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 50 figure 3:tds values for the studied wells 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells t d s ( p p m ) figure 4: ph values for the studied wells 0 1 2 3 4 5 6 7 8 9 w 1 w 3 w 5 w 7 w 9 w 11 w 13 w 15 w 17 w 19 w 21 w 23 w 25 w 27 w 29 wells p h v a lu e s figure 5: calcium values for the studied wells 0 200 400 600 800 1000 1200 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells c a ( p p m ) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 51 figure 6: magnesium values for the studied wells 0 50 100 150 200 250 300 350 400 450 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells m g ( p p m ) figure 7: sodium values for the studied wells 0 200 400 600 800 1000 1200 1400 1600 1800 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells n a ( p p m ) figure 8: chloride values for the studied wells 0 500 1000 1500 2000 2500 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells c l ( p p m ) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 52 figure 9: sulphate values for the studied wells 0 500 1000 1500 2000 2500 3000 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells s o 4 ( p p m ) figure 10: nitrate values for the studied wells 0 20 40 60 80 100 120 140 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells n o 3 ( p p m ) figure 11: total hardness values for the studied wells 0 500 1000 1500 2000 2500 3000 3500 4000 w 1 w 2 w 3 w 4 w 5 w 6 w 7 w 8 w 9 w 10 w 11 w 12 w 13 w 14 w 15 w 16 w 17 w 18 w 19 w 20 w 21 w 22 w 23 w 24 w 25 w 26 w 27 w 28 w 29 wells t .h ( p p m ) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 53 figure (13) diagram for the classification of irrigation water ( asmaeel, 1988) figure 12: total coliform bacteria for the studied wells 0 200 400 600 800 1000 1200 1400 1600 1800 w 1 w 3 w 5 w 7 w 9 w 11 w 13 w 15 w 17 w 19 w 21 w 23 w 25 w 27 w 29 wells t .c / 1 0 0 m l 2-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 analytical formulation to predict time to failure of the stress corrosion cracking sattar j. hashim mechanical engineering dep., engineering college, university of basrah e-mail address: sattarhas@gmail.com , sattarhas@yahoo.com astract: this work presents an analytical model to predict the time to failure of the stress corrosion cracking (scc) using laboratory experimental data that related stress intensity factor (k) to crack growth rate (v). current analysis has been implicated on austenitic stainless steel in 42% chloride magnesium (mgcl2) at 154 oc and the results were in agreement with the experimental recorded data. the present analysis generates very beneficial information about the mechanical and environmental effects on the failure of specific environment and this information is difficult to be obtained from laboratory experiments. keywords: stress corrosion cracking, failure time prediction, 304ss, 42% boiling mgcl2 ةصیاغة تحلیلی : . . . . nomenclature: a: crack length a: constant ctod: crack tip opening displacement e: the base of natural logarithm e: young's modulus fem: finite element method (42 %) (154 oc) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 j: the j-integral k: the stress intensity factor ki: simultaneous stress intensity factor kic: fracture toughness kiscc: threshold stress intensity factor for stress corrosion cracking lefm: linear elastic fracture mechanics n: constant r: radius of plastic zone scc: stress corrosion cracking sgbem: symmetric galerkin boundary element method tf: failure time v: the total crack growth y: the yield strength : posson's ratio he applied stress introduction: the stress corrosion cracking (scc) is a time dependent crack growth caused by mechanical, electrochemical and metallurgical conditions. ability of predicting crack growth under scc conditions is important for safety analysis of structural components in different industries. abousayed et al. [abousayed, 1981] have proposed a procedure for prediction scc growth rates based on the determination of the crack tip opening displacement (ctod) by finite element methods. this procedure depends on the application of the stationary crack relation between ctod and the j-integral of the dbcs model to the work hardening material. they showed that crack growth rates are higher than the rates obtained from lefm analysis. smith [smith, 1985] has developed a methodology for prediction the growth rate of scc by obtaining an appropriate correlation between theory and experimentally determined relation that related k to v when lefm conditions are valid and when lefm conditions are not operative. the result of smith's analysis showed that the predicted relations between k and v for these two cases are different the result clearly exposes the limitations of lefm procedure for prediction scc growth rates. kosaki [kosaki, 1992] analyzed a reaction model to evaluate scc lives of stainless steel (304 type) in high temperature pure water by constant load. he obtained a certain correlation between scc life parameters. he also found that the dependency of the applied load on scc life by an expression in the form of a hyperbolic tangent functions. pauchard et al. [pauchaard, 2002] introduced a model for prediction of failure time of the glass fibers. according this model the time to failure (tf), of a glass fiber under a given stress loading is a function of: the strength of the fiber in an inert environment, fracture toughness, yield strength and the two constants a and n particular parameters describing scc crack growth rate depends on material and environmental. nikishkov [nikishkov, 2008] developed a computational procedure for modeling of crack growth under stress corrosion cracking (scc) conditions. he modeled the crack by the symmetric galerkin boundary element method (sgbem) and used a finite element method (fem) for stress analysis of the uncracked structural component. his analysis success to provide a crack growth criterion in the three-dimensional cases based on the j-integral vector. the main aim of this paper is to provide analytical expression to calculate the time to failure of the stress corrosion cracking on different stress levels by using laboratory experimental data. derivation of the scc failure time model: the theoretical model is based on introducing environmental parameters to the non-environmentally assisted cracking mode. the non-environmentally assisted cracking model was proposed by rice al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 and soenson and developed by smith to involve scc growth rates [smith, 1982]. the governor equation of this model is related the crack growth rate in j-integral term to the stress intensity by the form of: (1) where a: crack length, e: the base of natural logarithm, e: young's modulus, j is the j-integral, k: is the stress intensity factor, r: radius of plastic zone, y: yield strength, , and : posson's ratio (2) (3) where is the applied stress. for lefm concept j can be calculated from the following equation: (4) so dj/da in equation (1) can be replaced by and this leads to: (5) ) 2 ln( )1(4 . 2 222 ry ke e y y da dj )) 2 ln(sec( )1(8 22 ye y j )) 2 (tan 2 ln( )1(4 2 22 yr ea e y e k j )1( 22 da dk e k )1(2 2 ) 2 ln( )1(4 . )1(2 2 2222 ry ke e y y da dk e k 22 2 222 2 )1(4 )1(2 )1(4 ) 2 ln( y e da dk e k y e ry ke ) 2 exp() )1(4 exp() 2 ( 2222 2 da dk y k y e ry ke ) 2 exp() )1(4 exp( 2 222 2 2 da dk y k y e e ry k al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 substituting eq. (2) and (3) to eq. (5): (6) after rearrangement: (7) or (8) the last equation represents the mechanical contribution of the total crack growth rate of the scc. the well accepted procedure for prediction the failure time of the scc is to use laboratory experimental data that related stress intensity factor (k) to the crack growth rate (da/dt) by the form of v(da/dt)=akn based on linear elastic fracture mechanics (lefm) concept [smith, 1985]. he total crack growth can be calculated from the following equation: (9) where a and n are constants and v is the total crack growth of the scc. substituting eq. (8) into eq. (9) leads to: (10) in lefm concept there are two values of (k): k value below which scc will not occur that called threshold stress intensity factor for scc (kiscc), and k value above which rapid plastic ) 2 exp()) 2 ((tan 4 )) 2 ln(sec( 8 2 2 22 da dk y k y y y y ) 2 exp( )) 2 ((tan )) 2 (ln(sec 2 2 2 da dk y k y y )) 2 ((ln(sec )) 2 ((tan ln/) 2 ( 2 2 2 y y y k dk da dt dk y yy k ak n )) 2 ((ln(sec )) 2 ((tan ln2 2 2 2 dt dk y yy k akn )) 2 ((ln(sec )) 2 ((tan ln2 2 2 2 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fracture will occur that called fracture toughness (kic). then the time to failure (tf) at any value of stress intensity factor (ki) can be calculated from: (11) after integration failure time (tf) will become: (12) where ki is the stress intensity factor at any moment between kic and kscc i.e note that if the integrand has n=2 the expression for tf will contain natural (ln) terms. results and discussions: in this item the application of the proposed model to the austenitic stainless steels in boiling saturated magnesium chloride solution was discussed. the present analysis was applied to predict the failure time of sensitizing aisi 304 stainless steel in 42% chloride magnesium (mgcl2) at 154 oc, the practical case which is widely occurred in nuclear power and chemical plant components. the values of parameters that are needed for calculations are those considered in literature [sarvesh, 2010]. the calculated parameters for the current system from the literature are listed in table (1) and the environment's constants a and n are calculated from eq. (9) by setting (13) with vinitial=8.63x10-11 [rieck, 1986] for realistic solution to eq. (12) the value of the constant n is varying from 4 to 9 and for current system n=4.555 and a=1x10-42. after introducing these values to eq. (12) and taking the value of stress ratio ( ) varying from 0.56 to 0.76 as shown in figure (1) (to measure the effect of stress ratio on the failure time). figure (1) shows that the time to failure is highly depended on the stress ratio magnitude and when replacing the value of ki with the kiscc value to calculate the total failure time after introducing the value of stress ratio varying from 0 to unity the failure time can be drawn as a function of the stress ratio and the result can be shown in the figure (2). figure (2) shows that the failure time is a function of the stress value even though in fixed value of stress intensity factor the fact that emphasis that lefm concept cannot directly applied on the scc especially at high stress value and by using current analysis it can study the full time behavior against other scc parameter by obtaining the effect of crack growth rate on the failure time. ic i k k ntf dk y yay k dt )) 2 ((ln(sec )) 2 ((tan ln2 2 2 2 1 0 )2()2( 2 2 2 )) 2 ((ln(sec )) 2 ((tan ln ))2(2/( n i n icf kk y y nay t iciiscc kkk )ln( )/ln( iscc initial k av n al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 the calculated failure time (tf) as shown in figure (3) is highly depended on crack growth rate. figure (3) shows the relation between failure time (tf) and crack growth rate at kiscc value at the stress ratio ( 0.64 [sarvesh, 2010]. from figure (3) the failure time (tf) can be divided in to three stages as compared with the crack growth rate (v): stage (i) in which the failure time decreases rapidly from high to a moderate (tf) values, stage (ii) in which the failure time is decreased slightly at a moderate (tf) values, and stage (iii) at which the failure time is decreased rapidly from moderate to low (tf) values similar to the stage (i) vertical line. here it important to refer that many studied were held to emphasis the direct relation between the stress intensity factor (ki) and the stress crack growth (v) in the stress corrosion cases that also stated that the relation between (ki) and (v) is also divided in to three stages: stage (i) (initiation period), stage (ii) (propagation period) and stage (iii) (failure period) [smith, 1980 and 1984]. to understand this behavior the cracking rate (v) has been evaluated by two parameters (dki/dt) and (da/dki). these two parameters can be calculated from eqs. (11) and (8) respectively and figs.(4) and (5) show the effect of failure time on these two parameters. returning to the eq. (9) the two parameters (dki/dt) and (da/dki) are multiple by each other and that is mean values of these two parameters will specify the value of the total crack growth rate (v). from figures (4) and (5) it can concluded that stress corrosion crack is initiated by the effect of the parameter (dki/dt) that recorded by many studies as the environmental effect and since it's magnitude started from zero value at a life time lower than the starting life time of the (da/dki) parameter so this parameter will drive the other parameter (da/dki) that recorded by recent studies as mechanical effect on the total crack growth. after initiation region these two parameters will have approximately equal effect on the total crack growth (v) since they have approximately similar decay line at similar life times. at still low failure time near kic value it can see from figure (5) that fast failure initiated by the effect of the parameter (da/dki) because it's value decreases rapidly at a life time greater that the life time of (dki/dt) parameter. so (da/dki) parameter will drive the total crack growth to the failure region. these three conclusions are coincide with many other studies conclusion that stated that stress corrosion cracking initiated by the electrochemical effect of the environment and propagated by the conjoint effects of electrochemical and mechanical parameters and at last fast rapid mechanical plastic fracture caused the last failure. in other words, mechanical effect of the stress corrosion cracking will not started until the environment effect causes a defect in the material with a sufficient magnitude and this emphases why the (da/dki) parameter not initiated from zero value and this magnitude is specified by kiscc value. then stress corrosion cracking will continue at a regular rate until it reaches to a value that the material can't sustain the applied load and this value of applied load is limited by kic value. conclusions: a combined model has been developed to predict failure time of the stress corrosion cracking. present analysis based on introducing the environmental contribution of the total crack growth rate in to the non-environmental sub-critical crack growth relation. this work is a successful attempt to formulate the failure time of the stress corrosion cracking in a general formula that is not depending on the loading and shape factors. so this formula can be used to analyze any experimental data or to transfer k-v experimental data to k-tf data and vice versa. also present analysis show that the failure time is a function of the stress value even though in fixed value of stress intensity factor the fact that emphasis that lefm concept can not directly applied on the stress corrosion cracking phenomenon especially at high stress value. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 references: abousayed, i. s., ahmed, j., burst, f. w. and kanninen, m. f., 1981 " the numerical simulation of crack growth in weldinduced residual stress fields"14th natl. symposium on fracture mechanics, los angeles, june. akio kosaki, 1992 "analysis of stress corrosion cracking life based on reaction model" nuclear engineering and design 138 pp.239-249. gennadiy nikishkov, 2008 " sgbem-fem modeling of stress corrosion cracking" 16th pacific basin nuclear conference (16pbnc), aomori, japan, oct. 13-18, 2008, paper id p16p1159. pauchaard, v., grosjean, f., campionboulharts, h. and chateauminois, a., 2002 " application of stress cracking model to an analysis of durability of glass/epoxy composites in wet environments" composites science and technology 62 pp. 493-498. rieck, r. m., atrens, a. and smith, i. o., 1986 "stress corrosion cracking and hydrogen embrittlement of aisi type 304 austenitic stainless steel in mode i and mode iii" materials science and technology 2 pp. 1066-1072. sarvesh pal and singh raman, r.k., 2010 "determination of threshold stress intensity for chloride stress corrosion cracking of solution-annealed and sensitized austenitic stainless steel by circumferential notch tensile technique" corrosion science 52 pp. 1985-1991. smith, e., 1980 "some implications of recent developments in plastic fracture mechanics on stress corrosion cracking in engineering materials" materials science and engineering. 44 pp. 205-211. smith, e., 1982 "predicting stress corrosion crack growth rates at high stress levels" materials science and engineering. 55 pp. 97-104. smith, e., 1984 " the transition between stress corrosion crack growth and plastic fracture ii" engineering fracture mechanics vol. 20. no. 3, pp. 515-520. smith, e., 1985 "the inapplicability of linear elastic fracture mechanics procedures for predicting crack growth rates when plasticity is extensive" materials science and engineering. 70 pp. 197-204. table (1) scc parameters for aisi 304 ss in 42% mgcl2 at 154 oc kiscc (mpa m1/2) kic (mpa m1/2) y (mpa) e (gpa) 8.632 76.303 308 198 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0 stre ss ra tio = 0.56 stre ss ra tio = 0.68 stre ss ra tio = 0.76 time to failure tf (h) fig.1: ki vs. time to failure (tf) plots for current analysis system with different stress ratios k i( m pa .m 1/ 2 ) 0 2 4 6 8 10 12 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 stress ratio ( ) fig.2: the time to failure (tf) vs. stress ratio ( ) l og fa ilu re ti m e (h ) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 crack growth rate (m/s) x 106 fig.3: the time to failure (tf) vs. crack growth rate (v) at stress ratio of 0.64 l og fa ilu re ti m e (h ) -4 -3 -2 -1 0 1 2 3 4 0 0 .5 1 1 .5 2 2 .5 -4 -3 -2 -1 0 1 2 3 4 0 0 .0 1 0 .0 2 0 .0 3 0 .0 4 dki/dt in (mpa.m1/2/h) fig.4: the time to failure (tf) vs. stress intensity factor changing rate at stress ratio of 0.64 l og fa ilu re ti m e (h ) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 da/dki in ( mm/mpa.m1/2) fig.5: the time to failure (tf) vs. crack growth changing with stress intensity factor at stress ratio ( /y) of 0.64 l og fa ilu re ti m e (h ) 4 3 2 1 0 1 2 3 4 0 . 0 0 2 0 . 0 0 4 0 . 0 0 6 0 . 0 0 8 0 . 0 1 0 . 0 1 2 0 . 0 1 4 0 . 0 1 6 0 . 0 1 8 0 . 0 2 <dad1c8ed2e706466> ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١ الریفي في تحقیق التنمیة الریفیة المستدامة االستقراردور معاییر أ. د محمد علي االنباري م. م محمود عامر جابك جامعة بابل/قسم العمارة جامعة بابل/قسم العمارة mahmoodchabuk@gmail.com profdr_alanbari@yahoo.com ملخص البحث: تحقیق تحول واسع في بُنیة تعتبر التنمیة الریفیة المستدامة أستراتیجیة أساسیة لتطویر المناطق الریفیة، اذ إنھا تعمل على احتیاجات األجیال الحالیة وتطلعاتھا المستقبلیة. أن أھمیة وجود التنمیة المستدامة للمناطق المجتمع بجوانبھ المختلفة بشكل یُلبي أن أغلبھا تعتمد في معیشتھا على أستغالل األراضي ذات الموارد الطبیعیة الكثیفة، أن تحقیق التنمیة المستدامة الریفیة جاء بسبب یتطلب إستقرار سكان الریف في أراضیھم، وعند مالحظة الواقع الریفي في العراق بشكل عام فانھ یُعاني من مشاكل عدیدة أھمھا إن من أھم أسباب َعدم االستقرار الریفي ُضعف التخطیط .م زوال القرى وأندثارھاعدم االستقرار، وھجرة سكان الریف ومن ثُ الُمسبق من قبل أصحاب القرار والمصممین والمخططین أو ُضعف الخطط واألستراتیجیات المستقبلیة الفعالة التي تساھم في ییر أساسیة في تحقیق االستقرار الریفي النھوض بواقع اإلسكان الریفي، لذلك جاءت أھمیة البحث في تشخیص وتفعیل معا وإستخالص مؤشرات منھا یمكن قیاسھا ومقارنتھا مع واقع ریفي معین ومن ثم توضیح دور تلك المعاییر في تحقیق التنمیة الریفیة لتنمیة المستدامة. تضمن البحث أختیار واقع ریفي معین ضمن محافظة بابل كمنطقة للدراسة یضم قرى تتمیز بتوفر مقومات ا تم جمع المعلومات األساسیة عن طریق الزیارات المیدانیة والمقابالت . المستدامة ولكنھا تُعاني من عدم االستقرار بشكل دائم الشخصیة ومليء إستمارات أستبیان خاصة لتقییم المؤشرات من قبل سكان القریة وصوالً الى النتائج النھائیة التي تحدد مقدار الریفي ومن ثم أعداد مقترحات االستقرارؤشرات التي تم قیاسھا عند مقارنتھا مع المعاییر األساسیة في تحقیق الفجوة بین ھذه الم .وتصمیم الوحدة السكنیة للتطویر على مستوى تخطیط القریة الریفي. االستقرارمعاییر –الریفي االستقرار-التنمیة الریفیة المستدامة-المستقرات الریفیة-الكلمات المفتاحیة: اإلسكان الریفي the role of rural stability criteria in achieving sustainable rural development abstract: sustainable rural development consider as basic strategy to develop rural areas, as it works to achieve a major changes in different aspects of life rural community in order to meet the needs of current generations and their future aspiration, there is important rule of sustainable development for rural areas, because of these areas depend mainly on intensive natural resources in their lands. sustainable development can be achieved by stability of rural population in their areas. generally, in iraq we noticed that rural areas really suffers from many problems such as lack of stability, and emigration of rural people and then disappearance of these villages. the most important causes of instability are weakness of advance planning by decision-makers, designers and planners or weakness of future plans and strategies to develop the rural reality, so the importance of this research is to identify the criteria of achieving rural stability and to derive some indicators from it which can be measured and compared with a certain rural condition and then to clarify the role of these criteria in achieving sustainable rural development. this study include choosing a certain rural area located in babylon province consisting from many villages which have the important elements of sustainable development and disappearance of stability as a case study. data collection had been done by frequent visiting of the area of the study and making personal interviews with rural dwelling in order to fill a special questionnaire paper to evaluate the indicators by those dwellers to reach the final results which determine the gap between measured indicators when it compared with the criteria of achieving rural stability and then to prepare suggestion to improve the level of master planning and design of the dwelling units. ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٢ key-words: rural housing rural settlements sustainable rural development rural stability rural stability criteria. :المقدمة إن ھجرة السكان من الریف الى المدن أزداد بشكل كبیر في العراق وخاصة منذ النصف الثاني من القرن العشرین، إن أرقام الجھاز المركزي لإلحصاء في وزارة التخطیط العراقیة أشارت الى إنخفاض نسبة ، ١٩٤٧عام % حسب تعداد السكان في ٦٦.٣% بعد أن كانت تُشكل ٣٠الى ٢٠١٦سكان الریف في عام % في عام ٢٧وھنالك تنبؤات حسب اللجنة الوطنیة للسیاسات االسكانیة بأن تنخفض نسبة سكان الریف الى . لقد تناول العدید من المخططین والمعماریین القدامى والمعاصرین موضوع مشاكل اإلسكان واإلستقرار ٢٠٤٠ ي الذي صمم قرى طینیة تھدف الى إسكان الریفي ومن أبرزھم المخطط والمعماري المصري الشھیر حسن فتح الفقراء من أبناء الریف وكان لمشروع قریة القرنة التي أنجزت ولم یسكنھا ناسھا صدمة أثرت فیھ كثیراً، وفي إذ أنشأت مشاریع متعددة لسكن العوائل الفالحیة دوكسي أدسالعراق كان لبرنامج اإلسكان العراقي لدى مؤسسة واإلمام في مشروع المسیب الكبیر ولكن غالبیة العوائل الفالحیة تركت السكن الرشادتا على سبیل المثال قری الى عدم التوسع في إنشاء باقي القرى العصریة. لذلك ديأفیھا وعادت للسكن في مساكنھا الطینیة السابقة مما ان في مناطقھم وأن ال بتركز السك االھتماموخطط تطویر المناطق الریفیة على استراتیجیاتیجب أن تركز الضروریة الخدمات والمرافق توفیر تقتصر على تھیئة السكن الالزم لسكان الریف وإنما باإلضافة الى ذلك للمناطق الریفیة، لذلك فإن ھنالك التي تعمل على ربط االنسان الریفي ضمن البیئة المحلیة واالقلیمیة الحیویة ضرورة أساسیة في أن یكون االستقرار الریفي المخطط من أولیات استراتیجیات التنمیة الریفیة المستدامة من تتباین أھمیتھا أو تتفاعل أو معاییرخالل عملیة تطویر متكاملة. أن تحقیق االستقرار الریفي یرتبط بمجموعة ن البحث یطمح الى تشخیص ھذه المعاییر وتفعیل دورھا في تحقیق التنمیة الریفیة تتداخل مع بعضھا، لذلك فإ المستدامة، ومن ثم أعداد المقترحات التخطیطیة والتصمیمیة المناسبة للمنطقة الریفیة. مشكلة البحث: الریفي في تحقیق التنمیة الریفیة المستدامة في منطقة االستقرارتكمن مشكلة البحث في عدم وضوح دور معاییر الدراسة. ھدف البحث: الریفي من االستقراركان ھدف البحث ھو تشخیص وتفعیل مؤشرات من واقع حال القرى الریفیة وفقا لمعاییر أجل تحقیق التنمیة الریفیة المستدامة. فرضیة البحث: الریفي. االستقرارإن تحقیق التنمیة الریفیة المستدامة لواقع ریفي معین یتطلب أن تتوفر فیھ معاییر : rural settlementsالمستقرات الریفیة -١ تعتبر القرى من أقدم مراكز اإلستیطان واإلستقرار البشري عبر حقب ظل خاللھا اإلنسان متنقالً طلباً )، وتعرف المستقرات الریفیة بأنھا المناطق التي ٢٠١٢والراحة. (عبد الرزاق، للماء والكأل أو سعیاً لألمان تتصف بسیادة النشاط الزراعي والذي یعتبر الفعالیة اإلقتصادیة األساسیة باإلضافة الى فعالیات أخرى سان وتعرف أیضاً بانھا منطقة مسكونة من قبل االن )،mandal,2001. (كالصناعات والحرف الریفیة وغیرھا ). أن ١٩٩٨.(عبد هللا،االستقراریتفاعل في داخلھا مع الظروف البیئیة، الطبیعیة، اإلجتماعیة ولھ ھدف معین ھو معظم المستقرات الریفیة في مناطق عدیدة من العالم كان للظروف البیئیة األثر األكبر في نشؤھا وتطورھا عبر في توزیع المستقرات في المناطق الریفیة غیر المسكونة الزمن الى أن بدأ اإلنسان یعتمد على أسلوب التخطیط ویغیر من مواقع المستقرات المسكونة مما یؤكد على أھمیة التخطیط العام في سبیل تحسین الظروف المعیشیة األرض والموارد المتوفرة استثماروإستثمار الموارد الطبیعیة الموجودة في البیئة وتنظیم العالقة بین أنواع إنتاجیة التربة اختالف)، ومنھم من یعتقد إن (moseley, 2003 .لإلنسان واالجتماعیة االقتصادیةجات والحا ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣ فیھا یعتبر من العوامل التي نتجت عنھا الروائیةوتباین توزیعھا ومدى قرب المناطق الزراعیة عن مصدر المیاه طور الحدیث المتالحق و كذلك ظھور )، ومنھم من یرجع العوامل الى الت٢٠٠٦المستقرات الریفیة.(كمونة، والتي أدت الى التوازن بین الموارد البشریة والطبیعیة والتي تعتبر من واالجتماعیةمرحلة التنمیة التخطیطیة ). ٢٠٠٦أھم المحددات في ھذه التنمیة.(الشمري، :sustainable rural developmentالتنمیة الریفیة المستدامة -٢ ومن وكثر، زاد ینمو، أي فھو) نمو (من مشتقة التَّنمیة، مفھوم حول واإلصطالحات التعریفات تعددت حجمھ، ھناك فرق بین النمو والتنمیة فالنمو یعني بأن الزیادة في زاد أي نامیاً، الشيء، جعلھ تنمیة) نمي( الطبیعیة تكون بدون تدخل، أما التنمیة فتعني بأن التغییر اإلیجابي یكون عن طریق التدخل، والذي یكون بشكل برامج مدروسة ومبنیة على أسس التخطیط العلمي إلحتیاج السكان وصوالً الى األھداف المرجوة لتنمیة الت المطلوبة على أن یكون ھناك إشراف على ھذه البرامج من قبل ھیئات وطنیة رسمیة وشعبیة، أما المجا المفھوم العلمي فیتناول التنمیة بشكل شامل لكل الجوانب اإلیجابیة أعتماداً على الطاقات واإلمكانیات المحلیة. لمبادئ التكاملیة التي تنطوي على الطاقة، ). أن التنمیة المستدامة تعرف بأنھا مجموعة شاملة من ا٢٠٠٩(قشوع، وتكامل السیاسات، و أن االقتصادیةوالتنمیة االجتماعیةوالنظم اإلیكولوجیة البیئیة، واإلدارة الحضریة والعدالة حلول فعالة یمكن أن تتحقق بطریقة تعاونیة، األمر الذي یتطلب األخذ بعین اإلعتبار تداعیات مستقبلیة من وھي لیست جمیعھا مؤاتیھ، أن التنمیة المستدامة یمكن أن تقدم الفرص والتحدیات –تي تتخذ الیوم القرارات ال لقد كان أول تعریف لمفھوم التنمیة المستدامة بالمعنى الحدیث ).rosa, 2010(ولكن األھم من ذلك الحلول. بانھا" التنمیة التي تفي ١٩٨٧ي عام ف بروند الندوالبیئي في تقریر واالجتماعي االقتصاديالذي یقر بالتقارب اللجنة طرف من ُعّرفت كما .باحتیاجاتھاالحاضر دون المجازفة بقدرة أجیال المستقبل على الوفاء باحتیاجات تلبیة في القادمة األجیال قدرة تمس أن من دون الحالیة األجیال احتیاجات تلبي بأنھا "المستدامة العالمیة للتنمیة ). أما التنمیة الریفیة المستدامة فتعتبر الریف والتنمیة الریفیة واحده من ٢٠١٤ جمال الدین،(".احتیاجاتھا المصطلحات المثیرة للجدل بین التنمویین الباحثین وذلك نظراً ألنھا تھدف الى تطویر الحیاة الریفیة والسكان، عتبر التنمیة الریفیة جزءاً مھماً من خطط فالتنمیة تعزز االعتماد على الذات وھي من اإلنسان ولھ وتعود علیھ، تُ الدولة في التنمیة الشاملة وذلك ألن سكان الریف یُشكلون نسبة كبیرة من أعداد السكان. (الھیتي وأبو . وكذلك یطلق علیھا أسم التنمیة القرویة وھو مفھوم ُمعقد وُمركب ال یشتمل على مجاالً أو جانباً )٢٠٠٠سمور، والثقافیة والعمرانیة والبیئیة، بمعنى إنھا تھدف الى واالقتصادیة االجتماعیةكل الجوانب واحداً وانما یشمل لألجیال واستدامتھاتحسین معیشة سكان الریف وتطویر مھاراتھم المعرفیة والتقنیة مع ضرورة تثمینھا فَت االمم المتحدة عملیة التنمیة الریفیة بأنھا :٢٠٠٩، حموضيالالحقة.( االقتصادي"عملیة التغیر -). وَعرَّ تحقیق أھداف التنمیة الشاملة، والقائمة من أجلالتي تتضمن وتستوجب تغییر المجتمع الزراعي واالجتماعي على قدرات السكان وحاجاتھم، وتكون أھدافھا ضمن أھداف التنمیة القومیة، والتي تعطي األولویة في تقلیص مشاركة السكان، وخاصة ذوي المستوى المعاشي واعتماداد، بین األفر واالجتماعي االقتصاديالتفاوت َف البنك الدولي التنمیة الریفیة بأنھا: "أستراتیجیة مخططة لتحسین الحیاة االقتصادیةالمنخفض" وقد َعرَّ للسكان الذین یجب شمولھم بمنافع التنمیة، وھم المزارعین الصغار، ومستأجرو األرض، والذین ال واالجتماعیة واالقتصادیة االجتماعیةكون األرض" وعلى ھذا األساس أن التنمیة المستدامة تؤدي الى تھیئة األوضاع یمل والثقافیة والعمرانیة وغیرھا في المناطق الریفیة، وھذه التطورات باألساس تھدف الى تطویر الفرد، وقدراتھ، ي و مكافحة ھجرة الریف الى المدینة وتوزیع القوم االقتصاد، وتعزیز االجتماعیة -االقتصادیةوتحقیق الرفاھیة من خالل أزالھ الفقر ورفع االقتصادیةالثروات والسطلة بین األفراد وتحقیق التكامل بین مجمل القطاعات مستوى اإلنتاج والدخل وتوزیع فرص العمالة المنتجة وزیادة نصیب الفرد الریفي من الخدمات باإلضافة الى . مما (cloke,2010)ریف والمدینة عن طریق قنوات التعامل والتأثیر المتبادل فیما بینھم.تقلیل الفوارق بین ال تتعامل مع مشاكل الریف كافة مع التركیز بشكل أساسي على ذكر أعاله فانھ یمكن تعریف التنمیة الریفیة بانھا ي جمیع جوانب الحیاة اإلحتیاجات األكثر فقراً بقصد أحداث تغیرات مطلوبة ومرغوبة من قبل السكان وف .والثقافیة وغیرھا واالجتماعیة االقتصادیة :rural stabilityالریفي االستقرار -٣ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٤ الریفي مرحلة مھمھ في تطور المجتمعات البشریة ألنھ یمثل النواة األولى لإلستقرار االستقراریعتبر البشري والتي أمتازت ببساطة الحیاة وبشكل عام اإلتجاه الى ممارسة مھنة أساسیة ھي الزراعة باإلضافة الى التي تقع ضمن رقعة الریفي أیضاً بانھ "تلك المنظومة االستقرار). ویعرف ٢٠٠٨مھن ثانویة مختلقة.(علي، جغرافیة معینة لإلقلیم الریفي الخاص بالمدینة وتربطھا عالقات سكانیة وظیفیة وخدمیة مع بعضھا البعض ومع ). أن إستقرار اإلنسان في بیئة ١٩٩٩المدینة ضمن ما ھو متاح من إمكانیات وموارد بشریة وطبیعیة".(الطاھر، نتیجة إلرتباطھ باألرض وإستقراره علیھا وإستثمارھا ینتج نوع من معینة یعني بأنھ أصبح متكیفاً ألجوائھا و االستقراروفي ضوء ما تقدم یرى الباحث بان .)٢٠١٢وغیرھا. (عبد الرزاق، واالقتصادیة االجتماعیةالعالقات وسكن لمعیشة الضروریة یھیئ البیئة أنھ حیث التنمیة الریفیة، تخطیط في األساسیة المفاصل یعد أحد الریفي التي تطلبھا. الضروریة الخدمات وتوفر األنسان المعاییر األساسیة في تحقیق االستقرار الریفي: -٤ الریفي، وكما یلي: االستقرارن تتوفر في المنطقة الریفیة لتحقیق أمن المعاییر التي یشترط تم تشخیص مجموعة الحصول على قریة ال تمتلك مورداً مائیاً أو ال یقع نادراً ما یمكن -: water resourcesالمائیة الموارد :أوالً مورد مائي بالقرب منھا، أن األمر الطبیعي بالنسبة لإلستقرار الریفي ھو أن القرى تتواجد أما بالقرب من األنھار والبحیرات أو العیون نظراً ألھمیة الماء للري واألغراض المنزلیة وسقي الحیوانات وصید ).٢٠٠٨األسماك.(علي، ال یمكن العیش واإلستقرار في أرض غیر منتجة، لذلك یجب أن یختار -:land productالمنتجة ثانیا: األرض سكان الریف األرض التي تتوفر فیھا درجة معینة من الخصوبة بحیث یمكن لھا أن تعیلھم، باإلضافة الى إن عدد ).٢٠٠٨. (علي،األفراد الذین تعیلھم األرض ایضاً یحدد حجم المستوطنة الریفیة إن درجة صالحیة الموقع الذي تبنى علیھ المستوطنة الریفیة یُؤثر -:location efficiency ثالثا: كفاءة الموقع على إستقرار السكان في مكان المستقرة الریفیة، لذلك یجب أن تكون المستقرات الریفیة في مواقع ال تتأثر بمیاه فضة عند منعطفات األنھار وإنما یجب أن تقع في األرض السھلیة الفیضان المتكرر أو عند األماكن المنخ المرتفعة عند ضفاف األنھار، وكذلك یجب أن ال تقع في األماكن القریبة من مناطق الطمر الصحي أو المناطق (cloke,2010). الموبوءة باألمراض و المستنقعات المائیة الملوثة. یُعتبر موضوع الخدمات ذو أھمیة كبیرة بالنسبة لإلستقرار الریفي : services provideرابعا: توفر الخدمات إذ ال یمكن ضمان أستمرار تسییر الحیاة الیومیة من دون توفر الخدمات الالزمة للعیش داخل المنطقة الریفیة أو (cloke,2010). بالقرب منھا وعلى كافة المستویات التعلیمیة والصحیة والعمرانیة والبیئیة وغیرھا. من الالزمة للحیاة الیومیة : إن أمكانیة الحصول على الموادprovide resourcesخامسا: توفر المواد األولیة وبناء المستقرة الریفیة، االستقراراألعتبار األول عند التفكیر في داخل القریة أو بالقرب منھا یجب أن تكون في باإلضافة الى أمكانیة تشكیل التربة المالئمة بعد تحویلھا الى طین بأشكال صالحة لألستعماالت المختلفة، وكذلك ).٢٠٠٩االعشاب واالحراش.(صعب، توفر مواد أخرى كالقصب والبردي أو أي نوع من ال یبلغ الحد األدنى الذي یؤمن الحاجات : تعني بأن یكون معدل دخل الفردincomeمستوى الدخل سادسا: الغذائیة وغیر الغذائیة األساسیة وكذلك عدم أرتفاع نسبة البطالة بین سكان القریة إذ إن أنخفاض مستویات الدخل وأرتفاع نسبة البطالة تدفع سكان القریة للھجرة أو الخروج من القریة للحصول على فرص .(cloke,2010)للعمل. : األنتماء ھو العمود الفقري للجماعة وبدونھ تفقد الجماعة تماسكھا، أن الشعور belongingماء األنت سابعا: أھمھا العادات والتقالید واألعراف الریفي االستقرار أتجاھات رسم في متمیز دور باألنتماء االجتماعي لھ ).٢٠٠٩.(صعب،اإلجتماعیة تتمثل في قدرة سكان القریة على أمتالك وأستخدام األسالیب: techniques used: التقنیات واألسالیب ثامنا الزراعیة الملكیة وحجم الزراعي اإلنتاج ونمط المتطورة اإلرواء الزراعي وطرق حدیثةالزراعیة ال والنظم ).٢٠٠٩وكذلك اآللیات الحدیثة والتي تُساھم في زیادة اإلنتاج الزراعي وزیادة كفاءتھ.(صعب، : تتمثل في قابلیة القریة على التوسع وإمكانیة نمو القرى الریفیة extension abilityسعقابلیة التو تاسعا: بمختلف األتجاھات وعدم وجود عوارض أو حواجز تمنع ذلك األمتداد باتجاه محدد، ومن ھذه العوارض ).٢٠٠٩االنھار، البساتین، الجبال، البقع المائیة وغیرھا.(صعب، ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٥ سفوح : تؤثر العوامل المناخیة في بناء المستقرات الریفیة مثل عندsuitable climateعاشرا: مالئمة المناخ في المناطق السھلیة و الجبال ظل في الباردة الریاح من محمیة تكون للدفيء وأن طلبا الشمس تواجھ التي الجبال والجافة وعلى الشمس في تُبنى المستقرات الریفیة بشكل یساعد في حصولھا على الظل في السھول الحارة ).٢٠٠٨علي، (السھول الواقعة في المناطق الباردة. منھجیة البحث: تم إعتماد المنھج الوصفي التحلیلي مع منھج الدراسة المیدانیة، إذ قام الباحث بتشخیص معاییر یفیة المستدامة ومن ثم الریفي (النموذجیة) التي یجب أن تتوفر في المنطقة الریفیة لتحقیق التنمیة الر االستقرار إشتقاق مجموعة مؤشرات من تلك المعاییر، ومن خالل تقییم ھذه المؤشرات من قبل سكان القریة بإستخدام أستمارة اإلستبیان من أجل تقییم الواقع الریفي في المنطقة (واقع الحال) ومن ثم مقارنھ نتائج تقییم ھذه لفجوة والتي على أساسھا نقوم بإعداد المقترحات وبدائل التطویر المؤشرات مع المعاییر األساسیة لتظھر لنا ا لمنطقة الدراسة وأختیار البدیل األفضل وأعداد المخططات التفصیلیة للمنطقة. : منطقة الدراسة تم اختیار منطقة تقع في محافظة بابل في المنطقة الوسطى من العراق كمنطقة للدراسة، والتي تتمیز بكثرة األراضي الریفیة التي تنتشر فیھا أعداد كبیرة من القرى، أن اختیار ھذه المنطقة جاء بسبب أھمیتھا السكان، تقع منطقة استقرارم من عدم باعتبارھا تقع في منطقة السھل الرسوبي الخصب ولكنھا تُعاني بشكل دائ ٢كم ٢٠كم تقریبا، تبلغ مساحة منطقة الدراسة حوالي ١٢الدراسة الى الجنوب من مركز مدینة الحلة بحوالي )، یوجد مشاریع مائیة في المنطقة ١تقریبا، تتكون المنطقة من خمسة قرى ریفیة كما موضح في الشكل رقم ( وجورة)، تقع المنطقة على محاذاه الشارع الرئیسي الذي یربط ھجینیةمشروع ( تنبع من شط الحلة وھما كل من دیوانیة، بالقرب من المنطقة تقع معامل صناعیة ھي معمل المشروبات الغازیة ومعمل -بین مدینتي الحلة مام ) ومقام األ٢عدد ( ابتدائیةاالعالف. تتكون المنطقة من بیوت سكنیة موزعة بطریقة عشوائیة و مدارس ). أن القرى وأعداد أفرادھا وعدد البیوت السكنیة موضح بالجدول رقم ٢الخضر(ع) ومسجد ومستوصف عدد ( )١.( تقییم مؤشرات واقع منطقة الدراسة التي تركز على االستقرار الریفي: رة تم جمع المعلومات من خالل الزیارات المیدانیة المعدة من قبل الباحث وأعداد األسئلة في أستما ). تم أختیار العینات البحثیة بصورة ٣الریفي المشار الیھا في الفقرة رقم ( االستقراراإلستبیان في ضوء معاییر % من عدد سكان كل ١٠عشوائیة من بین سكان المنطقة الریفیة، أما عدد أفراد العینة فتم أختیار نسبة مقدارھا یكون لدیھم درایة بواقع القریة ویسكنوھا من مدة سنة حتى ٣٠قریة، والذین تتراوح أعمارھم ما فوق ال للحصول على نتائج أكثر دقة لتقییم واقع حال القرى في منطقة الدراسة. وضعت طریقة التقییم في ثالث تقییمات ھي (نعم) وتعني إن المؤشر متوفر في المنطقة بشكل یُرضي في المنطقة ولكن لیس بالشكل المطلوب لدى سكان القریة، والتقییم (الى حد ما) وتعني أن المؤشر متوفر السكان، أما التقییم (ال) فتعني أن المؤشر غیر متوفر أو ال یُرضي سكان المنطقة. وكما موضح في الملحق رقم )١.( :النتائج استناداً الى تقییم األفراد من سكان المنطقة الریفیة وحسب األسئلة المعدة من قبل الباحث في أستمارة اإلستبیان :تبین ما یلي ) التي تمتلك أكبر عدد من السكان بین القرى في منطقة الدراسة حصلت على أكبر عدد ١أن القریة رقم ( ) التي تمتلك أقل عدد سكان بین القرى ٥) والقریة رقم (٤م (من المؤشرات ذات التقییم (نعم)، أما القریة رق ).٣فحصلت على أقل عدد من المؤشرات ذات التقییم (نعم). وكما موضح في الجدول رقم ( ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٦ یعتبر أن المؤشرات (توفر الخدمات، مصدر الماء، مستوى الدخل) حصلت على أقل نسب تقییم، لھذا الالزمة و أنخفاض مستوى الدخل من أبرز المشكالت التي یعاني منھا نقص مصادر الماء وعدم توفر الخدمات سكان المناطق الریفیة وتضعف من أمكانیة االستقرار الریفي. أن المؤشرات (االرض المنتجة، توفر المواد االولیة، مالئمة المناخ) حصلت على أعلى نسب للتقییم في بصالحیة األرض وتوفر المواد األولیة والمناخ المالئم للسكن فان المنطقة الریفیة تمتاز منطقة الدراسة، لھذا ).٤. وكما موضح في الجدول رقم (واإلستقرار وممارسة مھنة الزراعة أن معدل نسب التقییم الكلیة لكافة المؤشرات في منطقة الدراسة ولكافة القرى كان بالنسبة للتقییم (نعم) %)، أما بالنسبة للتقییم ٢٨تقییم (الى حد ما) فكان معدل نسب التقییم (%)، أما بالنسبة لل٤٨معدل نسب التقییم ( ).٢) والشكل رقم (٤%). كما في الجدول رقم (٢٤(ال) فكان معدل نسب التقییم ( مناقشة نتائج تقییم المؤشرات: من خالل مالحظة نسب تقییم المؤشرات تبین ما یلي: المصدر المائي: أنھ بالرغم من تواجد مشاریع روائیة في المنطقة (مشروع جوره ،مشروع ھمینیھ )، -١ الروائیة% ال) وھذا یعني وجود ضعف في كمیات المیاه ٤٠% الى حد ما) و(٦٠إال أنھ كانت نسب التقییم ( لألراضي الزراعیة وخاصة في فصل الصیف. % نعم) وھذا یعني أن االراضي في منطقة ١٠٠ا المؤشر(األرض المنتجة: كانت نسب التقییم لھذ -٢ الدراسة ھي أرض خصبة صالحة للزراعة. كفاءة الموقع: في ھذا المؤشر جاءت نسب التقییم بشكل متفاوت بین القرى، وھذا بسبب وجود مصدر -٣ لملوثات في تلوث بالقرب من المنطقة وھي (مشروع معمل المشروبات الغازیة الصناعي) الذي یتسبب برمي ا ) األقرب الى ١الجداول القریبة من المنطقة مما یتسبب بانتشار الروائح الكریھة، لذلك نالحظ أن القریة رقم ( ) ٤) فكانت تقییماتھا (الى حد ما)، أما القریة رقم (٣) و(٢المشروع الصناعي كان تقییمھا (ال)، والقریة رقم ( مؤشر فیھا (نعم). ) البعیدة عن مصدر التلوث كان تقییم ال٥و( % ال) وھذا ینطبق على جمیع ١٠٠توفر الخدمات: نالحظ أن تقییم سكان المنطقة لھذا المؤشر كانت ( -٤ القرى الریفیة في المنطقة وھذا ما یؤشر أن المنطقة تتمیز بنقص كبیر جداً في مستوى الخدمات و لكافة المستویات. %) وھذا ١٠٠خصوص المواد الالزمة للحیاة الیومیة (توفر المواد االولیة: كانت نسب تقییم (نعم) ب -٥ یعني أن أغلب المواد الضروریة للحیاة الیومیة متوفرة في المنطقة أو بالقرب منھا. %) لتقییم (ال) وھذا یعني أن ٤٠%) كانت لتقییم (الى حد ما) ونسبة (٦٠مستوى الدخل: أن نسبة ( -٦ ات الدخل وھذا ما جعل الكثیر منھم یتجھ للعمل في المدینة معظم سكان المنطقة یعانون من أنخفاض في مستوی لكسب الرزق وخاصة في فصل الصیف. % نعم) وذلك ألن معظم سكان المنطقة یتمیزون بقوة ١٠٠األنتماء: كانت نسب تقییم ھذا المؤشر ( -٧ التي تجمع بین أبناء ةاالجتماعیاألنتماء الى المنطقة التي یعیشون فیھا ویرجع ذلك الى قوة العالقات والروابط المنطقة الریفیة. ) كان تقییم المؤشر فیھا ١األسالیب والتقنیات: تتفاوت نسب تقییم ھذا المؤشر فنالحظ أن القریة رقم ( -٨ ) فكان التقییم فیھا (ال) ویرجع ٥) فكان التقییم فیھا (الى حد ما) أما القریة رقم (٣) و(٢(نعم) والقریة رقم ( أبتعاد القرى عن الشارع الرئیسي.السبب في ذلك الى ) ألن سكان القریة لدیھم ٣) و(٢) و(١التوسع والنمو: كان تقییم المؤشر (نعم) بالنسبة للقریة رقم ( -٩ واالمكانیة للتوسع وبكافة األتجاھات وھناك زیادة نسبیة في أعداد السكان. والتقییم (الى حد ما) بالنسبة الرغبة أقل من حیث الرغبة واالمكانیات. ) ألنھا٥) و(٤للقریة رقم ( %) وھذا یعني أن مناخ ١٠٠مالئمة المناخ: كانت التقییمات في جمیع القرى لھذا المؤشر (نعم) وبنسبة ( -١٠ المنطقة مناسب للعیش واإلستقرار والزراعة و لكافة المواسم والفصول. ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٧ إعداد مقترحات وبدائل التطویر في منطقة الدراسة: الریفي في االستقرارمن أجل تطویر الواقع الریفي وسد الفجوات التي أبرزتھا عملیة تقییم مؤشرات )، جاءت مقترحات االجتماعیة، االقتصادیةسبیل تحقیق التنمیة الریفیة المستدامة بجوانبھا األساسیة (البیئة، -ة مناطق رئیسیة ھي: منطقة صناعیةالتطویر في منطقة الدراسة من خالل تخطیط المنطقة الریفیة الى ثالث الریفي من خالل توفیر الخدمات، توفیر المواد األولیة، رفع مستوى الدخل، األسالیب االستقرارتجاریة (تعزز والتقنیات). ومنطقة زراعیة (تخدم المجال البیئي وحفظ الموارد الطبیعیة من خالل زیادة إنتاجیة األرض، توفر مالئمة المناخ)، ومنطقة سكنیة مالئمة للعیش واإلستقرار (تخدم المجال اإلجتماعي وتزید المیاه، كفاءة الموقع، من األنتماء ولھا القابلیة على التوسع المستقبلي)، لذلك تم أعداد ثالثة مقترحات على أن یتم بعدھا أختیار البدیل األكثر مالئمة لمنطقة الدراسة. الصناعیة) مركزیة وتقع في منتصف المسافة -كون الفعالیات (التجاریة): تخطیط المنطقة بحیث ت١مقترح رقم ( التي تجمع بین القرى الریفیة ومن حولھا تأتي المنطقة السكنیة ثم المنطقة الزراعیة. ): تخطیط المنطقة الى مجامیع تضم كل مجموعة قرى متجاورة مع بعضھا البعض بحیث كل ٢مقترح رقم ( صناعیة) مركزیة باإلضافة الى منطقة سكنیة ومنطقة زراعیة لكل -(تجاریة مجموعة تحتوي على منطقة مجموعة. عدم اإلعتماد على التخطیط المركزي وإنما یكون المنطقة السكنیة بمحاذاة ضفاف المیاه ):٣مقترح رقم ( الصناعیة بمحاذاة الشارع الرئیسي الذي یصل الى المنطقة -(المشاریع اإلروائیة)، وأن تكون الفعالیات التجاریة الریفیة، اما المنطقة المتبقیة فتكون عبارة عن مناطق زراعیة. البدیل األفضل وأعداد مخططات تفصیلیة للمنطقة:أختیار ) نالحظ أن ھناك صعوبة ١من خالل دراسة المقترحات في أعاله تم مالحظة انھ بالنسبة للمقترح رقم ( وذلك بسبب قوانین ملكیة األرض باإلضافة الى تباعد في عملیة تخطیط منطقة مركزیھ موحدة لجمیع القرى ) نالحظ أن ھذا المقترح یخدم ٢ططة للوصول الیھا، اما بالنسبة للمقترح رقم (القرى وعدم توفر الطرق المخ التجمعات الریفیة ذات المساحات الكبیرة جداً والمتباعدة وھذا ال ینطبق مع منطقة الدراسة في البحث، أما بالنسبة سة بسبب عدم الحاجة الى تغییر ) فأننا نالحظ انھ األكثر مالئمة للتطبیق بالنسبة الى منطقة الدرا٣للمقترح رقم ( ملكیات األراضي باإلضافة الى أن المسافات متقاربة بین القرى، و بناءاً على ذلك تم وضع مخططات مقترحة لتطویر المنطقة على مستوى كل من: أوال: على مستوى تخطیط المنطقة: الثة أجزاء بحیث یكون الجزء ) أعاله تم تقسیم المنطقة الریفیة الى ث٣حسب ما جاء في المقترح رقم ( التجاریة فتكون بمحاذاة الشارع –وجورة)، أما المنطقة الصناعیة ھجینیة( الروائیةالسكني یطل على المشاریع الرئیسي بالقرب من مشروعي معمل المشروبات الغازیة ومعمل األعالف وغیرھا، أما المنطقة المتبقیة فتكون ضمن المنطقة الریفیة بشكل عام الفعالیات األساسیة التالیة: مضیف شیخ أراضي زراعیة، مع مراعاة ان تت ، سوق محلي، مسجد، مركز صحي ( رعایة صحیة أولیة)، مستوصف بیطري، مخزن ابتدائیةالعشیرة، مدرسة ).٢حبوب، مرآب سیارات موزعھ في داخل المنطقة الریفیة. وكما موضح في الشكل رقم ( ثانیا: على مستوى تصمیم الوحدة السكنیة: تم األقتراح بان یتم تخصیص قطعة أرض ذات ابعاد مناسبة لكل عائلة ضمن حدود األراضي الخاصة بھا في الجزء السكني المقترح، مع مراعاه أن یتم توفر األمور التي تالئم سكان المنطقة الریفیة وكما یلي: نزلیة و كحظیرة الحیوانات، مضیف رجال، غرف نوم، مطبخ، معیشة، فناء داخلي یستخدم لألغراض الم ).٣صحیات، وكما موضح في الشكل رقم ( اإلستنتاجات: تم في البحث التقصي عن أھم المعاییر األساسیة في تحقیق االستقرار للمواقع الریفیة والتي من خاللھا ریفیة المستدامة.یمكن تقییم مدى مالئمة الموقع الریفي لتحقیق التنمیة ال الریفي على أختبار واقع ریفي معین، إذ كلما االستقرارأظھرت النتائج الدور الفعال الذي تلعبھ معاییر تكون نسب تقییم سكان الریف للمؤشرات أعلى كلما زادت إمكانیة إستقرار السكان في مناطقھم وبالعكس. ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٨ صعوبات على المستوى التخطیطي والتصمیمي في عدم وجود تخطیط ُمسبق للمنطقة الریفیة یؤدي الى أجراء بدائل التطویر المقترحة على واقع حال المنطقة الریفیة وخاصة من حیث توزیع البیوت السكنیة و توزیع ملكیة األراضي الزراعیة بین السكان. ار من صالحیة أظھرت النتائج إن المنطقة الریفیة تمتلك أھم مقومات البیئة الطبیعیة للسكن واإلستقر األرض وتوفر المواد األولیة والمناخ المالئم ولكنھا تعاني من مشاكل أساسیة تدفع السكان الى عدم االستقرار أھمھا ضعف كمیات المیاه الالزمة وضعف مستوى الخدمات الضروریة للحیاة أضافة الى أنخفاض في مستوى الدخل لألفراد. ارع الرئیسي للمنطقة الریفیة یكون بشكل أكبر من القرى البعیدة إن أعداد سكان القرى القریبة من الش عنھ وھذا یعود الى سھولة ربطھا بالمناطق المجاورة وامكانیة تزویدھا بالخدمات الالزمة لدیمومة الحیاة فیھا. :التوصیات داد أستثمار المعرفة العلمیة التي وفرھا البحث، وتشجیع المعماریین والمخططین على ضرورة أع دراسات وبحوث تكمیلیة بالشكل الذي یؤدي الى أعتماد معاییر وأسس ترسي عن طریقھا أبعاد التنمیة الریفیة المستدامة بجوانبھا المختلفة وبصورة تكاملیة. للمناطق الریفیة تمكن المصمم االستقرارضرورة تطویر وأعداد معاییر تفصیلیة متكاملة لتحقیق ع الریفیة للوصول الى األستدامة المنشودة.والمخطط من تقییم المواق ضرورة أن یتم التخطیط للتنمیة الریفیة من ضمن تخطیط التنمیة الوطنیة الشاملة ألن التنمیة الریفیة یمكن أن تساھم في النھوض بقطاع مھم من قطاعات المجتمع وبالتالي یمكن القضاء على مشاكل الریف. یة الحاجات األساسیة للمجتمع الریفي وحسب أولویتھا في التنفیذ بحیث یجب أن تلبي برامج التنمیة الریف تكون مشاریعھا األولى متماشیة مع الضرورات التي یعبر عنھا سكان المناطق الریفیة المراد تنمیتھا عن طریق معالجتھا التعرف الى المشاكل التي یعاني منھا المجتمع الریفي وتحدیدھا بصورة دقیقة ووضع الخطط الالزمة ل وتنفیذھا على وفق أولویتھا. یجب أن تتوفر اإلحصائیات والمعلومات الكاملة عن القرى الریفیة من حیث رسم الخرائط التفصیلیة للمناطق الریفیة وعمل اإلحصائیات الكاملة عن أعداد السكان والدور السكنیة فیھا وغیرھا. ریفیة وضمن مراحلھا من أجل رفع قدراتھم وتطویر یجب إستشارة وإشتراك األھالي في عملیة التنمیة ال المناسب والمالئم لھم لكي تكون الفائدة عامة وشاملة وأكثر ثباتاً. قابلیاتھم وكسب ثقتھم بأختیار المصادر: أبو زنط، ماجدة أحمد/سمحة، موسى، تخطیط التنمیة اإلقلیمیة في شمالي الضفة الغربیة فلسطین، ٢٠٠٢. د.ناصر صالح، النمو السكاني والتطور العمراني للمدن العربیة المعاصرة، جامعة بغداد، الشمري، ٢٠٠٦. الطاھر، ھیفاء عبد الكریم،" أثر الدخل في نمو وتطویر المستقرات الریفیة"، رسالة ماجستیر، المعھد .١٩٩٩العالي للتخطیط االقلیمي والحضري، جامعة بغداد، الریفیة"، عمان، االردن، والتنمیة الریفي االستیطان أبو سمور، "جغرافیةالھیتي، صبري فارس وحسن .٢٠٠٠دار صفاء للنشر والتوزیع، ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٩ جمال الدین، میمون، " الوقف والتنمیة المستدامة: دراسة تحلیلیة"، مجلة العلوم اإلقتصادیة والتسییر .٢٠١٤والعلوم التجاریة، جامعة المسیلة، الجزائر، ، لجین عباس، "التنمیة الریفیة المستدامة" دراسة في استقرار ونمو المستقرات الریفیة قدمت حموضي . ٢٠٠٩الى المعھد العالي للتخطیط الحضري واالقلیمي بجامعة بغداد، صعب، د. عبد الرزاق أحمد سعید، "المستقرات الریفیة في العراق (القریة الریفیة)، " دراسات تربویة .٢٠٠٩نیسان، العدد السادس، الطینیة في والمستوطنات والتصمیمیة للمباني التخطیطیة ،"الخصائص كمال د نجیل.م.الرزاق، أ عبد .٢٠١٢)، ٢٥العراق"، مجلة المخطط والتنمیة، العدد ( عبد هللا، نصیر ابراھیم،" تحلیل العوامل المؤثرة على كفاءة استخدام مبدأ وحدة الجیرة في تخطیط .١٩٩٨الریفیة، رسالة ماجستیر، جامعة بغداد ،المستقرات علي، تغرید حامد، االستقرار الریفي في العراق دراسة في االستقرار الریفي في ناحیة كبیسة، مجلة .٢٠٠٨)، جامعة بغداد، ١٨التخطیط والتنمیة، العدد ( سطینیة"، رسالة ماجستیر قشوع، منال محمد،" إستراتیجیات التنمیة الریفیة المتكاملة في األراضي الفل .٢٠٠٩في كلیة التخطیط الحضري واإلقلیمي، جامعة النجاح الوطنیة في نابلس، فلسطین ، كمونة، د. حیدر عبد الرزاق، "التطور الحضاري على مر العصور" مجلة المخطط والتنمیة، .٢٠٠٦)، ١٥العدد( cloke p., "an introduction to rural settlement planning", routledge; 2013 oct 18. mandal r. b., "introduction to rural settlements", 2001. moseley m., "rural development: principles and practice", sage; 2003 apr 21. rosa sa., "sustainable development handbook", the fairmont press, inc.; 2010. ): یوضح إحصائیات حول منطقة الدراسة، المصدر: الباحث.١رقم (جدول عدد البیوت السكنیة عدد األفراد أسم القریة الرمز ٣٠٠ ١٥٠٠ قریة عاید فالح ١ ٦٠ ٥٥٠ قریة عباس عبد زید ٢ ٥٠ ٤٠٠ قریة ھادي عبد زید ٣ ١٢٠ ٥٠٠ قریة فالح عبد الواحد ٤ ٤٠ ٤٠٠ قریة راضي عبد هللا ٥ ): یوضح نتائج التقییم ذو النسبة األعلى حسب اإلستبیان لكل المؤشرات ولكل قریة في منطقة الدراسة، المصدر: ٢جدول رقم ( الباحث. ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١٠ المؤشر الرقم التقییم ذو النسبة األعلى لكل مؤشر ٥قریة رقم ٤قریة رقم ٣قریة رقم ٢قریة رقم ١قریة رقم ال ال الى حد ما ما الى حد الى حد ما مصدر الماء -١ نعم نعم نعم نعم نعم األرض المنتجة -٢ نعم نعم الى حد ما الى حد ما ال كفاءة الموقع -٣ ال ال ال ال ال توفر الخدمات -٤ نعم نعم نعم نعم نعم توفر المواد األولیة -٥ ال ال الى حد ما الى حد ما الى حد ما مستوى الدخل -٦ الى حد ما الى حد ما نعم نعم نعم األنتماء -٧ ال ال الى حد ما الى حد ما نعم األسالیب والتقنیات -٨ الى حد ما الى حد ما نعم نعم نعم التوسع والنمو -٩ نعم نعم نعم نعم نعم مالئمة المناخ -١٠ ): نتائج أعداد و نسب التقییم لكافة المؤشرات لكل قریة في منطقة الدراسة، المصدر: الباحث.٣جدول رقم ( رقم القریة أعداد ونسب التقییم لكافة المؤشرات (ال) (الى حد ما) )نعم( النسبة العدد النسبة العدد النسبة العدد %٢٠ ٢ %٢٠ ٢ %٦٠ ٦ ١ریة ق %١٠ ١ %٤٠ ٤ %٥٠ ٥ ٢قریة %١٠ ١ %٤٠ ٤ %٥٠ ٥ ٣قریة %٤٠ ٤ %٢٠ ٢ %٤٠ ٤ ٤قریة %٤٠ ٤ %٢٠ ٢ %٤٠ ٤ ٥قریة ): نتائج نسب التقییم لكل مؤشر في منطقة الدراسة ولكافة القرى، المصدر: الباحث.٤جدول رقم ( المؤشر الرقم القرى نسب تقییم المؤشرات لكافة ال الى حد ما نعم %٤٠ %٦٠ %٠ مصدر الماء -١ %٠ %٠ %١٠٠ األرض المنتجة -٢ %٢٠ %٤٠ %٤٠ كفاءة الموقع -٣ %١٠٠ %٠ %٠ توفر الخدمات -٤ %٠ %٠ %١٠٠ توفر المواد األولیة -٥ %٤٠ %٦٠ %٠ مستوى الدخل -٦ %٠ %٤٠ %٦٠ األنتماء -٧ %٤٠ %٤٠ %٢٠ األسالیب والتقنیات -٨ والنموالتوسع -٩ ٠ %٤٠ %٦٠% ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١١ %٠ %٠ %١٠٠ مالئمة المناخ -١٠ %٢٤ %٢٨ %٤٨ معدل نسب التقییم ): خارطة منطقة الدراسة، المصدر: الباحث.١شكل رقم ( ): معدل نسب التقییم الكلیة للمؤشرات ولكافة القرى الریفیة في منطقة الدراسة، المصدر: الباحث.٢شكل رقم ( ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١٢ مقترح لمخطط المنطقة الریفیة، المصدر: الباحث.):نموذج ٣شكل رقم ( ):نموذج مقترح لمخطط الوحدة السكنیة، المصدر: الباحث.٤شكل رقم ( )١ملحق رقم ( نموذج أستمارة إستبیان ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١٣ الریفي في تحقیق التنمیة الریفیة المستدامة االستقرارأسم البحث: دور معاییر لغرض البحث العلمي فقط، یرجى الدقة في اإلجابة مع التقدیر.مالحظة: المعلومات المطلوبة تستخدم أخي المواطن أجب بعالمة (صح) أمام التقییم المناسب لك. أستمارة اإلستبیان القسم األول: المعلومات العامة عن القریة عدد البیوت السكنیة: -٣ عدد األفراد: -٢ أسم القریة:-١ القسم الثاني: أسئلة االستمارة السؤال المؤشر ت التقییم نعم الى حد ما ال ١. مصدر الماء ھل ان كمیة المصدر المائي المتوفر في قریتك یكفي لسد أحتیاجاتك لري األراضي الزراعیة؟ ھل أن األرض الزراعیة التي تملكھا صالحة للزراعة؟ األرض المنتجة .٢ ٣. كفاءة الموقع من مشاكل الجفاف و التلوث ھل أن األرض الزراعیة خالیة بالطمر الصحي او غیرھا؟ ٤. توفر الخدمات ھل یرضیك مستوى الخدمات األساسیة لتسییر الحیاة الیومیة في قریتك؟ ٥. توفر المواد األولیة ھل تتوفر المواد األولیة الالزمة لألستعماالت الیومیة في قریتك؟ للعمل وكسب الرزق؟ھل تتوفر في قریتك فرص مستوى الدخل .٦ ھل تفضل العیش واإلستقرار داخل قریتك؟ االنتماء .٧ ھل أن اآللیات الزراعیة الموجودة تكفي إلنجاز العمل؟ األسالیب والتقنیات .٨ ھل ترغب في أن تتوسع قریتك في المستقبل؟ التوسع والنمو .٩ والزراعة؟ ھل أن المناخ مالئم في المنطقة للسكن مالئمة المناخ .١٠ )٢ملحق رقم ( تقییم المؤشرات حسب أستمارة اإلستبیان ولكافة المستقرات الریفیة المؤشر ت )١٥٠) عدد العینات (١تقییم القریة رقم ( ال الى حد ما نعم النسبة العدد النسبة العدد النسبة العدد %٣٣ ٥٠ %٦٠ ٩٠ %٧ ١٠ مصدر الماء .١ %٥ ٧ %٥ ٨ %٩٠ ١٣٥ األرض المنتجة .٢ %٦١ ٩٢ %٢٦ ٣٩ %١٣ ١٩ كفاءة الموقع .٣ %٩١ ١٣٦ %٥ ٨ %٤ ٦ توفر الخدمات .٤ %٦ ٩ %٩ ١٣ %٨٥ ١٢٨ توفر المواد األولیة .٥ %٧ ١١ %٨١ ١٢١ %١٢ ١٨ مستوى الدخل .٦ %٣ ٤ %٤ ٦ %٩٣ ١٤٠ االنتماء .٧ %٤ ٦ %٨ ١٢ %٨٨ ١٣٢ األسالیب والتقنیات .٨ %٩ ١٤ %١١ ١٧ %٧٩ ١١٩ التوسع والنمو .٩ %٥ ٧ %١٣ ٢٠ %٨٢ ١٢٣ مالئمة المناخ .١٠ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١٤ المؤشر ت )٥٥) عدد العینات (٢تقییم القریة رقم ( ال الى حد ما نعم النسبة العدد النسبة العدد النسبة العدد %٢٢ ١٢ %٦٩ ٣٨ %٩ ٥ مصدر الماء .١ %٩ ٥ %١٥ ٨ %٧٦ ٤٢ األرض المنتجة .٢ %٢٠ ١١ %٦٥ ٣٦ %١٥ ٨ كفاءة الموقع .٣ %٨٤ ٤٦ %١١ ٦ %٧ ٤ توفر الخدمات .٤ %١٥ ٨ %١٦ ٩ %٦٩ ٣٨ توفر المواد األولیة .٥ %٩ ٥ %٧٣ ٤٠ %١٨ ١٠ مستوى الدخل .٦ %٤ ٢ %٧ ٤ %٨٩ ٤٩ االنتماء .٧ %١١ ٦ %٧٥ ٤١ %١٥ ٨ األسالیب والتقنیات .٨ %١٥ ٨ %٢٠ ١١ %٦٥ ٣٦ التوسع والنمو .٩ %٩ ٥ %٢٤ ١٣ %٦٧ ٣٧ مالئمة المناخ .١٠ المؤشر ت )٤٠) عدد العینات (٣تقییم القریة رقم ( ال الى حد ما نعم النسبة العدد النسبة العدد النسبة العدد %٢٥ ١٠ %٥٥ ٢٢ %٢٠ ٨ مصدر الماء .١ %٥ ٢ %٢٠ ٨ %٧٥ ٣٠ األرض المنتجة .٢ %٢٥ ١٠ %٦٠ ٢٤ %١٥ ٦ كفاءة الموقع .٣ %٧٥ ٣٠ %١٠ ٤ %١٥ ٦ توفر الخدمات .٤ %١٠ ٤ %١٠ ٤ %٨٠ ٣٢ األولیة توفر المواد .٥ %٢٠ ٨ %٧٠ ٢٨ %١٠ ٤ مستوى الدخل .٦ %١٠ ٤ %١٠ ٤ %٨٠ ٣٢ االنتماء .٧ %١٥ ٦ %٦٠ ٢٤ %٢٥ ١٠ األسالیب والتقنیات .٨ %٢٠ ٨ %٢٥ ١٠ %٥٥ ٢٢ التوسع والنمو .٩ %٥ ٢ %١٥ ٦ %٨٠ ٣٢ مالئمة المناخ .١٠ المؤشر ت )٥٠) عدد العینات (٤تقییم القریة رقم ( ال الى حد ما نعم النسبة العدد النسبة العدد النسبة العدد %٦٠ ٣٠ %٢٤ ١٢ %١٦ ٨ مصدر الماء .١ %١٢ ٦ %١٦ ٨ %٧٦ ٣٨ األرض المنتجة .٢ %١٤ ٧ %٢٤ ١٢ %٦٢ ٣١ كفاءة الموقع .٣ %٨٠ ٤٠ %١٢ ٦ %٨ ٤ توفر الخدمات .٤ %١٠ ٥ %١٤ ٧ %٧٦ ٣٨ توفر المواد األولیة .٥ %٦٦ ٣٣ %٢٠ ١٠ %١٤ ٧ مستوى الدخل .٦ %١٠ ٥ %٦٨ ٣٤ %٢٢ ١١ االنتماء .٧ %٧٠ ٣٥ %٢٠ ١٠ %١٠ ٥ األسالیب والتقنیات .٨ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ١٥ %١٦ ٨ %٥٨ ٢٩ %٢٦ ١٣ التوسع والنمو .٩ %١٠ ٥ %١٢ ٦ %٧٨ ٣٩ مالئمة المناخ .١٠ المؤشر ت )٤٠) عدد العینات (٥تقییم القریة رقم ( ال الى حد ما نعم النسبة العدد النسبة العدد النسبة العدد %١٠ ٤ مصدر الماء .١ ١٥ ٦% 30 %75 5% 2 15% 6 80% 32 األرض المنتجة .٢ %٨٥ ٣٤ كفاءة الموقع .٣ ١٠ ٤% ٥ ٢% 75% 30 15% 6 10% 4 توفر الخدمات .٤ 5% 2 20% 8 75% 30 توفر المواد األولیة .٥ 75% 30 10% 4 15% 6 مستوى الدخل .٦ 15% 6 60% 24 25% 10 االنتماء .٧ 80% 32 15% 6 5% 2 األسالیب والتقنیات .٨ 15% 6 60% 24 25% 10 التوسع والنمو .٩ 10% 4 10% 4 80% 32 مالئمة المناخ .١٠ 12-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 computer modeling of smart antenna system muhammed salah sadiq asst. lec. department of technical electrical power technical college /al-musayab abstract this research studied the adaptive smart antenna system using in cellular phone applications using matlab simulation. in this work, the proposed novel least mean square algorithm (no-lms) build and studied the results as comparative work with results of two another algorithms called standard lms algorithm (s-lms), and normalized lms algorithm (n-lms). the computer simulation work results based no-lms algorithm have better performance refer to obtain the optimum convergence factor (cf) and shows that robustness smart system, good tracking capability, and high adaptation accuracy than the other algorithms. the smart antenna system that is based on lms-algorithms for all types (s-lms),(n-lms),and (no-lms) show that this system is affected by the convergence factor, the computer simulation results shows the minimum mean square error (mse = 0.007) is obtained for the value of convergence factor equal to (0.2). also the smart system is affected by the number of the antennas are used in smart array and number of samples interval, at least three antennas gives the poor steering of array with large mse value (0.15). the test of the three algorithms for different values of signal to noise ratio (snr) show that the (no-lms) algorithm gives the minimum mse values compared with the two those obtain from other algorithms. keywords: smart antenna system, computer modeling, noise ratio. محمد صالح صادق مدرس مساعد / الخالصة .)no-lms ()s-lms ()n-lms ( )no-lms ()cf ( )no-lms ( .)lms ( )0.2=cf ( )mse = 0.007 ( . ، )٠.١٥.( al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 )no-lms ( . 1. introduction a smart antenna system combines multiple antenna elements with a signal processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment (trees2002). over the last few years the demand for wireless services has risen dramatically. this fact introduces a major technological challenge to the design engineer: that is to increase the overall performance and efficiency of the wireless system with an increased number of users under the constraints of spectrum efficiency, power usage and cost. most of the research on this topic, until very recently, has been largely focused on the development of modulation and coding techniques as well as communication protocols, very little attention has been paid to the overall transceiver structure and antenna technology. recently developed smart antenna technology may be the solution to satisfying the requirements of next generation wireless networks (chris, et.al, 2003). smart antenna for mobile communication has received enormous interests worldwide in recent years. in the last decade, wireless cellular communication has experienced rapid growth in the demand for provision of new wireless multimedia services such as internet access, multimedia data transfer and video conferencing. smart antennas involve processing of signal induced on an array of antennas. they have application in the areas of radar, sonar, medical imaging location based application and cellular phone applications (shaukat 2009). this paper represents the study of performance and design of adaptive smart antenna algorithm used in cellular phone applications. this algorithm is studied for different levels of intelligence. the performance of novel least mean square (no-lms) algorithm with standard-lms algorithm and normalized lms (n-lms) algorithm has been compared. smart antennas shown in figure (1) refer to a group of antenna technologies that increase the system capacity by reducing the co-channel interference and increase the quality by reducing the fading effects (trees, 2002). a smart antenna array containing m identical elements can steer a directional beam to maximize the signal from desired users, signals of interest (soi), while nullifying the signals from other directions, signals not of interest (snoi) (chris2003). there are many adaptive algorithms that can be used to adjust the weight vector, the beam former must be implemented subject to a number of contradictory demands, regarding to the best choice of the algorithm. the analog-to-digital converters (adcs) in such systems will be located as close to the antennas as possible in order to achieve almost complete digital processing. in order to realize this, adcs capable of digitizing a high-frequency wideband signal at very high sampling rates will be required along with wideband or multi-band antennas and rf analog devices. however, direct analog-todigital conversion at over sampling rates of very high rf or if signals, typically ranging between hundreds of mhz to several ghz, may not yet be practical because the reasonably price adcs and sufficiently high-speed digital devices, such as current signal processors and buffer memories, cannot be used. the under sampling technique is always useful by performing frequency down conversions and quantization at the same time (minseok, 2004). the most appropriate criterions include:(1) computational complexity, defined as the number of snapshots required to converge to the optimum solution, (2) robustness, which is an ability of the algorithm to behave satisfactorily under finite word precision numerical operation, and (3) implementation issue. one important class of beamforming algorithms are the non blind algorithms in which training signal is used to adjust the array weight vector (shaukat, 2009). al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 2types of smart antennas (rappaport 98) there are basically two approaches to implement antennas that dynamically change their pattern to mitigate interference and multi path affects while increasing coverage and range. they are:switched beam adaptive arrays the switched beam approach is simpler compared to the fully adaptive approach. it provides a considerable increase in network capacity when compared to traditional omni directional antenna systems or sector-based systems. in this approach, an antenna array generates overlapping beams that cover the surrounding area as shown in figure (2a). when an incoming signal is detected, the base station determines the beam that is best aligned in the signal-of-interest direction and then switches to that beam to communicate with the user. the continuously by steering the main beam towards the user and at the same time forming nulls in the directions of the interfering signal as shown in figure (2b). like switched beam systems, they also incorporate arrays. typically, the received signal from each of the spatially distributed antenna elements is multiplied by a weight. the weights are complex in nature and adjust the amplitude and phase. these signals are combined to yield the array output. these complex weights are computed by a complicated adaptive algorithm, which is pre-programmed into the digital signal-processing unit that manages the signal radiated by the base station. 3. benefits of smart antenna technology (ahmed2005):smart antennas have several advantages over other antenna systems. for example, smart antennas are able to increase the data transfer rate of a wireless signal as well as reduce the number of errors or obstructed pieces of data. smart antennas are also able to calculate the direction of arrival of a wireless signal and effectively alert the user to where the signal is the strongest. smart antennas are easy to use and depend on plug-and-play technology. many advantages that realize by smart system are:3.1 reduction in co-channel interference smart antennas have a property of spatial filtering to focus radiated energy in the form of narrow beams only in the direction of the desired mobile user and no other direction. 3.2 range improvement since smart antennas employs collection of individual elements in the form of an array they give rise to narrow beam with increased gain when compared to conventional antennas using the same power. the increase in gain leads to increase in range and the coverage of the system. therefore fewer base stations are required to cover a given area. 3.3 increases in capacity smart antennas allow more users to use the same frequency spectrum at the same time bringing about tremendous increase in capacity. 3.4 mitigation of multi path effects smart antennas can either reject multi path components as interference, thus mitigating its effects in terms of fading or it can use the multi path components and add them constructively to enhance system performance. 3.5 compatibility smart antenna technology can be applied to various multiple access techniques such as tdma, fdma, and cdma. it is compatible with almost any modulation method and bandwidth or frequency band. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 3.6 signal gain inputs from multiple antennas are combined to optimize available power required to establish given level of coverage. 4. the lms and n-lms algorithms:4.1 lms-algorithm (hykin 96) the algorithm uses a gradient descent to estimate a time varying signal. the gradient descent method finds a minimum, if it exists, by taking steps in the direction negative of the gradient. it does so by adjusting the filter coefficients so as to minimize the error. the gradient is the del operator (partial derivative) and is applied to find the divergence of a function, which is the error with respect to the nth coefficient in this case. the lms algorithm approaches the minimum of a function to minimize error by taking the negative gradient of the function. lms algorithm can be implemented as shown in figure (3) the desired signal d (n) is tracked by adjusting the filter coefficients c (n). the input reference signal x (n) is a known signal that is fed to the fir filter. the difference between d (n) and y (n) is the error e (n). the error e (n) is then fed to the lms algorithm to compute the filter coefficients c (n+1) to iteratively minimize the error. 4.2 n-lms-algorithm (rallapall2007) most parameters of the nlms algorithm are the same as the lms algorithm, except that the step size or the coverage factor is now bounded between 0 and 2. the normalization term, makes the convergence rate independent of signal power. the normalized least mean square algorithm (n-lms) is an extension of the lms algorithm, which bypasses the step size issue by selecting a for each iteration of the algorithm. this step size is proportional to the inverse of the total expected energy of the instantaneous values of the input vector. the n-lms algorithm shows far greater stability with unknown signals. this combined with good convergence speed and relative computational simplicity makes the nlms algorithm ideal for the real time adaptive echo cancellation system. as the nlms is an extension of the standard lms algorithm, the n-lms algorithms practical implementation is very similar to that of the lms algorithm. 5. adaptive smart antenna model (asa-model) figure (4) demonstrates the adaptive smart antenna model; the asa-model is proposed and discussed as comparative work between (no-lms) algorithm with s-lms algorithm and (n-lms) algorithms by use the matlab simulation program. the system model shown can be used to test the different algorithms performance and scope the novel and optimal one in different environments. where:u (r) : represents the input signal from uniform linear array. m (r) : the output signal from the unknown channel. i (r): the interference signal. y (r): the received signal is obtained by summing the interference signal with m (r). the signal y (r) is applied to the adaptive equalizer to reduce the noise that is generated by the effect of the channel. the output of the equalizer gives the signal x (r). this signal is compared with the original transmitted signal u (r) to obtain the error signal e (r). let the unknown channel is represented mathematically as a function (1/jc), and the adaptive equalizer as (e). in the case of absence the interference effect (ideal channel), that mean the output of equalizer x (r) is the same input signal u(r) and we can obtain (shannon8):jc = e (1) that produces al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 1 cj e (2) from figure(4) the unknown channel is assumed the linear channel with response same as the response of the finite impulse response filter with time (t):adaptive ]..,.........,,[ 1210 cncccc jjjjj (3) the parameters of the equalizer can written as:],,.........,,[)( 1210 neeeere (4) for the nth lms-filter parameters:1.......,.........3,2,1,0,0)0( nforiei the output of unknown channel:)]1(...,),........3(),2(),1([)( nrmrmrmrmrm (5) the output is calculated as: (6) by adding the interference signal the received signal become and can show in figure (5):)()()( rirmry (7) )]1(..,),........2(),1(),([)( nryryryryry (8) the equation (8) represents the received signal in matrix form, and the output of the equalizer is:)()1()( ryrerx t (9) the resultant error signal:)()()( rxrure (10) if the error signal is equal to the interference signal that refer to the adaptive smart antenna system based the lms-algorithms is estimated the unknown channel successfully and the standard lms-algorithm can represented:)().()1()( reryrere (11) where (μ) is the convergence factor (cowan85). 6. computer simulation test:6.1 choice of convergence factor the convergence factor (μ) controls how far we move along the error function surface at each update step. convergence factor certainly has to be chosen > 0 (otherwise we would move the coefficient vector in a direction towards larger squared error). also this parameter must not become too large. furthermore, too large a convergence factor causes the lms algorithm to be instable, i.e., the coefficients do not converge to fixed values but oscillate. closer analysis (hykin96) reveals, that the eigen value )():2()(( )1( 1 )( rmnjru j rm tc c al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 max) of the tap-input auto-correlation matrix and thus on the input signal. for stable adaptation behavior the coverage factor has to be:max 2 0 (12) the convergence time of the lms algorithm depends on the convergence factor (μ). if μ is small, then it may take a long convergence time and this may defeat the purpose of using an lms filter. however if μ is too large, the algorithm may never converge (amrita2010). 6.2 novel algorithm there is proportion between the stability of the adaptive algorithm and the convergence ratio for the smart system if the μ-value is large that produces the fast convergence ratio but this fast convergence ratio led to low stability and low accuracy for smart system. in other hand, the low values give good stability the accuracy. the no-lms algorithm is suggested to give the suitable convergence factor, this factor is dependent upon the equation:. ]))([(.2 ]))([( 0 2 2 ree rue (13) where:(u(r))2: input signal power. (e(r))2: error signal power. e[ ]: the expected value. figure (7) snr a 1.0102 (14) equation (14) graph can be shown in figure (6) where:a: the input signal amplitude. snr: the signal to noise ratio. now the error signal equation can be written: )().()( rurwre h (15) where wh(r) the estimated of the tap weight of lms-filter. 7. results and discussion the computer simulation test using matlab simulation program for asa-model based three algorithms called s-lms, n-lms, and no-lms show that:from the figure (7) the no-lms algorithm has the optimum performance compared with the other two algorithms (s-lms, and n-lms) for small values of the mean square error (mse) and the sample interval, whereas the two other algorithms need the large values of mean square error (mse) and the sample interval at the same value of convergence factor (cf =0.2) to be stable. by varying the value of the convergence factor from the value 0.04 and below, the mse values is increased and that produces unstable system as shown in figure (8), but from this values the nolms algorithm gives the good system stability but for the large numbers of sample interval, the n-lms algorithm produces low stability for large number of sample interval, and the s-lms algorithm fail. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 the relationship between the mean square error and the number of the convergence factor for increase the values of cf from 0.26 and above, the system tends to be unstable that can be shown in figure (9). figure (10) represents the inverse proportion between the number of antennas and the mse values when the number of antennas is increased that led to reduce the value of the mse and vice versa; that means the asa system is affected by the number of the antennas in the array. the other test that appears the good performance of (no-lms) algorithm over the other two algorithms can be shown in figure (11), when varying the values of snr the (no-lms) algorithm still gives conceivable errors than that obtained from the other algorithms (s-lms, and n-lms). 8. conclusions the optimum convergence factor for the minimum mean square error is obtained to no-lms algorithm whereas s-lms and n-lms algorithms gives mean square error values larger than that obtain from no-lms for same value of convergence factor; that means this algorithm (no-lms) gives best performance also in bad conditions. the smart system used in cellular phone applications is affected by the fine varying for convergence factor, and the stability of the whole system depends on these fine variations of different types of algorithms, these variations of same as slow tuning for small steps, also this small value variations of convergence factor appear the considered effect on system performance. the computer simulation test shows that number of antenna in smart array also has large effect on the stability of the system based to this array. the s-lms gives bad performance and fails in worst environments. 9. references 1. ahmed el zooghby "smart antenna engineering", artech house, second edition, p-7, 2005. 2. amrita rai, amit kumar "analysis and simulation of adaptive filter with lms algorithm", international journal of electronic engineering", vol (2), pp121-123, 2010. 3. c.f.c cowan, p.m. grant " , prentice hall, 1985. 4. chris loadman, zhizhang chen, and dylan jorgen "an overview of adaptive antenna technologies for wireless communications" , communication networks and series research conference, session a3, moneton, new brunswick canada, 2003. 5. hykin, simon " , third edition, prentice hall inc.nj, 1996. 6. ,phd. thesis, 2004. 7. n.p. rallapall, s. sharma, and -et, sept, 2007. 8. rappaportm t. s. " smart antennas: adaptive array algorithms and wireless position , new york, ieee press, 1998. 9. s.f.shaukat, mukhtar ul hassan, and r. farooq "sequential studies of beam forming -6, pp 754-758, 2009. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10. shannon liew " , phd.thesis, 2002,university of queensland. 11. trees h.v. "detection, estimation, , partiv, optimum array processing, john wiely&sons, 2002. figure (1) smart antenna block diagram figure (2a) switched beam system figure (2b) adaptive array system al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (3) the lms-algorithm figure (4) the asa-model al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 100 200 300 400 500 600 700 800 900 1000 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 y(r) signal figure (5) the received signal y (r) figure (6) the standard deviation 0 1 2 3 4 5 6 7 8 9 1 0 0 0 . 1 0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 0 . 8 0 . 9 1 t im e g a u s s ia n al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 500 1000 1500 2000 2500 3000 3500 4000 -35 -30 -25 -20 -15 -10 -5 0 sample interval m ea n sq ua re e rr or s-lms no-lms n-lms no-lms n-lms s-lms figure (8) mse versus the sample interval for cf ≤0.04 0 500 1000 1500 2000 2500 3000 3500 4000 -35 -30 -25 -20 -15 -10 -5 0 sample interval m ea n sq ua re e rro r s-lms n-lms no-lmss-lms no-lms n-lms figure (7) mse versus the sample interval for cf = 0.2 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 0 5 10 15 20 25 30 35 40 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 no. of antenna m s e figure (10) mse versus the number of antennas figure (9) mse versus the convergence factor al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 2 3 4 5 6 7 8 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 snr db m s e s-lms n-lms no-lms figure (11) error versus the signal to noise ratio temperature effect on dispersion in single-mode optical fibers for different materials al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨١ dispersion in different single mode optical fiber materials at different temperatures aqeel salim raheem technical college – najaf abstract optical fiber is a physical medium for optical communication system. it is offer high capacity, very wide band and high data rate. there are two main problems in this physical medium that are dispersion and power loss. the significant restriction in optical fiber system is the dispersion. the dispersion affects the performance of the system and bit error rate. there are two types of dispersion intermodal and intramodal. intermodal occurs in multimode fiber only. intramodal occur in all type of fiber. the total dispersion in single mode fiber is the sum of material and waveguide dispersion. in this paper the effect of temperature variations on fiber dispersion is investigated. the temperature variant is a vital factor which plays an effective role on activity of the communication system especially in environmental of iraq and other middle east country. the sellemeier coefficients equation is derived for fixed and discrete temperature values. a derivation for this equation to fit continues variation of temperature is done in this paper for optical fiber. depend on formula of dispersion, sellemeier coefficients equation and relation of refractive index at any temperature derivation of propagation constant with normalized frequency for waveguide dispersion is done. the temperature effect on total dispersion is modeled for most popular material used in fabrication optical fiber, silica (sio2), aluminosilicate (al2sio5) and vycor glass (96.4%sio2 ,3% b2o3, 0.5%al2o3, 0.1% miscellaneous traces). both single mode step index and graded index fibers are considered. the results investigated by using matlab and maple programs. the refractive index temperature dependence for all three fiber types are fitted in to straight line. the material dispersion and zero material dispersion "λo" wavelengths have approximately linear temperature dependence for all three fiber types. for wide range of increasing temperature [-100◦c to 100◦c] sio2 and vycor glass fiber has less effect than for aluminosilicate. the temperature variation shows the step index fiber batter than graded index fiber. the sio2 is the best one of three fiber types. عند درجات حرارة مختلفةالبصریة ذات النمط الواحدااللیافموادمختلففيالتشتت عقیل سالم رحیم النجف/ الكلیة التقنیة :الخالصة لتطور لمتطلبات انتیجةمع زیادة معدل نقل البیاناتو التي ،لالتصاالتالمستخدمةالمادیةاالوساطھي واحدة من الضوئیةأللیاف ا لقد تم أختیارو.ھذا العمل فيبعین االعتباراخذ و الذيشتت ،التشارة بسبب االتدھورتعاني من ،الحاصل في مجال االتصاالت http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٢ وما ، والضوئیةاأللیافعلىدراسة تأثیر تغیرات درجة الحرارة لموجي التشتت الماديعالقةالرئیسیة للتشتت واشتقاقعلى أساس الصیغةحیث ان حساباتنا اعتمدت، اللیف الضوئي ول ا الط مع .لدلیل الموجيلتشتت اتطبیعالار مع تردد كسنالاثابت عالقة واشتقاق دد ھذه المتغیرات عند اان القیم االساسیة لمتغیرات معامل االنكسار وعالقة ایج لكلي تشتتال.المعتمد في الدراسة موجودة في الملحق لماد شتتت الا درجة ختار تم ا .ويا درجات ان ر من بلدیكثوالبلدنایف الضوئي وذلك لئنلكعامل مؤثر على انتقال االشارة خالل ال الحرارة غرار وعلىاأللیاف الضوئیة كوسیلة المادیةخدامتاسباالتصاالتعالیة لفترة طویلة من السنة ، مما یعطي عامال ھاما في الحرارة استخدم افیھوالتحقیق ) المادي والدلیل الموجي(تأثیر درجة الحرارة على تشتت لزجاج ) 5sio2al(، ألومینوسیلیكات) 2sio(السلیكامثل ، مجة ا نتائج ال.vycorوا بر استخدام من ال ب مواد نا.المابلماتالب والبرامج البرنامج تقظھر"oλ"الطول الموجي الصفريتشتت المادي وال،خط مستقیمنطبق على شكلا ضوئیة الوصنوعة من األلیاف الظھر أن]مئویة١٠٠الى ١٠٠-[تغیر درجة الحرارةمن لمدى واسعحیث. األلیاف الثالثةأنواع )2sio وvycor (أللومینوسیلیكاتاااللیاف المصنعة منأقل منت بشكل تأثر)5sio2al( .ال ]2sio[أنو.، فضل من اللیف ذو مؤشر المتدرجاللیف ذو مؤشر الخطوة أدرجة الحرارة .ثالثةالمن أنواع األلیاف keywords temperature effect on dispersion, total dispersion, zero dispersion wavelengths, chromatic dispersion, optical fiber, sellmeier coefficients, intermodal dispersion, interamodal dispersion, sellemeier coefficients, refractive index. introducion optical fiber is more preferred medium for high capacity communication systems.[ michael 2002] due to the fast grow up of communication system. due to low insertion loss, high flexibility in spectral design and high data rate transmission many intensive studies done for applications in optical communications. dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or when the group velocity depends on the frequency. dispersion of the transmitted optical signal causes distortion (broadening) of transmitted signal (pulses) along optical fibers. there are two types of dispersion intermodal and interamodal. the intermodal dispersion results from the propagation delay differences between modes within a multimode optical fiber. intramodal or chromatic dispersion occur in all fiber types and results from the finite spectral line width of the optical source. chromatic dispersion it is wavelength-dependent nature. single mode fiber has only intramodal mechanisms. the propagation delay differences between the different spectral components of the transmitted signal may be caused by:  the dispersive properties of the fiber material (material dispersion; dm)  the guidance effects within the fiber structure (waveguide dispersion dw). .[rostami 2007][ jeong2009][ michael2002] generally two sources of intramodal (or chromatic) dispersion: material dispersion and waveguide dispersion.  material dispersion comes from a frequency dependent on waveguide material. waveguide dispersion comes from a frequency dependent on waveguide geometric. it is independent on materials from which it is constructed. .[rostami 2007][ jeong2009][ tzong1995] in 1982, most applications started converting from multimode to step index single-mode fibers operating at 1300 nm. today, a few applications are being planned for use with multimode fibers and the systems operating wavelength has to move to 1550 nm. [debell1989] much research deal with dispersion, experimentally measured the refractive index and dependent on temperature for calcium telluride by using liquid helium as a coolant. [debell1989] al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٣ modeled the chromatic dispersion in single mode fiber by using material dielectric function for material dispersion and dependence of both propagation constant and normalized frequency on wavelength. [moustafa1991] proposed a novel numerical approach for calculation of dispersion coefficients of dual mode elliptical core fiber with arbitrary refractive index profile. [kato2000] measured refractive indices of several fused silica and calcium fluoride. [gupta1998] experimentally study the change of chromatic dispersion of optical fiber with temperature by demonstrated the empirical model of last reaches. [hamp2002]. investigates imperially the impact of dispersion and dispersion slop on transmission performance including the effect of temperature variation of fiber optic.[vorbeck 2003] determine numerically the dispersion in optical fiber modeled investigated by vorbeck.[chich-chenge chou 2003] derive chromatic dispersion slop variation with temperature as a function of zero dispersion wavelength and chromatic dispersion slop at zero dispersion wavelength.[andre 2004] experimentally demonstrated a novel chromatic dispersion monitoring techniques using frequency modulated and amplitude modulated pilot tones.[pual2006] use analytical method to compensated the chromatic dispersion in optical fiber by management of optimum group velocity dispersion.[rostami 2007] presents a modification of interferometric method for measurement of optical fiber chromatic dispersion using michelson interferometer.[peterka 2008] modeled a new method to control free spectral range of long period fiber grating.[jeong2009] experimentally measure the temperature and pressure verses wavelength in different elliptical core fiber.[urbanczyk 2010] mathematical model in the following, the equations of sellmeier coefficients for the core refractive index are described for three kinds of fiber glasses: sio2, aluminosilicate (al2sio5), and vycor glasses. the temperature dependence of these coefficients is determined. material and waveguide dispersion parameters are studied leading to the zero dispersion wavelengths, λo, of the total dispersion parameter. the temperature effect on λo is investigated. the result obtained for λo under different temperature environments.  sellemeier coefficients the core refractive index, n, as a function of the operating wavelength, λ, is defined through the sellmeier equation which has the form: [.li1989], [paul 2006][ gupta1989] e d c b an     2 2 2 2 2     (1) where: a, b, c, d and e: are sellmeier coefficients  : is the wavelength of optical signal (nm) n: is the refractive index of optical fiber core the first and second terms represent, respectively, the contribution to refractive index due to higher energy and lower energy gaps of electronic absorption, while the last term accounts for the decrease in refractive index due to lattice absorption. the values of the sellmeier coefficients are listed (table (1)) in appendix and the relation of finding these coefficients at any temperature are given by: .[ matsuoka1989] )()( dt dn rtnn rt  (2) where: http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٤ t: is the temperature in degree centigrade, r: is the room temperature, nt and nr are the refractive indexes at t and room temperature, respectively  material dispersion total dispersion of a fiber is conventionally expressed as temporal broadening per unit length of the fiber, per unit width of the light source used. this total dispersion caused by material and structural properties of the fiber is in fact totally coupled. however, the total dispersion parameter, dt, is expressed as[ chou2003][ jeong2009][ . bass 2002] dt = md + wd (3) where: md: material dispersion (ps / nm.km) wd: waveguide dispersion (ps / nm.km) material dispersion manifests through the wavelength dependence of the refractive index, n(λ), by the following relation: [ chou2003][ jeong2009][ hamp 2002][ paul and park2006] 2 2 *)(    d nd c m d  (4) where: dm : is the material dispersion (ps / nm.km)  : is the wavelength of optical signal (nm) c: is the free space speed of light.  waveguide dispersion the waveguide dispersion in optical fibers is given by: [jeong2009][hamp 2002][paul and park2006] 2 22 2 dv d c v w d    (5) where: wd: waveguide dispersion (ps / nm.km) v: is the normalized frequency β: is the propagation constant. c: is the free space speed of light. now the normalized frequency “v “given by: [12] 2 1 22 )(.. 2 bn nnav    (6) where: nn: core refractive index, nb: cladding refractive index, al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٥ a: is the core radius (µ m)  : is the wavelength of optical signal (nm) for step-index fibers, the propagation constant, β, is given by: [ .rostami2007][ paul and park2006] 5.0 2 2 2 2 2          aa v   (7) where: β:is the propagation constant a: is the core radius (µ m), δ: is the relative refractive index difference between core and cladding δ= nn nb v: is the normalized frequency while, for graded-index fibers, β is given by: [rostami2007][paul and park2006] 5.0 22 2 6 2          a v a v  (8) results and discussion the temperature dependent of refractive index (using equation (1)) simulated for the sio2, aluminosilicate (al2sio5), and vycor glasses which are used in fabrication of optical fiber, the results shown in figure (1). the refractive indices are calculated at 850nm wavelength and at temperature ranged from 20 oc to 100 oc , the sellmeier coefficients that used in simulation listed in appendix and relation of founding sellmeier coefficients at any temperature written in appendix. the refractive index results are found to fit nicely into straight lines for the three material simulated. material dispersion is calculated for the three optical fiber glass types (sio2, aluminosilicate (al2sio5), and vycor glasses) at 26 ◦c using the temperature dependence of sellmeier coefficients, as shown in figure (2). the zero material dispersion wavelengths are 1.2734, 1.3929 and 1.2682 μm for sio2, aluminosilicate (al2sio5) and vycor glass, respectively, and the dispersion characteristics are approximately linear for the whole spectral region. for a wide range of temperature (-100◦c to 100◦c), the material dispersion and the zero material dispersion wavelength, λo, has been calculated for the three optical fiber glass types. the obtained results are shown in figure (3), figure (5) and figure (6) for the sio2, aluminosilicate and vycor glass, respectively. the material dispersion linearly related to temperature, and increases with increase the wavelength for all three tested optical fiber material. the zero material dispersion wavelength (λo) as a function of temperature (t ◦c) is displayed in figure (4) for sio2. interestingly, the temperature dependence is linear and dλo/dt=0.0242 nm/oc for sio2. this value has a fair agreement with the published experimental values 0.029±0.004 nm/oc and 0.031± 0.004nm/oc for two dispersion shifted fibers within the experimental accuracy. the values of dλo/dt are found to be 0.0223 nm/oc for vycor glasses. while the corresponding values of dλo/dt are found to be 0.03 nm/oc for aluminosilicate (al2sio5). using the temperature dependent sellmeier coefficients and the corresponding values of the vnumber, waveguide dispersion and total dispersion for single mode step index fiber calculated at http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٦ a core radius, a = 2 μm , relative refractive index difference between core and cladding ∆ = 0.005, and temperature 26 oc. the waveguide dispersion results of optical fiber (sio2 material) are shown in figure (7) and material, waveguide and total dispersion shown in figure (8). the waveguide dispersion results of optical fiber (aluminosilicate (al2sio5)) are shown in figure (9) and material, waveguide and total dispersion shown in figure (10). the waveguide dispersion results of optical fiber (vycor glass) are shown in figure (11) and material, waveguide and total dispersion shown in figure (12). the waveguide dispersion results have line curved and shift of total dispersion from material dispersion. for sio2 fiber material dispersion has (λo = 1.2723 µ m) and total dispersion has (λo = 1.28 µ m), aluminosilicate fiber, material dispersion has (λo = 1.3925 µ m) and total dispersion (λo = 1.397 µ m), vycor glass fiber, material dispersion has (λo =1.2675 µ m) and total dispersion has (λo = 1.275 µ m). the waveguide dispersion results has line curved and slight shift of total dispersion from material dispersion, since the value of waveguide dispersion be smaller than the material dispersion the aluminosilicate (al2sio5) fiber give little different results from that given by sio2 fiber and vycor glass fiber. waveguide dispersion and total dispersion for single mode graded index fiber calculated at a core radius, a = 2 μm, relative refractive index difference between core and cladding ∆ = 0.0085, and temperature 26 oc. the waveguide dispersion results of optical fiber (sio2 material) are shown in figure (13) and material, waveguide and total dispersion shown in figure (14). the waveguide dispersion results of optical fiber (aluminosilicate (al2sio5)) are shown in figure (15) and material, waveguide and total dispersion shown in figure (16). the waveguide dispersion results of optical fiber (vycor glass) are shown in figure (17) and material, waveguide and total dispersion shown in figure (18). the waveguide dispersion results have line curved and shift of total dispersion from material dispersion. for sio2 fiber material dispersion has (λo = 1.2723 µ m) and total dispersion has (λo = 1.285 µ m), aluminosilicate fiber, material dispersion has (λo = 1.3925 µ m) and total dispersion (λo = 1.405 µ m), vycor glass fiber, material dispersion has (λo =1.2675 µ m) and total dispersion has (λo = 1.28 µ m) the first and second derivative of refractive index is as follow: 5.0 2 2 2 2 2 3 22 3 )( 2 )( 2 5.0                      e d c b a e d c b d dn          5.0 2 2 2 2 22 2 32 4 22 2 32 4 5.1 2 2 2 2 2 2 3 22 3 2 2 )( 8 )( 8 )( 2 )( 8 5.0 )( 2 )( 2 25.0                                               e d c b a e d e d c b c b e d c b a e d c b d nd                      the first and second derivative of step index propagation constant equation done is as follow: http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٧ the first and second derivative of graded index propagation constant equation is as follow: conclusion: the refractive index temperature dependence for all three fiber types are fitted in to straight line. the material dispersion and zero material dispersion " λo" wavelengths has approximately linear temperature dependence for all three fiber types, sio2 and vycor fibers give nearly similar results while aluminosilicate give little difference one. for wide range of increasing temperature [-100◦c to 100◦c] sio2 and vycor glass fiber has less effect than for aluminosilicate, since the zero material dispersion shifted by 0.01 for sio2 and vycor fiber while 0.025 for aluminosilicate fiber. the linearly shift the total dispersion zero wavelength. for large variation of temperature range step index fiber batter than graded index fiber since for step index "λo" affected by fiber core radius and little affected by the relative refractive index difference between core and cladding " δ" while for graded index fiber "λo" affected by fiber core radius and relative refractive index difference between core and cladding " δ". the sio2 is the best one of three fiber types. the aluminosilicate (al2sio5) fiber give different results from that given by sio2 fiber and vycor glass fiber. 5.0 2 2 2 2 2 5.1 2 2 2 2 22 2 2 2 5.0 2 2 2 2 2 5.0 5.0 5.0 2 5.0 5.0 5.0                         aam v a aam v a v dv d aam v a v dv d     5.0 22 2 2 5.1 22 2 2 22 2 2 5.0 22 2 22 65.0 5.0 65.0 6 25.0 65.0 6 5.0                                             a v a v a a v a v aa v av d a v a v aa v av d   http://en.wikipedia.org/wiki/aluminium http://en.wikipedia.org/wiki/silicon http://en.wikipedia.org/wiki/oxygen al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٨ reference: [1] a.g.debell, e.l.dereniak, j.harvey, j.nissley, j.palmer, a.selvarajan and w.l.wolfe," cryogenic refractive indices and temperature coefficients of cadmium telluride form 6µm to 22µm", applied optics, vol.18, no.18, 15 september 1989. [2] a.rostami," a principle investigation of the group velocity dispersion profile for optimum dispersion compensation in optical fiber", progress in electromagnetics research, pier 75, 209–224, 2007. [3] chich-chenge chou," numerical analysis of dispersion in optical fibers", ieee, vol.1, p.107, 19 dec 2003. [4] h.h.li, "refractive index of zns, znse and znte and its wavelength and temperature derivatives", journal of physics and chemistry reference data, vol.13, no.1, 1989. [5] h.jeong, "theoretical analysis of cladding-mode waveguide dispersion and its effects on the spectra of long-period fiber grating" journal of light wave technology, vol. 21, no. 8, august 2009. [6] j. y. huh, "effect of temperature variation on performance of optical phase conjugation", optical fiber communication conference (ofc) anaheim, california, 6 march 2005. [7] j. matsuoka, n. kitamura, s. fujinaga, t. kitaoka, and h. yamashita, “temperature dependence of refractive index of si02 glass,” journal of non-crystal solution, vol. 135, pp. 86-89, 1991. [8] michael bass, "fiber optics handbook", 2nd edition, mcgraw-hill, 2002. [9] michael j. hamp," investigation into the temperature dependence of chromatic dispersion in optical fiber", ieee photonics technalogy letters, vol. 14, no. 11, november 2002. [10] moustafa h.aly," chromatic dispersion in graded-index single-mode optical fibers", ieee pacific rim conference on communications, computers and signal processing, no.18, may 9-10, 1991. [11] n. shibata, "refractive index dispersion of lightguid glass at high temperature" electronics letters vol.17 no. 8, 16th april 1989. [12] paul k. j. park," a novel chromatic dispersion monitoring technique using frequency-modulated and amplitude-modulated pilot tones", optical fiber communication conference 5-10 may 2006. [13] p. peterka, "measurement of chromatic dispersion of microstructure optical fibers using interferometric method", optica applicata, vol. 38, no. 2, 2008. [14] p. s. andre, "effect of temperature on the single mode fibers chromatic dispersion", journal of microwave and optoelectronics, vol.3, no.5, july 2004. [15] r. gupta, "absolute refractive indices and thermal coefficients of fused silica and calcium fluoride near 193 nm", journal of applied optics vol.37, no.25, 1 september 1998. [16] r. tripathi, "reduction of crosstalk in wavelength division multiplexed fiber optics communication system", progress in electromagnetics research, pier 77, 367–378, 2007. [17] s. p. singh," nonlinear scattering effects in optical fibers", progress electromagnetics research, pier 74, 379–405, 2007. [18] s. vorbeck, "dispersion and dispersion slope tolerance of 160-gb/s systems, considering the temperature dependence of chromatic dispersion", ieee photonics technology letters, vol. 15, no. 10, october 2003. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٨٩ [19] t. kato," temperature dependence of chromatic dispersion in various types of optical fibers", optical fiber communication conference, baltimore, maryland,7 march 2000. [20] u.schlarb, "a generalized sellemeier equation for the refractive indices of lithium niobate", ferroelectronics, vol.156, pp.99-104, 1994. [21] tzong-lin wu," an efficient numerical approach for determining the dispersion characteristics of dual-mode elliptical-core optical fibers", journal of lightwave technology, vol. 13, no. 9, september 1995. [22] w. urbanczyk, "dispersion effects in elliptical-core highly birefringent fibers", journal of applied optics vol. 40, no. 12, pp: 1911–1920, apr. 20, 2001. table (1) sellmeier coefficients material temp. (◦c) a b c d e sio2 20 1.310723 0.7935797 1.0959659*10 -2 0.9237144 100 26 1.3121622 0.7925205 1.0996732*10-2 0.9116877 100 45.2 1.3066410 0.7994875 1.091946*10-2 0.9598566 100 471 1.3148367 0.8034391 1.1248041*10-2 0.9119589 100 alumino-silicate 28 1.4136733 0.8503994 1.3249011*10-2 0.9044591 100 526 1.5205253 0.8556256 1.520523*10-2 0.9092824 100 vycor glass 28 1.2754213 0.8271916 1.0653107*10-2 0.9384236 100 526 1.3488048 0.7695233 1.1884981*10-2 0.946169 100 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٩٠ 20 40 60 80 100 1 2 3 4 5 6 7 temperature r ef ra ct iv e in de x alumino-silicate vycor glass fused silica 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 wavelength d is pe rs io n, p s/ nm .k m material dispersion at 26 c for different material vycor sio2 aluminosilicate figure (1) refractive index for three types of fiber material µm figure (2) material dispersion at 26ºc for different material -100 -50 0 50 100 1.268 1.269 1.27 1.271 1.272 1.273 1.274 1.275 1.276 temperature oc variation of zero material dispersion wavelengths with temperature for sio2 glass. λ◦ λ ◦ figure (3) material dispersion of sio2glasss at different temperature figure (4) variation of zero material dispersion wavelengths with temperature for sio glass µm 1.26 1.265 1.27 1.275 1.28 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 wavelength, µm material dispersion of sio2 glass at different temperatures -100 c -60 c 0 c 60 c 100 c m a te ri a l d is p e rs io n , p s /n m .k m 1.38 1.385 1.39 1.395 1.4 1.405 1.41 1.415 1.42 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 wavelength m at er ia l d is pe rs io n, p s/ nm .k m material dispersion of aluminosilicate glass at different temperatures -100 c -60 c 100 c 0 c 60 c 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.3 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 wavelength m at er ia l d is pe rs io n, p s/ nm .k m material dispersion for vycor glass at diffrent temperature -100 c -60 c 0 c 100 c 60 c figure (5) material dispersion of aluminosilicate glass at different temperature figure (6) material dispersion for vycor glass at different temperature µm µm al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٩١ figure (7) waveguide dispersion for sio2 at t= 26 ºc figure (8) total dispersion parameter for sio2 at t=26 ºc figure (9) waveguide dispersion for aluminosilicate at t=26ºc figure (10) total dispersion parameter for aluminosilicate glass at t=26ºc 1 1.2 1.4 1.6 1.8 2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 wavelength d is pe rs io n, p s/ nm .k m waveguide dispersion for sio2 at t=26 c 1 1.2 1.4 1.6 1.8 2 -1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 wavelength d is pe rs io n, p s/ nm .k m waveguide dispersion for aluminosilicate at t=25 c 1 1.2 1.4 1.6 1.8 2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 wavelength d is pe rs io n, p s/ nm .k m waveguide dispersion for vycor glass at t=26 c 1 1.1 1.2 1.3 1.4 1.5 1.6 -50 -40 -30 -20 -10 0 10 20 30 40 wavelength d is pe rs io n, p s/ nm .k m total dispersion parameter for sio2 at 26 c m t 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 wavelength d is pe rs io n, p s/ nm .k m total dispersion parameter for aluminosilicate glass at t=26 c 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 -50 -40 -30 -20 -10 0 10 20 30 wavelength d is pe rs io n, p s/ nm .k m total dispersion parameter for vycor at 26 c figure (11) waveguide dispersion for vycor glass at t=26ºc figure (12) total dispersion parameter for vycor glass at t=26ºc w t mw t m w µm µm µm µm µm µm al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ٣٩٢ figure (13) waveguide dispersion for sio2 (graded index) figure (14) dispersion behavior for sio2 (graded index) figure (15) waveguide dispersion for aluminosilicate at t=26ºc (graded index) 1 1.1 1.2 1.3 1.4 1.5 1.6 -2.2 -2 -1.8 -1.6 -1.4 -1.2 -1 -0.8 -0.6 wavelength d is pe rs io n, p s/ nm .k m waveguid dispersion for sio2 (graded index) 1 1.1 1.2 1.3 1.4 1.5 1.6 -2.2 -2 -1.8 -1.6 -1.4 -1.2 -1 -0.8 -0.6 wavelength d is pe rs io n, p s/ nm .k m waveguid dispersion for aluminosilicate at 26oc(graded index) 1 1.1 1.2 1.3 1.4 1.5 1.6 -50 -40 -30 -20 -10 0 10 20 30 40 wavelength d is pe rs io n, p s/ nm .k m dispersion behavior for sio2 at 26oc(graded index) 1.1 1.2 1.3 1.4 1.5 1.6 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 wavelength d is pe rs io n, p s/ nm .k m dispersion behavior for aluminosilicate glass at 26oc(graded index) 1 1.1 1.2 1.3 1.4 1.5 1.6 -50 -40 -30 -20 -10 0 10 20 30 40 wavelength d is pe rs io n, p s/ nm .k m dispersion behavior for vycor glass at 26 c(graded index) 1 1.1 1.2 1.3 1.4 1.5 1.6 -2.2 -2 -1.8 -1.6 -1.4 -1.2 -1 -0.8 -0.6 wavelength d is pe rs io n, p s/ nm .k m waveguid dispersion for vycor glass at 26 c(graded index) figure (16) dispersion behavior for aluminosilicate at t=26ºc (graded index) figure (17) waveguide dispersion for vycor at t=26ºc (graded index) figure (18) dispersion behavior for vycor glass at t=26ºc (graded index) t m w t m w t m w µm µm µm µm µmµm 7-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۸ temperatures behavioure of some alloy steels in turning process under different oprating conditions. asmaa a. kawi department of mechanical engineering, college of engineer university of basrah /basrah/iraq abstract based on three-dimension transient heat diffusion equation a fem model was developed to simulate coupled thermo-mechanical deformation effects on temperature behavior for four alloys steel during turning process . alloys used as a workpiece were aisi 1045, aisi 1030, aisi 4340 and aisi 4140, parameters such as cutting speed, feed rate were changed to explore their effect on temperature behavior. the results show that finite element method is a successful technique to perform analysis to estimate cutting temperatures, a possibility of developing temperature forms adequately representing metal cutting temperature as a polynomial models of third, fourth and fifth degree with time that give steady state temperature and for the four alloys steel used and different operation conditions. all alloys have a sever increasing temperature with increasing feed rate, while it looks less sharp with increasing cutting speed .also the ratio of the number of nodes have maximum temperature for any operating conditions and any alloy used with respect to the total number of nodes is less than 1%. keywords: turning process, alloys steel, steady state temperature, work-piece temperature, fem / // 3d – . aisi 1045, aisi1030, aisi 4340aisi 4140 . . . . مختلفة al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۹ . ١.% nomeclature introduction metal cutting operations still represent the largest class of manufacturing operations where turning is the most commonly employed material removal process (karpat). alloy steels are pronounced as difficult to cut materials and this can be hardened by regular process (derakhshan, 2009).turning of these types of alloys require a knowledge of coupled deformation and thermal turning simulation of work piece. intelligent design of tool and other process parameters is a key factor for effective processing (to get proper dimensions, internal deformation and microstructure distribution) and ensuring that the required product properties are achieved according to customer specifications. due to more demanding manufacturing systems, the requirements for reliable technological information have increased. this calls for a reliable analysis in the cutting zone (tool–work piece– chip system) (haci saglam, 2006). metals cutting are associated with high temperatures and hence the thermal aspects of the cutting process strongly affect the accuracy of the machining process. the high temperatures generated in the deformation zones have serious consequences for both the tool and the work-piece. cutting temperatures strongly influence tool wear, tool life, work-piece surface integrity, chip formation mechanism and contribute to the thermal deformation of the cutting tool (abukhshim,2005) and (rogério,2009). the chip formation process in machining is accompanied by heat generation, which influences the mechanical and physical properties of both the work-piece and the cutting tool (vincent and others, 2004). the unique tribological contact phenomenon, which occur in metal cutting is non-linear, and occurs at high temperatures, high pressures and high strains. this has made it extremely difficult to predict in a precise manner or even assess the sample initial yield strength of the material at room temperature and a strain rate of 1/sec a dimensionless constant for each materialb,c,d,e ,m and n heat capacitycp feed ratef frictional stressfs heat convection coefficienth thermal conductivityk interface pressure between two bodiesp heat loss due to free convectionq temperaturet room and melt temperaturest∞, tmelt depth of cutt1 cutting speedv densityρ material parameterα flow stress. strain strain rate reference strain rate al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۰ performance of various models developed for modeling the machining process. an accurate and repeatable heat and temperature prediction remains challenging due to the complexity of the contact phenomena in the cutting process. measuring temperature and the prediction of heat distribution in metal cutting is extremely difficult due to a narrow shear band, chip obstacles, and the nature of the contact phenomena where the two bodies, tool and chip, are in continuous contact and moving with respect to each other (abukhshim, 2006 ). therefore, numerous attempts have been made to approach this problem with different methods including experimental, analytical and numerical analysis using different workpiece materials specially alloy steel. a model to analyze the heat transfer and temperature distribution in rotary tool turning of hardened 52100 steel (58 hrc) was developed based on the moving heat source theory of conduction and employs the finite element method (fem) for its solution (vincent and others, 2004). a comparison study between the measured and calculated results of cutting force components and temperature variation generated on the tool tip in turning for different cutting parameters and different tools having various tool geometries while machining aisi 1040 steel hardened at hrc 40 (haci ,2006). a low carbon steel (c15) and a low alloyed medium carbon steel (42crmo4) was machined experimentally and the performances of the measurement setup are completed by the possibility of recording real time photographs of the chip formation (sutter, 2007). these records make the analysis of temperature maps easier and allow specific parameters as the contact length at the tool-chip interface or the shear angle to be determined. the effects of insert design in turning of steel parts and surface finishing has been investigated in finish turning of aisi 1045 steel using conventional and wiper design inserts (özel ,2009). regression models and neural network models were developed for predicting surface roughness, mean force and cutting power. a computational model to determine the temperature distribution in a metal cutting process based on multi-dimensional steady state heat diffusion equation along with heat losses by convection film coefficients at the surfaces was studied using the finite element method (pradip, 2005). results were presented for the machining of high-speed carbon steel and for a range of cutting conditions. an estimation of the amount of heat flowing into the cutting tool in high speed turning of aisi/sae-4140 was achieved experimentally (abukhshim, 2005). the aim is to characterize the thermal field in the cutting zone and thus understand the mechanics of high speed machining. prediction of heat generation, heat partition and temperature distribution in metal machining includes an exploration of the different simplifying assumptions related to the geometry of the process components, material properties, boundary conditions and heat partition was studied theoretically and experimentally (abukhshim, 2006). the work presented the results of extensive cutting tests performed to measure temperature along the tool-chip interface line when machining bs 970-709m40en19 (aisi/sae-4140) high strength alloy steel. the thermal problems in dry orthogonal turning devoted to c45 medium carbon steel with natural contact tools treated with multi-layer coatings with an intermediate al2o3 layer (grzesik, 2006). new hybrid analytical models for estimating heat partition to the chip and the tool–chip interface temperatures were proposed to estimate the average and maximum steady-state tool–chip interface temperatures in orthogonal turning. modeling of the tool temperature distribution was addressed in self-propelled rotary tool (sprt) machining of hardened steels (vincent, 2004). this model was developed to analyze the heat transfer and temperature distribution in rotary tool turning of hardened 52100 steel (58 hrc). the model is based on the moving heat source theory of conduction and employs the finite element method (fem) for its solution. a moving heat source along the surface of a half space was used to simulate the turning operation (jing, 2005). 3d square source problems are solved numerically by using finite element analysis. the surface temperature distribution inside and outside the contact area and the temperature distribution in the medium are obtained. most of the efforts in studying heat transfer have been directed toward determining temperature distributions in the chip and tool. in contrast, little attention was focused on the direct evaluation of the heat transfer process in the work-piece, either experimentally or theoretically. furthermore, mechanical properties of the work-piece such as tensile strength, work-piece surface integrity and hardness need to be correlated with microstructural parameters which effected in a sharp by workal-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۱ piece temperature. in this study a finite element computational model to determine temperature distribution in the work-piece, tool and chip in turning process was developed. the model is based on 3d unsteady state heat diffusion equation along with heat losses by convection coefficients at the surfaces. four different alloy steel were machined by using one kind of tool inserts, under various operating conditions. a parametric study will be carried out to investigate the effect of operating conditions on the temperature rise distribution, maximum and steady state temperature of the work-piece. thermal phenomena in simulation of mechanics of 3d turning turning is a very important machining process in which a single point cutting tool removes unwanted material from the surface of a rotating cylindrical work piece. the cutting tool is fed linearly in a direction parallel to the axis of rotation. three cutting parameters namely cutting speed(v) , feed rate(f) and depth of cut(t1) need to be optimized in a turning operation (abhang, 2010),as shown in fig(1-a). analysis of the thermal fields in turning process has been the topic of research interest for many years. it is a complex problem, involving many parameters and is too cumbersome to be truly simulated in any mathematical form (sarat, 2005). the main regions where heat is generated during the orthogonal cutting process are shown in fig. (1-b), firstly, heat is generated in the primary deformation zone due to plastic work done at the shear plane. the local heating in this zone results in very high temperatures, thus softening the material and allowing greater deformation. secondly, heat is generated in the secondary deformation zone due to work done in deforming the chip and in overcoming the sliding friction at the tool-chip interface zone. finally, the heat generated in the tertiary deformation zone, at the tool work-piece interface, is due to the work done to overcome friction, which occurs at the rubbing contact between the tool flank face and the newly machined surface of the work-piece. heat generation and temperatures in the primary and secondary zones are highly dependent on the cutting conditions (abukhshim, 2006). while for the tertiary region that depending on the friction modelling, which required an accurate model definition. the amount of heat generate in the work-piece resulting in a highly localized thermo mechanically coupled deformation in the shear zone. temperatures in the cutting zone considerably affect the stress–strain relationship, fracture and the flow of the work-piece material. generally, increasing temperature decreases the strength of the work-piece material and thus increases its ductility. it is now assumed that nearly all of the work done by the tool and the energy input during the machining process are converted into heat (abukhshim, 2006). problem formulation and boundary conditions the tool geometry and the cutting conditions used for the orthogonal metal cutting simulation are presented in table 1. during the cutting process, force exerted by the tool is converted into heat at a contact area between the tool edge and the chip which diffuses throughout the cutting tool and work-piece by conduction process according to the heat transfer equation for a three dimensional problem for unsteady state: (ρcp) ∂t/∂t= k (∂2t/∂x2+ ∂2t/∂y2+ ∂2t/∂z2) (1) where k is the thermal conductivity , t temperature, t time, ρ density ,cp heat capacity x perpendicular length , y the moving direction of the tool and z is the depth of work-piece. machining is performed at ambient temperature assuming the initial temperature of whole model at room temperature, t(x, y, z, t)= t(x, y, z, 0)=20˚c .the exterior boundaries of the tool-workpiece are exposed to the air; except at the tool–chip contact area, which are exposed to the environment, heat loss due to convection (h=20 w/m2 ˚c) is considered as shown in fig.2 where the elements marked in green are affected by free convection. q=h (t-t∞) (2) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۲ the far end surface of the tool holder and work-piece, which are distant from the cutting zone, is assumed to be at room temperature (t∞=20 ˚c). in contact area the frictional law is usually based on the coulomb model, eq. (3), with a constant friction coefficient, these laws are often modified with more realistic models, in which a constant shear model, eq. (4), is used to describe the phenomenon close to the tool tip (sticking zone), while a coulomb model properly fits in the complementary area of the contact length (sliding zone) (deform-3d user manual, 2007). fs = m τ (3) fs =μp (4) where fs is the frictional stress, m is the friction factor, τ is the shear yield stress, μ is the friction factor and p is the interface pressure between two bodies . the bottom surface of the work-piece is fixed in all directions. the cutting tool is modeled as a rigid body which moves at the specified cutting speed. tungsten carbide (wc) insert was used in this study as the cutting tool. the material-constitutive laws often include the effect of strain (rigid–plastic or elastic–plastic), strain rate (rigid–viscoplastic or elastic–viscoplastic) and temperature (thermal softening). deform 3d uses oxley’s equation, eq. (5), which used to express the flow stress relation and johnson–cook law, eq. (6) (deform-3d manual, 2007). eqs (5) and (6) are linking the flow stress to the strain, strain rate and temperature, are the most popular and widely used to develop numerical models of the cutting process and represent the material flow stress behavior under the machining condition in this study. unfortunately, for only a few low carbon steels is such a documented relationship available. for high carbon content steel or their hardened products, such as aisi h13 steel and (hardened) 52100 bearing steel, there are no such available documented constitutive equations that are required as the inputs for oxley’s predictive machining theory ,for that we chose this four alloy in this work. (5) (6) where )(* roommelt room tt tt t the constant a is in fact the initial yield strength of the material at room temperature and a strain rate of 1/sec and ε represents the plastic equivalent strain. temperature term in the j-c model reduces the flow stress to zero at the melting temperature of the work material is the flow stress, is the strain rate and t is temperature. parameters of the johnson–cook equation (c, d, e, m, and n are dimensionless constant for each material).the thermal conductivity, heat capacity and thermal expansion properties for alloys chosen are changing with temperature. the properties of alloy steel studied in this work are listed in table 2. finite elemnt modelling modeling 3d cutting process using finite element techniques is an area of ongoing research activity due to significant cost savings and offers insights into the process which are not easily measured in experiments, . in particular heat transfer and the modeling of cutting process requires careful consideration in any modeling activity. this paper presents approaches for modeling the turning process for four types of alloy steel. in this study, a finite element analysis software deform 3d is used to study the effects of cutting speed, feed rate, and type of alloy steel in temperature behavior. the work-piece is modeled as elastic-plastic material to take thermal, elastic, plastic effect. work-piece is represented by a liner model with different length for each condition. ),,( t }{])][ln(1)[( *mn etdcba al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۳ the short material length was chosen to save computational time without compromising the model integrity as heat generation in machining is confined in small areas around the cutting zone. the work-piece shape is constructed by the deform machining module, and includes geometry created by a previous tool pass, including appropriate depth of cut and nose radius details. an unstructured tetrahedral finite element mesh was generated using deform’s automatic mesh generation system. re-meshing parameters, including minimum element size, and parameters for adaptive mesh definition are set within the system. for these procedures of the simulations, a minimum element size of 0.25 of the fed rate was specified. the total number of elements was 100000 to 130000 depending upon work-piece size. the lagrangian calculation embeds a computational mesh in the material domain and solves for the position of the mesh at discrete points in time. an incremental lagrangian formulation with an implicit integration method designed for large deformation simulations is used to simulate the cutting process. the solver used was the sparse matrix with a direct integration method, because the conjugate-gradient offers an improved computational speed but less stability in convergence. result and discussion a comparison between the constructed model presented in this work with experimental data and computed values of the average cutting temperature data using advantede pl-td fem simulation predicted by(grzesik ,2008) is presented in fig.(3). taken same conditions used in this reference .i.e. cutting speeds of (103.2, 206.4, 330 m/min), feed rate of 0.16 mm/rev and depth of cut of 2 mm with aisi 1045 work-piece material and iso p20 uncoated carbide tool. thermal properties (k, cp, and ρ) for tool material taken from ref.( umbrello,2007). fig.(3) shows good agreement between experimental date of ref.( grzesik , 2008)and present fe model for the three selected cutting speeds with percentage error of (3.75, 7.03, and 2.616)% for speeds 103.2, 206.4, and 330 mm/min respectively. assuming that the cutting region apply as moving heat source, along the surface of the workpiece in the +y direction , see fig.(4), that means the maximum temperature absolutely lay near this region ,since maximum friction , interface pressure between tool and work-piece, and shear stress lay in this region. but it's behavior with time differs, in the early stage of the cutting process, only the heat transferred is absorbed, resulting a rapid increase in the local temperature, after that the heat transferred is partially absorbed to raise its enthalpy and is then partially diffused into the neighboring domain assume there is no convection under the tool because the solid surface of the work-piece is covered by the tool (just near cutting zone i.e zone of maximum temperature). that’s mean maximum amount of heat will transfer by conduction to the work-piece and tool neglecting heat transfer by radiation. this results in a temporarily increase in the local temperature which then nearly approaches its final steady value, since the amount of work done on the workpiece is constant with fixed cutting velocity and feed rate, as shown in fig.(5). fig. (5) shows temperature response for cutting aisi 1045, aisi 1030, aisi 4340 and aisi 4140 steel. it is disclosed that the temperature response is temporally and approximately exponential with fluctuations, the amplitude of the fluctuations differs for each other depending on the thermal properties and internal composition of each one (chromium, manganese, molybdenum, phosphorus, silicon and sulphur ) specially the rate of (sulphur) which increase machining capability then reducing shear effect , finally reducing the cutting temperature. the extent of temperature oscillations varies with the work materials which are most severe in cutting aisi 1030 then aisi 4140, aisi 4340 and aisi 1045 steel. these temperature fluctuations are caused by chip formation, which raises the local temperature upon contact with the tool material. the difference in the extent of temperature oscillations can be attributed to the differences in chip size during machining operations and the properties of the work-piece materials. the data drawn in fig (5) can be fitted as a time polynomials (applies in the earlier stages till 3msec which gives steady state temperature) for each alloy at the different conditions can be arranged in table (3). it is clearly from fig.(5) that steady state may reaches depending on the operating conditions ,it has an inversely proportion with operating conditions. maximum time may need to reach steady al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥٤ state starting 1.11msec for low conditions to 2.8 and 3msec for medium and high conditions respectively. also these values differ from alloy to other that aisi 1045 need less time followed by aisi 4340, aisi 4140 and aisi 1030 to reach steady state. figs (6) and (7) depicts the effects of feed and cutting speed on the steady state temperature for the four alloys respectively at a constant depth of cut(1mm). they are essentially a plot of the temperature equation variation. for a constant cutting speed 53.4 m/min fig. (6), of v= 54.4m/min, all alloys have a sever increasing in temperature with increasing feed rate, since increase in feed rate lead to increasing the section of chip and consequently friction increases as reported by shaw in (jing, 2005).the sensibility to cutting process change with increasing feed rate differs from alloy to other depending to shearing force and machining capability for each one. aisi 1030 and aisi 4140 have higher cutting temperature curve than aisi 4340 and then aisi 1045 with increasing feed rate ,these arrange for the four alloys repeat for each cutting speed figs.(6),v=103.2 ,206.4 and 330 m/min, except the coincidence between aisi 1030 and aisi 4140 ,these appear coincides at cutting speed 53.4 m/min and any range of feed rate because of rapprochement in thermal properties fig.(6) of v=53.4 m/min , then starting contrast between this alloys with increase cutting speed fig (6) v=103.2 ,206.4 and 330 m/min ,for appearing the effect of chemical composition with increasing cutting temperature by increasing cutting speed. the same tendency appears in fig. (7), for the effects of cutting speed on the steady-state temperature for all work-piece alloys. except that the behavior for the steady state temperature looks less sharp and has exponential form even with low feed rate fig. (7), of v=53.4m/min). that's mean the liner trend caused by low cutting speed not feed. the same word may say for the behavior of aisi 4140 and aisi 1030, the congruity present only in low cutting speed region but not low feed. also arrangement of alloys machining acceptability dos not effected, that’s aisi 1045 then aisi 4340, aisi 4140 lastly aisi 1030. temperature is closely connected to cutting speed, with increase of cutting speed friction increases; this induces an increase in temperature in the cutting zone. also the percentage of the number of nodes which have range of temperature with respect to total number could be calculated directly in 3d-deform. so comparison made in fig.(8) among alloys shows the range of temperatures distribution in each alloy for cutting speed 220.4 m/min ,feed rate =0.2 mm/rev and 1mm as a depth of cut. percentage of nodes have ranges of maximum temperature covers minimum ratio of nodes number reach to (0.745, 0.836, 0.583, 0.613) % for aisi 1045, aisi 4340, aisi 4140 and aisi 1030 respectively. conclusions the following conclusions could be drawn from the results of present study: 1) finite element method using deform 3d program is found to be a successful technique to perform trend analysis to estimate cutting temperatures in metal cutting with respect to various combinations of design variables (metal cutting speed, feed rate and depth of cut). 2) polynomial models of third, fourth and fifth degree are found to be adequately representing metal cutting temperature results with time applies in the earlier stages till 3msec to give steady state temperature for different operating conditions and for aisi 1045, aisi 4140,aisi 4340 and aisi 1030 alloys steel. 3) steady state temperature may reach in time less than 3 msec depending on alloy steel properties and operating conditions. 4) all alloys have a sever increasing in steady state temperature with increasing feed rate, while it looks less sharp and has exponential form with increasing cutting speed . 5) a coincidence in steady state temperature curve between aisi 1030 and aisi 4140 appear at cutting speed 53.4 m/min and any range of feed rate, then starting contrast between this alloys with increase cutting speed . 6) percentage of number of nodes which have range of temperature respect to total number for all alloys seems closely convergent but not the temperature which respected by this ranges. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥٥ refrenses -abhang, l. b. and hameedullah m. , "power prediction model for turning en-31 steel using response surface methodology", journal of engineering science and technology review ,3 (1), 116-122,2010. abukhshim, n.a , mativenga, p.t, sheikh, m.a.," heat generation and temperature prediction in metal cutting: a review and implications for high speed machining" ,international journal of machine tools & manufacture ,46,782–800, 2006. abukhshim, n.a , mativenga, p.t, sheikh, m.a. ," 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journal of machine tools & manufacture, 44 ,1463–1470,2004. www.mat-lab.com -yang w.h and tarng y.s.," design optimization of cutting parameters for turning operations based on the taguchi method", journal of materials processing technology, 84, 122–129, 1998. table (1) summary of cutting conditions tnma 332flat insert -5rake angle -5clearance angle 53.4 ,103.2 , 206.4, 330 m/minv 0.05, 0.15, 0.2 mm/rev f 1 mmt1 aisi 1045, aisi 1030 ,aisi 4340, aisi 4140 steelworkpiece 0.5coulomb friction coefficient wc uncoutedtype of cutting tool 59 n/sec/ktool thermal conductivity (k) 15 n/mm2/ktool heat capacity (cp) 15800 kg/m³tool density (ρ) table (2) physical properties of workpiece alloys (www.mat lab .com) and (deform-3d manual,2007) aisi 4340 aisi 4140 aisi 1045 aisi 1030property 41.7(at 20 °c) to43.4 (at 100oc )to 34.1oc at (t≥600oc) from 41.9(at 20 °c) to22.5 at(t>850oc) from 41.9(at 20 °c) to22.5 at (t>850 oc ) from 46.8 (at 20 °c) to 31.74 (at 700 °c) to25.09 at (1000oc) thermal conductivit y (k) from 3.6(at 20 °c) to 6.1(t≥600 °c from 3.6(at 20 °c) to6.1(t≥600 °c) 3.6(at 20 °c) 6.1(t≥600 °c from 3.35 (at 20 °c) to 7.2 (at 1000 °c) heat capacity (cp) n/mm2/k 7850783078607850density(ρ) kg/m³ 0.30.30.30.3poisson’s ratio from 212 (at 20 °c ) to 130 (at 900 °c) young’s modulus (e) (gpa) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۷ table (3) time polynomials for each alloy steel at the different conditions formula*operating condition type of alloy steel t=3*1011t3-8*108t2+9.25*105t+tihigh t=-4*1013t4+3*1011t-7*108t2+9*105t+timedium t=9*1010t3-3*108t2+4.5*105t+tilow aisi 1045 t=-8*1014t4+3*1012t3-4*109t2+2*106t+tihigh t=9*1016t5-5*1014t4_+1012t3-2*109t2+106t+ timedium t=-2*1013t4+2*1011t-5*108t2+7*105t+tilow aisi 4340 t=1018t5-4*1015t+7*1012 t3-6*109 t2+3*106+ tihigh t=7*1016t5-4*1014t4+1012t3-2*104t2+106t +timedium t=-3*1013t4+3*1011t-9*108t2+9.12*105t+tilow aisi 4140 t=7*1017t5-3*1015t4+6*1012t3-6*109t2+3*106t+tihigh t=1017t5-6*1014t4+2*1012t3-2*109t2+2*106t+ timedium t=-5*1019t6 +6*1017t5-2*1015t4+4*1012t3-4*109t2 +2*106t +ti low aisi 1030 * high operating conditions f=0.2 mm/rev, v=330 m/min ; medium operating conditions f=0.15mm/rev, v=103.2 m/min; low operating conditions f=0.05mm/rev, v=53.4 m/min. (a) (b) fig.(1) turning process (a) basic cutting parameters (yang ,1998). (b)thermal fields (abukhshim, 2006). conduction radiation al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۸ fig. (2) boundary conditions on the workpiece. constant temperature fraction and shear zone fig.(4) temperature distribution on cutting surface of workpiece of aisi 1030,v=330m/min, f=0.05rev/min, d=1mm after 0.000364sec from starting cutting. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۹ (a) (b) (c) fig. (5) comparison of temperature response in early and beginning of steady stages for workpieces used; (a) at low operating conditions f=0.05mm/rev, v=53.4 m/min ; (b) at medium operating conditions f=0.15mm/rev, v=103.2 m/min; (c) at high operating conditions f=0.2 mm/rev, v=330 m/min. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۰ v=53.4 m/min v=103.2 m/min v=206.4 m/min v=330 m/min fig.(6) effects of feed rate on steady-state temperature in the work materials at different cutting speed al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۱ f=0.05 mm/rev f=0.15 mm/rev f=0.2 mm/rev fig. (7) effects of cutting speed on steady-state temperature in the work materials for different feeds al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۲ fig. (8) histogram shows the percentage of nodes with its temperature range for workpiece of 8mm length after cutting time 0.00181 sec. p er ce nt ag e of n od s% temperature ◦ c (c) aisi 4140 p er ce nt ag e of n od s% temperature ◦ c (a) aisi 1045 p er ce nt ag e of n od s% temperature ◦ c (b)aisi 4340 p er ce nt ag e of n od s% temperature ◦ c (d)aisi 1030 ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٣ دراسة تأثیر إضافة ألیاف التقویة على بعض الخواص المیكانیكیة للمواد المركبة المتقدمة علي إبراهیم الموسوي بابل–المعهد التقني لمانعلي جاهل س بابل–المعهد التقني الخالصة یهــدف البحــث الحــالي إلــى دراســة بعــض المفــاهیم والخــواص المهمــة فــي تصــنیع المــواد المركبــة المتقدمــة ذات أســاس بــولیمیري والمقــواة باأللیــاف ، حیــث تعتبــر المفــاهیم مقدمــة لــبعض الخــواص المهمــة للمــواد البولمیریــة الشـــد (ب مكوناتهـــا مـــن األلیـــاف والمـــادة األســـاس وبعـــض الخـــواص المیكانیكیـــة المقـــواة باأللیـــاف والمتعلقـــة بنســـ یتنــاول هــذا البحــث إضــافة نســب وزنیــة مختلفــة مــن ألیــاف ) . ،الصــدمة ،اإلنضــغاط ،اإلنثنــاء ،الصــالدة وغیرهــا أثیر هذه والمستخدمة في تقویة راتنج الفنیل أستر وت(g/cm2 340)كیفالر أحادیة اإلتجاه ذات كثافة سطحیة اإلضــافة علــى الخــواص المیكانیكیــة لهــذا الــراتنج وقــد شــملت هــذه الخــواص كــل مــن مقاومــة الصــدمة والشــد و اإلنضغاط و اإلنثناء والصالدة حیث تم في البدایة إستخراج الخواص المیكانیكیة لراتنج الفنیـل أسـتر قبـل تقویتـه و دراسـة تـأثیر (20%,40%,60%)ف كیفالر إلى الراتنج باأللیاف بعدها تم إضافة نسب وزنیة مختلفة من ألیا .ذلك على الخواص المذكورة .المادة المركبة المتقدمة ، الخواص المیكانیكیة : الكلمات الدالة study the effect of reinforcing fibers on some mechanical properties of advanced composite materials ali j. salaman technical institute-babylon ali i. al-mosawi technical institute-babylon ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٤ abstract this research aims to study some aspects and important properties in manufacturing of polymeric advanced composite materials reinforced by fibers will be studied ,these aspects show as introduction to some important properties of polymeric composite materials reinforced by fibers related with its composition and some mechanical properties (tension ,impact, compression, flexural, etc) .the objective of this research is to study the effect of using different reinforcement percentage of fibers on mechanical properties for composite material consist of vinyl ester resin reinforced by unidirectional kevlar fibers with surface density (340 g/cm2) which included impact , tensile, compression , and flexural strength , where we extracted the mechanical properties for vinyl ester resin before reinforced by fibers, then we reinforced the resin by different weight percentage from kevlar fibers (20%,40%,60%) and studied its effect on the above mechanical properties . . (introduction)المقدمة المقـواة باأللیـاف ذات أسـاس (advanced composite materials)تم تطویر المـواد المركبـة المتقدمـة إن الهــــدف . بـــولیمیري للتطبیقـــات التـــي تحتــــاج الجمـــع اإلســـتثنائي بـــین المقاومــــة ، الجســـاءة ، والـــوزن الخفیـــف الرئیســي مــن التقویــة باأللیــاف هــو لتحســین الخــواص الفیزیائیــة ومنهــا الخــواص المیكانیكیــة للراتنجــات حیــث تــزداد مقاومة الشد والصدمة والصالدة بشكل كبیر مما یسمح بإسـتخدام هـذه المـواد المقـواة فـي مجـاالت صـناعیة أوسـع المواد المركبة هي المسؤول الرئیسي عن تحمل األحمال إن األلیاف في هذا النوع من. ]١[وتحت ظروف أقسى الخارجیة ، ومن أكثر أنواع األلیاف شیوعًا في مجال المواد المركبة المتقدمة هي ألیاف كیفالر والكاربون وألیاف ذه المواد إن اإلستخدام العام للمادة المركبة یعتمد بشكل كبیر على الخواص المیكانیكیة والفیزیائیة له. ]١[كیفالر لذلك فإن دراسة هذه الخواص تحـت تـأثیر القـوى واألحمـال فـي ظـروف مختلفـة یكتسـب أهمیـة كبیـرة لمعرفـة مـدى هنالك أربعة أنواع من المواد المركبـة المتقدمـة والمدرجـة أدنـاه . ]٢[مالئمة هذه الخواص لمكان عمل هذه المواد ]٣[ : تســتخدم ألیــاف ذات عالیــة المقاومــة :(resin-matrix composites)المــواد المركبــة راتنجیــة األرضــیة -١ .(315ºc)ومعامل المرونة مثل ألیاف الكاربون إضافة إلى إمكانیة إستخدامها إلى درجة یمكــن إســتخدامها فــي درجــات حــرارة : (metal-matrix composites)المــواد المركبــة معدنیــة األرضــیة -٢ 1250)عالیة ºc)وبة هي المقاومة العالیة مقرونة مع المطیلیة والمتانة حیث الظروف المطل. تتحمـل هـذه المـواد درجـات حراریـة : (carbon-carbon composites)كـاربون -المـواد المركبـة كـاربون-٣ 3300)عالیة تصل إلى ºc) ٣٠(مع مقاومة أعلى بعشرین مرة من الكرافیت التقلیدي وأقل كثافة بنسبة. (% تتصــف هــذه المــواد بــالوزن الخفیــف ومقاومــة : (ceramic composites)ة الســیرامیكیة المــواد المركبــ-٤ ستقراریة في األبعاد وعدم تأثرها بالظروف البیئیة ٕ .درجات الحرارة العالیة وا ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٥ .(the properties of composite materials)خواص المواد المركبة ســیة للمـواد المركبــة إلــى حـد بعیــد علـى خواصــها الفیزیائیـة ومنهــا الخــواص تعتمـد اإلســتخدامات العامـة والهند المیكانیكیة والفیزیائیة مثل مقاومة الشد والمرونة وقابلیة المادة لإلستطالة ومقاومتها للحرارة والظروف البیئیة مثـل تمـــد كثیـــرًا علـــى إن جمیـــع هـــذه الخـــواص تع. الرطوبـــة وأشـــعة الشـــمس وغیرهـــا مـــن الخـــواص التطبیقیـــة اُألخـــرى تعتمـد هـذه الخـواص إلـى حـد كبیـر علـى . ]٤[التركیب الجزیئي للراتنج وعلى وزنه الجزیئـي وعلـى القـوى الجزیئیـة :ومن الخواص التي تمت دراستها ما یأتي . مواد التقویة وعلى المواد المضافة مثل الحشوات والملدنات اومة الصدمة عن قـدرة المـادة لمقاومـة الكسـر تحـت تـأثیر ُتعبر مق: (impact strength)مقاومة الصدمة -١ حمل مفاجئ ، كما تعتبر مقیاسًا لمتانة المادة حیـث المـواد األكثـر متانـة هـي التـي تبـدي أعلـى مقاومـة للصـدمة ]٥[. تعتبــر مقاومــة الشــد مقیاســًا لقابلیــة المــادة علــى مقاومــة القــوى: ( tensile strength)مقاومــة الشــد -٢ نهیارها ٕ تتكون المواد المركبة اللیفیة من ألیاف قویة هشة مغمورة فـي المـادة . الساكنة التي تحاول سحب المادة وا .]٦[األساس التي تتصف بكونها أكثر مطیلیة تبین هذه المقاومة مدى تحمل المادة عند تعرضها إلـى : (compressive strength)مقاومة اإلنضغاط -٣ والقـیم العالیـة ُتشـیر إلـى كبـر قـوى التماسـك (mpa)قبل أن تنهار ، وتقـاس عـادة بوحـدات حمل إنضغاط ساكن . ]٧[بین جزیئات المادة وتعتبر هذه الخاصیة مقیاسًا لمقاومة اإلنحنـاء ، ویمكـن تعرفهـا : ( flexural strength)مقاومة اإلنثناء -٤ تبــار قبــل أن یخضــع أو ینكســر وتقــاس بوحــدات علــى إنهــا أقصــى حمــل ســاكن یمكــن تســلیطه علــى نمــوذج اإلخ (mpa)]١.[ .(partial experiment)الجزء العملي یتضمن الجزء العملي إعـداد المـواد األولیـة إضـافة إلـى اإلختبـارات المیكانیكیـة التـي تـم إجراءهـا علـى المـادة .المركبة .المواد المستخدمة في البحث -أوالً :لبحث المواد التالیةإستخدمت في هذا ا ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٦ -deraken 510)تم إستخدام راتنج الفنیل أستر نـوع :( vinyl ester resin)راتنج الفنیل أستر -1 a40) ذو كثافـــة(1.21g/cm3) المجهـــز مـــن شـــركة و(dow chemical). یوضـــح تركیبـــه )١(الشـــكل رقـــم .الكیمیائي ) ٠°(اف كـیفالر بشـكل ظفـائر محاكـة أحادیـة اإلتجـاه إسـتخدمت ألیـ:(kevlar fibers)ألیـاف كـیفالر -2 .(340g/cm2)ذات كثافة سطحیة .(preparation of samples)تحضیر النماذج -ثانیاُ نعت أربعة أنواع من النماذج خاصة باإلختبارات التي تم إجراءها وهي :صُ ، (astm-e23)اصـفات القیاسـیة تم تصنیع نمـاذج إختبـار الصـدمة حسـب المو :نماذج إختبار الصدمة -١ ُأستخدم ) .º٤٥(وبزاویة حز مقدارها (mm 0.25)ونصف قطر قاعدة الحز(mm 0.5)عمق الحز في النماذج للتعرُف على مدى مقاومة المادة (charpy impact instrument)جهاز فحص مقاومة الصدمة نوع شاربي مل الصدمة . المركبة لِح في تصنیع نماذج إختبار مقاومة (iso-r-527)إعتمدت المواصفة القیاسیة :ة الشدنماذج إختبار مقاوم-٢ zhejinang tugong) (instrument co., ltdإستخدم جهاز اإلختبارات العام والمجهز من شـركة . الشد مل . (kn 20)الصینیة في قیاس هذه الخاصیة بِح -astm)تم تصنیع نمـاذج إختبـار مقاومـة اإلنضـغاط حسـب المواصـفة:إلنضغاطنماذج إختبار مقاومة ا-٣ d618) إســتخدم مكــبس هیــدرولیكي نــوع . وهــي بشــكل منشــور ربــاعي(leybold harris no.36110) لتعیــین أقصــى حمــل إنضــغاط یتحملــه النمــوذج وبقســمة هــذا الحمــل علــى مســاحة مقطــع النمــوذج قبــل التشــوه تــم .نضغاط للنماذج كافة إحتساب مقاومة اإل في تصنیع نماذج اإلختبار (astm d790)ُأعتمدت المواصفة القیاسیة : نماذج إختبار مقاومة اإلنثناء -٤ تم قیاس مقاومة اإلنثناء بطریقة اإلختبار . (10mm×135mm)والتي كانت على شكل نماذج مستطیلة بأبعاد (leybold harris no.36110)یكي متعدد األغـراض نـوع ثالثي النقاط ویتم ذلك بإستخدام مكبس هیدرول .لقیاس أقصى حمل مسلط على منتصف نموذج اإلختبار لتصــنیع نمــاذج اإلختبــارات أعــاله وبواقــع (20%,40%,60%)ُأضــیفت نســب وزنیــة مختلفــة مــن ألیــاف كــیفالر . في النتائج إن وجدثالث نماذج لكل نسبة وزنیة وأخذ معدل القراءات لتقلیص اإلنحراف الحاصل ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٧ .(results and discussion)النتائج والمناقشة یوضــح قــیم مقاومــة الصــدمة مــع نســبة التقویــة باأللیــاف ، حیــث یالحــظ إنخفــاض مقاومــة )٢(الشــكل رقــم ر نتیجـة لكـون الصدمة لراتنج الفنیل أستر نظرًا لهشاشته ولكن هذه المقاومة تبدأ بالزیادة بعد تقویته بألیاف كـیفال . األلیـاف ســوف تتحمـل الجــزء األكبـر مــن طاقـة الصــدمة المســلطة علـى المــادة المركبـة ممــا ُیحسـن هــذه المقاومــة وهــذا یتفـق مــع مــا توصــل %) ٦٠(و %) ٤٠(وهكـذا تــزداد مقاومــة الصـدمة مــع زیــادة نســبة التقویـة باأللیــاف إلــى .مقاومة الصدمة بأن زیادة محتوى األلیاف یرفع] ٨[(ali)إلیه الباحث یمثل مقاومة الشد للمادة المركبة حیث تكون قیمـة هـذه المقاومـة منخفضـة جـدًا لـراتنج الفنیـل )٣(الشكل رقم أستر بسبب كونه من المواد الهشة ولكن عند إضافة األلیاف إلى هـذه المـادة تتحسـن مقاومتـه للشـد بصـورة كبیـرة تتحملـــه األلیـــاف ممـــا یرفـــع مقاومـــة الشـــد للمـــادة المركبـــة وذلـــك ألن حیـــث إن الجـــزء األعظـــم مـــن الجهـــد المســـلط ل األلیاف حیز . األلیاف تتمیز بمطیلیتها المنخفضة وتزداد مقاومة الشد بزیادة نسبة األلیاف المضافة حیث تشِغ مل المسلط علیها بشـكل أفضـل وهـو یتفـق مـع النتـائج التـي توصـ ل إلیهـا أكبر داخل الراتنج مما یسمح بتوزیع الِح ,abbas)الباحثین ali, sajed)]في كون إرتفاع قیمة مقاومة الشد بإضافة األلیاف إلى راتنج الفنیـل أسـتر ] ٩ . الـذي یمثـل إختبــار مقاومـة اإلنضـغاط للمـادة المركبـة حیــث یالحـظ منـه إرتفـاع قـیم مقاومــة )٤(الشـكل رقـم یـاف كـیفالر عمـا كانـت علیـه لـراتنج الفنیـل أسـتر ، حیـث مقاومـة اإلنضغاط للمادة المركبة الناتجة من التقویـة بأل مـل علـى األلیـاف وكـذلك كفـاءة الـربط اإلنضـغاط ترتفـع بشـكل حـاد عنـد التسـلیح بألیـاف كـیفالر نظـرًا لتوزیـع الِح ضـغاط وتـزداد مقاومـة المـادة المركبـة لإلن. بین المـادة األسـاس وألیـاف التقویـة ممـا ویرفـع قـیم مقاومـة اإلنضـغاط مع زیادة نسـبة األلیـاف المضـافة لـنفس السـبب المـذكور أعـاله وهـذا یتفـق مـع النتـائج التـي توصـل إلیهـا البـاحثین (abbas, ali, samara)]فـي تحسـن مقاومـة اإلنضـغاط لـراتنج الفنیـل أسـتر مـع إضـافة األلیـاف وزیـادة ] ١٠ .محتواها اء لراتنج الفنیل أستر المقوى بألیاف كیفالر حیث تكون قیمة الذي یمثل إختبار مقاومة اإلنثن)٥(الشكل رقم مقاومة اإلنثناء منخفضة قبل التقویة باأللیاف ، ولكن هذه المقاومة تبدأ باإلرتفاع لهذا الراتنج بعـد تقویتـه بألیـاف ء األكبـر مـن كیفالر ویعود السبب في ذلك إلى إرتفاع معامل مرونة هذه األلیاف مما یؤدي إلى تحملها إلى الجز . الحمــل المســلط علــى المــادة المركبــة ممــا یــؤدي بــدوره إلــى زیــادة مقاومــة اإلنثنــاء لهــذه المــادة المدعمــة باأللیــاف وتزداد هذه المقاومة مع زیادة نسبة التقویـة باأللیـاف وهـو یتفـق أیضـًا مـع النتـائج التـي تـم التوصـل إلیهـا مـن قبـل ,abbas)الباحثین ali, samara)]١٠.[ .(conclusions)اإلستنتاجات ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٨ :من خالل النتائج التي تم الحصول علیها یمكن الخروج باإلستنتاجات التالیة .كونه من المواد الهشة الفنیل أسترإنخفاض قیم الخواص المیكانیكیة لراتنج-١ . الر أحادیة اإلتجاه بعد تقویته بألیاف كیفالفنیل أسترتحُسن قیم هذه الخواص المیكانیكیة لراتنج-٢ .تزداد قیم الخواص المیكانیكیة مع زیادة نسبة األلیاف المضافة -٣ .(references)المصادر 1p. vincenzini and m. singh “advanced inorganic fibrous composites v ” , transtech publications, 2006 2p.k. mallick “fiber-reinforced composites: materials, manufacturing, and design”, 3rd edition , crc press, 2007. 3e.p.degarmo, j.t. black, and r.a. kohser “ materials and processes in manufacturing ” , 10th edition , john wiley & sons , 2008 . 4us industry forecasts to 2011 and 2016 “kevlar fibers”, freedonia , 2007. 5b.a.azhdar “impact fracture toughness of fiber reinforced epoxy resin” ,m.sc thesis ,u.o.t ,1992 . 6n.g.mccrum, c.p.buckley and c.b.bucknal “principal of polymer engineering” , second edition , oxford university press , 1997 . 7efunda engineering fundamentals “polymer material properties” ,2001. 8ali i. al-mosawi “study of some mechanical properties for polymeric composite material reinforced by fibers ” , al-qadessiyah journal for engineering science , vol 2 , no 1 , 2009 . pp.14 – 24 . 9abbas a. al-jeebory, ali i.al-mosawi, sajed a. abdul allah “effect of percentage of fibers reinforcement on thermal and mechanical properties for polymeric composite material ” , the iraqijournal for mechanical and materials engineering ,special issue, first conference of engineering college , babylon university ,17-18 may, 2009 , pp.70 – 82 . 10abbas a. al-jeebory, ali i.al-mosawi, samara a. al-qurashi “difference fibers reinforcement percentage and its effect on mechanical properties of thermosetting resins” , al-qadessiyah journal for engineering science ,special issue, second conference of engineering college , al-qadessiyah university ,19-20 october , 2009. ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٩ oh ch coh n ]١[یوضح التركیب الكیمیائي لراتنج الفنیل أستر) ١(الشكل رقم c=c-c-o c-cc-o-c-o-c-c-c-o-c-c=c o o مقاومة الشد ) : ٣(الشكل رقم reinforcing percentage (%) t en si le s tr en gt h (n /m 2 ) الصدمةمقاومة ) : ٢(الشكل رقم reinforcing percentage (%) im pa ct s tr en gt h (k j/m 2 ) 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 0 20 40 60 80 100 120 140 160 180 200 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 0 50 100 150 200 250 300 350 400 450 reinforcing percentage (%) c om pr es si on s tr en gt h (m pa ) مقاومة اإلنضغاط ) : ٤(الشكل رقم reinforcing percentage (%) fl ex ur al s tr en gt h (g pa ) مقاومة اإلنثناء :)٥(الشكل رقم 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 120 130 140 150 160 170 180 190 200 210 220 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24 2-2-2011.pdf قطر قطر نصف نصف .و، داخلي )isotropic ( .تكاملالكترك وبذلك ،.ال 10 )computational cost ( . للمرة األولىlefm . تم . مقارنة النتائج مع بحوث مماثلة تم للتحقق. in the recent year, a kind of meshless or meshfree method has been developed based on moving least square (mls) approximation [1], which does not require a structured mesh or elements. among these methods, element free galerkin method (efgm) [2-5] is particularly attractive, due to its uncomplicatedness, easing of numerical difficulties of mesh entanglement, faster rate of convergence, and a formulation that corresponds to well-established fem. because of the mls properties in the continuity, and the smooth approximation results, efgm use to extract the data in the discontinuities such as in the crack [6-10], and shear band [11-14]. one of the drawbacks of efgm is forced imposition of essential boundary conditions rather than the direct method. this is existed because of the mls does not have the kronecker delta property, where the shape function associated with a node is not exactly equal to one at this node, and this shape function is not exactly zero at the other nodes in the domain. this drawback is solved by using a variety of the enforced boundary methods [4, 15, 16]. in the mls approximation, each node has a domain of influence, in which a function of compact support is used as a weight function. the weight function determines the intensity of the effect of a node at various points in its domain of influence. figure 1 represents discretization using meshless methods: nodes, circular domains of influence. examples of commonly used test functions are exponential function, and spline functions. excellent details on systematic ways to construct weigh functions can be found in [15, 17-18]. the nodal influence domain is usually considered having a consolidated form in the shape of a circle or sphere. in the efgm, accuracy and effectiveness are dependent on the nodal domain of influence and type of the weight function. in this work, non-consolidated (anisotropic) weight function in the elliptic form is introduced to improve the efficiency of the efgm in some problems. in the using non-consolidated weight functions, the influence domain of each node may vary with direction. as a consequence, the definition of the influence domain based on non-consolidated weight function, improves the numerical efficiency of efgm. in such case, the influence domain of each node can be determined so that the nodal overlapping decreases. thus, good results can be achieved with less computational efforts. it has been shown that moving least-square methods and weight functions share many features for the constructing the approximation of the solution. in the mls technique that presented by [1], the approximation is expressed as the inner product of a vector of the polynomial basis and a vector of the coefficient . 1 (1) where denotes the number of terms in the basis. in two dimensions a complete polynomial basis of order m is given by ,...,,...,,...,,,,,,1, 22 (2) for bi-linear, the basis function is considered as ,,,1, , =4 (3) 11 also, the linear basis is provided by ,,1, , =3 (4) vector of unknown parameters that depended on is given as ,...,2,1 (5) these basis functions are not required to be polynomials as shown in equations 3 and 4. when solving problem involving cracks, a convenient way of capturing /1 stress-singularity in linear-elastic fracture mechanics is calculated by using [19,20] ,,,1, , =4 (6) or sin2cos,sin2sin,2sin,2cos,,,1, , =7 (7) where and are polar coordinates with the crack tip as the origin. equations 6 and 7 represent fully enriched and partially enriched basis functions, respectively. in the equations 1, the coefficient vector, is determined by minimizing a weighted discrete l2 norm, defined as 1 2 (8) where n is the number of nodes such that ;0 is the weight function associated with node which is non-zero over a limited support called the influence domain of node . furthermore, it is assumed that is non-increasing for 0 , where . the parameter determines the influence domain of node for weight functions. equation 8 can also be written as [15] (9) where ,...,, 21 (10) 1 1 1 2222 1111 (11) 12 00 00 00 2 1 (12) the stationarity of with respect to yields 0 (13) therefore, (15) 2211 the mls approximants can be defined as 1 (16) where the shape function is = 1 (17) the partial derivatives of can be obtained as follows 1 , 11 , 1 ,, (18) in which , . consider a two dimensional problem. by substituting the approximation in equation 16 into the associated galerkin weak form, one can obtain the final form of the discredited system of equations [2,15,20] 0 (19) where 13 (20) (21) (22) (23) where and are specified traction vector, body force vector, matrix of elastic constants and vector of lagrange multipliers, respectively. matrices and are defined as follows , , , , 0 0 (24) 0 0 (25) 0 0 (26) in equation (26), are the conventional fem shape functions which are used for the approximation of lagrange multipliers on the essentials boundaries [4, 15]. this is because as mention, the mls shape functions do not possess the kronecker delta function property. in the process of generation of the system of equation (19), two domain integrals must be computed. these integrals are involved in the stiffness matrix, equation (20), and load vector equation (22). usually in the efg method, these two integrals are computed by gaussian quadrature method [19]. the shape functions are obtained from the weight functions, these functions have influence domain of the node. the domain size is defined by the so called dilatation parameter or smoothing length. it is critical to solution accuracy, stability and plays the role of the element size in the finite element method. the final characteristics of weight functions are its functional forms. the weight function should be continuous and positive in its support. some commonly used weight functions are 14 • the cubic spline weight function: 1,0 1 2 1 , 3 4 44 3 4 2 1 ,44 3 2 32 32 (27) • the quadratic spline weight function: 1,0 1,3861 432 (28) with (29) where is the normalized distance between the node and point . the parameter for each node should be chosen large enough that matrix be invertible everywhere in the domain. also, it should be small enough to retain the local characteristic of the approximation. equation 29 directly applicable in a circular domain as in the following equation: • two dimensions, circular domain (30) in elliptic weight functions, each node has a major radius of influence , a minor radius of influence and an angle θ that determines the direction of the maximum radius of the influence ellipse. the influence elliptic domain of a node is determined by three parameters in contrast to one in the circular domain weights. the availability of more controlling parameters for determination of the influence domain of each node helps to increase computational efficiency of efgm. the normalized distance in the elliptic form (2d) is 22 (31) the use of the circular support may add the number of points in the influence domain of a node ineffectively. in the figure 2, the influence domain or support of a node that is at the center of the ellipse or circle is shown. there are more sample points such as integration points in the circular support than the elliptic support. 15 the derivatives of the weight functions can be computed using the chain rule. for example, for circular supports: 2 (32) the performance of elliptic domain is studied for timoshenko beam (figure 3). the problem is solved for =1000 as a parabolic tangential stress at the free end, = 3 0 × 107, and = 0 3. the beam is considered to be of unit depth and it is in plane stress state. this problem was numerically solved by [4, 15, 20]. the regular node distribution together with the background mesh that is used for numerical integration of the weak form is shown in figure 4. in each integration cell, 4 × 4 gauss quadrature is used. a linear basis and cubic spline weight function are used in the mls approximation. for this problem, circular nodal support of radius 3.5 times from longer nodal spacing is employed ( 5.3 ). also, elliptical nodal support of radius 3.5 times from longer nodal spacing ( 5.3 ), and smaller nodal spacing ( 5.3 ), in x and y direction respectively are employed. in table 1, the vertical displacement at the point ( 0) calculated by efg is compared with the exact solution. this table shows excellent agreement between efg and the analytical solution, particularly in the results of the elliptic domain. for more clarification, the deflection of the beam is shown in figure 5. also, the stresses at the center of the beam (x = l/2, y [−d/2,d/2]) compared with the exact solution are shown in figure 6. in addition, the distribution of the stresses in the beam is plotted in figure 7. it is of particular interest that very smooth stresses are obtained by using the elliptic domain-efgm without any additional treatment as is necessary in fem. furthermore, reduction of computational cost is verified. the ratio of the elapsed time for solving the problem with elliptic domain to the circular domain is approximately equal to 0.61 at 1800 field nodes. this is due to less value of in equation 8 when the elliptic domain is used. this example involves cracked plate under remote tension (figure 8). consider an infinite plate in stretching with crack at the center. due to the symmetry, twofold symmetry (abcd) is used as a model for this problem. along abcd the closed form solution in terms of polar coordinates in a reference frame , centered at the crack tip is 2 cos22 2 cos 2 12 , 2 (33) 2 cos22 2 sin 2 12 , 2 (34) where is the stress intensity factor, is poisson’s ratio and is young’s modulus. the square of 10mm×10mm, =100 mm; = 103 n/mm2, = 0 3 and remote stress of unit n/mm2. enriched efgm is used to solve this example where the re-mesh (redistribute of nodes in the crack tip region) is not needed. geometry of the crack is created as a line as shown in figure 9 by using the level set method [20]. additionally, same figure shows the detection of the enriched method for the nodes with the elliptic domains set. more information about the enriched meshless method is found in [9]. after the solution, the error of the displacement norm by using the circular 16 and the elliptic domain is extracted. table 2 is cleared that the results by using elliptic support is better than using circle support. anyway, major advantages of the use elliptic support in the cracked plate problem can be demonstrated in the following points: the error of the displacement norm is curtailed, and it is decreased rapidly when the nodes increase or when the area of the elliptic decrease. this gives the problem multi other parameters to control on the numerical solution. reduction of computational cost is occurred. this is due to less value of the nodes in the local domain (support). the reach path to the final solution is done under a small total number of nodes. this can be illustrated by figure 10-12 that done at same longer domain size. figure 10 represents the exact distribution of stress σyy, that is more coincide with figure 11, which represents the distribution of numerical stress σyy using the elliptic domain. it is a very clear the failure of the distribution of numerical stress using the circle domain for the exact distribution, as in figure12. elliptic domain of influence is used in the element free galerkin method to study the possibility of using this local domain in the computational mechanics. this domain changes the behavior of work of the used weight function in the extract the data from the nodes, because in the elliptic support, each node has three characteristic indications that are major radius, inner radius, and the direction of major local domain . furthermore, the space that is covered by the elliptic domain is less than the area of the circle domain at the same main diameter, and this reduces the computational time of the required calculation. also, the smooth final solution is done under a small total number of nodes reverse as happens in traditional domain. thus, using this domain, influence domain of a node is determined by three parameters in contrast to one in the other domains. the availability of more controlling parameters for determination of the influence domain of each node helps to increase computational efficiency of efgm. this paper can be extended by changing the direction of major local domain in the calculation, as well as in the use of the domain in the other advanced applications. 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[15] g.r. liu., "meshfree methods-moving beyond the finite element method", book, taylor and francis group, llc, (2010) [16] y. krongauz, and t. belytschko, "enforcement of essential boundary conditions in meshless approximations using finite elements", comput. methods appl. mech. eng., 131(1–2) (1996) 133–145. [17] g. r. liu, m. b liu, and k. y. lam, , "a general approach for constructing smoothing functions for meshfree methods", presented at ninth international conference on computing in civil and building engineering, taipei, china, april 3–5, (2002) 431–436. [18] g.r. liu, "an introduction to the programming of meshfree methods", book, springer, (2005) [19] b. n. rao, and a. s. balu., "fuzzy meshfree method for fracture analysis of cracks"، asme pressure vessels and piping division conference, (2007) pvp2007-26792. [20] v. p. nguyena, t. rabczuk, s. bordas, and m. duflot, "meshless methods: a review and computer implementation aspects", math. and comp. in simulation 79 (2008) 763–813. 18 : comparsion of vertical displacement end of beam uy efgm error % nodes uy exact elliptic domain circular domain elliptic domain circular domain 7 x 5 -0.00890 -0.00848 -0.00831 -4.71 -6.26 11 x 5 -0.00890 -0.00877 -0.00868 -1.46 -2.47 15 x 9 -0.00890 -0.00881 -0.00879 -1.01 -1.23 20 x 9 -0.00890 -0.00881 -0.00879 -1.00 -1.23 30 x 15 -0.00890 -0.00883 -0.00882 -0.78 -0.89 60 x 30 -0.00890 -0.00890 -0.00884 0.00 -0.67 : the error of the displacement norm results nodes circular domain size disp. norm error elliptic domain size disp. norm error 2.5 x 2.25 0.372 2.5 x 2.00 0.3625 x 5 2.5 0.372 2.5 x 1.50 0.202 2.5 x 2.25 0.103 2.5 x 2.00 0.1027 x 7 2.5 0.115 2.5 x 1.50 0.075 2.5 x 2.25 0.073 2.5 x 2.00 0.04310 x 10 2.5 0.081 2.5 x 1.50 0.028 19 discretization using meshless methods nodes, circular domains of influence. requirement representation of elliptic domain, and circular domain to the integrations points. 20 the timoshenko beam. 20 x 9 regular nodes distribution with background mesh configuration for the timoshenko beam. deflection representation of the beam. 21 stress comparison, shear stress. stress comparison, normal stress. 22 stress distribution, shear stress σxy. stress distribution, normal stress σxx. 23 infinite cracked plate under remote tension. creation and detection of abcd crack. 24 exact stress distribution (deformed scaled). numerical (elliptic domain used) stress distribution (deformed scaled). 25 numerical (circle domain used) stress distribution (deformed scaled). ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٩ تأثير التقوية باأللياف على الموصلية الحرارية والخواص الميكانيكية للراتنجات المتصلبة بالحرارة علي جاهل سلمان. م .م بابل–المعهد التقني الخالصة -٠°( بشكل ظفائر محاكة ثنائية اإلتجـاه ن الكاربو ليافأإن الهدف من هذا البحث هو دراسة تأثير التقوية ب بعد تقويته البولي أستر غير المشبع راتنج لالموصلية الحرارية على (1.75g\cm3)ذات كثافة سطحية ) ٩٠° إستُخدمت معادلة فورير لحساب التغير فـي حيث (20% ,40% ,60%) هذه األليافبنسب وزنية مختلفة من لهـذا الخواص الميكانيكية إضافة إلى ذلك فقد تم حساب التغير في قيم . (k)قيمة معامل التوصيل الحراري وقد شملت هذه الخواص كل من مقاومة الصدمة ، مقاومة الـشد المذكورة أعاله وزنية النسب ال بنفسراتنج ال خـواص لقد أظهرت النتائج تحسن الموصلية الحرارية وال. ، والصالدة ، مقاومة اإلنضغاط ، مقاومة اإلنثناء .الميكانيكية بعد التقوية باأللياف ، وترتفع القيمة الخواص المذكورة بزيادة نسبة التقوية . ، الخواص الميكانيكية ،الموصلية الحرارية ، ألياف الكاربون راتنج البولي أستر غير المشبع: الكلمات الدالة effect of reinforcing by fibers on thermal conductivity and mechanical properties of thermosetting resins ali j. salaman technical institute-babylon assist. lecturer abstract . the objective of this research is to study the effect of reinforcement by carbon fibers as woven roving )°٠°-٩٠( with density (1.75g\cm3)on thermal conductivity for unsaturated polyester resin after reinforcing it by different percentage of fibers (20%, 40%,60%) and we used fourier equation to calculate the thermal conductivity coefficient (k) . also the mechanical properties of this resin was calculated with the same reinforcing percentage of fibers and these properties included : impact strength , tensile strength , compression strength , flexural strength , and hardness . the results show that improvement in thermal and mechanical properties after reinforced by fibers , and these properties will rise as increased in reinforcement percentage . ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٠ .)introduction(المقدمة عرفتْ تقنية تصنيع المواد المتراكبة بأبسط صورها منذ قرون عدة حيث إستخدمها البابليون في بناء بيوتهم تتكون المادة المتراكبة من دمج مادتين أو أكثر وتشمل . ريق خلط نشارة الخشب بمادة الطين لتقويته عن ط إن عملية . يةئ مختلفتي الخواص الميكانيكية والفيزيا)reinforced plastic( والبالستك (blends)الخالئط تختلف عن خواص المواد الدمج هذه تؤدي إلى الحصول على مادة جديدة ذات خواص هندسية وفيزيائية يعتمد اإلستخدام العام للمادة المتراكبة بشكل كبير على الخواص الميكانيكية والفيزيائية .الداخلة في تركيبها لهذه المواد لذلك فإن دراسة هذه الخواص تحت تأثير القوى واألحمال في ظروف مختلفة يكتسب أهمية كبيرة يوجد في الطبيعة الكثير من األمثلة على المواد .]١[ن عمل هذه المواد لمعرفة مدى مالئمة هذه الخواص لمكا أما في الصناعة فإن تقوية الراتنجات باأللياف الصناعية . الخشب المتراكبة ومنها ألياف السليلوز مع مادة :و لتصنيع مادة متراكبة يجب توفر مادتين هما . هي األكثر إنتشاراً .(matrix material)المادة األساس -١ تكون مواد األساس أما مواد معدنية متكونة من المعادن وسبائكها وتتميز بثقل وزنها ومتانتها العالية أو قد والتي تمتاز بخفة وزنها ومقاومتها المرتفعة لدرجات الحرارة العالية ولكنها ضعيفة تكون مواد سيراميكية وهي األكثر إستعماالً وإنتشاراً ِلما تتميز به ة األساس مواد بوليميريةكذلك تكون الماد. المقاومة لقوى الصدم راتنج اإليبوكسي و الفينول من خواص ميكانيكية وحرارية جيدة ، ومن األمثلة على المواد البوليمرية .]٢[والبولي أستر . (reinforcing material) مادة التقوية -٢ في هكذا مواد وهي المقاومة العالية والمطيلية المنخفضة حتى تستطيع تقوية يجب توفر ميزتين أساسيتين والتي تكون بقطر أكبر من particulate) (هناك عدة طرق للتقوية منها التقوية بالدقائق. األساس المواد (1 µm)كذلك تتم التقوية بالتشتت ، (dispersed)ويكون قطر الدقائق أقل من (0.1µm ) .أساليب أما أكثر مقارنة بالمواد الراتنجية ، خواصنظراً لما تتميز به من fibers)(التقوية شيوعاً فهي التقوية باأللياف .]٢[وتكون األلياف بأنواع وأشكال مختلفة فمنها ما يكون بشكل مستمر أو مقَطع أو بشكل ظفائر محاكة ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩١ .)fibers reinforcing(التقوية باأللياف لرئيسي من التقوية باأللياف هو لتحسين الخواص الميكانيكية والفيزيائية للراتنجات حيـث تـزداد إن الهدف ا مقاومة الشد والصدمة والصالدة بشكل كبير مما يسمح بإستخدام هذه المواد المقواة فـي مجـاالت صـناعية لك لتفريقها عن المـواد وذ (advanced composites) المواد المتراكبة بالمتقدمة هيطلق على هذ. عنيفة إن األلياف في هذا النوع من المواد المتراكبـة هـي المـسؤول ) .filled polymers ( البوليمريةالمحشوة الرئيسي عن تحمل األحمال الخارجية ، ومن أكثر أنواع األلياف شيوعاً في مجال المواد المتراكبة المتقدمـة .]٣[الزجاج و كيفالر وهي ألياف الكاربون .)polyester resin(اتنج البولي أستر ر ويتم thermosetting resins) (يعتبر راتنج البولي أستر أحد أنواع الراتنجات المتصلدة بالحرارة مع حامض غير مشبع ثنائي القاعدة monomer ( glycol(تحضيره من تفاعل مونومير الجليكول )dibasic acid (وميرين أو كليهما على رابطة مضاعفة في تركيبه،وبعد تكون ويشترط أن يمتلك أحد المون باإلضافة إلى عامل مساعد يتكسر styrene)(البوليمر الخطي يمزج مع مونومير فنيل فعال مثل الستايرين إلى شقوق حرة وبهذا تتم بلمرة مونومير الفنيل مع الروابط المزدوجة على طول سلسلة البوليمر وبذلك بالنسبة ( حرارية جيدة إذ يتحمل الحرارة العاليةصيمتلك راتنج البولي أستر خوا. تريتكون البولي أس عند درجة spontaneous decomposition)(اً تلقائياً ك ولكنه يعاني تفك260ºc)(ولغاية) للراتنجات وكذلك يمتاز بمقاومة كهربائية ممتازة ومقاومة. حتى بعدم وجود األوكسجين ) 300ºc(حرارة تقارب لكونه قليل الكلفة ولكنه ةكيمياوية للمذيبات واألحماض واألمالح ومقاوم للبلى والتأثيرات البيئية ،باإلضاف ويضاف البولي أستر إلى األلياف الزجاجية لصناعة هياكل القوالب ومكونات . يتصف بالضعف والهشاشة . ]٤[أجسام الطائرات والسيارات وغيرها من الصناعات .)carbon fibers (كاربون ألياف ال الخمولية حيث تمتلك مقاومة عالية ضـد الرطوبـة وألغلـب :تمتلك ألياف الكاربون العديد من المزايا منها المواد الكيميائية الشائعة ، موصلية كهربائية وحرارية عالية على طول محـور األليـاف ، وثبـات األبعـاد جميع أنواع ألياف الكاربون من الكسر الهش تحت تأثير اإلجهاد تعاني. وإنخفاض التمدد الحراري المحوري تتضمن ألياف الكاربون بلورات صغيرة مـن مـادة . وهذا متوقع نظراً إلرتفاع مقاومتها وإنخفاض مطيليتها (turbostratic graphite) يوضـح ) ١(الجـدول رقـم . ]٥[ والتي هي أحد األشكال المتآصلة للكـاربون .(ºc 20)اربون عند خواص ألياف الك ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٢ .)thermal conductivity (الموِصلية الحرارية عند وجود فرق حراري بين سطحين سوف تنتقل الحرارة من السطح ذو درجة الحرارة األعلى إلى السطح وعلى هذا األساس يمكن تعريف . ذو درجة الحرارة الواطئة ، وتُعرف هذه الظاهرة بالموِصلية الحرارية موِصلية الحرارية على إنها معدل إنسياب الحرارة عبر وحدة المساحة خالل وحدة الزمن عند وجود إنحدار ال تختلف آلية التوصيل الحراري بإختالف حاالت المادة. ]1[ حراري بين سطحين مقداره درجة مئوية واحدة تعتمد . ة أم موصلة للحرارة والذي من خالله تصنف المادة على إنها عازل) صلبة ، سائلة ، غازية ( الموصلية الحرارية في المواد المعدنية على إنتقال اإللكترونات الحرة ، أما في المواد المتراكبة فيعتمد حيث تبدي المواد المتراكبة موصلية قوية fibers orientation)(التوصيل الحراري على توجيه األلياف . through the thickness)(وِصلية أضعف بإتجاه السمك ومin-plane)(باإلتجاه الطولي لأللياف الموصلية الحرارية للراتنجات بعد التقوية باأللياف وهذه الزيادة متوقعة نظراً لقابلية األلياف بشكل عام تزداد . ]٣[) الراتنج(للتوصيل الحراري مقارنة بالمادة األساس ككل .)terials propertiescomposite ma (خواص المواد المتراكبة تعتمد اإلستخدامات العامة والهندسية للمواد المتراكبة إلى حد بعيد على خواصها الميكانيكية والفيزيائية مثـل مقاومة الشد والمرونة وقابلية المادة لإلستطالة ومقاومتها للحرارة والظروف البيئية مثـل الرطوبـة وأشـعة إن جميع هذه الخواص تعتمد كثيراً على التركيب الجزيئـي . اُألخرى الشمس وغيرها من الخواص التطبيقية كما تعتمد هذه الخواص إلى حد كبير على مواد التقويـة . للراتنج وعلى وزنه الجزيئي وعلى القوى الجزيئية :ومن الخواص المناقشة في هذا البحث ما يأتي . ]١[وعلى المواد المضافة مثل الحشوات والملدنات . (impact strength) الصدمة مقاومة -١ تُعبر مقاومة الصدمة عن قدرة المادة لمقاومة الكسر تحت تأثير حمل مفاجئ ، كما تعتبر مقياساً لمتانة المـادة .]٧[. حيث المواد األكثر متانة هي التي تبدي أعلى مقاومة للصدمة .( tensile strength) مقاومة الشد -٢ تتكـون . الشد مقياساً لقابلية المادة على مقاومة القوى الساكنة التي تحاول سحب المادة وكسرها تعتبر مقاومة .]٥[. المواد المتراكبة الليفية من ألياف قوية هشة مغمورة في المادة األساس التي تتصف بكونها أكثر مطيلية .(compressive strength) مقاومة اإلنضغاط -٣ دى تحمل المادة عند تعرضها إلى حمل إنضغاط ساكن قبل أن تنكـسر ، وتقـاس عـادة تبين هذه المقاومة م . والقيم العالية تُشير إلى كبر قوى التماسك بين جزيئات المادة (mpa)بوحدات ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٣ . ( flexural strength)مقاومة اإلنثناء -٤ عرفها على إنها أقصى حمل ساكن يمكن تسليطه على وتعتبر هذه الخاصية مقياساً لمقاومة اإلنحناء ، ويمكن ت .]٦[ . (mpa)نموذج اإلختبار قبل أن يخضع أو ينكسر وتقاس بوحدات .(hardness) الصالدة -٥ تُعرف الصالدة على إنها مقاومة المادة للخدش أو اإلختراق ، وهنالك ِعدة مقاييس عالميـة مختلفـة لتعيـين يحدث اإلختراق بمعدل بطـيء فـي . اد اللدائنية وأكثرها شيوعاً صالدة برينل وصالدة روكويل صالدة المو سطح النموذج أثناء تسليط القوة ألجل اإلختبار مما يؤدي إلى حدوث زحف موضـعي ، وبعـد زوال القـوة مد في حساب صـالدة المؤثرة تحصل إستعادة بطيئة نسبياً في اإلختبار مما يؤدي إلى تغيير أبعاد األثر المعت .]٦[المادة ولمنع حدوث ذلك يتوجب اإللتزام بالفترة الزمنية المحددة لتسليط القوة على سطح النموذج . )experimental work(الجزء العملي يتضمن الجزء العملي إعداد المواد األولية وكيفية تحضير المادة المركبة إضافة إلى اإلختبارات الميكانيكيـة .ي تم إجراءها على المادة المتراكبة الت . المواد المستخدمة في البحث -أوالً :تم في هذا البحث إستخدام المواد التالية والتي تم تصنيع النماذج منها وهي .(unsaturated polyester resin) راتنج البولي أستر غير المشبع -١ الـشكل رقـم ي في ئ والموضح تركيبه الكيميا( palatel a420 )ستر غير المشبع أج البولي تنستخدام راإتم .(basf aktiengesellschaft)هذا الراتنج مجهز من شركة .)١( .(carbon fibers) ألياف الكاربون -2 فـي iiالنوع رقم ( (1.75g/cm3)ذات كثافة سطحية ) ٩٠°-٠°(ثنائية اإلتجاه تم إستخدام ألياف الكاربون .(hyfil ltd .,uk) من شركة ةمجهزألياف الكاربون )). ٢(الجدول رقم . (test specimens preparation) تحضير النماذج -ثانياُ :وتشمل اآلتي ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٤ . تحضير نماذج إختبار الموصلية الحرارية -١ إلـى يتم إضافة المـادة المعجلـة : وهي تحضر كاآلتي (3mm) وسمك (25mm)تكون هذه العينات بقطر والتي تحتوي علـى ) cobalt octoatel( غير المشبع وتخلط جيداً معه تسمى هذه المادة أسترولي ب الراتنج توضـع كميـة مـن . )٢(% بنسبة )mekpo(ة د المادة المصل إليهبعدها تضاف ) %6( فعال بنسبة تكوبال مـن األولـى طبقـة الراتنج على سطح القالب الداخلي وتنشر بفرشاة لضمان توزيعه بانتظام بعدها توضع ال .ج عليها وهكذا لبقية الطبقات لتتكون مادة متراكبة بالسمك المطلـوب تن من الرا أخرى ثم نضع كمية األلياف تم إستخدام الطريقة الوزنية في حساب كمية كل من األلياف والراتنج المستخدمة حيث كانت نـسبة األليـاف ـ رك لتتصلب ، بعدها تهذه النماذج وت كبسعدها ت في تصنيع المادة المتراكبة ،ب(20% ,40% ,60%)هي تم ي .مال التصلبإلك) 75ºc( في الفرن في فرن درجة حرارته هاإخراجها من القالب ووضع . نماذج اإلختبارات الميكانيكية -٢ :وتشمل كل من .(impact specimens) نماذج إختبار الصدمة -١ والمالئمة للفحـص فـي جهـاز (astm-e23)صفات القياسية تم تصنيع نماذج إختبار الصدمة حسب الموا ونـصف قطـر قاعـدة (mm 0.5)عمق الحز فـي النمـاذج . (charpy impact)الصدمة نوع شاربي ُأستخدم جهاز فحـص مقاومـة الـصدمة نـوع شـاربي ) . º٤٥( وبزاوية حز مقدارها (mm 0.25)الحز (charpy impact instrument) ف على مدى مقاومة المادة المتراكبة لِحمل الصدم للتعر . .(tensile specimens)نماذج إختبار مقاومة الشد -٢ رُأسـتخدم هـذا اإلختبـا . في تصنيع نماذج إختبار مقاومة الشد(iso-r-527)تم إعتماد المواصفة القياسية ، حيـث تـم إسـتخدام جهـاز لمعرفة خواص المادة المتراكبة تحت تأثير ِحمل شد محوري بإتجاه واحد ألماني المنشأ في قيـاس هـذه الخاصـية وبمعـدل ِحمـل (universal instrument)اإلختبارات العام (20 kn). . (compression specimens)نماذج إختبار مقاومة اإلنضغاط -٣ . وهي بشكل منشور رباعي (astm-d618)ةتم تصنيع نماذج إختبار مقاومة اإلنضغاط حسب المواصف .( flexural strength specimens) نماذج إختبار مقاومة اإلنثناء -٤ ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٥       ∆ ∆ ××−= x t akq ( )xt∆∆ في تصنيع نماذج اإلختبار والتي كانـت علـى شـكل نمـاذج (astm d790)ُأعتمدت المواصفة القياسية .(10mm×135mm)مستطيلة بأبعاد اإلنثناء بطريقة اإلختبار ثالثي النقاط ويـتم ذلـك بإسـتخدام مكـبس ومة اإلنضغاط ومقا يمكن قياس مقاومة .هيدروليكي متعدد األغراض لقياس أقصى حمل مسلط على منتصف نموذج اإلختبار . (hardness specimens) نماذج إختبار الصالدة -٣ تـم . (mm 10) وسـمك (mm 25)تم تصنيع نماذج إختبار الصالدة على شكل أقراص دائريـة بقطـر لحساب صالدة المادة المتراكبة ، حيث ُأستخدمت كرة فوالذية (brinell hardness)إستخدام طريقة برينل وبعد زوال القوة المؤثرة يتم قيـاس قُطـر (sec 15) لمدة (kg 10) مع تسليط ِحمل مقداره (mm 5)بقطر .األثر الناتج على السطح . وصلية الحرارية قياس الم-ثالثاً وينص هذا ) (k في حساب معامل الموصلية الحرارية (fourier law) ستخدام قانون فورير إيمكن : القانون على ( w )كمية الحرارة المارة بوحدة الزمن وتقاس بوحدات = q: حيث k = معامل الموصلية الحرارية ويقاس بوحدات( w/m.ºc ) a = سياب الحرارة وتقاس بوحداتنإمساحة مقطع (m2) ( ºc/m )التدرج الحراري نسبة للمسافة ويقاس بوحدات = والمصنع من قبل (heat conduction unit) لية الحراريةوِص يوضح جهاز قياس الم( 2 )الشكل رقم . (p.a.hilton ltd england)شركة .)s and discussionresult(النتائج والمناقشة من خالل هذه اإلختبارات التي ُأجريت على المادة المتراكبة المتقدمة والمكونة من راتنج البولي أسـتر غيـر تم الحصول على النتائج الموضحة في المخططات ) ٩٠°-٠°(المشبع المقوى بألياف الكاربون ثنائية اإلتجاه .ية والموصلية الحرارية نسبة إلى مقدار التقوية باأللياف البيانية والتي تُمثل قيم الخواص الميكانيك ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٦ . نتائج اإلختبارات الميكانيكية -١ يوضح قيم مقاومة الصدمة مع نسبة التقوية باأللياف ، حيـث تعتبـر )٣(الشكل رقم . مقاومة الصدمة -١ باأللياف تزداد قيمة مقاومـة مقاومة الصدمة بشكل عام منخفضة للراتنجات نظراً لهشاشتها ولكن بعد تقويتها الصدمة ويرجع السبب في ذلك إلى كون األلياف سوف تتحمل الجزء األكبر من طاقة الصدم المسلطة علـى وهكذا تزداد مقاومة الصدمة مع زيادة نـسبة التقويـة باألليـاف . المادة المتراكبة مما يحسن هذه المقاومة .]8[%) ٦٠(و %) ٤٠(إلى تعتبر الراتنجات من المواد الهشة حيث مقاومتها للشد منخفضة جداً وهذا مـا نـراه فـي . مقاومة الشد -٢ ، ولكن عند إضافة األلياف إلى هذه المواد تتحسن مقاومتها للشد بـصورة كبيـرة حيـث إن )٤(الشكل رقم لـك ألن األليـاف الجزء األعظم من الجهد المسلط تتحمله األلياف مما يرفع مقاومة الشد للمادة المتراكبة وذ وتزداد مقاومة الشد بزيادة نسبة األلياف المضافة حيث تشِغل األلياف حيز أكبـر . تتميز بمطيليتها المنخفضة .]٩[داخل الراتنج مما يسمح بتوزيع الِحمل المسلط عليها بشكل أفضل مقاومة اإلنـضغاط للمـادة إن تقوية المواد الراتنجية باأللياف يؤدي إلى إرتفاع قيم . مقاومة اإلنضغاط -٣ الذي يمثل إختبار مقاومة اإلنـضغاط )٥(الشكل رقم المتراكبة الناتجة من هذا التقوية وهذا واضح من خالل راتنج البولي أستر غير المشبع المقوى بألياف الكاربون ، حيث مقاومة اإلنضغاط ترتفع بـشكل حـاد عنـد ل مل على األلياف وكذلك كفاءة الربط بين المادة األسـاس وأليـاف التسليح بألياف الكاربون نظراً لتوزيع الحِ وتزداد مقاومة المادة المتراكبة لإلنضغاط مع زيادة نسبة األليـاف . التقوية مما ويرفع قيم مقاومة اإلنضغاط .]١٠[المضافة لنفس السبب المذكور أعاله ومـن اء منخفضة وهذا راجع إلى هشاشة هذه الموادتمتلك المواد البوليمرية مقاومة إنثن . مقاومة اإلنثناء -٤ الذي يمثل إختبار مقاومـة اإلنثنـاء )٦(الشكل رقم وكما موضح في ضمنها راتنج البولي أستر غير المشبع حيث تكون قيمة مقاومـة اإلنثنـاء منخفـضة قبـل راتنج البولي أستر غير المشبع المقوى بألياف الكاربون ل ويعود السبب في الكاربونه بألياف تن هذه المقاومة تبدأ باإلرتفاع لهذا الراتنج بعد تقوي التقوية باأللياف ، ولك ذلك إلى إرتفاع معامل مرونة هذه األلياف مما يؤدي إلى تحملها إلى الجزء األكبر من الحمل المـسلط علـى ـ دعالمادة المتراكبة مما يؤدي بدوره إلى زيادة مقاومة اإلنثناء لهذه المادة الم وتـزداد هـذه . ة باألليـاف م . ]١٠[المقاومة مع زيادة نسبة التقوية باأللياف تـدني )7(الشكل رقـم تتميز المواد اللدائنية بشكل عام بإنخفاض صالدتها حيث نالحظ من . الصالدة -٥ كل حاد عند قبل التقوية باأللياف ، إال إن قيمة الصالدة ترتفع بش البولي أستر غير المشبع قيمة صالدة راتنج نظراً لتوزيع الِحمل على األلياف مما يقلل معدل اإلختراق لسطح المـادة المتراكبـة الكاربونالتسليح بألياف ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٧ وتزداد صالدة المادة المتراكبة مع زيادة نسبة األلياف المضافة لنفس السبب المذكور . صالدتها ويرفع قيم .]٩[أعاله . ية نتائج إختبار الموصلية الحرار-٢ من خالل النتائج التي تم الحصول عليها من جهاز الموصلية الحرارية والتي تم تطبيقها في معادلة فورير من راتنج البولي أستر غير ل نالحظ إن الموصلية الحرارية (k)أجل حساب قيمة معامل الموصلية الحرارية نتيجة لإلهتزازات الهيكلية في بنيته ارةتزداد مع إرتفاع درجة الحرالمشبع قبل تقويته بألياف الكاربون الداخلية حيث كلما إرتفعت درجة الحرارة زادت اإلهتزازات الهيكلية مما يسبب موصلية أكثر للحرارة وهذا راتنج البولي أستر غير المشبع ، حيث تبدأ ل والذي يمثل الموصلية الحرارية)٨(الشكل رقم ما نالحظه في يادة درجة الحرارة ويرجع السبب في ذلك كما ذكرنا إلى اإلهتزازات في الهيكل الموصلية باإلرتفاع مع ز .[10]الداخلي للراتنج التي تزداد بإرتفاع درجة الحرارة والذي يمثل )٩(الشكل رقم وكما موضح في بعد التقوية باأللياف راتنجلل وتزداد قيمة الموصلية الحرارية إن هذه الزيادة في . ألياف %) ٢٠(راتنج و %) ٨٠(ة المكونة من الموصلية الحرارية للمادة المتراكب وعند زيادة نسبة التقوية . هي موصل جيد للحرارة الكاربونالموصلية الحرارية راجعة إلى كون ألياف الذي يمثل )١٠(الشكل رقم وكما موضح في %) ٦٠(وإنخفاض نسبة الراتنج إلى %) ٤٠(باأللياف إلى ألياف حيث تزداد الموصلية %) ٤٠(راتنج و %) ٦٠(ة للمادة المتراكبة المكونة من الموصلية الحراري وهذه الزيادة في الموصلية متوقعة نظراً لقدرة األلياف على التوصيل الحراري الحرارية للمادة المتراكبة ، .[11] الراتنجية مقارنة بالمادة )١١(الشكل رقم وكما هو مدرج في %) ٦٠(اف إلىوتزداد هذه الموصلية الحرارية عند زيادة نسبة األلي ألياف والسبب في %) ٦٠(راتنج و %) ٤٠(والذي يمثل الموصلية الحرارية للمادة المتراكبة المكونة من هذه الزيادة هو وجود نسبة كبيرة من األلياف داخل المادة المتراكبة والتي تعتبر موصل جيد للحرارة كما . يوضح مقارنة بين الحاالت األربعة للتقوية )١٢(كل رقم الش. ]12[ذكرنا سابقاً .)conclusions (اإلستنتاجات : التالية باالستنتاجاتمن خالل النتائج التي تم الحصول عليها يمكن الخروج .كونه من المواد الهشة راتنج البولي أستر غير المشبع إنخفاض قيم الخواص الميكانيكية ل-١ .راتنج البولي أستر غير المشبع بعد تقويته بألياف الكاربون قيم هذه الخواص الميكانيكية ل تحسن -٢ ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٨ . تزداد قيم الخواص الميكانيكية مع زيادة نسبة ألياف الكاربون المضافة بسبب المقاومة العالية لأللياف-٣ . الكاربون ألياف بعد تقويته براتنج البولي أستر غير المشبع ل تحسن الموصلية الحرارية -٤ كبة مع زيادة درجة الحرارة والسبب يرجع إلى التقوية بألياف ارت زيادة الموصلية الحرارية للمادة الم-٥ . والتي تعتبر موصل جيدة للحرارة مقارنة بالمادة األساس الكاربون .)references( المصادر 1moslem,ali ibrahim “ study using of antimony trioxide material as a flame retardant material ”, msc thesis , babylon university , iraq , 2003 . 2p. vincenzini and m. singh “advanced inorganic fibrous composites v ” , transtech publications, 2006 . 3p.k. mallick “fiber-reinforced composites: materials, manufacturing, and design”, 3rd edition , crc press, 2007. 4efunda engineering fundamentals “ polymer material properties ” ,(2001) . 5e.p.degarmo, j.t. black, and r.a. kohser “ materials and processes in manufacturing ” , 10th edition , john wiley & sons , 2008 . 6liyong tong ,adrian p.mouritz ,michael k.bannister “3d fiber reinforced polymer composites” , first edition , elsevier science ltd , 2002 . 7b.a.azhdar “impact fracture toughness of fiber reinforced epoxy resin” ,m.sc thesis ,u.o.t ,iraq , 1992 . 8g.dorey ,g.r.sidey and j.hutchings “impact properties of carbon fiber/ kevlar 49 fiber hybrid composites” , composites 9 (january 1978) pp.25-32. 9-ali i.al-mosawi “study of some mechanical properties for polymeric composite material reinforced by fibers ” , al-qadessiyah journal for engineering science , vol 2 , no 1 , 2009 . pp.14 – 24 . 10dr. abbas a. al-jeebory, ali i.al-mosawi, sajed a. abdul allah “effect of percentage of fibers reinforcement on thermal and mechanical properties for polymeric composite material ” , iraqi journal of mechanical and materials engineering , first conference of engineering college , 2009 . 11bogomolov v. and kartenko n. “thermal conductivity of the opalepoxy resin nanocomposite ” , physics of the solid state , vol 45,no 5,pp.957-960, 2003. 12f.rondeaux , ph. bredy and j.m.rey. “thermal conductivity measurements of epoxy systems at low temperature” , cryogenic engineering conference (cec), usa, july 16-20, 2001 . ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٩٩ اريةجهاز قياس الموصلية الحر) : ٢(الشكل رقم ]٥[ (ºc 20)خواص ألياف الكاربون عند ) : ١(الجدول رقم elongation to fracture , % tensile strength,gn/m2 young's modulus,gn/m2 density 103 kg/m3 diameter µm property 0.5 2.2 390 1.95 7-9.7 type i 1 2.7 250 1.75 7-8.7 type ii ]1[ي لراتنج البولي أستر غير المشبعئ التركيب الكيميا:)١(الشكل رقم n o n=3-6 ester groups hoc-c=c-c o-c-c-o-c --c-o-c-c-o-c-c=c-c--o-c-c-oh o o o o o ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ٢٠٠ إختبار مقاومة الشد ) : ٤(الشكل رقم reinforcing percentage (%) te n si le s tr en gt h ( n /m 2 ) إختبار مقاومة الصدمة ) :٣(الشكل رقم reinforcing percentage (%) im p ac t st re ng th ( k j/ m 2 ) 0 10 20 30 40 50 60 70 80 0 50 100 150 200 250 300 350 400 0 10 20 30 40 50 60 70 80 0 20 40 60 80 100 120 140 160 180 200 reinforcing percentage (%) c o m p re ss io n st re n gt h (m p a) إختبار مقاومة اإلنضغاط ) : ٥(الشكل رقم reinforcing percentage (%) fl ex u ra l s tr en gt h (g p a) إختبار مقاومة اإلنثناء :)٦(م الشكل رق 0 10 20 30 40 50 60 70 80 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0 10 20 30 40 50 60 70 80 0 20 40 60 80 100 120 140 160 180 200 ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ٢٠١ 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 90 100 reinforcing percentage (%) h ar d n es s (n /m 2 ) إختبار الصالدة :)٧(الشكل رقم ) ألياف% ٢٠+ راتنج % ٨٠ (:)٩(الشكل رقم temperature,(ºc) th er m al c o n d uc ti vi ty , k ( w /m . º c) ) ألياف% ٤٠+ راتنج % ٦٠ (:)١٠(الشكل رقم temperature,(ºc) th er m al c o n d uc ti vi ty , k ( w /m . º c) ) ألياف% ٦٠+ راتنج % ٤٠ (:)١١(الشكل رقم temperature,(ºc) th er m al c o n d uc ti vi ty , k ( w /m . º c) temperature,(ºc) th er m al c o n d uc ti vi ty , k ( w /m . º c) للراتنج الموصلية الحرارية :)٨(الشكل رقم 30 35 40 45 50 55 60 65 70 75 80 0.20 0.30 0.40 0.50 0.60 0.70 0.80 30 35 40 45 50 55 60 65 70 75 80 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 30 35 40 45 50 55 60 65 70 75 80 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 30 35 40 45 50 55 60 65 70 75 80 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 30 35 40 45 50 55 60 65 70 75 80 0.20 0.40 0.60 0.80 1.00 1.20 1.40 resin only 80% resin + 20% fibers 60% resin + 40% fibers 40% resin + 60% fibers مقارنة بين الحاالت األربعة :)١٢ (الشكل رقم temperature,(ºc) th er m al c o n d uc ti vi ty , k ( w /m . º c) top secret message using ebcdic in two cover al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 222 secret message encoded by ebcdic in multiple dct for two covers ahmed hassan hadi technical college of najaf abstract this paper suggest a proposed algorithm to hide message encoded using "ebcdic" in multiform dct's coefficients for two images. the dct has the property that, for a typical image, most of the visually significant information about the image is concentrated in just a few coefficients of the dct. notice that most of the energy is in the upper left corner. hiding message can be obtained without use original image with high quality. the experiments for embedding and extracting was successfully simulated by matlab. keywords: steganalysis, steganography, ebcdic, dct, data hiding ع مخفية فيالرسالة السرية المشفرة برمز التبادل العشري الثنائي الموس معامالت تحويلة الجيب تمام المميزة متعددة الشكل لغطاءين حمد حسن هاديأ الكلية التقنية / النجف وجزالم مخفيةة ااخةم ممةام " "ebcdicإلخفاء رسالة هامة مشفرة بشفرة خوارزمية اقتراحا البحث هذتم في ( للصةورة dctاة من تحويلةة الجيةب تمةام المميةزة تم االستفا للصورتين. (dct)تحويلة الجيب تمام المميزة وال (dct)المثاليةةة بةةال االةةب المملومةةا الرامةةة المرصيةةة رةةو الصةةورة مرعةةزة فةةي ب ةةمة مةةن ممةةام ا الرسالة المخفية يمكن ال تنتزع بدول استمما الصور األصلية . علماً ال االب الطاقة في الزاوية اليسرى المليا واسةةتخ ا الرسةةالة وتمةةج المحاعةةة باسةةتخدام بر ةةام إلخفةةاءالتجةةارت تمةةج بنجةةاح .نوعيةةةوبدقةةة عاليةةة ال matlab)). introduction data hiding is a method of hiding secret messages into a cover-media such that an unintended observer will not be aware of the existence of the hidden messages. steganography is the science that involves communicating secret data in an appropriate multimedia carrier, e.g., image, audio, and video files. it comes under the assumption that if the feature is visible, the point of attack is evident, thus the goal here is always to conceal the very existence of the embedded data. steganography has various useful applications. (cheddad, et al, 2010). in the literature, many techniques about data hiding have been proposed (bender, et al, 1996), (chen, et al,1998), (marvel, et al, 1999) and (chung, et al, 2001). one of the common techniques is based on manipulating the least-significant-bit (lsb) planes by directly replacing the lsbs of the cover-image with the message bits. lsb methods typically achieve high capacity. (wang, et al, 2000) proposed to embed secret messages in the moderately significant bit of the cover-image. a genetic algorithm is developed to find an optimal substitution matrix for the embedding of the secret messages. they also proposed to use a local pixel adjustment process (lpap) to improve the image quality of the stego-image. ahmed hassan hadi 222 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 (matsui, et al, 1994) embedded information in dithered images by manipulating the dithering patterns and in fax images by manipulating the run-lengths. (maxemchuk, et al, 1997) changed line spacing and character spacing to embed information in textual images for bulk electronic publications. these approaches cannot be easily extended to other binary images and the amount of data that can be hidden is limited. (bhattacharjya, et al, 1999) marking a binary document is proposed by treating a binary image as a grayscale one and manipulating the luminance of dark pixels slightly so that the change is imperceptible to human eyes yet detectable by scanners. (zhang x., 2011) proposes a novel reversible data hiding scheme for encrypted image. after encrypting the entire data of an uncompressed image by a stream cipher, the additional data can be embedded into the image by modifying a small proportion of encrypted data. according to the datahiding key, with the aid of spatial correlation in natural image, the embedded data can be successfully extracted and the original image can be perfectly recovered. (pavan, et al, 2005) proposed a hybrid image registration algorithm to identify the spatial or intensity variations between two color images. the proposed approach extracts salient descriptors from the two images using a multivariate entropy-based detector. the transformation parameters are obtained after establishing the correspondence between the salient descriptors of the two images. (pang, et al, 2004) introduced stegfd, a steganographic file driver that securely hides user-selected files in a file system so that, without the corresponding access keys, an attacker would not be able to deduce their existence. they proposed two schemes for implementing steganographic b-trees within a steg fd volume. in this paper, 8-bit grayscale images are selected as the cover media. these images are called coverimages. cover-images with the secret messages embedded in them are called stego-images. for data hiding methods, the image quality refers to the quality of the stego-images. the extended binary-coded decimal interchange code the extended binary-coded decimal interchange code (ebcdic) contains 8 bits with no parity. the ebcdic code is given in table 1. it is used extensively in ibm computer systems. let the secret message is " jackdaws love my big sphinx of quartz". and encode it by ebcdic that is illustrated in table 2. the algorithm the algorithm can be divided into two sections: insertion algorithm and detection algorithm insertion algorithm figure 1 represent the insertion algorithm as 1. encode the message using ebcdic for each letter. 2. read two images: internal image with size (64×64) pixels, and external image with size(512×512) pixels. 3. take ( 32 × 32) discrete cosine transform to hide message with unrecognizable effect of the internal cover image with size (64×64) pixels. 4. take ( 2 × 2) discrete cosine transform to make high quality of the external cover image size (512×512) pixels. 5. distribute each bit of ebcdic message into coefficients of dct for internal image ( multiply "1 or 0 " according to bit by each last (4×4) coefficients). 6. distribute dct for internal image into dct for external image by replace each last (8×8) coefficients. 7. take ( 2 × 2) inverse discrete cosine transform for coefficient in step 6 to get stego-image. detection algorithm figure 2 represent the detection algorithm as 1. take ( 2 × 2) discrete cosine transform of stego-image. secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 222 2. state ( 8 × 8) coefficients of dct of step1. 3. take ( 32 ×32) inverse discrete cosine transform for coefficients stated in step 2 to get internal image. 4. take ( 32 ×32) discrete cosine transform for internal image. 5. state ( 4×4) coefficients of dct of step4. 6. any value assume '1' and any value approach to zero assume zero for coefficients stated in step 5 "i.e. value*exp(-10)  zero ". 7. decoded 1, 0 to letter using ebcdic and get the secret message. experimental results: this section presents experimental results obtained for two cover-image sets. the first set of coverimages consists of four standard grayscale images, (a), (b), (c), and (d) in figure 3, each of 512  512 pixels (with height 50 % and width 50 %). the second set of cover-images consists of four standard grayscale images, (a), (b), (c), and (d) in figure 4, each of 64  64 pixels (with height 100 % and width 100 %). (experiment 1, experiment 2, experiment 3, and experiment 4) described embedded the message encoded by using ebcdic for each letter into ( 32 × 32) dct coefficients of the internal set coverimages of size 64 × 64 pixels that distribute in (2 × 2) dct coefficients of the external set coverimages of size 512 × 512 pixels as shown in figure 5, than take ( 2 × 2) inverse discrete cosine transform to get stego-image as shown in figure 6. detect the internal set cover-images of size 64 × 64 pixels as shown in figure 7. table 4 shows the result for experiment 1, any value assume'1' and any value approach to zero assume zero for coefficients above to get secret message " jackdaws love my big sphinx of quartz". the mean square error (mse) and peak signal to noise ratio psnr shown in equation 1,2 to determine the error between stego-images and original images   2 '1 ii nm mse cc (1) i : is the original image ' i : is the stego-image mc: is the row size of image nc: is the column size of image db mse psnr 2 255 log10 (2) table 3 shows the values of rmse's and psnr's of stego-images that embed an image. conclusions in this paper, data hiding technique is proposed able to embed massage encoded ebcdic into a dct's coefficients of (64×64) pixel grayscale image that embedded in dct's coefficients of (512×512) pixel grayscale image while guaranteeing the high psnr of the marked image versus the original image and low mse. the hidden data can be extracted without using the original image, the secret message can be extracted efficiently, and unrecognizable effect on internal image due to embedding procedure references ahmed hassan hadi 222 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 bender w., morimoto n., lu a., (1996), "techniques for data hiding," ibm syst. j. 35 (3/4) pp. 313–336. bhattacharjya a. k. and ancin h., (1999), "data embedding in text for a copier system," in proc. ieee icip’99, vol. 2,kobe, japan, pp. 245–249. cheddad a., condell j., curran k., and kevitt p., (2010), "digital image steganography: survey and analysis of current methods", elsevier signal processing, vol. 90, issue 3, pp. 727-752. chen t.s., chang c.c., hwang m.s., (1998), "a virtual image cryptosystem based upon vector quantization," ieee trans. image process.vol. 7, no. 10, pp. 1485–1488. chung k.l., shen c.h., chang l.c., (2001), "a novel svdand vq-based image hiding scheme," pattern recognition lett. 22(9), pp. 1051–1058. marvel l.m., boncelet c.g., retter c.t., (1999), "spread spectrum image steganography," ieee trans. image process. vol.8, no. 8, pp. 1075–1083. matsui k. and tanaka k., (1994), "video-steganography: how to secretly embed a signature in a picture," proc. ima intellectual property project, vol. 1, no. 1. maxemchuk n. f. and low s., (1997), "marking text documents," in proc. ieee icip’97. pang h. h., tan k. l., and zhou x., (2004), "steganographic schemes for file system and b-tree," ieee transaction on knowledge and data engineering, vol. 16, no. 6, pp. 701-713. pavan s., sridhar g., and sridhar v., (2005), "multivariate entropy detector based hybrid image registration," ieee icassp, vol. 2, pp. 873-876. wang r., lin c., lin j., (2000), "hiding data in images by optimal moderately significant-bit replacement," iee electron. lett. 36 (25) , pp.2069–2070. zhang x., (2011), "reversible data hiding in encrypted image," ieee signal processing letters, vol. 18, no. 4., pp. 255-258. secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 222 table 1 the extended binary-coded decimal interchange code (ebcdic) table 2 coding message by ebcdic ahmed hassan hadi 222 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 table 3 values of rmse's and psnr's of stego-images that embed an image. table 4 the result for experiment 1: any value assume'1' and any value approach to zero assume zero for coefficients below to get secret message secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 232 ahmed hassan hadi 232 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 figure 1 block diagram represent the insertion algorithm figure 2 block diagram represent the detection algorithm secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 232 figure 3 the external set cover-images of size 512 × 512 pixels (with height 50 % and width 50 %). figure 4 the internal set cover-images of size 64 × 64 pixels (with height 100 % and width 100 %). ahmed hassan hadi 233 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 figure 5 (2 × 2) dct coefficients of the external set cover-images of size 512 × 512 pixels including ( 32 × 32) dct of the internal set cover-images of size 64 × 64 pixels that embedded the message encoded by using ebcdic for each letter. secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 232 figure 6 stego-images obtained of size (with height 50 % and width 50 %). figure 7 detect the internal set cover-images of size 64 × 64 pixels (with height 100 % and width 100 %). water quality monitoring of al-hawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 222 water quality monitoring of al-hawizeh marsh m.sc. eman abd mohammed environmental engineering department collage of engineering al-mustansiriya university abstract the mesopotamian marshlands faced a massive destruction from the year 1990 till 2003. this destruction leads to displace the marsh dwellers and decrease the numbers of flora and fauna in the region. after the war in 2003 in iraq the rehabitation and restoration of the devastated marshland ecosystem started. in this study a survey was made on the physical and chemical characteristics of alhawizeh marsh for an interval and creates comparison among these characteristics during the four season’s then format a relationships between water salinity and electrical conductivity and another relationship between turbidity and total suspended solid. it was found that the water quality of alhawizeh marsh for most of the properties was good in summer time because of the flood water from tigris and the other feeders of the marsh. some properties of al-hawizeh marsh was coincide with the maximum allowable values of the iraqi drinking standards (1986). the equation between the salinity and electric conductivity was exponential equation while between the turbidity and the total suspended solid was power equation. key word: marsh, mesopotamian, hawizeh marshland, turbidity, tss. مراقبة نوعیة میاه هور الحویزة ایمان عبد محمد. م.م قسم هندسة البیئة-كلیة الهندسة-الجامعة المستنصریة الخالصة هذا التدمیر ادى الى هجرة . ٢٠٠٣الى ١٩٩٠ان االهوار في بالد مابین النهرین قد تعرضت الى تدمیر كبیر من عام تم في هذه . المدمرةاالهواروأحیاءبدأت عملیة اعادة تأهیل٢٠٠٣بعد حرب . منطقةساكني االهوار والى نقصان نباتات وحیوانات ال الدراسة اجراء مسح على الخواص الفیزیاویة والكیمیاویة لهور الحویزة خالل فترة معینة ومقارنة هذه الخواص خالل فصول السنة االربعة وقد .العكورة وتركیز المواد الصلبة الكلیةبین اخرىعالقةو ل الكهربائي ومن ثم تكوین عالقة ریاضیه تربط بین ملوحة الماء والتوصی كانت جیدة خالل فصل الصیف بسبب ، بالنسبة ألغلب الخواص،وعیة میاه هور الحویزة ن-:ه الدراسة الى التاليتم التوصل في هذ بعض خواص میاه الهور كانت متطابقة مع القیم العلیا .كمیة المیاه الكبیرة القادمة الى الهور من نهر دجلة وبقیة مغذیات الهور al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 223 اسیة وهي عالقة اسیةتوجدعالقة تربط الملوحة بالتوصیل الكهربائي . ١٩٨٦المسموحة لمیاه الشرب حسب المواصفة العراقیة لعام exponential equationوهي عالقة اسیةوعالقة بین العكورة وتركیز المواد الصلبةpower equation. introduction wetlands mean simply the land that is wet, the land that is saturated with water(water and land resources,1998).marshes are frequently or continually flooded wetlands characterized by emergent herbaceous vegetation adapted to saturated soil condition, changing water flows, and mineral soil. marshes are the most common wetlands types in north america and south of iraq (usepa, 2008). marshes recharge groundwater supplies and moderate stream flow by providing water to streams. this is especially important function during periods of drought. the presence of marshes in watershed helps to reduce damage caused by floods by slowing and strong flood water. historically , people lived and around the wetlands and in the interior of the marshes, and derived both subsistence and market economies from extractive uses such as harvesting reeds, water buffalo dairy products, fish, water, foul and agriculture. all iraqi marshlands are located in south of iraq in the longitude between (e 48º 00') from east to (e 46º) from the west and the latitude between (n 31º 50') from the north to (n 30º 30') from the south (kadhem, 2005). marshlands are part of three governorates in south; basrah, amarah, and thi-qar. the areas of all marshlands before drying are 20000 km², while the areas of the three governorates are 33577 km².marsh in iraq is typically divided into the three major areas: al-hammar, south of the euphrates; the central marshes between the twin rivers; and al hawizeh marshes east of the tigris river (abbas,2006), as shown in figure(1). following the end of the gulf war in 1991, the marsh dwellers were important elements in the uprising against the previous regime. to end the rebellion, the regime implemented an intensive system of drainage and water diversion structures that desiccated over 90% of the marshes(partow, 2001). the reed beds were also burned and poison introduced to the waters (nicholson, 2002). alhawizeh marsh locates to the east of the tigris river in misan governorate and extended to the iranian territory (known there as al-azim marsh), as shown in figure (1) (evans , 1995 ) alhawizeh marsh covered at least 3,000 square kilometer of area in the flood time and less of hundreds square meters in summer time (unep,2001, hamadani, 1984).the major portion is located in iraq covering an average area of 3500 km² during the flooding season. this marsh is reduced to 650 km² during the drying (abbas, 2006). the data the chemical and the physical tests include ; air and water temperature, ph, salinity, turbidity, total suspended solids (tss), total dissolved solids (tds) , electrical conductivity (ec), dissolved oxygen (do), biochemical oxygen demand (bod) , total hardness (t.h.) ,calcium , magnesium , bicarbonate, chloride and sulfate, the data are from the iraqi foundation , the data in table (1) represent the average of four values for each items , these four values collected from four stations in the marsh , the locations of these stations is (station(1) n 31o 34'7.56" e 47o 30'31.38"; station(2) n 31o33'44.51" e 47o 30'36.53"; station(3) n 31o 37'11.37" e 47o 35'20.51"; station (4) n 31o35'36.89" e 47o 38'45.11") .the instruments used for measuring the water parameters are: thermometer for al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 224 temperature, hanna(hi93703) for turbidity, the (wtw) 340i for measuring ph, conductivity, salinity, tds, and do , the bod5 can be calculated by subtracting dissolved oxygen after five days from the time of sampling, the t.h. and ca+2 were calculated by titration with edta standard solution, the estimation of mg+2 was : (t.h.-cah)*0.243=mg where: cah is the calcium hardness and t.h. is the total hardness. the estimation of hco3values was by the titration with standard sulfuric acid solution, clvalues were estimated by titration with silver nitrate standard solution, and so4-2 was estimated by using spectrophotometer. result and discussion from figures (2) and (3) which show the air and water temperatures for al-hawizeh marsh during the year, the minimum temperature of air and water in al-hawizeh marsh was in february and january respectively; and the maximum temperatures of air and water were in july and august respectively. figure (4) shows the turbidity values for al-hawizeh marsh, figure (5) explain a decreasing in salinity in summer season because of the dual action of the high extension of vegetation in these months. figure (6)shows that the minimum concentration of bod were in summer time because of the dual action of the high extension of vegetation in these months, the high concentrations of the bod5 in the fall and winter are because of the decomposition of the aquatic plants. figure (7) show that the maximum values of ec occur in spring (just like the tds values as shown in figure(8) the low ec values in summer time is because of the dilution by the relatively higher water level and the high vegetation extension. figure (9) show the variation in the concentration of the total solid in all seasons. one can see the relative similarity in turbidity and tss graphs and this is because the tss is causing the turbidity in the water samples. figure (10) explain the values of ph for al-hawizeh marsh; which was almost lower in the fall season than the other seasons and that may be caused by the production a weak acid, called "carbonic" acid resulted from the combining of water with the carbon dioxide (co2) from organic substances decomposition and the ph values were within the range of iraqi drinking standards(1986) (6.5-8.5). figure(11) explain that the decreasing in concentration of t.h. in summer time because of the dilution caused by relatively higher water levels(unep, 2003) and the action of the extended vegetation (imet, 2006) . on the other hand the high concentrations in fall and winter seasons are caused by the low water levels. figure (12) show that high do concentrations in winter time are because of the lower temperatures which lead to increase the ability of water to contain oxygen. figures (13) and (14) show that the calcium and magnesium concentrations decreasing in summer time because of the dilution caused by relatively higher water levels. on the other hand the high concentrations in fall and winter seasons are caused by the low water levels. the concentration of calcium was within the limit of iraqi al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 225 drinking standards (1986) (less than 200 ppm) and the concentration of magnesium was within the limit of iraqi drinking standards (1986) (less than 150 ppm). figure (15) show the concentration of bicarbonate for al-hawizeh marsh. the high ph value in spring is due to the flood water which led to raise the alkalinity in the water because of the type of soil in the area . figure (16), and (17) explain that there is a decreasing in concentration of chloride and sulfate in summer is because of the dilution caused by relatively higher water levels and the action of the extended vegetation (imet, 2006, al-khazrajy, 2006). on the other hand the high concentrations in fall and winter seasons are caused by the low water levels. the concentration of chloride was within the limit of iraqi drinking standards (1986) (less than 600 ppm). the change in salinity and electrical conductivity values for al-hawizeh marsh during the year was shown in table (1), the best equation between salinity and electrical conductivity for al-hawizeh marsh is exponential equation (y=814.77e 0.8664x) where x is the salinity and y is the electrical conductivity. for this equation the correlation coefficient is 70.1%; as shown in figure (18) and table (2). while the best equation between turbidity and tss for al-hawizeh marsh is power equation (y=1.0307x 0.9762) where x is the turbidity and y is the tss. for this equation the correlation coefficient is 43.9%; as shown in figure (19) and table (3). conclusions and recommendations the following conclusions may be derived from the following research: 1from the comparison between the physical and chemical properties of water, it has been found that the best properties were in summer. 2there was an exponential relationship between the salinity of water and electrical conductivity. 3there was a power relationship between the turbidity of water and the total suspended solid concentration. the following recommendation may be derived from the following research: 1it is recommended to do researches about soil characteristics before reflooding new areas; since the soil may have toxic materials that can be transferred as dissolved phase to all over the marsh. 2it is recommended to monitor the changes in water, vegetation and soil surface area and characteristics frequently, by using high resolution images and accurate instruments and laboratories. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 226 references abbas, s.f., (2006), "application of hydrodynamic model in abu zirig marshland", m.sc.thesis, university of al-mustansiriya. al-khazrajy, k.a., (2006),"a tectonic study of the marshes south of iraq using geophysical and sedimentological data". ph.d. thesis, university of baghdad. evans, m., i., (1995) ."important birds areas in the middle east ".bird life international, p184. hamadani, s. m., (1984), "gleams of irrigation development in iraq before and recently". sadoon press.(arabic). imet. ,(2006), " overview of present conditions and current use of the water in the marshlands area" .book 4.iraq foundation. kadhem, a. j., (2005), "water quality monitoring of abu zirig marsh in southern iraq after drying", m. sc. thesis, university of al-mustansiriya. nicholson, e. and p. clark (eds). ,(2002), "the iraqi marshlands: a human and environmental study". the amar appeal international charitable foundation. partow, h., (2001), "the mesopotamian marshlands: demise of an ecosystem". report united nations environmental program, 58pp, http://earthobservatory.nasa.gov/newsroom/newimages/meso2.pdf. unep, hassan partow., (2001), "the mesopotamian marshlands: demise of an ecosystem. early warning and technical assessment report". unep/dewa/tr.01-3 rev.1, division of early warning and assessment, united nations environmental programme, nairobi, kenya. unep, (2003), " environment in iraq: unep progress report".nep. geneva, switzerland. u.s. environmental protection agency (usepa), (2008),"marshes", http://www.epa.gov/owow/wetlands/types/marshes. water and land resources, (1998)," wetlands, bogs, ponds, marshes and meadows", http://dnr.metrokc.gov/wlr. http://earthobservatory.nasa.gov/newsroom/newimages/meso2.pdf http://www.epa.gov/owow/wetlands/types/marshes http://dnr.metrokc.gov/wlr al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 227 figure (1): the iraqi marshes (partow, 2001) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 228 table(1):the tests results for al-hawizeh marsh (from iraqi foundation). date a ir t em p. (° c ) w at er t em p. (° c ) t ur bi di ty (f t u ) sa lin ity (p pt ) c on du ct iv ity (µ s/ cm ) ph b o d (m g/ l ) t d s (m g/ l ) t ss (m g/ l ) t ot al h ar dn es s (t .h .) (m g/ l ) d o (m g/ l ) c a+ 2 (m g/ l ) m g+ 2 (m g/ l ) h c o 3(m g/ l ) c l(m g/ l ) so 42 (m g/ l ) nov, 2005 28.25 17.70 17.69 0.83 1688.5 7.88 7.53 1050 6.77 785 4.55 97.46 108.38 206.67 451.38 485.50 dec, 2005 22.00 16.00 17.74 0.63 1138.7 5 7.50 6.23 905.75 11.76 905 4.31 110.23 152.85 244.21 336.81 265.10 jan, 2006 22.10 12.20 19.12 0.71 1314.5 7.79 5.78 942.75 16.63 635 7.35 72.43 109.36 170.83 487.2 324.26 feb, 2006 18.30 15.09 23.66 0.73 1290 7.79 7.35 1142.5 18.25 650 3.48 160.32 60.78 213.29 212.59 264.00 mar, 2006 22.50 18.20 22.13 0.85 1987.5 8.01 5.73 1501 14.25 495 4.95 83.19 60.57 207.71 274.74 436.71 apr, 2006 26.75 22.73 15.52 0.38 1186.2 5 7.69 9.00 873.5 13.25 340 5.30 66.13 42.54 298.95 310.19 242.26 may, 2006 30.15 27.28 24.63 0.40 1237.5 7.86 6.23 983 40.78 395 4.85 66.12 43.36 274.54 465.65 247.88 jun, 2006 35.55 25.68 24.86 0.25 957.5 7.65 4.30 810.5 29.50 220 6.68 56.12 21.97 250.14 194.99 128.11 jul, 2006 39.60 27.60 19.10 0.25 970.25 7.86 3.58 741 35.75 350 5.13 80.15 36.45 219.64 159.57 143.75 aug, 2006 36.00 31.48 16.01 0.50 1405 7.78 5.23 1210 35.25 515 4.97 112.23 57.12 237.97 354.51 366.44 sep, 2006 33.00 28.35 30.51 0.40 1252 7.04 6.23 848 27.75 490 3.45 124.25 43.74 290.94 221.57 285.07 oct, 2006 31.75 24.80 33.99 0.75 1796.2 5 7.43 6.37 788.5 29.5 616.5 5.03 122.20 78.35 204.43 425.35 437.93 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 229 table (2): showing the type of equation & correlation coefficient between salinity & electrical conductivity for al-hawizeh marsh. type of equation linear logarithm polynomial power exponential correlation coefficient, r2 % 67 63.1 69.9 68.6 70.1 table (3): showing the type of equation & correlation coefficient between turbidity & tss for al-hawizeh marsh. type of equation linear logarithm polynomial power exponential correlation coefficient, r2 % 14 14.2 14.5 19.2 19 figure (2): air temp. values of al-hawizeh marsh. figure (3): water temp. values of alhawizeh marsh. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 230 figure (4): turbidity values of al-hawizeh marsh figure (5): salinity values of al-hawizeh marsh figure (6): bod values of al-hawizeh marsh figure (7): conductivity values of alhawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 231 figure (11): hardness values of al-hawizeh marsh figure (10): ph values of al-hawizeh marsh figure (8): tds values of al-hawizeh marsh figure (9): tss values of al-hawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 232 figure (13):the calcium concentration of al-hawizeh marsh figure (12):the dissolve oxygen values of al-hawizeh marsh figure (14):the magnesium concentration of al-hawizeh marsh figure (15):the bicarbonate concentration of al-hawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 233 figure (18) : relationship between salinity and electrical conductivity. figure (19): the relationship between turbidity & tss for al-hawizeh marsh. figure (16):the chloride concentration of al-hawizeh marsh figure (17):the sulfate concentration of alhawizeh marsh template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 158 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. experimental investigation of model piles in sloping ground subjected to surcharge loads mohammed khachi hatem, al-mustansiriyah university, faculty of engineering, baghdad, iraq. email: mohammedkhachi@yahoo.com mohammed hussein al dahlaki, al-mustansiriyah university, faculty of engineering, baghdad, iraq. email: mohammed.aldahlaki@gmai.com hassan fallah hassan, al-mustansiriyah university, faculty of engineering, baghdad, iraq. email: hassanfala@gmail.com received on 18 january 2017 accepted on 19 february 2017 abstract: this study deals with experimental studying of the influence of an adjacent surcharge loads on pile's behavior in both horizontal and sloping ground surface. a number of laboratory tests were performed on instrumented aluminum pipe piles of 25 mm outer diameter embedded in sandy soil subjected to surcharge load. the study took into consideration the effect of surcharge intensity, sloping ground and soil's relative density on lateral deformation of piles in terms of displacement and bending moment. the study was performed on different sloping ground [vertical to horizontal (v:h)] such as, "1v:3h", "1v:2.5h", "1v:2h" and "1v:1.5h", in addition to horizontal ground. three different relative densities of sand (29% , 50% and 75%) were adopted in this study. the results showed that the increasing in the surcharge loads increases lateral displacement and bending moments of piles in horizontal and sloping ground surface. it was also calculated that the bending moments and displacement of piles increase with increasing sloping ground and decreasing relative density of soil. keywords: pile, sand, surcharge load, sloping ground, relative density, lateral displacement and bending moment. 1. introduction pile foundations are primarily used for providing resistance against direct "active" loads (vertical, lateral or both) which are directly applied to the pile head by a structure.however, with rapid development of cities and transportation systems, pile in existing structure is also subjected to indirect "passive" loads induced from lateral soil movements due to surcharge loading, tunneling operation, deep excavation, pile driving operation, etc. besides, there are situations where piles are designed for stabilizing the moving mailto:mohammedkhachi@yahoo.com mailto:mohammed.aldahlaki@gmai.com mailto:hassanfala@gmail.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 159 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. slopes and liquefiable soils. in all these conditions, the ground movement may inform extra force, cause increase in the lateral deformation of piles which may finally cause problems and even damage to the structure of piles (pan et al, 2002 and al-abboodi et al, 2015).although the soil movement is likely in both lateral and vertical directions, lateral ground movements are more important as pile foundation is not designed for sustaining important lateral load (bauer et al, 2014). several authors, such as bransby (1995), yang et al. (2002), poulos (2007) and karkush and jafar (2015) conducted many laboratory tests for investigating the effect of an adjacent surcharge loading on pile's behavior in horizontal ground surface. the results showed that the surcharge load increases the lateral displacement of piles. mezazigh and levacher (1998) , zhang et al. (2004), begum et al. (2008), sivapriya and gandhi (2011), muthukkumaran(2014) and muthukkumaran and begum (2015) investigated the pile's behavior in sloping ground subjected to horizontal active load at their head. they found that the horizontal force capacity of piles decreases with increasing sloping ground surface and decreasing the relative density of soil or shear strength of soil. muthukkumaran et al. (2004) investigated influence of applied surcharge loads on pile's behavior embedded in both horizontal and slope surface of 1v:1.5h (i.e., 1 vertical to 1.5 horizontal). the results found that the displacements of piles in slope surface condition are higher than that in horizontal condition. muthukkumaran and krishnan (2012) and sharafi and sojoudi (2016) , presented three dimensional finite differences analyses for investigating the pile's response in different slope surface subjected to surcharge loads. however, all these studies with the exception of muthukkumaran et al. (2004) have been directly towards the behavior of piles in either horizontal ground under surcharge loads or in sloping ground under lateral active loads. therefore, the present study aims to examine the influence of an adjacent surcharge loads on pile embedded in horizontal and different sloping ground with different relative densities of sandy soil. the engineering properties of sand, details of experimental apparatus, sand placement method, measurement system and properties of tested pile are described below. 2. soil properties clean dry sand was used in this study for all the tests as a model ground, it was sieved on the sieve no (10) to remove the coarse particles.table (1) shows the physical and mechanical properties of this sandy soil .it is classified as poorly graded sand (sp) based on the "unified soil classification system" (uscs). table (1): physical and mechanical properties of sand property value specific gravity, gs 2.65 d10 (mm) 0.18 d30 (mm) 0.31 d50 (mm) 0.41 d60 (mm) 0.48 coefficient of curvature, cc 1.11 coefficient of uniformity, cu 2.67 uscs-soil type sp maximum dry unit weight, γdmax, kn/m 3 16.78 minimum dry unit weight, γdmin, kn/m 3 14.1 angle of internal friction degree( for dr = 29% ) 30 angle of internal friction degree( for dr = 50% ) 33 angle of internal friction degree( for dr = 75% ) 39 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 160 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. tested pile hollow aluminum pipes of 25 mm outer diameter, 1.2 mm wall thickness and 600mm embedded length with a bottom plugged was adopted as a model pile in this study. the pile's flexural stiffness was calculated by performing simply supported beam test. by measuring the deflection at the center the model pile of under a given load, pile's flexural stiffness was found (351 ×10 6 n.mm 2 ). figure (1): test set up 4. test set-up an experimental apparatus was designed and fabricated for the current study to investigate the effect of an adjacent surcharge loading on pile foundation embedded in sloping ground. it consisted of four main parts (i.e., steel box, loading system, sand raining system and measurements system). figure (1) shows the overall arrangement of the testing apparatus and all the component details are presented below. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 161 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.1. steel box the experimental study was performed on the model pile in a rectangular steel container with the size of 1.8 m length x 1 m width x 1 m height. the steel container was made of thick steel plate having a thickness of 6.5 mm. the dimensions of the box were designed such that to eliminate the boundary effects in the result. 4.2. loading system the loading system includes the load reaction frame, hydraulic jack and square plate (square footing). the load reaction frame consisted of two vertical c-channels (as vertical columns) and horizontal c-channel (as a horizontal beam). a square steel plate of size 350 mm × 350 mm with 40mm in thickness was used as a square footing. the hydraulic jack (with capacity of 10 tons) was used to apply vertical loading on the instrumented pile (to insert the pile in sand) and also to apply vertical loading on the square footing (surcharge loading). 4.3. sand raining system the sand raining technique of sand placement can produce the most uniform and reproducible deposits (pathak and dalvi, 2011) .this technique was adopted for pouring the sand in the steel box since this method is simple to adopt and forms the most uniform and reproducible sand beds and is able to reproduce a greater range of sand densities. a special raining device was fabricated from timber pieces, having internal dimensions of 1780 mm by 980 mm, and 150 mm. the sand raining base was perforated with 6 mm diameter holes on a 40 mm by 40 mm grid pattern. the sand raining is suspended over the box with a guide at each of the four corners; it is then connected to a hand winch by means of pulley system. the winch permits the sand raining to move up or down within the guide frame. the velocity of the raining sand is controlled by varying the fall height, which is maintained at a constant. a number of calibration tests were carried out to find the relationship between falling height and the density of the sand, and to allow a suitable height to be chosen for raining the sand in the testing box. the results of these calibration tests are plotted in figure (2). figure (2): falling height versus relative density of sand al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 162 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.4. measurements system a load cell with a capacity of 10 tons was connected with the hydraulicjack to measure the applied vertical load on the square footing (surcharge load). the model pile in each test was instrumented with seven pairs of strain gauges (tml type fla-5-23-3l) attached along its shaft. the gauge length, gauge factor and gauge resistance were 5mm, 2.16 and 120 ohm, respectively. the strain gauges were wired in pairs to constitute halfbridges for measuring the bending moments along the pile's shaft during the test. a handheld digital data logger (tc-32k) combined with switching box (csw-5a) were used for recording and storing data from strain gauge measurement for each pile test. since seven pairs were attached along pile's shaft, two sets of data loggers and switching boxes were used in this study.the strain gauges were calibrated by testing the instrumented pile as a simply supported beam under known applied bending moments. dead loads and a pair of strain gauges were putted at the beam's center (instrumented pile's center) for applying bending moments and measuring the strains, respectively. the aim of this calibration was to find the relationship between the strain gauge readings and the bending moments. a linear relationship was obtained between the bending moment and the strain response for pile used in this study as shown in figure (3). a linear variable differential transformer (lvdt) of 100mm full range was attached on the pile at the sand surface to measure the lateral pile head displacement. figure (3): calibration of strain gauges 5. testing procedure the tests were conducted on instrumented pile inserted in both horizontal and different sloping ground with different relative densities. the sand was placed in the steel box for three different relative densities say 29 % , 50 % and 75% by using sand raining method. after the sand was filled the steel box, the hydraulic jack was used to insert the instrumented pile into the sand to a desired embedded length. prior to the pile installation process, the pile is initially pushed by hand into the sand, with the pile tip penetrating about 50 mm in the sand. the pile was located in the top edge of the slope for sloping ground condition and the same position was used for horizontal ground condition. when the installation process of the instrumented pile was finished, a required slope was constructed with cutting process. the square footing was placed near the crest of the slope and the loads were applied slowly on the soil through the jack with increment of 5 kn. the readings of the strain gauges, lvdt and load cell were recorded at each increment load. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 163 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 6. results and discussion 6.1. pile head displacement the surcharge loads were applied through the hydraulic jack and lvdt was utilized for measuring the lateral displacement of the model pile. initial tests were performed on the condition of piles in horizontal ground surface followed by the sloping ground ("1v:3h", "1v:2.5h", "1v:2h" and "1v:1.5h") with different relative densities of soil (29%, 50% and 75%). the first test was conducted on pile embedded in horizontal surface sand of 50% relative density (for convenience in comparison with other cases, this test was referred to hereafter as the "reference" test). figure (4) presents the relationship between the pile's displacement and the applied surcharge load for "reference" test. it can be noticed that the pile's displacement increases with increasing the surcharge load which is due to the increment in the lateral soil movement. for investigating the influence of slopes ground on the surcharge load-pile head displacement curve, four tests were performed on piles embedded in different sloping ground with the same density of the "reference" test ( dr =50%). the relationship between the surcharge loads and the pile's displacement for different sloping ground ("1v:3h", "1v:2.5h","1v:2h" and "1v:1.5h"), together with that for the "reference" test (horizontal ground) is presented in figure (5). it can be noticed that, the pile head displacement increases with increasing in the sloping ground. this increment is because of the decrease in passive resistance of the soil in front of the pile. at 40 kn surcharge load, the pile head displacement increases by (13%), (29%), (118%) and (250%) as the soil surface changes from horizontal to sloping surface of "1v:3h", "1v:2.5h", "1v:2h" and "1v:1.5h" respectively. for exploring the influence of relative density on the surcharge load-pile displacement curve, different tests were performed on the model pile embedded in both horizontal and sloping ground corresponding to different relative densities (29%, 50% and 75%). figure (6) presents the influence of the relative density of sand on the load-displacement curves embedded in horizontal ground surface. it can be noticed that, the pile displacement decreases with increasing sand's relative density. at 40 kn surcharge load, the pile head displacement deceases by (25%) and (37%) as the relative density of sand increases from 29% to 50% and al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 164 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. from 50% to 75% respectively. figures (7, 8, 9 and 10) demonstrate the relationships between the surcharge loads and pile's displacement in sloping ground of "1v:3h", "1v:2.5 h", "1v:2h" and "1v:1.5h" respectively for different relative densities of sand. it clears that, the pile displacement increases with increasing the sloping ground but the rate of the increase reduces as the density increases. the highest value of pile's displacement is found about 34 mm (425% more than that for "reference" test) in the case of pile embedded in slope surface of "1v:1.5h" with 29% relative density. figure (5): surcharge load versus pile head displacement for different sloping ground figure (6): surcharge load versus pile head displacement in horizontal ground for different relative densities of sand. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 165 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (7): load displacement for pile in 1v:3h sloping ground. figure (8): load displacement for pile in 1v:2.5h sloping ground. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 166 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (9): load displacement for pile in 1v:2h sloping ground. figure (10): load displacement for pile in 1v:1.5h sloping ground. 6.2. bending moment figure (11a) presents the profiles of the bending moments along pile's shaft for "reference" test corresponding to different values of surcharge load. it clears that the bending moment's profiles are essentially the same in the shape for all the values of the applied surcharge, but the magnitude of the bending moment increases with increasing the load which is due to the increment in the lateral soil al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 167 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. movement. because of the interval of 75 mm between two adjacent pairs of strain gauges along the pile's shaft, the recorded maximum bending moment's depth may not really correspond with the accurate depth. figure (11): bending moment versus surcharge load for the "reference" test figure (11b) presents the relationship between the maximum bending moments and the applied surcharge load for "reference" test. it is established that the maximum bending moments increase with the increment in surcharge loads but the rate of increase reduces, especially when the surcharge load is greater than about 35 n because of the decreasing in the ground resistance. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 168 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (14): bending moment profile for different sloping ground with 75% relative density figure (13): bending moment profile for different sloping ground with 50% relative density the distribution of bending moments along the pile's shaft at different sloping ground with different relative densities of sand corresponding to 40 kn surcharge load is presented in figures 12 to 14. figure (12) represents the bending moments variation along pile's shaft for different sloping ground (i.e., horizontal, "1v:3h", "1v:2.5h", "1v:2h" and "1v:1.5h") corresponding to 29% relative density of sand. figure (12): bending moment profile for different sloping ground with 29% relative density the same bending moment profiles with 50% and 75% relative densities are presented in figures (13 and 14) respectively. based on these plots, it can be seen that the bending moments increase with increasing the sloping ground because of the decreasing in the passive resistance at the top zone of the ground mas. for both horizontal and sloping ground, the maximum bending moments decrease with increasing the sand's density because of the increment in the shear strength of the soil. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 169 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (15) presents the relationship between the moments and the slopes of soil surface with different relative densities of sand. it can be noticed that, the bending moments decrease with increasing the relative density. the maximum moment increases by 189 % as the soil surface transfers from horizontal to "1v:1.5h" slope surface with same relative density (dr = 50%). also, for sloping ground of 1v:1.5h, the moment deceases by (22%) and (11 %) as the sand's relative density changes from 29% to 50% and from 50% to 75% respectively. the highest value of the maximum moment is obtained in the condition of pile embedded in "1v:1.5h" slope with 29% relative density (about 240% greater than that for "reference" test) while the lowest vale is obtained in the case of pile embedded in horizontal ground surface with 75% relative density of soil (about 16 % smaller than that for "reference" test). figure (15): maximum bending moment versus sloping ground with different relative densities 7. conclusions laboratory model tests have been conducted on pile in both horizontal and sloping ground surface corresponding to different relative densities adjacent to surcharge loads. the results of the tests indicate that the deformation of pile in terms of displacement and bending moment increases with increasing in surcharge loadings and sloping ground. also, the deformation of pile decreases with increasing the relative density of sand. the highest values of pile's displacement and moment are found in the case of pile in sloping ground of "1v:1.5h" corresponding to 29% relative density while the lowest values are found in the case of horizontal surface corresponding to 75% relative density. the displacement of pile is considerably increased as the surface transfers from horizontal to sloping surface. its value increases by 13%, 29%, 118% and 250% as the ground transfers from horizontal to sloping surface of "1v:3h", "1v:2.5h", "1v:2h" and "1v:1.5h", respectively. the displacement of pile decreases with increasing the relative density of sand for all ground surface conditions. for 40 kn surcharge load in the case of horizontal ground, the pile displacement deceases by (25%) and (37%) as the relative density of sand increases from 29% to 50% and from 50% to 75%, respectively. the maximum bending moment decreases by 16% when the relative density of sand increases from 50% to 75%. for 40 kn surcharge load and 50 % sand's relative density, the pile's bending moment increases by 9 %, 26 %, 58 % and 90% as the ground transfers from horizontal to slopes of "1v:3h", "1v:2.5h", "1v:2h" and "1v:1.5h", respectively. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 170 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. references 1) pan, j. l., goh, a. t. c., wong, k. s., & selby, a. r. (2002). "three dimensional analysis of single pile response to lateral soil movements", international journal for numerical and analytical methods in geomechanics, 26(8), 747-758. 2) al-abboodi, i., toma-sabbagh, t. m., and al-jazaairry, a. (2015). "modelling the response of single passive piles subjected to lateral soil movement using plaxis", international journal of engineering research and technology, 4(3), 176-180. 3) baue, r j., kempfert h.g. and reul o. (2014). "lateral pressure on piles due to horizontal soil movement -1 g model tests on single piles and pile rows", proceedings of the 8th international conference on physical modeling in geotechnics, (icpmg2014), perth, australia. 4) yang, m., zhu, b. t., & chen, f. q. (2002). "pilot study on collapse of an industrial building due to adjacent surcharge loads", chinese journal of geotechnical engineering-chinese edition-, 24(4), 446-450. 5) poulos, h. g. (2007)."design charts for piles supporting embankments on soft clay", journal of geotechnical and geoenvironmental engineering, 133(5), 493-501. 6) bransby, m. f. (1995). "piled foundations adjacent to surcharge loads", ph.d. thesis, university of cambridge. 7) karkush, m. o., and jafar, g. s. "effects of surcharge on the behavior of passive piles in sandy soil", international journal of scientific and engineering research 6(10), 392-397. 8) muthukkumaran, k., sundaravadivelu, r., & gandhi, s. r. (2004). "effect of sloping ground on single pile load deflection behavior under lateral soil movement", proceedings of the 13th world conference on earthquake engineering, vancouver, bc, canada, august (pp. 1-6). 9) sharafi, h., & sojoudi, y. "experimental and numerical study of pile-stabilized slopes under surface load conditions", international journal of civil engineering, 1-12. 10) mezazigh, s., & levacher, d. (1998). "laterally loaded piles in sand: slope effect on p-y reaction curves", canadian geotechnical journal, 35(3), 433-441. 11) zhang, l. m., ng, c. w. w., and lee, c. j. (2004). "effects of slope and sleeving on the behavior of laterally loaded piles", soils and foundation, 44(4), 99-108. 12) begum, n. a., seethalakshmi, p., and muthukkumaran, k. (2008)." lateral load capacity of single pile located at slope crest", indian geotech. j., 38(3), 278-294. 13) sivapriya, s., and gandhi, s. (2011). "behaviorof single pile in sloping ground under static lateral load", proceedings of indian geotechnical conference(pp. 199-202). 14) muthukkumaran, k. (2013). "effect of slope and loading direction on laterally loaded piles in cohesionless soil", international journal of geomechanics,14(1), 1-7. 15) muthukkumaran, k., and begum, n. a. (2015). "experimental investigation of single model pile subjected to lateral load in sloping ground", geotechnical and geological engineering, 33(4), 935-946. 16) muthukkumaran, k., and krishnan, m. g. (2012). "three dimensional analysis of piles on sloping ground subjected to passive load induced by surcharge", international journal of engineering and technology innovation, 2(1), 31-47. 17) pathak, s.r. and dalvi, r.s. (2011). "effect of sample preparation method on liquefaction of sandy soil", electronic journal of geotechnical engineering, 16, 1411-1426. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 109 optimum design of steel frames composed of tapered members using strength and displacement constraints with geometrically nonlinear elastic analysis haitham ali bady university of qadisiya \college of engineering abstract design of steel tapered member under combined axial and flexural strength is somewhat complex if no approximations are made. however, recent load resistance factor design (lrfd) of the aisc code has treated the problem with sufficient accuracy and ease. the aim of this study is to present an algorithm for the optimum design of steel frames composed of tapered beams and columns with i-section in which the width is taken as constant, together with the thickness of web and flange, while the depth is considered to be varying linearly between joints .the objective function which is taken as the weight of the steel frame is expressed in terms of the depth at each joint. both the displacement and combined axial and flexural strength constraints are considered in the formulation of the design problem .the strength constraints are expressed as a nonlinear function of the depth variables. the optimality criteria method is then used to obtain a recursive relationship for the depth variable under the displacement and strength constraints. numerical examples are presented to demonstrate the practical application of the algorithm. keywords: design, tapered, steel, axial, flexural, strength, constraints , optimum, nonlinear, stability و اإلزاحة غير موشورية و باستخدام محددي أعضاء للمنشات الحديدية المرآبة من األمثلالتصميم المرن للمنشأو السلوك غير الخطي تأثيرالمقاومة تحت باديهيثم علي آليَّة هندسة\ جامعة القادسية \ تدريسي في الخالصة المعقدة األمور االنثناء من وأحمال لمحورية المركبة ااألحمال أثيرتالموشوري تحت غير اإلنشائييعتبر تصميم العضو التابعة lrfd األمريكيةان المدونة , صياغة المعادالت التصميمية التقريبية في الحلول لم تستخدم بعض إذا الشيءبعض ان الهدف من هذا ابحث هو . بهاألبأسة للمنشات الحديدية تعاملت مع هذه المسالة بطريقة بسيطة نسبيا وبدقاألمريكيهد عللم ومكونة ) جسور , أعمدة( الموشورية أعضاء للهياكل الحديدية المؤلفة من األمثلتقديم طريقة ومن ثم مخطط انسيابي للتصميم ون متغيرا كبحيث يكون عرض المقطع مع سمك الشفة و الوتر ثابتين بينما عمق المقطع ي) i (حرف من مقاطع على شكل ولذلك تم التعبير عن هذه الدالة بداللة سمك للمنشأان الدالة المطلوبة في هذه الدراسة تمثل الوزن الكلي . لى طول ذلكع و المقاومة في كتابة المعادالت اإلزاحة بنضر االعتبار محددي األخذ تم . هالمقطع العرضي للعضو في كل نهاية من نهايتي ومن ثم وباستخدام محدد , أيضاحدد المقاومة بصيغة غير خطية وبداللة سمك المقطع تم التعبير عن دالة م . ةالتصميمي al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 110 و اإلزاحةتحت محددي ) اإلنشائيسمك المقطع ( عالقات تكرارية متتالية للمتغير التصميمي ى عدةة تم الحصول علياالمثل . ة التقنية المتبعة والبرنامج المستخدم فعاليح لتوضياألمثلةعلى مجموعة من ح المقتراألسلوبتم تطبيق . المقاومة nomenclature li is the length of the tapered member i. tf, tw, thickness of flange and web of the i-section of the tapered member respectively. bf is the width of the flange ρ and iν are the density and volume of typical tapered member i shown in fig.(1) , respectively . nm is the total number of tapered members in the frame . di is the depth variable belonging to member i, d1i is the lower bound of the depth variable . gdj (d1i , d2i) represents jth displacement constrains . gsri (d1i , d2i) represents strength constrains for member i. k is the total number of restricted displacement. jδ is the displacement at node where constraints is wanted . juδ is its upper bound. fy is specified yield stress ag is the gross area of· the member at the smaller end. effλ is called the effective slenderness parameter. sx, the sectional modulus of the larger end fb is the design flexural stress of tapered member, introduction steel frames with tapered members were preferred in the design of structure whenever the architectural requirements allow their presence .they provide better distribution of strength as well as yield lighter design. the methods available for the analysis of such frames are well established (haitham, 2000), (oran, 1974) .in most of the practical design codes , approximate procedures are suggested for dimensioning tapered members which are subjected to the combined action of axial force and bending moment . in this study, an optimum design algorithm is presented which takes into account the geometrical nonlinearity for steel frames with tapered members. this is achieved by coupling optimality criteria approach with large deformation analysis method of elastic tapered steel frame develops in ref (2). optimum design problem the optimum design problem a nonlinear steel frames composed of tapered members subjected to displacement and strength constraints can be expressed as follows : min w= ∑ = nm i ii v 1 ρ i=1,…,nm (1) subjected to gdj (d1i, , d2i) ≤ 0 j=1,…, k gsri (d1i, , d2j) ≤ 1 i=1,…,nm d1i-d1il ≥ 0 i=1… nm (2) d2i-d1il ≥ 0 i=1… nm al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 111 objective displacement the objective function, which is the total volume of frame, is obtained as a summation of weights of all members. the volume vi of member i as shown in fig. (1) can be expressed in terms of the values of the depth variables (d1) and (d2) , as follow: vi = ( ) ( ) iwffwii ltbtt dd ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ −+ + 2 2 21 (3) where d1i, d2i is the depth variables of the smallest and largest end respectively of tapered member i. of the i-section of the tapered member. it can be seen that bf, tf and tw are selected to be constant throughout the frame, which leaves only the depths at nodes (1) and (2) as the design variables. the elastic sectional modulus for symmetrical sections are calculated easily when the values of d1i and d2i are known. combined axial and flexural strength constraints the combined axial and flexural strength constraint for member i , which is subjected to axial force and bending moment about its major axis, is given in lrfd(4) as, for pu/(φ pn) ≥ 0.2 (4) 1 9 8 ≤+ nxb uxu m m np p φφ (5) and for pu/(φ pn) < 0.2, (6) 1 2 ≤+ nxb uxu m m np p φφ , (7) where pu is the required axial strength and pn is the nominal tensile or compressive strength for the member depending upon whether it is in tension or compression. mux is the required flexural strength and mnx is the nominal flexural strength about the major axis of the section. the resistance factor (φ ) is given as 0.90 in the case of tension and as 0.85 in the case of compression in lrfd. the resistance factor for flexure bφ is specified as 0.90 by the same code(hayalioglu, saka,1992). since only the nominal strengths are the functions of the depth variables, the strength constraint for member i can be re-written as: gsr(di,dj)=a1/pn+ a2/mnx, (8) where a1 and a 2 are the constants given as, for pu/(φ pn) ≥ 0.2 a1=pu/0.85 a2=8mu/8.1 (9) pu/(φ pn) < 0.2, a1=pu/1.7 a2=mu/0.9 (10) displacement constraint the jth displacement constraints gdj (d1i, , d2i) has the following form: gdj (d1i, , d2i) = juj δδ − (11) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 112 the displacement jδ can be expressed as a function of the depth variable by making use of the virtual work theorem ( ) iji nm i t ij xididkx 21 1 ,∑ = =δ (12) where xi is the vector of virtual displacements of member i due to the virtual loading corresponding to the jth constrains. this is obtained by applying the unit load in the direction of the restricted displacement j. k (d1i, d2i) is the stiffness matrix of member i in the global coordinate. xi is the displacement vector e due to applied load. nominal axial and flexural strength of tapered member it is shown from eqs. (8) to (10) that the combined strength constraint for a tapered member makes it necessary to express the design axial and flexural strength of the member in terms of depth variables defined at its ends. nominal tensile strength in the case where the tapered member is in tension, lrfd gives the nominal tensile strength pn as , gyn afp ×= (13) hence, the nominal tensile strength pn can be expressed as a function of depth variable d1, of the smaller end as pn=fy(d1tw+2t) (14) where t is a constant given by t = (tf bf – tw tf) (15) nominal compressive strength when the tapered member is in compression, its nominal compressive strength is given by lrfd as; gcrn afp ×= (16) where fcr is the critical stress computed from one of the following expressions: 5.1≤effλ fcr= )658.0.( 2 eff yf λ (17) 5.1>effλ fcr= 2 ).877.0( eff yf λ , (18) )/( 2 eqfs yeff πλ = al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 113 (19) in which s is equal to kl/roy for weak axis bending and kl/rox for strong axis bending. k is the effective length factor for the member. since between the adjacent lateral restraints, buckling about the weak axis governs, s is taken as kl/roy. the approximate radius of gyration roy is defined at the smaller end of the tapered member as, 2/1 1 3 )2(6 ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ + = ttd bt r w ff oy (20) substituting eq. (20) into eq. (19) and taking q = 1 gives the effective slenderness as, ( )[ ] 2/111 2ttdc weff +=λ (21) where c1 is a constant. ( ) ff bet klfy c 32 2 1 6 π = (22) hence, the nominal compressive strength pn of eq. (16) can be expressed in terms of depth variable di, at the smaller end as for : nominal flexural strength the nominal flexural strength of tapered flexural member for the limit state of lateral torsional buckling is given in lrfd(1) as mn = (5/3) sxfb (25) ( ) yyws y b ff ff f f 6.0 12 13/2 22 ≤ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ + −= (26) unless fb ≤ fy/3, in which case, ( )wsb fff 225.1 += (27) in eq (26) and (27) 1 12000 ldh a f s f s = , 2170000 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = to w w rlh f (28) where factors hs and hw are given as, x 5.1≤effλ ( ) ( )ttdcwn wfyttdp 21 11658.02 −××+= (23) 5.1>effλ 1/)877.0( cfypn ×= (24) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 114 hs = 1+ 0.023 f i a ldγ (29) hw = 1 + 0.00385 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ tor lγ (30) in which rto is radius of gyration of the section at the smaller end, considering only the compression flange plus 1/3 of the compression web area, taken about an axis in the plane of the web, af is the area of the compression flange, γ is given as 1 12 d dd − =γ 268.0≤ , (l/d1) or 6. (31) the relationships listed in eqns. (25)-(31) can be expressed in terms of depth variables at the ends of the tapered member as shown in the following. the sectional modulus sx ( ) 1 2 2 3 1 6 )(6 d tdtbtdt s fff fw x ++− = (32) fs and fw of eq. (28) are written as 1 12000 ldh tb f s ff s = , 1 2 4 2 3 2 dhchc cf ww w + = (33) where constants c2, c3 and c4 are c2 = 425,000tfb3f , c3 = 3l2 tf bf , c4=l2tw (34) in which γ is function of di as shown in eq. (31), and rto is ( )1 3 34 dtbt bt r wff ff to +× = (35) it is clear from eqs. (32) to (35) that nominal flexural strength mn can be expressed in terms of depth variables d1, and d2 . figures (2) to (5) shows the relationships between the nominal axial force and flexural moment strength and their derivatives with the design variables d1 & d2 .figures (6) and (7) shows the relationship between the strength constrain with the design variables d1 & d2. from these figures we can conclude that : 1-the nominal axial tension force strength for the cross section is greater that the nominal axial compression force strength in specified depth variables d1 & d2. this is due to the material properties for the steel which is included empirically in the equation pg the nominal strength. 2-the flexural moment strength for the section decreases with increasing the depth variable d1 but it is increases with increasing the depth variable d2. this is because that the flexural moment strength equation depends basically on the depth variable d2. 3-the strength constrain function is slightly affected by the design variable d1 but it is strongly affected by the design variable d2. optimality criteria for depth variables al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 115 it is shown previously that displacement and strength constraints in addition to the objective function of the optimum design problem considered is highly nonlinear function of design variables. the optimality criteria approach was found to be an effective method in finding the solution of such design problem (1, 5and 8).this technique transformation the constrained problem into an unconstrained one by using lagrange multipliers. the lagrangian of design problem is: ),(.),(),,,( 21 1 21 11 21 iisti nm i sriiidj j dji nm i isridjii ddgddgvddl ∑∑∑ === ++= λλρλλ ρ (36) where djλ and sriλ are the lagrange multipliers for the displacement and strength constraints respectively . the necessary condition for the local constraint optimum is obtained by differentiating this equation with respect to design variables (d1 d2 as the follows: 0 ),( . ),(),,,( 1 21 11 21 1111 21 = ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ ∑∑∑ === i iisti nm i sri i iidj j dj i nm i i i sridjii d ddg d ddg d vi d ddl λλρ λλ ρ (37) 0 ),( . ),(),,,( 2 21 12 21 1212 = ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ ∑∑∑ === i iisti nm i sri i iidj j dj i i nm i i i sridjji d ddg d ddg d v d ddl λλρ λλ ρ (38) the derivative of the volume of tapered member with respect to depth variables can analytically obtained as follows : iw ii wffi lt dd tbtv ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ + +−= ) 2 )( )(2 21 (39) iw i i i i lt d v d v . 2 1 21 = ∂ ∂ = ∂ ∂ (40) the derivative of the displacement constraint from eq. (11) becomes: i j i iidj dd ddg 11 21 ),( ∂ ∂ = ∂ ∂ δ (41) i j i iidj dd ddg 22 21 ),( ∂ ∂ = ∂ ∂ δ (42) which in turn from eq. (12) becomes: ij i iii nm i t i i j x d ddk x d 1 21 11 ),( ∂ ∂ = ∂ ∂ ∑ = δ (43) ij i iii nm i t i i j x d ddk x d 2 21 12 ),( ∂ ∂ = ∂ ∂ ∑ = δ (44) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 116 the derivatives of stiffness matrix of the tapered member can be achieved analytically in ref.(3 ). on the other hand the , the same can also be achieved for the derivative of the strength constraints with respect to design variables(d1 , d2) as follows: n i n n i n i iisri m d ma p d pa d ddg 2 1 1 2 1 1 1 21 )()(),( ∂ ∂ − ∂ ∂ −= ∂ ∂ (45) n i n n i n i iisri m d ma p d pa d ddg 2 2 2 2 2 1 2 21 )()(),( ∂ ∂ − ∂ ∂ −= ∂ ∂ (46) the derivatives )( j n d p ∂ ∂ and )( j n d m ∂ ∂ can be achieved using numerical technique (finite difference technique) as follows; 1121 12 11 ii nn i n i n dd pp d p d p − − = ∆ ∆ = ∂ ∂ , 1121 12 11 ii nn i n i n dd mm d m d m − − = ∆ ∆ = ∂ ∂ (47) 1222 12 22 ii nn i n i n dd pp d p d p − − = ∆ ∆ = ∂ ∂ , 1222 12 12 ii nn i n i n dd mm d m d m − − = ∆ ∆ = ∂ ∂ (48) hence the optimality criteria for depth variables are obtained from equation (37) and (38) as follows: 0) )()( ( ),(),,,( 2 1 1 2 1 1 11 21 11111 21 = ∂ ∂ − ∂ ∂ −×+ ∂ ∂ ×+ ∂ ∂ = ∂ ∂ ∑∑∑∑ ==== n i n n i n nm i sriji i iii nm i t i j dj ii i nm i i i sridj m d ma p d pa x d ddk x d v d ddl λλρ λλ ρ (49) which lead to: ∑ ∑∑∑ = === ∂ ∂ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ − ∂ ∂ −×+ ∂ ∂ × − nm i i i i n i n n i n nm i sriji i iii nm i t i j dj d v m d ma p d pa x d ddk x 1 1 2 1 1 2 1 1 11 21 11 ) )()( ( ),( ρ λλ ρ and 0) )()( ( ),(),,,( 2 2 2 2 2 1 12 22 11212 21 = ∂ ∂ − ∂ ∂ −×+ ∂ ∂ ×+ ∂ ∂ = ∂ ∂ ∑∑∑∑ ==== n i n n i n nm i sriij i iii nm i t i j dj i i nm i i i sridj m d ma p d pa x d ddk x d v d ddl λλρ λλ ρ (51) which lead to: 1 ) )()( ( ),( 1 2 2 2 2 2 2 1 12 21 11 = ∂ ∂ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ − ∂ ∂ −×+ ∂ ∂ × − ∑ ∑∑∑ = === nm i i i i n i n n i n nm i sriij i iii nm i t i j dj d v m d ma p d pa x d ddk x ρ λλ ρ =1 (50) (52) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 117 multiplying both sides of equations (52) and (54) by dc1i and dc 2 i , respectively, and then taking the cth root yields: ×=+ i tt i dd 1 1 1 c t nm i i i i n i n n i n nm i sriji i iii nm i t i j dj d v m d ma p d pa x d ddk x 1 1 1 2 1 1 2 1 1 11 11 11 ) )()( ( ),( ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ − ∂ ∂ −×+ ∂ ∂ × − ∑ ∑∑∑ = === ρ λλ ρ ×=+ t i t i dd 2 1 2 c t nm i i i i n i n n i n nm i sriij i iii nm i t i j dj d v m d ma p d pa x d ddk x 1 1 2 2 2 2 2 2 1 12 21 11 ) )()( ( ),( ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ − ∂ ∂ −×+ ∂ ∂ × − ∑ ∑∑∑ = === ρ λλ ρ where t and t+1 represent the current and the following optimum design cycles, and the c is known as the step size process. it is apparent that the use of equation. (53) and (54) require that values of lagrange multipliers to be known .there are several methods to obtain their values .one simple and effective way used in ref.(1).this method takes the constraint equality and multiplies both sides by m djλ and then takes the mth root .this leads to the following recursive relationship : m ju jr j r dj 1 1 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ⋅= + δ δ λλ j=1, 2,eq. ρ (55) where m is the step size and its value form the numerical examples is between 0.8 and 0.7 for m 1 .it is clear that eqs. (54) and (55) require the initial values of the lagrange parameters to be selected .it was found suitable to use (10000) as an initial value for these parameters (multipliers). figures (8) and (9) shows the relationships between the derivatives of the strength constraints with the design variables d1 & d2 . from these figures we can conclude that : 1-for the value of 2.0< n u p p , the derivative of strength constraints for the cross section is slightly greater in compression that in the tension force with respect to design variables d1 & d2. 2for the value of 2.0≥ n u p p the derivative of strength constraints for the cross section is slightly greater in tension that in the compression force with respect to design variables d1 . (53) (54) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 118 nonlinear elastic analysis of steel frames composed of tapered members. the nonlinear elastic analysis of frames composed from tapered members is obtained by the method reported in ref.(3) .this method improved from the nonlinear elastic analysis of frames composed of prismatic members described in ref.(7) which takes into account both the geometrical and material nonlinearities . design convergence criteria: two types of design criteria are use in this study to insurance the satisfaction of the convergence in design, these are : 1-weigh criteria: this criterion depends on comparison of the weight of the frame for the current design cycle and the weight of the frame for the previous design cycle, and convergence is assumed to have occurred when the inequality : 12 2 1 tolw ww r rr ≤−+ )( is satisfied (56) where: wr+1: represents the total weight of the structure in the current design cycle wr : represents the total weight of the structure in previous design cycle 2-depth criteria :this criterion depends on comparison of the depth at both ends of each design group of the frame for the current design cycle and for the previous design cycle, and convergence is assumed to have occurred when the inequality when the inequality 21 )( tolddd ttt ≤−+ (57) in eq. (56 ) and (57 ), the dimensionless quantity, tol. represents a prescribed tolerance each criteria in this study the tolerance used as indication for satisfied the convergence is as follows tol1= 0.005. tol2= .01 flow chart and computer program: the algorithm developed for optimum design of geometrical nonlinear elastic –frame composed of tapered members can be described by the following chart of the program with a brief description for each subroutine, fig.(10) and a computer program (edts) is developed using qbasic language. . design examples two examples are used her to demonstrate the capability of the algorithm developed in this study to achieve the optimum design of tapered steel frame under elastic nonlinear behavior , the values of modulus of elasticity and yield strength of the steel used to fabricate the structure were taken as 205 kn/mm2 and 275n/mm2 respectively .the density of the steel was 7850kg/m3.th convergence criteria used for the minimum objective function was 0.1% while it was 1% for the depth variables 1-fixed ends tapered beam. in this example a single span beam was designed using the algorithm developed in this study , the dimensions of the beam ,member cross section and loading condition is shows in fig. (11) the beam was divided into two linearly tapered beams which introduced two design variables in each beam (1,2)in beam no.1 and (2,3)in beam no.2 , due to symmetry the depths and nodes 1 & 3 was assumed to be the same . this would eliminate the design variables into two variables (d1& d2), the frames was designed under three cases of constraints 1-displacement constraints 2-strength constraints. 3-both displacements & strength constraints. the results of both studies is shown in figs.(12 to14) it shows from these figures that the reduction in depth variable d2 is more faster than in depth variable d1 which mean that the value of depth variable d2 more effective in the optimum design processes from the value of d1 this may be caused by the including of the geometrical nonlinearity in the analysis and taking in the account the large deformation, bowing effect and stability behavior of the structure which lead to increasing the al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 119 effect of design components relating to depth variable d2 on the other hand the depth variable d2 usually used in maximum flexural moment zone which is usually near the support so that the deformations and displacement is being at their maximum value and then cause that increase in optimum design components. from figures (12-14) we can note that when excluding the displacement constraints from the optimum design processes the decreasing in depth variables d1 & d2 become more that when using both displacements and strength constraints and which lead to lighter structure and subsequently more economic and more save in cost without increase in the constrained displacement on its upper bound. this mean that including the strength constraints in the optimum design processes will improve the design efficiently. on the other hand the optimum design reached after design cycle no.8 we using strength constraints only in the optimum design comparing with design cycle no.9 when including both displacement and strength constraints. 2-pitched roof tapered steel frame. in the example a one bay pitch roof frame is designed using the optimum design algorithm developed her, the frame is divided to 15 node at the point of application the external loads and 14 tapered member , the dimension of the frame ,member cross section and loading condition is shows in fig.(15 ). this frame was designed by ref. (5 ) using linear elastic analysis , in this study the frame is designed three constraints cases : 1-displacement constraints 2-strength constraints. 3-both displacements & strength constraints. the results of our study is shown in figures (16 to 19) , from these figures we reach to the same view obtained from the previous example in addition to noting that in this example we have two deign groups the rafters (beams ) and the columns , each group treated separately in design processes but at the joins the developed program takes into account the effect of changing in each depth variable on the connected members which help in giving more reliable design .t he results of design for each group are shown separately in figures ( 16 ) and ( 17 ) we can note the similarity in behavior for each group . the effect of nonlinear analysis is shown obviously in fig.( 19 ) hence from this figure we can observe that the displacement reached to its upper limit faster than the former example. conclusions: depending on the design results obtained from the present study, one can draw several conclusions, concerning the optimum design of the tapered steel frames with i –section these may be summarized as follows: 1-the optimum design components represented in this study by the strength and displacement constraints equations is affected by the design variable d2, specially when including the geometrical nonlinearity and stability behaviors in the analysis of steel frame. this is required to choose the value of depth variable d2 carefully in design of such frames. 2the excluding of displacement constraints in the optimum design processes( using strength constraints only )lead to faster design and more economic and saving in cost design . 3-in frames composed from different structural members, the behavior of the optimum design results will be slightly different. 4this study may be improved by including more restrains in to design processes that make the design more economic and more saving in time and cost such as (buckling constraint, plasticity constraint, creep constraint) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 120 tf tw bf d2 d1 l tw bf tf references fig. (1): typical tapered member with linear variation 1hayalioglu, m. s. and saka, m. p.,” optimum design of geometrically nonlinear elasticplastic steel frames with tapered members”, inter. jour. of compu. and struc. vol.44, no.4,1992, pp.915-924. 2haitham a. bady, " nonlinear elastic-plastic instability analysis of frames with nonprismatic members", msc. thesis, university of technology/building and construction department, 2000. 3-haitham a. bady," optimum design of nonlinear elastic-plastic steel frames composed from non-prismatic members with displacement constraints"", jour. of babylon university, vol. 13, no.5, 2005. 4-load and resisting factored design ,specification for structural steel build, aisc, u.s.a, 2000. 5m.p.saka," optimum design of steel frame with tapered members" j. computer &structures, vol.63, no.4, pp.797-811, 1997. 6-m.p.saka."optimum design of steel frames with stability constraints" j. computer & structures, vol.41, pp.1365-1277, 1991. 7oran, c., “geometric nonlinearity in nonprismatic members”, jour. of the stru. div., asce, vol. 100, no. st7, july, 1974, pp.1473-1487. 8raphael.t.haftka and zfer gurdal "element structural optimizations" , solid mechanics and its applications , mkluwer academic puplishers,1993 9-tam, t. k. h. and jennings, a., “optimal elastic design of frames with tapered members” , inter. jour. of computers and structures, vol. 30, no.3, 1988, pp.537-544. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 121 fig.(2): relationship between design variables d1 & d2 and the nominal flexural strength mn 400 600 800 1000 1200 1400 design variables d1,d2 (mm) 8e+8 1e+9 1e+9 1e+9 2e+9 2e+9 n om in al f le ct ur al s tr en gt h (k n .m ) d1 d2 400 600 800 1000 1200 1400 design variables d1,d2 (mm) 2e+6 3e+6 3e+6 4e+6 4e+6 5e+6 5e+6 n om in al a ix al f or ce s tr en gt h (n ) d1, compression force d2, compression force d1, tension force d2, tension force fig.(3): relationship between design variables d1 & d2 and the nominal axial force strength pn 500 700 900400 600 800 1000 design variables d1 (mm) 1500 2500 3500 1000 2000 3000 4000 d er iv at iv e of a xi al f or ce s tr en gt h w ith r es pe ct to d 1 d1, compression d1, tension 500 700 900 1100 1300400 600 800 1000 1200 1400 design variables d1, d2 (mm) -5e+5 5e+5 2e+6 3e+6 4e+6 -1e+6 0e+0 1e+6 2e+6 3e+6 4e+6 d er iv at iv e of f le ct ur al m om en t s tr en gt h w ith r es pe ct to d 1, d 2 d1, tension ,compression d2, tension ,compression 400 600 800 1000 1200 1400 design variables d1,d2 (mm) 0.55 0.65 0.75 0.85 0.95 0.50 0.60 0.70 0.80 0.90 1.00 s tr en gt h c on st ra in ts d1,compression d2, compression d1,tension d2,tension pu/pn>=0.2 400 600 800 1000 1200 1400 design variables d1,d2 (mm) 0.50 0.70 0.90 0.40 0.60 0.80 1.00 s tr en gt h c on st ra in ts d1,compression d2, compression d1,tension d2,tension pu/pn<0.2 fig.(4): relationship between design variable d1 and the derivatives of nominal axial force strength pn with respect to d1 fig.(5): relationship between design variables d1 & d2 and the derivatives of nominal flexural strength mn with respect to d1&d2 fig.(6): relationship between design variable d1 and the strength constraints fig.(7): relationship between design variable d1 and the strength constraints al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 122 fig.(9): relationship between design variable d1 &d2 and the derivatives of strength constraints in the case of compression force fig.(8): relationship between design variable d1 &d2 and the derivatives of strength constraints in the case of tension force 400 600 800 1000 1200 1400 design variables d1,d2 (mm) -0.00 -0.00 -0.00 -0.00 -0.00 -2.5e-3 -2.0e-3 -1.5e-3 -1.0e-3 -5.0e-4 0.0e+0 d er iv at iv e of s tr en gt h c on st ra in ts d1,tension, pu/pn >=0.2 d2, tension, pu/pn>= 0.2 d1, tension, pu/pn < 0.2 d2, tension, pu/pn < 0.2 400 600 800 1000 1200 1400 design variables d1,d2 (mm) -0.00 -0.00 -0.00 -0.00 0.00 -2.0e-3 -1.5e-3 -1.0e-3 -5.0e-4 0.0e+0 5.0e-4 d er iv at iv e of s tr en gt h c on st ra in ts d1,compression, pu/pn <0.2 d2, compression, pu/pn <0.2 d1, compression, pu/pn >=0.2 d2, compression, pu/pn >=0.2 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 123 select initial values of design variables (d1,d2 ) and other sectional properties for each group in addition to the geometrical and material properties for each member. select the initial values of the design components (lagrange multiplier, step size, constraints displacements, tolerance, upper bound displacement , )carry out the nonlinear elastic analysis of the frame and calculate the displacement vector [xi] carry out the linear elastic analysis of the steel frame using the original coordinates of the frame due to a unite load and then obtain the joint displacement vector [xij] of eq.(12 ). optimum design cycles tt dd ,1+ compare these values with their lower bound , take whichever greater as a new values of depth variables i-1 to ng ng=number of design groups in frame no yes continue equal compare set the design variables equal to their lower bound weight convergence yes no print the results start select design parameters nonlinear linear calculate all the components of eqs. (55) & (56) and the new values of lagrange multipliers using eq. ( 57 ). determine the new values of design variables (d1,d2) for each group in the frame using eqs.(55 ) and (56 ). calculate the new weight of the frame ,cheak the convergence of both weights an depths , if it is obtain , terminate the design and printout the results otherwise go to the next step fig. (10) flow chart of the computer program (edts) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 124 fig.(11): fixed ends tapered beam. fig.(13):relationships between the iteration cycles and constrained displacement 1 3 5 7 90 2 4 6 8 10 iteration cycle 0.75 0.85 0.95 1.05 0.70 0.80 0.90 1.00 1.10 to ta l w ie gh t e 8 (k g) displacement and strength con. displacement con. only strength con. only 1 3 5 7 90 2 4 6 8 10 iteration cycle 300 500 700 900 200 400 600 800 d es ig n v ar ia bl es d 1& d 2 (m m ) design variables d1,both displacement and strength con d2,both displacement and strength con d1, displacement con. only d2, displacement con. only d1, strength con. only d1, strength con. only 0 2 4 6 8 iteration cycle 2 6 10 0 4 8 12 c on st ra in te d d is pl ac em en t( m m ) both displacement and strength con displacement con.only strength con.only fig.(12):relationships between the iteration cycles and the design variables d1 &d2 fig.(14):-relationships between the iteration cycles and total weight of the beam al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 125 fig(15): pitched roof fixed ends steel frame . ` 1 3 5 70 2 4 6 8 iteration cycle 500 700 900 400 600 800 1000 d ep th v ar ia bl es d 1 & d 2 d2 , displacemet and strength constraints d1 , displacemet and strength constraints d2 , strength constraint only d1 , strength constraint only group (1) 1 3 5 70 2 4 6 8 iteration cycle 500 700 900 400 600 800 1000 d ep th v ar ia bl es d 1 & d 2 group (2) fig.(16):relationships between the iteration cycles and depth variables d1&d2 for rafters fig.(17):relationships between the iteration cycles and depth variables d1&d2 d2 for columns 1 3 5 70 2 4 6 8 iteration cycle 5.300 5.500 5.700 5.900 5.200 5.400 5.600 5.800 6.000 to ta l s tr uc tu re w ei gh t gruop (1) gruop (2) 1 3 5 70 2 4 6 8 iteration cycle 38 42 46 50 54 36 40 44 48 52 56 c on st ra in te d d is pl ac em en t (m m ) displacemnt and strength constraints strength constraint only fig.(18):relationships between the iteration cycles and total weight of the frame fig.(19):relationships between the iteration cycles and the constrained displacements microsoft word 6 nomographs for design of two input transmissions using fuzzy logic in matlab al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 59 design of two input transmission using fuzzy logic in matlab essam lauibi esmail lecturer college of engineering/university of qadisyah abstract this work presents proposed design of a parallel hybrid transmission with only one electric motor/generator (mg) and without any rotating clutches. the proposed motor/generator integrated hybrid transmission serves to regulate the engine's effective gear ratio (engine rotational velocity versus vehicle velocity) by mixing the engine and electric mg powers through a power controlling device. the proposed design provides some of the benefits and flexibility of a power-split design but using conventional available components in a simpler mechanical layout that makes the design compact, mechanically simple, and operationally flexible. with a control unit, four major modes of operation excluding a regenerative braking capability are shown to be feasible in the proposed hybrid transmission; electric motor mode, engine mode, engine/charge mode, and power modes. continuously variable transmission (cvt) capability is provided with the engine/charge mode and with the power mode. the power mode can be further subdivided into three hybrid sub-modes that correspond to the direct drive, under-drive, and over-drive of a conventional automatic transmission. the feasibility of the proposed hybrid transmission is demonstrated with a numerical example employing a simple gear train. in this work a controller is designed to vary the speed of the vehicle for different driving conditions. all basic driving conditions for a car are studied and identified. the new controller is implemented by using fuzzy logic and simulated in matlab/ simulink. keywords: fuzzy logic, matlab, mechanisms, nomograph, planetary gear trains, simulink, two inputs, transmission. ق الغامض في برنامج الماتالبطنقل حركه ثنائية المدخل بأستخدام المن ةتصميم آلي كلية الهندسه/جامعة القادسيه/مدرس/ عصام العيبي إسماعيل الخالصه مولــد كهربــائي واحــد ودون أي قــوابض /ذا البحــث تصــميم جديــد آلليــة نقــل حركــه هجينــه بأســتخدام محــركھيقــّدم السـرعه الدورانيـه للمحـرك مقابـل سـرعه (جديد على تنظـيم النسـبه السـرعيه الفعالـه للمحـرك يعمل التصميم ال. دواره يقـدم التصـميم . المولد الكهربائي خالل وحـدة تنظـيم القـدره/بخلط قدرتي ماكنة االحتراق الداخلي والمحرك) العربه ليديــه متاحــه بتركيــب ميكــانيكي المقتــرح بعــض فوائــد ومرونــة التصــميم الشــاطر للقــدره ولكــن بأســتخدام مكونــات تق بوجـــود وحـــدة ســـيطرة ، وآلليـــه نقـــل الحركـــه ". بســـيط ، يجعـــل التصـــميم مـــدمجا ، بســـيط ميكانيكيـــا، ومـــرن تشـــغيليا االيقـاف بتوليـد الكهربـاء وهـي طـور المحـرك الهجينه المقترحه هناك أربعة أطـوار رئيسـيه ممكنـه عمليـا عـدا طـور al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 60 المولــد الكهربــائي وطــور القــدرة /اق الــداخلي ، طــور ماكنــة االحتــراق الــداخلي الكهربــائي فقــط ، طــور ماكنــة االحتــر أن الحصــول علــى آليــة نقــل حركــه ذات أمكانيــه لتغييــر الســرعه ). المحــرك الكهربــائي/ماكنــة االحتــراق الــداخلي ( ويمكـن تقسـيم . المولد الكهربائي الثاني وفي طور القدرة /بصوره مستمره ممكن في طور ماكنة االحتراق الداخلي طــور القــدره الثــاني الــى ثــالث أطــوار ثانويــه هــي مــا دون ومــا فــوق القيــاده المباشــره والقيــاده المباشــره التــي تنــاظر .مثيالتها في أآلليات اآلليه التقليديه .تم التحقق من أمكانية أستخدام اآلليه الهجينه المقترحه بمثال عددي وبأستخدام مجموعة ترسيه كوكبيـه بسـيطه وتـم تشـخيص جميـع ظـروف قيـادة السـياره . وتم تصميم مسيطر لتغيير سرعة العجله فـي ظـروف القيـاده المختلفـه وقـــــد تـــــم تضـــــمين المســـــيطر باســـــتخدام المنطـــــق الضـــــبابي ومحاكاتهـــــا فـــــي االساســـــيه والتصـــــميم علـــــى ضـــــوءها matlab/simulink).( nomenclature mbω the rotational loss torque of the system. c clutch egm epicyclic gear mechanism egt epicyclic gear train ess nergy storage system ُ◌ e flc fuzzy logic controller hev hybrid electric vehicle ffm ikk .= ma ee / a constant, which is also the ratio mg electric motor/generator xpn , gear ratio defined by a planet gear p with respect to a sun or ring gear x. xpxp zzn /, ±= , where pz and xz denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative signs depend on whether x is a ring or sun gear. owc one way clutch pgt planetary gear train cr reverse clutch soc state of charge ths toyota hybrid system two-dof two-degree of freedom zi number of teeth on gear i c carrier s sun gear r ring gear p planet gear iω angular velocity of link i aaqa rl /=τ the electrical time constant of the armature. bjm /=τ the mechanical time constant of the system. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 61 introduction and literature review a hybrid system combines two motive power sources, such as an internal combustion engine and an electric motor, to achieve efficient driving performance. a hybrid electric vehicle (hev) achieves fuel economy, and improved performance by combining a smaller than normal engine with electric motor(s) and an energy storage system (ess). the engine is smaller in displacement, or downsized, so that the average loads that the vehicle has to meet during acceleration and highway driving are closer to the engine's higher efficiency operating zones, represented by the 30% efficiency in figure 1 [1]. a hev uses the electric motors and ess to average the load on the engine, to achieve an efficient use of fuel. one or two electric motors are used in a variety of ways, depending on how they are connected to the vehicle power train [2]. motors can provide a positive torque to drive the vehicle alone in the forward or reverse direction, or assist the engine during acceleration. one way to increase the average load and decrease fuel use is to shut off the engine when the vehicle load is small. commonly this is referred to as engine idle stop, but the engine can sometimes be kept off for light accelerations and low cruising velocities. peak power demands on the engine, such as a hard acceleration, can be lowered by using the motors to supply some of the additional power required, and discharge the batteries. under conditions in which motors demand negative torque, they operate as generators to recharge the batteries. by acting as a generator, the electric motor increases the average load on the engine. numerous hev configurations have been proposed. john miller's book [1] is a good resource for more information about hybrid vehicles and hybrid systems. in the present work, only hevs with epicyclic-type power trains will be considered. tsai and schultz [3], proposed an improved design of the novel parallel hybrid transmission introduced earlier by tsai et al. [4, 5]. the proposed design provides the transmission the functional appearance of a conventional 4-speed ratio change automatic transmission. the design needs a motor/generator unit with a conventional automatic transmission to function; therefore it requires more complicated controllers and extra electronics hardware than with other hybrids. tsai [6] proposed an innovative approach using just one internal combustion (ic) engine, one electric motor/generator, and a power regulating gearbox that can provide a vehicle with six different operating modes including a regenerative braking capability. recently esmail [7] proposed new designs of parallel hybrid transmissions with only one electric motor/generator (mg) and without any rotating clutches. toyota hybrid system (ths) [2], which is a series/parallel hybrid, contains a power split devise that splits power into two paths. in one path, the power from the engine is directly transmitted to the vehicle's wheels. in the other path (electrical path), the power from the engine is converted into electricity by a generator to drive an electric motor or to charge the battery. since the engine is the primary converter on the vehicle, the direct fuel to engine to wheels path is the most efficient energy path on the vehicle. ths posses many favourable characteristics; however the potential disadvantages of ths design include the need for two electrical motors and a constant split of the engine power. also, the simultaneous dual motor operation requires sophisticated control systems and intricate custom fabrication [8]. electric machines are used to generate mechanical work in industries. the dc machine is considered to be basic electric machine. the aim of this work is to use computer simulation as a tool for conducting transient and control studies. next to having an actual system to experiment on, simulation is often chosen by engineers to test conceptual designs [9]. simulink is the program used to complete the modelling and simulation of a model; it is a subprogram of matlab. in simulink, a model is a collection of blocks which, in general, represents a system. matlab/simulink is used because of the short learning term that most students require to start using it, its wide distribution, and its general-purpose nature. this will al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 62 demonstrate the advantages of using matlab for analyzing system steady state behaviour and its capabilities for simulating transients in systems, including control system dynamic behaviour [10]. this work presents a new design of a hybrid transmission with only one electric motor/generator and without any clutches. any epicyclic gear set is considered adaptable to suit the new design of the hybrid transmission. for the kinematic analysis of epicyclic gear mechanisms (egms) various approaches have been proposed. in this work the new developed nomograph method [11] will be used. nomographs a nomograph is defined as three or more axes, or scales, arranged such that problems of three or more variables can be solved using a straightedge. in the particular case of egts, a nomograph can be constructed using three or more vertical parallel axes [11 and 12]. a basic egt consists of sun gear, ring gear, planet, and carrier as shown in figure 2. figure 3 shows the basic form of the graph to be created for a basic egt. the term "gear ratio" is used in this paper to denote the ratio of a meshing gear pair. it is defined by a planet gear p with respect to a sun or ring gear x xpxp zzn m=, (1) where zp and zx denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative sign depends on whether x is a ring or sun gear. considering the kinematics of a fundamental circuit, the fundamental circuit equation can be written as buchsbaum and freudenstein [13]: xpcpcx n ,)()( =−− ωωωω (2) equation (2) can be re-written for the links of the basic egt to find cpppsprp nandnnn ,,,, ,, . these values are used to place the axes of the nomograph shown in figure 3. the cω axis passes at the origin, and the pω axis is one unit apart from it. the gear ratios for this train are rprp zzn =, (3) and spsp zzn −=, (4) from figure 3 the characteristic equation can be written as follows: sprp rp sr cr nn n ,, , − = − − ωω ωω (5) the number of teeth of ring gear is 71, the number of teeth of planet gear is 16 and the number of teeth of sun gear is 39. by substituting these values in equations3, 4 and 5 the following equation is obtained 0.35427+ 0.64566 = rc sωωω (6) conceptal design and modelling of the hybrid transmission the new hybrid transmission system consists of an engine and an electric motor/generator coupled together by a simple gear train in such a way that both of the engine and electric motor/generator al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 63 can simultaneously provide torque to the wheels. figure 4 shows the new hybrid transmission system. the electric motor/generator can function as a motor to add torque to or as a generator to subtract torque from that produced by the engine. the electric generator regulates the speed of the vehicle by varying its loading so that the engine can be operated at a constant speed. figure 5 shows the block diagram of the new hybrid system. the engine serves as one power source and the battery as the second power source. the motor/generator can receive power from the battery to drive the vehicle or take power from the engine to charge the battery depending on the driving condition. a power controlling epicyclic gear train (pc egt) is used to control the power flow among the engine, the motor/generator and the vehicle, so that the vehicle can operate in several different modes. these modes are shown schematically in figures 6, 7, 8 and 9. operation modes 1. electric motor mode when first started, the vehicle begins to operate using the motor unless the battery state of charge (soc) is low. the one-way clutch (owc) is engaged and the electric motor alone drives the vehicle in the forward direction. to drive the vehicle in the reverse direction, the reverse clutch is engaged and the motor rotates in the opposite direction. the electric motor alone drives the vehicle in the forward or reverse direction to avoid low load engine operation in which the engine experiences poor efficiency. the electric motor is used to lunch the vehicle from a standstill and for driving in city traffic. 2. engine/charge or first cvt mode once the engine has started, mg begins generating electricity, or adding power depending on the power demand and the battery soc. when both of the demand for power and soc are low with mg functioning as a generator part of the engine power is directed to the wheels and the other part goes to the electric mg for charging the batteries. these conditions force the egt to function as a power splitting; one-input and two-output device. part of the engine power is directed to the wheels and the other part goes to the electric mg for charging the batteries. the ratio of these two powers is continuously variable. therefore, it is possible to run the engine at optimal operating conditions while regulating the load of the output shaft by controlling the load of the generator. also, for a given output power, it is possible to run the engine at an optimal operating efficiency point by controlling the load of the generator. figure 10 shows the nomograph for this mode with the upper and lower limits of the generator velocities for certain engine velocity. from this figure, we can easily visualize that the engine can operate at any desired velocity while the velocity of the vehicle is regulated by controlling the generator velocity. when all of the engine power is converted to electric power then the engine is idling and the vehicle is stationary. when mg is stationary the mode is the engine mode. 3. engine mode during steady-state highway cruising and when the battery soc is high to handle accessory loads, the transmission can operate in the engine mode. the battery supplies mg with current to generate sufficient torque to lock it in place. the engine alone drives the vehicle in the forward direction, electricity generation is basically not necessary. 4. power or second cvt mode at moderate and high vehicle velocities with mg functioning as a motor, both the electric motor and the engine drive the vehicle simultaneously in a power mode [14]. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 64 there are three cases: • when both of the motor and engine rotate at the same velocity, the gear set locks up as a rigid body. a hybrid mode that corresponds to the direct drive of a conventional automatic transmission except for the fact that both of the electric motor and engine transmit their power to the output shaft with a one-to-one gear ratio. • at moderate vehicle velocities, the motor rotates slower than the engine; both of them drive the vehicle in an under-drive. • at high vehicle velocities, the motor rotates faster than the engine; both of them drive the vehicle in an over-drive. from figure 11 by regulating the amount of the motor power (by varying its rotational velocity), the motor allows the engine to operate at an optimal condition. in this regard the egt functions as a cvt. in another words, the engine can be operated at any desired velocity while the velocity of the vehicle is regulated by the electric motor. motor modelling and simulation to perform the simulation of a system, an appropriate model needs to be established. for this work, the system contains a dc motor. therefore, a model based on the motor specifications needs to be obtained. dc machines are one of the most commonly used machines for electromechanical energy conversion. converters are used continuously to convert electrical input to mechanical output or vice versa. they are called electric machines. an electric machine is therefore a link between an electrical system and a mechanical system. in these machines, the conversion is reversible. if the conversion is from mechanical to electrical, the machine is said to act as a generator. if the conversion is from electrical to mechanical, the machine is said to act as a motor. therefore, the same electric machine can be made to operate as a generator as well as a motor [9]. dc machines may also work as brakes. the brake mode is a generator action but with the electrical power either regenerated or dissipated within the machine system, thus developing a mechanical braking effect. it also converts some electrical or mechanical energy to heat, but this is undesired. the major advantages of dc machines are easy speed and torque regulation. the major parts of any machine are the stationary component, the stator, and the rotating component, the rotor. assuming magnetic linearity [9], the basic motor equations are amaff ikiikt ... == (7) mmmff kike ωω ... == (8) the laplace transforms of equations (7) and (8) are )()( . sams ikt = (9) )(. smma ke ω= (10) let the switch sw be closed at t = 0. after the switch is closed, dt di lirev aaqaaat ++= (11) from equation (8) and (11) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 65 dt di lirkv aaqaammt ++= ω. (12) the laplace transform of equation (12) for zero initial conditions is )()()()( ... saaqsaasmmst islirkv ++= ω (13) or )1.(.. )()()( asaasmmst sirkv τω ++= (14) the dynamic equation for the mechanical system is represents the rotational loss torque of the system lm m am tb dt d jikt ++== ω ω .. (15) the laplace transform of equation (15) is )()()()()( ... slsmsmsams tbsjikt ++== ωω (16) from equation (15) and (16) )1()/.1( )()()()( )( m slsamsls sm sb tik bjsb tt τ ω + − = + − = (17) from equation (16) and (17), ).1().1( )()()()( )( aa smmst aa sast sa sr kv sr ev i τ ω τ + − = + − = (18) a block diagram representation of equation (1 7) and (1 8) is shown in figure 13. this block diagram can be simplified and implemented in simulink and the model window shown in figure 14 should appear; where aarl τ.= and mbj τ.= . for dc motor and as given by reference [15], the following parameters are used: j=0.01 n.m.s^2/rad b=0.1 km=10 n.m/a (engine-motor constant) km=8 n.m/a (dc-motor constant) r=1 ohm l=0.5 f load =0.001 n.m the engine is simulated as a motor in the operational block diagram of the speed control system. intelligent controller design the intelligent speed control system should be designed to provide smooth ride and robustness of the system to varying operating conditions [15 and 16]. in this work a controller has been designed to vary the speed of the vehicle for different driving conditions. the block diagram identifying all necessary functional relations between the controller and other subsystems of the mobile is shown in figure 15. the controller is used as an interface between the vehicle driver and two power sources, ic engine and dc motor. driver controls the vehicle by pressing accelerator/decelerator pedal. the controller responds to the driver commands and selects an optimal driving condition for the car vehicle mixing intelligently the energies from the two power sources by means of epicyclic al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 66 gear train. the feedback loop is used additionally to monitor the actual speed of the dc motor. all basic driving conditions for the car have been identified as follows: i) vehicle idling -engine runs, car is still stationary, pedal is untouched. ii) vehicle accelerates – accelerator pedal is being pressed to some extent. iii) vehicle runs with constant speed – no change in position of the accelerator pedal. iv)vehicle decelerates –pedal is being pressed to less extent. v) vehicle stops – pedal has been released. vi) vehicle reverses – reverse switch is on, accelerator is being pressed. the new controller is implemented by using fuzzy logic and simulated in matlab/simulink. the operational block diagram of the speed control system is shown in figure 16. the default settings are used when running fuzzy logic. the apparent success of fuzzy logic controller (flc) can be attributed to its ability to incorporate expert information and generate control surfaces whose shapes can be individually manipulated for different regions of the spaces with virtually no effects on neighbouring regions. flc is ideal for the velocity control problems, since there is no complete mathematical model of the engine and other components of the car [17]. however, some human driving experience and visual feedback can be used in the design of control system as well [18–23]. human operators control the velocity of the car by pressing the accelerator pedal. from these human actions, fuzzy rules were formulated using the amount and the rate at which the accelerator and decelerator pedal is pressed [24–26]. the membership functions to represent the inputs and the outputs of flc are symmetric triangles with equal distribution over the entire range or the universe of discourse. for example, the input values to the controller from the accelerator/decelerator pedal are divided into ten membership functions to describe pedal position in terms of generation or taking electricity, the negative sign refers to the generation of electricity and the positive sign refers to absorbing electricity from batteries. they are ‘very high generation’, ‘high generation’, ‘medium generation’, ‘low generation’, ‘very low generation’ ‘very low motor’, ‘low motor’, ‘medium motor’, ‘high motor’, ‘very high motor’. similar functions are developed for the feedback velocity. in the design of the controller the output is presented in the form of voltage signal. therefore, the output membership functions are named as ‘very high negative voltage’, ‘high negative voltage’, ‘medium negative voltage’, ‘low negative voltage’ , ‘very low negative voltage’, ‘very low positive voltage’, ‘low positive voltage’, ‘medium positive voltage’, ‘high positive voltage’ , ‘very high positive voltage’. there are total of 100 rules formulated for the controller design using mamdani implications. simulation results in order to test the performance of the designed controller, the matlab software and its fuzzy logic toolbox (v7.6.0.320) is used. the toolbox provides a friendly graphical user interface (gui), which makes the testing faster and more efficient. 1. power mode the first step in testing the controller is to generate an operator signal for testing. figure 17 shows a motor/generator signal that begins to work at second two as a motor till the eight second. the response of the motor is shown in blue and that for the engine is shown in yellow. the total speed of the vehicle is shown in purple colour in figure 18. the engine is energized and picking up the speed until it begins to rotate in a constant velocity. the dc motor is still off till the time when it begins to pick up speed. the results of simulation are shown in figure 18 and figure19, for power mode in which the vehicle accelerate, run with constant velocity or decelerate. 2. engine/charge mode and power mode figure 20 shows another motor/generator signal that begins to work as generator, then after second two it begins to work as a motor till the eight second. the response of the motor is shown in blue al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 67 and that for the engine is shown in yellow. the total speed of the vehicle is shown in purple colour in figure 21. the engine is energized and picking up the speed until it begins to rotate in a constant velocity. the dc motor is still off till second two when it begins to pick up speed. the results of simulation are shown in figure 21 and figure 22 for a power mode in which the vehicle accelerate, run with constant velocity or decelerate. conclusion this work successfully introduces a new hybrid transmission design for hybrid vehicles recently immerged in automotive industry. the system does not require a physical braking subsystem which will reduce the overall cost of a car. the paper presents a new control approach in driving a vehicle. the controller is built on the speed mixing capability of a two degree of freedom epicyclic gear train. signals from the accelerator/decelerator pedal and reverse button are intelligently treated in flc to generate input signals for two driving actuators – car engine and additional dc motor. they, in turn, jointly control the speed of vehicle wheels according to the characteristic equation of the selected epicyclic gear train. this work illustrates the simulation results of basic driving conditions of a car, such as engine idling, car acceleration, deceleration, stop, and reverse. references [1]miller, j.m.,"propulsion systems for hybrid vehicles", london, the institution of electrical engineering, 2004. [2]toyota motor corporation, http: // www.toyota.co.jp/en, printed in japan in march 2007 on recycled paper pr-e-07bc02. [3]tsai, l. w., and schultz, g.,"a motor-integrated parallel hybrid transmission", journal of mechanical design, 126(5), pp. 889-894, 2004. [4]tsai, l. w., schultz, g. , higuchi, n., "a novel parallel hybrid transmission", journal of mechanical design, 123(2), pp. 161-168, 2001. [5]schultz, g., tsai, l.w., higuchi, n., and tong, i.c.,"development of a novel parallel hybrid transmission", sae transactions, journal of passenger cars mechanical systems, paper no. 2001-01-0875, 2001; also in sae special publications on transmission & driveline systems, sp1598. [6]tsai, l.w., "design of a power regulating gearbox for parallel hybrid electric vehicles", proceedings of the 4th national conference on applied mechanisms and robotics, cincinnati, oh, paper no. amr-95-052, 1995. [7] esmail, e.l., " hybrid transmission for mobile robot", accepted for publication in the journal of mechanical design, asme, 2011. [8]boyd, s.j., "hybrid electric vehicle control strategy based on power loss calculations", m. sc. thesis, department of mechanical engineering , virginia polytechnic institute and state university , blacksburg , va ,usa, 2006. [9] m. h. nehrir, f. fatehi, and v. gerez, "computer modeling for enhancing instruction of electric machinery, " ieee trans. educ., vol. 38, pp. 166–170, may 1995. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 68 [10] uriuhara, m., hattori., t., and morida, s., (1988). "development of automatic cruising using fuzzy control systems", journal sae japan, vol. 42, pp. 224-229. [11]esmail, e.l., "kinematic nomographs of epicyclic-type transmission mechanisms", emirates journal for engineering research, volume 12, issue 3, pp. 47-55, 2007. [12]esmail, e. l. "nomographs for enumeration of clutching sequences associated with epicyclic type automatic transmission mechanisms", asme international mechanical engineering congress and exposition (imece08), october 31november 6, 2008 boston, massachusetts, usa, paper no.66409, 2008. [13]buchsbaum, f., and freudenstein, f.,"synthesis of kinematic structure of geared kinematic chains and other mechanisms", journal of mechanisms and machine theory, 5, pp. 357-392, 1970. [14]esmail, e. l., and hassan, s. s., 2008, "torque and power-flow analysis of two input epicyclic-type transmission trains," asme international mechanical engineering congress and exposition (imece08), october 31-novembere 6, 2008 boston, massachusetts, usa, paper no.imece2008-66377, 17, transportation systems, pp.155-164. [15]nazim, m. n., and hussaini, s., “new intelligent transmission concept for hybrid mobile robot speed control,” int. j. of advanced robotic systems, vol. 2, no. 3, pp. 259–263, 2005. [16]nazim, n. m. and salami m.j.e, "design of intelligent multi-finger robotic gripper using slip detection technique", proc. world engineering congress (wec'99), pp. 17-21, 1999. [17] abate m., and dosio, n.,"use of fuzzy logic for engine idle speed control", sae tech. paper #900594, 1990. [18] ball., j. t.,"approaches and trends in automatic speed controls", sae tech. paper # 670195, 1967. [19] chaudhure, b., schwabel, r. j., voclkle, l. h.,"speed control integrated into the power train computer", sae tech. paper # 860480, 1986. [20]follmer, w. c.,"electronic speed control", sae tech. paper # 740022, 1974. [21]hong g., and collins, n., "application of self-tuning control," sae tech. paper #900593, 1990. [22]liubakka, m., k., winkelman, j., r., kokotovich, p., v. (1993). "adaptive automotive speed control, ieee transactions on automatic control", vol. 38, no. 7, july 1993, pp. 10111020 [23]nakamura, k., ochiai, t., and tanigawa, k., "application of microprocessor to cruise control system." proceedings iee, workshop on automotive applications of microprocessors, pp.37-44, 1982. [24] sobolak, s. j.,"simulation of the ford vehicle speed control system", sae tech. paper 3820777, 1982. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 69 [25]tabe t., takeuchi, h., tsujii m., and ohba, m., "vehicle speed control system using modern control theory", proceedings 1986 international conference on industrial electronics, control and instrumentation, iecon’86, vol. 1, pp. 365-370, 1986. [26] tsujii, t., takeuchi, h., oda., k., and ohba, m.,"application of self-tuning to automotive cruise control", proceedings of american control conference, pp 1843-1848,1990. figure 1 typical engine efficiency map [1]. figure 2 a basic epicyclic gear train. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 70 figure 3 nomograph for the basic epicyclic gear train [8]. figure 4 the new hybrid transmission system. figure 5 block diagram of the new hybrid system. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 71 figure 6 electric motor mode. figure 7 engine/charge mode. figure 8 engine mode. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 72 figure 9 power mode. figure 10 nomograph for the engine and engine-charge modes of the new hybrid transmission. figure 11 nomograph for the power mode of the new hybrid transmission. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 73 figure 12: schematic diagram of a dc motor figure 13 block diagram representation of a dc motor. figure 14 block diagram representation of a dc motor in simulink. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 74 figure 15 functional interrelations between subsystems. figure 16 operational block diagram of the speed control system. figure 17 a motor/generator signal. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 75 figure 18 response of the motor, engine and vehicle. figure 19 simulation results for acceleration, deceleration or cruising of the car. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 76 figure 20 a motor/generator signal. figure 21 response of motor, engine and vehicle. figure 22 simulation results for idling, acceleration, deceleration or cruising of the car. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 579 shear behavior of hybrid reinforced concrete beams assist.lec. aamer najim abbas college of engineering/al-mustansiriya university/civil engineering department abstract this study present experimental investigation on shear behavior of hybrid rectangular cross section reinforced concrete beams strengthened with high strength concrete on compression zone of beams. the experimental work contain six specimens, three with normal strength concrete at all section and others contain high strength concrete in compression zone. the effect of inclusion layer of high strength concrete on shear strength, ductility, deflection and cracking load are studied in this investigation. experimental results showed that the ultimate shear strength, ductility deflection and cracking load are increased when used high strength concrete in compression zone. key words : shear, hybrid, high strength concrete سلوك القص للعتبات الخرسانية الهجينة عامر نجم عباس: المدرس المساعد قسم الهندسة المدنية/الجامعة المستنصرية/كلية الهندسة الخالصة تقدم هذه الدراسة بحثاً عملياً لسلوك القص للعتبات الخرسانية المسلحة ذات مقطع مستطيل المقواة بالخرسانة عالية .ة االنضغاطالمقاومة في منطق ثالثة منها تحوي خرسانة عادية المقاومة في كل المقطع والثالثة االخرى تحوي , يتضمن الجزء المختبري ستة نماذج .خرسانة عالية المقاومة في منطقة االنضغاط al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 580 ل التشقق تمت دراسته في التشوهات وحم, المطيلية, تأثير استخدام طبقة من الخرسانة عالية المقاومة على مقاومة القص .هذا البحث اظهرت النتائج المختبرية بان هناك زيادة في مقاومة القص والمطيلية والهطول وكذلك حمل التشقق عندما استخدمت الخرسانة .عالية المقاومة في منطقة االنضغاط introduction to increase the load carrying requirement of steel sections, a hybrid section is used. the concept of hybrid section in steel structures is not a new idea. salmon and johnson (1) defined a hybrid girder as one that has either the tension flange or both flanges of steel section made with a higher strength grade of steel than used for the web. for steel fiber reinforced concrete sections, kawamata et al.(2) defined a hybrid fiber reinforced concrete as a composite material which contains two different types of fiber together. the hybrid matrix (concrete) containing the steel fibers becomes more ductile and the tensile strength due to crack arrest mechanisms of steel fibers is much improved. ali(3) make an experimental and theoretical investigation of flexural and shear behavior of hybrid i-shaped cross section reinforced concrete beams strengthened with steel fibers and/or high strength concrete (hsc), and cast with or without construction joints. also sahib(4) make an experimental study on beam which contain high strength concrete and normal strength concrete in one beam and study effect the layer of high strength concrete on flexural behavior, strain and ductility. in order to repair or strengthen structural elements, layers of new concrete are often applied to an old structure. hence, bernard, et al.(5) defined hybrid concrete structures as structural elements consisting of new and old concrete layers. when extending the hybrid concept to composite concrete members and due to advances in concrete technology, it is relatively easy to produce composite sections which possess high compressive strength, high ductility, high energy absorption and high tensile strength at the same time. these characteristics can be achieved by placing two or more different types or strengths of concrete layers together so that each layer is used to its best advantage and as a result, the concrete section becomes a "hybrid" section. in the present study, the hybrid rectangular shape cross section beam is defined as one that has either the compression zone made with high strength concrete different from that used for the tension zone. high strength concrete the relatively recent development in concrete technology has led to produce high compressive strength concrete of (50 to 150 mpa). high strength concrete can be produced by adding high range water-reducing admixtures (superplasticizers) and/or other admixtures (silica fume or fly ash) to portland cement concrete. superplasticizer compounds sharply reduce the amount of water required al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 581 to produce a workable mix so that concretes with water cement ratios on the order of (0.25) or less flow easily without excessive bleeding and segregation. the use of high strength concrete in construction leads to the design of smaller sections; reduction of dead weight, and allowance of longer spans and more usable area of buildings. although high strength concrete offers advantages in terms of performance and economy of construction, the brittle behavior of the material remains a major drawback in some structural applications especially in earthquake resistant structures. since strength and ductility of concrete are inversely proportional, high strength concrete is significantly more brittle than the normal strength concrete(6). shear in reinforced concrete beams shear failure in reinforced concrete members are sudden and catastrophic in nature and should be avoided in the design process. that is why reinforced concrete members are first dimensioned in flexure and then checked out for shear. the effect of shear is to induce tensile stresses on inclined plans oriented at approximately 45o to the plane on which the shear stresses act. failure occurs when these stresses, along with horizontal stresses due to bending, exceed the diagonal tensile strength of the material. therefore, shear failures in concrete members are diagonal tension phenomena; the failures occur in an inclined plane due to the combined effect of shear and flexural stresses. however, it is difficult to determine the value of the diagonal tension stresses in reinforced concrete beam because the distribution of shear and flexural stresses over a cross section is not known with certainty (reinforced concrete is a composite, non homogeneous and nonisotropic material that cracks significantly under relatively low loads). accordingly, shear strength prediction in reinforced concrete members is an empirical problem based on the assumption that a shear failure at the critical section occurs on a vertical plane when the fictitious shear stresses at that section, , exceed the concrete fictitious vertical shear strength ( also called nominal shear strength). that are basically two definitions for the nominal shear strength: the ultimate shear strength , , and the cracking shear strength, . the cracking shear strength is defined as the shear strength at the occurrence of a first major diagonal crack; the ultimate shear strength is defined as the shear strength when complete and total failure occurs(7). according to aci 318-2008(8) design procedure, it is useful to know the shear carrying capacity of beams reinforced in bending only before the addition of web reinforcement. if the shear at the critical shear is greater than one-half the nominal shear resistance, then stirrups are added to carry the difference. therefore, the shear strength prediction of reinforced concrete members without web reinforcement is an important piece of information in the design process of concrete beams and frames. furthermore, there are many concrete structural members such as slabs, walls and foundations that do not use stirrups, and consequently, a good knowledge of the shear strength of reinforced concrete members without web reinforcement is also necessary in these cases. there are several factors effect shear strength of beams: beam size: the shear strength increase with increasing beam dimension(9). longitudinal reinforcement: as the longitudinal reinforcement decrease there is reduction in beam shear strength(9). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 582 shear span to depth ratio: the shear strength decreases dramatically as the shear span to depth ration increase in case of short beam(10). concrete compressive strength: there increase in shear strength when increasing the compressive strength of concrete. experimental investigation six beams were tested in an experimental investigation conducted at al-mustansiriya university the primary variable influencing the specimen design was layer of high strength concrete which added to the upper side of beam in compression zone. the experimental program was divided in to three separate test series. series (1) was comprised of two beams designed flexural reinforcement over ρmin and 3ø5 in each side as a shear reinforcement and the dimension of these beams (100x200x1000mm). series (2) was comprised of two beams designed flexural reinforcement over ρmin and 5ø5 in each side as a shear reinforcement and the dimension of these beams (100x200x1000mm). series (3) was comprised of two beams designed flexural reinforcement over ρmin and 7ø5 in each side as a shear reinforcement and the dimension of these beams (100x200x1000mm). see figures (1,2,3) and table (1). materials cement the type of cement used in this study is ordinary portland cement (type i). fine aggregate fine aggregate used in this study, has a maximum size less than (5 mm). coarse aggregate the ideal coarse aggregate should be clean. with large amount of crushed aggregate and a minimum of flat and elongated particles is used. steel reinforcement the reinforcing steel is deformed .the average yield strength is (435mpa), the average ultimate strength is (601 mpa), and the reinforcing steel bar is (10 and 12 mm) in diameter for compression and tension respectively. this test is made in the materials laboratory, college of engineering, almustansiriya university. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 583 mix proportions table (2) show the mix proportions is used in tested beams. compressive strength cylindrical (150x300) and cubical (150x150) specimens were used to test the compressive strength of concrete. the compressive test was done according to astm c39 and b.s 1881 by using a computerized machine in the materials laboratory, college of engineering, al-mustansiriya university, with a capacity of (1000 kn). the cylindrical and cubical compressive strength is shown in table (3). testing machine the machine which was used in the tests is a universal hydraulic machine with (300 ton) capacity . the loading arrangement is shown in figure (4) and figure (5). cracks pattern and general behavior the mode of failure as expected was typical shear failure in all tested beams. see figure (6) to figure (11). cracking of each specimen progressed as follow; flexural cracks at mid-span developed during the early stages of loading. additional flexural cracks along the shear span as load increased. these cracks gradually became inclined as the propagated along the longitudinal reinforcement continue to the support. in general, the type of concrete in compression zone greatly affects the observed cracking pattern. in beams hs3, hs5 and hs7 with high strength concrete in compression zone have shear cracks wider than the shear cracks in ns3, ns5 and ns7 with no high strength concrete in compression zone this may be due to the high compressive strength in hs3, hs5 and hs7 beams. ultimate shear strength the ultimate shear strength of the tested beams are compared with the reference beams (ns3, ns5 and ns7) and reported in the table (4) in terms of shear force at failure (vu). the strength of beams (hs3, hs5 and hs7) with high strength concrete in compression zone was increased (10.8, 13.7 and 11.1 )% this due to increase in compressive strength, beam stiffness and improved the resistance to the tensile cracking in the compression zone and as a result, the overall strength of the beam was increased. load-deflection behavior in general, there are three stages in load-deflection curve, these stages are cracking load, yielding load and ultimate load capacity. at first stage, beams cracks in flexure under small load, first crack is observed at load ranging from (10-18)% of the ultimate load. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 584 in precracking stage, deflection increase linearly in all beams with loading this means that the materials in compression and tension zone are in elastic manner. in postcracking stage there is also linear relationship between load and deflection but with different slope up to yielding of longitudinal reinforcement after that there is a curvature in loaddeflection curve up to failure by shear. in general the deflection of beams (hs3, hs5 and hs7) (which contain high strength concrete in compression zone) more than the reference specimens (ns3, ns5 and ns7) at same loading values, and the maximum deflection at failure in specimens which contain high strength concrete in compression zone is more than the maximum deflection in beams had not high strength concrete in compression zone. see figure (12) to figure (14). ductility ductility is defined as the energy absorbed by the material until complete failure occurs and equal to the deflection at ultimate load to the deflection at yielding. as shown in table (5), at beams (hs3, hs5 and hs7) the ductility was increased (47.9, 97,3 and 46.85)% respectively in comparison with beams (ns3, ns5 and ns7) which had not high strength concrete in compression zone, this is because slight increase in ultimate load capacity, which produce higher ultimate deflection, also this is may be due to the construction joint between high and normal strength concrete which decreased the beam stiffness then increased ultimate deflection and ductility. in general, all tested beams exhibited good ductility due to presence high strength concrete in compression zone and presence of construction joint. first cracking load the first cracking loads are shown in table (4). for all beams, the first cracking were distributed in the moment region, the visible first cracking loads of the beams are between (10.25%) and (18.3%) with respect to the ultimate loads. for beams cast with high strength concrete in compression zone (hs3, hs5 and hs7) the cracking load that produced first cracking about (15.38%, 20.46%, 12.3%) in comparison with beams without high strength concrete in compression zone (ns3, ns5 and ns7) respectively. this increase may be due to the resistance remaining in the tension zone. the experimental values of cracking loads are obtained from measuring the load-deflection diagram. table (6) shows a comparison between measured and predicted values of cracking load according to aci 318-02 code. t gr cr y if m . = … (1) pcr = l mcr 6* … (2) where: mcr = cracking moment, n.mm al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 585 pcr = cracking load; n ƒr = modulus of rupture of concrete, n/mm2. ig = moment of inertia of gross concrete section about centroidal axis, mm4 yt = distance from centroidal axis of gross-section to extreme fiber in tension l = distance between two supports; mm comparing the experimentally measured values and those calculated according to eq. (2), it can be seen, that all the estimated values are within an accuracy of about (33%, 34%, 33%, 34.8%, 27.5%, 24.3) for ns3, hs3, ns5, hs5, ns7 and hs7 respectively. conclusions 1. the beams with high strength concrete in compression zone have shear cracks wider than the shear cracks in beams with no high strength concrete in compression zone. 2. the beams with high strength concrete in compression zone have ultimate shear strength higher than the beams which have no high strength concrete in compression zone. 3. the deflection in beams with high strength concrete in compression zone is more than the deflection in beams with no high strength concrete in compression zone. 4. the maximum deflection at failure in beams with high strength concrete in compression zone is more than the maximum deflection in beams with no high strength concrete in compression zone. 5. there is good improvement in ductility in beams with high strength concrete in compression zone. 6. the cracking load in beams with high strength concrete in compression zone is greater than the cracking load in beams with no high strength concrete in compression zone. references 1. salmon, c. g., and johnson, j. e., "steel structures: design and behavior" 3rd edition, harper collins publishers inc., usa 1990, (1086) p. 2. kawamata, a., mihashi, h., and fukuyama, h., "properties of hybrid fiber reinforced cement-based composites", journal of advanced concrete technology, japan concrete institute, vol. (1), no. (3), november 2003, pp. 283-290. 3. ali, h., a, " flexural and shear behavior of hybrid i-beams with high-stength concrete and steel fibers ", doctoral thesis, al-mustansiriya university, 2006. 4. shatha, s., k, " flexural bhavior of hybrid reinforced concrete beams ", m.sc thesis, al-musansiriya university, 2006. 5. bernard, o., mivelaz, p., and brühwiler, e., "investigation of the long term behavior of hybrid concrete structures", 2nd international ph.d symposium in civil engineering, budapest, 1998, pp. 1-8. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 586 6. ashour, s. a., and wafa, f. f., “flexural behavior of high strength fiber reinforced concrete beams”, aci structural journal, vol. (90), no. (3), may-june 1993, pp. 279287. 7. karim, s. rebeis, “ shear strength prediction for concrete members”, aci structural journal, vol.124, no.3, march, 1999, pp301-308. 8. aci code(318-2008),” building code requirements for reinforced concrete”, american concrete institute, detroit, 2008. 9. eric, j. tomas and robert ,j. frosch,” influence of beam size, longitudinal reinforcement, and stirrups effectiveness on concrete shear strength”, aci structural journal, vol.99, no.5, march, 2003. 10. karim s. rebeis, javier fente and michael a.frabizz,” effect of variables on shear strength of concrete beam”, journal of materials in civil engineering, vol.13, no.6, nov.-dec.,2001. table (1) specimens specifications type of section compressive strength group no. specimens normal reinforced concrete hybrid reinforced concrete flexural reinforcement shear reinforcement normal concrete high strength concrete ns3 / 2ø12 down 2 ø10 up 3ø5 36 g1 hs3 / 2ø12 down 2 ø10 up 3ø5 36 51.3 ns5 / 2ø12 down 2 ø10 up 5ø5 33.15 g2 hs5 / 2ø12 down 2 ø10 up 5ø5 33.15 49.3 ns7 / 2ø12 down 2 ø10 up 7ø5 31.8 g3 hs7 / 2ø12 down 2 ø10 up 7ø5 31.8 54 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 587 table (2) mix proportions concrete strength mpa cement kg/m3 sand kg/m3 gravel kg/m3 water kg/m3 w/c ratio sp ltr/m3 27 415 535 1250 183 0.44 80 541 774 984 151 0.28 7 table (3) compressive strength of tested beams specimens cube strength cuf (mpa) cylinder strength cf ′ (mpa) ns3 36 27.13 normal strength 36 27.13 hs3 high strength 51.3 40.3 ns5 33.15 24.93 normal strength 33.15 24.93 hs5 high strength 49.3 38.65 ns7 31.8 23.1 normal strength 31.8 23.1 hs7 high strength 54 42.82 table (4) ultimate shear strength of tested beams specimens ultimate shear strength percent of increase in ultimate load ns3 74 ــــــــ hs3 82 10.8 ns5 102 ــــــــ hs5 116 13.7 ns7 117 ــــــــ hs7 130 11.1 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 588 table (5) ductility index of tested beams beam no. ultimate deflection(δu) (mm) yielding deflection(δy) (mm) ductility index( ) % increase in ductility ns3 3.3 1.98 1.67 ــــــــــــ hs3 3.52 1.42 2.47 47.9 ns5 4.3 2.82 1.52 ــــــــــــ hs5 5.1 1.7 3 97.3 ns7 3.05 2.13 1.43 ــــــــــــ hs7 5.45 2.6 2.1 46.85 table (6) cracking load beam no. experimental cracking loads (kn) theoretical cracking loads (kn) %increase in experimental cracking load % ns3 13 8.7 33 ـــــــــــــ hs3 15 9.9 15.38 34 ns5 13 8.7 33 ـــــــــــــ hs5 15.66 10.2 20.46 34.8 ns7 12 8.7 27.5 ـــــــــــــ hs7 14.75 11.16 22.9 24.3 figure (1) series (1) figure (2) series (2) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 589 figure (3) series (3) figure (4) test set-up figure (5) testing machine al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 590 figure (6) crack pattern and failure mode of beam ns3 figure (7) crack pattern and failure mode of beam hs3 figure (8) crack pattern and failure mode of beam ns5 figure (9) crack pattern and failure mode of beam hs5 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 591 figure (10) crack pattern and failure mode of beam ns7 figure (11) crack pattern and failure mode of beam ns7 figure (12) load-deflection curve of specimens (ns3 and hs3) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 592 figure (13) load-deflection curve of specimens (ns5 and hs5) figure (14) load-deflection curve of specimens (ns7 and hs7) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 77 electrolytic preparation of copper powder with particle size less than 63µm ali h. abbar mechanical engineering department college of engineering, al-qadisiyia university abstract an electrochemical cell consisting of two electrodes (lead-6%antimony alloy cathode and copper anode, (99.9%)) was used to study the electrolytic preparation of copper powder with particle size less than (63µm) directly as powdery form. copper sulphate dissolved in sulfuric acid solution was used as electrolyte. the produced powder was thoroughly washed with an acidified distilled water and absolute ethanol, then dried under an inert atmosphere at 80oc, and classified by screening. samples of prepared powder were taken to determine their purity by atomic absorption. the effects of current density, metal ion concentration, sulfuric acid concentration, and electrolysis time on the weight percent of copper powder less than (63µm), yield and current efficiency were studied. it was found that copper powder with particle size less than (63µm) can be prepared at a weight percent (79.7% ) and current efficiency( 75%) using cathode current density (0.16 a/cm2),copper ion concentration(5gm/l),sulfuric acid concentration(100gm/l)temperature(25-30oc)and electrolysis time equal to(2hr). the prepared powder having an apparent density (2.24 gm/cm3) and specific surface area (421 x 103 cm2/gm). its average particle size was (42 µm) and its purity was (99.7%) . keywords: copper powder, electrolytic copper, electrodeposition of copper, electrolytic preparation )63µm(التحضير الكهروكيميائي لمسحوق النحاس بحجم حبيببي اقل من الميكانيكية قسم الهندسه علي حسين عبار جامعة القادسيه -كلية الهندسه الخالصه مون واألخر انودي انتي%6-تم استخدام خليه آهروآيميائيه مؤلفه من قطبين احداهما آاثودي مصنوع من سبيكه رصاص المسحوق الناتج .تم استخدام الكتروليت من آبريتات النحاس مذابه في حامض الكبريتيك ) .%99.9(مصنوع من النحاس ذو نقاوة تبع ذلك تصنيفه حسب )80oc(تم غسله جيدا بماء محمض ومقطر ومن ثم باأليثانول ثم تجفيفه تحت جو خامل بدرجة حراره تم دراسة تاثير آل من آثافة .خذ نماذج من المسحوق المحضر وحددت نقاوته باستخدام تقنية األمتصاص الذري تم ا .الحجم الحبيبي ترآيز حامض الكبريتيك وزمن التحلل الكهربائي على النسبه الوزنيه للمسحوق الناتج ذو الحجم الحبيبي ,ترآيز ايون النحاس ,التيار بنسبه ) 63µm(وجد انه باألمكان تحضير مسحوق النحاس ذو الحجم الحبيبي األقل من ياروآفائة الت ,األنتاجيه, )63µm(األقل من مذابه ) gm/l 5(النحاس وترآيز ايونات )a/cm2 0.16(عند استخدام آثافة تيار )%75(وآفائة تيار ) %79.7(وزنيه التقل عن اوإجراء ) /l 100gm (في حامض الكبريتيك ذو ترآيز .2hr(زمن تحلل ب) 30oc-25(ي بدرجة حرارهئ عملية التحلل اآهرب x 103 421(و ذو مساحه سطحيه نوعيه ) gm/cm3 2.24(المسحوق المحضر عند هذه الظروف آانت آثافته الظاهريه ). cm2/gm ( ومعدل حجم حبيبي)42 µm( ونقاوه)99.7% ( . 32 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 33 introduction copper powders have been used in industrial applications for many years. probably the best known is the self-lubricating bearing which was the first major application and still accounts for about 70% of the copper powder used (dunkely,2002). this application takes advantage of the ability to produce a component with controlled interconnected and surface-connected porosity. the production of metallic filters also takes advantage of this ability. pure copper powder is used in the electrical and the electronics industries because of its excellent electrical and thermal conductivities. copper in powder form is used in structural parts and friction materials. brasses, bronzes and other copper alloys produced by powder metallurgy methods have the physical and mechanical properties of their cast or wrought counterparts. copper is used also as an alloying element in iron powder components to enhance the mechanical properties and control dimensional changes during sintering, the addition being made either by mixing or by infiltration. in addition to the above applications of copper powder, a large quantity of copper and copper alloy powder is used in flake form, i.e., as a powder whose thickness is small in relation to its other dimensions. such powders are used, for example, in antifouling paints, decorative and protective coatings, and printing inks. copper powders are also used in such nonstructural applications as brazing, cold soldering, and mechanical plating, as well as for medals and medallions, metal-plastic decorative products and a variety of chemical and medical purposes (german.,1994). copper powder can be produced by a number of methods, the most important being atomization, electrolysis, hydrometallurgy and solid state reduction. each method yields a powder having certain inherent characteristics (kirk-othmer,1991).in atomization process, copper is melted and the liquid metal flows through an orifice where it is struck by a high velocity stream of gas or liquid, usually water, thus breaking the molten metal into particles which solidify rapidly. particle size and shape are influenced particularly by the atomizing medium, pressure and the flow rate. controlled small additions of deoxidizing elements, such as phosphorus, also influence the particle size and shape (4). the hydrometallurgy process can be used to produce copper powder from cement copper, concentrates or scrap copper. the copper is leached from these materials with sulfuric acid or ammoniacal solutions and the pregnant solution is separated from the residue by filtration. the copper is precipitated from solution by reduction with hydrogen under pressure. in one process, for example, reduction is accomplished in an autoclave at 225-280°f (107-138°c) in one hour under a partial pressure of hydrogen of 400 psig (total pressure 425 psig) with a thickening agent added to minimize plating and control the particle size. during reduction, 90-95% of the copper is precipitated as powder. the powder is pumped as slurry to a centrifuge where the powder is separated from the liquid and washed. the wet copper powder is dried in a reducing atmosphere, milled, classified and blended to achieve the desired particle size distribution. the physical characteristics of the powder can be varied over a considerable range. temperature, time of reduction and the quantity of acrysol addition have a marked influence on the powder properties (5). in solid state reduction method, oxides including mill scale are first ground to control particle size and then reduced by a gas, usually carbon monoxide, and hydrogen or cracked natural gas at temperatures below the melting point of copper. particle size and shape can be controlled within rather wide limits by varying the particle size, shape of the oxides, reducing temperature, pressure and flow of the gas (rutledge,1975). the electrolytic method is probably the most economical method for producing cooper powder; moreover the copper powder obtained is the highest quality .the electrolytic powder consists of particles whose dimensions and form (dendritic shape) which can be well pressed and sintered. besides, in recent years it has been shown that by different electrolysis regimes it is possible not only to obtain powders with a wide range of properties, but to predict the decisive al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 34 characteristics of powders that are of vital importance for powder quality and for the final application. the major advantage of electrolytic method over the other methods lies in the possibility of conducting the process under conditions such that powders of a wide range of volumetric mass are obtained (0.4 4.0 gm/cm3).electrolytic copper powder is produced by following principles used in electroplating with the conditions changed to produce a loose powdery deposit rather than a smooth adherently solid layer. the techniques for electrodepositing of copper powder have advanced in two directions: electrodeposition of fragile deposits, which by grinding yield powders and electrodeposition of powder directly. several parameters influence the characteristic and structure of copper powder produced as well as the yield and current efficiency which play an important role on the economy of the process .these are :metal ion concentration ,current density ,agitation ,temperature, conductivity of electrolyte and added colloids to solution. current density and metal ion concentration are more pronounced on the yield and current efficiency (calusaru,1979). table (1) shows the typical properties of copper powder produced by various methods electrodeposition of copper powder dates back to 1920 when leach and henry used a bath of copper sulphate and sulfuric acid without additives (b.leach and henry,french,1920).formation of copper powder by electrodeposition has been examined on a laboratory scale by drumill where high apparent density (2.7gm/cm 3 ) obtained using acid sulphate bathes(drumiller ,moulton,1920) .the first serious attempt to produce electrolytic copper in quantities was in 1959, when the metal was deposited at a current density of (0.05-0.5 a/cm2) at 30oc and an average voltage of the cell(2.3volt)( mantell,1959) .enchevl used reversing current for copper powder preparation by electrolytic extraction where high purity of powder was obtained(99.99%), (enchevl, kharizanov, 1974).ralph used electrolytic method for making high density copper powder starting with copper powder of lower apparent density in this method, an integral two-phase process is provided in which copper powder of relatively lower apparent density is formed by electrodeposition, and the powder so-formed is then used in a second phase electrodeposition process as a cathode on which copper powder of the desired relatively high apparent density is formed (rippere, 1976).later on a method of producing copper powder is provided that uses electrolytic cuprous oxides as the starting material for production copper powder suitable for a conductive filler. this method is developed instead of the well known methods that used electrolytic copper powder obtained as compact deposits ( yamada, hirata,2006). the aim of the present research is to prepare an electrolytic copper powder directly in powdery form rather than compact deposits to be suitable for conductive filler. experimental work the copper powder electrodeposition was carried out at constant current operation during the electrolysis (galvanostatically) using a 3.5-liter capacity electrolytic cell (made of perspex) having provision for electrode adjustment in all required directions as shown in fig. (1). the dimensions of the cell were (18x32x6 cm) having a top coversheet. the cell consisting of two electrodes: cathode plate made of (lead-6%antimony alloy)with dimensions(30x16cm),and anode made of copper plate with dimensions(30x16cm),having a purity not less than (99.9%).an enter electrode distance of (3cm) was maintained to minimize the current losses due to solution resistance .the effective surface area of cathode (immersed area)suitable for applying the limited current density was determined by moving vertically the cathode up or down the level of the electrolyte the two electrodes were first subjected to mechanical treatment with first rough and fine emery paper, kept in dichloroethane in order to remove any grease from the electrode surface, shaken in distilled water for a few minutes and wiped with drying paper before being placed in the cell. a power supply (20 ampere, 30 volt) was used to driven the circuit, currents (8-30 amperes) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 35 were applied through the experiments and the electrolysis was proceded at room temperature. all the reagents used for preparing the electrolyte were of analytically grade (merck) and did not undergo further purification .distilled and deionized water was used in preparing the solutions. a 2.5-liter electrolyte was prepared for each run by dissolving copper sulphate(99.9%) in sulfuric acid solutions(25-150gm/l). the amount of copper ion in the electrolyte at the starting and during the electrolysis was determined by using atomic absorption technique (shemadzo-2100 at the laboratories of ibnsina state company /ministry of industry/iraq). at the end of each run , copper powder was scraped out the cathode , washed with distilled water (luke-warm and acidified , ph=2 ) and absolute ethanol , dried under nitrogen atmosphere at 80oc, screened using (63 µm ) sieve and weighted the two cuts (upper and lower than 63µm ) . samples of the prepared powder were taken to determine their purity by atomic absorption. the cathode in turn was rinsed in dilute sulfuric acid and made ready for subsequent use. factorial experimental design was used to study the effect of the main parameters on the percent of powder having particle size less than (63µm), current efficiency and yield. results and discussion the effects of the main parameters were studied in order to determine the preferred conditions for obtaining copper powder directly in powdery form at higher percent of particle size less than (63µm) with a suitable current efficiency. 1-current density: figures (2, 3, and 4) show the effect of current density (0.06-0.25a/cm2) on the percent of copper powder less than (63µm), current efficiency and yield respectively. it can be seen that the percent of copper powder and yield increase with increasing the current density while the current efficiency decreases. this is because of the increasing in the rate of hydrogen evolution as current density increases leading to increase the penetration and distribution of hydrogen bubbles through the bed of copper powder formed on the cathode surface which make the particles of copper finer. it is to be noted that current efficiency drops down (60%) as the current density reaches (0.2 a/cm2) .from practical view point, it is not recommended that the current efficiency reduces lower than 60% because of a high electrical energy will be lost and to avoid excessive heating of the electrolyte, formation of dendritic-tree growths on the cathode and to maintain a useful electrolytic deposition rate. in addition, the temperature of the electrolyte reached to (50 oc) at current density (0.2 a/cm2) as observed in the experiments. the temperature increasing led to increasing the copper ion concentration in the electrolyte higher than 50%of the initial value (5gm/l) . therefore current density (0.16a/cm2) be suitable for copper powder preparation in powdery form in which current efficiency higher than 65%could be obtained and copper ion concentration increasing during the electrolysis not higher than 5%of the initial value. 2-copper ion concentration figures (5, 6, and 7) show the effect of copper ion concentration (3-25gm/l) on the percent of copper powder less than (63µm), current efficiency and yield respectively. in this case ,both the percent of copper powder less than (63µm) and yield increase with decreasing the copper ion concentration while the current efficiency decreases .this can be interpreted as that the mass transfer of copper ions decreases as the concentration decreases leading to increase the electrode potential where the rate of hydrogen evolution will be increased. figure (6) shows that the current efficiency drops lower than (70%) as the copper ion concentration lowers than (5 gm /l). therefore ,it is preferred to operate at concentration of copper ion close or equal to(5gm/l )to insure the current efficiency being higher than (70%)and maintaining the percent of copper iron powder less than (63µm) as high as possible with a reasonable yield. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 36 3-sulfuric acid concentration figures (8, 9, and 10) show the effect of sulfuric acid concentration (25-150gm/l) on the percent of copper powder less than (63µm), current efficiency and yield respectively. it is observed that any increasing in sulfuric acid concentration leads to increasing the percent of copper powder less than (63µm) and yield with decreasing the current efficiency, however the effect is not critical as those in the current density and copper ion concentration. it was observed that current efficiency drops lower than 68% when sulfuric acid concentration became higher than 100gm/l.therefore it is preferred to maintain the concentration of acid on or below this value. 4-time of electrolysis: the effect of electrolysis time (0.5-5hr.) on the percent of copper powder less than (63µm), current efficiency and yield are given in figures (11, 12, and 13). these figures show that each of weight percent of powder less than (63 µm), and yield decrease with increasing time of electrolysis while the current efficiency increased. this is because of the increasing in the effective surface area of the cathode as time increases, so that current density will be lowered. accordingly, it is not preferred to operate at time higher than (2 hr.) since the percent of copper powder less than(63 µm) lowered than (60%).from technical standpoint, the powder must be removed periodically after (2 hr) to insure high percent of powder less than 106µm at reasonable current efficiency. the preferred conditions the preferred conditions for preparing copper powder directly in powdery form are summarized in table (2). a run was achieved under these conditions, the results indicate that a weight percent of copper powder less than (63 µm ) equal to(80%) can be obtained with reasonable current efficiency (75%) ,the powder obtained having the analysis shown in table(3)which is acceptable from industrial point view to be used as conductive filler(13). conclusion 1the electrodeposition of copper powder with particle size less than (63 µm) directly in powdery form can be achieved by an electrochemical cell consisting of cathode made from lead6%antimony and anode made from copper(99.9%)with applying the following operating conditions: cathode current density (0.16 a/cm2) copper ion concentration (5 gm/l) sulfuric acid concentration (100gm/l ) time of electrolysis per batch (2 hr.) temperature (25-30oc) 2it was found that the powder obtained according to above conditions has a weight percent of particle size less than (63µm) close to 80% and an average particle size (42 µm) .this result is a promoting step for the economy of the present work . 3if we considered the additional step of milling required in the production of copper powder as a compact deposit, and the cheap of electrical energy in the case of the energy producing countries( petroleum countries).the prepared powder could be used as a conductive fillers since the level impurities lower than the standard level. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 37 references 1. dunkely, j. , 2002, "market overview, epri center of materials production, usa, industry segment profile-sic 33991. 2. german, r.m. 1994, "powder metallurgy science ",2nd edition ,metal powder industries federation, princeton, new jarsy. 3. kirk-othmer, 1991, "encyclopedia of chemical technology", 4rd edition, wily intersience pub., new york, vol.7, p. 206-208. 4. k.r.suttill, 1990, eng.min.j.,191,30. 5. hass and o.weir, 1983, "hydrometallurgy of copper " proceeding of the symposium ,1981,annual meeting sem-aime, new york. 6. p.rutledge,1975, eng.min.j.,176(12),88. 7. calusaru, a. , 1979, "electrodeposition of metal powders" elesevier scientific pub., new york, p.250-276. 8. b.leach and henry,french pat. , 1920, 511,428. 9. d.w.drumiller ,r.w.moulton ,1950 , "electrodeposition of copper powder from acid sulpate bathes" industrial and engineering chemistry ,vol42,pages 2009-2102. 10. mantell, c.l., 1959, "electrodeposition of powders for powder metallurgy" j. electrochem. soc. vol. 106, no1, p.70-74. 11. i.d.enchevl,k.o.kharizanov, 1974, "preparation of copper powder by the method of electrolytic extraction", powder metallurgy and metal ceramic, consultants bureau, new york, vol.13, no.13, p.764-766. 12. rippere,e.ralph,1976, "electrolytic methods for production of high density copper powder ".u.s.pat. 3994785. 13. t. yamada, k. hirata, "method for producing copper powder"u.s.pat.2006/0213328a1 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 38 table 1:typical properties of copper powder produced by various methods properties atomized electrolytic hydrometallurgy solid state reduction copper, % 99-99.5 99-99.5 99-99.5 98-99 weight loss in h2, % 0.1-0.75 0.1-0.75 0.1-0.75 0.1-0.75 acid insoluble, % 0.5-0.1 max 0.03 max 0.03 max 0.3 max apparent density, g/cm3 2-4 1.5-4 1.5-2.5 2-4 flow, sec/50 gm 20-35 30-40 none 20-35 green strength, psi nil-2500 400-6000 nil-10,000 nil-2500 mpa nil-17.2 2.8-41.3 nil-68.9 nil-17.2 -325 mesh, % 25-80 5-90 60-95 25-50 table (2): the preferred conditions of the present work conditions the present work (powdery deposits) cathode: material current density( a/cm2) anode: material current density( a/cm2) copper ion concentration (gm/l) sulfuric acid concentration(gm/l) temperature( oc) cell voltage(volt) current efficiency (%) weight percent of particle size less than (63µm) (%) average particle size(µm ) yield (gm/cm2.hr.) specific surface area(cm2/gm) apparent density(gm/cm3) lead-6%antimony 0.16 copper (99.9%) 0.16 5 100 25-30 2.5 75 79.7 42 0.09 421 × 103 2.24 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 39 table (3): the purity of the prepared copper powder analysis chemical cu as fe bi ni cd si sn al measured values 99.7% <2ppm <2ppm <2ppm <10ppm <1ppm <1ppm <10ppm <1ppm 0.05 0.10 0.15 0.20 0.25 0.30 current density(a/cm^2) fi (2) ff t f t d it i ht t f d l th 63 40.00 50.00 60.00 70.00 80.00 90.00 w ei gh t p er ce nt o f c op pe r po w de r le ss th an 6 3u m (% ) copper ion concentration=5gm/l sulfuric acid concentration=25gm/l time of electrolysis=2hr. figure (1): the electrolytic cell cell body cathode (lead-6%antimony) anode (copper 99.9%) v a ps voltmeter ammeter power supply the electrolyte figure (2): effect of current density on the weight percent of copper powder less than 63µm al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 40 0.05 0.10 0.15 0.20 0.25 0.30 current density(a/cm^2) 40.00 50.00 60.00 70.00 80.00 90.00 c ur re nt e ff ic ie nc y( % ) copper ion concentration=5gm/l sulfuric acid concentration=25gm/l time of electrolysis=2hr. 0.05 0.10 0.15 0.20 0.25 0.30 current density(a/cm^2) figure (4) effect of current density on the yield 0.02 0.04 0.06 0.08 0.10 0.12 y ie ld (g m /c m ^2 .h r) copper ion concentration=5gm/l sulfuric acid concentration=25gm/l time of electrolysis=2hr. figure (3): effect of current density on the current efficiency figure (4): effect of current density on the yield al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 41 0.00 10.00 20.00 30.00 copper ion concentration(gm/l) f (5) ff t f i t ti th i ht t f d 20.00 30.00 40.00 50.00 60.00 w ei gh t p er ce nt o f c op pe r po w de r le ss th an 6 3u m current density=0.096a/cm^2 sulfuric acid concentration=25gm/l time of electrolysis=2hr. 0.00 10.00 20.00 30.00 copper ion concentration(gm/l) fuger(6) effect of copper ion concentration on current efficiency 60.00 70.00 80.00 90.00 100.00 c ur re nt e ff ic ie nc y( % ) current density=0.096a/cm^2 sulfuric acid concentration=25gm/l time of electrolysis=2hr. figure (5): effect of copper ion concentration on the weight percent of copper powder less than 63µm figure (6): effect of copper ion concentration on the current efficiency al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 42 0.00 10.00 20.00 30.00 copper ion concentration(gm/l) 0.03 0.04 0.05 y ie ld (g m /c m̂ 2. hr ) current density=0.096a/cm^2 sulfuric acid concentration=25gm/l time of electrolysis=2hr. 0.00 40.00 80.00 120.00 160.00 sulfuric acid concentration (gm/l) w ei gh t p er ce nt o f c op pe r po w de r le ss th an 6 3u m (% ) current density=0.16a/cm^2copper ion concentration=5gm/l time of electrolysis=2hr. figure (7): effect of copper ion concentration on the yield figure (8): effect of sulfuric acid concentration on the weight percent of copper powder less than al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 43 0.00 40.00 80.00 120.00 160.00 sulfuric acid concentration(gm/l) 60.00 64.00 68.00 72.00 76.00 80.00 c ur re nt e ff ic ie nc y( % ) current density=0.16a/cm^2 copper ion concentration=5gm/l time of electrolysis=2hr. 0.00 40.00 80.00 120.00 160.00 sulfuric acid concentration(gm/l) f (10) ff t f lf i id t ti th i ld 0.06 0.08 0.10 y ie ld (g m /c m̂ 2. hr ) current density=0.16a/cm^2 copper ion concentration=5gm/l time of electrolysis=2hr. figure (9): effect of sulfuric acid concentration on the current efficiency figure (10): effect of sulfuric acid concentration on the yield al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 44 0.00 2.00 4.00 6.00 time of electrolysis(hr.) figure(11)effect of electrolysis time on the weight percent of 20.00 40.00 60.00 80.00 100.00 w ei gh t p er ce nt o f c op pe r po w de r le ss th an 6 3u m (% ) current density=0.16a/cm^2copper ion concentration=5gm/l sulfuric acid concentration=100gm/l 0.00 2.00 4.00 6.00 time of electrolysis(hr.) fi (12) ff t f l t l i ti th t ffi i 50.00 60.00 70.00 80.00 90.00 c ur re nt e ff ic ie nc y( % ) current density=0.16a/cm^2 copper ion concentration=5gm/l sulfuric acid concentration=100gm/l figure (11): effect of electrolysis time on the weight percent of copper powder less than 63µm figure (12): effect of electrolysis time on the current efficiency al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 45 0.00 2.00 4.00 6.00 time of elecrolysis(hr.) fi (13) ff t f l t l i ti i ld 0.02 0.04 0.06 0.08 0.10 0.12 y ie ld (g m /c m ^2 .h r) figure (13): effect of electrolysis time on the yield \(microsoft word \\343\\344\\326\\317\\345 \\343\\355\\323\\321\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 41 باستخدام ألياف الكربون لسلوكية عينات األلمنيوم المقواة خارجياً دراسة تجريبية تحت تأثير عزوم أللي م صباح مهدي صالح.م م سليمان عناد مناور .م د ميسر محمد جمعة. م قسم الهندسة الميكانيكية قسم الهندسة الميكانيكية قسم الهندسة المدنية جامعة تكريت/كلية الهندسة جامعة تكريت /كلية الهندسةجامعة تكريت /كلية الهندسة وجزــــــمال باستخدام ، تقوية عينات األلمنيوم خارجيًا على الخواص الميكانيكية إن الهدف من هذا البحث هو دراسة تأثير ثابتة لجميع أنواع التقوية مع راتنج االيبوكسي )0.8%(وبنسبة كسر حجمي )٩٠-٠(لكربون النظامية ألياف ا ودراسة التغيرات الحاصلة على مقاومة عزم اللي وٕاجهاد القص لأللمنيوم ، كمادة رابطة sikadur-300نوع ري و تم استخدام ثالثة أنواع من األلمنيوم ذات المقطع العرضي الدائ من حيث تضمنت الدراسة عينات، ،النقي التقوية وهي التقوية الدائرية، والتقوية الحلزونية والتقوية الطولية ومن ثم فحص النماذج المصنعة مختبريًا على حيث أظهرت النتائج . ( smi mkii torsion testing machine )جهاز فحص االلتواء نوع نات المقواة دائريًا وبنسبة اقل من تلك العينات المقواة حلزونيًا تحسن واضح في مقاومة عزم اللي بالنسبة للعي .زيادة في مقاومة االلتواء أو زاويته أي فلم تظهر النتائج" أما بالنسبة للعينات المقواة طوليا ، ومخصائص األلمني، زاوية الدوران، قابلية تحمل عزم أللي، ألياف الكربون المسلحة بالبوليمرات: الكلمات الدالة .نسبة الكسر ألحجمي، ميكانيكية المواد الصلبة، خصائص ألمواد ألمعدنية experimental behavior of aluminun specimens (under torsion) strengthened externally by cfrp materials abstract the aim of this research is studying the effect of the fibers orientation on the reinforced aluminum specimens. the fibers are made of uniform carboin (0-90) of a volumetric fraction equal to 0.8%. this is for all the reinforcement fiber orientations, using sikadur -300 resin as connection stuff. three fiber orientations reinforcements have been used. these orientations are: circular, longitudinal and helical. then twisting test has been carried out for all the specimens. the test proved that the circular reinforcement improves twisting property, and the helical orientation gives less improvement, while the longitudinal one gives no improvement in the twisting property. keywords: cfrp, aluminum properties, torque-carrying capacity, minerals properties, mechanics of solids, angle of twist, volume fraction. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 42 المقدمة قــــد وصــــلت مراحــــل متقدمــــة وذلــــك لالســــتخدامات الواســــعة لمعــــدن األلمنيــــوم فــــي ه إن تقويــــة األلمنيــــوم وســــبائك مــن حيــث طريقــة االســتخالص وقابليــة التحمــل (التطبيقــات الحديثــة كونــه مــن المعــادن ذات المواصــفات الخاصــة ر البحـوث والدراسـات التـي تهـتم بـالتحري عـن وان أكثـ، ) للظروف البيئيـة والمرونـة العاليـة فـي االسـتخدام وغيرهـا الخواص الميكانيكية لهذا المعدن، في هذا المجال تتحدث عن تقوية األلمنيوم داخليًا وذلك بإضافة أنـواع خاصـة sic([1]-الفـا(من األلياف أو بإضافة مساحيق وحبيبات لمعادن أخرى مـع األلمنيـوم مثـل كاربيـد السـيلكون نـوع كما إن هذا النوع من التقوية يحتاج ، بعض الخواص الميكانيكية تحسينمن شانها والتي [2]جو حبيبات الزجاأ إلى تقنيـات حديثـة وباهظـة الـثمن بسـبب الظـروف الصـعبة التـي ترافـق عمليـات الصـب والسـباكة ومـا يرافقهـا مـن تـي تطرقـت إلـى التقويـة أمـا الدراسـات والبحـوث ال.مشاكل ومعوقات مثل تشكل الفجوات داخل هياكل المصـبوبات الخارجيـــة لأللمنيـــوم أو الهياكـــل الخارجيـــة فهـــي قليلـــة نســـبيا إذا مـــا قورنـــت بالدراســـات التطبيقيـــة فـــي تخصصـــات مثـل الـدعامات الكونكريتيـة واألعمـدة " الهندسة اإلنشائية والتي تناولت تقويـة العناصـر اإلنشـائية المختلفـة خارجيـا . الزجاج المسلحة بالبوليمرات مع راتنج االيبوكسي كمادة رابطة باستخدام ألياف الكربون أو ألياف ومــــن أهــــم الدراســــات وأحــــدثها فــــي مجــــال تقويــــة الحديــــد خارجيــــًا مــــع أليــــاف الكربــــون هــــو مــــا قــــام بــــه الباحثــــان )i.taerwe and i.vasseur( حيـث اسـتخدما عمـود مـن الفـوالذ وتقويتـه بأليـاف الكربـون [3] ٢٠٠٩عـام ثبتــــا تحســـنًا كبيـــرًا فــــي الخـــواص الميكانيكيـــة واإلنشــــائية للعمـــود مـــن ناحيــــة تحمـــل عـــزم االنحنــــاء طوليـــًا حيـــث ا ذلك ألن االتجاه الطولي لشـرائح أليـاف الكربـون تمثـل االتجـاه الرئيسـي لتـأثير ، واالجهادات المتولدة عن االنحناء الـــذي قـــد ) (bucklingاومـــة االنبعـــاج تســـليح العمـــود لمقاومـــة عـــزوم االنثنـــاء الناتجـــة مـــن األحمـــال وبالتـــالي مق . (euler theory )يحصل بسبب القوى المحورية المتولدة من األحمال المركزية حسب نظرية أويلر بدراســة ســلوكية األعمــدة [4] 2006عــام (m. kaminski and t. trapko)وكــذلك قــام الباحثــان ، ت باســتخدام أليــاف الكربــون المســلحة بــالبوليمرات الخرســانية المســلحة ولنمــاذج متعــددة بعــد تقويتهــا بعــدة حــاال ودراســة العالقــة بــين نســبة التســليح الخــارجي وقابليــة تحمــل ،وأعطــت النتــائج تحســن واضــح فــي مقاومــة االنثنــاء .الحادث وعالقته بنوع التسليح واالنفعالالعنصر لألحمال advantages of cfrpالفوائد ا�ساسية من استخدام ألياف الكربون يمكن تلخيص أهم فوائد استخدام هذه المادة شائعة االستخدام فـي معظـم التطبيقـات الهندسـية وخاصـة فـي مجـال التقويــات اإلنشــائية لروافــد الجســور والعناصــر اإلنشــائية المختلفــة وغيرهــا إضــافة التســاع تطبيقاتهــا فــي مجــاالت :[7]هندسة الميكانيك والمعادن بالنقاط التالية .ومة في أنظمة التقوية من خالل مقاومة التآكل والتأثيرات القاعديةالديم. ١ .توفرها بكافة األطوال وٕامكانية نقلها بصورة روالت حسب أسلوب اإلنتاج. ٢ وامتالكها لمعامل مرونـة عـالي يصـل ألكثـر mpa 2400مقاومتها العالية الجهادات الشد لتصل ألكثر من . ٣ .mpa 165000من al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 43 light weight material) .(ة الوزن مادة خفيف. ٤ .التحتاج ألسلوب معقد في التثبيت وتعمل على تحسين خصائص مقاومة المنشآت للحرائق.٥ .التحتاج لكلف صيانة عالية.٦ علــى مقاومــة االنثنــاء والقــص مــن خــالل " أن ألســتخدام أليــاف الكربــون فــي المنشــآت الخرســانية تــأثير كبيــر جــدا حيث تستخدم في .ductility enhancement of concrete structures نة المطيلية زيادة خصائص الخرسا جديــدة التقنيــة اختيــرت هــذه المــادة فــي ال ،ف واألعمــدة وٕاعــادة تأهيــل المنشــآتتقويــات العتبــات والجســور والســقو بـة المسـتخدمة لهـذا للتقوية بسـبب مقاومـة شـدها الخارجيـة العاليـة وصـالدتها مقارنـة مـع مثيالتهـا مـن المـواد المرك يبـــين المقارنـــة بـــين خصـــائص االنفعـــال واإلجهـــاد ألليـــاف الكربـــون وحديـــد التســـليح ٦الشـــكل رقـــم و، الغـــرض .[8]االعتيادي ألجانب ألعملي ألجهاز ألمستخدم ( smi mkii torsion testing machine)تم استخدام جهــــاز فحص االلتواء ذو الرمز حيث ان هذا الجهاز يستخدم لقياس عزم االلتواء لقيم تصل الى،لمصنعة مختبرياً لفحص واختبار العينات ا n.m6بين وألقطار عينات تتراوح ٤٠ mm 22الىmm 700 وبطول عينة كحد اقصى هو mm وكما . ١الشكل رقم وضح في ألمواد ألمستخدمة وبتحليل كيمياوي ملم ٢١٠ ملم وبطول ٢٢ المقطع بقطر دائريالنقي تم استخدام قضيب صلد من األلمنيوم -أ وأجريـت عليـه عمليـات التشـغيل الميكـانيكي لتحضـير عينـات بأبعـاد قياسـية وحسـب ١الجدول رقم كما مبين فـي والـذي يحـدد طـول العينـة المطلـوب ١الشكل رقـم كما مبين فـي ، المستخدم في عملية الفحص مواصفات الجهاز .٢الشكل رقم كما في ، زفحصها وأسلوب تركيبها في الجها كمــادة رابطــة بــين أليــاف الكربــون والعينــات المصــنعة مــن sikadur300تــم اســتخدام مــادة االيبوكســي نــوع -ب الخــواص العامــة لمــادة االيبوكســي المســتخدمة كمــادة رابطــة بــين أليــاف ، ٢ الجــدول رقــم، ويبــين [5]األلمنيــوم .)األلمنيوم(الكربون والمعدن المستخدم الجـدول رقـم والمبينـة مواصـفاتها فـي sika-wrap-300cنـوع ) ٩٠-٠(ربون النظامية ـــــــــستخدام ألياف الكأ -ج والمنتجــة مــن قبــل شــركة ســيكا التركيــة حيــث تــم الحصــول علــى مواصــفات المــادة مــن مرجــع المواصــفات [6] ٣ .الخاص لهذه الشركة al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 44 تحضير ألعينات بالمواصــفاتعينــات حضــيرالميكــانيكي علــى عينــات معــدن األلمنيــوم المســتخدم لتبعــد إجــراء عمليــة التشــغيل فقد تم مزج مادة االيبوكسي ، "وكما موضح في األشكال المذكورة الحقا n8المشار اليها وبدرجة خشونة وأالبعاد ملـم ) 4mm(ملـم وعـرض ) mm٩٠(بطـول مع المصلد الخاص بهـا وتقطيـع أليـاف الكربـون حسـب نـوع التقويـة حيث تمت تقوية العينات بثالث طرق مختلفة لدراسة التحليل االمثل في االستخدام وتقليل زاوية االلتواء الـى اقـل ومـن خـالل تطبيـق المعادلـة التاليـة لصـيغة عـزم الـدوران ،الـى حـد الفشـل" وزيادة قابلية التحمل وصـوال حد ممكن : وكما يليوران العينة تحت تاثير عزم االلتواء باالمكان احتساب المعامالت المؤثرة وأهمها زاوية د gjtl /=θ :حيث أن θ زاوية نصف قطرية(زاوية الدوران( angle of twist –(rad) . t – م. نت(االلتواء عزم ((n.m), torque. l – ملم(طول العينة (specimen length – (mm). g٢ملم/ نت ،)الجساءة(المقطع الدة معامل ص( (mpa), modulus of rigidity. j – ٤ملم ،)للمقطع الدائري(القطري عزم القصور الذاتي (mm4) – torsional constant. لدوران على السلوكية النظرية لعزوم أللي أو ا" نواع التقوية اعتماداالتالية ألثالثة تضمنت الدراسة المقترحات أل :وعالقتها باجهادات القص وكما يلي تم تقطيـع أليـاف الكربـون علـى : (circular (or ties) cfrp strengthened model )التقوية الدائرية -أ ملـــم ) ٠.١٦٦(وبســـمك ) باتجـــاه عـــزم اللـــي(شـــكل حلقـــات دائريـــة ولصـــقها علـــى العينـــات باتجـــاه عقـــارب الســـاعة ملـم وكمـا مبـين ) ٢١(لتكـون المسـافة بـين كـل حلقـة والتـي تليهـا ، ربـع حلقـاتملم لكل حلقة وبواقع أ) ٤(وعرض .٣الشكل رقم في تم قطع شريحة من ألياف : ( spiral (or helical) cfrp strengthened model)التقوية الحلزونية -ب فس اتجـاه عـزم اللـي ولصـقها علـى العينـة بـن، فـي الـنمط األول للتقويـة مالكربون بنفس السمك و العرض المسـتخد spiral الثـاني مـن أنمـاط التقويـة المقترحـة نـوعلتكـوين ال، 4الشـكل رقـم درجـة وكمـا هـو مبـين فـي ٤٥وبزاويـة strengthened by cfrp . حيث تـم تقطيـع ثـالث :(longitudinal strengthened model by cfrp strips)التقوية الطولية -ج للحفــاظ علــى ثبــات نســبة الكســر ) ملــم ٣(ملــم أيضــا وبعــرض اقــل (0.166)شــرائح مــن أليــاف الكربــون بســمك وتـم لصـقها بالمـادة الرابطـة علـى ، للكربـون فـايبر ولكافـة أنـواع التقويـة ( volume fraction , vf)ألحجمـي .٥الشكل العينات باتجاه المحور الطولي للعينة وكما هو مبين في al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 45 النتائج والمناقشة نتائج قابلة للدراسة والتحليل والمقارنة فقد تم تحضير ثالث عينات من كل نوع من أنواع ولغرض الحصول على ســاعة لضــمان اكتســاب المــادة ألالصــقة الحــد ٢٤وتركــت تلــك العينــات لمــدة ، التقويــة المقترحــة لعينــات األلمنيــوم . لفحصأ األقصى من قوة االلتصاق قبل :بين مايليبعد فحص العينات على جهاز فحص االلتواء ت حيــث تظهــر قــيم عــزوم اللــي ( أظهــرت النتــائج إن العينــات ذات التقويــة الدائريــة تمتلــك مقاومــة لــي عاليــة -١ مع العينات األخـرى تهامقارنعند ) ١الشكل رقم لكل فحص على الشاشة الرقمية لجهاز الفحص والموضحة في دورة )٢٠٠(ت وصـــلت حـــد الفشـــل بعـــدد دورات أن هـــذه العينـــا وجـــد) ذات التقويـــة الحلزونيـــة والتقويـــة الطوليـــة( ٣٣.٨(مــع عــزم التــواء أقصــى بقيمــة ) درجــات ٦ تعــادل الــدورة الواحــدة فــي جهــاز الفحــص المســتخدم أن حيــثو ( :عزم ألليباستخدام معادلة تم اجراء هذه الحساباتو )متر.نيوتن θ×= l gj t دورة )٩٠(لحلزونيــة وصــلت حـــد الفشــل بعــدد دورات يصــل إلـــى فــي حــين أن العينــات المقــواة بأليـــاف الكربــون ا ، وأظهـــرت العينـــات ذات التقويـــة الطوليـــة تقـــارب النتـــائج مـــع عينـــات ) متـــر.نيـــوتن ٣٣.٢(وبعـــزم التـــواء أقصـــى دورة وبعـــزم ) ٦٥(بعـــدد دورات ) ذات التقويـــة الطوليـــة(األلمنيـــوم الخاليـــة مـــن التقويـــة حيـــث وصـــلت حـــد الفشـــل ) ٨٠(بعــدد دورات قــدره ، بينمــا كانــت نتــائج العينــات التــي بــدون تقويــة هــي ، ) متــر.نيــوتن ٣٠.٤(أقصــى قيمتــه 8الشـكل رقـم وكمـا مبـين فـي ، ) متـر. نيـوتن ٣١.٦(وبعزم لـي يصـل لقيمـة عظمـى مقـدارها ، دورة لحد الفشل .٩ والشكل رقم تـأثير التقويـة إلـىالمفحوصـة يشـير بدقـة ومأاللمني لعيناتلذي يظهر في مقاومة عزم الدوران أن الفرق الواضح ا المستخدمة ونمط تركيب شرائح أأللياف ومدى استجابة العينة لتأثيرات اجهادات القص وأحمال أاللتـواء المسـلطة زيــادة مــايعرف بزاويــة أووبالتــالي زيــادة قابليــة تحمــل العينــة مــن خــالل زيــادة عــدد الــدورات حســب قــراءة الجهــاز ). angle of twist (الدوران ، أن لنــوع الفشــل الحاصــل علــى مســتوى العينــة الواحــدة فــي كــل مجموعــة مــن مجــاميع العينــات الــثالث -٢ شكل محدد يعتمد على قابلية تحمل العينة وتأثير وجود التقوية الخارجيـة باألليـاف بأنواعهـا الـثالث وعالقتهـا مـع حيـث يحصـل plastic torsional failureني اللدنوهو مايدعى بالفشل ألدورا، ) غير المقواة(عينة المقارنة وكمـا مبـين ، بشكل تـدريجي يعتمـد علـى مواصـفات المـادة وتركيبهـا الفيزيـائي والهندسـي وخصائصـها الميكانيكيـة .7الشكل رقم في هــي أفضــل أنــواع circular strengthened بعــد مقارنــة النتــائج أعــاله تبــين بــان التقويــة الدائريــة -٣ بالمقارنـة مـع ) متر.نيوتن ٣٣.٨(مع عزوم لي أقوى نسبيًا ) دورة ٢٠٠(ناحية تحمل عدد دورات اكبر التقوية من ) متــر.نيـوتن ٠.٦(وبحــدود ) دورة ١١٠( إلـىالفـرق فــي عـدد الـدورات يصــل إنحيـث نالحــظ ، بقيـة أنـواع التقويــة عـن نمـاذج التقويـة ) متـر.نيـوتن ٣.٤(و) دورة ١٣٥(وبحـدود، " في عزم أللي عن نمـاذج العينـات المقـواة حلزونيـا al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 46 أن الســـبب فـــي ذلـــك يعـــود الـــى ان العينـــات المقـــواة دائريـــا باليـــاف الكربـــون كانـــت لهـــا ســـلوكية لمقاومـــة . الطوليـــة بينما كانت سلوكية العينات المقـواة حلزونيـا هـي اقـل والسـبب فـي ذلـك هـو وجـود مركبـات ، اجهادات القص فقط . القص دإجهامع ) انحناء ولي(أخرى إجهاد إن التقوية الطولية لم تساعد على زيادة مقاومة اللي في العينات المصنعة بل علـى العكـس سـاهمت فـي -٤ األمـر الـذي انعكـس علـى ، لعينـات مقارنـة مـع عينـات المقارنـة المفحوصـة ا )gالجسـاءة (معامل الصـالدة تقليل وكمـا مبـين فـي .ى عزم أللي الناتج ـــــــلك علعدد الدورات التي من ألممكن تحملها لحين الوصول لحد الفشل وكذ .10الشكل رقم تشـير بوضـوح الـى تفاصـيل الحمـل المسـلط وتغـاير ، من خالل مالحظـة المنحنيـات فـي األشـكال المرفقـة -٥ .عدد الدورات بشكل تدريجي وحدود الفشل الناتج صادرــــــلمأ [1]mohammed s. waheed and sadeer m. majeed , “ the mechanical properties of al matrix composites ”, journals of engineer and technology , vol.15, no.27,2009. [2]thikraa m. ali , “ study the mechanical properties of al-glass composite “ , journals of engineer and technology, vol.14, no.27 , 2009. [3]l. taerwe , l. vasseur and s. matthys ,” external strengthening of continuous beams with sfrp” , 2009. [4]m. kaminski and t. trapko , “ experimental behavior of reinforced concrete column models strengthened by cfrp materials” , journal of civil engineering and management”, vol. xii , no. 2 ,2006, p.109-115. [5]sikadur-330, " 2-part epoxy impregnation resin" , edition 2006. [6]sika-wrap-300c , " woven carbon fiber fabric for structural strengthening" , edition 2006. [7]william d. and callister jr." materials science and engineering an introduction" , john wiley & sons inc., 2007. [8]schanerch d., standford, k. and lanier, b., "use of high modulus carbon fibre reinforced polymer (cfrp) for strengthening steel structures", department of civil construction and environmental engineering, north carolina state university, u.s.a., 2001. يبين التحليل الكيمياوي لعينات األلمنيوم المستخدمة في البحث )١(جدول رقم al sn pb ni cr zn mg mn fe si 99.66 0.004 0.006 0.002 0.004 0.009 0.006 0.007 0.193 0.09 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 47 sikadur-300 [5] يبين المواصفات الميكانيكية لاليبوكسي نوع ٢جدول رقم q units property ١.٣ kg/l3 density ٣٠ mpa tensile strength ٣٨٠٠ gpa e-modulus sika warp-300c [6] يبين المواصفات الميكانيكية اللياف الكربون نوع ٣جدول q units property ١.٣ g/cm3 fiber density ٣٩٠٠ mpa tensile strength يبين جهاز تسليط عزم أاللتواء وقياس زاوية الدوران ١شكل رقم يبين أحد طرفي تثبيت العينة في جهاز تسليط عزم أاللتواء ٢شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 48 "ون حلقياعينة أأللمنيوم المقواة بشريحة ألياف الكرب ٣شكل رقم "عينة أأللمنيوم المقواة بشريحة ألياف الكربون حلزونيا ٤شكل رقم "عينة أأللمنيوم المقواة بشرائح ألياف الكربون طوليا ٥شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 49 [8] أللياف الكربون وحديد التسليح االعتيادي) أالنفعالأإلجهاد(يمثل المقارنة في عالقة 6شكل رقم الفشل لعينات أأللمنيوم المقواة بشرائح ألياف الكربون مع عينة المقارنةيوضح ٧شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 50 fig.(8):torque-no.of revolution relation for regular sample with compare between reference and spiral and ties cfrp 0 5 10 15 20 25 30 35 40 0 0.5 1 1.5 2 2.5 3 3.5 4 no. of revolution (2pi) t o rq u e (k n .m ) with ties cfrp reference s ample with s piral cfrp with long. cfrp fig.(9):torque-no. of revolution relation between reference and ties cfrp 0 5 10 15 20 25 30 35 40 45 50 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 no. of revolution (2pi) t o rq u e (n .m ) reference sam ple ties cfrp al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 51 fig.(10): torque-angle of twist relation for longitudinal strips 0 5 10 15 20 25 30 35 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 no. of revolution(2pi) t o rq u e c ap a ci ty (k n .m ) refrence sample longitudinal cfrp template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 203 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the effect of porosity on the yield of carbon nanotubes ahmad flayyih hussein, university of technology, department of production engineering and metallurgy, baghdad, iraq. email: afh_uot@yahoo.com aqeel ali al-attar, university of technology, department of production engineering and metallurgy, baghdad, iraq. email: akeel_attar@yahoo.com received on 1 december 2016 accepted on 4 april 2017 abstract: in this work, the porous magnesium alloy (az91 ) was prepared by space holder technique to deposit carbon nanotubes, novalac powder was used as space holding and fugitive materials with different particle size (≥20 µm, ≥500 µm) and amount (50, 52, 54, 56, 58, 60%wt.). impact of novalac powder (particle size and additive percent) on density and porosity of porous az91 alloy was studied. fine novalac powder (≥20 µm) not recommended in the porous az91 alloy preparation, concurrently coarse novalac powder (≥500 µm) was suitable for that purpose. it was found that the density of az91 alloy decreased with increasing novalac concentration. carbon nanotubes were deposited on the porous az91 alloy by catalytic chemical vapor deposition whereas niso4.6h2o used as catalyst, acetylene gas as a carbon source and argon gas as a carrier gas with flow rate percent 1:1, at 575°c process temperature for 30 min. multiwall carbon nanotubes were obtained and characterized by x-ray diffraction and scanning electron microscopy techniques. the average diameter of the multi wall carbon nanotubes was (46 nm). although the porosity percent of az91 alloy was not majorly effect proportionally by the increasing of an additive novalac percent, the yield (quantity) of multiwall carbon nanotubes was enhancing due to increase the porous az91 alloy surface area.. keywords: porous materials, chemical vapor deposition and carbon nanotubes. 1. introduction multiwall carbon nanotubes (mwnts) was discovered by iijima [1]. carbon nanotubes (cnts) had interested more and more research concerns, because of their extraordinary properties and different potential applications [2, 3]. carbon nanotubes had matchless properties (mechanical, thermal, electrical and optical etc.) that made them potentially practical in a wide diversity of applications [4, 5]. carbon nanotubes were prepared with three main methods, arc discharge, laser ablation and chemical vapor deposition [6]. chemical vapor deposition cvd used like simplicity and up scalability, which preferred in commercial production [7]. many factors like carrier gas, carbon source, catalyst type, substrate, mailto:afh_uot@yahoo.com mailto:akeel_attar@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 204 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. process temperature and surface area influenced on the synthesis of cnts (length, diameter, type and yield etc.) in chemical vapor deposition cvd method [8]. there are many methods to manufacture porous metallic materials, and these different methods could be arranged based on the state of the metal as an example: to form powdered solid metal from liquid metal, through a metal vapor or gaseous metallic substances and also from a metal ion solution, the solid metal in the powdered form process could be acquired porous materials by using filler materials (space-holding) and metal powders. the mass of space-holding material is mixed with tiny metal powder as shown in figure 1. suitable solvent [9] or even an organic binder [10] perhaps used for mixing the space holders and the metal powders [11]. figure 1: for preparation of porous materials by space holder technique. ceramic particles or cavity spheres, polymer grains or cavity polymer spheres, salts, or even metals could be used as space holders. then, the filled mass either simply compacted at room temperature[12], or pressed at elevated temperatures to improve compaction so, it became sintering processes among the metal powder particles if the space holders were heat resistant [13]. in both states, a compound became acquired, and consisted of a metal matrix with inserted small grains filler. if the metal content was low enough, it would remove the space holder material almost entirely in an additional process step because the network formed by the filled material was interconnected. this could be performed by thermal treatment, leaching, or by using of an aqueous solvent. a final sintering step could be implemented to more density of porous metallic network [14, 15]. the aim of this study was to prepare porous alloy with high porosity percent, also to study the impact of a porosity percent in az91 alloy on yield (quantity) of carbon nanotubes, which prepared by chemical vapor deposition process in order to increase the production of carbon nanotubes. also, it aims to the al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 205 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. possibility of controlling the deposited carbon nanotubes quantities through dominating on the percentage of the porous az91 alloy. 2. experimental work this part is divided into two stages: preparation of porous material. preparation of carbon nanotubes (cnts). 2.1. preparation of porous material magnesium alloy (az91 mg-9 wt%al-0.7%zn) was prepared by powder metallurgy as porous material. the specification of materials used is shown in table 1. table 1: the particle size of materials used. the metal powders were mixed in a mortar for 5 minutes, followed by mixing in a ball mill for 30 minutes at rotation speed 750 rpm and this is az91 powder. the powder metals and novalac powder (used as holding material with different particle size (≥20 µm, ≥500 µm) were mixed in a mortar. the az91 alloy powders was mixed with different wt% (50, 52, 54, 56, 58, 60%wt.) of novalac powder. the powders were compacted by using a tool steel die of 15mm diameter with compacting pressure 174 mpa. four samples were prepared for each mix. several sintering attempts were tried. first the sample were heated under argon at 250˚c , holding at this temperature for 30 minutes ,and then the sample were furnace cooled to room temperature. it was found that in this sintering cycle, the temperature wasn't sufficient to remove all the novalac from the compacting, therefore another attempt was utilized. the proper sintering process was done under argon by heating the green samples to 250˚c and hold at this temperature for 30 minutes. the temperature was then raised to 500˚c and hold at this temperature for another 30 minutes. the samples were then furnace cooled to room temperature. the second attempt had given good samples, and then all of them were sintered by using that heating cycle. the samples were cleaned in acetone followed by ultrasonic cleaning for 10 minutes, and then oven dried at 100˚c for 30 minutes. the porous az91 alloy became ready to make density and porosity tests. no. material particle size µm 1 mg powder ≥75 µm fluka co. germany 2 al powder ≥53 µm fluka co. germany 3 zn powder ≥75 µm fluka co. germany 4 mn powder ≥75 µm fluka co. germany 5 novalak powder ≥20 µm trade india 6 novalak powder ≥500 µm trade india al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 206 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.2. preparation of carbon nanotube 2.2.1. catalyst preparation the catalyst solution was prepared by dissolving 1 gm of niso4.6h2o in 100ml of distilled water. the solution was then mixed ultrasonically for 20 minutes. the az91 sintered sampled were dipped in niso4.6h2o catalyst solution for 30 min. each sample was then dried in an oven at 150˚c for 30 minutes in atmospheric air. the weight of each sample was taken using 4 digits’ electrical balance. these az91 sintered and dipping coated samples are ready to be used in chemical vapor deposition (cvd) process. 2.2.2. furnace description two furnaces were used as primary and secondary heating furnace. each furnace with quartz tube length (600mm) and (47mm) inside diameter with maximum temperature (1100oc). another long inner quartz tube (reaction chamber) was inserted inside the two furnaces. this quartz tube reaction chamber is 600mm long with inside diameter 28mm and 30 mm outside diameter. the first half of the reaction chamber is called secondary chamber used to preheat the reaction gases. the second half of the reaction chamber is called primary chamber and contain az91 sintered coated samples. these az91 were put at distance 15 cm from the outlet end. the acetylene and argon gases are fed through the secondary chamber which was used for preheating of acetylene and argon gases. these gases were discharge from primary chamber as shown in figure 2. figure 2: illustration of the cvd furnace system. the heat distribution of the primary reaction chamber is shown in figure 3. the reaction chamber was charged with argon gas first to avoid any oxidation until the temperature of the secondary furnace and the primary furnace reach 300 and 575 °c respectively. then, acetylene (as carbon source) and argon gases were charged together into the reaction chamber. the flow rates of the two gases (1:1 slpm) for 30 minutes. then the sample was allowed to cool under argon into room temperature. the weight of each sample was recorded (4 samples for each run) before and after cvd process to find the weight of cnts deposited. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 207 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3): temperature distribution in side tube furnace. 2.2.3. cnts purification the produced cnts were purified by heating 0.5 g of mwcnts inside furnace at 450˚c for 2hrs under atmospheric air to oxidize the amorphous carbon. then the cnts were soaked in 250 ml of acidic solution consisted of sulfuric acid and nitric acid with a ratio (3:1) respectively [15] and stirred for 1 hour at 90˚c using magnetic stirrer hot plate. the cnts solution was then centrifuged using a centrifuge (unimedica 800 centrifuge, china) at 3000 rpm for 10 minutes. the remaining cnts would be washed with deionized water and then centrifuged for another 10 minutes at 3000 rpm. this process was repeated 3-4 times until the ph of the solution is 7. cnts were then dried in an oven at 90˚c for 2 hours [16]. the purified cnts were characterized by xrd. 3. tests in this part there were some tests which done on pours az91 alloy samples and the other would be performed on carbon nanotubes. 3.1. density and porosity test astm d 792 standard reference was used in density and porosity measurements, which were based on archimedes principle. the density of the material and the porosity were calculated using equation 1 and 2 respectively. four measurement were done and the average value was taken [16]. (1) where sp.gr = specific gravity of material, wd= weight of material in air (gm), wi= weight of material suspended in acetone (gm) [4]. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 208 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (2) where p= porosity of material ws = weight of wet material, i.e. weight of soaked material in air. 3.2. scanning electron microscopy carbon nanotubes samples were characterized using hitachi s-4160 scanning electron microscope (sem), scanning electron microscope lab. /tehran university. 3.3. x-ray diffraction (xrd) test the x-ray diffraction test was done for carbon nanotubes samples at specialist institute for mechanical industry, baghdad, republic of iraq. 4. results and discussion 4.1. density and porosity test in this work, pours az91 alloy sample was prepared by using novalac as space holding material with particle size (20< particle size< 500 µm) and (≥500 µm). in this work, it was found that all the samples were failed when novalac powder particle size (20< particle size< 500 µm) as shown in figure 4. this is due to the small particle size of novalac powder particle size. this very fine powder is situated interstitially into particles of metal powders. during sintering process, when novalac evaporated, the gases entrapped between metal particles causing cracks of the samples as shown in figure 4. figure (4): show failed samples. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 209 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. when the novalac powder with a particle size (≥500 µm) was used, no cracks in the sintered samples were observed and these sample are good as shown in figure 5.in sintering process, when coarse novalac powder evaporated there was enough space for the gases to escape and no entrapment as shown in figure 5. therefore, the powder particles size of the metal powder should be smaller than the average powder particles size of the space holder [17]. figure (5): show open pores and close pores in good samples. from figure 6, the density of the sintered az91 decreases with novalac percent due the open pores and the impurities left after novalac evaporation, where a general difficulty of this method is the removal of large quantities of the space holder materials from the compacted mix, this result agrees with previous study [18]. figure (6): effect the novalac additive percent on the az91 alloy density. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 210 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the porosity of the az91 sintered samples vs. novalac wt% is shown in figure 7. the change in the porosity does not proportional to the changes in the density. this is may be due to the closed pores which contained impurities caused by novalac evaporation and the segregation of novalac particle during mixing the metal powder with the often much larger space holders material, where segregation minimize novalac activity in increasing az91 sintered porosity, this result agrees with previous study [19]. figure (7): effect novalac additive percent on the az91 alloy porosity. 4.2. scanning electron microscope (sem) and xrd the cnts were examined by sem and the average diameter was (46.66 nm), as shown in figure 8. this indicates that the produced cnts by cvd method are mwcnts. xrd of multiwall carbon nanotubes (mwcnts) shows the peak at 26.6 based on the (0 0 2) diffracting plane as shown in figure 9. the (0 0 2) peak was shifted from 26.6 to 26 due to the high curvature and high strain energy of mwcnts [20]. figure (8): show the sem image for carbon nanotubes. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 211 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (9): xrd of mwcnts. the quantity of mwcnts yield produced by cvd using az91 as porous substrate as a function of novalac wt. % is shown in figure 10. the quantity of mwcnts (yield) is influenced by az91 open pores surfaces and the lumpy surface which left by segregated novalac contributing to increase az91 surface area, from figure 10 can be noted the fluctuating in the yield of cnts with a clear increase along increasing in novalac wt.%, to discuss that , from figure 7 it could note the porosity at 54 and 58 novalac wt.% are approximately equal but, in figure 10 the quantity of mwcnts yield at 58 novalac wt.% is a doubled of the quantity at 54 novalac wt.% ,this improve that the porosity is not the only influential on the quantity of mwcnts yield but there is another influential, which is the lumpy surface which left by segregated novalac on az91 surface, the last factor might be the main factor in increasing carbon nanotubes quantity. figure (10): effect the novalac additive percent on the cnts quantity. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 212 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. conclusions particle size of the space holder (novalac powder) should be appropriated to particle size of metal powders to stop samples cracks. the closed pores had negative affecting on the activated porosity (surface area). it is not recommend using novalac powder in the preparation of porous metallic materials due to the segregation which occurred to the novalac powder. although the increasing of which occurred in deposited carbon nanotube in compatible with the raising of porosity, where it is not controlled on it, due to the difficulty of controlling on porosity percentage of az91 alloy. the carbon nanotubes quantity would be increased with novalac powder percent increase. 6. acknowledgements the authors were grateful for stuff of production engineering and metallurgy department/university of technology-baghdad for their support and the stuff of scanning electron microscope lab. /tehran university. references 1. ajayan, p. m. and s. iijima, "capillarity-induced filling of carbon nanotubes", nature, v. 361, p.p. 333-334, 1993. 2. ansaree, m. j. and s. upadhyay, "electrical characterization of porous la-doped basno using impedance spectroscopy", ionics, v. 23, p.p. 213-217, 2015. 3. gerke, k. m., "studying structure and determining permeability of materials based on x-ray microtomography data (using porous ceramics as an example)." inorganic materials, v. 51, p.p. 951-957, 2015. 4. hou, z., "effects of pore shape and porosity on the dielectric constant of porous β-sialon ceramics." journal of the european ceramic society, v. 114, p.p. 452-458, 2015. 5. iijima, s., "the effected factors on the cnts properties", chem. sripta, v. l4, p.p. 117-123, 1978. 6. iijima, s., " helical microtubules of graphitic carbon", nature, v. 354, p.p. 56-58, 1991. 7. iijima, s., " growth model for carbon nanotubes" physical review letters, v. 69, p.p. 3100-3103, 1992. 8. iijima, s., " single-shell carbon nanotubes of 1-nm diameter", nature, v. 356, p.p. 776-778, 1992. 9. kim, d. h., "a microreactor with metallic catalyst support for hydrogen production by partial oxidation of dimethyl ether" chemical engineering journal, v. 280, p.p. 468-474, (2015). 10. kirichenko, o. v. "filtering properties of porous materials made of thin stainless steel fibers." powder metallurgy and metal ceramics, v. 317, p.p. 625-631, 2015. 11. li, w., "sintering of bi-porous titanium dioxide scaffolds: experimentation, modeling and simulation" materials science and engineering, v. a 636, p.p. 148-156, 2015. 12. liu, x., "characterization and application of porous ceramic prepared through reactive synthesis" materials and design, v. 79, p.p. 94-98, 2015. 13. mintmire, j. w., " fullerene tubules metallic", physical review letters, v. 68, p.p. 631-634, 1992. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 213 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 14. oberlin, a. and m. endo, " filamentous growth of carbon through benzene decomposition”, journal of crystal growth, v. 32, p.p. 335-349, 1976. 15. safronova, t., "erratum to: porous ceramic based on calcium pyrophosphate", refractories and industrial ceramics, v. 38, p.p. 117-123, 2015. 16. saito, r., " electronic structure of graphene tubules based on c60”, physical review b, v. 46, p.p. 18041811, 1992. 17. trifonov, y. g., "highly porous strong ceramic material made from powder prepared by chemical dispersion of aluminum alloy containing lithium" refractories and industrial ceramics, v. 457, p.p. 163-168, 2015. 18. vajtai, r., "controlled growth of carbon nanotubes." philosophical transactions: mathematical", physical and engineering sciences, v. 362, p.p. 2143-2160, 2004. 19. yin, l., "silicon nitride foams with uniform pore structure prepared by using protein foaming method with a planetary ball-milling foaming route", journal of porous materials, v. 62, p.p. 22-26, 2015. 20. zhang, r., "porous of ceramics with a centrosymmetric structure produced by freeze casting" ceramics international, v. 48, p.p. 216-222, 2015. al-qadisiya journal for engineering sciences, vol. 5, no. 4, 341-346, year 2012 341 physicaland thermal properties of fiber(s-type)reinforced compositearaldite resin (gy 260) mahmoud a. hassan al-qadisiya university assist lecturer abstract this study aims to investigate: first, study the effect of changing the reinforcement percentage by fibers on mechanical properties (impact, tensile, and compressive strength) for composite material consist of araldite resin reinforced by chopped glass fibers with density (2.6g/cm 3 ) .glass fibers was mixed with araldite resin in different weight reinforcement percentage (20%, 40%, 60%) . the best results was obtained with large reinforcement percentage (60%). second, study the effect ofthe same above reinforcement percentage on thermal conducting of composite material, where the result show increased thermal conducting with increasing percentage of reinforcement. fourier equation was used to calculate the changing in thermal conductivity coefficient (k) for composite material. keywords: composite material, thermal properties, mechanical properties . introduction a composite is commonly defined as a combination of two or more distinct materials, each of which retains its own distinctive properties, to create a new material with properties that cannot be achieved by any of the components acting alone. using this definition, it can be determined that a wide range of engineering materials fall into this category. for example, concrete is a composite because it is a mixture of portland cement and aggregate. fiberglass sheet is a composite since it is made of glass fibers imbedded in a polymer. composite materials are said to have two phases. the reinforcing phase is the fibers, sheets, or particles that are embedded in the matrix phase. the reinforcing material and the matrix material can be metal, ceramic, or polymer. typically, reinforcing materials are strong with low densities while the matrix is usually a ductile, or tough, material [rao and rodrigues, 2012]. the thermal conductivity of a material is equivalent to the quantity of heat that passes in unit time through unit area of a plate, when its opposite faces are subject to unit temperature gradient (e.g. one degree temperature difference across a thickness of one unit). for non-metallic solids like composites, the heat transfer is view as being transferred via lattice vibrations, as atoms vibrating more energetically at one part of a solid transfer that energy to less energetic neighboring atoms. this can be enhanced by cooperative motion in the form of propagating lattice waves, which in the quantum limit are quantized as phonons. practically, there is so much variability for non-metallic solids that we normally just characterize the substance with a measured thermal conductivity when doing ordinary calculations [incropera, 1996]. aralditeresin belong to epoxy group which have excellent thermal and physical properties, and usually used in composite materials for different application, where it distinct by excellent adhesive capability especially to fibers, also it retain constant dimension after dryness [ali et. al., 2011]. g.morom, e.drukkler, a. weinberg, and j. banbaji studied the effect of hybrid fibers (carbon /kevlar) on the impact strength of epoxy resin [morom, 1986] . also ali investigated the effect of changing the reinforcement percentage by fibers on mechanical properties, for composite material mahmoud a.hassan 342 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 341-346, year 2012          x t akq   x t consists of conbextra epoxy (ep-10) resin reinforced by biaxial woven roving kevlarfibers [ali,2009]. azhdar studied the impact fracture toughness of fiber reinforced epoxy resin [azhdar, 1992]. abbas , ali , and sajed studied effect the change of reinforcement percentage of fibers on the thermal conductivity for polymeric composite material consist of conbextra epoxy (ep-10)resin reinforced by biaxial woven roving s–type glass fibers [abbas and ali, 2009]. kahtan and ali studied the behavior for composite material consisted from unsaturated polyester resin reinforced by palms fibers is studied and compared it with another material reinforced by glass fibers and then these two types of fibers combined together to make a hybrid composite material and also calculated the range of it's thermal conductivity [kahtan and ali, 2004]. materials and method . materials: there are two types of materials employed in this study: 1araldite resin (gy 260) with density of (1.15-1.2 g/cm 3 ) .this resin supplied from huntsman corporation. 2glass fibers s-type with density (2.6g/cm 3 ) . composite samples fabrication: hybrid composite araldite resin reinforced by chopped glass fibers can be fabricated by the hand lay up technique using laboratory compression molding machine. three types of samples were manufactured as follows : impact samples : the impact strength was determined using charby impact instrument conforming to (astm-e23) specification suitable to notch depth is (0.5mm) and notch base radius is (0.25mm). tensile strength samples: the standard dumb bell samples are cast according to (iso-r-527). compressive strength samples: these samples fabricated according to (astm-d790) standard as a rectangular shape(10mm×135mm) . thermal conductivity samples: these samples have a disc shape with (25 mm) diameter and (3 mm) thickness. determination of mechanical properties of composite: charpy impact instrument was used to evaluated the impact strength of composite material .the universal test instrument manufactured by (zhejinangtugong instrument co., ltd) was used to measure tensile strength with a (20kn) load . compressive strength can be measured by three point test by using universal hydraulic press (leybold harris no.36110) to calculate the maximum load exposed on middle of the sample . thermal conductivity test .heat conduction unit manufactured p.a. hilton ltd england was used in this test ,and fourier equation applied to calculate thermal conductivity coefficient (k). where: q = heat passed per time (w). k = thermal conductivity coefficient (w/m.ºc ) . a = area (m 2 ) . = temperature gradient ( ºc/m ). results & discussion figure1 shows the value of impact strength with fibers reinforcing percentage .generally ,the impact resistance considered low to the resins due to brittleness of these materials ,but after reinforcing it by fibers the impact resistance will be increased because the fibers will carry the maximum part of the impact energy which exposition on the composite material .all this will raise physical and thermal properties of fiber(s-type)-reinforced compositearaldite resin (gy 260) al-qadisiya journal for engineering sciences, vol. 5, no. 4, 341-346, year 2012 343 and improved this resistance .the impact resistance will continue to increase with increased of the fibers reinforcing percentage . the resin considered as brittle materials where its tensile strength is very low as shown in figure 2, but after reinforcing by fibers this property will be improved greatly ,where the fibers will withstand the maximum part of loads and by consequence will raise the strength of composite material .the tensile strength will be increased as the fibers percentage addition increased ,where these fibers will be distributed on large area in the resin as mentioned above ,the resin is brittle ,therefore its compressive strength will be low before reinforcement as shown in figure 3 .but after added the fibers to this resin the compressive strength will be raise to the producing material because the high modulus of elasticity of these fibers will helps to carry a large amount of loads and raise this strength. from figure 4 which represents the thermal conductivity with (80%) resin and (20%) glass fibers , we observed that increasing of (k) value when temperature increased due to good conducting ability of glass fibers compared with resins. figure 5 represents the thermal conductivity with (60%) resin and (40%) glass fibers ,thermal coefficient still increased with raising temperature, and we expect this increment because the high thermal coefficient of fibers . this behavior of increment will continue with (40%) resin and (60%) glass fibers as shown in figure 6. conclusions from the obtained results we get: low mechanical properties (impact, tensile, compressive strength) of the araldite resin .enhancement of mechanical properties after reinforcement by glass fibers .improvement of thermal coefficient when reinforcing by fibers .increasing thermal coefficient values with increased reinforcing percentage. references abbas a. al-jeebory, ali i. al-mosawi, “effect of percentage of fibers reinforcement on thermal and mechanical properties for polymeric composite material ” , aljournal of mechanical and materials engineering , first conference of engineering college , 2009 . ali i. al-mosawi “study of some mechanical properties for polymeric composite material reinforced by fibers ” , al-qadisiya journal for engineering science , vol. 2 , no 1 , 2009 . pp.14 – 24 . ali i.al-mosawi, haider k. ammash ,ali j. salaman “properties of composite materials data book” , 1 st edition ,misr-almurtadah inc .2011 . auter k.kaw “mechanics of composite materials”, 2 nd edition, taylor and francis group ,llc ,2006 . b.a.azhdar “impact fracture toughness of fiber reinforced epoxy resin” ,m.sc thesis ,u.o.t ,1992 . bogomolov v. and kartenko n. “thermal conductivity of the opalepoxy resin nanocomposite ” , physics of the solid state , vol 45,no 5,pp.957-960, 2003. e.p.degarmo, j.t. black, and r.a. kohser “materials and processes in manufacturing” , 10 th edition , john wiley & sons , 2008 . f.rondeaux , ph. bredy and j.m.rey. “thermal conductivity measurements of epoxy systems at low temperature” , cryogenic engineering conference (cec), usa, july 16-20, 2001 . mahmoud a.hassan 344 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 341-346, year 2012 g.dorey ,g.r.sidey and j.hutchings “impact properties of carbon fiber/kevlar 49 fiber hybrid composites” , composites 9 (january 1978) pp.25-32. g.morom ,e.drukkler ,a. weinberg ,and j.banbaji “impact behavior of carbon /kevlar hybrid composites” , composites ,vol 17 ,no 2 ,1986 .pp150-153. incropera ,f.p. and dewitt ,d.p. , 1996 “introduction to heat transfer”,3 rd edition, john wiley &sons. kahtan k.al-khazraji , ali i.al-mosawi “study of thermal behavior for composite material consisted from unsaturated polyester resin reinforced by palms and glass fibers” , journal of babylon university , engineering sciences , vol 9 , no 5 , pp.867 – 876, 2004. liyong tong ,adrian p.mouritz ,michael k.bannister “3d fiber reinforced polymer composites” ,elsevier science ltd ,first edition ,2002 . p.k. mallick “fiber-reinforced composites: materials, manufacturing, and design”, 3 rd edition , crc press, 2007 . raosathish u. and rodrigues l.l. raj , “applying wear maps in the optimization of machining parameters in drilling of polymer matrix composites – a review” , res.j.recent sci. 1(5), pp.75-82 ,2012 . figure1 impact strength reinforcing percentage (%) im p ac t s tr en g th ( k j/ m 2 ) 0 2 0 4 0 6 0 8 0 0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 physical and thermal properties of fiber(s-type)-reinforced compositearaldite resin (gy 260) al-qadisiya journal for engineering sciences, vol. 5, no. 4, 341-346, year 2012 345 figure 2 tensile strength reinforcing percentage (%) t e n si le s tr en g th ( n /m 2 ) 0 2 0 4 0 6 0 8 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 reinforcing percentage (%) c o m p re ss io n s tr en g th ( m p a) figure 3 compressive strength 0 2 0 4 0 6 0 8 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 t,(ºc) k ( w /m . ºc ) figure 4 reinforcing percentage ((80%) resin + (20%) fibers) 0 1 0 2 0 3 0 4 0 5 0 6 0 0 . 4 0 0 . 5 0 . 6 0 . 7 0 . 8 0 . 9 1 . 0 mahmoud a.hassan 346 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 341-346, year 2012 t,(ºc) k ( w /m . ºc ) figure 5 reinforcing percentage ((60%) resin + (40%) fibers) 0 1 0 2 0 3 0 4 0 5 0 6 0 1 . 5 1 . 6 1 . 7 1 . 8 1 . 9 k ( w /m . ºc ) t,(ºc) figure 6 reinforcing percentage ((40%) resin + (60%) fibers) 0 1 0 2 0 3 0 4 0 5 0 6 0 1 . 6 1 . 7 1 . 8 1 . 9 effect of annealing process on the corrosion resistance of aluminum alloy al-qadisiya journal for engineering sciences, vol. 5, no. 2, 123-128, year 2012 effect of annealing process on the corrosion resistance of aluminum alloy 2024-t3 asst.prof. khairia salman hassan1 asst. prof. dr. hani aziz ameen2 rahman ali hussain3 1 institute of technology – baghdad, mechanical department. 2 technical college / baghdad dies and tools engineering department. 3 technical college / baghdad dies and tools engineering department abstract the effect of annealing process on corrosion resistance for aluminum (2024-t3) alloy is investigated. samples of this alloy had been manufactured with dimensions (1.5*1.5*0.3) cm according to astm specifications. the annealing process applied by heating the metal in three deferent times; 270°c for two hours, 400°c for half hour and 350°c for one hour. after that the xray diffraction test has been done in order to know the phases resulted. the electrochemical corrosion test has been done by fixing the potential of the cell and changing it, the potential is chosen depending on open circle and comparing it with the standard metal potential of electrochemical series then adding 100 volt to show the cathode and anode behavior of metal, it had been found that the corrosion average resistance affected by temperature degree and time of the process, it had been noticed that increasing annealing temperature the corrosion resistance of alloy decreased, specially at 400°c, the heat treatment at the temperature 270°c was the best. keywords: annealing, corrosion, aluminum alloy. t3 -2024 تأثير عملية التلدين على مقاومة التاكل لسبيكة االلمنيوم 3 رحمن علي حسينم . م2هاني عزيز أمين. د.م. أ 1خيرية سلمان حسن . م.أ القسم الميكانيكي/ بغداد – معهد التكنولوجيا 1 القوالب والعدد قسم – بغداد/ الكلية التقنية 2 قسم القوالب والعدد–بغداد / الكلية التقنية 3 زــــــــــــــــلموجا اذ تـم تـصنيع t3 2024هدف الدراسة هو بيان تاثير عملية التلدين على مقاومة التاكل لسبيكة االلمنيـوم اجريت لها عملية تلـدين . astm وفق مواصفة الـ cm (0.3* 1.5* 1.5)ة بابعاد عينات من هذه السبيك من حيث تسخين المعدن الى درجة حرارة معينة ثم التبريد البطئ بالفرن حيث تم انتخـاب ثـالث درجـات لمدة ساعة واحـدة c°350 لمدة نصف ساعة، c°400 لمدة ساعتين، c°270حرارية وبثالث ازمان هي كـل آاجري اختبـار ت . لمعرفة االطوار الناتجة من العملية ) x-ray ( االشعة السينية اختبار بعدها اجري تم اختيار الجهد اعتماداً على دائرة مفتوحة ومقارنتهـا ه ، كهروكيميائي من حيث تثبيت جهد الخلية وتغيير فولت لبيان الـسلوك الكثـودي (100)بالجهد القياسي للمعدن من السلسلة الكهروكيميائية ثم تم اضافة مقدار بارتفـاع درجـة لوحظ انـه واالنودي للمعدن وقد وجد ان معدل التاكل يتاثر بدرجة حرارة وزمن العملية khairia salman hassan, hani aziz ameen and rahman ali hussain درجة مئوية وان المعاملة الحرارية 400حرارة التلدين تقل مقاومة السبيكة للتآكل خاصة المسخنة الى درجة .فضل اال درجة مئوية كانت 270عند درجة introduction annealing is a heat treatment used for changing the properties like rigidity and strength by heating the metal to a specified temperature degree and then cooling it slowly, the object of annealing is realizing the ductility and softness for metal and removing all internal stresses and making it homogeneous by fining the grains and improving cold forming properties. annealing had been done by spreading atoms in solid case until stability reached, where the heat takes place in spreading by providing the required energy for breaking the bounds, the atoms movement has an effect on the redistribution and breaking the extract existed in metal caused by forming that makes the plastic forming process more easy where the annealing role is decreasing the energy required for forming and removing the internal stresses which could be removed in room temperature degree for several metal types or could be done quickly by heating to a high temperature degree. the annealing could be done in three stages the first called recovering by removing the linear crystal defects and internal stress which is caused by these defects, this stage cover most of annealing stages. the second stage is recrystalization where the new crystals created to take the place of deformed crystals by internal stresses resulted from forming process. third stage is resulted from the higher temperature than recrystalizing temperature degree (rt) and run out time where the grains grows to course grains which affect the microscopic instruction of which decrease the mechanical properties. the (2024t3) aluminum alloy considered one from the high strength alloys which is used in many engineering applications which needs high strength like gears, rotating shafts, pins, valves, bolts, nuts and other parts of aircrafts and computer structures, this alloy distinguished by good corrosion resistance and could be improved by heat treatments (t8, t6) which could give more strength and stress and galvanic corrosion resistance. ming liu, 2008, studied the corrosion of commercial die-cast mg–al alloys was elucidated by a study, of the corrosion in 3% nacl, of (i) high-pressure die-cast (hpdc) model mg–al alloys, (ii) low-purity mg, (iii) high-purity (hp) mg and (iv) hp mg heat treated at 550 °c. in-joon son, 2009, studied the effect of equal-channel angular pressing (ecap) on the pitting corrosion resistance of anodized al-cu alloy was investigated by electrochemical techniques in a solution containing 0.2 mol/l alcl3 and also by surface analysis. the improvement of pitting corrosion resistance of anodized al-cu alloy processed by ecap appears to be attributed to a decrease in the size of precipitates, which act as origins of pitting corrosion. mohammad tajally,2009, presented a research reports comparative analysis of effects of cold working (cw) and annealing on tensile and impact-toughness behavior of 7075 al alloy. rahman a. hussain, 2002. studied the effect of different quenching mediums on hardness of (al –cu) alloy, the results show that the hardness changed according to type and cooling rate and this is due to the types and amounts of solid solution resulting from cooling process. c. scha¨fer, et. al. hence, prove that varying the heating rate the relative extent of various physical mechanisms (recrystallization, recovery, precipitation) can be strongly influenced. srihari kurukuri shows that on warm forming, three different aluminum alloys: al–mg alloy (aa5754) and al–mg–si alloys (aa 6016 and aa 6061) used in the automotive industry are considered. in the stretch forming with intermediate heat treatments, aerospace al–cu alloy (aa 2024) is considered. in non-heat treatable al–mg alloys, hardening is mainly due to the presence of solute atoms in solid solution and in heat treatable al–mg–si and alcu alloys, strengthening is determined by precipitates formed during ageing treatment.. k. van der walde et.al (2005) performed quantitative fractography on forty 2024-t3 sheet aluminum fatigue specimens. it was found that over half of the specimens analyzed had two or more crack-nucleating pits. the number of nucleating pits per specimen was found to be positively correlated with stress level and an interactive effect with corrosion exposure duration was observed. from the fatigue modeling efforts it is concluded that increased accuracy can be achieved by al-qadisiya journal for engineering sciences, vol. 5, no. 2, 123-128, year 2012 124 effect of annealing process on the corrosion resistance of aluminum alloy 2024t3 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 123-128, year 2012 125 incorporating multiple crack effects, particularly at higher stress levels where consistently unconservative life predictions can be avoided. al.th. kermanidis et.al (2005) prepared 2024 t351 aluminum alloy in bare, sheet form of 1.6 mm nominal thickness. machining of the specimens was made according to the specifications astm e 466-82 for the fatigue, astm e 647-93 for the fatigue crack growth and astm e 561-94 for the fracture toughness specimens. the effect of 36 h exposure to exfoliation corrosion solution of bare 2024 t351 aluminum specimens on the fatigue life of the specimens showed that the corrosion attack results in a significant drop of the materials fatigue life . metallographic corrosion characterization of specimens exposed to 17 exfoliation corrosion solutions for 24 h showed that the presence of corrosion pitting and inter-granular corrosion facilitates essentially the onset of fatigue cracks and, hence, reduces the fatigue life of the corroded specimens appreciably. in this research an experimental test had been applied to explain the effect of annealing on corrosion resistance for aluminum (2024-t3) alloy. experimental part 1-metal selection aluminum 2024-t3 alloy selected because it is used in many engineering applications like aircraft parts, the chemical analysis of it explained in table 1. 2preparation of test specimens the specimens are prepared from alloy sheets with (1.5*1.5*0.3) cm according to astm standard specifications to apply the corrosion test experiment. 3specimens classification after completing the preparation of specimens, it is classified as in table 2. 4heat treatments the annealing had been done for all specimen groups in table 2 where it is included heating to the mentioned temperatures and period of time. 5tests ax-ray diffraction test; applied on specimens mentioned in table 2 by using spectrometer, the results shown in table 3. bcorrosion test: electrochemical corrosion test had been done on all specimen in table 2 where the specimens represent the positive pole from a platinum in seawater solution as an electrolyte solution where the potential of cell fixed by open circuit (sami et al, 2005). the result’s value compared with the potential standard of the metal in electrochemical series, the potential hand been increased 100 volt to show the cathode and anode behavior for metal after current passing through it, figure 1 shows a picture of electrochemical cell. results and discussion 1results of electrochemical corrosion the microstructure of the alloy specimens is shown in figure 2. results of corrosion of alloy in different annealing temperatures are shown in table 4 and figure 3 shows the relation between current intensity and potential of electrochemical cell. khairia salman hassan, hani aziz ameen and rahman ali hussain the aluminum (2024-t3) alloy considered one from high strength alloys therefore it is used in many engineering applications like aircraft structures, so the applications of this alloy make it specified with specific properties such as hardness and strength in addition to corrosion resistance so this alloy has to be treated to improve its properties. the improvement may be by cold working or treated by isothermal processing. in this research annealing was the heat treating process applied to develop the corrosion resistance of this alloy. the results of electrochemical corrosion test show that the heating to (270°c) for two hours gave high corrosion resistance compared with the other tests, and this is because of the long period of time for heating which allows the alloy to take sufficient time for all phases to precipitate then gave the alloy a good mechanical and physical properties and this means a good corrosion resistance. conclusions 1by increasing annealing temperature, the corrosion resistance of alloy decreased specially at the 400°c. 2the original alloy without heat treatment gave good corrosion resistance. 3heat treatment at 270°c was the best temperature. references [1] ming liu " calculated phase diagrams and the corrosion of die-cast mg–al alloys ", 2008. [2] in-joon son " effect of equal-channel angular pressing on pitting corrosion resistance of anodized aluminum-copper alloy", 2009. [3] mohammad tajally " a comparative analysis of tensile and impact-toughness behavior of coldworked and annealed 7075 aluminum alloy",2009. [4] sami a. ajeel, jamal ibrahim hussein & talib mohamed “improvement of corrosion resistance for carbon steel alloy (st-52) used in marine environment”, eng. & technology, vol. 24, no.3, 2005. [5] rahman a. hussain, “the effect of cooling mediums on the brinel hardness of (al – cu) alloy, 1st. international congress of mechanics constantine faculty of engineering department of mechanical engineering, university of constantine , algeria 14-16 december 2002. [6] c. scha¨fer , v. mohles, g. gottstein ,”modeling of non-isothermal annealing: interaction of recrystallization, recovery, and precipitation”,acta materialia 59 (2011) 6574–6587, published by elsevier ltd [7] srihari kurukuri,”simulation of thermally assisted forming ofaluminum sheet”, ipskamp drukkers, 2010, india. [8] k. van der walde et.al, localized corrosion of 7xxx-t7 aluminum alloys in chloride media, ,technical contribution to the xxst international congress of the abm, january 24-27th 2007, rio de janeiro – rj – brazil. [9] al.th. kermanidis et.al ,”fatigue and damage tolerance behaviour of corroded 2024 t351 aircraft aluminum alloy”, journal of theoretical and applied fracture mechanics 43 (2005) 121– 132), 2005. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 123-128, year 2012 126 effect of annealing process on the corrosion resistance of aluminum alloy 2024t3 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 123-128, year 2012 127 table 1 chemical analysis of used alloy elements cu mg mn fe si zn cr ti al rem actual 4.4 1.5 0.6 0.3 0.4 0.1 0.05 0 92.6 standard 3.8-4.9 1.21.8 0.300.9 00.50 00.50 00.25 0-0.1 00.15 table 2 classification test specimens specimen symbol the case a metal without heat treatment b metal treated to 400°c for one hour c metal treated to 350°c for half an hour d metal treated to 270°c for two hours table 3 phases resulted from annealing process the phase specimen symbol alcu+al4cu9b alcu4+alcu3 c alcu+alcu4 d table 4 results of corrosion alloy in different annealing temperature. figure 1 the electrochemical cell. khairia salman hassan, hani aziz ameen and rahman ali hussain (b-group) (c-group) (d-group) figure 2 pictures of electrochemical corrosion for different annealing temperatures. figure 3 relation between current intensity and potential cell. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 123-128, year 2012 128 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 188 effect of soaking time on uniform density & resilient modulus dr-riadh .a.abass al-muthana university abstract this research is directed to evaluate the relation ship between sub base resilient modulus (mr) with uniform dry density during testing; only the deformation in the central portion of the specimen is measured. it is noticed that the divided layer of sub base sample is affected by the period of soaking and reflects this effect on the ( mr ) of the material .in this research ,the samples from the nibaee quarry were took. these samples were representing the lower limit of gradation of the specification. the specimens were classified into two groups. the first one is soaked for a period of two days and the second group was soaked for four days. على آثافة الحصى الخابط ومعامل الرجوعيةثير فترة الغمر تا رياض عبد الرضا الغرة. د جامعة المثنى الخالصة يد مع تحد للحصى الخابطوالكثافة الجافة ) mr( دراسة تقييم العالقة بين معامل الرجوعية هذا البحث تم في وفي هذا . للنموذج وهذا تم مالحظته في الطبقات المختلفة الغمر المختلفة على معامل الرجوعيةتأثير فترات وقسمت , للمواصفة في التدرج الدنياالنباعي وكانت هذه النماذج تمثل الحدود من مقالع تم أخذ نماذج ثالبح غمرت لماء لفترة يومين والمجموعة الثانية غمرت في اوكانت المجموعة األولى , مجموعتينإلى جماذالن .ربعة أيام أل al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 189 nomenclature mr = resilient modules. σ3 = minor principal stress. σa = deviator stress. θ = principal stress. introduction: the use of locally available material in a road construction is one of the most important aspects for minimizing the construction cost. the properties of these materials are essential for proper designs and construction of roads. the resilient modulus of unbound materials as determined by repeated triaxial load tests, the density of the specimen is important parameter. bowles (1979) defined the resilient modulus as the initial tangent modulus of a triaxial test stressstrain curve which has been cycled several times with a deviator stress. donald. m.c, (1984) stated that pavement systems ( roads, airfields, railways) which subject to traffic, soil, deposits, and soils beneath offshore structures subject to earth quake and wave loading are all classical examples were the soils will experience varying degrees principle stress rotation. mamlouck m.s & daves t.g, (1985) stated that the stress – strain relation of isotropic elastic materials in classical formulation expressed in terms fundamental parameters (e.g. young’s modulus and poisons ratio.) . but in highway engineering it is common to define stats dependent parameters are often used to interpret the non-liner and time-dependent response of pavement materials. correlation of ( mr) with uniform density: according to nordic road and transport research no.2 (1997), the resilient modulus of unbounded material as determined by repeated load triaxial testes, the density of the specimen is an important parameter. during testing, only the deformation in the central portion of the specimen varies significantly the overall density may not be the same as the density of the mid-section, and an incorrect relationship between density and resilient modulus may be obtained. therefore, method for measuring the density gradients has been developed to ensure uniform specimens. in this study, the deformation in the central portion of the specimen was measured. if the density within the specimen varies significantly, the overall density may not be the same as that in the midsection. an incorrect relationship between density and resilient modulus may be obtained; therefore, a method for measuring the density gradients has been developed to overcome this situation. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 190 in this test, the fact that the specimens compacted from the center outwards by static compaction is that it is difficult to obtain a uniform density gradient, and this may affect the resilient modulus measured in the traxial test. experimental work: this study deals with the effect of properties of sub-base materials from alnibaee quarry, and the durability properties of these materials on life of roads. to study the effect of distribution of moisture content along the height of specimen. the sample was divided into four portions through its height, to study the effect of soaking for periods 2 and 4 days, so specimens were classified into two groups. the first one is soaked for a period of two days and the second group was soaked for four days. at the end of these periods the specimens are compacted in four layers. the effect of the soaking period on the relation-ship between the resilient modulus (mr) and the value of the cbr and the dry density was examined. the moisture content is measured with (astm t 180). the gradation of the specimens was as specified by the upper and lower limits of sorb specification for sub-base materials as shown in fig.( 1 ) . during testing, only the deformation in the central portion of the specimen was measured. if the density within the specimen varies significantly, the overall density may not by the same as that in the mid-section. in this test, the specimens compacted from the center outwards by static compaction were found to be difficult to obtain a uniform density gradient, and this may affect the resilient modulus measured in the triaxial test. analysis of results: these materials are some-times not suitable for use, as they do not satisfy the allowable limitation of specifications such as strength requirements. o’flaherty (1988), stated that cbr is an empirical test and depends upon condition of the material at the time of testing. this means that soil must be tested in a condition that is critical to the design. the factor’s affecting the design such as soil type, dry density and other factors are relevant to the soil condition. it is noticed, that the value of cbr for soaking period of 2 days is more than the value of cbr for soaking 4 days, this may be due to the residual strength that soil still posses. but for fine gradation, it is noticed that the condition will be inversely due to the effect of fine particles that increased the value of cbr. the specimen was divided into four portions through its height, as shown fig.( 2 ). it was found that dry density increases in the middle portion than other portions (upper & lower), this happens due to it’s far away from the direct touches of water during soaking period. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 191 also it could be noticed that the dry density in the period of soaking for 2 days is less in value than for 4 days soaking, this was because of the increase of moisture content. from fig.( 2) the specimen is most dense in the second and third layers, this may be due to the compaction process for each layer. while the permeability to the sample according to the oldness of the mould affects the density of the sample. fig.(1) shows the above mentioned relationship for the two soaking periods (2 and 4 days). for the relationships shown in these figures, it is a fact that increasing the cbr value or the only density would cause an increase in the resilient modulus. fig.( 3 , 4) indicate that for the same cbr value soaking the specimens for 4 days would lead to decrease the mr value. this could be attributed to the increase of the pore water pressure inside the specimen for longer soaking period .the pore water would develop higher reaction against loading than the case of 2 days soaking due to higher saturation degree. from figures above, the relationship between cbr and mr is best described by a nonlinear equation. however, for the relationship between dry density and ( mr ), it seems that the soaking period has no distinguished effect on the value of (mr), as shown in fig. (5 & 6) this may be explained by the fact that the average density for the all height of the specimen does not depend much on the soaking period. conclusions: through out this study, and according to the results obtained from the experimental work, which was carried out on sub-base material loads to the following conclusions can be drawn: 1the value of resilient modulus gives good guide for evaluating sub-base material and can be taken instead of cbr value in specifications. 2 the relation between resilient modulus and deviator stress could be taken into consideration for acceptance each type of sub-base material. 3it was found that adopting values of cbr for period of soaking of two days gives reasonable results, which could be depend on. 4it was observed that, the saturation degree for the period of soaking of two days almost reaches to the optimum saturation more than other soaking periods. 5there is a relation between dry density of different layers of cbr molds and resilient modulus. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 192 reference: 1american association of state highway and transportation officials (aashto), ” standard specification for transportation materials and method of sampling and testing” (1982). 2bowels j. e, “ physical and geometrical properties of soils “ , m.c. graw hill book co. (1979 ) 3donald m.c, department of civil engineering queen’s university, ont. canada k7 l3 n6, february 1984. 4mamlouck m.s.&davies t.g, “ theoretical response of multi layer pavement systems. to dynamic non – destructive testing “, transportation research board, record no. 1022, (1985). 5nordic – road and transport research “uniform density gradients in soil specimens “ (1997). 6o’flaherty c.a. “highway engineering” “vol.2, 3rd edition, edward arnold, london, “(1988). al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 193 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 194 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 195 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٤ production of self compacting concrete for civil engineering structures abstract during the last decades new cementations materials were available, that led to new types of concrete. this represent a sort of technical revolution with respect to the traditional concrete. in this paper atraditional concrete (slump 170mm & little bleeding) , and two self compacting concrete( slump flow 700mm &neglectful bleeding) mixes were manufactured, ordinary portland cement content(400kg/m3) and w/c ratio 0.45 used in manufacturing concretes, in order to obtain the same 28 day compressive strength .scc were made with different types of mineral additions as fillers ,in this paper ground limestone and very fine sand used. the concrete specimens were wet cured at room temperature till the test age. compressive strength of scc were higher than that of the traditional concrete ,this can be related with a change in the microstructure of the cement matrix caused by the small particles of the limestone and very fine sand, which increase the density of cement paste and reduce the voids in it. key words: concrete, self compacting concrete, new concrete materials ,limestone, super-plasticizer, fine sand. ذاتیة الرص لمنشات الهندسة المدنیة خرسانةإنتاج نهاد طارق خشین علیاء مریح محمد الرضا عباس ریاض عبد مدرس مساعد مدرس مساعد مساعد أستاذ كلیة -جامعة بغداد كلیة الهندسة جامعة بغداد كلیة الهندسة -المثنىجامعة الهندسة الخالصة لقد تواجدت خالل العقود السابقة مواد إسمنتیة جدیدة أدت إلى ظهور أنواع جدیدة من الخرسانة وهذا یمثل إن. إلى الخرسانة التقلیدیة" نوع من الثورة التقنیة قیاسا . أهم أنوع الخرسانة المبتكرة هي خرسانة ذاتیة الرص من خرسانة ذاتیة الرص إلى نوع خاص من خلیط الخرسانة یتمیز بالمقاومة العالیة لالنعزال والذي یشیر مصطلح dr.riyad a. abass college of engineering al-muthena university alyaa m.mohammed college of engineering baghdad university nihad t.khshain college of engineering baghdad university al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٥ حیث . إن الخرسانة ذاتیة الرص تحد من الحاجة إلى الرج الداخلي والخارجي. یمكن إن یصب بدون رص أو رج تكتل حیث یمكن إن تكون أنها تجري بحریة في داخل وحول التسلیح الكثیف وتملئ القالب بشكل كامل بدون أي في هذا . أخرى عندما یكون الرص غیر مالئم ةمادة مثالیة للصب ألموقعي للركائز واألسس ومنشآت خرسانی جریان الهطول (و نوعین من خرسانة ذاتیة الرص ) ملم ونضوح قلیل١٧٠هطول (تم عمل خرسانة تقلیدیة البحث من % ٤٥سمنت /متر مكعب ونسبة ماء/كغم ٤٠٠نت خلطت باستخدام محتوى سم) ملم و نضوح مهمل ٧٠٠ یستخدم في عمل خرسانة ذاتیة الرص أنواع عدیدة من . یوم ٢٨اجل الحصول على نفس المقاومة بعمر عولجت عینات الخرسانة . في هذا البحث استخدم حجر كلسي مطحون ورمل ناعم جدا. المضافان كمالئات تم دراسة مقاومة انضغاط الخرسانة ذاتیة الرص . حین عمر الفحصمعالجة رطبة في درجة حرارة الغرفة إلى وهذا یر جع للتغیر الحاصل في هیكل بنیة ةباستخدام المواد المدرجة أعاله فكانت اكبر من الخرسانة االعتیادی و التي زادت من كثافة عجینة "عجینة االسمنت بسبب الحبیبات الصغیرة للحجر الكلسي والرمل الناعم جدا . سمنت وقللت الفراغات فیهااال introduction the most important innovative concrete is self-compacting concrete (scc), the term self-compacting concrete (scc) refers to a special type of concrete mixture characterized by high resistance to segregation, that can be cast without compaction or vibration. scc eliminates the need for internal or external vibration, as it freely flows in and around dense reinforcement and fills the mold completely without any blockages. it would be an ideal material for casting in situ piles, foundations, and other concrete constructions where compaction is infeasible. concrete is the most widely consumed material in the world, after water. placing the fresh concrete requires operatives using slow, heavy, noisy ,expensive, energy consuming mechanical vibration to adequate compaction to obtain the full strength and durability of hardened concrete[european union growth , 2005]. for several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest in japan. to make durable concrete structures, sufficient compaction by skilled workers is required. however, the gradual reduction in the number of skilled workers in japan's construction industry has led to a similar reduction in the quality of construction work [collepardi,2002]. one solution for the achievement of durable concrete structures independent of the quality of construction work is the employment of self-compacting concrete, which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. the necessity of this type of concrete was proposed by okamura in 1986,studies to develop self-compacting concrete, al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٦ including a fundamental study on the workability of concrete, were carried out by ozawa and maekawa at the university of tokyo [collepardi,2002]. the prototype of self-compacting concrete was first completed in 1988 using materials already on the market. self compacting concrete (scc), which have been developed and exploited over the past one a half decades eliminates the need for slow, heavy, noisy ,expensive ,energy-consuming and often dangerous mechanical vibration to compact the fresh concrete. in structural members with high percentage of reinforcement it fills also completely voids and gaps. it flows like “honey “and has nearly a horizontal concrete level after placing. self compacting concrete is defined so that no additional inner or outer vibration is necessary for the compaction. scc is compacting it self alone due to its weight and deaerated almost completely while flowing in the formwork[shah,2005]. environmentally friendly (scc) could be produced and used , with benefits to the construction process to the workers, and to people living near construction sites. with respect to the traditional concretes, the new cementations materials, thanks to the availability of new raw materials, allow the concretes to reach much higher performances in terms of execution on job sites, useful service life, and mechanical strength these new raw materials include: • new synthetic polymers (poly-acrylates) which, with respect to naphthaleneor melamine-sulphonated polymers, are able to reduce even more effectively the amount of mixing water and then the water-cement ratio with all the consequent benefits [corinaldesi,orlandi and moriconi,2002] • viscosity modifying agents based on welan gum to produce thixotropic mixes and then to obtain cohesive fresh concretes even when very fluid [european union growth,2005] • polymeric metallic fibers to increase the ductility and the fracture energy of concretes which usually are brittle materials [corinaldesi,orlandi and moriconi,2002] • mineral additions characterized by amorphous silica such as silica fume (waste from silicium-iron alloys) in form of very fine particles (size of some nm/m) or ufacs al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٧ (ultra-fine amorphous colloidad silica) synthetically produced in form of particles (size of some nm). with regard to its composition, self-compacting concrete consists of the same components as conventionally vibrated normal concrete, which are cement, aggregates, water, additives and admixtures. however, the high amount of superplasticizer for reduction of the liquid limit and for better workability, the high powder content as “lubricant” for the coarse aggregates, as well as the use of viscosity-agents to increase the viscosity of the concrete have to be taken into account. in principle, the properties of the fresh and hardened scc, which depend on the mix design, should not be different from normal concrete . one exception is only the consistency. self-compacting concrete should have a slump flow s>65cm. the present procedure for the production of self-compacting concrete is predominantly empirical. the mix design is based on experience from japan, the netherlands, france and sweden. for the production of scc, the mix design should be performed so, that the predefined properties of the fresh and hardened concrete are reached for sure. the components shall be coordinated one by one so that segregation, bleeding and sedimentation is prevented [european union growth,2005]. the most important basic principle for flowing and cohesive concretes including scc is the use of super plasticizer combined with a relatively high content of powder materials in terms of portland cement, mineral additions, ground filler and/or very fine sand. since the development of the prototype of self-compacting concrete in 1988, the use of self compacting concrete in actual structures has gradually increased. the main reasons for the employment of self-compacting concrete can be summarized as follows: · to shorten construction period. · to assure compaction in the structure: especially in confined zones where vibrating compaction is difficult. · to eliminate noise due to vibration: this is effective especially at concrete products plants. that means the current condition of self compacting concrete is a “special concrete” rather than standard concrete. currently, the percentage of self compacting concrete in al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٨ annual product of ready mixed concrete in japan is around 0.1% [okamura and ouchi,1999] . a typical application example of self-compacting concrete is the two anchorages of akashi-kaikyo(straits) bridge opened in april 1998, a suspension bridge with the longest span in the world (1,991 meters) [okamura and ozawa,1995]. one of the key obstacles preventing a faster and wider use of scc in europe was the absence of suitable test methods to identify its three key fresh properties: filling ability, passing ability and resistance to segregation. this was hindering the increased use of scc [european union growth,2005]. experimental work the most important basic principle for flowing and unsegregable concretes including scc is the use of the super plasticizer combined with a relatively high content of powder materials in term of portland cement , mineral addition , ground filler and/or very fine sand. a partial replacement of portland cement by fly ash was soon realized to be the most compromise in terms of rheological properties, resistance to segregations, strength level, and crack freedom. some other alternative to fly ash , have been considered in the present paper, they are very fine sand and ground limestone. two compacting concretes were manufactured using very fine sand (fscc), and limestone(lscc), in addition to the traditional concrete (tc). the following tables (1,2,3) show the composition of each type of concrete. tables (a-c)show the properties of materials that used in this research. figure (1) shows the percentage of fine particles for traditional concrete and self compact concrete, it is clear that the percentage of fine particles of self compacting concrete is higher than that for traditional concrete, which represent one of most important criteria of scc. slump test for tc was made according to astm c143-99, and the slump flow for scc was made using the cone of the slump test , by measuring the diameter of concrete circle after lifting the filled cone with concrete. bleeding of concrete was measured using the test described by astmc232-99. concretes were casted into al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٩ 15*15*15cm cub without any compacting or vibration for scc ,and with compacting for tc. all concrete cubes were wet till the age of testing. disussion of results table(4) describes the properties of fresh concrete for self-compacting concrete. self compacting concrete with very fine sand shows slump flow of 650mm after 30 minute less than the self compacting concrete with limestone which shows slump flow of 700mm after 30minut, in addition the segregation for fscc could be described as fair comparing to no or legible segregation for lscc . figure (2)shows the bleeding capacity as a function of the slump level fortraditional concrete (tc) with a cement factor 400 kg/m3 in the absence of superplasticizer. the slump was increased by increased the amount of mixing water. when the slump is over 175 mm the bleeding increases too much and this was the reason why aci in 1973 did not recommend slump higher than 175 mm . with the advent of super plasticizers, scc concretes with slump flow up to 700 mm were manufactured with no or negligible bleeding provided that an adequate cement factor was used. the self compacting concrete (fscc),and (lscc)show no or legible bleeding as shown figure (3). figure (4) describe the compressive strength of (tc) ,(fscc) and(lscc) it is clear that the compressive strength of self compacting concrete was higher than the compressive strength of traditional concrete . that because using super plasticizer which led to reduce the mixing water ,the reduction of water lead to increase of the compressive strength. in addition the use of fine particles of (fine sand &limestone) led to reduce the voids in the mix and make it strong. in addition the compressive strength of( lscc) was higher than the strength of (fscc), that because, the fine particles of limestone are more effective than the particles of very fine sand. conclusions 1. the results obtained in the present paper show the extra-ordinary properties which can be obtained by using the innovative concretes recently developed in the field of scc. scc appears to be very successful because it is easy to place in a safe way independent of the quality and reliability of the workmanship available today on the jobsites. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٠ 2. the high-strength scc studied in this paper can be considered as particularly suitable in the field of civil engineering. 3. the combined use of cement type i (400kg/m3), super plasticizer (1.1-1.5%), limestone or very fine sand (130-160 kg/m3), and aggregate with a maximum size of 20 mm allow the manufacture of self-compacting concretes suitable for concrete structures. 4. the most important progress achievable in the future for scc technology depends on the availability and use of some new ingredients such as: a) powder materials including (recycled aggregate from demolished concrete , etc.). b) more effective super plasticizers those based on acrylic polymers. c) viscosity modifying admixtures based on organic polymers and ultra fine amorphous colloidal silica. references 1final report september ,2005 ,”measurement of properties of fresh selfcompacting concrete “,european union growth contract no. g6rd-ct-20010580. 2 m.collepardi, 2002 ,"self copacting concrete : what is new"pp.3-8. 3surendra p. shah ,2005, “proceedings of the fourth international rilem symposium on selfcompacting concrete” . 4v. corinaldesi, g. orlandi, g. moriconi,2002, «self-compacting concrete incorporating recycled aggregate», proceedings of the international conference "challenges in concrete construction innovations and developments in concrete materials and construction", dundee,scotland, uk, 9-11 september 2002, pp. 455 – 464. 5okamura, h. and ouchi, m., 1999, "self-compacting concrete-development, present and future", proceedings of the first international rilem symposium on self-compacting concrete, pp. 3-14. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥١ 6okamura, h. and ozawa,k.,1995, "mix design for self compacting concrete", concrete library of jsce, no.25, june, 1995, pp107-120.pp.4-16 7frank dehn, kluse, h., and driek, w.,2002," self compacting concrete time development of the material properties and bond behavior" pp.10-17 8astm stander c143 “ test method of slump test”1999. 9astm stander c232 “standard test methods for bleeding of concrete”1999. table (1) the composition of traditional concrete (tc) ingredients kg/m3 ordinary portland cement type i 400 coarse aggregate 20-5mm 1040 fine aggregate zone 2 760 water 180 w/c 0.45 table (2) the composition of self compacting concrete with very fine sand(fscc): ingredients kg/m3 ordinary portland cement type i 400 coarse aggregate 9.5-20mm 875 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٢ 5-9.5mm 440 fine sand zone 2 very fine sand 0.075-0.6mm 430 100 limestone water 180 w/c 0.45 super plasticizer 9.6 table (3) the composition of self compacting concrete with limestone (lscc): properties fscc lscc specific mass kg/m3 2350 2400 slump flow mm after: 0 min. 30 min. 60min. 680 650 620 740 700 680 concrete aspect (segregation) cohesive (fair) cohesive (no) table (4) the fresh concrete properties of self compacting concrete ingredients kg/m3 ordinary portland cement type i 400 coarse aggregate 9.5-20mm 5-9.5mm 875 440 fine aggregate zone 2 limestone 0.15-0.6mm 430 180 water 180 w/c 0.45 super plasticizer 8.6 table (a) chemical analysis of cement al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٣ table (b) physical properties of cement oxides content % cao sio2 mgo fe2o3 al2o3 so3 l.o.i 61.5 19.6 2.78 3.9 5.52 2.01 2.95 compounds c3s 54.34 c2s 15.00 c3a 8.2 c4af 11.55 properties results ios no.5/1984 fineness(blaine)m2/kg 235 >230 initial setting time 1:55 >0:45 min. final setting time 4:00 <10:00 hours compressive strength 3days 19.92 >15 n/mm2 compressive strength 7 days 26.4 >23 n/mm2 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٤ table (c) the properties of aggregate and limestone properties coarse aggregate sand limestone specific gravity 2.63 2.53 2.69 so3% 0.09 0.19 bulk density kg/m3 1637 1590 1700 fineness modulus 2.86 absorption 0.6 0.9 0.8 figure (1) particle size distribution of the aggregate in ssc and tc. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٥ figure (2) bleeding capacity*104. as a function of slump for traditional concrete. figure (3) bleeding capacity *104 as a function of slump for self compacting concrete. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٦ figure (4) development of compressive strength with time for traditional concrete(tc) and for self compacting concrete with very fine sand(fscc) and with limestone(lscc). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 64 investigating the productive energy and the number of revs of a small wind turbine at a variable wind speeds. noor m. jasim mechanical engineering dept. university of kufa abstract: in this research , the dynamics of the wind energy conversion system of a small wind turbine is studied. the aerodynamic forces are estimated at any incoming wind speeds for turbine blade which is known as airfoil section (naca4412). the scheme is simulated by a program of fortran90 and results are presented . the torque and the productive power are estimated from this program at each incoming wind speed, these results are compared with the extraction power from betz theorem . also, the number of revs of the small turbine are estimated at each incoming wind speed. from this model, we can specified the determinism of tip speed ratio and wind speed are a more suiting . because wind speed increase over the suitable value, causes increasing of vortices of the hub and the tip and other losses . the proposed model can further investigate for analysis, design and performance evaluation of remote and off-grid wind energy conversion systems in hybrid applications. keywords: wind energy, renewable energy, aerodynamics, small wind turbine, (cst), torque ,the productive power ,the blade design and tsr. ..دراسة الطاقة المنتجة وعدد دورات توربین ریاح صغیر في سرع ریاح مختلفةدراسة الطاقة المنتجة وعدد دورات توربین ریاح صغیر في سرع ریاح مختلفة نور محسن جاسمنور محسن جاسم. . مم..مم قسم الھندسة المیكانیكیةقسم الھندسة المیكانیكیة سةسة كلیة الھند كلیة الھند––جامعة الكوفة جامعة الكوفة الخالصة ـ . التوربينية الصغيرة في المنظومات في هذا البحث تم دراسة ديناميكية نظام تحويل طاقة الرياح وى الديناميكيـة الق وذلـك مـن . (naca4412) لريشة التوربين ذو المقطع االنسيابي المعروف ب داخلة سرعة هواء الهوائية تم حسابها ألي الطاقة الناتجة من التـوربين و قيمة عزم التدوير أن . بلغة الفورتران لحساب كافة النتائج المطلوبة برنامج محاكاة خالل اعداد النتائج مع الطاقة الممتصة من الرياح حيث قورنت , تكون محسوبة بواسطة هذا البرنامج لكل سرعة رياح داخلة إلى التوربين من خالل هذا النموذج يمكننا تحديد نسبة . ات التوربينرب عدد دوكذلك تم حسا. betz theoremبيتز المحسوبة من نظرية فـان خـسائر على القيمة المناسـبة عندما تزداد سرعة الرياح . وسرعة الرياح التصميمية األكثر مالئمة الريشة سرعة طرف .جذرها تزداد أيضاًودوامات طرف الريشة وتقييم األداء وتصميم أنظمة تحويل طاقة الريـاح البعيـدة وخـارج , للتحليل ألبعد من ذلك النموذج المقترح يمكن أن يتحرى .الشبكة في التطبيقات الهجينة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 65 nomenclature symbols description unit a swept rotor area m2 b number of blades c chord length m cb betz coefficient cl lift coefficient cd drag coefficient f1i the net force in the direction of rotation n f2i the net force in the direction of the undisturbed wind n h maximum camber of airfoil m i area moment of inertia of blade m4 im the mass moment of inertia of blade kg.m2 pmax the maximum productive power watt r radius of turbine at each section m r maximum radius of turbine m t the maximum thickness of airfoil, or the time m, sec t torque of turbine n.m tsr tip speed ratio vb the blade speed m/s vw incoming wind speed m/s vrel relative wind speed m/s zu(x), zl(x) function of the upper and lower surfaces of airfoil greek symbols symbols description unit α angle of attack degree β pitch angle degree ε camber to chord ratio , (h/c) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 66 λ tip speed ratio ф apparent wind angle, relative angle degree ρair air density kg/m3 ρb the density of blade per unit length kg/m2 τ thickness to chord ratio ,(t/c) ω angular speed of the rotor rad/sec introduction a wind turbine is a rotating machine which converts the kinetic energy of wind into mechanical energy. if the mechanical energy is then converted to electricity, the machine is also called in different name a wind generator, wind turbine, wind power unit (wpu), wind energy converter (wec).the amount of power a rotor extracts from the wind can be calculated with blade element momentum theory. the power is calculated from the rotor angular velocity and torque, which are found by solving system of nonlinear equations. the system of nonlinear equations must be solved iteratively with an equation solver. the three bladed rotor is the most important and most visible part of the wind turbine. it is through the rotor that the energy of the wind is transformed into mechanical energy that turns the main shaft of the wind turbine.[ michael,2007] many investigators have explored the small wind turbine using several methods to study ,analysis and modeling of the wind turbine conversion system. we can previewing these investigators and the works them , as shown below: khan and iqbal, (2003) , in this paper dynamics of a small wind energy conversion system is modeled and simulated. wind data generation with a flexible wind field model and the design of a fuzzy logic controller for optimum power extraction is included. simplified models representing rotor aerodynamics are used. control algorithm employs direct torque sensing and it adjusts rotor speed by changing the dump load. the scheme is simulated in matlab-simulinktm and results are presented. use of the proposed control algorithm removes the need for wind speed sensing with anemometers, provided a suitable torque estimation technique is available. simulation indicates that the effect of sudden wind speed variation is minimal on the performance of a well-designed fast responding small turbine. daniel m. (2009) , tested different blades with various angles. he did doing this in order to discern the most efficient blade design based on voltage output. the purpose of work was to find the most efficient set of blades based on the maximum voltage that could be produced. he predicted that the composition of the rotor blades would have little or no effect on the maximum voltage output ,but gather different inertia levels that have a noticeable effect on the number of seconds it takes the blades to get to a maximum, constant voltage output and the number of seconds of revolution after the wind source is turned off. by comparing four different readings, each with a different angle, you can derive a conclusion on which angle is most effective and why. this prediction is based on the fact that angles are limited in effectiveness based on the material and size of the blades it is tested on. he found that the lighter the material was, the stronger the voltage it would output in the first five seconds, and the weaker of a voltage five seconds after the wind source was cut off. it is vice versa for heavier blades. the reason that the blades would start up faster if they were made from lighter material is because the wind force has an easier time getting a al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 67 constant rpm started. this is because of the inertia, the ability of an object to store energy because of its mass. faizul and quamrul islam, [2008 ],drag and torque coefficients of a stationary five bladed vane type rotor have been investigated in this present research work by measuring the pressure distribution on the blade surfaces at various rotor angles. the experimental investigation has been performed at reynolds number 1.65 × 105 in a uniform flow jet produced by an open circuit wind tunnel. it has been observed that the total static torque coefficient increases from 00 to 100, and reaches its maximum value and then decreases up to 300. from this point, the total static torque increases up to 72°. total static torque coefficient at different rotor angles curve repeats from 720 to 1440, 1440 to 2160, 2160 to 2880, and 2880 to 3600 angle of rotation. a quasi-steady approach has been applied for the prediction of dynamic performance of the rotor using the static drag and torque coefficients. michael , [2007] , has been determined the optimal site of specific wind turbine design, which is the design that results in the lowest cost of energy at that particular site. there are many decisions that have to made in designing a modern wind turbine. the optimal wind turbine design for one location is not necessarily the optimal design for another location because the wind speed distribution may vary between locations. in addition, the turbine with the highest efficiency is not necessarily the optimal turbine. it is possible for a less efficient wind turbine to have a lower cost of energy. young ,and et.al ,[2007], they are under development of the prototype of 2 mw wind turbine with low speed gearbox. in this paper, the concept study for the type, the aerodynamic design for the blade and the details of load calculation will be presented. the detailed characteristics of the system will also be introduced. the rated capacity of kbp-2000m is 2000 kw with 3-blades at wind speed of 11.5 m/s and rotational speed of generator, 15.3 rpm. the power is to be produced in the range of wind speed of 3 to 25 m/s. the tip speed ratio (tsr) of rotor blade was selected as 8, in which power coefficient is 0.482, by compromising the dimensions of blades and generator with the problems related to rotational speed. the optimal tsr is maintained by torque control to get maximum wind energy under the rated wind speed. in partial load conditions under rated speed, the torque will be controlled by a predefined torque-speed curve . this torque-speed curve is chosen to achieve operation at the optimum tip speed ratio of the rotor. clifton-smith and wood, [2007], much work has been done to maximize the power extraction of wind turbine blades. however, small wind turbines are also required to be self starting and whilst blades designed for maximum power extraction can be optimized analytically, these blades often have poor starting performance. the numeric method of differential evolution is used here to maximize for both power and starting performance. standard blade element theory is used to calculate the power coefficient, and a modified blade element method for starting time. the chord and twist of each blade element make up the genes for evolution. starting times can be improved by a factor of 20 with only a small reduction in power coefficient. with the introduction of the tip speed ratio as an additional gene, up to 10% improvement in power coefficient was achieved. a second study was done in another case where analytical optimization is not possible; the inclusion of tip losses. the inclusion resulted in only a small increase in the optimum chord in the tip region which becomes less noticeable at lower tip speed ratios. aerodynamics: air flow over a stationary airfoil produces two forces, a lift force perpendicular to the air flow and a drag force in the opposite direction of the air flow , as shown in figure (1).the pressure difference across the airfoil surfaces yields the lift force. both the lift and the drag are proportional to the air density, the surface area of the airfoil, and the square of the wind speed. suppose now that we allow the airfoil to move in the direction of the lift force. this motion or rotation will combine with the motion of the air to produce a relative wind direction shown in figure (1). the airfoil has been reoriented to maintain a good lift to drag ratio. the lift is perpendicular to the air al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 68 flow but is not in the direction of airfoil rotation. the mathematics of lift and drag forces [gary,2001]: 2)2/( rela ir vacllift ρ= ( 1 ) 2)2/( rela ir vacddrag ρ= ( 2 ) where vrel is relative wind speed. the lift and drag forces can be split into components parallel and perpendicular to the air flow, and these components combined to form the net force f1 in the direction of rotation and the net force f2 in the direction of the air flow. the force f1 is available to do useful work. the force f2 must be used in the design of the airfoil supports to assure structural integrity. the way of using f1 is to connect three such airfoils or blades to a central hub and allow them to rotate around a horizontal axis, as shown in figure (3). the force f1 causes a torque which drives some load connected to the propeller. the tower must be strong enough to withstand the force f2. these forces and the overall performance of a wind turbine depend on the construction and orientation of the blades. one important parameter of a blade is the pitch angle β, which is the angle between the chord line of the blade and the plane of rotation, as shown in figure 1. the chord line is the straight line connecting the leading and trailing edges of an airfoil. the plane of rotation is the plane in which the blade tips lie as they rotate. the blade tips actually trace out a circle which lies on the plane of rotation. full power output would normally be obtained when the wind direction is perpendicular to the plane of rotation. the pitch angle β is depending only on the orientation of the blade. another important parameter of a blade is the relative angle ф , which is the angle between the relative wind speed of the blade and the plane of rotation , as shown in figure (1).these relations between the forces and angles, we can be regulate it in the equations below as the following φφ cossin1 iii dlf −= ( 3 ) φφ sincos2 iii dlf += ( 4 ) another important blade parameter is the angle of attack , which is the angle α between the chord line of the blade and the relative wind or the effective direction of air flow. it is a dynamic angle, depending on both the speed of the blade and the speed of the wind. the blade speed at a distance r from the hub and an angular velocity ωm is rωm. the lift and drag have optimum values for a single angle of attack so maintain a nearly constant angle of attack from hub to tip. a straight blade is easier and cheaper to build and the cost reduction may more than offset the loss in performance.[7] the aerodynamic profile the shape of the aerodynamic profile is decisive for blade performance. even minor alterations in the shape of the profile can greatly alter the power curve and noise level. therefore a blade designer does not merely outline the shape when designing a new blade. the shape must be chosen with great care on the basis of past experience. for this reason blade profiles were previously chosen from a widely used catalogue of airfoil profiles developed in wind tunnel research by naca.[ stiesdal,1999] blade design to create a blade design we need to specify the chord width and relative angle ф at each of a series of stations along the span of the blade. at each station we will create the right shape of the blade to produce the right loading (lift) for the bit of wind with which it will have to deal. the tip al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 69 speed ratio is the ratio between the speed of the wind and the speed of the tips of the blades of a wind turbine. high efficiency 3-blade-turbines have tip speed/wind speed ratios of 6 to 7. modern wind turbines are designed to spin at varying speeds (a consequence of their generator design). use of aluminum and composites in their blades has contributed to low rotational inertia, which means that newer wind turbines can accelerate quickly if the winds pick up, keeping the tip speed ratio more nearly constant. operating closer to their optimal tip speed ratio during energetic gusts of wind allows wind turbines to improve energy capture from sudden gusts that are typical in urban settings. in contrast, older style wind turbines were designed with heavier steel blades, which have higher inertia, and rotated at speeds governed by the ac frequency of the power lines. the high inertia buffered the changes in rotation speed and thus made power output more stable. [ david,2002] 1-setting the test blade angle. when design a wind turbine rotor ,the angle α will depend on the angle of the apparent wind φ ,and the pitch angle β .so we have control over α ,and thus control over the lift and drag produced by the blade .we shall need to optimize the lift force ,to satisfy the betz criterion, but the blade will not work well unless the drag is minimized. we can say that the relative angle ф should be set to give this angle of attack. to specify the pitch angle β , we need to know the relative angle ф at which the relative wind strikes the rotor plane.[ david,2002] ( 5 ) ( 6 ) 2-moment of inertia of airfoil sections the moment of inertia of the airfoil cross-sections about the axis x is then related only to the airfoil shape given by the upper and lower surfaces zu(x) and zℓ(x). as shown in figure (2), both the area (a) and the total moment of inertia i are the integrated contributions of all the infinitesimal rectangular sections, each dx wide and zu − zl tall. the inertia of each such section is appropriately taken about the neutral surface position defined for the entire cross section.[10] ( 7 ) ( 8 ) ( 9 ) these relations which is a good assumption if the x axis is parallel to the airfoil’s chord line. although equations (7) –(9) can be numerically evaluated for any given airfoil, this is unnecessarily cumbersome for preliminary design work, where both ( a ) and ( i ) are needed for possibly a very large number of candidate airfoils or wings .for the purpose of approximating ( a ) and ( i ), we first define the maximum thickness t, and maximum camber h, in terms of the upper and lower surface shapes. we also define the corresponding thickness and camber ratios τ and ε. [10] ( ) ( ){ }xzxzt lu −= max ( 10 ) ( ) ( )[ ]{ }2/max xzxzh lu += ( 11 ) ct /≡τ ( 12 ) ch /≡ε ( 13 ) αβφ +=       ∗ = − tsrr r 3 2 tan 1φ al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 70 examination of equation (7) indicates that ( a ) is proportional to (t and c), and examination of equation (9) indicates that ( i ) is proportional to [ c and t (t 2 + h2)]. this suggests estimating ( a ) and ( i ) with the following approximations [10]. ( 14 ) ( 15 ) ( 16 ) ( 17 ) the proportionality coefficient can be evaluated by equating the exact and approximate ( a) and (i) expressions above, e.g. [10]. ( 18 ) ( 19 ) 3-selecting blade chord and profile. the width of the blade is also called the blade chord. a good formula for computing this is: ( 20 ) many of the good profile data can be found in literatures of model airplane. we have chosen the naca 4412 profile. it is an effective profile with a good thickness, which makes the blade strong. in order to determine the lift coefficient, we must have a look at the profile curves. in order to determine the lift coefficient we must have a look at the profile curves. [david,2002] blade element momentum theory. the amount of rotor power which extracts from the wind can be calculated with blade element momentum theory. the power is calculated from the rotor angular velocity and torque, which are found by solving system of nonlinear equations. these equations are derived from two different approaches to calculating power. the first approach determines the power from lift and drag on the rotor blades. the second approach determines power from a momentum balance. dynamic modeling 1wind field investigation of wind turbine performance require a realistic set of wind data with durations ranging form minutes to hours. we assumed the constant the incoming wind speed for calculation of torque and the power . at each station we will create the right shape of blade to produce the right loading lift for bit of wind with which it will have to deal with. the bit of the blade at radius r sweeps a fraction of the total swept area and has the job of slowing this bit of wind down by the right amount to satisfy the betz criterion ,see figure (3). the apparent wind which a blade is altered by it 's own speed through the air. the rotational wind speed adds to the incoming wind speed to give the relative wind speed which creates the lift and drag forces. [khan and iqbal,2003]. ( ) ( )22re rowl vvv += ( 21 ) vro is the blade speed at a distance r from the hub and an angular velocity ω is : vro= r ω ( 22 ) ( ) ( )( )φ φ tan cos 793.2 2 2 dl ccrtsrb r c +∗ = al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 71 2aerodynamics forces: the aerodynamics forces (lift and drag forces) depend on the coefficients cl and cd, which in turn depend on the cross section of blade we are using and on the angle α at which the wind strikes the blades. the lift and drag coefficients are obtained from tables. these are experimentally measured in wind tunnels and recorded. for the naca 4412 this point of contact is where cl is about (0.933) degrees and cd is about (0.037) at α is about 8 degrees and low reynolds number [khan and iqbal,2003]: the lift and drag forces of the aerofoil are estimated from equations ( 1 and 2) respectively. 3torque & thrust by lift & drag the power is calculated from the rotor angular velocity and torque, which are found by solving system of nonlinear equations ( 1 & 2 ) ,these forces effecting on the airfoil sections of the blade from the hub to the tip, as shown in figure (3) and equations ( 3 and 4 ).[ michael,2007] a practical way of using f1 is to connect three blades to a central hub and allow them to rotate around a horizontal axis. the force f1 causes a torque which drives some load connected to the propeller along the blade from the hub to the tip: ( )2/1 drrft ii +×= ( 23 ) where ti is the torque due to the wind speed at each station on the blade .the summation of the above torque along the blade represent the torque for the one blade. the total torque is the summation of all the torque of blades at the wind turbine for any the incoming wind speed . we assume the wind turbine design consists of three blade . therefore; total torque, ( t ) =3 x ∑ti ( 24 ) 4-determination of rotor speed for determining the rotor speed from an estimated the rotor torque could be established from the basic principles of wind energy engineering. the turbine torque tj+1 must be opposed by an equal and opposite load torque tj for the turbine to operate at a steady rotational speed. if t j+1 is greater than tj , the turbine will accelerate, while if tj+1 is less than tj the turbine will decelerate. the mathematical relationship describing this is: dt d itt mjj ω +=+1 ( 25 ) where, im is the mass moment of inertia of the turbine, all referred to the turbine shaft. ii bm ×= ρ ( 26 ) dt dω is angular acceleration of the turbine . since the acceleration is ( dω/dt ) , we can determine that the angular velocity of the turbine must increase linearly with time until the turbine reaches its rated angular velocity . dt i tt d m jj       − = +1ω (27) 5estimated power. the maximum productive power from wind pmax could be found by multiplying maximum torque tmax with rotor speed, ω for any incoming wind speed: ω×= maxmax tp ( 28 ) we can be calculate the power and the revolution of the rotor for the wind turbine for any incoming wind speed by using the computer program. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 72 6-determination of tip speed ratio: the tip speed ratio (tsr) λ is a measure of the rotor’s rotational speed at any given wind speed, where , (tsr) λ =(tip speed of blade)/(incoming wind speed). wv r tsr ω× = ( 29 ) results and discussion : fortran power station program is used for simulating the models ,the flow chart of the mathematical model programming as shown in the figure ( 4 ). the inputs to the model are an incoming wind speed, aerodynamic coefficients ( lift and drag ) of the airfoil for naca-4412 , the airfoil section with all dimensions ,angle of attack α, which is constant for all values of "r" , the relative angle ф and pitch angle β at each station and rotor diameter, see table ( 1 ) [humaid and ali,2005]. the outputs of the program model are revealed in the table ( 2 ) . figure ( 5 ) shows the aerodynamic maximum torque compare with the startup aerodynamic torque at any incoming wind speed. as the incoming wind speed increase , the lift forces increase ,along the blades from hub to tip, consequently the maximum torque increase, also the startup torque increase with increase the incoming wind speed at startup which prevailing the mass moment of inertia of blades. the maximum power produce by torque element compare with betz coefficient theorem are presented as a function of the incoming wind speed in figure ( 6 ).the power produce by betz coefficient theorem is estimated from the below equation[gary,2001]: power (w) = ρair/2 x cb x a x (vw)3 ( 34 ) cb = betz coefficient ( 0.59) ρair = the air density (1.2 kg/m3). a = swept rotor area (m2) vw = wind speed (m/s) the max. tip speed ratio and max. revolution per second are presented as a function of the incoming wind speed in figure ( 7 ). we can see the increase of the tsr when the incoming wind speed increase until the wind speed reaches to 9 m/sec where the increase in tsr become very large ,where reach about (24.22 ) in the wind speed (20 m.sec). conclusions: 1-the choice of tip speed ratio tsr depends on many factors . high tip speed ratio results in higher shaft speed is more efficient for generating electricity which often outweighs the following disadvantages : • noise from the blades is higher ; • starting difficulties if the shaft is stiff to turn. • blades edges at high air -speeds suffer erosion; • reduced rotor efficiently due to drag and tip vortex loss ; 2-from same figures below it is clearly noticed that the increase the incoming wind speed (above 9m/sec.) causes increase of loss of the hub and tip vortex which causes loss in the power output [9], but the program don ’t calculate loss of the hub and tip vortex ,as shown in the figures ( 6 & 7 ) , where we can notice that the productive power larger than the maximum extraction power from betz theorem. 3-the turbine rotor with tip speed ratio 5.901 in a 9 m/s wind speed or a (4 m) diameter rotor running at (5.494 rev/sec) will be at the safer work. but, the working at tip speed ratio above 6m/sec al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 73 the turbine rotor will be at risk from blade erosion. the effect increases dramatically as the speed increases. 4-also, we can specifying the productive power , tip speed ratio and revolution of second of the small wind turbine under the studying as the following ( 2716.122 watt , 5.901 and 5.494 rev/sec). respectively. references: 1) michael s., " wind turbine design optimization" , strategic energy institute, georgia institute of technology, 2007. 2) khan, m. j. , and iqbal, m. t. ," dynamic modeling, simulation and control of a small wind energy conversion system", international conference on mechanical engineering, dhaka, bangladesh, 2003. 3) daniel m. ," wind turbine blade design" , w.t. townshend public school , april 27, 2009. 4) faizul m. k., and quamrul i. , " aerodynamic characteristics of a stationary five bladed vertical axis vane wind turbine" , journal of mechanical engineering, vol. me39, no. 2, december , bangladesh ,2008. 5) young c. k. younguk s., yong w. k. , kyung r. k. , ryu j. y., park j. i., and byun c. j. , " aerodynamic & load calculation for the design of 2 mw wind energy convert system with low speed gearbox ", power center, pohang university of science & technology , pohang, korea; 2007. 6) clifton-smith ,m. j. , and wood ,d. h., " further dual purpose evolutionary optimization of small wind turbine blades ", journal of physics: conference series 75 , australia ,(2007). 7) gary l. j. , " wind turbine power, energy, and torque", http://www.rpc.com.au/products/windturbines/wind-book/wind4., november 21, 2001. 8) henrik stiesdal, "the wind turbine components and operation”, bonus energy a/s fabriksvej 4, box 170 ,1999. 9) david , m. s. "what potential has a micro-wind turbine for rural zambia ?", university of applied sciences school of engineering-mechanical department november ,2002. 10) parent directory ,"area and bending inertia of airfoil sections", http://ocw.mit.edu/nr/rdonlyres/aeronautics-and.../spl10b.pdf . 11) martem ,a. h. j. a., and , albers , p.h.w.m. , " wind turbine study investigation into c vt application in wind turbines", technische universiteit eindhoven,14 october 2003. 12) saeed humaid , and , saleh ali ,"design and manufacturing of a composite wind turbine blade", al fujairah project,2005. http://www.rpc.com.au/products/windturbines/wind-book/wind4 http://ocw.mit.edu/nr/rdonlyres/aeronautics-and.../spl10b.pdf al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 74 table ( 1 ): dimensions of blade under study at each section for naca-4412 airfoil [12]. table ( 2 ): results of the model, (the outputs of the program model). vw(m/s) power(betz) power(watt) no.(rps) tsr startup torque(n.m) max. torque(n.m) 1 1.52e-01 3.725819 1.77e-02 1.71e-01 0.222 1.372396 2 2.856441 29.806552 7.65e-02 3.70e-01 0.889 5.944182 3 22.12679 100.597113 2.13e-01 6.86e-01 2 16.54393 4 174.9202 238.452416 1.09273 2.6407 3.555556 25.47769 5 340.3661 465.727375 1.524284 2.946878 5.555555 35.53966 6 586.8798 804.776904 2.145723 3.456914 8 43.53198 7 929.5349 1277.955917 2.99157 4.131115 10.88889 49.45377 8 1353.417 1907.619328 4.09635 4.949636 14.22222 52.58567 9 1921.592 2716.122051 5.494588 5.901451 18 55.66201 10 2805.88 3725.819 7.220807 6.979943 22.22222 61.84668 11 3979.275 4959.065089 9.309531 8.180903 26.88889 68.03135 12 5500.132 6438.215232 11.79529 9.501527 32 74.21602 13 7432.178 8185.624343 14.71259 10.93987 37.55556 80.40069 14 9844.499 10223.64734 18.09598 12.49454 43.55556 86.58536 15 12811.55 12574.63913 21.97997 14.16452 50 92.77003 16 16413.16 15260.95462 26.39909 15.94906 56.88889 98.95468 17 20734.52 18304.94875 31.38786 17.84756 64.22222 105.1394 18 25866.18 21728.97641 36.98081 19.85958 72 111.324 19 31904.06 25555.39252 43.21245 21.98475 80.22222 117.5087 20 38949.45 29806.552 50.11732 24.22278 88.88889 123.6934 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 75 leading edge f1 chord line plane of rotation trailng edge undisturbed wind relative wind rotational air speed blade motion f2 lift drag figure (1):definitions of pitch angle β ,angle of attack α and all forces and velocities on a translating airfoil. figure(2): quantities for determining and estimating the inertia of an airfoil section [10]. t/c=0.1769 h/c=0.04346 plane of rotation u psteam vw =wind speed downstream blade elements u ndisturbed wind rotation r f1 f2 blade profile of naca 4412 t h c figure ( 3 ):the wind turbine blades with incoming wind speed and effective forces . blade speed= r *ω al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 76 start input data calculate vrev. ,a , im calculate lift , drag , f1 ,f2 calculate torque along each blade total torque ,startup torque , ω calculate calculate power , no. , tsr r = r power ( betz ) calculate vw =20 vw =vw +1 print output data vw, torque, startup torque ,tsr , no. , power ,power(betz ) end figure (4): flow chart of fortran power station program. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 77 figure (5): max. torque load and startup torque at any wind speed. figure (6): max. power produce by torque element compare with betz coefficient theorem at any wind speed. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 78 figure (7): max. tip speed ratio and max. revolution per second at any wind speed. al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 466 effect of binder layer properties on flexible pavement in iraq assist. lecture salam adil mutlag/ misan university email: salampave@yahoo.com abstract premature failure of flexible pavements has a large problem in many iraqi roads with drastic increase in truck axle loads. it is necessary to reduce this early collapse and make the best use of the pavement material in the design of economic. in this paper, the control on the properties of binder layer at the expense of wearing layer to achieve better balance between the damage ratio compared to the most design life are adopted. the methodology is based on the damage analysis concept which is performed for both fatigue cracking and rutting on different pavement sections using kenlayer program. the investigated pavement components are thickness and elasticity modulus for binder layer and thickness of wearing layer. the results of pavement analysis showed that the design life increases with increasing the thickness of wearing layer when the thickness of binder layer increases more than (3.94 in) and it decreases when the thickness of binder layer increase less than (3.94 in). the fatigue damage ratio decreases with increasing the thickness of wearing layer when increasing the thickness of binder layer more than (3.94 in) and it increases with increasing the thickness of wearing layer when increasing the thickness of binder layer less than (3.94 in). the rutting damage ratio increases with increasing the thickness of binder layer and with increasing the thickness of wearing layer. finally, the design life increases with decrease binder moduli and fatigue damage ratio increases with increasing the binder moduli and also the rutting damage ratio decreases with binder moduli (330000 psi). keywords: binder layer, wearing layer, design life, fatigue damage ratio, rutting damage ratio, and kenlayer program. . . binder al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 467 (wearing . kenlayer . binder (wearing. (wearingbinder3.94 (wearingbinder3.94 wearing) ان���ج binder3.94 (wearing binder3.94 binder (wearing 330000 / 1-introduction and background rutting and fatigue cracking are considered the most important distresses surveyed due to high severity and density levels, and consequently their high effects on the pavement condition. flexible pavements should be designed to provide a durable, skid resistance surface under in service conditions. also, it is essential to minimize cracking and rutting in flexible pavement layers. it was necessary to reduce this early collapse and make the best use of the pavement material in the design of economic. the increased rutting or decreased fatigue life of the flexible pavements may be attributed to the shortcomings of the application of flexible pavement analysis and the absence of attention to identify the pavement components that achieve a balanced section which gives equal pavement lives with respect to rutting and fatigue (barksdal, 1978). the variations in the modulus of elasticity of material affect the design life, even though not as significant as the traffic loading (balai nasional.2011). there are various modes in which the pavement fails. cracking of the surface layer and permanent deformation of the pavement system which manifests as rutting on the pavement surface (el-hamrawy, 2000). larger and more concentrated loads produce larger stresses and strains, with thicker layer carrying higher flexural stresses than thinner layers (machemehl, 2005). in pavement analysis, loads on the surface of the pavement produce two strains which are believed to be critical for design purposes. these are the horizontal tensile strain; εt at the bottom of the asphalt layer and the vertical compressive strain; εc at the top of the subgrade layer. if the horizontal tensile strain; εt is excessive, cracking of the surface layer will occur, and the pavement distresses due to fatigue. if the vertical compressive strain; εc is excessive, permanent deformation occurs at the surface of the pavement structure from overloading the subgrade, and the pavement distresses due to rutting ((mulungye, 2006), (dessouky, 2007) and ((ms-1), 1982)) 468 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 the main objective of this study is to investigate the effects of binder layer components, thickness and elasticity modulus on pavement life with respect to fatigue and rutting. 2-pavement response analysis methodology the kenlayer computer program (huang, 2004) was used to calculate the tensile strain (εt) at the bottom of the asphalt layer and the compressive strain (εc) at the top of the sub-grade soil. these computed strains are incorporated in the fatigue cracking and rutting models to estimate the pavement life. 2-1 fatigue criteria the relationship between fatigue failure of asphalt concrete and tensile strain (εt) at the bottom of asphalt layer is represented by the number of repetitions as suggested by asphalt institute ((ms-1), 1982) in the following form equation (1): nf = 0.0796 (1/εt) 3.291 (1/e1) 0.854 (1) where: nf: number of load repetitions to prevent fatigue cracking. εt: tensile strain at the bottom of asphalt layer. e1: elastic modulus of asphalt layer. 2-2 rutting criteria the relationship between rutting failure and compressive strain (εc) at the top of subgrade is represented by the number of load applications as suggested by asphalt institute ((ms-1), 1982) in the following form equation (2): nr = 1.365 * 10-9 (1/ εc) 4.477 (2) where: nr: number of load applications to limit rutting. εc: vertical compressive strain, at the top of sub-grade 2-3-investigated pavement cross sections a typical cross section consists of wearing layer thickness (1.58-in) with elasticity modulus (380,000 psi), binder layer thickness (3.15-in) with elasticity modulus (330,000 psi), base layer thickness (7.09-in) with elasticity modulus (230,000 psi), and sub base layer thickness (15.75-in) with elasticity modulus (16,000 psi), resting on sub grade with elasticity modulus (7,000 psi) is considered a section with reference components. different probable cross sections that may be used in iraqi roads for binder layer are considered for analysis through varying the reference components by ± 25 % and ± 50 % are (1.58, 2.36, 3.15, 3.94, and 4.72) in. four values of thickness are considered plus the reference one , ± 25 % are (247500,330000,412500) psi two values of elasticity modulus are considered plus the reference one and ± 25 % are (0.79, 1.18, 1.58)in two values of thickness of wearing layer are considered plus the reference one. varying these components with each other give various cross sections for analysis. 2-4 pavement analysis al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 469 flexible pavement is typically taken as a multi-layered elastic system in the analysis of pavement response. materials in each layer are characterized by a modulus of elasticity (e) and a poisson’s ratio (μ). poisson’s ratio; μ is considered as 0.3, 0.35, 0.40, 0.40 and 0.45 for wearing layer, binder layer ,base course, sub-base layer and sub-grade, respectively. traffic is expressed in terms of repetitions of single axle load 18-kip applied to the pavement on two sets of dual tires. the investigated contact pressure is 140 psi. the dual tire is approximated by two circular plates with radius 3.86-in. and spaced at 13.60-in. center to center. 2-5 damage prediction the prediction of pavement life is based on the cumulative damage concept in which a damage factor is defined as the damage per pass caused to a specific pavement system by the load in question. the damage (di) caused by each application of a single axle load at any season can be given by equation (3): where ni is the minimum number of load repetitions required to cause either fatigue or rutting failure, as given by equations (1) and (2). the total number of load repetitions (nf) that are allowed over the pavement lifetime can be determined when total cumulative damage (dt) reaches one. therefore, equations (1) and (2) can then be solved for the total allowable number of load applications required to cause either fatigue or rutting failures over the pavement lifetime. the design life is computed through equation 4 and calculated for fatigue cracking and for permanent deformation, and the one with a shorter life controls the design in period i. 3analysis of results multilayer elastic analysis is performed using the kenlayer software. the different variables discussed in the previous section are considered. the resulting pavement strains, damage and design life showed below sections. 3-1 effect of thickness layer on pavement strains and damage ratios figures 1, 2 and 3 show the relationship between tensile strain at the bottom of the binder layer versus thickness for different binder moduli and thickness` of wearing. the figures show that the tensile strain first decrease with increasing thickness of binder then with (3.94 in) increasing thickness. notes that with increase thickness of wearing layer increase tensile strain and increase modulus of binder layer increase tensile strain. on the other hand, figures 4, 5 and 6 show the relationship between the compressive strain at the top of subgrade soil versus thickness for different binder moduli. the compressive strain increases in a linear function with increasing the thickness of binder layer. it also shows that the rate of increase (slope of the line) is greater with binder layer having modulus (330000 psi) (3) (4) 470 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 3-2 effect of thickness of binder on damage ratios the estimated fatigue and rutting damage ratios versus thickness are presented in figures 7, 8 and 9 for different binder layer moduli and thickness of wearing layer . the figures show that the fatigue damage with first increases in a linear function with increasing the thickness for greater binder moduli then decrease for thickness (3.94 in). notes that with increase thickness of wearing layer increase fatigue damage and increase modulus of binder layer increase fatigue damage. figures 10, 11 and 12) show that the rutting damage increases in a linear function with increasing the thickness for greater binder moduli. notes that with increase thickness of wearing layer increase fatigue damage and it also shows that the rate of increase (slope of the line) is greater with binder layer having modulus (330000 psi). 3-3 effect of axle load on the pavement design life the pavement design life is the minimum number of load repetitions required to cause either fatigue or rutting failure, as given by equations 1 and 2. figures 13, 14 and 15 show that the design life with first decreases in a linear function with increasing the thickness then increase with increasing the thickness, while increases with decrease binder moduli. 4conclusions based on this study the following can be concluded: 1the design life increases with increasing the thickness of wearing layer when increasing the thickness of binder layer more than (3.94 in). 2design life decreases with increasing the thickness of wearing layer when increasing the thickness of binder layer less than (3.94 in). 3design life increases with decrease binder moduli. 4the fatigue damage ratio decreases with increasing the thickness of wearing layer when increasing the thickness of binder layer more than (3.94 in). 5fatigue damage ratio increases with increasing the thickness of wearing layer when increasing the thickness of binder layer less than (3.94 in). 6rutting damage ratio increases with increasing the thickness of binder layer and with increasing the thickness of wearing layer. 7fatigue damage ratio increases with increasing binder moduli while the rutting damage ratio decreases with binder moduli (330000 psi). 6-references asphalt institute, “research and development of the asphalt institute’s thickness design manual", 9th edition, research report 82-2, the asphalt institute, (ms-1) 1982. barksdal, r. d., “practical application of fatigue and rutting tests on bituminous base mixes”, proceedings, aapt, vol. 47, 1978. dessouky, s. h., al-qadi, i. l., and yoo, p. j., “full-depth flexible pavement response to different truck tire loadings”, transportation research board, 86th annual meeting, jan., 2007. al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 471 balai nasional, ditjen marga, kementerian umum “sensitivity analysis in flexible pavement performance using mechanistic empirical method” jl. pattimura no.20, kebayoran baru jakarta selatan,2011 el-hamrawy, s., “effect of wheel load, tire pressure and subgrade stiffness on flexible pavements responses)”, al-azhar engineering 6th international conference, sept. 2000. huang, yang h., "pavement analysis and design," englewood cliffs, new jersey, 2004. machemehl, r. b., wang, f., and prozzi, j. a., “analytical study of effects of truck tire pressure on pavements with measured tirepavement contact stress data”, transportation research board 2005. mulungye, r.m., owende, p.m.o., and mellon, k., “determining the effect of tyre pressure, axle load and wheel configuration on flexible pavements fatigue life using finite element method” proceeding 522, applied simulation and modelling, 2006. table 1 the structural properties of the investigated pavement cross sections. effect of thickness of binder on tensile strain wearing layer =1.58 in 1 1.5 2 2.5 3 3.5 4 4.5 5 -1.00e-04-9.00e-05-8.00e-05-7.00e-05-6.00e-05-5.00e-05-4.00e-05 tensile strain th ic k n e s s e=247500 e=330000 e=412500 figure 1 effect of thickness of binder on tensile strain wearing layer =1.58 in 472 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 effect of thickness of binder on tensile strain wearing layer =1.18 in 1 1.5 2 2.5 3 3.5 4 4.5 5 -1.00e-04-9.00e-05-8.00e-05-7.00e-05-6.00e-05-5.00e-05-4.00e-05 tensile strain th ic k n e s s e=247500 e=330000 e=412500 figure 2 effect of thickness of binder on tensile strain wearing layer =1.18 in effect of thickness of binder on tensile strain wearing layer =0.79 in 1 1.5 2 2.5 3 3.5 4 4.5 5 -1.00e-04-9.00e-05-8.00e-05-7.00e-05-6.00e-05-5.00e-05-4.00e-05 te nsile strain th ic k n e s s e=247500 e=330000 e=412500 figure 3 effect of thickness of binder on tensile strain wearing layer =0.79 in effect of thickne ss of binder on compressiv e strain we aring laye r =1.58 in 1 1.5 2 2.5 3 3.5 4 4.5 5 4.00e-05 6.00e-05 8.00e-05 1.00e-04 1.20e-04 1.40e-04 1.60e-04 compre ssive strain th ic k n e s s e=247500 e=330000 e=412500 figure 4 effect of thickness of binder on compressive strain wearing layer =1.58 in al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 473 effect of thickness of binder on compressive strain wearing layer =1.18 in 1 1.5 2 2.5 3 3.5 4 4.5 5 4.00e-05 6.00e-05 8.00e-05 1.00e-04 1.20e-04 1.40e-04 1.60e-04 compressive strain th ic k n e s s e=247500 e=330000 e=412500 figure 5 effect of thickness of binder on compressive strain wearing layer =1.18 in effect of thickness of binder on compressive strain wearing layer =0.79 in 1 1.5 2 2.5 3 3.5 4 4.5 5 4.00e-05 6.00e-05 8.00e-05 1.00e-04 1.20e-04 1.40e-04 1.60e-04 compressive strain th ic k n e s s e=247500 e=330000 e=412500 figure 6 effect of thickness of binder on compressive strain wearing layer =0.79 in effect of thickness of binder on fatigue damage ratio wearing layer =1.58 in 1 1.5 2 2.5 3 3.5 4 4.5 5 0.00e+00 5.00e-03 1.00e-02 1.50e-02 2.00e-02 2.50e-02 fatigue damage ratio th ic k n e s s e=247500 e=330000 e=412500 figure 7 effect of thickness of binder on fatigue damage ratio wearing layer =1.58 in 474 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 effect of thickness of binder on fatigue damage ratio wearing layer =1.18 in 1 1.5 2 2.5 3 3.5 4 4.5 5 0.00e+00 5.00e-03 1.00e-02 1.50e-02 2.00e-02 2.50e-02 fatigue damage ratio th ic k n e s s e=247500 e=330000 e=412500 figure 8 effect of thickness of binder on fatigue damage ratio wearing layer =1.18 in effect of thickness of binder on fatigue damage ratio wearing layer =0.79 in 1 1.5 2 2.5 3 3.5 4 4.5 5 0.00e+00 5.00e-03 1.00e-02 1.50e-02 2.00e-02 2.50e-02 fatigue damage ratio th ic k n e s s e=247500 e=330000 e=412500 figure 9 effect of thickness of binder on fatigue damage ratio wearing layer =0.79 in effect of thickness of binder on rutting damage ratio wearing layer =1.58 in 1 1.5 2 2.5 3 3.5 4 4.5 5 0.00e+00 3.00e-04 6.00e-04 9.00e-04 1.20e-03 1.50e-03 1.80e-03 2.10e-03 rutting damage ratio th ic k n e s s e=247500 e=330000 e=412500 figure 10 effect of thickness of binder on rutting damage ratio wearing layer =1.58 in al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 475 effect of thickness of binder on rutting damage ratio wearing layer =1.18 in 1 1.5 2 2.5 3 3.5 4 4.5 5 0.00e+00 3.00e-04 6.00e-04 9.00e-04 1.20e-03 1.50e-03 1.80e-03 2.10e-03 rutting damage ratio th ic k n e s s e=247500 e=330000 e=412500 figure 11 effect of thickness of binder on rutting damage ratio wearing layer =1.18 in effect of thickness of binder on rutting damage ratio wearing layer =0.79 in 1 1.5 2 2.5 3 3.5 4 4.5 5 0.00e+00 3.00e-04 6.00e-04 9.00e-04 1.20e-03 1.50e-03 1.80e-03 2.10e-03 rutting damage ratio th ic k n e s s e=247500 e=330000 e=412500 figure 12 effect of thickness of binder on rutting damage ratio wearing layer =0.79 in effect of thickness of binder on design life wearing layer =1.58 in 1 1.5 2 2.5 3 3.5 4 4.5 5 6.0 11.0 16.0 21.0 26.0 years th ic k n e s s e=247500 e=330000 e=412500 figure 13 effect of thickness of binder on design life wearing layer =1.58 in 476 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 466-476, year 2012 effect of thickness of binder on design life wearing layer =1.18 in 1 1.5 2 2.5 3 3.5 4 4.5 5 6.0 11.0 16.0 21.0 26.0 years th ic k n e s s e=247500 e=330000 e=412500 figure 14 effect of thickness of binder on design life wearing layer =1.18 in effect of thickness of binder on design life wearing layer =0.79 in 1 1.5 2 2.5 3 3.5 4 4.5 5 6.0 11.0 16.0 21.0 26.0 years th ic k n e s s e=247500 e=330000 e=412500 figuer 15 effect of thickness of binder on design life wearing layer =0.79 in 8-2-2011.pdf 93 a novel design for compact microstrip bandpass filter design is presented for use in the application of modern wireless communication systems. the proposed filter structure is composed of two fractal-based microstrip resonators. the structure of each resonator is in the form of the peano fractal curve geometry. two microstrip single-mode resonators with structures based on the 2nd peano fractal-shaped geometries have been modeled at a design frequency of 2.4 ghz. the resulting filter structures based on these resonators, show considerable size reduction compared with the other microstrip bandpass filters based on other space-filling geometries designed at the same frequency. the performance of the resulting filter structures has been evaluated using a method of moments (mom) based software package, microwave office 2009, from advanced wave research inc. results show that the proposed filter structures possess good return loss and transmission responses besides the size reduction gained, making them suitable for use in a wide variety of wireless communication applications. furthermore, performance responses show that the new resonator has less tendency to support the higher harmonics. / / : . . . . )٢٠٠٧mwo()awr( . 94 . fractal geometry has been used in almost all the fields of science and art, since the pioneer work of mandelbrot about three decades ago [mandelbrot, 1983]. among these fields are the physical and engineering applications. in electromagnetics, fractal geometries have been applied widely in the fields of antenna and passive microwave circuit design, due the fantastic results gained in the miniaturization and the performance as well. in modern wireless and mobile communication systems, filters are always playing important and essential roles. planar filters are particularly popular structures because they can be fabricated using printed circuit technology and they are suitable for commercial applications due to their compact size and low-cost integration . dramatic developments in wireless communication systems have imposed new challenges to design and produce high selectivity miniaturized components. these challenges stimulate microwave circuits and antennas designers to seek out for solutions by investigating different fractal geometries [chen, 2007, xiao, , 2007, wu, , 2008]. different from euclidean geometries, fractal geometries have two common properties, space-filling and self-similarity. it has been shown that the space-filling property of fractals can be utilized to reduce filter size. research results showed that, due to the increase of the overall length of the microstrip line on a given substrate area as well as to the specific line geometry, using fractal curves reduces resonant frequency of microstrip resonators, and gives narrow resonant peaks[crnojevic, 2006, kim, 2006, xiao, , 2007, wu, , 2008]. hilbert fractal curve has been used as a defected ground structure in the design of a microstrip lowpass filter operating at the l-band microwave frequency [chen, , 2007]. sierpinski fractal geometry has been used in the implementation of a complementary split ring resonator [crnojevicbengin, 2006]. split ring geometry using square sierpinski fractal curves has been proposed to reduce resonant frequency of the structure and achieve improved frequency selectivity in the resonator performance. koch fractal shape is applied to mm-wave microstrip bandpass filters integrated on a high-resistivity substrate. results showed that the 2nd harmonic of fractal shape filters can be suppressed as the fractal iteration level increases, while maintaining the physical size of the resulting filter design [kim, , 2006]. minkowski-like and koch pre-fractal geometries have been successfully used in producing high performance miniaturized dual-mode microstrip bandpass filters [ali, 2008, ali, , 2009]. in this paper, new microstrip bandpass filters, based on peano fractal geometry, have been presented as a candidate for use in compact communication systems. the proposed single-mode bandpass filters have been found to possess compact sizes with accepted return loss and transmission responses. the hilbert fractal curve, as outlined in , consists in a continuous line which connects the centers of a uniform background grid. the fractal curve is fit in a square section of as external side. by increasing the iteration level of the curve, one reduces the elemental grid size as 13 ; the space between lines diminishes in the same proportion. for a peano resonator, made of a thin conducting strip in the form of the hilbert curve with side dimension and order , the length of each line segment and the sum of all the line segments ( ) are given by [ ali and mezaal, 2009] : 13 (1) the main idea here is to increase the iteration of the peano curve as much as possible in order to fit the resonator in the smallest area. however, it has been found that, when dealing with space-filling 95 fractal shaped microstrip resonators, there is a tradeoff between miniaturization (curves with high ) and quality factor of the resonator. for a microstrip resonator, the width of the strip and the spacing between the strips are the parameters which actually define this tradeoff [ ali and mezaal, 2009, barra, 2004]. both dimensions ( and ) are connected with the external side and iteration level ( ≥2) by 3 (2) from this equation, it is clear that trying to obtain higher levels of fractal iterations; this will lead to lower values of the microstrip width, thus increasing the dissipative losses with a corresponding degradation of the resonator quality factor. hence, for these structures, the compromise between miniaturization and quality factor is simply defined by an adequate fractal iteration level. however, it has been concluded, in practice, that the number of generating iterations required to reap the benefits of miniaturization is only few before the additional complexities become indistinguishable [gianvittorio, 2003]. at first, a single resonator based on the 2nd iteration peano fractal geometry, has been designed at a frequency of 2.4 ghz. it has been supposed that the modeled filter structures have been etched using a substrate with a relative dielectric constant of 10.8 and a substrate thickness of 1.27 mm. the resulting resonator dimensions have been found to be 4.27 mm × 4.27 mm, and a trace width of about 0.365 mm. the guided wavelength λg at the design frequency and the stated substrate parameters is calculated by [hong , , 2001, chang, 2004]: (3) where 21 . the same resonator with depicted dimensions and substrate specifications has been used to build a two-resonator microstrip bandpass filter. the input/output feed tab positions and spacing between the resonators are the most important parameters affecting the filter performance [hong, , 2001, swanson, 2007]. the topology of this filter is shown in . the overall dimensions of this filter are of about 4.75 mm × 8.7 mm. the corresponding return loss and transmission responses are shown in . it is clear, from that the resulting bandpass filters based on the 2nd iterations peano fractal geometries offer good quasi-elliptic transmission responses with transmission zeros that are symmetrically located around the design frequency with return losses are of about 11 and insertion losses of about 0.4. shows the out-of-band transmission responses of the two filters for 2nd iteration resonator filters. it is clear that performance response has fewer tendencies to support higher harmonics which conventionally accompany the bandpass filter performance. the proposed filter designs can be applied to many other wireless communication systems; the filter dimensions can easily be scaled up or down depending on the required operating frequencies. shows the linear phase response for s11 and s12 with respect to different frequencies. and demonstrate the surface current distribution on the conducting surface of both resonators at 2.4 ghz and 2.5 ghz frequencies, where red color indicates higher coupling effect while blue color indicates the opposite effect. it is clear from these figures that the nature of current distribution changes with the variation of operating frequency. it is necessary to mention that the proposed design of quasi elliptic response 2nd iteration peano bandpass filter in this paper suppresses higher harmonics without additional stubs with relative dielectric constant of 10.8 and dielectric thickness of 1.27 as compared with [ali and mezaal, mape 2009] that suppresses only the 2nd harmonic by using chebychev response 3rd iteration 96 peano bandpass filter which uses dielectric constant of 9.8 and dielectric thickness of 0.508 with additional stubs. a new quasi elliptic response two-pole microstrip bandpass filter design for use in modern wireless communication systems has been introduced in this paper. the proposed filter structures have been composed of dual coupled resonators which are based on 2nd iteration peano fractal curves. the space-filling property the proposed filter structure possesses, results in a high degree of miniaturization with reasonable passband performance. consequently, the proposed technique can be generalized as a flexible design tool for compact microstrip bandpass filters for a wide variety of wireless communication systems. also, it has been found that performance responses show that the new filter has less tendency to support successive harmonic. ali, j.k., (2008). “a new miniaturized fractal bandpass filter based on dual-mode microstrip square ring resonator,” proceedings of the 5th international multi-conference on signals, systems and devices amman, jordan, july 20-23. ali, j.k., (2009). a new fractal microstrip bandpass filter design based on dual-mode square ring resonator for wireless communication systems, , , vol.5, no.1, pp:7-12. ali, j.k and mezaal, y.s.,(2009), “a new miniature narrowband bandpass filter design for wireless communication based on peano fractal geometry”, iraqi journal of applied physics, vol.5, no.4, pp:3-9. ali, j.k and mezaal, y.s.,(2009), “a new miniature peano fractal-based bandpass filter design with 2nd harmonic suppression” accepted for publication at 3rd ieee international symposium on microwave, antenna, propagation, and emc technologies for wireless communications (mape 2009) , 27-29, beijing, china. barra, m., c. collado, j. mateu, and j. m. o’callaghan, (2004). “hilbert fractal curves for hts miniaturized filters,” microwave symp. dig., ieee-mtt-s int., pp:123-126. chang k., and l.h. hsieh, (2004). second edition, john wiley and sons ltd., new jersey. chen, j., z.b. weng, y.c. jiao and f. s. zhang, (2007). “lowpass filter design of hilbert curve ring defected ground structure,” , vol. 70, pp:269-280. crnojevic-bengin, v., v. radonic, and b. jokanovic, (2006). “complementary split ring resonators using square sierpinski fractal curves,” , manchester, uk, pp:1333-1335. gianvittorio, j.p., (2003). “fractals, mems, and fss electromagnetic devices: miniaturization and multiple resonances,” phd thesis, university of california, u.s.a . hong, j.s., and m.j. lancaster, (2001). john wiley and sons inc., new york. kim, i.k., n. kingsley, m.a. morton, s. pinel, j. papapolymerou, m.m. tentzeris, j. laskar and j.g. yook, (2006). “koch fractal shape microstrip bandpass filters on high resistivity silicon for 97 the suppression of the 2nd harmonic,” vol.6, no.4, pp:1-10. mandelbrot, b.b., (1983). “ w. h. freeman and company new york. microwave office and emsight, (2009). “user’s manual”, applied wave research, usa, el segundo, ca. swanson, d. g., (2007). “narrow-band microwave filter design,” ieee microwave mag., vol.8 no.5, pp: 105-114. wu, g.l., w. mu, x.w. dai, and y.c. jiao, (2008). “design of novel dual-band bandpass filter with microstrip meander-loop resonator and csrr dgs,” , vol. 78, pp:17-24. xiao, j.k., q.x. chu and s. zhang, (2007). “novel microstrip triangular resonator bandpass filter with transmission zeros and wide bands using fractal-shaped defection,” , vol. 77 pp:343-356. the first three iteration levels of the peano fractal curve generation process 98 the modeled microstrip bandpass filter with two resonators based on 2nd iteration peano curve geometry the return loss and transmission responses of the resulting 2nd iteration fractal tworesonator microstrip bandpass filter 99 the out-of-band transmission responses of the proposed filters based on the 2nd iteration peano curve geometry. the phase responses of the resulting 2nd iteration fractal two-resonator microstrip bandpass filter 100 current density distribution at the conducting surface of the 2nd iteration stubbed peano bandpass filter simulated at a resonant frequency of 2.4 ghz current density distribution at the conducting surface of the 2nd iteration stubbed peano bandpass filter simulated at a resonant frequency of 2.5 ghz al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٢ shear effect on the elastic-plastic large displacement stability analysis of plane steel frames with members resting on elastic foundation abstract: in this paper, a theoretical analysis is presented for estimating the in-plane large displacement elastic-plastic behavior of steel frames having members resting on elastic foundation subjected to either proportional or nonproportional increasing static loads and including shear deformation effect. the analysis adopts the beamcolumn approach and models the structure’s members as beam-column elements. the formulation of the beamcolumn element is based on eulerian approach allowing for the influence of the axial force on bending stiffness. also, changing in member chord length due to axial deformation, flexural bowing and shear deformation effect are taken into account. the formation of tangent stiffness matrix for the member in local and global coordinates with geometric and material nonlinearly including shear effect have been presented. in a special procedure, the calculation of axial force and plastic moment capacity including shear effect has been explained. new interaction equations between the axial force, shear force and plastic moment capacity for box and i-steel sections are presented in this study. the present search has adopted the linear and nonlinear behaviors of soil and these behaviors have been presented by isolated springs at the nodes. the computational technique utilizes an incremental load approach with a newton-raphson iteration to satisfy joint equilibrium equations. in order to verify the efficiency of the present formulation, some case studies reported by previous researches are utilized. the investigation is extended to study the effect of shear deformation on the elastic plastic behavior of structures resting on elastic foundation. as a result of this investigation, several important conclusions are obtained, which assure the necessity of taking into account the shear effect in the analysis of large displacement elastic-plastic behavior of structures resting on elastic foundation. keywords: shear effect, stability, large displacement, elastic-plastic, shear interaction, soil effect. dr. hayder t. nimnim (asst. professor) college of engineering / kufa university e-mail: haydernimnim@yahoo.com waseem h. mahdi (asst. lecturer) college of engineering / kufa university e-mail: ws_forever2009@yahoo.com al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٣ أللدنة للھياكل ألحديدية ألمستوية تأثير القص في تحليل ا�زاحات الكبيرة و ا�ستقرارية ألمرنة و ألمرتبطة بأعضاء مسندة على أساس مرن حيدر طالب نمنم وسام حمزة مھدي.د كلية الھندسة –جامعة الكوفة :ألخالصة اللدنـة للهياكـل الحديديـة المسـتوية والتـي تحتـوي علـى أعضـاء مسـتندة علـى -ةيتناول البحث دراسة التحليل النظري للسلوكية المرن . أساس مرن ومعرضة ألحمال ساكنة متناسبة وغير متناسبة مع األخذ بنظر االعتبار اإلزاحات الكبيرة الحاصـلة فيهـا وتـأثير القـص مـــع األخــذ بنظـــر م باالعتمـــاد علــى طريقـــة اويلــرإن اشـــتقاق عنصــر العمـــود العتبــة قـــد تــ. تبنــت هــذه الدراســـة طريقــة العمـــود العتبــة كذلك اخذ بنظر االعتبار تأثير التغيرات في طول الوتر نتيجة االنفعـال المحـوري ، االعتبار تأثير القوة المحورية على صالبة العزم والعــام مــع ألمــوقعييات بينــت الدراســة اشــتقاق مصــفوفة الصــالبة المماســية فــي نظــام اإلحــداث. وتقــوس االنحنــاء وتــأثير تشــوه القــص األخذ بنظر االعتبار تغير الشـكل وتصـرف المـادة الالخطـي وتـأثير القـص باإلضـافة إلـى ذلـك تـم بيـان طريقـة خاصـة لحسـاب القـوة تـم. تم استعمال عالقة لبيان التأثير المشترك بين القوة المحورية وسعة العزم اللدن مع األخذ بنظـر االعتبـار تـأثير القـص. المحورية اشتقاق معادلة جديدة لبيان التأثير المشترك بين القوة المحورية وقوة القص وسعة العزم اللدن للمقاطع الحديدية الصـندوقية والمقـاطع لقــد تــم .رالعنصــف قــد مثــل بنــوابض فــي نهايــات الالخطــي للتربــة وهــذا التصــر تبنــت الدراســة التصــرف الخطــي وi). (مــن نــوع -وقــد اســتخدمت طريقــة الحمــل المتزايــد مــع تكــرار نيــوتن. لمســتخدم لتتبــع المنحنــي الالخطــي للمنشــاتألســلوب الحســابي اتوضــيح أ تــم مقارنــة نتــائج التحليــل مــع نتــائج ،المقدمــةولغــرض تقيــيم فعاليــة الدراســة . رافســون لتحقيــق معــادالت التــوازن فــي نهايــات العنصــر اللدنــة للمنشــات الحاويــة علــى -ثير دراســة القــص علــى الســلوكية المرنــةتــم توســيع هــذه الدراســة لتتنــاول تــأ. دراســات منشــورة ســابقا كد ضرورة إدخال تأثير القص في التحليل المرن ؤ نتيجة لهذه الدراسة تم التوصل إلى عدة نتائج مهمة ت. أعضاء مستقرة على التربة .اللدن للمنشات المستقرة على التربة – introduction: in recent years, global attention and interest has grown in the nonlinear behavior of framed structures. the nonlinearity response of structures having members resting on elastic foundation such as (railway tracks, continuously supported pipe lines, piles and strip foundation) results from many effects some of these are the effect of large displacements and large strains (geometrical nonlinearity), material nonlinearity and the effect of shear deformation. in structures with some of their members supported or driven into soil, the structural behavior of frameworks will be influenced significantly by the restrained caused by the foundation, and the amount of influence will be dependent on the flexural rigidity of the embedded members and the soil modulus (bowels ١٩٩٦). also, in these structures shear effect is important especially on the deflection, and its effect submit to many factors such as; span to depth ratio, the cross-section of the member, and soil modulus (aydogan ١٩٩٥ ) . substantial amount of literature on the nonlinear behavior of structures with members resting on soil with shear deformation effect has been undertaken in recent years. al-sarraf 1986 studied the shear effect on the elastic stability of frames. modified stability functions for prismatic beam-columns having any solid cross-sectional shapes, laced or battened built-up sections were developed. eisenberger and yankelevsky 1987 presented an iterative procedure for the analysis of beams resting on nonlinear elastic foundation based on the exact solution for beams on a linear al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٤ elastic foundation. the nonlinear characteristics of the foundation are approximated by the piecewise linear curve. al-hachami 1997, presented large displacement elastic stability analysis of a beam-column resting or driven into elastic foundation. he adopted two approaches to representing the reaction of soil. the first approach represents the soil as isolated spring at nodes of abeam-column element and the second one, the elastic foundation is considered as uniformly distributed winkler-type spring support. onu 2000 produced a formulation leading to an explicit free-of-meshing stiffness matrix for the beam finite element on two parameter elastic foundation. considering the shear deformation contribution, the formulation based on the exact solution of the governing differential equation. jawad 2002, presented a theoretical analysis for estimating the in-plane large displacement elasticplastic behavior of steel frames having prismatic members and resting on soil. approximate expression presented to describe the interaction curves between the axial force and plastic moment capacity of wide rang of steel sections. the analysis has adopted the linear and nonlinear behaviors of soil and these behaviors have represented by isolated springs at nodes. in the present study, a theoretical bases of the large displacement elastic-plastic analysis of plane steel structures having members resting on elastic foundation using a beam-column approach and including shear effect is presented. the formulation of the beam column element is based on eulerian approach allowing the influence of the axial force on bending stiffness. also changes in member chord length due to axial deformation and flexural bowing are taken into account. the formation of tangent stiffness matrix for the member in local and global coordinates with geometric and material nonlinearly has been presented. in a special procedure, the calculation of axial force has been explained. in order to verify the effect of shear in plastic moment capacity, new interaction equation between the axial force, shear force and plastic moment capacity of a box and i-steel sections is presented in this study. for soil representation, linear and nonlinear isolated spring behaviors are utilized and these behaviors have been represented by isolated springs at nodes. the algorithm of computer program (nepapfss) is developed in this research. in order to display the effectiveness of this computer program, some examples reported by previous researches are utilized. as it is obvious from the literature review, there is no one using the beam-column approach (as far as author knowledge) to study the effect of shear on the elastic-plastic large displacements stability analysis of steel frames having members resting on elastic foundation. shear deformation: the basic theory of shear effect for a prismatic member and the methods that deals with shear deformation and the derivation of shear flexibility parameter for a solid member will be presented. in addition, the stability and bowing functions including shear effect will be presented. methods of including shear deformation: the effect of shear on curvature of element and consequently on the stability and bowing functions have a variable influence depending on type of member. this effect is analyzing by using two approaches as follows (sideek 2005): 1the first approach (total slope approach) this approach is based on the assumption that the shear component of axial force is calculated from the total slope (bending and shear slope). 2the second approach (bending slope approach) this approach is based on the assumption that the shear component of axial force is calculated from the bending slope. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٥ shear flexibility parameter for prismatic member: the shear effect on the elastic stability analysis depends on the type of structure, whether it is open or closed web structure. the open web structure exhibits relatively higher shear deformation than the solid one therefore it must be introduce a parameter which gives us a sense about how much the effect of shear will be on that structure. the derivation of shear flexibility parameter produced by timoshenko and gere 1961are presented as follows: an element of length "l" of a structural member is considered as shown in fig.(1). this member is acted upon by axial force "q", shearing force "v", and bending moment "m". the deformation is separated into two parts; (1) bending and (2) shear. bending produces a change in slope in length "l" of ; ei ml l=φ (1) in addition, shear produces a change in slope of ; gav vn γ= (2) where, ei : flexural rigidity of the member. ga : shear rigidity of the member, and n : shear shape factor. av : effective shear cross-sectional area. thus, within the length (l), the ratio of change in slope caused by shear to that caused by moment is defined as “shear flexibility parameter (µ)” and it is equal to gav qn µ= e (3) where ; qe : euler load. typical values of the shear shape factor for solid member are giving as follows timoshenko and gere 1961. type of section shear shape factor (n) rectangular cross-section 1.20 circular cross-section 1.11 i – section bent about minor axis 1.2a / af = (1.4 2.8) i – section bent about major axis a / aw = (2 6) where :af = area of two-flanges , aw = area of the web, a = total cross-sectional area elastic large displacement analysis with shear effect: the following method of analysis is an extension of the elastic large displacement formulation presented in (oran, and kassimali 1976). the ideas previously reported are reviewed in the present study. the relationship between relative member deformations, θ1,θ2 and u and associated member end forces m1,m2 and q of the elastic prismatic member shown in fig.(2),can be based on beam column theory as follows: al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٦ m1= ei /l (c1 θ1+c2 θ2) (4) m2=ei /l (c2θ1+c1θ2) (5) q =ea /l (u –cb. l) (6) in which c1 and c2 : conventional elastic stability functions, where, c1: flexural stiffness factor. c2: flexural moment carry over-factor. e: modulus of elasticity, i: moment of inertia, a: cross-sectional areal, l: initial member length. u: axial displacement, and; cb= b1 (θ1+θ2) 2 + b2 (θ1-θ2) 2 (7) is the length correction factor due to bowing action, with b1,b2 are bowing functions. in the present study stability functions (c1, c2) and bowing functions (b1, b2) is replaced with modified functions including shear effect .thus, equations (4) to (7) become: m1= ei /l (c1 θ1+c2 θ2) (8) m2=ei /l (c2θ1+c1θ2) (9) q =ea /l (u –cb. l) (10) cb= b1 (θ1+θ2) 2 + b2 (θ1-θ2) 2 (11) where c1, c2, b1, b2 are the modified stability and bowing functions including shear effect. explicit expressions for stability and bowing functions including shear effect in terms of axial force parameter (q) and shear flexibility parameter are summarized in appendix a. eiπ ql = qeuler q q= 2 2 (12) the incremental relationship between the member end forces and end displacements in global coordinates can be written as: {∆f}= [t] {∆v} (13) in which the [t] = the member tangent stiffness matrix in global coordinates and given by ∑ 3 1k= g k s+btb=t (k)t                         (14) in which sk : the local forces which represents (m1) and (m2) and (ql) for k=1,2 and 3 respectively as shown in fig.(٢). [g(k)] : geometric matrices which have the expression given in the appendix a for k=1,2 and 3 [b] : the transformation matrix, which has the expression given in appendix a. [t] : the member tangent stiffness matrix in local (eulerian) coordinates which defined by al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٧                                   − −−     + ++ = h sym h g h g c h g h gg c h g c l ei t 2 2 2 2 2 1 1 2 21 22 1 1 2 π π ππ (15) in which ( ) ( )[ ] 221121 2 22111 θb′b′+θb′+b′π2=θ ′ c+θ ′ c=g (16) ( ) ( )[ ] 221121 2 21121 θb′+b′+θb′b′π2=θ ′ c+θ ′ c=g (17) and 2 212 2 211 )θ(θb+)+θ(θb+ 2λ 2π h= −′′ (18) in which i/a l λ= (19) in addition, a prime superscript on ci or bi denotes a differentiation with respect to q. the stability and bowing functions, the geometric matrices and the transformation matrix are given in appendix a. elasticplastic analysis with shear effect: an important step in the design of steel frame structures is the calculation of their ultimate load currying capacity. the accuracy of such calculation depends largely on numerical models used in the analysis procedure. as far as the effect of plasticity is concerned, a convenient concept in modeling the collapse mechanism of steel frames has been the introduction of zero length plastic hinges at a member ends (oran, and kassimali 1976). when steel frame undergoes a large plastic deformation, plastic hinges are expected to form at any section when moment of a member becomes equal to the plastic moment capacity of the member and the slope continuity at the end of the element, where the plastic hinge is located, will be destroyed. in other words, the particular end of the element can rotate independently of the joint and an additional degree of freedom is created. the material is assumed to be ideally elastic-plastic, and yielding is considered to be concentrated at member ends in the form of plastic hinges. a plastic hinge will form when the moment equals to the reduced plastic moment capacity (mpc) of the member . the member is assumed to remain elastic between plastic hinges. the reversals of plastic hinge rotations are not taken into account. the influence of axial force on the reduced plastic moment capacity of a plastic hinge (mpc), is presented from the interaction between the bending moments and axial force based on exact interaction method that can be expressed for the box and i-sections, widely used in building frames. the exact interaction equations are al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٨ 1 f w 2 r r-1 r≤n xn-1m = (20) ( ) ( ) 1 f w 2 r r-1 rn n-1zn1ym >−−= (21) where yq q n = (22) p pc m m m = (23) q = axial force. qy = axial yield strength. mp = full plastic moment capacity of the cross-section. mpc = reduced plastic moment capacity of the cross-section due to effect of axial force. b t2 r ww = d t2 r ff = )r-1)(r-1(-1r fw1 = 2 fw2 )r-1)(r-1(-1r = 2w 1 2 rr r x = 2 1 r r2 y = 2 1 2 r r z = another method is the approximate interaction method for the influence of axial force on the reduced moment capacity of a plastic hinge (mpc), for w,s and m shapes can be expressed as (13)         −= y ppc q q 1m18.1m 15.0 q q ;when y 〉 ppc mm = 15.0 q q ;when y ≤ the effect of shear force on plastic moment capacity in general is much more complex than of axial force (14). in addition to causing beam-column instability (which is included in stability functions), the presence of shear force tends to reduce the magnitude of the plastic moment capacity of the section. the reduction of the plastic moment capacity of the cross-section in the presence of shear force is presented from the interaction among the bending moment, shear and axial forces. (30) (31) (32) (29) (27) (26) (25) (24) (28) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٢٩ the special case of an i-section was considered by baker and heyman (14) to show the effect of together shear and axial force on plastic moment capacity. the full plastic section modulus of an i-section is given by wt 2)ft2 d ()ft(dftfbpz ∗−+−∗= (33) pwzpfzpz += (34) where zp: the full plastic section modulus of the i-section. zpf, zpw: the plastic section modulus for the flanges and the web respectively. tf, tw: thickness of the flanges and the web respectively. d: depth of the i-section. it is commonly assumed in elastic design that the shear stress is uniformly distributed over the web of an i-section and the flanges not contributing at all to the carrying of shear force (14). baker and heyman (14) use these assumptions in plastic analysis and they gave the following equation for the reduced plastic section modulus for the web of an i-section due to the effect of shear and axial force ; pw 2 y 2 yw2 y z )f/(31 )(q/q )f/(τ31zw         τ− −−= (35) where, zw: reduced plastic section modulus for the web due to effect of shear and axial force. τ : shear stress. q: axial force. qyw: axial yield strength for the web (fy* aw). aw: area of the web. suppose that the reduction ratio for the web due to the effect of shear and axial force is equal to nc, thus, eq. (35) can be written as: zw = nc * zpw (36) to give the total reduced plastic section modulus, the flanges modulus (zpf) can be reduced due to the effect of axial force alone. the reduction ratio can be obtained from the exact interaction equations (15) as follows: (38) where: zpc: reduced plastic section modulus of the i-section due to the effect of axial force. 1r f r1 w rn2nx1 c m − ≤∗−= (39) 1 r f r1 wrn 2nx1 pz pcz −≤∗−= ( ) ( ) 1 r f r1 wrn 2 n1zn1y pz pcz −>−−−= )٣٧( al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٠ suppose that the reduction ratio due to effect of axial force is equal to mc, thus, eqs.(37 and 38) become ( ) ( ) 1 r f r1 wrn 2 n1zn1ycm − >−−−= (40) eqs. (37) and (38) can be written as: (41) zpc = mc * zp (42) zpc= mc (zpf +zpw) (43) zpc= mc * zpf + mc * zpw the second term of equation (43) can be replaced by eq. (36) to obtain a general interaction equation for the plastic section modulus for i and box sections including the effect of shear and axial force (zpcs), so equation (43) becomes: zpcs = nc* zpw + mc* zpf (44) where: zpcs: is the reduced plastic section modulus for box or isection due to the effect of shear and axial force. in terms of plastic moment capacity, equation (44) becomes: pfcpwcpcs m*mmnm +∗= (45) pcs m : the reduced plastic moment capacity for box or i-section due to the effect of shear and axial force. mpw, mpf: are the full plastic moment capacity for the web and the flanges respectively. the member stiffness relationships previously described for elastic large displacement analysis are based on the assumption that each member is rigidly connected to joints at both ends. when plastic (or real) hinges are presented, the relative member end rotations at the released ends are obtained from relative member force deformation relationships (eq.8 and eq.9 ) thus, for a member with plastic hinge at end 1 , 2 θ c c cei lm = 1 θ 1 _ 2 _ 1 _ 1pcs (46) for member with plastic hinge at end 2 1 θ c c cei lm 2 θ 1 _ 2 _ 1 _ 2pcs= (47) and for a member with plastic hinges at both ends ( ) ( )2112 2pcs21pcs1 1 cc mcmc ei l =θ (48) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣١ ( ) ( )2112 1pcs22pcs1 2 cc mcmc ei l =θ (49) in eqs.(46 to 49), the mpcs1 and mpcs2 are the reduced plastic moment capacity at ends 1 and 2 respectively. it may be seen that these equations (eqs.(46 to 49) which are developed in this study are written in general expression for the case of real (mpcs = 0) or/and plastic hinges. in the case of a member with a plastic hinge at one end and a real hinge at the other , the relative member end rotations ,θ1 and θ2 can be expressed in terms of mpcs1 or mpcs2 and c1 and c2 by using eqs.(48 and 49) with putting mpcsi = 0 for real hinge at end i .for example , for a member with a real hinge at end 1 and a plastic hinge at end 2 )2 2c _ 2 1c _ ( 2c _ ei pcslm 1 θ − −= (50) )cc( c ei pcslm 2 θ 2 2 _ 2 1 _ 2 _ − = (51) it may be noted that , for prismatic member with rigidly connected to joints at both ends the plastic moment capacities are equal for both ends. the tangent stiffness matrix in local coordinates , [t] , can be developed for a member with hinges by eliminating the released coordinate(s) from eqs.(8 to 10) and differentiating the resulting relations ,term by term ,with respect to the remaining coordinates. if incremental changes in plastic moment capacities are neglected, i.e. , plastic hinges are treated as real hinges, the nonzero elements of the 3x3 matrix, [t], are: for a member with a hinge at end 1 11z 12 2z 22 z 22 t −= (52) 11z 13z12z 23 z 32 t 23 t −== (53) 11z 13 2z 33 z 33 t −= (54) for a member with a hinge at end 2 22z 12 2z 11 z 11 t −= (55) 23z 23z12z 13 z 31 t 13 t −== (56) 22z 23 2z 33 zt 33 −= (57) and, for a member with hinges at both ends aelt33 = (58) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٢ in eqs. (52 to 57), [z] = the local tangent stiffness (denoted by [t] in eq. (15) for a member with no releases). the local tangent stiffness matrices as given by eq. (52 to 57) can be used for members with real as well as plastic hinges. as indicated previously, incremental changes in the plastic moment capacities are not included in eq.(52 to 57) (i.e.∆mpcsi = 0). in addition eq. (58) (for a member with releases at both at ends) assumes that the effect of incremental changes in the flexural bowing term on member axial force is negligible (i.e. ∆cb= 0). it should be noted that these simplifications are limited to the tangent stiffness matrices and do not extend to the system equilibrium equations. as the order of [t] is 3x3 even the presence of member releases, the transformations out lined in eq.(14) can be used to obtain the member tangent stiffness matrix [t] in the global system. soil-structure interaction in this study, the soil represents as isolated linear and nonlinear winkler-type springs at nodes of beam column element. the coefficient stiffness of spring is added to tangent stiffness matrix of structure in global coordinates. the modulus of subgrade reaction gives the relationship between the soil pressure and the resulting deflection. the behavior of the soil under compressive loading is nonlinear as verified by the results of plate load test in the field. the isolated nonlinear winklertype spring at nodes of a beamcolumn element can approximately be modeled using the two constant hyperbolic equation as shown in fig.(3), which takes the following form bδa δ p + = (59) ( )2n bδa a k + = (60) where p : the lateral load on beam-column element that is concentrated at the node. δδδδ : the lateral displacement of the node. kn : the normal subgrade reaction of soil. “a” and “b” are the physical parameters required for the hyperbolic equation, which can be obtained from the load-settlement curve of the plate-load test. in the present study, the negative stress of soil is not allowed in the analysis. so, the stiffness of tension force spring was not added to the total tangent stiffness matrix of structure. computational technique: most numerical schemes to solve nonlinear systems of equations are numerical-iterative processes that use a series of linear solutions to approximate the nonlinear solution. in the present study, the nonlinear response of the structures is generated by incremental load approach with the conventional newton-raphson type of iteration performed at each load level to satisfy the joint equilibrium. the computational technique is shown graphically in fig.(4) for a single degree of freedom system. to terminate the iteration process, a convergence criterion based on the displacement is used here through comparing the incremental change in displacement vector {∆x}, where the convergence is assumed to occur when the inequality al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٣ ( ) ( ) e x ∆x 2/1 i 2 i i 2 i ≤           ∑ ∑ (61) is satisfied simultaneously and independently for each group, where “e” represents prescribed tolerance which chosen here to be equal to 0.001. an important computational difficulty arises in determining member end forces m1,m2 and q, from the relative member deformations θ1,θ2 and u this is due to the fact that the expression for member axial force q, as given in eq.(10) involves bowing functions b1 and b2 , which, in turn, are functions of the axial force parameter q. in the presence of hinges, the problem is further complicated by the fact that rotations at the released ends (eqs.46 to 51) are also functions of q. the problem can be solved, however, by the following iterative procedure. noting that q , is only unknown in eq.(10) let: 0 l u bcq 2 λ 2 π k(q) =−+= − (62) let qi be an approximate of this equation. by using a first-order taylor series expansion,eq.(62) can be rewritten as in which a prime superscript denotes a differentiation with respect to q , and bc 2λ 2 π (q)k − ′+=′ (64) a new value is thus obtained for q: )i(qk )ik(q i q∆qq 1i q ii ′ −=+= + (65) moreover, the iteration continues until ∆q < e. in eq. (64) bc − ′ is given by ( ) ( ) ( )( ) )θθ)(θ(θb2θθθθb2θθbθθbc 212122121122122211b ′−′−+′+′++−′++′=′ −−−−− (66) in which, iθ′ terms = zero at member ends when rigidly connections to the joints. the rotations at such rigid ends are defined by the global joint displacements and remain constant during this iteration process. for a member with hinges, iθ′ terms at the released ends are given by differentiation of eqs.(46 to 51) with respect to q. thus, for a member with plastic hinge at end 1                     ′−+−′=′ 2 c 1 ccc c 2 θ c1pcs mc1pcs m cei l 1 θ 2 _ ' 1 _ 2 1 _ ' 1 _ 1 _ 2 1 _ (67) for member with a plastic hinge at end 2 0= i )∆∆ i (qk′+) i k(q=) i ∆q+ i k(q (63) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٤                         ′−+−′=′ 2c1ccc c 2θ c2pcsmc2pcsm cei l 2 θ 2 _ ' 1 _ 2 1 _ ' 1 _ 1 _ 2 1 _ (68) and for member with plastic hinges at both ends               + + −′ + =′=′ )2c _ 1c _ ( )2c' _ 1c' _ ( pcsmpcsm )2c _ 1c _ ei( l 2 θ 1 θ (69) in these equations the values of pcsm ′ can be determined by differentiating of reduced moment capacity with respect to the axial force parameter (q) for bending, axial and shear interaction (eq. (45)). cpfcpwpcs *m'mn'*mm' += (70) where 2 y ww c )f/(31 nn2 n τ− ′∗− =′ (71) yw w q q n = (72) yw 2 2 w ql eiπ n' = (73) 1 f wc r r1 rnn'nx2m −≤∗∗−=′ (74) 1 f wc r r1 rn)n1(n'z2n'ym −>−∗∗∗−∗−=′ (75) y 2 2 ql eiπ n' = (76) in the case of real hinges 0pcsm = and 0pcsm =′ numerical examples: a computer program (nepapfss) is developed in the present study to carry out the shear effect in large displacement elastic-plastic stability analysis of plane steel frames with members resting on elastic foundation . the computer program is coded in (quick-basic) language to be used on computers. the computer program consist of a main routine and many subroutines, each of these al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٥ subroutines has been designed to deal with a part of the analysis. in order to verify the reliability of this computer program and the effectiveness of the present formulation, some examples reported by previous researches are utilized. example no.1 represents a fixed-fixed beam resting on elastic foundation under uniform load. the geometry, load and material condition of this example is shown in fig.(5).the aim of this example is to illustrate the effect of the nonlinearity behavior of soil , shear deformation effect in the analysis of the structure .chen 1998 solved this problem assuming that the subgrade reaction of soil is linear. jawad 2002 re-solved this example assuming linear and nonlinear subgrade reaction. the same assumptions of above researchers for soil representation are used to re-analyze this example. a good agreement is achieved between the results of the present study and those obtained by chen 1998. the problem is presented in present work with six and eight elements considering the effect of shear deformation. table (1) gives the values of the mid-span deflection of the beam for previous works and the present study. the maximum percentage of shear effect for the midspan deflection is about (234.7٪) and (442.3٪) for linear and nonlinear spring behavior respectively. this shows the great role of shear deformation in increasing lateral deflection for linear and nonlinear soil analysis as shown in fig.(7). fig. (6) shows the deflected shape of this example for linear and nonlinear spring behavior with and without shear effect. example no.2 represents a fixed-fixed beam under concentrated load at mid span. the geometry ,load and material condition of this example is shown in fig.(٨). this case study is considered to check the effectiveness of the new interaction equation (eq.45) utilized in the present study which including axial, bending and shear interaction effects and to show the effect of considering shear interaction in the analysis. two types of steel sections are used w 12×31 and w14×426 (light and heavy sections respectively). zhou and chen 1985 gave the interaction curves for these sections based on the exact interaction equations eqs.(20 and 21)for the interaction between axial force and bending moment. in present study, the interaction curves for the above sections is plotted based on equation (45) for the reduced plastic moment capacity due to effect of together shear and axial force. from fig. (8) it can be seen that the ratio of (mpc/mp) is reduced about (11٪) from unity for light section and about (9٪) for heavy section when shear interaction is considered in the analysis. the full plastic moment capacity for heavy section is larger than the light section. thus; the reduction in the ratio (mpc/mp) due to shear effect for light section is larger than the heavy one. example no.3 represents a one-bay four-story frame resting on elastic foundation shown in fig.(9). the frame has been chosen for studying the effect of shear interaction in the analysis of frame structure when a base of the frame changes from a fixed base to elastic foundation by using steel embedded pile. in this study, this example is solved without including shear interaction by using approximate interaction method and including shear interaction to show the effect of shear on the behavior of structure. pile length is six meter. ten elements have been used for modeling the pile. the frame is analyzed for the value of the lateral load parameter (r = 0.5). the value of subgrade reaction of soil varies with the depth and the pile length is divided into two zones. the value of the subgrade reaction of the lower zone soil is larger than the upper one by 34% .the value of tangential modulus of subgrade reaction (ks) is equal to zero. the horizontal displacement of the top right joint of the frame versus the applied loading results obtained from the present analysis for all cases of this example as shown in figures (10) and (11). table (2) gives the results of present analysis. from the results obtained from all cases of this example, it can be seen that the ultimate load capacity decreases by a ratio (1.05-7.65) ٪ and the horizontal displacement of joint a increases about (3.18-6.1) ٪ when including shear effect in the analysis. the sequence of plastic hinges will be changed when the effect of shear interaction is taken into account. in addition, it may al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٦ be seen that using the elastic foundation supported instead of fixed support tend to reduce the ultimate load capacity about (0.16.67) . % conclusions: based on the results obtained in the present study, several conclusions may be obtained. these may be summarized as follows: 1. the large displacement elastic-plastic stability analysis of plane steel structures having members resting on soil and including shear effect can be accurately predicted using the beam column approach in the analysis. 2. a comparison between the results of linear and nonlinear behavior of soil obtained from elastic analysis shows that shear effect reached to (234.7٪) for linear soil behavior and about (442.3٪) for nonlinear soil behavior. 3. the ultimate load capacity decreases with a ratio (1.05-7.65) ٪ and the displacement increases with a ratio (3.17-6.1) ٪ when shear interaction is taken into account; in addition, the sequence of plastic hinges will change. 4. it has been found that using the elastic foundation supported instead of fixed support tends to reduce the ultimate load capacity with a ratio (0.1-6.67) ٪. 5. shear effect is governed by the value of shear flexibility parameter. in addition, the shear effect is more pronounced for members with small span to depth ratio. 6. from the above important conclusions, the effect of shear should be taken into account in the large displacement elastic-plastic analysis of structures having members resting on soil to get the real behavior of structures. references: 1. bowels, j. e., “foundation analysis and design.” mc graw-hill, international editions, fifth edition.1996. 2. aydogan .m., “stiffnessmatrix formulation of beam with shear effect on elastic foundation” journal of structural engineering, asce, vol.121, no.9, 1995, pp.1265-1270. 3. al-sarraf, s.z., “shear effect on the elastic stability of frames”, the structural engineer, vol. 64b, no. 2, june 1986, pp. 43-46. 4. eisenberger, m. and yankelevesky, d.z., “exact stiffness matrix for beams on elastic foundation “international journal of computers and structures, vol.21, 1987, pp.13551359. 5. al-hachami, e.k., “large displacement analysis of structures with applications of piles and submarine pipelines.” ph.d. thesis, university of technology, baghdad, 1997. 6. onu, g., “shear effect in beam finite element on two parameter elastic foundation” journal of structural engineering, asce, vol.126, no.9, 2000, pp.1104-1107. 7. jawad, f.a., “elastic-plastic large displacement stability analysis of plane steel frames with members resting on soil” m.sc. thesis, university of kufa, najaf, 2002. 8. sideek, k.f., “exact solution of the shear effect on the analysis of laced and battened beam-column “engineering journal of the university of qatar ,vol.18,2005,p.p.105-120. 9. timoshenko, s.p. and gere, j.m., “theory of elastic stability”. mc grow-hill book company, 2nd edition, 1961. 10. oran, c., and kassimali, a., “large deformations of framed structures under static and dynamic loads.” international journal of computers and structures, vol.6, no.6, 1976, pp. 539-547. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٧ 11. duan, l. and chen, w. f., “a yield surface equation for doubly symmetrical sections.” engineering structures, vol.12, april 1990, pp.114-119. 12. baker, j. and heyman, j., “plastic design of frames”. cambridge at the university press, 1969. 13. zhou, s. p. and chen, w. f., “design criteria for box columns under biaxial loading.” journal of structural engineering, asce, vol.111, no.12, 1985 pp.2643-2658. 14. chen, c. n., “solution of beam on elastic foundation by dqem.” journal of engineering mechanics, asce, vol.124, no.12, 1998, pp.1381-1384. table (1) the results of example no.1. type of support kn1 ton/in2 kn2 ton/in2 present study (without shear interaction) present study (with shear interaction) pu (tons) sequence of plastic hinges pu (tons) sequence of plastic hinges fixed base -------------------14.5 fig .(12-a) 14.306 fig .(12-a) elastic support (linear) 0.133 0.133 14.442 fig .(12-c) 14.29 fig .(12-b) elastic support ( nonlinear) a1=7.5 b1=0.029 a2=7.5 b2=0.029 14.429 fig .(12-d ) 14.028 fig .(12-e) elastic support (linear) 0.099 0.133 14.386 fig .(12-h ) 14.161 fig .(12-i) elastic support (linear) 0.133 0.179 14.458 fig .(12-f) 13.352 fig .(12-g) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٨ table (2) the results of example no.3 type 0f spring reference of the analysis number of elements mid span deflection (m) % effect of shear deformation 100*) δ1 δ1δ2 ( − without shear effect (δ1) with shear effect (δ2) l in ea r sp ri ng be ha vi or chen 1998 8 0.1812 ------ jawad 2002 7 0.1803 ------ present study 6 0.1861 0.6229 234.7 8 0.1865 0.6241 234.64 n on li ne ar sp ri ng be ha vi or al-rubai 10 0.208 ------ jawad 2002 10 0.210 ------ present study 6 0.214 1.1605 442.3 8 0.215 1.1584 438.8 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٣٩ . b q l γ φl v q v m m q l γl a fig. (1) element of length (l) of solid structural member under (a) bending (b) shear fig. (2) member end force and relative deformation for a beam-column element θ1 initial (undeformed) deformed u u lc =l u l θ2 q m1 m2 q kn(linear) = 1/a l oa d, p fig. (3) typical two constant hyperbolic equation to model the nonlinear soil behavior asymptote = 1/b deflection, δ al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٠ w= 1 kn /m, i = 1 m4 l = 3 m, a = 2.29 m2 a = 1 m2/kn, b = 10 m /kn fig. (٥) the geometry, soil properties and loading conditions of beam of example no.1 w l p∆ 1x∆ 2x∆ 3 x∆ pi+1 xi+1 τ fig. (4) computational technique. pi xi fig. (٧) deflected shape of example (٢) 0.5 1.5 2.50.0 1.0 2.0 3.0 distance from left end (m) -1.0 -0.6 -0.2 0.2 0.6 -1.2 -0.8 -0.4 0.0 0.4 d e f l e c t i o n ( m ) present study (non-linear spring) al-rubai (11) (non-linear spring) present study (linear spring) __________________________________ jawad (38) (linear spring) (8 elements) (8 elements) present study (linar spring with shear) present study (non-linear spring with shear) fig.(6) deflected shape with and without shear effect of example no.1 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤١ 0.2 0.6 1.00.0 0.4 0.8 1.2 mid-span deflection (m) 0.1 0.3 0.5 0.7 0.9 0.0 0.2 0.4 0.6 0.8 1.0 l oa d ( w ) ( k n /m 2) 6-elements (linear spring) 8-elements (linear spring) 6-elements (non-linear spring) 8-elements (non-linear spring) 6-elements (linear spring with shear) 8-elements (linear spring with shear) 6-elements (non-linear spring with shear) 8-elements (non-linear spring with shear) (k n /m ) fig.(٧) load-deflection curves of example no.1 p 54 in 54 in q /q y 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 ref.(71) (without shear interaction) present study (with shear interaction) ref.(71) (without shear interaction) present study (with shear interaction) w 12 x 31 (light section) w 14 x 426 (heavy section) fy =36 ksi fig.(8) interaction diagrams with and without shear effect of example no.2 21 21 mpc/mp al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٢ fig.(10) load-displacement curves for fixed base and constant normal subgrade reaction with and without shear effect of example no.3 fig.(9) the geometry, material and loading conditions of example no.3 columns w 12x79 (bottom story) w 10x60 (other stories) w 16x40 (all girders) lg = 30 ft lc =12 ft e=13 x 103 tsi fy=15.25 tsi 1 ton = 9.97 kn 1 in = 25.4 mm 1 ft = 12 in p p/2 p/2 p p p p/2 p/2 p/2 p/2 p/2 p/2 r p/2 r p r p r p (a) kn1 kn2 kn1 kn2 lg lc lg 0 5 10 15 20 25 horizontal displacement of joint a (in) 0 4 8 12 16 l o a d p ( to n s ) fixed base (1) without shear (2) with shear elastic support (linear,kn=0.133 ton/in ) (3) without shear (4) with shear elastic support (non-linear) (a=7.5 in /ton,b=0.029 in/ton) (5) without shear (6) with shear 1 2 3 45 6 2 2 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٣ fig.(12) sequence of plastic hinges at collapse load for all cases of example no.3 fig. (11) load -displacement curves for fixed base and variable normal subgrade reaction with and without shear effect of example no.3 1 2 3 4 5 10 7 8 (b) 6 9 1 5 2 3 4 6 7 (a) 5 1 2 3 4 6 (c) 0 5 10 15 20 25 horizontal displacement of joint a (in) 0 4 8 12 16 l o a d p ( to n s ) fixed base (1) without shear (2) with shear elastic support (linear) (kn1=0.133 ton/in ,kn2=0.179 ton/in ) (3) without shear (4) with shear elastic support (linear) (kn1=0.099 ton/in ,kn2=0.133 ton/in ) (5) without shear (6) with shear 1 2 5 63 4 22 2 2 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٤ 5 8 1 2 3 4 6 7 9 (k) (d) 8 6 1 2 3 4 5 7 8 10 1 2 3 4 6 7 5 9 (e) 6 1 2 3 4 5 (f) 7 (h) 1 2 3 4 5 6 7 8 (g) 5 1 2 3 4 7 6 fig. (١٢) continue al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٥ appendix a: 1.stability functions including shear effect 1.1 compressive axial force (i.e. q>0) (3) µq)(1ααtan )αcot2αµq)2(1(1α c1 − − − − −− −− − = − (a-1) )αcos2αµq)2(1αµq)(sin2)(1αα(tan ))αcot2αq)2(1α)(αsin2αµq)(2(1 2c −− −− − − − − − −− − −− − − − = − μμμμ (a-2) in which µq1 q 2 π q 2 π α − = − = − (a-3) µ : shear flexibility parameter. q : axial force parameter. 1.2 tensile axial force (i.e. q < 0) µq)(1ααtan )αcothαµq)2(1(1α 1c + − − − −− +− − = − (a-4) )αcosh2αµq)2(1αµq))(sinh2(1αα(tanh α)coth2αµq)2(1(1α)(αsinh2αµq)(2(1 2c −− +− − + − − − −− +− −− − − + = − (a-5) where µq1 q 2 π q 2 π α + = − = − (a-6) 1.3 zero axial force (i.e. q = 0) (19) 12µ2π 12µ24π 1c + + = − (a-7) 12µ2π 12µ22π 2c + − = − (a-8) 2.bowing functions including shear effect 2.1 compressive axial force (i.e. q > 0)(19)         − − − −− − −− +−− −− + −−− + − = − α22sin )αsin2α)(2ααcosα( 2 α22sin )αcos2αsin2α(2α2 2q44π 2)2c1c( 1b (a-9) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٦         − − − −−− − −− − − = − α22sin α)sin2α)(2αcos2α2α(2 2q48π 2 )2c1c( 2b (a-10) 2.2 tensile axial force (i.e. q<0)         − − − −− − −− +−− −− + −−− + − = − α22sinh )αsinh2α)(2ααcosh2α( 2 α22sinh )αcosh2αsinh2α(2α2 2q44π 22)c1c( 1b (a-11) (a-12) 3. the geometric matrices [g(k)] and the transformation matrix [b] (15,16) (a-13) 010 n 1 m 1 m m 1 n 1 n 001 n 1 m 1 m m 1 n 1 n b                         − δ+ − δ+ − − δ+δ+ δ+δ+ δ+ − δ+ − =     in which m = cosα , n = sinα         − − − −−− − −− − − = − α2 2 sinh )αsinh2α)(2αcosh2α2α(2 q248π 22)c1c( 2b                                   −− −− −− −− δ+ = 000000 02mmn02mmn 02mmn0mn2n 000000 02mmn02mmn 0mn2n0mn2n )1( 1)3(g                                     −−−− −−−− −−−− −−−− δ+ = 000000 0mn22n2m0mn2)2n2m( 02n2mmn20)2n2m(mn2 000000 0mn2)2n2m(0mn22n2m 0)2n2m(mn202n2mmn2 2)1( 1)2,1(g (a-14) (a-15) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٧ δ = u/l = (l – lc)/l α = the angle between the local and the global coordinates in the deformed configuration of the member. lc = the member chord length of deformed configuration. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٨ effect of compressive strength and reinforcement ratio on strengthened beam with external steel plate asst. lec. hesham abd al –latef numan civil engineering department, college of engineering al-mustansiriya university, baghdad, iraq abstract: the present study is an experimental comparison between the effect of increasing the compressive strength of the section and increasing the reinforcement ratio on the results of strengthening reinforced concrete beams with external steel plates of constant dimensions. the experimental program consists of testing ten reinforced concrete beams. five of them are without external steel plates to be the original specimens while the other five ones are provided with steel plates of same dimensions glued at the bottom face of the beams. three values of compressive strength (f'c) were used in this study which were (22, 45 and 71mpa) and also three ratios of internal reinforcement (ρ) which were (0.01411, 0.02116 and 0.03445) to investigate their effects on the strengthened beams behavior. the results showed that the cracking load and the ultimate load can be increased up to (150% and 137%) respectively. also, by increasing the section compressive strength all the properties of the strengthened beam can be improved while by increasing the reinforcement ratio the deflection and cracking can be reduced to improve the elastic behavior of the beam.. keywords: strengthened beam, external plate, deflection ductility, restraining. الحديد صفيحة من ب المدعمةالناتئة العتبةعلى ونسبة التسليحالقصوى تاثير قوى الشد الخارجية هشام عبد الطيف نعمان الجامعة المستنصرية كلية الهندسة :الخالصة ئج تقوية الدراسة الحالية عبارة عن مقارنة عملية بين تأثير زيادة مقاومة االنضغاط للمقطع وزيادة نسبة التسليح على نتا خمس . يتكون البرنامج العملي من فحص عشر عتبات خرسانية .العتبات الخرسانية المسلحة باستخدام صفائح فوالذية ثابتة األبعاد al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 377 computer aided design of rivets for steam boiler shells m.sc. farah kamil abid muslim dr. essam l. esmail department of mechanics department of mechanical engineering technical institute/ dewanya college of engineering, university of qadisiya dewaniya, iraq dewaniya, iraq farah_saleh77@yahoo.com dr.essamesmail@yahoo.com abstract most mechanical cad software used in mechanical design involves different types of decisions. all these decisions require coordinate-geometric and descriptive data. the objective of this work is to establish software programs for designing and analyzing rivets for boiler shells as an example to use rivets in industry. in general rivets are considered as mechanical elements of wide range application. a software program using visual basic version 5 with access database is used for design of rivets. when the user inters the input data to the system and depending on existing database, the software carries out a series of complex computations, after which it produces a comprehensive report that includes all engineering dimensions and efficiency. the program, designed in this research, has feasible ability to deal with data base in an easy and reliable way especially for unprofessional users. this is a database that can be updated and edited at any time to get proper results. the program can be applied also to different types of riveted joint. keywords: cad, mechanical design. boiler shell rivet access farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012378 nomenclature pb= back pitch c = constant, cad= computer aided design, d = rivet hole diameter, d1=rivet diameter, d = internal diameter of boiler shell, dxf= finite element method, l = shell length section, m = margin, n = number of rivets n= number of rows p = steam pressure in boiler, p= pitch, pt= caulking pitch, t = thickness of the boiler shell, tc= thickness of the cover plate σt = permissible tensile stress, σh= hoop stress, σl= longitudinal stress, σc= crushing stress, τ= shearing stress ηl= efficiency of the longitudinal joint, and η = lap joint efficiency. 1. introduction a rivet is a short cylindrical bar with a head integral to it. the cylindrical portion of the rivet is called shank or body and lower portion of shank is known as tail, as shown in figure1. rivets are used to make permanent fastening between the plates such as in structural work, ship building, bridges, tanks and boiler shells. the riveted joints are widely used for joining light metal. the boiler and pressure vessels are cylindrical in shape and withstand internal pressure. the cylindrical pressure vessel is identified by two dimensions, viz., the length and diameter. the cylinders are made from plates and whole length may not be obtained from single sheet hence cylindrical sections are obtained by bending sheets and joining edges by riveted joint. the sections are then joined together by another riveted joint along circumference. thus there are two types of joint longitudinal computer aided design of rivets for steam boiler shells 379 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 and circumferential (see figure 2). the longitudinal joint will bear hoop stress (σh) and circumferential joint bears longitudinal stress (σl). since σh = 2 σl, the longitudinal joint will have to be two times as strong as circumferential joint. therefore, longitudinal joints are always made butt joints whereas the circumferential joints are mode as lap joints. cad system were developed from simple graphic editors to be powerful systems that hold millions of standard part stored inside them with influent abolition to analyze, find design errors and identify weak point, in addition to powerful physical and analytical simulations that give exact solutions and accurate predictions. this paper is dedicated to build a software program which includes all the mathematical design considerations for boiler shell rivets. this software program generates the geometric design data. 2. literature review (casu and others, 1997) studied the structural behavior of a riveted joint during cooling after hot heading. they found that the semi-empirical formulation used for this purpose cannot justify the strength of the joint. they established that stresses inside the rivet and the jointed elements are lower than the yield point, differently from previous calculations. (citarella and gerbino, 2004) developed a cad/cae methodology for coupling design, oriented to an efficient integration, between cad systems and boundary element solvers, this methodology is based on a synergetic and strictly integrated usage of the pro/engineer cad system for geometric model generation, and. (hussam, wissam & baraa, 2005) built an automatic dimensioning procedure by creating a dxf format. the initial drawing and its dimensions are displayed automatically on autocad package window at one time. (haitham and others, 2004) introduced an educational software called eccentric loading. it is a user friendly and yet powerful tool for the analysis and design of riveted and bolted joints that are subjected to eccentric loads. (jarfall, 1986) made an attempt to review the state-of-the-art in procedures for designing and optimizing bolted or riveted joints. methods and data desired for the design procedure were defined and compared with what is available to day. following major steps in the design procedure were covered: calculation of the force distribution in the joint, which requires methods and data to account for fastener flexibility, eccentricities and bending support from surrounding structure; calculation of the fatigue quality or the fatigue life, which requires that the influence from bypass stress, load transfer and secondary bending on the fatigue performance must be known for various combinations of material qualities (of the joined members), hole qualities and fastener types. (maskow, 1985) reported that “the first successful beginnings towards rationalizing and humanizing” the structural assembly of civil aircraft, in this particular case in the production of riveted joints, have currently been made: a riveting system for spherically shaped aircraft frame structures has been specified, projected and tested for the assembly of aircraft shells. he described a 5axis-cnc riveting equipment, in which an optical sensor system provides the possibility of compensating variations automatically by means of component tolerances. (patronelli, 1999) remarked that numerous kinds of rivets have to be modeled for simulation of aeronautical framework crashes. for this kind of application, the authors modeled rivets with equivalent elements. failure mode of such elements was defined with a mixed shear/tension law. to characterize rivet failure under mixed mode loading, experiments and fe simulation of the arcan test procedure were undertaken with a 7050 aluminum alloy countersunk rivet. results showed that both approaches predict well the rivet failure criterion. moreover, fe tools also resolved design related problems of new riveted joint assemblies more rapidly and cost effectively than experiments. an analytical and optimization method was used to identify the parameter of a mathematical failure criterion of the riveted joint. 3. research methodology 3.1. data preparation: the necessary information for this system is shown in figure 3. they are: • type of joint (lap joint or butt joint) farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012380 • tensile stress (σt) • crushing stress (σc) • shearing stress (τ) • working pressure (p) 3.2. the developed system: this system is developed specifically to design and analyze rivet of boiler shell. the developed system can perform several functions as depicted in figure 3. each function interface with the other functions. 3.2.1. user interface: the user interface main module plays a key role in various system activities, by providing the possibility of accessing any part of the system. user interface is the communication mechanism between the user and other modules of the system. when the user enters the needed inputs through the user interface, the system designs and anglicizes the rivets of the boiler shell depending on the given inputs. 3.2.2. common database: the database must contain high level information about the product, because in such system we need common database that supports the user interface. this database consist of rivet-hole diameter and rivet diameter tables, type of joint, efficiency, and value of maximum pitch constant. 3.2.3. design and analyze module: to design boiler shell rivets and to determine the geometric design data, this will be done as following: 3.2.3.1. design of boiler shell rivets 1. design procedure for longitudinal butt joint  determine thickness of boiler shell (t) the efficiency of the joint is chosen from table 1 and for pressure σr, inner diameter d and permissible tensile stress σt, the thickness is calculated from, mm dp t lt 1 2 .     (1) the diameter and thickness will further guide in respect of rivet arrangement. table 2 can be used for this purpose.  determine rivet hole diameter (d) and rivet diameter (d1) unwin’s formula, giving d6√t is used if t ≥ 8 mm. in very rare case if t < 8 mm, d is calculated by equating shearing strength and crushing strength of rivet. the diameter of hole must be rounded off to the nearest standard value with the help of table 3, and the diameter of rivet also established.  determine pitch of the rivet (p) the minimum pitch is 2 d to accommodate the dies to form head. the pitch is calculated by equating tearing strength with shearing or crushing strength of rivet(s). however, the pitch should not exceed computer aided design of rivets for steam boiler shells 381 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 certain value for leak proof nature of the joint. the maximum value of p is given by following equation. mmtcp 28.41max  (2) the value of c is given in table 4. if by calculation p turns out to be less than pmax, it will be acceptable.  determine back pitch (pb) (a) for both lap and butt joints having equal number of rivets in different rows pb is given as: for zig-zag riveting, mmdpp b )67.033.0(  , (3) and for chain riveting mmdp b 2 (4) (b) for joints in which number of rivets in outer rows is half of that in inner rows which are chain riveted pb should be greater of the values calculated from equations (3) and (4). however, the value of pb for rows having full number of rivets will not be less than 2 d. (c) the third case arises for joints having inner rows zig-zag riveted and outer rows having half the number of rivets as inner rows where mmdpp b )15.12.0(  (5) the back pitch for zig-zag riveted inner rows will be: mmdpp b )67.0165.0(  (6) the pitch p in above equations is the one in outer row, i.e. away from butting edges.  determine thickness of the cover plate (tc) (a) for single butt cover with chain riveting: tt c 125.1 (7) (b) for single cover with pitch in the outer row being twice that in the inner row: t dp dp t c          2 125.1 (8) (c) for double cover of equal width and chain riveting: tt c 625.0 (9) (d) for double cover of equal width with pitch in the outer row being twice that in the inner row: farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012382 t dp dp t c          2 (8) (e) for double cover of unequal width (wider cover on the inside):      )outside on thecover for (625.0 )inside on thecover for (75.0 2 1 tt tt c c (11) determine margin, m = 1.5 d (12)  determine caulking pitch, pt the pitch of rivets in the row nearest to the edge must be as small as possible to avoid leakage. this pitch is called caulking pitch and helps edges to be caulked effectively (see figure 4). a rough rule is that this pitch should not be greater than stc. the caulking pitch is, however, calculated from following: 4/1 12 4/3 8.13  c c t dp  (13) this is an empirical relation in which σr the pressure is used in n/mm 2 . 2. design procedure for circumferential lap joint. the thickness of the shell, the diameter of the rivet hole, back pitch and margin are calculated in the same way as for longitudinal butt joint. the other quantities are presented under.  number of rivets (n) the rivets are in single shear and all of them are subjected to shear when pressure, σr acting on the circular section of the cylindrical space tends to separate two length sections of the vessel. so 22 1 44 ddn rs      and 2 1 2 d d n s r    (14)  pitch, (p) efficiency of the lap joint η can be taken as half of the efficiency of the longitudinal butt joint. the efficiency of the lap joint is calculated on the basis of tearing load capacity of the joint which turns out to be least of strengths in all modes. thus, p dp   (15)  number of rows, (n) the rivets are placed all along the circumferences of the shell. hence number of rivets in one row is ptdn )(1   hence total number of rivets in n n1 = n. )( td pn n    (16) computer aided design of rivets for steam boiler shells 383 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 whether the joint will be single riveted or multiple riveted will be decided by n. if n turns out to be less than 1, a single riveted joint will serve the purpose. in any case the pitch will have to satisfy the condition of caulking.  overlap of shell length section (l) mpnl b 2)1(  (17) 4. results and discussion to show the validity of our approach and for the purpose of completeness, an illustrative design example is introduced here. inner diameter of a boiler is (1500 mm) and the steam pressure is (2 n/mm 2 ).use a proper joint along the length and design it completely. the following permissible stress values will be used tension σt = 90 mpa shear σs = 75 mps crushing σc = 150 mpa  thickness of the shell (t) from table (2) for shell diameter of (1500 mm) a double riveted butt joint is recommended and from table (1)we can use an efficiency of (80%). 22mmsay 8.2118.201 8.0902 15002 1 2 mmmm d t t r        rivet hole diameter (d) mm 14.282266  td the nearest standard value of hole diameter is 28.5 mm, and corresponding rivet diameter is 27 mm. d1 = 27 mm.  pitch (p) in one pitch length there are two rivets which may shear or crush (figure 5). the shear strength of one rivet in double shear the crushing strength of one rivet the rivet is weaker in shearing. equating tearing strength of plate with shearing strength of 2 rivets in a pitch length, farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012384 check for maximum value of pitch from eq. (2). from table 4 for two rivets in a pitch length for a double cover double riveted joint the value of (c = 3.5). the min. pitch is 2 d. hence calculated value of p = 104.4 mm is acceptable. we may choose p = 105 mm. back pitch (pb) however, pb should not be less than 2 d or 57 mm pb = 57 mm. thickness of cover plate (tc) the joint has two equal cover plates. from eq. (9) margin (m) efficiency (η) the shearing strength of the joint the crushing strength of the joint the tearing strength of plate with holes the tensile strength of plate without holes computer aided design of rivets for steam boiler shells 385 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 ps is least of ps, pc and pt the application of the proposed system is introduced here. figure 7 shows the proposed input frame and the result .by entering the following data(inner diameter of a boiler, steam pressure, tensile stress, crushing stress, and shearing stress), and by using the type of joint and efficiency database in figure 8 and 9, the results are thickness of the shell (t). figure 10 shows the calculation of rivet hole diameter (d) and rivet diameter (d1) that depends upon the corresponding rivet diameter database as shown in figure 11. figure 12 shows the proposed input frame and the result .by entering the following data (number of rivet in one pitch length) ), and by using the value of constant for maximum pitch from database in figure 13, the results are (shear strength of one rivet, crushing strength of one rivet, pitch, maximum pitch, and back pitch). figure 14 shows the calculation of (thickness of cover plate (tc), margin (m), shearing strength of the joint, crushing strength of the joint, tearing strength of plate with holes, tensile strength of plate without holes, and efficiency) 4. conclusions in this study, software is developed for automating the design analysis of rivets for boiler shells. the aim of the development of this software is to present a method for effective use of general purpose programs in the design analysis. the software developed is then used for evaluating the effects of design parameters on rivet of boiler shell characteristics. the program is composed of user interface, which is composed in visual basic 5.0 with access database for design rivet, includes the forms for data input and result output procedures. it is a userfriendly and yet powerful tool for the analysis and design of rivet of boiler shell. the user starts the application by specifying his input data as one of the following (inner diameter of a boiler, steam pressure, tensile stress, crushing stress, and shearing stress), by using the database, the results are (thickness of the shell, rivet hole diameter, rivet diameter, thickness of cover plate, margin, shearing strength of the joint, crushing strength of the joint, tearing strength of plate with holes, tensile strength of plate without holes, and efficiency). with such a broad field of application, it would be expected that students of engineering as well as practicing design engineers will find this system to be a powerful tool that facilitates the accurate analysis and design of riveted or bolted joints of the lap or butt type. farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012386 referencees casu a; fregonese r; garro a; calderale pm., mechanisches verhalten von heissnietverbindungen in abhangigkeit von abkuhlung und creep, stahlbau. v 66, n 1, jan 1997, p 12-19. citarella and gerbino," be analysis of polygonal profiles shaft-hub couplings", 2004. hussam, wissam & baraa," an integrated approach to design and analyze unprotected type flange coupling", al-taqani, vol.18, no.2, 2005. haitham, and others, “an interactive software for the design of riveted joints", 2004. jarfall, l., shear loaded fastener installations, int. j. vehicle design. 1986. vol. 7, no. 3-4, pp. 337-380. kemal çaliskan," automated design analysis of anti-roll bars", september 2003 maskow, j., use of automated riveting systems in aircraft construction, 30. national sampe symposium and exhibition, anaheim, ca (usa), 19-21 mar 1985. patronelli, l; markiewicz, e; langrand, b; deletombe, e; and drazetic, p., analysis of riveted joint failure under mixed mode loading, european journal of mechanical and environmental engineering. v 44 n 4, winter 1999, p 223-228. computer aided design of rivets for steam boiler shells 387 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 table 1 efficiencies of commercial boiler joints type of joint average efficiency % maximum efficiency % lap joints single riveted double riveted triple riveted 45-60 63-70 72-80 63.3 77.5 86.5 butt joints single riveted double riveted triple riveted quadruple riveted 55-60 70-83 80-90 85-94 63.3 86.6 95.0 98.1 table 2 suggested rivet arrangements dia. of shell (mm) thickness of shell (mm) rivet arrangement 610-1830 6-12.5 double riveted 915-2130 8-25.0 triple riveted 1525-2740 9.5-31.75 quadruple riveted table 3 standard rivet hole and rivet diameters d (mm) 13 15 17 19 21 23 25 28.5 31.5 34.5 37.5 41 44 d1 (mm) 12 14 16 18 20 22 24 27 30 33 36 39 42 table 4 the value of constant for maximum pitch number of rivets lap joint butt joint single cover butt joint double cover 1 1.31 1.53 1.75 2 2.62 3.06 3.50 3 3.47 4.05 4.63 4 4.17  5.52 5   6.00 farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012388 figure 1 rivet parts figure 2 longitudinal and circumferential location for riveted joints figure 3 system architecture computer aided design of rivets for steam boiler shells 389 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 figure 4 caulking of riveted joint figure 5 farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012390 figure 6 flowchart for design procedure of longitudinal butt joint start input inner diameter of a boiler, steam pressure, tensile stress, crushing stress, shearing stress, and number of rivet in one pitch length calculate thickness of the shell calculate rivet diameter geometric data report type of joint database efficiency database calculate rivet hole diameter corresponding rivet diameter database calculate shear strength of one rivet calculate crushing strength of one rivet calculate pitch calculate maximum pitch calculate back pitch constant of maximum pitch database calculate tensile strength of plate without holes calculate thickness of cover plate calculate margin calculate shearing strength of the joint calculate crushing strength of the joint calculate tearing strength of plate with holes calculate efficiency computer aided design of rivets for steam boiler shells 391 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 figure 7 calculate thickness of boiler shell frame figure 8 type of joint database frame figure 9 efficiency database frame farah kamil abid muslim, essam l. esmail al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012392 figure 10 calculate diameter of rivet frame figure 11 rivet diameter database frame figure 12 calculate pitch of rivet frame computer aided design of rivets for steam boiler shells 393 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 377-393, year 2012 figure 13 value of constant for maximum pitch from database frame figure 14 calculate efficiency frame developing expert system for operating haditha dam al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 1 developing expert system for operating haditha dam nariman yahya othman, e-mail:www.nariman81 @yahoo.com ass. instructor, civil engineering department engineering college, babylon university this search presents the development and application of an expert system for operating haditha dam, which is considered the second biggest dam in iraq. haditha dam is a multi – purpose hydro – development designed to control the euphrates river flow in the interests of irrigation, electric power generation and for partial accumulation of extreme euphrates river inflows into haditha reservoir. haditha dam was constructed on the euphrates river in the middle west of iraq (8km) upstream from haditha town. in 1988 the project was completed. central and southern parts of iraq get the benefit of irrigation water from its reservoir. it is consist of the body of the dam, hydro-power station generates (660 mw) from (6 generator units), spillway with (6 opening controlled by radial gates) and two bottom outlets. ministry of water resources denoted that year (2009) is a drought year for that reason the good management for water resources is very important. haditha dam was taken as case study because the important of the project and its [water level elevation became (116 m.a.s.l.) for the mentioned year while its dead water level is (112 m.a.s.l.),(g.s.d.r.),(2012)] which means that the reservoir is almost empty, where the hydro-power station is stopped for (4 months) (from 9/2009 to 12/2009) and the release was just from the bottom outlets. therefor an expert system is developed to operate the dam. expert system (es) is a branch of artificial intelligence (ai) that has achieved considerable success in recent years. the area of expert systems involves investigation into methods and techniques for constructing human-machine systems with specialized problem solving expertise. expert system has many applications in the field of water engineering such as construction, design, planning, operation and maintenance of hydraulic structures. the language used to program the expert system in this search is (visual basic) program within windows environment. the expert system has developed depending on actual data for operating dam for (21 years) from 1991 to 2011),[g.s.d.r.,(2012) ]. it is found that using the developed expert system for operating haditha dam monthly and daily was very efficient where randomly the measured average monthly water levels for (10/1991) and (9/2011) were (136.95 and 135.72, respectively) while the calculated by the program (136.80 and 135.59, respectively) were the results calculated showed that the difference between the calculated water levels and the measured water levels was as average (15 cm) which means that the development of expert system is correct. key words: dam, operation, expert, system, haditha, operation rules. تطوير نظام خبير لتشغيل سد حديثة ناريمان يحيى عثمان مدرس مساعد , قسم الهندسة المدنية كلية الهندسة , جامعة بابل developing expert system for operating haditha dam 2 حيث يعتبر ثاني اكبر سد في العراق. تم وألهميتهالبحث يتناول تطوير وتطبيق نظام خبير لتشغيل سد حديثة , الري و ألغراضعلى نهر الفرات واالستفادة من مياهه تصميم سد حديثة كسد متعدد االغراض اهمها السيطرة توليد الطاقة الكهربائية و خزن المياه في خزان سد حديثة. كلم عن مدينة حديثة وتم االنتهاء من تشييده عام 8تم انشاء سد حديثة في الغرب االوسط في العراق ويبعد ي في السد الغراض الري يتالف السد من جسم تستفيد المناطق وسط وجنوب العراق من المخزون المائ 8888 فتحات 6وحدات توليد و مسيل مائي يحوي على 6ميكا واط ( متألفة من 666السد ومحطة كهرومائية بقدرة ) الى منفذي تفريغ . باإلضافةمسيطر عليها بواسطة بوابات شعاعية جب ايجاد ادارة جيدة للموارد المائية في القطرر هي سنة جفاف ولذلك يستو 9668اعلنت وزارة الموارد المائية عام ( بسبب اهمية السد ولكون منسوب الماء في السد للسنة المرذكورة قرد كحالة مدروسة) . وقد تم استخدام سد حديثة فرروق مسررتوح 889فرروق مسررتوح سررطر البحررر( فرري حررين ان المنسرروب االدنررى للسررد ) 886وصررل الررى منسرروب ) وذلررررك يعنرررري ان خررررزان السررررد كرررراد ان يفررررر , وان المحطررررة (( 9689ود و الخزانررررات, ))هيئررررة السرررردسررررطر البحررررر ( وكررران االطررر ق فقرررط مرررن منافرررذ 9668/ 89و لغايرررة 9668/ 8الكهرومائيرررة ترررم ايقافهرررا لمررردة اربعرررة اشرررهر مرررن الرذي اثبرت و التفريغ ولذلك تم تطوير نظام خبير لتشغيل السد. و النظام الخبير هو احد فررو الرذكاء االصرطناعي نجاح في السرنوات االخيررة وباالعتمراد علرى مسراحة التحريرات للحالرة المدروسرة لعمرل نظرام يحراكي الخبررة البشررية لحل المشاكل في المجاالت المختلفة. تم تطبيق نظام الخبير في الكثير من مجاالت الهندسة المائية كاإلنشاء والتصميم و التخطيط والتشغيل واالدارة الهيدروليكية وقد تم استخدام لغة ) فيجوال بيسك ( لبرمجة نظام خبير ضمن بيئة ويندوز وتم تصميم للمنشآت و السدود )هيئة 9688ولغاية 8888سنة من 98للسد خ ل النظام الخبير بناءًا على بيانات تشغيلية حقيقية النظام باستخدام( والتي تم التوصل اليها حيث كانت النتائج التشغيلية ) الشهرية واليومية (( 9689, )الخزانات لشهري المقاس فمث عشوائيا كان معدل منسوب الماء الخبير مقاربة جدا مقارنة مع البيانات التشغيلية للسد المنسوب المحسوب لكل شهر كما يلي ( بينما كان891.39( و)896.81كما يلي)( 86/9688( و )8/8888) وب المياه المقاس كمعدل ن الفرق بين منسوب المياه المحسوب مع منسحيث كا ( 891.18( و )896.86) ( سم مما يدل على صحة بناء النظام الخبير. 81) 1. introduction water is a very important resource, which makes its management one of the greatest challenges facing us globally; therefore, the human beings constructed dams to have a most benefit from water. haditha dam is an earth-fill dam on the euphrates river, north of haditha, creating lake haditha. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 3 the purpose of the dam is to generate hydroelectricity, regulate the flow of the euphrates and provide water for irrigation. it is the second-largest hydroelectric contributor to the power system in iraq behind the mosul dam. all that mentioned above show the importance of good dam operation. since reservoir operation involves very complex decision-making processes; thus, an expert system will be very efficient to make the decisions of operation. artificial intelligence is the science of making machines do things that would require intelligence if done by men (kumara and soyster (1986)). expert system is a branch of artificial intelligence that makes extensive use of specialized knowledge to solve problems at the level of a human expert. it is an intelligent computer program that uses knowledge and inference procedures to solve problems that are difficult enough to require significant human expertise for their solution. expert system depends on the knowledge acquired from human experts. the user supplies facts or other information to the expert system and receives expertise in response. internally, the expert system consists of two main components. the knowledge base contains the knowledge with which the inference engine draws conclusions. these conclusions are the expert system's responses to the user's queries for expertise (giarratano and riley (1962)).the knowledge of an expert system may be represented in many ways. it can be encapsulated in rules and objects. one common method of representing knowledge is in the form of if... then type rules. expert systems have experienced tremendous growth and popularity since their commercial introduction in the early 1980s. expert systems have been applied to many fields of knowledge such as: chemistry, electronics, medicine, engineering, and geology. the use of expert system has many advantages including increased availability of expertise at reduced cost, reduced risk, improved permanence, the use of multiple expertise, increased reliability, fast response, availability of intelligent tutor, intelligent database and steady, unemotional, and complete response at all times. however, lack of knowledge and expertise is considered the main limitation of building expert systems (giarratano and riley (1962)). 2. the previous researches (simonovics , s. p. (1990)) in his paper discussed issues involved in both phases of the development of an expert system for flow measurement method selection. where development of the system was done in two phases with very different emphasis. during the first phase, the emphasis was on the selection process, while during the second phase logic control was the major issue. the advisory system for flow measurement method selection has been designed to aid the user in the selection process . two aspects of selection are considered: physical characteristics of the gauging site and/or structures at the gauging site. the system has been designed for potential use by environment canada. (mohan, s. and arumugam, n. (1995)) presented a hybrid expert system that has been developed for operation of a tank irrigation system in south india. the heuristics and optimal knowledge are integrated with algorithmic techniques to operate the system under real-time conditions. (varas, e.a. and chrismar, m. v. (1995)) presented an expert system to help select the best method to estimate design flood flows for civil engineering works based upon the procedures available, the nature and characteristics of the basin and existing hydrological records. the system presents the user with a list of possible methods ranked in descending grade order and optionally presents explanations which support the selected choices. ordering is achieved using the knowledge base provided by the expert. the system recommends procedures for both preliminary estimates and final designs. the system also constitutes a valuable aid for junior engineers and experienced hydrologists in the selection of methods. its conceptual structure can be easily generalized to treat other problems of a similar nature in the field of hydrology and water resources. (al-matlabie, a.h. (1999)) produced the expert system (esorsa) which means (the expert system for operation of the multi-purpose reservoir system of al-adheem dam), where this system developed to give the advice to operate the reservoirs depending on the knowledge of the developing expert system for operating haditha dam 4 experts and the previous researches on operating reservoirs, al-adheem reservoir is used as a case study. the researcher focused to optimize the operation of the multi-purpose reservoir system using the (dddp)(discrete differential dynamics programming) to prevent flood, provide water requirements and generating electric energy from the hydro-power station. the (esorsa) built by (crystal) which is software has the ability of taking knowledge. (tospornsampan , j., kita, i. , ishii, m. , and kitamura, y. (2005)) proposed and developed a combination of genetic algorithm and discrete differential dynamic programming approach (called ga-dddp) which is used to optimize the operation of the multiple reservoir system. the demonstration is carried out through application to the maeklong system in thailand. the objective of optimization is to obtain the optimal operating policies by minimizing the total irrigation deficits during a critical drought year. the performance of the proposed algorithm is compared with the modified genetic algorithm. the results show that the proposed ga-dddp provides optimal solutions, converging into the same fitness values within a short time. the ga is able to produce satisfactory results that are very close to those obtained from ga-dddp but required a lot more computation time to obtain the precise results. the difficulties in selecting optimal parameters of ga as well as finding a feasible initial trial trajectory of dddp are significant problems and timeconsuming. the significant advantage obtained from ga-dddp is saving of computational resource as ga-dddp requires no need for optimizing parameters and deriving feasible initial trial trajectories. because dddp is a part of ga-dddp, the good performance of ga-dddp is obtained when applied to a small system where numbers of discretization and variables have no influence to the dimensionality problem of dddp. (emiroglu, m. e.(2008)) the objective of his study is making expert system to discuss the factors influencing the selection of the type of dam by giving examples from rules of thumb and also to present typical cross sections for types of dams to be constructed on different foundations. (swart, h. s. ,van rooyen, p. g. , mwaka, b. and ntuli, c. (2009)) purposed in his assessment general and drought curtailment rules for the major dams situated within the great marico river system. the climate of the marico catchment is semi-arid with the result that flow in the marico river is highly variable and intermittent. the water resources yield model (wrym) was used for the historic as well as the longer and short-term stochastic yield analyses that were undertaken for each of the major dams. (abd-elhamid, h. f., javadi, a.a. negm, a.m. elalfi,a.e. and owais,t.m. (2011)) developed expert system for maintenance and repair of masonry barrages. the clips 6.0 software was used for building the expert system and a user interface was implemented using visual basic 6.0. the advantages of using an expert system are that facts and rules can be easily modified to respond to changes and new rules can be added to deal with unconsidered problems. the developed expert system can help users to identify the possible causes of problems and suggest a suitable method of repair. the proposed system was verified using field data collected from mwri for barrages on the nile river in egypt. the use of the proposed expert system will save time in the process of taking maintenance decisions and will help in making the expected life of the structure as long as possible. 3. case study the dam is situated in a narrow stretch of the euphrates valley where a small secondary channel branched off the main channel. the width of the main channel was (350 m) whereas the secondary channel was (50 m) wide. the hydroelectric station is located in this secondary channel. the haditha dam is (9,064 m) long and (57 m) high, with the hydropower station at (3,310 m) from the dam's southern edge. the crest is at (154 m.a.s.l.) and (20 m) wide, (kamnev, n. m.; sonichev, and n. a.; malyshev, n. a. (1984)). in cross-section, the dam consists of an asphaltic concrete cutoff wall at its core, followed by mealy detrital dolomites, and a mixture of sand and gravel. these materials were chosen because they are readily available near the construction site. this core is protected by a al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 5 reinforced concrete slab revetment on the upstream side of the dam, and a rock-mass revetment on the downstream side, (kamnev, n. m.; sonichev, and n. a.; malyshev, n. a. (1984)). the power station contains six kaplan turbines capable of generating (660 mw). the turbines are installed in a hydro-combine unit that comprises both the spillway and the hydro-power plant in one structure. maximum discharge of the spillway is (11,000 m 3 /s) ),[g.s.d.r.,(2012) ]. two bottom outlets on the dam can discharge (3,000 m 3 /s) irrigation. both these outlets and the spillway are controlled by radial gates iraqi ministries of environment, water resources and municipalities and public works (2006) haditha reservoir has a maximum water storage capacity of (8200 million m 3 ) and a maximum surface area of (500 million m 2 ). actual capacity is however (6591 million m 3 ), at which size the surface area is (415 million m 2 ), [g.s.d.r.,(2012) ]. the details of the dam data which are required for the expert system are tabulated in (tables 1, 2, 3, 4, 5, 6 and 7). 4. mathematical model for the operating haditha dam reservoir's two curves represented (the upper rule and the lower rule for operating haditha dam, figure 1, which is produced by(ali, a.a.,(1994)) (ali, a.a. is prof. phd in water resources engineering ) he used one of the best mathematical models (dddp) (discrete differential dynamic programing) for representing the previous curves where he found the upper value of storage for haditha reservoir and the lower value of storage for each month, therefore the program of (expert system for operating haditha dam) (esohd) is based to make sure that the storage in the reservoir will be no more than the upper rule and not less than the lower rule, in normal and flood operation and made the storage not less than the minimum storage in the drought operation, the equations used to reach that aim , are: water balance equation for monthly operation: sm (i,j+1)=sm (i,j)+[i(i,j)-o(i,j)]*t+[p(j)-e(j)]*a(i,j) (1) where: j=no. of months :1,2,…,12 i=1,2,…,n and for daily operation: s d(k,l+1)=sd (k,l)+[i(k,l)-o(k,l)*t+[p(k)-e(k)]*a(k,l) (2) where: l=no. of days according to the month:1,2,…,(28,29,30,31days) k=1,2,…m where: sm(i,j)=average monthly storage,(m 3 ). i(i,j)=average inflow to the reservoir,(m 3 /s). o(i,j)=average outflow from the reservoir,(m 3 /s). p(j)=average monthly precipitation,(m). e(j)=average monthly evaporation,(m). a(i,j)=surface area of reservoir,(m 2 ),where it is change with elevation of water in the reservoir. t = period of time,(s). n =no. of operating years. where: s d(k,l)=daily storage,(m 3 /s). developing expert system for operating haditha dam 6 i(k,l)= daily inflow to the reservoir for day(l) and month(k),(m 3 /s). o(k,l)=average outflow from the reservoir for day(l) and month(k),(m 3 /s). p(k)=average monthly precipitation on the reservoir,(m). e(k)=average monthly evaporation from the reservoir,(m). a(k,l)=surface area of reservoir (for day(l) and month(k),(m 3 /s),where it is change with elevation of water in the reservoir. t =period of time,(s). n =no. of operating months. (ishaq,(1998)) produced two equations representing the relationships between volume with water level and surface area with water level, fig. 2 represent the previous relationships, the two equations are: v=0.24114(elev-100.062) 2.7114 (3) with r 2 =0.99553 a=0.000588(elev-81.992) 3.252 +37.018 (4) with r 2 =0.9947 the limits of these equations are (110-150) m.a.s.l. a. operating the power station is related directly by the water requirements downstream the dam where the release from the dam is used for operating by the power station to generate electric power then the excess water will be released from the bottom outlets or from the spillway if the water level in the reservoir is above the crest level of the spillway. to calculate the production power , ( ali, a.a., (1994)) produced: p= (9.81 * qp* hn*e*10 -3 ) (5) where: p= power production , ( mw). qp = discharge the station , ( m 3 /s ). hn = net water head ( m ). e = efficiency of the generated units (0.9). hn = hg – hl (6) where: hg = gross water head ( m ). h1 = losses in head ( m ). h1 = 3.0 m , ( ali ,a.a., ( 1994)) hg = uswl – dswl (7) where: uswl = is the elevation in the reservoir ( m.a.s.l. ) dswl = is the water level downstream the dam , ( in the river), ( m.a.s.l.) downstream water level can be calculated by : al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 7 dswl = 0.14063886 * ( q + 919.4654 ) 0.56108517 + 94.049683 (8) this equation is produced by (ali, a.a., (1994)). where: dswl = downstream water level ( in the river ) , ( m.a.s.l.). q = the total discharge (release) from the dam, (m3/ s). the limits for this equation are water level elevation (118 – 129.5) (m.a.s.l.) where (118) is enough to operate just one unit from the power station while 129.5 is the minimum operation elevation enough to operate the all six units. b. operating the bottom outlets means finding gate opening of the bottom outlets with required specific discharge depended to reach that aim, a diagram represent the relation between ( discharge and gate's opening, figure 3, the diagram have (8 curves) each curve represent a special water elevation . after analysis of the diagram ( 8 equations produced ) to represent each one of the curves to find the gate opening as shown in figure 4 and for other water elevations a ( linear interpolation) can be down , the equations are: opeb1 =( qb11.921)/45.108 (9a) with r² = 0.9854 opeb2 = ( qb 12.929) / 71.624 (9b) with r² = 0.9892 opeb 3= ( qb 11.723) / 127.31 (9c) with r² = 0.9876 opeb4= ( qb 12.22) / 163.14 (9d) with r² = 0.9907 opeb5 = |(qb + 14) / 220.8 (9e) with r² = 0.99 opeb6 = (qb+ 22.352) / 247.8 (9f) with r² = 0.9889 opeb7 = (qb+ 9.3514) / 255.53 (9g) with r² = 0.9855 opeb8 = (qb+ 1.2505) / 264.18 (9h) developing expert system for operating haditha dam 8 with r² = 0.9788 figure 4 showed that the fitting curves are linear while the real curves are almost linear but the results of r² are very high therefore the obtained equations are used. c. operation of the spillway means finding the opening gate of the spillway for a specific discharge, (aljanabi, w.k.k.,(2004)) produced a very efficient mathematical procedure to calculate the gate opening and as follows: 1. specified the released discharge from spillway (qsp). 2. calculating (hsp) depending on the water level in the reservoir. 3. calculating (cd) depending on (hsp) and assuming of the open of gate (a) by using the relationship shown in figure 5. 4. after finding (hsp) and the values of (cd) then spillway flow equation can be used as follows: a = qsp / cd *ng*b*√2ghsp (10) the previous steps are repeated until having good agreement between the calculated and the assumed open gate. where: qsp = discharge (m 3 / s) a= opening the gate (m) cd = discharge coefficient ng = number of gates b = width of one gate (m) g = acceleration gravity (9.81 (m / s)) hsp = operating head upstream the gate ( m ). 5. mechanism of operating haditha dam by using the expert system (esohd) the style and mechanism for operating haditha dam have been developed using latest scientific technology ( artificial intelligence ) represented by expert system which programmed using up to date programming language ( visual basic ) within windows environment the expert system has developed on analyze of real working data from 1991 to 2011 and as follows: 1the first window of (esohd) is the main menu demands the user to enter his name and choose the type of operation (daily or monthly) by choosing one of the options, as shown in, figure 6 and 10. in the same window the button “help" showed the help window figure 14 and button "exit" will end the program. 2-1 for the monthly operation the second window figure 7 will appear when (option one is chosen and welcome the user by his name and demand him to enter the required data which are (the file name including (average monthly inflows (m3/s) for the required period of time) the initial outflow (release), the average monthly precipitation and the average monthly demand (m 3 )), the no. of years required for operating and the initial water level (m.a.s.l.). 2-2 after entering the required data ("the result "button) must choose to make the program calculating the required results and as the following mechanism: al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 9 a. the first storage s (1,1) and the first surface area a (1,1 ) by equation ( 4-3 ) depending on the first entered measured water level , then ( the water balance equation ( 4-1 ), will calculate the storage for one of the next months, for each year the last storage s ( i , 12 ) will be the first storage s ( i+1, 1) for the followed year. b. the calculated storage will be compered by the [upper rule (sup) and lower rule (slow) of (ali, a.a., (1994))]. if the storage s(i,i) more than (sup) for that month then the program will take it equal to the (sup ) and if the s(i,i) is less than the(slow) then the program will take it equal to the (slow) then the program will calculate a new ( water level eq.(4-3) and release from eq.(4-1) according to the correct storages. c. the program (esohd) will sure that the calculated releases (rel (i,i)) are not excess on the maximum river capacity and not less than the water demands for each month. d. then the storage will be calculated again by eq.(4-1) according to the corrected releases and compered with smax ( not more than it ) and ( not less than smin). e. calculated depending on the amount of release in step (b.). if the release is more than the capacity of the power station (2034 m 3 /s),), [g.s.d.r.,(2012) ] then the power station will take just the enough discharge and the excess water will be released from bottom outlets or from the spillway, while if the release is less than the capacity of the power station then the power station will take all the release for its operation, if the water level in the reservoir is enough . f. then (esohd) will calculate [dswl by eq. (4-8), hg by eq. (4-7), hn by eq. (4-6) to find the production power (mw) (p) by eq. (4-5)]. g. all the steps above will be return for the daily operation, if (option two) will be chosen except eq (4-2) will be used instead of eq (4-1) as water balance equation. h. at last the second window figure 7 have another two buttons ( "main menu" which return the user to the main menu window if he want to change the option and "exit" button to end the program). 3the results of the monthly operation will appeared in window three figure 8 where the [ calculated storage ( million m 3 ) , calculated water level ( m.a.s.l.) , release ( m 3 /s) , dswl ( m.a.s.l.) and the prediction power ( mw)] will be listed for each year . the results window having four control buttons [ " back" ( which able user to return to the previous window ) , " main menu" ( able the user to return to the first window ( main menu)), " details of operation " ( which open new window to show the user how to operate the structures of the dam ) and "exit" to end the program]. 4the fourth window is the (details of operation window) figure 9 when the user click on any year in the ( results window) then the program ( esohd ) will show the user the mechanism of operating each part of the dam ( power station , bottom outlets depending on equations (4-9(a-h)) and/or the spillway depending on equations (4-10) for each month and for the specific year. 5for daily operation all the steps above will be returned and figures 10, 11, 12 and 13 will show the mechanism of operating. 6. the results the results obtained by running (esohd) for the monthly operation for the total period (1991-2011) are listed in tables 8, 9, 10, 11 and 12(water level (m.a.s.l.), release (m 3 /s), storage (million m 3 ), production power (mw ),and dswl (m.a.s.l.)),it is found: developing expert system for operating haditha dam 11 1. the maximum calculated storage is (8339.8 million m 3 ) where it is less than the maximum storage of the reservoir (9850 million m 3 ) while the minimum storage was (474.0 million m 3 ) for (the drought year) which is more than the minimum storage of the reservoir (188 million m 3 ). 2. the maximum calculated water level is (147.27 m.a.s.l.) where it is less than the maximum water level of the reservoir (150.2 m.a.s.l.) while the minimum water level was (116.46 m.a.s.l.) which is more than the minimum water level of the reservoir (112 m.a.s.l. ). 3. the maximum calculated release is (1163 m 3 /s) which is less than the maximum capacity of the river (4730 m 3 /s) while the minimum calculated release was (188 m 3 /s) which is more than the minimum discharge of the river (70 m 3 /s). 4. the maximum power production was (520.4 mw)less than (660 mw) while the minimum power production was (0.0 mw) where the power station stopped for three months in (the drought year) because the water level was less than (118 m.a.s.l.) which is the minimum elevation of water can operate one turbine of the power station and the release was just from the bottom outlets. 5. the spillway has not operate all the period of time and that because all the releases for each month are less than the maximum capacity of the power station therefor they used to generate electric power. 6. the bottom outlets are operate for (2 months) because the water level was less than the minimum water level for operating power station. and the results obtained by running (esohd) for the daily operation for ( two sequence drought months) (9-10/2009) are listed in (tables 13 and 14 ,respectively) ,it is found: 1. the maximum calculated storage was (776.55 million m 3 ) while the minimum storage was (426.50 million m 3 ) for which is more than the minimum storage of the reservoir (188 million m 3 ). 2. the maximum calculated water level is (119.73 m.a.s.l.) while the minimum water level was (115.83 m.a.s.l.) which is more than the minimum water level of the reservoir (112 m.a.s.l. ). 3. the maximum calculated release is (400.95m 3 /s) while the minimum calculated release was (350.12 m 3 /s) which are more than the minimum discharge of the river (70 m 3 /s). 4. power station was not operated because the water level was less than (118 m.a.s.l.) which is the minimum elevation of water can operate one turbine of the power station and the release was just from the bottom outlets. 5. the spillway has not operated for the same reason above. 6. the bottom outlets are operating for (all the two months) because the water level was less than the minimum water level for operating power station. for both monthly and daily operations it is found that the calculated water level was just (0.10 m) more than the measured water level which is calculated from the correct storage and release which mean that the building of the program is correct. 7. conclusions from the results obtained by running (esohd), the next conclusions are deduced: 1. the (esohd) gave results with a good agreement for the monthly and the daily operation with the real operation of haditha dam which mean that the building of the program is correct. 2. the program able the user to update the data that used for operating haditha dam by taking the new data from a [file]. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 11 3. for normal operation years the (esohd) program shall take the lower limit of the storage is the minimum operation storage and minimum operation water level (2300 million m 3 ) with water level (129.50 m.a.s.l.) while in drought years the (esohd) program shall take the lower limit of the storage is (188 million m 3 ) with water level (112 m.a.s.l.) which is the minimum storage and minimum water level of the reservoir. 4. for the (21 years adopted in the search) almost the years were drought years which means that the program satisfying the water requirements for more than a drought year which means it is dependable for operating the dam. there are many causes for the droughts in iraq in the last years one of them is the dams built on euphrates river in turkey and syria, the increasing in population in iraq which means increasing in water demands and at last the global increasing in heat temperature. 8. references abd-elhamid, h. f., javadi, a.a., negm, a.m. elalfi, a.e. and owais,t.m. (2011):" development of an expert system for maintenance and repair of masonry barrages ",intelligent computing in engineering – ice08 212. www./ state.awra.org/.../2012awra-ak_program_final. al-janabi, w. k. k. , ( 2004 ) : " preparation of decision support system for haditha dam system" , m.sc. thesis, college of engineering, university of baghdad. ali, a.a.,(1994) :"studying empty alrazaza lake",furat center, irrigation ministry, baghdad,(arbic). al-matlabie, a.h.,(1999): "the expert system for operation of the multi-purpose reservoir system of al-adheem dam", m.sc. thesis, university of baghdad. chow,v.t., (1959) :"open channel hydraulics ", mcgraw hill company, new york. emiroglu, m. e., (2008) :” influences on selection of the type of dam” , international journal of science & technology, volume 3, no 2, p.173-189. giarratano, j. and riley, g. (1962). “expert system principles and programming.” pws publishing company, a division of international thomson publishing inc. (g.s.d.r.),(general staff of dams and reservoirs),(2012):"data of haditha reservoir ", water resources ministry, iraq, not puplished. ishaq, m.b.,(1998):"optimum operation rules for tigris – euphrates system in iraq",ph.d. thesis, college of engineering, baghdad university. kamnev, n. m., sonichev, n. a., malyshev, n. a. ,(1984): "earth dam of the al-hadithah hydropower development on the euphrates river". power technology and engineering 17 (10): 530–33. doi:10.1007/bf01425184. kumara, s. and soyster, a. (1986): “an introduction to artificial intelligence.” industrial engineering. developing expert system for operating haditha dam 12 mohan, s. and arumugam, n. (1995): “hybrid expert system for operation of a small surface storage system”, modelling and management of sustainable basin-scale water resource systems (proceedings of a boulder symposium, july 1995), 1ahs publ, no. 231, p. 241-246. simonovics , s. p. (1990) :” issues in developing an expert system for flow measurement”, the hydrological basis for water resources management, iahs publ, no. 197, p. 335-343. swart, h. s. ,van rooyen, p. g. , mwaka, b. and ntuli, c. (2009) :” operating rules for dams with high evaporation losses”, international journal of science & technology, volume 4, no 3, p.150162. tospornsampan , j., kita, i. , ishii, m. , and kitamura, y. (2005):"optimization of a multiple reservoir system operation using a combination of genetic algorithm and discrete differential dynamic programming: a case study in mae klong system, thailand", paddy water environ (2005) 3: 29–38. www./isha.info/redbooks/a231.pdf. varas ,e.a. and chrismar,m.v. (1995): "expert system for the selection of methods to calculate design flood flows",hydrological sciences -journaldes sciences hydrologiques,4q,6, december. www.itia.ntua.gr/hsj/redbooks.g311.pdf table 1 the basic data of haditha reservoir ( g.s.d.r.( 2012)) storage in reservoir (m 3 *10 6 ) value reservoir water level (m.a.s.l.) value maximum(smax) 9850 maximum(wlmax) 150.2 minimum(smin) 188 minimum(wlmin) 112 designed operated (sd) 8200 designed operated (dwl) 147 normal operated(sn) 6591 normal operated(nwl) 143 minimum operated(sm) 2362 minimum operated(mwl) 129.5 table 2 the basic designed concepts of haditha dam structures and river (ali,a.a.,(1994)) property value maximum designed discharge of the river (m 3 /s) 4730 minimum designed discharge of the river (m 3 /s) 70 maximum designed discharge released from power station (m 3 /s) 2034 maximum designed discharge released from bottom outlets (m 3 /s) 4000 maximum designed discharge released from spillway (m 3 /s) 11000 * *this discharge will be at waterlevel (154 m.a.s.l.). http://www./isha.info/redbooks/a231.pdf http://www.itia.ntua.gr/hsj/redbooks.g311.pdf al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 13 table 3 the water demands downstream haditha dam (m 3 *10 6 ) (ali,a.a.,(1994)) the month irrigation , artificer , hygiene requirement environmental requirement total 10 1241.5 187.5 1429 11 859.8 187.5 1047.3 12 391.8 187.5 579.28 1 559.8 187.5 747.3 2 1034.6 187.5 1222.1 3 1526 187.5 1713.5 4 1969.9 187.5 2157.4 5 1846.6 187.5 2034.1 6 2489.8 187.5 2677.3 7 2569.5 187.5 2757 8 2122.4 187.5 2309.9 9 1241.9 187.5 1429.4 table 4 the average monthly perception and evaporation for haditha reservoir (from 1991 – 2011) the month perception ( mm ) evaporation (mm) 10 5.7 198 11 9.8 132 12 22.5 88 1 18.8 44 2 16.9 66 3 20.4 110 4 22.2 154 5 5.7 220 6 0 286 7 0 330 8 0 308 9 0 264 table 5 upper rule and lower rule curves for haditha dam (m 3 *10 6 ) the month upper rule lower rule 10 4811.4 2296.6 11 5300.2 2560.3 12 6051.1 3574.6 1 6781.4 4288.9 2 7036.6 4288.9 3 7430.6 4320.4 4 7520.1 4913.7 5 7930.8 5445.4 6 7520.1 4811.4 7 6656.0 3602.7 8 2734.0 5630.3 9 2426.2 5264.3 developing expert system for operating haditha dam 14 table 6 the measured inflow ( m 3 / s ) 9 8 7 6 5 4 3 2 1 12 11 10 inflow 345 434 410 387 427 194 381 399 510 551 475 457 1991 221 247 280 343 293 296 351 552 496 547 277 274 1992 256 366 408 401 497 337 392 358 414 468 405 340 1993 733 517 418 356 334 458 442 626 486 527 427 432 1994 528 513 376 296 351 704 861 1235 1286 1232 1150 950 1995 663 753 696 502 815 1497 1411 1309 1169 920 1083 590 1996 493 586 809 771 732 1073 1127 1345 1056 903 873 750 1997 644 675 589 580 865 817 1443 1350 1132 1220 989 713 1998 303 258 262 310 370 429 623 945 1013 1045 832 698 1999 250 262 339 336 343 366 802 1187 934 751 611 355 2000 281 606 331 153 213 214 287 377 310 303 285 285 2001 287 273 335 303 229 299 216 391 616 613 247 238 2002 457 308 282 288 367 548 788 635 663 825 582 348 2003 650 569 349 554 1207 665 1789 1214 710 547 742 515 2004 339 525 495 465 358 493 665 859 925 903 700 648 2005 679 873 809 603 574 512 623 1331 934 537 731 625 2006 584 821 716 379 621 555 581 751 1173 958 643 382 2007 548 542 403 355 307 343 436 758 879 532 374 386 2008 305 288 310 293 263 225 259 278 310 402 312 296 2009 333 756 461 315 314 337 288 405 350 385 386 349 2010 455 551 475 457 475 312 423 576 592 493 446 282 2011 table 7 the measured water level ( m.a.s.l.) 9 8 7 6 5 4 3 2 1 12 11 10 w.l. 137.12 137.04 135.96 134.32 132.59 131.03 133.12 135.88 137.28 137.11 136.90 136.95 1991 143.08 143.55 143.99 144.36 144.35 144.09 143.82 142.64 140.41 137.55 136.23 136.90 1992 144.61 145.82 145.99 146.65 146.52 145.94 145.62 145.06 144.78 144.40 143.92 143.09 1993 144.22 144.14 144.89 145.87 146.49 146.36 146.09 145.90 145.34 145.11 144.63 144.22 1994 141.45 142.17 142.44 143.69 145.22 146.03 146.35 146.27 145.73 144.97 144.81 144.20 1995 139.82 141.98 144.04 146.28 147.00 147.11 147.27 145.28 143.61 143.49 142.33 141.42 1996 140.80 143.26 145.72 146.90 147.03 146.36 144.54 143.67 142.33 141.53 141.07 139.98 1997 138.71 141.38 143.85 146.18 147.27 147.06 146.55 145.52 143.95 142.35 140.27 139.25 1998 131.46 137.17 140.20 144.54 146.37 146.45 145.96 144.83 143.63 141.83 139.41 138.44 1999 142.15 140.63 142.34 143.77 144.61 144.80 144.55 141.26 135.99 132.31 128.45 128.55 2000 134.45 133.91 133.25 134.73 135.96 135.93 136.28 136.13 134.89 133.83 135.17 136.62 2001 137.81 139.09 140.14 140.29 140.20 139.55 139.74 139.29 135.92 131.20 129.83 132.60 2002 135.74 137.21 139.62 141.61 143.00 143.05 142.72 142.14 142.41 140.80 138.64 137.61 2003 143.70 144.15 145.25 146.72 146.90 146.38 146.17 143.51 140.60 139.48 138.01 136.45 2004 140.84 142.45 143.65 144.72 145.48 146.16 146.43 146.14 146.05 144.93 144.03 143.77 2005 144.70 145.53 145.88 146.68 146.51 146.59 146.27 146.02 143.44 141.79 141.38 139.81 2006 143.81 144.71 145.02 146.11 146.96 146.83 146.78 146.22 145.55 142.73 142.07 143.35 2007 135.29 136.52 138.51 140.31 141.39 142.22 143.27 142.32 139.89 138.99 140.21 142.30 2008 118.66 121.19 123.42 123.96 123.96 124.68 125.75 127.04 127.65 127.33 128.68 131.80 2009 131.69 130.56 128.83 129.22 129.13 127.94 127.04 126.23 122.40 119.12 116.46 116.47 2010 135.72 136.76 136.29 136.80 136.26 135.25 135.58 134.05 131.56 128.53 129.11 129.87 2011 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 15 table 8 the calculated water level (m.a.s.l.) 9 8 7 6 5 4 3 2 1 12 11 10 w.l. 137.12 137.04 135.96 134.32 132.59 131.03 133.06 135.88 137.28 137.06 136.90 136.80 1991 143.08 143.44 143.99 144.36 144.35 144.09 143.82 142.64 140.41 137.55 136.23 136.90 1992 144.55 145.67 145.99 146.65 146.52 145.94 145.62 145.06 144.78 144.40 143.92 143.09 1993 144.02 144.14 144.89 145.87 146.49 146.36 146.00 145.90 145.34 145.11 144.63 144.17 1994 141.45 142.17 142.44 143.69 145.22 146.03 146.35 146.27 145.58 144.97 144.81 144.20 1995 139.82 141.98 144.04 146.28 147.00 147.04 147.27 145.28 143.61 143.49 142.33 141.31 1996 140.80 143.26 145.72 146.90 147.03 146.36 144.54 143.67 142.33 141.53 141.07 139.98 1997 138.62 141.30 143.85 146.18 147.22 147.06 146.55 145.52 143.80 142.35 140.27 139.05 1998 131.46 137.17 140.20 144.54 146.21 146.45 145.96 144.83 143.63 141.83 139.41 138.44 1999 142.15 140.63 142.34 143.77 144.61 144.80 144.55 141.26 135.99 132.31 128.45 128.55 2000 134.45 133.91 133.25 134.73 135.96 135.93 136.28 136.13 134.89 133.83 135.17 136.62 2001 137.81 139.09 140.14 140.29 140.20 139.55 139.74 139.29 135.92 131.20 129.83 132.60 2002 135.74 137.21 139.62 141.61 143.00 143.05 142.72 142.14 142.41 140.80 138.64 137.61 2003 143.70 144.15 145.25 146.72 146.72 146.38 146.07 143.51 140.70 139.48 138.01 136.59 2004 140.84 142.45 143.65 144.72 145.48 146.16 146.43 146.14 146.05 144.93 144.03 143.77 2005 144.70 145.53 145.88 146.68 146.51 146.59 146.27 146.02 143.44 141.79 141.38 139.91 2006 143.81 144.71 145.02 146.11 146.96 146.83 146.63 146.22 145.55 142.73 142.07 143.35 2007 135.95 136.52 138.41 140.31 141.39 142.22 143.12 142.39 139.89 138.99 140.04 142.20 2008 118.66 121.19 123.42 123.96 123.96 124.68 125.75 127.04 127.65 127.33 128.68 131.80 2009 131.69 130.56 128.83 129.22 129.13 127.94 127.04 126.23 122.40 119.12 116.46 116.47 2010 135.95 136.76 136.29 136.80 136.26 135.25 135.58 134.05 131.56 128.53 129.11 129.87 2011 table 9 the calculated release (m 3 / s) 9 8 7 6 5 4 3 2 1 12 11 10 release 342 304 225 205 188 198 217 792 926 446.4 439.0 351 1991 312 308 367 374 260 233 253 230 204 219 318 341 1992 408 432 437 406 347 264 218 223 329 431 279 291 1993 572 440 464 485 304 325 346 470 399 403 325 347 1994 564 474 339 523 504 679 817 1163 1100 1063 893 688 1995 732 988 863 715 694 1519 1088 845 818 839 715 480 1996 705 918 991 722 593 643 777 1044 783 790 689 521 1997 746 1019 867 830 722 682 1123 930 787 783 684 734 1998 606 654 794 813 366 342 429 574 673 697 441 576 1999 441 446 452 444 332 386 423 370 232 380 405 399 2000 327 360 330 291 212 160 296 256 173 219 460 417 2001 289.6 386 326 223 130 160.6 233 184.6 134.2 211 387.4 411 2002 319.7 469.9 457.2 446.3 367.4 337.6 514.7 542.9 558.8 236.5 290 225 2003 536.9 538.1 511.8 587.0 633.3 577.2 1127.4 344.0 272.5 329.8 292.2 258.3 2004 471.9 598.0 628.6 486.1 406.5 531.5 571.1 654.0 705.6 537.3 471.6 500.6 2005 631.1 685.4 664.2 556.7 399.0 400.5 505.8 881.8 364.6 397.7 400 400.5 2006 683.7 700.5 633.5 555.2 568.7 438.2 443.3 665.9 639.2 433.2 609.1 652.7 2007 649.7 612.4 600.4 459.1 400.2 353.0 419.0 408.8 415.8 527 609.1 614.6 2008 398.3 400 372.4 278.3 205 250 276 300 300 371.4 413.7 546.1 2009 488.2 436.8 362.9 282.5 200 200 202.1 300 211 240.3 360.3 369.7 2010 561.3 446.4 439.0 351 255.9 292.57 338 241.3 384.1 399.9 515.9 468.0 2011 developing expert system for operating haditha dam 16 table 10 the calculated storage (million m 3 ) 9 8 7 6 5 4 3 2 1 12 11 10 storage 4326.4 4302.6 3968.2 3496.1 3037.9 2659.4 3158.6 3945.1 4376.6 4290.6 4268.7 4226.0 1991 6481.8 6630.9 6863.2 7019.1 7014.4 6902.6 6789.3 6304.1 5447.4 4463.9 4049.0 4256.9 1992 7101.4 7594.1 7740.9 8048.4 7988.4 7716.4 7571.7 7324.0 7199.5 7038.3 6830.4 6487.5 1993 6875.0 6925.7 7249.3 7686.5 7972.5 7911.3 7744.3 7699.5 7449.5 7346.2 7134.3 6937.4 1994 5839.3 6119.2 6224.5 6736.1 7396.2 7758.3 7906.6 7869.8 7554.6 7284.0 7214.2 6950.5 1995 5234.3 6041.9 6881.7 7876.0 8210.2 8229.3 8339.8 7421.3 6700.8 6652.2 6181.2 5784.1 1996 5593.8 6556.1 7618.5 8164.3 8225.3 7913.5 7096.5 6727.1 6181.5 5868.3 5692.5 5291.7 1997 4818.4 5781.3 6802.5 7828.0 8314.5 8240.7 8001.0 7527.5 6781.3 6188.1 5396.6 4966.5 1998 2760.5 4342.2 5372.4 7097.6 7843.8 7951.7 7728.8 7223.4 6709.4 5984.7 5089.6 4757.9 1999 6110.9 5529.3 6185.6 6770.4 7127.1 7209.4 7099.4 5764.3 3977.2 2966.6 2100.1 2121.5 2000 3533.7 3383.6 3207.5 3611.3 3969.0 3960.0 4065.4 4021.6 3655.7 3361.7 3735.3 4169.9 2001 4548.4 4978.8 5350.4 5404.9 5372.2 5139.5 5206.9 5049.1 3955.8 2699.2 2388.7 3040.6 2002 3903.5 4355.5 5165.0 5898.9 6448.1 6471.2 6335.9 6103.8 6213.5 5592.8 4824.7 4483.4 2003 6738.8 6930.4 7406.5 8081.6 8080.0 7919.1 7776.2 6661.7 5555.0 5113.1 4615.3 4161.6 2004 5608.2 6228.3 6719.6 7176.8 7512.5 7819.9 7945.6 7810.3 7768.8 7267.2 6879.8 6769.5 2005 7165.0 7534.2 7691.4 8060.6 7980.1 8018.0 7870.5 7753.4 6630.1 5970.3 5811.2 5265.9 2006 6785.4 7168.7 7305.3 7794.3 8191.2 8129.6 8038.3 7844.8 7541.6 6342.3 6079.5 6593.9 2007 3772.1 4140.3 4748.6 5411.6 5814.8 6135.3 6497.2 6203.8 5260.9 4944.4 5312.9 6128.0 2008 666.9 942.8 1237.9 1317.2 1316.5 1427.4 1601.6 1829.7 1943.8 1884.0 2146.0 2843.0 2009 2816.0 2550.4 2176.9 2257.6 2240.0 1999.7 1828.7 1684.6 1096.6 713.0 474.0 475.1 2010 3896.6 4212.6 4068.7 4226.0 4060.2 3760.5 3854.9 3421.7 2784.3 2116.9 2235.5 2397.0 2011 table 11 the calculated power produced (mw) 9 8 7 6 5 4 3 2 1 12 11 10 power 97.7 87.0 62.8 54.3 47.1 46.8 55.0 207.4 250.7 64.2 88.5 96.7 1991 105.8 105.5 126.8 130.3 91.5 81.7 87.9 77.7 65.1 149.7 97.0 98.9 1992 142.5 154.8 157.8 149.3 127.9 96.6 79.4 80.1 116.3 142.8 114.5 120.6 1993 194.4 151.6 162.7 173.9 112.3 119.5 125.9 168.9 142.2 356.3 301.9 232.6 1994 179.0 154.7 112.8 176.9 177.6 240.7 288.9 400.3 373.6 275.1 229.4 152.9 1995 218.3 306.9 286.6 254.4 251.7 520.4 386.1 290.2 269.5 246.3 213.9 159.2 1996 216.9 297.2 340.5 260.7 216.9 230.5 263.2 338.5 249.8 250.0 207.6 213.9 1997 214.3 309.7 286.4 292.0 262.7 247.9 390.4 319.3 261.2 220.9 133.5 167.3 1998 138.1 181.2 238.2 274.6 133.6 125.8 154.9 199.1 224.5 91.9 83.9 83.1 1999 144.2 139.8 148.4 151.5 116.9 135.9 147.5 118.9 64.7 57.0 121.8 116.3 2000 85.8 92.4 83.1 77.4 59.2 44.9 82.7 71.6 46.9 50.1 85.2 100.1 2001 84.9 116.4 101.9 70.7 41.5 50.2 72.7 57.2 37.8 76.0 87.2 66.0 2002 87.6 132.8 139.1 143.8 123.7 114.1 169.8 175.9 182.2 101.2 86.2 73.2 2003 181.4 184.0 180.3 213.2 229.2 208.0 387.0 117.6 87.0 187.4 161.7 170.0 2004 148.4 194.4 210.5 169.4 145.3 191.2 206.2 233.0 249.8 129.3 128.6 123.5 2005 217.2 239.9 234.9 202.5 146.3 147.1 182.9 307.8 124.2 144.0 195.9 216.4 2006 228.9 239.8 219.7 199.1 208.0 161.4 162.5 237.4 224.6 156.3 184.9 198.2 2007 169.3 166.8 173.8 142.4 128.7 116.6 140.9 134.9 128.0 73.6 86.4 127.0 2008 48.1 57.3 61.0 47.7 35.6 44.6 51.7 59.4 61.0 0.00 0.00 0.00 2009 113.9 98.2 76.8 61.5 43.9 41.8 40.6 57.2 33.7 83.2 108.2 101.9 2010 149.7 124.7 120.9 99.1 71.8 79.2 92.0 63.1 90.3 115.5 121.2 129.6 2011 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 17 table 12 the calculated dswl (m.a.s.l.) 9 8 7 6 5 4 3 2 1 12 11 10 dswl 101.78 101.64 101.37 101.29 101.23 101.27 101.34 103.22 103.61 101.34 101.69 101.77 1991 101.67 101.66 101.86 101.89 101.49 101.39 101.47 101.38 101.29 102.08 101.56 101.60 1992 102.00 102.08 102.10 101.99 101.79 101.50 101.34 101.36 101.73 101.98 101.72 101.79 1993 102.54 102.11 102.19 102.26 101.64 101.72 101.79 102.21 101.97 104.01 103.52 102.90 1994 102.51 102.22 101.77 102.38 102.32 102.87 103.29 104.29 104.11 103.36 102.98 102.24 1995 103.04 103.79 103.43 102.98 102.92 105.23 104.08 103.38 103.30 103.21 102.90 102.37 1996 102.95 103.59 103.80 103.01 102.60 102.76 103.17 103.95 103.19 103.19 102.89 103.04 1997 103.08 103.88 103.44 103.33 103.01 102.88 104.17 103.63 103.20 102.93 102.11 102.55 1998 102.65 102.80 103.22 103.28 101.86 101.78 102.07 102.54 102.85 101.91 101.99 101.97 1999 102.11 102.13 102.15 102.12 101.74 101.93 102.05 101.87 101.39 101.34 102.17 102.03 2000 101.72 101.84 101.73 101.60 101.32 101.13 101.62 101.48 101.18 101.31 101.93 102.01 2001 101.59 101.93 101.72 101.36 101.02 101.13 101.39 101.22 101.03 101.41 101.60 101.37 2002 101.70 102.21 102.16 102.13 101.86 101.76 102.35 102.44 102.49 101.73 101.60 101.48 2003 102.42 102.43 102.34 102.58 102.73 102.55 104.19 101.78 101.53 102.43 102.21 102.31 2004 102.21 102.62 102.72 102.26 102.00 102.41 102.53 102.80 102.96 101.97 101.97 101.97 2005 102.72 102.89 102.83 102.49 101.97 101.97 102.32 103.49 101.85 102.08 102.65 102.79 2006 102.89 102.94 102.73 102.48 102.53 102.10 102.12 102.83 102.75 102.39 102.65 102.67 2007 102.78 102.67 102.63 102.17 101.97 101.81 102.04 102.00 102.03 101.88 102.02 102.45 2008 101.97 101.97 101.88 101.55 101.29 101.45 101.55 101.63 101.63 101.42 101.84 101.87 2009 102.27 102.10 101.85 101.57 101.28 101.28 101.28 101.63 101.31 101.97 102.36 102.20 2010 102.50 102.13 102.10 101.81 101.48 101.60 101.76 101.42 101.92 102.10 102.30 102.35 2011 table 13 the daily operation for (month 9/2009) storage (million m3) relaese (m3/s) water elevation (m.a.s.l.) 2009/9 776.55 401.22 119.73 1 760.60 400.71 119.58 2 746.94 400.28 119.45 3 738.61 400.01 119.37 4 731.38 399.77 119.3 5 721.11 399.44 119.2 6 715.00 399.24 119.14 7 711.96 399.14 119.11 8 708.92 399.04 119.08 9 707.91 399.00 119.07 10 710.94 399.10 119.1 11 709.93 399.07 119.09 12 704.88 398.90 119.04 13 698.86 398.70 118.98 14 693.86 398.53 118.93 15 683.93 398.20 118.83 16 665.32 397.56 118.64 17 649.90 397.03 118.48 18 638.48 396.62 118.36 19 developing expert system for operating haditha dam 18 626.26 396.19 118.23 20 611.42 395.65 118.07 21 602.26 395.32 117.97 22 594.08 395.02 117.88 23 582.41 394.58 117.75 24 572.64 394.21 117.64 25 562.97 393.84 117.53 26 553.41 393.47 117.42 27 542.25 393.04 117.29 28 525.35 392.37 117.09 29 520.34 392.17 117.03 30 table 14 the daily operation for (month 10/2009) storage (million m3) release (m3/s) water elevation (m.a.s.l.) 2009/10 506.33 400.95 116.86 1 491.75 400.33 116.68 2 479.81 399.81 116.53 3 466.50 399.23 116.36 4 456.48 398.79 116.23 5 445.09 398.27 116.08 6 434.62 397.79 115.94 7 426.50 397.41 115.83 8 427.24 397.45 115.84 9 431.65 397.65 115.9 10 435.36 397.82 115.95 11 437.59 397.93 115.98 12 438.34 367.20 115.99 13 444.33 362.40 116.07 14 451.14 358.21 116.16 15 458.78 355.55 116.26 16 467.27 352.00 116.37 17 476.66 351.21 116.49 18 484.56 350.95 116.59 19 488.55 350.72 116.64 20 490.15 350.52 116.66 21 490.15 350.15 116.66 22 491.75 350.12 116.68 23 490.95 350.10 116.67 24 489.35 350.21 116.65 25 485.36 350.46 116.6 26 481.39 350.79 116.55 27 478.23 350.42 116.51 28 477.44 350.89 116.5 29 475.87 350.99 116.48 30 474.30 350.69 116.46 31 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 19 figure 1 the upper and the lower rule curve by ( ali a.a. , (1994) ) figure 2 the relationship between storage, surface area and water level of the reservoir by (ishaq, (1998)) developing expert system for operating haditha dam 21 figure 3 curves represented the relation between gate opening and the discharge for the bottom outlets for different water level by (g.s.d.r. (2012)) figure 4 analysis of previous figure . al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 21 figure 5 the relation between cd and ratio of (open gate/pressure head)by (chow,(1959) figure 6 the main menu of (esohd) for monthly option developing expert system for operating haditha dam 22 figure 7 the welcome window of monthly operation figure 8 the results for monthly operating al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 23 figure 9 the details for operating year (2009) figure 10 the main menu with daily operating option developing expert system for operating haditha dam 24 figure 11 the welcome window of daily operation figure 12 the result for operating two month (9-10/2009) al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 25 figure13 the details for daily operating al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 347 comparison between simulated and calculated power of the solar chimney with black concrete base using ansys program ali k. al-abadi ahmed f. kridi ghassan fadhil m. hussain university of baghdad university of baghdad university of kufa al-khwarizmi college of engineering al-khwarizmi college of engineering college of engineering abstract a solar chimney has been analyzed by solving its governing equations and compare with the simulated results. the solar absorbent of the chimney is selected as a black painted concrete, which is useful as an energy saver at night. the numerical simulation using ansys, based on solving the governing equations with suitable assumptions and boundary conditions for many variables such as the collector area, the chimney height, the ambient temperature, and the exit area of the chimney. the results shows that the chimney height and base area are very important parameters for improving the gained power, and it is also important to choose the region with suitable mean ambient temperature. and economically there are limitations to collector and chimney sizes to get suitable profit output power and any increment in system size becomes a small percentage increment in profit output power. the results compared with some experimental data from other results researchers and there is a good agreement between simulated and calculated results. keywords: solar chimney, concrete base, solar collector, ansys, simulation ة سوداء بأستخدام كونكریتیقاعدةذاتمقارنة بین القدرة النظریة والمحسوبة لمدخنة شمسیة ansysبرنامج غسان فاضل محمد حسیندي یعلي خضر العبادي أحمد فؤاد كر جامعة بغداد جامعة الكوفةجامعة بغداد كلیة الھندسةسة الخوارزمي ھندالھندسة الخوارزمي كلیة الكلیة الخالصة اللوح الماص للمدخنة الشمسیة تم إن .ئج مع نتائج المحاكاةتم تحلیل المدخنة الشمسیة عن طریق حل المعادالت الحاكمة ومقارنة النتا ansysإن المحاكاة العددیة باستخدام برنامج . اختیاره من الكونكریت المطلي باللون االسود والذي یعتبر مفیدا لخزن الحرارة لیال متغیرات مثل مساحة المجمع ارتفاع المدخنة تم بناءه على حل المعادالت الحاكمة مع الفرضیات والشروط الحدیة المناسبة لعدة11.0 أظھرت النتائج أن ارتفاع المدخنة ومساحة المجمع ھي عوامل مھمة جدا لتحسین . ودرجة حرارة المحیط و مساحة مخرج المدخنة مدخنة والمجمع م الھناك محددات اقتصادیة لحجوان.القدرة الناتجة، وكذلك من المھم اختیار المنطقة بمعدل درجة حرارة محیط مناسبة ناظرت النتائج في .القدرة الخارجة المفیدةفيزیادةنسبة الزیادة في الحجم یقلل من أي الشمسي للحصول على قدرة خارجة مناسبة وان . جیدا بین نتائج الحسابات والمحاكاة الباحثین آخرین وان ھناك تقارببعض النتائج التجریبیة ھذا البحث مع nomenclature al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 348 latin symbols symbol description units . m working air mass flow rate kg/sec ao exit chimney area m 2 cp specific heat at constant pressure j/kg.k h chimney height m h enthalpy j/kg ha convective heat transfer coefficient between the absorber and the air flow inside the collector. w/m2.k hc convective heat transfer coefficient between the cover and the air flow inside the collector. w/m2.k hrc-a radiation heat transfer coefficient between the cover and the absorber . w/m2.k it total energy projected by the solar radiation on a surface w/m 2 k thermal conductivity of working fluid w/m. oc p air pressure n/m2 q rate of heat transfer watt q energy transfer by the working fluid watt r specific gas constant j/kg.k s absorbed solar radiation w/m2 sa solar radiation absorbed by the absorber. w/m 2 sc solar radiation absorbed by the transparency cove. w/m 2 t∞ temperature of the air out of the collector oc tf air flow temperature oc ti mean air temperature at inlet to the chimney tower. oc ue overall heat transfer coefficient the absorber to the earth through the isolator. w/m2.k ut overall heat loss coefficient from cover and the air out the collector plus the radiation heat transfer. w/m2.k v air velocity m/sec vo exit velocity m/sec xr body forces in r-direction n δt collector air temperature rise =(ti –ta) oc greek symbols symbol description units µ air dynamic viscosity n.s/ m2 η efficiency ρ air density kg/ m3 τα visual efficiency τ transmission coefficient α absorption coefficient φ loss energy watt σ stefanboltzman constant=5.669×10-8. w/m2k4 εg ground emittance -----εc canopy film emittance -----al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 349 introduction the concept of solar chimney power technology was first conceived in 1931 by a german author, hanns gunther, and has been proven with the successful operation of a pilot plant constructed in manzanares, spain in the early 1980s by professor schlaich with the support of both the german government and a spanish electric company (schlaich,1995). (haff,1984) the first one to describe the principles and construction of the pilot plant in manzanares, it had been concluded that economical power generation will be possible with large scale plants design for up to 400mw. also, find a number of fundamental differences between the solar chimneys and the other power generation installations. as opposed systems, they don’t require direct radiation, but still generate current when the sky is overcast and the radiation is 100% diffused. on the other hand, atmospheric infrared radiation plays an important role in the overall energy balance of solar chimneys, while in concentrating systems or in the case of photovoltaic generators the infrared thermal radiation has only a very slight influence or none at all. the authors finally concluded that a solar chimney with an installed capacity of over approximately 50mw could generate electricity economically. (haff,1983) presented the preliminary test results from the manzanares pilot plant. by depending on the test results and the operation experience gained throughout the period of the test, he has found that the agreement extent between the physical model and the measurements was good. the most important result so far is that with ground like that in manzanares, with modified plant dimensions, the daily peak could theoretically be increased by approximately 8% without increasing the cost of the plant. and he found that at the very first attempt the simple principle, the reliability and above all the favorable costpower relation for large-scale plants were confirmed on scale, which may be called unique among known solar chimney power plants. (jackobs,1984) studied the theoretical analysis of the solar-driven natural convection energy conversion system. they presented a theoretical study of solar-powered natural convection tower (chimney) performance. both heated and cooled towers were analyzed. the later used evaporating water as the cooling mechanism. the results, which were applicable to any open cycle configuration, showed that the ideal conversion efficiencies of both heated cooled natural convection towers were linear functions of height. the performance of heated tower in an adiabatic atmosphere had been found to approach the ideally carnot efficiency limit of approximately 3.4%/km. the ideal limit to cooled water performance when including water pumping requirements was approximately 2.75%/km. (al-heaty,2002) developed a general computer model to predict the performance of solar chimney plants. the analysis was based on the nonlinear numerical solution, using finite element method, for the system of governing partial differential equations (continuity, momentum, and the energy equations) of the conventional heat transfer fields through the plant collector and chimney tower passages. it was resulted the finite element method gives accurate results, nearly to the exact solution in the analysis of solar chimney power plant. (gan,1998) study the performance of a glazed solar chimney for heat recovery in naturally-ventilated buildings was investigated using the cfd technique, its validated against experimental data from the literature and good agreement between the prediction and measurement was achieved. the predicted ventilation rate increased with the chimney wall temperature. the effects of solar heat gain and glazing type were investigated. it was shown that in order to maximize the ventilation rate in a cold winter, double or even triple glazing should be used. (toufik chergui,2010) presented the related to heat transfer and airflow modeling analysis in solar chimneys, according to some dominant parameters. a typical case of application is given in this study. it consists in analyzing a natural laminar convective heat transfer problem taking place in a chimney. heat transfer and fluid dynamic aspects of the airflow, through an axis symmetric system in a al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 350 dimensionless form, with well defined boundary conditions is thus examined. results are related to the temperature distribution and the velocity field in the chimney and in the collector, determined by solving the energy equation, and the navier–stokes equations, using finite volume method. (mullett,1987) carried out an analysis for solar chimney aimed particularly at deriving overall efficiency and significant performance data. numerical values were consistent with the available information on the 200m solar chimneys at manzanares, spain, and project designs. it was found that the overall efficiency was directly related to the height of the chimney and was shown to be 1% for a height of 1000m and it was concluded that the solar chimney was essentially a large-scale power generator. (reheault,1988) studied the problem of steady laminar flow developing free convection in a vertical channel formed by two parallel plates of dissimilar non-uniform temperatures by using a finite difference method to solve the governing equations. the results were reduced in a non-dimensional form and correlations were derived for the case of air, which can be used in solar chimney design. (koonsrisuk,2009) shows that the achievement of complete dynamic similarity between a prototype and its models imposed the use of different solar heat fluxes between them. it is difficult to conduct an experiment by using dissimilar heat fluxes with different physical models. therefore, this study aimed to maintain dynamic similarity for a prototype and its models while using the same solar heat flux. the study showed that, to achieve the same-heat-flux condition, the roof radius between the prototype and its scaled models must be dissimilar, while all other remaining dimensions of the models are still similar to those of the prototype. (koonsrisuk,2010) they analyzed to increase the power production over the area occupied by the plant. the ratio height/radius, maximum mass flow rate and maximum power under the constraints of a fixed area and volume are determined. they found that the power generated per unit of land area is proportional to the length scale of the power plant. the analysis is validated by a detailed mathematical model. pressure losses are reported in terms of the dimensionless length scale of the system. they indicate that the pressure drop at the collector inlet and at the transition section between the collector and chimney are negligible. (maad,1992) analyzed numerically the natural convection flow between two heated vertical plates to design and realize solar chimney of the greatest efficiency, by considering the variation of the fluid properties with temperature and the pressure drop due to the flow acceleration at the channel entrance. they solved the equations of the momentum, continuity and energy by a finite difference method with an experimental study to validate the theoretical analysis. grid generated turbulence was used to improve the heat transfer in the channel. it was seen that the temperature in the middle of the channel was high and could reach 50% of the wall temperature. the hydrodynamic and thermal field becomes very unstable and the average nusselt number increased according to the quality of grid arrangements. (zhou,2006) in china a simulation study was carried out to investigate the performance of the power generating system based on a developed mathematical model. the simulated power outputs in steady state were obtained for different global solar radiation intensity, collector area and chimney height. by inter comparison, it is found that the simulated power outputs are basically in agreement with the results calculated with the measurements, which validates the mathematical model of the solar chimney thermal power generating system. then in experimental solar chimney power setup consisted of a 5mradius air collector and 8 m-height chimney has been built. the temperature distribution in the solar chimney power setup was measured. temperature difference between the collector outlet and the ambient usually can reach 24.1°c, which generates the driving force of airflow in the setup. this is the greenhouse effect produced in the solar collector. it is found that air temperature inversion appears in the latter chimney after sunrise both on a cool day and a warm day (zhou,2007). its mainly focused on structure models, efficiency of energy conversion and other related problems for solar chimney power technology. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 351 (dai ,2003) study solar power plant chimney, and the influence of chimney height, diameter of the solar collector, ambient temperature, solar irradiance and the efficiency of wind turbine, in which the height and diameter of the chimney are 200 m and 10 m, respectively, and the diameter of the solar collector cover is 500 m, and found its able to produce 110~190 kw electric power on a monthly average all year. the present study focused on studying many variable effects the performance of a domestic solar chimney such as the chimney height and the chimney rectangular base area and the ambient temperature. and the simulation compared with the case study of (dai ,2003). a detailed analysis of the measured temperature fields for solar chimney power systems had been reported. geometry description the solar chimney studied in the present work is shown in (figure1), which consists of vertical chimney with height (h) and width (w), with a turbine supported on top of guide cone which placed on the center of the absorbed plate (p), the absorbed plate with the covering transparent material and the down isolator considered as a solar collector with area (ac). air flow enters from collector sides and rises as it heated by the absorber to the exits opining of the chimney upper end (figure 1) solar chimney mathematical calculations: the governing equations which are used for the analysis the collector based on the energy balance to predict the performance of the solar chimney thermal power generating equipment for suitable and applicable assumptions: qu=qa-ql (1) where qu is the useful energy (the energy transferred to the air flow by convection), qa is the absorbed energy and ql is the energy lost (by convection and radiation) for general collector (duffie,1991): qa=sa.ac (2) s=it .(τα) (3) ql=ue ac (ta-t∞) (4) then qu=(τα) it ac –ue ac (ta-t∞) (5) and for solar chimney collector (where the air flow in and out) shows in (figure 2): solar radiation chimney outlet area (ao) chimney height h(m) turbine transparent cover(c) a solar collectorair flow in(i) absorber plate(a) isolator guide cone collector area (ac) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 352 (figure 2) collector energy balance. 1the transparence cover (c) energy balance equation (duffie,1991): sc + hrc-a (ta-tc) + hc (tc-tf) = ut(tc-t∞) (6) 2the absorber (a) energy balance equation: sa=ha(ta-tf)+hrc-a(ta-tc)+ue(ta-t∞) (7) hr,c-a is the radiation coefficient from the ground to the canopy (holman,1989):    111 2 1 22 ,              cg cgcg acr tttt h   (8) 3the airflow (f) energy balance equation: qu=ha ac (ta-tf)hc ac (tc-tf) (9) tf=(t∞/4)+(3to/4) (10) )t-(tcm 4 3 =)t-(tcm=q fp . op . u  (11) m=ρaovo (12) due to (schlaich1995):  tttghv oo /)(2 (13) by applying continuity equation between the inlet (i) and the outlet (o): vi= vo ao ρo/ai ρi (14) the collector efficiency, :(kays,1966) which represents an indicator to its performance, given by al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 353 tc p c ir tmc 2 .     (15) and the output power (zhou,2006) and (zhou,2007) is: po=0.33 η ρaovo3 (16) numerical simulation: the heat transfer and flow rate of ambient air when flowing freely from solar collector perimeter, under the collector canopy and over the absorber, towards the chimney tower inlet, is mainly governed by partial non linear differential equations, representing the conservation principals of mass, momentum, and energy; and can be written as; (yaun ,1967): continuity equation:       0 1             r v z vv rr v t rzr     (17) where vr, vθ, vz are the air velocity components in r, θ and z-directions respectively. momentum equation:                                                                               r vv rr v rr v z v z r v r vv rr q r v rr p xr r v dt dv rrzr rrr          12 11 . 3 2 2 2 (18) where r v z vv r v rr v q rzzrr               1 . . (19) energy equation: dt dp dt dh z t k z t k rr t kr rr                                2 11 (20) where h=cp.t & p=ρrt                                                                            2 2 22222 . 3 1 2 1 1 2 11 2 11 2 q r v z v vv r v rr v r v z v r vv rr v zr z zrzrr    (21) and z v r v r v tdt d zr               (22) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 354 assumptions: the following assumptions are considered: 1. the system performance is steady. 2. the problem of convectional heat transfer in the collector is that of constant wall temperature. 3. the working air thermal conductivity, k, and the coefficient of viscosity, μ, are constants. 4. the working air behaves as an ideal gas. 5. for the flow through the collector passage and at each (r), the pressure is constant in the vertical direction, that is to say 0   z p . 6. the flow through the collector has complete symmetry with the θ direction, that is to say,   =0. 7. the main direction of flow in the collector is the (r) direction, no flow in the z and θ directions (vz, v  =0). 8. the airflow varies inside the chimney tower with z and r-directions, and it has no variation in the θ direction, i.e. .0     9. the air inlet to the chimney collector from the down sides and flows out from the chimney top opening end without friction or leakage. 10. the thermal effect causing the buoyancy force is considered, and wind-induced natural ventilation in the ambient is neglected. 11. the temperature of the roof under the heat insulator bed is equal to that of the ambient t∞. boundary conditions: the following boundary conditions are considered: 1. the velocities components in x and y directions are set to zero at the chimney walls and the absorbed plate. 2. the pressure at the outlet end of the chimney is atmospheric pressure. 3. the temperature of the airflow enter to the collector sides is at the same ambient temperature t∞. 4. the temperature difference between the ambient temp t∞ and the absorber temp ta is about 24.1oc (zhou,2007) which generate the driving force of airflow in the setup. 5. the inlet flow velocity components in x-axis are (vi) and in y-axis is (0). 6. properties (pressure, temperature and density) at the inlet assumed at standard atmospheric. simulation procedure: by using ansys for numerical simulating the chimney, assuming axial summitry 2-d, and due to symmetry only half of the chimney was solved, and below the procedure of the simulation: ansys commands process screen plot al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 355 preprocesser modeling, create, (keypoints, lines and area) meshing, size cntrls, mesh drawing the model, keypoints, lines and areas generation for the section of the axiymmetrical chimney meshing the domain ansys commands process screen plot flotran set up fluid properties loads, apply, fluid/ cfd. setup the flow properties applying loads (boundary conditions) velocity, walls no slip condition, pressure. solution run flotran close starting the iteration till the convergence occurs al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 356 postprocessor plot results, counter plot, nodal solution vsum pressure plotting the resulting velocities and pressure distribution within the chimney results and discussion: a comparison between results got from simulation and that got from solving the governing equations shown in (figure 3), results shows that the output power gained by the power generating systems increases with the increment of chimney height (h) and also, with the increment of collector area (ac), the chimney height taken from 1 to 4 m, which is suitable height for domestic houses roofs, while the collector area taken from 1 to 16 m2, as rectangular area. the comparison between simulation and calculation results shows a good agreement about 5% in average, the small difference between simulated and calculated results is due to the assumption for the simulation like assuming the inlet velocity only in x-dir and the outlet is only in y-dir and the flow is one-dimensional at inlet and outlet and no heat loss due to friction, and the different which is not exceed 7% at chimney height of 4 m, and that at chimney height 1 m is about 2%, because with the increment of chimney height a larger force introduced that driving the turbine which is produced by more convection of heated air. the ambient temperature used for measuring the results in (figure 3) was chosen as 25oc, which is convenient as average temperature for the selected regions. (figure 4), shows the variation of the output power with the variation of chimney height and different ambient temperature of 10oc, 20oc, 30oc and 40oc, it is clear that the gained power increases with the increment of the ambient temperature, that because a high ambient temperature produce a high absorber temperature (ta), which cause more heated air that forced the turbine blades to rotate faster. the different between calculated and simulated output power for all ambient temperatures for different collector height is clear in (figure 5), and that different decreases as the ambient temperature increase, that because with small value of t∞ cannot heated the absorber well in order to provide a force enough for driving the turbine, or the low ambient temperature cannot usually produce enough driving force because part of the heat energy is absorbed and stored by the concrete absorber, that is appear in calculation measurement while in simulation it always consider that the convection force available and can produce even few power. the influence of outlet area of the chimney on the output power of the solar chimney at different chimney heights was shown in (figure 6), where with the increasing of the exit chimney area ao the al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 357 outlet power will decrease, that’s due to decrement of outlet velocity caused by increasing the exit chimney area ao (from continuity equation), and with the increment of chimney height the effect of the exit chimney area ao decreasing due to the larger power generated due to larger force introduced. both calculation and simulation done for collector area of 16 m2, to show the effect of the outlet area clearly due to maximum power gained with this area as in (figure 3). (figure 7), shows the power gained from the chimney by calculation and simulation for variations of collector area for different values (1,3,9,16) m2 and the chimney height for different values (1,2,3,4) m, it indicates that the larger the collector size and the higher the chimney height, the greater will be the power production of the solar chimney power plant. in (figure 8), the comparison between the simulation results with the experimental results got from (dai ,2003) was shown. the effect of solar chimney height and diameter of collector on the power generation appears for each case, and there is a good agreement between them. (figure 9) shows the effect of the ambient temperatures and solar chimney heights difference on the power gained by the chimney when the collector area is (ao =0.5 m2). when t∞=30oc. it can shown as the chimney height increase, (for certain collector area), the output power increase too. and the output power increase, (for certain chimney height), as the collector area increase too. the value of output power increase as the ambient temperature increase from the values 10oc to 40 oc . (figure 10) shows the effect of the variation of outlet area on the power gained by the chimney with different solar chimney heights and collector areas for (t∞=25 oc). it can shown as the chimney height increase, (for certain collector area), the output power increase too. and the output power increase, (for certain chimney height), as the collector area increase too. the value of output power increase as the chimney exit area reduced from 0.7 m2 to 0.2 m2. its demonstrated that the production of chimney power increases nonlinearly with the increase of collector area and the chimney height, it increases rapidly when the sizes of collector and the chimney are small, but the percentage growth in chimney power is reduced with an increase in their sizes as shown in (figure 11) so any increase in sizes will be useless as economically cost. conclusions 1. the simulated results showed good agreement with calculated results. 2. the simulation convenient to predict the performance of the solar chimney and that can save the cost of the experimental procedures. 3. it is concluded that the mathematical model can predict the performance of the chimney equipment well, and this approach is also applicable to different-scale solar chimney thermal power generating systems. 4. for a required electric power output, it can obtain many combinations of chimney and collector dimensions by the simulation. 5. the chimney couldn’t produce suitable power for low chimney height and small base area, for low chimney height it is preferred to the desirable enhancement for increasing the chimney power generation is reducing its exit area. 6. the optimum collector area and chimney height could be chosen for required output power, we only need to take some measurement at sites. 7. it is convenient to choose the chimney site within acceptable annual average ambient temperature. 8. the chimney power increases rapidly as the sizes of collector and the chimney are increases, but al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 358 the percentage development in chimney power is reduced with an increase in their sizes so that it will be useless economically . references  al-heaty r.d., ''using finite element method for the performance analysis of solar chimney'', msc. thesis ,nahrain university,baghdad,2002.  dai y.j., huang h.b., wang r.z., "case study of solar chimney power plants in northwestern regions of china", renewable energy, vol.28, issue 8,pp.1295-1304, www.linkinghub.elsevier.com/retrieve/pii/s0960148102002276, july2003.  duffie j.a. and beckman w. a., "solar engineering of thermal processing", mcgraw-hill book company 1991.  gan g. and riffat s. b.,'' a numerical study of solar chimney for natural ventilation of buildings with heat recovery'', applied thermal engineering, volume 18, issue 12, pages 11711187 , december 1998.  haaf w., ''preliminary test results from the manzanares pilot plant'', international journal of solar energy, vol.2, 1984.  haaf w., friedrich k., mayr g., schlaich j., '' principle and construction of the pilot plant in manzanares'', international journal of solar energy,vol.2, no.1,pp.3-20,1983.  holman j.p., ''heat transfer'', mcgraw-hill book company ,new york, 1989.  jackobs e.w. and lasier d.d., ''theoretical analysis of solar driven nature convocation energy convocation system'', internal report, solar energy research institute, golden co.january 1984.  kays w.m., ''convection heat and mass transfer '', mcgraw-hill book company ,new york, 1966.  koonsrisuk a. and tawit chitsomboon,'' partial geometric similarity for solar chimney power plant modeling '', solar energy, volume 83, issue 9, pages 1611-1618, www. linkinghub.elsevier.com/retrieve/pii/s0038092x09001200 , september 2009.  koonsrisuka a., lorenteb s. and bejanc a., '' constructal solar chimney configuration '', international journal of heat and mass transfer, volume 53, issues 1-3, pages 327-333, 15 www.linkinghub.elsevier.com/retrieve/pii/s0017931009005079 january 2010.  maad r. and belghith a., ''use of grid generated turbulence to improve heat transfer in passive solar system'', renewable energy,vol.3,pp.333-336,1992.  mullett l.b.,''the solar chimney overall efficiencies, design and performance'', international journal of ambient energy,vol.8,pp.35-40,1987.  rehealt s. and bilben e.,'' developing laminar convection between non-isothermal vertical plates'',asme, heat transfer division, vol.104,part3,pp.103-108,1988.  schlaich j., the solar chimney: ''electricity from the sun, axel menges, geislingen, germany, 1995.  toufik chergui, salah larbi, and amor bouhdjar." thermo-hydrodynamic aspect analysis of flows in solar chimney power plants—a case study", renewable and sustainable energy reviews volume 14, issue 5, pages 1410-1418, june 2010 .  yaun s.w.,'' foundation of fluid mechanics'', prentice-hill inc. englewood cliffs,new jersy,1967. www.lin www.linkinghub.elsevier.com/retrieve/pii/s0017931009005079 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 359  zhoua x., yanga j., xiao b., hou g., "simulation of a pilot solar chimney thermal power generating equipment", renewable energy, volume 32, issue 10, pages 1637-1644 , www. linkinghub.elsevier.com/retrieve/pii/s0960148106002187, 2006.  zhoua x., yanga j., xiao b., hou g,. "experimental study of the temperature field in a solar chimney power setup", applied thermal engineering, volume 27,issues11-12,pages20442050,www.linkinghub.elsevier.com/retrieve/pii/s135943110600 4315, august 2007. (figure 3) variation of the calculation and simulation output power with the variation of chimney height(m) for different collector areas ac (m2), and ambient temperature t∞=25oc ac= 16 m2 ac= 9 m2 ac= 4 m2 ac= 1 m2 simulated curve calculated curve al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 360 (figure 4) variation of output power (w) with the variation of chimney height and for different ambient temperature (t∞ co), and collector area of 9 m2. (figure 5) comparison between calculated and simulated output power for different ambient temperature t∞ (co) for different chimney height h (m). h= 4 m h= 3 m h= 2 m h= 1 m simulated curve calculated curve al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 361 (figure 6) output power against chimney height for different exit area, and the collector area is 16m2. (a) calculated (b) simulated (figure 7) calculated and simulated power gained from the chimney for collector area (1,3,9,16) m2 and chimney height (1,2,3,4) m . al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 362 (a) data (dai ,2003) (b) simulation study (figure 8) the effect of solar chimney height and diameter of collector on the power generation comparison between data from (dai ,2003) and the simulation present work. h(m) output power(w) h(m) output power(w) t∞=10 oc t∞=20 oc h(m) output power(w) h(m) output power(w) dimensions and parameters used in (dai ,2003)for the solar chimney power plant: chimney height (hsc) 200 m chimney diameter (dsc) 10 m collector diameter (dcoll) 500 m ambient temperature (t0) 20 c al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 363 t∞=30 oc t∞=40 oc (figure 9) effect of the ambient temperature on the power gained by the chimney with different solar chimney heights and collector areas for (ao =0.5 m2). h(m) output power(w) h(m) output power(w) ao=0.7 m2 ao=0.4 m2 h(m) output power(w) h(m) output power(w) ao=0.6 m2 ao=0.3 m2 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 364 h(m) output power(w) h(m) output power(w) ao=0.5 m2 ao=0.2 m2 (figure 10) effect of the outlet area on the power gained with different chimney heights and collector areas for (t∞=25o). (figure 11) the percentage of the gain output power variation with the chimney height. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 291 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. experimental study for behavior of (waste concrete filled steel tubuler) columns subjected to a static axial loads zaid ali kadhim alzaidi roads and transport engineering department, college of engineering, university of al-qadisiyah, iraq e-mail: zaid.alzaidi@qu.edu.iq received on 17 april 2017 accepted on 9 august 2017 abstract: in this study, composite columns have been tested under axial load. the steel tubes were filled with waste concrete to perform the composite action. the specimens divided into two groups; square and circular columns. the diameter of the circular hallow columns was 7.5 cm with 2mm thickness, while the dimension of the square hallow columns was (7.5 cm × 7.5 cm) with 2mm thickness. for each group a column without waste concrete filled steel tubular (w.c.f.s.t) was tested to act as a reference column. load-deflection curves were constructed for all specimens. the results indicate that the waste concrete filled steel tube has more capacity due to the composite action. the pattern of failure in circular sections was different from the failure pattern of the square ones. keywords :w.c.f.s.t columns; load -deflection curves; waste concrete; axial load; pattern of failure . introduction and literature review; steel materials have the advantage of high elasticity, while concrete material have the benefits of high compressive quality and solidness. composite section joins steel and concrete, properties together and make new section that has the useful characteristics of both materials [4] .figure 1 explains waste concrete filled steel tubular (w.c.f.s.t) segments which comprises content of a steel tube filled with waste concrete. the applied load on composite sections (resisted) by both steel and waste concrete by composite action; the composite action depends on the strength of both the steel tube and concrete waste. in order to make the concrete waste more intact, cement mortar was added to each layer of the fill to act as a bonding material. the steel however, plays another role by acting as a confinement element and prevents the crushing of the filler materials. utilizing of composite sections as a part of structures like multistory structures (bridges piers, piles … and [so] far has been a promising systems because of their high (strength)limit, simple development, imperviousness to fire, and flexibility. mailto:zaid.alzaidi@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 292 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 1 figure 1 . the waste concrete-filled steel tubular (w.c.f.s.t) in 2009, ghannam-[1] carried out study on the composite sections of rectangular cross area utilizing eight filled scale samples. in his study, he investigated the strength of lightweight total cement filled steel tube-shaped sections with typical weight total cement. all sections were tried up to the failure. in view of the exploratory results and outline count the light weight total cement utilized as a part of composite segments indicated satisfactory resistance in correlation with plan computation and the conduct of cement (c.f.s.t) sections with ordinary cement was like those obtained from light weight concrete. in 2011, fei-yu et al[2] examined the behavior of composite sections in the presence of a gap between the filling materials and the steel tube. a twenty one examples were tried and partitioned into two gatherings: (fourteen short segments tested under only axial load, and seven bars subjected to flexure. the parameters studied in this research were the gap sort (circumferential or circular top), and hole proportion. in 2012, hafes et al-[3] exhibited a hypothetical and investigational program for short compound sections subjected to stationary concentric and erratic burdens, the test program included trial of six square c.f.s.t segments ,one of the exploratory factors in the experiment is the applied load point. the investigational and hypothetical experiment reasoned that the concentric load enhanced a definitive ability to around 250 – 275% while the eccentric loading expanded a definitive ability to around 307 – 341%. the filling dilation action and the larger cross section area play major role in increasing the capacity limit. in 2012, nie et al-[4] displayed a trial concentrate on the c.s.f.t sections conduct under torsion and pressure – torsion periodic loading. eight (c.f.s.t) samples tried in the experiment. the standards researched in the experiment kind of cross section, strengthen proportion and applied loading level. as a conclusion, the torsional limit of c.f.s.t segments exposed to a pressure – torsion loading expanded in low compressive force. be that as it may, the torsional limit of c.f.s.t segments diminished under the effect of great pressure loading. in 2013, xiushu et al-[5] examined the rectangular c.f.s.t segments exposed to eccentric load .the experimental program contained seventeen rectangular c.f.s.t segments were tried under uniaxial and biaxial twisting burden. the standards concentrated on were ; pressure quality of solid, steel quality. in 2015, alaa hasson et al-[6] studied a compound columns (square and circular) steel with hollow sections these filled with concrete. specimens investigated under the action of concentric and eccentric axial loads for one instance, which those section tried horizontally likewise a beam to calculate the most bending resistant. the objective of this research is to investigate the behavior of circular and square steel tube filled with concrete waste under axial load, and to know the amount of resistance that can be added by the concrete al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 293 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. waste in the case of use as a composite with the steel sections of all kinds for the purpose of benefiting from these composite sections of the construction work. 1. experimental work six segments have been tested in this experiment ,divided into two groups ,one for (square) c.f.s.t columns and the other for circular c.f.s.t columns. the segments used in the experiment are shown in figure 2. figure 2 . (square and circular) supports . each group moreover was divided into two subdivision groups of three segments according to waste filler. the first section of the first group is empty square section (no filler), the second section square is filled with waste of concrete remaining on the sieve measuring (19 mm) as a coarse waste of concrete, the third square is filled with waste of concrete transit sieve (4.75 mm) as a fine waste of concrete. the first of the second set circular section is empty, the second filled with remnants of concrete remaining on the sieve measuring 19 mm, and the third is filled with remnants of a circular concrete transit sieve (4.75 mm) . bearing in mind that the fill section in the form of layers with good compaction. the empty steel segments (square and circular) experienced as stated by (astm a6) to find their yield strength values. the sectional characteristics and yield strength of square and circular sections are concluded as shown in table (1). table 1.segments characteristics of empty( steel columns) steel section dimensions (mm) yield strength (mpa) square section 75×75×2 352 circular section 75×2 327 the segments were tested under axial load by using the testing machine shown in figure 3. each specimen was attached to a bearing plate from the bottom side to help applying the load uniformly to the section. the lateral deflection at the middle of each section was captured by using the dial gauges as explained in figure 3. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 294 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 3. testing machine. each specimen was placed in the loading deck with high accuracy to ensure the alignment of the column. the load then was applied monotonically and the reading of the load and corresponding dial gauges readings were recorded. the characteristics of tested c.f.s.t columns (square and circular) are concluded in table (2) and table (3) respectively. table2 . characteristics of tested (square c.f.s.t) columns column dimensions (mm) yield strength fy (mpa) s1 75×75×2 352 s2 75×75×2 352 s3 75×75×2 352 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 295 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 3. characteristics of tested (circular c.f.s.t) columns column dimensions (mm) yield strength (mpa) c1 75×2 327 c2 75×2 327 c3 75×2 327 2. results based on investigational work explained in section 3. the results are summarized in table 4 and table 5. table 4. patterns of failure and loads for( square w.c.f.s.t )columns column waste concrete type description load (kn) failure pattern s1 no filler 79 steel yielding at end span s2 coarse waste of concrete 86 yielding near the support due to compression failure. s3 fine waste of concrete 129 yielding near the support due to compression failure. table 5. patterns of failure and loads for( circular w.c.f.s.t)columns column waste concrete type description load (kn) failure pattern c1 no filler 86 buckling c2 coarse waste of concrete 139 buckling c3 fine waste of concrete 151 buckling 2.1. load deflection curves: the load deflection curves for square waste filled steel tube columns and circular waste concrete filled steel tube columns are explained in the figure 4 and figure 5 shown below. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 296 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 4. load-displacement relationships of composite specimens of group(1) square w.c.f.s.t columns figure 5 . load-displacement relationships of composite specimens of group(2) circle w.c.f.s.t columns al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 297 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.2. patterns of failure figure 6 shows (square c.f.s.t) segments subjected to axial loading, the failure occurred because waste concrete crushing and steel yielding ( at the loaded ends of the columns).the local yielding failure was observed for (s1,s2,s3) segments due to the direct compression force from the loading deck. figure 6. patterns of failure for square w.c.f.s.t columns subjected to axial loading. figure 7. patterns of failure for circular w.c.f.s.t columns subjected to axial loading. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 298 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 7 shows ( circular c.f.s.t) segments subjected to axial loading ,the failure was due to the axial buckling at nearly the middle of the columns. conclusion; three composite square waste filled steel tube columns and three circular waste concrete filled steel tube columns were investigated for their axial strength. from the obtained date, the following points can be concluded: 1. it is appeared from the results that the (w.c.f.s.t) segments generally have a limited increasing in axial load. 2. in axial loading case, the square w.c.f.s.t segments, the failure was due to steel yielding or waste concrete crushing while in circular w.c.f.s.t sections the failure occurred because of the buckling since the moment of inertia of the square segments (slightly) greater than the circular section. buckling accrued first in circular section while the square section failed by yielding the steel material. 3the results proved that the waste concrete can be reused as filler in composite columns since give a reasonable strength has been obtained. on other word, this technique can be considered as sustainable method. reffrences; 1. ghannam s. behavior of composite steel columns filled with normal concrete and others filled with light weight concrete. proceeding of 3 rd engineering work consultative conference, palestine , 2009. 2. fei-yu l., lin-hai h., and shan-hu h. behavior of c.f.s.t short column and beam with initial concrete imperfection. journal of constructional steel research, vol. 67, issue 12, pp , 2011. 3. hafes l. m., tawfic y. r., sdeek a. b., and abdelazeem m. theoretical and experimental study for the behavior of short composite columns tested under static centric or eccentric loads. journal of engineering sciences, assist university, vol. 40, no 3, pp.639-655 , 2012. 4. nie j., wang y., and fan j. experimental study on seismic behavior of concrete filled steel tube columns under pure torsion and compression–torsion cyclic load. journal of constructional steel research, vol. 79, pp. 115-126, 2012. 5. xiushu q., zhihua c., and guojun s. experimental study of rectangular c.f.s.t columns subjected to eccentric loading. thin-walled structures, vol. 64, pp. 83-93, 2013. 6. sa'ad fahad resan. experimental investigation of aluminumlightweight concrete composite columns. basrah journal for engineering sciences,vol.14 , pp 13-26,2014. 7. alaa hadi hameed hassoon. experimental study for the interaction curves of c.f.s.t columns subjected to a static centric or eccentric loads. journal of thi-qar university vol.11 no.2 june ,2016. 3-2-2011.pdf 26 theoretical and experimental investigations of composite material as thermal insulation consists of natural fibers (white feather, jute, egg shell, and black feather) are present in this work. the experimental works are divided into two parts. the first part involved with the study of the thermal conductivity of the composite materials. lee’s disc method is used to measure the thermal conductivity of different types of natural composite materials. these values are compared with theoretical values of thermal conductivity calculated using maxwell model. the effect of volume fraction on thermal conductivity is studied. the second part included building two rigs which have the dimensions (1m x 1m x 1m). the first rig used as reference and the second rig to measure the temperature distribution on the lower surface of the roof insulation. the effects of change in volume fraction, air gap, and types of natural composite insulation on temperature reduction are investigated. the results show that the (jute composite material) gives good results as composite thermal insulation compared with other natural composite materials. ) (ِ . : ).لي –( ) .( . )١x١x١ ( ، . ، ، . . 27 d diameter of sample m iv rate of energy supply to the heater w k thermal conductivity of composite w/m.k k1, k2,…,kn thermal conductivity of each layer of roof assembly w/m.k kf thermal conductivity of fiber w/m.k km thermal conductivity of matrix w/m.k q total heat gain w v volume of sample m3 vf volume fraction -------vfiber volume of fiber m3 vtotal total volume m3 ta, tb, and tc temperature of disc a, b, and c in lee’s disc technique c ts specimen thickness m r radius of disc m a natural composite is a material formed by a matrix (resin) and a reinforcement of natural fibers (usually derived from plants or cellulose). natural fibers have low thermal conductivity so this will give good ability for insulation with other materials. high aspect ratio (length/diameter) permits effective load transfer via the matrix ( ). natural fibers are grouped into three types: seed hair, bast fibers, and leaf fibers, depending upon the source. some examples are cotton (seed hairs), ramie, jute, and a flax (bast fibers), and sisal and abaca (leaf fibers). of these fibers, jute, ramie, flax, and sisal are the most commonly used fibers for polymer composites ( ). ( ) used jute fiber nonwoven mats to reinforce resin transfer molded unsaturated polyester-styrene panels. tensile strength and flexural modulus for unmodified jute samples were half that of samples made with a commercial glass mat. jute fiber pull-out from the matrix was seen in scanning electron micrographs, which indicates that improving adhesion at the fiber-polymer interface may increase mechanical properties. ( ) presented a comparison analysis of thermal insulation properties such as thermal conductivity, absorption and thermal resistance of fabrics made of cotton and tencel. the finished fabrics made of tencel yarn showed lower values of thermal conductivity and thermal absorption then fabrics made of cotton yerns, and higher values of thermal diffusion and resistance. ( ) made a series of aspen fiber medium density fiberboard panels adding various levels of chicken feather fiber to determine the relative effect of the feather fiber-wood fiber mixtures on composite panel properties. the mechanical properties show some loss in strength and stiffness for feather fiber-wood fiber mixtures when compared to the properties of all-wood control panels. the physical properties of feather fiber-wood fiber mixtures showed a marked improvement in resistance to water absorption. ( ) deals with the effect of natural fibers on thermal and mechanical properties of natural fiber polypropylene composite using dynamic mechanical analysis. results indicated that glass transition was slightly shifted to lower temperature in composite. transition temperature was higher in case of composite and intensity was higher as well. ( ) have been characterized the physical and mechanical properties of chicken feather materials cfm. results describing the moisture content, aspect ratio, apparent specific gravity, chemical durability, young’s modulus, and tensile strength for processed cfm. ( ) obtained short fibers form poultry feathers to possess high toughness, good thermal insulation properties, non abrasive behavior and hydrophobic nature. mechanical properties such as tensile strength, and flexural strength were 28 evaluated. it was found that the material loss from the composite surface depends greatly on operational variables like impact angle, impact velocity etc. in this work the white feather, jute, egg shell, and black feather were taken up and studied the thermal properties of them, also used them as thermal insulation on roof surface. the density of the composite materials "thermal insulation" is found by measuring the weight and volume of the component of composite materials samples. the weight is found by using an electronic portion scale (up to 2000g). the thickness of each type of fiberglass was found by using dial calipers. the dimension of composite materials samples are (0.6 cm) thickness and (4 cm) diameter. the volume of each sample is found using equation (1). the measurement of weight and thickness were repeated three times for all types of natural fiber samples. an average value was taken for the calculations in this part. then the density is calculated from volume and weight. the same procedure is repeated to determine the density of polyester resin which is found to be 1.1 g/cm3. shows the experimental result of density for different natural fibers used in this work. after determining the density and volume for each type of fiber, the volume fraction of each insulation type can be determined using the following relation. total fiber f v v v (2) the volume fraction is the ratio of fiber volume in composite to the total volume of composite which is consists of fiber and matrix (polyester resin). in this work many volume fraction are taken for different types of natural composite materials. the thermal conductivity of natural composite materials depends on thermal conductivity of natural fiber, thermal conductivity of matrix, and the value of volume fraction. maxwell model ( ) is used to calculate theoretically the thermal conductivity of the samples of thermal insulation used in this research using equation (3). 2 22 (3) the cast iron mold is used to fabricate a samples of natural composite materials used to measurement the thermal conductivity using lee’s disk method, the cast iron mold was cleaned from dirt and then smeared with special oil to prevent direct contact between the sample and the mold, see .the specimen have dimension of 4cm x 0.6cm as shown in . casting is put under load for about one to two hours for proper curing at room temperature will produce the samples shown in . thermal conductivity coefficient of specimens was measured using lee’s disk method principle ( ). the apparatus shown in consists of four identical discs of 4 cm k = s t*d*)4 (v 2 (1) 29 in diameter and 0.6 cm thickness. one of them includes an electrical heater denoted by (h). the specimen (s) with 4 cm in diameter and (0.6 cm) thickness was placed between the discs (a) and (b), as shown in . the heater (h) was sandwiched between the discs (b) and (c). temperature of (a), (b) and (c) discs were measured using three thermocouples type (k). the temperature of the ambient was measured too. heat was supplied with a 12 volt d.c. power supply and the current i was found to be equal to 0.26 amp. the rate of supply energy was noticed (iv). when the discs were assembled they are vanished to give them the same emissive, and the whole apparatus was suspended in an enclosure of constant temperature. total heat (q) can be obtained in terms of supply energy (iv), since the total heat supplied must be equal to that given up by the various surfaces ( ): 2 (4) so, thermal conductivity coefficient becomes: ( ) 2 ) 4 ( 2 )( (5) the average of five measurements was taken for each specimen to minimize the possible errors. thermal conductivity of samples was then calculated theoretically by using maxwell model as illustrated above where comparisons between theoretical and experimental results were accomplished. the composite plates used in this work consists from natural fiber (four types show in ) and matrix (polyester resin with hardener 4%), without adding the hardener the polyester will stay liquid. to fabricate the composite plate of size (500mm x 500mm) with 6mm thickness as shown in , the mixture (natural fiber and matrix) is cast in mould which made from glass show in . this operation are done in a closed space and used buffer material to avoid direct contact between the specimen and the mould surface .after molding the sample insulating cover is used and apply distributed load to avoid keeping any air gap trapped in the sample for about 24 hours at room temperature. to investigate the effect of thermal insulation (natural composite material) on the roof, two rigs were building to study the temperature fluctuation when the thermal insulation is installed. the two rigs are similar in construction and dimensions, their dimension (1m x 1m x 1m) as shown in ; the first rig is used as a reference to indicate the temperatures of the rig without thermal insulation and to compare it with the temperature of the second rig with the thermal insulation. the model is consist of an iron structure which is able to hold the weight of concrete roof which is located above the iron structure, the roof is made of concrete and its dimensions are (1m x 1m x 0.12m) to simulate the construction in iraqi buildings. the structure of walls is made of (6 cm thickness) polystyrene to eliminate the effect of temperature gain through the walls of the models .the thermocouples are used to determine the temperature of the rigs and they are distributed on the bottom surface of the roof. five thermocouples type (k) range (-30 cº to 110 cº) are used in order to avoid the error that may be happen and in average temperature of thermocouples in each location in the model are taken and the temperature will measured and listed in hourly in all days of experimental work. the thermal insulation will put on the top of the concrete roof with and without 30 air gap. the air gap (if it’s found) is put between the top surface of the concrete roof and the natural composite insulation, and it was 2cm above the roof. this section includes experimental and theoretical results of the present work. theoretical results represent the thermal conductivity of different type of natural composite materials with different volume fraction. the effects of different types of natural composite materials (thermal insulation) and the volume fraction on the temperature reduction of roof with and without air gap are also investigated. the effect of volume fraction on thermal conductivity of composite material "thermal insulation" was investigated in this section. represents a comparison between experimental and theoretical results of thermal conductivity varying with volume fraction using white feather. theoretical results are calculated using maxwell model [see equation (3)]. from this figure, it can be seen that the experimental results gives accepted results in comparison with theoretical result, and with a maximum error percentage of (18.7 %). the thermal conductivity is decreasing with increasing the volume fraction due to increasing the white feather in composite insulated. the same comparison between volume fraction and thermal conductivity was repeated for black feather, egg shell, and jute in respectively. the maximum error percentage was found (14.5%), (18%), and (10.5%) respectively. shows the experimental relationship between volume fraction and thermal conductivity for different types of natural fibers. it is clear that the thermal conductivity decreases with increasing of volume fraction due to increasing the volume of natural fiber in composite sample which has less thermal conductivity than polyester resin, and the figure shows that the composite of jute have lower thermal conductivity than other types because the jute fiber has thermal conductivity less than the other natural fiber. temperature of roof varies throughout the day due to solar radiation. it is also an effective indicator for heat transfer inside the space. investigating the efficiency of composite materials as thermal insulation on roof requires measuring the temperature distribution on lower surfaces of the roof, with and without the insulation. the thickness of different natural thermal insulations was 6mm as explained in section 5. all the daily data was collected from 7 a.m. to 4 p.m. shows the daily temperature reduction with local day time on roof lower for white feathers composite insulation with 2cm air gap with different volume fraction. temperature reduction is calculated from:rigrefrencefromriginsulatedcompositenaturalfromreduction ttt (6) from this figure, it is clear that increasing volume fraction causes increasing in temperature reduction due to decreasing of matrix (polyester) which have thermal conductivity higher than thermal conductivity of fiber (natural fiber). this caused in increasing thermal conductivity of natural composite insulation. repeated same parameters in except removing air gap. from this figure, it can be seen that, increasing volume fraction causes decreasing temperature reduction. from figures (13, and 14), using composite insulated with air gap 2 cm thickness causes increasing in temperature reduction comparison with insulated without air gap because the air has low thermal conductivity. the maximum temperature reduction was found (16.2 co and 12.2 co) in figures (13 and 14) respectively, it was occurs between 12 p.m. to 2 p.m. due to increasing the solar radiation at these time give the temperature reduction for black feather with and without air gap respectively with changing volume fraction. maximum temperature reduction was found (12.1 co 31 and 9.6 co) in figures (15) and (16) respectively. give same relationships as in figures (15) and (16) but now for egg shell natural composite material figures (17 and 18) and jute natural composite material figures (19) and (20). from these figures the maximum temperature reduction with and without air gap were (10.3 co and 7.1 co) for egg shell insulated (see figures (17) and (18)) and (16.8 co and 11.6 co) for jute insulated (see figures (19) and (20)). from figures ( 13), (14), (15), (16), (17), (18), (19), and (20), it can be seen that, the increasing volume fraction causes increasing temperature due to decreasing thermal conductivity of natural composite insulated. also, using air gap will increasing reduction in temperature because the air gap has small value of thermal conductivity. gives the relationship between temperature reduction and the local time for different types of natural composite materials with (10 %) volume fraction and with air gap. from this figure, the natural composite plate made from jute given reduction in temperature greater than other types of natural materials, and the egg shell natural composite materials gives minimum temperature reduction. give same relations as figure (21) with (30%, and 60%) volume fraction respectively. from these figures, it can be concluded that the jute natural composite insulated gives maximum reduction in temperature. also, the increasing volume fraction will be increasing temperature reduction due to increasing volume of fiber which has thermal conductivity higher the matrix in composite plate. many conclusions can be noticed from the present work which can be summarized, as follows: 1) increasing volume fraction of natural fibers causes decreases in thermal conductivity and increases in temperature reduction of the roof. 2) the jute gives minimum thermal conductivity compare with other natural composite materials. 3) the maximum reduction of temperature is occurred in the period between (12 p.m._2 p.m.). 4) the jute and white feather gives maximum reduction in temperature comparing with other natural composite materials. 5) the air gap increases the temperature reduction. 6) finally, the natural composite materials can be used as thermal insulation. 1) duncan m. price, mark jarrat, “thermal conductivity of ptfe and ptfe composites", thermo chi mica act 392-393 (2002). 2) faieza m. saleem;" thermal and mechanical investigation of fiber reinforced epoxy" ph.d thesis, mech. eng. department, university of technology, iraq, 2006. 3) i. frydrych, g. dziworska, j. bilska ;” comparative analysis of the thermal insulation properties of fabrics made of natural and man-made cellulose fibres”, fibres & textiles in eastern, october/december 2002. 4) jane l. o’dell,” natural fibers in resin transfer molded composites”; the fourth international conference on woodfiber-plastic composites, may 12-14, 1997. 5) jerrold e. winandy1, james h. muehl1, jessie a. micales1, ashok raina and walter schmidt;” potential of chicken feather fibre in wood mdf composites “queen mary, university of london september 1-2, 2003. 6) jeffrey w. kock;” physical and mechanical properties of hicken feather materials”, m.sc. thesis. school of civil and environmental engineering, georgia institute of technology, may, 2006. 32 7) mehdi tajvidi, robert h. falk, john c. hermanson;” effect of natural fibers on thermal and mechanical properties of natural fiber polypropylene composites studied by dynamic mechanical analysis” journal of applied polymer science, vol. 101, 4341–4349 (2006). 8) v. ananda rao, alok satapathy, s.c. mishra,” polymer composites reinforced with short fibers obtained from poultry feathers “’ national institute of technology, rourkela 769008, india, december 12-14, 2007. 9) yan li, chunjing hu, yehong yu, “interfacial studies of sisal fiber reinforced high density polyethylene (hdpe) composites”, composites part. 2007 (in press). density of difference natural fibers. fibers whitefeather black feather egg shell jute density 3cm g 0.89 0.89 1.65 1.46 jute black feather egg white feather f th natural composite disc. cover die punch iron mold for lee’s disc technique. 4 cm 0.6 cm sample dimensions of lee’s disc technique. 33 disc sample s disc b heater h disc c lee’s disc arrangement. natural composite plate. glass casting mold mold cover 50cm 50 cm schematic of glass mold. 34 experimental rigs. 35 36 8-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۳ numerical analysis of free convection in a square and in a rightangle trapezoidal enclosure filled with porous medium dr. falah a. abood mechanical engineering department college of engineering basra university abstract: a numerical study is conducted to investigate the natural convection heat transfer in a two cases of the enclosure ,the first case in a square enclosure of aspect ratio ar=1 and the second case in a right-angle trapezoidal enclosure with aspect ratios ar=0.45 and 0.25 .the enclosure was filled with a liquid saturated porous media .the bottom wall of the cavity was heated with a sinusoidal temperature distribution θ=0.5(1-cos(2πx)) , the vertical wall was cooled at θ=0 and the other walls were adiabatic. the governing equations were solved numerically using finite element software package (flexpde). flow and heat transfer characteristics are studied for the range of rayleigh number (100 ≤ ra ≤ 1000). streamlines, isotherms and nusselt numbers were presented. the obtained results show that the heat transfer coefficient increases with increasing of rayleigh number and aspect ratio. a comparison of the flow field and isotherm field was made with that obtained by (yasin et al., 2008), which revealed a good agreement. keywords: free convection, trapezoidal enclosures, porous medium . -: ، ar=1ar=0.45ar= 0.25 . .θ=0.5(1cos(2πx)) θ=0 . )flexpde ( " .) .(100 ≤ ra ≤ 1000 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦٤ arra .(yasin et al., 2008) . nomenclature ar aspect ratio parameter h/l g acceleration due to gravity m/s2 h length of the top wall of the cavity m k permeability of the porous medium m2 l length of the bottom wall of the cavity m nul local nusselt number num mean nusselt number ra rayleigh number ra=gβk (th-tc)/υα t temperature of the fluid porous medium u, v velocity components, ul/α , vl/ α x, y non-dimensional coordinates, x=x/l, y=y/l greek symboles α thermal diffusivity of porous media m2/s β thermal expansion coefficient k-1 θ dimensionless temperature, θ=(t-tc)/( th-tc ) υ kinematics viscosity m2/s ψ dimensionless stream function subscripts c cold h hot l local m mean introduction: buoyancy induced convection and fluid flow in enclosures filled with fluid –saturated porous media can be seen in many applications in , solar power collectors , geothermal applications , double wall insulation , electric machinery , cooling system of electronic devices , natural circulation in the atmosphere , molten core of the earth , induces fibrous insulation , food processing and storage , thermal insulation of the buildings , geophysical systems , electro chemistry , metallurgy , the design of pebble bed nuclear reactors , underground disposal of nuclear or nonnuclear waste , etc. a great number of studies are related with the analysis of natural convection in square and rectangular enclosures. some important numerical results can be found in the studies by (bejan and tien, 1978). (poalikakos and bejan, 1983) reported exact analytical solution of natural convection in an attic-shaped space filled with porous material. natural convection heat transfer and fluid flow was studies for porous or non-porous medium trapezoidal enclosures mostly at differentially heated temperature boundary conditions see (kuypor and hoogendoom, 1995). (sadat and salognac, 1995) , (moukalled and acharya, 2001) , (bayates and pop ,2001) , ( moukalled and darwish , 2003 ), (kumar and kumar, 2004 ) , ( baytas et al.,2000 ) presented a numerical study of natural convection in a two dimensional right angle triangular cavity filled with a fluid saturate porous medium using the darcy–bousseinesq equation media. some studies also have been performed to investigate the effect of boundary conditions and the effect of inclinations on natural convection in square/rectangular enclosures filled with porous media or viscous fluids (saeid, 2005) and (oztop and varol, 2007). the natural convection heat transfer in triangular enclosure has been studied by (varol et al., 2007). number of papers on natural convection flows in trapezoidal cavities filled with porous media (basak et al., 2009) and (varol et al., 2009). a numerical study of the steady buoyancy –induced flow and heat transfer in a trapezoidal cavity filled with a porous medium saturated with cold water has been performed by al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦٥ (yasin et al., 2010). thus the main objective of this paper is to examine the natural convection in a square cavity and in a right-angle trapezoidal filled with a porous medium. different rayleigh numbers and different aspect ratios were considered in these studies. the governing equations were solved numerically using finite element software package (flexpde) governing equations: a schematic of the two dimensional square enclosure and a right angle trapezoidal enclosure filled with saturated porous medium is shown in fig.1 (a) and (b) respectively. the bottom wall of the cavity was heated at sinusoidal temperature distribution and the top wall was cooled, while the remaining walls were insulating. the governing equations for the study, two dimensional, incompressible flows with darcyboussinseq approximation and constant fluid properties can be written in non-dimensional form as follows: 0 y v x u (1) x ra yx 2 2 2 2 (2) 2 2 2 2 yxyxxy (3) where the dimensionless variables are defined as: ch c tt ttvl v ul u l y y l x x ,,,, (4) here x and y are the cartesian coordinates along the horizontal and vertical walls of the enclosure, respectively, u and v are the velocity components along the xand ydirection , θ is the nondimensional fluid temperature , ψ is the non-dimensional stream function , which is defined as : x v y u , (5) where k is the permeability of the porous medium and α is the diffusivity of the fluid. the boundary conditions of eqs (1-3) shown in fig.1 are: 1-no-slip velocity boundary condition, u=0, v=0 and ψ=0 on all solid walls. 2sinusoidal temperature distribution on the bottom wall θ=0.5 (1-cos (2πx)), θ=0 on the top wall and 0 n on the other walls; where n denotes the direction normal to the adiabatic walls of the enclosure. besides the streamlines and isotherms, the physical quantities of interest in this problem are also the local nusselt number nul, and the mean nusselt number num from the heated wall, which are given by: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦٦ 0y l y nu , dxnunu lm 1 0 (6) numerical solution: in the present study, a finite element software package flexpde (backstrom, 2005) is relied in the solution of the nonlinear system of equations (2) and (3). hence, the continuity equation (1) is used to check the error of the solution throughout the grids of domain. software validation to check the validation of software, three grid densities were examined 10-3, 10-4, and 10-5. the grid dependency was checked with the continuity equation and the obtained results show the exactly validated of the velocity distribution for each above grid densities. i.e example, the griddled domain for the trapezoidal enclosure of ar=0.25 is shown in fig.2a and the distribution of the values of (∂u/∂x + ∂v/∂y) over the domain, is presented in fig.2b. code validation to check the validity of the numerical results, test calculations were performed for the triangular cavity filled with porous medium for ra=1000. the boundary condition of the bottom wall is non-isothermally heated wall θ=0.5(1-cos (2πx)) and the vertical wall at θ=0, while the inclined wall is kept adiabatic. the program was verified by a comparison with a theoretical work performed by (yasin et al., 2008) as shown in fig.3, who developed numerical results for the streamlines and isotherms in the triangular cavity filled with porous medium. the results show a very good agreement and from this comparison it can be decided that the current code can be used to predict the flow field for the present problem. results and discussion: the results of the flow fields and heat transfer for porous non-isothermally heated square and trapezoidal enclosures are studied in this paper. the temperature of the bottom wall is taken as sinusoidal temperature distribution θ=0.5(1-cos(2πx)) and the upper wall is θ=0 while the other walls are taken as adiabatic . fig.4 (a) shows the streamlines (on the left) and the isotherms (on the right) in a porous square enclosure for ar=1 and ra=100. it can be noted from this figure the double circulation cells were formed in vertical position, and the rotating direction is starting from middle of the bottom wall. for the trapezoidal enclosure ar=0.45 and 0.25 as given in fig.4b(left) and fig.4c (left) respectively , two cells were formed inside the enclosure with different rotation direction , the right cell is the dominated in the cavity . the left cell is located at the bottom corner due to effect of inclination of the left wall. the intersection of the isotherm lines near the corners with the bottom wall show that there is no heat transfer to the fluid , though most of the heat is transfer from the bottom wall toward the fluid. for small rayleigh number the temperature distribution is the same as for pure conduction case, the isotherms show wavy variation and no vortices are observed. as shown from fig.4a(right), for square cavity, the isotherms have a plum like distribution formed in middle of the bottom wall toward the upper wall , while for trapezoidal cavity ar=0.45 and 0.25 the plumes have skew ness toward the inclined adiabatic wall as shown in fig.4b(right) and fig.4c(right) respectively . fig.5 shows the effect of the aspect ratio on the flow and temperature fields for high rayleigh number ra=1000. as can be seen from the streamlines plot of fig.5a(left) , that two circulation cells were formed and inclined at angle 68 o from horizontal , the flow strength is higher than that of fig,4a(left) . also it can be seen from fig.5 (b) (left) and fig.5c (left), the size of the cells is decreased with decreasing of the aspect ratio. isotherms plot of fig.5a (right) shows that, with high rayleigh number the plum like distribution which generated from the bottom wall is occupied the whole space due to the increasing of the convection heat transfer. also it can be seen from fig.5 b(right) and fig.5 c(right), the skew ness of al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۷ the plum toward the left corner of the enclosure is more than that of fig.4 b(right) and fig.4 c(right) due to the dominant of the natural convection with increasing of rayleigh number . variations of the local nusselt number along the bottom wall for square and trapezoidal cavity at different values of aspect ratio and rayleigh number are presented in figs.6 9 . as shown from fig.6 , for the square enclosure ar=1 and with ra=100, a symmetric variation of the local nusselt number along the bottom wall is formed due to the symmetry in the temperature filed. the values of the local nusselt number are negative near the corners of the bottom wall since the direction of the heat transfer is reversed in this rejoin. a positive value of the local nusselt number is observed in the main part of the bottom wall depends on the recirculation intensity. it is clear from this figure , the value of nul is small at the middle of the bottom wall due to the reducing of the recirculation intensity. also it can be seen from fig.6, for the trapezoidal enclosure ar=0.45 and ar=0.25, the maximum value of the local nusselt number occurs at the right half part of the bottom wall. the values of the local nusselt number are increases with increasing of the trapezoidal aspect ratio due to the effect of the inclined adiabatic wall. the heat losing from the left corner of the trapezoidal cavity is decreased with decreasing of the aspect ratio. fig.7 shows the variation of the local nusselt number along the bottom wall for ra=1000. the trend of the curves is the same as that in fig.6 , but the values of the local nusselt number are higher. figs. 8-9 show the increases of the local nusselt number with increasing of rayleigh number along the heated wall of the square and trapezoidal enclosure respectively due to dominant of the natural convection. the negative values of the local nusselt number near the corners of the bottom wall of the square cavity are increases with increasing of rayleigh number as shown in fig.8 this is because of the increasing of the intensity of reversal stream lines. as can be seen from fig.9, at the left corner of the trapezoidal cavity the losing of the heat is increased with increasing of rayleigh number. however, the local nusselt numbers are negative at the corners of the bottom wall due to losing of the heat; positive values are observed in most part of the bottom wall which depends on the direction of the recirculation. thus, the mean nusselt numbers were found to be positive and presented in fig.10. it can be seen from this figure, the mean nussselt number for the square enclosure are higher than of trapezoidal enclosure. this is because of the heat transfer from the fluid losing through the bottom wall of trapezoidal cavity is higher then of the square cavity. conclusions: a numerical study was performed to investigate the flow and temperature fields for the square and trapezoidal porous enclosure. based on the obtained results in the present study, findings are: 1-the flow and temperature fields are strongly depending on the aspect ratio and rayleigh number. for the square cavity asymmetry distribution of the streamlines and isotherms, while the distribution of the flow for the trapezoidal cavity is occur near the left part of the bottom wall. 2-aspect ratio affects the amount of the circulation mass inside the enclosure and the heat transfer is increases with increasing of the aspect ratio ,this mean that the heat transfer from the bottom wall of the square enclosure is higher then that of the trapezoidal enclosure . 3-the overall heat transfer coefficient is an increasing function of rayleigh number. conduction becomes dominants at small rayleigh number. references: 1backstrom gunnar (2005) "fields of physics by finite element analysis using flexpde" by gb publishing and gunnar backstrom malmo, sweden 2bejan.a , c.l tien (1978) " nutural convection in a horizontal porous medium subjected to an end-to-end temperature difference " asme.j, heat transfer,100, 191-198. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۸ 3basak.t , s.roy , a.singh , i.pop (2009) " finite element simulation of natural convection flow in a trapezoidal enclosure filled with porous medium due to uniform and non-uniform heating " int. j heat mass transfer 52, 70-78 . 4baytas.a.c , i.pop (2001) " natural convection in a trapezoidal enclosure filled with a porous medium " int ,j. heat mass transfer 39 ,125-134 . 5baytas.a.c , l. ali , i.pop (2000) " free convection in triangular enclosure filled with a porous medium " proceeding of the 12th turkish national conference on thermal science and technologies , sakarya university , 417-422 . 6kumar.b.v.r , b.kumar (2004) " parallel computation of natural convection in trapezoidal porous enclosures " math . comput .simul . 65 , 221-229 . 7kuyper.r.a , c.j.hooendoorn (1995) " laminar natural convection flow in trapezoidal enclosures " numer. heat. a28. 55-67. 8moukalled.f s. acharya (2001) "natural convection in a trapezoidal enclosure with offset baffles " j. thyrmophys . heat transfer. 15, 212-218. 9moukalled.f , m.darwish (2003) " natural convection in a partitioned trapezoidal cavity heated from the side num .heat transfer " a 43 , 543-563 . 10oztop.f.h , a.varol (2007) " natural convection in partially cooled and inclined porous rectangular enclosures " int . j . thermal .sci . 46, 149-156 . 11poulikakos.d , a. bejan (1983) " numerical studies of transient high rayleigh number convection in an attic-shaped porous layer " j.heat transfer 105 , 476-484 . 12sadat.h , p.salagac (1995) " further results for laminar natural convection in a two dimensional trapezoidal enclosure " numer .heat transfer , a27 ,451-459 . 13saeid.n.h , i.pop (2005) " natural convection from a discrete heater in a square cavity filled with a porous medium " j. porous medium 8,55-63 . 14varol.y , h,f.oztop , a. varol (2007) " natural convection in porous triangular enclosure with a solid adiabatic fin attached to the horizontal wall " int . comm. heat mass transfer 34 . 19-27 . 15varol.y , h.f. oztop, i.pop (2009) " natural convection in right-angle porous trapezoidal enclosure with partially cooled from inclined wall " int. comm. heat mass transfer 36 . 6-15 . 16yasin varol , hakan f.oztop , ioan pop (2010) "maximum density effect on buoyancy driven convection in a porous trapezoidal cavity " int .comm. heat and mass transfer 37 , 401-409 . 17yasin varol, hakan f. oztop, moghtada mobedi , ioan pop. ( 2008 ) " visualation of natural convection heat transfer using heat line method in porous non-isothermally heated triangular cavity " int. j. heat and mass transf. (51) 5040-5051. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۹ fig. 2 for 10-5 accuracy (a) grid distribution over the domain ( b) validation of ti it ti (a) present fig. 3. comparison of streamlines and isotherms at ra =1000 with results of ( yasin et al., 2008 ) (yasin et al. , 2008) ∂θ⁄ ∂n=0 fig.1 schematic diagram of the physical domain a) square cavity b) trapezoidal cavity θ=0 ∂θ⁄ ∂n=0 θ=0.5(1-cos(2πx)) l porous media ∂θ⁄ ∂n=0 θ=0.5(1-cos(2πx)) θ=0 l ∂θ⁄ ∂n=0porous media (a (b y x l h al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۷۰ fig.4 streamlines (left) isotherms (right) at ra=100 a) ar=1 b) ar=0.45 c) ar=0.25 (a) (b) (c) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۷۱ fig.5 streamlines (left) isotherms (right) at ra=1000 a) ar=1 b) ar=0.45 c) ar=0.25 (a) (b) (c) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۷۲ 10 -5 0 5 10 15 20 0 0.2 0.4 0.6 0.8 1 ar=1 ar=0.45 ar=0.25 -6 -4 -2 0 2 4 6 8 0 0.2 0.4 0.6 0.8 1 ar=1 ar=0.45 ar=0.25 nul nul x x fig.7 variation of local nusselt number along the bottom wall , ra=1000 fig.6 variation of local nusselt number along the bottom wall , ra=100 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲۷۳ 1 0 5 0 5 1 0 1 5 2 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 r a =1 0 0 r a =4 5 0 r a = 1 0 0 0 fig.9 variation of the local nusselt number along the bottom wall of the trapezoidal enclosure , ar=0.25 0 2 4 6 8 0 4 0 0 8 0 0 1 2 0 0 a r = 1 a r = 0 . 2 5 num nul x 1 0 5 0 5 1 0 1 5 2 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 r a = 1 0 0 r a = 4 5 0 r a = 1 0 0 0 fig.8 variation of the local nusselt number along the bottom wall of the square enclosure , ar=1 nul x ra fig.10 variation of the mean nusselt number with rayleigh number for the square enclosure ar=1 and the trapezoidal enclosure ar=0.25 . <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 1 the influence of low cost filler on some mechanical and physical properties of a polymer matrix composite orhan sabah abdullah assistant lecturer u.o.technology mechanical eng. dep. orhan_sabah@yahoo.com received on 15 june 2016 accepted on 30 november 2016 abstract experimental study has been done in this research to explain the influence of low cost fillers contents on the mechanical and physical properties of unsaturated polyester resin composite with different weight fraction. the effect of three particles; baby powder particles including mgo, fire extinguisher particles including caco3 and chalk particles including sio2 with weight fraction of (5%, 10%, 15%)wf% added to polyester matrix on the wear rate under dry sliding conditions, hardness, thermal conductivity, and water absorption has been investigated. the wear rate was measured according to astm g99-05 standard with pin on disc machine, hardness measured according to astm d-2240 shore d hardness test, lee's disc technique used to measure thermal conductivity, while water absorption measured according to astm d 570 standard. the results shows that the addition of fillers leads to increasing the wear resistance, hardness and water absorption and decrease the thermal conductivity with the increasing in reinforcement material weight fraction. while, the wear resistance decreasing with increase in applied load. the results appeared that the addition of particles to polyester resin leads to increase in all the mechanical and physical properties tested in this research better than polyester specimen only and mgo-polyester composite given the best wear resistance. keywords: polyester composite; mgo, sio2, caco3; wear behavior, hardness…etc. بولیمریة متراكبة لمادة بعض الخواص المیكانیكیة والفیزیائیة على الكلفة منخفضة االضافات تاثیر دراسة عبدهللا صباح أورھان مساعد مدرس الخالصة لراتنج البولیستیر الغیر مشبع على الخواص المیكانیكیة والفیزیائیة تأثیر الحشوات منخفضة الكلفة دراسة تمت البحث ھذا في أن مواد التدعیم المستخدمة في ھذا البحث كانت ھي عبارة عن دقائق وزنیة مختلفة. كسور عند عملیا بالدقائق المقواة ، دقائق مطفاءة mgoمحضرة من مواد بسیطة منخفضة الكلفة وھي: دقائق بودرة االطفال الحاویة على اوكسید المغنسیوم وبحجم حبیبي sio2ق مادة الطباشیر الحاویة على اوكسید السیلیكون ، ودقائ caco3الحریق الحاویة كاربونات الكالسیوم 10μm ) لدراسة سلوك البلیان والصالدة والموصلیة الحراریة وامتصاصیة الماء عند ١٥، ١٠%، ٥وبكسور وزنیة (% باستعمال جھاز astm g99-05حیث تم دراسة مقاومة البلیان وفقا للمواصفة اضافتھا الى مادة البولیستر الغیر مشبع. تم قیاس الموصلیة الحراریة بأستخدام قرص . astm d-2240وقیاس الصالدة وفقا للمواصفة المسمار مع القرص الدوار .وقد اظھرت النتائج ان اضافة مواد التدعیم ادت الى زیادة astm d 570لي بینما تم قیاس امتصاصیة الماء وفقا للمواصفة متصاصیة الماء وخفض الموصلیة الحراریة مع زیادة الكسر الوزني لمواد التدعیم وان زیادة الحمل مقاومة البلیان والصالدة وا المسلط خالل اختبار البلیان اى الى زیادة معدل البلى المقاس. واضھرت النتائج ایضاً ان جمیع مواد التدعیم المضافة للبولیستر al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 2 % من دقائق اوكسید المغنسیوم عن ١٥ن افضل نسبة تدعیم كانت ھي اعطت نتائج افضل من عینات البولیستر الغیر مدعم وا اضافتة الى راتنج االبولیستر. 1. introduction polymeric composites have become main part of manufacturing application due to their unique thermal and mechanical properties apart from their easy process ability and low cost. such materials are good candidates to form a special class of engineering tribomaterials due to their unique properties such as wear resistance, impact resistance, corrosion resistance and ease of fabrication. they are utilized in numerous applications including seals, cutting tools, bearings and artificial prosthetic joints. for such applications and others, polymer matrix must with stand high mechanical and tribological loads, so fillers, fibers or particles and added to enhance its properties [1]. polymer composite has been widely used to substitute the conventional metals and ceramics in microelectronic bundling, coating, aerospace, automotive and biomedical applications. this is fundamentally because of their unique strength, lightness, versatility, ease of treatment and low cost. by adding of reinforcement particles, the tribological properties of polymers are in general enhancement [2]. the using of micro particles as a reinforcement material in polymers composite has attracted extra attentions. the very high specific surface area eases creating a mighty amount of interphase in composite and a strong interaction between the particles and the matrix. particles can enhancement the mechanical and physical properties of polymers. some of these particles it will used to reinforce polymers are (sio2, mgo and sic) due to its rigidity and high stability [3]. wear is defining as harm in a solid surface, generally including gradual loss of materials, caused by relative motion between two surfaces. the general kinds of wear are abrasive, fretting, erosion, adhesive and fatigue wear, which are usually seen in practical cases. the ingrained scarcity of polymers could be change successfully by using different special particles [4]. in order to obtain the wear resistance, hardness, water absorption and dielectric strength many researchers modified polymers using different fillers. briscoe et al., notified that the wear rate of high density polyethylene (hdpe) was decreased with the addition of inorganic particles, like cuo and pb3o4 [5]. husam .a. kareem studied the mechanical properties of polyester resin reinforced by nickel powder, the results showed improved material toughness, fracture toughness, compression strength and wear resistance with the increasing of volume fraction and using of (10μm) particle size. the result also showed that the wear rate increase with the increasing of load and temperature [6]. haqi i.gattea, study the effect of magnesium oxide (mgo) with (5 μm) particle size with different weight percentages (5%,15%,25%) was added to conbextra epoxy (ep-10) resin and measured the changing in thermal insulation to this resin. the results show improved thermal insulation of the resin by reduced in thermal conductivity coefficient value after oxide addition , and the value of thermal insulation will increased with increasing of additive percentage of magnesium oxide [7]. amar .j. bader et.al, prepared polyester matrix composites reinforced with short glass fiber and reinforced with glass fiber and al2o3 particles with different weight fractions (3, 5, and 7 wt% al2o3) and study some of mechanical properties to the prepared composites. the results shows the mechanical properties improve with increasing weight fraction [8]. ali al-mosawi, study the mechanical and thermal properties of epoxy (ep-10) resin reinforced by magnesium oxide (mgo) with (5 μm) particle size with different weight percentages (10%,20%,30%) the results show improved thermal insulation of the resin by reduced in thermal conductivity coefficient value and improvement in impact strength, tensile strength, and compression strength after oxide addition [9]. ibtihal et al., studying the effect of 10μm (granite, perlite and caco3) particles used as a reinforcement material for carbon fiber-epoxy composite on wear behavior, and they observed that the adding of particles leads to increase the wear resistance [10]. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 3 in this work a new polymer composite are prepared to investigate the wear properties, hardness, water absorption and thermal conductivity of polyester composite reinforced with low cost materials; baby powder particles including mgo, fire extinguisher particles including caco3 and chalk particles including sio2 with weight fraction of (5%, 10%, 15%)wf%. 2. experimental details 2.1 materials baby powder particles including mgo, fire extinguisher particles including caco3 and chalk particles including sio2 with grain size (10 μm) and weight fraction (5%,10%, and 15%) used as a reinforcement material for polyester resin. unsaturated polyester used as a matrix material produced by (sir). it is in liquid state at room temperature but after adding the hardener will change to solid state. the hardener used to this purpose methyl ethyl keton peroxide with mixing ratio 1:50 hardener to polyester resin at room temperature. the properties of the matrix material shown in table.1. 2.2 specimens preparation hand layup technique was used in this research to prepare the specimens. glass mould used to casting the composite material specimens with dimension of (200, 150, and 10) mm as shown in fig.1. the inner face of the mould was covered with a layer of vaseline to ensure no-adhesion between the polymeric material and the mould. the composite material is prepared by mixing the polyester resin with the hardener in (3:1) ratio at room temperature with a very slow mixing by using glass rod for (15min) until the polymer material will be homogenous, 10μm particulate fillers with 5, 10, and 15 wf% of mgo, sio2 and caco3 added to polyester resin respectively and the mixing continuous until it becomes homogenous, after (2min) the mixing was completed, to prevent air from including inside the specimens we should poured the mixing from one side of the mould and slowly, after 24 hours the solidification process is completed for all moulds and we can released the casts from the moulds. 3. mechanical and physical test 3.1 wear test according to astm g99-05 wear test standard the casts are cut with dimensions as shown in fig.2.to prepared wear test specimens. pin-on-dick test instrument in applied science deportment/university of technology shown in the fig.3 was used to fulfillment the wear test. the effect of different weight fraction and loading, on wear rate was studied according to eq. (1). the steel disc have hardness of (385 hv), speed of (200 r.p.m), and rotating radius of (90 mm). wear tests were carried with sliding time about (900s) and loads ranging from (10-30 n). by using sensitive balance weight with an accuracy of (10 -4 g) the initial weight of all the specimens was measured. after the test ending all the specimens weighed again to calculate the weight loss due to wear. the variance in weight measured before and after tests gives full conception about wear behaviour of the composite specimen. to consider the volume wear rate using eq. (1). wear rate (volume) (cm 3 /m) = !"#!$ %&'( ………………………………………..… (1) where: w1: weight before testing (g), w2: weight after testing (g), ρ: density (g/cm 3 ) and s: sliding distance (m) calculated form eq. (2). s=2πrnt …………………………………………………………………………. (2) n = disc rotational speed, r.p.m, r = the distance from the center of the sample to the center of disc, m, t = time of testing, min. 3.2 hardness test this test is performed by using hardness (shore d) and according to (astm d-2240) standard at room temperature. samples have been cut into a disk with (40mm) and a thickness of (5mm) as al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 4 shown in fig.4 while fig.5 shows hardness device used in this research. for each specimen three hardness measurements were taken and the average hardness is calculated. 3.3 thermal conductivity test the lee's disc, manufactured by griffin and george, ltd., is used to measure thermal conductivity. the apparatus shown in fig.6 consists of four identical copper discs of (40mm) in diameter and (12.25 mm) thickness, one of them includes an electric heater inside denoted by (h). the specimen (s) with the (40 mm) in diameter and (5 mm) thickness as shown in fig.7 is placed between the discs (a) and (b), while the heater (h) is sandwiched between (b) and (c) discs. temperatures of (a), (b) and (c) discs are measured by using three thermometers. thermal conductivity coefficient is then calculated according to eq.(3) & (4). the average of three measurements is taken for each specimen to minimize the possible errors. )* = +,$-./0 1 /23 1 4+,-560/0 1 78 $ ./0 1 /93 1 69/9 1 62/2: ……………….. (3) ; 5<>#<?78 : = -@/0 1 $ a 560 1 " b 6%:/0 1 " $a 6%/cd …………………………..………. (4) 3.4 water absorption disc specimens were prepared with diameter of 40 mm and thickness 5mm in order to obtain the water absorption of the composite material. the specimens weighted before and after immersion in water according to astm d 570 standard as shown in fig.8. the increase in the weight of the specimens was calculated by using equation (5): water absorption= efghi'jkflmn'#opflfghi'jkflmnopflfghi'jkflmn ………………………………... (5) the specimens were immersion for one hundred days in water and it was weighted every ten days. 4. results and discussion 4.1 wear test wear tests were carried out for all specimen prepared from polyester resin and polyester with different weight fractions of reinforcement particles. pin on disc wear test carried out for all the specimens different diagrams are sketched and presenting in fig.9 and fig.10.for different percentage of weight fractions under various test conditions.(weight fraction, and applied load). 4.1.1 the effect of weight fraction: the samples presented a good wear resistance with the increasing in weight fraction of (mgo, caco3, and sio2) particles as shown in fig.9. when we compered the wear resistance results of composite material after adding the reinforced particles with the result of polyester specimen we can observed an increasing about (62.5%, 42%, and 36.75%) in wear resistance respectively. 4.1.2 the effect of applied load: the effect of various normal applied loads on the wear rate was studied for specimens before and after adding the reinforced particles with constant test conditions such as sliding time (900 sec), sliding distance (1507.2m) and the rotating disc speed 200 rpm. from the results we can observed the all the specimens have a decrease in wear resistance with the increasing in normal applied load. this behaviour can be discussed simply when a high load applied to the specimen surface more fraction will happened on it and thus leads to increasing wear rate. the increase in wear rate of composite materials with 15% (mgo, caco3, and sio2) shown in fig.10. the increase recorded appeared by (34.4%, 47.5%, and 62.6%) respectively in wear rate al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 5 with load increasing, but when compared with polyester specimen at the same test conditions its observed increase in wear resistance recorded by (54.2%, 35,3%, and 22%) respectively. 4.2 hardness test hardness test type shore (d) has been carried out on polyester before and after adding the reinforcement particles and the average of three readings in each case taken to obtain higher accuracy results. from fig.11 it can observed that the addition of reinforcement materials leads to increase the hardness of the composite material and the specimens reinforced with 15% mgo have higher hardness than caco3 and sio2 specimens. a similar behavior seen by aseel mahmood et.al when used alumina particles as reinforcement material to polyester resin with (20µm) grain size and 8% weight fraction [11]. 4.3 thermal conductivity the thermal conductivity of prepared composites specimens are measured by lee's disc technique and the experimental results are shown in fig.12 .it can be see that the addition of ceramic fillers (mgo, caco3, and sio2) to polyester resin leads to decrease the thermal conductivity will be high as there results good agreement with result obtained by [9]. and the use of mgo gives the best results as insulation material between the other materials uses in this research. 4.4 water absorption water absorption behaviors of the composite in water immersion against the time in (days) are shown in fig.13, 14, &15. the addition of (mgo, caco3, and sio2) particles leads to increase the water absorption with the increasing in reinforcement material weight fraction%. a similar behavior was seen by n. w. a. razak and a. kalam with the addition of natural fiber or particles the water absorption increase due to the poor interfacial bonding made the composite material may be containing voids and porosity [12]. 5. conclusions 1the wear rate for all the prepared specimens was increased with the increasing in applied load. 2the addition of reinforced particles leads to increase the wear resistance of composite material better than polyester specimen without reinforcement material. 3the mixture of 15% mgo with polyester resin has the highest wear resistance, which is 62.5 % better than that polyester specimen. 4mgopolyester composite has the best wear resistance, hardness, thermal in when compared with caco3-polyester and sio2-polyester composites. 5the addition of (mgo, caco3, and sio2) particles to polyester resin leads to increase hardness and water absorption with the increasing in reinforcement material weight fraction. 6the thermal conductivity decreasing with the increase in reinforcement weight fraction. references [1] pedro v., jorge f., antonio m. and rui l., 2006, tribological behavior of epoxy based composites for rapid tooling, journal of wear, vol.260, pp. 30-39. [2] suresha, b. g. chandramohan, j.n. prakash, v. balusamy and k. sankarayanasamy, 2006, the role of fillers on friction and slide wear characteristics in glass-epoxy composite systems, journal of minerals and materials characterization and engineering, vol.5, no.1. [3] suresha, b. g. chandramohan, j.n. prakash, v. balusamy and k. sankarayanasamy, ”the role of fillers on friction and slide wear characteristics in glass-epoxy composite systems”, journal of minerals and materials characterization and engineering, vol.5, no.1, (2006). al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 6 [4] patel r., kishorekumar b. and gupta n.,2009, effect of filler materials and preprocessing techniques on conduction processes in epoxy-based nanodielectrics, ieee electrical insulation conference, montreal, qc, canada. [5] briscoe, b. j., pogosion, a. k., and tabor, d., 1974, the friction and wear of high density polyethylene; the action of lead oxide and copper oxide fillers, wear, vol.27, pp. 19-34, 1974. [6] husam .a. kareem, "study the mechanical properties of polyester resin reinforced by nickel powder" msc.thesis, mechanical engineering, university of technology, iraq-baghdad, 2008. [7] haqi i.gattea, "effect of particles from magnesium oxide in thermal insulation of conbextra epoxy (ep-10) resin", the iraqi journal for mechanical and material engineering, vol.11, no.4, 2011. [8] amar .j. bader et.al, "effect of alumina particles on the mechanical properties of discontinuous glass fiber reinforced unsaturated polyester composites", al-qadisiyah journal for engineering sciences, vol. 4, no. 1, 2011. [9] ali al-mosawi, "effect of reinforcing by mgo particles on thermal and mechanical characteristics of epoxy resin", the iraqi journal for mechanical and material engineering, vol.11, no.3, 2011. [10] ibtihal a. mahmood, wafa a. soud, orhan s. abdullah 2013, effects of different types of fillers on dry wear characteristics of carbon-epoxy composite, al-khwarizmi engineering journal, vol. 9, no. 2, p.p. 85 -93. [11] aseel mahmood abdullah, ahmed mudhaffer hashim andamar jabar bader, "effect of alumina particles on the mechanical properties of discontinuous glass fiber reinforced unsaturated polyester composites", al-qadisiyah journal for engineering sciences, vol. 4, no. 1, 2011. [12] n. w. a. razak, a. kalam, " effect of opefb size on the mechanical properties and water absorption behaviour of opefb/ppnanoclay/pp hybrid composites", procedia engineering, vol.41, p.p1593 – 1599, 2012. table (1): physical and mechanical properties of polyester resin. young's modulus gpa density g/cm 3 tensile strength gpa specific heat (j/kg.k) flexural strength (mpa) 3 1.09 40 1300 45 fig. 1: the shape of the mould. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 7 fig (2): standard wear test specimen. fig.3: schematic of pin-on-disc wear testing machine. fig.4: hardness test device fig.5: hardness test specimen. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 8 fig.6: thermal conductivity device fig.7: thermal conductivity specimen fig.8: water absorption specimen. fig.9: effect of weight fraction on wear rate of mgo, caco3 and sio2 composites. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 9 fig.10: effect of load on wear rate of mgo, caco3 and sio2 composites. fig.11: effect of weight fraction on hardness of mgo, caco3 and sio2 composites. fig.12: effect of weight fraction on thermal conductivity of mgo, caco3 and sio2 composites. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 10 fig.13: effect of mgo particles on water absorption. fig.14: effect of sio2 particles on water absorption. fig.15: effect of caco3 particles on water absorption. theoretical study of temperature distribution and heat flux variation in turning process al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 922 theoretical study of temperature distribution and heat flux variation in turning process sana j. yaseen mechanical engineering department college of engineering basra university abstract the heat generation during metal cutting processes affects materials properties and the tool wear. knowledge of the ways in which the cutting conditions effect the temperature distribution is essential for the study of thermal effects on tool life. analyses of three-dimensional transient temperature distributions in a metal cutting process using a finite element code the deform 3-d was presented in this paper. the effects of the rake angle, cutting speed, feed rate, tool and workpiece materials on the temperature and heat flux are studied. the results show that increase in cutting speed and feed rate increases the cutting temperature while increasing rake angle reduces the cutting temperature. results indicated that, as cutting speed increased from 103.2 to 250 m/min an increased in temperature equal to 21.9% occurred. with a reduction in rake angle from 5 o to -5 o , temperature increased by 12.3%. as the feed rate increases from 0.16 mm/rev to 0.25mm/rev, the temperature increases in a 13.82%. keywords: finite element simulation; cutting temperature distribution, metal cutting process. chip-tool interface temperature. tool geometries الفيض الحراري في عملية الخراطة اختالف الحرارة و دراسة نظرية لتوزيع درجات ياسين سناء جعفر جامعة البصره -الهندسة كلية -قسم الهندسة الميكانيكية الموجز ان الحرارة المتولدة خالل عملية قطع المعدن تؤثر على كاًل من خواص المعددن وعلدى عمدر اداة ال.طدعع ومعر دة الكيفية التي بها ظروف ال.طع تؤثر على توزيع درجدة الحدرارة ودروريًا لدراادة التداثير الحدرارع علدى عمدر ا داةع deform 3d اصددر محددددةااددتخداف ومددور عوتوزيددع درجددة الحددرارة الثالثددي ا بعدداد بتحليددل تددف ددي اددرا الدرااددة ياددتخدف للتوبددؤ بدرجددة الحددرارة ا وت.اليددة والفددي الحددرارع ددي عمليددة ال.طددعع د رل تدداثير كددل مددن اددرعة ال.طددع زيددادة كددل مددن انمعدددل التيريددة زاويددة الجددرف ومعدددن ا داة علددى درجددة الحددرارة والفددي الحددرارعع بيودد الوتددا درجدة الحدرارة تدزداد ارعة ال.طع ومعدل التيرية تزيد مدن درجدة حرارةال.طدع بيومدا زيدادة زاويدة الجدرف ت.لدل موهداع ف/دقي.دددة وعوددددما يدددزداد معددددل التيريدددة مدددن .95الدددى 9ع3..مدددن ادددرعة ال.طدددع% عوددددما تدددزداد 2ع.9بمعددددل 5-الددى 5و عودددما ت.ددل زاويددة الجددرف مددن 39ع3.%مددف/دورة تددزداد درجددة الحددرارة بمعدددل 95ع.الددى 0.ع. ع3ع9.تصل الزيادة ي درجة الحرارة الى % sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 nomenclature greek symbol heat capacity (w/m k) cp thermal diffusivity (m 2 /s) α heat transfer coefficient(w/m 2 k) h metal density (kg/m 3 ) ρ thermal conductivity of metal (w/m k) kt frictional stress  heat flux (w/m 2 ) q = coefficient of friction μ temperature (k) t subscript time (s) t medium ∞ stress (pa)  normal n introduction during a cutting process, the mechanical energy resulting from the plastic deformation developed at the primary shear plane and at the chip–tool interface is converted into heat (lazard, 2005). studies have shown that the chip and the environment dissipate a great deal of this heat while the reminiscent is conducted both into the workpiece and into the cutting tool. however, this small quantity of heat conducted into the tool (8–10% of the total heat rate) is enough to create high temperatures near the cutting edges, which in some cases can reach the level of 1100 ◦ c (carvalhho et al, 2005). it is clear that the determination of the exact temperature rise in the tool–chip interface has been recognized as an important factor in achieving the best cutting performance. that is the reason why several researchers have become interested in determining the temperature histories on the rake face of cutting tools. many of temperature measurement techniques have been developed over the years, to determine the temperature distribution of the tool chip interface, rake face, cutting tool, workpiece, chip surface, etc.( grzesik, 2006). the methods commonly adopted by the researchers are the metallographic method, i.e., micro hardness and microstructure analysis, embedded and tool chip thermocouples, thermal radiation, thermo sensitive paints, powders of constant melting point (chung, 2007), thermocouple techniques. thermocouple-insert techniques, (herchang et al, 1998), hybrid technique and heat source methods. etc. (shijun et al, 2008). however, direct measurements of temperatures at the tool–chip–workpiece interfaces are very difficult due to the cutting movement and the small contact areas involved (carvalhho et al, 2005). due to these experimental difficulties many analytical and numerical methods solution have been employed to predict machining temperature the moving heat source method, the image sources method, the finite difference method, the semi-analytical methods and the finite element method. a review of the most common experimental techniques for temperature measurement in metal cutting processes reveals that these techniques can be classified as: direct conduction, indirect radiation, and metallographic. (haci et al, 2005) measured the cutting forces and averaged tool tip temperature in turning aisi 1040 steel hardened at hrc 40. the effects of feed rates and cutting tool geometry, approaching angles and rake angles on cutting forces were evaluated. during the tests, the depth of cut and cutting speed were kept constant and each test was conducted with a sharp uncoated tool insert. the cutting force components and temperature variations on tool face (in secondary shear zone) were determined. in this way, the essential information about the validity of selected values was obtained. it was found that the average deviation between calculated and the measured temperature was 42% for the same experiments. (abhang et al, 2010) studied average chip-tool interface temperatures experimentally using the tool work thermocouple technique. based on the parametric study, a first-order and second -order empirical models of the chip-tool interface temperatures has been developed for turning of en-31 steel alloy with tungsten carbide tools. the results are analyzed statistically and graphically. the metal cutting parameters considered are cutting speed, feed rate, depth of cut and tool nose radius. the results show that when cutting speed increases from 39m/min to 189m/min the increase in temperature in cutting zone of 174%. as the feed rate increases from 0.06mm/rev to 0.15mm/rev, the temperature increases in 38.57%. (abukhshim et al, 2005 a) have also studied the heat partition using an uncoated cemented carbidetheoretical study of temperature distribution and heat flux variation in turning process 033 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 cutting tool in high speed turning of aisi/sae-4140 alloy steel. experimental results are presented of temperature measurements on the tool rake face during orthogonal cutting at cutting speeds ranging between 200 and 1200 m/min. these measured temperatures are compared with temperature fields in the cutting tool obtained from a finite element transient thermal analysis. it is shown that the tool–chip contact area, and hence the proportion of the secondary heat source conducting into the tool, changes significantly with cutting speed; it decreases with the cutting speed in the conventional and the transition regions but increases in the hsm region approaching 65% at 1200 m/min. (rech et al, 2005) analyzed the effective heat flux transmitted into the tool during the machining operation on 27mncr5 steel of the workpiece. the temperature is measured by the thermocouple fixed to the insert holder. the inverse heat conduction problem is solved so as to estimate the heat flux transmitted into the tool for the various tested coatings however, direct measurements of temperatures at the tool–chip–workpiece interfaces are very difficult due to the cutting movement and the small contact areas involved and may not give any accurate estimate of the temperatures (abukhshim et al, 2005 b). due to these experimental difficulties, metal cutting researchers have developed many modeling techniques including analytical techniques slip line solutions, empirical approaches, the boundary-element method of heat conduction and finite element techniques (marcio et al, 1997). (pradip et al, 2005) carried out a parametric study to investigate the effect of operating conditions on the thermal characteristics of the tool, chip and the workpiece. the heat conduction model would be used to predict the temperature distribution in the tool, chip and workpiece. the workpiece material that was considered free machining steel and the cutting tool-tip material was tungsten carbide. additionally, the model takes into account the geometry of the work-piece/chip/tool, convective losses, and the temperature dependent thermo-physical properties of the materials. the major operating parameters that have significant effect on the heat generation and distribution temperatures are, cutting speed, feed rate and depth of cut. it can be noticed that the maximum temperature in the tool increased from 709.36 k to 1320 k as cutting speed is increased from 29.6 m/min to 155.4 m/min. a series of numerical simulations had been done by (hong et al, 2005), to investigate the effect of machining parameters (cutting speed, depth of cut and tool-tip radius) on the finish hard turning of aisi h13 steel using finite element model. the results obtained from this research indicated that the maximum workpiece temperature increases from around 646 to 922.78 ◦ c, the maximum tool temperature increases from 147.6 ◦ c to 406.78 ◦ c when the cutting speed increases from 150 to 750 m/min. the maximum workpiece temperature increases from around 804.9 to 934.58 ◦ c, the maximum tool temperature increases from 352.2 to 385.28 ◦ c. when the depth of cut increased from 5 to 20 µm, the maximum workpiece temperature increased from 876.9 to 1081.98 ◦ c. (jaharah et al, 2009) have predicted 3d finite element modeling using deform software on the finish hard turning of aisi 1045 steel. the effect of cutting tool geometries on the effective stress and temperature were studied. the tool geometries studied were various rake angle (α ) and clearance angle ( β ) in the range of -5° to 5°, and 5° to 9° for α and β respectively. the effect of various machining parameters of cutting speed (100m/min to 300m/min) and feed rate (0.15mm/rev to 0.35mm/rev) were also investigated. nose radius (rn) and depth of cut were kept constant at 0.4mm and 0.18mm respectively. simulation results for negative rake angle shows minimum temperature of 605°c was obtained using rake angle of -5° and clearance angle of 5° with cutting speed of 100m/min and feed rate of 0.15mm/rev. the results show that the effective cutting temperature on the cutting edge were between 605°c and 2080°c. finite element analyses were performed by (bareggi et al, 2007) using software deform 3d. an aisi 1020 steel workpiece (1.5mm of length) was modeled and tungsten carbide (wc) using as a work-piece. in order to get the correct value of steady state temperature in the insert, a lower heat capacity value has been used. the cutting conditions using are cutting speed: 270m/min, feed: 0.06mm/rev and depth of cut: 0.5mm. and the insert configuration: rake angle = 0°, nose radius = sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 0.2mm, investigations indicate that there is a reduction in temperature when the high velocity air jet is applied during metal cutting. under severe conditions, the temperatures at tool–chip interface and around the cutting edge can be critically high, resulting in an excessive tool wear or even a premature tool failure. therefore, it is necessary to develop an accurate cutting process simulation to identify optimum cutting conditions in terms of tool material and tool geometry in order to improve cutting process. the tool–workpiece interface region can be shown in fig. (1) (bonnet et al, 2008). in the present study temperature distribution and heat flux variation in turning process studied by varying the cutting speed, feed rate, tool geometries of the rake angle and tool materials. theoretical fundamentals in this section, the heat conduction model is be used to predict the temperature and heat flux distribution in the tool and work piece interface (see fig. (2)). the unsteady state three-dimensional heat-conduction equation, can be written as (molinari et al, 2005): t t k tzyxq z t y t x t tt             1),,,( 2 2 2 2 2 2 (1a) where kt is the thermal conductivity, t the temperature, ∂t/∂η the derivative of temperature, αt the thermal diffusivity coefficient, ρ the density, cp the heat capacity, t the time and t∞ the medium temperature. this equation is subjected to the following boundary conditions (raja, 2008): in the regions exposed to the environment: )(      tth n t k i (1b) analytical model for the heat transfer calculations, the following assumptions are made : i) the contact between the tool and the chip is thermally perfect. hence a very large value of the interface heat transfer coefficient (h is used and it is fixed to 1000 kw/m 9 ii) the boundaries that are sufficiently away from the cutting zone remain at the room temperature (t∞=20 ºc ( iii) the chip and the tool loss heat due to heat convection on the free surfaces on the work piece iv) heat losses due to radiation is very small and it is neglected. at the tool–work piece interfaces: )('' tq n t k     (1c) initial condition:   tozyxt ),,,( (1d) where heat flux could be calculated from (syed et al, 2009). )()(''   tthtq (2) theoretical study of temperature distribution and heat flux variation in turning process 030 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 where h is the heat transfer coefficient in w/m²/k. cutting tools, workpiece, and cutting parameters a lagrangian finite element code was applied to construct a thermo mechanical finite element model of the plane-strain orthogonal metal cutting with a continuous chip formation produced by plane-faced uncoated carbide tools. the work piece is modeled as thermo-elasto–plastic with material of choice aisi 1045, 1030, 1025 & 316h. the work piece is fixed in all directions, and the tool is considered to be rigid and moving towards the work piece at the cutting speed (νc). for this model the tool materials are 15%co, coating tic and wc. according to the fem model, the cutting parameters used are the feed rate (f) which is assigned to four different levels varying from 0.16 to 0.25 mm/rev. the rake angle (γ) is changed to 5,0 and -5. the cutting speed (νc) changes from 100 m/min to 250 m/min and depth of cut (d) was kept constant at 2 mm. the shapes of tool used in this work are arranged in table 1, while the temperature dependent thermo-physical properties (modulus of elasticity, thermal conductivity, and heat capacity) of the tool and work piece are given in tables 2 & 3 respectively (user's manual, 2007). finite element modeling in the present work, a 3d analytical simulation was performed for modeling the cutting process using deform-3d finite element code. the automatic generation of the elements was not adopted since this would cause a uniform meshing and the result will not be that accurate, so the very fine mesh density is defined at the tip of the tool and at the cutting zone to obtain fine process output distributions. the work piece has a size of 4.5×2.5×0.8mm, which was initially meshed by means of 1401 iso-parametric quadrilateral elements while the tool, modeled as rigid, was meshed into 11025 elements. the deformation of the material was described by using a reliable model proposed by oxley law. the friction modeling plays a significant role on the results such as cutting forces; temperature and tool wear in the metal cutting simulation. in the early metal cutting simulation, the simple coulomb friction model was used to the whole contact zone with a constant friction, coefficient model (cenk, 2009). n   (3) where, τ is the frictional stress, σn the normal stress and μ the coefficient of friction with value of 0.5. the initial geometry and mesh are presented in fig. 3 (a), the heat transfer is allowed on the tool-work piece contact area. results and discussion in this section, the heat conduction model will be used to predict the temperature and heat flux distribution in the tool and work piece interface region. verification of the constructed model to validate the predicted results obtained from the present constructed finite element model, the simulation results were validated by comparing them to the appropriate results provided in ref. (grzesik et al, 2005) cutting parameters in this reference are: cutting speed νc =103.2 m/min, feed rate f =0.16 mm/rev, the work material is aisi 1045steel and depth of cut =2mm. figure 4 shows the comparison between the present work and previous works. figure 4 (b) represent the work piece while figure 4 (c) represent the tool. the percent of error in temperature measurement is about 0.88% in the work piece side and 0.63% in the tool side. temperature distribution through the work piece and tool face (a) temperature distribution through the work piece sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 it should be noticed, as in figure 5 that the maximum temperature value through the work piece progresses with the tool movement. this figure is drawn for the contact region at different times, when the tool progress on the work piece the contact region has a maximum temperature. (b) temperature distribution through the tool face the temperature distribution in different nodes on the tool was shown in figure 6. the maximum node temperature is obtained exactly in the middle contact between the work piece and tool. the highest temperature of the tool surface, about 470 o c, was located at a distance nearby the tool tip, this was due to high heat generation in the contact region between tool and work piece. as the node is far of the cutting edge, it has temperature lower than the nearest node. effect of cutting conditions on tool-work piece interface temperature the temperature in the interface would be affected by the cutting speed, the feed rate and the tool geometry. it was also depended on the physical properties of the work piece and tool materials. (a) effect of cutting speed on temperature distribution figure 7 (a) was performed at different cutting speeds and at f=0.16mm/rev, γ =-5 o , and at the same distance from the cutting edge (x=1.8643mm). it indicated from that figure at the speed of 103.2 m/min, the maximum temperature is 548 o c, while at the speed of 250 m/min maximum temperature is 720 o c. in the cutting process when high cutting speed was used maximum stresses are obtained, and these stresses are more concentrated in the tool tip which may cause plastic deformation of tool edge. high temperatures are generated in the contact area because of plastic deformation of work piece material and friction along the tool/chip interface; this induces an increase in temperature in the cutting zone. when the cutting speed increases from 103.2 m/min to 250m/min, the increase in temperature was equal to 21.9%, which indicated that the tool-work piece interface temperature is closely connected to the cutting speed. on the other side, figure 7 (b) is drawn for temperature versus time at three values of the cutting speed, it is indicated from that figure the maximum temperature is about (976 o c at interval of time=0.001093 ms) for v=200m/min, (tmax=759.2 o c at t=0.001447 ms) for v=150 m/min and (tmax=659 o c at t=0.00212 ms) for v=103.2 m/min, with increasing in the cutting speed, maximum temperature increased and the time in which high temperature occurred reduced. when high value of cutting speed used in the cutting process, this means increase the power to remove more material in a shorter time. power consumed in metal cutting was largely converted into heat, which leads to increase the heat generation near the cutting edge of the tool, so high value of temperature obtained. (b) effect of feed rate on temperature distribution and heat flux the distribution of temperature and heat flux along the interface predicted for different feed rate is shown in figure 8. as the feed rate increases, the section of chip increases and consequently friction increases, this lead to increase cutting forces, especially in thrust direction. it is observed that the region of high stresses in the thrust direction turns inward as the feed increases, which may result in the increase in temperatures generated, so the temperature at interface increases. as the feed rate increases from 0.16 mm/rev to 0.25mm/rev, the temperature increases in a 13.82%. the effect of feed rate on the heat flux can be shown in figure 8 (b), it was clear from that figure when the feed rate increased high temperature generated due to cutting large pieces from the metal in one revolution, which transmitted as a heat flux between tool and work piece. (c) effect of tool material on temperature distribution and heat flux figure 9 presented the values of temperature figure 9 (a) and heat flux figure 9 (b) for different tool materials. from these two figures, it is easy to understand that the tic coating induces the lowest temperature rise and heat flux due to the fact that coating tool leading to decrease of the tool–work piece contact area, decrease of the thickness of the secondary shear zone and of the theoretical study of temperature distribution and heat flux variation in turning process 033 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 temperature at this interface, which lead to a decrease of the heat flux transmitted to the cutting tool, since the flux transmitted depends on the contact area and the heat created at this interface (heat flux density). the uncoated tool induces the highest heat flux in the tool (after 0.002 ms of cutting time: heat flux = 900 w), while the tic coated tool induces the lowest heat fluxes (600w). the wc has an intermediate behavior (700 w). these results clearly show that the use of tic-coated tools generally reduces the heat partition into the cutting tool. lowest temperature distribution can be observed with coated tic tool, and higher temperature distribution with 15% co due to the lower effective thermal conductivity for tic and highest thermal conductivity for 15% co. (d) effect of work piece material on temperature distribution and heat flux four curves have been plotted for different materials (these materials were selected because of their suitability and widely used in the model by previous researcher) as shown in figure 10 (a) and (b). the temperature dependent properties should be considered when calculating the cutting temperature, so the thermal properties of the work piece such as the thermal conductivity and specific heat as functions of (t) are shown in table 3 (user's manual, 2007). from that table it was clear that the heat capacity for the four materials equal, so they behavior depending on thermal conductivity. for the same range of temperature aisi1025 and aisi1030 have the same behavior of thermal conductivity, while aisi1045 has a larger value at a lower temperature, aisi 316h has a lower thermal conductivity than other materials. thermal conductivity of these four materials was depending on temperature and effect on the temperature distribution in the contact region, so the curves oscillated and overlap with each other depending on variation of their thermal properties. (e) effect of rake angle on temperature distribution and heat flux in this part of the study, effect of rake angle on the distribution of temperature in both work piece and tool was analyzed. the rake angle is one of the most important parameters, which determine the tool and work piece contact area. there is generally an optimum value for the rake angle, increasing of the rake angle over its optimum value has a negative effect on the tool performance and accelerates the tool wear. in this analysis, three different rake angles (-5º,0º, 5º) are used . the effect of different rake angles on temperature distribution was shown in figure 12. maximum temperature is reaches to 656 o c, 605 o c and 593 o c when rake angle is equal to -5º, 0º and 5º respectively. it can be noticed with a reduction in the rake angle, promotes a longer contact length and hence a larger contact area with more heat conducting into the tool, therefore high heat will be generated, so the temperature increases when the negative rake angle is used. on the other side by increasing the positive rake angle (higher shear angle produces), the cutting forces were decreased; the reason is that the tool can plunge into the work piece easily. in this study for the same time of simulation (t=0.0015 ms), the temperature increase by 12.3% when rake angle reduce from +5 o to -5 o . (f) effect of tool shape on temperature distribution and heat flux geometry is found to affect local steady-state temperatures in the cutting tool. the tool geometry is designed to cut various work piece metals by forming chips in a smooth way, while also providing a strong cutting edge. many index able inserts have combinations of chip breaking functions to cope with light cuts at the corner and larger depths of cut along the cutting edge. at one end, insert geometry for finishing will have an area comprising smaller feeds and depths while at the other end, a rough-turning geometry will have a large feed and depth values. the finishing insert uses the geometry at the corner of the insert while the roughing one uses a relatively long part of the main cutting edge. the tool shape details are arranged in table 2 (user's manual, 2007), these tools have the same noise radius and height, the different between these tools is the shape. the effect of the shape of tool on temperature and heat flux behavior drawn in figure 13, at the beginning of cutting process tnma has the largest value of temperature than the other shapes, when cutting process progress vnma has the large value of temperature and tnma has the lowest value. at the ending of cutting tnma has the large value of maximum temperature than the other shapes of tool, sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 it was clear that these curves are overlap with one another in such a way that depending on the contact area in the time of cutting, and on the approaching angle forming between tool and work piece. conclusions this paper presents approaches for modeling the prediction of the temperature distribution and heat flux at the interface with the commercial package deform 3d. a parametric study was carried out to predict quantitatively the temperature level and heat flux at the interface with cutting speed, feed rate, rake angle, tool geometry, tool material and work piece materials. the main conclusions, deduced from the present work, can be summarized as follows: 1. the maximum temperature value through the work piece progresses with the tool movement, maximum value of temperature obtained at the contact region between the tool and work piece during the cutting process. 2. interface temperature is closely connected to cutting speed. with increase of cutting speed, an increase occurs in the interface temperature. when the cutting speed increases from 103.2 m/min to 250m/min, the increase in temperature was equal to 21.9% 3. interface temperature also increased with the feed rate, as the feed rate increased from 0.16 mm/rev to 0.25mm/rev, the temperature increased in a 13.82%. however, the cutting speed appeared to have more pronounced effect on the cutting temperatures than the feed rate. 4. rake angle have a considerable effect on cutting temperature on the interface. the temperature increased by 12.3% when rake angle reduce from +5 o to -5 o . refrences abhang,l.b.hameedullah, m.2010.chip-tool interface temperature prediction model for turning process. international journal of engineering science and technology, vol.2(4), pp.382-393. abukhshim, n.a. mativenga, p.t. sheikh, m.a.2005 a. investigation of heat partition in high speed turning of high strength alloy steel. international journal of machine tools & manufacture,vol. 45, pp.1687–1695. abukhshim, n.a. mativenga,p.t. sheikh, m.a. 2005 b. heat generation and temperature prediction in metal cutting. international journal of machine tools & manufacture, vol. 46, pp.782– 800. bareggi, a. o’donnell, g,e. torrance, a.2007. modelling thermal effects in machining by finite element methods. proceedings of the 24 th international manufacturing conference, vol.1, pp.263272. bonnet, c. valiorgue, f. rech, j. claudin, c.2008. identification of a friction model—application to the context of dry cutting ofan aisi 316l austenitic stainless steel with a tin coated carbide tool. international journal of machine tools & manufacture, no.48, pp.1211-1223. carvalho,s.r.limae,s.m. machado,a.r.guimaraes.2005. temperature determination at the chip– tool interface using an inverse thermal model considering the tool and tool holdr. journal of materials processing technology, no.179, pp.97–104. cenk, k.2009. modelling and simulation of metal cutting by finite element method. thesis, graduate school engineering and sciences, 12. theoretical study of temperature distribution and heat flux variation in turning process 033 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 chang, s. 2007. prediction of the cutting temperatures of stainless steel with chamfered main cutting edge tools. journal of materials processing technology, vol.190, pp.332–341. grzesik,w.c. 2006. composite layer-based analytical models for tool–chip interface temperatures in machining medium carbon steels with multi-layer coated cutting tools. journal of materials processing technology, vol. 176.pp.102–110,. grzesik, w. bartoszuk, m. nieslony, p.2005. finite element modeling of temperature distribution in the cutting zone in turning processes with differently coated tools. journal of materials processing technology, vol.164, no.165, pp.1204–1211. haci, s. faruk,u. suleyman,y. 2006. investigation of the effect of rake angle and pproaching angle on main cutting force and tool tip temperature. international journal of machine tools & manufacture , no.46, pp.132–141. herchang,a. wen,j.y. 1998. heat transfer and life of metal cutting tools in turning. int. j. hear mass transfer. vol. 41, no. 3, pp. 61s.523. hong,y. hua, j. shivpuri, r.2005. numerical simulation of finish hard turning for aisi h13 die steel. science and technology of advanced materials, no.6, pp.540–547. jaharah,a.g.wahid,s.w.chehassan,c.h. nuawi,m.z. mohd,n.a.2009.the effect of uncoated carbide tool geometries in turning aisi 1045 using finite element analysis. european journal of scientific research, issn 1450-216x ,vol.28,no.2, pp.271-277. lazard,m. corvisier,p.2005.inverse method for transient temperature estimation during machining. 5th international conference on inverse problems in engineering. theory and practice cambridge, uk, 11-15 th ,7,pp.1-7. lazard,m.remy,b.2008. heat flux and temperature estimation during cutting process through regularization technique. 5 th european thermal sciences conference, the netherlands, pp.1-8. marcio,b.s. james,w.1999. cutting temperature prediction and measurement methods a review. journal of materials processing technology, vol. 88, pp.195–202. molinari, a. moufki, a. 2005. a new thermo mechanical model of cutting applied to turning operations. part i. theory, international journal of machine tools & manufacture,vol. 45,pp.166– 180. o¨zel,t. sima,m. srivastava,a.k. kaftanoglu,b.2010. investigations on the effects of multi-layered coated inserts in machining ti6al4v alloy with experiments and finite element simulations. cirp annals manufacturing technology, no.59, pp.77–82. pradip,m. jayaramachandran, r. ganesan, s.2005. finite element analysis of temperature rise in metal cutting processes. applied thermal engineering, vol. 25, pp.2152–2168. raja, k. 2009. cutting tool temperatures in interrupted cutting, the effect of feed-direction modulation. journal of manufacturing processes, 28 may. sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 ranga,k. zhen,b. 2001.thermal modeling of the metal cutting process. partii temperature rise distribution due to frictional heat source at the tool chip interface. international journal of mechanical sciences, vol43, pp.57-88. rech,j. kusiak,a.battaglia, j.l. 2004.tribological and thermal functions of cutting tool coatings. surface & coatings technology, no.186, pp. 364– 371. sarat,b.s.2005. a mixed solution for the three-dimensional temperature distribution in turning inserts using finite and boundary element techniques. journal of materials processing technology,vol.166, pp.98–106. shijun,z. zhanqiang,l. 2008. an analytical model for transient temperature distributions in coated carbide cutting tools. international communications in heat and mass transfer, vol. 35, pp 1311– 1315. syed,a.i. paul,t.m. mohammad,a.s. 2009. an investigation study of the interface heat transfer coefficient for femodelling of high speed machining. ned university journal of research,vol.4,no.1. user's manual of deform-3d version 6.1. 2007. 18 th oct. table 1 tool different shape using (user's manual, 2007). theoretical study of temperature distribution and heat flux variation in turning process 033 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 table 2 mechanical and thermal properties of the tool (user's manual, 2007). table 3 thermal properties of work piece materials (user's manual, 2007). heat capacity j/kgk thermal conductivity w/mk young’s modulus gpa material cp=75.62×t 2 332.27×t+238 k=7×10 -6 ×t 2 0.0184×t+44.57 y=-0.02×t 2 65.3×t+2122646 aisi 1045 cp=15.2×t 2 101×t+477.25 k=8×10 -6 ×t 2 0.0369×t+53.7 same as aisi 1045 aisi 1030 same as aisi 1030 k=8×10 -6 ×t 2 0.036×t+53.7 same as aisi 1045 aisi 1025 same as aisi 1030 k=-3×10 5 ×t 2 +0.029×t+14.36 y=-0.037×t 2 79×t+212334 aisi 316h figure 1 heat sources during cutting (bonnet et al, 2008) figure 2 simulation model of the turning process used sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 figure 3 the unreformed mesh of both the tool and the work piece. a) before the simulation. b) after deformation. figure 4 comparison between computed values of the interface temperature and (grzesik et al, 2005) (b) work piece (c) the tool. figure 5 maximum temperature with the tool progress. theoretical study of temperature distribution and heat flux variation in turning process 033 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 figure 6 temperature history of tool nodes.(a) position of nodes on tool face. (b) temperature history of tool face nodes. sana j. yaseen al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 033 theoretical study of temperature distribution and heat flux variation in turning process 030 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 299-313, year 2012 template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 171 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. effect of ultrasonic peening technique on fatigue life of 6061-t6 aluminum alloy shaker s. hassan, mechanical engineering dept., university of technology, baghdad. iraq. email: shaker_sakran1952_1@yahoo.com mohsin n. hamzah, mechanical engineering dept., university of technology, baghdad. iraq. email: 20066@uotechnology.edu.iq raad m. abed, ministry of higher education and scientific research, baghdad. iraq. email: raad1232002@yahoo.com received on 23 january 2017 accepted on 13 march 2017 abstract: the ultrasonic peening technique (up) is one of the innovative and hopeful methods for fatigue life enhancement and upgrading of welded structures and components. the fatigue testing of sheet specimens for 6061-t6 aluminum alloy, demonstrated that the up is an effective change treatment to mechanical properties as judged against unpeened specimens. s-n curve and the fatigue fracture mechanism were scrutinized in detail. the most important results revealed the fatigue life of specimens improved due to the surface hardening. residual compressive stresses were created by up and increased the fatigue life and strength. this paper scrutinized the potential use of ultrasonic waves on the surface of 6061-t6 aluminum alloy. this can be exhibited as a factor of safety due to ultrasonic, reach to 1.42 when estimate the number of cycles fatigue based on amount of applied stress at 0.3 u. keywords: ultrasonic peening technique, fatigue test, 6061-t6 aluminum alloy 1. introduction over the past decade, there has been a developing enthusiasm for quickening the advancement and employment of novel substances in vital railroads, cars, and pipelines frameworks. a vital branch of this exertion includes significant expansion of fatigue life forecast capacities. one of the hopeful processing by means of the high power ultrasonic for manufacturing applications is the ultrasonic peening technique (up) of elements and welded sections. in most industrial appliances, the up is known as ultrasonic impact technique (uip). the ultrasonic peening generates a sum of valuable effects in alloys and substances. most an important along with these effects is escalating the resistance of substances to failures, such as fatigue life span, wear and stress corrosion cracking. mailto:shaker_sakran1952_1@yahoo.com mailto:20066@uotechnology.edu.iq mailto:raad1232002@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 172 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. in common, the essential up components, as shown in figure (1), could be utilized for handling of weld toe and bigger outside regions if needed (yuri and jacob 1). numerous investigational researches on the cause of up on the fatigue strength have been carried out in the condition that up was done under no load and lower stresses ( kazeno and sekiguchi, tominaga et. al., 2, 3 ). this method was primary discovered in the 1950s and the early effort through 1980 was assessed by (le 4). figure 1. graphic sight of transducer designed for ultrasonic peened samples. more recently, ( herwig 5 ) has put forward a comprehensive survey of enhancements in the mid ten years back, particularly with respect to the utilization of ultrasonic fatigue for fatigue crack growth threshold studies. however in latest years, study endeavor has been focused mainly in japan and europe, where the method is benefit from substantial utilize there as a instrument for very extended fatigue life forecast ( stefanie and herwig, stefanie 6, 7 ). various studies have been carried out viewing that the fatigue behavior of many important structural materials systems, comprising aluminum, nickel titanium and based alloys can be determined efficiently by ultrasonic fatigue technique. a weld toe pattern could be treated by means of ultrasonic peening which it is in fact affected to plane surface of the forged spring or gear of the manufactured components. it has been verified that eliminating tensile residual stress from weld toes without doubt improved the fatigue strength ( mehmet 8 ). in scientific literatures, apparatus are identified with numerous given names: ultrasonic impact treatment, ultrasonic .peening, ultrasonic peening treatment (lets global, zhao 9, 10 ) , high-frequency .impact treatment ( sonats 11), pneumatic impact treatment ( pitec 12 ), and ultrasonic needle peening ( sonats, bousseau and millot, 13, 14 ). in this research, the aim of the study described is to check up the prospective utilization of ultrasonic waves on the surface of 6061-t6 aluminum alloy. the ultrasonic transducers which can be utilized for up, consist of two general sorts: magnetostrictive and piezoelectric. together achieve a similar errand of changing over varying electrical energy to vibratory mechanical energy yet do it in a dissimilar manner (figure 1). in magnetostrictive transducer the substituting electrical energy from the ultrasonic generator is initially changed over into an alternating magnetic field using a wire coil. at the ultrasonic frequency in magnetostrictive substance, the alternating magnetic field could be utilized to initiate mechanical vibrations .for the most part, the magnetostrictive transducers are less proficient than the piezoelectric ones. this is expected essentially to the way that the magnetostrictive al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 173 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. transducer needs a double energy change from electrical to magnetic also, after from magnetic to mechanical. this lead to missing a several effectiveness in every transformation. magnetic hysteresis impacts likewise reduce the proficiency of the magnetostrictive transducer. also, the magnetostrictive transducer for up necessities required water-cooling. the apparatus for this situation is moderately substantial and costly. piezoelectric transducers change over the alternating electrical energy straightforwardly toward mechanical energy throughout the piezoelectric impact. a piezoelectric transducers physically powerful incorporated in the recent years, more effective and exceedingly steady ceramic piezoelectric substances, which be able to work under the temperature and stress situation. piezoelectric transducers are dependable today and can lessen the energy.costs for function by as much as.60%. because of the elevated energy effectiveness of piezoelectric transducers, .the outcome in fatigue life enhancement is virtually the identical by utilizing of the magnetostrictive transducer through power utilization of 1000 watts and enhanced piezoceramic transducers by power utilization of just 250 to 500 watts. so, the device which used in this work is piezoelectric transducer. 2. experimental work the ultrasonic treatment was completed according to the manufacturer’s principle. the ultrasonic producer was 20 khz at the utilization. the ultrasonic peening device has a trade name: hc, and made in china with numeral model: hc-s-1. for typical states of application, the indenters consist of four 3 mm diameter pin, fitted in a solitary holder as shown in figure (2). figure2. ultrasonic peening device type hc-s-1 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 174 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. short passes was used for the treatment. one passes over one surface of specimen with instrument velocity of 0.25 m/min were completed at an exacting place to make sure a smooth consistent contour contact. the concentration power of the handling was controlled via setting the intensity of output power variety on regular box with 500w maximum power. appropriate process of the apparatus was ensured through the electronic screen on the regular box, which demonstrated the working amplitude of the indenters, and was kept up at 30-35 μm. the sufficiency of the treatment was guaranteed by adopting the working systems consistently and via visual examination of the treated surface. perfect treated specimen showed a glossy regular groove on surface figure (3). indications of extreme cold working and plastic deformation with creation of material flake were obvious. figure 3. treated specimen by ultrasonic peening at the narrow area. the geometry of fatigue workpiece and the dimensions are shown in figure 4, and the chemical composition and mechanical properties of alalloy 6061-t6 are given in table (1) and (2), respectively. the tests were performed at the sierbaghdad (state company for inspection and engineering rehabilitation). figure 4. geometry of fatigue specimen (dimensions are in millimeter) [astm]. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 175 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (1). chemical composition of alalloy 6061-t6, wt %, [astm]. % zinc %titanium %silicon %manganese standard ≤ 0.25 ≤ 0.15 0.4-0.8 ≥ 0.15 measured 0.16 0.024 0.55 0.07 % iron % copper % chromium % magnesium standard ≤ 0.7 0.15–0.4 0.04 0.35 0.8 – 1.2 measured 0.35 0.23 0.065 1.12 table (2). mechanical properties of the specimens of al alloy 6061-t6. property experimentali standard ultimate stress strength 348 mpa 340 mpa yield stress strength 306 mpa 296 mpa fatigue strength 100 mpa 95 mpa modulus of elasticity 71 gpa 69 gpa elongations % 11.9 11 vickers hardness test the vickers hardness examination approach comprises of indenting the check material with a diamond indenter, as a correct pyramid with a quadrangle base with an edge of 136 degrees between opposite confronts subjected to a load of 30 kgf. the applied load is typically connected for 10 to.15 seconds. the double diagonals of the breach left in the surface of the material subsequent to expulsion of the load are calculated utilizing a microscope and their normal computed. the zone of the inclining surface of the space is determined. the vickers hardness is the remainder obtained by separating the kgf load by the square area of space. and the result come from the vickers hardness test for ultrasonic peening and unpeened specimens was 95.89hv30 and 93.78hv30, respectively. mechanical testing the fatigue tests device which is utilized in this study shown in figure 5. the experiments were carried out at constant amplitude fatigue loading in bending. the utilized frequency was 23.33 hz at the experiments with changeable loads. the tests were carried out by using avery 7305 bending machine manufactured in england. all experiments were controlled and checked by strain gages fixed on the external face of the specimens. the specimens were from time to time reviewed for fatigue cracks, visually with the aid of a amplifying glass. tests were ceased when a fatigue crack propagate throughout the surface of the specimens. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 176 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 5. fatigue bending machine type (avery 7305) 3. results and discussion s-n schemes fatigue life against the average documented nominal stress variety data for the handled specimens and unpeened specimens are schemed to obtain as s-n curve. these curves consist of five level of stress with three recordings for each level. experiments outcome reveal that the treated specimen via up obtained considerable improvement in life and strength. the fatigue results of 15 specimens for five level of stresses, each level examined 3 specimen, the results were obtained at room temperature (rt) and stress ratio (r= -1) for two cases, so the total is 30 specimens. the first case comprised specimens examined as received alloy, while in the second case, the specimens were tested under fatigue ultrasonic peening interaction, as illustrated in figure (6). it is apparent that the ultrasonic peening improved the fatigue life of alloy and extend the high cycle fatigue life (hcf). nƒ (number of cycles to failure x10 3 ) figure 6. s-n curves at constant load for unpeened and ultrasonic peened samples. stress at failure, бƒ (mpa) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 177 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. in circumstance of s – n curve fatigue properties, high cycle fatigue region are remarkably affected by the ultrasonic peening due to power influence on the surface. because the dominant factor at lcf region is the applied load and there is no enough time for the fatigue cracks to propagate while at hcf region, the dominant factor is the compressive residual stress generated due to the ultrasonic. the ultrasonic takes apart in a main factor in increasing the pressure which increases the hardening of the surface and initiating a compressive residual stresses at the treated surface as well as subsurface. the energy absorption created main shock waves on the material. and these waves work to generate a high compressive residual stress. the obtained data of s – n curves for ultrasonic and as unpeened alloy can be formulated by the equations: бƒ = 788.2*nƒ 0.155 , бƒ = 841.6*nƒ 0.166 , respectively………………… (1) referring to figure (3), the ultrasonic peened specimens showed considerable plastic deformation zones. this deformation is depended on the collective effects of superior frequency impacts of particular identical strikers and ultrasonic fluctuations in handled peening pieces. the advantages of this method in addition of possible increase in fatigue life of workpieces, least amount cost, labor and power utilization. it can be concluded from figure (3) that the macrograph method is a very good tool for the comparison, because of a noticed plastic deformation. it was observed that all ultrasonic specimens’ lives increased in a range of 1.01-1.42 as given in table (3), it is common to estimate the number of cycles as some fraction of ultimate tensile strength (u) that is specific to a material type, depending on the stress level. this percentage gives a factor of safety due to ultrasonic peening from 1.42 to 1.01, based on stress level. this result is in a good agreement with what was found when 2017-t3 aluminum alloy under one, two, and three line of ultrasonic peening with rotating bending fatigue, a researcher found that the fatigue lives and strength of this alloy are significantly improved due to one line ultrasonic peening for constant and cumulative fatigue testing (ali 15 ). table (3). fatigue lives improvement due to ultrasonic peening. applied load mpa 0.3 u 0.5 u 0.7 u 0.9 u u ultrasonic lives (cycles) 51072 2308 305 67 35 unpeened lives (cycles) 72587 2629 300 59 30 safety factor due to ultrasonic peening 1.42 1.13 1.01 1.13 1.16 table (4) gives the fatigue strength for given number of cycles starting from 103 to 107. and the improvement percentage (ip) (mehmet 16) : (ip) = ………………. (2) it is observed that the specimens treated with ultrasonic have more resistant against the dynamic loading fatigue than that unpeened due to generated a hardened surface and a compressive residual stresses on the surface in addition to subsurface. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 178 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (4). comparison between the unpeened and ultrasonic peening in term of fatigue strength. fatigue life cycles 103 104 105 106 107 ultrasonic 270.16 189.07 132.32 92.6 64.4 unpeened 267.17 182.43 124.39 84.938 57.95 improvement percentage 1.1 3.63 6.37 9.02 11.1 4. conclusions 1. the up technique is a practicable and alternative choice compared to conventional treatment method. it was found to substantially improve the fatigue life. 2. the up initiated hardening surface and commenced a beneficial compressive residual stress to the order of yield stress of the material at the treated surface. cumulatively these improvements enhanced fatigue strength of the treated alloy by increasing the fatigue crack initiation life. 3. the enhancement of the fatigue lifetime is exceptionally influenced by the ultrasonic peening of the low cycle fatigue and particularly at high cycle fatigue. this can be symbolized as a factor of safety due to ultrasonic peening get in touch with to 1.42 based on stress level. references 1. ali y. , “analysis of ultrasonic peening mechanical properties and fatigue damage of 2017-t3 aluminum alloy”, sudan university of science and technology, phd thesis, (2016). 2. bousseau m. and millot t., “fatigue life improvement of welded structures by unp compared to tig dressing”. international institute of welding, paris, document xiii-2125-06, (2006). 3. herwig m., “fatigue crack growth and threshold measurements at very high frequencies”, int. mat. rev., 44, pp. 1-36. (1999). 4. iwamura y., proposal of ultrasonic peening (up) system. in: the march 2005 issue of welding technology, sanpo publications, inc, tokyo, pp. 128–133, (2005). 5. kazeno h., sekiguchi t., sakaue s., katayama y., fujikawa n. and satou h.: “jacket technology of d-runway of tokyo international airport” , the world’s first airport that consists of jacket type pier, nippon steel engineering co., ltd. technical review, vol. 1, pp. 6-14,(2010). 6. le w., “ultrasonic fatigue”, int. met. rev., 25, pp. 65-78, (1980). 7. lets global. in: http://www.lets-global.com/. 8. mehmet a., “elastic buckling of steel columns under axial compression”, american journal of civil engineering, 2(3), 102108, (2014). 9. pfeifer. in: http://www.pfeifer.de/. 10. pitec. in: http://www.pitec-gmbh.com/. 11. sonats. in: http://www.sonats-et.com/. 12. stefanie e. , “ultrasonic fatigue”, in fatigue, 96: sixth international fatigue congress, elsevier science inc., 1887-1898. (1996). 13. stefanie e. and herwig m, eds., proceedings of the international conference on fatigue in the very high cycle regime, institute of meteorology and physics, vienna, (2001). 14. tominaga t., matsuoka, k. and satoh y., “fatigue improvement method for weld repaired crane runway girder, steel construction engineering”, vol. 14, no. 55, pp. 47-58, 2007. http://www.pitec-gmbh.com/ http://www.sonats-et.com/ al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 179 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 15. yuri f. and jacob k., “increasing fatigue strength of welded elements and structures by ultrasonic impact treatment”, international institute of welding. iiw document xiii-2318-10. (2010). 16. zhao x,wang d, huo l “analysis of the s–n curves of welded joints enhanced by ultrasonic peening treatment”. mater des 32:pp.88–96, (2011). 3-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 an appraisal and analysis of boiler pipes in almusaib electric power station ali abdul mahdi department of machines and equipment engineering, uot-baghdad, iraq abstract it is hoped in this paper to find out the reasons behind the failure in boiler pipes used in almusaib electric power station. multi types of mechanical and chemical reasons were found behind the failures of these pipes. two pipes were selected for this analysis (pipe no. 6 in coil 93) and (pipe no. 7 in coil 48) were they failed selectively. it was found that these pipes of boiler respectively have failed due to overheating as first reasons. in addition, failures are due to hydrogen damage can be considered in failed pipes that lead to form (fe2o4) phase. the high sulfur containing fire products are also deposited on the outer surface of the tubes making the condensed water around the cracks acidic. in consequence, the examined pipes of boiler are respectively undergoing pitting corrosion. un-regularity in thickness of failed tubes where measured and gives an indication about how much they eroded. microstructural observations of the failed and un-failed show quenched microstructure with small amount of carbides present at the grain boundaries. keywords: boiler pipes failure, hydrogen damages, pitting corrosion. / : . . )٤٨/ ٧() ٩٣/ ٦ ( . . )(fe3o4 . . . . 1. introduction the general arrangement of the basic elements of a steam plant is illustrated schematically in the figure (1). steam is generated in a boiler from which it passes into the steam main. the steam main feeds the steam into a turbine or engine or it may pass into some other plant such as heaters or process machinery. after expending through the turbine or engine or passing through some other al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 atmosphere. this system is very inefficient and is rarely adopted in modern plant. it is used in the steam locomotive since in this case the plant needs a sufficient place for the complex steam recovery equipments, which can be installed in power station. if steam recovery plant is installed then the exhaust steam passes into a condenser where it is condensed to water, called condensate [1]. boiler pipes can be defined as the part of the boiling system that carries the steam from the boiler where the steam generated in wet state to the steam main as shown in the figure (1). if however, superheated steam is required, then the wet steam is removed from the steam space and is piped into a super heater. these pipes must be sealed reliable and working properly without any burst or leakage during the working time. the proper working of these pipes required the following: 1. uniform thickness of the steel pipe without any leakage or burst. 2. little or no scaling inside surface with no existence of any flow chocking along the pipes. 3. an advance heat transfer across the thickness. 4. capability to withstand the hot stem pressure without any deformations such as swelling. it known that these pipes actually corroded and swelling up until the burst occurs. the changes into the pipe material properties can lead to disaster consequences as mentioned above where the burst can be so expected machined onto their surfaces. ultimately, a pipe will simply wear out-oftolerance overtime and use; however, several failures, such as heat overheating and gross cracking, may cause the pipes to fail before they should. the premature failure of boiler pipes costs the electric station many thousands of dollars each year. the output electric power in the middle of iraq is seriously affected by these failures. electric power generation is one of the most demands that every country looking to develop it continuously. in our country as well as the other growing country, the electric power generation has a many problems. these problems are starting from the planning to generation, installing of power plants, and operation o has passed many strategically steps in the building of the many power stations that utilizing a heavy gas oil or the high pressurized liquidized natural gas...etc. most of these stations have suffered from many failure problems such as depreciation and corrosion or other electrical and mechanical failure. al-musaib power station is one of the national stations that used the steam turbines to derive its generator units. steam generation and delivering was the primary objective in its operation. the boiler units are suffering continuously from many failures accidents during its working. failures sometimes leads complete or partly shutdown the station. one of the most frequent failures is occurring at the pipes that connect the boiler to the supercharger or at the pipes of the supercharger itself. the objective of the failure analysis project at hand was to investigate and realize the mode and cause(s) of premature failure of boiler pipes composed of steel t 22. to obtain such purpose some boiler pipes taken from the boiler units of al-musaib power station. the engineering staff at the station supplied failed pipes used in this work officially. a variety of testing and background research on topics such as metallographic, hardness, erosion, and corrosion testing has provided several possible solutions to the failure analysis problem. visual inspection has revealed oxide inclusions near the suspected failure initiation points. anees u. malik et al [2], studied the leakage that observated from the roof tubes on the second pass of boilers 6, 7 and 8 of jeddah phase 3 plant, pipes were examined a surficial cracks and pits on the fire side of the tube wall. zhang baoyou et. al. [3], studied the rupture of a boiler pipe by using chemical analysis, scanning electron microscope, and energy dispersive spectroscopy. the results show that excess temperature caused by obstruction of stream flow was associated with the bubble clusters on the bore surface, which resulted in the creep deformation responsible for elongated grains and wall thinning. the pipe burst because the high temperature strength was below the designed standard. weili-wa et. al. [4], studied the metallographic and metallic materials of three boilers burst tube in accident, which provide a basis for diagnosis and determine the common cause of the boiler al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 tube burst accidents, and also set a foundation for the prevention measures of the steam boiler tube burst accident. by analysis and comparison of the components, macroscopic and microscopic morphology of three blast tubes, the major cause of the boiler tube burst is too high wall temperature of boiler tube. because the circulated water in steam boiler have more carbonate content, the carbonate was crystallized in the wall of tube at the point of the overheated section, so the thermal resistance increases and the boiler tube wall temperature growths and metal performance failures, finally the accident of steam boiler tube burst happens. chen qi-sheng et. al. [5], investigate the tube burst accident in the oil filed. it not only influences the length of boiler life, but also creates the huge economic loss. in view of tube burst accident arising from factory of production crude oil, based on the examination data, the reason of burst has been analyzed and the final conclusion also has been draw. the preventive measure and the identical accident were prevented. 2. experimental procedure the properties of t22 steels are dependent on the microstructure, the composition, and the heat or surface treatments. the microstructure of t22 steel is composed of pearlite in ferrite matrix with various alloying element distributed within colonies. the size and distribution of pearlitic structure plays a key role in fracture. coarse pearlitic result in facilitating fractures propagation. (zhang, 2006) there are many types of pipe failures including deformation, fracture, cracking, burst, erosion, etching, pitting, and exfoliation. of these failures, there are many possible causes. to decrease the likelihood of failure the following criteria should be met: 1. design that is compatible with the pipe material selected and with the planned processing procedure. 2. selection of material that is compatible with the design and processing procedure. 3. selection of a heat treating procedure that is compatible with design and material. 4. control of the specified heat-treating procedure. 5. control of the finishing operations. 6. control of boiler pipes setup (particularly alignment) in the equipment. 7. boiler operation, specifically avoidance of overloading and overheating. 8. control the quality of water used to generate the steam such as ph level and other water properties. all the potential failure causes are associated with stress present in the pipe, which are generated undersized radii, inadequate welding or assembly, and thin sections or sudden variations in section thickness, are often the causes of these stresses that can cause pipe failure. the paper concentrated on the criteria one and seven and eight as starting points. these criteria were most easily discernable as potential causes of premature pipe failure. criteria 1, 7 and 8 initially, criteria one, seven, and eight were investigated as well as literature reviews. for instance, t22 steels have typical applications as boiler pipes due to the metallurgical and chemical behavior. the simplicity of a boiler pipes as compared to other intricate part coupled with the fact that t22 steel has been used as an industry-wide boiler pipe material for many years eliminated criterion one as a potential cause of failure. however, the chemistry specifications of t22 will be checked to positively eliminate criterion one. (boiler operation, specifically avoidance of overloading and overheating) was a clear starting point because all pipes were subjected to the same operation conditions. only definite numbers of pipes were failing prematurely (and most often), and so this did not indicate an overloading or overheating issue. criterion 7 is investigated as a possible cause of premature pipe failure. criterion 8 was a starting point due to the use of single grade of stock materials in the boiler pipes. the objective was to find out whether pipes were failing more often (or all of the time). the al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 cleanliness of the steel is a measure of the amount of inclusions in the microstructure, an abundance of inclusions can cause premature pipe failure. visual examination upon receipt of each pipe sample, photographs were taken and the samples were labeled systematically. a list of sample conditions can be verified in table (1). both the failed and unfailed pipes (of varying part number) saw various service conditions. all of the failed and un-failed samples were positions on the bottom during service; and, all pipe-operating temperatures (that were recorded) were less than 265 c. n the manner in which each of the failed pipes failed was identical. figure 2 is a representative photograph of the appearance of the failed pipes. the failures appeared to have started at the inner surface of the pipe and propagated across the thickness. test procedures the two types of boiler pipes were analyzes for material deficiencies using hardness testers, metallographic. a limited amount of mechanical properties testing also conducted on the boiler pipes. marco-hardness readings were taken on a cross-section of each pipe material and in numerous places on each received pipe. this was conducted with a new age brinell tester. any signs of poor heat treatment or wrong alloy composition would be identified from this testing.. this test was conducted with a 50 kg load. the intent of this test was to determine the presence of, approximate depth and hardness of the each place across the thickness of each pipe. the selected locations for hardness test are as follows in the following schematic diagram as shown in figure (3): metallographic four samples of each pipe were sectioned from the failing region and prepared for microstructural analysis via standard metallographic procedures. a 2% nital etch was used on all samples. this would reveal any signs of poor heat treatment or other imperfections in the microstructure. chemical analysis 22 steel alloy, sections were sent to an outside laboratory (ministry of science & technology-baghdad) the chemical composition was measured using "spectrum analysis for metals" for chemical analysis. the results of actual chemical composition are given in table (2). 3. results and discussion the following chapter aims to explore and discuss the results obtained from the experimental procedure. results can be classified into three categories; mechanical, metallurgical and electrochemical results. a recent accident in most power plants and in al-musaib electric power station involving a bursting steam pipe that leads may be to disaster. investigated set of pipes in the station above registered a few accidents of pipe burst. the bursted pipes received shows a noticeable remarks about the reasons by which the burst occurs. pipe bursting is caused by corrosion and erosion of areas inside the pipe that cause the pipe walls to thin down and eventually burst under pressure. these corrosion and erosion areas can be found by using ultra-sound as a detection method. unfortunately, this method is very restricted to use nevertheless that the pipe must be installed and hot stem flowing through it [4]. in this paper, the failed pipes have not burst but they suffer from a sever pitting corrosion and erosion. measuring thickness along the pipe samples can give a clear indication about the corrosionerosion along the steam side as can be seen in figure (4). erosion of pipes al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 a common type of erosion is known as cavitations erosion and is caused by sudden flash of liquid into vapor bubbles followed by immediate collapse of bubbles; the subsequent shock wave generated by the flashing and collapsing of vapor or dissolved gas creates stress erosion on the pipe wall. similar phenomenon can be seen on high-speed boat propellers, which run in cavitations conditions. erosion of investigated pipes is so clear according to the figures above. the degradation in thickness along the pipe reflects the ideas about some expected kind of erosion has occurred. pipe no.6/coil 92 had been eroded clearly in the locations (2-12 cm) and (20-26 cm) in the 30 cm long investigated. pitting corrosion observations tubes 6/coil93 and 7/coil48 had few crack openings and deep pits around it. from the figures (5), it is evident that pitting started at the surface of the tube near the crack and progressed downwards undercutting the surface. it was also observed that depth of the pit increased as one moves away from the crack. no chemical attack was found on the steam-side of the tube wall. pitting corrosion of the surface of these tubes does not appear to be due to difference in oxygen concentration, because for such type of pits presence of crevices and/or deposits is essential. visual inspection of the pits and their size indicate that they have formed under highly acidic condition. when the steam flowing in the tube at a pressure of around (7 mpa) escapes through the narrow cracks, it will cool down near the end of the crack due to the pressure gradient (joule-thomson effect). this cooling of the steam will result in: 1. condensation of steam into water near the crack. 2. dissolution of sulfurous gases of the fire product and formation of acidic water. as the temperature of the surface of the tube will be less, the condensation of escaping steam will be more, and consequently pitting corrosion will be more. if we try to analyze the temperature history of all the failed tubes under study on the basis of their extent of swelling, reduction in the wall thickness and spheroidized and quenched microstructures, it seems that the temperature experienced by the tubes 6coil93, 7coil 48 and was less than other failed tubes according to some historical accidents in station. therefore, severity of the pitting corrosion of above mentioned tubes is more. overheating inspection conditions one of the roof panel tubes of boiler 6, designated as 6/93 in fig. (5) had a swollen portion with many un-regularities and pitting on it. longitudinal section of the failed area, cleaned with inhibited 3% hydrochloric acid solution, revealed that the fine cracks had initiated at the steam -side of the tube. some of the cracks had crossed the entire thickness of the tube and had opening at the other side. failure of roof panel tube of boiler 7/48 also appears to be due to overheating of the tube. tube 7/48 had pits around the fine crack opening. analysis of oxide scales thick black oxide scales deposited on the steam-side surface of the tube and brown oxide scale formed on the outer surface of the tube. it was found that the oxide scales deposited on the steamside surface is composed of magnetite (fe3o4) while the scales on outer surface contains hematite and wustite (fe2o3 + feo) as expected. metallographic evaluation metallographic analysis is an important tool for analyzing material temperature history. when carbon steels are exposed to temperatures above 482°c but less than the lower critical temperature (723°c) this steel is subjected to spheroidization. the carbides present in the steel in annealed condition are not in their lower energy state and exposure to higher temperature results in the coalescence of these carbides into spheroidal form. if the tube wall is ruptured and temperature is al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 more than the lower critical temperature, the rapid cooling effect of the escaping steam will result in a distinct quenched microstructure form. microscopic studies of cross-section of failure zone of boiler tube 6/93 and 7/48 show quenched microstructure with small amount of carbides present at the grain boundaries (fig. 6 and 7). on comparing the above microstructures of failed area with un-failed area of tube 6/93, 7/48, the former appears as quenched overheated microstructures. this shows that the exposure temperatures of the above failed areas have exceeded the lower critical temperature and were exposed to this temperature for quite long time. knowing that, the strength of steel is nearly constant up to about 454°c. boiler tubes are overheated due to the internal deposits insulating the tube metal from the cooling effect of steam. as the deposits do not form uniformly along the tube, overheating is always localized in nature. overheating failures are of two types: short-term and long-term. short-term overheating failures result when (i) tube metal temperature increases hundreds of degrees above design temperature (ii) there is blockage of the tube and (iii) loss of drum water level. this type of tube failure exhibits considerable creep elongation resulting in considerable reduction in wall thickness. sometimes the tube blows up into the furnace and shows a knife edged failure opening. hydrogen damage a serious and catastrophic failure of carbon steel pipes of boilers, exposed to high temperature (> 500°c) and high pressure of steam (>1500 psi) for a long time is that associated with the decarburization of steels resulting into hydrogen damage. characteristically a deposit plays a key role in: (a) overheating of metal and (b) creating relatively high rates of carbon diffusion, which is evident by the decarburization of the steel on both surfaces. nevertheless, the cause of decarburization of steam-side surface is expected to be steam while that of fireside it is the co2 gas. decarburization at the steam-side surface is represented by the equations, [6]: 3 fe + 4h2o = fe3o4 + 4 h2 (1) fe3c + 2h2 = 3fe+ ch4 (2) decarburization at the fire-side surface is represented by the equation: fe3c+4co2 = 3feo+5co (3) an illustration of the environment that results in hydrogen damage is shown in fig. (8). as the partial pressure of hydrogen eq. (1) increases, it diffuses into the steel and reacts with carbides forming methane gas eq. (2) which exerts an internal pressure. the decarburized metal gets embrittled and fails to withstand this internal pressure. as the size of methane molecule is bigger than co molecule and there is a high pressure of steam inside the tube, more cracks have initiated at steam-side surface of the tube. the reason for cracks being circumferential in nature appears to be thermal residual stresses which developed due to localized heating and acted parallel to the length of the tube. hardness testing results discussion hardness numbers reflects to some extent, the change in the microstructure along the cross section of boiler shown in the figure (9 and 10). the following figures show a comparison between the hardness numbers of failed and un-failed of the two pipes adopted in this project. it is clear from both figures down that a noticeable difference between the failed and un-failed hardness results. in figure (9), pipe no.7 in coil 48 shows a distinct difference in hardness numbers, gave a clear picture about what is going on in this pipe. the first indication put that, a softening phenomenon has occurred clearly in this failed pipe. furthermore the swinging of hardness numbers al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 and their drops in comparison with the un-failed pipe gives an indication that, the pipe has subjected to an overheating during its operation. it is usual that, the boiler pipe operating with temperature up to (256°c) in most cases. any increasing in operating temperature affects the microstructure of the pipe materials. pipe materials were manufacturing from low carbon steel (i.e. 0.18% c). 4. conclusions the following remarks can be concluded: 1. pipes 6/93 and 7/48 of boiler respectively have failed due to overheating. 2. in addition, failure by hydrogen damage can be considered in failed pipes. 3. the high sulfur containing fire products are deposited on the outer surface of the tubes making the condensed water around the cracks acidic. 4. in consequence, pipes 6/93 and 7/48 of boiler respectively undergo pitting corrosion. 5. un-regularity in thickness of failed tubes gives an indication about how much they eroded. 6. microstructural observations of the failed and un-failed show quenched microstructure with small amount of carbides present at the grain boundaries. acknowledgments: the remarkable cooperation of the staff in al-musaib power station must be singled out for special thanks and grateful. references 1combustion engineering, inc. combustion 3rd, windsor, ct. 1981. 2anees u. malik, nausha asrar, m. f. alpresented in the second saudi symposium on energy utilization and conservation, kfupm,27-30 november, 1994, dhahran. 3zhang baoyou, lai zhonghong, cui yuexian and fan xigang, "analysis of a boiler pipe rupture", engineering failure analysis, volume 13, issue 1, pages 75-79, january 2006. 4weili-wa,su hui,shen long-she (liaoning shihua), " study for accident of steam boiler tube burst", pressure vessel technology ;2008. 5chen qi-sheng, chen bao-dong, "analysis on tube burst of injecting steam boiler and burst control", pressure vessel technology ;2007. 6h.a.klein and h.a.grabowski, corrosion and hydrogen damage in high pressure boilers, presented at the second annual education forum on corrosion , nace, drexel institute of technology, philadelphia, sept. 15 to 17, 1964. 7materials and processes in manufacturing , 10th edition , john wiley & sons , 2008 . 8george y. lai high temperature corrosion and materials applications ,december 1, 2007 . 9frederick john rowan on boiler incrustation and corrosion general books llc ,december 23, 2009. 10william wallace christie boiler-waters, scale, corrosion, foaming , nabu press , 2010. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 table (1): boiler characteristics as provided by al-musaib electric power station pipe no. 7 2 position coil no. 48 coil no. 93 condition failed failed outer diameter od (100mm) od (100mm) thickness 5mm 5mm operating pressure (mpa) 5 5 operating temperature °c 265 265 manufacturing method deep drawing deep drawing table (2) chemical composition analysis of failed boiler pipes samples c% mn% si% fe% sample no. 1 0.18 0.45 0.20 sample no. 2 0.18 0.45 0.20 remainder remainder figure (1): a schematic representation of the electric power station using a steam turbine al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (2): a-longitudinal cross section of damaged and undamaged boiler pipes. bhalf rings samples taken from each pipe. figure (3): schematic representation of the half ring pipe sample with specific locations of hardness readings. 8 8.5 9 9.5 10 10.5 0 2 4 6 8 101214161820222324262830 thickness (mm) failed un cm figure (4): thickness measurement along the failed and un-failed pipe no.6/coil92. a b al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (5): surface of pipe (6/93). figure (6): micrograph structure of the un-failed pipe no. 6/93, (200x) figure (7): micrograph structure of the failed pipe no. 6/93, (200x) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (8): schematic representation of expected hydrogen damage mechanism in boiler tube. [5] 105 110 115 120 125 130 135 140 1 2 3 4 5 6 7 location no. hb no.7 failed no. 7 un-failed figure (9): comparison between hardness results of failed and un-failed pipe no. 7/coil no.48 figure (10): comparison between hardness results of failed and un-failed pipe no. 6/coil no.93 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 24 effect of oil on strength of normal and high performanc concrete abstract: the main objective of this investigation is to study the effect of oil (kerosene, gas oil and crude oil) on the compressive and tensile strengths of high performance concrete and to compare the behavior with that of normal strength concrete. four exposure periods were used for each specimen and for each liquid, 30, 60, 90 and 120 days after 28 days water curing. to provide a basis for comparison, reference specimens were cast and exposed to water for a respective time of test. the test results showed that the loss in mechanical properties (compressive and splitting tensile strengths) resulting from exposure to oil was relatively smaller for high performance concrete (hpc) compared with normal strength concrete (nsc). the difference was about 10 percent. furthermore, the reduction in compressive and splitting tensile strengths of nsc and hpc increased with decrease in viscosity of oil in the entire period of exposure. keywords: high performance concrete, normal strength concrete, compressive strength, splitting tensile strength, kerosene, gas oil, crude oil. االداء االعتیادیة والعالیةتأثیر البترول على مقاومة الخرسانة :الخالصة األمر الذي ش جع , إن استخدام صفائح الحدید في خزن البترول قد اكتنفتھ العدید من المشاكل وباألخص األداء الخدمي واألمان بحث على االستعمال الكبیر للخرسانة المسلحة أو مسبقة الجھد لحمایة و خزن و نقل المشتقات النفطیة إن الھدف الرئیسي من ھذا ال على مقاومة االنضغاط والشد االنشطاري للخرسانة عالی ة األداء ) زیت الغاز والنفط الخام , النفط األبیض (ھو دراسة تأثیر البترول .سلوك الخرسانة االعتیادیة ومقارنة سلوك ھذه الخرسانة مع زی ت الغ از وال نفط الخ ام , نیة لل نفط األب یض عرض ت ك ل النم اذج الخرس ا , الرطبة والتجفیف بالفرن ة یوم من المعالج 28 بعد . أما النماذج المرجعیة فقد تم إنضاجھا بالماء لحین إجراء الفحص. یوم 120 و 90, 60, 30لفترات أشارت نتائج الفحص بان الفقدان في مقاومة االنضغاط والشد االنشطاري الناتج من التعرض للبترول كان اقل نسبیا للخرسانة إض افة إل ى ذل ك إن االنخف اض ف ي مقاوم ة االن ضغاط %. 10االخ تالف ك ان تقریب ا . ی ة األداء مقارن ة م ع الخرس انة االعتیادی ة عال . والشد االنشطاري للخرسانة عالیة األداء والخرسانة االعتیادیة ازداد بنقصان لزوجة البترول خالل كل فترات التعرض dr. ali t. jasim college of engineering university of kufa faris a. jawad college of engineering university of kufa فارس عباس جواد كلیة الھندسة ة الكوفةجامع علي طالب جاسم. د كلیة الھندسة جامعة الكوفة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 25 introduction: as a results of the critical shortage of steel plate and problems of serviceability and safe, large concrete structures, reinforced or pre-stressed, are being built for the production, storage and transportation of oil. reinforced concrete tanks constructed in the past have performed satisfactorily under many various conditions and their advantages include shock and fire resistance, cheap maintenance and the fact that they may be built to much longer dimensions than steel tanks. however, concrete tanks have some disadvantages, such as the unknown behavior of concrete in direct contact with hydrocarbons, leakage or contamination of the liquid, construction difficulties due to the need to prevent differential settlement and finally the difficult of any modifications and repairs. there is a difference in the behavior of the petroleum storage concrete tanks and the water storage concrete tanks. matti (1976) confirmed that leakage from concrete may be reduced with time due to enclosure of some of the voids, disconnection of the capillary channels and healing of some of the cracks due to the continuous hydration, and or accumulation of impurities. because of the inert nature of petroleum towards concrete, such continued hydration is less likely to occur in concrete petroleum tanks, but the wax deposits that are found in crude oil may decrease the permeability of concrete . this study will discuss the suitability of high performance concrete (hpc) in the field of oil retaining structures, like storage tanks, pavement of airports, highways and other floors that may be exposed to oil products. objective: the main objective of this investigation is to study the effect of oil (kerosene, gas oil and crude oil) on the compressive and tensile strengths of high performance concrete and to compare the behavior with that of conventional concrete. experimental program: 1 materials: 1.1 cement: ordinary portland cement manufactured by yamama cement factory was used in all mixes throughout this study. the percentage oxide composition and physical properties of the cement indicated that the adopted cement conforms to the iraqi specification no.5 /1984. 1.2 fine aggregate: normal weight natural sand from al-ukhaidher region was used as fine aggregate in this work. the used sand was within zone ii according to the requirements of the iraqi specification no.45/1984. the specific gravity of the fine aggregate, absorption, and sulfate content (as so3) were 2.61, 1.7%, and 0.09% respectively. 1.3 coarse aggregate: natural crushed gravel of a maximum size 12.5 mm from al–nebaey region was used in this work .the specific gravity of the coarse aggregate, absorption and sulfate content (as so3) were (2.63), (0.6%) and (0.06%) respectively. 1.4 admixture: 1.4.1 high range water reducing admixture (hrwra): a high performance concrete superplasticizer based on modified polycarboxylic ether which is known commercially (glenium 51) was used throughout this investigation as a (hrwra). it is a third generation of superplasticizers and it complies with astm 494-2003 type a and f. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 26 table (1) indicates the technical description of the aqueous solution of superplasticizer used throughout this study. 1.4.2 condensed silica fume (csf): silica fume ms-90 was used in this study. the relative density and surface area of silica fume were 2.12 and 18000 m2/kg respectively. 1.5 oil three types of oil products were used in this study, kerosene, gas oil and crude oil products. the oil were brought from al-najaf station and stored in air tight steel containers to avoid losses and contamination. table (2) shows the viscosity of oil used. 2 mixture proportions: specimens were made from two type of concrete, the first was normal strength concrete (nsc) and the other was high performance concrete (hpc). the details of the two concrete mixes used throughout this investigation are shown in table (3). 3 preparation and exposure of specimens after were demoulded, the specimens were cured in tap water at laboratory temperature up to the age of 28 days. after that they were dried in oven at 75 oc until reaching almost a constant weight four exposure periods were used for each specimen and for each liquid ( kerosene, gas oil crude oil, and water as reference). these periods were 30, 60, 90 and 120 days after 28 days water curing. to provide a basis for comparison, reference specimens were cast and exposed to water for a respective time of test. 4 tests: 4.1 compressive strength: the compressive strength test was determined according to b.s. 1881 part 116. this test was conducted on 150 mm cubes using an electrical testing machine with a capacity of 2000 kn at loading rate of 15 mpa per minute. 4.2 splitting tensile strength: the splitting tensile strength test was performed according to astm c496, (2003). (d=150 mm, h=300 mm) concrete cylinders were used. the specimens were tested using an electrical testing machine with a capacity of 2000 kn. results and discussion: 1 compressive strength: the test results for compressive strength of nsc and hpc exposed to different oils up to age of 120 days exposure are given in table (4) and the change in compressive strength due to oil products compared with water strength are plotted in figures (1) and (2). the results shown in figures (1) and (2) indicate that the specimens which were kept continuously cured in water after demoulded and tested in a saturated surface dry condition, showed a continuous increase in compressive strength with age. after 120 days of moist curing, the increase in the compressive strengths for nsc and hpc were 23.3 and 8.8 percent respectively compared with 28 days strength. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 27 test results also showed that the compressive strength of concrete specimens exposed to oil decreased moderately with time. for the nsc specimens exposed to the oil, the maximum reduction values were about 15,19 and 25 percent for specimen exposed to crude oil, gas oil and kerosene for 120 days respectively. on the other hand, the maximum reduction value in the compressive strength of hpc specimens exposed to crude oil, gas oil and kerosene were about 6, 8 and 12 percent for 120 days respectively. it is obvious from these results that the high performance concrete was less affected than nsc after exposure to oil. this can be attributed to the fact that the microstructure of high performance concrete with water-binder ratio of 0.3 especially those densifed with silica fume becomes so dense (holm and bremner, 2000) that it is difficult for the oil to penetrate into or through concrete . furthermore, test results showed that the reduction in the compressive strength of both types of concrete increases with decrease in viscosity of oil. for example, after 120 days of exposure to oil, the decrease in compressive strength was 25, 19 and 15 percent for nsc and 12, 8 and 6 percent for hpc exposed to kerosene, gas oil and crude oil respectively. this is attributed of the fact the mineral oil has no effect on the quality of concrete. the harm adjective of the oils depends on their viscosity, the higher viscosity of the oil, the less dangerous it is to concrete. therefore viscosity of the oil is very important property for oil storage tanks (watson and oyeka, (1981), spamer,(1944) and hernibrock, (1944). 4.2 splitting tensile strength: the test results of splitting tensile strength of nsc and hpc exposed to different oils up to age of 120 days exposure are given in table (5). figures (3) and (4) showed the change in splitting tensile strength of the concrete specimens exposed to different oil compared with that of those cured in water of the same age. as shown in figures (3) and (4), the loss of splitting tensile strength resulting from exposure to oil was higher for nsc compared to the hpc. for the nsc, the loss in splitting tensile strength was of the order of 20, 17 and 10 percent of the water tensile strength for specimens exposed to kerosene gas oil and crude oil respectively. while for hpc the reduction was 10, 7 and 5 percent respectively with same exposure period of 120 days. it is clear from these results that the viscosity of oil had significant effect on splitting tensile strength of concrete during exposure to oil . in addition, the test results for splitting tensile strength follow a somewhat similar pattern to that of compressive strength, but with a percent of reduction less than the reduction which was observed in compressive strength . this behavior is also noted by al-hamdani (1991). conclusions: based on the results of this study , the following conclusions can be drawn: 1the loss on mechanical properties (compressive and splitting tensile strengths) resulting from exposure to oil was relatively smaller for hpc compared with nsc. the difference was about 10 percent. 2the reduction in compressive and splitting tensile strengths of nsc and hpc increases with decrease in viscosity of oil in the entire period of exposure. 3the test results for compressive strength follow a somewhat similar pattern to that of splitting tensile strength, but with a percent of reduction more than the reduction which were observed in tensile strength al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 28 references: al-hamdani, z.k.,(1999),"improvement of the performance of concrete against oil products", m.sc., thesis, university of technology astm c496, (2003),"standard test methods for splitting tensile strength of cylindrical", astm standards, vol. 04.02, pp. 1 –4. b.s. 1881, part 116," method for determination of compressive strength of concrete cubes", british standard institute, pp. 1-3. hernibrock, f.b.,(1944),"the effectiveness of various treatment and coating for concrete in reducing penetration of kerosene", aci journal, proc. vol. 41, september, pp. 13-20. holm, t.a., and bremner, t.w. (2000),"state-of-the art report on high-strength, highdurability structural low-density concrete for applications in sever marine environments", u.s. army crops of engineers washington, august, 45p.. iraqi specification no.5 (1984) "portland cement". iraqi specification no.45 (1984) "aggregate from natural sources for concrete and construction". matti, m.a., (1976),"some properties and permeability of concrete in direct contact with crude oil", ph.d. thesis, university of sheffield. spamer, m.a., (1944),"navy installation of protective linings for prestressed concrete tanks containing liquids fuels", aci journal, proc., vol. 40, april, pp. 417-428. watson, a.t., and oyeka, c.c., (1981) "oil permeability of hardened cement paste and concrete", magazine of concrete research, vol. 33, no. 115,june, pp.85-96. table (1) technical description of high range water reducing admixture (typical properties) main action concrete superplasticizer form viscous liquid color light brown relative density 1.1 @20oc ph value 6.6 viscosity 128 ± 1.30cps @20oc transport no classified as dangerous labeling no hazard label required al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 29 table (2) viscosity of oil used table (3) mix proportion and properties of concrete nsc w/c= 0.5 hpc w/cm=0.3 cement (kg/m3) 300 543 water (kg/m3) 150 177 coarse aggregate (kg/m3) 1200 880 fine aggregate (kg/m3) 650 750 silica fume (kg/m3) 47 m at er ia ls hrwra (kg/m3) 14.75 fresh concrete slump (mm) 80 85 hardened concrete compressive strength (mpa) 28-day 28 71 pr op er tie s splitting tensile strength (mpa) 28-day 2.6 3.4 table (4) compressive strength results of the test specimens compressive strength (mpa) liquid age (day) nsc hpc 28 23.10 71.00 30* 25.30 75.50 60* 26.70 76.60 90* 27.20 77.00 water 120* 28.50 77.31 30* 24.94 74.10 60* 23.60 73.46 90* 22.23 70.88 kerosene 120* 21.37 68.03 30* 25.01 74.80 60* 24.63 73.23 90* 23.92 72.81 gas oil 120* 23.08 71.11 30* 25.00 75.01 60* 24.70 74.63 90* 24.10 73.33 crude oil 120* 24.22 72.66 *after 28-day moist curing oil viscosity ( centipoises) at 25 oc kerosene 1.089 gas oil 3.780 crude oil 6.918 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 30 table (5) splitting tensile strength results of the test specimens splitting tensile strength (mpa) liquid age (day) nsc hpc 28 2.40 3.41 30* 2.68 3.85 60* 2.75 3.88 90* 2.81 3.98 water 120* 2.96 4.01 30* 2.43 3.65 60* 2.41 3.63 90* 2.39 3.61 kerosene 120* 2.37 3.60 30* 2.48 3.75 60* 2.47 3.74 90* 2.46 3.73 gas oil 120* 2.45 3.72 30* 2.68 3.85 60* 2.67 3.82 90* 2.66 3.81 crude oil 120* 2.66 3.80 *after 28-day moist curing 0.6 0.7 0.8 0.9 1 0 30 60 90 120 age (day) fc (t )/ fw kerosene gas oil crude oil figure(1) relative change in compressive strength of nsc exposed to oil with time al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 31 0.8 0.9 1 1.1 0 30 60 90 120 age (day) fc (t )/ fw kerosene gas oil crude oil figure (2) relative change in compressive strength of hpc exposed to oil with time 0.6 0.7 0.8 0.9 1 1.1 0 30 60 90 120 age (day) ft (t )/ fw kerosene gas oil crude oil figure (3) relative change in splitting tensile strength of nsc exposed to oil with time al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 32 0.8 0.9 1 1.1 0 30 60 90 120 age (day) ft (t )/ fw kerosene gas oil crude oil figure (4) relative change in splitting tensile strength of hpc exposed to oil with time simulation performance of a 10gb/s polarization shift keying system al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 simulation performance of a 40 gbit/s polarization shift keying system dr. w. y. hussen department of laser and optoelectronic engineering university of technology baghdad -iraq abstract polarization shift keying (polsk) and advanced modulation formats represent the future in development of high speeds communications. in this paper the feasibility of polsk systems combining multilevel modulation is studied. the performance of 40 gbit/s polsk systems is tested by a optical simulation software. optimums values for set the signals and eye diagrams are evaluated. furthermore numerical simulations are performed to evaluate the transmission performance of a 40 gbit/s polsk system, and a transmission through various optical fiber lengths is demonstrated. keywords: polarization shift keying, modulation format, polarization, jones vectors, optical fiber communication 40محاكاة أداء لنظام اتصاالت باستخدام تناوب مفتاح الرموز المستقطب بمعدل gbit/ وليد ياسين حسن. د قسم هندسة الليزر وااللكترونيات البصرية العراقبغداد–الجامعة التكنولوجية موجزال االتـصاالت ذات تناوب مفتاح الرموز المستقطب هو شكل للتضمين المتقدم يمثل مستقبل التطور فـي في هذا النص تم دراسة قابلية تنفيذ نظام اتصاالت تناوب مفتاح الرموز المستقطب بدمج . السرعات العالية بواسـطة gbit/s 40تم فحص أداء أنظمة تناوب مفتاح الرموز المـستقطب بـسرعة . مستويات المتعددة يجاد مخططـات العـين لمنظومـة االتـصاالت تم تقدير كل من القيم المثلى لإلشارات وإ .محاكاة حاسوبية و استعراض النتـائج 40gbit/sعالوة على هذا نفذت المحاكاة العددية لتقييم أداء اتصال بسرعة . المعنية .المختلفة للنظام االتصاالت باستخدام مختلف األطوال أللياف البصرية 1. introduction the bandwidth-distance product is a key figure-of-merit of lightwave systems. to increase the capacity of lightwave systems, increase in data-rate per channel and tighter channel spacing in dense wavelength division multiplexing (dwdm) systems are possible solution. in such high speed dwdm a system, linear and nonlinear impairments become worst. these linear impairments w. y. hussen include chromatic dispersion (cd) and polarization mode dispersion (pmd), nonlinear impairments include self phase modulation (spm), cross phase modulation (xpm) and four-wave mixing (fwm) [agrawal, 2002]. to minimize both the linear and the nonlinear impairment over transmission fiber, an optical modulation format is needed [winzer, 2006]. a modulation format with a narrow optical spectrum can enhanced spectral efficiency and tolerates more cd distortion [chbat, 1997]. a modulation format with constant optical power can be less susceptible to spm and xpm; modulation format with multiple signal levels will carry more information than binary signals and its longer symbol duration will reduce the distortion include by cd and pmd [kaminor, 2002]. 2. background of optical signal generation the signal generation in terms of optical transmission systems can be understood as the modulation of laser source with an electrical binary signal. according to this, it can be speaking of the optical signal modulation and demodulation formats. the modulated complex electric field is given by) [agrawal, 2002] )1())(cos().()()( , tttetate llllol φω +⋅= →→ where ao,l is the amplitude of the optical field, ωl is the optical angular frequency of the light source, φl is the optical phase and represents the polarization vector known as jones-vector of the signal. these four parameters are four degrees of freedom employed for the optical signal generation. each of these parameters can be modulated by an electrical binary base band signal q(t) [hodzie, 2003]; → le )2()()( ∑ ∞ −∞= −−= i bi ittgqtq with the information coefficients ]1,0[q i ∈ and the base band pulse shape g(t) delayed by multiples of the bit period tb . basically on which signal parameter is modulated, it can be distinguished between amplitude shift keying (ask), frequency shift keying (fsk), phase shift keying (psk) and polarization shift keying (polsk) [hodzie, 2003]. 3. polarization shift keying (polsk) the optical polsk signal is generated by switching the signal polarization between two orthogonal states of polarization. the jones vector describes efficiency the polarization of a plane wave. in this representation, the plane wave [yariv, 2003]; [ ] )3(re),( )( kztjaetze −= ω where a is a complex vector which lies in the x-y plane. this plane wave is expressed in terms of its complex amplitude as a column vector;[edward, 2005] )4( ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ = yj y xj x ea ea j δ δ notice that the jones vector is complex vector, that is, its elements are complex number j is not a vector in the real physical space; rather it is a vector in abstract mathematical space. to obtain, as an example, the real (x) component of the electric field, we must perform the operation, [ ] [ ] )5(rere)( ( xtjxtjxx eaejte δωω +== al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 130 simulation performance of a 40 gbit/s polarization shift keying system the jones vector contains complete information about the amplitudes and the phase of the electric-field-vector components. it thus specifies the wave uniquely, if we are only interested in the polarization state of the wave, it is convenient to use the normalized jones vector which satisfies the condition that; )6(1* =⋅ jj where the asterisk (*) denotes complex conjugation. thus a linearly polarized light wave with the electric field vector oscillating a long a given direction can be represented by the jones vector; [edward, 2005] )7( sin cos ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ ψ ψ where ψ is the azimuth angle of the oscillation direction with respect to the x-axis. the state of polarization which is orthogonal to the state represented by equation (7) can be obtained by the substitution of ψ by ( 2/πψ + ), leading to a jones vector )8( cos sin ⎥ ⎦ ⎤ ⎢ ⎣ ⎡− ψ ψ for special case when 0=ψ represents linearly polarized waves whose electric field vector oscillates along the coordinate axes, the jones vectors are given by[edward, 2005]; ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ = 0 1 x ^ )9( 1 0^ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ =y 4. generation of 40 gbit/s polsk signals the polsk belong to the group of novel modulation formats targeting the suppression of nonlinear system degradation and an enhancement of the maximum transmission length in high bit rate transmission systems [cheng, 2002]. the signal generation of polsk signals is presented in figure 1. it consists of two main stages, first stage that generates the return to zero (rz) signals and second stage operate as polarization modulator. in the first modulator stage, optical rz pulses are generated in a mach zehnder modulator (mzm), which is driven by an electrically filtered rz signal at 40 ghz. the electric rz signal is generated by an electrical rz coder and an additional electrical filter. the polarization switching between adjacent rz pulses is realized by the polarization modulation of pulses in an additional polarization modulator (polm). the polarization state of the optical signal is adjusted to a linear polarization (angle of 45o) at the polm input by a polarization controller (pc). by a polarization beam splitter (pbs), a rz signal is separated into xand ypolarization components. the modulation of y-polarization component is realized in the phase modulator (pm). as drive signal of the phase modulator a rectangular electrical clock or an electrical bit pattern with alternating bits (1010101....) can be used. the two polarization components are joined with a polarization beam combiner (pbc). if the pm drive signal is a mark (”1”) the phase of the y-polarization component will be shifted by 180o causing a polarization switching of 90o in the total signal polarization. this results in a pulse polarization angle of -45o after the pbc. for a space (”0”) drive signal at the input of pm, no phase modulation occurs and the total pulse polarization at the polm output remains unchanged (450). al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 131 w. y. hussen the signal detection of polsk modulation is done with a conventional nrz detector. also polarization switching between orthogonal bits can be implemented as additional modulation stage in combination with various ask-based modulation formats. 5. simulation results and discussion figure 2 illustrate optical spectra of 40 gb/s polsk signal. the alternately polarized optical spectra are broader than conventional rz or nrz spectra as shown in figure 2-a. this can be explained by the fact that the spectrum of an alternate polarized format is a superposition of two polarization components with different optical spectra. the spectrum of x-polarization is conventional rz spectrum as shown in figure 2-b, whereas the spectrum of the y-component is a carrier suppressed returned to zero (csrz) spectrum due to the employed phase modulation as shown in figure 2-c. this explains the side bands at 20ghz left and right of the carrier if the pm is driven with a 20 ghz clock. the polarization state versus frequency of optical signal at end of polsk modulator is illustrated in figure 3. the azimuth angle is changed from -90o to 90o according to the optical signal frequency. also the ellipticity angle is changed from 45o to 45o versus optical signal frequency. for ease of visualization, polarization states are often specified in terms of the polarization ellipse, specifically its orientation and elongation. a common parameterization uses the azimuth angle (ψ ) (the angle between the major semi-axis of the ellipse and the x -axis) and the ellipticity (ε), which represent the ratio of the two semi-axes) as shown fig.(4). an ellipticity of zero corresponds to linear polarization and an ellipticity of 1 corresponds to circular polarization. the arctangent of the ellipticity, χ = arctan (ε) (the "ellipticity angle"), is also commonly used. the signal polarization at end of modulator is elliptical display in fig.(4). from the ellipse, the azimuth angle and ellipticity angle are measured and they equal to 44.7o and 2o respectively. the polsk signal is tested by transmitting the signal over 30km, 60km and 90km of standard single mode fiber. single mode fiber was chosen to minimize the influence of dispersion and the main limitation of the system as it is seen from the simulation. on the receiver side of the system, the avalanche photodiode (apd) is used to detect signals and eye-diagram analyzers to evaluate performance of communication channel. by using the simulation software to analyze the polsk communication system, the eye diagram of received signal is demonstrated in fig.(5) for fiber length 30km, 60km, and 90km respectively. fig.(5) show that the amplitude of received signal at fiber length of 30km is approximately four times the amplitude at fiber length of 60km. it can see that the eye diagram of the received signal at 90km length is worse as shown in fig.(5), the main reason for this being the influence of attenuation and polarization mode dispersion. 6. conclusion the investigations presented in this work focusing on 40 gbit/s based optical transmission systems with a polarization shift keying modulation. the optimization of the system settings is performed in 40 gbit/s single channel. the signal generation and transmission characteristics of polsk are introduced, and fundamental signal characteristics are explained. the use of polsk modulation format enables a significant improvement of nonlinear transmission characteristics at the cost of a slightly increased transmitter complexity used for the implementation of polarization modulation on conventional rz pulses as shown in fig.(5). in other words the transmission of data is valid for longer distance rather than using rz modulation format. the modulation formats employing polarization switching between consecutive pulses are identified as best solution for the performance enhancement in 40 gb/s single channel based transmission lines. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 132 simulation performance of a 40 gbit/s polarization shift keying system references 1. agrawal, g. p. "fiber-optic communication systems", john wiley, (new york), (2002). 2. chbat, d. p. and thiery, j. p. " the phase-shaped binary transmission (psbt): a new technique to transmitted far beyond the chromatic dispersion limit", ieee photon, trchnol. letter, vol.9, no.2, pp. 259-261, feb. 1997. 3. cheng, k. s. and conrad, j. "reduction of pulse-to-pulse interaction using alternative rz formats in 40gb/s system", ieee photonics technology letters, 14(1) (2002), 98-100. 4. edward collett,"field guide to polarization", spie press book, 2005. 5. hodzie, a. et. al., "10gb/s based nrz dwdm system using polarization switching", electronic letters 39(18) (2003), 1329-1330. 6. kaminor, i. and lieds, t. "optical fiber communications" academic press, 2002. 7. winzer, p. j., and essiambre, r.j, "advanced optical modulation formats", proceedings of the ieee, vol. 94 (2006), 952-985. 8. yariv, a. and yeh, p. "optical waves in crystals propagation and control of laser radiation" wiley classics library, 2003. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 133 w. y. hussen al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 134 simulation performance of a 40 gbit/s polarization shift keying system al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 135 w. y. hussen al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 136 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 158 optimization of hyperbolic tangent apodized chirped fiber bragg gratings (cfbg) for dispersion compensation in optical fiber communication muhammed faleh hassan, department of electrical engineering, college of engineering, kufa university, iraq (email: mufalh@yahoo.com) :abstract chirped fiber bragg grating is a promising approach for dispersion compensation in optical fiber communication systems, since it’s passive optical component, fiber compatible and has low insertion losses and low costs. unapodized cfbg is fail to achieve the expected performance due to high ripples in time delay response. many apodization profiles are suggested to optimize grating performance. among them, hyperbolic tangent (tanh) apodization profile result in overall superior performance. in this work, the reflection spectrum of cfbg is solved by numerical solution of reccati differential equation. results show that, the characteristics of the tanh apodized cfbg can varied systematically according to an angular tanh apodization profile parameter called truncation parameter (atr). by using this parameter the characteristics of the grating is assist in term of limitations of full-wave half maximum reflection bandwidth and minimizing average time-delay ripples for different truncation parameter values. results show that for a given chirped parameter value cfbg approach optimal performance at truncation parameter of 4. in optical communication bandwidth of 0.5nm cfbg can compensate linear dispersion of 100 km of standard optical fiber length, the required grating length is 10 cm. according to these results, the truncation parameter must be chosen carefully in performance optimization of the hyperbolic tanh apodized chirped fiber bragg grating. keywords: apodization, chirped fiber bragg grating, dispersion compensating grating, group-delay ripple. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 159 تحسين اداء محزز الحيود المقسم باستخدام صيغة تعديل الظل تمام لمعالجة التقزح في اتصاالت االلياف الضوئية جامعة الكوفة آلية الهندسةقسم الهندسة الكهربائية – محمد فالح حسن. م.م الخالصة وذلك , االلياف الضوئيةانظمة اتصاالت يعتبر محزز الحيود المقسم اسلوب واعد لالستخدام في تعديل ظاهرة التقزح في ير معدل في غفشل محزز الحيود المقسم ال. النه متالئم مع االلياف الضوئية و ذو توهين قليل للقدرة الضوئية مع آلفته المنخفضة من دوال وعلى هذا االساس تم اقتراح عدد. في الطيف الزاويوذلك بسبب وجود موثرات غير خطية , جو منهرتحقيق االداء الم ي هذا العمل حساب الطيف الترددي لمحزز فتم . الظل تمامصيغةمن بين هذه الدوال التي اعطت اداء منقطع النظير هي . التعديل خصائص ه يمكن تغييرالنتائج اشارت الى ان. رآاتي التفاضليةلطرق العددية لحل معادلةالحيود القسم وذلك باستخدام احدى ا حيث تم دراسة تاثير هذا العامل على خصائص محزز الحيود القسم من . م بتغير متغير يسمى عامل االنقاص تعديل الظل تماصيغة اشارت النتائج الى انه . آذلك تاثيره على النطاق الترددي لمحزز الحيود المقسمحيث تاثيره التذبذب الموجود في الطيف الزاوي لنظام اتصاالت .4ود المقسم الى افضل اداء له عند قيمة لعامل االنقاص مقدرها لعامل التقسيم يقترب محزز الحي معينةة معند قي 100 المتراآم في الليف الضوئي لمسافة التقزححزز الحيود المقسم من تعديليستطيع م , 0.5nmضوئي بطيف ترددي مقداره km . 10 بحيث ان طول محزز الحيود المطلوب هو cm . تظهر بوضوح الحاجة الى حساب , ج السابقةباالعتماد على النتائ .ك لتحسين اداء محزز القسم ذو صيغة تعديل الظل تماملعامل االنقاص بشكل دقيق وذ nomenclature )z(n : refractive index on : bragg grating refractive index λ : grating period l : grating length )z(θ : chirping function )z(f : apodization function c : chirping parameter 1v : foreword propagation wave 2v : backward propagation wave )z(q : complex coupling coefficient δ : phase shift per unit length bλ : bragg wavelength tra : truncation parameter effa : apodization parameter τ∆ : time delay ripples al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 160 introduction fiber bragg grating has emerged as important components in a varity of light wave applications. their unique filtering properties and versatility as in-fiber devices are illustrated by their use in wavelength stabilized laser, fiber lasers, remotely pumped amplifiers, raman amplifier, phase conjugators, converter, passive optical networks, wavelength division multiplexers/demultiplexers, add/drop multiplexer , gain equalizer and dispersion compensators. this last one can be achieved with a special fiber bragg grating type called chirped gratings. in chirped fiber bragg grating (cfbg) the period variation of the refraction index is not constant. gratings with linear variation are the ones with application for dispersion compensation [govid, 2005] , [govid, 2001]. light propagating within the fbg with a wavelength twice the grating period is reflected. used as a dispersion compensator, the grating period could be reduced linearly down the length of grating (i.e. chirped mode). therefore, the shorter wave-length is reflected at a point farther into the device than the longer wavelength. as , intramodal dispersion reflects the fact that the shorter (blue) wavelength of the optical pulse travel faster than the longer (red) wavelength, this wavelengthdependent time delay can be used to produce negative dispersion being perfect to compensate dispersion in optical telecommunications systems. using fiber bragg gratings for dispersion compensation is a promising approach, because they are passive optical components, fiber compatible, have low insertion losses and low costs. periodic or aperiodic fiber gratings with constant refractive index modulation depth (i.e., unapodized), however, show reflection spectra with large side lobes, and large amplitude ripples especially in cfbg as well as highly nonlinear dispersion characteristics which make them unsuitable for high-performance applications. these characteristics are attributed to residual multiple reflections at the grating ends and can be significantly suppressed by a suitable variation (apodization) of the modulation depth along its length [d. paster, 1996], [m. n. zervas, 1996],[r. i. laming]. the apodization requirements of aperiodic gratings (i.e. cfbg) are expected to be quite different to the ones of the periodic counterparts. it is already known that the reflection spectrum of an apodized, periodic standard grating follows closely the fourier transform of the applied apodization profile. as a result, smooth and tight apodization profiles result in enhanced side-lobe suppression and superior grating performance. various apodization profiles have been considered theoretically and experimentally in order to smoothen the reflection spectrum and linearize the dispersion al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 161 characteristics of aperiodic (chirped) gratings [m. n. zervas, 1996],[r. i. laming]. it has been realized that tight apodization profiles, in general, result in smooth features at the expense, however, of grating reflectivity, bandwidth, and dispersion. excessively tight apodization profiles, on the other hand, might unnecessarily truncate gratings (reduce their effective length) and, in some applications, could impose severe limitations in the writing process. in this paper, hyperbolic tangent apodization profile is studied and analyzed systematically. we study the effect of the angular truncation parameter of the tanh apodization profile on the cfbg performance. the study is directed in term of bandwidth limitation and linearized time delay characteristics, which make cfbg suitable for using in dispersion compensation applications. in section ii, of this paper fiber bragg grating model is presented, where reccati differential equation is solved using 4th order rung-kutta algorithm. section iii, explain and define the effect the truncation parameter of the tanh apodization profile on the cfbg characteristics. the main results of the present paper are discuss and compared in section iv. finally, section v gives the conclusion of the work. chirped fbg model wave propagation in optical fibers is analyzed by solving maxwell's equations with appropriate boundary conditions. many techniques are suggest for simulating fiber bragg gratings [l. poladian, 1993],[j. e. sipe, 1994],[johannes, 2000]. all the techniques have varying degrees of complexity. however, the simplest method is the straightforward numerical integration of the coupled-mode equations. in this contest, fiber bragg grating scattering of waves in a waveguide occurs when the refractive index is varying in the longitudinal direction .it can assume that the refractive index is varying as a quasi-sinusoidal function: ))( 2 cos()()( 0 zzzfnzn θ π + λ += (1) where, 0n is the fiber bragg grating reference index, )(zf is the apodization function and 2)2()( czz λ= πθ is the chirping function where, c (in m-1) is the chirp parameter and λ is the grating period. the functions )(zf and )(zθ are slowly varying compared to λ . if the fiber is in single mode operation, it supports only the fundamental mode, which has two components propagating in opposite directions. in the corrugated region, the forward propagating wave 1v and the backward propagating wave 2v are related by the coupled mode equations: al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 162 1 * 2 2 21 1 )( );( )( );( vzqvi dz zdv vzqvi dz zdv ++= +−= δ δ δ δ (2) in (2), 1v and 2v are the complex amplitude envelopes of the waves, obtained by removal of the spatial dependence )/ziexp( λ± π . )z(q is defined as the complex coupling coefficient ))(exp()( 2 )( 0 zizf n i zq θ π − λ − = (3) and δ is the phase shift per unit length compared to the bragg wavelength λ= 02nbλ . dz zdn b ))(( 2 12 0 θπ λ π ββδ − λ −=−= (4) we further define the local reflection coefficient as : );( );( );( 1 2 δ δ δρ zv zv z = (5) by calculating, dzdρ and substituting dzdv1 and dzdv2 from the coupled mode equation (2), we get the well-known riccati equation )()(2 *2 zqzqi dz d +−= ρδρ ρ (6) this differential equation can be numerically solved for the reflection coefficient ),0()( δρδ =r at the beginning of the grating of length l by using the 4th order runge–kutta and the boundary condition 0),( =δρ l . apodization of cfbgs fiber gratings are not infinite in length, so they have a beginning and an end. thus, they begin abruptly and end abruptly. the fourier transform of such a "rectangular" function immediately yields the well known sinc function, with its associated side-lobe structure apparent in al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 163 the reflection spectrum. the transform of a gaussian function, for example, is also a gaussian, with no side lobes. a grating with a similar refractive modulation amplitude profile diminishes the side lobes substantially. the suppression of the side lobes in the reflection spectrum by gradually increasing the coupling coefficient with penetration into, as well as gradually decreasing on exiting from the grating, is called apodization. many apodization profiles has been suggested to optimize cfbg characteristics, such as raised sine, sine, sinc, tanh and blackman profiles. karin [karin, 1998], studied the effect of these profiles on the chirped fiber grating characterstics, and established the optimum relation between the degree of the apodazation and the resulting interrelated grating characteristic. their results show that the hyperbolic-tangent apodazation profile results in overall superior performance, as it provide dispersion compensators with highly lineareized time delay characteristic with minimum reduction in linear dispersion, compared with the unapodized case. the hyperbolic tangent profiles can implement using the following equation. ⎩ ⎨ ⎧ ≤≤− ≤≤ = lzll)zl(atanh( lzlzatanh( )z(f tr tr 2 20 (7) where, the parameter atr is best to be called as truncation parameter, since it control the truncation of the apodization function and, l is the cfbg length. figure (1) shows tanh apodazation profile plot against grating length, for different truncation parameter (atr=1 to atr=20). from previous figure, it evidence that the truncation parameter play important role in optimizing in chirped grating characteristics i.e their effect on smoothing reflection response and linearized time delay characteristics with minimum reduction in linear dispersion. we define another parameter which is useful in our discussion is the apodization parameter effa [p. s. cross] : ∫ ∫ == l l eff dz dzzf area area a 0 0 )( fbg unapodized of fbg apodized of (8) the smaller the apodization parameter, the tighter the apodization profile. small apodization parameters correspond to small grating effective lengths. for unapodized gratings, 1=effa . in next section, we investigate the effect of the truncation parameter atr on the tanh apodized chirped fiber bragg grating characteristics, i.e. minimization unwanted time delay ripples τ∆ in phase response as well as it’s effects on the full-wave half maximum (fwhm) reflection bandwidth. figure (2) al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 164 shows the simulation steps that we are used in this work in the computation of the reflection spectrum of the hyperbolic tanh apodized linearly chirped fiber bragg grating. results in this work direct numerical integration method is used to solve non-linear reccati differential equation using 4th order runge-kutta method for reflection spectrum of cfbg. the cfbg parameter used in our simulation are as follow; fiber bragg grating length l=10cm, chirped parameter c=1e-2/m, optical center wavelength λb=1550nm, fiber grating refractive index n0=1.5. when the number of samples of coupling coefficient is small, it is necessary to include an interpolation routine to increase the number of samples in order to reduce the error in the runge– kutta algorithm. such an algorithm is implemented in matlab_7.4, yielding an efficient reflection spectrum calculation algorithm. the computation of a reflection spectrum takes about 20 minute for a “chirped” grating on a dual-core 1.8ghz and 512 mbyte ram. we first consider unapodized cfbg properties, i.e. magnitude and time-delay response. in this contest two condition are required for fiber bragg grating to be used as a perfect dispersion compensation device; first, the magnitude spectrum must be flat and second, the time delay characteristic must have negative linear dispersion slop adequate to compensate of fiber dispersion along define fiber length. figure (3a) and figure (3b) shows the magnitude and time delay characteristic of unapodized cfbg. it clearly that, the amplitude spectrum displays perfect flat response, while time-delay {figure (3b)} behavior of unapodized cfbg displays high unwanted ripples. hence these ripples make cfbg not suitable for optical communication applications, especially of using it as a dispersion compensator. figure (4a) shows the reflection spectrum of cfbg with hyperbolic tanh apodized profile for different truncation parameter {atr=1, 5, 10, 15 and 20}, the unapodized case is also shown for comparison. the value of atr=1 is not suitable for optical communication since, it cause high magnitude truncation and attenuation in reflection spectrum (compare with figure (1) ) .i.e minimizing the apodization parameter, and it shown here for comparison. it evidence that as truncation parameter increase, the cfbg 3db bandwidth increase (broaden) this result of increasing apodization parameter effa of the apodization function. the effect of the apodazation truncation parameter on the time delay linearization is shown, in figure (4b) for atr=20. from previous figures it clearly that the parameter atr play an important role in linearize time delay characteristics of the tanh apodized cfbg. hence, we try to study the effect of the varying truncation parameter on the removing unwanted ripples in time delay response as well as it’s limitation of the fwhm reflection bandwidth. figure (5) shows the full-wave half maximum al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 165 reflection bandwidth plotted against truncation parameter for different chirped parameter values. it noted that, sever reduction in fwhm reflection bandwidth occure at truncation parameter values of atr={1,2,3} especially for high chirped values i.e. c=1.5e-2/m. for example at c=1.5e-2/m, the percentage reduction in fwhm reflection bandwidth is 55%, 42% and 31% for truncation parameter of atr=1, 2 and 3 respectively. for atr>4 the apodization profiles have less pronounce effects on the reduction of fwhm reflection bandwidth. figure (6), show the average time delay ripples ∆τ plotted against truncation parameter for three different chirp parameter values. the average time delay ripple τ∆ is given by the mean value of the absolute difference of the actual time delays from the best fitted straight line. it cleary that, the average time delay ripples is exponentially related to chirped parameter value .i.e. the level of τ∆ become more sever for large chirped parameter values. hence, for each curve of figure (6), their, exist a point for truncation parameter value, at which the average time delay ripples is minimized (atr=4). again for atr>4 the time delay increase nearly linearly with atr, and become more sever for large atr values. according to these results, the truncation parameter must be set to value of 4 in performance optimization of the hyperbolic tangent apodized chirped fiber bragg grating. for example, for any value of chirped parameter, cfbg approach optimal performance at truncation parameter of 4. this results from that, the increasing in truncation parameter beyond atr=4, the full wave half maximum become broader and incorporate more ripples in reflection spectrum and hence, increasing the level of the average time delay ripples. in addition of using chirped fbg as dispersion compensation, it can be used as in line optical filter, that remove out of band amplified spontaneous emission (ase) noise and other transmission non-linearties. these two characteristics are studied and summarized in figure (7). the optical fiber compensating length in km and the fwhm reflection bandwidth are calculated against chirping parameter for tanh (atr=4) apodized cfbg. it evidence that as chirping parameter increase, fiber compensating length decrease exponentially (since the grating dispersion parameter is exponentially related to chirp parameter) while fwhm reflection bandwidth increases linearly. hence, it can optimize cfbg characteristics by choosing appropriate chirp parameter value. for single channel dispersion compensation and optical communication bandwidth of 0.5nm, using figure (7), chirp parameter must be set at c=0.002/m that resulting compensating fiber length of 100 km over standard fiber with dispersion parameter of {d=17ps/(nm.km)}, the required grating length is 10cm. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 166 conclusion the reflection spectrum and time delay characteristics of apodized linearly chirped fiber bragg grating have been studied and analyzed. the reflection spectrum of chirped grating is calculated by direct numerical integration of rccati differential equation yielding an efficient reflection spectrum calculation algorithm. it shown that the truncation parameter (a) of the hyperbolic tanh apodization profile can play an important rule in optimizing cfbg characteristics .i.e. minimum reduction in fwhm reflection bandwith and linearized time delay characteristics. a systematic study show that for any chirped parameter value, tanh apodized cfbg results in optimal performance at truncation parameter of 4. for single channel dispersion compensation and optical communication bandwidth of 0.5nm, 10cm grating length can compensating dispersion accumulated along fiber length of 100 km over standard fiber {d=17ps/(nm.km)}. it can concluded from these results, that for a given chirped parameter value, there exist a truncation parameter value at which cfbg approaches optimal performance. references d. pastor, j. capmany, d. ortega, v. tatay, and j. marti, “design of apodized linearly chirped fiber gratings for dispersion compensation,” j. lightwave technol., vol. 14, pp. 2581–2588, nov. 1996. govid p. agrawal, “lightwave technology telecommunication system”, john wily and sons, 2005. govind p. agrawal, “applications of nonlinear fiber optics ", academic press, 2001. j. e. sipe, l. poladian, and c. m. de sterke, “propagation through non-uniform grating structures,” j. opt. soc. amer. a, vol. 11, pp. 1307–1320, 1994. johannes skaar, "synthesis and characterization of fiber bragg gratings" , november, 7, 2000. karin ennser, mikhail n. zervas, and richard i. laming, " optimization of apodized linearly chirped fiber gratings for optical communications", ieee journal of quantum electronic, vol. 34, no. 5, pp.770-778, may 1998. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 167 l. poladian, “graphical and wkb analysis of nonuniform bragg gratings,” physic. rev. e, vol. 48, no. 6, pp. 4758–4767, 1993. m. n. zervas, k. ennser, and r. i. laming, “design of apodized linearly chirped fiber gratings for optical communications,” in proc. 22nd eur. conf. optical communications (ecoc 96), oslo, norway, 1996, vol. 3, pp. 233– 236. p. s. cross and h. kolgenik, “sidelobe suppression in corrugated waveguide filters,” opt. lett., vol. 1, pp. 43–45, 1977. r. i. laming, w. h. loh, m. j. cole, m. n. zervas, k. ennser, and v. gusmeroli, “fiber gratings for dispersion compensation,” in optical fiber communications (ofc 97) tech. dig., 1997, pp. 234–235. figure (1): hyperbolic tangent apodization profile for different truncation parameter values 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 normilazed cfbg length ta n h a m pl itu de atr=1 atr=20 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 168 start set the fbg characteristics; land,,n b 0 λλ∆ call the subroutine for linearly chirping of fbg using the chirping function ( )(zθ ) call the subroutine for apodized fbg using the tanh apodazation profile ( )(zf ).{note this subroutine is not used for unapodazed cfbg spectrum calculations} set the bandwidth resolution factor {this factor control the accuracy of resulting cfbg spectrum} solve eq.6 using one of the numerical techniques for solving differential equations end applying frequency domain measurements {calculate τ∆ } figure (2): flowchart for spectrum calculation of cfbg. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 169 1547 1548 1549 1550 1551 1552 1553 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 wavelength in nm p ow er r ef le ct iv ity figure (3a): power reflectivity versus wavelength of unapodized linearly chirped fbg 1548 1548.5 1549 1549.5 1550 1550.5 1551 1551.5 1552 0 200 400 600 800 1000 1200 wavelength in nm ti m e de la y in p s figure (3b): time delay response versus wavelength of unapodized linearly cfbg 1547 1548 1549 1550 1551 1552 1553 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 wavelength in nm p ow er r ef le ct iv ity atr=1 atr=5 atr=10 atr=15 atr=20 unapodized figure (4a): power reflectivity against wavelength for different truncation parameter values al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 170 1548.5 1549 1549.5 1550 1550.5 1551 1551.5 0 200 400 600 800 1000 1200 wavelength in nm p ow er r ef le ct iv ity unapodized atr=20 figure (4b): time delay response against wavelength for tanh (atr=20) apodized and unapodized cfbg (n or m al iz ed ) figure (6): average time delay ripples against truncation parameter for different chirped parameter values 0 2 4 6 8 10 12 14 16 18 20 0 1 2 3 4 5 6 7 8 x 10 -13 truncation parameter (atr) a ve ra ge ti m e de la y rip pl e in s ec on d c=10e-2 /m c=15e-2 /m c=20e-2 /m 0 2 4 6 8 10 12 14 16 18 20 0.5 1 1.5 2 2.5 3 3.5 4 4.5 truncation parameter (atr) fw h m r ef le ct io n b an dw id th c=0.5e-2/m c=1e-2/m c=1.5e-2/m figure (5): fwhm reflection bandwidth in nm against truncation parameter for different chirped parameter values in n m al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 171 0 0.005 0.01 0.015 0 20 40 60 80 100 120 140 160 fi be r c om pe ns at in g le ng th in k m 0 0.005 0.01 0.015 0 0.5 1 1.5 2 2.5 3 3.5 4 f w h m r ef le ct io n b an dw id th chirped parameter (c) figure (7): fiber compensating length in km and fwhm reflection bandwidth in nm against chirp parameter for tanh (atr=4) apodized cfbg al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 180 numerical solutions for potential flow pasts 2 – d lifting airfoils hayder aziz neema kufa university, faculty of engineering abstract the ability of the panel methods in solving the potential flow problem around 2-d lifting airfoils is tested in this study. the approximate solutions for potential flow pasts thick, thin, symmetrical, and non-symmetrical airfoils have been calculated by using panel methods and then compared with either the exact analytical solution or the numerical solution obtained by using a perturbation method. as a results, the linear-varying strength vortex method is seemed to be the better one in precision in solving the all four problems. األبعادحلول عددية لجريان جهدي حول سطوح رفع هوائية ثنائية حيدر عزيز نعمة جامعة الكوفة-الهندسة آلية تدريسي في الخالصة الحلول . األبعاد رفع هوائية ثنائية أسطحهذا البحث يفحص قابلية طرق الصفيحة في حل مشكلة الجريان الجهدي حول حسبت باستخدام طرق الصفيحة و من و غير متناظرة ةمتناظر هوائية سميكة و نحيفة و أسطحالتقريبية للجريان الجهدي حول آنتيجة نهائية طريقة الدوامة ذات الشدة . رابما مع الحل التحليلي الحقيقي او مع حل عددي باستخدام طريقة االضط ثم قورنت إ .األربعةالخطية بدت األحسن بالدقة في حل آل المسائل nomenclature pc pressure coefficient l.e leading edge t.e trailing edge c airfoil chord x horizontal coordinate α angle of attack ε thickness ratio subscripts i collocation point j singularity element n number of panels ∞ free stream al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 181 introduction due to the applicability of the results of the potential flow problem solution in airfoil design, this problem has received a good deal of attention. also, due to the phenomenal growth in the use of computers, a method that is valid for completely arbitrary geometry is needed. thus, panel methods have come to stay. in the panel methods the airfoil contour has been approximated by inscribed polygon. that is, the contour has been approximated by a number of straight-line segments. each segment is distributed by singularities of certain kind that have an undetermined strength. these singularities deflect the oncoming stream so that it will flow around the airfoil. the requirement the oncoming flow be tangent to every segment at a particular location ( collocation point ) gives a set of equations which is used to compute the singularities strength. thus the flow consisting of a uniform flow and the flow induced by the singularities on a finite number of segments becomes determined and the velocity and the pressure at any point in the flow field can be calculated. the requirement of the flow must be tangent to the segments at the collocation points leads to the normal component of the flow must be zero at these collocation points. this is the physical boundary condition (that is, the normal component of the fluid velocity must be zero on the solid boundaries). therefore, two boundary conditions can be used to solve the laplace's equation and they are; the neumann b. c. which utilizes the physical b. c. directly, and the dirichlet b. c. which specifies the velocity potential on the boundaries so that indirectly zero normal flow will be met. hess and smith [1] is a review of such methods. both source and vortex distributions have been used. the two-dimensional surface source method [1] approximates the body contour by an inscribed polygon. the number and distribution of the surface elements determine the accuracy of the numerical solution. the surface source strength is assumed to be constant on each element, and the zero normal velocity boundary condition is applied at the midpoint of each element (collocation point) to produce a set of linear algebraic equations for the values of the source strength on the elements. for lift problem an auxiliary constant-strength vortex singularity element has been distributed. the total strength of this distribution is adjusted to specify the kutta condition, which requires the equality of the surface pressures at the collocation points adjacent to the trailing edge. some difficulties have been encountered for airfoils that have very thin trailing edges. moreover, the difficulties have been made more severe by the use of the relatively small element numbers that are appropriate for the three-dimensional cases. even in the two-dimensional cases reduced element numbers are becoming more desirable to conserve computing time in multielement airfoil cases. one technique for increasing the computational accuracy is the so-called higher-order formulation, which is described in [2] for non-lifting case. while higher-order surface singularity distributions for lifting cases is described in [3]. formulation of the problem and its numerical solution the general problem of calculating the incompressible, 2-d potential flow requires the solution of laplace's equation ( 02 =φ∇ ) for the velocity potential φ , with boundary conditions of zero normal velocity component on all solid surfaces (vn=0), and zero velocity perturbation at large distances from the airfoil (v∞=constant). auxiliary conditions (kutta conditions) are also imposed to fix the value of the circulation about the airfoils. the numerical solution can be constructed by six ordinary steps, and they are: 1-selection of the singularity element. the first and one of the most important decisions is the type of singularity element or elements that will be used. this includes the selection of source, doublet, or vortex representation and the method of discretizing these distributions (constant, linear, or quadratic). six singularity distributions have been used in this study and they are; constantstrength doublet, constant-strength vortex, combined constant-strength source and doublet, linearvarying strength doublet, linear-varying strength vortex, and quadratic-varying strength doublet and for more details it is preferred to return to [4]. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 182 2-descritization of geometry. once the basic solution element is selected, the geometry of the problem has to be subdivided such that it will consist of those basic solution elements. in this generation process, the elements’ end points and the collocation points are defined. the collocation points are points where the boundary conditions, such as the zero normal flow to a solid surface, will be enforced. 3influence coefficients. the influence coefficient ija is the normal component of the flow velocity induced by a unit strength element j at a collocation point i. in this phase, for each of the elements an algebraic equation (based on the boundary condition) is derived at the collocation point. 4establish the righthand side (rhs). the rhs of the matrix equation is the known portion of the free-stream velocity or the potential and requires mainly the computation of geometric quantities. 5solve linear set of equations. the influence coefficients and the rhs equations are obtained in the previous steps and now the equations are solved by a standard matrix technique (gausselimination technique). 6secondary computations. the solution of the matrix equation results in the singularity strengths and the velocity field and any secondary information can be computed. the pressure will be computed by the bernoulli’s equation, and the loads and the aerodynamic coefficients will be computed by adding up the contributions of the elements. actually the results of the first four steps mentioned above is the following system: ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ = ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ n 2 1 n 2 1 nnn3n2n1 2n232221 1n131211 rhs . . rhs rhs σ . . σ σ ...aaaa . . ...aaaa ....aaaa where aij is the influence coefficient j σ is the singularity unknown strength the above system of equation have been solved by using the guassian elimination method for j σ fortran 77 programming language have been used to solved the problem, just few second have been consumed to get upon the final results. the airfoils used in the study four types of airfoils were used in this study in solving the thickness, thinness, symmetry, and non-symmetry problems and they are: a-van de vooren airfoil with non-cusped trailing edge: to illustrate the effectiveness of the methods used in solving the problem for ordinary shapes of airfoils with finite trailing edge angles. non-cusped t.e l.e al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 183 bvan de vooren airfoil with cusped trailing edge: to illustrate the effectiveness of the methods used in solving the problem for ordinary shapes of airfoils with zero trailing edge angles. csymmetric joukowski airfoil: to illustrate the effectiveness of the methods used in solving the problem for thin airfoils with cusped trailing edge. dcambered joukowski airfoil: to illustrate the effectiveness of the methods used in solving the problem of camber for thin airfoils with cusped trailing edge. numerical results and discussion the pressure distribution for the seven surface singularity methods on a thick van de voorn airfoil with non-cusped trailing edge and with cusped trailing edge are shown in fig. (1) and fig. (2) respectively. the agreement between the analytical solution [5] and the numerical solution of the panel methods for the first case is excellent as shown in fig. (1) espcialy for (n=60). that is due to the collocation points position be near the surface area of the airfoil where the analytical solution have been calculated (i.e, in the panal method, the collocation points are some where inside the airfoil counter and they will be nearest to the airfoil counter as the number of the used panel have been increased). some deviation of the numerical solutions from the analytical solution appears near the trailing edge as shown in fig. (2), and that is due to the very thin region there (cusped) and a very high interaction of adjacent singularities will appear. depending on the earlier results, the pressure distributions for two surface singularity methods on thin symmetrical and non-symmetrical (cambered) airfoils are shown in fig. (3) and fig. n(4) respectively. generally, very good agreement between the solutions obtained by these methods and the solutions obtained by method of [6]. cusped t.e non-cusped t.e cusped t.e camber line al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 184 conclusions 1-the methods depending upon the dirichlet b.c. are better than the methods depending upon the neumann b.c. in the solution of the potential flow around thick airfoils without cusped trailing edges, especially the constant-strength doublet method because of the ease construction, low computational effort, and good results even for low density of panels. 2-the linear-varying strength vortex method with the neumann b.c. and the constant-strength doublet, combined constant-strength source and doublet, and quadratic-varying strength doublet methods with dirichlet b.c. can be used to solve the potential flow problem around symmetric thick and thin airfoils with cusped trailing edges. but only the linear-varying strength vortex method with neumann b.c. and the combined constant-strength source and doublet method with dirichlet b.c. can be used to solve the potential flow problem around asymmetric and thin airfoils with cusped trailing edges. 3-from the above conclusions, the decision of the type of the elementary solution distribution and the boundary condition selection depends upon the case under testing. eferencesr 1. j. l. hess and a. m. o. smith, “ calculation of potential flow about arbitrary bodies,”in: prog. in aeronautical sciences 8(pergamon, new york, 1966). 2. j. l. hess, “ higher-order numerical solution of the integral equation for 2-d neumann problem,” computer methods in applied mechanics and engineering 2 (1973) 1-15. 3. j. l. hess, “ the use of higher-order surface singularity distribution to obtain improved potential flow solutions for 2-d lifting airfoils,” computer methods in applied mechanics and engineering 5 (1975) 11-35. 4. aimen r. noor, “ the use of panel method in the prediction of the potential flow around 2-d configurations,” m.sc. thesis, babylon university, 2001. 5. j. katz, and a. poltkin, “low-speed aerodynamics from wing theory to panel methods,” mc graw hill, inc. 1998. 6. t. c. wong, c. h. liu, and j. geer,“ comparison of uniform perturbation and numerical solutions for some potential flows past slender bodies,” computers & fluids, vol. 13, no. 3, pp. 271-283, 1985. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 185 (g) fig. 1 pressure coefficient distribution for a 15% thick van de vooren airfoil with noncusped trailing edge at an angle of attack (α) of 5ο. (c) linear-varying strength doublet method with dirichlet b.c. analytical solution 10 panels 30 panels 60 panels 0.0 0.5 1.0 -1.8 -1.5 -1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2 0.0 0.5 1.0 x/c -1.8 -1.5 -1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2 cp x/c x/c 0.0 0.5 1.0 x/c -1.8 -1.5 -1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2 cp constant-strength doublet method with neumann b.c. constant-strength vortex method with neumann b.c. linear-varying strength vortex method with neumann b.c. (a) combined constant-strength source and doublet method with dirichlet b.c. (b) constant-strength doublet method with dirichlet b.c. (d) (e) (f) quadratic-varying strength doublet method with dirichlet b.c. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 186 (g) fig. 2 pressure coefficient distribution for a 15 % thick van de vooren airfoil with cusped trailing edge at an angle of attack (α) of 5ο. 0.0 0.5 1.0 x/c -1.9 -1.6 -1.3 -1.0 -0.7 -0.4 -0.1 0.2 0.5 0.8 1.1 cp 0.0 0.5 1.0 x/c 0.0 0.5 1.0 x/c 0.0 0.5 1.0 x/c -1.9 -1.6 -1.3 -1.0 -0.7 -0.4 -0.1 0.2 0.5 0.8 1.1 cp 0.0 0.5 1.0 x/c 0.0 0.5 1.0 x/c 0.0 0.5 1.0 x/c -1.9 -1.6 -1.3 -1.0 -0.7 -0.4 -0.1 0.2 0.5 0.8 1.1 cp analytical solution 40 panels 60 panels constant-strength doublet method with neumann b.c. constant-strength vortex method with neumann b.c. linear-varying strength vortex method with neumann b.c. (a) combined constant-strength source and doublet method with dirichlet b.c. (b) constant-strength doublet method with dirichlet b.c. (c) linear-varying strength doublet method with dirichlet b.c. (d) (e) (f) quadratic-varying strength doublet method with dirichlet b.c. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 187 (a) (b) fig. 3 pressure coefficient distribution for a thin (ε = 0.01624) and symmetric joukowski airfoil with cusped trailing edge at α = 6ο. (a) (b) fig. 4 pressure coefficient distribution for a thin (ε = 0.02688) and cambered joukowski airfoil with cusped trailing edge at α = 0ο. 0.0 0.5 1.0 x/c -7.0 -5.0 -3.0 -1.0 1.0 cp 0.0 0.5 1.0 x/c -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 cp 0.0 0.5 1.0 x/c -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 1.0 cp 0.0 0.5 1.0 x/c -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 cp perturbation method 40 panels 50 panels 60 panelslinear-varying strength vortex method with neumann b.c. combined constant-strength source and doublet method with dirichlet b.c. quadratic-varying strength doublet method with dirichlet b.c. constant-strength doublet method with dirichlet b.c perturbation method 40 panels 50 panels 60 panels linear-varying strength vortex method with neumann b.c. combined constant-strength source and doublet method with dirichlet b.c. quadratic-varying strength doublet method with dirichlet b.c. constant-strength doublet method with dirichlet b.c <4d6963726f736f667420576f7264202d203120202020202020cdedcfd120e3e5cfed20c8c7ded12dc7e1dfe1edc920c7e1cadee4edc92dc8dbcfc7cf> al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 1 experimental study of a typical iraqi wall thermal performance with q-bond insulation in winter conditions hayder mahdi baker /msc. mechanical engineering assist lecturer/foundation of technical education/ technical –college baghdad abstract in this work, an experimental study was designed and conducted to investigate the effect of using q-bond panels on a typical wall at iraqi local winter conditions. the q-bond panel's dimensions were 1 m2 x 3 mm thickness. an air gap of 5cm is made between the wall and q-bond panel. a through temperature measurements were made on both sides of the wall with and without using q-bond panel all over 10 hours for different weather conditions (sunny , partly clouded and runny days) on 2 , 5 , and 16 december 2010 respectively, and also for complete two days (24 hours) on 23-24 december 2010(sunny days). a point located in the middle of the wall face was found to be the most representative. the measured amplitude of the inside wall temperature variation with q-bond was less than that for the same wall without the q-bond. nomencluchers t1 outside wall temperature t2 air gap temperature t3 inside wall temperature t4 atmosphere temperature in shadow n sequence points kx nx amplitude amplitude nw frequency j complex number k number of sequence points دراسة عملية الداء عزل لنموذج جدارعراقي باستخدام عازل الكيوبوند في ظروف الشتاء طاقة حرارية/ماجستير هندسة ميكانيكية/حيدر مهدي باقر بغداد-الكلية التقنية/هيئة التعليم التقني / مدرس مساعد الموجز م فــي تغليــف الجــداران فــي عــازل الكيــو بونــد المســتخد الســتخدامدراســة عمليــة إجــراءتــم فــي هــذا البحــث ٢م ١ بإبعــاد عــازل الكيــو بونــد اســتخدامتــم . لتقليــل الحمــل الحــراري المفقــود مــن خــالل الجــدارظــروف الشــتاء قـراءة درجـات تمـت.سـم ٥هوائي بين عازل الكيو بوند و الجـدار بمقـدار م عمل فراغت. ملم ٣وبسمك مقداره ســـاعات ١٠ بحـــالتين باســـتخدام عـــازل الكيـــو بونـــد وبدونـــه لمـــدةالجـــدار الحــرارة الداخليـــة والخارجيـــة علـــى جـــانبي al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 2 على التوالي ٢٠١٠-١٢-١٦، ٥، ٢اليام ) ممطر غائم جزئي و غائم، صحومشمس (لظروف مناخية مختلفة نقطــة للقــراءات وجــدت أفضــل. )مشــمس صــحو( ٢٠١٠-١٢٢٤و ٢٣ســاعة ليــومي ٢٤ و كــذلك لمــدة ، اقـل بالمقارنـة الموجـة لدرجـة الحـرارة الداخليـة للجـدار باسـتخدام عـازل الكيـو بونـد قمـة . الحـائط وجه في منتصف .الدورة بالساعةالموجة لدرجة الحرارة الداخلية للجدار بدون استخدام عازل الكيو بوند لنفس تردد قمة مع introduction thermal insulation is an essential part of almost all buildings since it gives many advantages. human race lives in a hostile environment. the degree of hostility varies from season to season and with the geographical area. for this reason mankind has to provide a comfortable environment for his living. in cold climate for example, heat should be added to the room to make the environment suitable for human comfort [٢]. thermal insulations normally consist of the following basic materials and composites:: inorganic, fibrous, or cellular aterials such as glass, rock, or slag wool; and calcium silicate, bonded perlite, vermiculite, and ceramic products. asbestos insulations used to be applied, but asbestos has been shown to be a carcinogen. extreme caution must be used if it is encountered [٤] thermal resistance of an enclosed airspace ra has a significant effect on the total thermal resistance rt of the building envelope, especially when the value of rt is low. thermal resistance ra depends on the characteristic of the surface (reflective or non reflective), the mean temperature, the temperature difference of the surfaces perpendicular to heat flow, the width across the airspace along the heat flow, and the direction of airflow[١٠]. as the air cavity between the wall leaves or the roof and ceiling increases so does the degree of noise reduction. this concept is similar with other building elements such as double glazed windows. where double glazing is also used for thermal efficiency the size of the air cavity may be determined by the required level of thermal efficiency as increasing the cavity size decreases the thermal effectiveness of the glazing. (boeran, 1971) [٦] used the matrix method to calculate the solar heat gain through roofs and walls , under assumption that both solar radiation and external temperature go daily through a similar period cycle , and that this cycle was periodic sinusoidal for both quantities. (thomas w. petrie, 2001) [١١] results are given from a field investigation of side-by-side houses in knoxville,tennessee. the houses were identical except one had insulating concrete form (icf) exterior. (g. baldinelli, 2010) [٧] walls and the other had conventional wood-framed exterior walls. an outdoor experimental apparatus (a structure) was built combining in situ environmental conditions with common laboratory setups; the purpose is that of evaluating the ‘‘in situ’’ thermo physical properties (stationary and dynamic) of the radiant barrier-air gap system alone in vertical walls. measurements were done in central italy, during the summer, on the hottest days of july and august, thus exposing surveys to strongly variable outdoor conditions. (salihuddin radin sumadi, 2008)[٩] the development and construction of lightweight pre-fabricated sandwich structural elements in building construction is a growing trend in construction industry all over the world due to its high strength-to-weight ratio, reduced weight, and good thermal insulation characteristics. sandwich construction element consists of thin face sheets or encasement of high performance material and a thick, lightweight and low strength material as core. ferrocement is regarded as highly versatile thin material possessing superior properties which cannot be matched by other conventional thin materials. (a abela, 2006) [١] investigate and study how insulating materials used in local construction methods may enhance the thermal performance of a typical maltese building envelope. the study provides a practical insight on how various insulation options within the cavity of a globigerina limestone and concrete block work wall affects the u-value of the wall. this study investigates insulation materials such as expanded polystyrene, stone wool, glass wool with/without a reflective coating. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 3 (ammar bouchair, 2008) [٣] investigates the analytical assessment of the insulation capacity of external cavity walls made with different arrangements of holes with and without insulation material. the thermal analysis of the different fired clay hollow bricks was carried out using a steady state model which was developed by the author. the minimum width of cavity in cavity wall construction which is acoustically beneficial is 50mm. wider cavities will improve low frequency performance. increasing the size of a cavity also allows thicker acoustic insulation to be installed, achieving an increased level of sound insulation. it is important to note that there is no maximum cavity width for brick veneer walling however cavity wall construction has a maximum of 65 mm. [٥] experimental work the wall is constructed from common brick. an iron frame made from square iron pipe of 5cm * 5cm cross sectional area is riveted to the wall. the q-bond insulation (which is consists from layers of aluminum and rubber) is riveted to the iron frame producing an air gap between the qbond insulation and the wall. the surface area of the whole construction is 1 m2. the temperature readings were taken for four points lined on the center line of the wall for both cases (with and without qbond thermal insulation). the measurement were made at the outside (t1), air gap (t2), and inside wall faces (t3) as shown in figure 1. temperature readings were taking for 10 hours for different weather conditions (sunny, partly clouded and runny days) on 2, 5, and 16 december 2010 respectively. by comparing the results between the four points the variation was found small and can be neglected. hence; point (2) was chosen as a representation through out a measurements made during rain, sunny, and partially clouded days as figures 2 to 5. these readings showed that the center point can be practically chosen to predict the performance since it is sufficiently far from edges and less affected by dimensionality. after these preparations, the readings of point (2) for (24) hours with and without q-bond on 23 to 24-december -2010 (sunny day) were conducted. since the temperature variations have cyclic nature, the fast fourier transform algorithms (fft) [٨] was used to analyze the results obtained for two cases with and without using q-bond thermal insulation by using microsoft excel to solve the equations of (fft) as shown below: 1. the dft of an n-point sequence {xk} is defined as: 1,......,2,1,0, 1 0 /2 −== ∑ − = π− nkexx n n nknj nk (1) 2. the inverse dft of the sequence {xn} is given by: 1,......,2,1,0, 1 1 0 /2 −== ∑ − = π nnex n x n k nnkj kn (2) these are often written in terms of njn ew /2π−= results and discussion figure 10 shows the change in frequency cycle per hour with amplitude (0c) for case without using q-bond thermal insulation for the three reading temperatures outside wall temperature (t1) and inside wall temperature (t2) and shadow wall temperature (t3) while figure 11 shows the change in frequency cycle per hour with amplitude (0c) for case with using q-bond thermal insulation for the four reading temperatures outside wall temperature (t1) , air gap temperature (t2) , inside wall temperature (t3) and shadow wall temperature (t4) as shown in figure 11 to 13. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 4 it can be seen from figure 12 the amplitude of the inside wall temperature using q-bond thermal insulation have a magnitude lower than the magnitude of inside wall temperature without using the q-bond thermal insulation for the same frequency cycle /hour of about 0.04 . that means the better performance of using q-bond thermal insulation and its ability to make good insulation for building and the absorbed heat will be stored in air gap and then passed through the outside wall. a comparison was made between the sunny day, runny and clouded, and partly clouded day after analyzing its results by using (fft) the results were shown in figures 14 to 17. conclusions from results above it can be list the following: 1. q-bond panel has a great thermal resistance 2. its ability to reflect most of the solar gain and this is the best in summer conditions and decrease the heat loss from buildings in winter conditions 3. easy to fixed on building 4. available in different colors refrences 1. a abela , thermal performance of insulation samples: applications for malta , university of malta – june 2006. 2. abdul hadi nema khalifu, housing design strategies for hot arid zones, department of mechanical engineering, university of technology ,iraq,2000 ٣. ammar bouchair , a parametric study of the thermal insulation of external cavity wall constructed using fired clay hollow bricks , proceedings of the 4th iasme / wseas international conference on energy & environment (ee'09) , 2008. ٤. ashrae handbook – fundamentals, 1997 5. australian/new zealand standard 2107 “acoustics – recommended design sound levels and reverberation times for building interiors”, 2000 6. de boer. s.h. and euser. p. r' calculation of the solar heat gain through composite construction by the matrix method" heat transfer ,international institute of refrigeration p.93-100, 1971 7. g. baldinelli "a methodology for experimental evaluations of low-e barriers thermal properties: field tests and comparison with theoretical models "building and environment ,vol .45, pp.1016-1024 , 2010. 8. rodger e., signals and systems continuous and discrete ,prentice hall, united states of america , 1998 9. salihuddin radin sumadi , mahyuddin ramli , development of lightweight ferrocement sandwich panels for modular housing and industralized building system , internet , 2008. ١٠. 10. shan k. wang, handbook of air conditioning and refrigeration, mcgraw-hill , new york, 2001 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 5 11. thomas w. petrie, how insulating concrete form vs. conventional construction of exterior walls affects whole building energy consumption: results from a field study and simulation of side-by-side houses, internet, 2001. figure 2 variation of temperature with time for a sunny day figure 3 variation of temperature with time for a sunny day al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 6 figure 4 variation of temperature with time for a sunny day figure 5 variation of temperature with time for a sunny day figure 6 variation of temperature with time for a partly clouded day al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 7 figure 7 variation of temperature with time for a runny day figure 8 variation of temperature with time for sunny with q-bond figure 9 variation of temperature with time for sunny without q-bond al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 8 figure 10 comparison between in side wall temperature (t3) in two cases with and without qbond for (24) hours. figure 11 change in frequency cycle per hour with amplitude (0c) for case without using q-bond thermal insulation for 24 hours figure 12 change in frequency cycle per hour with amplitude (0c) for case with using q-bond thermal insulation for 24 hours al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 9 figure 13 a comparison between the inside wall temperatures with and without using q-bond thermal insulation for 24 hours figure 14 change in frequency cycle per hour with amplitude (0c) for case with using q-bond thermal insulation for 10 hours for runny day figure 15 change in frequency cycle per hour with amplitude (0c) for case with using q-bond thermal insulation for 10 hours for partly clouded day al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 10 figure 16 change in frequency cycle per hour with amplitude (0c) for case with using q-bond thermal insulation for 10 hours for sunny day figure 17 a comparison between the inside wall temperatures with using q-bond thermal insulation for 24 hours for three cases al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012 347 dual band microstrip antenna with slit load design for wireless local area network application asst. lect. basim khalaf jarulla al-mustansiriya university, college of engineering, electrical engineering department, email:basimkalaf@yahoo.com asst. lect. izz kadhum abboud al-mustansiriya university, college of engineering, computer & software department, email:izz1962@yahoo.com asst. lect. wail ibrahim khalil al-mustansiriya university, college of engineering, electrical engineering department email:wailalazawy@yahoo.com abstract this paper presents a design of dual frequency band operation nearly square patch antenna for ieee 802.11b,g (2.4ghz-2.4835ghz) and ieee 802.11a (5.15ghz-5.25ghz)by using a patch antenna. the patch and ground plane are separated by a substrate; the radiating patch have two pairs of orthogonal slits cut from the edge, this antenna has wide bandwidth in the frequency band of (wlan) and with a return loss ≤ −10 db from 2.4 ghz to 2.48 ghz and from 5.12 ghz to 5.32 ghz exhibits circularly polarized far field radiation pattern. the proposed antennas have been simulated and analyzed using method of moments (mom) based software package microwave office 2009 v9.0. the results show that the antenna has dual band frequency operation by using slit load. keywords: ieee802.11a/b/g, microstrip antenna, dual band, slit load, circular polarization. دة المنتظمة لتطبیقات تصمیم ھوائي الشریحة الدقیقة مزدوج الحزمة باستحدام الفتحات المتعام البث االسلكي المحلي )رس مساعدمد ( جاراهللا خلفباسم قسم ، كلیة الھندسة، الجامعة المستنصرسة الھندسة الكھربائیة email:basimkalaf@yahoo.com ) مدرس مساعد(عز كاظم عبود قسم ، كلیة الھندسة، الجامعة المستنصرسة ھندسة الحاسبات والبرمجیات email:izz1962@yahoo.com )مدرس مساعد(وائل ابراھیم خلیل قسم ، كلیة الھندسة، الجامعة المستنصرسة الھندسة الكھربائیة email:wailalazawy@yahoo.com basim khalaf jarulla, izz kadhum abboud and wail ibrahim khalil al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012348 (ieee 802.11b,g) (ieee802.11a) (ieee 802.11b,g) (ieee802.11a) 3 db 2009 1. introduction microstrip antenna is a type of antennas which can be used for transmitting and receiving signals. microstrip or printed antennas are low profile, small size, light weight and widely used in wireless and mobile communications, as well as radar applications. microstrip antennas can be divided into two basic types by structure, namely microstrip patch antenna and microstrip slot antenna. the microstrip patch antennas can be fed by microstrip line and coaxial probe (kueathawikun1, 2006). recently, wireless local area network (wlan) has received much attention for the flexibility of network reconfiguration in office room, mobile internet connection and so on. a wlan provides all the benefits of traditional lan technologies without the limitations of being tethered to a cable. this provides greatly increased freedom and flexibility (jim, 2002). there are many commercial wlan devices in the markets which use 2.4ghz frequency band supporting the speed of 11mbps. and the demand for faster data communication made consideration of using 5ghz frequency band instead of 2.4ghz frequency band which is widely used as ieee 802.11b. there are three frequency bands for ieee 802.11a, which are 5.15ghz ~ 5.25ghz, 5.25ghz ~ 5.35ghz, 5.725ghz ~ 5.825ghz. the ieee 802.11a standard defines operation at up to 54mbps. so, it would be very convenient if we have an antenna which can be applied to 2.4ghz and 5ghz operations with suitable gains (woon, 2002). this proposed microstrip antenna designed to utilized in 2.4-2.4835 ghz and 5.7255.825ghz frequency ranges (ieee 802.11 b/g/a), fed by 50ω standard miniature adapter (sma). 2the proposed antenna: 2.1-rectangular microstrip patch antenna: the antenna configuration is rectangular microstrip patch antenna shown in fig.l. in this case the circular polarization (cp) is obtained because the two modes of resonance (corresponding to the adjacent sides of the rectangle), are spatially orthogonal. the antenna is excited at a frequency in between the resonant frequencies of these two modes in order to obtain the phase quadrature relationship between the voltages (and therefore magnetic currents) of two modes. corner or diagonal feeding is required to allow both the modes to be excited with a single feed (sharma, 1983). the ratio of the two orthogonal dimensions w/l should be generally in the range of (1.01– 1.10) depending upon the substrate parameters. when the patch is fed along the diagonal, then the two resonance modes corresponding to lengths l and w are spatially orthogonal. the cp is dual band microstrip antenna with slit load design for wireless local area network application 349al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012 obtained at a frequency, which lies between the resonance frequencies of these two modes, where the two orthogonal modes have equal magnitude and are in phase quadrature (kumar, 2003). this kind of design is the simplest form to generated circular polarization and is very suitable for the wlan rhcp or lhcp microstrip antenna design (basim, 2011). 2.2-rectangular patch with slits: by embedding suitable slots in the radiating patch, compact operation of microstrip antennas can be obtained. figure 2 shows slotted patch suitable for the design of compact microstrip antenna. in this figure, the embedded slot is a cross slot, whose two orthogonal arms can be of unequal (iwasaki, 1996; jawad, 2008) or equal lengths (wong, 1997; kin-lu, 2002). the use of four inserted slits at the patch edges of a rectangular patch [30] has been shown to be a promising compact dual-frequency design. the antenna design is shown in fig2. the four inserted slits are of equal length l and narrow width 1 mm (kin-lu, 2002) this kind of slotted patch causes meandering of the patch surface current path in two orthogonal directions and is suitable for achieving compact circularly polarized radiation or compact dual-frequency operation with orthogonal polarizations (yang, 1998). the basic idea of the proposed antenna structure has been extracted from a comparative study of both the conventional square patch antenna, fig. 1, and the square microstrip antenna with two pairs of orthogonal slits at the edges, fig. 2 (qais, 2005). the presence of slits in this antenna is a way to increase the surface current path length compared with that of the conventional square patch antenna, fig. 1a, resulting in a reduced resonant frequency or a reduced size antenna if the design frequency is to maintained. it had been found that this antenna structure provides a reduction in size of about 40% (jawad, 2008). in the present work, further increase in the slit lengths has been proposed in an attempt to gain further size reduction of the resulting structure as compared to the patch structures cited in fig. 1 and 2. the dimensions of slots have been optimized to meet the 802.11b/g/a antenna design requirements. a single 50 ω probe feed has been used to support producing the rhcp or lhcp requirement of the 802.11b/g/a antenna radiation pattern (jawad, 2008). 3the proposed antenna design: the calculation of the square microstrip antenna length is based on transmission-line model (bahi, 1980) the width w of the radiating edge, which is not critical, chosen first. the length l is slightly less than a half wavelength in the dielectric. the precise value of the dimension l of the square patch has been calculated using expression (amamam, 1997). (1) where the effective dielectric constant, and ∆l is the fringe factor (balanis, 1997). for the frequency of 5.25 ghz and using (fr-4) with a relative dielectric constant of 4.2 and loss tangent of 0.017, with substrate height of 1.575 mm, this yields nearly square patch antenna length fig. 1, of l=15.38 mm and w=16.11 mm. the ratio of the two orthogonal dimensions w/l is 1.047, lies in the range of generating two spatially orthogonal resonance modes (iwasaki, 1996). the feed-point of the antenna, it is defined in terms of input impedance zin of the antenna and the characteristic impedance zo of the feed line. the feed point position should be placed at the location where the input impedance of the antenna matches the characteristic impedance of the feed (iwasaki, 1996). the patch can be fed by a coax line from underneath. the impedance varies from zero in the center to the edge resistance approximately as (thomas, 2005). basim khalaf jarulla, izz kadhum abboud and wail ibrahim khalil al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012350 (2) where ri is the input resistance, re the input resistance at the edge, and x the distance from the patch center. by shifting the feed-point along the diagonal to x =-0.4875 cm and y = -0.475 cm, from the center of the patch; a perfect match with a 50ω feed line is obtained. the feeding point position is 0.323% from the diagonal long (basim, 1996). the slit lengths of the antenna in fig. 2 are tuned to the resonance (design) frequency in the x and y-directions and are set to result in a value of about 7.5 mm, with a slot width a of 1 mm. this results in a patch length of the antenna structure of fig. 2 to be l = 22.90 mm, using the same substrate. the resulting size reduction offered by this antenna is of about 35% as compared with the conventional nearly square microstrip antenna (jawad, 2008) the proposed antenna structure has been modeled using a full-wave numerical method of moment (mom). emsighttm, of the applied wave research (awr), includes a full-wave electromagnetic solver that uses a modified spectral domain method of moments to accurately determine the multi-port scattering parameters for predominately planar structures (awr, 2009). in the presented design; this software package was applied to simulate the typical characteristic of the proposed antennas. 4simulation results: the proposed antenna structure had been modeled at the design frequencies of the ieee 802.11b/g/a. it has been supposed that the antenna element to be located parallel to x-y plane and centered at the origin (0, 0, 0). the computed input return losses of the antenna patch is shown in fig. 3. e-plane and h-plane rhcp and lhcp radiation patterns at the ieee 802.11b/g frequency of 2.45 ghz are shown in fig. 4a, where e-plane and h-plane rhcp and lhcp radiation patterns at the ieee 802.11a frequency of 5.21 ghz are shown in fig. 4b. it is clear that this antenna supports the required rhcp electric field radiation pattern. the resulting axial ratio as a function of frequency is depicted in fig. 5. it can be seen that the axial ratio in the broadside direction is below 3 db. the computed gain around the ieee802.11b/g and ieee802.11a has 7 db and 5 db respectively. as the gain response implies, the proposed antenna possesses an average gain of about more than 4 db throughout the required bandwidths of ieee802.11b/g/a antenna. 5conclusions: a nearly square dual-band single probe-fed microstrip patch antenna with four inserted slits at the patch edges has been investigated. the realized impedance bandwidths (return loss ≤ −10 db) and the circular polarization bandwidth (axial ratio ≤ 3 db) satisfy the bandwidth requirements for the ieee802.11b/g/a operation. 6refences: 1. awr ® design environment, microwave office ® (mwo) 2009 v9. 1960 e. grand avenue, suite 430 el segundo, ca 90245 usa 2. bahi, and bhartia, “microstrip antennas”, artech house, inc. 1980. 3. basim k. jarulla, “circularly polarized microstrip antenna with reactive load design for wireless local area network application”, journal of engineering and development,vol.15, no.4, 2011. 4. c. a. balanis, “antenna theory, analysis and design”, john wiley & sons 1997. dual band microstrip antenna with slit load design for wireless local area network application 351al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012 5. c. sharma and kuldip c. gupta, “analysis and optimized design of single feed circularly polarized microstrip antenna,” ieee transactions on antennas and propagation, vol. ap-31, no.6, november 1983. 6. g. kumar and k. p. ray, “broadband microstrip antennas”, artech house, inc. 2003. 7. h. iwasaki, “a circularly polarized small-size microstrip antenna with a cross slot,” ieee. trans. antennas propagat. 44, 1399–1401, oct. 1996. 8. jawad k. ali, “a new compact size microstrip patch antenna with irregular slots for handheld gps application”, eng. & technology, vol.26, no.10, 2008. 9. jim feier, “wireless lans”, sams, 2002. 10. kin-lu wong, “compact and broadband microstrip antennas”. john wiley & sons 2002. 11. k. l. wong and k. p. yang, “small dual-frequency microstrip antenna with cross slot,” electron. lett. 33, 1916– 1917, nov. 6, 1997. 12. k. p. yang and k. l. wong, “inclined-slot-coupled compact dual frequency microstrip antenna with cross-slot,” electron. lett. 34, 321–322, feb. 19, 1998. 13. m. amamam, “design of rectangular microstrip patch antenna for 2.4 ghz band”, applied microwave and wireless nov/dec 1997. 14. qais k. shakir, “investigation, design, and simulation of microstrip antenna for gps applications”, m.sc. thesis, university of technology, baghdad, 2005. 15. w. kueathawikun1, p. thumwarin1, n. anantrasirichai1, and t. wakabayashi2, “wideband slot antenna for ieee 802.11b/g,” sice-icase international joint conference 2006 oct. 18-21, 2006 in bexco, busan, korea. 16. woon geun yang, chang il kim, jong dae oh, kyu ho lee, sung min kim, “design and implementation of 2.4ghz and 5ghz dual band antenna for access point of wireless lan,” north-east asia it symposium 2002, pp.573-576, nov. 2002. 17. thomas a. milligan, “modern antenna design”, john wiley & sons. 2ed. ed. 2005. basim khalaf jarulla, izz kadhum abboud and wail ibrahim khalil al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012352 figure 3 the calculated input return loss for the modeled patch element figure 1 the nearly square patch antenna. figure 2 the nearly square patch antenna with two pairs of orthogonal slits. feeding point y x feeding point dual band microstrip antenna with slit load design for wireless local area network application 353al-qadisiya journal for engineering sciences, vol. 5, no. 4, 347-353, year 2012 figure 5 the computed axial ratios around 802.11a/b/g frequencies figure 4 e-plane (y-z plane) and h-plane (x-z plane) radiation patterns. (a) f=2.45 ghz. (b) f=5.21 ghz. 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة 106 study the effect of corrosion on fatigue strength of alloy steel (ck45) using in crank shaft under shot peening processes dr.abdulhussain h.rafesh lecturer institute of technology –baghdad abstract in this study fulfilled, prediction of fatigue life for alloy steel (ck45) at the several cases: as received after shot peening after immersed in 36% mgcl2, 30 day shot peening for specimens after corrosion. all tests carried out under constant amplitude load, rotating bending at stress ratio (r = -1) and room temperature. the following conclusions are obtained: the fatigue strength increased 11% with shot penning process the fatigue strength decreased 18% after corrosion in corrosive medium the fatigue strength increased 14% with shot penning process after immersed in corrosive medium. 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة 107 بعد قذفھ قالب المستخدم في صناعة المحور ال (ck45) دراسة تأثیر التآكل على مقاومة التعب للفوالذ ألسبائكي لمعدنیةا تبالكرا 108 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة (shot tumblast control panel model stb-ob), 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة 109 بعد قذفھ قالب المستخدم في صناعة المحور ال (ck45) دراسة تأثیر التآكل على مقاومة التعب للفوالذ ألسبائكي لمعدنیةا تبالكرا 110 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة 111 1jaske .c ,broek "corrosion fatigue of cathodically protected welded carbon steel in cold sea water” , final report to american petroleum institute , committee on off shore safety and antipollution research , dallas , feb. 11 , 1977. 2dugdale , d. s ,corrosion fatigue of sharply notched steel specimens” , metallurgica ,pp, 27-28 , jan , 1972. 3f .abadie , l .barrlier “ceramic shot enhancement of high strength steel endurance application to springs and gears”, icspa shot peening , 2005. 4ahmed ali hussain “corrosion – fatigue under combined loading and different conditions” , p.h.d thesis , , university of technology , baghdad 1997. 5 “optimization of the shot peening process in terms of fatigue resistance” s .romero, e .rios, presented at seventh international conference on shot peening , icsp-7 warsaw, poland, 1999. 6 “effect of shot peening on the fatigue strength of spring steel after exposure to corrosion” aleksander, grzegorz, waraw, poland, 2005. 7 “shot peening as an alternative to fatigue life improvement of ck45 steel coated with an electro less ni-cu-p” t .saeid , s .yazdani , international journal of issi, vol2 , 2005. ≤≤ σσ بعد قذفھ قالب المستخدم في صناعة المحور ال (ck45) دراسة تأثیر التآكل على مقاومة التعب للفوالذ ألسبائكي لمعدنیةا تبالكرا 112 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة σ σ σ σ 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة 113 بعد قذفھ قالب المستخدم في صناعة المحور ال (ck45) دراسة تأثیر التآكل على مقاومة التعب للفوالذ ألسبائكي لمعدنیةا تبالكرا 114 2012 لسنة 114-106 ،رابعال العدد الخامس، المجلد الھندسیھ، للعلوم القادسیھ مجلة impact resistance of local rpc al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 234 strength of reactive silica sand powder concrete made of local powders lect. mithaq a. louis civil engineering department, college of engineering al-mustansiriya university, baghdad, iraq abstract the main purpose of this research is to study the strength of the rpc incorporating local powders (reactive silica sand powder) and compare it with rpc incorporating condensed silica fume. original rpcin form of superplasticized cement mixture with powder (reactive silica sand or silica fume ), steel fiber ,and fine sand (<600 mµ)was studied in comparison with modified reactive powder concrete (mrpc) where a natural aggregate (max size 8mm)was used to replace the fine sand of the cementitious binder. in the present research work compressive strength, (incorporating local reactive silica sand powder) of reactive powder concrete and modified reactive powder concrete were studied. high 28-day compressive strengths (101-115 mpa) were gained when using local powders. keyward: cement, mixture, concrete, powder مقاومة خرسانات المساحیق الفعالة المصنعة من مساحیق محلیة میثاق البیرلویس قسم الھندسة المدنیة–كلیة الھندسة-الجامعة المستنصریة ةـــــالخالص ق (االغرض الرئیسي من ھذا البحث ھو لدراسة مقاومة .أبخرةو مقارنتھا مع الخرسانة ذات المساحیق الفعالة المنتجة من ) الرمال السلكیة الفعالة ، أو–األصلیةالفعالة ،)٦٠٠ ( ).٨( اإلسمنتیةالمطورة والتي بھا یتم استبدال جزء من الرمل الناعم في الخلطة -١٠١(تمسحوق المساحیق الفعالة المطورة و المصنعة من ال .)میكاباسكال١١٥ al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 235 introduction reactive powder concrete (rpc), is a high-strength, ductile material formulated by combining portland cement, silica fume, quartz flour, fine silica sand, high-range water reducer, water, and steel or organic fibers (william dowd, 1999). considerable amount of work has been undertaken to investigate the mechanical properties of various types of concrete. however, very limited amount of work has been published to investigate the mechanical properties of rpc and modified reactive powder concrete (mrpc) containing local reactive silica powder such as reactive silica sand powder and compare it with that fabricated with silica fume. in this study two types of powder are used (silica fume and reactive silica sand powder) as a mineral admixture with modified polycarboxylic ether and fine sand for reactive powder concrete while adding course aggregate (maximum size 8 mm) to produce a modified reactive powder concrete. the original concept of rpc was first developed in early 1990’s, by researchers at bouygues laboratory in france. rpc stems from efforts to optimize the microstructure of the matrix by precise gradation of all particles in the mix to yield a matrix with optimum density and extensive use of the pozzolanic properties of highly refined silica fume and optimization of the portland cement chemistry to produce the highest strength hydrates (molyneax and luk, 2003), (lee and chisholm, 2005). elastic properties of reactive powder concrete were studied by (washe et. al., 2004). the research reported in this paper examines elastic properties of this new material (reactive powder concrete) and discusses ultrasonic methods for evaluating young’s modulus. mechanical properties of reactive powder concrete were also studied by (pierre et. al., 1999) portland cement, silica fume, ground quartz and sand react chemically during the various processing stages in forming the material. heating reactive powder concrete for two days in a vapor-saturated atmosphere at 90 oc, once setting occurred, accelerates the pozzolanic reaction of the silica fume and modifies the structure of the hydrate. heat treatment increases the strength. results indicate that the compressive strength is very high (200 mpa) and high ductility provides high flexural strength (25-35 mpa). (perry and zakariasen, 2004) found that the ductile behavior of this material is a first of concrete, with the capacity to deform and support flexural and tensile loads, even after initial cracking. the use of this material for construction is simplified by the elimination of reinforcing steel and ability of the material to be virtually self placing or dry cast. an experimental investigation on rpc made by adding portland cement, silica fume, superfine fly ash, and super plasticizers was reported by (wen-yu et. al., 2001). they showed that the rpc has high strength (157 mpa at 6 days, 147.3 mpa at 28 days), high durability, including excellent impermeability of chloride and frost-resistance, high split tensile strength (15 mpa at 6 days 21.1 mpa at 28 days), and elastic modulus of 48.5 gpa at 28 days. rpc also has ultra-high durability characteristics resulting from extremely low porosity. penetrations of liquid and/or gas become nearly non-existent in comparison to high performance concrete hpc (dauriac, 1997). (jianxin, 1996) reported that the original uhpc was modified through partial replacement of cement or silica fume by fine quartz powder and also showed that the compressive strength higher than 200 n/mm2 can be reached under normal curing condition. from the previous review, it can be noticed that there are very few studies concerning mrpc and available data were not found about the properties of rpc and mrpc incorporating iraqi reactive silica sand powder. in the present work, the compressive strengths of reactive powder concrete (rpc) and modified reactive powder concrete (mrpc) containing condensed silica fume and local reactive silica sand powder are studied. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 236 experimental work materials cement tasluga ordinary portland cement manufactured in iraq was used throughout this research. the used cement conforms to (iraqi specification no. 5/1984). fine aggregates two types of fine aggregate are used in this study. the first one is al-ekhaider sand and the second is silica sand known as glass sand. al-ekhaider natural sand was used as fine aggregate. it was tested to determine the grading and other physical and chemical properties. results indicated that the fine aggregate grading and the sulfate content were within the requirements of the (b.s. 882/1992 specification). for reactive powder concrete, very fine sand with maximum size 600µm is used. this sand is separated by sieving; its grading satisfies the fine grading in accordance with the b.s. specification no.882/1992. the sieve analysis of the original and the separated fine sand is shown in (tables 1and 2) in order to compare with natural fine sand, fine silica sand known as glass sand is used (table 3). this type of sand is by produced in alramadi glass factory. the sieve analysis of this sand is shown in (table 4). coarse aggregates crushed gravel obtained from al-nebai quarry was used. the maximum coarse aggregate size was chosen to be 10mm. table (5) show the grading of coarse aggregate which conforms to the (b.s. 882/1992 specification). high range water reducing admixture glenium 51 high range water reducing admixture used in this study is modified polycarboxylic ether, which is known commercially as glenium 51. glenium 51 is free from chlorides and complies with (astm c494 types a and f, 1988). (table 6) shows the main properties of glenium 51. water ordinary tap water was used in this research for mixing and curing for all concrete specimens. reactive powder in this study two types of reactive powders are used: silica fume and reactive silica sand powder. silica sand powders silica sand used throughout this investigation was crushed iraqi silica rock brought from al-ramadi glass factory. to avoid any differences between different batches, the whole quantity of silica sand was brought from the factory from a single batch and stored in a suitable place (nylon container) to avoid exposure to atmosphere or water. the chemical composition and physical properties of silica sand used in this research are shown in (table 7) and (table 8). the amorphous silica sand can be converted to very fine particles by grinding resulting in a highly active pozzolana. the grinding of silica sand was carried out in a grinding mill for a period of 24 hours for each 0.5 kg of the silica sand. the fineness was determined by blaine air permeability method in accordance with (astm c 204-84, 1989). al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 237 the silica sand, which is used throughout this work, conformed to the chemical and physical requirements of (astm c 618 class n pozzolan, 1989), (table 9 and 10) respectively. condensed silica fume this type of pozzolan is with sio2 content of 98.9%. preparation of local reactive powder grinding of cement and reactive powder produce the samples of high performance cement. the grinding process was done with a laboratory ball mill; grinding time was set at 24 hours for each 500 gm of the local reactive powder (silica sand powder) and finally grinding time was set at 120 minutes for each 500 gm of the reactive powder and cement. steel fibers the steel fibers used in this work have the properties described in (table 11). mixing of concrete the mixing was performed in a rotary mixer with a capacity of 0.1 m3. for the small specimens (50×50×50mm) mixing by hand was performed for reactive powder concrete and modified reactive powder concrete. the aggregate was used in a saturated surface dry condition. the reactive powder was mixed with cement before the addition to the mixer for 30 minutes to ensure uniform dispersion of this admixture by means of a ball mill to disperse the reactive powder particles throughout the cement particles. after that the dry materials (cement, reactive powder, aggregate) were well mixed for about 5 minutes to attain uniform mix. the required amount of tap water and superplasticizers previously mixed together was then added to the rotary mixer and the whole mix ingredients were mixed for a sufficient time. when fibers were used, they were introduced, dispersed uniformly. concrete mixes and strength results the mixes used in this work are presented in tables (12) to (16). conclusions depending on the results of this investigation on rpc and mrpc the following conclusions can be drawn: 1. it is possible to produce reactive powder concrete (rpc) and modified reactive powder concrete (mrpc) from silica sand powder or silica fume as a pozzolanic admixture, and glenium 51 as a high range water reducing admixture (hrwra). 2. the rpc or mrc containing local reactive powder (silica sand powder) were tried and investigated in order to be compared to the rpc or mrpc with classic powder (silica fume). the results were lower by approximately 18% in compressive strength. however looking at the use of local materials this may be considered a gain. 3. reactive powder concrete (rpc) with a compressive strength of 115 mpa , can be attained at age of 28 days and at 20 oc by adding local powder (silica sand powder) as a pozzolanic admixture, fine normal sand ,ultra fine steel fiber and glenium 51 to ordinary portland cement . 4. reactive powder concrete (rpc) with a compressive strength of 141 mpa can be attained at age of 28 days and at 20 oc by adding silica fume as a pozzolanic admixture, fine normal sand ,ultra fine steel fiber and glenium 51 to ordinary portland cement. 5. when fine normal sand is replaced by fine glass sand the compressive strength becomes 101 mpa and 129 mpa compared with rpcs described in points 3 and 4 mentioned above, respectively. 6. when gravel is introduced as 50% replacement to fine normal sand, the compressive strengths al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 238 becomes 90 mpa and 149 mpa compared with rpcs described in points 3 and 4 mentioned above, respectively. 7. when using silica sand powder and fine glass sand with silica fume the 28-day compressive strength reached 130 to 139 mpa for rpc and mrpc, respectively. references astm c494-86,”chemical admixture for concrete”, annual book of astm standards american society for testing and materials, vol.04-02, 1988, pp. 245-252. a s t m c 2 0 4 8 4 , “ s t a n d a r d t e s t m e t h o d f o r fi n e n e s s o f po r t l a n d c e me n t b y a i r pe r me a b i l i t y a p p a r a t u s ” , a n n u a l bo o k o f a s t m s t a n d a r d a m e r i c a n s o c i e t y f o r t e s t i n g a n d m a t e r i a l s , v o l . 0 4 . 0 1 , 1 9 8 9 , p p . 1 5 7 1 6 2 . a s t m c 6 1 8 “ s t a n d a r d s p e c i f i c a t i o n f o r c h e mi c a l a d mi x t u r e s f o r c o n c r e t e “ , a n n u a l bo o k o f a s t m s t a n d a r d a m e r i c a n s o c i e t y f o r t e s t i n g a n d m a t e r i a l s , v o l . 0 4 . 0 2 , 1 9 8 9 , p p . 2 9 1 2 9 3 . b. s . 8 8 2 , “ s p e c i f i c a t i o n f o r a g g r e g a t e s f r o m n a t u r a l s o u r c e s f o r c o n c r e t e ” , br i t i s h s t a n d a r d s in s t i t u t i o n , 1 9 9 2 . dauriac, c., “special concrete may give steel stiff competition", building with concrete, the seattle daily journal of commerce, may, 1997, pp1-5. dowd, w., “reactive powder concrete – ultra high performance cement based composite", organization, hdr engineering, inc., 1999, http://www.hdrinc.com, email: bdawd@hydrinc.com. ir a q i s p e c i f i c a t i o n n o . 5 / 1 9 8 4 , “ po r t l a n d c e me n t " . jianxin, m. “properties of ultra high performance concrete”, c e m e n t a n d c o n c r e t e r e s e a r c h , 3 ( 6 ) , 1 9 9 6 . lee, n. p., and chisholm, d. h., “reactive powder concrete”, study report by building research levy for concrete technology, study report sr 146, branz ltd, judge ford, new zealand, no. 146, 2005. molyneaux, t . g k . , a n d lu k , b. , “ i mp r o v i n g t h e i mp a c t r e s i s t a n c e o f c o n c r e t e pr o j e c t i n t e r i m r e p o r t " , u n i v e r s i t y o f li v e r p o o l , d e p a r t m e n t o f c i v i l e n gi n e e r i n g , j a n . 2 0 0 3 , p p . 1 5 . perry, h., zakariasen, d., “first use of ultrahigh performance concrete for an innovative train station canopy", concrete technology today, vol. 25, n0. 2, august, 2004. pierre, y., blais, marco couture, “precast, prestressed pedestrian bridge-worlds first reactive powder concrete structure “, new technology, pci journal, october 1999, pp. (60-70). washe, g., fuchs, p., graybeal, b., and hartmann, j., “ultrasonic testing of reactive powder concrete", the institute of electrical and electronics engineers, inc., 2004. http://www.hdrinc.com mailto:bdawd@hydrinc.com al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 239 wen-yu, j., an ming-zhe, yan gui-ping, and wang jun-min, ”study on reactive powder concrete used in the sidewalk system of the qinghai-tibet railway bridge”, international workshop on sustainable development and concrete technology ,pp.333-338, 2001. (table 1) grading of al-ekhaider natural sand compared with the requirements of b.s.882:1992 sieve size (mm) cumulative passing % limits of b.s. 882/1992 overall grading 4.75 100 89-100 2.36 91.4 60-100 1.18 81.7 30-100 0.60 65.3 15-100 0.30 23.0 5-70 0.15 8.15 0-15 (table 2) grading of separated natural sand compared with the requirements of b.s.882:1992 sieve size (mm) cumulative passing % limits of b.s. 882/1992 fine grading 4.75 100 100 2.36 100 80-100 1.18 100 70-100 0.60 100 55-100 0.30 65 5-70 0.15 11 0-15 (table 3) physical properties of the fine sand physical properties test result limit of iraqi specificationno 45/1984 specific gravity 2.60 sulfate content% 0.09 0.5(max) absorption% 0.71 materials finer than 75µm 0.093 % 5(max) (table 4) grading of separated silica sand compared with the requirements of b.s.882:1992 sieve size (mm) cumulative passing % limits of b.s. 882/1992 fine grading al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 240 4.75 100 100 2.36 100 80-100 1.18 100 70-100 0.60 100 55-100 0.30 52 5-70 0.15 10 0-15 (table 5) grading of coarse aggregate sieve analysis (mm) cumulative passing % limits of b.s.882/1992 specification 14 100 100 10 91 85-100 5 16 0-25 2.36 2.5 0-5 (table 6) typical properties of glenium 51 form viscous liquid colour light brown relative density 1.1 gm/cm3 at 20 oc ph 6.6 viscosity 128 cps at 20 oc transport not classified as dangerous labeling no hazard label required chloride content none (table 7) chemical properties of silica sand powder* oxide composition oxide content (%) sio2 98.45 al2o3 0.98 fe2o3 0.05 cao 0.6 mgo 0.8 so3 0.06 l.o.i. 2.14 * tests for chemical properties of silica sand powder were conducted by al-ramadi glass factory (table 8) physical properties of silica sand powder physical properties cement silica sand powder al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 241 setting time hr:min initial setting time final setting time 1:31 3:31 1:20 3:10 surface area (blaine method) m2/kg 240 280 specific gravity 2.58 (table 9) chemical requirement of silica sand and pozzolan astm c618 oxide composition pozzolan class n silica sand sio2+al2o3+fe2o3 min. percent 70 98.48 so3, max. percent 4 0.06 loss in ignition % max. 10 (table 10) physical requirements of silica sand and pozzolan astm c618 physical properties pozzolan class n silica sand flow table, max percent 115 110 surface area (blaine method) m2/kg 280 specific gravity 2.58 strength activity index with portland cement at 28 days, min. percent of control 75 150.5 (table 11) properties of the steel fibers description straight length 13 mm diameter 0.18 mm density 7800 kg/m3 tensile strength 1800 mpa aspect ratio 72 (table 12) mix proportion of original rpc mixtures with reactive silica sand powder mix no. 01 portland cement c (kg/m3) 940 silica sand powder ssp(kg/m3) 190 normal fine sand (kg/m3) 980 sp* % by weight of cement 8% steel fiber sf % by volume 2% water (kg/m3) 240 w/c (%) 0.25 w/(c+cm)* (%) 0.21 compressive strength at 28 days(mpa) 114.9 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 242 (table 13) mix proportion of original rpc mixtures with condensed silica fume powder (table 14) composition of reactive powder concrete with glass sand powder type silica sand powder silica fume powder mix no. 03 04 portland cement c (gm) 940 940 silica sand powder ssp (gm) 180 / silica fume sf (gm) / 200 fine glass sand (gm) 1020 970 sp* % by weight of cement 8% 8% steel fiber sf % by volume 2% 2% water (kg/m3) 240 240 w/c (%) 0.25 0.23 compressive strength at 28 days (mpa) 100.8 128.5 (table 15) composition of modified reactive powder concrete with normal fine sand mix no. 05 06 portland cement (kg/m3) 960 960 silica sand powder (kg/m3) 194 / silica fume (kg/m3) / 200 normal fine sand (kg/m3) 530 530 gravel (kg/m3) 430 426 sp* (glenium51) 8% 8% steel fiber 2% 2% water (kg/m3) 218 210 w/c (%) 0.227 0.218 mix no. 02 portland cement c (kg/m3) 940 silica fume sf(kg/m3) 210 normal fine sand (kg/m3) 990 sp* %by weight of cement 8% steel fiber sf % by volume 2% water (kg/m3) 216 w/c (%) 0.23 w/(c + cm)* (%) 0.188 compressive strength at 28 days(mpa) 141.0 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 243 flow table (%) 73 77 compressive strength (mpa) 89.6 149.1 (table 16) composition of modified reactive powder concrete with two types of powder and two types of sand mix no. 07 08 portland cement (kg/m3) 960 960 silica sand powder (kg/m3) 40 50 silica fume sf (kg/m3) 170 190 fine glass sand (kg/m3) 30 30 normal fine sand (kg/m3) 1000 550 gravel g (kg/m3) / 230 sp* (%) by weight 8% 8% steel fiber sf (%) by volume 2% 2% water (kg/m3) 224 236 w/c (%) 0.23 0.245 compressive strength at 28 days (mpa) 130.5 139.4 *notes sp = super plasticizer w/(c+cm) = ratio of water to cement and cementitious materials traffic study for al-motanabi square – kut city al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 532 improvement of traffic capacity for almustainsiriyah intersection in baghdad city asst .lecturer israa f. jasim engineering affairs baghdad university alsaadi_esraa@yahoo.com abstract capacity and level of service are the control points of the analysis of intersections and must be fully considered to evaluate the overall operator of the intersection. the objectives of the present study include the analysis, evaluation and improvement of the operation for al-mustansiriyah intersection in baghdad city and to present the best proposal to enhance the performance from the capacity point of view. to achieve these objectives, the estimated distribution of the traffic data in different directions that required for the traffic and geometrical analysis were gathered manually, while hcs traffic program is used for the requirements of traffic analysis process. it has been concluded that the flyover between al-mustansiriyah university street –al-talibia street (proposal no.2) is the best proposal to improve the operation ability of al-mustainsiriya roundabout intersection. تحسين السعة المرورية لتقاطع المستنصرية في مدينة بغداد المدرس المساعد /اسراء فاضل جاسم الشؤون الهندسية جامعة بغداد وجزالم يعابية ومستوى الخدمة هما نقاط السيطرة لعمليات تحليل التقاطعات ويجب أن تؤخذ بعين أن مفهوم الطاقة االست أن هذه الدراسة تشتمل على ؛ التحليل , التقييم و تحسين القدرة التشغيلية االعتبار عند تقييم التشغيل للتقاطع. حيث الطاقة االستيعابية .المستنصرية في مدينة بغداد وعرض أفضل المقترحات لتحسين األداء من لتقاطع ولتحقيق هذه األهداف فقد تم جمع المعلومات المرورية يدويا لمختلف االتجاهات ألغراض التحليل المروري لقد تم االستنتاج بان اقتراح تنفيذ ألغراض عمليات التحليل المروري . hcsوالهندسي بينما تم استخدام برنامج لتقاطعصرية وشارع الطالبية هو أفضل البدائل لتحسين القابلية التشغيلية مجسر بمستوى واحد بين شارع المستن .المستنصرية key words: traffic capacity, level of service (los), hcs application, peak hour factor (phf), saturation flow. nomenelature phf = peak-hour factor v15 = volume during the peak 15 min of the peak hour, on veh/15min mailto:alsaadi_esraa@yahoo.com israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 532 los = level of serves phv = peak hourly volume hcs = highway capacity software hcm = highway capacity manual hv =heavy vehicle g =green time y =yellow time l =left turn th = through turn r = right turn n = number of lanes in one direction sf = service flow los under prevailing and traffic condition for n lanes in one direction (vph) cj = capacity under ideal condition for freeway element of design speed. fw = factor to adjust for the effect of restricted lane widths (and lour) lateral clearance. fhv = factor to adjust for the effect of heavy vehicle. fp = factor to adjust for the effect of driven population introduction the underlying objective of level of service analysis is to quantify a roadway’s performance with regard to specified traffic volumes (i.e., its ability to efficiently handle a specified volume of traffic). this performance can be measured in terms of travel delay (as the roadway becomes increasingly congested) as well as other factors. the comparative performance of various roadway segments (which is determined from an analysis of traffic) is important because it can be used as a basis to allocate scarce roadway construction and improvement funds │4│. capacity is simply defined as the highest traffic flow that a roadway is capable of supporting. for level of service analysis, a consistent and reasonably precise method of determining capacity must be developed within the definition. because it can readily be shown that the capacity of a roadway section is a function of factors such as roadway type (e.g., freeway, multilane highway without full access control, or rural road), free-flow speed, number of lanes, and widths of lanes and shoulders │2│. this study will include traffic data collection, forecasting future traffic volumes, analysis of existing and projected traffic volumes, and suggestion of the possible geometric solutions to increase capacity and minimize the traffic delay. description of site al-mustansiriyah intersection is a signalized roundabout intersection located in educational zone in front of al-mustansiriyah university located in the north-east part of baghdad city. figure 1 shows a satellite image for al-mustansiriyah intersection and its approaches. it is a four leg intersection type and represents the crossing node of two main arterials (palestine street and safie al-deen al-hili street), but they becomes freeways depending on pervious studies. the high traffic and pedestrian volume at this intersection affect highly the traffic flow especially through traffic along the above mentioned arterials. scope of the study 1traffic data collection which include the counting of traffic volume for each traffic stream with classification of vehicle, improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 532 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 2traffic analysis using computer software for existing and future traffic conditions to get the level of service, 3suggest alternative geometric design proposals to improve the traffic performance across the intersection , and 4evaluation of the alternatives to choose the best one considering, the traffic performance parameters, safety to road users, and economic factors. data collection 1-traffic volume counting of traffic volumes classified by movements and vehicle composition were conducted manually for the four approaches in an average four week days, good weather conditions in january, 2007. the traffic volume for the counting period was recorded for each 15 minutes to calculate the peak hour factor at each approach, the peak hour and traffic volume variation peak hour volume by considering the traffic volume account that previously presented in table 1, an excel program is used to specify the peak hour. the peak hour is found to be between 7:00 and 8:00 a.m. figure 2 (a) and (b) shows the peak hour in addition to the variation of flow every 15 min during the time period of survey. from the traffic account, the following conclusions were observed: a. the total traffic volume during the peak hour for all approaches is (4501) pc/h. this peak hour is found to be between 7:00 and 8:00 a.m, b. it was found that the approach from palestine street from beirut intersection have the highest volume of traffic while the approach of safie al-deen al-hili street from alqahera have the lowest volume during the hours of the account, and c. for peak hour volume, the distribution of traffic volume in al-mustansiriyah intersection is as shown in figure 3. this fig. shows the total volume during the peak hour for passenger . peak hour factor (phf) the peak hour factor is defined as the ratio of total hourly volume to the maximum 15min rate of flow within the hour. phf = )( hourwithinflowofratepeak volumehourly (1) phf = min v15*4 volumehourly (2) where: phf= peak-hour factor v15= volume during the peak 15 min of the peak hour, on veh/15min. 2-saturation flow rate calculation of saturation flow rate depend on the headway data collected for queue vehicles at stop line for each approach at the time of departure on green time . israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 532 saturation flow represents one of the main parameter in which has a major affect in the capacity of intersection [1 and 3]. the existing saturation flow is calculated by using hcs software. table 1 shows the calculated saturation flow at the stop line for all approaches in al-mustansiriyah intersection by using hcs software. existing geometric design to evaluate the level of service at al-mustansiriyah intersection, it is very important to specify the number of lanes for each approach. the existing geometric layout for al-mustansiriyah intersection and its approaches are shown in figure 4. data analysis analysis of existing conditions the highway capacity software (hcs-2000) is adopted to analyze traffic conditions and achieved the existing capacity, volume to capacity ratio and calculation of estimated delay for each traffic movement at each approach. after specifying the peak hour which represent the design hour volume, it is very important to estimate the level of service (los) at al-mustansiriyah intersection with existing geometric design and traffic flow. to estimate the los for existing condition, the average delay at al-mustansiriyah intersection must be calculated because the average delay represents the main parameter for los estimation. according to highway capacity manual the (los) classified into six types depending on the value of average delay as shown in table 2. by using hcs program, the average delay for existing geometric at al-mustansiriyah intersection is (57.4) sec/veh and according to the u.s highway capacity manual, al-mustansiriyah intersection will operate in los (e). table 3 and 4 show the average delay, los's and some intersection properties for all approaches connected with al-mustansiriyah intersection. the delay values and los for most approaches is near the capacity, the result shown in table 3 is the unaccepted according to all international specification in traffic engineering. table 4 show that the los at safie al-deen al-hili from al-talibia is exceeding the capacity (los e) and needed traffic or geometric improvement. analysis of forecasted traffic data hcs is used to analysis the forecasted data through calculation of capacity, delay and los for all approaches and the whole intersection. for target year in 2025 (after 20 years with 3% annual increasing rate), the expected traffic volume will be as shown in table 5 and figure 5. the average delay will be (275.4) sec/veh and the intersection will operate at los (f). table 6 and 7 show the los's level of service and some of intersection properties at target year. the results for target year are unaccepted according to the international traffic specification. table 6 shows that all the approaches will have very high delay values which will lead to blockage of intersection area during peak hours. from site observation and traffic accounts, it was found that the capacity of this intersection is less than the traffic volume at peak hour. this means that the construction of a flyover is very important at this site so it is very important to carry out a traffic study to perform the required improvement to solve the congested traffic problem at al-mustansiriyah intersection. proposed design alternatives three geometric design proposals were suggested, and analysis of expected traffic volumes is conducted for evaluation of these proposals as follows: improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 532 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 proposal no.1: this proposal includes the execution of flyover along safie al-deen al-hili street using the same roundabout in the ground level, the expected number of vehicles which will use the proposed flyover will be as follow: about 600 pc/h from expressway towards al-talibia in peak hour. about 600 pc/h from al-talibia towards expressway in peak hour. the expected traffic volume for peak hour at ground level will be as shown in figure 6 with the execution of the proposed flyover along safie al-deen al-hili street ,the same geometric for almustansiriyah intersection was used with addition of flyover along safie al-deen al-hili street to increase the capacity of the intersection in addition to use traffic signals. the expected average delay at the at-grade level will be (55.4) sec/veh, which means the intersection, will be in los (e). table 8 and 9 show the results of analysis and some of almustansiriyah intersection properties. proposal no.2: this proposal includes removing the roundabout and use crossing intersection with signalization as shown in figure 7. by using this proposal, the results show unaccepted level of service los (e) because the average delay will be (64.3) sec/veh. table 10 and 11 show the level of service and some intersection properties at al-mustansiriyah intersection. table 10 shows that all the approaches will have very high delay values which will lead to blockage of intersection area during peak hours. proposal no.3: this proposal includes the execution of flyover along safie al-deen al-hili street with signalized intersection in the ground level ,the expected number of vehicles which will use the proposed flyover will be as follow: about 500 pc/h from expressway towards al-talibia in peak hour. about 600 pc/h from al-talibia towards expressway in peak hour. the expected traffic volume for peak hour at ground level will be as shown in figure 8 with the execution of the proposed flyover along safie al-deen al-hili street ,the new geometric for almustansiriyah intersection need to enhance the number of lanes to increase the capacity of the intersection in addition to use traffic lights. the expected average delay at the at-grade level will be (28.3) sec/veh, which means the intersection, will be in los (c). table 12 and 13 show the results of analysis and some of almustansiriyah intersection properties. table 12 shows that all the approaches will have suitable delay values at base year, which will lead to work the intersection in good conditions. for target year (after 20 years with 3% annual increasing rate), the expected traffic volume will be as shown in figure 9. the average delay will be (35.2) sec/veh and the intersection will operate at los (d). table 14 and 15 show the los's level of service and some intersection properties at target year. the results for target year are accepted according to the international traffic specification. table 14 shows that all the approaches will have suitable delay values at target year, which will lead to work the intersection in good conditions. proposal no.4: this proposal includes the execution of flyover along palestine street from with signalized intersection in the ground level .for this proposal the expected traffic volume at ground level in almustansiriyah intersection will be as shown in figure 10. the expected traffic volume, which will be use the proposed flyover, will be as follow: about 400 pc/h from beirut intersection towards al-qahera in peak hour. about 400 pc/h from al-qahera towards beirut intersection in peak hour. israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 542 for this proposal, the same number of lanes must be adopted as shown in figure 10. this proposal includes traffic light at ground level. for the base year, the results of analysis show that the average delay is (62.1) sec/veh and the intersection will operate at los (e). table 16 and 17 show the level of service of almustansiriyah intersection. table 16 shows that all the approaches will have suitable delay values at base year, which will lead to work the intersection in good conditions. for target year the expected traffic volume at the at-grade level will be as shown in figure 11. on the target year, the average delay is (291.2) sec/veh and the level of service will be (f) this delay and los are unaccepted according to the international specification. table 18 and 19 presents the above-mentioned results and some of intersection properties. table 18 shows that all the approaches will have very high delay values at the target year, which will lead to blockage of intersection area during peak hours. design of flyover (number of lane) hcm specification is used to calculate the number of lanes for the proposed flyover: for proposal no. 3 on the target year flyover along safie al-deen al-hili street (from al-talibia towards expressway) n= [sf / ( cj  c v  fw  fhv fp ) ] (3) where n = number of lanes in one direction sf = service flow los under prevailing and traffic condition for n lanes in one direction (vph) cj = capacity under ideal condition for freeway element of design speed. fw = factor to adjust for the effect of restricted lane widths (and lour) lateral clearance. fhv = factor to adjust for the effect of heavy vehicle. fp = factor to adjust for the effect of driven population. sf = 1080 pc/h (hcs software) assume los (d) c v = 0.80, fhv = 1.0, fp = 1.0, fw= 0.93 where fw = 0.93 (use standard lane with 1 ft obstruction on both sides)  n = [1080 / (1900 0.80 0.93 1.0 1.0)] = 0.76 lanes  use two lanes for each direction is too enough. conclusions by considering the previous mentioned results, and throughout the presented four proposals, it is concluded that proposal no. (3) reflects the best solution on the target year from the capacity and the performance operation point of view at al-mustansiriyah intersection in baghdad city. this proposal include construct flyover along safie al-deen al-hili street using four leg signalized intersection in the ground level with (28.3) and (35.2) sec/veh average delay in base and target year respectively, this is mean that the intersection work in los(c) and (d) for base and target year respectively. improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 542 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 referances [1]charles w. and webster f. v. ," some factors affecting the capacity of intersection controlled by traffic signals "forth int. traffic engineering conference, copenhagen., 1958. [2]khisty , c, j and lall , b. k. , "transportation engineering " , handbook , second edition , prentice –hall international ,inc. 1998. [3]transportation research board, (highway capacity manua), national research council washington, dc, special report 209, 1985. [4]zegeer, d.c., "field validation of intersection capacity factors", transportation research record 1091, transportation research board washington, dc, 1986. table 1 saturation flow at -mustansiriyah intersection saturation flow vphg movement approach 3149 th palestine street from beirut intersection 1409 r 3149 th safie al-deen al-hili from expressway 1409 r 3149 th safie al-deen al-hili street from al-talibia 1409 r 3149 th palestine street from al-qahera 1409 r table 2 level of service definitions based on delay (hcm method) level of service (los) control delay per vehicle in sec. a b c d e f d  10 10 >d  20 20 >d  35 35 >d  55 55 >d  80 80 >d table 3 existing los at al-mustansiriyah intersection approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 45.9 32.6 75.9 53.2 d c e d average intersection delay 57.4 e israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 545 table 4 properties of existing geometry for al-mustansiriyah intersection table 5 traffic volume for current and expected volume for al-mustansiriyah intersection approach movement current volume expected volume with 3 % growth factor,20 years palestine street from beirut intersection l 376 680 th 553 998 r 535 966 safie al-deen al-hili from expressway l 199 360 th 622 1123 r 480 867 safie al-deen al-hili street from altalibia l 177 320 th 670 1210 r 550 993 palestine from al-qahera l 128 230 th 686 1234 r 407 735 table 6 level of service at al-mustansiriyah intersection for the target year approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 328.0 205.6 334.8 285.8 f f f f average intersection delay 275.4 f approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection th 929 7 0.90 2 30 4 r 535 7 0.90 1 safie al-deen al-hili from expressway th 821 7 0.90 2 23 4 r 480 7 0.90 1 safie al-deen al-hili street from al-talibia th 847 7 0.90 2 26 4 r 550 7 0.90 1 palestine street from al-qahera th 814 7 0.90 2 25 4 r 407 7 0.90 1 total 120 improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 543 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 table 7 al-mustansiriyah intersection properties at target year. table 8 level of service at al-mustansiriyah intersection at target year (proposal no.1). approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 25.1 30.3 95.2 43.3 c c f d average intersection delay 55.4 e table 9 properties of al-mustansiriyah intersection after proposal no. 1 at target year. table 10 level of service at al-mustansiriyah intersection by adopting proposal (2) at base year approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 69.0 53.0 59.8 72.6 e d e e average intersection delay 64.3 e approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection th 1678 7 0.90 2 30 4 r 966 7 0.90 1 safie al-deen al-hili from expressway th 1483 7 0.90 2 23 4 r 867 7 0.90 1 safie al-deen al-hili street from al-talibia th 1530 7 0.90 2 26 4 r 993 7 0.90 1 palestine street from al-qahera th 1470 7 0.90 2 25 4 r 735 7 0.90 1 total 120 approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection th 929 7 0.90 2 30 4 r 535 7 0.90 1 safie al-deen al-hili from expressway th 221 7 0.90 2 23 4 r 480 7 0.90 1 safie al-deen al-hili street from al-talibia th 247 7 0.90 2 26 4 r 550 7 0.90 1 palestine street from al-qahera th 814 7 0.90 2 25 4 r 407 7 0.90 1 total 120 israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 544 table 11 al-mustansiriyah intersection properties after proposal no.2 at base year table 12 level of service at al-mustansiriyah intersection by adopting proposal no. (3) on the base year. approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 27.0 35.6 36.8 24.3 c d d c average intersection delay 28.3 c table 13 al-mustansiriyah intersection properties after proposal no. 3 at base year table 14 level of service at al-mustansiriyah intersection for the target year (proposal no.3) approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 33.3 38.7 48.8 31.3 c d d c average intersection delay 35.2 d approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection l 376 7 0.90 1 34 4 th 553 7 0.90 3 safie al-deen al-hili from expressway l 199 7 0.90 1 28 4 th 622 7 0.90 3 safie al-deen al-hili street from al-talibia l 177 7 0.90 1 20 4 th 670 7 0.90 3 palestine street from al-qahera l 475 7 0.90 1 22 4 th 570 7 0.90 3 total 120 approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection l 376 7 0.90 2 30 4 th 553 7 0.90 3 palestine street from al-qahera l 475 7 0.90 2 34 4 th 570 7 0.90 3 safie al-deen al-hili from expressway l 199 7 0.90 3 20 4 th 122 7 0.90 1 safie al-deen al-hili street from al-talibia l 177 7 0.90 3 th 170 7 0.90 1 total 96 improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 542 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 table 15 al-mustansiriyah intersection properties after proposal no. 3 at target year table 16 level of service at al-mustansiriyah intersection on base year (proposal no.4) approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 101.2 25.2 28.5 122.4 f c c f average intersection delay 62.1 e table 17 properties of al-mustansiriyah intersection after proposal no. 4 at base year. table 18 level of service at al-mustansiriyah intersection at target year (proposal no.4) approach average delay sec/veh level of service(los) palestine street from beirut intersection safie al-deen al-hili from expressway safie al-deen al-hili street from al-talibia palestine street from al-qahera 478.6 34.5 57.8 777.2 f c e f average intersection delay 291.2 f approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection l 680 7 0.90 2 30 4 th 998 7 0.90 3 palestine street from al-qahera l 858 7 0.90 2 34 4 th 1029 7 0.90 3 safie al-deen al-hili from expressway l 360 7 0.90 3 20 4 th 219 7 0.90 1 safie al-deen al-hili street from al-talibia l 320 7 0.90 3 th 306 7 0.90 1 96 approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection l 376 7 0.90 2 24 4 th 133 7 0.90 1 palestine street from al-qahera l 475 7 0.90 2 th 170 7 0.90 1 safie al-deen al-hili from expressway l 199 7 0.90 1 26 4 th 622 7 0.90 3 safie al-deen al-hili street from al-talibia l 177 7 0.90 1 23 4 th 670 7 0.90 3 total 85 israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 542 table 19 properties of al-mustansiriyah intersection after proposal no. 4 at target year. figure 1 satellite image for al-mustansiriyah intersection in baghdad city a. car. approach movement vol. % hv phf no. of lane cycle length (sec.) g y palestine street from beirut intersection l 680 7 0.90 2 24 4 th 239 7 0.90 1 palestine street from al-qahera l 858 7 0.90 2 th 306 7 0.90 1 safie al-deen al-hili from expressway l 360 7 0.90 1 20 4 th 1123 7 0.90 3 safie al-deen al-hili street from al-talibia l 320 7 0.90 1 23 4 th 1210 7 0.90 3 total 85 شارع صفي الدين الحلي improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 542 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 figure 2 (a) distribution of traffic volume from 7:00 a.m to 4:30 p.m at al-mustansiriyah intersection. figure 2 (b) total of traffic volume every 15 min for all approaches at al-mustansiriyah intersection. israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 542 figure 3 peak hour volume, the distribution of traffic volume in al-mustansiriyah intersection. figure 4 existing geometrical design of al-mustainsiriya intersection. improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 542 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 figure 5 expected traffic volume for al-mustainsiriya intersection at target year. figure 6 expected traffic volume at base year with adopting proposal no. (1). israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 522 figure 7 proposal no.2 (crossing intersection). figure 8 expected traffic volume at base year with adopting proposal no. (3) improvement of traffic capacity for al-mustainsiriyah intersection in baghdad city 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 figure 9 expected traffic volume for al-mustansiriyah intersection at target year figure 10 traffic volume at al-mustansiriyah intersection at peak hour with proposal 4 at base year. israa f. jasim al-qadisiya journal for engineering sciences, vol. 5, no. 3, 235-252, year 2012 | 525 figure 11 traffic volume at al-mustansiriyah intersection at target year with (proposal no.4). <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 54 the effect of different cycle arrangements on the performance of open gas turbine power plant dr. mohamed f. al-dawody, dr. naseer h. hamza mohamed.aldawody@qu.edu.iq, naseer.hamza@qu.edu.iq department of mechanical engineering, university of al-qadisiyah, ad’diwaniyah, iraq received on 14 january 2017 accepted on 19 february 2017 abstract the use of gas turbine is increasing day by day for producing electricity and for various industrial applications. in this work a new approach of study for the effect of different cycle arrangements on the performance of simple gas turbine has been investigated. the new cycle arrangements include: reheat with heat exchanger, reheat with water injection, heat exchanger with water injection and reheat together with heat exchanger and water injection. all these arrangements are compared to the performance of gas turbine cycle with no modifications. a matlab code was written to calculate the combustion characteristics and major performance parameters such as net work, fuel/air ratio, specific fuel consumption, and thermal efficiency ….etc. it’s observed that using reheat in addition to heat exchanger with water injection gives higher thermal efficiency, maximum increment was 28.6% in compare with normal basic cycle and lower fuel consumption, maximum reduction was 22.2 in compare with normal basic cycle. keywords: gas turbine, open cycle, modifications, water injection, heat exchanger, reheat الخالصة یر دمج التحسینات المختلفھ على دوره التوربین الغازي بشكل جدید. شملت الدراسة استخدام في ھذا البحث تم دراسة تاث ین مع تقنیة ضخ الماء، ومره اخرى المبادل الحراري مع ضخ الماء واخیرا خاعادة التسخین مع المبادل الحراري، اعادة التس مج بلغة ماتالب الیجاد خصائص االحتراق و العوامل المؤثره المبادل الحراري واعادة التسخین مع ضخ الماء سویة. تم بناء برنا ) %٢٨.٦( على اداء المحطة ومنھا:الشغل الصافي ومعدل استھالك الوقود والكفاءة الحراریة ....الخ. لوحظت اعلى كفاءة حراریة مبادل الحراري مع تقنیة حقن %) عند استخدام نظام اعادة التسخین باالضافة الى نظام ال٢٢.٢مع اقل معدل استھالك للوقود ( الماء بالمقارنة مع الدوره االساسیة للتوربین الغازي. nomenclature symbol definition unit t temperature k cp specific heat at constant pressure kj/kg.k c1,c2 parameters of fuels h specific enthalpy kj/kg f fuel to air ratio w work kj/kg s.f.c. specific fuel consumption kg/kw.hr pr pressure ratio al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 55 lhv q lower heating value per unit mass kj/kg c.c combustion chamber greek symbols symbol definition unit g specific heat ratio h efficiency subscript symbol definition a air b burner c compressor g gas m mechanical max. maximum n net r ratio t turbine introduction in the present time a good and compact stationary gas turbine engine has been introduced with capacity of 425 mw and pressure ratio of 20 according to siemens. but the main focus still directed to the development of metallurgic limit of alloys of turbine blades which allows to reach a high temperature at the turbine inlet which in its turn permit to burn more fuel safely, which means more power output. the demand of electricity is increasing day by day especially in such developing country like iraq. the electricity demand also hits the maximum in the summer days which unfortunately implies a lower value of air density and lower mass of flowing air and consequently this lowers the produced power. also, the ambient conditions play an important role which is affecting the mass flow rate and moisture content of air in the flow passages in the gas turbine power plant and if the attention is paid to the severe climate conditions of middle east countries in general and in iraq in particular, the need of adopting a good technique for cooling the incoming air in the gas turbine power plant becomes an urgent issue. for the mentioned reasons this paper is focused to find a non-traditional way to increase both power output and thermal efficiency of the gas turbine cycle with taking into consideration the best compromised way to enhance the power output without increasing too much the amount of burning fuel to avoid any more contributions in the greenhouse effect. the adopted method is trying to apply new configurations and in the same time multiple operating conditions which grant the best result concerning the major performance parameters like power output (which is related to the electricity demand issue), specific fuel consumption (which is related to the greenhouse effect issue) and thermal efficiency (which is related to the economic justification of the gas turbine power plant). theoretical analysis in this work the mathematical analysis falls into two sections, the first section deals with the analysis of simple cycle of open gas turbine, and the second section deals with the analysis of modified cycle open gas turbine which include (intercooling, reheat, and heat exchanger). all theoretical analysis of this study is made according to the following assumptions: 1. both compression and expansion processes are isentropic. 2. no potential energy change between inlet and outlet of each component. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 56 3. the pressure drop through air inlet duct, combustion chamber, nozzles…etc., are neglected. 4. mass flow rate is constant throughout the cycle. 5. the specific heat is not strongly function of temperature variation, i.e., the specific heat is constant. the reheat cycle allow to reach the maximum temperature in gas turbine cycle again in the combustion chamber without exceeding the metallurgical limit of turbine vanes, i.e., not to exceed the maximum allowable temperature at the inlet of the turbine. the heat exchanger uses the energy of the exhaust gases at outlet from the turbine which serve multiple goals: the first is to use the wasted thermal heat in heating the incoming air from the compressor. the second is to prevent the thermal pollution which is in part coinciding with global trends in minimizing the greenhouse effect especially in such severe hot environmental condition like these in iraq. thirdly is to minimize the fuel flow rate which reflected positively on the economic justifications of overall operation of the gas turbine power plant which is in common has a poor thermal efficiency. the method of water injection in the inlet air duct of the compressor implies a cooling effect on the operation condition on different parts of the gas turbine power plant. some of the cooling effect comes as a result of evaporative cooling of water vapor during the compression process in the stages of compressor and the rest from the direct injection of very fine and atomized water droplets in the flow passages of the compressor. the cooling process majorly gives the following advantages: it minimizes the work of the compressor which in turn raises the thermal efficiency in overall. it stimulates the combustion process positively because of the role of the steam which is converted from the injected water. it gives a good possibility to increase the fuel rate which in turn increases the brake power output of the plant during the hot summer days when electricity demand hits the maximum. it decreases the nox emissions because of lowering the flame temperature in the combustion chamber. simulation of simple cycle figure (1) shows a simplified diagram of simple gas turbine which describes basic components of the plant which are explained very briefly below: 1. compressor: the task of compressor is to increase the pressure of incoming air so that the compression and power extraction processes after combustion can be carried out more efficiently. during the isentropic compression process: (1) the isentropic efficiency of compressor is given by the following empirical relation (jaber et al., 2007 ) ( ) ú û ù ê ë é ÷ ø ö ç è æ -+ -= 300 109.0 1 rp c h (2) ( ) a aa a pr p p t t g gg g 1 1 1 2 1 2 =÷÷ ø ö çç è æ = al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 57 also, it is defined as the ratio of work input required in isentropic compression between p1& p2 to the actual work required, (willard w,1997). 1 / 2 12 tt tt c =h (3) so the work input to the compressor is: ( ) mac ttcpw h/* 1 / 2 -= ; where m h mechanical efficiency (4) 2. combustion chamber: the combustion chamber is designed to burn a mixture of fuel and air to deliver the burned gases to the turbine at a uniform temperature. the gas temperature of the turbine must not exceed the allowable structure temperature of the turbine (jack, d.1998). since the process is assumed to be adiabatic with no work transfer and neglected pressure loss, so the energy equation, is simply ; ( ) ( )å =-0. ,/23, tfii hfhhm (5) now making the enthalpy of reaction at a reference temperature of 25 °c, so equation can be expanded in the usual way to get; ( ) ( ) ( ) ( ) 0298.298..298..1 / 2max =-+-++-+ fftalhvtgt tcpftcpqftcpf (6) by simplifying equation (6) the theoretical fuel to air ratio will be: ( ) ( ) ( )( ) lhvg ag t qttcp ttcpttcp f +-+= 1max 1 / 2max1 . .. (7) the actual (fuel / air) ratio for given temperature difference is given by; (8) 3. turbine: the purpose of turbine is to extract kinetic energy from the expanding gases which flow from the combustion chamber (jack, d.1998). the kinetic energy is converted to shaft horse power to drive the compressor and other components. nearly three-forth of all energy available from the product of combustion is required to drive the compressor. during the isentropic expansion process: (9) the isentropic efficiency of turbine is given by the following empirical equation (jaber et al., 2007 ) (10) bta ff h/= ( ) g gg g pr p p t t g gg g 1 1 3 4 max 4 =÷÷ ø ö çç è æ = ú ú ú ú û ù ê ê ê ê ë é ÷ ÷ ÷ ÷ ø ö ç ç ç ç è æ -= 250 1 9.0 1 2 t t t h al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 58 similarly the isentropic efficiency of compressor is defined as the ratio of actual work output to the isentropic work output between p3 and p4 (11) then the turbine work output is: (12) the net work output is determined by subtracting equation (12) from equation (4). the work ratio is defined as the ratio of net work output to turbine output work:. t n r w w w = (13) the specific fuel consumption is given by; (14) then the cycle thermal efficiency is found there from the equation below (jack, d.1998); lhv th qcfs *... 3600 =h (15) simulation of modified cycle instead of using conventional modifications (intercooling, reheating and heat exchanger) which is added separately to the basic cycle by different works papers. a new approach of modifications are presented in this paper by adding two or three techniques together and compared to the basic cycle of gas turbine.the new arrangements are summarized below: 1. reheat with heat exchanger 2. water injection and heat exchanger 3. water injection with reheat 4. reheat with heat exchanger and water injection the objective of using such kind of arrangements is to boost the efficiency and performance levels of the plant as compared to the original basic cycle of gas turbine. 1. reheat with heat exchanger the method of improvement specific power output is achieved in reheat cycle at the expense of the efficiency. this can be overcome by adding a heat exchanger to the reheat cycle. the schematic arrangement of the reheat cycle with heat exchanger is given in fig. (2). the higher exhaust temperature is now fully utilized in the heat exchanger. in fact when a heat exchanger is employed, the efficiency is higher with reheat than without. the high pressure turbine must be exactly equal to the work input for the compressor with the following equation (15) 4 / 4 tt tt xma xma t =h ( )/ 4 * ttcpw xmagt -= n a w f cfs 3600 ... ´ = ( ) ( )/ 5max 1 / 2 .. ttcp tt cp g m a -= h al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 59 for the first combustion chamber, the energy equation is used (16) the first theoretical fuel/air ratio is calculated from expanding equation (16) as follows; (17) (18) the same procedure is used for second combustion chamber; ( ) ( )å =-0. 2/44, ftii hfhhm (19) the second fuel/air ratio is then calculated as follows; ( ) ( ) ( ) ( ) 0298.298..298..1 2 / 4252 =-+-++-+ fftglhvtgt tcpftcpqftcpf (20) (21) then the total fuel/air ratio is given by; 21, tttott fff += (22) the total actual (fuel / air) ratio for given temperature difference is given by; (23) the net work of the plant is equal to work output of low pressure turbine ( )/ 752 . ttcpww gtn -== (24) the work ratio is given by; t n r w w w = (25) the specific fuel consumption is given by; (26) finally the plant efficiency is found below ; ( ) ( )å =-0. 1/23, ftii hfhhm ( ) ( ) ( ) ( ) 0298.298..298..1 1max1max1 =-+-++-+ fftalhvtgt tcpftcpqftcpf ( ) ( ) ( )( ) lhvg ag t qttcp ttcpttcp f +-+= 1max 13max1 1 . .. ( ) ( )( ) lhvg g t qttcp ttcp f += 1max max / 5 2 . . btotttota ff h/ ,, = n tota w f cfs 3600 ... , ´ = al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 60 lhv th qcfs *... 3600 =h (27) 2. water injection and heat exchanger gas turbines are very sensible to ambient air wet bulb temperature. for instance, if the gas turbine operates with an ambient temperature of 35 °c a reduction about 20% of its capacity of generation may occur when compared to iso standard conditions of 15°c. this is due to the direct influence of air density on the amount of air introduced in the combustion chamber (at higher temperatures, air presents low density and, therefore the air mass supplied to the turbine is reduced). previous studies (guimarães 2000, bassily 2001) have demonstrated the advantages of the use of evaporative panels in the cooling of the air of the gas turbines. during the gas turbine cycle the ambient air is initially cooled and humid in the direct evaporative cooler (dec) due to simultaneous mass and heat exchange between the air stream and the wet surface of the panel. the mathematical model implemented for the system under study involves the following main considerations: (i) panel is well insulated. (ii) neglecting the change in the kinetic and potential energy. (iii) the pressure drop through the inlet air duct of the compressor where the direct evaporative cooling occurs is neglected. (iv) the change in the absolute humidity of the air is ignored. the schematic diagram of the direct evaporative panel that is adopted in this work is shown below: figure (1) shows the schematic diagram of dec on the other hand the exhaust gases leaving the turbine at the end of expansion are still at a high temperature (high enthalpy). if these gases are allowed to pass into atmosphere, this represent a loss of available energy, this energy can be recovered by passing the gases from the turbine through a heat exchanger, where the heat transfer from the gases is used to heat the air leaving the compressor. therefore the function of heat exchanger is to heat the outlet air from compressor (t / 2 to t3) and to cooled the exhausted gases from turbine (t / 5-t6) as shown in figure.(3) and figure (4), so the ideal heat exchanger have (t / 2=t6) and (t3=t / 5) which is assumed in this work. the theoretical analysis of this arrangement will be summarized in the following couples of equations during the isentropic compression process: (28) ( ) a aa a pr p p t t inj new g gg g 1 1 1 2 1 2 =÷÷ ø ö çç è æ = al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 61 the isentropic efficiency of compressor is given by the following empirical relation ( ) ú û ù ê ë é ÷ ø ö ç è æ -+ -= 300 109.0 1 rp c h (29) it is defined as the ratio of work input required in isentropic compression between p1& p2 to the actual work required, (willard w,1997). injnew injnew c tt tt 1 / 2 12 =h (30) so the work input to the compressor is: ( ) minjnewac ttcpw h/* 1 / 2 -= ; where m h mechanical efficiency (31) the combustion process will be the same as its in the simple cycle except the temperature entering the combustion chamber will be treated in the heat exchanger unit hence, the theoretical fuel to air ratio is given by: ( ) ( ) ( )( ) lhvinjg injainjg t qttcp ttcpttcp f +-+= 1max 13max1 . .. (32) the actual (fuel / air) ratio for given temperature difference is given by; (33) during the isentropic expansion process (34) the isentropic efficiency of turbine is given by the following empirical equation (35) similarly the isentropic efficiency of compressor is defined as the ratio of actual work output to the isentropic work output between p3 and p4 (36) then the turbine work output is: bta ff h/= ( ) g gg g pr p p t t g gg g 1 1 3 4 max 5 =÷÷ ø ö çç è æ = 5 / 5 tt tt xma xma t =h ú ú ú ú ú û ù ê ê ê ê ê ë é ÷÷ ÷ ÷ ÷ ø ö çç ç ç ç è æ -= 250 1 9.0 1 2 inj new t t t h al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 62 (37) 3. water injection with reheat the theoretical equations of such kind of modification will be exactly the same equations used in the reheat cycle except the cooling of air temperature which enters the compressor by using water injection technology. therefore it’s enough to observe and discuss the results without need to rewrite the governing equations of performance parameters again. 4. reheat with heat exchanger and water injection the last new arrangement used in this work is to add the water injection unit together with heat exchanger and reheat systems. the analysis of such type of arrangement can be summarized as shown below; the first turbine work equal to the work input for the compressor (38) the first and second theoretical fuel/air ratios are calculated from expanding equation (16 and 19) as follows; (39) (40) then the total fuel/air ratio is given by; 21, tttott fff += (41) the network in addition to thermal efficiency and specific fuel consumption are calculated according to the procedure mentioned in the first arrangement. results and discussion the layout of the results is divided into two sections; these explain the effect of maximum temperature and pressure ratio on the performance of simple and modified cycle of open gas turbine plant respectively. in this work we studied different types of arrangements and the main target is increasing power output as much as possible without affecting negatively the value of thermal efficiency or at least not lowering it. the study start with combining the reheat and heat exchanger systems together, keeping in mind the simple cycle as an embark line for purposes of comparison. the layout of two systems components are shown in figure (3). this type of modification tends to increase the specific fuel consumption compared with the others because of more fuel is expected to burn due to presence of two combustion chambers in such cycle , i.e, consumes more fuel. as shown in figure (7) this increment by (0.1585977) kg/kw hr at pressure ratio of 4 and (0.1656321) kg/kw hr at pressure ratio of 9. figure (8) shows the specific fuel consumption versus the maximum temperature in the ( )/ 5 * ttcpw xmagt -= ( ) ( )/ 5max 1 / 2 .. ttcp tt cp g m injnes a -= h ( ) ( ) ( )( ) lhvinjg injainjg t qttcp ttcpttcp f +-+= 1max 13max1 1 . .. ( ) ( )( ) lhvinjg g t qttcp ttcp f += 1max max / 5 2 . . al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 63 cycle which is usually at combustion chamber exit. the arrange of heat exchanger is consuming fuel more than that of all modifications together, in exact this noticed to be (0.2124907) kg/kw hr at 1100 k of maximum temperature and (0.1585977) kg/kw hr at 1600 k of maximum temperature. in both cases the massage says that simple cycle still indicates weak outcomes due to absence of any improvements. the second modification is adding a water injection system in front of compressor to enhance the mass flow rate of incoming air by increasing the air density by adding more moisture to it. the numerical values of multiple performance parameters are tabulated in table 2. the specific fuel consumption and net work are increasing with increasing pressure ratio. this may be explained because of adding more mass to the plant accompanying with the injected water and the cooling effect which permit burn more fuel without exceeding the maximum allowable temperature of turbine blades. on the other hand the thermal efficiency and work ratio are decreasing slightly with increasing pressure ratio. this mainly because of the increasing in heat input to the cycle and the little increment in compressor work due to the increasing in mass flow rate. the other modification is combining the reheat and water injection. the main results are listed in tables 4 and 5. this type of combination record a lower value of thermal efficiency for the same reference maximum temperature in the cycle (1600 k) compared to the previous modification i.e., heat exchanger and water injection. this mainly belongs to effective utilization of heat of exhausted gases in the heat exchanger cycle. the net work in case of reheat and water injection is higher than that of heat exchanger and water injection because of increasing in the mass added and also due to improvement in combustion characteristics by means of moisture content of pressurized air entering the combustion chamber. finally, the study performed all modification together which they are reheat with heat exchanger and water injection. the main parameters performance are plotted in two cases with reference to maximum temperature in the cycle holding pressure ratio constant at pr=4 and the other performance curves are plotted versus pressure ratios holding tmax constant at 1600 k. it is evident that there a good reduction of specific fuel consumption compared to simple normal cycle. the reduction was about 55% depending on operating conditions as shown in figures (7 & 8). the thermal efficiency also improved in comparison to the simple cycle by about 48% in average. figures (9 & 10) display the thermal efficiency versus pressure ratio and maximum temperature in the cycle consequently. the maximum value was 48% resulted from incorporating all types of modifications in this study. the work ratio was sensitive to the change either in pressure ratio or in the maximum temperature as shown in figures (11 & 12). the work ratio tends to decrease rapidly with the increase in pressure ratio and tends to decrease in the increasing of maximum temperature. the maximum value obtained in this study was about 60%. conclusion the following conclusions can be drawn from the present work; · the use of all modifications guarantees the minimum value of specific fuel consumption. · the high thermal efficiency is obtained from the three modifications (near 48%). · promising convergence between the modification of reheat and heat exchanger and the modification of adding three systems at the same time are observed from the results, so the best compromise must be chosen between the two approaches to choose the best one. references 1. mehaboob basha, s. m. shaahid and luai al-hadhrami “impact of fuels on performance and efficiency of gas turbine power plants”, 2 nd international conference on advances in energy engineering december 27-28, 2011, bangkok, thailand. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 64 2. shyam agarwal, s.s. kachhwaha, r.s. mishra “performance improvement of a regenerative gas turbine cycle through integrated inlet air evaporative cooling and steam injection” international journal of emerging technology and advanced engineering, volume 2, issue 12, december 2012. 3. chiesa, p., lozza g., mazzocchi, l."using hydrogen as gas turbine fuel", journal of eng. for gas turbine and power, jan.,vol. 127, 2005 4. foster r.w. “a small air turbine power plant fired with coal in an atmospheric fluid bed” journal of eng. science for gas turbine and power, jan. 1990. 5. gulder o.l. “combustion gas properties and prediction of partial pressures of co2 & h2o in combustion gases of aviation and diesel fuels”, journal of eng. science for gas turbine and power, july, 1986. 6. badran o. “ study in gas turbine performance improvements” ,journal of eng. sciences vol.4, no.2, 1997. 7. jack, d. mattingly, "element of gas turbine", 1998. 8. kreutz, t. g. et al., (production of hydrogen and electricity from coal with co2 capture," proc. of the sixth international conference on " green gas control technologies", kyoto, japan, 2002. 9. lefebve a.h. “fuel effect on gas turbine combustion ignition stability and combustion efficiency”, journal of mechanical eng., 1985. 10. leung e.y.w. “universal correlation for the thermal efficiency of open gas turbine by using different fuels”, journal of eng. science for gas turbine and power, vol.107, july, 1985. 11. lozza g., chiesa, p., " co2 sequestration techniques for igcc and natural gas power plants:" a comparative estimation of their thermodynamic and economic performance", proc. of the international conference on clean coal technologies (cct 2002), chia laguna, italy, 2002. 12. schefer, r., "reduced turbine emissions using hydrogen-enriched fuels" progress report by dep.of energy, june, 2002, web site :< www.doe.com.>. 13. willard w. “engineering fundamentals of i.c.e”. , 1997. 14. saba y.a. “modeling and prediction the performance of al-hilla gas turbine power plant, m.sc. thesis, university of babylon, 2000. 15. jaber et al. “assement of power augmentation from gas turbine power plants using different inlet air cooling systems”jjmie, vol1, no.1, 2007. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 65 table (1) operating conditions of the plant compressor inlet temperature (t1) (310-300) k o specific heat ratio of air ( a g ) 1.4 specific heat ratio of exhaust gas ( g g ) 1.3333 pressure ratio (pr) (4-9) mechanical efficiency 98 % efficiency of burner 98 % fuel temperature (tf) 298 k table (2) heat exchanger and water injection (tmax=1600 k) pr sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 4 0.1585977 0.4585645 286.574 0.6126595 5 0.1585015 0.4588428 312.7946 0.5912544 6 0.1596643 0.4555011 330.6349 0.5733903 7 0.1613413 0.4507666 343.3682 0.5581262 8 0.1632282 0.4455559 352.7812 0.5448701 9 0.1656321 0.4390889 358.8822 0.531661 table (3) heat exchanger and water injection (pr=4) tmax (k) sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 1100 0.2124907 0.342261 140.4008 0.4365955 1200 0.1941074 0.374675 169.6354 0.4835959 1300 0.1812029 0.413583 198.8701 0.5232731 1400 0.1716709 0.423643 228.1047 0.5573250 1500 0.1643626 0.442480 257.3393 0.5868366 1600 0.1585977 0.458564 286.574 0.6126595 table (4) reheat and water injection (tmax=1600 k) pr sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 4 0.3507607 0.2073416 324.8009 0.4641625 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 66 5 0.3142443 0.2314355 363.0045 0.6282129 6 0.2917124 0.2493116 391.5128 0.6149067 7 0.2763488 0.263172 413.7542 0.6034904 8 0.2651755 0.2742609 413.6671 0.5935003 9 0.2566752 0.2833436 446.4438 0.5846291 table (5) reheat and water injection (pr=4) tmax (k) sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 1100 0.4071908 0.1786073 169.908 0.4863837 1200 0.3872033 0.1878271 201.5703 0.5290678 1300 0.3735173 0.1947092 232.799 0.5647444 1400 0.3636795 0.1999763 263.701 0.5950978 1500 0.3563557 0.2040862 294.3506 0.621292 1600 0.3507607 0.2073416 324.8009 0.6441625 compressor turbine figure 2 shows the basic components of simple cycle of gas turbine c.c al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 67 compressor h.p. turbine l.p. turbine figure 3 shows the modified cycle of gas turbine with reheat and heat exchanger compressor turbine figure 4 shows the modified gas turbine cycle with heat exchanger and water injection c.c.i i c.c ii h e a t e x c h a n g e r c.c h e a t e x c h a n g e r al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 68 compressor h.p. turbine l.p. turbine figure 5 shows the modified cycle of gas turbine with adding two systems: reheat and water injection compressor h.p. turbine l.p. turbine figure 6 shows the gas turbine cycle considering all systems of adopted modifications: reheat, heat exchanger and water injection c.c.i i c.c ii ii h e a t e x c h a n g e r c.c.i i c.c. ii ii al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 69 figure 7 shows the specific fuel consumption (sfc) versus the pressure ratio for different types of adopted arrangements figure 8 shows the specific fuel consumption (sfc) versus the maximum temperature in the cycle for different types of modifications 4 5 6 7 8 9 pressure ratio 0.10 0.20 0.30 0.40 0.50 0.60 s f c ( k g /k w .h r) tmax =1600 k simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) 1100 1200 1300 1400 1500 1600 tmax (k) 0.10 0.20 0.30 0.40 0.50 0.60 s f c ( k g /k w .h r) pressure ratio 4 simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 70 figure 9 shows the thermal efficiency versus the pressure ratio for different types of adopted arrangements figure 10 shows the thermal efficiency versus the maximum cycle temperature for different types of adopted arrangements 4 5 6 7 8 9 pressure ratio 0.20 0.30 0.40 0.50 0.60 t h e rm a l e ff ic ie n c y ( % ) tmax=1600 k simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) 1100 1200 1300 1400 1500 1600 tmax (k) 0.10 0.20 0.30 0.40 0.50 0.60 t h e rm a l e ff ic ie n c y ( % ) preesure ratio 4 simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 71 figure 11 shows the work ratio versus the pressure ratio for different types of adopted arrangements figure 12 shows the work ratio versus the maximum temperature in the cycle for different types of modifications 4 5 6 7 8 9 pressure ratio 0.50 0.53 0.55 0.58 0.60 0.63 0.65 0.68 0.70 w o rk r a ti o tmax =1600 k simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) 1100 1200 1300 1400 1500 1600 tmax (k) 0.40 0.50 0.60 0.70 0.80 w o rk r a ti o ( % ) pressure ratio = 4 simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 502 three dimensional finite element simulation of cold flat rolling dr. abdul kareem flaih hassan hassanein ibraheem khalaf mechanical engineering department college of engineering university of basrah basrah / iraq abstract in this paper the finite element analysis of the cold flat rolling is well presented to predict the roll force, slab velocity at entry and exit, temperature rise in the slab during cold rolling, strain and stress distribution around the slab. the effects of friction coefficient and yield stress of slab material on rolling are assumed. it is found that maximum force occurs at the position of neutral point between entry and exit, also it is found that the velocity of slab at exit is larger than that at entry. the finite element results of temperature distribution around the slab predict that there is a considerable rise in slab temperature. keywords: flat rolling, finite element analysis, slab, cold rolling, temperature تمثيل ثالثي اإلبعاد لعملية الدرفلة على البارد باستخدام طريقة العناصر المحددة أستاذ مساعد دكتور عبد الكريم فليح حسن مدرس مساعد حسنين ابراهيم خلف قسم الهندسة الميكانيكية جامعة البصرة كلية الهندسة الملخص ليل عملية الدرفلة على البارد باستخدام طريقة العناصر المحددة وذلـك لغـرض تخمـين القـوة في هذا البحث تم تح المؤثرة على الدرفيل، سرعة الكتلة المدرفلة في بداية الدخول والخروج من الدرافيل، االرتفاع في درجة حرارة الكتلة نتيجـة بنظر االعتبار معامل االحتكـاك واجهـاد األخذتم . عملية الدرفلة الدن، واخيراً توزيع االنفعال واالجهاد المؤثرة خالل التشوه قيمة للقوة المؤثرة على الدرافيل تكون في نقطة التعادل والتـي أقصىالنتائج المستحصلة توضح ان . الخضوع للمادة المدرفلة لكتلة المدرفلة تكون اكبر فـي تقع في مكان ما على سطح التماس بين منطقة الدخول والخروج كذلك توضح النتائج ان سرعة ا al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 503 ان النتائج المستحصلة بطريقة العناصر المحددة توضح ان هناك ارتفاع في . منطقة الخروج عن تلك السرعة في منطقة الدخول .درجة حرارة الكتلة المدرفلة يجب ان تؤخذ بنظر االعتبار introduction modeling of flat rolling is of great interest to industry due to the large tonnage of such materials consumed and the required quality each year. modern set-up and control algorithms for rolling mills rely on robust and accurate mathematical models of the roll bite which can predict key parameters such as rolling force, torque and forward slip as a function of the rolling parameters [jiang, tieu & lu, 2004]. the finite element technique has been used as a powerful tool in the modeling of metal forming and found a wide application in this area, in particular, in the flat rolling of steel and aluminum industries. the flat rolling process includes a large deformation, and in general, the elastic deformation is too small to be considered. the plastic deformation, therefore, is the main part that forms the desired shape and products. a rigid-plastic/visco-plastic finite element method has been employed to solve many metal rolling processes, such as flat rolling [kobayashi, oh & altan, 1989], shape rolling [(mori & osakada, 1982), (liu, 1994), (xiong, liu & wang, 2000)], edge-rolling [(xiong, liu & wang, 2000),( huisman, huetink, 1985)], special shape steel rolling [( huisman, huetink, 1985)] and so on. there are also some issues about the algorithms used to improve the simulation processes [(jiang, xiong, liu, wang, 1998), (jiang, xiong, liu, liu, wang, 2000)]. moreover, the friction variation [(jiang, hu, thomson, lam, 2000), (zhao, wang, 1987), (lenard, 1992)] at the strip–roll interface in the deformation zone has an important influence on the simulation results. in flat rolling of slabs, the deformation is inhomogeneous and has a marked effect on the contact stress distribution, the force required to deform the material and residual stresses in the final product, all of which evolve in a way that departs markedly from that under homogenous deformation conditions. their variation has a crucial effect on the service characteristics and integrity of the finished product [(vallellano, cabanillas, garc´ıa-lomas, 2008)]. therory of flat rolling in rolling processes, the workpiece is rolled between two rolls [fig.(1)], so that the plate is compressed in its thickness direction. as a consequence of this, the plate thickness is reduced. because of the constancy of volume, the plate must, however, expand in the other directions: in the length direction and also to some extent in the width direction. rolling can be divided into two types, depending on whether a flat product is rolled, or a product of more complex cross sectional shape is worked. when flat products are rolled, the process is commonly termed flat rolling. in fig.(2), a slab in rolling process is shown where the initial cross-sectional area a0 is reduced to a1. concurrently, also the initial cross-sectional dimensions of the slab – the thickness h0 and width b0 – are changed to h1 and b1 after rolling. for this case the length strain can be computed by the following equation [ henry s. valberg, 2010]: 1 0 0 1 0 1 lnlnln a a a v a v l l x ===ε (1) another measure of the total deformation is the degree of reduction, specified as the relative area reduction quantified by the expression al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 504 %100*(%) 0 10 a aa r − = (2) transformation from length strain to area reduction, or vice versa, is done by use of the equation: xer ε−−= 1 (3) roll force calculation it is of great importance in industry to be able to predict the required roll force in a rolling operation with acceptable accuracy. in the technical literature, a large number of roll force equations have therefore been proposed. the rolling load in flat rolling, under plane strain conditions, can be expressed by the following formula [ henry s. valberg, 2010], see fig. (3). lb hh ml f       + += )(2 1 3 2 10 σ (4) workpiece velocities at entry and exit zone according to xincai tan et.al model [(xincai, xiu, neal, srinivasan, jian, 2008)], (for details of this model see appendix a) the material velocity in the x direction is then given by z vh z vh v ox 22 110 == (5) implementation the finite element package deform-3d version 6.1 was used to simulate the process of cold flat rolling as follows: material data and geometry an aluminum slab of al6061 with dimensions 100x30x500 mm (wxhxl) was used as a the slab material in this simulation, see fig.(4-a), while the roll material was assumed to be rigid. the roll diameter, roll width was 300, 200mm respectively, fig.(4-b). the gap between the two rolls was 22mm, roll speed was 12 rpm and the rolling operation achieved in one pass (∆h=30-22= 8mm)under temperature of 20 ºc. a full 3d model is shown in fig.(4-c). finite element mesh the finite element mesh used in this simulation for a full model of the slab is shown in fig.(5). the type of element is brick element with total number of element of 4536 and total number of nodes of 5698 nodes. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 505 validation of the simulation model to validate the above model, it is necessary to compare the predicted results obtained by the finite element package deform-3d with other results predicted by analytical models. roll force and roll torque the roll force per unit width f can be calculated using the analytical formula of hitchcock’s [ (gudur, salunkhe, dixit, 2008)]. dx r x pf l ∫      += 0 τ (6) where p is the normal contact pressure, l is the projected contact length, x is the distance from the roll centre, r is the roll radius, and τ is the frictional shear stress at the interfaces. the roll force and torque calculated by the deform-3d fe package are shown in fig.(6). the maximum load predicted by the finite element simulation has been observed at the neutral point with a value of 2.57 mn, while the roll force estimated using hitchcock’s formula gives a prediction of 2.53 mn, see appendix a which is found in a good agreement (maximum percentage error of 2%) with the results of fe prediction. velocity at entry and exit zone table(1) shows a comparison between the result of fe simulation and the analytical result of ref.[(xincai, xiu, neal, srinivasan, jian, 2008)], see appendix a. it seems that both resuls are in good agreemnt with a maximum percentage error of 13%. fig.(7) shows the countor plot of the velocities at entry and exit for the simulated results of the finite elemnt model. results and discussion distribution of effective strain and stress figs. (8) and (9) show the contour plot of the effective strain and stress, around the work piece, respectively during the rolling process. it can be seen that the maximum value of effective strain is 0.53 and will be reached after 0.3644 sec. of process time, while a maximum value of 486 mpa effective stresses was reached after 0.2186 sec. temperature evolution during cold bar rolling the temperature rise of the workpiece during cold rolling can be attributed to various factors such as rolling speed, initial temperature of the billet, plastic deformation of the workpiece, the cross sectional shape of the workpiece at each pass, cooling condition in the individual passes. as known above the rolling process achieved at temperature 20c, fig,(10) illustrates the temperature distribution around the workpiece with maximum value 109 c. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 506 conclusions the following conclusions may be achieved from the results presented in this paper: 1. the results obtained from the present work verify that the process of cold flat rolling could be theoretically estimated using the finite element method with a reasonable degree of accuracy. 2. roll force and velocity at entry and exit for a specific rolling conditions could be predicted 3. temperature rise during the cold flat rolling for known conditions could be estimated. references c. vallellano , p.a. cabanillas, f.j. garc´ıa-lomas,"analysis of deformations and stresses in flat rolling of wire", journal of materials processing technology 1 9 5 ( 2 0 0 8 ) 63–71. h.j. huisman, j. huetink, "combined eulerian lagrangian three dimensional finite-element analysis of edge-rolling", j. mech. working technol. 21 (1985) 333–353. henry s. valberg , "apllied metal forming including fem analysis" published in the united states of america by cambridge university press, new york, 2010. j.g. lenard, "friction and forward slip in cold strip rolling", tribology. trans. 35 (3) (1992) 423– 428. k. mori, k. osakada, "simulation of three-dimensional rolling by the rigid-plastic finite element method", proceedings of the international conference numerical methods in industrial forming processes, pineridge press, swansea, 1982, pp. 747–756. p.p gudur, m.a. salunkhe, u.s. dixit,"a theoretical study on the application of asymmetrical rolling for the estimation of friction", international journal of mechanical sciences, 50 (2008) 315327. s. kobayashi, s.i. oh, t. altan, "metal forming and finite element method", oxford university press, new york, 1989, pp. 222–243. s.w. xiong, x.h. liu, g.d. wang, “analysis of non-steady state slab edging in roughing trains by a three-dimensional rigid-plastic finite element method”, int. j. mach. tools manuf. 40 (11) (2000),1573–1585 x.h. liu, "rigid-plastic fem and its application in steel rolling", metallurgy industrial press, beijing, 1994, pp. 235–275. xincai tan, xiu tan yan, neal p. juster, srinivasan raghunathan, jian wang, "dynamic friction model and its application in flat rolling", journal of materials processing technology, 207, 2008, 222-234. z. zhao, g.d. wang, "modern plastic forming mechanics", northeastern university press, shenyang, 1987, pp. 150–153. z.y. jiang, s.w. xiong, x.h. liu, g.d. wang, "3d rigid-plastic fem analysis of the rolling of a strip with local residual deformation", j. mater. process. technol. 79 (1998) 109–112. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 507 z.y. jiang, w.p. hu, p.f. thomson, y.c. lam, "solution of the equations of rigid plastic fe analysis by shifted incomplete cholesky factorisation and the conjugate gradient method in metal forming processes", j. mater. process. technol. 102 (1–3) (2000) 70–77. z.y. jiang, x.l. liu, x.h. liu, g.d. wang,"analysis of ribbed-strip rolling by rigid visco-plastic fem", int. j. mech. sci. 42 (2000) 693–703. z.y. jiang∗, a.k. tieu, c. lu,"a fem modeling of the elastic deformation zones in flat rolling", journal of materials processing technology ,146 (2004), 167–174. appendix a as shown in fig.(a1), the volume rate of material flow due to volume constancy can be written as [(xincai, xiu, neal, srinivasan, jian, 2008)] 1100 )2( vwhvzwvwh x == where w is the width of the strip, h0 and h1 are the initial thickness at the entry side and the final thickness at the exit side, respectively; z is half height in the deforming region corresponding to x coordinate; v0, vx, and v1 are the velocities in the x direction corresponding to h0, z, h1, respectively. the material velocity in the x direction is then given by z vh z vh vx 22 1100 == where 22 0 xrzz e −−= 22 0 2 )( erzzx =−+ 0z is a constant for a given rolling process, and er is the effective radius 2 1 0 h rz e += rr h h l r ee ∆+= ∆ + ∆ = 4 2 where er is the effective contact length, h∆ is the draft during rolling, and r∆ is the difference of the radii between the deformed arc and the nominal arc. an approximate value of r∆ will be estimated for each rolling process during the deformation. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 508 ( ) cfe lsl += 1 where fs is forward slip, and cl is the nominal contact length 10 hhh −=∆ ( ) hsslr ffc ∆+=∆ /2 22 4/2hhrlc ∆−∆= 1−= c e f l l s from the definition of forward slip, ( ) rrf vvvs /1 −= , so 1v can be given as a function of fs ( )fr svv += 11 where rv is the linear velocity of the roll surface. table(1): comparison between fe results and analytical results of ref.[16] present work results analytical results ref.[16] time entary velocity v0 (mm/sec) exit velocity v1 (mm/sec) entary velocity v0 (mm/sec) exit velocity v1 (mm/sec) step 10 161 183 163 185 step 20 163 184 165 188 step 30 165 186 167 190 step 40 166 187 168 191 step 60 167 188 170 193 step 70 178 189 182 192 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 509 fig.(1) flat rolling fig.(2) workpiece configurations in situations rolling commonly termed flat rolling slab fig.(3) rolling considered as equivalent to plane strain compression to deduce a rolling load formula fig.(4) geometry of slab and roll (a) slab dimensions (b) roll dimensions (c) 3d full model a c b al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 510 fig. (6) variation of roll force and roll torque during the rolling process fig.(5) the meshed slab al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 511 fig. (a1) equilibrium of forces in the deformation zone and various velocities in the roll gap during flat rolling al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 512 time = 0.0364 sec time = 0.2186 sec time = 0.3644 sec time = 0.7289 sec time = 1.0934 sec time = 1.4579 sec time = 1.8223 sec time = 2.1868 sec time = 2.5513 sec time = 2.77 sec fig. (7): counter plot of due velocities during the rolling process al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 513 time = 0.0364 sec time = 0.2186 sec time = 0.3644 sec time = 0.7289 sec time = 1.0934 sec time = 1.4579 sec time = 1.8223 sec time = 2.1868 sec time = 2.5513 sec time = 2.77 sec fig. (8): distribution of effective strain around the slab al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 514 time = 0.0364 sec time = 0.2186 sec time = 0.3644 sec time = 0.7289 sec time = 1.0934 sec time = 1.4579 sec time = 1.8223 sec time = 2.1868 sec time = 2.5513 sec time = 2.77 sec fig. (9): distribution of effective stress around the slab al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 515 time = 0.0364 sec time = 0.2186 sec time = 0.3644 sec time = 0.7289 sec time = 1.0934 sec time = 1.4579 sec time = 1.8223 sec time = 2.1868 sec time = 2.5513 sec time = 2.77 sec fig. (10): temperature distribution around the slab 1023لسنة -ولس، العدد االداسمجلة القادسيه للعلوم الهندسيه، المجلد ال 1 الخواص الميكانيكية لراتنج البولي ستايرين المقوى بألياف األرمايد محمود عبد حسان جامعة القادسية مدرس مساعد الخالصة تم في هذا البحث دراسة تأثير التقوية باأللياف على الخواص الميكانيكية لراتنج البولي ستايرين المقوى بألياف األرمايد . لقد شملت هذه الخواص كل من مقاومة الصدمة ومقاومة الشد حيث تم في البداية إستخراج الخواص لياف حيث تم تقوية الراتنج بنس وننية مختلةة من الميكانيكية لراتنج البولي ستايرين قبل وبعد التقوية باأل و دراسة تأثير ذلك على الخواص المذكورة. حصل تحسن في (15% ,30% ,45%,60%)ألياف األرمايد قيمة هذه الخواص بعد التقوية باأللياف إضافة إلى نيادة قيمة هذه الخواص مع نيادة نسبة التقوية باأللياف . إلى (37mpa)ومقاومة الشد من (160kj/m2)إلى (8kj/m2) فبالنسبة لمقاومة الصدمة إرتةعت من (328mpa) على التوالي .60% و 0لتقوية ولنس ا % الكلمات الدالة: المادة المركبة ، الخواص الميكانيكية ، راتنج البولي ستايرين ، ألياف األرمايد . mechanical properties of polystyrene resin reinforced by aramid fibers mahmoud a. hassan al-qadisiya university assist. lecturer abstract in this research the effect of the reinforcement by fibers on mechanical properties of polystyrene resin reinforced by aramid fibers was studied .the properties included impact strength , tensile strength where the mechanical properties were extracted for polystyrene resin before reinforcement by fibers, then we reinforced the resin by different weight percentage from aramid fibers (%15,%30, %45, %60)and studied the effect on the above mechanical properties. an improvement was happened in these properties after reinforcement by fibers the value of mechanical properties will increase with increasing percentage of reinforcement . impact strength increased from(8kj/m 2 ) to (160kj/m 2 ) and compressive strength from (37mpa) to (328mpa) for reinforcing percentages 0% and 70% respectively . الميكانيكية لراتنج البولي ستايرين المقوى بألياف األرمايدالخواص 2 keywords: mechanical properties, polystyrene resin, aramid fibers. المقدمة . إن عمليفة الفدمج هفذه تختلفف ففي خواصفاا الميكانيكيفة والةينيا يفةتتكون المادة المركبة من دمج مادتين أو أكثر مفففادة دديفففدة ذات خفففواص هندسفففية وفينيا يفففة تختلفففف عفففن خفففواص المفففواد الداخلفففة ففففي تففيدإ إلفففى الحصفففول علفففى يعتمد اإلستخدام العام للمادة المركبة بشكل كبير على الخواص الميكانيكية والةينيا يفة لافذه المفواد لفذلك . تركيباا لمعرفة مفدى مئ مفة فإن دراسة هذه الخواص تحت تأثير القوى واألحمال في ظروف مختلةة يكتس أهمية كبيرة يودد في الطبيعة الكثير مفن األمثلفة علفى المفواد المركبفة ومنافا أليفاف [.1هذه الخواص لمكان عمل هذه المواد ] السففليلون مففع مففادة الخشفف . أمففا فففي الصففناعة فففإن تقويففة الراتندففات باألليففاف الصففناعية هففي األكثففر إنتشففارا . و وتكففون أمففا مففواد معدنيففة متكونففة مففن المعففادن المففادة األسففا :[2]همففا لتصففنيع مففادة مركبففة يدفف تففوفر مففادتين وسففبا كاا وتتميففن بثقففل ونناففا ومتانتاففا العاليففة أو قففد تكففون مففواد سففيراميكية والتففي تمتففان بخةففة ونناففا ومقاومتاففا مواد بوليميرية المرتةعة لدردات الحرارة العالية ولكناا ضعيةة المقاومة لقوى الصدم. كذلك تكون المادة األسا نتشفففارا ل مففا تتميففن بففي مفففن خففواص ميكانيكيففة وحراريففة ديفففدة ومففن األمثلففة علففى المفففواد وهففي األكثففر إسففتعمان واا يدفف تففوفر ميففنتين مففادة التقويففة . المففادة الثانيففة هففيراتففنج البففولي سففتايرين و الةينففول والبففولي أسففتر البوليمريففة األسفا . هنفاك العالية والمطيليفة المنخةضفة حتفى تسفتطيع تقويفة المفوادأساسيتين في هكذا مواد وهي المقاومة عدة طرق للتقوية مناا التقويفة بالفدقا ق التقويفة بالتشفتت أمفا أكثفر أسفالي التقويفة شفيوعا فافي التقويفة باألليفاف شفكال مختلةفة فمنافا مفا يكفون نظرا لما تتمين بي من قوة كبيرة مقارنفة بفالمواد الراتنديفة وتكفون األليفاف بفأنوا وأ بشكل مستمر أو مَقطْع أو بشكل ظةا ر محاكة . خواص المواد المركبة تعتمفففد اإلسفففتخدامات العامفففة والاندسفففية للمفففواد المركبفففة إلفففى حفففد بعيفففد علفففى خواصفففاا الميكانيكيفففة والةينيا يفففة مثفففل للحفرارة والظفروف البي يفة مثفل الرطوبفة وأشفعة الشفم مقاومة الشد والمرونفة وقابليفة المفادة للطسفتطالة ومقاومتافا وغيرها من الخواص التطبيقية اأُلخرى . إن دميع هذه الخواص تعتمد كثيرا على التركي الدني في للفراتنج وعلفى وننففي الدني ففي وعلففى القففوى الدني يففة . كمففا تعتمففد هففذه الخففواص إلففى حففد كبيففر علففى مففواد التقويففة وعلففى المففواد [ . ومن الخواص المناقشة في هذا البحث ما يأتي :3مثل الحشوات والملدنات]المضافة . (impact strength) مقاومة الصدمة -1 ُتعبر مقاومة الصدمة عن قدرة المادة لمقاومة الكسفر تحفت تفأثير حمفل مةفادم كمفا تعتبفر مقياسفا لمتانفة المفادة تبففدإ أعلففى مقاومففة للصففدمة . ويمكففن تحسففين مقاومففة الصففدمة للراتندففات حيففث المففواد األكثففر متانففة هففي التففي بإضافة بعض المحسنات مثل مطاط بيوتادين أو إضافة الملدنات أو بترتي وتراصف السئسل البوليمريفة ولكفن [ .3أكثر الطرق فاعلية في تحسين مقاومة الصدمة هي التقوية باأللياف] 1023لسنة -ولس، العدد االداسمجلة القادسيه للعلوم الهندسيه، المجلد ال 3 . ( tensile strength)مقاومة الشد -1 تعتبر مقاومة الشفد مقياسفا لقابليفة المفادة علفى مقاومفة القفوى السفاكنة التفي تحفاول سفح المفادة وكسفرها . تتكفون المففواد المركبففة الليةيففة مففن أليففاف قويففة هشففة مةمففورة فففي المففادة األسففا التففي تتصففف بكوناففا أكثففر مطيليففة . تبففدأ خطي في البداية إستدابة للدافد المسفلط ومفع إسفتمرار التحميفل يحصفل إنحفراف المادة المركبة باإلستطالة بشكل نتيدففة لوصففول المففادة األسففا إلففى نقطففة الخضففو فففي حففين تسففتمر األليففاف باإلسففتطالة و المقاومففة حتففى تناففار [ .4مقاومتاا.وعندما تتاشم المادة األسا تةشل المادة المركبة كليا ] الجزء العملي المواد المستخدمة في البحث . -أولا . (1.05g/cm3)راتنج البولي ستايرين وكثافتي -1 . (1.47g/cm3)( ذات كثافة 0°-54)°. بشكل ظةا ر محاكة (aramid fibers)ألياف األرمايد -2 نماذج اإلختبارات . -ثانيا . (impact specimens)نماذج إختبار الصدمة -1 (astme23)صنعت حس المواصةات القياسية (charpy impact)بار الصدمة نو شاربي نماذج إخت ( . 54°وبناوية حن) (mm 0.25)ونصف قطر قاعدة الحن (mm 0.5)بعمق الحن في النماذج . (tensile specimens)نماذج إختبار مقاومة الشد -2 في تصنيع نماذج إختبار مقاومة الشد. ُأستخدم هفذا اإلختبفار (iso – r – 527)تم إعتماد المواصةة القياسية مففل شففد محففورإ بإتدففاه واحففد حيففث تففم إسففتخدام داففان اإلختبففارات لمعرفففة خففواص المففادة المركبففة تحففت تففأثير ح مففل (universal instrument)العففام . ويمكففن حسففا (kn 20)فففي قيففا هففذه الخاصففية وبمعففدل ح -التالي:ن القانون مقاومة الشد م a f  حيث : σ مقاومة الشد =(n/m2). f ل المسلط .(n)= الحم a مساحة المقطع العرضي للنموذج =(m2). الميكانيكية لراتنج البولي ستايرين المقوى بألياف األرمايدالخواص 5 النتائج والمناقشة المركبة أهمية كبيرة في مدفال إسفتخدام هكفذا مفواد حيفث يدف أن تكفون قفيم تمتلك الخواص الميكانيكية للمادة هففذه الخففواص عاليففة ومقبولففة حتففى تففيدإ عملاففا بكةففا ة . ومففن خففئل هففذه اإلختبففارات التففي ُأدريففت علففى راتففنج مثففل قففيم البفولي سففتايرين المقففوى بأليفاف األرمايففد حصففلنا علفى النتففا ج الموضففحة ففي المخططففات البيانيففة والتفي تُ مقاومة الشد ومقاومة الصدمة والصئدة ومقاومة اإلنثنا نسبة إلى نسبة التقوية باأللياف . يوضفففي قفففيم مقاومفففة الصفففدمة مفففع نسفففبة التقويفففة باألليفففاف حيفففث تعتبفففر مقاومفففة الصفففدمة بشفففكل عفففام 2الشكككك اومة الصدمة ويردع السب في ذلفك منخةضة للراتندات نظرا لاشاشتاا ولكن بعد تقويتاا باأللياف تنداد قيمة مق إلففى كففون األليففاف سففوف تتحمففل الدففن األكبففر مففن طاقففة الصففدم المسففلطة علففى المففادة المركبففة ممففا ُيحسففن هففذه [.4المقاومة . وهكذا تنداد مقاومة الصدمة مع نيادة نسبة التقوية باأللياف ] ولكففن عنففد 1الشككك تعتبففر الراتندففات مففن المففواد الاشففة حيففث مقاومتاففا للشففد منخةضففة دففدا وهففذا مففا نففراه فففي إضففافة األليففاف إلففى هففذه المففواد تتحسففن مقاومتاففا للشففد بصففورة كبيففرة حيففث إن الدففن األعظففم مففن الداففد المسففلط ليففاف تتميففن بمطيليتاففا المنخةضففة . وتففنداد تتحملففي األليففاف ممففا يرفففع مقاومففة الشففد للمففادة المركبففة وذلففك ألن األ مفل ل األلياف حين أكبر داخل الراتنج ممفا يسفمي بتونيفع الح مقاومة الشد بنيادة نسبة األلياف المضافة حيث تشة [.6المسلط علياا بشكل أفضل ] اإلستنتاجات الاشة .كوني من المواد البولي ستايرين إنخةاض قيم الخواص الميكانيكية لراتنج -1 لراتنج البولي ستايرين بعد تقويتي بألياف األرمايد وتنداد قيم الخواص تحُسن قيم هذه الخواص الميكانيكية -2 إلى (8kj/m2) الميكانيكية مع نيادة نسبة األلياف المضافة . فبالنسبة لمقاومة الصدمة إرتةعت من (160kj/m 2 % على التوالي .60% و 0 التقوية ولنس (328mpa)إلى (37mpa)ومقاومة الشد من ( المصادر [1] michel biron “ thermoplastics and thermoplastic composites ” , 1st edition , elsevier , 2007. [2] mallick ,p.k. “fiber-reinforced composites: materials, manufacturing, and design”, 3rd edition , crc press, 2007 . [3]g.morom , e.drukkler , a.weinbery , and j. banbaji “impact behavior of carbon/aramid hybrid composite ”,composites , vol.17 , no.2 , 1990 , pp.150-153. [4] mittelman and i. roman “tensile properties of real unidirectional aramid/epoxy composite”, composites, vol.21, no.1, 1990, pp.63-69. [5]ali i.al-mosawi “study of some mechanical properties for polymeric composite material reinforced by fibers”, al-qadisiya journal for engineering science, vol. 2, no 1, 2009, pp. 14 – 24. 1023لسنة -ولس، العدد االداسمجلة القادسيه للعلوم الهندسيه، المجلد ال 4 [6]abbas a. al-jeebory, ali i.al-mosawi, samara a. al-qurashi “difference fibers reinforcement percentage and its effect on mechanical properties of thermosetting resins” , alqadisiya journal for engineering science ,special issue, second conference of engineering college , al-qadisiya university ,19-20 october , 2009. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 214 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. experimental investigation for the behavior of ordinary reinforced hybrid concrete hollow core slab labeeb s. al-yassri, al-qadisiyah university, iraq. email: labeeb.husein@qu.edu.iq ammar y. ali, babylon university, iraq. mohammed m. al-khafaji babylon university, iraq. received on 28 february 2017 accepted on 11 april 2017 abstract: this paper presents an experimental study to investigate the effect of hybrid strength concrete (two types of concrete, 25 mpa and 70 mpa) on the behavior of oneway hollow core concrete slab ordinary reinforced with steel rebars. the hybrid hcss showed an enhancement in shear strength capacity, cracking load and ductility as compared with to hcs with normal strength concrete (25 mpa). the increase in shear strength capacity and cracking load were about (16%) and (29%) respectively higher than normal strength hollow core slab. also, from experimental results, the crack width of hybrid hcs was narrower than that for normal strength slab at all stages of loading. at service load stage, the width of crack was narrower than normal strength slab by about (10-31%). the failure mode still brittle diagonal shear failure. symbols: hcs: hollow core slab nsc: normal strength concrete hsc: high strength concrete hysc: hybrid strength concrete. keywords: hollow core slab, hybrid strength, shear strength capacity, cracking load, mode of failure. mailto:labeeb.husein@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 215 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 1. introduction hybrid reinforced concrete slabs", it is a term usually referrers to one of the following types of reinforced concrete slabs: composite concrete slabs resulting from using concrete of one type of strength (either normal compressive strength concrete nsc or high compressive strength concrete hsc) in addition to reinforcement of type steel, polymer or any other types of frp (artificial or natural) fukuyama, 2000 [1]. the hybrid concrete term is applied for repairing purposes stemming from casting a new layer of concrete on an old layer (using one or two different types of concrete) kawamata, 2003 [2]. in this study, the term ‘‘hybrid strength concrete (hysc) slabs’’ refers to a new principal concept of casting two different concrete types, normal strength concrete (nsc) with high strength concrete (hsc) simultaneously in the same concrete slab. normal strength concrete is cast in the tension zone (lower layer) and the hsc is cast in the compression zone (upper layer). such technique can be used to produce precast simply supported slabs subjected to positive bending moments, in order to decrease the cost of the slabs, as the role of concrete in the tension zone is mainly limited to fixing the steel reinforcement and protecting it from corrosion. casting operation of hysc slabs requires more careful techniques, and casting of the two layers must be carried out while the two types of concrete are still in their fresh condition, to insure full bond between the two layers of concrete. kheder et al, 2010 [3] investigated the ultimate load capacity and flexural cracking behavior of hysc beams and compare them with similar nsc and hsc beams, also to check the compatibility of using two types of concrete in the same beam. they were noticed that ultimate load carrying capacity of the hysc beams were considerably higher than nsc beams and only slightly lower than corresponding hsc beams. also, he found that the using of hysc beams with concrete of strength 70 mpa casted in the compression zone of the tested beam sections permitted the increase of the balanced steel ratio of the beam to be similar to that of the high strength concrete used (70 mpa). implementing the hysc beams concept resulted in an average reduction in crack widths at service and ultimate load levels in these beams by 19.5 and 26.0% compared with nsc beams and a reduction of 9.2 and 15.1% compared to hsc beams. pisanty, 1992 [4] was investigated experimentally and analytically the shear strength of extruded pphcs and study the accurate of assessment of shear strength estimated by aci-code [5] and fip recommendation [6]. ten slab specimens have been tested, all failing in the shear mode (six in shear tension mode). the analysis explores ways of employing existing procedures for predicting the shear capacity. it was concluded that modification of the fip recommendations would lead to a better approximation of the test results. the major aim of this study is to investigate the shear strength capacity, flexural cracking behavior and ductility of hysc hollow core slabs and compare them with similar normal strength concrete slab, and also to check the compatibility of using two types of concrete in the same slab, for the reason that these types of concrete (normal strength and high strength) have different properties at elastic stage and also have different cracking behavior. the investigation of formation of flexural crack behavior in concrete with increasing load is necessary for a appropriate design of concrete structures [7]. traditional steel rebar is provided to carry tensile stresses in a slab due to applied load. 2. experimental work current experimental works include a series of tests conducted on several materials of building construction, control specimens such as (cubes, prisms and cylinders), and the slab specimens. the tested slabs were fabricated from normal strength r.c. or from hybrid r.c. (i.e., placement of different types of al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 216 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. concrete (nsc and hsc) in the same section). three percentages of replacement were used here (25, 50 and 75 % by casting a layer of hsc in the compression zone of slab of thickness 25, 50 and 75 mm respectively). 2.1. specimens description the experimental program consisted of testing four reinforced concrete slab models. all tested slabs were one way slabs with same dimensions of length (1200 mm), span (1100 mm c/c of supports), total width (600mm), overall depth (100mm) and clear cover of (20 mm).all hollow core slab tested here have the same cross section details of reinforcement and voiding ratio 26%. all slabs were reinforced with 6 mm deformed rebars in tension zone with tensile steel ration equal to 0.5%. this ratio taken larger than minimum and lower than maximum ratios specified by aci 318m-11 [5]. full details of hollow core slabs are given in table 1 and figure 1. all specimens of this study was tested under two line loads as shown in figure 1. table 1 details of tested slabs figure 1 dimensions details of tested slabs sample code description no. voids ratio% concrete type flexural reinforcement thickness of hsc layer mm os.h26.hr0.hc0 26 nsc steel 0 1 os.h26.hr0.hc25 26 nsc steel 25 1 hsc os.h26.hr0.hc50 26 nsc steel 50 1 hsc os.h26.hr0.hc75 26 nsc steel 75 1 hsc al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 217 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.2. materials hybrid concrete was produced from using of both normal and high strength concrete materials. the hysc hcs shear strength capacity depends primarily on the properties of high strength concrete used in the compression zone of the slab. the production of hsc that consistently meets requirements for workability and strength development places requirements that are more stringent on the selection of materials than for normal strength concretes. super plasticizers are used to achieve a low (w/c) ratio. the following is a general explanation of the used materials 2.2.1. cement ordinary portland cement manufactured in iraq named al-douh was used throughout this investigation. properties of this cement were agree with the limits of iraqi specifications (i.q.s.5/1984) [8] of portland cement. 2.2.1. fine aggregate sand (nature fine aggregate) used in this research were from al-ukhaidher region in iraq. particles grading of this aggregate obtained from results of laboratory test were agree with the iraqi (i.q.s.45/1984) [9] and (astm c33) [10] specifications. 2.2.2. coarse aggregate maximum size of 10 mm for the coarse aggregate were selected to use in this research type crushed to ensure complete filling and consolidation around the holes. it was brought from al-nibaey region. the properties of this gravel were agree with the limits of iraqi specifications (i.q.s. 45/1984) [11]. 2.2.3. silica fume (mineral admixture) microsilica fume (sf) one of production of sika company in u.a.e under commercial name (sika® fume s 92 d). 2.2.4. superplasticizer superplasticizer based on modified polycarboxylic ether used throughout this work was "glenium 54" with nominal dosage of (2.5-0.5 liter per 100kg of cement) as recommended by the manufacturer. the material is classified as type (a) and (f) in astm-c494 (94) [11]. 2.2.5. ultra-bond (sbr) is an aqueous dispersion of styrene butadiene copolymer when mixed with cementitious products giving high performance water resistant properties. sbr always using in concrete to improves workability, strength and abrasion resistance, adhesion and bonding and allows reduction in water content. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 218 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.2.6. mixing and curing water clean tap water of al-hilla, babylon, was used for wishing the aggregates, mixing and for curing all the specimens. 2.2.7. steel bar tensile test of steel reinforcement was carried out on (ø 6mm) hot rolled, deformed, mild steel bars employed as tension reinforcement for both, flexure and shear. table 2 gives the results of tensile test for bar (6 mm). table 2 physical properties of steel rebar weight (kg/m) nominal diameter (mm) measured diameter (mm) yield stress (mpa) ultimate strength (mpa) 0.229 6 5.91 556 741 2.3. mix proportions mixture of normal and high strength concrete used in this study was designed in accordance with british standard bs 5328 [12]. nominal 28-day target compressive strength for nsc was (25mpa). it was found that the selected mixture (table 3) produced good workability and homogeneous mixing of the concrete without separation. table 3 trial mixes for nsc and hsc nsc hsc mix no. 1 1 2 3 4 (selected) 5 cement (kg/m 3 ) 310 450 460 525 535 550 silica fume (kg/m 3 ) n/a 45 40.5 42 43 40 sand (kg/m 3 ) 700 680 675 720 700 705 gravel (kg/m 3 ) 1150 1020 1000 1000 1050 1050 sp. (lt./m3) n/a 4 5 5.25 5.30 5.5 sbr (lt/m3) n/a 6 8 9 9.3 8 water (lt./m3) 139.5 142.5 135.5 170 164 163 w/c 0.45 0.3 0.27 0.3 0.28 0.29 f`c (28 day) mpa 27.11 45.28 43.47 58.11 69.54 82.9 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 219 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the employed chemical admixtures (super plasticizer), low ratio of water-cement and high content of cement make the design of the mixture of hsc a more critical process with respect to the design of nsc mixtures [12]. thus, several trial mixtures have been carried out through the earlier stages of this work. the control samples taken from these mixtures were tested at (7, 14 and28 days). from the experimental mixture experiments, it was found that the mixing proportions given in table 3 were good enough to provide sufficient strength and workability. using of super plasticizer gives enough time for mixing and permits to produce homogenous mixing of concrete and prevent segregation. the selected hsc mix gives an average compressive strength of (69.54mpa) at (28 days). 3. experimental results the experimental results of the tested slabs (nsc, and hysc slabs) were compared to study the effect of using hybrid concrete concept on the structural behavior of the hcs such as ultimate and cracking loads, ductility, width of crack and the mode of failure. 3.1. cracking and ultimate loads and failure mode table 4 summarizes the experimental results of tested hcs specimens. these results including, first cracking load of flexural and shear cracks and their percentages with respect to the ultimate load, ultimate load and mode of failure of specimens also reported. table 4 test results of the tested slabs no. slab designation r* pcr (kn) (flexura) pcr (kn) (shear) pu (kn) pcr/pu % (flexural) pcr/pu% (shear) mode of failure 1 os.h26.hr0.h c0 --21 35 78.7 26.7 44.5 diagonal flexuralshear 2 os.h26.hr0.h c25 1 23 43 74.36 30.9 57.82 diagonal flexuralshear 3 os.h26.hr0.h c50 1 26.5 44 90.3 29.3 48.72 diagonal flexuralshear 4 os.h26.hr0.h c75 1 27 44.6 91.8 29.4 48.58 diagonal flexuralshear control specimen os.h26.hr0.hc0 this control slab specimen was made from nsc for overall its section that voided by eight cores of diameter 50 mm with about 26% voiding ratio, which is regarded as reference (control) specimen for al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 220 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. comparison with other specimens. the first visible crack observed within maximum moment region of the tension face of slab (flexural cracks) at lower load of (21 kn) (i.e. 26.7% of ultimate load). the first visible diagonal shear cracks appeared at (35 kn) (i.e. 44.5 % of ultimate load) within shear span. more flexural cracks and shear flexural cracks formed later at constant moment region with increasing of applied load and the inclined cracks became wider and propagated rapidly. with increasing of load, major diagonal shear crack opened more and sudden flexural diagonal shear failure occurred at load of about (78.7 kn) as shown in plate 1. figure 2 illustrates load deflection response for this control hcs. plate 1 mode of failure and cracks pattern of specimen os.h26.hr0.hc0 figure 2 load deflection response of os.h26.hr0.hc0 specimen specimen os.h26.hr0.hc25 this slab specimen was fabricated from hysc by casting layer of hsc of 25 mm thickness in compression zone monolithically over layer of nsc of 75 mm thickness in tension zone. traditional steel bars was used to reinforce this specimen in tension zone. the first visible crack was formed at relatively high load of (23 kn) (30.9% of ultimate load) at the tension face of slab within the constant moment region. with respect to control specimen (os.h26.hr0.hc0), cracking load increased by about 9% due to the increasing in compressive strength of concrete that led to increasing uncracked moment area despite that the tension al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 221 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. zone of slab were cast with nsc. later more cracks were generated at the region of max constant moment as shown in plate 2. diagonal shear crack observed within shear span at load about (43 kn) with increasing of load, major diagonal shear crack opened more until sudden bond splitting failure between two layers of different concrete type were occur at load of (74.36 kn). figure 3 illustrates load deflection responses of (os.h26.hr0.hc25) specimen. it's clearly that the hybridization in strength of concrete led to increase the post-cracking stiffness of specimen. plate 2 mode of failure and cracks pattern of specimen os.h26.hr0.hc25 figure 3 load deflection response of os.h26.hr0.hc25 specimen specimen os.h26.hr0.hc50 this slab specimen was made from hybrid strength concrete by casting layer of hsc of 50 mm thickness in compression zone monolithically over layer of nsc of 50 mm thickness in tension zone. traditional steel bars was used to reinforce this specimen in tension zone. first visible crack was observed at load about (26.5 kn) (29.3 % of ultimate load) in the maximum moment region. compared with the control (os.h26.hr0.hc0) specimen and (os.h26.hr0.hc25) specimen, cracking load was higher by about 26.5% and 15.2% respectively. this increasing is due to the increase in the moment area (uncracked al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 222 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. moment of inertia) of section due to the increasing of the compressive strength of the compression zone. with increasing of load, cracks of flexural shear expanded to the shear span. some of these cracks depth was increased gradually and tended to incline towards the points of loading. with increasing of applied load, major diagonal shear crack was opening up over the entire width of slab until the final shear failure was took place at (90.3 kn) as shown in plate 3 larger than the control (os.h26.hr0.hc0) specimen by about 14.74%. the increase in ultimate load is due to the change in the internal couple lever arm. figure 4 illustrates load deflection curve for this specimen. plate 3 mode of failure and cracks pattern of specimen os.h26.hr0.hc50 figure 4 load deflection response of os.h26.hr0.hc50 specimen specimen os.h26.hr0.hc75 same as other specimens this test group, os.h26.hr0.hc75 specimen was made from hybrid strength concrete by casting layer of hsc of 75 mm thickness in compression zone monolithically over layer of nsc of 25 mm thickness in tension zone. traditional steel bars was used to reinforce this specimen in tension zone. first visible crack was flexural cracks observed at significantly higher load of about (27 kn) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 223 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (29.4% from ultimate load) at the tension face within constant moment region. comparing with reference os.h26.hr0.hc0 specimen, first cracking load was higher by 28.6%. subsequent increasing in applied load led to formation of several flexural and flexural shear cracks and the constant moment region become heavily with cracks as shown in plate 4. with advance stages of loading, main flexural shear crack opening up and propagate rapidly until flexural shear failure was occur at load of (91.8 kn) which consider more ductile failure with respect to reference slab os.h26.hr0.hc0. figure 5 illustrate load deflection response of this specimen. plate 4 mode of failure and cracks pattern of specimen os.h26.hr0.hc75 figure 5 load deflection response of os.h26.hr0.hc75 specimen from figure 6, it can be noticed that the stiffness of specimen increased when the concrete compressive strength of compression zone increased also with increasing the depth of hsc in compression zone (ratio of hybridization). this behavior attributed to the flexural rigidities of hybrid strength concrete (hysc) slabs are higher than nsc slabs, these slabs exhibit smaller curvature and deflection and therefore narrower cracks. as illustrated in plates (1, 2, 3 and 4), crack spacing of hysc slabs were found to be larger than nsc slabs because the difference in elastic properties of the two types of concrete. first cracking load of hysc slabs were significantly higher than nsc slab ranged between (9%-28.6%) due to the significantly increasing in uncracked moment of inertia. also, the ultimate load carrying capacity of the hysc slabs were significantly higher than nsc slabs by 14.75% and 16.7% for os.h26.hr0.hc50 and os.h26.hr0.hc75 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 224 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. slab specimens respectively and slightly lower than nsc by 5% for os.h26.hr0.hc25 because of the splitting bond failure between the two layers of hsc and nsc. however, the precocious shear failure prohibited the slab specimens from attaining their ultimate flexure strength because the holes make section weaker in shear. figure 6 load deflection response of os.h26.hr0.hc75 specimen 3.2. ductility ductility is usually welldefined as the energy that absorbed by the materials up to the failure has been completed [13]. in the current study, ductility factors are evaluated according to the vertical disp. at ultimate load divided by vertical disp. at the service load [14]. as listed in table 6, it can be noticed that for specimens (os.h26.hr0.hc25,os.h26.hr0.hc50 and os.h26.hr0.hc75), ductility was increased by 25%, 31.25% and 60% respectively comparing with os.h26.hr0.hc0, this increasing in ductility is due to the increasing in ultimate load capacity resulted from the hybridization in strength of concrete that led to increasing ultimate deflection. 4. conclusions based on the experimental study carried out here for simply supported one way hollow core slabs, the following conclusions can be drawn within scope of this research: 1. presence of high strength concrete layer in the compression zone and its ability to sustain high compressive force in general, lead to increase the stiffness of slab, the cracking load and load carrying capacity, while the deflection decreases at the same load. this behavior may be attributed to increasing of un-cracked moment of inertia and the internal lever arm. 2. for one-way hcs group. cracking load and ultimate shear strength are increased about (26%-29%) and (16%-17%) respectively for tested slab with 50 mm and 75 mm thickness of hsc top layer respectively. these smaller increases in ultimate load may be attributed to remaining the tension zone of slab constructed with nsc. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 225 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. the best results of hybrid strength system for one way slab group were obtained from slab with 50 mm thickness of hsc top layer. from experimental results mentioned in chapter four, it can be noticed there is a slight difference in the ultimate shear strength between this model and the other constructed with 75 mm thickness of hsc top layer, therefore, this model regard a best hybrid strength model with respect to structural and economical purposes. 4. the tested specimens constructed with hybrid strength concrete exhibited an increase in ductility between (25%-60%). 5references 1. fukuyama h., matsuzaki y., sato m. and suwada h., "structural performance of engineered cementitions composite elements", proceedings of 6th asccs conference, asccs-6 secretariat, march 2000, pp 969–976 2. kawamata a., mihashi h. and fukuyama h., "properties of hybrid fiber reinforcement cement-based composites", journal of advanced concrete technology, vol. 1 (2003) no. 3 p 283-290, japan 3. kheder, g. f., al kafaji, j. m. and dhiab, r. m., "flexural strength and cracking behavior of hybrid strength concrete beams", materials and structures journal, 2010, vol. 43: 1097-1111, doi 10.1617/s11527-009-9569-9 4. 30. pisanty, a., 1992 "the shear strength of extruded hollow-core slabs", materials and structures, 25: 224-230 5. aci-318-11, acicommittee, "building code requirements for structural concrete",aci-318m14.and.commentary aci-318m-14, american concrete institute. 6. fip recommendations, "precast prestressed hollow core floors", fip, 1988 7. mansor aah (2001) flexural cracks in high-strength reinforced concrete beams. msc thesis, almastansiriya university, college of engineering, march 2001, p 111 8. iraqi specification standards iqs no. 5, 1984 "portland cement", central agency for standardization and quality control, planning council, baghdad, iraq 9. iraqi specification standards iqs no.45, 1984 "aggregate from natural sources for concrete and construction", central agency for standardization and quality control, planning council, baghdad, iraq 10. astm c33-13 "standard specification for concrete aggregates", american society for testing and materials, 2013 11. astm c 494/c 494m-05, 2005 "standard specification for chemical admixtures for concrete", annual book of astm standards, american society for testing and materials, vol. 04. 02. 12. british standard institution (1997), "concrete. methods for specifying concrete mixes", bs 5328-2 13. hussain, m., alfarabi, s., basunbul a., baluch m.h., al-sulaimani g.j., "flexural behavior of precracked reinforced concrete beams strengthened externally by steel plates" aci structural journal, vol.92, issue.1, 1995. 14. jeffrey s. russell "prestrectives in civil engineering", commemorating the 150th anniversary of the american society of civil engineering, asce publications, 2003. p.375. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 593 behavior 0f high strength concrete beams using risen epoxy msc. hayder a. al-khazraji1 msc. fatin i. al-hydery2 1.assistant lecturer,college of education, university of maysan. 2.assistant lecturer college of education, university of maysan abstract reinforced concrete beams for high-strength concrete often exhibit structural and nonstructural cracking due to variety steel reinforcement. four reinforced concrete beams with dimensions of (120*230*2550)mm were investigated. beams (1&2) have tensile steel ratio (0.0099), while beams (3&4) have tensile steel ratio (0.018). deflections were measured at first third, second third and mid span for original repaired beams using dial gauges with accuracy 0.01 mm. the repair strength achieved for risen epoxy injection high-strength reinforced concrete beams was shown similar that original beams, but a little deference. the failure load for repaired beams higher than original beams. keywords: compressive strength: concrete: high-strength concrete: risen epoxy: deflection اومة باستخدام ايبوكسي الراتنج تصرف الجسور الخرسانية عالية المق حيدر عبد راضي الخزرجي. م.م فاتن إبراهيم موسى الحيدري. م.م 1 2 الخالصة أربع عتبات خرسانية .العتبات الخرسانية المسلحة عالية المقاومة ترسم تشققات إنشائية وغير إنشائية تبعا لتنوع حديد التسليح بينما ) 0,0099(تمتلك نسبة حديد تسليح في منطقة الشد ) 2 و 1(العتبات .صهاتم فح) ملم2550*230*120(مسلحة بأبعاد االنحرافات التي قيست في الثلث األول والثلث الثاني ومنتصف ). 0,018(نسبة حديد التسليح في منطقة الشد ) 4 و 3(العتبات يبوكسي الراتنج المحقون للعتبات الخرسانية مقاومة التصليح ال. ملم0,01العتبات األصلية والمصلحة باستخدام مقاييس بدقة .حمل الفشل للعتبات المصلحة اكبر من العتبات األصلية.المسلحة نفس مقاومة العتبات األصلية لكن باختالف قليل al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 594 introduction: the cracks may represent the total extent of the damage, or pointing to greater magnitude of problems. their significance depends on the type of structure, as well as the nature of the cracking. for example, the cracks which acceptable for buildings may not be acceptable in water retaining structures. the proper repair of cracks depends on knowing the causes and selecting the repair procedures that take these causes into account; except that, the repair may be temporary only. successful longterm repair procedures must cure causes the cracks as well as the cracks itself. generally, the kind of the cracks that attack concrete classify according to its stiffening; cracking of plastic concrete and cracking of hardened concrete. plastic shrinkage, the crack of plastic concrete occurs when subjected to a very rapid loss of moisture caused by a combination of factors which include air and concrete temperatures, relative humidity and wind velocity at the surface of the concrete. the another type is the crack of hardened concrete which have many sort; drying shrinkage, thermal stresses, chemical reaction, weathering, construction overloads and errors in design. a common cause of cracking in concrete is restrained drying shrinkage. 1. drying shrinking is caused by the loss of moisture from the cement paste constituent, which can shrink by as much as 1 percent (1). 2. thermal stresses, which accrue when the temperature differ within the concrete structure. when the tensile stresses due to the differential volume changes exceed the tensile stress capacity, the concrete will crack. 3. chemical reaction may cause cracking of concrete. these reactions due to materials used in concrete or materials that come into contact with the concrete after it has hardened (aci 201.2r). 4. weather can cause cracking include; freezing and thawing, wetting/drying and heating/cooling(1). 5. construction overloads can often be far more severe than those experienced in service. these conditions may occur at early ages, when the concrete susceptible to damage and they often result in permanent cracks. 6. errors in design/detailing, these effects range from poor appearance to lack of serviceability to catastrophic failure. predication of immediate deflection of reinforced concrete beams after repairing the cracks using injection of risen epoxy and studying effecting reinforcement ratio at tension and compression zone on this deflection. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 595 selection of repair procedures: based on the careful evaluation of the extent and cause of the cracking, procedures can be selected accomplish one or more of the following objectives: 1. restore and increased strength; 2. restore and increased stiffness; 3. improve functional performance; 4. provide water tightens; 5. improve appearance of the concrete surface; 6. improve durability, and 7. prevent development of corrosive environment at reinforcement. depending on the nature of the damage, one or more repair methods may be selection for example, tensile strength may be restored across a crack by injecting it with epoxy or other high strength bonding agent. however, it may be necessary to provide additional strength by adding reinforcement or using post tensioning. epoxy injection alone can be used to restore flexural stiffness if further cracking is not anticipated (aci 503 r). cracks causing leaks in water-retaining or other storage structures should be repaired unless the leakage is considered minor or there is an indication that the crack is being sealed by autogenously healing. repairs to stop leaks may be complicated by a need to make the repays while the structures are in service. cosmetic considerations may require the repair of cracks in concrete. however, the crack locations may still be visible and it is likely that some from of coating over the entire surface may be required. to minimize future deterioration due to the corrosion of reinforcement, cracks exposed a moist or corrosive environment should be sealed. the key methods of crack repair available to accomplish the objectives outlined are described later. following the evaluation of the cracked structure, a suitable repair procedure can be selected. successful repair procedures take into account the cause(s) of the cracking. for example, if the cracking was primarily due to drying shrinkage, then it is likely that after a period of time the cracks will stabilize. on the other hand, if the cracks are due to a continuing foundation settlement, repair will be of no use until the settlement problem is corrected (2). this article provides a survey of crack repair method, including a summary of the characteristics of the cracks that may be repaired with each procedure the types of structures that have been repaired, and summary of the procedures that are used readers are also directed to aci 546.1 r and aci compilation no-5(1980), which specifically address the subject of concrete repair ( ). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 596 instrument used in testing: 3.1flexural machine ( mfl system) by using two point load mode ( capacity = 3000 kn). 3.2dial gauges ( with accuracy 0.01 mm). 3.3srain gages. all the above instruments are shown in fig (1) during the testing. epoxy injection implemented in this work cracks are narrow as 0.002 in (0.05 mm) can be bonded by the injection of risen epoxy. the technique generally consists of establishing entry and venting ports at close intervals along the cracks, sealing the crack on exposed surface and injecting the epoxy under pressure. epoxy injection has been successfully used in the repair of cracks in buildings, bridges, dams and other type of concrete structures. however, unless the cause of the cracking has been corrected, it will probably recur near the original crack. if the cause of the cracks cannot be removed than two options are available. one is to rout and seal the crack, thus treating it as a joint or establish a joint that will accommodate the movement and inject the crack with epoxy or other suitable material. with the exception of certain moisture tolerant epoxies, this technique is not applicable if the cracks are actively leaking and cannot be dried out. wet cracks can be injected using moisture tolerant materials, bit contaminants in the cracks ( including silt and water) cam reduce the effectiveness of die epoxy 10 structurally repair the cracks. the use of a low-modulus, flexible adhesive in a crack will not allow significant movement of the concrete structure. the effective modulus of elasticity of a flexile adhesive in a crack is substantially the same as mat of a rigid adhesive because of the thin layer of material and high lateral restraint imposed by the surrounding concrete. epoxy injection requires a high degree of skill for satisfactory execution and application of the technique may be the limited by the ambient temperature. the general procedures involved in epoxy injection are as follows: clean the cracks, the first step is to clean the cracks that have been contaminated; to the extent this is possible and practical. contaminants such as oil, grease, din or fine particles of concrete prevent epoxy penetration and bonding and reduce the effectiveness of repairs. preferably, contamination should be removed by vacuuming or flushing with water or other especially effective cleaning solutions. the solution is then flushed out using compressed air and a neutralizing agent or adequate time provided for air drying it is important. however, to recognize it practical limitations of accomplishing complete crack cleaning. a reasonable evaluation should be made of the extent and necessity of cleaning trail cleaning may be required. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 597 seal the surfaces, surface cracks should be sealed to keep the epoxy from leaking out before it has gelled the crack face cannot be reached but where there is backfill, or where a slab-on-grade is deign repaired, the backfill material or sublease material is sometimes an adequate seal. however, such a condition can rarely be determined in advance and uncontrolled injection can cause damage such as plugging a drainage system. extreme caution must therefore be exercised when injection cracks that is not visible on all surfaces. a surface can be sealed by applying an epoxy, polyester or other appropriate sealing material to the surface of the crack and allowing it harden. if a permanent glossy appearance along the crack is objectionable and if high injection pressure is not required a strippable plastic surface sealer may be applied along the face of the crack. when die job is completed, the surface sealer can be stripped away to expose the gloss free surface. compendious seals can also be used where appearance of the completed work is important. if extremely high injection pressures are needed, the crack can be cut out to a depth of 1/2 in (13 mm) and width of about 3/4 in (20 mm) in a v-shape filled with an epoxy and struck off flush with the surface. install the entry and venting pones, three methods are in general use: a. fittings inserted into drilled holes. this method was the first be used and is often used in conjunction with v-grooving of the cracks. the method entails drilling a hole into the crack, approximately 3/4 in (20 mm) in diameter and 1/2:1 in (13 to 25 mm) below the apex of the vgrooving section into which a fining such as a pipe nipple or tire valve stem is usually bonded with an epoxy adhesive. a vacuum chuck and bit or a water-cooled core bit is useful in preventing the cracks from being plugged with drilling dust. b. bonded flush fitting. when the cracks are not v-grooved, a method frequently used to provide an entry port is bond a fitting flush with the concrete face over the crack. the flush fitting has an opening at the cop for die adhesive enter and a flange at the bottom chat is bonded to the concrete. c. interruption in seal another system of providing facture’s instructions, usually with the use of a mechanical stirrer like a paint mixing paddle. care must be taken to mix only the amount of adhesive that can be used prior to commencement of gelling of the material. when the adhesive material begins to gel its flow characteristics begin to change and pressure injection becomes more and more difficult. in discontinuous mixing system, the two liquid adhesive components pass through metering and driving pumps prior to passing through an automatic mixing head. the continuous mixing system allows the use of fast setting adhesives that have a short working life. • inject the epoxy. hydraulic pumps, paint pressure pots or air-actuated caulking guns may be used. the pressure used for injection must be selected carefully, increased pressure often dose little accelerate the rate of injection. in face, the use of excessive pressure can propagate the existing cracks causing additional damage. if crack is vertical or inclined, the injection process should begin by pumping epoxy into the entry port at the lowest elevation until the epoxy level reaches the entry port above. the lower injection port is then capped and the process is repeated until the crack has been completely filled and all ports have been capped. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 598 for horizontal cracks, the injection should precede from one end of the crack the other in the same manner. the crack is mil if the pressure can be maintained. if the pressure can not be maintained the epoxy is still flowing into unified portions or leaking out or the crack. • remove the surface seal, after the injected epoxy has cured, the surface seal should be removed by grinding or other means as appropriate. • alternative procedure. for massive structures, an alternate procedure consists of drilling a series of holes [ usually 7/3 to 4 in (20 to 100 mm) diameter] chat intercepts the crack at a number of locations. typically, holes are spaced at 5 ft(1.5m) intervals. another method recently being used is a vacuum or vacuum assist method. her are two techniques: one is to entirely enclose the cracked member with a bag and introduce the liquid adhesive at the bottom and to apply a vacuum at the top. the other technique is to inject the cracks from one side and pull a vacuum from the other. typically, epoxies are used; however, acrylics and polyester have proven successful. experimental work: selection of materials: the production of high –strength concrete requires high quality materials. moreover, high-strength concrete mix design proportioning is more critical than the design of normal – strength concrete mixtures, therefore special attention must be given to control the water cement ratio (w/c) in the mix. usually chemical admixtures (super plasticizers) are employed to obtain a low (w/c) ratio. the following is the detailed description of the materials used: cement: the proper selection of the type and source of cement is one of the most important steps in the production of high – strength concrete. opc type i was used. fine aggregate: the grading and particle shape of fine aggregate are significant factors in the in the production of high –strength concrete. fine aggregate with a rounded particle shape and smooth texture with a fine ness modulus, specific gravity , and absorption of 2.48 , 2.66 , and 2% , respectively . natural sand from alrahalia region is used. the sand complies to iqs 45: 1984 coarse aggregate: the ideal coarse aggregate should be clean, cubical , angular 100% crushed aggregate with a minimum of flat and elongated particles . crushed gravel from alnibaee region is used with maximum size of 14 mm. the specific gravity and absorption are 2.66 and 0.66 % , respectively . water: tap water is used for both mixing and curing of concrete. admixtures: a super plasticizer admixture used in this study is a me lament l–10(melamine for maldehyde condensate). its properties are listed in table (1). because of the capability of more than 12 percent water reduction, this material is classified as type f in astm c494. reinforcing steel: all the reinforcing steels are deferred from the same source. table (2) gives the results of testing 200 mm long sample from size bars (8, 10, 12, and 16 mm). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 599 concrete mix:all reinforced concrete beam have same mix. table (3) shows this mixture. type of epoxy: low viscosity epoxy injection resin system uses : for injecting into cracks in concrete or masonry to form a permanent bond or seal. advantages : • low viscosity allows penetration into the finest cracks. • formulated for hot climates. • suitable for structural repairs. • excellent bond to concrete, brick and masonry. • minimum creep under sustained loud. • resistant to wide range of chemicals. • non-shrink. adheres with no less of bond. description: contexture epoxy two parts. solvent – free. low viscosity to resin system is mixed in the proportions supplied to form a strong permanent bond and seal in cracks in concrete and masonry . contexture epoxy is designed to be injected into cracks using suitable resin injection equipment. design criteria: contexture epoxy is designed to seal and bond cracks in concrete and masonry. crack width of between 0.2 mm and 9 mm can be treated . specification: the epoxy crack injection resin system shall be contexture epoxy, a two part solvent – free low viscosity, epoxy, when mixed in the proportions supplied and injected into cracks in concrete the resin shall form a permanent bond and seal in both dry and damp conditions. properties: the following properties were obtained at a temperature of 35c˚ and at 7 days unless other wise specified in table (4). instructions for use: contexture can be applied using either injection packers fixed into holes drilled directly into the crack or drilled diagonally from concrete adjacent to the crash or by the fixing of injection nipples . bonded to the surface using nitra or tar ( fc ) . al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 600 preparation: clean the surface and remove any dust, unsound or contaminated material , plaster , oil , paint grease , corrosion deposits or algae , the surface should preferably using high pressure water jetting or light abrasive blasting , following particles by thorough washing to remove dust and remaining particles . dirt a lone may be removed with wire brushes or similar mechanical means, oil and grease deposits should be removed me steam cleaning detergent scrubbing or the use of a proprietary degreaser the effectiveness of decontamination should be assessed by a pulloff test. blow the cracks and treated surface with oil free air to ensure complete removal of all dust and loose particles, ensure that the surfaces are blown dry . in the presence of running water the flow must be stopped using contexture which produces rapid setting water – stopping foam. when the water is stopped the cracks are re-injected with contexture. fixing injection packers: the injection packers shall be in sorted into perdrilled holes at intervals along the length of each crack. the distance between each packer will depend upon the width and depth of the crack. so acing shall be close enough to ensure that the resin will penetrate along the cracks between the packers shall be sealed with a band of nit mortar ( fc) 30 to 40 mm width and 2 to 3 mm thickness . both sides of any cracks which go all the way through a wall or slab shall be sealed in this way . in the case of a wall or slab cracked all the way through packers shall be located on both sides with those at the back placed at midway points between those at the front . the nit mortar fc shall be allowed to cure for 3 hours at 35 c . at low ambient temperatures (5c to 12c) the curing time will be extended and the applicator shall ensure that the surface sealant has adequately cured prior to continuing . one end of the injection hose shall be attached to the lowest packer on vertical cracks or to either end of the horizontal cracks. alternative methods of resin injection are currently to use they include the system where injection nipples are bonded to the substrate. testing procedure: the beam under test was implying supported over a span of 2550 mm. two equal point loads, were applied to the third-points of the beam by a part of hydraulic jacks. first, second third and mid-span deflections of the beam were measured with a dial gauges. loading was increased by small increments until the beam cracked. after each increments of loading, the deflections were recorded and the propagation of crack was examined. the damaged beam was then repaired by injecting the cracks full depth with a low viscosity, fastcuring, slump-pumping liquid epoxy adhesive after cleaning the surface and remove any dust. the surface should be preferably using high pressure water jetting or light abrasive blasting. following particles through washing to remove dust and remaining particles. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 601 the perimeter of each cracked section was sealed off with either a rapid-setting epoxy adhesive or temporary seal, leaving several small holes for the subsequent injection and relief of the structural adhesive when the surface seals had cured, the epoxy adhesive was injected into the cracks. only the major cracks were treated in this way. the minor cracks, being less than ( 0.05)mm were too fine for complete penetration of the structural epoxy the crushed concrete in the compression zone of the beam was repaired in a similar manner. the repaired beam was left at ambient temperature for five days and the tested to failure as before. measurements of deflections are done by dial gauges under 2/3 and 1/3 of span. these dial gauges are with an accuracy of 0.01 mm and strain gauges were located under mid of beams and distributed on the beam's faces. shown in figure(1), figure(2) and table (5) showed the details of beam sections. test results throughout this testing we can results, the behavior of the repaired beams was similar to that of the pre-crack beams, but a little deference for all beams(b1, b2, b3 and b4) under loading, the repaired cracks did not reopen-instead, new cracks were formed some being ad adjacent to the old ones. at failure concrete crushing occurred away from the epoxy-repaired region. figs.(3,4,5,6) show that load deflection curve relationship for beams b1,b2,b3 and b4. plate (1, 2 and 3) show injection of epoxy and cracks of beams. conclusion 1 the proper repair of cracks depends on known of the cases and selecting the best repair procedure. 2in this research show that the compression steel ratio ρ ′ =0.0049 or ρ ′ =0.0099 for beams 1 and 2 there was no affecting on deflections so as beams 3 and 4 while affecting tensile steel ratio ρ was greater than ρ ′ for all beams. 3the repair procedure should accomplish one or move of the following objectives increased strength and staffers, improve performance apron cave , water tireless , and durability . 4epoxy ejection in found proper method to restore strength of stiffness of the crack number. 5load deflection, curves of the repaired its beams were found of similar or improved behavior to those of per-cracked beam. 6the failure load of the spiciness in general when approaching or any is higher than those of the origins pre-cracked beams. 7finally, it may be conclude that the epoxy ejection method of crack repair is found effecting in restoring the original structure and stiffness. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 602 references 1aci committee 363 “ state-of – the – art report on high-strength concrete” , aci journal , vol . 81 , no . 4 , july –august, 1984 pp. 364-411 . 2aci committee 211, “ guide for selecting properties for high – strength concrete with portland cement and fly ash “ , aci materials journal ,vol.90,no .3 may – june 1993, pp. 272-283. .8 ، صفحة 1984الجھاز المركزي للتقییس والسیطرة النوعیة ، بغداد ، " السمنت البورتالندي " 5/ المواصفات العراقیة -3 الجھ از المرك زي للتقی یس وال سیطرة " ركام المصادر الطبیعیة المستعمل في الخرس انة والبن اء :" 45/ المواصفات العراقیة -4 .1984النوعیة ، بغداد ، 5astm designation c494-86, “ chemical admixtures for concrete “ , 1989 annual book of astm , standards american society for testing and materials philadelphia , pennsylvania , section 4,vol.04-02, pp.248-255 . 6astm designation c39-86 “ compressive strength of cylindrical concrete specimens “ , 1989 annual book of astm , standard american society for testing and materials philadelphia , pennsylvania , section 4 , vol. 04=02, pp.20 -24 . 7astm designation c469-87a; “ static modulus of elasticity and poison’s ratio of concrete in compression “ 1984 annual book of astm , standard american society for testing and materials philadelphia , pennsylvania , section 4, vol.04-02;pp . 236-236 . 8bs 5328 : part 2 : 1991 : method for specifying concrete mixes . 9aci 211: part 1 : standard practice for selecting proportions for normal , heavy weight , and mass concrete. 11-causes , evaluation and repair of cracks in concrete structures, ( reported by aci committee 224 ( aci 224 . ir-93 ) ( reap proved 1998 ) . 12-long – term deflection of height strength r.c beams . hayder abd radhi al-khazrayi 2001. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 603 table (1) properties of the super plasticizer* 1 main action concrete 2 subsidiary effect hardening accelerator 3 appearance clear to slightly milky 4 solid in aqueous solution. approx. 20% 5 density 1.1 g/cm3 6 chloride content less than 0.005% 7 sugar content none 8 handling no special precautions 9 ph valve 7-9 10 frost resistance element l-10 with stands any number of frost cycles. it should be thoroughly thawed before use 11 storage life at least two years. it should not , however , be exposed to excessive heating *properties obtained from product catalogue table ( 2 ) properties of reinforcement.* nominal diameter (mm) measured diameter (mm) area (mm) length (mm) elongation % modulus of elasticity ( gpa ) fu mpa fu mpa 8 8.01 50.4 200 11.4 213 532.4 602.7 10 10.0 78.5 200 11.9 210 611.9 725.8 12 12.1 114.9 200 14.0 215 534.3 634.5 16 15.97 200.2 200 12.5 204 594.6 784.4 * testing was made at the laboratory of materials in baghdad university, college of engineering al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 604 table ( 3 ) concrete mix proportions ( kg/m-3 ). w/c ratio water cement sand gravel s.p * 0.27 162 600 664 996 24 *super plasticizer table ( 4 ) properties of epoxy. no test method typical results 70.0 n/mm2 @ 20c 1 compressive strength 93.0 n/mm2 @ 35c 2 tensile strength 26.0 n/mm2 @ 35c 3 flexural strength 63.0 n/mm2 @ 35c 4 young’s modulus in compression 16 gpa. 90 minutes @ 20 c 5 pot life 40 minutes @35c 6 specific gravity 1.04 7 fixed viscosity 1.0 poise @ 35c table (5) details of beam sections. tension zone compression zone dimension beam no. ρ′ dim. mm ρ ′ dim. mm b d h fc′ mpa fy mpa fu mpa es gpa b1 0.0099 2ø12 0.0049 1ø12 120 191 230 71 534 634 125 b2 0.0099 2ø12 0.0049 2ø12 120 191 230 69 534 634 125 b3 0.018 2ø16 0.0 0.0 120 189 230 62 594 784 204 b4 0.018 2ø16 0.0069 2ø10 120 189 230 65 594 784 204 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 605 figure (1): beam specimens test and dial gauges with accuracy 0.01 mm. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 606 figure (2): details of beam section. 0049.0=′ρ 0099.0=ρ 0099.0=ρ 0099.0=′ρ 0069.0=′ρ 018.0=ρ h=230mm b4 d= 189mm b= 120mm d b 00.0=′ρ h=230mm d b 018.0=′ρ b3 d= 189mm b= 120mm al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 607 plate (1) injection of epoxy for beams. plate (2) cracks of beam after loading. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 608 plate (3) mish of cracks after loading. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 609 0 100 200 300 400 500 600 deflection (mm) 0 5 10 15 20 25 30 35 40 45 50 55 lo ad (k n) load deflection curve 1/3 l 2/3 l 1/2 l figure (3) load-deflection relationship b1. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 610 0 100 200 300 400 500 600 deflection (mm) 0 5 10 15 20 25 30 35 40 45 50 55 lo ad (k n) load deflection curve 1/3 l 2/3 l 1/2 l figure (4) load-deflection relationship b2. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 611 0 100 200 300 400 500 600 700 800 900 deflection (mm) 0 5 10 15 20 25 30 35 40 45 50 55 lo ad (k n) load deflection curve 1/3 l 2/3 l 1/2 l figure (5) load-deflection relationship b3 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 612 0 100 200 300 400 500 600 700 800 900 deflection (mm) 0 5 10 15 20 25 30 35 40 45 50 55 lo ad (k n) load deflection curve 1/3 l 2/3 l 1/2 l figure (6) load-deflection relationship b4. <dad1c8ed2e706466> ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٠ اثر عامل السكن ومساحة المسكن على المستوى الدراسي للتلمیذ ومقارنتھ بعامل استقاللیة المدرسة ٠٧٨١٣٣٣٢٩١٣م.م. غیاث حمزة علي / التربیة في محافظھ كربالء المقدسةمدیریة eng_ghayath@yahoo.com الخالصة الھ��دف م��ن ھ��ذه الدراس��ة ھ��و تس��لیط الض��وء عل��ى اث��ر عام��ل الس��كن ومس��احة المس��كن والعالق��ة بین��ھ وب��ین االداء الدراس��ي للتلمی��ذ ھو استقاللیة المدرسة على االداء الدراس�ي لتالمی�ذ المرحل�ة االبتدائی�ة . لتحقی�ق ذل�ك ت�م اخ�ذ ومقارنة اثر ذلك العامل مع عامل اخر لتالمیذ الصف السادس االبتدائي من المدارس الواقعة ضمن الرقع�ة الجغرافی�ة لمحافظ�ة ك�ربالء المقدس�ة ٧٢عینة عشوائیة حجمھا تلمی�ذ م�ن مدرس�ة ذات دوام ثالث�ي وم�ن ٢٥رس�ة ذات دوام ثن�ائي وتلمی�ذ م�ن مد ٣٢تلمیذ م�ن مدرس�ة ذات دوام اح�ادي و ١٥بواقع ض�من االس�رة ف�ي المس�كن وتقس�یم المس�احة االرض�یة للف�رد الواح�د المعلومات الواردة في البطاق�ة المدرس�یة لك�ل تلمی�ذ ت�م حس�اب فئات اعتمادا على ذلك، كما تم تس�جیل المع�دل الع�ام لالمتحان�ات النھائی�ة (البكالوری�ا) لك�ل تلمی�ذ . ت�م تحلی�ل البیان�ات ٦التالمیذ الى وتحلی�ل التب�این التي تم جمعھا باستخدام االحصاء الوصفي واالستداللي بواس�طة حس�اب االوس�اط الحس�ابیة واالنحراف�ات المعیاری�ة ) لمعدالت التالمی�ذ . توص�لت الدراس�ة ال�ى وج�ود فروق�ات ذات دالل�ة احص�ائیة ب�ین مع�دالت التالمی�ذ تع�زى anovaاالحادي ( مساحة المسكن ، وعدم وجود فروقات ذات داللة احصائیة بین معدالت التالمیذ تعزى الستقاللیة المدرسة . لمتغیر ن ، االسكان االقتصادي ، بناء المساكن ، مساحة المسكن ، االداء الدراسي ، استقاللیة المدرسة الكلمات المفتاحیة : سوق االسكا . the impact of housing and living space on school level of the pupil and compared to a factor of independent school ghayath hamza ali/ assistant lecturer directorate general of education in karbala province 1. abstract this study is about the impact of housing factor and house area on school performance of the pupil and compared the impact of this factor with another factor is the independence of the school on the school performance of primary school pupils . to achieve this was taking a random sample of 72 sixth graders from primary schools located within the geographical area of the governorate of karbala by 15 pupils from a school single -time and 32 pupils from a school dual-time and 25 pupils from a school three-time. from the information contained in school records per pupil, floor space per person within the household in the dwelling was calculated then the students divided into six categories depending on it, the overall average was recorded for the final exams (bac) per pupil. data collected were analyzed using descriptive and inferential statistics by calculate the weighted mean, standard deviation and anova to the pupils rates . the study found that there are significant differences between the pupils rates due to the variable of house area, and the lack of statistically significant differences between the rates of pupils due to the independence of the school. keyword: housing market, affordable housing, housing construction, housing space, school performance, school independence . ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣١ المقدمة عام�ل الس�كن السكن لدیھ القدرة على التأثیر على المخرجات التعلیمیة للسكان والمجتمعات والفھم االفضل لت�اثیر على المخرجات التعلیمیة یساعد على وضع السیاسات االسكانیة المناسبة لتحسین نوعیة حیاة الس�كان بش�كل ع�ام التعلیمي ربما یقدم الفرص للمؤسسات االسكانیة والتعلیمی�ة ، اضافة الى ان تدارس الصلة بین االسكان و المنجز ك .للتعاون فیما بینھا للوصول الى الھدف المشتر ھناك العدید من المسارات التي یؤثر السكن من خاللھا على المخرجات التعلیمیة عل�ى وج�ھ الخص�وص فت�نقالت السكن العالیة وظروفھ السیئة مثل االكتظاظ وانع�دام الخصوص�یة تقت�رن م�ع عج�ز كبی�ر ف�ي التحص�یل العلم�ي . ال الن��وعین م��ن التالمی��ذ المتنقل��ین وغی��ر ت��نقالت الس��كن ھ��و عام��ل مھ��م الن��ھ ی��ؤثر عل��ى المخرج��ات التعلیمی��ة لك�� المتنقلین فقد وجد ان ھناك صلة مباشرة بین استقرار السكن م�ع االداء الدراس�ي فت�نقالت الس�كن العالی�ة غالب�ا م�ا تك��ون مص��حوبة م��ع عالم��ات متدنی��ة و ارتف��اع مع��دالت الرس��وب و م��ع ارتف��اع مع��دالت التس��رب م��ن الم��دارس ال����ة ملكی����ة المس����كن لھ����ا اث����ار ولك����ن ص����غیرة عل����ى المخرج����ات التعلیمی����ة الثانوی����ة كم����ا ان الج����وار وح )scanlon,2001.( من العوام�ل المھم�ة االخ�رى الت�ي ت�ؤثر بش�كل كبی�ر عل�ى المخرج�ات التعلیمی�ة ھ�و االكتظ�اظ ال�ذي یع�رف بان�ھ یم لالطف�ال فق�د المسكن مع اكثر من شخص واحد في الغرفة الواحدة . فاالكتظاظ لھ ت�أثیر ض�ار عل�ى نت�ائج التعل� وجد ان االطفال الذین یعیشون في مساكن مزدحمة یكونون اقل احتم�اال التم�ام الدراس�ة الثانوی�ة بش�كل ملح�وظ ، ). فاالطف�ال ال�ذین braconi,2001% مقارنة مع اق�رانھم (٧% الحتمال التخرج والبنات اقل ب ١١االوالد اقل ث�ور عل�ى ام�اكن دراس�ة مناس�بة التم�ام واجب�اتھم الیومی�ة یعیشون في مساكن مزدحمة قد یج�دون ص�عوبة ف�ي الع ) .evans,2001ویرجح ان یعانون من مشاكل نفسیة وصحیة تضر باداءھم المدرسي ( خصائص االسكان وانماط االشغال في العراق االق�ل نوع الوحدات السكنیة السائدة في العراق ھي المساكن التقلیدیة التي تكون موصولة على جان�ب واح�د عل�ى % م��ن ٦٥وق�د بین��ت الدراس��ة ان ح��والي ٢٠٠٦حس�ب الدراس��ة الت��ي قام��ت بھ�ا وزارة االس��كان واالعم��ار س��نة الوحدات السكنیة في العراق ھي من ھذا النوع . ھذه المساكن تختلف في احجامھا الى حد كبیر حیث ان مساحتھا یوضح )١الجدول رقم (. ٢م١٤٤لي حوالي ویبلغ متوسط مساحة المنزل االجما ٢م١٠٠٠إلى ٢م٣٠تتراوح بین & republic of iraq ministry of constructionاھم خصائص االسكان وانماط االشغال ف�ي الع�راق ( housing,2006(. )١جدول رقم( خصائص االسكان وانماط االشغال في العراق متوسط مساحة قطعة االرض )٢(م متوسط مساحة الوحدة السكنیة )٢(م متوسط عدد الغرف متوسط حجم االسرة % من االسر المكتظة معدل عدد االسر في الوحدة السكنیة معدل عدد االفراد في الوحدة السكنیة متوسط المساحة االرضیة للفرد ٢٥.٧ ٦.٧ ١.٢ ٥.٣ ٦ ٤.٢ ١٤٣.٩ ٢٢٦.٦ وح�دات س�كنیة مكتظ�ة % م�ن جمی�ع االس�ر ف�ي المن�اطق الحض�ریة ف�ي الع�راق یعیش�ون ف�ي٧وقد وجد ان نحو حس��ب المس��ح ال��ذي قام��ت ب��ھ وزارة االعم��ار واالس��كان ، واالكتظ��اظ ع��رف م��ن قب��ل برن��امج االم��م المتح��دة ) عل����ى ان����ھ اكث����ر م����ن ثالث����ة اش����خاص ف����ي الغرف����ة الواح����دة un-habitatللمس����توطنات البش����ریة ( )padco/un-habitat,2006.( لك��ل وح��دة األس��ر ھ��ي ع��دد االكتظ��اظ لقی��اس وھن��اك طریق��ة أخ��رى اسرة/ الوحدة السكنیة) وفقا للدراسة التي قامت بھ�ا وزارة االعم�ار واالس�كان ظ�ل ثابت�ا ١.٢وھذا الرقم( .سكنیة الص�ادر ٢٠١٤، كما ان التقری�ر الس�نوي لس�نة ١٩٨٠) في عام polserviceمنذ الدراسة التي قامت بھا شركة ( ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٢ ١.٢ا ان معدل عدد االسر في الوحدة السكنیة م�ازال ( عن وزارة التخطیط/الجھاز المركزي لالحصاء ذكر ایض ) . وھ��ذا یش��یر ال��ى ان��ھ رغ��م الح��رب والحص��ار ٢٠١٤اس��رة/ الوح��دة الس��كنیة) (الجھ��از المرك��زي لالحص��اء، االقتصادي واالضطرابات التي شھدھا القطر التي ادت الى غی�اب دور الحكوم�ة ف�ي ھ�ذا المج�ال ف�ان االس�ر ف�ي تقوم باسكان نفسھا . العراق ھي التي كانت بواسطة التعریف الثاني لالكتظاظ فانھ یمكن ان یقاس ایضا بحساب المساحة االرض�یة للش�خص الواح�د ، وعلی�ھ /ف��رد) تض��اھي المع��اییر الدولی��ة ٢م٢٥.٧ف��ان متوس��ط المس��احة االرض��یة للف��رد الواح��د ف��ي الع��راق الت��ي تبل��غ ( /ف��رد) ف��ي ٢م١٥/ف��رد) ، و(٢م١٧س��ط وش��مال افریقی��ا یبل��غ (لالس��كان حی��ث ان المتوس��ط ف��ي اورب��ا والش��رق االو ) .padco/un-habitat,2006البلدان النامیة ( التعلیم في إلسكان االقتصاديآثار ا م�ن ذوي االسكان االقتصادي ھو جزء ھام من سوق االس�كان ی�ؤمن الحمای�ة االجتماعی�ة ت�وفره الحكوم�ة لالس�ر الدخل المحدود او االسر التي یكون لدیھا اقل قوة منافسة في السوق االجتماعیة . ھناك مجموعة متزایدة من البحوث التي تشیر الى ان االسكان االقتصادي المستقر یمكن ان یوفر لالطفال امكانیة ة الرئیس�یة ف�ي تعل�یم االطف�ال . تعزیز فرص نجاحھم المدرسي بینما المدارس والمعلمین ھم من یتحملون المسؤلی تحصیل تحسین، مما یؤدي إلى المعلمین جھود یمكن أن تكملمستقرة داعمة و بیئة منزلیة تظھر ھذه األبحاث أن )lubell,2007 (.التالمیذ انتاج او اعادة تأھیل المساكن االقتصادیة قد یؤثر على المخرجات التعلیمی�ة لالطف�ال ھن�اك ع�دد م�ن الفرض�یات واعدة التي سیتم مناقشتھا بشكل مختصر فیما یتعلق بمساھمة االسكان االقتصادي في التعلیم .ال االسكان االقتصادي المستقر قد یقلل من وتیرة التحركات غیر المرغوب فیھا التي تؤدي الى ان یتعرض -١ ت��ي ت��ؤثر عل��ى االطف��ال ال��ى اض��طرابات ف��ي حی��اتھم المنزلی��ة والتعلیمی��ة : ھن��اك ن��وعین م��ن الت��نقالت ال المخرجات التعلیمیة لالطفال ؛ التنقل السكني حیث ینتقل الطفل مع اسرتھ الى منزل جدید مع او من دون تغییر المدارس والتنقل المدرسي حیث یغیر الطفل مدرستھ مع او بدون تغییر المسكن . توثق العدی�د م�ن مدرس�ة ی�تم ف�ي مراح�ل حرج�ة م�ن حی�اتھم البحوث ان تغییر االطفال لمدارس�ھم الس�یما اذا ك�ان تغیی�ر ال )beatty,2010 التعلیمیة یؤدي الى انخفاض كفاءتھم في التحصیل العلمي .( بعض استراتیجیات االسكان االقتصادي قد یساعد االسر في ان تنتقل ال�ى مجتمع�ات ل�دیھا نظ�م مدرس�یة -٢ لھ�ا ت�أثیر س�لبي عل�ى التحص��یل اق�وى واكث�ر دعم�ا للتعل�یم : ف�ي ح�ین یب�دو ان الت��نقالت المتك�ررة یك�ون التعلیمي لكن االنتقال الى المجتمعات التي تقدم نظم مدرسیة افضل او دعما اقوى للتعلیم قد یكون ل�ھ اث�ر )cohen,2011 ( ایجابي مستقل على المنجزات التعلیمیة . التي تؤدي السكن عنالتوتر الناجم وغیرھا من مصادر االكتظاظ المساكن االقتصادیة یمكن أن تقلل من -٣ بینت الدراسات وجود عالقة بین االكتظاظ وانخفاض االداء التعلیم�ي لالطف�ال ھزیلة : نتائج تعلیمیة إلى ).braconi,2001وكذلك وجود صلة بین االكتظاظ واالفتقار الى قابلیة استمرار الطفل في الدراسة ( ن ان یس�اعد االس�ر ف�ي ال�تخلص م�ن المخ�اطر تشیید وصیانة وادارة المساكن االقتصادیة بشكل جید یمك� -٤ الصحیة المرتبطة بالسكن مثل التسمم والربو التي تؤثر سلبا على التعل�یم. المس�كن غی�ر الالئ�ق یمك�ن ان یؤثر سلبا على التحصیل التعلیمي لالطفال من خ�الل مس�اھمتھ ف�ي التس�بب ف�ي االم�راض الجس�دیة الت�ي ) .centers for disease control and prevention,2011تضعف االداء التعلیمي ( المساكن االقتصادیة یمكن ان تدعم التحصیل التعلیمي لالطف�ال ع�ن طری�ق الح�د م�ن التش�رد ب�ین االس�ر -٥ الظ�روف مث�ل التعلیمی�ة الح�واجز العدی�د م�ن التش�رد الذین یعانون م�ن یواجھ األطفالالتي لدیھا اطفال : ح��ول كیفی��ة الحص��ول عل��ى والمخ��اوفوق��ت الدراس��ة، و المعرف��ي النم��و الت��ي تعی��ق الس��لبیة المعیش��یة ).wong,2009 (.العامة في المدارس لاللتحاق السجالت الشخصیة الھدف من البحث تھ��دف الدراس��ة ال��ى تس��لیط الض��وء عل��ى اھمی��ة عام��ل الس��كن ومس��احة المس��كن وعالقت��ھ بالمخرج��ات التعلیمی��ة من خالل دراسة تأثیره على المع�دالت الدراس�یة ل�بعض ط�الب الص�ف الس�ادس االبت�دائي ف�ي الم�دارس لالطفال ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٣ الواقع��ة ض��من الرقع��ة الجغرافی��ة لمحافظ��ة ك��ربالء المقدس��ة ، وك��ذلك تق��دیم بع��ض المقترح��ات ف��ي ض��وء نت��ائج لمس�كن حس�بما ج�اءت بھ�ا الدراسة لمعالجة ظاھرة تدني المعدالت الدراسیة عبر معالجة مشكلة السكن ومس�احة ا النتائج . مشكلة البحث تعتبر مشكلة ضعف المخرجات التعلیمیة من اھم المشاكل التي تواجھ الكثیر من الدول وال س�یما النامی�ة منھ�ا لم�ا لھا من عظیم االثر على التنمیة االقتصادیة لھذه الدول ویعتبر الرس�وب و اع�ادة الس�نة الدراس�یة وت�رك المدرس�ة القضایا التي تؤدي الى ھذا الضعف . من اھم وغالبا ما یؤدي تدني المعدالت لبعض التالمیذ الى رسوبھم االمر الذي یجع�ل التلمی�ذ یتس�رب م�ن المدرس�ة وم�ن ثم یصبح عالة على المجتمع باالضافة الى ما یلحقھ ذلك من ھدر للطاقة والجھد المبذول االمر الذي ی�نعكس س�لبا . على التلمیذ والمجتمع ونظرا لما لعامل السكن من قدرة على التأثیر على المخرجات التعلیمیة للسكان اض�افة ال�ى اھمی�ة دراس�ة الص�لة بینھا وبین االسكان وكذلك بینھا وبین الظ�روف الس�یئة للس�كن مث�ل االكتظ�اظ وانع�دام الخصوص�یة بس�بب ص�غر تحتاج الى دراسة بما یس�اعد المؤسس�ات التعلیمی�ة مساحة المسكن ، فقد رأى الباحث ان ھذا العامل مشكلة حقیقیة واالسكانیة العمل معا لتحقیق االھداف المنشودة. اھمیة البحث تكمن اھمیة البحث في ما لھ من دور ف�ي التع�رف ال�ى جان�ب حس�اس ف�ي التعل�یم االبت�دائي اال وھ�و العالق�ة ب�ین علیھا من اھدار مادي وبش�ري وترب�وي ، ویمك�ن تحدی�د مساحة المسكن والمخرجات التعلیمیة للطفل وما یترتب -اھمیة البحث من خالل الجوانب التالیة : عدم وجود دراسات سابقة في ھذا المجال في العراق حسب علم الباحث -١ عمل المؤسسات االسكانیة والتعلیمیة معاعلى وضع السیاسات االسكانیة المناسبة التي من شأنھا االرتقاء -٢ بالتعلیم . سھام في اتخاذ القرار وتحدید االولویات المتعلقة برفع مستوى مخرجات العملیة التربویة في القطر.اال -٣ العمل على تقلیل االھدار الترب�وي الن�اتج ع�ن ت�دني المع�دالت الدراس�یة للتالمی�ذ بوض�ع خط�ط للمعالج�ة -٤ على ضوء نتائج البحث . متغیرات البحث ف التالمیذ حسب استقاللیة مدارس�ھم ال�ى مدرس�ة ذات دوام اح�ادي ، متغیر استقاللیة المدرسة : تم تصنی -١ مدرسة ذات دوام ثنائي ، ومدرسة ذات دوام ثالثي . /ف�رد) ال�ى ٢/ف�رد) : ت�م تص�نیف التالمی�ذ حس�ب (م٢متغیر المساحة االرضیة للفرد الواحد في المس�كن (م -٢ ) .٤٥-٤٠() ، ٣٥-٣٠) ، (٣٠-٢٥) ،(٢٥-٢٠) ، (٢٠-١٥) ، (١٥-١٠ستة فئات ( حدود البحث ٢٠١٥-٢٠١٤الحد الزماني : تم البحث في العام الدراسي الحد المكاني : اقتصر البحث على ثالتة مدارس ضمن الرقعة الجغرافیة لمحافظة كربالء المقدسة وكما یلي : مدرسة الروان كعینة للدوام االحادي -١ مدرسة مسلم بن عوسجة كعینة للدوام الثنائي -٢ اصحاب الحسین كعینة للدوام الثالثيمدرسة -٣ الح�د البش�ري : اقتص�رت الدراس�ة عل�ى عین�ة م�ن التالمی�ذ م�ن الم�دارس الم�ذكورة ف�ي الح�د المك�اني م�ن تالمی��ذ الصف السادس االبت�دائي م�ن الل�ذین أدوا امتح�ان البكالوری�ا وت�م تقس�یمھم حس�ب متغی�ر اس�تقاللیة المدرس�ة م�رة ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٤ /ف�رد) م�رة اخ�رى بع�د حس�اب مع�دالتھم ف�ي ذل�ك ٢للف�رد الواح�د ف�ي المس�كن (موحسب متغیر المساحة االرضیة االمتحان . تحدید المصطلحات معدل التلمیذ : معدل التلمیذ ال�ذي حص�ل علی�ھ ف�ي االمتح�ان النھ�ائي (البكالوری�ا) ویحس�ب مع�دل التلمی�ذ -١ حسب المعادلة التالیة : معدل التلمیذ = مجموع الدرجات التي حصل علیھا التلمیذ/ عدد الدروس /فرد) : المساحة المبنی�ة للط�ابق االرض�ي نس�بة ال�ى ع�دد ٢المساحة االرضیة للفرد الواحد في المسكن (م -٢ وتحسب االفراد في الوحدة السكنیة حسب المعلومات التي تم الحصول علیھا من البطاقة المدرسیة للتلمیذ حسب المعادلة التالیة : /فرد =المساحة المبنیة للطابق االرضي /عدد االفراد في الوحدة السكنیة٢م منھجیة البحث ھدفت الدراسة الى الكشف عن تأثیر عامل السكن ومساحة السكن على المخرجات التعلیمیة للتلمیذ وذلك باختیار ارس التي تم ذكرھا في الحد المكاني في ھذا البحث لغرض اجراء تلمیذ من تالمیذ المد ٧٢عینة عشوائیة حجمھا . )٢الجدول رقم (الدراسة من التالمیذ الذین شاركوا في االمتحان النھائي (البكالوریا) وكما مبین في )٢جدول رقم ( توزیع العینة اعتمادا على استقاللیة المدرسة المجموع ثالثي ثنائي احادي نوع الدوام ٧٢ ٢٥ ٣٢ ١٥ العینةحجم قام الباحث بحساب المعدالت العامة للتالمیذ من الدرجات التي تم الحصول علیھا م�ن الس�جالت المدرس�یة بغ�ض . )١الملحق رقم ( النظر عن درجة النجاح لكل مادة ثم قام بعرضھا وتبویبھا كما في .) ٣في الجدول رقم (تلمیذ وكما مبین /فرد) لكل ٢تم توزیع نفس العینة الى ستة فئات اعتمادا على (م )٣جدول رقم ( /فرد)٢توزیع العینة اعتمادا على (م المجموع ٤٥-٤٠ ٣٥-٣٠ ٣٠-٢٥ ٢٥-٢٠ ٢٠-١٥ ١٥-١٠ /فرد)٢(م حج�������������م العینة ٧٢ ٥ ٦ ١٥ ٢٤ ١٥ ٧ ت�م الحص�ول عل�ى المس��احة المبنی�ة للط�ابق االرض��ي و ع�دد االف�راد ف��ي الوح�دة الس�كنیة لك��ل تلمی�ذ م�ن البیان��ات . )٢الملحق رقم (الواردة في البطاقة المدرسیة للتلمیذ وقد قام الباحث بعرضھا وتبویبھا في احص�ائیا باس�تخدام االحص�اء الوص�في ) ٢) والملح�ق (١تم تحلیل البیانات التي تم جمعھ�ا وتبویبھ�ا ف�ي الملح�ق ( ) anovaواالستداللي بواس�طة حس�اب االوس�اط الحس�ابیة واالنحراف�ات المعیاری�ة وتحلی�ل التب�این االح�ادي ( -لمعدالت التالمیذ العامة ، حیث ان محور البحث قد تركز حول االجابة على السؤالین التالیین : ت التالمیذ اعتمادا على استقاللیة المدرسة .ھل یوجد فروقات ذات داللة احصائیة بین معدال -١ ھل یوجد فروقات ذات داللة احصائیة بین معدالت التالمیذ اعتمادا على مساحة المسكن -٢ analysis of varianceتحلیل التباین ھ�و اح��د االدوات االحص��ائیة المھم��ة والت��ي تعن�ى بدراس��ة العالق��ة ب��ین متغی��ر كم�ي ت��ابع م��ع متغی��ر اخ��ر او ع��دة متغیرات مستقلة والتي عادة ما تكون وصفیة ویھتم تحلیل التباین ف�ي عملی�ة البح�ث او تحدی�د مص�ادر االخ�تالف ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٥ تابع�ة والمتغی�رات المس�تقلة . ویت�درج تحلی�ل بین المتوس�طات وال یھ�تم ف�ي تحدی�د ن�وع العالق�ة ب�ین المتغی�رات ال التباین من تحلیل التباین بعامل واحد الى تحلیل التباین بعاملین ثم تحلی�ل التب�این للبیان�ات المتك�ررة ث�م ال�ى ان�واع ).٢٠٠٧،القصاص) (anovaاخرى مختلفة . وعادة ما یختصر اسم ھذه الطریقة ( نیف المشاھدات الى عدد م�ن المجموع�ات عل�ى اس�اس خاص�یة واح�دة وتحلیل التباین االحادي ھو عبارة عن تص ویكون ذلك بإخضاع عدة تجارب لعدد من المعامالت التي تمث�ل مس�تویات الخاص�یة الواح�دة واختب�ار ت�أثیر ھ�ذه ).٢٠٠٧،القصاص المعامالت على المشاھدات التي نحصل علیھا ( الحسابات ومناقشة النتائج االجابة على السؤال االول وھو ھل یوجد فروقات ذات داللة احصائیة بین معدالت التالمیcذ اعتمcادا علcى -اوال : استقاللیة المدرسة . لالجابة عن ھذا السؤال فقد قام الباحث باختبار الفرضیة الصفریة : h0 استقاللیة المدرسة= ال توجد فروقات ذات داللة احصائیة بین معدالت التالمیذ اعتمادا على مقابل الفرضیة البدیلة : h1یوجد فروقات ذات داللة احصائیة بین معدالت التالمیذ اعتمادا على استقاللیة المدرسة = عبر حساب االوساط الحسابیة لمعدالت التالمیذ عینة البحث حسب المدارس المذكورة ف�ي الح�د المك�اني م�ن ھ�ذا ):٢٠٠٨،(طبیةالبحث باستخدام المعادلة التالیة ! "= 1 # !"#"$% ��������������������������������(1) عدد التالمیذ n معدل التلمیذ و xi الوسط الحسابي و x̅حیث : وكذلك حساب االنحرافات المعیاریة والتباینات لمعدالت التالمیذ باستخدام المعادالت التالیة : & '=*1+ (!" # "$% ,!-).�����������������//(2) &. '= 1+ (!" # "$% ,!-).����������������/ /��(3) عدد التالمیذ .n معدل التلمیذ و xi الوسط الحسابي و x̅التباین و .&االنحراف المعیاري و σحیث : . )٤الجدول رقم (وعلیھ فان التحلیل االحصائي لعینة البحث اعتمادا على استقاللیة المدرسة ھي كما مبین في )٤رقم (جدول التحلیل االحصائي اعتمادا على استقاللیة المدرسة االنحoooooooooooooooooooooراف الوسط الحسابي حجم العینة نوع الدوام المعیاري التباین ٢٥.٤٤ ٥.٠٤ ٦٦.٤ ١٥ احادي ١٤٩.٧١ ١٢.٢٤ ٦٣.٣١ ٣٢ ثنائي ١٨٨.٥٢ ١٣.٧٣ ٥٩.٧٢ ٢٥ ثالثي ١٤٣.٤ ١١.٩٨ ٦٢.٧١ ٧٢ كلي ) االحoادي لمعرفoة داللoة الفoرق بoین متوسoطات التالمیoذ اعتمoادا علoى anova(بعد ذلك اجري تحلیل التبoاین بعooد ترتیooب البیانooات علooى شooكل مصooفوفة باسooتخدام المعooادالت التالیooة ٠.٠٥اسooتقاللیة المدرسooة بمسooتوى داللooة )leblanc,2004:( ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٦ 004= (5"6,57//#6$% 8 "$% ).�����������������//(9) ! = "(#$%. & #$.. ' %)* +, � � � � � � � � � � � � . � � � � � � � (5+ = " "(#%/ & #$%. 0 /)* ' %)* +, � � � � � � � � � � � � � � . . � � . . (6+ مجم��وع المربع��ات لمع��دالت الص��فوف اي مجم��وع المربع��ات ssrمجم��وع المربع��ات الكل��ي و sstحی��ث : .%$#ع�دالت التالمی�ذ و الوس�ط الحس�ابي ل�م ..$#معدل التلمیذ و /%#مجموع المربعات للخطأ و sseللمعامالت و الوسط الحسابي للصفوف . ):leblanc,2004كما تم حساب درجات الحریة باستخدام المعادالت التالیة ( dfالمعامالت=k-1……………………………….…………….…..… (7) dfالخطأ=k(n-1)………………………………………………....…. (8) dfالمجموع=dfالمعامالت+df(9) …………...………………………الخطأ عدد االعمدة . n عدد الصفوف و kدرجة الحریة و dfحیث ) بمس��توى دالل��ة ٣.١٤الجدولی��ة الت��ي تس��اوي ( f) وھ��ي اص��غر م��ن ١.٥٨المحس��وبة تس��اوي ( fتب��ین ان قیم��ة . )٥الجدول رقم () وكما مبین في ٠.٠٥( )٥جدول رقم ( تحلیل التباین االحادي اعتمادا على استقاللیة المدرسة مص������������������در التغییر مجم������������������وع المربعات درج����������������ات الحریة مع�����������������������دل المربعات fقیم��������������ة المحسوبة fقیم���������������������ة الجدولیة ٣.١٤ ١.٥٨ ٢٢٦.٥١٨٤ ٢ ٤٥٣.٠٣٦٧ المعامالت ١٤٣.٢٦٨٣ ٦٩ ٩٨٨٥.٥١٥ الخطأ ١٤٥.٦١٣٤ ٧١ ١٠٣٣٨.٥٥ الكلي ونعتبر ان لیس ھناك فروقات ذات داللة احصائیة ب�ین متوس�طات التالمی�ذ اعتم�ادا عل�ى اس�تقاللیة h0لذلك نقبل ). وھذا مؤش�ر خطی�ر ی�دل عل�ى ع�دم ت�أثیر اس�تقاللیة المدرس�ة عل�ى المخرج�ات ٠.٠٥المدرسة بمستوى داللة ( ام الدراس�ي ال�ذي ت�م فی�ھ اج�راء التعلیمیة للتالمیذ خصوصا اذا ما اخذنا بنظر االعتبار تدني نسب النج�اح ف�ي الع� البحث . لذا یقترح الباحث ان تكون ھذه النتیجة مجاال الجراء البحوث المستقبلیة للوقوع على األسباب ومعالجتھا . ثانیا/ االجابة على السؤال الثاني وھو ھل یوجد فروقات ذات داللة احصائیة بین معدالت التالمی"ذ اعتم"ادا عل"ى مساحة المسكن . لالجابة عن ھذا السؤال فقد قام الباحث باختبار الفرضیة الصفریة : h0ال توجد فروقات ذات داللة احصائیة بین معدالت التالمیذ اعتمادا على مساحة المسكن = مقابل الفرضیة البدیلة : h1یوجد فروقات ذات داللة احصائیة بین معدالت التالمیذ اعتمادا على مساحة المسكن = االوساط الحسابیة لمعدالت التالمی�ذ عین�ة البح�ث حس�ب متغی�ر المس�احة االرض�یة للف�رد الواح�د ف�ي عبر حساب اعتم�ادا عل�ى ذل�ك المتغی�ر .وك�ذلك حس�اب االوس�اط /فرد) بع�د ان ت�م توزی�ع التالمی�ذ ال�ى س�تة قئ�ات٢المسكن (م ) . ٣) و(٢) و(١الحسابیة واالنحرافات المعیاریة والتباینات لمعدالت التالمیذ باستعمال المعادالت ( ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٧ وعلی��ھ ف��ان التحلی��ل االحص��ائي لعین��ة البح��ث اعتم��ادا عل��ى متغی��ر المس��احة االرض��یة للف��رد الواح��د ف��ي المس��كن . )٦الجدول رقم (في /فرد) ھي كما مبین٢(م )٦جدول رقم ( /فرد)٢التحلیل االحصائي اعتمادا على المساحة االرضیة للفرد الواحد في المسكن (م االنح���������������������راف الوسط الحسابي حجم العینة /فرد)٢(م المعیاري التباین ٨٥.٢٧ ٩.٢٣ ٥٧.٨٦ ٧ ١٥-١٠ ١٠٠.٤٦ ١٠.٠٢ ٥٦.٩٣ ١٥ ٢٠-١٥ ١٣٩.٩٢ ١١.٨٣ ٦٢ ٢٤ ٢٥-٢٠ ٤٦.٣٨ ٦.٨١ ٦١.٨٧ ١٥ ٣٠-٢٥ ١٤٠.٨٩ ١١.٨٧ ٧٨.٣٣ ٦ ٣٥-٣٠ ١٠٦.٤ ١٠.٣٢ ٧٤ ٥ ٤٥-٤٠ ١٤٣.٤ ١١.٩٨ ٦٢.٧١ ٧٢ الكلي ) االح�ادي لمعرف�ة دالل�ة الف�رق ب�ین متوس�طات التالمی�ذ اعتم�ادا عل�ى anovaبعد ذلك اجري تحلیل التب�این ( بعد ترتیب البیانات على شكل مصفوفة ٠.٠٥داللة /فرد)بمستوى٢المساحة االرضیة للفرد الواحد في المسكن (م ) .٦( ) ،٥) ، (٤باستخدام المعادالت ( ) .٩) ، (٨) ، (٧كذلك تم حساب درجات الحریة باستخدام المعادالت ( ) بمس��توى دالل��ة ٢.٣٦٩الجدولی��ة الت��ي تس��اوي ( f) وھ��ي اكب��ر م��ن ٥.٦٥المحس��وبة تس��اوي ( fتب��ین ان قیم��ة الج"دول رق"م اي ان ھناك فروقات معنوی�ة واض�حة وكبی�رة وكم�ا مب�ین ف�ي h1 ونقبل h0ض ) لذلك نرف٠.٠٥( )٧( . )٧جدول رقم ( /فرد)٢تحلیل التباین االحادي اعتمادا على المساحة االرضیة للفرد الواحد في المسكن (م مص������������������در التغییر مجم������������������وع المربعات درج����������������ات الحریة مع�����������������������دل المربعات fقیم��������������ة المحسوبة fقیم���������������������ة الجدولیة ٢.٣٦٩ ٥.٦٥ ٦٤٤.٩٢ ٥ ٣٢٢٤.٥٨ المعامالت ١١٤.١٦ ٦٦ ٧٥٣٤.٨٦ الخطأ ١٥١.٥٤ ٧١ ١٠٧٥٩.٤٤ الكلي یتض��ح م��ن الج��دول اع��اله وج��ود فروق��ات ذات دالل��ة احص��ائیة ب��ین متوس��طات التالمی��ذ اعتم��ادا عل��ى المس��احة ) . اي ان لعامل السكن ومساحة المس�كن ت�أثیر ٠.٠٥(/فرد) بمستوى داللة ٢االرضیة للفرد الواحد في المسكن (م ) وج��د ان المتوس��ط ٦عل�ى المخرج��ات التعلیمی�ة والمس��توى الدراس�ي للتلمی��ذ وك�ذلك م��ن مالحظ�ة الج��دول رق�م ( ٥٧.٨٦/ف���رد) ھم���ا االوط���أ (٢) (م٢٠-١٥/ف���رد) والفئ���ة (٢) (م١٥-١٠الحس���ابي لمع���دالت التالمی���ذ للفئت���ین ( ٧٨.٣٣/فرد) لھما اعلى المتوسطات (٢) (م٤٥-٤٠/فرد) و(٢) (م٣٥-٣٠ان الفئتین () على التوالي ، و٥٦.٩٣و ٦٢/فرد)كان���ت متوس���طاتھا الحس���ابیة (٢) (م٣٠-٢٥/ف���رد)و(٢) (م٢٥-٢٠) عل���ى الت���والي بینم���ا الفئ���ات (٧٤و ب��ر ) عل��ى الت��والي اي ان��ھ یمك��ن الق��ول بتحس��ن المخرج��ات التعلیمی��ة والمس��توى الدراس��ي للتلمی��ذ م��ع ك٦١.٨٧و /فرد) للتلمیذ .٢المساحة االرضیة للفرد الواحد في المسكن (م االستنتاجات كانت النتائج التي أظھرتھا ھذه الدراسة ھي : ھناك تأثیر لعامل السكن ومساحة المسكن على المستوى الدراسي للتلمیذ . -١ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٨ مساحة المسكن كلما كبر مساحة المسكن لھ تأثیر ایجابي على المستوى الدراسي للتلمیذ ،كلما كبرت -٢ تحسن المستوى الدراسي للتلمیذ . عدم وجود تأثیر لعامل استقاللیة المدرسة على المستوى الدراسي للتلمیذ حسب نتائج البحث ، وھذا -٣ یعني تراجع دور المدرسة في رفع المستوى الدراسي للتلمیذ باالضافة الى مشكلة االزدواج المدرسي ة الى التخلص منھ لرفع المستوى الدراسي للتلمیذ من خالل بناء المزید من الذي تسعى الجھات المسؤول المدارس لفك ھذا االزدواج . دور المسكن اكبر من دور المدرسة في رفع المستوى الدراسي للتلمیذ . -٤ المصادر 1. beatty. a,” student mobility: exploring the impact of frequent moves on achievement: summary of a workshop”, national research council and institute of medicine. washington, dc: the national academies press. 2010. 2. braconi, f,” housing and schooling. the urban prospect”. new york: citizen’s and planning council, 7(2): 1-4,2001. 3. centers for disease control and prevention (cdc). preventing lead poisoning in young children. atlanta, ga: us department of health and human services, cdc, national center for environmental health,2011. 4. cohen, rebecca and keith wardrip,” should i stay or should i go? exploring the effects of housing instability and mobility on children.”, washington, dc: center for housing policy,2011. 5. evans, g., s. saegert, and r. harris,” residential density and psychological health among children in low-income families”, environment and behavior. 33(2): 165-180,2001. 6. leblanc, d.c., statistics: concept and applications, jones & bartlett publishers, boston,ma, 2004. 7. : lubell, jeffrey and maya brennan,” the positive impacts of affordable housing on education: a research summary.”, washington, dc: center for housing policy and enterprise community partners,2007. 8. padco/un-habitat,household survey, 2006. 9. republic of iraq ministry of construction & housing,” iraq housing market study”, main report,2006. 10. scanlon, e. and k. devine,” residential mobility and youth well-being: research, policy, and practice issues” . journal of sociology and social welfare 28(1): 119-138,2001. 11. wong, john h and others. 2009.” mckinneyvento homeless assistance act subtitle beducation for homeless children and youths program: turning good law into effective education”, georgetown journal on poverty law and policy 16(1): 53-115,2009. .٢٠٠٨د.احمد عبد السمیع طبیھ،"مباديء االحصاء" ، دار الحریة، .١٢ ٢٠١٤اء، التقریر السنوي ، جمھوریة العراق/ وزارة التخطیط / الجھاز المركزي لالحص .١٣ .٢٠٠٧د.مھدي محمد القصاص،" مباديء االحصاء والقیاس االجتماعي"، دار المعرفھ الجامعیة، .١٤ ١ملحق رقم توزیع العینة اعتمادا على استقاللیة المدرسة اوال: الدوام االحادي م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ٢٣.٠٨ ٣٠٠ ١٣ ٦٦ ١ ٤٠ ٢٠٠ ٥ ٥٨ ٢ ٢٢.٧٢ ٢٥٠ ١١ ٧٦ ٣ ٣٣.٣٣ ٢٠٠ ٦ ٧١ ٤ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٣٩ ٢٨.٥٧ ٢٠٠ ٧ ٦٢ ٥ ٢٦ ٢٦٠ ١٠ ٦٦ ٦ ٢٧ ٢٧٠ ١٠ ٦٢ ٧ ٢٧.٥ ٢٢٠ ٨ ٦٣ ٨ ٢٨.٥٧ ٢٠٠ ٧ ٦٨ ٩ ٣٠ ٣٠٠ ١٠ ٧٢ ١٠ ٣١.٢٥ ٢٥٠ ٨ ٦١ ١١ ٢٠.٨٣ ٢٥٠ ١٢ ٦٩ ١٢ ٢٤.٤٤ ٢٢٠ ٩ ٦٢ ١٣ ٢١.٤٣ ٣٠٠ ١٤ ٧٤ ١٤ ٢٨.٥٧ ٢٠٠ ٧ ٦٦ ١٥ الدوام الثنائيثانیا : م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ١٤.٢٩ ١٠٠ ٧ ٦١ ١ ١٦.٦٧ ١٠٠ ٦ ٤٨ ٢ ٢٥ ١٥٠ ٦ ٦٦ ٣ ٤١.٦٧ ٢٥٠ ٦ ٧٧ ٤ ٢١.٤٣ ١٥٠ ٧ ٦٥ ٥ ١٣.٦٤ ١٥٠ ١١ ٦٣ ٦ ٢٠ ١٨٠ ٩ ٦٩ ٧ ٢٢.٢٢ ٢٠٠ ٩ ٥٩ ٨ ٤٠ ٢٠٠ ٥ ٨١ ٩ ٢٢.٢٢ ٢٠٠ ٩ ٧٣ ١٠ ١٦.٦٧ ١٥٠ ٩ ٤٩ ١١ ١٤.٢٩ ١٠٠ ٧ ٥٥ ١٢ ١٨.٧٥ ١٥٠ ٨ ٧٥ ١٣ ٢٢.٢٢ ٢٠٠ ٩ ٣٤ ١٤ ٢٥ ١٥٠ ٦ ٦٥ ١٥ ١٦.٦٧ ١٠٠ ٦ ٣٦ ١٦ ١٨.١٨ ٢٠٠ ١١ ٦٣ ١٧ ٤١.٦٧ ٢٥٠ ٦ ٦٧ ١٨ ٢٥ ١٥٠ ٦ ٦٢ ١٩ ٢٥ ١٥٠ ٦ ٦٢ ٢٠ ١٤.٢٩ ٢٠٠ ١٤ ٧٢ ٢١ ٢٠ ٢٠٠ ١٠ ٧٥ ٢٢ ٢٥ ٢٠٠ ٨ ٦٩ ٢٣ ١٦.٦٧ ١٠٠ ٦ ٦٧ ٢٤ ٢٧.٧٨ ٢٥٠ ٩ ٤٤ ٢٥ ٤٠ ٢٠٠ ٥ ٨٧ ٢٦ ١٩.٢٣ ٢٥٠ ١٣ ٦٩ ٢٧ ٢١.٤٣ ١٥٠ ٧ ٧٣ ٢٨ ٢٥ ٢٠٠ ٨ ٤٧ ٢٩ ٢١.٤٣ ١٥٠ ٧ ٧٧ ٣٠ ٢٥ ٢٥٠ ١٠ ٦٢ ٣١ ٢٠ ١٠٠ ٥ ٥٤ ٣٢ ثالثا : الدوام الثالثي ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٤٠ م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ١٤.٢٩ ١٠٠ ٧ ٤٠ ١ ١٢.٥ ١٠٠ ٨ ٥٣ ٢ ٢١.٤٣ ١٥٠ ٧ ٦٧ ٣ ٢١.٤٣ ١٥٠ ٧ ٦٤ ٤ ١٧.١٤ ١٢٠ ٧ ٥٦ ٥ ٢٠ ٢٠٠ ١٠ ٤٥ ٦ ٣٣.٣٣ ٢٠٠ ٦ ٩٨ ٧ ١٦.٦٧ ١٥٠ ٩ ٥٠ ٨ ١٦.٦٧ ١٠٠ ٦ ٥٤ ٩ ٢٠ ٢٠٠ ١٠ ٥١ ١٠ ١٩.٢٣ ٢٥٠ ١٣ ٥١ ١١ ٢١.٤٣ ١٥٠ ٧ ٦٣ ١٢ ٢٠ ١٠٠ ٥ ٤٧ ١٣ ١٦.٦٧ ١٠٠ ٦ ٥٠ ١٤ ١٥.٦٣ ١٢٥ ٨ ٦٩ ١٥ ٢٠ ١٠٠ ٥ ٥٢ ١٦ ٣٣.٣٣ ١٠٠ ٣ ٨٤ ١٧ ٢٠ ١٢٠ ٦ ٣٨ ١٨ ١٨.٧٥ ١٥٠ ٨ ٥٥ ١٩ ٢٥ ٢٠٠ ٨ ٦٤ ٢٠ ٣٠ ١٥٠ ٥ ٨٤ ٢١ ٢٠ ١٠٠ ٥ ٦٨ ٢٢ ٢٠ ١٠٠ ٥ ٦٧ ٢٣ ١٦.٦٧ ١٠٠ ٦ ٦٢ ٢٤ ١٤.٢٩ ١٠٠ ٧ ٦١ ٢٥ ٢الملحق رقم توزیع العینة اعتمادا على (م ٢ /فرد) م اوال : ٢ ١٥-١٠= /فرد م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ١٢.٥ ١٠٠ ٨ ٥٣ ١ ١٣.٦٤ ١٥٠ ١١ ٦٣ ٢ ١٤.٢٩ ١٠٠ ٧ ٦١ ٣ ١٤.٢٩ ١٠٠ ٧ ٥٥ ٤ ١٤.٢٩ ٢٠٠ ١٤ ٧٢ ٥ ١٤.٢٩ ١٠٠ ٧ ٤٠ ٦ ١٤.٢٩ ١٠٠ ٧ ٦١ ٧ م ثانیا : ٢ ٢٠-١٥= /فرد م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ١٥.٦٣ ١٢٥ ٨ ٦٩ ١ ١٦.٦٧ ١٠٠ ٦ ٤٨ ٢ ١٦.٦٧ ١٥٠ ٩ ٤٩ ٣ ١٦.٦٧ ١٠٠ ٦ ٣٦ ٤ ١٦.٦٧ ١٠٠ ٦ ٦٧ ٥ ١٦.٦٧ ١٥٠ ٩ ٥٠ ٦ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٤١ ١٦.٦٧ ١٠٠ ٦ ٥٤ ٧ ١٦.٦٧ ١٠٠ ٦ ٥٠ ٨ ١٦.٦٧ ١٠٠ ٦ ٦٢ ٩ ١٧.١٤ ١٢٠ ٧ ٥٦ ١٠ ١٨.١٨ ٢٠٠ ١١ ٦٣ ١١ ١٨.٧٥ ١٥٠ ٨ ٧٥ ١٢ ١٨.٧٥ ١٥٠ ٨ ٥٥ ١٣ ١٩.٢٣ ٢٥٠ ١٣ ٦٩ ١٤ ١٩.٢٣ ٢٥٠ ١٣ ٥١ ١٥ م ثالثا : ٢ ٢٥-٢٠= /فرد م المسكنمساحة عددافراد االسرة المعدل ت ٢ /فرد ٢٠ ١٨٠ ٩ ٦٩ ١ ٢٠ ٢٠٠ ١٠ ٧٥ ٢ ٢٠ ١٠٠ ٥ ٥٤ ٣ ٢٠ ٢٠٠ ١٠ ٤٥ ٤ ٢٠ ٢٠٠ ١٠ ٥١ ٥ ٢٠ ١٠٠ ٥ ٤٧ ٦ ٢٠ ١٠٠ ٥ ٥٢ ٧ ٢٠ ١٢٠ ٦ ٣٨ ٨ ٢٠ ١٠٠ ٥ ٦٨ ٩ ٢٠ ١٠٠ ٥ ٦٧ ١٠ ٢٠.٨٣ ٢٥٠ ١٢ ٦٩ ١١ ٢١.٤٣ ٣٠٠ ١٤ ٧٤ ١٢ ٢١.٤٣ ١٥٠ ٧ ٦٥ ١٣ ٢١.٤٣ ١٥٠ ٧ ٧٣ ١٤ ٢١.٤٣ ١٥٠ ٧ ٧٧ ١٥ ٢١.٤٣ ١٥٠ ٧ ٦٧ ١٦ ٢١.٤٣ ١٥٠ ٧ ٦٤ ١٧ ٢١.٤٣ ١٥٠ ٧ ٦٣ ١٨ ٢٢.٢٢ ٢٠٠ ٩ ٥٩ ١٩ ٢٢.٢٢ ٢٠٠ ٩ ٧٣ ٢٠ ٢٢.٢٢ ٢٠٠ ٩ ٣٤ ٢١ ٢٢.٧٢ ٢٥٠ ١١ ٧٦ ٢٢ ٢٣.٠٨ ٣٠٠ ١٣ ٦٦ ٢٣ ٢٤.٤٤ ٢٢٠ ٩ ٦٢ ٢٤ م رابعا : ٢ ٣٠-٢٥= /فرد م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ٢٥ ١٥٠ ٦ ٦٦ ١ ٢٥ ١٥٠ ٦ ٦٥ ٢ ٢٥ ١٥٠ ٦ ٦٢ ٣ ٢٥ ١٥٠ ٦ ٦٢ ٤ ٢٥ ٢٠٠ ٨ ٦٩ ٥ ٢٥ ٢٠٠ ٨ ٤٧ ٦ ٢٥ ٢٥٠ ١٠ ٦٢ ٧ ٢٥ ٢٠٠ ٨ ٦٤ ٨ ٢٦ ٢٦٠ ١٠ ٦٦ ٩ ٢٠١٧ ١العدد ١٠مجلة القادسیة للعلوم الھندسیة المجلد ٤٢ ٢٧ ٢٧٠ ١٠ ٦٢ ١٠ ٢٧.٥ ٢٢٠ ٨ ٦٣ ١١ ٢٧.٧٨ ٢٥٠ ٩ ٤٤ ١٢ ٢٨.٥٧ ٢٠٠ ٧ ٦٢ ١٣ ٢٨.٥٧ ٢٠٠ ٧ ٦٨ ١٤ ٢٨.٥٧ ٢٠٠ ٧ ٦٦ ١٥ م خامسا : ٢ ٣٥-٣٠= /فرد م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ٣٠ ٣٠٠ ١٠ ٧٢ ١ ٣٠ ١٥٠ ٥ ٨٤ ٢ ٣١.٢٥ ٢٥٠ ٨ ٦١ ٣ ٣٣.٣٣ ٢٠٠ ٦ ٧١ ٤ ٣٣.٣٣ ٢٠٠ ٦ ٩٨ ٥ ٣٣.٣٣ ١٠٠ ٣ ٨٤ ٦ م سادسا : ٢ ٤٥-٤٠= /فرد م مساحة المسكن عددافراد االسرة المعدل ت ٢ /فرد ٤٠ ٢٠٠ ٥ ٥٨ ١ ٤٠ ٢٠٠ ٥ ٨١ ٢ ٤٠ ٢٠٠ ٥ ٨٧ ٣ ٤١.٦٧ ٢٥٠ ٦ ٧٧ ٤ ٤١.٦٧ ٢٥٠ ٦ ٦٧ ٥ ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١ شكل السطح الماص على الحمل الحراري القسري لمجمعات هوائية شمسية تأثير عامر جميل شريف.م.م قسم الهندسة الميكانيكية/كلية الهندسة/جامعة االنبار الخالصة -sinusoidal waveالمتموج ,v-corrugated المتعرج , flatالمستوي (تضمن البحث دراسة تاثير شكل اللوح الماص corrugated , والمستطيلrectangular-corrugated ( مائـل متر٠,١ه وعرضه واحد متر وسمكه طول لمجمع هوائي شمسي عنـد فـيض حـراري شمـسي ثابـت معامل االحتكـاك الـسطحي القسري الحمل على معامل انتقال الحرارة ب )30o(عن االفق )530w/m2 ( عدد رينولدولمدى) 5000≤re≤8000(. معادلة االستمراريه (تم حل المعادالت التفاضلية الحاكمة حيث , في الدراسة الحالية)fluent(البرنامج العدديم اأستخدم ت مع األخذ بنظر االعتبار أن الجريان مضطرب ثنائي البعد للحالة ) finite volume(بطريقة الحجوم المحددة) الزخم والطاقة, .المستقرة وافضل معامل انتقـال للحـرارة ) 13.65oc( كانت فرق في درجة حرارة الهواء الخارج والداخل ان اعلى أظهرت النتائج عن المجمع المـستوي ) %63( وبنسبة تحسن )60oزاوية التعرج ()v-corrugated( بالحمل القسري يحدث عند المجمع المتعرج )flat plate( رينولد عدد عند)(ر لمعامل االحتكاك السطحي مقداأظهرت النتائج أن اعلى وكما,)٨٠٠٠cf( يحدث فـي المجمـع ).٨٠٠٠(رينولد عدد عند )0.22 (ت قيمتهغحيث بل) v-corrugated (المتعرج .الحمل القسري,المجمعات الهوائية الشمسية,ةح الماصو السط:الكلمات الرئيسية effect of absorber surface shape on the forced thermal convection of solar air collectors asst. lec. amer jameel shareef al-anbar university-engineering college mechanical engineering dep. in this research a study effect of absorber surface shape for solar air collector (flat v-corrugated ,sinusoidal wave-corrugated ,rectangular-corrugated)(1 × 1 × 0.1m) titled to the horizontal by an angle(30o) on forced heat transfer and skin friction coefficient by fluent numerical program at constant solar heat flax (530w/m2) with reynold’s number (5000≤re≤8000). ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٢ the government equation (mass, momentum and energy) are using finite volume by (fluent 6.3) software for considering steady state, two dimensional and turbulent flow. the results show that the different between inlet and outlet air temperature is(13.65 oc) and best heat transfer coefficient enhancement is(63%) for (v-corrugated plate) compared with the flat plate at (re=8000), also the results show that the maximum skin friction coefficient is occured at (v-corrugated) cf=0.22 at (re=8000). الرموز المقدمة اذ توجد عدة , يحتاجها العالميتعتبر الطاقة الشمسية واحدة من اهم مصادر الطاقة البديلة والمتجددة الت السطح الماص: اربع اجزاء رئيسية تتكون من مجمعات الهواء الشمسية والتي تغالل هذه الطاقة منها طرق الس )absorber plate (السطح والمغطىفقدها الى الهواء المار على ي ومن ثم الذي يمتص الطاقة الساقطة عليه والتي تعمل على يسمح بنفوذ االشعاع الشمسي خالله الذي )glass cover(بطبقة او اكثر من زجاج النوافذ ارة داخل المجرى الهوائيتقليل الخسائر الحرارية بالحمل الى المحيط الخارجي وبالتالي حبس الحر )air duct ( ما بين الصفيحة الماصة والزجاج الذي يسمح بمرور الهواء فوق او تحت الصفيحة الماصة الوحدات المعنى الرمز الوحدات المعنى الرمز u,v االفقية والعموديةالسرعة m/s µeff اللزوجة المؤثرة kg/s.m ρ كثافة الهواء kg/m3 preff رقم براندتل المضطرب µ اللزوجة الديناميكية kg/s.m σk عدد برانتل المضطرب للمودیل k t درجة الحرارة oc σε رانتل المضطرب للمودیل عدد ب ε β 1 معامل التمدد الحجمي/k µt لزوجة االضطراب المائع kg/s.m α االنتشاریة الحراریة m2/s cμ,c1ε,cε الطاقة الحركیة المضطربة لوحدة الكتلة m2/s٢/kg g حد التولید re عدد رينولد β degree nu زاویة المیل عدد نسلتمعدل dh القطر الهايدروليكي m p الضغط pa ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٣ يتم عزل المجمع من الخلف والجوانب بعازل حراري ومن ثم , لغرض امتصاص الحرارة الالزمة للتسخين .[1]مناسب 1967([2] (gupta and garg)(قامأذ ,لتحسين ادائهاالنظرية والعملية من الدراسات هنالك العديد يب ورخيصة الثمن أثنان منها ذا بدراسة عملية لمعرفة اداء وخواص أربع سخانات شمسية هوائية بسيطة الترك ) mesh(واألثنان اآلخران ذات صفيحة امتصاص شبكية) v( لوحة امتصاص متعرجة على شكل حرفت وتبين من الدراسة ان السخانات ذوات اللوح الماص المتعرج يمكن ان . جموضوعة فوق اللوح الماص المتعر هي عليها أعلى من درجة حرارة المحيط الخارجي وان الكفاءة التي يمكن الحصول 30ocتسخن الهواء الى أعلى من درجة حرارة 20oc ح الماص الشبكية تجهز هواء ساخن بمعدل او ،وان السخانات ذوات االل60% بدراسة خصائص السخان الشمسي ) 1892(قامت الباحثة نجيبة الحمداني ).%50( الخارجي وان كفاءتهاالمحيط وكان جريان الهواء تحت اللوح ) v(شكل حرف الهوائي في العراق باستخدام لوحة امتصاص متعرجة على )goel et.al.)(1987( الباحثون اجرى.%60مقدارهاخدام خزان حراري وحصلت على كفاءة الماص وباست لوحة امتصاص لوحة امتصاص مسطحة و، وهي ثالثة انواع من السخانات الشمسيةدراسة األداء الحراري ل أن أعلى كفاءة وتبين من الدراسة . )v(والثالثة متعرجة بشكل حرف )sine wave(متعرجة بشكل موجة جيبية قدم الباحث .).v(كل حرف تم الحصول عليها من السخان الشمسي ذي اللوح الماص المتعرج على ش )hollands( ة لمجمع نوع المتعرجيدراسة تجريب )v ( واستنتج كلما زاد التعرج ازدادت كمية امتصاص -v( قدم دراسة مجمع نوع) sayigh,1977(اما الباحث . االشعاع الشمسي الساقطة على اللوح الماص corrugate (عن زاوية التعرج )55o-60o(,لمجمع المعرض لالشعاع تزداد بمعدل توصل الى ان مساحة ا joudi(الباحثانكما قاما .الزوايا الماص الى الهواءعند هذه الضعف وكذلك يزداد معدل انتقال الحرارة من اللوح and mohamed نوع شمسيالداءالحراري لمجمع هوائي ل بدراسة تجريبية)v-corrugate( لزاوية التعرج )60o( وان الكفاءة شتاءا افضل , ع تزداد مع زيادة معدل تدفق الهواءجممتوصال الى ان كفاءة الو ذو لوح بدراسة عملية لمجمع هوائي شمسي ) ٢٠٠٦,جنان مهدي( الباحثة قامت,منها صيفا)%6(بمقدار امتصاص مسطح يحتوي على حواجز عرضية ألعاقة مرور الهواء الداخل الى المجمع الشمسي، وتكون هذه تم التوصل , لصفيحة األمتصاص وموزعة بشكل منتظم على طول اللوحمن الجهة العليا الشكل والعوارض مثلثة .بسبب زيادة اضطراب في جريان الهواءالى ان كفاءة المجمع تزداد بوجود هذه العوارض بثبوت الفيض المائلة الى دراسة تأثير شكل السطح الماص لمجمعات الهواء الشمسيالحالي يهدف البحث لغرض محاكاة البحوث السابقة فقط وليس له تأثير على معامل (عن االفق )30o(زاوية مسلط ويميل بالحراري ال تقال الحرارة بالحمل القسري ان وايجاد معامل ومعامل االحتكاك السطحي على الحمل الحراري )أنتقال الحرارة .لهذه االسطح ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٤ المحاكاة العددية , المجمعات الهوائية الشمسيةيناميكية المائع وانتقال الحرارة داخلإلظهار د) fluent(استخدم البرنامج كما, القسري المعادالت الحاكمة للحملحلل) finite volume(يعتمد هذا البرنامج على طريقة الحجوم المحددة يات اآلتية الفرضأعتماد تم .ةوالتوليد الشبكي الخاص بالمسألالهندسي لبناء النموذج (gambit)برنامج استخدم :لحل المسألة وهي .جريان مضطرب -٤ .مستقرةالحالة ال -١ .مائع غير انضغاطي -٥ .الجريان ثنائي البعد -٢ .ثبوت الفيض الحراري -٦ .المائع خاضع لقانون نيوتن للزوجة -٣ هواء ثابتة ماعدا الكثافةأي جميع خواص ال) boussinesq( تطبيق تقريب-٧ يتم تحويل معادالت التفاضلية, المجمعات الهوائية الشمسيةداخل القسريلدراسة ظاهرة الحمل ) حفظ الكتلة( والتي تمثل معادالت االستمرارية القسريظاهرة الحملل )the government equation(الحاكمة :[9][11] [10] آالتي بالشكل تفاضلية بعد تطبيق الفرضيات أعالهالتوالزخم والطاقة إلى معاد )االستمرارية(معادلة حفظ الكتلة 0=      ∂ ∂ + ∂ ∂ y v x u (1) )x(رمعادلة حفظ الزخم تجاه المحو       ∂ ∂ ∂ ∂ +      ∂ ∂ ∂ ∂ +      ∂ ∂ ∂ ∂ + ∂ ∂ −=      ∂ ∂ + ∂ ∂ x v yy u yx u xx p y u v x u u effeffeff µµµρ 2 (٢) )y(معادلة حفظ الزخم تجاه المحور       ∂ ∂ ∂ ∂ +      ∂ ∂ ∂ ∂ +      ∂ ∂ ∂ ∂ + ∂ ∂ −=      ∂ ∂ + ∂ ∂ y u xy v yx v xy p y v v x v u effeffeff µµµρ 2 (٣) ))(1( tt −∗+∗≅ οο βρρ ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٥ ةمعادلة حفظ الطاق         ∂ ∂ ∂ ∂ +        ∂ ∂ ∂ ∂ =      ∂ ∂ + ∂ ∂ y t yx t xy t v x t u eff eff eff eff prpr µµ ρ (٤) دالت آنية يمكن بواسطتها إيجاد قيمة أي خاصية اباستخدام طريقة الحجوم المحددة إلى مع أعاله ت المعادال حولن . قيم الخاصية في النقاط المجاورة بداللة)١(الشكل في كما مركز الحجم المسيطر(p)في النقطة :للجريان المضطرب فهي) k –ε(اما المعادالت الخاصة بالموديل ان المضطرب اللزوجة للجري )٥( )turbulent kinetic energy(معادلة موازنة الطاقة الحركية ( ) ( ) ρε σ µ σ µρρρ −+      ∂ ∂ ∂ ∂ +      ∂ ∂ ∂ ∂ = ∂ ∂ + ∂ ∂ + ∂ ∂ g y k yx k xy k v x k u t k k t k t)( )turbulent kinetic energy dissipation rate(دالة الضائعات للطاقة الحركية : يتم كتابته بالشكل التالي(g)إن حد التوليد          ∂ ∂ ∂ ∂     +      ∂ ∂ +      ∂ ∂ +      ∂ ∂ +      ∂ ∂ +      ∂ ∂ = x v y u z v y v x v y u x u g t 222 22222 µ launder and( كالتـالي وقيم هذه الثوابت معطاة ن الثوابت الواردة في المعادالت السابقة هي ثوابت تجريبية إ spalding,1974(: ε ρµ µ 2k ct ×= ( ) ( ) k cg k c yyxxy v x u t tt 2 21 )( ε ρ εε σ µε σ µρερερε εε εε −+      ∂ ∂ ∂ ∂ +      ∂ ∂ ∂ ∂ = ∂ ∂ + ∂ ∂ + ∂ ∂ ( ) ( ) ( ) ( ) ( )92.12&44.11,3.1,0.1,09.0 ===== εεεσσµ cckc (٦) (٧) (٨) ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٦ حساب عدد رينولد من خالل المعادلة اما لغرض حساب معدل عدد نسلت وفيض ) 17oc( درجة حرارة سطح الزجاج عند لحالة ثبوت لمجمع شمسي هوائي الشروط الحدية )٢(الشكليوضح أمـا ). re≤8000≥5000(رينولدعدد عند )q=530w/m2(اللوح الماص مسلط على طول سطح حراري منتظم .)17oc(المجمع عندالشروط االبتدائية فهي ثبوت درجة حرارة الهواء الداخل الى النتائج والمناقشة نواع من المجمعـات الهـواء الشمـسية الهواء داخل ثالثة ا توزيع درجات حرارة )٥،٤،٣(االشكال تبين والمــــستطيل ,sinusoidal wave-corrugated المتمــــوج ,v-corrugated المتعــــرج( (rectangular-corrugated لزاوية ميل)30o(رينولدعدد عند) 5000≤re≤8000.( الهواء الداخل والخارج هو يالحظ أن أعلى فرق لدرجة حرارة) re=5000(رينولد عدد عند oc)13.65,11.65,9.8 (لمجمعاتلثالثة انواع من ا)وذلك بسبب,على التوالي) المتعرج المتموج والمستطيل و الزيادة الحاصلة في المساحة السطحية نتيجة التعرج للوح االمتصاص المعرض الى االشعاع الشمسي )530w/m2.( درجة حرارة الهواء يقل فرق , ع انواع المجمعاتولجمي) ٨٠٠٠( وصوال الى رينولدعدد عند زيادة فرصة حصوله على الحرارة المكتسبة من االشعاع الشمسي الساقط لالداخل والخارج الن كمية الهواء الداخل تق .)١٣(الشكل كما هو مبين في على المجمع لثالثة عند توزيع قيم سرعة الهواء داخل المجمعات الهوائية ا)٨،٧،٦(االشكال تبين )5000≤re≤8000.( -v(المتعرج عند المجمع) 1.5m/sec(ظة ان اعلى قيمة لسرعة الهواء هييمكن مالح) re=5000(رينولد لعدد corrugated (يرجع سبب ذلك الى التعرجات على شكل حرف , مقارنة مع باقي االنواع)v ( التي تعمل على .ت الهوائيةتلك الممرالداخل الزيادة االضطراب في الجريان بسبب زيادة في االضطرابزداد ولجميع انواع المجمعات ي)٨٠٠٠( وصوال الى رينولد عدد عند زيادة داخل تلك ) vortices( الذي يبن حدوث الدوامات )٩(الشكلكما هو مالحظ في , الجريان سرعة . للوح الماص)التعرجات(التجاويف µρ hdu ××=re (٩) (١٠) k dh nu h ∗ = ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٧ على طـول لـوح ) skin friction coefficient cf (تغير معامل االحتكاك السطحي) ١٠( الشكلبيني المتمـوج ,v-corrugated المتعـرج , flatالمـستوي (االمتصاص والربعة انواع من الـسطوح الماصـة sinusoidal wave-corrugated , ــستطيل ــد)rectangular-corrugatedوالم ــدد عن ــد ع رينول )5000≤re≤8000.( عدد عند )0.14(اذ تصل الى )v-corrugated( مع المتموج تحدث عند المج(cf)ان اعلى قيمة لـ وان أوطيء قيمة له عند المجمع , بسبب حدوث الدوامات المتكونة داخل تلك التجاويف) re=5000(رينولد عدد عند زيادة (cf) يزداد قيمة اذ, )re=5000(رينولد عدد عند)0.04( ذات قيمة )flat plate(يالمستو )re( المجمعاتولجميع انواع. رينولد ولجميع انواع المجمعات الهوائية الشمسية االربعة عددعدد نسلت مع معدل عالقة )١١(الشكليبن تم التوصل الى عالقة لحساب معامل انتقال . رينولدعدد عدد نسلت مع زيادة معدل اذ يزداد ,)30o(ولزاوية ميل وهي )statistica5.5(دام البرنامج المعروف الحرارة بالحمل القسري ولجميع انواع المجمعات بأستخ nm ave cnu prre. وذلك بسبب زيادة(v) قيمة لعدد نسلت تكون عند المجمع نوع المتعرجأعلى إنلوحظ , = عن المجمع )%63(اذ تصل نسبة الزيادة الى, مقارنة مع باقي انواعالمجمعات للوح االمتصاصأضطراب الجريان ).flat plate(المستوي عدد نسلت معدل عدد نسلت للصفيحة المتعرجة الى معدلرينولد مع نسبةعدد عالقة )١٢(الشكليبن ان اعلى قيمة لهذه النسبة تصل عند .)re≤8000≥5000 (د عن(nucorrg./nuflat)للصفيحة المستوية تزداد , )rectangular-corrugated(الصفيحة مقارنة مع )%27.7( تحسنةوبنسب)v-corrugated(الصفيحة .رينولدعدد عدد نسلت مع زيادة معدل نسبة اذ يالحظ هنالك توافق جيد) ٢٠٠٥,جنان مهدي( مقارنة البحث الحالي مع نتائج العملية للباحثة )١٤(الشكل ). ٧٠٠٠(ولكن يزداد عدد نسلت للبحث السابق عند زيادة عدد رينولد عن )re=7000(في النتائج الى حد تاالستنتاجا وع ند المجمع عن الى اقصى قيمة لهادرجات حرارة الهواء الداخل والخارجفي فرق ال قيمةتصل -١ ).v-corrugated(المتعرج ).v-corrugated(عند المجمع نوع المتعرج) cf( أعلى قيمة لـ -٢ رينولد وافضل قيمة له عند المجمع نوع المتعرج عدد عدد نسلت مع زيادة معدل يزداد -٣ )v-corrugated.( ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٨ المصادر 1alison mason, fort collins, jim welch, cindy kline isenhour richard “solar air heating on ridge indian reservation promising application of a tried and true solar technology ” 2hottel h.c., woertz b.b.“performance of flat plate solar collectors”, trans. asme, vol.64, 1942. رسالة ماجستير ، كلية العلوم "دراسة خصائص المجمع الشمسي في العراق " نجيبة عبد اهللا الحمداني ، ٣ ). ١٩٨٢(، الجامعة المستنصرية 4v.k.goel , r.chandra, b.c. raychaudhuri "experimental investigations on single absorber solar air heater " energy convers. mgmt., vol.27, no.4, pp. 343-349, (1987). 5k.g.t. hollands, solar energy 7,108, 1961 6a.a.m. sayilgh, solar energy engineering, academi press, london 1977. 7k. a. joudi & a. i. mohammed “experimental performance of a solar air heater with a “v” corrugated absorber”, energy convers. mgmt vol.26, no. 2, pp. 193-200, 1986. رسالة " دراسة تجریبیة لتحسین أداء سخان الھواء الشمسي بأستخدام مولد الدوامات ", جنان مھدي ھادي ٨ ).٢٠٠٥ (جستير ، قسم هندسة المكائن والمعدات ، الجامعة التكنولوجيةما 9apurba layek, j. s. saini1 and s. c. solanki, “heat transfer and friction characteristics of solar air heater having compound turbulator on absorber plate” advances in energy research (aer–2006). 10 ” pantankar sv. 1980 “numerical heat transfer and fluid flow, hemisphere mcgraw-hill. 11launder b. e. and spalding d.b. “the numerical computation of turbulent flows” (1974), computer methods in applied mechanics engineering 3 pp. 269-289. ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ٩ عند تغير عدد )v-corrugated(توزيع درجات حرارة الهواء داخل مجمع نوع ) ٣(الشكل )re≤8000≥5000(رينولدز re =5000 re =6000 re =7000 re =8000 حددةالحجم المسيطر لطريقة الحجوم الم )١(الشكل p x y e n w s e s w n glass t=17oc air inlet air outlet absorber plate at q=530w/m2 (constant) الشمسي للمجمعالشروط الحدية)٢(الشكل β ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٠ توزيع درجات حرارة الهواء داخل مجمع نوع) ٤(الشكل ) sinusoidal wave-corrugated ( رينولدزعدد عند تغير)5000≤re≤8000( re =5000 re =6000 re =8000 re =7000 ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١١ توزيع درجات حرارة الهواء داخل مجمع نوع ) ٥(الشكل )rectangular-corrugated( رينولدزعدد عند تغير re =6000 re =5000 re =7000 re =8000 ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٢ re =6000 re =5000 re =7000 re =8000 رسوم كنتورية لتوزيع سرعة الهواء داخل مجمع نوع ) ٦(الشكل )v-corrugated( رينولدزعدد عند تغير)5000≤re≤8000( ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٣ رسوم كنتورية لتوزيع سرعة الهواء داخل مجمع نوع) ٧(الشكل ) sinusoidal wave-corrugated( )re≤8000≥5000(رينولدزعدد عند تغير re =7000 re =8000 re =6000 re =5000 ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٤ تورية لتوزيع سرعة الهواء داخل مجمع نوع رسوم كن) ٨(الشكل )rectangular-corrugated( )re≤8000≥5000(رينولدزعدد عند تغير re =8000 re =7000 re =6000 re =5000 ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٥ )re=5000(متعرجة عند متجة سرعة الهواء داخل مجمعات لمجموعة من السطوح ال)٩(الشكل flat plate v-corrugated plate sinusoidal wave-corrugated plate rectangular-corrugated plate ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٦ )re≤8000≥5000(رينولد عدد ولمدى الربعة انواع من اللواح االمتصاصمعامل االحتكاك السطحي )١٠(الشكل 0 0.05 0.1 0.15 0.2 0.25 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 length (m) c f v-corrugated sinusoidal corrugate d re ctangular corrugate d flat plate re =5000 0 0.05 0.1 0.15 0.2 0.25 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 le ngth (m) c f v-corrugated sinus oidal corrugated re ctangular corrugated flat plate re=6000 0 0.05 0.1 0.15 0.2 0.25 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 le ngth (m) c f v-corrugate d sinus oidal corrugated rectangular corrugated flat plate re =7000 0 0.05 0.1 0.15 0.2 0.25 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 le ngth (m) c f v-corrugate d sinus oidal corrugated rectangular corrugated flat plate re =8000 ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٧ 0 50 100 150 200 250 300 350 4000 5000 6000 7000 8000 9000 redh n u av e. nu flat plate=0.039(re^0.967)(pr̂ 0.4) nu rect.corrugated=0.077(re^1.173)(pr̂ 0.4) nu sin-corrugated=0.035(re^1.013)(pr̂ 0.4) nu v-corrugated=0.0828(re^0.939)(pr̂ 0.4) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 4000 5000 6000 7000 8000 9000 redh (n u c o rr ./n u f la t) a ve . rectangular corrugated sinusoidel corrugated v-corrugated الربعة انواع من اللواح االمتصاصرينولد مع عدد نسلت عددعالقة )١١(الشكل رينولد مع نسبة عدد نسلت المتعرج الى المستوي عالقة عدد)١٢( الشكل ٢٠١٠ ١ العدد ٣ المجلد مجلة القادسیة للعلوم الھندسیة ١٨ الربعة انواع من اللواح االمتصاصعالقة عدد رينولد مع درجة حرارة الهواء الخارج )١٣(الشكل 5 6 7 8 9 10 11 12 13 14 15 4000 5000 6000 7000 8000 9000 redh t ou t(o c ) flat rectan sin v-corr مقارنة البحث الحالي مع دراسة سابقة لمجمع هواء شمسي بأستخدم مولد ) ١٤(الشكل الدوامات 0 100 200 300 400 500 600 4000 5000 6000 7000 8000 9000 redh n u av e. flat rectangular sin wave corr. v-corr. جنان مھدي[8] \(microsoft word \\332\\321\\310\\355\) ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٣ مشروع ماء الرمادي الكبير كفاءةنوعية مياه الشرب و تقييم مجيد مطر رمل مدرس مساعد ھندسة السدود والموارد المائية/كلية الھندسة –جامعة ا!نبار majeed_mattar@yahoo.com الخالصــة: وعيــة ميــاه الشــرب فــي مدينــة الرمــادي ضــمن محافظــة األنبــار ،أخــذت تــم إجــراء فحوصــات مختبريــة لتقيــيم ن وتـم .، )المـاء المعـالج(، محطـات الضـخ بعـد عمليـة التعقـيم بـالكلور )نهر الفرات-الماء الخام( العينات من المأخذ شـهرية فيها في عينـات نصـف ) البكتريولوجية(قياس تراكيز بعض الخصائص الفيزيائية ، الكيميائية واألحيائية أظهـرت . وخالل سـنة كاملـة لغـرض تقيـيم نوعيـة ميـاه الشـرب وكفـاءة المحطـة) معدل ثالث نماذج لكل خاصية( لــبعض التــي يــتم تجهيزهــا مــن مشــروع مــاء الرمــادي الكبيــر الشــربميــاه نتــائج الفحوصــات المختبريــة أن نوعيــة وحــدة ٥(مســاوية إلــى العكــارة معــدل ، و) ٧.٦(مســاويا إلــى الــرقم الهيــدروجينيالخصــائص، حيــث كــان معــدل ١١٩(و معـدل القاعديـة مسـاوية إلـى ،) سـم /مايكروسـيمنس ١٢٢٦(الكهربائيـة و معدل اإليصالية،)عكارة دولية مســاوي إلــى م، و معــدل تركيــز أيــون الكالســيو ) لتــر/ملغــم ٣٩٤(و معــدل العســرة الكليــة مســاوية إلــى ،)لتــر/ملغــم ، و معــدل تركيــز أيــون )لتــر /ملغــم ٣٨.٤(يــز أيــون المغنيســيوم مســاوي إلــى ، و معــدل ترك) لتــر /ملغــم ٤٩.٦( و) لتـر /ملغـم ٣٤٧(، و معـدل تركيـز أيـون الكبريتـات مسـاوي إلـى )لتـر /ملغـم ١٩٧.٥(الكلورايد مساوي إلى ة ، أمـــا معـــدل تركيـــز المـــواد الصـــلبة العالقـــ) لتـــر/ملغـــم ٨٨٩( مســـاوية إلـــى tdsتركيـــز األمـــالح الكليـــة معـــدل ، و معـــدل تركيـــز أيـــون )لتـــر /ملغـــم ١٣٠(، و معـــدل تركيـــز أيـــون الصـــوديوم مســـاوي إلـــى ) لتـــر/ملغـــم ٢٤.٢( وهــي ضــمن ) لتــر /ملغــم ٣(، و معــدل تركيــز النتــرات مســاوي إلــى ) لتــر /ملغــم ٤.٩(البوتاســيوم مســاوي إلــى فكانـــت أعلـــى مـــن لية الكهربائيـــةواإليصـــا الكـــدرة،، فيمـــا عـــدا قـــيم تركيـــز أيـــون الكبريتـــات العراقيـــةالمواصـــفات جيدة إال فيزياوية وكيماويةنوعية على الرغم من أن المياه الخام تمتلك خصائص . المواصفات العراقية والعالمية كانـــت ميـــاه الشـــرب خاليـــة مـــن كـــل مـــن العـــدد الكلـــي لبكتريـــا الكوليفـــورم ،أن التلـــوث البكتيـــري فيهـــا عـــالي جـــدًا وهــي ضــمن المواصــفات ) خليــة ٢(كــان معــدل عــدد المســتعمرات البكتيريــة الكلــي حــوالي والبكتريــا المعويــة بينمــا هنالــك مشـاكل حقيقيــة فـي محطـة المعالجــة حيـث لــم تتغيـر الخصـائص النوعيــة للميـاه الخــام . العراقيـة والعالميـة ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٤ ومــن ،ة منتظمــةن عمليــة الصــيانة ال تجــري بصــور الوذلــك . عــن تلــك المتعلقــة بميــاه الشــرب بالمســتوى المطلــوب األمور المهمة التي تـم مالحظتهـا إن إضـافة الشـب ال تمـارس بشـكل دقيـق بحجـة أن الميـاه الداخلـة قليلـة العكـورة . ntu) ٥(حيث ال يتم إضافة الشب عندما تكون الكدرة مساوية إلى أو اقل من ) الفيزيائيــة والكيميائيــة(وصــات تــم دراســة كــل مرحلــة مــن المراحــل الثالثــة مــن خــالل جمــع المعلومــات وأجــراء الفح تم استخدام تجربة عمود الترسيب لحساب كفاءة حوض الترسـيب ، لتحديد المشكلة في المحطةوحسب كل مرحلة وهـي قليلـة حيـث يفتـرض ان تكـون الكفـاءة بالنسـبة لمرحلـة الترسـيب% ) ٣٦( وقد وجد أن المحطة تعمـل بكفـاءة -%٩٧(وكفــاءة )٢٣.٤%( تعمــل بكفـاءة حـوالي مرحلـة الترشـيحبالنســبة ل، ألحـواض الترسـيب%) ٩٠-%٧٠( .الصحة العالمية منظمة مواصفات المواصفات العراقية و ضمن حدودهي في مرحلة التعقيم ،و %) ١٠٠ وهـو برنـامج المطلوبة اإلحصائيةالتحليالت إجراءلغرض )statica 6.0(تم استخدام البرنامج اإلحصائي بعـــد اعتبـــار ان المعلومـــات ، المـــاء النوعيـــة لخصـــائصعـــض التوزيعـــات اإلحصـــائية إحصـــائي وصـــفي إليجـــاد ب لهـا تبـين ان قيمـة معامـل االنحـراف اإلحصـائيالفحص وٕاجراءتمثل عينة شهرالمجموعة لكل متغير خالل فترة (coefficient of skewness) عدلحول قيمة الم مقبولة، أي ان العينة تتوزع بصورة تتباين حول الصفر. .ة، معالجتقييم، نوعية، مياه، الشرب، تلوث: كلمات دالة evaluating the drinking water quality supplied by the large treatment plant in ramadi city majeed mattar ramal anbar university college of engineering\dams & water resources department. abstract: this research evaluate the drinking water quality of the large treatment plant in the ramadi city at al-anbar province .the water samples were taken from which the intake (raw water euphrates), the pumps unit after chlorination (drinking water),. the concentration of some characteristics such as physical, chemical and biological (bacteriological) have been calculated. the samples have been taken twice in the month (average of three samples) for one year, to evaluate the drinking water quality and efficiency of the large water treatment plant in the ramadi. the results show that the ramadi drinking water quality, drinking water has mean (ph) value of (7.6),mean turbidity of(5 ntu), mean electrical conductivity of (1226 µohms/cm), mean alkalinity of (119 mg/l), mean total hardness of (394 mg/l),mean calcium cation concentration of (49.6 mg/l), mean magnesium cation concentration of (38.4 mg/l), mean chloride anion concentration of (197.5 mg/l), mean sulphate concentration of (347 mg/l), mean total dissolved solids concentration of (889 mg/l), mean total suspended solids concentration of (24.2 mg/l), mean sodium cation concentration of (130 mg/l), mean potassium cation concentration of (4.9 mg/l), ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٥ mean nitrate concentration of (3 mg/l),which within local and national standard limitations except the sulphate (so4), turbidity and electrical conductivity which more than the local and national standard limitations, although, the raw water has good physical and chemical water quality characteristics but, highly polluted with bacteria, drinking water was free from both coliform bacteria and (e-coli),while has about (2 cells) of total plat count of bacteria . there are many essential problems in the plant, no significant change could be detected in raw and treated water quality. because of, the maintenance is rarely practiced in time, in addition, the addition of lime is not applied in practice because of the operators thought that the low turbidity water not need lime ,lime not added when turbidity (equal or less than 5ntu). a study for each unit of plant was applied to collect the data and concentration of some characteristics such as physical, chemical have been calculated to determine the problem in the plant. settling column experiment has been carried to determine the sedimentation tank removal efficiency, the sedimentation units has about (36%)removal efficiency, which is must be (70%-90%) ,the filtration units has about(23.4%) removal efficiency and the disinfection stage has about (97% 100%) disinfection efficiency, which are within the iraqi standard limitations and world health organization. (statica) descriptive statistical analysis program has been used to perform the required statistical analysis for the data. this program used to find some statistical distribution for water quality characteristics . each set of data represents an operation period of one month. it was found that data were generally symmetrical and were skewed to the mean values, as measured by the skewness coefficient .which means good distribution about mean value. :ةــالمقدم ) ٨(أشارت تقارير األمم المتحدة إلى أن إستخدام المياه الملوثة ، وغير الصـحية تـؤدي إلـى وفـاة طفـل كـل من سكان الدول النامية %) ٥٠(كما أشارت التقارير إلى أن .ثواني نتيجة إصابته بمرض له عالقة بتلوث المياه مــن جملــة األمــراض فــي الــدول الناميــة تعــود لتلــوث %) ٨٠(لي وحــوا –يعــانون مــن أمــراض لهــا عالقــة بالميــاه إن التطور الصناعي بعـد الحـرب العالميـة .من سكان العالم يستعملون مياه ملوثة%) ١٦(المياه، وأن أكثر من إضـافًة إلـى ذلـك النمـو السـكاني –الثانية ، وٕازدياد معدل التطور الصناعي في الربع األخير من القرن العشـرين كان له األثر الكبير على البيئة بجميع مكوناتها ، فبدأ تأثير مشاكل األمطار الحامضية ، –السريع في تلك الفترة a (....تلــوث الميــاه الســطحية وزيــادة الطلــب علــى الميــاه العذبــة التــي تعتبــر معــدالت وجودهــا شــبه ثابتــة l a d a w i 1 , 2 0 0 يـــــــاه الملوثـــــــة يـــــــتم طرحهـــــــا إلـــــــى األنهـــــــار مـــــــن الم%) ٩٠(حـــــــوالي كالناميـــــــة، هنالـــــــفـــــــي البلـــــــدان )5 سكان العالم يعاني من نقص حـاد فـي يعادل ثلثبما بلدًا، تقريباً ) ٥٠(باإلضافة إلى أن هنالك حوالي .والجداول تـأثير د رجـة الحـرارة علـى ١٩٧٧عـام )al-layla(درس )en. wikipedia.org (.للشـربتـوفر الميـاه الصـالحة ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٦ ) ٧(درجـة الحـرارة يجـب أن تكـون بـين :ماء الحار أو البـارد كثيـرًا يكـون غيـر مرغـوب بـهنوعية المياه ،ووجد أن ال المعلومات حول درجة الحرارة ضـرورية، ألنهـا تـؤثر علـى خصـائص المـاء المختلفـة مثـل . درجة سيليزية ) ١٢(و تعتبــر الكــدرة مــن ),al-layla ١٩٧٧(. الكثافــة ، قابليــة ذوبــان المــواد الكيمياويــة والنشــاط البكتريولــوجي/ اللزوجــة، تــأثير الكــدرة علــى التلــوث البكتيــري ،وجــد ) ١٩٧٩(درس جــزراوي عــام .الخصــائص المهمــة لتقيــيم نوعيــة الميــاه الكـدرة وخاصـة فـي فصـلي الشـتاء والربيـع بسـبب تـأثير األمطـار زيـادة هالتلوث البكتيري سـببالجزراوي إن زيادة فـــي البدايــة كـــان )jazrawi,1979( .الميـــاه الســطحية إلــىبالتـــالي وصــولها التــي تـــؤدي إلــى جـــرف التربــة و ةالغزيــر لكــن لحــين . اللــون فقــط اإلنســان يحكــم علــى نوعيــة الميــاه مــن خــالل خصائصــها الفيزياويــة كــالطعم و الرائحــة و علـى صـحة تطور العلوم الكيمائية و االحيائية و الطبية حيث توفرت الطرق لقياس نوعية المياه و تحديد تأثيرهـا عمليـات يعطـي مؤشـرات بـأن قـد الصالح للشرب لماءلالتقييم النوعي )peavy,1985 (. اإلنسان و الكائنات الحية لوضــع كقاعــدة يســتغل أن يجــب المحطــة، تقيــيم آخــرمــن جانــب .مــاء صــالح للشــرب المعالجــة الحاليــة ال تــؤمن يتضـــمن الميـــاه الصـــالح للشـــربمعالجـــة محطـــاتتحســـين .لمحطـــةا لتطـــوير عمـــلالمهمـــة األمـــورتحديـــد ل خطـــة خطــط .والتطـويرالبحـث ،استشـارةِ بـرامج ، إجـراءات تحسـين التشـغيل، التـدريب ،مثالاألمـور مـن واسـعةمجموعـة ) سـنة واحـدة: ومثال على ذلك( أو بعيدة المدى، البرامج قصيرة المدى قصير األمد تكون قد طويروالت التحسين أمــا بــرامج المجتمــع وتطــويِر بــرامِج وعــي المجتمــعتطــوير عمليــة التشــغيل ، توعيــة علــى ســبيل المثــال،وتتضــمن . َأو تحســين عمليتــي التخثيــر والترشــيح ألحــواض الميــاه ،غطــاء وضــع يمكــن أن تتضــمن بعيــدالمــدى ال ذات جـدول وعمل قد تكون لها كلف مادية عالية ولذلك يتطلب وضع تحليل مفصل والتطوير تطبيق خطط التحسين يرجـع )who,2004 (.فعالـة تلـك التحسـينات أن يراقـب لتأكيـد أنيجـب تطبيـق الخطـِط . أولويـات حسـب األهميـة اهتمــام اإلنســان بنوعيــة المــاء الــذي يشــربه إلــى أكثــر مــن خمســة أالف عــام ، و نظــرا للمعرفــة المحــدودة فــي تلــك لميـــاه و طعمهـــا و رائحتهـــا فقـــط ، و قـــد العصـــور بـــاألمراض و مســـبباتها فقـــد كـــان االهتمـــام محصـــور فـــي لـــون ا بعـض عمليـات المعالجـة مثـل الغليـان –و بشكل محدود خالل فترات تاريخية متباعدة –استخدمت لهذا الغرض و الترشــيح و الترســيب و إضــافة بعــض األمــالح ، ثــم شــهد القرنــان الثــامن و التاســع عشــر الميالديــان الكثيــر مــن ا و روســـيا للنهـــوض بتقنيـــة معالجـــة الميـــاه حيـــث أنشـــئت ألول مـــرة فـــي التـــأريخ المحـــاوالت الجـــادة فـــي دول أوربـــ ) m.klinck(ألجــل تحســين محطــات معالجــة ميــاه الشــرب قــام . محطــات لمعالجــة الميــاه علــى مســتوى المــدن بعمل نموذج آلي مبرمج بالحاسوب مع بعض العمليات اليدوية للسيطرة على كميات المياه الداخلة والخارجة لكل لوحـدات المحطـة حيـث أظهـرت النتـائج فائـدة هـذا اًلنمـوذج يالدينامكالسلوك ، لمعرفة في محطاِت معالجِة وحدة عقدت ندوة علمية بالتعاون مع الهيئـة األمريكيـة )(vansteenkiste, 1975 .في محطات معالجة مياه الشرب محطـــات تنقيـــة الميـــاه بالتقنيـــات م ألجـــل زيـــادة الـــوعي لـــدى مشـــغلي )١٩٨٢(عـــام ) awwa(إلعمـــال الميـــاه واألساليب المتطورة لزيادة كفاءة عمل المحطات، وكذلك وضع الحلول المالئمة لمعالجة المشاكل وتأثيراتهـا علـى محطات تنقية المياه ونوعية المياه المجهزة ، حيث أوضح عدد من البـاحثين انـه يجـب إعـادة النظـر فـي الجوانـب ملــة عنــد عــدم مالئمتهــا لواقــع الحــال الســيما فــي ضــوء المفــاهيم التصــميمية اات العالتشــغيلية والتصــميمية للمحطــ ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٧ وأوصــى أحــد البحثــين بإســتخدام األنابيــب المرســبة )lafoutine,1975( . الحديثــة والمتطلبــات النوعيــة لميــاه الشــرب )tube settler (ي زيادة كفاءة الترسيبحيث يتم إستخدام تلك التقنية لزيادة المساحة السطحية للترسيب وبالتال....) forbes,1980( احد النهج الشـاملة ١٩٨٦برنامج األمم المتحدة للبيئة في عام و يعتبر برنامج اإلدارة السليمة بيئيا للمياه الذي أنشأهُ ة عمليـ.برمتهـاالبرنامج مساعدة الحكومات على إدماج االعتبـارات البيئيـة خـالل شـبكات الميـاه يهدفو . إلدارة المياه و بــذلك يقــل تركيــز د تراكمهــا يــؤدي الســتهالك مكثــف لألوكســجين تحليــل الطحالــب مــع المــواد العضــوية األخــرى بعــ المذاب في الماء و المتوفر الستعمال الكائنـات النباتيـة و الحيوانيـة فـي الميـاه نتيجـة لـذلك تتضـرر جـودة األوكسجين اآلمـنِ و لـى المـاء الصـالح للشـرِب عصـول حاللذين بإمكانهم المياه حسب منظمات األمم المتحدة فإن نسبة السكان ا مـن المحتمـل أن تقنيـات التحليـل الجديـدة سـوف تتطـور أكثـر )unicef website articles (.%)٨٥(فـي العـراق هـي ممــا يــؤدي إلــى معرفــة عناصــر ليســت معروفــه اآلن بوجودهــا فــي المــاء و هكــذا فــأن علــم نوعيــة الميــاه ســيبقى تحــديا )peavy,1985 ( .دس للسنوات القادمة للمهن :هـدف البحث تقيــيم نوعيــة ميــاه تقيــيم كفــاءة مشــروع مــاء الرمــادي الكبيــر و الرئيســي مــن هــذه الدراســة هــو الهــدفإن عنـد ) المتـوفرة ( الرمادي و ذلك بأجراء بعض الفحوصات الفيزياوية و الكيماويـة و البايولوجيـة في مدينة الشرب و مقارنتها ) ٢٠٠٩ شرين األولوحتى ت ٢٠٠٨ شرين الثانيت(أخذ وبعد عملية الكلورة وعلى مدى سنة كاملة الم مع المواصفات العالمية و المحلية و اقتراح ما يمكن عمله بما يتالءم مع المياه المعالجة و معرفة المشـاكل التـي . عية جيدة تعيق و تؤثر على معالجة المياه وصوال إلى مياه شرب ذات نو يجـب أنالمـاء الصـالح للشـرب ):water quality standards(مواصـفات الميـاه القياسـية ).who( الحكومـــات ومنظمــة الصـــحة العالميـــة مـــن قبــلللميــاه والتـــي تحــدد لنوعيـــةايكــون ضـــمن المواصــفات )argaw,2001( أول مواصفة لمياه الشرب وضعت في عام)مـالح و المـواد السـامة توضح الجداول األ.) ١٩١٤ المســموح بهــا فــي ميــاه الشــرب ، و تختلــف األضــرار الناتجــة مــن اســتعمال الميــاه التــي تحــوي اكيزو الضــارة بــالتر اكبــر مــن المســموح بهــا مــن مــادة ألخــرى فــبعض المــواد لــه تــأثير ســام مباشــر مثــل الرصــاص و الزئبــق و اكيــزتر ٠.٠٥(عضاء الجسم مثـل األلمنيـوم فيجـب أال يزيـد تركيـزه عـن السلينيوم ، و البعض األخر له أضرار لبعض أ و البــاريوم يــؤثر علــى . جــزء فــي المليــون لتــأثيره علــى مرضــى الكلــى )٠.٢٠(أقصــى جــزء فــي المليــون و بحــد) القلب و األوعية الدموية و األعصاب ، و الكادميوم يتراكم فـي الكليـة و الكبـد و لـه عالقـة بارتفـاع ضـغط الـدم ، )tebbutt,1998( .أن نقص أو زيادة الفلور عن التركيزات الواردة بالجداول يسبب بعض أمراض األسنان كما لسـنة )who( المواصـفات الكيميائيـة لميـاه الشـرب حسـب منظمـة الصـحة العالميـة) ١( رقم الجداول ويوضح )٢٠٠٤() tebbutt, 1998) ٢٠٠١(لسـنة )٤١٧(رقـم العراقيـةوالمواصـفة(. )ministry of municipalities &public works,2008( ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٨ :مشروع ماء الرمادي الكبير يعتبــر مشــروع مــاء الرمــادي الكبيــر مــن المشــاريع الضــخمة فــي مدينــة الرمــادي لتوزيــع ميــاه الشــرب لســكان تلــك . م١٩٨٥م، و تـم تنفيـذ هـذا المشـروع و تشـغيله سـنة ١٩٨١قد وضع حجر األسـاس لهـذا المشـروع سـنة . المدينة مليـون لتـر بـاليوم )١٤٤(طاقة المشروع التصميمية تبلـغ ).conventional(يتم معالجة المياه بالطريقة التقليدية يقـع مشـروع مـاء الرمـادي الكبيـر علـى نهـر . صورة جوية لمشروع مـاء الرمـادي الكبيـر )١(رقم شكلالوضح ي . المشروع مركز المدينة وأحياء عديدة وتم تقسيم األحيـاء مدينة الرمادي ، يغذي هذا –الفرات في محافظة األنبار .)٢(والصورة رقم )٢(الجدول رقم نسبًة لموقعها من المشروع وخطوط التوزيع كما في :الترسيبكفاءة حوض كثافة فإنهـا تتسـارع إلـى عند وضع حبيبة في سائل اقل منه أنه يستند علىالمثالي تصميم حوض الترسيب إن . المغمـور مـع قـوة اإلعاقـة االحتكاكيـة ممـا يـؤدي إلـى ترسـبها وزن الجسـملغ سـرعة منتظمـة وبعـدها يتسـاوى إن تب عندما يترك عالق من الجسيمات المختلفة الكثافة لتترسب ،فإن لكل جسيمة سرعة ترسيب مختلفة عن الجسيمات حجم أو (الجسيمات ذات السرعة األكبر تلحق بها ) اقل كثافة(األخرى، وعليه فأن الجسيمات ذات السرعة األقل اتحاد الجسيمات وتكوينها للمتلبدات وخاصـة إلىوهذه الحالة تولد العديد من التصادمات التي تؤدي ). وزن أكبر ) 4(، يــتم إضــافة الشــب بشــكل محلــول بمعــدل عنــد إضــافة المــواد المســاعدة علــى تكــوين الملبــدات مثــل الشــب التوزيـــع الحجمـــي أمـــا يتطلـــب حـــوض ترســـيب أيكفـــاءِة حســـاب وتقـــدير .فـــي حـــوض المـــزج الســـريع ٣م/غـــرام isoremoval(منحنيـــات متســـاوية اإلزالـــة للجســـيمات العالقـــة َأو اســـتخدام عمـــوِد الترســـيب حيـــث يـــتم رســـم curves ( . بعــد معرفــة درجــة تركيــز ، مختلفــة والزمــان مختلفــة لكــل عمــق معــين أعمــاقيــتم اخــذ العينــات مــن خــالل زمــن معــين وحســاب ) بواســطة جهــاز عمــود الترســيب( توبأخــذ عينــا، ) co(العالقــة للمــاء الخــام المــواد ) h1,h2,…..,hn(ألعماق مختلفة من حـوض الترسـيب ) c1, c2,….., cn(درجة تركيز المادة العالقة لها القة يمكن حسـابها العنسبة الجسيمات من نتائج تجربة عمود الترسيب حيث يمكن حساب . ) ١(الحظ شكل رقم )ahmed ,1995( .)١( من المعادلة )1( ο = c c s ij ij ) .tij(وزمن معين ) hij(تمثل نسبة الجسيمات الصلبة المتبقية عند عمق معين ) : sij/ (حيث أن )cij : ( تمثل تركيز الجسيمات الصلبة العالقة الكلية المتبقية بوحدات) (عند عمـق معـين ) لتر/ملغمhij ( وزمـن )tij. ( )ahmed ,1995(معين ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٣٩ )co : ( تركيز الجسيمات الصلبة العالقة الكلية للماء الخام بوحدات) لتر/ملغم. ( .)٢(رقم يمكن إيجادها من المعادلة لكل عمق وزمن معين )xij( المزالةذلك فان نسبة الجسيمات ك ( )[ ] )2(100*1 ο−= sx ij وبإعـادة اخـذ .)tij(وزمن معين ) hij(بة الجسيمات التي سيتم إزالتها عند عمق معين تمثل نس: )xij/ (حيث أن لخـواص المـواد العالقـة كمـا )ات اإلزالـة المتسـاويةمنحنيـ( خارطة كنتوريـةالعينات لفترات زمنية مختلفة يمكن رسم )ahmed ,1995( . )٣(حساب اإلزالة الكلية كما في المعادلة رقم يتم ومنها.)أ٣(في شكل موضح )3)( 2 ()/........() 2 ()/( 1211 ++×∆+ + ×∆= nntntt rr hh rr hhr (%) .تمثل اإلزالة الكلية للجسيمات الصلبة ) : rt/ (حيث أن )∆hi : ( عمق نقطة أخذ العينة رقم)i) (متر. ( )n :( العيناتعدد نقاط أخذ. )ht :( إرتفاع الحوض) متر(الكلي ) عمود الترسيب. ( )ri+1 , ri : (نيين بينهما عمق مقداره تمثل نسبة اإلزالة لمنح)∆hi. ( : كفاءة المرشحات العليا فان مسامات الطبقة الترشيحية ، المرشحات المستخدمة في المحطة هي مرشحات الرمل السريعة تكون كبيرة نوعا ما مما يسهل معه تخلل الحبيبات والشوائب إلى داخل )ةخشنبنوعية الرمل يستخدم فيها التي و ( .فان كفاءة المرشح للتخلص من الشوائب تزداد مما يسهل معه ترشيح المياه ذات العكارة الكبيرةوبذا . المرشح :الماء) تطھير ( كفاءة عملية تعقيم من المعروف أن الترشيح ال يعمل بكفاءة كبيرة إلزالة البكتريا والفيروسات ، وذلك لصغر مقاسها والذي شحات الرمل السريعة مياه صالحة من النواحي البكتروبايلوجية ، مما ذا ال تنتج مر لهيكرون و ام واحد يقل عن على عدد الجراثيم تعتمد درجة قتل الجراثيم . )ahmed ,1995( إلزالة البكتريا والجراثيم إضافة الكلوريوجب غل في كفاءة المطهر للتغل: ويعتمد قتل الجراثيم على عوامل عديدة متداخلة مع بعضها مثل . الموجودة أصال كمية أن، قوى خاليا الكائنات الحية والزمن الالزم للمطهر للتغلغل وكمية المطهر وعدد ونوع الجراثيم المتواجدة ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٠ حسب ٣م/غم )٥٣(الماء قبل عملية الضخ تتراوح بين إلىغاز الكلور المضافة بواسطة أجهزة إضافة الكلور أن الماء صالحا للشرب إذا أحتوي علي المواصفة األمريكية تعتبر . درجة حرارة الماء ونسبة التلوث البكتيري بينما الوسط المغذيعلي بيئة اإلطباقمقدرة بطريقة ملفي ميكروب ١٠٠أقل من عدد كلي من البكتريا )ahmed ,1995( .مل ١٠٠خلية في ٥٠توصي منظمة الصحة العالمية بان ال تزيد عن :جمع العينات علـب مصـنوعة مـن مـادة بـولي اثلـين سـعة الخاصة بالتحليل الكيميائي والفيزيـائي بإسـتخدام الماءتم جمع عينات ، قبل عمليـة الترشـيح، محطـات )نهر الفرات-الماء الخام( أخذت العينات من أربعة أماكن هي المأخذ، لتر واحد مـاء الرمـادي الكبيـر يتكـون تم عمـل عمـود ترسـيب فـي مشـروع .)الماء المعالج(الضخ بعد عملية التعقيم بالكلور متــر مماثــل لعمــق حــوض الترســيب ) ٥(ســم وبطــول ) ١٩(أنــج ) ٧.٥(مــن أنبــوب بالســتك بقطــر داخلــي مقــداره أخــذت عينــات مــن مــاء . متــر ) ٥،٤،٣،٢،١(أنــج ألخــذ العينــات لألعمــاق ) ١(وتــم عمــل فتحــات دائريــة بقطــر ومــن ثـم تــم إســتخدام ) لتــر/ملغـم(بوحــدات ) co(ركيــز األولـي النهـر لقيــاس تركيـز المــواد الصــلبة العالقـة لتمثــل الت مضخة تعمل بالوقود لسحب الماء من حوض المزج السـريع لملـيء عمـود الترسـيب ، وتـم أخـذ العينـات مـن نقـاط ،وكـذلك تـم أخـذ عينـات مـن ميـاه النهـر الخـام وحسـاب تركيـز سـاعة) ٥،٤،٣،٢،١،٠(أخذ العينات عنـد األزمـان وحســاب الجرعــة المالئمــة مــن الشــب لهــا ) لتــر/ملغـم(بوحــدات ) co(العالقــة لتمثــل التركيــز األولــي المـواد الصــلبة أمـا عينـات الفحـص البكتريولـوجي .وٕاضافتها إلى عينة مياه النهر في عمود الترسيب لمعرفة الفرق بين العمليتين نصـف شـهرية لمشـروع مـاء الرمـادي قناني بالستيكية معقمة ، تم عمـل زيـارات تم جمع عينات الماء بواسطة فقد وأخــذ بعــض المعلومــات مــن إدارة ).٢٠٠٩-وحتــى تشــرين أول ٢٠٠٨-تشــرين ثــاني(ســنة كاملــة خــاللالكبيــر و وحفـظ جمـع فـي القياسـية الطـرق ومشغلي المشروع، وعمل ثالث مكررات لكـل عينـة ألجـل الفحـص ، واسـتخدمت جهـزة مـن قبـل باسـتخدام األجهـزة والمـواد الم وصـات للعينـات، وقـد تـم أجـراء الفح(awwa, 1995)العينات وتحليل turbidity(قيســت درجــة الحــرارة باســتخدام محــرار زئبقــي ،تــم قيــاس الكــدرة باســتخدام جهــاز ،شــركات عالميــة meter,hach2100( أمــــا األس الهيــــدروجيني ،اإليصــــالية الكهربائيــــة والمــــواد الصــــلبة الذائبــــة فقــــد قيســــت، والعسرة الكلية بطريقة ،الكلورايد ، تم قياس القاعدية) ph-meter ,hanna co., hi-225(بإستخدام جهاز المـواد الصـلبة العالقـة و النتـرات بإسـتخدام جهـاز الكبريتـات ، التسحيح ،تم قياس كل مـن الكالسـيوم ،المغنيسـيوم ، )spectro photometer ( وتم قياس الصـوديوم والبوتاسـيوم باسـتخدام جهـاز ،)flame photometer (، تـم والموجـودة )jar-test, lab tech co., ljt-060( فحـص الجـرة تحديد جرعة الشب المثلى باستخدام جهاز .في مختبرات محطة التصفية لعدم توفرها في مختبرات الكلية ولضمان سرعة أجراء الفحص وعدم تلوث العينات (awwa, 1995) :والنتائجالحسابات ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤١ :الترسيبكفاءة ١ المتبقية في كل المواد الصلبة العالقة واستخراج تركيز )settling column(إجراء تجربة عمود الترسيب بعد . ) أ-٣(رقم الجدول في كل عينة وكما موضح في للمواد الصلبة العالقة نسبة اإلزالة المئويةواستخراج ،عينة ساعة ) ٥(خط عمودي عند زمن مقداره يتم رسم، )أ٣(الشكل رقم يتم رسم منحنيات اإلزالة المتساوية كما في :وكاآلتي حوض الترسيب لنستخرج كفاءة اإلزالة ،)٣(رقمبتطبيق معادلة .الترسيبزمن المكوث في حوض ( %36) 2 10030 () 5 5.1 () 2 301.18 () 5 5.3 ( = + ×+ + ×=tr تجربة حيث تم تحديد جرعة الشب المثالية ومن ثم إجراء أما نتائج تجربة عمود الترسيب في الحالة الثانية الشكل يتم رسم منحنيات اإلزالة المتساوية كما في . )ب٣(رقم الجدول وكما موضح في عمود الترسيب ، لتر وجرعة الشب /ملغم) ٥١(فقد كان التركيز ا;ولي للمواد الصلبة العالقة مساوي إلى ،)ب٣(رقم ) ٣(رسيب حسب المعادلة رقم لتر لتكون كفاءة عملية اbزالة في تجربة عمود الت/ملغم)١٥(الم@ئمة .، لذا فأن عملية إضافة الشب k تتم بصورة صحيحة من قبل المشغلين %) ٧١.٦( إلىمساوية : كفاءة المرشحات ٢ تركيز المواد الصلبة دخالل إيجامن بالنسبة للتخلص من المواد العالقة الصلبة يتم حساب كفاءة المرشحات :اآلتية )٤(رقم لمعادلةالترسيب طبقًا ل العالقة في الماء الخارج من حوض .).4)(.1( te rcc −×= ο ومن ثم ).لتر/ملغم(يمثل تركيز المواد الصلبة العالقة في الماء الخارج من حوض الترسيب ) : ce/ (حيث أن :إيجاد كفاءة المرشحات وحسب المعادلة التالية .)5........(.....................100)(1( ×−= e out f c c e : لمرشحاتكفاءة ا وعليه فان ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٢ %4.23100) 14 28.17 (1( =×−=fe المرشحات ستكون تراكيز المrواد الصrلبة العالقrة إلىجرعة الشب المثلى فان المياه الداخلة إضافةوفي حالة سrتكون ميrاه %) ٢٣.٤( إلrىلتر ، وعند اعتبار كفاءة المرشحات مسrاوية /ملغم) ١٤.٤٨( إلىالكلية مساوي .تر من المواد الصلبة العالقة ل/ملغم) ١١.٠(الشرب تحتوي على . كفاءة التعقيم -٣ ، خـالل فتـرة الدراسـةنتائج المعدل الشهري للعينات التي تم أخـذها مـن المحطـة ) ٥(و ) ٤(الشكلين يوضح .العدد الكلي للبكتريا وفحص البكتريا المرضيةمتوسط والتي تم فيها فحص متوســط العــدد و متوســط العــدد االحتمــالي لبكتريــا القولــونكــل مــن نســبة اإلزالــة الكليــة ل) ٢٠(الشــكل رقــم يبــين عـــــــدد المســــــــتعمرات البكتريولوجيــــــــةونســــــــبة اإلزالـــــــة الكليــــــــة ل%) ١٠٠(كانــــــــت القولونيـــــــة للبكتريــــــــااالحتمـــــــالي .طول فترة الدراسة %) ٩٧.٥٧(كانت :التحليل ا9حصائي للنتائج -٤ واسع ، حيث تم حسـاب كـل مـن إحصائيوهو برنامج ) statica 6.0(تم استخدام البرنامج اإلحصائي ا مبـين مـوك مـن ميـاه النهـر وميـاه الشـرب للكـ االنحراف المعياري، معامـل التغـاير ، ونسـبة الخطـأ القياسـي ، .)٧(و )٦(رقم ينالجدول في : لنوعية المياه النتائج المختبرية ،باإلضــافة إلــى ) المعالجــة(نتــائج المختبريــة لميــاه الشــرب أدنــاه النتــائج المختبريــة لكــل مــن ميــاه النهــر ، ال .األشكال الخاصة بكل عنصر من عناصر تقييم نوعية المياه الفيزياوية ، الكيمياوية والبكتريولوجية سنة كاملة خاللإعتمادًا على نتائج الفحوصات المختبرية التي أجريت في مختبر مشروع ماء الرمادي الكبير و ومقارنـة ) ٢٠إلـى ٢(واألشـكال ) ١١إلى ٤(الجداول ) ٢٠٠٩-وحتى تشرين أول ٢٠٠٨-انيتشرين ث( .في المشروعالمعالج النتائج المختبرية مع المحددات العالمية والعراقية يمكن إعطاء صورة عن نوعية الماء :وفي ما يلي شرح موجز لكل عنصر من عناصر تقييم المياه سنة كاملة، درجة الحرارة لميـاه النهـر تتـراوح بـين خالل قيم درجة الحرارة ) ٤(الشكل رقم نيبي: درجة الحرارة -١ ، ) ٢٢.٨(وبمعدل ) ١٢-٣١(الشرب فكانت قيم درجة الحرارة تتراوح بين ، أما مياه)٢١.٦(وبمعدل ) ١١-٣١( .وهي ضمن المواصفات العراقية والدولية ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٣ وبمعـدل ) ٨-٣٣.٨(سنة كاملة، الكـدرة لميـاه النهـر تتـراوح بـين خاللكدرة قيم ال) ٥(الشكل رقم يبين: الكدرة-٢ وهـــي ضـــمن المواصـــفات العراقيـــة ) ٥(وبمعـــدل ) ٤-٨(،أمـــا ميـــاه الشـــرب فكانـــت قـــيم الكـــدرة تتـــراوح بـــين ) ١٥( . طول فترة الدراسة %)٦٦.٦(نسبة اإلزالة الكلية للكدرة وكانت )٢٠(الشكل رقم يبين . والدولية سـنة كاملـة، الـرقم الهيـدروجيني لميـاه خـاللقـيم الـرقم الهيـدروجيني ) ٦(الشكل رقـم يبـين: الرقم الهيدروجيني-٣ ، أمـــا ميـــاه الشـــرب فكانـــت قـــيم الـــرقم الهيـــدروجيني تتـــراوح بـــين )٧.٩٥(وبمعـــدل ) ٧.٩-٨.١(النهـــر تتـــراوح بـــين .وهي ضمن المواصفات العراقية والدولية )٧.٦٨(وبمعدل ) ٧.٤-٧.٩( سـنة كاملـة، اإليصـالية الكهربائيـة خـاللقيم اإليصالية الكهربائيـة ) ٧(الشكل رقم يبين: اإليصالية الكهربائية-٤ ،أمـا ميـاه ) (µohoms /cm )١٥٥٥(وبمعـدل ) (µohoms/cm )١٣٥٦ ١٨٩١(لميـاه النهـر تتـراوح بـين )١٢٢٦(وبمعـدل ) (µohoms /cm )١٠٥٤ ١٤٤٣(الشـرب فكانـت قـيم اإليصـالية الكهربائيـة تتـراوح بـين µohoms /cm) ( وهي أعلى من المواصفات العراقية والدولية البالغة ،)نسبة )٢٠(الشكل رقم يبين ). ١٠٠٠ . طول فترة الدراسة %)٢١.١(إنخفاض قيمة اإليصالية الكهربائية وكانت لة، العسرة الكلية لميـاه النهـر تتـراوح بـين سنة كام خاللقيم العسرة الكلية ) ٨(الشكل رقم يبين: العسرة الكلية-٥ وبمعــدل ) ٣١٩-٤٧٤(،أمــا ميــاه الشــرب فكانــت قــيم العســرة الكليــة تتــراوح بــين ) ٤٤١(وبمعــدل ) ٣٦٠-٤٨٨( نسـبة اإلزالـة الكليـة للعسـرة وكانـت )٢٠(الشـكل رقـم يبـين . ، وهي ضمن المواصفات العراقيـة والدوليـة ) ٣٩٤( .ة طول فترة الدراس%)١٠.٧( ســنة كاملــة، تركيــز الكالســيوم لميــاه النهــر تتــراوح بــين خــاللقــيم الكالســيوم ) ٩(الشــكل رقــم يبــين: الكالســيوم-٦ ، )٤٩.٦(وبمعـــدل ) ٣٢-٧١(، أمـــا ميـــاه الشـــرب فكانـــت قـــيم الكالســـيوم تتـــراوح بـــين )٩٦(وبمعـــدل ) ٧٢-١٠٥( نسـبة إنخفـاض تركيـز الكالسـيوم الكليـة وكانـت ) ٢٠(الشـكل رقـم يبـين. وهي ضمن المواصـفات العراقيـة والدوليـة . طول فترة الدراسة %)٤٨.٣( سـنة كاملـة،تركيز المغنيسـيوم لميـاه النهـر تتـراوح خـاللقـيم المغنيسـيوم ) ١٠(الشـكل رقـم يبـين: المغنيسيوم -٧ ، ) ٣٨(دل وبمعـ) ٣٢-٥٤(،أما ميـاه الشـرب فكانـت قـيم المغنيسـيوم تتـراوح بـين ) ٤٩(وبمعدل ) ٣٧-٨٠(بين نسبة إنخفاض تركيز المغنيسيوم الكليـة وكانـت ) ٢٠(الشكل رقم يبين. وهي ضمن المواصفات العراقية والدولية .طول فترة الدراسة %)٢٢.٥٨( ســنة كاملــة، تركيــز الكلورايــد لميــاه النهــر تتــراوح بــين خــاللقــيم الكلورايــد ) ١١(الشــكل رقــم يبــين: الكلورايــد -٨ وبمعـــدل ) ١٧٥-٢١٧(،أمـــا ميـــاه الشـــرب فكانـــت قـــيم الكلورايـــد تتـــراوح بـــين ) ٢٢٠.٥(دل وبمعـــ) ٢٥٠-١٨٨( نسـبة إنخفـاض تركيـز الكلورايـد ) ٢٠(الشـكل رقـم يبـين. ، وهي ضمن المواصـفات العراقيـة والدوليـة ) ١٩٧.٥( .طول فترة الدراسة %)١٠.٤٣(الكلية وكانت سـنة كاملـة،تركيز الكبريتـات لميـاه النهـر تتـراوح بـين خـاللريتـات قـيم الكب) ١٢(الشكل رقـم يبـين: الكبريتات -٩ وبمعــــدل ) ٢٠٠-٤٢٤(،أمــــا ميــــاه الشــــرب فكانــــت قــــيم الكبريتــــات تتــــراوح بــــين ) ٣٦٦(وبمعــــدل ) ٢١٢-٤٤٩( ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٤ نســبة ) ٢٠(الشــكل رقــم يبــين) . لتــر/ملغــم ٢٥٠(وهــي اكبــر مــن المواصــفات العراقيــة والدوليــة البالغــة ) ٣٤٧( .طول فترة الدراسة %)٥.٢(الكبريتات الكلية وكانت إنخفاض تركيز سـنة كاملـة،تركيز المـواد خـاللقـيم المـواد الصـلبة الذائبـة ) ١٣(الشـكل رقـم يبين: : المواد الصلبة الذائبة -١٠ ،أمـــا ميـــاه الشـــرب فكانـــت قـــيم المـــواد ) ٩٥٥(وبمعـــدل ) ٨٦٣-١٠٤٧(الصـــلبة الذائبـــة لميـــاه النهـــر تتـــراوح بـــين يبــين. ، وهــي ضــمن المواصــفات العراقيــة والدوليــة ) ٨٨٩(وبمعــدل ) ٨٤٩-٩٤٥(الذائبــة تتــراوح بــين الصــلبة .طول فترة الدراسة %)٦.٩(نسبة إنخفاض تركيز المواد الصلبة الذائبة الكلية وكانت ) ٢٠(الشكل رقم ســنة كاملــة،تركيز المــواد اللخــقــيم المــواد الصــلبة العالقــة ) ١٤(الشــكل رقــم يبــين: واد الصــلبة العالقــة مــال-١١ ،أمــا ميــاه الشــرب فكانــت قــيم المــواد الصــلبة ) ٤١(وبمعــدل ) ١٤-٩٧(الصــلبة العالقــة لميــاه النهــر تتــراوح بــين الشكل رقـم يبين. ، وهي ضمن المواصفات العراقية والدولية ) ٢٥.٧(وبمعدل ) ١٠-٦٠.٥(العالقة تتراوح بين الشـكل رقـم يبـين .طـول فتـرة الدراسـة %)٣٧.٣(لصلبة العالقة الكلية وكانـت نسبة إنخفاض تركيز المواد ا) ٢٠( .كفاءة إزالة المواد الصلبة العالقة لكل مرحلة من مراحل المحطة )٢١( سنة كاملـة، تركيـز الصـوديوم لميـاه النهـر تتـراوح خاللقيم الصوديوم ) ١٥(الشكل رقم يبين: : الصوديوم -١٢ وبمعــدل ) ١١٤-١٥٩(،أمــا ميــاه الشــرب فكانــت قــيم الصــوديوم تتــراوح بــين ) ١٥٠(وبمعــدل ) ١٢٧-٢١٠(بــين نســبة إنخفــاض تركيــز الصــوديوم ) ٢٠(الشــكل رقــم يبــين. ، وهــي ضــمن المواصــفات العراقيــة والدوليــة ) ١٣٠( .طول فترة الدراسة %)١٣.٣(الكلية وكانت سنة كاملة، تركيز البوتاسيوم لمياه النهر تتراوح خاللقيم البوتاسيوم ) ١٦(الشكل رقم يبين: : البوتاسيوم -١٣ ) ٤.٩(وبمعــدل ) ٤-٦.٤(،أمــا ميــاه الشــرب فكانــت قــيم البوتاســيوم تتــراوح بــين ) ٦(وبمعــدل ) ٤.٤-٧.٩(بــين نسبة إنخفاض تركيـز البوتاسـيوم الكليـة وكانـت ) ٢٠(الشكل رقم يبين. وهي ضمن المواصفات العراقية والدولية .ول فترة الدراسة ط%)١٨.٣( ســنة كاملــة، تركيــز النتــرات لميــاه النهــر تتــراوح بـــين خــالل)النتــرات(قــيم ) ١٧(الشــكل رقــم يبــين: النتــرات-١٣ ، ) ٣.٠(وبمعـدل ) ٢.٩-٣.١(بـين حتتـراو ) no3(،أمـا ميـاه الشـرب فكانـت قـيم ) ٣.٥(وبمعدل ) ٣.٤-3.55( نســبة إنخفــاض تركيــز النتــرات الكليــة وكانــت ) ٢٠(رقــم الشــكل يبــين. وهــي ضــمن المواصــفات العراقيــة والدوليــة .طول فترة الدراسة %)١٤.٣( عـدد الخاليـا البكتيريـة الموجـودة فـي كـل مـن ميـاه النهـر،)١٨،١٩(األشـكال تبين:المعايير البكتريولوجية -١٤ فـي ميـاه المشــروع ) يكــوال–اإلي (تظهــر النتـائج المختبريـة عــدم وجـود كـل مــن بكتريـا الكوليفـورم و. ميـاه الشـرب متوسـط العـدد نسـبة اإلزالـة الكليـة لكـل مـن ) ٢٠(الشـكل رقـم يبـين. المعالجة وذلك بفعل عملية التعقيم بالكلور عدد ونسبة اإلزالة الكلية ل%) ١٠٠(كانت القولونية للبكتريامتوسط العدد االحتمالي و االحتمالي لبكتريا القولون .طول فترة الدراسة %) ٩٧.٥٧(كانت المستعمرات البكتريولوجية :المنــــاقشة ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٥ المحطــة قيــد تتظهــر النتــائج أن المــاء المعــالج لــه نفــس خصــائص المــاء الخــام تقريبــًا، بتعبيــر آخــر، وحــدا هذا يؤكد بـأن وحـدات المحطـة المختلفـة ال تـؤدي عملهـا بشـكل . الدراسة ال تظهر كفاءة اإلزالة المتوقعة للملوثات لـم حيـثإعتمادًا على هـذه الحقيقـة ، فـأن هـذه المحطـة بـدت وكأنهـا مجـرد سلسـلة مـن وحـدات مـرور الميـاه . جيد كانــت كفــاءة حــوض الترســيب كثيــرًا، تتغيــر الخصــائص النوعيــة للميــاه الداخلــة إلــى المحطــة عــن الميــاه المعالجــة -%٧٠(أحـواض الترسـيب مـابين حيـث يفتـرض ان تكـون كفـاءة اإلزالـة فـي وهي قليلة جداً %) ٣٦(مساوية إلى ويعـود ذلـك إلـى عـدم ضـبط جرعـة حسب تجربة عمود الترسيب الحقليـة%) ٣٦(بينما كانت مساوية إلى %) ٩٠ كما تبين أن صيانة الوحدات المختلفة ال يجري بشكل منتظم وفـي حـال إجـراء الشب في حوض المزج السريع ، وتبــين كــذلك وجــود بعــض األعطــال مثــل توقــف عمــل . عمــل الصــيانة فــأن ذلــك يســتدعي إيقــاف المحطــة عــن ال أن وحــدات المحطــة المختلفــة ال تــؤدي عملهــا بشــكل جيــد ، .الترســيب فــي أحــواض ) scrubbers(القاشــطات بالنســبة %) ٢٣.٤(بالنســبة لمرحلــة الترســيب ، وكفــاءة % ) ٣٦(حيــث أن كفــاءة حــوض الترســيب مســاوية إلــى المـواد العالقــة ةأن كفــاءة المحطـة الكليـة فـي إزالـ. فـي مرحلـة التعقـيم %) ١٠٠-%٩٧(لمرحلـة الترشـيح وكفـاءة من المواد العالقة في أحواض %) ٩٠-%٧٠(وهي نسبة قليلة جدًا حيث يفترض إزالة مانسبته %) ٥٩.٤(تبلغ ) steel,1979. (الترسيب فقط يــتم يعــدم ضــبط جرعــة محلــول الشــب التــفــي أحــواض الترســيب كمــا ســبق ذكــره تعــود إلــى ةإن عــدم كفــاءة اإلزالــ وكــذلك اليــتم اضــافته عنــدما تكــون الكــدرة أقــل أو يســاوي ٣م/غــرام) 4(إضــافتها إلــى حــوض المــزج الســريع بمعــدل )5ntu ( أو يــتم إضــافتها فــي فتــرة التشــغيل الصــباحي فقــط ،وبالتــالي دخــول المــاء إلــى وحــدة المرشــحات محمــًال لقـة ممـا يـؤدي إلـى إنخفـاض فـي كفـاءة المرشـحات ، باإلضـافة إلـى أن عمليـة تبـديل بتراكيز من المواد الملوثة العا أما نتائج تجربة عمود .سنوات وعدم تنظيم عملية غسل المرشحات ) ٣(لم تتم منذ حوالي ) الرمل(وسط الترشيح وكما موضح ترسيب ،ومن ثم إجراء تجربة عمود الالترسيب في الحالة الثانية حيث تم تحديد جرعة الشب المثالية لتــر وجرعــة /ملغــم) ٥١(فقــد كــان التركيــز األولــي للمــواد الصــلبة العالقــة مســاوي إلــى . )ب-٣(رقــم الجــدول فــي ) ٣(لتــر لتكــون كفــاءة عمليــة اإلزالــة فــي تجربــة عمــود الترســيب حســب المعادلــة رقــم /ملغــم)١٥(الشــب المالئمــة وفــي حالــة .ب ال تــتم بصــورة صــحيحة مــن قبــل المشــغلين ، لــذا فــأن عمليــة إضــافة الشــ%) ٧١.٦(مســاوية إلــى إضافة جرعة الشب المثلى فـان الميـاه الداخلـة إلـى المرشـحات سـتكون تراكيـز المـواد الصـلبة العالقـة الكليـة مسـاوي ستكون مياه الشرب تحتوي على %) ٢٣.٤(لتر ، وعند اعتبار كفاءة المرشحات مساوية إلى /ملغم) ١٤.٤٨(إلى . لتر من المواد الصلبة العالقة/غممل) ١١.٠( علــى ســبيل . مقبولــة علــى أي حــال تظهــر النتــائج المختبريــة بــان خصــائص المــاء الخــام تمتلــك نســبيًا خصــائص وفي نفس الوقت ،تسبب . وهذه حالة جيدة من الجانب الصحي. المثال تكون العكورة ذات مستويات واطئة جدًا مــن قبــل المشــغلين وتســبب الكثيــر مــن المشــاكل ، حيــث يعتقــد المشــغلين بعــدم العكــورة الواطئــة جــدًا إســاءة فهــم إضـافة . الواطئة تسبب طعمـًا غيـر مرغـوب بـه الكدرة.ضرورة إضافة الشب بحجة أن المياه الداخلة قليلة العكورة ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٦ ه وبالتـالي من الممكن أن تعيش فـي هـذه الميـا) cyst giardira( إلى ذلك ، فان بعض األحياء الدقيقة مثل )al-rawi,2000 (....تؤدي إلى العديد من المشاكل الصحية كذلك فان عملية إضافة المواد الكيمياوية ال تـتم بشـكل فعـال بسـبب عـدم الفهـم الـدقيق لميكانيكيـة التخثيـر والتلبيـد واد الصــلبة وعــدم معرفــة أهميــة التخثيــر الكيميــائي، هــذا مــن المحتمــل أن يــؤدي إلــى زيــادة مقاومــة المرشــحات للمــ .العالقة بعبارة أخرى تقل قدرة المرشحات على اإلزالة واالحتفاظ بالمواد الصلبة العالقة كـــذلك مــــن المشــــاكل األخـــرى هــــي تــــرك أحـــواض الترويــــق والترســــيب بـــدون صــــيانة طــــول فتـــرة الدراســــة وتعطــــل .وجود األشنات طافية في أحواض الترسيب ةالقاشطات حيث تم مشاهد المختبريــة بــان ميــاه النهــر والميــاه المعالجــة فيهــا تراكيــز مــن النتــرات تســاعد علــى حــدوث اإلثــراء تظهــر النتــائج تكــون بســبب مــوتِ فــي الوحــداِت الالحقــِة ) nutrient(إن وجــود المــواد المغذيــة ). eutrophication(الغــذائي هـــذه قطـــع. أعلـــى النهـــرفـــي ) impoundment( -بحيـــرة ســـد حديثـــة-تـــأتي ِمـــْن بحيـــرات الخـــزن الطحالـــِب التـــي بجـدران أحـواض الترويـق طافيـة فـي أحـواض الترويـق والترسـيب وكـذلك ملتصـقة بشكل واضحموجودة الطحالِب وبالتـالي سـوف الالحقـِة تنتقل هذه الطحالـب بواسـطة الميـاه لتبلـغ المرشـحات . clariflocculators) (والترسيب مــن النتــائج ارتفــاع تراكيــز كــل مــن المــواد الصــلبة الذائبــة وقــيم كمــا يظهــر .تقلــل مــن كفاءتهــا فــي إزالــة الملوثــات اإليصالية الكهربائية وانخفاض تركيز المواد الصلبة العالقة في بيئة أسفل النهر بسبب تأثير عمليات الخـزن فـي .بحيرة حديثة ط العــدد االحتمــالي متوســ و متوســط العــدد االحتمــالي لبكتريــا القولــونأظهــرت نتــائج معظــم أشــهر الدراســة وجــود عــدد المســتعمرات البكتريولوجيــةونســبة اإلزالــة الكليــة ل%) ١٠٠(وكانــت ونســبة اإلزالــة الكليــة القولونيــة للبكتريــا قيمــة الكلــور المتبقــي حيــث أنطــول فتــرة الدراســة حيــث أن عمليــة التعقــيم تعتبــر كفــوءة جــدًا ،%) ٩٧.٥٧(كانــت )cheremisionof,2002( . مع إرتفاع درجة الحرارةتزداد الحر الرقم الهيدروجيني، القاعدية، العسرة الكلية، الكالسيوم، المغنيسيوم، (كما أظهرت النتائج أن قيم كل من هي ضمن المواصفات ) الكلورايد،المواد الصلبة العالقة، المواد الصلبة الذائبة، الصوديوم، البوتاسيوم والنترات الكبريتات واإليصالية الكهربائية كانت ،الكدرة النتائج بأن قيم تراكيز كل من العراقية والعالمية ، كما أظهرت .أكبر من المواصفات العراقية والعالمية :من النتائج المختبرية يمكن التوصل إلى اإلستنتاجات التالية :اإلستنتاجات ئص النوعية للمياه الداخلة بدت المحطة وكأنها مجرد سلسلة من وحدات مرور المياه غذ لم تتغير الخصا ١ المحطة قيد الدراسة ال تظهر كفاءة اإلزالة المتوقعة تإلى المحطة عن المياه المعالجة كثيرًا، بتعبير آخر، وحدا . للملوثات أن وحدات المحطة المختلفة ال تؤدي عملها بشكل جيد خاصة عند ما تتعامل المحطة مع ماء جيد النوعية -٢ . ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٧ المواصفات القياسية العراقية والدولية يتبين أنها ضمن عتائج الفحوصات المختبرية معند مقارنة ن-٣ المواصفات المحددة لمياه الشرب لذا فأن نوعية مياه الشرب التي يتم تجهيزها من مشروع ماء الرمادي الكبير اإليصالية الكهربائية فكانت فيما عدا قيم تركيز أيون الكبريتات و . تكون جيدة ومطابقة للمواصفات العراقية أعلى من المواصفات العراقية والعالمية كذلك فإن مياه نهر الفرات تعتبر مصدرًا جيدًا للمياه المغذية لمشروع ماء .الرمادي الكبير قطـع. تأتي ِمـْن بحيـرة سـد حديثـة فـي أعلـى النهـر الطحالِب التي وجود تراكيز قليلة من النترات بسبب موتِ -٤ بجــدران أحــواض طافيــة فــي أحــواض الترويــق والترســيب وكــذلك ملتصــقة بشــكل واضــحموجــودة الطحالــِب هــذه . ) الترويق والترسيب من أجل الحصول على نوعية مياه جيدة ، وإلجل تحسين عملية تشـغيل المشـروع تـم :التوصيات والمقترحات :وضع التوصيات التالية إعتمادًا على النتائج المختبرية .جراء دراسات مشابهة على مشاريع معالجة مياه الشرب في المحافظةإ-١ وضـــع وحـــدات قيـــاس وســـيطرة قبـــل وبعـــد وحـــدات المعالجـــة لمعرفـــة معـــدل الجريـــان ،مقـــاييس -٢ .الضغط .عمل ندوات لرفع الوعي البيئي لدى كافة أطياف المجتمع للتنبيه بخطر التلوث، ومعالجته -٣ ياه في المشروع من خالل مراقبة نوعية المياه الخام يوميًا ومعالجتها بما يالئم تطوير عملية معالجة الم -٤ مواصفات مياه الشرب ، من خالل تحديد جرعة الشب والمخثرات بصورة دقيقة في المختبر ،السيطرة على .كميات المياه في وحدات المعالجة، الصيانة الدورية لوحدات المعالجة شيح بحيث يكون التدرج الحبيبي إلقطار حبيبات الرمل ومعامل اإلنتظام وسمك تبديل رمل وحدات التر -٥ . الطبقات حسب المحددات التصميمية القياسية بناء (معالجة المطروحات السائلة على طول نهر الفرات بمختلف أنواعها قبل عملية طرحها في النهر -٦ ).محطات معالجة مياه الصرف الصحي والصناعي مصدر تجهيز المياه لمشاريع معالجة مياه الشرب ) نهر الفرات(ثير المطروحات السائلة الملوثة علىدراسة تأ -٧ . .إجراء صيانة فنية عامة للمشروع لمعالجة العطالت كافة، وتنظيف أحواض الترسيب والترويق -٨ مواد العالقة وبعض دراسة إمكانية منع السيول من دخول مياه نهر الفرات بشكل مباشر لتقليل تركيز ال-٩ . األمالح المغذية األخرى النحاس،والنتريت، ومتطلب (قياس تراكيز معايير أخرى لنوعية المياه لم يتم قياسها في هذا البحث مثل ١٠ لوجود عالقة بينها وبين بعض المواد (toc)وكذلك تركيز المواد العضوية الكلي )cod(األوكسجين الكيميائي .خالل فترة التعقيم بالكلور )thms(المسرطنه مثل ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٨ :المصادر 1 . a h m e d , e . m . a , 1 9 9 5 "e n v i r o n m e n t a l e n gi n e e r i n g", s u l t a n q a b o o s u n . e n g. c o l l . , a l m u s t a k b a l c o . 2 . a l a d a w i , 2 0 0 5 . m . s , "wa t e r s u p p l y e n gi n e e r i n g ", a l e x a n d r i a u n . e n g. c o l l . , a l m a r e e f c o . . 3 a l la yl a , 1 9 7 7 , m . a . , a h m e d , s h . , a n d m i d d l e b r o o k s , e . j . , “ wa t e r s u p p l y e n gi n e e r i n g d e s i gn ” , a n n a r b o r s c i e n c e p u b l i s h e r, in c . 3 . a l r a w i s . m , 2 0 0 0 "tr e a t i n g o f l o w t u r b i d i t y o f ti gr i s r i v e r b y u n c o n v e n t i o n a l f i l t r a t i o n m e t h o d s ". j . r e s . o n e n v i r. &s u s t a i n a b l e d e v e l o p m e n t , vo l . 3 , n o . 1 . 4 a p h a , aw wa , w p c e , 1 9 9 5 " st a n d a r d m e t h o d s f o r t h e e x a m i n a t i o n o f wa t e r a n d wa s t e w a t e r ", 1 7 t h e d . u s a . 5 a rga w. n . , 2 0 0 1 "r e n e w a b l e e n e rgy i n wa t e r a n d wa s t e w a t e r tr e a t m e n t a p p l i c a t i o n s ", n a t i o n a l r e n e w a b l e e n e rgy la b o r a t o r y. 4 . c h e r e m i s i o n o ff n i c h o l a s p, 2 0 0 2 "h a n d b o o k o f w a t e r a n d w a s t e w a t e r t r e a t m e n t a n d t e c h n o l o gi e s ", bu t t e r w o r t h e i n e m a n n p u b l i c a t i o n s . 5 . h t t p : / / w w w. o s t i . go v / b r i d ge . 6 . fo r b e s . e . , 1 9 8 0 "u p r a t i n g wa t e r tr e a t m e n t p l a n t s " . a n a l t e r n a t i v e t o n e w c o n s t r u c t i o n ". j – aw wa . 7 . g u i d e l i n e s f o r d r i n k i n g – wa t e r q u a l i t y) , 2 0 0 4 , t h i r d e d i t i o n , v o l u m e 1 , w h o li b r a r y g e n e v a . 8 . jazrawi, s.f., 1979, “bacterial pollution for one of the agricultural projects in baghdad”, m.sc. thesus, college of science, university of baghdad. 9 . h t t p : / / e n . w i k i p e d i a . o rg/ w i k i / wa t e r 1 0 . la f o u t i n e e . d . 1 9 7 5 , "u p r a t i n g a n d r e d e s i gn o f wa t e r tr e a t m e n t p l a n t s ", p a r t 1 . 1 1 . m i n i s t r y o f m u n i c i p a l i t i e s &p u b l i c wo r k s , r a m a d i d r i n k i n gw a t e r t r e a t m e n t p l a n t a d m i n s t r a t i o n , 2 0 0 8 . 1 2 . p e a v y s . h o w a r d a n d e t a l , 1 9 8 5 "e n v i r o n m e n t a l e n gi n e e r i n g"4 t h e d i t i o n , m c g r a w h i l l . 1 3 . s a f e d r i n k i n g wa t e r. d r i n k i n g wa t e r _ d 7 3 4 1 in s e r t _ e n gl i s h . p d f ) ( u n ic e f w e b s i t e a r t i c l e s ) http://www.unicef.org/specialsession/about/sgrepoprt-pdf/03_safe 1 4 . . st e e l . e w a n d m c gh e e . t. j , 1 9 7 9 "wat e r s u p p ly & s e w e r a g e ', 5 t h e d i t i o n . 1 5 . te b b u t t , t. h . 1 9 9 8 , "p r in c ip le s o f wat e r q u a lit y c o n t r o l", 5 t h e d , br i t i s h li b r a r y, bi d d l e s lt d . 1 6 . va n s t e e n k i s t e . g. c , 1 9 7 5 "c o m p u t e r s i m u l a t i o n o f w a t e r r e s o u r c e s s ys t e m s " p a r t 3 ( w a t e r q u a l i t y) , a m e r i c a n e l s e v i e r p u b l i s h i n g c o m p a n y, in c . – n e w yo r k . ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٤٩ والمواصفة العراقية رقم )٢٠٠٤(لسنة )who(اه الشرب حسب منظمة الصحة العالمية مواصفات مي) ١( جدول رقم ٢٠٠١لسنة )٤١٧( يبين األحياء السكنية التي يغذيها المشروع وموقعها نسبة إلى المشروع) ٢(جدول رقم حوض الترسيب لتحديد كفاءة يوضح نتائج تحليل تجربة عمود الترسيب) أ٣(جدول رقم كفاءة حوض الترسيب لتحسين مع جرعة الشب المثلى يوضح نتائج تحليل تجربة عمود الترسيب) ب٣(جدول رقم ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥٠ صورة جوية لمشروع ماء الرمادي الكبير) ١(رقم شكل يوضح مراحل عملية المعالجة في المشروع) ٢(رقم شكل كل ش لتجربة عمود الترسيب )ات اإلزالة المتساويةمنحني) (أ – ٣(رقم ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥١ ب -٣( شكل رقم )عمود الترسيب(منحنيات اإلزالة المتساوية لجرعة الشب المثلى ) يبين ا;حياء التي يخدمھا المشروع) ٢(صورة رقم مشروع ماء الرمادي ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥٢ مواصفات مياه النهر) ٤(جدول رقم مواصفات مياه المشروع المعالجة) ٥(ول رقم جد ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥٣ )ماء النهر(اإلحصاء الوصفي لخصائص الماء الخام ) ٦(جدول رقم )الشربماء (المعالجاإلحصاء الوصفي لخصائص الماء ) ٧(جدول رقم ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥٤ ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥٥ ٢٠١٠ ٢العدد ٣مجلة القادسية للعلوم الھندسية المجلد ٥٦ شكل رقم (21) يبين تركيز المواد الصلبة العالقة ف��ي وحدات المشروع 0 10 20 30 40 50 60 اء م ب ر ش ال ن زا خ ال ي ض �ر ا ت حا ش ر لم ا ض حو ب سي تر ال ض حو ب وي تر ال ام خ ء ما وحدات المشروع ة لق عا ال بة صل ال اد و لم ز ا كي تر ر) لت م/ لغ ( م al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 79 fpga realization of speech scrambling using spartan-xl electronic platforms abstract: the field programmable gate array (fpga) approach is one of the most recent category, which takes the place in the implementation of most digital signal processing (dsp) applications. it had proved its capability to handle such problems and supports all the necessary needs like scalability, speed, size, cost, and efficiency. in this paper a new circuit design is implemented for speech scrambling with an implemented example using fpga is provided. in this implementation the speech coefficients are evaluated on both the scrambled and the de-scrambled sides. this implementation was achieved using an fpga kit after building the logical circuits on the specified kit that uses the spartan-xl electronic library type implemented using the ise-4.1 software which is one of the latest versions of the xilinx foundation series 2.1i software. key words: security, data hiding, speech scrambling, fpga, spartan xl. ومات الكالم في تنفيذ الية اخفاء المعل) برمجة مصفوفات البوابات المنطقية(استخدام تقنية االلكترونية) spartan-xl(بتطبيقها على رقاقات محمد ناصر الطرفي. د قسم هندسة الحاسبات والبرمجيات كلية الهندسة–الجامعة المستنصرية -:الخالصة أن أتساع الحاجة الى الرقاقات الرقمية ذات السرع العالية و الحجم الصغير و التي تمتلك قابليات عاليـة فـي مجـال عالجة المعلومات أصبح من المسائل الملحة التي تتسايق الشركات العالمية ألثبات قابلياتها في هـذة المجـاالت و مـن هـذة م و التي أثبتت أنها الرائد في fpgaالشركات شركة زايلنكس و التي أثبتت حضور منقطع النظير خاصةة بعد تطويرها لرقاقة .قابليات و أقل الكلفمجال معالجة األشارة الرقمية بأعلى ال في هذا البحث تم تصميم دائرة بأستخدام هذة الرقاقة الغرض منها تغيير ماهية الكالم ليتسنى أخفاء المعلومات الحسية و اليمكن تحديدها أال من خالل الدائرة األخرى التي تقوم بعملية أعادة الكالم الى ما كان عليـة قبـل أجـراء عمليـة أخفـاء .المعلومات dr. mohammed n. al-turfi department of computer and software engineering university of al-mustansirya al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 80 المنتج xilinx foundation 2.1 و هو أحد النسخ المتطورة من برنامج ise4.1 تم تنفيذ التصميم ياستخدام برنامج الـ لقد spartan – xlمن قبل شركة زايلنكس على الرقاقة األلكترونية نوع introduction hiding, scrambling, encrypting, coding…etc are the most important processes now a days since the type of wars is changed from the classical ones with bolts and guns to more effective and higher technology ones that uses information's and bits [hussain,2000]. these great changes lead to change the type of data securing that fits these changes by using highly secured, complicated, large speed processing systems in order to be able to have the best response for such purposes [hussain,2000]. the field programmable gate array (fpga) technology was the remedy that takes the place in the fast electronic devices society and it had proved its fitness for handling tasks specialized with very fast, accurate, complicated processes. where these tasks implemented with an exceptional efforts and costs. this lead to make these electronic kits are the new lead for a brand new branch in the designing of all digital systems specially the ones used for security purposes. the last ten years, all the companies that deals with electronic device productions were in a race with each other’s and time to be the initiative in the fpga production field, because of the new word needs for this type of technology. recently, field programmable gate arrays have enjoyed widespread use due to several advantages related to relatively high gate density, short design cycle, and low cost. they can be used in all applications that currently use small – scale integrated circuits (ssi), medium– scale integrated circuits (msi), large scale integrated circuits (lsi), and programmable logic devices (plds). they also replace mask – programmable gate array (mpgas) in many applications that are limited to 10000 gates and they do not need a very high operational speed.[ hussain,2000] speech is the one of the most important type of data since nearly 90% of direct dealings and direct data exchange is represented by conversations and conferences which leads to secured them as possible specially secret and top – secret ones. since the amount of data in the speech specially for long periods of time is relatively large, then the circuit must have large capabilities and hence more complicated designs for transmitting and receiving the scrambled speech [1,2]. in this paper a new design for a circuit that can perform the speech scrambling on the transmitting and de-scrambling on the receiving sides are dedicated. the circuit operates in a high speed (operating frequency is 1ghz). short processing time and high accuracy (32 bit for the data 4 bytes at a time and five for control bit). receiving data in many ways whether its serial or parallel and produce data in serial or parallel which made the circuit can be used for general purposes easily on both the transmitting and receiving sides. an example and experimental results that has been obtained from the processor is given and shown in this paper with circuit block diagrams to show the data flow and results on the circuit. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 81 fpga developed environments the reason beyond choosing the fpga for the implementation of nearly all the modern digital systems is its fitness for handling the high computationally expensive problems and cover its intensive need for the parallel processing or pipelining [3,4]. therefore among the advantages of fpgas some are: 1. the replacement of the small-scale integrated circuits (ssi) and medium-scale integrated circuits (msi) chips. 2. the availability of parts of the shelf. 3. rapid turn around. 4. low risk. 5. some fpgas have the ability of reprogramming. 6. relatively low cost and flexible design. but its relative long design cycle is a disadvantage because its design process generally requires nine steps as follow : 1. entering the design in the form of schematic, net list, logic expressions, or hdl (hardware descriptive language). 2. simulate the design for functional verification. 3. mapping the design into the fpga architecture. 4. placing and routing the fpga design. 5. extracting the delay parameters of the routed design. 6. re-simulating for time verification. 7. generating the fpga device configuration format. 8. configuring or programming the device. 9. testing the product for undesired functional behavior. this long design cycle force the production companies to face a challengeble problem and hence force them to find suitable solutions. [5, 6, 7] solutions are divided into four categories. the first one is consist of using the schematic approach for designing, which is used if the design elements and the circuit branches are well defined and their functions are specified. the second one is consist of using the very high-speed integrated circuits hardware descriptive languages (vhdl), where this category is used with looping or iterative processes. the third one uses the finite state machine (fsm) which uses with the control circuits, which have small numbers of inputs and outputs. any of the above categories can be merged together to form a new combination for handling new jobs. for example, we can implement a control circuit in an fsm part to control the process flow of a certain function implemented using the schematic approach. the fourth category uses the high level language which is called the system c4 or system c5 [8]. this branch is a wild force pci plug in board with 5-15 processing elements (pes) with a 1mbyte imbedded memory attached to each pe, and other inter connectors like fifo, crossbars, single inline modules data (simd). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 82 this board is installed by its installation software after its placement in the motherboard of the personal computer, where this kind of kits operate on 1,3,5,10,20,33,66 mhz clock frequency with large number of inputs and outputs and wide range of function control and implementation [chan,2000]. speech scrambling one of the most important strategies for data hiding that is used in data security category is speech scrambling. speech scrambling that will be discussed in this paper will consider that 95% of the phone lines uses the 56kbit/sec fax-modem where the speech sample consist of 8 bits and the maximum bit rate of the phone line is 64 kbit/sec. (assuming the last intelligent frequency component in the speech is 4khz. using nyquest rate so we will have 8ksample/sec. with 8bit/sample will lead to have a bit rate of 64kbit/sec.) [gilbert,2003 and shafer,1982]. speech scrambling depends upon the implemented scrambling functions inside the processing circuit because as much as the scrambling function is complex it’s difficult to be broken. but at the same time it will be time consuming and in need for more operations to handle the task which leads to make the circuit in need for more processing power (this means that the design is in need for more electric power and high-speed components with more complex circuit design)[ gilbert,2003 and figueroa ,2003]. in this paper speech scrambling is first performed by reversing the order of the bits of each sample. then the system proceeds to perform the scrambling process on the modified sample. at the end of the process, the data will be ready to be transmitted. on the other side, the data must be re-scrambled in order to reverse the order of the bits of each sample and then retrieve the original sample where the speech data now are the same as the ones at the start of the process. fpga simulation of speech scrambling systems this paper shows a new method for designing an fpga digital circuit for the evaluation of the coefficients of speech scrambling implemented using the ise-4.1 software produced by xilinx company for fpga electronic kit productions which represents one of the most recent updates for the xilinx foundation series 2.1i. therefore the simulation process should pass through four stages as follow. the problem formulation and function establishment represents the first stage. in this stage the general features of the problem are identified in order to specify the needs for the problem solution. in the other hand; the function establishment is very important to specify the necessary equipments and devices for function implementation where the limitations and boundaries are defined. the second stage is represented by over coming the limitations and difficulties in a reasonable way keeping an eye to the over all cost. while the implementation of the function must be optimized as much as possible in order to specify the type of the fpga kit, size, capabilities, frequency ranges, number of inputs and outputs, power consumption, scalability, and compatibility. operating the optimized designed kit represents the third stage. generally in this stage two important problems are appearing, the first one is represented by the timing problem, which is the al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 83 most important. the second one is represented by the production of the undesired results and values through the operating process and the way to get rid of them where most of these values are produced due to the timing problem. the fourth stage is represented by connecting the designed kit to the operating environment and search for its compatibility and the best ways for operating in the presence of other system equipments. therefore it’s preferred to choose the kit type, as near as possible to the type of other system equipment’s in order to reduce the compatibility problems. or if it’s possible and not costly to change the whole system since the fpga kits are relatively of low cost. for the first stage, specifying the scrambling function represents the problem formulation where this function specifies the type of speech processing and the way of dealing with each bit of the speech sample for the second stage, the fpga kit for the implemented design is spartan-xl .the spartanxl 1.8v fpga gives high performance, abundant logic resources, rich features set, all at exceptional low price. this family contains seven members offers density range from 50000 to 600000 system gates with wide operating frequency range (500khz – 2.5ghhz)[8,9], delivering more i/os and other features per dollar than other fpgas by combining advanced process technology with a streamlined architecture based on the proven vertex-e. features include block ram (288 k bit), distributed ram (221k bit), 19 selectable i/o standard, 4 dll (delay locked loop), fast predictable interconnection means that successive design iteration continue to meet timing requirements [chan,2000 and gilbert,2003]. the third stage depending upon the type of application, its operating frequency, its operating speed, and its response time. for example if the system is dealing with speech signal then the highest possible frequency component does not accede 6khz in any way. while in target identification the image verification must be real time and very accurate with a very high response speed for direction changing. or if systems are not in need for high speed and have symmetry in their circuits architecture then these symmetric circuits can be combined in few ones and the operations may be performed in sequence, or else redundant circuits will be built to perform parallel processing or pipe lining to achieve the necessary operating speed the fourth stage is represented by implementing the whole system from its receiving point to its transmitting point since the used kit is more than enough to handle this task from size, speed, accuracy, cost. so; building the whole system on the same kit reduces the compatibility problems to the minimum. demonstrated example in this system we have 5 control bits control the flow of the process. these bits prepare each stage to receive the data from the stage before it whenever the data are ready and the stages are in the best situation to perform the data exchange. when the receiving serial – in – parallel – out shift register finish the reception process, the control circuit signal to the reversal latch to receive the data from the shift register in a reversed mode. now when the data settle in the reversal latch the control circuit resets the shift register and enable the scrambling latch to receive the reversed data and scramble it. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 84 the data at the output may be received in a parallel form or in a serial manner according to te application it self. figure (1) shows the circuit designs. figure (2) shows the circuit-timing diagram and the system output for the input applied to the circuit. table (1) shows the bit stream response of the system from the bit entrance to their outlet. figure (3) shows part of the report prepared by the software gives full details about the kit resources and the amount used by the circuit design. at the de-scrambling side the circuit will descramble the bits in a parallel manner in the de-scrambling latch and they will enter the reversing latch in order to obtain the original speech samples. figure (4) shows the de-scrambling circuit designs. figure (5) shows the circuit-timing diagram and the system output for the input applied to the circuit. table (2) shows the bit stream response of the system from the bit entrance until the circuit obtains the original speech samples. therefore the forward and backward speech scrambling phases can be represented by the flow charts shown in figure (6) & (7) respectively: conclusions this paper is to propose a new circuit design for the implementation and evaluation of speech scrambling systems using the fpga platforms. in this type of designs we are not in need for the wide range of circuit design in which we reduce the cost. and because of the kit wide capabilities high speed, high accuracy, low cost, low power consumption, so the transmitting and receiving circuits may be implemented on the same platform. other advantages is achieved by overcoming the disadvantage of the conventional speech scrambling systems that suffers from, where the data may appears byte by byte (serially) or they may appear in parallel form. this needs no large circuit to handle this task or it needs a global synchronization to keep system accuracy where any simple combinational circuit can handle the job properly. with all what had mentioned above, the high speed circuit can handle several tasks at a time because in many applications the speech bit rate is not in need for very high speed circuits to be 1ghz operating frequency which leads to implement several – in – one tasks. these will reduce the time, place, cost, power, and complexity where the same circuit may occupy many speech channels at a time. references [1] mohammad n.hussain, “speaker recognition based upon phonemes using wavelet packet transform” msc. thesis, university of baghdad, department of electrical engineering, october 2000,. [2] n. rex dixon & thomas b. martin “automatic speech and speaker recognition “ 1989.a volume in the ieee press selected reprint series. [3] l.r.rabiner & r.w. shafer “digital processing of speech signal” book , 1982. [4] lawrence rabiner & biing – hwang juang “fundamentals of speech signals” book, 1993. [5] piyush jamkhandi, amar mukherjee, kunal mukherjee, robert franceschini, school of electrical engineering and computer science, “ parallel h/ws/w architecture for computation of multiwavelet transform using rmf algorithm”. report , july 2003, al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 85 [6] sarin george mathen, thesis, university of kansas, “wavelet transform based adaptive image compression on fpga”. book , june 2000 [7] www.xilinix.com, “spartan-xl 1.8 v fpga family: introduction and ordering information’s”. july 2003, company production catalog. [8] pak k. chan, university of california, “digital design using field programmable gate array”. book , october 2000. [9] john e. gilbert , “coding: theory and applications on fpga”. book , september 2003, [10] miguel figueroa , chris diorio, university of washington , ,”a 200 mhz , 3mw,16-tap mixed –signal fir filter”. company production catalog , september 2003 table (1) the scrambling system bit flow table d at a in pu t circuit reversing and scrambling d at a o ut pu t 10 01 10 01 10 01 10 01 99 01 00 00 00 4o 10 01 10 01 10 01 10 01 99 11 11 11 11 ff 10 01 10 01 10 01 10 01 99 10 11 11 11 b f 10 01 10 01 b it r ev er si ng 10 01 10 01 99 b it sc ra m bl in g 00 00 00 00 o o table (2):the de-scrambling system bit flow table d at a in pu t circuit reversing and scrambling d at a o ut pu t 01 00 00 00 4o 10 01 10 01 10 01 10 01 99 11 11 11 11 ff 10 01 10 01 10 01 10 01 99 10 11 11 11 b f 10 01 10 01 10 01 10 01 99 00 00 00 00 o o b it – d e s cr am bl in g 10 01 10 01 b it – r ev er si ng 10 01 10 01 99 http://www.xilinix.com al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 86 figure (1) the circuit design for speech scrambling figure (2):timing diagram for the i/p & o/p data of the circuit al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 87 figure (3) part of the report that pr epared by the software about the circuit al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 88 figure (4) the circuit design for speech de-scrambling figure (5) timing diagram for the i/p & o/p data of the circuit at the de-scrambling side al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 89 data receiver (mic or file) data processing sampling frequency precision & accuracy is data process finished no yes pass the data to the input shift register 4 byte ,32 bit , serial – in – parallel – out shift register is data input finished yes no shift the data in order to be scrambled parallel bit scrambling to reduce scrambling time pass the data to the output shift register 4 byte ,32 bit , parallel – in –serial – out shift register is data output finished yes no scrambled speech data to the file or speaker end start figure (6) the forward phase of speech scrambling process al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 90 data receiver data preparing for processing is data preparatio n no yes pass the data to the input shift register 4 byte ,32 bit , serial – in – parallel – out shift register is data input finished yes no shift the data in order to be de-scrambled parallel bit de-scrambling to reduce de-scrambling time pass the data to the output shift register 4 byte ,32 bit , parallel – in –serial – out shift register is data output finished yes no original speech data end start figure (7) the backward phase of speech scrambling process 403 forbidden<br> 1 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 62 data compression for dna sequence assist.lec. asaad sumoom daghal technical college-najaf department of technical communication engineering asaadasaad2000@yahoo.com abstract dna sequences making up any organism comprise the basic blueprint of that organism so that understanding and analyzing different genes within sequences has become an extremely important task. biologists are producing huge volumes of dna sequences every day that makes genome sequence database growing exponentially. the databases such as gen-bank represent millions of dna sequences filling many thousands of gigabytes computer storage capacity. hence an efficient algorithm to compress dna sequence is required. in this paper compression algorithm which is called “huffman code tree” is used to code and compress dna sequences. depending upon this algorithm we assigning binary bit codes (0 and 1) for each base (a, t, c, and g). after assigning the bases by bit codes, we determine the code for each base. code for each base is determined by tracing out the path from the root of the tree to the leaf that represents that base. huffman code provides a variable code length. in fact the codes for characters having a higher frequency of occurrence are shorter than those codes for characters having lower frequency. so this algorithm compress dna sequences better than from old method (fixed length) if we assigning 2 bits per base. from analysis the results, average code length (1.62 bits/base) can be achieved using this algorithm. for a higher compression ratio advised to use other compression method with the proposed method such as the learning automata. key words: dna, huffman code, compression الحمض النووي متواليةضغط البيانات ل سموم دغل مدرس مساعد . أسعد نجف / قسم هندسة تقنية االتصاالت–الكلية التقنية الخالصة فهم وتحليل أ األساسي لهذا الكان بحيث لمخططشمل اي حي ي كان ألمتواليات الحمض النووي تشكل علماء األحياء كميات في كل يوم ينتج متواليات أصبحت مهمة هامة للغاية.ال ضم الجينات المختلفة باطراد. قواعد البيانات مثل متزايدةيجعل قاعدة بيانات الجينوم , هذا ما ة م تسلسل الحمض النووي ضخم عدة آالف م إلىالتي تحتاج سعة خز قد تصل بنك الجينات تمثل الماليي م تسلسل الحمض النووي ا الحمض النووي. في هذ سلسلفعالة لضغط ت خوارزميةالكمبيوتر. وبالتالي مطلوب الغيغابايت م سعة mailto:asaadasaad2000@yahoo.com data compression for dna sequence 62 تسلسل الحمض ترميز وضغطشجرة هوفما " يستخدم لرمز سمى "تي تال المستخدمةضغط الخوارزمية البحث . بعد ( a, t, c, g)دة ( لكل قاع1و 0ثناني ) قطعةرمز يتم تأشيرهذه الخوارزمية على النووي. اعتمادا رمز لكل قاعدة ع طريق تتبع المسار م جذر ال إيجاد م. يتتأشير الرموز للقواعد نجد الرمز لكل قاعدة .تمثل تلك القاعدة التي ورقةالالشجرة إلى التي لها تكرار عالي للظهور يكو رموز لشخصيات ال حقيقةرمز متغير. في الطول هوفما يوفر ترميز وارزمية المقترحة تضغط متواليات تمثيلها بطول أقصر م الرموز للحروف التي لها تكرار قليل. لذلك فأ الخ وم تحليل .قطعة لكل قاعدة 6نح استخدمنا إذاالحمض النووي أفضل م الطرقة القديمة)طول ثابت( . للحصول على نسبة الخوارزمية المقترحةيمك انجازه باستخدام بت لكل قاعدة 1626طول رمز النتانج, معدل .مثال التعلم اآللي مع الطريقة المستخدمة أخرىينصح باستخدام طريقة ,ضغط أفضل 1. introduction the compression of dna (deoxyribonucleic acid) sequences is one of the most challenging tasks in the field of data compression. since dna sequences are “the code of life” we expect them to be non-random and to present some regularities. it is natural to try taking advantage of such regularities in order to compactly store the huge dna data bases which are routinely handled by molecular biologists. [2] the amount of dna being extracted from organisms and sequenced is increasing exponentially. this yields two problems: storage and comprehension. despite the prevalence of broadband network connections, there still exists a need for compact representation of data to speed up transmission. transferring a single sequence that is millions of characters long to may take ten to fifteen minutes over a dial up connection. compression of genomic sequence can decrease the storage requirements, and increase the transmission speed. dna sequences are comprised of just four different bases labeled a, t, c, and g (for adenine, thymine, cytosine, and guanine respectively). t pairs with a, and g pairs with c, and can be coded using two bits per base. according to functionality, dna manifests different properties from other kinds of data. standard compression al go ri thm s for text or image files exploit small repeated patterns and contextual similarities to achieve compression. however, repeated patterns in dna sequences are typically much longer and less frequent, so standard compression algorithms perform poorly on dna. the most popular general-purpose encoders of today, such as gzip [ 4 ] , which is based on the lempel-ziv algorithm [5], and bzip2, based on the burrows-wheeler t r a n s f o r m [7], which usually produces more than two bits per base to achieve the un-encoded representation. hence, the quest for efficient dna compression programs started to become popular in the competition-driven c o m m u n i t y of data compression enthusiasts. dna sequences are compressible, s o they are not random. but they are not highly compressible. it is therefore necessary for coding methods to be as efficient as possible. in the context of compression, missing structure will lead to inefficient compression. [3] 2. data compression: in computer science and information theory, data compression or source coding is the process of encoding information using fewer bits (or other informationbearing units) than an un-encoded representation would use, through use specific encoding schemes. compression is useful because it helps reduce the consumption of expensive resources, such as hard disk space or transmission bandwidth. compressed data must be decompressed to be used, and this extra processing may be detrimental to some applications. therefore, the design of data compression schemes therefore involves trade-offs among various factors, including the degree of compression and the computational resources required to compress and uncompress the data. further some compression al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 62 algorithms can introduce distortion in data which are known as lossy compression. lossless compression algorithms usually exploit statistical redundancy in such a way as to represent the sender’s data more concisely without error [6]. lossless compression is possible because most realworld data has statistical redundancy. for example, in english text, the letter “e” is much more common than the letter “z”, and the probability that the letter “q” will be followed by the letter “z” is very small. lossless compression exploits the repeats, palindromes and patterns present in the digital to reduce the over all size. the ratio of the original, uncompressed data file and the compressed file is referred to as the compression ratio. the compression ratio is denoted by equation (1). [1] compression ratio = file compressed theof size file original theof size (1) 3. huffman coding in computer science and information theory, huffman coding is an entropy encoding algorithm used for lossless data compression. the term refers to the use of a variable-length code table for encoding a source symbol (such as a character in a file) where the variable-length code table has been derived in a particular way based on the estimated probability of occurrence for each possible value of the source symbol. it was developed by david a. huffman. huffman coding uses a specific method for choosing the representation for each symbol, resulting in a prefix code (sometimes called "prefix-free codes"), that is, the bit string representing some particular symbol is never a prefix of the bit string representing any other symbol that expresses the most common source symbols using shorter strings of bits than are used for less common source symbols. huffman was able to design the most efficient compression method of this type: no other mapping of individual source symbols to unique strings of bits will produce a smaller average output size when the actual symbol frequencies agree with those used to create the code. a method was later found to design a huffman code in linear time if input probabilities (also known as weights) are sorted. huffman tree generated from the exact frequencies of the text "this is an example of a huffman tree". the frequencies and codes of each character are shown in figure 1 and table 1. encoding the sentence with this code requires 135 bits, as opposed to 288 bits if 36 characters of 8 bits were used [6]. 4. the average code length or weighted length the average number of bits per base (length) is measured according to the following equation (2). [1] i l i iavg pll   1 (2) where lavg= average code length il = code length in bits. ip = histogram probability. we can calculate histogram probability ( ip ) from equation. (3). length sequence length base ip (3) or we can calculate weighted length from equation (4). [8] http://en.wikipedia.org/wiki/variable-length_code http://en.wikipedia.org/wiki/david_a._huffman http://en.wikipedia.org/wiki/prefix_code http://en.wikipedia.org/wiki/linear_time data compression for dna sequence 62    n i i ifilw 1 )()( (4) where iw = weighted extended path (code length) )(il = length of path (number of edges on path) from root to external node labeled i )(if = frequency of occurrences of bases 5. code existing for dna sequence for a dna (a, c, g, t), in classical code method we can represent it in length by 2 bits per base, and assigning as (a=00), (c=01), (g=10), (t=11).this yields when the string a, c ,g, t whose sequence length is 1200, in classical code method ( fixed length) , this requires 2400 bits of space. that’s mean the storage of encoded sequence is almost double its original sequence length [9]. 6. proposed algorithm: the process of proposed algorithm is achieved by constructed huffman tree, and then derived codes from it, that are used to calculate the number of bits in the encoded sequence length. 6.1 structure of huffman tree codes: huffman coding is the based on building a binary tree that holds all characters in source at its leaf nodes, and with there corresponding characters frequencies (probabilities) at the side. the nodes from the original tree are called internal nodes. the special nodes are called external nodes. the following tree shown in figure 2 is extended binary tree. empty circles represent internal nodes and boxes represent external nodes. every internal node consists of exactly 2 children and every external node is a leaf. the tree is built by going through the following steps. [10] 1combine the two lowest frequencies (probabilities) and continue this procedure. 2assign “0” to higher frequency (prob.) and “1” to lower frequency (prob.) of each pair, or vice versa. 3trace the path for each character frequency from lower to upper point. recording the one’s and zeros along the path. 4assign each character (message) codes sequentially from right to left. 6.2 tree of dna sequence {a, c, g, t}: because the dna sequence have only four latter (a, c, g, t), we show that from the figure 2, the number of internal node is (3) and the number of external node is (4). using figure 2 and procedure of huffman code tree, we can built the code of dna sequence and get the results as: (a=1, t=00, c=010, g=011) from the result of code dna by huffman tree we show that the four latter always represented by 7 bits and we can calculate weighted length from equation (4) as: calculation of bits in encoded sequence = 1*f(a)+2*f(t)+3*f(g)+3*f(c). 6.3 construct tree of dna sequence: we can construct dna tree and encoded being code step by step as shown below. (step1) al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 00 (step 2) combining the lowest frequency values and assigns code (step 3) repeat step 2 until the end data compression for dna sequence 01 7. examples and calculations: example 1: given sub sequence: (aataaaataaaacaaaaaaattaaaagaaaccaaagaattaaaaatta…) sequence length = 600. base frequency code a 275 1 t 275 00 c 25 010 g 25 011 from equation (4), number of bits in encoded sequence = 1*f (a) +2*f (t) +3*f (g) +3*f(c) = 1*275 + 2* 275 + 3*25 + 3*25 = 275 + 550 + 75 + 75 = (975 bits) from equation(1): encoded bits ofnumber basesrepresent bits totalofnumber ration compressio  23.1 975 1200   compression ratio in this case (1.23: 1) example 2: given sub sequence: ( ttttcagtgt tagattgctc taattctttg agctgttctc tcagctcctc atatttttct ) sequence length = 60 base frequency code t 30 0 c 13 11 a 9 100 g 8 101 number of bits in encoded sequence = 1*f(t)+2*f(c)+3*f(a)+3*f(g). = 1*30 + 2* 13 + 3*9 + 3*8 = 30+26+27+24 = ( 1 0 7 bits). 1.1214 107 120 ration compressio   compression ratio in this case (1.1214: 1) example3: let us consider the sub sequence: ( aggcgtatgcgatcctgaccatgcaa…) sequence length = 400 base frequency code a 50 1 t 50 01 c 50 000 g 50 001 number of bits in encoded sequence = 1*f (a) +2*f (t) +3*f (g) +3*f(c) = 1*50 + 2* 50 + 3*50 + 3*50 = 50 + 100 + 150 + 150 = (450 bits) 0.8889 450 400 ration compressio  al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 06 in this example (3) the probability (frequency) occurrence of all bases are equally, and that is represent the worst case. so the huffman code method is not effective for compression ratio when the probability occurrences of letter are equally. table 2 shows all results (weight length, average code length and compression ratio) 8. comparison with other dna compressors the most natural benchmark for our algorithms is a comparison with the other algorithms designed to compress dna sequences. unfortunately, such a comparison turned out to be a rather difficult task. the first reason is that the source or executable code of dna compressors is usually not available. the second reason is that the huge space and time requirements of most dna compressors make it difficult (or impossible) to test them on sequences of significant length 9. conclusion: the need for effective dna compression is evident in biological applications where storage and transmission of dna are involved. algorithm using the concept of huffmn tree is proposed to compress dna sequences. the binary trees are used to derive the variable length codes that satisfy the prefix property. since huffman’s code satisfies prefix property, it’s an efficient way to encode and decode dna sequences. using huffman code algorithm, it will be easier to compress dna sequences but it is not efficient when we use alone to get good compression ratio, because the dna sequence is always as pair. this means the likelihood of the occurrence of (a and t) as well as equal and so on c & g. therefore, this affects in compression ratio because the huffman algorithm depends on the occurrence one of the elements with a high probability and the result is a short length of bits and this does not occur in dna sequence. so this is representing the major limitations of using huffman code to compress dna sequence. 10. future work: dna sequences may be repetitive or non repetitive, for this we can take advantage of this property and use another compression techniques such as run length encoding or use another way such as learning automata with proposed algorithm ( binary tree huffman code) 11. references: [1] e. u. scoot, " computer vision and image processing: a practical approach using cvip tools ", prentice hall, inc., 1998 [2] g. manzini and m. rastero “ a simple and fast dna compression” feburuary 17, 2004 [3] h. afify,m.islam and m.abdel wahedl.“dna lossless differential compression algorithm based on similarity of genomic sequence data base.( i j c s i t ) vol 3, no4, august 2011. [ 4 ] j . g a i l l y , m . a d l e r , " g z i p ( g n u z i p ) c o m p r e s s i o n u t i l i t y" , h t t p : / / w w w . g n u . o r g / s o f t w a r e / g z i p / [ 5 ] j . z i v a n d a . l e m p e l , " a u n i v e r s a l a l g o r i t h m f o r s e q u e n t i a l d a t a c o m p r e s s i o n " . i e e e t r a n s i n f o r m a t i o n t h e o r y, v o l . 2 3 , p p . 3 3 7 3 4 3 , 1 9 7 7 [ 6 ] k . h u f f m a n . " d a t a c o m p r e s s i o n a n d h u f f m a n c o d i n g " . h t t p : / / e n . w i k i p e d i a . o r g / w i k i / d a t a c o m p r e s s i o n , h u f f m a n c o d i n g , s e p t . 1 9 9 1 [ 7 ] m . b u r r o w s a n d d . j . w h e e l e r , " a b l o c k s o r t i n g l o s s l e s s d a t a c o m p r e s s i o n a l g o r i t h m s " , t e c h n i c a l r e p o r t 1 2 4 , d i g i t a l s ys t e m r e s e a r c h c e n t e r , 1 9 9 4 . [8] r. rajeswari, a. apparao and r. kiran “ huffbit compress-algorithm to compress dna http://www.gnu.org/soft-ware/gzip/ http://en.wikipedia.org/wiki/ data compression for dna sequence 00 sequences using extended binary trees. jornal of theoretical and applied it, pp.101-106, 2010. [9] s. grumach and f.tahi ,” a new challenge for compression algorithms: genetic sequences”, i.n.r.i.a, recquencourt, bp105, 78153 le chesnay france [10] y.q. shi and h. sun. “image and video compression for multimedia engineering fundamentals, algorithms and standars”. boca raton london new york washington, d.c.2000. table 1 char. freq. code char. freq. code. a 4 010 n 2 0010 e 4 000 o 1 00110 f 3 1101 p 1 10011 h 2 1010 r 1 11000 i 2 1000 s 2 1011 l 1 11001 space 7 111 m 2 0111 t 2 0110 u 1 00111 x 1 10010 table 2 dna sequence length base frequent base probability eq,.(3) code base weight length eq.(4) average code length bits/base eq.(2) compression ratio eq.(1) sub sequence 1 100 a 45 0.45 1 165 1.65 1.212: 1 t 45 0.45 00 c 5 0.05 010 g 5 0.05 011 sub sequence 2 600 a 275 0.4584 0 975 1.6248 1.23: 1 t 275 0.4584 00 c 25 0.0416 010 g 25 0.0416 011 sub sequence 3 400 a 50 0.25 0 450 2.25 0.8889: 1 t 50 0.25 11 c 50 0.25 100 g 50 0.25 101 sub sequence 4 60 a 30 0.5 1 107 1.7833 1.1214:1 c 13 0.2167 01 t 9 0.15 000 g 8 0.1333 001 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 03 figure 1 huffman tree. figure 2 huffman tree codes for dna template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 299 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. segregation of concrete of different types dhia badr ghailan al-mustansiriayah university, civil engineering department, baghdad, iraq. email: dhia.ghailan@uomustansiriyah.edu.iq received on 14 march 2017 accepted on 9 august 2017 abstract: in this work the concrete free falling effect on segregation was investigated. sixteen free falling specimens were tested by the non-destructive ultrasonic test for four types of concrete. in addition, twelve cube specimens were tested to check the accuracy of the ultrasonic test adopted in this study. four types of aggregates (rounded gravel, crushed gravel, 10mm maximum size crushed gravel and porcelain aggregate) were used to study their effect on segregation of free falling concrete from different height. the test results show that no significant effect for the free falling on the compressive strength of concrete for the four types of aggregate and the results of the non-destructive ultrasonic test were of good agreement with those of compression machine test. keywords: segregation, reinforced concrete, free falling, porcelain aggregate, aci, bs, codes of practice, compressive strength. introduction egregation is the separation of one ingredient from another. concrete segregation may be of two types; the isolation of coarse aggregate from plastic mixture, and secondly the separation of grout from the mix for high water content mixtures. [1] concrete is a mixture of various materials. these materials are different in particle size and specific gravity so that they tend to separate from each other. [1] also there are some other parameters affecting segregation such as unsuitable placing and unsuitable vibration. till this moment no one of the certified codes recommended a specific maximum free falling height of concrete to avoid segregation, while there are at least four studies talking about free falling of concrete from large distances without reducing its quality. [2,3,4,5] the main objective of this study is to investigate the effect of free falling of concrete on the compressive strength for heights up to 4m using different types of coarse aggregate. mailto:dhia.ghailan@uomustansiriyah.edu.iq al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 300 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 1. codes of practice the american concrete standards (aci 318-08)[6] and (aci 301-08) do not refer directly to the issue of concrete free falling. the (aci 304r-00)[7] states that there is no restrictions on the vertical drop distance of concrete to the final position, but that its flow must not separate by falling over reinforcement bars, spacers or rods. the aci 336.1[8] states that for free falling height up to 60 ft; concrete not segregate for piers of 3ft in diameter. no significant effect of hitting reinforcement cages on segregation but it may be more effective in small diameter piers for depths more than 65 ft. [5] sometimes a limit is produced for the maximum free falling of concrete to minimize segregation of concrete. inspectors limit that to a distance of 3 to 5 ft and its preferred to be as less as 2 ft. no one of the aci 318-08 and aci 301-08 constraint the free falling distance of concrete. the aci 304r-00 reported that for open clear forms so that the concrete can fall vertically without disturbance; it is preferred not to use hoppers and chutes. however the aci 304r-00 and aci 318-08 recommended pouring concrete at or close to the final depositing place to prevent flowing segregation. the american society of concrete contractors(ascc)[9] refers to the fact that the free falling of concrete is often permitted in concrete works. using some techniques like chutes or making openings in forms may reduce free falling effect, but the use of these techniques unnecessarily may increase coast without improving quality. contractors usually permit free falling of concrete in caissons to depths up to 46 m. core tests for about one hundred points and for a period of thirty years show no significant effect on concrete quality or strength. [9] in 1994, the federal highway administration(fhwa)[5] and for the available tests data concluded that no effect for striking of concrete with reinforcement bars on segregation. in 1999, the fhwa excluded its 25 ft distance of concrete free falling and stated that the concrete is allowed to fall freely for unlimited distances and that the free falling of concrete for distances up to 150 ft and hitting rebar cages directly does not lead to segregation and has no effect on strength. the british standard of building construction code [10] recommended taking a care for concrete falling through rebar cages to prevent the isolating of cement paste from the mix. generally the concrete mixtures contain no less than 300 kg/m 3 of cement. the use of concrete admixtures to reduce water content, which is necessary for workability, may prevent bleeding segregation and other defects. the rate of fine contents may increase to give an adequate cohesion to the mix. [10] the indian code [11] states that concrete handling and conveying must be as soon as possible to prevent segregation. the free falling distance for concrete conveyed by belts or chutes is limited to 5 ft. a steady uniform flow of concrete must be ensured when using chutes with a slop not less than 1:2 vertical to horizontal respectively to prevent separation of ingredients. when the free fall of concrete is likely to happen in conveying process, segregation, splashing, and ingredients loosing must prevented by using down spots and baffle plates. flexible pipes must be used for depositing concrete when the distance of free falling is more than 10 ft. extra vibration may cause segregation. [11] the chinese code of practice in 2013 [12] stated that concrete depositing and compacting must be in a suitable manner and within a suitable period after mixing. special care must be given in case of free falling concrete to prevent segregation and to keep rebar and molds in their positions. the use of vibrators is necessary for good compaction but inappropriate vibration may result in segregation of concrete. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 301 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2. experimental work the type of aggregate is one of the most important parameters affecting segregation of concrete. four types of aggregate were used to study the aggregate type effect. a 1:2:4 mixing proportion by volume were adopted in this work for all types of concrete to investigate the behavior of each type in free falling from different heights. the quantities used for all types of concrete were given in table 1. a concrete mixer of 0.2 m 3 volume was used. the materials were mixed well in a dry state, and then mixing water was added gradually until a homogeneous mix was produced. table 1.materials proportioning concrete type according to aggregate type notation cement (kg/m 3 ) sand (kg/m 3 ) coarse aggregate (kg/m 3 ) water (l/m 3 ) crushed gravel n 304 630 1260 152 rounded gravel r 304 630 1260 152 10 mm max. size crushed gravel s 304 630 1260 152 porcelain aggregate p 304 630 0.76 m 3 (*) 152 (*) equal volume was taken for light weight aggregate 2.1. test setup the mixtures were fallen under the influence of gravity into 235 mm diameter plastic molds of 1m, 2m, 3m, and 4m heights and for each type of concrete. the free falling height was the same of the mold height. the concrete was placed without vibration, fig.1. the specimens of about 0.013m 3 then covered with plastic sheets for the first 24 hrs, and then put in water for 28 days. three 150mm cubes were cast for each type of concrete. table 2 shows the tested specimens notations. the compressive strength of the tested specimens was determined using the non-destructive ultrasonic test; fig.2. the accuracy of the ultrasonic test results were checked against the results of compression machine for the cube samples, and given in table 3. 3. results 3.1. results table 3 illustrates the test results for the compressive strength of the 150mm cubes by two methods while table 4 gives the results for the tested specimens by the ultrasonic test. the relative compressive strength with the free falling height was illustrated in figs.3 to 6 for all types of concrete. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 302 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. fig.1 test setup fig.2 ultrasonic test al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 303 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 2. tested specimens notations table 3. compressive strength of cubes notation free falling height concrete type n1m 1m crushed gravel concrete (max.20mm) n2m 2m n3m 3m n4m 4m r1m 1m rounded gravel concrete (max.20mm) r2m 2m r3m 3m r4m 4m s1m 1m 10mm max. size aggregate concrete s2m 2m s3m 3m s4m 4m p1m 1m light weight aggregate concrete (max.20mm) p2m 2m p3m 3m p4m 4m concrete types ultra sonic test compression machine test time (sec) fcu (mpa) average fcu (mpa) average n1 32 33.58 25.40 47.13 25.43 n2 41.8 18.76 12.58 n3 37.1 23.87 16.58 r1 32 33.58 31.81 42.18 37.48 r2 32.9 31.38 31.91 r3 33.3 30.48 38.36 s1 34 29.02 28.78 26.04 26.16 s2 33.7 29.63 24.71 s3 34.7 27.68 27.73 p1 45.7 15.95 16.08 12.49 11.41 p2 44.7 16.58 10.49 p3 46.1 15.71 11.24 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 304 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 4. compressive strength of tested specimens specimen time (sec)* fcu (mpa) n1m 52.2 15.22 n2m 55.2 13.37 n3m 53.4 14.42 n4m 55.1 13.42 r1m 40.5** (15.5cm) 10.64 r2m 55.1 13.42 r3m 55.6 13.15 r4m 55.2 13.37 s1m 42.2**(13.5cm) 7.63 s2m 63 9.91 s3m 61 10.31 s4m 62.5 10.27 p1m 89.1**(12.5cm) 2.94 p2m 105 6 p3m 78.5 7.74 p4m 74.2 7.50 *direct test (distance of test is 235mm) ** indirect test (distance of test) fig.3 relative compressive strength of crushed aggregate concrete with free falling height al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 305 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. fig.4 relative compressive strength of rounded aggregate concrete with free falling height fig.5 relative compressive strength of (10mm) maximum crushed aggregate concrete with free falling height al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 306 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. fig.6 relative compressive strength of porcelain aggregate concrete with free falling height 3.2. discussion of results in this research, the four types of concrete were tested to study the free falling effect from different heights on segregation. from the results, the following findings were drown: 1the appearance of specimens was generally good but the compressive strength was relatively small because the concrete was cast without vibration. 2in general, the compressive strength of the specimens was slightly increased with the height of free falling, probably because of the additional compaction of free falling process. 3only specimens of light weight (porcelain) aggregate show significant increase in compressive strength of about (55%) for the specimen of 4m falling height in comparison with the 1m, as shown in fig.6. 4the specimens of rounded (5-20mm) gravel aggregate show an increase of about (26%) in compressive strength as shown in fig.4, while the specimens of (10mm) maximum size crushed gravel show a (35%) increase in compressive strength as shown in fig.5 for specimens of 4m falling height in comparison with 1m falling . 5the specimens of (5-20mm) crushed gravel show insignificant decrease of about (11%) in compressive strength for specimens of 4m free falling height in comparison with that of 1m, fig.3. conclusions from the results above, one can conclude that: 1the free falling of concrete from different heights, up to 4m may generally increase the compressive strength of concrete for the aggregate types used in this research, specially for the light weight aggregate concrete due to the additional compaction occurs due to free falling. 2 for the structural elements such as columns and walls of height up to 4m; concrete can be fallen freely into molds without significant effects on compressive strength. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 307 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3the compressive strength of specimens was relatively small probably because that they were not vibrated. vibration may increase the compressive strength significantly. references 1. suryakanta, "what is segregation of concrete and why it happens?", www.civilblog.org, 2017. 2. baker, c. n. and gnaedinger, j. p.,”investigation of the free-fall method of placing high-strength concrete in deep caisson foundations,” 1960 report. 3. turner, c. d., "unconfined free-fall of concrete,” aci journal, dec. 1970, pp. 975-976. 4. litke, s., ”concrete free fall tested in alabama highway department project,” foundation drilling, junejuly 1992, pp.14 -16. 5. adsc-fhwa report on ''the effects of free fall concrete in drilled shafts, ''1994,pp.5. 6. aci committee 318-08, " building code requirements for structural concrete and commentary (318m-8 & 318rm-08),"farmington hills, michigan,2008,pp.77. 7. aci 304r-00,''guide for measuring ,mixing, transporting and placing concrete'', farmington hills, michigan,2000,pp.17. 8. aci 336.1-01 "specification for the construction of drilled piers", farmington hills, michigan,2001,pp.20. 9. american society of concrete contractors (ascc),technical bulletin,december,2002,no.3,pp.1. 10. code of practice for design and construction (bs8004: 1986), part 1, british standards institution, london,1997,pp-128. 11. code of practice for general construction of plain and reinforced concrete for dams and other massive structures, indian standard institute, manak bhavan, 9 bahadur shah – zafar marg, new delhi 110002,p.26. 12. chinese code of practice, "code of practice for structural use of concrete", 2013,pp.152. http://www.civilblog.org/ al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 394 comparison between marshall and superpave mixtures design asst .lecturer israa f. jasim engineering affairs baghdad university alsaadi_esraa@yahoo.com abstract roads in iraq are performing poorly with pavement life much shorter than the expected. the high traffic intensity in terms of commercial vehicles, the serious overloading of trucks and significant variation in daily and seasonal temperature of the pavement have been responsible for early development of distress like rutting, fatigue and thermal cracking on bituminous surfacing. one of the advantages of the marshall mix design method is that the performance of the mixes can be expected for local materials and environmental impact. the superpave mix design method differs from the marshall mix design methods by using performance-based and performance-related criteria to design the proper asphalt mix. this allows a direct relationship to be drawn between the lab and field performance of the asphalt mix. this technology has a tremendous potential to be implemented in iraq, which will pay itself with higher performance and longer lasting roads. hence, there is need to have a comprehensive study comparing the design of bituminous mixes using both superpave and the marshall method of mix design. the main objective of the study is the comparison between traditional marshall design method and the superpave system design method in the wearing course mixes in flexible pavements. this process will be carried out by evaluating the volumetric, mechanical properties and moisture susceptibility. mailto:alsaadi_esraa@yahoo.com israa f. jasim 395 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 key words: super pave mixes, marshall mixes, optimum asphalt content, superpave gyratory compactor, marshall test. nomenelature b◦ = optimum content. b 1 = % of asphalt content at maximum specific gravity. b 2 = % of asphalt content at maximum stability. b 3 =% of asphalt content at 4 % of air voids in total mix. a.c = asphalt content astm = american society for testing and materials. v.f.a = voids filled with asphalt (%) v.m.a = voids in the mineral aggregate (% of bulk volume) a.v = air voids in total mix. esal =equivalent single axle load hma = hot mix asphalt isgc =iraqi superpave gyratory compactor oac =optimum asphalt content scrb =state commission of roads and bridges. shrp = strategic highway research program. introduction virginia has used the marshall method of asphalt mix design for many years. the method subjects an asphalt-aggregate mixture to a specified comp active effort supplied by a dropping mass and uses the void structure of the compacted specimen to determine the proper asphalt content. the method has served users of asphalt hot mix well for several decades, but problems have developed recently because of increased traffic loads. as traffic becomes heavier, the marshall method may not duplicate the kneading action of traffic, and achieving the ultimate purpose, the prediction of mix voids after considerable traffic, becomes more difficult (maupin,1998).. the superpave mix design method differs from the marshall and hveem mix design methods by using performance-based and performance-related criteria to design the proper asphalt mix. this allows a direct relationship to be drawn between the lab and field performance of the asphalt mix [asphalt institute (1996)]. comparison between marshall and superpave mixtures design al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012396 superpave technology as a new design methodology can be rigorously used under varying traffic and environmental conditions. although superpave is recognized as a significant system in the evaluation of asphalt concrete mixes, iraqi agencies continue to use marshall method as a unique mix design method in road projects. accordingly, an investigation is needed to compare analyze and investigate the performance and the properties of superpave and marshall mix design methods. there is international concern and interest in implementing superpave in roads and airport projects to investigate its impact on economic and performance of these projects superpave mix design is based on (1) properties of the asphalt binder and aggregate and (2) volumetric properties of hot mix asphalt (hma). the characteristics of the densification curve obtained during gyratory compaction of (hma) are believed to be related to the strength of the aggregate skeleton [anderson et al. (2002)]. the strength of the aggregate skeleton can give an indication of asphalt mixture strength and, consequently, the expected pavement performance. as such many asphalt technologists believe that superpave gyratory compactor data can be used to evaluate asphalt mixture strength properties. the superpave technology was developed in the united states with proven success. superpave mixes have been widely used by developed countries over the last few years. superpave technology is replacing the marshall method, which was used for asphalt concrete mixture design for almost half a century. the marshall method was based mostly on experience and statistical analysis. the flexible pavement sections designed using the marshall method have had mixed success due to poor understanding of mechanism of failure. the partial success has been mainly due to very thick and uneconomical sections. the roads in iraq are in a highly distressed condition with pavement life much shorter than the expected. a new design methodology, that is more thorough and comprehensive, is required. superpave technology can be rigorously tested under varying traffic and environmental conditions. marshall mix design method bruce marshall, formerly the bituminous engineer with the mississippi state highway department, developed the original concept of the marshall method of designing asphalt pavements. the present form of marshall mix design method originated from an investigation started by the u.s army corps of engineers in 1943. the purpose of marshall method is to determine the optimum asphalt content for a particular blend of aggregates and traffic level .the optimum asphalt content is determined by the ability of a mix to satisfy stability ,flow ,and volumetric properties,(vasavi k. , 2002). five separated smooth plots with percent of the binder content on xaxis and the following on y-axis  unit weight  marshall stability  flow  vma  voids in total mix (va) optimum asphalt content is selected as the average content for maximum specific gravity, maximum stability, and 4% of air voids in the total mix as shown in equation (1) [garber (1993)] .thus, b◦= 3 321 bbb  (1) where: b◦ = optimum content. b 1 = % of asphalt content at maximum specific gravity. b 2 = % of asphalt content at maximum stability. b 3 =% of asphalt content at 4 % of air voids in total mix. israa f. jasim 397 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 superpave mix design method to predict how well an asphalt mix will perform at a project site, mix designers need to be able to simulate in the laboratory the effects of traffic, climate, and construction practice in the field. to do this, the superpave system uses a new, quiet, and easy-to-use method of laboratory compaction the superpave gyratory compactor, developed by the strategic highway research program (shrp). khaled and jason [1998] stated that the optimum asphalt content was determined by compacting and analyzing two specimens at each of the following four asphalt binder contents:  estimated asphalt binder content (obtained previously from the trial blends),  estimated asphalt binder content + 0.5%,  estimated asphalt binder content 0.5%, and  estimated asphalt binder content + 1.0% compaction and volumetric properties are evaluated for the selected blend at the different asphalt binder contents. from these values, graphs of air voids, vma, and vfa are plotted as a function of asphalt content. the design asphalt binder content is established at 4.0 percent air voids, and the other mixture properties are checked. superpave gyratory compactor in order to use superpave system in the comparison process in asphalt concrete mixture, a locally superpave gyratory compactor has been manufactured to assist in the preparation of the required superpave specimens the gyratory compactor is an integral part of the mix design and testing phases of superpave .the gyratory compactor compacts an asphalt specimen by applying a pressure of 600 kpa to the mix while gyration the mould at an angle 1.25o. the height of the specimen is continually monitored, providing the information on density of the mix throughout the compaction cycle. this information is recorded and can be sent to computer, printed, or plotted [traxler electronic laboratory inc. (2001)]. figure 1 shows iraqi superpave gyratory compactor which is manufactured by abbas f. jassim, m.sc student/ highway and transportation engineering in 2005[abbas ((2005)]. materials used in the study materials used in this study are locally available .they are included aggregate, mineral filler, and asphalt cement. asphalt cement one penetration grade (40-50) of asphalt cement is used from daurah refinery .the physical properties and tests of asphalt cement are presented in table 1. aggregates the (crushed) aggregate used in this work is brought from the hot mix plants of ammanat baghdad at (al-tagi). the source of the two aggregates is from alnibaee quarry. to produce the identical and controlled gradation, aggregates are sieved and recombined in the laboratory to prepare the selected gradation, as shown in figure 2 within the specifications requirement of astm [d-3515] for (12.5mm) nominal size. the mid of scrb specifications is followed to select the suitable gradation of the original mix. the gradation is presented in table 2 and described as type iii in scrb (2004).in iraq, this gradation is well recommended by scrb and ammanat baghdad to be used for the purpose of wearing course hma preparation. compared with the superpave classification, the gradation represents arz which is used to prepare the original mix in this study. comparison between marshall and superpave mixtures design al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012398 mineral filler ordinary portland cement (from badoush factory) has been used in this study. the chemical composition and physical properties are shown in table 3. experimental work the main asphalt concrete mixture properties (stability, unit weight, flow, volumetric properties, stiffness, and permanent deformation) are obtained by performing the required laboratory tests. marshall specimen specimen preparation and compaction (marshall specimen) the aggregate is first dried to constant weight at 110 °c, separated into desired size and recombined with mineral filler in order to meet the required gradation for each specimen .the aggregates are heated to a temperature of 175 to 190 °c [kuwait motorway specification (1998)], the compaction moulds assembly and hammer are cleaned and kept pre-heating to a temperature of 100 to 145 °c. the asphalt is heated to temperature of 121 to 138 °c and the requirement amount of first trail of asphalt is added to the heated aggregate and thoroughly mixed. the mix is placed in a mould and compacted with standard number of blows (75) as specified. the samples are taken out of the mould after few minutes using sample extractor. determining the marshall stability and flow of each specimen (marshall specimen) the marshall stability and flow test are performed on each specimen, which is tested for bulk specific gravity, in accordance with procedure described by astm [d1559] for "resistance to plastic flow of bituminous mixtures" using marshall apparatus. in conducting the stability test, the specimen is immersed in bath water at temperature 60 ± 1°cfor a period of 30 minuets .it is then placed in the marshall stability testing machine and loaded at a constant deformation of 5 mm per minute until failure. the total maximum in kn (that causes failure of specimen) is taken as marshall stability. the stability value so obtained is corrected for volume .the total amount of deformation is units of 0.25 mm that occur at maximum load recorded as flow value .the total time between removing the specimen from the bath and the completion of the test should not exceed 30 seconds. in order to calculate the marshall volumetric properties, many procedures and equations are used in determining these properties. superpave specimen preparation of hma mixtures once the aggregate blend is selected and the initial trial asphalt binder content is calculated, the hma mixtures are prepared [fhwa (2004)]. this phase consists of the following main steps: • heating the aggregates and asphalt binder to the mixing temperature (159 ± 3ºc). • mixing both components and short-term age mixture for 4 hours at 135°c. • compaction of the mixture at a temperature of 145 ± 3°c. compaction all specimens are compacted using the superpave gyratory compactor (sgc). in superpave, as with other mixture design procedures, asphalt mixtures are designed using a specific compactive effort. compactive effort is a function of the design number of gyrations, n des . n des is used to vary the compactive effort of the design mixture as a function of israa f. jasim 399 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 climate and traffic level. two other compaction levels are of interest: the initial number of gyrations (n ini ) and maximum number of gyrations (n max ) [fhwa (2004), and yildirim et al. (2000)]. log n ini = 0.45 × log n des (2) log n max = 1.10 × log n des (3) climate is represented by the average design for high air temperature. for baghdad, iraq, it is >44 ºc. selected traffic levels are 10-30 million esals for crushed gravel. for the selected traffic levels, n ini , n des and n max are 9, 135, and 220 respectively. specimens for the volumetric analysis are compacted to n max . optimum asphalt content calculation to calculate the optimum asphalt content, marshall and superpave mix designs are followed as stated in the following articles. marshall mix design the results of marshall tests show almost typical relationships between marshall properties and asphalt content. figure 3 shows the above mentioned relationships for different mixtures. five different percentages (4.0, 4.5, 5.0, 5.5, and 6.0) % of daurah (40-50) asphalt cement are used with ordinary portland cement (filler), and (12.5) mm nominal aggregate size is used for dense mix in accordance with scrb specification (r9), for wearing course [scrb (2003)].. the [scrb (2003)] specification of mix design criteria for heavy traffic roads recommends the following values for surface course, as shown in table 4: the optimum asphalt content (o.a.c) of the various mixes is determined from the following marshall curves; (stability, bulk density, and 4% of air voids) .as previously mentioned in chapter three, the optimum asphalt content of the origin mix is determined to be 4.7 %. superpave mix design the aggregate and asphalt cement used for the superpave level one mix design are the same materials as those used in the marshall mix design. a (0.45) power gradation chart containing each trial blend is displayed in figure 2, which includes the superpave mix design criteria. the criteria are determined depending on a (12.5 mm) nominal aggregate size. climate is represented by the average design for high air temperature. for baghdad, iraq, it is >44 ºc. selected traffic levels are 10-30 million esals for crushed gravel. for the selected traffic levels, n ini , n des and n max are 9, 135, and 220 respectively. specimens for the volumetric analysis are compacted to n max . the estimated volumetric properties of the samples and the criteria used to select the appropriate aggregate blend are also listed in table 5. these criteria are also determined by considering 10-30 million design esals. the estimated volumetric properties found in table 5 for the asphalt mix containing aggregate blend a.r.z at 4.0 percent air voids is used to estimate the optimum asphalt content. this value is determined to be 4.3 percent. to determine the corrected optimum asphalt content, four samples are made at the estimated optimum asphalt content, 3.8 percent, 4.8 percent, and 5.3 percent, asphalt contents. for the samples, the g mm and the average percent of g mm at n .int and n .max are shown in table 6. the volumetric properties of the compacted specimens used to determine the optimum asphalt content are shown in table 5-4. plots showing the properties comparison between marshall and superpave mixtures design al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012400 versus percent asphalt content, at an n .des of 135 gyrations, are shown in figure 4. based on the volumetric analysis, the optimum asphalt content is established at 4.0 percent air voids and is determined to be 4.6 percent. the other volumetric properties are checked to determine if the superpave criteria are met. the estimated properties of the asphalt mix at 4.6 percent asphalt content and the criteria are shown in table 6. as before, the criteria are based on a design in which esals is 10-30 million. the optimum asphalt content of 4.6 percent passes all of the criteria in the superpave manual. conclusions and recommendations 1the estimated asphalt content for the superpave mix design is found to be lower than that if marshall mix design method is used .this indicates that the superpave mix design is more economical. 2role of modified asphalt to improve the asphalt-concrete mixture against rutting by using a trial field section. referances anderson, r.m., turner, p.a., peterson, r.l., mallick, r.b. (2002), "relationship of superpave gyratory compaction properties to hma rutting behavior", national cooperative highway research program report 478, national academy of sciences, washington, dc. url: http://gulliver.trb.org/publications/nchrp/nchrp_rpt_478.pdf asphalt institute, (1996),"mix design methods for asphalt concrete and other hot mix type," manual serial no.2, sixth edition, lexington, ky. astm, (1989)," american society for testing and materials annual book of astm standards", section 4, vol, (04-03). fhwa (2004),"v-superpave mixture design guide" url: http://www.nhi.fhwa.dot.gov./download/material/131053/rm/rml05.pdf garba,r.,(2000),"permanent deformation properties of asphalt mixture ," norwegian university of science and technology ,department of civil and transportation engineering,(nvf) conference . khaled, k.,and jason ,s.,(1998),"a prelemnary evaluation of superpave level one mix design procedure ," department of civil and architectural engineering ,university of wyoming . maupin, g.w. (1998) "compression of several asphalt design methods ", virginia transportation research council. scrb (state commission of roads and bridges), (2003) “hot mix asphalt concrete pavements section r9”, revision of standard specifications for roads and bridges, ministry of housing and construction, department of planning and studies. troxler electronic laboratory, inc., (2001)" specimen preparation in superpave mix design," url: www.traxlerlab.com yildirim, y., solaimanian, m., mcgennis, r. b.,and kennedy,t.w.,(2000), “comparative analysis of volumetric properties for superpave gyratory compactors.” in transportation research record 1712, trb, national research council, washington, dc. http://gulliver.trb.org/publications/nchrp/nchrp_rpt_478.pdf http://www.traxlerlab.com/ israa f. jasim 401 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 table 1 physical properties of asphalt cement tests units penetration grade (40-50) penetration (25°c,100 gm,5 sec) astm d-5 1/10 mm 49 absolute viscosity at 60° c astm d-2171(*) poise 2065 kinematics viscosity at 60° c astm d-2170(*) cst 430 ductility (25°c ,5 cm /min )astm d-113 cm >100 softening point (ring and ball )astm d-36 °c 48 specific gravity at 25° c astm d-70)(*) ….. 1.034 flash point astm d-92 (cleveland open –cup) °c 330 after thin film test penetration (25°c,100 gm,5 sec) astm d-5 1/10 mm 25 ductility (25°c ,5 cm /min |)astm d-113 cm >100 loss in weight (163° c,5 hr ) % 0.12 (*)=the test was conducted in daurah refinery table 2 aggregate selection as original selection no. sieve opening (mm) sieve size specification range (%)* selected gradation (%) 1 19 3/4 100 100 2 12.5 1/2 100-90 95 3 9.5 3/8 76-90 83 4 4.75 no.4 44-74 59 5 2.36 no.8 28-58 43 6 1.18 no.16 ….. 32 7 0.6 no.30 ….. 25 8 0.3 no.50 5-21 16 9 0.15 no.100 ….. 10 10 0.075 no.200 4-10 5 * [scrb 2004] comparison between marshall and superpave mixtures design al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012402 table 3 chemical composition and physical properties of mineral filler *= these tests from the factories table 4 scrb specification of mix design properties s.c.r.b specification limits marshall stability, kn 8 minimum marshall flow, mm 2 – 4 air voids, % 35 voids filled with asphalt , % 65 – 85 voids in mineral aggregate, % 14 minimum table 5 estimated volumetric properties for the asphalt mix estimated mixtures volumetric properties @n des estimated mixtures density properties t ra il a .c % e st im at ed a .c % % a ir v o id s % v m a % v f a g m m @ n = 9 g m m @ n = 2 2 0 4.0 4.3 4.0 14.0 71.4 83.55 96.3 criteria 4.0 14.0 65-75 less than 89% less than 98% chemical composition portland cement * lime (cao) 62.2 sulfuric anhydride (so3) 1.5 magnesia (mgo) 3.7 ferric oxide (fe2o3) 5.3 alumina(al2o3) 4.4 k2o na2o 0.58 loss on ignition (l.o.i) 0.3 i.r 0.48 ca(oh)2 …… sio2 21.54 sio3 …… total 100 apparent specific gravity 3.13 %passing sieve no.200 95 israa f. jasim 403 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 table 6 g mm and percent g mm for trial mixes at n .int , n .des , and n .max . percent g mm percent ac max. specific gravity (g mm ) n .int n .max 3.8 2.49 83.0 96.1 4.3 2.472 84.6 97.5 4.8 2.454 85.0 97.7 5.3 2.436 84.5 98.9 figure 1 iraqi superpave gyratory compactor. comparison between marshall and superpave mixtures design al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012404 0.0 1.0 2.0 3.0 4.0 sieve size ,mm(raized to 0.45 power) 0.0 20.0 40.0 60.0 80.0 100.0 p a s s in g (% ) figure 2 gradation of selected aggregate israa f. jasim 405 al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012 4.0 4.5 5.0 5.5 6.0 60.0 70.0 80.0 90.0 100.0 v f a ( % ) -b figure 3 marshall mix design plots 4.0 4.5 5.0 5.5 6.0 11.5 12.0 12.5 13.0 13.5 14.0 s ta b io li ty ( k n ) -a4.0 4.5 5.0 5.5 6.0 asphalt content (%) 1.0 2.0 3.0 4.0 5.0 a ir v o id s ( % ) -e4.0 4.5 5.0 5.5 6.0 2.28 2.32 2.36 2.40 g b u lk ( g m /c m ) -d3 4.0 4.5 5.0 5.5 6.0 13.0 13.5 14.0 14.5 15.0 15.5 v m a ( % ) -c4.0 4.5 5.0 5.5 6.0 asphalt content (%) 2.40 2.80 3.20 3.60 f lo w ( % ) -fcomparison between marshall and superpave mixtures design al-qadisiya journal for engineering sciences, vol. 5, no. 4, 394-406, year 2012406 3.5 4.0 4.5 5.0 5.5 % asphalt content 70 71 72 73 74 75 % v f a 3.5 4.0 4.5 5.0 5.5 % asphalt content 13.0 13.5 14.0 14.5 15.0 15.5 16.0 % v m a 3.5 4.0 4.5 5.0 5.5 % asphalt content 3.0 3.5 4.0 4.5 5.0 5.5 6.0 % a ir v o id s figure 4 volumetric properties versus asphalt content for superpave level one mix design. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٨ effect of compressive strength and reinforcement ratio on strengthened beam with external steel plate asst. lec. hesham abd al –latef numan civil engineering department, college of engineering al-mustansiriya university, baghdad, iraq abstract: the present study is an experimental comparison between the effect of increasing the compressive strength of the section and increasing the reinforcement ratio on the results of strengthening reinforced concrete beams with external steel plates of constant dimensions. the experimental program consists of testing ten reinforced concrete beams. five of them are without external steel plates to be the original specimens while the other five ones are provided with steel plates of same dimensions glued at the bottom face of the beams. three values of compressive strength (f'c) were used in this study which were (22, 45 and 71mpa) and also three ratios of internal reinforcement (ρ) which were (0.01411, 0.02116 and 0.03445) to investigate their effects on the strengthened beams behavior. the results showed that the cracking load and the ultimate load can be increased up to (150% and 137%) respectively. also, by increasing the section compressive strength all the properties of the strengthened beam can be improved while by increasing the reinforcement ratio the deflection and cracking can be reduced to improve the elastic behavior of the beam.. keywords: strengthened beam, external plate, deflection ductility, restraining. الحديد صفيحة من ب المدعمةالناتئة العتبةعلى ونسبة التسليحالقصوى تاثير قوى الشد الخارجية هشام عبد الطيف نعمان الجامعة المستنصرية كلية الهندسة :الخالصة ئج تقوية الدراسة الحالية عبارة عن مقارنة عملية بين تأثير زيادة مقاومة االنضغاط للمقطع وزيادة نسبة التسليح على نتا خمس . يتكون البرنامج العملي من فحص عشر عتبات خرسانية .العتبات الخرسانية المسلحة باستخدام صفائح فوالذية ثابتة األبعاد al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٤٩ من هذه العتبات غير مزودة بصفائح فوالذية لغرض اتخاذها كنماذج أولية بينما تزود الخمس عتبات األخرى بصفائح فوالذية .إلى األوجه السفلى لهذه العتباتباألبعاد ذاتها تلصق وكذلك ثالث نسب من ) ٢ملم/نت 71و 45، 22(ثالث قيم من مقاومة االنضغاط تم استخدامها في هذه الدراسة وهي .لغرض تقصي تأثيراتها على سلوك العتبات المقواة) 0.03445و 0.02116، 0.01411(التسليح الداخلي وهي وكذلك فإن بزيادة . على التوالي) %137و %150(لحمل األقصى يمكن زيادتهما حتى كشفت النتائج أن حمل التشقق وا مقاومة االنضغاط للمقطع فإن كافة خصائص العتبة المقواة يمكن تحسينها بينما بزيادة نسبة التسليح فإن خاصتي االنحراف . واالتشقق يمكن تقليلهما مما يحسن السلوك المرن للعتبة introduction: an important part of the responsibility of the structural engineer is to select, from many alternatives, the best structural system for the given conditions. the wise choice of a structural system is far more important, in its effect on overall economy and serviceability than refinement in proportioning the individual members (nilson et al. 2003). in structural engineering, the maintenance, repair and upgrading of structures are just as important and technical as the design and construction of new structures. in the case of upgrading this usually involves strengthening of an existing structure to satisfy a higher ultimate load and /or more stringent serviceability requirements (jones et al 1982). one of the more successful methods for strengthening the reinforced concrete structures is "plate bonding technique". investigations into the performance of members strengthened by this technique started in the 1960s. more recently, many researches on plain and reinforced concrete have been carried out. the works of jones et al. (1980), swamy et al. (1987), hamoush and ahmed (1990), oehlers et al. (1998) and kheder et al. (2008) have highlighted a number of features of this technique, some of which can be summarized as: � full composite action can be achieved between a concrete member and a steel plate by the use of suitable epoxy glue. � plating has a considerable reducing effect on both flexural crack width and deflection. the reduction is greater than would be achieved by using additional internal reinforcement equivalent to that of external plate. � where failure of a strengthened reinforced concrete member is by yielding of bonded plate, the ultimate strength can be predicted by using conventional reinforced concrete theory accurately. � this technique can increase the flexural stiffness of the beam at all load stages and consequently reduce deflections at corresponding loads with a significant increase in serviceability. � due to controlling of deflections, cracking and concrete strains, this technique increases the range of the elastic behavior of the strengthened beams. however, despite of the plate bonding technique advantages in field of the reinforced concrete structures, the premature failure trouble is still dominant, as shown in figure 1, and al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٠ must be vanished to attain the technique advantages. reinforced concrete beams strengthened externally by plates bonded to the tension face have been noted to fail in a variety of modes, influenced greatly by the plate thickness. failure modes include the following (nguygen et al 2001): � the flexural dominant mode; characterized by extensive yielding of internal reinforcement and external plate, deep intrusion of flexural cracks and crushing of concrete in the compressive zone. � premature separations of the plate at the concrete–glue–steel interface; initiated from the zone of plate curtailment. � horizontal tearing of concrete cover; initiated at the location of plate curtailment, the interface remains intact, with the crack passing through the concrete below the level of main internal reinforcement and proceeds upwards to the point of loading in a steep vertical ascent (shear mode of failure). a hybrid mode of failure in which there is yielding of internal reinforcement and external plate prior to failure; with actual failure being precipitated by the horizontal tearing of concrete cover below the level of internal reinforcement (flexure, shear mode of failure). aims of study: the aims of this study is to select from two options which one is the best for strengthening reinforced concrete beams using the plate bonding technique. the two investigated options are the effects of increasing the compressive strength of the section and increasing the reinforcement ratio on the strengthened beam behavior, whilst strengthening is done by external steel plate having same dimensions. experimental work: the experimental work consists of testing two groups of beams, the first group contains the original specimens (b1, b2, b3, b4 and b5) while the second group contains their strengthened specimens (sb1, sb2, sb3, sb4 and sb5) respectively. the beams (b1, b2 and b3) and their strengthened specimens have the same reinforcement ratio (ρ = 0.01411) but their compressive strengths are incremented (f'c = 22, 45 and 71mpa) respectively to investigate the compressive strength of section effect on the strengthened beams behavior. the beams (b3, b4 and b5) and their strengthened specimens have the same compressive strength (f'c = 71mpa) but their internal reinforcement ratios are incremented (ρ = 0.01411, 0.02116 and 0.03445) respectively to investigate the reinforcement ratio of section effect on the strengthened beams behavior. ten beams are tested under two point loading up to failure to study their strength and deformation characteristics in addition to the mode of failure and ductility. five of the tested beams al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥١ are without external steel plates to be the original specimens while the other five ones are provided with external steel plates of same dimensions glued at the bottom face of the beams. materials concrete three concrete mixes were used to provide three compressive strengths of (22, 45 and 71 mpa), as shown in table 1. ordinary portland cement type (i) complying with the iraqi standard specification no. 5/1984. the used fine aggregate was natural river sand with fineness modulus (f.m.) of (2.73), bulk specific gravity (s.g.) of (2.64) and sulfate content, (so3%) of (0.31%) by sand weight, which is less than the limit of iraqi standard specification no. 45/1984. the used coarse aggregate is crushed gravel with maximum size of (12mm); the bulk specific gravity (s.g.) of this aggregate is (2.61) and complying with the iraqi standard specification no. 45/1984. for increasing the compressive strength, a superplasticizer (sp) was used to reduce the water content and compensate the associated reduction in workability, is commercially known as (glenium 51) which complies with astm c 469–86. cylinders and prisms for control tests were cast and stored with each beam and then tested when the beam was tested. the mix proportions and the average results of cylinder strength f'c, modulus of rupture fr and elastic modulus ec for all beams are given in table 1: reinforcement two types of reinforcing steel are used in present work, as shown in table 2; steel bars used as internal reinforcement for flexure and shear in all beams and steel plates used as external reinforcement as well as other internal steel bars in the strengthened beams. deformed steel bars of diameter (16, 25mm) are used for the main reinforcement and plain steel bars of diameter (6mm) are used for stirrups. a steel plate with (1.0mm) thickness is used as external reinforcement in the strengthened beams by bonding to the concrete surfaces by epoxy resin of mechanical properties and especially bond strength greater than the concrete tensile strength. details of beams all the beams were with dimensions of (150x250x2500mm), and their spacing of stirrups and the limitations of reinforcement were adopted according to aci code 318–05, as shown in table 3 and figure 2. the shear span (a/d) for all the beams was constant at (4.21) and provided with steel bar stirrups of (2 legs ø6mm at 100mm). for the strengthened specimens (sb1, sb2, sb3, sb4 and al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٢ sb5), external steel plates with dimensions of (100x1x2500mm) were glued at the bottom faces of the beams. casting and curing of beams two steel molds were prepared for casting the specimens; so that two beams were cast at the same time at one day. six cylinders and three prisms were cast with each two beams for observing the concrete mechanical properties. the concrete was poured at (3 layers) and compacted about (2 min) by a vibrating table. after (2 days), the two specimens and their control units were removed from their molds and cured in water containers at a temperature of about (25°c) until the testing age of (28 days). for the strengthened specimens, the external steel plates were glued at the specimens surfaces by the epoxy resin (glue), as shown in figure 2. preparation and testing of beams before testing, the specimens were painted with a white emulsion to aid the detection of cracks. dial gauge with 0.01mm divisions was positioned at the bottom of beam center. all beams were tested under two–point loading, each equal to (1/2) the total applied load from the loading machine. loading was applied in increments of (4kn) to record the deflection. after each (20kn), the load is kept constant until the required readings of crack widths. testing was continued until the beam showed a drop in load carrying capacity with increasing deflection. testing was conducted by using mfl system of hydraulic universal testing machine type epp300, as shown in figure with a maximum capacity of (3000kn). experimental results: the experimental test insisted on cracking load, failure load, deflection, cracks and their characteristics as well as mode of failure. table 4 contains the exhibited values of the above properties. cracking load it is obvious from table 4 that for the original beams (b1, b2 and b3) which represent the compressive strength increment the appearance of first crack was at load having ratio (16, 19 and 31%) of their failure loads, while for the beams (b4 and b5) which represent the reinforcement ratio increment the appearance of first crack was at load having ratio (20 and 15%) of their failure loads respectively. on the other hand, when strengthen all these beams by constant dimensions al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٣ plates the cracking load raised about (8kn) but the ratio of the cracking load at the strengthened beam to original one was decreased in the both cases; with increasing the compressive strength or increasing the reinforcement ratio but with by increasing the reinforcement ratio the decrease was largest as shown in table 5. from the previous demonstration of results it is clear that increasing the compressive strength is better than increase the reinforcement ratio for increasing the ratio of cracking load to failure load and to delay the appearance of the first crack in comparison the beam ultimate strength. failure load the failure load can be raised by increasing the compressive strength or increasing the reinforcement ratio, but from table 4 the results showed that for the beams (b1, b2 and b3) the failure loads were (101, 104 and 106kn) respectively and this mains slight increase in the ultimate strength in comparison with the increase in the compressive strength. while, by comparison between the beams (b3, b4 and b5) which represent the increase in the reinforcement ratio, their failure loads were (106, 176 and 253kn) and reflected the considerable in the ultimate strength. thus, it is concluded that the reinforcement ratio has the greatest effect on improving the ultimate strength of the beam more than the compressive strength. for the strengthened specimens (sb1, sb2 and sb3) the ratio of the strengthened failure load was (1.18, 1.26 and 1.37) respectively and referred to the activity of increasing the compressive strength in improving the failure load through the strengthening by plate bonding technique. in contrast with the compressive strength action; the reinforcement ratio when increased led to reduce the ratio of strengthened failure load as (1.37, 1.28 and 1.17) respectively observed for (sb3, sb4 and sb5) respectively. so that, it is concluded that the compressive strength has the greatest effect on improving the ultimate strength of the strengthened beam more than the reinforcement ratio. deflection from table 4 where the values of deflection were listed; it is noticed that the deflection proportions to the failure load of the beam, therefore, the deflections of (b1, b2 and b3) were smaller than the deflections of (b4 and b5). the strengthening process exhibited a considerable reduction in deflection especially for (sb4 and sb5) in according with the ratio of strengthened failure load to original failure load when this ratio decreases with the increase in the reinforcement ratio as shown in table 5. on the other side, the load-deflection curves in figure 4 clarify the similarity in the strengthened beams behavior to that of the original ones. ductility typically, ductility is calculated by division the value of deflection at failure per the value of deflection at yield condition and this defined as deflection ductility. that is known by decreasing the compressive strength, increasing the reinforcement ratio or increasing the yield strength of the al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٤ reinforcement the ductility will decrease and the reported effect of flexural strengthening with external reinforcement is a reduction in the ductility relative to the original condition (aci committee 440 2002). the results of the present study confirms the previous report because all the strengthened beams exhibited ductility less than that of original specimens and this came from the increase in reinforcement due to the external steel plate, and for the same reason the ductility of (b4 and b5) was (0.65 and 0.67) which is less than (0.78, 0.76 and 0.77) belong to (b1, b2 and b3) respectively cracking cracking was observed by three variables in the present study; crack width (wu), crack height (h) and crack spacing (s) as shown in table 4. the crack spacing is a function of the number of cracks along the beam. it is noticed that number of cracks was the same in all the strengthened beams and almost less by one crack than that of their original beams and that conforms too many previous researches that stated that plate bond technique has a marginal effect on crack spacing. for the crack width; the original beams (b1, b2 and b3) exhibited reduction in the crack width from (1.45mm) to (1.35 and 1.25mm) respectively to reflect the effect of increasing the compressive strength on reduction the crack width, and after this the beams (b4 and b5) exhibited a constant crack width of (1.25mm) with no effect of increasing their reinforcement ratio. all the strengthened beams exhibited a reduction in crack width and reflected the activity of the plate bonding technique in reduction the crack width. for the crack height; the original beams (b1, b2 and b3) exhibited a crack height of (177, 193 and 199mm) respectively to reflect the effect of increasing the compressive strength on raising the crack height, but for the beams (b3, b4 and b5) the crack heights were (199, 195 and 178mm) respectively to reflect the effect of increasing the reinforcement ratio on diminishing the crack height. the strengthened beams (sb1, sb2 and sb3) which have the same exhibited a same crack height about (173mm) and when reinforcement ratio in the beams (sb4 and sb5) the crack height was more diminishing to be less than (173mm) and to reflect a new prove on the activity of the plate bonding technique in restraining the cracking. mode of failure the urgent problem of the plate bonding technique is the concentration of stresses at the plate ends which lead to premature failure and limit the advantages of this technique. extension the external steel plate reduces the concentration stresses at the plate ends so that the steel plates were bonded along the strengthened beams to ensure a desirable failure. thereby, all the beams failed by the same manner as mentioned in table 4 which was flexure mode characterized by developing of cracks coinciding with rapid increase in deflection continued until the drop of the applied load and indicated yielding of reinforcement left residual deformations after releasing of the load as shown in figure 5. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٥ conclusions: 1. increasing the compressive strength is more preferable than increasing the reinforcement ratio for increasing the cracking load of the strengthened beam with external steel plate and with normal concrete strength best controlling on the cracking load can be achieved. 2. the reinforcement ratio has the efficiency for increasing the ultimate strength of the beam more than the compressive strength, but after strengthening; increasing the compressive strength is more preferable than increasing the reinforcement ratio for enhancing the ultimate strength. 3. the plate bonding technique has a control rule in reduction the deflection of the beam, and this reduction can be raised by increasing the reinforcement ratio. 4. there is loss in ductility of the strengthened beam due to the further use of reinforcement and this loss increases with increase the reinforcement ratio. however, the ductility can be restored by increasing the compressive strength of the beams. 5. the plate bonding technique has a restraint effect for reduction the crack width, the crack width and cracks number. 6. in spite of the action of external steel plate on increasing the reinforcement ratio and then decreasing the ductility, but this action enhances the activity of the internal reinforcement for restraining the cracking and reduction the deflection and leads to increase the elastic behavior range of the beam. references 1. nilson, a. h., darwin, d. and dolan, c. w., "design of concrete structures", international edition, 3rd edition, singapore 2003, 771 pp. 2. jones, r., swamy, r. n. and ang, t.h., "under–and over–reinforced beams with glued steel plates", the international journal of cement composites lightweight concrete, v. 4, no. 1, feb. 1982, pp 19–32. 3. jones, r., swamy, r. n., bloxham, j. and bouderbalah, a., "composite behavior of concrete beams with epoxy bonded external reinforcement", the international journal of cement composites, v. 2, no. 2, may. 1980, pp. 91–107. 4. swamy, r. n., jones, r. and bloxham, j., "structural behavior reinforced concrete beams strengthened by epoxy–bonded external plates reinforcement", the structural engineer, v. 65 a, no. 2, feb. 1987, pp. 59–68. 5. hamoush, s. a. and ahmed, s. h., "static strength tests of steel plate strengthened concrete beams", materials and structures, v. 23, no. 134, may. 1990, pp. 116–125. 6. oehlers, d. j., mohamed ali, m. s. and luo, w., "upgrading continuous reinforced concrete beams by gluing steel plates to their tension faces", journal of structural engineering, v. 124, no. 3, mar. 1988, pp. 224–232. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٦ 7. kheder, g. f., al-khafaji, j. m. and ajeel, a. e., "experimental design of external steel plates and study of concrete strength and reinforcement ratio effects on strengthening damaged r.c. beams", comprehensive scientific engineering conference, engineering and development journal, v. 12, no. 1, oct. 2008, pp. 22–44. 8. nguygen, d. m., chan, t. k. and cheong. h. k., "brittle failure and bond development length of cfrp–concrete beams", journal of composites for construction, v. 5, no. 1, feb. 2001, pp. 12–17. 9. sharif, a., al–sulaimani, g. j. and ghaleb, b. n., "strengthening of initially loaded reinforced concrete beams using frp plates", aci structural journal, v. 91, no. 2, mar. 1994, pp. 160–168. 10. aci committee 440, "design and construction of externally bonded frp systems for strengthening concrete structures (aci 440.2r-02)", american concrete institute, farmington hills, mich, 2002, 45 pp. ttaabbllee 11:: mmiixx pprrooppoorrttiioonnss aanndd mmeecchhaanniiccaall pprrooppeerrttiieess ooff ccoonnccrreettee †† ffrr == 00..77((ff''cc)) ((00..55)) ‡‡ eecc == 44770000 ((ff''cc)) ((00..55)) ttaabbllee 22:: pprrooppeerrttiieess ooff rreeiinnffoorrcceemmeenntt †assumed (es). mmiixx mmiixx pprrooppoorrttiioonnss kkgg//mm33 mmeecchhaanniiccaall pprrooppeerrttiieess mmppaa cceemmeenntt ssaanndd ggrraavveell wwaatteerr sspp ff''cc ffrr †† ffrr eecc ‡‡ eecc 11 334455 770000 11112255 222200 –– 2222..00 33..66 33..33 2244220000 2222119955 22 441155 558811 11009966 118855 44..11 4455..00 66..22 44..77 3322995544 3311552288 33 556600 663355 11008855 115500 88..44 7711..77 88..11 55..99 4400550000 3399779988 rreeiinnffoorrcceemmeenntt bbaarr ddiiaammeetteerr ((øø)) mmmm ppllaattee tthhiicckknneessss ((tt)) mmmm mmoodduulluuss ooff eellaassttiicciittyy ((eess)) ggppaa yyiieelldd ssttrreessss ((ffyy)) mmppaa uullttiimmaattee ssttrreessss ((ffuu)) mmppaa sstteeeell bbaarr 66 ppllaaiinn - 220000 †† 338833 554455 1166 ddeeffoorrmmeedd - 220000 †† 551188 663355 2255 ddeeffoorrmmeedd - 220000 †† 444488 770099 sstteeeell ppllaattee - 11..00 220000 †† 228800 334477 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٧ ttaabbllee 33:: ddeettaaiillss ooff bbeeaammss ttaabbllee 44:: rreessuullttss ooff tteesstt bbeeaamm ccoommpprreessssiivv ee ssttrreennggtthh ((ff''cc)) mmppaa iinntteerrnnaall sstteeeell bbaarrss mmmm22 eexxtteerrnnaall sstteeeell ppllaattee mmmm22 rreeiinnffoorrcciinngg rraattiioo ((ρρ)) %% uuppppeerr lliimmiitt ((ρρmmaaxx)) %% lloowweerr lliimmiitt ((ρρmmiinn)) %% bb11 2222 440022..1122 - 11..441111 11..664477 00..227700 ssbb11 2222 402.12 110000 1.555 11..664477 00..227700 bb22 4455 402.12 - 1.411 22..994433 00..332244 ssbb22 4455 402.12 110000 1.555 22..994433 00..332244 bb33 7711 402.12 - 1.411 44..006644 00..440077 ssbb33 7711 402.12 110000 1.555 44..006644 00..440077 bb44 7711 660033..1188 - 22..111166 44..006644 00..440077 ssbb44 7711 660033..1188 110000 22..226600 44..006644 00..440077 bb55 7711 998811..7755 - 33..444455 55..001133 00..447700 ssbb55 7711 998811..7755 110000 33..661111 55..001133 00..447700 bbeeaamm ccrraacckkiinngg llooaadd ((ppccrr)) kknn ffaaiilluurree llooaadd ((ppuu)) kknn ddeefflleeccttiioo nn aatt yyiieelldd ((∆∆yy)) mmmm ddeefflleeccttiioo nn aatt ffaaiilluurree ((∆∆uu)) mmmm ddeefflleeccttiioo nn dduuccttiilliittyy ((∆∆uu// ∆∆yy)) mmmm ccrraacckk wwiiddtthh ((wwuu)) mmmm ccrraacckk hheeiigghhtt ((hh)) mmmm ccrraacckk ssppaacciinngg ((ss)) mmmm mmooddee ooff ffaaiilluurree bb11 1166 110011 1111..4400 1188..8866 11..6655 11..4455 117777 8833 fflleexxuurree ssbb11 2244 119 1144..6677 18.87 11..2299 11..2200 117733 8833 fflleexxuurree bb22 2200 104 1122..1144 21.34 11..7766 11..3355 119933 8800 fflleexxuurree ssbb22 2288 131 1155..3355 20.43 11..3333 11..2200 117733 8833 fflleexxuurree bb33 3333 106 1133..2211 24.27 11..8844 11..2255 119999 7777 fflleexxuurree ssbb33 4422 145 1177..1133 24.10 11..4411 11..1155 117733 8833 fflleexxuurree bb44 3366 117766 1188..0077 4400..2222 22..2233 11..2255 119955 7788 fflleexxuurree ssbb44 4444 222266 1177..2288 2255..3366 11..4466 11..1155 117711 8833 fflleexxuurree bb55 3388 225533 1188..8855 4411..6666 22..2211 11..2255 117788 8811 fflleexxuurree ssbb55 4466 229955 1177..5533 2266..0011 11..4488 11..1155 116600 8833 fflleexxuurree al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٨ ttaabbllee 55:: rraattiiooss ooff ssttrreennggtthheenneedd ttoo oorriiggiinnaall bbeeaammss pprrooppeerrttiieess a) plate debonding b) ripping off concrete cover figure 1: premature failure hazards (sharif 1994) bbeeaammss ccrraacckkiinngg llooaadd ((ppccrr)) ffaaiilluurree llooaadd ((ppuu)) ddeefflleeccttiioo nn aatt ffaaiilluurree ((∆∆uu)) ddeefflleeccttiioo nn dduuccttiilliittyy ((∆∆uu// ∆∆yy)) ssbb11//bb 11 11..5500 11..1188 11..0000 00..7788 ssbb22//bb 22 11..4400 1.26 0.96 00..7766 ssbb33//bb 33 11..2277 1.37 0.99 00..7777 ssbb44//bb 44 11..2222 1.28 0.63 00..6655 ssbb55//bb 55 11..2211 11..1177 00..6622 00..6677 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٥٩ 250mm 190mm p ø6mm 800mm 800mm 800mm 2500mm main reinforcement ø16 or ø25mm 150mm 250mm 190mm 800mm 800mm 800mm 2500mm p ø6mm external steel plate 100x1x2500mm main reinforcement ø16 or ø25mm glued steel plate 100x1mm 100mm 150mm aa)) oorriiggiinnaall bbeeaammss bb)) ssttrreennggtthheenneedd bbeeaammss figure 2: details of beams figure 3: testing machine . al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 ١٦٠ 0 5 10 15 20 25 30 35 40 45 50 deflection (mm) 0 25 50 75 100 125 150 175 200 225 250 275 300 l o ad ( kn ) b1 sb1 0 5 10 15 20 25 30 35 40 45 50 deflection (mm) 0 25 50 75 100 125 150 175 200 225 250 275 300 l o ad ( kn ) b2 sb2 0 5 10 15 20 25 30 35 40 45 50 deflection (mm) 0 25 50 75 100 125 150 175 200 225 250 275 300 l o ad ( kn ) b3 sb3 aa)) ssppeecciimmeennss wwiitthh iinnccrreemmeenntteedd ccoommpprreessssiivvee ssttrreennggtthh 0 5 10 15 20 25 30 35 40 45 50 deflection (mm) 0 25 50 75 100 125 150 175 200 225 250 275 300 l o ad ( kn ) b3 sb3 0 5 10 15 20 25 30 35 40 45 50 deflection (mm) 0 25 50 75 100 125 150 175 200 225 250 275 300 l o ad ( kn ) b4 sb4 0 5 10 15 20 25 30 35 40 45 50 deflection (mm) 0 25 50 75 100 125 150 175 200 225 250 275 300 l o ad ( kn ) b5 sb5 bb)) ssppeecciimmeennss wwiitthh iinnccrreemmeenntteedd rreeiinnffoorrcceemmeenntt rraattiioo ffiigguurree 44:: llooaadd--ddeefflleeccttiioonn ccuurrvvee ooff tthhee tteesstteess bbeeaammss figure 5: deformation of beam after testing 4-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 new wave of cad systems and its application in design ass. lecturer mahmoud a .hassan al-qadisiyah university college of engineering hasaaneng@yahoo.com abstract this paper provides some lighting needed for the implementation of the new wave of cad systems with emphasis on a general application as well as advanced. it is known that a computational approach is used in both design and education so step-by-step examples are introduced. although the cad systems are available but it needs a sound knowledge of many subjects such that: strength of materials and machine design. this work depends on the torsion theory but the input geometry was done inside the solidworks environment. the proper use of the cad tool needs to start from a published case and construct many models in order to reach the final one. the process was done by exporting the geometry to other sophisticated engineering tools: ansys the adequacy of the obtained results was obtained by comparing with the theoretical data. complex cases in both geometry and materials properties like plasticity are presented. combining these systems with the teaching subjects deepens the engineering knowledge in the design and education. keywords: cad systems, solidworks, ansys, design. –ة . . . . . . .. . al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 nomenclature eq equivalent stress (n/m 2) xy yz zx normal stresses on the axises (n/m 2) xy yz zx: normal shear on the axises (n/m2) : principal stresses (n/m2)231 ø : shear strain : angle of rotation (rad) r: radius of shaft (m) l: length of the shaft (m) introduction the simplicity of the new cad systems and its high advanced simulation in much practical application make these systems to be an engineering design tool. although they depend on the finite element method (fem) as background for solution they can be used with minimum knowledge of the method. the theory of the fem stands behind the stage to enable the domination of the engineering sense. the direct link between the cad geometry and the finite element package meshing and analysis is a powerful step in design. the output graphic contours give a very good indication to modify or accept the design liking the geometry from cad system according to (solid work2007) with the high level of the work like (ansys ll 2009)is the key for many engineering analysis stress criteria the criteria of failure of the design like maximum acceptable deformation, minimum natural frequency and maximum stress level are our indications in designing a component. the stress criteria are the essential player. since the yield stress taken from stress-strain curve can be compared directly to the equivalent stress taken from the stress criteria, a safety factor of the whole component immediately appears. many useful books likes them of (george e.dieter, 1988) linked the materials properties the best stress criterion in the metal design is the von mises. it can be calculated from the state of stresses at any point as: (1) or from the principal stresses as: (2) assuming the material behaves with direct relation between the stress and the strain as in the figure( 1), the only material parameters we need to input are the modulus of elasticity and the poisson's ratio. 3-d torsion when a beam or shaft subjected to twisting moment (torque), the torsion is the stresses of that load. the main features of the torsion problem are the shear stresses, the angle of rotation and the angle of twist. so, the 3-d stress analysis is the general procedure to find out the real response of the beam. there are many direct stress formula to calculate the torsion but for uniform cross-section. the use of )(*3])()()[(*5.0 222222 zxyzxyxzzyyxeq ])()()[(*5.0 213 2 32 2 21eq al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 torsion machine test monitors the angle of twist and other parameters but it is limited as it is a lab work. a practical examples of torsion are demonstrated here as a 3-d stress analysis. the book by (paul m. kurowisky 2005) given many useful examples but it needs more advance approach for engineering problems torsion of beam box four beams each of square cross section of 150 inches in length constructing a beam box of 1500 inches and a thickness of 3 inches. the torque applied is 300 lb.inches figure( 2) shows the geometry of the beam box. a good study of torsional behavior of rectangular hollow section by (daniel j ridley-ellis, john s owen & gwynne davies, 2002) the mesh of the box beam is shown in figure (3) the shear stresses are shown in figure (4) figure (5) shows the total deformations of the model the angle of rotation is given by (3))/2(sin 1 rs the relation between angle of twist and angle of rotation is taken from the strength of material subject lr / (4) r.s. khurmi,2010). where s is the total deformation, r and l as shown in the figure (6) bar of triangular cross-section the sketch of 300mm cantilever bar cross-section is shown in figure (7) the mesh of the this bar is shown in figure(8) the steel bar was subjected to a torque of 2mn.mm the equivalent stresses are shown in figure (9) elastoplastic analysis in elastoplastic analysis, we have to introduce the stress-strain curve, this analysis is an advanced tool which need a special treatment books of (timoshenko, 1983) deals with the case of exceeding the elastic limit the bilinear isotropic hardening type of plasticity was considered to cantilever bar as shown in figure 10 . the plastic strain are shown in figure 11 discussion of resuls the stress analysis tool used is claimed to be aimed to students and designers. it is supposed to help during the modeling work and not to be used as a final calculations tool. this work shows that this is the case. the main advantage in this software is that it is very easy to use. the modeling is very fast, although the solving time can be very long, especially when using result convergence. to get the exact values of the stresses it is shown that one need to use the result out of analytic case with as in the case of the torsion of the box beam. changing the cross-section area of the beam to another shape is a straight forwards task as in the torsion of triangular cross-section beam. during the early modeling work it is therefore always necessary to use a simple start. when students use the analysis tool to get a hint if the model works, the exact published values are so al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 interesting to get out of modeling. it is shown here that the software gives very good results when it comes to non-linear analysis. the problem of plasticity could be analyzed by introducing the real stress-strain curve or even by using an approximate curve as the bilinear isotropic curve used with the cantilever bar. there is one remark with this software. one cannot control the real mesh size, only the relative size. it is a good custom to start with the default mesh of the software then refining the mesh and checking the results until convergence specially with complicated shape models. conclusion the method presented in this paper makes it possible to compute the torsion parameters without of any control of elements or nodes. importing of complex geometry from the cad package can be performed immediately. it has lots of automation for applying complex, realistic load and boundary conditions easily. there is no limit of the applications of these cad systems in design. the practical importance of the procedure lies in the simplicity and integrity references [1] george e. dieter, mechanical metallurgy, 3rd edition, mcgraw-hill company, 1988 [2] paul m. kurowisky, engineering analysis with cosmos work professional, sdc publications, 2005 [3] daniel j ridley-ellis, john s owen & gwynne davies, theoretical and measured torsional behaviors of rectangular hollow sections, proceedings of the international offshore and polar engineering conference, japan, 2002 [4] timoshenko, strength of materials, 3rd edition, krieger publications, 1983 [5] r.s. khurmi, strength materials, 23editionm, s. chand and company ltd, 2010 [6] ansys workbench version 11 documentation [7] solidworks2007 documentation. fig. (1) elastic and elastoplastic stress-strain curve al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (2) the beam box fig. (3) mesh of the beam box al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (4) the shear stresses in the x-z plane fig. (5) the total deformation of the beam box al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.(6) the geometric parameters of a shaft under torque fig. (7) cross-section of a the bar fig. (8) mesh of the bar al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.(9) von-mises stresses along the bar fig. (10) the elastoplastic stress-strain curve fig. (11) the plastic stain of the bar تخمين الإسهامات لقبعة مجموعة ركائز مخترقة تربة طينية مشبعة ٢٠١١ ٣ العدد ٤ المجلد مجلة القادسية للعلوم الهندسية تربة طينية مشبعة تخترقركائزمجموعة اإلسهامات لقبعة تخمين ليث جواد عزيز.د جامعة الكوفة /كلية الهندسة/ القسم المدني :لخالصةا ـ نتيجة ألهمية ة المقامـة علـى التـرب ذات مشاريع المنشاءات المائية وأسس الخزانات األرضية و األبني مدىمن خالل توضيح ، المالئم لكل منشأ األساس اختيار نوع إمكانية في العراق، العمل الحالي وفر المشاكل ، بمعنى )saturated clay( بة الطينية المشبعة التر توفرها قبعة الركائز في حالةأناإلسهامات التي يمكن تلكتعملو )contact with ground( قبعة الركائز عندما تكون بتماس مع سطح التربة آخر المقارنة بين أو عنـدما ال يـتم إدخالهـا ( عندما ال تجلس على سطح التربـة و )pile raft(ساس حصيري أالقبعة ك انجزت عندما األسس بين نوعين المقارنات. )pile group ( تكون منسساأل و في هذه الحالة )بالحسابات very(مثل الطين الرخو جداً ) shear strength ( واطئة مقاومة قصية( حالة الضعيفة الفي التربة تكون soft clay ((في حالة كون التربة قوية كذلكو )ذات مقــاومة قصية عاليـــة مثل الطيــن الصلد .))stiff clay( اسيأو الق )load-settlement curve( النزول -نوعي األسس تمــت باستخـــراج منحني الحملل االستقرارية لعدة قيم من (plaxis finite element program)باستخدام برنامج العناصر المحدد بالكسز و لكل نوع وألنـواع ) l/b= 0.25, 0.5, 0.75, 1.0, 2.0 and 3.0( عرض قبعـة الركـائز إلى الركائزطولنسبة .)su=20,30,57.5,112.5 and 150 kpa ( مساوية إلىمختلفة من الترب الطينية التي تملك مقاومة قص التحليل للنتائج المستخرجة لحالة تربة طينية مشبعة و رخوة جداً وعندما يكون الموديل يملك نـسبة طـوال أظهـر أن منحنـي ) l/b=2.0(إلى ) l/b=0.25( من تتراوح (b) إلى عرض قبعة الركائز(l)الركيز و (pile raft) مـن حالـة أعلىذو ميل ) pile group( اإلزاحة ألساس من نوع-الحمل تكـون اخطـر ) pile raft( أن حالة بمعنى أخر) pile raft(بالتالي يحمل حمل اكبر من المنحني ألساس هذا ) l/b=3.0(وان كال المنحنيين سينطبقان عندما تكون النسبة ) pile group(من ناحية النزول لحالة كـون ي) l/b=3.0(إلـى حالـة ) l/b=0.25( لجميع أطوال الركائز من حالة من جهة و من جهة أخرى من ناحية االسـتقرارية لحالـة ) pile group(هو األفضل من أساس نوع ) pile raft (األساس من نوع ).su=150 kpa(قاسيالطين ال التربة الطينية ، (pile raft)األسس الحصيرية مع الركائز ، (pile cap) قبعة الركائز:كلمات االستدالل (plaxis)برنامج بالكسز، المشبعة ٣٤ estimation of the contributions of pile group cap into saturated clay soil dr. laith jawad aziz civil dep./engineering college/kufa university abstract: due to the importance of the hydraulic structures, sub-surface storage and the building on the problematic soil in iraq, this work presents the methods for choosing the suitable footing (the behavior of a pile cap embedded into saturated cohesive soil), in other words, the comparison between pile cap when it contact with ground surface (pile cap as a raft footing) and it not contact with ground surface ( the resistance of the pile cap is negligible in calculation) such as pile group. the comparisons between two type footings are performed when the soil is very soft (low shear strength) and also when the soil is stiff (high strength). the stability of two types of footing is analyzed in terms vertical load and the generated displacement by using plaxis program. the computer program uses a finite element technique to solve the three dimensional problems of variations in the ratio between pile length and cap width (l/b= 0.25, 0.5, 0.75, 1.0, 2.0 and 3.0 ) and to simulate the effects of the different types of cohesive soil which has shear strength equal to (su=20,30,57.5,112.5 and 150 kpa). the analysis of the results of the very soft clay soil indicates when the model tests at ratios from (l/b=0.25) to (l/b=2.0), the load – displacement curve for pile group footing is steeper than the curve of the pile raft, this leads to high value of the resistance of the soil for pile group. in other words, the case of pile raft into very soft clay is more dangerous than the pile group. for model tests with (l/b= 3.0), the curves for pile group and pile raft footing are coincided with themselves at any load. the stability of pile raft in soil with ratios from (l/b=0.25) to (l/b=3.0) is high than for pile group embedded into very stiff clay soil. : المقدمة-١ ة شائية ذات مقاطع دائري ارة عن أعضاء إن ة أوالرآائز عب مستطيلة تعمل على نقل الحمل من طبقات الترب السطحية الضعيفة إلى طبقات التربة البعيدة عن سطح األرض والتي تمتاز بكونها قوية، وهي أما أن تكون ، وفي معظم الحــاالت الرآائز )timber (أو الخشب ) steel( الحديد أو (concrete) مصنوعة من الخرسانة pile(قبعة الرآائز ، )٥((cap) تربط مع بعضها البعض بقبعة )groups(تكون مستخدمة على شكل مجاميع cap ( يمكن أن تكون بتماس مع سطــح التربة)contact with ground(ك القبعة أما تكون تحمل جزء و تل أن وأ (1a) و آما بالشكل (raft foundation )ساس حصيريقبعة تعمل آأ و في هذه الحالة الحمل المنشأمن أطوال أنتحمل أي جزء من الحمل المسلط و في هذه الحالة نالحظ ال أنهاالقبعة تهمل في الحسابات و تعتبر ـذا النـــوع من األسـس ي (l1) الرآائز في الحالة األولى أطوال يكون اآبر من (l2)الرآائز ـ وان هـ سمــى ب )pile group( و المشاهد بالشكل (1b) أو تحمل القبعة هو آون التربة السطحية ضعيفة إهمال و السبب في ة لالنجراف ا في الخزانات األرضية و و التآآلقابل ا مالحظ بالشكل آم رة تشغيلها و آم ، )1c ( خالل فت و لكن بالحقيقة و نتيجة (pile raft)س من نوع آأسا آشكل خارجيبمعنى أخر الخزانات األرضية يتم تنفيذها pile ( و األساس يكون من نوع لكون أن المنشأ مائي فان تأثير القبعة ال يتم إدخاله بالحسابات group()١(. ذات مشاآل الواقعة أسفل األساس تكونتربةآون الفي إهمال تحمل القبعة السبب في بعض األحيان، (problematic soil)) في الشكل نشاهد هذه الحالة أن و يمكن )تربة جبسية او تربة انتفاخية(1d) فالترب ، الترب الجبسية فتمتاز بخاصية أمااالنتفاخية ستسلط ضغط انتفاخي عالي على األساس يؤدي إلى تكسره تلك الترب و آذلك نحميه منأ من نحمي المنشأنو من اجل ،)التربة تفقد مقاومتها عند التبليل (االنهيارية و أرصفة السفن و الموضحة بالشكل آما في المنشآت المائيةتسرب الماء العالي فأننا نقوم برفع قبعة الرآائز و (1e))٢(. :الهدف من البحث -٢ ٣٥ pile ( والنوع اآلخر من األسس) pile raft(المقارنة بين نوع األساس هدف الدراسة تتلخص في group( تم و دت ولعدة أنواع من الترب ثابتة)l/b ( نسبة طول رآيزة إلى عرض قبعة رآائزما تكونعن shear(ذات مقاومة قصية ن تربة تتراوح م وتلك األنواع من الترب ) saturated clay(الطينية المشبعة strength ( واطئة آالطين الرخو جدًا)very soft clay (مة قصية عالية ذات مقاوةترب إلى)very stiff clay ( النزول إيجاد منحني الحملبوتلك المقارنة تكون) (load-settlement curve الي إيجاد وبالت تتحمل جزء من الحمل المسلط على المنشأ عندما تكون تلك القبعة ) pile cap(مقدار ما تتحمل قبعة الرآائز )pile raft ( ملة في الحسابات وعندما تكون تلك القبعــة مه)pile group ( نوع األساس بمعنى آخر معرفــة في آذلك و) المنشآت المائية أو الخزانات األرضية أو الترب ذات المشاآل ( في حالة آون التربة ضعيفة األفضل . ثابتة(l/b)حالة آون التربة قوية عندما تكون نسبة إهمال قابلية تحمل األساس ()pile group((l2)ـــس أطوال الرآائز في أستوضح أن (1b)و (1a) األشكال اعتبار أن قبعة الرآائز هي أساس إذا تم () pile raft( (l1) تكون اآبر من أطوال الرآائز في حالة )الضحل bulb of) خط اإلجهاد موقعزة و ر االعتبار العالقة بين طول الرآي بنظيقترح األخذ ، لذلك البحث )حصيري stress)ة ، فع د رآائز طويل اطع مع الرآائز أي ان الرآائز ستقاوم ذلك (l/b)ن ان خط اإلجهاد يتق رة ف آبي بنظر االعتبار األخذ عند ( و عند رآائز قصيرة (2a)بالشكل اإلجهاد الذي يحصل داخل التربة و آما مالحظ عدم أو وجود أنا يعني مجموعة الرآائز وهذ أسفل سيقع ) bulb of stress (اإلجهاد فان خط ) تحمل القبعة الشكل و أن الفشل يكون بشكل إسفين متآلف من الرآائز و القبعة و آما ب وجود الرآائز سيكون على حد سواء (2b))١٢( . :بحوث السابقة ال-٣ و آاألتي ) piled raft(يرية صعدد من الباحثين حول العالم قاموا بدراسة األبنية المنشأة على أسس الرآائز الح : و ) cooke, 1986(ومنهم آوك ): stiff clay (قاسي بعض الباحثين قاموا بدراسة األبنية على الطين ال -١ .)katzenback, 1997(و آاتزنباك ) franke, 1991 (و فرانك) yamashita.et.al., 1993(يامشته .)jendeby, 1986(ي وهو جندبا) : soft clay( احد الباحثين قام بدراسة االبنية على الطين الرخو -٢ دوالنيت -٣ ث مان ا الباح ة ) manadolinietal, 1997( أم رب اإلنهياري ى الت ة عل ة المقام درس األبني )pyroclastic soils(. ) line, 1989(فقد درست من قبل الين ) sandy silt(في ترب رملية ) bored pile( أما رآائز الحفر -٤ ).garg, 1979(، وآرآي .)line, 1994(فقد درست من قبل الين ) soft organic soil(ق في الترب العضوية الرخوة رآائز الد-٥ .)kondrachov, 1971(فقد استعرضها آوندراجوف ) silt( بالنسبة لرآائز دق في الغرين -٦ منشأ من الكونكريت ) bridge( جسر أسس قام بمراقبة ) combarieneny, 1982(الباحث آومبرينه أما في فرنسا والذي يقطع الطريق ) ronem(رونم ويقع بالقرب من مدينة ) prestress concrete(لصب مسبق ا ) three spans ( الجسر تالف من ثالث فضاءات ).national road, rn138 ( ١٣٨الوطني رقم الشكل وآما موضح في ) 24.5m، 28m،24.5m (ما أطوال الفضاءات فكانت أ، 13.5mعرض آل فضاء .)١(أدناه )٣(رقم ن ا م ن مالحظته تنتاجات يمك م االس شكل أه ح )٣( ال ذي يوض ة أن ال ال الدائمي ى ) dead loads( األحم عل أحمال التصميم الخدمية أما ،)mn 10.1( آانت a2 ،a3المرقمة ) centrals piles( الدعامات الوسطية )live loads ( آانت)13.92 mn.( لتربة ا لمقطع أما بالنسبة )soil profile ( المحصورة من عمق)2m وهذه المقاومة ) pi=0.5mpa(وتمتلك مقاومة مقدارها ) silt(آانت تتألف من عدة طبقات غرينية ) 10m إلى أسفل طبقة الغرين تقع طبقة من ، )pressure meter pmt test(تم إيجادها باستعمال فحص حقلي هو أسفل منها فتوجد تربة طباشيرية أما ) 2m-5m(مق يتراوح بين وعند ع) red clay layer(الطين األحمر )chalk soil layer ( ن ق م من عم ع ض ين ) 5m-10m(تق راوح ب رتين يت ين األخي ة الطبقت ا مقاوم أم )0.6mpa (ى ا ،)2.0mpa (إل ا أم ون مقاومته دًا تك ة ج ي قوي يرية فه ة الطباش فل الترب ع أس ي تق ة الت الطبق )pi>3.0mpa(. ٣٦ ـال ) weak soil(كون التربة القريبة من السطح تكون ضعيفة ونتيجة ل وتمتلك مقاومة قليلة لذلك تم استعمـ ،)٣(الشكل في ) a3(و ) a2(دعامات الوسطية ال عن طريق الطبقات القوية إلى الرآائز لنقل أحمال الجسر بعد ذلك تم صب ) 800mm(وبقطر ) ٢×٤) (bored piles( استعمال ثمانية رآائز حفر الشكل السابق وضح يربط الرآائز مع بعضها البعض، وان هذا األساس الكونكريتي آان ) concrete footing(أساس آونكريت اد ر و،)8.8m,4.0m×1.1m(بأبع م تقري صميم ت ذا الت ي ه ـامة أن ف ـال ) a2( الدعـ صميمـــها بإهمـ يتم ت س على الرغم إن األساس يمس سطح التربة ) pile group ( ليكون نوع األساس مقاومـــة األساس الكونكريتي مقدار الهبوط أن بعد ذلك تم مراقبة الهبوط حقليًا لهذه الدعامة ووجد ، )l=14m(لذلك أصـبحت الرآائز طويلة )4mm (بالنسبة للدعامــــة أما )a3 ( يصبح ل تم تصميمها باألخــــذ بنظر االعتبار األساس الكونكريتي الضحل ومن المراقبة الحقلية ) l=8m(لذلك أصبحت الرآائز بطول اقل من الرآائز السابقة ) pile raft (األساسنوع اآبر بشكل تقريبي ضعــف قيمة الهبوط لحالة أي) 7mm (إلى يكون مساويا لهذه الحالة للهبوط وجد بان الهبوط )pile group ( اإلجهاد خطأن آونإلىويرجح ذلك (bulb of stress)طع مع الرآائز القصيرة بل لم يتقا ، إضافة إلى آون أن األساس الحصيري الضحل سبب هبوط عالي نتيجة آون التربة الواقعة أسفل وقع أسفل منها . منه ضعيفة :خواص التربة الطينية -٤ ا ن خواص التربة الطينية تتغير مع المحتوى المائي وهناك طرق حقلية بسيطة للتعرف عليها، فمثًال بعض األطي والبعض اآلخر عند اخذ جزء منه بقبضة اليد فانه ) very soft clay(تجري آالسائل مثل الطين الرخو جدًا قليل والبعض اآلخر يتشكل بسهولة عند تسليط ضغط ) soft clay(يترشح بين األصابع وهو الطين الرخو شكل بصعوبة وبالضغط عليه بقوة والبعض اآلخر يت ) firm clay(عليه باألصابع مثل الطين المتوسط القوة ين ال ل الط ين ) hard clay (صلبمث و الط دآ وه شكيلــه اب ن ت ذي ال يمك ر ال ـوع األخي ا النــ يوأم القاس )stiff clay()١٠(. المعلومـات والنتائج الســابقة الموجودة في ومما سبق يمكن تقسيم التربة الطينية إلى خمسة أقسام واعتمادًا على لألطيان المذآورة سلفًا بالقيمة متساويةأو وجد بان هنالك بعض الخواص مشترآة ادر المستخدمة بالبحث المصـ ν=5.0( المشبعة لألطيان سون اوببه وقيمة نس ) (مثل زاوية االحتكاك الداخلي للتربة 0=uφ ( وقيمة الوزن ونسبة (su) للتربة غير المبزولة خواص تكون متغيرة مثل مقاومة القص وتوجد بعض ال ) gs=2.7(النوعي أما الكثافة الكلية فتم إيجادها من قوانين الخواص الفيزيائية للتربة )e ( للمرونة ومعامل يونك ) eo(الفراغات )γ (بالجدول آما و)١(. ):case study(دراسية الحالة ال -٥ ن اجل تو أثيرم يح ت ائز،قبعة ض م اقتراح الرآ ة دراسية ت شكل بةموضح) case study( حال و )a٤(ال المسافة أنعلى اعتبار ) 5.4m×5.4m(وتملك قبعة بأبعاد ) 0.6m×0.6m(بفرض أن الرآائز مربعة وبأبعاد القبعة أما أن ، تلك )t= 0.6 m( ، قبعة الرآائز فرضت بان لها سمك مساوي إلى )٦()s=2d(بين الرآائز هي قبعة غير مستندة على أو أن ال) (4b)الشكل ((pile raft) و يكون نوع األساس تمس سطح تربة طينية مشبعة . )c٤(الشكل آما ب(pile group) و هذا النوع هو التربة ـدًا ـوة جــ ـا تكون التربة الطينية رخــ ، سبعة )very soft clay, su=20 kpa(ثالثة عشـــر موديل انجزت عندمــ ـتة أخرى لحالة )٢(الجدول إضافة إلى حالة عدم وجــود رآائز و آما ب ) pile raft(لحالة pile ( ، وسـ group ( ســبة ى ن دت عل وديالت اعتم ك الم ع تل دت ) l/b(و جمي وديالت أعي ك الم ة ، تل و لحال ين الرخ الط )soft clay, su=30kpa( لحالة الطين متوسط القوة و ) firm clay, su=57.5 kpa( الطين و لحالة stiff ( أو القاسيالطين الصلد و لحالة) hard clay, su=112.5 kpa ( الصلب clay, su=150 kpa.( :البرنامج المستعمل -٦ تخدام زت باس ة انج اة عددي ة، محاآ ذه الدراس ي ه امج ف ربرن سزالعناص دد بالآ المح (plaxis finite element program) د و بشكل ثالثي األبعا مرونة واضحة لتحليل الموديالت و الذي يوفر ٣٧ من ناحية التشوه و االستقرارية للمنشاءات التحليل للتربة و الصخور إمكانية البرنامج له . بصورة غير خطية و (cam-clay type) و (hardening model)امج منها عدة نظريات فشل يتعامل معها البرن . الهندسية ، و لكن نظرية (the soft soil model) و(mohr–coulomb model) شيوعًا هي األآثر لكن النظرية .)٥((mohr – coulomb criterion) آولومب -الفشل المستخدمة بالبحث الحالي هي نظرية مور ستخدم امج الم سابالبرن ى ح ة عل ه القابلي شل ل كل الف د ش ادات و تحدي االت و االجه ة االنفع للترب (strains, stresses and failure states of soil) و يمكن ان يولد العناصر المحددة و آذلك البرنامج .(automatic mesh generation) بصورة اتوماتيكية حول التربة وحدات الطول و القوة و الزمن و آذلك اختيار أبعاد دأ باختيار المعلومات إلى البرنامج يب إدخال عرض بمقدار أربعة مرات من المسالة أبعاد و لجميع الموديالت آانت (soil domain) مجموعة الرآائز (grid) ، إضافة إلى ذلك تم اختيار مقدار المسافة بين (m 20) بمعنى أخر بمقدار ،(z) و (x)باتجاه القبعة و أما عمق التربة أسفل . (5)الشكل و آما ب )رآائز و قبعة الرآائز (و الذي من خالله نستطيع رسم المسالة بدقة آثافة التربة، معامل المرونة، نسبة ( أيضا و تم إدخاله و إدخال خصائص التربة (m 20)قبعة الرآائز فكان و آما موضح (bore hole) يار اإليعاز حفرة اختبارية من خالل اخت) بواسون، مقاومة القص غير المبزولة شكلب ه . )5b(ال تم إدخال ل ي ة الحم وع و قيم ضا ن شبك أي ل الم از لعم ى إيع ضغط عل ك ن د ذل اً و بع اتوماتيك (mesh generation) و من ثم نبدأ بتنفيذ البرنامج بالضغط على اإليعاز (calculation) من اجل تحليل . المسالة :(verification of program) من البرنامج التحقق -٧ انجزت من خالل فحص موديل عملي متكون من ) بالآسز (عملية التحقق من البرنامج المستعمل في البحث 100) مع أساس ضحل حديدي بإبعاد (mm x 10 mm 10) رآيزة حديدية واحدة ذات مقطع مربع mm x 100 mm x 10 mm) تربة من اجل تمثيل حالة أساس و ضع على سطح ال(pile raft) . التربة very)الطينية المشبعة وضعت بداخل الحاوية وبكثافة و بمقاومة قص مناظرة إلى التربة الطينية الرخوة جدا soft clay) . الحاوية آانت بأبعاد(350 mm x 200 mm x 300 mm) عملية وضع التربة تمت بمزج ، هل بمعنى اخر القوامتغيير في ال من حيث مع آمية محتوى مائي قليلة ثم قمنا باختبار التربة التربة الطينية الجافة أن التربة أصبحت تتشكل باليد بصعوبة أو بسهولة و سنستمر بعملية إضافة الماء إلى أن تصبح التربة تترشح لك نقوم بعملية حدلها بداخل ، بعد ذ)١١()التربة تصبح تجري آالسائل(بين أصابع اليد عند اخذ قبضة منها و من ثم نقوم بإجراء عملية لصق الرآيزة باألساس الضحل و (γ=16.76 kn/m3)الحاوية و بكثافة مقدارها و باستعمال (mm 150) عمق بداخل التربة إلى نظام الرآيزة و األساس يتم إدخاله . باستعمال ماآنة اللحيم .(6a)الشكل ـب آما و(mm/sec 1)جك يدوي و بمعدل و عشرين دة أربع بعد االنتهاء من إعداد نموذح التربة مع الرآائز نقوم بتغطيته بكيس من البالستك ثم نترآه لم من اجل قياس التشوه (dial gauge)، بعد ذلك نقوم بتثبيت مقياس للتشوه )١٥(ساعة من اجل أن تتخمر التربة عملية التحميل انجزت باستعمال أوزان . (6b) الشكل فيالعمودي الذي يحصل أسفل األساس و آما مشاهد ا .(6c) و بصورة تدريجية و آما موضح بالشكل (static load)ساآنة الموديل العملي الذي تم انجازه قمن ، قورن ) اإلزاحة –منحني الحمل ( المنحني الناتج من الفحص العملي . ته و لكن باستعمال برنامج بالآسز بإعاد الناتج من برنامج بالآسز و قد وجد بان هناك توافق بين المنحنيين خصوصًا في بداية التحميل و آما مع المنحني .( 6d)بالشكل :حساب قابلية تحمل التربة -٨ إيجاد قيمة أقصى حمل يمكن وجب علينا أوالً ) اإلزاحة –منحني الحمل ( سس الرآائز من اجل إيجاد تصرف ا يتم ذلك من خالل حساب قابلية تحمل التربة لكل حالة مستخدمة بالبحث و بالتالي ا على تلك األسس و أن نسلطه .تخمين الحمل األقصى هذه الطريقة هي طريقة توجد طريقة تصميم مقترحة في هذا البحث لحالة أساس حصيري مع وجود رآائز، س ات ال ى الفحوص دت عل سيطة اعتم ة ــب ة حقلي وديالت مختبري ل أ) pile raft(ابقة لم ن قب زت م نج )combarien,1979,1988 ( وهذه الطريقة تكون مطبقة فقط عندما يكون الحمل عمودي وواقع في مرآز ذلك ــ س النوع وآ ــوعندما تكون الرآائز بنف) rigid footing ( يــا يكون األساس جاســاألساس وآذلك عندم ٣٨ حث اوقد أوصى هذا الب . لحمل المسلط عليها تعتمد على موقعها بل تحمل نفس ا عندما الرآائز في المجموعة ال .)٦( تطبق على حالة موجودة بالواقعأنبان هذه الطريقة يمكن لرآائز فان قابلية تحمل مجموعة ا ) n(مع وجود عدد من الرآائز ) raft footing( أساس حصيري عند وجود )١(ة و آما في المعادل)qu ,pr(الحاصل ستكون مساوية ) pile raft(مع األساس )٦(. qu,pr = qu, r + n.µ.qu, ps + nqu, pb (1) qu,r : األقصى المحسوبة باالعتماد مساحة أساس حـصيري مـساوي إلـى الضحل قابلية تحمل األساس . (d× d) مطروح منها مساحات مقاطع الركائز(b×b)مساحة األساس الكلية qu,ps : قابلية التحمل لغالف الركيزة)pile shaft ( أو مـا يـسمى) قابليـة تحمـل احتكـاك الركيـزة ( )pile ultimate shaft friction (مأخوذة معه تأثيرات المجموعة بالنسبة للركائز. qu,pb : قابلية التحمل لقاعدة الرآيزة)pile ultimate point resistance.( µ : ة زة بالترب اك الرآي ة احتك ى قابلي صيري عل اس الح أثير األس ة بت ه عالق ت ل ن ثاب ارة ع عب )pile skin friction ( عمليًا بفـرض عدم وجــود احتكاك للرآيزة إيجادهيتم و )no shaft friction ( زة)b 1/2 = عمق(إلى نصف عرض األساس األسفل في منطقة مساوية إلىمتجه وإذا آان طول الرآي )pile length ,l ( األساس يتجاوز عرض) b) (l>b ( قابلية تحمل قاعدة الرآيزة أنسنفرض )qu,pb ( .ستكون جدًا قليلة وال تؤثر على قيمة قابلية التحمل الكلية بحساب فسنقوم ،)pile group ( التربة س من نوع مجموعة رآائز ذات قبعة ال تمس سطح أما لحالة أسا أن من النتائج المستخرجة لقابلية تحمل التربة و جد . )٩(قابلية تحمل رآيزة واحدة ونضربها في عدد الرآائز 70) إلى ن قيمته مساوية و آا (l/b=3.0)و لطول رآيزة مقداره (pile raft)أقصى قيمة لها آان عند حالة 000 kn) سيتم تحميل مجموعة الرآائز لكال النوعين ، لذا(pile raft) و (pile group) بصورة تدريجية – load) )النزول -إيجاد منحني الحمل (أقصى قيمة للحمل المسلط على مجموعة الرآائز نصل إلى أن displacement curve). : مناقشة النتائج-٩ su=20,30,57.5,112.5 and ( مختلفة تتراوح من ) su(تم اخذ خمسة أنواع للتربة الطينية المشبعة لها قيم 150 kpa (متغيرة تبدأ من قيمة قبعةوعند نسب طول رآيزة إلى عرض )l/b=0 ( في حالة األساس من نوع )pile raft( ،في حالة األساس من نوع أما )pile group ( قيمة تبدأ من فإنها)l/b=0.25 ( وآال النوعين ).l/b=3.0(ينتهيان بقيمة شكل سلط (7a) ال ل الم ة الحم ين قيم ة ب ح العالق وط ) footing load( يوض ة الهب ع آمي زولم أو الن )settlement ( فل ل أس ز الحاص وع مرآ ن ن اس م ة ) pile group(أس ر مبزول ص غي ة ق د مقاوم عن )su=20kpa ( لى إ رآيزة مساوي أطوالوعند (l/b= 0.25, 0.5, 0.75, 1.0, 2.0 and 3.0 ). أما عالقة لحالة األساس من (su=20)الحمل المسلط بالنزول لحالة الطين الرخو جدًا عند قيمة مقاومة القص غير مبزولة نقصان يحدث ) l/b( قيمة مع زيادة انيوضح و آال الشكلين ،7b) (بالشكل فقد وضحت ) pile raft(نوع ، إضافة إلى ذلك األشكال السابقة مجموعة الرآائز زيادة في قابلية تحمل مع لمجموعة تلك الرآائز الهبوطب وء ة األس ح أن الحال ة (توض ل قليل ة التحم دًا وقابلي الي ج زول ع د ) الن شاهدتها عن ن م ة) l/b=0(يمك لحال )pile raft ( بينما حالة)pile group ( فان الحالة)l/b=0.25 ( سلوك المنحنيات .رهي األخط ) الحمل– األساس و لنوعي )su=30,57.5,112.5 and 150 kpa( المتبقية من التربة الطينية األنواع لحالة ) اإلزاحة )pile group( و )pile raft(إلى الحالة السابقة يكون مشابه تمامًا )الطين الرخو جدًا(. يمكن مشاهدتها ) l/b(عند جميع أطوال الرآيزة ) pile raft(و ) pile group( األساس المقارنة بين نوعي كال ل السابق يوضح انه الشكل .(su=20 kpa)(very soft clay) لحالة الطين الرخو جدًا )8(ل الشك في يكون عند قيمة حمل ثابت، و ويزداد النزول ) applied load(األساسين نالحظ مع زيادة الحمل المسلط يبدأ هناك تقارب بين ) l/b(مع زيادة قيمة و ) pile group( منه في حالة أآثر) pile raft(النزول في حالة ٣٩ يحصل انطباق بين المنحنين عند أن إلى) pile raft(مع منحني ) pile group( اإلزاحة لحالة -منحني الحمل السبب .زةيبدأ بالتحسن مع زيادة طول الرآي ) pile raft( أي أن األساس من نوع )l/b=3.0(طول رآيزة و ذلك يؤدي إلى جالس على تربة ضعيفة)pile raft( في نوع الحصيرياألساس أن في ذلك إلى يرجع أن يمكن أعالهالحالة ، و)pile group (أساس من نوعحدوث نزول عالي اآبر من النزول الحاصل في أن ذات مقاومة عالية، أي على تربة ) pile raft( من نوع أساس تحصل في المنشاءات المائية فعند تصميم بعد لكن الرآائز تقل و أقطار و أطوال أن الحصيري سيتحمل جزء من الحمل المسلط مما يؤدي إلى األساس األساس ضعيفة و بالتالي فان قابلية تحمل القوية تصبح التربة السطحية أن تشغيل المنشأ المائي سيؤدي ذلك إلى صرفه صبح ت تهمل و ي صيري س اسالح وع آأس ن ن ائز ذات ) pile group( م ن برآ والو لك ار و أط أقط ائج المستخرجة في . صغيرة من المفضل من ناحية االستقرارية استعمال وجد،)٩(الشكل اعتمادًا على النت دما تكون التربة الطينية ذات ) pile group(مجموعة رآائز بدون أساس حصيري أي أساس من نوع عن من أما ،األمان هذا من ناحية قليلة (l/b) النسبة ندما تكون تلك الرآائز قصيرة مقاومة قليلة و خصوصًا ع أساس إنشاءاقل من ) pile group ( من نوعأساس إلنشاء الكلفة االقتصادية أن ناحية االقتصادية نالحظ ).pile raft( حصيري مع رآائز األطوال ولجميع ) pile raft(و) pile group( األساس ارنة بين نوعي يتم مالحظة المقـــ )9(الشكل ي فـــ )l/b( عندما تكون التربة الطينية بحالة رخو (su=30 kpa))soft clay (. زيادة في أي أن بصورة عامة ادة في النزول ة ل و .الحمل المســـلط ترافقه زي pile( نزول نالحظ أن(10a) في الشكل)l/b=0.25(حال raft ( هو اآبر من نزول)pile group(عندما يكون الحمل المسلط ثابت . pile(حالة مع المنحني الخاص ب ) pile group(حالة منحني الخاص ب حدوث تقارب بين ال آما يتم مالحظة raft( ى ساوي إل زة م ول الرآي ون ط دما يك ى (l/b=0.5) عن اق أن إل دث انطب ين يح ين المنحني ي ب ة ف حال )l/b=0.75( لمنحنيين حدث مبكراً باق بين ا االنط أن، و هنا نشاهد (l/b=0.75) عندما تكون الرآائز قصيرة حدث قد فان االنطباق (su=20 kpa)لحالة الطين الرخو جدًا بينما (su=30 kpa) لحالة الطين الرخو د أخرًا عن ونمت وال ما تك رةرآال أط ا . (l/b=3.0) ائز آبي ة أم ي حال اس ) l/b=1.0(ف زول األس ون ن يك )pile group ( هو اقل من نزول)pile raft ( ولكن عند زيادة الحمل ما يكون الحمل المسلط صغير عند اس زول ألس ون الن سلط يك زول ) pile raft(الم ن الن ل م زة ) pile group ( اق ول الرآي ادة ط ى وبزي إل )l/b=2.0 ( و)l/b=3.0 ( يكون األساس نوع )pile group ( أفضل من األساس نوع)pile raft ( د عن ادة الحمل المسلط أن يمكن )١٠(الشكل من .)قابلية التحمل اآبر و مقدار النزول أسفل األساس واطىء (زي و ) l/b=2.0(لحالة رآائز طويلة جدًا أو) l/b=0.5(و ) l/b=0.25(نستنتج انه لحالة رآائز قصيرة جدًا )l/b=3.0( فان األساس من ،)pile raft ( يكون اخطر من األساس)pile group ( من ناحية االستقرارية .عند تكون قيمة الحمل المسلط ثابتة ) pile raft ( المقارنة بين نوعي أساس،(su=57.5 kpa)عند تربة طينية متوسطة القوة ذات مقاومة قص عندما تكون أطوال الرآائز صغيرة ).l/b( ولجميع األطوال )١٠(الشكل ب آانت موضحة)pile group ( و )l/b=0.25 ( و(l/b=0.5) الحصيري مع الرآائز قيمة النزول لألساس فان ) pile raft ( اقل من يكون p=50)في بداية التحميل ولكن مع زيادة الحمل إلى ) pile group ( نوع من أساس أسفل الحاصل نزولال 000 kn) اً يتساوى األساسين كال لنزول فان ال ولكن بزيادة ، (b 10)و (a 10)بالشكل و آما موضح تقريب خط أن و السبب في ذلك و يكون تصرف الرآائز معاآس من جديد بين المنحنيين تسليط الحمل يظهر اختالف و (pile tip) قعر الرآيزة أسفل و عندما تكون الرآائز قصيرة سيمر (pile raft) لحالة األساس اإلجهاد من نوع أساس من النزول لحالة اعلي لهذه الحالة عالية و بالتالي يكون النزول األحمالخصوصًا عندما تكون (pile group). من ناحية (pile group) أفضل من (pile raft) أساس يكون )l/b≤0.75 ( إلى زيادة طول الرآيزة مع ائص التربة و ذلك قد حدث بسب التحسن الحاصل في خص) من ناحية الهبوط و قابلية التحمل(االستقرارية في و هذا التحسن (10f) إلى (c 10)باألشكال من و آما )الكثافة، معامل المرونة، مقاومة القص (الطينية الحظنا أن إننا، أي (su=30 kpa) لم يطرأ على حالة التربة الطينية الرخوة السابقة الذآر ) pile raft(أساس عرض أضعاف اصبح طول الرآيزة اآبر بثالثة أن بعدلم تتحسن حتى) pile raft(الحالة الخاصة باألساس .قبعة الرآائز ٤٠ تصبح مساوية القص إلى أن من ناحية الكثافة و معامل المرونة و مقاومة عند تحسين خصائص التربة الطينية ا ، ) الطين الصلب ( (su= 112.5 kpa) إلى pile) األساس المقارنة بين نوعي أننالحظ فإنن group) و (pile raft) حالة التربة الطينية القاسية تكون مشابه إلى (su=150 kpa) ١١(آما باألشكال و ( أن األساس ) l/b( طول رآيزة ألي وبعد المقارنة بين نوعي األساسين آما في األشكال السابقة وجد .)١٢(و الثاني األساس ول هو اقل من نزول أي أن نزول األساس األ(pile group) أفضل من pile raft)(من نوع أآثر يكون (pile raft) األساس الحصيري مع الرآائز أن أخر، بمعنى عندما تكون قيمة الحمل المسلط ثابتة عندما تكون مقاومة القص غير المبزولة للتربة (pile group) مجموعة الرآائزأساس و استقرارية من أمان kpa) (s 112.5 اآبر من ≥ ≥ u أسفل األساس الحصيري أصبحت التربة مقاومة أن يعود إلى و السبب في ذلك دًا (pile raft)عالية و بالتالي فان مقاومة األساس تكون مساوية إلى مجموع مقاومة األساس الحصيري زائ .مقاومة مجموعة الرآائز هو اقل (pile raft) النزول في أن يوضح نية صلبة و لتربة طي(l/b=0.25)لحالة باالخاص (11a)الشكل سيكون السلوك (p=60 000 kn) أآثر من إلى ولكن مع زيادة الحمل المسلط (pile group)من النزول عند pile)اقل من نزول و يصبح (pile raft)يرجع نزول l/b) (0.5 بزيادة طول الرآيزة معاآس و لكن group)األساس أي يكون (pile raft)قاسي عند طين . هو األفضل ألي قيمة حمل(su= 150 kpa) و عند يكون الفرق في النزول بين األساسين (l/b=1.0)نسبة طول رآيزة إلى عرض قبعة الرآائز مساوي إلى (pile group) و (pile raft) ر شاهد آبي ا م شكل و آم سابق، و (12d)بال شكل ال ن ال د م ل عن ة حم قيم عندما (75mm) قيم النزول المناظرة لذلك الحمل تكون مساوية إلى أن نالحظ (p=70 000 kn)مقدارها مع و(230mm) له قيمة ال آانت (pile group) ألساس من نوع بينما(pile raft)يكون األساس من نوع .سيقل) اإلزاحة–الحمل ( فان الفرق بين المنحنيين (l/b)زيادة النسبة :االستنتاجات -٩ الحاصل في (vertical displacement) العمودي تقليل النزول إلى يؤدي ) l/b( زيادة طول الرآيزة -١ وذلك لكون أن منحني ) pile raft system( و النوع ) pile group system ( ن نوع نظام الرآائز م أنواع هذا السلوك يكون ثابت لجميع و (2)الشكل سيتقاطع مع الرآائز و آما في ) bulb of stress(اإلجهاد . الطين الرخو جدًا إلى حالة الطين الصلد جدًا حالةالترب الطينية المشبعة من ا، )very soft clay( عندمـا التربة الطينية تكون بحالة رخوة جدًا -٢ نالحظ انطباق منحني الحملفإنن عند أما ، )pile group(عندما يكون األســاس من نوع ) l/b=0.75(مع حالة ) l/b=0.5( لحــالة اإلزاحة ا نالحظ تقارب آبير جدًا بين الحالتين ) pile raft( من نوع أساس و آما ) l/b=1.0(و ) l/b=0.75(فإنن .(7)بالشكل امج بالآسز مع المنحني – بين منحني الحمل (% 90) وجود تقارب بنسبة -٣ االزاحة المستخرج من برن .العملي ) l/b=0.25(وعند أطوال رآائز من ) very soft clay(عندما تكون التربة الطينية المشبعة رخوة جدًا -٤ يقع أسفل من المنحني ) pile raft( اإلزاحة ألساس من نوع -نالحظ أن منحني الحمل ) l/b=2.0(إلى pile( نزول من األساس تكون اخطر من ناحية ال) pile raft(بمعنى أخر أن حالة ) pile group(ألساس group ( و نالحظ تساوي مقدار النزول عندما يكون طول الرآيزة)l/b=3.0.( ) pile group( من نوع أساس نزول منهو اآبر) pile raft(ســاس من نوع ألنزول العند حمل ثابت، -٥ ًا ل ) l/b=0.5(و) l/b=0.25(عندما تكون الرآائز قصيرة عندما يكون كال النوعين ويتساوى النزول تقريب pile( يكون نزول ، بينما عندما يتساوى طول الرآائز مع عرض القبعة)l/b=0.75(طول الرآائز group ( اآبر من)pile raft(بزيادة يكون السلوك معاآس و آذلك المسلطةاألحمال بزيادة في البداية و لكن ما تكون التربة عند ) pile raft( من أفضل هو ) pile group (أساسيكون ) l/b=3.0 (إلى الرآائز أطوال .)su=30kpa (ةرخوطينية وة -٦ ة رخ ة طيني ة ترب ل (su=30 kpa) لحال ي الحم ين منحن اق ب وع – ، انطب ن ن اس م زول ألس الن )pile group ( اس ي ألس ع المنحن زة ) pile raft ( م ول رآي د ط يحدث عن ذ)l/b=0.75(س ا ، و أن ه ٤١ فان (su=20 kpa) لحالة الطين الرخو جدًا ا االنطباق بين المنحنيين حدث عند أطوال رآائز قليلة بينم .(l/b=3.0) ما يكون طول الرآيزة ثالثة أضعاف عرض قبعة الرآائزاالنطباق سيحدث عند ساس من نوع أل) اإلزاحة -الحمل (نشاهد أن منحني ) su=57.5 kpa(في حالة الطين المتوسط المقاومة -٧ )pile group ( ل ي الحم فل منحن ع أس ة -يق وع اإلزاح ن ن اس م زة)pile raft(ألس وال رآي د أط عن )l/b=0.25 ( و)l/b=0.5 ( ل ي الحم دأ منحن ن يب ة-ولك اساإلزاح وق ) pile group ( لألس صعود ف بال .بزيادة األحمال المسلطة) pile raft(اإلزاحة الخاص بنوع األساس -منحني الحمل د-٨ زة عن ول رآي وع )l/b≤0.75 ( ط ن ن اس م ان األس اس (pile raft)، ف ن األس ضل م ون أف يك (pile group)عندما تكون التربة متوسطة القوة و ذلك من ناحية االستقرارية(firm clay) ، و هذا التحسن أصبح حتى بعد أن (soft clay) ة التربة الطينية الرخوة حاللم يطرأ على ) pile raft(ساس األ مقاومة في .طول الرآيزة اآبر بثالثة أضعاف عرض قبعة الرآائز لجميع أطوال و ) مقاومة عالية ( (kpa 112.5) عندما تكون مقاومة القص غير المبزولة اآبر أو تساوي -٩ pile ( نوع منساساصل أسفل األ النزول الحيكون) l/b=3.0(إلى حالة ) l/b=0.25(الرآائز من حالة raft (نوع من ساس اقل من نزول أل)pile group( إال، لذلك ال يتم استعمال األساس الحصيري مع الرآائز .في حالة آون خصائص التربة الطينية المشبعة جيدة :التوصيات للعمل المستقبلي ١٠ في حالة آون تلك األسس خاصة بالمنشأت ) pile raft( عدم تصميم األساس آأساس حصيري مع رآائز -١ عندما أو الترب االنتفاخية أو الترب الجبسية تكون ذات المشاآل مثل المنشأ أسفل الترب الواقعة أنالمائية أو . ضعيفةتلك التربتكون خصائص أثلنفس الحاالت المأخوذة بالبحث) experimental study( عمل دراسة عملية -٢ منسوب ير مع إدخال ت ).pile raft(و ) pile group(على سلوك األساس من نوع ) water table level (المياه الجوفية ة -٣ ة الرملي يكن الترب ة ول ن الترب ر م وع أخ تعمال ن ة ) sandy soil( اس سب آثاف د ن وعن )relative density, dr (مختلفة. :المصادر ١١ 1borel, s. and olivier, f. (1998), " some observation on piled footing", 2 nd int. phd symposium in civil engineering, budapest, france. 2bowles, j. (1996), "foundation analysis and design" , u.s.a 3comodromos, e.m. and bareka, s.v. (2000), " response prediction for axially loaded pile groups in clays using 3d nonlinear analysis", department of civil engineering, university of thessaly, greece, oska conference. 4cui, k., de´fossez, p. and richard, g. (2007), " a new approach for modelling vertical stress distribution at the soil/tyre interface to predict the compaction of cultivated soils by using the plaxis code", science direct journal, still-2374, pp 1-11. 5das, b.m (2004), "principles of foundation engineering", california state university, sacrament , u.s.a 6national high way institute (1998),"design and construction of driven pile foundations" ,workshop , manual-volume i and ii , u.s. department of transportation. 7poulos , h.g. and davis, e.h. (1986), "pile foundation analysis and design" , university of sunday, usa. 8poulos, h.g. and davis, e.h. (1974), "elastic solutions for soil and rock mechanics", university of sydney, printed in the united state of america. 9salgado, r., lyamin, a.v. , sloan, s.w. and yu, h. s. (2004), " twoand three-dimensional bearing capacity of foundations in clay", ge´otechnique journal 54, no. 5, pp 297–306. ٤٢ 10simons , n.e. and menzies, b.k. (1976), "a short course in foundation engineering", richmond , surrey , wimbledon. 11tejchman, a. , gwizdala, k. , krasinski, a. and slabek, a. (2000) , " model tests of piled raft foundation", geotechnical department, gdansk university of technology, gdansk, poland, oska conference. 12tomlineson, m.j. (1977) "pile design and construction practice" , garden city , london. 13trochanis, a. m., bielak, j. and christiano, p.(1991b),"three dimensional nonlinear study of piles", journal of geotechnical engineering divison , asce, vol.117, no.3, pp 429-447. 14wakai, a. , gose, s. and ugai, k. (1999), " 3-d elasto-plastic finite element analyses of pile foundations subjected to lateral loading", journal of soils and foundations (soils found.), vol. 39, no.1, pp. 97-111. 15wiesner, t.j. and brown, p.t.(1980), " laboratory tests on model piled raft foundations", journal of geotechnical engineering division, asce, vol.106, no.gt7, pp.767-783. )١٠(و ) ٢ (خواص الترب الطينية المستعملة): ١(الجدول (eo)نسبة الفجوات نوع التربة ت المقاومة غير المبزولة (su), kpa معامل يونك للمرونة (e), kpa الكثافة الكلية (γ), kn/m3 very soft clay( 1.4 20 8500 16.76(الطين الرخو جدًا -١ soft clay( 0.9 30 15000 18.58(خو الطين الر -٢ firm clay( 0.75 57.5 32500 19.34 (الطين متوسط القوة -٣ hard clay( 0.6 112.5 75000 20.233 (صلبالطين ال -٤ stiff clay( 0.5 150 137500 20.93 ( أو القاسيالطين الصلد -٥ .(pile group)و ) pile raft (يوضح الحاالت لألساس): ٢(الجدول pile group, l/b pile raft, l/b الموديل -----0 ١ 0.25 0.25 ٢ 0.5 0.5 ٣ 0.75 0.75 ٤ 1.0 1.0 ٥ 2.0 2.0 ٦ 3.0 3.0 ٧ ٤٣ pile cap g.s.l pile cap pile pile cap pile s s l1 s s l2 piles w.t .(a) القبعة عبارة عن أساس حصيري (pile raft) .(b) القبعة ليست أساس حصيري (pile group) .(c)خزان ارضي .(e)ة الرآائز ال تمس سطح األرضقبع أنواع مختلفة من اسس الرآائز ): ١(الشكل .(d)مجموعة رآائز بداخل تربة انتفاخية pile cap pile w.t g.s.l l problematic soil pile cap g.s.l l1 bulb of stress pile cap g.s.l building l2 bulb of stress pile cap g.s.l building (a) .هاد يتقاطع مع الرآائزخط اإلج (b) .خط اإلجهاد يقع أسفل الرآائز )٨(العالقة بين طول الرآائز و موقع خط اإلجهاد): ٢(الشكل ٤٤ ngfالمناسيب العامة للجسر بالنسبة لدولة فرنسا )١(يوضح فضاءات جسر في مدينة فرنسا) ٣(الشكل b=5.4 m b =5 .4 m d=0.6 m t=0.6 m l b 0. 6 m 0. 6 m 1. 2 m 0. 6 m 0. 6 m 0. 6 m pile 1. 2 m .(c)نوع س مناأس ) pile group( t=0.6 m 0.3 m l b .(b)نوع س مناأس )pile raft( .(a)لمجموعة رآائز المسقط األفقي (case study)الدراسية الحالة ): ٤(الشكل ٤٥ soil boundary cap piles load type bore hole mesh generation )a .(إدخال أبعاد التربة المستخدمة بالمسالة )b .(إدخال خصائص التربة و الحمل و عمل المشبك إدخال خصائص التربة و الحمل و عمل المشبك): ٥(الشكل (c) dial gauge shallow footing static loading (b) loading pan (a) raft footing pile footing soil used 0 5 10 15 20 25 30 35 40 45 50 vertical stress (kpa) 0.0 1.0 2.0 3.0 4.0 5.0 v er tic al d is pl ac em en t ( m )* 10 experimental work theory work (plaxis) (d) -3 مقارنة الموديل العملي المنجز بالمختبر مع الموديل النظري باستخدام برنامج بالآسز): ٦(الشكل ٤٦ 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 8000 se tt le m en t ( m m ) pile group & su=20 kpa l/b=3.0 l/b=2.0 l/b=1.0 l/b=0.75 l/b=0.5 l/b=0.25 .(a) أساس من نوع(pile group) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 8000 se tt le m en t ( m m ) pile raft & su=20 kpa l/b=3.0 l/b=2.0 l/b=1.0 l/b=0.75 l/b=0.5 l/b=0.25 l/b=0 .(b) أساس من نوع(pile raft) (su= 20 kpa)ن الرخو جدًا عالقة الحمل المسلط بالنزول لحالة الطي) ٧(الشكل ٤٧ ٤٨ 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 se tt le m en t ( m m ) l/b=0.25 & su=20 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 se tt le m en t ( m m ) l/b=0.5 & su=20 kpa pile group pile raft (a) (b) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 se tt le m en t ( m m ) l/b=1.0 & su=20 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 se tt le m en t ( m m ) l/b=0.75 & su=20 kpa pile group pile raft (d) (c) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 se tt le m en t ( m m 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 7000 se tt le m en t ( m m ) l/b=3.0 & su=20 kpa pile group pile raft (f) l/b=2.0 & su=20 kpa pile group pile raft (e) ) )su=20 kpa(عند قيمة ) pile raft(وأساس من نوع ) pile group(مقارنة بين أساس من نوع ): 8(الشكل ٤٩ 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 se tt le m en t ( m m ) l/b=0.25 & su=30 kpa pile group pile raft (a) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 se tt le m en t ( m m ) l/b=0.5 & su=30 kpa pile group pile raft (b) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 se tt le m en t ( m m ) l/b=1.0 & su=30 kpa pile group pile raft (d) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 se tt le m en t ( m m ) l/b=0.75 & su=30 kpa pile group pile raft (c) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 se tt le m en t ( m m ) l/b=2.0 & su=30 kpa pile group pile raft(e) 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 5000 6000 se tt le m en t ( m m ) l/b=3.0 & su=30 kpa pile group pile raft(f) ).su=30 kpa(عند قيمة ) pile raft(وأساس من نوع ) pile group(مقارنة بين أساس من نوع ): 9(الشكل ٥٠ 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 se tt le m en t ( m m ) l/b=0.25 & su=57.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 se tt le m en t ( m m ) l/b=0.5 & su=57.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 se tt le m en t ( m m ) l/b=0.75 & su=57.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 se tt le m en t ( m m ) l/b=1.0 & su=57.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 1000 2000 3000 4000 se tt le m en t ( m m ) l/b=2.0 & su=57.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 2000 2500 3000 3500 4000 se tt le m en t ( m m ) l/b=3.0 & su=57.5 kpa pile group pile raft(e) (f) (c) (d) (a) (b) )su=57.5 kpa(عند قيمة ) pile raft(وأساس من نوع ) pile group(مقارنة بين أساس من نوع ): 10(ل الشك 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 2000 2500 se tt le m en t ( m m ) l/b=0.25 & su=112.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 2000 2500 se tt le m en t ( m m ) l/b=0.5 & su=112.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 2000 2500 se tt le m en t ( m m ) l/b=0.75 & su=112.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 200 400 600 800 se tt le m en t ( m m ) l/b=1.0 & su=112.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 50 100 150 200 se tt le m en t ( m m ) l/b=2.0 & su=112.5 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 10 20 30 40 50 60 se tt le m en t ( m m ) l/b=3.0 & su=112.5 kpa pile group pile raft (e) (f) (d)(c) (b)(a) )su=112.5kpa(عند قيمة ) pile raft(وأساس من نوع ) pile group(مقارنة بين أساس من نوع ): ١١(الشكل ٥١ 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 se tt le m en t ( m m ) l/b=0.25 & su=150 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 se tt le m en t ( m m ) l/b=0.75 & su=150 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 500 1000 1500 se tt le m en t ( m m ) l/b=0.5 & su=150 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 50 100 150 200 250 se tt le m en t ( m m ) l/b=1.0 & su=150 kpa pile group pile raft (d)(c) (b)(a) 0 20000 40000 60000 80000 footing load (kn) 0 10 20 30 40 50 se tt le m en t ( m m ) l/b=2.0 & su=150 kpa pile group pile raft 0 20000 40000 60000 80000 footing load (kn) 0 10 20 30 40 se tt le m en t ( m m ) l/b=3.0 & su=150 kpa pile group pile raft (f)(e) )su=150 kpa(عند قيمة ) pile raft(وأساس من نوع ) pile group(مقارنة بين أساس من نوع ): ١٢(الشكل ٥٢ 13-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 half bridge resonant inverter abdulhasan abdullah kadhim. assistant lecturer / univ. of mustansiriya/colledge of engineering/ elect. eng. dep. email:abdulhasan_abdulla@yahoo.com abstruct the aim of this work is to develop a resonant inverter using half bridge inverter configuration which feed power to induction heater during positive and negative cycle of load current. such system will substitute the using of full bridge configuration, hence a reduction in both cost and complexity. a full analysis of the proposed circuit using igbts at a frequency of 50 khz, and a power of 1.8 kw is presented. the practical results agree with that of the simulation, and their waveforms are closely similar, so the proposed inverter is completely valid. keywords:bridge transistor, gate drive, induction heating, orcad, resonant inverter. . ).( . . igbts٥٠١,٨ . . introduction to feed power to the load during both positive and negative cycles of load current, a full bridge inverter is used as in [3], and the soft switching of such system is explained in [1], but in the conventional half bridge resonant inverter shown in fig. 1 the power is fed to the load only during the period when t1 is turned on. the suggested design fig. 2 feed power to load during both periods of operation of t1 and t2. the value of the capacitors (c1 & c2) is half the value of (c) used in fig.1, but two capacitors are needed so their sum is the same of that used in conventional approach. these capacitors should be from same type and manufacturer so that their effective series resistance is the same. operation modes mode 1 this mode is shown in fig. 3, where t1 is closed and t2 is open. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 mode 2 this mode is shown in fig. 4, where t1 is open and d2 is closed mode 3 this mode is shown in fig. 5, where t1 is open and t2 is closed. mode 4 this mode is shown in fig. 6, where d1 is closed and t2 is open. resonance frequency in the four modes of operation figures (3-6) the equivalent circuit consists of parallel impedance (c, r&l) in series with capacitive impedance (c): in modes (1&2) the currents (ic1, ic2, and il) are as indicated in the figures (3&4), so the source voltage is applied in the positive direction. in modes (3&4) all the currents (ic1, ic2, and il) are reveres and hence the source voltage is applied in the negative direction. hence the equivalent circuit can be represented by using a square-wave voltage source, parallel impedance, and series impedance as shown in fig. 7. the laplace transform of the source voltage (vs) is as in eq (1) below: [2] (1) now from fig. 7 the parallel impedance zp is: (2) where zc is the capacitor impedance ( , zl is the load impedance (r+sl). the total impedance zt is: (3) the voltage across the parallel branch (vp) is: (4) (5) the load current is (6) (7) by simplifying (8) substituting eq.s (1), (7) and (8) in (5) to get: and by simplifying: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 (9) substituting (9) in (6): (10) after simplifying: (11) hence it can be obtained that il is a periodic function and its function for one half cycle is: (12) where: (13) (14) where (15) in this work v = 50v, r = 0.5 ohm, l = 5μh, c = 1μf, so fo can be calculated from eq. (14), hence fo = 49.7 khz. the maximum current ilmax ot = ( /2) or (t=t/4 = 5μs) and can be calculated from eq. (12), driving circuit if the output impedance of the gate drive circuit is high, the change of collector-emitter voltage at high frequencies will be reflected to the gate circuit, causing permanent damage. [4]. so in this work a low output impedance driving circuit is used, that is not only gate-emitter voltage rating not exceeded, but also the voltage transient at the gate is contained to a level at which spurious turn-on not occurred. this driving circuit is ir2110 (international rectifier control ic). but this driving circuit control ic suffers from: i. low output current. ii. it have a share common for both input and output the problem (i) solved by using a power amplification buffer between the control ic and the gateemitter, [5]. the problem (ii) solved by inserting a resistance between the common and the low side emitter [6]. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 simulation the simulation is implemented using orcad 16.2 software. the circuit used in this simulation is show in fig. 8. fig. 9 shows the waveforms of load current and collector-emitter voltage. the current waveform is sinusoidal of peak value of 52 a which is very near to the calculated theoretical value (49.96 a). also it is obvious that the current is switched at zero voltage (resonance). also it is obvious that the frequency is 50 khz equal with calculated value. fig. 10 shows the waveforms of load current and load voltage. the waveform of the load voltage is not strange, it is expected to be like this because in mode 1& 4 (fig. 3&6) the load voltage is the voltage of capacitor c1, and in modes 2&3 (fig. 4&5) the load voltage is the voltage of capacitor c2, so the switching between these modes is the reason of the step change in the load voltage, however this change is not sever as it shown equal about to 40v,and still the load current waveform is a sine wave. in fig. 11 the voltage waveforms of the capacitors c1 & c2 are shown. the waveforms are pure sinusoidal, so in each time of the four modes (3-6), a pure sine voltage is applied across the load. practical result in fig.12 the gate signal waveforms are shown, the dead time is 1μs, the frequency is 50 khz. voltage scale is 5v/div, time scale is 5μs/div. in fig. 13 the voltage waveforms of load current and transistor collector-emitter voltage are shown. the current is pure sine wave, and the switching is in the zero current crossing. the practical result is completely same as the simulated result (fig. 9), but the waveforms in the simulation is in the same scale, but practically is not. voltage scale is 20 v/div; current scale is 15a/div, time scale 5μs/div in fig. 14 the load voltage and load current are shown. the peak load current is about 47a which is very similar to the simulated and with the calculated one. the voltage scale is 20 v/div, current scale is 15 a/div, time scale is 5μs/div. in fig. 15 the voltage waveforms of both c1 and c2 are shown. the waveforms are pure sine waves and completely similar to the simulated one. voltage scale 20v/div, time scale 5μs/div. fig. 16 shows a part of the project. in fig. 17 and fig. 18 the element heated and reached the red color at about 700°. references [1] "soft switching series resonant converter for induction heating applications" ieee, international conference 1995. [2] katsuhiko ogata: "modern control engineering", fourth edition, 2002, pp 46 [3] xiaorong zhu, yonglong peng, xinchun shi, heming li, "200kw f400khz high frequency inverter for induction heating application", ieee peds 2005. [4] international rectifier application note, an-936, sec 3. [5] international rectifier application note, an-978, sec 7. [6] international rectifier design tip, dt97-3, sec 8. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 t1 t2 d2 v l c r d1 fig. 1 conventional half bridge inverter resonant inverter t1 t2 c1 d1 l d2 v r c2 fig. 2 suggested design al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 t1 t2 c1 l v r c2 ic1 ic2 il fig. 3 (in this mode only t1 is turned-on) d2 t1 c1 l v r c2 ic2 ic1 il fig. 4 (in this mode only d2 is turned-on) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 t2 t1 c1 l v r c2 ic1 il ic2 fig. 5 in this mode only t2 is turned-on d1 t2 c1 l v r c2 ic2 ic1 il fig. 6 (in this mode only d1 is turned-on) (a) (b) fig. 7 (a) equivalent source voltage, (b) complete equivalent circuit. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 z1 mg50n2y s9 z2 mg50n2y s9 c2 1u v2 50vdc 0v 0v bus 50.00v 0 2.055mv v3td = 1n tf = 1n pw = 10u per = 20u v1 = 0 tr = 1n v2 = 15 v4td = 1n tf = 1n pw = 10u per = 20u v1 = 15 tr = 1n v2 = 0 load 2.055mv r4 10 r510 2.055mv 2.055mv 15.00v c3 0.1n c4 0.1n r1 0.5 r2 0.5 vv+ d14 mr876 d15 mr876 n 2.055mv 2.055mv 2.055mv l4 4.9uh r3 0.55 15.00v fig. 8 the circuit used in the simulation ti 400us 410us 420us 430us 440us i(l4) v(bus,load) -80 -40 0 40 80 fig. 9 the load current (il) and collector-emitter (vce) versus time al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ti 400us 410us 420us 430us 440us i(l4) v(l4:1,n) -200 -100 0 100 200 fig.10 load current (il) and load voltage (vl) versus time al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 400us 410us 420us 430us v(bus,n) v(0,n) -200v -100v 0v 100v 200v fig. 11 the capacitor voltages vc1 (upper waveform) and vc2 (lower waveform) versus time. fig. 12 the gating signals al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. 13 the load current (il) and collector-emitter (vce) versus time fig.14 load current (il) and load voltage (vl) versus time. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. 15 the capacitor voltages vc1 and vc2 versus time. fig. 16 a picture to part of the project al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. 17 the element in the coil is heated and reached the red color. fig. 18 the element in the coil is completely heated and brighten at a temperature of 700 c°. introduction al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 investigation the effect of the reactive muffler connections on noise attenuation على تخفيض الضوضاءالتفاعلي م الصوتكاتل طرق الربط تأثيردراسة dr. muna s. kassim college of engineering al-mustansiriya u munahdr@yahoo.com abstract a pollutant of concern to the mankind is the exhaust noise in the internal combustion engine. however this noise can be reduced sufficiently by means of a well designed muffler. the suitable design and development will help to reduce the noise level. the author design and fabricate a reactive muffler, spherical and cylinder shapes, afterward compared the noise level for these shapes with parallel and series connections. transmission loss and transmission coefficient are calculated experimentally and theoretically for one, double and three mufflers in parallel and in series. exhaust noise levels will aid the manufacturer in determining the correct muffler to meet the required noise reduction. these mufflers tested in frequency ranging between (50-600) hz. in this study, the rustles show that the parallel connection is best than the series connection. keywords: muffler connection, noise reduction. الخالصــــــة هذه الضوضاء يمكن ان تقلل بما فيه الكفاية حيث انضوضاء العادم في محرك االحتراق الداخلي ب متزايد االهتما في هذه الدراسة .الضوضاء هذه يساعدان على تقليل مستوىالن التصميم المناسب وتطويره بواسطة كاتم الصوت لهذه االشكال بربط مستوى الضوضاء ةقارنحيث تم ماسطواني الشكل تفاعلي كروي و كاتمع يم وتصنيمتم تص واحد كاتملونظري محسوبان بشكل تجريبي (tcرسال )اال ( ومعاملtlاالرسال ) خسارة. التوازي والتوالي كواتمالهذه ا ،الصحيح لكاتمبالتوالي والتوازي . مستويات ضوضاء العادم ستساعد في تقرير ا كواتموثالثة ثنائيو للكاتم افضل من تز . في هذه الدراسة اثبتت النتائج ان ربط التوازيير( ه055-05اختبرت في تردد يتراوح ما بين ) .ربط التوالي al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 nomenclature area, m 2 a sound speed ,m/s c diameter of expansion chamber d number of waves k incident pressure pi reflected wave pressure pr cross section area s al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 1-introduction in an automobile, the exhaust system carries exhaust gases from the engine's combustion chamber to the atmosphere. exhaust noise of internal combustion engines iron mentis known to be the biggest pollutant of the present-day urban environment. fortunately, however, this noise can be reduced sufficiently by means of a well-designed muffler which is also known as silence. nowadays, the silencers are made with different shapes, volumes and very complex internal sections. as a consequence of the constructive complexity, there is a region inside it where the onedimensional theory cannot be applied. this occurs due to the appearance of multi-dimensional waves with the simultaneous propagation of waves in the axial and radial directions when the excitation reaches the frequency range where the wavelength is smaller than the largest dimension of the cross-section of the silencer. such effect causes a considerable difference between the plane wave theory results and the experimental results (munjal et al., 1987). muna, et. al., 2012, found that the tailpipe acts as a resonant cavity that couples with the muffler cavity. in order to minimize the noise level, different pipe lengths of inlet and outlet (discharge) tubes are studied with a specific diameter. the conclusion was that the taller outlet pipe the higher noise attenuation. orifice plates are most commonly used as primary element for flow measurement in pipe line based on the principle of measurement of differential pressure created when an obstruction is placed in the fluid flow due to increase in fluid velocity. orifice plate cover a wide range of applications of fluid and operating conditions they give an acceptable level of uncertainties at lowest cost and long life without require maintenance. the orifice plates are correctly finished to the dimensions, surface roughness and flatness to the applicable standard these plates are recommended for clean liquid, gasses & steam flow. the orifice plate bore can be made in many configurations to handle various flow measurement jobs. lenzi and barbieri, 2011, studied the application of shape and parametric optimization techniques in the study of reactive silencers with extended inlet and outlet ducts. parametric optimization is employed to evaluate the appropriate size of the inlet and outlet ducts. shape optimization is employed to establish the proper profile of these ducts in order to improve the acoustic features of these mufflers in a specific frequency range. the objective function used in the optimization processes is defined through the average transmission loss (tl) for the desired frequency range. this type of objective function is strongly non-linear and the genetic algorithm, ga, was chosen as a mathematical method for determining the maximum of this function. the finite element method with an axisymmetric formulation along with the modified four-parameter method are used to calculate the tl. the hermit polynomials were used in the shape optimization in order to obtain local boundary approximations with c1 continuity. the results showed the optimization efficiency of the inlet ducts profile for acting in specific frequency ranges with gains up to 20db with respect to silencers without shape optimization. the numerical analyses agree well with experimental results. muthana et. al, 2011, built a test rig for a reactive muffler. different orifice shapes are used with the same bore area to study the effect of the orifice shape on noise reduction. also the effect of the number of orifices in one plate and multi plate orifice is discussed. it has been found that the multi plate circle orifice and triangle orifice give the most suitable results. shape optimization of multi-chamber mufflers with plug-inlet tube on a venting process by genetic algorithms were investigated by (min-chie chiu, 2010). a numerical case for eliminating al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 broadband steam blow-off noise using multi-chamber plug-inlet mufflers in conjunction with a genetic algorithm (ga) as well as a numerical decoupling technique, all within a space-constrained pressure drop. to verify the reliability of the ga optimization, optimal noise abatements for various pure tones on a one-chamber plug-inlet muffler are examined. of course, the accuracy of the mathematical model must be supported by experimental data. subsequently, optimal results then indicate that the maximal sound transmission losses are indeed located at the desired target tones. consequently, both pressure drop and acoustical performance will increase when the diameters (at inlet tubes and perforated holes), the perforated ratio, and the length of perforated tubes are decreased. zhaorong, 2009, studied the internal laws of silencers' acoustic attenuation performance, when the cross-sectional shape, length and diameter of the expansion chamber changed. based on the bem-fem coupled model and to combine with the improved four-pole parameters method, the transmission loss (tl) was calculated. it is pointed that the flatter the expansion chamber is, the worse the performance is. when the length decreases, the domes of the tl become broader, and the number of domes decreases. when the diameter increases, the tl increases, but the growth rate and the inactive frequency decrease. the results indicate that by using computer modeling analysis, it is sensible to optimize the shape to meet the needs of the eliminating frequency band and the applied circumstance. in all muffler designs the tailpipe length can have an important effect. rahman, et. al., 2005, investigated the most effective means of reducing noise by changing the design of muffler. but, muffler requires specific design and construction considering various noise parameters produced by the engine. the conventional design does not include much of a parametric noise analysis or other engine characteristics. a muffler for stationary petrol engine has been designed and manufactured. the performance characteristics, i.e. noise reduction capability of the muffler, has been tested and compared with that of the conventional muffler. the result has been found to be quite satisfactory. in this paper, the reactive silencers with two shapes (spherical and cylindrical) are used with connection parallel and series one, two, and three silences to detect the effect of the shape on noise attenuation in the muffler. 2. theoretical considration the active silencer is capable to reduce the exhaust noise from 91 db to 78 db after the tail pipe outlet, with a back pressure of 3 kpa to the engine. the quantity most often used to measure the “strength” of a sound wave is the sound pressure level (lp or spl) measured with respect to a standard reference pressure of p ref = 2 ×10 5 pa. the sound pressure level can be calculated using the following formula (beranek and ver, 1992): spl=20 log10(p/pref)(db) (1) there are several parameters to describe the acoustic attenuation performance of an expansion chamber. these include the noise reduction (nr), the insertion loss (il) and the transmission loss (tl). among these acoustic parameters, the tl is the only one that can be easily calculated and measured according to the main aim of this paper. it is defined as the difference in the sound al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 717 power level between the incident wave exciting the mufflers wi and the transmitted wave wt to an anechoic termination. tl=10log10 (wi/wt) (2) (3) k= w/c w=2πf where: (w): angular velocity d = diameter of the expansion chamber (15.3 cm) d=diameter of the inlet pipe (4.7cm) (k) = no. of waves (l)= length of expansion chamber (24cm) (c)= sound speed (343m/sec) the transmission coefficient in the silencer can be calculated from the following (harris, 1979) (4) the experimental results contain the calculation to find the values of transmission losses (tl) which equal the difference between sound pressure level at inlet and outlet, and find transmission coefficient (tc). 3. experimental work test parts arrangement shown in figure (1). two mufflers with two shapes spherical and cylindrical were fabricated as test section. the spherical muffler was formed carefully from copper sheet with diameter 21cm as shown in figure (2). but the cylindrical muffler were formed a galvanized steel sheet pipe having a diameter of 21 cm and 25cm length as shown in figure (3). the inside of silencer is empty because this study is concerned with the effect of shape of silencer on noise reduction. the diameter of the inlet pipe is taken same as the diameter of the exhaust of the silencer and equal is (5 cm) for both design. the signal generator is connected to the amplifier which is connected to the loudspeaker. the loudspeaker is isolated in the box to prevent sound reflection and also to prevent any external disturbance. the other end of the box is connected to the cone which is joined to the spl meter. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 the signal generator is turned on to give assign with frequency from (50 to 600) hz step 50hz, a, and select sinusoidal wave. the spl meter readings are recorded, then the test muffler is placed at the con end and the spl meter is placed at the mufflers other end. the test rig is made from the following components: 1-signal generator: to generate sound signal with different frequency and operate (0hz to more than 1000hz). 2amplifier. 3-loudspeaker: 8 inch size 4a box: to cover the loudspeaker, insulated from inside to prevent sound reflection. 5a cone-shape connector: attached to the box to force the sound wave pass in one path. 6pipes: to connect the experiments parts (the signal generator, loud speaker, box and cone) 7reactive muffler with different connection. 8sound pressure level meter: the sound level meter is the most common instrument used in measuring noise sources. a sound level meter works by using a microphone to sense sound pressure, and electronic circuitry to convert the sound pressure to an spl reading. the test parts of the experimental apparatus are shown in figure (4). the following procedure steps were conducted for each experimental session after completing checking for the system: 1test one, two, and three spherical silencer in series connection is shown in figure (5a). 2test one, two, and three spherical silencer in parallel connection is shown in figure (5b). 3test one, two, and three cylindrical silencer in series connection figure (6a). 4test one, two, and three cylindrical silencer in parallel connection figure (6b). repeat the experimental procedure for every case, by changing frequency from 50 to 600 hz step 50 hz. 4results and discussion for every case, the values of tl and tc are analyzed graphically due to the frequency. the experimental results are the recorded values of transmission losses (tl) and to find values of transmission coefficient ( . the values of tl and tc are analyzed graphically due to the frequency. as shown from the figures, in most cases, there is no differences between the values of tl and tc at low frequencies(50-200) hz because the effect of noise for reactive muffler is obvious at frequencies more than theses values. figures (7 and 8) represent results for spherical silencers in series connection for the one, two, and three. the results show that the transmission losses (tl) for two silencers connection in series are better during the all range of frequency comparison with the one and three silencers. in the tl curve can be noticed the tl peaks at the frequency (350 hz) . figures (9 and 10) represent transmission losses and transmission coefficient for spherical silencer parallel connection. the result show that the three silencers in parallel connection have al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 been dramatically reduced the noise. it is interesting to note that the acoustical performance of the three silencers in parallel connection is better than the two silencers under a same frequency range. in the tl curve can be noticed the tl peaks at the high frequency (350 hz). the values of tl and tc are analyzed graphically due to the frequency. figures (11and 12) represent results for cylindrical silencers in series connection for the one, two, and three. also the results show that the transmission losses (tl) for two silencers connection in series are better during the all range of frequency comparison with the one and three silencers. in the tl curve can be noticed the tl peaks happened at the frequency range between (500-600) hz. figures (13and14) are show transmission losses and transmission coefficient for cylindrical silencer parallel connection. the result also shows that the three silencers in parallel connection are better than the two and one silencers under a same frequency range. in the tl curve can be noticed the tl peaks happened at the frequency range between (200-400) hz. the values of tl and tc are calculated by using equs. (3and4) for cylindrical muffler, where figures (15 and 16) represent theoretical results for cylindrical silencers in series connection for the one, two, and three. figures (17 and 18) show theoretical results for spherical silencer. also theoretical results show that the transmission losses (tl) for silencers connection in parallel are better during the all range of frequency comparison with the series silencer connections. in the tl curve can be noticed the tl peaks happened at the frequency range between (300-350) hz. all the rustles show that the parallel connection is best than the series connection. 5conclusions this paper shows that the parametric optimization along with connection optimization produces well result in the reactive silencers optimization. the study has the following conclusions:  two silencers connection in series is better than one and three silencers.  in spherical silencers the tl peaks were happened at the frequency(350) hz.  three silencers in parallel connection are better than the two and one silencer.  in cylindrical silencers the tl is greater than spherical silencer for the same connections. 6refrences  beranek, l.l. & ver, i.l. noise and vibration control engineering, john wiley & sons inc., 1992.  harris, c.m. "hand-book of noise control", mc graw-hill book company, 1979.  lenzi, a. and barbieri, r., “the study of reactive silencers by shape and parametric optimization techniques”, applied acoustics 72, p.142-150, 2011. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711  min-chie chiu, “shape optimization of multi-chamber mufflers with plug-inlet tube on a venting process by genetic algorithms”, applied acoustics 71, 495–505, 2010.  muna s. kassim, muthana k. al-doory, and ehsan s. al-ameen " experimental investigation for the effect of inlet & outlet pipe lengths on noise attenuation in a muffler ", engineering and development journal, 2012.  munjal ml. acoustics of ducts and mufflers. new york:john wiley, 1987.  muthana k. al-doory, muna s. kassim & ehsan s. m. al-ameen " the effect of orifice shape on noise reduction in a muffler experimentally" proceedings of the 5 th scientific conference, waset university, wasit, iraq december, 13-14, 2011.  rahman, m., sharmin, t., hassan, a f m e., and al nur, m., " design and construction of a muffler for engine exhaust noise reduction" proceedings of the international conference on mechanical engineering icme2005), 2830, 2005.  zhaorong zhang, “simulation analysis of acoustic attenuation performance for different shape of an expansion chamber silencer”, second international conference on information and computing science, p.10-12, 2009. figure (1): schematic diagram of test rig arrangement. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (2a): photo of spherical silencer figure (2b): inside of spherical silencer figure (3a): photo of cylindrical silencer figure (3b): inside of cylindrical silencer 12 cm 0 cm 12 cm 0 cm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (4): photo of the test parts. figure (5a): photo of spherical silencers in series connection. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (5b): photo of spherical silencers in parallel connection. figure (6a): photo of cylindrical silencers in series connection. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (6b): photo of cylindrical silencers in parallel connection. figure (7): transmission losses of spherical silencers in series connection. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (8) transmission coefficient of spherical silencers in series connection. figure (9): transmission losses of spherical silencers in parallel connection. figure (10): transmission coefficient of spherical silencers in parallel connection al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (11): transmission losses of cylindrical silencers in series connection. figure (12): transmission coefficient of cylindrical silencers in series connection. figure (13:) transmission losses of cylindrical silencers in parallel connection. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 717 figure (14): transmission coefficient of cylindrical silencers in parallel connection. figure (15) transmission losses of cylindrical silencers in series connection. figure (16): transmission coefficient of cylindrical silencers in series connection. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 711 figure (17): transmission losses of cylindrical silencers in parallel connection. figure (18): transmission coefficient of cylindrical silencers in parallel connection. 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 تصميم وتصنيع آلة تغليف الجدران علي حسن حمزة مدرس مساعد الكلية التقنية / المسيب. -المستخلص : عنليرة ب رومجرقت نتيجرة الجقجرة لرة نيكقنيكيرة تطرر ارقب ق توالتي لم األبنية صنيع آلة تغليف جدران تان فكرة وكلفرة اقر كفرقتة افضر ب, ( بالطرق قضر ) نثر البنواد التغليف النتعقرف عليهق في الوق الج جدرانال تغليف النمطررط وضررع و . الننفرر شررم لا نهررقرةالترري تعتنررد علرر الناررتمدنة اليرروم و الوجيرردة ن قرنررة بقلطري ررة اليدويررة فروال هقعنليرة تصرنيع ارتمدم فريوأ. (1)الشكك في النوضجةوضوع البجث عل ضوت فكرة االلة ن يتصنينال الهيقك وهو ا نواصفق نيكقنيكية ننقابة لتصنيع ( dinاب النواصفة االلنقنية ج ck30كربوني نوع ) الهيكررر جنيرررعت دم فرررييررر لتكررروين نجنرررع لجرررقنيطري رررة لجرررقم ال ررروئ الكهربرررق ي بترررم ربرررط بعرررال اجررر ات االلرررة . . ( 2)الر ياي لآللة وكنق نوضح في الشك -: متاز باالتيت اآللةهذه و . نن العقن الننف لتفكيك في نوقع العن دون الجقجة ال مبرة او نهقرة التركيب وا اهلة 1 نن قب الشم دون الجقجة ال ناقعدة . وننقولتهق قمفيفة الو ن بجيث ياه جنله 2 اقتصقديق نن جيث التصنيع أو االاتمدام . غير نكلفة 3نرقدة التغليرف ارتعنق نمتلفرة بقننتمبة نن جردران االلة في تغليف ناقجق ه هالتطبي العنلي الاتمدام تمو -( عل كال نن : قعنوديق او اف يتنوجهق عدم ااتوات تلك الجدران )تأثير درااة تم و ( . بالطق ) ال الداملي ( .االانن والرن والنقتنن مليط وهي الكنية النطلوبة نن النقدة النقل ة )1 ليف .ال نن الال م لتنفي عنلية التغ2 ) دينقر / نتر نربع ( . ن قاهلعنلية التغليف الكلفة الكلية 3 , الكفاءة والكلفة .لحام القوس الكهربائي فوالذ كربوني , آلة تغليف , تصنيع , -: رئيسيةكلمات 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 design and manufacturing of equipment wall coverin ali hassan hamza assistant lecturer college of technology / musayyib key words: equipment covering , manufacturing , carbonic steel , arc welding , efficiency and cost . abstract: the idea of manufacturing came as a result of the high need of mechanical equipment make the covering process of the walls with better efficiency and minimum cost in comparison with manual method which is used today and depend on the achieving worker efficiency. the required designs had been established on the view point of the above equipment as shown in figure (1) . and it had been made from carbonic steel type ( ck30 according to the germany specification din). and using electric arc welding (arc) been linked to some parts of the equipment with each other to form the main structure shown in figure (2).which their advantage is: 1-easy to install and reinstall at the working field with no need to experience and knowhow. 2-light weight where it will be easy to raise and transported by the operator with no help. 3-not costly economically by the manufacturing and using side. the practically application of this equipment had been achieved by covering of selected areas for different walls using (ceramic) internal covering material. the study include the effect of non-plain these walls ( it’s undulation vertical and horizontal ) for the followings: 1-the required filling material (a mixture of cement, sand and water ). 2-the required covering achieving time. 3-the total cost measured by (dinar per square meter). -: ألمقدمة للتطررررررور الهق رررررر فرررررري نجررررررق العنررررررران عقلنيررررررق ومقصررررررة فرررررري قطررررررقع ا ارررررركقن نتيجررررررة التواررررررع الارررررركقني نظرررررررا ةالنت ايرررررررد وأارررررررقليب البنرررررررقت النمتلفرررررررة والتررررررري ال تكرررررررقد أ نرجلرررررررة نرررررررن نراجلررررررره أن تملرررررررو نرررررررن اارررررررتمدام أ لررررررر عليهررررق نررررن تجاررررينق لنررررق كررررقن عليرررره ينكررررن ال ررررو انرررره لرررروال امتررررراع ا لررررة ونررررق أدمرررر .[1] بنمتلررررف أنواعهررررق ونررررررررع امتررررررررراع ا ال وتنرررررررروع لنجررررررررقال وت دهررررررررر كنررررررررق هررررررررو عليرررررررره اليرررررررروم نررررررررن الننكررررررررن أن تت رررررررردم تلررررررررك ا االجتيقجررررررق فليهررررررق فرررررري النجررررررقال النمتلفررررررة لررررررم ياررررررتطع نررررررق نوجررررررود ننهررررررق اررررررد الجقجررررررة نتيجررررررة الاررررررتجداث للنبررررقني االنهررررقت الاررررطجيق ) ومقصررررة أعنرررر. [2] ة أمرررررر ظهررررر نررررع تطررررور نجررررق العنرررررانأعنررررق فنشررررق ي ....الرررررر ( الارررررريرانيك نثرررررر الججررررررر , الجرررررردران دامليررررررق أو مقرجيررررررق بقاررررررتمدام نررررررواد نتنوعررررررة نثرررررر أكاررررررقت ولظهررررررررور نشررررررررقك نصررررررررقجبة لهررررررررده ا عنررررررررق أصرررررررربح ل انررررررررق البجررررررررث عررررررررن ا ال الترررررررري تنقاررررررررب هرررررررر ه .[3] -: تياألاالجتيقجق وتاهم في ج لبعال نشقكلهق النتنثلة في نتر نربع (. / دينقرارتفقع تكقليف أجور العن ن درة ) 1 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 .فطقلة نن التنفي 2 اليدوية . عل األاقليب قا نتقجية العتنقده انمفقال -3 .كثرة التقلف نن النواد الناتمدنة 4 .[4] ف الفردية اليدوية للعقن النن التبقين في جودة التنفي بين نوقع وأمر العتنقد ن يقئ النهقرة5 -المواد وطرائق العم : الداملرررررة فرررري تصرررررنيع االلرررررة جارررررب ال يقارررررق النبينرررررة فررررريجررررر ات االتجضرررررير ترررررم -: المكككككواد المسكككككتخدمة 1 . (2)كنق في الشك التي يتم تجنيعهق ( و ck30نن الفوال الكربوني نوع ) (1)الجدو في نوقع نع بعضهق يتم تجنيعهق جيث نفردة توأج ا لجقنيةااللة تتكون نن نجنعق -طريقة العم :2 .االلة نصيب لتالعن , جل ق التثبي , العنود الر ياي )النكونة نن هقااتمدم في عنلية ربط اج اتف د النجنعق الثقنوية أنق نق االج ات النف ( طري ة لجقم ال وئ الكهربق ي .والصقنولة ناقند االرتكق وك لك الصفيجة العليق النتكونة ردة وا في نوقع العن ق اللجقنية ققعدة االرتكق واللولب ( فيتم توصيلهق نع النجنع, ) صفيجة االانقد نن الجدران التجربة التطبي ية لعنلية تغليف نف . و (2)وكنق نوضح في الشك لآللة الهيك الر ياي تنصيبلت . / و ارة ا اكقن واألعنقرالعقنة شركة الننصور في فجدر النشقريع التقبعة فل بقاتمدام ه ه االلة الناتمدنة كنية نقدة الجشونن كال عل ) تنوجه اف يق او عنوديق ( الجدار ااتواتعدم -لدرااة تأثير : .الكلفة الكليةو ألتنفي ننو -المدروسة : عوام ال -االتي :معد استهالك المواد المستخدمة بعملية التغليف والمتمثلة ب1الفراغ بين قطع (جشو) نلئالناتمدنة في ( و نقدة الجشو النتكونة نن) االانن , الرن , النقت أ آليق بقاتمدام جهق بينهنق ويتم التجكم بكنيتهق نن مال الايطرة عل الناقفة النتروكة ..[5]الايرانيك والجدار ام . ( 2) وبنعد فجنقلي = ,( 2في الشك ) والنوضح( النرف نع ا لة leveling deviceاالاتوات ) بوااطة . جيث أنكن الجصو عل اات رار نابي لتلك الناقفة اف يق او عنوديق الجدار بن دار تنوجوتأثرهق لعنلية تأثيره عل الكلفة النهق ية فيهق و لت لي الهدر الجقص ) الجشو( نقدةونن ثم تجديد كنية جهق االاتوات . التغليف 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 نابة التقلف ننهق فثنقت العن ويتطلب األنر ت لي ( وهي بإشكق ون قاق عديدة )الايرانيك تغليفال نقدة ب في عنلية التغليف ة طع الايرانيك الناتمدنل االبعقد ال يقايةلك بتجديد طو شوط العن لآللة وف ويتم انيك الناتمدنة في عنلية عدد وأبعقد قطع الاير . فن التجكم بناقجة الشوط العقن لة التغليف يعتند عل[6] . (1) كنق في العالقة و التغليف -:جيث فن a / وت قئ )نتر نربع ( .ناقجة الشوط العقن لآللة / n . ) عدد قطع الايرانيك في الشوط الواجد ) قطعة m / ك الواجدة ) نتر نربع / ال طعة (ناقجة قطعة الايراني . الال م لتغليف جدار نعين نن جقص ضرب ال نن الال م لتنفي شوط يتم اجتاقب ال نن -: ألتنفيذزمن 2 . (2وكنق في العالقة ) .الجدار لك دد االشواط الال نة لتغليف واجد نضروبق بع -جيث ان : t ة( ./ نن تغليف الجدار ) دقي t . )نن تنفي الشوط الواجد ) دقي ة / s جدار .كقن ال/ عدد االشواط الال نة لتغليف ( .3) عالقةال كنق فيتم اجتاقب ا نتقجية العنلية لآللة و -: اإلنتاجية3 -حيث إن : p = اقعة(نربع / )نتر ن قاه ا نتقجية . a = نربع(. )نتر قاهناقجة التغليف ن t = اقعة(.ن قئ نن التنفي( -: ةالنتائج والمناقش -:االتييتضح أدنقه ( 4 , 3 , 2الجداو ) النتق ج العنلية النبينة في نالجظة نن 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 نع ا نتقجية الفعلية, الكلفة فجنقلي نن التنفي , نن عل كال الننف تأثير نوع العن (2)يبين الجدو 1فن ااتمدام ا لة في تنفي عنلية التغليف يؤد فل يقدة عنلية أظهر النتق ج ال أثبو ناقجة التغليف . ل وك لك يؤد ف ( %48 %51 ) نن مال ت لي نن التنفي بنابة ( ( %208 %194 ا نتقجية بنابة .الناتمدنة في الوق الجقضر ي جقلة ااتمدام الطري ة اليدويةعنق هو عليه ف ( %50) الكلفة بن دار مفال الناتمدنة في التجربة العنلية الجدران) تنوج اف ي او عنود ( ننق ج اتواتا عدمتأثير (3)يبين الجدو 2 في تركيب الايرانيكفن نن كال نن عنليةج الأظهر النتق . جيثعنلية التغليف نفردا تنفي عل نن تأثير بيننق كقن , الجدار عدم ااتواتتفكيك ا لة بعد االنتهقت نن شوط العن لن تتأثر بدرجة وك لك ا لة نقدة ) ب نلئ الفراغعنلية نن و تنصيب ا لة في نوقع العن عنلية نن ل الجدار واضح ع عدم ااتواتدرجة ( %27) وصل ال ( بيننق aالجدار) لننو ج( %22) في نن التنفي بن دارنابة ال يقدة جيث كقن (الجشو . (4)كنق في العالقة و ( .cلننو ج ) -حيث ان : r / . نابة ال يقدة في نن التنفي tp .نن عنلية نجددة لننو ج نعين / ttنن العنليق ل لك الننو ج . / أجنقلي عنلية تغليف ناقجة ) واجد نتر نربع ( نن جدران نمتلفة نن جيث ااتوات نتق جقيم (4) يبين الجدو 3 ( %36%30) يقدة في نن التنفي بن دارفن هنقلك عنليةجيث أظهر النتق ج ال. المقضعة للتغليف ااطجهق ( (%35 %32فنق ا نتقجية فتنمفال بنابة ( %22%44) جشو تكون بن داردة بكنية نقدة البيننق نابة ال يق ن اطح الجدار النطلوب تغليفه ياهم في ت لي ن ااتواتنن نالجظة الناب الن وية للنتق ج أعاله يتبين فن عن وبقلتقلي ت لي ا نتقجية وهدا يؤد بقلنتيجة النهق ية فل تاريع وتيرة النن التنفي وكنية نقدة الجشو وي يد . الكلفة تم ااتمدانه في تصنيع االلة نوضوع الكربوني ال لفوال النعيقرية والفعلية لنواصفق ال (5)يبين الجدو 4 البجث . -االستنتاجات : نع اتمدام االلة في تغليف الجدران بقلن قرنة التي انكن الجصو عليهق نن انن نالجظة النتق ج العنلية ان يتضح (لجد االن لعدم وجود الة نيكقنيكية ت وم بهده العنلية) وهي الطري ة الوجيدة للن قرنة ري ة اليدوية الط -االتي :نن مال افض نوضوع البجث هي كفقتة االلة 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 .( %48--%51انمفقال نن تنفي عنلية التغليف بنابة ) اد ال 1 (. %50نابة )الكلفة الكلية لعنلية التغليف ب مفض 2 .( ( %194 %208بنابة الطققة االنتقجية رفع 3 افضلية ااتمدام االلة في عنلية تغليف الجدران ن قرنة نع الطري ة اليدوية الناتمدنة كفقتة و وهي نؤشرا عل . )هي الوجيدة اليوم ( ادرصالم ترجنة ربيح نجند ندير. 2002 ألنعنقر وا نشقتعنقصر التصنيم " , توفر رنا أ [1] 2002. جقنعة ال قهرة / " تصنيم الننشآ "د. نشهور غنيم . [2] .2892نرك بجوث نواد البنقت / . عنقن ." نواد البنقت " روجي شريف . [3] [4] donald p. coduto " foundation design: principles and practices (2nd edition) , jul 10, 2000. [5] eighteenth arab-international cement conference and exhibition ." multi-component cements / new types of cements " no. march 2012. [6] h. muller, i. lippert and e. lippert. "ceramic technical college bunzlau." keram. z. 39, (5), 321, 1987. [7] j.h.bungey and s.g. millard / testing of concrete in structures.2009 . [8] r.i. gilbert and n.c. mickleborough "design of pre-stressed concrete" . 2004 [9] r.c.hibbeler. structural analysis 5th. edition. 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 00 . ( اجزاء االلة 1) لجدو ا الكنية االبعقد )نلم.( اام الج ت 2 2850 ×80 ×40 العنود الر ياي 1 6 1100×100×3 صفيجة اانقد 2 12 110×50×5 جل ة تثبي 3 1 1000×60×5 ققعدة ااتنقد 4 2 40×20×5 ناند ققعدة ارتكق 5 m20×150 2 لولب نعقيرة 6 m20 2 صقنولة 7 2 100×50×3 جة عليقصفي 8 . واحدةتغليف ( يوضح االجزاء المطلوبة لتصنيع آلة 1* الجدو ) متغيرات نوع العم .( (2 الجدو ناقجة نوع العن التغليف (m². )a فجنقلي نن التغليف t ( min.) الكلفة c (dinar/m².) ا نتقجية p (m²./hr) manual 1 35 --45 10000 1.33 --1.71 machine 1 18 --– 22 5000 2.77 -3.33 (.1m²مفردات زمن التنفيذ لنماذج الجداران المغلفة لمساحة ) (3) الجدو ننق ج الجدار نن التنفي ) دقي ة ( a b c 6 5 4 عنلية تنصب االلة 6 6 6 عنلية تركيب الايرانيك في االلة 6 5 4 نلية نلئ الفراغ ) الجشو (ع 4 4 4 عنلية تفكيك االلة 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 المستخدمة . ان( لنماذج الجدار 1m²متغيرات عملية تغليف مساحة )( 4) جدو النتغيرا ننو ج الجدار اجنقلي نن التنفي t (min.) كنية النقدة النقل ة m (kg.) ا نتقجية (m²./hr. )p a 18 24 3.03 b 20 36 2.85 c 22 48 2.77 . المستخدم في تصنيع االلة موضوع البحث) قياسية ,فعلية ( مواصفات الفوالذ ( 5)جدو fe% ni% mo% cr% mo% mn% , si% c% ال ينة alloys (aisi) rem. max. 0.4 max. 0.1 max. 0.4 max. 0.1 max. 0.4 —065 0.3 1 1030 القياسية 98.19 0.34 0.1 4 0.25 0.15 0.60 0.3 3 الفعلية steel ck30 ( mat. no.1,1178, din ck30 , aisi 1030 ) may be welded by all methods . in heavy section it is advisable to pre-heat at ( 150 to 26c°) and post-heat at (540 to 650 c°) for welding . 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 . المخطط التصميمي لآللة( 1الشكل ) 1000 mm. 3000mm. 450mm. 50mm. 100m m. 450mm. 200mm m. موضع قطع السيراميك 3102لسنة -الثالثالمجلد السادس، العدد جلة القادسيه للعلوم الهندسيهم 06 . تجميع الهيكل الرئيسي لآللة ( 2الشكل ) . العمود الرئيسي حلقات تثبيت عايرة االرتفاعبرغي م صفيحة عليا صفيحة اسناد السيراميك قاعدة ارتكاز السيراميك يمثل السقف يمثل األرض آلة استواء افقي آلة استواء عمودي مسند قاعدة ارتكاز لحام الحلقة study of traffic safety evaluation and improvements at unsignalized intersection al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 natural convection heat transfer enhancement in air filled rectangular enclosures with portirions angam fadel abid abstract natural convection of an air filled partitioned rectangular enclosure is studied numerically. top and bottom of the enclosure are adiabatic; the two vertical walls are isothermal. two perfectly insulated baffles were attached to its horizontal walls at symmetric position. the flow is assumed to be two-dimensional. the discretized equations were solved by finite volume method.the study was performed for different values of rayleigh numbers ra ( 84 1010  ), baffles length and position ( bb sl , )(0-0.8,0.2-0.8) and aspect ratios of the enclosure. the effect of ( )bl and )( bs on heat transfer and flow were addressed.two different patterns of the flow field were observed. the first is the flow circulate in single primary vortex strangled by two trapped fluids and the second pattern is the flow consist of two vortexes separated by one trapped fluid.with increasing of ra heat transfer rate(nusselt number)increased and for increasing baffles length the heat transfer rate decreases. the numerical results of the values of average nusselt number and maximum absolute stream function have been confirmed by comparing it with similar previous works using the same boundary conditions. good agreement was obtained. key words: natural convection, heat transfer, rectangular enclosure, insulated baffles انتقال الحراره بالحمل الطبیعي في وسط مغلق مقسم مستطیل الشكل مملؤ بالهواء انغام فاضل عبد مدرس مساعد كلیة الهندسه جامعة الكوفه وجزالم تــم اجــراء دراســه عددیــه النتقــال الحــراره بالحمــل الطبیعــي فــي وســط مغلــق مقــسم مــستطیل الــشكل مملــؤ تـم اضـافة .ه مـسخنه الـى درجـات حراریـه مختلفـه ومنتظمـه والجـدران االفقیـه معزولـهتكون الجدران العمودی.بالهواء افترض ان الجریان ثنائي البعد وتم حل المعادالت .حاجزین معزولین تماما الى الجدران االفقیه بمسافات متساویه 84(هذه الدراسه انجـزت لقـیم مختلفـه مـن عـدد رایلـي .باستخدام طریقة الحجوم المحدده 1010 (،)bl،bs (0وقــد لــوحظ وجــود .تــم دراســة تــاثیر التغیــر فــي طــول و موقــع الحــواجز علــى معــدل انتقــال الحــراره).(0.8,0.2-0.8 متـــــان االول ان الجریـــــان یـــــدور بدوامـــــه منفـــــرده والنمـــــوذج الثـــــاني یتكـــــون مـــــن دو،نوعـــــان مـــــن نمـــــاذج الجریـــــان وزیــادة طــول الحــواجز ،بینــت الدراســه ان الزیــاده فــي عــدد رایلــي تــسبب زیــاده فــي معــدل انتقــال الحــراره.منفــصلتان تم مقارنة النتائج العددیه لعدد نسلت واكبـر قیمـه مطلقـه لدالـة الجریـان مـع .تسبب نقصان في معدل انتقال الحراره .ب جدا لهذه البحوثالدراسات السابقه ووجد ان الحل العددي الحالي مقار nomenclature angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012192 a aspect ratio [a=h/l] g gravitational acceleration [ 2/ sm ] h enclosure height [m] l length of enclosure [m] l dimensionless baffle length[l/h] nu local nusselt number p pressure [pa] p dimensionless pressure[p/h] pr prandtl number(0.7) [  / α ] ra rayleigh nmber [gβh3(th−tc)/αν ] s baffle position s dimensionless baffle position[s/h] uu ss , source terms t temperature [k] u, v components of the fluid velocity [m/s] u, v dimensionless velocity components cu characteristic velocityu = )( ch tthg  x, y coordinate axis [m] x, y dimensionless axes greek symbols α thermal diffusion coefficient [ sm /2 ] β volumetric thermal expansion coefficient[ 1k ] ρ fluid density [ 3/ mkg ]  dimensionless temperature[ ch c tt tt    ]  kinematic viscosity [ sm /2 ]  stream function φ general scalar dependent variable γ diffusion coeffecient subscripts b related to baffle c cold h hot average e.wt.b enclosure without baffle introdution over the past twenty years, a revolution in electronics has been taken place. natural convection cooling of components attached to printed circuit boards, which are placed vertically and horizontally in an enclosure, is currently of great interest to the microelectronics industry. natural convection cooling is desirable because it doesn’t require energy source, such as a forced air fan and it is maintenance free and safe. cavities and enclosures with no obstructions in them have been studied in the past few decades. the current interest has now shifted to complex cavities and enclosures containing obstruction or a partition which has important implications in many branches of engineering particularly in microelectronics fabrication industry [kandaswamy and hakeem, 2007]. natural convection in an air filled enclosure with vertical walls that are heated and cooled while its horizontal walls are adiabatic has received a great consideration because many of the industrial applications employ this concept as a prototype. noticeable examples include heating and ventilating of rooms,solar collector systems electronic cooling devices and cooling of nuclear reactors. in many applications for some reasons, the cavity is partitioned by attaching baffles to its natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 193 vertical and (or) to its horizontal walls. recentl studies of heat transfer and fluid flow characteristics of the partitioned enclosure have come under scrutiny both numerically and experimentally [ambarta and daimaruya, 2006]. in the literature, various studies have been published on the mechanism of natural convection in differentially heated cavities and enclosures with different geometrical parameters and boundary conditions [anikumar and jilani, 2008]. altaç and kurtul [alta and kurtul, 2007] numerically studied 2d natural convection in tilted rectangular enclosures with a vertically situated hot plate placed at the center. the plate was very thin and isothermal. the enclosure was cooled from a vertical wall only. rayleigh numbers ranged from 105 to 106. the flow pattern and temperature distribution were analyzed, and steady-state plate-surface-averaged nusselt numbers were correlated. altac and seda [altac and.seda, 2009] studied an air filled rectangular enclosure containing an isothermal plate which was cooled from lateral wall while other three sides were insulated. the plate and the cold walls were mainted at constant temperatures. the governing equations were solved using finite volume method coupled with simple algorithm. rayleigh is varied from 75 10*510 to .they found that with increasing rayleigh the heat transfer rates increased and for increasing plate length the heat transfer rate decreased by about 25%. zimmerman and acharya [zimmerman, 1987] studied numerically the natural convection heat transfer in a cavity with perfectly conducting horizontal end walls and finitely conducting baffles. results were obtained at lower rayleigh numbers, and no flow separation in front of partial divider was noted. acharya and jetli [acharya and. jetli, 1990] had numerically investigated the heat transfer and flow patterns in a partially divided differentially heated square box. rayleigh numbers studied were in the range of 65 1010  . the flow was weak in this stratified region and a tendency for flow separation behind the divider was observed .bajorek and llyod [bajorek and .lloyd, 1982] studied experimentally a differentially heated air filled square partitioned cavity for rayleigh numbers(1.25*105-2.16*106).the insulated baffle was attached to horizontal walls at positions in the middle. non dimensional baffle length was 0.25.the effect of the baffle positions was not considered. it was found that the baffles significantly influenced the heat transfer rate and the average nusselt numbers reduced to approximately 15% compared to the non partitioned cavity. jetli et al. [jelt iand.acharya, 1986] studied numerically a differentially heated air filled square partitioned cavity for a rayleigh numbers ( 410 3.55*105) with three different combinations of the baffle positions. non dimensional baffles length was fixed at 0.33.the results clearly demonstrated that the baffles positions had a significant effect on the heat transfer and flow characteristics of the fluid. for all baffles locations, the average nusselt number was smaller than the corresponding value in a cavity without baffle. ambarita et al. [ambarta and daimaruya 2006] studied numerically a differentially heated square cavity, which is formed by horizontal adiabatic walls and vertical isothermal walls. two perfectly insulated baffles were attached to its horizontal walls at symmetric position. the study covers rayleigh in the range(104-108), non dimensional thin baffles length bl are (0.6-0.8),non dimensional baffle positions bs from(0.2-0.8).it was found that nu is an increasing function of ra, a decreasing one of baffle length and strongly depends on bs .dagtekin and oztop [dagtekin, and. oztop2001] numerically studied the natural convection heat transfer and fluid flow of two heated partitions in a rectangular enclosure for rayleigh number range of 104-106. the partitions were attached to the bottom wall; the length and the location were varied while the enclosure was cooled from two walls. nakhi and chamkha [dagtekin, and. oztop2001] numerically investigated natural convection heat transfer from an inclined heat fin attached to the hot wall of a square enclosure. in the present work we study natural convection in an air filled partitioned rectangular enclosure is studied. the enclosure is differentially heated and the baffles were attached to top and bottom walls. the baffles are thin , perfectly insulated and non dimensional baffles length bl are varies from (0 to 0.8) and non dimensional baffles positions bs from(0.2-0.8).the objective of this paper is to make clear the effects of the long baffles and aspect ratios of the enclosure on the flow, temperature fields and heat transfer. angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012194 mathematical formulation consider a two-dimensional rectangular enclosure as shown in figure 1. the top and bottom walls of the enclosure are adiabatic and the two vertical walls have different uniform temperatures. left and right walls are isothermal at ht and ct respectively. two-thin baffles with non dimensional length perfectly insulated are attached to the top and the bottom walls. the positions of the top baffle from the right wall and the bottom baffle from the left wall are the same. the cartesian coordinates(x, y) with the corresponding velocity components (u, v) are as indicated in figure 1.the gravity g acts normal to the y-direction. the flow is assumed to be laminar, two-dimensional, steady state condition. under boussinesq approximation the compressibility, radiation, heat exchange and dissipations are negligible. all of the thermal properties are constant except density in the buoyancy force. based upon the previous assumptions and introducing the following dimensionless variables [kandaswamy and hakeem, 2007]:                ch c c cc tt tt u p p u v v u u u h y y   , , , h x x 2 (1) the governing equations for the present study will take the following forms [kandaswamy and, hakeem2007]: continuity: 0      y v x u (1a) x-momentum                          2 2 2 21 y u x u x p y u v x u u   (2) y-momentum )( 1 2 2 2 2 cttg y v x v y p y v v x v u                            (3) energy equation                       2 2 2 2 y t x t y t v x t u  (4) the dimensionless forms of the governing equations will be as follow; 0      y v x u (5)                                                2 2 2 2 pr y u x u x p y u v x u u (6) pr ²² pr 22 ra y v x v y p y v v x v u                                                (7) natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 195                                        22 ²² yxy v x u  (8) the boundary conditions in dimensionless form are: 1,0  vu on the left wall 0,0  vu on the right wall 0,0     y vu  on the top and bottom walls 0 vu on the baffles where the velocity components are defined as: x v y u        , (9) the local nusselt number nu is defined by [ambarta, kishinami and daimaruya2006]: dx x nu ch x )( / 0       (10) resulting in the average nusselt number as: ynudun  1 0 (11) numerical method numerical solutions for the governing equations with the associated boundary conditions are obtained using finite-volume techniques. a general conservation equation form common to all governing equations may be given in cartesian form as follow [patankar and spalding, 1972]   s xx u x ii i i                (12) where the general scalar φ stands for any one of the dependent variables under consideration. the diffusion coeffecient γ and the source term s in cartesian form are listed below for each governing equation [versteeg and malalasekera, 1995] ; continuity equation 0,0,1  s momentum equation in x-direction x p su    ,pr, momentum equation in y-direction pr,pr, ra x p sv     energy equation angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012196 0,1,  s the numerical solution of the governing equations will be made according to the finite volume method to transform the governing equations from partial differential form to discrete algebraic form; the staggered grid system is used. this method is based on principle of dividing the flow field to a number of volume elements, each one of them is called (control volume), after that a discretization process is carried out by integrating the general conservation equation (12) over a control volume element, where this equation will be as follow; ussnnwweepp saaaaa  (13) where; psnwep saaaaa  (14) the source coefficients )&( pu ss represent the source terms of the discrete equation and their values for each governing equation which are listed as follow: for the continuity equation      0 0 p u s s (15) for x-momentum         0p u s x p s (16) for y-momentum          0 pr p u s ra y p s  (17) for energy equation      0 0 p u s s (18) the discretized algebraic equations are solved by the simple algorithm. relaxation factors of about (0.01–0.1) are used for all dependent variables, convergence is measured in terms of the maximum change in each variable during iteration under the following condition: 5 , , , 1 ., 10      ji n ji ji n ji n ji   where  stands for either ,,vu and n denotes the iteration step. in order to determine the proper grid size for this study, a grid independence test is conducted for the values of ra ( 864 10,10,10 ) and at bl =0.6, 4.0bs .five different grid densities 40*40,60*60,80*80,100*100,120*120 are taken. the maximum value of absolute stream function and average nu are selected as the monitoring variables for the grid independence study. the results are presented in fig.(2), and comparison of predicted .max and un values among five different cases suggests that the three grid distributions 80*80,100*100,120*120 gives nearly natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 197 identical results. considering both the accuracy and the computational time the following calculations were all performed with a 80*80 grid system. results and discussions natural convection at low prandtl number (0.7), corresponding to an air is investigated numerically in the presence of a two perfectly insulated baffles which are attached to horizontal walls of the rectangular enclosure at symmetric positions and at different aspect ratios(a=1,2). the computations are carried out for a wide range of rayleigh number varying from 104 to 108.the results are depicted as streamlines, isotherms plots and other figures. the rate of heat transfer across the enclosure is calculated in terms of average nusselt number un . figure 3 shows the streamlines and isotherms for square enclosure without baffles at different ra. figure 3 (a) shows that the streamlines, it can be seen that the flow consists of single cell filling the entire enclosure and causing circulatory motion of the fluid because of buoyancy effects. the rise of fluid due to heating on the left wall and consequent falling of the fluid on the right wall creates a clockwise rotating vortex referred to as the primary vortex. as ra increases the streamlines become closer to the vertical walls, this suggests that the flow moves faster as natural convection is intensified. the maximum absolute value of stream function can be viewed as a measure of the intensity of natural convection in the enclosure. as (ra) increases the maximum absolute value of the stream function increases. this means, that the intensity of natural convection in the enclosure increases as ra increases. figure 3 (b) represents the isotherms, as ra increases the temperature levels will increase gradually where the hot fluid rises up along the left-hand side hot wall and descends along the right-hand side cold wall because of the buoyancy effect [altac and.seda, 2009]. flow and temperature fields for the square enclosure with baffles are presented in figure 4. in this figure, the non-dimensional baffle positions bs are taken (0.2-0.6), and the non-dimensional baffle length bl varied from 0.2 to 0.6 at different ra. the bottom baffle is on the hot side and the top baffle is on the cold side of the enclosure. it can be seen the flow field can be divided into two patterns. the first pattern is the fluid circulates and creates a large clockwise primary vortex strangled by the baffles [ambarta, kishinami, daimaruya, saitoh, takahashi and suzuki, 2006], [altac and.seda, 2009]. the second pattern is the fluid separated into two different vortexes. this pattern can be seen when ra increases. as the intensity of natural convection increases, the primary vortex starts dividing into two vortex, cold vortex and hot vortex in order to satisfy the continuity. these two vortices are separated by one trapped fluid which is stagnant between the two baffles. figure 4 (a) and (b) shows streamlines at low ra (104) and bl <0.5 the natural convection creates a single vortex in the entire enclosure. these vortexes are strangled by two trapped fluids, the hot trapped fluid exists between the bottom baffle and the hot wall and the cold trapped fluid exist between top baffle and cold wall. the primary vortex starts dividing into two vortex, cold vortex and hot vortex, when bl and bs >0.5. these two vortexes are separated by one trapped fluid which is stagnant between the two baffles because natural convection is too weak to make the trapped fluids moving. when ra increases(106) and bl <0.5, the streamlines become more closer to the vertical wall, producing strong boundary layer effects on the isothermal walls, and the flow remains unicellular. when bl >0.5 and bs <0.5, there are two vortices in the enclosure and the trapped fluid exists between the two baffles, because when ra increases the natural convection increases and make the trapped fluid moving faster. for bs >0.5,the two vortexes are combine to become a primary vortex because the spaces between each baffle and the nearest wall are wide enough, and some of the trapped fluid exists in hot and cold side. the corresponding isothermal contours are presented in figure 4 (c) and (d).the isotherms shows slight deviation from the pure conduction case with the contour lines becoming skewed at low ra[ambarta,.kishinami,.daimaruya,.saitoh,.takahashi,and.suzuki, 2006]. at high ra the isotherms becomes almost horizontal between the two baffles and dense of this lines are established angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012198 at the bottom left and top right of the enclosure due to faster moving fluid and the separation of the primary vortex. figure 5 (a) and (b) represent the streamlines for a=2, bs (0.2-0.6) and bl (0.2-0.6) at different ra.at low ra( 410 ),the main circulation encircles the enclosure formation a single vortex likes square enclosure, the only difference is in the dimensions of the trapped fluid and the maximum value of absolute stream function. with increasing ra and when bl and bs <0.5 the inner roll within the main vortex between the baffles develops and gains strength and will distorted. when bl >0.5 the unicellular circulation inside the main vortex is broken up into two rolls and concentration of streamlines near the baffles because the natural convection is enough to make all of the trapped fluids flowing. when bs >0.5 the flow consists of one vortex strangled by two trapped fluids, hot trapped fluid exists between the top baffle and the hot wall and the cold trapped fluid exists between the bottom baffle and the cold wall. figure 5 (c) and (d) shows the contour lines of the temperature distribution. at low ra, the isotherms are almost straight lines like square enclosure. the increase in ra results in a significant horizontal temperature gradient between the baffles and producing closer isotherms in the trapped fluid because the temperature difference on vortex areas is small due to fluid circulation but it is high on the trapped fluid. the trapped fluids blocks the convection heat transfer from hot wall to cold wall and conduction heat transfer are only considered. for square enclosure, the average nu is plotted in figure 6 as a function of ra and for different bl (0.3, 0.7) and bs (0.2, 0.4, 0.6, 0.8). the average nusselt number un for the enclosure without baffle is also presented in this figure by a dashed line as a reference. this figure shows the appearance of un lines pattern is similar with each other, the only differences are in the quantity of un .this is because the length of the baffles changes the quantity of un .with increasing baffle length the average nu decreases for all values of ra, because the length of trapped fluid between the two baffles is decreases. the ( un ) increases with increasing ra due to increased temperature gradients along the hot and cold walls. ( un ) for case bs <0.5 are lower then the cases when bs >0.5. this is because un is trapped fluid’s dimension dependent that increases as its width increases but decreases as its length increases .fig(6.a)shows the case with bl (0.3). for bs (0.2), un is decreased by 22.7% at ra= 410 and by 36.3% at ra= 810 , the average is 29.5%. for bs (0.6) at ra= 410 , un is decreased by 31.4% and is 27.1% at ra= 810 ,the average is 29.2%. these values suggest that the case with bs (0.2) blocks the heat transfer rate more effectively than with bs (0.6) because the width of the trapped fluid becomes smaller. for 7.0bl and bs =0.2(fig.(6.b), at ra= 410 , un is decreased by 33.4% and at ra= 810 ,it is 48.5%, the average 40.9%,while at bs (0.6), at ra= 410 un is decreased by 35.2% and at ra= 810 ,it is 31%, the average 33.1%.these values suggest when increasing baffles length blocks the heat transfer rate more effectively, because the uncovered vertical walls are decreased with increasing baffles length, and longer uncovered areas reveal higher un ,since the heat transfer rate correlates with natural convection on the uncovered vertical walls. figure 7 represents the variation of un fo a=2 as a function of ra and for different parameters. for 3.0bl and bs =0.2(figure 7 (a)), un is decreased by 18.8% at ra= 410 , and at ra= 810 , it is 43.9%, the average 11.4%,while at bs (0.6), at ra= 410 un is decreased by 22.8% and at ra= 810 ,it is 4.2%, the average 13.5%. for 7.0bl , un is decreased by 53.1% for bs =0.2,and ra= 410 ,and is 41.6% for ra= 810 .for bs =0.6, un is decreased by 36.3% for ra= 410 ,and 25.8% for ra= 810 .figure 8 (a) represent the variation of nu with bl at bs (0.2) it can be seen with increasing the baffle length the average nu is decreased. figure 8 (b) represent the variation of un with bs at bl (0.6).it can be seen with increasing bs , the average nusselt number will be natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 199 increasing until ( bs =0.6),because the area of the trapped fluid is increasing and un is trapped fluid′s dimension dependent that increases as its width increase. to exhibit the reliability of the presented results, the variation of average nu with ra at ( 6.0bl , bs =0.6,a=1) were compared with ambarita et al.[ ambarta,.kishinami, daimaruya, saitoh, takahashi and.suzuki, 2006] at the same conditions as shown in figure 9 (a), where it is clear the similarity in nu behavior at high ra with mentionable study, but there is small difference between these values because of different grid sizes used and round offs in the computational process. another comparison were made with the same work for maximum absolute stream function as shown in figure 9 (b).the comparison shows a good agreement. conclusions in this study heat transfer enhancement of air filled partitioned rectangular enclosure for various pertinent parameters like baffle length and position, rayleigh number and aspect ratios of the enclosure.the enclosure was performed by vertical isothermal walls and adiabatic horizontal walls. two thin insulated baffles were attached to its horizontal walls at symmetric position. the main conclusions of the present study are: 1-the flow field can be divide into two patterns, the first is the flow circulate and creates a primary vortex strangled by two trapped fluids and the second pattern is the flow consist of two vortexes separated by one trapped fluids. 2-at low ra and ( bb sl , ) <0.5, the flow circulate as a single primary vortex and at high ra and bl >0.5 the flow separated in two vortexes for square enclosure. 3-for rectangular enclosure, at low ra and ( bb sl , )>0.5 the flow consist of two vortexes separated by one trapped fluid, but at high ra the flow consist of primary vortex with inner roll is broken up into two rolls. 4-the average nusselt number increases as rayleigh number increases. 5-as the baffles length bl increases the average nusselt number will be decreased. 6-with increasing the baffles position bs , the average nusselt number increases until ( bs =0.6) references 1-p.kandaswamy, j.lee, a.k.hakeem,"natural convection in a square cavity in the presence of heated plate",nonliner analysis:modeling and control,vol.12,no.,2,203-212,2007. 2-h.ambarta,k.kishinami,m.daimaruya,t.saitoh,h.takahashi,andj.suzuki,"laminar natural convection heat transfer in an air filled square cavity with two insulatedbaffles attached to its horizontal walls",j.thermal science andeng.,vol.,14,no.,3,2006. 3-s.h.anikumar, and g.jilani,"natural convection heat transfer enhancement in a closed cavity with partition utilizing nano fluids",proc.of the world congress on eng.,vol.,ii,july 2-4,2008. 4-z.alta, and o, kurtul , "natural convection in tilted rectangular enclosures with a vertically situated hot plate inside",j. applied thermal engineering,vol. 27, pp.1832–1840, 2007. 5-z.altac, and k.seda,"natral convection heat transfer from a thin horizontal isothermal plate in air filled rectangular enclosures",j. of thermal science and technology, 29, 1, 55-65, 2009. 6-e. zimmerman, s.acharya, “free convection heat transfer in a partially divided vertical enclosure with conducting end walls”, int.j. hmt, vol.30 (2), , pp.319-331, 1987. 7s.acharya, r.jetli, “heat transfer due to buoyancy in a partially divided square box”, int. j. heat mass transfer, 33 (5), pp.931-942,1990. angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012200 8-s.bajorek, and j.lloyd,"expermintal investigation of natural convection in partitioned enclosures",j.heat transfer,104,527-532,1982. 9r.jelti,s.acharya,e.zimmerman"influnce of baffle location on natural convection in a partially divided enclosure"numerical heat transfer,10,521-536,1986. 10-i.dagtekin, and h.f. oztop, "natural convection heat transfer by heated partitions", int. commun heat mass transfer 28, pp. 823-834, 2001. 11b.a-nakhi, anda.j. chamkha., "effect of length and inclination of a thin fin on natural convection in a square enclosure",j. numer heat transfer, part a 50, pp.389407, 2006. 12-patankar and spalding, "a calculation procedure for heat, mass, and momentum transfer in threedimensional parabolic flow," int. j. heat mass transfer, vol. 15, pp. 1787-1805, 1972. 13h. k.versteeg, and w.malalasekera,"an introduction to computational fluid dynamics the finite volumes method", longman group ltd, 1995. natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 201 figure 1 physical model and coordinate system. figure 2 variation of nusselt number and maximum absolute stream function with the number of grid points for different rayleigh number. angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012202 figure 3 streamlines and isothermal plot for natural convection in square enclosure without baffles, a-streamlines, b-isothermal ra=104 y x y x ra=105 y y y y y y y y x x x x x x x x ra=106 5 ra=107 ra=108 natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 203 abcdfigure 4 streamlines and isothermal plot in square enclosure ,a,cra=104,b,d-ra=106:the first column bs =0.2, bl =0.2, second column bs =0.8, bl =0.2,third column bs =0.2, bl =0.6,fourth column bs =0.6, bl =0.6 angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012204 figure 5 streamlines and isothermal plot for a=2 , a,c-ra=104,b,d-ra=106,the first column bs =0.2, bl =0.2, second column bs =0.6, bl =0.2,third column bs =0.2, bl =0.6,fourth column bs =0.6, bl =0.6 natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 205 (a) (b) figure 6 variation of nusselt number with rayleigh number with sb as a parameter for a=1; (a) lb=0.3, (b) lb=0.7 angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012206 (a) (b) figure 7 variation of nusselt number with rayleigh number with sb as a parameter for a=2; (a) lb=0.3, (b) lb=0.7 natural convection heat transfer enhancement in air filled rectangular enclosures with portirions al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012 207 (a) (b) figure 8 variation of nusselt number with lb, sb for a=1; (a) sb=0.2, ra=104, (b) lb=0.6, ra=106 angam fadel abid al-qadisiya journal for engineering sciences, vol. 5, no. 2, 191-208, year 2012208 (a) (b) figure 9 comparison of average nusselt number and maximum absolute stream function with ref. [12] 9-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 computer-aided selection of the optimal lot sizing system (cals) farah kamil abd muslim department of mechanics technical institute/ dewanya abstract a lot of works have been done by the researchers to solve lot-sizing problems over the past few decades. many techniques and algorithm have been developed to solve the lot-sizing problems. basically, most of the algorithms are developed either based on heuristic or mathematical approach. since computer-aided has been given attention by the researchers in many areas including production planning, therefore in this paper we implement computer-aided to solve single level lot-sizing problem. five models are developed based on five well known heuristic techniques, which are lot-for-lot (lfl), economic order quantity (eoq), periodic order quantity (poq), part period balancing (ppb) and wagner-within algorithm (ww). the planning period involves in the model is 5 period where demand in the periods are varies but deterministic. the model was developed using visual basic version 5 with access database. results show that when entering the needed inputs through the user interface, which is general inputs and special inputs, the (cals) system selects the suitable lot size technique that gave optimum solution and easy application to the lot-sizing problem. keywords: lot sizing techniques, material requirements planning. )cals( / يب . یة. lfl( حا eoqpoqppbww.( al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ـ . ه access. ) (cals . nomenclature bom = bill of material c = carrying cost per item per unit time. ci = duration for which inventory is carried cals = computer aided lot sizing co = ordering cost d = average demand eoq = economic order quantity epp = economic part period lfl = lot for lot llc = low level code ls = lot size lt = lead time mps = master production schedule mrp = material requirements planning pp = cumulative part-period for period ppb = part period balancing poq = periodic order quantity q = economic order quantity. ri = requirement for period i. s = setup cost per batch sm = silver meal t =ordering interval ww = wagnerwithin 1. introduction lot sizing is an approach used to determine optimum order or production quantity in each period in a planning horizon. it is widely used in material requirement planning system. many lotsizing techniques have been developed and established by the researchers. the developments of lotsizing techniques are basically based on either heuristic approach or mathematical modeling. order quantity (eoq), periodic order quantity (poq), lot-for-lot (lfl) and part period balancing (ppb) are amongst techniques that adopted heuristic approach. meanwhile, wagner-within (ww) is considered mathematical approach in which it was developed based on dynamic programming. this paper will discuss about implementing computerized model to solve lot-sizing problems. the purpose of developing computerized model is to evaluate the performance of computer in solving lot sizing problems and to overcome the difficulties faced by the user in using either heuristic or mathematical approach. 2. literature review this section gives literature review on lot sizing, computer-aided and the research that motivates the author to apply computer-aided in mrp problem of lot sizing. problem in determining the optimum quantities (lot sizes) to order in discrete time periods of a single item over al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 n periods to satisfy a certain demand pattern with the objective to minimize the sum of ordering and carrying cost is a common problem in keeping inventory always in stock. method proposed by (radzi, haron and johari 2006) shows neural network to solve single level lot-sizing problem. three models are developed based on three well known heuristic techniques, which are periodic order quantity (poq), lot-for-lot (lfl) and silver-meal (sm). the model was developed using matlab software. (hoesell & wagelmans 1990) study sensitivity analysis of the incapacitated single level economic lot-sizing problem, which was introduced by wagner and whitin about thirty years ago. (cheng 1989) tested two other well-known non-cost-based heuristics: the lot-for-lot and fixed period requirement rules, and compared with the wagner-within(ww)optimization algorithm the lot-for-lot proves to be an effective rule to use when inventory cost is high. (de matteis 1968) developed simpler algorithm that has been such as by ppb. (saydam & evans 1990) show the relative performances of four popular heuristic against the (ww). (al-juboory 2002) developed computer-aided monitoring of production planning system which was built by means of the relational database technology using visual basic version 5 with access database. (gaafar 2000) applied neural network model in mrp problem of lot sizing. the performance of the model is analyzed and compared to common heuristic method. 3. reasearch methodology 3.1. data preparation: the necessary information for (calst) system are shown in figure (1). they are: erial (bom): for all parent items -times: for all items 3.2. the developed (cals) system: the (cals) system is developed specifically to select the suitable lot size technique that give optimal solution, also it is easy to be applied in lot-sizing problems. the developed system can perform several functions as depicted in figure (1). each function interface with the other functions. 3.2.1. user interface: the user interface main module plays a key role in various (calst) system activities, by providing the possibility of accessing any part of the system. user interface is the communication mechanism between the user and other modules of the system. when the user enters the needed inputs through the user interface, the system selects the suitable techniques relative to the input. 3.2.2. common database: the database must contain high level information about the product, because in such system we need common database that supports the user interface. this database consists of: 1. item master database. the item master database (also called part master database or inventory record database) contains a record for every item in the company's inventory products, assemblies, components, materials, and supplies. a typical list of the data stored for each item is represented in table (1). we will describe the elements on the list. aitem number: the item number is a unique number that identifies the item and is the key to record in the file. bprojected inventory on hand: the projected inventory on hand is the current inventory of the item. clead times: the lead-time is the time between placing an order and receiving it. dscheduled receipt: scheduled receipt is the previously released orders, either purchased from the market or manufactured. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 eordering cost: the cost of order release. fholding cost: the cost of carrying. 2. bill of material database. the bill of material database specifies what materials, components, assemblies, and subassemblies are used in making the product. we will describe the elements on the list. alow level code (llc): level refers to where an item fits in the product structure. the final product is at level 0. the components used directly in making the final products are at level 1. components used in making level 1 items are at level 2, and so forth. bquantity per assembly: it is the required number of a part in each assembly. 3.2.3. lot sizing module: lot sizing function is the process of determining the quantities in which order are placed. this module consists of several lot sizing techniques. therefore, depending on the type of inputs that the user enter, the system has been designed and developed to suggest the best lot sizing technique that correspond to these inputs as shown in figure (2). 1. lfl function: it is the name given to the method that orders exactly what is required in each period. it should produce units only as needed with no safety stock and no anticipation of future orders. lot for lot is frequently used for expensive items and high discontinuous demand item. the lfl function is built as shown in figure (3). {net requirements}= {gross requirements} {on-hand inv.} {scheduled receipts} gross requirements: the anticipated future usage of the item (mps). scheduled receipts: previously released orders, either purchased or manufactured. current: on-hand inventory (end-item, subassembly, or processed parts). lot-sizing (ls) rule: how the jobs will be sized in order to minimize the cost. planned lead-time: the time between placing an order and to receiving it. planned order receipts: purchase or manufactured items that must be available at the beginning of a timer bucket. planned order released: planned orders after offsetting using lead-time. 2. eoq function: eoq module assumes that the demand is constant. in the eoq formula, annual demand is replaced with average demand per period. a weakness of the eoq technique is that large quantities of units, which are not immediately required, are carried in stock. the order quantity is specified by the economic order formula: q = 2sd/ c (1) where: q= economic order quantity. s= setup cost per batch. d= average demand for item per unit time. c=carrying cost per item per unit time. the eoq function is built as shown in figure (4). 3. poq function: the periodic order quantity (poq) technique is based on the same thinking as the eoq method. for the eoq technique the order quantity is constant while ordering interval varies. however, for the poq model the ordering interval is constant while the order quantity various, thus: t=q/d (2) where: t=ordering interval. q= economic order quantity. d= average demand for item per unit time. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 the poq function is built as shown in figure (5). 4. ppb function: ppb is a more dynamic approach to balance setup and holding cost, ppb uses additional information by changing the lot size to reflect requirements of the next lot size in the future. it divides demand requirements into order periods such that ordering and holding cost are balanced. although the technique does not guarantee an optimum solution, it does produce a very good solution. the procedure for ppb is as follows: calculate an economic part period or epp, for the problem. this value is expressed as a ratio between ordering and holding cost. it is used as a measuring tool to determine when to place an order. epp = ordering cost/ carrying cost = co/cc (3) this technique selects the order quantity at which the part period cost matches the epp value, most closely ppi= ppi-1 + (ri*ci) (4) where: pp: cumulative part-period for period i. ri: requirement for period i. ci: duration for which inventory is carried. the ppb function is built as shown in figure (6). 5. ww function: the wagner-within procedure is a dynamic programming model that adds some complexity to the lot-size computation. wagner-within begins with the first period in the planning horizon and evaluates all possible combinations of orders to meet demand in that period. it then proceeds to period two and does the same, and so on, until the optimal method for meeting demand in all periods is determined. the ww function is built as shown in figure (7). 4. results and discussion to show the validity of our approach and for the purpose of completeness, we applied this system in state company of rubber industries. this company provided us the necessary information such as (production plan, ordering and carrying cost for product, operation time for all the production processes, and the inventory information). the company produces several types of products. product (x) is being selected which consists of (21) part. planned order is released at the same time for all the parts. the monthly quantity of product (x) are (1716) for september 2010. the researcher selected part number (1) of product (x) to test the (cals) system as follow: by entering the following data(current year, month, monthly quantity, days per period, and holiday at each period), and by using the bill of material database that consist of(part number, quantity per assembly, and low level code). the cost database provide the system (ordering cost and carrying cost). the inventory database provide the system (scheduled receipts, projected on hand and lead time).the results are master production schedule table from the following equations: quantity per day= monthly quantity / number of work days during the month = 1716 / 26= 66 quantity per period= quantity per day number of work days per period quantity per period1 = 66 2 = 132 then the system calculate the lot sizing techniques as follow: 1lot-for-lot: { gross requirements }= {quantity per period} { quantity per assembly } { gross requirements for period1}= 132 1 =132 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 {net requirements}= {gross requirements} {on-hand inventory} {scheduled receipts} {net requirements for period1}= 132 0 0=132 {planned order receipts}={net requirements}=132 total cost= ordering cost for all period+ carrying cost for all period = (8072.4 5) + 0 = 40362 $ 2economic order quantity: { gross requirements }= {quantity per period} { quantity per assembly } { gross requirements for period1}= 132 1 =132 average demand for item per unit time(d)=sum{ gross requirements for all periods}/ number of periods= (132+396+396+396+396)/ 5=343.2 economic order quantity (q )= 2 ordering cost per batch (s average demand for item per unit time(d) / carrying cost per item per unit time(c) economic order quantity (q )for period1= (2 8072.4 343.2) / 16.1448=586 {net requirements}= {gross requirements} {on-hand inventory} {scheduled receipts} {net requirements for period1}= 132 0 0=132 {planned order receipts}={ economic order quantity }=586 total cost= ordering cost for all period+ carrying cost for all period = (8072.4 4) + (7329.7392+ 7329.7392+ 936.3984+0+9202.536)= 57088.0128 $ 3periodic order quantity: { gross requirements }= {quantity per period} { quantity per assembly } { gross requirements for period1}= 132 1 =132 average demand for item per unit time(d)=sum{ gross requirements for all periods}/ number of periods= (132+396+396+396+396)/ 5=343.2 economic order quantity (q )= 2 ordering cost per batch (s average demand for item per unit time(d) / carrying cost per item per unit time(c) economic order quantity (q) for period1= (2 8072.4 343.2) / 16.1448=586 ordering interval(t)=economic order quantity(q)/average demand for item per unit time(d) =586/343.2=2 {net requirements}= {gross requirements} {on-hand inventory} {scheduled receipts} {net requirements for period1}= 132 0 0=132 {planned order receipts}={ planned order receipts for pereiod1+ planned order receipts for pereiod2 }=132+396= 528 total cost= ordering cost for all period+ carrying cost for all period = (8072.4 3) + (6393.3408 2)= 37003.8816 $ 4part-period balancing: { gross requirements }= {quantity per period} { quantity per assembly } { gross requirements for period1}= 132 1 =132 economic part period(epp)=ordering cost(co)/carrying cost(cc)= 8072.4/16.1448 =500 cumulative part-period for period 1 (pp1)= cumulative part-period for period 0 (pp0) + {requirement for period 1 (r1)* duration for which inventory is carried (c1)} cumulative part-period for period1(pp1)=0-(132 0)=0 (is this closet match to epp) ? no {prospective lot size for period 1 }={net requirements for period 1 + net requirements for period 0 }=132-0=132 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 total cost= ordering cost for all period+ carrying cost for all period = (8072.4 4) + (10655.568+4262.2272+6393.3408)= 53600.736$ 5wagner-within: { gross requirements }= {quantity per period} { quantity per assembly } {gross requirements for period1}= 132 1 =132 {net requirements}= {gross requirements} {on-hand inventory} {scheduled receipts} {net requirements for period1}= 132 0 0=132 period alternatives ordering cost carrying cost total cost optimal policy 1 (1) 8072.4 0 8072.4 (1) after calculate all period the optimal policy is (1,2,3,4,5) {planned order receipts}=sum{net requirements}=132+396+396+396+396=1716 total cost= ordering cost for all period+ carrying cost for all period = (8072.4) + (25573.363+19180.022+12786.6811+6393.3408)= 72005.808$ from the above techniques the system selects the best technique (periodic order quantity) that have minimum cost the application of the proposed system is introduced here. figure (8) shows the proposed input frame and the result ( master production schedule mps) depend upon database in figure (9),(10),(11) to calculate the lot sizing technique for the five techniques as shows in figures (12),(13),(14),(15),(16). figure (17) shows the output of the system and the selected suitable lot sizing technique depend on minimum cost. 4. conclusions in this paper, we construct a software program that selects the suitable lot sizing technique depend upon scientific bases. the (cals) system provides with bill of material database, inventory database, and cost database that can be updated at any time. this model can be applied to solve lot sizing problems faster and easier because it can give optimum solution and posses certain characteristic that make the model more effective to be used. from the (cals) system we conclude the following: lot-for-lot techniques order just what is required for production based on net requirements and it may not always be feasible. if setup costs are high, costs may be high as well eoq using average demand and expects a known constant demand and mrp systems often deal with unknown and variable demand part-period balancing tries to make the setup costs as close to the carrying costs as possible. fixed order quantity method constant lot sizes wagner-whitin referencees [1] al-juboory, f.k., "computer aided monitoring of production planning", m.sc. thesis, baghdad, 2002. [2] cheng, t.c.e., " a comparative study of some non-cost-based lot-sizing heuristics", computers ind. engng. vol. 16, no.1, pp87-96,1989, pergamon press plc. [3] de matteis, j.j. and mendoza, a.g., 1968. an economic lot sizing technique. ibm systems journal, 7: 30al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 [4] gaafar, l.k. and choueiki, m.h., 2000, "a neural network model for solving the lot sizing problem", the international journal of management science, omega. 28:175-184. [5] hoesel, stan van, and wagelmans, albert, " sensitivity analysis of the economic lot-sizing problem" or 238-90 november 1990. [6] radzi,nor haizan mohamed, haron, habibollah, and johari ,tuan irdawati tuan, " lot sizing using neural network approach" school of mathematical sciences, universiti sains malaysia, penang, june 13-15, 2006 [7] saydam, cem& evans, james r., "a comparative performance analysis of the wagner-within algorithm and lot-sizing heuristics", computers ind. engng. vol. 18, no.1, pp.9193,1990, pergamon press plc. table (3): lot sizing report perioditem: llc: ls: lt: current 1 2 3 4 5 6 7 8 gross requirements scheduled receipts projected inventory balance net requirements planned order receipts planned order released item no. projected on hand lead time scheduled receipt ordering cost holding cost serial no. part no. llc quantity per assembly table (1): item master file table (2): bill of material file al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ww function start enter your inputs ppb function poq function eoq function lfl function suitable lot sizing technique figure (2): flowchart of the lot sizing module item master database bill of material database figure (1): system architecture user interface lot sizing module common database lot sizing report al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 start for i = 0 4 input the lead time calculate the gross requirements calculate projected on hand calculate net requirements calculate planned order release is i < 4 lot sizing report no yesnext i bill of material databaseinventory database figure (3): flowchart of the lfl function calculate planned order receipts start for i = 0 4 input the lead time calculate the gross requirements calculate average demand calculate optimal quantity calculate net requirements (nr) is nr<= 4 lot sizing report no yes next i bill of material database cost database planned order receipts (por1)=0 por1= optimal quantity calculate projected on hand yes no is i < 4 inventory database calculate planned order release (por2) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 start for i = 0 4 input the lead time calculate the gross requirements calculate average demand calculate optimal quantity calculate optimal ordering interval lot sizing report next i bill of material database cost database figure (5): flowchart of the poq function calculate planned order receipts calculate net requirements calculate projected on hand yes no is i < 4 inventory database calculate planned order release al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 start for i = 0 4 input the lead time calculate the gross requirements calculate economic part-period (epp) calculate projected on hand calculate net requirements lot sizing report next i bill of material database cost database figure (6): flowchart of the ppb function calculate part-period (cumulative) calculate prospective part-period calculate carried in inventory yes no is i < 4 inventory database is ppc >epp yes no calculate planned order receipts calculate planned order release al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 start for i = 0 4 input the lead time calculate the gross requirements calculate projected on hand calculate net requirements lot sizing report next i bill of material database cost database figure (7): flowchart of the ww function select least total cost probability calculate carrying cost calculate probability yes no is j < 4 inventory database is i < 4 yes no calculate planned order receipts calculate planned order release calculate ordering cost for j = 0 4 next j al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (8): the proposed input frame figure (9): bill of material database frame figure (9): cost database frame figure (10): cost database frame al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (11): inventory database frame figure (12): lot for lot technique frame al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (14) periodic order quantity technique frame figure (13) economic order quantity technique frame al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (15) part period balancing technique frame figure (16) wagner -within algorithm technique frame al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (17) select the suitable lot size technique frame article al-qadisiyah journal for engineering sciences 12 (2019) 056–060 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: kaka2013331@gmail.com (bariq a.h. al-qaisi) https://doi.org/10.30772/qjes.v12i1576 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. effect of pure aluminum in reduction of silica from sediments in iraqitigris bariq a.h. al-qaisi a* and sami. i.j. al-rubaiey a dept. production eng. & metallurgy, university of technology , baghdad, iraq a r t i c l e i n f o article history: received 03 april 2019 received in revised form 15 may 2019 accepted 19 may 2019 keywords: tigris river sediments pyrometallurgy hydrometallurgy silic, and silicon a b s t r a c t this work was carried out on sediments in the iraqitigris river within the city of baghdad. three locations were taken from the tigris river. the first is at the entrance to baghdad city (al-muthanna bridge), the second is in central baghdad (adhamiya) and the third is at the end of baghdad (diyala jisr). the specimens were taken from the banks of the tigris river at 1.5 meters from the edge of the water and a depth of 2 meters. sediments formed mainly from silica, with concentrations between 59 66%. therefore, the study focused on extracting the pure silicon element from these sediments. the extraction process of silicon from the sediments was performed in two stages. the first is pyrometallurgy stage, in which the reduction of silica was done by mixing pure aluminum powder with sediments at different mixing ratio (1:1, 1.5:1 and 2:1) sediments/aluminum and at temperatures (900, 950 and 1000)° c. the second stage was hydrometallurgy (leaching process), this process was carried out by using different concentrations (3,4 and 5)m of sulfuric acid to obtain silicon element with purity 98. 9%. the results show that the efficiency of extraction silicon from sediments of the tigris river is greater than (88%). © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the sediments are formed on the banks of the rivers and at riverbed as a result of drift of the soil with the movement of water, in addition to the effect of streams and small rivers flowing into the main river [1]. the sediments are taken from the banks of tigris river which contain various compounds such as (sio2, cao, mgo, fe2o3, tio2, al2o3, p2o5, and k2o) at different concentrations. the source of sediments in tigris river come from several areas, the most important one as anatolia plateau in turkey: also tigris tributaries continue as the source of sediments in the tigris river in iraqi territory such khabur, great zab, little zab ,diyala river and adhaim river [1]. the sediments vary in tigris river depending on the quality of the water and affected by different pollutants and type of soil and effect of dayala river on these sediments [2, 3, 4]. the synthesis of high purity silicon from natural substances has been performed by several researchers, using metals like mg, ca, al or c as reducing agents [5,6]. sadique [7] extracted high purity silicon (99.1% purity) from the waste of silica fume (sf). he reached to 99.1% si by using pyrometallurgical process .the best temperature for reduction was (750850)°c at 2:1 mixing ratio of mg/sf. jehad & jasim [8] studied the extraction of silicon with a high purity of 99% by using iraqi starting http://qu.edu.iq/ mailto:kaka2013331@gmail.com https://doi.org/10.30772/qjes.v12i bariq a.h. al-qaisi and sami. i.j. al-rubaiey /al-qadisiyah journal for engineering sciences 12 (2019) 056–060 57 materials (quartzite rock, plant coal) via electric arc furnace at 1500 c̊ . mishra et al. [9] produced polycrystalline silicon from amorphous silica obtained from rice-husk white ash by using calcium at the reduction temperature equaled to 720 c̊ .the final purity of silicon was 99.9% after acid leaching with concentrated hno3 and hf . onojah, a. [10] studied the extraction of silicon from rice husk ash and natural quartz by using magnesium powder however the two sources of silica gave silicon purities in the range of 97-98%. this study focuses on extracting pure silicon element from sediments in iraqi-tigris river which contain silica for percentage (59 – 66)% 2. experimental work 2.1. sampling preparations the specimens were taken from three locations at tigris river in baghdad city. the first is at the entrance to baghdad city (al-muthanna bridge), the second is in central baghdad (adhamiya) and the third is at the end of baghdad (diyala jisr). the specimens were taken from the banks of the tigris river at 1.5 m from the edge of the water and a depth of 2 m at three different locations along the tigris river within baghdad city. which are;  al muthanna bridge  al-adhamiyah  jisr diyala the samples were taken by 10 kg from each mentioned location, in depth of 2 m. these samples were taken using steelmold, the samples then dried at 100˚c for 4hrs. this process was achieved by using a bender oven. 2.2. chemical analysis chemical analysis of the river-sediments was carried out by using x-ray fluorescence (xrf) at the university of baghdad / iraqigerman laboratory as shown in tables 1,2 and 3. table 1. x-ray fluorescence (xrf) at the al-muthanna bridge compounds concentration % sio2 59.974 cao 20.421 al2o3 8.035 fe2o3 4.94 k2o 1.447 p2o5 0.702 mgo 3.255 tio2 0.739 table 2. x-ray fluorescence (xrf) at al-adhamiya location compounds concentration % sio2 59.29 cao 18.17 al2o3 8.739 fe2o3 5,848 k2o 1.523 p2o5 0.688 mgo 3.835 tio2 0.752 others 0.165 table 3. x-ray fluorescence (xrf) at jisr diyala location compounds concentration% sio2 66.007 cao 16.26 al2o3 7.70 fe2o3 4.24 k2o 1.400 p2o5 0.702 mgo 2.54 tio2 0.662 other 0.078 2.3. grinding and sieving processes these processes were accomplished to obtain particles with a size equal to 63 µm by using ball mill machine for grinding time of 1hr.the speed of the ball milling was 300 rpm. auto sieve shaker device at a specified range 53-710 µm was used for grinding process. 2.4. washing process (primary leaching) the samples are washing by using hydrochloric acid at 10% concentration for removal some metal oxides such as (mgo, cao ) and increases the silica ratio [11,12]. this process was done by a magnetic stirrer device for 80 ˚c at 2 hrs with a rotation speed of 500rpm and solid-liquid ratios (14). after each experience, the sample was filtered and dried in an oven at 100 ̊ c for 2 hr. the following equations illustrate the process of dissolving some of the impurities [13,14]. 𝐶𝑎𝑂 + 2𝐻𝐶𝑙 = 𝐶𝑎𝐶𝑙2 + 𝐻2𝑂 (1) 𝑀𝑔𝑂 + 2𝐻𝐶𝑙 = 𝑀𝑔𝐶𝑙2 + 𝐻2𝑂 (2) 2.5. mixing and pressing processes different ratio of al/sediments were used. these ratios are (1:1, 1.5:1 , 2:1) the specimens were compressed using compression a die with a diameter of 3 cm, the applied load was 20 ton for 1 min. 2.6. reduction process the reduction process was carried out in carbolite furnace (type cwf12/13, england) at temperatures 900, 950 ,1000 °c for 2 hrs, the specimens were tightly covered in steel crucible for dimensions (11 cm diameter, and 15 cm length ) to full the crucible. the cover was supplied with value allow for following for argon gas flow. all specimens were tested by atomic absorption spectrometry, x-ray diffraction analysis test was done onetime for each reduction temperature. 2.7. leaching process the leaching process was done to remove impurities in the reduction process by using sulfuric acid at 3, 4 and 5 m and leaching temperature 100 °c for 4 hrs and solid to liquid ratio of 1:6 via using heating mantle device. the insoluble residue was separated from the solution by vacuum pump using filtration paper. then the filtered cake was washed with distilled water several times and then dried in an oven at 100 °c for 1hr. 2.8. x-ray diffraction analysis to identify the formed compounds after reduction x-ray test was done on machine bruker. the test was accomplished under the following parameters: voltage 40 kv , current 30 ma ,1.540 a˚ and scan rate 5-10 ˚deg/min. the test was done at geological department , college of sciences, university of baghdad. 58 bariq a.h. al-qaisi and sami. i.j. al-rubaiey /al-qadisiyah journal for engineering sciences 12 (2019) 056–060 2.9. x-ray fluorescence analysis the purity of extracted silicon powder was tested by using x-ray fluorescence-xrf a type (ametek 2010 germany). the analysis was conducted at the place mentioned above. 3. results and discussion 3.1. washing process (primary leaching) tables 4, 5 and 6 show the increase of silica percentage in samples and decrease the percentage of other compounds after primary leaching process according to x-ray fluorescence analysis compared with tables 1, 2 and 3. table 4. x-ray fluorescence (xrf) at the al-muthanna bridge location compounds concentration % sio2 70.132 cao 13.251 al2o3 9.522 fe2o3 2.651 k2o 0.923 p2o5 0.632 mgo 1.554 tio2 0.519 other 0.816 table 5. x-ray fluorescence (xrf) at the al-adhamiyah location compounds concentration % sio2 68.241 cao 11.216 al2o3 11.631 fe2o3 3.642 k2o 0.989 p2o5 0.423 mgo 2.415 tio2 0.514 others 0.929 table 6. x-ray fluorescence (xrf) at the jisr diyala location compounds concentration % sio2 76.500 cao 8.800 al2o3 10.415 fe2o3 2.145 k2o 0.478 p2o5 0.315 mgo 0.918 tio2 0.211 other 0.218 3.2. reduction process the reduction process by mixing aluminum powder with sediments was carried out to obtain the silicon element from sediments in the tigris river. the compounds present in the products at different temperature were si and some traces like al2o3, and al non-react. in addition to the small amount of non-reacted silica as shown in tables 7, 8 and 9.the mixing aluminum powder with silica in the reduction process, al reacts with silica to produce directly si element and alumina (al2o3),because the aluminum element is more active metal than silicon, according to the following reaction(3)[12,13]. the corresponding x-ray diffraction analysis (xrd) was shown in fig. 1. 3𝑆𝑖𝑂2 + 4𝐴𝑙 = 2𝐴𝑙2𝑂3 + 3𝑆𝑖 (3) figure 1. xrd pattern of reduction products at 1000˚c and ratio of al/sediments 1:1 table 7. effect of al/sediments ratio in reduction process at different temperature at the al muthanna bridge location others % cao % al2o3 % al % sio 2% si % temperature c˚ al/sediments 0.9 5.3 42.2 32.5 0.9 18.2 900 1:1 0.6 6.1 40.2 31.5 0.7 20.9 950 1:1 0.7 3.1 32.9 38.1 0.4 24.8 1000 1:1 0.9 7.3 43.5 32.05 2.7 13.5 900 1.5:1 1.1 7.1 44.1 35.9 1.5 14.9 950 1.5:1 2.2 6.8 43.1 30.6 1.2 16.1 1000 1.5:1 1.8 9.2 40.2 34.4 3.2 11.2 900 2:1 1.2 7.8 41.8 33.1 2.7 13.4 950 2:1 0.6 5.4 38.1 40.5 1.7 13.7 1000 2:1 table 8. effect of al/sediments ratio in reduction process at different temperature at the al-adhamiyah location other% cao % al2o3 % al % sio % si % temperatue c˚ al/sediments 0.9 4.1 41.9 31.2 1.2 20.7 900 1:1 0.6 2.4 38.5 35.6 0.8 22.1 950 1:1 1 3.8 38.9 29.1 1.9 25.3 1000 1:1 0.9 3.2 39.6 38.3 1.6 16.4 900 1.5:1 1.6 2.7 46.8 32.6 1.5 14.8 950 1.5:1 1.4 4.1 40.3 35.1 0.9 18.2 1000 1.5:1 2.4 7.9 37.6 35.3 2.7 14.1 900 2:1 0.5 3.1 40.1 38.1 2.9 15.3 950 2:1 1.5 4.9 38.2 37.4 2.4 15.6 1000 2:1 table 9. effect of al/sediments ratio in reduction process at different temperature at the jisr diyala location other % cao % 3o2al % al % 2sio % si % temperature c˚ al/sediment 1.9 5.5 36.1 35.3 1.6 19.6 900 1:1 2.6 6.8 32.6 33.4 1.2 23.4 950 1:1 1.7 6.1 36.8 26.9 2.4 26.1 1000 1:1 2.9 8.2 40.6 31.2 2.1 15.1 900 1.5:1 1.7 6.5 37.8 35.7 1.5 16.8 950 1.5:1 1.3 6.4 43.7 30.3 1.1 17.2 1000 1.5:1 2.8 8.3 43.5 31.1 1.8 12.5 900 2:1 1.8 9.2 46.9 35.9 0.8 13.7 950 2:1 1.4 7.9 39.5 36.4 1.3 13.5 1000 2:1 bariq a.h. al-qaisi and sami. i.j. al-rubaiey /al-qadisiyah journal for engineering sciences 12 (2019) 056–060 59 a. effect of al/sediments ratio in the reduction process at different temperature: tables 7 , 8 and 9 show the amount of al powder added to sediments at referent mixing ratio 2:1 , 1.5:1 and 1:1 and different temperature 900, 950, 1000 ˚c. the tables show that the amount of al addition have a large effect on the reduction of silica located in sediments. it had been shown that at 1000 ˚c using ratio 1:1 al/sediments, si appears very high amount in three locations (24.8, 25.3, and 26.1) %, whereas at 1000 ˚c ratio with a 2:1 appears small amount in three locations (13.7, 15.6, and 13.5)%. as a result of atomic absorption spectrometry and xrd analysis the percentage of extracted silicon increase when mixing ratio decrease into 1:1 at constant temperature 1000 ˚c [7, 15]. sadique[7]:explain when mixing aluminum or magnesium powder with silica in the reduction process , al or mg can react with silica to produce si element and alumina compound (al2o3), because these elements are more active metal than silicon in ellingham diagram (∆g of aluminum or magnesium ≥ ∆g of silicon). sadique extracted high purity silicon (99.1% purity) from the waste of silica fume (sf) by using magnesium element to reduction of silica (sio2). figure (2) shows si content as a function of al/sediments. the maximum amount of si is achieved at mixing ratio1:1. while the si yield decreases at mixing ratio 2:1 because of non-reaction all silica (sio2) with al powder. figure 2. shows the effect of al/sediments ratio on the silicon yield at three different locations. b. effect of temperature in the reduction process: as shown in tables 7, 8, and 9 that the effect of the temperature on the reduction process of sio2 at a constant ratio of al/sio2 (1:1). according to atomic absorption spectrometry and xrd analysis at 900˚c appears silicon amount in three locations (19.6, 20.7, and 19.6). whereas at high temperature of 1000˚c the silicon amount increases (24.8, 25.3, and 26.1). as a result of atomic absorption spectrometer, the amount of si increases when the temperature increases into 1000˚c at constant mixing ratio (1:1)[7]. figure 3. shows si content as a function of temperature. the maximum amount of si is achieved 1000 ˚c .while the si yield decrease at 900 ˚c figure 3. shows the effect of temperature on silicon percentage at three different locations. 3.3. evaluation of silicon amount production the extraction of silicon process was evaluated since the main purpose of the reduction experiments is to achieve the highest amount of si with high purity. the best condition for this process to obtain the maximum amount of si 26.1 % with high purity 98.9% is achieved at the al/sediments ratio of 1:1 at 1000 c̊. 3.4. hydrometallurgical process hydrometallurgy (leaching process) is a method for obtaining metals from their ores via using different solutions. the pyrometallurgical process for extraction of silicon which was made at different conditions led to the production of various compounds in the reduction process such al2o3. for the purification of the produced silicon, the leaching processes were used. table (10) shows the purification of silicon produced an effect of sulfuric acid on dissolving impurities in the samples and figure (4) shows the edx spectra of the silicon powder. angus l. daniels [16] and paween numluk [17] explained that the aluminum oxide (alumina) react with sulfuric acid at different concentration (3–5)m and forming aluminum sulfate according to following equation(5) at 100 ˚c for 4 hrs, the efficiency of silicon extracted from sediments of tigris river is greater than (88%). 𝐴𝑙2 𝑂3𝐻2𝑂 + 3𝐻2𝑆𝑂4 = 𝐴𝑙2(𝑆𝑂4)3 + 6𝐻2𝑂 (4) table 10. xrf analysis of purification of silicon when temperature =100°c, and time=4hhr samples concentration m si% sio2% al2o3% al-muthanna bridge 3 95.98 0.3 3.72 4 98.9 0.3 0.8 5 93.24 0.4 6.36 adhamiyah 3 96.43 1.4 2.17 4 98.4 1.5 0.1 5 92.76 1.8 5.44 jisr diyala 3 96.92 2 1.08 4 97.3 1.9 0.8 5 93.65 2.1 4.25 12 17 22 27 0.5 1.5 2.5 s i ra ti o al/ sediments jisr diyala location al muthanna bridge location al-adhamiyah location 17 19 21 23 25 27 880 930 980 s i ra ti o temperature ⁰c aladhamiyah location al muthanna bridge location jisr diyala location 60 bariq a.h. al-qaisi and sami. i.j. al-rubaiey /al-qadisiyah journal for engineering sciences 12 (2019) 056–060 figure 4. edx spectra of the as-produced silicon the sem micrograph of the silicon powder as shown in fig. 5. and it can be seen that the shape of particles is random and different size for 4 hrs of leaching time, 100 °c of temperature and (4m) concentration of sulfuric acid. figure 5. the sem micrograph of as-produced silicon the particle size distributions of silicon powder can be seen in fig. 6. shows that approximately 90 %volume of the produced silicon is ≤ 66 µm, 50% of the produced silicon volume ≤ 22µm and 10% volume of the produced silicon is ≤ 5µm. figure 6. the particle size distribution of as-produced silicon 4. conclusions  pure silicon (98,9%) has been successfully produced from sediments of tigris river by pyrometallurgy and hydrometallurgy processes  the reduction process was carried out with attrition of aluminum powder (63 µm particle size) at different ratio ( 2;1, 1.5;1 and 1;1) the best results obtained at ratio 1;1. the effect of al powder is to decrease the reduction temperature of silica  the leaching process carried out by using 4m h2so4 to remove impurities such (al2o3).  the best reduction temperature was found at (1:1) mixing ratio of al/sediments was 1000˚c .  the efficiency of silicon extracted from sediments of tigris river is greater than (88%) references [1] al-bassam, k.s. and al-mukhtar, l.e.,. heavy minerals in sediments of the euphrates river. iraqi bulletin of geology and mining, 4(1) (2008) p. 29 – 41. [2] abdul-hameed m. j. al-obaidy, zahraa zahraw al-janabi, abdul-rahman alkubaisi, distribution of some heavy metals in tigris river middle of iraq, 11(2) (2014). [3] luma abdalalah skben al-abadi, the relative distribution of mica minerals in sand fractions and different soil depths, alqadisiyah journal for engineering sciences, 14(4) (2008) p19. [4] philip, g., mineralogy of recent sediments of tigris and euphrates river and some older detrital deposits jour. sed. pet. 38 (1968) p. 35 – 44. [5] nazma and m. akhter, x–ray diffraction analysis of silicon prepared from rice husk ash, j. mater. sci. 23, 23792381 (1998). [6] l. p. hunt, j. p. dismukes, j. a. amick, a. schei and k. larsen, rice hulls as a raw material for producing silicon, journal of the electrochemical society, 131 (1984) p.16831686. [7] s. elius sadique , production and purification of silicon by magnesiothermic reduction of silica fume, copyright by sarder elius sadique, (2010). [8] jehad. abed taies &amp; jasim h. hassen, production of silicon metal from iraqi sand ,journal of baghdad for science , 11(1) (2014). [9] mishra p., chakraverty a. and banerjee h.d. production and purification of silicon by calcium reduction of rice-husk white ash. journal of materials science, 20 (1985) p.4387-4391. [10] onojah, a., amah, a. n. and ayomanor, b. o, comparative studies of silicon from rice husk ash and natural quartz, american journal of scientific and industrial research, 3(3) (2012) p.146 -149. [11] daroon h. khorsheed , abbas r. ali , heavy minerals distribution in the recent stream sediments of diyala river basin/ northeastern iraq, kirkuk university journal /scientific studies, 10(4) (2015) p.415-438 [12] abdul salam mehdi salih, study of morphological aspects and variation of clay minerals in the recent alluvial sediments of tigres river in sharqat area, tikrit journal of pure science, 15(1) (2009). [13] lide ،david. crc handbook of chemistry and physics, (2000). [14] perry ،r.؛ green d.؛ maloney j. perry's chemical engineers' handbook, (1984). [15] takeshi okutami., utilization of silica in rice hulls as raw materials for silicon semiconductors , journal of metals, materials and minerals, 19 (2) (2009) pp.51-59. [16] angus l. daniels, edison muzenda, recovery of aluminium oxide from flint clay through h2so4 leaching, proceedings of the world congress on engineering, 3 (2012) p1-3, 3p. [17] paweena numluk and aphiruk chaisena, sulfuric acid and ammonium sulfate leaching of alumina from lampang clay, e-journal of chemistry, 9(3) (2012) p. 1364-1372 c p s/e v kev https://www.iasj.net/iasj?func=issues&jid=131&uilanguage=ar https://www.iasj.net/iasj?func=issues&jid=131&uilanguage=ar https://www.iasj.net/iasj?func=issues&jid=131&uilanguage=ar https://www.iasj.net/iasj?func=issues&jid=131&uilanguage=ar chemical and physical effects on engineering properties of gypseous sub-grade soil al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 chemical and physical effects on engineering properties of gypseous sub-grade soil assist. prof. d. abdulaziz a.kifae assistant dean for academic affairs university of al-muthana abstract: using unsuitable material will often result in premature failure of pavement surface and reduction in the ability of pavement to carry the design traffic load. the use of locally natural materials of gypseous soils is necessary to minimize the construction cost. the chemicals and physical tests carried out on this gypsies soil brought from western region of iraq indicates clayey sand particles with 63% gypsum content. the chemical and physical effects on behavior of gypseous soil is studied by leaching using modifying the standard odometer apparatus to be able for testing a large cell of cbr mold under loading values ( 44.5;178;311 )n with different hydraulic gradient values (2;6;10 ) for sixty days. for this purpose, fifty four cbr samples are prepared at a 95% relative to modified aashto compaction. the geotechnical properties of wetting gypseous soils due to the large damages that affect the structures founded and constructed on it. it is observed that the total leaching strain increases, as the surcharge load and hydraulic gradient increase. the results show that the value of cbr increasing with increasing compactive effort (dry density) after leaching gypseous sub grade soil. decreasing voids particles by compactive effort, cause increase cementing materials which bond the soil particles together and increasing the stiffness. this can has an economic effect in pavement design as this increase in cbr% can transfer unsuitable material into suitable sub-grade gypsum soil. keywords: road construction; flexible pavement; sub-grade; gypsum soil; cbr. و الفیزیاوي على الخصائص الهندسیة لتربة أساس الطریقالتأثیر الكیمیاوي الجبسیة د عبد العزیز رسول الكفائي.م.ا جامعة المثنى كلیة الهندسة الخالصة : المسلطة علیه و بالتالي حصول األثقالعدم تحمل إلىاستخدام مواد غیر مالئمة ضمن طبقات الطریق في التصمیم تؤدي الفحوصات إجراءتم لذا .یقلل من كلفة المشروع) التربة الجبسیة( التربة الطبیعیة ضمن موقع التنفیذ استخدام . فشل في الطریق الفیزیائیة و الكیمیائیة لتربة موقع المشروع حسب نظام التصنیف الموحد فكانت من نوع تربة رملیة طینیة و تحتوي على جبس ذه الدراسة تأثیر الخواص الفیزیائیة و الكیمیائیة من خالل غسل التربة تناولت ه.في المنطقة الغربیة من العراق% ٦٣بنسبة al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٠ ( طریق وهي إلنشاءالمناظرة التصمیمیةتحویره لتسلیط األحمالتمالجبسیة باستخدام قالب فحص نسبة التحمل الكالیفورني نموذج و كانت نسبة ٥٤ض تم تحضیر و لهذا الغر ) . ١٠و٦و٢(نیوتن و بتسلیط انحدار مائي قدره ) ١٧٨:٣١١.٥: ٤٤.٥ أظهرت التجارب ضعف .یوم٦٠و الفترة الزمنیة لغسل التربة الجبسیة بحسب االنحدار المائي المذكور هو لغایة % ٩٥الرص أجریت. ةالتربة الجبسیة حین تتعرض للماء و حصول االنهیار فیها خصوصا بزیادة االنحدار الهیدرولیكي و األحمال المسلط أظهرت النتائج زیادة نسبة % ٩٥مقارنة لنسبة التحمل الكالیفورني للتربة الجبسیة بعد الغسل مع مقدار كثافتها الجافة بنسبة رص و بذلك باإلمكان استخدام التربة الطبیعیة في . بعد الغسلالجبسیةلتربةالجافة لكثافةالالتحمل الكالیفورني مع زیادة نسب الرص و .دال من استبدالهابلطبقات الطریقالموقع كأساس introduction: soil is a foundation material for all structures, as highways and airports which may be the form of undisturbed in situ sub-grade material or transported and reworked embankment material. gypsum is one of the soluble salts that can have determined effects on pavement, building and earth structure, (fooksand french, 1977) and (subhi, 1987). when salt bearing soils are subjected to soaking, increases in moisture content can take place causing dissolution of some gypsum. in practice, soaking can take place in different ways such as local shallow wetting, deep local wetting, slow and uniform rise of ground water level. the magnitude and character of such development depend on the type of soil, initial gypsum content, relative amount of leached salts, soil properties, and acting loads, (petrukhin v.p. and boldyrev c.b., 1978). many studies have been made on gypseous soils in iraq because they are covering a wide area of the surface in iraq. the gypseous soils in iraq are distributed in mousel; baigi; tikrit; samarah; north west of baghdad; anna; heat; ramadi; faluja; najef and nassirya,(el-janabi,1995). (al-jumaily ,1994) reported that the effect of gypsum content on soil properties depends upon the amount of salt content, purity of water and its salt concentration, flow velocity and the area of gypsum in contact with water. (al-qaissy, 1989) dealt with a clayey silty soil with ( 1,9,18 and 38%) gypsum content and he found a reduction of 0.15 in specific gravity when the gypsum content increases from 1% to 38 % . (subhi, 1987) found for compacted soil that the maximum density decreases with the increases in gypsum content, while the optimum moisture content decrease or increases with the increase in gypsum content depending on the grain size of the added gypsum. (sheika, 1994) found out that the compression index decreases with the increase in gypsum content due to the increase in the cementing bound of gypsum . ( barazanji ,1984) investigated the infiltration characteristics of al-jazirah gypsum soil .he showed for some soil texture and initial water contents that the infiltration rate increases with the increase in gypsum content. (klein and hurlbut,1985) reported that gypsum contains: 32.6% calcium oxide (cao), 46.5% sulpher trioxide (so3) and 20.9% combined water (h2o).as a result of dehydration gypsum ,the first 1.5 molecules of (h2o) in gypsum are lost relatively continuously between 0oc and about 650c perhaps with only slight changes in the gypsum structure leading to bassanite (caso4.1/2 h2o).at about 700c, the remaining (1/2 h2o) molecule in bassanite is still retained relatively strong ,but at about 950c,it is lost and the structure transforms to that of anhydrite (caso4). (al-mufty ,1997) reported that a large amount of the hydration water molecules are lost if gypsum is heated to (1700c), forming plaster of pairs (bassanite),(caso4.1/2 h2o), but if heating continues to more than (2000c),anhydrite starts to form with the complete loss of hydration water al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧١ anhydrite gypsum (caso4) having specific gravity of (2.96), is heavier than gypsum having specific gravity (2.32).the chemical proportions of gypsum and anhydrite are shown in table (1). (harwood, 1988) pointed out that cements are the crystals, which grow into existing pore space. they may or may not, totally occlude the available pore space. (james and kirkpatrick, 1980) pointed out that the rate of solution of many substances is determined by the rate of transport of soluble components across the boundary layer attached to the dissolved solid. gypsum is sparing soluble salt, its solubility in pure water at 20oc is (2gm/l), but it varies with the presence of other salts and temperature (nashat, 1990). (james and lupton, 1978) carried out several experiments leading to the following general equation governing the solution of soluble minerals: dm/dt = ka(cs-c )m ………………………..(1) t = time, second a= area of gypsum,(m2) cs = the saturation concentration in solution,(kg/l) c = the concentration in solution, (kg/l) m= constant equal (1) for gypsum (caso4.2h2o) k= the solution rate constant, (m/sec) for gypsum and (m4/sec) for anhydrite. they added that the solution rate constant (k) depends on many factors such as: (1) flow velocity of water: the rate of dissolution of gypsum increases linearly as the flow velocity increases from zero to 0.7(m/s). (2) construction of other salts in the soil: the dissolution rate (k) increases with the increase in the concentration of nacl. (3) temperature: they are found that the dissolution rate constant (k) at gypsum increases 3.25 times when the temperature increases from 50c to 230c. ramiah,(1982),found out that the solubility rate of gypsum increases to its maximum when the temperature increases to 40oc then it decreases after that degree. razouki et.al.1994 studied the problems of gypsiferous soil in iraq. they concluded that increasing the applied pressure increases the rate of dissolution of gypsum in water. sheikha 1994 concluded that the rate of total soluble salts is high for lower values of permeability, and low for high values of permeability. the presence of gypsum in a soil, change the original engineering properties of the soil. the foundation problems associated with a collapsible soil have been correlated with collapse potential (cp). clemene and finber, 1981 defined the collapse potential, as follows: cp = ∆ec / (1+eo) = ∆h/ ho ……………….. (2) where: cp = collapse potential ∆ec= change in void ratio upon wetting eo = natural void ratio ∆h = change in height upon wetting ho = initial height al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٢ (lambe and whitman, 1979) reported that the leaching of the salt in the pore fluid of soils containing soluble salts could cause an increase in the permeability. (arutyyan and manukyan ,1982) reported that during the process of dissolution of gypsum from the soil, the permeability increases sharply first but subsequently, decreases then remains constant. (el-rawi,1995) pointed out that such an increase in cbr can have a serious economic effect in pavement design as this increase can transfer unsuitable sub-grade soil after sorb specification (1983) with cbr< 4% into suitable sub-grade soil with cbr > 4% . the purpose of this study is to investigate the chemical and physical effects on the properties of gypsum soil and use it as a suitable subgrade in civil engineering projects. so that ,it is very important to study the characteristics of gypseous soils and their soluble salts constituents in order to understand their behavior under different conditions to have a proper design for foundation and sub grade. materials properties and testing program: the experimental work were carried out on the soil samples taken from al-anbar university at al-ramadi city .samples were taken from (0.75-1.25m) depth below the natural ground surface, and then placed in double nylon bags. the soil samples were taken to the transportation laboratory (al-mustansiria university) for testing. disturbed samples are mixed carefully by hand before conducting any test to be homogeneous. ordinary drinking water is used through this study when preparing the specimens and leaching process. classification tests are performed including physical, chemical tests and x-ray diffraction test. this test was carried out at the state company of geological survey and mining in baghdad. the physical tests include specific gravity, atterberg limits, grain size distribution and water content, figure (1) and table (2). a series of leaching tests is conducted using special equipment by modifying cbr molds, table (2), shows the results of physical and chemical properties of the soil samples used as a sub-grade material. the entire tests were carried out according to astm vol. 04.08, (1989) and b.s, 1377, (1975) standard specifications. specific gravity is determined according to bs 1377, (1975) test no.6b .but instead of distilled water used kerosene because of dissolving action of gypsum by water( head,1980). grain size distribution is determined according to (astm 4221979) but with dry sieving. grain size distribution curve for soil samples is shown in figure (1). in this study, the gypsum content is done according to the method presented by (al-mufty and nashat, 2000): = 4.778 100 …………………… (3) x = gypsum content by weight, % w45oc = weight of sample at 450c w105oc = weight of sample at 1050c the moisture density relationships for both standard and modified compaction tests are obtained using rammer method. all tests were carried out according to (astm d1557-78, method b), (1989) for modified compaction and according to (astm d698-78, method a), (1989) for standard compaction. its appear from figure ( 2) that the maximum modified dry density of 18.5 kn/m3 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٣ takes place at an optimum moisture content of 11.5% ,while the maximum standard dry density of 16.4kn/m3 take place at optimum moisture content of 13.5%. preparation of soils for permeability leaching tests: the cbr mold was used to preparation specimens for permeabilityleaching test with some modifications. the modified mold has an internal diameter of 152.4 mm (6in.) and of 177. 8mm (7in.) height provided with an extension collar 51mm (2in.) in height and a base plate that can be fitted to either end of the mold .a circular spacer metal disk of 150.8 mm diameter and 61.4mm (2.416 in.) height is used to obtain a thickness of compacted specimens that conforms to the thickness 116.43 mm (4.584in.) of specimens in astmd1557-78(1989).manufactured base plate is used additionally to the above parts. tap water is similar to ground water in the field, as water can infiltrate into the aground from irrigation or leaky water pipes. the water supply system to the leaching mold has two elevated cylindrical tanks. each tank has a floating ball. the upper tank is manufactured to be standby and provides the water to the lower tank. the hydraulic gradient is determined at the difference of elevations between the water surface of lower tank and water surface of leaching cbr mold. water supply system is shown in figure (10). the inlet rubber tube of leaching cell is connected with water distributer, which takes the water from the bottom of the lower tank. strength tests: the california bearing ratio test is a comparative measure of the shearing resistance of a soil. it’s the load required to force a standard piston (with an area of 3in2,(1935mm2) the soil at a certain depth, expressed as a percentage of the load required to force the piston at the same depth into a standard sample of crushed stone, (head,1982). the piston moves at a speed of 0.05 in/min (1.27 mm/min). usually penetrations of ( 0.1 or 0.2 ) inches are used to calculate the cbr values , as follows ,[ youder and witczak, (1975); croney,(1977) ; head, (1982 ) ; aashto,(1986) ] . cbr0.1 = ………………….. (4) cbr0.2= …………………… (5) where: p0.1, (p0.2) = load required to force a standard piston [0.1, 0.2] inches into the soil, ps0.1 ,(ps0.2) = load required to force a standard piston [0.1,0.2 ] inches into a standard sample of crushed stone ps0.1= 3000 1bs,( 13.34 kn) and ps 0.2 = 4500 lbs.,(20.01) kn . specimens of soil for the cbr test are molded using the standard cbr mold provided with an extension collar 51 mm (2 in.) in height and a perforated base plate that can be fitted to either ends of the mold. a circular spacer disk made of metal of 150.8 mm diameter and 61.4 mm height is used to obtain a thickness of compacted specimens that conforms to the thickness 116.43 mm of specimens in astm d1557-78(1989). modified proctor compaction is carried out to astm d1557-78 (1989). this will allow the determination of the cbr at 100% relative modified proctor compaction. selected surcharge load 8 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٤ surcharge load during leaching and penetration of sub grade cbr samples are placed to simulate the actual or estimated weight of pavement thickness to be placed on top of sub grade soil (youder and witzak, 1975; wright ,1996). according to aashto (t193) and astm (1983.87), the minimum surcharge load is considered to be (44.5n). following( o, flaherty ,1988), each annular weight (5 1bs) is equivalent to 63.5 mm of flexible pavement thickness. thus, the expected maximum thickness of pavement over the original sub-grade soil may reach 90 cm. for this reason, it was decided to use, (311.5n) surcharge load as the upper limit in this study. accordingly, it was decided to adopt the following surcharge load namely (44.5; 178 and 311.5 n) for this work. the number of blows per layer required to achieve the 95% relative compaction may be affected by the surcharge load. two sets of cbr sample for 311.5n surcharge load are prepared. each set consists of three specimens compacted in five layers with 10, 25 and 56 blows/layer for the first, second and third specimens respectively. the surcharge load is placed on the top of samples in cbr mold and each specimen is then subjected to the penetration test. result and discussions: gypseous soils are strong when dry, but the presence of water decreases the resistance of these soils when they are subjected to soaking or leaching. the main reason of high strength unleached soil contains high gypsum and other salts contents which act as cementing materials between soil particles and they increase the resistance of the soil to collapsing. otherwise, the soil will not be regarded as suitable for sub grade. in order to study the effect of leaching on alanbar gypseous soil, three values of hydraulic gradient are used and various soils samples are prepared at 95% relative modified compaction to be leached under constant head ,(i= 2; 6 and 10) for times, ( t = 4 ;7 ;14 ;30 and 60 ) days leaching periods and under surcharge loads;( 44.5 ;178 and 311.5) n. to get more reliable result, two samples are prepared for each surcharge loads, each leaching period and the test is repeated for each hydraulic gradient. the results of cbr tests are illustrated in figures (3 to 5), it obvious from these figures that the leaching period has a significant effect on the strength of the gypseous soil tests. the increase in leaching period causes a significant decrease in cbr values especially for samples of low surcharge loads. the reason for such behavior of leached gypsum is the high void ratio and the existence of root-hole structure in this soil. the removal of the cementing agents from the soils causes a decrease of the preconsolidation pressure and an increase in the compressibility of the soils. the accumulative leaching strain and dissolved gypsum increase with the increase in leaching period then they remain constant. gypseous soil during leaching process: the term of ''leaching strain'' refers to the strain which caused by gypsum leaching and surcharge loads. the relation between leaching strain and time for modified odometer permeability leaching test at three surcharges loads ; (311.5 ; 178 and 44.5) n. shown in figures (6 to 8). in general, it is found that the leaching strain is very low at the beginning of leaching, and the void ratio increases with increase in the dissolved gypsum until the void ratio reaches a certain value. this behavior may be attributed to the low stress applied to the sample. it is observed that the total leaching strain increases, as the surcharge load and hydraulic gradient increase. this behavior could be related to the soil particles more susceptible to collapse at high surcharge load. the enlargement al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٥ of the voids due to removal of soluble salts and the collapsing of soil structure occurs at the same time. however, in the early stage, the enlargement of the voids is dominant, while the collapsing of soil structure seems to be the major process in the later stage. behavior of gypseous soil after leaching process: the design of flexible pavement thickness requires the cbr value corresponding to that thickness. so that to achieve the correct cbr value should be established a correlation between the surcharge load and strength after leaching gypsum soil. the thickness of the pavement structure depends mainly on the cbr values of the sub grade soil, which in turn depends on the thickness of pavement structure. the thickness of pavement structure above the sub grade is initially unknown. accordingly, it is necessary to establish a relationship between the thickness of pavement structure and the strength; (cbr) values achieved this, by replacing the surcharge load by the corresponding thickness of pavement. the 36 blows per layer are adopted in this work for compaction cbr samples to achieve 95% relative modified aashto compaction. the number of blows per layer required to achieve the 95% relative compaction may be affected by the surcharge load. for this purpose, three surcharge loads are considered (44.5; 178 and 311.5) n for this purpose. cbr values are calculated using eqs. (4 and 5) and governing cbr is plotted versus each of dry density and number of blowes per layer in figure (9) for cases of (44.5, 178 and 311.5) n surcharge loads. it can be shown in figure, (9) that increased the percent of cbr by increasing dry density of gypsum soil after leaching. this could attributed to many reasons : decrease of voids cause increase in values of cohesion c and the angle of internal friction and then strength cementing materials which bond the soil particles together by compactive effort. conclusions : the following conclusions can be obtained from this study: 1.the surcharge loads ( 44.5; 178 and 311.5 ) n have a significant effect on the cbr values ( 12;22 and 40 )% respectively at i = 2 respectively of the tested gypsum soil. hence, an increase in surcharge loads causes an increase in cbr value. 2. the effect of surcharge loads increases with the increase in leaching periods. 5. drop in cbr values (40; 32 and 25) % due to increasing hydraulic gradient values (2; 6 and 10) respectively at surcharge load 311.5 n. 6. the accumulative leaching strain and dissolved gypsum increasing with the increase in leaching period then they remain constant. 7. at the beginning of leaching test, the permeability increases with the increase in leaching period then the value of permeability remains constant. 8. the permeability increases with the increase in hydraulic gradient for the same leaching period. 9 increasing in cbr value can have a serious economic effect in pavement design as this increase can transfer unsuitable sub-grade gypsum soil before leaching into suitable sub-grade soil. 10. increasing compactive effort after leaching gypsies sub grade soil increasing cbr value. 11. after leaching increasing compactive effort increasing cementing of microstructure al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٦ gypsies’ soils. recommendation for future work:1determine effect leading of gypseous soil on strength pavements. 2investigation of microstructure gypseous soil under leading. 3strength in site effect of leading on the mechanical properties of gypsies soil. references: al-jumaly,f.a.(1994):"gypsum and its mechanical effect on engineering properties of soils",journal of arabic university union, vol.19,(in arabic). al-mufty,a.a.(1997):"effect of gypsum dissolution on the mechanical behavior of gypseous solis",ph.d.thesis, department of civil engineering, college of engineering,university of baghdad. al mufty ,a.a and nashat i.h.(2000):''gypsum content determination in gypseous soils and rocks",3rd int. jordanian conference on mining, pp.500-506. al-qaissy,f.f.(1989):"effect of gypsum content and its migration on compressibility and shear strength ",m.sc. thesis,building and construction department,university of technology,baghdad. arutyyan,r.n. and manukyan,a.j.(1982):"prevention of piping deformation in gypseous soils in eevan",soil mechanics and foundation engineering,vol.19,no.4,pp.151-154. barazanji,a.f.(1984):"infiltration rate characteristics of gypsiferous soil in northern iraq (jazirah-area)":m.sc. thesis, irrigation and drainage engineering department college of engineering, university of mosul. clemence,s.p. and finbar,a.o.(1981):"design consideration for collapible soil",proceding of american society of civil engineering asce,journal of geotechnical engineering,vol. 107,no.pp.305-317. croney,d.(1977):"the design and performance of road pavements",transport and road reasearch laboratory,her majestys stationary offfice,london.cited by al-azawi,1998. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٧ el-rawi,n.k.h.(1995):"optimization of design of flexible highway pavement structures",m.sc.thesis,college of engineering,university of baghdad. el-janabi,o.a.(1995):"characteristics of mixtures of gypsiferous soil from tikrit with granular subbase material for subgrade purpose" ,m.sc.thesis,department of civil engineering, college of engineering,university of baghdad. fooks,p.g. and french,w.j.(1977):"soluble salt damage to surfaced road in the middle east", the highway engineer, journal of the institution of highway engineers,vol. 24,no.11,pp.1020.london. james,a.n. and kirkpatrick,i.m.(1980):"design of foundation of dams containing soluble rocks and soils", quarterly of enginrring geology ,vol. 13,pp 189,london. james,a.n. and lupton,a.r.(1978):"gypsum and anhydrite in foundations of hydraulic structures",geotechnique, vol.28,no.3,pp.249-272,london. head,k.h.(1982):"manual of soil laboratory testing ",pentech press limited,london. harwood,g.(1988):"microscopic techniques principles of sedimentary petrography "in the techniques sediment logy, edited by m.tuker,blakwell scientific publications,oxford.cited by alabodi,2003. klein,c.and huribut,c.s.(1985):"manual of mineralogy, after j.d.dana",20th edition,john wiley and sons,new york. nashat, i.h. (1990):''engineering characteristics of some gypseous soils in iraq'', ph.d.thesis, department of civil engineering, college of engineering, university of baghdad. o,flaherty , c.a.(1988):"highwas ",volume 2, "highway engineering ",third edition, edward arnold, london. petrukhin v.p.and boldyrev c.b.," investigation of the deformability of gypsified soils by static load",soil mechanics and foundation engineering,(1978),pp.178-182. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٨ ramiah, b.k (1982): “the effect of chemicals on compressibility and strength of baghdad silty clay", building research center r.d. (70/82) baghdad. razouki, s.s and al-omari ,r.r.; nashat, i.h.razouki ,h.f. and khalid, s.(1994):"the problem of gypsiferous soils in iraq'',proceeding symposium on gypsiferous soils and their effects on structure,nccl,pp.733,baghdad. sheika, a.a. (1994):''the collapsibility of gypseous soil and the effect of leaching on its behavior'', m.sc. thesis, building and construction department, university of technology, baghdad. subhi, h.m.(1987):the properties of salt contaminated soils and their influence on the performance of roads in iraq",ph.d.thesis .queen marry college, university of london . wright,p.h.(1996):"highway engineering '',sixth edition john wiley sons, inc.,new york. yoder,e.j and witezak ,m.w.(1975):"principles of pavement design",2nd edition ,john willey and sons inc.,new york. table (1) chemical properties of gypsum and anhydrite (al-mufty, 1997) h2oso3caotype 20.946.532.6gypsum 058.841.2anhydrite table, (2) results of geotechnical properties of the soil used properties value depth (0.70 to 1.3),m specific gravity 2.4 liquid limit,( l.l )% 38 plastic limit,( p.l )% 20 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٧٩ soil classification,(ashto ) a-2-6 (0) soil classification,(uscs) sc total soluble salts, (t.s.s) 68.73 total,( so3)% 31.24 ph 7.4 gypsum content,% 63 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 0 .0 10 .111 0 % f in er b y w ei gh t g rain size d iam eter in ,m m f igu re 1 g rain size d istrib u tion d iagram for soils al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٠ figure (2), procter compaction curves for samples. 14 14.5 15 15.5 16 16.5 17 17.5 18 18.5 19 0 5 10 15 20 water content,(% ) d ry d en si ty ,(k n /m 3) modified procter standard procter figure(3) effect of leaching periods on cbr under various surcharge loads with, (i=2) 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 leaching period ,day c b r % loads,311.5n loads,178n loads,44.5n al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨١ figure(4) effect of leaching periods on cbr under various surcharge loads with, (i=6) 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 leaching period ,day c b r % loads,311.5n loads,178n loads,44.5n al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٢ figure (5) effe ct of le aching pe riods on cbr unde r various s urcharge loads with, (i=10) 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 l e ach i n g pe ri od ,day c b r % loads,311.5n loads,178n loads,44.5n figure (6) leaching strain versus time relation with i=2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 10 20 30 40 50 60 70 leaching period,day st ra in loads,311.5n loads,178n loads,44.5n al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٣ figure (7) leaching strain versus time relation with i=6 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 10 20 30 40 50 60 70 leaching period,day st ra in loads,311.5n loads,178n loads,44.5n figure (8) leaching strain versus time relation with i=10 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 10 20 30 40 50 60 70 leaching period,day st ra in loads,311.5n loads,178n loads,44.5n al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٤ figure (9) relationship between cbr% and dry density after leaching 30 35 40 45 50 55 60 15 15.5 16 16.5 17 17.5 18 18.5 dry density,kn/m3 c b r ,% leaching,i=10 leaching,i=6 leaching,i=2 figure (10) water supply system to the water distributer two elevated cylindrical tank rubber tube rubber tube tab. water floating ball floating ball upper tank lower tank al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٥ figure (11) arrangement of the modified oedometer plate (1) parts of modified leaching mold inlet al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٦ plate (2) modified oedometer with cell under test plate (3) modified oedometers with cells under test al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 803 an active self-tuning suspenion system to improve driver comfort dr. salim y. kasim salim56y@yahoo.com mech. eng. department, college of eng., tikrit university abstract this paper presents the simulation of two dimension a half-vehicle self –tuning active suspension system to simultaneously improve vehicle ride comfort. a validated 4-dof of vehicle linear model was used to study the performance of passive suspension system and compared with the developed active suspension system. the governing equations of motion for the selftuning active suspension was derived and used to reduce the effect of disturbances to the dynamics performance of the vehicle, which appear when the vehicle excited by a semi-circular sinusoidal bump road of a (0.1 m) height. the performance of passive suspension and the self-tuning active suspension are demonstrated by simulations and specially the vertical acceleration and the vertical root mean square (rms) acceleration to observe the effect of the proposed system to the ride comfort. the active suspension system introduced in this work show good results for improving the ride comfort. keywords: self-tuning active suspension, ride comfort. نظام تعليق ذو تضبيط ذاتي فعال لتحسين راحة السائق د. سالم يحيى قاسم تكريت/ كلية الهندسة/ قسم الهندسة الميكانيكيةجامعة الخالصة: فعال نظاِم تعليقِ تحتوي على مركبةِ ِنْصف لموديل ثنائي البعد خطي ذو اربع درجات من الحرية لمحاكاَة في هذا البحث نموذج عمُل لِدراَسة أداِء نظاِم التعليِق السلبيِ خطي َكاَن ُيستَ استند البحث على نموذج بشكل آني. كباالر َتْضبيط ذاتِي لَتحسين راحِة ذو تأثير واستخدمت بتقليل التعليَق النشيَط لنظام المعادالت الَحاِكمة للحركِة تم اشتقاق بنظاِم التعليِق النشيِط المطوِر. للمقارنة هشكل نصف دائري لموجية جيبي بصدمة طريق على العربَة عندما تثار، الذي َيْظهُر مركبةأداِء ديناميكا العلى االضطرابات بالمحاكاِة وخصوصًا التعجيِل العموديِ تم عرضه. إّن أداَء التعليِق السلبِي وتعليِق الَتْضبيط الذاتِي النشيِط متر 0.1 بارتفاع al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 803 نظام التعليِق تظهران وقد وجد انه هناك نتائج كب .الراراحِة علىلُمالَحَظة تأثيِر النظاِم الُمقَتَرِح ومعدل مربع الجذر للتعجيل الراكب.نتائج جيدة لَتحسين راحِة قد اعطى البحثِ في هذا المقدم النشيِط nomenclature ms sprung mass mu un sprung mass. vertical acceleration of sprung mass. vertical velocity of sprung mass. vertical displacement of sprung mass main suspension coefficient of damping. main suspension stiffness. the centre of tyer (wheel) vertical displacement. the centre of tyer (wheel) vertical velocity. the sprung mass cg vertical acceleration. the centre of tyer (wheel) vertical acceleration. road profile vertical amplitude. ca self-tuning damper coefficient of damping. the force frequency. c.g the sprung mass center of gravity. introduction: ride quality and handling performance of road vehicles are very much affected by the design of the vehicle suspension systems. good ride quality requires high damping setting at low frequencies to stifle bounce, roll and pitch, and lower damping settings at higher frequencies to avoid ride harshness. unlike passive systems, which can only store or dissipate energy, active suspensions can continuously change the energy flow to or from the system when required, recently, the subject of active suspension design has been intensively reviewed by jean-gabriel roumy [1], m .frechin [2], and mario milanese and carlo novara [3], a simulation procedures by jean-gabriel roumy [4], and pakharuddin mohd samin, hishamuddin jamaluddin [5] . an optimization of active suspensions by applying methods of modern control theory has been reported by bassam a. [6]. the vehicle suspension provides a means of isolating the vehicle’s body from the road inputs. several aspects of vehicle dynamics put different demands on the various suspension components. occupant comfort requires the minimization of sprung mass accelerations, while lateral dynamic performance requires good road holding giving rise to a need for consistent normal forces at the tire al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 810 interface. this all has to work within suspension rattle space and tire deflection limitations. in a passive suspension each improvement comes at the expense of performance in another area [10].in this work, it is proposed to develop an analytical self-tuning active suspension to effectively reduce the vehicle body acceleration for ride comfort, dynamic tyers deflections and body attitude for ride handling and suspension deflections for the purpose of packaging by means of active suspensions governing equations of motion. the objectives include: (1) development of a half car model, which is adequate for understanding the effect of road disturbances on the ride and handling characteristics of the vehicle; (2) deriving the optimal governing equations of motions of a self -tuning active system (3) investigating the possibilities of performance improvements using the passive and active developed system for a simulation to see the vibration response of wheel center behavior and the c.g acceleration to study its effects on ride comfort. analytical formulation: 1. model of vehicle ride dynamics: the two dimensional 4-dof half vehicle model as shown in figure 1 is based on a passive fem vehicle model being validated by simulation results by salim y. kasim [7], so in this work the passive suspension is replaced with an self-tuning active suspension which is represented parallel damper to the passive one, vertical motion in the zdirection, pitch motions about the pitch pole. it also consist two unsprung masses which are free to bounce vertically with respect to the sprung mass. the vehicle model parameters data used for the simulation were taken from [9] as shown in table (1). 2. vehicle model governing equations: the equations governing the dynamic motion of the vehicle model equipped with self-tuning active and passive suspension systems can be expressed in the following state form: ) ( ) (1) ) ( ) (2) where: ): self-tuning damper force. and the amplitude of vibration for both sprung and un sprung masses can be written as follows: the vertical amplitude of vibration of the vehicle sprung mass is: (3) and the vertical amplitude of vibration of the un sprung mass is: (4) the displacements, velocity, and acceleration with respect to time can be obtained. 3. vehicle and bump road input: the input excitation to the vehicle model is assumed to be the apparent vertical roadway motion, caused by the vehicle’s forward speed along a road having a semi-circular sinusoidal profile of 0.1 meter amplitude and 0.6 meter length as shown in figure 8. the vehicle excitation model can be obtained in the shape of vertical elevation and horizontal distance as tabulated input. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 811 results and discussions: a new approach of an active suspension selftuning damper has been achieved, according to the results it clear that from the observation of the front and rear road wheels vertical displacement shown in figure (2), that the amplitude have been reduced to about the half . also in figure (4) it is clear that the in addition to a code contact between the road wheel and the terrain the vertical spring mass c.g's amplitude is reduced from which one can deduced the results shown in figure (3) with high response and low settling time. the root mean square (rms) acceleration is one of a ride comfort criteria which is shown in figure (5) for a smooth low values in active compared to that in the passive one. in the low speed of the vehicle in both case active and passive there are deference in the response can be observed the reason is that a good contact were exist between the road profile and the tyre, but the deferent is appear small when the speed is increased, except at some speeds mainly at 40 km/h which is seem to be the critical speed, these facts can be observed in figures (5) and (7). and in this case a sudden shock can be avoided when the speed of the vehicle has increased. the proposed system show a good time response if we checked the simulation time and the length of the road bump which is 0.6 meter and the critical time need from the system to reply is about two second in this case we need a high response system and it is clear from the results shown in figures (2 through 7) that the system has managed to do. and the reduction of the vertical acceleration is about 2 times. it means that the proposed system has achieved the objects conclusion: a selftuning suspension simulation system based on an additional damper added to the passive one in a 2-d half vehicle 4 dof model the new damper has the ability to modified itself according to the irregular road profile after it received a signal from the detector where it can be achieved on reading the input tabulated data before the first wheel reach it, and adjust itself to maintained a suitable damping help for overcome the non-uniformly road to make the ride comfort be better. the results have shown that the proposed system has achieved the aim. refrances: 1. jean-gabriel roumy, benoit boulet and dany dionne (active control of vibrations transmitted through a car suspension), int. j. vehicle autonomous systems, vol. 2, nos. 3/4, 2004. 2. m frechin1, s b arin˜o and j fontain (actiseat: active vehicle seat for acceleration compensation), imeche 2004 3. mario milanese and carlo novara (experimental modeling of vertical dynamics of vehicles with controlled suspension), 2004 sae international. 4. jean-gabriel roumy*, benoit boulet and dany dionne (active control of vibrations transmitted through a car suspension), 2004 inderscience enterprises ltd. 5. pakharuddin mohd samin, hishamuddin jamaluddin (semi-active suspension for ride improvement using stability augmentation system control algorithm), jurnal mekanikal december 2008, no. 26, 86 – 95 6. bassam a. albassam , ahmad a. fayed, and mohamed m. elmadany (optimal linear preview control of slowactive suspension systems) proceedings of the 7th saudi engineering conference (sec7) 7. salim y. kasim ' ride analysis for suspension system of off-road tracked vehicles' phd thesis 1990-1991 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 813 8. judi-chun chang (analysis of series type and parallel type active suspension systems), hsinchu, taiwan, november, 7, 2007 9.vehicle suspension modeling mece 4333 vehicle systems modeling and control the university of texas pan american august 7, 2006 10. d. geoff rideout ,and keith j. wakeham ( model complexity requirements in design of half car active suspension controllers) proc. asme dynamic systems and controls conference, arlington, va oct. 31-nov.2, 2011 figure(2) comparison of unsprung mass displacement vs time at 20 km/h figure (1) 2-d half car model with self -tuning suspension. tuning al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 818 fig (3) sprung mass c.g vertical acceleration vs time at 20 km/h fig( 4) front wheel , sprung mass c.g displacements , and road test bump profile vs time at low speed (active). fig (5) sprung mass c.g root mean square vs vehicle speeds fig (6) sprung mass c.g pitch angle vs time at 20 km/h al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 813 fig (7) sprung mass c.g maximum acceleration vs vehicle speeds. figure(8) the test bump road used in this study. microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 large displacement elastic-plastic analysis of laminated composite plates under in-plane compressive loads dr. husain m. husain professor in civil engineering, university of tekrit dr. nameer a. alwash professor in civil engineering, university of babylon dr.haider k. ammash lecturer. in civil engineering, university of al-qadisiya abstract a nonlinear finite element method is adopted for the large displacement elastic-plastic static analysis of anisotropic plates under in-plane compressive loads. the analysis is based on the twodimensional layered approach with classical and higher order shear deformation theory with five, seven, and nine degrees of freedom per node. nine-node lagrangian isoparametric quadrilateral elements are used for the discretization of the laminated plates. effects of orthotropy of individual layers, through-thickness shear deformation, fiber’s orientation angle, and fiber waviness on the large displacement elastic-plastic static analysis are considered. the plate is analyzed with a range of number of sequences (k) of sine wave fiber (1-12) and with a range of the amplitude of fiber path (∆) of sine wave fiber (0.0-0.5). the conclusion it is shown that the behavior of the laminated plate is very sensitive to the shape of fibers (straight or sine wave), also the behavior of the plate with sine wave fiber depends on the amplitude of the fiber and the number of sequences of the fiber, and so the capacity of the laminated plate with sine wave fiber and under in-plane compressive load in the direction of waviness is higher than the capacity of the plate with sine wave fiber and under inplane compressive load orthogonal to the direction of waviness by approximate value (42%). keyword: large displacement, elastic-plastic analysis, finite element method, composite plate, in-plane compressive loads. حمل ضغط في تأثيراللدن للصفائح غير متماثلة الخواص تحتالمرنةالكبير اإلزاحةليل حت المستوي حيدر آاظم عماش.د القادسيةجامعة/مدرس نمير عبد األمير علوش. د جامعة بابل/أستاذ مساعد حسينحسين محمد .د جامعة تكريت/أستاذ -:الخالصة اللدن االستاتيكي للصفائح غير متماثلة الخواص تحت المرن ةالكبير اإلزاحة تم تقديم طريقة العناصر المحددة الالخطية لتحليل واعتمدت ) two-dimensional layered approach( الطبقة ثنائي البعد الدراسة طريقة هتبنت هذ . حمل ضغط في المستوي مع ) classical and higher order shear deformation theory(نظرية التشوهات القصية الكالسيكية وذات المرتبة العليا . ةي ذي العقد التسع لتمثيل الصفائح الطبق )lagrangian ( الآرانجت حرية لكل عقدة، تم توظيف عنصراسبع وتسع درجوخمس، الكبيره اإلزاحة على تحليل األلياف تموج واأللياف زاوية تدوير الخواص للطبقات المنفردة و تعامدخذ بنظر االعتبار تأثير ُأ قدو من ارتفاع قمة االلياف جال، وم)12-1( من تسلسل االلياف المتموجة مجالتم تحليل الصفيحة مع . اللدن االستاتيكي-المرن al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 2 مستقيم او ( لشكل االلياف ة حساس جداً ي طبقرف الصفائح الُ تص ن من النتائج المستحصلة، يمكن مالحظة ا ). 0.5-0.0(المتموجة قابلية وآذلك ان ’عتمد على ارتفاع قمة االلياف وعدد تسلسل التموجات مف الصفائح ذات االلياف المتموجة تصّروأيضا ). متموج ة والمتموجة ي التحمل للصفائح الطبقبقة والمتموجة االلياف وتحت حمل ضغط في اتجاه التموج اآثر من قابلية ّطالتحمل للصفائح المُ .)%42(االلياف وتحت حمل ضغط عمودي على التموج بحوالي notations symbol description a, b plate dimensions in x and y-directions, respectively. [b] strain-nodal displacement matrix. d flexural rigidity = ( )23 112 vet − . ei modulus of elasticity in i-direction. ef modulus of elasticity of fiber. em modulus of elasticity of matrix. fi, fij strength tensors of the first and second order, respectively. {f} external load vector. f yield function. g shear modulus. hl-hl-1 distance from plate middle surface to the upper and lower surface of lth lamina. h plate thickness. [ ]ok constant linear elastic stiffness matrix [ ]lk initial or large displacement matrix [ ]σk initial stress stiffness matrix [ ]0tk tangent stiffness matrix. xyyx mmm ,, bending and twisting moments (per unit width) (on yz, xz, and both yz and xzsections). *** ,, xyyx mmm higher order bending and twisting moments (per unit width) (on yz, xz, and both yz and xz-sections). xyyx nnn ,, in-plane stress resultants (per unit width) (on yz, xz, and both yz and xz-sections). *** ,, xyyx nnn higher order in-plane stress resultants (per unit width) (on yz, xz, and both yz and xz-sections). px in-plane applied load in x-direction. qx, qy transverse shearing forces (per unit width) (on yz and xz-sections). wo amplitude of initial imperfection. x,y,z coordinates. o ijγ shear strain in ij-plane at middle surface. *o ijγ higher order shear strain in ij-plane at middle surface. { }ε strain vector. { }oε middle surface strain vector. iε normal strain in i-direction. o iε normal strain in i-direction at middle surface. *o iε higher order normal strain in i-direction at middle surface. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 3 ηξ , curvilinear coordinates system. θ fiber’s orientation angle. θx,θy rotations of transverse normals in the (xz) and (yz) planes. ** , yx θθ higher order rotations of transverse normals in the (xz) and (yz) planes. o iκ bending curvature in i-plane at middle surface. o ijκ bending curvature in ij-plane at middle surface. *o iκ higher order bending curvature in i-plane at middle surface. *o ijκ higher order bending curvature in ij-plane at middle surface. vi poisson’s ratio in i-direction. oσ yield stress of steel introduction the composite material is made of two or more macro-constituent's materials essentially soluble or mixable into each other, usually a reinforcing material supported in a compatible matrix, where the sum of properties of each constituent taken separately, are assembled in prescribed amounts to achieve specific physical and chemical properties [jones,1999](9). the reinforcement materials may form as continuous or discontinuous fibers, flakes, fillers or particles embedded in the matrix material. fibers in various forms (mat yarn, woven roving, and chopped strands) are inherently much stiffer and stronger than the same material in bulk form. the matrix material works as a binder material giving the composite a protection and supports its bulk form and stress transfer when the fiber is broken. typically, the matrix is of considerably lower density, stiffness and strength than those of the fibers. layered composite material plates are extensively used in the construction of aerospace, civil, marine, automotive and other high performance structures, and during the operation of this structure, it is subjected to static and dynamic loads, as shown in figure (1). therefore, there exists a need for investigating the response of layered (laminated) composite material plates subjected to such types of loading. the finite element method has been applied with great success to geometrical and material nonlinearities in continuum and structural problems. the geometric nonlinearity is modeled by well-known formulations, the total or updated lagrangian coordinates, while success in modeling the material nonlinearities depends on the validity of the constitutive models to be used. elseifi [1998](7) presented nonlinear finite element method for the post-buckling analysis of stiffened composite panels with geometric imperfections. a four node, six degrees of freedom per node, rectangular, conformal element was used. transverse shear effects were neglected since the width to thickness ratio of the panels under consideration is over 500. a maximum stress failure criterion was added to the finite element code to predict the panel post-buckling failure load. a new integration technique that mixes symbolic closed-form function manipulation and gaussian quadrature numerical integration had been introduced in order to reduce the required computation time for each analysis. his study did not take the effect of fiber orientation, number of fibers, and type of initial imperfection. shukla and nath [2000](15) presented a post-buckling analysis of shear deformable cross-ply laminated rectangular plate subjected to the combination of in-plane edge compressive mechanical loading and thermal loads due to a linearly varying temperature across the thickness. their formulation was based on the first order shear deformation theory and vonkarman type nonlinearity. they observed that their present method was quite efficient in obtaining the buckling and post-buckling response of a laminated composite plate under thermomechanical al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 4 loading. more recently, zou and qiao [2002](16) presented a higher order finite strip method for post-buckling behavior of imperfect composite plates subjected to progressive end shortening. the arbitrary nature of initial geometric imperfection induced during manufacturing was accounted for in the analysis. the nonlinear equilibrium equations were solved by newton-raphson method. that study showed that the post-buckling behavior of an imperfect composite plate depends not only on the material lay up, snap-to-thickness and anisotropy of the laminate, but also on the direction of induced out-of-plane imperfection. from the preceding review of literature, it is clear that there is no study which considers the nonlinear static analysis of isolated laminated plate under axial compression load by taking into account the effect of type of fiber (straight or wavy). there is also a little amount of literature that takes into account the higher order displacement model of nine degrees of freedom per node with different types of lamination. laminated plate theories a laminated plate is a series of laminas bonded together to act as an integral structural element. thus, a laminate is not a material but instead a structural element with essential features of both material properties and geometry. the stiffness and strength of such a composite material with structural configuration are obtained from the properties of the constituent laminas, and thus the macromechanical behavior of a laminate is the main topic of this section. the lamination so described can be considered as a single layer with "rule of mixtures" representation of the interaction between the multiple laminas in a plate or shell [jones, 1999](9). there are two categories of theories, equivalent single layer and three dimensional elasticity theories. in the first category, the material properties of the constituent layer are smeared to form a hypothetical single layer whose properties are equivalent to through thickness integrated sum of its constituents, and this category contains classical lamination theory, first order shear deformation theory, and higher order shear deformation theory. the higher order shear deformation theories are more efficient to represent the transverse shear deformation, through-thickness displacement and strains. the assumption of a higher order plate theory can also be used within the equivalent layer formulation [jones, 1999](9). the strain expressions derived from the displacement field were considered by [ali, 2004](2) with nine degrees of freedom per node as follows: ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )tyxwtzyxw tyxztyxvztyxztyxvtzyxv tyxztyxuztyxztyxutzyxu o yoyo xoxo ,,,,, ,,,,,,,,,,, ,,,,,,,,,,, ** ** = θ++θ+= θ++θ+= 32 32 (1) in which the parameters (u, v, w, θx, θy, * xθ , and * yθ ) are defined previously, * ou , and * ov are the corresponding higher order terms in taylor's series expression and they are also defined at the middle plane. the strain-displacement relations after differentiating equation (1) are: * * ** ** ** y o yzyyz x o xzxxz xy o xyxy o xyxy y o yy o yy x o xx o xx zz y w z v zz x w z u zzz x v y u zzz y v zzz x u ϕ+γ+ϕ= ∂ ∂ + ∂ ∂ =γ ϕ+γ+ϕ= ∂ ∂ + ∂ ∂ =γ κ+γ+κ+γ= ∂ ∂ + ∂ ∂ =γ κ+ε+κ+ε= ∂ ∂ =ε κ+ε+κ+ε= ∂ ∂ =ε 2 2 32 32 32 (2) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 5 where y w x w xyyx x v y u y v x u o yy o xx yx xy y y x x ooo xy oo y oo x ∂ ∂ += ∂ ∂ += ∂ ∂ + ∂ ∂ = ∂ ∂ = ∂ ∂ = ∂ ∂ + ∂ ∂ = ∂ ∂ = ∂ ∂ = θϕ θϕ θθ κ θ κ θ κ γεε ,, ,, * o *o yz * o *o xz * o * o*o xy * o*o y * o*o x v u x v y u , y v , x u 2 2 =γ =γ ∂ ∂ + ∂ ∂ =γ ∂ ∂ =ε ∂ ∂ =ε (3) also, all the strains above are defined in the middle-plane of the laminate. by substitution from equation (3) into the stress-strain relations given by the following equation: ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ = ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ yz xz xy y x yz xz xy y x qq qq qqq qqq qqq γ γ γ ε ε τ τ τ σ σ 4445 4555 662616 262212 161211 000 000 00 00 00 (4) after complete integration, the stress-resultant/strain relations of the laminate are as follows(4): ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ κ κ κ κ κ κ γ ε ε γ ε ε ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ = ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ * * * * * * * * * * * * xy y x xy y x o xy o y o x o xy o y o x xy y x xy y x xy y x xy y x hhhfffgggeee hhhfffgggeee hhhfffgggeee fffdddeeebbb fffdddeeebbb fffdddeeebbb gggeeefffddd gggeeefffddd gggeeefffddd eeebbbdddaaa eeebbbdddaaa eeebbbdddaaa m m m m m m n n n n n n 662616662616662616662616 262212262212262212262212 161211161211161211161211 662616662616662616662616 262212262212262212262212 161211161211161211161212 662616662616662616662616 262212262212262212262212 161211161211161211161211 662616662616662616662616 262212262212262212262212 161211161211161211161211 (5) and, ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ϕ ϕ γ γ ϕ ϕ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ = ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ * y * x *o yz *o xz y x * y * x y x y x ffeedd ffeedd eeddbb eeddbb ddbbaa ddbbaa q q s s q q 444544454445 455545554555 444544454445 455545554555 444544454445 455545554555 (6) all coefficients in a, b, d, e, f, g, and h groups are defined as follows: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 6 ∑ = −−= nl l llijij hhqa 1 1 )( i, j = 1, 2, 6 or i, j= 4, 5 (7 a) ( )∑ = −−= nl l llijij hhqb 1 2 1 221 )( i, j = 1, 2, 6 or i, j= 4, 5 (7 b) ( )∑ = −−= nl l llijij hhqd 1 3 1 331 )( i, j = 1, 2, 6 or i, j= 4, 5 (7 c) ( )∑ = −−= nl l llijij hhqe 1 4 1 441 )( i, j = 1, 2, 6 or i, j= 4, 5 (7 d) ( )∑ = −−= nl l llijij hhqf 1 5 1 551 )( i, j = 1, 2, 6 or i, j= 4, 5 (7 e) ( )∑ = −−= nl l llijij hhqg 1 6 1 661 )( i, j = 1, 2, 6 (7 f) ( )∑ = −−= nl l llijij hhqh 1 7 1 771 )( i, j = 1, 2, 6 (7 g) the present study explores the idea of tailoring the profile of reinforcing fibers to improve the buckling strength of composite plates. this study investigates the effect of waviness of fibers on the post buckling curves, as shown in figure (4), and this waviness is of the form: ( ) ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ π α= a xk xy sin (8) such that the angle of fiber orientation θ varies along the longitudinal x-axis as: ( ) ( )xkk a xk a k dx dy ππ∆=⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ππα ==θ cos.cos.tan (9) where a = plate length; k= number of half sine waves; and α= wave amplitude. two normalized variables, ∆=α/a and axx /= , are introduced. the main objective is to study the effect of fiber waviness, characterized by k and ∆, on the static and dynamic buckling behavior of composite laminates. the fiber can also be rotated in any direction with the x-axis, as shown in figure (4), by using the following expression: ( ) ( )β+β= sincos yxxn (10) where xn represent the x-coordinate for a rotated fiber, and β is the angle of the waviness fiber. the angle of fiber orientation in equation (9) is variable with x-coordinate and instead of the constant angle used for straight fibers. figure (5) shows the principal material directions aligned with the lamina axes by angle (β ). geometrical nonlinearity the components of the green-lagrangian strain vector are known in terms of local derivatives of the displacements for the plate element as [pica, et al., 1979](13): [ ] ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ε + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ε + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ ε ε + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ε = ⎪ ⎪ ⎪ ⎭ ⎪⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎩ ⎪⎪ ⎪ ⎨ ⎧ γ γ γ ε ε =ε 000 p i p l s o b o p o yz xz xy y x z (11) where the linear mid-plane strains are: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 7 [ ] ⎪ ⎪ ⎪ ⎭ ⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎩ ⎪ ⎪ ⎪ ⎨ ⎧ ∂ ∂ + ∂ ∂ ∂ ∂ ∂ ∂ =ε x v y u y v x u p o (12) equation (12) represents the in-plane strain. also: [ ] ⎪ ⎪ ⎪ ⎭ ⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎩ ⎪ ⎪ ⎪ ⎨ ⎧ ∂ θ∂ + ∂ θ∂ ∂ θ∂ ∂ θ∂ =ε xy y x yx y x b o (13) equation (13) represents the bending strain. also: [ ] ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ ϕ ϕ =ε y xs o (14) equation (14) represents the shear strain. moreover: [ ] ⎪ ⎪ ⎪ ⎪ ⎭ ⎪⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎪ ⎩ ⎪⎪ ⎪ ⎪ ⎨ ⎧ ∂ ∂ ∂ ∂ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ∂ ∂ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ∂ ∂ =ε y w x w y w x w p l 2 2 2 1 2 1 (15) equation (15) represents the nonlinear component of in-plane strain. finally: [ ] ⎪ ⎪ ⎪ ⎭ ⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎩ ⎪ ⎪ ⎪ ⎨ ⎧ ∂ ∂ ∂ ∂ + ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ =ε y w x w y w x w y w y w x w x w oo o o p i (16) equation (16) represents the initial strain due to initial deflection. the vector components of equation (11) represent the generalized strains. it can be noted that the vector ( pl p l o p ε+ε+ε ) reproduce the marguerre strain expression for plate. variational equation of equilibrium the variation of strain dε due to the virtual displacements du, generally dε is given as the sum of the variation of the linear and nonlinear generalized strains as: lo ddd ε+ε=ε (17) since oε is a linear function of displacement, [ ]dubd oo =ε (18) also, [ ]dubd ll =ε (19) thus, the total strain-nodal displacement matrix for total strains is: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 8 [ ] [ ] [ ]lo bbb += (20) in which [ ]ob is the same matrix as in the linear strain analysis and [ ]lb depends on the displacements. [ ] [ ] ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ =⎥ ⎦ ⎤ ⎢ ⎣ ⎡ = 00 0 0 0 bl lb o p o o b b b b b , (21) where [ ]lb can be found by taking the variation of the nonlinear strain components { }plε with respect to the displacements. this nonlinear strain components of equation (11) can be written in a more convenient form as: [ ] [ ]{ }θ= ⎪ ⎪ ⎭ ⎪⎪ ⎬ ⎫ ⎪ ⎪ ⎩ ⎪⎪ ⎨ ⎧ ∂ ∂ ∂ ∂ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ = ⎪ ⎪ ⎪ ⎪ ⎭ ⎪⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎪ ⎩ ⎪⎪ ⎪ ⎪ ⎨ ⎧ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ∂ ∂ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ∂ ∂ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ∂ ∂ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ∂ ∂ =ε θa y w x w x w y w y w x w y w x w y w x w p l 2 1 0 0 2 1 2 1 2 1 2 2 (22) where the displacement gradients with respect to the lateral displacements (w) are: { } ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ∂ ∂ =θ y w x w (23) then, the variation of the nonlinear component of the in-plane strain is obtained from equation (22) in terms of the virtual gradients dθ as: θ=ε θ dad p l (24) where ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ =θ x w y w y w x w a 0 0 (25) in which, aθ represents the gradients of total displacements and, ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ∂ ∂ =θ y w x w dd (26) represents the gradients of incremental displacements. the displacement gradients (θ) of equation (23) may now be written in terms of the nodal displacements (u) and cartesian derivatives of the shape functions as: { } [ ]{ }ug=θ (27) where [ ] [ ]ngggg .......21= (28) and, al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 9 ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ∂ ∂ = 0000 0000 y n x n g i i i (29) the above equation represents the gradient for five degrees of freedom per node. taking the variation of equation (22) as follows: { } [ ]{ } [ ] { } [ ] { } [ ][ ] { }udgadadaadd pl θθθθ =θ=θ+θ=ε 2 1 2 1 (30) hence immediately, by definition [ ] [ ][ ]gab obl θ= (31) in order to incorporate the imperfections in the formulation, the strain due to imperfections as given in equation (11), thus can be written the imperfection strain components as follows: { } [ ]{ }θ= ⎪ ⎪ ⎭ ⎪⎪ ⎬ ⎫ ⎪ ⎪ ⎩ ⎪⎪ ⎨ ⎧ ∂ ∂ ∂ ∂ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ =ε 12 1 22 20 02 2 1 a y w x w x w y w y w x w oo o o i p (32) following the same analysis as for the nonlinear strains, the combination of the effects of the two strains into one [ ]blb is defined as: [ ] [ ][ ]gab bl 2= (33) where [ ] [ ] [ ]12 aaa += θ [ ] ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ∂ ∂ + ∂ ∂ ∂ ∂ + ∂ ∂ ∂ ∂ + ∂ ∂ ∂ ∂ + ∂ ∂ = x w x w y w y w y w y w x w x w a oo o o 22 20 02 2 (34) in the present study, the imperfection is assumed to be of sinusoidal function over the plate as: ( ) ⎟⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ π ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ π = yx oo l yn l xn wyxw sinsin, (35) where lx, and ly are the dimensions of the plate in the x, and y-direction, respectively. wo is the maximum value of the initial imperfection at the plate center. the variation in the potential energy of deformation for a plate element with large deflection can be written as: [ ] dvbdu t v σ= ∫ (36) substituting equations (36) can give the equilibrium equations written as: ( ) [ ] 0=−σ=ψ ∫ dwdvbu v t (37) where ψ represents the sum of external and internal generalized forces. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 10 clearly, the solution of equation (37) will have to be approached iteratively. in order to use an incremental solution procedure, the relation between du and dψ must be found. thus, taking appropriate variation of equation (37) with respect to du: [ ] [ ] dv du d bdv du bd du d t v t v σ σ ∫∫ += ψ (38) where the variation of the external load with respect to displacements is equal to zero, and thus equation (38) can be written at another form: [ ] [ ]kdv du bd du d t v l += ∫ σ ψ (39) where [ ] [ ] [ ][ ] [ ] [ ]lo t a kkdabdbk +== ∫ (40) the first term of equation (39) can be written as: [ ] [ ]σσ kdvdu bd t v l =∫ (41) where [ ]σk is a symmetric matrix dependent on the stress level. this matrix is known as initial stress matrix or geometric matrix. thus, [ ] [ ] [ ]( ) [ ] dukdukkkd tlo =++=ψ σ (42) with [ ]tk being the total, or tangent stiffness matrix. tangent stiffness matrix the tangent stiffness matrix can be written as: [ ] [ ] [ ] [ ]σ++= kkkk lot (43) where [ ]ok is the constant linear elastic stiffness matrix and can be written as: [ ] [ ] [ ][ ]dabdbk o t a oo ∫= (44) [ ]lk is the initial or large displacement matrix which is quadratically dependent upon displacement u, and can be written as: [ ] [ ] [ ][ ] [ ] [ ][ ] [ ] [ ][ ]dabdbdabdbdabdbk a o a t ll a t ll t ol ∫ ∫∫ ++= (45) finally [ ]σk is the initial stress stiffness matrix which has to be found by using the definition of equation (41). by taking the variation of equation (20) then: [ ] [ ] ⎥⎦ ⎤ ⎢ ⎣ ⎡ = 0 00 tb l t l bd bd (46) this on substitution into equations (41) and (34) gives: [ ] [ ] [ ]∫ ⎪ ⎪ ⎪ ⎪ ⎭ ⎪⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎪ ⎩ ⎪⎪ ⎪ ⎪ ⎨ ⎧ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ =σ a xy y x xy y x tt m m m n n n adg k 0 00 (47) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 11 however, using the mathematical properties of the matrix [a], this matrix can be written as: [ ] [ ]dag nn nn n n n ad yxy xyx xy y x t ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ = ⎪ ⎭ ⎪ ⎬ ⎫ ⎪ ⎩ ⎪ ⎨ ⎧ (48) and finally one can obtain [ ] [ ]⎥⎦ ⎤ ⎢ ⎣ ⎡ = σ σ bk k 0 00 (49) thus, [ ] [ ] [ ]dag nn nn gk a yxy xyxt ∫ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ =σ (50) failure criteria for laminated plate structure the stresses in an individual lamina are fundamental to control the failure initiation and progression in the laminate. the strength of each individual lamina is assessed separately by considering the stresses acting on it along the material axes. the initial failure of a lamina is governed by exceeding the maximum limit prescribed by a failure criterion. the determination of failure load is very essential in understanding the failure process as well as the reliability and safety of structures. the ultimate load that makes the plate fail is calculated based on tsai-wu criterion for general composite materials and on hashin criterion for fiber composite materials as follows [jones, 1999](9): 611 ,......,,; ==σσ+σ jiff jiijii (51) where fi and fij are strength tensors of the second and fourth order respectively and the usual contracted tensor notation is used except that 235134 τστσ == , ,and 126 τσ = . equation (51) is obviously very complicated thus it will restrict the above attention to the reduction of above equation for an orthotropic lamina under plane stress conditions: 12666 2 555 2 44432233113 2112 2 333 2 222 2 111332211 =σ+σ+σ+σσ+σσ+ σσ+σ+σ++σ+σ+σ+σ fffff fffffff (52) the terms that are linear in the stresses are useful in representing different strengths in tension and in compression. the terms that are quadratic in the stresses are the more or less usual terms to represent an ellipsoid in stress space, where 03 =f indicates that to the shear strength of a material in compression and in tension is similar, and 03 =σ in z-direction. also, the shear strength of a material is equal in three dimensions and equal to s. thus, the terms of fi is: 50 23 50 13 50 12 266255244 332211 321 1 2 1 1 2 11 2 1 111 111 111111 . .. ... ... , .. ,, . , . , . ,, ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛− = ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛− =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛− = ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ =⎟ ⎠ ⎞ ⎜ ⎝ ⎛ =⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ −=⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ −=⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ −= tcct tcctctct ctctct ctctct zzyy f zzxx f yyxx f t f s f r f zz f yy f xx f zz f yy f xx f (53) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 12 where, =tc xx , the axial or longitudinal strength in compression and tension. =tc yy , the transverse strength in compression and tension. =tc zz , the transverse strength in compression and tension. =str ,, shear strength of the material. equation (52) becomes as: 12666 2 555 2 4442112 2 222 2 1112211 =σ+σ+σ+σσ+σ++σ+σ+σ ffffffff (54) equation (54) is suitable for the elastic-plastic analysis of anisotropic materials. for matrix cracking failure, two different failure criteria are used depending on whether the transverse normal stress, 22σ , is in tension or in compression. the failure index, 2 me , is defined in terms of transverse tensile strength, yt , transverse compressive strength, yc, and in-plane shear strength, r, and is expressed as: 2 12 2 22 2 222 2 1 2 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ +⎟ ⎠ ⎞ ⎜ ⎝ ⎛ + ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ −⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = rrr y y e c c m τσσ for 022 <σ (55) and, 2 12 2 222 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ +⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = ry e t m τσ for 022 >σ (56) where (em) is the failure index for matrix cracking. matrix cracking is assumed to occur when the failure index (em) exceeds unity. fiber-matrix shear failure is assumed to be dependent on a combination of axial stress, 11σ , and shear stress,τ12, and is expressed as follows: 2 12 2 112 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ +⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = rx e t s τσ for 011 >σ and 2 12 2 11 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ <⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ rx t τσ (57) and, 2 12 2 112 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ +⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = rx e c s τσ for 011 <σ and 2 12 2 11 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ <⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ rx t τσ (58) where (es) is the failure index for fiber-matrix shearing, xt is the tensile strength along the fiber direction and xc is the compressive strength along the fiber direction. equations (57) and (58) predict that when the failure (es) exceeds unity, fiber-matrix shearing dominated failure occurs. fiber breakage failure occurs in tension due to the combination of axial stress and shear stress while the failure in compression is governed by buckling as expressed in terms of only axial stress. the criterion for breakage failure is expressed as follows: 2 12 2 112 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ +⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = rx e t f τσ for 011 >σ (59) and, 22 112 ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = c f x e σ for 011 <σ (60) where (es) is the failure index for fiber breakage. the fiber breakage failure occurs when (es) exceeds unity. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 13 applications and discussions in order to verify the reliability of the adopted numerical method, some case studies reported by other researchers are utilized. the study of the composite plate will be introduced. comparison with experimental investigation of composite plate the post-buckling and failure characteristics of flat, rectangular graphite-epoxy panels with and without holes that are loaded in axial compression have been examined in an experimental study by starnes and rouse [1981] and in a theoretical study by elseifi [1998](7). the panels were fabricated from commercially available unidirectional thornel 300 graphite-fiber tapes preimpregnated with 450 k cure narmco 5208 thermosetting epoxy resin. typical lamina properties for this graphite-epoxy system are 131.0 gpa for the longitudinal young’s modulus, 13.0 gpa for the transverse young’s modulus, 6.4 gpa for the in-plane shear modulus, 0.38 for the major poisson’s ratio (v12 ), and 0.14 mm for the lamina thickness. the loaded ends of the panel were clamped by fixtures during testing, and the unloaded edges were simply supported by knife-edge restrains to prevent the panels from buckling. in the present study, the plate is analyzed by using nine-node isoparametric lagrangian finite elements with nine degrees of freedom per node. the panel is 0.508 m long, 0.178 m wide, and 24-ply orthotropic laminate with [(45o/0o /-45o)2, (45o /0o /-45o)2, (45o /0o /90o)4] stacking sequence. the modeling approach of the quarter plate was based on using two elements in the short direction, and three elements in the long direction. the finite element mesh used is shown in figure (7). in order to efficiently proceed beyond the critical buckling point in the post-buckling analysis of the panel, an initial geometric imperfection in the same shape as the first buckling mode was assumed. the amplitude of this initial imperfection is (1%) of the total laminate thickness. figure (8) shows the out-of-plane deflection (w) near a point of maximum deflection (node i ) normalized by the panel thickness h as a function of the normalized load. from this figure, it can be noticed that good agreement exists with the experimental results with a difference not more than (6%). on the other hand, the present results are closer to the experimental investigation. comparison with theoretical investigation of composite plate a square cross-ply laminated plate with simply supported edges and initial imperfection was analyzed by zou and qiao [2002](16). lateral in-plane expansion is allowed at the loaded ends and the unloaded edges can be moved in the plane but remain straight. the layer material and geometry properties are presented in figure (9). the slenderness ratio is set as (b/h=20), and it represents a moderately thick laminate. the laminated plate contains eight equal-thickness layers in [0o/90o]4 layup. the initial imperfection (wo/h) is given by (0.0 and 0.1) by which the shape is considered to be a sinusoidal curve. zou and qiao used higher order finite strip method and solved the nonlinear equations by newton-raphson method. in the present study, a quarter of the laminate is modeled with (2×2) mesh of nine-node isoparametric lagrangian element with nine degrees of freedom per node. numerical results and response comparisons with zou and qiao [2002](16) are shown in figures (10) and (11) for axial load versus total deflection and axial load versus end shortening strain (ε). the present results are really close to those of zou and qiao [2002](16) with a difference of not more than (15%). parametric study a parametric study is performed to assess the influence of several important parameters on the elastic-plastic large displacement analysis of a composite laminated plate subjected to in-plane compressive load. the selected parametric studies are summarized as follows: 1. the effect of through-thickness shear deformation. 2. the effect of fiber’s orientation angle. 3. the effect of degree of orthotropy of individual layers. 4. the effect of fiber waviness. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 14 each one of the above parameters was studied individually by analyzing a type of laminated composite plate. in all cases, a nine-node element was used and also one quadrant of the plate was analyzed due to symmetry and (2×2) mesh is used in the cross-ply and straight fiber plates while for angle-ply and sine wave fiber plates, were analyzed by considering the full plates with (4×4) element mesh. lateral in-plane expansion is allowed at the loaded ends and the unloaded edges can be moved in the in-plane direction but remain straight. the initial imperfection shape is considered to be a sinusoidal curve. the following geometry and layer material properties of high graphite epoxy are used in the analysis: (e1=172.5 gpa; e2=7.08 gpa; g12=g13=3.45 gpa, g23=1.38 gpa; ef=341.42 gpa; em=3.58 gpa; vf=0.5; vm=0.5; v12=v13=v23=0.25, xt=xc=1450 mpa, yt=36 mpa, yc=230 mpa, s=62 mpa)[ parhi, et al., 2001](83). the geometry properties are (a=1.0 m, a/b=1). 1. effect of through-thickness shear deformation to show the effect of transverse shear deformation on the large displacement elastic-plastic analysis of laminated composite plate under in-plane compressive load, a simply supported plate with a range of slenderness ratio (b/h) from (20) to (120), with symmetric cross-ply and antisymmetric cross-ply arrangement and with six layers was analyzed. the initial imperfection is (wo/h= 0.1) by which the shape is considered to be a sinusoidal curve. figures (12) and (13) present the load-deflection curves of the symmetric cross-ply, and the antisymmetric cross-ply laminated composite plate under in-plane loading and with slenderness ratio (b/h=20) by taking the effects of transverse shear deformation through the degrees of freedom per node of the element. figures (14) and (15) show the effect of shear deformation of symmetric cross-ply, and antisymmetric cross-ply laminated composite plate under in-plane loading with range of slenderness ratio(b/h) (20-120). 2. effect of fiber’s orientation angle to study the effect of fiber’s orientation angle on the large displacement elastic-plastic analysis of laminated composite plates under in-plane compressive load, a square simply supported laminated plate with two layers was analyzed. the initial imperfection is neglected in the present study. figure (16) shows the effect of fiber’s orientation on the nonlinear analysis of composite laminated plate under in-plane compressive load. from this figure, it could be noticed that the ultimate strength of the plate with (0o/90o) gives ultimate load (651.2 kn/m). this orientation’s fiber means that it is the optimum for a plate under in-plane compressive load. 3. effects of fiber waviness to show the effect of fiber waviness on the large displacement elastic-plastic analysis of laminated composite plate, a square simply supported plate, with six layers was considered. the shape of fiber was considered to follow a sinusoidal curve. the effects of this type are (number of sequence (k), amplitude of wave (∆), and fiber’s orientation. the initial imperfection (wo/h= 0.1) by which the shape is considered to be sinusoidal curve. the value of amplitude of sine wave fiber is varying (∆=0.05-0.5) and the number of sequences of the sine wave fiber (k) was considered changeable in the range of (1-12). figures (17) and (18) present the load-deflection curves of laminated with symmetric crossply composite plate under in-plane compressive load and with sine wave fibers with a range of amplitude (0.05-0.5). figures (19)-(22) present the ultimate strength-fiber path amplitude (∆) curves for the laminated, with symmetric cross-ply, and antisymmetric cross-ply composite plates under in-plane compressive load and with a range of number of sequences (k) (1-12), respectively. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 15 conclusions a nonlinear finite element method is adopted for the large displacement elastic-plastic static analysis of anisotropic plates under in-plane compressive load. many of effects were considered in the present study such as the effect of orthotropy of individual layers, through-thickness shear deformation, fiber’s orientation angle, and fiber waviness on the large displacement elastic-plastic static analysis. the following conclusions are drawn with regard to the results obtained for the anisotropic plates under in-plane static loading as follows, 1) the capacity of a laminated plate with sine wave fiber under in-plane compressive load in the direction of waviness is more than the capacity of the plate under in-plane compressive load orthogonal to the direction of waviness by (42%) for a plate with sine wave fiber (k=12, ∆=0.4). 2) the ultimate strength of a cross-ply laminated plate is greater than the ultimate strength of an angle-ply laminated plate with the same laminas. 3) the ultimate strength of a symmetric cross-ply laminated plate is greater than the ultimate strength of an antisymmetric cross-ply laminated plate with the same laminas. 4) a symmetric cross-ply laminated plate with sine wave fiber (k=12, ∆=0.4) gives in-plane loading (610 kn/m) and this represents the peak capacity and this case is the best. references 1. abid-ali, a. k., “stress analysis of laminated fiber reinforced composite cylinder”, m.sc. thesis, university of babylon, hilla, iraq, 2000. 2. ali, n. h., “finite element dynamic analysis of laminated composite plates including damping effect”, m.sc. thesis, university of babylon, hilla, iraq, 2004. 3. amash, h. k., “post-buckling and post-yielding analysis of imperfect thin plate by finite difference method”, m.sc. thesis, university of babylon, hilla, iraq, 2003. 4. amash, h. k., “nonlinear static and dynamic analysis of laminated plates under in-plane forces”, ph.d. thesis, university of babylon, hilla, iraq, 2008. 5. chia, c.y., “nonlinear analysis of plates”, mcgraw-hill international book company, 1980. 6. cook, r.d., “finite element modeling for stress analysis”, john wiley & sons, inc., 1995. 7. elseifi, m., “a new scheme for the optimum design of stiffened composite panels with geometric imperfections”, ph.d. thesis, virginia polytechnic institute, u.s.a., 1998. 8. hashin, z. “failure criteria for unidirectional fiber composites”, asme, j. appl. mech., vol.47, 1980, pp.329-334. 9. jones, r.m., “mechanics of composite materials”, second edition, taylor and francis inc., u.s.a., 1999. 10. kaw, a., “mechanics of composite materials”, second edition, taylor and francis group, llc, 2006. 11. kommineni, j. r., and kant, t. “geometrically non-linear transient co finite element analysis of composite and sandwich plates with a refined theory.” struct. eng. and mech., vol.1, no.1, 1993, pp87-102. 12. pandey, m. d., “effect of fiber waviness on buckling strength of composite plates.” asce, j. eng. mech., vol.125, no.10, 1999, pp.1173-1179. 13. pica, a., wood, r.d., and hinton, e. “finite element analysis of geometrically nonlinear plate behavior using a mindlin formulation.” comp. & struct., vol.11, 1979, pp.203-215. 14. pica, a., wood, r.d “post-buckling behavior of plates and shells using a mindlin shallow shell formulation.” comp. & struct., vol.12, 1980, pp.759-768. 15. shukla, k.k., and nath, y., “thermomechanical post-buckling of cross-ply laminated rectangular plates”, asce, j. eng. mech., vol.128, no.1, 2002, pp.93-101. 16. zou, g., and qiao, p., “higher order finite strip method for post-buckling analysis of imperfect composite plates" j. eng. mech., vol.128, no.9, sep., 2002, pp.1008-1015. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 16 max. deflection ((w+wo)/h) present study theoretical results(31) experimental results(*) load (px/pcr) 0.010 0.010 0.010 0.00 0.013 0.020 0.021 0.10 0.017 0.030 0.042 0.30 0.035 0.060 0.063 0.60 0.064 0.110 0.125 0.75 0.210 0.280 0.310 0.90 0.770 0.645 0.850 1.10 1.122 1.021 1.176 1.28 1.495 1.380 1.580 1.50 1.645 1.500 1.720 1.60 1.930 1.720 2.020 1.80 2.068 1.810 2.166 1.90 2.203 1.900 2.333 2.00 * : given by starnes and rouse [1981] as mentioned in elseifi [1998](7). figure (1): use of composites in the space shuttle [kaw,2006](10) table (1): comparison of results with experimental and theoretical studies of composite laminated plate under in-plane compressive load in x-direction, (a/b=2.854, wo/h=0.1) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 17 figure (2): laminated plate with several lamina orientations[jones, 1999](9) laminas laminate response? conditions? h2 h1 h0 hn-1 hn-2 hn-3 hn h middle surface n layer number 1 2 figure (3): geometry of an nl-layered laminate [jones,1999](9) fiber (4): (a) lamina with variable fiber orientation; (b) geometry of sinusoidal fiber path [pandey,1999](12) lamina fibers y x b a α k=2 sinusoidal fiber path. (a) (b) figure (5): laminate plate with sine wave fibers aligned with x-axis β=0 β figure (6): idealizated stress-strain relationship of uniaxial loading behavior for orthrotropic plate[jones, 1999](9) ultimate point uε ε fσ σ al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 18 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 experiment by starnes elseifi present study (30) in -p la ne lo ad (p x/ p cr ) deflection ratio ((w+wo)/h) figure (8): post-buckling curve for a rectangular thin composite laminated plate under in-plane compressive load in xdirection px * (31) figure (7): finite element mesh and boundary condition for the quarter of the composite plate under in-plane compressive load in x-direction x u=0 v=0 θx=0 θy≠0 u=0 v=0 θx=0 θy≠0 u≠0;v=0 θy=0;θx=0 u=0;v=0 θx=0;θy=0 y 89 mm 25 4 m m i px px figure (9): details of a square laminated composite plate under in-plane compressive load and material properties a=200 (mm) b=200 (mm) h=10 mm e1/e2=20 g12/e2=g13/e2=0.6 g23/e2=0.5 e2=10 gpa v12=v13=v23=0.25 px x y figure (10): load-deflection curve of antisymmetric cross-ply imperfect rectangular thick composite laminated plate under compressive load,(b/h=20, a/b=1) end shortening strain ( ) figure (11): load-end shortening strain curve of antisymmetric cross-ply imperfect rectangular thick composite laminated plate under compressive load,(b/h=20, a/b=1) px 0.00 0.25 0.50 0.75 1.00 1.25 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 zou and qiao present study (124) in -p la ne lo ad (k n /m ) deflection ratio ((w+wo)/h) px 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 zou and qiao present study (124) in -p la ne lo ad (k n /m ) (16) (16) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 19 pxpx figure (12): load-deflection curve of symmetric cross-ply imperfect square composite laminated plate under in-plane compressive load with (b/h=20;a/b=1;wo /h=0.1) figure (13): load-deflection curve of antisymmetric cross-ply imperfect square composite laminated plate under in-plane compressive load with (b/h=20;a/b=1; wo /h=0.1) deflection ratio ((w+wo)/h) deflection ratio ((w+wo)/h) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 2500 5000 7500 10000 12500 15000 17500 antisymmetric cross-ply 5 dof (no shear effect) 7 dof (first order shear effect) 9 dof (higher order shear effect) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 2500 5000 7500 10000 12500 15000 17500 20000 symmetric cross-ply 5 dof (no shear effect) 7 dof (first order shear effect) 9 dof (higher order shear order) in -p la ne lo ad (k n /m ) in -p la ne lo ad (k n /m ) 5 dof (first order shear effect) 7 dof (higher order shear effect) 9 dof (higher order shear effect) 5 dof (first order shear effect) 7 dof (higher order shear effect) 9 dof (higher order shear effect) deflection ratio ((w+wo)/h) figure (16): effect of orientation’s fiber on the large displacement elastic-plastic analysis of composite laminated plate under in-plane compressive load (b/h=100; wo /h=0.0;a/b=1) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 orientation of layers 0/90 30/-30 45/-45 60/-60 75/-75 px in -p la ne lo ad (k n /m ) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 20 slenderness ratio ((b/h) figure (14): effect of number of degrees of freedom on the large elastic-plastic analysis of symmetric cross-ply composite laminated plate under in-plane compressive load with a range of slenderness ratio (b/h) slenderness ratio ((b/h) figure (15): effect of number of degrees of freedom on the large elastic-plastic analysis of antisymmetric cross-ply composite laminated plate under in-plane compressive load with a range of slenderness ratio (b/h) u lt im at e lo ad (k n /m ) u lt im at e lo ad (k n /m ) 20 40 60 80 100 120 0 2500 5000 7500 10000 12500 15000 17500 20000 20 40 60 80 100 120 0 2500 5000 7500 10000 12500 15000 17500 5 dof (no shear effect) 7 dof (first order shear effect) 9 dof (higher order shear effect) 5 dof (first order shear effect) 7 dof (higher order shear effect) 9 dof (higher order shear effect) 5 dof (first order shear effect) 7 dof (higher order shear effect) 9 dof (higher order shear effect) figure (17): load-deflection curve of simply supported square laminated composite plate with sine wave fiber with a range of fiber amplitude (0.05-0.50) and under in-plane compressive load, (wo/h =0.1;b/h=100;a/b=1.0;k=4) deflection ratio ((w+wo)/h) px 0 1 2 3 0 50 100 150 200 250 300 350 400 450 500 550 600 symmetric cross-ply 0/90/0/0/90/0 k=4, d=0.05 k=4, d=0.10 k=4, d=0.20 k=4, d=0.30 k=4, d=0.40 k=4, d=0.50 in -p la ne lo ad (k n /m ) k=4, ∆=0.20 k=4, ∆=0.30 k=4, ∆=0.40 symmetric cross-ply 0/90/0/0/90/0 k=4, ∆=0.50 k=4, ∆=0.05 k=4, ∆=0.10 laminated plate (0)6 k=4, ∆=0.05 k=4, ∆=0.10 k=4, ∆=0.20 k=4, ∆=0.30 k=4, ∆=0.40 k=4, ∆=0.50 figure (18): load-deflection curve of simply supported square symmetric cross-ply composite plate with sine wave fiber with a range of fiber amplitude (0.05-0.50) and under in-plane compressive load, (wo/h =0.1;b/h=100;a/b=1.0;k=4) deflection ratio ((w+wo)/h) px 0 1 2 3 4 5 0 100 200 300 400 500 600 laminated plate k=4,d=0.05 k=4,d=0.10 k=4,d=0.20 k=4,d=0.30 k=4,d=0.40 k=4,d=0.50 in -p la ne lo ad (k n /m ) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 21 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 250 300 350 400 450 500 550 laminated plate k=1 k=2 k=4 k=8 k=12 fiber path amplitude (∆) figure (19): ultimate load-fiber path amplitude curve of simply supported square laminated composite plate under in-plane compressive load in x-direction and with a range of number of sequences (1-12),(wo/h= 0.1, b/h=100, a/b=1.0) k=1 k=2 k=4 k=8 k=12 laminated plate (0)6 u lt im at e lo ad (k n /m ) px fiber path amplitude (∆) u lt im at e lo ad (k n /m ) figure (20): ultimate load-fiber path amplitude curve of simply supported square laminated composite plate under in-plane compressive load in y-direction and with a range of number of sequences (1-12),(wo/h=0.1, b/h=100, a/b=1.0) py 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 300 350 400 450 500 550 600 650 symmetric cross-ply k=1 k=2 k=4 k=8 k=12 laminated plate (0)6 k=1 k=2 k=4 k=8 k=12 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 250 300 350 400 450 500 550 600 650 laminated plate k=1 k=2 k=4 k=8 k=12 u lt im at e lo ad (k n /m ) fiber path amplitude (∆) figure (21): ultimate load-fiber path amplitude curve of simply supported square symmetric cross-ply composite plate under in-plane compressive load and with a range of number of sequences (1-12),(wo/h= 0.1, b/h=100, a/b=1.0) k=1 k=2 k=4 k=8 k=12 symmetric cross-ply 0/90/0/0/90/0 px fiber path amplitude (∆) u lt im at e lo ad (k n /m ) figure (22): ultimate load-fiber path amplitude curve of simply supported square antisymmetric cross-ply composite plate under in-plane compressive load and with a range of number of sequences (1-12),(wo/h= 0.1, b/h=100, a/b=1.0) px 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 300 350 400 450 500 550 600 650 antisymmetric cross-ply k=1 k=2 k=4 k=8 k=12 k=1 k=2 k=4 k=8 k=12 antisymmetric cross-ply 0/90/0/90/0/90 microsoft word 2.doc ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٥ معامل األداء ومعدل كتلة السناج املنبعث من حمرك ديزل يسار كاظم األنصاري مدرس مساعد قسم امليكانيك, كلية اهلندسة, جامعة الكوفة : اخلالصة سناج المنبعث من عادم محركات الديزل الى الجو الخارجي يعتبر أحد الملوثات الهواء الخطرة ألنه يحمل على سـطح جـسيماته ال لذا جـاء . مركبات هايدروكاربونية ذات تأثير سرطاني وبسبب صغر قطر هذه الجسيمات فانها بسهولة تستنشق وتدخل الى الرئتين تم اسـتخدام . المنبعث وسبل معالجته وتأثيره على معالم األداء لمحرك ديزل رباعي األشواط هذا البحث ليدرس معدل كتلة السناج بحيث تم اصطياد السناج بواسطة الـصوف , الطريقة المباشرة بقياس معدل كتلة السناج المنبعث والمعتمدة على ثقل السناج المتكون معدل كتلة السناج المنبعث والقـدرة المكبحيـة . المتأخرة من العادم الزجاجي الذي يعمل كفلتر داخل انبوبة تجميع توضع بالمراحل معدل كتلة السناج مع تغير الحمل تم مقارنتها بما هو مسموح به في ضـوء مقـاييس ). g/kw hr(للمحرك تم التعبير عنها بوحدات , )%95(في األحمال العالية التي تصل الـى وجد ). u. s. environmental protection agency, epa(وكالة حماية البيئة األمريكية كذلك زيـادة كتلـة ) tier1(زيادة في معدل كتلت السناج المتكون تتجاوز القيم المسموح بها لوكالة حماية البيئة في الطبقة االولى النتائج بينـت أن , يباتقر) 600co(السناج يحترق عادة بدرجة حرارة . السناج كانت سببا في النقصان الشديد لقدرة وكفاءة المحرك كتلة السناج المنبعث تكون كبيرة في االحمال العالية بحيث يمكن معالجتها رفع درجة حرارة العادم وإيصالها إلى درجة حرارة اكبر وجد ان كتلة السناج المنبعث لم , التي يصاحبها ارتفاع درجة حرارة العادم ) %70-%20(أما عند األحمال المتوسطة ). 600co(من ).tier2(والطبقة الثانية ) tier1(تتجاوز القيم المسموح بها في الطبقة االولى . وكالة محاية البيئة االمريكية, تلوث اهلواء, حمرك ديزل, الطريقة الوزنية, السناج: الكلمات الرئيسية parameters and the rate of soot emitted from diesel engine yassar k. alansari kufa university college of engineering, :abstract the soot (solid carbon particles) emitted from diesel engines into atmosphere is to consider one of dangerous pollutant because it is easy inhaled deep into the lungs and some polycyclic aromatic hydrocarbons known for their cancer properties are associated with it. the direct gravimetric method is used to measure the soot mass rate. the soot particles through the exhaust pipe are trapped using pyrex-glass collecting piece with glass wool filter. the rate of soot mass emitted and brake power are ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٦ expressed in (g/kw hr) unit. the variation of soot mass with engine load is compared with u. s. environmental protection agency (epa) standards. it is found as the engine load is increased, the rate of soot mass increases and exceeds the (epa) standards in the first tier. the high rate of soot mass causes strong decrease in the brake power and thermal efficiency. the soot usually burns at the temperature of 600 co approximately. the results show that the high soot mass in high load can be treated by raising the exhaust temperature and reached to greater than 600co. in the moderate load up to 70%, it is found that the soot mass emitted is not exceeding the (epa) standards in the first and second tiers. the exhaust temperature is high and the soot mass rate is to be low and easily treated. key words: soot, gravimetric method, diesel engine, air pollution, u. s. epa. (introduction)المقدمة غير نظامي وصـحيح يعاني بلدنا العزيز من مشكلة تلوث الهواء الناتج من حرق أنواع مختلفة من الوقود بشكل لكن النصيب األكبر مـن التلـوث يعـود إلـى , في محركات السيارات والشاحنات والمعامل واألفران وغيرها االنبعاثات الملوثة لمحركات االحتراق الداخلي المستخدمة في الـسيارات خـصوصا بعـد اسـتيراد الـسيارات المنتج لها من نواحي السيطرة على الملوثات والنواحي المستهلكة والمستعملة وغير المطابقة للمواصفات في البلد . التقنية البحث المقدم يهتم بقياس معدالت التلوث الدخاني الصادر من محركات الديزل ومقارنته بمقاييس وكالـة حمايـة ءة متوسط الضغط الفعـال وكفـا , ودراسة العالقة بينه وبين قدرة، استهالك الوقود النوعي epaالبيئة العالمية . المحرك فـي منظومـات االحتـراق ذات اللهـب االنتـشاري ) وهو جسيمات الكـاربون الـصلبة (عادة يتكون السناج )diffusion flames ( ،كما في محركات الديزل، التوربينات الغازية، المراجل البخارية في محطـات القـدرة يكون التماس بين الوقود والهواء قليل فـان في هذا النوع من اللهب . افران مصانع االسمنت والطابوق وغيرها ممرات دخول الوقود الى غرفة االحتراق تختلف عن ممر دخول الهواء لذلك تكون طبيعة هذا اللهب هو سناجي )sooting flame ( وعندما يكون معدل تكوين السناج)soot formation ( اكبر من معـدل تأكـسده)soot burnout (ود خارج غرفة االحتراقان اسفانه سوف يظهر بشكل دخ)kue,2005 (. ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٧ . السناج المنبعث من منظومات االحتراق ذات الوقود الهايدروكاربوني له دوريين مهميين جدا في الجانب البحثي تساعد كثيرا في انتقال الحرارة باالشعاع لذا فـان تكـوين ) high emissivity(االول انه يمتلك أنبعاثية عالية مات االحتراق لمحركات الديزل والتوربينات الغازية أمر غير مرغوب فيه النه يـساعد فـي السناج في منظو الثاني يساهم فـي تلـوث . أنتقال جزء كبير من الطاقة المتحررة عن طريق جدران غرفة االحتراق الى الخارج لهب االنتشاري اليوجد الهواء عند خروجه مع غازات العادم الى الجو الخارجي وذلك الن عملية االحتراق في ال فيها خلط مسبق للوقود مع الهواء والتماس بينهما يكـون قليـل، هـذا يـؤدي الـى تحلـل الوقـود حراريـا )thermal pyrolsis ( وبالتالي تنتج عنه انواع كثيرة جدا من المركبات الهايدروكاربونية التي لها القابليـة ان لنواة السناج المتكونة وخاصة المركبات ) growth phase(النمو تتكثف على سطح جسيمات السناج خالل طور وبسبب صغر قطـر (roger,2005) المعروفة بتأثيرها السرطاني الخطر ) ah(الهايدروكاربونية االروماتية وكالـة . فانها بسهولة تستنشق وتدخل الى الجهاز التنفـسي لالنـسان ) 200nm(هذه الجسيمات حيث يصل الى هذه الوثيقـة , على عادم محركات الديزل ]٣[ طبقت وثيقة الضريبة الصحية ٢٠٠٢ في عام epaة حماية البيئ تقول ان العادم الصادر من محركات الديزل سام يفسد الهواء ويتسبب في آثار صحية على المدى القصير مثـل لديزل يتسبب في أمراض الجهاز أما على المدى البعيد فأن عادم ا ). دوار وغثيان , السعال, تهيج الرئتين والعيون ( . التنفسي المزمنة وما يتصل بها من خطر السرطان ( هي طريقـة مباشـرة ) g/min(الطريقة التي أستخدمت في هذا البحث لقياس معدل كتلة السناج المنبعث direct gravimetric method (ة من العـادم حيث تم اصطياد جسيمات السناج المنبعث في المراحل المتاخر الذي يعمل كفلتر داخل انبوبة زجاجية مصنوعة من الزجـاج ) glass wool filter(بواسطة الصوف الزجاجي ، ويأخذ وزن السناج خالل فترة زمنية محددة عندما يصل المحرك الـى حالـة )pyrex glass(المقاوم للحرارة ان هذا الطريق في الحصول على المجاهيل هو في الظرف التشغيلي الخاص، علما ) steady state(االستقرار النه طريق مباشر التوجد فيه عمليات حسابية او تقربيـة فـي )eastwood,2000 (مفضل عند اكثر الباحثين حيث توجد فيها صعوبة بالغة فـي الحـصول علـى ) optical extinction methods(قبال التقنية البصرية وغيرها لذلك فهي تعطي نظرة ) referactive index(السناج ومعامل االنكسار الثوابت الفيزياوية مثل انبعاثية التي يتم الحصول فيها علـى ) bosh(وطريقة ) hartridge(ترج رطريقة هاكما في ) integral view(كلية light(ان نتائج كتلة السناج المقاسة بالتقنية البـصرية )dyer,1981(وجد الباحثين ). g/m3(كثافة السناج extinction method ( هي اكبر بمرتين او ثالث مرات من الكتلـة المقاسـة بالطريقـة المباشـرة الوزنيـة )gravimetric method( حيث درس الباحثين تكوين السناج عند احتراق حجم ثابت لخليط غني بالبروبـان ، ولكن مع ذلك فان الطريقـة . ب على الترتي.atm 4.4 و c0 420مع الهواء عند درجة حرارة وضغط ابتدائين ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٨ البصرية هي طريقة معتمدة في قياس سرعة السناج المتكون في مناطق اللهب وبتالي الحصول على زمن بقـاء .)leylegian,2008(السناج في كل منطقة من اللهب ):experimental part(الجزء العملي ار محرك الديزل والثاني هو منظومـة اصـطياد االول هو جهاز اختب , الجزء العملي يتألف من جزئين رئيسيين مفتوح تماما للوصول الى ) rack(اختبار المحرك تم عندما كان الحامل . وتجميع السناج المنبعث من المحرك اكبر سرعة للمحرك ثم ان زيادة الحمل المسلط على المحرك بشكل تدريجي نحصل منه على تغيـر بالـسرعة , بين اكبر سرعة واقل سرعة للمحرك , تسجيل ستة قراءات للمتغيرات المطلوبة وصوال الى اقل سرعة بحيث تم ومن ثم يخفض ) درجة حرارة العادم ومعدل كتلة السناج بالعادم , استهالك الوقود والهواء , السرعة, العزم( وهي الستة الـسابقة الحمل تدريجيا للوصول الى اكبر سرعة سابقة بحيث يتم في هذه المرحلة أعادة تسجيل القراءات بعدها يتم أدخال هذه . للمتغيرات بعدها يأخذ متوسط القراءات لكي تكون النتائج المحصل عليها اكثر دقة ووثوقا المتغيرات المقاسة من الجهاز في المعادالت الخاصة بايجاد بعض معالم األداء المهمة للمحـرك مثـل القـدرة . متوسط الضغط الفعال والكفاءة الحرارية, قود النوعياستهالك ال, الوقود\نسبة الهواء, المكبحية (rig test)جهاز االختبار ) ١( وحـدة , محرك ديزل رباعي االشـواط , التركيب األساسي للجهاز المعد لالختبار يتكون من ثالث أجزاء رئيسية ) .tq education and triaing ltd(الجهاز مصنع من قبل شركة . الداينموميتر الهيدروليكي ووحدة القياس ). model td115(موديل , االنكليزية (diesel engine)محرك الديزل) ١-١( المصنع من قبل نفس الـشركة موديـل , المحرك الذي تم اختباره نوع ديزل رباعي األشواط ذو اسطوانة واحدة )model td111 ( الجدول رقم أما مميزات المحرك الفنية فهي كما في)١(. (hydraulic dynamometer unit)ة الداينموميتر الهيدروليكي وحد) ٢-١( الجهاز يتكون من جزئيين رئيسين هما الجزء , يوضح مخطط الداينموميتر الهيدروليكي المستخدم )١(الشكل رقم للـسيطرة علـى (needle valve a)يستخدم صمام ابري . (stator b ) والجزء الثابت (rotor d )الدوار للمحرك (crank shaft)عمود المرفق . كلداخل للداينموميتر وبالتالي التحكم بالحمل المسلط على المحرالماء ا ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٩ مع الجزء الدوار للداينموميتر وبهذا تنتقل طاقة المحرك من الجزء الـدوار (coupling)يربط بواسطة مزدوج يوجـد , (stator b)ى الجزء الثابت الخارجيإلى المائع الموجود بين الجزء الدوار والجزء الثابت ومن المائع إل إلـى المقاومـة (stator b) ينقل حركة الجزء الثابـت مثبت على الجزء الخارجي (cable e)هناك حبل (f)النوابض. والتي بدورها تعطي مقدار من الفولتية تترجم وتعاير للحصول على العزم المكبحي (h)المتغيرة يـساعد فـي (c)الـصمام . وهي في وضع شد دائـم (stator b)ي للجزء الثابت مثبتة على السطح الخارج .السيطرة على كمية الماء الخارجة من الداينموميتر فهو بالتالي يساعد في تنظيم حمل المحرك (instrumentation unit)وحدة القياس ) ٣-١( ه الوحدة مع جميع أنواع المحركـات تستخدم هذ (model td114 ) موديل يوضح لوحة القياس)٢(الشكل .المراد اختبارها على الجهاز ( measurement of fuel consumption )قياس استهالك الوقود ) ٤-١ ( اعتمد في قياس استهالك الوقود على مبدأ , يوضح المنظومة المستخدمة لقياس معدل استهالك الوقود )٣(الشكل .لمستهلك مع الزمنأساسي وهو قياس حجم ثابت للوقود ا (measurement of air consumption)قياس استهالك الهواء ) ٥-١( ) hagenpoiseuille(تم االعتماد على معادلة . الجهاز المستخدم في قياس استهالك الهواء)٤ (لالشكيوضح . اقي داخل األنبوب الذي نضمن فيه جريان طب (capillary tube)للجريان الطباقي واستخدام األنبوب الشعري ( collecting soot mass system)منظومة تجميع السناج المنبعث ) ٢( هي الخطوة المهمة (post exhaust )قياس كتلة السناج المنبعث من المحرك في المراحل المتأخرة من العادم جسيمات السناج . ال متغيرة في أنجاز البحث حيث تم قياس كتل مختلفة من السناج المنبعث من المحرك عند أحم موضوع داخل أنبوبـة تجميـع الـسناج (glass wool filter)تم اصطيادها باستخدام فلتر الصوف زجاجي (soot collecting piece) مصنعة من زجاج مقاوم للحرارة ( pyrex glass) والتي تحتوي فـي مقـدمتها حصلنا على . )٥(الشكل غازات العادم الحظ موزعة بالتساوي لدخول ) d=7mm(على سبعة ثقوب بقطر .كتلة السناج بواسطة أخذ وزن أنبوبة التجميع قبل وبعد االصطياد للسناج ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٠ ) soot mass measurement( قياس كتلة السناج ١-٢ وتعبئتها بفلتـر الـصوف ) pyrex glass(أنبوبة تجميع مصنعة من زجاج مقاوم للحرارة ) ٦(تم تحضير عدد لمدة سـاعة داخـل فـرن ) co 200(، بعد ذلك تم تسخينها عند درجة حرارة )glass wool filter(اجي الزج حتى تصل إلـى ) desiccator(كهربائي الزالة اي رطوبة موجودة بالصوف الزجاجي ثم تحفظ داخل حافظة .درجة حرارة الغرفة . (wiggen hauser)قياس الوزن االبتدائي ألنبوبة التجميع باستخدام ميزان حساس نوع توضـع , عند تحميل المحرك والوصول إلى حالة االستقرار التي يؤخذ عندها القراءة لمعـامالت أداء المحـرك . أنبوبة التجميع داخل المكان المخصص لها بالمراحل المتأخرة من العادم بوب العـادم وتوضـع فـي دقائق تُستخرج العينة من أن ١٠حالما تنتهي الفترة المخصصة لتجميع السناج وهي (desiccator).الحافظة .لكل أنبوبة تجميع) ٤(إلى ) ٢(أخذ أنبوبة تجميع اخرى وإعد الخطوات من قياس الوزن النهائي لكل أنبوبة تجميع مع الصوف الزجاجي باستخدام نفس الميزان وبهذا يتم حساب كتلة السناج وهكـذا . جميع في المكان المخصص لها في منظومة العادم عن طريق اخذ فرق الوزن قبل وبعد وضع انبوبة الت بين اقل حمل واقصى حمل مسلط على المحرك تم تسجيل ستة قراءات الداء المحرك وستة قراءات لمعدل كتلـة السناج حيث توضع أنبوبة التجميع في كل مرة بالمكان المخصص لها في المراحل المتأخرة من العادم هذا فـي الحمل أما في حالة النزول مع الحمل ايضا يتم أعادة تسجيل القراءات الـستة ألداء المحـرك حالة الصعود مع اذن القـدرة الخارجيـة . ومعدل كتلة السناج وبعدها يتم أخذ متوسط كل قراءة ألداء المحرك ومعدل كتلة السناج g/kw(السناج بالوحدات الداء المحرك يمكن الحصول عليها مع تغير الحمل وبهذا سوف نعبر عن معدل كتلة hr .( (result and discussion)النتائج والمناقشة -٤ مفتوح بالكامل والمحرك في اعلى سرعة لـه فـان زيـادة ) rack(تم أختبار محرك الديزل عندما كان الحامل ريجي ايضا وصوال ينتج عنه نقصان بالسرعة تد , بواسطة التحكم بكمية الماء الداخلة للداينموميتر , الحمل تدريجياً متوسـط (يعطي نضرة عامة عن معالم االداء المهمة ) 6b(و ) 6a(الشكل . ألقل سرعة للمحرك عند اعلى حمل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣١ a/f( الهـواء \نـسبة الوقـود , )kg/kw hr(استهالك الوقود النوعي بال , )kpa(الضغط الفعال بال ratio( , الكفاءة الحرارية)%ŋ ( ك لكل والقدرة المكبحية للمحر)cm2 ( لمحـرك الـديزل ) من مساحة المكـبس يوضح ان ) 6a(الشكل . المراد قياس تركيز كتلة السناج المنبعث منه باالعتماد على تغير سرعة المكبس للمحرك أعلى قدرة مكبحيـة . عند اقصى حمل ) 3:1(عند اقل حمل للمحرك الى ) 28:1(الوقود تتغير من : نسبة الهواء ). 22:1 -15:1(وقود تتراوح من : عند نسبة هواء) %45(واعلى كفاءة حرارية ) w/cm2 113.4 (للمحرك . كذلك ان موقع أعلى قدرة للمحرك يكون عند أعلى كفاءة حجمية او بمعنى اخر عند أعلى كتلة هواء داخلة لـه kg/kw 204.6 (نستنتج منه ان موقع أعلى كفاءة يكون عند أقل استهالك للوقود النوعي يصل الى ) 6b(الشكل hr( ,حيث يتميز محرك الديزل بأنه أقتصادي في كمية الوقود المستهلك . مـع تغيـر الحمـل ) g/kw hr( يوضح العالقة بين تركيز كتلة السناج المنبعث من المحرك مقاسة )٧(الشكل حمـل ويـزداد نالحظ فيه ان معدل كتلة السناج قليل جدا عندما يعمل المحرك مـن دون . المسلط على المحرك معدل كتلة السناج تدريجيا مع زيادة الحمل حتى يصل الى أعلى كتلة في االحمال العالية جدا التي تـصل الـى المسيطر علـى كميـة المـاء الداخلـة ) needle valve(نحصل عليها عندما يكون الصمام االبري , )95%( التـي ) %95-%70(تلة السناج باالحمال العالية ويعود سبب زيادة ك , )1(الشكل للداينموميتر مفتوح كليا الحظ الى أمرين؛) rpm(دقيقة\دورة) 2000-1750(تقابل سرعة محرك الوقود ومعدل كتلة السناج مـع \الذي يوضح العالقة بين نسبة الهواء ) ٨( االول يمكن تفسيره باالستعانة بالشكل استهالك الوقود النوعي ومعدل كتلة السناج مـع الذي يوضح العالقة بين ) ٩(تغير الحمل على المحرك والشكل النقص الكبير الذي يحدث في كتلة الهواء الداخل للمحرك في االحمـال ) ٨(حيث نالحظ من الشكل . تغير الحمل يشير في نفس الوقت الى زيادة كبيرة في استهالك الوقود النوعي نستنتج من ذلك ان جـزء ) ٩(العالية والشكل داخـل غرفـة االحتـراق ) thermal(ديزل اليحترق وأنما يعاني من عملية تكسير حراري كبير من وقود ال soot(وتحوله الى انواع كثيرة ومختلفة من المركبات الهايدروكاربونية والتي تكون سببا في تكـوين الـسناج formation ( وبمعدالت اكبر من معدالت تأكسده)soot burnout (مقاسة للسناج في لذلك يكون معدل الكتلة ال ).٧(العادم كبير الشكل في األحمال العالية فتكون غيـر كافيـة ألكـسدة ) 400c( الثاني انخفاض درجة حرارة العادم حيث تصل الى السناج الخارج وبهذا فان انخفاض درجة الحرارة سوف يكون سببا في تجمع جسيمات السناج والتـصاقها مـع الذي يوضح عالقة كل من درجة حرارة العادم ومعـدل كتلـة الـسناج )١٠(بعض وكبر حجمها الحظ الشكل المخطط كذلك يبين ان معدل كتلة السناج في االحمل المتوسطة . المنبعث من العادم مع تغير الحمل على المحرك ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٢ تقريبا يكون اقل حيث تساعد هذه الدرجة الحرارية مع توفر كمية اوكسجين قليلة ) 700co(وعند درجة حرارة عندما قام بتجهيز كتلة معينـة مـن ]٧[في العادم على حرق السناج وأنخفاض كتلته وهذا ماتوصل اليه الباحث ووضعها داخل فرن كهربائي ودرس ثـاثير معـدالت درجـة *سناج الديزل وكتلة اخرى من أسود الكاربون ). 580co(الحرارة عليها حيث وجد ان سناج الديزل يبدأ يحترق عند درجة حرارة ان ارتفاع معدل كتلة السناج المنبعث من المحرك في االحمال العالية قد انعكس سلبا على قدرة وكفاءة المحرك الذي يوضح العالقة بين القدرة المكبحية ومعدل كتلة السناج مع تغير الحمـل )١١(الشكل كما هو المالحظ في دل كتلة السناج مع الحمل حيـث نالحـظ مـن كـال الذي يوضح العالقة بين كفاءة المحرك ومع )١٢(والشكل .الشكلين األنخفاض الكبير في قدرة وكفاءة المحرك , )kw 4.36(للمحرك فان قدرة المحرك تصل الى اعلى قيمـة لهـا ) %69 -%20(اما في االحمال المتوسطة كـون مـصحوبا وهـذا ي )١٢(الشكل كما في ) %45( وكذلك فان كفاءة المحرك تصل الى )١١(الشكل الحظ والسبب في هذا ان معدالت تكـوين ) g/kw hr 0.924(بانخفاض كتلة السناج المنبعث بحيث يصل تقريبا الى كذلك )٩(الشكل السناج في هذه االحمال أقل من االحمال العالية خصوصا مع انخفاض استهالك الوقود النوعي اما ارتفـاع . من معدالت االكسدة في االحمال العالية فأن معدالت االكسدة واالحتراق للسناج المتكون تكون اكبر يساعد كثيرا في اكسدة السناج في العـادم ) co 700(درجة حرارة العادم في االحمال المتوسطة حيث تصل الى . )١٠(الشكل الحظ , مع وجود كمية اوكسجين قليلة عة االصباغ واالحبـار واالطـارات في صناعات عديدة منها صنا) carbon black( يدخل أسود الكاربون * توجد هناك طرق مختلفة النتاجه عن طريق حرق وقود هايدروكاربوني ثقيل يوجـد , وكافة الصناعات المطاطية . في بلدنا العراق أكثر معمل ألنتاجه (عند مقارنة معدل كتلة السناج المنبعث من المحرك مع مقاييس وكالة حمايـة البيئـة , في االحمال العالية environmental protection agency, epa ( للمحركات التي قدرتها اقـل مـن)8 kw (]نجـد ان , ]٨ اما في االحمال المتوسطة نجد ان المحرك لـم , المحرك قد تجاوز المقاييس المسموح بها بعشرة اضعاف تقريبا ولكنـه قـد تجـاوز الحـدود ) tier2(والطبقة الثانية ) tier1(يتجاوز الحدود المسموح بها في الطبقة االولى المقصود بالمقيـاس فـي الطبقـة االولـى ). tier4(والطبقة الرابعة ) tier3(المسموح بها في الطبقة الثالثة )tier1 ( هو المقياس المضوع من قبلepa من عام )(واما الطبقة الثانية ) 2005-2000tier2 ( فهي تمتـد ).١(الحظ الملحق , )2008-2005(من عام ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٣ ) 3600 -3000(والتـي تقابـل سـرعة محـرك ) %19-%5(اما في االحمال القليلـة التـي تتـراوح بـين الخارجة من المحرك والسبب في هذا أن كتلة الوقـود قليلـة ةنالحظ انخفاض الكفاءة والقدر ) rpm(دقيقة\دورة المتحررة من عملية االحتراق وهذا وبالتالي انخفاض الطاقة ) ٩،١٠(مقارنة مع كتلة الهواء المتوفر الحظ الشكل العالية توفر كميـة هـواء ودرجـة ) الوقود /الهواء(يفسر انخفاض كتلة السناج عند األحمال القليلة بحيث نسبة .حرارة مالئمة الحتراق السناج المتكون )conclusion( االستنتاجات -٥ ان معدالت تكوين الـسناج اكبـر مـن ارتفاع معدل كتلة السناج المنبعث في االحمال العالية يشير الى • . معدالت التاكسد وهذا يكون سببا في نقصان قدرة المحرك وكفاءته تقريبا ألنه يكون مصحوب بارتفـاع % ) ٦٩إلى % ٢٠( يجب تشغيل المحرك عند حمل متوسط من • لة حماية البيئة الكفاءة والقدرة الخارجة وانخفاض معدل كتلة السناج المنبعث بحيث التتجاوز مقياس وكا epa 1( المسموح به وهو g/kw hr ( في الطبقة االولى)tier 1.( يساعد كثيـرا فـي اكـسدة الـسناج ) c٧٠٠(إلى ) c٤٠٠(من , في األحمال العالية , رفع درجة العادم • . وبالتالي تقليل كتلته (references) املصادر -٦ 1kue, k-y., principles of combustion, copyright by wileyinterscience, 2005. 2roger, a. h., and merlin h. k., energy: its use and the environment, copyright by john wiley and sons, inc., 2005. 3u. s. environmental protection agency ( epa), health assessment document for diesel engine exhaust, prepared by national center environmental assessment, washington, dc, for the office of transportation and air quality; epa/600/8-90/057f, 2002. 4eastwood, p., critical topics in exhaust gas after– treatment, research studies press., 2000. 5dyer, t.m., and flower, w.l., aphenomenological description of particulate formation during constant volume combustion, particulate carbon formation during combustion, an inter. symp. sponsored by g.m. research lab., edited by siegla, d.c. and smith, g.w., plenum press, new york, pp. 363, 1981. ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٤ 6leylegian, j.c., soot formation in aerodynamically strained methane–air and ethylene–air diffusion flames with chloromethane addition, combustion and flames, vol. 152, pp. 144-153, 2008. 7noirot, r., gilot, p., gadiou, r., and prado g., control of soot emission by filtration and post combustion, combustion science and technology, vol. 95, pp. 139-160, 1994. 8the web address for the epa green vehicle guide is www. epa. gov/ emissweb/. خصائص احملرك الفنية) ١(جدول رقم tq education and triaing ltd. manufacturer diesel, four strokes cycle 1 vertical number of cylinder 70 mm bore 65 mm stroke 15 compression ratio 250 cm3 swept volume natural aspiration charging ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٥ .كييوضح خمطط وحدة الداينموميتر اهلايدرولي) ١(الشكل (modeltd114 )يوضح جهاز وحدة القياس موديل ) 2(الشكل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٦ . الوقود معدل استهالكيوضح املنظومة املستخدمة لقياس) ٣(الشكل .يوضح اجلهاز املستخدم يف قياس استهالك اهلواء) ٤(الشكل .يوضح أنبوب جتميع السناج) ٥(الشكل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٧ 1 2 3 4 5 6 a/f ratio (bp(w/cm20 20 40 60 80 100 120 a/f ratio η % ηv % bp(w/cm2) )aيوضح معامالت االداء للمحرك عند تغري السرعة) ٦. 1 2 3 4 5 6 up m/min bmep(kpa) bsfc(kg/kwhr) 0 500 1000 1500 2000 engine performance chart at variable speed up m/min bmep(kpa) bsfc(kg/kwhr) .لمحرك عند تغري السرعةيوضح معامالت االداء ل) b٦(الشكل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٨ 0.1 1 10 100 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 engine spee d (rpm) s oo t m as s ra te (g /k w h r) . كتلة السناج املنبعث مع تغري احلمل معدلعالقة) ٧ (الشكل 0.1 1 10 100 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 engine speed (rpm) s o o t m as s ra te ( g /k w h r) 0 5 10 15 20 25 30 35 a /f r at io soot rate a/f ratio .الوقود وكتلة السناج مع تغري احلمل\العالقة بني نسبة اهلواء) ٨(الشكل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣٩ 0.1 1 10 100 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 engine speed (rpm) s oo t m as s ra te (g /k w h r) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 s fc (k g/ kw h r) soot rate sfc . العالقة بني استهالك الوقود النوعي وكتلة السناج مع تغري احلمل) ٩(الشكل 0.1 1 10 100 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 engine speed (rpm) s o o t m as s ra te ( g /k w h r) 200 300 400 500 600 700 800 e xh au st te m pe ra tu re c soot rate temp. .رجة حرارة العادم وكتلة السناج مع تغري احلملالعالقة بني د) ١٠(الشكل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٤٠ 0.1 1 10 100 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 engine speed (rpm) s o o t m as s ra te ( g /k w h r) 0 1 2 3 4 5 b ra ke p o w er ( kw ) soot rate bp(kw) . وكتلة السناج مع تغري احلملالقدرة املكبحيةالعالقة بني ) ١١(الشكل sfsdgadg 0.1 1 10 100 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 engine speed (rpm) s oo t m as s ra te (g /k w h r) 0 5 10 15 20 25 30 35 40 45 50 th er m al e ff ic ie nc y % soot rate η % العالقة بني كفاءة احملرك وكتلة السناج مع تغري احلمل) ١٢(الشكل ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٤١ appendix1: past and current pollutants emissions according to u s al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 165 the use of the control charts to control the dimension of the clay brick units lecturer sada a. hasan, dr.tumadhir m., borhan civil engineering department, university of al-qadissiyah ,iraq e-mail: sada.hasan@qadissuni.edu.iq . tumadhir_borhan@qadissuni.edu.iq received 3 december 2013 accepted 27 march 2014 abstract some manufactured material properties are expected to have unavoidable shifting in its average value for many reasons, however, they are still able to meet the established specifications. this case occurs when the standard deviation of the process at the various average values is very small compared to the difference between the upper and lower specification limits. on the other hand, any results out of these limits indicates that the efficiency of the process changes and the reasons have to be investigated and corrected .in this study, al-qadissiyah brick factory was adopted to examine the acceptance of the produced brick, in terms of its dimensions, according to iraqi specifications. control charts were plotted for this purpose. two types of charts were used, the mean and the standard deviation charts. the upper and the lower limits (ucl andlcl) of each brick dimension were plotted and discussed. the results showed that the lower, the upper limits and the mean value for all dimensions are within the iq specifications limits and the process is under control. however, the results of the length show that there is one point outside the lcl at the mean chart and one point outside the ucl at the standard deviation chart. this due to the chance causes, as it is only one point from thirteen patches .these charts can be adopted by the factory to show the production process and can be used in the future to investigate the mean of any measured patch. keywords: quality control, control charts, mean chart, standard deviation chart, brick dimensions. استخدام لوحات السيطرة للسيطرة على إبعاد الطابوق الطيني الخالصة من المتوقع ان تتغير خواص بعض المواد المصنعة وتتحول في متوسط قيمتها ألسباب كثيرة ,ومع ذلك فأنها ماتزال قادرة على تلبية ف المعياري للعملية عند المتوسط الحسابي لمختلف القيم صغير جدا عندما يكون االنحراالمواصفات المعمول بها . تحدث هذه الحالة مقارنه بالفرق بين حدود المواصفة العليا والدنيا . من ناحية أخرى فان أي نتيجة خارج هذه الحدود تعطي مؤشر بان كفاءة العملية دراسة اعتمد معمل طابوق القادسية لفحص قبول إنتاجه من الطابوق من تتغير ويجب البدا بالتحقق عن األسباب وتصحيحها. في هذه ال mailto:sada.hasan@qadissuni.edu.iq mailto:tumadhir_borhan@qadissuni.edu.iq al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 166 حيث اإلبعاد وفقا للمواصفة العراقية . وقد رسمت لهذا الغرض خرائط السيطرة وقد استخدمت نوعين من خرائط السيطرة ,خريطة رسمها ومناقشتها . المتوسط وخريطة االنحراف المعياري , الحدود العليا والدنيا لكل أبعاد الطابوق قد تم مخططات السيطرة للمتوسط واالنحراف المعياري لكل من الطول والعرض والسمك للطابوق قد رسمت وبينت ان الحدود العليا والدنيا والمتوسط الحسابي لكل اإلبعاد ضمن المواصفات العراقية والعملية اإلنتاجية تحت السيطرة . لوحة المتوسط للطول بينت بان هناك نقطة واحدة خارج الحدود الدنيا للمخطط بينما بينت لوحة االنحراف المعياري بان هناك نقطة 03واحدة اعلى من الحدود العليا وبعد إجراء التحقق ألموقعي تبين ان هذه النتائج تعود ألسباب صدفية كونها نقطة واحدة من اصل يطرة على العرض قد رسمت والنتائج تشير بان النقاط كلها ضمن الحدود وتتوزع بشكل عشوائي حول الخط خرائط الس .عينة المركزي واتجاه النقاط هذا يعطي مؤشر بان العملية اإلنتاجية ضمن السيطرة ونفس النتيجة قد تم تحصيلها لخرائط السيطرة على لتبين نتائج عمليات اإلنتاج ويمكن ان تستخدم في المستقبل لتصحيح معدل نتائج السمك . هذه الخرائط من الممكن اعتمادها في المعمل أي وجبة مقاسه كما تساعد على مقارنة النتائج الجديدة للفحوصات بالحدود المرسومة في خرائط هذا البحث . introduction the quality control is one of the main functions in all organizations as a tool that is responsible for the accomplished work in each stage of production process in order to make sure that the final results and the estimated results are identical. this will help to detect the deviation early so remedies can be deployed quickly. the quality of the product is a result of the quality of the process of production and the statistical quality control is necessary to detect changes in the behavior of these processes. the factories of different materials produce a large amount of products. this may causes shifting in their specifications. to control the quality of their products and testing the quality characteristics, many of laboratories are established inside the factory. since one of the basic tools in the control processes are the charts to monitor the quality of the products, as if the output acceptable, it allows for the manufacturing process to continue. however, if the output is unacceptable, it means that the process is out of control, which requires corrections. these charts are considered one of the important functions of the control in management of the structures in general and the construction industry factories in particular. the most widely used control charts are the shewhart control charts[ gibra,1975],[ box,2011] that developed to distinguish between common and special-cause variation. the special cause variation was measured by a change in the mean of process. these shewhart charts are known as the ̅-chart (average-chart or mean–chart), the r-chart (range–chart) and the σ-chart (standard deviation chart) [leavenworth,2000],[ montgomery,2007] . the brick unites produced in iraqi factories are mostly varies in its dimensions and may not meet the standard specification. in this case, it is very helpful to apply the control charts in these factories to eliminate this problem. to control the upper and the lower limits of the brick dimensions in a specific factory in iraq (alqadissiyah factory), these charts were used in this study. the charts used are the mean ( ̅-chart) and standard deviation(σ-chart) charts. this will help to reduce or eliminate the variation outside the limits in the brick dimensions if it is caused by common causes not by chance causes[ heizer,2008] . al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 167 collecting data the collected data for quality control purposes is obtained directly from the factory. thirteenth patches of brick units that produced during one month were taken from the factory. each of them has twenty-four brick units as recommended by the iraqi specifications no. 24. the dimensions of the units were measured according to method stated by iraqi specifications [iqsno.24 , 1988] .tables 13show the length, width and the thickness of the selected brick units for these patches. control charts the ̅-chart plots the process averages of each patch from the production against three horizontal lines. the central line represents the average value of the mean of each patch. while the σ-chart plots the process standard deviation of each patch from the production against three horizontal lines. the central line represents the average value of the standard deviation of each patch. the other two lines are known as upper and lower control limits (ucl & lcl). the mean and the standard deviation are calculated as shown in table 4.the eqs.(1-3) and (4-6) represent the limits for the ̅-chart and σchart respectively [ altaai,2008] . ucl= ̿+a1 ̅ ………………………………………………………………………………………………(1) cl= ̿ ………………………………………………………………………………………………(2) lcl= ̿a1 ̅ ……………………………………………………………………………………………….(3) ucl=b1. ̅ ……………………………………………………………………………………………….(4) cl= ̅ ……………………………………………………………………………………………….(5) lcl=b2. ̅ ………………………………………………………………………………………………(6) where: a1, b1, b2 is a constant and predetermined values [7] . ̿is the average value of the mean ̅is the average value of the standard deviation results and discussion figures (1 -3) show the control charts for the mean and the standard deviation of the length, width and the thickness respectively. it can be seen that the lower, the upper limits and the mean value for all dimensions are within the iq specifications limits and the process is under control. figure (1a) shows the control chart for the mean of the length . it can be seen that there is one point outside the lcl. figure (1b) shows the control chart of the standard deviation and there is one point outside the ucl. after the site investigation, these results can be attributed to the chance causes, as it is only one point from thirteen patches. the control charts for the width, using the mean and the standard deviation charts, are shown in figure 2 (a and b) respectively. the results indicated that all points are within the limits and distributed randomly around the centerline. the trend of the points indicates that the production process is under control. the same results are obtained for the thickness as shown in fig. 3 (a and b). al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 168 these charts can be adopted by the factory to show the production process and can be used in the future to investigate the mean of any measured patch. this will help to compare the new results with the charts limits stated in this study. if the results of the new patch are outside the limits, we have to study the cause and again we have to measure a second patch and compare it with the limits. if the results obtained from the second patches are similar to the previous one (the mean is outside the limits), then the production process is out of control and should be corrected. however, the number of the brick unites in the patch, specified by the iq specifications, for measuring the dimensions of the brick unites (24 unites)is relatively high as shown in fig.4(a and b). this increase the chance for the patch to pass the test successfully. as a result, it can be concluded that changing the specifications of the brick dimensions is urgent to give an accurate indication about the quality of the process of the production in the brick unites factories. conclusion on the basis of the results obtained from the analysis of the real data of the brick dimensions, we can conclude that the mean value for all dimensions is within the iq specifications limits and the process is under control.the control charts presented in this study can be used to help the factoryto investigate the mean of any measured patch in the future. it can be concluded that there is a need to change the iq specifications regarding the number of the brick unites that have to be examined for its dimensions, as the current number is relatively high and give more realistic results. references [1] altaai, y. h. and m. a. alajily (2008). quality management systems in the productivity organization. iraq. [2] box, g. e. p. and w. h. woodall (2011). "innovation, quality engineering, and statistics." quality engineering 24(1): 20-29. [3] gibra, i. n. (1975). "recent developments in control chart techniques." journal of quality technology 7(4): 183-192. [4] heizer, j. h. and b. render (2008). operations management, pearson education india. [5] iqsno.24 (1988). standard methods for physical and chemical tests and sampling of building bricks in iraq. [6] leavenworth, r. s. and e. l. grant (2000). statistical quality control 7/e, tata mcgraw-hill education. [7] montgomery, d. c. (2007). introduction to statistical quality control, wiley. com. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 169 table 1: the measured length of the selected unites table 2: the measured width of the selected unites 1 24.13 23.75 24.2 24.15 23.8 24.3 24.4 24.08 23.4 24.13 24.01 23.97 23.75 23.95 23.4 24.07 24.4 23.8 24.15 24.13 24.07 24 24.13 24.14 2 24.01 24.13 23.97 23.95 24.13 23.75 24.2 24.15 23.8 23.4 24.13 23.95 24.97 24.13 23.75 23.8 24.07 24.13 23.95 24.13 24.15 23.75 24.01 23.8 3 23.97 24.13 24.13 23.75 24.3 24.16 23.75 24.3 24.4 24.1 23.5 24.2 24.15 23.85 23.95 24.25 24.15 23.9 24.18 24.5 23.8 24.18 24.4 23.9 4 24.25 24.23 24.4 24.1 23.95 24.2 24.15 24.34 24.3 24.1 24.01 24.07 24.02 24.15 24.01 24.2 24.15 23.8 23.98 24.2 23.99 23.8 24.01 23.85 5 23.9 23.85 23.95 23.8 24.12 24.13 23.65 23.85 23.65 23.98 24.15 24.1 23.75 23.85 24 24.1 23.82 24.01 23.98 23.95 23.85 24.1 24.2 24.15 6 23.75 24.08 24.06 23.9 23.85 24.02 24.08 24.13 23.95 24.1 24.01 23.85 23.9 23.95 24.1 24.12 24.1 24.08 23.95 23.8 23.78 23.95 24.1 24.12 7 24.12 24.07 23.85 24 23.75 24.3 24.4 24 23.6 24.12 23.653 24.03 24.2 24.123 23.85 24.035 24.13 24.21 24.2 24.12 24.1 24.11 23.85 23.8 8 24.1 23.8 23.95 23.75 24.2 23.98 23.75 24.07 23.85 23.9 23.8 23.95 24.08 24.12 23.8 23.9 24.13 24.06 24.13 24.12 24.12 24.07 24.05 24.13 9 23.85 23.65 24.08 23.95 23.8 23.4 24.13 23.85 24.15 24.04 23.8 23.85 23.95 23.9 23.85 23.85 23.95 24.12 24.1 23.75 23.8 23.5 23.65 23.7 10 23.97 24.12 24.14 24.08 23.85 24.15 24.04 23.97 24.25 23.9 23.5 24.2 23.95 23.75 23.95 23.9 23.9 24.15 23.85 24.4 23.9 24.13 23.95 24.12 11 24.25 24.1 24.08 23.98 23.95 24.1 24.12 24.25 24.2 23.8 24.01 24.07 24.18 24.15 24.08 23.95 23.85 24.02 24.15 24.01 23.85 23.9 24.18 23.85 12 23.95 24.13 23.75 24.14 24.12 23.8 23.68 23.95 24.04 24.12 24.15 24.1 23.95 24.12 24.12 24.07 24.15 23.75 23.85 24.2 24.15 23.8 23.98 24.2 13 24.1 24.01 24.07 23.75 23.85 24.15 24.04 23.85 23.95 23.8 23.85 23.85 24.3 24.31 24 24.016 24.3 24.18 23.86 23.9 24.12 24.125 23.95 24.01 2418 19 20 21 22 2312 13 14 15 16 176 7 8 9 10 11unit no batch no 1 2 3 4 5 1 11.55 11.5 11.65 11.5 11.5 11.16 11.42 11.52 11.53 11.5 11.35 11.75 11.61 11.16 11.6 11.6 11.53 11.52 11.42 11.61 11.75 11.35 11.42 11.51 2 11.35 11.3 11.52 11.14 11.75 11.5 11.35 11.75 11.6 11.17 11.5 11.65 11.5 11.5 11.16 11.6 11.45 11.55 11.35 11.41 11.16 11.5 11.35 11.65 3 11.5 11.45 11.7 11.55 11.43 11.18 11.71 11.62 11.65 11.75 11.62 11.16 11.35 11.5 11.57 11.42 11.6 11.65 11.55 11.45 11.5 11.63 11.65 11.4 4 11.75 11.62 11.55 11.16 11.35 11.28 11.16 11.6 11.5 11.42 11.65 11.5 11.6 11.5 11.35 11.53 11.45 11.5 11.16 11.4 11.45 11.65 11.5 11.6 5 11.5 11.35 11.45 11.5 11.13 11.6 11.4 11.45 11.35 11.16 11.25 11.45 11.5 11.35 11.65 11.35 11.4 11.55 11.3 11.14 11.16 11.4 11.5 11.65 6 11.56 11.6 11.66 11.5 11.75 11.45 11.35 11.4 11.55 11.6 11.45 11.14 11.6 11.16 11.55 11.75 11.45 11.35 11.4 11.54 11.23 11.35 11.53 11.54 7 11.75 11.5 11.76 11.6 11.5 11.42 11.65 11.6 11.35 11.53 11.55 11.43 11.18 11.71 11.6 11.65 11.55 11.65 11.34 11.45 11.45 11.55 11.43 11.5 8 11.65 11.55 11.54 11.45 11.35 11.16 11.25 11.54 11.65 11.54 11.3 11.12 11.16 11.54 11.55 11.45 11.5 11.16 11.65 11.35 11.35 11.3 11.45 11.6 9 11.55 11.16 11.35 11.16 11.25 11.45 11.43 11.18 11.43 11.54 11.65 11.34 11.43 11.16 11.4 11.45 11.45 11.45 11.5 11.65 11.45 11.24 11.45 11.4 10 11.45 11.5 11.55 11.6 11.45 11.14 11.16 11.54 11.35 11.16 11.23 11.24 11.22 11.3 11.14 11.16 11.4 11.45 11.5 11.34 11.54 11.35 11.4 11.16 11 11.34 11.36 11.5 11.35 11.53 11.55 11.54 11.5 11.65 11.12 11.23 11.3 11.34 11.45 11.45 11.55 11.45 11.35 11.53 11.25 11.4 11.55 11.45 11.26 12 11.45 11.35 11.16 11.25 11.5 11.5 11.34 11.16 11.55 11.43 11.18 11.71 11.35 11.35 11.3 11.45 11.35 11.16 11.55 11.45 11.5 11.63 11.8 11.26 13 11.4 11.55 11.6 11.16 11.25 11.6 11.27 11.16 11.12 11.16 11.54 11.55 11.45 11.24 11.23 11.26 11.34 11.18 11.23 11.4 11.45 11.65 11.5 11.17 5unit no batch no 1 2 3 4 176 7 8 9 10 11 12 13 14 15 16 2418 19 20 21 22 23 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 170 table 3: the measured thickness of the selected unites 1 7.65 7.5 7.56 7.7 7.5 7.6 7.57 7.55 7.45 7.47 7.6 7.6 7.6 7.65 7.5 7.5 7.6 7.57 7.54 7.57 7.56 7.6 7.6 7.5 2 7.5 7.75 7.57 7.65 7.58 7.7 7.56 7.56 7.62 7.45 7.67 7.5 7.45 7.63 7.59 7.38 7.45 7.6 7.43 7.65 7.54 7.55 7.54 7.47 3 7.65 7.54 7.47 7.57 7.56 7.6 7.36 7.59 7.38 7.56 7.45 7.5 7.68 7.5 7.55 7.58 7.57 7.63 7.65 7.54 7.65 7.63 7.5 7.5 4 7.65 7.5 7.55 7.58 7.55 7.56 7.62 7.64 7.55 7.68 7.5 7.56 7.65 7.6 7.7 7.56 7.55 7.5 7.63 7.7 7.56 7.57 7.45 7.66 5 7.56 7.34 7.56 7.57 7.67 7.5 7.55 7.75 7.55 7.44 7.56 7.45 7.56 7.56 7.5 7.4 7.5 7.67 7.36 7.58 7.61 7.57 7.56 7.55 6 7.17 7.27 7.55 7.67 7.47 7.55 7.75 7.54 7.56 7.45 7.5 7.47 7.61 7.55 7.56 7.5 7.4 7.55 7.54 7.58 7.54 7.5 7.55 7.6 7 7.76 7.67 7.46 7.57 7.78 7.61 7.3 7.44 7.5 7.56 7.55 7.55 7.6 7.45 7.46 7.55 7.56 7.63 7.45 7.45 7.45 7.55 7.55 7.6 8 7.55 7.56 7.62 7.66 7.57 7.45 7.66 7.5 7.6 7.45 7.56 7.4 7.54 7.65 7.45 7.65 7.56 7.66 7.47 7.42 7.6 7.6 7.56 7.45 9 7.67 7.5 7.55 7.5 7.45 7.6 7.45 7.5 7.5 7.5 7.57 7.63 7.6 7.54 7.36 7.5 7.55 7.58 7.57 7.63 7.45 7.68 7.5 7.55 10 7.47 7.57 7.56 7.6 7.6 7.65 7.44 7.56 7.56 7.45 7.56 7.45 7.5 7.45 7.56 7.65 7.5 7.64 7.61 7.44 7.57 7.65 7.6 7.7 11 7.68 7.5 7.56 7.65 7.5 7.65 7.45 7.56 7.6 7.5 7.4 7.57 7.54 7.6 7.4 7.56 7.45 7.57 7.41 7.46 7.55 7.56 7.56 7.5 12 7.6 7.6 7.56 7.43 7.58 7.53 7.42 7.46 7.54 7.62 7.65 7.7 7.44 7.46 7.46 7.42 7.55 7.65 7.55 7.53 7.45 7.55 7.6 7.47 13 7.56 7.5 7.75 7.57 7.65 7.58 7.7 7.56 7.56 7.62 7.45 7.67 7.5 7.45 7.63 7.6 7.56 7.55 7.65 7.53 7.56 7.4 7.5 7.6 2418 19 20 21 22 2312 13 14 15 16 176 7 8 9 10 11unit no batch no 1 2 3 4 5 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 171 table 4: the mean and the standard deviation for each dimension st andard deviat ion mean st andard deviat ion mean st andard deviat ion mean 0.0610 7.5642 0.1463 11.5004 24.0129 0.2573 0.0926 7.5579 0.1793 11.4483 24.0088 0.2803 0.0827 7.5504 0.1521 11.5246 24.0792 0.2416 0.0671 7.5863 0.1605 11.4679 24.0942 0.1597 0.0941 7.5383 0.1522 11.3975 23.9538 0.1589 0.1166 7.5179 0.1607 11.4775 23.9888 0.1201 0.1062 7.5438 0.1370 11.5292 24.0259 0.1992 0.0829 7.5496 0.1690 11.4233 23.9921 0.1411 0.0756 7.5388 0.1429 11.3967 23.8613 0.1942 0.0774 7.5558 0.1522 11.3471 24.0050 0.1850 0.0776 7.5325 0.1285 11.4167 24.0450 0.1322 0.0812 7.5342 0.1718 11.4054 24.0113 0.1606 0.0821 7.5708 0.1702 11.3525 24.0142 0.1615 average =0.084396 average =7.549263 average =0.155592 average =11.43747 average =24.00709 average =0.183968 t hickness widt h lengt h al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 172 a: the mean chart b: the standard deviation chart figure (1): control chart for the brick length a: the mean chart b: the standard deviation chart 23.8 23.85 23.9 23.95 24 24.05 24.1 24.15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 t h e m e a n patch number l.c.l = 23.8907 u.c.l = 24.1232 ̿= 24.007 0 0.05 0.1 0.15 0.2 0.25 0.3 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 t h e s ta n d a rd d e v a ti o n patch number l.c.l =0.10210 u.c.l = 0.26583 σ̅=0.183968 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 173 a: the mean chart b: the standard deviation chart figure (2): control chart for the brick width a: the mean chart b: the standard deviation chart 11.3 11.35 11.4 11.45 11.5 11.55 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 t h e m e a n patch number l.c.l = 11.3391 u.c.l = 11.5358 ̿= 11.43747 0 0.05 0.1 0.15 0.2 0.25 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 t h e s ta n d a rd d e v ia ti o n patch number l.c.l =0.086496 u.c.l = 0.22483 σ̅=0.155592 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 174 a: the mean chart b: the standard deviation chart figure (3): control chart for the brick thickness a: the mean chart b: the standard deviation chart 7.48 7.5 7.52 7.54 7.56 7.58 7.6 7.62 7.64 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 t h e m e a n patch number l.c.l = 7.4957 u.c.l = 7.6022 ̿= 7.495 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 t h e s ta n d a rd d e v ia ti o n patch number l.c.l =0.04678 u.c.l = 0.12181 σ̅=0.0853 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 175 amethod of width test bmethod of thickness test figure (4): method of tests amethod of width test bmethod of thickness test microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 58 design of multi-layer neural networks for butterworth filter optimization assist. prof. dr. hanan a. r. akkar department of electrical & electronic engineering university of technology e-mail: hnn_aaa@yahoo.com abstract in this paper a proposed design of five multi-layer feed-forward artificial neural networks (anns) is presented for optimized butterworth filter. the first and second network perform butterworth ideal low pass filter (lpf) and typical lpf. the third ann performs band pass filter (bpf). the fourth network perform multi–bpf which consists of two layers, the first layer consists of six tansig neurons and the second layer consists of one purline neuron, and the fifth feed-forward network is designed to perform the high pass filter (hpf) which consists of three layers, the first layer consists of three tansig neurons, the second layer consists of three tansig neurons and the third layer consists of one purline neuron. back-propagation training algorithm is used to train the proposed networks with mean square error (mse) equals 10-10. simulation and test programs are implemented by using matlab. key word: artificial neural networks, digital signal processing, filters. لمرشحات البترورثمثاليتصميم الشبكات العصبية متعددة الطبقات لتمثيل حنان عبد الرضا عكار . د.م.أ ية وااللكترونيةقسم الهندسة الكهربائ/الجامعة التكنولوجية العراق/بغداد :الملخص الشبكتان العصبيتان حيث تنفذ.مرشحات البترورثلتمثيل مثالي لشبكات عصبية متعددة الطبقات خمس تم في هذا البحث تصميم أما . ح الترددات ألحزمي مرش ذي تنففتقوم ب الشبكة العصبية الثالثة أما . األولى و الثانية مرشح الترددات الواطئة المثالي والعملي ا , التي تنفذ مرشح الترددات ألحزمي المتعدد فتتكون من طبقتان , الشبكة العصبية الرابعة حيث تحتوي الطبقة األولى على ست خالي ي تي تنفذ مرشح الترددات العال ال خامسة الالشبكة العصبية وأخيرا . عصبية و تحتوي الطبقة الثانية على خلية عصبية واحدة فقط ا أم .فتتكون من ثالث طبقات حيث تحتوي الطبقة األولى على ثالث خاليا عصبية و تحتوي الطبقة الثانية على ثالث خاليا عصبية الخوارزمية ذات االنتشار العكسي في تدريب الشبكات العصبية تم استخدام . الطبقة الثالثة فتحتوي على خلية عصبية واحدة فقط .matlabاختبارها باستخدام الشبكات و تم تدريب. −1010ل التربيعي للخطأ بحدودحيث تم الحصول على المعد al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 59 introduction ann has been studied for many years in the hope of achieving human like performance in the field of speech and image recognition (stuart, 2007) . in the case of artificial net, the neuron is a node or processing element, which processes weighted inputs and produces outputs which might be used as inputs to other nodes (sivanandam, 2006). digital filters are widely used in processing digital signals of many diverse applications, including speech processing and data communications, image and video processing, sonar, radar, seismic and oil exploration and consumer electronics (madisettf, 1999). the design and realization of digital filters involve a blend of theory, applications and technologies. for most applications, it is desirable to design frequency selective filters which alter or pass unchanged different frequency components (haykin, 1999). in this paper, a proposed feed-forward ann are designed to optimized common ideal & typical digital filter types (low pass, band pass, high pass and multi-band pass) with sharp cut-off edge that cannot be implemented directly. they must be approximated with realization system the sharp cut-off edges need to be replaced with transition bands in which the designed would change smoothly in going from one band to the other. butterworth polynomial filter characteristics the butterworth filter provides the best taylor series approximation to the ideal lpf response at analog frequencies (0 and ∞ ) for any order n. the butterworth polynomials are polynomials of order n whose magnitude is given by (stein, 2000): 1 2 n aa nb ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ +=⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ω ω ω ω (1) where ω is 2πf, ωa is 2πf0 and f0 is a resonant frequency. lpf is formed by taking the reciprocal of these polynomials (kara, 2001). 1 1 2n a vo v a a ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ + = ω ω (2) gain.frequency resonant is andfilter ofgain theis where vov aa as n increases, vov aa becomes closer to one for aω〈ω , and vov aa falls off more sharply for aω〉ω .when aω=ω , 2/1=vov aa regardless of n. back-propagation training algorithm in this section a trainable layered neural networks employing the input data is presented. in the case of layered network training, the error can be propagated into hidden layers so that the output error information passes back-ward. this mechanism of back ward error transmission is used to modify the synaptic weights of internal and input layers. the back-propagation algorithm is used throughout this paper for supervised training of multilayer ffnn (kabir, 2005). al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 60 the back propagation designed to minimize the mean square error (mse) between the actual output of a multi-layer ffnn and the desired output. the following steps give summery of back-propagation algorithm( hsu, 2005): step 1: chosen e , 0 max>η , where weights w and v are initialized at small random values: w is (k x j) and v is (j x i). step 2: training step starts here, input is presented and layers outputs computed [f(net)]. 1,2,...jjfor ),xv(fy tjj =← where jv is the j'th row of v weights, and 1,2,...kkfor ),yw(fo t kk =← where kw is the k'th row of w weights. step 3: error value is computed: 1,2,...kkfor ,e)od( 2 1 e 2kk =+−← step 4: error signal vectors oδ and yδ of both layers are compute. vector oδ is (kx1), and yδ is (jx1). the error signal terms of the output layer in this step are: k 2,... 1,kfor ),o1)(od( 2 1 2 kkok =−−=δ the error signal terms of the hidden layer in this step are: ∑ = δ−=δ k 1k kjok 2 jyj w)y1(2 1 for j=1, 2… j. step5: output layer weights are adjusted: jokkjkj yww ηδ+← , for k=1, 2… k and j=1, 2… j. step 6: hidden layer weights are adjusted: iyjjiji xvv ηδ+← for j=1,2,…j and i=1,2,.. i. step 7: repeat by going to step 2. step 8: the training cycle is completed. for e<emax terminate the training session. if e>emax, then e ← 0, and initiate the new training cycle by going to step 2. description and computer simulation results the feed-forward back-propagation neural network which optimized the ideal lpf and typical polynomial lpf is shown in figure (1). the network is simulated using matlab and its output is plotted against the target as shown in figure (2), where cut frequency is 0.1 rad/sec. the weights transpose vector between inputs and first hidden layer are: v= [-1.6970 1.6970 -1.6970 -1.7017 -0.5252 30.9583] t the weights of bias(b) are: [-1.6970 1.6970 -1.6970 -1.7017 -0.5252 30.9583 ]. 1 )exp(1 2 )( − −+ = net netf λ al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 61 [ ]tw 3.17.05.02.19.02 −−= the performance training is measured according to the mean square errors mse, which equals to 1010− and learning parameter used is (1). the network is trained for (165) epochs with time of (10.094) sec, as shown in figure (3). for typical lpf the simulated ffnn is shown in figure (4) at cut-off frequency of (1.5) rad/sec.the network is trained for (1109) epochs to reach the performance goal which is ( 1010− ) with elapsed time equals (21.844) sec as shown in figure (5). other ffnn is designed to perform the ideal bpf, it consists of three layers, the first layer consists of six tansig neurons, the second consists of four tansig neurons and third layer consists of one purline neuron, as shown in figure (6). the output simulation result of the ffnn for bpf network is shown in figure (7). the adaptation is done with trains, which updates weights with specified learning function. the network is trained for (285) epochs with elapsed time equals (30.39) sec, as shown in figure (8). a proposed ffnn design of multi-band pass filter is shown in figure (9). the network consists of two layers. the first layer consists of six tansig neurons and the second layer consists of one purline neuron. the output of the simulated network is shown in figure (10). the mse ( 1010− ) of the network with (303) epochs and elapsed time equals to (14.56) sec is shown in figure (11). the last proposed design ffnn of hpf is shown in figure (12). the network consists of three layers. the first layer consists of three tansig neurons, the second layer consists of three tansig neurons, and the third layer consists of one purline neuron. the output of the simulated network is shown in figure (13). the mse ( 1010− ) of the simulated network with (303) epochs and elapsed time equals to (14.56) sec. is shown in figure (14). the following table illustrates the structure of ffnn for ideal lpf, typical lpf, ideal bpf, multi-band pf and ideal hpf with mse, no. of epochs, elapsed time and cut-off frequency for each network. the cut-off frequency illustrated in table (1) is corresponding to the location of a sharp edge of the output response of the filter as shown in figures (2, 4, 7, 10, and 13). conclusions in this paper, five feed-forward neural networks are proposed for butterworth filter optimization. these networks learn the basic analog prototype for different types of classical butterworth filter and summarize major characteristics. the created networks are trained using back-propagation algorithm that minimizes the mse between the actual output and desired output). the use of multi-layer feed forward neural networks (mffnn) with butterworth filter shows fast response for producing the estimated output signals. the estimated results are near to the actual values according to the value of mean square error (mse) based on the use of backpropagation training algorithm. this simplifies the development with better performance and fast computations of such type of applications. these proposed ffnn are very efficient and fast because of very low mse (10-10) is achieved, which gives high learning to the network to response for any selected frequency. ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ −−−−− −−− −− −−−− −−−− = 4.14.04.08.02.12.0 6.07.08.17.05.02.1 3.02.34.02.08.04.1 8.21.26.12.12.07.1 1.03.46.05.05.02.1 1w al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 62 references haykin, s., (1999) " signal and systems", john willy & sons, inc. hsu, d., (2005) " competitive learning with floating gate circuits ", ieee on circuits and systems. kabir, a.,(2005) " implementation of multi-layer neural network on fpga", college of technology indiana state university, march. karu, z. z, (2001).," signals and systems made ridiculously simple", zizi press, cambridge ma. madisettf, v. k, (1999), "digital signal processing handbook", chapman & hall / crc press llc. sivanandam, s. n, (2006)," introduction to ann's", vikas publishing house pvt ltd. stein, j.y, (2000) " digital signal processing a computer science perspective", widely interscience publication john wiley & sons, inc. stuart, r., (2007) " artificial intelligence: a modern approach", 3rd edition, prentice hall. table (1) simulation results of the proposed design. type of filter ffnn layers mse no. of epochs elapsed time sec. cut-off frequency rad/sec ideal lpf 6-5-1 1010− 165 10.094 0.1 typical lpf 6-5-1 1010− 1109 21.84 1.5 ideal bpf 6-4-1 1010− 285 30.39 0.3-0.8 multi-band pf 6-1 1010− 303 14.56 0.1-0.4 0.5-0.8 ideal hpf 3-3-1 1010− 3045 47.2 0.1 figure (1) the first and second ffnn for ideal and typical lpf. w1 bias x input layer 5 w2 v 66 1 hidden layers 1 1 5 output layer al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 63 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 frequency(rad/sec) m ag ni tu de (d b) data 1 shape-preserving data 2 0 20 40 60 80 100 120 140 160 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 165 epochs t ra in in gb lu e g oa l-b la ck performance is 9.78591e-011, goal is 1e-010 figure (2) the output of ideal lpf ffnn. figure (3) the mse of ideal lpf fnnn. 0 1 2 3 4 5 6 7 8 9 10 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 frequency(rad/sec) m ag ni tu de (d b) shape-preserving interpolant data 1 shape-preserving data 2 0 200 400 600 800 1000 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 1109 epochs t ra in in gb lu e g oa l-b la ck performance is 9.90498e-011, goal is 1e-010 figure (4) the output of typical lpf ffnn. figure (5) the mse of the typical lpf ffnn. figure (6) the ffnn for bpf . w1 b x input layer 4 w2 v 66 1 hidden layers 1 1 5 output layer al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 64 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 frequency(rad/sec) m ag ni tu de (d b) 0 50 100 150 200 250 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 285 epochs t ra in in gb lu e g oa l-b la ck performance is 3.29975e-011, goal is 1e-010 figure (7) the output of bpf ffnn. figure (8) the mse of bpf ffnn. figure (9) the ffnn of multi-band pf. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 frequency(rad/sec) m ag ni tu de (d b) data 1 shape-preserving data 2 0 50 100 150 200 250 300 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 303 epochs t ra in in gb lu e g oa l-b la ck performance is 3.987e-011, goal is 1e-010 figure (10) the output of multi-band pf ffnn. figure (11) the mse of multi-band pf ffnn w1 b x input layer v 66 1 hidden layers 1 output layer al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 65 figure (12) the ffnn for hpf. 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 frequency(rad/sec) m ag ni tu de (d b) 0 500 1000 1500 2000 2500 3000 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 3045 epochs t ra in in gb lu e g oa l-b la ck performance is 9.99921e-011, goal is 1e-010 figure (13) the output of hpf ffnn. figure (14) the mse of hpf ffnn. w1 b x input layer 3 w2 v 63 1 hidden layers 1 1 5 output layer al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 225 utilizing fuzzy recognition in hopfield neural network in relatively high corruption signal transmission ismael khaleel murad assistant lecturer in ministry of higher education and scientific research, office reconstruction and projects / reconstruction of universities department, iraq e-mail: ismael_eng@yahoo.com received 9 april 2013 accepted 24 march 2014 abstract this paper studies the utilization of fuzzy logic on pattern recognition sender after analyzing unknown pattern converged from associative. in order to specify the original patterns stored in memory. results indicated that the addition of fuzzy stage to hopfielf net to identify the unknown pattern called (frs) was succeeded in differentiating and identifying unknown patterns were produced by “hopfield neural network associative memory “(hnmar) despite of the increasing in signal corruption to relatively high levels. it was demonstrated the possibility of rising the level of performance of memory type “hopfield” where the signal corruption is at relatively higher percentage. key words: fuzzy logic, linear associative memory, recurrent neural network, hopfield network, corruption, bipolar transmission. استخدام المنطق الضبابي في تحديد األشكال التي ال يتم فيها التطابق عند تقارب شبكة الخاليا في ظل تشوه عالي باإلشارة المرسلة نسبيا " هوبفيلد" العصبية نوع ذاكرة االقتران خالصةال مرحلة اإلخراج لشبكة الخاليا العصبية نوع ذاكرة االقتران الخطي لغرض فيالمنطق الضبابي استخدامفي هذا البحث يتم دراسة تحديد الشكل المستلم عندما تفشل الشبكة في إعادة تشكيل الشكل المرسل األصلي المخزون ضمن الشبكة مع عدد آخر من األشكال من شبكة ذاكرة االقتران وتقوم بإعطاء نسبة احتمالية لربط الرمز حيث تعمل المرحلة المضببة على تحليل الشكل الغريب المنتج , الغريب نسبتا لكل رمز من األشكال المخزونة في الشبكة تبعا لقوانين مضببة يتم تصميمها باالعتماد على الرموز واألشكال المخزونة، شكل الغريب المرسل وتقريبه إلى إحدى األشكال وقد ثبت من خالل النتائج نجاح المرحلة المضببة في معرفة وتحديد الرمز أو ال المخزونة داخل الشبكة وبشكل صحيح بالرغم من ارتفاع نسبة الضوضاء إلى اإلشارة المرسلة نسبيا. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 226 nomenclature cl: column index number ep: unknown pattern that produced at the output of hopfield network after specific number of iteration when it received corrupted pattern with high percentage of noise n number of the bits frs: the addition fuzzy stage that added to the hopfield net to identify the unknown pattern mf fuzzy member ship relation hd: humming distance hnram hopfield network recurrent associative memory n number of the neurons used in the network p number of the stored patterns in the study case r: the row index number in the patter t fuzzy value of the total number of positive ones in the pattern w weights connection matrix. introduction there has been many studies on so-called hopfield neural network and its variants [1],[2]. the binary hopfield network consists of n mcculloch-pitts neurons[3] t in which have two states : firing and quiescent, each neuron receives signals from its neighboring neurons and the signals are transmitted through synaptic weights, the neurons will be fired either if total input exceeds a threshold or remains quiescent otherwise [4]. a hopfield network can be used as a content addressable memory (cam). after asset of memory patterns are learned by the network, a presentation of a noisy in put causes the network to recall a memorized pattern in successful retrieval. time independent sequences of spatial patterns [5],[6],[7] can also be stored and retrieved with hopfield network. hopfield neural network is a form of recurrent artificial neural network. hopfield nets serve as content –addressable memory system with binary threshold nodes [8]. they are guaranteed to converge to local minimum, but amiss convergence to a false pattern rather than the stored pattern (expected local minimum) might be occurred. furthermore, hopfield networks provide a model for understanding human memory [9,10]. hopfield network is a suitable model for the associative memory of nervous system has a certain degree of vulnerability to noise and interference between stored patterns. the network fails to converge to a stored pattern when the initial state is deviated from the stored pattern by a certain degree of noise [11]. the corrupted initial state evolves to one of spurious patterns which are unintended stable state. the spurious patterns are a result of correlation between different stored patterns so it is questionable whether there is a relation between stored patterns and the noise effect. it is investigated how the noise tolerance changes when the number of stored patterns increases. it was demonstrated that the noise tolerance becomes poor. the percentage of correct convergence is highly decreased with increasing the percentage of corruption with fixed values of both hd and p, so that correct convergence rate drops about linearly with the amount of corruption on the key vector [12]. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 227 therefore, it can be said that there is a tradeoff between the storage capacity and the noise tolerance in the hopfield network. seek how this tradeoff can be improved, and find that the orthogonally of stored patterns will guarantee the improvement [13,14] simulation of the situation a case investigated in this work different conditions of corruptions to converge to one of four stored prototype vectors represent the letters l,h,o,c as shown in figure (1).the number of the stored patterns and hamming distance will be will be constant. each litter is represented by 25 bipolar binary bits(+1.-1), and then the (frs) has been design and implemented and then added in cascade with the (hnram) in order to recognize the output pattern where the (hnram) fails to converge to any of the stored patterns. construction of traditional (hnram) the proposed net consists of 25 bipolar threshold neurons since there is only one layer hopfield recurrent net having number of neurons equal to a number of bits represents each stored pattern, the capacity of storage “p” for such net is given by p ≤ 0.14×25 , p ≤ 3.75 it is evidenced that the use this net to store four patterns stated before is slightly acceptable, the network contain 625 connection matrix (w).the network diagram is shown in figure (2). investigation test -1 in this test the pattern l was transmitted under 24% of corruption the received corrupted pattern ̃ as illustrated in (fig 3-2) then fed to (hnram), where ̃ =[-1+1-1-1+1-1+1-1-1-1-1-1-1+1+1+1+1-1-1-1-1+1+1-1+1], ………………………. (1) after two iterations the (hnram) successfully give correct convergence to l stored pattern as shown in (fig 3-3). pattern l is then re-transmitted but with higher percentage of corruption up to 36% as shown in (fig 4-2) where, ̃= [+1+1-1-1+1-1+1+1-1-1-1-1-1+1+1+1+1-1+1-1-1+1+1-1+1]. ……………………………… (2) when the corrupted pattern was presented at the input of (hnram) and after six iterations the net either it fails to converge the correct stored l pattern or the other three stored patterns it is attributed to high percentage of corruption. instead of correct convergence the (hnram) produced at the output unknown pattern “ep” (fig 4-3), and this pattern cannot be related to any one of the stored patterns yet, so that it is un useful where, ep=[-1+1-1-1-1-1+1+1+1-1-1+1-1-1-1-1+1+1+1-1-1+1+1+1-1]. ………………………………..(3) al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 228 investigation test-2 the (hnram) in (fig-2) is again tested but with h pattern. in the same manner, (fig 5-1) shows the uncorrupted pattern whereas fig (5-2) presents the corrupted pattern ̃ with percentage of corruption of 20%, ̃= [+1-1+1-1+1-1-1-1-1-1+1+1-1+1+1+1-1-1-1+1+1-1+1-1+1] ……………………………….(4) (hnram) was successfully recover the original stored h pattern shown in (fig 5-3) after 3 iterations on the other hand, the same h pattern transmitted under higher percentage of corruption approach 32% as given in (fig 6-2) and presenting the corrupted pattern ̃ at input of the net, (hnram) failed to recover the stored h pattern or another stored one. however, after 6 iterations it converges to un known pattern (ep) shown in (fig 6-3). ep=[+1-1+1+1+1+1-1-1-1+1+1-1+1+1+1+1-1-1-1+1+1-1-1-1+1]. …………………………….(5) fuzzy recognition solution the (ep) “unknown” recovered patterns given in test-1 and test-2 produced by the (hnram) shown in fig (5-3) and fig (6-3) when the transmitted patterns were corrupted with high degree of corruption 36% and 32% respectively. it is demonstrated that they cannot be related to any stored pattern or to be recognized. the objective of this work is to find a way that can make useful of these unknown patterns and recognize them by adding a fuzzy recognition stage (frs) at the output of the (hnram) in order to reprocess these patterns and relate each one of them to the original stored pattern and finally make a correct recognition instead of correct convergence which (hnram) couldn’t achieve. the (frs) process mainly depends on the construction of the unknown pattern as it analyze the pattern into 11 element “inputs to the (frs) system. these elements represent the total number of positive ones in hole pattern ”the first input” and in each row “inputs 2,3,4,5,6” and in each column “inputs 7,8,9,10,11”.the number of the outputs depends on the number of the stored patterns. in this case study four types are used “mamdani” fuzzy type and the centroid method will use to defuzzyfy output fuzzy values. realizing the inputs for the (frs) the first input “input-t” represents the fuzz value of the total number of positive ones in hole pattern, from (fig 1) total crisp number of positive ones in each stored pattern is given by “l=8, h=13, c=13, o=16” so that the maximum and minimum limits are is given by: 8≤ total crisp number of positive ones in hole pattern≤16 depending on that and with criteria by “4”, fig (7) shows the three proposed gaussian fuzzy linguistic values to represent “input-t” given by 4≤t1≤12 with crisp number=8, 9≤t2≤17 with crisp number=13, 12≤t3≤20 with crisp number=16. inputs 2,3,…..,6 represents the fuzzy value of total positive ones contained in each row “r1,r2,……,r5” in the pattern respectively .it is evidenced that in this work that each stored pattern consists of 5 rows and each row consists of 5 bits so that 0≤ crisp no. of total positive ones in the row “r”≤ 5 it is al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 229 suggested that six gaussian fuzzy linguistic memberships”mf1,….,mf6” to represent rows inputs”r1,r2,r3,r4,r5”, (fig 8) shows them for row1 and it is the same for other rows. where: 0≤mf1≤2 with crisp number= 0, 0≤mf2≤3 with crisp number= 1, 0≤mf3≤4 with crisp number= 2, 1≤mf4≤5 with crisp number= 3, 2≤mf5≤5 with crisp number= 4, 3≤mf6≤5 with crisp number= 5, in the same manner inputs “7,8,…,11” for the (frs) represents the fuzzy value of total number of positive ones in each column, here the patterns consists of 5 columns and each one has 5 bits so that : 0≤ crisp no. of total positive ones in the column “cl”≤ 5 and the same memberships shown in (fig 8) used before to represent rows will be used to represent the columns inputs ”cl1,cl2,cl3,cl4,cl5”. realizing the outputs for the (frs) since having four stored patterns and as it was aforementioned the (frs) has four outputs, one for each stored pattern and it determines how much the stored pattern responds in fuzzy value according to fuzzy factors presented at the inputs of the (frs) as it was given in fig (3-1). the fuzzy value produced by each output will measure the similarity between this output “one of the stored pattern” and the analyzed factors of the unknown pattern that presents at the inputs. fig (9) states three fuzzy linguistic memberships to represent the fuzzy value degree of priority relation for each output “l, h, c, and o” given by: 0.55≤ good ≤1.0 with crisp degree =1, 0≤ medium ≤1.0 with crisp degree =0.5, 0≤ poor ≤0.45 with crisp degree =0, the (frs) is completed now and fig (10) shows general block diagram. design fuzzy rules in (frs) the outputs responds to the input according to a group of fuzzy conditional rules, these rules in somehow govern the degree of effectiveness that appears in each output with respect to the input factors, and hence they decide which output has the strongest priority relation with the input pattern, number of rules depends on the degree of accuracy needed in the output and the amount of deference between output in this work there will be four rules each pattern at the output has its own rule, which will be sufficient to make a correct recognition in case study. the proposed fuzzy linguistic memberships must be examined and the relation between them and the stored patterns must be studied in order to design these rules. on the one hand, table 1” states the relation between fuzzy linguistic memberships that represents the total number of positive ones in hole pattern “input t” and the storied patterns that represents the four outputs. on the other hand, table (2) states the relation between fuzzy linguistic memberships that represents the total fuzzy number of positive ones in each row and column “inputs 2,3,………,11” and the four output stored patterns. from (table 1) it is significant to observe that when input t takes a fuzzy value within linguistic membership t1, there is no pattern at the output can take on except pattern “l”, while in the linguistic membership t2 all patterns at the output can be energized except pattern “l” but both “c”and “h” has the highest effectiveness because total number of positive ones in these patterns is located at crisp number of t2 =“13” , in t3 the same as in t2 but this time pattern “o” has the highest effectiveness due to same reason stated before . in table 2 it can be seen that when sum of positive ones of row1 “input2” for “ frs” is within fuzzy linguistic membership mf1, only “l and h” can take on in the output because r1 in these patterns is bounded within mf1, the same thing is happen when r1 is within mf2 but pattern l this time has the highest effectiveness since that sum of positive ones in r1 for pattern l is equal to “1” al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 230 and that is located at the crisp number of mf2, when r1 goes mf3, again only l and h patterns can be energized because o and c patterns have sum of positive ones not bounded within mf3, h pattern now has the highest effectiveness since that sum of positive ones in r1 for pattern h is 2 and it is equal to the crisp value in mf3, in mf4 all patterns can be taken on the consideration but no one of them can take priority. as r1 goes mf5 pattern l cannot be effected in the output because of the number of positive ones for r1 in this patter is 1 and it is unbounded within mf5, no pattern at the output has a priority, as r1 extended to mf6 the same patterns still affected but with priority to o and c patterns comes from that sum of positive ones in r1 for these patterns is 5 and it located at the crisp of mf6. as seen before each row and column in all patterns has priority in one of the fuzzy membership in table2 and each pattern has apriority in fuzzy membership in table1, these priorities “+” will help us to design the fuzzy rules, so to design the “ rule of l pattern ” that make l pattern is the winner at the output all options that satisfies priority “high effectiveness” for l pattern must be taken in account, the options that colored with blue in tables 1 and 2 satisfies all possible priorities for l pattern given by: “if input t is t1 and r1 is mf2 and r2 is mf2 and r3 is mf2 and r4 is mf2 and r5 is mf5 and cl1 is mf1 and cl2 is mf6 and cl3 is mf2 and cl4 is mf2 and cl5 is mf2 then pattern “l” is good and pattern “h” is poor and pattern “o” is poor and pattern “c” is poor” the degree of l pattern at the output depends on how many the input factors for the presented unknown pattern satisfies the conditions given in l pattern rule stated before. in the same way it can be design the other three rules depending on the rest priorities in the tables as follow: “rule of h pattern” “if input t is t2 and r1 is mf3 and r2 is mf3 and r3 is mf6 and r4 is mf3 and r5 is mf3 and cl1 is mf6 and cl2 is mf2 and cl3 is mf2 and cl4 is mf2 and cl5 is mf6 then pattern “h” is good and pattern “l” is poor and pattern “o” is poor and pattern “c” is poor” “rule of c pattern” “if input t is t2 and r1 is mf6 and r2 is mf2 and r3 is mf2 and r4 is mf2 and r5 is mf6 and cl1 is mf6 and cl2 is mf3 and cl3 is mf3 and cl4 is mf3 and cl5 is mf3 then pattern “c” is good and pattern “h” is poor and pattern “o” is poor and pattern “l” is poor” “rule of o pattern” “if input t is t3 and r1 is mf6 and r2 is mf3 and r3 is mf3 and r4 is mf3 and r5 is mf6 and cl1 is mf6 and cl2 is mf3 and cl3 is mf3 and cl4 is mf3 and cl5 is mf6 then pattern “o” is good and pattern “h” is poor and pattern “c” is poor and pattern “l” is poor” testing and evaluation in the test of the performance of “ frs”, both unknown patterns produced from (hnram) as it is illustrated in (fig 4-3) and (fig 6-3) which will be examined with the proposed “ frs” in order to recognize them and then detect the original stored pattern that was meant by the transmission in each case. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 231 recognizing ep pattern given in test-1 the unknown pattern given after convergence of (hnram) shown in (fig4-3) can be analyzed into factors t =11, r1=1, r2=3, r3=1, r4=3, r5=3, cl1=0, cl2=5, cl3=3, cl4=3, cl5=0. presenting these inputs to “frs” will produce results and priorities shown in (fig 11) and (fig 12-a), it is demonstrated that pattern” l” has the highest priority (75%), which means the original transmitted pattern was “l”, and that is a correct truth . recognizing ep pattern given in test-2 ep pattern is given in fig (6-3) to discover the original transmitted pattern. the factors of the pattern must be presented to “ frs”, t =14, r1=4, r2=2, r3=4, r4=2, r5=2, cl1=5, cl2=0, cl3=2, cl4=2, cl5=5. fig 13 and fig 12-b shows the results that state h pattern has the highest effectiveness priority (75%), means that original transmitted pattern was “h” and again the “ frs” succeeded to recognize the unknown recovered pattern. conclusions it was concluded that hopfield associative memory failed to recover the correct transmitted pattern when the transmission done under high percentage of corruption, however, adding fuzzy recognizing stage is possible to recognize the unknown pattern produced by (hnram), hence it improves the performance of (hnram) when the percentage of corruption about (32%-36%) by using “frs”. consequently using such system will be more efficient in using with larger (hnram) that deals with larger number of stored patterns and larger number of bits that patterns consists of due to high number of uncovered patterns produced in such cases, so that using “ frs” lead to restore large number of distorted patterns. future studies recommendation for future works based on the investigations carried in this study can be drawn below 1using more fuzzy rules in “ frs” and larger number of linguistic memberships, make it possible to increase the accuracy of performance and recognition given by fuzzy system, and lead to recognize patterns with larger percentage of corruption with higher accuracy. 2in work“ frs”, was succeeded in recognizing the unknown pattern with high corruption, but with modifications it can be study the possibility of “ frs” to help (hnram) recover the original transmitted pattern and not only recognize it in such conditions of transmission al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 232 references [1] s. abe, “global convergence and suppression of spurious states of the hopfield neural networks,” ieee trans. circuits syst.—ii, vol. 40, pp.246–257, apr. 1993. [2] d. j. amit, h. gutfreund, and h. sompolinsky, “statistical mechanics of neural networks near saturation,” ann. phys., vol. 173, pp. 30–67, 1987. [3] w. s. mcculloch and w. pitts, “a logical calculus of the ideas immanent in nervous activity,” math. biophys., vol. 5, pp. 115–133, 1943. [4] t. geszti, physical models of neural networks. singapore: world scientific, 1990. [5] d. kleinfeld, “sequential state generation by model neural networks,” in proc. nat. academy sci. usa, vol. 83, 1986, pp. 9469–9473. [6] h. sompolinsky and i. kanter, “temporal association in asymmetric neural networks,” phys. rev. lett., vol. 57, pp. 2861–2864, 1986. [7] l. wang, “processing spatio-temporal sequences with any static associative neural network,” ieee trans. circuit syst.—ii, vol. 5, may 1998. [8] j.j. hopfield “neural networks and physical systems with emergent collective computational abilities”, proceeding of the national academy of science of the usa, vol. 79 no. 8 pp. 2554-2558, april 1982. [9] hebb, d.o. (1949). organization of behavior. new york: wiely. [10] hertz, j., krogh, a.,&palmer, r.g.(1991). introduction to the theory of nueral computation. redwood city, ca: addison-wesley. [11] mccullough, w.s., &w.h.(1943). alogical calculus of the ideas immanent in nervous activity. bulletin of mathematical biophysics ,5, 115-133. [12] polyn, s.m., &kahana, m.j.(2008). memory search and the neural representation of context. trends in conginitive science 12,24-30. [13] rizzuto, d.s.,& kahana, m.j.(2001). an autoassocitive neural network model of paired-associate learning. neural computation, 13,2075-2092. [14] j.m zurada, “introduction to artificial neural system” jaico publishing house, 1996. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 233 table (1): relation between fuzzy linguistic memberships that represents the total number of positive ones in hole pattern “input t” and the storied patterns that represents the four outputs. table (2): relation between fuzzy linguistic memberships that represents the total fuzzy number of positive ones in each row and column “inputs 2, 3… 11” and the four output stored patterns. input t total fuzzy no. of positive ones output storied pattern t1 l+ t2 c+ , h+ , o t3 c , h , o+ input index fuzzy linguistic in p u t 2 r o w 1 in p u t 3 r o w 2 in p u t 4 r o w 3 in p u t 5 r o w 4 in p u t 6 r o w 5 in p u t 7 c o l u m n 1 in p u t 8 c o l u m n 2 in p u t 9 c o l u m n 3 in p u t 1 0 c o l u m n 4 in p u t 1 1 c o l u m n 5 mf1 l , h c , o h , l c , o l c , o h , l h l+ c , o h c , o h , l c , o h , l c , l mf2 l+,h c+,o h , l+ c+, o l+ c+, o h ,l+ h l c , o h+ c , o h+,l + c , o h+,l + c ,l+ mf3 l ,h+ c ,o+ h+, l c ,o+ l c ,o+ h+, l h+,l l c+,o + h c+,o + h , l c+,o + h , l c+, l mf4 l , h c , o c , o h , l c , o h , l c , o h , l c , o h , l c , o h c , o h , l c , o h , l c , o h , l c , o h , l mf5 h , c o o ,h o , h o , h c , o h , l+ c , o h c , o l c , o c , o c , o h mf6 h ,c+ o+ h+ c+,o + l c+,o + h+ l+ o+,h + al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 234 pattern input recovered pattern 25*25 weight matrex 25 output 25 inputs 625 connect ions 25 feedback connections figure (2): proposed hopfield associative memory neural network. figure (1): prototype patterns al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 235 1 2 3 1transmitted “l” pattern 2received corrupted “𝐿 ̃” pattern with percentage of corruption =36% 3the recovered unknown pattern (ep) at the output of the hopfield associative memory net after six iterations. figure (4): transmitting and recovering “l” prototype under corruption of 36% 1 2 3 2 3 1transmitted “l” pattern 2received corrupted “𝐿 ̃” pattern with percentage of corruption =24% 3the recovered pattern at the output of the hopfield associative memory net after two iterations. figure (3): reconstruction of transmitted prototype “l” under corruption with 24% 1transmitted “h” pattern 2received corrupted “�̃�” pattern with percentage of corruption =20% 3the recovered pattern at the output of the hopfield associative memory net after three iterations. figure (5): transmitted and recovery of “h” under corruption of 20%. 1 2 3 1transmitted “h” pattern 2received corrupted “�̃�” pattern with percentage of corruption =32% 3the unknown pattern (ep) at the output of the hopfield associative memory net after six iterations. figure (6): transmitted and recovery of “h” under corruption of 32%. 1 2 3 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 236 figure (8): gaussian fuzzy linguistic memberships to represent rows inputs”r1,r2,r3,r4,r5”. figure (9): states three fuzzy linguistic memberships to represent the fuzzy value degree of priority relation for each output “l, h, c, and o” figure (7): proposed gaussian fuzzy linguistic values to represent “input-t”. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 237 figure (10): complete fuzzy identification stage. figure (11): inputs to the “frs” and priorities produced at the output of the system in the case of (fig4-3) “l” pattern. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 238 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 a b p r o b li ty l pattern h pattern o pattern c pattern figure (12): priority of identification at the frs figure (13): inputs to the “frs” and priorities produced at the output of the system in the case of (fig6-3) “h” pattern. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 400 natural convection in a partially opened box filled with a porous medium mahmoud a. mashkour1, laith jaafer habeeb2, hafidh hassan mohammed3, hazim jassim jaber4 1,2 university of technology mechanical engineering department , 3,4university of kufa engineering college email: hazam_eng@yahoo.com abstract this research studies the heat transfer in porous medium experimentally. experimental investigation is carried out of free convection heat transfer for three dimensional in a box. the box filled with saturated porous medium, manufactured from glass with dimensions (30 × 30 × 30) cm. the porous media of plastic balls is used with homogeneous in diameter (11.7 mm). the lower wall of the box is heated by an electrical heater, while the other walls are thermally isolated. the effect of a porous medium on free convection heat transfer is studied for five values of heat fluxes (348, 576, 839, 1147, and 1384w/m2).rayleigh number is ranging between ( ) and for average nusselt number between ( ). the results showed that the temperature inside the space increases as rayleigh number increases. also, the average nusselt number increases with increase of rayleigh number for the first three values of heat flux, but it decreases after heat flux because of domination of the conduction heat transfer on convection heat transfer. also an empirical correlations were obtained in this study. keywords: free convection, porous media, enclosure. جزئياً مملوء بوسط مسامي انتقال الحرارة بالحمل الحر في تجويف مفتوح سم جابرحازم جا محمد نحافظ حس ليث جعفر حبيب محمود عطا هللا مشكور الجامعة التكنولوجية الجامعة التكنولوجية جامعة الكوفة جامعة الكوفة هندسة المكائن والمعدات كلية الهندسة كلية الهندسة هندسة المكائن والمعدات الخالصة يدرس هذا البحث انتقال الحرارة في االوساط المسامية عمليا. العمل التجريبي تم النتقال الحرارة بالحمل الحر لصندوق سم) . وان الحشوة المسامية المستخدمة تتكون 30*30*30مملوء بوسط مسامي مشبع بالهواء مصنوع من الزجاج بابعاد ( مكعب حيث يكون الجدار االسفل من الصندوق مسخن عن طريق مسخن ملم) 11.7من كرات بالستيكية متجانسة القطر بمقدار ( قيم لخمسة تأثير الوسط المسامي على انتقال الحرارة بالحمل الحر م دراسة كهربائي، بينما الجدران االخرى معزولة حرارياً ، ت al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 401 ) 5260.62الى 1537.64( لمدى رقم رايليواط/متر مربع) 348,576,839,1147,1384وهي (مختارة للفيض الحراري تزداد بزيادة رقم رايلي . كما ) وقد اظهرت النتائج العملية ان درجة الحرارة داخل الحيز61.24الى 52.44( ولمدى رقم نسلت بينت ايضا ان معدل رقم نسلت يزداد مع زيادة رقم رايلي في القيم الثالثة االولى للفيض الحراري ، لكنه يتناقص بعد القيمة ستنتاج بالحمل. وكذلك فقد تم في هذا البحث ا الرابعة للفيض الحراري وذلك بسبب سيطرة التوصيل الحراري على انتقال الحرارة عالقات ارتباطية (تجريبية). nomenclature dh hydraulic diameter m ds diameter of solid beads m g gravitational acceleration m/s2 h height of the box m the average heat transfer coefficient w/m2.oc hy the local heat transfer coefficient w/m 2.oc k permeability m2 kf thermal conductivity of the fluid w/m.k km effective thermal conductivity of the porous medium w/m.k ks thermal conductivity of the spheres (beads) w/m.k l length of the box m ms weight of spheres. kg vdis the volume of the water displaced m 3 v total box volume m 3 v solid plastic beads volume m 3 qw heat flux w/m 2 ti the local temperature oc ts the lower surface temperature oc greek symbols αm thermal diffusivity of porous medium m 2/s ε porosity ρ density kg/m3 µ dynamic viscosity of fluid kg/m.s υ kinematic viscosity m2/s subscripts f fluid (air) i local m effective s solid al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 402 y y – axis non-dimensional numbers nu the local nusselt number the average of nusselt number ra the rayleigh number 1. introduction the topic of heat transfer in porous media is one of the important field in the engineering study in nowadays. the theme of free convective heat transfer in square box filled with saturated porous media is important in many practical fields. for example, petroleum technology and mechanical and chemical engineering, civil engineering, environment engineering and the field of farming engineering. heat transfer problems through porous media have become an intensive research topic for last few decades because of their possible applications in many members of science and technology. the most important research on this topic can be reviewed as following: (prasad, and kulaki, 1984) studied numerically the two-dimensional steady natural convection in a porous rectangular cavity heated from the side for different values of (width/height) ratio and rayleigh numbers. the average nusselt number was observed to be a maximum in a restricted range of aspect ratio (width/height), depending on the rayleigh number (ra*). they established a criteria in terms of aspect ratio and (ra*) for the existence flow regimes [1]. (misirlioglu et al, 2005) investigated numerically the steady-state free convection inside a cavity made of two horizontal straight walls and two vertical bent wavy walls and filled with a fluid-saturated porous medium.the wavy walls were assumed to follow a profile of cosine curve. the horizontal walls were kept adiabatic, while the bent-wavy walls were kept isothermal at different temperatures. he concluded the heat generated in the porous medium cannot be transferred through the porous medium from the right (hot) wall to the left (cold) wall [2]. (watit and phadungsak, 2006) conducted a study on the transient natural convection flow through a fluid-saturated porous medium in a square enclosure with a convection surface condition. the cavity was insulated except the top wall was partially exposed to an outside ambient. the exposed surface allows the convective transport through the porous medium, generating a thermal stratification and flow circulations. it was found that the heat transfer coefficient, rayleigh number and darcy number greatly influenced the characteristics of flow and heat transfer mechanisms. furthermore, the flow pattern was found to have a local effect on the heat convection rate [3]. (hakan oztop, 2006) investigated numerically the natural convection heat transfer in a partially cooled and inclined rectangular enclosure filled with a saturated porous medium. one of the side walls had a constant hot temperature and one of the adjacent walls was partially cooled, while the remaining ones were adiabatic. he found that the inclination angle was the dominant parameter on the heat transfer and fluid flow as well as aspect ratio [4]. (tanmay et al, 2006) investigated numerically the natural convection flow in a square cavity filled with a porous matrix. they used darcy–forchheimer model to simulate the momentum transfer in the porous medium. they concluded that the nonuniform heating exhibits greater heat transfer rates at the center of the bottom wall than that with the uniform heating case for all rayleigh number regimes [5]. (saleh et al, 2010) investigated the unsteady natural convection in a square region filled with a fluid-saturated porous medium having non-uniform internal heating and heated laterally. the heated wall surface temperature varied sinusoidally with the time about fixed mean temperature. the opposite cold wall was maintained at a constant temperature. the top and bottom horizontal walls were kept adiabatic. the flow field was modeled with the darcy model and was numerically solved using a finite difference method. it was found that strong internal heating can generate significant maximum fluid temperatures above al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 403 the heated wall. the location of the maximum fluid temperature moved with time according to the periodically changing heated wall temperature. the augmentation of the space-averaged temperature in the cavity is strongly depended on the heating amplitude and rather insensitive to the oscillating frequency [6]. (muyassar ismaeel, 2011) investigated the natural convection heat transfer in a square porous cavity with partial cooled vertical walls. the left vertical side wall was partially heated, and the right side wall was partially cooled. depending on the positions of the hot and cold parts, nine cases were considered in his investigation. flow and heat transfer characteristics for all cases were studied for a range of rayleigh number (50≤ ra ≤ 500). he solved the governing equations numerically with the aid of the finite difference technique and gauss–siedel method. the numerical results showed that there are significant changes in the flow and temperature fields and the rate of heat transfer due to the change of the positions of hot-cold parts. also, he showed that the maximum heat transfer occurs for the lower-upper arrangement, while the minimum heat transfer occurs for the upper-lower arrangement. it was observed that the arrangements of active portions played an important role on flow, temperature fields and heat transfer [7]. 2. experimental apparatus and data reduction 2.1 test rig description the test rig is designed and manufactured to fulfill the requirements of the test program for a free convection heat transfer. the experimental apparatus consist basically of the test section, the constant heat flux heater and the measuring devices. most parts of the test rig are manufactured, and a care is take to prevent any air leakage during operation between the test rig parts connection (fig 1-a) illustrates schematic diagram of experimental apparatus, and (fig 1-b) shows the photograph of the test rig. (a) (b) figure (1): (a) schematic diagram of experimental apparatus,(b) the photograph of the test rig. squar e duct square duct voltage regulator wait meter heater test section plastic tubes al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 404 2.2 the test section the experimental model used in the present study is a square box filled with spherical plastic beads. the main dimensions of the box are; length (l=30 cm), width (w=30 cm) and height (h=30 cm) as shown in (fig. 2). all the walls of the box are constructed from a glass of thickness (6 mm). a glass wool insulation of (50 mm) thickness is applied to insulate all walls except the lower wall in order to reduce the heat loss. on the bottom wall of the square box a uniform heat flux is provided by means of electric tape heater. the partially opened opposite sides of the box are punctured with square holes (6×6) cm at the right lower and the left upper squares to the entry and exit air respectively. then, a galvanized steel mesh is cited in order to prevent the beads from going out of the box. one hole was drilled in the center of the upper wall for entry (25) thermocouples in order to measure the temperatures inside the box. the thermocouples are arranged to form a tree the distribution in order to measure the temperature at different locations according to the grid distribution. the grids are distributed horizontally and vertically in order to take into account all the temperature variation in the model, as shown in (fig. 2). the square box is filled with plastic (polypropylene) beads saturated with air. the plastic beads constant diameter is (11.7 mm) and having the physical properties as shown at [8]. the square holes are existed into two square ducts (6 cm×6 cm) with (70 cm) and (15 cm) length. they are manufactured from limpid plastic of (4 mm) thickness. the box is stand at an iron frame to prevent any air leakage from corners, silicon is used. figure (2) thermocouples distribution on grid. 3. layout and measured parameters during the experimental investigation, the main parameters measured are: 1. the surface temperature of the box. 2. the temperature distribution within the test section. 3. the heat flux (current and voltage) experiments were carried out to study the effect of influence of heat flux range, and to determine the temperature distribution in the porous media. these parameters can be summarized in (table 1). al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 405 4. experimental procedures experiments were conducted to measure the temperatures and heat fluxes. the experimental work was done in a specially designed cubic box filled with a porous medium where the thermocouples distributed in three dimensions. the general steps were followed in this experimental investigation for free convection heat transfer is given below: 1. arranging the required outlet heat flux from the heating system at the bottom of the test section is arranged manually by adjusting the supplied voltage accordance to the first value of the heat flux required which is (348w/m2). 2. waiting the steady state condition is reached about (180-270) minute. 3. recording the temperatures distribution through the porous media within the enclosure using the (25) thermocouples at (0, 0.5, 9.5, 19, 28.5, 30, 30.6) cm in the y-direction till reaching the upper surface. 4. repeating the experimental procedure step (1) to step (3) for all heat fluxes considered. 5. calculations of porous media parameters 5.1 porosity (ε) the average porosity of the porous medium is compute for each particle with constant diameter of (11.7 mm). the porosity or void fraction of a porous medium is defined by [9]: the plastic beads volume is measured by multiply the volume of one bead by the total number of the plastic spheres, which gives ε = 0.422. 5.2 density (ρ) the density of the plastic spheres is found to be (989.16 kg/m³). 5.3 permeability (k) the permeability depends on the porosity and plastic sphere diameter as given by [10 & 11]. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 406 the permeability of the plastic spheres is found to be (2.0529*10ˉ7 m²). 6. calculation of the effective thermal conductivity (km) an important property of the porous medium is the medium thermal conductivity (km). as reviewed in the previous investigations, by [8, 10, and 12], a typical mixing rule based on the volume fraction is usually being applieder. in which (kf) calculated at the average working temperature of 60˚c and its values is (28.65*10ˉ3). the parameter (ks) used in the present work is taken as given by [8]. the prediction values made by equation (4) is found to be accepted only if (kf ≈ ks ), i.e. the conductivity ratio, λ= kf / ks ≅ 1. since the conductivity ratio is less than unity, ( λ=0.1155), the better choice is by using krupiczka’s correlation according to (prasad 1989) krupiczka’s correlation based on a two dimensional heat transfer model that predicts more accurate values of (km ) [13].therefore correlation takes the form: where: n =0.28-0.757 log10 ε +0.057 log10 λ (6) thus (km) is found to be (0.08617 w/m.k). 7. the heat capacity the heat capacity of the porous medium is estimated by using the mixing rule based on the volume fraction such as: ( where: (ρ cp)m is the heat capacity of the porous medium. (ρ cp)f is the heat capacity of the air. (ρ cp)s is the heat capacity of plastic spheres. the specific heat of the solid sphere is obtained from [8], and it is equal to (cps = 1.939 kj/kg .k). the constant pressure specific heat of the air is obtained from the references according to the average working temperature of 60˚c, and it is equal to (cpf = 1.008 kj/kg .k). al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 407 8. the rayleigh number (ra): for the natural convection, rayleigh number can be defined in equation (8) as following: (β) is the thermal coefficient of volume expansion and (αm) is the thermal diffusivity where of the porous medium as given by [13].in the following relation. all the main parameters in the equation (8) are either calculated from the tables or from the previous calculations. 9. hydraulic diameter calculation the hydraulic diameter for a medium composed of uniform spherical particles requires an appropriate definition of the hydraulic diameter as follows according to [9]. where (dh) is equal to (5.695 mm). 10. calculation of heat transfer coefficient(h) the local heat transfer coefficient by free convection can be calculated as: the local nusselt number ( can be determined by: also the average of nusselt number ( ) can be calculated as: the above integration can be done by using the trapezoidal rule as follows: al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 408 sample calculation of is presented in (table 2). 11. results and discussion 11.1 temperature distributions the steady state temperature distributions along the vertical direction for different x z planes are illustrated. (figs.1.2.and3.) show the temperature distributions (y). as it is seen from (figs. 1a, b & c), the temperature distributions decreases along the y-direction indicate a linear temperature distribution pattern. upon moving upward, the heat resistant increases causing a reduction in the temperature values. (fig. 1-a) is gave similar behavior of (fig. 1-c), because (xy) planes (z = 0 cm to z = 29 cm) lies in the entrance and exit vents planes, which cause a temperature difference. however, figure (1-b) for plane (z =14.5 cm) lies in the center of the box and does not lose a lot of temperature, since the vent is far enough from this plane. so, the temperature distributions according to (x) values are logical at (x = 29 cm), the temperature will be less, because this plane is near to upper exit vent and for all cases. the above mentioned is coincident with the contour drawing for planes (x-y-t) for the behavior of temperatures at each point for each plane. the ascending and descending convective flow within the box gives the curvilinear isothermal lines in these figures. however, the isothermal contour maps still give some of asymmetry about the mid vertical line. the hot air is occupied the bottom regions, and the cold air is occupied the upper regions. also, one can conclude from (figs. 1-d, e& f) that the convective flow is stronger, making isothermal linear lines, especially at the lower corners of the plane. therefore, the isothermal lines near these corners seem to be more smoothly. 11.2 nusselt and rayleigh numbers heat transfer rates in terms of nusselt number are presented in (fig. 4). (fig. 4-a) manifests the effect of rayleigh number (ra) on the variation of the average nusselt number ( ). as seen from this figure, the average nusselt number increases with rayleigh number as the heat flux (qw) values increase until (qw3 = 839w/m2), and then the average nusselt number value decreases, because of the temperature of the air reaches almost a constant values, and so that the value of heat transfer by bead conduction is indicated a dominant element on heat transfer by convection in air. the thermal capacity for beads (cps =1939 j/kg. k) is higher than the thermal capacity of air (cpf =1008 j/kg. k), so the air reaches the thermal stability faster than the beads. nusselt number ( ) depends on the value of porous media thermal conductivity factor. so the increase in the heat flux (qw) will cause increase in porous media conductivity, this cause drop the average nusselt number ( ) value. since (fig. 4-b) shows that the nusselt number decreases along the y-axis, and it is similar in behavior to that of all heat flux (qw) values. these results may verify the physical interpretation with the results of [5], [6]. the statistical analysis (using statistica software) based on the minimum sum of square error (sse) led to the following relationship given in (table 3). al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 409 12. conclusions the following points can be concluded from the present experimental work: 1.the values of temperature and local nusselt number remain stable approximately after (y=12.5 cm), above this region it is regards as the cooling plane. 2.the temperature values in the box vary inversely with the box height and directly with the heat flux. 3.a rapid increase in the temperature values within the box is deduced as the heat flux is increased due to a strong convective flow that increases the heat transfer within the box. 4.a wavy shape of the distribution temperature is obtained along a line parallel to the horizontal xdirection. the isothermal lines become more wavier in shape as the heat flux increases. 5.the rate of free convection heat transfer increases with the rayleigh number increases at low values of heat flux applied on the heating surface. 6.the rate of free convection heat transfer is inversely proportional to the rayleigh number for high values of heat flux, because the effect of conduction heat transfers is more than the convection of heat transfer. references [1] prasad. v, and kulacki, f. a., "convective heat transfer in a rectangular porous cavity-effect of aspect ratio on flow structure and heat transfer", journal of heat transfer, vol.106, pp.158165, 1984. [2] aydin misirlioglu, a. cihat baytas, and ioan pop. , "free convection in a wavy cavity filled with a porous medium", journal of heat and mass transfer, vol. 48, pp. 1840–1850, 2005. [3] watit pakdee, and phadungsak rattanadecho., "natural convection in porous enclosure caused by partial heating or cooling", the 20th conference of mechanical engineering network of thailand, 18-20 october 2006, nakhon ratchasima, thailand . [4] hakan f. oztop., "natural convection in partially cooled and inclined porous rectangular enclosures", journal of thermal sciences, 46, pp. 149–156, 2006. [5] tanmay basak, s. roy, t. paul, and i. pop., "natural convection in a square cavity filled with a porous medium: effects of various thermal boundary conditions", heat and mass transfer, 49, pp.1430–1441, 2006. [6] h. saleh, i. hashim, and n. saeid.,"effect of time periodic boundary conditions on convective flows in a porous square enclosure with non-uniform internal heating",transp porous med, 85, pp. 885–903, 2010. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 410 [7] muyassar e. ismaeel.,"heat transfer in a square porous cavity with partial heating and cooling for opposite vertical walls", al-rafidain engineering, vol.19, 2011. [8] suhad a. h. rasheed.," mixed convection heat transfer in saturated porous media inside a circular tube", university of technology, 2006. [9] ron. draby, "chemical engineering fluid mechanics" second edition, 2001. [10] kifah hamid hilal, "fluid flow and heat transfer characteristics in a vertical tube packed bed media", university of technology, thesis, 2004. [11] pei-xue jiang , xiao-chen lu, "numerical simulation of fluid flow and convection heat transfer in sintered porous plate channels", heat and mass transfer 49 (2006) 1685–1695. [12] tahseen ahmad tahseen., "an experimental study for mixed convection through a circular tube filled with porous media and fixed horizontally and inclined", issn, pp. 1913-1844, 2011. [13] d.a. nield, a. bejan, "convection in porous media", third ed., springer, new york, 2006. table (1): parameters range of the experimental work. table (2): sample of the nusselt number calculations. table (3): specific empirical equation for free convection. atmospheric temp. (oc) heat flux (w/m2) period to reach steady state (min) 19 22 348 1384 180 360 qw (w/m2) qw1 =348 qw2 =576 qw3 =839 qw4 =1147 qw5 =1384 52.44 53.53 61.24 58.2 56.4 ra 1537.64 2446.46 3487.13 4488.86 5260.62 = c1 rac2 c1 c2 r2 28.552 0.08434 81.6 % al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 411 figure (1): temperature distribution (a, b and c) and contours (d, e and f) at (qw1 =348 w/m²). y(c ) 0 5 10 15 20 25 0 5 10 15 20 25 30 (d) x (cm) z=0 cm y(c m) 0 5 10 15 20 25 0 5 10 15 20 25 30 (e) x (cm) z=14.5 cm 0 5 10 15 20 25 0 5 10 15 20 25 30 (f) x (cm) z=29 cm y(c m) al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 412 (d) figure (2): temperature distribution (a, b and c) and contours (d, e and f) at (qw3 =839 w/m²). (e) x (cm) z=14.5 cm y(c m) 0 5 10 15 20 25 0 5 10 15 20 25 30 0 5 10 15 20 25 0 5 10 15 20 25 30 y(c m) (f) x (cm) z=29 cm 0 5 10 15 20 25 0 5 10 15 20 25 30 y(c m) (d) x (cm) z=0 cm (a) (b) (c) al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 413 figure (3): temperature distribution (a, b and c) and contours (d, e and f) at (qw3 =1384 w/m²). (d) x (cm) z=0 cm 0 5 10 15 20 25 0 5 10 15 20 25 30 y (cm ) (e) x (cm) z=14.5 cm y (cm) (f) x (cm) z=29 cm 0 5 10 15 20 25 0 5 10 15 20 25 30 y (c m) al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 414 figure (4): (a) variation of the average nusselt number with rayleigh number, (b) variation of local nusselt number with y-axis, at qw = (348, 576, 839, 1147, 1384) w/m². references al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 322 utilization of waste plastic and recycle concrete aggregate in production of hot mix asphalt basim h. al-humeidawi university lecturer, civil engineering department, college of engineering university of al-qadissiyah basim.alhumeidawi@yahoo.com received 1 september 2014 accepted 14 october 2014 abstract recycling of waste material is a recent technique aims to change the waste material into new products to reduce the pollution and detrimental effect on the environment and reduce the demand of new fresh natural sources. plastic bags and recycled concrete aggregate (rca) are samples of these waste materials can be re-used in road construction. over one million bags are used every minute worldwide, whereas, aggregate is consist of about 95% of asphalt mixture and can be obtained as rca from demolished infrastructure. this paper presents laboratory tests results of using waste plastic and rca in production of asphalt mixture. since the cement past attached to rca particles contribute to lower their density and increase the porosity, the waste plastic are used to enhance the engineering properties of asphalt mixture and consume these large amount of waste material. the results showed that waste plastic modified bitumen (wpmb) mix containing 100% rca produces higher marshall stability, higher retained stability and higher indirect tensile strength compared with conventional mix. the percents of the increase were 10% for marshall stability, 7% for marshall retained stability and 9% for higher indirect tensile key words: asphalt mix, road construction, marshall stability; waste plastic; recycled concrete aggregates; environment; waste management استخدام المخلفات البالستيكيه والركام المدور في انتاج الخلطات االسفلتيه هندسة طرق ومطارات -باسم حسن شناوة / دكتوراه هندسة مدنية الخالصة : تدوير المخلفات الى منتجات جديده لتقليل التلوث واالثار تقنيه حديثه تهدف الى اعاده اعادة استخدام المخلفات الصناعيه واالنشائيه االكياس البالستيكيه والركام المدور )المعاد استخدامه( ان السلبيه على البيئه وتقليل الطلب على المصادر الطبيعيه للمواد االنشائيه. اكثر من مليون اظهرت الدراسات السابقه ان نماذج للمخلفات الصناعيه واالنشائيه التي يمكن اعادة استخدامها في انشاء الطرق. يمكن الحصول على االسفلتيه. % من مكونات الخلطة59بينما يشكل الركام اكثر من كيس بالستيكي تستخدم كل دقيقه حول العالم mailto:basim.alhumeidawi@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 323 الركام المدور من مخلفات االبنيه والمنشاءات الكونكريتيه القديمه المهدمه. هذا البحث يعرض نتائج دراسه مختبريه العادة ر يساهم بما ان االسمنت الملتصق بالركام المدواستخدام مخلفات االكياس البالستيكيه والركام المدور في انتاج الخلطات االسفلتيه. ن خصائص الخلطة االسفلتيه الحاويه على يفي تقليل الكثافة وزيادة المساميه للركام المدور , تم استخدام المخلفات البالستيكيه لتحس اظهرت ان قوة الحالي على شكل مخلفات. نتائج البحث ههذا النوع من الركام والستهالك الكميه الكبيره من هذه االكياس والمتوفر التي تحتوي المخلفات البالستيكيه والركام االسفلتيه رشال والثبات المتبقي بعد الغمر وفحص الشد غير المباشر للخلطهثبات ما اضافة الى االسفلتيه % مقارنة مع قيمها للخلطة القياسية ممايوفر تحسن في نوعيه الخلطه01-7المدور اعلى بمعدل يتروح من .ات المذكورهتدوير كميه كبيره من المخلف اعادة 1. introduction and background the availability of different waste materials is increasing day by day and the disposal of these materials is a big problem. these wastes are increasing the concern of environmental pollution since many of these materials are non-biodegradable. plastic one of these materials, which is a very versatile material widely used in packaging of many outputs of industry. a survey has shown that 500 billion plastic bags are used worldwide every year (plastic bag pollution 2005). without thinking in a suitable way to utilized these materials in recycling industries, these wastes have occupied landfill areas and become source of pollution. several studies have been conducted to investigate the use of plastic waste in bitumen mixture of the flexible pavement (chavan 2013; gawande et al. 2012; sangita and verinder 2011; swami and jirge 2012). in addition to re-use of waste plastic can significantly reduce the disposal problem of these waste and minimize the concern of pollution, they can enhance pavement performance and reduce the cost of construction of roads. the results of previous studies showed that the using of waste plastic in asphalt mixture improve the engineering properties such as marshall stability, resistant to water (measure by retained stability) and resistant to crack propagation (indicated by indirect tensile strength of modified asphalt mixes). this approach of modification also produces better binding property for the bitumen mix and increase the road life (chavan 2013; gawande et al. 2012; sangita and verinder 2011; swami and jirge 2012). the other waste material which can be recycled to be used in road construction is the recycled concrete aggregate (rca). rca can be obtained from construction debris, where demolished concrete structures are crushed to smaller units for diverse uses. aggregate is main component of asphalts mixture, it composes about 95% of asphalt mix. the continuous use of this material is threatening the natural resources of it; especially, it is known that the flexible pavement is one of most worldwide pavement type. therefore, the recycled of this material can protect the environment, provide sustainable construction and reduce the demand on natural resources, moreover, reduce the construction cost of the road (huang et al. 2007). however, the engineering properties of rca differ from natural aggregates due to remaining cement paste on their surfaces after the recycling process. the attached cement paste contributes to lower density, increase porosity and water absorption of rca (mills-beale and you 2010; paranavithana and mohajerani 2006). other investigations showed that rca can be a good and economical alternative to fresh aggregate and can produce asphalt mixtures withstand traffic load especially in light and medium traffic (akbulut and gurer 2007; moghadas nejad et al. 2013). the current article focuses on using both the waste plastic and rca in asphalt mixture to produce asphalt mixture with higher engineering properties compare to conventional mix and consume the waste materials. this approach also reduces the construction cost of the road and minimising the consumption of natural resources. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 324 2. methodology the laboratory tests in this research consist of four aspects. these aspects involved production of four different asphalt mixes: 1standard asphalt mix with optimum bitumen content. 2waste plastic modified bitumen mix (wpmb-mix). 3asphalt mix contains 100 % recycled concrete aggregate (rca-mix). 4waste plastic modified bitumen mix contains 100 % recycled concrete aggregate (wpmb + rca). in order to obtain and evaluate these mixes the test methodology involved four steps: 1preliminary test for the component of asphalt mix and obtaining optimum bitumen content for asphalt mix. this phase involved several standard tests such as penetration test, flash point test, softening point test and the ductility test. then, six mixes with different bitumen content (4.0 %, 4.5 %, 5.0 %, 5.5 %, 6.0 % and 6.5%) were produced to select optimum bitumen content using marshall method. the optimum bitumen content was 4.85%. 2mixing of waste plastic with bitumen: generally, there are three different methods to mix the plastic with bitumen as shown below.  dry process: in this method, the waste plastic is added to hot aggregate particles to produce a plastic coated aggregate. the plastic coated aggregate is then mixed with optimum quantity of bitumen to get a wpmb mix.  wet process: this process involves melting and mixing the waste plastic with hot bitumen a round 150 0 c using a bitumen mixer to get wpmb. the modified bitumen (wpmb) is added to heated aggregate to get a wpmb mix. this process was adopted in the current research, where waste plastic bags were melted and stirred in bitumen according to above mentioned procedure. the percent of waste plastic was 8 % of the weight of the bitumen, adopted according to previous studies in literature (gawande et al. 2012; sangita and verinder 2011; swami and jirge 2012)  semi wet process: this method refers to non-completely melting of waste plastic in hot bitumen where small plastic particles are still insoluble during cooling of wpmb to ambient temperature. in this process, the waste plastic acts as modifier for the bitumen and as a coating for aggregate when it is added to aggregate to get a wpmb mix. 3obtaining of recycled concrete aggregate (rca): in this work, the rca was obtained from waste concrete testing cubes. cubes were crushed and abraded using los angles abrasion machine for 20-30 minutes to get different sizes of aggregate particles. these particles were washed and dried using electric oven for 24 hours. the resulting particles where classified according to mid-range of specification of aggregate gradation using sieve analysis for these particles. 4evaluating the four mentioned mixes using the following tests: the evaluation process for the four mixes included in this study involved conducting three tests. these tests are:  marshall stability test: the standard marshall test for mix design was carried out on the standard asphalt mix, wpmb-mix, asphalt mix contains 100 % rca and wpmb-mix contains 100 % rca. the marshall stability, flow and density were evaluated for three samples of each mix.  marshall retained stability test: this test was conducted to evaluate the pavement performance under severe conditions such as soaking of the pavement in water for long time. marshall stability tests were carried out after immersion the specimen in water at 60 0 c for 24 hours. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 325  indirect tensile strength test: this test comprises of applying compressive loading along the vertical diameter of a cylindrical specimen to produce tensile stresses cracks perpendicular to loading axis. the specimen was prepared and tested according to aashto t 283 specification. the indirect tensile strength (its) is calculated as shown in equation (1) below. 𝐼𝑇𝑆 (1) where: its = indirect tensile strength (mpa) p = applied load (n) h = average height of specimens (mm) d = average diameter of specimens (mm) fig.1 presents the whole picture of the research frame work. 3. results and discussion standard marshall test: after adopting the optimum content of bitumen, the standard marshall test was carried out on the four mixes. the marshall stability and flow were record for each type of mix as shown in fig.2 and fig.3. marshall stability refers to maximum load sustain by asphalt mix, this can be an indication for pavement distortion, rutting and shear stress. fig.2 shows the marshall stability for the four mixes. it can be observed that the marshall stability increases by about 30% and 15% for the wpmb mix and wpmb mix containing rca respectively compared with standard mix. while it decreases by about 10% for the rca mix compared with standard mix. this can be attributed to that, the using of waste plastic in asphalt mixes may lead to better blending and binding of asphalt mix also decreasing of the air voids which consequently lead to higher stability for mixes. for the rca mix, the cementation material attached with aggregate particles leads to increase the porosity, water absorption and decrease density (paranavithana and mohajerani 2006); which, consequently decreases marshall stability and increases marshall flow (see fig.4). fig.3 shows the comparison of displacement or flow of the mixes during the marshall test. the addition of waste plastic to asphalt mixture produces less flow due to better binding of mix components. fig.4 presents the densities for the four mixes, the wpmb mix shows less density compared with conventional mix due to less density of waste plastic. the reduction in density is increasing by adding the rca due to higher porosity and water absorption for rca. marshall retained stability test: this test can assesses pavement condition when it subjected to severe conditions such as soaking in water for long time. fig.5 presents the marshall retained stability results after socking in water for 24 hours at 60 0 c. fig.5 reveals generally that the marshall stability decrease for all mixes, but all values are more than 70% of marshall stability values as shown in fig.6. the marshall retained stability is higher by about 10% and 7% for the wpmb mix and wpmb containing rca mix respectively compared with marshall retained stability for the standard mix. while it is less by about 15% for the rca mix compared with standard mix. indirect tensile strength: this test is conducted to assess the tensile properties of asphalt mix which can be further linked to the cracking properties of the flexible pavement. several distresses of pavement such as low temperature cracking, fatigue and rutting are related to tensile properties of asphalt mix. a higher tensile strength leads to higher cracking resistance and higher strain prior al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 326 to failure of the pavement(tayfur et al. 2007). fig.7 presents the comparison of tensile strength for the mixes under consideration. it can be clearly seen that waste plastic improved the tensile properties of the asphalt mix; however, this improvement are slightly decrease with using of rca in bitumen mixes. the indirect tensile strength increases by 30 % and 10 % respectively for the wpmb mix and wpmb mix containing rca respectively compared with that of the standard mix. while it decreases by about 20% for the rca mix compared with standard mix. 4. summary and conclusions this paper has presented an experimental investigation for using waste plastic and rca in hot mix asphalt (hma) for road pavement. the results showed that the using of rca alone (without of waste plastic as modified) causes reduction in marshall stability and indirect tensile strength of the asphalt mix; which, consequently produces reduction in the resistance of pavement to deterioration and cracks formulation. on the other hand, the using of waste plastic in asphalt mix which has 100% rca can produce better asphalt mixture compared with conventional mix. the use of recycled material (rca and waste plastics) in the pavement of the road has helped to solve the problem of disposal of waste plastic and demolished concrete structural elements by providing better place for burying them. at the same time, a better pavement can be achieved by improving the marshall stability, strength, fatigue life and other desirable properties of asphalt mix, consequently improves the longevity and pavement performance. finally, the using of these waste materials can significantly reduces the construction cost of the roads. references [1] akbulut, h., and gurer, c., 2007. "use of aggregates produced from marble quarry waste in asphalt pavements." building and environment, 42(5), 1921-1930. [2] chavan, m. a. j., 2013. "use of plastic waste in flexible pavements." international journal of application or innovation in engineering and management, 2(4), 540-552. [3] gawande, a., zamare, g., renge, v. c., tayde, s., and bharsakale, g., 2012. "an overview on waste plastic utilization in asphalting of roads." journal of engineering research and studies, 3(2), 01-05. [4] huang, y., bird, r. n., and heidrich, o., 2007. "a review of the use of recycled solid waste materials in asphalt pavements." resources, conservation and recycling, 52(1), 58-73. [5] mills-beale, j., and you, z., 2010. "the mechanical properties of asphalt mixtures with recycled concrete aggregates." construction and building materials, 24(3), 230-235. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 327 [6] moghadas nejad, f., azarhoosh, a. r., and hamedi, g. h., 2013. "the effects of using recycled concrete on fatigue behavior of hot mix asphalt." journal of civil engineering and management, 19(sup1), s61-s68. [7] paranavithana, s., and mohajerani, a., 2006. "effects of recycled concrete aggregates on properties of asphalt concrete." resources, conservation and recycling, 48(1), 1-12. [8]plastic bag pollution, 2005. "retrieved from http://www.googobits.com/articles/1604-plasticbag-pollution.html." [9] sangita, g. r., and verinder, k., 2011. "a novel approach to improve road quality by utilizing plastic waste in road construction." journal of environmental research and development vol, 5(4), 1036-1042. [10] swami, v., and jirge, a., 2012. "use of waste plastic in construction of bituminous road." international journal of engineering science & technology, 4(5), 2351-2355. [11] tayfur, s., ozen, h., and aksoy, a., 2007. "investigation of rutting performance of asphalt mixtures containing polymer modifiers." construction and building materials, 21(2), 328337. figure1: research frame work http://www.googobits.com/articles/1604-plastic-bag-pollution.html. http://www.googobits.com/articles/1604-plastic-bag-pollution.html. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 328 figure 2: marshall stability figure 3: marshall flow 6.0 7.0 8.0 9.0 10.0 11.0 standard wpmb rca wpmb + rca m a rs h a ll s ta b il it y ( k n ) type of mix 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 standard wpmb rca wpmb + rca f lo w ( m m ) type of mix al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 329 figure 4: density of asphalt mixes figure 5: marshall retained stability 2.250 2.270 2.290 2.310 2.330 2.350 standard wpmb rca wpmb + rca d e n si ty ( g /c m 3 ) type of mix 6.0 6.5 7.0 7.5 8.0 8.5 9.0 standard wpmb rca wpmb + rca m a rs h a ll r e ta in s ta b ik it y (k n ) type of mix al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 330 figure 6: comparison of marshall retained stability values with marshall stability values figure 7: results of indirect tensile strength (its) 6.0 7.0 8.0 9.0 10.0 11.0 standard wpmb rca wpmb + rca m a rs h a ll s ta b il it y ( k n ) type of mix marshall stability marshall retained stability 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 standard wpmb rca wpmb + rca in d ir e c t te n si le s tr e n g h t (m p a ) type of mix microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 45 a wideband model for estimating the direction of arrival in the phased array antenna dr. saad saffah hassoon dr. ehab abdul-razaq husain babylon university babylon university college of eng. college of eng. elect. eng. dept. elect. eng. dept. abstract in this paper, a new wideband direction-of-arrival (doa) estimation method is proposed, related to the real time capability of doa estimator the complexity estimation of the algorithms is used. this includes the calculation of different algorithms complexity and its applicability, taking into account frame and slot times, minimum number of samples and estimation bandwidth. the complexity of the algorithms as a function of key parameters is used. based on these estimated functions, the execution time of the algorithms was calculated. through the use of matlab package, which is used as reference for the calculation a dsp system with 400 mflops processing power. most algorithms can be executed within 400 µs. it’s provided also a method of two step estimation for further reduction of the execution time. through this approach, a significant reduction was achieved for some combination of algorithms. key words: wideband, direction of arrival, array antenna, estimation, doa. في مصفوفية الهوائيات الطورية الوصوِلاتجاهقدير طريقة لت ايهاب عبد الرزاق حسين. سعد سفاح حسون د. د كلية الهندسة/ جامعة بابل كلية الهندسة /جامعة بابل قسم الهندسة الكهربائية قسم الهندسة الكهربائية مقدمة المعقدة المعتمدة الخوارزمياِت حيث تم استخدم ).doa (الوصولإتّجاه طريقة جديدة لتقدير حااقتر ا البحثفي هذتم نظر االعتبار في آخذينه، اتيتضمن حساب تعقيِد الخوارزمياِت المختلِف وتطبيق حيث. لهذا التقدير الحقيقيعلى قابلية الزمن األعدد والأوقاتَ الشقَّ واإلطارلبارامتراِت كدالة ل تعقيد الخوارزمياِت تم استخدم. يموجِة التقديرال العينات وعرضدنى ِمن تم ) matlab(من خالل برنامج . قد تم حسابهلخوارزمياِت االدوال التقديرية فان زمن تنفيذهذه واستناداً ل. الرئيسيِة وقت أكثر الخوارزمياِت يمِكن َأن تُنفّذَ ضمن. ات للحساب كمرجعmflops 400ذات قدرة معالجة ) dsp(استخدام منظومة 400 µs.يزوتم ت لقد للتقليل تينخطود طريقة ِمن فان تم انجازها في هذا البحثالحسابات التي خالل هذه من . التنفيذ زمن ِمن .ةخوارزميالكثر من هزاُأنجفي زمن التنفيذ قد تم هام هذا التقليل ال al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 46 introduction due to the lmds (local multipoint distribution system) system standardization process being held during the present year, the proposed system is based on the main standard documents: the european etsi bran hiperaccess [acampora et. al.] and the american ieee 802.16.1 wirelessman [deliverable d2.1]. as both systems have enough common characteristics, a single modified system was defined here. the coverage area is divided in rectangular cells of four 90o sectors, each of them covered by one or more sectorial antennas. the physical layer is a combination of time division duplex (tdd), time division multiplex (tdm) in the downlink and time division multiple access (tdma) in the uplink. therefore, the channel bandwidth is time-slotted and users are required to provide explicit or implicit information regarding their needs for bandwidth. the bandwidth management is based on granted access and access requests in contention or polling mode and the traffic is classified in a similar way as in asynchronous transfer mode (atm). the intended bit rate is up to 155 mbps, employing multilevel modulations. as a tdd frame, the uplink and downlink transmissions share the same frequency, but are separated in time. the frame has a fixed length, but the length of each sub-period is a system parameter that may be dynamically modified. the frame time is 1ms. table (1) reports the main network (cellular) level characteristics of the proposed system. the available bandwidth in both directions is defined with a granularity of one time-slot, which is a multiple of 4 modulation symbols. the pulses are shaped employing a raised-cosine filter with a certain roll-off factor. the modulation rate is selected in order to obtain an integer number of time-slots within each frame. the baud rate depends on the roll-off factor and the channel size. the channel bandwidth is 28mhz taking into account a 1 ms frame duration and a roll-off factor of 0.25. therefore, for a symbol rate of 22.4 mbaud (symbol period is 0.0446 µs) the duration of each time slot will be equal to 0.179µs or a multiple of this value. the downlink sub-frame starts with a preamble for synchronization and equalization duties, based in one or more 16-symbols constant amplitude zero auto-correlation (cazac) sequences. the preamble is followed by the protocol control data, which mainly maps the assignation of the different time intervals in the frame. finally, the data is transmitted in physical strength order. the downlink transmission is governed by the base station (bs) and therefore operates in a broadcast mode, free of collisions. the data are transmitted in order of modulation robustness. the control information is always transmitted with the most robust physical mode. 1. slot-based beam switching approach. the main issue when the proposed beamforming capabilities of the beamformer are introduced in the bs, is how to cover a 90o sector employing a directive antenna. in this research, a solution that employs a space switched single-beam antenna covering the whole sector from the base station instead of the traditional omnidirectional or sectorial antenna is proposed, as depicted in figure (1). this approach differs from others in that the bs covers the service region with a narrow beam, which can be rapidly scanned to a number of different positions depending on the geographical user position [d3.1, d3.2]. this beam-switching approach matches perfectly to a time based system, as the bs antenna is illuminating only in the desired direction and just at the appropriate time. as seen previously, the frame multiplex and access schemes are a combination of tdm in the downlink and a tdma in the uplink (both in the same radio-channel as the tdd operation mode was chosen). in both downlink and uplink a protocol data control zone and a data transmission zone may be distinguished. the downlink control information is used to manage the system, to grant the required bandwidth by users and to map the different zones of the frame. the uplink signaling zones are used for unsolicited access in a contention mode, or unicast or multicast polling, for bandwidth request and configuration issues, etc. the control information zone must be broadcasted to all the active users in the sector. an also, all the users present in the sector should be able to access into the signaling zone. this is clearly infeasible with a beam-switched antenna as it al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 47 only points to a certain portion of the sector at a given instant of time. two approximations to overcome this problem were identified [d5.1] and investigated [etsi ts101-999 v1.1.1, godara]: the inter-frame or frame-based beam-switching and the intra-frame or slot-based beam-switching. the frame-based beam-switching is based onto the sub-sectorization concept. the subsectorization consists on dividing a 90o sector in, e.g. four 22.5degrees sectors. each sub-sector will act as an independent sector. this way each beam position may be viewed as a kind of subsector, but only one of them can be active at each instant of time. however, with the given latency requirements of these systems (given by the frame duration of 1ms) the frame duration in each subsector, dependent of the number of beam positions, would lead to very inefficient bandwidth solutions as shown in [godara]. the slot-based beam-switching solution has been chosen as the most optimal approximation for the convergence of the reference standards. this solution is based onto the control information replication idea. in this way, the control information would be retransmitted for all the beam positions in a kind of scanning. as may be seen in figure (2) the use of the channel is shared between the equivalent sub-sectors but during a frame, as the beam is pointed to the desired terminal, which is equivalent to an “overall-sector” frame. however, this replication introduces protocol overhead and might make this approximation also unfeasible. the minimization of the control information in the slot-based beam-switching is required. an adapted medium access control (mac) protocol was developed in to minimize the control information replication [godara]. it should also be remarked that the proposed slot-time based switching implies that a switching time in the ns range is required. for a given bandwidth and bit rate the efficiency depends on the ability of pointing the beam to different users as quick as possible during the guard time between slots. the guard time is 8 symbols [acampora et. al.], so that, for the symbol rate of 22.4 mbaud, the guard time will be 357 ns. therefore switching times on the ns range are required. 2. doa estimation requirements the proposed system deals also with the following problem: in mobile systems, tracking becomes a must. the system must decide when a mobile should be pointed with an adjacent beam instead of the one being used, so it is a discrete tracking. doa estimation must be done at uplink transmission. it can be based on a training sequence of constant power or on a pilot tone of lower frequency modulated on the carrier frequency (40 ghz), but in any case the duration of these signals should be much lower that the time assigned to each user inside each uplink sub-frame: * training sequence: the training sequence could be the burst preamble added in the uplink data burst. the short burst preamble consist of 16 or 32 symbols (0.71 and 1.43 µs respectively), which are a repetition of 8 or 16 cazac sequences that are transmitted using the four corner points of the modulation constellation (maximum power). * pilot tone: the short-duration tone will be located after the burst preamble. the main drawback is that an additional hardware would be necessary in the user equipment in order to generate the pilot tone. one possible approach to overcome this drawback is to generate an additional training sequence (with a total length of 8, 16 symbols) after the burst preamble, so that, choosing an appropriated sequence (for instance 1, -1, 1, -1 …) a pilot tone can be generated at lower integer multiples of the symbol rate, i.e. 11.2, 5.6, 3.733 and 2.8 mhz. doa estimation at if/bb level the conventional doa estimation approach, which measures the maximum output power of different beams pointing to different angular positions, has fundamental resolution limitation. the digital signal processing (dsp) based algorithms such as subspace based methods or parametric methods have the high resolution required to achieve an accurate doa estimation to resolve closely spaced signal sources. thus, the estimation quality can be improved using powerful algorithms. an al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 48 accurate estimation is also a very useful task for the network management. the other advantage of the dsp based approach is the flexibility that different algorithms can be easily replaced without additional hardware, only loading new software code. in addition doa estimation can be directly applied for the high bandwidth data signals. consequently, no additional hardware for the transmission of extra pilot signal is required. the estimation of the direction of arrival is an essential part for steering and forming the field distributions of array antennas in mobile communication systems. the spatial distribution of the mobile subscribers has to be determined with high accuracy in order to determine the desired look directions and (in case of beam forming) the nulls for suppressing interfering signals. in the previous deliverable [horneffer and plassmann], we proposed the set up and measurement concept for doa estimation experiment using base band signal processing. critical parameters are pointed out and we explore the solutions for proper adaptation to the system architecture. the implementation of the base band signal processor has been already finished. study on adaptation aspects to the proposed system. we can identify the critical points concerning adaptation to the system architecture as following: a) according to the system specifications, the real time capability of the system is an important issue to switch to its user simultaneously. thus, the calculation of the processing power of the algorithms is a useful estimate for the assessment of the real time ability. b) the amount of the samples that are available within allocated time duration of each user must be estimated. c) the proposed system provides a high bandwidth data transmission up to 155 mbit/s. the base band processor of the doa estimator has a limited small bandwidth compared with that data rate. this fact seems to be a critical point for the practical implementation of the system. 1. computational complexity estimation the real time ability of a digital system is a topic related to the computational complexity of the algorithms. the applicability of the algorithms in real time may be assessed by estimating their execution time [ieee 802 committee]. as a result of this estimation, the complexity can be formulated as a function of some key parameters extracted from the algorithms. the choice of an algorithm and the amount of samples for the proper estimation are also related topics to the result of complexity estimation. in the digital signal processing, the complexity of an algorithm can be simply estimated by counting all involved operations in the calculations. as a result of this estimation, the complexity is given as a function of key parameters, such as number of array elements, number of samples and amount of angular space, in which the maximum value is searched. for counting operations, the following rules are valid: * additions and subtractions are one flop if the operands are real and two if complex. multiplications and divisions count one flop each, if the result is real and six flops, if it is not. elementary functions count one if real and more if complex. * first, we verify some key calculations of the mostly used functions in the algorithms. a) the calculation of sample covariance matrix requires 2m2 (4n −1) operations. b) singular value decomposition (svd) needs 10(m3+3.3m2+13m −40) operations. c) the process searching for maximum value requires log(nθ) operations. the used parameters above are the number of antenna elements m, the number of samples n, the number of azimuth angles nθ, the number of repeated loops nrep, and the number of users k=1. the complexity estimation is performed for the following algorithms: bartlett, multiple signal classification (music), estimation of signal parameters via rotational invariance techniques (esprit) and alternating projection (ap) [kortke and schubert]. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 49 the estimation results are given as a function of above mentioned parameters and listed in the table (2). a calculation example about the required number of operations can be taken from table (3). in this calculation, following parameters are used: * number of array elements m=4. * number of samples n=300 bits. * number of azimuth angles nθ=181 (between –90 degrees and 90 degrees with 1 degree angular resolution). * number of loop repeats nrep=5. * number of signal k=1. for the calculation of the execution time, we also assume that a digital signal processing (dsp) system with a processing power of 400 mflops is used. such dsp system is usually available in the market (as shown in table (4)). the most algorithms may be executed for above parameters within 400 µs. but the ap algorithm needs more processing power, while the esprit algorithm requires the smallest calculation time because of no need of the search process. 2. two step estimation for reducing complexity in case of single user, the estimation process can be partitioned in two steps. first, we make a rough estimate with a simple algorithm, e.g. bartlett with a rough angular resolution (e.g. angular resolution 5 degrees). as a result of this estimation, we obtain an angular range to be estimated accurately. in the second step, we select a small angular range based on the angular range estimate of the first step. we apply a high resolution estimation algorithm or the same algorithm only for this small angular range. the main advantage of this approach is that we reduce the complexity for the same angular estimation accuracy (as shown in figure (3)). basically, the rough estimation can be achieved in the analogue domain as well as in the digital domain. an estimation result can also be taken from the table (4). the complexity estimation is carried out for the previous parameters. the combined approach bartlett/ap shows a significant reduction of complexity compared with the estimation of ap alone, although the estimation accuracy remains the same. 3. the amount of signal samples related to the real time ability assuming that both uplink and downlink sub-frames together count as 1ms frame and several users are transmitting on each uplink sub-frames. we can expect that each user is transmitting during tens of milliseconds on each frame. for instance, if we further assume that the duration of the each uplink and downlink sub-frames is 0.5 ms and 10 users are active within this sub-frame time duration, the allocation time of the each users tuser for obtaining the signal samples for doa estimation may be 50 µs. note that the base band processor of the doa experimental system has a constant sampling frequency fsample=16 mhz. the amount of samples available within the allocation time tuser can be calculated as following: samplesvalued complex 008f tn sampleusersample =×= (1) whether or not, the amount of samples is sufficient for the proper estimation. 4. bandwidth considerations the array receiver of the doa estimation experimental system has a small bandwidth compared with the transmitted data signal provided in the proposed system. the transmitted channel bandwidth is 28 mhz and the proposed bit rates are between 44.8 mbit/s and 134.4 mbit/s corresponding to qpsk and 64-qam using a roll-off factor of 0.25 (see tables (1)). assuming that no extra pilot signal or training sequence are available for doa estimation, the transmitted high rate data signal or the synchronization signal must be used for the estimations, which provides much higher bandwidth than the doa estimator. suppose that single user signal is active, the received signal at the array antenna can be written as: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 50 )(a)t(s)t(sre θ= (2) where a(θ)=[1, exp( jµ0 ), ..., exp( j(m −1) µ0 )]t is the steering vector and µ0−π sin(θ) is the spatial frequency. because of the small bandwidth of the base band array receiver, only a small part of this transmitted spectrum (2.5 mhz) will be filtered. thereby, the sampling theorem can not be obeyed. consequently, we have to under-sample the signal, so that the transmitted signal can not be detected correctly. in the base band, the received signal will be sampled with a constant sampling frequency fsample (16 mhz) and a sampling period tsample (62.5 ns). the base band signal can now be written as: ( ) ( ) ( )θaktskts samplesamplere = (3) however, as we can see from the equation (3), the doa information remains unchanged after under-sampling. as a result, we can also perform the doa estimation for high rated data signals directly without exploiting a pilot signal. thus, the bandwidth of the doa estimator is not a critical parameter. calibration of the array before the doa estimation is carried out in the real environment, the array must be calibrated, because the measured data may include errors such as [robey et. al, ziskind and wax]: * offset error. * different amplification of individual antenna signals. * different phase shift of individual antenna signals. since the calibration is accomplished in the digital domain, no additional hardware is needed. a) correction of offset error. if signals incident on the array antenna with enough power and time duration, we can calculate the mean power of in phaseand quadrature-components for each signal path of the array receiver. the mean powers for each signal path can be written by: ∑ = = n 1n k,ik,i )n(xn 1 m (4) ∑ = = n 1n k,qk,q )n(xn 1 m (5) where i and q the indexes for in phaseand quadrature-components, k for the array number, n the number of samples. thus, the correction of offset error can be achieved by subtracting the mean power from the measurement vector x. k,ik,ik,i mxx ~ −= (6) k,qk,qk,q mxx ~ −= (7) b) compensation of different amplifications of individual antenna signals. unfortunately, the subcomponents of doa estimator have not the desired same characteristics. these differences affect unequally each of signal paths. thus, the received signal powers of different paths must be compensated. first, the signal power for in phaseand quadrature-components must be calculated separately as following: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 51 ∑ = = n 1n 2 k,ik,i )n(x ~ n 1 p (8) ∑ = = n 1n 2 k,qk,q )n(x ~ n 1 p (9) after that, we calculate the normalizing factors di,k and dq,k for in phaseand quadraturecomponents. k,i k,i p 1 d = (10) k,q k,q p 1 d = (11) the compensation of the amplifications can be achieved now by multiplying the signals kix , ~ and k,qx ~ with the normalizing factors di,k and dq,k. k,qk,qk,ik,i g o x ~d*jx~dx~ += (12) c) elimination of phase errors the ideal signal output vector has the following form in the noiseless case: x=a(θ)s(t) (13) where s(t) is the transmitted signal and a is the steering vector with: a(θ)= [ ] t ))sin()1k(j())sin(j( e,,e,1 θπθπ −−− l (14) the signal output vector of a real system with phase errors can be formulated as following: xreal = θa(θ)s(t)= ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎝ ⎛ k 2 1 j j j e0 e 0e φ∆ φ∆ φ∆ o a(θ)s(t) (15) if a single signal incidents on the array, the vector vp of the covariance matrix rxx must be the estimate of θa(θ) for the real system. the vector vp contains the eigen values of the matrix θa(θ). if a single signal is transmitted from the azimuth angle at 0 degrees, the diagonal elements of the matrix θ are corresponding to the elements of vector vp because of a(θ)=[1,1,...,1]. from this, the phase errors are determined. the phase errors can be compensated by multiplying the matrix k with the array output vector gox ~ . g ox ~kx = .where al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 52 ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎝ ⎛ = * k,p * 2,p * 1,p v0 v 0v k o (16) for the phase calibrations of the other angular directions the same formula (15) can be applied by the following modification: ⊗= realreal xx ~ a(θk)*=θa(0)s(t) (17) where the operator ⊗ denotes component wise multiplication and a(θk)* is the conjugate of the a priori known steering vector of the currently measuring directions. estimated results a calibration example and estimation errors are shown in figure (4) as a function of azimuth angles. the measurements were performed in the angular range between -45 degrees and 45 degrees with 5 degree angular steps. the number of use samples n is 1000. the used estimation algorithms are esprit, music, alternating projection and bartlett algorithms. estimation errors are obtained by applying the calibration steps above. the calibration errors over whole angular ranges are below 0.2 degrees. in figure (5) the root mean square errors (rmse) are shown as a function of the number of samples and the signal to noise ratio (snr). the number of samples n is varied between 10 and 4500. the signal noise ratio is changed between -10 db and 10 db in 5 db steps. single user signals in 5 degrees angular distance are measured. the estimation errors over all measured angular range are averaged. the used estimation algorithm is music. at high snr values, the estimation performance is nearly not influenced by the number of samples, since there is a big performance difference at low snr values. for all cases, 320 samples are a good choice for the reasonable performance. figure (6) shows the estimation result performing high bandwidth signal. the maximum estimation error is smaller than 0.4 degrees. the errors are derived from the imperfect calibration. however, there is no limitation because of the bandwidth as one have expected. therefore, doa estimation can be applied directly for high bandwidth received data signals as well as for pilot signals. conclusions the adaptation aspects on the doa estimation at if/bb level have been studied in this point. the doa estimation at if/bb level has been investigated. the adaptation aspects of the doa estimation using base band signal processing have been studied. we identified critical points concerning the implementation and adaptation to the system proposed here. related to the real time capability of doa estimator the complexity estimation of the algorithms is performed. this includes the calculation of different algorithms complexity and its applicability, taking into account frame and slot times, minimum number of samples and estimation bandwidth. as a result, the complexity of the algorithms could be given as a function of key parameters. based on these estimated functions, the execution time of the algorithms was calculated. as reference for the calculation a dsp system with 400 mflops processing power was used. most algorithms can be executed within 400 µs. also, a method of two step estimation for further reduction of the execution time is provided. through this approach, significant reduction was achieved for some combination of algorithms. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 53 assuming that each user is continuously transmitting during 50 µs of the up-link and taking the sampling frequency of the doa experimental system of 16 mhz into account, the amount of the available samples n within this allocation time may be 800 complex valued samples. by means of the simulated results, the number of samples n=320 was identified as a good choice for proper estimation. references acampora a. s., chu t., dragone c. and gans m. j., (1991), “a metropolitan area radio system suing scanning pencil beams”, ieee trans. on comm., pp. 141-151, vol. 39, no. 1, january. deliverable d2.1, ist-2000-25390 obanet project, (2001), “system conception and specification: network and beamformer aspects”, may. deliverable d3.1, ist-2000-25390 obanet project, (2001), “coverage area management specifications”, august. deliverable d3.2, ist-2000-25390 obanet project, (2001), “coverage area adaptation protocols”, december. deliverable d5.1, ist-2000-25390 obanet project, (2001), “performance evaluation of single beam beamformers (transmitting and receiving modes) in the 40ghz band”, october. etsi ts 101 999 v1.1.1 (2002) broadband radio access networks (bran); hiperaccess; phy protocol specification. godara l. c., (2004), “smart antennas”, crc press llc horneffer m. and plassmann d., (1995), “directed antennas in the mobile broadband system”, proceedings in race mobile telecommunication summit, cascais, portugal, november. ieee 802 committee, (2001), “standard air interface for fixed broadband wireless systems”, p802.16/d5-2001, october. kortke a., schubert m., (2001), “design of pilot signal assisted and blind beamforming algorithms for space time rake receiver”, internal project report at hhi, june. li j., stoica p., (1998), “comparative study of iqml and mode direction-of-arrival estimators”, ieee transaction on signal processing, vol. 46, no.1, january. milligan t. a., (2005), “modern antenna design”, second edition, john wiley & sons, inc. robey f.c., fuhrmann d.r., koerber m.a., (2001), “array calibration and modeling of steering vectors” signals, systems and computers, 2001. conference record of the thirty-fifth asilomar conference on , vol. 2 , pp. 1121 –1126. ziskind i. and wax m., (1988), “maximum likelihood localization of multiple sources by alternating projection”, ieee transaction on acoustics, speech, and signal processing, vol. 36, no.10, october, pp. 1553-1560. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 54 table (1). report of the main proposed system parameters. number of sectors for cells four 90o sectors mobile 100 m cell size fixed 1 km frequency of operation 40 ghz duplexing method tdd access method tdma frame duration 1 ms channel size 28 mhz bit rate/modulation format 155 mbps /multi-level table (2). complexity estimation for the doa algorithms as a function of key parameters [kortke and schubert, li and stoica, milligan]. algorithm estimate computational operations bartlett )log()]1(26)[1()14(2 2 θθ nmmmnnm +−+++− music )log()]1(26)[12( )]2(2)1(6[)1()40133.3(10)14(2 232 θθ nmmmn mmmmmmmnm +−+++ −+−−+−+++− esprit )36202(125)40133.3(10)14(2 23232 −−++−+++− mmmmmmnm alternating projection ( ) ( ) ( )[ ][{ ] ( )}θ θ nm mmmmmmnnnm rep 10 222 log2 126655.0322142 ++ −++++++− table (3). complexity estimation example: nθ=181, n=300, m=4, nrep=5 and k=1. algorithm number of operations [flops] calculation time by [400 mflops/s] bartlett 65520 163 µs music 88790 221 µs esprit 37160 92 µs alternating projection 705910 1764 µs bartlett+ap: rough estimate (resolution 5o) and accurate estimation (resolution 1o) 156050 399 µs bartlett+ bartlett: rough estimate (resolution 5o) and accurate estimation (resolution 1o) 47070 117 µs al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 55 table (4). an example of dsp system (source: analog device). adsp-21065l adsp-21160n adsp-21161l clock cycle 66 mhz 95 mhz 100 mhz instruction cycle time 15 ns 10.5 ns 10 ns mflops sustained 132 mflops 380 mflops 400 mflops mflops peak 198 mflops 570 mflops 600 mflops 1024 point complex fft (radix with bit reversal) 279 µs 97 µs 92 µs fir filter (per tab) 15 ns 5.2 ns 5 ns iir filter (per biquad) 61 ns 21 ns 20 ns matrix multiply (pipelined) [3×3]*[3×1] [4×4]*[4×1] 136 ns 242 ns 47 ns 83 ns 45 ns 80 ns divide (y/x) 91 ns 31 ns 30 ns inverse square root 136 ns 47 ns 45 ns figure (1). (a) traditional sector with a 90o antenna. (b) our modification employing a beamswitching antenna. figure (2). slot-based beam-switching. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 56 figure (3). reduction of execution time of doa estimation using two steps estimation. (a) (b) figure (4). calibration example, estimation errors vs. azimuth angles, snr=25 db ((a) graph and (b) table of results). (a) (b) figure (5). root mean square errors (rmse) as a function of the number of samples and snr: number of samples n = [10, 20, 40, 80, 160, 320, 640, 1280, 2560, 4500] and snr = [10, 5, 0, -5,10] db ((a) graph and (b) table of results). rough estimation accurate estimation angular range estimates doa received signals 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 -50 -40 -30 -20 -10 0 10 20 30 40 50 azimuth angle (deg.) e st im at io n er ro r (d eg .) esprit ap music bartlett estimating error (deg.) azimuth angle esprit ap music bartlett -45 0.08 0.1 0.1 0.1 -40 0.108 0.1 0.1 0.1 -35 0.053 0.032 0.032 0.032 -30 0.032 0.012 0.012 0.012 -25 0.059 0.032 0.059 0.032 -20 0.03 0 0 0 -15 0.039 0.038 0.038 0.038 -10 0.05 0.038 0.038 0.038 -5 0.068 0.0797 0.0797 0.0797 0 0.089 0.0797 0.0797 0.0797 5 0.052 0.797 0.797 0.797 10 0.11 0.122 0.112 0.122 15 0.13 0.0.133 0.0.133 0.0.133 20 0.12 0.133 0.133 0.133 25 0.17 0.112 0.112 0.112 30 0.154 0.1595 0.1595 0.1595 35 0.17 0.1 0.1 0.1 40 0.101 0.08 0.069 0.08 45 0.0395 0.021 0.021 0.021 0 0.5 1 1.5 2 2.5 3 3.5 10 100 1000 10000 number of snapshots r m se (d eg .) (-10 db) (-5 db) (0 db) (5 db) (10 db) rmse (deg.) number of samples -10 db -5 db 0 db 5 db 10 db 10 3.15 1.9 0.7 0.45 0.4 20 1.15 0.501 0.32 0.2 0.22 40 0.8 0.25 0.25 0.12 0.22 80 0.6 0.2 0.18 0.085 0.1 180 0.33 0.19 0.12 0.07 0.09 300 0.26 0.18 0.1 0.01 0.01 600 0.2 0.16 0.03 0 0 1100 0.195 0.16 0.03 0 0 2500 0.192 0.15 0.03 0 0 4500 0.192 0.15 0.03 0 0 al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 57 (a) (b) figure (6). doa estimation example performing high bandwidth signal, angular range between – 45 degrees and 45 degrees in 5 degrees steps, snr=25 db, maximum error= 0.4 degrees. ((a) graph and (b) table of results). 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 -50 -40 -30 -20 -10 0 10 20 30 40 50 azimuth angle (deg.) e st im at io n er ro r (d eg .) esprit ap music bartlett estimating error (deg.) azimuth angle esprit ap music bartlett -45 0.07 0.105 0.105 0.105 -40 0.035 0 0 0 -35 0.07 0.105 0.105 0.105 -30 0.035 0 0 0 -25 0.031 0 0 0 -20 0.025 0 0 0 -15 0 0 0 0 -10 0.025 0 0 0 -5 0.06 0.107 0.107 0.107 0 0.125 0.107 0.107 0.107 5 0 0 0 0 10 0.25 0.3 0.3 0.3 15 0.34 0.4 0.4 0.4 20 0.049 0 0 0 25 0.04 0 0 0 30 0.073 0.107 0.107 0.107 35 0.07 0.107 0.107 0.107 40 0.23 0.2 0.2 0.2 45 0.035 0 0 0 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 12 numerical investigation of various thickness wall in square enclosure with a porous medium dr. maathe abdulwaded a dr. sahar abdul fattah a a department of mechanical engineering, university of al-mustansiriyah received 12 september 2013 accepted 17 february 2014 abstract convectional flow within the porous material of various models has received extensive attention in the last years.this interest is because of its wide range of applications, for example, in high performance insulation of buildings, chemical catalytic reactors, packed sphere beds, grain storage and such geophysical problems as the frost heave. in this study a numerical simulation of unsteady natural convection modes in a square enclosure filled with a porous medium having different wall thickness(0.2,0.3,and 0.5) has been done .it has been taken darcy number effect (10 -3 ,10 -4 ,10 -5 and 10 -6 ), with thermal conductivity ratio (1,5,10)these variables have been studied on the stream velocity and temperature effect for two cases of different heating ways one of them all down plate heated and the other for partial heating .the results show that increased in 𝜏 dimensionless time is reflected in increase vortex scale and the thermal plum comes nearer to internal surface of right wall the increase in da number leads to increase both sizes and convective cells intensity also the use of different materials cause different thermal ratio the increase of thermal conductivity ratio corresponds to increase in thermal conductivity of solid. the thickness increasing causes decreased by the heat transfer. the average nusselt number increase with increase of darcy number and increase with increase in thickness of material for the both cases. key words: porouce medium, numerical analysis, enqlusour دراسة عددية وتحققية لمغلف مربع ذو جدار بسمك متغير ومملوء بوسيط مسامي م.د.معاذ عبد الواحد ذيب م.د.سحر عبد الفتاح عبود ةقسم الهندسة الميكانيكي -كلية الهندسة –الجامعة المستنصرية الخالصة في المناطق المغلقة والتي تحتوي على مادة بينية نالت الكثير من االهتمام في اآلونة األخيرة هذا االهتمام ناتج من ان انتقال الحرارة ذلك في المشاكل الجيوفيزيائية .في هذه الدراسة التطبيقات الواسعة في المواد العازلة ,والمفاعالت الكيمائية, والمخازن الحبيبية ,وك الجوانب للحيز معزولة ومن األعلى يتم تغير المستقرة في داخل حيز مغلق مع وجود مادة بينية للحالة الغير تمت اعداد دراسة عددية تم سمك الصفيحة اما من األسفل فهناك حالتين حالة الجدار من األسفل كليا مسخن اما الحالة الثانية فان التسخين يكون لجزء معين. سمك الصفيحة العلوية دراسة تأثير ) 10, وعدد دارسي )(,.2,,.2.0,2 -6 ,10 -5 ,10 -4 ,10 -3 ( و تأثير نسبة الموصلية لحالتين مرة لحالة التسخين الكلي لصفيحة السفلية ( هذه المتغيرات تم دراستها على المائع وعلى درجات الحرارة 2,,,,,الحرارية) . السفليةصفيحة الجزئي للومرة أخرى لحالة تسخين سرعة وشدة من النتائج أظهرت ان زيادة الزمن الالبعدي يؤدي الى زيادة الدوامات وان زيادة عدد دارسي يؤدي الى زيادة حجم كال درجات الحرارة .واستخدام مواد مختلفة الموصلية الحرارية فان المواد ذات الموصلية الحرارية العالية ستؤدي الى زيادة نسب الموصلية al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 13 ة في السمك تؤدي الى نقصان في انتقال الحرارة في حيز .اما عدد نسلت يزداد بزيادة عدد دارسي وزيادة تأثير سمك السطح بينما الزياد العلوي ولحالتين مغلف.وسيط مسامي , تحليل عددي,الكلمات الداللية: list of symbols: da:darcy number. fo:fourier number. g :gravitational acceleration. h:height of enclosure(m). k:thermal conductivity ratio. ks:thermal conductivity of solid material (w/m.k). kg:thermal conductivity of gas (w/m.k). l:width of enclosure(m). nu:average nusselt number. ra:rayleigh number. pr:prandtl number. t:temperature (k). t :time (sec). u, v: velocity components in the x-and y-direction. u, v: dimensionless velocity components in x, y directions. x, y and x, y: space coordinates and dimension space coordinates. greek symbols ρ: density (kg/m 3 ). α: effective thermal diffusivity (m 2 /s). β: thermal expansion coefficient (1/k). µ: dynamic viscosity of the fluid (ns/m 2 ). ν: kinematic viscosity (m 2 /s). ω: dimensionless vorticity. ψ: dimensionless stream function. θ: dimensionless temperature. τ: dimensionless time. introduction: convective flows within porous materials have occupied the central stage in many fundamental heat transfer analyses and have received considerable attention over the last few decades. convective heat transfer analysis in porous media has been the subject of a very powerful research over the past years due to the importance of related industrial and technological applications, which include geothermal heat extractions, heat removal from nuclear reactors , exothermic reactions in packs, bed reactors, storage of grains, food processing, the spread of pollutants underground, electronic boxes, and solar collector technology. in a wide variety of such problems, the physical system can be modeled as a two-dimensional, rectangular enclosure filled with a homogeneous porous medium, with the vertical walls held at different temperatures and the connecting horizontal walls considered adiabatic. in the past two decades, numerous experimental and theoretical investigations had al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 14 been devoted to the steady-state natural convection flow and heat transfer in such enclosures. a study for a steady two-dimensional natural convection in a rectangular cavity containing a darcy porous medium. they have analyzed the problem by a number of different techniques and the results obtained by these different methods are in good agreement with each other and with the experiments[9].natural convection in porous media for localized heating from below has been found that the heat transfer increases by increasing the length of the heat source[5]. laminar natural convection has been studied in enclosures bounded by a solid wall with its outer boundary at constant temperature while the opposing side has a constant heat flux. two-dimensional equations of conservation of mass, momentum and energy, with the boussinesq approximation are solved using a finite difference method. it is found that the heat transfer is an increasing function of the rayleigh number,wall to fluid conductivity ratio, enclosure aspect ratio and a decreasing function of the wall thickness. it passes from a maximum for the inclination angle of about 80°[2]. a paper deals with the results of an experimental and numerical study of free convective heat transfer in a square enclosure characterized by a discrete heater located on the lower wall and cooled from the lateral walls.the study analyzed how the heat transfer develops inside the cavity at the increasing of the heat source length the local nusselt number is evaluated on the heat source surface and it shows a symmetrical form raising near the heat source borders. graphs of the local nusselt number on the heat source and of the average nusselt number at several ra are finally presented [1]. a mathematical simulation has made for unsteady state natural convection modes in a square cavity filled with a porous medium having finite thickness heat –conducting walls with local heat source on condition of heterogeneous heat exchange with an environment at one of the external boundaries. numerical analysis was based on darcy –forchheimer model in dimensionless variables such as a stream function, a vortices vector and a temperature so the unsteady conjugate natural convection problem in a square enclosure filled with porous media has been numerically solved [4].a conjugate natural convection-conduction heat transfer in a square porous enclosure with a finite –wall thickness numerically for all heated down surface with constant thickness solid part,comsol multiphysics software has been used for solving the governing equations for different value of darcy number and thermal conductivity ratio and rayleigh number[7]. the target of this paper is a mathematical simulation of transient conjugate natural convection in a fluid porous medium in a square enclosure one of its faces having different thickness. mathematical model an enclosure of two dimensions filled with a porous medium as shown in fig (1).the two vertical walls are insulated ( .the bottom surface is heated to a constant temperature (th) and the upper surface is cooled to a constant temperature (tc) with different wall thickness .the thermo physical properties are of the fluid at a reference temperature is assumed to be constant, except the buoyancy term. the governing equations for unsteady two-dimensional natural convection flow in the porous cavity using conservation of mass,momentum and energy can be written as[8]: (1) ( ) ( ) (2) ( ) ( ) (3) al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 15 (4) in solid walls as in figure( 1): ( ) (5) equation (1-4) can be written in another form without pressure .in the rectangular coordinates the set of equations can be written in term of variables such as the stream function ψ and the vorticity ω [3].on the basis of new functions ψ-ω the equation (1-3) can be written as follows: ( ) ( ) (6) (7) the stream function 𝜓 and the vorticity are: (8) to set equations (5,6,7) in non-dimensional form the following relations are used: 𝜏 √ , mathematical model in non-dimensional form are in the porous medium (2 in fig 1): √ ( ) √ (9) (10) √ ( ) (11) in solid walls (1 in fig(1)): √ ( ) (12) average nusselt number is the integral of temperature : ̅̅ ̅̅ ̅ ∫ (13) al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 16 boundary condition non –dimensional boundary condition equations (9-12)are as follows[7]: (14) (15) (16) (17) where is the thermal conductivity ratio. model validation the boundary problem was solved by finite difference numerical method [6].in order to validate the work comparison of the obtained results with the results of other author has been done figure(2)and figure (3)shows good agreement. these comprehensive verification efforts demonstrated the robustness and accuracy of this computation. results and discussion in this study the following results are respectively presented where the numerical results introduce and discussion in details: effect of dimensionless time change: figure (4) and figure (6) shows the streamlines and isothermal lines for a change of time for da=10 -5 , ra=10 6 , fo=10 3 and for ksolid/kgas=5 on flow regime. increase in 𝜏 is reflected in increase vortex scale corresponding to counter clock wise motion which distorts the right convective cell .the thermal plum comes nearer to internal surface of right surface. effect of the darcy number: figure (5)and figure(7) at ra=10 6 ,𝜏=120,fo=10 4 , ksolid/kgas=5 at different darcy no. (10 -5 ,10 -4 & 10 3 ) the increase of darcy leads to increase both sizes and convective cells intensity that is caused by reduction of solid structure volume in the gas cavity. isothermal temperature distribution shows the appearance of a steady thermal plume above the heat source that reflects domination of convective heat transfer over the conductive heat transfer mechanism.when the da number increases the intensity of convection becomes stronger which implies that the convection heat transfer begins to dominate the thermal flow field in the enclosure. effect of thermal conductivity thickness figure (7) the effect of heat conductivity ratio on streamlines and temperature fields corresponding a convective heat transfer regime ra=10 6 ,da=10 -3 ,𝜏= 120 and a various value of thermal al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 17 conductivity thickness( 0.2,0.3,0.5&1 ).the increase in thermal conductivity ratio corresponds to reduction of thermal conductivity of solid walls material transition leads to redistribution of all determent variables. it can be seen that heat transfer decrease by increasing the solid wall thickness.it can be seen also that the strength of the flow circulation of the fluid porous medium is much higher for a thin solid wall.the flow circulation breaks up into a perfectly dual contrarotative cell at t=0.5 .this is because of the fluid adjacent to hotter wall has lower density than the fluid at the middle plane. effect of the thermal conductivity ratio for different material: figure (9) shows the thermal conductivity ratio (1,5,10)for the same variables it can be seen the effect on the fluid and temperature fields .the strength of the flow circulation of fluid porous medium is much higher than for thin solid top wall .so the fluid adjacent to the hotter surface which is the bottom wall has lower density than fluid at the middle .as result ,the fluid moves upward because of bouncy force .when the fluid reaches the top part of porous enclosure ,it is cooled ,so its density increase .the heat transfer decrease by increasing the solid wall thickness. effect of darcy number on average nusselt number: figure (10 ) shows the effect of darcy number on the average nusselt number. it can be seen increasing darcy number increasing nusselt number and this increase heat transfer because it depends on the permeability of porous medium and for all heated plate the value of darcy is more than the value of partial heat. effect of thickness of material on average nusselt number: figure(11)shows the effect of thickness on average nusselt number .it can be seen that for all heated plate the nusselt number increase with increasing the thickness and the same behavior when the plate is partially heated and this is because of the increasing of domination of convection heat transfer by increasing the buoyancy force inside the porous medium . conclusions: the main concluded points of this study may be summarized as following: 1increased in 𝜏 is reflected in the increase vortex scale and the thermal plume comes nearer to internal surface of right wall. 2the increase in da number leads to increase both sizes and convective cells intensity. 3the use of different materials cause different thermal ratio the increase of thermal conductivity ratio corresponds to increase in thermal conductivity of solid. 4the thickness increasing causes decreasing by the heat transfer. 5the average nuesslt number increases with increasing of darcy number for the both cases . 6the average nuesslt number increase with increasing of material thickness ratio for all heated plate with partial heat. refrences: [1] b.calcagni , f.marsili ,m.paroncini" natural convective heat transfer in square enclosures heated from below" .applied thermal engineering 25(2005) pp.2522-2531 [2] ben yedder, r.; bilgen, e.: natural convection and conduction in trumbo wall systems. int. j. heat mass transfer 34 (1991)pp. 1237-1248. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 [3] greenkorn, r.a.: flow phenomena in porous media. marcel dekker, new york (1983). [4]mikhail a. sheremet, inna a.aleshkova "unsteady conjugate natural convection in a square enclosure filled with porous media" international journal of heat and mass transfer53(2010) pp.5308-5320. [5] prasad, v., kulacki, f. a.: natural convection in horizontal porous layers with localized heating from below. j. heat transf. 109, pp.795–798 (1987). [6] p.j. roache, computational fluid dynamics, hermosa, 1998. [7] h. saleh · n. h. saeid · i. hashim · z. mustafa " effect of conduction in bottom wall on darcy– bénard convection in a porous enclosure" transept porous med (2011) 88:pp.357–368. [8] tanmay basak, s. roy, t. paul, i. pop, natural convection in a square cavity filled with a porous medium: effects of various thermal boundary conditions ,int. j. heat mass transfer 49 (2006) pp. 1430–1441. [9] walker, k.l., homsy, g.m.: convection in a porous cavity. j. fluid mech. 87, pp.449–474 (1978). al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 19 t=tc t=tc metal metal porous medium porous medium t=th t=th (a) partly heated plate (b) all heated plate figure (2): temperature fields for ra=10 6 ,da=10 -3 , 𝜏=50 numerical results pop et al [8] figure (3): temperature fields for present study figure (1): shows the numerical model for the two cases al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 20 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 figure(4): streamlines 𝚿and temperature fields 𝚹 at different dimensionless time 10,60,100 ,120 ra=10 6 , da=10 -5 ,fo=10 3 ,ksolid/kgas=5 ,different material thickness for all heated plate. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 21 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 figure (5): streamlines 𝚿and temperature fields 𝚹 at different dimensionless time =120 ,ra=10 6 ,fo=10 4 ,ksolid/kgas=5 at different darcy number =10 -3 ,10 -4 ,10 -5 &10 -6 for all heated plate al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 22 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 figure (6): temperature field 𝚹 and streamlines 𝚿 for ra=10 6 , da=10 -3 ,fo=10 3 & kgas/ksolid=5 for different dimensionless time 𝜏=90,100,110 &120 heated for part of the down plate. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 23 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 figure (7): shows temperature field 𝚹 and streamlines 𝚿 for 𝜏=100, ra=10 6 ,da=10 -5 & fo=10 4 and for different thickness= 0.2, 0.3, 0.5 , where part of plate is heated. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 24 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 figure ( 8 ): shows the temperature fields 𝚹 and streamlines field 𝚿 for 𝜏=100, ra=10 6 fo=10 4 & ksolid/kgas=5 for different darcy number=10 -3 ,10 -4 & 10 -5 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 25 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 figure(9): shows temperature field 𝚹 and streamlines field 𝚿 for 𝜏=100, ra=10 6 , fo=10 4 ,da=10 -5 and different thermal conductivity ratio al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 26 0 0.5 1 1.5 2 2.5 3 3.5 4 0 0.0002 0.0004 0.0006 0.0008 0.001 0.0012 n u n u m b e r da number all heated plate partial heated plate figure (10): the effect of darcy number on the nusselt number for the both cases 0 1 2 3 4 5 6 7 0 0.1 0.2 0.3 0.4 0.5 n u ss e lt n u m b e r thickness of material all heated plate partial heated plate figure (11): the effect of thickness of material on the nusselt number for the both ases al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 161 experimental study of the friction factor in equilateral triangular duct with different types of vorex generators (obstacles) mohammed ghanem jehad university of anbar, mech. eng. dept. abstract: friction factors for fully developed flow in an equilateral triangular duct containing built-in vortex generators of delta wing, rectangular wing, pair of delta winglets, and pair of rectangular winglets have been investigated experimentally for reynolds numbers ranging from (24 500) to (75 750). the ratio of the crosssectional area of the test duct to that of the vortex generator (ad/avg) was remaining constant during experiments. the variable parameters were; type of vortex generator, vortex generator angle of attack, and reynolds number. the friction factor values for the smooth triangular duct are in good agreement with the existing data. the present results show that the friction factor is affected strongly by the wing greater than the winglet pair of vortex generators. the delta wing causes flow loss greater than the rectangular wing, while the flow loss accompany with the existence of the pair of deltawinglets is less than that of the pair of rectangular winglet. it is also observed that the friction factor is affected remarkably by the angle of attack of vortex generator. keyword: triangular duct, fully developed, friction factor, obstacle. أنواع مختلفة من النمو في مجرى مثلث المقطع باستخدام تجريبية لمعامل ا�حتكاك كاملدراسة )عوائق(مولدات الدوامية محمد غانم جھاد قسم الھندسة الميكانيكية، كلية الھندسةجامعة ا�نبار :الخالصة ثلث، والجناح المستطيل، والجنيح تم اجراء دراسة تجريبية لبيان تاثير غرز مولدات الدوامية نوع الجناح الم 500(عدد رينولدز تراوح بين المثلث، والجنيح المستطيل على جريان الهواء داخل مجرى مثلث المقطع ولقيم تم تثبيت نسبة مساحة المقطع العرضي للمجرى الى مساحة مولد الدوامية خالل التجارب، ). 75 750(و ) 24 كانت نتائج . نوع مولد الدوامية، وزاية ميل مولد الدوامية، وعدد رينولدز: وكانت المتغيرات في هذا البحث هي بينت النتائج الحالية ان . االختبارات للجهاز بدون وجود مولدات الدوامية جيدة مقارنة مع نتائج البحوث السابقة كما وان المولد نوع .معامل االحتكاك يكون متاثرًا بشكل كبير بالمولدات نوع الجناح اكثر منه من نوع الجنيح al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 162 الجناح المثلث يولد هبوط ضغط اقل من الجناح المستطيل، في حين ان خسائر الجريان المرافقة لوجود الجنيح كما ولوحظ ان تغيير زاوية ميالن مولد الدوامية تؤثر . المثلث هي اقل من تلك المرافقة لوجود الجنيح المستطيل .بشكل واضح على معامل االحتكاك .، عائقمعامل االحتكاكمجرى مثلث، تام النمو، : مات المفتاحيةالكل nomenclature lest of symbols a internal cross-sectional area of the orifice plate (m2). da internal cross-sectional area of the test duct (m 2). vga vortex generator area (m 2). c constant. d constant. hd hydraulic diameter (m). f darcy’s friction factor. of standard friction factor(without obstacle). h height of the vortex generator (m). l distance between two tandem static pressure taps (m). l length of the vortex generator (m). •m air mass flow rate (kg/s). p wetted perimeter of the walls of the duct (m). ∆∆∆∆ p pressure drop between the static pressure taps (pa). re reynolds number. s distance between tips of winglet pair (m). intb inlet air bulk temperature ( ok). outtb outlet air bulk temperature ( ok). ft air bulk film temperature ( ok). u mean velocity of the air (m/s). al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 163 w length of the side of the test duct (m). zx distance of wingtip from the leading edge of the test section (m). greek symbols ββββ angle of attack of vortex generator (degree). ρρρρ air density (kg/m3 ) µµµµ absolute viscosity (pa.s). υυυυ kinematic viscosity (m/s2) introduction: in the development of recent industrial world, the reduction in the heat exchanger size and enhancement in their performance for heat transfer had a great interest of investigators. but there are always economical factors to reduce the costs of heat transfer process. the need for high performance thermal systems due to study the increase in the pressure drop associated with the augmentation operations in heat transfer. use of vortex generators for heat transfer enhancement is one passive method that generates vortices which creates high turbulence in fluid flow over heat transfer surfaces. aly et al. (1978) performed a numerical and experimental study for fully developed airflows through an equilateral triangular duct for high values of reynolds number. they have found that the measured and predicted friction factor have a good agreement with the blasius1 equation for friction factor in smooth circular tubes. an experimental study was performed by altemani et. al. (1980) to determine the entrance region, fully developed heat transfer and fluid flow characteristics for turbulent airflow in an unsymmetrical heated equilateral triangular duct. they have found that the circular –tube friction factor results deviate from those of equilateral triangular duct, even when the hydraulic diameter is employ. in (1986) chegini et. al. studied theoretically and experimentally the friction factors for fully developed flow in triangular duct for two apexangles with and without fins for a wide range of re number. this study showed that the equilateral triangular duct has smaller scatter of friction factor data compared with the isosceles. a numerical and experimental study of flow and heat transfer characteristics in a rectangular channel with built-in wing vortex generator was investigated by biswas et. al. (1992) and laith (2008). biswas et. al. have seen that the combined spanwise average friction factor (fxre) increases approximately linearly with the angle of attack of generator, and more affected with re number. laith found that the friction factor changes significantly when re numbers increased. as an extension of the work of biswas et. al. (1992), dep et al. (1995) and biswas et al. (1994) studied the effect of the delta-wing and wingletpair type vortex generator on a fluid flow and heat transfer characteristics through a rectangular channel. biswas et al. (1994) have found that the loss (corresponding to the combined spanwise average friction factor coefficient) due to the winglet-pair is less than that due to the wing. kotcioglu et al. (1998) investigated the rectangular-wing in the rectangular channel as in a way of divergent and convergent arrays. they observed that the pressure drop is influenced strongly by the inclination angle of vortex generator. sabah et. al. (2007) studied numerically the effect of exist of 1 f = 0.316/re0.25 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 164 multi–types of turbulators on the fluid flow and temperature distribution for laminar and turbulent flow in a rectangular duct. the influence of vortex generators angle and louver angle on heat transfer and flow loss in laminar channel flows was numerically studied by chung (2003). the purpose of this paper is to highlight the effect of the four basic types of the vortex generators experimentally on the pressure drop gradient in a triangular duct. these four basic types of the vortex generators are shown in figure (1). experimental apparatus: the experiments were performed in an open–loop airflow circuit. the first air is encountered of regulator valve upstream wise of the blower, and then ducted to a circular tube which is provided by an orifice plate flowmeter in the axial mid-length to measure the air flow rate. the upstream end of the circular tube is coupled with the blower by using a flexible tube to minimize the vibration that occurs during blower operation and the downstream end mated with a hydrodynamic development section. the hydrodynamic development duct has an equilateral triangular cross section. a convergent contraction aluminum part was used to transit from circular tubing of the upstream piping system to the downstream triangular cross-section. the air exiting the hydraulic development section passes through the test section which they mated together at the same horizontal straight line and have an identical cross-section. the scheme of the current experimental apparatus is shown in figure (2). during a course of experiments, reynolds number was varied between (24 500) and (75 750). the development and test section were of identical internal dimensions; side of triangle=15 (cm), and hydraulic diameter=8.66 (cm). the respective axial lengths of the development and test sections were (24 hd ) and (15 hd ). the experiments tests were performed in the fluid laboratory, engineering college, university of anbar. the volumetric flow rate of air was measured by an orifice plate meter whose pressure taps were located one diameter upstream and half-diameter downstream as published in roberson et. al. (1997) and spencer et. al. (1982). the internal diameter ratio of the orifice plate and the tube is (0.7). some parameters were to be constant during the experimental apparatus design. these parameters are; the ratio of the cross-sectional area of the test duct to that of the vortex generators (ad/avg), the distance of the wingtip from the leading edge of the test duct (xz), the number of the vg punched in the duct, and the distance between the tips of winglet pairs (s). the geometry of the vortex generator was dependent upon the inclination angle (β) to keep the ratio (ad/avg) is to be constant. this can be seen clearly in table (1) and figure (3), (4), and (5). the variable parameters are; the type of the vortex generator, the vortex generator angle of attack which is (20, 30, and 40) degree, and reynolds number varying from (24 500) to (75 750). the vortex generator thickness is assumed negligible. the test section has seven static pressure taps located at various positions along the axial direction. at any given axial location, the taps were also located in the circumferential direction to sense any pressure variation in that direction. the three taps at any given location jointed together to form one end. the difference in pressure was measured by connecting the inclined manometer two ends to each tandem two measuring points by pvc tubes. a mercury thermometer is used to measure the input and output temperature of the test section. the air properties were estimated at the air bulk film temperature that is defined as follows, al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 165 holman (1976): 2 outin btbt ft + = …(1) the mass flow rate can be computed by the following equation: uam ρ=. … (2) the experimental data are represented in the standard form of friction factor as a function of reynolds number defined as follows. streeter (1979): p mhdu µν .4 re == …(3) the symbol ( hd ) is the hydraulic diameter of the triangular duct that can be defined as follows, streeter (1979): p a d dh 4= …(4) the friction factor f, known as darcy friction factor in the literature, is defined as, streeter (1979): ] 2 [ 2u d l p f h ρ × ∆ = …(5) results and discussion: for checking the velocity of the experimental apparatus, figure (6) shows the comparison between the current data without any obstacle and the literature experimental data. the results of petukhov-popov, prandtl, and blasius were developed for circular tubes, while the data of altemani al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 166 was for triangular duct as published in research of altemani et. al.(1980). as shown in figure (6), the present data over predicts that of altemani by about (4.5) percent, whereas it is lower than that of blasius, petukhov-popov, and blasius by about (5, 6.86, and 8) percent respectively. this comparison indicates that the experimental rig is satisfactory. figure (7) shows the axial distribution of the (f x re) along the test section for re=24500 while keeping the angle of attack of vortex generator constant. it is apparent that the flow loss associated the existence of the wing-type is greater than that associated the winglet pair of vgs. this is because the wing-type causes a pressure drop region behind the trailing end of the vortex generator greater than that it is caused by the winglet pairs of vortex generators, and the air flow is circulated smoothly with the existence of winglet-pair type while if the wing-type is existence the air flow is circulated strongly. the pressure drop caused by rw is larger than that of dw. also, we obtain a (f x re) for the case of rwp greater than that of dwp. this performance gives a behavior similar to that of the rectangular channel as investigated by tiggelback (1994). as expected, the friction factor value remains unchanged throughout in the duct for the flow without any obstacle. for example, at β=20 deg the (fxre) for the case of dw at a location (x/dh=2), is about (93.9%) more than that for the plane duct flow, while for the case of dwp over the (f x re) value for plane channel about (57.4%). this behavior can also be clearly remarked in the figure (8) when re=75750 and β=40 degree. figure (9) shows the effect of the varying of the vortex generator angle of attack while keeping the ratio of (ad/avg) constant. it is observed clearly that the friction factor increases monotonically with (β) because the vortex circulation increases which increases resistance and a higher value of friction is obtained. for example, at β=30o, the friction factor for the case rw promotes by about (24.7) percent more than that for β=20o as shown in figure (9-a). figure (10) exhibits the effect of re number on the average friction factor through the test section. it seems that the friction factor is reversely proportion with reynolds number. for example, in the case of rwp the ( f ) is about (56.7%) when re=24 500 and β=40o greater than that for re=75 750 as shown in figure (10-d). a correlation of the friction factor is determined as a function of reynolds number to compare the fourth cases data. the correlation obtained from the current experimental data is: 2re π β d c f = …(6) the values of the variables c and d in eq.(6) are tabulated in table (2). concluding remarks: depending on the results presented and discussed, the main conclusions of this study can be summarized as follows: 1. the flow loss in a triangular duct (corresponding to the friction factor) due to the al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 167 winglet-pair is less than that due to the wing. 2. the pressure drop increases strongly with the angle of attack of vortex generator (> 30 degree). 3. the difference in the pressure drop caused by the delta-winglet pair and rectangular – winglet pair is very slightly. 4. the friction factor changes significantly when the reynolds numbers increased. references: 1. altemani, c.a.c., & sparrow, e.m., november 1980,“turbulent heat transfer in an unsymmetrically heated triangular duct”, asme journal of heat transfer, vol. 102, pp. (590–597). 2. aly, a.m.m., trupp, c. & gerrard a.d., 1978,“measurements and prediction of fully developed turbulent flow in an equilateral triangular duct” j. of fluid mech. vol.85, part 1, pp. (57–83). 3. biswas, g., and chattopadhyay, h., 1992,“heat transfer in a channel with built–in wing– type vortex generators”, int. j. heat mass transfer. vol. 35, no. 4, pp. (803–814). 4. biswas, g., dep, p., and biswas, s., august 1994,“generation of longitudinal streamwise vortices–a device for improving heat exchanger design”, asme journal of heat transfer, vol. 116, pp. (588–597). 5. chegini, h. & chaturvedi, s.k., august 1986,“an experimental and analytical investigation of friction factors for fully developed flow in internally finned triangular ducts”, journal of heat transfer, vol. 108, pp. (507– 512). 6. chung, j.d., park, b.k., and lee, j.s., 2003 ,“the compined effects of angle of attack and louver angle of a winglet pairon heat transfer enhancemet”, j. enhanced heat transfer, vol.10, number.1, pp(31-43). 7. dep, p., biswas, g., and mitra, n. k., 1995,“heat transfer and flow structure in laminar and turbulent flows in a rectangular channel with longitudinal vortices”, int. j. heat mass transfer, vol. 38, no. 13, pp. (2427–2444). 8. holman. j. p., 1976,”heat transfer”, 4th edition, mcgraw–hill, inc. 9. kotcioglu, i., ayhan,t., olgun, h., and ayhan, b., “heat transfer and flow structure in a rectangular channel with wing – type vortex generator”, tr. j. of engineering and environmental science, 22, 1998, pp. (185–195). 10. laith. j.h., 2008,“numerical and experimental investigation of heat transfer augmentation using vortex generators”, ph.d. thesis, university of technology. 11. ligrani, p. m., ortiz, a., joseph, s. l., and evans, d. l., january 1989,“effects of embedded vortices on film – cooled turbulent boundary layers”, journal of turbomachinery, vol. 111, , pp. (71–77). 12. roberson, john a., and crowe, clayton t., 1997,“engineering fluid mechanics “, 6th edition, jone wiley and sons inc., usa. 13. sabah, t.a., waheed, s.m., & laith, j.h., 2007,“numerical investigation into velocity and temperature fields over smooth and rough ducts for several types of turbulators” eng. and technology, vol.25, no.10. 14. spencer, e.a., june 1982,“progress on international standardization of orifice plates for flow measurement”, int. j. heat & fluid flow, vol. 3, no.2, pp. (59 – 66). 15. streeter victor l. & wylie e. benjamin, 1979,“fluid mechanics “, 7th edition, mcgraw– al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 168 hil, inc. 16. tiggelbeck, st., mitra, n.k., & feibig, m., november 1994,“comparison of wing type vortex generators for heat transfer enhancement in channel flows”, asme journal of heat transfer, vol. 116, pp. (880 – 885). table (1) test model geometry, all values in mm. 20 degree 30 degree 40 degree rw dw rwp dwp rw dw rwp dwp rw dw rwp dwp vortex height (h) 16 23 20 31 23 30 16 23 32 44 11 16 vortex length (l) 46 65 33 46 44 63 32 44 50 70 35 50 area avg(mm 2) 500 500 500 500 500 500 500 500 500 500 500 500 ad/avg 20 20 20 20 20 20 20 20 20 20 20 20 distance of the wingtip from leading edge (xz) 1dh 1dh 1dh 1dh 1dh 1dh 1dh 1dh 1dh 1dh 1dh 1dh distance between tips of winglet pairs (s) 20 20 20 20 20 20 table (2) values of the variables c and d in eq.(6) case var β c d dw 20 0.723 0.549 30 2.036 0.668 40 1.762 0.666 rw 20 0.798 0.564 30 1.254 0.612 40 2.466 0.680 dwp 20 0.161 0.427 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 169 30 0.408 0.538 40 0.614 0.587 rwp 20 0.203 0.443 30 0.367 0.523 40 1.103 0.635 figure (1) schematic of longitudinal vortex generators types; a-delta wing, brectangular wing, c-delta winglet pair, d–rectangular winglet pair. rw dw rwp dwp xz s l β w h figure (3) schematic of the geometry of the duct with the delta-winglet pair. figure (4) shows the ratio of (ad/avg) that is equal to 20. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 170 figure ( 6 ) friction factor results re x 10-3 20 30 40 50 60 70 80 f x 1 0 2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 current data petukhov-popov [2] blasius [2] altemani [2] rw rwp dw dwp h s/ 2 l figure (5) shows elevation and plan view of different vgs. β w/2 β al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 171 figure ( 8 ) axial distribution (fxre) along the test section at ββββ =40o and re=75 500. x/d h 0 2 4 6 8 10 12 14 16 f x r e 0 10000 20000 30000 40000 rw dw dwp rwp without obstacle location of the obstacle figure ( 7 ) axial distribution of (fxre) along the test section at β=40o and re=24500. x/d h 0 2 4 6 8 10 12 14 16 f x r e 0 3000 6000 9000 12000 15000 without obstacle rw dw dwp rwp location of the obstacle al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 172 (a) (b) 15 20 25 30 35 40 45 f x 1 0 2 6 8 10 12 14 16 rw dw rwp dwp 15 20 25 30 35 40 45 f x 1 0 2 2 4 6 8 10 12 14 16 rw dw rwp dwp β β (a) (b) figure ( 9 ) effect of the angle of attack of vortex generators on the average friction factor. (a) re=24500, (b)re=75750. fig ( 10 ) effect of reynolds number on the average friction factor in the duct. (a)dw, (b)rw, (c) dwp and (d)rwp. re x 10-3 20 30 40 50 60 70 80 f x 10 2 1 2 3 4 5 6 without obstacle 20 deg 30 deg 40 deg re x 10-3 20 30 40 50 60 70 80 f x 1 0 2 1 2 3 4 5 6 7 without obstacle 20 deg 30 deg 40 deg re x10-3 20 30 40 50 60 70 80 f x 10 2 1 2 3 4 5 without obstacle 20 deg 30 deg 40 deg ( d ) ( b ) re x 10-3 20 30 40 50 60 70 80 f x 10 2 1 2 3 4 5 without obstacle 20 deg 30 deg 40 deg ( a ) ( c ) <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 87 numerical simulation for heat transfer analysis in laminar flow of cuo-water nano-fluid in tubes dr. emad abdula khazal e-mail: emad.ab74@gmail.com dr. khalid baker saleem e-mail: khalidb77@gmail.com department of mechanical engineering, engineering college, university of basrah, basrah –iraq received on 09 february 2016 accepted on 10 november 2016 abstract this paper presents a two-dimensional numerical analysis to study the laminar heat transfer and flow characteristics of cuo–water nanofluids through a tube at constant heat flux boundary condition at tube wall. based on the single-phase approach, the effects of different parameters such as nanoparticle volume concentration (1% 5%), and reynolds number (500 2100) for various axial locations of tube with cuo–water nanofluids as working media were discussed in detail. the finite volume method and simple algorithm are utilized to solve the governing equations numerically. the numerical results shows that with enhancing reynolds numbers, local nusselt number increases. the variations of the local nusselt number relative to volume concentrations are not uniform. according to the results, an equation was obtained for nusselt number predicted data using the dimensionless numbers. the relation between local nusselt number and re number also compared for other previous work. there are agreement in results and found the maximum difference between results reach to be 6.3% approximately which validate the current computational model. keywords: nanofluids; heat transfer; tubes , laminar flow -(اوكسید نحاسالنمذجة العددیة لتحلیل انتقال الحرارة للجریان الطباقي لمائع متناھي الصغر ماء) في األنابیب د. عماد عبدهللا خزعل e-mail: emad.ab74@gmail.com د. خالد بكر سلیم e-mail: khalidb77@gmail.com قسم الھندسة المیكانیكیة -كلیة الھندسة -جامعة البصرة الخالصة في ھذا البحث تم دراسة الحل العددي لنموذج ثنائي البعد لجریان طباقي وانتقال الحرارة لمائع متناھي الصغر لخلیط من ثابت على الجدران.استنادا إلى طریقة المائع الماء و اوكسید النحاس (مائع نانوي) خالل األنابیب معرض إلى فیض حراري ) على ٢١٠٠-٥٠٠%) ورقم رینولدز (٥ -% ١الواحد تم دراسة تأثیر عدة موثرات من ضمنھا نسبة حجم المائع النانوي ( طول جریان األنبوب مملوء بخلیط من الماء واوكسید النحاس. تم حل المعادالت الحاكمة باستخدام طریقة الحجوم الصغیرة و یزداد معدل انتقال الحرارة وكذلك بزیادة النسبة (re)كطریقة عددیة. ظھرت النتائج بزیادة رقم ینولدز (simple)صیغة وجمیع األرقام الالبعدیة. أیضا (nu)الحجمیة للمائع النانوي. استناداً إلى النتائج المستحصلة تم التنبوء بمعادلة بین رقم نسلت سنلت ورقم رینولدز متعدد مع عمل سابق وكان ھناك توافق بین النتائج وأقصى فرق في النتائج یصل إلى تم مقارنة النتائج لرقم % تقریبا، مما یؤكد موثوقیة النموذج الحسابي الحالي.٦.٣ al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 88 nomenclature the following symbols are used generally throughout the text. others are defined as and when used. symbols meaning units cp specific heat at constant pressure j/kg.k d diameter of the tube m k thermal conductivity w/m.k nu nusselt number p pressure pa pr prandtl number q'' heat flux w/m 2 re reynolds number t temperature k v velocity vector m/s x distance along axis m greek letters a thermal diffusivity m 2 /s f volume fraction r density kg/m 3 m molecular dynamic viscosity n.s/m 2 subscripts bf base fluid f fluid nf nanofluid s solid of particle 1. introduction fluids heating and cooling represent the essential parts in large portions of industrial applications, for example, power stations, production processes and transportation. the majority of the strategies for heat transfer depend on the structure variety, vibration of the heated surface, and injection or suction of fluid[2,5]. heat transfer inside the conventional fluids represented by water, oil and ethyleneglycol innately has low thermal conductivity in contrast with the metals and metallic oxides. consequently, fluids with suspended solid particles are expected to have better heat transfer properties [12]. an innovative strategy for enhancing heat transfer by using ultra fine solid particles in the fluids has been utilized widely during the last decade. the term nanofluid alludes to these sorts of fluids by suspending nano-scale particles in the base fluid [8]. alumina and copper oxide are the most regular and cheap nanoparticles which might be used inside the experimental investigations [21]. choi and eastman [9],1995, utilized the particles in nanometer dimensions as a suspended solution. they demonstrated that the nanofluid thermal conductivity considerably increased. lee et al. [16] confirmed that the suspension of 4% with 35 nm cuo particles in ethylene glycol had 20% augmentation in the thermal conductivity. choi [10], 2001, watched 60% improvement in the thermal conductivity of engine oil with 1.0% carbon nanotube. das [11],2003, examined the temperature reliance of thermal conductivity in the nanofluids. they had been determined that a 2–4 increment in the thermal conductivity of nanofluid can occur over a temperature scope of 21–51°c. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 89 bai [4],2008, investigated the heat-transfer character of nanofluids and applied nanofluids to engine cooling system. cfd numerical simulation technique became employed to analyze the utility value of nanofluids in engine cooling. the simulation results showed that nanofluids could improve engine heat dissipating capacity and cu-water nanofluids had better heat-transfer ability. they likewise found that with increment of nanoparticles concentrations, more enhancement of engine disspating capacity will happen. they concluded further to that when the concentration become 5%, the heat dissipating capacity would enhanced by 44.1%. namburu [19],2009, numerically examined turbulent flow and heat transfer of al2o3, cuo, and sio2 nanoparticles suspended in ethylene glycol and water based fluids in a straight pipe. they showed that sio2 with nanoparticle diameter of 20 nm offers the best thermal conductivity enhancement because of better viscosity value of lower nanoparticle diameter. zamzamian [23],2011, investigate the effect of forced convective heat transfer of nanofluids of aluminum oxide and copper oxide prepared in ethylene glycol in turbulent flow. they discover vast enhancement in convective heat transfer coefficient of the nanofluids in contrast to the base fluid. furthermore, their outcomes show that with expanding nanoparticles concentration and nanofluid temperature, the convective heat transfer coefficient of nanofluid will increases. naik [18], 2013, analyzed turbulent convective flow of cuo nanofluids of propylene glycol– water as the base fluid and flow through a circular tube, subjected to a regular and uniform heat flux at the wall. they found that nanofluids containing extra concentrations have proven higher heat transfer coefficient. they compared their numerical results with the experimental data and affordable appropriate agreement is performed. sheikholeslami,2014, [22] observed numerically the impact of natural convection heat transfer in a nanofluid (cuo) crammed enclosure with elliptic internal cylinder. they observed that nusselt number increments with an increment each of nanoparticles volume fraction, rayleigh numbers and inclination angle. . likewise, they found that expanding rayleigh number prompts a lessening in heat transfer enhancement. for high rayleigh number the minimum heat transfer enhancement ratio occurs at slanted elliptic cylinder is 90º. hsien-hung and shuhn-shyurng [14],2014, numerically research the convective heat transfer of water-based al2o3 nanofluids flowing through a square cross-section duct with a fixed heat flux under laminar flow conditions. they investigated the influences of nanoparticle concentration and peclet number on the heat transfer attributes of al2o3-water nanofluids. the nanoparticle diameter is 25 nm and six particle concentrations (0.2, 0.5, 1, 1.5, 2, and 2.5 vol.%) are taken into consideration. they confirmed that the heat transfer coefficients and nusselt number of al2o3water nanofluids increment with expansions within the peclet number and similarly particle volume concentration. the heat transfer coefficient of nanofluids is elevated via 25.5% at a particle volume concentration of 2.5% and a peclet quantity of 7500 as contrasted with that of the base fluid (pure water). bouhalleba and abbassi [6],2016, analyzed numerically heat transfer and fluid flow of natural convection in inclined cavity full of cuo-water nanofluid and partially heated. . the prandtl number is kept constant at 7.02 corresponding to water. aspect ratio and solid volume fraction are changed from 0.5 to 4 and from 0% to 4% respectively, and the inclination angel is varied from 0° to 90°. they found that the efficiency of heat transfer is enhanced by the increment of nanoparticles ratio into base liquid; but there is an optimum solid volume fraction which promotes the heat transfer rate. additionally they found that the diameter of solid particle is an imperative parameter that influences the heat transfer efficiency, its effect is more critical than the concentration itself. ningbo [20], 2016, studied a three-dimensional numerical analysis of the laminar heat transfer and flow characteristics of al2o3–water nanofluids through a flat tube at constant heat flux boundary condition. they discovered with their numerical results that with the addition of nanoparticle will enhances the heat transfer and the pressure loss of base fluid in all of the flat tubes at different reynolds number and temperature. both the relative average convective heat transfer coefficient and pressure drop can be enhanced by increasing nanoparticle volume concentration and al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 90 reducing nanoparticle size. and the heat transfer and pressure drop enhancements of nanofluids are more evident at smaller reynolds number and higher temperature. also, they derived new correlation models for thermal conductivity and viscosity of al2o3–water nanofluids and confirmed it. in this research, the convective heat transfer in the developed region of the tube flow containing water and cuo nanofluid under constant heat flux was examined by the usage of computational fluid dynamics (cfd) techniques. cuo nanoparticles with average diameter of 29 nm was dispersed in water. the nanofluids with three different cuo nanoparticle concentrations (1%, 3.0%, and 5% volume concentrations) were used. effects of nanoparticle concentrations on the convective heat transfer coefficient were also investigated with different reynolds number and find the best correlation for heat transfer coefficient. a comparison of the results predicted form the current model with experimental data from literature will made. 2. problem description and governing equations the basic flow configuration, under study, is shown in fig. 1. a two dimensional pipe have 1.2 m length and 4.75 mm inner diameter was spotted in the simulation. the continuity, momentum and energy equations for a two dimensional incompressible laminar flow has been solved using appropriate boundary conditions by mean computational fluid dynamics technique. following assumptions have been made: two-dimensional problem, there is no viscous dissipation, no gravity acts, the fluid properties are constant and radiation heat exchange was assumed negligible. at steady state conditions using above assumption, the governing equations as given below [13]: continuity equation: ( )nf. 0rñ =v (1) momentum equation: ( ) ( )nf nf. p .r mñ = -ñ + ñv v v (2) energy equation ( ) ( )nf nf. c t . k trñ = ñ ñv (3) the effective physical properties of the nanofluids in the above equations are: the vis f is given by [7, 13]. ( ) 2.5 1 f nf m m f = (4) the density of the nanofluid is given as: ( )1nf f sr f r fr= + (5) the thermal diffusivity of the nanofluid is given as ( ) nf nf p nf k c a r = (6) the heat capacity of the nanofluid is expressed as [1, 15]. ( ) ( )( ) ( )1p p p nf f s c c cr f r f r= + (7) in this research, the single-phase method was implemented. solid particles with less than 100 nm diameter were spotted inside the single-section approach. furthermore, the thermal conductivity of nanofluid is approximated as given in references[1, 15]. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 91 ( )( ) ( )( ) 2 2 2 s f f s nf f s f f s k k k k k k k k k k f f + = + + (8) thermophysical properties of the nanofluid are given in table (1). in current formulation, thermophysical properties of the nanofluid are assumed to be constant. the boundary conditions are prescribed as follows: · at the tube inlet: u(y) = ui and t = ti = 298 ºk · at the tube outlet: pressure outlet boundary 0p = · at the wall : no-slip condition, q''=5000 w/m 2 . the above boundary conditions are shown in fig. 1. the total length of the computational domain is taken as (l = 1.2 m) to ensure fully developed outlet boundary condition, and the constant heat flux of 5000 (w/m 2 ) as a boundary condition at the pipe wall was applied. 3. numerical procedure the geometry and the gird were generated using design modeler and meshing programming in ansys-15. the design modeler and meshing are an integrated preprocessor for cfd analysis. the physical boundary conditions for the geometry are defined as inlet, pressure outlet and wall of the tube as shown in fig. 1. the continuum became the fluid. then, the mesh file was successfully conducted into the fluent (code 15). for single phase approach, solid particles with diameter less than 100 nm have been noticed. consequently, single phase approach was selected for nanofluid modeling [17]. the fluid was entered the pipe with a constant velocity in every run. the constant heat flux of 5000 (w/m 2 ) as a boundary condition at the pipe wall was applied. 4. effect of the mesh refinement it is important to have a good mesh to get an accurate solution. there are some general guidelines to create a good mesh. a good mesh should be fine enough with high quality cells and good distribution of these cells is essential. moreover the mesh should not have more cells than the available computer resources can handle. the grid independence was checked. the cases considered are as following: for two dimensional pipe the hexahedral structured elements mesh was used. four mesh sizes were used and the governing equations were solved based on these four meshes respectively. the results obtained from these meshes at re = 1700 and volume fraction 3% are summarized in table (2). from these results (table (2)) it can be seen that the solution becomes independent of grid size and increasing the size of mesh more than the mesh no. 3 do not have a significant effect on the results just increasing the run time and memory requirements. therefore for more accuracy the mesh no.3 (3600 cells) will be considered in all calculations. 5. results and discussion results were obtained for single-phase flow using relations mentioned at article 2 for different values of re, f and axial distance (x/d) with a fixed heat flux at tube wall (i.e. q=5000 w/m 2 k). al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 92 the local heat transfer coefficient and local nusselt number were evaluated using the following equations: ( ) ( ) h x d nu x k = (9) ( ) '' h( ) ( ) ( ) w f q x t x t x = (10) where, d, q″, k, tw and tf are pipe diameter, heat flux, thermal conductivity of the fluid, tube wall temperature and nanofluid bulk temperature, respectively at an axial position. fig. 2 shows the contours of temperature distribution at the end part of the pipe for cuowater nanofluid with re values as 500 , 1300 and 2100 which illustrated in figs a , b and c respectively (with d=29 nm and f=5%). from the figs. it seen that the nanofluid is heated via the pipe wall and its temperature increases with the axial distance. the temperature of nanofluid along the pipe with re=500 is more and varies sharper than it at re=1300 and re=1700 and because the fluid at lower re will more expose to the wall heat flux and that makes it more heated and its temperature rises when compared with the larger re values and this leads to make the heat transfer coefficient at the larger re value (i.e. re=2100) become bigger. fig. 3 shows the variation of heat transfer coefficient with re at an axial location (x/d=150) with 29 nm particles diameter. the results obtained for both pure water and cuo-water nanofluid with three different f values (i.e. f=1%,3% and 5%). the results obtained shows that the heat transfer coefficient was increases with increasing re and this due to the increment of fluid velocity which makes the fluid less heated and this cause decrease in temperature difference between the wall temperature and fluid bulk temperature, also it seen that the heat transfer coefficient for pure water is less than it in nanofluid because the particles ratio makes the fluid more heated. fig. 4 shows the heat transfer coefficient in tube versus axial location for pure water and cuo-water nanofluid with three different concentrations (f=1%,3% and 5%). as seen from the fig the heat transfer coefficient decreases with increasing the axial distance because there is increase at the temperature difference between the tube wall and fluid bulk temperatures, also the heat transfer coefficient for nanofluid is higher than it in pure water because the cuo particles make the fluid more heated then decreases the temperature difference between wall temperature and bulk temperature then h will increases. fig. 5 shows nusselt number versus re at axial distance (x/d=150) for pure water and cuowater nanofluid with three particle concentrations (i.e. f=1%,3% and 5%) with nanofluid diameter of 29 nm. usually nu will increases with increasing the axial distance due to increasing h as describe by fig.3 but nu for pure water is higher than it in cuo-water nanofluid and this due to the increment in thermal conductivity of nanofluid than thermal conductivity of pure water and the thermal conductivity of nanofluid is increase when f increases which make reduction in nu as illustrated in the fig. fig. 6 shows nusselt number versus axial distance for pure water and cuo-water nanofluid with three particle concentrations (i.e. f=1%,3% and 5%) with nanofluid diameter of 29 nm. the figure shows that nu will decreases along the axial distance due to h decrement and it decreases too with increasing f due to increasing of thermal conductivity of nanofluid as illustrated above. figs. 7 and 8 shows dimensionless temperature profile along vertical distance at different axial locations with re=500 for pure water and cuo-water with f=5% respectively. it is important to note that such a decrease of the fluid temperature at the tube wall exists along the tube length and seems to be more interested toward the tube end. these results have clearly shown the helpful al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 93 impact because of the nanoparticles, an impact that may be clarified by the way that with the presence of these particles, the thermal properties of the resulting blend have been largely enhanced. fig. 9 shows profiles of wall temperature along tube axial distance for re=500 and q=5000 (w/m 2 ) at vertical level y=4 mm for both pure water and cuo-water nanofluid with different concentrations (f=1% and 5%). the fig shows the increment in fluid temperature with the axial distance because the fluid is more heated towards the tube end its temperature incraeses. the concentration of the particles increases the temperature of cuo-water more than the pure water temperature and that clearly observed at the larger concentration of particles (i.e. f=5%) due to increases. fig. 10 represent a comparison of numerical and experimental results for al2o3 nanofluid with particle diameter 45 nm at axial distance (x/d=147) [3]. the fig shows for the first four heat transfer coefficient values there were a reasonable agreement between the numerical and experimental data and there is little difference between the results and experimental data with a maximum error determined to be around 6.3% so the determined results from the current model are acceptable. 6. correlation the convective heat transfer of the nanofluid relies upon various factors such as heat capacity, viscosity, particles volumetric concentration and axial location. based on the results of numerical computations of new correlations are developed for nusselt number as a function of reynolds number range (500 -2100), particles volume fraction range (1% 5%) with pure water and axial location (x/d). 0.18 1.17 0.28 nu 5.96 re (1 ) (x / d)f = + (11) this relation of correlate nusselt number data for the nanofluid as shown in fig. 11. the correlated nu data were in good agreement with the nu simulated with 2% maximum error. 7. conclusions in the present study numerical simulation of cuo-water nanofluid flowing in a tube with uniform heating at the wall was examined with different flow parameters, the calculations were performed using ansys fluent (cfd code) at the developed region of the tube. the results shows that the heat transfer coefficient enhanced with increasing the concentration of the nanoparticles and re number. also both of heat transfer coefficient and nu number decreases with the axial distance and nu number is more decreases with increasing the particle concentration. a new correlation derived for the predicted nu number from the simulation based on re, axial distance (x/d) and particle volumetric concentration (f) which shows good agreement with the nu simulated results. the current numerical model was validated with experimental data from the literature and it gives a quite agreement in the lower re numbers. references [1] abu-nada, e., masoud z., hijazi, a., "natural convection heat transfer enhancement in horizontal concentric annuli using nanofluids", int. communications j. heat and mass transfer, vol. 35, pp. 657–665, 2008. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 94 [2] ahuja as, "augmentation of heat transport in laminar flow of polystyrene suspension", i. experimental and results. j. appl phys vol. 46, no. 8, pp. 3408–3416, 1975. [3] anoop, k.b., sundararajan, t., das, s.k. "effect of particle size on the convective heat transfer in nanofluid in the developing region", international journal of heat and mass transfer vol. 52, pp. 2189–2195, 2009. [4] bai, m., xu, z., and lv, j., "application of nanofluids in engine cooling system," sae technical paper 2008-01-1821. [5] bergles ae, webb rl, "augmentation of convective heat and mass transfer". winter annual meeting of the american society of mechanical engineers, asme, new york, n.y, 1975. [6] bouhalleba, m. & abbassi, h. "numerical investigation of heat transfer by cuo-water nanofluid in rectangular enclosures". heat transfer engineering, vol. 37, issue 1, pp. 13-23, 2016. [7] brinkman, h. c., "the viscosity of concentrated suspensions and solution", j. chem. phys., vol. 20, pp. (571-581), 1952. [8] choi, s.u.s., "enhancing thermal conductivity of fluids with nanoparticles". in: siginer d.a., wang h.p. (ed.), developments and applications of non-newtonian flows, fed-vol. 231/mdvol. 66 asme, new york, pp. 99–105, 1995. [9] choi sus, eastman ja, "enhancing thermal conductivity of fluid with nanoparticles". asme international mechanical engineering congress & exhibition, san francisco, ca, 1995. [10] choi sus, zhang zg, yu w, lockwood fe, grulke ea "anomalous thermal conductivity enhancement in nanotube suspensions". appl. phys. lett., 79(14) , pp. 2252–2254, 2001. [11] das sk, putra n, theisen p, roetzel w, "temperature dependence of thermal conductivity enhancement for nanofluid". journal of heat transfer, vol. 125, pp. 567–574, 2003. [12] eastman ja, choi sus, li s, yu w, thompson lj, "anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles". appl phys lett 78(6), pp. 718–720, 2001. [13] ho, c. j., chen, m. w. and li, z. w., "numerical simulation of natural convection of nanofluid in a square enclosure: effects due to uncertainties of viscosity and thermal conductivity", int. j. heat mass transf., vol. 51, pp. 4506-4516, 2008. [14] hsien-hung ting and shuhn-shyurng hou, "investigation of laminar convective heat transfer for al2o3-water nanofluids flowing through a square cross-section duct with a constant heat flux", j. materials, vol. 8, pp. 5321-5335, 2015. [15] khanafer, khalil, vafai, kambiz, and lightstone, marilyn, "buoyancy-driven heat transfer enhancement in a two-dimensional enclosure utilizing nanofluids", int. j. heat and mass transfer, vol. 46, pp. 3639–3653, 2003. [16] lee s, choi sus, li s, eastman ja, "measuring thermal conductivity of fluids containing oxide nanoparticles". journal of heat transfer vol. 121, pp. 280–289, 1999. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 95 [17] moraveji mk, darabi m, hossein haddad sm, davarnejad r. "modeling of convective heat transfer of a nanofluid in the developing region of tube flow with computational fluid dynamics". int commun heat mass transfer vol. 38, pp. 1291–1295, 2011. [18] naik mt, vojkani e, ravi g. "numerical investigation of turbulent flow and heat transfer characteristics of pgw-cuo nanofluids". int j. m. m. mech eng, 2:141–5, 2013. [19] namburu pk, das dk, tanguturi km, vajjha rs. "numerical study of turbulent flow and heat transfer characteristics of nanofluids considering variable properties". int j ther sci; vol. 48, pp. 290–302, 2009. [20] ningbo zhao, jialong yang, hui li, ziyin zhang, shuying li, " numerical investigations of laminar heat transfer and flow performance of al2o3–water nanofluids in a flat tube", international journal of heat and mass transfer, vol. 92, pp. 268–282, 2016. [21] rezaee f.k., a. tayebi, "exergy destruction of forced convective (eg+al2o3) nanofluid through a duct with constant wall temperature in contrast to (ethylene glycol) fluid, journal of applied sciences vol. 10, no. 13, pp. 1279–1285, 2010. [22] sheikholeslami, m.; ellahi, r.; hassan, m.; soleimani, s. "a study of natural convection heat transfer in a nanofluid filled enclosure with elliptic inner cylinder". int. j. numer. methods heat fluid flow, vol. 24, pp. 1906–1927, 2014. [23] zamzamian a, nasseri s, oskouie, doosthoseini a, joneidi a, pazouki m. experimental investigation of forced convective heat transfer coefficient in nanofluids of al2o3/eg and cuo/eg in a double pipe and plate heat exchangers under turbulent flow. exp ther fluid sci ,vol. 35, pp. 495–502, 2011. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 96 table (1): thermophysical properties. property fluid phase (water) nanoparticle (cuo) cp (j/kg k) 4182 540 3 ) 997.1 6500 k (w/m k) 0.613 18 7 (m 2 /s) 1.47 57.45 table (2): mesh independent case. mesh no. mesh size (number of cells) heat transfer coefficient, h (w/m 2 .k) no. 1 12000 748.41 no. 2 24000 729.12 no. 3 36000 727.305 no.4 48000 727.031 figure (1): schematic diagram of the physical system. inlet outlet l = 1.2 m d = 4.75 mm m q'' = 5000 w/m 2 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 97 (a) re=500 (b) re=1300 (c) re=2100 figure (2): temperature contours map in the end of the pipe for cuo-water nano-fluid (d=29 nm, f=5%). al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 98 figure (3): heat transfer coefficient variation with reynolds number at x/d=150 for 29 nm cuo-water nano-fluid. figure (4): heat transfer coefficient for pure water and cuo-water with re=1700 at different axial distance. f = 1% f = 3% f = 5% f = 1% f = 3% f = 5% al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 99 figure (5): variation of nusselt number with reynolds number at x/d=150 for 29 nm nano-fluid. 99 figure (6): nusselt number variation with axial distance for pure water and cuo-water with re=1700 at different axial distance. f = 1% f = 3% f = 5% f = 1% f = 3% f = 5% al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 100 figure (7): dimensionless temperature profile along vertical distance at different axial locations (re=500 for pure water). figure (8): dimensionless temperature profile along vertical distance at different axial locations (re=500 & f=5%). al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 101 figure (9): temperature difference variation with axial distance for re=500 with various fluid concentration at y=4 mm. 101figure (10): comparison of experimental and numerical results for al2o3 nanofluid. f = 1% f = 5% al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 102 figure (11): parity plot comparing the prediction values and simulation results. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 283 using volume of fluid approach to simulate nanofluid flow ahmed abed al-kadhem majhool mechanical engineering department, college of engineering, al-qadissiya university ahmidkadhim@yahoo.com received 16 july 2014 accepted 18 september 2014 abstract a new implementation for the volume of fluid model with finite volume method is applied to simulate two-phase flow involving nano-particles. the model is used to investigate the laminar flow utilizing nanofluids in a lid-driven cavity. the fluid in the cavity is a water-based nanofluid containing cu, cuo or al2o3 nano-particles. the effects of adding extra phase (solid phase) and solid volume fraction for different nanofluids on hydrodynamic characteristics are investigated. the effective density and viscosity of nano-particles are calculated by chon and brinkman models, respectively. the cfd model is validated for laminar flow and the results showed good agreement with available numerical data. then the model is tested for liquid and nano-particles where the results indicate that the effects of solid volume fraction approximately depend strongly on the effective density sequentially for al2o3, cuo and cu. in addition the effective viscosity has less effect on the flow field. keywords: nanofluid, laminar, two-phase, finite volume method, cavity الملخص مشتمل على وجود طورين من المائع واحد هذي لمحاكاة تدفق ةمحدودطريقة الحجوم ال مع مائع حجم التطبيق جديد لنموذج ذات غطاء في تجويف مائع نانوي استخدامب الطباقي يستخدم هذا النموذج للتحقيق في تدفق االطوار حاوية على جزيئات نانوية. التي تحتوي على وحاوي على جزيئات نانوية في حاالت مختلفة وعبارة عن سائل )ماء( في التجويف هو لمائع الموجودا متحرك. الصلب حجم جزءكسر . تم دراسة تأثير إضافة مرحلة إضافية )المرحلة الصلبة( ونانوية جزيئاتك al2o3أو cuoالنحاس، تحسب الكثافة واللزوجة فيما يتعلق بالخصائص الهيدروديناميكيةالمختلفة على الخصائص الهيدروديناميكية. للجزيئات النانوية cfdمن قبل تشون وبرينكمان ، على التوالي. يتم التحقق من صحة نموذج على اساس استخدام نماذج فعالة من نانو جزيئات وأظهرت النتائج اتفاق جيد مع البيانات الرقمية المتاحة. ثم يتم اختبار نموذج لجزيئات النانو السائلة وحيث أظهرت طباقي لتدفق ال والنحاس. باإلضافة al2o3 ،cuoيعتمد بشدة على نحو متسلسل الكثافة فعال ل الصلب جزءالحجم كسر نتائج أن آثارال لزوجة فعالة لها تأثير أقل على مجال التدفق. mailto:ahmidkadhim@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 282 1. introduction over the last decade, liquids with unvarying suspended nanofluids (nano-particles) have been extensively investigated for improved thermal properties. there have been many researchers in literature that recorded in their work the enhancement of thermal conductivity for fluids with percentages of a solid volume fraction does not exceed 10\%. many attempts in the modeling field have been made to formulate appropriate effective approach. the single phase or two phases approach could be used for simulating laminar, turbulent and convective heat transfer with nanofluids maiga et al [1], roy et al [2] and khanafer et al [3]. the single phase approach is simpler and requires fewer computational time, which assumes that the fluid phase and particles are in thermal equilibrium and move with the similar velocity akbarinia and behzadmehr [4] and akbarinia [5]. in order to close the system by using suitable expressions which calculate the properties of single phase nanofluid which are become important and notable. moreover, the single phase approach has been implemented in different theoretical works of fluid flow and convective heat transfer with nanofluids, for example, talebi et al. [6], shahi et al [7] and sundar et al [8]. therefore the properties of nano-particles are not completely specified and there are not accurate formulas for predicting nanofluid mixture. the nanofluids were modeled by using single and two phase approach through a parametric study of thermal performance in a three dimensional transport equations have been used by tokit[9] to investigate the generality of nano-particle velocity equation. the conservation equations (continuity, momentum and energy) were solved by using finite volume method. in heat transfer field, oztop and abu-nada [10] discussed the natural convection in a rectangular cavity filled with a nanofluid containing cu, al2o3 and tio2 as nanoparticles. they concluded that the greatest value of heat transfer is obtained by using cu nanoparticles. generally speaking the predication of nanofluid using a single phase numerically is not coping the agreement with experimental results. so, this paper aims to simulate the nanofluid with a new method (volume of fluid) framework which is never used before as shown in the literatures. the method has been implemented in a cavity to study the nanofluid laminar behavior without heat transfer effect using. to do this, the eulerian-lagrangian approach of two-phase model is used. the eulerian method is used for the mass and momentum conservation equations for liquid phase while the lagrangian model is used for the solid phase. it should be pointed to that, this is the first paper implemented the two-phase nanofluid modeling in a cavity under laminar and ambient conditions. moreover, from the previous work of many researchers, they used different nano-material but without optimized for the selection of the best one. 2. governing equations the governing equations for fluid motion are the navier-stokes equations. the flow is assumed to be a steady, laminar and incompressible flow. when the density of a viscous fluid is constant, the equations are sufficient to model the flow in general form can be described in terms of the conservation of mass equation, or commonly known as the continuity equation. the continuity equation in divergence form can be written as: al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 283 where ρ, v, and are the density, velocity vector and gradient operator respectively. the conservation of momentum equation is derived using the newton’s second law applied to a fluid passing through an infinitesimal control volume. it is written in divergence form as: where µ, s and p are the fluid viscosity, the source term due to any external forces and the pressure gradient. 3. volume of fluid approach the volume of fluid approach can handle the modeling of two or more phases by solving a single set of transport equations and tracking the volume fraction of each of the fluids throughout the domain. in this case for a fluid – solid system, the vof method involves the construction of a new transport equation for the continuity and momentum equations for the indicator volume fraction, α to describe the evolution nano-fluid. therefore the equations can be written as: mathematically because the volume fraction α is unknown throughout the domain, an equation is needed for its computation. the continuity and momentum equations for the fluid can be used as a volume fraction to determine the fraction of the phase in the control volumes. the volume of fraction which is provided is not all used in the computations according to its definition below: •α= 0 : the cell is empty (full with fluid). • α = 1 : the cell is full (full with solid). • 0 <α < 1: the cell contains the solid and fluid. therefore the volume of fraction transport equation can take the form of where (p) and (f) are referring to the particle phase and liquid phase respectively. in the transport equation of the conservation of momentum, (4),vp is defined as the drift velocity for secondary phase k (i.e., the nano-particles in this work), and can be written as al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 283 the relative velocity (slip velocity) is denoted as the velocity of secondary phase (p) relative to the velocity of the primary phase (f) the relation between the drift velocity and the relative velocity becomes the drift velocity, calculated from equation (6) can be determined according to by manninen et al. [11] while the relative velocity is taken from schiller and naumann [12] is used to calculate the drag coefficient where (a) is the acceleration and can be determined from and (fdrag) is evaluated depending on the reynolds number value from the density of the nanofluid containing a dilute suspension of small rigid spherical particles is given by and the effect of viscosity at reference temperature is given by 4. the complete algorithm the navier stokes equations are solving using (simple) algorithm of patankar and spalding as cited in versteeg [13]. to discretize the governing equations for fluid flow, the cell-centered finite volume method is selected. in this algorithm the overall solution procedure is iterative and is based al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 283 on a pressure-correction equation is derived from the discretized equations for continuity and momentum. the discretized momentum equation for node (p0) can be written as where ( ) is the discrete gradient operator. the required mass flux correction is obtained from the velocity corrections, and substituting in the discretized continuity equation gives the pressure correction equation for cell (p0) as: where is obtained using equation (11) and finally, the linear system of equations can be cast in the form of: 5. problem definition the considered geometry of this work is depicted in figure 1. this geometry includes a square cavity with nano-particles of different materials as listed in table 1. the temperature of both liquid and nano-particles are kept at ambient temperature in order to investigate the effect driven velocity. the problem deals with a confined flow in a square enclosure. the flow is driven by the constant displacement of the upper wall where the tangential velocity is enforced. the description of the problem, configuration and the computational domain of the cavity is shown in figure 2.for the selected test case, the computational domain with three different grid resolutions are used in this study as shown below. all test cases are run with value of reynolds number 1000 to show the objective from this research. these are simulated and compared with benchmark results from ghia et al. [14]. the details of the grid and code validation will be discussed briefly in the next section. 6. code validation the validation of the proposed numerical solution is discussed in this section. the simulation results are compared with the numerical available results from the literature. in addition, because of the lack of experimental data for nanofluid flow in a steady laminar flow without heat transfer al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 287 effect. therefore for a single-phase fluid flow, the standard test case of a flow field within a two dimensional, steady -state, incompressible laminar flow is used to validate the solver. the lid which moves at a constant axial velocity drives the flow inside the cavity due to the transport of shear stress by the molecular viscosity. this problem has clearly defined in geometry and boundary conditions as shown in figure 3. in addition, the balance of convection and diffusion in the momentum equations connected with recirculating zones introduce a good material to makes this problem an excellent case for testing the multi-grid techniques. the simulation of the tested case starts from the motion of the lid (the upper wall), the velocity at the top boundary of the cavity is set at 1 m/sec. the enclosure cavity is a square in shape with unit dimensions in width and height. the four boundaries are viscous walls where a no-slip condition is implemented. the flow is identified by the reynolds number, which is defined by: where (ρ) is the density of the fluid, (ulid) is the velocity of the moving lid, (l) is the length and height of the cavity, and (µ) is the viscosity of the fluid. due the lack of experimental data for the lid driven cavity with the presence of nano-particles, the present numerical solution is also validated by the available numerical results published by ghia et al. [14]. figures 4 a and b show comparisons between the present study and the available numerical data. both axial and vertical velocity components expressed good agreement with referenced data. 7. results and discussions fluid driven cavity flow is solved for of nine computational cases are used to simulate the nanofluid flow configuration. first three cases of different volume of fraction values of [0.03, 0.05 and 0.1] and with three different reynolds number values of [100, 400 and 1000]. after extracting the results, one case will be adopted in this work where the liquid volume fraction is (0.1) and the reynolds number is (1000). physical properties of nano-particles and fluid at the base temperature 20 °c are listed in table 2. figure 5a shows the mid plane axial velocity component (u) is plotted for various nanofluid. the most nanofluid identical to the pure fluid is (al2o3), because of the density of the mixture is the approximately the closest one to the pure fluid (liquid water). it should be noted in this plot that the region near the upper wall of the cavity the forward motion of fluid is dominating due to shear action and all nanofluids are showed same behavior. beyond this region the nanofluids flow in rearward direction. figure 5b shows the mid plane vertical velocity component (v) where the value of solid volume fraction is (0.1). it is obvious from this figure that distribution of velocity is not symmetric with respect to the center of the cavity as in case of using air. it can be observed that the higher values of vertical velocity component are found near the upper wall which is matching the standard air case and then decrease gradually towards the bottom wall. again the (al2o3) shows a good agreement with liquid trend. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 288 figure 6 shows the stream line contour plots of two dimensional case of the considered problem for reynolds number equals to 1000. in general it is found that the recirculation zone due to shearing action of upper velocity is clearly noticeable. in all cases which are identical with conventional wall shear cavity flow, it is found that one primary recirculation eddies regime is formed at the upper right corner of the cavity. the strength of these eddies for (h2o) and (al2o3) are approximately the same in size and (cu) and (cuo) are also. figure 7 can summarized all the investigation which is discussed above. the contour plots expressed the velocity magnitude for the liquid water and the nano-particles of different materials. in this work will be gone farther, where in figure 8a presents the term the divergence of velocity extracted along the middle of the centerline of the cavity. nevertheless, it can be seen that due to the mass of the nano-particles in the corner is nearly conserved. the somewhat non-zero value of the divergence of velocity is probably because of the particle accumulation effect in the corner. in figure 8b presents the , divergence of velocity extracted along the middle of the centerline of the cavity. it can be seen that the same trend for the nano-particles but due to the heavier of the particles the divergence of the velocity is increased. 8. conclusions laminar flow in a lid-driven cavity utilizing nanofluid is simulated by volume of fluid model (vof). this paper presents a new numerical study for the nanofluid which is implemented in a cfd code to simulate the nano-particles in laminar flow under ambient condition without the effect of heat transfer in a cavity. it treats the nanofluid as a suspended phase inside the liquid. the conclusions from the numerical analysis performed in this study are summarized as follows: 1the two-phase model is performed well with the advanced finite volume method. 2 it is interesting to study the laminar flow without heat transfer effect. 3the work object to optimize the flow of nano-particle under the room conditions to select the lower density material. 9. references [1] s.e.maiga, c.t. nguyen, n. galanis, and g. roy. heat transfer behaviors of nanofluids in a uniformly heated tube. super lattices microstructure, 35 (36), 543–557, 2004. [2] g. roy, c.t. nguyen and p.-r. lajoie. numerical investigation of laminar flow and heat transfer in a radial flow cooling system with the use of nanofluids. superlattices microstruct.35(36), 497–511,2004. [3] k. khanafer,k. vafai and m. lightstone. buoyancy driven heat transfer enhancement in a two dimensional enclosure utilizing nanofluids. international journal of heat and mass transfer 46, 3639–3653,2003. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 283 [4] a. akbarinia and a. behzadmehr. numerical study of laminar mixed convection of a nanofluid in horizontal curved tubes. journal of applied thermal engineering. 27, 1327– 1337,2007. [5] a. akbarinia. impacts of nanofluid flow on skin friction factor and nusselt number in curved tubes with constant mass flow. international journal of heat and fluid flow 29 (1),229–241, 2008. [6] f. talebi, a.h. mahmoudi and m. shahi. numerical study of mixed convection flows in a square lid-driven cavity utilizing nanofluid. international communication of heat and mass transfer. 37, 79–90,2010. [7] m. shahi, a.h. mahmoudi and f. talebi. numerical study of mixed convective cooling in a square cavity ventilated and partially heated from the below utilizing nanofluid. international communication of heat and mass transfer. 37, 201– 213, 2010. [8] l.s. sundar, k.v. sharma and s.parveen. heat transfer and friction factor analysis in a circular tube with al2o3 nanofluid by using computational fluid dynamics. international journal of nanoparticles. 2 (16), 191–199, 2009. [9] e. mat tokit, m. z. yusoff and h. mohammed. investigation on nanoparticle velocity in two phase approach, international journal of mechanical, industrial science and engineering vol:7 no:10, 136-142, 2013. [10] h.f. oztop and e.abu-nada. numerical study of natural convection in partially heated rectangular enclosures filled with nanofluids, international journal of heat and fluid flow, 29,1326-1336,2008. [11] m. manninen, v. taivassalo, and s. kallio. on the mixture model for multiphase flow. techical report. 288, vtt technical research centre of finland, 1996. [12] l. schiller and a. naumann. a drag coefficient correlation. zeitschrift des vereins deutscher ingenieure.77, 318–320, 1935. [13] h. k. versteeg and w. malalasekera. an introduction to computational fluid dynamics. pearson, second edition, 2006. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 233 [14] u. ghia, k.n. ghia and c.t. shin. high-resolutions for incompressible flow using the navier stokes equations and a multigrid method. journal of computational physics. 48, 387– 411,1982. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 233 figure 1: description of the problem. figure 2: computational domain. figure 3: description of boundary conditions of the problem. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 233 figure 4: comparisons with the referenced data. (a) (b) figure 5: a-variation of axial velocity component at x=0.5 m with vertical distance. b-variation of vertical velocity component at y=0.5 m with axial distance. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 232 figure 6: streamlines for liquid water and different nano-particles. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 233 figure 7: velocity magnitude for liquid water and different nano-particles. (a) (b) figure 8: a-variation of axial velocity divergence at x=0.5 m with vertical distance. b-variation of vertical velocity divergence at y=0.5 m with axial distance.} template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 244 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. three-dimensional analysis of girder crosssection shapes effects on static properties of bridges models ali fadhil naser al-furat al-awsat technical university/ al-mussaib technical college/ building and construction engineering department. email: ali_hu73@yahoo.com received on 18 january 2016 accepted on 9 august 2017 abstract: the aim of this study is to select the suitable shape of girder cross section that is used in the design of bridges structure, and to evaluate the effect of cross section shape of bridges girders on the static properties such as vertical displacement, vertical shear force, bending moment, tension stress and compressive stresses. ten bridges models using different types and shapes of girders were used to study the effect of girder cross section shape in the construction of bridges by adopting static analysis. the results of finite element analysis showed that the bridges models of separated concrete deck over girders have higher value of vertical displacement, positive bending moment, and tensile stress. these models are not suitable for design of bridges that subjected to higher traffic loads because of these bridges structures will not have enough stiffness and higher carrying capacity. therefore, they will fail under heavy traffic loads. these models include flat slab bridge model, t-girder bridge model, i-girder bridge model, and steel i-girder bridge model. most box girders bridge models appeared the lower values of vertical displacement, positive bending moment, and tensile stress. therefore, these models will have enough stiffness and carrying capacity and they will be more elasticity from others models. this study recommended that using the box girders bridges models in the construction of new bridges structure that have high traffic loads. keywords: bridge, moment, cross-section shape, static, stress, vertical displacement 1. introduction bridges are structures provided that passageway over a barrier without closing the way underneath. the necessary passageway may be for highways, pedestrians, railways, and waterways such as rivers. therefore, bridges are important part of the transportation system. the volumes and the weights of the vehicles traffic carried by the transportation system can be controlled by the bridges capacity. generally, bridge structure consists of concrete deck, girders, bearings, cap beam, piers, abutments, and foundation. (meshrama and ramtekeb, 2015, mary et al, 2012, tdt, 2001) prestressed concrete consists of concrete material, reinforced steel, and prestressed tendons that is introduced the stresses to concrete to the suitable limit. there are two types of prestressing, pre-tension and mailto:ali_hu73@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 245 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. post-tension. the main advantages of prestressed concrete structure is delaying cracks, saving materials, reduction of vertical deflection, protraction of steel from corrosion, increasing the durability, has higher stiffness, increasing the shear capacity, modifying the resilience of structure under dynamic and fatigue loading. after appearing prestressed concrete, it has been widely and increasingly used in long span structures such as bridges with different type of girders depending on the shape of girder such as box girders (different types according shape), t-girder, i-girder, and i-steel girder with prestressed concrete deck. (concrete construction, 2016, suraj, 2006) recently, prestressed concrete box girders are widely used in the construction of freeways and bridge structures due to their structural efficiency, good stability, serviceability, construction economy and pleasing aesthetics. however, for analysis and design, box girder bridges are very complex due to its three dimensional behaviors that consist of torsion, distortion and bending in longitudinal and transverse directions. according to the method of construction, the use, and cross section shapes, box girders can be erected as single cell, double cell or multi-cell, rectangular, trapezoidal and circular. the box girder web can be classified as vertical, inclined, and curved which help to reduce the width of the bottom flange. (laxmi, 2013, negrao and simoes, 1999) the using of prestressed concrete decks over different types of precast girders such as t-girder, igirder, and i-steel girder are commonly used for bridges construction. the spans length of bridges ranges between 25m and 450m. therefore, it can provide economic, durable and aesthetic solutions in most situations where bridges are needed. (nigel, 2003) the main objective of structural analysis is to assess the static responses of a structure and to find the distribution of internal forces system such as vertical displacement, tension and compressive stresses. depending on the different applied loads, a linear elastic model is assumed in the structural analysis. the finite element method (fem) is a suitable implement to solve differential equations for the structural engineering applications. (mattias, 2012, csi, 2006) static analysis of bridge structure is very important type of analysis. the different types of loads (deck load, prestressed tendons load, temperature load, and static traffic load (vehicle load), are applied without dynamical influences (without moving of vehicles), while, dynamic analysis consists of three types of analysis ( without moving load, with tested vehicles load, and with all traffic loads types (service loads)) .(csi, 2010, meshrama and ramtekeb, 2015) pindado et al, 2005 used experimental analysis by testing different types of box girder shapes of bridge cross-sections to analyze the yawing moment that was acted on the box-girder deck of reinforced concrete bridges built by using the balanced cantilever method during the erection stage. the results of experimental analysis showed that the coefficient of yawing moment was decreased when the bridge decks become streamlined. when the bridge deck length is nearly twice the deck width, the coefficient of yawing moment was reached the maximum value. yuh et al (2005) investigated the effect of deck dimensions and approaching turbulence on the flutter and buffeting behavior of cable-supported bridges by using wind tunnel section model test. they used closed box girder model and plate girder model in their study. the results of analysis showed that the width-to-depth ratio (b/h) of bridge deck plays a significant function in bridge aerodynamics. the bridge stability was improved by increasing the width-to-depth ratio (b/h). chirag and kumar, 2014 explained the effect of changing the basic shape of bridge cross section girder on the stability of the bridge structure by using different lengths of the over-hanging beam section and increasing the thickness of the joints. according to the results of analysis, they found that the increasing in thickness at the fixed end of the cantilever beam leads to increase the thickness at the bottom most portion of the box structure and sloping edges. it provided more thickness at the fixed portions and also it reduced the stress acting on the entire span of the beam. the useful of this state is to reduce the bending moment acting at the fixed end and the beam becomes more stable. tiger and khadiranaikar, 2015 studied the effect of box girder shape on the static bending moment, shear force and vertical deflection for two models of box girder. the first model used four-cell rectangular box girder and the second model used four-cell trapezoidal box girder. they found that the vertical displacement al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 246 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. of rectangular box girder is increased by 30% compared with trapezoidal box girder for combined load case (dl+ll+prestress). shear force was increased by 11% in rectangular girder compare with trapezoidal box girder in combined load case. the shear stresses are 18% more in trapezoidal box girder because of the area is reduced in trapezoidal section but the stresses are still within allowable limit. the aim of this study is to optimize the suitable shape of girder cross section that is using in the design of bridge structure, and to evaluate the effect of cross section shape of prestressed concrete bridge girders on the static parameters such as vertical displacement, vertical shear force, bending moment, tension stress and compressive stresses. 2. bridges models of finite element analysis ten bridges models are adopted in this study depending on the shape of bridges girders cross section. the spans lengths of bridges models are same and the bridges models are designed to have four spans (15m+20m+20m+15m). the width of cross section for each model is 10m and each bridge model has two lanes. the input data in the analysis of bridges models, such as dimensions of bridge structure (width and height of cross section), traffic loads, prestressed load, and temperature load, are selected to be same for all models because of the results of analysis will be compared for all models to optimize the suitable shape of girder cross section that gives the best results. the substructure components such as abutments, bearings, piers caps, and piers are same for all models. the connection between abutments and girders is using condition of girder bottom only and foundation spring. the piers caps is rectangular shape (1.22m*1.525m) with length is 9.15m. the pier shape is circular with radius is 0.75m. the bridges models include t-girders shape model (simply supported bridge), i-girder shape model (simply supported bridge), flat slab shape model (continuous bridge), steel i-girder shape (simply supported bridge), box girder with external web clipped shape model (continuous bridge), box girder with external web curved shape model (continuous bridge), box girder with external web vertical shape model (continuous bridge), box girder with external web maximum sloped shape model (continuous bridge), aashto-pci-asbi standard box girder shape model (continuous bridge), and u-box girder shape model. finite element analysis is used to analyze the bridges model by adopting static using sap 2000 ver. 14.2. figure 1. shows the bridges models. (a) (b) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 247 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (c) (d) (e) (f) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 248 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (g) (h) (i) (j) figure (1): the bridges models: (a) t-girders shape model, (b) i-girder shape model (precast), (c) flat slab shape model, (d) steel i-girder shape model, (e) box girder with external web clipped shape model, (f) box girder with external web curved shape model, (g) box girder with external web vertical shape model, (h) box girder with external web maximum sloped shape model, and (i) aashto-pci-asbi standard box girder shape model, (j) u-box girder model al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 249 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. properties of materials and loads different types of materials are used for modeling analysis. these types include concrete, steel rebar reinforced, steel tendons, and steel girder. table 1 shows the properties of concrete material. table 2 shows the properties of steel tendons. table 3 shows the properties of steel rebar. table 4 shows the properties of steel girder. the loads of bridges models are applied on the structure are same and consist of dead load of bridge structure (weight of superstructure + weight of substructure), deck load, pedestrian load, pavement load, prestressed load, temperature load, and live load (traffic load). for live load, vehicle type hs20-44 is used in the analysis. table (1): properties of concrete material properties of concrete material value concrete grade c 40 weight/volume 23.5631 kn/m 3 density 2.40 kg/m 3 modulus of elasticity (e) 32500000 kn/m 2 shear modulus (g) 13541667 kn/m 2 factor of thermal expansion (a) 9.90*10 -6 poisson ratio (µ) 0.2 compressive strength of concrete (f ’ c) 40000 kn/m 2 directional symmetry type isotropic ultimate unconfined strain capacity 5*10-3 strain at unconfined compressive 2.46*10 -3 table (2): properties of steel tendons properties of steel tendons value steel grade a416gr270 weight/volume 76.9729 kn/m 3 density 7.849kg/m 3 modulus of elasticity (e) 1.965*10 8 kn/m 2 minimum yield stress (fy) 1689905.2 kn/m 2 factor of thermal expansion (a) 1.17*10 -5 minimum tensile stress (fu) 1861584.6 kn/m 2 directional symmetry type uniaxial al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 250 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (3): properties of steel rebar properties of steel rebar value steel grade a615gr60 weight/volume 76.9729 kn/m 3 density 7.849kg/m 3 modulus of elasticity (e) 1.999*10 8 kn/m 2 minimum yield stress (fy) 413685.5 kn/m 2 factor of thermal expansion (a) 1.17*10 -5 minimum tensile stress (fu) 620528.2 kn/m 2 expected yield stress (fy) 455054 kn/m 2 expected tensile stress (fu) 682581 kn/m 2 directional symmetry type uniaxial table (4): properties of steel girder properties of steel girder value steel grade a992fy50 wight/volume 76.9729 kn/m 3 density 7.849kg/m 3 modulus of elasticity (e) 1.999*10 8 kn/m 2 minimum yield stress (fy) 344737.9 kn/m 2 poisson ratio (µ) 0.3 factor of thermal expansion (a) 1.17*10 -5 minimum tensile stress (fu) 448159.3 kn/m 2 effective yield stress (fy) 379211.7 kn/m 2 effective tensile stress (fu) 492975.2 kn/m 2 shear modulus (g) 76903069 kn/m 2 directional symmetry type uniaxial 4. finite element static analysis there are four parameters as an output data of static analysis for ten bridges models have different shapes of girders cross sections. these parameters include vertical displacement, vertical shear force, bending moment, tension and compressive stresses. the shell element model is used in three-dimensional structures analysis of this study. the shell element is one type of area object and it is a three or four nodes formulation that combines separate membrane and plate-bending behavior. in this study. four nodes formulation elements are used in static analysis. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 251 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.1. live load due to vehicles load analysis vehicles load analysis are performed by using vehicle type as hs 20-44 and load case as linear static. table 5 lists the results of static parameters due to vehicles load. 4.2. service loads analysis the applied service load on the bridges models include the combination of structure dead load, deck load, prestressed tendons load, temperature load, and traffic load (vehicle load). table 6 lists the results of static parameters due to service loads. figure 2 to figure 8 shows the comparison results of static analysis of bridges models. table (5): results of static parameters due to vehicles load model no. model shape vertical displacement (mm) bending moment (kn.m) shear force (kn) stress (mpa) max + min max + min max + min 1 t-girders 3 5183 -2338 1609 -1609 3.57 -10.45 2 i-girder 8 1640 -2267 839.7 -839.7 4.37 -8.24 3 flat slab 16 2417 -4664 1384 -1384 5.65 -8.70 4 steel i-girder 3 2143 -4294 1385 -1338 6.2 -16.65 5 b.g.external web clipped 2 3929 -7659 2239 -2239 1.44 -2 6 b.g.external web curved 2 4018 -7796 2282 -2282 1.46 -1.91 7 b.g.external web vertical 2 4134 -7947 2323 -2323 1.45 -1.88 8 b.g.external web max. sloped 2 3378 -6836 1985 -1985 1.44 -2.64 9 aashto-pci-asbi standard 2 2438 -4586 1358 -1358 1.06 -1.98 10 u-box girder 6 328 -679 325 -325 3.10 -3.98 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 252 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (6): the results of static parameters due to service load model no. model shape vertical displaceme nt (mm) bending moment (kn.m) shear force (kn) stress (mpa) max + min max + min max + min 1 t-girders 12 77908 -42476 20392 -28228 4.52 -8.20 2 i-girder 20 15088 -9822 5488 -5325 6.30 -15.8 3 flat slab 50 13033 -88372 3712 -3807 8.60 -6.70 4 steel i-girder 23 54989 -28229 10419 -10580 5.47 -9.85 5 b.g.external web clipped 6 39982 -6715 10367 -7512 5.95 -12.07 6 b.g.external web curved 7 26153 -5777 6298 -6138 3.80 -7.78 7 b.g.external web vertical 6 42408 -2568 9875 -7668 5.67 -12.07 8 b.g.external web max. sloped 8 34321 -1264 5754 -6603 9.91 -10.71 9 aashto-pciasbi standard 8 18749 -3002 3856 -3967 4.10 -8.04 10 u-box girder 25 14419 -16332 5568 -5568 5.12 -10.7 figure (2): vertical displacement due to vehicle load al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 253 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3): positive and negative bending moment due to vehicle load figure (4): positive and negative bending moment due to service load al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 254 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (5): shear force due to vehicle load figure (6): shear force due to service load al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 255 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (7): stresses due to vehicle load figure (8): stresses due to service load al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 256 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. discussion of static analysis results according to table (5), the results of vehicle load show that the maximum vertical displacement is 16 mm within flat slab bridge model and the minimum vertical displacement is 2mm within box girders with different external webs shape. therefore, the box girders models are suitable to carry vehicle loads. for bending moment, t-girder bridge model appears higher positive bending moment which is equal to 5183 kn.m and box girder with external web vertical bridge model has the higher value of negative bending moment and vertical shear force which that equal to 7947 kn.m and 2323 kn respectively. flat slab bridge model gives the maximum value of tensile stress and it equal to 5.65 mpa. therefore, the cracks will appear on this model. the minimum value of tensile stress appears within aashto-pci-asbi standard box girder bridge model which is equal to 1.06 mpa. the higher value of compressive stress is -16.65mpa within steel i-girder bridge model. for service loads analysis results which is listed in table (6), the higher value of vertical displacement is appeared within flat slab bridge model which is 50mm, while the minimum value of vertical displacement is found within box girder with external web clipped bridge model and box girder with external web vertical bridge model which is 6mm. t-girder shape bridge model has maximum value of positive and negative bending moments, and positive and negative shear forces which is equal to 77908 kn.m, -42476 kn.m, 20392kn, and -28228 kn respectively. the maximum tensile stress and compressive stress appears in the i-girder bridge model which is equal to 6.5mpa and15.8 mpa respectively and the minimum tensile stress and compressive stress is equal to 3.80 mpa and 6.70 mpa within box girder with external web curved shape model and flat slab shape model respectively. according to above results, the models have higher value of vertical displacement, positive bending moment, tensile stress are not suitable to design of bridges that subjected to higher traffic loads because of these bridges structures will not have enough stiffness and carrying capacity. therefore, they will fail under heavy traffic loads. these models include flat slab bridge model, t-girder bridge model, i-girder bridge model, and steel i-girder bridge model. most box girders bridge models appears the lower values of vertical displacement, positive bending moment, tensile stress. therefore, these models will have enough stiffness and carrying capacity and they will be more elasticity from others models. this study recommended that using the box girders bridges models in the construction of new bridges structure that have high traffic loads 6. conclusions and recommandation the conclusion of this study includes: 1. the effect of girder cross section shape in the construction of bridges is studied by adopting finite element static analysis for ten bridges models using different types and shapes of girders. 2. according to output data of static analysis, seven parameters are used. these parameters include vertical displacement, vertical shear force, bending moment, tension and compressive stresses. 3. for vehicle load analysis, the results of finite element analysis show that the flat slab bridge model has the maximum vertical displacement which is 16 mm and the minimum vertical displacement is 2mm within box girders with different external webs shape. therefore, the box girders models are suitable to carry vehicle loads. for service load, the higher value of vertical displacement is appeared within flat slab bridge model which is 50mm, while the minimum value of vertical displacement is found within box girder with external web clipped bridge model and box girder with external web vertical bridge model which is 6mm. 4. according to bending moment analysis, t-girder shape bridge model has maximum value of positive and negative bending moments, and positive and negative shear forces which is equal to 77908 kn.m, -42476 kn.m, 20392kn, and -28228 kn respectively. 5. the results of stress analysis show that the higher value of tensile stress and compressive stress appears in the i-girder bridge model which is equal to 6.5mpa and 15.8 mpa respectively. 6. the minimum tensile stress and compressive stress is equal to 3.80 mpa and 6.70 mpa within box girder with external web curved shape model and flat slab shape model respectively. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 257 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 7. some models appears maximum values of vertical displacement, positive bending moment, tensile stress. these models include flat slab bridge model, t-girder bridge model, i-girder bridge model, and steel i-girder bridge model. these models are not suitable to resist heavy traffic loads because of these bridges structures will not have enough stiffness and carrying capacity. 8. most box girders bridge models appears the lower values of vertical displacement, positive bending moment, tensile stress. therefore, these models will have enough stiffness and carrying capacity and they will be more elasticity from others models. this study recommended that using the box girders bridges models in the construction of new bridges structure that have high traffic loads. 9. the future recommendation is using dynamic analysis to study the effects of girder cross section shape on the dynamic parameters. references 1. chirag, g., kumar, m., study of basic design of precast segmental box girder, international journal of civil engineering,vol. 3, issue 3, 2014, pp: 103-112. 2. concrete construction, 2016, usa, http://www.concreteconstruction.net/. 3. csi computer and structures inc., basic analysis reference manual of sap2000: linear and non-linear, static and dynamic, analysis and design of three-dimensional structures, berkeley, california, usa, 2006, pp: 5-87. 4. csi computer &structures inc, introduction to sap2000/bridge, berkeley, california, usa, 2010. 5. laxmi, p., study on parametric behavior of single cell box girder under different radius of curvature, master thesis, department of civil engineering, national institute of technology rourkela odisha, india, 2013. 6. mary, d., john, b., anagha, s., continuous prestressed concrete girder bridges, vol. 1: literature review and preliminary designs, project performed in cooperation with the texas department of transportation and the federal highway administration, 2012. 7. mattias, g., structural analysis and design of concrete bridges, master thesis, department of civil and environmental engineering division of structural engineering concrete structures, chalmers university of technology, sweden, 2012. 8. meshrama, s. ramtekeb, p., effect of vehicle velocity on the dynamic amplification factor for a simply supported t-beam bridge, international journal of innovative and emerging research in engineering, vol. 2, issue 5, 2015, pp: 102-108. 9. negrao, j., simoes, l., shape and sizing optimization of box-girder decks of cable-stayed bridges, computer aided optimum design of structures, transactions on the built environment vol. 37, 1999, wit press, pp:323-332 10.nigel, r., prestressed concrete bridges: design and construction, 2003, http://www.icevirtuallibrary.com/doi/book/10.1680/pcbdac.32231. 11. pindado, s., meseguer, j., franchini, s., the influence of the section shape of box-girder decks on the steady aerodynamic yawing moment of double cantilever bridges under construction, journal of wind engineering and industrial aerodynamics, vol.93, issue 7, 2005, pp: 547–555. 12. suraj, p., ram, k., sharma, b., prestressed concrete beams under fatigue loading, advances in bridge engineering, 2006, pp: 433-443. 13. texas department of transportation (tdt), bridge detailing manual, 2001, txdot 8. 14. tiger, v., khadiranaikar, r., study on effect of shape in psc box girder bridge, international journal for scientific research & development| vol. 3, issue 06, 2015, pp:412-416. http://www.concreteconstruction.net/ al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 258 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 15. yuh, l., chii, c., jong, c., tsang, l., kuo, w., effects of deck shape and oncoming turbulence on bridge aerodynamics, tamkang journal of science and engineering, vol. 8, issue 1, 2005, pp. 43-56. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 308 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. experimental investigation for the behavior of hollow core concrete slab reinforced with hybrid reinforcement labeeb s. al-yassri university of al-qadisiah, iraq email: labeeb.husein@qu.edu.iq ammar y. ali university of babylon, iraq email: eng.ammar.yaser@uobabylon.edu.iq mohammed m. al-khafaji university of babylon, iraq email: eng.mohammed.mansour@uobabylon.edu.iq received on 27 march 2017 accepted on 9 august 2017 abstract: this paper provides an experimental study to investigate the effect of hybrid reinforcement on the behavior of hollow core slab casted with nsc. experimental results showed that using of hybrid reinforcement (cfrp and steel bars) as internal reinforcement give better results of ductility compared with hcs reinforced with cfrp bars only. on the other hand, using of cfrp bars as an internal reinforcement have slightly effect on the shear strength capacity of hollow core slab. on the other hand, cfrp reinforcement lead to decrease the stiffness of slab at post cracking stage; therefore, deflection will increase at the same load after cracking. keywords: hollow core slab, cfrp bars, hybrid reinforcement, shear strength capacity, cracking load. 1.introduction during the last two decades of the twenty century, the use of frp forms in construction of r.c structures has been developed and it covers the new construction and rehabilitation of existing structures owing to their superior mechanical properties as mentioned previously. the number of projects utilizing the frp forms to strengthening the structures around the world was increased as a result for developing of design guidelines and methods. however, in addition to its higher cost, the greater strength of the frp is inducing fragile behavior at or close to failure. this fragile behavior is not recommended for structures in seismic regions [1]. some studies which concerned in experimental investigations and in site applications of frp forms for r.c. structures can be found in various publications [2-3]. practical applications of frp rebars were good reviewed in [4].composite concrete slabs resulting from using concrete of one type of strength (either normal compressive strength concrete nsc or high compressive strength concrete hsc) in addition to reinforcement of type steel, polymer or any other types of frp (artificial or natural) fukuyama, 2000 [1]. mailto:labeeb.husein@qu.edu.iq mailto:eng.ammar.yaser@uobabylon.edu.iq mailto:eng.mohammed.mansour@uobabylon.edu.iq al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 309 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. codrut. et al., 2010 [5] prepared and test four specimens of pphcs two of them were strengthened by using cfrp sheet glued at the tension face to increase their flexural capacity. the experimental tests have proven that the failure of the slab was caused by shear efforts, and that the superior flexural capacity gained by strengthening of the slab was not harnessed at all. nonetheless, the cfrp had an important influence in keeping the cracks from premature opening and further widening. nanni et al.1994 [6, 7] conducted a tests on bars of combination of a steel core covered by aramid fiber submerged in an epoxy matrix. test results showed a bilinear behavior(stress–strain) for this type of hybrid reinforcement. they also noticed that such form of rebar had limited flexibility to the steel distribution within section when they were used in the rc members. bakis et al, 1996 [8] concluded that the material with high modulus could be dispersed within the entire area (cross sectional area of composite member) to maximize the bilinear (ductile)behavior. distribution of material of stiffer rebar will be more uniform in cross section when using two or more types of rebars in that section. using frp rebars in over rc sections to increase the ductility appeared to be an attractive solution. fiber reinforced polymer frp has become a practical active material for replacing traditional steel rebar which used as reinforcement construction of r.c. structures [9]. however, the brittle behavior of fiberreinforced polymer reduces the ductility of frpr.c. members greatly. so as to improve the flexural ductility of frp r.c. members, it is proposed that the longitudinal reinforcement should be included on the steel rebars to form a hybrid reinforcement. therefore, in this investigation studies the effect of cfrp bars on behavior of hcs in different forms of reinforcement. 2.experimental work current experimental works include a series of tests conducted on several materials of building construction, control specimens such as (cubes, prisms and cylinders), and the slab specimens. the tested slabs were fabricated from normal strength r.c. the main objective of this paper is to investigate the effect of replacement of traditional steel bars by cfrp bars using different percentage of replacement (0%, 50% and 100%) to reinforcing hollow core model for flexural. 2.1. specimens description the experimental program consisted of testing four reinforced concrete slab models. all tested slabs were one way slabs with same dimensions of length (1200 mm), span (1100 mm c/c of supports), total width (600mm), overall depth (100mm) and clear cover of (20 mm).all hollow core slab tested here have the same cross section details of reinforcement and voiding ratio 26%. all slabs were reinforced with 6 mm deformed steel rebars and/or cfrp rebars in tension zone with tensile reinforcement ration equal to 0.5%. this ratio taken larger than minimum and lower than maximum ratios specified by aci 318m-11 [10]. full details of hollow core slabs are given in table 1 and figure 1. all specimens of this study was tested under two line loads as shown in figure 1. table 1. details of tested slabs sample code description no. voids ratio% concrete type flexural reinforcement steel cfrp os.h26.hr0.hc0 26 nsc 100% 0% 1 os.h26.hr50.hc0 26 nsc 50% 50% 1 os.h26.hr100.hc0 26 nsc 0% 100% 1 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 310 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 1. dimensions details of tested slabs 2.2. materails all specimens were produced from using of normal strength concrete nsc. two types of reinforcing bars were used steel and/or cfrp bars. 2.2.1. cement ordinary portland cement manufactured in iraq named al-douh was used throughout this investigation. properties of this cement were agree with the limits of iraqi specifications (i.q.s.5/1984) [11] of portland cement.. 2.2.1. fine aggregate sand (nature fine aggregate) used in this research were from al-ukhaidher region in iraq. particles grading of this aggregate obtained from results of laboratory test were agree with the iraqi (i.q.s.45/1984) [12] and (astm c33) [13] specifications. 2.2.2. coarse aggregate maximum size of 10 mm for the coarse aggregate were selected to use in this research type crushed to ensure complete filling and consolidation around the holes. it was brought from al-nibaey region. the properties of this gravel were agree with the limits of iraqi specifications (i.q.s. 45/1984) [11]. 2.2.3. mixing and curing water clean tap water of al-hilla, babylon, was used for wishing the aggregates, mixing and for curing all the specimens. 2.2.4. steel bar tensile test of steel reinforcement was carried out on (ø 6mm) hot rolled, deformed, mild steel bars employed as tension reinforcement for both, flexure and shear. table 2 gives the results of tensile test for bar (6 mm). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 311 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 2. physical properties of steel rebar weight (kg/m) nominal diameter (mm) measured diameter (mm) yield stress (mpa) ultimate strength (mpa) 0.229 6 5.91 556 741 2.2.5. cfrp bars carbon fiber reinforced polymer cfrp rebars used in this study to reinforced hcs spesimens. the 6 mm diameter cfrp rebar used here was aslan 201. the aslan 201 cfrp rebar physical properties for rebar of nominal diameter 6 mm listed in table 3. the test results of this type of frp used here were provided by the manufacturer. figure 2 illustrate the typical stress strain relation ship for the behavior of cfrp rebars as suggested by hughes brothers [14]. table 3. physical properties of cfrp bar reinforcement physical properties result limit of astm d7205 (105) average tensile strength (mpa) 2704 ≥ 2068 average modulus of elasticity (gpa) 163 ≥ 124 ultimate strain 0.017 0.017 weight (kg/m) 0.0557 figure 2. stress-strain curve of cfrp bars [14] 2.3. mix proportions mixture of normal strength concrete used in this study was designed in accordance with british standard bs 5328 [15] with nominal 28-day target compressive strength of (25mpa). it was found that the selected mixture produced good workability and homogeneous mixing of the concrete without separation. it was found that the selected mixture (table 4) produced good workability and homogeneous mixing of the concrete without separation. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 312 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 4. trial mixes for nsc and hsc selected mix proportions cement (kg/m 3 ) 310 silica fume (kg/m 3 ) n/a sand (kg/m 3 ) 700 gravel (kg/m 3 ) 1150 sp. (l/m3) n/a sbr (l/m3) n/a water (l./m3) 139.5 w/c 0.45 f`c (28 day) mpa 27.11 3. experimental results the experimental results of the tested slabs were compared to study the effect of using hybrid reinforcement concept on the structural behavior of the hcs such as ultimate and cracking loads, ductility, width of crack and the mode of failure. 3.1. cracking and ultimate loads and failure mode table 5 summarizes the experimental results of tested hcs specimens. these results including, first cracking load of flexural and shear cracks and their percentages with respect to the ultimate load, ultimate load and mode of failure of specimens also reported. 3.1.1. control specimen os.h26.hr0.hc0 this control slab specimen was made from nsc for overall its section that voided by eight cores of diameter 50 mm with about 26% voiding ratio, which regard as reference (control) specimen for comparison with other specimens. the first visible crack observed within maximum moment region of the tension face of slab (flexural cracks) at lower load of (21 kn) (i.e. 26.7% of ultimate load). the first visible diagonal shear cracks appeared at (35 kn) (i.e. 44.5 % of ultimate load) within shear span. more flexural cracks and shear flexural cracks formed later at constant moment region with increasing of applied load and the inclined cracks became wider and propagate rapidly. with increasing of load, major diagonal shear crack opened more and sudden flexural diagonal shear failure occur at load of about (78.7 kn) as shown in plate 1. figure 3 illustrates load deflection response for this control hcs. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 313 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. plate 1. mode of failure and cracks pattern of specimen os.h26.hr0.hc0 figure 3. load deflection response of os.h26.hr0.hc0 specimen 3.1.2. specimen os.h26.hr50.hc0 this slab specimen was fabricated with normal strength concrete and reinforced with hybrid reinforcement (50% cfrp bars and 50% steel bars) as mentioned in previous chapter. during the testing procedure of this specimen, first visible crack were observed at load (21.5) (26.2% of ultimate load) at the tension face of slab within constant moment region. several cracks were formed with increasing of applied loading. diagonal cracks were observed within shear span region at load about (36 kn). major diagonal crack propagated rapidly with advance stages of loading until shear failure occur at load (82 kn) as shown in plate 2. figure 4 illustrates load deflection response of this slab specimen. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 314 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. plate 2. mode of failure and cracks pattern of specimen os.h26.hr50.hc0 figure 4. load deflection response of os.h26.hr50.hc0 specimen 3.1.3. specimen os.h26.hr100.hc0 load deflection curve and cracks pattern of this specimen are shown in figure 5 and plate 3 that fabricated with normal strength concrete and reinforced by cfrp bars. at first, early crack initiated at tension face of slab within the constant moment region at load about (20 kn) (24.1% of ultimate load). comparing with control (os.h26.hr0.hc0) specimen, cracking load decreased by small percentage about 4.7% which can be neglected. hence, it is obvious that the cracking load mainly depending on the moment of gross sectional area of concrete (uncracked section) about centroidal axis. as the load increased, several cracks formed within region of max constant moment also flexural shear and shear cracks within shear span observed at load (45 kn). depth of some of these cracks were increased gradually and tended to incline towards the points of loading. finally, failure of specimen took place when the major diagonal crack suddenly opened over the entire of the slab depth within shear span at load (82.94 kn) as shown in plate 3. from figure 5, it can be noticed that the use of cfrp bars as a flexural reinforcement lead to decrease stiffness by increase the deflection at all stages of loading. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 315 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. plate 3. mode of failure and cracks pattern of specimen os.h26.hr100.hc0 figure 5. load deflection response of os.h26.hr100.hc0 specimen from figure 6 load deflection responses of specimen of this test group and when comparing these responses a clear difference in shape of their load–deflection responses is observed. it is obvious that the use of cfrp bars resulted in reducing stiffness of slab by increasing central deflection under the same moment. as expected theoretically, for same level loading, specimen (os.h26.hr50.hc0) yields a midspan deflection much lower than that for the specimen (os.h26.hr100.hc0) but larger than slab (os.h26.hr0.hc0). in fact, these differences in value of deflection at the mid span between specimens can attributed to the difference in the flexural stiffness (ec ie, where ec is the elastic modulus for concrete, kn/mm2, ie is effective moment area for the section of slab, mm4). for a cracked section, the stiffness is proportional to erard2 [59], where ar and er are elastic modulus and cross-sectional area for the reinforcement respectively, while, d is distance from extremely fiber in compression to the tension reinforcement centroid). therefore, the results of tests confirm activity of the steel reinforcement about improvement significantly both the ductility and stiffness of hybrid frpr.c. slabs with respect to those pure frpr.c. slabs. nevertheless, the final failure still brittle failure with slightly increasing in shear capacity of hcs section. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 316 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 6. load-deflection curves of (os.h26.hr0.hc0, os.h26.hr50.hc0 and os.h26.hr100.hc0) specimens 3.2. ductility ductility is usually well defined as the energy that absorbed by the materials up to the failure has been completed [16]. in the current study, ductility factors are evaluated according to the vertical disp. at ultimate load divided by vertical disp. at the service load [17]. as listed in table 6, it can be noticed that for specimens (os.h26.hr0.hc25,os.h26.hr0.hc50 and os.h26.hr0.hc75), ductility was increased by 25%, 31.25% and 60% respectively comparing with os.h26.hr0.hc0, this increasing in ductility is due to the increasing in ultimate load capacity resulted from the hybridization in strength of concrete that led to increasing ultimate deflection. 4. conclusions based on the experimental study carried out here for simply supported one way hollow core slabs, the following conclusions can be drawn within scope of this research: 1. using of cfrp bars as an internal reinforcement have slightly effect on the shear strength capacity of hollow core slab. on the other hand, cfrp reinforcement lead to decrease the stiffness of slab at post cracking stage; therefore, deflection will increase at the same load after cracking. 2. using of hybrid reinforcement (cfrp and steel bars) as internal reinforcement give better results of ductility compared with hcs reinforced with cfrp bars only. 3. using of hybrid reinforcement (cfrp and steel bars) as internal reinforcement have slightly effect on shear strength capacity (increasing it by about 4.5%). 5. references 1. hawkins n.m., ghosh s.k., 2006 "shear strength of hollow-core slabs", pci journal:110–114. 2. hollaway, l., "glass reinforced plastics in construction: engineering aspects", john wiley & sons; 1978. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 317 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. peece, m., manfredi, g. and cosenza, e., "experimental response and code models of gfrp rc beams in bending" j compos constr, asce 2000; 4(4):182–90. 4. rizkalla, s.h. and nanni, a., "field applications of frp reinforcement: case studies", american concrete institute (aci) special publication sp-215; 2003 5. codrut, f.s., tamas, n. g., valeriu, s., dan, d. "strengthening of hollow core precast slabs using frp composite materials – procedure, testing and rating" proceedings of the 11th wseas international conference on sustainability in science engineering, pp. 496-501 6. nanni, a., henneke. m.j and okamoto, t., "tensile properties of hybrid rods for concrete reinforcement", constr build mater 1994;8(1):27–34. 7. nanni, a., henneke, m.j and okamoto, t., "behavior of concrete beams with hybrid reinforcement", constr build mater 1994; 8(2):89–95. 8. bakis, c.e., nanni, a. and terosky, j.a., "smart, pseudo-ductile reinforcing rods for concrete: manufacture and test", in: saadatmanesh h, ehsani mr, editors. proceeding of first international conference on composite in infrastructure. tucson (arizona): university of arizona; 1996, p. 95–108. 9. lau, d. and pam, h., j., "experimental study of hybrid frp reinforced concrete beams", elsevier, engineering structures 32 (2010) 3857–3865 10. aci-318-11, acicommittee, "building code requirements for structural concrete",aci-318m14.and.commentary aci-318m-14, american concrete institute. 11. iraqi specification standards iqs no. 5, 1984 "portland cement", central agency for standardization and quality control, planning council, baghdad, iraq 12. iraqi specification standards iqs no.45, 1984 "aggregate from natural sources for concrete and construction", central agency for standardization and quality control, planning council, baghdad, iraq 13. astm c33-13 "standard specification for concrete aggregates", american society for testing and materials, 2013 14. hughes brothers, inc., 2010 "carbon fiber reinforced polymer (cfrp) rebar aslan 200/201", technical data sheet. 15. british standard institution (1997), "concrete. methods for specifying concrete mixes", bs 5328-2 16. hussain, m., alfarabi, s., basunbul a., baluch m.h., al-sulaimani g.j., "flexural behavior of precracked reinforced concrete beams strengthened externally by steel plates" aci structural journal, vol.92, issue.1, 1995. 17. jeffrey s. russell "prestrectives in civil engineering", commemorating the 150th anniversary of the american society of civil engineering, asce publications, 2003. p.375. تخفيض المقاومة الهيدروليكية بأضافة المواد البولميرية في الجريان الأضطراربي في الأنابيب ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٣ بإضافةفي األنابیب لجریان الماء االضطرابي مقاومة الھیدرولیكیةاللتقلیلتجریبیةدراسة البولیمیرات . – خالصة معامل يتغي ، ي . )(pam polyacrylamide،(% 0.025, 0.0130, علـى (0.005 )λ . ()pam ( )λ ((37.95% – 6.51) . )pam ((0.06% – على نسبة (0.005 )λ( لى )δλ / λ %(6.51%44.62 )λ(،)δλ / λ % ()cp*(0.030.042 : ( re = 25350 & 0.03%, re =28355& 0.033 % , re=34981&0.038 % , re=39360 & 0.039% , re=44985 &0.042%). : ، ، ، experimental study to reduce the hydraulic resistance of water turbulent flow in pipes by polymer additives abstract ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٤ the aim of this research is to study the effect of polymeric additives to water on friction coefficient change in a turbulent pipe flow which would cause in reduction of drag resistance. experiment is done using the polyacrylamide ( pam ) as polymeric additive to show the effect of addition of ( pam ) with case low concentrations (0.005,0.013 , 0.025%) on the friction factor (λ) . the results show that the addition of (pam) will reduce (λ) with a range from 6.51 to 37.95% comparable with the friction coefficient (λ) for water before addition in a turbulent flow case. also a study of the addition effect of ( pam ) with different concentrations between ( 0.005 – 0.06% ) on the reduction percent of (λ) is carried out . the results show increasing the effect of the addition (pam ) cause in increasing the reduction percent δλ / λ % with a range of 6.51 to 44.62% . it is found that the peak values called the optimum values(cp*)of pam between 0.03&0.042. increasing the addition of pam cause in decreasing the effect of reduction percent with concentrations at several reynolds number as follows: ( re = 25350 & 0.03%, re = 28355& 0.033 % , re=34981&0.038 % , re=39360 & 0.039% , re=44985 &0.042%). key words: polyacrylamide polymer (pam), friction factor (λ), reynolds number , reduction percentage δλ / λ %. pampolyacrylamide polymer λ friction factor λ1 λ2 معامل. δλ / λ % reduction percentage% re reynolds number k n vm / sec µ)( /kgكثا m3 νm3 δ hmpa lm dm qm3 / sec cppolymer concentration ldalaser doppler anemometry wppm ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٥ ة . ,toms)فة ا 1949) في . )lumley, 1969(، )hulsen & kulken , 1997( )lumley,1969 ;povkh, 1979 ; rabin, 1989( p a m . )wei and willmarth,1992((pam) )هي 0.005%) . . )du and frisch , 1996( . ٍsreenivasan and white, 2000)((pam) ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٦ ، . )tobiason, et al, 2001((pam) . )chernyuk, et al , 2002( 15% . . ,gyr and bewersdorff كما (2009)lda experimentslaser doppler anemometry 435)ي wppm))the strong shear-thinning behavior of the fluid(. )pam(olyacrylamidep: c3h5no . . tareke, et al., 2002)( )hydrolysis ()acrylontrile ( )nitrilehydratase( ،نیونكما بین ذلك جماعة من العلماء الصی.(gao, et al, 1999). )1 ()1([du, and frisch, لل[1996 : workexperimental ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٧ )2(. :تيت ١.flow meterي. ٢.test section . ٣.pr.gage. ٤.mixing tank. ٥.pump. ٦.constant reservoir . 225 ,draad :.مضافه (1996) (1)----[ 8v/d ]n-1=kµ knvd .µ) ( : re = ----(2) (%0.025, 0.013, 0.005) )1( )chernyuk ,2002(:l v2 ---. -----λδ h= d 2g ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٨ )λ ( )λ(مبينة في)2(. )wei and willmarth فـي . )1992 700 )2( . cp 1=polymer concentration cp% معامـل λ)%/(δλ0.005%0.06% )3(. %cp-)( . λ1 – λ2) / λ1%( =%λ/δ λ معامل نسبة هي. λ12(تمثل معامل( λ2عتمثل معامل. discussion&results :١.)3( , λ =f(re) يقل 0.025% , 0.013% , 0.005% translationة vorticityهية يdeformation ، ، )graebel, 2001( . ٢.)λ ( )2. ( 1498969978 ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٩ )lumley, 1969( . %cpنسبة .٣ %λ/λδيي.)8-3(في هكما λ/λδ ) *cp(يةلا -:*cpثالية re = 25350re = 28355cp* = 0.03% re = 34981cp*= 0.033% re = 39360cp*= 0.038 % re = 44985cp*= 0.042 % *cpم.٤ م م (warholic et al,1999)ث cp* >cpثلى.٥ م نسج λ/λδ ,denاكما )λ(م 1995)( onclusionsc 1 .0.005%0.025% re = 40000)3 ( 10.43 , 23.04 , 34.01 % . 2 .2535044985 %λ/λδ ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٠ 21.3244.620.03%% 0.042. 3. )4-8 (2535044985 . تتبع. 4 :: ( quadratic regression routine on calculator) مالئمة . المصادر chernyuk,v.v, pitsishin,b.s,orel,v.l, (2002). " influence of pam additives on the head loss in abrupt contraction and expansions of pipes" , j.of engineering physics and thermo physics.vol.75,no.4,pp910-919. den toonder, j.m.j., drag reduction by polymer additives in a turbulent pipe flow: laboratory and numerical experiments. ph.d. thesis, delft university of technology, delft, netherlands (1995). du,y.y,and frisch,h.l , (1996). " in physical properties of polymers" ,hand book, edited by j.e.mark . aip press,woodbury ,n.y.,pp241-248. draad, a.a., (1996)laminar-turbulent transition in pipe flow for newtonian and nonnewtonian fluids. ph.d. thesis, delft university of technology, delft, the netherlands. graebel w. r,(2001),"engineering fluid mechanics" , hand book,taylor &francis publishers, n.y, pp369. gao jp, lin t, wang w, yu jg, yuan sj, wang sm. (1999). "accelerated chemical degradation of polyacrylamide". macromolecular symposia 144: 179-185. issn 1022-1360 gyr, a. and bewersdorff, h.-w. (2009), drag reduction of turbulent flows by additives. kluwer academic publishers, dordrecht. hulsen,m.a ,kulken,g.d . (1997)" drag reduction by polymer additives in a turbulent pipe flow" ,j.fluid mech. vol.337,pp193-231. 34000 <re <25000δλ / λ =3.51x10-4 re1.5 cp – re cp 44900 < re <34000re0.73cp – 0.9re cp2 =δλ / λ 50000 < re <44900δλ / λ = 0.94 re (0.05cp – 0.6 cp2) ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦١ lumleyj.l ( 1969) .drag reduction by additives.ann.rev.fluid mech. vol.1 pp 367-374. povkh,e.l , (1976) . "technical hydromechanics" ,leningrad .pp 343-346. rabin,y,zielinska,b.j, (1989). "scale dependent enhancement and damping of vorticity disturbances by polymers in elongational flow" .phys. rev.lett. vol.63,pp 512-518. sreenivasan,k.r.,white,c.m , (2000). "the onset of drag reduction by dilute polymer additives and maximum drag reduction asymptote" .j.fluid mech. 409, pp 149-164. tareke e, rydberg p. kornbrust, b. a.; stringer, m. a., hendriksen, h. v. (2002). "analysis of acrylamide, a carcinogen formed in heated foodstuffs". j. agric. food. chem. 50 (17): 4998–5006. tobiason,e.k, jenkins,e,molash,e and rush,s , ( 2001) . " polymer use and testing for erosion and sediment control of construction sites" .erosion control.pp90101,january/february . toms, b.a., some observations on the flow of linear polymer solutions through straight tube at large reynolds numbers. in: proceedings 1st international congress on rheology. north holland, amsterdam (1949) pp. 135–141. warholic, m.d., schmidt, g.m. and hanratty, t.j., the influence of a drag-reducing surfactant on a turbulent velocity field. j. fluid mech. 388 (1999) 1–20. warholic, m.d., massah, h. and hanratty, t.j., influence of drag-reducing polymers on a turbulence: effects of reynolds number, concentration and mixing. exp. fluids 27 (1999) 461–472. wei,t and willmarth, w.w, (1992). " modifing turbulent structure with drag-reducing polymer additives in turbulent channel flow" ,j fluid mech. vol 245, pp619-641 . )1 ()(pampolyacrylamide c3h5nomolecular formula 71.08 g mol−1molar mass 1.13 g/cm3density 84.5 °cmelting point (polymerization)boiling point 2.04 kg/l (25 °c)solubility inwater )2 ( cp1=0.025%cp1=0.013%cp1=0.005%water λλλλre v m / sec q m3 / sec 0.02820.02760.02620.0284149890.9143.015x10-4 0.02810.02730.02590.0281161230.9833.24x10-4 0.02490.02710.02570.0270180461.13.62 x10-4 0.02410.02610.02570.0269196801.2013.96 x10-4 0.01880.02350.02550.0254245921.494.94 x10-4 0.01980.02130.02350.0251253501.514.97 x10-4 0.01790.02010.02200.0238283551.7295.71 x10-4 0.01580.01880.02130.0235349812.1337.03 x10-4 0.01520.01770.02060.0230393602.4127.91 x10-4 ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٢ )3( re=44985re=39360re=34981re=28355re=25350 δλ / λ %δλ / λ %δλ / λ %δλ / λ %δλ / λ % cp% 10.029.7410.27.746.510.005 14.5214.3314.4311.259.450.008 18.7218.1117.2414.0811.840.01 24.123.1221.7316.7514.310.013 27.5226.3525.7519.8216.670.016 32.3830.1429.0222.9218.940.02 37.9534.1232.6524.6321.10.025 40.9836.3334.0625.3421.320.03 42.5738.3234.3525.3521.360.033 42.9639.3833.924.6220.710.035 44.2139.6333.5523.2119.790.038 44.6239.2831.2421.2717.550.042 44.3937.8229.8018.4015.980.045 42.5236.2424.7814.1211.650.05 40.3431.6919.077.266.500.055 36.0526.9511.32000.06 )1 ()(pampolyacrylamide 0.01300.01600.01890.0209449852.7439.05 x10-4 0.01000.01460.01830.021549283.029.96 x10-4 0.00980.01290.01680.0208576303.51411.6 x10-4 0.00810.01270.01640.02046162883.72312.3 x10-4 0.00760.01250.01540.0202642883.92112.9 x10-4 0.00690.01150.01520.0198699784.29714.07 x10-4 ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٣ )2 ( 0.00 0.02 0.04 0.06 0.00 5.00 10.00 15.00 20.00 25.00 test section pr. gage flow meter mixing tank flow check point constant reservoir pr. line thermometer manometer pump manometer δλ / λ % cp % cp* % ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٤ اك عند جریان المحالیل البولیمیریھ والماءالعالقھ بین عدد رینولدز ومعامل األحتك) 3(شكل رقم reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 4(شكل رقم = 25350 0.00 20000.00 40000.00 60000.00 80000.00 0.00 0.01 0.02 0.03 0.04 w a te r ,c =0 % c =0 .0 0 5 % c =0 .0 1 3 % c =0 .0 2 5 % λ re ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٥ cp % =العالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 5(رقم شكل 28355re 0.00 0.02 0.04 0.06 0.00 10.00 20.00 30.00 cp* % δλ / λ % ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٦ cp % reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 6(شكل رقم = 34981 0.00 0.02 0.04 0.06 0.08 0.00 10.00 20.00 30.00 40.00 cp % reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 7(شكل رقم = 39360 0.00 0.02 0.04 0.06 0.08 0.00 10.00 20.00 30.00 40.00 δλ / λ % δλ / λ % cp* % ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٧ 0.00 0.02 0.04 0.06 0.08 0.00 10.00 20.00 30.00 40.00 50.00 cp % reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 8(شكل رقم = 44985 δλ / λ % cp* % al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 516 experimental study of r.c. corner details dr. jasim mahmud al-khafaji, asst. prof. in civil eng. dept., al-mustansiria university dr. zubaidah a. al-bayati, lecturer in civil eng. dept., al-mustansiriya university eng. ali a. khamis al-mallki, m.sc. in structural engineering abstract this investigation presents an experimental study of strength and behaviour of various types of reinforcement details in concrete corner subjected to bending moment tended to open the angle. ten specimens with various arrangements of reinforcement in the corner region are tested to study the effect of reinforcement detail, corner strength, cracks type, cracking moment, cracks pattern, corner deflection and corner efficiency. the specimens are designed to represent an actual prototype of a portal frame corner. the compressive strength of concrete in the test varies from (37.1) to (43.6) mpa, and steel tension ratio in legs is constant at ρ = 0.0081 in all test specimens. the nominal dimensions of the tested corners are (1077.8 mm) in overall length, (600 mm) in height and (150mm) in thickness, the nominal width, and the effective depth for all corner's leg section is held constant at (150 mm) and (129 mm) respectively. all corners are supported to be hinged in one leg by two hooks and rolled in other leg, also all corners are loaded by steel frame where, it produces moment tends to open the angle. concrete strains at three different loading stages are recorded for each tested corner; also load deflection curves were plotted. throughout the test operation crack patterns were drawn and the mode of failure of the tested corners is identified, which is divided into two types (flexural and bearing) failure. it was found that reinforcement detailing in corners subjected to moment tends to open the corner has important effect on the strength and the mode of failure of the corner. depending on the results of the current experimental work some details are recommended to be used in the field work. keywords: concrete, corner, reinforcement, detail, experimental study دراسة عملية لتفاصيل الوصالت الخرسانية المسلحة الجامعة المستنصرية/قسم الهندسة المدنية/جاسم محمود الخفاجي. د.م.أ الجامعة المستنصرية/قسم الهندسة المدنية/زبيدة عبد اللطيف البياتي. د دسة إنشائيةماجستير هن/المهندس علي عبد المحسن المالكي :الخالصــــة يستعرض البحث الحالي دراسة عملية لمقاومة وتصرف أنواع متعددة من تفاصيل التسليح لألركان الخرسانية المعرضة نماذج لتفاصيل تسليح مختلفة في منطقة األركان لدراسة تـأثير تفاصـيل ) 10(تم فحص . لعزوم إنحناء تعمل على فتح الزاوية صممت النماذج . الخرسانة، نوع التشققات، عزوم التشققات، أشكال التشققات، هطول الركن الخرساني وكفاءته التسليح، مقاومة al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 517 ) 43,6 و 37,1(مقاومة إنضغاط الخرسـانة فـي الفحوصـات تراوحـت بـين . لكي تمثل وتحاكي أركان الهياكل اإلنشائية = ρ(اويميكاباسكال، نسبة حديد الشد في سيقان األركان كانت ثابتة وتس أبعاد األركان التي . لكل النماذج المفحوصة) 0.0081 تم الحفاظ على العرض والعمق الفعال ثابتاً لـسيقان ). ملم للسمك150ملم لإلرتفاع و 600ملم للطول، 1077,8(تم فحصها هي أحد السيقان بإستخدام أسندت جميع األركان على شكل مفصلي في . على التوالي ) ملم129ملم و 150(كل األركان وبما يساوي تم تحميل جميع األركان بواسطة هيكل فوالذي يقوم بتوليد عزم يعمل على فتح . عقفتين وأسندت الجهة األخرى بمفصل متحرك تم تسجيل اإلنفعاالت في الخرسانة لثالثة مراحل تحميل مختلفة ولكل ركن تم فحصه كما وتم رسم منحيـات الحمـل . الزاوية عملية الفحص تم رسم التشققات الحاصلة في الركن الخرساني وتحديد نوعية الفشل الحاصلة والتي كانت علـى أثناء. واإلزاحة لقد تبين بأن تفاصيل التسليح في األركان الخرسانية المعرضة لعزوم انحناء تعمل علـى فـتح ). فشل إنحناء أو إرتكاز (نوعين باإلعتماد على النتائج المستحصلة مـن البحـث . لحاصل في الركن الخرساني ا الزاوية لها تأثير كبير على مقاومة ونوع الفشل .الحالي تم إختيار عدد من التفاصيل والتوصية بإعتمادها في المجال الحقلي nomenclature bf width of compression face of member, (mm) d distance from extreme compression fiber to centroid of longitudinal tension reinforcement, (mm) ' cf cylinder compressive strength of concrete, (mpa) fy specified yield strength of reinforcement, (mpa) mcr first cracking moment, (kn.m) (mcr)r first cracking moment of reference corner, (kn.m) mu factored moment at section, (kn.m) (mu)r ultimate moment of reference corner, (kn.m) ∆c total deflection for corners specimens ∆r total deflection for reference corner steel reinforcement ratio introduction in numerous structures, continuity between two adjacent members is necessary even though the members angle. the joint formed from this meeting usually refers to the "corner". the term ''corner'' in this investigation is used to describe a corner joint formed by the joining; at 90o, of the ends of two flexural members (mayfield et. al, 1971). the terms ''opening'' and ''closing'' the corner are used to describe the increase and decrease of this right angle (mayfield et. al, 1973), respectively. concrete corners are found in wide variety of structures such as retaining walls, bridges and portal frame buildings. they are also common in the field of hydraulic structures, such as reservoirs, tanks, flumes and culverts. various detailing systems have been in vogue from time to time and considerable efforts have been directed towards carrying out improvements in these detailing systems to achieve the desired structural behavior. in general, the failure of opening corners is invariably characterized by the low tensile strength of concrete resulting in the initiation of a splitting tensile crack originating at the reentrant corner and gradually moves out along the corner diagonal towards the exterior corner (nilsson, 1973) and (nilsson and losberg, 1976). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 518 dimensions of tested corners the nominal dimensions of the tested corners is as shown in figure (1 a). the cross section details are shown in figures (1 b) and (1 c). the inner and outer angle of corner is right angle (90o). the corner pad is (70mm) in height and (70mm) in width. reinforcement details the types of reinforcement details used in this work are, as shown in figure (2) where,(c means corner and the number represents the type of detail). detail (c1) involves only simple 90o bends in the main steel in corner region, detail (c2) involves vertical stirrup in corner region, detail (c3) involves two vertical stirrups in corner region, detail (c4) involves three vertical stirrups in corner region, detail (c5) involves horizontal stirrup in corner region, detail (c6) involves vertical and horizontal stirrup in corner region, detail (c7) involves two vertical and one horizontal stirrups in corner region, detail (c8) involves a 270o bend in the tension steel (loop bar) in corner region, detail (c9) involves a 270o bend in the tension steel (loop bar) with 45o bend in compression steel in the corner region, detail (c10) involves a 270o bend in the tension steel (loop bar) with 45o bend in compression steel with vertical stirrup in corner region. testing of corners all corner specimens are tested by using the universal testing machine (mfl system) under monotonic loads up to failure. according to the circumstances of this test, the specimen (concrete corner) is supported to be hinged at one leg and rolled in the other leg upon this apparatus, using two hooks in one side to achieve the hinged situation. the upper and lower parts of concrete corner are modified to make the applied loads act as a coupled situation on each side, this leads to open the corner at center, as shown in figures (3) and (4). the distance between the two point loads is kept constant at (93 mm). the applied loads are concentrated by adjustment of steel frame that has two legs settled on the specimen's pad under hydraulic jack, as shown in figure (3). thin wooden patches are inserted between the concrete and points of loads to provide even surface. the loads are applied in successive increments up to failure. at the end of each load increment, observations and measurements are recorded for the corner deflection, at the reinforcement angle strain gauge readings and crack development and propagation on the corners surfaces. types of cracks in the current investigation two type of cracking are found, the first one is" flexural cracks" usually (in most specimens), these are the first to appear, starting in the middle of the legs and move to the corner base. in some corners, additional flexural cracks appear at high loads, in positions nearer to the corner region than the initial cracks appear at first. generally, the first flexural cracks appear at small percentage of the measured ultimate loading, see figure (5), and continue to widen and extend until they reach the compression reinforcement when they either cease to extend or continue at a very much reduced rate but nevertheless continue to widen or extend after that. the second type is "diagonals cracks" these are the cracks which appear at the corner region, either at or parallel to the diagonal of corner crack, see figure (5). at least one diagonal crack appears in each corner. generally, this crack starts approximately in half distance between the inner and outer angles of the specimen, and continues to widen and extends at both ends until it reaches the vicinity of the main reinforcement. it then ceases to extend, but continues to widen until failure. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 519 cracking moments flexural cracks and diagonal cracks both are noticed to appear at the different stages of loading. since the flexural cracks are the first to appear; therefore, the word 'cracking moment' whenever it appears in this investigation will refer to the flexural cracking moment. cracking moment is that moment at which the first visible surface crack is seen by the naked eye on the surfaces of the corner. values of cracking moment are shown in table (1). the cracking moment is not high variable with different details. table (1) shows that the first visible crack moment of the corners vary from (33.3%) to (62%) of the experimental ultimate loads. for all tested corners, comparison will be performed with first cracking moment for reference corners (mcr) r. for corners cast with diagonals (vertical) stirrups in corner region (c2, c3 and c4), these diagonals stirrups increase the cracking moment where they produce the first crack about (19%, 61% and 47%) respectively compared with the ultimate load of reference corner (c1). this is due to the ability of the diagonals stirrups in arresting crack growth and crack widening in corner region (strabo et. al., 1982) and (shiohara, 2004). the effect of diagonal stirrups in increasing the cracking moment for corner (c3) is greater compared with (c2 and c4), due to the two vertical stirrups placed in corner region where that produces more bond force arresting crack growth and equals the force (push out force) that try to split the rectangular block of corner (suparviriyakit and pimanmas, 2007) . for corners cast with diagonal (horizontal and vertical) stirrups in corner region (c5, c6 and c7), the maximum increase is (5%, 12% and 26%) for (c5, c6 and c7) respectively. these few advantages may be due to the low resistance of the horizontal stirrup for the spilt force in corner region and little bond force along the diagonal direction. for corners with looped tension bar in corner region (c8, c9 and c10), high increase in first cracking moment occurs which, is due to the looped bar where it has a tension component across the diagonal crack and helps to provide force (push out force) equal to splitting force in corner region (uma and prasad, 2008) and (lee et. al., 1977) and also that loop of the detail encloses a large part of the concrete in the corner (balint and taylor 1972). the maximum increase in first cracking moment is (54%, 33% and 33%) for (c8, c9 and c10) respectively. as expected, corner specimens made with vertical stirrup exhibit large cracking moment compared with the other types of details. this enhancement is mainly due to the bond force in vertical stirrup arresting mechanism of crack propagation. cracks pattern figure (6) shows the crack patterns at failure for all corners tested under bending moment tending to open the angle. they also show the load that crack observed in it and the extent of the crack at that load. the patterns of the flexural cracks in the legs of the corner are similar for all the corners, as shown in figure (6). the first cracks to appear are the two cracks which are very close to the critical sections, one in each leg. these cracks extend and widen until they reach the compression zone of the section where they either terminate or change directions. while the loading processes continue, more flexural cracks appear and extend, in the same way along both legs. diagonal crack patterns, unlike those of the flexural cracks, are different from corner to corner according to the type of detail. as shown in figure (6), in corners with details (c7, c8, c9and c10), then diagonal cracks are positioned close to the critical sections and nearly parallel to the flexural cracks, and in high percentage of load cracks appear near the outer angle of corner. that is because the looped tension bar in corner block arrests cracks in all directions. for corners with details (c2, c3, c4), the diagonal cracks appear in the middle distance between the inner and outer corner and perpendicular to vertical line between them, that is because the tension force that tries to split the rectangular block more than the bond force is created by vertical stirrups. for corners with al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 520 details (c5 and c6), the diagonal crack starts from the inner angle of corner and extends to the legs, also in high percentage of load cracks appear near the outer angle of corner. the reference corner (c1) has random diagonal crack pattern where the cracks appear near the inner and outer angle and extend to perpendicular or parallel the leg section, because no stirrup exists in corner region due to poor bond force. the number of the diagonal cracks also differs as the detail is changed. diagonal cracks usually appeared at loads higher than those of the flexural cracks. concrete strain measurements of concrete strain are taken on both legs and on the corner region. the collected data at 10, 30 and 50 kn are drawn in figure (7). readings of this strain at different loading stages are plotted, against the depth of diagonal section. in these figures, each case consists of three curves with different slopes. each curve represents certain stage of loading. figure (7) represent the strain along the diagonal where, in all ten specimens the strain has maximum value at the inner corner and it is tensile in nature as a result for that, the inner corner is subjected to high biaxial state of tensile stresses resulting in cracking at the inner corner along the diagonal. this necessitates reinforcement across the crack at the inner corner. any reinforcement detailing without this steel will be deficient in controlling the inner corner cracking. in some portions of the corner, tensile stress value is higher than the tensile strength of concrete, this may cause cracking and pushing out of the concrete. deflection during the tests, the deflection readings are recorded at the inner angle of the corner, immediately after the application of the load. the load ─ deflection curves for the corners tested under bending moment tend to open the angle up to failure are shown in figure (8). in this figure, the curves in general consist of three parts each; however the curves for corners with detail (c1, c2, c4, c5, c6, and c7) consist of three parts, as shown. the first part, starts form zero load up to the formation of the first flexural cracks, is of relatively steeper slope which in turn means that the corners at this stage are of relatively higher flexural rigidity. the second part of the load-deflection curve extends from the point of the first yielding to the point at which yielding of all reinforcement takes place at any of the two critical sections or both. the third and final part of the load-deflection curve extends from the point of yielding at the critical section to failure of corner. this part is relatively linear and the corners at this stage have little rigidity in flexure. the load deflection curve for the corners with details (c8, c9 and c10) consists of one or two parts generally, where the loaddeflection curve of corner with detail (c9) has one part starting from zero to failure point, this part is very steeper slope. that means the corner with that detail has higher flexural rigidity. for corners with details (c8, c9 and c10), the load ─ deflection curves consist of two parts, the first part starts from zero load point to first crack load point, that part is very steeper and very short. the second part is liner to the failure. from all the curves of load ─ deflection, it appears that for corners with different details, the slopes of all parts of the curves become steeper when the looped bars are used in corner region (c8, c9 and c10). the variation in the slope of the first part is very small as compared with those of the other parts. so this indicates that the effect of the formation of the concrete cracks on the rigidity of the corner decreases with the usage of the diagonal stirrups and looped bars in corner region. the total deflection for tested corners is shown in table (2); this table shows the decrease in total deflection for most corners when compared with reference corner deflection. for corners cast with vertical stirrups in corner region (c2, c3 and c4), the maximum decrease in total deflection is (24%, 80% and 30%) respectively, compared with the total deflection of reference corner. this is due to the ability of vertical stirrups in increasing the strength of corner, increasing the stiffness and decreasing the rotation in corner, as a result, the total deflection is decreases. for corners cast with horizontal stirrups (c6 and c7), the decrease is in total deflection (63% and 25%). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 521 corner (c5) has an increase in total deflection which is (33%), where this is not expected because the horizontal stirrups increase the strength of corner and also decrease the rotation in corner. this increase in total deflection is mainly caused by the lack of reinforcement in the region of the corner (nilson et. al., 2004). for corners cast with looped bar (c8, c9 and c10), the decrease in total deflection is (76%, 85% and 49%) respectively, compared with the total deflection of reference corner, that is also because the increase in corner strength where the looped of detail encloses a large part of the concrete in the corner, as the corner is opened the loop tightens and restrains the concrete inside it. mode of failure the mode of failure of the corners tested in this investigation, under bending moment tented to open the angle, could be divided in general into two types. the first one takes place in the legs of the corner mainly after crushing of the concrete at the inner angle, and extending of the flexural cracks near the critical sections, beyond tension reinforcement or in the middle of legs. this type of failure will be called, in this discussion as ''flexural failure''. generally, this type of failure is found to occur at corners with details (c2, c3, c4, c8, c9 and c10). these corners fail with flexural failure because of the ability of looped bars and vertical stirrup to resist and arrest the cracks in corner region and increase the strength of corner region where this leads to the corner region stronger than legs, as result for that, the failure appears in the legs at first. the second type of failure occurs at the corner region in which complete destruction of the concrete in the corner region occurs. this type of failure is thought to be due to failure in the bearing of the concrete within the bends of the tension and compression bar, and; therefore, it will be called ''bearing failure''. this type of failure generally takes place at corners with details (c1, c5, c6 and c7). table (3) shows the mode of failure for all corners. ultimate strength of corners when the applied load to corner tends to open the angle, the detailing of reinforcement has an important effect on strength of corner. table (4) shows the ultimate strength of tested corners and also shows that detail (c1) is not usually considered adequate detail; it is inferior to many other details except detail (c5), but detail (c1) shows that stirrups near the corner are effective in increasing strength. detail (c2) through (c7) attempts to improve the performance of detail (c1) by the use of diagonal stirrups (vertical and horizontal). the test results show that diagonal stirrups as positioned in detail (c2, c3 and c4) increase the strength where the increase in strength is (30%, 23% and 20%) respectively, compared with ultimate strength of reference corner (c1). when turned through 90o (as in detail c5 and c6) it gives strength less than strength of reference corner. this increase in strength is mainly due to the presence of vertical stirrup and also the increase in the area of diagonal steel (uma and prasad, 2008) where, to ensure a good mechanical interaction between the main reinforcement and the stirrup it is necessary to violate the requirement of a minimum of (1.875 cm) concrete cover over the reinforcement. according to new styles of diagonal stirrups, as in details (c7) they give less advantages in strength about (3%), and less than details (c2, c3, and c4). in particular, results for details (c2, c3 and c4) are very satisfactory, detail (c2) is preferable to details (c3 and c4) because there is (one, two) stirrup which has less than detail (c3, c4) respectively and hence it would be cheaper and easier than details (c3, c4). the details (c8, c9 and c10) that have more high strength than detail (c1) (used in reference corner) about (60%, 90% and 83%) respectively, where that because the lapped tension steel tends to corner region and that leads to more bond force between the concrete and reinforcement and more steel area in corner region. these specimens (c8, c9, and c10) are expected to be the strongest corner due to the distribution of steel in the corner region; it is thought that the bond strength between the deformed bars and the concrete would be strong enough to prevent major slippage at an early stage. the thickness of the al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 522 concrete cover measured from the plane of the loop has some influence on the strength of such corner. obviously with a greater thickness, the splitting tendency of the loop would be somewhat restrained. the strength of a corner reinforced with the loop is also found to be dependent on the radius of the loop, a larger loop giving a stronger corner. corners efficiency the efficiency of a corner is defined as a ratio of the strength of the corner from a test to the theoretical strength of the corner (mayfield et. al., 1972). the results of corner opening by the moment show that the efficiency of corners (c8, c9 and c10) has been the higher than the others (see figure (9) and table (5)) (about 132%, 157.5% and 152%) because the main tension steel is protracted to most parts of corner region. that leads to more bond force between the concrete of corner region and the reinforcement; also the circular part of main steel resists the cracks in all directions. as a result, the strength is increased that leads to increase the efficiency. from the same figure it is shown that the efficiency of corners (c5, c6 and c7) is low (about 75%, 77.2% and 85.3%). this emphasizes of the weakness of these corners because of the little bond in corner block between the horizontal stirrup and concrete of corner block. also, the main steel is not protracted to all corner regions. the corners (c2, c3 and c4) have a good efficiency compared with reference corner (c1) that is because the vertical stirrup produces good bond between the reinforcement and the concrete of corner region. moreover, the vertical stirrups resist the diagonal cracks. the reference corner (c1) has lower efficiency and would be unsafe in design. the reason why that corner is weak is that; there is no steel across the diagonal direction to carry the tensile forces. from the results of test, it is found that the efficiency of all corners is good, see figure (9) and it is obtained that the reinforcement detail is an important parameter for corner efficiency. conclusions the following conclusions are drawn only from the ten types of corner details studied in this investigation: 1. when the applied load is opening the corner, reinforcement detailing has important effects on strength, and its effects on cracking moment, cracking pattern, cracks type are obvious. 2. details (c1, c5, c6 and c7) should be avoided, because they have efficiency less than (100%) and their joints fail before their legs (bearing failure). 3. details (c8, c9 and c10) have high efficiency (more than 100%) and they are the strongest details but not favorite because they are difficult and high in cost. 4. details (c2, c3 and c4) have acceptable efficiency (more than 100%), but detail (c2) seems to be the best choice because it would be cheaper and easier than details (c3 and c4), and also the diagonal stirrup in it does not need be placed with great accuracy and easy for compaction of the concrete in the congested corner zone. 5. the diagonal stirrups positioned in vertical direction (as in details c2, c3 and c4) definitely increase the strength and it is not necessary to bend or fix these stirrups to give a close tolerance, but that when turned through 90o (as in details c5, c6 and c7) they give less advantage, detail (c7) is an exception to this, possibly because the two vertical stirrups in it. 6. the nature of load deflection curves for all specimens is similar where it consists of three parts except the specimens (c8, c9 and c10) which consists of two parts. 7. ultimate moment carrying capacities, as observed in the test, are different with different details, where the detail (c9) has the highest magnitude (16.34 kn.m) and detail (c5) has the lowest magnitude (7.81 kn.m). 8. from the test results, reinforcement detailing for concrete corner subjected to bending moment opening the angle is suggested with: (a) inclined steel or loop steel across the diagonal of the corner as in details (c2, and c9). (b) stirrups near the inner angle of corner, as in detail (c1). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 523 reference 1. balint p.s. and taylor h.p.j. "reinforcement detailing of frame corner joints with particular reference to opening corners" cement and concrete association, technical report, tra 434, london, february 1972, 14 pp. 2. lee d.l., wight j. k., and hanson r.d., and members of asce "reinforced concrete beamcolumn joints under large load reversals" proc. asce, vol.103, (st12), 1977, pp.2337-2349. 3. mayfield b., kong f. k., bennison a. and davies j. c. d. t., "corner joint details in structural lightweight concrete" aci journal, may 1971, vol.68, no.37, pp. 366-371. 4. mayfield b., kong f. k. and bennison a. "strength and stiffness of lightweight concrete corners" aci journal, july 1972, vol.69, no.38, pp. 420-427. 5. nilsson i.h.e. "reinforced concrete corners and joints subjected to bending moment–design of corners and joints in frame structures" document d7:1973, national swedish institute for building research, stockholm, 1973. 6. nilsson i.h.e. and losberg a. "reinforced concrete corners and joints subjected to bending moment" proceeding asce, vol.102, no.6, 1976, pp.1229-1253. 7. nilson a.h., drawin d. and dolan ch. w. " design of concrete structures" thirteenth edition, the macgraw-hill edition, 2004, 733p. 8. shiohara h. "quadruple flexural resistance in r/c beam –column joints" 13th world conference on earthquake engineering, vancouver, b.c, canada, august 1-6, 2004, paper no. 491. 9. strabo j., andersen n.h. and nielsen t.b. "concrete frame corners" aci journal, july 1982, vol.81, no.4, pp.310-317. 10. suparviriyakit t. and pimanmas a. "compa rative performance of a substandard beam-column joint with and without initial bond between beam bars and concrete in the joint core" thammasat int. j. sc. tech., vol.12, no.1, january-march 2007, pp42-51. 11. uma s.r. and prasad a.m. "seismic behavior of beam column joints in reinforced concrete moment resisting frames" research project produced to indian institute of technology, madras chennai, 2008, 29 p. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 524 table (1) cracking moments for tested corners * reference corner ** (mcr) r is the first crack moment for reference corner = 4.08 kn.m table (2) total deflection for tested corners corner no. c1* c2 c3 c4 c5 c6 c7 c8 c9 c10 total deflection(mm) 12.15 9.23 2.32 8.54 16.2 4.55 9.15 2.95 1.87 6.25 ∆c/∆r 1 0.76 0.2 0.7 1.33 0.37 0.75 0.24 0.15 0.51 mu 8.60 11.18 10.61 10.32 7.81 8.03 8.89 13.76 16.34 15.77 * reference corner ∆c = total deflection for corners specimens ∆r = total deflection for reference corner table (3), mode of failure for tested corners table (4), ultimate strength for tested corners * reference corner mu = ultimate strength of tested corners (mu)r = strength of reference corner = 8.6 kn.m table (5), experimental work results corner no. c1* c2 c3 c4 c5 c6 c7 c8 c9 c10 mcr (kn.m) 4.08 4.87 6.59 6.02 4.30 4.58 5.16 6.30 5.44 5.44 mu (kn.m) 8.60 11.18 10.61 10.32 7.81 8.03 8.89 13.76 16.34 15.77 mcr/(mcr)r** 1 1.19 1.61 1.47 1.05 1.12 1.26 1.54 1.33 1.33 mcr/mu% 47.4 43.5 62 58 55 57 58 45.8 33.3 34.5 corner no. c1 c2 c3 c4 c5 c6 c7 c8 c9 c10 mode of failure bearing failure flexural failure flexural failure flexural failure bearing failure bearing failure bearing failure flexural failure flexural failure flexural failure corner no. c1* c2 c3 c4 c5 c6 c7 c8 c9 c10 ultimate strength(kn.m) 8.60 11.18 10.61 10.32 7.81 8.03 8.89 13.76 16.34 15.77 mu / (mu)r 1 1.3 1.23 1.2 0.91 0.93 1.03 1.6 1.9 1.83 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 525 * mcal =ρ fy (1-0.59ρ ' c y f f )bf d2 cracking moment kn.m corner no. detail type mcr crack positio n mu mcr/mu % m cal* m test efficiency % mode of failure cylinder strength mpa c1 4.08 right leg 8.60 47.4 10.50 8.37 76.5 bearing failure 43.6 c2 4.87 right leg 11.18 43.5 10.50 11.18 106.5 flexural failure 43.6 c3 6.59 corner region 10.61 62 9.72 10.61 102 flexural failure 37.5 c4 4.30 corner region 10.32 58 9.72 10.32 99.36 flexural failure 37.5 c5 4.30 corner region 7.81 55 9.82 7.81 75 bearing failure 38.1 c6 4.58 corner region 8.03 57 9.82 8.03 77.2 bearing failure 38.1 c7 5.16 corner region 8.89 58 10.25 8.89 85.3 bearing failure 39 c8 6.30 right leg 13.76 45.8 10.25 13.76 132 flexural failure 39 c9 5.44 right leg 16.34 33.3 10.54 16.34 157.5 flexural failure 37.1 c10 5.44 left leg 15.77 34.5 10.54 15.77 152 flexural failure 37.1 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 526 550 20 0 25 0 figure (1), details of tested corners: (a) overall dimensions (b) leg cross section (c) corner base cross section c1 c2 c3 c4 c5 c6 c7 c8 c9 c10 figure (2) reinforcement details al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 527 figure (3), corner set up figure (4), corner loading arrangement figure (5), cracks pattern, cracking load, cracks type al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 528 c2 c3 c4 c5 c6 c7 c8 c9 c10 figure (6), crack pattern at failure al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 529 c1 c2 c3 c4 c5 c6 c7 c8 c9 c10 figure (7), concrete strain curves for all corners al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 530 c2c1 c3 c4 c5 c6 figure (8), load-deflection curves for corners 1 to 6 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 531 figure (8), load-deflection curves for corners 7 to 10 figure (9), corners efficiency 1-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 synthesis and optimization of epicyclic-type automatic transmissions based on nomographs e. l. esmail k. h. salih lecturer assistant lecturer department of mechanical engineering machinery and equipment department college of engineering institute of technology university of qadisiya foundation of technical education dewaniya, iraq. baghdad, iraq abstract a new methodology is developed to design and optimize epicyclic-type automatic transmission gear trains using kinematic nomographs. from such nomographs, the kinematic characteristics of an epicyclic gear mechanism can be expressed in terms of the gear ratios of its gear pairs. the main properties of this methodology are that; from a single nomograph, the angular velocities for all of the coaxial links can be estimated and compared directly without specifying the exact size of each gear, the angular velocities can be arranged in a descending sequence without using complicated techniques, and all of the feasible clutching sequences can be enumerated directly. the optimization procedure to find the optimum gear ratios is applicable to any transmission mechanism composed of two or more fundamental gear entities (fges) depending on kinematic and geometric constraints. the reliability of the methodology is established by applying it to the conventionally available three-velocity simpson gear train for which optimal gear ratios are fully available. the theoretical results are in complete agreement with the practical applications. keywords: automatic transmission, epicyclic gear train, gear ratio, nomograph, and optimization . / // . یه . : . .سیه al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 صناعیا .ه 1. introduction most automatic transmission mechanisms employ epicyclic gear trains (egts) to achieve a set of desired velocity ratios. figure 1 shows an egt employing the simpson gear set as the ratio-change gear train. this gear train with the above clutching sequence is the most popular gear train. it has been developed by nearly all automotive manufacturers as three-velocity automatic transmissions [tasi 2001]. it can be found in ford c3, ford c5, mercedes benz, toyota a40 and nissan, to name a few. in an egt, the velocity ratio is defined as the ratio of the input shaft velocity to the output shaft velocity. various velocity ratios are obtained by using clutches to connect various links to the input power source and to the casing of a transmission gearbox, respectively. typically, a rotating clutch is used for connecting two rotating links and a band clutch is used to fix a link to the casing. in figure 1 rotating and band clutches are denoted by c and b, respectively. also it is always possible to achieve a direct drive by locking all the links in the egt together such that they rotate as a single link. the velocity ratios selected for a transmission are tailored for vehicle performance and fuel economy. typically, they include a first gear for starting, a second and/or third gear for passing, an overdrive for fuel economy at road speeds and a reverse. a table depicting a set of velocity ratios and their clutching conditions is called a clutching sequence. table 1 shows the clutching sequence of the transmission shown in figure 1, where an xi indicates that the corresponding clutch is activated on the ith link for that gear. for example, when the mechanism is in the first gear, the rotating clutch c1 and the band clutch b1 are activated. hence, link 4 is connected to the input power and link 1 is fixed to the casing. in arranging a clutching sequence, it is highly desirable to achieve a single-shift transition, i.e., only one clutch is turned on while another is simultaneously turned off between two successive velocity ratios. the gear ratios for the ford c4 transmission as an example of a three-velocity automatic transmission that uses a simpson gear train, are: 2.46:1 1st gear, 1.46:1 2nd gear, 1.00:1 3rd gear, and 2.20:1 reverse [11]. ford motor company has five basic transmissions that use the simpson gear train and are quite similar to each other: the c-3, c-4, c-5, c-6, and a4ld. the a4ld is a 4speed, whereas the others are 3-speeds. most general motors' transmission and transaxles are based on the simpson gear train. the turbo hydramatic (thm) 375, 400, and 475 transmissions are heavy-duty transmissions generally used in full-sized rare wheel drive (rwd) cars and trucks. the 425 is based on the same design as the others but had been modified for use in forward wheel drive (fwd) vehicles with a longitudinally placed engine. the 3l80 (thm 400) was introduced in 1964 and has been used by all divisions of general motors, as well as by many different manufacturers, such as jaguar and rolls-royce. the thm 250, 250c, 350, 350c, and 375b transmissions are 3-speed units. the 250 and 250c are light-duty, the 350 and 350c are medium-duty, and the 375b is a heavy-duty version of the 350 [12]. [mogalapalli 1993] developed an interactive design system for the design of automatic automotive transmission gear trains. mogalapalli's system can optimize the gear ratios using the augmented lagrangian multiplier method. in what follows an overview to the optimization theory is given [arora 2004]. 2. optimization theory overview optimization techniques are used to find a set of design parameters, },....,,{ 21 nxxxx , that can in some way be defined as optimal [mogalapalli 1993]. in a simple case this might be the minimization or maximization of some system characteristic that is dependent on x. in a more advanced formulation the objective function, f(x), to be minimized or maximized, might be subject al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 to constraints in the form of equality constraints, )....,,1(0)( ei mixg ; inequality constraints, )....,,1(0)( mmixg ei ; and/or parameter bounds, ul xx , . a general problem (gp) description is stated as )(min xf x , subject to )....,,1(0)( ei mixg )....,,1(0)( mmixg ei where x is the vector of length n design parameters, f(x) is the objective function, which returns a scalar value, and the vector function g(x) returns a vector of length m containing the values of the equality and inequality constraints evaluated at x. an efficient and accurate solution to this problem depends not only on the size of the problem in terms of the number of constraints and design variables but also on characteristics of the objective function and constraints. when both the objective function and the constraints are linear functions of the design variable, the problem is known as a linear programming (lp) problem. quadratic programming (qp) concerns the minimization or maximization of a quadratic objective function that is linearly constrained. for both the lp and qp problems, reliable solution procedures are readily available. more difficult to solve is the nonlinear programming (np) problem in which the objective function and constraints can be nonlinear functions of the design variables. a solution of the np problem generally requires an iterative procedure to establish a direction of search at each major iteration. this is usually achieved by the solution of an lp, a qp, or an unconstrained sub-problem. in transmission design, optimization based on desired velocity ratios and mechanism kinematic and geometric constraints generates the best possible gear ratios. optimization uses an objective function, based on a set of design variables and constraints, assigns a numerical value to the desired or required velocity ratios. the design variables stem from the physical constraints. along with the numerical algorithm, the objective function plays a big role in the effectiveness of the optimization problem [arora 2004]. 3. nomographs nomograph is defined as three or more axes, or scales, arranged such that problems of three or more variables can be solved using a straightedge. in the particular case of egts, a nomograph can be constructed using three or more vertical parallel axes [esmail 2007, 2008]. a basic egt consists of a sun gear, a ring gear, a planet, and a carrier as shown in fig. 2. figure 3 shows the basic form of the graph to be created for a basic egt. the term "gear ratio" is used in this paper to denote the ratio of a meshing gear pair. it is defined by a planet gear p with respect to a sun or ring gear x xpxp zzn , (1) where zp and zx denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative sign depends on whether x is a ring or sun gear. considering the kinematics of a fundamental circuit, the fundamental circuit equation can be written as [buchsbaum and freudenstein 1996]: xpcpcx n ,)()( (2) equation (2) can be re-written for the links of the basic egt as follows al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 rpcpcr n ,)()( (3) spcpcs n ,)()( (4) 1)()( , ppcpcp n (5) and 0)()( , cpcpcc n (6) these values have been used to place the axes of the nomograph shown in fig. 3. the c axis passes at the origin, and the p axis is one unit apart from it. let the symbol z yxr , denote the velocity ratio between links x and y with reference to link z, where x, y and z are any three links in the gear train. applying eq. (2) twice for links y and z and simplifying it yields: zpyp zpxp zy zxz yx nn nn r ,, ,, , (7) from the nomograph shown in fig. 3, we can find directly that rp sp cr csc rs n n r , , , (8) rn n r c rsrp spc sr ,, , , 1 (9) r n n n nn r c rs rp sp rp rpspr cs , , , , ,, , 11 (10) and 1)1(1 1 1 11 , , ,,, , r r rrr r c rs c rs c rs c sr s cr s rc (11) 3.1 clutching sequence nomograph due to the fact that an egt can be decomposed into several fgts [chatterjee and tsai, 1995, 1996] the kinematics of an egt is closely related to the kinematics of each individual fge. in order to derive a clutching sequence, it is important to unify the nomographs of the fges in one nomograph called the system nomograph and develop a methodology for arranging the output velocities in a sequence. we first unify fges that are connected to each other by two common links i.e. having two links with the same labeling, as shown in fig. 4. let b1 and b2 be the common links, p )1( be the first planet of the first fge or subsystem to be unified, y be any link from the second fge (not the basic one) other than b1 and b2, then by using link b1 as a bridge, we express the velocity ratio r b py 2 , )1( of link y with respect to the basic fge in terms of two of the velocity ratios of the fges or subsystems as al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 rrr b pb b by b py 2 )1(,1 2 1, 2 )1(, . (12) where r b pb 2 )1(,1 is associated with one of the fges or subsystems (basic one) and r b by 2 1, is associated with the other fge or subsystem. now, we shall deal with link y as if it were a link that belongs to the basic fge. from the unified nomograph, and making use of eq. (7), we can write 2,)1()1(,)1( 2,)1(,)1(2 )1(, n bppp bpypb py nn n r (13) where n pp )1(,)1( is equal to one and n ,)1( yp is the virtual gear ratio of link y in terms of the planet of the basic fge or the distance between the first fge carrier and link y axes on the unified nomograph . for a particular egt, two nomographs are drawn in fig. 5. since b2 is the carrier in this train, then making use of eq. (6), n bp 2,)1( is zero. applying eq. (13) yields n ,)1(2 )1(, yp b py r (14) combining equations (12) and (14) yields rr b pb b byyp 2 )1(,1 2 1,,)1( .n (15) for a system having more than two fges, the unification process continues between fges and/or unified subsystems until the highest-level system becomes the required mechanism. this way, a system nomograph can be obtained in terms of the gear ratios of its gear pairs. the simpson gear train which is composed of two single-planet fges will be used as a design example to illustrate the present methodology. figure 6 shows the unification process and the system nomograph for the simpson gear train. the gear ratios for this train are 22522,5 zzn (16) 23523,5 zzn (17) 464,6 zzn (18) and 13613,6 zzn (19) it can be shown that 10 22,5n (20) 023,5n (21) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 4,6n (22) and 013,6n (23) from eq. (12) rrr 2 6,32 3,12 6,1 . (24) from the first fge nomograph 13,6 2 6,3 nr (25) and from the second fge nomograph 22,523,5 22,52 3,1 nn n r (26) substituting eqs (25) and (26) into eq. (24), yields 22,523,5 13,622,52 6,1 . nn nn r (27) but from the unified nomograph 1,6 2 6,1 nr (28) therefore 22,523,5 13,622,5 1,6 . n nn nn (29) figure 7 shows the basic form of the unified system nomograph for the simpson gear train without the planet axis. here it is called the basic form of clutching sequence nomograph. as shown in fig.7, the ranges of output velocities can be classified into three kinds: drive (d), overdrive (od), and reverse (n) according to whether the velocity is between zero and the input velocity, greater than the input velocity, or less than zero. note that a positive velocity is divided into d and od because there is usually a "direct drive" (dd) between them [hsieh and tsai, 1996]. if the output velocity ranges of an egt can be identified without specifying the gear sizes, a descending sequence of clutching conditions can be roughly configured. this will effectively facilitate the enumeration of all the feasible clutching sequences of an egt. 3.2 procedure for enumeration of clutching sequences an egt can provide several velocities depending on the assignment of the input, output, and fixed links. these various velocities need to be estimated and arranged in a descending order to arrive at a proper clutching sequence. in a transmission mechanism, usually the output link is permanently attached to a final reduction unit, and the change of velocity is accomplished by switching either the fixed link or the input link [hsieh,1996]. to a predetermined output link, o, choose two coaxial links (x, y), from the egt at a time to construct the clutching sequence nomograph. for an egm with m coaxial links, there is (m1)! /2 possible sets of two coaxial links. by taking one of the two coaxial links as the common input link the other as the fixed link and by drawing a line through them, two output velocities are obtained at a time: a total of (m-1)! velocities. the ends of each line are labeled with b al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 and c to denote a band clutch on the line of zeros and a rotating clutch on the line of the input velocity. perform this operation as many times as possible until all possible arrangements of (x, y, o) are exhausted. in the present methodology the velocities are arranged automatically in a descending order into three kinds: d, od and n. returning to our design example, the simpson gear train, because there are four coaxial links in this mechanism and link two is pre-assigned as the output link, this mechanism can provide six clutching conditions. figure 8 shows the clutching sequence nomograph for this mechanism. in arranging a clutching sequence, it is highly desirable to achieve a single-shift transition [hsieh, and tsai, 1998]. in order to achieve single-shift transitions, the d-velocities can be further classified into two sets as shown in fig. 9. a direct drive is obtained by simultaneously clutching two coaxial links of an egt to the input power source. a reverse drive can be obtained by applying one or two of the clutches designed for the forward drives for the reverse drive. as a result, we obtain two descending sequences of velocities as shown in figures 9(a) and (b), which result in two three-velocity and two four-velocity clutching sequences as shown in tables 2(a) through (d). table 2 (c) shows one feasible clutching sequence with rotating clutches attached to links 3 and 4, and band clutches attached to links 1 and 3. this clutching sequence has been applied in most threevelocity automatic transmission. figure 1 shows the functional representation of this three-velocity clutching sequence for the second reduction set. from fig. 9 (b), the velocity ratios can be written for threeor four-velocity automatic transmission as 12 2212 1 3,62,5 2,53,54,63,62,51 4,2d 1 )( rr nn nnnnn (30) 1 1 1 3,6 4,63 4 ,2d 2 1rr n n (31) 2 2 11 2,5 3,51 ,23n rr n n (32) 22 21 1 2,53,5 3,53 1,2od rr nn n (33) under certain clutch combinations the gear train may act as a rigid body, in which case the velocity ratio will equal to one ( 1r dd ), and the designer will not affect it by his selection of gear ratios. the other clutching sequences obtained are in agreement with those reported in the literature [chatterjee and tsai,1995,1996], except that there is no need to any information containing the approximate gear sizes arranged in a descending order that is required in other methods. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 4. optimization technique and problem formation in the systematic creation of mechanisms the functional evaluation stage deals with the selection of acceptable mechanisms from the enumerated list of mechanisms, in order to satisfy the functional requirements. the next stage in the creation of mechanisms is its design and analysis. in this stage dimensional synthesis techniques are used to determine the mechanism's proportions. the designer has to choose a gear train with a set of clutches that are to be operated in a chosen sequence, and a set of gear ratios that will provide a set of velocity ratios. the classical approach of finding proper gear ratios has been to choose a gear train and a corresponding clutching sequence, and then to vary the gear ratios by trial and error until the best possible velocity ratios are obtained. to eliminate trail and error, an objective function f is defined in terms of the velocity ratios kr for the gear train, the minimization of which ensures that the best possible gear ratios are achieved, subjected to certain constraints. the objective function can be written as 2 1 )1()( k i di i r r rf (34) where ir ; is the thi velocity ratio parameter obtained by the minimization process and dir is the thi desired velocity ratio. the velocity ratios krrr .........2,1 depend on the clutch selection and the topology of the gear train. it should be realized that for an arbitrary combination of dir there may not be a set of solutions for the gear ratios ijn , that satisfy the velocity ratio equations. in other words, the ideal minimum value of the objective function f(r) 0 may or may not be achievable. the constraints under which the function f(r) is minimized are now determined. 4.1. geometric constraints let id be the diameter of a gear element i. if the diametral pitch p of all the gears is the same, then ii zpd . and we can get the geometric constraints for the simpson gear train from fig. 1 as 634 21 ddd or 634 21 zzz and therefore, 26364 1 zzzz thus 2 11 13,64,6 nn (35) and in a similar manner 2 11 23,52,5 nn (36) note that both 13,6n and 23,5n are negative numbers since they correspond to external gear meshes. 4.2. kinematic constraints the kinematic constraints are determined from the system nomograph shown in fig.9. they are rewritten here as al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 22,5n (37) 023,5n (38) 10 4,6n (39) 013,6n (40) 5. constrained optimization using matlab's fmincon matlab provides the command (fmincon) for constrained minimization of an objective function f(x). fmincon finds a vector x that is a local minimum to a scalar function f(x) of several variables subject to constraints on the allowable x starting at an initial estimate[brian, 2007]. this is generally referred to as constrained nonlinear optimization. it finds a minimum of a constrained nonlinear multivariable function )(min xf x , subjected to one or more of the following constraints: c(x) 0, ceq(x) = 0, a·x b, aeq·x = beq, l x u. where x, b, beq, lb, and ub are vectors, a and aeq are matrices, c(x) and ceq(x) are functions that return vectors, and f(x) is a function that returns a scalar. f(x), c(x), and ceq(x) can be nonlinear functions. the objective function must be coded in a function file. in this work this file is called simpson and saved as simpson.m in the working directory. without any extra options, fmincon with linear inequality and equality constraints, lower and upper bounds, and nonlinear inequality and equality constraints is called as follows: [x,fval]=fmincon(@simpson,x0,a,b,aeq,beq,lb,ub,'constraint') the last input argument in this call is the name of a function file (denoted constraint in this work and saved as simpson_confun.m in the working directory), in which the nonlinear constraints are coded. 5.1. constraint function file: simpson_confun.m is a function file (any name can be chosen) in which both the inequality functions c(x) and the equality constraints ceq(x) are coded and provided in the form of column vectors. the function call [c,ceq]=constraint(x) must retrieve c(x) and ceq(x) for given input vector x. if only equality constraints are given, define c = [ ]. 5.2. interpretation: the retrieved ceq (x) is interpreted by fmincon as equality constraint ceq(x) = 0. the inequalities associated with c(x) are interpreted as c(x) 0. thus, if a constraint of the form c(x) 0 is given, rewrite this as -c(x) 0 and code -c(x) in the constraint function file. 5.3. placeholders: as shown above, the constraints have to be passed to fmincon in the following order: 1. linear inequality constraints, 2. linear equality constraints, 3. lower bounds, 4. upper bounds, and 5. nonlinear constraints 6. if a certain constraint is required, all other constraints appearing before it have to be inputted as well, even if they are not required in the problem. if this is the case, their input argument is replaced by the placeholder [ ] (empty input). al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 6. optimization results the designer initially specifies the gear train, enumerates the clutching sequence and then specifies the reduction ratios to be achieved. the optimization problem starts at an arbitrary design point and at the end of its execution displays the optimized gear ratios. results of sample inputs for the threevelocity simpson gear train are shown in table 3. the trial and error approach of finding the gear ratios for an automotive gear train to obtain a set of velocity ratios has been eliminated by formulating the task as a constrained nonlinear optimization problem. the optimization procedure was successfully applied to find those gear ratios for which the velocity ratios are closest to the original specification. the theoretical results are in complete agreement with the practical applications as shown in columns 2 and 3 in table 3. the optimized gear ratios shown in the last column of table 3 satisfy the geometric and kinematic constraints given by eqs. (35) through (40). figure 10 shows a matlab plot to the optimization results given in appendix b for ford c4, c5 and c6 simpson gear train given in the first row of table 3. references [1]arora, s. j., 2004, "introduction to optimum design". elsevier/academic press, amsterdam. [2]buchsbaum, f., and freudenstein, f., 1970, "synthesis of kinematic structure of geared kinematic chains and other mechanisms," journal of mechanisms and machine theory, 5, pp. 357-392. [3]brian d. hahn and daniel t. valentine, third edition 2007, "essential matlab® for engineers and scientists", elsevier, amsterdam. [4]chatterjee, g., and tsai, l. w. , 1995 , " enumeration of epicyclic-type transmission gear trains, " transactions of sae, vol. 103, sec. 6, paper no. 941012, pp. 1415-1426. [5]chatterjee, g., and tsai, l. w. , 1996 , " computer-aided sketching of epicyclic-type automatic transmission gear trains , " transactions of the asme, journal of mechanical design, , vol. 108, no. 3, pp. 405-411, september. [6]esmail, e.l., 2007, "kinematic nomographs of epicyclic-type transmission mechanisms, emirates journal for engineering research, volume 12, issue 3, pp. 47-55. [7]esmail, e. l. , 2008 "nomographs for enumeration of clutching sequences associated with epicyclic type automatic transmission mechanisms", asme international mechanical engineering congress and exposition (imece08), october 31november 6, 2008 boston, massachusetts, usa, paper no.66409. [8]hsieh,h.i., and tsai, l. w. , 1996, "kinematic analysis of epicyclic-type transmission mechanisms using the concept of fundamental geared entities", transaction of the asme, 118, pp. 294-299. [9]hsieh, h. i.,1996, "enumeration and selection of clutching sequences associated with epicyclic type transmission mechanisms", ph.d. thesis, department of mechanical engineering, university of maryland at college park, maryland, usa. [10]hsieh, h. l., and tsai, l. w., 1998, "the selection of a most efficient clutching sequence associated with automatic transmission," asme j. of mechanical design, 120, pp. 514-519. [11] http://transmissions101.com/automatic-transmissions.php al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 [12] http://www.vibratesoftware.com/html_help/html/gm/gm_transmissions.htm [13]mogalapalli, s.n., magrab, e.b. and tsai, l-w, 1993, "a cad system for the optimization of gear ratios for automotive automatic transmissions", sae paper, no. 930675. (http://papers.sae.org/930675) [14]tsai, l. w., 2001, "mechanism design: enumeration of kinematic structures according to function", crc press, boca raton, fl. table 1 clutching sequence of the mechanism shown in figure 1. activated clutches range c1 c2 b1 b2 first x4 x1 second x4 x3 third x4 x3 reverse x3 x1 table 2 (a) three-velocity clutching sequence for the first reduction set. activated clutches range c1 c2 b1 b2 first x3 x4 second x1 x4 third x3 x1 reverse x3 x1 table 2 (b) four-velocity clutching sequence for the first reduction set. activated clutches range c1 c2 b1 b2 b3 first x3 x4 second x1 x4 third x3 x1 fourth x1 x3 reverse x3 x1 table 2 (c) three-velocity clutching sequence for the second reduction set. activated clutches range c1 c2 b1 b2 first x4 x1 second x4 x3 third x4 x3 reverse x3 x1 table 2 (d) four-velocity clutching sequence for the second reduction set. activated clutches range c1 c2 c3 b1 b2 first x4 x1 second x4 x3 third x4 x1 fourth x1 x3 reverse x3 x1 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 table 3 table of optimized gear ratios for sample inputs for simpson gear train. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 1: a typical transmission mechanism. figure 2: a basic epicyclic gear train. figure 3: nomograph for the basic epicyclic gear train. figure 4: unification of fges and/or subsystems. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 5: unification of two fge nomographs into one nomograph. (a) nomograph unification of the two fges of the simpson gear train shown in fig. 1. (b) unified system nomograph figure 6: system nomograph of the simpson gear train shown in fig. 1. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 7: basic form of the clutching sequence nomograph for the simpson gear train. figure 8: clutching sequence nomograph for the simpson gear train. (a) first reduction set. (b) second reduction set. figure 9: clutching sequence nomographs for the two reduction sets of simpson gear train. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 10: example of matlab plot to the optimization results given in appendix b. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 appendix a: (1) matlab objective function m.file (simpson.m) function f = simpson(x) r1=(x(1)*x(2)+(x(3)-x(2))*x(4))/(x(1)*x(2));r2=1-(x(4)/x(1));r3 = 1;r4=(x(3)/x(2)); k1 = 2.8401; k2 = 1.6; k3 = 1.0; k4 = -2.0666; % ford c4, c5, and c6 f=((r1/k1)-1)^2+((r2/k2)-1)^2+((r3/k3)-1)^2+((r4/k4)-1)^2; (2) matlab nonlinear constraints m.file (simpson_confun.m) function [c, ceq] = simpson_confun(x) c=[]; ceq = [(1/x(2))+(1/x(3))-2; (1/x(1))+(1/x(4))-2]; (3) matlab optimization m.file (simpson_main_file.m) function [x,fval,exitflag,output,lambda,grad,hessian] = simpson_main_file(x0,lb,ub) x0 = [0,0,0,0] lb = [-inf,0,-inf,0] ub = [0,1,0,1] k1 = 2.8401; k2 = 1.6; k3 = 1.0; k4 = -2.0666; % ford c4, c5, and c6 options = optimset; options = optimset(options,'display' ,'iter'); options = optimset(options,'plotfcns' ,{ @optimplotx @optimplotfunccount @optimplotfval @optimplotconstrviolation @optimplotstepsize @optimplotfirstorderopt }); options = optimset(options,'algorithm' ,'interior-point'); options = optimset(options,'diagnostics' ,'on'); [x,fval,exitflag,output,lambda,grad,hessian] = ... fmincon(@simpson,x0,[],[],[],[],lb,ub,@simpson_confun,options); r1=(x(1)*x(2)+(x(3)-x(2))*x(4))/(x(1)*x(2));r2=1-(x(4)/x(1));r3 = 1;r4=(x(3)/x(2)); desired_velocity_ratios_k=[k1 k2 k3 k4] optimal_velocity_ratios_r=[r1 r2 r3 r4] gear_ratios_r=[x(1) x(2) x(3) x(4)] appendix b: matlab optimization results sample x0 = 0 0 0 0 lb = -inf 0 -inf 0 ub = 0 1 0 1 diagnostic information number of variables: 4 functions objective simpson gradient: finite-differencing hessian: finite-differencing (or quasi-newton) nonlinear constraints: simpson_confun gradient of nonlinear constraints: finite-differencing constraints number of nonlinear inequality constraints: 0 number of nonlinear equality constraints: 2 number of linear inequality constraints: 0 number of linear equality constraints: 0 number of lower bound constraints: 2 number of upper bound constraints: 4 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 algorithm selected interior-point end diagnostic information first-order norm of iter f-count f(x) feasibility optimality step 0 9 3.086034e-002 7.879e-001 4.395e-002 1 14 5.703720e-001 3.569e-001 6.575e+000 2.412e-001 2 19 1.143033e-001 1.785e-001 3.634e-001 4.008e-001 3 24 1.087254e-001 1.280e-002 4.185e-001 6.795e-002 4 29 9.720484e-002 2.355e-003 1.889e-001 5.592e-002 5 35 6.278506e-002 3.704e-003 1.538e-001 1.814e-001 6 40 5.691928e-002 1.242e-003 1.000e-001 2.678e-002 7 47 1.933844e-002 8.514e-002 3.016e-001 1.861e-001 8 52 6.567615e-003 2.740e-002 7.239e-001 1.112e-001 9 60 5.065902e-003 2.492e-002 5.317e-001 3.185e-002 10 65 3.090380e-003 2.568e-003 2.023e-002 2.931e-002 11 71 9.384946e-005 2.126e-003 5.481e-002 7.282e-002 12 77 2.879866e-004 2.381e-006 3.371e-002 1.913e-002 13 83 1.735759e-004 1.001e-007 4.000e-003 5.889e-003 14 88 7.257730e-007 1.938e-003 8.343e-003 1.697e-002 15 93 7.319344e-006 4.473e-005 8.000e-004 2.669e-003 16 98 2.539741e-008 9.698e-005 1.908e-003 3.645e-003 17 103 1.993598e-009 6.574e-008 1.033e-004 1.585e-004 18 108 1.243654e-009 1.522e-009 8.189e-006 2.435e-005 19 113 1.243537e-009 2.531e-014 8.000e-006 8.416e-008 20 118 6.036931e-010 5.857e-009 1.981e-006 2.867e-005 21 123 6.074269e-010 2.042e-012 1.600e-006 5.229e-007 22 128 5.819850e-010 3.450e-010 4.557e-008 6.968e-006 optimization terminated: first-order optimality relative error less than options. tolfun, and relative constraint violation less than options.tolcon. desired_velocity_ratios_k = 2.8401 1.6000 1.0000 -2.0666 optimal_velocity_ratios_r = 2.8401 1.6000 1.0000 -2.0666 gear_ratios_r = -0.3333 0.2581 -0.5333 0.2000 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 932 viscoelastic response of the thorax under dynamic loading asst. prof. dr. mohsin noori hamzah machines & equipment engineering department university of technology, iraq dr.mohsin@uotechnology.edu.iq received 6 may 2014 accepted 5 jun 2014 abstract in this paper, the contribution and constitutive modelling of the intercostal muscles (icm) in a computational thorax fe model is studied. this helps in improving our knowledge to predict the number and locations of the fractured ribs during automotive accidents. icm demonstrates a number of complex features including nonlinearity, viscoelasticity, and anisotropy. these muscles consist of an external and an internal layer, each of them having its own fiber orientation. tensile tests were performed on icm samples harvested from one cadaver. each specimen consisted of a 15 mm-long rectangle of icm connected to the adjacent superior and inferior sections of the ribs. the load and applied displacement were measured. an optical system (aramis) was used to measure the strain field on the external layer. preconditioning, ramp and hold (relaxation), and quasi-static failure tests were performed. the hyperelastic material parameters were estimated through an optimization process based on the experimental force–displacement curves of the quasi-static tensile tests. the results of the parameters optimization revealed that the icm exhibited a high degree of anisotropy. the identification of the viscoelastic parameters was accomplished from the ramp and hold (relaxation) tests using prony series. keywords: anisotropic hyperelastic materials, fiber orientations, intercostal muscles, image correlation تحت تأثير االحمال الديناميكيةاللزجة نةاستجابة الصدر المر الخالصة باستخدام العناصر المحددة. للصدر الرقميالحسابي نموذجفي ال الوربيةعضالت النمذجة و مساهمة في هذا البحث دراسةتم الوربيةعضالت . تملك الالسيارات حوادث أثناء المكسورة األضالع ومواقع لتنبؤ بعددل معرفتنا في تحسين وهذا يساعد طبقة من هذه العضالت تتألف خصائصها مع تغير االتجاه. باينتتو، خطي، لزجةخصائص معقدة، حيث ان تصرفها ال .خاصة به ليافاتجاه ا ولكل منها، داخلية واخرى خارجي الوربيةعضالت المم من 15 من مستطيل بطولوتألفت كل عينة بشرية. وربيةعضالت لختبارات عل عينات دد االأجريت استخدام واالستطاالت الناتجة اثناء االختبار. كما تم تم قياس الحمل .المجاورة (المقطوعة)يا يا والدنعلمع األضالع المتصلة ، االسترخاءاختبارات مسبقة، ال اختبارات التهيئةأجريت .عل الطبقة الخارجية توزيع االنفعاللقياس (أراميس)نظام بصري عل جميع العينات. ثابتال-واختبارات الفشل دبه mailto:dr.mohsin@uotechnology.edu.iq al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 الشد الختبارات االزاحة -اعتمادا عل منحنيات القوة الحل االمثلمن خالل عملية المرونة-ةمفرطالمات المواد معل خمنت أظهرت النتائج بان العضالت الوربية تملك درجة عالية من التباين في الخواص. اما المعلمات الخاصة بالتصرف .ثابتال-دبه .باستخدام سلسلة برونيرات االسترخاء حسابها عل أساس اختبا اللزج للمادة فقد تم 1. introduction the increase in road traffic accidents contribute to higher rates of injuries resulting from seat belt use. chest and/or abdominal abrasion at the site of seat belt contact are commonly seen, and with the exception of subcutaneous bruising, the sternal and ribs fracture is the most common seat belt injury. therefore, the prediction of rib fractures using a computational thorax model remains an important and elusive challenge, as the finite element (fe) currently models generally fail to match both the number and the location of the fractures reported during experimental tests. although a large body of research dealing with the thorax injury tolerance, the available thorax fe models are still missing to include the contribution of the intercostal muscles (icm). several models have been developed to model the response of the chest or the entire body under a variety of loading conditions [1]-[6], based on the work performed to determine the material properties of various isolated thoracic components, including clavicles [7], ribs [8]-[9] and costal cartilage [10]-[11]. the contribution of the intercostal muscles, in modelling the thorax, received, relatively, little attention [12], besides, very little work on the constitutive modeling of intercostal muscles [12]. finite element modeling facilitates the simulation of thoracic impacts using a wide variety of boundary conditions, material properties and other variables than would not be possible to evaluate experimentally due to cost, material availability, instrumentation limitations or physical constraints. fe modeling of the thorax helps to improve the understanding of the injury mechanisms in the ribs, and consequently more accurate fe models that account for the contribution of each anatomical component of the thorax are expected to improve injury prediction capabilities. while the contribution of the bony structure is well quite well understood in injury biomechanics, the role of the soft tissue such as the icm in the chest deformation has yet to be quantified. the icm are located in the intercostal space and help to expand and shrink the size of the chest cavity during breathing. they are made of three layers named external, internal and innermost layers or intercostal muscles. the internal icm, located inside the ribcage, extend from the front of the ribs and go around back, past the bend in the ribs. the external icm, located outside the ribcage, wrap around from the back of the rib almost to the end of the bony part of the rib in front. the fibers in the external and internal layers are orientated diagonally with respect to the ribs, and run in opposite directions. icm demonstrate a number of complex features including nonlinearity, incompressibility, viscoelasticity and anisotropy that are not yet well described [12]. global human body models consortium, ghbmc, a project that try to maintain and make available human body models on a wide scale basis for purposes of improving human safety by allowing mathematical assessments of possible real world injury conditions. mathematical human body modeling analysis can enable assessment of more real world injury scenarios to allow for engineering improvements to help prevent potential human injury. trying to use this promising project (ghbmc) in modelling the side impact of leport et al [13], we found that this project is missing to include a realistic constitutive modelling of the icm. the available model in this project is a simplified model that allow to put only an approximate modulus of elasticity, however, trying to use this project by using different values of elasticity modules gave different estimates of the number and location of fractured ribs, figure 1. the conclusion is that intercostal muscles are very important in the fe modelling of the thorax. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 the objective of this paper was to introduce an experimental and theoretical analysis to quantify the effect of the fiber orientation on the mechanical response of the icm. tensile tests were performed on icm samples harvested on one post-mortem human subject, and an optical system was used to measure the strain field on the external layer. next, a theoretical framework was outlined to develop a constitutive model of the icm based on an optimization scheme for determining the material parameters. 2. experimental work three specimens of intercostal muscles were extracted from one post-mortem human subject (70 year old, 160 cm tall, 60 kg): one sample (#a) located between ribs 8 and 9 from the anterior aspect of the rib cage, and two samples (#b and #c) located between ribs 9 and 10 in the lateral and posterior aspects of the rib cage (figure 2). the dimensions of the icm specimens are detailed in table 1. each sample consisted of rectangles of icm connected to the adjacent superior and inferior sections of rib, and included the entire depth of the muscle wall and the soft tissue (parietal pleura) attached to the internal surface of the icm (figure 2). prior to their excision, the two rib sections were connected to a wire of copper that maintained their relative position. once harvested, the angle of the muscle fibers with respect to the inferior rib was measured for the internal and external layers, and the rib sections were potted in blocks (approx. 50 mm × 50 mm × 25 mm deep) of fast cast® casting resin (goldenwest manufacturing, inc.). prior to testing, each of the specimens was soaked in body temperature (37 c) saline solution for about 2 hours, to allow them to rehydrate if needed. this soaking step was shown to be effective to maintain the tissue in good condition [11], as the tests were performed in open air at room temperature. after this soaking time, each specimen was removed from the soaking solution and the surface was patted dry. the anterior surface of the specimen (i.e. the icm outer layer) was then covered with a black and white speckle pattern. an optical system was used to measure the strain during the experiment: the deformation of the painted surface was recorded with two high-speed cameras (nac-gx1) at 2,000 frames per second, with a resolution of 1280×1024 pixels. prior to recording the images, the two cameras were affixed to a rigid bar, and their orientation was adjusted so that (1) the center of the field of view of each camera was confounded in the focus plane and (2) the angle between the cameras was around 20 degrees (fig. 3). the two-camera system was then calibrated so that the surface displacement and strain fields could be calculated with the aramis software package (version 6.2.0, gom-optical measuring techniques, germany). the block containing the inferior rib (inferior block) was connected to a 6-axis load cell, while the superior block was connected to the extremity of the piston of an instron material tests machine (model 8874). once the sample was in position, the copper wire was cut. each specimen was subjected to a series of three tensile tests. first, each specimen was subjected to a pre-conditioning test imposing a 1 hz, cyclical (sinusoidal) displacement in tension (no compression) for 20 cycles. the magnitude of the displacement was 5% of the initial length of the muscle. afterwards, the test machine was reset to the initial (pre-test) specimen position. then, each specimen was subjected to a tensile dynamic ramp-hold test. a displacement was applied via a 300 mm/s ramp. the magnitude of the displacement was 25% of the initial length of the specimen. after the ramp this position was held for 60 s to observe force relaxation in the specimens. afterwards, the test machine was again reset to the initial (pre-test) specimen position. finally, each specimen was subjected to a tensile quasi-static failure test, where a 3 mm/s displacement was applied past the point of failure of the specimen. the applied displacement and the load were recorded with a dewetron (dewe-2010 series, dewetron, graz) data acquisition system. for the quasi-static failure tests data were collected at a rate of 10 khz. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 949 the entire test matrix was provided for completeness, however only the results of the quasi-static failure tests were used in the current study. 3. constitutive modeling the intercostal muscles under consideration is assumed to be an anisotropic hyperelastic and continuous solid, which is described by the coordinate system x in undeformed state. after deformation the solid is described by the coordinate system x. the deformation gradient, f, is defined as , and the volume ratio, j, as | | . the deformation gradient can be decomposed into volumetric and distortional deformation, ( ) ̅. similarly, for the right cauchy-green tensor can be defined as: ( ) ̅ ̅ ̅ ̅ (1) the helmholtz free energy, is decoupled into the volumetric and isochoric parts. furthermore, the isochoric part can be divided into an isotropic (independent of fiber orientations) and an anisotropic part: ( ) ( ̅) ( ̅ ) (2) where and are two fiber directions in the undeformed configuration (fig. 4) that characterizes the anisotropic behavior of the material, with | | | | . the isochoric part (isotropic and anisotropic parts) of the strain energy functions can be written in terms of strain invariants and pseudo-invariants: the isotropic part can be written in terms of the strain invariant ̅ ̅, while the anisotropic part can be written in terms of pseudoinvariants, which for two families of fibers are ̅ ̅ ̅ ̅ ̅ [14]. in the current study, we use only ̅ and ̅, since they are the squares of the stretches in the directions of the fibers, and therefore have a physical interpretation [15]. the strain energy in terms of the modified invariants is: ( ) ( ̅ ̅) ( ̅ ̅) (3) where ̅ ̅, ̅ (( ̅) ̅ ), ̅ ̅ , and ̅ ̅ . the volumetric part of the strain energy function is given by ( ) ( ) (4) the isotropic part of the strain energy function used in this work as a polynomial form, expressed as: ( ̅ ̅) ∑ ( ̅ ) ∑ ( ̅ ) (5) while the anisotropic part of the strain energy function, that is to say the energy function in the fibers, is assumed in the form of an exponential form: al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 943 ( ̅ ̅) [ ( ( ̅ ) )] [ ( ( ̅ ) )] (6) in order to determine the constitutive equations for anisotropic hyperelastic materials in term of strain invariants, the strain energy function, is differentiated with respect to the tensor c. by means of the chain rule, the second piola-kirchhoff (2 nd pk) stress, , can be decomposed into the volumetric and the deviatoric stresses: (7) where and are the volumetric and the deviatoric stresses, respectively, which in turn can be expressed as: , (8) ( ̃ ( ̅ ̃) ̅ ) (9) and, ̃ ̅ ∑ ̅ ̅ ̅ (10) the derivatives of the modified invariants with respect to the deviatoric part of the right cauchygreen tensor are written as: ̅ ̅ ̅ ̅ ̅ ̅ ̅ ̅ ̅ ̅ (11a) and the derivatives of the deviatoric part of the strain energy function with respect to the modified strain invariants are: ̅ ( ̅ ) ( ̅ ) ̅ ( ̅ ) ( ̅ ) ̅ ( ̅ ) ( ( ̅ ) ) ̅ ( ̅ ) ( ( ̅ ) ) (11b) the cauchy (true) stress can be computed from the 2 nd pk: (12) for uniaxial tension, assuming full incompressibility, i.e., j=1, and, , the deformation gradient becomes: [ ] al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 944 defining the fiber orientation vectors as { } and { }, equations (11a) yields to (for uniaxial tension): ̅ ̅ ̅ ̅ [ ] ̅ ̅ [ ( ) ( ) ( ) ( ) ( ) ( ) ] ̅ ̅ [ ( ) ( ) ( ) ( ) ( ) ( ) ] where and are the angles of the external and internal intercostal muscles fibers, respectively, measured counterclockwise from direction 1-axis (fig. 4). combining the above equations with equation (7) yields to: [ ] [ ] [ ̃ ̃ ̃ ̃ ̃ ̃ ̃ ̃ ̃ ] ̃ ( ̃ ̃ ) [ ] (13) since the stresses along directions 2 and 3 (figure 4) are zero in the case of the uniaxial test, an expression for the hydrostatic pressure can be obtained from equation (13). then substituting the expression obtained for the hydrostatic pressure for the stress in 1-axis yields to the following constitutive relation: ̃ ̃ (14) where; ̃ [ ( ̅ ) ( ̅ ) ] [ ( ̅ ) ( ̅ ) ]( ) [ ( ̅ ) ( ( ̅ ) )] ( ) [ ( ̅ ) ( ( ̅ ) )] ( ) ̃ [ ( ̅ ) ( ̅ ) ] [ ( ̅ ) ( ̅ ) ]( ) the material parameters , , , , and are related to the isotropic part of the muscles response (the matrix), while are related to the anisotropic part (the fibers) of the response. all these parameters were estimated through an optimization process and an inverse fe approach. 4. viscoelastic modeling the viscoelastic behaviour of the icm is modeled via the relaxation function using a prony series. values of the shear and bulk modulus would be enough as the starting values of the al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 material properties over the time, which are representative of deviatoric and volumetric parts of the stress, respectively, as expressed in the following equations [14]: , (15) ∫ ( ) ∫ ( ) , (16) where is cauchy stress, e and are deviatoric parts of the strains, g(t) and k(t) are shear and bulk modulus functions, respectively, t and τ are current and past time, respectively, and i is identity matrix. relating to the shear and bulk modulus over the time, prony series can be proposed by the flowing formulas [14]: [ ∑ ( )] (17) [ ∑ ( )] (18) where superscript shows belonging to shear or bulk modulus, and subscript indices the number of series component, and are relaxation time constants for each prony series component. that can be calculated at t equal to zero will be obtained from equation (17) as, ∑ , it means that ∑ , so equation (17) can be written as : [ ∑ ] (19) there are only two constants and which should be determined by a relaxation test. in the series, the initial values of g and k would be taken into account at time equal to zero. for finding the coefficient of the bulk function, the same above procedure will be followed. 5. aramis aramis is a non-contact optical 3d deformation measuring system. aramis analyzes, calculates and documents deformations. the graphical representation of the measuring results provides an optimum understanding of the behavior of the measuring object. aramis recognizes the surface structure of the measuring object in digital camera images and allocates coordinates to the image pixels. the first image in the measuring project represents the undeformed state of the object, figure 5a. after or during the deformation of the measuring object, further images are recorded. then, aramis compares the digital images and calculates the displacement and deformation of the object characteristics. if the measuring object has only a few object characteristics, like it is the case with homogeneous surfaces, you need to prepare such surfaces by means of suitable methods, for example apply a stochastic color spray pattern. in the present work the outer layer surface of the intercostal muscles specimen was covered with a black and white speckle pattern. the deformation of the al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 painted surface was recorded with two high-speed cameras (nac-gx1) at 2,000 frames per second, with a resolution of 1280×1024 pixels. aramis observes the deformation of the specimen through the images by means of various square or rectangular facets. then, the deformation gradient tensor, f, is calculated from tracking these images. subsequently, the strain values or vector can be calculated. 6. results 6.1 tensile tests the stress and stretch were obtained from the force and displacement: the stress was defined as the force to initial average cross section ratio, and the stretch as the displacement to initial average length ratio using the dimensions of the samples presented in table 1. for the three samples (figure 6), a toe region was observed, followed by quasi-linear response after about 20 % of stretch. the ramp-hold tests (or relaxation test) is shown in fgiure 7 for sample a, the data are processed and filtered with matlab. it is seen from the figure that there is an initial overshoot, after that the muscles relaxed quickly at the first few seconds, then, the relaxation rate slow down to reach a flat situation. 6.2 fiber orientation the angles of the internal and external fibers for all specimens were measured experimentally, table 2, the measurements was from the lower ribs in counter-clockwise direction. 6.3 determination of material parameters material parameters were adjusted using the matlab ™ optimization toolbox version 7.11 (the mathworks inc.). based on the information of the fiber orientation presented in table 2, a fitting of the experimental data from the uniaxial tests was implemented using the levenberg– marquardt algorithm to solve the nonlinear curve fitting in the least squares sense. the materials parameters obtained from the optimization process with 95% confidence bounds for the three tested icm samples are summarized in table 3. 7. finite element modeling after calculating the material parameters using the matlab ™ optimization toolbox, the fe analysis was conducted using the ansys apdl software package (ansys, inc.). the problem was solved as a 3-d solid, meshed with high order 3-d 20-node solid element with quadratic displacement interpolation (solid186 in ansys). the nlgeom command, for nonlinear geometry solution option, was also enabled. finally, the apdl command tb-ahyper was invoked: this command enables the modeling of anisotropic hyperelastic materials based on the definition of a potential-based-function with parameters that define the volumetric part and the isochoric part (the matrix and the fiber directions). once the mesh was created, the hyperelastic parameters were initialized based on the results obtained from matlab. in order to demonstrate the effect of the fiber orientation on the icm response, i.e. the anisotropic behavior of the muscles, the problem was first solved for sample a as an isotropic hyperelastic one, assuming no fibrous structure. it was observed that the strain pattern was approximately symmetrical (fig. 8a). when anisotropy was assumed (fig. 8b), using fiber angles of 55° for the internal layer and 145° for the external layer, the strain field was found to be al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 unsymmetrical (fig. 8b) . this demonstrates that there is a significant difference in muscles response between the two assumptions. the same conclusion was drawn for samples b & c. 8. discussion 8.1 experimental results the icm exhibited a common soft tissue behavior with a toe region up to approximately 20 % where little stress is generated. samples b and c exhibited non-linearity for 1.42 and 1.57 of stretch ratios. the reasons behind these sudden drops (sample b-figure 6) of the stress are unclear. two assumptions can be made. first, this could be an experimental artifact: the strain analysis relies on a speckle pattern that was created with an oil-based paint that hardens when it dries, and the drop in the stress could have been caused when the paint cracked. indeed, because of the large deformation sustained by the icm sample, the paint cracked in several areas, when the deformation of the icm reached the paint failure threshold. the choice of paint was a tradeoff between its compliance and its ability to properly adhere to a humid surface. the second assumption is that damage occurred because of fiber decohesion or fracture. the modeling approach in the present study did not account for the damage or fracture, as this would have required to unload and load the sample several times identify the parameters for a damage evolution law. as only three samples were tested, it is not possible to draw extensive conclusions regarding the location dependence of the icm mechanical properties. however, it would make sense for the icm to have location dependent properties because the mass of the thorax is not equally distributed within the ribcage. 8.2 fiber orientation the assumption of isotropy may predict the stiffness and response for the muscles when subjected to the same boundary condition as that during experiments, it was shown that anisotropic modeling, i.e. including the contribution of the fibers, resulted in a more accurate estimate of the strain. indeed, the strain fields in the external layer of the icm were significantly different under these two assumptions. therefore, assuming an isotropy behavior prevents from accurately predicting the values and locations of the maximum stress during an impact, and consequently the simulation results could lead to the incorrect prediction of the number and location of the rib fractures, to ultimately yield to a wrong estimation of the risk incurred by a belted vehicle occupant during an impact. 8.3 material parameters the icm were assumed to behave as a hyperelastic anisotropic and incompressible soft tissue. they were assumed to be consisted of two families of fibers that were assumed to be straight. the response of the anisotropic part of the strain energy and the resulted constitutive relation was assumed to related to the fibers only, while the isotropic part was related to an effective matrix which includes the response of the innermost layer. at low strain, the isotropic part of the muscles (the matrix material) is the effective response, and as the strain increases the stiffening of the icm muscle occurs and the fiber response becomes the dominant response (the matrix material is significantly less stiff than the fibers). the response of the icm was found to be location dependent, as even neighboring samples (samples b & c) give different responses (figure 6). six material parameters ( , , , , and ) were used to describe the matrix material depending on the polynomial form of strain energy, while an exponential form of the strain energy function with two material parameters was used for each layer al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 ( ). all these parameters were estimated through an optimization process using matlab. the material parameters c1 and c2 were assumed to have the same numerical values as e1 and e2, respectively, and these parameters were constrained to be greater than zero to have some physical meaning (the fibers are assumed active only in extension). the fitting procedure developed in this study demonstrates the predictive ability of the current approach to estimate the anisotropic stiffening due to fiber reinforcement at large strains. 9. conclusions a constitutive model and an inverse fe analysis were developed to determine the anisotropic material properties of icm. in addition to matching the stress-strain relationship, the optimization scheme constrained the computational model to match the experimental strain measured in several locations of the icm external layer and compared with that obtained from the optical strain measurement system (aramis). the optimized model was then used to evaluate the effects of the anisotropic behavior of the muscles, i.e. the effect of fibers in each layer, on the predicted mechanical behavior. the fibers orientations for the three samples was found to vary from 145° to 155° for the external layers, and from 55° to 70° for the internal layers (the angles were measured locally from the lower rib in counter-clockwise direction). the fitting procedure demonstrated the ability of the proposed model to account for the anisotropic stiffening due to fibers reinforcement at large strains. it was shown that localization in the strain field was predicted by the computational model only when the icm was modeled as anisotropic. the results of the parameters optimization revealed that the icm exhibited a high degree of anisotropy. while including fiber orientation of the icm in a fe model of the thorax adds extra complexity to the model, the present study demonstrates that it may be a necessary step to properly match the effective stiffness of the icm. indeed, it is anticipated that a more accurate material model for the icm will contribute to a better prediction of the complex strain field in the rib cage that will ultimately lead to a better understanding of the injury mechanisms. acknowledgement the author would like to acknowledge university of virginia for their support and assistance with the experimental tests during his one-year sabbatical. references [1] lizee e, robin s, song e, bertholon n, lecoz jy, besnault b, lavaste f, development of a 3d finite element model of the human body, proc. 42nd stapp car crash conference, pp. 115-138, society of automotive engineers, warrendale, pa, 1998. [2] deng yc, kong w, ho h, “development of a finite element human thorax model for impact injury studies”, society of automotive engineers, 1999-01-0715, warrendale, pa, 1999. [3] robin s, humos: human model for safety—a joint effort towards the development of refined human-like car occupant models, proc. 17th enhanced safety of vehicles conference, paper 297, 2001. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 942 [4] shah cs, yang kh, hardy wn, wang k, king ai, development of a computer model to predict aortic rupture due to impact loading. stapp car crash journal, 45:161-182, 2001. [5] kimpara h, lee j, yang k, king a, iwamoto m, watanabe i, miki k, development of a three-dimensional finite element chest model for the 5th percentile female, stapp car crash journal, 49:251-269, 2005. [6] zhao j, narwani g, development of a human body finite element model for restraint system r & d application, proc. 19th international technical conference on experimental safety of vehicles, 2005. [7] duprey s, bruyere k, verriest j-p, influence of geometrical personalization on the simulation of clavicle fractures, j. biomechanics, 41:200-207, 2008. [8] charpail e, trosseille x, petit p, laporte s, lavaste f, vallancien g, characterization of phms ribs: a new test methodology, stapp car crash journal, 49:1-16, 2005. [9] kindig m, lau a, kent r, biomechanical response of ribs under quasistatic frontal loading, traffic injury prevention, 12(4):377-387, 2011. [10] lau a, oyen ml, kent rw, murakami d, torigaki, t, indentation stiffness of aging human costal cartilage, acta biomaterialia, 4:97-103, 2008. [11] forman j, del pozo de dios e, arregui dalmases c, kent r, the contribution of the perichondrium to the structural mechanical behavior of the costal-cartilage, j. biomech. engineering, 132(9):094501, 2010. [12] hamzah m, subit d, boruah s, forman j, crandall j, ito d, ejima s, kamiji k, and yasuki t, “an inverse finite element approach for estimating the fiber orientations in intercostal muscles” ircobi conference 2013, irc-13-88, sweden. [13] leport t, baudrit p, potier p, trosseille x, lecuyer e, vallan cien g, “study of rib fracture mechanisms based on the rib strain profiles in side and forward oblique impact”, 55th stapp car crash conference, 2011. [14] holzapfel ga, nonlinear solid mechanics: a continuum approach for engineering, john wiley & sons, 2000, england. [15] holzapfel ga and gasser tc, a new constitutive framework for arterial wall mechanics and a comparative study of material models, journal of elasticity, 61:1-48, 2000. table 1: dimensions of the icm specimens sample total length (mm) muscle length (mm) width (mm) thickness (mm) ant mid post ant post sup inf ant post a 40.0 41.6 43.4 17.1 16.3 30.0 28.0 4.3 4.7 b 50.0 52.5 53.1 21.2 19.0 28.9 28.3 2.8 2.3 c 52.2 51.6 49.3 18.1 15.3 29.0 29.0 2.5 4.4 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 922 table 2: icm fiber angles for internal and external layers, measured from the lower ribs. sample # angle of external layer angle of internal layer a 145° 55° b 147° 61° c 155° 69° table 3: materials parameters obtained from the optimization process for the icm samples sample material parameters for the icm samples & & r 2 a 0.02001 0.01980 3.0e-14 -0.0881 0.0199 -0.1167 0.3100 0.1901 0.978 b 1.42e-6 0.02000 8.2e-14 2.3e-11 0.0198 2.2e-14 0.2885 0.1999 0.981 c -0.0999 1.92e-6 0.1395 0.01297 6.0e-13 0.08071 0.2913 0.2002 0.995 figure 1. response of thorax using different values of elasticity modulus of icm by ghbmc. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 922 figure 2. dimensions and locations of the icm samples. figure 3. experimental testing and cameras set-up with lights. figure 4. intercostal muscles layers fibers orientations post mid ant sup inf length width sample b intercostal muscles sample c sample a instron base icm sample high-speed cameras (nac-gx1) rigidly attached to the camera bar 1 2 external internal innermost intercostal muscles 𝐚 𝐠 3 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 929 (a) speckle pattern (b) image at 10 % strain (c) image at 20 % strain figure 5. aramis speckle pattern and images correlation. figure 6. stress vs. stretch ratio for quasi-static tensile tests. 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.0 1.1 1.2 1.3 1.4 1.5 1.6 s tr e ss ( m p a ) stretch ratio al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 923 figure 7. ramp and test (relation test) for sample a. (a) (b) figure 7. effect of fiber orientations on the strain pattern in the icm for sample a, (a) isotropic assumption (no fibers effect), (b) anisotropic assumption (with fibers effect) 0 10 20 30 40 50 60 -5 0 5 10 15 20 25 30 35 time (s) f o rc e ( n ) icm_samp3_ramphold-fz-cfc1000 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 391 effect of double quenching on wear behavior for low carbon dual phase steel by khamaal muhsen kseer university of technology/ department of applied science abstract: in this paper the effect of double quenching heat treatment on microstructure and dry sliding wear behavior of low carbon dual phase steel with carbon concentration (0.0977% c) was investigated. the specimens were intercritically heat treated at different temperatures and then water-quenched. the martensite volume fraction in the double quenched specimens was higher than that of the single quenched specimens. hardness test was conducted on low carbon steel specimens using brinell hardness test. optical microscopy was employed to examine the microstructure of the specimens. wear test were carried out on the single and double quenched specimens under dry sliding wear condition using a pin-on-disk machine at different loads with constant sliding time and speed, and at different sliding time with constant loads and speed. the experimental results showed that the wear rate effectively decreased in the double quenched specimen. key words: dual phase steel, low carbon steel, wear test, double quenching, intercritical heat treatment. ورتاثير االخماد الثنائي على سلوك البلى للصلب واطيء الكربون ثنائي الط خمائل محسن كسير الجامعة التكنلوجية / قسم العلوم التطبيقية الخالصة تم دراسة تاثير االخماد الثنائي على البنية المجهرية والبلى االنزالقي الجاف للصلب واطيء في هذا البحث مادها بالماء . لقد وجد ( .تم معاملة العينات بدرجات حرارة مختلفة واخ%0.0977كربون )تركيز ذو ثنائي الطور الكربون رتنسايت اكبر في العينات التي اجري لها اخماد ثنائي من العينات التي اجري لها اخماد مرة اان مقدار الكسر الحجمي للم ان اختبار البنية المجهرية تم باستخدام ل لعينات الصلب الواطيء الكربون . يواحدة . كما تم اجراء اختبار صالدة برن . المجهر الضوئي al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 المسمار على تقنيةاجري اختبار البلى االنزالقي للعينات االخماد الثنائي والعينات المخمدة مرة واحدة باستخدام تحت ازمان انزالق مختلفة مع تثبيت كل كما تم االختبار احمال مختلفة و زمن انزالق وسرعة ثابتين , باستعمالالقرص نت ان معدل البلى قد قل بشكل واضح في العينات التي تم اجراءاالخماد الثنائي لها من الحمل والسرعة . النتائج العملية بي . introduction in most cases, failures of material initiate from the surface, and are sensitive to microstructure and properties of the surface [1]. wear is one of the important mechanical properties expected from steels in actual service condition for some of the aerospace and automobile parts [2], the best opportunities of the application for different elements of cars have the steels with a ferritic – martensitic structure. the dp-type (dual phase) steels have a structure of a ferritic matrix with islands of martensite [3]; the amount of martensite present in ferrite-martensite steel will depend on the intercritical annealing temperature in the ferrite plus austenite region. further increasing the volume fraction of martensite increases the strength of the dual phase material. unfortunately, increasing the martensite content might reduce ductility and toughness [4]; hence wear resistance increase with increasing ductility so the excess in martensite phase raises wear rate [5]. adamczyk and grajcar [3] investigated various routes of a heat treatment by using double quenching in order to obtain a dp-type structure with required fractions of ferrite and martensite and optimum mechanical properties of the investigated low-carbon steel and they concluded that various initial structure influences morphology of martensite in a final dp-type structure of the heat-treated steel. also güral et al. [5] studied the effect of double quenching on wear properties of atomized iron powder mixed with 0.3 % graphite and 1 % ni powders, the mixed powders were cold pressed and sintered at 1200°c for 30 min under pure ar gas atmosphere. they found that martensite volume fraction in the double quenched specimens was higher than that of the single quenched specimen and wear coefficient effectively decreased in the double quenched specimen. tekeli et al. [2] studied dry sliding wear behavior of fe + 0.3% graphite powder metallurgy processed (pm) steels. after wear tests it was seen that the wear rate of the intercritically annealed specimens was very low in comparison to as-sintered specimen. the specimen intercritically annealed at 728 °c showed the lowest wear rate, despite its lower martensite volume fraction. wang et al. [1] observed that the friction coefficient decreases and the wear resistance increases with the nanocrystalline (nc) surface layer. the improvement in friction and wear properties may be attributed to the harder nc surface layer which reduces the degree of plowing and micro-cutting under the lower load and the degree of plastic removal and surface fatigue fracture under the higher load, respectively. the aim of this paper is to use double quenching heat treatment in order to obtain a dp-type structure with required fractions of martensite and optimum wear properties of the investigated low-carbon steel. experimental procedure 1. material and heat treatment the chemical composition of the investigated low-carbon steel was carried out at alnaser company for mechanical industry / ministry of industry and minerals by using spectroscopy method (table 1). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 391 the established heat treatment conditions are schematically shown in (table 2), respectively all samples are tempered at temperature 200°c for one hour after heat treatment. 2. microscopy characteristics the microstructure of the surface layer on the investigated low-carbon steel characterized by optical microscope, the specimens were grinded by using aluminum oxide paper lubricated with water (600, 800, 1000, and 1200) grit, the samples polished by alumina suspension then etched with the 2% nital solution. mean linear intercept method was used for the calculation of martensite volume fraction according to the astm e562 [6]. 3. hardness test hardness test was achieved by using brinell hardness test. the specimens were grinded by using aluminum oxide paper lubricated with water, ball diameter of the tester was 2.5 mm, and the applied load was 187.5 kgf. hardness values were calculated using brinell hardness equation [7]. 4. wear test unlubricated wear experiment were performed under ambient laboratory conditions using a pin -ondisc wear tester, where the pin is loaded normally. the variables which are used for wear test can be presented by: 1study the effect of normal load on wear rate by using load (10, 20 and 30) n at both constant sliding time 20 min and constant speed. 2study the effect of the sliding time on wear rate by using times (10, 20 and 30) min at constant normal load 2n and constant speed .wear rate can be calculating by using the followed equation: )1( 2 tnr w rw    where: w = weight difference of the sample (gm) , 21 www  . rnt2 = sliding distance (cm). r = radius from sample centre to the disc centre (cm) . n = disc rotational speed = 500 r.p.m. t = test time (min). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 resultes & discussion 1. microstructure characteristics the specimens have a ferritic matrix and the martensite is located on boundaries of α phase as a network (figs.3 & 4) or as islands (figs. 1, 2, 5&6). the location of martensite is strongly dependent on a distribution of the austenite formed due to a carbon enrichment of the boundary-zones of ferrite connected with a decomposition of pearlite grains [3]. during the heat treatment of the investigated steel the privileged diffusion of carbon on the boundaries of the α phase is occurred, an increasing in heat treatment temperature leads to the increase of martensite volume fraction, keeping the distribution of this phase on grain boundaries of the α phase [3]. the diversity in morphology of the structure was the specimens quenched twice. in this case, during heating the steel the nucleation of austenite mainly occurs on the boundaries of martensite laths formed after primary quenching of the investigated steel from a temperature of 900°c [3]. the predominated martensite fraction occurs mainly as islands located in surroundings of grain boundaries of ferrite grains (figs. 1, 2,5and 6). moreover, in surroundings of martensite, especially at a boundary zone of large grains of the α phase, small grains of the recrystallized ferrite can be identified. they are a result of plastic deformation connected with volume changes accompanying the martensite transformation [3]. apart from the morphology differences after the heat treatment of steel according to the route 1 the difference in a grain size of ferrite is observed. the more fine-grained structure has steel heat-treated according to the route 1. this is due to the increased number of places convenient for the nucleation of ferrite and also a partially course of the recrystallization of the specimens with an initial structure of martensite [3]. optical micrographs reveal that the coarse martensite was obtained with further increase in martensite volume fraction for specimens of the investigated steel. the increasing in temperature of heat treatment leads in increasing of volume fraction of the martensite (mvf) [2, 3, and 8] as shown in (table 3) . 2. hardness test it appears from (table 4) that hardness of the samples is increased as the temperature of heat treatment increase except the samples a1 and a2. an increase of the heat treatment temperature increases a fraction of martensite [2,3,8], the increase of martensite volume fraction increases the hardenability of steel[3]. but further increase in the mvf was to decrease the hardness; this result is agreed with the results obtained by bello et.al. (2007)[4]. that is why hardness values of samples a1, a2 was less than the values of other samples. martensite enriched in carbon increases the hardenability of steel, when the quenching temperature increase the fraction of martensite increase [2,3,8], but at the lower carbon enrichment. it causes lowering the hardenability of steel (austenite depleted in carbon) and can lead to a transformation of the part of austenite to undesirable bainite [3] . clearly we can see that double quenching raises hardness values (fig.7). this is reported to be attributed to the fine grains of the recrystallized ferrite. they are a result of plastic deformation connected with volume changes accompanying the martensite transformation [3], microstructural refinement is expected to enhance hardness [1, 9]. beside that the increase of martensite volume fraction increases the hardenability of steel. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 391 3. wear test from (fig.8) it has been noticed that wear rate is increased as sliding time increases until it reached highest sliding time. increasing sliding time tends to raise surface temperature which causes cover of oxide on the surface of the sample. during sliding more and more oxide is produced, the metal–metal contact is reduced, thus lowering the wear rate, and leading to transition from severe to mild wear [10, 11]. in (fig.9) when the load is lower than 20 n, wear loss mainly results from plowing and micro-cutting under the action of the abrasive particles and oxides fallen from the sample surface. when the load increases the abrasive particles indents more deeply into the surface; so the repetitive work-hardening in the surface layer will be severer under the repetitive sliding action. eventually cracks propagating and growing induce spalling of the material in the surface layer. the dominant wear mechanism changes are plastic removal and surface fatigue fracture of the deformed layer when the load increases [1]. at the same time, wear rate caused by plowing and micro-cutting is less than that of the original sample under the lower load. as the load increases, the repetitive work-hardening caused by the reciprocated sliding action in the harder layer is smaller. consequently the spalling loss of the treated sample is less than that of the original one too. in the harder surface layer of the treated samples, the depth that the abrasive particles indents is smaller, so that the force needed in the plastic deformation is diminished that the plastic removal in the harder surface layer is smaller, wear volume loss of the treated samples is less than that of the original sample under the higher load [1]. (figs 8 and 9) show that double quenching process enhanced wear properties; this result is agreed with the results obtained by gural et.al. (2007) [5], it is attributed to the higher hardness values are significantly associated with the finer distribution of martensite and ferrite composite microstructure gained from double quenching [4]. microstructural refinement is expected to enhance hardness and then to result in an improvement in the adhesive wear resistance [1,2]. the higher hardness the lower wear rate [12], so the much enhanced wear resistance was of sample b1. (figs 1, 3 and 5) of the microstructure test reveal that the microstructures of the samples of route (1) consist from fine ferrite and martensite phases. coarse martensite was obtained with further increase in volume fraction [4].in the case of specimen a1; further increasing in volume fraction of martensite increases the strength of the dual phase material. unfortunately, increasing the martensite content might reduce ductility and toughness [4]. wear resistance of dual phase steels affect their ductility. if dual phase steels have high ductility, they have high wear resistance as well, generally, dual phase steels having lower mvf have high ductility [2]. therefore, as the samples had lower mvf, it can be expected to have higher ductility and thus high wear resistance [2]. beside that an increasing of the quenching temperature increases the fraction of martensite, but at the lower carbon enrichment. during this process, martensite volume fraction increases while its hardness decreases as mentioned before, which results in a decrease in wear resistance of dual phase steels [2,3]. martensite phase in a microstructure is easily cracked under loads and thus the weight loss from the surface is increased [2] therefore the wear rates of the samples being sever at high load as shown in (fig. 9). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 conclusion 1wear rate for the heat treated samples of low carbon dual phase steel shows improvement in comparison with the original one. 2double quenching showed enhancement in wear properties more than the single quenched samples. 3specimen double quenched from the temperature of 900°c and 850°c showed best wear resistance than the other samples. refrenceses 1. wang z.b., tao n.r., li s., wang w., liu g., lu j., lu k." effect of surface nanocrystallization on friction and wear properties in low carbon steel", journal of materials science and engineering a, vol. 352, pp. 144 -/149, (2003). 2. tekeli s., gural a., ozyurek d.," dry sliding wear behavior of low carbon dual phase powder metallurgy steels" materials and design , vol. 28, issue 5, pp. 1685-1688,( 2007). 3. adamczyk j. , grajcar a." heat treatment and mechanical properties of low-carbon steel with dual-phase microstructure", journal of achievements in materials and manufacturing engineering, vol. 22 ,issue 1, pp. 13-20 ,may (2007). 4. bello k.a. , hassan s.b., abdulwahab m. , shehu u. , umoru l.e. , oyetunji a. , suleiman i.y." effect of ferrite-martensite microstructural evolution on hardness and impact toughness behavior of high martensite dual phase steel" australian journal of basic and applied sciences, 1(4): 407-414, (2007). 5. gural a. ,tekeli s. ,ozyurek d. ,gural m." effect of repeated quenching heat treatment on microstructure and dry sliding wear behavior of low carbon pm steel" journal of materials science forum, vol. 534, pp. 673-676, january, (2007). 6. george e. totten,"steel heat treatment hand book "second edition, taylor and francis group, 2007. 7. asm handbook "mechanical testing and evaluation" vol.8, asm international, 2000. http://www.scientific.net/msf al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 399 الراوي عويد, اسماعيل عبد الرزاق "المعامالت الحرارية للمعادن الحديدية والالحديدية ", قسم هندسة االنتاج .8 . 9191الجامعة التكنلوجية, /والمعادن 9. wang z.b., lu j., lu k." wear and corrosion properties of a low carbon steel processed by means of smat followed by lower temperature chromizing treatment" journal of surface & coatings technology, vol. 201 ,pp 2796 -2801,(2006). 10. gupta v.k., ray s., pandey o.p." dry sliding wear characteristics of 0.13 wt. % carbon steel" materials science-poland, vol. 26, no. 3, pp. 617-631 , (2008). 11. john h. dumbleton , joseph a. donthett, "the unlubricated adhesive wear resistance of metastable austenitic stainless steel containing silicon ", wear, vol.42, pp .305-306,(1977). 12. bressan j.d., daros d.p., sokolowski a., mesquita r.a., barbosa c.a. "influence of hardness on the wear resistance of 174 ph stainless steel evaluated by the pin-on-disc testing" journal of materials processing technology, vol. 205, pp. 353–359, (2008). c si s p mn ni cr elements % 0.097796 0.01275 0.28942 0.06166 1.27698 0.13058 0.16994 mo v cu w ti sn co elements % 0.02835 0.00508 0.14820 0.00738 0.00079 0.02097 0.01732 al pb nb zr ca zn fe elements % 0.00035 0.00894 0.00142 0.0027 0.00002 0.00268 97.7174 table (1) composition of the investigated low-carbon steel. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 martensite volume fraction % sample 36.71 a1 28.9 a2 31.24 b1 25 b2 21.09 c1 15.09 c2 sample heat treatment r o u t 1 (d o u b le q u e n c h e d ) a1 first quenched from temperature 900°c, second quenched from 870°c (booth quenched in water). b1 first quenched from temperature 900°c, second quenched from 850°c (booth quenched in water). c1 first quenched from temperature 900°c, second quenched from 810°c (booth quenched in water). r o u t 2 (s in g le s q u e n c h e d ) a2 quenched from temperature 870°c in water b2 quenched from temperature 850°c in water c2 quenched from temperature 810°c in water d metal as received table (2): heat treatment of steel according to routes 1 and 2. table (3) martensite volume fraction %. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 103 hardness kg/mm 2 sample 168 a1 166 a2 179 b1 173 b2 170 c1 161 c2 159 d table (4) hardness values. fig.1: sample (a1) ferritic – martensitic structure of steel double quenched from the temperature of 900°c and 870°c, (80x) (f: ferrite, m: martensite). m f m f fig.2: sample (a2) ferritic – martensitic structure of steel quenched from the temperature of 870°c, (80x) (f: ferrite, m: martensite). m f fig.3: sample (b1) ferritic – martensitic structure of steel double quenched from the temperature of 900°c and 850°c, (80x) (f: ferrite, m: martensite). m f fig.4: sample (b2) ferritic – martensitic structure of steel quenched from the temperature of 850°c, (80x) (f: ferrite, m: martensite). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 m f fig.5: sample (c1) ferritic – martensitic structure of steel double quenched from the temperature of 900°c and 810°c, (80x) (f: ferrite, m: martensite). fig .7: relationship between quenching temperature and brinell hardness. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 101 fig.(8):relationship between sliding time and wear rate. fig. (9): relationship between applied load and wear rate. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 196 a statitical model for predictin auto-clave expansion of portland cement dr. mahdi s. essa al-saegh asst. prof./department of civil eng. college of engineering/university of babylon abstract: the present study aims aimed to investigate factors affecting the soundness of portland cement (in terms of autoclave expansion test). these factors are c3s, c2s, c3a, c4af, fineness (in terms of specific surface measured by blaine method), the minor oxides mgo, free cao, so3, and the variables obtained from the chemical analysis of cement like silica modulus (sm), alumina ratio (ar), loss on ignition (loi), insoluble residue (ir), and lime saturation factor (lsf). the autoclave expansion prediction models were built by using multiple linear regression analysis and based on (40) different cement samples taken from (7) different iraqi cement factories, indian cement, and kuwaiti cement. (29) of the samples were ordinary portland cement while the other (11) samples were sulphate resisting portland cement. it was found that the multiple linear regression is very suitable for predicting the autoclave expansion of portland cement. it was also found that the increase of fineness of cement, lsf, and loi decreases the autoclave expansion, while the increase in the other factors increases the autoclave expansion. the correlation coefficients of the proposed models were (0.71002 and 0.98338) for the first model, (0.84366 and 0.98789) for the second model, and (0.85593 and 0.98872) for the third model, with and without intercept respectively. key words: soundness of cement, autoclave test, portland cement, expansion, oxides of cement. التمدد في فحص المحمم البخاري للسمنت البورتالندي موديل إحصائي للتنبؤ بمقدار :خالصةال للسمنت )بخاريمعبرَا عنه بطريقة المحمم ال(فحص الثبات ي تؤثر على الدراسة الحالية تهدف إلى تحري العوامل الت بطريقةبالمساحة السطحية النوعية المقاسة معبرًا عنها (النعومة ، (c3s, c2s, c3a, c4af) هي العوامل هذه. البورتالندي (blaine االآاسيد الثانوية ،mgo الجير الحر،free cao ،so3 عليها من التحليل الكيميائي للسمنت لحصوليتم ا، والمتغيرات التي ، ومعامل اإلشباع الجيري (ir) المخلفات غير الذائبة ،(loi)الفقدان أثناء اإليقاد ،(ar)، نسبة االلومينا (sm)مثل معامل السليكا (lsf).من عينات السمنت ) 40 ( علىمستند و الخطي المتعدد باستخدام تحليل االنحدارت بني التمدد بطريقة المحممذج تخمينا إن نم من العينات آانت سمنت بورتالندي ) 29. (سمنت هندي، و سمنت آويتي معامل سمنت عراقية مختلفة،) 7(المختلفة مأخوذة من مين لقد وجد ان االنحدار الخطي المتعدد مالئم جدًا لتخ. آانت سمنت بورتالندي مقاوم للكبريتاتاألخرىعينة ) 11(اعتيادي بينما الـ الفقدان أثناء ، (lsf)ومعامل اإلشباع الجيري آذلك وجد ان الزيادة في نعومة السمنت،. تمدد السمنت البورتالندي بطريقة المحمم معامل االرتباط للنماذج . تقلل التمدد بطريقة المحمم، بينما الزيادة في العوامل االخرى تزيد التمدد بطريقة المحممloi)(اإليقاد ) 0.98872 و 0.85593(للنموذج الثاني، و) 0,98789 و0,84366 (للنموذج االول،) 0,98338 و 0,71002(ن المقترحة آا .ثابت التناسب على الترتيب بوجود وعدم وجود للنموذج الثالث، al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 197 introduction: it is essential that cement paste does not undergo a large change in volume. in particular, there must be no appreciable expansion which, under conditions of restraint, could result in a disruption of the hardened cement paste. such expansion may take place due to the delayed or slow hydration, or other reaction of some compounds present in the hardened cement, namely free lime , magnesia, and calcium sulfate (neville 1995 p.51). the testing of the soundness of cements, so as to ensure that no material showing such a subsequent expansion shall be used, has always therefore been considered of prime importance (lea 1976 p.366). research significance: it is developing a statistical model for predicting the autoclave expansion that comprises most chemical factors and fineness of cement which affect this property. such model help to assess the degree of soundness of cement which a very substantial aspect of durability if the elaborate autoclave test is unavailable. literature review: the autoclave expansion test described by astm c151 is used to detect soundness of neat cement paste. in this test a bar of 25 mm (1 in) square in cross section and with 250 mm (10 in) gauge length, is cured in humid air for 24 hours. the bar is then subjected to accelerated conditions (a steam pressure of about 2±0.07 mpa. (295 psi) and a temperature of 216˚c (240˚f)) for 3 hours. the expansion of the bar due to autoclaving must not exceed 0.8 per cent. the high steam pressure accelerates the hydration of both magnesia and lime (neville 1995 p.53). mgo and free lime are the effective components in cement that can cause delayed expansion. this expansion is due to the formation of ca(oh)2 and mg(oh)2 upon hydration of free cao and mgo respectively. unsoundness due to the presence of free lime may arise from an over-limed mix, inadequate burning, or insufficiently fine grinding and mixing of the raw materials fed to the kiln (lea 1976 p.368). on the other hand, lime added to cement does not produce unsoundness because it hydrates rapidly before the past has set (neville 1995 p.51). the reactivity of mgo depends on rate of cooling of clinker. neville (1995 p.52) stated that only periclase is deleteriously reactive, and mgo present in glass is harmless. up to about 2% of periclase (by mass of cement) combines with the main cement compounds, but excess periclase generally causes expansion and leads to slow disruption. lea (1976 p.369-370) reported that clinkers that are cooled rapidly can carry more magnesia safely than slowly cooled clinkers. cements with as much as 5 per cent magnesia will pass the autoclave test if quickly cooled, and the free lime is low. in slowly cooled clinkers, failure to pass the autoclave test may occur with magnesia content of 3 per cent. the quicker the clinker is cooled the smaller will be the periclase crystallization of the liquid. in addition, mgo content can be made up of magnesia held in solid solution in other clinker compounds or as small crystallization of the clinker liquid. the extent to which the periclase crystals may themselves have impurities in solid solution also appears to influence their speed of hydration. the correlation between autoclave expansion and the (mgo + free cao) content in cement is not strong enough to attribute such expansion entirely to the amount of mgo and free lime in cement. this means that there are other factors that affect autoclave expansion (abdul-latif 2001). the third compound liable to cause expansion is calcium sulfate. this expansion is attributed to the formation of calcium sulphoaluminate. this is harmless when formed in small amounts during the setting of cement, but if large amount of gypsum are present, such that formation of the sulphoaluminate salt continues al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 198 after setting and hardening, expansion occurs. the maximum amount of gypsum that can safely be added is thus related to the ability of the cement to combine with it during the setting, or very early hardening period (lea 1976 p.370). a study by abdul-latif (2001) showed that the autoclave expansion at first decreased as the so3 content increased, while at higher so3 contents there was an increase in expansion. he attributed the reduction in autoclave expansion to the formation of monosulfate phase. when so3 is insufficient to allow c3a and c4af to react completely to form ettringite, the hydration product of these components (i.e. c4ah13) reacts with ettringite under the autoclave test conditions. he suggested that such reaction leads to a decrease, rather than an increase, in solid volume. however, the results obtained by al-jabiri (2002) contradict this interpretation, she stated that an increase in so3 content at low percentage of mgo (originally in cement) does not lead to a significant expansion in the autoclave test for cement paste when either o.p.c. or s.r.p.c. are used. in contrast, there is a tendency for a decrease of expansion with increasing so3 content in cement even at high percentages of so3. she, also, reported that lawrence (1995) in his study on the effect of cement composition on the delayed ettringite formation observed that mgo content has a significant effect on expansion including that due to ettringite formation. he suggested that the expansive hydration of mgo during the elevated temperature hydration or during room temperature water storage may increase the sensitivity of cement to heat curing by acting as an initiator for subsequent ettringite recrystallizion pressure generation and expansion. this interpretation can also be applicable to the results of the autoclave test at high mgo percentages. the c-s-h gel may play a role in the expansion process. the condition of the autoclave test may generate the adsorption of so4-2 ions by c-s-h gel, which causes the decrease or no more expansion in cement pastes, mg(oh)2 may increase the alkalinity of the solution which leads to an expansion in the rate of hydration. more etringite can be formed and more so4-2 can be adsorbed in c-s-h gel that affects its structure and results in poor strength and then high expansion. a further factor that influences the expansion in the autoclave test, though it does not lead to long term expansion in practice, is the content of c3a. lea (1976 p.370) showed that even when the magnesia and free lime are low, the autoclave expansion increases as the calculated content rises about 8 per cent in well crystallized clinker and may exceed the permitted limit at about 14-16 per cent. the iron compound , c4af, has little effect. it is well known that the formation of ettringite as a result of the chemical reaction of gypsum and alumina phase associated with expansion. however, there is still some uncertainty as to precise mechanism. it has been suggested for example, that the solid stage conversion of c3a.13h to c4as.12h is responsible for sulfate expansion, but the evidence points to the presence of 19h, and not 13h hydrate of c3a in set cement. the conversion of 19h hydrate would lead to a decrease, not an increase in solid volume. there is, also, little correlation between the amount of ettringite formed and the degree of expansion observed (lea 1976 p.347-348). from this discussion, it is clear that it is difficult to ascribe expansions directly to increased volume of solid. fineness of cement containing free cao and mgo is the most interesting factor affecting the soundness of cement. as reported by al-jabiri (2002), czenin in 1980 stated that little, but large, free lime particles in hardened paste will cause cracking and spalling, whereas, with increasing fine division of free lime the expansion will become less and more regular. he proved that by taking a neat cement prism with a high content of free lime 13 per cent and finely ground cement. the expansion which occurred was 20 per cent in length but without causing disintegration of the test specimen. the extremely fine distribution of the free lime prevent destruction of the prism. according to lea (1976 p.369), keil (1957) found that a content of 4 per cent periclase crystals below 5µ in size produced only about the same autoclave expansion as 1 per cent of crystals of 30µ-60 µ size. it will be apparent that expansion in the autoclave test is the integrated effect of a number of separated factors. the test gives, therefore, no more a broad indication of the risk of long-term al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 199 expansion in practice, it is not an exact guide and various anomalies are apparent in the available data (neville 1995 p.53 and lea 1976 p.370). abdul-latif (2001) proposed a statistical model for predicting autoclave expansion from mgo content, free lime content, c3a content, and fineness in terms of blaine specific surface. this model was as follows: auto. = 0.06811*free cao% + 0.04394*mgo% 0.0000577*blaine (cm2/gm) + 0.01943*c3a% .….eq.(1) this model is based on 35 observations. the correlation coefficient, standard error, and fvalue are 0.812, 0.1023, and 14.965 respectively. experimental work: in this study, (40) different cement samples were tested, (29) of them were ordinary portland cement while the other (11) samples were sulphate resisting portland cement. table (1) shows the cement sources and the type of their production with the number of samples taken from each factory. tables (2) shows the chemical analysis and physical properties of the cements used in this study. and tables (3) shows the chemical analysis and physical properties limits of the cements used in this study. the autoclave test was used to determine the unsoundness of the cement samples used throughout the present study. the results of this test were obtained from consultant engineering bureau of university of babylon, and it was accomplished according to the iraqi standard specification (iqs no.5 : 1984). model development: the multiple linear regression analysis was used to build the present models. the general purpose of regression analysis is to learn more about the relationship between one or several independent or predictor variables and a dependent or criterion variable. the regression equation or the best-fitting line is determined by minimizing the sum of squares of the residuals between the actual and predicted values of the dependent variables (stat soft 2003). the various elements of the multiple linear regression equation can be illustrated from the general form of the following equation: y = a0 + a1x1 + a2x2 +….+anxn where: y: the predicted value of the dependent variable. x1, x2,…, xn: the independent variables (predictors). a0: the intercept coefficient (constant). a1, a2,…, an: the partial regression coefficients of the independent variables. n: the number of independent variables included in regression equation. the statistical analysis was done with the aid of computer software statistica version 6-2001. three methods of regression were applied. they are: 1. backward elimination. 2. forward regression. 3. standard method or all variables regression. to evaluate the proposed models, the following statistical factors are used: al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 200 multiple r: the coefficient of multiple correlation is the positive square root of r-square (the coefficient of multiple determination). this statistical factor is useful in multivariate regression (i.e. multiple independent variables) when it is wanted to describe the relationship between the variables. r-square: this coefficient of multiple determination measures the reduction in the total variation of the dependent variable due to the (multiple) independent variables. r2 = 1 [residual ss/total ss] where: residual ss: is the error sums of square. total ss: is the total sums of square. the r-square value is an indicator of how well the model fits the data, r-square close to 1.0 indicates that it has accounted for almost all of the variability with the variables specified in the model. adjusted r-square: the r-square is adjusted by dividing the error sum of squares and total sums of square by their respective degrees of freedom. adjusted r2 = 1 [(residual ss/dfr)/(total ss/dft)] std. error of estimate: this statistic coefficient measures the dispersion of the observed values about the regression line. f-value: the f-value is used as a test of the relationship between the dependent variable and the set of independent variables. f = regression mean square/residual mean square. the range of difference (df) between the actual and predicted autoclave expansion values was calculated for each model within confidence interval of 0.95. this means that there is a probability of 95% of difference between the actual and the predicted values falls within a range of ±df, thus, the actual values equals to predicted values ± df independent variables: the following variables are selected to be as the independent variables: 1. the four main compounds of portland cement (i.e. c3s, c2s, c3a, and c4af) which were calculated using bogue`s equations. 2. the fineness of cement (in terms of blaine specific surface). 3. chemical analysis parameters (i.e. mgo, free cao, so3, loi, ir, and lsf). 4. silica modulus and alumina ratio. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 201 the proposed models: the following statistical models are obtained: 1. model (1): in this model, backward stepwise method was applied. the final form of this model is as follows: with intercept: auto. exp. = 0.09929 + 0.076702*mgo% ….eq.(2) r = 0.71002 r2 = 0.50412 adjusted r2 = 0.49107 s.e.= 0.064467 fvalue = 38.63166 without intercept: auto. exp. = 0.061130*mgo% + 0.061591*so3% ….eq.(3) r = 0.98338 r2 = 0.96704 adjusted r2 = 0.96530 s.e.= 0.06201 fvalue = 557.4398 2. model (2): forward stepwise method was used in developing this model. the final form of this model is as follows: with intercept: auto. exp. = 2.91305 + 0.06627*mgo% + 0.07888*ir% + 0.113195*so3% 2.96120*lsf% -0.02958*loi% 0.10252*sm 0.00925*c2s% ..…eq.(4) r = 0.84366 r2 = 0.71176 adjusted r2 = 0.64871 s.e.= 0.05356 fvalue = 11.28843 without intercept: auto. exp. = 0.05756*mgo% + 0.06185*ir% + 0.15899*so3% 1.38250*lsf% -0.01368*loi% + 0.01482*c3s% + 0.09823*ar + 0.00700*c2s% ..…eq.(5) r = 0.98789 r2 = 0.97594 adjusted r2 = 0.96993 s.e.= 0.05774 fvalue = 162.2572 3. model (3): standard method in which all possible factors are included in this model: with intercept: auto. exp. = 3.07983 + 0.05393*mgo% + 0.12288*so3% 0.01306*freecao% 0.03444*loi% + 0.07678*ir% 3.28013*lsf% 0.13571*sm + 0.00301* ar + 0.00757*c3s% 0.00472* c2s% 0.00272*c3a% 0.01667* c4af% 0.00013*blaine(m2/kg) ….eq.(6) r = 0.85593 r2 = 0.73261 adjusted r2 = 0.59892 s.e.= 0.05723 fvalue = 5.47972 without intercept: auto. exp. = 0.06236*mgo% + 0.15717*so3% + 0.04806*free cao% 0.01037*loi% + 0.04256*ir% 1.84275*lsf% + 0.10076*sm + 0.07660* ar + 0.01478*c3s% + 0.00510* c2s%+ 0.01761*c3a% + 0.01648* c4af% 0.00038*blaine(m2/kg) ….eq.(7) r = 0.98872 r2 = 0.97756 adjusted r2 = 0.96675 s.e.= 0.06071 fvalue = 90.4699 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 202 comparison between models with and without intercept: as mentioned earlier, two models were developed for each method of regression (i.e. backward stepwise (model (1)), forward stepwise(model (2)), and standard method or all variables in model (model (3))) using the same data and the same independent variables, to prove that regression through the origin is more suitable for the data. the first model passes through the origin and the other had an intercept (a0) of 0.09929, 2.91305, and 3.07983 for the three method of regression respectively. table (4) shows r, r2, adjusted r2, fvalue, s.e., and df for the models with and without intercept. it is obvious that r, r2, adjusted r2, fvalue, s.e., and df for models with intercept are less than that of models without intercept. it is decided that the models which pass through the origin (without intercept) are more suitable and recommended. models examination: model examination was done for the models which pass through the origin (without intercept), which were found to be more suitable. the distribution of residuals is shown in figure (1). from this figure it is clear that the residuals are almost normally distributed. it is also clear that the residuals gathered around zero. this indicates that there are no evidences that the models are inadequate, or there is an error in analysis. in figure (2) the observed values of the autoclave expansion test are plotted against the predicted values. it is clear that the points roughly follow a straight line. this indicates that the models are appropriate for the data, and they are correctly specified. to check the validity of the proposed models to predict the autoclave expansion of cement, two samples of portland cement were tested. one of them is sulphate resisting portland cement while the other is ordinary portland cement. the details of these cements are given in table (5). table (6) gives the observed and predicted values of the autoclave expansion. from this table it is clear that the maximum difference between the observed and predicted values is about +0.07. thus, it may be concluded that the present model is appropriate to predict the autoclave expansion with a good accuracy. discussion: as mentioned earlier, the models which pass through the origin (without intercept) are more suitable and recommended. from these models the following points have been recorded: 1. it is obvious that the correlation coefficients, fvalue, and the standard error of the three models are very close. 2. as explained earlier, fineness of cement is the most interesting factor affecting the soundness of cement. from the third model, it is clear that the autoclave expansion decreases with the increase in cement fineness. this result is in agreement with the results obtained by (czenin 1980). 3. from the three models, it can be deduced that the increase in mgo and so3 contents increase the autoclave expansion. the free cao has the same effect but at a lesser degree. this result seems acceptable as they play a role in cement paste volume change as mentioned earlier. 4. as expected c3a and c4af increase the autoclave expansion, this is obvious from the correlation coefficient in third model. this may be attributed to the fact that these two compounds cause expansion of cement paste as discussed earlier. this is online with what was demonstrated by lea (1976 p.370). al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 203 5. on the basis of the present models, it is proven statistically that the autoclave expansion increases when the contents of c3s and c2s are increased. this behavior may be explained in the light of the fact that the hydration of silicates is associated with a volume increase. 6. depending on the present models, the autoclave expansion increases with the increase in ir (insoluble residual) content. ir is defined the amount of amorphuse silica present in the clay minerals of the raw materials used in cement manufacture (since this silica is not soluble in hydrochloric acid unlike most of cement constituents). in addition, ir gives an indication on the efficiency of the burning process. on the basis of this discussion the effect of ir seems reasonable. 7. it is clear that loi negatively affects the autoclave expansion. this behavior seems acceptable as loi refers to the extent of carbonation and hydration of free magnesia due to the exposure of cement to the atmosphere (neville 1995 p.11). 8. the appearance of ar and sm as positive factors to autoclave expansion in the present models may be explained as alumina and iron oxides are the main fluxes in cement burning process. when the content of them are low the amount of liquid formed at clinkering temperature becomes insufficient to permit sufficiently rapid combination of the remaining cao (lea 1976 p.135). 9. lime saturation factor lsf appears as a negative factor in the second and the third models. this seems reasonable as lime saturation factor represents the factors obtained by equation (8). the increase in (al2o3 and fe2o3) results in a decrease in lsf and subsequently in an increase in the autoclave expansion. ( ) )8.....( 0.65fe2o3) 1.2al2o3 (2.8sio2 0.7so3 cao lsf ++ − = conclusion: 1. the multiple linear regression is found to be very suitable for predicting the autoclave expansion of portland cement. 2. it is found that the models which pass through the origin (without intercept) are more suitable and recommended. 3. the increase in mgo and so3 contents increases the autoclave expansion. the free cao has the same effect but at a lesser degree. 4. the increase in fineness of cement, lsf, and loi decreases the autoclave expansion, while the increase in the other factors increases the autoclave expansion. 5. the correlation coefficients of the proposed models were (0.71002 and 0.98338) for the first model, (0.84366 and 0.98789) for the second model, and (0.85593 and 0.98872) for the third model, with and without intercept respectively. references: abdul-latif, a.m., 2001 “optimum gypsum content in concrete and cement mortar”, ph.d. thesis, university of baghdad. college of engineering. al-jabiri, t.m., 2002 “concrete strength development related to mgo and so3 contents in cement”, m.sc thesis, university of baghdad. college of engineering. astm c151-84 “standard test method for autoclave expansion of portland cement” al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 204 annual book of astm standards 1989, section 4, volume 04.01, pp. 120-122. astm c204-84 “standard test method for fineness of portland cement by air permeability apparatus” annual book of astm standards 1989, section 4, volume 04.01. czernin, w., 1980 “cement chemistry and physics of civil engineering” english edition, george godwin ltd., london, 196 pp. (cited by al-jabiri 2002). iraqi organization of standards iqs no.5, 1984 “iraqi standard specification for portland cements, icosqc”, baghdad, iraq. keil, f., (1957) revue mater, constr. trav. publ. 503/504,262. (cited by lea 1976). lawrence, c.d., 1995 “mortar expansions due to delayed ettringite formation: efect of curing period and tempreature”, ccr, vol.25, no.4, pp.903-914. (cited by al jabiri 2002). lea, f.m., 1976 “the chemistry of cement and concrete”, 3rd edition, edward arnold, london 727 pp. neville, a.m., 1995 “properties of concrete”, 4th and final edition, pitman publishing, london. 844 pp. stat soft 2003, “multiple regreesion”, electronic text book. http://www.statsoft.com/textbook/stnonlin.html#general table (1): sources of the cement samples used in the analysis no. factory type of cement no. of samples 1 al-najaf alashraf cement plant o.p.c. 5 2 new cement plant of kufa o.p.c. 5 3 alsada cement plant o.p.c. 7 4 south cement plant o.p.c. 6 5 um-qaser grinding station o.p.c. 4 6 lion cement -india o.p.c. 2 7 al-muthana cement plant s.r.p.c. 5 8 kerbala cement plant s.r.p.c. 5 9 kuwait cement plant s.r.p.c. 1 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 205 auto. exp. .4 0 .3 6 .4 5 .3 4 .4 3 .4 9 .4 2 .4 4 .2 3 .3 3 .3 2 .3 3 .3 7 .4 0 .2 2 .2 4 .4 0 .3 3 .3 0 .3 4 blaine (m2/kg) 31 4. 4 28 8. 0 30 2. 7 29 6. 6 29 8. 1 32 3. 0 31 4. 8 30 6. 1 29 0. 9 32 7. 3 38 6. 2 32 8. 4 34 9. 6 33 9. 6 39 8. 4 29 1. 5 39 1. 0 29 7. 0 28 4. 7 30 5. 7 fst (min) 2 25 24 0 22 5 20 0 21 5 24 5 26 5 23 5 21 0 23 0 19 0 24 5 23 0 22 0 17 0 19 0 15 5 23 0 26 0 23 0 ph ys ic al p ro pe rti es ist (min) 1 25 14 0 14 5 11 0 12 5 14 5 17 0 16 0 12 0 16 0 10 0 14 0 12 0 12 0 10 0 10 0 95 10 0 15 0 14 0 l.s.f.% 0. 85 0. 90 0. 86 0. 87 0. 88 0. 93 0. 88 0. 85 0. 9 0. 9 0. 89 0. 86 0. 86 0. 85 0. 89 0. 87 0. 86 0. 89 0. 89 0. 88 ir% 0. 53 0. 92 1. 04 0. 73 1. 30 0. 78 0. 81 1. 35 0. 58 0. 65 1. 22 1. 40 1. 15 1. 30 0. 55 0. 63 0. 80 1. 15 1. 40 0. 86 l.o.i.% 1. 57 1. 23 1. 32 1. 13 1. 35 1. 61 1. 55 1. 61 0. 92 .9 4 3. 30 3. 53 2. 61 1. 93 1. 24 1. 19 2. 22 1. 77 2. 31 1. 39 free lime% 1. 27 1. 29 1. 40 0. 95 1. 17 1. 19 1. 35 1. 60 0. 88 1. 17 1. 34 1. 29 1. 46 1. 77 1. 42 0. 9 2. 02 1. 22 1. 23 1. 40 so3% 2. 43 2. 48 2. 41 2. 32 2. 60 2. 47 2. 63 2. 57 2. 75 2. 33 2. 77 2. 40 2. 40 2. 61 2. 54 2. 44 2. 61 2. 38 2. 18 2. 39 mgo% 3. 35 2. 55 3. 55 3. 82 3. 51 3. 87 2. 93 3. 11 4. 43 4. 41 3. 28 2. 71 3. 15 3. 45 3. 20 4. 19 3. 41 2. 73 2. 56 2. 37 fe2o3% 3. 20 3. 80 3. 80 3. 96 3. 76 3. 44 3. 30 3. 28 3. 24 3. 20 3. 08 3. 60 3. 60 3. 00 3. 08 3. 24 3. 80 4. 32 4. 16 4. 68 al2o3% 5. 44 5. 08 4. 66 4. 62 4. 72 4. 94 6. 06 5. 94 5. 82 5. 98 4. 44 4. 76 4. 76 5. 30 6. 14 5. 38 4. 48 4. 30 4. 28 3. 58 sio2% 21 .6 5 21 .2 0 21 .5 0 21 .6 6 21 .2 0 20 .1 0 20 .6 4 20 .9 4 20 .0 6 20 .6 8 20 .8 4 21 .1 8 21 .3 8 21 .6 4 21 .0 6 21 .3 8 21 .1 2 21 .1 4 21 .2 4 21 .7 2 ch em ic al a na ly si s cao% 61 .8 63 .0 3 62 .2 3 61 .5 62 .2 3 62 .7 8 62 .6 4 62 .2 3 62 .0 6 61 .8 7 61 .4 3 61 .1 0 61 .3 8 61 .6 9 63 .3 5 61 .2 3 61 .6 9 62 .7 8 62 .9 1 63 .3 2 ty pe o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . fa ct or y al -n aj af al -a sh ra f al -n aj af al -a sh ra f al -n aj af al -a sh ra f al -n aj af al -a sh ra f al -n aj af al -a sh ra f ne w ku fa ne w ku fa ne w ku fa ne w ku fa ne w ku fa al -s ad a al -s ad a al -s ad a al -s ad a al -s ad a al -s ad a al -s ad a so ut h so ut h so ut h no . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 206 auto. exp. .3 3 .3 2 .2 8 .4 3 .3 9 .3 1 .4 0 .2 3 .2 4 .2 3 .2 4 .2 2 .2 3 .2 2 .2 3 .2 3 .2 2 .2 2 .2 4 .3 0 blaine (m2/kg) 30 0. 2 29 0. 9 29 2. 5 34 1. 8 34 7. 0 30 5. 7 34 2. 2 28 1. 6 29 3. 8 28 1. 6 26 5. 0 30 3. 0 29 1. 0 30 9. 0 29 0. 0 28 1. 0 30 0. 4 31 6. 3 28 4. 7 28 4. 0 fst (min) 2 10 21 0 24 0 24 0 23 5 23 5 20 5 22 5 25 0 22 5 28 0 26 0 23 0 21 5 27 0 27 5 24 0 18 0 22 5 26 0 ph ys ic al p ro pe rti es ist (min) 1 20 11 0 12 5 13 5 14 5 15 0 10 5 14 5 15 0 14 5 17 5 14 5 17 0 13 5 16 5 15 0 13 0 80 14 0 14 5 l.s.f.% 0. 88 0. 89 0. 87 0. 87 0. 87 0. 89 0. 90 0. 88 0. 90 0. 88 0. 89 0. 88 0. 90 0. 86 0. 88 0. 90 0. 88 0. 88 0. 90 0. 87 ir% 0. 92 0. 51 0. 32 0. 95 0. 83 1. 00 1. 09 0. 79 0. 90 0. 79 0. 73 1. 35 1. 05 1. 30 0. 92 1. 30 1. 17 0. 54 0. 42 0. 70 l.o.i.% 1. 62 1. 30 1. 04 3. 00 2. 55 3. 56 1. 98 1. 90 2. 50 1. 90 2. 10 2. 33 1. 41 2. 50 1. 80 1. 21 1. 16 0. 81 1. 23 1. 20 free lime% 1. 04 0. 95 0. 78 1. 40 1. 23 1. 20 1. 68 1. 35 1. 10 1. 35 1. 29 1. 35 1. 47 0. 61 1. 51 1. 52 1. 57 0. 81 1. 23 1. 20 so3% 2. 23 2. 67 2. 73 2. 75 2. 23 2. 66 2. 21 2. 49 2. 41 2. 49 1. 89 2. 03 1. 85 2. 03 1. 92 2. 15 1. 90 2. 05 1. 90 2. 16 mgo% 2. 66 3. 75 2. 76 3. 85 3. 31 3. 55 4. 28 1. 85 1. 90 1. 85 2. 00 1. 95 2. 14 3. 20 1. 40 1. 87 1. 71 2. 00 1. 72 1. 40 fe2o3% 4. 80 3. 72 4. 39 3. 32 3. 40 3. 60 3. 60 4. 16 4. 20 4. 16 5. 40 5. 80 5. 68 3. 16 5. 20 5. 90 5. 32 5. 60 5. 44 5. 50 al2o3% 4. 50 4. 88 4. 52 5. 10 5. 78 4. 20 4. 84 5. 34 5. 55 5. 34 3. 55 3. 72 3. 06 4. 36 3. 94 3. 04 3. 68 3. 22 3. 58 3. 60 sio2% 21 .2 8 21 .0 21 .8 20 .5 2 20 .8 0 20 .9 6 20 .4 2 21 .0 0 20 .3 0 21 .0 0 21 .5 3 21 .2 0 21 .6 0 22 .0 0 21 .6 0 21 .4 2 21 .7 2 21 .9 0 21 .5 6 22 .1 0 ch em ic al a na ly si s cao% 62 .5 9 61 .9 6 62 .4 5 60 .7 9 61 .3 8 61 .1 0 62 .2 3 62 .7 1 62 .5 0 62 .7 1 62 .9 8 62 .5 0 64 .0 3 61 .1 8 63 .4 7 63 .7 5 63 .7 5 62 .4 2 64 .4 0 63 .5 0 ty pe o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. s. r. p. c. fa ct o ry so ut h so ut h so ut h um -q as er um -q as er um -q as er um -q as er li on c em en t -in di a li on c em en t -in di a al -m ut ha na al -m ut ha na al -m ut ha na al -m ut ha na al -m ut ha na ke rb al a ke rb al a ke rb al a ke rb al a ke rb al a ku wa it ce m en t p la nt no . 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 207 auto. exp. .3 4.4 5 .2 3.4 9 .2 2.4 .2 8. 34 .3 1.4 3 .2 3.2 4 .2 2.2 4 .2 2.2 4 .3 0 blaine (m2/kg) 28 831 4. 4 29 0. 932 7. 3 29 1. 539 8. 4 28 4. 730 5. 7 30 5. 734 7. 0 28 1. 629 3. 8 26 5. 030 9. 0 28 1. 031 6. 3 28 4. 0 fst (min) 20 024 0 21 023 0 15 524 5 21 026 0 20 524 0 22 525 0 21 528 0 18 027 5 26 0 ph ys ic al p ro pe rti es ist (min) 11 014 5 12 017 0 95 14 0 10 015 0 10 515 0 14 515 0 13 517 5 80 16 5 14 5 l.s.f.% 0. 85 0. 90 0. 85 0. 93 0. 86 0. 89 0. 87 0. 89 0. 87 0. 90 0. 88 0. 90 0. 86 0. 90 0. 88 0. 90 0. 87 ir% 0. 53 1. 30 0. 58 0. 81 0. 55 1. 40 0. 32 1. 40 0. 83 1. 09 0. 79 0. 90 0. 73 1. 35 0. 42 1. 30 0. 70 l.o.i.% 1. 13 1. 57 0. 92 1. 61 1. 19 3. 53 1. 04 2. 31 1. 98 3. 56 1. 90 2. 50 1. 41 2. 50 0. 81 1. 80 1. 20 free lime% 0. 95 1. 29 0. 88 1. 60 0. 92. 02 0. 78 1. 4 1. 20 1. 68 1. 10 1. 35 0. 61 1. 47 0. 81 1. 57 1. 20 so3% 2. 32 2. 60 2. 33 2. 75 2. 42. 77 2. 18 2. 73 2. 21 2. 75 2. 41 2. 49 1. 85 2. 49 1. 92. 15 2. 16 mgo% 2. 55 3. 82 2. 93 4. 41 2. 71 4. 19 2. 37 3. 75 3. 31 4. 28 1. 85 1. 90 1. 85 3. 20 1. 40 2. 00 1. 40 fe2o3% 3. 20 3. 96 3. 23. 44 3. 03. 80 3. 27 4. 80 3. 40 3. 60 4. 16 4. 20 3. 16 5. 80 5. 20 5. 90 5. 50 al2o3% 4. 62 5. 44 4. 94 6. 06 4. 44 5. 38 3. 58 4. 88 4. 20 5. 78 5. 34 5. 55 3. 06 5. 34 3. 04 3. 94 3. 60 sio2% 21 .6 621 .2 0 20 .0 620 .9 4 20 .8 421 .6 4 21 .0 21 .8 20 .4 220 .9 6 21 .0 20 .3 21 .0 22 .0 21 .4 221 .9 22 .1 0 ch em ic al a na ly si s cao% 61 .0 563 .0 3 61 .8 762 .7 8 61 .1 063 .3 5 61 .9 663 .3 2 60 .7 962 .2 3 62 .5 062 .7 1 61 .1 864 .0 3 62 .4 263 .7 5 63 .5 0 ty pe o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . o .p .c . s. r. p. c s. r. p. c s. r. p. c fa ct o ry al -n aj af al -a sh ra f ne w ku fa al -s ad a so ut h um -q as er li on ce m en t in di a al m ut ha na ke rb al a ku wa it ce m en t pl an t no . 1 2 3 4 5 6 7 8 9 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 208 table (4): r, r2, adjusted r2, fvalue, and s.e. for the models with and without intercept. model r r2 adjusted r2 fvalue s.e. df with intercept 0.71002 0.50412 0.49107 38.63166 0.06446 ±0.080 1 without intercept 0.98338 0.96704 0.96530 557.4398 0.06201 ±0.075 with intercept 0.84366 0.71176 0.64871 11.28843 0.05356 ±0.073 2 without intercept 0.98789 0.97594 0.96993 162.2572 0.05774 ±0.068 with intercept 0.85593 0.73261 0.59892 5.47972 0.05723 ±0.072 3 without intercept 0.98872 0.97756 0.96675 90.4699 0.06071 ±0.070 table (5) property of cement used for checking the proposed models. chemical analysis physical properties no. factory type cao% sio 2 % al2 o 3 % fe 2 o 3 % m go % so 3 % free lim e% l.o .i% ir% l.s.f.% blaine (m 2/kg) auto. exp. 1 al-sada o.p.c. 61.48 20.96 5.92 3.0 3.55 2.41 1.23 2.17 1.18 0.86 348.5 0.36 2 kerbala s.r.p.c. 64.5 2.2 3.67 5.54 1.5 2.06 1.68 0.5 1.13 0.91 320 0.25 table (6) observed and predicted autoclave expansion. predicted auto. exp. model(1) model(2) model(3) no. factory observed auto. exp. with intercept w ithout intercept w ith intercept w ithout intercept w ith intercept w ith intercept 1 al-sada 0.36 0.371 0.365 0.351 0.390 0.32 0.38 2 kerbala 0.25 0.214 0.218 0.181 0.20 0.180 1.181 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 209 -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 residual values of the autoclave expansion obtained by the first model. (a) 0 2 4 6 8 10 12 14 16 18 n o of o bs er va ti on s -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 residual values of the autoclave expansion obtained by the second model. (b) 0 2 4 6 8 10 12 14 16 18 20 n o. o f o bs er va ti on s -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 residual values of the autocalve expansion obtained by the third model. (c) 0 2 4 6 8 10 12 14 16 18 20 n o. o f o bs er va ti on s fig. (1) the residuals distribution of the autoclave expansion obtained by the present models. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 210 0.18 0.20 0.22 0.24 0.26 0.28 0.30 0.32 0.34 0.36 0.38 0.40 0.42 0.44 0.46 predicted values of autoclave expansion by the first model (a) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 o bs er ve d v al ue s of a ut oc la ve e xp an si on t es t r es ul ts 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 predicted values of autoclave expansion by the second model (b) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 o bs er ve d v al ue s of a ut oc la ve e xp an si on t es t r es ul ts 0. 14 0. 16 0. 18 0. 20 0. 22 0. 24 0. 26 0. 28 0. 30 0. 32 0. 34 0. 36 0. 38 0. 40 0. 42 0. 44 0. 46 predicted values of autoclave expansion by the third model (c) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 o bs er ve d v al ue s of a ut oc la ve e xp an si on t es t r es ul ts fig. (2) the predicted values of the autoclave expansion against the predicted values obtained by the present models. 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 572 تأثير مخمفات محطة كيرباء المسيب الحرارية عمى بعض الخواص الفيزيائية والكيميائية لمياه نير الفرات جبار عمي لفتو امير ىاشم حسين قيس حاتم محمد المعيد التقني/المسيب المعيد التقني/المسيب جامعة بابل -كمية اليندسة 4102تشرين االول 02 ُقبل 4102 اذار 10ُاستمم الخالصة يتضمن البحث دراسة تحميمية لعينات من نير الفرات قبل وبعد محطة كيرباء المسيب الحرارية. استخدمت ني، الكدرة، العسرة، الكمورايد، القاعدية، المواد طرق قياسية لتقدير كل من التوصيل الكيربائي، األس الييدروجي الصمبة العالقة والمواد الصمبة الكمية. حيث أخذت عينة واحدة في اليوم األول من كل شير مثمت القيم 9002أجريت الدراسة لسنة واحدة وىي سنة .م0000 م،000م، 900م، 00وعمى ابعاد قبل وبعد منطقة الطرح لمنيرالشيرية. أخذت العينات وتبين حدوث تغير أظيرت الدراسة تأثر بعض الخواص التي تم قياسيا بمياه المخمفات التي تطرحيا المحطة. في جميع الخواص وتميل ىده الخواص الى العودة الى قيميا قبل المحطة كمما ابتعد النير عن موقع الطرح. مبات مياه الري )خاصيتي التوصيل الكيربائي وتنطوي الدراسة عمى مقارنة بعض الخواص التي تم قياسيا بمتط .وكمية المواد الصمبة الكمية( كممات رئيسية التموث, تموث االنيار, المموثات, مموثات مياه االنيار, المخمفات الصناعية, المخمفات الصناعية المموثة لالنيار 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 572 the effect musayyib thermal power station waste water on some physical and chemical properties of the euphrates river water qais hatem ameer hashim jabbar ali college of engineering technical institute technical institute babylon university musaieb musaieb abstract this research deals with analyzing for samples from euphrates river before and after the power plant of mussaibe. standard methods are used to find electric conductivity, ph, turbidity, hardness, chloride, alkality, total suspended solid and total solid. the study takes twelve months during 2009, such that one sample was taken in the first day of the month represents the monthly value. the samples were taken from euphrates river before the plant and after the the plant by 50m, 200m, 500m and 1000m from outflow of the plant. the study shows the effect of the plant on the properties that taken in the study. the study contains also effect the plant on the irrigation water properties (electric conductivity, total solid) key words: pollution, pollution of the rivers, pollutants, contaminants of the rivers, industrial waste, contaminants of the rivers. المقدمة لطبيعية عمى االطالق حيث تعتبر عامال اساسيا ترتكز عميو حياة االنسان وكافة تعتبر المياه من اىم الموارد ا انشطتو االجتماعية في مختمف المجاالت. وتتميز المياه عن غيرىا من الموارد الطبيعية بكون كميتو ثابتة في ادر المياه تدىورا الكرة االرضية ويتجدد خالل فترة معينة من الزمن بفعل الدورة الييدرولوجية، وقد شيدت مص كبيرا في اآلونة االخيرة لعدم توجيو قدر وافر من االىتمام بيا، فقد تميزت السنوات العشرون االخيرة بتدىور كبير في البيئة الطبيعية العراقية، ابتداء من تموث اليواء وانتياء بتموث التربة والمياه. حيث يمر العراق بمرحمة مياه وذلك نتيجة لتعدد مصادر التموث فيو مع عدم وجود استراتيجيات لتطوير انحدار وتردي متعمق بنوعية ال وتعزيز االسس لتوفير مياه نظيفة. فقد تموثت مياه العراق ابتداء من تموث مياه الشرب واالنيار وانتياء بالمياه مشكمة تموث المياه السطحية والجوفية. ونتيجة ألىمية موضوع تموث المياه فقد دعى الباحث الى التركيز عمى مع تحديد عناصر ومصادر التموث مع التركيز نوع من انواع التموث في العراق وىو التموث الناتج من االستخدامات الصناعية ) تموث الناتج من محطات توليد الطاقة (. الدراسات السابقة المخمفات عمى مياه االنيار. مشكمة المخمفات الصناعية وغيرىا من تسات التي تتناولتوجد العديد من الدرا واحد فقط عمى النير ومنيا عنصر نيا ما اشتمل دراسة تأثيروبصورة عامة تنقسم ىذه الدراسات الى نوعين: م الدراسات.فيما يمي عدد يسير من ىذه و عمى النير، عنصر واحداكثر من تأثير دراسة تناول ما 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 577 محطة معالجة كوبرزعمى نير سسكوييانا. تستمم ىذه درس بوير تأثير مياه الصرف الصحي المطروحة من المحطة مياه الصرف الصحي من مستشفى الباست ومدينة كوبرز. تمت الدراسة من خالل اخذ عينات من تسع مواقع منتخبة تقع عمى مجرى النير وقياس درجة الحرارة، األوكسجين المذاب، ودرجة الحموضة، ترات والنيتروجين الكمي، والفوسفور ومستويات البكتريا القولونية البرازية. ويتم والتوصيل الكيربائي، النتريت والن . قام [bauer:2010]اجراء ىذه الدراسة بصورة دورية لضمان بقاء المموثات ضمن المستويات المحددة لمنير نداسكي، حيث فورتنر باعداد دراسة حول تأثير المخمفات المطروحة من مدينة بوسيروس اوىايو عمى نير سا انتخب الباحث اربع محطات الخذ العينات من النير امام موقع المدينة واربع اخر تقع خمف المدينة، وكان العناصر التي تم دراستيا ىي الصوديوم، البوتاسيوم، المغنيسيوم، الكاليسيوم، الستروديوم، االلمنيوم، المنغنيز، . أعد كاريكاري دراسة حول [fortner: 2003]لمدينة عمى النير الموليبدينوم. اظيرت الدراسة انخفاض تأثير ا تقييم نوعية مياه نير دينزو في غانا، تناولت الدراسة عددا من المؤثرات الفيزيائية والكيميائية وىي الرقم الييدروجيني، العسرة، العكورة، الصوديوم، الكالسيوم، المنغنيسيوم، البوتاسيوم، والكاربونات، والكمور، – 20.9والعسرة 7..2 -2.9والكبريتات. ومن ضمن النتائج التي توصل الييا تراوح الرقم الييدروجيني لمنير . في دراسة لسميث قام خالليا بقياس الرقم الييدروجيني لمياه االمطار [karikari: 2004]لتر \ممغم 000 وتكساس في امريكا خالل االعوام من المتجمعة في البرك لممناطق الزراعية في شيكاشا وايل رينو وريسل . وكان المعدل السنوي لمرقم الييروجيني لمياه االمطار المتجمعة في البرك اكبر من ذلك 0222-0271 0.1باوطأ قيمة شيرية ىي 2.0 – 0.2، حيث كانت تمك القيم بين 0.5المعدل لمياه االمطار النقية [smith: 1984]المواد الذائبة والعالقة في نير اورينوكو، وكان من ابزر النتائج . قدم ويميام دراسة حول تركيز لتر من ماء النير والتي تعادل كمية مواد عالقة \ممغم70التي توصل الييا ان كمية المواد العالقة الكمية ىي ئبة % من ىذه الكمية، وكانت كمية المواد الذا25سنة تشكل المواد الغير عضوية \طن005*20سنوية مقدارىا . وفي [william: 1989]لتر من ماء النير \ممغم90لتر وكمية المواد الذائبة الغير عضوية \ممغم.1الكمية دراسة اليرفن عمى نير بوفالو في مدينة نيويورك من خالليا قدم العالقة بين العكورة، المواد الصمبة العالقة احث ارتفاع التموث نتيجة التراكيز العالية لمبكتيريا لمحد وبكتيريا القولون، ومن ابرز النتائج التي توصل الييا الب . قام ىويك باعداد [irvinne: 2002]الذي ادى الى التوصية ببناء محطة لتحسين نوعية المياه في ذلك النــير دراسة حول العكورة في بحيرة كارل بالكويل واوكالىوما، كان من ضمن النتائج التي توصل الييا ىو انخفاض . [howick: 1985]العكورة لمياه سطح البحيرة خالل فصل الشتاء وارتفاع ىذه القيم خالل فصل الصيف قيم عمى طول الجزء الشمالي الغربي من (s)والمموحة (ta)أعد كاي دراسة حول العالقة بين القموية الكمية من العالقات المتحكمة التي المحيط االطمسي من بحر البررادور الى المناطق المدارية. وتوصل الى نوعين تربط بين ىذين المتغيرين: االولى العالقة التي تحكم المتغيرات فى االنيار والثانية العالقة التي تحكم المتغيرات . قام ليو بدراسة الرسوبيات التي يقذفيا نير اليانغتسي في بحر الصين، [cai: 2010]عمى طول الشواطئ كم، ووجد ان معظم الرسوبيات تتكون 700كم وطول 000متر وعرض 0.فاع والتي تتشكل بييئة رفوف بارت 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 572 ( ممم. ووجد ان التركيب الكيميائي ليذه الرسوبيات يتكون 0.7-0.5من حبيبات الطين والغرين باحجام حبيبية ) % 1% ومن السيمكتايت بنسبة 2% ومن الكالونايت بنسبة 09% ومن الكمورايد بنسبة 20من االيالت بنسبة [liu:2006] تناول كامبيل في دراسة لو طريقة الحتساب عسرة الماء من خالل ايجاد تركيز المغنيسيوم . .[campbell:2010]والكالسيوم، وكانت الدراسة تضم عينات من ماء النير والحنفية وماء الشرب محطات الطاقة الحرارية تبنى عادة بالقرب من مصدر مائي رئيس ودائم لتوفير تستخدم المحطات الحرارية لتوليد الطاقة الكيربائية، و :(canada:2004)باالتيالماء الالزم الستمرار عمل المحطة. ويتمخص مبدأ عمل المحطة تكوين بخار الماء المضغوط في المرجل: وذلك عن طريق دخول الماء الخالي من االمالح األتي من -0 الفحم او مشتقات البترول يقوم المرجل بانتاج البخار المضغوط. محطة التناضح العكسي وباستخدام الوقود مثل بين: حيث يعتبر التوربين محرك المحطة الحرارية ونتيجة لتسميط ر يتجو البخار المضغوط بعد ذلك الى التو -9 ضغط البخار عميو يبدأ بالدوران. ذلك تتولد الطاقة الكيربائية التي تنقل عبر بين يدور المولد، وبر ان التوبين مرتبط بالمولد ونتيجة لدوران التو -1 اسالك الضغط العالي لمتيار الكيربائي الى المستيمك. ربين بعد ان فقد جزءا من ضغطو الى المكثف الذي يقوم بتبريده لغرض و يتجو البخار بعد خروجو من الت -. لعممية تسمى بدورة رانكين.ىذه ا ان تكثيفو وتحويمو الى الحالة السائمة ليعود مرة اخرى الى المرجل. ولة في البحثاالخواص الفيزيائية والكيميائية المتن وبالتالي فانيا في ىذا البحث تم التطرق الى ثمان محددات توثر عمى بيئة النير والكائنات التي تعيش فيو، د الصمبة، المواد الصمبة ثر عمى البيئة ككل. وىذه المحددات ىي: الرقم الييدروجيني، العسرة، القاعدية، المواتؤ العالقة، التوصيل الكيربائي، الكمورايد، العكورة. وفيما يمي شرح مبسط الثر كل محدد من ىذه المحددات عمى :ىذا المجال تباالعتماد عمى الدراسات التي تتناول النير واالسماك والنباتات واالحياء االخرى التي تعيش فيو م الييدروجيني ىو مقياس لدرجة حامضية او قاعدية عينة ما، وفي مجال : الرقphالرقم الييدروجيني -0 ماء الخارج من محطة المعالجة او ماء النير. ويعرف الرقم نة ىي نموذج من الماء سواء كان الالبحث فان العي ، او 0 الييدروجيني عمى انو معكوس لوغارتيم تركيز ايون الييدروجين الموجب في الماء كما في المعادلة رقم .[riche: 2006] 9الييدروجين كما في المعادلة رقم الموغارتيم السالب لتركيز ايون ph=log[1/h+] (1) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 572 ph=-log[h+] (2) حيث: phالرقم الييدروجيني : h+لتر(\: تركيز ايون الييدروجين بـ )غم مكافئ ، [smith: 1984] 0.5مياه المطر تكون عادة حامضية معتدلة حيث تكون قيمة الرقم الييدروجيني ليا ان ىذا المدى يعتبر جو ، و 7.0-5.0اما المياه الجارية )االنيار( تكون قيمة الرقم الييدروجيني ليا ضمن المدى مثالي لنمو اغمب االحياء النيرية. ان الرقم الييدروجيني لمنير عادة يتاثر بطبيعة التربة المار خالليا، فالتربة الجيرية تسبب رقم ىيدروجيني عالي، بينما تسبب التربة ذات المحتوى العضوي رقم ىيدروجيني منخفض. كما ان غاز ثاني اوكسيد الكربون يؤثر عمى الرقم الييدروجيني، فعند اختالط ىذا الغاز مع الماء فان الرقم الييدروجيني سوف ىو االخر ينخفض. ان الرقم الييدروجيني لمنير لو تاثير كبير عمى االحياء التي تعيش في النير. فالتقمب الكبير في الرقم ء التي تعيش في النير. ان الييدروجيني لمنير خارج المدى االعتيادي يسبب ضغوطات عمى كافة االحيا انخفاض الرقم الييدروجيني تحت المستوى المطموب سوف يسبب قتل االسماك وذلك بتعريض انظمتيا الحيوية ي الى فشميا وتصبح غير قادرة عمى مواجية االمراض. وكذلك الحال عند ارتفاع الرقم لالى االجياد وبالتا يكون مصاحبا الرتفاع درجة حرارة النير فانو يسبب في الييدروجيني عن الحد المطموب وخصوصا عندما زيادة نسبة االمونيا في الماء والتي تسبب تسمم السمك. كما ان الرقم الييدروجيني المنخفض يسبب بتغير نوعية االواصر بين العناصر الثقيمة الموجودة في الماء والتي تسبب تسمم االحياء المائية. ويؤثر ارتفاع .[riche: 2006] م الييدروجيني كذلك عمى كمية المواد الغذائية المتوفرة لمنباتات النيريةوانخفاض الرق . وتتولد )الكالسيوم والمغنيسيوم( العسرة: تعرف العسرة عمى انيا تركيز االيونات المتعددة الموجبة في الماء -9 ين العنصرين مثل الترب الجبسية ىذه االيونات في مياه النيرعن طريق جريان النير في الترب الغنية بيذ . مياه المطر والمياه المقطرة تعتبر مياه قميمة العسرة (dolomite)والدولومايت (calcite)وطبقات الكالسايت النيا خالية من ىذه االيونات تقريبا. رىا عمى االسماك ي تأثيتتمثل االثار البيئية لمعسرة ف. عمى االنسان ةيصحواقتصادية و بيئية اتمعسرة تأثير لان من خالل اختالل توازن المياه الداخمة والمنضوحة من جسم الكائن وعدد من اشكال الحياة المائية االخرى تصنيف 0الجدول لتر. ويبن \(ممغم100-000. ان مدى العسرة االكثر مالئمة لالسماك النيرية ىو)النيري [campbell :2010] .المياه حسب عسرتيا ثار االقتصادية في المبال المصروفة من اجل ازالة العسرة ليتسنى لمصابون تكوين الرغوة في حين تتمثل اال والتخمص من طبقة كاربونات الكالسيوم التي تتكون عمى السطوح المعرضة لممياه العسرة كالحنفيات والمراجل. 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 ص عمى انو قد تؤدي العسرة النسان ولكن الدراسات الحديثة تنعمى ا اكيدة لمعسرة سمبيةصحية ال توجد اثار .الى امراض القمب والشرايين القاعدية: ان القاعدية بحد ذاتيا ليست مموث. ويمكن تعريف القاعدية عمى انيا كمية المواد الكمية -1 الموجودة في الماء والتي ليا القابمة عمى معادلة االحماض. لنيرية، فالقاعدية المعتدلة تمنع الرقم الييدروجيني لمياء ان لمقاعدية تاثير كبير عمى حياة االسماك واالحياء ا النير من التغير المفاجئ كما تجعل المياه اقل تاثرا باالمطار الحامضية. في حين القاعدية المرتفعة تعتبر ياه. سامة لكثير من اشكال الحياة، وازديادىا يسبب الطعم الغير مرغوب فيو وتقميل فعالية الكمورين في تعقيم الم اضافة لذلك ان القاعدية الزائدة تؤثر في عممية الري اذا كانت قاعدية مياه الري اكبر من قاعدية التربة لتر في حين اقصى قيمة مسموح بيا \ممغم 900المحيطة بالنبات. ان القيم المرغوب بيا لمقاعدية اقل من .[cai:2010]لتر \ممغم 500ىو صطمح المواد الصمبة الكمية الى المواد المذابة والمواد العالقة في عينة من المواد الصمبة الكمية: يشير م -. ان المواد الصمبة العالقة سيتم التطرق ليا بشكل الماء، وىو مصطمح مرتبط بالعكورة والتوصيل الكيربائي. كالسيوم، بيكاربونات منفصل في البحث. اما المواد الذائبة فيي كل المواد الذائبة الموجودة في عينة الماء مثل ال الصوديوم، النترات، الفوسفات، الحديد، الكبريـت وغيرىا من االيونات. ان وجود ىذه المواد بنسبة معينة ضروري لالحياء النيرية. حيث ان عددا من ىذه االيونات الذائبة مثل النتروجين، الفوسفور، الكبريت تعتبر ية لحياة االحياء النيرية.المكون االساسي لمجموعة من المركبات الضرور ان التركيز الزائد لممواد الصمبة في مياه النير يسبب تردي نوعية المياه ومشاكل بالتوازن المائي لمكائنات :liu] المائية. في حين ان التركيز المنخفض لممواد الصمبة يؤدي الى تقميل معدالت نمو االحياء المائية 2006]. مجموع الحبيبات الرممية والطينية والمواد العضوية المحمولة بواسطة مياه : عبارة عن المواد الصمبة العالقة -0 لتر. ان التراكيز العالية \كيز بوحدات ممغماقاس المواد الصمبة العالقة كتر تالنير او المتحركة فوق قاع النير. يث ان التراكيز العالية تحد من لممواد الصمبة العالقة يسبب اضرار لمكانئات المائية والنير عمى حد سواء. ح الرؤية الجيدة كما انيا تسبب صعوبة التنفس لمكائنات النيرية كما انيا تسبب اضرار اقتصادية عند اسياميا في . [farrell-poe: 2005] تغيير مجرى النير سنتمتر \وتقاس بوحدات مايكوسيمنس توصيل التيار الكيربائيقابمية المادة عمى التوصيل الكيربائي: ىو -5 [ms/cm]عمى التوصيل الكيربائي. القدرة . ان االيونات مثل الصوديوم والبوتاسيوم والكمورايد تعطي الماء 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 الى كمية حيث يشير التوصيل الكيربائي في الماء، ويعتبر التوصيل الكيربائي مقياس لكمية االمالح المذابة . [fortner: 2003] من قياس كال عمى حدة االمالح الكمية المذابة بدال ونقاس بوحدات ، وىواحد اىم االيونات السالبة في الماء(-cl)الكمورايد :الكمورايد ىو ايون الكمور السالب -2 وتأتي خطورة .لتر. تحتوي مياه االنيار عمى نسب مختمفة من الكمورايد بسبب بزل مياه البمدية الى االنيار\ممغم يد من تسببيا في حرق حافات اوراق النباتات عند وجودىا بتراكيز عالية في مياه االنيار. وتشير الكمورا .[lewis: 1989]لتر \ممغم000الدراسات الى ان النسب االمينة لمكمورايد ىي لما او امكانية مرور الضوء خاللو، وتعتبر مقياس العكورة: تعرف العكورة عمى انيا مقياس لنقاوة المياه -7 nephelometric turbidity units [ntu] ، وتقاس بوحداتيحتويو الماء من حبيبات ومواد صبغية عالقة . ان زيادة العكورة يؤدي الى زيادة درجة حرارة secchi depth او jackson turbidity units [jtus]او لمعكورة تأثيرات بيئية ان الماء. الماء بسبب امتصاص الحبيبات العالقة لمحرارة ومنعيا الضوء من اختراق وصحية سمبية، حيث تقمل من مدى رؤية االسماك فتقل قدرتيا عمى االفتراس وكذلك تكون ممجأ لمسببات [irvine: 2002].المرض من المعقمات معدل القيم السنوية لبعض الخصائص الفيزيائية والكيميائية لمخمفات محطة المسيب الحرارية. 4الجدول ويبين .المحددات البيئية لممخمفات المطروحة من محطات الطاقة الحرارية 3الجدول ويبين المواد وطرق العمل تضمنت الدراسة زيارة ميدانية إلى محطة المسيب الحرارية والتعرف عمى أقساميا. وتم جمع العينات من مواقع م( والمواقع 00المحطة الحرارية بـ ) محددة من مجرى نير الفرات وىي خمس مواقع: الموقع األول قبل مأخذ . (out flow)م عن دفق المحطة0000م، 000م، 900م، 00األخرى تبعد عينة من كل موقع. تم تثبيت وقت اخذ العينات خالل 09العينات من منتصف نير الفرات وقد أخذت ت ذأخ باستعمال جياز ntuدات ( . وقيست العكورة بوح00:00( إلى الساعة )2:00ساعات النيار من الساعة ) turbidity meter, hach2100 وقيس الرقم اليدروجيني باستخدام الجياز ،ph meter, hanna أما ، المواد الصمبة الذائبة فقيست بطريقة الترشيح االعتيادية ثم التجفيف وحساب فرق الوزن، وقيست المواد الصمبة ec meter, bischofتوصيل الكيربائي فاستخدم جياز الكمية بطريقة التجفيف وحساب فرق الوزن، أما ال لقياسو، واستخدمت طريقة التسحيح لقياس كل من العسرة والكمورايد والقاعدية باستخدام محمول نترات الفضة واستخدام صبغة كرومات البوتاسيوم كدليل. 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 525 النتائج والمناقشة إلى شير 9002نير الفرات من شير كانون الثاني نتائج تحميل مياه 9 الشكلإلى 4 شكلتبين األشكال من . يالحظ حدوث تغيرات عمى بعض الخواص الفيزيائية والكيميائية لمياه النير عمى مدار 9002كانون األول يظير تأثير المحطة عمى الرقم الييدروجيني. عمى سبيل المثال كان الرقم الييدروجيني 4 الشكلالسنة. ففي م 00بعد المحطة بـ 7.9وانخفضت ىده القيمة لتكون 2وليا المحطة لشير كانون الثاني لمياه النير قبل دخ بعد المحطة بـ 7.2م ومن ثم 000بعد المحطة بـ ..7و م900بعد المحطة بـ 7.1وعادت لترتفع لتكون ثاني. وأعمى قيم . وكان سموك قيم الرقم الييدروجيني مع المسافة لبقية األشير مشابيا لشير كانون الم 0000 )فمثال كانت قيمة لمرقم الييدروجيني قد سجمت في شير تموز وأب وأيمول وأوطأ قيم في شير آذار ونيسان . ان االسباب التي ادت ألشير آذار ونيسان( 7.7ألشير تموز وأب وأيمول وكانت ..2 الرقم الييدروجيني ود الى تباين تصريف النير من شير الخر، اما تباين الى ىذا التباين في الرقم الييدروجيني بين االشير يع معادلة النير لقيمة الرقم الييروجيني مع نتيجة لالرقم الييدروجيني في الشير الواحد خالل مجرى النير فيو .هامتداد قيمتيا من تدايظير تأثير المحطة عمى عسرة مياه نير الفرات. ففي شير كانون الثاني مثال ز 3 الشكلفي وتنخفض القيمة لتكون م00بعد المحطة بـ لتر \ممغم 10.إلى م00قبل المحطة بـ لتر \ممغم 102 عمى م0000و م000 و م900بعد المحطة بـ لتر\ممغم 170 و لتر \ممغم 127 و لتر \ممغم .0. المحطة كانت قيمة العسرة ) فمثال قبل وأوطأ القيم في شير نيسان وكانت أعمى القيم في شير أب التوالي. لشير نيسان( ويرجع ىذا التباين في قيم العسرة لتر \ممغم 920يا لشير اب وكانت قيمت لتر \ممغم .11 الى التباين في تصريف النير والتباين في نوعية المياه المطروحة من المحطة. 010 كانت القاعدية قبل المحطة تأثير المحطة عمى القاعدية. ففي شير آذار مثال 2 الشكليتضح من ، .00وأخذت بعد ذلك بالتناقص إلى م00بعد المحطة بـ لتر \ممغم 005 وازدادت لتصبح لتر \ممغم م عمى التوالي. 0000، 000، 900لتر عمى مسافات \ممغم 0.0.7، 0.2 زداد كمية المواد الصمبة لممياه بعد المحطة يظير تأثر المواد الصمبة في المياه بالمحطة. حيث ت 5 الشكلوفي ثم تبدأ بالتناقص تدريجيا كمما ابتعدنا عن المحطة. . حيث كانت القيم المقاسة عمى 6 الشكلولمالحظة مدى تأثر المواد الصمبة العالقة لممياه بالمحطة يستعرض ومن ثم القيم المقاسة عمى م 00 م( تمثل أعمى القيم ومن ورائيا القيم المقاسة قبل المحطة بـ900مسافة ) مع بقية القيم. م900 مع مالحظة تداخل القيم المقاسة عمى مسافة م0000 و م00مسافة يظير تأثير المحطة عمى خاصية التوصيل الكيربائي لمياه نير الفرات. حيث يزداد التوصيل 7 الشكلوفي الخاصية باالنخفاض تدريجيا كمما ابتعدنا عن المحطة. الكيربائي لممياه بعد دخوليا المحطة ثم تبدأ ىده يالحظ تأثير المحطة عمى نسبة الكمورايد في المياه. حيث تزداد ىده النسبة بعد المحطة ثم تبدأ 8 الشكلوفي اقل من قيميا قبل المحطة. م0000 بالتناقص كمما ابتعدنا عن المحطة لتصل نسب الكمواريد عمى مسافة 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 يظير تأثير المحطة عمى عكورة مياه نير الفرات. حيث تقل عكورة المياه بعد المحطة ثم تبدأ 9 لالشكوفي القيم يرجع الى المواد المطروحة من قبل المحطة التغير في االزدياد كمما ابتعدنا عن المحطة. ان سبب ىذا ب .في النير التوصيل الكيربائي لمياه الري، األمالح الدائبة ىنالك عدة تصنيفات لمياه الري اعتمادا عمى أسس مختمفة منيا مواصفات مياه الري اعتمادا عمى التوصيل (2) الجدولالكمية، نسبة امتصاص الصوديوم. و يظير في . عند مقارنة القيم التي [rowe and abdel-magid: 1995]الكيربائي لمياه الري واألمالح الدائبة الكمية حيث تتراوح قيم (class2, good)تبين أنيا تقع ضمن المدى الثاني 5 لتم الحصول عمييا من الشك سم. باستثناء قيم التوصيل لشير أب وأيمول عمى \مايكروموز 200-900 التوصيل الكيربائي بين سم عمى التوالي مما يجعل المياه في ىدا \( مايكروموز 209,200م( بعد المحطة حيث كانت القيم )00مسافة) . مع مالحظة إن (class3,permissible 1)وليدين الشيرين ضمن التصنيف الثالث لمياه الري الموقع 9المياه قبل المحطة كان ليا األفضمية عمى المياه بعد المحطة التي كانت اقرب إلى الحدود العميا لمتصنيف سم. \مايكروموز 200أي (class2, good)لمياه الري االستنتاجات وذلك بسبب المخمفات محطة الحرارية عمى جميع المتغيرات المعتمدة في الدراسةظير تأثير ال .0 . المطروحة من قبل المحطة الى النير يتالشى تأثير المحطة كمما ابتعدنا عنيا، وتقارب المتغيرات المدروسة بعد المحطة إلى قيميا قبل .9 .روف البيئية عمى مدار السنةالظ بسبب تباين م(، مع ظيور بعض الشواذ0000المحطة بعد مسافة ) ، (class2,good)تصنف مياه نير الفرات قبل وبعد المحطة من ناحية الري عمى أنيا من النوع الجيد .1 باستثناء شيري أب، وأيمول. التوصيات تفعيل محطة المعالجة الخاصة بالمحطة الحرارية . .0 زيائية والكيميائية التخاذ إجراء تنظيم جدول زمني لسحب نماذج من النير لغرض معرفة خواصو الفي .9 سريع في المعالجة عند ظيور قيم غير مالئمة. إجراء دراسة حول تأثير المحطة الحرارية عمى العناصر الثقيمة لمنير. .1 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 المصادر الطفيمي ، محمد عبد مسمم ، " تعيين كفاءة أحواض الترسيب والمرشحات لعدد من محطات التصفية في (0 . 0222، 0، العدد .مجمة جامعة بابل ، العموم اليندسية ، المجمد محافظة النجف " ، عبد العباس ، محمد عبد المجيد ، " دراسة تقييم نوعية مياه شط الكوفة لالستخدامات المنزلية واإلروائية " (9 ول لكمية المجمة العراقية لميندسة الميكانيكية وىندسة المواد ، عدد خاص لبحوث المؤتمر العممي السنوي األ .c ،9002 اليندسة / العدد 3) bauer, henry, monitoring water quality and fecal coliform bacteria in the upper susquehanna river, suny oneonta bio. fld sta., suny college at oneonta, 2010. 4) cai, wei‐jun, xinping hu, wei‐jen huang, li‐qing jiang, yongchen wang, tsung‐hung peng,2 and xin zhang3, alkalinity distribution in the western north atlantic ocean margins, journal of geophysical research, vol. 115, 2010. 5) campbell, jarryd, dan peterson, determination of water hardness from common water sources using flame atomic absorbance spectrometry, concordia college journal of analytical chemistry 1 (2010), 4-8. 6) canada, scott; g. cohen, r. cable, d. brosseau, and h. price (2004-10-25). "parabolic trough organic rankine cycle solar power plant".2004 doe solar energy technologies (denver, colorado: us department of energy nrel). retrieved 2009-03-17. 7) farrell-poe,kitt, water quality & monitoring,2005. 8) fortner, everett, gunter faure, possible contamination of the sandusky river by wastewater discharge by bucyrus, ohio, ohio journal of science: volume 103, issue 4 (september, 2003). 9) howick, gregory l., jerry wilhm, turbidity in lake carl blackwell: effects of water depth and wind, proc. okla. acad. sci. 65:51-57, 1985. 10) irvine',k.n., e.l. somogye ', and g.w. pettibone , turbidity, suspended solids, and bacteria relationships in the buffalo river watershed, middle states geographer, 2002, 35:42-51. 11) james, d.w., r.j. hanks and j.h. jurinak. modern irrigated soils. john wiley and sons, ny, 1982. 12) kapoorie ,r.r., s. kumar, k.s. kasana, an analysis of a thermal power plant working on a rankine cycle: a theoretical investigation , journal of energy in southern africa. vol. 19, no. 1. february 2008. 13) karikari , a. y. and o. d. ansa-asare, physico-chemical and microbial water quality assessment of densu river of ghana, csir-water research institute,2004. 14) lewis, william m.,james f. saunder, concentration and transport of dissolved and suspended substances in the orinoco river, biogeochemistry journal 7 usa: p203-p240, 1989. 15) liu, j.p., a.c. li, k.h. xu, d.m. velozzi, z.s. yang, j.d. milliman, d.j. demaster, sedimentary features of the yangtze river-derived along-shelf clinoform deposit in the east china sea, continental shelf research 26 (2006) 2141–2156. 16) riche, estelle, aude carrié, nicolas andin, and stéphane mabic, high-purity water and ph, american laboratory,june/july 2006. 17) rowe, d.r. and i.m. abdel-magid. handbook of wastewater reclamation and reuse. crc press, inc. 550p, 1995. 18) smith, s. j., a. n. sharpley, and r. g. menzel, the ph of rainfall in the southern plains, proc. okla. acad. sci. 64:40-42 (1984). http://www.nrel.gov/csp/troughnet/pdfs/37077.pdf http://www.nrel.gov/csp/troughnet/pdfs/37077.pdf 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 19) who , world health organization, " guidelines for drinking water quality ". first addendum to third edition, vol. 1, recommendations, geneva, 2006. 20) william m. lewis, jr & james f. saunders, constration and transport of dissolved and suspended substances in orinoco river, biogeochemistry 7: 203-240, 1989. يةلمخمفات محطة كيرباء المسيب الحرار ( معدل القيم السنوية لمخصائص الفيزيائية والكيميائية4جدول رقم) القيمة الوحدة الخاصية 9,5 بال phالرقم الييدروجيني 261 لتر \ممغ العسرة 071 لتر \ممغ القاعدية 895 لتر \ممغ المواد الصمبة 212 لتر \ممغ المواد الصمبة العالقة 771 سم \مايكروموز التوصيل الكيربائي 355 لتر \ممغ الكمورايد ntu 24 العكورة [campbell: 2010]( تصنيف الماء حسب عسرتيا0جدول رقم) indication concentration as caco3 soft water 0 to 60 ppm moderately hard water 60 to 120 ppm hard water 120 to 180 ppm very hard water >180 ppm 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 رية( المحددات البيئية لممخمفــــــــــــــــــــات المطــــــــــــــروحة من محطات الطـــــــــــاقة الحــــــــــــــــــــــرا 3ل ) الجدو (electronic code of federal regulations: 2011) [rowe and abdel-magid: 1995](مواصفات مياه الري 2جدول) concentration, total dissolved solids classes of water gravimetric ppm electrical conductivity μmhos* 175 250 class 1, excellent 175-525 250-750 class 2, good 525-1400 750-2000 class 3, permissible1 1400-2100 2000-3000 class 4, doubtful2 2100 3000 class 5, unsuitable2 *micromhos/cm at 25 degrees c. 1leaching needed if used 2good drainage needed and sensitive plants will have difficulty obtaining stands pollutant or pollutant property maximum for any 1 day average of daily values for 30 consecutive days concentration in mg/l iron, total 7.0 3.5 manganese, total 4.0 2.0 tss 70 35 ph 1 1 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 527 (google earth)موقع محطة المسيب الحرارية لتوليد الطاقة الكيربائية :( 0الشكل ) phالرقم الييدروجيني :(4الشكل) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 العسرة :(3الشكل) القاعدية :(2الشكل) اد الصمبةالمو :(5الشكل) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 المواد الصمبة العالقة :(6الشكل) التوصيل الكيربائي :(7الشكل) الكمورايد :(8الشكل) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 522 العكورة :(9الشكل) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 821 degradation of organic dyes using photo-catalytic technique m.sc. ayad dari jaafar department of chemical engineering university of technology e-mail: ayad.dari@yahoo.com received 15 december 2014 accepted 3 february 2015 abstrct the present investigation is concerned to study the prepared of nano composite catalyst of titanium dioxide and carbon nanotube (tio2/cnt) based on photo-catalysts process. the synthesized composite catalyst was characterized by brunauer, emmett and teller (bet), scanning electron microscopy (sem), x-ray diffraction (xrd), xrf and raman spectroscopy. moreover, the nano composite catalyst was used as a dye to degradation of contaminated water that containing organic pollutants. the photo-catalytic degradation process was carried out at different operational parameters, (initial concentration of hydrogen peroxide h2o2 of the medium, mixing speed, and flow rate for methylene blue (mb, c16h18n3scl.3h2o) dye). the nano titanium dioxide / carbon nanotubes (tio2/cnt) composite showed greater photo-degradation activity under solar and ultraviolet (uv) lamp. keywords: photo-catalytic, carbon nanotubes, titanium dioxide, dyes degradation, nano technique. المحفز بالضوءاغ العضويه بتقنية االصب تكسر راياد داري جعفم.م قسم الهندسة الكيمياويه الجامعة التكنولوجية الخال صة ز تحفيلعملية ال (tio2/cnt)تحضير العامل المساعد النانوي المركب من اوكسيد التتانيوم وانابيب الكاربون دراسةالبحث يتناول (, و تقنيات betخصائص العامل المساعد بقياس المساحة السطحية للمركب المحضر باستخدام طريقة ) دراسةتم , حيثبالضوء العامل المساعد النانوي المركب عالوة على ذلك استخدم. ومقياس رامان xrd,xrf( , semالمجهر االلكتروني الماسح) عملية المحفز في كسرعملية الت دراسة عدة عوامل مؤثرة على تمت بعد ذلك . ملوثات المياه العضويه مثل االصباغكسير لت والعامل (, والجريان الحجمي للصبغةrpm) (, وسرعة الخلطmg/l) h2o2 لبروكسيد الهيدروجين ) التركيز االبتدائي للضوء .واالشعة الفوق البنفسجية اشعة الشمسالعامل المساعد النانوي كفاءة عالية تحت تاثير اظهر . ( (l/min) المساعد الصبغة, تقنية النانو. كسر, كاربون نانوتيوب, اوكسيد التيتانيوم , تالمحفز بالضوءمفاتيح الكلمات: mailto:ayad.dari@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 821 introduction degradation of organic pollutants and dyes such as methylene blue, bromo phenol blue, and chicago sky blue from industrial waste water remains as a challenge because of low visible light photo catalytic activity of metal oxides and sulphides [1] . the possibility of combining heterogeneous catalysis with solar technology to achieve complete mineralization of toxic organic pollutants has received much attention [2] . multi-walled carbon nanotubes (mwcnts) could be considered as a good support for materials with field emission displays and photo-catalytic properties. on the other hand, a combination of titanium dioxide (tio2) and mwcnt could create many active sites for the photo-catalytic degradation [3] . advanced chemical treatment processes are used many times to achieve better treated water quality for use and also when the necessary standards are not being met with the conventional means of treatment [4] .an advantage of photo-catalytic method includes low temperature, low expenses and also radically low level of energy consumption in this method [5] . won c. o. and ming l. c. were used the activated carbon materials and tio2 composites by mechanical and hydrothermal treatment while demonstrated very good performance in the photocatalytic degradation of methylene blue [6] . the ferrous ion and tio2 units were covered on the activated carbon surface and were developed through a deposition process of a sol-gel method. the ferrous–ac/tio2 samples show a strong degradation and can efficiently decompose the methylene blue (mb) solution under visible light (za-da meng, kan zhang) [7] . sonal s., rimi sh., els., a comparative photo-catalytic study of znfe2o4 and (znfe2o4/multi wall carbon nano tubes) nano composite clearly indicated the enhancement of photo-catalytic activity in (znfe2o4/ multi wall carbon nano tubes) nano hybrid. mb was almost 84% degraded in the presence of znfe2o4 photo-catalyst, while 99% degradation was observed in case of znfe2o4/mwcnt composite after irradiation for 5 hours in the visible light [8] . in this work, the nano composite catalyst of titanium dioxide and carbon nano tube (tio2/cnt) was prepared based on photo-catalysts process. the synthesized catalyst was characterized using a different analytical technique. the effect of nano photo-catalytic tio2/cnt composite was also evaluated by methylene blue (mb) degradation in aqueous solution under an uv lamp and solar. experimental work catalysts preparation nano-tio2 (5 gm) was added to the aqueous fe (no3) and stirred for 3 hrs. resultant suspension was filtered and solids were washed with d.i. water until its ph reaches 7. a washed solid was dried in vacuum at 60 0 c for 2 hrs to obtain yellowish tio2 powder loaded with fe 3+ ions. it was coated on substrate and used in thermal furnace as a catalytic substrate. the above prepared catalytic substrate was placed at center of quartz tube in furnace at temperature 300 0 c – 800 0 c. it was then catalytically (fe +3 ) deposited over tio2 surface as cnts, (fig.1). catalysts characterization the scanning electron microscopy (sem) of carbon nanotubes and carbon nanotubes-tio2 composite explain the different morphology between the two prepared samples. the sem images of 10,000 magnifications of the prepared catalysts are shown in (fig.2) than indicates that the pure carbon nanotubes and composite materials present a homogeneous distribution of tio2 on the cnts. so it was considered that nano cnt-tio2 composites could have much more activity and show an excellent photo-catalytic activity. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 831 the xrd (model panalytical x'pert pro mpd) patterns of the nano tio2/cnt composites were displayed in (fig.3). the patterns demonstrate the highly crystalline nature of the composites. the characteristic peaks for cnt at position of 2ɵ= 26.5°. and you could see peak tio2 at 2ɵ= 43.5°. bet surface area was measured using a surface area analyzer (q-surf 9600, usa) were used to observe the surface of the tio2/cnt composites is 33 m 2 /gm. from (fig.4) could be observed that the xrf for pure carbon nanotubes prepared until to 98% graphite. (fig.5) shows raman spectroscopy vs wave number (cm -1 ) revealed invaluable insights into the purification of nanotubes. g-band (1568 cm −1 ) corresponded to the confirmation of mwcnts. defect induced d-band (1350 cm −1 ) was minimized after purifying cnts. photo-catalytic degradation of dye the photo-catalytic effect of nano tio2/cnt composite was evaluated by methylene blue (mb) degradation in aqueous solution under solar and uv lamp (365 nm, 1.2 mw/cm 2 ). before turning on photo-catalytic unit, the solution mixed with composite and h2o2 for 30 min. then, the solution was radiated with photo-catalytic unit, (fig. 6). sample of methylene blue (mb) solution were withdrawn at the rate of (0.5, 1, 1.5 and 2 l/ min) and concentration hydrogen peroxide h2o2 (200,300,400 and 500 mg/l).the agitation mixing (100, 250, 750 and 1400 rpm) with 50 mg/l from composite catalyst and ph=7 for mixture to degradation the dye. results and discussion (fig.7) shows, the degradation of the methylene blue mb (ppm) versus uv illumination time (min) at different mixing agitation (rpm). from these figure, the prepared catalysts show the high photo-catalytic activity and degradation of methylene blue (mb). the increment of nano (tio2/cnt) mixing in the composite (100, 250, 500, 750 and 1400 rpm) leads to increased photo catalytic activity and degradation ability. during initial 105 minutes the high degradation at mixing speed 1400 rpm at constant (flow rate for mixture 1.5 l/min, ch2o2= 300 mg/l, ccnt/tio2= 50 mg/l and ph=7) is 0.74, the dyes were rapidly degradation in all case due to the effect of the solid nano materials. (fig. 8) shows, the photo-degradation ability of the samples also improved with the increment of flow meter recycles for mixture (0.5, 1, 1.5 and 2 l / min). this indicates that the increasing flow rate for mixture (mb dyes with nano (tio2/cnt) composite) increase degradation of methylene blue (mb) until 1.5 (l/min) is 0.74. then increasing flow rate to 2 (l/min) the degradation of dyes is 0.69 because at 1.5 (l/min) the better flow rate to distribution in photo-catalytic reactor and when this flow, the solar energy absorbed by nano composite is very sufficient to degradation the dye. carbon nanotubes cnts might accept the photo-induced electron (e-) into the conduction band of the tio2 particles by (uv + solar) irradiation (eq.1). it is considered that electrons in cnts are transferred to the conduction band in the tio2 particles. in this time, the electrons in conduction band might react with (o2 .). simultaneously, a positive charged hole (h+) might be formed with electron transfer from valence bond in tio2 to cnts (eq.3). the positive charged hole (h + ) might react with oh derived from h2o. with this understanding, the role played by cnts can be illustrated by injecting electrons into tio2 conduction band under (uv + solar) irradiation and triggering the formation of very reactive superoxide radical ion (o2 . ) ((eq.2 and hydroxyl radical oh . ) (eq.4)). consequently, both radical group (superoxide radical ion (o2 . ) and hydroxyl radical (oh . )) are responsible for degradation of the organic compound as mb. ⃗⃗ ⃗⃗ ⃗⃗ ⃗⃗ ⃗⃗ ⃗⃗ ⃗⃗ ⃗⃗ ⃗ (1) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 838 ⃗⃗⃗⃗ ⃗⃗⃗⃗ ⃗⃗ ⃗ (2) ⃗⃗ ⃗⃗ ⃗⃗⃗⃗ ⃗⃗ ⃗⃗ (3) (4) plots the variation in dye degradation against hydrogen peroxide concentration in solution keeping all other parameters unchanged. different concentrations of (200,300,400 and 500 ) were added to study the effect of concentration on the degradation process. the rate of degradation goes on increasing with the increase in concentration of h2o2 and becomes maximum at 300 mg/l (degradation of methylene blue is 0.74) and then starts decreasing with further increase in concentration of h2o2 (degradation of methylene blue is 0.62, 0.45 at ch2o2 is 400 and 500 mg/l sequentially) .the addition of h2o2 may play an important role in the limitation rate of photogenerated hole-electron pairs that contribute to degradation rate mb dyes, (fig. 9). as can be seen, the degradation increases with increasing initial concentration of , as the formation of hydroxyl radicals is insufficient, this may explain the ability of to trapping the electrons preventing the electron-hole recombination hence decrease the chance for formation of radicals on the surface of the catalyst. however, as the initial concentration of increases beyond a certain value (300 , the increase in decomposition rate becomes less. this is because at higher concentration, more is produced leading to a faster oxidation rate. however, the excess free radicals prefer to react with the excess of rather than with the dye. conclusion the synthesis and characterization of nano tio2/cnt composites thermally derived from cnts by an improved oxidation method because the conductive structure of the cnt scaffolds might facilitate the separation of the photo-generated electron/ hole pairs at the cnt-tio2 interface leading to the faster rates of photo-catalytic oxidation. in addition, the application of anodic potentials on irradiated tio2/cnt composites films might result in a further enhancement. the structural variations, elemental analysis and surface morphology were investigated through preparation of tio2/cnt composites under ultraviolet uv and solar light irradiation. the tio2/cnt composite showed greater photo-degradation activity under uv and solar light irradiation. changes of color disappearance for relative methylene blue (mb) degradation concentration under uv and solar light irradiation in the solution as a function of time was studies. the mb degradation with cnt/tio2 composite was carried out to observe the uv photolysis effect. refrences [1] sonal s., rimi sh., charanjit s., bansal s., "enhanced photocatalytic degradation of methylene blue uing znfe2o4/ mwcnt composite synthesized by hydrothermal method", indian journal of materials science, hindawi, http://www.hindawi.com, volume 2013. [2] noureddine b., samir q., ali a., yhya a.,"solar photocatalytic degradation of textile on dynamic pilot plant using supported tio2" ,the arabian journal for science and engineering, vol35, no.2a, 2010. [3] won-chun o., ming-liang ch.,"synthesis and characterization of cnt/tio2 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 832 composites thermally derived from mwcnt and titanium (iv) n-butoxide", department of advanced materials & science engineering,vol.29 , 356-706. 2008. [4] kumr r., singh r.n., municipal water and wastewater treatment, environmental engineering series, 93, 2014. [5] ehrampoush m. h., moussavi gh. r. , ghaneian m. t. ,rahimi s. , ahmadian m.," removal of methylene blue dye from textile simulated sample using tubular reactor and tio2/ uv-c photocatalytic process",vol.8, no.1, 2011. [6] won-chen o., ming-liang ch.,"synthesis and characterization of cnt/tio2 composites thermally derived from mwcnts and titanium (iv) n-butoxide", vol.29, no. 1, 2008. [7] za-da m. , kan z. and won-chun o. ,"preparation and characterization and visible light photocatalytic activity of fe-treated ac/tio2 composites for methylene blue", vol.46, 2009. [8] sonal s., rimi sh., charanjit s. and bansal,"enhanced photocatalytic degredation of methylene blue using znfe2o4/ mwcnt composite synthesized by hydrothermal method", indian journal of materials science, hindawi, volume 2013 figure (1): carbon nanotubes deposit it tio2 particles process. furnace 100-1100 0 c quartz tube ceramic basin tio2 particles (hydrocarbon source+ nitrogen)gas control al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 833 figure (2): sem images of the (a) functionalization of carbon nanotubes (b) nano (cnt/ tio2) figure (3): xrd of composite (tio2/ cnt) tio2 cnt b a 2 theta (') intensity al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 831 figure (4): xrf of carbon nanotubes. fig.(5) raman spectra of nano composite figure (5): raman spectra of nano composite d= 1350 cm -1 g=1568 cm -1 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 831 figure (6): photo-catalytic unit. figure (7): the degradation of the methylene blue mb (ppm) with uv illumination time (min) at different mixing agitation (rpm) at constant ch2o2= 300 mg/l and flow rate = 1.5 l/min, ( ph= 7 and ccnt/tio2 = 50 mg/l). 0 0.2 0.4 0.6 0.8 0 50 100 150 d e g ra d a ti o n o f m b uv illumination time min series1 series2 series3 series4 series5 1400rpm 250rpm 750rpm 100rpm 500rpm al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 831 figure (8): the degradation of the methylene blue mb (ppm) with uv illumination time (min) at different flow rate (liter/min) at constant ch2o2= 300 mg/l and mixing agitation = 1400 rpm ,(ph=7 and ccnt/tio2 = 50 mg/l). figure (9): the degradation of methylene blue mb (ppm) with different concentration of hydrogen peroxide h2o2 (mg/l) at constant flow rate =1.5 l/min and mixing =1400 rpm, (ph=7 and ccnt/tio2 = 50 mg/l). 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 50 100 150 d e g ra d a ti o n o f m b uv illumination time min series1 series2 series3 series4 0.5 l/min 1 l/min 1.5 l/min 2 l/min 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 1 دراسة تأثير اضافة االلياف المختلفة لمتراكبة البوليستر على خاصية البلى االلتصاقي م.امل صادق عطا * م.م نورس جبار ناصر * م.م اخالص احمدعبدالرزاق* amalatta13@yahoo.com nawresjabaar@yahoo.com ekhlasah@yahoo.com 2102كانون االول 22ُقبل في 2102تموز 2ًأستلم الخالصة: حيث تم تصنيع ثالث مقاومة البلى االلتصاقي الى راتنح البوليسترعلىالبحث دراسة تاثير بعض االضافات يتناول ومجموعة اخرى تحتوي % راتنج البوليستر الغير مشبع 100مجموعة تحتوي علىوهي مجاميع من المواد المتراكبة والمجموعة الثالثة تحتوي على ( -fiber glass e% الياف الزجاج )30 راتنج البوليستر الغير مشبع +%70 على ومن هذه المواد تم تصنيع عدد من (carbon fiber)% الياف الكربون 30 %راتنج البوليستر الغير مشبع +70 mm(10x10x25.)وبابعاد .astmg-99عينات البلى االلتصاقي وفق المواصفة القياسية متغيرة هي ( تحت تاثير احمال(pin–on-diskقرص( -على –)المسمار بطريقة البلى االلتصاقياختبار اجري n(5,10,15,17.5 وسرع انزالق ) m/sec(1.9, 3.79, 5.96 ) زمن اختبار ثابتو (t= 5 min ) في ظروف معدل البلى كفقدان لوزن العينة بعد االختبار. وحساب عمل جافة وبدرجه حرارة الغرفه وقد زيادة الحمل المسلط والسرعة االنزالقية لجميع انواع المتراكبات بنتائج البحث بان معدل البلى يزداد اظهرتوقد واه و ان عينات البولي استر المقساهمت المواد المضافة في تحسين مقاومة البلى االلتصاقي مقارنة بالمركب االساس .جميع االحمال والسرع عند اقل مقارنة مع االنواع االخرى من المتراكبات و ىمعدالت بلاعطت بالياف الكاربون studying the effect of adding different fiber types to polyester composite on the adhesive wear property mailto:amalatta13@yahoo.com mailto:nawresjabaar@yahoo.com mailto:ekhlasah@yahoo.com 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 2 amal sadiq atta nawres jabar nasser eklas ahmad abd-lrazaq 3@yahoo.comamalatta1 nawresjabaar@yahoo.com ekhlasah@yahoo.com abstract: this paper include studying the effect of adhesive wear of three groups which fabricated of 100% non-saturated polyester resin, 70% non-saturated polyester resin with 30% e -fiber glass, and the third was 70% non-saturated polyester resin with 30% carbon fiber. adhesive wear test have been conducted on specimens which fabricated from material above according to astm g-99 in diminutions (10x10x25) at variable loads(5,10,15,17.5)n ,sliding speed (1.9, 3.79, 5.96) m/min and constant time (5) min using pin on disc method in dry condition at room temperature. wear rate in the experiments was determined as weight loss. the results show that the wear rate of composite specimens increase when the applied load and sliding speed for all types of composites increased. the wear characteristics improved by adding carbon fiber to polyester gives less wear rates compared with other types of composites for all loads and sliding speeds. البولي استر , الياف الزجاج , الياف الكاربون , البلى االلتصاقي. المواد المتراكبة , راتنج الكلمات الدالة : المقدمة : -0 نتيجه البحث العلمي ظهرت الحاجه الى مواد بوليمريه ذات مواصفات معينه اليمكن الحصول عليها من نوع واحد بالمواصفات الصناعيه لهذا ظهرت محاوالت في مزج نوعين او اكثر من المواد والحصول على خليط بوليميري . وتعرف المواد المتراكبه بانها "بناء مكون من مادتين او اكثر ذات مواصفات (9002,د. ضياء)المرغوب بها وان عمليه الدمج هذه (9000,)د. صالح مختلفه تربط مع بعضها بطريقه معينه لتعطي التركيب المرغوب بها " ندسية و فيزيائية تختلف عن خواص المواد الداخله في تركيبها تؤدي الى الحصول على ماده جديده ذات خواص ه وهي بذلك تجمع الخصائص الجيده من مختلف المواد الداخله في تركيبها عالوة على التخلص من العيوب الموجوده .فيها لتكون اكثر مالئمه للتطبيقات الصناعيه ( matrix materialلطور االول يشمل المادة االساس )ويمكن القول ان المادة المتركبه تتكون من طورين هما : ا ( . يرتبط الطورين ببعضهما عن طريق سطح reinforcement materialوالطور الثاني يشمل مواد التقويه ) وقد ظهرت باالونه االخيره االهتمام بدراسه ظاهرة البلى والتي يظهر (9009,سلمان)رابط يدعى السطح البيني mailto:amalatta13@yahoo.com mailto:nawresjabaar@yahoo.com mailto:ekhlasah@yahoo.com 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 3 حيث تعد هذه الظاهرة مهمة (9002,د. ضياء) دورها بشكل واضح في عمليات تشغيل االنظمه الميكانيكيه المتعددة بشكل كبير بسبب تاثيرها السلبي في دقه اداء االجزاء البوليمريه في المكائن حيث يعرف البلى انه " عمليه الفقدان ويعرف ايضا (9009,لعيبي)تكونان تحت تأثير حركه نسبيه " او الخساره في مادة احد السطحين او كليهما عندما انه "عمليه تعريه لسطح المادة الصلبة نتيجة تاثيرها بسطح جسم صلب اخر" وان دراسة البلى للمواد البوليمريه بشكل عام وللمتراكبه بشكل خاص هو بسبب توفره بشكل واسع وخفة وزنه وسهوله تصنيعه ومتانة الجيدة وقله ويقسم البلى الى االنواع االتية. .(9002,د. ضياء)ل االحتكاك له وتحمله االحمال العاليهمعام abrasive wearالبلى االحتكاكي -أ erosion wearبلي التعرية -ب adhesive wearالبلى االلتصاقي -ج في حالة انزالق السطوح على بعضها البعض وتحت تاثير الحمل وقد تناول البحث البلى االلتصاقي حيث يحصل بحيث يكون الضغط على النتوءات المتماسكه على درجه كبيره تكفي الحداث تشوه لدن موضعي حيث يحصل التصاق ذو درجة عالية للسطوح النظيفه او الخاليه من االكاسيد بين عدد قليل من النتوءات بسبب وجود قوة جذب السطحين ، ونظرا الن مساحة التالمس الحقيقية اقل بكثير من مساحه التالمس الظاهريه فان الضغط بين ذرات يكون عالي عند قمم النتوءات المتالمسة الضعيفة . -لتصاقي وكما يلي:ضافات على مقاومة البلى األبعض األ ثيرأوقد درس العديد من الباحثين ت درس مقاومة البلى االلتصاقي لنماذج محضرة من خليط بوليمري )راتنجات (9002)د. ضياء و عبد الحسين ( باستخدام محلولين احدهما %10/%10/%80االيبوكسي مضافا اليه البولي استر والنوفوالك( عند نسبة خلط ) لى يزداد حامضى واالخر قاعدي وان االختبار اجري عند حمل متغير وسرعة انزالقية متغيرة وقد وجد ان معدل الب ( وكذلك السرعة االنزالقية وقد اكد على دور المحلول القاعدي في عملية 20nبزيادة الحمل المسلط الى مقدار ) الخلط في تحسين مقاومة البلى خاصة عند غمر الراتنج لفترة طويلة مقارنة بالمحاليل الكيمياوية الحامضية التي (naoh,hcl)ت من قبل الباحثين في محلول تؤدي الى خفض في صالدة المركب والتي ايضا درس .0.5n)وبتركيز) قاما باضافة قشورالرز كمادة مدعمة الى راتنج البولي استر بوصفها مادة اساس للمادة (9009)العيبي , يونس ل , واستنتجا زيادة معدل البلى عند زيادة كل من المتغيرات الحم المتراكبة ودراسة خواص البلى االلتصاقي المسلط ومسافة االنزالق وزمن االختبار واشارا الى ان اعلى قيمة لمعدل البلى عند حمل متغير هي عند الحمل ( اما اعلى قيمة عند تغير السرعة وثبوت الحمل والزمن فكانت عند السرعة 1.91gm/cm( نيوتن اذ بلغت )90) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 4 عند الزمن المتغير فقد بلغ معدل البلى اما (1.43gm/cm)حيث ان معدل البلى بلغ (4cm)االنزالقية 5.33gm/cm) ( عند زمن مقداره )دقيقة(. 6 hasim pihtili (9002 )( قام بدراسة تاثير تغيير المادة االساس على البلى باستخدام طريقةwear tester (a block on-shaft مع االلياف الزجاجية, واستنتج ان معدل البلى حيث استخدم كل من البوليستر وااليبوكسي للمتراكبة )االيبوكسي+الياف الزجاج( اقل من معدل البلى للمتراكبة )البوليستر +الياف الزجاج( ولجميع المتغيرات من السرع واالحمال المستخدمة. dr.awham,sadeer,bushra(9000) وهما راتنج دراسة البلى االلتصاقي لمادتين بوليمرتين قامو ب االيبوكسي والبولي استر غير المشبع,عند ظروف حمل,زمن وسرعة انزالقية متغيرة لقد اجري اختبار البلى في الهواءوتوصلو بان راتنج االيبوكسي يعاني من معدالت بلى اعلى من راتنج البوليستر غير المشبع بصورة عامة لماء وعند نفس ظروف اختبار البلى الجاف . اظهرت نتائج وكذلك اجري االختبار على عينات اخرى تم غمرها با الغمر بالماء الذي يمثل عامل ملدن للبوليمرات تاثيرا متباينا على سلوك البلى للمادتين في البحث. abdula munium (2011) قام بدراسة تاثير تغيير النسب الحجمية اللياف الكاربون والمضافة الى راتنج %( على معدل البلى االلتصاقي .اجري االختبار تحت ظروف جافة ورطبة 9,6,2كمادة اساس بمقدار) االيبوكسي قرص( واستنتج بان معدل البلى االلتصاقي للعينات المركبة يزداد بعالقة خطية مع زيادة –على -بطريقة )المسمار مع زيادة الكسر الحجمي اللياف الكربون الحمل المسلط والسرعة االنزالقية والزمن االنزالقي ويقل بعالقة خطية .وكذلك بينت النتائج بان معدل البلى االلتصاقي لاليبوكسي المقوى بالياف الكربون عند الضروف الجافة اعلى من معدل البلى عند الضروف الرطبة. البولي استر وبيان الى راتنج %30 ةالياف الزجاج والياف الكربون بنسب كل مناضافة بحثال افي هذوسيتم تاثيرها على مقاومة البلى االتصاقي عند سرع انزالقية متغيرة ومجموعة احمال متغيرة اذ يتم تثبيت حمل معين وزمن ثابت مع تغير السرعة االنزالقية. الجانب العملي : 2 تضمن ما يلي المواد المستخدمة : 2-0 تم استخدام المواد االتية : 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 5 (: وهو احد انواع الراتنجات الحرارية والذي يستخدم بصورة polyester resinراتنج البوليستر الغير مشبع ) -أ واسعة في تصنيع المواد المتراكبة بسبب رخص ثمنه كما انه يوفر تنوع في االستخدامات بشكل واسع,ومن الممكن . (9009,لعيبي) االتعامل مع عمليات التصنيع المختلفة بشكل سهل وبصورة تلقائي industrial chemicals and (icr)والبولستر مادة سائلة ذات لون شفاف مصنع من قبل شركة سعودية هي resins co. ltd. وتم خلط الراتنج كمادة اساس مع المصلب وهو من نوع بيروكسيد اثيل مثيل كيتون بمقدار gr (3 لكل )gr (100) (9002,د. ضياء). وهي الياف صناعية تركيبية غير عضوية, تتميز بمتانة عالية تفوق :( eglass fiberالياف الزجاج ) -ب متانة الصلب واستطالة قليلة ومرونة وكثافة نوعية عاليتين وتتحمل درجات الحرارة العالية اذ تبدأ بفقدان متانتها عند وذات مقاومة عالية لجميع انواع الكيمياويات ولها . co 815وتلين وتنصهر عند درجة حرارة co 315درجة مقاومة عالية للعزل الكهربائي. تستخدم الياف الزجاج في عزل االسالك الكهربائية والعزل الحراري وتستخدم في mm ≥. واستخدمت في البحث الياف جاهزة ومقطعة باطوال (zaid,2006)تقوية البالستك اذ تعطيه متانة اعلى ( الصينية . sinoma jijing fiber glass ppg).co.,ltd ( والتي انتجتها شركة 3) ( : تمتلك متانة وصالدة استثنائية يمكن استخدامها كمواد (carbon fiberالياف الكربون -ج ارات لذلك لها تطبيقات مهمة في هيكلية المواد المركبة وتستخدم خصوصا في صناعة السي (zaid,2006)تقوية وصناعة الفضاء والروبوتات وغيرها بسبب خواصها الميكانيكية الجيدة واستخدمت في هذا البحث الياف كاربون ( يبين الخواص الميكانيكية 1والجدول ) fosroc company والتي انتجتها شركة mm (3)≥جاهزة وباطوال للمواد المستخدمة في البحث . تحضير المواد المركبة: 2-2 حيث تم خلط البولي استر مع (hand layup)حضرت المتراكبات اعتمادا على تقنية التشكيل بالصب اليدوي % 30المصلب ثم اضيفت اليه مواد التقوية وهي الياف الزجاج والياف الكاربون كال على حده وبنسب حجمية المواد في قالب خشبي بأبعاد بطريقة عشوائية وتم الخلط داخل وعاء بالستيكي بصورة تدريجية ثم صب mmطول(100* عرض100*x وذلك بعد تغطية القالب بمادة شمعية لمنع التصاق المصبوبة في 10سمك ) ( في 1القالب وسهولة استخراجها بعدعملية التصلب . وبعدها استخدمت هذه المصبوبات المبينة قي الشكل ) ( وفق 10سمك x 10عرضx 25)طول mmبعاد قياسيه تحضير عينات لغرض اختبار البلى االلتصاقي ذات ا . 2)وكما مبينة في الشكل ) astm g99, 1990))المواصفات العالمية الختبار البلى 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 6 تصنيف العينات : 3 (.2بعد االنتهاء من عملية تحضير العينات صنفت الى مجاميع وكما موضحة في الجدول ) اختبار البلى: – 2 اجري اختبار البلى االلتصاقي للعينات وكما يلي : تم تحضير العينات من تنعيم وصقل للحصول على اسطح مستوية وبذلك تصبح العينات جاهزة لالختبار. -ا ( على قرص الجهازالحديدي 3( الموضح في الشكل ) pin-on-discاستخدام جهاز المسمار على قرص ) -ب . 55hrcذو صالدة اجري االختبار على الجهازوعند المتغيرات التالية : -ج ( وسرعة انزالقية min 5( مع ثبات الوقت )5,10,15,17.5)nحمل متغير وتم اعتماد اربعه احمال هي -0 متغيرة. ( 0( مع كل حمل والذي تم تطبيقه في الفقرة )1.9, 3.75, 5.96) m/secتم اعتماد ثالث سرع هي -9 ( نيوتن ويتم تشغيل الجهاز 5.اذ يتم تثبت الحمل مثال )(min 5) وزمن اختبار ثابت في كال الحالتين وهو مع كل سرعة منتخبة مع هذا الحمل وتكرر العملية مع االحمال االخرى ولثالث سرع . .(9002,د. ضياء) (1حساب معدل البلى من المعادلة ) -9 wr= (1) حيث ان : (w2 -w1) = ( gr ( الفرق بالكتلة قبل وبعد االختبار : ∆w (:2مسافة االنزالق وتحسب من المعادلة ): (2) sd= π d n -حيث ان : n( عدد دورات القرص :r.p.m) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 7 t( زمن االختبار :min) : awham,2010) )(3( من المعادلة ) m/secوتحسب السرعة الخطية لالنزالق ) (3) vs= (π d n)/60 لقياس وزن العينة قبل وبعد االختبار كما gr ) (10-4ذو دقة (ae 160) وقد استخدام ميزان حساس نوع .(4مبين في الشكل ) عالقة بين معدل البلى والسرعة االنزالقية ولكل ( رسمت9ومن النتائج التي تم الحصول عليهاوالمبينة بالجدول رقم ) .(5حمل منتخب والموضحة بالشكل رقم ) : المناقشة -2 ( يظهران ان معدل البلى يزداد مع زيادة الحمل المسلط ولكافة 5( والشكل رقم )9النتائج المبينة في الجدول رقم ) التشوه زيادة يسبب المسلط الحمل بزيادة( ويمكن ان يعزى السبب في ذلك الى انه c1,c2,c3مجاميع المتراكبات ) الحقيقية مساحة التالمس زيادة إلى يؤدي مما النتوءات السطحية قمة عند والحاصل plastic deformationاللدن المسلط الحمل مقدار على بيرك اعتمادا تعتمد) لسطحيه النتوءات ا) التصاق ان عملية اذ المنزلقين السطحين بين ضعيفا يكون السطحية لذلك سوف النتوءات من قمم اعلى عند يحصل فقط االتصال فأن قليل الحمل يكون فعندما سطحي (protective surface film)غشاء بمثابة تعمل االوكسيد من رقيقة تتكون طبقة االنزالق اثناء ألنه االتصال ومنع حصول المنزلقين السطحين بين ما حصول التالمس قلة الى يؤدي مما االنزالق أسطح واق يغطي اقل نتوءات بين ما الحاصلالترابط لقص وفصل المطلوبة القوة تكون سوف وبهذا نتؤات السطحين بين ما المباشر عند ( اما5)في الشكل مبين كما البلى معدل انخفاض ذلك عن وبالتالي ينتج ترابط ذرات المادة نفسها قوة من السطوح خارج تفتيت يحدث اذ هشاشتها وذلك بسبب الطبقة االوكسيدية لغشاء تكسر فيحدث الحمل المسلط زيادة بينها فيما اتصال قوي حصول الى يؤدي مما االنزالق اثناء عملية والقرص العينة من لكلالمتالصقة االنزالقية (metallic junction) نفسها العينة مادة ذرات ترابط قوة من المتصلة أعلى نتوءاتها لقص المطلوبة القوة تجعل فضال عن ارتفاع درجة البلى معدل زيادة الى بالنتيجة مؤدية سطح العينة من دقائق وفصل خلع الى يؤدي مما الحرارة بين السطحين المنزلقين. مابين االحمال)ولجميع المجاميع عالقة ( يوضح ال6فان الشكل ) ولتوضيح تأثير زيادة الحمل بصورة اوضح (.v=1.9 m/secالمستخدمة( مع معدالت البلى وللسرعة االولى ) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 8 لها معدالت بلي c3( نالحظ ايضا ان المتراكبات المقواه بالياف الكاربون والممثلة بالمجموعة 5ومن الشكل ) ويعزى السبب الى ما تمتلكه االلياف c2افضل من المتراكبات المقواه بااللياف الزجاجية والممثلة بالمجموعة الكاربونية من خواص ميكانيكية جيدة ومنها الصالدة التي تعتبر العامل الرئيس بين معدل البلى والمادة وكذلك يبين ان معدالت البلى للمتراكبات المقواة بااللياف الزجاجية والكربونية اقل من متركبات البوليستر الغير مقوى وهي ولجميع االحمال ويعزى السبب الى ان االلياف المقطعة والموزعة بشكل عشوائي بين جزيئات c1 المجموعة البوليستر تؤدي الى زيادة مقاومة المادة الى الخدش والقطع بسبب زيادة الصالدة فتزداد مقاومتها للتشوه اللدن وهذا .يؤدي الى تحسن في خواص البلى اد بزيادة السرعة ولجميع المتراكبات وهذا يعود الى ارتفاع درجة الحرارة والتبريد نالحظ ان معدل البلى يزد وكذلك البطيء مما يؤدي الى نقصان في الصالدة و زيادة في تشوه نتؤات التالمس ونالحظ ايضا ان البولى استر المقوى . بااللياف الكاربونية له معدالت بلى اقل من االنواع االخرى لالسباب الواردة اعاله االستنتاجات : -6 .ولجميع االنواع 17.5nاذ كانت اعلى قيم عند الحمل .يزداد معدل البلى بزيادة الحمل المسلط -أ .ولجميع االنواع m/sec 5.96يزداد معدل البلى بزيادة سرعة االنزالق اذا كانت اعلى قيم عند السرعة -ب % تقريبا باضافة الياف 60مواد التقوية حيث ان معدل البلى ينخفض بمقدار تتحسن خواص البلى باضافة -ج .% تقريبا باضافة الياف الزجاج 40الكاربون و اضافة الياف الكاربون والزجاج للبوليستر يحسن خواص البلى مقارنة مع البوليستر الغير مقوى ولجميع -د .االحمال وسرع االنزالق المصادر : " مجلة مقاومة البلى لخليط بوليمري متصلد حرارياضياء بلقيس محمد و د. عبد الحسين , هدى جبار "د. .0 . 9002, 01, العدد 92الهندسة والتكنولوجيا , المجلة دراسة الخواص الميكانيكية د. صالح , سهام عيسى و د. شبيب , كاضم مطر و د. حمد , قحطان عدنان " .9 2, العدد 92" مجلة الهندسة والتكنلوجيا , المجلة بوليمري مقواة بااللياف والدقائقلمواد متراكبة ذات اساس ,9000. " استخدام التقوية بالياف الكربون لتحسين الخواص لميكانيكية لراتج البوليستر غير سلمان , علي جاهل .9 .9009( , 9( , العدد )95" مجلة التقني , المجلد ) المشبع 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 9 دراسة تاثير البلى في راتج البوليستر غير المشبع المدعم بقشور حامد و يونس , دريد هاني )لعيبي , سعاد .1 .9009( , 9( , العدد)9( مجلة ابن الهيثم للعلوم الصرفة دالة طبقية المجلة ) الرز 5. pihtili, hasim."an experiment investigation of wear of glass-fibre-epoxy resin and glass –fibre polyester resin composite materials" european polymer journal, 45, 2009.ivsl. 6. algbory , abdula munium razoki majaad "composite materials at different working conditions" the iraqi journal for mechanical and material engineering , vol.(11) , no.(3). 2011. 2. m.h.drawham, m.m.,sadeer and h.m.bushra "study of the wear rate of some polymer materials in different conditions ." eng.&tech .journal, vol28,no,16,2010. 2. z.r.m. al-ani, "flexural analysis of composite laminated simply supported rectangular beam". m.sc. thesis, al-mustansiriya university, february (2006). 2. astm, "standard test method for wear testing with a pin-on-disk apparatus/g99", 1990. (zaid,2006) ( الخواص الميكانيكية للمواد المستخدمة في البحث 1جدول ) no الياف الكربون الياف الزجاج بوليستر الخواص kg/m3 1100 2500 1780الكثافة 0 gap 2.8-3.5 72.4 230معامل المرونة 9 gap 0.005 0.008 3.45 4.0اجهاد الشد 9 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 11 ( تصنيف العينات2جدول ) المكونات مجاميع العينات الرموز c1 بوليستر100 المجموعة االولى % c2 الياف الزجاج 30% بوليستر + 70 المجموعة الثانية % c3 الياف الكربون30% بوليستر+ 70 المجموعة الثالثة % ( معدالت البلى للسرع واالحمال المسلطة لجميع انواع المتراكبات3جدول ) الحمل (n) vs (m/sec) wr x10-5 (gr/cm ) c1 c2 c3 5 1.9 2.38 2.22 1.43 3.79 3.68 2.84 1.97 5.69 5.74 3.67 2.45 10 1.9 2.58 2.41 1.57 3.79 4.37 3.16 2.17 5.69 6.95 4.82 3.72 15 1.9 2.75 2.66 1.66 3.79 5.27 3.64 2.51 5.69 7.19 5.32 4.38 17.5 1.9 2.81 2.71 1.74 3.79 6.23 4.72 3.43 5.69 8.65 6.83 5.22 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 11 ( العينات قبل التقطيع1كل )ش ( العينات بعد التقطيع 2شكل ) ( جهاز البلى3شكل ) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 12 حساس ميزان( 2) شكل 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 w r * 1 0 ^ -5 ( g r/ cm ) v m/s c1 c2 c3 n=5 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 13 0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 w r * 1 0 ^ -5 ( g r/ cm ) v m/s c1 c2 c3 n=10 0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 w r * 1 0 ^ -5 ( g r/ cm ) v m/s c1 c2 c3 n=15 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 14 لكل حملومعدل البلى السرعة( العالقة بين 5شكل ) السرعة وثبوت الحمل بتغير البلى ومعدل التقوية مواد بين العالقة( 6) شكل 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 w r * 1 0 ^ -5 ( g r/ cm ) v m/s c1 c2 c3 0 0.5 1 1.5 2 2.5 3 0 5 10 15 20 w r * 1 0 ^ -5 ( g r/ cm ) load n c3 c2 c1 v=1.9 m/s n=17.5 abstract al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 421 self compacting concrete incorporating rice husk ash and metakaolin assistant lecturer abstracte this research deals with the effect of rice husk ash (rha) and metakaolin (mk) as a partial replacement for ordinary portland cement (opc) on properties of self – compacting concrete (scc). three different replacements of rha ( 5% , 10% and 15%) and one replacement of metakaolin (15%) were used for scc. to determine the workability, three test methods were adopted, slump_flow, l.box and v_funnel. the experimental results showed that (rha) improved the strength and modulus of elasticity of scc at age after 60 days . the optimum strength was at 15% replacement . specimens with 15 % replacement of ( mk) showed a better strength and modulus of elasticity at all ages . also the use of( rha and mk) caused reduction in water absorption and increase the ultrasonic pulse velocity. keywords: rice hush ask(rha ), pozzolan; metakaolin(mk), self compacting concrete( scc) لين ؤ والميتاكا لحاوية على رماد قشور الرزا الخرسانة ذاتية الرص جنان جواد حسن علوش جامعة بابل / كلية الهندسة / قسم الهندسة المدنية الخالصة ست كوا) والميتاكواللي رماد قشوور الور تأثيردراسة هذا البحث يتناول دال البورتالنود و السومن مو جو ب % و 41% , 5م رماد قشور الور ) ) استبدال( ثالث نسب .الرص ذاتيةخواص الخرسانة لىع (االعتياد اسوتخدم . اسوتخدم لممول خرسوانة ذاتيوة الورص %(45واحدة م الميتاكاللي ) ) استبدال ( ونسبة % ( 45 والاموو lعلووى شووكل حوور االنسووياب والدووندول فحووص, انة الطريووة للخرسوو التشووليل ليووةطوورل لايوواب قابثووالث .v حر على شكل jinan jawad hassan alwash lecturer babylon university college of engineering e-mail:genan_gwad@yahoo.com al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 425 01تحسو مو مااوموة وممامول مرونوة الخرسوانة ذاتيوة الورص بمود عمور قشوور الور رمواد إ ىإلوالنتائج أشار الحاويووة النموواذ إ %( رموواد قشووور الوور موو و السوومن . 45يووو, , والمااومووة المثلووى كانوو عنوود اسووتبدال ) كوووذل , األعموووارمرونوووة لكافوووة مااوموووة وممامووول أفضووول أظهووور %( ميتاكووواللي مووو و السووومن 45علوووى ) فووول األموووا فووت سوورعة انخفوواف فووت امتدوواص المووا . و يووادة اسووتخدا, رموواد قشووور الوور والميتاكوواللي تسووبب .الدوتية nomenclature ec static modulus of elasticity f fineness modulus ft flexural strength g specific gravity l span length mk metakaolin opc ordinary portland cement p maximum resisted load rha rice husk ash scc self compacting concrete introduction scc was first developed in japan 1980 in order to reach durable concrete structures [campion et al, 2000] . in recent years , a lot of study was done on how to improve the performance of concrete , especially on topics regarding how to increase the strength , durability and flow ability of concrete . scc has been described as ''the most revolutionary development in concrete construction for several decades ' [ colaco et al, 1981] . scc describes a concrete with the ability to compact it self only by means of its own weight without the requirement of vibration . it fills all voids, even in highly reinforced concrete members and flows free of segregation nearly to level balance [ tilo et al, 2002]. due to its specific properties , scc may contribute to significant improvement of the quality of concrete structures and open up new fields for the application of concrete. it can be used in repair applications, hard to reach areas , areas with congested reinforcement such as columns and walls, durable concrete , fair face concrete pumped concrete for long distances besides all other normal concrete applications. scc is different from the conventional concrete in that it has a lower viscosity and , thus , a greater flow rate even when pumped [ celic et al, 2003] scc mixes generally have a much higher content of fine fillers, including cement and produce excessively high compressive strength concrete, which restricts its field of application to special concrete only. to use scc mixes in general concrete construction practice , requires low cost materials to make inexpensive concrete. rice husk is an agro – waste material which is produced in about millions of tons. approximately, 20 kg of rice husk are obtained for l00 kg of rice . rice husk contain organic substances and 20% of inorganic material. (rha) is obtained by the combustion of rice husk . the most important property of rha that determines pozzolanic activity is the amorphous phase content . rha is a highly reactive pozzolanic material for use in lime – pozzolana mixes and for portland cement replacement. rha contains a high amount of silicon dioxide, and its reactivity related to lime depends on a combination of two factors, namely the non -crystalline silica content and its specific surface [akindahunsi and alade , 2010] . al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 420 [ mahmud et al, 2004 ] studied the use of rha to produce high strength concrete and the effect of the addition or replacement of rha compared to silica fume on fresh and hardened mechanical properties .in this investigation ordinary portland cement (opc), rha, silica fume (sf) and sulphonated naphthalene formaldehyde based super plasticizer was used as chemical admixture with varying amounts to maintain workability . the results showed that the addition of rha up to 15% leads to increase the compressive strength , increasing the amount above these values decreases the strength of the concrete . the optimum addition level of rha to produce hsc approximately 10% and the optimum cement replacement with rha is about 5%. [al–abdaly, 2007] studied the effect of the addition of rice husk ash (rha) in two percentages (5, 7.5)% by weight of cement on the mechanical properties and drying shrinkage of high strength concrete . she found that the addition of rha to concrete causing a deficiency by about (16-34) % for compressive strength , (11-16)% for splitting tensile strength , (4-11) % for modulus of elasticity and (7-43) % for drying shrinkage. this reduction was observed for two percentages of rha (5, 7.5)% . metakaolin differs from other supplementary cementitious materials (scms) , such as fly ash , silica fume , and slag , in that it is not a by – product of an industrial process ; it is manufactured for a specific purposes under carefully controlled condition . metakaolin is produced by heating kaolin , one of the most abundant natural clay minerals, to temperatures of (650 -900) c º . this heat treatment or calcination , serves to break down the structure of kaolin . bond hydroxyl ions are removed and resulting disorder among alumina and silica layer yields a highly reactive , amorphous material with pozzolanic and latent hydraulic reactivity , suitable used as partial replacement for portland cement , metakaolin may improve both the mechanical properties and the durability of concrete [bai j and gailivs a , 2009 ] experimental work materials and mixes cement ordinary portland cement (opc) manufactured by united cement company , commercially known (tasluja – bazian) was used throughout this investigation .this cement complied with the iraqi specification no.5:1984 .the chemical composition and physical properties are presented in tables (1) and (2). fine aggregate (sand): kerbala sand brought from al-akhaidher region was used as fine aggregate in the present study .sieve analysis and other properties of this sand are listed in table (3). coarse aggregate (gravel) rounded river gravel from al-nebaee region was used as coarse aggregate in the present work its gradation and other properties are listed in table (4). the maximum size of gravel was 14 mm which preferred for scc [ali 2006] super plasticizer to a chive high workability needed to produce scc, super plasticizer known as flocrete sp33 was used. according to astm c 494-92, this sp is classified as type a and f .the technical description of super-plasticizer is given in table (5). rice husk ash(rha) burning of rice husks according to [habeeb, 2000 and hana, 1984]was carried out in a furnace with controlled temperature in order to establish the optimum burning temperature and burning time. the produced ash was burnt at a temperature of 500 c˚ for two hours. the ash was grounded by los angeles machine ,and to produce finer ash it will be grounded by small mill. the chemical composition of the rha is given in table (6) . al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 421 metakaolin metakaolin is a highly pozzolanic material produced by calcining the clay using an oven at temperature of (750) c˚ for 1 hour.. the particle passing sieve size (0.0015 mm). the chemical composition of metakaolin is shown in table (7). mix design and proportions the japanes mix design procedure (cited by efnarc2002) was followed to design the mix proportion of scc. for the experiments, five series of self compacting concrete were mixed : three different replacement percentages of cement by rha,5%, z10% and 15% : one mix with partial replacement (15%) 0f mk as cement with mix have no (rha or mk) . the mixture proportions are reported in table (8). fresh concrete testing the fresh concrete tests below are specially devised to assess filling ability (flowability), passing ability (passibility) and segregation resistance (stability) of scc. but, there is no unique test so far devised to measure the three properties together. it is important to mention that none of the fresh scc test methods has yet been standardized, and the tests described below are not yet perfected to definitive (efnarc, 2002). these testes are: 1. slump flow test. it is the most commonly used test and gives a good assessment of filling ability. the apparatus is shown in fig (1). at first, the inside of slump cone and the smooth leveled surface of floor on which the slump cone is to be placed were moistened. the slump cone was held down firmly. the cone is then filled with concrete. no tamping is done. any surplus concrete was removed from around the base of the concrete. after this, the cone was raised vertically and the concrete was allowed to flow out freely. the diameter of the concrete in two perpendicular directions was measured. the average of the two measured diameters was calculated. this was the slump flow in mm. the higher the slump flow value, the greater its ability to fill formwork under its own weight. 2. l.box test method. it assesses filling and passing ability of scc. the apparatus is shown in fig (2). the vertical section was filled with concrete, and then gate lifted to let the concrete flow into the horizontal section. when the flow has stopped, the heights (h1) and (h2) were measured. closer to unity value of ratio( h2/h1) indicates better flow of concrete. 3vfunnel test the test measures flowability of concrete. the apparatus is shown in fig (3). at first, the test assembly was set firmly on the ground and the inside surfaces were moistened. the trap door was closed and a bucket was placed underneath. then the apparatus was completely filled with concrete without compacting. after filling the concrete, the trap door was opened and the time for the discharge was recorded. hardened concrete testing. compressive strength. concrete cubes of (150 mm) were used to measure the compressive strength of scc at the ages of (7, 28, 60 and 90) days. this test was performed according to "bs 1881: part 116: 1989" the cubes were moist cured until the age of testing. flexural strength scc prisms of dimensions (100×100×400)mm were cast and tested for flexural strength determination. this test was performed according to "bs 5328: part 4 :1990" specification. the al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 421 concrete prisms were moist cured until the age of testing (28, 60, 90) days. this test was performed using two-point load. flexural strength (ft) is calculated from the following equation: (1...) where: p = maximum resisted load, n. l = span length, mm. b = specimen width, mm. d = specimen depth, mm. modulus of elasticity. concrete cylinder of dimensions (150×300)mm were used to determine modulus of elasticity. this test was performed according to "astm c469-2002" specification . the cylinders were moist cured until the age of testing (28 and 60) days. the test was conducted by subjecting the cylinder to a compression load until failure. two steel proving rings clamped to the cylinder leaving 200 mm gauge length between each other. a dial gauge (0.01 mm/div) accuracy was fixed between the proving rings to measure contraction strain in the concrete cylinders due to the applied compression. the modulus of elasticity ec is calculated using the following equation: (2...) where: ec = static modulus of elasticity, gpa s2 = stress corresponding to 40% of ultimate load, gpa s1 = stress corresponding to a longitudinal strain of 50×10 -6 , gpa 2  = longitudinal strain produced by s2 1  = 50×10 -6 water absorption cube specimens with 100 mm were used for the water absorption test. this test was conducted according to bs. 1881. part 122-1989 after (28 days) of moist curing. these specimens were dried in an oven at (105 ± 5c˚) for (72 hours), then the specimens were immersed in water for (24 hours). the percentage of total absorption was calculated with the following equation: (3...) where: w1 = the average weight of dry specimens (gm). w2 = the average weight of wet specimens (gm). ultrasonic pulse velocity test the upv method can be considered as one of the most promising methods for evaluation concrete structures. this method basically depends on the propagation of high frequency sound wave, which passes through the material by using portable equipment (pundit), composed of the source / detector unit and the surface transducers, which work in the frequency range of 25 to 60 2 bd pl f t    ) ) 12 12     ss ec 100)()((%) absorption 112  www al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 421 khz. the ultrasonic pulses depend on the density and elastic properties of material [lorenzi et al, 2007]. 150 mm cubes were used to measure the propagation velocity of longitudinal stress wave pluses through concrete. the test was performed according to [astm c597, 2002]. pulses of longitudinal stress wave are generated by electro-acoustical transducer that is held in contact with one surface of the concrete under test. after traversing through the concrete, the pulses are received and converted into electrical energy by a second transducer. the pulse velocity is given by the following equation: (4)... t l v  where: v : pulses velocity, (km/sec) l : distance between center of transducer faces, (mm) t : transit time, (µ sec) * all test were conducted in the constructional and materials laboratory in university of babylon . results and discussion a – fresh concrete properties table (9) gives the experimental results obtained from slump flow, l.box and v-funnel tests that were conducted throughout the present work. it can be seen that the test results are within the limits of self-compacting concrete results established in (efnarc 2002). the results of slump flow test show that the flow decreased with increase quantity of rha , by addition of ( 5%) rha the flow decreased by ( 1.26%) , at ( 10%) the flow decreased by ( 4.43%) and at ( 15%) the flow decreased by ( 6.96%). the results of l.box test show that the ratio of l.box decreased with increase quantity of (rha). on the other hand ,it can be seen from table (9) that the mix containing 15% mk showed lower slump value when compared with mix have no (rha and mk) and the amount of reduction was ( 6.32%) . the reason for this behaviour is attributed to increasing of the surface area of the fine materials content which increases the interparticles friction . bhardened concrete properties for compressive strength the specimens were tested at different ages from 7 to 90 days. the results are shown in table (10) and fig (4). according to the results, scc mixes containing rha indicate lower compressive strength until 60 days rather than samples with no replacement, but by increasing the rate of pozzolanic reactions of rha in the matrix, strength of composite mixes goes up. the scc mixes containing 15 % rha have the highest compressive strength among the others. according to [rodriguez, 2006] the rha concrete had higher compressive strength at 91 days in comparison to that of the concrete without rah. the increase in compressive strength of concretes with residual rah may also be justified by the filler (physical) effect. it is concluded that rah can provide a positive effect on the compressive strength of concrete at early ages, besides, in the long term, the compressive strength of rah blended concrete produced by controlled incineration shows better performance. [mahmud et al ,1996 ] reported 15% cement replacement by rha as an optimal level for achieving maximum strength . on the other hand, it can be seen from table (10) and fig (4) that ( 15%) of (mk) by weight of cement enhances compressive strength at all ages . the addition of(mk) into the matrix improves the bond between the cement paste and the aggregate particles as well as increasing the density of the cement paste , which in turn significantly improves the compressive strength of the concrete .according to the literature , the main factors that affect the contribution of (mk) in the strength are athe filling effect , b – the dilution effect and c – the pozzolanic reaction of ( mk) with ch [ wild s et al, 1996 ] . al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 431 for flexural strength the specimens were tested at 28, 60 and 90 days age and test results have been shown in table (11) and fig (5) . in flexural strength like compressive one, mixes containing rha indicate lower flexural strength until 60 days compared to samples with no replacement , at 28 days the flexural strength decreased by ( 3.44% , 6.89 % and 12.06%) when rha was used (5% , 10% and 15%)respectively, and by increasing the rate of pozzolanic reactions of rha in the matrix, strength of the composite mixes goes up. also, the scc mixes containing 15 % rice husk ash have the highest flexural strength in all cases. [habeeb et al, 2009] investigated the effects of concrete incorporating 20 % rah as a partial replacement of cement at three different particle sizes in their study the tensile strength and flexural strength of concrete increased systematically with increasing rah replacement. on the other hand it can be observed in inclusion of (15%mk) as partial replacement of cement cause increase in flexural strength of scc by about (8.6% , 16.9% and 16.5% ) for ages ( 28 , 60 and 90 ) days respectively . table (12) and fig (6) demonstrates the experimental values of modulus of elasticity at 28 and 60 days age for scc of specimens .it can be seen that the influence of ( rha and mk) on the modulus of elasticity is similar to that of strength .the general trend of increasing the compressive strength leading to increase modulus of elasticity [ nevile,1995]. the water absorption at 28 day is shown in table (13) and fig (7) .the results reveal that higher substitution amounts results in lower water absorption values, it occurs due to the fact that (rha and mk) is finer than cement . adding 15% rha to scc, a reduction of (24.2) % in water absorption is observed when compared to mix has no replacement. also adding 15% mk to scc , a reduction of (21.2) % in water absorption when compared to mix has no replacement . table (14) present the values of u.p.v at 28 and 60 days age. it can be seen that inclusion of (rha) as partial replacement of cement enhances the u.p.v of scc. increase in pulse velocity was (1.1%, 2.3% , 3.2 %) at 28 days age and (1.5 %, 2.4 %, 3.3%) at 60 days age for corresponding rha (5 %, 10 % and 15 % ) respectively . as well as the inclusion of ( 15 % mk ) as partial replacement of cement enhances the u.p.v of scc . conclusion 1results indicate pozzolanic reactions of rice husk as in the matrix composite were low in early ages, but by aging the specimens to more than 60 days considerable effect has been seen in strength. 2when ( 15%mk) replaces cement its positive effect on the concrete strength generally start at early ages and also noticeable increase in the strength was observed at later ages . 3the inclusion of (rha and mk) as partial replacement of cement leads to decrease the absorption of self compacting concrete. 4inclusion of (rha and mk) as partial replacement of cement enhances the u.pv of scc. refrences 1. alabdaly , n.m., 2007, " drying shrinkage cracking of high strength concrete", m.sc thesis , university of babylon . 2. ali, esam, m, 2006, "effect of type of filler and water to powder ratio on some mechanical properties of self-compacting concrete", m.sc thesis, babylon university. 3. akindahunsi , a .a and alade .o , june 2010, "exploiting the potentials of rice husk ash as supplement in cement for construction in nigeria ", international journal of concrete structures and materials .vol 4 , no 1. 4. bs. 1881. part 122. 1989, "method for determination of water absorption british standards". al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 434 5. bs 1881: part 117: 1989, "method for determination of compressive strength of concrete cubes", british standards institution, 2 park street. london. 6. bs 1881: part 121: 1983, "method for determination of the static modulus of elasticity in compression", british standards institution, 2 park street, london. 7. bai j . and gailivs a., 2009, " consistency of fly ash and metakaolin concrete ", journal of civil engineering and management , pp.131 – 135. 8. campion m . and jost p., april 2000, " scc: expanding the possibilities of concrete design and placement ", concrete international , no .4, pp. (31-34). 9. celik o . and stephen l., june 2003, "final report; evaluation of self – consolidating concrete ", vtrc o3 –r 13 , virginia , pp( 1-15). 10. colaco j ., ames b . and dubinsky e. 1981," concrete shear walls and soandrel beam moment frame brace new yourk office tower ", concrete international, pp (23-28). 11. efnarc, 2002, "specifications and guidelines for scc", 99 waste 12. street, farnham, feb. (www.efnarc.org). 13. habeeb, g. m., 2000, "residual mechanical properties of high strength concrete subjected to elevated temperatures", ph. d, thesis, university of al-mustansiriyah, college of engineering, november. 14. habeeb, g. a., and fayyadh, m. m. 2009, "rice husk ash concrete: the effect of rha average particle size on mechanical properties and drying shrinkage". australian journal of basic and applied sciences 3(3). 15. hana. a. y., moayad n. k., 1984, "use of rice husk ash in concrete," the international of cement composites and light weight concrete. volume 6. number 4. degussa, chemicals, pp.241-248. 16. " iraqi organization of standards , iqs ' , 5: 1984 , for portland cement . 17. " iraqi organization of standards , iqs ' , 5: 1984 , for aggregate . 18. lorenzi, a., tisbierek, f., and filho, l., 2007, "ultrasonic pulse velocity analysis in concrete specimens", published by: iv conference panamericana de end, brazil. 19. mahmud , h. b , hamid, n.b.a.a., and chia, b.s ,1996, " high strength rice husk asha preliminary investigation, " 20. 3rd asia pacific conferences on structural engineering and construction. 21. mahmud , h. b., koay , y.c.n. hamid , b.a.a., and zain , m.f.m., 2004." use of rice husk ash to produce high strength / high performance concrete ," . national university of malaysia 22. -nevile , a.m.,1995."properties of concrete ," four and final edition , wiley , new york and long man , london . al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 432 23. methe, p. k., 1992, "rice husk asha unique supplementary cementing material, "in: v. m. malhotra (ed). proceedings of the international symposium on advances in concrete tenology. canmet/aci, athens, greece, may. 24. rodriguez, g. s. 2006, "strength development of concrete with rice-husk ash", cement and concrete composites. 28(2). 25. -tilo p . and carl a. 2002, " pressure of formwork and ability to deaerate ", concrete journal , no.17 26. -wild s , khatib jm , jones a, 1996, " relative strength , pozzolanic activity and cement hydration in superplasticized metakaolin concrete ", cement concrete research 26 : 1537 – 1544. table (1): chemical composition of the cement limits of iraqi specification iqs no.5/1984 % by weight oxides -----62.05 cao ----21.36 sio2 ----5.68 al2o3 ----3.52 fe2o3 =5% < 3.25 mgo < = 2.5 if c3a< 5% < = 2.8 if c3a > 5% 2.51 so3 free lime 1.12 ـــــــ ≤ 4% 1.22 l.o.i limits of iraqi specification iqs no.5/1984 % by weight compound composition ---35.36 c3s ---34.56 c2s ---9.1 c3a ---10.71 c4af 0.66 – 1.02 0.86 l.s.f table (2) physical properties of cement limits of iraqi specification iqs no.5/1984 test results physical properties ≥ 2300 3000 fineness,blaine,cm 2 /gm ≥ 00:45 10:00≥ 2:20 3:55 setting time, viecat , s method initial hrs: min final hrs: min ≥ 15:00 23:00 ≥ 19.0 27.0 compressive strength mpa 3days 7days al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 433 table (3):grading and other properties of fine aggregate . limits of iraqi specification iqs no.45/1984 for zone(2) cumulative passing% sieve size 100 100 9.5 mm 90-100 97 4.75 mm 75-100 82 2.36 mm 55-90 71 1.18 mm 35-59 55 0.6 mm 8-30 27 0.3 mm 0-10 4.0 0.15mm limits of iraqi specification iqs no.45/1984. test results physical properties ---2.55 specific gravity g ≤ 0.5% 0.35% sulfate contents as so3 --1.5% absorption 5% ≥ 0.9% fine materials ( passing no 200) ---2.64 fineness modulus fm table ( 4 ) : grading and other properties of coarse aggregate. limits of iraqi specification no.45/1984 cumulative passing % sieve size 100 100 20 90 – 100 100 14 50 – 85 51 10 0 – 10 9 5 2.36 0 ــــ limits of iraqi specification no.45/1984. test results physical properties specific gravity g 2.65 ــــ ≤ 0.1% 0.07 sulfate content as so3 absorption %0.5 ــــ ≤ 3% 0.0% fine materials table (5 ):technical description of the super plasticizer brown liquid color 2c˚ approximate freezing point 1.18kg/l @ 25 c˚ specific gravity less than 2% air entrainment nil chloride content al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 431 table(6 ) : chemical properties of rha l.o.i cl mno so3 mgo na2o k2o fe2o3 al2o3 sio2 cao oxides 3.05 0.53 o.o7 1.7 0.4 1.2 3.3 0.24 0.5 87.5 1.31 percentage table ( 7 ) : chemical composition of metakaolin metakaolin % oxide 69.56 sio2 13.80 al2o3 1.95 fe2o3 2.52 cao 1.2 mgo 0.05 so3 5.1 l.o.i table( 8) : mix design water / powder sp (liter /100 kg cement) mk kg/ m 3 rha kg / m 3 gravel kg / m 3 sand kg/ m 3 cement kg/ m 3 mix designation 0.45 2 0 0 770 750 450 scc( 0% rha) 0.45 2 0 22.5 770 750 427.5 scc(5%rha) 0.45 2 0 45 770 750 405 scc(10%rha) 0.45 2 0 67.5 770 750 328.5 scc(15%rha) 0.45 2 67.5 0 770 750 328.5 scc (15%mk) table ( 9 ) : results of workability tests of scc mixes efnar c scc limits mix designation unit workability test scc(1 5%m k) scc(15 %rha) scc(10 %rha) scc(5 %rh a) scc(0% rha) 600 900 740 735 755 780 790 mm slump fiow 0.8 1 0.92 0.92 0.94 0.97 0.97 h2 / h1)) l . box 6 12 7.5 7.5 7 6.5 6 sec vfunal table (10 ) : results of compressive strength of scc mixes compressive strength mpa mix designation 90 days 60 days 28 days 7 days 52 49 42 29.5 scc ( 0% rha) 54 50 41 27.5 scc ( 5% rha) 55.5 51 40 25.5 scc ( 10% rha) 57 52.5 39 24.0 scc ( 15% rha) 59 55 46 32.0 scc( 15% mk) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 435 table ( 11) : results of flexural strength of scc mixes mix designation flexural strength mpa 28 days 60 days 90 days scc( 0% rha) 5.8 6.5 6.95 scc( 5% rha) 5.6 6.6 7.25 scc( 10% rha) 5.4 6.7 7.45 scc( 15% rha) 5.1 6.8 7.8 scc ( 15% mk) 6.3 7.6 8.1 table (12 ) : modulus of elasticity of scc mixes modulus of elasticity gpa mix designation 60 days 28 days 34.75 33.5 scc ( 0% rha) 34.85 33.3 scc ( 5% rha) 35 33.12 scc ( 10% rha) 35.1 33.0 scc ( 15% rha) 36.2 34.2 scc ( 15%mk) table ( 13 ) : results of water absorption of scc mixes water absorption( %) at 28 days mix designation 3.3 scc(0% rha) 2.9 scc ( 5% rha) 2.7 scc ( 10% rha) 2.5 scc ( 15%rha) 2.6 scc ( 15 % mk) table( 14 ) : results of u.p.v of scc mixes u .p .v ( km / sec) mix designation 60 days 28 days 4.48 4.33 scc ( 0%rha) 4.55 4.38 scc ( 5% rha) 4.59 4.43 scc(10% rha) 4.63 4.47 scc( 15%rha) 4.70 4.49 scc ( 15 % mk) fig ( 5 ):flexural strength development of scc mixes al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 430 fig (1 ) : slump – flow fig( 2) : l – box test vfunnel test fig ( 3): al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 431 20 25 30 35 40 45 50 55 60 0 30 60 90 120 age (days) c o m p re ss iv e st re n gt h ( m p a) scc(0%rha) scc(5%rha) scc(10%rha) scc(15%rha) scc(15%mk) fig ( 5 ):flexural strength development of scc mixes 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 0 30 60 90 120 age (days) fl ex ur al st re ng th (m pa ) scc(0%rha) scc(5% rha) scc(10%rha) scc(15%rha) scc(15%mk) fig ( 4) : compressive strength development of scc mixes al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 431 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 0 30 60 90 age (days) m od ul us o f e la st ic ity (g pa ) scc(0%rha) scc(5%rha) scc(10%rha) scc(15%rha) scc(15%mk) fig(6 ):modulus of elasticity development of scc mixes al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 53 determination of the optimal springback parameters using taguchi method dr aseel hamad abed phd.\uot\department of production engineering and metallurgy, e-mail: aseelhamed2004@yahoo.com abstract bending process is the one important process in the sheet metal forming in many industries, there are many parameters having a large effect on it. springback is considered one of the most important indications to specify the quality of product parts. the objective of the present study is to find the optimum bending parameters to get lowest spring back on aluminumsilicon (alsi) alloy by applying the taguchi method. the basic parameters which were taken into consideration in this work are: punch speed, hold time and the orientation of material in order. experiments have been conducted by using l9 orthogonal array with three levels for each parameter. the bending process were done on instron device ,the optimum combination of process parameters has been found through analysis of main effect of spring back value (αs) and signal-to-noise s/n ratio, and the significant parameter was identified depending on anova analyses. in the present work to determine the level of importance of spring back parameters, the results show that the significant factor is the orientation of metal followed punch speed and hold time, and the obtained results from the experiments are acceptable for the ranges of forming conditions that have been selected in this case study. key word:bending , spring back , optimization, taguchi, anova على الرجوعية باستخدام طريقة تاكوجيالمؤثرة ايجاد العوامل المثلى م.د. اسيل حمد عبد , الجامعة التكنولوجية / قسم هندسة االنتاج والمعادن الملخص لعدجيد من العوامل. تعتبر تعتبر عملية الحني من العمليات التصنعية المهمة في تشكيل الصفائح حيث تتاثر با الؤشرات لتهديد جودة ودقة المنتج. يهدف البحث الحالي الى ايجاد المتغيرات المثلى التي تحقق من اهم الرجوعية بتطبيق طريقة –سليكون عند اجراء عملية الحني الجزاء مصنعة من سبيكة االلمنيوم الرجوعية اقل ما يمكن من هي سرعة التشكيل , زمن التوقف التي اخذت بنظر االعتبار يرات التي تؤثر على الرجوعية. والمتغتاكوجي .اتجاهية المعدنو عملية الحني على . اجريتواقع ثالث مستويات من القيم لكل متغيرب اجريت التجارب باستخدام المصفوفة القياسية s/n) جهاز )االنسترون واوجدت من هذه الدراسة المتغيرات المثالية من خالل تحليل معدل قيم الرجوعية ونسبة mailto:aseelhamed2004@yahoo.com determination of the optimal springback parameters using taguchi method 54 وجد ان التجاهية لتحديد درجة اهمية العوامل المؤثرة على الرجوعية , كذلك باالعتماد على تحليل التباينو حصلة من اجراء التجارب المعدن تاثيرًا كبيرا على العملية يليه سرعة التشكيل ثم زمن التوقف وان النتائج المست ات مقبولة لمدي ظروف التشكيل التي تم اختيارها. introduction bending process are used in various industry branches such as automobile, aerospace, petroleum industries, power systems, spring-back is an unavoidable phenomenon, which accompany the bending process of work parts determined an undesirable change both of bending angle , bending radius, type of material , hold time and the orientation of material . the tools used in bending operations are designed so that they take into consideration the elastic recovery. in order to realize this compensation of elastic recovery measure it is necessary to know the value of the spring-back angle as for back as in the stage of designing the tools. [zeng, 2002] [yanagimoto, 2005] various efforts were made to analyses the spring-back phenomenon analytically, experimentally, and numerically for different shapes, and process and material parameters illustrated in the following research [marciniak, 2002] [dasisva ,2006], [gnatowski, 2008]and [yanagimoto, 2006],w.m. chan and a. nilsson they showed that the spring-back was very much affected by punch speed and die angle [nilsson.a, 1997][chan, 2004]. in bending operation the quality of final form of the part is an important requirement for many bending process? thus, the choice of optimized spring-back parameters is very important for controlling the required product quality [chirita, 2009] therefore, the present work aims to use a statistical experimental design method named “taguchi method” is the method that is presented for this purpose, and it is an effective approach to optimize the setting of the parameters that usually effect on springback in bending process sharing with analysis of variance (anova) and confirmation experiment to verify the objective. 1. taguchi method one method presented in this study is an experimental design process called the taguchi design method. taguchi design, developed by dr. genichi taguchi, is a set of methodologies by which the inherent variability of materials and manufacturing processes has been taken into account at the design stage. the application of this technique had become widespread in many us and european industries after the 1980s. the beauty of taguchi design is that multiple factors can be considered at once. moreover, it seeks nominal design points that are insensitive to variations in production and user environments to improve the yield in manufacturing and the reliability in performance of a product [ghani, 2004]. therefore, not only can controlled factors be considered, but also noise factors. although similar to design of experiment (doe), the taguchi design only conducts the balanced (orthogonal) experimental combinations, which makes the taguchi design even more effective than a fractional factorial design. by using the taguchi techniques, industries are able to greatly reduce product development cycle time for both design and production, therefore reducing costs and increasing profit. moreover, taguchi design allows looking into the variability caused by noise factors, which are usually ignored in the traditional doe approach. [chen, 2001][genichi taguchi, 2001].and also the taguchi approach is a form of doe with special application principles. for most experiments carried out in the industry, the difference between the doe and taguchi approach is in the method of application [thamizhmanii, 2007]. taguchi method is a technique for designing and performing experiments to investigate processes where the output depends on many factors (variables, inputs) without having tediously and uneconomically run of the process using all possible combinations of values. thanks to systematically chosen certain combinations of variables it is possible to separate their individual effects [berginc, 2006]. in taguchi methodology, the desired design is finalized by al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 55 selecting the best performance under given conditions. the tool used in the taguchi method is the orthogonal array (oa). oa is the matrix of numbers arranged in columns and rows [wuy, 2000]. the taguchi method employs a generic signal-to-noise (s/n) ratio to quantify the present variation. these s/n ratios are meant to be used as measures of the effect of noise factors on performance characteristics. s/n ratios take into account both amount of variability in the response data and closeness of the average response to target. there are several s/n ratios available depending on type of characteristics: smaller is better, nominal is best (nb) and larger is better [thamizhmanii, 2007]. therefore, for the present study, “smaller is better” has been depended to find the optimum machining (optimum cutting parameters) which result in a best surface roughness. the signal-noise [s/n] ratio is calculated from applying eq. (1) and eq. (2) [syrcos, 2003] i) for the “smaller is better” quality characteristic, the equation is: ii) the “larger is better” quality characteristic, the equation is: where: s/n is the signal-noise ratio; n the number of observations; and yi the observed data. to achieve the goal of this research “minimum surface roughness (α)”, the smaller (α) value, results in better surface roughness or enhancement the finishing of machined parts. the eq. (1) will therefore be used for that, and yi will represent the surface roughness measurements that will be repeated three times for each experiment 2. experimental worke 3.1 material vdie experimental are conducted on (50* 100) mm (alsi) alloy sheets having thickness of (2 mm). the specimen are cut in three different directions of rolling, normal (0 0 ), perpendicular (90 0 ) and (45 0 ) to the rolling direction these sets will be used for the validation of the vdie bending with different speed (5,50,500)mm / min. and hold time (10, 20, 30) min the chemical composition for aluminum silicon alloy is given in table 1 and the mechanical properties obtained from un-axial tension tests are given in table 2 3.2 vbending experiment a semi closed 90 vdie is designed and used to conduct bending process. the die assembly is installed on the comparison side of 100 kn testing machine (instron machain ) the vdie bending processes are conducted under constant force .the experimental setup for the vdie bending illustrated in figure 1 three experiments are conducted for each rolling directions, punch speed and hold time combination. the bend angles are measured three times on each parameter the resultant spring-back angle for each parameter is obtained by averaging the values of the spring back for t5he three experiments. 3.3 experimental design in order to obtain the representative experimental data, necessary to determine the relative importance of parameters influencing the spring back, based on a minimum number of practical tests, a matrix determination of the optimal springback parameters using taguchi method 56 taguchi l9 (3 3 ) is chosen. the number (9) indicates the number of experiments in different conditions. the number (3) represents the number of the studied parameters, and the number (3) indicates the number of experimentation levels. this kind of experiment is called factorial experiment (3 3 ) because every level of each factor (out of the three) is combined with all the three levels of the other three factors. the experiment using taguchi method was considered. table 3 shows three factors and three levels used in the experiment. if three levels were assigned to each of these factors and a factorial experimental design was employed using each of these values, number of permutations would be (3 3 ). the fractional factorial design reduced the number of experiments to nine. the orthogonal array of l9 type was used and is represented in table 4. this design requires nine experiments with three parameters at three levels of each. the interactions were neglected. 3. results and descution nine different tubes experiments were performed using the design parameter combinations in the specified orthogonal array table. three specimens were fabricated for each of the parameter combinations. the completed response table for these data appears in table 5. the signal-tonoise ratio (s/n) should be as smaller as possible, because the quality characteristic “smaller is better” was used. s/n values were calculated from eq.(1), and the results have been arranged in the last column of array in table (5). the results were analyzed by using main effects for both springback values and signal-to-noise ratio (s/n), and anova analyses. then the estimated results which obtained checked experimentally to insure the estimate value. in terms of the average effects, the average value of spring back and (s/n) ratio for each parameter (a, b, an c) at each level (level 1, level 2, and level 3) were obtained and the results are summarized in table 6. the graph that shows the main effects for spring back can be represented as shown in figure 2, 3, 4 depending on data in table 5 and table 6. because of using “smaller is better” quality characteristic in this study, the smaller average of spring back that appears in figure 2 represents the smaller value of spring back, so the combination of parameters and their levels a3b2c3 (rolling (0) direction degree, punch speed (500 mm/min), and hold time (30 min.) represents the optimum condition. the difference (max-min) of three levels for each parameter indicates that the punch speed has the highest effect on the spring back followed by rolling direction and hold time. 4. anova (analysis of variance) the relative influence of the three factors on the spring back is determined by the anova method (analysis of variance technique). the method is based on the idea of separating the variance in several component parts in order to determine which of the experimental factors have an influence on the dependent variable, namely on the spring back. therefore the purpose of the analysis of variance is to investigate which factors significantly affect quality characteristics [sang, 2006]. the percent contribution of each parameter is evaluated to make a decision on how significant the effect of each parameter. anova table for the spring back test is organized as shown in table 7. 5. conclusion this research gives how to use taguchi’s parameter design to obtain optimum condition withlowest spring back, minimum number of experiments and industrial engineers can use this method.  the combination of conditions and their levels ( a3b3c3 )(punch speed 500 m/min, rolling direction (90) o and hold time 30 min) are recommended to order to obtain a lowest spring back for vdie bending aluminum sheet .  the experimental conducted with taguchi method and from the analysis of variance al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 57 (anova) in table 7 has demonstrated that the punch speed is larger effect on spring back then rolling direction and hold time.  taguchi gives systematic simple approach and efficient method for the optimum parameters. references ( berginc b., z. kampus, b. sustarsic,2006) “the use of the taguchi approach to determine the influence of injection-moulding parameters on the properties of green parts”, journal of achievements in materials and manufacturing engineering, 15,pp. 63-70. ( chan w.m , h.i. chew, h.p. lee, b.t. cheok,2004) finite element analysis of spring-back of v bending sheet metal forming processes”, journal of materials processing technology 148, pp.15-24. (chen, j. l.,2001) “a systematic approach for identifying optimum surface roughness performance in end-milling operations”. journal of industrial technology, 17 (2). (chirita bogdan alexandru,2009) “ method of optimization of sheet metal forming processes concerning the reduction of spring back” the annals of “dunarea de jos” university of galatif asciclev , technology in machine building, issn pp.12214566. ( dasisva botelho .t, e. bayraktar, g. inglebert,2006) “comparison of experimental and simulation results of 2d-draw-bend spring-back”, journal of achievements in materials and manufacturing engineering, 18, pp. 275-278 . (genichi taguchi,2001) “taguchi method “ new york: wiley. ( ghani .j.a, i.a. choudhury, h.h. hassan,2004) “application of taguchi method in the optimization of end milling”, j. mater. process. tech. 145 (1),pp. 84–92 . ( gnatowski .a, p. palutkiewicz, e. bociga, 2008)” numerical analysis of stress state during single point bending in dmta examinations”, journal of achievements in materials and manufacturing engineering 28/1, pp.47-50. ( marciniak .z, j.l. duncan, s.j. hu, 2002) “mechanics of sheet metal forming) , second edition, butterworth-heinemann press. ( nilsson.a, l. melin, c. magnusson,1997) ” finite-element simulation of vdie bending: a comparison with experimental results”, journal of materials processing technology 65 , pp.52-58. ( sang-heon lim, c.-m. l.,2006) “a study on the optimal cutting condition of a high speed feeding type laser cutting machine by using taguchi method”. international journal of precision engineering and manufacturing, 7 (1). ( syrcos. g.p,2003) die casting process optimization using taguchi methods, journal of materials processing technology 135 , 68-74. determination of the optimal springback parameters using taguchi method 58 (thamizhmanii .s,2007) “analysis of surface roughness by turning process using taguchi method” journal of achievement in materials and manufacturing engineering, vol. 20 , 1-2, pp. 503–506 . (yanagimoto, j. and oyamada, k.,2005) ” spring-back of high strength steel after hot and w arm sheet forming”, annals of the cirp, 54 (1),pp. 213-216 . (yanagimoto,j.oyamada,2006) “ spring back free isothermal forming of highstrength stress sheets and aluminum alloy sheets under worm and hot forming condition” int. 46,pp.1324-1328 . ( wuy, a. wu, 2000) “taguchi methods for robust design”, asme, new york. (zeng, y., li, z.,2002) “experimental research on the tube push-bending process.” journal of materials processing technology 122, pp. 237-240. table 1 the chemical composition for (alsi) alloy al mn pb ni cr zn mg cu fe si element 99.2 0.004 0.006 0.012 0.004 0.019 0.0043 0.01 0.19 0.6 % table 2 the mechanical properties of aluminum alloy in different directions. property 0 degrees 45 degrees 90 degrees young’s modulus 69 gpa 69 gpa 69 gpa yield strength 118 mpa 130 mpa 137 mpa ultimate tensile strength 131 mpa 142 mpa 143 mpa % elongation 6.2 % 3.8% 4.5% table 3 level of process parameters level symbol factor 1 2 3 a rolling direction in degree 0 45 90 b punch speed (mm/min) 5 50 500 c hold time (min.) 10 20 30 table 4 the taguchi l9 orthogonal array standard order a b c rolling direction degree punch speed (mm/min) hold time (min.) 1 0 5 10 2 0 50 20 3 0 500 30 4 45 5 20 5 45 50 30 6 45 500 10 7 90 5 30 8 90 50 10 9 90 500 20 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 59 table 5 bending conditions of experiments, spring back and s/n results experiment number experiment condition individual spring back measured for each experiment degree springback average degree s/n a b c rolling direction punch speed hold time n1 n2 n3 1 0 5 10 6.3 6 6.3 6.2 -15.85 2 0 50 20 4.9 5.3 4.8 5 -13.98 3 0 500 30 4 3.3 3.2 3.5 -10.93 4 45 5 20 6 5.3 5.2 5.5 -14.85 5 45 50 30 3.9 4.3 3.8 4 -12 6 45 500 10 3.2 2.9 3.2 3.1 -9.83 7 90 5 30 3.4 4 3.9 3.8 -11.54 8 90 50 10 4.2 3.3 3 3.5 -11 9 90 500 20 2.2 2.3 2.5 2.3 -7.4 table 6 main effect table for spring back symbol spring back parameters average of spring back max-min level1 level2 level3 a rolling direction degree 4.9 4.2 3.5 * 1.4 b punch speed (mm/min) 5.21 4.16 3 * 2.21 c hold time (min.) 4.3 4.26 3.76 * 0.583 table 7 anova table for the spring back symbol sum of squares degrees of freedom mean squares a 11.94 2 5097 b 16.561 2 8.281 c 5.296 2 2.648 total 33.797 6 determination of the optimal springback parameters using taguchi method 60 figure 1 the experimental setup for the v-die bending figure 2 main effects graph for spring back with rolling direction al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 61 figure 3 main effects graph for spring back with punch speed figure 4 main effects graph for spring back with hold time. عنوان البحث:اثر المعتقدات الدينية في تشكيل الفضاءات الحضرية في مدينة بابل 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 التاريخية لمدينة الكفلوضوحية البيئة الحضرية م الفضائيينظتلتغيرالخصائص التركيبية ل اثرحول دراسة تحليلية) الكفل دينةفي م مواقع الدالةالبوضوحية الصورة الذهنية وتحديد ( التاريخية / مدرس مساعد أميرة جليل احمد ة بابلجامع/قسم الهندسة المعمارية/ كلية الهندسة ameera_jaleel@yahoo.com ملخصال وفي محاولة اليجاد نوع ،موضوع وضوحية البيئة الحضرية تناولت دراسات وبحوث عديدة ضوحية الصورة الذهنية بو لنظام الفضائي التركيبية ل خصائصتغييرال العالقة التي تربط بين للمدن في االونة االخيرة يز التخطيطتم حيث وتحديد مواقع النقاط الدالة في المدينة، للمتلقي ومن خالل استقراء . عدم االستناد الى االسس العلمية التاريخية في العراق بالعشوائية و عدم وجود تصور معرفي يوضح مدى عالقة ) -:مشكلة البحث الدرااسات السابقة تم تحديد واستنادا . (رية للمتلقيتغييرالخصائص التركيبية للنظام الفضائي بوضوحية البيئة الحض من -:)منهج بنوي -اعتمدت منهجين علميين تحليلين االول:لفرضيات البحث ولتحقيق أهدافه ( في تحديد اوزانا رقمية للهيكل الفضائي تعبر space syntaxخالل استخدام الطريقة الحسابية) من خالل اعداد -:ادراكيمنهج هذه االوزان عن قوة العالقات النسبية الجزاء الهيكل. والثاني الصورة الذهنية للمتلقي والنانجة عن اختالف درجات وضوحية على استمارات استبيان للتعرف بما يالئم أفكار و معالجة مشكلة البحث لو ، (البيئة الحضرية وتحديد مواقع النقاط الدالة في المدينة ثية الاهمية هذه المدينة التاريخية تم انتخاب مدينة الكفل التاريخية كعينة بح وأهداف البحث ، ومن ثم الوصول لمجموعة من االستنتاجات ولمعاناتها من االهمال لفترات طويلة من الزمن والتوصيات. )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 ، االدراكية ، (environment urban)البيئة الحضرية ، (legibility)الوضوحية :الكلمات الدالة درجة ، (space syntax)التركيب الفضائي ، ( significant positions) الموقع الدالة ، البنيوية (integration)التكامل legibility of al-kifl historical city environment urban ameera jaleel ahmad babylon university college of engineering assist lecturer in architecture engineering department architecture engineering ameera_jaleel@yahoo.com abstract this study is mainly concerned with legibility in urban environment in an attempt to find the kind of the relationship between changing the structural propertires for the space discipline in legibility of the mind picture for the witness and indicating the significant. lastly, planning for historical cities in iraq is aimlessly done and it lacks the scientific fundamentals. the problem of the study is that there is no cognitive vision which clarifies the relation between changing the structural properties for the space discipline in legibility in urban environment receiver according to the hypotheses of the research and to achieve its aim, the researcher was adopted two scientific ways: the first one the structural methodthrough using of arithmetical way in indicating numerical weighs for space structure .the weighs express the relative for the structural parts. the second one: the perceptional method: by using questionnaire to know the mind picture for the receiver which results from the difference of the legibility degree in urban environment and indicating the place of indicator points in the city. for the purpose of the research and to achieve and treat the research problem in accordance with the aims of the research , the researcher, chose al-kefil city as a historical city as a sample of the study for its importance from the historical point of view to reach up some conclusions and recommendations. مقدمةال علمية وخصوصا في سس ا وعدم االستناد الى بالعشوائية للمدن العراقية تميز التخطيط في االونة االخيرة. ش لفترات طويلةوالتهميالمدن التاريخية التي افتقر الكثير منها للتوثيق والتواصل نظم االتصال الحضرية باعتبارها للبيئةبالخصائص التركيبية كثيرة دراسات اهتمت واسع وهومفهوم الحضريةلبيئة احد مقاييس امفهوم الوضوحية يعتبر واالجتماعي والحضاري ، التصميم الحضري والمعماري ، ريالحض التخطيطمنها )معرفية متعددة ومرتبط بميادين ومتنوع .(علم النفس والسلوك، mailto:ameera_jaleel@yahoo.com mailto:ameera_jaleel@yahoo.com 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 يرى البحث إن مفهوم الوضوحية مفهوم واسع وشامل ويعتبر صفة لقياس نوعية البيئة الحضرية (urban environment quality يتداخل مع تركيب المدينة ليمثل سهولة استيعاب البيئة ) يعنى البحث.الشموليالمستوى شترك على وتجميع أجزائها وعناصرها في نظام موحد ونسق م قع المواضع الدالة وخصائصاو مبين )الجانب الذاتي( بدراسة إشكالية طبيعة العالقة التصورية وضوحية في دراسة ويمثل البحث محاولة اولى من نوعها ()الجانب الموضوعيالتنظيم الفضائي لى مؤشرات تخطيطية تساهم في تطوير بغية الوصول امدينة الكفل التاريخية البيئة الحضرية ل ليتيح المجال للباحثين لدراسة وتغطية الفجوات المعرفية في مجاالتها المختلفة. و هذه المدينة. مفهوم البيئة الحضرية مفهوم البيئة الحضرية واسع ويشمل العالم المحيط بنا حاويًا كل شئ نراه أو نشعره به أينما ) كونه سلسلة من التراكيب المادية أن نراه، فهو يرتبط معنا مكانياً كنا وحتى ما ال نستطيع كونه استمرارية لقيمتها االجتماعية والثقافية والدينية عبر مجموعة من ) وزمانياً والفعاليات( . (المتغيرات التي تنشا وتتبلور وقد يعاد تشكيلها وتطورها ,rapoprot)ومنها دراسة إلى مركبات الدراسات التي صنفت البيئةومن خالل االطالع على أن البيئة استنتجنا ( broadbent,1973) ،ودراسة (lynch1984)،ودراسة (1977 تتكون من جانبين أساسين، األول يتعلق باإلنسان كفعل صادر منه أو كرد فعل ناتج من تفاعله والتي بدورها تتكون ( build environment) مع الجزء الثاني للبيئة والمتمثل بالبيئة المبنية أما (objects)من جزأين أساسين يمثل أحدهم البيئة الفزياوية وهي اإلمكانات الموضوعية للبيئة األخر فيتمثل بالفضاءات وتنظيمها كونها األثير الرابط لعملية التفاعل بين اإلنسان والبيئة حث أن مفهوم وضوحية البيئة الفزياوية والذي يحدد ماهية البيئة الحضرية.وهكذا يجد الب الحضرية تتحدد من خالل االتصال والتأثير المتبادل بين اإلنسان وكل ما يتعلق به من متغيرات وثوابت وسلوك إنساني متضمن العادات والتقاليد الثقافية والحضارية والفعاليات واألنشطة وبين كتل بنائية وتنظيم فضائيعن البيئة المبنية التي هي عبارة مفهوم وضوحية البيئة الحضرية تاريخ ظهور تبحث هذه الفقرة في طبيعة نشوء فكر الحداثة ونشؤه والمشاكل المرافقة له مع اإلشارة إلى بداية ظهور الوضوحية والتوجيه كإشكالية في تخطيط المدينة. إن التغيرات والثورات الفكرية والعلمية لى تغير النتاج المعماري كونه العاكس الرئيسي لحياة التي قد تحصل في حقبة زمنية ما تؤدي إ وهذا ما حدث مع الحركة الحديثة فقد اقتبست العمارة الحديثة ( (bonta, 1979 المجتمع )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 ,curtisأهميتها من كونها مثلت نزعة جديدة في المجتمع آنذاك استهدف خلق مجتمع ديمقراطي ثورة معمارية كنتيجة للتطورات الفكرية و ما رافقها من في بداية القرن العشرين حدثت ( (1982 . ة والسياسية التحوالت االجتماعية واالقتصادي وقد كان ، (1960وقد الحظ العديد من المخططين أن التوجيه في المدينة أصبح شيئا صعبا القدرة عدم وضوح التمثيل الذهني في المدينة الحديثة أحد ابرز نقاط ضعفها. فقد أصبح عدم على التمييز بين أجزاء المدينة ميزة أساسية في المدن المنشأة بناءا على نظرية الحداثة (schultz, 1971) كما اختلف مبدأ التكوين في المدينة عن المبدأ التجميعي كما كان في المدن . (lynch, 1960)التقليدية وأصبح يتوجه نحو مبدأ اإلقصاء والذي ينقل رسالة إلى العالم المفتوح ( فلقد شهد post modernismأما بالنسبة إلى موقف الحضريين في فكر ما بعد الحداثة ) توجها جديدا نحو العمارة والتخطيط وقد ابتدأ ذلك في الواليات المتحدة األمريكية ومن ثم انتشر تخطيط إن مشكلة ال ويستنتج البحث مما تقدم .( (ghirardo, 1996إلى باقي الدول الصناعية العراقية هي تمسك الدوائر التخطيطية ولغاية اآلن بأفكار النظرية الحديثة مما خلق في المدن في مما يؤدي إلى الكثير من المشاكل . وضوحية ال ضعيفةبيئات حضرية التاريخيةالمدن .الضعيفةوالخسائر االقتصادية التي قد تظهر في المدن ذات الوضوحية كية والتركيبيةااالدر الطروحاتمن خالل حيةتعريف مفهوم الوضو العديد من المجاالت العلمية كعلم النفس والجغرافيا بلبيئة الحضرية ايدخل مفهوم وضوحية في المناطق ف والعمارة فضال عن التخطيط الحضري لما له من أهمية وتأثير ذي مدى واسع، رتب عليها مجموعة عمليات البحث يشعرون بنوع من اإلشكالية يتالنسان ا التي ال يعرفها واالستقصاء وحتى طلب المساعدة من اجل الوصول إلى الوجهة التي يطلبونها وعندما يصلون إلى تلك الوجهة، يتالشى ذلك اإلحساس باإلشكالية. ولقد تناولت العديد من الدراسات مفهوم -ومنها: الوضوحية والمفاهيم المرتبطة به ((remco chang, 2007 دراسة،( (lynch, 1981دراسة ، (lynch, 1960))دراسة ، دراسة ((hillier, 1984، ودراسة ((bentley, 1985، ودراسة (1002)كمونة،،ودراسة ( hillier, 1996)، ودراسة(thierry r. 1998) ، ي عمليات ان البيئة الواقعية تمتلك التأثير الملحوظ. والبيئة الواضحة تمتلك قيم واضحة فتبين اإلدراك الحسي و المعرفي كما أنها تكون مصدرا لألمان العاطفي وأساسًا قويًا لإلحساس بالهوية الفردية ) اإلحساس بالذات ( وارتباطنا بالمجتمع. حيث تعمل الوضوحية في البيئة الحضرية بدعم 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 مات الفردية عن اإلحساس بالفخر بالمواطنة والتماسك االجتماعي. وتصبح وسيلة لتطوير المعلو العالم الخارجي. لوضوحية أبعادًا عديدة يتعدى سهولة الذهاب إلى موقع العمل صباحا والرجوع إلى المنزل ول فالمفهوم له أبعاد اجتماعية وثقافية وحضارية واقتصادية. إن مفهوم الوضوحية مصطلح واسع يجاد الطريق (orientation)وشمولي وقد يضم العديد من العمليات والمراحل منها التوجيه وا (way finding) . ننا في الحالتين نحتاج إلى وسائل وأدوات للمساعدة من اجل الوصول إلى و ا hidden and visual)وجهتنا. وتتمثل هذه الوسائل بالهيئات المخفية والمرئية للبيئة الحضرية features in the unban environment) حيث إن هذه الهيئات البصرية (visual features) أو النقاط المرجعية(reference points) أو المواضع الدالة(significant & positions )تمثل إلماحات بيئية تستخدم من اجل تأكيد صحة المعلومات البيئة التي تعرف فهي (hidden features)أما الهيئات المخفية ( identify the placeالمكان ) خصوصية الفضائية ذات التأثير الضمني والتي تستخدم غالبًا من قبل اإلنسان من دون رد البيئة وهي التي تجعل الناس والمركبات يتدفقون وينتشرون خالل (reflection or reactionفعل) المدينة. كال من الهيئات المخفية والبصرية تؤثر في وضوحية البيئة الحضرية. مفاهيم الوضوحية وهو مفهوم معقد في بعض الحاالت فقد إن انتظام المخطط هو أحد تكون هذه المنظومة محيرة ما لم تكن مرتبطة بنوع من االختالفات. فقد اقترح بعض علماء يجاد النفس نظام للتصنيف البيئي الهدف منه زيادة وضوحية البيئة واحتماليه التوجيه الفضائي وا درجة االختالف ودرجة في االعتبار في دراستهم هي أخذت ثالثة مقاييسالطريق معتمد على . المفاهيم ارتبطت بالطريقة التي توضحها الوصولية الحضرية ودرجة تعقيد المخطط الفضائي (2المصفوفة في الشكل رقم) والتي هي نموذج مصغر لتقيم وضوحية البيئة الحضرية، توضح المصفوفة أن درجة منخفضة ة بصرية منخفضة في مخطط معقد سوف تؤدي إلى مشاكل من االختالف مع درجة وصولي عالية جدًا في الوضوحية والتوجيه الفضائي. ومن جهة أخرى فاالختالف العالي مرتبط بوصولية دراسة البصرية جيدة ومخطط بسيط يعطي أفضل الظروف بالنسبة إلى التوجيه الفضائي. وتعرف اء من البيئة متشابهة أو مختلفة أثناء تأثيرها على االختالف على انه الدرجة التي تبدو فيها أجز قدرة الناس في تمييز أالماكن، وهذا سوف يؤثر في كل من الزوار الجدد والمستخدمين الساكنين األكثر خبرة بالنسبة إلى قدرتهم على التوجيه الفضائي أو إيجاد الطريق في البيئة المحددة.بالنسبة الحجم / الشكل / اللون / والطراز –اسة متغيرات مثل إلى خصائص االختالف ذكرت الدر .( (garling tonny, 1986 .اختالف الوظيفة. كما أخذت بنظر االعتبار المعماري )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 و الغموض والتنوع مفهوم التعقيد االهتمام بالتعقيد ووفرة المعلومات المتقاطعة ومقدار غموضها وتنوعها يرتكز على العالقة بين فالهدف من اإلدراك المعرفي (cognition)واإلدراك المعرفي(perception)الحسي. اإلدراك إلى مجموعة من المواضع (representation)هو في فهم البيئة عن طريق تبسيطها وتمثيلها الدالة التي تعرف أجزاء البيئة ككل وربطها في منظومة تمثل مخططات وخرائط ذهنية. ومن ر اإلدراكي الحسي يتم من خالل اإلحساس بالخصائص الشكلية جهة أخرى فان االختبا دراك هاوالفيزيائية للبيئة فبينما يريد الناس أن يكونوا قادرين على فهم المدينة بوضوح وا (rapoprot, 1977) باستخدام خرائطهم الذهنية فهم يحتاجون إلى نظام غني بالمعلومات عن عن طريق إضفاء نوع من التعقيد والتنوع إلى المعلومات هذه المدينة واإلحساس بنوع من التغير البيئية بداًل من الرتابة والملل. والذي يتم عن طريق االتصال واالنقطاع عن اإلحساس بالنظام الشمولي للمدينة من خالل خلق نوع من التعقيد باختالف وسائله. الحضرية من دون الحدود التي لذلك فان التعقيد يقترح مستويات من الفرص الستخدام البيئة تجعل منها غير مرغوبة حيث أن درجات معينة من التعقيد على المستوى الموضعي تمنح شعورًا معتدال وتمنع اإلحساس بالملل واإلحباط غير المحبذين. هنالك طريقان لتحقيق التعقيد هما التنوع والغموض فالتنوع يرتبط بتنظيم العناصر واالختالفات ة بينها فيما يتعلق باإلدراك الحسي بشكل عام فهو يهتم بالتغيرات واالختالفات بين القائم . أما الغموض فهناك وسيلتان (rapoprot, 1977)المنبهات أكثر من كونه تغير في المنبه لتحقيقه األولى تتعلق بعدم التأكد من الشكل وهو شئ يتعلق باإلدراك الحسي ويمكن السيطرة يمكن رؤية أو إدراك الفضاء أو الشكل )المنبه( من مكان أو نقطة نظر واحدة عليه حينما ال فهناك عدم تأكد من الشكل ويحتاج إلى أكثر من زاوية نظرة إلدراكه حسيًا لكون الشكل أكثر الوسيلة الثانية متعلقة بتعددية المعنى للشكل (rapoprot, 1977)تعقيدًا من الشكل البسيط بالنواحي األدبية وبالتالي فهو متداٍع. وبما انه متداٍع ورمزي فهو يرتبط الواحد وهو متعلق بالنواحي الثقافية ويمتلك خصوصية عالية يصعب على المخططين التحكم بها. العوامل المؤثرة في مفهوم الوضوحية في وضوحية البيئة الحضرية والتي ترجع إلى مكونات هناك مجموعة من العوامل التي تؤثر بيئة الحضرية نفسها والتي تتضمن اإلنسان والبيئة المبنية المكونة من الشكل المبني والفضاء ال وان لكل من هذه المكونات خصائص تؤثر بشكل أو بأخر في مفهوم الوضوحية، فمن جانب اإلنسان فانه باختالف جنسه وعمره ومستواه االجتماعي واالقتصادي والحضاري، يؤثر فيما 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 ه االدراكية ونضوجها وقدرتها على التفاعل مع المؤثرات والمعلومات الخارجية أو ما يتعلق بأجهزت يتعلق في نظام حركته اليومية وفعالياته ومتطلباته ودوافعه أو ما في عاداته وتقاليده وكل ما يتعلق باألبعاد الدينية والحضارية والثقافية فضال عن خبرته السابقة. إن كل واحد من هذه رات يؤثر في الوضوحية من خالل تأثيرها على المنظومة االدراكية لإلنسان في تعامله مع المتغي البيئة الخارجية وفي كيفية صيانته وتمثيله لتلك البيئة في ذاكرته، وبذلك فان كل متغير متعلق باإلنسان الذي يمثل بالجانب األول من البيئة الحضرية يؤثر في قدرته على اختيار المواضع دالة التي تعرف له أجزاء البيئة الحضرية. وبالتالي بنية المخططات الذهنية.ال والتي ( build environment) أما الجانب الثاني في البيئة الحضرية فهي البيئة المبنية فتأثيرها في وضوحية البيئة ( space) والفضاءات ( build form) تتكون من الشكل المبني ) خصائصها تمثل المعلومات البيئية التي يتم عرضها وبشكل متدفق الحضرية يختلف الن information flow ) على اإلنسان خالل حركته في البيئة وتقسم هذه الخصائص إلى الخصائص التي تؤثر على جهازه اإلدراكي الحسي حيث تتنافس المعلومات الحضرية فيما بينها لك الخصائص األكثر تميزًا واختالفًا وتأثيرا على لتميز الموضع الدال وهو العنصر الذي يمت اإلنسان مقارنة بما يحيطه من البيئة الحضرية، ليقوم بدوره الخاص بتعريف أجزاء البيئة الحضرية أما الجانب األخر فتتمثل بخصائص العالقات الفضائية ألهميتها فيما يتعلق بالحركة ضعية للفضاء وعالقته بالمنظومة الشمولية الحضرية ويكون تأثيرها من خالل الخصائص المو للبيئة المبنية وتمثل هذه الخصائص الفيزياوية الفرص المتاحة في البيئة التي تحدد أنماط الحركة وخياراتها. وبذلك فهي تؤثر في وضوحية البيئة الحضرية بشكل غير محسوس لكن يمكن حسابها. مفهاااااااااوم اضاااااااااع الدالاااااااااة بالدرساااااااااات الساااااااااابقة التاااااااااي تناولااااااااات عالقاااااااااة المو وضوحية البيئة الحضرية بعد أن تم تناول مفهوم الوضوحية في البيئة الحضرية والمفاهيم المرتبة عليها ومناقشة عالقة الوضوحية بمكونات وخصائص البيئة الحضرية والتي أثبتت أن الوضوحية ناتجة من تفاعل ية وقد وجهت الكثير من الدراسات مكونات البيئة الحضرية أي بين اإلنسان والبيئة المبن والنظريات المختلفة التي تناولت موضوع البيئة الحضرية اهتمامها نحو وصف وتفسير كيفية استخدام البشر لمخططات البيئة أثناء قيامهم بأداء فعالياتهم المختلفة وذلك عن طريق دراسة )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 34 لموضوع بين الدراسات فقد ظهرت السلوك البشري في أنماط مختلفة من البيئة وبالرغم من توحد ا مفاهيم ونظريات متعددة اختلفت عن بعضها بشكل كبير وتعزى هذا االختالفات بين المفاهيم والنظريات إلى اختالف الحقول العلمية التي ظهرت من خاللها أو تأثرت بها تلك الدراسات وع البحث وهو وضوحية استعراض الدراسات بالنسبة إلى ارتباطها بموض هذه الفقرةونحاول في البيئة الحضرية. ولغرض تنظيم مناقشة األفكار والنظريات المختلفة فقد تم تصنيفها بالشكل آالتي: وتشمل مجموعة الدراسات التي تستند على خصائص السلوك النظريات والدراسات السلوكية: كالنظرية الحيزية ودراسات الفضائي كمنطلق للبحث في العالقة بين اإلنسان وبين البيئة المبنية، إن توجه النظرية الحيزية يفسر عالقة اإلنسان بالمكان بواسطة دوافعه علم النفس االيكولوجي. بايولوجية فقط، وان اإلنسان يتعرف إلى المكان بشكل واضح من خالل غرائزه فضال عن كونها ذ كيف تفسر عامل متغير ال تستطيع أن تفسير االختالفات األساسية في التنظيم الفضائي، إ بعامل ثابت. أما بالنسبة إلى دراسات علم النفس االيكولوجي فإنها تفسر تعرف اإلنسان على المكان ووضوحيته عن طريق سهولة الوصول العالية وامتداد المحاور البصرية إلى أماكن التي ع معايير يمكن يسهل الوصول إليها من قبل اكبر عدد من األشخاص. أي أن الدراسة لم تض على أساسها تعريف المكان إال بعد تجربته واكتشاف مناطق مراكز السلوك إن كل من الدراستين لم تعرف طريقة ربط اإلنسان بأجزاء البيئة الحضرية وتحديد موقعها ضمن المنظومة الشمولية والشمولي أي أنها لم تعرف طبيعة العالقة بشكل دقيق وقابل للقياس بين المستوى الموضعي للمكان. وعليه ال يمكن االعتماد على هذه التوجهات في دراسة مفهوم الوضوحية. وتشمل مجموعة الدراسات التي تستند إلى تحليل الجهاز اإلدراكي النظريات والدراسات االدراكية: ل لإلنسان والمتغيرات الرابطة الكامنة في ذهنه كمنطلق للبحث في العالقة بين الوضوحية في ك من طرفي البيئة الحضرية اإلنسان والبيئة المبنية. مكانية تعريفه لموقعه بالنسبة إلى تستند الدراسات االدراكية في تفسير العالقة بين اإلنسان وا المنظومة الشمولية من خالل إمكانياته االدراكية والعمليات األساسية للتحسس واإلدراك حيث تفكير الذهني البشري وعلى رد الفعل المباشر للبيئة على تركز هذه الدراسات على طريقة ال اإلنسان وكيفية تعامله مع خصائصها وتعلم استخدام البيئة في حياته اليومية حيث أن سلوك اإلنسان في الفضاء يعتمد على بناءه للصور الذهنية التي يكونها حول البيئة والتي ترتبط وفق (lynch, 1960)وجه وتنظم حركة اإلنسان في البيئة قواعد خاصة على شكل مخططات ذهنية ت وتستند دراسات هذا المدخل أهميتها من معالجتها لمفهوم الوضوحية بشكل مباشر ولذلك سوف يتم التطرق إلى دراسات هذا المدخل بشيء من التفصيل ومن هذه الدراسات 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 34 i. دراسة(kevin lynch 1960) الموسومةthe image of the city)) لدراسات وا دراسة ، (shulz , 1971)،دراسة (david stea 1988)دراسة )التي تبنت منهجيته (mucclusky, 1979) ): كل الدراسات السابقة قد ذكرت من خالل توجهاتها في التحليل على مركبة الهوية فقط، أي عن المحيط. فهي المورفولوجية ومقدار وقوة ظهوره وتميزه هشكل الموضع الدال وخصائص تستثني مركبة المعنى، أما بالنسبة إلى المركبة الهيكلية فلم تطرح أيا من الدراسات السابقة أهمية البعد التركيبي لمواقع المواضع الدالة في الصورة الذهنية، فهي لم تذكر أي وسيلة لقياس أو ى أي من العوامل التي تفسير ظهور هذه العناصر من الجانب الهيكلي والبنيوي ولم تتطرق إل يمكن أن تؤثر فيها. باإلضافة إلى إهمال ذكرها نوع وطبيعة العالقة بين مواقع المواضع الدالة فقد كان الطرح يتناول الوضوحية من جانب سهولة إدراك وفهم البيئة الحضرية ولم يتم التركيز تخطيط المستقبلي الواضح.على العالقات بين أجزاء البيئة وأهمية هذه العالقة في عملية ال ii. سة ) دراdonald appleyard, 1976( الموسومة )planning pluralistic city :) iii. دراسة (appleyard 1980 ) الموسومة (why buildings are known ? :) iv. (دراسةrapoport 1977(الموسومة)human aspect of urban design :) v. (دراسةian bentley and others, 1985( الموسومة )responsive environment :) vi. ( دراسةbentley ،bentley,1985).) هو اهتمامها بمفهوم الوضوحية بشكل مباشر كمنطلق فعلي إن أهم ما يميز الدراسات االدراكية لقياس طبيعة وقوة العالقة بين اإلنسان والبيئة المبنية المحيطة به إذ وفرت هذه الدراسات ومن الخرائط الذهنية وسيلة لقياس وضوحية البيئة الحضرية بموجب العمليات األساسية خالل تحليل االدراكية لإلنسان في تفاعله مع البيئة المبنية. كما أشارت هذه الدراسات إلى أهمية المواضع الدالة في تعريف أجزاء البيئة الحضرية وربطت موضوع الوضوحية بسهولة تحديد هذه المواضع ما تحمله من خصائص تميزها عن باقي أجزاء البيئة المبنية ليكون مفتاح لتعريف تلك بناًء على األجزاء. )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 34 باإلضافة إلى أن الدراسات االدراكية واجهت باختالفها مشاكل في تصنيف المواضع الدالة وتحديدها، فهي تدمج بين الخصائص مع بعضها وتتجاهل أهمية األبعاد الحضارية واالجتماعية الفها باختالف المدن وتأثيرها في تحديد المواضع الدالة مما أدى إلى ظهور تصنيف خاص واخت للمواضع الدالة لكل دراسة مناسبة لها بطريقة خاصة بها لكنها تخلو من الكمال، فيجب إعادة اكتشاف المواضع الدالة الخاصة بكل بيئة حضرية وخاصة في المدن العربية والعراقية التقليدية عاصرة لما تمتلكه المدن التقليدية من ارث حضاري عربي إسالميوالم دراسات البيئة الفيزياوية: وتشمل مجموعة الدراسات التي تستند إلى دراسة خصائص التنظيم الفيزياوية كمنطلق للبحث هدف تفي العالقة بينها وبين الوضوحية كالدراسات المورفولوجية ودراسة قواعد التركيب الفضائي. ذه الفقرة محاولة تبيان موقف الدراسات من مفهوم وضوحية البيئة الحضرية على أساس ه مكانية استخدام هذه المقاييس في درا سة الواقع المحلي شموليتها وموضوعية ودقة مقاييسها وا -ومن هذه الدراسات :للبيئة الحضرية i. دراسة نظرية المخطط (graph theory approach ): ii. التركيبي: دراسة دراسات التحليل (hillier&harson,1984)الموسومة(the social logic of space) :ومجموعة دراسات أخرى iii. دراسة (hillier 1996 ( )space is the machine :) توفر منهاجًا دقيقًا لقياس (space syntax)منهجية قواعد التركيب الفضائي ان نستنتج فضائي وبالتالي وضوحيته مع إمكانية القياس الدقيق على المستوى ووصف وتحليل بنية النظام ال .الشمولي والموضعي والعالقة بينهما استخالص مشكلة البحث من خالل االطالع على الدراسات السابقة لموضوع وضوحية البيئة الحضرية تم تحديد فجوة لتركيبية )على المستوى ان لتغيير الخصائص ا-معرفية وتم تحديد مشكلة البحث الرئيسية : الشمولي والموضعي( اثر متباين بوضوحية الصورة الذهنية للمتلقي وبتحديد مواقع النقاط الدالة -في المدينة مما استدعى تسليط الضوء ودراسة المشكلة . وتم تحديد المشكلة الثانوية: بوجود قصور معرفي يوضح مدى عالقة تغير خاصية سيطرة الفضاء الحضري -1 عيا بتوقيع وتحديد المواضع الدالة كأحد خصائص وضوحية الصورة الذهنية موض للمتلقي. 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 بوجود قصور معرفي يوضح مدى عالقة تغير خاصية درجة التكامل الشمولية -2 للفضاءات الحضرية بتوقيع وتحديد المواضع الدالة كأحد خصائص وضوحية الصورة الذهنية للمتلقي. فرضية البحث البحث تم تحديد فرضية البحث الرئيسية بان وضوحية الصورة الذهنية تتاثر ولفحص مشكلة بتغيير الخصائص التركيبية )الشمولية والموضعية (للنظام الفضائي في المدينة .كما تم تحديد -فرضيات البحث الثانوية باالتي: لدالة وظهور المواضع اهناك عالقة طردية بين ازدياد درجة سيطرة الفضاء الموضعي -1 كأحد خصائص وضوحية الصورة الذهنية للمتلقي. درجة التكامل الشمولية وظهور المواضع الدالة كأحد هناك عالقة عكسية بين ازدياد -2 خصائص وضوحية الصورة الذهنية للمتلقي. اهداف البحث -تمثلت اهداف البحث بمجموعة من االهداف النظرية تمثلت باالتي: i. القة تأثير خصائص التنظيم الفضائي في توقيع النقاط الدالة في محاولة معرفة طبيعة ع المدينة. ii. .معرفة مدى تاثير تغير خصائص التنظيم الفضائي بوضوحية الصورة الذهنية للمتلقي iii. الوصول الى مؤشرات ومحددات تساهم في تطوير تخطيط المدن التاريخية ورفع مستوى -هداف العملية باالتي :وتمثلت االاداء هذه المدن وعدم اندثارها. i. محاولة استثمارمقاييس النظريات االدراكية والتركيبية في دراسة الواقع المحلي للبيئة الحضرية في المدينة. ii. تحديد العالقة بين تغيير خصائص النظام الشمولية المتمثلة بنواة السيطرة الشمولية دينة كاحد خصائص وضوحية للنظام الفضائي وفعالية توقيع النقاط الدالة في الم الصورة الذهنية وباسلوب رياضي تحليلي . iii. تحديد العالقة بين تغيير خصائص النظام الموضعية المتمثلة بنواة السيطرة الموضعية للفضاءات الحضرية وفعالية توقيع النقاط الدالة في المدينة كاحد خصائص وضوحية الصورة الذهنية وباسلوب رياضي تحليلي . نطاق البحث )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 وضمن مراحل زمنية التاريخيةانتخاب النظام الفضائي لمدينة الكفل البحث ب تم تحديد نطاق تم تحليل مركز مدينة الكفل)كحالة دراسية( بقسميه القديم التقليدي والحديث الشبكي و مختلفة . وقد افتقرت الزهراء،حي الحسين( بناءا على المنهج التركيبي واالدراكي )المدينة القديمة ،حي بهدف تحديد هوية المدينة وقد تم انتخاب هذه المدينة هذه المدينة التاريخية الى التوثيق العمراني والاهميتها اوال،من خالل تحديد المفاهيم والقيم التصميمية والتخطيطية للنسيج الحضري وكما تمثل تقاطع مهم لثالث محافظات هي النجف وبابل وكربالء لجغرافية فهي التاريخية وا )خصائص النظام الفضائي الشمولية كما تم تحديد العوامل المستقلة .(3مبينة بالشكل رقم ) المتمثلة بنواة السيطرة الشمولية وخصائص النظام الموضعية المتمثلة بنواة السيطرة الموضعية( يرة للبحث) وضوحية الصورة الذهنية للمتلقي من خالل تحديد فعالية تحديد مواقع والعوامل المتغ النقاط الدالة في النظام الفضائي كاحد خصائص الصورة الذهنية(. منهجية البحث -وقد تبني البحث اليات القياس االتية :ولتحقيق اهداف البحث اعتمدت المناهج التحليلية يبية للهياكل الفضائية للمناطق المنتخبةقياس الخصائص الترك -اوال: وهي (space syntax)التحليل التركيبي من خالل استخدام امكانيات نظرية تركيب الفضاء طريقة حسابية في تحديد اوزانا رقمية للهيكل الفضائي تعبر هذه االوزان عن قوة العالقات النسبية الفضائية بنيويا وتثبت هذه الطريقة قيما الجزاء الهيكل.و هي طريقة حسابية في تحليل النظم رقمية للفضاء نسبة الى قوة عالقته في النظام الكلي.وقد وضعت الطريقة صيغة بصرية للتعبير عن تلك القيم بتصنيفها الى مجاميع وفقا الى التماثل الرقمي فيما بينها ،ويعبر عن كل مجموعة ,hillier, bill and hanson)المصدرينبسمك خط مختلف للخطوط وهذه الطريقة منشورة في للهياكل الفضائية للعينة (integration)تم قياس درجة التكامل (hillier,bill,1996(و)1984 -المنتخبة من خالل استخدام المعادالت االتية: .. .........( mean depthخاصية معدل العمق النسبي الشمولية ) -1 1   k dk md md ........قيمة خاصية معدل العمق النسبي=dk عمق الفضاءات االخرى نسبيا الى الفضاء االساسي = = عدد الفضاءات k ويحسب من عدد الخطوات البصرية التي نبتعد بها عن الفضاء األساسي........ ( hillier&hanson ,1984 , p. 108) .المحورية يعبر مؤشر التكامل عن : ( integration degree) خاصية درجة التكامل الشمولية -2 عالقة الفضاء نسبة إلى كل فضاءات النظام االخرى في المخطط درجة تكامل 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 المحوري وتعتبر مؤشر حيوي لحركة الغرباء في المنظومة، ولحسابها رياضيًا باستخدام  ....................................... المعادلة اآلتية  2 12    k md ra ra( قيمة خاصية معدل عدم التناظر النسبي =relative asymmetry والذي يمثل قيمة التكامل ) = عدد الفضاءات المحورية في النظام. k.......= معدل العمق النسبي...... mdالشمولي...... ة ( إلى أعلى درج0( ، حيث تشير القيم القريبة من ) 1-0يتراوح قيم التكامل بين ) ( إلى اقل درجة1تكامل للفضاء نسبيًا الى الفضاءات االخرى للنظام ، والقيم القريبة من ) ( hillier&hanson ,1984 , p. 109) .تكامل أي الفضاءات تكون معزولة : (integration degree regulated)خاصية درجة التكامل الشمولية المعدلة -3 dk ra rra  rra خاصية عدم التناظر النسبي المعدلة..... = قيمةra قيمة خاصية عدم التناظر النسبي = درجة عدم التناظر النسبي للفضاء االساسي للمخطط العمق الجوهري الشكل = dkللفضاء...... ( إلى الفضاءات األكثر تكامال 1( وتشير القيم األقل من )1وتكون القيم الناتجة حول العدد ) , hillier&hanson ,1984) ( إلى الفضاءات األكثر عزلة.1التي تزيد عن ) وتشير القيم p. 113 ) ( : تشير هذه الخاصية الى درجة الخيار local controlخاصية السيطرة الموضعية ) -4 الموضعية التي يوفرها الفضاء لكل الفضاءات المجاورة له مباشرة ، وتحسب رياضيا من ..............المعادلة n 1 ev ev خاصية السيطرة الموضعية=قيمة .......n االرتباطات الموضعية لكل محور = ( عن 1( ، حيث تغير القيم التي تتجاوز العدد ) 1تترواح قيم السيطرة الموضعية حول العدد ) ات السيطرة ( تعبر عن الفضاءات ذ1الفضاءات التي تمتلك سيطرة عالية والقيم التي تقل عن ) :( hillier&hanson ,1984 , p. 109) الضعيفة . الخصائص التركيبية للنظام الفضائي في المدينة نتائج قياس تم اعاله و تحليل خصائص النظام الشمولية والموضعية للمدينة ومن خالل تطبيق المعادالت نواة العزل ونواة السيطرة الشمولية تحديد نواة التكامل الشمولية لالنظمة الفضائية المنتخبة وتحديد وكما مبينة في المخططات المرفقة وقد تميزت الثالثةلمراحل تطور المدينة ودرجة الخيار -خصائص النظام الفضائي باالتي: ويهدف العمق الشمولي إلى تحديد عدد نتائج خاصية درجة التكامل الشمولية المعدلة للمدينة ء معين بنسبة إلى كافة فضاءات المنظومة ومن الواضح أن الخطوات التي يبعد بها فضا الفضاءات في المنطقة القديمة ذات التخطيط العضوي التقليدي أكثر عمقا من فضاءات المناطق )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 الحديثة بسبب طبيعة التخطيط . كما وان قيم العمق في المنطقة القديمة تكون متدرجة من ات العمق الواطئ . المناطق ذات العمق العالي الى المناطق ذ -8.730وقد أشارت النتائج في الدراسة العملية إلى أن قيمة هذه الخاصية تراوحت ما بين ) ( في المنطقة القديمة. أما بالنسبة إلى المرحلة الثانية فقد كانت النتائج 1.31( بمعدل ) 2.402 ة فقد كانت النتائج بين ( . اما بالنسبة للمرحلة الثالث1.10( بمعدل ) 2.341-8.702بين ) (. على الرغم من تقارب قيم معدل التكامل الموضعي لكال 8.0( بمعدل ) 8.714-2.30) المنطقتين إال ان قيم التكامل الموضعي للمنطقة القديمة تكون متدرجة نسبيا من الفضاءات ذات مي للمنظومة التكامل العالي إلى الفضاءات ذات التكامل الواطئ وذلك يعكس التدرج الهر الفضائية في المناطق ذات التخطيط التقليدي العضوي . تراوحت نتائج قيمة خاصية السيطرة الموضعية نتائج قيمة خاصية السيطرة الموضعية للمدينة ( ، بالنسبة إلى 1.2( أي بمعدل )2.13-8.333في المنطقة القديمة في المرحلة االولى بين) ( بمعدل 3-8.1.7ية للمدينة في المرحلة الثانية فقد تراوحت بين )نتائج قيمة السيطرة الموضع ( وتشير درجة السيطرة الموضعية العالية إلى درجة سهولة الحركة الموضعية التي .1.17) يوفرها الفضاء للحركة إليه من الفضاءات المجاورة بشكل مباشر. اما في المرحلة الثالثة فقد (. بمقارنة معدل السيطرة الموضعية 8.000( اي بمعدل )2.13-8.1.7تراوحت النتائج بين) للمدينة بالمراحل الثالثة لوحظ إن معظم فضاءات منطقة المدينة القديمة كانت متطرفة ومعظمها بعيدة عن المعدل مقارنة بنتائج قيم خاصية السيطرة للمناطق الحديثة التي كانت قريبة رمي في طبيعة عالقة فضاءات المنظومة بالفضاءات إلى المعدل ويرجع السبب إلى التدرج اله األخرى . -ومن خالل مطابقة نواة التكامل الشمولية مع نواة السيطرة الموضعية تبين االتي: يطرة العالية تطابق ان نواة الس -المرحلة االولى )المدينة القديمة قبل اضافة الشوارع(: -1 لحركية وهذا يعني ان النظام يتميزبوجود % من المحاور ا.1العالي بنسبة نواة التكامل نواة سيطرة شمولية وتعتبر هذه الفضاءات ذات سيطرة قوية نسبة الى جميع فضاءات النظام وتوفر امكانية عالية من الخيار في االنتقال من خاللها الى جميع اجزاء حاور % من الم31النظام.اما نواة العزل فتتطابق مع نواة السيطرة الضعيفة بنسبة محققة بذلك فضاءات ذات سيطرة غير فعالة ومعزولة ويصعب الوصول اليها من جميع فضاءات النظام كما ان هذه الفضاءات التوفر اي درجة للخيار في االنتقال الى 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 % من الهيكل الفضائي للمدينة 17الفضاءت االخرى وهي فضاءات قليلة وتشكل نسبة (..ككل.وكما موضحة بالشكل رقم) ان نواة السيطرة العالية تطابق -مرحلة الثانية )المدينة القديمة بعد اضافة الشوارع(:ال -2 % من المحاور الحركية وهذا يعني ان النظام يتميزبوجود 40نواة التكامل العالي بنسبة نواة سيطرة شمولية وتعتبر هذه الفضاءات ذات سيطرة قوية نسبة الى جميع فضاءات عالية من الخيار في االنتقال من خاللها الى جميع اجزاء النظام وتوفر امكانية % من المحاور 17النظام.اما نواة العزل فتتطابق مع نواة السيطرة الضعيفة بنسبة محققة بذلك فضاءات ذات سيطرة غير فعالة ومعزولة ويصعب الوصول اليها من ار في االنتقال الى جميع فضاءات النظام كما ان هذه الفضاءات التوفر اي درجة للخي % من الهيكل الفضائي للمدينة 17الفضاءت االخرى وهي فضاءات قليلة وتشكل نسبة تطابق بين نواة التكامل العالية مع نواة السيطرة الضعيفة بنسبة كما ان هناكككل. ات نواة سيطرة منتشرة اي انها فضاءات توفر درجة ذ% محققة بذلك فضاءات 33 االنتقال من خاللها الى الفضاءات المجاورة فقط وليس الى جميع عالية من الخيار في (.7اجزاء النظام.وكما موضحة بالشكل رقم) ان نواة السيطرة -المرحلة الثالثة )المدينة القديمة مع محلة حي الحسين والزهراء(: -3 % من المحاور الحركية وهذا يعني ان 12العالية تطابق نواة التكامل العالي بنسبة النظام يتميزبوجود نواة سيطرة شمولية وتعتبر هذه الفضاءات ذات سيطرة قوية نسبة الى جميع فضاءات النظام وتوفر امكانية عالية من الخيار في االنتقال من خاللها الى جميع اجزاء النظام وجميعها ضمن المنطقة القديمة.اما نواة العزل فتتطابق مع نواة % من المحاور محققة بذلك فضاءات ذات سيطرة غير 17السيطرة الضعيفة بنسبة فعالة ومعزولة ويصعب الوصول اليها من جميع فضاءات النظام كما ان هذه الفضاءات التوفر اي درجة للخيار في االنتقال الى الفضاءت االخرى وغاليبيتها تقع واة السيطرة ضمن المنطقة الجديدة .كما ان هناك تطابق بين نواة التكامل العالية مع ن % محققة بذلك فضاءات ات نواة سيطرة منتشرة اي انها 11.1الضعيفة بنسبة فضاءات توفر درجة عالية من الخيار في االنتقال من خاللها الى الفضاءات المجاورة فقط وليس الى جميع اجزاء النظام وهي تقع ضمن المنطقة القديمة .وكما موضحة (. 0بالشكل رقم) وضوحية الصورة الذهنية للمتلقي قياس-ثانيا : )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 تم تحديد مواقع العالمات الدالة في المدينة من قبل الباحث بالمسح الميداني واستنادا (garling tommy,andevs book and evik lindbreg,1986) دراسة [الى وحسب اختالف الخصائص التصميمية )الحجم / الشكل / اللون / والطراز المعماري / the image of the( الموسومة kevin lynch 1960) اختالف الوظيفة(.وكذلك دراسة city)) وشخصت الدراسة خمس عناصر أساسية )كمواضع دالة( اعتبرتها مسؤولة عن ، الحافات: (landmarks)، الشواخص (paths)وضوحية البيئة الحضرية الممرات (edges) القطاعات ،(districts) ديد هذه المواقع من قبل المتلقي وحسب وايضا تم تح ( .0الشكل رقم )ماورد في استمارات االستبيان.وكما موضحة في إعداد استمارة االستبيان وللتعرف عن مدى وضوحية هذه النقاط الدالة بالنسبة للمتلقي تم اعداد استمارة استبيان و يهدف مواقع المواضع الدالة للبيئة األسلوب الى استكشاف خصائص الصورة الذهنية الخاصة ب الحضرية للعينة المنتخبة .ومن اجل رفع مستوى دقة وشمولية المعلومات الصورة الذهنية المستحصلة من األشخاص في مجتمع البحثي.تفضل الدراسة االعتماد علي مجموعة آليات تي حددها الباحث الحصول على معلومات الذهنية األولى تتمثل باعطاء اسماء المواقع الدالة ال واضافة مواقع اخرى من قبل الناس لتحديد مواقع المواضع الدالة والثانية اسئلة عن مناطق يتذكرها الشخص المار بالمدينة والثالثة رسم مايتذكره من المدينة.وقد تضمنت االستمارة محورين خ ، المحور الثاني ال… األول متعلق بمتغيرات مرتبطة بالفرد والتي تتعلق بالعمر والجنس مرتبط بمتغيرات البيئة الحضرية والتي تتضمن القدرة على وصف وتذكر المنطقة واجزاءها تم تقديم استمارة لفئات مختلفة من المتمثلة باهم المعالم المميزة والمواضع الدالة لتلك المنطقة . (سنة 41-11)(،االناث من عمر41-11الناس)عينة من سواق التكسيات، الذكور من عمر بغية التوصل لتحديد الصورة الذهنية للمتلقي في المدينة وكما مبينة في االستمارة المرفقة في (2الملحق رقم ) نتائج قياس وضوحية الصورة الذهنية وتوقيع الموضع الدال أظهرت النتائج العالقة بين خاصية التكامل وظهور مواقع المواضع الدالة. فقد ظهر -1 جمل مواقع المواضع الدالة ضمن نواة التكامل القوية ، كما لم يظهر أي %( من م71) موقع للمواضع الدالة داخل نواة التكامل الضعيفة. من خالل نتائج نالحظ وجود عالقة قوية بين مواقع المواضع الدالة وهذه الخاصية وذلك لما توفر من قوة تكامل لفضاء مع 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 موقع الموضع الدال . وما يمكن تضيفه هذه باقي الفضاءات المرتبطة به لتحديد (. 11،12رقم ) االشكالالخاصية النجاح موقع الموضع الدال وكما مبينة في أظهرت النتائج العالقة بين خاصية نواة السيطرة الشمولية وظهور مواقع المواضع الدالة. -2 لية القوية ، %( من مجمل مواقع المواضع الدالة ضمن نواة السيطرة الشمو 71فقد ظهر ) كما لم يظهر أي موقع للمواضع الدالة داخل نواة السيطرة الشمولية الضعيفة. من خالل نتائج نالحظ وجود عالقة قوية بين مواقع المواضع الدالة وهذه الخاصية وذلك لما توفر هذه الفضاءات ذات السيطرة قوية نسبة الى جميع فضاءات النظام وتوفر امكانية عالية يار في االنتقال من خاللها الى جميع اجزاء النظام وجميعها ضمن المنطقة من الخ لدال . وكما مبينة في القديمة . وما يمكن تضيفه هذه الخاصية النجاح موقع الموضع ا (.14الشكل رقم ) هرت النتائج مقياس لقوة العالقة بين خاصية السيطرة كأحد خصائص التنظيم الفضائي ظا -3 اقع المواضع الدالة كأحد خصائص الصورة الذهنية ضمن نواة الموضعي وظهور مو %( من مجمل مواقع المواضع الدالة ضمن 03السيطرة القوية والضعيفة . حيث ظهر ) نواة السيطرة القوية كما لم يظهر أي موقع لموضع دال داخل نواة السيطرة الضعيفة . إلى مواقع المواضع الدالة ، ويمكن ان نستنج مما سبق أهمية خاصية السيطرة بالنسبة فظهور مواقع المواضع الدالة ضمن نواة السيطرة القوية يبين ما توفره خاصية السيطرة من درجة اختيار موضعية التي يوفرها نظام الحركة إليها من الفضاءات المجاورة بشكل لدالة كما مباشر وبالتالي سهولة الحركة إليها من الفضاءات المجاورة لمواقع المواضع ا (. 11،13مبينة في الشكل رقم ) االستنتاجات النهائية ومواقع ونواة السيطرة الموضعية ة المنتخبة يوبعد مطابقة نواة التكامل الشمولية للنظم الفضائ -وضوح بالنسبة للمتلقي توصل البحث إلى االتي : النقاط الدالة االكثر م الفضائي وتوقيع المواضع الدالة وجود تأثير متباين القوة بين خصائص التنظي -1 باالعتماد على خصائص التنظيم الفضائي. أظهرت قراءة نتائج قيم خصائص التنظيم الفضائي الفرق بين طبيعة المنظومة الفضائية -4 لكل من منطقتي الدراسة واالختالف الواضح بين طبيعة نمط التخطيط الشبكي الحديث الخصائص الموضعية والشمولية للتنظيم والتخطيط التقليدي العضوي على مستوى الفضائي . فالتخطيط الشبكي تميز بقيم متقاربة للتكامل الشمولي واوطئ للخيار الشمولي. )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 34 هرت النتائج عزلة الفضاءات ضمن المنطقة الحديثة حيث لم تميز فيها نواة تكامل ظا -1 نواة تكامل شمولية للمتلقي في حين تميزت المدينة القديمة بوجود ةضحاشمولية تجعلها و واضحة في المراحل الثالثة مما جعلها اكثر حيوية. التوصيات -باالتي: يوصي البحث للمدن اثناء ذات الخصائص الشكلية المختلفة بدارسة الخصائص التركيبية للنظم الفضائية -1 مرحلة التخطيط ءات ذات االستراتيجية العالية تحليل واقع الحال بالنسبة للنظم الفضائية القائمة وتحديد الفضا -2 ضمن النظام والسيطرة القوية ومن ثم تحديد مواقع الفعاليات المهمة للمدينة دراسة تخطيط المدن التاريخية وخصائص انظمتها الفضائية التي تمثل انعكاس للخصائص -3 االجتماعية والدينية والبيئية للتلك المدن المصادر 1. rapoprot, a.: human aspect of urban form. pergamon press inc elmsford, ny (1977) 2. lynch, k.: the image of the city.: mit press cambridge, ma (1960) 3. lynch, k. " reconsidering the image of the city. in l. rodwin and r. m. hollister (eds),cities of the mind: images and themes of the city in the social sciences, new york: plenum press,(1984). 4. hillier, bill and hanson,julienne,"the social logic of space" cambridge university press,1984 5. hillier,bill,"space is the machine:aconfigurational theory of architecture, cambridge university press,1996 6. g. cullen. the concise townscape. butterworth architecture, 1961. 7. remco chang, ginette wessel& athers," legible cities: focus-dependent multi-resolution visualization of urban relationships, "unc charlotte ,college of architecture &department of computer science, 8. mccluskey,jim,"road form and townscape",london,the architectural press. 1979 9. appleyard, d. a. (1976). planning a pluralistic city. cambridge, mass.: mit press 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 34 10. appleyard, donald (notes on urban perception and knowledge), in j. archea and c. eastman edraz. 1970. 11. remco chang, thomas butkiewicz,&athers,"legible simplification of textured urban models",unc charlotte,2007 12. lynch, k. (1981) a theory of good city form (cambridge, ma, mit press). 13. schultz, norderg, christian (existence space and architecture) studio vista, london, 1971. 14. bonta, john;" architecture and it's interpretation"; n.y. 1979. 15. broadbent, g. (design in architectural) johnwiley and sons, london, 1973. 16. curtis, william; (modern architecture since 1900) phadiam, new york, 1982. 17. kaufman, sarah (lectures de derrida) galilee, paris 1984. 18. ghirardo, diane (les architectures postmodernes) thomas & hudson, paris, 1996. 19. bentley i. eta (responsive environments) the architectural press london, 1985. 20. thierry r. and gabriel m. (social legibility, the cognitive map and urban behavior) journal of environmental psychology), 1998. 21. kithchin, rob & scott freundschuh (the future of cognitive mapping research) in kitchin, rob & scott freundschuh, (cognitive mapping past, present and future) routledge, london and new york, 2000. 22. garling tonny, ander book and erik linberg (spatial orientation and way finding in the designed environment. a conceptual analysis and some suggestion for post occupancy evaluation) in journal of architectural and planning research, volume 3 numberl, february 1986. 23. appleyard, donald (why building are known: a predictive tool for architects and planners) in g. broad bent, r. bunt and t. liorens (eds.) (meaning and behavior in the building environment), john wileyand sons. ltd., (1980). 24. bentley i. eta (responsive environments) the architectural press london, 1985. 25. steadman, j. p. (architectural morphology) pinot ltd. london, 1983. 26. levi, strauss,(structural anthropology)in(method in environmental design), 1967. للفضاءات الذهنية الصورة بنية وهوية شاكر،" العولمة عامر.زق،خضير ،د عبدالرا حيدر.د.كمونة،ا .27 جامعة بغداد \واالقليمي الحضري للتخطيط العالي الحضرية "،بحث منشور ، مجلةالمخطط والتنمية، المعهد ،2002 )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 34 اعداد الباحث مخطط يوضح مكونات البيئة الحضرية 1شكل مصفوفة لتقيم وضوحية موضع دال والذي يمثل بناية من اجل التوصل إلى قيمة أولية 2شكل في مدى ضعف قدرته على اإلدالل باالعتماد على بعض الخصائص الشكلية والتخطيطية (22المصدر : ) 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 33 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 33 2ملحق بسم اهلل الرحمن الرحيم قسم الهندسة المعمارية \كلية الهندسة \جامعة بابل استمارة استبيان وضوحبة البيئة الحضرية في مدينة الكفل التاريخية اشر بعالمة ) ( امام المعلومة الصحيحة خصائص عامة عن االفراد -اوال: انثى...... الجنس ذكر...... -1 العمر ...............-2 امااااااااااااااااي ...... .... ابتدائيااااااااااااااااة ......... متوسااااااااااااااااطة ......... اعداديااااااااااااااااة....... -المسااااااااااااااااتوى التعليمااااااااااااااااي: -3 جامعة....... تعليم عالي.......... .................. المهنة -4 هاااااااااااااااال اناااااااااااااااات ماااااااااااااااان سااااااااااااااااكان المدينة...................اساااااااااااااااام محلااااااااااااااااة لسااااااااااااااااكن............. ريب عاااااااااااااااان -5 المدينة.............. المشااااااااااااي ....... الدراجااااااااااااة ....... -ماااااااااااااهي وساااااااااااايلة النقاااااااااااال المسااااااااااااتخدمة بااااااااااااين البياااااااااااات ومحاااااااااااال العماااااااااااال : -5 السيارة....... العالمات المميزة -ثانيا: عربالراحة داخل المحلة...............................هل تش -1 هل تشعر باالمان خالل االنتقال داخل المحلة ................ -2 هل تشعر بالخوف اثناء االنتقال داخل المحلة................ -3 هل تشعر بالملل داخل المدينة.........لماذا.................. -4 ي مكان داخل المدينة............ او العكس.......هل تشعر بصعوبة الوصول ال -5 عنااااااادما تركاااااااب سااااااايارة مواصاااااااالت برحلتاااااااه اليومياااااااة اي االمااااااااكن واضاااااااحة ويساااااااتدل بهاااااااا ساااااااائق التكساااااااي -6 للوصول للمكان المطلوب ......... ماااااااااهي اهاااااااام الشااااااااوارع التااااااااي تتااااااااذكرها فااااااااي المدينااااااااة وخااااااااالل رحلتااااااااه اليوميااااااااة..................... هاااااااال -2 -لشارع بسبب:تتذكر ا اشر بعالمة اشر بعالمة اخاااااااااااتالف تصاااااااااااميمه عااااااااااان الشاااااااااااوارع ان عرض الشارع كبير المجاورة محاط بابنية عالية اختالف االلوان يااااااوفر خيااااااار االنتقااااااال الااااااى اكثاااااار ماااااان شارع يؤدي الى ساحة تجمع يحتوي شاخص مدينة الكفل التاريخية في )حي الزهراء وحي الحسين(يقوم اساتذة قسم الهندسة المعمارية بدراسة وتحليل البيئة الحضرية للمناطق القديمة والحديثة ها في في محاولة للتعرف على مدى وضوحية هذه البيئة لالنسان المار من خاللها وللتعرف على المشاكل والمعوقات التخطيطية في المدينة وتقليل هذا البحث لالغراض العلمية شاكرين تعاونكم معنا. المستقبل . لمدينة الكفل التاريخية للبيئة الحضرية التحوالت التركيبية -اسم البحث: )دراسة تحليلية حول اثر غيرالخصائص وضوحية البيئة الحضرية لمدينة الكفل التاريخية واقع الدالة في مدينة الكفل التركيبية للتنظيم الفضائي بوضوحية الصورة الذهنية وتحديد الم التاريخية ( 34 مديناااااااااااة ................................ هااااااااااال تتاااااااااااذكر مااااااااااااهي اهااااااااااام السااااااااااااحات التاااااااااااي تتاااااااااااذكرها فاااااااااااي ال -8 -الساحات بسبب: اشر بعالمة اشر بعالمة اخااااااااااتالف تصااااااااااميمه عاااااااااان الساااااااااااحات ان ابعادها كبيرة االخرى محاط بابنية عالية اختالف االلوان تاااااااوفر خياااااااار االنتقاااااااال الاااااااى اكثااااااار من طريق يحتااااااااااااوي شاااااااااااااخص او عناصاااااااااااار بناء مميزة -ماهي اهم االبنية التي تتذكرها من المدينة........................... هل تذكر ها بسبب: -9 -الشواخص والنصب التي تتذكرها من المدينة................. هل تذكرها بسبب: ماهي اهم -10 اشر بعالمة اشر بعالمة امكانيااااااة الوصاااااااول اليهااااااا مااااااان عااااااادة ان ابعادها كبيرة طرق ارتفاعها كبير اختالف االلوان اختالفهاااااااااا بالتصاااااااااميم ماااااااااع البنياااااااااة المجاورة -لتقاطعات التي تتذكرها في المدينة هل تذكرها بسبب:ماهي اهم ا -11 اشر بعالمة اشر بعالمة امكانية الوصول اليها من عدة طرق ان ابعادها كبيرة وجود ابنية مهمة تحيطها اختالف االلوان اختالفهااااااااااااااا بالتصااااااااااااااميم مااااااااااااااع المجاورات بيئتااااااه ويمكناااااااه الوصاااااااول اليهااااااا بااااااادون ان تساااااااال اشاااااار بعالماااااااة ) ( علااااااى االمااااااااكن التاااااااي تااااااذكرها مااااااان -12 اي شخص من المدينة اشر بعالمة اشر بعالمة امكانيااااااة الوصاااااااول اليهااااااا مااااااان عااااااادة ان ابعادها كبيرة طرق ارتفاعها كبير اختالف االلوان اختالفهاااااااااا بالتصاااااااااميم ماااااااااع البنياااااااااة المجاورة 1023 لسنة -ولاال العدد س،داسال المجلد الهندسيه، للعلوم القادسيه مجلة 34 دينااااااة ولاااااام يااااااتم ذكرهااااااا فااااااي اذكاااااار اماااااااكن اخاااااارى تتااااااذكرها وهااااااي مهمااااااة بالنساااااابة لااااااه كنقطااااااة دالااااااة داخاااااال الم -13 الجدول ارسم بمخطط بسيط ماتتذكره من المدينة -14 شكرا لتعاونكم معنا....الباحثة اشر بعالمة ) ( النقاط الدالة ت اشاااااااااااااااااااااااار بعالمة ) ( ت النقاط الدالة مرقد نبي اهلل ذي الكفل 15 جامع الكفل الكبير مة قدي ال ينة مد ال 1 2 منارة المرقد 16 مدرسة ابو ذر المختلطة 3 مسجد النخيلة 12 رشيد الهجري متوسطة 4 سوق العرايا 18 متوسطة الكفاح 5 سوق دانيال 19 مستشفى الكفل العام 6 مواقف سيارات 20 كراج بني مسلم 2 مركز ماء الكفل 35 حسينية 8 هيئة اتحاد النساء 36 سوق 9 كفلدائرة االحوال المدنية في ال 32 حمام الكفل القديم 10 مركز شرطة 38 سوق 11 دائرة الري 39 سوق 12 المحكمة 40 علوة السمه 13 مركز مجاري الكفل 41 سوق 14 المجلس البلدي سوق مخزن تمور الكفل 22 موقف سيارات راء لزه ي ا ح 42 21 مخزن تمور الكفل 43 مدرسة ابتدائية 22 دائرة البلدية 44 روضة 23 دائرة الكهرباء 45 منطقة مفتوحة 24 مدرسة الكفل االبتدائية 46 محطة تعبئة 42 منطقة مفتوحة كاااااااااااااراج حاااااااااااااي الشااااااااااااارطة والحاااااااااااااي العسكري 25 26 الكراج الموحد مخازن تمور اهلية 48 مدرسة ثانوية مع ساحة مفتوحة ين حس ال حي 28 29 مصرف الرشيد 49 مدرسة ثانوية 30 المستوصف البيطري 50 ساحة مفتوحة 31 جملون تابع للبلدية 51 ساحة مفتوحة 32 مسجد حسينية 52 محطة تعبئة 33 المركز الصحي في حي الحسين 53 مدرسة ابتدائية 34 كراج البلدية article al-qadisiyah journal for engineering sciences 12 (2019) 017–024 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964-07714856361. e-mail address: bashar.a@uokerbala.edu.iq (bashar a. fadheel). https://doi.org/10.30772/qjes.v12i1.582 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. design of an rlc compensator for a synchronous motor: torque ripple improvement bashar a. fadheel a* adepartment of biomedical engineering, college of engineering, university of kerbala. a r t i c l e i n f o article history: received 05 january 2019 received in revised form 15 march 2019 accepted 30 march 2019 keywords: ac-drive system pmsm torque ripple improvement rlc compensator ac-dc converter speed control a b s t r a c t ac-drive systems based permanent magnet synchronous motor (pmsm) are widely utilized in industrial applications due to many advantages including excellent efficiency, best reliability, and low-effective cost compared with dc-drive systems. design and implementation of an rlc compensator for a pmsm-drive system is demonstrated in this paper. the main aims of using an rlc compensator are decreasing of totalharmonics-distortion (thd) of the input line current and ripple factor (rf) of the electromagnetic torque over a wide range variation in rotor speed and load. the entire transfer function of the proposed system is derived for stability verification under the change of rotor speeds. the proposed pmsm-drive system is implemented with and without rlc compensator for two cases; which are at a fixed load and a step-change in load. good performance is achieved using the proposed rlc compensator; in terms of thd and rf are 0.77% and 3.13%, respectively. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction ac-drive systems are essential for industrial and home utilizations due to (i) satisfying reliability, (ii) excellent efficiency and (ii) low maintenance cost compared to dc drives and ac drives based induction motors. in spite of these numerous advantages, pmsm-drive systems have, minor drawback related to increasing ripple in electromagnetic torque. the variations in rotor speed are increasing ripple in torque, which should be decreased by using adequate techniques [1]. in [2], a comparison between three control techniques has been demonstrated that related to chattering reduction for a speed controller. in [3], a hybrid space-vector based on pulse width modulation (pwm) technique has been represented for minimizing the ripple in electromagnetic torque for a pmsm-drive system based on different switching topologies. basically, the ripple in electromagnetic torque of a pmsm-drive system causes mechanical stresses. in that paper, an accurate speed controller has been implemented to minimize mechanical vibrations and noise [4]. for electric vehicles, high torque with a wide speed range is required. few disadvantages in pmsm-drive systems, such as cogging reluctance torque which causes ripples in torque [5].typical fieldoriented control (foc) for pmsm-drive systems based on dynamic mathematical equations, so the variations of parameters (e.g. electromagnetic interface, distorted flux and harmonics in the line currents), lead to low performance. in addition these drawbacks cause: oscillations in speed, ripples in torque, distortions in line currents consequently increasing thd [6]. the cause of increasing ripple in torque is due to the trapezoidal wave form of the flux around the air-gap and variable mutual reluctance due to the shape of stator slots [7]. the market of pmsm-drive systems is growing http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 18 bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 because of low cost and high reliability. these drive systems have conventional utillizations for fast dynamic position drives and machine manipulation shaft drives, due to their torque-to-losses ratios, the effects of ripple in torque that decay the machine lifespan and position path especially at high-speeds, the noises and losses are increased [8]. in [9], a dead time compensation strategy has been proposed to mitigate the motor torque ripple for an 80 kw pmsm. in that paper, rf has been reduced from 30.3% to 22.3%. in [5], the vibration caused in a driver was analyzed for a pmsm. it was obtained that in low speeds, the drive system is sensitive to torque ripple which was 10 n.m without any compensator system. in [10], a developed method based on a dead-beat region between conduction and natural commutation zones has been presented for the torque-ripple reduction in a pmsm-drive system. the input signals of the controller were back-emf and the change of the back-emf during the commutation period. in [11], a developed integrated dual-output converter including switch selector has been proposed for reducing ripples in torque during a commutation period. good performance has been achieved compared with a conventional converter. in addition, the ripples in torque during the commutation period have been improved in [12] by optimizing the currentloop controller of a pmsm-drive system. it was illustrated in [13] that the optimizing of the reluctance torque to a minimum value is not adequate to get low ripples in torque. in [14], an adaptive controller based on selfcommissioning was proposed for a pmsm-drive system according to ripples reduction in torque. a torque predictive controller based on the improved voltage vector controller has been experimentally implemented in [15] for torque-ripple minimizing. also, in [16], the design of a pmsm has been improved based on rotor permanent-magnets skewing angle for decreasing the ripples in torque. improved field-reconstruction controller has been represented in [17] for minimizing the ripples in torque for a pmsm-drive system which causes many problems; such as vibration during operation and increasing harmonics in back-emf. in this paper, an rlc compensator is designed for a pmsm-drive system based synchronous motor to achieve minimum ripples in electromagnetic torque by improving thd of the input line current. the design is based on optimally matching between rlc compensator and a pmsm under the variations of rotor speeds and mechanical torque. the entire transfer function of the drive system is derived for stability analysis. the simulation results show the high performance using rlc compensator in a wide range of rotor speeds (500-1500) rpm. the scheme of the pmsm-drive system studied in this paper is shown in fig.1. including a pmsm, a three-phase inverter, and an rlc compensator. rlc compensator n s vdc s1 s3 s5 s4 s2s6 pmsm speed controller mech. load encoder figure 1. the proposed pmsm-drive system 2. modelling of a pmsm and speed controller 2.1. pmsm model the dynamic equations of a pmsm (surface mounted type) in the threephase abc domain can be represented as below [18]. dt td asas atirtv )( )()(   (1) dt td bsbs btirtv )( )()(   (2) dt td cscs ctirtv )( )()(   (3) where rs is the stator winding resistance; ia(t), ib(t) and ic(t) are the abc stator currents, respectively; vas(t), vbs(t) and vcs(t) are the abc stator voltages, respectively and ψa(t), ψb(t) and ψc(t) are the abc stator fluxes, respectively. however, the stator fluxes are the resultant of the flux produces from stator windings and the flux of rotor permanent magnets. thus, stator fluxes can be presented in the rotating-reference frame as follows:                            )3/2sin( )3/2sin( )sin( )()( ,,,,     r r r mcba sl sl sl cba ti lmm mlm mml t (4) )( )( )()( tb dt td jtt mmle    (5) where lsl and m are the self-inductance and the mutual-inductance of the stator windings, respectively; λm is a permanent magnetic flux of magnets on the rotor; θr is the electrical position of the rotor; jm is the rotor moment of inertia; bm is the friction coefficient; te is electromagnetic torque; tl is load torque; ωe is the electrical angular velocity; ω(t) is rotor speed. the purpose of using a three-phase abc model is to optimally design an rlc compensator for depressing thd of input line current as minimum as possible and consequently reducing the torque-ripple. to the design an rlc compensator for an ac-drive system, the phasor diagram of a pmsm can be represented as an rle series circuit in fig. 2. the total stator impedance zs includes rs and ls (where ls is the equivalent stator inductance); rotor back-emf (e) is equivalent to (λm ωr), which varies with rotor speeds. rs ls vmotor ia e=pm r figure 2. an equivalent circuit of a pmsm per phase 2.2. speed controller in dq frame in this paper, the standard vector control based on dq frame is considered for adjusting the rotor speed of the pmsm in order to investigate the relationship between the change of rotor speed and the ripples in torque. the basic dq equations are illustrated as follows:[6,19] qqe d ddsd il dt di lirv  (6) medde q qqsq il dt di lirv   (7)  qdqdqme iilli p )( 2 3   (8) qme ipt 5.1 (9) where the parameters and variables of above equations can be represented as follows: p is the number of pole-pairs; ld and lq are the d-axis and qaxis stator inductances, respectively; id and iq are the d-axis and q-axis domain stator currents, respectively. fig. 3 illustrates the block diagram of the speed controller used with the proposed rlc compensator. it is bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 19 based vector speed control strategy. the measured three-phase line currents are compared with the three-phase reference line currents, then adjusted by a pi controller for generating pulses to the inverter via a logical controller. the outer loop of speed controller (i.e. the difference between the reference speed r * and the measured rotor speed r) is designed to generate the reference current controller. it can be seen that the reference d-axis current is considered zero in order to reduce the copper losses. also, the electromagnetic torque will include only the effective torque ( 3 2 m q p i ) and the reluctance torque ( 3 2 ( ) d q d q p l l i i ) will be zero. . 1 . s inverse park transform pi logical controller clark transform pwm generator pwm r r r* id* = 0 iq* 3ph line currents 3ph ref. line currents + + figure 3. block diagram of the speed controller 3. design and analysis of an rlc compensator 3.1. design of rlc compensator procedures the main objective of this paper is designing an rlc compensator for a pmsm-drive system. in [20] and [21], an rlc compensator has been proposed for decreasing thd of input current and rf of electromagnetic torque. the rlc compensator provides complexities in selecting its parameters that ensure stable operation of a pmsm-drive system under the variations of rotor speed and load. basically, an rlc compensator is essential for mitigation a range of frequencies (from the lower cut-off frequency ω1 to the upper cut-off frequency ω2). the bandwidth b of the rlc compensator must be related to the high switching frequency of the inverter in order to compensate the input reactive power delivered to pmsm. the function of the rlc compensator is to reduce the high order harmonics of the input current at the switching frequency of the voltage source inverter (vsi), fig. 4 shows the equivalent single line diagram of the proposed rlc compensator considering the higher terms of harmonics in the line current of pmsm. where vinv is the voltage supplied by a vsi; iinv is the input line current including harmonics; lc is inductor and capacitor in series; irn is the current n-harmonic components after compensation; imn is the motor line current with reduced n-harmonic components and vm phase voltage of the motor. it is worth noting that design of the proposed rlc compensator is based on selecting its resonant frequency less than 50% of the switching frequency of the vsi in order to avoid resonance drawbacks.[22]. the optimal values of r, l, and c of the compensator are calculated to obtain the best performance [23, 24]. it is worth noting that the reactive power q is calculated at full-load. 1 2 f f f l r b c  (10) 1 2 1 f f l c  (11) 2 1 2 f q c v   (12) vinv iinv imn irn vmr lc figure 4. an equivalent single line diagram of the proposed rlc compensator 3.2. analysis of the proposed rlc compensator the equivalent circuit of rlc compensator connected with a pmsm is shown in fig. 5. the above equivalent circuit can be simplified using the star-delta conversion method; the new delta impedances are shown in eqs.(13-15). 2 1221 13 z zrrzzz z ff   (13) f ff r zrrzzz z 122112   (14) 1 1221 23 z zrrzzz z ff   (15) where f f sc slz 1 1  and ss slrz 2 rf lf cf rs ls vinv vmotor pmsm ia1 2 3 e=lpm wr rlc compensator z1 z2 figure 5. an equivalent circuit of a pmsm with an rlc compensator per phase the entire transfer function of a pmsm connected with an rlc compensator is obtained as follows: 23 12 23 inv v e z z z    (16) 23 12 23 v inv ze tf v z z     (17) by substituting the amount of z1 and z2 in eq.(15) and simplifying the new form to be as follows: 1 2 2 23 s s n n n z r sl     (18) where 1 1 ( ) f f f n r sl sc   ; 2 ( )f s sn r r sl  and 3 1 ( )( ) f s s f n sl r sl sc    20 bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 1 2 2 23 2 f s f s n n n z s c l sc r      and 1 2 2 12 f f n n n z sc r    then: 1 2 2 2 1 2 2 1 2 2 2 f s f s v f f f s f s n n n s c l sc r tf n n n n n n sc r s c l sc r           2 ( ) f f v f s f s f f sc r tf s c l s c r c r    ( ) r f f total inv f s pm f s pm f f pm c r tf v sc l c r c r         (19) for stability analysis, the entire transfer function (i.e. the ratio of the rotor speed to the inverter voltage) is determining in eq. (20) using the parameters listed in table 1. 4 18.2 5.4 10 3.4total tf s     (20) the root locus analysis is used to verify the stability of pmsm-drive system supplied by the inverter via rlc compensator under the variation of rotor speed. fig. 6 shows the root locus of eq.(20), which includes a single pole, has the characteristics of (gain=0; pole=-6.23e-3; damping=1 and overshot=0%). it is observed that the system is stable for the optimum values of rlc compensator for 500 rpm, 1000 rpm, and 1500 rpm. figure 6. root locus of the entire transfer function 4. simulation study in this section, the implementation of pmsm-drive system is demonstrated using the simulation parameters listed in table 1, where fsw is the switching frequency of the inverter. the block diagram of the simulink model is illustrated in fig. 7. for performance verification, two scenarios (with and without rlc compensator) are studied which are: (i) at a fixed load and (ii) a step-change in load; under the variation of rotor speed (500-1500) rpm. table 1. parameters of the proposed drive-system pmsm (surfaced mounted type) parameters[25] rs stator winding resistance 2.87 ω ld = lq stator inductances in rotary reference frame 8.5 mh m permanent magnetic flux 0.175 mwb j rotor moment of inertia 8 x10-4 kg.m2 p number of pole-pairs 2 rlc compensator design parameters fsw switching frequency 25 khz fr resonance frequency 12.5 khz ω1 lower cut-off frequency 1.571x10 5 rad/sec ω2 upper cut-off frequency 3.665x10 5 rad/sec q quality factor 1.1456 rf compensator resistance 50 ω lf compensator inductor 250 µh cf compensator capacitor 725 µf figure 7. block diagram of the simulation model 4.1. results at a fixed load at full-load, a simulation test and its findings are illustrated in figures (810). in figures (8-c,9-c, and 10-c), the electromagnetic torque at steadystate shows the rigid performance of the proposed rlc compensator under the change of rotor speeds (500 rpm, 1000 rpm, and 1500 rpm). it is observed that the steady-state peak-peak torque-ripple in case of without rlc compensator are (0.150 n.m), (0.154 n.m) and (1.162 n.m) for 500 rpm, 1000 rpm, and 1500 rpm respectively. while in the case of with the proposed rlc compensator are (0.045 n.m), (0.044 n.m) and (0.040 n.m) for 500 rpm, 1000 rpm, and 1500 rpm respectively. figures (8-a,9a, and 10-a) show line current waveforms without rlc compensator at 500 rpm, 1000 rpm, and 1500 rpm respectively. it is observed that distortion increased with increasing the rotor speeds and the thd are always above 5% as listed in table 2. while figures (8-b,9-b, and 10-b) show line current waveforms with the proposed rlc compensator at 500 rpm, 1000 rpm, and 1500 rpm respectively. it is clear that the waveforms are sinusoidal for all rotor speeds and the thd are always less than 1% as presented in table 2. bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 21 (a) line currents without rlc compensator (b) line currents with rlc compensator (c) electromagnetic torque comparison figure 8. simulation results at a fixed load for rotor speed 500rpm (a) line currents without rlc compensator (b) line currents with rlc compensator (c) electromagnetic torque comparison figure 9. simulation results at a fixed load for rotor speed 1000rpm 22 bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 (a) line currents without rlc compensator (b) line currents with rlc compensator (c) electromagnetic torque comparison figure 10. simulation results at a fixed load for rotor speed 1500rpm table 2. performance results for various rotor speeds rotor speed(rpm) 500 750 1000 1250 1500 torque ripple without compensator 13.34% 13.5% 14.67% 41.33% 83.33% with compensator 3.13% 3.20% 3.20% 3.06% 3.13% power ripple without compensator 11.71% 12.2% 15.91% 50.92% 82.76% with compensator 2.92% 3.26% 3.31% 3.11% 3.09% current thd without compensator 7.23% 7.29% 7.81% 10.78% 18.93% with compensator 0.77% 0.78% 0.89% 0.67% 0.77% fig. 11 shows the frequency spectrum vs. thd of the input line current at various rotor speeds with and without rlc compensator. it can be seen that thds with rlc compensator are improved in comparison with the previous case study. figure 11. total harmonic distortion of the input current at a range of rotor speed 4.2. results at a step change in load to verify the sensitivity of the proposed rlc compensator under the load change from full-load to half-load during 0.1 sec. simulation results are presented in fig. 12. it can be observed from table 3 that the percentage increase in torque ripple with respect to full-load are 1.46%, 1.67%, 1.13%, 0.33% and 1.6% at 500 rpm, 750 rpm, 1000 rpm, 1250 rpm and 1500 rpm, respectively. these percentages are always less than 2%. table 3. simulation results at a step change in load speed ripple factor full-load half-load 500 3.07% 4.53% 750 3.06% 4.73% 1000 3.13% 4.26% 1250 3.80% 4.13% 1500 2.93% 4.53% bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 23 (a) electromagnetic torque comparison at 500rpm (b) electromagnetic torque comparison at 1000rpm (c) electromagnetic torque comparison at 1500rpm figure 12. simulation results at a step-change in load 5. conclusion this paper developed an rlc compensator for a pmsm-drive system to improve its performance, i.e. minimizing the thd of the line current and ripples in electromagnetic torque. in addition, this paper reviewed the control methods and drive topologies for torque-ripple reduction. the existing control methods for torque-ripple reduction were based on improving the standard vector control using intelligent techniques, which are so sensitive with rotor speed variations. in typical methods, rlc filters have been implemented, which were suitable for fixed-speed drive systems. in this research, an rlc compensator is improved for torque-ripple reduction under a wide range of rotor speeds (500-1500) rpm. the proposed rlc compensator is optimally designed and the stability analysis is verified using the root locus method. the line current of the pmsm with the proposed rlc compensator includes less-oscillations than without rlc compensator, hence reduction of thd is observed consequently the torqueripple is improved. results have shown that in case of without rlc compensator, the maximum values of thd of line current and rf of torque are 18.93% and 83.33%, respectively. while in the case with the proposed rlc compensator the maximum values of thd and rf are 0.89% and 3.20%, respectively. references [1] m. soora, a.vandhana, v.srujana, torque ripple minimization of a bldc motor drive by using electronic commutation and speed, current controllers, international journal of engineering, business and management, 1(1) (2017) 1927. 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[18] h. fadil, d. yousfi, m.l. elhafyani, y.a. driss, a.r. nasrudin, four-switch three-phase pmsm converter with output voltage balance and dc-link voltage offset suppression, in: 2016 international conference on electrical sciences and technologies in maghreb (cistem), 2016, pp. 1-7. [19] j. wang, w.c. gan, l. qiu, a gain scheduled controller for sinusoidal ripple elimination of ac pm motor systems, in: 2007 mediterranean conference on control & automation, 2007, pp. 1-6. [20] k. hatua, a.k. jain, d. banerjee, v.t. ranganathan, active damping of output lc filter resonance for vector-controlled vsi-fed ac motor drives, ieee transactions on industrial electronics, 59(1) (2012) 334-342. [21] g. zhang, x. liu, l. mei, h. ouyang, x. deng, filter design at the output of the inverter in pmsm drives, compel the international journal for computation and mathematics in electrical and electronic engineering, 36(1) (2017) 364-377. [22] m. said-romdhane, m. naouar, i. belkhodja, e. monmasson, an improved lcl 24 bashar a. fadheel /al-qadisiyah journal for engineering sciences 12 (2019) 017–024 filter design in order to ensure stability without damping and despite large grid impedance variations, energies, 10(3) (2017) 336. [23] h. horowitz, in: chapter 6, pp. 32-60. [24] j. arrillaga, n.r. watson, power system harmonics, john wiley & sons, 2003. [25] i. yousefi, m. ghanbari, parameter estimation of permanent magnet synchronous motor using orthogonal projection and recursive least squares combinatorial algorithm, mathematical problems in engineering, 2015 (2015) 7. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 439 study the optical properties of copper oxide thin film deposited by cold spray samir h. awad riyam i. jadaan abstract: copper oxide (cuo) thin films were prepared by cold spray process using inert atmosphere (helium gas) without employing any catalyst. cuo dry powder was sprayed onto microscope glass slide by heating carrier gas at 100, 200, 300, and 400 °c ,with 30 bar gas pressure onto substrates of 300 ± 5°c at different angles 0°, 30°, 45°, then study the effect of these parameter on the structural, and optical properties of the resulted thin film. the x-ray diffraction (xrd) studies showed that the as-deposited cuo has the monoclinic structure with low strain. sem images show that the thin film has no porosity or agglomeration and deposit on the entire region. the cuo thin film exhibited a high transmittance of about (96%). key words: tco materials; optical properties; cuo; cold spray process. المرسبة بالرش الباردالرقيقة النحاس أوكسيدالخواص البصرية ألغشية دراسة ريام عماد جدعان سمير حامد عواد الخالصة م�واد أي) ب�دون اس�تخدام الهلي�ومالنحاس باستخدام طريقه الرش البارد عن طريق اس�تخدام غ�از خام�ل (غ�از أوكسيدتم ترسيب أغشية درجه مئوية بواسطة تسخين 300أرضيات زجاجية المسخنة بدرجه حرارة النحاس الجاف على أوكسيدمساعدة. حيث تم رش مسحوق ) .بع�دها ت�م دراس�ة ت�أثير ه�ذه 45, 30, 0بار بزوايا ترس�يب مختلف�ة ( 30) درجة مئوية بضغط 100,200,300,400الغاز بدرجات ( لى الخواص التركيبية والبصرية لألغشية الناتجة .حي�ث اظه�رت نت�ائج حي�ود االش�عه الس�ينيه أن االغش�يه المترس�به تمتل�ك المتغيرات ع عل�ى اي مس�امات او تك�تالت وان المس�حوق يح�وي تركيب أحادي الميل .أما صوره المجهرااللكتروني الماسح فاظهرت بان الغشاء ال %).96تلك شفافيه عاليه تصل الى (مترسب على كل االرضيه .و الغشاء يم year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 440 1introduction in recent years, the synthesis of nanostructured thin films of a semiconductor and metal oxides has attracted an increasing attention due to their excellent electronic and optical properties compared with those of the corresponding bulk materials [1]. the current challenges are to find methods to synthesis of these materials with controlled characteristics of size, phase, morphology, composition and good levels of purity to generate thin films [2,3], one of these methods is the cold spray where the worldwide interest in the cold spray technique has led to significant research effort, both in the design of equipment and methods to make it more simple and efficient [4]. this method is totally different from other coating processes because the use of low temperatures where low temperature aids in retaining the original powder chemistry and phases in the coating, with changes only due to deformation and cold-working [5]. and prevent stress generation which always induces after the significant change in the temperature [4]. also this process has another feature which is it low cost in comparison with other thermal spray method [6]. oxides of copper are known to show p-type conductivity and are attracting renewed interest as promising tco materials in the fabrication of a wide range of optoelectronic devices. nontoxic, economic and abundant availability and relatively simple formation of oxide makes copper oxide as an interesting material [7]. cuprous oxide (cu2o) and cupric oxide (cuo) are the two main semiconductor phases of copper oxide with narrow band gap [8]. compared with cu2o, cuo is more stable and more easily prepared. its band gap matches the spectrum of sunlight more closely, allowing it to absorb more sunlight. these characteristics make it more suitable for solar cell applications [9]. cuo is unique as it has a square planar coordination of copper by oxygen in the monoclinic structure. the lattice parameters of cuo are a= 4.6837a˚, b= 3.4226a˚, c= 5.1288a˚[10,11]. 2. expermental detales 2-1 thin film deposition cuo films have been produced by spraying copper oxide powder onto the microscope glass substrates (1x25x75mm3) at substrate temperature of 300°c. prior to deposition, the substrates were cleaned with acetone and ethanol alcohol, washed with de-ionized water (non-ionized) followed by a wet soft tissue [12]. the powder that used is cupric oxide (cuo) with particle size 200 mesh (78µm), origin (wenger materials for craft pottery), with purity 96%. the copper oxide powder was ground for 8 hour using ball mill type (9vs, capco test equipment ltd. uk), to obtain the desire particle size. after ground of the powder the study of particle size and particle size distribution was made through a laser diffraction particle size analyzer (type 2000 bettersize instrument ltd. ,china). the home-made cold spray apparatus was fabricated and built, as shown in (figure 1). the prepared substrates are fixed onto electric heater, the growth of copper oxide microstructures were carried out by spray of powders in an inert atmosphere (helium gas) at conditions shown in (table 1). subsequently develops a nanocrystalline layer at substrate with temperature of 300℃ [13,14]. after the deposition process, the samples were annealed in vacuum furnace (gsl-1500x mti corporation, usa) the samples were annealed at 450°c [12, 15] for 30 min at a rate of 20 °c.𝑚𝑖𝑛−1 under vacuum of 0.5 × 10−3 torr. 22 structural characterization crystal structure were investigated by means of a x-ray diffraction xrd shimadzu 6000 japan using cukα1, (λ=1.5405å, 30ma, 40 kv) in 2ө range from 20˚ to 70˚. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 441 2-3 optical transmission measurement the optical transmittance of the copper oxide films was studied in the wavelength range from (300 1100nm) at room temperature. by using uv-vis-nir spectrophotometer (type sp8001 metertech, usa). 2-3-1 the absorption coefficient (α) measurement the absorption coefficient can be define as a measure of the rate of decrease in the intensity of electromagnetic radiation (as light) as it passes through a given substance ,or it is the fraction of incident radiant energy absorbed per unit mass or thickness of an absorber [16]. it is important to calculate the absorption coefficient in order to know the nature of the electron transition, if the value of measured α is high, as (𝛼 > 104 𝑐𝑚−1) then the transition is direct, while if the value of measured α is low, as (𝛼 < 104 𝑐𝑚−1) then the transition is indirect [17], also the value of absorption coefficient refer to the ability of thin film material to absorbs the incident radiation [16]. the absorption coefficient can be determined by beer–lambert law [18]: i = iₒe−αt (1) where: i is the intensity of transmitted uv spectrum, iₒ is the intensity of uv entering the material (excluding surface reflection), α is the absorption coefficient in inverse length units, t is the thickness of the thin film [18]. since a is (𝑙𝑜𝑔 𝐼ₒ 𝐼 ) and it represent the absorption of thin film, α can be rewritten as [18]: α = 2.03 𝐴 𝑡 (2) 2-3-2 optical band gap (𝐄𝐠) measurement the optical absorption is dominated by the optical band gap (𝐸𝑔) of the semiconductor that is related to the optical absorption coefficient (α) and the incident photon energy (ℎ𝑣) by using tauc equation [18]: (𝛼ℎ𝑣) = 𝐴(ℎ𝑣 − 𝐸𝑔)𝑛 (3) where α is absorption coefficient, a is constant (independent from ν) and n the exponent that depends on the kind of optical transition (n = 1/2, 2 when the transition is direct-allowed, indirect allowed respectively). the photon energy (hν) can be calculated using [19]: 𝐸 = ℎ𝑣 = ℎ𝑐 𝜆 (4) http://en.wikipedia.org/wiki/beer%e2%80%93lambert_law year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 442 where h is plank’s constant (6.626x10−34), c is speed of light (3x108) and λ is the wavelength [20]. 2-4 surface morphology to study the surface topography and morphology of films, scanning electron microscope (sem) type (tescan vega easy probe ,cz europe ), were used. the thickness of the film was monitored using depth profiler probe (pf probe) type (angstrom sun technologies inc., usa). 3results and discussion 3-1 laser diffraction particle size analyzer for cuo powder (figure 2) show particle size distribution of the cuo powder, it is possible to observe that the differential volume has a gaussian distribution and the accumulated volume is expressed in a continuous line. the statistic of the particle size distribution can be found in (table 2) ,where it can be seen that 80% of the particles are between 1.797 µm and 19.55 µm with a mean size of 10 µm . this powder presents a size in the range of the ideal size (1-50µ) of cold spray process. also, it has a narrow size distribution (0.8-28µm), therefore the particles may present the same impact velocity, by having the same weights, so it will impact the substrate at the same velocities because they can reach the same kinetic energy. 3-2 structural properties (figure 3) shows xrd patterns for cuo thin films, deposited onto substrate in the 2θ range (20˚ -70˚). pattern indicated that there are two sharp reflection peaks (1�11) and (111) at 35.552° and 38.75° respectively and the film was polycrystalline in nature. the monoclinic structure was matched with the standards peaks (astm card file no. 00-005-0661). 3-3 optical properties 3-3-1 transmittance (figure 4) shows the relationship between the optical transmittance and wavelength of the cuo thin films deposited on the glass substrate at different deposition temperatures. the value of the optical transmission increased with increasing temperature of the deposition in the ultraviolet and visible regions because as the temperature increase the grain size increase and the grain boundary decrease (which act as a scattering center) so that the light will pass without disperse, and when the wavelength is increase at near infrared region we notice that the thin film which deposits at 400℃ has a little increase compared with other deposited thin film because increasing the deposition temperature leads to the regularity of the structure. (figure 5) shows the relationship between transmittance with wavelength of cuo thin films, deposited on the glass substrate at different deposition angles. the value of transmittance increases with increasing angle of deposition, because the light does not disperse when passed through the film. the optimum optical transmittance was found for the thin film formed on a glass substrate at (200 °c and 45°). as shown in (figures 4 and 5), an average transmission of about 96% was observed for the cuo thin in the visible regain. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 443 3-3-2 the absorption coefficient (α) (figure 6) shows the variation of absorption coefficient with the photon energy for cuo at different temperature . it can be noticed that the absorption coefficient increased with photon energy increasing . (figure 7) shows the variation of absorption coefficient with the photon energy for cuo at different angle and temperature fixed at 200℃, it is clear to see that the absorption coefficient decrease as the angle increase .from the previous (figures 6 and 7) it can be concluded that the thin film has two type of electron transition (direct , indirect). 3-3-3 energy band gab (eg) 3-3-3-1 effect of temperature variation on the energy band gab (eg) the direct allowed energy band gab (eg) can happened if the transition between the upper limited of covalent band and the lower limited of conductive band. the (figures 8, 9, 10, and 11) indicate that the energy gab affects with the deposition temperature where the energy band gab (eg) value is found to be (2.35 ev –1.99 ev). where at 100℃ we notice that the eg is (2.35 ev), 200℃ (2.349 ev) , 300℃ (2.3 ev) ,and 400℃ (1.99 ev). this decrease in eg value because the decrease in localize state inside the energy band gab which may found because defect in the structure. the indirect allowed energy band gab (eg) can happened if the transition in places near the direct allowed. the coming (figures 12 ,13 ,14 ,and 15) indicate that the energy gab affects with the deposition temperature where the energy band gab (eg) value is found to be (1.25 ev – 1.12 ev) where at 100℃ we notice that the eg is (1.25 ev), 200℃ (1.18 ev) , 300℃ (1.2 ev) ,and 400℃ (1.12 ev), this decrease in eg value because decrease in localize state inside the energy band gab which may found because defect in the structure. 3-3-3-2 effect of angle variation on the energy band gab (eg) the (figures 16 ,17 ,and 18), indicate that the energy gab effects with the deposition temperature where the energy band gab (eg) value is found to be (2.349 ev –2.46 ev). where at 0˚ we notice that the energy band gab (eg) is (2.349 ev), 30˚ (2.4 ev) ,and 45˚ (2.46 ev),there is an increase in the energy band gab value. the coming (figures 19, 20, and 21), indicate that the energy gab affects with the deposition temperature where the energy band gab (eg) value is found to be (1.18 ev -1.55 ev). where at 0˚ we notice that the energy band gab (eg) is (1.18 ev), 30˚ (1.51 ev) ,and 45˚ (1.55 ev), there is an increase in the energy band gab value. the calculated band gab are collected in (table 3), to show the variation of band gab with deposition temperature and the deposition angle in easy way. 3-4 surface properties (figures 22) shows image of sem for prepared cuo thin films. it is clear that the cuo thin films have distributed over the entire area with no porosity or agglomeration. the thin film thickness is 100 nm. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 444 4conclusions 1-copper oxide thin films crystals with a monoclinic structure, were deposited by cold spray process and no template or catalyst was used. 2-the xrd results of the thin films crystals found that the thin films are consistent with the structure of monoclinic. 3-the optical transmittance for cuo thin film increased with increasing temperature of the deposition in the ultraviolet region and visible light with an average visible transmittance 96%, also it increased with increasing angle of the deposition because the deposition efficiency increase. 4the absorption coefficient increase with photon energy, also it is notice that the thin film behave two type of electron transition (direct , indirect ). the value of calculate energy gab is in the range of cuo. 5the obtain copper oxide produce in this work consider to be a (tco) transmittance conductive oxide, and all those result make copper oxide suitable material as windows for solar cell. 5references [1] i. bobowska , p. wojciechowski "synthesis of nanostructures of copper compounds and their hybridisation with titanate nanosheets" journal of crystal growth ,no.312 685–691(2010). [2] m. mukundan," phase control in the synthesis of yttrium oxide nano and micro-particles by flame spray pyrolysis", m.sc. thesis, texas a&m university, august 2007. [3] r. kavitha, s.r. hegde, vikram jayaram," oxide films by combustion pyrolysis of solution precursors", materials science and engineering, a359, 18-23(2003). [4] maria manuel fernandes barbosa, "cold spray deposition of titanium onto aluminium substrates" msc. thesis ,university of porto , portugal. [5] r. ghelichi , s. bagherifard , m. guagliano , m. verani "numerical simulation of cold spray coating" surface & coatings technology, no. 205 ,5294–5301(2011). [6] m. grujicic , v. sellappan, l. mears, x. xuan, norbert seyr, marc erdmann, jochen holzleitner " selection of the spraying technologies for over-coating of metal-stampings with thermo-plastics for use in direct-adhesion polymer metal hybrid load-bearing components" journal of material processing technique, no198, 300–312 (2008). [7] v. figueiredo, e. elangovan , g. gonḉalves , p. barquinha , l. pereira, n. franco, e. alves , r. martins , e. fortunato " effect of post-annealing on the properties of copper oxide thin films obtained from the oxidation of evaporated metallic copper" applied surface science no. 254, 3949–3954(2008). year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 445 [8] muslem f. jawad , raid a. ismail , khaled z. yahea "preparation of nanocrystalline cu2o thin film by pulsed laser deposition" j mater sciences: mater electron no 22 ,1244–1247 (2011). [9] fei gao, xiao-jing liu, jun-shan zhang, mei-zhou song, and ning li "photovoltaic properties of the p-cuo/n-si heterojunction prepared through reactive magnetron sputtering" j. appl. phys. 111, 084507 (2012). [10] p a korzhavyi, b johansson" literature review on the properties of cuprous oxide cu2o and the process of copper oxidation" technical report tr-11-08(2011). [11] b. k. meyer, a. polity, d. reppin, m. becker, p. hering, p. j. klar, th. sander, c. reindl, j. benz, m. eickhoff, c. heiliger, m. heinemann, j. bläsing, a. krost, s. shokovets, c. müller, and c. ronning "binary copper oxide semiconductors: from materials towards devices" phys. status solidi b 249, no. 8, 1487–1509 (2012). [12] mohd rafie johan, mohd shahadan mohd suan, nor liza hawari, hee ay ching "annealing effects on the properties of copper oxide thin films prepared by chemical deposition" international journal of electrochemical science, no. 6, 6094 – 6104 (2011). [13] iqbal singh, r.k. bedi "studies and correlation among the structural, electrical and gas response properties of aerosol spray deposited self assembled nanocrystalline cuo" applied surface science no. 257, 7592–7599(2011). [14] issam m. ibrahim, muhammad o. salman, ahmed s. ahmed "electrical behavior and optical properties of copper oxide thin films" baghdad science journal vol.8(2)2011. [15] v. figueiredo, e. elangovan , g. gonḉalves , p. barquinha , l. pereira, n. franco, e. alves , r. martins , e. fortunato " effect of post-annealing on the properties of copper oxide thin films obtained from the oxidation of evaporated metallic copper" applied surface science no. 254, 3949–3954(2008). أ.م صبرية عليوي ضبع , د.فاتن شكور زين العابدين , د.انتصار هاتو هاشم " دراسة تأثير التلدين على الثواب�ت البص�رية [16] .journal of college of education, no.1 ,2008المشوبة باالنديوم" cuoألغشية [17] g. busch and h. schade, "lectures on solid state physics", pergaman press, london, (1976). المحض�رة بطريق�ة ال�رش الكيمي�ائي cuo لمي�اء خض�ير عب�اس " دراس�ة ت�أثير الس�مك عل�ى الخ�واص البص�رية ألغش�ية [18] .2006) 1( 3جلد الحراري " مجلة أم سلمة للعلوم الم [19] mohd rafie johan, mohd shahadan mohd suan, nor liza hawari, hee ay ching "annealing effects on the properties of copper oxide thin films prepared by chemical deposition " international journal of electrochemical science, 6 (2011) 6094 – 6104. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 446 table (1): typical range of parameters for cold spray process. range parameters helium gas (he). operation gases 300 [13,14] substrate temperature(℃) 30 gas pressure (bar),without catalyst 100, 200, 300, 400 gas temperature (℃) 40 [4] spray distance (mm) 3 power consumption(for heat gas) (kw) 0.3 powder feed rate ( g/s) 0, 30, 45 deposition angles (°) .table (2): statistics of the particle size distribution of the cuo powder. parameters result mean particle size 10 µm diameter correspondent to 10% accumulated volume 1.797 µm diameter correspondent to 50% accumulated volume 8.263 µm diameter correspondent to 90% accumulated volume 19.55 µm table (3): optical band gap (eg) values for copper oxide thin films. parameter direct-allowed energy gab (ev) indirect-allowed energy gab (ev) 100℃ 2.35 1.25 200℃ 2.349 1.18 300℃ 2.3 1.2 400℃ 1.99 1.12 0˚ 2.349 1.18 30˚ 2.4 1.51 45˚ 2.4 1.55 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 447 figure (1): schematic diagram of a cold spray system. figure (2): particle size distribution of the cuo powder figure (3): the xrd patterns of the cuo thin films. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 448 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 449 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 450 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 451 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 452 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 453 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 454 figure (22): sem image of cuo thin film onto glass substrate at deposition temperature 200°c. the geometrical analysis accuracy for parallel robotic mechanism al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 331 effect of friction forces in robotic mechanism joints on the dynamic analysis dr. hassan m. alwan mechanical engineering department, university of technology received 16 june 2014 accepted 1 september 2014 abstract dynamic analysis of parallel robotic mechanisms plays a vital role in the design and control of such robotic mechanisms. to simplify the dynamic analysis formulation, many researches had been done assuming the robotic mechanism joints as ideal joints (without friction). this paper represents a novel mathematical model for evaluation of friction forces, torques acting in the spherical, prismatic joints of parallel robotic mechanism and their effect on the dynamic formulation of any parallel robotic mechanism. the aim of this paper is to obtain a new mathematical formulation for evaluation of the dynamic analysis in non – ideal robotic mechanism. the results show that the friction forces and torques acting on the robotic mechanism joints have actual effects on the actuators to implement the same tasks. the actuators forces shall be increased about ten percentages than the power of the actuators in case of ideal robotic joints keyword: parallel robotics mechanisms, dynamic analysis, friction forces, gough – stewart manipulators. تاثير قوى االحتكاك في مفاصل منظومة الروبوت على الحسابات الديناميكية الخالصة يرا في تصميم الروبوت وحسابات منظومة ان الحسابات الديناميكية الي منظومة روبوت متوازي تلعب دورا كب تات تم انجاز السيطرة لهكذا نوع من الروبوتات. لغرض تبسيط معادالت الحسابات الديناميكية لهذه الروبو مجموعة من االبحاث مع االخذ باالفتراض هو ان مفاصل هذه الروبوتات ذات طبيعة مثالية )بدون قوى احتكاك(. هذا البحث يستعرض طريقة رياضية جديدة لحساب قوى االحتكاك وعزوم االحتكاك التي تؤثر في وم على الحسابات الديناميكية للروبوت ى والعزوالمستقيمة وحساب تاثير هذه القو مفاصل الروبوت الكروية بصورة عامة. يذ نفس المهمات للروبوت . ان القوى التي بينت النتائج بان لقوى االحتكاك تاثير فعلي على المحركات لتنف استخدام مفاصل مثالية للروبوت. المحركات يجب ان تزداد حوالي عشرة بالمائة عنها في حالة يسلطها للحسابات الديناميكية للروبوت ذو المفاصل غير المثالية )ذات هو اليجاد معادلة رياضية ان هدف هذا البحث االحتكاك(. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 332 1. introduction there are two types of robotic systems mechanisms, the first type is named open kinematics chain mechanisms and the second is the closed kinematics chain mechanisms. dynamic analysis of any robotic mechanisms means the evaluation of the actuators forces (controlled forces) which are necessary to implement its task. in this paper the gough – stewart robotic mechanism is chosen (fig.1). it is the famous kind of the closed kinematics chain mechanisms. it consists of a set of serial links each connected to a fixed base from one end, and connected to a common moving platform (or end effecter) on the other end. in general, gough-stewart platform manipulator is a six degree of freedom with two main bodies [3]. the fixed body is called the base, while another body is regarded as movable and is called the moving plate (platform). in this paper, to solve the dynamic of the robotic mechanism, every linkage (i) of its linkages (legs) will be divided into five parts as shown in fig.2. zone (0i): global coordinate base. zone (1i): local coordinate (moving platform) zone (2i): the linkage body part located between spherical joint on the moving platform and the prismatic joint zone (3i): the prismatic joint zone (4i): the linkage body part located between spherical joint on the base and the prismatic joint. in this paper, the motivation is to derive a mathematical formulation for the evaluation of the actuators forces in case of non ideal mechanism joints. the values will be evaluated by obtaining a novel formulation and using math cad program. 2. problem formulation forces acting on the linkage (i) of the proposed robotic mechanism will be defined as shown in the fig.3 and fig.4.as follow: : reactions and moment acting on the spherical joint (with finger) connected the linkage with the base. : reactions acting on the spherical joint connected the linkage with the moving platform. : inertia forces and moments of the (2i) part of the robotic mechanism linkage : reactions and inertia force and moment acting on the prismatic joint (3i), : is the actuator (controlled force) acting on this linkage of mechanism. : inertia forces and moments of the (4i) part of the robotic mechanism linkage air : the coordinate vector of the spherical joints connected the fixed base with the legs of the manipulator (in the global coordinate system); bi r : the coordinate vector of the spherical with finger joints connected the moving platform with the legs of the manipulator (in the local coordinate system); o r : the coordinate vector of the moving platform center (in the global coordinate system); ol t : the matrix of the coordinate transformation from the local coordinate system to the global coordinate system; al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 i s : prismatic joints displacement (legs extension). the robotic mechanism will be divided into six structures; each linkage (leg) of the manipulator mechanism is treated as an independent substructure. the forces equilibrium of the (i) linkage will be divided into two bodies. the first body is the linkage part located between the mechanism base (0i) and the prismatic joint (3i) as in fig.3, the second body is the linkage part which located between the prismatic joint (3i) and the moving platform (2i) as in fig.4. the equilibrium equation for the first body can be written: ∑ , ∑ , ∑ , ∑ (1) ( ) ( ) ∑ ( ) ( ) ∑ the equilibrium equation for the second body will similarly be written as follow: ∑ , ∑ , ∑ , ∑ (2) ( ) ( ) ∑ ( ) ( ) ∑ , where: | | | | | | | | c2i , c4i are the mass centers of the bodies 2i and 4i respectively. 3. robotic mechanism joints friction forces friction force in the spherical joint (ai) between the moving platform and the linkage part (2i) can be determined as a friction moment. this moment is acting proportional with the main reaction vector in al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 334 the joint and in the opposite direction of the relative angular velocity of the moving platform (1i) to the linkage (i). this moment can be written as follow: √( ) | | (3) where: kai : coefficient of friction in the joint bi : projection of the relative angular velocity vector of the moving platform to the linkage. similarly, the friction moment in the spherical joint (bi) in the mechanism base can be written as follow: √( ) | | (4) where: kbi : coefficient of friction in the joint ai : projection of the angular velocity vector of the linkage according to the base. friction force in the prismatic joint will be acted along the linkage length and in the opposite direction of the joint velocity( )̇ . it can be written as follow: √(( ) ( ) ) ̇ | ̇| ̇ (5) where: ki: coefficient of the friction in the prismatic joint (3i) ̇ : linear velocity of the prismatic joint along the linkage length. in additional there are other forces acting on the linkage f. the forces consist from gravity force of the mechanism elements, working force and inertia forces [1]. ( ) 4. controlled forces evaluation the equations (1) & (2) are in the local coordinates systems in which z-axis is parallel to the linkage length. in case of transferring these equations to the global coordinate system, the coordinate’s transformation matrix t shall be used. when the linkage (i) is assumed in the position of angles αi and βi with the global coordinate system, the matrix t will be as follow: ( ) , where: , , , al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 335 , , , , from the mathematical analysis it can be used √ , √ √ | | when the linkage (i) will move to another position with the angles and , the little angular displacement vector of the linkage (i) can be written as follow: transformation of the little angular displacement vector to the global coordinate system will be result: in other words, the little angular displacement vector equal to: ( ) from this vector, the angular velocity vector of the linkage (i) in the global coordinate system can be obtained: ( ̇ ̇ ̇ ) to use the virtual work equation, the robotic mechanism shall implement little linear and angular displacements for any force and moment. these displacements will be as follow: little linear displacement for the controlled forces ( )and friction force in the prismatic joint ( ) is . the little linear and angular displacement for the external forces ( )and the forces in the spherical joint of the moving platform ( ) is . also the little angular displacement for the forces in the spherical joint of the base ( ) is . now, the virtual work on the robotic mechanism (all linkages) can be derived as in the relation below: ( ∑ ) ( ) ∑ (6) [( ) ( )] [ ∑ ] ∑ ( ) (7) where: al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 336 : controlled forces in actuators : all the forces and moments acting in spherical joints : all the forces and moments acting in spherical joints : all external forces and moments acting on the moving platform ( ) , ( ) 5. example of evaluation and discussion in this example a gough –stewart mechanism has been chosen with the following parameters: the base of the mechanism is 2m diameter. the global coordinate system center is located in the base center with z=0. the spherical joints located on the outer diameter of the base with the angle with reference to the x-axis. the moving platform of the mechanism is 1.6m diameter. the local coordinate system center is located in the moving platform center with z=0. the spherical joints located on the outer diameter of the moving platform with the angle with reference to the x-axis of the local coordinate system. moving platform mass = 15 kg the external forces and moments acting on the moving platform: ( ) the inertia tensor is a unit matrix of 0.1 kg.m 2 the linear and angular displacement of the moving platform with 0.1m/s 2 and 0.01 degree / s 2 in all directions. prismatic joints linear velocity is 0.02m/s for each linkage. coefficient of friction is 0.03 in each prismatic and spherical joint. the moving platform center implement a track begins from point 1 and finished in point 6. the track divided into six segments 1,2,3,4,5,6. it was assumed that the moving platform center stopped in each point of the six points. the actuators forces needed to implement the track have been evaluated in each point of the six points for each linkage. the results are as in shown (fig.5 a,b,c,d,e,f) in curve.1 for the mechanism without friction and curve.2. the results show that the friction forces and torques acting on the robotic mechanism joints have actual effects on the actuators to implement the same tasks. the actuators forces shall be increased about ten percentages than the forces of the actuators in case of ideal robotic joints 6. conclusion in this paper, a novel method had been used to derive a mathematical formulation for the dynamic analysis of a parallel robotic mechanism. the dynamic analysis is proposed based on the virtual work method. the innovation in this paper is that, the joints of the robotic mechanism are no-ideal (with the friction forces evaluation). it has been proved that all the controlled forces can be evaluated and compared with the same forces when the joints without friction. 7. references al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 337 [1]. carricato, m., and parenti-castelli, “singularity-free fully-isotropic translational parallel mechanisms”. international journal of robotics research vol21, 2002 p:161–174 [2]. hassan m. alwan, muhsin n. hamza, “dynamic analysis of gough stewart manipulator”, eng. & tech. journal vol.28 no.16, 2010 p.5246-5255 [3]. hassan m. alwan, hayder sadah, “singularity analysis of parallel robot with six dof of six legseng. & tech. journal vol.32 no.4, 2014 p.960-972 [4]. j.c. trinkle, r. james milgram, “complete path planning for closed kinematicchains with spherical joint”, the international journal of robotics research, september 2002. [5]. j. cort_es, t. sim_eon, j.p. laumond, “a random loop generator for planning the motions of closed kinematic chains using prm methods”, journal of mechanical design, january 2007. [6]. jiang hong zhou, tong zhi zhong, and he jine feng: “dynamic isotropic design of a class of gough – stewart parallel manipulators”. journal of mechanisms and machine theory 46, 2011, p358 – 374 [7]. jiegao wang and clement m, gosselin . “a new approach for the dynamics analysis of parallel 1manipulators”. journal of multi-body system dynamics, vol.2, 1998, p.317-334 [8]. jonas ballani and lars grasedyck: “a projection method to solve linear system in tensor format”, journal of numerical linear algebra with applications, vol. 20, 2013, p: 27-43 [9]. li, q. c., and huang, z., ‘‘mobility analysis of a novel 3-5r parallelmechanism family,’’ asme j. mech. des.,vol 126 , 2004 , p. 79–82. [10]. mats isaksson, tong torgny brogardh, and matthew watson: “the octahedral hexarot, a novel 6 – dof parallel manipulator”. journal of mechanisms and machine theory 455, 2012, p91 – 102 [11]. r. bohlin and l. kavraki. “path planning using lazy prm”. in ieee international conference on robotics and automation, 200, p. 521-538 [12]. stefan staicu : “dynamic of 6 – 6 parallel manipulator,” journal of robotics and computer – integrated manufacturing, vol. 27, 2011, p.212 220 al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 338 fig ure 1: gough – stewart mechanism figure 2: robotic mechanism linkage (i) al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 339 figure 3: first linkage body figure 4: second linkage body al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 340 figure 5 a figure 5 b -5 0 5 10 15 20 0 2 4 6 force kn point controlled force on linkage (1) without friction -5 0 5 10 15 20 0 1 2 3 4 5 6 force kn point controlled force on linkage (2) without friction with friction al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 341 figure 5 c figure 5 d -6 -4 -2 0 2 4 6 8 0 2 4 6 force kn point controlled force on linkage (3) without friction with friction -8 -6 -4 -2 0 2 4 6 8 10 12 14 0 1 2 3 4 5 6 force kn point controlled force on linkage (4) without friction al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 342 figure 5 e figure 5 f -2 0 2 4 6 8 10 0 2 4 6 force kn point controlled force on linkage (5) without friction with friction -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 0 1 2 3 4 5 6 force kn point controlled force on linkage (6) without friction with friction al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 513 particle swarm optimization based optimum pid controller for governor system of synchronous generator helen j. jawad abstract: this paper presents a particle swarm optimization (pso) method for determining the optimal proportional – integral-derivative (pid) controller parameters for governor control of a synchronous generator .the proposed approach has superior features, including easy implementation, stable convergence characteristic and good computational efficiency. the synchronous generator is modeled and the pso algorithm is implemented in simulink of matlab. the simulation results demonstrates the effectiveness of the designed system in terms of reduced settling time, peak overshoot and oscillations of frequency devaition. the results are compared with traditional trial and error tuning of the pid controller. which gives in the pso-pid controller: maximum positive overshoot of frequency deviation =0 and negative overshoot of frequency deviation =-0.042, settling time= 7sec. whereas, in conventional trial and error tuning: maximum positive overshoot of frequency deviation =0.002 and negative overshoot of frequency deviation =-0.03, settling time= 11sec. keywords: pid controller, particle swarm optimization, synchronous generator ,governor system. مسيطر التناسقي التكاملي التفاضلي لاألسناد األفضل الحركة المثلى ألسراب الجزيئات لد المتزامنولمل الحاكمللسيطرة على نظام الخالصة: التكاملي المسيطر التناسقي تحديد معامالتالحركة المثلى السراب الجزيئات في طريقة هذا البحثيقدم تضمن متفوقة وهذه الطريقة المقترحة لها ميزات .للمولد المتزامن اكمالحرة على نظام طالتفاضلي للسي ان المولد المتزامن تم تمثيله .جيدةالحسابية كفاءة وال خصائص تقارب مستقرة ,بسهولة التطبيق ونتائج matlab في في برنامج المحاكاة وخوارزمية الحركة المثلى السراب الجزيئات تم تنفيذه وتذبذبات overshoot , تجاوز وقت االستقرار تقليل فعالية النظام المصمم من ناحيةيعرض المحاكاة حيث كانت التجربة والخطأ .والنتائج تم مقارنتها مع الطريقة التقليدية . deviationالمشتق تردد ال =شتقللتردد الم الموجب تجاوزاالطالق االقصىالجزيئات :النتائج في طريقة الحركة المثلى لالسراب ثانية اما في الطريقة التقليدية7 =وزمن االستقرار0.042= للتردد المشتق السالبتجاوزاالطالق و 0 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 513 السالبتجاوزاالطالق و 0.002للتردد المشتق= الموجب تجاوز االطالق االقصى التجربة والخطأ: .ثانية =11وزمن االستقرار 0.03= للتردد المشتق 1. introduction: the pid (proportional-integral-derivative) control is one of the earliest control strategies. it has been widely used in the industrial control fields. its widespread acceptability can be recognized by: the familiarity with which it is perceived amongst researchers and practitioners within the control community, simple structure and effectiveness of algorithm, relative ease and high speed of adjustment with minimal down-time and wide range of applications where its reliability and robustness produces excellent control performances. however, successful applications of pid controllers require the satisfactory tuning of three parameters which are proportional gain (kp), integral time constant (ki), and derivative time constant (kd) according to the dynamics of the process. unfortunately, it has been quite difficult to tune properly the gains of pid controllers because many industrial plants are often burdened with problems such as high order, time delays, and nonlinearities [1] . traditionally, these parameters are determined by a trial and error approach. manual tuning of pid controller is very tedious, time consuming and laborious to implement, especially where the performance of the controller mainly depends on the experiences of design engineers. in recent years, many tuning methods have been proposed to reduce the time consumption on determining the three controller parameters. the most well known tuning method is the ziegler-nichols tuning formula ; it determines suitable parameters by observing a gain and a frequency on which the plant becomes oscillatory. considering the limitations of the ziegler-nichols method and some empirical techniques in raising the performance of pid controller, recently artificial intelligence techniques such as fuzzy logic , fuzzy neural network , and some stochastic search and optimization algorithms such as simulated annealing , genetic algorithm, particle swarm optimization approach , immune algorithm , and ant colony optimization have been applied to improve the performances of pid controllers [2]. in this paper the objective is to find and implement the best pid controller parameters that realize efficient control of speed and frequency. the model of the governor of single area power system is designed using simulink in matlab. the pso algorithm is developed to find the optimum proportional, integral and derivative gains of the controller. these values of pid gains are sent to workspace and shared with the simulink model for simulation under different loads. 2. modeling and simulation of synchronous machine: the overall accuracy of the power system stability is primarily decided by how correctly the synchronous generators within the system are modeled. the proposed simulation model is developed as a fourth order machine time constants in order to improve frequency deviation responses [3]. with proper modeling of the synchronous machine in the power system, a better understanding of how the machine reacts under al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 513 sudden large disturbances during transient conditions can be achieved, and hence a better power system governor controllers of the synchronous generator can be designed . the used synchronous generator name plate is :3-ph sg, 380 v., 5 kw, 4 poles, 50 hz. the values of the constants required for turbine and governor system is shown in table (1). some assumptions were taken into consideration and made prior to the design of the simulation model, these assumptions are: -the sg. turbine in this model produce a constant torque with a constant speed maintained during steady state operation. -the sg. output terminals are connected to infinite bus bar that has various load changes. only basic and linear models of the power system components will be used. -all the time constants of the sg. which are used in this model of all components are assumed to be the optimum time constants extracted based on the values given in walton[3]. the stability of a sg. depends on the inertia constant and the angular momentum. the rotational inertia equations describe the effect of unbalance between electromagnetic torque and mechanical torque of individual machines. by having small perturbation and small deviation in speed, the swing equation becomes [4]: dω / dt = (1/2h) (pm pe) (1) then dω / dt = d²δ / dt h = inertia constant  pm = change in mechanical power pe = change in electrical power ω = change in speed (elec. rad/sec) δ = rotor angle (rad.) using laplace transformation, equation (1) becomes : dδ / dtω(s) = (1/2hs) [pm(s)pe(s)] (2) a more appropriate way to describe the swing equation is to include a damping factor that is not accounted for in the calculation of electrical power pe. therefore, a term proportional to speed deviation should be included. the speed load characteristic of a composite load describing such issue is approximated by [5]: δpe=δpl+ kd δω (3) where kd is the damping factor or coefficient in per unit power divided by per unit frequency. kdω is the frequencysensitive load change and δpl is the non frequency-sensitive load change. figure (1) presents a block diagram representation of a load change derived from the swing equation with the aid of equation (3) or: δω(s) = [δpm(s) δpl (s)] [1/(2hs) .(4) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 513 figure (2) represents a simplified block diagram of the governor and avr of the synchronous generator with the two feedback quantities ( voltage and frequency ). the following proposed models are needed to study the effect of using the pid controllers and pso-pid controller which represent on the fourth order model of synchronous generator for frequency deviation stability control and how this stability have been enhanced. 2.1 generator model a fourth order model of the sg. consists of a generator gain plus four pairs of polezero time constants can be modeled. in terms of expressing this as a transfer function, then the following equation is given [6]: (5) there are two ways in matlab simulink to design the machine model, these are: 1. using power system block set which is a set of ready-made [7]. 2.using blocks of transfer functions of the machine to manipulate the design model. however, using blocks of the transfer function to represent the components in the power system is capable of having higher order machine time constants as inputs. this can be achieved by the illustration shown in figure (3) [8,9]. where: g k = gain of the generator, z t = time constant of the zero, p t = time constant of the pole, f v = field voltage of the sg, tv = terminal voltage of the sg. 2.2 exciter model the most basic form of expressing the exciter model can be represented by a gain e k and a single time constant e t : f v (s) / vr (s) = e k / (1 + s e t ) (6) vr = the output voltage of the regulator (avr), f v = field voltage . the excitation system amplifier is represented similarly by a gain ka and a time constant ta. the transfer function of the amplifier is: vr(s)/ δve(s)=ka / (1+ sta) (7) where: δve = voltage error = reference voltage (vref ) output voltage of the sensor(vs). 2.3 sensor model the terminal voltage of the sg. is being fed back by using a potential transformer that is connected to the bridge rectifiers. the sensor is also being modeled, likewise as the exciter: )1()1()1()1( )1()1()1()1( )(/)( 4321 4321 pppp zzzz gft stststst stststst ksvsv    al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 513 vs(s) / vt(s) = kr / (1 + str) (8) vs = output voltage of the sensor, kr and tr are the gain and time constant of the sensor . 2.4 automatic voltage regulator (avr) mode in most modern systems, the avr is a controller that senses the generator output voltage then initiates corrective action by changing the exciter control in the desired direction [10]. a simple avr is created with a 1 st order model of sg as shown in the figure (4). from this block diagram, the closed loop transfer function of a 1st order relating the generator terminal voltage vt(s) to the reference voltage vref(s) can be written as follow: vt(s) / vref(s) = geargea rgea kkkstststst stkkk   )1)(1)(1)(1( )1( 1 (9) 2.5 turbine model the simplest form of model for a non-reheat steam turbine can be approximated by using a single time constant tt. the model for turbine associates the changes in mechanical power pm with the changes in steam valve position €v is given as: g (s) = pm(s) €v(s) = 1 / 1 + stt ( 10) 2.6 governor model the speed governor mechanism works as a comparator to determine the difference between the reference set power pref and the power (1/r)asshown in figure (5). the speed governor output sg is therefore: sg (s) = pref (s) – (1/ r )(s) (11) where r represents the drop. speed governor output sg is being converted to steam valve position €v through the hydraulic amplifier. assuming a linearized model with a single time constant tg: €v(s) = (1 / (1 + s tg)) sg(s) (12) the final simulation model for a 4th order sg without controller for 0.6 p.u load change can be developed in "matlab" as shown in figure (6) and the output performance of the system can be shown in fig.(7) . its seen from figure that the response for frequency deviation(without controller oscillates for a period of 14.03 seconds before settling down to zero deviation. there is an overshoot error occurring at 1.6 seconds. the ideal response is to al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 keep the deviation (oscillation) as close to zero as possible at the minimum period of time. 3. the pid controller: it is an important matter for the stable electrical power service of the synchronous generator with a high efficiency and a fast response. until now, the analog pid controller is generally used for the governor system because of its simplicity and low cost. the governor system model controlled by the pid controller can be expressed by figure (8 ).the pid controller calculations involve three parameters that must be determined for the given process, to give the desirable output responses for the plant are : proportional gain, integral gain and derivative gain (kp, ki and kd respectively). the transfer function of the pid controller looks like the following [11] : c(s) = kp + ki / s + kd s = (kd s 2 + kp s + ki) /s (13) kp = proportional gain, ki = integral gain, and kd = derivative gain. the error signal (e) will be sent to the pid controller, and the controller computes both the derivative and the integral of this error signal. the signal (u) just past the controller is given as: u= kp.e +ki ∫e.dt + kd de/dt (14) this signal will be sent to the plant, and the new output (y) will be obtained. this new output (y) will be sent back to the sensor again to find the new error signal (e). the controller takes this new error signal and computes its derivative and its integral again. this process will continuous until the desired output achieved. in this paper, the best result can be obtained of the pid controller parameters, by using trial and error method, to achieve the frequency deviation of the non-linear synchronous generator in the governing system: kp= 0.8, ki= 0.001, and kd= 0.6. which give a transient system response to the unit step input for 0.6 p.u load change: ● max. positive overshot of frequency deviation =0.002 and negative overshot of frequency deviation =-0.03. ● settling time=11 sec. ● steady state error= 0%. the output performance of the system for 0.6 p.u load change can be shown in figure (9). 4.particle swarm optimization: pso is one of the optimization techniques first proposed by eberhart and colleagues [12, 13]. this method has been found to be robust in solving problems featuring non-linearity and non-differentiability, which is derived from the socialpsychological theory. the technique is derived from research on swarm such as fish schooling and bird flocking. in the pso algorithm, instead of using evolutionary operators such as mutation and crossover to manipulate algorithms, the population dynamics simulates a "bird flocks" behavior, where social sharing of information takes al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 521 place and individuals can profit from the discoveries and previous experience of all the other companions during the search for food. thus, each companion, called particle, in the population, which is called swarm, is assumed to " fly " in many direction over the search space in order to meet the demand fitness function [12 ,13, 14, 15]. for n-variables optimization problem a flock of particles are put into the ndimensional search space with randomly chosen velocities and positions knowing their best values, so far (pbest) and the position in the n-dimensional space [12, 13]. the velocity of each particle, adjusted accordingly to its own flying experience and the other particles flying experience. for example, the ith particle is represented, as:, (15) in n-dimensional space, the best previous position of the ith particle is recorded as: (16) the modified velocity and position of each particle can be calculated using the current velocity and distance from ( ) to ( ) as shown in the following formula [12, 13, 14, 15]: (17) (18) i=1,2,…..,n m=1,2,…..,d where; n = number of particles. d = dimension. iter. = iterations pointer. = velocity of particle no. i at iteration it. w = inertia weight factor. c1,c2 = acceleration constant. rand = random number between 0-1. = current position of particle i at iteration it. = best previous position of ith particle. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 522 = best particle among all the particles in the population. 5. implementing pso –pid controller a. fitness function: the most common performance criteria are integrated absolute error (iae), the integrated of time weight square error (itse) and integrated of square error (ise) that can be evaluated analytically in frequency domain [14, 16, and 17]. these three integral performance criteria in the frequency domain have their own advantage and disadvantage. for example, disadvantage of iae and ise criteria is that its minimization can result in a response with relatively small overshoot but a long settling time, because the ise performance criteria weights all errors equally independent of time. although, the itse performance criterion can overcome the disadvantage of ise criterion. the performance criterion formula for, iae, ise, and itse are as follows [17]: (19) (20) …… (21) in this paper, the integrated of time weight square error itse is used for evaluating the pid controller. a set of good control parameters can yield a good step response that will result in performance criteria minimization in the time domain, this performance criterion is called fitness function (ff) which can be formulated as follows [1]: (22) where: mp is maximum overshoot. ess is steady state error. ts is the settling time. tr is the rise time. is the weighting factor can set to be larger than 0.7 to reduce the overshoot and steady state error, also can be smaller than 0.7 to reduce the rise time and settling time. b. proposed pso pid controller in this paper a pso is used to find the optimal parameters of governor pid control system. fig. (10) shows the block diagram of optimal pid control for the governor system. in the proposed pso method each particle contains three members p, i al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 525 and d . it means that the search space has three dimension and particles must ‘fly’ in a three dimensional space. the flow chart of pso-pid controller is shown in fig.(11) and the system performance of pso-pid controller is shown in fig. (12). the pso algorithm was simulated and tested by tuning the various parameters like poplation size, inertia weight and acceleration factor. the optimum parameter values that achieved better solution are listed in table (2). the simulation was done using the simulink package available in matlab. the frequency deviation response is simulated using pso based pid controller, for 0.6 p.u of load change. the simulation time was set to 20 second. the frequency deviation response for a change in load of 0.6 p.u is shown in fig.(12). particle swarm optimization (pso) algorithm, parameter values are: kp =0.5, ki =0, kd =0.4, that the frequency deviation response gives by the unit step input; * max. positive overshoot of frequency deviation =0 and negative overshoot of frequency deviation =-0.042 * settling time = 7sec. * steady state error = 0%. * itse = 0.005163 6. comparison results a coparison on dynamic performances between various controllers for governor system are represented in table (3). the settling time, oscillations and overshoot are compared for a load change of 0.6 p.u. it is observed from the table that the frequency deviation responses of the 4 th order sg . model for 0.6 p.u load change without controller ,with pid controller and pso-pid controller. its seen from the table that the pso-pid controller exhibits relatively good performance with very less settling time, overshoot and transient oscillations. 7. conclusion: the quality of the power supply is determined by the constancy of frequency and voltage. minimum frequency deviation and good terminal voltage response are the characteristics of a reliable power supply. in this work a pso method is used to determine pid controller parameters is obtained through simulation of synchronous generator for governor. the results its show that the proposed controller can perform an efficient search for the optimal pid controller. by comparison with the conventional controller methods, it shows that this method have large settling time, overshoot and oscillations. hence , when pso-pid algorithms are used to control governor system, their typical characteristics show a faster and smoother response. 8. references: [1] zwe-lee gaing, “a particle swarm optimization approach for optimum design of pid controller in avr system”, ieeetransactions on energy conversion, vol.19, no.2, 2004, pp384-391. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 [2] m.pourmahmood aghababa, a.m. shotorbani and r.m.shotorbani,'' an adaptive particle swarm optimization applied to optimum controller design for avr power systems'', international journal of computer application (0975-8887) volume 11no.10, december 2010. [3] walton , a., ''characteristics of equivalent circuits of synchronous machines'', iee proc. electr. power appl., vol. 143, no. 1, pp. 31-40,january 1996. [4] ieee/cigre joint task force on stability terms and definitions, "definition and classification of power system stability", ieee transactions on power systems, vol. 19, no. 2, pp. 1387-1401, may 2004. [5] saadat, h., ''power system analysis'', mcgraw-hill inc., 1999. [6] cirstea ,m. n., dinu ,a., khor ,j. g.,cormick, m. m.,'' neural and fuzzylogic control of drives and power systems'', linacre house, jordan hill, 2002. [7] park ,j. w. , harley ,r. g.,venayagamoorthyc, g. k., jang ,g. ,'' dual heuristic programming based nonlinear optimal control for asynchronous generator'' , school of electrical and computer engineering,georgia institute of technology,usa, 2007. [8] sedaghati ,a. r., '' a pi controllerbased on gain-scheduling for synchronous generator '' , faculty of electrical engineering tafresh university, tafresh, iran, vol.14, no.2, 2006. [9] matlab user guide version 1, ''power system blockset for use with simulink'', electronic copy from http://www.mathworks.com, visited on 14 feb 2006. [10] anderson ,g., ''dynamics and control of electric power systems'' ,eth zurich press, march 2003. [11] goodwin ,g. c., graebe ,s. f. and salgado ,m. e., ''control system design'', santa maria press, valparaiso, chile, 2000. [12] b. nagaraj and n. murugananth "soft computing-based optimum design of pid controller for a position control of dc motor", mediamira science publisher, volume 51, number 1, 2010. [13] b. allaoua, b. gasbaoui, and b. merbarki "setting up pid dc motor speed control alteration parameters using particle swarm optimization strategy", leonardo electronic journal of practices and technologies, issue 14, p 19-32, 2009. [14] m. nasri, h. nezamabadi and m. maghfoori, "a pso-based optimum design of pid controller for a linear brushless dc motor", world academy of science, engineering and technology, 2007. [15] s.m.girirajkumar, deepak jayaraj and anoop.r.kishan, "pso based tuning of a pid controller for a high performance drilling machine", international journal of computer applications (0975 8887), volume 1, no. 19, 2010. [16] popov a., farag a., werner h., "tuning of a pid controller using a multi objective optimization technique applied to a neutralization plant", 44 th ieee conference on decision and control, and the european control conference, 2005. [17] lieslehto j., "pid controller tuning using evolutionary programming", american control conference, va june 25-27, 2001. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 table (1) values of the constants required for turbine and governing system (all values are in per unit) table (2) parameters of pso algorithms table (3) frequency deviation response for 0.6 p.u. load change without controller, with pid controller and with pso-pid pref kd r h tg tt  0 0.8 0.05 10 0.2 0.5 number of iterations 25 population size 20 w max. 0.3 c1 = c2 1.2 results without con. pidcon. psopid maximum positive overshoot 0.03 0.002 0 negative overshoot -0.04 -0.03 -0.042 settling time (sec.) 14.03 11 7 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 figure (1) block diagram representing a 4th order sg time constants model figure (2) block diagram of governor and avr of the sg al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 figure (3) block diagram of a load change model figure (4) block diagram of a simple avr . figure (5) power system load frequency control (lfc) block diagram al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 figure (6) matlab simulink simulation model for the 4th order sg. without controller figure (7) frequency deviation (∆ω) for the simulation model without controller al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 523 figure (8) block diagram of the proposed governor system with pid controllers figure (9) frequency deviation (∆ω) step response for 0.6 p.u load change with pid controller al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 553 figure(10) optima pid control of s.g figure (11) the flowchart of the pso-pid control system start generate initial populations run the governor control of sg. model for each set set of parameters calculate the parameters {kp,ki,kd} of pid controller calculate the fitness function calculate the pbest of each particle and gbest of population update the velocity, position, gbest and pbest of particles maximum iteration number reached? stop no yes al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 551 figure (12) system performance of pso-pid tuning method . finite element analysis of fins with convection and radiation heat transfer al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 242 finite element analysis of fins with convection and radiation heat transfer dr. mohammed hamzaabdulsada phd. in mechanical engineering/department of mechanical engineering college of engineering, al-qadissyah university email:mohammedalhashmi@gmail.com cell phone: 00964-7809181781 received 10 novmber 2014 accepted 25 march 2015 abstract one dimensional analysis of heat transfer from fin is simple when only heat transfer by convection from fin surface. however, in some cases heat transfers by combined phenomena (convection and radiation), this makes the governing differential equation of heat transfer non-linear and the analytical solution becomes hard to solve. this paper uses an approximate method to solve the problem with high-quality results based on finite element technique. the method can be used for different types of fins and for different shapes. the results show suitable agreement between semi-exact solution and numerical solution. key-words: heat exchanger, fins, radiation, finite element. تحليل انتقال الحرارة من الزعانف بالحمل واإلشعاع باستخدام طريقة العناصر المحددة د حمزة عبد السادة الدكتور محم دكتوراه في الهندسة الميكانيكية الخالصة التحليل ببعد واحد النتقال الحرارة للزعنفة بسيط عندما تنتقل الحرارة من الزعنفة بواسطة الحمل فقط ولكن عندما تنتقل الحرارة من الزعنفة بواسطة التأثير المشترك للحمل واإلشعاع، المعادلة التفاضلية النتقال الحرارة سوف تصبح غير خطية ذه الورقة استعملت طريقة تقريبية لحل هذه المشكلة مع ظهور نتائج جيدة. والتي وسوف يكون الحل التحليلي لها صعب.ه هي تعتمد أساسا على تقنية العناصر المحددة. أن الطريقة المستخدمة يمكن أن تطبق على أنواع مختلفة وأشكال مختلفة من النتائج تشير الى توقف مناسيب بين الحل التحليلي والحل العددي الزعانف. notation a area 2 m t temperature kc o , ac cross section area 2 m av t average temperature kc o , al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 243 as surface area 2m b t base temperature kc o , h convection heat transfer coefficient cmw o2 / l t end temperature kc o , r h radiation heat transfer coefficient cmw o2 /  t environment temperature kc o , k thermal conductivity cmw o/ x space coordinates in cartesian system m l length m p perimeter m  emissivity q heat transfer rate sj /  shape factor conv q convection heat transfer rate sj /  temperature difference kc o , rad q radiation heat transfer rate sj /  stefan boltzmann constant 42 / kmw q heat transfer j subscript t thickness m x denotes some local position with respect to x coordinates m 1.introduction: it has been recognized that use of fins can facilitate an augmentation of the heat exchange between two fluids which are separated by solid interface and they are used in many engineering applications to improve heat transfer from a surface to its surroundings. in this project a simple one-dimensional model will developed for the heat flow in a fin of arbitrary shape. the resulting governing differential equation will be solved approximately in some simple cases.gaurav[1]has been shown method based on finite volume analysis with approximate results. this work tries to improve the results previously through the implementation of finite element method. this paper treats situations for which heat is transferred by diffusion under one-dimensional steadystate conditions. the term “one-dimensional” refers to the fact that only one coordinates is needed to describe the spatial variation of the dependent variables. hence, in a one-dimensional system, temperature gradient exits along only a single coordinate direction and heat transfer occurs exclusively in that direction. the system is characterized by steadystate conditions if the temperature at each point is independent of time. despite their inherent simplicity, one dimensional steady-state models may be used to accurately represent numerous engineering systems. it can be assumed that the heat transfer from fins is one-dimensional steady-state heat transfer, and the heat dissipates from fins by convection and radiation to the environment, the governing differential equation can be solved exactly if heat transfer by convection to the surrounding but when heat transfer by both convection and radiation, exact solution of the non-linear differential equation will be so difficult and in some cases impossible according to the boundary condition of the case under analysis. finite element solution[2-3] is the method used here to find the temperature distribution a long fin length and the amount of heat transfer from the fin of the compound effect of convection and radiation heat transfer. 2.theoretical analysis : to determine the heat transfer rate associated with a fin, firstly mustobtained the temperature distribution along the fin. starting performing an energy balance on an appropriate differential element[4-5]. consider the extent surface on fig. (1). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 244 the analysis is simplified if certain assumptions are made. choosing one-dimension conditions in the longitudinal (x) direction, even though conduction within the fin is actually two dimensional. the rate at which energy transfers to the environment by compound effect convection and radiation from any point on the fin surface must be balanced by the rate at which energy reaches that point due to the conduction in transverse (y, z) direction. practically the fin is thin and temperature changes in the longitudinal direction are much larger than the transverse direction. hence, itmay be assumed onedimensional conduction in the (x) direction. it will be considered steady-state conditions and also it assumed that the thermal conductivity is constant, that the heat generation effects are absent, the convection heat transfer coefficient (h) is uniform over the surface, the surface emitted as a blackbody, thus the emissivity is constant andequal unity ( 1 ). applying the conversation of energy requirement to the differential element of fig. (1), obtain[4-5]: radconvdxxx dqdqqq   (1) from fourier’s law dx dt kaq cx  (2) since the conduction heat rate at ( dxx  ) may be expressed as dx dx dq qq x xdxx   (3) it follows that dx dx dt dx d ka dx dt kaq ccdxx         (4) the convection heat transfer rate may be expressed as     ttdahdq sconv (5) the radiation heat transfer rate may be expressed as  44   ttdadq srad  (6) substituting the forgoing rate equations into the energy balance equation (1), obtain     0 44 2 2   tt dx da tt dx da h dx td ka ss c  (7) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 245 2.1. semiexact solution equation (7) is difficult to be solved exactly unless some assumptions are made to overcome this difficulty[6]. the heat transfer by radiation from the fin surface in the equation (6) can be written in the form       ttttttdadq srad 22  (8) and it can be assumed that the temperature on two first term approximately equal to the average temperature of the fin surface  avtt  , thus equation (8) can be write       ttttttdadq avavsrad 22  (9) substituting equation (9) into equation (7)       0 22 2 2   tt dx da tttth dx td ka s avavc  (10) it is necessary to be more specific about the geometry. two cases of fins rectangular will analysis and pin of uniform cross sectional area. it can be observed: 1. each fin is attached to a base surface of temperature btt )0( and extent into a fluid of temperature  t . 2. for the prescribed fins, ca is a constant and, 3. pxas  where sa is the surface area measured from the base to x and p is the fin perimeter. accordingly with pdxdas  . 4. radiation heat transfer coefficient      tttth avavr 22  equation (10) can be modified know to the form     0 2 2          tt ka phh dx td c r (11) to simplify the form of this equation, transforming the dependent variable by defining an excess temperature ( ) as       txtx (12) where, since  t is a constant dxdtdxd  substituting equation (12) into equation (11), obtain 0 222   mdxd (13) where al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 246           c r ka phh m 2 (14) equation(13) is a linear, homogeneous second order differential equation with constant coefficients. its general solution is of the form   mxmx ececx  21  (15) to evaluate constants 21 , cc of equation (15) it is necessary to specify appropriate boundary conditions. such conditions may be specified in term of temperature at btt 0 x and    ttb0b  there are four cases: case a convection and radiation heat transfer from the tip at lx  can be written in the form    lxlx r dx d k dx dt ktthh     (16) assume  rt hhh  (17) thus re-write equation (16)   lx t dx dt ktth    (18) by solving equation (15) the temperature distribution is mlmkhml xlmmkhxlm t t b sinh)(cosh )(sinh)()(cosh      (19) applying fourier’s law at the fin base in order to find heat transfer from the fin 0  x cbf dx dt kaqq (20) thus, mlmkhml mlmkhml mq t t f sinh)(cosh cosh)(sinh    (21) where     ttpkahm bct (22) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 247 case b convection and radiation heat transfer from the tip at lx  is negligible, which means thatthe tip is adiabatic and the second boundary condition is: 0  lxlx dx d k dx dt  (23) by using the boundary conditions and solving equation (15), the temperature distribution is ml xlm b cosh )(cosh     (24) and fin heat transfer rate is mlmq f tanh (25) case c prescribed temperature at the tip of the fin lx  and the second boundary condition is     ttl l  l (26) using equation (15) with this boundary conditions, the temperature distribution is   ml xlmmx bl b sinh )(sinhsinh      (27) and the fin heat transfer is           ml mx mq bl f sinh cosh  (28) case d the very long fin (infinite fin) is an interesting extension of these results. in particular, as 0,  l x  and it is easy verify that mx b e     (29) and the fin heat transfer is mq f  (30) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 248 after summarizing the general cases that occur in fins, a computer program was developed to calculate the temperature distribution along the fin and the rate of heat transfer at the end of the fin. the following flow chart fig. (2) explain were followed: 2.2. finite element solution in the above solution using semi-exact solution, now consider the method of finite element solution for the same problem using 2-nodes element[2-3, 6-7]. the general equation of the heat transfer from the fins can be write in the following form    dxxtxhdx dx dtka tqtq ll c         0 2 0 1122 2  (31) the general solution of one-dimensional rod by using 2-nodes elementas shown in fig. (3) can be satisfy through the following analysis. assume that the temperature distribution through the rod can be write      2 1i ii ntxt (32)        n i ji j ji j i xx xx n 1 1 (33) assume that the shape factor is l x  (34) substitution in equation (33) for three node, find the node element as a function of         1 11 nxn (35)       22 nxn (36) the temperature distribution along fin can be write in matrix form as flows            2 1 21 t t nntnntxt tt (37) from equation (34), can write lddx  now substitute the above assumption into equation (31) and can be write in the form          dthld d dt l ka q q tt c                1 0 21 0 1 21 2 1 2 (38) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 249                   d dn d dn tt d dt 2 1 21 (39)          1 2 11   d dn d dn (40) equation (38) can be write as flows    dnthldtrrt l ka qt tttct   1 0 1 0 2 1 (41) where                d dn d dn r 2 1 (42) according to theorems i.   bbt      (43) ii.   bb t         2 1 (44) whereb issquare matrix when 0   t  equation (41) will become    dnhldtb l ka q c   1 0 1 0 0 rearrange the equation above    dnhlqdtb l ka c   1 0 1 0 (45) having three terms in the above equation, will treat with them individually dtb l ka thl c  1 0 .. (46) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 250 where matrix rrb t  (47) and thus the symmetric matrix equal to                            2 212 21 2 1   d dn d dn d dn d dn d dn d dn b (48) substituting the above matrix in equation (46) and after integration the equation become                2 1 11 11 .. t t l ka thl c (49) the other term of the equation (45) can be write in the following equation         2 1 q q q (50) and the other term can be write    dnhlthr  1 0 .. (51) the heat transfer from the fin surface divided in two main methods convection and radiation, thus re write the equation (51) in form       dnhrhclthr   1 0 .. (52)         dnttptthplthr    1 0 44 ..            dnttttttpldntthplthr avav    1 0 22 1 0 ..       dnttplhhplthr r    1 0 .. t plh (53) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 251          dtnndntthr t 1 0 1 0 .. after integration the above equation the right hand term can be write in the following form                           2 1 21 12 6 1 1 1 2 .. t tt thr  (54) substitution the equations (49),(50)and(54) into equation(45), the final equation as follows                                               2 1 2 1 2 1 21 12 6 1 1 1 211 11 t tt q q t t l ka c  (55)                                         1 1 221 12 611 11 2 1 2 1 t q q t t l ka c  (56) equation (56) the final equation represent the finite element solution for two node elements , after summarizingthe solution, below the general steps to find the temperature distribution and heat transfer from the fin explained in flow chart fig.(4). the steps above are general and can be slightly differingif use 3-nods element or more than two elements and the detail of the solution can be differ also. so, using the 3-nodes element,depend upon the same analysis above the final equation of three nodes element is                                                                       1 4 1 6 842 4324 248 60 781 8168 187 3 3 2 1 3 2 1 t q q q t t t l ka c  (57) 3.case study heat flow through a copper rectangular fin has a thermal conductivity 400w/mk, shown in fig. (5), having a thickness 0.01m, width 0.01m and length 0.2m is attached to a boiler surface having a temperature of 100 c o . the fin is exposed to ambient air and its convicting and radiating heat to the environment at temperature of 25 c o , and convection heat transfer coefficient along the length and the end is 20w/ 2 m k, the fin emissivity 1 and the stefan-boltizmann constant 5.7e-08 w/ 42 km . determine the temperature distribution and the heat transfer from the fin.moreover, change the fin metal by 1. aluminum(k=180w/mk) 2. stainless steel (k=14w/mk) this change wouldaffectthetemperature distribution along fin length. to solve the case study in semiexact using the general step in section 2.1 and according to the boundary conditions the problem is case a and in finite element solution has been used the steps in section 2.2 and solve in 2-nodes two elements and 3-nods one element. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 252 4.results and discussions after following the procedure above, first table (1) shows the temperatures along fin length in three points.these results represent all cases of our analysis and it can be seenthat exact method in first column with convection heat transfer only. the results shows the temperature distribution along the fin, it observed that the effect of radiation can be clear if temperature of the base is high and with a greater value of emissivity and this factis clear from equation (17). the case study indicted from table (1) there is a small difference between the temperature values with convection heat transfer and with those with compound effect of convection and radiation heat transfer and this can be shown in fig. (6). it is clear from table (1) that the methods used to calculate combined effect of convection and radiation heat transfer give good results especially between semi-exact method and with finite element method used 3-nods with those two methods slightly differ from the other finite element method used 2-nods with two elements and this clearly shown in table (1) and fig. (6). fig. (7) shows the effect of changing fin materials and it is clear from fig. the heat transferred from stainless steel fin is larger than those of copper and aluminum and this difference belong to thermal conductivity differences between materials of fins. the effect of changing emissivity can be shown in fig. (8) and it is clear the temperature decrease with increase of emissivity value because of increase of emissive heat by radiation from the fin surface especially when the distance from the base increase. 5. conclusion radiation heat transfer is an important factor in heat transfer calculation and its value effect is differing according the amount of this value and the interest of application. this paper trying to indicate the radiation effect on fins calculation, the value of radiation depend on the emissive of the body surface and temperatures of surface body and environment when any of those variables increase the radiation heat transfer coefficient increase that mean radiation heat transfer increase. the method used in analysis is good and give good results and there is good approximation between semi-exact solution and numerical solution and from the result, notice the finite element technique with 3-nodes element give result nearest from exact results. the value of thermal conductivity increase the heat transfer from the fins when decrease. it can be neglected the radiation value if the base temperature of the fin is low and the emissivity of the fin surface is nears zero. the important things in fins surface must be emissive because of high emissivity give a great amount of heat radiation transfer from the fin. 6. references: [1] gurav, r.b., et al., finite volume analysis of convective heat transfer augmentation from horizontal rectangular fin by elliptical perforation. international journal of global technology initiatives, march 2013 2(1). [2] comini, g., finite element analysis in heat transfer: basic formulation & linear problems. 1994: taylor & francis. [3] bathe, k.-j. and m.r. khoshgoftaar, finite element formulation and solution of nonlinear heat transfer. nuclear engineering and design, 1979. 51(3): p. 389-401. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 253 [4] holman, j.p., heat transfer. 2010: mcgraw hill higher education. [5] incropera, f.p., et al., fundamentals of heat and mass transfer. 2011: wiley. [6] mackerle, j., heat transfer analyses by finite element and boundary element methods. a bibliography (1997–1998). finite elements in analysis and design, 2000. 34(3–4): p. 309-320. [7] mackerle, j., finite element and boundary element modelling of surface engineering systems: a bibliography (1996–1998). finite elements in analysis and design, 2000. 34(1): p. 113-124. table (1): shows the results of exact, semi-exact and numerical solutions. convection convection and radiation heat transfer temperature exact solution without radiation semi-exact solution fem,2-nodes, 2 elements fem, 3-nodes, 1 element   mxct o 0, 11  100 100 100 100   mxct o 1.0, 22  82.6973 77.89197 77.53397 77.87332   mxct o 2.0, 33  77.12766 70.96069 70.5105 70.99628 total heat transfer from the fin )(wq 9.646632 12.55253 11.7958 12.55664 figure (1): energy balance of one-dimensional conduction, convection and radiation through a fin. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 254 figure (2): flow chart of fins heat calculation     ttpkahm bct   tt bb  specify which case of cases (a,b,c,d) is correspondence with your boundary conditions of you case study sum=0 num=0 for x=0 to l step x1 calculate temperature according to the case you are study it t(x1). num=num+1 rad radrad qnew qoldqnew diff   sum=sum+ t(x1) next x1 fins heat transfer calculation input  ttlpakh bc ,,,,,,,,  2    tt t b av  44   ttplqold avrad       tttth avavr 22         c t ka ph m 2 rt hhh  if 00001.0diff then go to step 3 calculate fin heat for the case you are study end yes no al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 255 figure (3): local system and intrinsic system for one-dimensional rod al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 256 figure (4): flow chart of fins heat calculation (fem) semi exact solution input  ttlpakh bc ,,,,,,,,  2    tt t b av  44   ttplqold avrad      avav ttttplhpl   22  using two elements in the finite element solution 3 321 ttt t av   rad radrad qnew qoldqnew diff    44   ttplqnew avrad  calculate fin heat flow for the case you are study using fourier law if 00001.0diff then go to step 3 end according to cases (a,b,c,d) you will specify your boundary conditions of the case and these boundary conditions will help to determine the value of q . calculate temperature distribution t according to the case using equation (56). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 257 figure (5): rectangular fin of the case study 70 80 90 100 0 0.05 0.1 0.15 0.2 t e m p e r a tu r e d is tr b u ti o n ( c ) fin distance from the base (m) figure (6):temperature distrbution alonge the fin length eaxt solution without radiation semi-exact solution with radiation fem, 2 nodes, 2 elements with radiation fem, 3 nodes, one elements with radiation l x w t al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 258 20 40 60 80 100 0 0.05 0.1 0.15 0.2 t e m p e r a tu r e d is tr b u ti o n ( c ) distance from the fin base figure (7):temperature distrbution of different fin materials copper aluminum stainless steel 70 80 90 100 0 0.05 0.1 0.15 0.2 t e m p e ra tu re d e g re e ( c ) distance from the fin base figure (8):temperature distrbution of different value of emissivity for aluminum emissivity=0.1 emissivity=0.5 emissivity=1.0 template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 446 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fabrication and wear properties of za-27 alloy matrix hybrid composite reinforced with nanoparticles dr. fadhil abbas hashim, university of technology, materials engineering, baghdad, iraq . e mail: hashembsb@yahoo.com dr. niveen jamal abdulkader, university of technology, materials engineering, baghdad, iraq e mail: niveen.alwandawy@yahoo.com kateralnada faris hisham university of technology, materials engineering, baghdad, iraq e mail: nadaalhyali@gmail.com abstract: in this research stir casting technique is used to produce (za-27)alloy hybrid composites reinforced by nano particles (bn and si3n4) with various weight percentage.the wear test were used pin on disk for both (za-27) alloy and all composites.the results indicate that the value of hardness increased with increasing the additives of nano (bn and si3n4) percentage for za-27 hybrid metal matrix composites. it was found that the nano particles play an important role in improving the wear properties of alloys. since nano particles impede dislocations movement, causing enhancement in the mechanical properties. keywords: za-27 alloy, stir casting, hybrid composite, nanoparticles, hardness &wear rate. 1. introduction zinc aluminum alloy (za alloys) are widely used in for both scientific researches and industry, as a tribomaterials , due to its good castibility and other properties, which become an alternative alloy for bearing al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 447 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. bronze [s. s. owoeye,, et al., 2018]. they are known to be cheap material processed energetically, efficiently and without endangering the environment ] w. k. meyers , et al. 2003[ . za-27 have higher aluminium and copper contents which give high strength, excellent wear and creep resistance, and lower density [ s. c. krishna, et al. 2006], however, when wear resistance properties are needed, za-27 has demonstrated extraordinary performance ] y. h. zhu , 1999[. nowadays, the most researchers studied the properties of the za-27 alloy reinforced with ceramic dispersions such as silicon carbide and graphite for improving mechanical and tribological properties[w. k. krajewski, 2006]. the purpose of applied metal matrix composite based on za-27 matrix because its light weight and good mechanical and wear properties [m. kaplan,, et al..2008 [ . the hybrid metal matrix composites contains two or more types of reinforcements. reinforcements in terms of mixtures of particles, whiskers and fibers with different weight percentage and varying sizes are utilized in metal matrix for multi functional properties [h., j. looney, et al. 2002]. seah et al. 1995, investigated that the hardness of artificial aged specimens of za-27/gr increased as compared with as cast alloy. babic et al. 2009, tested ultimate tensile stress for za-27 alloy and heat treated it, the results showed reduce uts and hardness with increase in elongation for as cast alloy while for heat treated alloy showed reduction in hardness. ranganath et al. 2002 evaluated the effect of weight percentages of tio2 additives as a reinforced particles on the mechanical properties of za-27. the results indicated that the reinforce particles reduced alloy ductility, and improved uts, yield strength and hardness. prasad, et al. ,1998, studied the effect of micro structure composition on the tensile property of za-27 alloy. experiments were performed at different strain rates and temperature. the results showed that the tensile strength of the alloy was improved with increase in the strain rate. the aims of this study is to evalute the mechanical behavior and study the microstructure of za-27 alloy by using a recycled alloys produced by stir casting, and to study the effect of hybrid composite with different percentages of nanoparticles on mechanical properties. 2. methods and materials a. materials selection a. matrix materials matrix material used in this research was za-27 which has excellent properties with a wide range of applications .its chemical analyzes composition is shown in table (i). http://adsabs.harvard.edu/cgi-bin/author_form?author=sharma,+s&fullauthor=sharma,%20s.%20c.&charset=utf-8&db_key=phy http://adsabs.harvard.edu/cgi-bin/author_form?author=krishna,+m&fullauthor=krishna,%20m.&charset=utf-8&db_key=phy al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 448 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table i. chemical analyses of astm za-27 ] 12[ zn% pb% cd% fe % mg% cu % al% element rem 0.004 0.003 0.1 0.01-0.02 2-2.5 25-28 nominal chemical comp . standard rem 0.0006 0.0011 0.054 0.013 2.17 26.23 actual chemical composition of za-27 alloy b. nano boron nitride and nano silicon nitride as a reinforcing materials ceramic powders (nano bn and nano si3n4) were used as reinforcement materials for za-27alloy. the morphology of raw powders were studied with scanning electron microscopy (sem) as shown in fig. 1. nano bn nano si3n4 fig. 1 sem of nano (bn and si3n4 ) powders. b. production of matrix material and its composite producing of matrix material (za-27alloy) it used the weight of melting alloys was approximately equal to 264 gm , which included 185 gm electrolytic zinc (99.99%) ,78 gm pure aluminum , 20 gm master alloy 50 cu50al and 10 gm aa2024. the melting for all alloys was done in a graphite crucible by using gas furnace to about 700 °c (above its melting point) to ensure full melting [13]. the molten material was mixed using a mechanical stirrer to get a homogenous mixture. flux cleaning (kclnaclnaf) with weight percentage 0.25% were used which usually rich in chlorides to facilitate wetting of the oxide inclusions for easier separation from the melt. for reducing the impurities and gases by using hexachlorethane as degassing [14]. the reinforcement nanoparticles (bn, si3n4) with different weight percentages were added to the melted matrix as packaged in aluminum foil and continuously stirred using a mechanical stirrer at speed 1000-1200 rpm. to obtain a uniform mixing for all melted material. the slag was removed and then pouring the molten al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 449 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. material into a cylindrical graphite mold (permanent mold casting) for casting and the temperature was gradually lowered. fig.2 and fig.3 show the mold preparation and sketch of mold with dimensions, respectively. fig.3 sketch of mold with dimensions. (all dimensions are in mm) c. hardness: hardness test was carried on the base metal alloy and its composites using standard vickers hardness test machine. the applied load was 0.2kg. square based diamond pyramid indenter was used during the test. d. wear test: resistance to surface wear of cast za-27 alloy and reinforced with nano boron nitride (bn) and nano silicon nitride (si3n4) were evaluated using pin on disc type wear tester as per astm g99-95 standards. the sample dimensions were φ10mm with 30 mm for length. the tests were made using applied load of 5, 10,15,20 n , the disk rotential speed was 950 rpm and a sliding velocity 6 cm/min and for 15 min. the disk was made of stainless steel with 63 hrc hardness. e. microstructure: scanning electron microscope was used to study the microstructure of za-27 alloy and its composites. were investigated by using (inspect s 50 device) and the magnification employed on the samples ranges from 10020000x. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 450 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3. results and discussion a. micro hardness measurement: the value of vickers micro hardness are given in figure (4). the results indicate that the hardness of za-27 alloy and its composite increased when increasing the weight percentage of nano particles. the presence of hard reinforcement particles (bn and si3n4) increase load bearing capacity of the composite material and also limit the matrix deformation by impeding the movement of dislocation. the maximum value of hardness were observed at (3%bn and 3%si3n4) weight fraction. fig.4 micro hardness values of za-27 alloy and its composites. b. wear rate measurement: the wear rates of composites were increased with increaseing ia addition of nano particles additives as shown in fig (5). moreover, increasing the load caused an increase in wear, showing the transition of mild wear to severe wear. however the transition was more pronounced in alloy compared to composites. perhaps the increase in reinforcement has resulted in the increased hardness and causes the surface barrier for the penetration of hard particles into the surface. the minimum wear loss was observed for za-27/3%bn/3%si3n4 reinforcement compared to other materials studied at all different loads considered in the study. the wear rate decreasing for hybrid composites with increasing nanoparticles. this due to the presence of both of the reinforcing materials, which assume to form a stable film on surface composites [15]. the nano al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 451 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. ceramic particles improve the hardness and wear properties of the composite, and help in the formation of a stable tribolayer. the hybrid composites improved the hardness and lower wear rate than the unreinforced matrix. the wear properties of za-27 hybrid composites with nano particles additives as a solids lubricant. the hybrid composites had 3 wt% bn with 3wt% si3n4 it was greater mechanical properties than the single reinforced za-27 2wt% bn composite and za-27 2wt% si3n4. fig.5 wear rate values for za-27 alloy and its composites of different loads c. microstructure analysis the microstructure was used by sem. it noticed uniform dispersion of reinforcement in the matrix. the microstructure is dendritic and contributed to fragmented that due to uniform stirring then improving the incorporated and entrapped th nano-sized particles within the interdendritic interface. so the microstructure observed no agglomeration of reinforcement in the matrix that was noticed in fig (6). al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 452 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. a b c d e fig.6 sem images of za-27 alloymatrix with nano particles at different weight percent. a) za-27 alloy b) za-27 alloy/2%bn c) za-27 alloy/2% s3n4 d) za-27 alloy/2%bn+2% si3n4 e) za-27 alloy/3%bn+3% si3n4 al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 453 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 4. conclusion  the micro hardness values for za-27 alloy and composite material was increased with increasing the reinforcement percentage .  the za-27 composite reinforced with (3% bn+3%si3n4) hybrid nanocomposites exhibited lower wear rate due to presence of two ceramic materials.  the microstructure of za-27 alloy is dendritic structure, and the hybrid composites reinforced with nano particles observed to be uniform distribution and noting to presence the agglomeration particles. thus, increased nanoparticles with weight percentage increases the mechanical properties of the composite.  the hybrid composites were cast successfully with liquid metallurgy technique. references 1s. s. owoeye, d. o. folorunso, b. oji & s. g. borisade,, , “zincaluminum (za-27)-based metal matrix composites: a review article of synthesis, reinforcement, microstructural, mechanical, and corrosion characteristics”, the international journal of advanced manufacturing technology”, springer nature, 2018. 2w. k. meyers, "zinc-aluminum alloys as tribomaterials" ,journal metals, vol. 22, no. 4, dec 2003, p. 259. 3 s. c. krishna, m. bhattacharyya, "dry sliding wear behavior of reinforced za-27 alloy based metal matrix composites" international journal of modern physics b, vol. 20, issue 25-27, 2006, pp. 47034708. 4y. h. zhu ,"microstructure dependence of damping behavior of eutectoid zn –al based alloy (za-27)", j. mater. sci. tech. ,vol. 15, no.2, 1999. 5 w. k. krajewski , "shaping surface wear properties of the zn-al based mmcs", metallurgia italiana,2006 ,pp 27-30. 6m. kaplan, m. ileriturk, z. balalan, "relationship between microstructure, hardness, xrd and wear performance of cast za alloy", materials and manufacturing processes, 2008,pp400-406. 7h., j. looney, l. and hashmi, m.s.j. particle distribution in cast metal matrix composites-part i. journal of materials processing technology, 123(2), 2002, 251-257. 8s., k.h.w. sharma, s.c.; and girish, b.m. effect of artificial ageing on the hardness of cast za27/graphite particulate composites. materials and design, 16(6), 1995,337-341. 9b., m.; mitrovic, s.; and ninkovic, r. tribological potential of zinc-aluminum alloys improvement. tribology in industry, 31(1-2), 2009, 15-28. http://adsabs.harvard.edu/cgi-bin/author_form?author=sharma,+s&fullauthor=sharma,%20s.%20c.&charset=utf-8&db_key=phy http://adsabs.harvard.edu/cgi-bin/author_form?author=krishna,+m&fullauthor=krishna,%20m.&charset=utf-8&db_key=phy http://adsabs.harvard.edu/cgi-bin/author_form?author=bhattacharyya,+d&fullauthor=bhattacharyya,%20d.&charset=utf-8&db_key=phy al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 454 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 10 r., g.; sharma, s.c.; krishna, m.; and muruli, m.s. , a study of mechanical properties and fractography of za-27/titanium-dioxide metal matrix composites. journal of materials engineering and performance, jmepeg, 11(4), 2002, 408-413. 11p., b.k., tensile properties of some zinc-based alloys comprising 27.5% al: effects of alloy microstructure, composition and test conditions. materials science and engineering: a, 245(2), 1998, 257-266. 12annual book of astm standers, standard specification for zinc alloys in ingot form for foundry casting, vol. 2.04, b669-84e1, 1988. 13asm handbook, "casting ", vol. 15, 1988. 14k., t. s., m. prasanna kumar, basavarajappa, s., vishwanatha, b. m., “mechanical properties of as-cast za-27/gr/sicp hybrid composite for the application of journal bearing”, journal of engineering science and technology, vol. 8, no. 5 2013, 557 – 56. 15r. harichandran, and n. selvakumar, "effect of h-bn solid nano lubricant on the dry sliding wear behaviour of al-b4c nano composites", international scientific journal published monthly by the world academy of materials and manufacturing engineering, vol 77, issue 1, pp 5-11, (2016). al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 statcom application in 400kv iraqi super grid for voltage magnitude improvement shatha s. abdulla al-kubragyi university of technology electrical department shatha_suhbet@yahoo.com received 20 feb 2014 accepted 16 july 2014 abstract this paper presents a study of static synchronous compensator (statcom). one of the flexible ac transmission system (facts) devices, it can significantly improve power systems stability. consisting of voltage sourced converters connected to an energy storage device on one side and to the power system on the other, it specifically can provide reactive support to buses. this work presents a simple algorithm for identifying weak buses to determine the best location for statcom. singularity of the power flow jacobian matrix as an indicator of steady-state stability has used, the sign of the determinant of the load flow jacobian was used to determine the system stability, by computing eigenvalues, eigenvectors , minimum singular value of loadflow jacobian matrix and sensitivity analysis between power flow and bus voltage changes. load flow analysis of the iraqi grid 400 kv network has been carried out using newton rephson method with and without statcom. the result of load flow analysis show improvement in bus voltage with the use of statcom in the system. keywords: fact, statcom, load flow, voltage stability. الفولتية قيمة( لتحسين 044)kv عراقية ال الفائق في شبكةالضغط statcomتطبيق شذى صحبت عبدهللا الكبراغي الجامعة التكنولوجية قسم الهندسة الكهربائية الخالصة: يث،ح المرنة المتردد التيار نقل نظام أجهزة من واحد .(statcom) المتزامن المعوض ثابت دراسة تم البحث هذا في على الطاقة تخزين جهاز إلى متصلة الجهد مصادر محوالت من يتكون. الطاقة أنظمة استقرار كبير حد إلى يحسن أن يمكن .التفاعلية بالقدرة bus لل دعم توفر أن يمكن التحديد وجه على فإنه أخرى، جهة من الطاقة ونظام واحد جانب استخدمت ،statcomل موقع أفضل لتحديد الضعيفة buses لتحديد يطةبس خوارزمية على االعتماد تم العمل هذا في singularity لمصفوفة المحدد أشارة اعتماد تم ،حيث النظام استقرارية على كمؤشر الطاقة لتدفق جاكوبين لمصفوفة الذاتية هاتالمتج ،(eigenvalue) الذاتية القيم حساب خالل من النظام، استقرار لتحديد الحمل لتدفق جاكوبين (eigenvectors) ، وminimum singular value تدفق بين االستجابة وتحليل لسريان الحمل جاكوبين لمصفوفة .الجهد مجمع وتغيرات الطاقة mailto:shatha_suhbet@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 التحليل ونتائج .statcom وبدون مع رافسن نيوتن طريقة باستخدام كف ٠٤٤ العراقية للشبكة الحمل سريان تحليل تم .النظام في statcom بأستخدام bus voltage)) الجهد مجمع في تحسنا تأظهر ., سريان الحمل , استقرارية الفولتية ,fact , statcomالكلمات الرئيسة : list of symbols: facts: flexible ac transmissions system. isg: iraqi super grid. statcom: static synchronous compensator. , active and reactive power mismatch , voltage magnitude and voltage angle mismatch 𝜕 𝜕 : partial derivatives of the real and reactive power. 𝜕 𝜕 : partial derivatives of the voltage magnitude and voltage angle . y admittance :mismatch active power at kih bus in i iteration  k i q : mismatch reactive power at kih bus in i iteration specified accuracy for active and reactive power mismatch j jacobin matrix jr reduced jacobin matrix right and left eigenvector of matrix jr diagonal eigenvalue of matrix jr the ith eigenvalue. the ith of column right eigenvector. the ith of row left eigenvector ith modal reactive power variation ki normalization factor. pki participation factor of the kth bus in ith mode . pk ,qk active and reactive power injection at bus k. vk voltage at bus k vj voltage at bus j. ykj admittance between bus k and bus j.  k i p al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 090 pstat statcom active power. qstat statcom reactive power. statcom voltage. statcom admittance. gstat , bstat conductance and suspectance of statcom. 1. introduction voltage control and stability problems are not new in the electric power system industry but are now receiving special attentions. voltage stability is the ability of a power system to maintain voltage irrespective of the increase in load admittance and load power resulting in control of power and voltage [1]. a system is said to enter a state of voltage instability when a disturbance causes a progressive and uncontrollable decline in voltage, which can occur because of the inability of the network to meet the increased demand for reactive power [2], which lead in the worst case, in the collapse of the power system. appropriate voltage and reactive power control are one of the most important factors for stable power system. where, the distribution system losses and various power quality problems are increasing due to reactive power [3]. there are several studies [2, 4, 5] focused on measures to predict system conditions with respect to voltage stability and optimal control actions to avoid collapse in the online paradigm. as most of these problems are highly nonlinear and computationally intensive, there is a need of research to help in reducing computation and using direct measurements for estimation of stability margin. many analysis methods [6, 7] of voltage stability determination have been developed based on the load flow solution, optimal power flow, bifurcation technique, singularity of jacobin etc. different voltage stability indicators have also been established covering both static and dynamic aspects of the problem. efforts also have been made to assess the voltage stability of large power systems in terms of network equivalents to obtain the global picture of voltage stability [2]. now, more than ever, advanced technologies are paramount for the reliable and secure operation of power systems. power electronic based equipment, such as facts controllers, are the most effective way for utilities to improve voltage stability of the system with their capability to respond rapidly the system events, increase power transfer limits, and improve the quality of power delivered, constitute one of the most-promising technical advancements to address the new operating challenges being presented today [8].the static synchronous compensator (statcom) is one of the most important facts devices, a regulating device used on alternating current electricity transmission networks and it is based on the principle that a voltage-source inverter generates a controllable ac voltage source behind a transformer leakage reactance so that the voltage difference across the reactance produces active and reactive power exchange between the statcom and the transmission network [9, 10]. this paper focuses on one such facts controller for voltage support as a reactive power (var) source, namely the static compensator (statcom). a systematic analytical methodology based on modal analysis of the modified load flow jacobian matrix has been used as a static voltage stability index to determine the best location for statcom. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 2. power flow solution a power flow or load flow program computes the voltage magnitude and angle at each bus in a power system. once they are calculated, real and reactive power flows for all equipment interconnecting the buses, as well as losses are also computed. there are two ways to represent the bus voltage equations to solve the load flow problem, the rectangular and polar coordinates of bus voltages. it is prefer to use polar coordinates to formulate the power flow equation. as the power flow method is implemented for voltage stability analysis, the jacobian matrix of solved load flow equations, by newton-raphson method, can be used. the linearized steady-state system power voltage equation is expressed as [11]: [ ] [ | | | | ] [ | | ] (1) the jacobin matrix can be written as: [ ] [ ] [ | | ] (2) the jacobian matrix gives the linearized relationship between small changes in voltage angle and the voltage magnitude with the small changes in real and reactive power mismatch and . elements of the jacobian matrix are partial derivatives of the real and reactive power, evaluated at and .and for more details in [9, 11]. the procedure for power flow solution by the newton-raphson method is as follows: 1. read system and load data (including identified the slack bus, generator bus (pv) bus, and load bus pq ). 2. form the nodal admittance matrix [y]. 3. initialize δ, v 4. calculate p and q. 5. calculate jacobian matrix (2. through 1). 6. solve for the voltage angle and magnitude. 7. update the voltage magnitude and angles. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 8. check the stopping conditions. if met then terminate, else go to step 3.         k i k i q p to express the relation between q and v for small change in real power p=0 is assumed so that equation (2) leads to be: vjjp  12110  vjj   12 1 11 (3) and vjjq  2221  (4) substituting equation (3) in equation (4): vjjj j q   ) 22 ( 12 1 1121 (5) the expression in the brackets in (5) represents the reduced jacobian matrix rj of the system. it relates the bus voltage magnitude and reactive power injection. the eigenvalues and eigenvectors of the reduced order jacobin matrix rj are used for the voltage stability characteristics analysis. voltage instability can be detected by identifying modes of the eigenvalues matrix rj . the magnitude of the eigenvalues provides a relative measure of proximity to instability. the eigenvectors on the other hand present information related to the mechanism of loss of voltage stability. let assume  .. 12 1 1121 22    jjj jr j (6) al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 where: ξ= right eigenvector matrix of rj  = left eigenvector matrix of rj  = diagonal eigenvalue matrix of rj . equation (6) can be written as:  11   r j (7) using equation (1) and (2) the incremental changes in reactive power and voltage are related by: (8) or qv i i     (9) where i is the th i eigenvalue, is the th i of column right eigenvector and is the th i of row left eigenvector of matrix rj . i ,ξi, and i define the i th mode of the system. the th i modal reactive power variation is: imi kq  ξ i (10) where ik is a normalization factor the appropriate definition and determination as to which node or load bus participates in the selected modes become very important. this necessitates a tool, called the participation factor, for identifying the weakest nodes or load buses that are al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 making significant contribution to the selected mode and is suitable for statcom placement. if ξ and represent the right and left hand eigenvectors, respectively, for the eigenvalue λi of the matrix jr, then the participation factor measuring the participation of the kth bus in ith mode is defined as [11,12 ]: such that ∑ (11) with ξji the th j element of ξ i the corresponding th i modal voltage variation can therefore be written as: mi i mi qv   1 (12) pki = (13) 3. statcom – static synchronous compensator the stastcom is one of the important shunt connected ‘flexible ac transmission system’ consisting of a power electronics device connected with a capacitor or reactance. a step down transformer, called coupling transformer, is needed to reduce the voltage level of the bus where the statcom is installed as shown in the figure (1) [13]. it regulates the voltage at its terminals in power system, having as an ultimate goal the increase in transmittable power, and improvements of steady state transmission characteristics and of the overall stability of the system. under light load conditions, the controller is used to minimize or completely diminish line over voltage; on the other hand, it can be also used to maintain certain voltage levels under heavy loading conditions [14]. some papers discuss how to model statcom for load flow calculation. so, the bus at which the statcom is connected is represented as a pv bus , which may change to a pq bus in the events of limits being violated depending on its primary application.. in such a case, the generated or absorbed reactive power would correspond to the violated limit, the statcom is represented as a voltage source for the full range of operation, enabling a more robust voltage support mechanism. in a load flow calculation, a statcom is typically treated as a shunt reactive power controller assuming that it can adjust its injected reactive power to control the voltage at the statcom terminal bus [11, 15]. this means that the statcom absorbs proper amount of reactive power . the power system to keep vk constant for all power system loading within reasonable range, the ohmic loss of the statcom is accounted by considering the real part of ystatin power flow calculations. the net active/reactive power injection at bus k including the local load, before addition of the statcom, is known by pk+jqk. the power flow equations of the system with statcom connected to bus k, can written as [16]: al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 ∑ | | | || | (14) ∑ | | | || | (15) | | | || || | (16) | | | || || | (17) for more detail in [16].figure (2) depicts a statcom and the traditional simple model used in this paper for load flow calculation. in this model reactive power load at bus i, jqi, is combined with statcom reactive power output[11, 15], and figure (3) show the flow chart for power flow solution by newton-raphson with statcom. 4. case study the iraq super grid transmission line is large system having two voltage levels 400kv and 132kv; the network under consideration in this work is the 400kv super grid (isg). this network contains twenty four bus bar connecting with fourteen transmission line. the generation unit in the system are distributed at the twelve buses for the grid. the single line diagram isg for is shown in the figure (4). the bus data with power demand, generation are given in the data information illustrated in table (1). table (2) presents the load flow output results by using newton-raphson method. the system has one swing bus and eleven p-v bus so the total number eigenvalue of the reduced jacobin matrix  rj is expected to be (12), after employing eigenvalues at each load level, the buses are ranked in the order of the value of participation factor for these buses: the top ranked bus in the priority list has the greatest participation factor and refers as the weakest from others. the results of the eigenvalues and the participation factor are tabulated in the tables (3). note from the table all the eigenvalues are positive which means that the system voltage is stable. figure (5) shows the participating factor for the minimum eigenvalues of the system. it can be seen that the bus (19), (18) and (15) bus have the highest participation factor value to the critical mode. so, the most optimal bus to install statcom are buses 19, 18 and 15 respectively, 24-bus test system is used to assess the effectiveness of statcom model developed in this paper. the voltage profile of all buses without statcom is described in figure (6). it can be seen that all the bus voltage are within the acceptable level (±5%), the lowest voltage compared to the other buses can be noticed in bus number 24. the voltage profile of all buses with statcom installation at bus 19 and 15 also shown in figure (6). 5. conclusion statcom devices present an effective device in employing for voltage stability enhancement. the load flow studies are carried out with and without statcom and newton-raphson method is used in load flow. due to the high cost of facts controllers which improves voltage stability, facts devices installed localization studies is important to prevent additional costs. in this paper modal analysis algorithm for optimal location of statcom was used. the modal analysis provided important information about the proximity of the system to voltage instability. the results showed that the statcom can be used to improve an overall network voltage profile in practical power systems. additionally, in general more reactive power was available in al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 092 the network with statcom installed than without. the statcom and the detailed simulation are performed using matlab program. references [1]. d. bică, “static voltage stability analysis by participation factors computing, scientific bulletin of the petrumaior”, university of targu mures vol. 2 , 2006. [2]. s. h. palukuru and s. paul, “global voltage stability analysis of a power system using network equivalence technique in the presence of tcsc”, leonardo electronic journal of practices and technologies, issue 16, january-june 2010. [3] . s. sundarsingh, dr. r. raja prabu , “performance of thirty bus system with and without statcom” ,international conference on trends in electrical, electronics and power engineering july 15-16, 2012. [4]. c. k. babulal, p. s. kannan and j. maryanita, “a novel approach to determine static voltage stability limit and its improvement using tcsc and svc”, journal of energy & environment, vol. 5, may 2006. [5]. w. zhang, f. li, and l. m. tolbert , “optimal allocation of shunt dynamic varsource svc and statcom” a surveyelectrical and computer engineering, the university of tennessee. [6]. m. s. saad, and a. edris , “delaying instability and voltage collapse in power systems using svcs with washout filter-aided feedback”, american control conference, june 8-10, 2005. [7]. r.alammari, “the voltage collapse problem based on the power system loadability”, engineering journal of university of qatar, vol. 10, 1997. [8] .h. yonezawa , m. tsukada and j. “paserba,study of a statcom application for voltage stabilityevaluated by dynamic pv curves and time simulations” ,power engineering society winter meeting, conference , vol. 2, 23 -27 jan 2000. [9]. h. boroujeni, m.amani and m.abdollahi, “dynamic stability improvement by using statcom in a multi machine environment”, research journal of applied sciences, engineering and technology 4(18): 3505-3509, 2012. [10] . m .kamarposhti “ evaluation of static synchronous compensator in order to loading margin study in power system ” indian journal of science and technology vol. 3 no. 5 , issn: pp 09746846. (may 2010) . [11]. a. kazemi h.a. shayanfarm.anda. rafiee, “impact of statcom and opf on power system voltage stabilityusing modal analysis and quadratic programming” ,proceedings of the 12 th iranian electrical engineering conference , vol. 1, pp. 25-29, mashhad , may 11-13 , 2004 iran. [12] .c. r. “hemavathi,predicationof voltage stability by using modal analysis”, national conference on electrical sciences -2012 (nces-12). http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=6841 http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=6841 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 099 [13]. e. tobaji1, m. khaldi2 and d. fadel3 , “statcom control of ill-conditioned power systems using”, advance in electronic and electric engineering,, volume 3, number 3 ,pp . 311-320, india. 2013. [14]. p. bisen and a. shrivastava, “voltage level improvement of power system by the use of statcom & upfc with pss controller” ,international journal of electrical, electronics and computer engineering val 2(2): pp 117-126 (2013). [15] .h. marefatjou1, i. soltani2, “optimal placement of statcom to voltage stability improvement and reduce power losses by using qpso algorithm”, journal of science and engineering vol. 2 (2), pp 105-119,iran 2013. [16]. g. a. adepoju, , o.a. komolafe, “analysis and modelling of static synchronous compensator (statcom): a comparison of power injection and current injection models in power flow study”, international journal of advanced science and technology vol. 36, november, 2011. table (1): bus data information for isg bus no. bus name voltage (p.u.) angle (degree) generation load mw mvar mw mvar 1. musp 1.04 0.0 1.997795 1.166333 2. mmdh 1.015 0.0 690.1 0 000 0 3. bajp 1.02 0.0 406.0 0 124.8622 92.2467 4. bajg 1.02 0.0 590.458 0 0 0 5. krk4 1.017 0.0 239.87 0 129.8567 10.4896 6. musg 1.02 0.0 369.04 0 0 0 7. hdth 1.02 0.0 202.97 0 200.0540 50.612 8. qdsg 1.01 0.0 735.305 0 0 0 9. kazg 1.0096 0.0 207.583 0 200.0419 100.6579 10. hrtp 1.01 0.0 332.133 0 154.8291 72.1171 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 222 table (2): bus solution for isg bus no. voltage (p.u.) angle (degree) generation load mw mvar mw mvar 1. 1.04 0 679.69 2422.66 1.997795 1.166333 2. 1.015 8.4837 690.1 58.06 000 0 3. 1.02 5.7762 406.0 -35.98 124.8622 92.2467 4. 1.02 5.8258 590.458 -65.46 0 0 11. nsrp 1.02 0.0 775.0 0 422.8665 100.3219 12. dyl4 1.00 0.0 0 0 83.2415 21.1712 13. bgw4 1.00 0.0 0 0 576.031 302.4481 14. bgn4 1.00 0.0 0 0 412.8776 139.1261 15. bge4 1.00 0.0 0 0 849.0627 294.6579 16. qim4 1.00 0.0 0 0 109.8787 39.3182 17. bgc4 1.00 0.0 0 0 49.9449 181.4688 18. bgs4 1.00 0.0 0 0 0 0 19. amn4 1.015 0.0 184.518 0 126.5640 56.0014 20. msl4 1.00 0.0 0 0 649.2833 302.4481 21. bab4 1.00 0.0 0 0 307.9934 184.6695 22. kds4 1.00 0.0 0 0 213.0981 151.4458 23. kut4 1.00 0.0 0 0 259.7134 108.1756 24. amr4 1.00 0.0 0 0 311.0221 160.3709 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 222 5. 1.017 4.5233 239.87 -76.88 129.8567 10.4896 6. 1.02 0.2260 369.04 -2016.6 0 0 7. 1.02 1.9 202.97 -40.51 200.0540 50.612 8. 1.01 -0.8491 735.305 136.84 0 0 9. 1.0096 -3.4122 207.583 -4.77 200.0419 100.6579 10. 1.01 -4.0027 332.133 87.22 154.8291 72.1171 11. 1.02 -1.480 775.0 -48.14 422.8665 100.3219 12. 1.015 -1.3931 184.518 207.65 126.5640 56.0014 13. 1.0038 -0.8865 0 0 83.2415 21.1712 14. 1.0085 -1.1285 0 0 576.031 302.4481 15. 1.0086 -1.6927 0 0 412.8776 139.1261 16. 1.0163 0.4494 0 0 849.0627 294.6579 17. 1.0045 -0.8865 0 0 109.8787 39.3182 18. 1.0202 -0.8152 0 0 49.9449 181.4688 19. 1.0118 -0.9587 0 0 0 0 20. 1.0053 6.2414 0 0 649.2833 302.4481 21. 1.0334 -0.8086 0 0 307.9934 184.6695 22. 1.0274 -1.6149 0 0 213.0981 151.4458 23. 1.0018 -7.107 0 0 259.7134 108.1756 24. 0.9899 -8.048 0 0 311.0221 160.3709 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 220 table (3): eigenvalue and participation factor magnitude for isg bus number eigen value participation factor 13 2109.374 1.583*10 -12 14 906.961 1.146*10 -9 15 684.1398 1.050*10 -8 16 473.233 8.6997*10 -9 17 449.863 8.687*10 -21 18 119.394 1.168*10 -6 19 134.423 3.523*10 -6 20 130.824 1.379*10 -20 21 77.0474 3.334*10 -10 22 30.662 1.971*10 -10 23 224.595 7.685*10 -20 24 41.712 2.552*10 -19 figure. (1). statcom configuration ac system bus coupling transformer leakage reactance vdc cdc vsc al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 222 figure (2): model of statcom in load flow calculation figure (3): power flow solution by newton-raphson with statcom pi +jq-j qc statcom bus i jqc pi+jqi bus i start input system data form system admittance matrix form conventional jacobin matrix modify jacobin matrix and mismatch power equation update system bus bars voltages is the convergence output load flow results end yes no al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 222 . figure (4): configuration of the isg al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 222 figure (5): the participating factor profile for the minimum eigenvalues of the isg figure (6): voltage of all buses with and without statcom. 0.96 0.97 0.98 0.99 1 1.01 1.02 1.03 1.04 1.05 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 v o lt a g e s m a g n it u d e i n p .u bus number. without statcom with statcom effective of digital scanning system mechimesm on the laser guided unit (lgu) al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 53 analyzation the accepted and rejecteddisturbances by using vss techniques dr.fadhel abbas jumaa lecturer dep. engineering of technical electrical power technical college al – musayab e-mail:fadhelalsamir@yahoo.com abstract in this research the values of rejected and accepted (programmed) are compared to the variable control systems (vcs) by drawing curves and determine the values of the voltage switching surface system (vss), which is working under the external effects and connect in the parts of control structure (s1, s2).the analysis presented here in treating the question of changing the structure when a deterministic disturbance acts anywhere in the control system using (mat lab programs). an adaptive model reference algorithm in established to make the control system respond satisfactory or not there is a disturbance. in this system best responses are achieve by noting many information and factors like steady state error (s.s.e), order of control system, type of switching and also notes the logarithmic structure for vss voltages in case of input reference sources model to get best performance. تحليل االضطرابات المقبولة و المرفوضة باستخدام تقنيات الفولتيات المتغيرة للمنظومات د.فاضل عباس جمعة مدرس قسم هندسة تقنيات القدرة الكهربائية المسيب \التقنيةالكلية الملخص تم في هذا البحث مقارنة قيم االضظرابات المرفوضة والمقبولة )المبرمجة ( لمنظومات السيطرة المتغيرة المتغيرة من خالل رسم المنحنيات وتحديد قيم تقنية الفولتيات (vss)والتي تعمل بوجود التأثيرات .ومن خالل البرامج التي (s1,s2)اكيب أجزاء السيطرة المتغيرة للمنظومة الخارجية, كذلك قمنا بتعشيق تر كتبت بالمصفوفات المختبرية فان التحليل المقترح سوف يعالج المشاكل التي تظهر خالل تغير التراكيب في المنظومة عندما يدخل اضطراب منتظم في مواقع مختلفة من منظومة السيطرة. analyzation the accepted and rejecteddisturbances by using vss techniques 53 عشوائية المرغوب فيها والغير مرغوب بها والتي من كما شمل االختبارصنف محدد من االضطرابات ال خاللها تم الحصول على افضل النتائج المستجابة لها المنظومة باستخدام التعشيق بين وظائف المنظومة ( ووظيفة نظام السيطرة باستخدام تغذية مرجعية.vssذات الفولتيات المتغيرة ) معلومات وعوامل منها نسبة حالة الخطأ لتحقيق أفضل استجابة للمنظومة يجب مراعاة عدة (s.s.e نوع نظام السيطرة ,درجة الدالة ,نوع المفاتيح المستخدمة مع مالحظة التصميم,) mledonceeeeeeesource i pفي حالة نموذج مصدر اإلدخال للسيطرة ) svsاللوغارتميللفولتيات ( في مثل هكذا scieomrphوالتوافقيات)(لغرض زيادة أدائها ومعالجة االضطرابات الغير مرغوب بها منظومات . 1introduction. the involvement of voltage switching surface system (vss) in order to stabilize control system of second and higher order system has been investigated [buja, g.s, 1993].the theory of (vss), widely studied and directly applied to the design of mrac system [ambrosino,g,1982]. the advantage of this approach is that the transient response of the error during sliding motion can be prescribed in advance, but the controller structure requires the use of difference by using variable filter in the controller structure and introduce the so called (argument error signal) to derive the parameter adaptation law assuring the convergence of the error to zero [ambrosino, g, 1982, rebiai, s.e, 1998]. however more complete design method stability proof is associated with an (error model) in which the integral parameter adaptation law is used. the vss on the present with adaptive pole assignment control in the presence of uncertain non-minimum phase system affected by bonded disturbances; the control scheme proposed is characterized by a simple first-order fixed compensator introduced in parallel to the plant; with a set of a tunable state variable filters [bartolini,g, 2002]. the insensitive sliding mode offered by a vss makes it a wellknown solution to the problem of deterministic control of parameter uncertainties and rejects external disturbances [banks, s.p, 2008]. static vss algorithm can reject completely the disturbance only if the amplitude of the switching term; in the control (i/p) is larger than the amplitude of disturbance itself, and shows how it is possible by adding an integral term in the vss control algorithm to reach and remain in the sliding mode if the amplitude of the switching term is smaller than the amplitude of the disturbance [itkis, u, 1978] 2theory the main advantages of vss are the robustness to parameter variations and the in variance vss approaches may possess distinguished characteristics of disturbance rejection therefore; in the present work we are going to examine and illustrate the performance of one (vss) algorithm approach which has been presented in [yaz, e, 2003].when (vsc) algorithms with chattering reduction for the control of fractional armature controlled d.c motor with gear coupling. there are three altitudes a designer can adopt in regard to accommodating (coupling with) disturbances that arise in general control problems. in that case; disturbances are optimally accommodated when the controller is designed to exactly can out all effects of disturbances on system behavior. this is called (disturbance-absorbing); in fact be achieved by clever application of modern optimal control theory and leads to a verity of controller which is called (disturbance-utilization). in practical applications; the given design specifications al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 53 might dictate the use of a combination of the varieties of disturbances accommodating controllers; this leads to another variety of controller which is called (multi-mode disturbances accommodating controller) [johnson, c.d, 1997]. the kind of disturbances w (t) encounters in realistic control system designs can be classified into two broad categories: noise-type disturbances and disturbances with waveform structure. disturbance w (t) which possesses (waveform structure) exhibiting distinguishable waveforms patterns; can be mathematically model by semi-deterministic analytically expressions (linear equation) of the form: according to the equation (1) the (unknown) disturbance w(t) can be expressed at any moment (t), as some weighted linear combination of the known basis function f1(t) having unknown weighting coefficients c1(t) (where c1 may jump in value from time to time in a random piecewise constant fashion) [white, r.m, 2011]. several vss control algorithms have been proposed and studied in the literatures, the main idea of these algorithms is to use a feed forward action to compensate the known part of the system and then introduce a switching term in the control (i/p) in order to eliminate the undesired unknown disturbances. the application of external disturbances to the system gives rise to a study-state error (s.s.e) or (under damped self-sustained oscillations). in what follows the disturbances rejection capability of variable structure control system vss designed according to minimizing certain control area criterion will be analyzed whether the switching circuit designed with respect to certain reference control input responds adequately with respect to certain disturbance input or not [young, k.s, 2009]. 3-simulation, results and calculations the problem of robust stabilization of uncertain system can be solved by using several control approaches; adaptive control, optimal control and vss; vss approach allows total rejection of external disturbances. the search and application in the field of variable structure system (vsc) through vss has been maintained at a high level and dedicated to sliding mode control which matter reflects the interest of control theorists and practicing engineers. there are several commonly used system configuration by control system performance in figures 1-a, b and figures 2-a, b [m.d.desai, 2012]. control system performance may be improved by feeding back the state variables through constant gain. in fact the majority of the design techniques in modern control theory are based on the state negative feedback (-f.b) configuration with pid control and rate negative feedback (-f.b) control are all special cases of the state feedback control with and without any factor disturbances. if n(t) has to be in the input (i/p) of the system then g(s)1=1; at (o/p) then g(s)2=1;note the negative sign [n(t)] which is used for the simplicity of the mathematical derivation. the closed loop transfer function between the error signal e(t) and the disturbance signal n(t)is:[banks, s.p, 2008]. variable structure control (vsc) for a second order control system is shown in figure 3 analyzation the accepted and rejecteddisturbances by using vss techniques 53 the occurrence of disturbance in certain locations in the control plant causes mainly the partitioning of the system; so the control plant may require certain sequence of switching which is not the same as it is required for normal ( i/p) control. consider the second order vss control system by using variation with disturbance for types of two structures vss as shown in figure 4. the main effect of external disturbances is to impose a steady state error (s.s.e); theoretically vss represents one of the powerful control tools to eliminate disturbance effects on the system. in fact, the simulation cases show that a complete rejection of disturbance effects cannot be achieved through the proposed vss design, this happens if the structure being connected is under damped characteristics and no switching conditions are satisfied; see figures 5 (a) & (b) represented a computer simulation by (matlab lang) to illustrate the vss capabilities to eliminate the stochastic disturbance effects when error against time through many variables by card interference control system. we must pay attention to the selection of the controller parameter, such that to obtain non sluggish over damped structure and achieve increased number of switching through validating switching function. simulation results summarize that the (s.s.e) for the following cases: 1-disturbance at input when g(s) 1=1. 2-disturbance at output state fb. 3-selection of switching conditions and sequence mode are not matched. the results of investigating the effect of external disturbances imposed on the (o/p state f.b) in first and second derivatives are displayed in figures 6 & 7. it can be seen that vss can not eliminate the types of rejection disturbances and the error response follows one structure and switching does not take place even when switching occurs; unacceptable performance results. when both reference (i/p) and disturbance are present in a linear system, each can be treated independently and the outputs corresponding to each are added to give the complete (o/p), examining the effect of the disturbance n(s)assume that the system is at rest initially, then calculate the error response en(s) to the disturbance only. this response can be found from on the other hand, in considering the response to the reference input r(s), assume that disturbance is zero. then the error response er(s)to the reference input r(s) can be obtained from: the response to the simultaneous application of the reference (i/p) and disturbance can be obtained by adding the two individual responses, in other words the response e(s) due to effect application of the reference (i/p) r(s)and disturbance n(s)is given by al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 53 4-conclusions these points summarize the following conclusions 1-investigating vss ability to stands stochastic disturbance of defined statistical c/cs by two structure design. 2-it is shown that vss cannot eliminate the (s.s.e) in certain cases of deterministic disturbance in similar nature as that in normal control operation 3-analysis and mathematical formulation improve output state feedback by a logarithmic response against disturbance. 5-reference ambrosino, g. ,celetano,g. “variable structure model reference adaptive controller system” international journal of control (ijc); vol.9; no. 10; (1982). banks, s.p, “control system engineering; modeling and simulation; control theory and microprocessor implementation”; prentice-hall international, ch.6,pp1023; (2008). bartolini,g. and ferrara, a. “variable structure approach to the pole assignment control of non-minimum phase system” proceedings of ieee transaction on automatic control, vol.76; no. 3; march, (2002). buja, g.s and souliaev.a “design of sliding mode controller for vss in the disturbance rejection” ieee; vol.32, no.3, april (1993). espana,m.d,ortega,r.s and espino,j.j."variable structure system with chattering reduction: amicroprocesser based design",automatic,vol.6,no3:(2010). itkis, u and jon willy “control system of variable structure” ch.7, pp102; (1978). johnson, c.d; “theory of disturbance-accommodating controllers” control and dynamic system: advances in theory and application, academic press, inc. (1997). m.d.desai, “control system components” ch11, p398; (2012). rebiai, s.e and zinober, a.e “stabilization of uncertain distributed parameter system” (ijc) vol. 57; no. 5; (1998). white, r.m “a sensor classification scheme” ieee trans. altrasonics, ferroelectrics and frequency control, march; (2011). yaz, e and azemi, a “variable structure observer with boundary-layer for correlated noise /disturbance models and disturbance minimization” ijc, vol.23, no. 5, p.284, (2003). young, k.s and cken, y.p “anew controllers design for manipulators using the theory of vsc”, ieee transactions on automatic control, vol.6, no.7; july (2009). analyzation the accepted and rejecteddisturbances by using vss techniques 04 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 04 f ig u r e 5 (a ) a n d (b ) c o m p a re v s s p e rfo rm a n c e w ith sto c h a stic d istu rb a n c e (a ) (b ) analyzation the accepted and rejecteddisturbances by using vss techniques 04 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 317 x-ray study of nanosized copper powder produced by sonoelectrodeposition process mohammed jasimkadhim adnan s. jabur heider yasser thamir alyasiri department of production college of engineering, college of engineering, engineering and metallurgy university, basra-iraq. al-qadisiyah university university of technology, baghdad-iraq. dr.heider.alyasiri@gmail.com received 10 november 2014 accepted 18 may 2015 abstract electrodeposition process coupled with ultrasonic vibration (sonoelectrodeposition) was used to deposit nanosized copper powder from acidic solution of copper sulphate. thecathodic current density and the amplitude of vibration used are 37.5 ma/cm 2 and 35% from the maximum capacity of vibration respectively. purity, morphology and size of the nanosized powder were studied. the xrd studies also reported.the copper powderhas a high purity with mean size of particles about 52 nanometer. xrd analysis confirms that the crystals, sizes are in nanosized range. keywords: electrodeposition, ultrasonic, particle size, morphology, sem, eds, xrd. 1. introduction nanostructured materials (including metals) get an increasing importance in various branches oftechniques and science owing to their unique mechanical, magnetic, optical, thermoelectric and other properties [1,2]. much attention has been paid to metalnanoparticles which exhibit novel chemical and physicalproperties due to their extremely small dimensionsand high specific surface area.nanoparticles have properties different than those from bulk materials due todrastic reduction of particle size [3,4]. nowadays researches on synthesis of metal nanoparticles arelargely studied their special properties; many methods have been developed for the fabrication of metal nanoparticles [5]. among various metal particles, copper nanoparticleshave attracted considerable attention because of itsunique catalytic, optical and electrical conductingproperties [6-9].several methods have beendeveloped for the preparation of coppernanoparticles, including wet chemical reduction [10,11], microwavereduction [12], metal vapor synthesis [13], radiationmethods [14], chemical reduction in organic template [15],wire explosion [16], andelectrodeposition technique [17-19]. electrodeposition coupled with ultrasonic vibration was also used to synthesize copper nanostructures [20,21]. it requires careful selection of effective processingparameters. sonoelectrochemistry is the coupling of ultrasonic vibration to an electrochemical system. the term ‘sonoelectrochemistry’ appeared at 1990 [22]. recently there is a growing interest of the application of mailto:dr.heider.alyasiri@gmail.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 318 the sonoelectrochemistry in the preparation of nanopowders [23,24]. sonoelectrochemistry method is a simple environmental friendly and cost effectiveness method used to produce metallic nanosized materials compared to most of other methods including radiation, thermal decomposition, vapor deposition, reduction in microemulsions and chemical reduction [25]. 2. experimental procedures in this study, a nanosized copper powder was electrodeposited from acidic copper sulphate solution in electrodeposition cell under the effect of ultrasonic vibration (20 khz) as shown in figure 1. the vibrator horn was immersed inside solution between copper plates of cathode and anode. the amplitude of vibration was 35% from the maximum capacity of vibration. the catholic current density was37.5 ma/cm 2 .after deposition, the copper was collected and washed several times with deionized water to remove impurities and then washed several times with ethanol to remove the water of washing. an estimation of the impurity level was performed by x-ray energy dispersive spectroscopy (eds) system (energy dispersive si(li) x-ray detector) connected with the scanning electron microscope. satw window was used for chemical analysis of microscopic volumes for all elements with atomic number of more than z = 4 (be), oxford instruments analytical ltd england. the sample for test was dispersed in ethanol and dropped on aluminum foil placed on aluminum stump. the surface morphology of copper particles was investigatedby scanning electron microscopy. max. magnification ~ 50.000x. five axis motorized high geared stage in extra-large chamber as standard. accelerating voltage range 200v to 30000v, model: 1450 vp leo (variable pressure operation), leo electron microscopy ltd, england. to estimate the size of the particles, the product which is already agglomerated and settled in bottom of storing cans should be re-dispersed using ultrasonic bath. alcohol containing well dispersed powder was entered to laser diffraction device (vasco-nano particle size analyzer, cordouan technologies, france)to examine the size of copper particles. samples of copper nano-powder were analyzed using xrd analysis by an x-ray diffractometer. xrd analysis was used to test the existing phases and parameters of unit cell, through peak indexing process. size of the crystalline phase was also determined using xrd data. data was taken for the 2θ range of 20 to 90 degrees with a step of 0.018 degree. 3. results and discussion the qualitative eds analysis figure 2 shows that the product is a pure copper element. the peak of carbon is related to residual ethanol. the peak of aluminum is related to aluminum foil and to the aluminum stump.this analysis confirms the product is a pure copper element. the morphology of the powder is shown in figure 3. the morphologies of nanosized copper powder are treelike through irregular, angular, and rounded.the size distribution of the copper particles is shown in figure 4 and the mean size of the tested sample is about 52 nanometer. figure 5 shows the present three peaks (from left to right): peak1, peak2, and peak3, assigned to 2θ values of 43.379°, 50.399, and 74.321° respectively, using bragg’s law (1). n λ = 2d sin θ (1) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 319 to find the d-spacing of each peak. peak1: 2θ = 43.379°, θ = 21.6895°, d-spacing (d1) = 0.2085 nm. peak2: 2θ = 50.399°, θ = 25.1995°, d-spacing (d2) = 0.1809 nm. peak3: 2θ = 74.321°, θ = 37.1605°, d-spacing (d3) = 0.1275 nm. these calculated values of d-spacing were used to find the corresponding miller indices (hkl) of diffraction plane of each peak (table 1). the dividing constant is equal to the difference between first two ( ), and the results of ( ) column need to be integer values. these peaks and their corresponding plane are shown in table 2 and they are almost identical in comparison to the standard diffraction peaks of copper (jcpds, file no. 04-0836). the calculated inter planar spacing d-spacing values were used to prove the element is copper, but anyway these values are not fully-identical to (jcpds, file no. 04-0836) which is also not fully identical to ideal values of d-spacing. ideal values can be calculated using formula (2). = (2) where a for copper = 0.3615 nm, and using d-spacing value in bragg’s law (1) to calculate the ideal values of diffraction angles 2θ. table 3 lists the experimental and ideal values of inter planar spacing and diffraction angle 2θ of (111, 200 and 220) diffraction planes. average crystal size (d) of the tested particles can be estimated using debye-scherrer formula: (3) where: λ: x-ray wave length = 0.1541 nm. : full width at half maximum (fwhm) of the diffraction peak. θ: diffraction angle of the peak. for (111) plane, diffraction angle of the peak1,θ = 21.6895° and = 0.284° = = 0.00496 radians therefore, = 30.1 nm according to xrd results (figure 5), three peaks at 2θ values of 43.379°, 50.399°, and 74.321° respectively corresponding to (111), (200) and (220)planes of copper have been observed and al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 320 compared with the jcpds, copper file no. 04–0836. the produced nanoparticles are a single phase of a pure copper element with fcc crystal structure. the crystal size was measured using the debyescherrer formula for x-ray crystal size determination and it was found to be 30 nanometer. this gives conformation that the sizes of particles are in nanosized range. 4. conclusions 1electrodeposition process under the effect of ultrasonic vibration (sonoelectrodeposition) was successfully used to produce nanosized copper powder. 2the purity of copper is approved. 3the morphology of the powder is treelike through irregular, angular, barlike, and rounded. 4the existing phase was fcc crystalline copper and the crystal size through nano range.\ 5. references [1] d.g. allis, j.t. spenser, “nanostructural architectures from molecularbuilding blocks”, handbook of nanoscience engineering and technology,crc press llc, 2003. [2] c.l. peterson, “nanotechnology: from feynman to the grand challenge of molecular manufacturing”, ieee technology and society magazine, winter (2004)9-15. [3] c.p. poole jr, f.j. owens, “introduction to nanotechnology”, johnwiley& sons inc., 2003. [4] j.h. fender, “nanoparticles and nanostructured films”, wiley-vchverlag gmbh, 1998. [5] c.c. koch, “nanostructured materials: processing, properties andapplications”, william andrew inc., 2007. [6] s. kapoor, t. mukherjee, "photochemical formation of coppernanoparticles in poly(nvinylpyrrolidone)", chemical physics letters,370(2003)83–87. [7] s. chen, j.m. sommers, "alkanethiolate-protected coppernanoparticles: spectroscopy, electrochemistry, and solid-statemorphological evolution ", j. phys. chem. b, 105(2001)8816-8820. [8] t.-y. dong, h.-h. wu, m.-c. lin, "superlattice of octanethiol-protected copper nanoparticles", langmuir, 22(2006)6754-6756. [9] m. blosi, s. albonetti, m. dondi, c. martelli, g. baldi,"microwaveassistedpolyol synthesis of cu nanoparticles", j. nanoparticles research,13(2011)127-138. [10] h.h. huang, f.q. yan, y.m. kek, c.h. chew, g.q. xu, w. ji, p.s.oh, s.h. tang, "synthesis, characterization, and nonlinear opticalproperties of copper nanoparticles", langmuir, 13(1997)172175. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 321 [11] h.h. paradies, m. thies, u. hinze, "template mineralization ofordered nanomaterials of metallic copper and copper-i-oxides in thepresence of double chained cationic lipids-(iii)", the rigaku journal,17(2)(2000)9-19. [12] r. makinen, h. sillanpaa1, k. ostman, v. palukuru, v. pynttari, t. kanerva, j. hag-berg, t. lepisto, h. jantunen, m. yang, p.b. laxton, h. arimura, r. ronkka “wide-band electrical characterization of printable nano-particle copper conductors”, asia pacific microwave conference (apmc), 2009., ieee: (apmc 2009)2455-2458. [13] m.k. patel, b.j. nagare, d.m. bagul, s.k. haram, d.c. kothari , "controlled synthesis of cu nanoparticles in fused silica and bk7 glasses using ion beam induced defects", surface & coatings technology, 196(2005)96-99. [14] q. chen, x. shen, h. gao, "formation of nanoparticles in water-inoil microemulsions controlled by the yield of hydrated electron: the controlled reduction of cu2+", journal of colloid and interface science, 308(2007)491-499. [15] h. zhu, g. john, b. wei, "synthesis of assembled copper nanoparticles from copper-chelating glycolipid nanotubes", chemical physics letters, 405(2005)49-52. [16] p.k. dash, y. balto, "generation of nano-copper particles through wire explosion method and its characterization", research journal of nanoscience and nanotechnology, 1(1)(2011)25-33. [17] s. ulubay, z. dursun, "cu nanoparticles incorporated polypyrrole modified gce for sensitive simultaneous determination of dopamine and uric acid", talanta, 80(2010)1461-1466. [18] y. li, j. sun, c. bian, j. tong, s. xia, "electrodeposition of copper nano-clusters at a platinum microelectrode for trace nitrate determination", procedia engineering 5(2010)339-342. [19] j. mathur, m. gupta, “effect of electrodeposition parameters on morphology of copper thin films”, iosr journal of engineering, 3(2013)55-61. [20] b. hong, c.h. jiang, x.j. wang, “effects of ultrasound on morphology of copper electrodeposited on titanium in aqueous and organic solutions”, materials transactions, 49(2)(2008)275-277. [21] s. coleman, s. roy, “effect of ultrasound on mass transfer during electrodeposition for electrodes separated by a narrow gap”, chemical engineering science, 113(2014)35-44. [22] t.j. mason, j.p. lorimer, “applied sonochemistry”, wiley-vch verlag gmbh, weinheim, 2002. [23] s. kumbhat, “potentialities of power ultrasound in electrochemistry: an overview”, bull. electrochem., 16(2000)29-32. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 322 [24] j.l. delplancke, j. dille, j. reisse, g.j. long, a. mohan, f. grandjean, “magnetic nanopowders: ultrasound assisted electrochemical preparation and properties”, chem. mater., 12(2000)946–955. [25] v. zin, b.g. pollet, m. dabala, “sonoelectrochemical (20 khz) production of platinum nanoparticles from aqueous solution”, electrochim. acta, 54(2009)7201-7206. table (1): peak indexing of tested sample. table (2): diffraction angles of tested sample and standard diffraction angles of copper. table (3): the experimental and ideal values of inter planar spacing and diffraction angle. peak no. 2θ (degrees) d-spacing (nm) remarks + + plane of diffraction 1 43.379 0.2085 230.03 3.05 + + =3 111 2 50.399 0.1809 305.58 4.05 +0+0=4 200 3 74.321 0.1275 615.15 8.14 + +0=8 220 peak no. diffraction plane experimental diffraction angle 2θ (degrees) standard diffraction angle 2θ (degrees) of copper jcpds, file no. 04-0836 1 111 43.379 43.297 2 200 50.399 50.433 3 220 74.321 74.130 diffraction plane ideal d-spacing, nm experimental dspacing, nm ideal diffraction angle 2θ, degree experimental diffraction angle 2θ, degree 111 0.2087 0.2085 43.3314 43.379 200 .01808 0.1809 50.4484 50.399 220 0.1278 0.1275 74.1551 74.321 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 323 figure (1): the electrodeposition cell setup. figure (2): eds analysis of nanosized copper powder. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 324 figure (3): the morphology of the nanosized copper powder. figure (4): size distribution of nanosized copper powder. ` al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 325 figure (5): xrd of the sample. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 127 tumadhir merawi borhan department of civil engineering, al-qadisiyah university, p.o. box 1881, ad diwaniyah, iraq tumadhir_borhan@qadissuni.edu.iq abstract an attempt to determine an easy and accurate method to predict the thermal conductivity of concrete is presented in this paper. the new method is based on the heat transfer test results and the finite element software package abaqus. the boundary condition for this model was the temperature profile of the exposed side of the specimen which was taken from the heat transfer tests. the values of the thermal conductivity that give the closed agreement curve for the unexposed surface temperature profile were recorded for a different temperature levels. this method can be adopted to compare the value of the thermal conductivity of any type of concrete with other concrete as an easy and fast alternative method to the standard test methods. keywords: concrete, thermal conductivity, heat transfer test, abaqus model. abaqusتقدير معامل الموصلية الحرارية للخرسانة باستخدام برنامج الخالصة لتقدير معامل الموصلية الحرارية للخرسانة . تستند هذه الطريقة على ودقيقة يقدم هذا البحث محاولة جديدة اليجاد طريقة سهلة . ان المحددات لطريقة العناصر abaqusيقة التحليل بالعناصر المحددة باستخدام البرنامج نتائج اختبار انتقال الحرارة وعلى طر سجلت قيم الموصلية . المحددة هي التغير الحراري مع الزمن للسطح المعرض للحرارة بصورة مباشرة والسطح الغير معرض للحرارة سطح الغير معرض للحرارة بصورة مباشرة. اظهرت النتائج انه لل درجة الحرارةمنحنى التغير بتوافق لالحرارية التي تعطي أفضل باالمكان اعتماد هذه الطريقة للحصول على قيمة تقريبية لمعامل الموصلية الحرارية بصورة سريعة ودقة الي نوع من انواع قياسية للفحص.الخرسانة واالستفادة منها للمقارنة مع انواع اخرى من الخرسانة في حالة تعذر اجراء الطريقة ال introduction thermal conductivity is a measurement of the ability of the material to conduct heat. the coefficient of thermal conductivity of concrete depends on the moisture content, type of aggregate, porosity, density, presence of fibre and temperature. two techniques are commonly used to measure the thermal properties of concrete; these are the steady state method and the transient method. the principles of the steady state technique are based on creating a steady temperature gradient across a known thickness specimen by controlling the heat flow prediction of the thermal conductivity of concrete using abaqus model al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 128 from one side to another. the determination of the thermal conductivity can be obtained by applying fourier’s law in one dimension. the most common methods used are the guarded hot plate and the heat flow meter method (franco 2007). these methods, however, require a long time to establish the steady state temperature gradient across the specimen where the gradient is required to be large. the size of the specimen is also required to be large. another problem related to this method is a potentially great influence of thermal contact resistances between the sample and other elements of the measurement system on the results. this problem is particularly significant if the contact surfaces are rough and filled with air (nenad stepanić 2009) on the other hand, transient techniques perform a measurement during the process of heating. the advantage is that these may be made relatively quickly. the most common method used is the transient plane source method which is also called the hot disk method. a plane sensor, a special mathematical model describing the heat conductivity, combined with precise electronics, enables the method to be used to measure thermal transport properties. the disadvantage is that the mathematical analysis of the data is in general more difficult than the steady state methods. a comparison study showed that over a large range of conductivities (1.4 to ∼5 w/ m. k) and rock types there is almost no difference between the results obtained from using both methods (sass et al. 1984). a number of researchers have attempted to predict the thermal conductivity of concrete using theoretical models (choktaweekarn et al.2009, kim et al. 2003, khan 2002). these models take into consideration the thermal conductivity of each ingredient of concrete, the moisture content, porosity, and other factors. however, they are not suitable for some types of concrete, such as fibre reinforced concrete, nor for all environmental conditions such as fire condition. an easy and accurate method to determine the thermal conductivity of concrete still needs further research. this study presented a new attempt to predict the thermal conductivity of concrete. the new method is a combination of a simple heat transfer test, conducted by borhan (borhan 2012), and the finite element software package abaqus. the results from abaqus model was validated against borhan’s experimental results and discussed. experimental work the results from the developed heat transfer tests conducted by borhan (borhan 2012) were used in the author’s study. borhan’s mixes were produced from a concrete reinforced with different volume fractions of basalt fibre (0, 0.1, 0.3, and 0.5% by total mix volume). the binder consists of ordinary portland cement and metakaolin (china clay) (cc) (10% by weight of cement was added to cement). the coarse aggregate (ca) used in this study was limestone of 10mm maximum size and natural sand was used as a fine aggregate. the superplasticizer (sp) used was a sulphonated formaldehyde condensate (daracem sp6). the optimum dosage of the sp, which gives 50 mm slump, was chosen by doing a trial mixes for concrete mixture which contains 0.5% basalt fibre. the mix proportions for all mixes were 1:1.75:3.5 (cement: sand: coarse aggregate) by weight with (0.55) water to binder ratio. the control mix (f0) details is shown in table 1, the other mixes are marked as f1, f3, f5 for 0.1, 0.3 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 129 and 0.5% (by total mix volume) basalt fibre respectively. the physical and the chemical properties of the materials used in borhan’s study were presented in table 2. a heat transfer test was developed by borhan (borhan 2012) to measure the heat transfer through the thickness of concrete specimen (figure 1). the test procedure utilizes a standard kiln with automatic temperature control. small specimens (300x100x25) mm, from different mixes, were placed on the top of the kiln and insulated from the other directions (figure 1). the temperature was raised to 600 o c at a rate of 5 o c/min. thermocouples (type k) were used to record the temperature of the top and the bottom surfaces of the specimens (one thermocouple for each surface). the thermocouples were adhered at the centre of the two surfaces using a special type of glue (thermo –glue). the differential temperature between the outside and the inside faces of the specimen was calculated. the temperature differencetime history was plotted for each mix (figure 4). prediction of the thermal conductivity the finite element programme abaqus was adopted to predict an approximate value for the thermal conductivity (tc) together with the heat transfer test. the geometry of the specimen for the heat transfer test was modelled (figure 2). 20-node quadratic heat transfer brick elements (dc3d20) were used. the boundary condition for this model was the temperature profile for the exposed side of the specimen which was taken from the heat transfer test. the density for each mix was taken from the unit weight test results (borhan 2012) (table 3) . the data of the specific heat (sh) was used according to bsen1992-1-2 (bsen1992:1-2 2004) for normal weight concrete (nws). the recorded moisture content of the specimens was between 3 to 5% (borhan 2012). to find the suitable range of the variations in the analysis of the thermal conductivity and the specific heat values in the model that can effect the results, a sensitivity test was carried out to show the differences in the results when the values of the thermal conductivity and the specific heat changed above or below the recorded values by 0.1 and 0.2 w/m.k for the thermal conductivity and 100 j/kg. o c for the specific heat (figure 3). abaqus heat transfer model parameters (the film coefficient (h) and the sink temperature) used in this model were 25 w/m 2 k and 20 o c respectively for unexposed side and 25 w/m 2 k and 1 for the exposed side (with temperatures amplitude recorded by the thermocouples). the specific heat was modelled as temperature-dependent properties and the data according to the bsen1992-1-2, at moisture content 3%, were adopted for the control mix to start with (table 4). by iteration technique , following the heat transfer test results indication as a guide, the values of the thermal conductivity that give the closed agreement curve for the unexposed surface temperature profile were recorded for a different temperature levels and for nearest 0.05 w/m.k (figure 4 and table 5). from figure 5 it can be seen that increasing basalt fibre content results in decreasing the thermal conductivity of concrete at all temperature levels. this mainly due to the nature of the basalt rocks, which intern leads to the volumetric stability of basalt fibres which confirms higher resistance against high temperature exposure (sim et al. 2005). according to the data provided by bsen1992-1-2 (bsen1992:1-2 2004) for normal weight concrete (nwc), high strength concrete (hsc) and lightweight concrete (lwc), with increasing the temperature, the thermal conductivity of concrete decreases and it also depends on the type of concrete as shown in figure 6, which confirms the results obtained in this study. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 130 the results show that this method can give approximate values for the thermal conductivity (±0.05) and the specific heat that can be used to model different types of concrete. however, further experimental work is needed to compare the results from a standard thermal conductivity test with the results from abaqus model. conclusion abaqus with the heat transfer tests were used to predict an approximate value for the thermal conductivity. this method can be useful to compare the value of the thermal conductivity of different types of concrete as an easy and fast alternative method to the standard test methods. further research is needed to develop this model by conducting standard tests to validate abaqus model. references borhan, t. m. (2012) properties of glass concrete reinforced with short basalt fibre. materials & design, 42, 265-271. bsen1992:1-2. 2004. eurocode 2, design of concrete structures. general rules structural fire design. british standards. choktaweekarn, p., saengsoy, w. & tangtermsirikul, s., (2009) a model for predicting thermal conductivity of concrete. magazine of concrete research, 61, 271-280. franco, a. (2007) an apparatus for the routine measurement of thermal conductivity of materials for building application based on a transient hot-wire method. applied thermal engineering, 27, 2495-2504. khan, m. (2002) factors affecting the thermal properties of concrete and applicability of its prediction models. building and environment, 37, 607-614. kim, k.-h., jeon, s.-e., kim, j.-k., & yang, s., (2003) an experimental study on thermal conductivity of concrete. cement and concrete research, 33, 363-371. nenad stepanić, a., nenad milošević (2009) correction on the influence of thermal contact resistance in thermal conductivity measurements using the guarded hot plate method. serbian journal of electrical engineering, 6, 479-488. sass, j. h., stone, c., & munroe, r. j., (1984) thermal conductivity determinations on solid rock — a comparison between a steady-state divided-bar apparatus and a commercial transient linesource device. journal of volcanology and geothermal research, 20, 145-153. sim, j., c. park & d. moon (2005) characteristics of basalt fiber as a strengthening material for concrete structures. composites part b: engineering, 36, 504-512. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 131 table 1: control mix details ingredie nt ce ment kg/ m 3 w ater k g/m 3 sa nd kg/ m 3 c a k g/m 3 bas alt kg/m 3 s p m l c c k g/m 3 content (f0) 400 2 42 700 1 400 0 4 000 40 portland cement metakaolin superplasticizer basalt fibre property % property property property sio2 31.135 colour white appearance dark brown liquid density of unsized filament matl 2.67kg/dm3 al2o3 10.29 iso brightness >82.5 air entrainment 1% 2% moisture content of basaltic rock 0.1% fe2o3 4.295 -2µ (mass%) >60 chloride content nil melting point 1350°c cao 48.5 +325 mesh (mass%) <0.03 freezing point 0°c filament breaking load > 85 67cn/tex mgo 2.27 moisture (mass%) <1 elongation at break 2.8% so3 2.49 aerated powder density (kg/m3) 320 e-modulus 84 gpa k2o 0.835 tapped powder density (kg/m3) 620 continuous max temperature -250°c to 550°c 1200°c fire barrier tio2 surface area (m2/g) 14 na2o 0.22 pozzolanic reactivity (mg ca(oh)2/g) >950 eq na2o 0.765 l.o.i 1.98 other table2: chemical and some physical properties of the materials used 1 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 132 table (3) the density value for each mix (borhan 2012) table (4) specific heat value (abaqus) mix specific heat j/kg. o c 20c o 100c o 150c o 200c o 400c o 600c o f0 1000 1000 2020 2020 1100 1100 f1 1000 1000 2020 2020 2020 2020 f3 1000 1000 2020 2020 2020 2020 f5 1000 1000 2020 2020 2020 2020 table (5) thermal conductivity values (abaqus) mix thermal conductivity (w/m.k) 60c o 100c o 350c o 600c o f0 1.15 0.90 0.85 0.65 f1 1.10 0.85 0.80 0.60 f3 1.10 0.80 0.65 0.55 specime n mark. fibre% by vol. density (kg/m 3 ) f0 0 2418 f1 0.1 2415 f3 0.3 2412 f5 0.5 2410 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 133 f5 0.90 0.60 0.55 0.50 figure 1 heat transfer test figure 2 the abaqus model heat source insul ator speci men thermocouple s 300 mm 2 5 mm 100 mm al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 134 a) increasing and decreasing tc with increasing and decreasing sh b) increasing tc value with sh constant c) increasing and decreasing sh value with tc constant figure 3 prediction of tc and sh different cases al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 135 figure 4 prediction of tc (best curve value) for different mixes figure 5 thermal conductivity vs. temperature (abaqus) f 1 f 3 f 5 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 136 0 0.4 0.8 1.2 1.6 2 0 200 400 600 800 1000 1200 temperature [ o c] thermal conductivity [w/m k] nwc & hsc upper limit nwc & hsc lower limit lwc figure 6 thermal conductivity of different type of concrete verse temperatureaccording to bsen 1994-1-2. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 176 effect of high temperature on some properties of light weight concrete mr. haider m. al-baghdadi department of civil engineering. college of eng. babylon university. hdr_eng@yahoo.com received 28 january 2014 accepted 17 march 2014 abstract in this study, effect of high temperature on the compressive and flexural strength of concrete used crushed clay brick as coarse aggregate were studied and compared the results with concrete containing normal coarse aggregate as a control mix. the replacement of normal coarse aggregates in concrete mixes was done at 0%, 50% and 100% by volume for concrete mixes with crushed clay brick as coarse aggregate. concrete specimens were heated up to temperatures20 o c, 100 o c, 200 o c, 300 o c, 400 o c and 500 o c. samples were allowed to cool down naturally to room temperature. after that, the maximum compressive and flexural strength were evaluated for each temperature above. three samples were tested for each temperature. the compressive and flexural strength of concrete containing 100% of crushed clay brick as vcoarse aggregate gradually decreased (small loss) for all temperature increments compared with other two concrete mixes used (0% and 50%) by volume of crushed clay brick as coarse aggregate. however replacing 50% of normal aggregates with lightweight aggregates (crushed clay brick) by volume did not have a significant effect on the compressive and flexural residual strengths. keywords: crushed clay brick, compressive, flexural strength, lightweight aggregates, temperature. تأثير درجات الحرارة العالية على بعض خواص الخرسانة الخفيفة الخالصة: في هذا البحث تم دراسة خواص الخرسانة الخفيفة )مقاومة األنضغاط و مقاومة الكسر( التي تستخدم مخلفات معامل الطابوق درجات الحرارة العالية و مقارنتها مع خواص الخرسانة )خلطة مرجعية( التي تستعمل )كسر الطابوق الطيني( كركام خشن تحت تأثير % . تم تعريض 055% و 05الركام الخشن العادي. حيث تم استبدال الركام الخشن العادي بكسر الطابوق الطيني بنسب حجمية درجة سيليزية و تم تبريد النماذج بصورة طبيعية (055و 055, 055, 055, 100,20النماذج الخرسانية إلى درجات حرارة بمقدار ) لكل درجة حرارة كما في ذكر أعاله, حيث تم إلى درجة حرارة الغرفة. بعد ذلك تم فحص مقاومة االنضغاط و مقاومة الكسر للنماذج ضغاط و مقاومة الكسر فحص ثالث نماذج خرسانية لكل درجة حرارة. حيث تم مالحظة بوجود انخفاض تدريجي قليل في مقاومة األن % مقارنة مع الخرسانة التي تستعمل الركام الخفيف )كسر الطابوق الطيني( 055لخرسانة تستعمل ركام خشن)كسر الطابوق( بنسبة %( في جميع درجات الحرارة المقترحة في هذا البحث. 05% و 5بنسب ) al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 177 1. introduction the density of lightweight concrete is approximately 80 percent that of normal weight concrete. this lower density creates opportunities for cost savings in both the design and construction phases. the lower dead loads may allow larger beam spacing and smaller loads being transmitted to the substructure and the foundation with resultant saving in support costs.[a. m. neville, 2000] under high temperature effect, chemical composition, physical structure and moisture content of concrete changes. these changes are primarily observed at the cement paste and then at the aggregates as well. heating to high temperatures causes the dehydration of hardened cement paste and conversion of calcium hydroxide into calcium oxide in which chemically bound water is gradually released to become free water. aggregates also lose their evaporable water and hydrous aggregates dehydrate at high temperatures, and undergo crystalline transformation accompanied by a significant volume expansion temperature [ahmet b. kizilkanat, nabi y., nihat k., 2013]. it was observed that light weight concrete properties were deteriorated at 150 c˚ and the specimens began to lose some of their initial strengths at this temperature. though a considerable strength lose was not seen between 150-300˚ c, all types of concrete mixture continued to lose their compressive strength after 300˚c, and it was found that the heating duration does not affect the strength loss significantly.[a ferhat bingol & rustem gul, 2004]. but the [bazant 1996] observed that the duration of the exposure affects the loss of the strength considerably as well. when the duration of the exposure is more than 1 hour, the concrete loses its strength significantly and the most significant strength loss happens when the exposure is between 1 and 2 hours. light weight concretes with densities of less than 2000kg/m 3 can be made with an crushed clay brick (waste of local clay brick manufactory) as light weight aggregate. the highest compressive strength obtained was 56.4mpa at 90 days at a cementitious content of 600kg/m 3 . the highest splitting tensile strength achieved was 4.0mpa at 28 days [h.m.albaghdadi 2010]. different types of aggregates have various processes happening under high temperature. the common of aggregates have a tendency to be more or less stable until the temperature is about 500 o c. for the nonsiliceous aggregates, the temperature when reactions like transformation and decomposition will start is at about 600 o c [harmathy & aleen 1973]. at temperatures between 600 o c and 900 o c, the chemical and physical changes happen not only to aggregates, but to hardened cement paste as well. when dehydration of hardened cement paste takes place, it changes porosity and water evaporates from aggregates [bazant 1996]. the duration of the exposure affects the loss of the strength considerably as well. when the duration of the exposure is more than 1 hour, the concrete loses its strength significantly and the most significant strength loss happens when the exposure is between 1 and 2 hours. after the first hour of expo-sure, residual strengths of the concrete are approximately 80, 70, 60 and 30% at heating correspondingly to 200, 400, 600, 800 o c. after two hours or more, residual strengths decrease to 70, 60, 45 and 25 % at 200, 400, 600, 800 o c [bazant 1996]. [peng et al. 2006] was concluded that when the concrete cools down with a rapid change of temperature under cooling in water or spraying water for more than 30 min, it experiences ‘thermal shock’ and severe damage. when concrete is exposed to a temperature of 200 o c and cooled down under natural conditions, its compressive strength can be higher than when kept at room temperature. the activation of additional hydration of residual cement in concrete happens at elevated temperatures, it happens to a lesser degree when there are rapid cooling regimes like water spraying. at high temperatures, the color of the concrete changes to red/pink for the concrete containing most types of siliceous aggregates. however, the discoloration may not happen with all types of aggregates al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 178 and concrete with aggregates containing ferrous salts is more likely to develop a pink hue color. the color of the concrete remains normal up to 300 o c, and then it changes to pink. when the temperature in the concrete is above 600 o c it becomes whitish grey. [soutsos, 2010]. it is considered that if the concrete’s temperature is not more than 300 o c, the residual strength after cooling is not considerably changed. when the concrete’s temperature exceeds 300 o c, it is assumed that concrete losses of strength are significant. [arpacıoglu, u., tanacan, l. & ersoy, h.y, 2008] lightweight concrete containing periwinkle shells is only suitable for structures that will be subjected to temperature less than 300 o c. [f. falade, e. e. ikponmwosa, n. i. ojediran, 2010]. lightweight concrete with vermiculite shows a good performance at elevated temperatures. expanded vermiculite is a significant lightweight aggregate for cementitious materials which are used for fire resistance applications.[f. koksal1, o. gencel, w. brostow and h. e. hagg lobland, 2012]. 2. experimental method 2.1 materials ordinary portland cement (tassluga trade mark) was used; it’s conformed to iraqi specification [iqs 5-1984] type ii [astm c150-05]. the physical properties and chemical analysis are shown in table 1. testing of cement was conducted in the laboratories of the consultant engineering bureau in babylon university. coarse aggregate was crushed clay brick (waste of local brick manufactory as lightweight course aggregate) with a maximum size of 20mm, physical and chemical properties are listed in table 2. it was separated by sieve analysis and recombined it to satisfying the grading according to iraqi specification [iqs 45-1984]. the crushed brick as lightweight coarse aggregate are shown in figure 1. rounded normal coarse aggregate from alnibaee quarry is used. the coarse aggregate was washed, and then stored in air to dry. table 2 shows the physical and chemical properties. fine aggregate was natural sand from al-akaidur region. the specific gravity and absorption values and other properties are listed in table 3.the grading is conformed to the iraqi specification [iqs 451984]. the super plasticizer used was a sulphonated naphthalene formaldehyde condensate. the aqueous solution contained 44% solids and had a density of 1210 kg/m 3 . the chloride content was negligible. it is conformed to [astm c494-05]. 2.2. mix proportions three main groups of concrete mixes were cast containing normal coarse aggregate and lightweight aggregate as coarse aggregate (crushed clay brick). the replacement of normal coarse aggregate with crushed clay brick in concrete mixes a, b and c was done correspondingly at 0%, 50% and 100% by volume, that mean the mix a was the control group. the cement content and the slump value were kept constant. table 3 shows the mix design [le larrard 1999] for three different concrete mixes containing normal coarse aggregate and light weight aggregate as coarse aggregate (crushed clay brick). the strength of the mixes was designed to be approximately 40 n/mm 2 for the control mix with slump values between 50 and 100 mm. the amount of water was adjusted to test fresh properties of concrete and get the required slump value. the air dried lightweight aggregate (crushed clay brick) was flooded with water, 24h prior to mixing, then this was drained just before mixing. sufficient water was added to the fine aggregate, 24h prior to al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 179 mixing, to satisfy the absorption. the mixing water, added subsequently was adjusted according to water absorbed by the fine aggregates. the total mixing time was 10min. 2.3. casting and curing of test specimens from each batch, specimens for specific tests were cast; the following test specimens were prepared. cubs, 150x150x150 mm in size prisms, 100 x 100 x 500 mm in size the moulded specimens were covered by thick wet polyethylene sheets to maintain a relative humidity of not less than 90%. 24 hours after casting specimens were demoulded carefully in a manner to avoid causing any spalling in the specimens, and placed it in a curing tank filled with water until the age of test namely 28 days. 2.4. concrete testing the following tests were carried out; compressive, flexural. testing was done in accordance with the appropriate astm standard. compressive strength was carried out according to [astm c 39-03] by using a hydraulic compression machine of 2000 kn. all specimens (cub 150x150x150mm) were cured in water until testing ages 28 days. each result of compressive strength obtained is the average of three specimens. concrete prisms of dimension (100x100x500mm) were tested to determine the flexural strength at 28 days. [astm 78-03] 2.5 heating and cooling down process the total amount of cubes and prisms used for testing was 54 and 36 respectively. specimens were exposed to temperature levels of 20 o c, 100 o c, 200 o c, 300 o c, 400 o c and 500 o c. for each set of temperatures, 3 cubes (150x150x150) mm and 2 prisms (100x100x500) mm were used to determine the residual compression and flexural strength. the period of the heating was for 5 hours at each temperature increase to allow the concrete inside the samples to reach the required temperature. the dimensions of the oven used for heating were 380x350x800mm with a maximum heating capacity of 600°c. taking into consideration the size and amount of concrete specimens, it was decided to place specimens of each concrete mix in three sets to reach the specified temperature. specimens were weighed before and after heating to calculate moisture loss. after heating, specimens were left to cool down under natural conditions. 3. discussion of test results 3.1 slump the concrete mixtures had been proportioned to have a minimum slump of 100mm and unit weight not exceeding 2000kg/m 3 .the slump value was recorded as 90 mm for the control mix a, 70 mm for mix b and 60 mm for mix c. data of slump for concrete mixtures are given in table 3 3.2 compressive strength compressive strength results at age of (28 days) of concrete mixtures under increment of heating temperature are shown in table 4. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 180 figure 2. show a decrease in compressive strength with an increasing in heating temperature for all groups of concrete mixtures.concrete mixes a and b showed similar approximately compressive strength reduction after heating up to 500°c of about 75% of their initial strength. significantly lesser loss of compressive strength was observed for mix c, in which was a loss of 52%. the change of the compressive strength is given on figure 3. 3.3 flexural strength flexural strength results at age of (28 days) of concrete mixtures under increment of heating temperature are shown in table 5. figure 4. show a decrease in flexural strength with an increasing in heating temperature for all groups of concrete mixtures. the largest flexural strength reduction experienced was for mix a, which had a flexural strength of 4.3 n/mm 2 a 93% loss of initial concrete flexural strength. concrete mix b had strength of about 3.6 n/mm 2 corresponding to 83% loss. mix c containing 100% light weight aggregate as coarse aggregate (crushed clay brick) showed the least flexural strength loss of about 48% of initial strength. the flexural strength change between unheated and heated to 500°c is given in figure 5. 3.4 residual strength against temperature increments concrete mixes containing normal aggregates and light weight aggregate (crushed clay brick) confirmed similar trends of a decrease in strength with an increase in temperature. a gradual decrease of strength was observed up to 300 o c; at higher temperatures concrete specimens practiced a more severe and progressive decrease in strength. for concrete mixes containing normal aggregates the loss of compressive strength was between 20% and 35% when specimens were heated up to 300 o c. it was observed that a considerable loss of compressive strength happens when specimens are heated to the temperature higher than 300 o c. for concrete mixes a and b loss in compressive strength was 80% when samples were subjected to a temperature of 500 o c which indicates that the major loss of strength (about 45%) happens between 300 and 500 o c. when specimens of mix c were exposed to high temperature, the reduction of compressive strength happened gradually compared to other concrete mixes. the more impressive reduction of compressive strength which is observed for mixes a and b is not familiar for mix c. a similar gradual decrease of the strength is observed for all 3 mixes from the results of flexural strength. the graph for flexural strength to temperatures for each of the mixes is close to linear as shown in (fig.4). specimens of concrete mix a had a flexural strength of about 0.3 n/mm 2 when they reached 500 o c, which means they lost more than 90% of their initial strength. mix c containing light weight aggregate (crushed clay brick) had a value of 1.6 n/mm 2 with a 48% reduction of the initial flexural strength. as expected, the lightweight concrete had a better performance in high temperature loading than the concrete with normal aggregates. 3.5 color change a change in color with temperature was an indication of physical and chemical changes of aggregates used for concrete mixes. the samples heated to 200°c maintained their original color, while specimens heated to 500°c changed to pink. at this level of heating, the samples with light weight aggregate (crushed clay brick) aggregate obtained a rather more concentrated coloring than the specimens with normal aggregates. the change of the color is related with chemical transformations of the aggregates at elevated temperatures. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 181 3.6 cracking and spalling when specimens are exposed to high temperatures, they experience moisture loss due to increased pore pressure from evaporating water inside the concrete. this process results in an increase in internal stresses and therefore appearance of cracks. during the experiments, visible micro cracks on specimens appeared when temperatures of exposure were 400 o c and 500 o c. as the increase in moisture loss results in appearance of more excessive cracking, cubes heated to 500 o c had a significant increase in number and size of cracks, compared to cubes exposed to 400 o c. when specimens are exposed to high temperatures, and due to the difference in modulus of thermal expanding of cement past with normal aggregate that lead to increase in internal stresses and therefore appearance of significant cracks as shown in mix a. while in mix c that containing light weight aggregate (crushed clay brick), they observed a visible micro cracks on specimens due to the modulus of thermal expanding of light weight aggregate (crushed clay brick) was lesser than normal aggregate. 4. conclusions 1. the chemical composition, physical structure and water content of concrete were changed when exposed to high temperatures. these changes occur both in the hardened cement paste and in aggregates. it results in reduction of residual strength. 2. all types of concrete mixes containing natural aggregates and lightweight aggregates (crushed clay brick) confirmed reduction of their compressive and flexural strengths. 3. for specimens tested at temperatures between 20°c and 300°c, the reduction of the compressive strength was relatively small. however, when samples were exposed to temperatures higher than 300°c, a severe decrease in residual strength was measured. 4. adding of 50% lightweight aggregates (crushed clay brick) did not improve the residual strength of the samples heated at 500˚c significantly in comparison with samples from normal aggregates. 5. for both mixes a and b and after heating to 500°c the reduction of the flexural strength was more significant than the reduction of the compressive strength (fig.6). for samples from mix c (100% lightweight aggregates (crushed clay brick)) the reduction in compressive and flexural strength was approximately the same. 6. in conclusion, investigations that were carried out showed that concrete with lightweight aggregates (crushed clay brick) had much better performance at higher temperatures than other concrete aggregates. referneses [1] a ferhat bingol & rustem gul,(compressive strength of light weight aggregate concrete exposed to high temperatures), indian journal of engineering and materials science, vol. 11, february 2004, pp.68-72. [2] a. m. neville, 2000, (properties of concrete), fourth and final edition , england. [3] ahmet b. kizilkanat, nabi yuzer, nihat kabay, (thermo-physical properties of concrete exposed to high temperature), construction and building materials45, 2013, 157-161. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 182 [4] american society for testing and materials, 2003, c33-03 (specification of concrete aggregate, annual book of astm standard , vol.04.01.2003. [5] american society for testing and materials, 2005, c150-05 (specification of portland cement), [6] annual book of astm standard , vol.04.02.2005. [7]american society for testing and materials, 2005, c494-05 (specification of for chemical admixtures for concrete), annual book of astm standard , vol.04.01.2005. [8] american society for testing and materials,2003, c 78,( standard test for flexural strength of concrete using simple beam with third-point loading), annual book of astm standard,2003 [9] american society for testing and materials,2003, c-39,( standard test for compressive strength of concrete), annual book of astm standard,2003 [10] arpacıoglu, u., tanacan, l. & ersoy, h.y.(effect of high temperature and cooling conditions on aerated concrete properties.) construction and building materials. (2008) [11] bazant, z.p., kaplan, m.f. )concrete at high temperatures. material properties and mathematical models(. har-low: longman group limited, (1996). [12] f. falade, e. e. ikponmwosa, n. i. ojediran (behavior of lightweight concrete containing periwinkle shells at elevated temperature), department of civil and environmental engineering, university of lagos, lagos, nigeria, journal of engineering science and technology, vol. 5, no. 4 (2010) 379 – 390 school of engineering, taylor’s university [13] f. koksal1, o. gencel, w. brostow and h. e. hagg lobland (effect of high temperature on mechanical and physical properties of lightweight cement based refractory including expanded vermiculite), materials research innovations 2012 vol 16 no 1 [14] h.m.albaghdadi,( using local materials wastes for development of high strength lightweight concrete), babylon journal , vol. (2010). [15] harmathy, t.z. and allen, l.w. thermal properties of selected masonry unit concretes. journal american con-crete institution 70(2) , (1973) [16] iraqi organization of standard, iqs 45-1984 , for natural aggregate resources . [17] iraqi organization of standard, iqs 5-1984 , for portland cement . [18] le larrard, f, (concrete mixture proportioning) , a scientific approach, london, 1999. [19] peng, g.f., bian, s.b., guo, z.q., zhao, j., peng, x.l. and jiang, y.c. ( effect of thermal shock due to rapid cooling on residual mechanical properties of fiber concrete exposed to high temperature). (2006) al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 183 [20] soutsos, m. (concrete durability. a practical guide to the design of durable concrete structures). london: thomas telford limited. (2010) [21] wdison, c. (concrete ship resists sea water thirty four years), concrete. vol. 62, no.1, 1954, pp 5-8. table 1: chemical compositions and physical properties of (type ii) ordinary portland cement (tassluga). compound composition chemical composition percentage by weight limits of ios 5:1984 lime cao 62.41 silica sio2 21.78 alumina al2o3 4.85 iron oxide fe2o3 3.96 magnesia mgo 1.98 <5 sulfate so3 2.55 <2.8 loss on ignition l.o.i 3.11 <4 insoluble residue i.r 1.28 <1.5 lime saturation factor l.s.f 0.95 0.66-1.02 physical properties test result limits of ios5:1984 fineness using blain air permeability apparatus (m 2 /kg) 315 >230 soundness using autoclave method 0.19% <0.8% setting time using vicat’s instruments initial (hrs: min) final (hrs: min) 2: 50 4 : 44  0:45  10:00 compressive strength for cement mortar 3 days (mpa) 7 days (mpa) 22.3 31.5 >15 >23 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 184 table 2: physical properties of lightweight (crushed brick) and normal coarse aggregate. properties test results lightweight test results normal limits of iraqi specification no.45/1984 specific gravity 1.65 2.66 absorption 25.4% bulk density 1105 kg/m 3 1660 kg/m 3 percentage passing sieve size 75 micron 0.60% 0.1% max. 3% gradation of gravel for maximum size 20mm sieve size(mm) passing % lightweight passing % normal limits of iraqi specification no. 45/1984 75mm 100 100 37.5mm 100 100 100 20mm 95 97 95-100 14mm 10mm 36 42 30-60 5mm 4 6 0-10 table 3: physical properties of fine aggregate from al-akaidur region properties test results limits of iraqi specification no.45/1984 specific gravity 2.56 absorption 11% moisture content 0.15% so3 0.21% max. 0.5% percentage passing sieve size 75 micron 0.32% max. 5% gradation of gravel for maximum size 20mm sieve size(mm) passing % limits of iraqi (zone 2) specification no. 45/1984 9.5 mm 100 100 4.75 mm 98 100-90 2.36 mm 85 100-75 1.18 mm 70 90-55 0.6 mm 50 59-35 0.3 mm 18 30-8 0.15 mm 3 10-0 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 185 table 4: concrete mix design [le larrard 1999] mix a control mix mix b mix c cement (kg) 64.3 64.3 64.3 water letter 29.20 21.2 24.7 sand (kg) 75.5 75.5 75.5 normal coarse aggregate (kg) 160.4 80.2 0 light weight aggregate (crushed clay brick) kg 0 30.8 61.6 slump mm 90 70 60 table 5:. compressive strength results table 6: flexural strength results temperature mix a mix b mix c compressive strength mpa 20oc 40.4 37.0 26.7 100oc 37.6 34.4 23.1 200oc 35.4 30.8 20.1 300oc 31.3 23.3 18.8 400oc 25.4 15.6 13.8 500oc 10.0 8.6 12.7 temperature mix a mix b mix c flexural strength mpa 20 o c 4.3 3.6 3.1 100 o c 3.7 3.2 2.5 200 o c 2.9 2.6 2.2 300 o c 1.8 1.8 2.1 400 o c 1.2 1.0 1.8 500 o c 0.3 0.6 1.6 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 186 figure (1): crushed brick as lightweight coarse aggregate figure (2): relation of compressive strength with increment temperature 0 5 10 15 20 25 30 35 40 45 0 100 200 300 400 500 600 c o m p re ss iv e s tr e n g th m p a temperature ˚c mix a mix b mix c al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 187 figure (3): change of the compressive strength. figure (4): relation of flexural strength with increment temperature 0 5 10 15 20 25 30 35 40 45 mix a mix b mix c c o m p re ss iv e s tr e n g th m p a 20 c 500 c 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 100 200 300 400 500 600 f le xu ra l s tr e n g th m p a temperature ˚c mix a mix b mix c al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 188 figure (5): change of the flexural strength. figure (6): reduction in strength of concrete mixes after heating to 500°c 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 mix a mix b mix c f le xu ra l s tr e n g th m p a 20 c 500 c 0 10 20 30 40 50 60 70 80 90 100 mix a mix b mix c r e d u ct io n o f s tr e n g th % comp.str. flexu.str. microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 66 analytical model to determine probability density function of amorphous silicon with dangling bonds and correlation effect among them mazin m. ali msc. electronic engineering al-qadisiya university – college of engineering abstract: the probability density function of a-si, taking into consideration presence of dangling bonds with correlation effect, is derived . the effects of temperature, trap level positions, free carriers concentrations and ratio of capture cross sections on the probability density function have been studied with respect to various positions of donor like and acceptor like trap levels, where it is found by matlab that variation of position of acceptor like trap level divides the curve of probability within air gap into three sublevels of values one, zero and the third has values in between. these sublevels have been affected by increasing the temperature of a-si wafer, changing the concentration of free carriers and position of donor like trap level, while changing of ratio of capture cross section has no effect on the distribution of probability density function. نموذج تحليلي لتحديد دالة آثافة االحتمالية للسليكون العشوائي بوجود األواصر المتدلية والتأثير المتبادل بينها مازن مكي علي ماجستير هندسة الكترونية / آلية الهندسة–جامعة القادسية الخالصة ق معادلة دالة آثافة االحتمالية للسليكون العشوائي أخذين بنظر االعتبار وجود األواصر المتدلية و التأثير المتبادل فيما بينها تم اشتقا ثم تم دراسة تأثير آل من درجة الحرارة و موقع مستوى الصيد وقيم مختلفة لترآيز حامالت الشحنة الحرة و نسبة المقطع الجانبي . وبمساعدة البرنامج .بالواهبة لمواقع مختلفة لمستويات الصيد الشبيهة بالمتقبلة والشبيهة " ثافة االحتمالية نسبتا للصيد على دالة آ matlab ، فقد تبين أن تغيير موقع مستوي الصيد الشبيه بالمتقبل أدى لتقسيم منحني دالة آثافة االحتمالية إلى ثالثة مستويات ؤ وهو ذات قيمة تساوي واحد ، والثاني قريب من حافة حزمة التوصيل وهو ذات قيمة تساوي األول قريب من حافة حزمة التكاف هذه المستويات تأثرت بازدياد درجة الحرارة و تغير ترآيز . صفر ، أما الثالث فيقع بينهما ويمتلك قيم تتغير بين الواحد والصفر متقبل ، بينما لم يظهر أي تأثير لتغير نسبة القطع الجانبي للصيد على حامالت الشحنة الحرة وتغير موقع مستوي الصيد الشبيه بال . منحني الدالة al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 67 introduction: the structure of amorphous silicon, a-si, characterizes by presence of high density of states in the gap between conduction and valance bands. those states act as traps or generation recombination centers. so the concentrations of captured carriers in a-si is much greater than concentrations of free carriers [madan ,1976]. therefore, in contrast with single crystalline silicon, the conduction band and valance band in a-si are not separated by clearly defined energy gap, where the acceptor like and donor like states are tailing in that gap and overlapping approximately in the middle of gap [madan ,1976]. many experiments had been achieved to determine style of proper distribution of that states within the gap. the model of most compatible experimental results with practical events was the distribution model suggested by hack, guha and shur , where the density of acceptor like states ga(e) and donor like states gd(e) are described by the given functions [hack,1985 ] : cccta weeaeg /)exp(.)( −= … ( 1 ) vvvtd weeaeg /)exp(.)( −= … ( 2 ) where act and avt are the concentration of acceptor like and donor like states at the edges of conduction and valance bands respectively . the electrical properties of a-si and its electronic structure are greatly affected by the distribution of those states and their cases, if they were empty or occupied by carriers [balberg,2001]. the occupation of states is governed by fermi – dirac distribution [madan ,1976]. out of thermal equilibrium, occupation of states is strongly related to the dynamic of thermal generation – recombination rate of charge carriers [furlan,1987]. mathematically , the occupation of acceptor and donor like states in undoped a-si are described by the following equations, called the occupancy density functions related to acceptor and donor like states , fta and ftd , respectively [furlan,1987] : 11 1 )( nnppr npr f a a ta +++ + = … ( 3 ) 11 1 )( ppnnr pnr f d d td +++ + = … ( 4 ) where n , p are the concentration of free carriers, p1 and, n1 are concentration of captured carriers with respect to a certain g – r center related to the intrinsic fermi level. in amorphous semiconductors, defects are of different kinds as compared to crystalline materials, the main defects are those related to the deviations from the average coordination number, bond length and bond angle, which will cause disorder in stracture of amorphous silicon [yacobi, 2004]. due to this disorder, the concentration of dangling bonds normally rises, those dangling bonds occur when silicon atom does not bond to four neighboring atoms [6] . the presence of dangling bonds widely affects the distribution of states densities in a-si and badly affects the properties of amorphous silicon [fritzsche,1977] . to study effect of dangling bonds , they are represented by different mathematical formulas . the representation adopted by alsamrai is also adopted here, where the bonds are given by peaks of fixed amplitude , aa and ap , and fixed width ∆e [al – samarai,1989 ]. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 68 many studies have been achieved to overcome the problems related to defects produced due to presence of dangling bonds in structure of a-si, the most important method in this field that suggests doping the a-si with some concentration of hydrogen to produce the hydrogenated amorphous silicon a-si:h [feldmam,2004], and the more recent method is that depending on germanium induced perimeter to get crystallized a-si [hakim ,2007]. theory in the energy gap, there are the density of positive ions which are equal to density of empty donor like states gtd – gtd, the density of negative ions which are equal to density of occupied acceptor like states gta, and the neutral atoms which are equal to density of empty acceptor like states gta – gta, where gtd and gta represents the total concentrations of donor like and acceptor like states, empty plus occupied, in presence of dangling bonds with correlation effect among them . so the overall concentrations of states is given by : )()( tatatatdtdt gggggg −++−= … ( 5 ) which can be rewritten as : tdtdtat gggg −+= … ( 6 ) the probability density function of acceptor like states in presence of dangling bonds and correlation effect , fta , represents the ratio of concentration of occupied acceptor like states , gta , to the total concentration of states gt ,[ montgomery,2003] : t ta ta g g f = … ( 7 ) which can be found equal to : aa aa dd dd aa aa ta prn prn nrp nrp prn prn f 1 1 1 1 1 11 1 + + ⋅ + + + + + + = … ( 8 ) while the probability density function of donor like states in presence of dangling bonds and correlation effect , ftd , represents the ratio of concentration of occupied donor like states , gtd , to total concentration gt ,[ montgomery,2003] : t td td g g f = … ( 9 ) which can be found equal to : prn prn nrp nrp f aa aa dd dd td + + + + + + = 1 1 1 11 1 … ( 10 ) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 69 where n1a , p1a are the concentrations of captured carriers with respect to acceptor like trap level , n1d , p1d are the concentrations of captured carriers with respect to donor like trap level and ra , rd are the capture cross section ratios with respect to acceptor like and donor like states respectively . the results : the probability density functions of amorphous silicon , a-si , with dangling bonds and correlation effect among them, is studied through four obtained curves for fta using matlab, the first curve is for variation of probability density function of a-si , fta , with position of acceptor like trap level eta for different values of free carriers concentrations n and p at certain donor like trap level, the second is for variation of fta with position of acceptor like trap level eta for various positions of donor like trap levels at certain concentration of free carriers, the third is for variation of fta with acceptor like trap level eta for different values of temperature and the fourth is for variation of fta with position of acceptor like trap level eta for different values of captured cross section ratios ra and rd .the calculations were performed regarding the value of intrinsic concentration ni = 1.9 x 105 cm-3 , ratios of capture cross section ra = rd =100 , temperature t = 25 c0 and position of fermi level ei = 0.8 ev. figures ( 1 ) through ( 4 ) show the results of those studies, where: 1. figure(1) , shows that variation of probability density function fta through the gap , between conduction and valance bands , with position of acceptor like trap level, eta , and the donor like trap level is at position etd=0.4ev, it is found that the probability density function can be divided into three sub regions , the first is that close to valance band where value of fta is very close or equal to one , the second is that close to position of intrinsic fermi level ( ei ) where the values of fta sharply drop to zero to form the third region which close to conduction band . 2. if the curves of figure(1) are compared with similar curves obtained by furlan [4] for a-si without dangling bonds , it shows that presence of dangling bonds , with correlation effect , makes the second region very narrow , that beyond to presence of dangling bonds and correlation effect where that effect will lead to increase the density of defects. this explains the reason of bad effect of correlation effect among dangling bonds on photoconductivity of a-si where taylor and simmon [1972] had been mentioned that the majority of generation recombination rate has been taken place in this region . 3. figure(1) shows, too ,that the first and third regions widths vary with variation of free carriers concentrations , n and p , where more concentrations of free carriers mean less concentrations of captured carriers and vise verse , which also means less or more occupation of captured levels effecting values of fta and ftd . 4. figure(2) shows variation of probability density function fta with position of acceptor like trap level eta for three positions of donor like trap levels etd 0.2ev, 0.6ev and 1.0ev . by this figure, it is clear that the donor like trap level at position 1.0ev, has no effect on probability density function ( fta ) because this position of etd is above fermi level ( ei = o.8ev approximately ) where the normal and effective position to etd is below ei , while for values of etd less than ei, gives us a hint that decreasing of etd leads to corresponding decrease in the region of fta equal to one, where less value for position of donor like trap level etd means that the donor like trap level is much closer to valance band making it in higher activity to trap the electrons and holes of that band . al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 70 5. figure(3) , shows variation of probability density function fta with the position of acceptor like trap level eta for three different values of temperature , t . it is found that increasing the temperature of a-si wafer improves its properties by making the structure of wafer approaches to crystallization [mullin,2001]. so, as temperature increases in figure(3), the second sublevel becomes wider, which is an essential region in the gap of amorphous silicon because the majority of generation recombination process has been taken place in this region . 6. by figure(4), effect of changing the ratios of captured cross section , ra and rd on probability density function fta, is studied , where fta via eta was plotted for three different values of ra and rd and it was expected to get three different curves for fta but it is found only one, which means that varying the value of ra or rd has no effect on fta . that beyond to increasing of defects due to the bad effect of dangling bonds and correlation effect among them, which will lead to cancel the second region , where the effect of changing ra or rd on fta is expected to be noticed . this result has been enhanced mathematically by partial derivative of fta with respect to capture cross section ratio ra ( ata rf ∂∂ / ) which found equal to zero . similar result was deduced by furlan [1987] when he studied the probability density function in undoped amorphous silicon, without dangling bonds, where he mentioned that "changing in captured cross sections ratios ra or rd will only affect the width of second region". here, as the width of second region, is drastically eliminated , nearly to zero, so it is acceptable to say that ra or rd has no effect on probability density function . conclusions: 1. increasing the doping of a-si wafer will shift the curve of probability function toward conduction band, causing in making the region of fta =1 wider, this beyond to the fact that doping can control the position of fermi level . 2. as the position of donor like trap level etd moves to be closer to conduction band, the curve of probability density function shifts toward the valance band where the empty acceptor like trap states increases . 3. rising the temperature of amorphous silicon wafer will effect the width of middle region making it wider and decreasing the width of first and third regions. 4. changing the ratio of capture cross section has no effect on the probability density function of amorphous silicon. 5. in general, presence of dangling bonds with correlation effect among them will badly affect the properties of amorphous silicon by affecting the width of middle region of probability density function which play an important rule in determining the properties of a-si because most of generation recombination process has taken place in this region. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 71 references: 1) a. madan , p.g. lecomber , w.e. spear , investigation of the density of localized states in a-si , journal of non-crystalline solids20 , 1976 . 2) m.hack , s.guha , m.shur , photoconductivity and recombination in amorphous silicon alloys , j. applied physic , vol. 30 , no.12 , 1985 . 3) i. balberg , transport and phototransport in amorphous and nanostructured semiconductors , journal of optoelectronics and advance materials , vol.3 , no.3 , p587-600 , 2001. 4) furlan , s. amon , f. smole , occupation probability distribution , melc.87 , rome – italy , march24-26 , 647 , 1987. 5) b. g. yacobi , semiconductor materials an introduction to basic principles , new york , kluwer academic puplishers , 2004. 6) amorphous silicon , from wikipedia , the free encyclopedia , internet , “http://www.wikipedia.org/wiki/amorphpus_silicon” 7) h. fritzsche , the nature of localized states and effect of doping in amorphous semiconductors , chinese journal of physics , vol. 15 , no.2 , 1977. 8) j. al – samarai , analytical model to determine the photoconductivity of hydrogenated amorphous silicon , phd dissertation , ljubljana , yugoslavia , 1989 . 9) j. l. feldmam , tight-binding study of structure and vibrations of a-si , j. phy.rev. , b70 , 165201 , 2004. 10) m.m.hakim and p.ashbur , mechanism of germanium – induced perimeter crystallization of a-si , journal of electrochemical society , 154 (4) ,h275-h282 , united kingdom , 2007. 11) douglas c. montgomery , applied statics and probability for engineers , john wiley and sons , 2003. 12) w. taylor and j. simmon , basic equations for statics, recombination processes, and photoconductivity in amorphous insulators and semiconductors , j. noncrystalline solids , 8-10 , 940 (1972) 13) j. w. mullin , crystallization , reed educational and professional publishing ltd , fourth edition , 2001. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 72 al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 73 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 01 دراسة مقارنة للخواص الفيزيائية بين الطابوق العراقي واإليراني المثقب عبد الهادي متعب حسن محمد كريم عبد ضياء نعمة جبار (.dhiaanj@yahoo.com ) قني / بابلالمعهد الت المستخلص .هذا البحث دراسة مقارنه للخواص الفيزيائية بين الطابوق الطيني المثقب العراقي و االيراني يقدم اختيارها بشكل عشوائي من االنتاج المتوفر في ( عينه من الطابوق الطيني المثقب تم 300) تم كل معمل (.لطابوقة 30االسواق المحلية لخمسة معامل عراقية وخمسة معامل ايرانية ) لعام 24اختيار النماذج وفحصها وفق الطرق القياسية وطبقا للمواصفة القياسية العراقية رقم لعام 25المواصفة القياسية العراقية رقم متطلبات م نتائج االختبارات وفقيوتم تقي 1988 هي :المظهر العام الخواص الفيزيائية التي تم اختبارها وطبقا للمواصفة القياسية العراقية .1988 والتفاوتات باإلبعاد عن االبعاد القياسية والتحدب والتقعر و االمتصاص ومقاومة االنضغاط كان افضل من الطابوق االيراني في تفاوتات اظهرت النتائج بان الطابوق العراقي والتزهر. االبعاد وفي االمتصاص بينما كان الطابوق االيراني افضل من الطابوق العراقي من ناحية وعند تقيم كافة المظهر العام والتحدب والتقعر ومقاومة االنضغاط باإلضافة الى التزهر. العام فقد بينت مية لغرض التقييلمواصفة العراقلالخواص المفحوصة وفق المتطلبات العامة النتائج بان الطابوق العراقي كان افضل من الطابوق االيراني وان كافة النماذج المفحوصة يمكن أ .يوجد اي نموذج ضمن الصنف ال و جاو ب ان تصنف ضمن الصنف الكلمات الدالة الطابوق االيراني. ،يالطابوق العراق ،الطابوق الطيني المثقب ،الطابوق، الطابوق الطيني mailto:.dhiaanj@yahoo.com 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 00 a comparison study for physical properties between iraqi and iranian perforated bricks d. n. jabbar m. k. abed dr. a. h, m. hassan lecturer lecturer assist prof. babylon technical institute abstract this research presents a comparison study for physical properties between iraqi and iranian perforated clay bricks. 300 samples of perforated clay bricks are randomly selected from the production of five iraqi factories and five iranian factories which are available in local markets ( 30 bricks from each factory ). all samples are selected and tested by standard methods according to iraqi standard specification no. 24/1988. the results of the tests are evaluated according to the requirements of the iraqi standard specification no. 25/1988. the physical properties that have been tasted (according to the requirements of iraqi specifications) are; general appearance, deviation of dimensions from standards, concave and convex, absorption, compressive strength and efflorescence. the results show that iraqi bricks are better than iranian bricks in deviation of dimensions from standards and absorption while iranian bricks are better than iraqi bricks in general appearance, concave and convex, compressive strength and efflorescence. when all tasted properties are evaluated with general requirements of iraqi specifications for general evaluation, results show that iraqi bricks are better than iranian bricks and all samples of bricks can be classified within either class b or c and no unite within class a. المقدمة: 1ان الطابوق الطيني ال زال إالعلى الرغم من تعدد وتنوع المواد البنائية المستخدمة في االنشاء يشكل مادة اساسية في اعمال البناء في كثير من الدول ومنها العراق وخاصة في وسط وجنوب بليون قبل سبعة فالطابوق يعتبر من مواد البناء المصنعة المهمة وقد عرفه واستعمله البا .العراق آالف سنة والزال شائعا حتى اآلن حيث تطورت طرق تصنيعه وتعددت انواعه من حيث الشكل واللون والمتانة لتحقيق اهداف معمارية او هيكلية معينة ولمختلف اصناف ومراحل التشييد ابتداء خن المعامل والقناطر والسدود ومدا واألسوارالسكنية والمعابد ر من االساس حتى اكمال الدو . (6002)سرسم وعبد العال، والسقوف وغيره واألرصفةوالجدران الساندة التااي تسااتعمل فااي البناااء والتااي ال تزيااد واإلبعااادالوحاادات البنائيااة المنتظمااة الشااكل هااوطااابوق ال أن المواصافة البريطانياة .عن ذلا فتسامى كتلاة بنائياة هاابعادها عن حد معين وعندما تزيد ابعاد وملام طاوال 337.5عرفت الطابوق بأنه الوحادة البنائياة التاي ال تتجااوز 3921/1974قمة المر ملم سمكا والكتلة البنائية هي الوحدة البنائية التي تتجاوز في الطول 112.5ملم عرضا و 225 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 03 فااي حااين . (1991ليفههون، سههاكو و ; 1991)السهههيري، المااذكورةالعاارض او الساام األبعاااد او ملاااام 65×102.5×215 المقترحااااة للطااااابوق ماااان قباااال اتحاااااد تطااااوير الطااااابوق هاااايان االبعاااااد (barry,1978) .حسب المواصفاتو ألخرمقاسات الطابوق تختلف من بلد كل عام فانشوب ذيالااالطااابوق وأشااكالهااذه المقاسااات تختلااف ايضااا عاان مقاسااات كمااا ان السااائدة فااي ذلاا البلااد ق المستعمل حاليا في العراق هو اصغر من الطابوق الاذي . فالطابو سابقةالعصور الستعمل في ا ان ابعااااد الطاااابوق كاااان يساااتخدم فاااي العصااار العباساااي او فاااي زمااان الباااابليين. ومماااا الشااا فياااه فااا سههههههاكو و ) واإلنتاااااااجالحاليااااااة تسااااااتند علااااااى اسااااااس متطلبااااااات التصااااااميم وسااااااهولة البناااااااء والنقاااااال لنااورة )اوكساايد الكالساايوم( والرماال او الطااابوق عبااارة عاان قطااي ماان الطااين او اف (.1991ليفههون، الخرساااانة او اي ماااادة مناسااابة اخااارق تعمااال بشاااكل قطاااي منتظماااة االبعااااد يمكااان صااانعها ونقلهاااا واسااتعمالها بسااهولة فااي البناااء ولهااا القابليااة لتحماال االثقااال ومقاومااة التااأثيرات والتغياارات الجويااة. لة في صنعه كالطابوق الطيني والرملاي و يصنف الطابوق تبعا لعدة عوامل منها:المواد المستعمو الخرساني او طريقة صنعه كالطابوق الميكانيكي ونصف الميكانيكي واليدوي او لنوعية الطابوق لمقااادار بالنسااابةاو واألبااايض واألصااافربالنسااابة للحااارارة المعطااااة للطاااابوق كالطاااابوق المصاااخرج الثقااال فااي الجاادران والثاااني وهااو تحملااه حيااث يصاانف الااى صاانفين االول وهااو المسااتعمل لنقاال ا . (1996)الدواف، المستعمل لحجز فراغات في االبنية الهيكلية ان اكثر انواع الطابوق استعمااًل ) في العراق ( هو الطابوق الطيني وذل لعدة عوامل اهمها ة ومقاومته وتحمله للقوق وعزله للحرار انتاجه القليلةمادة الخام في كل مكان تقريبا وكلفة التوفر لقد . (1996)الدواف، كما ان لبقية انواع الطابوق خواصها المميزة ايضاً ,للنار والتغيرات الجوية بشكل طين في االبنية البدائية ثم بشكل طين مقطوع مادة الطابوق االولية استعملت ةوقد استعمل االنسان هذه الماد .)طابوق(كل مقطوع ومجفف ومفخورشومجفف)لبن( ثم ب التي ال يضاهيها اي مادة بنائية من وادزاتها العديدة و يعتبر الطابوق لحد االن من الملمي ان تسمية ) الطابوق ( يقصد .(1996)الدواف، حيث الكلفة مي القوة ومقاومة التغيرات الجوية وهذا يدل على ان هذا .(barry, 1978)في الغالب الطابوق الطيني المفخور االعتيادي بها من نوع واحد بأكثروالذي ينتج ,(1991)ساكو و ليفون،اهو االكثر استعماال وشيوعالنوع ذل النوع من بأنهمنها المصمت والمثقب والمجوف والخلوي وغيرها ويعرف الطابوق المثقب % من حجمه ويستعمل في االبنية 25الطابوق الذي ال يزيد مقدار احتوائه على ثقوب على ساكو و ;6002)سرسم وعبد العال،وفي القواطي والحواجز باإلثقاليا والمنشات المحملة نسب .(1991ليفون، تعتباار صااناعة الطااابوق ماان الصااناعات االنشااائية الرئيسااية فااي العااراق ويعتباار المااادة االولااى فااي بناء الجدران في المنطقتين الوسطى والجنوبية مان العاراق حياث طبيعاة الترباة الرساوبية المسااعدة 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 02 عته وكون البدائل المنافسة غير قادرة على التعويض عن استعماله بدرجاة كبيارة وذلا على صنا الخواص الهندسية للبناء النااتج , البناءلعدة اسباب منها توفر المواد االولية, كلفة التصنيي , كلفة .علياه في محافظة بغداد وذل لكثرة الطلب يكانت صناعة الطابوق تتركز بشكل رئيس وغيرها. قطااع خااص ( فاي غالبيتهاا أال ان لقد كانت صناعة الطابوق و لسانوات طولياة صاناعة اهلياة ) عدم تمكن تلا الصاناعة مان مواكباة متطلباات التنمياة آناذا مان حياث الكمياة والنوعياة ادق الاى ان يقاااوم قطااااع الدولاااة)في الرباااي االخيااار مااان القااارن الماضاااي( بمهماااة التوجياااه والنهاااوض بتلااا الهاماااة وأنشاااأت فعاااًم عاااددًا مااان المعامااال الحديثاااة ذات الساااعة العالياااة ونوعياااة االنتااااج الصاااناعة (.1991)ساكو و ليفون، االفضل ووزعت بشكل مدروس على محافظات القطر حسب الحاجة خيااارة ومناااذ بااادايات القااارن الحاااالي ازداد الطلاااب علاااى هاااذه الماااادة بسااابب تحسااان وفاااي االوناااة اال عديادة مان الماواطنين والتوساي فاي اعماال البنااء واألعماار. وماي ازديااد المستوق المعاشي لشرائح الطلب قل انتاج هذه المادة بسبب الظروف االستثنائية التي يمر بها القطر والنقص الاذي حصال فااي اماادادات الطاقااة الكهربائيااة والوقااود ممااا ادق الااى اللجااوء الااى اسااتيراد هااذه المااادة ماان الاادول انواع عديدة مان الطاابوق االيراناي شاائعة التاداول فاي االساواق وأصبحتن. المجاورة وخاصة ايرا المحلية وبسعر قاد يكاون اقال مان اساعار الطاابوق العراقاي. وألهمياة التحاري عان بعاض الخاواص الهندسية لألنواع المستخدمة من الطابوق االيراني في االسواق المحلية ومدق مطابقتها لمتطلبات تم القياام بهاذه الدراساة . حياث تهادف هاذه الدراساة ومقارنته بالطابوق العراقي المواصفات العراقية يم مادق مطابقتاه ياالى اجراء مقارنة بين الخواص الفيزيائية للطابوق العراقي واإليراني المثقب وتق لمتطلبات المواصفة العراقية للطابوق الطيني . ق تعماال وتجمااي بااين عاادة خااواص الااى فحوصااات اخاار باإلضااافةيفحااص الطااابوق لجميااي خواصااه فااي فحااص واحااد لمعرفااة ماادق تااأثير هااذه الخااواص عليااه. ان هااذه الفحوصااات تشاامل الفحوصااات االمتصااص, مقاوماة الضاغط الكسارمعااير قاد تشامل ) ية والميكانيكياة وهايائة والفيزيئيالكيميا البدائياة االمتصااصسارعة الذائباةاألمام , المسامية, األنجماد واألنصهار تأثير التشبيعامل , تناولات العدياد ماان المصاادر طاارق اجاراء الفحوصااات علاى الطااابوق .(1996)الههدواف، التزهار, 1991،النعيمهي ;1991عبد العال وعبد الجبهار، ;1996الدواف، ;6002)سرسم وعبد العال، ,نااي موضااوع الطااابوق الطي 1988لعااام 25و 24رقاام المواصاافة القياسااية العراقيااة عالجاات .( فاستعرضات المواصاافة االولااى طريقااة النمذجااة و طاارق الفحاص القياسااية فااي حااين تطرقاات الثانيااة فقااد صاانفت هااذه المواصاافة الطااابوق الااى ثمثااة .م النماااذج وتصاانيف الطااابوقيالااى موضااوع تقياا ضحت هاذه المواصافة باان الطاابوق يمكان ان يكاون و ا وو ب و ج (. أ )فاصناال اصناف هي ان االبعاااااد القياساااية هااااي و (لمجاااوفوا المثقاااابو المصااامت ) الطااااابوقاع هاااي علاااى ثمثاااة انااااو اختبااارات تجاارق وفااق الطاارق القياسااية سااتة وبيناات المواصاافة بااان هنالاا . ملاام 75×115×240 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 07 و)التحاادب المظهاار العااام و التفاااوت فااي االبعاااد {لتقاايم النماااذج وتصاانيفها وهااذه االختبااارات هااي .(61/1999م ق ع ;62/1999)م ق ع صاص الماء والتزهروتحمل الضغط وامت والتقعر( البرنامج العملي 2 : المواد المستخدمة 1-2 و شركة القيروان معامل هي )معمل المحاويل و لخمسةلطابوق العراقي اتم اخذ عينات فحص هذه المعامل عدق معمل المحاويل تقي (لييابو رياض وشركة قاسم العك الشيحاني ومعملمعمل معامل ايضا هي )معمل لخمسةوللطابوق االيراني ضمن معامل منطقة النهروان ومعامل بغداد ( وتمت عملية فخاري نيا ومعمل ومعمل صادقيان دوستان و معمل اصفهان ومعمل قبانجي )م ق ع 1988لعام 24النمذجة وكافة الفحوصات المختبرية وفق المواصفة العراقية رقم 62/1999.) نماذج : ال 2-2 إلجراءبشكل عشوائي لكل معمل من المعامل المذكورة اعمه قة(بنائية)طابو ( وحدة30تم اخذ ) الفحوصات ألجراءالفحوصات الوردة في المواصفة المعتمدة حيث ان عدد النماذج المطلوبة عليها كما يلي: (كافة عينات الفحصطابوقة ) 03 فحص المظهر العام -1 طابوقه 24 تفاوت االبعادص فح2 طابوقة 10 فحص استواء السطح 3 قةطابو 10 فحص االمتصاص -4 طابوقه 10 فحص االنضغاط -5 طابوقه 10 فحص التزهر -6 قياس المظهر العام استخدمت في فحص التي جرق عليها فحص جزء من الوحدات علما بان وان استخدمت في فحص استواء السطح وهذه استخدمت في فحوصات اخرق منهاوجزء االبعاد فحص االمتصاص.في اجري على عينات استخدمتمثم فحص الضغط الفحوصات المختبرية 2-3 فحص المظهر العام 1-3-2 جوانب ومدق المة واستقا يااوطبيعة الزو تم معاينة الشكل العام لنماذج الفحص ومدق انتظامه الحجر واقطي الحصى على احتواء النماذج ومدق وتجانس الحرق وجودتهوجود تشقق او تثلم نسبة الطابوق السليم الخالي من العيوب. وتم حسابالعقد الجيرية وا 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 07 فحص التفاوت باألبعاد 3-2 -2 جنبا الى ( طابوقة من عينات الفحص لكل معمل وتم رصفها على سطح مستوي 24تم اخذ) جنب بصورة متمصقة و بخط مستقيم بعد ازالة النتوءات او حبيبات الرمل العالقة قبل رصف مرة على الطول وأخرق بحيث يكون عرض الطابوق جنبا الى جنب وتم الرصف الطابوق, تم قياس كم من الطول والعرض والسم لصف الطابوق .بوضي الطابوق على الكاز وأخرق طابوقة مرة واحدة باستخدام شريط فوالذي و ايجاد المتوسط الحسابي إلبعاد (24)الكلي الممثل ل ( طابوقة الذي يكون ممثم إلبعاد الطابوق المفحوص.24) التقعر و التحدب( لسطح )استواء ا فحص 3-2-3 عرفحص التق -أ ح النماذج ( طابوقات من عينات الفحص لكل معمل وتم ازالت اي نتوءات عالقة بسط10تم اخذ) فوالذية مدرجة ووضعت المسطرة طوليا مرة وقطريا مرة اخرق فوق سطو كل .تم اخذ مسطرة نموذج من النماذج المراد فحصها وتم اختيار الموضي الذي يعطي اكبر ابتعاد عن االستواء تي كبر بين حافة المسطرة وسطح الطابوقة وال)اعلى قيمة( وتم قياس هذه المسافة وهي البعد اال .سطح التمثل التقعر في فحص التحدب -ب تم اخذ عينات الفحص التي اجري عليها فحص التقعر ووضعت كل طابوقة على لو زجاجي لو وكل زاوية المستوي تماما بحيث يكون وجهها المحدب مممسا للو .تم قياس المسافة بين باره مقدار التحدب لكل طابوقة وتم عتامن زويا الطابوقة االربعة وسجل معدل القياسات االربعة ب لتمثل مقدار التحدب لكل نموذج . من هذه القيم اختيار اعلى قيمة فحص االمتصاص : 2-3-4 ( طابوقات من عينات الفحص لكل معمل و تجفيف نماذج الفحص في فرن كهربائي 10تم اخذ) ومن ين ثبوت الكتلة ( ساعة ولح36( درجة مئوية ولمدة ال تقل عن ) 115-110بدرجة حرارة ) تبريد هذه النماذج بدرجة حرارة الغرفة وبعد ذل تم قياس كتلة كل طابوقة باستخدام ميزان تم ثم من ( ساعة و 24غمر هذه النماذج بحوض فيه ماء لمدة )تم كهربائي والذي تمثل الكتلة الجافة. كتلة كل قياسوبعدها سطحها الخارجي بقطعة قماش و تجفيفرفي هذه النماذج من الماء ثم طابوقة والذي تمثل الكتلة الرطبة وتم حساب نسبة االمتصاص لكل طابوقة ومن ثم حساب معدل االمتصاص لكل نموذج . 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 07 فحص مقاومة االنضغاط: 3-2-5 تم اخذ نماذج الفحص المستخدمة في فحص االمتصاص بعد قياس كتلها الرطبة مباشرة وهي نضغاط عليها باستخدام جهاز فحص الضغط العام. تم حسابمشبعة ألجراء فحص مقاومة اال العرض( كما تم حساب عدد الثقوب لكل xسطحي التحميل لكل طابوقة )الطول مساحة طابوقة وقياس اقطارها لغرض حساب سطح التحميل واستخدام اصغرها لحساب مقاومة يث ينطبق محور العينة تم وضي الطابوقة بين لوحي جهاز الضغط الفوالذيين بح االنضغاط. على مركز اللو المرتكز على القاعدة الكروية. تم فحص الطابوقة حسب وضعها في البناء اي العرض( يكون بموازاة لوحي الجهاز مي استخدام قطعتي خشب xان السطح الذي يمثل )الطول 140)بمعدل زيدرقائقي اعلى وأسفل النموذج المراد فحصه وبعدها تم تسليط الضغط و الذي ادق الى الحمل المسلط مقدار( في الدقيقة الواحدة لحين سحق الطابوقة ثم سجل 2كغم/سم وتم إيجاد مقدار المقاومة هو معدل ,لكل طابوقة االنضغاط. وتم حساب مقاومة ةقسحق الطابو مقاومة النماذج العشرة. فحص التزهر: 2-3-6 وضاعت كال طابوقاة لكال معمال بشاكل عشاوائي و( طابوقاات مان النمااذج المتبقياة 10تم اخاذ ) على نهايتها)قاعدتها الصغرق( في اناء مسطح غير قابل للصدأ يحتوي علاى مااء مقطار بعماق ( ساام وتركاات فااي حجاارة جياادة التهويااة لماادة ساابعة ايااام مااي اضااافة الماااء المقطاار كلمااا قلااة 2.5) لحين جفاف الماء من االناء وتم ثم تركت العينات بعد ذل في نفس االناء داخل الغرفة كميته. ممحظة التزهر بعد مضي ثمثة ايام من جفاف لماء. تم حساب المساحة الكلية للساطو الساتة اس ابعادها الثمثة كما تم حساب مساحة السطو التي ظهر عليها التزهار يلكل طابوقة وذل بق جااااء فاااي المواصااافة حسااابما ماااي ممحظاااة ناااوع التزهااار الاااذي حصااال.تم تصااانيف اناااواع التزهااار كاألتي :القياسية العراقية المعتمدة معدوم:عندما ال يظهر تزهر .1 %( 10خفيف:عندما تكون مساحة السطح المغطاة بطبقة خفيفاة مان الملاح ال تزياد عان ) 2 من مجموع سطح الطابوقة. احة %( مان مسا50%( وال تزياد عان )10متوساط:عندما تكاون الطبقاة الملحياة اكثار مان ) 3 او تقشر في السطح. تسطح الطابوقة على ان ال يصحب ذل تفت %( ماان سااطح الطابوقااة 50كثيف:عناادما تكااون الطبقااة الملحيااة كثيفااة وتغطااي اكثاار ماان ) -4 او تقشر في السطح. تدون ان يصحب ذل تفت او تقشر في السطح. تكثيف جدًا:عندما تكون الطبقة الملحية كثيفة جدًا ويصحب ذل تفت5 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 00 النتائج و المناقثة -1 القياسااية بموجااب المواصاافةسااوف يااتم تقيمهااا ان نتااائج الفحوصااات التااي سااتعرض فااي هااذه الفقاارة وان العبااارات التااي تشااير الااى تقاايم النتااائج (61/1999)م ق ع 1988( لعااام 25رقاام ) العراقيااة . غيرها يقصد بها هذه المواصفة بالتحديد ما لم يشار الى بموجب المواصفة المعتمدة نتائج فحص المظهر العام 1-3 متقاربة طابوق العراقي تحمل صفات مشتركة وهي لكانت نتائج فحوصات المظهر العام لعينات ا والتي ستعرض بشكل نسب الطابوق السليم ا)عدولذا سوف تعرض بشكل مشتر الى حد بعيد ان المواصفة العراقية القياسية .ايضا على هذه الفحوصات للطابوق االيراني قوهذا ينطب منفصل( اشترطت ان يكون شكل الطابوق منتظم وزواياه قائمة وجوانبه مستقيمة 1988( لعام 25رقم ) في حالة وجود تشقق او تثلم فيجب أن ال تسبب اضعافًا و ضمن حدود التفاوتات المسمو بها يكون الطابوق متجانسًا ان و % من حجم الطابوقة .10لخواص الطابوق وأن ال يزيد التثلم على جيد الحرق خالي من قطي الحصى والحجر والعقد الجيرية وأن ال تقل نسبة الطابوق السليم % من االرسالية.90الخالي من العيوب اعمه عن طابوق العراقي ولجميي عينات الفحص للمعامل موضوع لا ان أظهرت نتائج فحص المظهر العام وزواياه قائمة تقريبا وجوانبه مستقيمة وحسب نسب التفاوت يابنس منتظم كل الطابوقشالدراسة بان خالي ,ذو لون اصفر متجانس نسبيا وجيد الحرقوالطابوق بشكل عام المبينة في فحص االستواء. وان نسب التثلم ان وجدت فهي اقل من من الحصى والحجر والعقد الجيرية وخالي من التشققات ان نسب الطابوق السليم والخالي من العيوب المذكورة اعمه هي كما % من حجم الطابوقة , 10 ولجميي االيرانيطابوق لل. في حين أظهرت نتائج فحص المظهر العام (1الجدول رقم )مبينة في اتماموزواياه قائمة كلياعينات الفحص للمعامل موضوع الدراسة بان شكل الطابوق منتظم تمامافاوت المبينة في فحص االستواء. ذو لون اصفر متجانس وجوانبه مستقيمة وحسب نسب الت تشققات وتحوي بعض عينات الفحصخالي من الحصى والحجر والعقد الجيرية وجيد الحرق. % من 10وان نسب التثلم ان وجدت فهي اقل من .ولكن ضمن النسب التي تسمح بها المواصفة من العيوب المذكورة اعمه هي كما مبينة في حجم الطابوقة , ان نسب الطابوق السليم والخالي . (1الجدول رقم ) نسااابة الطاااابوق الساااليم والخاااالي مااان العياااوب للعيناااات ان يمكااان ممحظاااة (1)رقهههم الجهههدولمااان وهاااي المعتمااادة تقاااي ضااامن حااادود المواصااافة العراقياااة واإليرانااايحوصاااة مااان الطاااابوق العراقاااي فالم .يواإليرانمتقاربة بين الطابوق العراقي 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 07 اكثار انتظاماا مان حياث بينت بان الطابوق االيراناي كاان المظهر العام فحصالعامة لنتائج الان كل افضاال ماان الطااابوق شاابوزواياااه قائمااة تمامااا وجوانبااه مسااتقيمة وأبعاااده اكثاار تجانسااا , ألشااكل عاموة يعود سبب ذل الى قدم اجهزة القص المستخدمة في انتااج الطاابوق العراقاي وقد. العراقي و ان مزم او لسااحب الهااواء لااليساات كافيااة إلعطاااء الكاابس أ قااد تكااون علااى ان طريقااة قااص اللاابن ان عاادم انتظااام االبعااد ياا ثر فااي عملياة عجاان الطاين قااد تكااون غيار متكاملااة او غياار متجانساة. اد مان اساتعمال المااادة الرابطاة وفاي هااذا اضاعاف لقاوة البناااء وتبدياد فاي المااو يزيااد انضاباط البنااء و ذو لاون كاان ان الطاابوق االيرانايكماا .(1991)السهيري، االولية وتبديد في مواد االنهاء الحقاا احاااد ان اللاااون فاااي الطاااابوق يكاااون حصااايلة اكثااار مااان الطاااابوق العراقاااي. اصااافر متجاااانس تماماااا او نوعيااة المعالجااة الحراريااة او المسااتخدم فااي صااناعة الطااابوق العواماال المتعلقااة بتركيااب التااراب حيااااث يتوقااااف لااااون الطااااابوق علااااى وجااااود المعااااادن او اكاساااايدها او .(1991)السهههههيري، ماااادتها اكادت االبحااث (1996)الهدواف ، االمم في الطين كماا يتوقاف علاى درجاة حارارة الفخار ايضاا 950تبلاا تكااون ذات لااون احماار عنااد الحاارق بدرجااة حاارارة بانهااا السااابقة علااى االطيااان العراقيااة درجااة 1050 بساابب تواجااد اكاساايد الحديااد وعنااد رفااي درجااة حاارارة الحاارق الااى ويااة وذلاائدرجااة م yusuf and)لاون االصافراوية يبدأ اللون االحمر يبهت اوال ليبيض ويتحول في النهاية الاى ئم hamadi , 1976) .خاالي ماان ,جياد الحاارق كااان واإليرانايان الطاابوق العراقااي كمااا لاوحظ باا اكثر مان تشققات للطابوق االيراني وتحوي بعض عينات الفحص الحصى والحجر والعقد الجيرية وبصااورة عامااة فااان الطااابوق قااد يحااوي علااى شااقوق مرئيااة واخاارق شااعرية والتااي الطااابوق العراقااي. فااي التربااة او بسااب عاادم عجاان الطااين بصااورة صااحيحة وقلااة وأحجااارتحاادث بسااب وجااود شااوائب ظااام عمليااات التجفيااف والحاارق كمااا يمكاان ان عاادم انت ببالعناياة فااي الكاابس وسااحب الهااواء او بساا فااي حجاام الطابوقااة نتيجااة المتصاااص الرطوبااة ماان تحاادث تحاادث التشااققات بساابب الزيااادة التااي ان وجااود التشااققات فااي الطااابوق يساااعد فااي تعجياال ظهااور التزهاار والتقلياال ماان قااوة تحماال .الجااو .(1991)السهيري، الطابوقة ادنتائج فحص التفاوت في االبع 2-3 . واإليرانينتائج فحص التفاوت باألبعاد للطابوق العراقي (2الجدول رقم )يبين نصت على ان االبعاد القياسية هي 1988( لعام 25ان المواصفة العراقية القياسية رقم ) عن االبعاد القياسية اشترطت ان يكون الحد األعلى للتفاوت باإلبعاد و ملم 75×115×240 يمكن (2)رقم الجدولمن . %4± السم و %3±الطول والعرض :يليالمسمو به كما العينات المفحوصة للطابوق العراقي كانت ضمن الحدود المسمو بها لتفاوت جمييممحظة بان العينات المفحوصة للطابوق االيراني كانت خارج الحدود المسمو بها جميي االبعاد في حين ان 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 07 كون الطابوق االيراني منتج وفق متطلبات ومواصفات محلية الىونرق ان السبب االساسي يعود ولم ينتج وفق االبعاد المحددة في المواصفة القياسية العراقية. فحص استوائية السطح 3-3 .واإليرانيللطابوق العراقي ئية السطحنتائج فحص استوا (3الجدول رقم )يبين اشترطت ان يكون الحد األعلى للتفاوت 1988ام ( لع25رقم )العراقية ان المواصفة القياسية العينات المفحوصة للطابوق جميييمكن ممحظة بان (3الجدول)من .ملم 5في استواء السطح ر عالحدود المسمو بها في تفاوتات استواء السطح اي التق كانت ضمن و االيراني العراقي ان الطابوق االيراني كان افضل من الطابوق العراقي من هذه الناحية حيث كان والتحدب اال وقد يعود هذا الى نفس االسباب ر والتحدب كانت اقل عن قيم التفاوتات في التقااكثر استواء و .2-3الواردة في مناقشة موضوع انتظام الشكل العام للطابوق وتجانس االبعاد الواردة في الفقرة فحص نسبة االمتصاص نتائج 3-4 رة طابوقات واعلى نسبة امتصاص لطابوقة واحدة للنماذج شان نسب االمتصاص لمعدل ع .( 4الجدول رقم )المفحوصة هي كما مبين في أالمتصاصاشترطت ان تكون نسبة 1988( لعام 25المواصفة العراقية القياسية رقم )أن ( وأن 26%,%20,24%ات هي )( طابوق10ج( كمعدل امتصاص ), ب , لألصناف) أ على التوالي.وعليه فان النتائج كحد اعلى ( 28%,%26,%22امتصاص طابوقة واحدة هو) نتاجاعمه تبين بان هنال انتاج معمل واحد يقي ضمن متطلبات الصنف )أ( يقي أربعة معامل وا راني فان النتائج أما بالنسبة للطابوق االي ضمن متطلبات الصنف )ب( بالنسبة للطابوق العراقي. نتاج( بقي ضمن متطلبات الصنف )ت ثمثة معاملاعمه تبين بان هنال انتاج معملين يقي وا . وهذا يعني ان الطابوق العراقي كان افضل من ناحية االمتصاص(جضمن متطلبات الصنف) ان نسبة االمتصاص حيثفي الطابوق العراقي اال ان نسب االمتصاص كانت مي هذا مرتفعة ان زيادة امتصاص الماء في .% من المعامل المدروسة20التي تقي ضمن الصنف أ لم تتجاوز تي تعتمد بدورها على مقدار الكبس اثناء الصني وكمية لالطابوق ينتج بسبب زيادة المسامية وا ةالماء المتبخر من داخل عجينة الطابوق وكذل على درجة الفخر حيث تقل المسامية بزياد كما ان لطبيعة التربة المستخدمة في صناعة الطابوق االثر .(6002رسم وعبد العال،)سالفخر تعد الترب العراقية من مجموعة المونتموريلنات وهي الكبير في تحديد نسبة االمتصاص حيث غنية بمحتواها العالي من الكالسيوم التي يتواجد فيها) بنسبة عالية( بهيئة كاربونات و)بنسبة يئة كبريتات وهذا ي دي الى نسبة عالية من الفقدان بالوزن عند الحرق )نتيجة تحول قليلة( به الكاربونات الى اوكسيد( وهذا يعني الحصول على منتج ذو نوعية رديئة بسب زيادة المسامية 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 71 . (1999)محمد و سعدي، والتي ت دي الى زيادة نسبة االمتصاص وانخفاض مقاومة االنضغاط عمقة بمقدار تحمل الطابوقة حيث ان الطابوق يكون تحمله اقل عندما ممتصان لكمية الماء ال يكون رطبا وكذل يعتبر الماء عامم رئيسيا في حركة االمم التي تسبب التزهر او التفاعل واإلصباغسلبيا مي المادة الرابطة كما وان امتصاص الماء ي دي الى تلف طبقات االنهاء لذا فان لظاهرة نجماداأل ص يكون مصدر قوق تحاول تفتيت الطابوقة عندوكذل فان الماء الممت .(1991ساكو و ليفون، ; 6002)سرسم وعبد العال، امتصاص الماء عمقة بدوام البناء :االنضغاطنتائج فحص 1-5 انضغاط لطابوقة مقاومةرة طابوقات واقل شاالنضغاط لع مقاومةمعدل ( 5الجدول رقم )يبين .دة للنماذج المفحوصة واح اشترطت ان يكون الحد االدنى لمقاومة 1988( لعام 25)رقم العراقية ان المواصفة القياسية ( وأن مقاومة طابوقة 9 ,18,13( طابوقات هي)10ج( كمعدل ),ب ,االنضغاط لألصناف) أ بان هنال انتاج وعليه فان النتائج اعمه تبين على التوالي.(n\mm²) ( 7 ,11, 16واحدة هي) نتاجقي ضمن متطلبات الصنف )ب( ثمثة معامل ت معملين يقي ضمن متطلبات الصنف )ج( وا أما بالنسبة للطابوق االيراني فان النتائج اعمه تبين بان هنال انتاج بالنسبة للطابوق العراقي. نتاج( أيقي ضمن متطلبات الصنف ) معملين و (بنف )يقي ضمن متطلبات الص معمل واحد وا االيراني كان افضل من وهذا يعني ان الطابوق .(جيقي ضمن متطلبات الصنف ) معملينانتاج . ونرق بان السبب االساسي يعود الى طبيعة الترب العراقية المستخدمة ناحية مقاومة االنضغاط ان الترب العراقية الى اشيرحيث , ذل بينت االبحاث السابقة كما في صناعة الطابوق لصناعة الصالحة غير الترب ضمن تصنف الطبيعي بوضعها الطابوق صناعة في المستخدمة تأثير ذو وهو الكالسيوم كاربونات من عالي محتوق ذات كلسية ترب فهي الجيد الطيني الطابوق ان تبين كما. (5891)الحديثي والرمضاني، المنتج الطابوق في المعدنية االطوار تكوين على سلبي تتميز والتي المنتوريلنات مجموعة من هي الطابوق صناعة في المستخدمة العراقية االطيان معظم الكاسيدا وهذه الكالسيوم اكاسيد من عالية نسبة على تحوي وهي الجفاف عند لمنكماش بحساسيتها الصهر حرارة درجة لتخفيضها رظبالن الطابوق صناعة في المستخدمة الترب في مرغوبة غير .(1996)محمد ، فحص التزهر: 3-6 اعلى نسبة تزهر محسوبة للنماذج المفحوصة لكل معمل وتصنيفه حسب ( 6الجدول رقم )يبين (25المواصفة العراقية رقم ) 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 70 اشترطت ان يكون الحد االعلى للتزهر 1988( لعام 25ة القياسية رقم )ان المواصفة العراقي خفيف ولم تشترط نوعا محدد للصنف )ج(.وعليه فان النتائج اعمه تبين ب( هو ,لألصناف) أ نتاج( او ب قي ضمن متطلبات الصنف )أت ثمثة معاملبان هنال انتاج معملين يقي ضمن وا ابوق العراقي.أما بالنسبة للطابوق االيراني فان النتائج اعمه الصنف )ج( بالنسبة للط متطلبات (. وعليه فانه او ب المعامل المدروسة تقي ضمن متطلبات الصنف )أجميي تبين بان انتاج . يمكن القول بان الطابوق االيراني كان افضل من الطابوق العراقي بالنسبة الى فحص التزهر العراقية المستخدمة في صناعة الطابوق على نسبة عالية من ويعود سبب ذل الى احتواء الترب تعاني من مشكلة زيادة نسبة االمم الذائبة العراقية ان معظم الترباالمم المذابة حيث تبين ب )الحديثي في الماء وهذا ي ثر على الطابوق المنتج بشكل سلبي من حيث تكون ظاهرة التزهر لترب المستخدمة في صناعة الطابوق المم القابلة للذوبان لغالبية اان و .(5891والرمضاني، تعد حيث . ( 1991)السهيري، الكلوريدات والنتراتالى باإلضافةكبريتات تكون على شكل االمم القابلة للذوبان بالماء في الطابوق عامم مهما في حدوث التزهر.اذ ان الماء )وهو اوي على االمم يتبخر من سطح الطابوق المعرض العامل االساسي في حركة االمم ( الح للجو م ديا الى تجمي االمم بشكل متبلور على السطح او تحته بقليل مسببا ظهور طبقات من ان مصادر االمم في .(1991ساكو و ليفون، ;6002)سرسم وعبد العال، هذه االمم المستخدمة في ه طينية او المياالطابوق ممكن ان تكون من االمم الموجودة في المواد ال وتحولها الى امم ذائبةالطين التي تتكون من تحلل بعض مركبات اوصناعة الطابوق وقد ينتج التزهر من تكاثف غازات الحرق فكربونات الكالسيوم والمغنيسيوم . (1996)الدواف ، لكن القسم الموجود قرب الى سطح الطابوق اثناء التجفيف و القليلة الذوبان في الماء ال تنتقل الكور( مكونا التزهر, اما الجزء السطح يتفاعل مي الحوامض الموجودة في غاز الحرق )غاز داخل الطابوق فيتفاعل مكونا الكبريتات التي تظهر بعد البناء. ان التزهر يشوه المظهر الموجود ف سطح الطابوقة وخاصة كما ان االمم عند تبلورها تنتفخ وتتمدد وعند حصول هذة الحالة خل الى ان التزهر يتسبب في دفي باإلضافة, غير المحروق منه جيدا تتسبب في تهشيمه وتقشره وتكسر مواد االنهاء الداخلية والخارجية وله تاثير خطير على المادة الرابطة حيث ان امم )مركب ثالث االسمنت الكبريتات الموجودة في طبقة التزهر تتفاعل ببطء مي بعض مركبات من المادة الرابطة كتلة لكالسيومات االلومنيوم(المستعمل كمادة رابطة ويسبب انتفاخه وهذا يجع ويمكن تحسين نوعية الطابوق المنتج من هذه .(1991)السهيري، هشة قابلة لمنحمل والتفتت وي على اقل استخدام تربة من مقالي مرتفعة وتحالناحية باتخاذ مجموعة من االجراءات منها : التربة ان امكن وبزل الماء لعدة مرات , استعمال اقل ما يمكن من لغس , كمية من االمم الماء اثناء عجن الطين , فخر الطابوق بدرجة حرارة عالية , استعمال امم الباريوم مي التربة 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 73 ة من الكبريت الذي يحوي على نسبة عاليعدم استعمال النفط االسود التي يصني منها الطابوق , لقد وجد بأنه و .(1996)الدواف ، في افران الفخر , خلط كميات من الرمل النهري مي الطين يمكن انتاج طابوق خالي من التزهر من الترب العراقية االعتيادية بعد اضافة اطيان الكا ولين التقل (% والحرق وبدرجة حرارة03-03الى الترب المستخدمة في صناعة الطابوق وبنسبة ) حيث لوحظ انخفاضا في نفاذية الطابوق المنتج وبالتالي انخفاضا في نسبة °. ( م 053عن ) امتصاص الماء والذي يعتبر العامل الرئيسي في ذوبان االمم وحركتها. و كذل حصول تحسن في خواص الطابوق المنتج بعد اضافة اطيان الكا ولين من حيث المظهر العام وزيادة ان .(6009،)علي اضافة كلف عالية وذل لتوفره محليا ذل ال يتطلب ووقوة التحمل الكثافة الممحظات التقنية المقدمة من قبل اتحاد صناعة الطابوق االمريكي تناولت في جانب منها موضوع التزهر حيث تصف االلية التي ت دي الى تكونه و المصادر المحتملة لألمم القابلة التي تساعد على حدوثه مي مجموعة من التوصيات واإلجراءات التي ت دي للذوبان والظروف (. (brick industry association, 2006الى التقليل من احتمالية حدوثه او مني ظهوره العام للنماذج وتصنيفها حسب متطلبات المواصفة العراقية مالتقيي 3-7 ضوع الدراسة وتصنيفها حسب متطلبات المواصفة التقييم العام للنماذج مو (7الجدول رقم )يبين .1988( لعام 25العراقية القياسية رقم ) من المعامل العراقية ومعمل واحد من ثمثة معاملبان هنال انتاج (7الجدول رقم )يبين المعامل االيرانية التي تم اخذ نماذج من انتاجها توضي ضمن الصنف )ب( والبقية تصنف االيرانية التي وضعت ضمن الصنف لي ممحظة ان انتاج جميي المعامم ضمن الصنف )ج( وحسب ب او ج حسب الجدول اعمه كانت خارج حدود نسب التفاوت في االبعاد المسمو بها فضل ضمن متطلبات وهذا يعني ان الطابوق العراقي هو اال. (2ما موضح في الجدول رقم ) متطلبات يي المعامل العراقية المدروسة كانت خارج ومي هذا فان انتاج جمالمواصفة العراقية اضافة ولقد وجد بان . 3-6و 3-5 و 3-4 اتي بينت في الفقرات لألسبابالصنف أ وذل الطابوق صناعة في الداخلةالعراقية التربة الى الناعم المكسر الزجاجو الزجاجمسحوق نفايات ومعاير االنضغاط مقاومة زيادة خمل من للطابوق المنتج الفيزيائي الخواصيحدث تحسن في مسحوق اضافة انحيث تبين ب .المنتوج جودة من يحسن مما االمتصاصنسبة وتقليل الكسر يحسن خواص الطابوق المنتج %5او% 03 بنسبة 53 رقم منخل من العابر الناعم الزجاج حميد ) الطيني ابوقللط العراقية القياسية للمواصفة طبقا أ صنف ضمن هتصنيف يمكن بحيث .( 6011والطويل ، 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 72 االستنتاجات4 التالية االستنتاجات إدراج يمكن العمل هذا في عليها الحصول تم التي العملية النتائج خمل من الشكل حيث من انتظاما اكثر كان االيراني الطابوق بان بينت العام المظهر فحص نتائج ان -1 متجانس اصفر لون ذو وهو .العراقي الطابوق من افضل بشكل تقيمةمس وجوانبه تماما قائمة وزواياه الحصى من خالي.الحرق جيد كان واإليراني العراقي الطابوق ان. العراقي الطابوق من اكثر تماما الطابوق من اكثر تشققات االيراني للطابوق الفحص عينات بعض وتحوي الجيرية والعقد والحجر السليم الطابوق ونسب .الطابوقة حجم من% 10 من اقل فهي وجدت ان التثلم نسب وان .العراقي التي النسب ضمن وهي واإليراني العراقي للطابوق بالنسبة% 90 من اكثر هي العيوب من والخالي . العراقية المواصفة بها تسمح لمحددة ان الطابوق العراقي افضل من االيراني من حيث نسبة التفاوت عن االبعاد القياسية ا -2 العينات المفحوصة للطابوق العراقي ضمن الحدود ييجم حيث كانت ألعراقيةفي المواصفة العينات المفحوصة للطابوق االيراني كانت خارج جمييالمسمو بها لتفاوت االبعاد في حين ان ان مقاسات الطابوق تختلف من بلد ألخر حسب المواصفات مي ممحظة الحدود المسمو بها. د. البل في ذل سائدةال في بها المسمو الحدود ضمن كانت االيراني و العراقي للطابوق المفحوصة العينات جميي ان -3 العراقي طابوقال من افضل كان االيراني الطابوق ان إال والتحدب رعالتق اي السطح استواء تفاوتات .استواء اكثر كان حيث الناحية هذه من معمل انتاج بان تبين فقد االمتصاص نسبة حيث من االيراني من افضل العراقي الطابوق ان -4 نتاج( أ) الصنف متطلبات ضمن يقي واحد بالنسبة( ب) الصنف متطلبات ضمن يقي معامل ةأربع وا معامل ثمثة انتاج هنال بان تبين اعمه النتائج فان االيراني للطابوق بالنسبة أما .العراقي للطابوق نتاج( ب) الصنف متطلبات ضمن تقي (.ج) الصنف متطلبات ضمن قيت معملين وا انتاج هنال بان النتائج بينت حيث افضل االيراني الطابوق فكان االنضغاط مقاومة ناحية من -5 نتاج( ب) الصنف متطلبات ضمن قيت معامل ثمث ( ج) الصنف متطلبات ضمن يقي معملين وا ضمن يقي معملين انتاج هنال بان فتبين االيراني للطابوق بالنسبة أما العراقي للطابوق بالنسبة نتاج (أ) الصنف متطلبات نتاج( ب) الصنف متطلبات ضمن يقي واحد لمعم وا ضمن يقي معملين وا (.ج) الصنف متطلبات ن تبيأن نتائج فحص التزهر أوضحت بان الطابوق االيراني افضل من الطابوق العراقي حيث -6 نتاجبان هنال انتاج ثمثة معامل تقي ضمن متطلبات الصنف )أ او ب( معملين يقي ضمن وا 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 77 أما بالنسبة للطابوق االيراني فان النتائج تبين , متطلبات الصنف )ج( بالنسبة للطابوق العراقي .بان انتاج جميي المعامل المدروسة تقي ضمن متطلبات الصنف )أ او ب( بان هنال ود المواصفة العراقية المعتمدة على النماذج المدروسة فيتضح عند تطبيق كامل بن -7 انتاج ثمثة معامل من المعامل العراقية ومعمل واحد من المعامل االيرانية التي تم اخذ نماذج من أذا ما تم استثناء شرط انتاجها توضي ضمن الصنف )ب( والبقية تصنف ضمن الصنف )ج( انتاج جميي المعامل االيرانية التي وضعت االبعاد القياسية حيث ان التفاوت في االبعاد عن كانت خارج حدود نسب التفاوت في االبعاد المسمو بها وفق المواصفة ضمن الصنف ب او ج .فضل ضمن متطلبات المواصفة العراقيةان الطابوق العراقي هو اال . وهذا يعنيالمعتمدة من ناحية التقييم العام. أ الصنف متطلبات خارج كانت المدروسة العراقية لالمعام جميي انتاج ان -8 5 -التوصيات بالنظر لمحدودية هذه الدراسة فإننا نرق بأن الموضوع يحتاج إلى المزيد من البحوث المستقبلية , ب :و لذل نوصي يرانية عراقية معامل لتشمل الموضوع عن أخرق دراسات إجراء -1 .اكبر اعداد وذات اخرق وا ت دي التي المعوقات ومعالجة العراق في الطابوق انتاج بواقي للنهوض مستقبلية دراسات اجراء -2 . العراقي المنتج نوعية تردي الى للمواصفات المطابق غير المنتج دخول ومني المستورد الطابوق نوعية على الرقابة فرض ضرورة -3 .العراقي المستهل لحماية صفةاالمو بنود حسب هاوتصنيف المستوردة المنتجات وتقيم المصادر : : 1988(/24الجهاااز المركاازي للتقياايس والساايطرة النوعيااة , المواصاافة القياسااية العراقيااة رقاام ) 1 ( , بغداد , العراق.1988طرق اخذ نماذج وفحص طابوق البناء , ) : 1988(/25القياسااية العراقيااة رقاام ) الجهاااز المركاازي للتقياايس والساايطرة النوعيااة , المواصاافة -2 ( , بغداد , العراق.1988الطابوق المصنوع من الطين , ) الحديثي , د. عادل ابراهيم و الرمضاني , خيرية , صمحية الترب العراقية لصناعة طابوق -0 ( , نشرة مركز بحوث البناء , مجلس البحث ألعلمي بغداد , العراق.0095البناء الطيني , ) ( , مطابي أوفسيت الزمان , بغداد 1982, ) 6الدواف , يوسف , المباني والمواد البنائية , ط -0 , العراق. ( , دار ابن االثير للطباعة 1972, ) 3الدواف , يوسف , فحص المواد البنائية , ط -5 جامعة الموصل , مطبعة شفيق , بغداد , العراق. -والنشر 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 77 مطبعة كنعان , -( , اليقظة العربية 1991, ) 1لمباني , طالسهيري , عاطف , انشاء ا -6 بغداد , العراق. ( , وزارة التعليم العلي والبحث العلمي , 1985النعيمي , سرمد فخري , مواد االنشاء , ) -7 بغداد , العراق. على الزجاج نفايات إضافة حسين , تأثير الصاحب و الطويل , مرتضى عبد حميد , مجيد -9 , هيئة 6, العدد 20( , مجلة التقني , المجلد 2300المحلي , ) للطابوق الفيزيائية اصالخو التعليم التقني , بغداد , العراق. ( , وزارة التعليم العالي والبحث 1983ساكو, زهير و ليفون , آرتين , إنشاء المباني , ) -0 العلمي , بغداد , العراق. دار اليازوري , ( , 2006), سعيد , المواد اإلنشائية , ي, جمل بشير و عبد العال سرسم -03 عمان, االردن. , (1985) , سعيد و عبد الجبار , مي تحسين , فحوص المواد االنشائية , عبد العالي -00 العراق. وزارة التعليم العلي والبحث العلمي , بغداد , ف في اللبن الجاف وظاهرة التزهر علي , هند باسل , دراسة أسباب زيادة نسبة التل -02 , الجامعة 02, العدد 27( , مجلة الهندسة و التكنلوجيا, المجلد 2330للطابوق الفخاري, ) التكنولوجية , بغداد , العراق. 0000 , خواص بعض االطيان العراقية عند الحرق , لمى , ريا ياسين و سعدي , محمد -10 العراق. , بغداد , التكنولوجيةهندسة الحراريات , الجامعة ,مشروع دبلوم عالي في تكنلوجيا , (0072) تحريات لتحسين نوعية الطابوق المحلي , , زين العابدين ر وف , محمد -00 العراق. , وقائي الم تمر العلمي االول , مجلس البحث العلمي , بغداد 15brick industry association , technical notes on brick construction (23a): efflorescence causes and prevention , 2006 , reston , virginia , usa , www.gobrick.com. 06barry, r , the construction of buildings – vol.1, (1978), 3ed-elbs ed., crosby and lockwood & son ltd, london. 17yusuf, sadiq and hamadi, aziz, report of clay samples from tikrit , brc, srf, october 1976, ap28/76, baghdad, iraq. http://www.gobrick.com/ 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 77 ( نتائج فحص المظهر العام للطابوق العراقي واإليراني)نسب الطابوق السليم والخالي 1جدول ) من العيوب( واإليراني( نسبة التفاوت باألبعاد للطابوق العراقي 2جدول ) الطابوق السليم % نسبة اسم المعمل المنشأ 93 المحاويل 95 القيروان العراقي 94 الشيحاني 94 ابو رياض 92 قاسم العكيلي 92 دوستان 94 اصفهان اإليراني 96 قبانجي 94 صادقيان 93 فخاري نيا اوت في االبعاد نسبة التف معدل اسم المعمل المنشأ ((mmالطول معدل (mmالعرض) معدل (mm)االرتفاع )عن االبعاد القياسية( % السم العرض الطول 2.70.9+ 0.4+ 33 111 241 المحاويل 2.7+ 0.9+ 0.0 33 111 242 القيروان العراقي 4.0+ -2.1 0.437 112 233 الشيحاني -1.3 +1.3 1.3+ 34 113 243 ياضابو ر 1.3+ 0.90.0 76 114 240 العكلي قاسم -5.3 2.6+ 1.331 118 237 دوستان 4.0-3.7 -5.7 32 121 221 اصفهان اإليراني -5.3 9.66.731 104 224 قبانجي 4.06.15.072 108 228 صادقيان 7.1-12.1 -7.3 70 121 222 فخاري نيا 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 70 واإليراني( استوائية السطح للطابوق العراقي 3جدول ) ( نسب االمتصاص لمعدل عشرة طابوقات واعلى نسبة امتصاص لطابوقة واحدة 4جدول ) للنماذج المفحوصة التحدب ) ملم ( التقعر ) ملم ( اسم المعمل المنشأ 2-4 2-3 المحاويل 1-2 1-2 القيروان العراقي 1-4 1-3 الشيحاني 1-2 1-3 ابو رياض 1-3 1-3 قاسم العكيلي 1-2 1-2 دوستان 1-2 1-2 اصفهان اإليراني 1-2 1-2 بانجيق 1-2 1-2 صادقيان 1-2 1-2 فخاري نيا %فحص االمتصاص امتصاص طابوقة واحدة طابوقات (10معدل) اسم المعمل المنشأ )اعلى قيمة مسجلة( 21.8 20.6 اويلالمح 21.5 19.7 القيروان العراقي 24.7 21.3 الشيحاني 23.6 22.5 ابو رياض 21.6 20.5 قاسم العكيلي 24.9 23.2 دوستان 23.1 26.0 اصفهان اإليراني 24.6 23.4 قبانجي 25.8 24.5 صادقيان 23.4 22.3 فخاري نيا 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 77 واإليرانيللطابوق العراقي االنضغاطحص مقاومة ( نتائج ف5جدول ) واإليراني( النتائج النهائية لفحص التزهر للطابوق العراقي 6جدول ) (n\mm²) اسم المعمل المنشأ فحص االنضغاط (10( طابوقات معدل طابوقة واحدة )اقل قيمة مسجلة( 12.7 13.9 المحاويل 13.4 16.6 القيروان العراقي 14.3 17.2 الشيحاني 12.5 14.1 ابو رياض يليقاسم العك 13.9 13.1 10.5 12.4 دوستان 18.3 19.7 اصفهان اإليراني 22.8 22.4 قبانجي 14.2 17.8 صادقيان 10.1 11.5 فخاري نيا نسبة التزهر اسم المعمل المنشأ %( ( حد اعلى ر نوع التزه كثيف 60 المحاويل خفيف 7.0 القيروان العراقي خفيف 8.5 الشيحاني متوسط 15.2 ابو رياض خفيف 9.1 قاسم العكيلي خفيف 3.7 دوستان خفيف 9.7 اصفهان اإليراني خفيف 7.1 قبانجي خفيف 7.1 صادقيان خفيف 6.5 فخاري نيا 3102لسنة -المجلد السادس العدد الثالث مجلة القادسيه للعلوم الهندسيه 77 م للنماذج موضوع الدراسة وتصنيفها حسب متطلبات المواصفة العراقية رقم ( التقييم العا7جدول ) 1988( لعام 25) نوع الفحص المنشأ اسم المعمل االمتصاص )حد اعلى( % االنضغاط دنى()حد ا (n\mm²) التزهر الصنف حسب متطلبات المواصفة العراقية ( 10معدل) طابوقات امتصاص طابوقة واحدة ( 10معدل) طابوقات انضغاط طابوقة واحدة حد اعلى ج كثيف 10.7 13.9 21.8 20.6 المحاويل ب خفيف 13.4 16.6 21.5 19.7 القيروان العراقي ب خفيف 14.3 17.2 24.8 21.3 الشيحاني ج متوسط 10.5 14.1 23.6 22.5 ياضر ابو ب خفيف 13.1 13.9 21.6 20.5 قاسم العكيلي ج خفيف 10.5 12.4 24.9 23.2 اندوست ج خفيف 18.3 19.7 27.1 26.0 اصفهان اإليراني ب خفيف 20.8 22.4 24.6 23.4 قبانجي ج خفيف 14.2 17.8 25.8 24.5 صادقيان ج خفيف 10.1 11.5 23.4 22.3 فخاري نيا \(microsoft word \\322\\355\\344\\310 \\330\\307\\341\\310\) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 mathmatical modeling of mass transfer from an immersed body to a fluidized gas bed zainab talib abidzaid al-sharify al-mustansiryiah university/college of engineering environmental engineering department iraq baghdad /bab-almuthem/p.o. box 14150 zainab_talib2009@yahoo.com abstract: fluidization process is widely used by a great assortment of industries worldwide; one of these processes is the mass transfer from an immersed body to a fluidized gas bed. this work presents an experimental study of a continuous gas-solid fluidized bed with a porous material placed at the bottom of the column to support the packing material. sand-air-naphthalene system has been used in this work. sand with sizes distributed between 75-250 microns was used as solid fluidizing particles and air was used for fluidization in a 70 cm height and 8 cm inside diameter fluidization column. naphthalene was selected for this study as the immersed object, this have been done by making a spheres of wood of 2.9 cm outside diameter and coating this spheres wood with naphthalene by dipping this spheres into a bath of molten naphthalene (at about 900c). an empirical correlation was developed for mass transfer of naphthalene vapor into air-sand fluidized bed by using experimental data of many variables such as temperature, air velocity, and sand particle size. the experimental results of the mass transfer in the present work have been compared in curve in yokota,s coordinate with many documented experimental literatures data. the comparison gave a very good agreement, and show that sherwood number increased slowly with the increase in gas velocity at constant surface temperature and particle size. key words: fluidization, mass transfer, sand-air-naphthalene system, ziegler equation, sherwood number, minimum fluidizing velocity, mass transfer coefficients. غاطس الى طبقة غازية مميعة جسمنتقال المادة من النمذجة الرياضية الشريفي عبدزيد زينب طالب الجامعة المستنصرية كلية الھندسة قسم ھندسة البيئة :الملخص سم ان عملية التميع واسعة االستعمال في الصناعات العالمية المتعددة واحدة من هذه العمليات هي انتقال المادة من ج الصلب مع مادة مسامية وضعت -لغازا للتميع المستمر لنظام هذا العمل يقدم دراسة تجريبيةان .غاطس الى طبقة غازية مميعة ان الرمل المستعمل كجسيمات الصلب .نفثالين-هواءتم في هذا العمل استخدام نظام رمل. مواد الحشوةفي أسفل العمود لدعم تم استخدام عمود تميع زجاجي .ان سائل التميع كان الهواء، مايكرون ٢٥٠ ٧٥ة تتراوح بين المتميع استخدم بأحجام مختلف حيث تم طالء كرات خشبية ، تم في هذه الدراسة استخدام المادة المغمورة وهي النفثالين. سم 8سم وبقطر داخلي 70بأرتفاع تم تطوير . درجة سليزية ٩٠ن المنصهر بدرجة حرارة حوالي سم وذلك بإنزال هذه الكرات في حمام النفثالي ٢.٩قطرها الخارجي al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 وذلك بدراسة العملية لعدة ، عالقة رياضية تربط معامل إنتقال المادة لبخار النفثالين الى الطبقة الغازية المميعة من الهواء والرمل ألنتقال المادة في العمل الحالي تمت ان النتائج التجريبة. معدل جريان الهواء وحجم الدقائق،درجة حرارة السطح ك متغيرات وتم وضعها في رسومات على احداثيات ، هرت مطابقة جيدة جداظوهذه المقارنة ا. مقارنتها مع التجارب العملية الموثقة علميا .حيث تم ايجاد ان رقم شيروود يتزايد ببطء مع زيادة سرعة الغاز بثبوت حرارة السطح والجسيمات، يوكوتاس notations units notations symbols mole /m3 concentration at the surface. = cs mole / m3 bulk concentration. = cb relative and mean relative mass capacity respectively = cm , mc kg / kg specific mass capacity of gas and particles respectively = cmf ,cms m2 / s molecular diffusivity in a gas = df m2 / s effective and mean effective diffusivity in a particle respectively = ds , sd m2 /s diffusivity of transferable component and at 00c respectively. = dv, dv0 m diameter of the bed. = d m fluidizing particle diameter. = dp m/s2 gravitational force. = g kg /m2. s gas mass velocity. = g kg /m2. s gas mass minimum velocity. = gmf kg / m2.s surface-to-inert bed mass transfer coefficient = ky' kg / m2.s surface-to-bubble mass transfer coefficient = kyb' kg / m2.s surface-to-packet mass transfer coefficient = kyp kg / m2.s surface-to-packet mass transfer coefficient for cms=0 = kyp' m/s mass transfer coefficient. = kg m length of the column = l kg particle mass 3 / 6s s sm dπ ρ= = ms m3 / kg mass capacity of particles = ms kg/m2.s total surface-to-bed mass flux = n mm hg bed pressure drop. = ∆p mm hg saturation partial pressure. = ps reynolds number based on the diameter of the inert particles. = rep m2. s /kg mass transfer packet and contact resistance respectively = rmp, rmw sherwood number. kg ds / dv = sh sherwood number in empty bed. = she sherwood number in packet bed. = shp 0c temperature = t 0c saturation partial temperature. = ts m/s minimum fluidizing velocity. = umf m/s gas velocity = u kg/kg concentration of gas (mass of transferred substance per unit mass of inert gas) = y greek letters µ = viscosity kg/ s.m µo = viscosity of air at 0c kg/ s.m ρ = gas density. kg/m3 ρp = particle density. kg/m 3 , sfρ ρ = gas and solid density respectively kg/m 3 ψ = sphericity. τ = time s bb ττ , = bubble residence contact time and its mean value respectively s al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 pp ττ , = packet residence contact time and its mean value respectively s ε = porosity εp = packet porosity subscripts b bubble f gas m mass (minimum) p packet s solid(particle) introduction: fluidized beds are commonly employed in chemical, biochemical and petrochemical industries in processes such as hydrocarbon cracking, drying of solid particles, combustion and gasification of coal and biomass, synthesis reactions and coating of particles. gas-solid fluidized systems are characterized by temperature uniformity and high heat transfer coefficient due to the intense mixture of the solid material with the gas bubbles normally present (pécora and parise, 2006). a number of correlations for mass transfer in fluidized beds have been proposed, most of these involve a single-line relationship between reynolds number and the product of sherwood number by some power of schmidt number (wankhede, 2009). resnick (resnick, 1949) calculated the mass transfer coefficient of naphthalene crystals of five different sizes ranged from 250 to 1000 microns in air, hydrogen, and carbon dioxide at a temperature of 298k and rates between 0.01 and 1.5 kg/m2.s. gamson (gamson, 1951) utilized the available mass transfer data for packed and fluidized beds related the mass transfer modulus to the modified reynolds group. gupta and thosad (gupta and thosad, 1962) correlated the mass transfer factor with the conventional reynolds number utilizing all the available data. markova and martyushin (markova and martyushin, 1965) studied the effect of fluidized particle size on mass transfer coefficient with particle diameter of 0.565, 0.488 and 0.347 mm. they concluded that the increasing air velocity increases the mass transfer coefficient. shirai (shirai, et al., 1966) studied heat and mass transfer between fluidized bed and surface of single sphere fixed in the bed. sand was employed as fluidizing particles for mass transfer study and the solid sphere was made of brick and the system used is air-water system. they found that the value of sherwood number is only 1.5 times that for mass transfer between particles and fluid. ziegler and holmes (ziegler and holmes, 1966) studied mass transfer from fixed surface to gas fluidized beds. mass transfer coefficients were measured for the diffusion of water vapor from a saturated porous sphere into various air-fluidized beds of solid particles. naphthalene diffusion from coated flat plate into fluidized beds was also studied. gunn (gunn, 1987) studied the mass transfer in gas-solid fixed and fluidized beds operated in a wide range of velocities and porosities. he developed a theoretical correlation that expresses the mass transfer between the particles and fluids processes. kaneko (kaneko et al., 1999), rhodes (rhodes et al., 2001) and kafui (kafui et al., 2002) studied the general characteristics of a fluidized bed, such as the gradual change in particle characteristics and size distribution in the bed, and also studied the impact of inter particle forces on fluidization. schmidt and renz (schmidt and renz, 2005) investigate numerical analysis of the heat transfer between fluidized bed of mono-dispersed glass beads and an immersed heater tube. an eulerian approach has been used for the solution of the mass, momentum and energy equations of both phases. pécora and parise (pécora and parise, 2006) presents an experimental study of a continuous gas-solid fluidized bed with an immersed horizontal tube. silica sand of 254µm diameter was used as solid particles and air was used for fluidization in a 900mm long and 150mm wide heat exchanger. an empirical correlation for the heat transfer coefficient was proposed as a function of solid particle and gas mass flow rate, number of baffles and gas velocity. wankhede (wankhede, 2009) study the effect of surface temperature on average heat transfer coefficients in a sound assisted fluidized bed of fine powders. he found that for both coarse grained and fine particles, the heat transfer rates can be improved by increasing al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 the surface temperatures. he presents the data as a function of excess air velocity and sound pressure level. the objective of this work is to: 1writing a mathematical model for mass transfer from an immersed body to a gas fluidized bed depending on variables affecting the mass transfer. 2study the effect of different factors on the gas-solid system, such as fluid properties, fluidized properties, and nature of the flow, as well as the effect of each one on the others. 3determine the dependence of mass transfer coefficient on fluidized bed variables. many variables effect mass transfer have been investigated such as: air velocity, sphere surface temperature, size of fluidizing particles and sphere size. 4predicate the mass transfer coefficient from the knowledge of mass transfer coefficient in the absence of fluidizing particles, plus a term that describes the effect of fluidizing solid particles on transfer rate coefficients. minimum fluidizing velocity when the gas is passed upwards through a fluidized bed unrestrained at its upper surface, the pressure drop increases with gas velocity increasing, the drag on an individual particle excess the force exerted by gravity. then an excess pressure is required to free the particles that are interlocked at the fluidized state and theoretical pressure drop. the velocity at the point that the pressure drop falls back is called the minimum fluidizing velocity (umf) (gupta and sathiyamoorthy, 1999). leva (leva et al., 1951) worked with round and sharp sands of 0.05-0.40 mm using 0.1 m diameter with various depths fluidized by air. he noted that the smaller particles require an extra of energy for fluidization. the wen and yu produced an empirical correlation for umf for gas fluidization. wen and yu (wen and yu, 1966) correlation is often taken as being most suitable for particles larger than 100 µm, whereas the correlation of baeyens and geldart (baeyens and geldart, 1974) is best for particles less than 100µm, which is shown in eq. 1: 1.8 0.934 0.934 0.87 0.066 ( ) 110 p p mf d g u ρ ρ µ ρ − = (1) model for mass transfer in fluidized bed the process of mass transfer from an immersed body to a gas fluidized bed has not yet been intensively investigated. to describe the process mathematically baskakov (baskakov and suprun, 1970) and prozorov (prozorov, 1976) assumed that mass is transmitted from the surface by packets of particles and by gas bubbles as follows: (1 ) y yp yb k f k f kο ο′ ′ ′= − + (2) where: b pb f ο τ τ τ = + (3) in contrast to heat transfer theory where the heat within a packet is transferred through gas and particles and the accumulation of heat within particles plays a dominant role. these workers assumed that mass within a packet is transferred only by gas between particles occurs. thus the mass transfer coefficient to a packet was found to be (markova and martyushin, 1965; baskakov and suprun, 1972; baskakov et al., 1973): 1/ 2 2 fyp p d k ρ πτ′         = (4) 1/ 2 2 bfyb b d k ρ πτ′         = (5) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 it must be remembered that all the above considerations apply to an inert fluidized bed (baskakov, 1974). if adsorption of a transported substance onto the particles takes place the mass transfer coefficient rises and the ratio (ky/kyf ) may then reach values from 3 to 15 (ziegler and holmes, 1966). for such cases, on the basis of the packet theory and allowing for mass accumulation on particles, yokota (yokota et al., 1975) derived the following expression: 1/ 2 (1 )p s s pf yp f p d m k ε ρ ε ρ τ         − = (6) eq. 6 transformed into the dimensionless form, as shown below: 1/ 22(1 )p s s p pf m l sh d ε ε ρ τ         − = (7) in this work the mass capacity process was investigated and described on the basis of the modified packet model including the mass contact resistance. for the contact resistance control region the alternative simplified packet model was developed. in order to derive the simplified packet model equations, two assumptions are made: 1for sufficiently short packet contact times which correspond to vigorous fluidization and for relatively large particles, only the first layer of particles, i.e. those in contact with the surface, participate in surface-packet mass transfer. 2during the time that a packet remains at the surface, a particle in the first layer adsorbed to the surface. dimensional analysis: the dimensionless group, y, is a function of all the variables and dimensionless constant which take into account the influence of particles motions. these factors may be arranged in a suitable form of dimensional analysis using buckingham’s π theorem (buckingham, 1914), such as: ( , , ( ), , , ( ), )p p mfy f d g g gψ ρ ρ ρ µ= − − (8) (9) the common groups for mass transfer are sherwood number, schmidt number and reynolds number. in buckingham’s π theorem, the dimensions of a physical quantity are associated with mass, length and time, represented by symbols m, l and θ respectively, each raised to rational powers. the number of dimensionless groups obtained from the dimensional analysis are equal to the number of variables, n=5, minus the number of fundamental dimensions, r=3, and hence two dimensionless groups will be obtained. in term of fundamental dimensions: (10) from these results we obtain (11) 2 ( ) ( ) ( )( ) [ ] [ ] ( ) p p pb emf mf g d d g g y g g ρ ρ ρ ψ ψ µ −− −= − (12) from the above equation, one can notice that the first term is the invert of froude number (fr) and the second is the modified reynolds number (re). 2 6 2 2 [ ] [ ] [ ] [ ] [ ]1 a b c d e m m l m l ll l θθ θ = 2[ ] [( ) ] [ ] [ ] [ ]e b b b e b ep p mfy d g g gψ ρ ρ ρ µ − − − −= − − [ ] [( ) ] [ ]a b c d ep p mfy d g g gψ ρ ρ ρ µ= − − al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 experimental set-up and method sand-air-naphthalene system has been used in this work. sand was employed as fluidizing particles, which can be regarded as a non-absorptive material. a sand bed material was employed in this investigation with three different particle sizes, with range of 75-250 micron, in order to get a smooth fluidization. the properties of sand particles used in this work are shown in table 1. the immersed object used has a spherical shape of 2.9 cm outside diameter made of wood, which was coated with hard smooth surface of naphthalene. this was done by dipping the spheres into a bath of molten naphthalene at about 90°c. the immersed object was fixed in the center of the column by suspending it with a steel rod. the spherical shape was used in order to minimize the dead zone around the immersed object, and because spherical shapes have many applications in the industrial. a photographic picture of the apparatus used is shown in figure 1. the experimental system, as outlined in figure 2, consists of the main components: fluidization column, air compressor, air flow meter, u-tube manometer, bed material (sand), immersed work piece, heating equipment (heating element, variac), and temperature measurement device. the fluidization column was made of glass column (q.v.f) 8 cm inside diameter and 70 cm height. a porous material was placed at the bottom of the column to support the packing material. air compressor was used to supply air with a surge tank to store the air and minimize the fluctuation. an automatic regulator in the compressor was used to regulate the pressure of the air inside the tank. the amount of air which left the compressor was controlled by the use of the tank and valve. a calibrated air flow meter was used to measure the air flow rate which entered the column. the range of the air flow meter is 0-16 m3/hr. the pressure drop across the bed was measured by the use of u-tube manometer which made of glass with total length of 0.75 m. the manometer was placed on a wide sheet of wood with a measuring tape for the measurement of the level difference of the liquid (water) inside the tube. an electrical heater placed inside 2" q.v.f. glass tube has been used as the heating equipment. the variation in heat supplied from the heater was controlled by the use of a variac connected directly to the heater. two thermocouples were used for temperature measurement; the thermocouples were located in two different locations in order to measure the temperature about 3 cm under and above the spheres. these thermocouples were connected to digital readers that show the value of temperature. experimental procedure the pressure drop of the bed was determined by subtracting the pressure drop of distributor from total pressure drop that are found for a range of superficial gas velocities after loading known weight of sand particles having known diameter into the bed to a static level of 30 cm. curves of pressure drop across the bed versus superficial gas velocity are shown in figures 3, 4, 5 and 6. mass transfer coefficient value in empty bed has been determined experimentally, by placing two thermocouples and other devices and connected them to the column. the compressor started blowing air into the tank until it reached the desired pressure to turn the compressor off by the automatic regulator. the tanks valve was turned on. the air flowed through the rotameter to the bed until rotameter read a constant desired value of the air flow rate. at the same time the heater was turned on for the desired power which was controlled by the use of the variac. the measurements of the pressure drop across the bed were made by the use of the u-manometer. when the conditions reach to steady state (constant flow rate and constant temperature), the coated sphere was lowered inside the column 15 cm above the distributor surface. every 5 minutes, the sphere was taken out of the bed and the change of weight was measured by digital balance. this have been repeated for arrange of air superficial velocities and a range temperatures. the mass transfer coefficient value from the sphere sand to the fluidized bed has been determined experimentally, by weighting a quantity of sand and poured it into the column from the top for a known and constant height of 30 cm for all runs carried in the work. two thermocouples in their place were connected to the column. the compressor started blowing air into the tank until it reached the desired pressure to turn the compressor off by the automatic regulator. the tanks valve was turned on. the air flowed through the rotameter to the bed until rotameter read a constant desired value of the air flow rate. at the same time the heater was turned on for the desired power that was controlled by the use of the al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 variac. when conditions reach to steady state (constant flow rate and constant temperature); the coated sphere was lowered inside the column 15 cm above the distributor surface. results and discussion: a set of experiments at different air velocities and different temperatures were performed for mass transfer in empty bed (air stream only), to check the results with previous works. operational conditions and experimental results for mass transfer coefficient for each experimental test are presented in table 2 and 4. from table 4 it can be seen clearly that experiments were carried out at temperature below 70℃, to avoid naphthalene melting. a set of experiments were performed to determine the value of mass transfer coefficient from the sphere to the fluidized bed, the experimental conditions and results for this experiments are listed in table 3 and 5. the air velocity is chosen to be within the range (1-1.4) umf, because this range of flow is usually used in industrial practice. the particle size of sand was selected to be as fine particles in order to get a smooth fluidization. ntal resultscorrelations of the experime many variables are influence mass transfer coefficient such as diffusivity of the active component through the fluid, superficial flow rate of the fluid, density and viscosity of the fluid, and shape and size of the spaces between the particles in the bed. a number of assumptions were made to get accurate relationship of the variables influence on mass transfer coefficient: 1neglect the abrasion effects and assume the weight loss of naphthalene is mainly due to evaporation. 2void fraction of fluidizing sand particles equals the void fraction at minimum fluidizing velocity. 3partial pressure of naphthalene at the surface everywhere equal to the saturation partial pressure of vapor at the surface temperature of the solid sphere, the partial pressure of naphthalene at the bulk of air stream was equal to zero. change in surface area of the sphere along the experiment was neglegted. surface temperature of the solid sphere everywhere equal to the average value of the temperature reading of the thermocouples below and above the sphere. the experimental results must be correlated by: 1-the viscosity of air can be calculated from eq.13, where µo is the viscosity of the air at 0℃ which equals to 0.017 in centipoises and n equals to 0.677 (perry, 1973): 273 n t ο µ µ       = (13) 2experimental value of mass transfer coefficients was calculated from eq. 14, in which cb is equal to zero (perry, 1973, prins et al., 1985): ( )g s bn k c c= − (14) 3the correlation for diffusivity of naphthalene vapor in air with temperature is made by eq. 15, where the diffusivity of naphthalene vapor in air at 0℃ was taken equal to 0.0513 cm2/s and m=1.823(perry, 1973): 273 m dv t dv ο       = (15) 4vapor pressure of solid naphthalene is given by equation 16 where ps in mhg and ts in k, for the range of (0-80℃) (perry, 1973): (16) 5values of sherwood number for mass transfer from the sphere to the bed of fluidized particles were calculated by the eq. 17; in which f(y) describes the effect of particles motion on transfer rate, and y is a dimensionless group determined by dimensionless analysis (perry, 1973): 3729.3 log 11.450s s p t = − + al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 ( )esh sh f y= + (17) 6the value of sherwood number for mass transfer in empty bed calculated from equ.18, where c1, c2 and c3 are constants and determined from the experimental results in empty bed (ranz, 1952) 32 12 re cc e psh c sc= + (18) equation 18 for mass transfer in empty bed was fitted for air flow through fluidized bed, by assuming the limiting value of sherwood number, at zero reynolds number, is equal to 2 because it agrees with the theoretical approach. the experimental results were correlated by using statistical fitting, as shown below: 1/ 2 1/32 0.657 ree psh sc= + (19) with correlation coefficient of 0.9907 and percentage of average errors of 0.62%. for experiments that carried out at minimum fluidizing velocity, the value of the dimensionless group, y, is inconsistent with other experiments due to the term (g-gmf) which is equal to zero at minimum fluidizing velocity, so results obtained at minimum fluidization are neglected. the term f(y) in equation 17 is chosen as a power function of y , that is: 2 1( ) c f y c y= (20) two attempts have been made to correlate the experimental results: 1. the first attempt was made by choosing the dimensionless function, y, as given by ziegler (ziegler and holmes, 1966), i.e.: 2 1 2 ( ) [ ] ( ) ( ) cmf e p p g g sh sh c d g µ ψ ρ ρ ρ − = + − (21) eq. 21 was fitted for air flow through fluidized bed using the experimental results at minimum fluidization velocity, and was correlated by the following equation: 014.0 2 6.9                                 − − += g pp d mf gg eshsh ρρρψ µ (22) with the correlation coefficient of 0.976 and percentage of average errors of 1.57%. fig. 7 shows a comparison of eq. 22 with the experimental data. it can be seen from this figure, that the correlation suggested by ziegler and holmes don’t fit the experimental results of this work. 2. the second attempt was made by taking the dimensionless group, y , as obtained from the dimensionless analysis, i.e.: 32 1 2 ( ) ( ) ( )( ) [ ] [ ] ( ) ccp p p mf e mf g d d g g sh sh c g g ρ ρ ρ ψ ψ µ − − = + − (23) eq. 23 was fitted using statistical fitting for the experimental results of air flow through fluidized bed at minimum fluidization velocity, the constants of the equation c1, c2 and c3 have been found to be equal to 16.8574, 0.07497 and 0.1284 respectively. with the correlation coefficient of 0.914 and percentage of average errors of 1.544 %. fig. 8 shows comparison of eq. 51 with the experimental data. from this al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 figure it can be notice that this correlation shows a better agreement with experiments, in which 97% of the points have an error less than 25%, consequently this correlation obtained from the present work. comparison of experimental results with previous works and model solid mass capacity has an essential affect on surface-to-fluidized bed mass transfer. for (cms=0) low mass transfer coefficients are attained and there is no similarity with surface-to-bed heat exchange. in the case of non-zero solid mass capacity, mass transfer coefficients are greater and for small values of (cms) they may be predicted from the theory proposed by yokota (yokota, 1975). for relatively large values of ( psmsdc τ/ 2 ) greater than 10-5 m2/s the contact resistance is dominant and the surface-to-packet mass transfer coefficient is inversely proportional to (ds). for small values of psmsdc τ/ 2 less than 10-10 m2/s the packet resistance predominates and the surface-to-packet mass transfer coefficient is independent of particle size as represented in table 6. fig. 9 show a comparison between the experimental results of mass transfer and those obtained from documented experimental literatures data; this comparison are represented in yokota,s coordinate. for very large mass capacities, sherwood numbers predicted from yokota,s theory considerably overestimate experimental ones, so there must be an additional mass transfer resistance. it is apparent that this resistance depends on particle size and rises as (ds) increases, which agrees with the contact resistance concept and don’t show any appreciable (ds) dependence. studying the variables affecting mass transfer coefficient: many variables effect mass transfer have been investigated such as: air velocity, sphere surface temperature, size of fluidizing particles and sphere size. the range of sphere surface temperature varied from ambient temperature to a temperature below the melting point of naphthalene. figs. 10 and 11 show the effect of air temperature on sherwood number, fig. 12 shows the effect of air flow rate on sherwood number, figs. 13, 14 and 15 show the effects of both air temperature and particle size on sherwood number, the effects of both air flow rate and particle size on sherwood number are showed in figs. 16, 17 and 18 the effects of both particle size and different temperature on sherwood number are showed in figs. 19, 20, 21 and 22. conclusions: in this work, a mathematical model for mass transfer was introduced depends on one dimensionless group which results from the merge of the two dimensionless groups derived in this work and was fitted for air flow through fluidized bed using the experimental results at minimum fluidization velocity. the mathematical model had successfully describes the effects of different parameters on the mass transfer coefficient such as air velocity, sphere surface temperature, size of fluidizing particles and sphere size, when compared with the experimental results and gives a good improvement rather than ziegler equation. sherwood number increased slowly with the increase in gas velocity at constant surface temperature and particle size, although it is increasing with decreasing surface temperature of the sphere at constant u/umf and particle size, and sherwood number increased with decreasing particle size at constant u/umf and temperature. the ratio of sherwood number for mass transfer in the presence of solid particles (fluidized bed) to that in absence of solid particles (empty bed) was found to be varied up to 30. references: al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 1. baeyens j. and geldart d., 1974, "an investigation into slugging fluidized beds", chem. eng. sci. vol. 29, pp. 255. 2. baskakov a. p. and suprun v. m., 1970, “mass transfer from a freely moving single sphere to the dense phase of a gas fluidized bed of inert particles”. sov. chem. ind. vol. 9, pp. 61. 3. baskakov a. p., 1974, “critique of the modified packet theory”. journal of engineering physics and thermophysics, vol. 28, no. 5, pp. 584-586. 4. baskakov a. p., b.v. berg, o.k. vitt, n.f. filippovsky, v.a. kirakosyan, j.m. goldobin and v.k. maskaev, (1973), “heat transfer to objects immersed in fluidized beds”. powder technology, vol. 8, pp. 273-282. 5. baskakov, a. p. and suprun v. m., 1972, "the determination of the convective component of the coefficient of heat transfers to a gas in a 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(5th edition). mcgraw hill, new york, ny. 18. prins w., casteleijn t. p., draijer w. and. van swaaij w. p. m, 1985,” mass transfer from a freely moving single sphere to the dense phase of a gas fluidized bed of inert particles”. chem. eng. sci., vol. 40, no. 3, pp. 481-497 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 19. prozorov e. n., 1976, “kinetics of the removal of liquid from capillary porous bodies in a fluidized bed under nonisothermal conditions”. izuest. vuz-ov khim. technol., vol. 30, no. 6, pp. 1127–1137. 20. ranz w. e. and marshall w. r., 1952, "evaporation from drops". chem. eng. prog. vol. 48, pp. 141-173. 21. resnick w. and white r. r., 1949, “mass transfer in systems of gas and fluidized solids”. chem. eng. prog. vol. 45, pp. 377. 22. rhode, m.j., wang x.s., nguyen m., stewart p., and liffman k. (2001),"use of discrete element method simulation in studying fluidization characteristic: influence of antiparticle force", chemical engineering science, vol. 56. p. 69. 23. schmidt a., renz u., 2005, “numerical prediction of heat transfer between a bubbling fluidized bed and an immersed tube bundle”, heat-mass transfer, vol. 41, pp. 257–270. 24. shirai, t., yoshitome, h. and shoji y., 1966, “heat and mass transfer on the surface of solid spheres fixed within fluidized”. kagaku kogaku, vol. 4, pp. 880 – 884 25. wankhede u. s., 2009, “effect of increase in surface temperature on heat transfer in a sound assisted fluidized bed of fine powders”. international journal of engineering studies, vol. 1, no. 1, pp. 31–38. 26. wen y.c. and yu y.h., 1966, “mechanics of fluidization”, chemical engineering progress symposium series, vol. 62, pp. 100-111. 27. yokota t., hidaka y. and yasutomi t., 1975, “mass transfere”, kagaku kogaku ronbunshu, vol.1, p. 399. 28. ziegler, e. n. and holmes j. t., 1966,” mass transfer from fixed surfaces to gas fluidized beds”. chem. eng. sci., vol. 21, pp. 117-118. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 205 table 1: property of sand particles particle density (kg/ m3) range particle size (micron) range of particle size (micron) 2600 112.5 75-150 2600 165 150-180 2600 215 180-250 table 2: operational conditions for experiment of mass transfer in empty bed without naphthalene test 1 for sphere of diameter 2.9 cm and weight 8 gm, air flow rate 2.8 m3/hr, ambient temperature 39 0c, pressure drop 0.9 cm h2o test 2 for sphere of diameter 2.9 cm and weight 8 gm, air flow rate 2.8 m3/hr, ambient temperature 39.1 0c, pressure drop 0.9 cm h2o test 3 for sphere of diameter 2.9 cm and weight 8 gm, air flow rate 3.7 m3/hr, ambient temperature 39.1 0c, pressure drop 1.4 cm h2o time (min) wt. loss (gm) t2(℃) t1(℃) wt.(gm) wt. loss (gm) t2(℃) t1(℃) wt.(gm) wt. loss(gm) t2(℃) t1(℃) wt.(gm) 0 39.0 39.0 10.21 51.3 51.3 10.2 66.0 66.0 12.45 5 0.087 39.1 39.1 10.12 0.2884 51.1 51.2 9.93 1.0717 66.1 66.2 11.38 10 0.079 39.1 39.0 10.04 0.2514 51.3 51.4 9.68 1.0215 66.1 66.2 10.36 15 0.072 39.0 39.0 9.968 0.3102 51.3 51.4 9.37 0.7172 66.1 66.0 9.637 20 0.083 39.0 39.1 9.884 0.1913 51.2 51.2 9.17 0.6251 66.0 66.1 9.013 25 0.079 39.0 39.0 9.805 0.1241 51.1 51.3 9.05 0.6765 66.1 66.0 8.337 note: t1 = temperature below the sphere, t2 = temperature above the sphere. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 table 3: operational conditions for experiment of mass transfer in fluidized bed without naphthalene tests test 1 for sphere of diameter 2.9 cm and weight 8 gm, air flow rate 4 m3/hr, ambient temperature 390c, pressure drop 21 cm h2o test 2 for sphere of diameter 2.9 cm and weight 8 gm, air flow rate 4.8 m3/hr, ambient temperature 39.30c, pressure drop 23 cm h2o test 3 for sphere of diameter 2.9 cm and weight 8 gm, air flow rate 5.2 m3/hr, ambient temperature 39.40c, pressure drop 25 cm h2o time (min) wt. loss(gm) t2(℃) t1(℃) wt.(gm) wt. loss(gm) t2(℃) t1(℃) wt.(gm) wt. loss(gm) t2(℃) t1(℃) wt.(gm) 0 39.1 39.1 12.74 51.2 51.2 12.35 66.1 66.2 15.56 5 0.1147 39.0 39.1 12.63 0.45317 51.0 51.0 11.89 1.5197 66.1 66.1 14.04 10 0.1954 39.0 39.0 12.43 0.48788 51.1 51.2 11.40 1.4178 66.0 66.1 12.63 15 0.1721 39.1 39.2 12.26 0.39927 51.1 51.1 11.01 1.5503 66.1 66.0 11.07 20 0.1229 39.1 39.0 12.13 0.47188 51.0 51.1 10.53 1.2799 66.1 66.3 9.795 25 0.1627 39.2 39.2 11.97 0.5561 51.1 51.0 9.98 1.6998 66.0 66.0 8.095 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 205 table 4: operational conditions and results for mass transfer in empty bed she rep weight loss (gm/hr.m 2) temp 0c air flow rate(m3/hr) tests no. 17.3135 285.1003 16.0007 39.0 2.8 1 18.7098 345.8269 17.4398 39.1 3.4 2 19.3947 377.7627 18.3160 39.2 3.7 3 19.9931 406.7856 18.4545 39.0 4.0 4 21.0113 458.6925 19.6208 39.1 4.5 5 22.3181 529.8438 20.6403 39.0 5.2 6 17.1085 277.7204 46.3716 51.3 2.8 7 16.9799 272.8329 65.2329 55.3 2.8 8 16.8026 266.4974 148.507 66.1 2.8 9 18.4820 336.7652 49.6271 51.2 3.4 10 18.3388 330.7357 68.0483 55.2 3.4 11 18.1415 323.0021 160.042 66.1 3.4 12 19.1685 368.4121 51.7253 51.2 3.7 13 19.0308 362.3935 71.6804 55.3 3.7 14 18.7530 350.6095 163.612 66.0 3.7 15 19.7436 396.0089 52.5007 51.1 4.0 16 19.5742 388.2574 73.0415 55.3 4.0 17 19.3535 378.8475 171.623 66.2 4.0 18 20.7647 447.5064 56.4473 51.3 4.5 19 20.6113 440.0929 77.5178 55.3 4.5 20 20.2874 424.9063 179.185 66.2 4.5 21 22.0536 516.9524 59.3788 51.2 5.2 22 21.8811 507.9866 82.1496 55.3 5.2 23 21.5112 489.2557 189.438 66.2 5.2 24 *air flow rate measured at ambient temperature. table 5: experimental conditions for mass transfer in fluidized bed sand mean particle size (micron) exp. no. air flow rate (m3/hr) u/umf temp. 0c wt. loss (gm /hr .m2) rep she 215 1 4.0 1.081 39.1 30.550 943.71 254.612 2 4.4 1.189 39.1 31.754 964.75 258.791 3 4.8 1.297 39.2 33.483 972.29 262.413 4 5.2 1.405 39.2 34.911 982.71 269.751 5 4.0 1.081 51.0 84.836 951.64 214.622 6 4.4 1.189 51.0 89.614 967.90 225.704 7 4.8 1.297 51.2 94.233 971.53 243.950 8 5.2 1.405 51.3 98.408 979.46 257.568 ٩ 4.0 1.081 55.2 121.607 916.60 203.815 10 4.4 1.189 55.1 124.457 945.03 217.780 11 4.8 1.297 55.2 130.413 969.87 247.502 12 5.2 1.405 55.0 132.781 972.37 227.235 13 4.0 1.081 66.3 285.096 884.27 172.751 14 4.4 1.189 66.1 295.131 989.40 194.224 15 4.8 1.297 66.0 297.444 944.85 203.705 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 16 5.2 1.405 66.3 313.011 961.19 214.443 165 1 3.0 1.071 39.0 25.509 661.73 281.599 2 3.4 1.214 39.0 27.221 753.69 305.431 3 3.8 1.714 39.2 29.075 839.76 334.890 4 4.0 1.428 39.1 29.756 889.36 344.508 5 3.0 1.071 51.1 73.244 648.80 264.114 6 3.4 1.214 51.3 78.891 734.67 283.170 7 3.8 1.714 51.0 81.180 822.97 295.800 8 4.0 1.428 51.1 84.641 871.43 307.709 9 3.0 1.071 55.0 100.240 640.28 247.105 10 3.4 1.214 55.1 107.812 728.69 265.401 11 3.8 1.714 55.3 115.400 814.63 281.715 12 4.0 1.428 55.2 117.142 857.09 299.552 13 3.0 1.071 66.0 240.074 629.50 227.746 14 3.4 1.214 66.1 256.227 713.26 239.534 15 3.8 1.714 66.2 270.089 782.94 252.753 16 4.0 1.428 66.3 280.120 827.04 274.766 112.5 1 2.4 1.091 39.0 23.162 524.39 349.553 2 2.8 1.272 39.1 25.077 611.68 364.710 3 3.0 1.363 39.2 25.833 650.19 377.455 4 3.2 1.454 39.0 26.042 692.23 389.107 5 2.4 1.091 51.1 64.938 505.76 327.114 6 2.8 1.272 51.2 70.487 591.29 339.415 7 3.0 1.363 51.3 74.378 639.27 359.770 8 3.2 1.454 51.0 75.018 683.96 378.105 9 2.4 1.091 55.3 91.653 500.88 314.211 10 2.8 1.272 55.2 99.647 593.28 332.154 11 3.0 1.363 55.1 100.780 630.22 351.005 12 3.2 1.454 55.0 103.917 676.43 368.417 13 2.4 1.091 66.0 212.427 489.99 305.215 14 2.8 1.272 66.1 230.876 573.56 319.419 15 3.0 1.363 66.3 682.796 930.62 335.498 16 3.2 1.454 66.2 698.345 992.66 357.794 table 6: comparison of the orders of magnitude of the experimental parameters silica gel-air-water (rmp/rmw ~ 0) sand-air-water (rmp/rmw~∞) sand-air-naphthalene (rmp/rmw~∞) (m2/s) 10-3 10-2 10-2 /m msc c 10 2 102 103 (m2/s) 10-5,10-6 10-11,10-12 10-9,10-10 al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 fig. 1: photographic picture of the experimental equipment 1. rotameter 2. variac 3. heating equipment 4. temperature reader 5. fluidization column 6. manometer fig. 2: experimental setup. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 0.01 0.10 1.00 10.00 velocity (cm/s) 0.01 0.10 1.00 10.00 p b e d ( c m h 2 o ) fig. 3: distributor pressure drop fig. 4: bed pressure drop vs. air velocity (sand particle size = 215 micron) 1.00 air velocity (cm/s) 1.00 10.00 ^ p b e d ( c m h 2 o ) 10.00 p̂ b ed ( c m h 2 o ) 1.00 air velocity (cm/s) fig. 5: bed pressure drop vs. air velocity (sand particle size = 165 micron) fig. 6: bed pressure drop vs. air velocity (sand particle size= 112.5 micron) 100.00 200.00 300.00 400.00 sh (exp. ) 100.00 200.00 300.00 400.00 s h ( c a lc .) all point within solid lines are of error less than 25 % all points within dashed lines are of error less than 15 % 100.00 200.00 300.00 400.00 sh (exp. ) 100.00 200.00 300.00 400.00 s h ( ca lc .) all point within solid lines are of error less than 25 % all points within dashed lines are of error less than 15 % fig. 7: a comparison of eq. 50 with the experimental data fig. 8: a comparison of eq. 51 with the experimental data 1.00 air velocity (cm/s) 10.00 ̂p b e d ( c m h 2 o ) al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 fig. 9: comparison of experimental data with the packet theory systems is follows: silica gel-air-water [(o) ds=0.548mm, ( ∆ ) ds=0.875 mm, (� ) ds=1.342mm]. sand-air-water [(◊) ds=0.496mm].sand-air-naphthalene [(� )ds=0.351mm] (yokota, 1975). sand-air-naphthalene (present work) [(▪) ds=215 micron, (▪) ds=165 micron, (▪) ds= 112.5 micron] 20.00 40.00 60.00 80.00 temperature ( c ) 100.00 200.00 300.00 400.00 s h ( e x p . ) part. size= 215 micron part. size=165 micron part. size=112.5 micron 0.00 20.00 40.00 60.00 80.00 temperature( c ) 100.00 200.00 300.00 400.00 s h ( ex p .) part.size = 215 micron part. size = 165 micron part.size = 112.5 micron fig. 10: experimental sh. vs. temperature at air flow rate = 1.2 umf fig. 11: experimental sh. vs. temperature at air flow rate = 1.4 umf al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 0.00 0.40 0.80 1.20 1.60 2.00 flow (u / umf) 100.00 200.00 300.00 400.00 s h ( e xp . ) part. size=215 micron part. size=165 micron part. size =112.5 micron temperature = (51.0 _ 51.2) c 20.00 30.00 40.00 50.00 60.00 70.00 temperature ( c ) 100.00 150.00 200.00 250.00 300.00 s h ( c a lc .) 1.2 umf 1.4 umf 1.3 umf particle size = 215 micron fig. 12: experimental sh. vs. air flow rate fig. 13: effect of temperature on calculated sh. no 20.00 30.00 40.00 50.00 60.00 70.00 temperature ( c ) 100.00 200.00 300.00 400.00 s h ( ca lc .) particle size = 165 micron 1.2 umf 1.4 umf 1.3 umf 20.00 30.00 40.00 50.00 60.00 70.00 temperature ( c ) 280.00 320.00 360.00 400.00 s h ( c al c .) particle size = 112.5 micron 1.2 umf 1.4 umf 1.3 umf fig. 14: effect of temperature on calculated sh no. fig. 15: effect of temperature on calculated sh. no. 1.00 1.20 1.40 flow (u/umf) 100.00 150.00 200.00 250.00 300.00 s h ( ca lc .) 39 c 51 c 55 c 66 c part. size = 215 micron 1.20 1.60 2.00 flow (u/umf) 100.00 150.00 200.00 250.00 300.00 350.00 s h ( c al c .) 39 c 51 c 55 c 66 c part. size = 165 micron fig. 16: effect of air flow rate on calculated sh. no. fig. 17: effect of air flow rate on calculated sh. no. al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 0.80 1.20 1.60 2.00 flow (u/umf) 100.00 200.00 300.00 400.00 s h ( c al c .) 39 c 51 c 55 c 66 c part. size =112.5 micron 120.00 160.00 200.00 240.00 particle size (micron) 100.00 200.00 300.00 400.00 s h ( c a lc .) 1.2 umf 1.4 umf 1.3 umf temperature = 39 c fig. 18: effect of air flow rate on calculated sh. no. fig. 19: effect of sand particle size on calculated sh. no 100.00 150.00 200.00 250.00 particle size (micron) 100.00 200.00 300.00 400.00 s h ( ca lc .) 1.2 umf 1.4 umf 1.3 umf temperature = 51 c 120.00 160.00 200.00 240.00 particale size (micron) 100.00 200.00 300.00 400.00 s h ( c al c. ) temperature = 55 c 1.2 umf 1.4 umf 1.3 umf fig. 20: effect of sand particle size on calculated sh. no. fig. 21: effect of sand particle size on calculated sh. no al-qadisiya journal for engineering sciences vol. 3 no. 2 year 2010 212 120.00 160.00 200.00 240.00 particale size (micron) 100.00 200.00 300.00 400.00 s h ( ca lc .) temperature = 66 c 1.2 umf 1.4 umf 1.3 umf fig. 22: effect of sand particle size on calculated sh. no. effect of liquid properties on heat transfer coefficient in gas-liquid bubble column al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 effect of physical properties on heat transfer and flow regimes in bubble columns dr.balasim a. abid nada mahdi farhan dr. shurooq talib al-hemeri university of technology university of technology university of technology baghdad , iraq baghdad , iraq baghdad , iraq e-mail: dew82ars@yahoo.com e-mail: salhemeri2004@yahoo.com received 11 may 2014 accepted 25 march 2015 abstract this work discusses the effect of superficial gas velocity and liquid properties (viscosity µ, surface tension σ, thermal conductivity k , density ρ , specific heat cp ) on the heat transfer coefficient and gas holdup investigated in a bubble column. experiments were carried out in a plexiglass column (0.15 m diameter and 1.5 m height). a perforated plate was used as a gas distributor, having 84 holes of 1mm diameter, and 0.37% opening area. the heat transfer coefficient was measured for the air-liquid systems in bubble column of four types of liquid (water, 60%ethanol, 35% glycerol, and 65% glycerol) covering a range of surface tension and viscosity values, while the gas phase is atmospheric air. the superficial gas velocity, ug, was varied in rang of (0.0037-0.094) m/sec. for all sets of experiments the height of liquid phase was maintained constant at 0.8 m above the gas distributor. from experimental, data it is found that the values heat transfer coefficient for aqueous glycerol solutions decrease with increasing concentration of glycerin and are lower than those for 60%ethanol and water solutions. this is attributed to the combined effects of surface tension, viscosity, specific heat, and thermal conductivity of the liquid. the overall gas holdup for all liquids increases with an increase in superficial gas velocity, the liquid property has an impact on gas holdup. an increase in liquid viscosity results in large bubbles and thus higher bubble rising velocities and lower gas holdup. a correlation based on dimensionless groups for the prediction of heat transfer coefficient is proposed and found to be in good agreement with available data. keywords: heat transfer coefficient; liquid properties; bubble column. keywords: heat transfer coefficient; liquid properties; bubble column; gas hold up; superficial gas velocity. تأثير الخواص الفيزيائية على انتقال الحرارة وانظمة التدفق في االعمدة الفقاعية د.شروق طالب الحميري ندى مهدي فرحان د.بالسم احمد عبد الجامعة التكنولوجية الجامعة التكنولوجية الجامعة التكنولوجية العراق -بغداد العراق -بغداد العراق -بغداد e-mail: dew82ars@yahoo.com e-mail: salhemeri2004@yahoo.com الخالصة , ρ, الموصلية الحرارية, الكثافة σ, الشد السطحي μيناقش هذا البحث تأثير سرعة الغاز السطحية وخواص السائل ) اللزوجة ( على معامل انتقال الحرارة وتعطيل الغاز )الغاز المحتجز( في العمود الفقاعي.التجارب نفذت في عمود рсالسعة الحراريه ملم .فتحة كل منها بقطر 48م( والموزع الغازي عبارة عن صفيحة مثقبة تتكون من 0..م(وارتفاعه ) 0..5زجاجي قطره ) سائل في العمود الفقاعي ألربع أنواع من السوائل -المساحة المفتوحة. تم قياس معامل انتقال الحرارة لألنظمة غاز 0..5ونسبة mailto:dew82ars@yahoo.com mailto:dew82ars@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 اللزوجة والشد السطحي,بينما المرحلة الغازية %كليسيرول( حيث تم تغطية مدى من 00%كليسيرول, 0.%ايثانول, 05)ماء, (م/ثانية. في جميع التجارب يكون ارتفاع السائل 5.5.8-5.55.0تتغير من ) ɢuتتمثل بالهواء الجوي. سرعة الغاز السطحية ة تركيز م فوق موزع الغاز. ولقد وجد من خالل التجارب ان معامل انتقال الحرارة لمحاليل الكليسيرين يقل بزياد5.4ثابت %ايثانول والماء. ويعزى ذلك الى التأثير المشترك لكل من الشد 05الكليسيرين وهو اقل من معامل انتقال الحرارة في محاليل السطحي, اللزوجة, السعة الحرارية والتوصيل الحراري للسائل.تعطيل الغاز ) الغاز المحتجز( الكلي لجميع السوائل يزداد بزيادة ية.خواص السائل له تأثير على تعطيل الغاز )الغاز المحتجز( حيث ان الزيادة في لزوجة السائل تؤدي الى سرعة الغاز السطح تكوين فقاعات غازية كبيرة والتي تكون ذات سرعة عالية وبالتالي فأن تعطيل الغاز )الغاز المحتجز( يقل. ولقد تم استنتاج معادلة تفق بصورة جيدة مع البيانات العملية المتوفرة.عملية لحساب معامل انتقال الحرارة والتي ت nomenclature a heat transfer area m 2 cp specific heat j/kg.k d diameter of the column m g gravitational acceleration m/s 2 hw heat transfer coefficient kw/m 2 .k h liquid height of the column m i electric current a k thermal conductivity w/m.k q heat flow rate kw t temperature 0 c tb bed temperature 0 c tl liquid temperature 0 c tref reference temperature 0 c ts surface temperature 0 c ug superficial gas velocity m/s v voltage v greek µ dynamic viscosity pa.s ρ density of water kg/m 3 σ surface tension j/m 2 εg overall gas holdup -- introduction the bubble column is regarded as one of the most important multiphase flow systems. it is widely used in many industrial applications including chemical, biochemical, petrochemical, environmental and metallurgical processes, balasim et al. [1]. examples of such chemical and petrochemical processes are partial oxidation of ethylene to acetaldehyde, wet-air oxidation, methanol synthesis, and hydrogenation of organic liquids. in biochemical industries bubble columns are used for cultivation of bacteria, cultivation of mold fungi and treatment of sewage. in metallurgical industries, it can be used for leaching of ores, rahman [2]. the industrial importance of bubble columns remains undisputed mainly due to the advantages that it offers from absence of moving parts, leading to easier maintenance, simple construction, high effective interfacial area, the continuous phase is well mixed, a relatively low pressure drop, good temperature control, excellent heat rate caused by strong gas-liquid interactions, and reasonable inter-phase mass transfer rates at low energy input required for operation, anil [3]. design and scale-up of bubble columns remain challenging tasks due to the complexity of their non-linear hydrodynamics and phases interactions, rahman et al. [4]. thermal control in bubble columns is of importance since in many chemical and biochemical processes, chemical reactions are usually accompanied by heat supply (endothermic) or removal (exothermic) operation. therefore, maintaining desirable bulk media temperature is necessary which plays an important role in the performance of the reactor ,nigar et al. [5]. consequently such reactors are equipped with heat exchangers immersed in the main reactor to control the heat of reaction. reactor walls al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 may also be employed for this purpose, khalid [6]. the knowledge and understanding of heat transfer phenomena in bubble columns and quantifying the heat transfer rates and coefficients are important since they are required for proper, safe and efficient design and operation of these reactors, rahman et al. [4]. as mentioned earlier, one attractive feature and main characteristics for the wide applications of bcs is the high heat transfer rate, where the heat transfer rate in gasliquid flow of bubble columns is reported to be 100 times greater than in single phase (gas phase) flow for the same flow rates with respect to column cross section, rahman [2]. high heat transfer rate is one of the important characteristics in the operation of bubble column. this rate is influenced by a number of physical parameters and operating conditions. gas-holdup , superficial gas velocity, circulation velocity and physical properties of liquid, all these factors are highly interactive and control the bubble column performance, khalid [6]. bubble columns are used in a variety of processes as an apparatus to achieve mass transfer and/or chemical reaction, usually in low viscosity system. in the last two decades, bubble columns have found widespread application in biotechnological processes such as the production of baker's yeast, wastewater treatment, single-cell protein production, and citric acid fermentation etc. of the high viscosity systems, khalid [6]. experimental investigations on bubble columns are performed with pure water and few for liquids more viscous than water. there is a lack of knowledge about the effect of liquid properties on the heat transfer process and thus, on gas holdup in bubble columns. the purpose of this work is to study the effect of liquid properties on heat transfer coefficient in a bubble column. various liquids covering a range of surface tension and viscosity values are employed, while atmospheric air is used as the gas phase for all experiments. a new correlation is proposed for the prediction of heat transfer coefficient. experimental section experiments were conducted in a large-scale grid of plexi glass column of 0.15 m internal diameter and height 1.5 m as shown in figure (1). the top of the column is opened to the atmosphere. the column was supported by rigid metallic structure to keep it vertical and to minimize the mechanical vibrations which might affect the measured heat transfer signals. oil-free compressed air constituted the gas phase, while (tap water, 60% ethanol, 35% glycerol, 65% glycerol) were used as the liquids phase, table (1) gives the liquid phase used in this work together with their physical properties. the experiments were conducted in a semi-batch mode; continuous in relation to the gas flow and batch with reference to the liquid flow. gas flow was supplied by compressor; the flow rate of air was adjusted by rotameters system, consisting of two rotameters connected in parallel to increase gas velocity range. the superficial gas velocity was varied in the range of (0.0019 to 0.094) m/s which cover both bubbly and churn-turbulent flow regimes. air was introduced into the column through a perforated stainless-steel plate of 3 mm thickness which had 84 holes, with a diameter of 1 mm and 0.37% opening area, a conical shape reducer was installed for the purpose of minimizing the fluctuation of the gas phase. heat was supplied to the gas-liquid dispersion in the bubble column from the electrically heated heat transfer section. the heater assembly is shown in figure (2), which was installed vertically at 0.3 m above the distributor as a heat source in the immersed heater-to-bed system with 0.012 m diameter by 0.5 m length, 1000 w/ 220v electric heating u shaped elements. the power consumed by the heater was controlled by means of variac transformer to give 577.5 w for different surface heater and bulk temperatures. a clamp meter was used also to measure the power directly for more accurate results. five thermocouple sensors of k-type were used to sense the temperature in bubble column, two thermocouples at the heat transfer surface element were used to measure the surface temperature of the heating element (ts), three thermocouples are used to measure the temperature in the bed at different height in bubble column, and the average bed temperature is (tb). all thermocouples are al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 connected to the data acquisition system (interface) which can be defined as an electronic circuit which enables the communication between the system under study and the computer to take advantage of the computer software for generating reports, plots, etc …. a temperature measuring interface unit was built to measure the temperature from five type (k) thermocouples, the interface was connected to the computer and can be calibrated and controlled via visual basic 6.0 application software written especially for this purpose, the measured temperature from each sensor was exported to a text file plus the measuring time for further analysis. the interface scanning rate was fixed to be 1 second between each sensor reading, so that, each sensor would be scanned every 8 second. a type k transducer was connected inside the unit case for each thermocouple, each transducer was calibrated by an equivalent electronic circuit inside it to the reference point at 0°c, and the output for each transducer was designed according to the following equation [7]. )(0.1 ref ttv  (1) where voutput in mv and the temperature was measured in °c, tref. was fixed to be 0°c, v was designed to be 0.1 mv for each 1 °c difference. at 0°c, the transducer output would be 0 mv. hence, at 100°c the transducer output voltage is equal to 100 mv. the transducer signal was then converted to a digital signal using an analog – to – digital converter and transferred directly to the computer via the printer port. any deviation from the designed output voltage can be handled by the program. this can be achieved by immersing all thermocouples in a steady – state constant bath temperature and monitor the deviation in order to sense the deviation which normally should be in the order of  3°c. the heat transfer coefficient hw was calculated by dividing the heat rate by the heating surface area and the temperature difference between the heating surface and bulk liquid temperatures, assuming quasi-steady-state condition [8]. (2) results and discussion in this study, the heat transfer coefficients in air-water, air-60% ethanol, air-35% glycerol and air65% glycerol systems were investigated 1. effect of superficial gas velocity 1-1 effect of superficial gas velocity on heat transfer coefficient the effects of superficial gas velocity were investigated for different air-liquid systems. figures 3 (a, b, c and d) show the heat transfer in air-water, air-60% ethanol, air-35% glycerine, and air-65% glycerine versus superficial gas velocity. it can be seen that the strong influence of the superficial gas velocity on the heat transfer coefficient for all air-liquid system between the bubbly and churn-turbulent flow regimes. heat transfer coefficients increase with an increase of gas velocity, irrespective liquid viscosity. these results also showed that the rate of increase of heat transfer coefficients with gas velocity was rapid at low gas velocity (bubbly flow regime), this must be related to the fact that at low superficial gas velocity the small bubble sizes are formed and almost uniformly distributed throughout the whole column area, the bubbles rise almost vertically with the same speed and without coalescence drifting an amount of liquid to the top of the column ,by further increasing in the gas flow rates the increase in heat transfer coefficient become smaller with in the churn al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 turbulent flow regime this related to that when the superficial gas velocity increased continued the significant gas transport occurs through the large bubbles formed by coalescence begin to rise resulting in a kind of churn-turbulent flow pattern which cause slow down in heat transfer coefficient. this is in agreement with the observations of ( rahman [2], nigar et al. [5], khalid [6],ola [12], hanning [13] ). figure (4) from chen et al. [16] depicts approximate flow structure observed with increasing gas flow. the dispersed bubble flow regime (i) is characterized by nearly uniform bubble size and radially uniform gas holdup. this is followed by transition regime (ii) when increasing gas velocity generates more bubbles leading to increased bubbles interactions and growth in bubble size. the larger bubble stream is seen moving through column center where the heat transfer rate is expected to increase. with further increase in gas velocity, coalesced bubble flow (or heterogeneous) regime (iii) is reached where fast moving large coalesced bubbles begin to emerge due to combined effect of higher initial bubble size and faster coalescence rate, anil [3]. 1-2 effect of superficial gas velocity on gas holdup gas holdup (εg ) is one of the most important parameters in bubble columns; it is basically defined as the reactor dynamic volume occupied by the gas or the volume fraction of gas phase occupied by the gas bubbles, likewise it is possible to characterize the liquid phase holdup as the volume fraction of liquid,( rahman [2], khalid [6], maedeh and faramarz [17],and behnoosh et al. [18] ). the direct visual observation for the measurements of the total gas holdup; is determined from the knowledge of slumped liquid-phase column height (hs) when the gas flow through the liquid is zero (static height), and the expanded height or dynamic height (he) of the two-phase gas liquid suspension corresponding to a particular value of the superficial gas velocity (ug), and the following relation, rahman [2]: e se g h hh   (3) gas hold up depends mainly on the superficial gas velocity. in this study the gas hold up have been measured at different superficial gas velocity, the results are shown in figure (5). all the experiences show the positive effect of superficial gas velocity on gas hold up. this positive effect has been shown in the most published studies, (rahman [2], nigar et al. [5], khalid [6], hanning[15], maedeh and faramarz [17],behnoosh et al. [18] ,and boris [19] ). the gas holdup would increase linearly with the gas flow rate (superficial gas velocity). in the homogeneous regime (bubbly flow regimes), the bubble size is small and uniform and bubble travel upwards in a helical path without any major collision or coalescence, as the gas flow rat increases the hindrance progressively reduces the bubble velocity leading to a further increase of the gas holdup. the opposite holds true for the heterogeneous regime, at high superficial gas velocity all the bubbles will be large. the large bubbles have higher rise velocity than small bubbles, therefore residence time of large bubbles decrease and cause to decrease rate of increasing gas hold up. 2. effect of liquid properties 2-1 effect of liquid properties on gas holdup the liquid phase property has an impact on bubble formation and/or coalescing tendencies and hence is an important factor affecting gas holdup, nigar et al. [5]. the liquid properties which are most important are the surface tension and the viscosity of the medium, heijnen and riet [20]. figure (6) the data are plotted in terms of gas holdup versus gas phase superficial velocity for air– al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 60% ethanol, air–water, air–35% glycerine and air–65% glycerine systems. as it is expected, gas holdup increases with gas flow rate. as shown in figure (6) a slight increase in gas holdup values is observed when the lower surface tension ethanol solution is used as liquid phase. compared to water, the surface tension is the only physical property which differs significantly from water. the effect of surface tension on gas holdup can be qualitatively described in that a lower surface tension gives a lower bubble rise velocity and therefore a higher holdup, heijnen and riet [20]. it is also evident from figure (6) that the influence of ethanol is bigger for high air flow rates. in these conditions, collision between air bubbles is more intense and bubbles coalescence becomes increasingly significant, the surface tension being a major influence on this process. at low air flow rates, the liquid-phase surface tension has little effect on gas holdup. the amount of air into the reactor is small and the coalescence is not significant. so, the inhibition of coalescence by ethanol is not high enough to be relevant, carla and jose [21]. also gas holdup is very dependant on the viscosity of liquid, auroba[22]. figure (6) refers to strong influence of glycerine concentration on the gas holdup. thus, as the concentration of glycerine solution was increased, the mean gas holdup value decreased in the bubble column, or in other words. it was found that the gas hold up value decreases with increasing liquid viscosity. therefore, the decrease in gas holdup values may be attributed to: increasing of the system viscosity and formation of large bubbles with fast rising velocity, khalid [6] . 2-2 effect of liquid properties on heat transfer coefficient the physical properties of any liquid used in a bubble column will be determined its hydrodynamic behavior and then the rate of heat and mass transfer. lewis et al. [23] pointed to the importance of the distinguishing between the low viscosity and high viscosity systems, because of the hydrodynamic behavior is not the same. therefore, the liquid viscosity, surface tension and liquid density in the end determine the extent of liquid circulation and then the amount of heat transfer rate, (hikita et al.[24]. the effects of liquid properties were investigated for different air-liquid systems. figures (7) show the heat transfer coefficient in air-water, air-60% ethanol, air-35% glycerine, and air-65% glycerine versus superficial gas velocity. the heat transfer coefficient hw for water, 60% ethanol, 35% glycerine and 65% glycerine are shown in figure (7). as can be seen in this figure, the heat transfer coefficient for 60% ethanol lower than those for water, these results may be attributed to the combined effect of surface tension, specific heat and thermal conductivity of the liquids (water, 60% ethanol) when the rest of properties is approximate the same. this mine heat transfer coefficient rises with an increase in heat capacity, and thermal conductivity of the liquid, chengtian [25]. the heat transfer coefficient also increses with increases surface tension, this may be attributing to the decrease of the liquid surface tension, reduce the bubble coalescence rate but increase the bubble breakup rate, which causes the reduction of the bubble size. furthermore, the decrease in bubble size obviously decreases the heat transfer coefficient. the effect of density and viscosity can be neglected. figure (7) also presents the heat transfer coefficient values obtained for 35% glycerine and 65% glycerine. it can be seen that in the figure at the same superficial gas velocity, the heat transfer coefficient decrease with increasing concentration of glycerine solution. on the other hand, the heat transfer coefficients for all highly viscous liquid of glycerine solutions are considerably lower than that for air-water system under the same operating conditions. this may be explained on the basis of the effect of increasing liquid viscosity of the liquids when the effected of the rest of properties is approximate the same and can be neglected. heat transfer coefficient decreases with increasing liquid viscosity in multiphase reactors. the decrease in heat transfer rate has been attributed to increase in thermal boundary sub-layer thickness of laminar flow around the heating surface with al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 177 increasing viscosity due to decrease in turbulence and increase in viscous friction loss between the phases thus increasing resistance for conduction heat transfer anil [3]. 3correlation as described above, the conceivable factors affecting heat transfer coefficient hw are considered to be the superficial gas velocity ug, the liquid specific heat cp, the liquid thermal conductivity k, the liquid density ρ, the liquid viscosity μ, the liquid surface tension σ, and the gravitational constant g. for the present problem the gas properties were not taken into account in obtaining the general correlation. the dimensional analysis and the least-square method were applied to all the experimental data. the final correlation for the heat transfer coefficient hw is given by: 334.0 3 4655.0 451.5 3 2                             gu k c uc h gp gp w (4) figure (8) shows the comparison of the observed and calculated values of the stanton number hw/ρcpug. in this figure, the stanton numbers observed in the present work are plotted against the stanton numbers calculated from eq. (4). the observed stanton numbers are in good agreement with the calculated ones with an average deviation for (water, 60% ethanol, 35% glycerine, 65% glycerine) are (0.73%, 2.8%, 1.4%, 0.9%) and a maximum deviation (2.8%, 9.2%, 2.2%, 1.6% ) respectively if the effect of liquid surface tension on the heat transfer coefficient hw value is ignored, we finally obtain the following correlation: 277.0 3 294.0 3 2                  g u k c uc h gp gp w    (5) figure (9) compares the measured values of the stanton number with those calculated from equation (5). although the measured values of the stanton number are in agreement with the calculated ones with an average deviation for (water, 60% ethanol, 35% glycerine, 65% glycerine) are (2.8%, 4.6%, 0.5 %, 3.9%) and a maximum deviation (11.2%, 11.7%, 1.21%, 12.7% ) respectively, the data points show the systematic error for the data of a few specified systems and display somewhat greater scattering than shown in figure (9), indicating that the effect of the liquid surface tension on the hw value cannot be denied figure (10) shows the comparison of the heat transfer coefficient by experimental work with published correlation predictions,(hart [26]; nishikawa and hashimoto[27]; deckwer [28]; hikita et al. [24]; kawase and moo-young [29]; verma [30]; kawase and kumagai [31]; and yang et al. [32] ). the measured values of the stanton number are in agreement with the calculated ones with an average deviation (5.5%, 4.6%, 5.57%, 3.21%, 5.86%, 5.15%, 5.6%, 6.23%) and a maximum deviation (20.8%, 20.3%, 20.6%, 14.4%, 21.5%, 19.4%, 20.9%, 21.8% ) respectively. therefore the results have shown a good agreement between the experimental measurements and hikita et al.[27] correlation for heat transfer coefficients. however, the measured of other investigations are shown in figure (10) varies from those obtained in this work. this would be attributed to many uncertainties caused by different measurement techniques (probe) used, different operating and design conditions applied in these reported studies and different liquid properties between this work and previous investigations which effect on the hydrodynamic behavior of liquid. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 conclusion the heat transfer coefficient measurements are obtained in different air-liquid systems of a two phase bubble column based on constant heat flux, over a wide range of liquid properties and superficial gas velocities. it can generally be concluded that the heat transfer coefficients increas with an increase in the superficial gas velocity, the increase is rapid in the beginning (bubbly flow regime), but slows as the superficial gas velocity is increased (churn-turbulent flow regime). the heat transfer coefficient for 60% ethanol lower than those for water. these results may be attributed to the combined effect of surface tension, specific heat and thermal conductivity of the liquids (water, 60% ethanol) when the rest of properties is approximate the same. this mine heat transfer coefficient rises with an increase in heat capacity, and thermal conductivity of the liquid. the heat transfer coefficient also increases with increases surface tension, this may be attributing to the decrease of the liquid surface tension, reduce the bubble coalescence rate but increase the bubble breakup rate, which causes the reduction of the bubble size. furthermore, the decrease in bubble size obviously decreases the heat transfer coefficient. the heat transfer coefficient for 35% glycerol and 65% glycerol decrease with increasing concentration of glycerin solution. on the other hand, the heat transfer coefficients for all highly viscous liquid of glycerine solutions are considerably lower than that for air-water system under the same operating conditions. this may be explained on the basis of the effect of increasing liquid viscosity of the liquids when the effected of the rest of properties is approximate the same and can be neglected. heat transfer coefficient decreases with increasing liquid viscosity in multiphase reactors. references [1] balasim, a. , rahman, sh. and hisham, m. t., 2009, " heat transfer behavior in a two-phase bubble column", al-qadisiya journal for engineering sciences ,2 (2), pp.425-438. [2] rahman, s. a., 2008,"heat transfer in bubble column operating in churn-turbulent flow regime" ,ph.d. thesis, university of technology. [3] anil, k. j. , 2001, " effects of internals configurations on heat transfer and hydrodynamics in bubble columns –with and without solid particles" ,ph.d. thesis, university of western ontario. [4] rahman, s., balasim, a.and muthanna, h. ,2011,"heat transfer study in a pilot-plant scale bubble column", chemical engineering research and design, 8(9) , pp.78–84. [5] nigar, k., fahir, b., kutlu, o., 2005," bubble column reactors", process biochemistry 40 , pp. 2263–2283. [6] khalid, a. s., 2004, "heat convection and performance in bubble column" ph.d. thesis, university of technology. [7] haider, a. a., 2006,"heat transfer in gas solid fluidized bed using large particles" m.sc. thesis, university of technology. [8] holman, j.p., 1976, "heat transfer "”, 4th ed. ; mcgraw-hill. [9] celsius process equipment manufacturer for industry "physical data of thermal fluids", http://www.celsius-process.com/_en/pdf/ethanol%2060.pdf. http://www.celsius-process.com/_en/pdf/ethanol%2060.pdf al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 171 [10] gonzalo, v., estrella, a., and jose, m., 1995, "surface tension of alcohol + water from 20 to 50 ºc", j. chem. eng. data, 40, pp. 611-614. [11] coker, a. k., 2010 "ludwig's applied process design for chemical and petrochemical plants",appendix c physical properties of liquids and gases, v( 2), 4 th ed , pp. 757-792. [12] glycerine producers association, 1963, "physical properties of glycerine and its solutions", 1 edition, http://www.aciscience.org/docs/physical_properties_of_glycerine_and_its_solutions.pdf. [13] don, w.and perry, r. 2008 "perry's chemical engineer's handbook", 8th ed. ; mcgraw-hill; pp. 2-183. [14] ola, i. n., 2010, "heat transfer in bubble columns using two different column diameter", msc thesis, chemical engineering, university of technology. [15] hanning, l., 1998, " heat transfer and hydrodynamics in a three-phase slurry bubble column " ph.d. thesis, university of western ontario. [16] chen, r.c., reese, j., fan, l.s., 1994. flow structure in a three-dimensional bubble column and three-phase fluidized bed. aiche journal. 40, 1093-1104. [17] maedeh, a. and faramarz, h., 2013,"effects of surfactant on bubble size distribution and gas hold-up in a bubble column", american journal of chemical engineering, 1( 2), pp. 50-58. [18] behnoosh, m., ensieh, g. b.and jafar, s. m.,2009, "experimental study of gas hold-up and bubble behavior in gas –liquid bubble column", petroleum & coal 51 (1),pp. 27-32. [19] boris, v. a., mirjana, s. d., dragan, l.j. and miodrag, n. t.,2006, "prediction of gas holdup for alcohol solutions in a draft tube bubble column", apteff, 37, pp. 1-192 . [20] heijnen, j.j. and riet ,k. v. , 1984,"mass transfer, mixing and heat transfer phenomena in low viscosity bubble column reactors", the chemical engineering journal ,28 , b21-b42 [21] carla, f. and jose, a. t.,1998,” effect of liquid-phase surface tension on hydrodynamics of a three-phase airlift reactor with an enlarged degassing zone”, bioprocess eng. 19 ,pp. 451-457 [22] auroba, n. a., 2007, " characteristics of bubbles and gas holdup in a two-phase column for different liquid phases", eng. & technology, 25(2), pp.282-290. [23] lewis, d.a., field, r.w., xavier, a.m. and edwards, d., 1982 "heat transfer in bubble columns", trans. inst. chem. eng., vol. 60, p-40. [24] hikita, h., asai, s., kikukawa, h., zaike, t., and ohue, m., 1981, “heat transfer coefficient in bubble columns”, ind. eng. chem. process des. dev., 20, pp.540-545. [25] chengtian, w. , 2007, “ heat transfer and bubble dynamics in slurry bubble columns for fischer-tropsch clean alternative energy”, ph.d. thesis, washington university . http://www.aciscience.org/docs/physical_properties_of_glycerine_and_its_solutions.pdf al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 111 [26] hart, w. f., 1976, “heat transfer in bubble-agitated systems: a general correlation”, ind. eng. chem. process des. dev., 15,pp. 109-114. [27] nishikawa, m., kato, h., and hashimoto, k., 1977, “heat transfer in aerated tower filled with non-newtonian liquids”, ind. eng. chem. proc. des. dev., 16, pp.133-137. [28] deckwer, w. d., 1980, “on the mechanism of heat transfer in bubble column reactors”, chem. eng. sci., 35,pp. 1341-1346. [29] kawase, y., and moo-young, m., 1987, “heat transfer in bubble column reactors with newtonian and non-newtonian fluids”, chem. eng. res. des., 65,pp.121-130. [30] verma, a., 1989, “heat transfer mechanism in bubble columns” the chem. eng. j., 42,pp. 205-208. [31] kawase, y., and kumagai, t., 1991, “heat transfer in bubble column and airlift bioreactors: newtonian and non-newtonian fermentation broths”, j. chem. tech. biotechnology, 51, pp.323-334. [32] yang, g., luo, x., and fan, l., 2000," heat transfer characteristics in slurry bubble columns at elevated pressures and temperatures " ind. eng. chem. res., 39,pp. 2568-2577. table (1): physical properties of liquids used, (celsius[9] , gonzalo et al. [10], coker[11] ,glycerine[12], don.and perry [13] ) liquid tl, ºc µ ˣ 10 3 , pa s ρ ˣ 10 -3 kg/m 3 cp ˣ 10 -3 j/kg k k, w/m k σ ˣ 10 3 j/m 2 60 wt% ethanol 20 1.079 [9] 0.862 [9] 3.059 [9] 0.213 [9] 26.72 [10] 30 0.876 [9] 0.854 [9] 3.159 [9] 0.210 [9] 25.81 [10] 40 0.722 [9] 0.846 [9] 3.258 [9] 0.207 [9] 24.97 [10] 50 0.604 [9] 0.838 [9] 3.357 [9] 0.204 [9] 24.11 [10] water 20 1.029 [11] 1.032 [11] 4.204 [11] 0.599 [11] 74.60 [11] 30 0.817 [11] 1.023 [11] 4.191 [11] 0.613 [11] 72.58 [11] 40 0.665 [11] 1.013 [11] 4.181 [11] 0.625 [11] 70.57 [11] 50 0.553 [11] 1.004 [11] 4.175 [11] 0.635 [11] 68.55 [11] 60 0.468 [11] 0.994 [11] 4.171 [11] 0.645 [11] 66.53 [11] 70 0.403 [11] 0.985 [11] 4.172 [11] 0.654 [11] 64.50 [11] 35 wt% glycerol 20 3.122 [12] 1.086 [12] 3.645 [13] 0.464 [12] 69.89 [12] 30 2.303 [12] 1.081 [12] 3.623 [13] 0.477 [12] 68.65 [12] 40 1.771 [12] 1.076 [12] 3.602 [13] 0.485 [12] 67.36 [12] 50 1.394 [12] 1.058 [12] 3.581 [13] 0.494 [12] 66.06 [12] 60 1.131 [12] 1.052 [12] 3.558 [13] 0.502 [12] 64.70 [12] 70 0.955 [12] 1.047 [12] 3.528 [13] 0.510 [12] 63.23 [12] 65 wt% glycerol 20 15.73 [12] 1.168 [12] 3.115 [13] 0.362 [12] 67.17 [12] 30 10.16 [12] 1.162 [12] 3.103 [13] 0.367 [12] 66.28 [12] 40 6.999 [12] 1.156 [12] 3.090 [13] 0.371 [12] 65.36 [12] 50 5.021 [12] 1.151 [12] 3.077 [13] 0.371 [12] 64.35 [12] 60 3.752 [12] 1.144 [12] 3.064 [13] 0.375 [12] 63.30 [12] 70 2.978 [12] 1.138 [12] 3.052 [13] 0.379 [12] 62.14 [12] al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 111 10 11 14 13 figure (1): schematic diagram of the experimental apparatus heater 9 compressor 1 graduated ruler 10 pressure gauge 2 thermocouples 11 air rotameters 3 variac 12 valve 4 computer 13 needle valve 5 interface 14 non-retarn valve 6 15cm diameter column 15 conical section 7 gas distributor 8 figure (2): schematic diagram of the heater al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 111 a b c d figure (3): effect of superficial gas velocity on heat transfer coefficient for a) water b) 60%ethanol, c) 35%glycerol, c) 65%glycerol figure (4): flow regimes in 3-d bubble column (chen et al.[14]). 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 0 0.02 0.04 0.06 0.08 0.1 ug(m /s) h w ( w /m 2 .k ) air-w ater 0 2000 4000 6000 8000 10000 12000 14000 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) h w ( w /m 2 .k ) air-60%ethanol 0 2000 4000 6000 8000 10000 12000 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) h w ( w /m 2 .k ) air-35%glycerol 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) h w ( w /m 2 .k ) air-65%glycerol i ii iii al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 111 a b c d figure (5): shows the dependence of gas holdup on corresponding gas superficial velocity for air– 60%ethanol, air–water, air–35% glycerol and air–65% glycerol systems . figure (6): shows the effect of liquid properties on gas holdup for air–60%ethanol, air– water, air–35% glycerol and air–65% glycerol systems . 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) ε g air-60%ethanol 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.02 0.04 0.06 0.08 0.1 ug(m /s) ε g air-w ater 0 0.05 0.1 0.15 0.2 0.25 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) ε g air-35%glycerol 0 0.05 0.1 0.15 0.2 0.25 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) ε g air-65%glycerol 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) ε g air-60%ethanol air-water air-35%glycerol air-65%glycerol al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 111 figure (7): shows the effect of liquid properties on heat transfer coefficient for air–water, air– 60%ethanol, air–35% glycerol and air–65% glycerol systems . figure (8): shows the comparison of the observed and calculated values of the stanton number hw/ρcpug. 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 0 0.02 0.04 0.06 0.08 0.1 ug(m/s) h w ( w /m 2 .k ) water 60%ethanol 35%glycerol 65%glycerol 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 hw (w /m 2.k)cal h w (w /m 2 .k )o b s w ater 60%ethanol 35%glycerol 65%glycerol al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 111 figure (9): shows the comparison of the observed and calculated values of the stanton number hw/ρcpug. figure (10): shows the comparison of the heat transfer coefficient by experimental work with published correlation predictions 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 hw (w /m 2.k)cal h w (w /m 2 .k )o b s w ater 60%ethanol 35%glycerol 65%glycerol 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 (hw/ρcpug)cal (h w /ρ c p u g ) o b s hart et al.,1976 nishikawa et al (1977) deckwer (1980) haruo hikita (1981) kawase and moo-young, 1987 verma.,1989 kawase and kumagai, 1991 yang et al., (2000) 1-المقدمة: 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 1 تطوير طريقة نكلست للتشفير المتماثل للمقاطع النصية بشكل القطري المتدرج داخل السلسلة المشفرة suhad abbas yassir nahla flih hassani technical institute, shattra assistant programmer suhadabbass@yahoo.com nahla_hassani@yahoo.com م.م سهاد عباس ياسر م.مبرمج نهلة فليح حساني كلية التربية األساس المعهد التقني/ الشطرة جامعة سومر هيئة التعليم التقني 2024آذار 27ُقبل 2020تشرين االول 00ُأستلم الملخص تعددهذهدددطرذقة من دددرذ دددقذقة دددمتذقةت لنهندددرذلمتنفدددرذةلت دددهاذقةعل دددمذ دددمذ فددد ذقة ددد ذ نددد ذتعت دددهذ لددد ذ دددل ذ كذ لنرذقةتشدفنمذقة لد ذ دمذ(ذقة تخهاذ نقذقة م ذلقة تلاذةفkeyقة عذقة شفمذل ل ذ فت حذقةتشفنم) ال ت هذ ل ذ فت حذقةتشفنمذقةدط ذقةمص،ذ ن ذتتاذ لنرذقمقءةذقةمصذقة شفمذ شك ذأ مذهقخ ذقة لفل رذ مذ ثم ذقة ةمذتاذت لنمذهطرذقة من رذلفعله ذأكثدمذتع ندهقذ دقذذنعت هذمف هذةفكذقةشفمةذ قذق ذقة تلاذ,ذأ ذنفبذأقذنكلقذ ن ذ دككثمذ دقذ من درذقلذل دنلرذن دتخه ه ذقة د ذقةطذقف ذقة ظرذ ل ذقةمصذقة شفم ندد ذتدداذة دد رذذ عددرذقةلددنخذمن ددنرذلخددمق ذقةددمصذقة شددفمذةكددمذتددتاذ لنددرذقةتشددفنمذ شددك ذأكثددمذ لنددرذذ قةدددط ذنعت دددهذ لددد ذقةععقدددرذ دددنقذأ دددهةذللدددفل ذذ دددمذ لدددفل رذكدددطةكذتدددتاذقدددمقءةذقة دددمل ذقة لفدددلهةذهقخددد ذ ت دد هقذ لدد ذقةمه نددرذقة دد رذ لدد ذقةخلقمت نددرذةكددمذتددتاذقمقءتهدد ذ شددك ذق ددم ذذ تددهم ذقة لددفل رذ شددك ذأخددمذق ةل ددددمذقةم ن ددددمذألالذذثدددداذقة ددددمل ذقة لفددددلهةذ ددددلتذقة ددددمذقةم ن ددددمذلأخنددددمقذقة ددددمل ذقة لفددددلهةذأ ددددف ذقة ددددمذ .قةم ن م develop a way nklst symmetric encryption for text clips in diameter gradient inside the encrypted string abstract the aim of this paper is find anew scheme for text encryption. this process depending an reading the cipher horizontally within the matrix which depends on the relationship between the mailto:suhadabbass@yahoo.com mailto:suhadabbass@yahoo.com mailto:nahla_hassani@yahoo.com 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 2 columns & rows in the matrix & the end which added to the algorithm to be read diagonally graded diameter. ذ المقدمة:-2 ذقلذم لهدد ذذ ندد ذالذن كددقذقمقءتهدد ذقالذ ددقذق دد ذقة م دد ذقة ه ددرقة علل دد ذذقخفدد ءذ لنددق ددهذقةتشددفنمذهددلذذذذ .قة تخه ر منرذقة علل ذةة فظذقذق هذأملقعذلتعت مذلقة تلا ذةد ت دع ذقذن تخهاذ متذ تمل درذ شك ذ ت مذ ن ذقةتمذتكخطذ عذقةت لنمقةعللاذ قذذقةتشفنملنعت مذذذذ قةتددمذذقة ددلبذ ددمذ لددالت ددلمذقة لدد ذةذمتنفددرلذ ددمنرذةل علل دد ذذقة م ددلرذ ددمذقمددلق ذقالتلدد ذقة ختلفددر.ذ ت دلنمذذ متذ نرذقة علل ذ قذ منتذ ختلفرذة قذفلهةذقةع ذقة مفتذق هه ذقة ذةنف هذل ذنهه أمظ ددرذ علل د ذه ندر.ذ فددمذذ ددمذقة فد ظذ لد ذقة علل دد ذ دقذخدع ذ ع ةدرتكدلقذةقةتشددفنمذ دمذ لداذت مند ذقة قةفنددهنلذلقةلددلمذقةعهنددهذ ددقذل دد ذقالتلدد ذ ثدد ذقةع ددلهذقةثعثددرذقةخنددمةذقددده ذ ددهةذ ددمتذتشددفنمذةكددمذت ددمذ خده ذقلم د ذ تعدههةذقةل د ذكقةمق نر.ذأمه ذ فنهةذفهقذ مذت هناذأغمقرذ منرذخ لرذ مذت ن ذ ن رذ (rabinovich,vlad 2004)لكطةكذقةللمذقةع كمنر...قةخ.ذذلقة ؤت مق ذقةفنهنلنرذقة لكنرذلقةع لكنر دددمتذتشدددفنمذتتم دددبذ دددعذ فددداذذ لددد ذ لدددلةهاهدددلذذن دددع ذقةنهددد ذ عظددداذقة ددد ثلقل دددقذقةهدددهق ذقةتدددمذذذذ قلذت ددلنمذقة ددمتذقةتددمذ تدد ذ عمل ددرذقلذ ددهلرذقة علل دد ذقة م ددلرذ ددقذف مددبذل ددقذقةف مددبذقةخددمذق ددتخهقاذ ذذ.ذ مذ فظذقة علل ذقة ه رذر ن ذتكلقذأكثمذ لنذقال تخهقا ذ دددقذقة دددمنرذ ددد ةمذ دددمنعرذل دددتل قةذللدددل ذقة علل ددد ت ندددتذقةذقةتشدددفنمذهدددلقغلدددبذ دددمق ذذلنعدددهذهددده ذذذ دقذقفد ذ د قذذ قذقةمصذل ختلد ذقة دمتذذقةكلمذقلذقةفت مذلق هةذ قذهطرذقة مق ذذهلذتشفنمذ,ذلقة قذ ذ.alan, g, 2007 )).قة ف ظذ ل ذ تل ذقة علل ذقة م لرذ ذ :النصوصتشفير -2 هدمذ دقذ ندرذقة علل د ذ دقذ مندتذت لنلهد ذةةد ذم دلتذ عنمدرذغندمذذcryptographyت منرذقةتشدفنمذذذذ الذن كددقذ لهدد ذةالذ ددقذخددع ذ فتدد حذ ددم ذن ددلاذ فددكذطةددكذذcyphertext ددملءةذتدده ذقةملددلصذقة شددفمةذ قةددددط ذ تددددهذقالتلدددد ال ذقلةكتملمنددددرذذقةتشددددفنمذلت لنلددددهذةةدددد ذمددددصذ دددد ه ذ ددددملء،ذلمظددددمق ذةعمتشدددد مذقةك نددددم لخللل ذقلمتمم ،ذ هذغهقذقة قذقلةكتملممذ قذأ خقذقة ن ذقةتمذنمكتذ لنه ذقةعد ةاذ كف عده،ذلت دتخهاذ ت منددرذقةتشددفنمذ ددمذهددطقذقة فدد ذة نددرذقةم دد ذقلةكتملمنددرذلقة علل دد ذقة ه ددرذقة م لةددرذةةكتملمندد ذك ة ن مدد ذ ذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذiyengar,venugopal.2003) ). الخاصة ت د قذلقة ن مد ذقة تعل درذ قد ذقال لقةهه ذ قذقةتشفنمذهلذ قذ فظذقةخلللدن ذل دهاذقة د حذة دهذ ةع د ذ هد ذألذقال دععذ لنهد ذلطةدكذ كلمهدد ذة دد ذ ددمنرذألذخ لددرذفددهق ،ذلالذن كددقذة ددهذأقذنفهدداذ دد لقذتلددكذقة علل دد ذألذقةم دد ذةالذ ددقذةهنددهذ 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 3 أ ذة هةذقة ن م ذةةد ذذdecryptionقة فت حذقة م ذقةخ صذ ه ذلقةط ذتتاذ قذ من هذ لنرذ كذقةتشفنمذ ذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذ..ذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذلنغته ذقةللنرذكمصذ د ه ق ددتخهقاذ عددرذقةتعلن دد ذقة ددمنرذقةتددمذنشدد مذةةنهدد ذ دد هةذذلتت لددبذكدد ذ ددقذ لنتددمذقةتشددفنمذل ددكذقةتشددفنمذذذ ف تنحذخ لر.ذلت تخهاذ عرذت من ذقةتشفنمذقة فت حذمف هذ مذقةع لنتنقذ مذ نقذتختل ذتلكذقة ف تنحذ دقذ (ذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذpeeter laud,varmo vene 2005)ذذ. لندددددددددرذةخددددددددددم ذ دددددددددمذت مندددددددددد ذأخدددددددددم ذذ.ذذذذذذذذذذ.ذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذ. لةكدددقذت منددد ذقةتشدددفنمذقةندددلاذأ دددهذ كثندددمذلأكثدددمذت دددلمق ذ دددقذ فدددمهذقةتشدددفنمذل دددكذقةتشدددفنم،ذل دددمذقةلققدددعذأقذذذذ لللنر،ذ ك ذ ل لعذأل ةرذلل رذقة ن م ذلقة علل ذالذن ذأه نرذ ةم رذةة ذقةف نعذ قذ ل لعذقةخ م لاذ مذ ن تم ذقةنل نرذ ةتلقنعذ ثع ذ ل ذ تمهذ ذألذقة لاذ لندهذةلهالةدرذ لد ذأمدهذلد نحذ بممد ذ فدرذ دمذ قة ذةة ذمظ اذن قذقةشمءذطقتدهذلةكدقذ من درذةةكتملمندر،ذك د ذنشد ذ ل دلعذقةتشدفنمذأ دلمق ذأخدم ذكثندمةذ . هةذتتنحذة ك منرذقةه عذ تخهقاذقة د ذقلةكتملمدم قذخع ذأهلق ذ عنمرذن كقذ م ءذ مق ذلأمظ رذ ع (qi, hairong,2002) التشفير المتماثل: 2-2 ددقذقة لق ددنعذقةتددمذنعمدد ذ هدد ذقةكثنددمذ ددقذقة دد ثنقذ ددقذقفدد ذذ دد ةم ددمذقةلقدد ذقةقةتشددفنمذقالهت دد اذ علدداذذنعدهذذذ نكدلقذنشدك ذ تك د ذ دقذف ندعذت د ذلأقذذ ةشدك ذقةدط ذنكدلقذا مد ذل د لم ذذت نقذقةمللصذقلذقة علل ل دقذتلدكذقةت مند ذهم ةدكذ"،ذل مذقةلق ذطقتهذ بقذةلتشفنمذأملقعذكثندمةذلت مند ذ ختلفدر،ذأغمق ه ك رذلذذفلقم ه قةتدمذنعت دهذ نهد ذكد ذ دقذقة م د ذلقة م د ذذقةعل ندرلهدمذ دقذقةت مند ذذsecret keyت مندرذقة فتد حذقة دم ذ ندد ذن ددلاذقةل ذ ددتخهقاذطةددكذقة فتدد حذةتشددفنمذقةم دد ةرذ ن دد ذن ددتخه هذقةثدد ممذةفددكذةةنددهذقة فتدد حذقة ددم ذطقتدده،ذ ."ذsymmetric cryptographyطةكذقةتشفنمذلقمقءته،ذلتعم ذهطرذقة من رذ اذقةتشفنمذقة ت ث ذ (papamarkos,2000)قةشددخصذقة ددمقهذذةةد لققذ ثد ذهددطرذقة مندتذقةتددمذت ده ذ لنددرذللدل ذقة علل دد ذذ قةد ذقةشدخصذقة عمدمذلهدمذت دتذ ت ل د ذقةع د ذقةمد فحذ دنقذكددعذذذلأ د قهدطرذقةملدلصذ دمنرذ ثد ذذةم د نقذقةمصذت ذل قذقف ذ قذخع ذ عم رذقةشفمةذقةخ لرذ ةخلقمت نرذقة تخه رذ مذت نتذقةتشفنم.ذقة م نقذ ذ(1ك ذ مذشك ذ)ذ.k = [k1, k2, ..., kj] لالمف تذتكلنقذقة فت حذx = [x1, x2, .... xm]قةلمنحذقةط ذنتكلقذ :نكلستطريقة -2-2 (ذقة ددتخهاذ ددنقذkey فتدد حذقةتشددفنم) ددل ذقة ددعذقة شددفمذلكددطةكذ لدد ذ ددل ذتعت ددهذهددطرذقة من ددرذ لدد ذذذذ ةفكذ لنرذقةتشفنمذقة ل ذ مذقةمص،ذل مذمفسذقةلق ذققذقة عذقة شدفمذنفدبذققذنكدلقذذقة م ذلقة تلا ذ دد ذةهدد ذ ددههذقةفمقغدد ذقة ددم نكددلقذةهدد ذ ددههقذتلفندد ذ ددقذذقةتددمذ ددههذ ددقذقة ددم نددهذقةددمصذقة ددتخهاذ قةتمذتكلقذ ل رذ عذ ههذقة م ذقة مقهذتشدفنمه ذ،ذأ د ذ دمذ ةدرذأطقذكد قذ دههذقة دم ذقة دمقهذتشدفنمه ذ دمذ ذذ ههقذتلفمذقة عذ شك ذ مه ذن ذةة ذهطرذقة هقهذ مقغذلق هذةكمذنل حذقةعههذقةكلمذةل عذقة شفم 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 4 k قة شدفم قةدمص تلةنده أفد دقذkل دل ذقة فتد حذذ xلقمت ندرذ لد ذ دل ذقةدمصذقةلدمنحذ ند ذتعت دهذقةخ قةتمذن كقذكت ته ذ ل ذقةم لذقةتد ةمذذy = [y1, y2 ...., yn] ذقةلمنح قةمص تخهقا قةخلقمت نر ت لا x لقة فت ح y = ek (x)ذ ذ[ذ.k,x ذك ذ قذ] ال ت هذ لذe قذخع ذقةخلقمت نرذذ yل عم ذقخمذن كقذق تمت ذ خوارزمية التشفير : -3 ةت ن دهذتذ دعذ نعدرذذقةهده ذقةدط ذن دع ذ تفد دقذخدع ذقالم دف اذلقالةع ذك ذ ذذقة نرققذقةغ نرذذذذ ل مذقغلبذ لن ذقةتمذن تمهذ لنه ذك ذقة ثلقذهمذقة هئذقلذقة لق هذقة نرذةهطقذقةع ذةطذقتفهذ ذ ذةت لنمذق هذقة متذقةتشفنم.قة ثت قذ مذهطقذقة ذ ذ.ذn. بذ ل ذقةمصذقة للبذتشفنمرذلفعلهذ ة تغنمذ1 ذ.ذj. بذ ل ذ فت حذقةتشفنمذلفعلهذ ة تغنمذ2 ذ.ذi=n/j ن ذأقذذi.ذقنف هذقن رذقة تغنمذ3 نددد ذنكدددلقذذa(i,j).ذت ندددعذقةدددمصذقة لدددلبذتشدددفنمرذلخدددتقذكددد ذ دددم ذ مدددهذ لقدددعذ دددقذ لققدددعذقة لدددفل رذ4 ذ ذ د)قةل ذقةل ذلقةع لهذقةل ذ(ذلقة م ذقةث ممذ د)قةل ذقةل ذلقةع لهذقةث ممذ(ذ....لهكطقذ.قة م ذقةلذ ذ.ذa(i,j)قة ذأقذنتاذقهخ ذك ذ مل ذقةمصذ ة لفل رذذ4.تع هذقةخ لةذمقاذ5 ذةندتاذ عدهذطةدكذaةن ثد ذمقداذقةع دلهذ ة لدفل رذذk.ذت نعذ فت حذقةتشفنمذلقخطذأل ذمقاذ مدهذلفعلدهذ د ة تغنمذ6 لفعلهدد ذ دد ةع لهذقةل ذ ددقذ لددفل رذقةتشددفنمذذa( i,k) ددقذقة لددفل رذذkأخددطذقة ددمل ذقة لفددلهةذ دد ةع لهذمقدداذ b(i,j)ن ذأقذذ d=a(i,k)ذذ,b(i,j)=dذ.ذ تد ذندتاذقدمقءةذأخدمذمقداذ دقذأمقد اذ فتد حذقةتشدفنمذةندتاذ دقذخعةدهذقهخد ذاخدمذ دلهذذ6.ذتكمقمذقةخ لةذمقاذ7 ذ.ذb قذأ هةذ لفل رذقةتشفنمذ ندد ذنددتاذذb(i,j) ددقذخددع ذقددمقءةذقة ددمل ذقة لفددلهةذ ة لددفل رذذs.ذقخددمق ذقةددمصذقة شددفمذلختمددهذ دد ة تغنمذ8 ثدداذأخددطذقة ددم ذقةثدد ممذ ددقذ)قةلدد ذذsأخددطذقة ددم ذقةل ذ ددقذ)قةلدد ذقةل ذ,قةع ددلهذقةل (ذلفعلددهذ دد ة تغنمذ ذ...ذلهكطق.ذsقةل ذ,ذقةع لهذقةث ممذ(ذلق تهذقة ذ تلن ذقة تغنمذ ذb( i,j) تدد ذنددتاذقالمتهدد ءذ ددقذأخددطذ ددمل ذقةلدد ذقةخنددمذ ددقذ لددفل رذقةتشددفنمذذ 8قةخ ددلةذمقدداذذ.ذتعدد ه9 ذ.sلق ته ذقة ذقة تغنم ذ.(ذflow chart 1)ك ذ ل حذ مذذذةن ث ذقةمصذقة شفمذ.ذs. رذقة تغنمذ11 خوارزمية فك الشفرة : 3-1 ذ.ذn. بذ ل ذقةمصذقة شفمذلفعلهذ ة تغنمذ1 ذ.ذj حذقةتشفنمذلفعلهذ ة تغنمذ. بذ ل ذ فت2 ذ.ذi=n/j ن ذأقذذi.ذقنف هذقن رذقة تغنمذ3 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 5 ةنتاذذcةن ث ذمقاذقةع لهذ لفل رذ كذقةتشفنمذذk.ذت نعذ فت حذقةتشفنمذلقخطذأل ذمقاذ مهذلفعلهذ ة تغنمذ4 لفل رذ كذ قذ ذkلفعله ذ ةع لهذمقاذذb(i,j) عهذطةكذأخطذقة مل ذقة لفلهةذ ةع لهذقةل ذ قذقة لفل ر ذ.ذc(x1,k)=dل مهذذذd=b(x1,y1) ن ذأقذذcقةتشفنمذ ت ذنتاذقمقءةذأخمذمقاذ قذأمق اذ فت حذقةتشفنمذةنتاذ قذخعةهذأخطذاخمذ لهذ قذذ4.ذتكمقمذقةخ لةذمقاذ5 ذ.ذc قذقة لفل رذذkلقهخ ةهذ ةع لهذمقاذذbأ هةذقة لفل رذ ن ذذc(i,j)قمقءةذقة مل ذقة لفلهةذ ة لفل رذ قذخع ذذs1.ذقخمق ذقةمصذقةلمنحذذلختمهذ ة تغنمذ6 ثاذأخطذقة م ذقةث ممذ قذذs1نتاذأخطذقة م ذقةل ذ قذ)قةل ذقةل ذ,قةع لهذقةل (ذلفعلهذ ة تغنمذ ذ...ذلهكطق.ذs1)قةل ذقةل ذ,ذقةع لهذقةث ممذ(ذلق تهذقة ذ تلن ذقة تغنمذ ذc( i,j)قةل ذقةخنمذ قذ لفل رذ كذقةتشفنمذذ ت ذنتاذقالمته ءذ قذأخطذ مل ذ 6.ذتع هذقةخ لةذمقاذ7 ذ.s1 لق ته ذقة ذقة تغنم (3ك ذ نقذ مذشك )ذةن ث ذقةمصذقةلمنحذ.ذs1. رذقة تغنمذ8 ذ :)القطرية( الجديدة طريقةال -4 دمذةغدرذذه م فدذ قذقف ذتشفنمه ذ شك ذأكثمذتع نهقذ قذخع ذق دتخهقاذ ل ذقةمللصذذقة من رذت نتتاذذذذ م دد لذذةتشددفنمذ(ن ددك فددل ذ ) قةتددمذفعلدد ذ ددقذقة لددفل رذذقل دد ددقذخددع ذذأكثددمذلأ دد ق ددع رذقةددمصذذق ذتع نهقذ ذك م ذ لنرذذأكثم دههقذتلفند ذذ قةفمقغد ذ عذقةمه مذقةم ت ذكلقققذنذنشتم ل ذقةمصذقة شفمذقةط ذذلن لاذقة مم ذ بذذذ قذنكددلقذ دد قذ لق دد ذقةعددههذقةتلفددمذة ددل ذقةددمصذ ددمقءةذ ددل ذقة فتدد حذقةددط ذنفددبذق ل ددقذثدداذن ددلاذقة ممدد ذذ ذأم عدرنتكدلقذ دقذ(ذ م د ذذ نفدبذققذنكدلقذقة فتد حذقة دتخهاذ11 ثعذنكلقذ ل ذقةمصذقة شفمذ تكلقذ قذ) ذقةم عدرذةهمق ند ذندتاذ م د ذ(ذ11كدلقذ دقذ لق د ذقةعدهه)ت(ذ4)ذ ةمق ا قذ لق ذقةعههذةمصذقة شفمذذأمق ا لقةغمرذ قذطةكذل عذقةمصذقةلمنحذذ(4123 من رذ شلق نرذ ثعذ)عننقذأ ذ شك ذ عثمذالذ ل ذقةتذأمق ا ذ ل ذة ل ذقة فت حذل ههذلفل ه ذ=ذ ل ذقةمصذ ل ذ ل ذ ل ذقة فت حذ.ذأ هته لفل رذ ههذ ك ذ م ذ ك قذذلك ذ نقذذ=a[ذi,j]ذمذ لفل رذ ذل عهذطةكذن لاذقة مم ذ ل عذقةمصذقة شف ذذذذذذذذذذذذذذذذ s u m m ذ ذذذذذذذذذذذذذ e r u ذذذذذذذذذذ[i,jذ]a=ذذذذذذ n i v e ذذذذذذذذ r s t y ذذذذذذذ 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 1 قة هخلدرذةل فتد حذلقةتدمذذقةمقد اقة لدفل رذ ال ت د هذ لد ذ دههذذ هةأ ذة هق من رذقةتشفنمذ قذخع ذذتعت هذذذ قةتدمذذقةم دلذقةتد ةم ل ل =i,j ] b(ذذةكمذنتاذل عذقة لفل رذ شكله ذقة نعمذ]4123)ذذأ عرك م ذ ة ث ذ (ذa(ذ هالذ قذقة لفل رذ)b قذخعةه ذنتاذقمقءةذقةمصذقة شفمذ قذقة لفلةذ) ذذذذذذذذذذ ذذذ m s u mذذذذذذذذ u e r -ذذذذذذ[ذ=i,jذ]bذذذذذذ e n i vذذذذذذذ y r s tذ ذذذذذ ذ key ذت دهن ذأ د كقذقة دمل ذ ة لدفل رذ ال ت د هذ لد ذقةمقد اذقة لفدلهةذ ة فتد حذنتاذقةتشفنمذ دقذخدعذذذ ت دلنمذهدطرذقة من درذلطةدكذ دقذقةتمذتاذق ت هه ذ قذقفد ذذقل رذل مذ ذنخصذن رذمنكل ذ,لهطرذهمذ مذ هةذهددطرذقةلددنخذقةمن ددنرذقة ددتمعت ددهذهددطرذقةلددنخذنخددع ذة دد رذلددنخذمن ددنرذأخددم ذلخددمق ذقةددمصذقة شددفمذ ذ لفل رذقةتشفنمذ.ذهقخ ذذقةععقرذ نقذأ هةذللفل ذذ ل ذ ثاذقة مل ذقة لفلهةذ لتذذألالذل مذقةم ن مهقخ ذقة لفل رذةذل مل ذقة لفلهةقة تهمفرذة ن ذنتاذقمقءةذذذذ .لك ذ ل حذ مذقةخلقمت نر قة مذقةم ن مذلأخنمقذقة مل ذقة لفلهةذأ ف ذقة مذقةم ن م : ةالجديدخوارزمية ال 4-1 ذ.ذn. بذ ل ذقةمصذقة للبذتشفنمرذلفعلهذ ة تغنمذ1 ذ.ذj. بذ ل ذ فت حذقةتشفنمذلفعلهذ ة تغنمذ2 ذ.ذi=n/j ن ذأقذذiقن رذقة تغنمذذةنف ه.ذ3 ن ذنكلقذذa(i,j).ذت نعذقةمصذقة للبذتشفنمرذلختقذك ذ م ذ مهذ لقعذ قذ لققعذقة لفل رذ4 ذهذقةل ذ(ذلقة م ذقةث ممذ د)قةل ذقةل ذلقةع لهذقةث ممذ(ذ....لهكطقذ.قة م ذقةل ذ د)قةل ذقةل ذلقةع لذ ذ.ذa(i,j)ك ذ مل ذقةمصذ ة لفل رذذةهخ أقذنتاذذةة ذ4.تع هذقةخ لةذمقاذ5 ةنتاذ عهذطةكذذaةن ث ذمقاذقةع لهذ ة لفل رذذk.ذت نعذ فت حذقةتشفنمذلقخطذأل ذمقاذ مهذلفعلهذ ة تغنمذ6 لفعله ذ ةع لهذقةل ذ قذ لفل رذقةتشفنمذذa( i,k) قذقة لفل رذذk ةع لهذمقاذأخطذقة مل ذقة لفلهةذ b(i,j)ن ذأقذذ d=a(i,k)ذذ,b(i,j)=dذ.ذ اخمذ لهذذةهخ ت ذنتاذقمقءةذأخمذمقاذ قذأمق اذ فت حذقةتشفنمذةنتاذ قذخعةهذذ6.ذتكمقمذقةخ لةذمقاذ7 ذ.ذb قذأ هةذ لفل رذقةتشفنمذ قذخع ذقمقءةذقة مل ذقة لفلهةذ ة مذقةم ن مذةل لفل رذذsتمهذ ة تغنمذ.ذةخمق ذقةمصذقة شفمذلخ8 b(i,j)ثاذقة مل ذقة لفلهةذ لتذقة مذقةم ن مذثاذقة مل ذقة لفلهةذت ذقة مذقةم ن مذأ ذأمهذ:ذذ ذ 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 7 ذ. (4ك ذ نقذ مذقةشك )ذةن ث ذقةمصذقة شفمذ.ذs. رذقة تغنمذ9 ذ خوارزمية فك الشفرة : 4-2 .ذn ل ذقةمصذقة شفمذلفعلهذ ة تغنمذذ. ب1 ذ.ذj. بذ ل ذ فت حذقةتشفنمذلفعلهذ ة تغنمذ2 ذ.ذi=n/j ن ذأقذذiقن رذقة تغنمذذةنف ه.ذ3 م لمذقة مذقةم ن مذثاذذةهخ ثع ذ مق ذ ن ذنتاذألالذذ b(i,j).ذةهخ ذقةمصذقة شفمذ ة لفل رذ4 ذم ن مذ. م لمذ لتذقةم ن مذلأخنمقذ م لمذت ذقة مذقة ةنتاذذcةن ث ذمقاذقةع لهذ لفل رذ كذقةتشفنمذذk.ذت نعذ فت حذقةتشفنمذلقخطذأل ذمقاذ مهذلفعلهذ ة تغنمذ5 قذ لفل رذ كذذkلفعله ذ ةع لهذمقاذذb(i,j) عهذطةكذأخطذقة مل ذقة لفلهةذ ةع لهذقةل ذ قذقة لفل ر ذ.ذc(x1,k)=dل مهذذذd=b(x1,y1) ن ذأقذذcقةتشفنمذ ت ذنتاذقمقءةذأخمذمقاذ قذأمق اذ فت حذقةتشفنمذةنتاذ قذخعةهذأخطذاخمذ لهذ قذذ4قمذقةخ لةذمقاذ.ذتكمذ6 هخ ةهذbأ هةذقة لفل رذ ذ.ذc قذقة لفل رذذk ةع لهذمقاذذلق ن ذذc(i,j) قذخع ذقمقءةذقة مل ذقة لفلهةذ ة لفل رذذs1قةمصذقةلمنحذذلختمهذ ة تغنمذذةخمق .ذ7 ثاذأخطذقة م ذقةث ممذ قذذs1 قذ)قةل ذقةل ذ,قةع لهذقةل (ذلفعلهذ ة تغنمذذنتاذأخطذقة م ذقةل ذ...ذلهكطق.ذs1 تلن ذقة تغنمذذةة ذلق ته)قةل ذقةل ذ,ذقةع لهذقةث ممذ(ذ ذc( i,j) ت ذنتاذقالمته ءذ قذأخطذ مل ذقةل ذقةخنمذ قذ لفل رذ كذقةتشفنمذذ 6.ذتع هذقةخ لةذمقاذ8 ذ.s1 قة تغنمذةة ذلق ته ذ(5ك ذ نقذ مذشك )ذةن ث ذقةمصذقةلمنحذ.ذs1. رذقة تغنمذ9 االستنتاجات : -5 نددد ذ ذ لندددرذأكثدددمفعهددد ذلذذ من دددرذمكل ددد ذةتشدددفنمقمتدددك ذقة ثتددد قذقة نددد اذ من دددرذ تم دددرذةلت دددلنمذذذذ ذ.هقرذأكثملةت نقذللل ذقة علل ذ شك ذذقختمققه ذقآلخمنقنلعبذ ل ذ ددهةذةألقةخ لددرذذععقدد ذمن ددنرذقة عددرذذة دد رذذهدد ددقذخعةقةتددمذتدداذذذةفهنددهة ددمذ من ددرذقةتشددفنمذقذذذ ذأل ق تمتف ذقة ثت قذققذهطرذقة من رذذ،ذقةتع ذ شك ذق م ذ تهم ذنتاذ لفل رةهقخ ذقللفل ذ قةغنددمذ عمنددنقذ ددكذهددطرذذقآلخددمنق لنددرذ ددقذخددع ذقةتع دد ذ شددك ذق ددم ذ تددهم ذلهددطذنلددعبذ لدد ذذأكثددم قذقةفتددمةذقةت منددرذقةتدمذت ددتخهاذ ددنقذقة م دد ذلقة ددتلاذتكدلقذ شددك ذ شددمذلالذتت لددبذلقدد ذقةشدفمةذ ددعذ دد لككمددهذ لنددرذةم دد ذم دد ذن كددمهاذذقةشددفمةذذ لندد ذةكددمذنت ددم ذةهدداذقةت دد لمذ ن دد ذ نددمهاذ شددك ذ ددمنعذ ددع ذكددطةكذتع دد ذقل دد رذقةفهنددهةذذقلف ددرذ لنهدد ذ ددم رذ لدد ذقةددمغاذ ددقذلفددلهذتشددفنمذهقخدد ذهددطرذقةملددلص. s ( =الرئيسي القطر أسفل الحروف(+)الرئيسي القطر فوق الحروف(+)الرئيسي القطر حروف ) 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 8 دددقذ دددمل ذقة لفدددلهةذ ددد ة مذقةم ن دددمذةلقةفدددتءذقةل ذذ دددمتكدددلنقذمدددصذ شدددفمذنتكدددلقذ دددقذثدددع ذأفدددتقءذ ة لدفل ر,ذقةفدتءذقةثدد ممذقة دمل ذقة لفدلهةذ ددلتذقة دمذقةم ن ددمذلقةفدتءذقةث ةد ذقةعم لددمذقة لفدلهةذت دد ذق . نرذ ذك م ذ لنهذقةتمذتفعله ذأكثمذقة مذقةم ن مذ ذ referances [1] rabinovich, vlad: “steganography–a cryptography layer” . accessed, jan,2004,p80. ]2 [. alan g. , computer security & cryptography , prentice hall : united states of merica, 2007, p 101. [3] iyengar, venugopal,;“hiding messages in images and text:risk associated with the technology of steganography”, isaca infobytes journal, 2003, p98. [4] peeter laud and varmo vene: a type system forc omputationally secure information flow. in maciej liskiewicz and r¨udiger reischuk, editors, fct, volume 3623 of lncs2005, p 365–377. springer,. ]5[ j. daemen and v.rijmen, "the design of rijndael, advanced encryption standard", isbn 3-540-42580-2, springer-verlag,berlin, 2002. [6] n. papamarkos and a. atsalakis: “gray-level reduction using local spatial features”, computer vision and image understanding,2000,p 78 . ]7[geoffrey smith and rafael alpzar: secure information flow with random assignment and encryption. in fmse, 2006, p 33–44. [8] qi, hairong, snyder, wesley e. & sander, william a.: “ blind consistencybased steganography for information hiding in digital media”. multimedia and expo, 2002. icme '02. proceedings. 2002 ieee international conference on vol. 2002, p, 585588. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 9 (daemen ,2002)…. ذ ذ ( نموذج للتشفير المتماثل2شكل ) 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 قة هقنر nعدد حروف النص المطلوب تشفيره)طول النص(= jلتشفير=عدد أرقام مفتاح ا i =n/j i1 =0 i1 =i1+1 j1 =0 j1 =j1+1 t=1 zمن النص المطلوب تشفيره = tحرف بالموقع a(i1,j1)=z if j1< j yes no if i1< i yes no y1=1 i1=1 t =t+1 k(= i1)رقم من مفتاح التشفير بالموقع x1=0 x1=x1+1 d=a(x1,k) b(x1,y1)=d ifx1< i yes no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 ذ ذ ذ ذ ذ ذ ذ ذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذذ ذ لتشفيرل نكلست خوارزميةل ياالنسياب مخططال يوضح) 2شكل) ذ ذ i1=i1+1 y1=y1+1 if i1< j yes no s=0 x3=0 x3=x3+1 y3=0 y3=y3+1 s=s + b(x3,y3) if y3< j yes no if x3< i n0 no طباع النص المشفر sوالكائن بالمتغير قةمه نر 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 12 قة هقنر n)طول النص(=المشفرعدد حروف النص jعدد أرقام مفتاح التشفير= i =n/j i1 =1 y1=1 k(= i1)رقم من مفتاح التشفير بالموقع x1=0 x1=x1+1 d=b(x1,y1) c(x1,k)=d ifx1< i yes no i1=i1+1 y1=y1+1 if i1< j yes n0 s1=0 x3=0 x3=x3+1 y3=0 y3=y3+1 yes 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 13 ك الشفرة( يبن عملية ف0شكل) s1=s1 + c(x3,y3) if y3< j yes no if x3< i no طباع النص الصريح والكائن s1بالمتغير end 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ yes yes yes no no no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 15 ذ ذذ yes yes yes yes yes yes yes no no no no no no no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ يبين الخوارزمية الجديدة :(4شكل) yes yes yes no no no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 17 ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ yes yes yes yes no no no no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 18 ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ yes yes yes yes yes no no no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ عملية فك الشفرة :(5شكل) yes yes yes no no no 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 21 ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذ ذيبين واجهة البرنامج: (6شكل) article al-qadisiyah journal for engineering sciences 12 (2019) 031–037 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author:. e-mail address: zainabd.abbas@uokufa.edu.iq (zainab d abbasl). https://doi.org/10.30772/qjes.v12i1.586 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. application of gis and ahp technologies to support of selecting a suitable site for wastewater sewage plant in al kufa city zainab dekan abbasl a* and osama jassima aenvironmental department, urban planning college,kufa university, iraq. a r t i c l e i n f o article history: received 07 february 2019 received in revised form 11 march 2019 accepted 29 march 2019 keywords: gis spatial information system specifications of sewage treatment modern technologies analytical hierarchy process a b s t r a c t sewage water treatment before disposing of it in surface water is one of the most important steps in reducing pollution in these waters, which requires a high-capacity treatment plant for this purpose. al kufa city is one of the important cities in iraq. the city faced a rapid growth of population. this situation creates big environmental complications and hazards. one of the biggest pollution issues in the city is the lack of modern and efficient waste water treatment plant (wwtp). the aim of this study is to find a suitable site for wastewater plant in al kufa city using remote sensing (rs) and geographical information system (gis) modern technologies. there are eight parameters considered in the analysis consists of residential area, sewage areas, roads, a slope of the ground, surface water (river), green areas, historical, and land use. in addition to that, the analytic hierarchy process (ahp) was used to apply the weights for each criterion and sub-criterion, to get the best result and find the ideal site. at the first place, about thirty-eight sites have been identified as suitable sites for wastewater plant throughout the study area which represented through a red region color in a satellite image with its' coordinate table. the best location will be chosen according to the required land area on which the project is to be built from thirty-eight locations. however, a complementary field study is critical to manifest the obtained results t with specialized engineers to find the most effective site for wwtp between these sites. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the sewage treatment problem is one of the primary issues in many urban communities worldwide and it deteriorated as of late in various districts. in najaf _ iraq, shatt al kufa ( kufa river ) is the major supply of water needed for drinking, irrigation, industry, and other applications. this river shows decreasing quantity and quality of water because of the rapid growth of industrial, agricultural and municipal activities [khassaf, 2017]. this matter makes this river more susceptible to pollution easily. therefore sewage water should dilute from its pollution before throwing it in this river, it through an efficient treatment plant. al-barrakiya station in kufa is working on treating heavy water in all the joints of najaf governorate, which generated very large pressure on that station, which is almost beyond its absorptive capacity figure (1), which necessitates to search for another treatment plant to relieve this pressure. taking advantage of modern gis and remote sensing techniques gis/rs, this study proposes a technique for selecting an optimal site for sewage treatment plant depending on eight criteria. in the recent time, the rs/gis data and geospatial analysis http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 32 zainab d abbasl and osama jassimb /al-qadisiyah journal for engineering sciences 12 (2019) 031–037 fundamentals have been applied to many water and wastewater engineering facilities, particularly in their planning, design, and monitoring before construction and maintenance after construction. the rs/gis applications give a simple way of integrating and analyzing this environmental data for efficient and successful implementation of an environmental project [usman, 2013]. use of gis programming as a decision-making tool permits for arranging of alternatives which meet the required multiple criteria fully. analytic hierarchy process (ahp) is a one of multi-criteria decision making (mcdm) has been applied (for the criteria evaluations) to build an evaluation model and has criterion weights [al maliki, 2017]. in this paper, we merge the ahp with gis approaches to support ideal site choice. numerous environmental studies have shown widespread gis /rs applications for solving this problem such as [zaho, 2015] which shows how can choosing an ideal site for a sewage treatment plant in guangyuan of china in a scientific way by using gis technic. another study was [zaho, 2009] which proved based on gis technology, using eco-suitability evaluation method integrating economic, social and ecological factors to optimize the locations of the sewage treatment plants. and [abdulla and el khidir, 2017] imploded study which clear how can build a decision-making model for selecting the ideal site for a wwtp utilizing the remote sensing and gis data and analysis coupled with the multi criteria analysis (mca) for six criteria in omdurman city sudan. . figure 1. a sewage treatment plant in al kufa city [6] 2. study area in this search (al kufa city) is the study area, as the biggest city in the najaf governorate it is a city in iraq, it lies about 170 kilometers south of baghdad, and 10 kilometers northeast of najaf. it is located on the banks of the euphrates river. the estimated population in 2016 was (31.129.225), geographical coordinates, it located in degrees minutes seconds (wgs84) latitude( 32◦02'05''), longitude (44◦ 24' 12''). the total area is 438.317 km2, approximately. [www.http//alkufa,2018] figure (2, 3). the main hydrological features are the perennial al kufa river represents the main source of agriculture and drinking water. figure 2. located off the study area [5] figure 3. a boundary of the study area [5] 3. materials and methods different information sources have been used during this study, they can be classified into two main sorts as raster and vector information sources, the following data are employed in this study. original data, the obtained map data represent different aspects, of the residential area, sewage, roads, slope of the ground, surface water, green areas, historical, and land use maps. the methodology adopted in this study is principally supported using the geospatial analysis and multi-criteria analysis (mca) among the framework of gis [abdalla,207]. depends on the importance of location in the arrange. finally, the result was introduced by the mca model. various factors have been thought of so as to find appropriate areas for wastewater treatment plant the factors described criteria and parameters of the selection of the optimum site. a number of 3 teams of criteria, including the environmental, geological and economic criteria and a total of eight parameters (as above), for selecting an acceptable place for construction of wwtp. 4. criteria for site selection wastewater plant siting needs to consider many factors, and site selection refers to the process of selecting a suitable location for the facilities. the criteria according to the most world sources can be inserted as below:  distance from residential areas.  proximity to main and regional roads.  proximity to agricultural land (green areas).  proximity to drainage network (sewage system).  distance from historical areas.  distance from the river.  the location should be in a few slope areas.  some conditions for the station's location for land use. 5. gis criteria description and analysis the procedure of multi-criteria analysis "mca" for site choice of waste water treatment plant (wwtp) involves an integration and analysis of varied information. this kind of research was performed among the geospatial analysis of gis framework besides the analytical hierarchy processes (ahp). 6. results and discussions based on their importance, the main criteria are ones that have a right away influence on the chosen website. they consist of eight elements: the residential area, sewage system, roads, slope of the ground, surface water (al kufa river), green areas, historical, and land use. each criterion was zainab d abbasl and osama jassimb /al-qadisiyah journal for engineering sciences 12 (2019) 031–037 33 divided into two classes: appropriate and inappropriate. the results are shown in four stages as insert below : 6.1. first stage (input data) it contains the original maps related to the search as shown in figures (411). figure 4. land use map of the study area [4] figure 5. main roads map of the study area [made by researchers based on 4] figure 6. residential map of the study area [made by researchers based on 4] figure 7. green areas map of the study area[3] figure 8. kufa river map of the study area [ made by researchers based on 7]. figure 9. historic map of the study area [7] figure 10. sewage map of the study area[3] figure 11. slope of the ground map of the study area[7] 34 zainab d abbasl and osama jassimb /al-qadisiyah journal for engineering sciences 12 (2019) 031–037 6.2. second stage (derive dataset) it means to convert all features to raster for all layers as shown in figures (12-19). [all maps in this section made by researchers through gis program]. figure 12. land use raster figure 13. main roads raster figure 14. residential areas raster figure 15. green areas raster 6.3. third stage (reclassify datasets) reclassification of layers be within a common scale of 1-15, the higher values in the measure must be most appropriate. [all maps in this section made by researchers through gis program]. figure 16. slope areas raster figure 17. kufa river raster figure 18. historical areas raster figure 19. sewage pipes raster zainab d abbasl and osama jassimb /al-qadisiyah journal for engineering sciences 12 (2019) 031–037 35 6.3.1. reclassification distance from land the land is used for various functions like agricultural, industrial, and residential. as these areas are the most vulnerable lands, they were marked as the unsuitable class. whereas the industrial and commercial lands thought-about as less vulnerable land. other area units as such as blank lands are considered appropriate as no activities on them. the land use map of the study area shows the varied sorts of land use figure (20). figure 20. land use reclassify map 6.3.2. reclassification distance from main roads the location of the station should preferably be close to the main roads, so the areas near will take the highest scale of 15, which is the most appropriate, while the remote areas are the least appropriate number1 as shown in figure (21) figure 21. main roads reclassify map 6.3.3. reclassification distance from the residential due to inappropriate environmental conditions and creating unpleasant odors, wastewater treatment plant should be placed far from residential areas. therefore, number 15 is given to the region that farthest to the residential, which are appropriate and the number 1 for the closest which are defined as, not appropriate as shown in figure (22) figure 22. residential reclassify map 6.3.4. reclassification distance from the green areas distance from the vegetation like a forest is necessary to safeguard the worth of the lands. the station should preferably be far from the green areas therefore, number 15 is given to the region that farthest to the green areas, which are appropriate and the number 1 for the closest as shown in figure (23). figure 23. green areas reclassify map 6.3.5. reclassification distance from the surface water areas distance from the surface water is necessary to safeguard the water and fish from pollution because of the domestic use of the water in the city as drinking and farming water from the surface water. the al kufa river represent the making source of this surface water, the location of the station should preferably be away from the river so the areas farthest from the river will take the highest scale of 15, which is the most suitable while the nearby areas are the number 1 which is the least suitable as shown in figure (24) figure 24. river reclassify map 6.3.6. reclassification distance from the historical areas the station should preferably be far from the historical regions therefore, number 15 is given to the region that farthest to the historical regions, which are appropriate and the number 1 for the closest which are defined as, not appropriate as shown in figure (25) figure 25. historic roads reclassify map 36 zainab d abbasl and osama jassimb /al-qadisiyah journal for engineering sciences 12 (2019) 031–037 6.3.7. reclassification distance from the sewage areas the station should preferably be close to the sewage net, therefore, number 15 is given to the region that closest to the sewage, which are appropriate and the number 1 for the farthest which are defined as, not appropriate as shown in figure (26). 6.3.8. reclassification distance from the slope of the ground in site choice studies, the slope is a necessary element both environmentally and economically the station should preferably be on a low slope. therefore, slope layer will be reclassified and the number 15 is given to the slopes with the lowest angles, which are appropriate and the number 1 for the lowest slopes which are, not appropriate as shown in figure (27). 6.3.9. fourth stage (weight and combine ) at this stage, the layers will be weighed according to the effect ratios of each layer in the project, and then the balanced classes will be summed with each other. the output of this process is the map of the fit (map of relevance) as shown in figure (28). [map made by researchers through gis program and table 1]. 6.3.10. fifth stage (project drop on the ground) the boundaries of the appropriate areas with values 15 or close are converted to coordinates(red areas) by reclassifying the relevance map, and then transfer it to vector as shown in figure (29,30) and table (2) [ maps and table made by researchers through gis program]. table 1. weight and combine [researchers based on criteria influence]. ratio% layers no. 1 sewage 23 2 residential areas 17 3 euphrates river 15 4 main roads 11 5 historic regions 10 6 green regions 9 7 land uses 8 8 slopes 7 sum 100 table 2. coordinate of relevance region as found in arc map(10.5) figure 26. sewage pipes reclassify map figure 27. slope of the ground reclassify map figure 28. relevance map figure 29. relevance map reclassify figure 30. relevance raster to vector map zainab d abbasl and osama jassimb /al-qadisiyah journal for engineering sciences 12 (2019) 031–037 37 7. conclusions arcgis geoprocessing is an important component of arcgis and includes many processes that can be used to extract information from presented data. the study mentioned the importance of modern technologies for using it to solve environmental problems the waste water treatment plant (wwtp) within the progress of environmental protection. the methodology adopted within the study combined the techniques of the remote sensing and gis to create the study easier and to urge valuable info regarding the study space. moreover, it offers additional correct results compared to standard ways. hence, gis has verified to be a robust tool in managing special and nonspatial information in suitableness analysis. integration of gis and ahp provides best call tool in choosing acceptable wwtp in the acceptable website. eight criteria were selected, that is residential, sewage, roads, the slope of the ground, surface water, green areas, historical, and land use. a paired comparison matrix was ready for criteria. the weights were applied in linear summation equation to get a unified weight map containing due weights of all input variable. finally, all weighted maps were reclassified to urge the most effective potential website location of wwtp. the results disclosed that many of separated sites (as shown above with red color) will function sites for the wwtp. these sites wide are distributed within the north, south and west al kufa localities. the best location will be chosen according to the required land area on which the project is to be built from thirty-eight locations however, a complementary field study is critical to manifest the obtained results. during this respect, it's extremely recommendations to conduct any field survey of the chosen areas with the presence of specialized engineers to find the most effective location for wwtp between these sites and with every zone. moreover, such studies require the use of highspecial resolution remotely perceived information and gis geodatabase layers to get a lot of elaborated and good results. the adopted methodology is often applied to get optimum sites choice in similar analysis covering studies. references [1] a. al maliki, application of gis and ahp method to support of selecting a suitable site for lead pollution: a case study, misan journal for academic sciences 31 (2017) 57-69. [2] o. abdalla, s. el khidir, site selection of wastewater treatment plant using rs/gis data and multi-criteria analysis (mca): case study omdurman city, khartoum state, sudan, 2017. [3] directorate of sewage in najaf province, gis division, unpublished data, 2017. [4] directorate of municipality of kufa, gis division, unpublished data, 2007. [5] directorate of urban planning, a master plan of the city of kufa 2007. [6] directorate of the municipality of najaf, gis division, unpublished data, 2007. [7] abdel fares, nizar, manager of directorate of sewage in najaf province unpublished, 2018. [8] gis laboratory, college of urban planning, university of kufa, 2017. [9] s.i. khassaf, evaluation of ground water quality in selected area of najaf governorate for different purposes, al-qadisiyah journal for engineering sciences, 10(1) (2017) 36-53. [10] m. gorani, j. ebraheem, location optimization of wastewater treatment plants using gis: a case study in umm durman/karary, physics letters b, 27 (2012) 343-344. [11] www.http//alkufa city .net. [12] z. di, using gis-based multi-criteria analysis for optimal site selection fora sewage treatment plant, in, 2015 [13] y. zhao, y. qin, b. chen, x. zhao, y. li, x. yin, g. chen, gis-based optimization for the locations of sewage treatment plants and sewage outfalls–a case study of nansha district in guangzhou city, china, communications in nonlinear science and numerical simulation, 14(4) (2009) 1746-1757. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 742 improve performance of asphalt concrete overlay by using sbr as modified الخالصة: ان اداء الطريق االسفلتي يعتمد على خصائص االسفلت، خصائص الخلطة االسفلتية وعلى العوامل الخارجية مثل الحجم المروري والظروف الجوية. طبقة االكساء السطحية واحدة من اهم المتضررة لزيادة عمره الخدمي.هذه الدراسة تهدف الى واسرع طرق الصيانة لمعالجة الطرق اعداد خلطة اسفلتية عالية االداء تستخدم في عملية االكساء السطحية. استخدم ستايرين بيوتادين % من وزن االسفلت المستخدم ( مع العلم 9، 6، 3المطاط كمضاف لالسفلت بثالثة نسب ) تم فحص خصائص االسفلت واالسفلت المحسن .04/04ان االسفلت المستخدم ذو نفاذية باستخدام ستايرين بيوتادين المطاط والتي هي ) النفاذية ، درجة الليونة ، نقطة الوميض ، المطيلية (. وتم تقييم اداء الخلطة االسفلتية والخلطة االسفلتية المحسنة وذلك عن طريق فحص ارة. بينت نتائج الفحوصات ان استخدام مارشال واجهاد الشد غير المباشر وفحص العجلة الدو ستايرين بيوتادين المطاط كمضاف لالسفلت ادى الى تحسين اداء االسفلت والخلطة االسفلتية. % التي اظهرت الصالبة 6وكذلك بينت هذه الفحوصات ان النسبة المثالية لهذا المضاف هي % والجريان قل بنسبة 66ة االفضل للخلطات االسفلتية. ان قوة ثبات مارشال ازدادت بنسب % من المضاف وكذلك مقاومة الخلطات االسفلتية للتخدد ازداد بنسبة 6% عند استخدام 56.0 % عند استخدام نفس النسبة من المضاف.65 تم اعتماد معدل ثالث نماذج لخلطات مارشال اي عند استخدام فحصي مارشال وفحص اجهاد سم 04ن الخلطة االسفلتية عند فحص العجلة الدوارة بابعاد الشد غير المباشر وتم استخدام عتبة م سم ارتفاع )سمك(.0سم عرض و 54طول و hayder k. shanbara assis. lect. department of civil engineering al-muthanna university iraq 2012 e-mail : engineer_hayder82@yahoo.com tel : 964(0)7902274877 dr. abdulaziz a. kifae professor department of civil engineering al-muthanna university iraq 2012 e-mail : azizkifai0561@yahoo.com tel : 964(0)7803854187 dr. riadh a. abass assis. prof. department of civil engineering al-muthanna university iraq 2012 e-mail : readh_56@yahoo.com tel : 964(0)7901734941 mailto:engineer_hayder82@yahoo.com mailto:azizkifai0561@yahoo.com mailto:readh_56@yahoo.com al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 742 key words: ac overlay; performance; ac modifiers abstract the performance of asphalt concrete pavement depends on the bitumen properties, asphalt concrete mixtures volumetric properties and external factors such as traffic volume and environment. overlay is one of the quickest preventive maintenance techniques that apply to retard asphalt pavement deterioration and prolonged service lives. this study focuses on prepare good performance and flexible modified thin hot mix asphalt used as an overlay. styrene-butadiene rubber (sbr) at three contents (3, 6 & 9 % by asphalt weight) were used either alone to modify local asphalt penetration grade 40/50. properties of modified and unmodified asphalt binder (penetration, softening point, flash point and ductility) were examined. performance of modified and unmodified asphalt mixtures was evaluated through marshall, indirect tensile strength and wheel tracking test. test results showed that all properties of the base asphalt binder and asphalt mixes were improved by the addition of the modifier. the best improvements in the modified binders and modified mixes were obtained at 6% sbr. stiffness of modified asphalt mixes were improved at 6% sbr was introduced. marshall stability was increased by 26% and flow was decreased by 12.5% at 6% sbr. resistant of the modified asphalt mixes to rutting was increased by 61% at the same modifier content. the three mix types prepared and tested according to marshall method. marshall stability and indirect tensile tests were conducted on marshall specimens. wheel tracking test were conducted on (50×10×5 cm) ac mix beams. 1introduction: any asphalt pavement, when designed and constructed properly, will provide years of service. pavements continually undergo various types of stresses that induce minor or large defects into the pavement [hussain, ghaly, and ibrahim, 2008 ]. the durability of asphaltic concrete is greatly influenced by the environmental changes during the year between hot and cold temperatures and between day and night. high temperatures can soften the bitumen and consequently reduce the stiffness of asphaltic concrete making the mix more susceptible to rutting. on the other hand, low temperature can increase the stiffness of bitumen and reduce the flexibility of the asphaltic concrete, hence, inducing fatigue failure. as a result, cracking of the pavement surface may develop which adversely al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 742 affects the performance of the asphaltic concrete. thus, high temperature stiffness and low temperature flexibility are important properties in bituminous mixtures respectively to avert rutting and cracking [abdullahi,2007 ]. over the years, road structures have deteriorated more rapidly than expected due to increases in traffic volume, axle loading and tire pressure and insufficient degree of maintenance. to minimize the deterioration and increase the long-term durability of a flexible pavement, the bituminous layers should be improved with regard to performance properties, such as resistance to permanent deformation, fatigue, wear, stripping and aging. one way of increasing the quality of a flexible material layer is the use of high quality asphalt [dorina,2009]. thin hot mix asphalt (overlay) is one of the quickest preventive maintenance techniques that apply on the existing pavement to retard asphalt pavement deterioration and prolonged service lives. modifications of asphalt by the addition of flexible polymers to asphalt binder can significantly reduce these shortcomings and reduce the frequency of maintenance and provides much longer service life for maintenance treatments [hussain, ghaly, and ibrahim, 2008 ]. many different polymer modifiers for asphalt cement have been developed to help improve both the rutting and thermal cracking problems of hma by altering the properties of the asphalt cement binder. manufacturers of polymer modifiers claim the incorporation of their product with the asphalt cement binder in the manufacture of hma can significantly extend the service life of hma pavements. these polymer modified pavements are reputed to resist rutting, improve overall stability, and increase useful life. if additional service life can be achieved, then life cycle costs can be lowered, thereby allowing overall savings to the cost of maintaining pavements [gayle, william, and alfred, 1999]. the addition of polymers usually has the effect of increasing the stiffness of the binders at high service temperatures without increasing the stiffness at low service temperatures. this modification of binder properties means that the asphalt mixture could be more rut resistant at high service temperatures while its cracking resistance at low temperatures would not be lessened. crumb rubber (cr) and styrenebutadiene rubber (sbr) are two of the commonly used asphalt additives for this purpose. the purpose of this study was to conduct a laboratory evaluation of the effects of the addition of crumb rubber and sbr on the rutting resistance of typical asphalt paving mixtures used in florida [chuang-tsair, mang & byron]. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 the use of reclaimed ground tire rubber as an additive in various types of bituminous construction not only solves a waste disposal problem and offers the benefit of resource recovery, it is also of interest to the paving industry because of the additional elasticity imparted to the binder and pavement system [freddy, prithvi,., ray brown and robert,1989]. 2literature review: rutting is one of the commonly encountered distresses, and one of the most criteria of the asphalt pavement performance. in general rutting is the depression due to permanent deformation in pavement layers and subgrade under the application of repeated loading [li. and others ,1996]. the phenomenon of rutting have a longitudinal channel depression that forms in the wheel path due to compression or lateral movement of the pavement layers as a result of repeated traffic load application. rutting is a manifestation of two different mechanisms: (a) densification (volume change) and (b) shear deformation (plastic flow with no volume change). in the densification process, materials are forced downward, and shear deformation causes material to flow laterally and upward [al-juraiban, and jimenez, 1983 ]. there no absolute standards for relating rutting to safety. the problem is complex. it is not only a function of rut depth but also of vehicle speed, type of vehicle, type of tire, tire wear, porosity of the surface, intensity and duration of rainfall, cross slop of the pavement surface, etc. nevertheless some generalization can be made: the committee of the road and transportation of canada emphasizes that rut depth less than (12 mm) normally can not be a serious problem; rut depth over (25 mm) can be serious [road and transportation 1975.]. the aashto [aashto] guide determines the effects of the rut as below in table (1): use of ( 40-50 ) penetration grade asphalt results in high resistance to cracking with less permanent deformation in comparison with the results obtained for ( 60-70 ) and ( 85-100 ) penetration grades. they recommended using such kind of mixtures in west, mid and south of iraq to protect the pavement from rutting and low temperature cracking [safar, 1992], [abdul., 2000]. the increase in stiffness results in longer fatigue lives at a given stress level. the mixture variable that affects the stiffness is also going to affect the fatigue life. increasing voids reduces the fatigue life markedly by reducing stiffness and increasing stress concentrations. by al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 increasing the asphalt content, voids will be reduced and the fatigue life will be increased [pell, 1973]. asphalt rubber mixes have greater resistance to reflective cracking than conventional dense graded mixes [sousa., shatnawi, and cox, 1996]. the effect of reclaimed tire rubber on the properties of asphalt cement and asphalt concrete mixtures are studied by [fayadh, 1987]. reclaimed rubber was added or replaces the asphalt cement in an amount of 20% by weight of asphalt. she concluded that the mixtures prepared with asphaltrubber blend show a decreased resistance to stripping with a very little increase in marshall stiffness. 3materials and experimental: 3-1 materials: to obtain laboratory specimens with the same engineering characteristics as those used in pavement, the materials used in this paper are broadly used in asphalt paving industry in iraq and they are described in the following sections. 3-1-1 asphalt cement: the binder used in this paper is petroleum asphalt cement brought from daurah refinery. the physical properties of the asphalt cement are presented in table (2). 3-1-2 aggregate: the coarse aggregate (crushed) and fine aggregate as shown physical properties, chemical composition and gradation in tables (3, 4, and 5) respectively. 3-1-3 mineral filler: one type of mineral filler is used: ordinary portland cement (from kubaisa factory). it is thoroughly dry and free from lumps or aggregations of fine particles. the chemical composition and physical properties are shown in table (6). 3-1-4 styrene butadiene rubber (sbr): sbr is styrene-butadiene copolymer latex specifically designed for use in all areas of the building industry where improvements in the physical and mechanical properties of ordinary portland cement systems al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 757 are required. sbr may be used in applications which require the greater strength and flexibility characteristics given by sbr modified mixes; in areas which need a significant improvement in the bonding strength to various substrates, and where increased water impermeability and higher chemical resistance is required. 3-2 preparation of mixtures: the first step in the mix design is the determination of relative proportions of the asphalt and aggregate as well as percent of each aggregate size fractions involving filler, and the efficiency of mixing procedure which provides homogeneous mix and uniform coating of aggregate with asphalt. the mixing procedure may by divided into two stages, as described in the following articles: 3-2-1 preparation of aggregate: the aggregates are first dried to a constant weight at 110˚c, separated to the desired sizes by sieving and recombining with the mineral filler to conform the selected gradation requirements of scrb specification for surface course (2003) [state commission, 2003]. the total weight of the batch is approximately 1200gm to produce a specimen of 2.5 in. (63.5mm) height by 4in. (101.6mm) diameter. all aggregate sizes and filler are placed in the mixing bowl. the aggregate and the filler are heated before mixing to temperature of 160˚c for both conventional mixtures and that modified by sbr. 3-2-2 preparation of binder: the asphalt cement for conventional mixture is heated in an oven to the temperature of 150˚c before mixing with aggregate. the procedure which is adopted to prepare the modified binder can be outlined, as follows: the weight of sbr is determined by multiplying its percent by the required weight of asphalt content. three percentages (3,6 and 9)% of sbr by weight of asphalt cement are used in preparing modified binders. the asphalt cement with known weight is heated in an oven until it reaches a temperature of 150˚c, and the desired weights of additives are added (as quickly as possible approximately 10 second). the two components are mixed thoroughly under a temperature of (150-160˚c) until the homogeneous binder is attained. 3-2-3 preparation of mixture: after the completion of original asphalt preparation or modified binder, it is weighted to the desired amount and then added to the heated al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 aggregate and filler in the mixing bowl. all components are mixed thoroughly until all the aggregate and filler particles are completely coated with binder. the mixing temperature is maintained within the required limits of (153-158˚c)[ al-ani, jalal, and zahrah] for the conventional mixtures, and (155-165˚c) for modified mixtures [alzaiady, 1999]. 3-3 test methods: 3-3-1 preparation and test of marshall specimens: this method covers the measurement of the resistance to plastic flow of cylindrical specimens of bituminous paving mixtures loaded on the lateral surface by means of the marshall apparatus according to astm (d 1559) ["astm",1988] this method includes preparation of cylindrical specimens which are 4 inch (101.6 mm) in diameter and 2.5 +/0.05 inch (63.5 +/1.27 mm) in height. the marshall mold, spatula, and compaction hammer are heated on a hot plate to a temperature between (120-150˚c). the asphalt mixture is placed in the preheated mold and it is then spaded vigorously with the heated spatula 15 times around the perimeter and 10 times in the interior. the temperature of the mixture immediately prior to compaction is between (142-146˚c)[ al-ani, jalal, and zahrah]. then, 75 blows on the top and bottom of the specimen are applied with a compaction hammer of 4.535 kg sliding weight, and a free fall in 18 inch (457.2 mm). the specimen in mold is left to cool at room temperature for 24 hours and then it is removed from the mold. marshall stability and flow tests are preformed on each specimen. the cylindrical specimen is placed in water bath at 60˚c for 30 to 40 minutes, then compressed on the lateral surface at constant rate of 2in/min. (50.8mm/min.) until the maximum load (failure) is reached. the maximum load resistance and the corresponding flow value are recorded. three specimens for each combination are prepared and the average results are reported. the bulk specific gravity density astm (d 2726) ["astm",1988], and theoretical (maximum) specific gravity of void less mixture are determined at the laboratory. the percent of air voids is then calculated. 3-3-2 preparation and test of indirect tensile strength specimens: the specimens are prepared in the same procedure given in article (3-2) for the marshall mix design method. the tensile strength of compacted asphalt specimens is typically determined by the indirect tensile strength test, which is determined according to method described in astm d4123 ["astm",1988]. the prepared specimens are left to cool at room temperature for 24 hours and then placed in a water bath al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 754 maintained at the test temperature for 30 minutes in order to bring them to the specified test temperature. to accomplish indirect tensile test, the specimens are removed from water bath and immediately placed into the loading apparatus. the compressive load is applied to two opposite loading strips of (12.7mm) wide and (63.5mm) long made of steel to distribute the load and maintain constant loading area. each strip is curved at the interface with the specimen and has a radius equal to that of the specimen. the two loading strips are kept parallel to and centered on vertical diametrical plane. this loading configuration develops a relatively uniform tensile stress perpendicular to the direction of the applied load and along the vertical diametrical plane that ultimately causes the specimens to fail by splitting a long the vertical diameter. the compressive load is applied at a constant rate of 2inch/min. (50.8mm/min) and the ultimate load at failure is recorded. figure (1) shows load configuration and failure plane for specimen in indirect tensile test. the indirect tensile strength (its) is calculated, as follows: dt p sti ult .. 2 ..   (3-1) where: i.t.s = indirect tensile strength (kpa). pult = ultimate applied load at failure (kn). t = thickness of specimen (m). d = diameter of specimen (m). 3-3-4 wheel tracking test: the wheel tracking apparatus, is manufactured in iraq to simulate the effect of traffic loading on asphalt concrete overlay[technical, 2002] the beam of asphalt mixture has a length of 500 mm, a width of 100 mm, and a height of 50 mm and it is rested on two concrete blocks. the concrete blocks rest on 35cm of compacted soil and subbase layers. to obtain an asphalt beam with the mentioned dimensions, approximately 5952.5 gm of asphalt mixture is prepared using electrical mixer. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 755 to obtain the required beam density as marshall specimens bulk density, static compaction is used by compression machine with different applied loads at the rate of 2.5mm per minute. 4resuls and discussion: 4-1 properties of asphalt concrete mixtures: the properties of asphalt concrete mixtures, such as, marshall properties (marshall stability, flow, bulk density, air voids, voids filled with asphalt, voids in mineral aggregate, marshall stiffness), indirect tensile strength, and number of wheel passes, have been investigated to evaluate performance of asphalt concrete mixtures. 4-2 optimum asphalt concrete mixtures: five different percentages of asphalt contents (4.25, 4.75, 5.25, 5.75 & 6.25) % by weight of mixture and 12.5 mm aggregate maximum size are used with portland cement as a filler. the relations between asphalt content and marshall properties are typical to common trend in asphalt content mixes. the optimum asphalt content is 5%, it is determined from three marshall properties (stability, bulk density, and 4% air voids) and checked with the other marshall properties of flow, vma, and vfa to be within the specification limits of scrb shown in table (7). 4-3 marshall stiffness: the marshall stiffness is calculated as the ratio between marshall stability and corresponding flow for the different mixtures (table 8) [19]. increased values of marshall stiffness have been obtained by increasing marshall stability (with the same value of flow) or decreasing flow (with the same value of marshall stability). marshall stiffness can be increased by using harder asphalt grade and compaction efforts, compaction temperature, mixing temperature high enough and within the acceptable limits of specification. 4-4 effect of sbr content on the properties of asphalt concrete mixtures: three percentages (3, 6 and 9 %) of sbr modifier are added to asphalt concrete mixture at optimum asphalt content for 12.5 mm aggregate maximum size, and the tests described in following articles were conducted: al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 4-4-1 marshall test result: 4-4-1-1 marshall stability: figure (2) illustrates the relationship between marshall stability and sbr content. it is obvious that there is an optimum sbr content which yields maximum marshall stability, and this value is 6%. the higher stability value was obtained with mixes modified with 6% sbr, this is because the addition of sbr to the asphalt binder increased its stiffness and reduced its viscous at high service temperature. 4-4-1-2 marshall flow: figure (3) shows that there is a decrease in the values of marshall flow as the percentage of the sbr content is increased. this is may be due to the stiff nature of sbr comparing to the base asphalt. 4-4-1-3 bulk density: figure (4) shows that the bulk density increased when the sbr percentages are increased until 9% sbr then decreased. the increase in additive may separate the coarse aggregate particles and hence decrease the density. this increase in bulk density may be due to the decreased in air voids content of such mixes. 4-4-1-4 air voids: figure (5) shows that the air voids decrease when the sbr are increased. this behavior illustrates the increase in bulk density. this may be as mentioned above due to compaction problems. it is also clear that mixes modified with sbr have lower air voids than conventional mixes. this may be due to that the sbr particles dissolved completely in bitumen during the modifying process, which led to decrease in the air voids percentage. 4-4-1-5 voids in mineral aggregate (v.m.a.): figure (6) shows that the v.m.a. decrease when the sbr are increased until 9% and this behavior illustrates the increase in bulk density. 4-4-1-6 voids filled with asphalt (v.f.a.): figure (7) shows that the v.f.a. increase when the sbr are increased until 9%. 4-4-1-7 marshall stiffness figure (8) shows the marshall stiffness with optimum asphalt content for three percentages of sbr. it is seen from this figure that the marshall stiffness increases when the sbr are increased. this is can be al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 attributed to the increases in marshall stability and the decrease in marshall flow. 4-4-2 effect of sbr content on indirect tensile strength test: figures (9) show the effect of mixtures modified with sbr on indirect tensile strength at 25˚c. this figure show that the indirect tensile strength increases when the sbr are increased up to 9% then they are decreased. this behavior is similar to the behavior of marshall stiffness. after analyzing the percentages of sbr that affect the properties of the mixtures, an optimum percent of sbr modifier could be selected from the indirect tensile strength, marshall properties, and marshall stiffness, and this percentage can be used in the physical tests of asphalt binder and the wheel tracking test. the optimum percentage of sbr modifier is selected to be 6% by weight of asphalt content. 4-4-3 effect of sbr content on physical properties of asphalt binder: table (9) shows the effect of 6% sbr on physical properties of asphalt binder: 4-4-4 effect of optimum sbr content on number of wheel passes: the results of the wheel tracking test are displayed in table(10). it can be seen that the sbr modified asphalt mixtures show the highest reduction in rut depth as compared with the unmodified control mixtures (up to 66% at 10000 cycles). al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 table (10) effect of sbr on rut depth 5conclusions: 1. the results of this laboratory study show that the addition of sbr could increase the rutting resistance of asphalt paving mixtures. 2. the increase in marshall stability is an important factory in via of high traffic load besides the resistant to rutting. 3. the modified mixtures exhibited substantially lower rut depths in the loaded wheel tests than the unmodified mixtures. 4. using sbr improve the marshall and physical properties and rut resistance for modified asphalt binder and mixtures. 5. sbr can be used as flexible materials for asphalt binder modification. 6. asphalt additives improve durability, crack & rut resistance, asphalt binder elasticity as well as increase the pavement life. 6references: 1. hussain, m. h. m., ghaly, n. f. and ibrahim, i. m., 2008. modified hot mix asphalt for road maintenance. world applied sciences journal 5 (2): 236-245, 2008, issn 1818-4952. egyptian petroleum research institute. 2. abdullahi, a. m., 2007. a study on the physical and mechanical properties of asphaltic concrete incorporating crumb rubber produced through dry process. thesis submitted in fulfillment of the requirements for the degree of doctor of philosophy. 3. dorina, a. a., 2009. the effect of epoxy bitumen modification on hot mix asphalt properties and rut resistance. a project report submitted in partial fulfillment of the requirements for the award of the degree of master of engineering. university technology malaysia. 4. gayle, e. a., william, f. b. and alfred, b. c., 1999. polymer modified hot mix asphalt field trial. mississippi department of transportation research division. average rut depth ( mm ) reduction in rut depth compared with base ac at 1000 cycles at 5000 cycles at 10000 cycles control mix 4.7 8.3 10.7 6% sbr 2.3 5.1 7.1 59% al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 752 5. chuang-tsair shih, mang tia & byron e. ruth. evaluation of the effects of crumb rubber and sbr on rutting resistance of asphalt concrete. department of civil engineering, university of florida. 6. freddy, l. r., prithvi, s. k., e. ray brown and robert, l. d., 1989. investigation and evaluation of ground tire rubber in hot mix asphalt. national center for asphalt technology. ncat report no. 89-3 7. li. shove and others. a study of properties of asphalt mix related to rutting performance using wheel tracking test. proceedings of 1996 international road federation asia – specific regional meeting, vol. iv, pp.91. 8. al-juraiban, s. a., and jimenez, r. a., 1983. rutting properties of a dune-sand paving mixture. trb 911, p.11. 9. road and transportation association of canada (pavement management guide), 1975. 10. aashto guide for design of pavement structure 11. safar, m. m., 1992. influence of temperature on performance of paving materials. m.sc. thesis, university of baghdad, iraq. 12. abdul majeed, r. z., 2000. influence of asphalt overlay variables on pavement performance. m. sc. thesis, university of baghdad, iraq. 13. pell, p. s., 1973. characterization of fatigue behavior. highway research board special report 140, pp.49-63. 14. sousa, j. b., shatnawi, and cox. j., 1996. an approach for investigating reflective fatigue cracking in asphalt – aggregate overlays. proceedings of the third international pilem conference on reflective cracking in pavements, delft university of technology and belgian road research center, october, pp. 103-112. 15. fayadh, s. s., 1987. hydrated lime and rubber as additives in asphalt paving. m.sc. thesis, university of baghdad. 16. state commission of roads and bridges ( scrb ). hot mix asphalt concrete pavements. iraq standard specification, ministry of housing and construction, department of design and study, section r9, revised edition (2003). 17. al-ani, h. m. h., jalal, a. a. and zahrah, a. h. temperature susceptibility of paving grade asphalt cement. scientific journal published by the university of technology, baghdad, vol.4, no.2. 18. al-zaiady, n. n., 1999.the use of reclaimed tires rubber modified asphalt in asphaltic concrete mixes. m. sc., thesis, university of technology, iraq. 19. "astm", annual book of astm standers, section 4, volume al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 722 04.03, 1988. 20. technical manual, 2002. advanced fiber glass technology for asphalt pavement overlays. canadian patent 1240873. table (1) rut depth according to aashto table (2) physical properties of asphalt cement. test unit penetra. grade (40-50) scrb spec. for (40-50) pen. grade penetration (25˚c, 100g, 5sec) astm d5. 1/10 mm 45 40-50 ductility (25˚c, 5 cm/min). astm d 113. cm >100 100 softening point (ring & ball). astm d 36. ˚c 52 50-60 flash point (cleave land open cup) astm d92 ˚c 328  240 after thin-film oven test astm d 1754 penetration of residue. 1/10mm 33 ductility of residue. cm >100 100 + loss in weight (163˚c, 50 gm, 5h),% % 0.18 75.0 table (3) physical properties of aggregates property coarse aggr. fine aggr. bulk specific gravity (astm c127 and c128). 2.610 2.631 apparent specific gravity (astm c127 and c128). 2.641 2.6802 percent water absorption (astm c127 and c128). 0.423 0.542 percent wear (los-angeles abrasion) (astm c131) 20.10 …… mean rut depth 0.6 – 1.3 cm 1.3 – 2.5 cm >2.5 cm severity level low medium high al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 722 table (4) chemical composition of aggregates chemical compound % content silica,sio2 82.52 lime, cao 5.37 magnesia, mgo 0.78 sulfuric anhydride, so3 2.7 alumina, al2o3 0.48 ferric oxide, fe2o3 0.69 loss on ignition 6.55 total 99.09 mineral composition quartz 80.3 calcite 10.92 table (5) gradation of the aggregate for 12.5mm a.m.s. percentage passing by weight of total aggregate sieve opening mm sieve size surface or wearing course mid point gradation specification limit [scrb] 100 100 12.5 1/2 '' 95 90-100 9.5 3/8 '' 70 55-85 4.75 no.4 49.5 32-67 2.36 no.8 15 7-23 0.3 no.50 7 4-10 0.075 no.200 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 727 table (6) chemical composition & physical properties of cement filler types used. chemical compound % content silica,sio2 21.51 lime, cao 62.52 sulfuric anhydride, so3 1.58 alumina, al2o3 5.64 magnesia (mgo) 3.77 ferric oxide, fe2o3 3.35 loss on ignition (l.o.i) 1.34 total 99.44 physical properties %passing sieve no. 200 98 apparent specific gravity 3.13 specific surface area(m 2 /kg) 356 table (7) s.c.r.b. specification limits and at 5% o.a.c 12.5mm a.m.s s.c.r.b specification limits properties 10.8 8 minimum marshall stability (kn) 2.321 bulk density (gm/cm 3 ) 3.2 2-4 marshall flow (mm) 4.1 3-5 air voids (%) 74 65-85 voids filled with bitumen (%) 16.3 14 minimum voids in mineral aggregate (%) table (8) marshall stiffness of conventional mixes at o.a.c. 12.5mm a.m.s. type of mix 3.375 marshall stiffness (kn/mm) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 722 table (9) effect of sbr content on physical properties of asphalt sbr content % penetration 0.1 mm softening point ˚c ductility cm 0 (control) 45 52 > 100 3 45 53 > 100 6 44 57 > 100 9 42 63 > 100 figure (1) load configuration and failure plane for specimen in indirect tensile test figure (2) effect of sbr content on marshall stability 8 9 10 11 12 13 14 15 0 3 6 9 sbr content (%) s ta b il it y ( k n ) load failure plane marshall specimen loading strip (12.7mm wide) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 724 figure (3) effect of sbr content on marshall flow figure (4) effect of sbr content on bulk density 2 2.2 2.4 2.6 2.8 3 3.2 3.4 0 3 6 9 sbr content (%) f lo w ( m m ) 2.3 2.32 2.34 2.36 2.38 2.4 0 3 6 9 sbr content (%) b u lk d e n si ty ( g m /c m 3 ) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 725 figure (5) effect of sbr content on air voids figure (6) effect of sbr content on v.m.a 3 3.2 3.4 3.6 3.8 4 4.2 4.4 0 3 6 9 sbr content (%) a ir v o id s (% ) 14 14.5 15 15.5 16 16.5 17 0 3 6 9 sbr content (%) v m a ( % ) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 722 figure (7) effect of sbr content on v.f.a figure (8) effect of sbr content on marshall stiffness 70 75 80 85 0 3 6 9 sbr content (%) v f a ( % ) 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5 0 3 6 9 sbr content (%) m a rs h a ll s ti ff n e ss ( k n /m m ) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 722 figure (9) effect of sbr content on indirect tensile strength at 25°c 1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500 0 3 6 9 sbr content (%) in d ir e ct t e n si le s tr e n g th ( k p a ) microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 31 some mechanical properties of concrete reinforced with reed fibers ali hasson nahhab collage of engineering university of babylon abstract this research produces a new results about using of locally available reed fibers in concrete. the main parameter of this study was the volume fraction of fibers. the reed fibers were added to the mix in percentages of 1, 2, 3, 4,and 6%. the test program included: slump, compressive strength, splitting tensile strength and impact resistance. it was found that the presence of reed fibers leads to reduce workability, compressive, splitting tensile and impact strength. it was also found that, generally, this reduction increases as the volume percentage of fibers is increased. keywords: reed fibers, impact resistance, compressive strength, splitting tensile strength بعض الخواص الميكانيكية للخرسانة المسلحة بألياف القصب علي حسون نهاب آلية الهندسة جامعة بابل الخالصة المتغير الرئيسي في هذه الدراسة هو . يقدم هذا البحث نتائج جديدة حول استخدام ألياف القصب المتوفرة محليا في الخرسانة تضمن برنامج العمل فحوصات الهطول و مقاومة االنضغاط % . 6 و4 و3و 2و 1 بنسب أضيفتالنسبة الحجمية لأللياف حيث النتائج إن وجود ألياف القصب في الخلطة يؤدي إلى نقصان آل من قابلية أظهرت. ومقاومة الشد االنشطاري ومقاومة الصدم امة يزداد هذا النقصان بزيادة النسبة الحجمية التشغيل و مقاومة االنضغاط ومقاومة الشد االنشطاري ومقاومة الصدم وبصورة ع . لأللياف introduction there has been a rising interest in utilizing natural fibers for making low cost building materials in latest years. some investigations (aziz et.al, 1981, mansur and aziz, 1982, mansur and aziz, 1983, soroushian et. al, 1995 ) have previously been carried out on various mechanical properties of concrete materials using natural fibers from coconut, husk,sisal,bamboo, jute and cellulose fibers. these researches have shown encouraging results such as improved tensile and flexural strength of the matrix. only very few studies have been carried out to use reed fibers for making a suitable building materials (raouf and mahdi, 2005) . ( raouf, 1986) studied some mechanical properties of a reed. he concluded that the modulus of elasticity and tensile strength are relatively low and vary from 10 to 43 kn/mm2 and 89 to 144 n/mm2, respectively. (raouf and mahdi, 2005) investigated the flexural behavior of reed reinforced concrete. they used concrete prisms (100*100*1000mm) reinforced with five strips of the reed (10mm wide and al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 32 3mm thickness). they concluded that the reed reinforcement does not affect the modulus of rupture but it changing the nature of failure from brittle to ductile. in the present research, an attempt has been made to produce a concrete reinforced with reed fibers . test program this study consisted of determining the workability, compressive strength, splitting tensile strength, and impact resistance of reed fiber reinforced concrete. the concrete mix given in table 1 was designed according to aci committee 544 recommendations (1988, 1993). materials it is known that fibers have been produced from steel, plastic, glass, and natural materials in different shapes and sizes( aci committee 544.1r,1982). in addition, when used in concrete, they should be discontinuous and discrete. in this research, the reed fibers, which are a type of natural fibers, were used. they were cut to the length of 60 mm and width of 5mm. the thickness was 1 mm. the average tensile strength and density of the fibers was 105 mpa and 580 kg / m3, respectively. ordinary portland cement produced in india conforming to iraqi specification (ios) no.5 : 1984 was chosen. the compressive strength of this cement was 28.2 and 34.7 mpa at 3 and 7 days respectively. the fineness (blaine) was 321 m2/ kg. the fine aggregate consisted of natural sand. the coarse aggregate from a type of gravel and 10 mm maximum was used. they conform to (ios) no.45:1984. test specimens the following specimens were made: 1eighteen (152mm) compression cubes. 2eighteen (152mm * 305mm) splitting tension cylinders. 3eighteen impact specimens (152 * 64 mm). test for plastic and hardened concrete the freshly mixed concrete was tested for slump according to astm c 143. the hardened concrete was tested for compressive strength , splitting tensile strength , and impact resistance at age of 28 days . the compressive strength test was carried out according to b.s 1881 part 116 :1983. the splitting tensile strength was determined according to astm c 496. the impact resistance was measured by using the operation shown in figure 1 which is recommended by (aci committee 544.2r, 1988 ). it consisted of (1) a standard 4.54 kg compaction hammer with a 475 mm drop ( astm d1557), (2) a 64 mm diameter steel ball, and (3) a base plate with a positioning bracket and four positioning lugs. the specimen is placed on the base plate within the positioning lugs with its smooth surface down. the bracket is then bolted in place and the hardened steel ball is placed on top of the specimens. the compactor is placed with its base up on the steel ball. the test was performed on a smooth rigid floor to minimize loss due to bouncing . the hammer is dropped consecutively and the number of blows required to cause ultimate failure are recorded. ultimate failure is reached when the cracks have opened sufficiently to make the specimen touch three of the four positioning lugs at the base plate. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 33 results and discussion a summary of the data obtained in the fresh and hardened tests is presented in table 2. slump test results figure 2 shows the measured values of slump of fresh plain and fibrous mixes versus volume fraction of reed fibers . it is obvious from the figure that fresh mix workability is damaged by increasing the volume fraction of reed fibers. the reason of this behavior is that a part of mixing water is absorbed by the fibers. additionally , interparticle friction of fibers and fibers and aggregates is an other factor reducing fresh mix workability of reed fiber reinforced concrete. compressive strength test results in figure 3, the effect of reed fiber volume fraction on the compressive strength of concrete is shown. it can be seen that the presence of reed fibers is associated with decrease in strength. this decrease is 6.7, 27.3, 33.5, 34.4, 52.3% at 1, 2, 3, 4,6% fiber volume fraction, respectively. this can be attributed to the interlocking of fibers and consequently, formation of fiber balls which can be decreasing the density and then the strength of concrete. splitting tensile strength test results the results of splitting tensile strength as a function of volume percentage of fibers is plotted in figure 4. it can be observed that the splitting tensile strength decreases with increasing the percentage of reed fibers. this reduction may be attributed to the reduction in workability of the mixes and presence of fibers balling during mixing which lead to incomplete compaction and more voids. on the other hand , the comparatively low tensile strength and modulus of elasticity of this type of fibers is the reason of the no positive effect of this type of fibers on the tensile properties of concrete . impact resistance test results the influence of reed fiber content on the impact resistance at failure is shown in figure 5. it can be seen from the figure that the presence of reed fibers in the concrete mixes gives a reduction in the impact resistance. the maximum reduction occurs at 2% volume of fibers and it is about 35.5 % comparing to the plain mix. the reason of this reduction is that the fibers tended to cluster together resulting in a more voids and less density. again, as with the splitting tensile strength, the explanation of the no encouraging effect of the reed fibers on the impact resistance is the low its tensile strength and modulus of elasticity. conclusions this study investigates the effect of volume fraction on the workability, compressive, splitting tensile and impact strength of reed fiber reinforced concrete. the results have indicated that a decrease in workability, compressive, splitting tensile and impact strength could be achieved by the inclusion of reed fiber in concrete. it was found that this reduction is more pronounced when the amount of fibers is increased except that for impact resistance which is not follow the same trend. the decrease in compressive strength is varied from 6.7 and 52.3 % at 1 and 6 % volume percentage of fibers, respectively while that for splitting tensile strength is 3.5 to 40 %. the maximum decrease in impact resistance occurs at 2 % volume of fibers . this decrease is 35.5 % relative to the corresponding plain specimens. . al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 34 references aci committee 544 1r, (1982) , state-of-the-art report on fiber reinforced concrete, concrete international, vol.4, no.5, may, pp.9-30. aci committee 544 2r, (1988) , measurement of properties of fiber reinforced concrete , aci materials journal, vol.85, no.6, nov.-dec., pp.583-593. aci committee 544 3r, (1993), guide for specifying, proportioning , mixing, placing, and finishing steel fiber reinforced concrete, aci materials journal, vol.90, no.1, jan.-feb.1993, pp.94-101. aziz, m.a, paramasivam, p., and lee, s.l., ( 1981), prospects for natural fiber reinforced concrete in construction, the international journal of cement composite and lightweight concrete, vol.3, no.2, pp.123-132. mansur, m.a., and aziz, m.a, ( 1982), a study of jute fiber reinforced cement composite, the international journal of cement composite and lightweight concrete, vol.5, no.3, pp.75-82. mansur, m.a., and aziz, m.a, ( 1983), study of bambo-mesh reinforcedcement composites, the international journal of cement composite and lightweight concrete, vol.5, no.3, pp.165171. rouf, z.a., and mahdi, n., (2005), flexural behavior of reed reinforced concrete, engineering journal, vol.11, no.1, pp.1-7. rouf, z.a., (1986), structural qualities of reed –reinforced concrete, nccl, baghdad, oct. soroushian, p., marikunte, s., and won, j., (1995), statistical evaluation of mechanical and physical properties of cellulose fiber reinforced cement composites, aci materials journal, vol.92, no.2, march-apr., pp.172-180. table 1 : mix proportions, kg/ m3 reed fibers, percent by volume water cement sand gravel 1 2 3 4 6 234 427 768 939 6 12 18 24 36 table 2 : the test results mix vf (%) slump (mm) 28 days compressive strength (mpa) 28 days splitting tensile strength (mpa) 28 days impact strength (number of blows) 1 0 160 32.5 3.67 45 2 1 150 30.3 3.54 41 3 2 140 23.6 3.20 29 4 3 80 21.6 2.87 33 5 4 60 21.3 2.63 32 6 6 40 15.5 2.20 40 al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 35 64 mm dia. steel ball figure 1: impact test apparatus 0 1 2 3 4 5 6 vf (%) 0 20 40 60 80 100 120 140 160 180 200 s lu m p (m m ) figure 2 : effect of volume fraction of reed fibers on the slump of concrete base plate al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 36 0 1 2 3 4 5 6 vf (%) 0 5 10 15 20 25 30 35 40 c om pr es si ve s tre ng th ( m p a) figure 3 : effect of volume fraction of reed fibers on the compressive strength of concrete 0 1 2 3 4 5 6 vf (%) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 s pl itt in g te ns ile s tr en gt h (m p a) figure 4 : effect of volume fraction of reed fibers on the splitting tensile strength of concrete al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 37 0 1 2 3 4 5 6 vf (%) 0 10 20 30 40 50 60 im pa ct re si st an ce ( n um be r of b lo w s) figure 5 : effect of volume fraction of reed fibers on the impact resistance of concrete al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 27 study the effect of two base fluids distilled water and ethylene glycol on the physical properties of nanofluids containing cu, al and zr2o3 nanoparticles khalid faisal sultan lecture department of electromechanical engineering university of technology e– mail: ksultan.61@yahoo.com received 25 september 2013 accepted 19 january 2014 abstract in this investigation the thermal properties of nanofluids and three types of nanoparticles which are ((cu 25 nm)+ e g), (al(30nm)) + e g) and (zr2o3 (50nm) + eg) was studied using two types of base fluids (ethylene glycol and distilled water). ethylene glycol was proven to be better than distilled water – based fluid in the nanofluids for having two properties which are thermal conductivity and specific heat, while distilled water was better than ethylene glycol for having two properties which are density and viscosity. the rates of increase in thermal conductivity in this research are 45%, 22 % and 7.25 % to each of the cu/ dw, al / dw and zr2o3 / dw respectively, while these percentages are 30 %, 17 %, 4.5 % and to all of the cu / eg, al/eg and zr2o3 / eg respectively at 2.5% vol a concentration and that the cause of this increase for cu / eg is that the small size of the particles cu (25nm), while the viscosity of zr2o3 / eg is larger than cu / eg and al/ eg due to the large size of the particles zr2o3 (50nm). the specific heat capacity of nanofluid made by ethylene glycol and cu (25nm), al (30nm) and zr2o3 (50nm) nanoparticle inclusions measured at room temperature were compared with two kinds of models for determination of the specific heat capacity of nanofluid. the result indicates that the specific heat capacity of cu (25nm), al (30nm), zr2o3 (50nm) nanofluid decreases gradually with increasing volume concentration of nanoparticles. it can be found that there is almost linear relation between shear stress and shear rate for all concentrations of nanofluids which confirm a newtonian behavior for cu / eg, al/eg and zr2o3/ eg in volume fraction 0.25 and 2.5 % vol as well as cu / dw, al/ dw and zr2o3/ dw. اثيلين كاليكول( على الخواص الفيزيائية للموائع و نقي دراسة تأثير تغير مائع االساس)ماء الزركونيوماوكسيد و , االلمنيومالنحاسالنانوية التي تحتوي على جزئيات د. خالد فيصل سلطان مدرس قسم الهندسة الكهروميكانيكية التكنلوجيةالجامعة الخالصة تم التحقق في هذا البحث من الخواص الحرارية للموائع الفائقة الدقة والى ثالثة أنواع من الجزئيات الفائقة الدقة mailto:ksultan.61@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 28 وهي zr2o3 (50nm) +eg) , (al (30nm) + eg) , (cu (25nm) + eg) اء نقي وبيان أيهما أفضل في الموائع الفائقة الدقة حيث ثبت أن وباستخدام نوعين من مائع األساس هما اثيلين الكاليكول وم يكون ابينم . اللزوجةوالكثافة, وللخاصيتين هما الدقة كمائع أساس في الموائع الفاقة أثيلين الكاليكول يكون أفضل من الماء النقي . أن نسب الزيادة في والحراة النوعية لحراريةالموصلية ا وللخاصيتين هماأثيلين الكاليكول أفضل كمائع أساس من الماء النقي %7.25 , %22 , %45الموصلية الحرارية في هذا البحث هي كل من والى al/dw , cu /dw zr2o3 / dw بينما %4.5 , % 17, % 30 النسبكانت هذه من كل والى zr2o3 /eg, al/eg, cu /eg تركيز وعند 2.5vol% وان يادة بالنسبة إلى سبب هذه الز cu /eg هو أن حجم جزئيات cu (25nm) اللزوجةفي حين كانت الصغيرة zr2o3 /eg هي من لزوجة األكبر cu/eg, al /eg جزئيات بسب حجم zr2o3 (50nm) إلى. كما بينت النتائج ان الحرارة النوعية يرةالكب كذلك الحال الى ص تدريجيا مع زيادة تركيز الجزيئاتتتناق (zr2o3/eg, al/eg, cu /eg) ,الموائع الفائقة الدقة (zr2o3/dw, al/dw, cu /dw) الموائع الفائقة الدقة هي موائع نيوتينية من خالل العالقة الخطية أن أيضا وبينت الدراسة .القص ومعدل القص أجهادبين keywords: nano fluid, ethylene glycol, distilled water, newtonian numenclature e heat loss watt i current a v voltage v d thickness of the discs mm r the radius of the disc mm ds thickness of the sample mm t1, t2, t3 the temperatures of the through discs. k dw distilled water __ eg ethylene glycol __ k thermal conductivity of nanofluid w/m 2 .k ф volume fraction % subscripts nf nanofluid __ b base __ 1. introduction nanofluids, produced by dispersing nanoparticles into conventional heat transfer fluids, are proposed as the next generation heat transfer fluids due to the fact that their thermal conductivities are significantly higher than those of the base liquids [1]. subsequently more than 16 laboratories worldwide have published experimental data on the thermal conductivity of nanofluids. the colloidal fluidic systems show unusually high thermal conductivity provided they are prepared in a suitable stable manner. at present the thermal conductivity data measured by different groups are scattered. even for the same nanofluids, different groups reported different enhancements [2]. for instance, lee et al. [3] reported an increase in thermal conductivity ratio of 14% compared to pure water with 3.5 vol. % cuo particles, al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 29 while eastman et al. [4] obtained a 40% increase at the same volume fraction. masuda et al. [5] published results on the thermal conductivity of al2o3–water nanofluid as early as 1993. the average size of their al2o3 nano particles used is about 13 nm. their measurements gave a 30% increase at the particle loading of 4.3 vol.%, which was more than 20% higher than that reported by lee et al. [3]. some researchers' results [6, 7] showed that the thermal conductivities of nano fluids were strongly dependent on the size of the suspended particles, with the conductivities decreasing with nano particle sizes. while xie's results [8] showed that the 60 nm particles gave about twice the enhancement as compared to the 15 nm particles, which was contrary to the former stated influence of the particle size. hong's conclusion [9] was similar to that of xie's[8]. in hong's opinion suspensions containing small nano particle clusters are more effective in improving thermal conductivity than that of individual dispersed nano particles because the clustered nano particles may provide a long path for heat transfer. similar scattered phenomena occur in the study of the mechanisms of the thermal conductivity enhancements in nanofluids. the above facts demonstrate that several factors affect the measured thermal conductivity values, such as the temperature of fluid, particle size, the settlement time after nanofluid preparation and the stability of nanofluid. it should be noted that the stability of nanofluid is vital, because it not only affects the accuracy of measurement for the thermal conductivity of nano fluid, but also affects its application in heat transfer systems when nanofluid is used as the substitute for conventional thermal fluid. choi [10] reported that the cu/ethylene glycol nano fluid with 0.3% volume of cu nanoparticles can enhance thermal conductivity up to 40%. in the present paper, we prepared stable nanofluids containing cu, al, and zr2o3 nanoparticles through a two – step method. the thermal transport properties including thermal conductivity, viscosity, density and specific heat were measured experimentally and compared with that obtained using empirical correlation for many researchers in this field and were studied the effects of the concentration, size and type nanoparticles on enhancement of heat transfer. 2. sample preparation nanofluid samples were prepared by dispersing pre – weighed quantities of dry particles in both deionized water and ethylene glycol. the ph of each nanofluids mixture was measured. the mixtures were then subjected to ultrasonic mixing [60 khz, 150 w at 25 – 30 o c, toshiba, england] for several minutes to break up any particle aggregates. the acidic ph is much less than the iso electric point of these particles, thus ensuring positive surface charges on the particles. the surface enhanced repulsion between the particles, resulted in uniform dispersions for the duration of the experiments. an images of nanofluids containing cu (25nm), al (30nm) and zr2o3 (50nm) are displayed in fig.(1). in this study (1gm) of nanoparticles was mixed with (250 ml) pure water and ethylene glycol. figure(1): image for ethylene glycol – based nanofluids containing al, cu and zr2o3 nanoparticles zr2o3+ eg cu+ eg al+ eg ethylene glycol al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 30 3. experimental properties of the nanofluids thermal properties of nanofluids with the three types of nanoparticles al, cu and zr2o3 using two types of base fluids (distilled water and ethylene glycol) have been measured using the laboratory apparatus. the conductivity thermal, dynamic viscosity, specific heat, density have been compared with these obtained from correlation equations developed by many researchers in this field and measurement of these properties was as follows. a. measurement of the viscosity in this study, measurement of viscosity in practice where found that there is a very little difference between the practical and empirical relations used by researchers such as einstain model [11], brinkman model [12] ,wang et al. model[13] , batchel model[14]. the wang et al. model is the closest to practical by a difference not exceeding 1.72%. where the measured viscosity for three types of nanofluids (cu (25nm) +eg), (al (30nm)+eg) and zr2o3 (50nm)+eg) with by different volume fraction and found the viscosity increase with concentration increasing. as well as to measure the viscosity ,measuring of the shear stress and the strain rate and the accuracy be ± 1% and the device which used to measure these variables brook field digital viscometer model dv e as shown in fig (2). the principle of operation of the dv – e is to rotate a spindle (which is immersed in the test fluid) through a calibrated spring. the viscous drag of the fluid against the spindle is measured by the spring deflection. spring deflection is measured with a rotary transducer which provides a torque signal. the measurement range of a dv – e (in cent poise or milli pascal seconds) is determined by the rotational speed of the spindle. the viscosity of the ethylene glycol and distilled water (60:40% by weight was measured before the addition any of types the three of nanoparticles. the obtained readings were compared with data from the american society of heating, refrigerating and air – conditioning engineers (ashrae) hand book [15], see fig. 3. the ashrae data and the experimental values match nicely (maximum difference of ± 2%) with temperature ranging from 20 0 c to 55 0 c. measurement of the specific heat the specific heat of the nanofluid was measured using colorimeter as shown in fig (4).the comparison between two models of specific heat is used in all researches by this field [16, 17], where the second model is the closest to the practical and a difference of 2.65%. measurement of the thermal conductivity the used apparatus for measuring the thermal conductivity of a nanofluid is (thc – 101) type and shown in fig(5). where using lee's disc method for measurement of the thermal conductivity for nanofluids. where three types used nanofluids are revealed in fig (6), and the disc that was used in the experiments is shown in fig (7). this method can be used for a wide range of temperatures and summary this method putting the model which want measurement thermal conductivity between two discs of brass (1, 2) and be thermal conductivity by heater coil and connecter to the power apparatus, the heater is switch on from the power supply with ( v = 6 v and i = 0.2 a) to heat the brass disks (2 and 3) and the temperatures of the all disks increases in nonlinear relationships and at different rates with the time according to its position from the heat source. the schematic diagram for this method is depicted in fig (8). put the device in the place of tightly closed to constant the temperature of the environment and after period of time arrived two discs (2,3) to the equilibrium and that any irregularity in the sample disc result of not access to an equilibrium state and if you know the temperature of the al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 31 discs (1,2,3) and the thermal energy which passing through the coil can be calculated the thermal conductivity in the following form.[ 17,18 ].                    2111 12 tds 2 1 tds 2 1 d r 2 te ds tt k (1) and can calculate the value of e as follows:            3322211131 2 tdtdttds 2 1 tder2πtterπiv (2) the experimental results for the thermal conductivity comparison with the equations or models of thermal conductivity developed by researchers such as hamilton and crosser model [19], timo feeva et al model[20], wesley charles – williams' model[21], yu and choi model[22]. the hamilton and crosser is the closest to practical by difference does not exceed 3. 27%. 4. results and discussion the measured values of the density agrees well with the figures from mixing theory [14] as shown in figs.(9 and 10). also show at the density of ethylene glycol – based cu ,al and zr2o3 are increased with increasing concentration . the density of cu/eg is greater than zr2o3/eg and al/eg due to the high density and small particle size for cu. figs.(11, 12 and 13) show that the dynamic viscosity of ethylene glycol – based cu ,al and zr2o3 are increased about 2.3 % for 0.25vol% at 25c 0 compared with that of eg. the viscosity for eg/ zr2o3 is greater than eg/al and eg/al2o3 due to large particle size for zr2o3 (50nm) as show in fig.(14). figs.(15, 16 and 17) reveal the small difference between the experimental results and two models may arouse from the surface and size effects on the specific heat capacity of nanoparticle [13], and hence, decreased with increasing,due to agglomeration of nanofluid (clustering). we adopt model i and ii respectively to show the nanoparticle size effect on the specific heat capacity of nanofluid, as shown in fig.18. the specific heat capacities of nanoparticles correspond to the bulk cu (25 nm), al(30nm) and zr2o3 (50nm) respectively [13]. as shown the specific heat capacity of nanofluid is underestimated using the specific heat capacity of bulk cu, al and zr2o3. while the prediction can be improved with the specific heat capacity of cu (25 nm), al (30 nm) and zr2o3 (50nm) nanoparticle obtained from either theoretical analysis or experiments. the results from our previous calculation show that the discrepancy between nanoparticles with different sizes is small when increasing the nanoparticle volume concentration due to the large specific heat capacity of base fluid. qualitatively the solid – liquid interface may change the phonon vibration mode near the surface area of a nanoparticle and thus change the specific heat capacity of nanofluid. the high specific interfacial area of nanoparticle can adsorb liquid molecules to its surface and form liquid layers which will reversely constrain nanoparticle and turns its free – boundary surface atoms to be non – free interior atoms [13]. the varied gibbs free energy of nanoparticle and liquid layers will further change the specific heat capacity of nanofluid. fig.18. shows that the specific heat capacity for al/eg is greater than zr2o3 and cu due to nanoparticle size. the results indicates that the specific heat capacity of cu (25 nm), al (30 nm) and zr2o3 (50nm) nanofluid decreases gradually with increasing volume concentration of nanoparticles. figs.(19–22) shows the dependence of thermal conductivity enhancement on the particle volume fraction for cu/ eg, al/eg and zr2o3/eg nanofluids. the thermal conductivity enhancement is calculated from the following formula: al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 32 1)x100 k k ((%)t enhancementy conductivi thermal b nf  results show that the thermal conductivity enhancement increases with the volume fraction of cu (25 nm), al (30nm) and zr2o3 (50nm) nanoparticles (see figs 19,20, 21 and 22) and the hamilton and crosser is the closest to practical difference does not exceed 3.27 %. the highest thermal conductivity enhancement observed in the current experiment is 30 %, 17 % and 4.5% at a particle volume fraction of 2.5% for cu / eg, al/eg and zr2o3/ eg nanofluids respectively. the thermal conductivity enhancement for cu /eg is greater than al/ eg and zr2o3/eg nano fluids due to small nanoparticle size for cu as shown in fig .22. the figs (23, 24, and 25) represent shear stress versus shear rate for three series of nanofluid in various concentrations. it can be found that there is almost linear relation between shear stress and shear rate for all concentrations of nanofluids which confirm a newtonian behavior for cu / eg, al/eg and zr2o3 / eg in volume fraction 0.25 and 2.5 vol %. it is found that the addition of nano particles increase the wall shear stress. figs (26, 27, 28 and 29) represent the ratios of density, viscosity, specific heat and thermal conductivity to the base fluid ethylene glycol – based cu / eg, al/eg and zr2o3 / eg. the results show that the cu /dw, al/dw and zr2o3/dw nanofluids gives higher thermal properties, heat transfer enhancement and shear stress rise than the cu / eg, al/eg and zr2o3 / eg nanofluid . 5. conclusion 1. it was found that the addition of nanoparticles increases both the thermal conductivity and wall shear stress. 2. the shear stress and shear rate of cu, al and zr2o3 nanofluid have shown a linear relationship and the nanofluid exhibited newtonian behavior. 3. the nanoparticle volume concentration has considerable influence on the viscosity of cu, al and zr2o3 nanofluid. the nano fluid with higher particle concentrations exhibited more viscosity. 4. the viscosity of nanofluid for the base of ethylene glycol or distilled water increases when the volume concentration of nanoparticles increases. 5. the effect of nanoparticle size and nanoparticle – liquid interface on the specific heat capacity of nanofluid. 6. the effect of liquid adsorption on suspended nanoparticle's surface will also increase the specific heat capacity of nanofluid to some extent with increasing nanoparticle's volume concentration, which may be worthy be investigated further for nanofluid. 7. the results show that nanofluids eg based (cu, al and zr2o3) gives better density and viscosity than distilled water ,while on reversal for thermal conductivity and specific heat be better for distilled water than ethylene glycol 6. reference [1] y.m. xuan, q. li, w.f. hu, aggregation structure and thermal conductivity of nanofluid, aiche j. 49 (2003) 1038. [2] s. kabelac, j.f. kuhnke, annals of the assembly for international heat transfer conference, 2006, p. 13, kn-11. [3] s. lee, s.u.s. choi, s. li, j.a. eastman, measuring thermal conductivity of fluids containing oxide nano particles, j. heat transfer 121 (1999) 280. [4] j.a. eastman, s.u.s. choi, s. li, l.j. thompson, proc. symp. nano phase nano comp. materials, 1997, pp. 3–11, ii. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 33 [5] h. masuda, a. ebata, k. teramae, n. hishinuma, alteration of thermal conductivity and viscosity of liquid by dispersing ultra-fine particles (dispersions of λ – al2o3,sio2 and tio2 ultra-fine particles), netsu bussei 4 (1993) 227–233. [6] s.h. kim, s.r. choi, d.s. kim, thermal conductivity of metal-oxide nano fluids: particle size dependence and effect of laser irradiation. asme j. heat transfer 129(2007) 298. [7] c.h. chon, k.d. kihm, s.p. lee, s.u.s. choi, empirical correlation finding the role of temperature and particle size for nano fluid (al2o3) thermal conductivity enhancement, appl. phys. lett. 87 (2005) 153107. [8] h.q. xie, j.c. wang, t.g. xi, y. liu, f. ai, q.r. wu, thermal conductivity enhancement of suspensions containing nano sized alumina particles, j. appl. phys. 91 (2002) 4568. [9] t.k. hong, h.s. yang, c.j. choi, study of the enhanced thermal conductivity of fe nano fluid, j. appl. phys. 97 (2005) 064311. [10] eastman ja, choi sus, li s et al (2001) anomalously increased effective thermal conductivities of ethylene glycol-based nano fluids containing copper nano particles. appl phys lett 78:718–720 [11] a. einstein, 1956. investigation on the theory of brownian motion", dover, new york, .pp.1 – 18. [12] h.c.brinkman, 1952. the viscosity of concentrated suspensions and solution". chem.phys .20571. [13] b.-x. wang, l.-p. zhou, and x.-f. peng, “surface and size effects on the specific heat capacity of nanoparticles,” international journal of thermophysics, vol. 27, no. 1, pp. 139– 151, 2006 [14] g.k.batchelor, 1977. the effect of brownian motion on the bulk stress in a suspension of spherical particles". j.fluid mech.83 (1) 97. [15] ashrae handbook 1985 fundamentals, american society of heating, refrigerating and air-conditioning engineers inc., atlanta, 1985. [16] b. pak, y. cho,1998. hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles", experimental heat transfer 11 (2) 151–170. [17] xuan, y. and w. roetzel, 2000. conceptions for heat transfer correlation of nanofluids, international journal of heat and mass transfer, 43: 3701-3707. [18] murthy bsr, dr.a.ram krisnna and rama krisnnab.v.2004.thermally analysis of epoxy based fiber reinforced" ie (i) journal –mc, vol.84. [19] rondeauz f, ph., bready j.m.rey.2001. thermal conductivity measurement of epoxy system at low temperature" cryogen tic engineering conference (cfc). usa. [20] hamilton, r.l. and o.k. crosser, 1962. thermal conductivity of heterogeneous 2 – component systems.& engineering chemistry fundamentals, 1962.1(3): p. 187.124. [21] timo feeva, e.v., a.n. gavrilov, j.m. et al,.2007.thermal conductivity and particle agglomeration in alumina nano fluids experimental and theory". physical review e,.76(6):p.16. [22] wesley charles williams, 2006.experimental and theoretical investigation of transport phenomena in nano particle colloids (nano fluids)", department of nuclear science and engineer at massachusetts institute of technology. [23] yu, w. and s.u.s. choi, 2003. the role of interfacial layers in the enhanced thermal conductivity of nano fluids: a renovated maxwell model". journal of nano particle research, 5(1-2): p. 167 – 171. http://dx.doi.org/10.1007/s10765-006-0022-9 http://dx.doi.org/10.1007/s10765-006-0022-9 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 34 figure(2): digital viscometer model dv – e figure(3): comparison of ashrae viscosity values of 60:40 ethylene glycol and water mixture (by weight) and experimental data, 1cp (centipoises) =1mpas. figure(4): specific heat apparatus (esd 201) temperatu re c 0 v is co si ty c p al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 35 figure(5): thermal conductivity figure(6): nanofluid dish al / eg apparatus , al2o3 / eg and cuo /eg figure (7):sample disc used figure(8): schematic diagram for lee's in the experiments disc method 1 s 2 h 3 a.c t1 t2 t3 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 36 figure(9):density of eg + based cu, zr2o3 and al figure(10): density ratio of eg + based figure(11):viscosity ratio of eg + based cu cu, zr2o3 and al ρ k g /m 3 ø (%) ρ k g /m 3 n a n o /ρ b a se ρ ø (%) ø (%) μ n a n o /μ b a se al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 37 figure(12):viscosity ratio of eg figutr(13):viscosity ratio of eg + based zr2o3 + based al figure(14): viscosity ratio of e g + based figure(15): comparison of specific heat correlation zr2o3, al, cu with two model for cu+ e μ n a n o /μ b a se (% ) ø c p n a n o /c p b a se (%)ø μ n a n o /μ b a se (% ) ø (%)ø μ n a n o /μ b a se al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 38 figure(16): comparison of specific heat correlation figure(17): comparison of specific heat correlation with two model for zr2o3+ eg with two model for al + eg figure(18): specific heat ratio of eg figure(19):thermal conductivity ratio of + based al, cu and zr2o3 eg + based cu c p n a n o /c p b a se (%)ø (% )ø c p n a n o /c p b a se c p n a n o /c p b a se (%) ø k n a n o /k b a se (%)ø al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 39 figure(20):thermal conductivity ratio of figure(21):thermal conductivity ratio of eg + based zr2o3 eg + based al figure(22): thermal conductivity ratio of figure(23): shear stress versus shear rate for eg + based cu, zr2o3 and al eg + based cu k n a n o /k b a se (%)ø k n a n o /k b a se (%)ø (%)ø k n a n o /k b a se al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 40 (%)ø figure(24): shear stress versus shear rate for figure(25): shear stress versus shear rate for eg + based zr2o3 eg + based al figure(26): density ratio of eg figure(27): viscosity ratio of e g and dw + based cu, zr2o3 and al and dw + based cu, zr2o3 and al figure(28): specific heat ratio of eg figure(29): thermal conductivity ratio of e g and dw + based al cu and zr2o3 and dw+ based cu ,al and zr2o3 k n a n o /k b a se (%)ø (%)ø μ n a n o /μ b a se c p n a n o /c p b a se n a n o /ρ b a se ρ (%)ø (%)ø template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 259 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. investigation on the mechanical and metallurgical properties of the brazed aluminum joints using different al-si filler alloys and clearance approaching baha s. mahdi u.o.t.production engineering and metallurgy dept. baghdad, iraq email: bahasami1973@gmail.com neam fawzi mohammed, msc engineer, u.o.t.production engineering and metallurgy dept. baghdad, iraq email: neam_alasady@yahoo.com received on 27 october 2016 accepted on 9 august 2017 abstract: the aim of this work is to study the effect of filler metal alloy, on the metallurgical aspects of diffusion rate and mechanical properties of the brazing joint using two types of silicon-aluminum filler metal alloys on the commercially aluminum base metal. the brazing process experiments done by joining al-alloys (1100) type by a brazing process using (alsi5,alsi12) filler metals at 600-650 o c. two types of joint were made, inclined and curvature design. to indicate the brazing joint performance the specimens tested for single shear tensile test and metallurgical testing using optical and scanning electron microscope attached with energy dispersive detector. diffusion rate results according to joint clearance and brazing time accomplished using optical microscope images for joints cross sections and data gained with assisting of imagej ® software. the joint sections analyzed using eds detector and x-ray analysis to observe the produced phases. the major phases of brazed joints using 12%si filler alloy gives (al, fe3si, al 0.3fe3si0.7) and (al 0.3fe3si0.7) for the 5%si filler alloy. the two filler alloys (5 and 12%si) had equivalent tensile strength with respect to the base metal (al-1100 alloy) of 176 and 128mpa respectively, therefore the maximum joint efficiencies are 170% for al5%si filler alloy and 123% for al12%si filler alloy which mean that the tensile strength of the brazed joint had values greater than 100%. keywords: aluminum brazing, eutectic aluminum filler metals, furnace brazing. 1introduction the brazing refers to the joining process of heating a joint to the liquidus temperature of the used filler metal over 450 o c. the american welding society describes the brazing filler metal as the additional metal when producing a braze. brazing filler metal is metal or else alloys that must have a melting temperatures mailto:bahasami1973@gmail.com mailto:neam_alasady@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 260 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. above (450°c) but under those of the metals to be joined. this clearly established the term “brazing filler metal” has replaced some of the terms formerly used, such as silver solder, hard solder, gold, solder, and brazing alloy [1] [2]. an aluminum-silicon brazing filler metals have been used for making brazed assemblies that can be generally exposed to nonstop provision temperatures up and around to 150°c. minor-period operative temperatures at 205°c may be allowable, dependent on the operational environment. however, brazing alloys or welding rods containing 10-13% silicon cannot readily be made other than as extruded or cast rods due to their poor working properties at normal temperatures. greater ductility and ease of fabrication are obtainable, though with higher melting point, by materials containing 5% or 7.5% of silicon, with 1% of zinc sometimes being added [3]. the aim of this work is to evaluate the best and optimum filler metals as clearance joint to give a highquality joint according to mechanical properties with changing the clearance between adjacent base metal surfaces by two different filler metals with different silicon content. also show the effect of the brazing time effect on the brazing joint strength. finally study the microstructure cross section and morphology of the fractured surface in joint after shear tensile test. 2. experimental work 2-1 materials used for metallurgical analysis, inclined and cylindrical joints are used, where all base metals used is a commercially pure aluminum (1100) with a chemical composition showed in table (1) as tested in central organization for standardization and quality control. two types of aluminum-silicon filler metals selected, (al5%si) or called e4043 supplied from harris product group used as a rod with 3.2mm in diameter and the (al12%si) was sampled from casted alloy to strips with 2x3mm cross sections. table (1): base and filler metal aluminum alloys used in the study. alloy type chemical composition% si fe cu mn mg zn cr ni al al-1100 0.182 0.619 0.034 0.01 0.007 0.001 0.003 0.003 rem al+5%si 5.00 0.20 0.00 0.02 0.00 0.05 0.00 0.00 rem al+12%si 11.63 0.872 0.88 0.24 0.153 0.51 0.013 0.03 rem 2-2 brazing process inclined specimen designed to make the clearance various by using two types' fillers metals with its length to facilities microstructure examination along different clearances values at the same test, while the cylindrical design useful to indicate large clearance effect and the maximum distance that filler metal can wet. figure (1) showed a represented design for the joints combined of two parts, a rectangular aluminum plates with dimensions of (30x30x5 and 15x30x5mm) for inclined joint and (15x30x5 and sectioned part of a cylindrical shaft of 50mm in diameter and 5mm in thickness. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 261 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (1): design of inclined and cylindrical specimens of variable clearance. 2-3 flux used the flux used was [al-braze ec. 1070] product from harris company with a chemical composition explained in table (2). the flux used is compounds of fluorides and chlorides salt mixtures as shown in table (2). adding flux to joint was done by mixing it with water as a paste then drops a small quantity gently beside the joint clearance. after covering the joint by the flux paste, the filler alloy rod placed parallel and attached to the joint. table (2): composition and information on ingredients of al-brazing of the 1070 flux. components w% lithium chloride major content zinc fluoride < 5 potassium fluoro aluminate < 4 zinc chloride < 0.01 composition comments all concentrations are in percentage, by weight unless the ingredient is a gas. gas concentrations are in volume percentage. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 262 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. after completing the flux and filler preparing on joint the assembly placed gently inside the vertical furnace chamber as shown in figure (2), and the cover is closed. figure (2): assembles specimens during brazing cycle in vertical furnace. the furnace temperature set to 100 o c for 10 minutes to evaporate the water from flux slowly preventing boiling and then it was set to 650 o c for 5%si filler and 600 o c for 12%si filler. the two-brazing temperature is founded by projection of silicon concentration in phase equilibrium diagram shown in figure (14) also the brazing temperature founded experimentally by watching the process periodically until the filler is melted during brazing process to avoid base metal during process, where the 5%si alloy estimated melting temperature is near to base metal melting temperature. the brazing time was varied from (30 to 120) minute. the environment in furnace during brazing cycle was air for all experiments and there is no need to use controlled atmosphere as argon or helium because the flux serves as oxide removal and cleaning. tensile shear test samples prepared as lap joints by putting two aluminum plates (80x20x5) mm and overlapped 5mm to achieve the shear area of 100 mm 2 . the filler alloys and flux prepared in the same procedure of the microstructural varied clearance samples. after completing the brazing cycle all samples extracted from furnace and cooled by tap water to remove flux immediately while the samples hot. samples sliced normally to brazing line as shown in figure (3), then samples sliced face grinded using different emery papers of silicon carbide grades varied from (320 to200) ppi grades. polishing was performed with diamond paste of 0.3 µm grain size on a polishing wheel covered with polishing cloth. etching was done by immersion for 10 seconds in solution of 1% of hydrofluoric acid in distilled water. after etching, the specimens were washed by tap water and finally by distilled water. specimen preparations were done according to the asm metals handbook [4]. seven inclined samples were brazed; two of them by using 5%si filler alloy and the rest by using 12%si filler alloy. for shear tensile samples the 5%si filler alloy all specimens failed from the base metal section and the joint stay without failure which indicated that the joint is stronger than the base metal. table (3) represent number of experiments done with different holding time in a brazing temperature for two filler alloys. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 263 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3): brazed joints (right) cross section for cylindrical joint (left) inclined joint (down) wetting angle after inclination for tensile test joint. table (3): experiments parameters for brazing inclined samples. 2-4 thermal cycle brazing aluminum joint process was done by applying heat in an electrical furnace by using clearance (100,200,300,400) µm to inspect narrow and wide clearance effect metallurgically and mechanical proprieties of the brazed joints. thermal cycle was applied at different temperatures and diffusion time. razing temperature was 600 c for i and 650 c for 5%si and the brazing time were 30, 60, 90, 120 and 150 minutes respectively as explained in figure (4). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 264 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (4) thermal cycles for the brazed specimens. 3. results and discussion the results discuss the effect of two type filler metals and clearance on the solubility between the filler and the base metal also study the resulted microstructure for the joints, tensile shear strength, using scanning electron microscopy to determine the phases, micro-hardness and x-ray analysis of the brazed joints. the diffusion calculations idea is based on areas percentage of eutectic and solid solution phases before and after brazing process and the calculations applied on the 12%si filler metal where the filler metal microstructure is 100% eutectic structure and any decreasing in this structure across the joint meaning more diffusion between liquid filler alloy and solid base metal. after completing the brazing joint the clearance cannot measured directly because of diffusion through grain boundaries between solid base metal and liquid filler alloy. so, clearance can be founded for any location across the joint section by multiplying the sin of inclination angle by the distance from the attached points or can be called the root of the angle where the angle was (0.7638 o ) derived by dividing the maximum clearance (0.4mm) on the joint length (30mm) which represent the tangent value of this angle. 3.1. microstructural analysis to calculate the diffusion rate experimentally for joints with variable clearance and brazing time, a numerical equation of each case obtained using graphpad prism 6 software. the cross joints areas analyzed for remaining phases using imagej software's. the first filler alloy of al+12%si microstructure before brazing consist of eutectic (al-si) with a grain size about 225 µm. while the 5%si filler alloy contains a eutectic structure of silicon-aluminum percentage of 40% according to the level rule in the equilibrium transformation diagram of (al-si) [5]. the microstructure of joints obtained by optical microscope images and analyzed using imagej software by converting the images to a binary color where the program count the phases depending on the white and black pixels as it seen in figure (5) where the black areas representing the eutectic structure and the white pixels represent the solid-solution phase. analyzing by imagej software begin by converting 24bit al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 265 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. colored images to 8bit gray image then converting it to binary (black and white) image as shown in the right side of figure (5). figure (5): aoptical microstructure for the brazed joint section. bbinary color imagej® software image for diffusion rate calculations. 3.2. fractographic analysis during examination of diffusion brazing specimens of 12%si filler alloy by tensile-shear test, the fracture takes place at the aluminum-silicon interface as shown in figure (6) where the right image shows flaked separation and left image shows silicon -aluminum phases which is the dark regions of 38% of silicon content and the bright regions representing the aluminum-24%silicon-18%iron phase, the fracture mode is brittle -ductile type as shown in figure (7) where there is elongation for the flakes and finally separation occurs also there are some crack propagations as shown in figure (6). figure (6): fracture surface of the tensile-shear test specimens. right image represents sem topography and left image represents bse image showing elemental distribution. a b al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 266 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (7): fracture mode for tensile-shear test specimens of 12% si alloy. fracture analysis of brazing joints using 5%si alloy is not investigated because the failure occurs in the base metal section instead on the joint which indicates that the joint mechanical properties are greater than those of the base metal. 3.3. shear test results (tensile shear test) table (4) shows the effect of different values of brazing joint clearance on the resulting tensile shear strength for filler of 12%si and table (5) shows the effect of joint clearance on shear strength for 5%si filler metal. table (4): tensile shear results of filler alloy of 12%si at different clearance values. clearance (12%si+al ) (µm) load (n) joint area (mm 2 ) fracture shear strength (mpa) 100 8550 160 53.43 200 8860 140 63.2 300 7400 100 74.00 400 6760 140 48.28 all tensile shear specimens tested by instron tensile and compression press 1195 machine in strength of material laboratory. the tensile shear test specimens dimensions was 80x20x5 mm as showed in figure (8) and the specimens clearance adjusted using brazing foil layers made of bni2 with thickness of 50 m. this foil melting temperature is above 1000 o c and the base metal of it is the nickel used to braze stainless steel and super alloys, therefore it will not react with aluminum brazing process and maintain the distance between adjusted two aluminum specimens. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 267 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (5): tensile shear results of filler alloy of 5%si at different clearance values. clearance (5%si+al ) (µm) load (n) joint area (mm 2 ) fracture shear strength (mpa) 100 5760 100 57.6 200 10240 100 102.0 300 7320 100 73.20 400 3000 100 30.00 figure (8): dimensions of shear tensile test specimens from figure (9) and figure (10) it can have concluded that the optimum clearance values give higher strength is 300µm for filler alloy of 12%si content with shear strength of 74mpa and 200m for filler alloy of 5%si content with 102mpa. figure (9): effect of clearance on shear strength for 12% si filler metal. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 268 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. . . . . . . . . . . . (1) figure (10): effect of clearance on shear strength for 5% si filler metal to achieve joints strength compared to the brazed joints the aluminum alloy type (1100) was tested by tensile test and the resulting value was 104 mpa for the yield strength and 120mpa for the ultimate tensile strength as shown in table (6) below. the results of tensile test for the brazed joints limited to the breaking point which indicating the joint strength. table (6): tensile strength of the 1100 al brazed joint test specimens ultimate tensile (mpa) yield strength (mpa) elongation % al-alloy 1100 120 104 17.00 3.3.1. vickers hardness test micro hardness tests of all the samples achieved by micro hardness device shown in figure (11) and the applied load during the testing fixed on 500 g, with a dwell time of 5 seϲ. it has a square-base diamond pyramid indenter. the viϲkers hardness number (vh) is calculated from the following equation [1]: where: p: applied load (kg) dav: average length of diagonals (mm) hv: vickers hardness (kg /mm²) the hardness distribution along the brazed joints at temperatures of 600c for filler 12%si is shown in figure (12) and 650°c to filler 5% si shown in figure (12). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 269 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (11): digital mico-vickers ardness tester machine. figure (12) shows the micro hardness distribution along brazed joint using optical microscope denoting each hardness point with its value while figure (13) shows the projection of the hardness values on scanning electron image. the hardness of the center of the brazing joint is higher than the hardness of the base metal for each filler used but the filler of 12%si alloy gives higher hardness value than the filler 5%si alloy which indicates more brittle joint due to the high silicon content of the filler brazing alloy which produces intermetallic compounds of al-si and al-fe as mentioned in x-ray diffraction analysis. this affect the strength of the joint where the 5%si filler joint is more ductile than 12%si alloy joint. figure (12): the variation of hardness along the brazing joint of al-alloys 1100 and with filler metal of 12%si content. brazing zone al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 270 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (13): the variation of hardness along the brazing joint of alalloys 1100 with filler metal al+5%si. the joints of 5%si filler alloy cannot be analyzed by the software due to high diffusion rate and low phases of silicon concentration in joint core on the contrary of 12%si filler alloy joints. as well as the same condition applies to shear tensile test, where the 5%si filler alloy joints frailer occur in base metal instead of the joint. figure (14): point chemical analysis for 5% si filler alloy joint core with 30minute of brazing holding time at 650 o c. no. elements (wt%) al si fe cu mn 17 66.8 15.7 17.5 ---- 18 49.1 50.9 ------ 20 56.7 12.5 30.7 ---- 21 61.5 15.5 23.0 ---- al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 271 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (14) represent the microstructural analysis and point chemical analysis using sem attached with eds detector to the brazing region of 5%si filler alloy. there are two phases shown clearly. the first phase represents the points 17, 20 and 21 which located in region in figure (15) as a small blue triangle and it appear as bright needles representing the major phase and the second phase appear like dark fine needles as minor phase where its chemical composition in points 18 and 22 and when these two points projected in ternary diagram it located in diamond silicon phase. figure (15): ternary phase diagram for al-si-fe and the phases locations for the analyzed points [6]. figure (17) represent eds points analysis for the sem image for 12%si brazing filler metal. there are three main phases. points 17 and 19 represents  phase of aluminum-silicon when projected on ternary diagram shown in figure (15) where this phase shaped as needle like and the diamond silicon irregular shape phase represents in points 20 and 22. point 18 showing an aluminum 60% and copper composition which make  phase on al-cu equilibrium phase diagram in figure (16). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 272 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (16): al-cu equilibrium phase diagrams [7] no. elements (wt%) al si fe cu mn 17 56.3 17.2 24.0 --2.5 18 60.0 ----40.0 -- 19 66.6 8.8 18.2 --6.5 20 37.9 61.3 ------ 21 97.3 2.1 ------ 22 75.2 21.2 ------ figure (17): point chemical analysis for 12%si filler alloy joint core with 30minute of brazing holding time at 600 o c. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 273 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. conclusions: the following points can be concluded from the present work: 1. the two filler metals 5%si and 12%si aluminum alloys completely spread and fill the joint at the first minutes of liquation. 2. the two filler alloys 5%si and 12%si aluminum alloys had equivalent tensile strength of 176 and 128mpa respectively which is stronger than the mechanical properties of the base metal ultimate tensile strength (120 mpa). 3. the formation of (alsi ,alsife and eutectic phase) are responsible for joining process and gives the strength to the joint. 4. 5% silicon content filler metal shows better mechanical and metallurgical properties where the shear tensile strength and spreading across the joint is better than 12% silicon content filler metal. references: 1. william. d. callister, "fundemental of materials science and engineering an integrated approach", john willey& sons, (2008) 2. howar.b.,''modrenweldingtechnology'',5 th _edition,prentice,prentice_hall,2002 3. practice, philip m.roberts, ''industrial brazing'',/hardcover/ crc/press, december 2003 4. david l. olson, "welding and brazing and soldering", "metals hand book", volume six, , 9th edition. asm, 2004 5. hugh baker, "asm metals handbook, vol 03 alloy phase diagrams", page 2-52, 2004 6. martin c.j. markera, barbara skolyszewskakühbergera, ''phase equilibria and structural investigations in the system al–fe–si'', intermetallics volume 19, issue 12, pages 1919–1929, copyright elsevier b.v © 2016 7. t. b. massalski, hiroaki okamoto, ", alloy phase diagrams-binary alloy phase diagrams", asm, vol.3,2-44,1985. 8. patricia b. roy, fiona m. o’connell,'' vickers microindentation hardness testing of brazed joints in aluminum'', loyola university maryland21210, pp(1 to 20), 2013 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 463 predictive correlation for the viscosity temperature relation of some iraqi crude oils lec. husham.m.majeed ass. lec. ahmed a.ubeed, ass. lec. kassim k.hameed hmmt_2005@yahoo.com alshibly83@yahoo.com k_alshemary@yahoo.com chem. eng. dept., college of engineering, al-qadisiyah university. received 2 jun 2015 accepted 27 august 2015 abstract: the viscosity at different temperature are measured for some iraqi wells, a mathematical model was proposed to describe the viscosity as a function of temperature depending on the experimental results , all the samples were collected from storage tanks of the following sites: south of al rumeela, north of al rumeela, al halfaya and bozorgan. the results give good agreement with the experimental result that was measured for iraqi wells, where the maximum average percentage of error was 7.4 % , the maximum aad% was 4.4% and the maximum sd was 0.49013%. key words: viscosity, temperature, predictive correlation, iraqi crude oil, polyfit. زوجة ودرجة الحرارة لبعض النفط الخام العراقيلتنبأ عالقة تربط بين ال . هشام محمد مجيد م.م. أحمد عباس عبيد م.م.قاسم كاظم حميدم القادسية / كلية الهندسة / قسم الهندسة الكيمياويةجامعة الخالصة: كدالة ح نموذج رياضي لوصف اللزوجةااقترحيث تم بعض اآلبار العراقية،لنفط مختلفة يةاللزوجة في درجة حرار مقدار تم قياس الرميلة، من المواقع التالية: جنوبالنفط الخام العراقي و من خزانات النماذجتم جمع اذ على النتائج التجريبية لدرجة الحرارة باالعتماد التجريبية التي تم قياسها لآلبار العراقية وكان الحد النتائججيد مع المحسوبة توافقالنتائج شمال الرميلة، الحلفاية و بزركان. اظهرت 0. %49013اما الخطأ المعياري فكان مقدارة %4.4اعظم مقدارلالنحراف المطلق فكان و% 7.4هو النسبي لخطألمعدل ا األقصى introduction: the viscosity is one of the important crude oil properties, therefore it is important to understand the viscosity behavior of crude petroleum and used it in the different engineering applications such as the calculation of total power requirement for pumping the crude oil, studying the energy loses during production, transportation through pipelines, and reservoir simulations as well as in determining the structure of liquids 1 . mailto:hmmt_2005@yahoo.com mailto:alshibly83@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 464 the viscosity is a function to some parameters such as the temperature, pressure, composition of the crude oil….etc. but the viscosity of one type of a crude oil is a strong function of temperature only, which is the most important variable during the pumping requirements, especially; the temperature could be varied during the processing of the oil. generally the relation generally between temperature and viscosity of the crude oil is an inverse relationship, and the prediction of this relation in form of formula to relate these two variables has received great attention from engineers in the field of the oil refineries especially for design of equipments, and pipelines. the old procedure to calculate the viscosity of the oil is accomplished by using the generalized reduced viscosities chart 17 , where this is not direct method because the critical viscosity µc must be determined before using this chart. there is another method is used to calculate the viscosity at different temperature depending on the astm chart method but it also has a basic disadvantage where the extrapolation is required. therefore many viscositytemperature equations have been proposed to predict the relation between the temperature and the viscosity to solve this problem and predict a suitable equation between the viscosity and the temperature. the first study were began in 1946 by beal 4 , after some years in 1972 velzen et al. proposed a simple method to estimate the viscosity value 1 , after that some researchers tried to find an accurate relation such as (amin and maddox 3 ; ely and hanley 7 ; beg et al 14 ; and al-besharah 2 ) but the main shortcoming in all these predictive correlations is the error which is present as a result to the deviation between the theoretical and experimental data. also all these correlations have some coefficients that must be determined from the available crude oil data. in 1993 puttagunta et al. 12 have been successful proposed a good model to describe the relation between the viscosity of the american crude oil with temperature which gave a small deviation. this model was tested for different crude sources such as nigerian crude oil 1 and also gave good and suitable results for predicting effect of temperature on kinematic viscosity. the viscosity of middle-east crude oil was modeled by singh et al 15 . they modified their model where it gave overall average absolute deviation less than 5 %. other predicted studies were developed to correlate the viscosity with temperature such as ghetto et al. 6 ; petrosky and farshad 11 ; wakabayashi 18 ; bennison 5 ; miadonye and puttagunta 9 ) and also these correlation has a significant errors. jabir shanshool was developed a new correlation between the kinematic viscosity and temperature in 2001 8 . he based on experimental kinematic viscosity data for twenty tbp fractions of arab heavy, arab medium and arab light and arab extra-light crude oils. his correlation gave average absolute deviation of 7.2% the viscosity of iranian crude oil in 2013 was predicted by using artificial neural network using matlab program environment depending on 75 samples 10 . the viscosity of iraq crude oil was predicted by rwaida kaiser abdulmajeed 13 in 2014 according to an experimental data collected from different samples of iraqi oil reservoirs ,she develop a new correlation to calculate the oil viscosity at various temperature, her study gave (1.72 %) standard deviation error compared with the other correlations. in this work, a simple correlation has been developed to calculate the viscosity of crude oil with temperature using 40 samples collected from different iraqi wells. the samples were collected from al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 465 storage tanks of the following sites: south of al rumeela, north of al rumeela, al halfaya and bozorgan. experimental work the samples of crude oil from different wells were collected, from storage tanks of the following sites: south of al rumeela, north of al rumeela, al halfaya and bozorgan. these samples were used for measuring the viscosity experimentally with different temperatures. a 100 ml of each crude oil sample was added into a beaker. the beaker was putted inside the digital heating mantle; the mantle must be maintained to the desired temperature before heating the sample by setting the temperature to a desired point. the temperature was recorded depending on the thermometer reading. the viscosity was measured by viscometer apparatus during heating (as shown in figure 1), where the wheel of the apparatus was immersed in the beaker at each measuring point. this process is repeated for the various crude oils and at different temperature. the temperatures range was 20 to 60 o c. simulation of viscosity a new model was predicted by using matlab simulation program depended on the data which measured for these sites. we develop the following function of the viscosity-temperature correlation as follow: --------------------------------------------------------------- (1) where; is the kinematic viscosity in centistoke (cst.) b, m: are constants t is the temperature in o c. results and discussion: the comparative viscosity-temperature variation of the experimental and the predictive results (from matlab simulation) for some iraqi crudes oil are presented in tables (1) and (2). the relation gave a good agreement between the predictive and measured viscosity with error (average percentage of error (equation 2)) of 7.4 % the predictive model parameters (b& m) are calculated using polynomial curve fitting (polyfit) function and shown in table (3). in order to verify the correctness of our predictive correlation the average percentage of error was calculated for each of the viscosity and compared with experimental values according to the equation ( 2) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 466 | | ---------------------------------------(2) the average absolute deviation (aad) was calculated as follow: ( ⁄ ) ∑ |( )| --------------------------------(3) where the overall average absolute deviation for the entire data aad % are shown in table (4). the maximum aad% was 4.4% for bozorgan crude oil. the smallest average absolute deviation was found to be 2.37% for south of al rumeela crude oil samples. it was illustrated as shown in table (1) and (2) that the error values does not depend on the increasing or decreasing of the temperature nor on the type of crudes, where the relationship was tended to increases and decreases for each of the crude oil samples. it is evident generally that as temperature increases the experimental and predictive viscosities are decreases of each oil, also it can be explained that the relationship as shown in the equation (1) does not represent reality the relationship between viscosity and temperature, but rather represent the closest relationship to reality which gives the lowest value of the error calculated by equation (2). the values of experimental and predicted viscosities al halfaya, north of al rumeela, south of al rumeela and bozorgan crude oils as function of temperature are plotted in figure 2, 3, 5 and 5 respectively. each figure illustrates a comparison between the predicted and experimental viscosities of the iraqi crude oil for 10 data points of these wells. the reliability of the proposed model with the parameters was evaluated by the average absolute deviation aad% (see equation (3)). the maximum aad% was 4.4% in the bozorgan crude oil as shown in the table (4). comparison the proposed model with different models it is worth mentioning that there are no previous studies to estimate the viscosity correlation for iraqi crude oil except the predictive equation which was adopted by rwaida kaiser abdulmajeed 13 . she wasn’t depending on the average percentage of error as described in equation (2). she was examined their proposed equation by using the standard deviation error (sd), as shown in equation (4) below: √( ∑ | | ) ------ --------------------------------------((4) her model gave 1.72% sd, therefore in order to compare our model with her equation we must calculate the standard deviation error for our model. the standard deviation error (sd) was calculated for our model shown below in table (5): we can say that our model gave more accurate result for comparison between the experimental and predictive data according to the result shown in table (5), where the maximum sd was 0.49013 for bozorgan crude oil. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 467 conclusion a simple and new kinematic viscosity-temperature correlation has been developed for south of al rumeela, north of al rumeela, al halfaya and bozorgan crude oil. the experimental results of viscosity with temperature represent nonlinear relation as shown in table (1) and (2). the results showed that the proposed correlation gives a good agreement between the experimental and predictive viscosity, where this relation (which was represented by equation (1)) was found to be the most suitable for the prediction of viscosity, where it gives an (0.49013%) standard deviation error compared with the other correlations which give (1.72 %) standard deviation error. therefore it could be concluded that the present correlation can be considered an accurate correlation to predict viscosity with temperature of the iraqi crude oils. nomenclature aad average absolute deviation b, m constants cp centipoise polyfit polynomial curve fitting function in matlab program sd standard deviation error t the temperature in o c. the kinematic viscosity in centistoke (cst.) µexpr experimental kinematic viscosity centipoise µpred predictive kinematic viscosity centipoise references [1] a.s. abdulkareem and a. s. kovo (simulation of the viscosity of different nigerian crude oil) , leonardo journal of sciences . issue 8, january-june 2006 , p. 7-12 [2] a1-besharah, j. m., akashah, s. a., mumford, c. j.: (the effect of temperature and pressure on the viscosities of crude oils and their mixtures). ind. eng. chem. res. 28, 213-221 (1989). [3] amin, n.b. and r.n. maddox. (estimating viscosity versus temperature). hydrocarbon process. 59(12) (1980) 131. [4] andrade, e.n. da c., philosophical magazine., 17 (1934) 497; ibid, 17 (1934) 698. [5] bennison, t. 1998. (prediction of heavy oil viscosity. presented at the ibc heavy oil field) development conference, london, england, 2–4 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 468 [6] de ghetto, g., paone, f., and villa, m. 1995. pressure-volume-temperature correlations for heavy and extra heavy oils. presented at the spe international heavy oil symposium, calgary, alberta, 19–21 june. spe-30316-ms. http://dx.doi.org/10.2118/30316-ms.december. [7] ely, j.f. and h.j.m. hanley. (prediction of transport properties. 1. viscosity of fluids and mixtures), ind. eng. chem. fund., 20 (1981a) 323. http://dx.doi.org/10.1016/s0016-2361(97)00090-2. http://dx.doi.org/10.1080/10916469808949803. http://www.pe.tamu.edu/barrufet/public_html/pete310/ papers/visco%20models.pdf. [8] jabir shanshool and emad talib hashim ( kinematic viscosity-temperature correlation for undefined petroleum fraction of a wide boiling. petroleum science and technology. , 19(3&4), 257– 268 (2001). [9] miadonye, a. and puttagunta, v.r. 1998. modeling the viscosity-temperature relationship of nigerian niger-delta crude petroleum. petroleum science and technology 16 (5 & 6): 627–638. [10] mohmammed soleimani lashkenari,majid taghizadeh and bahman mehdizadeh. (viscosity prediction in selected iranian light oil reservoirs: artifical neural network versus empirical correlations), pet.sci.(2013) 10 :126-133. [11] petrosky, g.e. and farshad, f.f. 1995. viscosity correlations for gulf of mexico crude oils. presented at the spe production operations, [12] puttagunta, v.r., miadonye, a., and singh, b. 1992. (viscosity temperature correlation for prediction of kinematic viscosity of conventional crude). trans. inst. chem. eng. 70: 627–631. [13] rwaida kaiser abdulmajeed . (new viscosity correlation for different iraqi oil fields). iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 71-76 [14] s.a. beg, m.b. amin and i. hussain, "generalized kinematic viscosity temperature correlation for undefined petroleum fractions", the chemical engineering journal, 38, 123-136, 1987. [15] singh, miadonye and puttaguntat (modeling the viscosity of middle-east crude oil mixtures), ind. eng. chem. res. 1993,32, 2183-2186. symposium, oklahoma city, oklahoma, 2–4 april. spe-29468 ms.http://dx.doi.org/10.2118/29468-ms. [16] van velzen, d., r.l. cardozo and h. langenkamp. (a liquid viscosity-temperature-chemical constitution relation for organic compounds). ind. eng. chem. fundam., 11 (1972) 20. [17] w. l nelson, (petroleum refinery engineering), mcgraw-hill book company, inc., new york, 4th edition 1958. [18] wakabayashi, t. 1997. viscosity correlation with specific gravity and molecular weight of crude oil fractions. fuel 76 (11): 1049–1056. http://dx.doi.org/10.2118/30316-ms.december al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 469 15 15 table (1): temperature versus viscosity data for al halfaya, bozorgan t o c al halfaya bozorgan µexpr centipoise(cp) µpred cp %error equation (2) µexpr. cp µpred cp %error equation (2) 11 180 165.8307 7.871833 59 57.1461 3.142203 20 136.65 134.4202 1.63176 48.15 47.8804 0.559917 25 109 108.9593 0.037339 44 40.117 8.825 30 85 88.321 3.90706 32 33.6124 5.03875 35 67.5 71.5919 6.06207 26.27 28.1625 7.20404 40 54.8 58.0314 5.89672 22.14 23.5962 6.57724 45 45 47.0395 4.53222 19.1 19.7703 3.50942 50 37.8 38.1296 -0.87196 16.5 16.5647 -0.39212 55 31.9 30.9074 3.111599 14.3 13.8789 2.944755 60 27.06 25.0531 7.416482 12.36 11.6285 5.918285 table (2): temperature versus viscosity data for south of al rumeela, north of al rumeela. t o c south of al rumeela north of al rumeela µexpr centipoise(cp) µpred cp %error equation (2) µexpr cp µpred cp %error equation (2) 15 11.45 11.1755 2.39738 17 16.3122 4.045882 20 10.36 9.9706 3.758687 14.8 14.357 2.993243 25 8.78 8.8956 1.31663 12.62 12.6362 0.12837 30 7.81 7.9364 1.61844 10.7 11.1217 3.94112 35 6.8 7.0807 4.12794 9.45 9.7887 3.58413 40 6.225 6.3173 1.48273 8.35 8.6154 3.17844 45 5.52 5.6362 2.10507 7.33 7.5828 3.44884 50 4.96 5.0285 1.38105 6.7 6.6739 0.389552 55 4.55 4.4863 1.4 6 5.874 2.1 60 4.175 4.0026 4.129341 5.4 5.17 4.259259 table (3): parameters value of the predictive equation. well parameters b m al halfaya 311.3621 -0.0420 bozorgan 97.1570 -0.0354 south of al rumeela 15.7366 -0.0228 north of al rumeela 23.9251 -0.0255 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 470 table (4): average absolute deviation values. well aad% al halfaya 4.133904 bozorgan 4.411173 south of al rumeela 2.371727 north of al rumeela 2.806884 table (5): the standard deviation error values (sd). well sd % al halfaya 0.459323 bozorgan 0.49013 south of al rumeela 0.263525 north of al rumeela 0.311876 figure (1): brookfield digital viscometer model dv-e in the lab. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 471 figure (2): al-halfaya temperature viscosity relation figure (3): al-north of al-rumeela temperature viscosity relation al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 472 figure (4): al-south of al-rumeela temperature viscosity relation figure (5): bozorgan temperature viscosity relation al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 139 fabrication of mo nanorods on silicon wafer using glancing angle deposition technique. dr.mohammed d. salman, dr. mushtaq i. hasan, l.haider j. abid. mech. eng. dept., college of engineering, thi-qar university. mohammed_selman2000@yahoo.com, mohal@gmail.com abstract array of silicon nanorods with a circular cross section onto mo nanopillars arrangement were grown using glancing angle deposition (glad) on si (100).deposition technique was used to fabricate mo thin film on silicon flat surface. teflon deposited on the tips of mo nanorods at normal incident evaporation (θdep.is 0 o c) with deposition time of (5 min.) to study the hydrophoposity and hydroplilicity of the surface. morphology of mo and mo/teflon nanocomposite was carried out using scanning electron microscope (sem) which indicates a (100 nm) of mo thin film and mo nanorods on silicon substrate. contact angle measurement on nanocomposite mo nanorods with teflon grown on their tips exhibited contact angle values as high as (116 o ) indicating an increase in the hydrophopocity of original hydrophilic mo nanostructures that had an angle of (40 o ). key words: nanorods, molybdenum, teflon, glad. وم النانوية على رقائق السليكون باستخدامنيبديتصنيع قضبان المول تقنية الترسيب الزاوي الخاطف. د.محمد دخيل سلمان ، د. مشتاق اسماعيل حسن ، م. حيدر جبار عبد قسم الهندسة الميكانية / كلية الهندسة/ جامعة ذي قار الخالصة وم بدينيالمولمن اعمدة دائرية شريحة من خالل ترسيبالنانوي بالمستوى السليكون اسطح من تم تحضير مجموعة استخدمت تقنية الترسيب االعتيادي لصنع طبقة رقيقة من الموليبيديوم على (. gladتقنية ) باستخدام النانوية على تلك االسطح مساوية اعتيادية تبخربزاوية النانوية والتي سقطت الموليبيديوم على اطراف اعمدة رسب التفلون .المسطحة السيليكون اسطح اسطح الموليبيديوم و مورفولوجيةلدراسة اسطح السليكون الكارهة والمحبة للماء. .( دقائق5)وبزمن صفر لدرجةل قيقة من كطبقة ر نانومتر (100) اشار إلى وجودوالذي المجهر االلكتروني الماسح باستخدام دراستهاالموليبيديوم/تيفلون تمت يوميندبالمولاعمدة قياس زاوية االتصال بين قطرة الماء و .السيليكون اسطح علىالنانوية يوميندبالموليوم و كذلك اعمدة يندبالمول ( درجة مظهرة اسطح نانوية كارهة للماء مقارنة 111النانوية المغطية بطبقة التفلون على نهاياتها اظهرت زاوية عالية تصل الى ) ( درجة.04دون التيفلون المحبة للماء بزاوية )مع االسطح النانوية ب mailto:mohammed_selman2000@yahoo.com mailto:mohal@gmail.com al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 140 1. introduction: in recent years, silicon nanorays have received considerable attention due to their unique properties and potential application in silicon based optoelectronic devices. various patterning techniques have been employed to grow periodic nanostructures including colloidal self-assembly , e-beam lithography and laser interference lithography (patzig, 2008). while the former is cost effective but limited to hexagonal close packing with a high packing density, the latter two techniques are capable of creating regular sub-100-nm patterns with various lattice geometries, but are limited by low processing speed, high cost, and incompatibility with large-area processing (gish 2008). glancing angle deposition (glad) technique is a physical vapor deposition method to design three-dimensional nanostructures by programming the vapor incident angle and substrate azimuthal rotation. this method offers large area growth of aligned nanorod arrays with additional capability of self-alignment. there is almost no limitation on materials that can be fabricated into desired nanostructures. with recent advance in a multilayer deposition procedure, one can design complex and multifunctional heterogeneous nanostructures. glancing angle deposition (glad), developed by robbie and brett exploits atomic shadowing effects during physical vapor deposition to create nanostructures with a wide range of engineering shapes including nanopillars, zigzags, nanospirals, and y shapes (zhoj,2007) with potential applications as photonic crystals, sensors, catalyst supports, magnetic storage media, and field emitters (nang,2007). glad on flat substrates involves a stochastic nucleation process, yielding films consisting of randomly distributed nanorods. in contrast, periodic arrays are achieved by substrate patterning prior to deposition (li,2007 ). in the latter case, the patterned surface mounds are the nucleation sites for the nanostructures, since film growth on the surrounding substrate is suppressed by atomic shadowing, that is, the atoms of the directional deposition flux are captured by the mounds and do not reach the substrate using physical vapor deposition (pvd) (kosiorek, 2004). it is well known that films deposited by physical vapor deposition (pvd) commonly possess a columnar microstructure which affects many film properties. glancing angle deposition (glad), which capitalizes upon this fact, has been developed as a technique to engineer the columnar structure of molybdenum thin films on the nanoscale. recently there has been an increasing focus on methods to produce surfaces with a varying topography on the nanometer length scale for applications in e.g. biotechnology, photonics, and catalysis, since the nanoscale surface topography is known to influence the performance in these areas (kuo, 2003). when glancing angle deposition is combined with a continuous substrate rotation, the growth of nanostructures with various shapes such as vertical posts, spirals and screws is possible. the shape is controllable with the ratio ρ = r/ω of the deposition rate r to the rotational speed ω. besides the control of ρ, other deposition parameters such as the deposition angle β between particle flux and substrate normal, or the substrate temperature can be used to alter morphology and density of the grown sculptured thin films (kuo, 2003). controlling the wet ability of surfaces is an important problem relevant to many areas of technology; in general, the wet ability of a solid surface is governed by both the chemical state and the geometry of the morphology (boduroglu, 2007). however, to fully utilize the hydrophobic properties of nanostructure surfaces, it is necessary to study the fundamental relationship between the nanostructure and the hydrophobic behavior. once the relationship is established, new materials with desired hydrophobicity can be designed and fabricated. sputtering is a simple and useful technique for preparing thin films with a desired structure and properties (wisam, 2009). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 141 in this study, a novel glancing angle deposition (glad) technique was used to deposit mo thin film and mo nanostructures on silicon wafer. the glad technique provides a novel capability for growing 3d nanostructure arrays with interesting material properties. it is a simple, single-step process in addition, glad offers a cost and time efficient method to fabricate nanostructured arrays of almost any material in the periodic table as well as alloys and oxides. the glad technique uses the ‘shadowing effect,’ which is a ‘physical self-assembly’ process through which obliquely incident atoms/molecules can only deposit to the tops of higher surface points, such as to the tips of a nanostructured array or to the hill tops of a rough or patterned substrate. also this work was studied the contact angle of the composite structure of mo nanorods with teflon at the tips dramatically increases from hydrophilic values of uncoated nanorods to the highly hydrophobic values after coating with teflon tips. 2experimental work: the vertically aligned si nanorod array samples were prepared by glancing angle deposition method. experiments were done in nanotechnology centre/ institute of applied engineering and science in university of arkansas at little rock (ualr) in usa. the substrate was si(100) wafer cleaned by a rca-1 method (solution of deionized water /hydrogen peroxide/ammonium hydroxide with 5:1:1ratio was heated to 70 o c) for 10 min. followed by copious deionized water rinsing. a schematic of the custom-made glad experimental setup in the present study is shown in figure (1). in our experiments, normal deposition technique was used to formulate mo thin film onto a silicon substrate. a dc magnetron sputtering system was employed for the fabrication of mo nanorods on si is performed using glad technique. in all experiments, the depositions were performed on native oxide p-si (100) wafer pieces (substrate size 3×3 cm2), using a 99.99% pure pt cathode (diameter about 7.6 cm). the substrates were mounted on a sample holder located at a distance of about 18 cm from the cathode.. they were tilted so that the angle between the surface normal of the target and the surface normal of the substrate was about (θdep = 87◦).for the normal incidence (θdep = 0◦),the substrates were rotated around the surface normal with a speed of 2 rpm. the base pressure of about 1.5 × 10−6 torr was achieved using a turbo-molecular pump backed by a mechanical pump. in all deposition experiments, the power was 200 w with an ultrapure ar working gas pressure of 3.5 × 10−3 torr. the substrate temperature during growth was below (85 ◦ c). the deposition time was 45 min. for the normal incidence 10 min. was used, for the deposition rate of the glancing angle depositions of mo nanorods was measured utilizing quartz crystal microbalance (inficonq-pod qcm monitor, crystal: 6 mhz gold coated standard quartz) measurements and sem image analysis to be about 10 nm min−1. first, the deposition rate of mo nanorods was monitored on the qcm. since the distance between the target and the qcm is smaller than that of the substrate, the deposition rate of mo nanorods on the substrate was determined by dividing the measured film thickness from cross-sectional sem images by the deposition time. then, a correction distance factor was calculated dividing the deposition rate on the substrate to that on the qcm. glad allows coating teflon only on the tips of the mo nanorods, resulting in a bi-layer nanorod structure (metal base and teflon tip), while normal incidence results in a continuous teflon thin film coating. a custom-made teflon (applied plastics technology) disk was used as the sputtering target. the target was 0.3175 cm thick and 5.08 cm in diameter. the substrates (arrays of pt nanorods on a silicon wafer piece) were rotated around the surface normal with a speed of 2 rpm. the deposition was performed under a base pressure of about 2 × 10−6 torr. during teflon deposition experiments, the power was 150 w with an ultrapure ar working gas pressure of 3.2 × 10 −3 torr. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 142 in a similar fashion to the mo nanorods, the deposition rates of the normal incidence and glancing angle depositions of teflon nanopatches were measured using sem image analysis and qcm measurements to be about 13 and 4 nm.min−1, respectively. the surface morphology of the nanocomposite (mo/teflon) and (ag/teflon) structures were analyzed using an sem. the hydrophobic behavior was investigated by contact angle measurements using a vca optima surface analysis system (ast products, inc., ma). finally, the surface energy measurements were also performed using the two-liquid method to confirm the contact angle measurements. 3results and discussion: figure (2a,b) shows a top and cross sectional views of molybodium thin films on silicon flat substrate using a phsical vapor deposition process. as can be seen, atomic shadowing of molyebodium islands and clusters of mo on the si substrate which leads to the growth of highly porous moeybodium thin film on silicon flat surface. a scanning electron microsope (sem) unit was used to study the morphology of mo thin film and (mo/teflon) nanrod on silicon wafers. figure (3a,b,c) is a typical sem images of pure mo nanorods and unique structure with mo nanopillars growth. this morphology as a result of the stochastic nucleation process of moleybodeum on wafers. glad technique result in growing the mo with 100 nm in height as shown in figure (2) which the mo deposition flux iminge on the substrate from glancing angle (α=87 o ) with a substrate rotation at (2rpm). the development of mo nanorods which are separated on narrow pores is due to the growing clusters shadow unoccupied sites as well as smaller smaller clusters from the incident vpor flux, whle the limited a datom surface mobility suppresses the filling of voids by diffusion. figure (4) shows the sem images of teflon thin film deposited on si and the composite structure mo nanorods with teflon tips which are deposited using the rf sputtering technique at normal incident times of 5 min. the normal incidence deposition of teflon on mo nanorods results in a contineouse teflon capping thin film layer lying mainly at the tips of mo nanorods. figure (5) presented contact angle measurement of conventional flat teflon thin film deposited on si wafer, mo thin film deposited on si substrate and mo nanorods with normal incidented deposited teflon film. the contact angle larger than 90 o denotes a hydrophic surface. mo and teflon exhibit different behavior when their surfaces get in contact with wter droplet. it is shown that from the figure (5) the contact angle of mo thin film deposited on si substrate was about 40 o givimg a hydrophilic behavior of the surface while the contact angle for the normal depositon flat teflon thin film was about (109.3 o ) indicating a hydrophobic surface. as it can be seen from figure (4) the contact angle measurement of composit (mo/teflon) was about 116.7 o reported a significant increase in the hydrophobicity of hydrophilic mo nanostructures, this may be due to the presence of low energy teflon nanopatches with large surface energy teflon. 4conclusions: nanostructured mo films were prepared by glancing angle deposition (glad) method which exhibit highly oriented nanostructure composite of (100 nm) pillars columns. samples were characterized using scanning electron microscope (sem) and our resultsshow a conventional mo thin films exhibited a continuous surface and vertical mo nanopillars on si wafer. it was have demonstrated that the hydrophilic property of mo nanorod surface was shifted to hydrophobic by deposition of small amount of teflon at the tips of mo nanostructures. the contact angle measurement show high value as 116 o which give an indication of increasing in the hydrophobicity of originally hydrophilic mo nanorods with contact angle (140 o ). c al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 143 references: 1boduroglu s., cetinkaya m. and dressick w. (2007) " controlling the wettability and adhesion of nanostructured poly (p-xylene) films " langmuir 23, 11391-11395. 2gish d., summers m. and brett m. (2006)" morphology of periodic nanostructures for photonic crystals grown by glancing angle deposition" fund. and appl. 4, 23-39. 3kosiorek a., kandulski wi and chudzinski p. (2004) 'shadow nanospher lithography: simulation and experiment", nano lett. vol.4, no.7, 1354-1363. 4kuo c. w., j. y. shiu, and p. l. chen. (2003) "sizeand shape-controlled fabrication of large-area periodic nanopillar arrays. chemistry of materials 15, 2917. 5kuo c. w., j. y. shiu, p. l. chen, and g. a. (2003) "somorjai. fabrication of sizetunable large-area periodic silicon nanopillar arrays with sub-10-nm resolution". journal of physical chemistry b 107, 9950. 6li w., xu l., zhao w. and huang x. (2007) "fabrication of largescale periodic silicon nanopillars arrays for 2d nanomold using modified nanosphere lithography". appl.surf.sci 253, 9035-9038. 7nang s., xia g., hongbott h. and yi k. (2007) " structural and optical properties of nano structured tio2 thin films fabricated by glancing angl deposition ", j. all. and comp. 431, 287-291. 8patzig c. , berned r., bodo f. and hurtmud s. (2008) " growth of si nanorods in honeycomb and hexagonal-closed-packed arrays sing glancing angle deposition", j.appl.phys. 103, 024313. 9wisam j. , sharma r. and karabacak t. (2009) " hydrophobic mettalic nanorods with teflon nanopatches" nanotechnology 20, 275302. 10zhoj c. and galld. (2007) " growth competition during glancing angle deposition of nanorod honeycomb arrays" appl.phys.lett. 90, 093103. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 144 (a) (b) figure (1)aschematic of glad technique, bglancing angle deposition device in the lab. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 145 figure (2)sem images of mo thin films on si substrate. • base pressure: 2 x 10e-06 mbar • operating pressure: 3.2 x 10e-03 mbar • power: 200 w • deposition time: 10 min • gas: ar: 12.8 ccm • tilt: 0 degree • rotation: 2 rpm a b a figure (3) sem images of mo nanorods on si substrate. • base pressure: 1.5 x 10e-06 mbar • operating pressure: 3.5 x 10e-03 mbar • power: 200 w • deposition time: 45 min • gas: ar: 12.8 ccm • rotation: 2 rpm • tilt: 87 degree b a c al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 146 figure (4) sem images of teflon thin film on mo nanorods on si substrate. • normal deposition of teflon • rf power supply • base pressure: 2 x 10e-06 mbar • operating pressure: 3.2 x 10e-03 mbar • power: 150 w • deposition time: 5 min • gas: ar: 12.8 ccm • rotation: 2 rpm • tilt: 0 degree al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 147 figure (5) contact angle measurement. mo thin film on si substrate. teflon thin film deposited on si substrate. teflon thin film deposited on mo nanorod/si substrate. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 504 effect of micro-sized on thin plate specimen using fractographic analysis m. abdul razzaq mechanical engineering department, college of engineering, alqadisiyia university, iraq malhindawy@gmail.com received 1 july 2015 accepted 30 august 2015 abstract in the last four decades, the car body thickness has reduced significantly from almost 1.5 mm to below 0.5 mm. this was mainly due to the demand for weight reduction for saving more fuel cost. besides being thinner, maintaining the high strength of car body was possible by using a newly developed high-strength steel thin plate. however, mechanical properties of bulk materials which usually tested using a standard big size sample are not necessarily representing the actual properties of the material when dealing with very thin and small size components. this drives the research on the mechanical properties of the micro-sized specimen for the production of tiny metal-based components. in this study, tensile and fracture behaviors of the micro-sized specimen were investigated. the materials used were 100 and 300 micron stainless steel s304 thin plates, the tests were carried out on specimens of astm a313m spring steel materials. the results showed that 100 micron thin plate exhibited higher tensile strength with no clear evidence of yielding as compared to 300 micron plates. the fracture morphology images observed by scanning electron microscopy (sem) revealed that both specimens fractured in ductile mode. formation of dimples on the fracture surface could be recognized easily in 300 micron sample at higher magnification as compared to 100 micron sample. keywords: micro-sized specimen, tensile test, fracture behavior, thin plate, s304 steel تأثير العينات الصغيرة على الصفائح المعدنية باستخدام الكسر الجزيئي دكتور محمد عبد الرزاق :الخالصة جسم من عالية قوة على والحفاظ أرق، كونه إلى إضافة وتقليق كلفة األنتاج الوقود تكلفة من المزيد لتوفير الوزن خفضلغرض 5.1 من أقل إلى ملم 5.1 حوالي من ملحوظ بشكل السيارة جسم سماكة من قلل قد الماضية، األربعة العقود في لقد لوحظ السيارة تم التي للمعادن المستخدمة الميكانيكية الخواص لوحظ عند استنتاج ذلك ومع. القوة عالية الرقيقة الصلب الواح باستخداموذلك ملم ذات المكونات مع التعامل عند للمواد الفعلية خصائصال بالضرورة تمثل ال القياسية الحجم كبيرة عينة باستخدام عادة اختبارها على القائمة مكونات إلنتاج الحجم الصغيرة للعينات الميكانيكية الخواص على للبحث يدفع هذا. صغيرةالو جدا رقيقةال األحجام المستخدمة المواد وكانت. الحجم الصغيرة لعينةالكسرالو الشد سلوكيات من التحقيق تم الدراسة، هذه في. صغيرة المعادن mailto:malhindawy@gmail.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 505 ميكرون أظهرت ارتفاع قوة 555ذات رقيقةال الصفائح أظهرت النتائج أنمايكرون من الفوالذ المقاوم للصدأ وقد 055و555 مايكرون وكذلك لوحظ من خالل المجهر األلكتروني ان جميع العينات قد كسرت في وضع 055مع األلواح ذات مقارنتا الشد ام. 050الدكتايل. علما ان المقايسة المريكية اي اس تي ام 053العينات الصغيرة , فحص الشد , سلوك الكسر, الصفائح الرقيقة , ستيل حية :الكلمات المفتا introduction stainless steel is a material widely used in the industrial sector in line with technological developments. properties of stainless steel make it suitable for components stressed. it is stainless steel, high-stress value and the ability to operate at high temperatures allows it to become widely used. the fact that material properties change with specimen size has been well known for several years [1, 2]. in recent years, the market demand at the micro level such as pin connector, micro screws, springs, ic sockets, micro gears and micro shaft so has increased significantly as a result of the downsizing of the product. micro components have also been widely used in many industries including automotive, biomedical, aerospace and electronics. miniaturization technology has become more important in the fabrication of micro parts. when the size of the decline to the microscale changes in the mechanical behavior of materials and the effects of the so-called size effect [3]. effect size is characterized by grain size, the size of the specimen and the size of the surface topography. the mechanical properties of the material properties that expose the behavior of elastic and non-elastic when a force is applied thereby indicate its suitability for mechanical applications. such as modulus of elasticity, tensile strength, elongation, hardness and fatigue limit [4] .the tensile test is one method of evaluating the structural response of steel to the applied force, with the result expressed as a relationship between stress and strain. this work examines the backdrop of stainless steel s304 specimens, which affects the experimental method. the experimentation was held out on specimens having different thicknesses to test tensile fracture behavior of dislocation density specimens. an experiment conducted on a specimen size of 0.1mm and 0.3mm micro. this research involves the use of some equipment that universal testing machine (utm), machine polish and scanning electron microscopy. before the tests are done by using the universal testing machine was going through the process of heat treatment of quenching, it is intended to restore the mechanical properties and microstructure of specimens repairs. dumbbell-shaped specimens will be used for this form easily held by the machine, and the effect of fracture is clearly visible on the specimen. experimental procedures material and specimen the material used was a type stainless steel s304. the chemical composition of the material (wt. %) is listed in (table 1). dumbbell-shaped specimens with a thickness of 0.1mm and 0.3mm were machined as shown in (fig.1). the dimensions of the specimen under a millimeter in size used for both stainless steel s304 specimens of different thickness. emery paper mechanically polished the specimen surface, then buff-finished before the experiment. the microstructures before and after the tensile test with a thickness of 0.3mm and 01mm are shown in (fig. 2 (a, b, c, d)). the specimens with a thickness of 0.3mm have a strong atomic bonding between the layers upon layers that complicate it undergoes deformation to slip from its original form. while for specimens with al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 506 thickness 0.1mm bonds between atoms are weak layer after layer and makes it easy to slip from its initial position. procedure these experiments involved the use of stainless steel s304 dumbbell-shaped. experiments will be performed on specimens with a thickness of 0.1mm and 0.3mm. initially, the specimen underwent quenching in a furnace at 700°c for one hour and cooled in the furnace. micro-sized specimens only use emery paper mechanically polished the specimen surface grade (800-1200) for grinding process, then buff-finished using polishing machines before the experiment. to obtain microstructure on the surface of the etched specimen process will be carried out in (5-7 sec). after the tensile tests are performed on the specimen thickness of 0.1mm and 0.3mm by using the universal testing machine (utm), tensile tests were performed on specimens cut off. this test is performed to obtain the mechanical properties of the material. effects fracture of fractographic analysis. fracture surface observations carried out to identify the mechanism of tensile test fracture of stainless steel s304. the fractography observation shows, two specimens observed, a 1st specimen with thickness 0.1mm and 2nd specimen thickness of 0.3mm, which has done the tensile test represented by (fig. 5). through observation, the discussions focused on the differences on the surface of the specimen due to the effect of specimen thickness. the significant difference was seen the pattern, the cleavage and dimples in the fracture surface.the tensile test will be observed by using a scanning electron microscope (sem). results and discussion in this work, we conducted micro-tensile tests and fracture behaviors for stainless steel s304 specimens with two different thicknesses 0.1mm and 0.3mm to evaluate the mechanical properties of the micro-sized specimen, the production of tiny metal-based components. tensile test analysis the stress–strain curves shown in (fig. 3, fig. 4) obtained from the micro-tensile test of 0.1mm and 0.3mm thickness stainless steel s304 specimens respectively. the micro-tensile test was conducted using three micro-specimens labeled as a specimen a, b and c in each figure. the micro-tensile test for specimen 0.1mm thickness, as indicated in (fig. 3) the stress–strain curve at the beginning of the elastic stage stainless steel s304 is the same. changes in readings between specimens a, b and c occur when the specimen reaches the ultimate strength. specimen c has the ultimate strength higher than that of specimens a and b. therefore, the experiments on specimens with a thickness of 0.1mm can be formulated continuous tension is applied to the specimen will enter the phase of strain hardening up at one stage graph shows. the specimen experienced a dislocation or plastic deformation, in this case, the specimen will begin to an extension. the appearance of small cracks will grow and subsequently subjected to continuous tension will break the specimen. meanwhile, the micro-tensile test for specimen 0.3mm thickness, as shown in (fig. 4) the difference compared to a specimen of stainless steel s304 with a thickness of 0.1mm. while, the specimen of a, b and c have the high yield strength before reaching the ultimate strength and fracture point. the high yield strength of the specimens a was 810mpa, specimen b was 773mpa, al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 507 and specimen c was 774mpa. thus, the overall reading of the stress-strain curve between a, b and c specimens found there reading gap for both specimens but have the same pattern graph form so that the specimen was broken. based on the (tables 2, table 3) the yield strength values recorded between specimens with 0.3mm thickness readings showed no significant difference. however, for a specimen with a thickness of 0.1mm yield strength value is not specified because it does not involve one of the processes during plastic deformation. the ultimate strength of all specimens is shown in (tables 2, table 3) which have a thickness of 0.1mm, and 0.3mm show subtle differences. all specimens have an average ultimate strength between 1160mpa up to 1163.33mpa. specimens having a thickness of 0.1mm indicate high strength compared to specimens having a thickness of 0.3mm, but the difference was almost the same for both thicknesses. this experiment proves that the thickness of the sample does not affect the ultimate strength. then also (tables 2, table 3) shows the average breaking strength shows different flow, where the sample has a thickness of 0.1mm, has average breaking strength 1020mpa. while, the sample thickness is 0.3mm has average breaking strength 976.67mpa. so these experiments showed that the sample thickness of 0.1mm has high fracture resistance properties compared to 0.3mm thickness. the significant percentage elongation between specimens of different thickness also shown in (tables 2, table 3). specimen 0.3mm thickness has a high percentage compared to the specimen of 0.1mm thickness. it showed higher thickness can elongation higher prior to fracture than the thickness of a thin specimen. that is lead to the thickness of a material affects the percentage elongation but does not affect the strength of a material. theoretically stainless steel s304 specimen thickness 0.3mm has a higher elongation percentage due to the atoms in the metal lattice space will move during plastic changes occur and more energy necessary to ensure that, the process of dislocation occurs between the layers upon layers of metal lattice. overall, the tensile tests carried out showed that the pattern of changes in the yield strength, ultimate strength and breaking strength for each thickness of 0.1mm and 0.3mm. pattern reading shows the ultimate strength readings for samples with a thickness of 0.1mm and 0.3mm is almost the same this proves that the thickness does not affect the strength of a material. this statement reinforced by [5], namely the percentage of different carbon will determine the mechanical properties of stainless steel. improved reading on stainless steels304 proves that the ultimate strength and breaking strength increased with the reduction in thickness of the specimen. this change occurs because when the grain size is more or less approaching the specimen thickness, the grain function plays a role in influencing the mechanical properties of stainless steel [6]. this situation is influenced by changes in the mechanical properties of polycrystalline to single crystal when the specimen geometry changes. each grain will play a significant role influencing the changes in the properties of materials change [7]. with these changes in the thickness of the specimen makes the elastic properties of the material becomes very difficult due to the specimen fracture. however, the thickness of the sample is also influenced by the grain size diversity contained in the specimen thickness and resistance to dislocation movement of the specimen. in the case of comparison magnifications 100x, 2000x for stainless steel s304 with a thickness of 0.1mm, and 0.3mm at (fig. 5 (a),(b)). moreover, based on the tensile tests results that's reinforced sample thickness 0.1mm have a lower elongation percentage compared to samples with a thickness of 0.3mm as shown in (table 2, table 3). then, 0.3mm sample involves changes in yield stress but it did not happen in the sample of thickness 0.1mm. can be concluded that the sample has a bond between the layers of 0.3mm strong grain and this makes it difficult to broken while the 0.1mm samples have weak bonds between the layers and less. moreover, it is easier to be broken grain samples that have a strong bond between the coating will produce rough surface samples. these al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 508 differences will affect the nature of the material. however, the pattern of both specimens fracture almost in the ductile mode because the sample surface rough, dark and fibrous then small scattered areas of cleavage fracture were seen. the representative sem fractography of the tensile fractured specimens with 10000x magnification shown in (fig. 5(c)). the images showed a small grain size and arranged for a sample of 0.1mm and 0.3mm sample image shows the coarse grain size and unstructured. the fractographic observation shows that tensile fracture occurs mostly intergranular (typically dimple) fracture mode. that could be recognized easily in 300 micron sample at higher magnification as compared to 100-micron sample because the dimples are the concentration stresses area. conclusions based on our studies, some findings have been formulated as follows: 1) the microstructure showed that the specimens with a thickness of 0.3mm has a strong atomic bonding between the layers upon layers that complicate it undergoes deformation to slip from its original form. while for specimens with thickness 0.1mm bonds between atoms are weak layer after layer and makes it easy to slip from its initial position. 2) the stainless steel s304 samples produced in this tensile test study showed the thickness of the specimen does not affect the nature of the material. the results obtained from specimens of different thickness shown the ultimate strength of the material in the range matching. while, the percentage of elongation of the specimen thickness of 0.1mm and 0.3mm is different due to the influence of atomic bonding between the layers upon layers. greater thickness will complicate the enactment of the derailment thereby increasing the percentage elongation of the specimen. 3) the fractographic analysis shows the pattern of both specimens fracture almost in the ductile mode. then small scattered areas of cleavage fracture were seen for both samples. formation of dimples on the fracture surface could be recognized easily in 300 micron sample at higher magnification as compared to 100-micron sample. acknowledgement this work was supported by frankfurt university. the authors would like to thank zwich laboratory (tensile test lab.) for assisting in the experiment, analysis, and tests. also the cell full center for using sem. references [1] neugebauer, c., tensile properties of thin, evaporated gold films. journal of applied physics, 1960. 31(6): p. 1096-1101. [2] doerner, m., d. gardner, and w. nix, plastic properties of thin films on substrates as measured by submicron indentation hardness and substrate curvature techniques. journal of materials research, 1986. 1(06): p. 845-851. [3] chan, w.l., et al., modeling of grain size effect on micro deformation behavior in microforming of pure copper. materials science and engineering: a, 2010. 527(24–25): p. 66386648. [4] jaswin, m.a. and d.m. lal, effect of cryogenic treatment on the tensile behaviour of en 52 and 21-4n valve steels at room and elevated temperatures. materials & design, 2011. 32(4): p. 2429-2437. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 509 [5] yuan, w.j., et al., influence of specimen thickness with rectangular cross-section on the tensile properties of structural steels. materials science and engineering: a, 2012. 532(0): p. 601-605. [6] zhang, g.p., k. takashima, and y. higo, fatigue strength of small-scale type 304 stainless steel thin films. materials science and engineering: a, 2006. 426(1–2): p. 95-100. [7] chen, a.y., et al., the influence of strain rate on the microstructure transition of 304 stainless steel. acta materialia, 2011. 59(9): p. 3697-3709. table (1): chemical composition (wt. %) c mn f s si cr ni 0.08 2.00 0.045 0.03 1.0 18.0-20.0 8.0-11.0 table (2): mechanical properties for stainless steel s304 with thickness 0.1mm no. yield strength at 0.2% (mpa) ultimate strength (mpa) breaking strength (mpa) elongati on (%) a 1030 1170 1040 9.5 b 1020 1180 1010 6.6 c 1020 1140 1010 11.3 average 1023.33 1163.33 1020 9.13 table (3): mechanical properties for stainless steel s304 with thickness 0.3mm no. upper yield strength (mpa) ultimate strength (mpa) breaking strength (mpa) elongation (%) a 810 1170 1010 27.5 b 773 1160 965 25.4 c 774 1150 955 26.4 average 785.67 1160 976.67 26.43 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 510 figure (1): specimen configuration according to astm 313m figure (2): microstructures of stainless steel s304specimens before and after the test tensile: (a) before the test tensile t= 0.3mm at 50x magnifications; (b) before the test tensile t= 0.1mm at 50x magnifications; (c) after the test tensile t= 0.3mm at 50x magnifications; (d) after the test tensile t= 0.1mm at 50x magnifications. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 511 figure (3): stress-strain curves for specimens of stainless steel s304 at 0.1mm thickness figure (4): stress-strain curves for specimens of stainless steel s304 at 0.3mm thickness. 0 200 400 600 800 1000 1200 1400 0 2 4 6 8 10 12 s tr e ss ( m p a ) strain (%) a b c 0 200 400 600 800 1000 1200 1400 0 5 10 15 20 25 30 s tr e ss ( m p a ) strain (%) a b c al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 512 0.1mm specimen thickness 0.3mm specimen thickness (a) (a) (b) (b) (c) (c) figure (5): sem fracture surface of tensile specimens, with a thickness of 0.1mm and 0.3mm stainless steel s304: (a) magnification at 100x, (b) magnification at 2000x, and (c) magnification at 10000x. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 452 assessment of fatigue crack rate under cyclic loading assistant lecturer: muhanad hamed mosa university of al-qadisiya, college of engineering, department of mechanical engineering email: alafaq_eng@yahoo.com received 7 april 2014 accepted 21 may 2014 abstract fatigue crack growth (fcg) in structures subjected to variable amplitude (va) loading is a complex phenomenon. analysing of fcg rate is important for the reliable life of engineering structures. it is difficult to model all the parameters influence fcg correctly due to the random nature of the va loading as well as the number and complexity of the mechanisms involved in the fcg problems. . it has been found from the literature review that no universal model has been developed to analyse the crack growth condition under va loading. in addition, no general understanding has also been agreed among researchers for any available models. therefore, the main objective of this work is to investigate the fcg under va loading based on fcg models also to propose a suitable model for va loading. the work describes some of the fcg models for predicting the fatigue lives and fcg rates. for the simulation part of this study, towards prediction of crack propagation under cyclic, variable and random loading were used. the results had been carried out based on the austen, modified forman and nasgro models. there are many factors affecting the fcg, which shown with great influence such as; initial crack length, load sequence, aspect ratio and stress ratio. keyword: fatigue crack growth (fcg), variable amplitude (va), finite element method (fem) introduction the phenomenon of fatigue has been discovered in the post-incident findings of the versailles incident in 1842. since then, engineers and scientists have developed models to predict the fatigue life of components and to incorporate the fatigue analysis in the design. when pressure vessels and piping are subjected to fluctuations in stress, they may lead to the development of fatigue cracks. fatigue cracks extend slowly, and this is generally with a very small increment of crack growth occurring with each cycle, and with little or no evidence of plastic deformation. the cracks can continue to grow until they completely cause failure of the component, member or structure by fast fracture, plastic collapse or other mode, which prevent service duties being performed. the service load histories may completely in random pattern. it is either to be simple and repetitive or at the other extreme. in general, prediction models published in the literature employ basic material fatigue data as references. such data can be fatigue limits, stress-life (s-n) data, fatigue diagrams, crack growth data, and fracture toughness for the final failure. these prediction models that are used for crack growth under variable amplitude (va) loading vary from simple modifications on the constant amplitude (ca) baseline up to the complex models with detailed descriptions of relevant fracture mechanisms. for instance, some models calculate crack growth by averaging over the applied load spectrum, while many others tend to calculate it using the cycle-by-cycle analysis. despite the on-going development of the prediction models mailto:alafaq_eng@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 455 towards a more accurate description of the phenomena, there seems to be no general agreement about which mathematical description is the most useful. in fact, the simplest prediction models are still being used by many engineers. the alternative to make prediction is to carry out experiments for specific fatigue questions when they arise. unfortunately, testing is not always possible due to geometry complication, time, costs etc (simonsen & tornqvist 2004; richard et al. 2008). this is even complicated by the fact that it is not at all easy to accomplish experimental fatigue conditions which will give a relevant answer to the question raised. thus, the overall fatigue life of a component is generally defined as follows: “total life = initiation life + propagation life”. this can be represented in a block diagram of figure 1.1. the prediction of fatigue properties of structures and avoiding structural fatigue were recognised as engineering problems in the early decades of the 20th century. high stress concentrations were understood and taken as possibly harmful and should therefore be avoided. the significance of stress concentration factors had been identified before 1950 and designers also realised that the fatigue performance of a structure was dependent upon improved detail design (schijve 2003). in 1950s, many investigators mentioned how early in the fatigue life they could observe microcracks. since then, it has been clear that the fatigue life under cyclic loading consists of two phases, namely the crack initiation life, followed by a crack growth period until failure (khan et al. 2004). predicting fatigue crack growth in metals under random loadings is a difficult task, particularly because of the load history effects, which are known for decades to stem from plastic deformation in the vicinity of the crack tip (schijve 1999; skorupa 1999; hamam et al. 2007). in addition, history effects are closely related to the elastic–plastic behaviour of the material. although many fatigue crack growth (fcg) models have been developed, none of them enjoys universal acceptance. each model can only account for one or several phenomenological factor(s). from an engineering point of view, the experience of dealing with fatigue problems in the beginning of the previous century was still a matter of trial and error. in later decades, however, continued research (schijve 2003; huang et al. 2005) clearly indicated, that the number of variables that could affect the fatigue strength and the fatigue life of a structure is large. in principle, it is correct to consider fatigue as a phenomenon, which is characterised by microcrack initiation, crack growth as an invisible microcrack, and later as a visible macrocrack which finally leads to a complete failure. unfortunately, this concept does not mean that the fatigue phenomenon occurs in the same way in all metallic materials (schijve 2003).though many damage models have been developed, none of them enjoys universal acceptance (fatemi & yang 1998; paris et al. 1999; molent et al. 2008). each damage model can only account for one or several phenomenological factors, such as load dependence, multiple damage stages, nonlinear damage evolution, load sequence and interaction effects, overload effects, small amplitude cycles below fatigue limit and mean stress. due to the complexity of the problem, none of the existing predictive models can encompass all of these factors. therefore, the applicability of each model varies from case to. fracture mechanics seeks to establish the local stress and strain fields around a crack tip in terms of global parameters such as the loading and the geometry of the structure. the fracture mechanical approaches are usually divided into linear elastic solutions and non-linear methods. for linear elastic materials, irwin (1957) suggested describing the stresses in the vicinity of the crack by stress intensity factors (sifs). there are basically three different types of sifs, with each describing one of the deformation modes illustrated in figure 1.2. the superposition of al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 452 these three modes forms the general case of cracking. meanwhile, the deformation modes can be characterised as follows: (a) mode i: the in-plane tensile mode where the crack surface is symmetrically opened, (b) mode ii: the sliding or shear mode which is present when the crack is exposed to skewsymmetric in-plane loading, (c) mode iii: an anti-plane mode where the crack surface is twisted by forces perpendicular to the crack plane. in the simulations of crack propagation in linear elastic fracture mechanics (lefm), it is usually the combination of modes i and ii which is of greatest interest. irwin (1957) analysed this inplane mixed mode problem, and using the westergaard (1939) stress functions, he found an analytical solution for the stress distribution in the vicinity of the crack tip. simulation of fatigue crack growth assessing the behaviour of fatigue cracks in any structure is a complex and uncertain process due to the large number of parameters that may influence the crack growth process. for instance, pipes or tubes contain defects from the manufacturing, installation and servicing processes. the defects can affect the safety of the structures, and even depress their service life that may lead to enormous economic costs and jeopardise the surrounding ecological environments. numerous models have been developed over the past few decades and these have taken different approaches to modelling fcg; however, no universal or all-encompassing model exists. most models are developed for a specific application and they incorporate the main parameters influencing fcg for the structure in question. a successful model is like a balance between being able to accurately predict the crack growth rate and its simplicity. such a model is beneficial in planning inspection intervals, determining required maintenance and minimising the problem of crack propagation in any future designs. the fatigue life prediction has brought significant advantages to designers, not least of all the abilities to do up-front fatigue calculations long before a prototype available. however, the combination of the two technologies also poses challenges. the engineering need for prediction models and some of the ca and va loading fcg models were discussed. in this chapter, the methodology to select three of these models (the austen, modified forman and nasgro models) and the fatigue life and fcg prediction as well as the factors affecting it. then, the experiments setting are presented so as to enable the readers to fully understand how this work is accomplished. the start of a fatigue failure is a strictly local process and also depends on the dynamics of the system. it is important to highlight that the time history of stress or strain, at the exact location where a crack is going to start, is the critical factor whereas the general distribution of these parameters throughout the component is of secondary interest. accurate measurement, data acquisition, analysis, and testing are among the key factors in the process of calculating structure performance. most structures survive in a va loading environment and a predominant failure mechanism under these conditions is fatigue. exploiting fatigue knowledge and the use of computer-based analysis techniques, at an early stage in the design process, can dramatically reduce the developmental period. therefore, the designer has the opportunity to estimate the effects of changing geometry, material and loading performance. many shell structures such as pressure vessels or pipelines, contain defects from the manufacturing and servicing processes. these defects can affect the safety of the structure and even depress their life; may lead to enormous costs and jeopardize the surrounding ecological al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 452 environments. for fatigue life prediction (s-n), the finite element technique was used for modelling and simulating the case study of the shell as a cylinder with infinite length in threedimensional mesh, as shown in figure 1.3.selecting the right techniques of meshing are based on the geometry, model topology, analysis objectives and engineering judgment. triparametric solids with the topological shape of a brick or wedge can be meshed either hex or wedge elements. any other form of the triparametric solid can only be meshed with tetrahedral (tet) elements. the auto tetmesh approach is a highly automated technique for meshing solid regions of the geometry. it creates a mesh of tetrahedral elements for any closed solid including boundary representation (b-rep) solid. tetmeshing produces high quality meshing for b-rep solids model imported from the computer aided design (cad) systems. since the tetrahedral is found to be the best meshing technique, the tet4 (4 nodes tetrahedral) version of the cylinder head was then used for the initial analysis. in addition, the tet4 compared to the tet10 (10 nodes tetrahedral) mesh using the same global mesh length. the tet10 mesh is presumed to represent a more accurate solution since tet4 meshes are known to be dreadfully stiff. for this purpose, the finite element analysis technique, with tetrahedral elements (10 nodes) shown in figure 1.4, was applied to model and simulate based on the msc nastran/patran analysis codes (msc 2005). in order to study the fatigue life prediction, a shell with t/d < 0.1 (where t is the thickness and d is the diameter) and l/d > 10 (where l is the length) was analysed. the cycle-by-cycle analysis can be performed with or without involving interaction effects, i.e. the effects of a load cycle on the crack growth in later cycles. both the constant and random amplitude loadings are shown in figure 1.5. for the va loading, similar programmable va load histories, as given by with different values, were used in the analysis with different load sequences and values ranging from high to low or from low to high, as shown in figure 1.6. the presence of the interaction effects is always altering the crack growth rate, under the application of the va loading. in order to correctly predict the crack growth under va loading, it is necessary to involve the interaction effects, while developing the prediction models, as a part of cycle by cycle analysis using different models. the ca loading has been developed to correlate fcg rates for different values. the steel used in the fabrication of pressure vessels is usually of two kinds, viz. carbon steel and alloy steel. in the pressure vessel steel, carbon is of prime importance because of its strengthening effect. it also raises the transition temperature, lowers the maximum energy values and widens the temperature range between completely brittle behaviour. manganese (up to 1.5%), on the other hand, improves low temperature properties (asm 1993). of all the different kinds of steel, those produced in greatest quantity fall within the low carbon classification. these steel types generally contain less than 0.25 wt. %c and are unresponsive to heat treatments intended to form martensite, as strengthening is accomplished by cold work. meanwhile, microstructure consists of ferrite and pearlite constituents. as a consequence, these alloys are relatively soft and weak, but have outstanding ductility and toughness, in addition to the fact that they are machinable, weldable and most important of all, steel is the least expensive to produce. they typically have yield strength of 585 mpa, tensile strengths between 637 and 825 mpa, and a ductility of 20-25 %el. in particular, astm a533 is one such kind of steel which has applications in pressure vessels (astm standard v1.04).in this analysis, the material of the shell astm a533 steel has been used. modelling and simulation it is important to note that the fatigue life prediction based on modelling is very time consuming. for example, an off-shore platform designed to withstand 108 cycles in a 30 year life would require a 30 year test at 0.2 hz to validate the design (msc 2005). computer-based prediction methodologies can perform the same validation with an equal accuracy in a very small fraction al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 452 of the time (e.g. less than two hours) at a very small fraction of the cost. such prediction software requires the fatigue crack growth to be accumulated on a cycle-by-cycle basis and it must also incorporate the complex effects of the stress history, crack closure, static fracture modes and notches and be able to predict the environmental influences on fatigue crack growth rates (corrosion fatigue). stephens et al. (2001) have estimated that between 50% and 90% of these failure are due to fatigue. as a result of the recent advances in the finite element method (fem) and its application to fracture mechanics, various numerical methods exist to calculate the fracture parameters and to evaluate the fcg models. one of the advantages of the numerical method is that accurate results can be obtained for complex problems of any geometry and crack configuration in a fraction of the time and cost, as compared to the alternative of experimentation. finite element approach the start of a fatigue failure is a strictly local process and it is also one that depends on the dynamics of the system. the time history of stress or strain, at the exact location where a crack is going to start, is a critical factor and a general distribution of these parameters throughout the component is of secondary interest. this is precisely why the finite element analysis (fea) is important in this particular discipline. with fea, an analyst can choose any location within a model and concentrate on it. in fact, using fea can give a tighter control over the move from general geometry and loading to the local parameters, and allows dynamic factors to be dealt with more analytically. the concepts of fracture mechanics that were derived prior to 1960 are applicable only to materials that obey the hook’s law. although corrections for small-scale plasticity were proposed as early as 1948, these analysis are restricted to structures whose global behaviour is linear elastic. since 1960, fracture mechanics theories have been developed to account for various types of nonlinear material behaviour (i.e. plasticity and viscoplasticity) as well as dynamic effects. all of these more recent results, however, are extensions of lefm. thus a solid background in the fundamentals of lefm is essential to an understanding of more advanced concepts in fracture mechanics. the linear static analysis was performed using the finite element software to determine the stress and strain. the finite element technique was used for modelling and simulation of the case study of the shell as a cylinder with infinite length in three-dimension mesh shown in figure 1.3. for this purpose, the f technique with tetrahedral elements (10 nodes) shown in figure 1.4 was being used for the modelling and simulating based on msc nastran/patran analysis codes. to study the fatigue life prediction a shell with t/d < 0.1 and l/d > 10 (where t is the thickness, d is the diameter and l is the length) was analysed.the results of the maximum principle stresses and strains are used for the subsequent fatigue life analysis, using the cyclic load history (discussed above) as an internal pressure to the shell. figure 1.7 shows the contour (image) of the stress distribution on the shell. software codes it is important to note that more than one software was used in this work for the modelling or the experiments. firstly, the fatigue life predication (s-n) was performed based on the msc nastran/patran software (msc 2005). the crack growth software, developed by the ncode (2003), offers engineers the facilities to predict defect tolerant fatigue life based on all these aspects. these diagnostic techniques enable iteration and interpolation with different material, geometry and history inputs, as well as probably the most important variable, i.e. the initial crack size. as for the modelling part of this work, the glyphwork software was used to predict fcg after building the block system of all parts shown in figure 1.8. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 452 results and discussion in general, the plastic-zone size at crack front increases as it grows in a metallic material under cyclic loading. at low stress-intensity factor levels, the plane-strain conditions should prevail as the plastic-zone size becomes large compared to thickness. the fcg life under ca loading, using three different fcg models (the austen, modified forman and nasgro models) is shown in figure 1.9. based on the simulation results, the austen model was found to give the lowest value of life, i.e. 35% less than the nasgro model. on the contrary, the modified forman model gave a better life than that by 20%, while the nasgro model revealed a higher life, i.e. 128 x 103 cycles to failure. the differences in fatigue lives predicted are mainly due to basic theoretical background for each model. the effects of using different fatigue crack growth models on the fatigue crack growth rate are shown in figure 1.10. the differences are related to the results presented in the a-n curves. the modified forman model is capable of describing region iii of the fatigue rate curve as well as included the stress ratio effect, while the nasgro model take into account the crack closure effect as well as the previous factors. the austen model is including the crack closure effect and capable of representing data in region ii same as the other two models. so the nasgro model represents more factors than the other two models and gives better representation of the data. conclusion the methodology of simulation and modelling as well as the cyclic experimental setting suggested clarifying the objectives of this work. the present research focused on studying fcg under variable and random loadings. the finite element modelling and analysis of pressure vessel or piping were utilised to predict stress-life. the factors affecting the s-n curve, such as mean stress, wall thickness, surface finish, type of elements and mesh size, were also presented. the tpb specimen of astm a533 steel material was used in the assessment study on fcg under different loading conditions, such as cyclic, variable and random loadings. therefore, the emphasis in this study was more on the assessment of fcg under variable and random loadings, based on three different fcg models, namely, the austen, modified forman and nasgro. it is important to note that different models give different fatigue lives. in order to validate these results, a set of experiments were performed under the same boundary conditions and they were then compared with the predicted values. more importantly, a good agreement was found between the findings in the present study and those in the previous research. the regression technique was used and shown by the polynomial equations for each set of the experiments and the comparison revealed discrepancies as a result of different loading conditions. among the factors affecting the fcg rate were initial crack length, stress ratio, aspect ratio and load sequence. the results also showed that increasing the initial crack length, stress ratio and aspect ratio would tend to minimise the fatigue life. for the cases of the load sequence effect, the number of blocks and the stress ratio has significantly affected the crack growth rate. refrences fatemi, a. & yang, l. 1998. cumulative fatigue damage and life prediction theories: a survey of the state of the art for homogeneous materials. international journal of fatigue 20(1): 9-34. hamam, r., pommier, s. & bumbieler, f. 2007. variable amplitude fatigue crack growth, experimental results and modelling. international journal of fatigue 29: 1634-1646. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 422 msc. fatigue. 2005. user manual. los angles: msc. software corporation. ncode. 2003. user guide manual. ice-flow cracks growth. v 2.0. molent, l., mcdonald, m., barter, s. & jones, r. 2008. evaluation of spectrum fatigue crack growth using variable amplitude data. international journal of fatigue 30: 119-137. paris, p.c., tada, h. & donald, j.k. 1999. service load fatigue damage-a historical perspective. international journal of fatigue 21: s35-s46. richard, h., sander, m., fulland, m. & kullmer, g. 2008. development of fatigue crack growth in real structures. engineering fracture mechanics 75: 331-340. simonsen, b.c. & tornqvist, r. 2004. experimental and numerical modeling of ductile crack propagation in large-scale shell structures. marine structures 17: 1-27. schijve, j.1999. the significance of fractography for investigations of fatigue crack growth under variable amplitude fatigue. fatigue fracture engineering material structures 22 :87-99. schijve, j. 2003. fatigue of structures and materials in the 20th century and the state of the art. international journal of fatigue 25: 679-702. skorupa, m. 1999. load interaction effects during fatigue crack growth under variable amplitude loadinga literature review part ii: qualitative interpretation. fatigue fracture engineering material structures 22(10): 905-926. skorupa, m. 2001. load interaction effects during fatigue crack growth under variable amplitude loadinga literature review. part 1: empirical trends, part ii: qualitative interpretation. fatigue fracture engineering materials structures 21: 987-1006. stephens, r.i., fatemi, a., stephens, r.r. & fuchs, h.o. 2001. metal fatigue in engineerring. 2nd edition. new york: j. wiley & sons. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 422 figure 1.2: three models of cracking source: anderson 2005 figure 1.3: a finite element mesh of a shell structure al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 424 figure 1.5: display of constant and random loading histories figure 1.4: integration grid points of the tet10 nodes case 2 case 1 figure 1.6: display of the load histories with different two sequences al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 422 figure 1.7: contour displays of stresses on shell structure figure 1.8: the fcg worksheet based on the glyphwork softwaresource: ncode 2003 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 422 figure 1.9: fatigue crack growth using different models figure 1.10: fatigue crack growth rates for various tpb specimen geometries based on different fcg models ∆k (mpa. m 1/2 ) 0.001 0.01 0.1 1 d a /d n (m m /c y c le ) austen model mod. forman model nasgro model al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 1 natural frequencies behavior of a cantilever composite beam with embedded shape memory alloy wires by dr. qasim abbas atiyah department of mechanical engineering, university of technology dr_qasim_uot@yahoo.com received 17 september 2014 accepted 25 november 2014 abstract: recently, shape memory alloys (smas) has been on the forefront of research. smas are unique alloys in that they can remember an original shape after being deformed. they have been used for a wide variety of applications in various fields. the natural frequencies have been identified as one of the most critical parameter in vibration study which may lead to structure failure during resonance. in present work, an analytical solution for the calculation of natural frequencies of composite cantilever beams with embedded sma wires was studied. the beams were clamped at one end and free in other end. a mathematical model is developed to describe the behavior of the natural frequencies of a cantilever composite beam embedded by sma wires and solved by using matlab program. the natural frequencies found from the analytical were compared with previous research and got a good agreement error. it was found that the natural frequencies of beams decreased with increasing the number of embedded sma wires at a temperature below martensite temperature transformation and increased with increasing the number of embedded sma wires at a temperature above austenite finish transformation. some geometrical factors and mechanical properties were studied in this work, such as width of beam, thickness of beam, length of beam, diameters of sma wires, modulus of elasticity of glass fiber epoxy, and austenite ratio in sma wires. increasing these factors caused increasing in the natural frequencies of composite beam while the increase of length of beam resulted in decreasing in natural frequencies. key words: composite beam, shape memory alloy, vibration characteristics. دراست تصرف التردداث الطبيعيت لعتبت حذيت هركبت هذعوت بأسالك سبائك راكرة الشكل م.د قاسن عباش عطيت الجاهعت التكنولوجيت / قسن الهنذست الويكانيكيت الخالصت : ها حيث فريدة من نوعالسبائك ذاكرة الشكل خصائص مقدمة البحوث الحديثة وذلك بسببفي بحوث سبائك ذاكرة الشكل تعتبر وبسبب كون الترددات . ومختلفة تطبيقات واسعةفي وهذه الميزة جعلتها تستخدم انها تعود الى شكلها األصلي بعد تعرضها للتشوه الحل التحليلي لحساب ايجادفي هذا العمل فقد تم الهياكل نتيجة حدوث الرنين.من العوامل المؤثرة على فشل ةالطبيعية واحد al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 2 وهذه العتبة تكون مثبتة لعتبة حدية مصنوعة من مادة مركبة مقواة بأسالك مصنوعة من سبائك ذاكرة الشكلالترددات الطبيعية . النتائج تم األخرى وقد تم تطوير الحل تحليلي اليجاد تلك الترددات بأستخدام برنامج ماثالبنهايتيها وحرة من النهاية من احدى مع وقد وجد في هذا البحث ان الترددات الطبيعية انخفضت. ونسبة خطأ مقبولة ةقة جيدبواعطت مطامقارنتها مع أبحاث سابقة وازدادت مع زيادة عدد االسالك المارتنسايت درجة التحول الكلي لطور دون زيادة عدد االسالك المقواة عند درجة حرارة ست بعض انعىامم انشكهيت مج دساح كزنك .المدعمة عند درجة حرارة اعلى من درجة التحول الكلي الى طور االوستنايت نمادة األساط معامم انمشونتو ئك راكشة انشكمباسمك قطش سهك انخذعيم نسو سمك انعخبتو نعخبتاانهنذسيت مثم عشض وانخىاص ث انخشدداقيم سبب صيادة في ينالنياف انضجاجيت ونسبت طىس االوسخنايج في اسالك انخذعيم. وقذ وجذ بان صيادة قيم هزه انعىامم صيادة طىل انعخبت في حناقض قيم انخشدداث انطبيعيت. جانطبيعيت نهعخبت. بينما سبب هفاتيح الكلواث: العتبت الوركبت , سبائك راكرة الشكل , خصائص االهتسازاث notations: ms : martensite starts temperature upon cooling; mf : martensite finish temperature upon cooling; as : reverse transformation start temperature upon heating; af : reverse transformation finish temperature upon heating. : modulus elasticity : coefficient of thermal expansion of the composite beam, : the coefficient of the thermal expansion of the sma wires e : the tensile modulus. i : cross-sectional moment of inertia. : mass per unit area. : natural frequency of the beam. 1. introduction: sma possesses an interesting property by which the metal remembers its original size or shape and reverts to it at a characteristic transformation temperature. sma alloys change phase (between martensite and austenite) at certain critical temperatures, and therefore they display different stressstrain characteristics in different temperature ranges [1]. they attracted much attention in recent years, since they are smart materials, as well as functional materials, which already exist. in the last decade, the development of smart composite materials and structures has become an attractive research topic in an area of materials science and engineering. smart structures involve embedded smart material actuators as well as microprocessors. the structures are able to respond to external commands or locally change in conditions, with control achieved by actuators applying localized strains or stresses [2]. 2. literature review: in recent years, many literatures have reported the use of embedded sma actuators for composite beams. the embedded sma actuators could induce an additional bending moment, in order to provide an additional strength to the composite beams. lau and et al. [3] presented an analytical model for the evaluation of natural frequencies of glass fibre composite beams with embedded shape memory alloy (sma) wires. the beams were clamped at both ends, and different numbers of sma actuators were embedded at an interlayer of the composite beams. the authors studied the changes of tensile modulus, internal recovery of stress and strain, and stresses due to the thermal expansion of the beams, wires. they found that the natural frequencies of composite beams decreased with increasing the number of embedded sma actuators at a temperature below martensite finish temperature and at a temperature above austenite finish temperature. and, the al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 3 natural frequencies of the beams with low sma wire fraction initially decreased and then increased with increasing the number of sma wires. lau [4] studied a common type of sma actuator, nitinol wires embedded into advanced composite structures to modulate the structural dynamic responses, in terms of natural frequency and damping ratio by using its shape memory and pseudo-elastic properties. he introduced a theoretical model to estimate the natural frequency of the structures before and after actuating the embedded sma wires and measured the damping ratios of different sma composite beams through experimental approaches. tan et al. [5] studied the fundamental frequency of hybrid composite plate embedded with the sma wire using impact hammer testing on different boundary conditions. they showed that the results of the fundamental frequency and damping ratio for the hybrid composite plate were shifted and were dependent on the heat level applied to the wires and the boundary conditions of the plate. sato et al. [6] investigated the vibration characteristics of symmetric carbon fiber reinforced plastics (cfrp) laminates with embedded shape memory alloy fibers for passive vibration control by tailoring the laminate configuration. they studied using two in-plane lamination parameters in addition to four out-of-plane lamination parameters, the shape memory effect on the fundamental frequencies for the case of simply supported edges. yuvaraja and senthilkumar [7] studied the vibration control of glass fiber reinforced plastics (gfrp) flexible composite beam using shape memory alloy (sma). they measured the tip displacement of the beam to study the extent of vibration control and developed a mathematical model to describe the behavior of the composite. birman and rusnak [8] presented the mathematical formulation of the vibration control mechanism that combines an effective continuous elastic foundation representing the support provided by sma wires to the structure with the energy dissipation as a result of the hysteresis occurring in the wires. they obtained a closed form expression for the loss factor in large aspect ratio plates supported at the mid-span by a system of parallel sma wires. yuvaraja and senthilkumar [9] presented the sma based and pzt based composites for investigating the vibration characteristics. a smart beam consisting of a glass fibre reinforced polymer (gfrp) beam in cantilevered configuration with externally attached smas was modeled. the authors investigated the vibration suppression of smart beam by using ansys and evaluated experimentally the vibration control of flexible beam for first mode. barzegari et al [10] evaluated the numerical-based analysis for the natural frequencies and mode shapes of the plate with embedded shape memory alloy wires. they modeled plates in according to the classical plate theory (cpt) as well as first-order shear deformation plate theory (fsdt) and sma wires as a beam. the effect of axial load generated by sma wires due the change of temperature on the natural frequencies was studied. most of the previous researches have not found an exact solution for the cantilever composite beam embedded by sma wires, and some important factors which effect on the behaviour of the natural frequencies have not studied enough. therefore, a new calculation approach to find the exact solution for determination the natural frequencies is investigated in this work. also, some parameters which affected on the vibration properties, such as length of beam, width of beam, thickness of beam, diameter of embedded sma wires, the ratio of austenite phase in that wires, and modulus of elasticity of glass fiber epoxy are studied in this research. 3. theoretical approach: considering the beam shown in figure (1), the cantilever beam is clamped in one end and free in other end, the sma wires are embedded into the beam’s longitudinal direction, the fourth order differential equation for the lateral vibration of the beam is [3]: (1) al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 4 where: (2) (3) the general solution of equation (1) is [4]: (4) where: [( ) ] (5) [( ) ] (6) and: [ ] [ ] (7) [ ] [ ] (8) [ ] [ ] (9) boundary conditions: the boundary conditions for cantilever beam are: 1) (i.e. at clamped edge) (10) 2) (i.e. at free edge) (11) from the first boundary conditions: (12) (13) and from the second boundary conditions: [ ] [ ] (14) [ ] [ ] (15) but eqs. (12) & (13) in eqs. (14) & (15) get: al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 5 [ ] * + (16) [ ] * + (17) re-arranging eqs. (16) & (17) (18) (19) i.e., eqs. (18) & (19) can be written in matrix form: | | * + * + (20) the phase transformation tensor ω can be expressed as functions detail expression of the relationship of the martensite fraction ξ and applied temperature, t for the martensitic transformations. { [ ] } (21) , [ ] (22) the tensile modulus and coefficient of thermal expansion of the sma materials can be evaluated by using the mixture law, i.e., (23) (24) the modulus and density can be determined as follow: [ ] (25) [ ] (26) the natural frequency of the composite cantilever beam embedded by sma wires can be determined by solving the above matrices, the general forms of solutions after considering the boundary conditions in equations (10) & (8), the analytical solutions for evaluating the natural frequency of the composite beams, are [11]: ( ) √ (27) where are small correction terms, and obtianed as: al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 6 the correction in the higher modes tend to zero rapidly, and can be neglected. 4. results and discussions: in the present work, niticcu and glass fiber epoxy are used as sma wires and composite beam material respectivelly. the mechanical properties of sma material and epoxy are illustrated in table (1). the dimensions of samples are listed in table (2), these samples are used for comparsion between the present numeircal results and results of ref. [4], as shown in table (3). this table shows a good agreement between present results and experimential results of ref. [4], espically in samples beam3wm, beam-5wm, and beam-3wa, the error in these samples is less than 1%. also, there is a small error is between present results and numerical results of ref. [4], especially in samples beam1wm, beam-3wm, beam-5wm, beam-3wa, and beam-5wa. figures (2), (3) & (4) show the behavior of changing the natural frequencies with no. of embedded wires in composite beam at two cases, first in sma wires fully in martensite phase ( i.e., ) and second in sma wires fully in austenite phase (i.e., ). in these figures, the values of natural frequencies in all modes decreased when the number of sma wires incresed in martensite phase transformation, and the natural frequencies increased when the number of sma wires increased. the first three natural frequencies decreased by 5.759% when the embedded sma wires increased from one wire to 19 wires in martensite phase, and the first three natural frequencies increased by 2.129% when the embedded sma wires increased from one wire to 19 wires in austenite phase. figure (5) depicts the relation between the natural frequencies of composite material and length of beam. the behaviour of changing in the first three modes is logarithmic, when the length increased from 200 to 440 mm, the first three natural frequencies decreased by 79.338%. the relation between the width of beam and values of natural frequencies is shown in figure (6). in this figure, when width increased, the values of natural frequencies in all modes are increased too. the natural frequencies increased by 2.09% when the width increased from 20 mm to 40 mm. figure (7) manifests the relation between the thickness of beam and values of natural frequencies, this figure shows when the thickness of beam is increased, the natural frequencies highly increased, therefore the values of natural frequencies increased by 157.42% when the thickness is just increased from 1 mm to 2.5 mm. the relation between the diameters of sma wires with natural frequencies is clarified in figure (8). in this figure, when the diameter is increased, the values of natural frequencies of embedded composite beam decreased. the natural frequencies decreased by 14.45% when the diameter of embedded wired is increased from 5 mm to 15 mm. figure (9) shows the relation between the austenite phase ratio in composite beam in embedded wires of sma and the values of natural frequencies of beam, the value of temperature in beam controls this ratio of austenite phase, when this ratio is increased, the natural frequencies increased. therefore, the natural frequencies increased by 5.03% when the austenite ratio is increased from 0% to 100% in embedded sma wires in composite beam. finally, the relation between the stiffness of composite beam and natural frequencies is illustrated in figure (10). in this figure, when the stiffness of the glass fiber epoxy of composite beam is increased, the natural frequencies increased. the value of natural frequencies increased by 66.04% when the value of stiffness is increased from 10 gpa to 30 gpa. 5. conclusions: in the present work, a numerical solution for the natural frequencies of composite beam embedded by sma wires is evaluated. good agreement errors with pervious experimental and numerical results are found. the natural frequencies of beams decreased with increasing the number of al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 7 embedded sma wires at a temperature below martensite temperature transformation and increased with increasing the number of embedded sma wires at a temperature above austenite finish transformation. the increasing in the width of beam, thickness of beam, diameters of sma wires, modulus of elasticity of glass fiber epoxy, and austenite ratio in sma wires caused an increase in the natural frequencies of composite cantilever beam. the increase in the length of beam resulted in a decrease in natural frequencies of beam. references: 1) m. senthilkumar, 'analysis of sma actuated plain flap wing’, j. of eng. science and technology review, 2012, vol. 5, pp. 39-43. 2) kazuhiro otsuka and xiaobing ren, 'recent developments in the research of shape memory alloys', elsevier, intermetallics, vol. 7, 1999, pp. 511-528. 3) kin-tak lau, 'vibration characteristics of sma composite beams with different boundary conditions', elsevier, materials and design, vol. 23, 2002, pp. 741–749. 4) kin-tak lau, li-min zhou, and xiao-ming tao, ' control of natural frequencies of a clamped– clamped composite beam with embedded shape memory alloy wires', elsevier, composite structures, vol. 58, 2002, pp. 39–47. 5) w. tan, s. jamian, m. ghazali and n. mohamed, 'fundamental frequency of hybrid composite plate embedded with shape memory alloy wire ', computational and experimental mechanics, 2007, pp. 286-294. 6) masaki sato, hideki sekine, and yuichi hayakawa, ' vibration characteristics of cfrp laminates with embedded shape memory alloy fibers', department of aeronautics and space engineering, tohoku university, 2009. 7) m. yuvaraja, and m. senthilkumar, ' vibration control of gfrp composite beam using sma-flexional actuators', international j. of eng. vol. 8, 2010, pp. 289-295. 8) victor birman and ian rusnak,' vibrations of plates with super elastic shape memory alloy wires ', j. eng. math., 2011. 9) m. yuvaraja and m. senthilkumar, 'comparative study on vibration characteristics of a flexible gfrp composite beam using sma and pzt actuators', manuf. and ind. eng., vol. 11, 2012, pp. 28-33. 10) m. barzegari1, m. dardel, a. fathi1, m. pashaei, 'effect of shape memory alloy wires on natural frequency of plates', j. of mechanical eng. and automation, vol. 2, 2012, pp. 23-28. 11) p. hagedorn and a. dasgupta, 'vibration and waves in continuous mechanical systems', john wiley and sons ltd, first edition, 2007. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 8 table (1): the mechanical properties of sma material and epoxy [3] description properties type value niti (nitional) tensile modulus martensitic phase 25 gpa austenitic phace 50 gpa thermal coefficient 0.55 mpa/ o c density 6450 kg/m 3 transformation temperature martensite finish 25 o c martensite start 40 o c austenitie finish 55 o c austenitie start 48 o c glass fiber / epoxy composite tensile modulus, e1 12 gpa density 1800 kg/m 3 table (2): description of testing samples [4] samples temp. ( o c) no. of wires width (mm) length (mm) thickness (mm) beam 0 33.2 200 1.41 beam-1wm 1 33.1 200 1.44 beam-3wm 3 33.4 200 1.51 beam-5wm 5 33.3 200 1.50 beam-1wa 1 32.3 200 1.40 beam-3wa 3 33.0 200 1.44 beam-5wa 5 33.3 200 1.50 table (3): comparison between present results and experimental and numerical results of ref. [4] samples present results numerical results [4] experimental results [4] errors% with num. errors % with exp. beam 92.37907 97.22 98.63 5.24029% 6.76661% beam-1wm 94.05561 96.78 98.12 2.89657% 4.32126% beam-3wm 98.08562 96.12 98.10 2.003981% 0.01466% al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 9 beam-5wm 96.88659 95.23 97.56 1.709822% 0.69505% beam-1wa 91.83875 71.00 81.8 22.69058% 10.93084% beam-3wa 94.67465 91.00 95.5 3.881343% 0.87178% beam-5wa 98.81051 97.80 1.022673% figure (2): no. of embedded wires vs first natural frequency. 40.5 41.0 41.5 42.0 42.5 43.0 43.5 44.0 44.5 45.0 0 5 10 15 20 n a tu r a l fr e q u e n c y ( h z ) no. of sma wires martensite austenite x y figure (1): a schematic illustration of the composite beam embedded by sma wires al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 10 figure (3): no. of embedded wires vs second natural frequency. figure (4): no. of embedded wires vs third natural frequency. 255 260 265 270 275 280 285 0 5 10 15 20 n a tu ra l fr e q u e n cy ( h z) no. of sma wires martensite austenite 710 720 730 740 750 760 770 780 790 0 2 4 6 8 10 12 14 16 18 20 n a tu r a l fr e q u e n c y ( h z ) no. of sma wires martensite austenite al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 11 figure (5): length of beam vs natural frequency. figure (6): width of beam vs natural frequency. 0 200 400 600 800 1000 1200 1400 1600 1800 0.18 0.23 0.28 0.33 0.38 0.43 0.48 n a tu r a l fr e q u e n c y ( h z ) length of beam (m) first natural frequency second natural frequency third natural frequency 0 100 200 300 400 500 600 700 800 0.018 0.023 0.028 0.033 0.038 0.043 n a tu r a l fr e q u e n c y ( h z ) width of beam (m) first natural frequency second natural frequency third natural frequency al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 12 figure (7): thickness of beam vs natural frequency. figure (8): diameter of sma wires vs natural frequency. 0 200 400 600 800 1000 1200 1400 0.0008 0.001 0.0012 0.0014 0.0016 0.0018 0.002 0.0022 0.0024 0.0026 n a tu r a l fr e q u e n c y ( h z ) thickness of beam (m) first natural frequency second natural frequency third natural frequency 0 100 200 300 400 500 600 700 800 0.0004 0.0006 0.0008 0.001 0.0012 0.0014 0.0016 n a tu r a l fr e q u e n c y ( h z ) diameter of sma wires (m) first natural frequency second natural frequency third natural frequency al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 13 figure (9): austenite phase transformation vs natural frequency. figure (10): modulus of elasticity vs natural frequency. 0 100 200 300 400 500 600 700 800 900 0 10 20 30 40 50 60 70 80 90 100 n a tu r a l fr e q u e n c y ( h z ) austenite phase transformation (%) first natural frequency second natural frequency third natural frequency 0 200 400 600 800 1000 1200 1e+10 1.5e+10 2e+10 2.5e+10 3e+10 n a tu ra l fr e q u e n cy ( h z) modulus of elasticity (gpa) first natural frequency second natural frequency third natural frequency al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 014 study of scenedesmus algae growth in a splitcolum air-lift photobioreactor amer d. zmat albdiri, chemical engineering dept., college of engineering, al-qadisiyia university, ad diwaniyah, iraq. email: amer_zmat@yahoo.com. received 21 may 2015 accepted 5 july 2015 abstract the growth of scenedesmus algae, cultivated in a split-column airlift bioreactor under three different light intensities (94, 187, 468 sme ./ 2  ) and two values of superficial gas velocities (0.3, 1 cm/s), was investigated. the physical properties of the culture medium were monitored by various analytical methods (optical density, chlorophyll concentration). samples were taken twice a day (10:00 am and 5:00 pm) for cell count and optical density measurements. the dynamic growth rate of the algae was studied using the integrated three-state fluid dynamics model developed by eilers and peeters (1988). the kinetic parameters for the system under defined light/dark cycles were evaluated. the obtained results indicate that the growth rate and chlorophyll content of the scenedesmus algae directly proportional to light intensity and superficial gas velocity. keywords: algae growth, photobioreactor, biomass production, dynamic growth rate باستخدام مفاعل بيو ضوئي ذو الرفع الهوائي scenedesmusدراسة نمو طحالب االنقسامي الملخص: باستخدام مفاعل بيو ضوئي من نوع عمود الرفع الهوائي االنقسامي تحت scenedesmusتم دراسة نمو طحالب sme 468 ,187 ,94)ظروف مختلفة من الشدة الضوئية ./ 2  . تم رصد ,(cm/s 1 ,0.3)وسرع غاز سطحية ( وتقييم الخصائص الفيزيائية للوسط باستخدام طرق تحليلية مختلفة )الكثافة الضوئية وتركيز الكلوروفيل(. تؤخذ عينات مساء( ألغراض قياسات الكثافة الضوئية وعد الخاليا. تم دراسة معدل 0:11صباحا و 01:11الفحص مرتين يوميا ) ام موديل ديناميكية االطوار الثالثة التكاملي الذي طور بواسطة الباحثين باستخد scenedesmusالنمو الحيوي لطحالب eilers and peeters (1988) اظهرت النتائج ان معدل النمو لطحالب .scenedesmus يتناسب طرديا مع الكثافة الضوئية لمصدر االضاءة وسرعة الغاز السطحية. introduction microalgae can be cultivated in open systems (ponds) or in controlled closed systems (photobioreactors). a photobioreactor can be described as an enclosed, illuminated culture vessel designed for controlled biomass production. photobioreactors, despite their costs, have several major advantages over open systems. photobioreactors minimize contamination, and offer better control over conditions such as ph, temperature, light, and co2 concentration. mailto:amer_zmat@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 011 the microalgae biomass yield, and consequent hydrocarbon production, is many times superior to that of higher plants due to the shorter algal life cycle and their more efficient growth. these organisms are not only excellent sources for biofuels (yielding ~50 times more biodiesel than soybeans per acre) due to the high lipid content (up to 40 80%) of some strains, but they consume co2 and nox while abating environmental pollution (processing wastewater as a nutrient source while producing o2), and the biomass can be used in pharmaceutical products, for food additives, aquaculture, single cell proteins, etc. (becker, 1994; vonshak & guy, 1992; kulick, 1995). although research and development to advance these potential uses has grown in recent years, the commercialization of microalgae technologies use for biofuels and bio-based chemicals production and beneficial co2 and waste water treatment is still in its early stages due to the complexity of the algae culturing processes and the lack of understanding. as one scales-up in size, problems become more related to engineering than biology, and the hydrodynamics and transport characteristics of the media, reactor and process play a greater role (olaizola, 2000). the availability, intensity and duration of the light exposure can be major factors controlling productivity and hence the efficiency of co2 fixation (lee and low, 1992; merchuk et al., 1998). the growth of the strain dunaliella parva is stimulated when the provision of light is interspersed with periods of darkness (oren and shilo, 1982). those previous results confirm that only the light harvesting (lh) phase requires light, the rest of the photosynthetic process does not. however, present models succeeded to predict algae growth in pbrs, relies on volume average irradiance (iav), and estimate specific photosynthetic growth rates (μ) by empirical correlations that relate μ with iav (aiba, 1982; evers, 1991; rorrer et al., 1999; molina grima et al., 1996). these models are inherently unable to consider light gradients, light fluctuation whether motion or source induced, photoinhibition and photolimitation and the effects of fluid movement. to overcome such shortcomings, eilers and peeters (1988) proposed a mechanistic dynamic growth model which has been extended by wu and merchuk (2001) to include a maintenance constant, me, to account for the cellular damage as a function of the shear stress. luo (2005) and luo and al-dahhan (2011) demonstrated that the apparent viscosity of the media measured during the algae growth changes with time, but unfortunately their work did not account for such changes. based on luo's (2005) measurements, it has been found that the growth of microalgae in split-column airlift photobioreactor outperforms draft tube air-lift and bubble columns bioreactors. therefore, split-column air-lift photobioreactor was used to further advance the development of the new multi-scale modeling approach. the aim of this study is to use a split-column air-lift photobioreactor for culturing a scenedesmus sp. algae under two superficial gas velocities (0.3, 1 cm/s) and three irradiance intensities (94, 187, 468 sme ./ 2  ). the growth rate of the cultured algae is then estimated based on optical density and cell count measurements. dynamic growth rate model for photobioreactor performance the dynamic growth rate model developed by luo and aldahhan (2004) integrates the physiology of photosynthesis and microorganism growth, the flow dynamics, and the irradiance distribution within the reactors for photobioreactor performance evaluation. this model uses the three state photosynthesis model proposed by eilers and peeters (1988) to describe the photosynthetic kinetics as shown in figure (1). wu and merchuk, 2004 suggested a model to calculate the residence time of an algae cell inside each part of the draft tube photobioreactor (the riser, the downcomer and the separator) based on overall gas holdup. the model concluded what is called the cyclic light history of cells in the draft tube photobioreactor as shown in figure (2). however, albdiri et al, 2015 showed that overall gas holdup cannot appropriately represent the dynamic behavior of the split-column airlift al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 014 photobioreactor and local gas holdup considerably varies from riser to downcomer and from the bottom to the top of the column as well. unfortunately the cyclic light history model (light/dark) is not applicable for the split-column airlift photobioreactor. both riser and downcomer experience the same light exposure. hence, light/dark cycle was performed through setting the lighting to rotating 6-hour periods of light and dark as shown in figure (3). materials and methods the microalgae secendesmus sp. utex 1590 was the microalgae used. the culture was obtained from the collection of the university of texas, austin, usa. the inoculum for the photobioreactors was grown indoors under artificial light. nutrient requirements are salts, nitrates, phosphorus, carbon source, and air. ideally, food should contain minimal carbon content to allow for carbon dioxide (no more than 3% for this strain) to be the primary carbon source. current food source is algal supplement proline f1/f2 fed 1ml/gal every monday, wednesday, and friday while not on co2 supplement and 1-2 times a week while on co2 feed. tanks are stirred manually at least every other day to ensure the algae doesn’t settle out and to make diffusion of nutrients throughout the system as even as possible. air flow rate was set to 2500 ml/min with adjustments being made to incorporate co2 doping of the air feed of percentages between 1.5 and 3 percent for this particular strain; however, the air feed was set to 4000 ml/min when no co2 doping is present to allow co2 from the natural filtered air to be sufficient to support algal growth. care was taken to monitor ph since the incorporation of co2 in the water lowers ph outside of long-term tolerance ranges. ph tolerance range for long term is 6.8 to 8.2. the best growth is achieved when ph is maintained between 7.0 and 7.5. lighting source is 3 x 6500k t5 fluorescent lamps placed 12-18 inches above growth tanks and approximately 3 ins apart to ensure even lighting across the growth tanks. the light timing is set to match the cycles simulated in reactor. two-week lead-time was adjusted to the light/dark ratio before tests been run in the reactor in order to achieve consistent results. the lighting was set to rotating 6-hour periods of light and dark. the photobioreactor and culture medium the split-column airlift photobioreactor used in this study is shown schematically in figure (4). the column was made from plexiglas with an inner diameter of 13 cm and height of 150 cm. a plexiglas plate divides the reactor into two zones of equal cross-sectional areas. the liquid volume of the reactor is 15 liters. the top clearance (the distance from the top edge of the splitting plate to the static liquid level) was 3 cm while the bottom clearance was 5 cm. at the bottom of the riser section of the photobioreactor, a sparger figure (4-b) was installed at the center of the riser. the column has 5 ports for measurement (p1 through p5 in the figure) on both sides (riser and downcomer). these ports are at heights of 29.90cm, 52.00 cm, 76.05cm, and 100.1 cm (equivalent to 4.6r, 8r, 11.7r, 15.4r) respectively. before each experiment, the whole column was carefully washed with soap water and thoroughly rinsed with deionized water. a cotton plug was provided to purify the compressed air before it enters the column through the ring sparger, and the column was loosely covered by a lid. the compressed air, enriched with 3% co2 (merchuk et al., 2000), was introduced into the reactor through the ring sparger, providing both carbon source and agitation for the photobioreactor. light energy was supplied continuously by a bank of cool white sylvania fluorescent lamps (four 40watt lamps with an intensity of 3000 lumen and eight 60w high output lamps with an intensity of 3281 lumen) evenly distributed around the airlift column. such configuration of the lamp bank, generated a fairly uniform light intensity distribution around the al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 014 illuminated column surface. the lighting was set for rotating 6-hour periods of light and dark. after the airlift column photobioreactor was inoculated with scenedesmus sp., the optical density of the culture was initially very low (less than 0.01). to avoid photoinhibition and to shorten the lag time, the cells need to be adjusted to the new environment. the reactor was first run for 12 hours at low light intensity and at low superficial gas velocity (i.e., illuminated only by the room lamps without switching on any bank lamps, photon flux densities (pfd) was around 26 μe/m2s and the superficial gas velocity was 0.3 cm/s). then, four 40w lamps were switched on while keeping the same superficial gas velocity, giving a pfd around 275 μe/m2 s on the illuminated surface. after the optical density of the culture reached 1.0, the number of lamps to be switched on, was increased and controlled, giving high irradiance (i.e., up to 468 μe/m2 s). finally, to test the effect of mixing intensity on the airlift column photobioreactor performance, the superficial gas velocity was increased to 1cm/s while keep all lamps on. analytical methods a 5 ml pipette was used for sample preparation. the pipette was carefully cleaned and sterilized before it was inserted into the top part (where mixing is perfect) of the photobioreactor for sampling. each sample was divided into two parts; the first was usually used for optical density measurements, while the second sample was used for cell count measurements. the cuvette was cleaned and sterilized before it was used for optical density measurements, and the cell count chamber was used for the cell count measurements. optical density optical densities of the algae samples were measured at least twice a day (10:00 am and 5:00 pm). a spectrophotometer (uv-visible genesys 10) and cuvettes with path length of 1cm were used for the measurements at wavelengths of 680, 666, 656, and 648nm. for each optical density measurement, an average of three samples was taken as the real optical density. cell number counting cell numbers were counted using a counting chamber (bright-line counting chamber, fisher healthcare) under a microscope (olympus 324, olympus inc.) with 400× zoom. concentration of chlorophyll the chlorophyll content was estimated by the method of liu et al. (1981). optical density was measured at 648, 656 and 666 by using uv-visible spectrophotometer (uv-visible genesys 10). the chlorophyll a and b content was calculated using the following equations (maraskolhe, et al (2012)): ca (μg ml -1 ) = 13.7 a666 nm 5.76 a648 nm (1) cb (μg ml -1 ) = 25.8 a648 nm 7.60 a666 nm (2) ca+b (μg ml -1 ) = 1000/(39.8 × a656 nm (3) ph measurements ph measurements were carried out twice a day using hi991001 waterproof ph meter to monitor the effect of co2 consumption by algae culture and consequently the algae growth rate in the splitcolumn airlift bioreactor. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 010 results and discussion effect of superficial gas velocity on scenedesmus sp. growth the growth rate of scenedesmus algae, expressed as cell number vs. cultivation time, for two different superficial gas velocities (0.3 and 1.0 cm/s) and under (94 µe/m 2 .s) light intensity is shown in figure (5). it appears that the growth rates were similar during the initial phase (< 2 days) of cultivation for both superficial gas velocities. then, the growth rate of the higher superficial gas velocity (1 cm/s) diverged from the lower superficial gas velocity (0.3 cm/s) with a 25% increase. the growth of the culture experienced a slight growth of algae. this followed the expected pattern of a lag phase, during which algae needs to become established. during the initial stage of the exponential phase of the growth of algae (days 2-4), it was observed that the growth rates under different superficial gas velocities were identical. this is due to low rate of growth (0.04 h -1 ) as the culture was exposed to low light intensity in avoidance to photo inhibition. the divergence between the growth rates on day 4 was attributed to the effect of mixing on the growth rate of algae. the mixing enhances the chance of algae to be directly irradiated. since the mixing rate at a superficial gas velocity of 1 cm/s is higher than that of 0.3 cm/s, the growth rate of algae will be higher as well. the growth rate at the exponential phase ranged from (0.209 h -1 for 0.3 cm/s to 0.285 h -1 for 1 cm/s). this large difference in growth rate reflects the importance of increasing the superficial gas velocity to perform better mixing and consequently higher growth rate. however, higher superficial gas velocities usually cause higher hydraulic force (shear stress) which may break microorganism cells. luo and al-dahhan (2005) found that a superficial gas velocity of 1 cm/s is a tolerable velocity. effect of light intensity on scenedesmus sp. growth figure (6) shows the dependence of the growth rate of scenedesmus algae on the light intensity provided by the bank of cool white sylvania fluorescent lamps surrounding the photobioreactor column. during the initial phase of cultivation, the growth rate of algae was found to be similar for all light intensities (94, 187, 468 µe/m 2 .s). however, during the exponential phase of the growth of scenedesmus algae, the growth rate under light intensity (468 µe/m 2 .s) begins to significantly depart (approximately 31%) from that of light intensities (94, 187 µe/m 2 .s), whereas a slight difference in the growth rate values under 94 and 187 light intensities was noticed in favor of the light intensity 187 µe/m 2 .s (13% difference). the cultivation was carried out at a superficial velocity of (1 cm/s). the interpretation of the above large difference in the growth rate of algae under the light intensity 468 µe/m 2 .s may be attributed to the abundant light energy available for the photosynthesis of algae. this confirms the fact that the higher the light intensity, the higher penetration depth of light inside the photobioreactor at high culture density of algae. however, no photo inhibition was noticed when applying 468 µe/m 2 .s light intensity. evolution of the chlorophyll content of scenedesums sp. algae the build-up of the chlorophyll a and chlorophyll b contents of scenedesums sp. algae is shown in figures (7,8). the results show that the evolution of both chlorophyll a and chlorophyll b follows the same trend of the evolution of the cell count of scenedesums sp. algae shown in figure (5). however, the evolution of chlorophyll was found to be highly dependent on the light intensity. approximately 100% increase in chlorophyll evolution was observed under higher light intensity (i = 468 µe/m 2 .s). a moderate gain in chlorophyll content was observed during this study in comparison to maraskolhe's work (2012). this may be due to lower concentration of carbon dioxide (3%) when compared to maraskolhe's work (10-36%). however, these results are consistent with the conclusion of lue and al-dahhan (2005). they concluded that split-column photobioreactor demonstrates light stress to cultured algae due to its high performance of mixing (high frequency of wall visits by the cultured algae). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 014 conclusions the growth rate of scenedesums sp. algae was found to be substantially dependent on superficial gas velocity. the higher the superficial gas velocity, the higher mixing intensity and the higher growth rate of algae. however, critical shear stress of algae must be considered and not exceeded when designing for high superficial velocities. light intensity was also found to have a direct effect on the growth rate of algae, but, the photo inhibition must be avoided when applying light source for culturing algae. although, the growth rate of scenedesums algae increases with higher superficial gas velocities, but, the chlorophyll content was found to grow at lower rate due to the light stress that may be caused by the high frequency of wall visits of the algae. acknowledgment the financial support of the department of state, crdf global through the iraq scientists fellowship program (isfp) is gratefully acknowledged. the author would like to acknowledge the support of the chemical and biochemical engineering department missouri university for science and technology. also, the invaluable guidance of this research by prof. muthanna aldahhan who host me as isfp fellow is sincerely appreciated. thanks are due to aastha ojha (phd student at the research group of prof. al-dahhan) for her help during the course of this research. notations x: biomass concentration (µg/ml) x1: fractions of the reaction centers in the resting state x2: fractions of the reaction centers in the activated state x3: fractions of the reaction centers in the inhibited state i: instant light intensity exposed to the cells α, β,  ,  : photosynthetic reaction constants ca : chlorophyll a content cb : chlorophyll b content ca+b : chlorophyll a and chlorophyll b contents refrences aiba, s. 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(1999), "production of bioactive metabolites by cell and tissue cultures of marine macroalgae in bioreator systems", in plant cell and tissue culture for the production of food ingredients. new york: kluwer academic/plenum. s. a. khan, r. rashmi, m. z. hussain, s. prasad, and u. c. banerjee, (2009) “prospects of biodiesel production from microalgae in india,” renewable and sustainable energy reviews, vol. 13, no. 9, pp. 2361–2372. vinod r. maraskolhe, ashish r. warghat2, guru charan and p. b. nandkar, (2012), " carbon sequestration potential of scenedesmus species (microalgae) under the fresh water ecosystem", african journal of agricultural research vol. 7(18), pp. 2818-2823 wu x. and merchuk j.c. (2002). simulation of algae growth in a bench-scale bubble column reactor. biotech. bioeng.. 80(2), 156-168 wu x. and merchuk j.c. (2001). a model integrating fluid dynamics in photosynthesis and photoinhibition processes. chem. eng. sci. 56, 3527-3538 wu, x. and merchuk, j.c. (2004) simulation of algae growth in a bench scale internal loop airlift reactor. chemical engineering science, 59, 2899-2912. xiaoxi wu and jose c. merchuk (2001), "a model integrating fluid dynamics in photosynthesis and photoinhibition processes", chem. eng. sci. 56, 3527-3538. xiaoxi wu and jose c. merchuk (2002), " simulation of algae growth in a bench-scale bubble column reactor", chemical engineering science, volume 80, issue 2, 156–168. xiaoxi wu and jose c. merchuk (2004), " simulation of algae growth in a bench-scale internal loop airlift reactor", chemical engineering science,59, 2899-2912. http://onlinelibrary.wiley.com/doi/10.1002/bit.v80:2/issuetoc al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 014 figure (1): the structure of the three states model proposed by eilers and peeters (1988) (duplicated from wu and merchuk, 2001). a photosynthetic reaction center in state x1 captures a photon and passes to the reactive state, x2, at a rate proportional to the light intensity, i. the reaction center in state x2 can either return to state x1 at a constant rate,  , or capture another photon and reaches the inhibited state x3. at state x3, the reaction center returns to state x1 at a constant rate,  . the chain of dark reactions is started by the direct passage of x2 x1. figure (2): cyclic light history of cells in airlift photobioreactor. (duplicated from xiaoxi wua and jose c. merchuk, 2004 ) . figure (3-a): light history of cells in figure (3-b): light history of cells in split-column airlift photobioreactor split-column airlift photobioreactor 6-hours light on period. 6-hours light off period. figure (3): cyclic light history of cells in split-column airlift photobioreactor. separator is, ts downcomer i, t riser i, t separator is, ts riser i, t downcomer i,t al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 014 optical probe 1 0 0 .1 c m 2 9 .9 0 c m p1 p2 p3 p4 p5 pressure air 13 cm 1 0 5 c m 7 6 .0 5 c m 5 2 c m 13 cm a/d unit and computer figure (4– a): split-column (p1-5: ports 1-5) figure (4b): sparger al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 044 figure (4c): configuration of the lamps to illuminate the reactor. figure (4): schematic representation of split-column airlift bioreactor, sparger and bank of illuminating lamps. figure (5): effect of superficial gas velocity on the growth of scenedesums sp. algae in a split-column airlift photobioreactor. 0 1 2 3 4 5 6 7 8 9 0 2 4 6 8 10 12 c e ll c o u n t x 1 0 ^ -6 time, days evolution of the cell count ug=0.3 cm/s ug=1.0 cm/s al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 041 figure (6): effect of light intensity on the growth of scenedesums sp. algae in a split-column airlift photobioreactor (superficial gas velocity equals to 1 cm/s). figure (7): evolution of the chlorophyll content of scenedesums sp. algae in a split-column airlift photobioreactor (i = 94 µe/m 2 .s and superficial gas velocity = 1 cm/s). figure (8): evolution of the chlorophyll content of scenedesums sp. algae in a split-column airlift photobioreactor (i = 468 µe/m 2 .s and superficial gas velocity = 1 cm/s). 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 c e ll c o u n t x 1 0 ^ -6 time, days (i = 94 µe/m^2.s) (i = 187 µe/m^2.s) (i = 468 µe/m^2.s) 0 1 2 3 4 5 0 2 4 6 8 10 12 ch lo ro p h y ll c o n te n t time, days evolution of chlorophyll content chlorophyll a chlorophyll b 0 1 2 3 4 5 6 7 8 9 0 2 4 6 8 10 12 ch lo ro p h y ll c o n te n t time, days evolution of chlorophyll content chlorophyll a chlorophyll b neural dynamic programming for optimal al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 102 neural dynamic programming for optimal control of large genetic regulatory networks ahmad t. abdulsadda communication department al-najaf technical college technical educational foundation of iraq abstract: the modeling and control of genetic regulatory networks carries tremendous potential for gaining a deep understanding of biological processes, and for developing effective therapeutic intervention in diseases such as cancer. a dynamical programming control has been proposed for determining an optimal intervention policy to shift the steady-state distribution of the network. the dynamic programming solution is, however, computationally prohibitive for large gene regulatory networks, as its complexity increases exponentially with the number of genes. since the number of genes considered is directly related to the accuracy of the model, it is imperative to be able to design optimal intervention policies that can be reasonably implemented for large gene regulatory networks. to this endeavor, we will design a neural dynamic programming controller to optimize the same dynamic programming performance measure, while requiring only a polynomial time complexity. the proposed neural dynamic programming structure includes two networks: action and critic. the critic network is trained toward optimizing a total reward to objective, namely to balance the bellman equation. the action network, constrained by the critic network, generates the optimal control strategy. both the control strategy and the critic output are updated according to an error function that changes from one step to another. general theory of non-homogeneous markov chain will be used to find the optimal strategies of non uniform policy method. keywords: genomic signal processing (gsp) , boolean network structure, neural dynamic programming networks (ndp), bellman optimal equation. برمجة العصبية الحيوي لفي التحكم األمثل لشبكات كبيرة التنظيمية الوراثية احمد طه عبد الساده جبار .د :الخالصة النمذجة والتحكم في الشبكات التنظيمية الوراثية يحمل إمكانات هائلة الكتساب فهم عميق من العمليات البيولوجية، والتدخل ل السرطان. وقد تم اقتراح برمجة التحكم الديناميكي لتحديد سياسة التدخل األمثل العالجي لتطوير فعالية في أمراض مث al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 103 لتحويل توزيع ثابتة للدولة للشبكة. الحل البرمجة الديناميكية، مع ذلك، باهظة حسابيا لشبكات الجينات التنظيمية الكبيرة، ا مباشرا على عدد من الجينات التي تعتبر دقة وتعقيدها يزيد أضعافا مضاعفة مع عدد من الجينات. منذ يرتبط ارتباط النموذج، ال بد أن تكون قادرة على وضع سياسات التدخل األمثل التي يمكن تنفيذها بشكل معقول لشبكات الجينات التنظيمية لديناميكية، الكبيرة. في هذا المسعى، ونحن تصميم العصبية البرمجة الديناميكية تحكم لتحسين أداء نفس اإلجراء البرمجة ا في حين ال تتطلب سوى تعقيد الوقت متعدد الحدود. هيكل المقترح العصبية البرمجة الديناميكية تضم اثنين من الشبكات: العمل والناقد. يتم تدريب نحو تحسين شبكة الناقد مكافأة إلجمالي الهدف، أال وهو تحقيق التوازن في المعادلة المنادي. شبكة الناقد، يولد استراتيجية التحكم األمثل. يتم تحديث كل من استراتيجية السيطرة وإخراج الناقد وفقا لوظيفة العمل، مقيدة شبكة من الخطأ أن التغييرات خطوة واحدة إلى أخرى. وسوف تستخدم النظرية العامة للسلسلة ماركوف غير متجانسة للعثور على استراتيجيات األمثل لألسلوب غير سياسة موحدة. introduction genomic signal processing (gsp) is the engineering discipline that studies the processing of genomic signals. genomic signals must be processed to characterize their regulatory effect and their relationship to changes at both genotype and phenotype levels. gsp contains different methodology involving detection, prediction, classification, control, statistical, and dynamical modeling of gene networks. let's give the reader some basic idea about the natural operation for human cells, and how they are replicating by cell division, and irreparably damaged cells remove themselves by process called apoptosis. each cell contains biological instruction called dna and must be replicated and handed down unchanged to the cells progeny when it divides. each cell could make copy from dna, which is called rna and the final stage generates another protein type called the messenger mrna. what a designer needs to figure out is that if the gene express (it is on) there is protein, otherwise the cell does not express (the gene is off) and there is no protein generated. these processes occur in the natural condition with the healthy person. control process inside the cells depends on complex interaction between the products of the cell and those environments. as might be expected from a highly complex, efficient and survivable system, control is highly distributed and redundant. any uncontrolled process inside the cells causes uncontrolled divide in them. from a translational perspective, the ultimate objective of genetic regulatory network modeling is to use the network to design different approaches for affecting network dynamics in such a way as to avoid undesired phenotypes, such as, cancer [1]. recently, in the hardware side there are new equipments, they did convert the information code from the genotype to binary information, one of those strategies is the micro-array strategy used to obtain the binary and ternary gene expression in discrete case (quantization process) is generically called probabilistic boolean networks (pbns), [2-4]. the basic pbns structure introduced by kauffman [5-7] to allow the incorporation of uncertainty into the inter-gene relationships. any given pbn should have a state transition matrix or transition probability to move from one state to another. the process control for this dynamic state matrix can be studied in the context of homogeneous markov chains with finite state space. basically, the major goal of functional genomics is to screen for genes that determine specific cellular phenotype (disease) and model their activity. engineering therapeutic tools involves nonlinear dynamical networks, to characterize gene regulation, and developing intervention strategies to modify dynamical behavior. intervention studies have used three different approaches to deal with problem: (i) resetting the state of the pbn to a more desirable initial state [3] ; (ii) changing the steady-state (long run) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 104 behavior of the network by minimally altering its predicator function[4]; (iii) manipulating external (control) variables that alter the transition probabilities of the network[8]. in [8]they proposed control method, dynamic programming is employed to finite a finite horizon control sequence intervention. in [9], they solved the bellman dynamic programming using infinite horizon control (there was not needed to know the terminal state information). basically, in the two methods of [8] and [9] is well known that the direct application of optimal control methods is limited by the size of the state space-the curse of dimensionality. for larger biological models involving interactions among many genes, a stochastic control method has been polynomial time complexity. recently, there is a group in university of texas [13], they formulated the problem of controlling a context sensitive pbn as a markov chain with reward. the refinement learning method (q learning) was used to find the optimal strategies. although the q learning method deals with a larger genetic problem, it is still suffering from lengthy calculation time. it took two days to find the optimal strategies for a problem had 15 genes coded in binary form. nidhal and at el [14-17], have been proposed an optimal perturbation control scheme to solve the dynamic equation, we thought this scheme still consuming a lot of time to do the calculation. in this paper, we proposed a novel method using neural dynamic programming controller to optimize the same dynamic programming performance measure, while requiring only a polynomial time complexity. the proposed neural dynamic programming structure includes two networks: action and critic. the critic network is trained toward optimizing a total reward to objective, namely to balance the bellman equation. the action network, constrained by the critic network, generates the optimal control strategy. both the control strategy and the critic output are updated according to an error function that changes from one step to another. general theory of non-homogeneous markov chain will be used to find the optimal strategies of non uniform policy method. simulation has been conducted to examine the effectiveness of the proposed scheme. the remainder of the paper is organized as follows. problem formulation: the definition of boolean networks, general control process strategies, and solution using dynamic programming in section 2. dynamic neural programming (dnp) structure was described in section 3. section 4, contains the results of the control strategies process. finally, section 5 conclusion. problem formulation boolean network structure the context-sensitive probabilistic boolean networks pbn consists of a set v = {x1,…, xn}, of n nodes ,where xi ε {0,1,…,d-1}, and a set {f1,f2,…,fk} of vector-valued functions, called predictor functions. in the framework of gene regulation, each xi, for i= 1… n, represents the expression value of a gene. it is common to mix terminology by referring to xi as the i th gene. each vector valued function f1 which has the form of fl = (fl1,…,f1n), determines a constituent network of the context-sensitive pbn. the context sensitive pbn with control can be modeled as a stationary discrete time dynamic system: ),,()1( kkk wuxfkx  (1) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 105 where for all k, the state xk is an element of a space s, the control input uk is an element of space c, the wk is disturbance in the space d. finally, f : s ×c ×d → s. in the particular case of context sensitive pbns of n genes composed of n boolean networks with perturbation probability p and network transition probability q, s =[ 0,1,2,…,2 n -1], where n numbers of gene. the control signal uk should be in space c =[0,1,2,…,2 m -1],where m is the number of control inputs. another equivalent way to represent the dynamical system in (1) is as a finite state markov chain described by the control dependent one step transition probability pij(uk), where for any k =0,1,2,…,n ; i,j ε s and u ε c: )u ,()( k1 uixjxpu ij p kkk   . (2) the one-step evolution of the probability distribution in the case of a pbn containing 2 n states with control inputs can be described with following equation [8, 9]: )( 1 kkk uapdpd   . (3) where pdk is the 2 n dimensional state probability distribution vector at time k, and a(uk) is the 2 n × 2 n matrix of control dependent transition probabilities ,i.e., a(uk) is the matrix whose ij th element is pi-1,j-1 (uk). equation (3) represented the main point in our work, because if the system starts with any initial state probability vector, it could end with the desired one depends on the probability transition matrix and the input control. solution using dynamic programming the optimal control problem can now be stated as follows: given an initial state x(0), find a control law π ={u0,u1,…,um-1} that minimizes the cost functional           1 0 ))(())(,())0(( m k mkkkk mxcxuxcexj , subject to the constraint   )(pr 1 kijkk uaixjx   . (4) where aij(uk) is the i th row, j th column entry of the matrix a(uk). optimal control problems of the described by equation (4) can be solved using the technique of dynamic programming. the dynamic programming solution to eq.(4) was derived in [10, 11]: ))(())(( mxcmxj mm  ,   .2 ..., 1,2,i 1;-m ..., ,2 ,1 ,0,).(),()( n 2 1 1 2,...,2,1 min             kjuauxcxj n m k j kkijkkk u kk (5) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 106 where cm (x(m)) is the terminal cost at terminal state x(m), m is the finite number of steps. note that the expectation on the right hand side of equation (5) for each xk and k:   1 2 1 11 )(),(     kk j ijkkkk juauxxje n . (6) thus, the final solution of the dynamic programming system (equation (4)), which is known as bellman equation is given as [10, 11]   .2,...,2,1;1,...,2,1,0,).(),()( )),(())(( 2 1 1 2,...,2,1 min n j kkijkkk u kk mm imkjuauxcxj mxcmxj n m k              (7) neural dynamic programming the objective of a dynamic neural programming controller is to optimize a desired performance measure by learning to create appropriate control action through interaction with the environment the controller is designed to learn to perform better over time using only sampled measurement and with no prior knowledge about the system. figure 1 shown as a schematic diagram of neural dynamic programming (ndp) online learning control scheme, which has two main neural networks, the action and the critic networks. to be more quantitative, consider the critic network shown in figure 2, the output of the critic element is the objective function j, which represented approximates the discounted total rewardto-go. specifically, it approximates rk at time k. it can be calculated as: ... 21   kkk rrr  (8) where rk is the future accumulative reward-to-go value at time k, γ is a discount factor for infinite horizon problem (0 < γ <1), since the exact value for the discount factor is given by: 1 1   r  (9) where r is the external reinforcement value at time k, rk+1 is the external reinforcement value at time k+1. before go deeply in critic and action networks details, let's defined the ultimate function u and reinforcement rk. the ultimate function is the only source of information the adaptive process (adp) has about the task for which it is designing the controller. when the statement is made that dynamic programming designs an optimal controller, optimality is defined strictly in terms of the ultimate al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 107 function. it is important to recognize that a different u function will (typically) yield a different controller. so that, in our case we defined it as: 0 u if 0 1u if 1      u (10) as we mentioned before, the reinforcement signal r is used to find the critic error which referred the adaptive error the adjusted the weights of critic network depend upon the back propagation principle. if deal with state probability vector we can define the following reward per stage function    m k kk pd pdpd r k max * , (11) where pd * k is a desired probability distribution vector, pdk current distribution vector. in practice, the reward values will have to mathematically capture the benefits and costs of intervention and the relative preference of probability state, and have to set by physicians in accordance with their clinical judgment, [9]. action-critic neural networks structure generally, the neural dynamic programming provides a suitable structure to solve the dynamic programming equation exactly like the bellman equation. so that ndp aims to find the optimal objective function: 1 **  kkk jrj  (12) based on figure 2, the predication error of the critic network is calculated as: )()( 1 kkkc rjjke    , (13) )( 2 1 )( keke cc  , (14) where ec is the mean square error for critic network. this error provides the desired objective function for critic network to minimize by tuning critic weights. principles used in the weight update for the critic can be derived through gradient decent as below: i h i cic pwkbj    1 22 )( , (15) where al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 108 h 1,2,...,i ; 1 1     iq i e p , (16) and   h1,2,.....,i ];[][ 11 jxijwbq cci . (17) the weight and bias update in critic networks are given as: )()()1( kbkbkb ccc  , )()()1( kwkwkw ccc  . (18) depending on back propagation algorithm, we have driven the exact values of the following biases and weights:  hidden to output bias and weights h,1,2,...,j ;][)(][][ ,)(][][ 2 1 2 2 1 2     kcckckc cckckc jpkeljwjw keljbjb   (19)  input to hidden bias and weights     h.1,2,...,j1,n1,2,...,i x[j];)][1(p[i][i])(][][ ,)][1(p[i][i])(][][ kk 21 1 1 kk 21 1 1     kccckckc kccckckc ipwkeljwjw ipwkeljbjb   now, we investigate the adaptation in the action network shown in figure 3. in action neural network the input layer has n input (probability distributed state vector) and one output node which represent the control uk. the associated equations for the action network are: , 2 1 )( ,)( aa ka eke ujke   ,m1,2,...,i ;][][][v[i] m,1,2,...,i ; 1 1 ][ 1 22 k ][        h j kaa ivk jgijwib e iu k (20) (21) (24) (23) (22) (25) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 109        n i kaa ihk ixjiwib e jg k 1 11 k ][ h1,2,...,j ;][][][h[i] h,1,2,...,j ; 1 1 ][ the weight and bias update in action networks are given as: )()()1( kbkbkb aaa  , )()()1( kwkwkw aaa  . (27) the update rule for the nonlinear mlp action network also contains two sets of equations:  hidden to the output nodes in output layer bias and weights  input to hidden layer simulation results we apply the proposed neural dynamic programming control to a probabilistic boolean network derived from gene expression data collected in a study of metastatic melanoma [8]. the abundance of mrna for the gene wnt5a was found to be highly discriminating between cells with properties typically associated with high versus low metastatic competence. furthermore, it was found that an intervention that blocked the wnt5a protein from activating its receptor, the use of an antibody that binds the wnt5a protein, could substantially reduce wnt5a’s ability to induce a metastatic phenotype [8]. this suggests a control strategy that reduces the wnt5a genes action in affecting biological regulation. a seven-gene probabilistic boolean network (pbn) model of the melanoma network containing the geneswnt5a, pirin, s100p, ret1, mart1, hadhb, and stc2 was derived in [8-10]. figure 4, derived in [8-10], illustrate the relationship between genes in the human melanoma regulatory network. note that the human (26) (28) (29) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 110 melanoma boolean network consists of 2 7 = 128 states ranging from 00 … 0 to 11 …1, where the states are ordered as wnt5a, pirin, s100p, ret1, mart1, hadhb, and stc2, with wnt5a and stc2 denoted by the most significant bit (msb) and least significant bit (lsb), respectively. we observer that the states from 0 to 63 have wnt5a down regulated (which means 0) and hence are desirable states, as compared to states 64 to 127 have wnt5a up regulated(which means 1) and hence undesirable. the steady state distribution of human melanoma network of the original and controlled networks is shown in figure 5. we can observe that the probability distributed state vector shifted from unwanted states (65-127) to the wanted states (0-64) that was our goal. the mean square error for both action and critic network is shown in figure 5 (c), which is shown obviously how the action and critic weights are convergence. figure 5: simulation results : (a) 2d-steady-state distribution results; (b) steady-state distribution of gene-activity profile after intervention with optimal control policy using ndp method; (c) ndp mean square error. discussion we have formulated the ndp strategy to find an approximate stochastic control policy for a context sensitive pbn. ndp not only lowers computational complexity in comparison to the optimal stochastic control, but performs virtually the same as the optimal stochastic control when the learning duration is long enough. as shown in the melanoma case, applying suboptimal policy has the same effect in reducing the likelihood of visiting undesirable states, the ones with high chance of metastasis in the long run. the time complexity of the approximate control method is polynomial, whereas the time complexity of the optimal control algorithm is exponential in the number of genes. acknowledgments the author would like to thank dr. ranadip pal from texas tech. university for providing the human melanoma gene regulatory network dataset. also, the author would like to thank dr. nidal bouaynaya and dr. kameran iqbal from university of arkansas at little rock for helping. [1] datta, a., pal, r., and dougherty, e.r.: 'intervention in probabilistic gene regulatory networks', current bioinformatics, 2006, 1, (2), pp. 167-184. [2] shmulevich, i., dougherty, e.r., and zhang, w.: 'gene perturbation and intervention in probabilistic boolean networks', bioinformatics, 2002, 18, (10), pp. 1319-1331. [3] shmulevich, i., dougherty, e.r., and zhang, w.: 'control of stationary behavior in probabilistic boolean networks by means of structural intervention', biol. syst., 2002, 10, (4), pp. 431-446. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 111 [4] shmulevich, i., dougherty, e.r., kim, s., and zhang, w.: 'probabilistic boolean networks: a rule-based uncertainty model for gene regulatory networks', bioinformatics, 2002, 18, (2), pp. 261-274. [5] kauffman, s.a.: 'metabolic stability and epigenesis in randomly constructed genetic nets', j. theor. biol., 1969, 22, (3), pp. 437-467. [6] kauffman, s.a.: 'the origins of order: self-organization and selection in evolution' (oxford university press, 1993, 1st edn.). [7] kauffman, s.a., and levin, s.: 'towards a general theory of adaptive walks on rugged landscapes', j. theor. biol., 1987, 128, (1), pp. 11-45. [8] datta, a., choudhary, a., bittner, m., and dougherty, e.r.: 'external control in markovian genetic regulatory networks', mach. learning, 2003, 52, (1/2), pp. 169-191. [9] pal, r., datta, a., and dougherty, e.r.: 'optimal infinite-horizon control for probabilistic boolean networks', ieee trans. signal process., 2006, 54, (6), pp. 2375-2387. [10] bertsekas dp,' dynamic programming and optimal control' athena scientific 1995; 1 and 2. [11] bertsekas, d.p.: 'dynamic programming and optimal control' (athena scientific, 1995, 2005, 3rd edn.) [12] bertsekas, d.p., and tsitsiklis, j.n.: 'neuro-dynamic programming' (athena scientific, 1996, 1st edn.). [13] faryabi b., datta a. ,and e. r. dougherty:' on approximate stochastic control in genetic regulatory networks', iet syst.,2007 ,1,(6),pp. 361-368. [14] x. qian, datta, a., pal, r., and dougherty, e.r.: 'intervention in probabilistic gene regulatory networks via greedy control policies based on long run behavior', bmc system biology, 2009, pp. 147-154. [15] nidal b., and roman s.: 'optimal perturbation control of general topology molecular networks', ieee transaction on signal processing, 2011, pp.1-15. [16] nidal b., and roman s.: 'inverse perturbation for optimal intervention in gene regulatory networks', bioinformatics, 2011, pp.103-1011. [17] nidal b., m. rasheed, and roman s.: 'intervention in general topology gene regulatory networks', ieee proc. genomic signal processing, 2011. [18] nidal b., and roman s.: 'method for optimal intervention in gene regularity networks', ieee signal processing magazine, 2012, pp.1053-1088. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 112 figure 1: schematic diagram for implementation of ndp, lines without sold represent the forward path, sold dash lines represented the back update weight path. figure 2: nonlinear (sigmoid activation function) critic neural networks structure: n+1 input nodes in input layer, h nodes in a one hidden layer, one node in the output layer. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 113 figure 3: nonlinear action neural networks structure: n input nodes in input layer, h nodes in a one hidden layer, m nodes in the output layer. figure 4: the probabilistic boolean networks of the seven genes, [8]. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 114 (b) (a) ( c ) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 963 suggested model to estimate sediments transport in aldiwaniyahh river based on field and laboratory investigations dr. thulfikar razzak alhusseini dr. haider ali almussawy department of civil engineering, department of environment engineering college of engineering, college of engineering, university of alqadisiyah. university of almustansiriyah received 20 april 2015 accepted 5 july 2015 abstract in this paper an experimental (field and laboratory) study was conducted on measuring the amount of suspended sediment transport in aldiwaniyah river and introducing a new formula to estimate sediments transport in this river. the application of this study required the selection of 25 sections along the river and its branches and the hydraulic parameters of these sections as well as the slope of bed were measured, and many samples from the river were taken to the laboratory. samples of suspended sediment in water were taken at each section in the river and analyzed in the laboratory. a new formula was introduced using the dimensional analysis and datafit 9.1 software corresponding to the field and laboratory measurements in this study. the results were compared with other formulas such as engelund – hansen, laursen, and einstein formulas and indicate a good exception. keywords: suspended sediment, sediment transport. اقتراح موديل لتخمين انتقال الرسوبيات في نهر الديوانية باالعتماد تحريات حقلية ومختبرية د. حيدر علي مهدي الموسوي د. ذوالفقار رزاق عبد المهدي الحسيني قسم الهندسة البيئية, كلية الهندسة , الجامعة المستنصرية قسم الهندسة المدنية, كلية الهندسة , جامعة القادسية الخالصة وتم اقتراح معادلة )حقلية ومختبرية( لقياس كمية حمل الرسوبيات العالقة في نهر الديوانية في هذا البحث تم عمل دراسة عملية حيث تم وتفرعاته مقطع موزعة على النهر 52. ان تطبيق هذه الدراسة تطلب اختيار جديدة لتمثيل انتقال الرسوبيات بذلك النهر ومن ثم تم اخذ عينات للمختبر لغرض قياس تركيز قاع النهر انحدارقياس المتغيرات الهيدروليكية لهذه المقاطع باالضافة الى . تم اخذ عينات ماء حاوية على الرسوبيات العالقة بكل مقطع من النهر وتم تحليلها مختبريا. تم تقديم معادلة جديدة سوبياتالر باالعتماد على البيانات الحقلية والمختبرية في هذه الدراسة لنهر الديوانية وتم datafit 9.1البرنامج التحليل البعدي وباستخدام .( engelund – hansen, laursen, and einsteinادالت اخرى مثل )مقارنة النتائج مع مع 1introduction sediments play an important role in elemental cycling in the aquatic environment. for the purposes of aquatic monitoring, sediment can be classified as deposited or suspended. deposited sediment is that found on the bed of a river or lake. suspended sediment is that found in the water column where it is being transported by water movements. suspended sediment is also referred to as suspended matter, particulate matter or suspended solids. generally, the term suspended solids refers to mineral plus organic solids, whereas suspended al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 973 sediment should be restricted to the mineral fraction of the suspended solids load. the study of river suspended sediments is becoming more important, nationally and internationally, as the need to assess fluxes of nutrients and contaminants to lakes and oceans, or across international boundaries, increases. one of the most serious environmental problems is erosion and the consequent loss of topsoil. camenen and larson developed a bed load transport formula for non cohesive sediment based on the bed – shear concept of meyerpeter and muller and validated for steady flows, oscillatory flows, and combined steady and oscillatory flows [1]. alkizwini et. al. studied the total sediment transport in kirkuk irrigation channel by selecting 24 sections along this channel and samples of the laden water taken from each section and then present a formula to estimate the total load in this irrigation channel [2]. mizuyama et al measured the suspended load and wash load in mountain torrents using tubidometry and / or direct sampling [3]. alkseevskiy et. al. analysed in his paper the interrelation between erosion, sediment transportation and accumulation proposed by n. i. makkaveyev (1908–1983) and its further development in modern studies of river channel processes in russia [4]. diplas et. al. explained the methods of sediment transport measurements in rivers [5]. kisi proposed in his paper the application of evolutionary fuzzy models (efms) for suspended sediment concentration estimation. the efms are improved by the combination of two methods, fuzzy logic and differential evolution. the accuracy of efms is compared with those of the adaptive neurofuzzy, neural networks and rating curve models. the daily stream flow and suspended sediment data belonging to two stations, quebrada blanca station and rio valenciano station, operated by the us geological survey (usgs) are used as case studies. the mean square errors and determination coefficient statistics are used for evaluating the accuracy of the models. based on the comparison of the results, it is found that the efms give better estimates than the other techniques [6]. esteves et. al. undertake a field measurements of longshore sediment transport (lst) on barred and non-barred beaches composed of fine, medium and coarse sands in brazil, denmark and portugal. measurements and predictions of vertical suspended sediment concentration profiles (cprofiles) and cross-shore hydrodynamic parameters were then combined in a new semi-empirical model for prediction of lst (ltmod). instantaneous lst predictions from lt-mod and wellknown bulk lst formulae were compared. tests using lt-mod to simulate measured changes in shoreline position in southern brazil for periods of c. two years showed that lt-mod gave more accurate predictions than existing bulk lst formulae. results indicate that lt-mod may have practical utility at sites where access to equipment is limited and where reliable estimates of lst are required over extended periods[7]. tarazon et. al. introduced a paper and examined the relations between rainfall, runoff and suspended sediment transport in the isábena basin during a quasiaverage hydrological year. the isábena is a mesoscale river basin that drains a mountainous area comprising patches of highly erodible materials (badlands). the paper includes an analysis of the different hydrological and sedimentary responses of the catchment to a similar rainfall [8]. chegini pender explored a laboratory study to determine the influence of current uniform flow conditions on bed load of different small size sediment particle beds and its bed formations. the influence of uniform flow and its related near bed turbulent flow conditions on bed load sediment transport and its related bed form in relatively low, mild and steep slopes channel has been experimentally investigated. four sediment particle sizes were evaluated in the experimental study: (1) fine sand (0.2 mm), coarse sand (1.6 mm), very coarse sand (2.8 mm), and fine grain (4.4 mm). a traditional experimental technique was developed to enable accurate performance for sediment particle transport measurement. the technique of estimating the transport rate of sediment particles is based on the trap measuring device [9]. xue et. al. used a coupled wave–ocean–sediment transport model to hindcast coastal circulation and fine sediment transport on the mekong shelf in southeastern asian in 2005. comparisons with limited observations showed that the model simulation captured the regional patterns and temporal variability of surface wave, sea level, and al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 973 suspended sediment concentration reasonably well [10]. claudi et. al. used three methods to estimate river bed load discharges were compared in a large sand–gravel bed river. the unit and total bed load transport rates estimated by sediment sampling, dune tracking method and the equations of van rijn and meyer-peter and müller were compared. the analysis was based on a large data set obtained from field surveys that combined sediment sampling, acoustic doppler profiler (adp) measurements, and multi-beam echo soundings of the middle reach of the river loire (france) for contrasting flow conditions ranging from low flows to 2 year floods. for transport stages between 2 and 6 (i.e. between the annual mean discharge and the discharge for a 2year flood), the tested equations predicted fairly well the unit and total bed load discharges and roughly estimated the temporal variability of the bed load during floods. for these transport conditions, the best agreement with the sediment sampling measurements was observed with the van rijn formula. for lower flow conditions, the tested formulas provide lower estimates than those sampled [ 11]. khanchoul et al. introduced a methodology to predict sediment loads in the kebir drainage basin (681 km 2 ). the methodology is developed by a conventional sediment rating curve and a multiple regression model. the former method is investigated with the mean discharge classes derived from the recorded instantaneous suspended sediment concentrations and water discharges for the kebir basin, prior to the mexa reservoir construction. the latter is based on rock type erodibility, mean annual runoff and basin area variables, and which is applied for the ungauged mexa reservoir basin located upstream of the kebir gauging station (651 km 2 ) [12]. sibetheros et. al. presented a study of sediment transport in a complex mediterranean watershed consisting of temporary flow tributaries and karstic springs. both daily data and monthly sediment concentration data were used to calibrate the modified soil and water assessment tool (swat) model, designed to simulate the hydrology, sediment yield, and water quality of ungagged watershed [13]. armijos et. al. measured the suspended sediment transport in the amazon river of peru and studied the crust evolution [14]. haddadchi et. al. conducted a field experiments on total load transport in the chelichay river basin, a mountainous catchment (1,400 km 2 ) located in north eastern of iran, to evaluate total load formulas including four gravel bed rivers and a sand bed river (qaresoo river). gravel bed rivers in chelichay river basin can be grouped into two types; steep slope rivers with high shear values (chehelchay river and khormaloo river) and mild slope rivers with low shear values (narmab river and soosara river). two depth integrating suspended load samplers (dh-48 and d-49), and two bed load samplers (helley-smith and blsh) were used to measure total load [15]. termini applied in his work a 1-d numerical model, which includes a new expression of the so-called “adaptation coefficient”, to test its capability to simulate the transient bed profiles. specifically, the model has been applied to predict bed level changes due to sediment overloading and sediment cut-off. the model’s application to literature study cases (used by other researchers to assess coupled models) has shown that it gives reasonable results and, thus, it appears suitable for practical applications [16]. mouri et. al. showed through the field measurements revealed that suspended sediment behavior and fluxes decreased along the mainstream sukhaya elizovskaya river from inflows from a tributary catchment located in the volcanicmountain range. in his laboratory experiments, water samples collected from tributaries were mixed with those from the mainstream flow of the sukhaya elizovskaya river to examine the cause of debris flow and characteristics of suspended sediment in the mainstream. the experimental results were up scaled and verified using field measurements. his results indicate that the characteristics of suspended sediment and river discharge in the sukhaya elizovskaya river can be attributed primarily to the beginning of snowmelt in volcanic tributaries of the lahar valley, suggesting a significant hydrological contribution of volcanic catchments to in stream suspended sediment transport [17]. wilkinson et.al. developed a time – stepping sediment budget model for assessing land use impacts in large river basins [18]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 975 the aim of this study is to measure the sediments transport through measuring the hydraulic parameters in aldewaniya river and introducing a new formula to estimate that sediments in this river. 2types of sediments transport sediment transport is a direct function of water movement. during transport in a water body, sediment particles become separated into three categories: suspended material which includes silt + clay + sand; the coarser, relatively inactive bed load and the saltation load. suspended load comprises sand + silt + clay-sized particles that are held in suspension because of the turbulence of the water. the suspended load is further divided into the wash load which is generally considered to be the silt + clay-sized material (< 62 μm in particle diameter) and is often referred to as “fine-grained sediment”. the wash load is mainly controlled by the supply of this material (usually by means of erosion) to the river. the amount of sand (> 62 μm in particle size) in the suspended load is directly proportional to the turbulence and mainly originates from erosion of the bed and banks of the river. in many rivers, suspended sediment (i.e. the mineral fraction) forms most of the transported load [19] . bed load is stony material, such as gravel and cobbles, which moves by rolling along the bed of a river because it is too heavy to be lifted into suspension by the current of the river. bed load is especially important during periods of extremely high discharge and in landscapes of large topographical relief, where the river gradient is steep (such as in mountains). it is rarely important in low-lying areas [19]. measurement of bed load is extremely difficult. most bed load movement occurs during periods of high discharge on steep gradients when the water level is high and the flow is extremely turbulent. such conditions also cause problems when making field measurements. despite many years experimentation, sediment-monitoring agencies have so far been unable to devise a standard sampler that can be used without elaborate field calibration or that can be used under a wide range of bed load conditions. even with calibration, the measurement error can be very large because of the inherent hydraulic characteristics of the samplers and the immense difficulty with representative sampling of the range of sizes of particles in transit as bed load in many rivers. unless bed load is likely to be a major engineering concern (as in the filling of reservoirs), agencies should not attempt to measure it as part of a routine sediment-monitoring programed. where engineering works demand knowledge of bed load, agencies must acquire the specialized expertise that is essential to develop realistic field programs and to understand the errors associated with bed load measurement. due to these reasons the bed load for aldiwaniyah river can be ignored since have not a high extremely discharges, have not a steep slope, and not in a mountain area. 3sampling for suspended sediments the methods and equipment used for sampling suspended sediment are different from those used for deposited sediments. also sampling methods for measurements of the quantity of sediment in transport are different than for measurement of sediment quality. the reason for these differences reflects the fact that sediment quantity must include the sand-size fractions which are unequally distributed in depth, whereas sediment quality focuses on the silt plus clay fraction which is not depth-dependent. for bottom sediments it may be necessary to collect deposited sediments with minimum disturbance in order not to lose the fine material on the sediment surface, or because the vertical distribution of the sediment components is important (such as during establishment of historical al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 979 records or depositional rates). in deep waters this necessitates the use of grabs or corers (see also section 11.2.2), but in shallow water a scoop or spatula may be used. further discussion of the relative merits of different sampling techniques is available in water quality assessments and other relevant publications. there are four main types of samplers for suspended sediments [19]: 1-depthintegrated samplers: this sampler traverses the complete depth of the stream and back at a uniform and collected a sample which has a concentration equal to the average concentration in the vertical. 2pointintegrated samplers: it contains a sample at a desired point where it remains for a certain time. 3pumping samplers: by pumping, water can be withdrawn from a stream at a pre-determined depth. during each sampling, one liter is pumped from the stream and stored in bottle for laboratory analysis. 4continuous monitoring: this device consists of a lightemitting source and a photocell located opposite to it. the intensity of light received by the cell is affected by the presence of the suspended solid particles, which decreases the transparency of the water. the concentration of the coarser fractions of suspended sediment increases towards the bottom of the river channel. this segregation of material by particle size requires that, for the purposes of measuring quantity of suspended sediment, a depth-integrating sampling technique is used to obtain a sample that accounts for different sediment concentrations throughout the vertical profile of a water body. many types of sampler have been designed for depth-integrated sampling of suspended sediment. some are available commercially but are rather expensive. all of them have a number of features in common [19]: 1each has a water inlet nozzle and an air outlet. as the water and suspended sediment enter, air is displaced through the air outlet. 2each permits isokinetic sampling. that is, water velocity through the inlet nozzle is equal to the water velocity at the depth of the sampler. this is important for larger particles, such as sand, because the sampler would otherwise tend to overor under-estimate the amount of suspended sediment. errors caused by lack of isokinetic sampling are minimal for small particles (< 62 μm) and for practical purposes can be ignored. 3each has a metal body (for weight) that encloses a glass or plastic bottle for retaining the sample. the bottle is changed after each sample is taken. 4the diameter of the water inlet can be selected (or changed) so that the sampler will fill more or less quickly, depending on the depth of the river. in practice, depth-integrating samplers are lowered to the river bottom, then immediately raised to the surface; lowering and rising should be done at the same rate. the objective is to fill the sampler to about 90 per cent capacity; if the sampler is completely full when it emerges from the wate,r the sample will be biased because the apparatus will have stopped sampling at the point at which it filled up [19]. large, heavy samplers are usually only necessary when samples must be obtained from a bridge, boat or similar situation. in shallow streams, where all points can be reached by wading, a bucket (if nothing else is available) or a small sampler attached to a metal rod can be used. it is possible to make a simple depth-integrating sampler for use in shallow streams, using a wide-mouth, 1-litre bottle, a rubber stopper and short pieces of rigid tubing. the tubing forms the water inlet and air outlet. the lengths and diameters of the tubes may require experimentation but, in general, the air al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 973 outlet tube should be of a smaller diameter than the water inlet. the bottle is secured to a metal rod or wooden pole, then lowered and raised as outlined above. an example of a home-made sampler is shown in figure (1). the sample must be taken facing upstream so as to avoid sampling bottom sediment that was re-suspended by the operator’s feet [19]. the home – made suspended sediment sampler was designed as the specification in figure (1) and manufactured locally to measure the suspended load as an integrated sampler in aldiwaniyah river as shown in figure (2). 4measuring suspended sediment particle size distribution and concentration not only vary in the vertical section, but may also vary considerably across a river section. therefore, measuring suspended sediment concentration must take into account these variations. this becomes especially important when suspended sediment concentration is being measured for the purpose of calculating sediment load in a river. there are two generally accepted methods for measuring suspended sediment concentration for load determination as described below [19]. 4.1equal discharge increment method. this method requires first that a complete flow measurement be carried out across the cross section of the river. using the results, the cross-section is divided into five (more on large or complex rivers) increments (i.e. vertical sections) having equal discharge. the number n of increments is based on experience. depth integrated suspended sediment sampling is carried out at one vertical within each of the equal-discharge-increments, usually at a location most closely representing the centroid of flow for that increment. the sediment concentration for each equal-discharge-increment is measured as will be indicate in section 5. the mean discharge-weighted suspended sediment concentration (ssc) is obtained by taking the average of the concentration values c obtained for each interval i [19]. ssc = ∑ (1) the discharge-weighted suspended sediment load (ssl), in tons per day, for the river cross-section is obtained by multiplying the concentration, c, in ppm (mg / ℓ) by the discharge, q, in m 3 /s of each equal-dischargeincrement, i, and summing for all increments. this method is very timeconsuming, but is that most used by sediment agencies [19]. ssl = ∑ ( ) (2) 4.2equal width increment method. this method is used without making flow measurements and is usually used in small to medium rivers and especially rivers that are shallow enough for wading. the operator marks off 10-20 equal intervals across the river cross-section. at the deepest point, the operator takes a depth-integrated sample, noting the transit rate of the sampler (i.e. the uniform speed at which the sampler is lowered, then raised to the surface). using that same transit rate, a suspended sediment sample is taken at each of the intervals. because each vertical will have a different depth and velocity, the sample volume will vary with each vertical sampled. note that the bottle must never be over-filled. all samples are composited into a single container which is then agitated and sub-sampled, usually al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 972 two or three times, and analyzed for suspended sediment concentration. the average of these analyses is the mean cross sectional suspended sediment concentration. in this method, the results are corrected for differences in discharge at each section by virtue of using the same transit rate (and the same nozzle diameter) at all sections i.e. a shallow section with less discharge will produce a proportionally smaller suspended sediment sample than a deep section having greater discharge [19]. in this paper the equal width increment method is used for sampling the suspended sediment in al diwaniyah river. figure (3) shows the suspended sediment sampling from aldiwaniyah river and its branches. 5hydraulic parameters for aldiwaniyahh river and its branches the range of the hydraulic parameters which were measured for aldiwaniyah river and its branches was shown in table (1). the velocities were measured for each section using m-9 device [20] which shown in figure (4), the depths of water for each section and slopes between sections were measured using the level device, and the specific gravity diameters of particles were measured using sieve analysis in the laboratory. seven parameters were selected according to notifying many formulas that used to estimate suspended sediment load which are depth of flow h, specific gravity s.g, slope s, d65, d35, density of flow , and discharge q. 6laboratory procedures for measuring sediment concentration the sample is wet-sieved, i.e. distilled water is used to rinse the sample through the sieve. all of the water that passes through the sieve (original sample plus rinse water) is collected and filtered through a membrane filter of 0.45 μm pore size and of known weight. the sand collected on the sieve is dried and weighed [wsand (g)] and the silt and clay collected on the filter paper is dried and weighed [w clay+silt (g)]. the results can be expressed as follows [19]: concentration of sand (mg / ℓ) = (wsand / vsample) × 10 6 (3) concentration of clay + silt (mg / ℓ ) = (w clay+silt / vsample) × 10 6 (4) total suspended load (mg / ℓ) = [(wsand + w clay+silt) / vsample] × 10 6 (5) if sand concentration is not required separately, then filter a known volume of raw water through a pre-weighed 0.45 μm pore diameter filter paper. the suspended sediment concentration is then the dry weight (in grams) of the filter paper + retained sediment, minus the original weight of the filter paper, all divided by the volume (ml) of the sample, as in equation (5) [19]: the sampling of suspended sediments for aldiwaniyah river and its branches were analyzed in the laboratory and the data were obtained depending on the procedure described in paragraph 6. the following paragraph represents the dimensional analysis and generation a new formula for this river. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 976 7dimensional analysis a dimensional analysis for the selected eight parameters which effect on suspended sediment transport was done according to the flowing: f1( h (m), s.g (-),q (m 3 /s), s (-), d65 (mm), d35 (mm), qs (kg/s), ( )) = 0 (6) qs = f2 (h, s.g, s, d65, d35, , q) = 0 (7) f3 ( , , , s.g, s) = 0 (8) qs = f4 ( , , s.g, s) (9) where: qs: suspended sediment (kg/s) h: depth of water in the river (m) s.g: specific gravity of the bed river (dimensionless) s: slop of river bed (dimensionless) d 65, d 35: the size for which 65 % and 35 % of the bed material is finer, respectively (mm). : density of water ( ) q : discharge of water in the river (m 3 /s). 8datafit 9.1 software after the dimensional analysis for the selecting parameters a datafit 9.1 software is used to predict a new formula (equation 10) by trial and error of changing its formation in datafit 9.1 until obtaining a maximum correlation coefficient (r 2 )for estimating suspended load for aldiwaniyah river ( r 2 = 95 %) . figures (5) through (7) show the application of datafit 9.1 for measured data of suspended load. equation 10 can be used as a formula to estimate suspended load as well as total load since the bed load is very small compared with suspended load. qs = a.q. s + b. ( )( ) +d. ( )( ) + ( ) + m. .s (10) where: a = 1.187196 b = 432.138 c = -20147.21 d = -3.413*10 (-4) e = 11050.75 f = 10925.2 m = 1092.81 n = 17.73 the limits of formula (10) are illustrated in table (1). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 977 9comparison between new formula and other formulas the new formula was compared with other formulas such as engelund – hansen, laursen, and einstein as shown below [21]. 1einstein formula (1950): qs = 11.6 *b*u**a*[2.303 log ( ) i1+i2] (11) where: qs : suspended load (kg/sec); u*: shear velocity due to grain roughness = √ (m/sec) ; b: river width; ∆: correction factor = apparent roughness of the bed surface = ; d65: particle diameter in which 65 percent finer. the values of i1 and i2 were indicated in figures (8) and (9) in terms of fall velocity ( ) and shear velocity ( ) due to grain roughness 2laursen formula (1958): qs = q* *0.01*∑ ( ) 7/6 ( 1) f ( ) (12) where: = ( ) 1/3 values of f ( ): 1for ( ) 0.3, then f ( ) = 10.5( ) 0.24 ; where the movement is bed load 2for 0.3 2.1, then f ( ) = 3.12565( ) 2 +5.7426( )+6.0776 where the movement is suspended and bed load 3for 2.1 29 , then f ( ) = 6 f ( ) 2.1951 4for 29 160 , then f ( ) = 35223.76 log( ) – 42974.526 5for 160 , then f ( ) = 9713 f ( ) 0.2516 ; where the movement is predominantly suspended load. 3engelund – hanson formula (1967): qs = 0.05 .b. .v 2 . √ ( ) ( ) ] 3/2 (13) figures (8) and (9) show the comparisons between the new formula for aldiwaniyah river with other formulas. from figures (8) and (9) the new formula gave best results for measured data compared with the other formulas. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 973 10 – conclusions in this study a new attempt was made to measure the sediment load that transport in aldiwaniyah river and suggest a new formula based on field and laboratory investigations which were measured through this study. many samples were collected from the river and analyzed in the laboratory. from the measured data a new formula was introduced to estimate the sediment transport in that river since there is no any previous study. references [1] camenen b., and larson m., (2005), "a general formula for noncohesive bed load sediment transport", elsevier science direct vol. 63, pp. 249260. [2] alkizwini m.j., khassaf s.i., and bahjat a.n. ( 2007)," evaluation of sediment transport in kirkuk irrigation channel", engineering and technology, vol. 25, no.3, pp. 349357. [3] mizuyama t., satofuka y., laronne j., nonaka m., and matsuoka m., (2008) ; " monitoring sediment transport in mountain torrents", interpretative , conference proceeding , vol. 1, pp. 425 431. [4] alekseevskiy n.i., berkovich k.m., and chalov r.s., (2008)," erosion, sediment transport and accumulation in rivers", elsevier international journal of sediment research, vol. 23, pp. 93105. [5] diplas p., kuhnle r., gray j., glysson d., and edward t., (2008);" sedimentation engineering "; asce manual and reports on engineering practice no.110. [6] kisi o., (2009), " evolutionary fuzzy models for river suspended sediment concentration estimation", elsevier journal of hydrology, vol. 372, pp. 68-79. [7] esteves l.s., williams j.j., and lisniowski m.a., (2009)," measuring and modeling longshore sediment transport", elsevier estuarine, coastal and shelf science vol. 83, pp. 47-59. [8] tarazon j.a.t, batalla r.j, vericat d., and balasch j.c., (2010)," elsevier catena, vol. 82, pp. 23-34. [9] chegini a.h.n., and pender g., (2012);" determination of small size bed load sediment transport and its related bed form under different uniform flow conditions", wseas e-issn, vol. 8, no. 4, pp. 158167. [10] xue z., he r., liu j.p., and warner c.j., (2012), " modeling transport and deposition of the mekong river sediment", elsevier continental shelf research, vol. 37, pp. 6678. [11] claude n., rodrigues s., bustillo v., breheret j.g., macaire j.j., and juge ph., (2012), " estimating bed load transport in a large sand – gravel bed river from direct sampling, dune tracking and empirical formulas", elsevier geomorphology vol. 179, pp. 4057. [12] khanchoul k., boukhrissa z.e.a., acidi a., and altschul r., (2012)," estimation of suspended sediment transport in the kebir drainage basin, algeria ", elsevier quaternary international vol. 262, pp. 25-31. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 973 [13] sibetheros i.a., nerantzaki s., efstathiou d.,giannakiz g., and nicolaidis n.p., (2013), " sediment transport in the koiliaris river of crete", science direct , elsevier, procedia technology vol. 8, pp. 315323. [14] armijos e., crave a., vauchel ph., fraizy p., santini w., moquet j.s., arevalo n., carranza j. and guyot j.l., (2013);" suspended sediment dynamics in the amazon river of peru ", elsevier journal of south american earth sciences, vol. 44, pp. 75-84. [15] haddadchi a., omid m.h., and sdehghani a.a.,(2013), (total load transport in gravel bed and sand bed rivers , case study: chelichary watershed", elsevier international journal of sediment research, vol. 28, pp. 46-57. [16] termini d., (2014);" nonuniform sediment transport estimation in nonequilibrium situations: case studies", elsevier science direct, vol. 70, pp. 16391648. [17] mouri g., ros f.ch., and chalov s., (2014), " characteristics of suspended sediment and river discharge during the beginning of snowmelt in volcanically active mountainous environments", elsevier geomorphology vol. 213, pp. 266276. [18] wilkinson s.n., dougall c., kinseyhenderson a.e., searle r.d., ellis r.j., and bartley r., ( 2014), " development of a time – stepping sediment budget model for assessing land use impacts in large river basins", elsevier science of the total environment vol. 468469. pp. 12101224. [19] ongley e., (1996), " sediment measurements " published on behalf of united nations environment programme and the world health organization unep/who. [20] dwro, (diwaniyah water resources official ), (2014), " velocity measurement device at aldiwaniyah city" . [21] ted ch. y., (1996)," sediment transport, theory and practice", mcgrawhill co. inc. , new york. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 933 table (1): the range of the measured hydraulic parameters for aldiwaniyah river and its branches. parameters the range depth of water h (m) 1.022.57 specific gravity s.g 2.69 – 2.72 slope s 0.0001 – 0.0002 d65 (mm) 0.12 – 0.39 d35 (mm) 0.085 – 0.16 discharge q (m 3 /sec) 21.233.0 velocity v (m/sec) 0.320.93 figure (1): home – made suspended sediment sampler [19]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 933 figure (2): home – made suspended sediment sampler locally manufactured. figure (3): suspended sediment sampling in aldiwaniyah river and its branches. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 935 figure (4): the m9 device [20] figure (5): application of datafit 9.1 software for aldiwaniyah river (step 1). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 939 figure (6): application of datafit 9.1 software for aldiwaniyah river (step 2). figure (7): application of datafit 9.1 software for aldiwaniyah river (step 3). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 933 figure (8): the function i1 in terms of a (= 2d/d) for different values of z (z= ( ) [21]. figure (9): the function i2 in terms of a (= 2d/d) for different values of z (z= ( ) [21]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 932 figure (8): comparison between the new formula, measured, and other formula. figure (9): comparison between the measured, new formula, and engelund formula. 27.00 28.00 29.00 30.00 31.00 32.00 33.00 discharge q m3/s 0 8 16 24 32 40 48 56 64 72 80 88 96 104 112 120 128 136 144 152 s e d im e n t tr a n s p o rt q s k g /s measuring data present study formula laursen eq. engelundhansen eq. einstein eq. 27.00 28.00 29.00 30.00 31.00 32.00 33.00 discharge q m3/s 1 2 3 4 5 6 7 8 9 10 11 12 13 s e d im e n t tr a n s p o rt q s k g /s measuring data present study formula engelundhansen eq. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 26 behavior of permanent deformation in asphalt concrete pavements under temperature variation hanaa mohammed mahan university of babylon, college of engineering abstract rutting is recognized to be the major distress mechanism in flexible pavements as a result of increase in tire pressures and axle loads. rutting is caused by the accumulation of permanent deformation in all or some of the layers in the pavement structure. the accumulation of permanent deformation in the asphalt surfacing layer is now recognized to be the major component of rutting in flexible pavements. this is a consequence of increased tire pressures and axle loads, which subjects the asphalt surfacing layer nearest to the tirepavement contact area to increased stresses. this research evaluates information on the permanent deformation characteristics of asphalt-aggregate mixtures, with an emphasis on laboratory test techniques for measuring mixture resistance to permanent deformation. a comprehensive laboratory study was carried out using aggregate gradation for asphaltic surfacing course according with specification limit of sorb/r9, four percentage of asphalt cement were trialed in order to determine the optimum asphalt content for asphalt mixes, four levels of temperatures to accommodate the influence of temperature conditions and three levels of stresses. uniaxial creep loading strain chosen as performance test to measure the permanent deformation of asphalt mixes. the results show that the temperature has a significant effect on permanent strain and, therefore, temperatures employed for design are relatively high to reproduce the most unfavorable pavement conditions. key words: asphalt paving mixture, permanent deformation, creep test. الخالصة ظاهرة التخدد من المشاكل الرئيسية في الطرق اإلسفلتية نتيجة لزيادة في ضغطط اإلطغاراو لالومغلاو المولريغة ليتكغغلن نتيجغغة لتغغراكو التشغغلهاو الدائميغغة فغغي كغغل تل لرغغ مغغن طل.غغاو الرهغغ اإلسغغفلتي يتنغغالل هغغ ا اللوغغ الفولهاو المختلرية الالزمة ل لك دراسة لخهائص التشلهاو الدائمية في الخلطاو اإلسفلتية لاستخداو تو اختيار تدرج الركاو للطل.ة السطوية لف.ا للملاهفاو الرامغة للطغرق لالجسغلر ل الجغزت التاسغن لمغن لغين ترلغن نسب لإلسغفلو تغو جيجغاد الموتغلم ا مهغل لغا لاإلضغافة جلغ لغك تغو اخغ ترلغن درجغاو وغرارة لمررفغة ت هيرهغا لغ تغغ هير ااومغغال المختلفغغة كمغغا للينغغو النتغغائك التغغ هير الكليغغر لغغدرجاو الوغغرارة لغغ ادات التشغغلهاو الدائميغغة توغغو الخلطاو ااسفلتية ل ل ضلت لك لضرو ااستنتاجاو introduction permanent deformation in the form of rutting is one of the most important distress (failure) mechanisms in asphalt pavements. with the increase in truck tire pressure in recent years, rutting has become the dominant mode of flexible pavement failure. pavement rutting, which results in a distorted pavement surface, is primarily caused by the accumulation of permanent deformation in all or a portion of the layers in the pavement structure. rutting can also be caused by wear of pavements resulting from use of studded tires. longitudinal variability in the magnitude of rutting behavior of permanent deformation in asphalt concrete pavements under temperature variation 26 causes roughness. water may become trapped in ruts resulting in a reduced skid resistance, increased potential for hydroplaning and spray that reduces visibility. progression of rutting can lead to cracking and eventually to complete disintegration or failure. rutting accounts for a significant portion of maintenance and associated costs in both main highways and secondary roads (rabbiva garba, 2002). premature rutting in the form of shear flow of asphalt concrete, being the consequences, has directly been effecting the pavements service life, riding quality and their economic life cycles cost. true prediction of asphaltic material behaviors and their precise selection on the basis of performance can be one of the solutions towards this chaotic problem. at higher temperatures i.e. 40 °c and above, the rutting susceptibility of asphalt mixes needs to be studied in the laboratory before its laying at site. comprehensive laboratory investigation is required, to study the influence of physical and mechanical properties of aggregates on rutting resistance or the permanent deformation behavior of asphalt mixes (imran hafeez, 2009). the economics of truck transportation has caused the average gross weight of trucks to increase so that a majority of trucks are operating close to the legal axle loads limits. in countries where enforcement of the legal axle load limits is relaxed or non-existent (typical of developing countries), trucks operate at axle loads, which by far exceed the legal axle load limit. as axle loads have increased, the use of higher tire pressures has become more popular in the trucking industry. higher tire pressures reduce the contact area between the tire and the pavement, resulting in high stress which contributes to greater deformation in flexible pavements, manifested as severe wheel track rutting. as a consequence of the increased tire pressure and axle load, the surfacing asphalt layer is subjected to increased stresses, which result in permanent (irrecoverable) deformations (rabbiva garba, 2002). rutting of hot mix asphalt (hma) pavement at or near intersections is very common both in cold and hot climates. obviously, the problem is more acute in hot climates compared to cold climates because the stiffness of hma decreases with increase in pavement temperature. in most cases, there is no significant rutting in the same asphalt pavement structure away from the intersections under fast moving traffic (prithvi s. kandhal, 1998). objectives: the objectives of this study are to:  evaluate of available information about the permanent-deformation characteristics of asphalt concrete. particular emphasis is placed on methodologies which permit prediction of the amount of rutting which develops in asphalt-bound layers under the repetitive action of traffic.  describe the mechanism and problems of permanent-deformation of asphalt paving mixtures.  describe the factors which can be minimize permanent deformation in asphalt mixture and using uniaxial creep test method which is utilized to assess the resistance of asphalt mixtures to permanent deformation with variation in degrees of temperature.  describe the effect of temperatures and applied stresses on permanent deformation in asphalt mixture. permanent deformation in flexible pavement: permanent deformation in asphalt (flexible) pavements, commonly referred to (rutting and shoving ): rutting, usually consists of longitudinal depressions in the wheel paths, which are an accumulation of small amounts of unrecoverable deformation caused by each load application as shown in figure 1 (asphalt institute,1996). if an asphalt mixture ruts, it is normally because the mixture has insufficient shear strength to support the stresses to which it is submitted (sousa et al. 1991). al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 26 eisemann and hilmar studied asphalt pavement deformation phenomenon using wheel tracking device and measuring the average rut depth as well as the volume of displaced materials below the tires and in the upheaval zones adjacent to them. they concluded that: 1. in the initial stages of trafficking the increase of irreversible deformation below the tires is distinctly greater than the increase in the upheaval zones. therefore, in the initial phase, traffic compaction or densification is the primary mechanism of rut development. 2. after the initial stage, the volume decrease below the tires is approximately equal to the volume increase in the adjacent upheaval zones. this indicates that most of the compaction under traffic is completed and further rutting is caused essentially by shear deformation, i.e., distortion without volume change. thus, shear deformation is considered to be the primary mechanism of rutting for the greater part of the lifetime of the pavement. there are three mechanisms that might be involved in a rut developing, that is, plastic movement, mechanical deformation, and consolidation. plastic movement can occur either in the subgrade on which the pavement is placed, or in the asphalt concrete mixture itself. plastic movement is normally identified by a depression near the center of the applied load with slight humps on either side of the load. the distance of the humps from the center of the rut will be an indication of the depth at which the plastic movement is occurring. mechanical deformation can occur when an element under the pavement surface loses its integrity for one reason or another, and is displaced under the load. a rut resulting from this type of action will generally be accompanied by substantial pattern cracking provided the distress is allowed to progress sufficiently. a rut caused by consolidation will normally be identified by a depression in the canalized path of the applied load without an accompanying hump on either side of the depression. it occurs because the layer in which the consolidation is occurring was not sufficiently compacted during construction, and receives further densification under repeated traffic loads. it can occur either in the sub grade, in the untreated base, or in the asphalt mix itself. shoving is defined as the horizontal displacement of an asphalt mixture. there are two principal mechanisms by which shoving can occur. the first is due to instability of the asphalt mixture which results in plastic flow of the mix under horizontal thrust. the instability, and the resultant shoving under load, most frequently is because of an excess amount of asphalt binder (low air voids) which is acting as a lubricant in the mix rather than as the binder. the second mechanism that can cause shoving is slippage in the mix under horizontal thrust. in this case, the adhesion between two layers of mix is insufficient to provide the proper shear strength along the plane between the two layers. locations at which severe horizontal thrust occurs are braking areas (traffic coming to a stop sign), and uphill lanes on highways, particularly with large volumes of truck traffic. the principal contributing factor to instability in an asphalt mixture is excess asphalt content. the most common cause of a mix with insufficient shear strength is an over sanded mix, with insufficient filler, and with a low viscosity asphalt binder. asphalt pavements have a higher resistance to rapidly applied loads compared to slowly applied loads. minimize permanent deformation in asphalt mixture: the following considerations in the asphalt mix design would generally minimize the rutting and shoving (permanent deformation) problems: 1. lower asphalt content: higher asphalt content is needed for improved fatigue life and durability of the asphalt mix, but it tends to enhance the rutting and shoving problems. the mix needs to be maximized for fatigue and permanent deformation through a compromise. 2. coarser gradation: finer gradations or over sanded mixes are more susceptible to permanent deformation. 3. angular and rough textured aggregate: this is especially applicable to the fine aggregate fraction. it has been demonstrated by kalcheff and tunicliff and brown and cross that mixtures utilizing angular manufactured sand are more resistant to permanent deformation than mixes produced with rounded or sub rounded natural sand as refers by (prithvi s. kandhal, 1998) . behavior of permanent deformation in asphalt concrete pavements under temperature variation 26 4. increased air void content: mixtures with low voids in the mineral aggregate (vma) and higher asphalt contents have a tendency to have very low air void contents after densification by traffic. such mixtures lose stability after reaching a critical compaction level and start to rut and shove. 5. higher viscosity asphalt binder: an asphalt binder with a high viscosity at 60°c will be more resistant to horizontal thrust as far as plastic flow in a mix is concerned compared to a low viscosity asphalt binder. 6. higher fines content: increase in the minus 75 microns fraction of the mix will tend to stiffen (increase the viscosity) the binder. 7. larger-size aggregate: at proper asphalt content larger-size aggregate (such as 19.5 mm) mix in the wearing course tends to be more resistant to permanent deformation. 8. reduced overlay thickness: if the existing pavement is structurally sound (for example, portland cement concrete), thicker asphalt mix overlays are unnecessary in the critical areas like intersections. thinner overlays (for example, binder course can be eliminated) in these areas will minimize the problem. 9. improved bond between pavement layers: a lack of good bond between the pavement layers (especially in top 150 mm of the pavement) can cause slippage due to horizontal thrust. behavior of permanent deformation in flexible pavement researches in the history showed that rutting in the hot mix asphalt (hma) layer will generally occur within the top 3to 5-in. if a poor quality hma mixture is being used, increasing the thickness of this poor quality layer will not decrease the rutting in the hma layer. in fact, improving the material properties and mix characteristics will be significant in decreasing the rut depth (kennedy. et al, 1996). for normal cross slope values, a rut depth of 12.5 mm (0.5 inch) is typically accepted as the maximum allowable rut depth (huang, 1993 & kennedy, et al, 1996). mechanistic-empirical design guide (mepdg) has defined three distinct stages for the permanent deformation behavior of pavement asphalt materials under a given set of material, load and environmental conditions. primary stage has high initial level of rutting, with a decreasing rate of plastic deformations, predominantly associated with volumetric change. secondary stage has small rate of rutting exhibiting a constant rate of change of rutting that is also associated with volumetric changes; however, shear deformations increase at increasing rate. while the tertiary stage has a high level of rutting predominantly associated with plastic (shear) deformations under no volume change conditions as shown in figure 2 (aashto design guide, 2002). if an asphalt material is loaded with a stress that is above the flow strength of the material, at that temperature the material will start to deform (stumpf, 2007). first the material will deform rapidly, then, after some strain hardening has taken place, the material gets to a stage with a lower creep rate as shown in figure 2. this stage is known as secondary creep, or steady state creep. in the third stage the material becomes unstable and rapid collapse is the result (imran hafeez, 2009). the proportion of permanent deformation taking place is as shown in figure 2. in the different creep phases is important. the critical rut depth is generally set at 10 mm, if this depth is reached in the primary phase or in the first part of the secondary phase, the functional life of the hot mix asphalt (hma) layer is reduced drastically. in secondary phase, the rate of deformation slows down considerably. effect of temperature on permanent deformation temperature has been found to have a significant effect on rutting. hofstra and klomp (1972) determined from test-track measurements that rutting increased by a factor of 250 to 350 with a temperature increase from 68° f to140°f (20 °c to 60 °c). linden and van der heide (1987) reported a significant increase in rutting in europe during the very hot summers of 1975 and 1976. researchers have recognized the need to conduct laboratory tests at temperatures within the highal-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 22 temperature range of those encountered in the field. bonnot (1986) selected a test temperature 60°c for wearing-course asphalt concrete and 50°c for base courses. these temperatures were chosen to be relatively high to reproduce the most unfavorable conditions expected in france. similarly, mahboub and little (1988) conservatively selected the hottest pavement profile to represent critical conditions (as refers by jorge b. sousa 1991). other assumptions about the accumulation of permanent deformation in texas pavements included the following: 1) permanent deformation occurs daily over the time interval from 7:30 a.m. to 5:30 p.m.; 2) permanent deformation occurs only in the period from april to october, inclusive; and 3) permanent deformation can be ignored at temperatures below 50 °f. at the same time, it must be emphasized that the states of stress and strain caused by traffic loading also significantly influence pavement rutting. material characterization: hot mix asphalt generally consists of combination of different size of aggregates with mineral fillers, uniformly mixed and coated with asphalt cement, each having its own particular characteristics, which will be more suitable to specific design and construction purposes. before designing asphalt paving mixes, selection, proportioning and characterization of individual material are imperative to obtain the desired quality and properties of finished mix. for the current study, crushed aggregates were obtained from the local source (nibaee quarry) with maximum nominal size 12.5 mm, asphalt cement used with grade penetration (40-50) and portland cement as mineral filler. aggregates were sieved and recombined in the laboratory to obtain the selected gradation according to the sorb / r 9 as shown in figure 3. test methodes: various test methods and procedures have been developed and used by researchers over several decades to characterize the permanent deformation behavior of asphalt concrete. these test methods may in general be classified in to five types. • uniaxial stress testsunconfined cylindrical specimens in creep, repeated or cyclic loading. • triaxial stress testsconfined cylindrical specimens in creep, repeated or dynamic loading. • diametrical testscylindrical specimens in creep or repeated loading • shear stress tests -cylindrical specimens in shear creep or repeated loading • wheel track testsslab specimens or actual pavement cross sections. in this study uniaxial creep test is used uniaxial creep test: creep test mostly involves the application of static load over a specified period of time and measurement of the resulting strain. this is considered to be the simplest way to investigate the permanent deformation characteristics of bituminous mixtures and is the most widely used test method for determining material properties because of its simplicity and the fact that many laboratories have the necessary equipment and expertise. researchers conducted extensive studies using the unconfined creep test as the basis for predicting rut depth in asphalt concrete (van de loo, 1974). it was reported that the creep test must be performed at relatively low stress levels (within the linear range of the material) to obtain good comparisons between rut depths observed in test tracks and those calculated using creep test data. the need to use stress levels within the linear range has been attributed to the fact that the loading time in the field is small compared to the loading time in the creep tests. strain, measured as a function of the loading time at a fixed test temperature, is the usual output of the creep test. results of the creep test, when expressed as relative deformation (measured change in height divided by the original height), are found to be independent of the shape of the specimen and of the ratio of height to diameter, provided the specimen’s ends are parallel, flat and well lubricated. behavior of permanent deformation in asphalt concrete pavements under temperature variation 26 specimens, 2 in. (50.8 mm) in diameter and 4 in. (101.6 mm) in height are prepared in accordance with astm d1074. then they are left to cool at room temperature for 24 hrs. the test period consist of 1 hour of loading followed by 1 hour of unloading. results and discusstion a series of tests for marshall stability, flow and density –voids analysis are carried for selecting the optimum asphalt content for mixtures using 7 percent portland cement (by weight of total aggregate) as a filler and four different asphalt contents of (40-50) penetration grade from (4 to 6.4) percent (by weight of total mix) with an increment intervals of 0.8 percent, these specimens are prepared and tested for each mix variable. marshall properties at the selected optimum asphalt content (4.6) are shown below together with their corresponding test properties. bulk density ……………………………..2.338 air voids…………………………………4.24 % stability……………………………….11.8 kn. flow…………………………………….2.9 mm. stiffness……………..……..…….4.069kn/mm. in order to evaluate the permanent deformation on asphalt concrete mixture, uniaxial creep test is conducted at three stress levels (0.034, 0.069, 0.103) mpa. the typical test temperatures (10 °c, 20 °c, 40 °c, & 55 °c) are adopted in the laboratory for research study to accommodate the influence of temperature conditions, the accumulative strain results at the certain time are summarized in tables 1, 2, and 3 as shown below. all tables show that permanent strain increases with the increase in stress levels and temperature. the effect of temperature variation is significant as compared to stress levels. results of tables have been shown graphically in figures (4, 5, and 6). conclusion this summary research deals primarily with the ability of asphalt-aggregate mixtures to sustain imposed loads without permanent deformation. it considers the basic factors to minimize permanent deformation, laboratory tests for measuring mixture resistance to permanent deformation,. the following conclusions are based on the information presented herein.  rutting in pavements develops gradually with increasing wheel load applications and usually appears as a longitudinal depression in the wheel path with small shoulders to the sides. rutting is caused by a combination of densification (decrease in volume and, hence, increase in density) and shear deformation: however, shear deformation rather than densification is considered to be the primary cause of rutting in properly constructed pavements.  rutting can be reduced by using materials that better resist permanent deformation and/or by controlling loading conditions either by varying the pavement structure or the vehicular characteristics (e.g., tire pressures) to avoid the critical states of stress that intensify rutting.  temperature has a significant effect on rutting and, therefore, temperatures employed for design are relatively high to reproduce the most unfavorable pavement conditions.  at low temperature permanent strain increases by 55% with the increase in stress levels from low to highest value.  permanent strain increases by 79% at the degree of temperature is 40 °c with the increase in stress levels from low to highest value.  at degree of temperature is 55 °c the resistance of sample until 30 mints for loading time under effect of highest stress. references: al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 26 american association of state highway and transportation officials (aashto). 2002. “design of new and reconstructed flexible pavements” chapter 3, design guide. pretoria. asphalt institute, 1996. “superpave tm mix design” superpave series sp-2, lexington, kentucky, usa. asphalt institute, 2003. “mix design method for asphalt concrete and other hot-mix types,” manual series no. 02, six edition, kentucky, usa. brown, e.r., and cross, s.a. 1992. "a national study of rutting in hot mix asphalt pavements". ncat report 92-5, national centre for asphalt technology. carpenter, s. h., 1993. permanent deformation: field evaluation. transport research record1417 materials and construction, asphalt concrete mixtures. transportation research board, national academy press, washington eisenmann, j. and hilmar, a. (1987), influence of wheel load and inflation pressure rutting effect of asphalt pavements experiments and theoretical on the investigations, proceedings of the sixth international conference on structural design of asphalt pavements, vol. 1, ann arbor, michigan huber, g.a., and heiman, g.h. 1989. "effect of asphalt concrete parameters on rutting performance": a field investigation. pavement rutting seminarroads and transportation association of canada. huang, y.h., 1993. "pavement analysis and design", prentice hall, new jersey, united states of america. imran hafeez, 2009. "impact of hot mix asphalt properties on its permanent deformation behaviour" , 05uet/ phd-ce-22, university of engineering and technology, taxila. jorge b. sousa, joseph craus, 1991" summary report on permanent deformation in asphalt concrete" institute of transportation studies university of california, berkeley, california. kennedy, et al. roberts. 1996, hot mix asphalt materials, mixture design and procedure. napa research and education foundation, lanham, md. prithvi s.kandhal, 1998." hot mix asphalt for intersection in hot climates" , ncat report 98-06, national center for asphalt technology, auburn university. rabbira garba, 2002. "permanent deformation properties of asphalt concrete mixtures", thesis of phd, norwegian university of science and technology, ntnu. stumpf, w., van rooyen, g.t., 2007, mechanical metallurgy nmm 700, course notes, university of pretoria. sorb / r9 .general specification for roads and bridges, section r /9, ministry of housing and construction , republic of iraq,2004. van de loo, p.j. (1974), creep testing, a simple tool to judge asphalt mix stability, proceedings, the association of asphalt paving technologists, vol. 43. behavior of permanent deformation in asphalt concrete pavements under temperature variation 26 sieve no. surfacing course specification limits passing percentage % inch mm 3/4 19 100 100 1/2 12.50 90-100 95 3/8 9.50 76-90 83 no.4 4.75 44-74 59 no.8 2.36 28-58 43 no. 50 0.30 5-21 13 no. 200 0.075 4-10 7 table 1 mean accumulated strain *10^-3(mm/mm) (εp) of mixes at stress equal to 0.034 mpa time (min.) temperature, °c 10 20 40 55 0.10 0.2013 0.2282 0.5298 1.2519 0.25 0.2324 0.3449 0.6234 1.5828 0.50 0.3022 0.5012 0.9204 2.1149 1.00 0.4338 0.7898 1.0838 2.4021 2.00 0.5628 0.8619 1.2392 2.7132 4.00 0.6744 0.9737 1.5360 3.0873 8.00 0.7578 1.1086 1.8238 3.5573 15.00 0.9211 1.3507 2.2524 4.4918 30.00 1.0675 1.5763 2.3671 5.3422 45.00 1.1344 1.6558 2.4188 5.6225 60.00 1.1549 1.6849 2.4739 5.7534 unloading 0.10 0.8367 1.1955 1.8290 4.2248 0.25 0.8142 1.1763 1.7619 4.1868 0.50 0.8093 1.1612 1.7435 4.1552 1.00 0.8074 1.1542 1.7267 4.1398 2.00 0.8001 1.1398 1.7047 4.1077 4.00 0.7945 1.1348 1.6943 4.0859 8.00 0.7860 1.1239 1.6869 4.0576 15.00 0.7830 1.1196 1.6782 4.0376 30.00 0.7815 1.1165 1.6681 4.0142 45.00 0.7790 1.1130 1.6602 4.0007 60.00 0.7780 1.1109 1.6569 3.9914 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 67 table 2 mean accumulated strain *10^-3(mm/mm) (εp) of mixes at stress equal to 0.069 mpa time (min.) temperature, °c 10 20 40 55 0.10 0.2034 0.2552 1.7684 2.5922 0.25 0.2387 0.4648 1.9833 3.0154 0.50 0.3325 0.5882 2.5032 3.6854 1.00 0.5336 0.8098 3.1264 4.5866 2.00 0.7028 1.0602 3.6681 5.2532 4.00 0.8253 1.2385 3.9843 5.9441 8.00 0.9567 1.7752 4.4067 7.1188 15.00 1.0653 2.2280 4.9143 8.3165 30.00 1.2076 2.8950 6.3087 8.8348 45.00 1.3211 3.3154 6.9554 9.3241 60.00 1.4578 3.6114 7.5318 9.6328 unloading 0.10 1.2456 3.3941 6.1351 6.8478 0.25 1.2159 3.3579 5.9566 6.6324 0.50 1.2023 3.3300 5.9138 6.5379 1.00 1.1976 3.2961 5.8854 6.4922 2.00 1.1945 3.2731 5.8497 6.4475 4.00 1.1891 3.2411 5.8133 6.4164 8.00 1.1822 3.2256 5.7724 6.3811 15.00 1.1781 3.1655 5.7432 6.3567 30.00 1.1732 3.0834 5.7068 6.3305 45.00 1.1690 3.0103 5.6715 6.3211 60.00 1.1631 2.9956 5.6143 6.3145 behavior of permanent deformation in asphalt concrete pavements under temperature variation 67 table 3 mean accumulated strain *10^-3(mm/mm) (εp) of mixes at stress equal to 0.103 mpa time (min.) temperature, °c 10 20 40 55 0.10 0.5671 1.1895 2.4532 3.4521 0.25 0.7221 1.2933 2.9035 3. 8544 0.50 0.9074 1.4264 3.8567 4.6933 1.00 1.0351 1.9511 4.3611 5.3654 2.00 1.1691 2.2056 4.9033 7.6523 4.00 1.3270 2.7581 5.5632 9.1711 8.00 1.5253 3.1094 6.3854 11.0345 15.00 1.8037 4.0521 8.1385 12.8485 30.00 1.9752 4.7281 9.6351 14.3723 45.00 2.0844 5.1283 10.4365 60.00 2.1351 5.3655 10.7352 unloading 0.10 1.8293 3.7266 8.5214 0.25 1.7947 3.6436 8.2738 0.50 1.7710 3.6186 8.2145 1.00 1.7652 3.5910 8.1074 2.00 1.7541 3.5472 8.0257 4.00 1.7468 3.5138 7.9623 8.00 1.7421 3.4988 7.9285 15.00 1.7403 3.4772 7.8932 30.00 1.7390 3.4614 7.8815 45.00 1.7378 3.4524 7.8784 60.00 1.766 3.4578 7.8632 figure 1 accumulated plastic strains in pavements (after asphalt institute, 1996) al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 66 figure 2 typical repeated load permanent deformation behaviors of pavement materials (aashto design guide, 2002) figure 3 gradations of aggregate according to the sorb / r 9 asphalted surfacing course behavior of permanent deformation in asphalt concrete pavements under temperature variation 66 figure 4 influence of temperature on accumulated strain at stress equal to 0.034 mpa figure 5 influence of temperature on accumulated strain at stress equal to 0.069 mpa figure 6 influence of temperature on accumulated strain at stress equal to 0.103 mpa al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 455 relieve and remove radon-222 resulting the decay of the depleted uranium-238 from wells of babylon institute drilled by kerbala foundation of ground water company abstract radon gas is unstable, it releases energy by emitting alpha particles, and is soluble in water and is often found in the ground water. decays of radon emits alpha particles and beta particles. the energy released from these decay products results in damage to biological tissues which may lead to cancer. the health consequences of radon are well documented. measurements of natural radioactivity in soil and ground water have been studied. radionuclides present in soil include ra226 , th232 , and k40. gamma rays dose depends on the geological and geographical and appears in many levels in soils , the knowledge of gamma distribution in soils and well water play important role for protection against radiation. drilling company drills 4 wells in babylon institute. doses, statistical information's about these wells are studied, also contours between real and estimated values are drawn. testes are done in babylon environmental office الخالصة ان فى المياه الجوفية. وكذلك يتواجدفى الماء يذوبغير مستقر حيث يحرر الطاقة على شكل دقائق الفا وهو هو غاز غاز الرادون يعمل على تدمير بيولوجية االنسجة للكائن ةمنتج الطاقة المتحرران بيتا. كذلك دقائق الفا و انبعاث لىيؤدى ا انحالل غاز الرادون الى االصابة بمرض السرطان. ان العواقب الصحية الخطيرة للرادون موثقة توثيقا جيدا. لقد تم دراسة يؤدىالحى وبالتالى ان ). ra226 , th232 , and k4ية. النويدات المشعة الموجودة فى التربة هى (النشاط االشعاعى للرادون فى التربة والمياه الجوف تركيز اشعة كاما يعتمد على مجموعة من العوامل الجيولوجية والجغرافية وممكن ان يظهر هذا التركيز فى مستويات االعماق ر يساعد على الحماية من مخاطر هذا االشعاع. لقد تم المختلفة للتربة. ان النظام المعرفى لتوزيع اشعة كاما فى التربة ومياه االبا ابار من قبل شركة حفر متخصصة فى المعهد التقنى بابل. لقد تم دراسة تراكيز اشعة كاما والبيانات االحصائية لهذة االبار. 4حفر حليل فى دائرة بيئة بابل باشراف فريق بيئى لقد تم رسم مالمح هذة التراكيز والمقارنة بين القيم الحقيقية والمقدرة. لقد تم القياس والت متخصص. key words: wells, statistical values, radiation, dose, gamma ray 1. introduction uranium and other underground miners were subject to elevated cancer risks, due to exposure to high concentrations in air of the radioactive decay products of the natural radioactive gas radon. dr. abbas ali mahmood/ ph.d nuclear engineering /assistant professor/technical institute of babylon-hilla dr. eman mohammed abdullah/ ph.d accounting/assistant professor/technical institute of babylon-hilla al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 456 radon is a naturally occurring radioactive noble gas which exists in several isotopic forms [nero.1989]. only two of these isotopes occur in significant concentration in the general environment; radon-222 a member of the radioactive decay chain of uranium-238, and radon-220 is a member of the decay chain of thorium-232 .radon is the first and only gaseous and inert element of the radioactive chains, so that it can easily leave the place of production like ,soil, rock and building material which enter the indoor air. contribution is made by thoron (half life is 55 seconds) which is small when compared with the radon (half life is 3.82 days). the main source of indoor radon is its immediate parent radium-226 in the ground of the site and in the building materials [castrbn, winqist, and miikelainen, 1985]. in most situations it appears that elevated indoor radon levels originate from radon in the underlying rocks and soils. this radon may enter living spaces in dwellings by diffusion or pressure driven flow if suitable pathways between the soil and living spaces are present. it should be noted, however, that in a minority of cases elevated indoor radon levels may arise due to the use of building materials containing high levels of radium226. for those who live close to the ground, the radium concentration in soil usually lies in the range 10 bq/kg to 50 bq/kg, but it can reach values of hundreds bq/kg, with an estimated average of 40 bq/kg. typical radon concentrations in soil gas range from 10000 bq/m3 to 50000 bq/m3 [castrbn, 1993]. the potential for radon entry from the ground depends mainly on the activity level of radium-226 in the subsoil and its permeability with regard to air flow. the ground could also be contaminated with waste tailings from uranium or phosphate mining operations with enhanced activity levels. under pressure occurs in most houses if either the adjustment of inlet and outlet of air in forced ventilation systems or the outdoor air supply for vented combustion appliances is inappropriate. the under pressure may be considerable for all types of ventilation systems when the inlet air is restricted too much [castrbn and finnish1993]. in wells drilled in rock the radon concentration of the water may be high, when such water is used in the household, radon will be partially released into the indoor air, causing an increase in the average radon concentration. radon concentrations in tap-water from deep wells can range from 100 kbq/m3 to 100 mbq/m3. the indoor radon concentration in these regions may already be high due to high rates of radon entry from the ground. the world average radon concentration in all types of water supplies is assumed to be 10 kbq/m3. the main sources of indoor radon are; soil and water from deep wells. experimental work carried out and show that radon from soil represents generally the most important source of indoor radon [asikainen and kahlos 1980], [bruno1983], [damkjaer, and korsbech1985], and [nazaroff 1987]. the actions to reduce indoor radon concentration are mainly oriented to limit the ingress of radon from soil. when we use water radon is released into the air, we use a dishwasher, washing machine, or take a shower or bath the radon in the water raises the level of radon in the air. the two processes methods used to capture radon atoms are; aeration and gac tank processes. 2. experimental work radon is responsible for most of the mean public exposure to ionizing radiation [wang, setlow, berwick, polsky, marghoob, and kopf 2001 ] and[toxological 1990]. its concentration is variable according to location and it is often the single biggest contributor to the amount of background radiation an individual receives. radon gas from natural sources [a citizen’s2007] and [font2009 ] can accumulate in buildings, especially in confined areas such as basements. no one can avoid the exposure to radon even though this may potentially cause damage. breathing high concentrations of radon can cause lung cancer and could even be the second most frequent cause of lung cancer according to the united states environmental protection agency [a citizen’s2007]. there are such techniques used to measure dose. alpha guard technique is one of radon measurements. radon detector is based on a design optimized pulse ionization chamber. the signals are transmitted to an electronic network for further digital processing. radon monitor is a al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 457 compact portable measuring system and can be completed by further external sensors for pressure and temperature. the systematic design to less the radon dose from groundwater out of wells to supply people with clean and pure water with no radioactive particles is shown in figure 1. figs (27) show processes of drilling wells (1-4). 3. results and discussion 3.1 chemical testes for wells of babylon institute site results showed that wells 1, 3, and 4 had given the worst values for each chemical variables listed in (table 1), while we note through (figure 8) that well no2 has given acceptance values for all variables. these variables are associated to assess the validity of well water for drinking or other purposes. 3.2 testes of radon for soil and water wells of babylon institute site iraq's future will see the adoption of the majority of the population of iraq on groundwater for lack of water reaching the river, so we must maintained these waters from radioactive contamination and other pollutions like radon gas because the area in question are contaminated with depleted uranium-238. foundation is digging a four wells up to a depth of 10 m. conducting tests of soil has been done by using sensitive devices to gas where the screening process can take up to 45 minutes. after the end of each test data are stored and transferred to computer to analyze the results to compare them to get the perfect location to invest and continue work. there are different techniques for radon measurements, the liquid scintillation technique has been used to determine radon dose in groundwater. it is important that the reasons urged for this research is the proliferation of cancer diseases significantly in the areas of pollution that have been selected. a number of wells are drilled in these sites to make sure that the groundwater is valid for drinking and irrigation operations and free from radioactive contamination. wells are drilled to maximum depth of 10 m. from several tests, we see that the high dose is at the maximum depth as shown in (tables 2 to7) and (figures 9 to 14) , this means that the dose is proportional directly to the depth. we see that the humidity of air inside well is the most influential physical variable affected on the dose in the remote depths. we conclude that the dose is directly proportional to the humidity of air which increases the risk of this gas. this gas causes lung cancer which is the most common among the population, while the relationship between pressure inside well and depth, this relationship is reversible. technical institute site soil test results show that the critical time of maximum dose is at 15-19 minutes, while the less dose value is at 1-6 minutes. figures (15 to 20) show that the standard deviation of well no2 is high enough in case of soil or water testes, this mean that this well is ok to use, others show according to real values, we can see for soil test that the contour of (figures 21 and 22) show high error rate between real and estimated values of radon concentration in wells no 2 and 3. also ground water test contour show there is high rate errors in wells no2 and 3. this error causes as a result of variation of depleted uranium concentration at the moment. outdoor air usually acts as a diluting factor, due to its normally low radon concentration, but in some cases, as in high rise apartments built with materials having very low radium content, it can act as a real source. the radon concentration in outdoor air is mainly related to atmospheric pressure. alpha guard radon monitor was used as an important technique to measure radon concentration in ground water, temperature, pressure, and humidity of babylon institute wells . such short term measurements are commonly carried out to provide both cost and rapid results .it was found that the al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 458 radon concentration with maximum value, while temperature with low limits. the humidity measure values with high levels .each test need 35 minutes to collect data .the number of data taken during operation is 35 value for each variable studied. varying proportion. (figures 21 to 26) show the error in estimating radon concentration 4. conclusion radium, radon and uranium are grouped together because they are radionuclides, unstable elements that emit ionizing radiation. ionizing radiation can cause toxicity when the particles pass into or through the body at high speed. if a collision occurs with the molecules of living cells, they may be damaged. these particular radionuclides emit radioactivity primarily in the form of alpha particles. alpha radiation cannot pass through the dead outer layers of the skin. therefore, these substances are a health risk only if taken into the body by ingestion or inhalation. radium has been used as a source of radiation to treat certain cancers. radon gas can be found in the soil because of decay from the parent element uranium. radon can also migrate from soil into groundwater, which can become another route of exposure if the groundwater is used as a water supply source. radionuclides are undetectable by the human senses, so only analytical testing can determine if they are present in water. because they are associated with rock, wells drilled into bedrock are more likely to contain elevated levels of radionuclides than shallow or dug wells. references [1] nero, a.v. jr., earth, air, radon and home, physics today, april, (1989). [2] castrbn, o., voutilainen, a., winqist, k. and miikelainen, i., studies of high indoor radon areas in finland, sci. total. environ, (1985). [3] castrbn, 0., radon reduction potential of finnish dwellings, proceedings of the first international workshop on indoor radon remedial action, rimini, italy, 27th june 2th july 1993 (in press on radiat. prot. dosim.), (1993). [4] castrbn, 0., finnish centre for radiation and nuclear safety, helsinki, personal communication, ( 1993). [5] asikainen, m. and kahlos, h., natural radioactivity of drinking waters in finland, health phys. (1980). [6] bruno, r.c., sources of indoor radon in houses, a review, j. air poll. contr. assoc, (1983). [7] damkjaer, a. and korsbech, u., measurement of the emanation of radon-222 from danish soils, sci. total environ, (1985). [8] nazaroff et al, experiments on pollutant transport from soil into residential basements by pressure driven air flow, environ. sci. technol., (1987). [9] wang s, setlow r, berwick m, polsky d, marghoob a, kopf a, bart r ,ultraviolet and melanoma: a review, j am acad dermatol 44 (5): 837–46, (2001). al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 459 [10] toxological profile for radon, agency for toxic substances and disease registry, u.s. public health service, in collaboration with u.s. environmental protection agency, december, (1990). [11] a citizen’s guide to radon, u.s. environmental protection agency,( 2007). [12] c.papaste fanon, measurement radon in soil and ground waters: a review 50, (2007). [13] font, li, on radon surveys: design and data interpretation, 67 (968-964), (2009). well no ph e.c t.d.s no3 po4 so4 1 6.4 29530 23624 1.37 0.24 7700 2 6.7 20670 15502. 5 1.58 0.22 5700 3 7.02 28500 22515 2.03 0.25 7350 4 6.8 28800 22752 1.46 0.20 7150 time (min) rn222(kb/ m3) rn222+error in bq(bq/m3) tempera ture (co) air pressure (mbar) humidit y % 1 0.00013 30.00 18.8 1018 29.6 2 0.00013 3.00 18.4 1018 29.9 3 0.02638 41.00 18.5 1018 29.1 4 0.00013 3.00 19.1 1018 29.6 5 0.02350 35.00 19.6 1018 29.8 6 0.02238 40.00 19.5 1018 29.1 7 0.11100 105.50 19.8 1018 29.0 8 0.21600 163.00 20.4 1018 28.0 9 0.34800 208.00 20.3 1018 28.6 10 0.05325 71.50 19.6 1018 27.4 11 0.29400 194.00 19.4 1018 28.0 12 0.24100 197.00 20.3 1018 29.1 13 0.37800 222.00 20.8 1018 28.0 14 0.50800 258.00 20.6 1018 27.5 15 0.52800 244.00 20.6 1018 27.0 16 0.58400 280.00 20.6 1018 26.9 17 0.86000 340.00 20.9 1018 27.0 18 1.08800 388.00 21.6 1018 26.9 19 0.91600 360.00 21.6 1018 26.4 20 0.89600 360.00 22.0 1018 28.0 21 0.63600 310.00 21.8 1018 26.4 table. 1: chemical results of wells no (1-4) for babylon institute site-hilla t al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 460 time (min) rn222(kb /m3) rn222+err or in bq(bq/m3) temper ature (co) air pressure (mbar) hum idity % 1 176.00 133.00 20.8 1018 24.8 2 7.06 180.00 21.4 1018 25.9 3 95.50 193.00 21.6 1018 24.8 4 134.00 222.00 21.3 1018 25.3 5 5.81 163.00 21.1 1018 24.8 6 2.19 71.00 21.6 1018 24.1 7 1.02 40.75 21.9 1018 24.1 8 120.50 208.00 22.0 1018 24.1 9 3.42 105.00 21.9 1018 24.1 10 5.84 163.00 21.6 1018 24.3 11 2.22 71.50 22.1 1018 24.1 12 62.25 169.00 22.6 1018 23.8 13 3.45 105.50 22.8 1018 23.6 14 49.50 179.00 22.4 1018 23.6 15 233.00 234.00 22.0 1018 23.1 16 42.00 179.00 21.9 1018 23.1 17 2.22 71.50 22.1 1018 23.3 18 7.03 163.00 22.6 1018 23.8 19 6.56 163.00 22.9 1017 23.6 20 4.66 142.00 22.9 1017 23.6 21 3.42 105.00 22.9 1017 23.1 table. 3: soil test of well no. 2 for babylon institute site al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 461 time (min) rn222(kb /m3) rn222+err or in bq(bq/m3) temper ature (co) air pressure (mbar) humi dity % 1 0.01663 0.08100 21.1 1017 24.1 2 0.00227 0.07150 21.5 1017 24.1 3 27.39200 3.79200 22.0 1017 23.1 4 57.08800 2.73600 22.1 1017 23.3 5 60.41600 1.90400 22.1 1017 23.0 6 56.32000 1.81600 21.8 1017 22.5 7 49.40800 2.68800 21.5 1017 22.6 8 53.76000 1.81600 21.6 1017 23.1 9 55.29600 1.53600 21.8 1017 23.1 10 59.13600 2.04800 21.6 1017 23.1 11 63.48800 2.17600 21.5 1017 23.1 12 48.64000 2.49600 21.5 1017 22.4 13 33.79200 3.52000 21.4 1017 22.0 14 16.76800 3.48800 21.4 1017 22.0 15 7.55200 3.00800 21.3 1017 22.5 16 3.74400 2.27200 21.3 1017 22.0 17 2.32000 1.96800 21.1 1017 22.5 18 3.28000 1.86400 21.5 1017 22.0 19 3.24800 1.90400 21.9 1017 21.8 20 1.93600 1.36000 22.4 1017 21.6 21 5.18400 1.93600 22.5 1017 21.4 table. 4: soil test of well no. for babylon institute site al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 462 tim e (min) rn222(kb /m3) rn222+err or in bq(bq/m3) temper ature (co) air pressure (mbar) hum idity % 1 9.50 30.00 17.3 1020 27.5 2 10.55 42.25 17.4 1020 28.0 3 262.00 208.00 17.5 1020 26.9 4 17.00 71.50 17.5 1020 26.9 5 9.50 41.00 17.5 1020 26.5 6 16.75 60.25 17.5 1020 26.9 7 42.00 105.50 17.5 1020 26.9 8 10.25 41.00 17.5 1020 26.9 9 21.50 72.00 17.5 1020 26.9 10 22.00 72.00 17.6 1020 26.9 11 80.50 142.00 17.6 1020 26.9 12 44.25 105.50 17.6 1020 26.9 13 124.50 163.00 17.6 1020 26.9 14 42.50 105.50 17.6 1020 26.5 15 167.00 179.00 17.8 1020 26.4 table. 5: water test of well no. 1 for babylon institute site al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 463 16 181.00 170.00 17.8 1020 26.4 17 38.50 105.50 17.8 1020 26.9 18 39.25 105.00 17.8 1020 26.9 19 258.00 208.00 17.9 1020 26.9 20 16.75 71.00 17.9 1020 26.9 21 350.00 234.00 17.9 1020 27.5 tim e (min) rn222(kb /m3) rn222+err or in bq(bq/m3) temper ature (co) air pressure (mbar) hum idity % al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 464 1 0.07050 0.41800 23.5 1017 17.6 2 0.08750 0.77600 23.5 1017 17.6 3 22.40000 3.45600 23.6 1017 17.6 4 37.63200 3.58400 23.6 1017 17.6 5 43.77600 3.15200 23.4 1017 18.1 6 42.24000 3.28000 22.9 1017 18.1 7 37.37600 3.24800 23.3 1017 18.6 8 41.72800 3.26400 23.8 1017 18.9 9 46.33600 2.43200 24.0 1017 19.3 10 37.12000 3.58400 23.9 1017 19.8 11 37.12000 3.29600 23.9 1017 19.3 12 38.65600 3.08800 24.1 1017 18.6 13 22.78400 3.53600 24.8 1017 18.6 14 13..05600 3.04000 25.1 1017 18.6 15 7.90400 2.84800 25.4 1017 18.1 16 7.77600 2.89600 25.3 1016 17.6 17 3.76000 2.41600 25.0 1016 17.6 18 4.16000 2.33600 24.8 1016 17.0 19 4.04800 2.09600 25.5 1016 17.6 20 5.08800 2.19200 25.5 1016 17.6 21 4.51200 2.22400 26.0 1016 17.0 table. 6: water test of well no. 2 for babylon institute site table. 7: water test of well no. 3 for babylon institute site al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 465 tim e (min) rn222(kb /m3) rn222+err or in bq(bq/m3) temper ature (co) air pressure (mbar) humid ity % 1 38.75 66.00 19.6 1019 28.5 2 10.00 41.25 19.6 1019 28.5 3 21.38 72.00 19.8 1019 28.0 4 45.25 105.50 19.6 1019 28.5 5 80.00 142.00 19.6 1019 28.5 6 37.50 88.00 19.6 1019 28.6 7 11.00 41.00 19.6 1019 28.5 8 0.13 3.00 19.8 1019 28.1 9 51.25 105.50 19.6 1019 28.3 10 25.63 72.00 19.8 1019 28.6 11 0.13 3.00 19.6 1019 28.6 12 27.88 72.00 19.8 1019 28.0 13 13.13 41.00 19.8 1019 28.0 14 29.00 72.00 19.8 1019 28.0 15 48.25 88.00 19.8 1019 28.0 16 0.13 3.00 19.8 1019 28.0 17 30.38 72.00 19.8 1019 28.0 18 143.00 163.00 19.8 1019 28.0 19 28.63 72.00 19.8 1019 27.5 20 12.94 40.50 19.8 1019 27.5 21 13.94 41.00 19.9 1019 28.0 t motor to draw water fund graphite air compresso fan to pull moist air al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 466 figure. 3 soil and ground water radon test for well no 2. figure. 2 soil and ground water radon test for well no 1. figure. 1 systematic design to less radon dose al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 467 figure. 5 soil and ground water radon test for well no 4. figure. 4 soil and ground water radon test for well no 3. figure. 6 space photo of netherland and foundation of ground water companies figure. 7 soil and ground water radon test for 80 street-almarashedah babylon institute engraved by company of drilling wellsfoundation of ground waterkerbala city-(10m) 80 street – almarashedah by netherland company – (35m) al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 468 figure. 9 plot of well soil no1 figure. 10 plot of well soil no2 al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 469 figure. 11 plot of well soil no3 figure. 12 plot of well water al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 470 figure. 15 probability plot for well soil no1 al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 471 figure. 17 probability plot for well soil no3 figure. 18 probability plot for well water no1 al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 472 figure. 19 probability plot for well water no2 figure. 20 probability plot for well water no3 figure. 22 soil well no 2 contour plot figure. 21 soil well no 1 contour plot al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 473 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 952 use drainage water f0r agricultural purposes asst. prof. kadhim naief al-ta’ee asst. lect. hana m. alkassar (college of engineering, babylon university) (najaf technical institute) altaee_ kadhim@yahoo.com hana_alkassar@yahoo.com lect. ameera naji hussein (najaf technical institute) marl10@ yahoo.com received 14 september 2014 accepted 20 january 2015 abstract in this study the samples of southern drainage water and euphrates river water were taken from the north region of almanadhra city [najaf province-iraq].those samples were mixed with different ratios by adding drainage water to river water to get a new solution containing different salt. to find a standard indicator of water quality that sodium adsorption ratio (sar) as well as examine electrical conductivity (e.c.).the results were (3.15, 3.9, 4.2, 4.8, 5, 5.2, 5.3, 5.4, 5.5, 5.6, 5.8) for (sar), (1.58, 2.3, 3.06, 3.75, 4.35, 5.11, 5.85, 6.33, 7.2, 7.63, 8.2) for (e.c.) respectively. then, examine those samples of salt water where used as an irrigation water supplied to several types from of oryza satival seeds (al-forat class, yassmin class, amber baraka class) to test germination of seeds. the results of germination of seeds with those samples of irrigation water at mixing drainage water ratios (0-100)% equal to (100-5)% for al-forat class, (90-0)% for yassmin and amber baraka class respectively. key words: saline waters, irrigation and drainage water, sea water زراعيةال لإلغراضاستخدام ماء البزل م. أميرة ناجي حسين أ.م. كاظم نايف الطائي م.م. هنـــاء محمود الكســار نجف /المعهد التقني نجف /جامعة بابل المعهد التقني/كلية الهندسة الخالصة . ]العراق-محافظة النجف[الفرات من منطقة شمال مدينة المناذرةنهر ماء البزل الجنوبي و ماء عينات من أخذت, دراسةفي هذا ال يحتوي على ملح مختلف. لنهر للحصول على محلول جديدبواسطة إضافة ماء البزل إلى ماء ا بنسب مختلفةتلك العينات خلطت (. وكانت .e.cإلى فحص التوصيلة الكهربائية ) إضافة sar)نسبة إمتزاز الصوديوم ) تلكإليجاد المعيار القياسي لنوعية المياه , 34 ,4.5 ,.055 ,5..3 ,2.53.., ) (sar( بالنسبة )3.4, 3.5, 3.3, 3.2, 3.5, 3.4, 3, 2.4 ,2.4, 5.3, 3..5)النتائج كماء حيث استخدمت المالح الماء من عيناتتلك الاختبار ثم ( على التوالي..e.c( بالنسبة )4.4, 55.., 4.., 5.55, 3.43, ...3 نتائج أنبات . حص انبات البذورلف (, صنف الياسمين, صنف عنبر البركةعدة أصناف من بذور الرز)صنف الفراتجهز لري (% لصنف 0-30(% لصنف الفرات , )3-00.(% تساوي ) 00.-0ماء بزل )خلط ات ماء الري عند نسب البذور مع تلك عين الياسمين وعنبر البركة على التوالي. mailto:kadhim@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 962 1introduction different crops require different irrigation water qualities. therefore, testing the irrigation water prior to selecting the site and the crops to be grown is critical. the quality of some water sources may change significantly with time or during certain periods (such as in dry/rainy seasons), so it is recommended to have more than one sample taken, in different time periods. the chemical properties of the irrigation water are discussed. which it refer to the content of salts in the water as well as to parameters derived from the composition of salts in the water; parameters such as ec,tds (electrical conductivity, total dissolved solids), sar (sodium adsorption ratio). substituted colorado river water (900 mg/l total dissolved salts) after seedling establishment by percentages of alamo river (drainage water of 3500 mg/l total dissolved salts). in the test were 76 in wheat, 82 in sugar beets, and 54 in cotton.[rhoades,(1984)]. results show that ratio 1:1 mixture of caspian sea and well water can be used for irrigation without a significant reduction in barley yield, provided this is applied at ear formation. however, when applied at stem elongation, significant yield reduction occurs. soil analysis after harvest showed that the ec had increased significantly, especially with irrigation applied at stem elongation. [ dordipour et al, (2004)]. water drainage was tested and used agricultural purposes were used samples of water drainage and mixed with samples of river water at different ratios to get a new solution containing different salt proportions(drainage and river from region dujaili/ wasit governorate). tested (ca, na, mg) to find a standard indicator of water quality, labeled sodium adsorption ratio (sar) as well as (ec, ph). and compare the results with the salinity laboratory system u.s. (ussl) and food agriculture organization of the united nations (fao). found the proportions of mix ratios (10%drainage + 90%river), (20%drainage + 80%river) are the ratios preferred and more e.c. increased salt concentration in the water and the ph values of this water was within normal limits.[al-humairi,(2013)]. 2characterizing salinity there are two common water quality assessments that characterize the salinity of irrigation water. the salinity of irrigation water is sometimes reported as the total salt concentration or total dissolved solids (tds). the units of tds are usually expressed in milligrams of salt per liter (mg/l) of water. this term is still used by commercial analytical laboratories and represents the total number of milligrams of salt that would remain after 1 liter of water is evaporated to dryness. tds is also often reported as parts per million (ppm) and is the same numerically as mg/l. the higher the tds, the higher the salinity of the water the other measurement that is documented in water quality reports from commercial labs is specific conductance, also called electrical conductivity (ec). ec is a much more useful measurement than tds because it can be made instantaneously and easily by irrigators or farm managers in the field. salts that are dissolved in water conduct electricity, and, therefore, the salt content in the water is directly related to the ec. the ec can be reported based on the irrigation water source (ecw) or on the saturated soil extract (ece). units of ec reported by labs are usually in millimhos per centimeter (mmhos/cm) or decisiemens per meter (ds/m). one mmho/cm=1 ds/m. ec is also reported in micrommhos per centimeter(µmhos/cm), (1µmhos=1/1000). [stephen r. grattan,(2002)] . 3classification of saline waters for the purpose of identifying the levels of water salinities for which these guidelines are intended, it is useful to give a classification scheme. such a classification is given in table (1) in terms of total salt concentration.[rhoades, et.al,(1992)] al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 962 4sodium hazard reductions in water infiltration can occur when irrigation water contains high sodium relative to the calcium and magnesium contents. this condition, termed “sodicity,” results from excessive soil accumulation of sodium. sodic water is not the same as saline water. sodicity causes swelling and dispersion of soil clays, surface crusting and pore plugging. this degraded soil structure condition in turn obstructs infiltration and may increase runoff. sodicity causes a decrease in the downward movement of water into and through the soil, and actively growing plants roots may not get adequate water, despite pooling of water on the soil surface after irrigation. the most common measure to assess sodicity in water and soil is called the sodium adsorption ratio (sar). sodium adsorption ratio (sar): is a measure of the suitability of water for use in agricultural irrigation, as determined by the concentrations of solids dissolved in the water. it is also a measure of the sodicity of soil, the sar defines sodicity in terms of the relative concentration of sodium (na) compared to the sum of calcium (ca) and magnesium (mg) ions in a sample, the sar assesses the potential for infiltration problems due to a sodium imbalance in irrigation water. the sar is mathematically written below by equation (1), where na, ca and mg are the concentrations of these ions in milliequivalents per liter (meq/l). concentrations of these ions in water samples are typically provided in milligrams per liter (mg/l). to convert na, ca, and mg from mg/l to meq/l, you should divide the concentration by 22.9, 20, and 12.15 respectively. [bauder.et.al (2012)] (1) 5experimental work in this study the samples of southern drainage water and euphrates river water were taken from the north region of almanadhra city [najaf province-iraq].those samples were mixed with different ratios by adding drainage water to river water to get a new solution containing different salt proportions. the mix ratios were 90% of river water to 10% of drainage water, 80% to 20% and so on until 10% to 90% by 10% decrements and increments pure river water and pure drainage water, table (2) show the results of the tests done on these mix ratios starting with pure river water (without addition of drainage water) and ended at 100% drainage water (without river water). the mixing process was achieved in an enclosed containers and the tests were done in soil lab of kufa technical institute. a flame photometer (cl738, british origin) and e.c. meter ( usa origin) devices were used as an instruments to make the tests. the analysis of the mix composition was done to find out ions (na, ca, mg). the calcium and magnesium were estimated using correction method while sodium ion was reached by flame photometer. the electrical conductivity (e.c.) was estimated and then the value of sodium adsorption ratio (sar) was calculated using eq.(1). the mix water ratios of samples governed from lab were used as an irrigation water supplied to several types of rice (oryza satival) seeds which was brough from (abaa center of rice researches) in mushhab city (al-forat class, yassmin class and amber baraka class) to test the viability of seeds. the vitality of seeds was tested by taking (100) seed of all varieties of rice, varieties used in the work had been soaked in water for 24 hours to ensure moisten the seeds. the seeds were placed in plastic sterile dishes under warn laboratory conditions of temperature of 26º ± 1. the irrigation with water was provided regularly to maintain the necessary moisture for seed germination for seven days. the percentage of germination was (90%) of the amber 33 class, (100%) for the rest of the items by using eq. (2). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 969 percentage of germination = (2) 5.1applied study for different levels of salinity on seeds germination rice varieties the effect of different levels of salinity on seed germination was test by taking samples of each type of rice varieties used in the work and soaked in water for 24 hours to ensure moisten of the seeds. each (50) seeds were kept in plastic sterile dishes at a rate of three replicates and kept at temperature of 26º ± 1 with regular irrigation to those samples of salt water concentrations under watching by providing the necessary moisture for seeds germination for seven days. the percentage of germination was calculated from equation(2).table(3) show the results of the percentage of germination of the samples. the percentage of germination for seeds rice varieties are explained in figures. (1, 2, 3) taken. 6analysis of experimental results the results of the study applied to varieties of seed rice for those samples of salt water governed show a good percentage of germination of these seeds of different varieties of rice (al-forat class, yassmin class and amber baraka class ). as salinity of water increased the percentage of germination was decreased as shown in table (3) where pure water gives 100% germination for alforat class and 90% for yassmin class and amber baraka class. the10% increment of salinity shows a drop in germination of yassmin class and amber baraka class. the surprise results faced is that when 100% drainage water used, the germination is yassmin class was 0% while it was 5% for al-forat class. so saline water can be used safely for irrigation purposes, especially when it is used to plants which need more water for irrigation. the current results were ensured by the comparison with an international standards [rhoades, et.al] when the results are within the ratios given in this standard. 7conclusions 1. the salinity of water drainage that e.c (8.212) ds/m within the range (2-10) ds/m salinity as moderate condition, it can be used for irrigation for so many other plants if they are under adequate conditions and good management. 2. the ratios (90% of the river water +10% of the drainage water), (80% of the river water +20% of the water drainage) until (30% river water+70% of the drainage water), can be applied to different types of other plants successfully. 3. it is possible to get the high germination if the irrigation was controlled by alternative method in which the plants can be irrigated once by pure water and second time by drainage water . 4. alternative method mentioned in point 3 can be replaced by low-cost drip irrigation with saline water especially ratio (10% river water+90% of the drainage water). refernces [1] al-humairi, b.a. (2013)" treatment water drainage for agriculture" publisher: global journals inc. (usa), vol. 13 issue 6 version, online issn: 2249-4596. [2] dordipour, i. (2004). ameliorative role of k and zn on barley (hordeum vulgare l.) growth and yield under irrigation with caspian sea water. phd thesis . dept. of soil science. february 2004. tarbiat modarres university, iran (in persian). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 962 [3] rhoades j.d., 1984."using saline waters for irrigation". proc. lnt7 workshop on salt-affected soils of latin america. maracay, venezuela, oct. 23-30,1983p,p . 22-52. also published in scientific review on arid zone, vol. 2 :233-264. [4] rhoades, j.d., kandiah, a. and mashali, a.m. (1992). "the use of saline waters for crop production". fao irrigation and drainage paper 48. food and agriculture organization of the united nations, rome, 1992. [5] stephen r. grattan (2002) "irrigation water salinity and crop production" oakland: university of california division of agriculture and natural resources publication 8066. [6] t.a. bauder, r.m. waskom, p.l. sutherland and j. g. davis * (5/11) (2012)"irrigation water quality criteria" no. 0.506. table (1): classification of saline waters.[rhoades, et.al,(1992)] water class electrical conductivity ds/m salt concentration mg/l type of water non-saline <0.7 <500 drinking and irrigation water slightly saline 0.7 2 500-1500 irrigation water moderately saline 2 10 1500-7000 primary drainage water and groundwater highly saline 10-25 7000-15 000 secondary drainage water and groundwater very highly saline 25 45 15000-35 000 very saline groundwater brine >45 >45 000 seawater al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 962 table (2): drainage water & river water mix ratios, electrical conductivity and sodium adsorption ratio table (3): percentage of germination for seven days (sar) (e.c. ) (mmoh/cm) na (meq/l) mg (meq/l) ca (meq/l) mixing ratios (%) no. 3.15 1.58 6.6 1.6 7.2 100 river water 1 3.9 2.3 11 5 11 90 river +10drainage 2 4.2 3.06 14.4 13.5 10.6 20 drainage+80 river 3 4.8 3.75 17 8.8 16.4 30 drainage+70 river 4 5 4.355 19.3 12 18 40 drainage+60 river 5 5.2 5.112 21.4 14 20 50 drainage+50 river 6 5.3 5.85 22.6 14.8 22 60 drainage+40 river 7 5.4 6.33 23.5 10 28 70 drainage+30 river 8 5.5 7.2 26.3 16 30 80 drainage+20 river 9 5.6 7.63 28.4 18.1 33 90 drainage+10 river 10 5.8 8.212 31 21 35 100 drainage water 11 amber baraka class yassmin class al-forat class electrical conductivity e.c. mixing ratios (%) no. %90 %90 %100 1.579 100 river water 1 %80 %90 %100 2.283 90 river+10drainage 2 %60 %80 %90 3.06 20 drainage+80 river 3 %50 %70 %90 3.749 30 drainage+70 river 4 %40 %50 %70 4.355 40 drainage+60 river 5 %40 %50 %60 5.112 50 drainage+50 river 6 %35 %40 %60 5.846 60 drainage+40 river 7 %20 %30 %30 6.329 70 drainage+30 river 8 %10 %10 %25 7.19 80 drainage+20 river 9 %5 %5 %20 7.63 90 drainage+10 river 10 0 0 %5 8.212 100 drainage water 11 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 965 figure (1): percentage of germination for al-forat class for seven days al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 966 figure (2): percentage of germination for yassmin class for seven days figure (3): percentage of germination for amber baraka class for seven days al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 34 corrosion resistance of tempered heat treated carbon steel ck45 in sea water at different velocities huda mohammed abdul-aziz laith yousif yakoub abdullh kawaf jaber institute of technology institute of technology al_dywaniya technical institute baghdad baghdad dywaniya abstract the effect of tempering heat treatment on corrosion resistance of carbon steel din ck45 is investigated. test specimens (1.5*1.5*0.3) cm were prepared according to astm g71-30 tempering heat treatments at 150, 350 ◦ c were performed by heating the specimens in electrical furnace to 850 ◦ c and cooling in water then preheated to 150, 350 ◦ c and cooled in air. corrosion tests were investigated by electrochemical potential state cell in prepared salt water (sea water) at multi velocities (1, 2, and 3) m/min where the test specimen represents the positive electrode (anode) pole. tafel equation was adopted to calculate the corrosion rate. the obtained results show that the heat treatment improves the corrosion resistance by increasing the combination of iron with carbon reducing by that the combination of iron with oxygen which produces rust. on the other hand the increasing of velocity of the media (sea water) contributed in decreasing the corrosion rate because of reducing the assembling of ions on cathode pole. keyword: heat treatment, carbon steel, ck45, corrosion resistance. sea-water velocity. din ck45دراسة تأثير المعامالت الحرارة على مقاومة التاكل لفوالذ كاربوني وبتعريض ماء البحر الى سرع مختلفة . هدى محمد عبد العزيز ليث يوسف يعقوب عبد هللا خواف جبر مدرس مساعد س مساعد مدرس مساعد مدر ةتقني / الديوانيمعهد معهد تكنولوجي / بغداد معهد تكنولوجي / بغداد الخالصة تم اذ din ck45على مقاومة التاكل لفوالذ كربوني (تقسية، مراجعة)اثير المعامالت الحرارية تتم دراسة عاملة ماجريت .astm g 71-30 ةسم وفق مواصف (3 .0*1.5*1.5) تصنيع عينات اختبار التاكل بابعاد م تم اعادة التسخين ث لماءاوالتبريد ب ◦م 805الى درجة حرارة في فرن كهربائي حرارية تضمنت تسخين المعدن مثبت الجهد اختبار التآكل بواسطة جهاز إجراءتم .ءهواثم التبريد بال ◦م ) 005,005الى درجة حرارة ) مثلت العينات القطب الموجب آذ متر / الدقيقة (3,2,1)ذو سرع وباستخدام المحلول الملحي ) ماء البحر ( تبين ان اومن النتائج التي تم الحصول عليه. لالستقطاب وتم حساب معدل التآكل باستخدام معادلة تافل المعاملة الحرارية ساهمت في تحسين مقاومة التاكل من خالل زيادة اتحاد الكاربون مع الحديد والذي سيقلل من corrosion resistance of tempered heat treated carbon steel ck45 in sea water at different velocities 33 زيادة يساهم في (ماء البحر)ومن جهة اخرى فان زيادة سرعة الوسط .يولد الصدا ساالوكسجين الذي ب هاتحاد .تجمع ايونات الحديد على قطب الكاثودتقليل ة التآكل بسبب مقاوم introduction corrosion of metal is a major problem in construction company .oil and ship building and other engineering firms, where medium carbon steel is particularly used. corrosion can be defined as the destruction of a metal by chemical or electrochemical reaction with its environment. in cooling systems, corrosion causes two basic problems. the first and most obvious is the failure of equipment with the resultant cost of replacement and plant downtime. the second is decreased plant efficiency due to loss of heat transfer. corrosion occurs at the anode, where metal dissolves. often, this is separated by a physical distance from the cathode, where a reduction reaction takes place. an electrical potential difference exists between these sites, and current flows through the solution from the anode to the cathode. this is accompanied by the flow of electrons from the anode to the cathode through the metal. temperature is one of the critical environmental parameters in corrosion studies because of its severe effects on physicochemical and electrochemical reaction rates. for that corrosion resistance of steels is strongly connected to their microstructure obtained after heat treatments that are generally performed in order to achieve good mechanical properties. for that reason, there is currently a strong interest in the effect of the heat treatment on the corrosion resistance which is affected by the changes in the microstructure [1] [2].many studies investigated the effect of heat treatment on the microstructure and mechanical properties, m.b.ndaliman [8] study this under two different quenching medias (water and palm oil) achieving that best proprieties in strength and hardness in water is better than palm oil. adnan calic [3] shows that in different cooling rate we can obtain different microstructure and improved it by varying the cooling rate .thus; heat treatment is used to obtain desired proprieties of such as improving the toughness, ductility or removing the residual stresses, etc. he compared this study with literature survey as, bangaru and sachdev, [5] show that oil quenching produce ferrite-martensits phases and thin film of retained austenite. by slow air cooling the results in a large amount in retained austenite in addition to the ferrite and martensite. on the other hand with the applied cooling rate increasing the transformed structure evolve s from granular bainite, lower bainite, self tempred martensite, to finally martensite without self-tempering qiao etal [9] .among them, self-tempered martensite obtained in the transformed specimens cooled with rates of 25-80 c/min, exhibits the highest hardness values due to the precipitation of fine carbides. w. r. osório [10] investigate the effects of four different and conventional heat treatments (i.e., hot rolling, normalizing, annealing, and intercritical annealing) on the resulting microstructural patterns and on the electrochemical corrosion behavior of low carbon steel, it was found that the normalizing and the annealing heat treatments have provided the highest and the lowest corrosion resistances, respectively. and this is due to the residual stress from the martensite formation. on the other hand corrosion behavior of metals in sea water is affected by many environmental factors such as water temperature, dissolved oxygen content and velocity the effect of water velocity on metals corrosion behavior has got a great interest by researchers, kamilia gruskevica [7] study the effect of water velocity on corrosion resistance of steel pipes finding that the corrosion resistance decreased in low or medium flow media by a percentage between 20-50% than rapid flow. the aim of this paper is to examine the effect of phases which obtained by heat treatment of medium carbon steel ck 45 at different velocities on corrosion resistance al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 34 experimental work metal selection: medium carbon steel ck45 according to din specification were chosen because of its wide range of engineering applications such as shafts, molds, connecting rods and its chemical analysis indicated in table 1 which was conducted by arl spectrometer. fabrication of specimens: test specimens for corrosion test were fabricated as (1.5*1.5*3) cm according to the astm g 71-30. categorization of test specimens: after the manufacturing of the test specimens were categorized into groups as shown in the table 2. heat treatment: the heat treatments were performed on the specimens shown in table 2. the process consist of heating the specimens of symbols (b, c) to 850°c for 0.5 hour and water cooling., then samples ( b) and ( c) were preheated to 350 °c for ( b) and 150°c for ( c) then cooled in air respectively. tests and examination: microstructure test: test of microstructure on specimens groups in table 2, the specimens were prepared as follows: the specimens are treated with emery paper of grades 120,350,500,800. they were polished with cloth and alumina al2o3 solution. aqueous treatment using nital solution composed of 2% nitric acid and 98% metheyl alcohol. optical examination of samples was performed using optical microscope equipped with camera and connected to a computer. the microstructure is shown in figure1. electrochemical tests the prepared specimen is fixed with in the holder the reference electrode was fixed about (1 mm) apart from the surface of the specimen to be tested. the reference electrode used in this study was saturated calomel electrode (sce). the auxiliary electrode used in the electrochemical was platinum type. the specimen holder (working electrode) , together with the reference and auxiliary electrode were inserted in their respective position in the electrochemical cell used for this purpose than can fit all these electrodes as shown in figure 2 constant potentials (anodic or cathodic) can be imposed on the specimen, by using the potentiostat (mlab200 of bank eleck. germany). this potentiostat is able to induce a constant potentials ranging from (-1 + lv) the potentials of the standard reference electrode used in this study (sce). the potential difference between the working and reference electrode (we – re) and any current passing in the circuit of working electrode were auxiliary electrode can be measured by using the sci computer software. any potential difference between the working and reference electrodes circuit can be automatically recorded. the result and plots were recorded using window xp. the scan rate can be selected also. polarized resistance tests were used to obtain the micro cell corrosion rates. in the tests, cell current reading was taken during a short, slow sweep of the potential. the sweep was taken from (-100 to +100) mv relative to (opc). scan rate defines the speed of potential sweep in mv/sec. in this range the current density versus voltage curve is almost nearly linear. a linear data fitting of the standard model gives an estimate of the polarization resistance, which used to calculate the corrosion current density (lcorr) and corrosion rate. the tests were performed by using a wenking mlab multi channels and sci mlab corrosion measuring system from bank electronics – intelligent controls gmbh, germany 2007, as shown in figure 2. the result of electrochemical corrosions shown in table 3 by using [4] corrosion resistance of tempered heat treated carbon steel ck45 in sea water at different velocities 34 tafel eq. (c.r=0.13*lcor* eq. wt/d) (1) corrosion rate (c.r) = 0.43* l cor where mpy = milli – inchs per year lcor = corrosion current density ( 2 / cma ) d = density of corroding species (g/cm 3 ) c.r= corrosion rate wt.= weight results and discussion figure 1 shows the microscopic tests that the microstructure of medium carbon steel as presented by specimens of groups (a, b, and c). specimens group (a) consist of ferrite and pearlite and the microstructure of the specimens groups (b, and c) consist of cementite which forming with ferrite a matrix called martensite. baianite in group (b) while sample (c) consist of tempering martinsied. these results agree with the results obtained by adnan calic [8] which study the cooling rate of the microstructure. this microstructure has affected on the results of the corrosion rates. figure 3 shows the relationship between the cathode and anodic behavior after polarization test, the corrosion results are shown in table 3 we see an increasing in corrosion rate of all specimens group at velocity (1m/min) this is because the ferrite which combined with the dissolved oxygen in sea water causes iron oxide which known as rust while this rate decreased as the velocity increased to (2 and 3) m/min, this is because the movement of the liquid prevents the formation of deposits and ions gathering on cathode pole where corrosion can easily develop [6]. corrosion rate for specimen (c) gives the best corrosion resistance because of the transformation of returned ustaniate by quenching to cementite. while specimen ( b) gives higher corrosion rate comparing with (c) because of the tempering temperature (350°c ) and slow cooling was higher than the tempering of specimen (c) tempering temperature(150°c) which causing forming of ferrite which contributed in corrosion forming conclusions 1heat treatment improves the corrosion resistance by increasing the combination of iron with carbon reducing by that the combination of iron with oxygen which produces rust. 2tempering by re-heating at 150°c for 1 hour then cooling in air gives better results in corrosion resistance than re-heating at 350°c or quenching heat treatment because all returned ustaniate by quenching to cementite 3increasing of sea water velocity contributed in decreasing the corrosion rate because of reducing the assembling of ions on cathode pole references [1] alstom, bosch, "corrosion of carbon steel"/key to metals steel, 2000. [2] article," steel corrosion", corrosion doctors, //file:h:/steel corrosion [3] adnan calik, “effect of cooling rate on hardness and microstructure of aisi 1020, aisi 1040 and aisi 1060 steels” international journal of physical sciences vol. 4 (9), pp. 514-518, september, 2009. [4] annual book of astmstandards, standard practice for calculation of corrosion rates and related information, g102-89,vol. 03.02, 2004. ‘ al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 34 [5]bangaru nvr, sachdev ak “influence of cooling rate on the microstructure and retained austenite in an intercritical annealed vanadium containing hsla steel. metallurgical and mater. trans. a, 13:11, 1982 [6]christina vargel," corrosion of aluminum", elsevire puplishing 2004 [7]kamilia gruskevica,kristina tihomirova, talis juhna, stein w. qstehus" influence of water velocity and nom composition on corrosion of iron pipes, riga technical university confrence, 2010 [8]m.b.ndaliman, "an assessment of mechanical properties of medium carbon steel under different quenching media", auj.t 10(2)100-100,oct,2006. [9]qiao zx, liu yc, yu lm, gao zm “ effect of cooling rate on microstructure formation and hardness of 30crnimo steel. app. phy. a.95, 917, 2009 [10]w. r. osório l. c. peixoto, l. r. garcia, a. garcia" electrochemical corrosion response of a low carbon heat treated steel in a nacl solution", materials and corrosion volume 60, issue 10, pages 804–812, october 2009 table 1 chemical analysis of ck45 wt% c si mn p s cr mo ni standard value 0.4-0.5 0.4 0.5-0.8 0.035 0.035 0.4 0.1 0.04 actual value 0.42 0.02 0.573 0.002 0.002 0.051 0.018 0.077 table 2 categorization of test specimens table 3 corrosion test result corrosion rate (m.p y.) i core 2 μa/cm e core (mv) velocity m/min specimen 21.846 49.65 -619.1 1 a 15.96 36.28 -627.4 2 a 8.87 20.11 -646.1 3 a 11.49 26.12 -618 1 b 9.81 22.31 -610.5 2 b 8.95 20.36 -606.3 3 b 3.36 8.25 -518 1 c 1.744 3.79 -519.3 2 c 1.0296 2.34 -560 3 c specimen symbol condition of specimens a base metal b re-heating at 350°c for 1 hour and cooling in air (tempering) c re-heating at 150°c for 1 hour and cooling in air (tempering) http://onlinelibrary.wiley.com/doi/10.1002/maco.v60:10/issuetoc corrosion resistance of tempered heat treated carbon steel ck45 in sea water at different velocities 34 a b c figure 1 microstructure of test specimens figure 2 the electrochemical corrosion unit al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 34 -5.00 -4.00 -3.00 -2.00 current density (ma/cm2) -800.00 -700.00 -600.00 -500.00 -400.00 p o te n ti a l (m v ) -3.00 -2.00 -1.00 0.00 current density (ma/cm2) -800.00 -700.00 -600.00 -500.00 -400.00 p o te n ti a l (m v ) figure 3 electrochemical behavior polarization for all specimens at (1)m/min. specimen a at 1 m/min specimen b at 1 m/min specimen c at 1 m/min corrosion resistance of tempered heat treated carbon steel ck45 in sea water at different velocities 45 -4.00 -3.00 -2.00 -1.00 0.00 current density (ma/cm2) -700.00 -600.00 -500.00 -400.00 -300.00 p o te n ti a l (m v ) -2.50 -2.00 -1.50 -1.00 -0.50 0.00 current density (ma/cm2) -800.00 -700.00 -600.00 -500.00 -400.00 p o te n ti a l (m v ) figure 3 electrochemical behavior polarization for all specimens at 2 m/min. -4.00 -3.00 -2.00 -1.00 0.00 current density (ma/cm2) -800.00 -700.00 -600.00 -500.00 -400.00 p o te n ti a l (m v ) specimen a at 2m/min specimen b at 2m/min specimen c at 2m/min al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 45 figure 3 electrochemical behavior polarizations for all specimens at 3 m/min. -4.00 -3.00 -2.00 -1.00 0.00 current density (ma/cm2) -800.00 -700.00 -600.00 -500.00 -400.00 p o te n ti a l (m v ) specimen a at 3m/min specimen b at 3m/min specimen c at 3m/min al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 332 theoretical and experimental investigation of friction stion stir welding for copper alloy abstract friction stir welding (fsw) is a relatively new solid-state joining process. this joining technique is energy efficient. in particular, it can be used to join highstrength aerospace aluminum alloys and other metallic alloys that are hard to weld by conventional fusion welding. in this paper the investigation is made on friction stir welding process for joining of copper alloy. friction stir welding experiments was performed using different pins (pin with straight boundary and pin with curved boundary). welding joints efficiencies were found for each set. mechanical and microstructural analysis has been performed experimentally on the welding zone. nonlinear numerical models was built in ansys software to simulate the thermal history of a workpiece undergoing friction stir welding by a moving heating source. an accurate prediction of temperature fields is evident. exclusive result for effect of rotating a friction stir tools with respect to boundary conditions on stress-strain curves is presented. the results shown that the friction stir welding with pin of curved boundary is more efficient than that of straight boundary . keywords: friction stir welding ,copper alloy, finite element method, ansys software, tensile test, microstructure دراسة نظرية وعملية للحام االحتكاكي لسبائك النحاس asst. prof. dr. hani aziz ameen technical college – baghdaddies and tools eng. dept ahmed hadi abood technical collegealmusaibpumps eng. dept nabeel shallal thamer engineering college -al-qadisiya university al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 333 الخالصة تعتبر عملية اللحام االحتكاكي من اكفأ عمليات اللحام والتي تستعمل لربط المعادن مثل االلمينيوم والمعادن ( fsw) يلحام االحتكاكاتطبيق في هذه الدراسة تماالخرى والتي من الصعوبة لحامها بالطرق التقليدية . الدبوس بحواف مستقيمة والدبوس بحواف سبائك النحاس من خالل تصميم وتصنيع نوعين من األدوات )ل على منطقة يل ميكانيكية ومجهرية الوقد تم إجراء تحوقد وجد ان كفاءة اللحام جيدة لكال الحالتين (. منحنية لمحاكاة التأثيرات الحرارية خالل عملية اللحام ببرنامج االنسز وقد تم انشاء موديل غير خطي .اللحام االنفعال (-)االجهادمنحنى وقد تم الحصول على نتائج الخواص الميكانيكة . متنقل يمصدر حرارباستخدام وقد بينت النتائج ان اللحام باستخدام دبوس بحواف منحنية هو اكثر كفاءة من لكال االوادت التي تم تصنيعها. الحواف المستقيمة . symbols kx, ky, kz ……… thermal conductivity in x, y, and z directions x,y,z …………… coordinates ………………… density t ………………… temperature t ……………… time q ………………… rate of heat generation cp ……………. … specific heat ……………........ slip factor that compensate for tool/material relative velocity ……………….. friction coefficient rs ……………… shoulder radius rp ……………… pin radius lp ……………… pin length p ……………….. interfacial pressure ……………….. angular speed vt ………………. tool speed fsw ……………. friction stir welding li ……………….. initial position lw ………………. finial position introduction friction stir welding is one of the new method of welding developed nowadays, many researches in the literature about friction stir welding of aluminum and it’s alloys, researches about copper and it’s alloys are limited. in this welding process, a rotating welding tool is driven into the material at the interface of, for example, two adjoining plates, and then translated along the interface. cemal meran (2006), applied friction stir welding procedures to brass plates with 3 mm in thickness in different rotation and welding speeds. obtained welded joints subjected about physical virtual, mechanical tests and microstructure investigations and the results had been evaluated. sun and fujii (2010), obtained the process window for friction al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 334 stir welding of commercially pure copper. hwang et al., (2010), studied the thermal history of a workpiece undergoing friction stir welding (fsw) involving butt joining with pure copper c11000, the appropriate temperatures for a successful fsw process were found to be between 460°c and 530°c. these experimental results and the process control of temperature histories can offer useful knowledge for a fsw based process of copper butt joining. several investigations (cao and qi (1998), chen and kovacevic (2003) , zhu and chao (2004)) of the thermal stress distribution in friction stir welds were carried out by finite element method (fem). lai and sandstrom(2012), investigated the numerical simulation of residual stresses for friction stir welds in copper canisters and obtained the maximum tensile stress, whether it is predicted by the finite element method. in this research, it was pointed on friction stir welding capability especially copper alloy plates which are 4 mm in thickness and using two types of pins. model description the temperature distribution varies in time and space, hence a three dimensional, transient, isotropic with moving heat source model was used to simulate fsw, the general heat transfer equation (nandan et al, 2006) is: ̂ (1) where ̂ ……….. single or combination of material properties = total frictional heat of shoulder will be [nandan et al, 2007] ∫ ( ) (2) similar concept, heat generated by lateral surface of the pin is : ( ) (3) the total heat generated from the tool ( ) ( ) (4) during the process the tool travels at a constant speed (vt). the motion was simulation by changing heat source location as shown below according to the following equation (ridha, 2009), as shown in fig.(1). for (5) where al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 335 ………….. time required for the tool to travel from location xi to xi+1 the three dimensional element solid5 was used in the 3-d coupled-field solid analysis, the element has eight nodes with thermal and structural degree of freedom, displacement and temperature at each node. it is applicable to a three dimension steady-state or transient thermalstructure analysis (ansys help v.11). according to the above equations and modeling of heat source movement, the following subroutine is made and imported to ansys code in order to achieve the moving heat source. subroutine of moving heat source !load step 1, initial conditions 25° c time,0.001 deltim,0.001,0.001,0.001 tunif,25, solve !load step 2..... , apply moving heat flux j=1 *do,i,195,85,-5 time,j deltim,0.11,0.11,0.11, sfedele,i+5,6,hflux sfe,i,6,hflux, ,qw, , , eplot solve j=j+1 *enddo experimental work the nominal composition of the copper base material used in this work was mention in table(2). the copper plate dimensions of 200mm (l), 50mm (w), 4mm (t) was used in the present study. the copper plates were clamped rigidly on backup plate to produce butt joint using the fsw technique as shown in fig. 4. tool geometry the tool geometry is the most influential aspect of process development. the geometry play a critical role in material flow and in turn governs the traverse rate at which fsw can be conducted. an fsw tool consists of a shoulder and a pin as shown in fig.(2) (nandan et al, 2008). al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 336 in our research the chemical composition and the hardness of the tool is provided from the special institute of the engineering industry as shown in table (1). two types of tools pins are designed and manufactured in this work as shown in fig.(3), which are used to implement the fsw. copper alloy copper which has much higher thermal diffusivity than steel cannot easily be welded by conventional fusion welding techniques. the base metal used in this work was 4mm thick copper alloy plate, whose chemical composition is provided from the special institute of the engineering industry as in table (2) welding process the samples of 50mm x 200mm were longitudinally fixed using vertical milling machine as shown in fig.(4) (muna et al, 2011). the welding tool is composed of shoulder and pin (fig.(3)). the welding tool is rotated at high speed into the joint line between two plates to be welded together (zhili feng et al,2003). this stirring action of the rotating tool yields a heavily deformed alloy. the frictional heat generated by the welding tool makes the surrounding material softer and allows the tool to move along the joint line. the softened material starts to flow around probe resulting in transferring of material from the leading edge of the tool to the side (maria posada et al,2003). in this study, the welding parameters such as tool speed of (1000 rpm) and travel or welding speed of (69 mm/sec ) are constants. samples preparation for microstructure the samples made from a cross section of the fsw joints and base alloy were ground, polished and etched and observed under optical microscope in sequences steps (muna et al, 2011). wet grinding operation with water was done by using emery paper of sic with the different grits of (220,320,500, and 1000). polishing process was done to the samples by using diamond paste of size (1µm) with special polishing cloth and lubricant (diamond paste). they were cleaned with water and alcohol and dried with hot air. etching process was done to the samples by using etching solution which is composed of (99% h2o+1%hf).then the samples were washed with water and alcohol and dried. the friction stir welded joint samples al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 337 were examined by nikon me-600 optical microscope provided with a nikon camera, dxm-1200f. mechanical test tensile specimens were machined according to the astm e8m-04 , specimen geometry is shown in fig.(5), it shows standard dimensions to be specified. for plate after welding, all specimens were taken normal to the welding line. results and discussion friction stir welding is a fully mechanized process. fsw is a difficult and challenging problem because involves complex interactions between varieties of simultaneous processes. the interactions affect the heating and cooling rates, plastic deformation and flow, dynamic recrystallization phenomena and the mechanical integrity of the joint. fig.(6) shows the copper welded plate by fsw using pins type a and b. the result of heating, stirring (in case of fsw) and cooling in the welding process is the strain that occur in the weld metal and base metal regions near the weld. the strain produced is accompanied by plastic upsetting. the stresses resulting from these strains combine and react to produce internal forces (i.e. residual stresses). these forces are reasonable for changing structure properties. to investigate the effect of different pins (a and b) on the tensile strength of friction stir welded plate, a series of tensile tests were conducted for each joint. the results were compared with tensile properties of base metal and the welding efficiency based on ultimate tensile strength for each friction stir welded plate have been calculated. fig.(7) shows the stress-strain curve for the copper alloy plate. fig.(8) shows the stress – strain curve for welded plate using pin type – aand fig.(9) shows the stress – strain curve for welded plate using pin type – b. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 338 table(3) shows the mechanical properties of the fsw copper alloy plate using different pins tools type a and type b. the most important part of modeling welding process is the thermal analysis. previous researchers have simulate heating load by a heat on all welding line and keep this load for a specific period of time after which the heating load was set to zero and cooling take place. the relative motion between heat source and plate is used in the present work, in this method the movement of heating load takes place by changing location of it, i.e. the tool location was changed according to eq.(5). moving heat source using ansys requires high programming skills (subroutine of moving heat source is illustrated in article model description). fig.(10) shows contour of temperature variation through fsw process. the thermal process and stress evolution process are coupled. where results of the thermal field will be the cause of the driving force that resulting in thermal stresses while thermal solution will not depend on the stress solution. in this case the temperature distribution, which varies in time and space, is loaded into the stress analysis as a predefined field. temperature fields affect mechanical fields through thermal expansion and temperature dependent material properties. thermal expansion or contraction due to transient application of temperature gradient is usually the dominant concern in thermal stress analysis. fig.(11) shows contour of thermal variation through fsw process. fig.(12) shows the microstructures of the fsw for copper alloy using pins type a and b. according to microstructural observation in this research ,the grain sizes in the weld nugget are significantly smaller than the parent metal and this can be attributed to the mechanical forces operative during welding which cause both refinement and re –alignment of the matrix grains and should be beneficial with respect to various mechanical properties. this is due to the temperature difference between the tool shoulder side and base size and the tool centerline and the edge of the weld nugget which causes the grain size variations. during fsw process only coarser precipitates could nucleate and grow but not finer ones. this aids in the formation of passive film, which remains more intact on surface of the sample. the microstructure of the copper weld consists of different zones such as tmaz, haz and parent metal. the microstructure of the haz has been observed to be finer than the parent metal due to dynamic recrystallization. in the haz few coarse grains presence were observed. conclusions the main important conclusions which can be drawn from this work are: al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 339 1. the butt joining of copper was successfully carried out using fsw technique via straight boundary pin and curved boundary pin. the results shown that the friction stir welding with pin of curved boundary is more efficient than that of straight boundary and the grain size in the welded zone in case of using curved boundary pin has more refine than that of straight pin, i.e. was developed for microstructural of metallic materials 2. for a given tool rotational and traveling speeds peak temperature increases as tool moves along welding joint because of heat accumulation within the workpiece. 3. modeling of friction stir welding process using moving heat source is more reasonable than the published model. 4. the present study has demonstrated that normal copper can be successfully joined by fsw. references cemal meran, “the joint properties of brass plates by friction stir welding”, materials and design, no. 27, p. 719–726, 2006. y.f. sun, h. fujii, “investigation of the welding parameter dependent microstructure and mechanical properties of friction stir welded pure copper” , materials science and engineering a , no.527, p. 6879–6886, 2010. y.m. hwang, p.l. fan, c.h. lin, “experimental study on friction stir welding of copper metals” , journal of materials processing technology, no. 210, p. 1667– 1672, 2010. lai-zhe jin, rolf sandstrom, “numerical simulation of residual stresses for friction stir welds in copper canisters”, journal of manufacturing processes, no. 14, p. 71–81, 2012. cao yj, qi x. “thermal and thermo-mechanical modeling of friction stir welding of alumimium alloy 6001-t6”. j. mater process manuf. sci., no.7, p.215–33, 1998. chen cm, kovacevic r. “finite element modeling of friction stir welding-thermal and thermomechanical analysis” int. j. mach. tools manuf., no.43, p.1319 –26, 2003. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 340 zhu xk, chao yj. “numerical simulation of transient temperature and residual stresses in friction stir welding of 304l stainless steel”, j. mater process technol.,no.146, p.263–72, 2004. nandan r., roy g.g. and debroy t. “ numerical simulation of three dimensional heat transfer and plastic flow during friction stir welding” metallurgical and materials transactions a, vol. 37a, p. 1247-1269, 2006 nandan r., roy g.g. , lienert t.j. and debroy t. “ three dimensional heat and material flow during friction stir welding of mild steel” acta materialia, no.55 , p.883-895, 2007. s. d. ridha , “ theoretical and experimental study for measurement of residual stresses induced by friction stir welding and investigation of stress relieve by vibration in aluminum alloy”, ph.d. thesis, baghdad university, 2009. ansys ver.11 help, “ansys elements reference” . r. nandan, t. debroy, h.k.d.h. bhadeshia “recent advances in frictionstir weldingprocess, weldment structure and properties”, progress in material science, vol. 53, p. 980-1023, 2008. muna k. abbass, hani aziz ameen and khairia salman hassan “effect of heat treatment on corrosion resistance of friction stir welded aa 2024 aluminum alloy”, american journal of scientific and industrial research, vol. 2, no.2, p. 297-306, 2011. zhili feng , sidney diamond and philip s. sklad , " friction stir processing of advanced materials", high strength weight reduction materials, progress report ,p.101-107, 2003. maria posada, p. jennifer nguyen, r. david forrest, j. jobnnie branch and robert denale, “friction stir welding advances joining technology”, special issue ampiag, quarterly vol. 7, no.3 , p.13-20, 2003. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 341 table (1) chemical composition and the hardness of the tool hardness hrc hardness h b co mo v p cr c grade 60 62 207 255 --- 0.3 1 – 1.4 17.5 19 3.8 – 4.4 0.7 – 0.8 h.s.s r18 (russia) table (2) chemical composition of the used copper alloy cu% al% sn% p% as% s% zn% c% mg% pb% fe% si% sample bal. 0.001 0.001 0.013 0.006 0.006 28 0.003 0.001 0.004 0.029 0.001 metal segment table (3) mechanical properties young modules (e) [gpa] yield stress ( ) [mpa] copper alloy 130 244 welded plate with tool type a 102 197 welded plate with tool type b 135 163 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 342 fig.(1) modeling of heat source movement fig.(2). tools design (nandan et al, 2008) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 343 (a) straight boundary pin (b) curved boundary pin fig.(3) tools type a and b, which are designed, manufactured and used in the fsw (all dimensions in mm) a b al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 344 fig.(4) vertical milling machine for fsw fig.(5) tensile test specimen al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 345 fig.(6) copper welded plate by fsw using pins type a and b. pin type a pin type b al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 346 fig.(7) stress-strain curve for the copper alloy plate al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 347 fig.(8) stress – strain curve for welded plate using tool type – a fig.(9) stress – strain curve for welded plate using tool type – b al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 348 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 349 fig.(10) contour of temperature variation through fsw process al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 350 fig.(11) contour of thermal stress variation through fsw process. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 351 haz zone (pin type a) haz zone (pin type b) welded zone (pin type a) welded zone (pin type b) fig.(12) microstructures of the fsw for copper alloy using tools type a and b prediction of surface roughness in turning machine by taguchi method al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 326 prediction of surface roughness in turning machine using taguchi method dr.abbas fadhil ibrahim abbasfadhel_2006@yahoo.com received 16 october 2014 accepted 18 may 2015 abstract this paper investigates the effect of process parameters (approach angle, nose radius, cutting speed and feed rate) on surface roughness in turning machine. the experiments was conducted based on taguchi’s l8 orthogonal array and assessed with analysis of variance and signal to noise ratio. according to this, it was observed that surface roughness correlates negatively with nose radius and positively with approach angle. the ability of the independent values to predict the dependent values was 95.1% for mean. minimum surface roughness was predicted as 4.207 μm with approach angle 5°, nose radius 1.5mm, cutting speed of 455 rpm and feed rate of 0.19 mm/rev. from analysis of variance anova, the feed rate was the most significant parameter for minimum surface roughness, cutting speed was next significant parameter for minimum surface roughness, then nose radius, while approach angle was the last. keywords: surface roughness, turning, taguchi method, anova, nose radius. التنبؤ بالخشونة السطحية في عملية الخراطة باستخدام طريقة تاكوجي الخالصة: ، نصف قطر مقدمة الحد القاطع، سرعة القطع ومعدل االقترابيهدف البحث على التعرف على تاثير اعتبارات التشغيل مثل )زاوية ومصفوفة عمو ية يتم تقييمها مع 8l عتما على تاووجي اجريت باالاالختبارات التغذية( على الخشونة السطحية في عملية الخراطة. تحليل التباين ونسبة االشارة الى الضوضاء. طبقا" الى هذا يالحظ ان الخشونة السطحية ترتبط سلبيا" مع نصف مقدمة الحد القاطع 7.2.4% . ان اقل خشونة سطحية متنبأة وانت..59وايجابيا" مع زاوية االقتراب. قابلية القيم المستقلة على التنبؤ بالقيم المعتمدة وانت 5... ورة بالدقيقة و معدل تغذية 799ملم،سرعة قطع 9.. رجة ،نصف قطر مقدمة حد قاطع 9مايكرومتر مع زاوية اقتراب لثاني الذي يؤثر من تحليل التباين وان معدل التغذية هو االوثر تأثير ألقل خشونة سطحية ,سرعة القطع وانت هي المتغير اة.ملم/ ور على اقل خشونة سطحية , ومن ثم نصف قطر مقدمة الحد القاطع, بينما زاوية االقتراب وانت االخيرة من ناحية التأثير على الخشونة ..السطحية. ..............................................................................................................,.............................. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 327 1introducton: metal cutting is one of the most significant manufacturing processes in the area of material removal [chen, 1997]. black defines metal cutting as the removal of metal from a workpiece in the form of chips in order to obtain a finished product with desired attributes of size, shape, and surface roughness [black, 1979]. turning is the processes used to remove material to produce specific products of high quality. among various process conditions, surface finish is central to determining the quality of workpiece [shin, 1995] .the tool edge geometry has an important influence on the process parameters, such as the cutting forces, distributions of temperature and stresses on the tool face and the chip morphology. these effects in turn affect the changes in chip flow, machined surface integrity, tool wear resistance, and tool life [yen, 2004]. the various angles in a single-point cutting tool have an important function in machining operations. cutting-edge angles affect chip formation, tool strength and cutting forces to various degrees [jones, 1999]. cutting condition in a machining operation consist of cutting speed, feed rate and depth of cut. the effects of cutting speed and feed rate on the surface roughness are different with deferent change in cutting condition and materials [shin, 1995, hatem, 2011]. the surface roughness depending upon the cutting condition, essentially the cutting speed, the change of cutting speed give different results with increasing the cutting speed leads to improvement in the surface finish of turning process. the second factor which effected upon the surface roughness is feed rate, because of the elastic and plastic deformation on the surface layer reducing the feed rate helps to a chive a better surface quality. while the change in the depth of cut gives a less effect on the surface roughness, than on the cutting speed and feed rate [shin, 1995, kalpakjian, 2006, groover, 2002]. the tool nose radius is very critical part of the cutting edge since it produces the finished surface, if the nose is made to a sharp point the finish machined surface will usually be unacceptable and the life of the tool will be short[mccauley, 2000]. if other factors such as the work material, the cutting speed, and cutting fluids are not considered large nose radius will give better surface finish and will permit a faster feed rate to be used [trent, 1984]. avery large nose radius can often be used but a limit is some times imposed because the tendency for chatter to occur is increased as the nose radius is made larger prove that most cutting conditions , experimental and theoretical (ra) values mach very well, except at low value of feed .also one of the structural modes of the machine tool – workpiece system is excited by cutting forces initially away surface finish left during the previous revolution in turning is removed during the succeeding revolution which also leaves a wavy surface owing to structural vibrations[shather, 2009]. taguchi method has been widely used in engineering analysis, and is a powerful tool to design a high quality system. moreover, taguchi method employs a special design of orthogonal array to investigate the effects of the entire machining parameters through small number of experiments. the array forces all experimenters to design almost identical experiments [brar, 2011]. in the present research determination the effect of process parameters approach angle and nose radius for cutting tool, cutting speed and feed rate for turning machine on surface roughness in turning machine and then predict for surface roughness by using taguchi method. 2. experimental procedure: 2.1 material: the workpiece used in this work was made of stainless steel with dimensions of 150mm length and 40mm width. the chemical compositions are shown in table 1. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 328 2.2 machine: the experiment was performed by using a turning machine model (harrison m300) as shown in figure 1. 2.3 cutting tool: the cutting tool was made of carbide, used with different approach angle (table 2); this carbide has triangle shape and used three carbides insert with deferent nose radius (table 2) as shown in figure 2. 2.4 process parameters: the machining parameters, such as approach angle, nose radius, cutting speed and feed rate were varied to determine their effects on the surface roughness with fixed depth of cut at 1mm. the experiments were designed to study the effects of these parameters on response characteristics. table 2 shows the various levels of process parameters. 3analysis by taguchi method: the experiments were planned by using the parametric approach of the taguchi’s method. the response characteristic data was provided in table 3. the standard procedure to analyze the data based on s/n ratio, as suggested by taguchi, was employed. the average values of the s/n ratio of the quality/response characteristics for each parameter at different levels were calculated from experimental data. the response parameters (surface roughness), are of “smaller is the better” type of machining quality characteristics; hence the s/n ratio for these types of responses was given by equation (1) [gupta, 2011].          n i i y n ns 1 2 )( 1 log10/ ; i=1, 2,………n (1) where n: number of reading test. yi: output variable value (ra). 3.1 taguchi orthogonal array: one of the basic elements of taguchi method is orthogonal array (oa). to select an appropriate orthogonal array for the experiments, the total degrees of freedom need to be computed. the degrees of freedom are defined as the number of comparisons between process parameters that need to be made to determine which level is better and specifically how much better it is [gupta, 2011]. there is minimum number of experimental trials required in orthogonal array, so it is more efficient in handling large number of factor variables than traditional factorial design. additionally, the orthogonal array allows determination of the contribution of each quality influencing factor [tongchao, 2010]. in the present research, the standard taguchi orthogonal array of l8 (4 1 x 2 3 ) has been employed. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 329 3.2 analysis of variance anova: the anova is used to investigate the statistical significance of the process parameter affecting the response. therefore, the factor that has more percentage contribution in the process will be identified in analysis. the ratio between the variance of the process parameter and of the error called as f test determines whether the parameter has a significant effect on the quality characteristic. the larger fvalue has more effect on the performance characteristics [chomsamutr, 2012]. anova table obtained using minitab program. 4results and discussion: table 3 represents the experimental results of various response characteristics according to taguchi l8 mixed orthogonal array. surface roughness for each experiment is measured using portable surface finish tester. various response characteristics, namely, ra in micrometers. the average (mean) of these characteristics and s/n ratio (in decibels) are shown for each characteristic. the r square pieces (the ability of the independent values to predict the dependent values) is 95.1% for mean (surface roughness). the main purpose of the analysis of variance (anova) is to investigate and indicate the designed parameters, which significantly affect the quality characteristic. in the analysis, the sum of the square deviation is calculated from the value of s/n ratio by separating the total variability of s/n ratio for each control parameter. this analysis helps to find out the relative contribution of finishing parameter in controlling the response of this process. the “p%” value (percent of contribution) in tables 4 and 5 shows the effectiveness of each parameter toward influencing the related response characteristics within the specified range. from table 4, it is concluded that the feed rate (parameter d) is the most significant parameter for minimum ra. cutting speed (parameter c) is next significant parameter for minimum ra , then nose radius (parameter b), while approach angle (parameter a) was the last. from table 5, it is concluded that the cutting speed (parameter c) is the most significant parameter for maximum s/n ratio. feed rate (parameter d) is next significant parameter for maximum s/n ratio, then nose radius (parameter b) , while approach angle (parameter a) was the last. figures 3and 4 shows the plot of the means of the surface roughness and the means of s/n ratio. it is clear that the optimal parametric combination for minimum ra is a1 b2 c1 d2, i.e., at 5° approach angle, 1.5mm nose radius, 355 rpm cutting speed and 0.19mm/rev feed rate. it is suggested that the parametric combination within the considered range as mentioned above give lowest surface roughness height ra for finishing of workpiece. 5conclusions: the main conclusions deduced from the present work can be summarized as follows: 1the ability of the independent values to predict the dependent values) is 95.1% for mean. 2the feed rate (parameter d) is the most significant parameter for minimum ra. 3the cutting speed (parameter c) is the most significant parameter for maximum s/n ratio. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 330 4the optimal parametric combination for minimum ra is a1 b2 c1 d2, i.e., at 5° approach angle, 1.5mm nose radius, 355 rpm cutting speed and 0.19mm/rev feed rate. 5the optimal parametric combination for s/n is a1 b2 c1 d2, i.e., at 5° approach angle, 1.5mm nose radius, 355 rpm cutting speed and 0.19mm/rev feed rate. 6references: [1]. brar b.s., walia r.s., singh v.p., singh mandeep , “development of a robust abrasive flow machining process setup”, national conference on advancements and futuristic trends in mechanical and materials engineering ,2011. [2]. christopher mccauley (machinery’s hand book guide 26) ,2000. [3]. ding tongchao, zhang song, wang, yuanwei and zhu, xiaoli, “empirical models and optimal cutting parameters for cutting forces and surface roughness in hard milling of aisi h13 steel”, international journal advanced manufacturing technology, volume: 51, issue: 1, pages: 45-55, 2010. [4]. e.m.trent (metal cutting) second edition , 1984. [5]. gupta, a., singh, h. and aggarwal, a., “taguchi-fuzzy multi output optimization (moo) in high speed cnc turning of aisi p-20 tool steel”, expert systems with applications, volume: 38, issue: 6, pages: 6822-6828, 2011. [6]. huda hatem, “study the effect of cutting conditions for turning process on the machined surface”, nahrain university, college of engineering journal (nucej) vol.14 no.1, pp.61-66, 2011. [7]. j. c. chen and r. a. smith., "experiment design and analysis in understanding machining mechanisms , journal of industrial technology, vol. 13, no. 3, pp. 15-19, 1997. [8]. j. t. black, " flow stress model in metal cutting , journal of engineering for industry, vol. 101, no. 4, pp. 403-415, 1979. [9]. k. chomsamutr and s. jongprasithporn, “optimization parameters of tool life model using the taguchi approach and response surface methodology”, ijcsi international journal of computer science issues, volume: 9, issue 1, no. 3, pages: 120-125, 2012. [10]. m. p. groover, "fundamentals of modern manufacturing", lehigh university, second edition, 2002. [11]. nigel jones, "'intelligent' tooling make its presence felt", machinery and production engineering, 157, 3980: pp. 28-30, 1999. [12]. saad kariem shather, “studying the effect of tool nose radius on workpiece run out and surface finish”,eng.&tech. journal,vol.27,no.2,2009. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 331 [13]. serope kalpakjian, "manufacturing engineering and technology", fifth edition, 2006. [14]. y. c. shin and s. a. coker, "surface roughness measure by ultrasonic sensing for in process monitoring", journal of engineering for industry, vol. 117, pp. 439, 1995. [15]. y.c. yen, a. jain, t. altan, “a finite element analysis of orthogonal machining using different tool edge geometries,” j. mater. process. technol., vol. 146, pp. 72-81, february, 2004. table (1): chemical compositions of workpiece. [aisi] element cr% ni% p% mn% c% fe% weight 11.5 0.03 1.0 0.5 0.15 remain table (2): process parameters at different levels no. parameter level 1 level 2 level 3 level 4 1 approach angle(degree) a 5 10 15 20 2 nose radius (mm) b 0.5 1.5 / / 3 cutting speed (rpm) c 355 455 / / 4 feed rate (mm/rev) d 0.16 0.19 / / table (3): the l 8 (4 1 x2 3 ) oa (parameters assigned) with experimental results of various response characteristics. no a b c d ra1(µm) ra2(µm) ra3(µm) s/n ra mean(µm) ra predict(µm) 1 5 0.5 355 0.16 4.32 4.65 4.56 -13.0877 4.51 4.41125 2 5 1.5 455 0.19 3.98 4.33 4.05 -12.3038 4.12 4.21875 3 10 0.5 355 0.19 5.25 5.41 4.64 -14.1697 5.10 5.19875 4 10 1.5 455 0.16 4.87 4.96 5.77 -14.3463 5.11 5.10125 5 15 0.5 455 0.16 5.01 5.42 5.50 -14.5090 5.31 5.40875 6 15 1.5 355 0.19 5.32 5.10 5.09 -14.2716 5.17 5.07125 7 20 0.5 455 0.19 5.29 5.22 5.48 -14.5364 5.33 5.23125 8 20 1.5 355 0.16 5.12 4.78 4.77 -13.7910 4.89 4.98875 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 332 table (4): analysis of variance for mean taguchi orthogonal array (toa) source degrees of freedom df sum of squares ss mean sum of squares ss mean square ms f value (ms /error) percent of contribution p a 3 1.07345 1.07345 0.357817 5.84 0.293 b 1 0.11520 0.11520 0.115200 1.88 0.401 c 1 0.00500 0.00500 0.005000 0.08 0.823 d 1 0.00125 0.00125 0.001250 0.02 0.910 residual error 1 0.06125 0.06125 0.061250 total 7 1.25615 table (5): analysis of variance for sn ratios taguchi orthogonal array (toa) source degrees of freedom df sum of squares ss mean sum of squares ss mean square ms f value (ms /error) percent of contribution p a 3 3.64678 3.64678 1.21559 5.59 0.299 b 1 0.38238 0.38238 0.38238 1.76 0.411 c 1 0.00561 0.00561 0.00561 0.03 0.899 d 1 0.01025 0.01025 0.01025 0.05 0.864 residual error 1 0.21743 0.21743 0.21743 total 7 4.26246 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 figure (1): turning machine model (harrison m300) figure (2): holder and insert al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 334 2015105 5.2 5.0 4.8 4.6 4.4 1.50.5 455355 5.2 5.0 4.8 4.6 4.4 0.190.16 a m e a n o f m e a n s b c d main effects plot for means data means figure (3): main effects plot for means 2015105 -12.5 -13.0 -13.5 -14.0 -14.5 1.50.5 455355 -12.5 -13.0 -13.5 -14.0 -14.5 0.190.16 a m e a n o f s n r a t io s b c d main effects plot for sn ratios data means signal-to-noise: smaller is better figure (4): main effects plot for signal to noise ratios al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 415 applied the analogue system in drip irrigation system (looped with carrier network) eman mehdi al-mousawi assistant lecturer engineering college university of babylon abstract drip irrigation system can apply frequent and small amounts of irrigation water at many points of a field surface/subsurface near the plants with drip irrigation, plant water and fertilizer requirements can also be applied to the plant root zone with minimum losses, maintaining steady moisture in the soil profile. in addition, drip irrigation systems have the advantage of fitting difficult topography. the research studied drip irrigation system (looped with carrier network) in analogue system, to generate data by using analogue system, it an electrical board is constructed to simulate the field network. that means to use thermal wires to simulate the laterals, and resistances to simulate the emitters. a relationship has been concluded through the derived equation between the emitters discharge and resistance voltage. comparing both equations that are derived from the field, a new relative equation has been concluded; with a new relative reflect the head and current relationships. the analogue results confirm the field results by using three types of emitters (turbo, adjustable flow drippers and longpath emitter). the field results took from studied at 2010. keywords: drip irrigation, pressure, analogue, emitter, manufacture coefficient غلقه مع خط ناقل)لمتطبيق نظام المحاكاة الكهربائي على نظام الري بالتنقيط (للشبكه ا الخالصه الحقل نقاط معظم يغطي بالتنقيط الري نظام و الحقل الى الماء من ومتكرره صغيره كميات اضافةهو بالتنقيط الريّ نظام يوصل بالتنقيط الري نظام ان كذلك الجذريه المنطقه ضمن رطبة التربه تبقى بحيث الجذريه المنطقه قرب التربه سطح وتحت فوق al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 416 ذات لالراضي مالئم بالتنقيط الري نظام ان كما االخرى الري بنظم مقارنه المياه كميات ناحية من خسائر بأقل النبات الى الماء حيث البيانات لتوليد) ناقل خط مع حلقي( بالتنقيط ري نظام على كهربائي محاكات نظام تطبيق البحث تناول. المختلفه الطبوغرافيه خطوط لتمثيل حراريه اسالك بأستخدام الحقليه الشبكه ربط يحاكي بربط كهربائيه لوحه عمل خالل من الحقليه الشبكه تمثيل تم بفروق التصاريف تشبيه لخال ومن والتيارات الجهد فروق قراءة وتمت المنقطات لتمثيل الكهربائيه المقاومات واستعملت المنقطات لكل معادله خالل من الكهربائيه اللوحه في والتيار الحقليه الشبكه في الضغط بين تربط عالقه استنتاج تم بالتيارات والضغوط الجهد .2010 في سابقه دراسه من الحقليه البيانات اخذت حيث المستخدمه الثالثه المنقطات انواع من نوع معامل المصنع.تنقيط, ضغط, التمثيل, منقط, الداله:ري بال الكلمات ymbolss q: the discharge of emitter ( . a: a coefficient specific to each emitter, h: the pressure at the emitter (l), x: an exponent depends on the flow regime, v= voltage in the resistor (volt), i= current in the resistor (amber) b, y = constants r.v.v= relative variation of voltage r.v.q= relative variation of emitter discharge. introduction drip irrigation (also known as trickle irrigation, micro-irrigation, or low-volume irrigation) offers an excellent alternative to sprinkler irrigation for vegetable and small fruit growers. trickle irrigation systems typically use 30-50 percent less water than sprinkler systems and the water are rationed to the plants as they need it. this reduces evaporation, particularly on hot, windy days, and enables the grower to only water the desired plants and not the row alleys or roadways. weed control is therefore simplified, and workers are able to do fieldwork while the irrigation system is running. the system's almost continuous operation at low flow rates and operating pressures allow the grower to irrigate with lower-cost, smaller pumps through smaller, lightweight pipes which may deliver as little as 15 or 20 m3/m. the irrigation pumping requirement drops from the 7 to 4 m3/m per m2 at 50 to 40 psi typical for sprinklers to 5 to 2 m3/m per m2 at 20 to 6 psi for trickle irrigation systems. so 0.06 m3/m capacity water well solely dedicated to supplying 3 to 4 sprinklers may be used to trickle irrigate 2 to 4 acres of vegetables or small fruits, with enough extra capacity to meet normal household needs [robert a. schultheis, 2005]. according to [mizyed etal, 1989] drip irrigation system efficiency depends on application uniformity. in surface drip irrigation systems, uniformity can be evaluated by direct al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 417 measurements of emitter flow rates. the main factors affecting drip irrigation system uniformity are: (1) manufacturing variations in emitters and pressure regulators, (2) pressure variations caused by elevation changes, (3) friction head losses throughout the pipe network, (4) emitter sensitivity to pressure and irrigation water temperature changes, and (5) emitter clogging. (similarly and scicolone, 1998). hydraulics of sub-unit polyethylene tubing 25mm in diameter and larger is commonly used for trickle irrigation mainlines and sub mains. sizes of 25mm and less are used for laterals and micro-tubes. in order to achive optimum uniformity of emitter discharge, it is essential that the frictional head losses in laterals and mains be properly evaluated. the primary sources of head loss are pipe friction and losses caused by the emitter barbs [madramootoo, 1981]. [bralts et al, 1981] showed that the hydraulic and manufacturing variation of emitters can be statistically combined and included in the design equations for uniformity of single chamber drip irrigation laterals. [al-misned, 2000] found the estimation of energy losses due to emitter’s connection in trickle irrigation laterals was very important. since these losses had a direct effect on trickle irrigation system design, the study of these losses would lead to the improvement of system efficiency which would eventually result in conservation of water and energy. in his study, the problem of a lateral pipe with equally spaced emitters and uniform slope was evaluated. a computer program for estimating lateral discharge, emitter discharge and pressure head distribution along a lateral was developed. individual emitters were considered in discharge and pressure estimations along the lateral starting from the downstream reach of the pipe. the friction head loss between successive emitters was estimated using darcy-weisbach, s formula. the change of the velocity head, the changes of momentum along the lateral, and the loss due to emitter were also considered. as the emitter discharge and energy losses were evaluated, the corresponding pressure head at each emitter was estimated accordingly. the output results from the program were in close agreement with the experimental data obtained from published work. the program provides a simple and direct method to design trickle laterals taking into account all energy losses including emitter’s connection losses. emitters a rather exhaustive classification of emitters, their hydraulic and mechanical properties, and details of their construction are given by [krystal and k. zanker, 1974], [keller and karmeli, 1975]. emitters can be classified according to any one of several main characteristics. three categories were defined by [krystal and k. zanker, 1974]: orifice drippers, long path type of drippers, porous tubing. emitters are usually classified by the method in which they dissipate pressure or discharge characteristics [keller and bliesner, 1990].for example, there are long path, vortex, orifice, flushing, continuous flushing, and multi-outlet emitters. [solomon, 1979] stated that the efficiency of trickle irrigation systems depends on the uniformity of emission rates throughout the system. an important factor affecting this uniformity is the unit-to-unit variation between emitters. the design of an emitter, the materials from which it is made, and the care taken in the manufacturing processes affects the amount of such unit-to-unit variation that may be expected. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 418 [vanceleo, 2004] evaluated the application uniformity of subsurface drip distribution systems and the recovery of emitter flow rates. emission volume in the field and laboratory measured flow rates were determined for emitters from three locations and studied the effects of lateral orientation with respect to slope on emitter plugging. two different emitters were tested to evaluate slope effects on emitter plugging [types y and z]. the emitters were alternately spliced together and installed in an up and down orientation on slopes of 0, 1, 2, and 4% and along the contour on slopes of 1 and 2%. the emitters were covered with soil and underwent a simulated year of dosing cycles, and then flushed with a flushing velocity of 0.6 m/s. initial flow rates for the two emitter types were 2.38 l/hr with a coefficient of manufacture (cv) equal to 0.07. there was no significant difference in flow rates among slopes for type y emitters, but there was a significant difference between the 1% and 2 % contour slopes for type z emitters. application uniformity of three different laterals at each site was evaluated. sections of the lateral from the beginning, middle and end were excavated and emission volumes were recorded for each emitter. application uniformity of laterals ranged from 48.69 to 9.49%, 83.55 to 72.60%, and 44.41 to 0% for sites a, b, and c, respectively. mean emitter flow rates were 2.21, 2.24, and 2.56 l/hr for sites a, b, and c, respectively under laboratory conditions. application uniformity under laboratory conditions ranged from 70.97 to 14.91%, 86.67 to 79.99%, and 85.04 to 10.01% for sites a, b, and c, respectively. a flushing velocity of 0.15 m/s with no chlorination, shock chlorination of 3400 mg/l and flushing velocity of 0.15 m/s, and shock chlorination of 3400 mg/l and flushing velocity of 0.6 m/s treatment regiments were applied to all laterals collected to assess emitter flow rate recovery to the nominal flow rate published by the manufacturer. all laterals showed an increase in the number of emitters within 10% of the published nominal flow rates. case study the main idea in this research is to generate data for drip irrigation system by using analogue system that mean simulate the field work in an electrical circle work with dc voltage . field work layout the water source is al-zabar stream in khagan village in babylon governorate, 30:15:15 e, 44:40:30 n in the middle of iraq and the maximum pressure level is 16m head. water is provided by using a pump give a head of 20m with flow rate180 l/min). behind the pump there is a filter (plastic filter type) and a valve to regulate and control the main discharge and main pressure head in the main line. the main line is a plastic pipe with 25mm diameter and one meter in length. the main pipe is divided into two manifold plastic pipes each is 25mm in diameter and 2.5m long. from the manifold two laterals with valves at the head and end of each lateral and there is air relief at the ends of the laterals. the lateral is polyethylene pipe 16mm in diameter and 15m long. the spacing between two laterals is 1.25m; the ends of the laterals are looped together by a polyethylene pipe 16mm in diameter. the main pipe connected with the looped pipe by carrier pipe. the main pressure gage is connected downstream the pump and upstream the controlling and regulating valve on the main pipe. other pressure gages are connected at the head, middle, and the end of each lateral in the network. there are 13 gauges in total in the whole network. the traditional network is represented through the end valves enclosure while the proposed network is represented by opening the end valves. (figure 1) and (figure 2) shows the network at two cases, and the locations and numbers of the emitters and gages. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 419 analogue system analogue techniques are potentially useful for data processing and for providing elements in instrumentation and control systems. the principle of studying a system indirectly by reference to an analogue system may be applied in a number of different ways. the relation between a system and its analogue is basically a mathematical one in which the set of equations that describes the interactions between various system variables is identical to the set of equations describing the interaction between corresponding variables in the analogue. the earliest analogue devices were based on mechanical system, in which the analogue variables were the positions of the shafts. the movements of these shafts could be amplified or reduced (multiplied by constant) by the use of simple fixed gearing; two variables could be added or subtracted by means of differential gears; integration was achieved by a ball and wheel assembly. different problems were solved by adjusting the mechanical layout of the analogue system so as to satisfy the appropriate set of equations, but perhaps acceptable for a specialpurpose model of a particular system. it is also possible to build an analogue system based on hydraulic or pneumatic principles, and for some applications special-purpose analogue models of these kinds have proved to be useful [wilkings, 1970]. analogue components the components of electrical analogue in the case study are depicted (figure 3) where the analogue system consists of: 1. thermal wires (500 watts) to simulate the laterals where the power loss due to temperature in the thermal wires simulates the friction head losses in the laterals. 2. a power supply to simulate water supply. 3. a voltage regulator (1 volt) to simulate the valve in the main pipe used to regulate the discharge. 4. an ammeter to simulate the pressure gages. 5. resistors (1 kilo ohm) to simulate the emitters. 6. switches (on-off) at the ends of the lines of analogue to simulate the valves at the ends of the laterals (i.e. when switched off this state simulate traditional network and when switched on this state simulate looped network. 7. equation (1) simulates equation v=b (2) where: q: the discharge of emitter ( . a: a coefficient specific to each emitter, h: the pressure at the emitter (l), al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 420 x: an exponent depends on the flow regime, v= voltage in the resistor (volt), i= current in the resistor (amber), and b, y = constants the values of b and y may be found by any statistic program, and in this research, spss program has been used. component emitters from the field results found the emitters components for the three types of emitter that used in the research and (table 1) showed the components values for equation (1) analogue results the switches are on when the system is on the proposed network (figure 2), values of the constants in eq. (2) are: (b=10.774 and y=0.191), which are computed through using spss program. comparing eq.(1) below which is relative to the hydraulic performance of the emitter, with the eq. (2), which is relative to the electrical behavior in the analogue system, then the relative equation from the previous both equations is: example: for emitter type i with (x=0.539and a=6.429): v=10.774 when q=v as a value can be found the equation h=r (3) h=2. 61 (table 2) lists the relative constants in eq. (3) for the three types of emitters that have been used. analogue and field results the average results are used to summarize the average relative variation in proposed system to compare the analogue and field results as listed in (table 3). dissection the results from the field data and the results that generated by equation 3 that seen the variation of the discharges were at the range (7.36 to 8.44) that mean the relative error in discharge was small when use the analogue system and that variation was acceptable from the engineering approach . al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 421 conclusions from the results that generated the following conclusions are drawn from this study: 1the generated data near the field data with few errors. 2the generated data can be used in the studies for irrigation system. references al-misned, ahmed s., 2000"effect of energy loss due to emitters on the design of trickle irrigation laterals", soil science king saud university, riyadh, saudi arabia. bralts, v. f., i. p. wu and m. gitlin, 1981 "manufacturing variation and drip irrigation uniformity", trans. asae 24(1): 113-119. jahad, u. a., (2010), hydraulic comparison of the performance of irrigation drippers in traditional with proposed looped network, unpublished m sc thesis, department of water resources, college of engineering, university of baghdad, iraq keller, j. and d. karmeli, 1975 "trickle irrigation design", ed and publ. by rain bird sprinkler manufacturing crop. , glendora, ca91740. keller, j. and r.d. bliesner, 1990" sprinkle and trickle irrigation", new york: van, 1990. krystal and k. zanker, 1974 "hydraulic and mechanical properties of drippers", in proc. of the 2nd int. drip irrigation congress. san diego, ca. madramootoo, c. a., 1981"the development of trickle irrigation system for banana (musa spp.) production in st. lucia", m. sc. thesis, college of agricultural engineering, university of mc gill, canada. mizyed, n and e.g. kruse, 1989 "emitter discharge evaluation of subsurface trickle irrigation systems", transactions of the asae, 32: 1223-1228. robert, a. schultheis, 2005" irrigation of vegetable and small fruit crops" natural resource engineering specialist, university of missouri extension. similarly, capra a. and b. scicolone, 1998 "water quality and distribution uniformity in drip/trickle irrigation systems", j. agric. eng. res., 70: 355-365. solomon, k., 1979 "manufacturing variation of trickle emitter", trans. asae 22(5): 10341038, 1043. vance leo, 2004" evaluation of the application uniformity of subsurface drip distribution systems ", m.sc. thesis, b.s, texas a&m university. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 422 table (1): values of and a for used emitter (jahad, 2010) type of flow regime r² x a type of emitter no. of emitter turbulent 0.86 0.539 6.429 orifice emitter i turbulent 0.83 0.462 7.216 adjustable mini bubbler flow dripper ii turbulent 0.89 0.601 5.256 adjustable flow dripper iii table 2: values of (r) and (p) in equation h=r analogue component type of emitter no. of emitter p r 0.354 2.61 orifice emitter i 0.4134 2.38 adjustable mini bubbler flow dripper ii 0.318 3.301 adjustable flow dripper iii al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 423 table 3: average relative variation comparison for analogue and field field r.qv.% analogue r.v.v.% state type (iii) type (ii) type (i) 7.60 8.44 7.36 8.17 proposed where: r.v.v: relative variation of voltage r.v.q: relative variation of emitter discharge that calculated by equation 3 al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 424 4.1 4.2 4.3 4.14 4.15 4.16 4.27 4.28 4.29 4.40 4.41 4.42 4.50 4.51 4.52 9.75m 0.75m 1.25m 2.5m 3.1 3.2 3.3 3.14 3.15 3.16 3.27 3.28 3.29 3.40 3.41 3.42 3.50 3.51 3.52 2.1 2.2 2.3 2.14 2.15 2.16 2.27 2.28 2.29 2.40 2.41 2.42 2.50 2.51 2.52 1.1 1.2 1.3 1.14 1.15 1.16 1.27 1.28 1.29 1.40 1.41 1.42 1.50 1.51 1.52 fig. (1): system layout. pump basin carrier valve looped manifold pressure gauge al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 425 fig (2): the field system. fig. (3): the schematic analogue system al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 204 four wave mixing nonlinearity effect in wavelength division multiplexing radio over fiber system by assistance lecturer mohammed ali k. n abstract the integration of wireless and optical networks is a potential solution for the increasing capacity and mobility as well as decreasing costs in the access networks. optical networks are fast, robust and error free, however, there are nonlinearity obstacles preventing them from being perfect media. the performance of wavelength division multiplexing (wdm) in radio over fiber (rof) systems is found to be strongly influenced by nonlinearity characteristics in side the fiber. the effect of four wave mixing (fwm) as one of the influential factors in the wdm for rof has been studied here using optisystem and matlab. from the results obtained, it is found that the fwm effects have become significant at high optical power levels and have become even more significant when the capacity of the optical transmission line is increased, which has been done by either increasing the channel bit rate, and decreasing the channel spacing, or by the combination of both process. it is found that when the channel spacing is 0.1 nm, 0.2 nm and 0.5 nm the fwm power becomes about -59dbm to -79dbm respectively. this result confirms that the fiber nonlinearities play decisive role in the wdm for rof system. the simulation results obtained here are in reasonable agreement as compared with other numerical simulation results obtained, elsewhere, using different simulation tools. 1. introduction in the past, dating back to the beginning of the human civilization, communication was done through signals, voice or primitive forms of writing and gradually developed to use signaling lamps, flags, and other semaphore tools. as time passed by, the need for communication through distances, to pass information from one place to another, became necessary and the invention of telegraphy brought the world in to the electrical-communication[guo,kao andching2009]. the major revolution that affected the world however was the invention of the telephone in 1876. this event has drastically transformed the development of communication technology. today’s long distance communication has the ability to transmit and receive a large amount of information in a short period of time. since the development of the al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 205 first-generation of optical fiber communication systems in the early 80’s [rober 2004], the optical fiber communication technology has developed fast to achieve larger transmission capacity and longer transmission distance, to satisfy the increased demand of computer network. since the demand on the increasing system and network capacity is expected, more bandwidth is needed because of the high data rates application, such as video conference and real-time image transmission, and also to achieve affordable communication for everyone, at anytime and place [hamed 2011]. the communication capabilities allow not only human to human communication and contact, but also human to machine and machine to machine interaction. the communication will allow our visual, audio, and touch sense, to be contacted as a virtual 3-d presence [govind 2001]. to keep up with the capacity increasing requirement, new devices and technologies with high bandwidth are greatly needed by using both electronic and optical technologies together to produce a new term radio over fiber (rof). the progress made so far has been impressive, where information rate at 1 terabits/s can be handled by a single fiber [yannis 2010]. rof technology entails the use of optical fiber links to distribute rf signals from a central location (headend) to remote antenna units (raus). in narrowband communication systems and wireless local area network (wlans), most of signal processing (including coding, multiplexing, rf generation, modulation, etc) are made in central stations (css) rather than in the base station (bs -s) [anthong 2005]. the signal between cs and bs is transmitted in the optical band via a rof network. this architecture makes design of bs-s quite simple. in the simplest case, the bs consists mainly from opticalto -electrical (o/e) and electrical-to -optical (e/o) converters, an antenna and some microwave circuitry (two amplifiers and a diplexer). the centralization of radio frequency (rf) signal processing functions enables equipment sharing, dynamic allocation of resources, and simplifies system operation and maintenance. these advantages could be translated into major system installation and operational savings, especially in wide-coverage broadband wireless communication systems, where a high density is necessary. the rapid development of the wireless communication networks has increased the need of the optical signal processing. the link lengths have grown to thousands of kilometers without need to convert optical signals back and forth to electric form, and the transmission speeds of terabits per second are feasible today [takuo and kazuro 2011]. this ever -growing demand for the high speed communication has forced to use higher bit rates as well as transmission powers. nonlinear effects on communication have become significant at high optical power levels and have become even more important since the development of erbium-doped fiber amplifier (efda) and dwdm systems. by increasing the capacity of the optical transmission line, which can be done by increasing channel bit rate, decreasing channel spacing or the combination of both, the fiber nonlinearities come to play even more decisive role [antti 2003]. the origin of the nonlinearities is the refractive index of the optical fiber, which is varies with the intensity of the optical signal. this intensity-dependent component of the refractive index includes several nonlinear effects, such as spm, xpm, fwm, srs, and sbs, and becomes significant when high powers are used. although the individual power in each channel may be below the level needed to produce nonlinearities, the total power summed over all channels can quickly become significant. the combination of high total optical power and large number of channels at closely spaced wavelengths is a source for many kinds of nonlinear interactions [marcus 1991]. form the above mentioned reasons, this study is aimed to gain insight into nonlinear effect caused specifically by fwm in the wdm for rof system and measure the coefficient behind these nonlinear effects. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 206 2. simulation modeling this section highlights the techniques and methods employed to study the nonlinear effects of fwm in wdm for rof as well as to analyze the modeling results obtained. details of the methods will be given in the proceeding sections. using optisystem software, two types of simulation models have been developed to study fwm effects. the two models are with external modulated signal and without external modulated signal as shown in the figure 1 and 2, respectively. the frequency of the phase modulator drive signal was kept at 2.4 ghz. the phase modulator has been used to sweep the optical frequency, it was necessary to first integrate the drive signal [caiqin andxiupu 2006]. the simulation models were modified according to the related parameters or components for different types of simulation process as given below:  effect of channel spacing.  effect of different power level of the signals sources  effect of increase dispersion of the fiber optic  effect of increase effective area of the fiber optic a. simulation of the four wave mixing effect each component in both simulation models, shown in figures 1 and 2, has its own role, to play in the process. the continues wave (cw) generator is a generator of continuous-wave millimeter-wave optical signals. the spectral line-width of the generated millimeter-wave signals is 2 khz. the power of the measured cw millimeter-wave signals is almost in proportion to the power multiplication of the two input optical signals. the mach-zehnder modulator, is a modulator, which has two inputs, one for the laser diode and the other for the data from the channels. the wdm multiplexer is a method of transmitting data from different sources over the same fiber optic link at the same time whereby each data channel is carried on its own unique wavelength. the optical fiber is used in the simulation is a single mode fiber (smf28), where the dispersive and nonlinear effects are taken into account by a direct numerical integration of the modified nonlinear schrödinger (nls) equation. besides the above components there are three types of components, which used for visualizing purposes: i. optical power meter visualizer ii. optical spectrum analysis iii. wdm analyzer b. simulation of fwm for higher number of channels sources in the simulation model were increased to three or four channels. figures 3 and 4 show the sources increased in the new simulation model based on direct modulation [ooi 2007]. c. effect of different power level of the signals sources the main requirement from a wireless communication system is that the transmitted electro magnetic (em) wave must reach the receiver with ample power to allow the receiver to distinguish the wave from the background noise. another common property used to describe signal strength is the s/n ratio. the s/n ratio does not describe the absolute power in the signal, but instead describes the power of the signal in al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 207 comparison to the power of the background noise. the higher the s/n ratio, the better or more powerful the signal. since the s/n ratio accounts for the level of background noise, it is a very valuable and widely used indicator of signal strength. in the simulation process, the power at the simulation model sources was varied from 20 dbm to -10 dbm with step of -10 dbm to in order try different simulations. d. effect of increase dispersion of the fiber optic wavelength dispersion, is a signal dispersion, which occurrs primarily in single mode fiber. a significant amount of the light launched into the fiber is leaked into the cladding. this leaked amount is wavelength dependent and also influences the speed of propagation. high volume communication lines have carefully timed spacings between individual signals. fortunately, wavelength dispersion can be minimized by careful designation of fiber refractive index. the dispersion parameter of the fiber optic in the simulation model was varied from 1 ps/nm/km to 16.75 ps/nm/km. this has been done in order to compare the results with different dispersion parameters and the power level of sources set at 0 dbm. e. effect of increase effective area of the fiber optic the effective area (aeff) of the single-mode fiber is an important measurement parameter. it is the area of the cross section of the beam arrived into the fiber. the effective area evaluation requires the measurement of the field distribution in the fundamental mode. the effective area parameter of the fiber optic in the simulation model has been changed from 64 μm 2 to 76.5 μm 2 , in order to compare the results with different effective area parameters as the power level of sources set at 0 dbm.. 3. modelling the effect of fwm matlab program is used to develop the analytical model of the effect of fwm in wdm for rof. the modeling is meant to study the nonlinear effects due to the fwm in wdm for rof when the light passing through the medium. figure 4 shows the steps that will be followed in the modeling process. the total polarization p is nonlinear with respect to the electric field e, however, it can be written as: (1) where is the vacuum permittivity and χ¹ (ј=1,2,……..)is јth order susceptibility. when light propagates in a transparent medium, its electric field causes some amount of polarization in the medium. while at low light intensities the polarization is linear with the electric field, nonlinear contributions become important at high optical intensities, so the polarization equation consists linear terms as well as nonlinear terms. the first order susceptibility χ(1) represents the linear term, and nonlinearities can have strong effects in fibers at the third order susceptibility χ(3). so, only the nonlinear effects in the optical fibers, which originate from the third-order susceptibility χ(3), will be considered and the other terms will be neglected. the programming will start from the thirdorder susceptibility χ(3). thus the electric field of the signal can be written as [6]: (2) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 208 where β i s the propagation constant , and ω i s angular frequencies substituting equation 2 into equation 1, and if only the term of the third order susceptibility is taken into account, the nonlinear dielectric polarization (pnl(r,t))can written as [6]: (term 1) (term 2) + (term..3) (term…4) (term….5) (term…6) (term…7) (term..8) (3) the nonlinear susceptibility of the optical fiber generates new waves at the angular frequencies ± ω s ± ω t (r, s , t = 1, 2,…). term 1, in the above equation represents the effects of spm and xp terms 2, 4 and 5 can be neglected, due to lack of phase matching. the remaining terms can satisfy the phase matching condition. the power transferred due to the fwm to new frequencies after light has propagated distance l in the fiber can be estimated from equation 4.4 [6]: al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 209 (4) where is the effective index , is the effective area, , , are the input powers at , the factor depends on the number of channels affecting fwm. the efficiency of fwm and noise performance are analyzed ,taking into account the effects of difference channel spacing . equation 5 is presented to evaluate the efficiency of the fwm . (5) equation 6 is used to investigate the relationship between the efficiency and power of the fwm [6]. (6) where is effective length , which can be calculated by using equation (7) (7) where frequency ,d is the degeneracy factor , is third order considered as zero, thus ,their effects on fwm modeling are neglected. term 1 representing xpm &spm will be considered as of zero effect and will be neglected too. the four –wave mixing, require the phase matching to be efficient. essentially this is mean to ensure a proper phase relationship between the interacting waves fwm will be a peak at the phase matching spectrum. equation 4.8 satisfies the condition of phase matching =β(ω1 )+ β(ω2 ) (8) where is the propagation constant .if the phase matching condition is satisfied otherwise mismatching occurs. the model in this study will use only two wave lengths , therefore the phase matching condition will be ) in order to satisfy the phase matching. 4. calculation results and analysis in this section presents and discusses the results obtained from the simulation model by using optisystem as numerical simulation and matlab as analytical simulation. the numerical simulation is simulated accordingly as mentioned in the previous sections, with and without external modulated laser. a. simulation of the four wave mixing effect in the fwm simulation model layout, two types of visualiser tools have been used. the optical spectrum analyzer and the wdm analyzer were fixed after mux and at the end of the fiber optic. the results obtained after the multiplexer are same as the input power level shown before the nonlinear effect. the al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 210 nonlinear effect occurs only during the propagation of signals through the fiber. the optical spectrum analyzer has been used to show the waveform whereby the wdm analyzer has been used to display signal power (dbm), noise power (dbm) and osnr (db). b. simulation results without the external modulated signal in this simulation two cw lasers were used as signals sources, the frequencies were set at 1550 and 1550.1 nm, where as the power was set at 0 dbm. the linewidth has been set at 0, due to the interest in measuring only the total power of the sideband frequencies, where the shape of the spectrum is not required. the input signals have propagated through 25 km of nonlinear fiber. figure 5 shows the signal at the input channel when the channel spacing is set at 0.1 nm. the result obtained from the simulation is depicted in figure 6. from this figure, the fwm effect is obviousl because the simulation without external modulated laser is simpler compared to the simulation model with external modulated laser. the interfering wavelengths generated around the original two wavelength systems are 1549.9 nm and 1550.2 nm, thereby the power of the each fwm sideband is approximately -59 dbm figure 7 shows the signal at the input channel when the channel spacing is set at 0.2 nm. when the channel spacing is increased to 0.2 nm, the result obtained from the simulation is depicted in figure 8. the interfering wavelengths generated around the original two wavelength system are 1549.8 nm and 1550.4 nm, thereby the power of the each fwm sideband is approximately -61 dbm. similarly, figures 9 shows the signal at the input channel when the channel spacing is increased to 0.5 nm. figure 10 shows the interfering wavelengths generated around the original two wavelength system of 1549.5 nm and 1551 nm; thereby the power of each fwm sideband is approximately -71 dbm. therefore, as the spacing between channels is increased the effect of the fwm is decreased. figure 11 optical spectrum at the output of the fiber when input power is set at 20 dbm. the result obtained from the simulation when the input source power is set at 10 dbm is depicted in figure 12. the result obtained from the simulation when the input source power is set at -10 dbm is depicted in figure 13. from the result s, given it is clear that when the power level is increased to 20 dbm the effect of the fwm becomes very severe as shown in the figure 11. as the power level of the signal sources is decreased to 10 dbm the fwm becomes less effective, as shown in the figure 13, therefore, the fwm becomes significantly effective at high optical power levels. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 211 the effect of dispersion parameter of fiber optic was changed from 1.0 ps/nm/km to16.75 ps/nm/km, at input power of 0 dbm. the results were taken at the end of the fiber optic. simulation results at dispersion of 16.75 ps/nm/km at input power of 0 dbm is shown in figures 14. the results obtained at the end of the fiber when the power level is set at 0 dbm and the dispersion is set at 16.75 ps/nm/km as shown in figure 14, was compared with the result obtained at the same power level and dispersion of 1 ps/nm/km as shown in figure 8, these result show that the fwm products were reduced when the dispersion parameter is increased. it is important to mention that the dispersion parameter can not be set at too high value because it does bring limitation in bandwidth in the wdm model. 4.1 simulation results with the external modulated signal in this simulation two cw lasers were used as signals sources, the frequencies were set at 1550 and 1550.1 nm, where as the power was set at 0 dbm, due to the interest in measuring only the total power of the sideband frequencies, where the shape of the spectrum is not required. the input signals have propagated through 25 km of nonlinear fiber. 4.1.1 effect of channel spacing variation figure 15 shows the signal at the input channel when the channel spacing is set at 0.1 nm. the result obtained from the simulation is depicted in figure 16. the fwm effect is not quite obvious because the external modulation produce sideband. from figures 18, the fwm effect is quite obvious when the channel spacing is increased to 0.2. the power of the fwm sideband is approximately -72 dbm figure 19 shows the signal at the input channel when the channel spacing is set at 0.5 nm. also in figure 20, the fwm effect is quite obvious when the channel spacing is increased to 0.5 nm. the power of the fwm sideband is approximately -87 dbm therefore, as the spacing between channels is increased the effect of the fwm is decreased. 4.1.2 effect of different power level of the signals sources in the following process, the power level of the input sources was varied from 20 dbm to -10 dbm with step -10 dbm while other parameters such as the dispersion and the effective area were kept unchanged. the result obtained from the simulation when the input source power is set at 20 dbm is depicted in figure 21. the result obtained from the simulation when the input source power is set at 0 dbm is depicted in figure 22. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 212 the result obtained from the simulation when the input source power is set at -10 dbm is depicted in figure 23. from the result s, given it is clear that when the power level is increased to 20 dbm the effect of the fwm becomes very severe as shown in the figure 21. as the power level of the signal sources is decreased to 10 dbm the fwm becomes less effective, as shown in the figure 23, therefore, the fwm becomes significantly effective at high optical power levels. the new generated mixing products have high possibilities of falling directly on the original signal, which produce crosstalk. 4.1.3 effect of increase dispersion of the fiber optic simulation results with the use of the external modulated laser at dispersion of 16.75 ps/nm/km at input power of 0 dbm is shown in figures 24. the results obtained at the end of the fiber when the power level is set at 0 dbm and the dispersion is set at 16.75 ps/nm/km as shown in figures from 24. were compared with the result obtained at the same power level and dispersion of 1 ps/nm/km as shown in figure 16, these result show that the fwm products were reduced when the dispersion parameter is increased. it is important to mention that the dispersion parameter can not be set at too high value because it does bring limitation in bandwidth in the wdm model. 4.1.4 effect of increase effective area of the fiber optic simulation results with the use of the external modulated laser at effective area of 76.5 μm 2 at input power of 0 dbm are shown in figure 25. results obtained at the end of fiber where the power level is set at 0 dbm, and the effective area is increased to 76.5μm 2 is shown in figure 25 is compared with figure 16 which the effective area is set at 64 μm 2 . it is found that the increasing of the effective area can reduce the fwm effect. 4.2 simulation of four wave mixing for higher number of channels this section presents the simulation results as the number of channels is increased to four in the simulation model, with or without the use of external modulated laser. 4.2.1 simulation results for four signal source without external modulated signal the simulation results for four channels, without use of external modulated laser, figure 26 shows input signal when number of channels is increased to four and the channel spacing is set at 0.1 nm. the result obtained from the simulation when the number of channel is increased is depicted in figure 27. the number of fwm also is increased. the result obtained from the simulation when the number of channel is increased and the channel spacing is set at 0.5 nm is depicted in figure 28. the number of fwm also is increased. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 213 4.2.2 simulation results for four signal source with external modulated signal the simulation results for four channels, when using external modulated laser, at different channel spacing. figure 29 shows input signal when number of channels is increased to four and the channel spacing is set at 0.1 nm. the result obtained from the simulation when the number of channel is increased and the channel spacing is set at 0.1 nm is depicted in figure 30. the number of fwm is also increased. the result obtained from the simulation when the number of channel is increased and the channel spacing is set at 0.5 nm is depicted in figure 31. the number of fwm is also increased but with less effect. 5. discussions based on the results presented , the fwm effects increase as the number of channels is increased. the number of spurious signals due to fwm increase geometrically and given by: (8) where n is the number of channels and m is the number of the newly generated sidebands. the new generated mixing products have high possibilities fall directly on the original signal , this could produce crosstalk. therefore, as the spacing between channels is reduced or remained equal the effect of the crosstalk is found to become greater. when the spacing between the channels is unequal, showed that the mixing products have low power level and highly possible not to falls on the original signal, which makes them easy to be filtered, and in turn improve the system performance. results obtained at the end of fiber where the power level is set at 0 dbm, and the effective area is increased to 76.5μm 2 are shown in figures 14. it is found that the osnr obtained is better than before increasing the effective area as shown in figure 8. as general, the increase of the effective area can reduce the fwm effect and give higher osnr value compared to the simulation result obtained with the same power level. the effective area refers to the equivalent area of the fiber in which the optical power is transmitted. in the case of single mode fiber, this is roughly proportional to the core area. fiber with a large effective area offers reduced optical power density, which raises the power threshold for the fwm penalties. in addition, the effective area parameter and the dispersion parameter can be used to calculate the fwm efficiency as follows: (aeff x d x ∆λ 2 ) (9) where η is the fwm efficiency, n2 is the nonlinear index coefficient, aeff is the effective area, d is the dispersion and δλ is the spectral width. 5.1 analytical modelling matlab based program has been developed in order to design analytical model which assists to predict the expected fwm power in different channel spacing. the designed model can give the expectation value of the fwm power in different input signal power level. the analytical results have been compared to the results obtained from the numerical simulation, as shown in figures 32 and 33. these results show that when power per channel is increased the spurious power increase, too. the power of the fwm produced is found to be inversely proportional to the square of the channel spacing, when all al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 214 channels have the same input power. furthermore, the fwm effects increase exponentially as the level of the optical power from the signal sources is increased, as shown in the figure 32 based on results presented, it is clear that when the channel spacing is smaller the fwm effect becomes more significant due to the phase matching, as shown in figure 33. 5.2 four wave mixing reduction one way to combat the fwm process is to use unequal channel spacing, so that the mixing products do not coincide with signal frequency, and to use low input power, or high effective area. fiber dispersion management is a very effective way, helpful not for fwm but also is the case of other nonlinear phenomena, that degrade transmission performance in the fiber, also fwm can be mitigated by increasing the effective area of the fiber [13]. 5.2.1 effect of unequal channels figure 34 shows input signal when the channel spacing is unequal. when the spacing between the channels is unequal, showed that the mixing products have low power level and highly possible not to falls on the original signal, which makes them easy to be filtered, and in turn improve the system performance. as shown figure 35. 5.2.2 effect of increase effective area of the fiber optic the effective area parameter of fiber optic has been changed from 64 μm 2 to 76.5 μm 2 at the power level set at 0 dbm. the results were taken at the end of the fiber optic. simulation results at effective area of 76.5 μm 2 at input power of 0 dbm are shown in figures 36. results obtained at the end of fiber where the power level is set at 0 dbm, and the effective area is increased to 76.5 μm 2 as shown in figure 36. it is found that the increasing of the effective area can reduce the fwm effect. 6. conclusions future wireless systems it will be targeting towards providing broadband access and personal area multimedia services to large number of subscribers. radio over fiber (rof) network accompanied with wavelength division multiplexing (wdm) can provide a simple topology, easier network management, and an increased capacity by allocating different wavelengths to individual remote nodes. the performance of wdm networks is strongly influenced by nonlinearity characteristic inside the fiber. therefore the nonlinearity effects of fiber optics pose additional limitation in wdm systems. it is well known that fwm in wdm for rof signals are mostly generated by non-degenerate fwm process regardless of the number of input signals. in this study only two and four input signals were launched into the optical fiber. the fwm effect has been investigated analytically and numerically simulated. simple equations to determine the spectral linewidth, the fwm power due to channel spacing and the power of the fwm components due to the input power have been deduced. the numerical simulation results obtained have shown the spectral characteristics of the fwm in wdm for rof where the effects of fwm are pronounced with decreased channel spacing of wavelengths or at high signal power levels. the numerical simulation model results and the analytical model results were compared. the numerical simulated results clearly demonstrate that the degradation due to fwm can be minimized by ensuring that al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 215 the phase matching does not occur. this has been achieved by increasing the channel separation and supplying low signal power level. the high effective area is also found to the decrease fwm effect. it is noticed that the fwm also causes inter-channel cross talk for equally spaced wdm channels. thus, fwm can be mitigated using unequal channel spacing. it could be concluded that results obtained from this study will provide useful information for identifying the fundamental limit of the capacity of the wdm systems. references 1. guo, y., kao, c. k. and chiang, k. s. “nonlinear photonics: nonlinearities in optics, optoelectronics and fiber communications.” springer -verlag, 2009. berlin, germany. 2. robert, c. e. “ optical networking a beginer’s guide” mcgraw-hill/osborne 2004 3. hamed al-raweshidy, “radio over fiber technologies for mobile communications networks” , artech house , 2011. 4. govind p.agrawal, “fiber-optic communication system” mcgraw-hill december 2001. 5. yannis, l. g. “new optical microwave up-conversion solution in radio over fiber network” journal of lightwave technology, 24 (3) (2010) 1277-1282. 6. ajung kim, young hun joo, and yungsoo kim, “60ghz wireless communication systems with radioover -fiber links for indoor wireless lans” journal of lightwave technology, 20, (4), ( 2004) 517 -521. 7. anthong no’oma, “radio over fiber technology for broadband wireless communication systems” master thesis, eindhoven university of technology, 2005. 8. takuo tanemura and kazuro kikuchi, “ unified analysis of modulational instability induced by cross-phase modulation in optical fiber s” journal of lightwave technology , 20 (12) (2011) 25022513. 9. antti lamminpää, “measurement of nonlinearity of optical fiber.” master thesis, helsinki university of technology, 2003. 10. d. marcuse, “effect of fiber nonlinearity on long-distance transmission”, journal of lightwave technology, 9 (1) (1991) 121-128. 11. caiqin wu and xiupu zhang, “impact of nonlinear distortion in radio over fiber systems with single-sideband and tandem single –sideband subcarrier modulations ” journal of lightwave technology , 24 (5) (2006) 2076 – 2090. 12. ooi sock, “four wave mixing nonlinearity effect in wavelength division multiplexing system for radio over fiber.” bachelor thesis, university technology malaysia, 2007. 13. vrizlynn l. l. thing, p. shum, and m. k. rao, “bandwidth-efficient wdm channel allocation for four-wave mixing-effect minimization”, transactions on communications, 52 (12) (2004) 2184-2089. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 216 figure 1 simulation model with external modulated signal figure 2 simulation model without external modulated signal figure 3 simulation model with three channels al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 217 figure 4 simulation model with four channels figure 5 optical spectrum at the input of the fiber when channel spacing is set at 0.1 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 218 figure 6 optical spectrum at the output of the fiber when channel spacing is set at 0.1 nm figure 7 optical spectrum at the input of the fiber when channel spacing is set at 0.2 nm figure 8 optical spectrum at the output of the fiber when channel spacing is set at 0.2 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 219 figure 9 optical spectrum at the input of the fiber when channel spacing is set at 0.5 nm figure 10 optical spectrum at the output of the fiber when channel spacing is set at 0.5 nm figure 11 optical spectrum at the output of the fiber when input power is set at 20 dbm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 220 figures 12 optical spectrum at the output of the fiber when input power is set at 10 dbm figures 13 optical spectrum at the output of the fiber when input power is set at -10 dbm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 221 figure 14 optical spectrum at the output of the optical when the dispersion of fiber optic is set at 16.75 ps/nm/km figure 15 optical spectrum at the input of the fiber when the channel spacing is set at 0.1 nm figure.16 optical spectrum at the output of the fiber when the channel spacing is set at 0.1 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 figure 17 shows the signal at the input channel when the channel spacing is set at 0.2 nm. figure 18 optical spectrum at the output of the fiber when the channel spacing is set at 0.2 nm figure 19 optical spectrum at the input of the fiber when the channel spacing is set at 0.5 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 223 figure 20 optical spectrum at the output of the fiber when the channel spacing is set at 0.5 nm figure 21 optical spectrum at the output of the fiber when input power is set at 20 dbm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 224 figure 22 optical spectrum at the output of the fiber when input power is set at 10 dbm figure 23 optical spectrum at the output of the fiber when input power is set at -10 dbm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 225 figure 24 optical spectrum at the output of the fiber when input power is set at 0 dbm figure 25 optical spectrum at the output of the fiber when the effective area of the fiber optic is set at 76.5 μm 2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 226 figure 26 four optical spectrum at the intput of the fiber when the channel spacing is set at 0.1 nm figure 27 four output optical spectrum channels when the channel spacing is set at 0.1 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 227 figure 28 four output optical spectrum channels when the channel spacing is set at 0.5 nm figure 29 four input optical spectrum channels when the channel spacing is set at 0.1 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 228 figure 30 four output optical spectrum channels when the channel spacing is set at 0.1 nm figure 31 four output optical spectrum channels when the channel spacing is set at 0.5 nm al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 229 figure 32 power per channel vs. fwm power figure 33 channel spacing versus fwm power al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 230 figure 34 optical spectrum at the input of the fiber when the channel spacing is unequal figure 35 optical spectrum at the output of the fiber with unequal channel spacing al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 231 figure 36 optical spectrum at the output of the fiber when the effective area of the fiber optic is set at 76.5 μm 2 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 137 application of response surface methodology for determining hole diameter model in edm based micro holes cutting process received 2 february 2014 accepted 24 march 2014 abstract micro-edm is one of an important process in machining holes which is used in wide applications to fabricate medical devices and small dies.20 samples were run by using cnc edm machine was used for machining of conducting materials such as copper alloy workpieces for tap water dielectric by supplied dc current values (4, 6 and 10a), gap distance (0.3, 0.4 and 0.5mm) and machining time (5, 7 and 10min). voltage of (70v) was used to cut 0.7mm thickness of copper (cu) alloy workpieces to obtain the micro holes (400, 300, 210, 200, 120, 100, 85, 75, 70) μm. the present work demonstrates the optimization process of hole diameter producing using electrical discharge machining (edm) by rsm (response surface methodology). the current, gap distance and machining time were the control parameters of edm. rsm method was used to design the experiment using a second–order response surface. the process has been successfully modeled using rsm and model adequacy checking is also carried out using minitab software. finally, an attempt has been made to estimate the optimum machining conditions to produce the best possible responses within the experimental constraints. keywords: electrical discharge machining (edm), response surface methodology (rsm). لحساب نموذج قطر الثقب في عملية قطع الثقوب الدقيقة المعتمدة تطبيق طريقةاستجابة السطح على التشغيل بالتفريغ الكهربائي د. شكري حميد غضيب د. ليث عبداهلل محمد قسم هندسة االنتاج والمعادن قسم هندسة االنتاج والمعادن الجامعة التكنولوجية/ بغداد الجامعة التكنولوجية/ بغداد dr. laith a. mohammed metallurgy & production engineering department, university of technology/ baghdad email: dr.laith@uotechnology.edu.iq dr. shukry h. aghdeab metallurgy & production engineering department, university of technology/ baghdad email:shukryhammed@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 138 الخالصة: بالشرارة الكهربائية الدقيق هو احد الطرق المهمة لتشغيل الثقوب وله تطبيقات واسعة في تصنيع األجهزة الطبية والقوالب التشغيل في محلول عازل من ماء الحنفية مواد موصلة من سبيكة النحاس ل cnc-edmنموذج باستخدام ماكنة 02تم قطع الصغيرة. دقيقة(. الفولتية 02و 7 و 0ملم( وزمن تشغيل ) 2.0و 2.4, 2.0أمبير(، مسافة الفراغ ) 02و 6, 4بتسليط قيم تيار مستمر ) ,200 ,210 ,300 ,400)باألقطار التالية للحصول على ثقوب ميكرويةللنماذج وذلك ملم 2.7فولت لقطع سمك 72 هي المستخدمة 120, 100, 85, 75, 70) μm. التيار، مسافة تم اعتماد كل من هذا العمل يثبت مثالية عملية قطر الثقب بالتشغيل بالتفريغ الكهربائي بطريقة استجابة السطح. تجربة منميم طريقة استجابة السطح لتصتم استخدام على التشغيل بالتفريغ الكهربائي. للسيطرة كعوامل رئيسيةالفجوة وزمن التشغيل تم فحص . minitab برنامج وباستخدامباستخدام طريقة استجابة السطح نجحت عملية النمذجة المرتبة الثانية الستجابة السطح. أفضل استجابة ممكنة خالل التجربة. لتحديد ظروف التشغيل المثلى إلنتاجالنموذج المصمم introduction electrical discharge machining (edm) is one of the most widely used non-conventional machining processes in industry. edm is based on the principle of removing material by means of repeated electrical discharges between the tool termed as electrode and the workpiece in the presence of a dielectric fluid (sang, 2005). edm uses thermal energy to achieve a high precision metal removal process from accurately controlled electrical discharge, the electrode is moved towards the workpiece until the gap is small enough so that the impressed voltage is great enough to ionize the dielectric (hofy, 2007). the basic principle in edm is the conversion of electrical energy into thermal energy through a series of discrete electrical discharges occurring between the electrode and workpiece immersed in the dielectric fluid. the insulating effect of the dielectric is important in avoiding electrolysis of the electrodes during the edm process. spark is initiated at the point of smallest inter-electrode gap by a high voltage, overcoming the dielectric breakdown strength of the small gap. at this stage, erosion of both the electrodes takes place, after each discharge, the capacitor is recharged from the dc source through a resistor and the spark that follows is transferred to the next narrowest gap. the cumulative effect of a succession of sparks spreads over the entire workpiece surface lead to its erosion to a shape which is approximately complementary to that of the tool. the dielectric serves to concentrate the discharge energy into a channel of very small cross-sectional area. it also cools the two electrodes and flushes away the products of machining from the gap. a servo system is employed to ensure that the electrode moves at a proper rate to maintain the right spark gap, and to retract the electrode, if shortcircuiting occurs (shitij, 2008). on switching on the power supply, electric field is set-up in the gap between the electrodes. the electric field reaches maximum value at the point where the gap between the electrodes is smallest. spark location is determined by the gap distance and the gap conditions. in the presence of electrically conductive particles in the gap, thin particle bridges are formed. when the strength of the electric field exceeds the dielectric strength of the medium, electric breakdown of the medium takes place. ionization of the particle bridges takes place and a plasma channel is formed in the gap between al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 139 the electrodes. during the discharge phase, a high current flow through the plasma channel and produces high temperature on the electrode surfaces. this creates very high pressure inside the plasma channel creating a shock wave distribution within the dielectric. the plasma channel keeps continuously expanding and with it the temperature and current density within the channel decreases. plasma channel diameter stabilizes when a thermal equilibrium is established between the heat generated and the heat lost to evaporation electrodes and the dielectric. this enlarged channel is still under high pressure due to evaporation of the liquid dielectric and material from the electrodes. the evaporated material forms a gas bubble surrounding the plasma channel. during this phase, high energy electrons strike the workpiece and the positively charged ions strike the tool (for negative tool polarity). due to low response time of electrons, smaller pulses show higher material removal from the anode whereas, longer pulses show higher material removal from the cathode. the plasma channel deionizes when power to the electrodes is switched off. the gas bubble collapses and material is ejected out from the surface of the electrodes in the form of vapors and liquid globules. the evaporated electrode material solidifies quickly when it comes in contact with the cold dielectric medium and forms solid debris particles which are flushed away from the discharge gap. some of the particles stay in the gap and help in forming the particle bridges for the next discharge cycle. power is switched on again for the next cycle after sufficient de-ionization of dielectric has occurred (sourabh, 2008). as one of non-contact processing technology, micro-edm has very unique technology advantages and wide application prospects in the field of micro-fabrication. in practical applications, micro-edm has some problems, such as low efficiency and poor stability. for example, during electrode anti-copy process, it is often found that the discharge is discontinuous, resulting in low efficiency. at present, it lacks deep theoretical and applicant research in the respect of accurate recognition on gap state, which fails to provide the stable control of micro-edm with enough guidance (chi, 2011). micro-edm is a material removal process employing discharges between a workpiece and a micro scale electrode that are submerged in dielectric fluid. discharges occur when the electric field between the electrode and workpiece exceeds a critical value and the dielectric breaks down. either increasing the electric potential or reducing the separation distance between the electrode and workpiece may cause the field to exceed the critical value. charging and discharging the capacitor in a rc circuit governs the potential difference, while electronics control the separation distance by monitoring feed rate and short circuits. energy from each discharge melts a microscopic amount of material, which is subsequently washed away after the voltage drops and the discharge collapses (chris, 2005). (lakshmanan, 2013) study the optimization process for edm parameters using response surface methodology. the objective of this work is to study the influence of machining parameters of edm on micro hole cutting of copper alloy workpieces using, stainless steel electrode and dielectric solution (tap water), using dc current and low voltage (70v) to cut (0.7mm) thickness of copper alloy workpieces in order to obtain the micro holes. the second order mathematical model in terms of machining parameters is developed for hole diameter prediction using response surface methodology (rsm) on the basis of experimental results. experimentation and measurement of response the experiments include cutting 20workpieces of copper alloy with thickness (0.7)mm using stainless steel electrode with different current to each electrode (4, 6 and 10)a, the gap between the al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 140 electrode and the workpiece are (0.3, 0.4 and 0.5) mm. the fixed machining conditions were summarized in table (1, 2 and 3). the edm machine was attached with a power supply current pulses during discharging. the polarity of tool-electrode was negative (-) and the polarity of workpiece was positive (+). throughout the experiments, the dielectric fluid has been the tap water which can transport the high spark current between the tool-electrode and workpiece. the edm machine used in this work is shown in figure (1). all the experiments have been conducted on a cncedm machine (znc 435l), located at the machine tool unit, center of training & workshops in the university of technology, baghdad. the design of experiments technique is a very powerful tool, which permits to carry out the modeling and analysis of the influence of process variables on the response variables (box, 1987). improving the produced hole diameter is still challenging problem that restrict the expanded application of the technology. semi-empirical models of hole diameter for various workpiece and tool electrode combinations have been presented by various researchers. the influence of current, gap distance and machining time, over the hole diameter on copper alloy workpieces have been studied. the optimum processing parameters are very much essential to produce precise hole diameters, since these materials, which are processed by edm are costly and the process is expensive too. as the number of variables is 3, a total of 20 experiments were planned for this investigation, shown in table 1. experiments were carried out using cnc edm. table 2 shows the specification of edm machine. this work included an experimental work for electrical discharge machining (edm) to produce micro holes with different diameters (400, 300, 210, 200, 120, 100, 85, 75, 70) μm. the parameter hole diameter is selected as response variable. the machining parameters and their levels are shown in table 3. methodology response surface methodology (rsm) investigates the interaction between several illustrative variables and one or more response variables (box, 1987).the most important purpose of rsm is to use a series of designed experiments to attain an optimal response. a second-degree polynomial model is use in rsm. these models are only an approximation, but used because such a model is easy to estimate and apply, even when little is known about the process. the process of rsm includes designing of a series of experiments for sufficient and reliable measurement of the response and developing a mathematical model of the second order response surface with the best fittings. obtaining the optimal set of experimental parameters, thus produce a maximum or minimum value of the response. the minitab software was used to analyze the data (minitab, 2003). result and discussions using the experimental results for hole diameter as shown in table4, response surface model is developed for the adequacy of the model is then performed in the subsequent step. the f ratio is calculated for 95% level of confidence. the final response equation for hole diameter is given by second order model as (1): al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 141 hole diameter = 129.439 – (93.998* a ) + (23.230* b ) + (45.089* c ) + (86.997 a 2 ) (32.037 * b 2 ) + (1.891* c 2 ) (28.376 *a*b) – (10.173* a*c ) + (19.628 * b*c ) …………………………(1) where: a: current, b: gap distance and c: machining time. when (r 2 ) approaches unity, the better the response model fits the actual data. for the proposed model the value of coefficient of determination (r 2 ) is found to be 98.97%and adjusted r 2 statistic (r 2 adj) is 98.04%. this shows that the model for hole diameter can be regard as significant for fitting and predicting the experimental results. table 4 shows the values of ‘p’ for each term on the performance of hole diameter, the value of ‘p’ less than 0.05 (i.e., α=0.05, or 95% confidence) indicates that the obtained models are statistically significant. the current, gap distance and machining time are found to be significant factors that affect the producing of specifying hole diameter along with the square effect of current, gap distance, and the interaction effect of (a*b) and (b*c). whereas the interaction effect of the input variables (a*c) and (c*c) are insignificant. the normal probability plot of residuals for hole diameter as shown in figure (2). it is expected that data from experiments form a normal distribution. it reveals that the residual fall on a straight line, implying that the errors are spread in a normal distribution. here a residual means difference in the observed value (obtained from the experiment) and the predicted value or fitted value. this is also, confirmed by the variations between the experimental results and model predicted values analyzed through residual graphs, and are presented in figure (3). the parametric analysis has been carried out to study the influences of the input process parameter current, gap distance and machining time on the process response, hole diameter during edm process. three-dimensional response surface plots are formed based on the quadratic model to evaluate the variation of response. the plots are shown in figures (4,5 and 6).these plots can also give further assessment of the correlation between the process parameters and response as follow: 1.hole diameter decreases with decreases in gap distance and machining time as shown in figure (4). 2. hole diameter decreases with increasing current and increases with increasing machining time as shown in figure (5). 3. hole diameter decreases with increasing current and increases with increasing gap distance up to max. value at 0.4 as shown in figure (6). confirmation test the optimization plot as shown in figure(7) provides the optimum values for all the input parameters using response optimizer. the optimum values are as follows: optimum current is 6a, optimum gap distance is0.5 mm, optimum machining time is 6.7191minto get hole diameter 150 μm. to validate the parametric values obtained, an experiment was conducted with the previous optimum values, which yielded the hole diameter of 149 μm. this confirms that the proposed model is proved to be good enough to predict the hole diameter in edm based micro holes cutting process. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 142 conclusions experimental investigation on electrical discharge machining of copper alloy is performed with a view to correlate the process parameters with the responses for produced hole diameter. the process has been successfully modeled using response surface methodology (rsm) and model adequacy checking is also carried out. the second-order response models have been validated. this study can help researchers and industries for developing a robust, reliable knowledge base and early prediction of hole diameter without experimenting with edm process for copper alloy. references [1]. box g.e.p., draper n.r.,1987, “empirical model – building and response surfaces”, john wiley & sons, new york. [2]. chi guanxin, geng xuesong, hu ing hi, 2011, gap state recognition research on micro-edm electrode nti-copy , school of mechatronics engineering arbin nstitute of technology arbin, china. [3]. hris j. morgan, et al, 2005, micro-machining and micro-grinding with tools fabricated by micro electro-discharge machining , nt. j. nano manufacturing, ol. , no. , s . [4]. ofy .g.,2007, “ dvanced machining processes, chapter 5, pp. 115-140, by mcgraw-hill, production engineering department, alexandria university, egypt. [5]. lakshmanan s. and et al,2013, “optimi ation of edm parameters using rsm for en31 tool steel machining”, nt. j. of eng. sci. & nnovative technology, ol.2, no.5. [6]. minitab 14,2003, “minitab ser manual”, state ollege, s . [7].sang s. k.,2005, “determination of wall thickness and height limits when cutting various materials with wire electro discharge machining process”, thesis submitted to faculty of brigham young university. [8]. shitij, s.,2008,“effect of powder mixed dielectric on material removal rate, tool wear rate and surface properties in electric discharge machining”, m.sc. thesis, university of thapar-patiala, chaps.1. [9]. sourabh k. s., 2008, “experimental investigation of the dry electric discharge machining (dry edm) process”, m.sc. thesis, department of mechanical engineering indian institute of technology kanpur. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 143 table (1): the experimental design matrix with coded factors. experiment no. current gap distance machining time 1. 0 0 0 2. 1 1 1 3. 0 0 0 4. 0 0 0 5. -1 1 1 6. 0 1 0 7. -1 0 0 8. 0 0 0 9. -1 -1 1 10. -1 -1 -1 11. 0 0 -1 12. 0 0 1 13. 0 0 0 14. 1 0 0 15. -1 1 -1 16. 0 0 1 17. 0 -1 0 18. 1 -1 -1 19. 1 1 -1 20. 1 -1 1 table (2):specifications of edm machine machine used cnc edm (znc 435l) electrode stainless steel electrode polarity positive workpiece copper alloy dielectric solution tap water table 3: different variables used in the experiment and their levels. variable coding level -1 0 1 current (a) a 4 6 10 gap distance (mm) b 0.3 0.4 0.5 machining time (min) c 5 7 10 al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 144 table 4: regression coefficients for hole diameter. term coefficient se coefficient t p constant 129.439 9.219 14.040 0.000 current (a) -93.998 4.348 -21.620 0.000 gap distance (b) 23.230 4.243 5.475 0.000 machining time (c) 45.089 3.982 11.323 0.000 a*a 86.997 8.532 10.197 0.000 b*b -32.037 7.100 -4.513 0.001 c*c 1.891 7.780 0.243 0.813 a*b -28.376 5.175 -5.483 0.000 a*c -10.173 4.580 -2.221 0.051 b*c 19.628 4.849 4.048 0.002 r 2 = 98.97% r 2 (prediction) = 93.24% r 2 (adjusted) = 98.04% figure (1): cnc electric discharge machine (znc 435 l). al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 145 figure (2): normal probability plot. figure (3): residual plot. figure4: variation of hole diameter according to change of gap distance and machining time. hold value is: current = 7 a. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 146 figure5: variation of hole diameter according to change of current and machining time. hold value is: gap distance = 0.4 mm. figure (6): variation of hole diameter according to change of current and gap distance. hold value is: machining time = 7.5 min. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 147 figure (7): optimization plot. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 569 the impact of adding copper to aluminum on microstructure and hardness assistant lecturer: nawzad j. mahmood , commission of technical education, technical college/kirkuk, refrigeration and air conditioning engineering department email:nmeznawi@yahoo.com received 23 march 2015 accepted 27 august 2015 abstract solidification and microstructure are important indexes to evaluate the mechanical properties and qualities of casting. directional solidification describes solidification that occurs from the farthest end of the casting. this study is devoted to show the directional solidification effect of copper-aluminum alloy (95%al,5%cu) on hardness and microstructure.. this was achieved by varying the temperature of water flowing from the base in three different temperatures (0,10,20 )ºc by using a chilling base. it was concluded that the difference in the solidification of the three samples was due to the different cooling rates applied and as a result of low temperature of sample, which the chilling base temperature was (0ºc) compared with the rest of the samples which led to soften the dendrites crystals, and highest hardness reading obtained due to low temperature of the cooling base of sample. key words: directional solidification, hardness, microstructure, chilling base, al-cu alloy. دراسة تأثير اضافة النحاس الى االلمنيوم على البنية المجهرية والصالدة ملخص البحث ان البنية المجهرية للسبائك وطريقة تجمدها يقيم الخواص الميكانيكية و نوعية السبيكة المستخدمة. ان التجمد االتجاهي يوصف نحاس -الى إظهار تأثير التجمد االتجاهي لسبــــــيكة المنيومالتجمد من ابعد نهايةفي القالب المعدني. و يخصص هذه الدراسة ٪ نحاس( على الصالدة والبنية المجهرية .. وتم تحقيق ذلك من خالل تغيير درجة حرارة المياه المتدفق من 9٪ المنيوم، 59) عالية وبثالثة درجات حرارة خالل القاعــــــدة المصنوعة من معدن النحاس النقي وذلك لضمان الحصول على موصلية حرارية ( درجة مئوية حيث تم استخدام القاعدة كمصعقة للتبريد, وتبين ان الفرق الحاصل في درجة حرارة القاعدة 00، 00، 0مختلفة ) رقم ادى الى الحصول على معدالت تبريد مختلفة للعينات الثالثة المستخدمة فــــــي الدراسة وكنتيجة لكون درجة حرارة العينة ( االقل بالمقارنة مع بقية العينات وهذا ما ادى الى تنعيم البنية المجهرية و كذلك الحصـــــول على اعلى قيمة للصالدة بالمقارنة 0) مع بقية العينات المسثخدمة في الدراسة. س.نحا-التجمد االتجاهي, الصالدة, البنية المجهرية,قاعدة تبريد, سبيكة المنيوم كلمات الداللة: introduction aluminum is the third most plentiful element known in industrial, where oxygen and silicon exist in greater quantities. aluminum, chemical symbol al, has the atomic number 13.. aluminum, like al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 570 copper, silver and gold, crystallizes with the face-centered-cubic arrangement of atoms, common to most of the ductile metals. lightness is the outstanding and best known characteristic of aluminum. the metal has an atomic weight of 26.98 and a specific gravity of 2.70, approximately one-third of the weight of other commonly used metals [1]. aluminum has a density of only 2.7 g/cm 3 , approximately one-third as much as steel (7.83 g/cm 3 ), copper (8.93 g/cm3), and brass (8.53 g/cm 3 ). it can display excellent corrosion resistance in most environments, including atmosphere, water (including salt water), petrochemicals, and many other chemical systems[2]. aluminum-copper alloys are typical solid-solution alloys[3] and the eutectic phase consists of alternate lamella structure of α phase(ductile) and θphases al2cu ( brittle) [4]. copper (cu) has the single greatest impact of all alloying elements on the strength and hardness of aluminum casting alloys, both heat-treated and non heat-treated and at both ambient and elevated service temperatures. copper also improves the mach inability of alloys by increasing matrix hardness, making it easier to generate small cutting chips and fine machined finishes. on the downside, copper generally reduces the corrosion resistance of aluminum; and, in certain alloys and tempers, it increases stress corrosion susceptibility [5].casting and solidification of metals are critically dependent upon temperature, rate of cooling and thermal mass. thus, heat transfer between the solidifying metal, the mold , and surroundings is a key factor in the properties of the final solidified metal [6]. the cooling rate reflects the heat extraction rate and is measured in k/s. cooling rate is closely connected to the solidification rate which can define either the velocity of solidification front or as liquid -solid phase transformation rate, measured in units of m/s or s -1 respectively[7]. the following paragraphs provide a summary of studies on the effect of directional solidification of aluminum alloys on hardness and microstructure: m. gu¨ndu¨z a,*, e. c¸ adırl (2002) directional solidification experiments have been carried out on different al–cu alloys as a function of solidification parameters, temperature gradient g, growth rate v, and composition[8]. l.a. dobrzañski a,*, r. maniara a, j.h. sokolowski (2007) the solidification process was studied using the cooling curve and crystallization curve at solidification rate ranging from 0,16 ºcs-1 up to 1,04 c[9]. hui chen, yu shi chen, x. wu, s.n. tewari(2003) studied the history dependence of primary den-drite spacing during directional solidification of binary metallic alloys and interdendritic convection[10]. h. kaya a ,e cadirli b ,u boyok a ,n. marasli (2008) studied the variation of micro indentation hardness with solidification and microstructure parameters in the al based alloys [11]. experimental procedure equipments used in the present study :  sensitive balance device three digits.  electric furnace.  grinding machine (ap04-wet grinder -buehler metaserv machine).  polishing machine 100 v, 50hz.  digital camera with resolution 12 megapixle. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 571  thermocouple k-type (up to 1200 o c)  microscope (euromax trinocular metallurgical micriscope. 400x).  portable hardness tester (th120).  water pump (600ltr/hr , 220v, 10 w).  electric heater (220v, 1400w)  thermometer (-50-70 o c). preparation of casting the chilling base was made from pure copper because of its high thermal conductivity and isolated by glass wool and covered by plate as shown in figure (2), and using a submerge electric pump to circulate the water in the system, then the tests was done by the following procedure: 1-operating the cooling system by using ice in the water tank to reach (0 º c) temperature in the chilling base for sample number (1) before the casting procedure about (5 minutes) to stabilize temperature on (0 º c) and using two thermometers to record the inlet and outlet water temperatures, then the casting was done by the following steps: a) using two thermocouples in two different places (k-type thermocouple) with a digital camera to record the casting temperatures specially during the first temperature drop as shown in figure (3) and a digital camera used to record temperatures. b) using an electrical furnace to melt the aluminum by using a graphite crucible which was initially preheated in the furnace until reaching to temperature (700 º c) then adding the copper to the casting. c) pouring the molten metal into a carbon steel mold ( the dimension of the carbon steel mold shown in figure(4). followed by leaving the casting to cool down to room temperature. 2the second step was done by repeating step (1) and using electric heater to heat the water to reach temperature of the circulating water to (10 º c) for sample (2). 3the third step was done by repeating step (1) and using electric heater to heat the water to reach temperature of the circulating water to (20 º c) for sample (3). preparation of specimens the preparation procedure included cutting specimens into three parts by a hand saw ( each with length 30 mm) and each sample was lettered an numbered, then the following steps were preformed to prepare specimens for microstructure and hardness tests:  wet grinding was performed by using emery paper in grades (320, 400,600,800,1200)  polishing procedure by using alumina particles oxide (al2o3) with size 0.3µm then specimens were cleaned by water and degreased with ethanol and dried for (microstructure and hardness tests.  etching : the etchants used to reveal the microstructure of the specimens consisted of : al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 572  99.5% distilled water.  0.5% hydrofluoric acid (hf) [12]. results and conclusions 1-cooling rates for chilling die castings from the results obtained in the experiments have been able to observe the time temperature curves illustrated in the figures (5,6 and 7) , it was noticed that the most of the heat loss was through the chilling base (80%); in addition to secondary cooling of the alloy will be by the environment encapsulating the die (20%) [13]. the geometrical shape of the mold cavity has direct effect on progressive and directional solidification, type geometries divergent heat flow occurs, which causes that area of the casting to cool faster than surrounding areas; this is called an end effect[14]. the aluminum-copper timetemperature diagram is a simple eutectic systems the basic process of solidification and morphology formation is as follows. when the temperature goes below the liquidus line, the solid-solution phase (α) solidifies first, while most of the copper remains in liquid form. as the temperature approaches the solidus, the α solid phase becomes more enriched with copper. when the temperature falls below the solidus temperature in alloys containing less than the maximum solubility (5wt% cu), solidification is complete to the solid-solution phase condition (α), two terminal solid-solution phases (α and θ) separate out simultaneously from the molten liquid. on cooling below the eutectic temperature, a network of eutectic forms in the residual liquid surrounding the dendrites or grains of primary α. it was observed that the high temperature drop took effect in the three specimens till approximately (100ºc) as then the temperature started gradually cooling down till it reached room temperature. it was also observed that the temperature difference in cooling time of specimen number (1) ,(0ºc) was used as a chilling temperature which recorded the less cooling effect compared to specimen (2) were (10ºc) was used as a chilling base (23.33 min.) was recorded as solidification time, whereas the difference between specimen (1) and specimen (2) was (8.67 min.) with regard to specimen number (3), it was observed that cooling rate was decreased due to temperature rise of the chilling base to (20ºc), it was recorded the cooling time (25.5 min.) as a cooling time, this leads to concluding that for lower temperatures the cooling rate increases and this what was proved by the researcher[15]. 2-microstructure results the micro scale (microstructure) is of the order of 10 -6 to 10 -5 m. the micro scale describes the complex morphology of the solidification grain. the importance of microstructure to the properties of alloys has long been recognized in the microstructure test, grain size, the distribution of second phase particles (al2cu) are important in determining the behavior of the most structural metals. direction of heat flow out of a mold also impacts where the last metal freezes and where solidification shrinkage takes place cooling rates also determine the subsequent grain size of the solidified metal[6] . inspecting the curves of time-temperature, it was observed that the two main factors influence the microstructure is cooling rates which reflects the temperature loss and cooling rates is linked to solidification rate which defined as solid solution phase and measured by (m/sec), figure-8 (1a,2a and 3a) where the temperature of chilling base was fixed to (0 o c) compared to the microstructure of the specimen facing the chilling base this was due to the grain refining of the microstructure for specimen number (1) whereas in figures (2a,2b and 2c) and (3a,3b and 3c) it was observed that the grain size is a little bigger compared to specimen (1) and this what was proved by the researcher [16]. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 573 3-hardness results to evaluate the influence of solidification on the properties of the castings hardness measurements as applied to specific classes of materials convey different fundamental aspects of the material. thus, for metals hardness is directly proportional to the uniaxial yield stress at the strain imposed by the indentation. figures (9) inclusive shows the relationship between the properties and characteristics of the various alloy groupings and especially the alloy used in the study 2xx(1) which was the same results as in the present study. the relation between brinell hardness test and the different chilling base temperatures figure (10), where the sample had been cut into three pieces as shown in figure (11) and the series (1a,1b and1c) are the position of the sample in the mold which had been cut into, its observed that the series number (1) for the three specimens with a temperatures(10 and 20) º c has recorded the maximum values of hardness due to its direct contact with the chilling base which led to a grain refining and this factor is enhanced with the results if microstructure tests, while the specimens (2a,2b,2c, 3b and 3c) recorded a decrease in the hardness values due to its far distance with the chilling base which led to rough grain structure. referencs [1] ron cobden, alcan, banbury.1994 aluminum: physical properties, characteristics and alloys eaa european aluminum association,pp8,9,10 [2] asm handbook, metals hand book 9th edition, volume13, 1992. [3] asm handbook,2004 metallography and microstructures, volume 9, 107. [4] raymond a.higgins 1999,applied physical metallurgy engineering sixth edition,415 [5]d.apelian, aluminum casting alloys ,enabling tools for improved performance,p 7,8, 1992. [6] kreith f,timmerhaus k. and lior n.show r.k.bell k. etal 2000.. applications the crc handbook of thermal parameters in the al based alloys [7] dmitry g .eksan, 2008 physical metallurgy direct chill casting of aluminum alloys crcpress,19. [8] m. gu¨ndu¨z a,*, e. c¸ adırlı 2002directional solidification experiments have been carried out on different al–cu alloys [9] l.a. dobrzañski a, r and. maniara a, j.h. sokolowski b2007,, archives of materials science and engineering. [10] hui chen, yu shi chen, x. wu, s.n.2003 tewari studied the history dependence of primary dendrite spacing during directional solidification of binary metallic alloys and interdendritic convection, journal of crystal growth 253 (2003) 413–423chemical engineering department, fenn college of engineering, cleveland state university, 1960 east 24th street stilwell hall 455, cleveland, oh 441152425, usa international scientific journal volume 28 issue 2 ,pp 105-112, [11]h. kaya a, e. c¸adırlı b, u. bo¨yu¨ k a, n. maras variation of micro indentation hardness with solidification and microstructure, a erciyes university, 2008 faculty of education, al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 574 department of science education, kayseri, turkey, applied surface science 255 pp 3071–3078 [12] c.a.keyser, 1962 basic engineering metallurgy, prentic hall, inc(usa), 2ed,pp 297,303 [13] dr. dmitri kopeliovich. 2011 direct chill (dc) casting. dmitri_kopeliovich, substances and technologies. [14] directional solidification and progressive solidification,2008 wikipedia, free encyclopedia. [15] girishia.h.n.k.v. sharma2008, effect of magnesium and undirectional solidification on strength and microstructure of al-cu-mg alloy international journal of emerging technology and advanced engineering issn 2250-2459,iso 9001vol.3 issue 6 june 2013. [16] morteza amoorezai,sebastian and gurvich, nokolas provatas, 2010 acta materiala 58pp 61156124 figure (1a): shows photographic of figure (1b): shows sketch diagram of the the testing system testing system figure (2): demonstrates the model of chilling base water inlet water out let chilling base carbo n steel mold chillin g base inlet wate r out let water submerged water pump al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 575 figure (3): demonstrates the digital camera and thermometer reader figure (4): demonstrates the carbon steel die dimensions figure(5): shows timetemperature curve for specimen number(1) using a chilling temperature (0ºc) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 576 figure(6): shows timetemperature curve for specimen number(1) using a chilling temperature (10ºc) figure(7): shows timetemperature curve for specimen number(1) using a chilling temperature (20ºc) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 577 figure(8): shows microstructure tests al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 578 1xx.xal 99% or greater al alloys grouped by major alloying elements 2xx.xcu 3xx.x si with added cu or mg 4xx.x si 5xx.x mg 7xx.xzn 8xx.xsn 9xx.x other elements 6xx.x unused series figure(9): shows the relation of adding alloying elements on tensile strength, hardness, and impact sensitivity [1] figure (10): shows the relation between brinell hardness test and the chilling temperature figure(11): shows the position of the specimens which had been cut into for brinell hardness test article al-qadisiyah journal for engineering sciences 12 (2019) 007–016 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hayder.althabhawi@uokufa.edu.iq (hayder w al-thabhawee) https://doi.org/10.30772/qjes.v12i1.581 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. reinforcing the octagonal web openings of castellated beam by steel rings hayder w. al-thabhaweea* and abbas a. mohammeda adepartment of civil engineering, faculty of engineering, university of kufa, najaf, iraq. a r t i c l e i n f o article history: received 21 january 2019 received in revised form 05 march 2019 accepted 06 march 2019 keywords: castellated steel beam spacer plate web post finite element seel ring stiffener. a b s t r a c t castellated steel beams are section steel members with hexagonal or octagonal web openings which they are made from standard hot rolled steel section i or h. the main advantage of these members is their economic material. an additional important advantage is a possibility to guide service ducts through the openings. the presence of the web openings influences the members’ failure behavior around the openings, new local failure modes will come into existence, such as the buckling of the web post between the openings, or yielding around the openings. castellated beams with octagonal openings usually fail due to web post-buckling because of the increase in depth. the current study focused on improving the behavior of the castellated beam with octagonal openings using steel ring stiffener and adjusting the best dimension and distribution for the stiffeners. all the models of specimens have been fabricated from a parent i section (ipe 140). the models have been modeled and analyzed using finite element software ansys (version 15). the analysis results showed that reinforcing octagonal castellated beams by adding steel ring stiffeners around octagonal web opening was very active way to increase the ultimate load for long span, where the ultimate load of reinforced octagonal castellated beam increased up to (286%) compared with parent i-section beam. economically, the percentage of additional steel material which used to expansion and reinforce the castellated beams (spacer plate and steel ring stiffeners) was (36%) when compared with the weight of parent i-section beam. while the allowable load at deflection (l/180) was (260 %) compared to the allowable load of parent section at the same deflection. the gained benefit was increasing the ultimate and allowable load of reinforced octagonal castellated beams by (186%) and (160%) respectively by using additional steel material only (36%) from the weight of parent isection, which the additional steel material consisted from the spacer plates and steel rings. also, the results indicate that the best dimensions for the ring were when thickness equal to the web thickness of the parent section and the width equal to the half of the parent section flange width. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction castellated beams are steel i or h section members with evenly spaced hexagonal or octagonal web openings. sometimes, it can be added spacer plate to obtain octagonal opening with increasing the depth of members as shown in fig. 1. the castellated steel beam is one of the important improvement in the field of steel structures. most of the castellated members used nowadays are made by thermally cutting the web of a hotrolled parent section according to a certain pattern as shown in fig. 2, after that, the obtained halves are welded together to form a member with http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i1.581 8 hayder w. a l-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 a higher web and with hexagonal web openings. the process of producing castellated beams from rolled sections has been used in steel construction since the late 1930s boyer [1]. today the castellated beams are produced widely and the production cost has been reduced due to the development of equipment of the two main steps, the cutting, and welding, which made them as an alternate choice to open-web steel joists in floor systems. figure 1: castellated steel beam with hexagonal and octagonal opening figure 2: thermally cutting the web of a hot-rolled parent section for tested specimen the castellation process increases the overall depth of the parent section, this increasing contribute effectively in modifying the strength of castellated beams in comparison with the strength of parent section. the other type of castellated beams is with octagonal openings which could be produced by adding addition steel plate between the two parts of the tee sections, this steel plates called “spacer plates” ” (zaarour and redwood, [2]),and this raises the depth up to two times of parent section depth, as shown in fig. (1-b). the existence of openings in the web in this type of steel members leads to redistribute the stresses around the openings which as a results effects on its collapse behavior soltani et al. [3]. also, the presence of these openings decreases the stiffness of beams which leads to larger deflection. castellated beams with octagonal openings had larger web depth than castellated beams with hexagonal openings and this lead to an increase in the slenderness of web post which as result lead to failing the web by buckling. the present research aims to establish a numerical study to develop strength the castellated beams with octagonal openings by reinforcing the openings with steel ring as shown in fig. 3 and adjusting the best dimensions and distribution for the steel rings. the numerical study deals with both materials and geometric nonlinearity in analyzing the tested beams to perform the finite element using (ansys ver.15) program. figure 3: octagonal castellated steel beam reinforced by steel rings numerical models using finite element software ansys (ver. 15) are developed in order to validate the modelling process. the verification process included simulation the experimental specimens numerically using ansys program and comparing the results with those conducted from experimental results. 2. previous studies and research gap sung c. lee, et. al. [4] three numerical models have been analyzed of plate girder using adina (“automatic dynamic incremental nonlinear analysis”, 1999) program, and evaluate the same model with three stiffeners plate. shear analogy model has been used to explain the buckling behavior of the shear web. the results showed that the transverse stiffeners contribute effectively in strengthening the web of a beam in spite of the stiffeners are not subjected to a compression force. ehab ellobody [5] : the interaction buckling failure modes have been studied experimentally and nautically for castellated beams with normal and high strength. the experimental program consists of six full-scale beams with different lengths and depths. then, the numerical results verified against experimental tests. after that a numerical parametric study to investigate the effect of beam length, the geometry of cross section, and steel strength. they concluded that the incidence of buckling of web leads to a significant decreasing in the failure load of beam, also the results shown that using high strength steel increasing considerably the failure load. also, it observed that the lateral torsional buckling more likely to happen in normal strength castellated beam, while high strength castellated beam tends to fail in web distortional buckling. wakchaure m.r [6]: an experimental parametric study to investigate the effect of increasing the depth of castellated beams with hexagonal opening shape, for various failure modes. the tested beams were simply supported with two applied point loads. the parent beam depth increased by 40,50 and 60% with angle 60o of hexagonal opening in process of castellation. the results showed that the increase of depth increases the moment carrying capacity, and the castellated beam behaves satisfactorily with increasing the depth 40, 50 % up to maximum depth 60 % of parent beam which shows hayder w. al-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 9 average results. they also recommended providing a transverse stiffener to under applied load in order to avoid local failure and reinforcing the beam’s weak sections. jamadar and kumbhar [7] : a parametric study concerned about optimizing castellated beam with circular and diamond opening shape through two factors, the first was the ratio between the castellated beam overall depth to opening depth, the second was the ratio between the spacing between openings to opening depth. the numerical models were modeled through finite element software abaqus, the models were following the eurocode 3 provisions. the results showed the optimized dimension for diamond shape opening castellated beams was when the opening depth of 0.67 times original beam depth, and for circular opening shape castellated beams when opening depth 0.73 times overall beam depth. the castellated beams with diamond shape gave a better strength than the other openings shape. althabhawee [8], analyzed experimental results of six hexagonal castellated steel beams and parent section (control beam). he investigated the effect of hexagonal opening geometry and number on the behavior of castellated steel beams that have the same span and ratio of expansion. the test results showed that best dimension of castellated steel beam was a ratio of length to opening space (l/s =8.0) and a ratio of opening high to beam depth (h/h=0.56) and the failure load of castellated steel beam was increased about (50%) stronger than the control beam. in 2018, al-thabhawee and al-kannoon [9] used finite element models by ansys14 software to improve the behavior of hexagonal and octagonal castellated beam with spacer plate by reinforced opening by steel ring. the increment of castellated beam depth by spacer plate leaded to post buckling in its web and to many other modes of failure when these beams are subjected on loading.” it was revealed that using ring steel stiffeners can reduce the stress concentration around the edge of openings and improve the behavior of these beams by increasing the failure load and minimizing the deflection. from the previous studies, it can be concluded that due to ease of manufacturing castellated beams with hexagonal or circular opening shape, so most of the researches focused on these types of castellated beams and they are widely used in different constructions, these lead to lack in researches that concern about the castellated beams with octagonal openings (by additional spacer plate) and examining the structural behavior of this type of castellated beams, in addition, most of the research indicated the failure of this type happened due to local buckling in web portion. also, most of the studies focused on optimizing the dimension of castellated and as noticed there is no studies has been carried out to improve castellated beam with octagonal openings to avoid local failure. it noted that increase in the strength of castellated beams leads to significant changing in the behavior. also, the previous studies deal with a response, failure modes and the interaction between the failure modes. 3. finite element analysis the calibration process has been prepared by comparing the experimental results with the result of nonlinear finite element models. two types of non-linearity have been implemented in the analysis of numerical models in order to determine results as close as to real cases, which they were geometrical and material non-linearity. the element (shell 181) was chosen to simulate the castellated beams models, as shown in fig. 4. the element used to the model of steel i-section and stiffeners. it consists of a four-node element with six freedom degrees per node. this element is well suited for analyzing application with nonlinear behaviors [10]. figure 4. sell181 element (ansys) 4. verification of finite element models three experimental specimens (control, cbc-02, and cbc-03) tested by al-thabhawee and mohammed at laboratories of engineering faculty of kufa university and selected to verify the analysis using ansys software (ver. 15) as shown in fig. 5. these beams were loaded by one concentrated load at mid-span. the dimensions and properties of a castellated steel beam in experimental and numerical work were clarified in fig. 6. figure 5: test setup for specimens the analysis of castellated beams models performed to be calibrated with results executed from the experimental tested castellated beam. the verification process focused on verify control beam (ipe140) and octagonal castellated beams with and without reinforcement with properties and dimensions as same as the experimental program. the material properties were obtained by tension tests on flat tensile specimens according to astm [11] as clarified in fig. 6. the results of models obtained by the finite element analysis which included the load versus deflection curves have been compared with experimental load 10 hayder w. a l-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 versus deflection curves. figure 6: dimension and properties for tested specimen in addition to the distribution of stresses which represent the stress concentration along the beam areas, for tested beams were presented in the following paragraphs. the finite element models for the parent section and octagonal castellated beam with six openings and meshing are displayed in fig. 6. figure 7: models of parent and castellated steel beams the numerical models for tested beams and them mesh shown in fig. 7. the results showed that the numerical ultimate load capacities were a little greater than the experimental ultimate load capacities for the tested cases. the results showed a convergent response between the experimental results and finite element solution through the range of loading. these results confirm that it could be used the numerical model to deal with castellated steel beam specimens for this load and support conditions as shown in load-deflection response curves for the numerical and the experimental work for specimens in fig. 8. the von-mises stress distribution of the model results at failure load is shown in fig. 9 at failure load. it could be noticed that the numerical models’ behavior is similar to experimental behavior. figure 8: experimental and numerical load -deflection curves for specimens control beam’s model octagonal castellated beam’s model reinforced castellated beam’s model hayder w. al-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 11 figure (9): distribution of von-mises stress for specimens 5. reinforcing the octagonal web openings the second portion of the numerical study after modelling the tested castellated beams and calibrate the process of modelling by comparing the numerical results by experimental results, a study has been established. based on the experimental program the steel ring stiffener for the octagonal castellated beam with expansion depth ratio (1.99) gave the maximum results, so the study focused on this type of stiffener and this expansion ratio of the castellated beam.. the verified finite element modelling process was used to study the effects of using different span length with different properties for ring stiffener which included using the steel ring stiffeners in regions where the maximum moment will be located in manner similar to reinforcing, also study the effect of thickness and width of rings for castellated with octagonal openings. the specimen’s length was (5.50m) length. fig. 10 displays the key details and dimensions of the steel ring which used as reinforcement to strengthen the octagonal openings of castellated beam. the steel rings were with thickness (t=5 mm) and width (b=36.5 mm). all the models were modelled by using the finite element software ansys (ver. 15). fig. 11 summarizes the dimensions’ properties of the studied castellated beams and the parent section. these parameters used to study the effect of steel ring parameters on the load versus deflection response and allowable load also the increment in weight due to these parameters. control beam’s model at failure load = 89 kn octagonal castellated beam’s model at failure load = 159 kn reinforced castellated beam’s model at failure load = 254 kn 12 hayder w. a l-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 figure 10: dimensions of models figure 11: characteristics of ring steel stiffener fig. 12 illustrates the model of the reinforced octagonal castellated beam by welding steel ring stiffener around octagonal opening, which is modeled using ansys software. the analysis results showed that the ultimate load of castellated beam with octagonal opening (with adding spacer plate) is (110 %) more than the ultimate load of the parent beam. figure 12: model of reinforced castellated beam in addition, the ultimate load of the reinforced castellated beam by steel ring stiffeners was improved up to (186 %) more than the ultimate load of parent section, while the ultimate load of reinforced castellated beams is improved to (76 %) compared to the ultimate load of castellated beam without reinforcement, as illustrated in fig. 13. hayder w. al-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 13 figure 13: load deflection curves of castellated beam with and without ring stiffeners most of the times, flexural members are required by ibc (international building code) [12] to be designed to have adequate stiffness to limit deflections. in this study, the allowable load of castellated beams estimates based on the limited deflection that ibc is recommended (l/180). for model specimen the maximum deflection which its length was (5.5 m), the deflection was (30 mm), and based on that results the comparison between cases of study have been prepared. the results based on this criterion showed that the allowable load of octagonal castellated beam without steel ring is (100 %) more than the allowable load of the parent beam and the allowable load of the reinforced octagonal castellated beam by steel ring stiffeners was reached up to (160 %) more than the allowable load of parent section, while the allowable load of reinforced castellated beams by steel ring stiffeners is improved to (60%) compared to the allowable load of castellated beam without steel ring stiffeners, as clarified in fig. 13. in the other hand (economically), the total weight of reinforced octagonal castellated beam increase with using spacer plate and steel ring stiffeners. in the presented work, the percentage of original section and additional steel material which used to expansion and reinforce the castellated beams was (136%) compared to the weight of parent beam. the benefit gained was increasing ultimate and allowable load of reinforced octagonal castellated beams by (186%) and (160%) respectively with using additional steel material only (36%) as shown in fig. 14. figure 14: ratios of weight, ultimate load and allowable load of models due to high strength of reinforced octagonal castellated beam as shown in results, it could use compositely with concrete since the concrete slab contributes in increasing the ultimate load of composite section alkhekany and muteb [13]. the finite element results showed that reinforcing castellated beams by steel ring improved the stress distribution compared with non-reinforcing castellated beam and parent section, as displayed in fig. 15. also, it can be observed that the use of ring steel stiffeners contributes effectively in minimizing the deflection and increasing the ultimate and allowable load, this may do to that the steel rings reduced the stress concentration around the openings. figure 15: stress distribution for castellated beam and control beam of reinforcing study 5.1. effect of thickness of ring steel stiffeners on allowable load the first parameter was ring thickness. different thicknesses have been studied based on the thickness of the web (as a ratio of web thickness). the thicknesses were (1.5,1.25, 1.5,1.25,1,0.75 and 0.5) from web thickness for the same width which was equal (0.5) flange width. 14 hayder w. a l-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 figure 16: effect of ring thickness on the behavior of castellated beams figure 17: allowable load capacities of different ring thicknesses the models were analyzed by nonlinear finite element method using the ansys program. fig. 16 summarized the effect of thickness on the behavior of the castellated beam. it could notice that thickness contributes effectively in increasing the stiffness of ring and thus increase allowable load capacity, also it noticed that effect of increasing the thickness become less effective when the ring thickness exceeds the web thickness. as shown in fig. 17. 5.2. effect of width of ring steel stiffeners on allowable load the other parameter was the width of the steel ring stiffener; different sizes of width have been studied based on the flange width. the steel ring width were (1,0.75,0.5,0.25) times of flange width and for the same thickness which was equal to the web thickness. all the models were analyzed numerically using the nonlinear finite element method. fig. 18 summarized graphically the load versus deflection response for the different width of the stiffener steel ring. it could be noticed that the effect of the steel ring width become negligible if it exceeds half of the flange width. fig. 19 summarized the allowable load capacities for the different steel ring stiffeners widths, in addition to the control beam and nonreinforced castellated beam. the results confirmed that the width of steel ring stiffeners effect become less effective in increasing allowable load when it exceeds (0.5) times of flange width. figure 18: effect of ring width on the behavior of castellated beams figure 19: allowable load capacities of different ring 5.3. distribution of openings reinforcing the third parameter was using steel ring stiffener on the places where the maximum moment concentrated, which in case of simply supported beam concentrated in the mid-span. five cases of reinforcing octagonal castellated beam by steel ring stiffeners have been studied in this study. the steel ring stiffener added dependent on the distribution of bending moment along the span. the cases categorized according to the ratio between the reinforced length (lr) of octagonal castellated beam and the effective length of beam (l), the five cases ratios were (0.2, 0.4, 0.6,0.8 and 1) as described in fig. 20. the results showed that steel ring stiffeners contribute effectively in improving the strength of castellated beam with octagonal openings, the effect of adding rings mainly enhancing the large web depth of castellated beam with octagonal openings which as aforementioned produced by adding the spacer plate between the two halves of hexagonal castellated beam, and this process increases the depth about two times of the depth of parent i section, which as a result increases the slenderness of web post and made it tend to failure by buckling. in case of applying a concentrated load at mid-span the maximum moment will be concentrated under point load, so to decrease the number of used steel rings will be added in areas where high moment concentration. the analysis results showed that rings effectively in increasing the strength of castellated beams as shown in fig. 21. the analysis results showed that steel ring stiffeners increase effectively the allowable load as presented in fig. 22. hayder w. al-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 15 figure 20: reinforcing cases of different (lr/l) ratios. figure 21: loaddeflection curve of distribution steel ring stiffeners. figure 22: allowable load for deferent cases of reinforcing by steel ring stiffeners. 16 hayder w. a l-thabhawee and abbas a. mohammed /al-qadisiyah journal for engineering sciences 12 (2019) 007–016 6. conclusions 1. the finite element model used in the present study is able to simulate the castellated beams with and without stiffeners with a good agreement between response. the predicted ultimate load capacities are in good agreement with the experimental results. 2reinforced octagonal castellated beams by steel rings a very active way to increase the ultimate and allowable load for long span castellated beams. the ultimate and allowable load of reinforced octagonal castellated beam increased (186%) and (160%) respectively, while the additional steel material which used to expansion and reinforces the castellated beams (spacer plate and steel ring stiffeners) increased only (36%). 3furthermore, the results showed that ultimate load of reinforced was (76 %) larger than ultimate load of non-reinforced castellated beam, while the allowable of reinforced castellated beam was (60 %) larger than the allowable of non-reinforced castellated beam. 4the results showed that using a steel ring stiffeners with a thickness larger than web thickness become less effective in increasing allowable load. 5numerical results indicated that by using steel ring stiffeners with a width larger than half of the flange width did not contribute effectively in increasing the allowable load proportioned to reinforced castellated beam with ring width equal to half flange width. 6the distribution of steel ring stiffeners according to the applied load contribute effectively in decreasing amount of addition steel material and consume effectively in preventing web post-buckling and such enhancing the allowable load capacity. references [1] j. boyer, castellated beams-new developments, aisc engineering journal, 1(3) (1964) 104. [2] w. zaarour, r. redwood, web buckling in thin webbed castellated beams, journal of structural engineering, 122(8) (1996) 860-866. [3] m. soltani, a. bouchaïr, m. mimoune, nonlinear fe analysis of the ultimate behavior of steel castellated beams, journal of constructional steel research, 70 (2012) 101-114. [4] s.c. lee, c.h. yoo, d.y. yoon, behavior of intermediate transverse stiffeners attached on web panels, journal of structural engineering, 128(3) (2002) 337-345. [5] e. ellobody, interaction of buckling modes in castellated steel beams, journal of constructional steel research, 67(5) (2011) 814-825. [6] m. wakchaure, a. sagade, v. auti, parametric study of castellated beam with varying depth of web opening, international journal of scientific and research publications, 2(8) (2012) 2250-3153. [7] a. jamadar, p. kumbhar, parametric study of castellated beam with circular and diamond shaped openings, international research journal of engineering and technology, 2(2) (2015) 715-722. [8] h.w. al-thabhawee, experimantal study of effect of hexagonal holes dimensions on ultimate strength of castellated steel beam, kufa journal of engineering, 8(1) (2017) 97-107. [9] h.w. al-thabhawee and m. a. al-kannoon, ‘improving behavior of castellated beam by adding spacer plat and steel rings, journal of university of babylon, engineering sciences , 26 (4) (2018), pp.331 344. [10] a.f. inc, fluent 15.0, help-user’s guide, fluent inc, (2012). [11] a. standard, a370, standard test methods and definitions for mechanical testing of steel products, west conshohocken, pa: astm international, (2005). [12] i.c. council, i.c.o.b. officials, b. officials, c.a. international, s.b.c.c. international, international building code 2000, dearborn trade publishing, 2000. [13] a.m. al-khekany, h.h. muteb, effect of composite action of concrete slab on unsymmetrical steel plate girder under combined bending and torsion moments, alqadisiyah journal for engineering sciences, 10(3) (2017) 338-351. article al-qadisiyah journal for engineering sciences 12 (2019) 001–006 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mukeab2014@yahoo.com (muna k. abbass) https://doi.org/10.30772/qjes.v12i1.580 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. optimization of friction stir processing parameters for aluminum alloy (aa6061-t6) using taguchi method muna k. abbassa* and noor alhuda b. sharhana adept. of production engineering and metallurgy, university of technology baghdad –iraq. a r t i c l e i n f o article history: received 28 december 2018 received in revised form 25 february 2019 accepted 03 march 2019 keywords: aluminum alloy friction stir processing taguchi method mechanical properties a b s t r a c t this work is devoted toward optimization of the parameters of the friction stir processing (fsp) which effect on tensile strength of aluminium alloy aa6061-t6 of 6mm thick plate by applying a certain number of tests utilizing the taguchi method. design of experiment (doe) has been applied for the determination of the most important parameters influencing ultimate tensile strength. fsp was achieved under three different rotation speeds (800,1000 and 1250) rpm, different transverse speeds (16,25 and 32) mm\min, and number passes(1,2 and 3) in the same direction and tool tilt angle was 2° with using threaded cylindrical pin profile. the best fsp parameters were 1250 rpm and 32 mm\min and two passes. it was found that the higher hardness value was 75hv in stir zone center and then decreases toward the tmaz, haz and the base metal. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction aluminum alloys are important for many applications such as aerospace and automotive industries etc…., because of their light weight and high strength to weight ratio [1]. because of the good properties of aluminum alloy 6061-t6, light weight, good strength, good erosion and corrosion properties, it is widely used in marine areas, cars and aircraft [2]. homogenising and refining the grain structure of the alloy get better mechanical properties. its ability be carried out via an assortment of processes such as high pressure-torsion (hpt), thermo mechanical treatment (tmt), accumulative roll-bonding (arb), equal channel-angular process (ecap), and so on. this process exhaustion time and complex [3]. recently friction stir processing (fsp), an innovative approach was developed for grain refinement and fabrication of surface composite materials. its basic principles are the same as those of fsw. fsp is quite a promising method for the enhancement of metal properties [4]. this process causes high strain rates and intensive plastic deformation [5]. through (fsp) a rotational tool pin sticks to the metal’s surface that will be processed, then traversed along the paths. heat will be produced via the friction between the rotating shoulder, the tool pin, and the surface of the metal. the metals’ temperature doesn’t reach its point of melting and only plastic-deformations appear in the region of processing. recrystallization placed in the severely distorted metals, because of the homogeneous and refined structure of the grain in the stirred-area [6]. fsp has many benefits. fsp is a short route solid state process which has a single step processing which reaches homogeneity and micro-structural refinement. also, the heat input through fsp come from plastic deformation and friction, and that refers to the fact that fsp is environment-friendly and energy-efficient approach with no radiation, noise and deleterious gas. fsp localizes modifications and controls of micro-structures in the near-surface layers of http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i1.580 2 abbass and sharhan /al-qadisiyah journal for engineering sciences 12 (2019) 001–006 the processed components of the metal [7].the taguchi method has been applied in a large scale to engineering analysis and is widely used in designing systems with high quality to investigate the effect of the fsp factors with using a small number of tests [8]. kwon et al. [9] noticed that after applied fsp on 1050 aluminum alloy mechanical characteristics like hardness and tensile strength improved when decreasing the speed of the tool rotation. at 560rpm, those properties increased due to grain enhancement by nearly 37% and 46% respectively in comparison with the base alloy.elangovan and balasubramanian [10] studied the impact of the parameters of fsp (pin profile and speed of rotation) on aa2219 aluminum alloy has 6mm thickness. using five various tool pin-profiles (tapered cylindrical, straight cylindrical, threaded cylindrical, square and triangular) utilized three various tools rotational speed to manufacture weld. they have discovered that the square tool pin profile mechanically generates sound and metallurgically defects free welds in comparison with other tool pin profiles. shafiei zarghani et al. [11] used the fsp to create very small grained materials via strict plastic deformations. fsp has been performed for extruding 6082-t4 aluminum alloy for producing very small grained micro-structure with a grain of a size between 0.5µm and 3µm. the fsped aluminum alloy hardness considerably increases with the decrease in the speed of tool rotation. elangovan and balasubramanian [12] have proved that the impact of the fsp parameters (speed of rotation and pin profile) on aa6061 aluminum alloy. using 5 various tool pin-profiles (threaded cylindrical, tapered cylindrical, straight cylindrical, square and triangular) utilized 3 different tools rotational speed to manufacture weld. they have discovered that the square pin profiled tool produced mechanical sounds and metallurgically defected free welds in comparison with other tool pin profiles. magdy et al. [13] applied fsp on 6082-t6 aluminum alloy for improving the mechanical properties and modifying the micro-structure. at the fixed speed of rotation (850rpm) and 3 various traverse speeds (90,140,224) mm/min was utilized for processing. strength and hardness increased with the increase of traverse speed, increasing the number of passes resulted in lowering the ultimate tensile strength and softening. the current study aims at obtaining the best parameters of fsp which are the speed of tool rotation, travel speed and a number of passes. the identification of the most effective parameters of friction stir processing is made by using l9 taguchi orthogonal array. furthermore, anova is used to find out how much each parameter contributes to the process. 2. experimental work aluminum alloy plate aa6061-t6 employed in this study. this plate was prepared into dimensions of (150×100×6) mm by using cutting machine. the chemical structure of this alloy has been performed with the use of spectro-meter analysis apparatus that has been presented in the “general company for examination and rehabilitation engineering “, as listed in tables 1. the mechanical properties of the alloy listed in table 2. table1: chemical composition of the as-received aa6061-t6 alloy (weight %) element wt.% si fe cu mn mg cr ni zn ti other al nominal (value) [1] 0.8 max 0.7 max 0.4 max 0.15 max 1.2 max 0.35 max 0.05 max 0.25 max 0.15 max 0.05 max bal. measured (value) 0.636 0.586 0.258 0.105 0.916 0.183 0.0032 0.0357 0.051 0.0147 bal. t6: solution heat treatment and artificial aging. table 2: mechanical properties of aa6061-t6 alloy base alloy aa6061-t6 yield strength ys (mpa) tensile strength ts (mpa) elongation % hardness hv kg/mm2 measured value 160 314 28 58 standard value * 276 310 12 95 *datasheet for asm aerospace specification metals inc. the fsp has been performed on a vertical milling machine (type: wmwheckert-germany). the specimens are prepared and fixed in a specially designed and fabricated fixture and clamped firmly in order to ensure that the plates remain in their places and don’t fly away because of the welding forces as shown in fig. 1 and tool has been plunged into the chosen sheet area. a non-consumable cylindrical-shouldered and threaded pin made of high speed steel (hss) with a shoulder diameter of 16 mm and 6 mm pin diameter of length 3.2 mm has been utilized as shown in fig. 2 and tool tilt angle 2°. 3. orthogonal array selection the experimental design suggested by taguchi covers the use of orthogonal arrays to arrange in order the parameters of fsp and the levels at which they must differ. in terms of the l9 orthogonal array suggested by taguchi, three experiments were carried out on each set of parameters of the process. the three parameters which were used in this work were the speed of rotation (rpm), transverse speeds (mm\min), and a number of passes (1,2 & 3) in same direction. table 3 shows the parameters and levels of the process. the tilt angle (2º) remains constant. a total of ''nine experimental'' runs were made, a set of levels was utilized for each control factor as shown in table 3. figure 1: sample after frictions stir processing figure 2 : the tool used in this work abbass and sharhan /al-qadisiyah journal for engineering sciences 12 (2019) 001–006 3 table 3: parameters and their levels of fsp parameters level 1 level 2 level 3 rotation speed rs (rpm) 800 1000 1250 welding speed ws (mm\min) 16 25 32 number of passes 1 2 3 table 4: experimental results of doe taguchi l9 orthogonal array experiment number rs (rpm) ts (mm/min) no. of passes 1 800 16 1 2 800 25 2 3 800 32 3 4 1000 16 2 5 1000 25 3 6 1000 32 1 7 1250 16 3 8 1250 25 1 9 1250 32 2 after friction stir processing tensile tests have been performed to estimate the tensile strength of fsp at all processing parameters. tensile specimens were cut parallel to the fsp in the longitudinal direction by cnc milling machine type (c-tek). fig. 3 shows the dimensions with the geometry of the tensile sample according to the properties specified in the astm standard e8m011 for specimens of sub-size [14]. figure 3: sample of astme8m sub-size for tensile test, all dimensions in mm 4. microstructure examination and microhardness test an optical microscope was used to examine the specimens which were made from a cross-section of the fsp in sequences steps. the operation of wet grinding was made using water and emery paper of sic in various grits of 320, 500, 600, 800, 1000 and 1200. the process of polishing was made on the samples using 0.5μm diamond paste and special cloth for polishing and lubricant. the process of etching was carried out on the specimens by utilizing etching solution keller's reagent (composed of 95 ml h2o, 2.5 ml hno3, 1.5 ml hcl, 1.0 ml hf). they were washed and dried. optical micro-scope is utilized to supply information concerning the microstructure of processing specimens. digital micro-hardness tester type (laryee, mode hvs-1000) was utilized to conduct the vickers hardness test. a 200 gm load applied cross-section of sz of the fsp direction, for 15 sec. 5. results and discussion 5.1. signal to noise ratio: (s\n) ratio tensile strength is an important property taken into consideration in this study. for the estimation of the fsp parameters impact on tensile strength, values of means and s/n ratio for every one of the direct factors (rotational speed of the tool, travel speed and a number of passes) have been considered. a suitable s/n ratio has been selected utilizing previous knowledge, experience, and process understanding. concerning this study, the s/n ratio has been carefully chosen in terms of the standard of the higher is better, for the sake of maximizing the response. the method of taguchi is utilized for determining the difference of the quality properties from the wanted value is achieved by using the s/n ratio. in this study, the data of tensile strength have been analyzed to decide the influence of fsp parameters. table 5 depicts the 3 levels of parameters of the process as “per l9 orthogonal array”, the means of tensile strength and the matching s/n ratio. analyzing the mean for every experiment will result in better parameter combination level so that tensile strength at a high level is made certain in terms of experimental data. the plots as in figures (4 and 5) may be utilized for identifying the highest level of process parameter conformity to the biggest s/n ratio and tensile strength respectively. the tensile strength is assessed to be the highest with speed of rotation of 1250 rpm and travel speed 32 mm/min and two passes which is optimal from the plots obtained. table 5: tensile strength and s/n ratio for experiments. experiment number rs (rpm) ts (mm\min) no. of passes mean tensile strength mpa s\n ratio 1 800 16 1 162 44.19 2 800 25 2 158 43.97 3 800 32 3 152 43.63 4 1000 16 2 159 44.02 5 1000 25 3 138 42.79 6 1000 32 1 165 44.34 7 1250 16 3 160 44.08 8 1250 25 1 170 44.60 9 1250 32 2 215 46.64 5.2. analysis of variance (anova) this test is applied for studying the significance regarding the fsp’s parameters affecting the tensile strength related to processing with fsp. to determine which one of the processes significantly impact the tensile strength, the f-test which is termed after fisher might be applied. generally, the process parameter’s difference holds a considerable impact on the quality characteristics related to the tensile strength of the processing, in the case when f is considered high. the anova test results indicate that the process’s parameters are very important factors which influence the tensile strength with fsp in the order of a number of passes, travel and rotation speeds. from table 6 it was shown that the anova of tensile result display that the rotation speed is considered as the utmost effective parameter having a percentage of 38.68% after that comes the number of passes 31.9% and travel speed 22.55%. 4 abbass and sharhan /al-qadisiyah journal for engineering sciences 12 (2019) 001–006 figure 4 :main effect plot for s/n ratios figure 5: main effect plot for mean tensile strength table 6: anova for fsp parameters figure 6: the tensile strength of base alloy aa6061-t6 and fsped samples 5.3. tensile test results the tensile results indicated the fact that the tensile strength regarding the base alloy has been greater than that of all friction stir processing tested as shown in fig. 6. according to the test results, the increment in the travel and rotations speeds will lead to an increment in the tensile strength. at a tool rotation speed of (1250 rpm), the tensile strength had its highest value. in comparison to un processing alloy, it has been discovered that the tensile strength will decrease with increased tool rotation speed, the is because of the extra heat that is generated in the stir zone because of the high rotational speed for the tool, and thus increasing stirring influence which is related to the pin, however it could create extra explosion or flash of metal flow outside causing imperfections in stir-zone. similarly, elevated heat inputs will cause an increase in peak temperature and triggers graingrowth, that will cause a reduction in the tensile strength. at fsp speeds of (16mm\min) and (25mm\min), it has been spotted that the tensile strength has been lesser than of speed (32mm\min), this is considered as the result of the elevated frictional heat and dissipation most of the heat created regardless of tool rotations speed as well as the number of passes. the minimum rotational speed leads to decrease the fsp’s tensile strength because of the higher heat input in processing samples, whereas the maximum rotation speed causes an increase in tensile strength which will result in short exposure time to frictional heating. the fsp at two passes has higher tensile strength than that of one or three passes. this is because the fsp at 2 passes created a pronounced effect in refining the stir zone microstructure and the break-up of inter metallic compound. the best value of tensile strength of fsp (215mpa) was achieved at (1250rpm) rotating speed (32 mm/min) rotation speed and two passes. the acquired results are consistent with the results obtained by the researcher magdy et al. [13]. 5.4. microhardness results microhardness distribution along fsp cross section is displayed in fig. 7, vickersmicro-hardness apportionment on cross section vertical to the tool traverse direction regarding the fsp sample formed at a tool rotational speed of 1250 rpm and travel speed32mm/min with two passes. the stirzone showed a higher hardness than the unaffected zone. the maximum hardness was 75hv in center of stir zone. this is due to refining grain and dynamic recrystalline stir zone and presence of precipitates 2nd phase particles of al3mg2 phase in α-al. several researchers [15,16] proved these outcomes in their studies of fsw welding aluminum alloys. figure 7 : microhardness distribution across the transverse cross section of fsp for base metal at rotation speed 1250 rpm, travel speed 32 and two passes parameters df seq ss adj ss adj ms f pa% rotation speed rs (rpm) 2 1368.7 1368.7 684.3 5.64 38.68 travel speed ts(mm/min) 2 798.0 798.0 399.0 3.29 22.55 number of passes 2 1128.7 1128.7 564.3 4.65 31.9 error 2 242.7 242.7 121.3 6.87 total 100% abbass and sharhan /al-qadisiyah journal for engineering sciences 12 (2019) 001–006 5 5.5. microstructure results fig. 8 (a,b,c &d) shows the microstructural characterization of a cross section of friction stir processing at best parameters (1250 rpm,32mm/min and 2 passes). it is seen that the fsp sample has four distinct regions: stir zone (sz) is the region that is thermo-mechanically processed zone where the grain size is very fine and equaxed grains or homogenized structure (fig. 8a), friction stir processed zone (fsp zone) (fig. 8c), the thermo mechanically affected-zone (tmaz) in which the grain is elongated due to the fact that it has been deformed in a thermomechanical way with observation of union rings (fig. 8b), heat affected-zone (haz) which is considered to have the same grain structure of base metal (bm) and the base metal or aa6061-t6 alloy (unaffected metal ) considered as the region which is not influenced through the fsp process. this microstructure contains very fine precipitates 2nd phase particles of al3mg2 phase distributed uniformly in α-al.( fig. 8d). 6. conclusions  it was found that optimum or best friction stir processing (fsp) parameters were 1250 rpm of rotation speed, 32mm/min of travel speed and two passes for a number of passes.  tensile strength of fsp ed sample increases as the rotation speed and travel speed increase.  it has been indicated that the stir zone of fsp exhibited microhardness higher than tmaz and haz because of grain refinement and existence of precipitates (al3mg2) distributed in the aluminum matrix.  it was shown from anova analysis of tensile strength that the rotation speed has contribution percentage (38.68% ) which is the most effective parameter followed by a number of passes was 31.9% and then travel speed was 22.55 %. figure 8: microstructure of friction stir processed ( fsp ) sample at optimum conditions 1250 rpm , 32mm/min and 2 pass in same direction at 100x. (a) sz and tmaz , (b) union rings in tmaz , (c) fsp zone , (d) base alloy aa6061-t6. references [1] c. saravanan, k. subramanian, v.a. krishnan, r.s. narayanan, effect of particulate reinforced aluminium metal matrix composite–a review, mechanics and mechanical engineering, 19(1) (2015) 23-30. [2] v. kishan, a. devaraju, k.p. lakshmi, influence of volume percentage of nanotib2 particles on tribological & mechanical behaviour of 6061-t6 al alloy nano-surface composite layer prepared via friction stir process, defence technology, 13(1) (2017) 16-21. [3] g. venkateswarlu, m.j. davidson, p. sammaiah, effect of friction stir processing process parameters on the mechanical properties of az31b mg alloy, manufacturing and industrial engineering, 13(1-2) (2014). [4] n.m. daniolos, d.i. pantelis, p.i. sarafoglou, aa7075 /al2o3 surface composite materials fabrication using friction stir processing, in: 2nd international conference of engineering against fracture (iceaf ii), mykonos, greece, 2011. [5] d. deepak, r.s. sidhu, v. gupta, preparation of 5083 al-sic surface composite by friction stir processing and its mechanical characterization, sz tmaz fsp zone a b c d c d 6 abbass and sharhan /al-qadisiyah journal for engineering sciences 12 (2019) 001–006 international journal of mechanical engineering, 3(1) (2013) 1-11. [6] q. liu, l. ke, f. liu, c. huang, l. xing, microstructure and mechanical property of multi-walled carbon nanotubes reinforced aluminum matrix composites fabricated by friction stir processing, materials & design, 45 (2013) 343-348. [7] z. ma, friction stir processing technology: a review, metallurgical and materials transactions a, 39(3) (2008) 642-658. [8] s.k. karna, d.r.v. singh, d.r. sahai, application of taguchi method in indian industry, international journal of emerging technology and advanced engineering, 2(11) (2012) 387-391. [9] y. kwon, i. shigematsu, n. saito, mechanical properties of fine-grained aluminum alloy produced by friction stir process, scripta materialia, 49(8) (2003) 785-789. [10] k. elangovan, v. balasubramanian, influences of pin profile and rotational speed of the tool on the formation of friction stir processing zone in aa2219 aluminium alloy, materials science and engineering: a, 459(1-2) (2007) 718. [11] a. shafiei zarghani, s. kashani bozorg, a. zarei-hanzaki, ultrafine grained 6082 aluminum alloy fabricated by friction stir processing, international journal of modern physics b, 22(18n19) (2008) 2874-2878. [12] k. elangovan, v. balasubramanian, influences of tool pin profile and tool shoulder diameter on the formation of friction stir processing zone in aa6061 aluminium alloy, materials & design, 29(2) (2008) 362-373. [13] m.m. el-rayes, e.a. el-danaf, the influence of multi-pass friction stir processing on the microstructural and mechanical properties of aluminum alloy 6082, journal of materials processing technology, 212(5) (2012) 1157-1168. [14] n. yuvaraj, s. aravindan, fabrication of al5083/b4c surface composite by friction stir processing and its tribological characterization, journal of materials research and technology, 4(4) (2015) 398-410. [15] m.k. abbass, h.h. abd, a comparison study of mechanical properties between friction stirwelding and tig welded joints of aluminum alloy (al 6061-t6), engineering and technology journal, 31(14 part (a) engineering) (2013) 2701-2715. [16] m.k. abbass, k.m. raheef, effect of we lding parameters on mechanical properties of friction stir lap welded joints for similar aluminum alloys (aa1100-h112 & aa6061-t6), journal of engineering and sustainable development, 22(2) (2018) 60-71. [17] w. rashid, effect of some factors in the friction stir welding on tensile strength of al-zn-mg alloy, alqadisiyah journal for engineering sciences, 8(3) (2015) 398-409. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 189 a comparative study on the thermal conductivity of micro and nano fluids by using silver and zirconium oxide layth w. ismael dr. khalid faisal. sultan lecturer lecturer materials . eng. dept. electromechanical. eng. dept. university of technology university of technology ph. .d. student – ozyegin university e-mail: alfahadlwi@yahoo.com e-mail: ksultan61@yahoo.com received 12 november 2012 accepted 17 march 2014 abstract in this article experimentally investigations have been carried out to study the effect of the size and type particles on the thermal conductivity of micro and nanofluids. the study investigated nanofluids and microfluids which containing silver (ag) and zirconium oxide (zr2o3) as well as in the size and type of micro and nanoparticles in distilled water as base fluid with different particles size and concentrations. the experimental results emphasized the enhancement of the thermal conductivity due to the nanoparticles presence in the fluid greater than microfluids, also shown the effect of the particle size and concentration on the thermal conductivity. it has been recognized that the addition of highly conductive particles can significantly increase the thermal conductivity of heat – transfer fluids. particles in the micro and nano – size range have attracted the most interest because of their enhanced stability against sedimentation and, as a result, reduction in potential for clogging a flow system. furthermore the results showed that, the obtained thermal conductivities doubtlessly revealed that size and type particles was a key factor affecting conductive heat transport in suspensions. the aim of this article is an experimental exploration of the thermal conductivity of micro – and nano – particles and compared with them as well as type particles and the method used in this researcher know lee's disc technique. these results show noticeable enhancement in the thermal conductivity were evaluated to be ( 7.66 %, 2.35 %) for the ag, zr2o3 – distilled water nanofluid while reaches to (3.23 %,1.02 %) for the ag , zr2o3 – distilled water micro fluids at the concentration of (0.05 vol. %) and at the room temperature. a good agreement was found between the experimental obtained data for this paper and other results from published papers. mailto:alfahadlwi@yahoo.com mailto:ksultan61@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 190 وأوكسيد الفضة باستخدام والنانوية المايكروية للموائع الحراري التوصيل بين مقارنة دراسة الزركونيوم فيصل سلطان د. خالد ليث وضاح اسماعيلمدرس الكهرو ميكانيكيةقسم الهندسة قسم هندسة المواد الجامعة التكنولوجية الجامعة التكنولوجية الخالصة يتضمن البحث الحالي دراسة عملية للموصلية الحرارية للموائع التي تحتوي على حبيبات نانوية وما يكروية مخلوطة مع المائع الزركونيوم وأوكسيد ag فضة وكذلك تأثير حجم ونوع الجزئيات. الدراسة تضمنت سوائل نانوية وما يكروية مكونة من االساسي zr2o3 على شكل حبيبات نانوية وما يكروية مختلطة مع الماء النقي كمائع اساسي بكسور حجمية وتراكيز مختلفة. أكدت النتائج التجريبية تحسين الموصلية الحرارية بسبب وجود الجسيمات النانوية في المائع أكبر من الموائع الميكروية ، أظهرت أيضا تأثير حجم يمكن أن تزيد بشكل كبير من الموصلية ا لحرارية وصيل الحراري. وقد تم االعتراف بأن إضافة جزيئاتالجزيئات والتركيز على الت في انتقال الحرارة بالموائع . الجزيئات ذات الحجم النانوي والميكروي اجتذبت قدر كبير من االهتمام بسبب تحسين األستقرارية ضد دفق بالنظام وعالوة على ذلك أظهرت النتائج أن التوصيالت الحرارية التي تم الحصول الترسيب وبالنتيجة ،الحد من احتمال انسداد الت عليها كشفت بال شك أن حجم و نوع الجزيئات كان عامال رئيسيا يؤثر على انتقال الحرارة بالتوصيل في الموائع الميكروية والنانوية . رية للجزئيات النانوية والميكروية و بالمقارنة بينهما ، فضال عن نوع الهدف من هذه المقالة هو دراسة عملية في الموصلية الحرا الجزيئات و الطريقة المستخدمة في هذا الباحث تعرف بتقنية قرص لي. كما بينت النتائج العملية تحسن ملحوظ في الموصلية الحرارية بسبب الحبيبات الما يكروية والنانوية المضافة الى المائع، كذلك ر بينت تأثير الحجم الحبيبي والتركيز على الموصلية الحرارية. النتائج بينت ايضا ان الموصلية الحرارية الى المواد النانوية تكون اكب من الموصلية الحرارية للمواد المايكروية بسب صغر حجم الجزئيات النانوية بالمقارنة مع الحجم المايكروية. وان نسب التحسين في مع الماء النقي على التوالي zr2o3 الزركونيومأوكسيد و agالى المائع النانوي الفضة (%2.73,7.66)الحرارية كانت الموصلية وبتركيز مع الماء النقي zr2o3 الزركونيومأوكسيد و agالى المائع المايكروية الفضة (%3.23 ,1.02). بينما كانت هذه النسب وبدرجة حرارة الغرفة. وجد توافق جيد بين النتائج العملية المستحصلة من هذه الدراسة ونتائج اخرى في بحوث منشورة (0.05%) سابقة. keywords: nano fluid, micro fluid, thermal conductivity, enhancement. nomenclature d thickness of the discs mm ds thickness of the sample mm e heat loss watt i current a v voltage v k thermal conductivity w/m 2 .k al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 191 n empirical shape factor __ r the radius of the disc mm t1, t2, t3 the temperatures of the through discs. k ф volume fraction % subscripts nf nanofluid __ p nanoparticles __ b base __ 1introduction heat transfer fluids can exhibit significant increases in thermal conductivity with the addition of highly conductive particles. recent attention has focused on micro – and nano – particle suspensions because of their enhanced stability against sedimentation, reduction in potential for clogging a flow system, as well as the tantalizing possibility of unexpected enhancements in thermal conductivity. the later has been spurred by reports of large increases in the thermal conductivity in very – low – volume fraction nanoparticle (up to 100 nm in size) suspensions. for instance, the effective thermal conductivity of an ethylene-glycol-based nanofluid containing copper nanoparticles with diameters less than 10 nm was reported to increase by up to 40% at 0.3% vol of dispersed particles [1]. another example is silver nanoparticles in water and toluene[2], where thermal conductivity enhancement of 521% was observed at a loading of only 0.026% vol. the addition of less conductive aluminum oxide particles were reported to increase the resulting thermal conductivities of base fluids by up to 30% at particle volume fraction of al2o3 of 5% [3], [4], 4% [5] or 3% [6]. in each case, the enhancements in thermal conductivity were reported to be greater than predicted by macroscopic theory for the given particle volume fraction and thermal conductivity. among nanoparticle suspensions, those containing carbon nanotubes (cnts) have attracted some of the most interest. discovered in 1991, carbon nanotubes have already entered the realm of practicality, finding use in the aerospace, automotive and telecommunications industries because of their interesting characteristics. single – walled carbon nanotubes are 100 times stronger than steel at one-sixth the weight, and their thermal conductivity is about 5 – 10 times greater than that of very conductive materials like aluminum or copper. nanotubes can be electrical conductors or semiconductors depending on their crystal structure. moreover, many physical properties of nanotubes, including their thermal conductivity, are expected to be highly anisotropic. one of the emerging miniaturization techniques is the nanofluid technology which meets the shortcomings of the earlier used bulk fluids and conventional base fluids. nanofluids exhibit large thermal conductivity compare to traditional (base) fluids and are suitable for heat transfer applications choi et al. [7]; das et al. [8]; murshed et al. [9]; xuan and li [10]. there is a great attraction towards al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 192 nanofluids because they are proved to be far more superior when compared to the conventional bulk fluids. nanofluids offer promising heat transfer applications which is of major importance to industrial sectors including transportation, power generation, micro-manufacturing, electronics, engines, thermal therapy, heating, cooling, ventilation and air conditioning. many of the reported anomalous enhancements in thermal conductivities in nanofluids were non – reproducible keblinski et al. [11]. recent experimental studies suggest that nanofluids exhibit thermal conductivity enhancement within maxwell’s limit (philip et al. [12]; timofeeva et al. [13]; eapen et al. [14];shima et al. [15]. zhang et al. [16]) measured the effective conductivity and thermal diffusivity of au/totuene, al2o3/water, tio2/water, cuo/water nanofluids using the transient short-hot-wire (shw) technique, which was developed from the conventional transient hot wire (thw) technique and is based on the numerical solution of two dimensional transient heat conduction for a short wire with the same lengthto-diameter ratio and boundary conditions as those used in the actual measurements. the diameters of au, al2o3, tio2 and cuo spherical particles were 1.65, 20, 40 and 33nm, respectively. the effective thermal conductivities of the nanofluids show no anomalous enhancement and can be predicted accurately by the equations of the hamilton and crosser model. liu et al. [17] measured the thermal conductivities of nanofluids containing cnts n dispersed in ethylene glycol and a synthetic engine oil. the increase of thermal conductivity is up to 12.4% for cnt – ethylene glycol suspensions at 1.0 vol% and 30% for cnt – synthetic engine oil suspensions at 2 vol%. one possible reason for this is that the thermal conductivity is highly dependent on important factors such as the structure of the cnts, clustering, temperature, etc. further systematic research is necessary to obtain a whole map for the thermal conductivities of cnts. hwang et al. [18] compared the thermal conductivity of four kinds of nanofluids such as mwcnts in water, cuo in water, sio2 in water, and cuo in ethylene glycol. they found that the thermal conductivity of mwcnt nanofluid was increased up to 11.3% at 1 vol%, which is relatively higher than that of the other groups of nanofluids .zhang et al. [16] investigated the effective thermal conductivity and thermal diffusivity of cnt/water nanofluids using the transient short – hot – wire technique. the average length and diameter of cnts are 10 μm and 150 nm, respectively. however, the measured results demonstrate that the effective thermal conductivities of the nanofluids show no anomalous enhancements and can be predicted accurately by the unit – cell model equation of yamada and ota [19] for carbon nanofibers. there are few studies made on ultrasonic propagation in magnetic nanofluids by some researchers (sayan and ulrich [20]; motozawa et al,[21]; raj et al. [22]) no systematic research efforts have been carried out to compare the behavior of micro and nanofluids in terms of acoustical and thermal parameters. the fundamental understanding of exact mechanisms responsible for the anomalous values of ultrasonic wave propagation is unclear because of the lack of molecular level understanding of the ultrafine particles (raj et al. [22]) that warrant systematic studies. a systematic study on the micro and nanofluids is required for the basic understanding of how the nanoparticles behave in fluids. the objective of this work is an experimental exploration of the thermal conductivity of micro – and nano – particle and compared thermal conductivity increase in suspensions containing micro – and nano – sized particles as well as study the type and particles agglomeration effect on the thermal conductivity of micro and nanoparticle suspensions. 2-theoretical formulation currently, there is no reliable theory to predict the anomalous thermal conductivity of nanofluids. from the experimental results of many researchers, it is known that the thermal conductivity of nanofluids depends on parameters including the thermal conductivity of the base fluid and the al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 193 nanoparticles , the volume fraction, the surface area, and the shape of the nanoparticles , and the temperature. there are no theoretical formulas currently available to predict the thermal conductivity of nanofluids satisfactorily. for particle – fluid mixtures, numerous theoretical studies have been conducted dating back to the classical work of maxwell. yu and choi [23] proposed a modified maxwell considering to account the effect of the nano-layer by replacing the thermal conductivity of solid particles kp in eq. (1) with the modified thermal conductivity of particles kp, which is based on the so called effective medium theory.     b k φ 3 β1 b k p k2 b 2k p k φ 3 β1 b k p k2 p 2k p k nf k                            ……………………………………………..…….(1) where kp is the thermal conductivity of the particle, kb is the thermal conductivity of the base fluid and is the particle volume fraction in the suspension the thermal conductivity of the nanofluid is calculated from hamilton& crosser [24] using the following equation:       b k φ p k b k b k1 p k φ p k b k1 b k1 p k nf k                n nn …………………………………………………..(2) where: knf is the thermal conductivity of the nanofluid, kp is the thermal conductivity of the nanoparticles , kb is the thermal conductivity of the base fluid furthermore, the thermal conductivity of the nanofluid is calculated from wesley charles –williams [25]. 1vol%) (t)(4.5503 b k nf k  …………………………………………………………………(3) one well – known formula for calculating the thermal conductivity of nanofluid is timo feera et al. [13]. b )k3(1 nf k  …………………………………………………………………………….……(4) al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 194 3-experimental investigation 3.1-sample preparation nanofluid samples were prepared by dispersing pre – weighed quantities of dry particles in distilled water. the ph of each aqueous mixture was measured, the mixtures were then subjected to ultrasonic mixing (sonics &materials, inc. vibra cell vcx 750) for one hour to break up any particle aggregates. the acidic ph is much less than the iso electric point of these particles (6 – 8 for zirconium oxide and 5.5 – 8 for silver), thus ensuring a positive surface charge on the particles. the surface charge enhanced repulsion between the particles, which resulted in uniform dispersions for the duration of the experiments. fig.(1) depicted an aqueous nanofluids oxide (zr2o3) and silver (ag). the same preparation for micofluids and fig.(2) shows an aqueous micofluids oxide (zr2o3) and silver (ag). (a) (b) figure (1): aqueous nanofluids (a) containing zirconium oxide(zr2o3) and (b) containing silver (ag) nanoparticles al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 195 (a) (b) figure (2): aqueous micro fluids (a) containing zirconium oxide(zr2o3) and (b) containing silver (ag) micro particles 3.2-thermal conductivity measurement since thermal conductivity is the most important parameter responsible for enhanced heat transfer many experimental works been reported on this aspect. lee's disc technique was used for the measurement of the thermal conductivity for nanofluids and microfluds. the apparatus which is used in the measurement of the thermal conductivity is shown in the figs.(3 and 4). figs.(3) reveal the built – up cell which is used to measure the thermal conductivity, the cell contains three parts, on the two sides of the cell there is two copper discs (1 and 2) as shown in the figure. while the third part of the cell located between the two copper discs and contains the experimental fluid. fig.(4) represents the test apparatus (lee's disc apparatus) type (griffin and george) with tested sample disc and some accessories to measure the temperature on both sides of the sample disc in order to calculate the thermal conductivity, the heater is switch on from the power supply with(v = 6 v and i = 0.2 a) to heat the copper discs ( 2 and 3) and the temperature of the all discs increases in nonlinear relationships and at different rates with the time according to its position from the heat source, and the temperatures were recorded every (5 minutes) until reach to the equilibrium temperature of all discs. then the thermal conductivity can be calculated by using the following form murthy et al [26] and rondeauz & bready [27]:                       2 tds 2 1 1 tds 2 1 1 d r 2 1 te ds 1 t 2 t k ……………………………………………….(5) and can calculate the value of e as follows:            3 t 3 d 2 t 2 d 2 t 1 tds 2 1 1 t 1 derπ2 3 t 1 te 2 rπiv …………………………..(6) al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 196 the experimental results for the thermal conductivity were compared with the equations or models of thermal conductivity developed by researchers such as yu and chio model [23], hamilton & crosser model [24], wesley charles – williams model [25] and timo feeva et al model [13], figure (3): testing cell figure (4): thermal conductivity test apparatus 4-results and discussion in order to verify the accuracy and the reliability of the experimental apparatus , the thermal conductivity are experimentally measured for distilled water ethylene glycol ethanol before obtaining those of micro and nanofluids (ag+ dw) , (zr3o2+ dw). fig.5 shows the variation of theoretical values with experimental values for thermal conductivity to three types of fluids (distilled water, ethylene glycol, methanol, ethanol). as it is seen from this figure, the deviation of the experimental data from the theoretical less than 5%. figs. (6 and 7) show that the ratio of the thermal conductivity ( k nano/ k base) increases significantly with the increasing of concentration, and the relation between the thermal conductivity with the concentration is a leaner relation. the enhancement in the thermal conductivity were evaluated to be ( 7.66%,2.35%) for the ag, zr2o3 – distilled water nanofluid while reaches to (3.23%,1.02%) for the ag, zr2o3 – distilled water micro fluids at the concentration of (0.05 vol. %). the results obtained from these figures indicate that the silver particles have thermal conductivity higher than that of the zirconium oxide particles. the experimental results for this investigation were compared with other data from published papers at the same field, very good agreement was found between the experimental data and model r.l. hamilton, o.k. crosser [11], is the closest to practical by difference does not exceed 1.25%. thermal conductivity was increased for the nanofluids and microfluids which contains large particle size compared with that contains small particle size as shown in figs. (8 and 9), these figures show the effect of the particle size on the thermal conductivity. figs. (10 and 11) shows a comparison between the experimental data for thermal conductivity of (ag , zr2o3 – distilled water ) nanofluids and micro fluids at (dp= 20, 30, 50 nm and 20, 30, 50 µm) particle size, this comparison shows the enhancement of the thermal conductivity for the two types of nanofluids are greater than two types of microfluids (ag , zr2o3 – distilled water ) and the effect of the particle size on this enhancement. it has been tt t al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 197 recognized that the addition of highly conductive particles can significantly increase the thermal conductivity of heat – transfer fluids. particles in the microand nano – size range have attracted the most interest because of their enhanced stability against sedimentation and, as a result, reduction in potential for clogging a flow system . furthermore the results showed that, the obtained thermal conductivities doubtlessly revealed that size and type particles was a key factor affecting conductive heat transport in suspensions. for nanofluids, despite the promise of enhanced stability due to the nanoscale size of particles, particle agglomeration state can have a profound effect on the resulting thermal conductivity of the suspension. figs.(12) and (13) reveal the experimental data of thermal conductivity to nanofluids and microfluids for two types of particles ag , zr2o3 – distilled water. these figs indicated that thermal conductivity of nanofluids are greater than thermal conductivity of microfluids due to the small nano scale for nanoparticles. 5-conclusion the present work has reached to the following conclusions: 1. thermal conductivity increases with the increasing the concentration of nanofluids and microfluids. 2. thermal conductivity increases with the increasing of the particle size which presence in the base fluids for the nanofluids and microfluids. 3. nano and micro particle type (material type) plays an important act in the thermal conductivity enhancement. 4. thermal conductivity by using metallic such as (ag) is greater than nonmetallic (zr2o3) for nano and microfluids. 5. the nano and micro particles size was a key factor affecting conductive heat transport in suspensions. references [1] eastman, j. a., choi, s. u. s., li, s., yu, w., and thompson, l. j., 2001, “anomalously increased effective thermal conductivities of ethylene glycol based nanofluids containing copper nanoparticles,” appl. phys. lett., 78(6), pp.718–720. [2] patel, h. e., das, s. k., sundararajan, t., sreekumaran, n. a., george, b., and pradeep, t., 2003, “thermal conductivities of naked and monolayer protected metal nanoparticle based nanofluids: manifestation of anomalous enhancement and chemical effects,” appl. phys. lett., 83(14), pp. 2931– 2933. [3] xie, h., wang, j., xi, t., liu, y., ai, f., and wu, q., 2002, “thermal conductivity enhancement of suspensions containing nanosized alumina particles,” j. appl.phys., 91(7), pp. 4568–4672. [4] xie, h., wang, j., xi, t., liu, y., and ai, f., 2002, “dependence of the thermal conductivity of nanoparticle-fluid mixture on the base fluid,” j. mater. sci. lett.,21(19), pp. 1469–1471. [5] das, s. k., putra, n., thiesen, p., and roetzel,w., 2003, “temperature dependence of thermal conductivity enhancement for nanofluids,” j. heat transf., 125, pp.567–574. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 198 [6] lee, s., choi, s., li, s., and eastman, j. a., 1999, “measuring thermal conductivity of fluids containing oxide nanoparticles,” j. heat transf., 121(2), pp. 280–289. [7] choi sus, zhang zg, yu w, lockwood fe, grukle ea anomalous thermal conductivity enhancement in nano-tube suspensions. appl phys lett 79: (2001) 2252–2254. [8] das sk, putra n, thiesen p, roetzel w :temperature dependence of thermal conductivity enhancement for nanofluids. j heat transfer 125: (2003) ,567–574. [9] murshed sms, leong kc, yang c enhanced thermal conductivity of tio2–water based nanofluids. int j therm sci 44: (2005) ,367–373. [10] xuan y, li q ,heat transfer enhancement of nanofluids. int j heat fluid flow 21: (2000) ,58–64. [11] keblinski p, eastman ja, cahill dg ,nanofluid for thermal transport. mater today 8: (2005) ,36– 44. [12] philip j, shima pd, raj b ,experimental evidence for enhancement of thermal conductivity under clustering. appl phys lett 91: (2007) ,203108. [13] timofeeva ev, gavrilov an, mccloskey jm, tolmachev yv ,thermal conductivity and particle agglomeration in alumina anofluids: experiment and theory. phys rev e 76: (2007),061203-1–061203 – 16 . [14] eapen j, williams wc, buongiorno j, hu l, yip s, rusconi r, piazza r mean-field versus microconvection effects in nanofluid thermal conduction. phys rev lett 99: (2007) 095901. [15] shima pd, philip j, raj b role of micro convection induced by brownian motion of nanoparticles in the enhanced thermal conductivity of stable nanofluids. appl phys lett 94: (2009) ,223101. [16] zhang, x., gu, h., and fujii, m. effective thermal conductivity and thermal diffusivity of nanofluids containing spherical and cylindrical nanoparticles. experimental thermal and fluid science, 31,no. 6, 593–599 (2007). [17] li, x., zhu, d., and wang, x. evaluation on dispersion behavior of the aqueous copper nano suspensions. journal of colloid and interface science, 310, no. 2, 456–463 (2007). [18] hwang, y. j., ahn, y. c., shin, h. s., lee, c. g., kim, g. t., park, h. s., and lee, j. k. investigation on characteristics of thermal conductivity enhancement of nanofluids. current applied physics, 6, no. 6, 1068–1071 (2005). [19] yamada, e. and ota, t. effective thermal conductivity of dispersed materials. wärme – und stoffübertragung, 13, 27 – 37 (1980). al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 199 [20] sayan p, ulrich j the effect of particle size and suspension density on the measurement of ultrasonic velocity in aqueous solutions. chem ,eng process 41: (2002) ,281–287. [21] motozawa m, iizuka y, sawada t ,experimental measurements of ultrasonic propagation velocity and attenuation in a magnetic fluid. j phys condens matter 20:204117. doi:10.1088/0953 – 8984 /20/20/204117,(2008). [22] raj b, philip j, rajkumar kv, kalyanasundaram p ,effect of magnetic field on ultrasonic velocity in a magnetic nanofluid. proc indian natl sci acad 72: (2006) 145–151. [23] w. yu, s.u.s. choi, "the role of interfacial layers in the enhanced thermal of nano fluids: a renovated maxwell model", journal of nano particle research 5 (1–2) (2003) 167–171. [24] r.l. hamilton, o.k. crosser, "thermal conductivity of heterogeneous two component systems", i&ec fundam 1 (1962) 182–191. [25] wesley charles williams, 2006, "experimental and theoretical investigation of transport phenomena in nano particle colloids (nano fluids)", department of nuclear science and engineer at massachusetts institute of technology. [26] murthy bsr, dr. a. ram krisnna and rama krisnna b. v., 2004.thermally analysis of epoxy based fiber reinforced" ie (i) journal –mc, vol.84. [27] rondeauz f. ph., bready j. m. rey. 2001, "thermal conductivity measurement of epoxy system at low temperature", cryogen tic engineering conference (cfc). usa. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 200 figure (5): thermal conductive calibration results figure.(5) thermal conductive calibration results figure (6): thermal conductivity ratio of distilled water – based ag nanofluid al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 201 figure (7): thermal conductivity ratio of distilled water – based zr2o3 nanofluid figure (8): thermal conductivity ratio of distilled water – based ag nanofluid with different particles diameter al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 202 figure (9): thermal conductivity ratio of distilled water – based zr2o3 nanofluid with different particles diameter figure (10): experimental data for thermal conductivity of nanofluids versus particle size al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 203 figure (12): experimental data for thermal conductivity of microfluids versus particle size figure (11): experimental data for thermal conductivity of micro fluids versus particle size al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 204 figure (13): experimental dat for thermal conductivity of microfluid (ag – dw ) and nanofluid (ag – dw ) for different particle size figure (14): experimental dat for thermal conductivity of microfluid (zr2o3 – dw ) and nanofluid (zr2o3– dw ) for different particle size al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 83 investigation the punching shear behavior of reinforced concrete slab-column connection using carbon fiber reinforced polymers dr. ali hameed naser al-mamoori college of engineering, civil engineering department, university of karbala email address: alihameedn@@yahoo.com received 17 october 2014 accepted 18 december 2014 abstract the region of a slab in the vicinity of a support could fail in shear by developing a failure surface in the form a truncated cone or pyramid. this type of failure, called "punching shear failure", is usually the source of collapse of flat-plate and flat-slab structures. an experiment to be conducting to investigate the punching shear strength and failure behavior of self concrete (scc) slabs using carbon fiber reinforced polymer (cfrp) bars as internal strengthening in connection region for slab-column. seven interior slab-column connections tested including same concrete compressive strength and ratio of the reinforcement. all slabs will be tested as a simply supported and subjected to punching loading by interior column. test results show that the internal strengthening technique by using high tensile strength cfrp bars improves the bearing capacity of rc two-way slabs. based on the experimental results, it is possible to increase punching shear capacity by using internally reinforced with cfrp bars concentrated in slab-column zone, this increase is about (33100%) compared with the unstrengthened (control) slab. the effectiveness of the cfrp bars is depended substantially on distributed or arrangement manner in slab-column region. also, it is found that, the use of nsm cfrp bars is an effective technique to enhance shear capacity of scc slab-column models and nearly provided the same efficiency of internal reinforcement. even efficient to increase the punching shear load, the top reinforcement of cfrp bars will not change the brittle-type punching shear failure mode compared with bottom cfrp bars reinforcement. key words: carbon fiber reinforced polymer (cfrp) bars, punching shear behavior, slab-column connection, self compacting concrete (scc), and near surface mounted (nsm) technique. 1introduction slabs-columns or flat plates, are solid concrete slabs of uniform depths that transfer loads directly to the supporting columns without the aid of beams or capitals or drop panels (mccormac and brown, 2014) (1). flat plates are probably the most commonly used slab system today for multistory reinforced concrete hotels, motels, apartment houses, hospitals, and dormitories (varghese, 2009) (2) . the greatest disadvantage of flat plate systems is the risk of brittle punching failure at the slabcolumn connection due to transfer of shear and unbalanced moments (zaghlal, 2009). (3) although, the punching shear capacity of reinforced concrete flat plates can be increased by various means, their applicability is often limited, e.g., traditional shear reinforcing by means of stirrups is al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 83 applicable only to slabs with the depth greater than 150 mm according to (aci committee 31811) (4) . reinforcement using headed studs but this one need much time for construction, etc. ( feretzakis) (5) . recently a new technique using of straight fiber reinforced polymer (frp) bars to improve punching shear resistance and performance of the slab-column connections by internal strengthening; because a high strength to specific weight ratios of frp bars reduce the complicated and heavily reinforced in slab-column connection in comparison with conventional reinforcement to perform the same strength, constructed quickly because of their simple formwork and reinforcing bar arrangements to save in construction time and they give the most flexibility in the arrangement of columns and partitions; therefore, thinner concrete slabs can be obtained. in recent years, the design of modern reinforced concrete structures has become more advanced, the designed shapes of structures are becoming increasingly complicated and heavily reinforced, at the time, and there is a shortage of skilled labor especially at construction sites. furthermore, there is a need to save in construction time and dead load for foundations and also to eliminate problems associated with vibration. therefore, the newly born self compacting concrete (scc) as an innovative building material will offer new possibilities and prospects (al-shammary) (6) . also, it has been used under trade names, such as the non-vibrated concrete (nvc), super quality concrete (sqc) (al-mishhadaniand al-rubaie, 2009) (7) . it is a new type of high performance concrete with the ability of flowing under its own weight and without the need of vibrations (druta, 2003) (8) . okamura and ozawa employed the following methods to achieve self-compactability : (1) limited aggregate content; (2) low water/powder ratio and (3) the use of superplasticizer (okamura and ouchi, 2003) (9) . 2objective of research this paper presents an experimental study on the effect of internal strengthening by straight carbon fiber reinforced polymer (cfrp) bars on the punching shear resistance and overall behavior of slabcolumn systems and a new strengthening technique named near surface mounted (nsm) in two directions of slab under static loads. the basic objective of the present work is to study the fresh and some mechanical properties of scc which will use in casting slab-column connection monolithically . also, to study the effect of the length, location, arrangement or distribution of straight carbon fiber reinforced polymer (cfrp) bars and focusing this reinforcement in critical region; by using the same ratio of cfrp bars. 3experimental program 3-1 description of specimens seven flat plate slabs, are constructed for this study using self compacting concrete (scc) for a square slab (1100×1100 mm) in size, with a total thickness of (60mm) and (120×120mm) square column with (150mm) height, cast monolithically at the centre of the slab. the slab portion of these models is reinforced with bottom reinforced of deformed steel bar of (6mm) diameter distributed across the section (100mm c/c) in two directions. all slabs of geometrically and steel reinforcement are similar. the slabs are simply supported along all edges and the distance from c/c of support is (950mm) and loaded through a central column. figure (1) illustrates all details of geometry and reinforcement scheme of the tested models one control model (cs) without carbon fiber reinforced polymer (cfrp) bars as in figure (1) for comparison with others modes. while others models containing same amount of cfrp bars of 6mm diameter are listed below in table (1) and shown in figure (2). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 04 the specimen (sruf1-nsm) is strengthening by using nsm technique which described according to the recommendation of (aci 440.2r-08) (10) : ply wood strips with a size of 10mm width and 20mm depth were installed at the bottom of the wooden mould to provide two similar grooves in two directions before casting. the slabs were cured in air-conditioned laboratory for 28 days and then the ply wood strips were removed; the grooves were removed of any dirt by blowing. the grooves are then filled halfway with epoxy paste then cfrp bars is placed in the groove lightly pressed so induced the epoxy penetration around the bars then filled with more epoxy and the surface is leveled. the epoxy paste is allowed to cure for at least 7 days before the slabs are tested; figure (3) show the mould and the sruf1-nsm model. 3-2 material properties 3-2-1 cement ordinary portland cement (opc) (type i) was used in this study. the cement was produced by united cement company (ucc) commercially known as "tasluja-bazian". the table (2) shows physical properties and chemical analysis of this cement, which comply with the iraqi standards (iqs) no.5:1984 (11) requirements. 3-2-2 fine aggregate natural sand brought from al-ukhaider region was used in this study. the results conformed to the iqs no.5:1984 zone 2 (12) showed that the physical and chemical properties and the grading are listed in table (3) and table (4); respectively. 3-2-3 coarse aggregate rounded coarse aggregate of maximum aggregate size of 9.5 mm from al-nebai quarry are used. table (5) show the grading of this aggregate, which conforms to the iraqi specification no.45/1984 (12) . the physical and chemical properties are illustrated in table (6). 3-2-4 mineral admixture (silica fume) silica fume used in this study was egypt production under trade name (sika fume®-hr). the physical and chemical properties of silica fume used are shown in table (7), it was conformed to the requirements of (astm c1240-05) (13) . 3-2-5 superplasticizer the superplasticizer used in this study was a glenium 51 (high range water-reducing concrete admixture). it is conformed to (astm c494-05) (14) ; in order to achieve flowability with silica fume to produce scc. table (8) shows the typical properties of glenium 51according to manufacturer. 3-2-6 water tap water was used for both mixing and curing of concrete in this work. 3-2-7 steel reinforcement deformed steel bars (6) mm in diameter are used in this study. it was obtained from brc turkish production. three specimens of each bar are tested under tension according to (astm a615/a615m-05a) (15) requirements. the results of testing steel reinforcement are summarized in table (9). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 04 3-2-8 carbon fiber reinforced polymer (cfrp) bars aslan 201 cfrp bar of 6 mm nominal diameter is used for nsm technique. the certificate of analysis for the physical properties was provided by the manufacturer, (hughes brothers) (16) , as shown in table (10). 3-2-9 epoxy adhesive the epoxy adhesive of sikadur–30 is the most suitable adhesive material used with cfrp bar in nsm technique. the adhesive type consists of two compounds, compound a and compound b. the mix ratio was 3:1 as a:b. its main properties as supplied by the manufacturer are shown in table (11). 3-3 mix proportions the scc mix proportions are designed according to the european guidelines for self compacting concrete 2005 (efnarc, 2005) (17) .mix design of scc must satisfy the criteria on filling ability, passability and segregation resistance in addition to compressive strength which is equal 30 mpa. therefore, trial mixes are prepared by accurate weighing and the proportions of materials are modified to obtain a satisfactory self-compactability by evaluating fresh concrete tests. the details of the selected mix is given in table (12). 3-4 mixing procedures and tests of fresh concrete in this study emborg’s mixing procedure (emborg, 2000) (18) is adopted in order to achieve the required workability and homogeneity of scc mixes. several test methods are implemented in this study in order to ensure that scc mixes meet these requirements. the requisite test methods reported by (schutter, 2005) (19) and (kumar, 2006) (20) are slump flow and t50 cm tests; l-box test and v-funnel test as shown in figure (4), the fresh properties result of the mix are shown in table (13). this table indicates that the results are within the limits. 3-5 testing of hardened concrete 3-5-1 compressive strength test: the compressive strength of concrete ( cf  ) was tested on 300×150 mm concrete cylinders according to (astm c39/c39m-05) (21) while, the compressive strength of concrete ( fu ) was tested on (150) mm concrete cylinders according to (bs 1881-part 116:2000) (22) 3-5-2 splitting tensile strength test: the splitting tensile strength ( spf ) is determined according to the procedure outlined in (astm c496/c 496m-04) (23) . 3-5-3 flexural strength test: concrete prisms of dimensions (100×100×400) mm are cast according to (astm c 78-02) (24) procedure and tested to finding flexural tensile strength ( rf ). 3-6 casting and curing of the slab-column models according to (astm c 192/c 192m-05) (25) , all moulds were poured with scc and cured as shown in figure (5) 3-7 testing setup and instrumentation the punching test of slab-column models are performed by subjecting to a central punch load over the central column 120×120 mm by applying to the top face of slabs by a hydraulic jack of the universal testing machine of 2000 kn under monotonic loads up to ultimate load, see figure (6). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 04 the corners of slabs are supported by means of eight steel members, two for each corner as a steel levers to prevent lifting of the corners during the loading to satisfy closely the boundary conditions. the slabs were instrumented with three vertical dial gauges of 50 mm and accuracy of (0.01) mm at mid-span, at mid one quarter and at mid one side to monitor the deflection as shown in figure (7). the strain of concrete are measured by an ele extensometer with accuracy of 0.002 mm. many pairs of demec discs are used to monitor the strain concrete at selected levels of loading at several points on the tension face of slab; arrangement and distribution of these demec discs are shown in figure (7). the load was applied to the slab at a rate of 250 n/sec by means of the hydraulic jacks. at each load interval (5 kn), the cracks width was measured by crack meter (elecometer 900) with an accuracy of 0.02 mm; and crack propagation were marked. all instruments used in testing are shown in figure (8) 4experimental results and discussion 4-1 mechanical properties of each slab-column models the mechanical properties for each slab-column model are listed in table (14) from experimental work except the modulus of elasticity which is calculated according (aci318-11) (26) from equation (1). cc fe  4700 (1) it appears in table (14) that, the proportion between cube and cylinder compressive strength ( 'ccu ff ) for scc is about 1.215. from experimental result of hardened test of scc, the compressive cylinder and cube strength are ranged between (31.4-32-2) and (37.9-39.1), respectively. also, the splitting tensile strength and flexural strength are ranged between (2.37-2.44) and (3.49-3.54), respectively. 4-2 cracking behavior the first crack appears around the sides of the column on the tension face of the slab without cfrp bars about (28%) in control slab (cs) of the ultimate failure load . on the other hand, the first crack of all tested slabs strengthening internally with cfrp bars appears in the tension face of the slab about (24.1-26.7%) of the ultimate failure load. while, the first crack of model which strengthened by cfrp bars nsm technique appears at 20.7% of the ultimate failure load in the tension face of the slab around the sides of the column a crossing through the nsm bars. table (15), listed the first loads at tension and compression face of slab-column models, an increase in comparison with cs model and the percentage of the ultimate failure load. as the load is increased after the formation of the first crack, more cracks begin to appear and move towards the edge of the slab. in the compression face of the tested slabs, there are cracks that appear away from the edge of the column. except the slab (cs), cracks are found round the edge of the column only. the test results show that using cfrp bars in control slab (cs) increases the first cracking load in tension face between (14.3-90.5%) over the control slab without cfrp bars due to the increase in flexural capacity. the mechanism of development of cracks is almost the same for all models. the cracking pattern at failure for tension and compression face of each model is shown in figure (9). in slab-column models the use of cfrp bars reinforced, increased the size of the shear failure surface compared with control model cs. the maximum crack width was monitored throughout the test to recording the width of crack with increasing load (at each 5 kn) starting from first crack until near failure of the slab-column models. the width of first crack of slab-column models in tension face ranged between (0.03-0.08) mm. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 08 while, the width of crack in compression face increase quickly after appearing and ranged between (0.07-0.11) mm as shown in table (15). in general, slabs with cfrp bars have maximum crack width smaller than the control slab (cs) during the same stage of loading as shown in figure (10). at failure, the maximum crack width are (2.8, 2.26, 2.6, 2.21, 2.5, 2.48 and 2.16) mm for (cs, sruf1-nsm, srut, sruf1, srof, srdf and sruf2), respectively. the results show that, the maximum crack width decreases about (29.6%) in sruf2 model in comparison with cs model due to concentrated cfrp bars reinforcement in the immediate column region with flexural steel reinforcement, its restraining effect will increase and that reflects the decrease in the crack width. 4-3 load-deflection curves the recorded ultimate loads, deflections and failure mode for all slab-column models are presented in table (16). as the load on a test model was increased, the load-deflection behavior was noticed to have three distinguished stages: the elastic stage is an initial straight portion of the load-deflection curve, elastic-plastic stage is a nonlinear portion with distinct change in slope with increasing deflections and plastic stage is also a nonlinear portion but has characteristics in which a slight increase in load results in a larger deflection. the structural behavior of tested slab-column models are referred to here by their experimental load versus deflection as shown in figure (11) the initial change of slope of the load-deflection curves for all series started between (10.5-20) kn. this change in slope indicated the first cracking load. beyond that, all models behave in a rather certain manner. generally, the use of cfrp bars reinforcement internally to improve punching shear capacity of slab-column region is successfully due to enhanced strength above the punching shear capacity and increased stiffness as shown in figure (11) and as a result in table (16) that showed the increased ranged between (25.3-100%) for different distribution of same amount of cfrp bars. for the slab-column model cs, which is slab without cfrp bars, the experimental ultimate load capacity for this slab is 37.5 kn. an increasing in the ultimate load of sruf2 is 100%. whereas, the ultimate load of sruf1 and sruf1-nsm is higher than that of the reinforced concrete slabcolumn model cs by 81.3% and 80%, respectively. it is evident from this result and according to figure (11) that distribution of flexural cfrp bars reinforcement the slab-column models (sruf2, sruf1 and sruf1-nsm) had higher punching shear capacities, higher loads at first cracking in tension and compression face as mentioned previously, and higher postcracking stiffnesses. also, it was noted that the sruf1-nsm model which is strengthening by using nsm technique in two directions gave approximately the same efficiency to internal cfrp bars used in sruf1model. in slab-column model srof, the contribution of the compressive reinforcement of cfrp bars to the punching shear capacity was 33.3% which is small comparison with other distribution manner of cfrp bars but reduce the central deflection at failure. srdf model gave improving in punching shear capacity more than srof by only 8% due to the small region that distributed the cfrp bars through it. replacing the cfrp bars with steel bars in srut model reduced the punching strength with about 44.7% because cfrp bars have high tensile strength is 2704 mpa compared with steel reinforcement. also, srut model gave lower central deflection at failure by 15.7% due to lower modulus of the cfrp bars 163000 mpa compared with 200000 mpa for steel reinforcement. the deflected shape for slab-column models at failure is different along sides lateral from diagonal of slabs as shown in figure (12). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 00 4-4 concrete strain the strains in the concrete at tension face of the tested slab-column models were measured by using a demic gauge along half one principal and diagonal axes of symmetry. figure (7) shows the positions of demic points. from the figure (13), it can be seen that the concrete strain is small at the elastic stage as loading is applied, then it increases after the first crack when loading is continued. in the distribution of strains, the increase of strains started from the center of the slab toward the punching shear cracks, in principal and diagonal axes of tension surface of slab. at failure, the maximum concrete strain is observed around the sides of the column on the tension face of the slab especially toward the diagonal of slabs which is the strains was more than that in the principal directions as shown in figure (14), figure (15) and figure (16). the presence of cfrp bars at the bottom tension zone surface of slab-column region increasing the tension strength and some tensile stresses were carried by cfrp bars, and this was reflected to reduce the strains in the bottom tension surface. 5-conclusion based on the observed behavior and test results, the following conclusions are reached regarding the reinforced concrete slab-column models which improved punching shear resistance by using cfrp bars: 1the majority beneficial of using scc in casting slab-column model to ensure that adequate strength and durability are achieved due to capable of flowing through narrow column and extremely congested reinforcement, and provides a void-free surface. insufficient compaction will lead to the inclusion of voids, which not only leads to a reduction in compressive strength but strongly influence the natural physical and chemical protection of embedded steel reinforcement afford by concrete. 2the internally strengthened reinforced concrete slab-column model with cfrp bars show a significant increase in ultimate loads and the capacity of the slabs, this increase is about (33-100%) compared with the unstrengthened (control) slab. 3the effectiveness of the cfrp bars is depended substantially on distributed or arrangement manner in slab-column region. 4-the concentration of the flexural steel reinforcement in the column vicinity, also increased the punching shear capacity. 5even efficient to increase the punching shear load, the top reinforcement of cfrp bars will not change the brittle-type punching shear failure mode compared with bottom reinforcement. this means, the punching shear capacity of slab-column model was controlled by bottom flexural reinforcement rather than top reinforcement. 6nsm technique by cfrp bars in two direction of slab is very effective and nearly provided the same efficiency of internal reinforcement. 7the use of cfrp bars reinforcement in strengthening the slab-column region, results in a higher punching shear strength, a greater postcracking stiffness, a more uniform distribution of the strains in addition to reduce it, and smaller crack widths at full service loading compared with unstrengthening slab. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 04 6references [1] mccormac, j.c. and brown, r.h., 2014 " design of reinforced concrete", 9th edition, john wiley & sons, inc. 742pp. [2] varghese, p.c., 2009 "advanced reinforced concrete design", 2nd edition indian institute of technology madras, anna university. [3] zaghlal, m.y.a., 2009 "structural department punch resistance of slab column connection under lateral loads", m.sc., zagazig university. [4] aci committee 318, 2011 "building code requirements for reinforced concrete design", american concrete institute, detroit. mi. usa. [5] feretzakis, a., 2005 "flat slabs and punching shear: reinforcement systems" m.sc. thesis, univsity of dundee, dundee, uk. [6] al-shammary, d. sh. a., "some properties of porcelanite lightweight aggregate selfcompacting concrete," msc, thesis, university of technology, baghdad, iraq, 2006, 94 pp. [7] al-mishhadani, s.a. and al-rubaie, m.f., "a data base for self-compacting concrete in iraq", department of building [6] al-mishhadani, s.a. and al-rubaie, m.f., "a data base for self-compacting concrete in iraq", department of building and construction engineering, university of technology, iraq, eng. & tech. journal vol.27 no.6, 2009. www.pdffactory.com. [8] druta, c., "tensile strength and bonding characteristics of self-compacting concrete", msc. thesis, louisiana state university and agricultural and mechanical college, august, 2003. [9] okamura, h. and ouchi, m., "self-compacting concrete", journal of advanced concrete technology, japan, vol.1, no.1, pp.5-15, april, 2003. [10] aci committee 440, 2008 "guide for the design and construction of externally bonded frp systems for strengthening concrete structures (aci 440.2r-08)", aci manual of concrete practice, american concrete institute, farming hills, u.s.a. [11] iraqi specification, no.5, "portland cement", baghdad, 1984. [12] iraqi specification, no.45, 1984 "aggregate from natural sources for concrete and construction", baghdad. [13] astm standard, astm c 1240-05, 2005 "standard specification for silica fume used in cementitious mixtures", pp. 1-7 [14] astm c 494/c 494m-05, 2005 "standard specification for chemical admixtures for concrete", annual book of astm standards, american society for testing and materials, vol.04.02. http://www.pdffactory.com/ al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 04 [15] astm a 615/a615m-05a, 2005 "standard specification for deformed and plain billet-steel bars for concrete reinforcement", astm committee a01 on steel, stainless steel, and related alloys, west conshohocken, pa 19428-2959, united states, 5 pp. [16] hughes brothers, 2012 "carbon fiber reinforced polymer (cfrp) rebar aslan 200", manufacturer report. [17] efnarc: the european federation of specialist construction and concrete system "the european guidelines for self-compacting concrete; specification, production and use", pp.163, may, 2005. www.efnarc.org. [18] emborg, m., "self-compacting concrete: mixing and transport", brite euram, final report of task 8.1, pp.1-65, june, 2000. [19] schutter, g.d., "guidelines for testing fresh self-compacting concrete", european research project published by: systematic pan-european inter-laboratory, pp.1-23, september, 2005. available on websites: www.efca.info or www.efnarc.org [20] kumar, p., "self-compacting concrete: methods of testing and design", ie (i) journal-cv, vol.86, pp.145-150, february, 2006. [21] astm c 39/c 39m-05, 2005 "standard test method for compressive strength of cylindrical concrete specimens," annual book of astm standards, vol. 04.02 concrete and aggregates, west conshohocken, pa, united states, 7 pp. [22] bs 1881-part 116:1983, 2000 "method for determination of compressive strength of concrete cubes," british standards institute bsi, london, 11pp. [23] astm c 496/c 496m-04, 2004 "standard test method for splitting tensile strength of cylindrical concrete specimens," annual book of astm standards, vol. 04.02 concrete and aggregates, west conshohocken, pa, united states, 5 pp. [24] astm c 78-02, "standard test method for flexural strength of concrete (using simple beam with third-point loading)", annual book of astm standards, american society for testing and materials, 2002. [25] astm c 192/c 192m-05, 2005 "standard practice for making and curing concrete test specimens in the laboratory", annual book of astm standards, american society for testing and materials, pp.1-8. [26] aci committee 318, 2011 "building code requirements for reinforced concrete design", american concrete institute, detroit. mi. usa. http://www.efnarc.org/ http://www.efnarc.orgممكن al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 04 table (1): models identification symbols refer to cs control slab without cfrp bars as in figure1 sruf1 slab reinforced with cfrp bars with the same level of slab steel reinforcement, arrangement 1 srut slab reinforced with steel bars with the same level of slab steel reinforcement sruf1-nsm slab reinforced with cfrp bars by nsm technique srof slab reinforced with cfrp bars over the level of slab steel reinforcement srdf slab reinforced with doubly layer of cfrp bars, one layer over the level of slab steel reinforcement and the other with the same level. sruf2 slab reinforced with cfrp bars with the same level of slab steel reinforcement, arrangement 2 table (2): chemical analysis and physical properties of the cement chemical analysis compound composition chemical composition percentage by weight limits of ios no.5:1984 (7) lime oxide cao 61.23 silica dioxide sio2 20.898 alumina oxide al2o3 5.66 iron oxide fe2o3 3.38 magnesia oxide mgo 2.76  5.0% sulfate trioxide so3 2.34  2.5% if c3a <5%  2.8% if c3a >5% loss on ignition l.o.i 1.29  4.0% insoluble residue i.r 0.70  1.5% lime saturation factor l.s.f 0.77 0.66-1.02 main compounds (bogue’s equation) percentage by weight of cement tricalcium silicate (c3s) 40.31 dicalcium silicate (c2s) 31.11 tricalcium aluminate (c3a) 9.49 tetracalcium alumino ferrite (c4af) 10.43 physical properties physical properties test results limits of ios no.5:1984 (7) specific gravity 3.15 fineness: specific surface, blaine . (cm 2 /g) 3160  2300 setting time (initial) ( min.) 128  45 setting time(final) ( min.) 245  600 table (3): physical and chemical properties of fine aggregate properties test results limits of ios no.45:1984(8) specific gravity 2.62 sulfate content so3 0.37%  0.5% absorption 0.88% material finer than 75 µm (sieve no. 200) (%weight) 3.54%  5% fineness modulus 2.581 table (4): grading of fine aggregate sieve size (mm) passing % limits of ios no. 45:1984 for zone 2 (8) 10 100 100 4.75 93.8 90-100 2.36 83.1 75-100 1.18 75.1 55-90 0.60 58 35-59 0.30 29 8-30 0.15 2.9 0-10 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 03 table (5): grading of coarse aggregate sieve size(mm) passing % limits of ios no. 45/1984 (8) 14 100 100 10 100 85-100 5 18 0-25 2.36 0 0-5 table (6): physical and chemical properties of coarse aggregate properties test results limits of ios no.45/1984 specific gravity 2.6 sulfate content so3 0.08%  0.1% absorption 0.68% clay content 0.06%  2% table (7): physical and chemical properties of silica fume physical state fine powder. color grey odor characteristic. ph value at 20°c non melting point o c 160°c ignition point o c 365°c. density at 20°c 0.65 ± 0.1 kg/lit. thermal conductivity low bulk density 300 kg/m 3 table (8): typical properties of glenium 51 from the manufacture company catalogue main action concrete superplasticizer color light brown ph. value 6.6 form viscous liquid subsidiary effect hardening relative density 1.1 at 20c viscosity 128  30 cps at 20c transport not classified as dangerous labeling no hazard table required table (9): test results properties of steel bars φ (mm) area as (mm 2 ) perimeter (mm) weight (kg/m) pattern yield strength fy (mpa) ultimate strength fu (mpa) yield strain ultimate strain 6 28.3 18.86 0.230 c * 556 767 0.0027 0.049 (c* deformation pattern c consists of diagonal ribs inclined at an angle 60 degree with respect to the axis of the bar), al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 03 table (10): aslan 201 cfrp rebar physical properties item standards result test method barcol hardness ≥50 54.0 astm d2583 tensile strength, mpa (average-3.0 sigma per astm d7205) ≥2068 2704 astm d7205 modulus of elasticity, gpa (average value) ≥124 163 astm d7205 ultimate strain 0.017 0.017 astm d7205 table (11): technical properties of bonding materials properties sikadur 30 tensile strength (mpa) 26 31 mpa full cure, days 7(at +35 o c) compressive e-modulus gpa 9.6 gpa (according to astm d695) shear strength 18 mpa table (12): mix proportion cement kg/m 3 sand kg/m 3 gravel kg/m 3 sika fume% wt. of cement water kg/m 3 sp% wt. of cement w/c ratio w/p ratio c f  (28day) mpa 385 800 800 5% 194 0.8% 0.530 0.504 31.98 table (13): results of workability tests of the scc method result property limitations (13) slump flow (d) mm 780 filling ability 650 – 800 (t50 cm) sec. 3.4 2 – 5 v-funnel (tv) sec. 9.1 filling ability 6 – 12 time increase, (tv 5 min.) sec. 2.2 segregation resistance + 0-3 l-box (br) 0.88 passing ability 0.8 – 1.0 table (14): mechanical properties of slab-column models model symbol c f  mpa cu f mpa sp f mpa r f mpa c e gpa cs 32.0 39 2.42 3.53 26.6 sruf1 31.5 38.4 2.37 3.52 26.4 srut 31.4 37.9 2.41 3.49 26.3 sruf1-nsm 31.9 38.6 2.44 3.50 26.5 srof 31.7 38.1 2.40 3.54 26.5 srdf 31.5 38.4 2.38 3.51 26.4 sruf2 32.2 39.1 2.42 3.50 26.7 average 31.7 38.5 2.41 3.51 26.49 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 44 table (15): cracking and ultimate loads model symbol 1st crack in tension face increase in prt, % 1st crack in compression face increase in prc, % ultimate load pu (kn) prt/pu% prc/pu% load prt (kn) width mm load prc (kn) width mm cs 10.5 0.08 --------23 0.11 --------37.5 28.0 61.3 sruf1 17 0.04 61.9 50 0.09 117.4 68.0 25.0 73.5 srut 12 0.06 14.3 38 0.07 65.2 47.0 25.5 80.9 sruf1nsm 14 0.05 33.3 50 0.09 117.4 67.5 20.7 74.1 srof 12.5 0.06 19 45 0.07 95.7 50.0 25 90.0 srdf 13 0.04 23.8 40 0.07 73.9 54.0 24.1 74.1 sruf2 20 0.03 90.5 65 0.08 182.6 75.0 26.7 86.7 table (16): test result of slab-column models model symbol ultimate deflection (mm) ultimate load (kn) increase in ultimate load over cs,% failure mode central mid of side quarter cs 17.23 12.35 9.85 37.5 --------punching shear sruf1 21.23 16.85 13.82 68 81.3 punching shear srut 18.35 11.88 10.14 47 25.3 punching shear sruf1-nsm 22.1 15.01 10.35 67.5 80 punching shear srof 18.8 16.19 11.6 50 33.3 punching shear srdf 18.25 15.89 12.56 54 44 punching shear sruf2 22.23 16.85 13.73 75 100 punching shear figure (1): details reinforcement of the slab-column model (all dimentions are in mm) al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 44 figure (2): details of the slab-column models al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 44 figure (3): the mould and the sruf1-nsm model figure (4): tests of fresh self compacting concrete v-funnel l-box slump flow al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 48 tying of steel and moulds preparation casting process figure (6): apparatus of the testing of slab-column models curing process and paint figure (5): casting and curing conditions al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 40 figure (7): configuration of demec points for strain and dial gauge for deflection figure (8): instruments that used in testing figure (9): cracks pattern at failure for all models demec point dial gauge dial gauge ele extensometer and demec discs elecometer 900 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 44 figure (9): continued al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 44 figure (9): continued figure (10): maximum crack width-load curves for slab-column models al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 44 figure (11): load versus mid span deflection for all slab-column models figure (12): deflected shape at failure for all slab-column models figure (13): tensile strain versus distance along lateral sides of cs-model al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 43 figure (14): tensile strain versus distance along lateral sides of all models figure (15): tensile strain versus distance along diagonal axis of all models figure (16): tensile strain versus distance for sruf2 model al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 731 studying some of the mechanical properties of unsaturated polyester reinforced by re-cycled natural materials shaimaa hilal kamel assist. lecturer mechanical engineering department, university of technology s.h_eng@yahoo.com received 15 february 2015 accepted 6 may 2015 abstract reinforcement of unsaturated polyester by particulates plays is an important role in the improvement of the mechanical properties of high performance materials. hence, the mechanical behavior of recycled (grapes and dates) particulate polyester composites was studied in order to develop an engineering material for industrial applications. different percentages (0, 1.5, 3.5 and 5) % of the reinforcement particles were added to unsaturated polyester resin. numbers of mechanical tests were included (thermal conductivity test, hardness test, dielectric testing, tensile test, impact test). the results showed that the hardness and dielectric constant of filled unsaturated polyester increase with the increment of the percentage of grapes and dates particles, while impact resistance decreases. on the other hand the thermal conductivity increase at (1.5%) of percentages and decreases of (3.5%, 5%) of grapes particles while the value of thermal conductivity decrease by (1.5%) and increased when increasing (3.5 %, 5%) of the dates particle. the tensile strength improves of grapes reinforcing particles and increase with an increase in the particle percentage of grapes and the value of tensile strength increases with the dates particle content (1.5%). also that the percentage of (3.5 %) represents the greatest value for the modulus of elasticity for unsaturated polyester reinforced with dates particle and the percentage of (5 %) represents the greatest value for the modulus of elasticity for unsaturated polyester reinforced with grapes particle. keywords: mechanical properties, unsaturated polyester, grapes particle, dates particle, composite materials. دراسة بعض الخواص الميكانيكة للبولي أستر الغير مشبع المدعم بمخلفات المواد الطبيعية الخالصة على هذا االساس تلعب دوراً هاما في تحسين الخواص الميكانيكية الداء عالي للمواد. و المدعمة للبولي استر الغير المشبعالدقائق تم اضافة نسب من العنب والتمر من أجل تطوير المادة الهندسية لتطبيقها في الصناعةنوى السلوك الميكانيكي لدقائق تم دراسة لمشبع وقد اجريت مجموعة من االختبارات الميكانيكية عند دعمة لراتنج البولي استر الغير ام( ال%5,%3.5,%1.5,%0الدقائق ) العزل الكهربائي,اختبار الشد,اختبار الصدمة( اختبار الصالدة,اختبار التوصيل الحراري , اختبار درجة حرارة الغرفة شملت ) نب والتمر كما ان مقاومة وقد أظهرت نتائج البحث ان الصالدة وثابت العزل الكهربائي تزداد بزيادة النسب المضافة من الع ( وتقل القيمة %1.5حيث لوحظ ان قيمة التوصيل الحراري تزداد عند نسبة ) .الصدمة تقل بزيادة النسب المضافة من العنب والتمر mailto:s.h_eng@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 731 ( %5,%3.5( وتزداد عند زيادة النسب )%1.5( لدقائق العنب بينما قيم التوصيل الحراري تقل عند نسبة )%5,%3.5عند نسب ) تتحسن وتزداد مع زيادة النسب المضافة من دقائق للبولي استر الغير المشبع عمة دالم بالتمر. مقاومة الشد لدقائق العن لدقائق ( من دقائق التمر. كذلك قيمة معامل المرونة يكون اعظم قيمة له عند نسبة %1.5العنب .وقيم مقاومة الشد تزداد عند نسبة ) لي استر الغير المشبع واعظم قيمة لمعامل المرونة لدقائق العنب المدعمة للبولي استر الغير ( لدقائق التمر المدعمة للبو3.5%) (. %5المشبع عند نسبة ) مركبة.المواد الالميكانيكية, البولي أستر الغير مشبع, دقائق العنب, دقائق التمر, الخواص الكلمات المرشدة: 1introduction the use of polymer matrix composite has found a wide application in our modern day world. this is as a result of the combination of properties which these materials possess. some of the properties of polymer matrix composites include specific strength, high modulus, good fracture and fatigue properties as well as corrosion resistance [1]. from time immemorial, man has always strived to make use of available materials at his disposal to better the lots of the people around him and the society in general. these efforts had led to various research works being carried out for decades by trying to find alternatives and/or substitutes for some materials that appear to have outlived their existence. studies on composites have shown that new materials have been discovered such as metal matrix composites, ceramic matrix composites and polymeric composites which were all found to be capable replacements in the many industrial applications, when compared to old used materials. there have been little developments in the use of natural fiber or particulates as reinforcement materials for polymeric composite. though findings have shown that natural fillers reinforced polymeric materials provide materials engineers with a new group of materials that offer exceptional combinations of mechanical properties that make them equivalent to steel applications. there needs to make use of available materials/resources to produce composites with an unusual combination of properties that no traditional materials like ceramics, polymeric materials or alloys possess. it is the applications of these materials used in the industries that are the driving force behind the discovery of new materials which have led to the designing of materials for specific applications often called composites . generally, composite are produced when two or more materials are joined together to give a combination of properties that cannot be attained otherwise according to the principle of combined action, better property combinations are fashioned by the judicious combination of two or more distinct materials [2]. natural filler-reinforced polymers provide increases in the degradability capability of the resulting product [3]. fibers like oil palm empty fruit bunch, kola nitida wood fiber, as well as several fillers such as rice husk have been used as reinforcing agents of different thermoplastic and thermosetting plastic resins [4,5]. there is an overwhelming interest in filler and natural fiber reinforced polymers owing to their ease of processing and low cost as some of these fillers are regarded as waste. in the development of polyester/eggshell particulate composites, the density and hardness values of the polyester/eggshell particulate composites increased steadily with the increasing eggshell addition, compressive strength, flexural strength and impact energy increased [6]. the effect of untreated and treated coconut shell reinforced unsaturated polyester composites was studied and it was observed that the mechanical and thermal properties of unsaturated polyester/coconut shell composites were enhanced [7]. in recent years, many studies have been dedicated for utilizing cellulose fillers such as coconut shell, wood, pineapple leaf, palm kernel shell, etc. as fillers in order to replace the synthetic fillers through utilization of natural fillers or reinforcement in thermoplastic and thermoset polymer composites in an attempt to minimize the cost, increase productivity and enhance the mechanical properties of the product [8]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 731 investigated the cure characteristics and the physico-mechanical properties of natural rubber, standard nigerian rubber, snr10 filled with cherry seed shell (css) and standard carbon black cb (n330) was determined. the tensile strength of both css and cb-filled vulcanizates increased to a maximum at 40 phr filler content before declining. the module (m100 and m300 ,specific gravity (s.g), hardness and abrasion resistance increased while the elongation at break and dunlop resilience decreased with increasing the filler content for both vulcanizates [8]. the aim of this research is to studying some of the mechanical properties of unsaturated polyester reinforced by some local residual materials such as grapes and dates particles. 2experimental procedure 2.1. materials 2.1.1. matrix polymer unsaturated polyester produced by (sir) is used. unsaturated polyester is in the form of a transparent viscous liquid at room temperature and is one of the types of polymers solidified thermally (thermosets) it turn into solid state when adding hardener (methyl ethyl keton peroxide) mekp is on the transparent liquid is added by the form (2g) to (100g) of unsaturated polyester resin at room temp. (percentage of styrene 32, viscosity at 25 ºc is 1000 cups, appearance transparent, ph solid basis 22, specific gravity 1.15). upon completion of the addition hardener and catalyst to the resin mix, mixing process immediately begin mediated manual mixing for 8-10 minutes until the harmonious mixture and when exceeding this time period becomes a viscous mixture is very high as well as the temperature rises, leading to accelerating the hardening process and this hinders the casting process as well as for the final product to contain a high air bubbles. aster features unsaturated polyester resin, mechanical properties and good scalability good correlation with various other materials, electrical insulation and good thermal and surface quality after sclerosis. on sclerosis for the user of the resin must be not less than 3 hours at room temperature. in order to complete the cross-linking process and reduce the proportion of contractions the resin is ready for a final examination. 2.1.2. reinforcing particle two types of particles were used in this research. these types were grape and dates powder. the particles were collected and crashed by using an electrical mill. the particulates were received by vibratory sieve shaker to get a suitable size. the grain size in this research was (100 µm). the seed particle was used (0,1.5, 3.5 and 5) %. the samples were prepared by mixing unsaturated polyester with grape and dates powder using different particle contents. the two particle powder was supplementary to polyester and hardener and then they were homogeneously mixed at room temperature. the composite was cast into the mold according to the test and left 48hr to complete. 2-2mechanical tests 2-2-1 thermal conductivity test this test was carried out in accordance with lee`s disk which manufactured by (griffin and george company england) the thermal conductivity (k) calculated from the number of equation (2) and determine the quantity of heat that flows through the cross sectional area of the sample per unit time (e) from the number of equation (1) [14]. ( ) [ ( ) ] ( ) ( ) [ ( ) ] ( ) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 where i = current in (ampere). v=applied voltage in (volt). r=radius of disk in (mm). e= represents the quantity of heat that flows through the cross sectional area of the sample per unit time (w/m 2 . o c). ta, tb, tc= temperatures of the disks a, b, c ( o c). da, db, dc=thickness of the disc a, b, c (mm). ds=thickness of the sample (mm). k=thermal conductivity (watt/m. o c). 2-2-2 impact test samples were prepared for impact standard dimensions (4*10*80) mm and without notches according to the global positioning system (iso 179) using charpy impact device to test the impact. the device depends on the energy required to break account sample hammer device that strikes the sample at room temperature. the impact strength is calculated by applying the equation (3): gc = uc /a (3) where gc is the impact strength (j/m 2 ), uc is the fracture energy (joule), which is determined from charpy impact test instrument a: the cross section area (mm). 2-2-3 hardness test the concept of hardness can be considered by measuring the plastic deformation the material suffered under the influence of external stress. using shore device (d) (shore d no.dw53505) hardness test and private measuring the hardness of polymeric materials was conducted in a manner stitches tool penetration and bitmap tool stitches inside surface article under a certain load, where the resistance moves straight to the counter measurement to determine the value of hardness to read directly from the screen of the device. this method successfully, the sample surface must be very flat and diameter is greater than (30 mm) and a thickness of more than (3 mm). 2-2-4 tensile test this test was used determine the properties of composite materials under the influence of axial load (pulling in one direction) by (tensile test h50kt (tinius olsen)) testing machine, england (uk). in all tests, the rate of loading this property (50kn) operating at a crosshead speed of 10 mm/min was used for the tensile testing of the samples. the tensile test was performed on flat specimens. the tensile test specimen preparation and testing procedures were conducted in accordance with the american society of testing and materials (astm d412). 2-2-5 modulus of elasticity elastic modulus test from stressstrain curves (tensile test). load – elongation curves were obtained for eight the samples and the slope of these curves, the modulus of elasticity can be calculated. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 747 2-2-6 dielectric test according to astmd150 the instrument used was leybold – heraeus (germany) which represents an electrical circuit (in series connection) consisting of a capacitor, resistor, ammeter, coil, and frequency generator. the sample with dimensions (40) mm diameter and 5mm thickness is placed between the capacitor plates followed by alternating the frequency of the power supply till reaches the maximum current value which represents the resonance frequency value (fr). after that, the (fr) was determined by the existence of air only, i.e, without the presence of the sample. dielectric constant (εr) was calculated from equation (4): ( ) where ε and εo are the permittivity of the medium and the free space permittivity (8.8 x 10-¹² f m -1 ), respectively. 3result and discussion 3-1 thermal conductivity figure (1) shows the relationship between the value of thermal conductivity with percentages on addition particles (grapes and dates). it was noticed that the thermal conductivity increase at 1.5% and then it decreases at other percentages of (3.5%, 5%) for grapes particle. on other hand, the thermal conductivity decreases when the percentage of the dates particle is 1.5% while it increase for the percentage (3.5 %, 5%). because of the thermal conductivity of composite is made of two phases one for the reinforcement material while the other for matrix (unsaturated polyester) for each phase different thermal conductivity from the other. reinforcement material has a crystalline structure in which the atoms organize according to a three-dimensional network. thermal conductivity of reinforce phase is less than thermal conductivity of polymer materials due to random arrangement and this reduces the probability of dispersion of photons or configure complex constructs leading to emergence gaps that work. the results have good agreement with result obtained by [9]. 3-2 impact testing figure (2) illustrates the effect of the grapes and dates particles percentage to resist impact composite materials with a basis of unsaturated polyester reinforced of particle where notes that the value of impact resistance decreases with increasing of the particles percentage grapes and dates because of the particles of the ability of resistance to impact recipe fragility compared with materials basically as well as the impact resistance to particles of grapes and dates of less impact resistance of unsaturated polyester as there results good agreement with result obtained by [10,11,12] 3-3 hardness testing figure (3) shows the effect of the particles percentage added in hardness. test it shows that the hardness of unsaturated polyester increasingly adding grapes and dates of particles and continue hardness increase with the increase in the percentage, and the concept of hardness can be counted a measure of the plastic deformation of the material can suffer when under the influence external stress and so the addition of particles raise the hardness of material due to increased resistance to deform plastically. where composite materials possessed the highest value at the percentage (3.5%) a (86.25 shore) of particular dates as their results good agreement with results obtained by [10,13]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 3-4 tensile strength from figure (4), it can be seen that the grapes reinforcing particles improves the tensile strength and it increase with the increment in the particles percentage of grapes and the value of tensile strength increases with the dates particle content 1.5%, due to the power of high linkage between the matrix material and reinforcement material, which leads to reducing the slip during the tension and decrease with the increase of dates particle percentage due to the bonding force between the matrix (unsaturated polyester) and polymer molecules prohibited the movement of the polymer chain and reduced chain slippage. on the other hand because of the probability for the formation of a filler network is enhanced with further increase in loading which is caused by a closer distance between aggregates in the polymer system and a better filler-filler interaction as their results good agreement with results obtained by [14,15]. 3-5 modulus of elasticity figure (5) shows the relationship between the modulus of elasticity and the percentages of the grapes and dates particles which were added to unsaturated polyester.the amount of these particles plays an important role by impeding increasing by the slipping of polyester resin chains [14]. knowing that, the chains require high stress to bend them in the narrow space between the particles. so, the percentage of (3.5 %) represents the greatest value for the modulus of elasticity for unsaturated polyester reinforced with dates particle and the percentage of (5 %) represents the greatest value for the modulus of elasticity for unsaturated polyester reinforced with grapes particle .this may be due to the strengthening mechanism and the nature of bonding adhesion of particles mentioned and causes the fraction between the particles and the matrix causes slipping among the particles in tension as there results good agreement with result obtained by [14,15]. 3-6 dielectric testing the effect of particle adding on unsaturated polyester is shown in fig (6), when an increase percentage of particles, increasing dielectric constant because the interaction between surface particles and unsaturated polyester is poor, the polarizability is also effected on dielectric constant, if polarizability is higher the dielectric constant will be high as there results good agreement with result obtained by [16]. 4conclusion: from the results and discussion above, the following conclusions where observed 1the hardness and dielectric constant of the unsaturated polyester increase with increase of addition percentage of particles (grapes and dates). 2the impact resistance of unsaturated polyester reinforced with particles decreases with increasing of the percentage grapes and dates. 3the value of thermal conductivity increase at (1.5%) and decreases than the value at percentages of (3.5%, 5%) of grapes particle while the value of thermal conductivity decrease by (1.5%) and increased when increases at percentages (3.5 %, 5%) of the dates particle. 4the tensile strength improve of grapes reinforcing particle and it increase with an increase in the particle percentage of grapes and the value of tensile strength increases with the dates particle content (1.5%) and that the percentage of (3.5 %) represents the greatest value for the modulus of elasticity for unsaturated polyester reinforced with dates particle and the percentage of (5 %) represents the greatest value for the modulus of elasticity for unsaturated polyester reinforced with grapes particle. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 743 5references [1] agunsoye, j. o. ; aigbodion, v. s. ; talabi, s. i. and olumuyiwa, a., "effects of silica ceramic particle sizes on the properties of recycled polyethylene composites", advances in natural science, vol. 6, no. 3, pp. 14-22,2013. 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[8] osabohien, e and egboh, s. h. o., "cure characteristics and physico-mechanical properties of natural rubber filled with the seed shells of cherry (chrysophyllum albidum)" j. appl. sci. environ. manage. , vol. 11 (2),pp: 43 48, june, 2007. محمد ضياء وم.فيزياوي سعد غازي أحمد وم.فيزياوي وليد خالد عبد الظاهر "دراسة خاصية التوصيل الحراري أ.د.بلقيس[9] . journal of college of education ,1177في ظروف مختلفة لمواد متراكبة دقائقية" هناء عرير سميج "تأثير التقوية بمسحوق اوكسيد الزنك على الخواص الميكانيكية لمادة متراكبة ذات اساس من البولي أستر [10] .1177, 71, العدد 11غير مشبع", مجلة الهندسة والتكنولوجيا ,المجلد كية لمواد متراكبة ذات أساس ،د.كاظم مطر شبيب و قحطان عدنان حمد "دراسة الخواص الميكاني د.سهامة عيسى صالح[11] .1171, 4, العدد 11بوليمري مقواة بااللياف والدقائق", مجلة الهندسة والتكنولوجيا ,المجلد [12] nasif ,r.a., "study the effect of volume fraction of mica with different particle size on the mechanical and electrical properties for unsaturated polyester composites", eng. &tech. journal, vol.30, no.20, 2012. أنعام وادي وطن , "دراسة بعض الخواص الميكانيكية والحرارية للبولي أستر غير المشبع والمدعم بدقائق سيراميكية" , [13] diala, jour., volume, 37 ,1111. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 744 [14] oleiwi, j.k.; othman, f.m. and ghaze, i.f., "a study of mechanical properties of poly methacrylate polymer reinforced by silica particles (sio2)", eng. &tech. journal, vol.31, part (a), no.15, 2013. [15] nassir, n.a.h., " studying the effect of nano carbon black on mechanical properties of uusaturated polyester resin", the iraqi journal for mechanical and material engineering, vol.13, no4, 2013. [16] hazz, s. q. and ahmed, a.m.,"dielectric properties of carbon nanotubes-unsaturated polyester nanocomposites", journal of the faculty of education (3), 2013. figure (1): the relationship between the thermal conductivity of unsaturated polyester reinforced with grapes and dates particles figure (2): the relationship between the impact strength of unsaturated polyester reinforced with grapes and dates particles 0 0.5 1 1.5 2 2.5 3 0 1 2 3 4 5 6 t h e r m a l c o n d u c t iv it y ( k * 1 0 0 0 ) (w /m .c ) particles percentages (%) gr da 0 0.001 0.002 0.003 0.004 0.005 0.006 0 1 2 3 4 5 6 im p a c t s t r e n g t h ( j/ m m ^ 2 ) particles percentages (%) da gr al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 figure (3): the relationship between the shore hardness of unsaturated polyester reinforced with grapes and dates particles figure (4): the relationship between the tensile strength of unsaturated polyester reinforced with grapes and dates particles 77 78 79 80 81 82 83 84 85 86 87 0 1 2 3 4 5 6 s h o r e h a r d n e s s particles percentages (%) da gr 0 10 20 30 40 50 60 0 1 2 3 4 5 6 t e n s il e s t r e n g t h ( m p a ) particles percentages (%) da gr al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 figure (5): the relationship between modulus of elasticity of unsaturated polyester reinforced with grapes and dates particles figure (6): the relationship between dielectric constant of unsaturated polyester reinforced with grapes and dates particles 0 500 1000 1500 2000 2500 3000 0 1 2 3 4 5 6 m o d u lu s o f e la c t ic it y ( m p a ) particles percentages (%) da gr 1.000 1.005 1.010 1.015 1.020 1.025 1.030 1.035 1.040 0 1 2 3 4 5 6 d ie le c t r ic c o n s t a n t particles percentages (%) da gr 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 51 وامكانية معالجتهااالسفلتي التبليط عيوب جاسم عطية علوان بابل –مدرس / المعهد التقني 1122تشرين الثاني 01ُقبل في 1122تشرين االول 12ًأستلم :الخالصة مدينة الحلة من التبليط ألحد الطرق الرئيسية في وحالة يهدف البحث ألجراء دراسة ميدانية ومختبرية لمعرفة عيوب االمريكية القياسية وبدون اي pci) خالل تحديد عيوب التبليط واسباب ظهورها بطريقة معامل حالة التبليط) فحوصات مختبرية للتبليط ومقارنة تحديد حالة التبليط بالطريقة التقليدية السائدة بعد اجراء مختلف الفحوصات وما التقنيات باستخدام الى كيفية معالجة هذه العيوب السطحية ايضا ق البحث يتطلبه ذلك من كثرة الجهد والكلفة، وتطر ( قطاع 50الحديثة اثناء تصميم التبليط او عند معالجة هذه العيوب لتقليل او منع ظهورها. تطلب العمل دراسة) وتدوين مختلف عيوب (م واجراء الكشف الموقعي07.( كم وعرضه )5.0) لهألحد اتجاهي الطريق االسفلتي وطو يجاد قيمة)pciالتبليط بطريقة معامل حالة التبليط ) ( لكل قطاع لتحديد حالة مقاطع التبليط . تم pci( وا ( عينات اخرى من تبليط نفس 01( و)core test( عينات اسفلتية بجهاز فحص اللباب االسطواني)01اختيار) ( قطاع من تبليط الطريق كانت 01( ان)pciطريقة ال) نتائج المواقع ألجراء مختلف الفحوصات المختبرية. أظهرت ( عيب قياسي بهذه الطريقة والتي 19( عيوب من )8(في التبليط كانت ضعيفة وان ( قطاع2(0بحالة متوسطة وان يذ دعمتها نتائج الفحوصات المختبرية في الطريقة التقليدية لتحديد حالة التبليط وان اسباب ظهور عيوبه هي سوء تنف طبقات تبليط الطريق وعدم كفاءة الطبقة االسفلتية السطحية لمقاومة أحمال المرور وإلصالح العيوب نحتاج الى ازالة رذاذي ، اضافة طبقة من االسفلت الرملي والى اضافة الحصى الناعم اليها احيانا والىرش طبقة اسفلت مواقع.في بعض ال الطبقة السطحية واعادة اكسائها معالجة العيوب، تسليح االسفلت ، التبليط حالة معامل طريقة، التبليط االسفلتيعيوب :رئيسيةكلمات 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 51 asphaltic pavement distresses and the possibility of repair jassim atiya alwan babylon technical institute / lecturer abstract the aim of this research is to prepare a site & laboratory studying to define the distresses and the pavement condition for one of the main roads in hilla city by defining pavement distresses and their arising causes by standard american pavement condition index (pci) method without any pavement laboratory tests and compare pavement condition definition with the familiar classical method after executing different tests which is required much efforts & cost, also the research is including how to repair the arising distresses with the recent technics which have to be employed during road pavement design or at distresses repairing to decrease or to prevent their arising. (50) road sectors were required for one of the asphaltic road directions with(5.0)km length,(7.0)m width and listing their different pavement distresses by site inspection using (pci) method to find the pavement condition index (pci) values for each sector to define the pavement sectors condition. a selection of (10) asphaltic samples by core test and another(10) samples of road pavement from same locations to execute different tests. the (pci) method values results showed that (30) sectors are in fair conditions, (20) sections are poor and the pavement include (8) distresses from a (19) standard distresses in this method which is supported by test results of classical method for pavement condition definition and its distresses arising due to bad site execution of road pavement layers, inefficient wearing course to resist traffic loads and these distresses should be repaired by spraying emulsion fog seal, adding sandy seal layer with fine gravel some times and removing with repaving wearing course in some locations. :المقدمةاوال": تعتبر عيوب التبليط من المشاكل الرئيسية التي تؤثر بشكل فعال على استخدام الطرق وكفائتها وتقليل عمرها المواصفات . لقد صنفتهااصالحو الخدمي مما يتطلب االسراع في تحديد هذه العيوب ومعرفة اسباب ظهورها (عيب قياسي 01هذه العيوب الى) (pci)طريقة معامل حالة التبليط باستخدام [astm d5623,2006] االمريكية تشوه ، تآكل الركام وعيوبوالتجويه السطح تفككك (surface defectsسطحية) عيوببأنها واعتبرت بعضها كالشقوق التمساحية cracking)تشقق) وعيوبجات مو كالتخدد)االخاديد(، الت surface deformation)) سطحال 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 51 ((alligator ترقيع ) وعيوب، الحافات ة، البلوكي (patching ما كمع ارقامها ةمبينهذه العيوب بسبب التصليحات و بأنه [shixiu & lingyun,2012]ذكر الباحثان (ادناه.0ورد في هذه المواصفات في الجدول رقم) لحالة المالئمة هي(k=0.000064rd3فأن القيمة) pci)للحصول على قيمة الخصم لعيب التخدد بطريقة ال) الى تؤدي التي الرئيسية االسباب ان] khanna,2992[ذكر(تمثل عمق التخدد بال)ملم(. rdالفعلية حيث ان) التبليط احمال مرورية عالية اكثر من قابليته التصميمية، سوء تنفيذ طبقات الى التبليط تعرض هو العيوب هذه ظهور ارتفاع درجات و مطار التبليط اتصريف مياه تأثيرالطريق وعدم القيام بالسيطرة النوعية الكافية لمواد التبليط ، تقويةاجراء التصليحات الخاصة وذلك ب دوري او ،صيانة التبليط بشكل يومي يجب مراقبة و لذاالحرارة احيانا عند ظهورها في التبليط تحديد عيوب ه يجبان turkey et al,2005] و khanna،2992[. وذكرالطريق بطبقة اضافية تصنيفها وتحديد درجة شدتها ومن ثم تحديد الطريقة المناسبة لمعالجتها ، وقد مرت عملية تحديد هذه و التبليط (0.33استخدم لتحديد استوائية سطح التبليط طريقة االنحراف بجسر بنكلمان وطوله ) حيثالعيوب بأساليب مختلفة ذلك و الخاصة هامواصفاتبقيمها بالقيم الموجودة م او آلة قياس االستوائية والذي تجرهما سيارة ألخذ قراءات تقارن طريقة مستوى الخدمة )االداء( الحالي والذي تعتمد على اجهزة قياس لتحديد استخدمت لتحديد حالة تبليط الطريق، ( وهي طريقة pci(، طريقة معامل حالة التبليط )aashtoمواصفات ال) حسبعيوب التبليط وخشونة سطحه u.s army corps of)اي جمعية المهندسين االمريكية من قبل ها ادها واعتميطور تم تالذي و بيفر engineersاستخدمت بوالية تكساس في البداية ثم اعتمدت بنطاق واسع واعتبرت مؤخرا" الطريقة الدقيقة ( وقد falling weight deflectoوالموضوعية لتقييم حالة تبليط الطرق وكذلك طريقة جهاز الحمل الساقط ) meter) تحديد حاجتها لإلصالح و يستخدم لتقييم القدرة االنشائية لتبليط الطرق و التبليط االضافي.لطبقات الطريق وسمك ((modulus of elasticityمعامل المرونة بايجادبتحديد مواقع الخلل لتقوية ظهرت في بداية السبعينيات من القرن الماضي مجموعة ابحاث بأنه [al -qadi and appea,2003]ذكر وقد بدءت في الواليات المتحدة االمريكية ثم انتشرت في الدول االخرى وتركزت على تقوية الطبقات طبقات التبليط ارضية بإضافة طبقة تسليح بمواد صناعية العليا من الطريق والتي تتعرض ألحمال المركبات العمودية (geosynthetic )وان وضع طبقة منها ما بين طبقة ما تحت التدرج وهي نسيجية او معدنية(subgrade) fanin et] ستكون فعالة في تحسين اداء التبليط واطالة عمره. وذكر الباحثون subbase)) وطبقة ما تحت االساس al.,1996,hufenus et al.,2005] تربةوانها تقوي الموقعية لظروفا بمقاومة تجريبياثبتت نجاحها بأن هذه المواد ا ر الباحثون لقد ذك الضعيفة بدال من تثبيتها كيميائيا او استبدالها بأخرى . التدرج ما تحت et al.,2010, palmeira et al.,2010] [qian م ستخدام طبقة واحدة منابأن(شبك الgeogrid) البالستيكي بين اي تقليل عمق االخاديد وزادت من زاوية توزيع الجهد ادى الى التدرج وطبقة ما تحت االساسطبقة تربة ما تحت 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 51 الغير مسلح ما تحت التدرج وماتحت االساس مقارنة بالمقطعطبقة قللت من الجهد العمودي على السطح ما بين لى تسليح الطبقة اما بالنسبة ا.عادة تأهيلهواالتبليط او من نظام صيانته اصبحت هذه المعالجة جزءا من تصميمو تسليح طبقة االسفلت السطحية او الرابطة عند االنشاء او طبقة التبليط بأن [baek et al. ,2003]فقد ذكراالسفلتية ادى الى تقليل اجهاد steel netting))الفوالذي شبك طبقة من المعند الصيانة باستخدام (overlay)االضافية .الطبقة المسلحة واخر بدء التشققاتالحرارة واالحمال بأسفل ان من االمريكية ( بوالية فرجينياvirginia smartتم في طريق) عما [elseifi and al-qadi,2003]اشار الباحثان وطبقة التبليط االضافية او في داخل طبقة بين طبقة التبليط السطحية المتضررةالفوالذي اضافة تسليح الشبك د انشائها قد نجح بوضوح في اعاقة حدوث الشقوق في التبليط حيث انه سيعمل كتسليح، مانع التبليط السطحية عن يمثل الدور الرئيسي لمنع حدوث stress)للجهد،عازل، مرشح ومانع للرطوبة وان قيامه كمانع لحدوث الجهد) االخاديد وتشققات جهد شقوق التبليط ألنه سيعوض التبليط عن نقصه في مقاومة جهد الشد ويجعله مقاوما لحدوت حيث (%11 –01(سم قد زاد عمرها الخدمي من)01(، وان تسليح طبقة التبليط االضافية بسمك )fatigueاالعياء) %(21والناتج من احمال المركبات وب) %(00(العرضي في اسفل الطبقة ب)strainان التسليح قلل من االجهاد) ان تشققات االعياء[lee,2008] ذكر الباحث ْم. (00( ْم الى)22حرارة من)اليومية لتغير الالحرارية من اجهاد الدورة ((fatigue مواصفة بوضوح السطحية وقد عرفته هي من اكثر العيوب الموجودة في طبقة التبليط االسفلتيايضا بأنه عيب التبليط الذي يظهر بسبب الحمل المتكرر والذي تقل عنده -aashto t321)2113/10ال) الحظ الباحثون تأخر هذا التشقق في التبليط و ،صالبتها االولية من%( 01)الى طبقة االسفلت stiffness)صالبة) احد وهو ] [vacri,2007اشارت نتائج بحثالمسلح عندما يصل فيزيائيا الى شبك التسليح المدفونة في التبليط. في جامعة فالنتائج الرئيسية التي توصلت اليها ابحاث الجامعات العالمية حول ذلك ابحاث تسليح االسفلت الى اطال التسليح من عمر كاليري فقدجامعة في (،0االعياء لألسفلت المسلح بعامل يصل الى) نوتنكهام تحسن عمر قلت ف في جامعة بالرمواما %(30قل ظهور الشقوق بنسبة)في جامعة بارما (،02-0التبليط بعامل يتراوح بين) %(.01اجهادات االخاديد بنسبة) :الهدف من اجراء البحثثانيا": ومقارنتها بالطريقة التقليدية هتحال تحديد ثم ( الحديثة لتحديد عيوب التبليط االسفلتيpci)ال طريقة آليةمعرفة ألجل العيوب عند وكيفية معالجة هذهوحالة التبليط تحديد خللذو الكلفة والجهد ل المختبرية الفحوصاتوالتي تعتمد على المختلفة. تصميم طبقات الطريق باستخدام مواد التسليحلمنع ظهورها عند ظهورها والتخطيط 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 51 :":المواد المستخدمة بالبحثثالثا وهي شريط القياس العيوبادوات قياس الى (pci)مواصفات ال فقد اشارتعيوب التبليط ألجل تحديد -0 العيوب ومسطرة معدنية لقياس مقدار العمق لتحديد درجة شدة بعض العيوب كالهطول او ابعاد،اطوال لمعرفة .التموجات ويمكن استخدام االجهزة المساحية الحديثة لتحديد بعض هذه المتطلبات للطبقة السطحية (core testعينات اسطوانية من التبليط االسفلتي بجهاز اللباب االسطواني ) (01)تم اخذ -2 المواصفات فحص السمك، الكثافة ونسبة الدك ، فحص ثبات مارشال، االنسياب ..الخ وحسب ألجراءوذلك كل فحص.ازاء المبينة .extraction test))االستخالصألجراء فحص مواقعمن نفس العينات من تبليط الطبقة السطحية (01)أخذ-0 :ا": البرنامج العمليرابع شارع الطهمازية وهو شارع رئيسي داخلي في مركز مدينة الحلة ويربطها بقرية جزء من تم تقييم حالة التبليط في هالتبليط في عيوب لوضوحم (7( كم وعرض)0دراسة المسار االيمن للشارع بطول) ( اذ تم07)صوره رقم الطهمازية تم بعد ذلك تحديد اسباب ظهور هذه و ( والطريقة التقليدية pciطريقة معامل حالة التبليط )ب عيوبالتقييم وتم وكما يلي: العيوب وافضل االساليب لمعالجتها او التقليل من ظهورها، ونعرض باختصار آلية العمل االمريكية طريقة المواصفاتذكرت هذه ال(: pavement condition index)التبليط حالة معامل طريقة-0 بمايلي: وتتلخص التبليط عيوب تحديدل حديثا استخدمتو (pci)ال طريقة وتسمى [astm d5623, 2006]الرقم ( 0في الجدول رقم )لهذه الطريقة والمذكورة ادناه في استمارة التقييم الموقعي (01معرفة العيوب القياسية ال) -أ ان كانت )عالية , متوسطة او واطئة( وحسب الصور القياسية بالمواصفات لكل عيب شدتها ومعرفة درجة بالسير على التبليط الكشف الموقعي حدوثه وطريقة قياسه ثم تم بعد ذلك اجراء مع مواصفاته واسباب واستخدام اطوالها في قطاعات التبليط وتصويرها مساحاتها اوقياس و عن قرب التبليط لتدوين انواع عيوب . ادناه( 2)و( 0) رقم الموقعي وكما في جداول الكشفمسطره معدنية لقياس ارتفاع الهبوط أو التخدد حسب اآللية الموضحة في (pavement condition index)( ايpciحساب قيمة معامل حالة التبليط ) –ب مقطع مساحة الى مساحته نسبة من عيب كل كثافة بايجاد ادناه(0)رقم الجدول في العيوب تقييم استمارة ألي عيب بواسطة منحنيات(deduct value) عرضه( وايجاد قيمة الخصم× التبليط )طول الطريق االفقي المقياس على الكثافة قيمة بتحديد( 1رقم الشكل) النموذج في وكما عيب لكل القياسية المواصفات .على درجة شدة العيب بالمنحني لنحصل على قيمة الخصم على المقياس العمودي تسقيطهاو للمنحني 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 02 يتم تصحيح مجموع قيم الخصم للعيوب في اي قطاع بواسطة منحني المواصفات الخاص بذلك والمرفق –ت فيتم (7كانت العيوب) فاذا( 0والخاص بالقطاع الذي تزيد عيوبه عن)( 8)الشكل رقم البحث في نهاية ان ( حيثq=2) حني على منحنيلمحددة على المقياس االفقي للمنابتسقيط القيمة الخصم قيمة حيتصح (q=7-5=2 ) ادناه( 0)رقم جدولنموذج في وكما العمودي المقياس على المصححة القيمةلنحصل على. ( وكما في استمارة011( من خالل طرح قيمة الخصم الكلية المصححة من الرقم)pciيتم حساب قيمة ) -ث ( ادناه.0التقييم بجدول رقم ) ( pci)ال قيمة خالل من( 0كما في الجدول رقم) ضعيف او جيداذا كان المقطع تبليط حالة يدحدت -ح حددت وبذلك ،ادناه(4)رقم الجدول في وكما الطريقة هذه مواصفاتفي (pci)ال قيم بجدولومقارنتها .مختبري فحص اي وبدون التبليط وحالةوكمياتها ودرجة شدتها لعيوبالطريقة انواع امواصفات هذه وحدات قياس المساحات بالقدم المربع عدا ستة منها pci): تحدد طريقة ال)طريقة قياس العيوب ووحداتها الشقوق ،شقوق انعكاس المفاصل ،شقوق الحافات ،قاس بالقدم طول وهي عيوب: التقعر والتحدبتخمسة الطولية والعرضية وانخفاض الكتف عن التبليط اما السادسة فهي الحفر وتقاس بالعدد وذلك ألن قيم المنحنيات تحديدها ويمكنادوات القياس هي الشريط والمسطرة المعدنية كما ورد بالمواصفات المستخدمة هي بوحدات القدم. [astm d5623,2006]. ةالحديث المساحية والمعدات االجهزة باستخدام اكثر بدقة (:pciتحديد العيوب موقعيا بطريقة معامل حالة التبليط) التبليط عيوب نواعأل( م طول ثم تدوين المعلومات الموقعية 011تم تقسيم الطريق المذكور الى قطاعات كل) ( ادناه. 0مبين بالجدول رقم )ال( م 011جزء من تبليط للطريق بطول ) وادراجها في جداول الكشف وكما في لطول التبليط لقطاعات ( م011كل )لفي جداول الكشف الموقعي المدونةهذه المعلومات الموقعية تم توحيد شدة( كم وكانت نتائج انواع وكميات ودرجة 0كل )بحيث تدون وادراجها باختصارها( كم 0الطريق البالغ ) ( ادناه. 2عيوب التبليط كما في الجدول رقم) )استمارة الكشف ( لكل قطاع وحسب جداول الكشف وكما مبين في نموذج الحساباتpciحساب قيم ال ) -ب (.0( كم وكما في الجدول رقم)0لكل) (pci)، ولالختصار تم ايجاد معدل ال(ادناه 0في الجدول رقم )الموقعي( . ادناه (0المواصفات القياسية وكما مبين في الجدول رقم)ب( مع القيم pciبمقارنة قيم ال) ايجاد حالة التبليط -ج 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 05 :الطريقة التقليدية -1 طة المرجعية لالمعلومات التصميمية للخ وذلك من معرفةبواسطة الفحوص المختبرية حالة التبليط وتعتمد على تحديد االسفلتية للطبقة( core testلباب االسطواني )نماذج التبليط االسفلتي بفحص الوفحص للتبليط وينتهي( 41) شارع تقاطع من يبدأ والذي سنوات( 01)من اكثر قبل انشائه تم الذي الطهمازية لطريق السطحية .تحديد حالة التبليط واسباب الخلل فيهلطة المرجعية لاالختبارات المختلفة ومقارنتها بالخ أجراءب الطهمازيه بقرية : طة االسفلتية المرجعيةلفحوصات الخأ( تدرج من( reference job mix design) المرجعية الخرسانية االسفلت طةلخ تصميم او معادلة معرفة تم ركام الخلطة وخواصه الفيزيائية، خواص المادة المالئة، الخواص الفيزيائية ألسفلت الخلطة وكذلك قوة ثبات مارشال وهو ادناه( 00والجدول رقم ) (1 3)رقم الجداول في والفراغات الهوائية ...الخ وكما مدرجةللخلطة ، االنسياب والمعتمدة من قبل aashto)وال)astm) التصميم المعتمد من رب العمل)بلدية الحلة( وهي حسب مواصفات) من هذه الفحوص. فحص كل ازاء والمبينة (2110) لعام (sorb/r9الطرق والجسور ) :ب( فحوصات نماذج االسفلت الموقعية ( م طول في 011بحيث اخذ نموذج لكل مسافة )( (core testتم اختيار مواقع اجراء فحص اللباب االسطواني ( والذي تشترط اخذ ماال يقل عن aashto t168تبليط الطريق وهي تفي بمتطلبات المواصفة االمريكية ) ( كم 0لطول الطريق البالغ) اذج غير مخلخله(نم01ماذج فحص اللباب)نموذجين لكل كيلومتر وبذلك بلغ عدد ن ( م ، تم طالء نماذج اللباب بشمع البارافين ليؤخذ الوزن النوعي وهي مطلية ومعلقة بالهواء ووزنها النوعي 7وعرضه) وكما يلي: المعتمدة من قبل الطرق والجسور الفحوصات نماذجلل اجريتوهي مطلية ومعلقة بالماء و (varnerقياس سمك طبقة االسفلت السطحية: وذلك بقياس ارتفاع النماذج بواسطة القدمة ذات الورنية ) – 0 ( سم ايضا.01باب هو)ل( سم وان قطر نموذج ال01علما بان سمك الطبقة التصميمي هو ) العظمى الكثافة وان (aashto t166 -74) حسب المواصفة الفحص: تم حدلفحص الكثافة ونسبة ال -0 (.01، النتائج في الجدول رقم)%(منها13في النماذج الموقعية عن) حدلنسبة الان ال تقل و 0(غم/سم2.00) وذلك بغمر نماذج اللباب الموقعية بحوض مائي بدرجة(: flowفحص ثبات مارشال ونسبة االنسياب ) 0 (flow) قيمة ثبات مارشال ومقدار االنسياب ( ساعة ثم فحصها بجهاز مارشال لمعرفة24( ْم ولمدة )31) . ( ادناه02وكما في الجدول رقم) ( والمذكورة اعالهastm d1559لكل نموذج وحسب المواصفة ) اللباب حفر وذلك بتوسيع( نماذج جديدة 01: حيث تم اخذ )( extraction testاجراء فحص االستخالص) –ج وبعناية للمحافظة على مكوناتها هاركامويتأثر بالجهاز قصلم تاسفلت خلطة للحصول على لنفس المواقع النماذج بالسبرتو االبيض وهي مغطاة لكي تتفكك وتكون جاهزة نقعت بشكل ادق ثمعلى نتائج التدرج وللحصول 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 00 نموذج وجففلمعرفة تدرجه تهوغربل هفيجفتم تالركام نظيف تماما وعندما اصبح الفحص بجهاز تغسلثم للفحص ( ْم ومنه تم ايجاد نسبة االسفلت 001 -011معروف الوزن بالفرن المهوى بدرجة)الممزوج باألسفلت سبرتو من ال والتينتائج البين ي( ادناه 00الجدول رقم ) .مكونات الخلطة االسفلتية من تدرج الركام ونسبتهباقي وكذلك تم ايجاد المناخل من العابر في واضح بشكل وظهر الناعم الركام تدرج في العابر نسبة في نقص وجود تبين ( 3نسبة االسفلت وذلك عند مقارنتها بمواصفات جدول رقم) في وكذلك( 211)و(01)،(8)رقم [khanna, 1991]و [haung ,2004]،1985]،محمود [،[ iraqi spe.,2003]. المرجعية االسفلت لخلطة : المناقشة ":خامسا :يلي ما نجد ادناه ( 00 -0من) العيوب وصور (7-0)رقم من واالشكال( 00 -0)رقم الجداول مالحظة بعد ( هي 2(: نالحظ ان عيوب التبليط التي دونت في الجدول رقم)pciتحديد عيوب وحالة التبليط بطريقة ال) -0 ( عيوب وبمساحات واطوال ودرجات شدة مختلفة وكما يلي:8) الشقوق كانت حيث الطريق تبليط مساحة من%( 1.403)نسبتها بلغت اذ مساحة العيوب اكثر وهي: الشقوق(أ من%( 1.082%( والمتوسطة الشدة بنسبة )1.000العالية الشدة بنسبة ) alligator cracking)التمساحية ) الشدة بنسبة ( فكانت عالية longitudinal & transverse crackingوالشقوق الطولية والعرضية) التبليط مساحة اما التمساحية)االعياء( هو االحمال المتكررة ونشوء جهد واجهاد في اسفل التبليط %(. ان اسباب الشقوق 1.010) في نكماش احصول وأالشقوق الطولية والعرضية فتحدث بسبب الضعف االنشائي لعمل مفاصل مسارات التبليط astm d1559,2006].]تحت التبليط االسفلتياذا كان اثناء الدورة الحرارية صلبالخرساني ال التبليط %( من 1.227(: يحتل الدرجة الثانية من حيث الكثافة حيث ان نسبته في التبليط هي)depressionالهبوط ) ( أ %( من مساحة التبليط والمتوسطة الشدة 1.047مساحة تبليط الطريق حيث ان نسبة العالية الشدة منها هي ) وقلة ( االساس الترابي للطريق لرداءة تنفيذ طبقاته settlementان اسباب ظهوره هو نزول)و %( 1.18بنسبة) . المستخدمة فيها وهي اسباب تعود لمخالفة مواصفات العملوعدم جودة المواد حدلها (:تحتل الدرجة الثالثة من حيث كثافة حيث ان نسبتها في التبليط هي corrugationsالتموجات)-ب %(من مساحة التبليط والمتوسطة 1.10%(من مساحة تبليط الطريق حيث بلغت العالية الشدة نسبة)1.220) تالصق الطبقة ان ظهور التموجات يعود لتأثير حركة مرور المركبات وعدم ثبات، %(1.010الشدة بنسبة) الدوران أو عند بدء الحركة. او السطحية او االساس في التبليط فيتجمع التبليط تحت العجالت عند التوقف هي ( : يأتي بالدرجة الرابعة من حيث كثافته في التبليط حيث ان نسبته في التبليط ruttingالتخدد)-ت والمتوسطة %( من مساحة التبليط 1.107العالية الشدة منه بلغت نسبته )و %(من مساحة التبليط 1.030) طبقات التبليط السفلى بسبب consolidation)) انضمام ظهوره الى%( ويعود سبب 1.043الشدة بنسبة ) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 02 ه.حدلقلة وضعف خلطته و احمال المركبات وحصول ازاحه وتشوه دائمي في تبليط الطريق لرداءة مواده %(من مساحة التبليط ، 1.100( وكثافته المتوسطة الشدة هي)polished aggregateتآكل ركام التبليط) -ح كفاءة د سبب ظهوره الى تآكل الركام بسبب استمرار االحتكاك بينه وبين عجالت المركبات المارة وعدمويعو .(abrasion testالركام في مقاومة ذلك اي)عدم كفاءته في فحص التآكل الميكانيكي _ وكثافته%( 1.123الشدة هي) عالية(: كثافته الweathering and ravelingتفكك السطح والتجويه) -ج المادة الخلطة لقلة ويعود سبب ظهوره الى قلة ترابط التبليط مساحةمن %(1.128المتوسطة الشدة) من تماسكه ، عدم الخلط رداءة الركام وعدم نظافته مما يقلل ،تلفه بالحرارة العالية ،االسفلت الرابطة اي او اي عدم مطابقة الخلطة للمواصفات رش الخلطة االسفلتية وحصول بعض التصلب فيها ف الجيد وتأخر .في اماكن محدودة وتلفه التبليط تفكك الى ؤديي مما التبليطالبترول على مشتقات سقوط بعض ا من مساحة التبليط ، ويعود سبب ظهوره %(1.110( : كثافتها المتوسطة الشدة هي)potholesالحفر) -خ بسطحه او حصول الى حصول تلف في التبليط بسبب ضعف الخلط االسفلتية او حصول تفكك محدود واستمرار المناسبة بالسرعة اصالحها عدم عند الحفر هذه وتكبر تنمو ثم الشدة عالية تمساحية شقوق [astm d5623,2006] االسبابمصدر مرور المركبات عليها وتأثرها بالظروف الجوية المحيطة بالتبليط. (:الفحوصات)التقليدية بالطريقة التبليط وحالة عيوب تحديد -2 الحرص تم والذي المكان بنفس التبليط حفر ونماذج اللباب لنماذج المختبرية الفحوصات خالل من تبين حيود بالنقص بأن هناك( للتبليط في موقع العمل representativeممثلة) هاان تكون نماذج على االمكان قدر ( في كل ما يلي:003طة المرجعية وكما نالحظ ذلك في الجداول من رقم )لعن مواصفات الخ وان نسبة( ملم 01 – 4يتراوح من )بمقدار سم (01والبالغ ) يعن السمك التصميم التبليط سمكينقص -أ بالسمك الموقعي وهو اكثر من السماحاقل من السمك التصميمي وهي (% 01.1 –4.1النقص تتراوح من) . ادناه (01)رقم الجدول نتائج في وكما (r9/sorb( ملم كما حددته مواصفة الطرق والجسور )0) 0( غم/سم2.00اي اقل من الكثافة المرجعية البالغة) 0(غم/سم2.28 –2.04كثافة التبليط تتراوح من ) -ب اي ان نسبة الحدل في بعض(% من الكثافة المرجعية 18.7–12.34اي ان نسبة الحدل كانت تتراوح من) . ادناه (01)رقم الجدول نتائج في وكما %(13الحدل المطلوبة وهي) نسبة من اقل( كم 2لتبليط ) النماذج kn(01.1 – 1.40تتراوح من)الذي نتائج ثبات مارشال في المطابقة عدم اللباب فحص نتائج اظهرت -ت تائج وان ن (%00.20 – 01.10بنسبة تتراوح من) kn( 00.8اي اقل من قيمة الثبات المرجعي البالغة) بنسبة ( ملم2.70االنسياب المرجعي البالغة) ( ملم اي اقل من قيمة2.4 – 2.00االنسياب تتراوح من ) .ادناه( 02)رقم الجدولنتائج فيوكما (%02.72 – 22.04تتراوح من) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 02 % اي اقل (4.30-4.20)نتائج نسبة االسفلت تتراوح منان التبليط حفر اظهرت نتائج فحص نماذج -ث وكما (%7.1 – 00.1(%من وزن الخلطة بنسبة تتراوح من )0.1) من نسبة االسفلت المرجعية البالغة .ادناه( 00)رقم الجدول في (، 01(،)8،)(4للمناخل رقم)للعابر التدرجات الناعمة خلطة التبليط في وجود حيود بالنقص في تدرج ركام -ج .وهذه النتائج تدعم اسباب العيوب المذكورة اعاله( 00)رقم الجدول في وكما مختلفة بنسب( 211و) :ا": معالجة عيوب التبليطسادس :هما رئيسيتين مرحلتين الى المعالجة هذه تنقسم ولتوضيح ذلك نذكر ما يلي: ، المعالجة عند ظهور العيوب بالتبليط( المعالجة عند تصميم التبليط ب( أ احصائيات المركبات وانواعها واحمالها وتطورها المستقبلي وعدم دقة:نظرا لعدم المعالجة عند تصميم التبليطأ( قامتمن البلدان بشكل تام وتغير الظروف الجوية غير المتوقع فأن كثير ن التبليط عتصريف مياه االمطار وهي ما تحت االساس وطبقة التدرج تحت ما تربة طبقة بين البالستيكي( geogrid)ال شبكم من طبقة وضعب االسفلت طبقةأما عند انشاء للطبقات السفلى للطريق.استخدامها لذا ينبغيمواد تسليحية اثبتت نجاحها في التقوية االضافية التبليط طبقة وكذلك الفوالذي شبكمال من طبقة باستخدام هاتسليح ينبغيف الرابطة او السطحية [qian et al.,2010 [،] baek et al.,2003]حيث اثبت انه فعاال في تقليل االجهاد وتأخير التشققات. عند الصيانة ويستخدم بالمعالجة: العيوب الواردة بالبحث ودرجة شدتها انواعوحسب :بالتبليط العيوب ظهور عند المعالجة(ب رملية( طبقة سطحية 2: وهي االسفلت السائل المذاب بالماء)مستحلب(. (fog seal) رذاذيه( طبقة سطحية 0 ((sand seal 0: وهي االسفلت السائل مع الرمل الخشن) (طبقة سطحية رقيقةchip seal:) وهي االسفلت على ان تتم هذه asphalt overlay)(اضافة طبقة اسفلتيه سطحية حاره)4السائل مع الرمل والحصى الناعم. االعمال بشكل نظامي فمثال عند ازالة جزء من التبليط فيتم تحديد وقص ذلك الجزء بماكنة القص ثم تصليح ثم فرش طبقة االسفلت االضافية بالخلطةtack coat) وحدل الطبقة السفلى المتضررة ، رشها بأسفلت اللصق) :الحارة وحدلها بحيث تكون جميع هذه الفعاليات مطابقة للمواصفات المعتمدة ، لذا تتم معالجة العيوب كما يلي ترشو المضغوط بالهواءالشقوق المتوسطة الشدة تنظف وهي بدرجتين متوسطة وعالية الشدة حيث :الشقوق(أ لتكوين خلطة (sand sealتستخدم الطبقة الرملية)واحيانا للشقوق ( لغلقfog sealباألسفلت الرذاذي) الطبقة السطحية فرش يجب( ملم ف70اكبر من)عرضها اما الشقوق عالية الشدة و رغوية تحقن داخل الشقوق (.overlayواحيانا تضاف طبقة اسفلتية) الشقوق وتكسو تملئ لكي (chip seal )الناعم والحصى بالرمل ساخنه اسفلتيةطبقة اضافة فيتم ملم (01)عن ضااالنخف يزيد ال حيثالشدة متوسطال الهبوط في: الهبوطب( 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 01 فيتم ازالة تبليط والذي ينخفض بأكثر من ذلك بالهبوط عالي الشدهوتهيئة سطح التبليط لذلك اما تنظيف بعد طبقات التبليط بشكل نظامي. عملعادة اطبقة ما تحت التدرج و صالحوا الجزء الهابط من أكثر التي ال تؤثر على حركة المركبات اما اذا كان ارتفاع التموج )التعرج(التموجات التموجات: تهمل ت( في ، أما ة الحار يةاالسفلتالسطحية الرملية واحيانا تستخدم الطبقة طبقةال رشتف ثم التموج قشط فيتمملم (01) وما تحتها ثم االساس من التموجات فيتم ازالة الطبقة السطحية المتضررة واصالح تلف طبقةالدرجة العالية .نظامي وبشكلوفرش الطبقة االسفلتية السطحية الحارة التبليطبقات ط عمل اعادة وتفرش طبقة االسفلت بالهواء التخدد فيفيتم تنظ ملم(20عن) ال يزيد عمقهالشده الذي المتوسط التخدد:ث( اصولي.بشكل و بخلطة اسفلتية حاره ملئهفيتم ملم (20)اكثر من بعمقو عالي الشدة اما ال يةلرملالسطحية ا الرذاذية ةسفلتياالبطبقة المتوسط الشدة يرش و ال يؤثر على حركة المركبات الذي التآكليهمل الركام:( تآكل ج ية.الرملاالسفلتية سطحيةال طبقةال فتضاف اما التآكل عالي الشدة اما اذا مع الرمل والحصى السطحية طبقةالاضافة يتم التآكل المتوسط الشدة ( تآكل سطح التبليط والتجوية:ح فيتم سم (00وعمق اقل من)سم (01بقطر اقل من)ادى الى حفر تفكك التبليط و عالية الشدةدرجة كانت االبعاد من اكثرتفكك ال واذا كان بخلطة اسفلتية حارة بشكل نظامي وملئه وتنظيفهزالة التبليط الضعيف ا .(00وتعالج حسب درجة شدتها وكما نالحظ ذلك في جدول المواصفات رقم) الحفر من فيعتبر المذكورة قص حافات الحفرة يتم سم ف (40وقطرها عن) سم( 0)عن والتي ال يزيد عمقها الشدة متوسطةال ( الحفر:خ 2005] ، دوره [و[flex.pav,2013] ،]1122،ابو عوده[.نظامي بشكلو حارة اسفلتية بخلطةوملئها وتنظيفها :االستنتاجات والتوصيات ا":سابع ذكرته قياسي عيب( 01) اصل من االسفلتي التبليط في عيوب( 8) تحديد تم( pci) ال طريقة باستخدام -0 ،ان الشقوق التمساحية هي اكثر العيوب كثافة بالتبليط ثم الهبوط(و 00-0وكما في الصور رقم) الطريقة هذه وان اسبابها رداءة مواد التبليط وسوء تنفيذها. في التبليطكثافة باقي العيوب فهي اقل التموجات، التخدد اما الى عدم ن اسباب هذه العيوب ترجع بأالطريقة التقليدية تبين عند استخدام الفحوصات المختبرية والخاصة ب-2 االسفلتية بالمعمل حسب تصميم الخلطة المرجعية باإلضافة الى مخالفة المواصفات اثناء تنفيذ لطةتجهيز الخ قاوم االحمال المتكررة والحركة.تطبقاته وعدم تالصقها ل االعمال موقعيا بقلة سمك التبليط وقلة حدل حيث هناك تماثل او تطابق في تحديد حالة تبليط الطريق رغم االختالف في اسلوب التعبير في الطريقتين -0 بحصول اجهاد في التبليط بسبب احمالبالمناقشة (pciطريقة ال)مواصفات ان اسباب العيوب التي ذكرتها طبقة االسفلتحدل ل جيد ، قلة سمك و بشك هاعدم تالصقرداءة مواد طبقات الطريق المركبات والحرارة، 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 01 كما نالحظ بالجدول هي ذاتها االسباب الذي دلت عليها نتائج الفحوصات المختبرية ونزول طبقات الطريق نسبة االسفلت و ، االنسياب الثبات وقلة والتدرج، حدلال،السمك مخالفة المواصفات في من( ذلك 04رقم ) .وقلة مقاومتها لألحمال االسفلت وسوء تنفيذها الموقعيخلطة على ضعف تدل وهيعن الخلطة التصميمية أظهرت(pciضعيفة بطريقة ال) تبليطهاان القطاعات الذي كانت حالة اعاله بنفس الجدول المذكور ظهر ( ب وانها تقل عن متطلبات الخلطة اكبر مقدارالفحوصات المختبرية بالطريقة التقليدية مخالفتها للمواصفات ب لذا نوصي بما يلي: ،وهذا تطابق في تحديد االسباب بين الطريقتينالتصميمية اكثر من القطاعات االخرى لمعرفة اسباب العيوب ( لتحديد اسباب عيوب التبليط قبل القيام بأعمال الصيانة pci( باستخدام طريقة ال)0 اثبتت كفائتها في هذا المجال.(pci)حيث ان مواصفات في الفحوصات ة والجهد والوقت لتجنب هدر الكلف سواق المحلية لطبقة االسفلت عندالمتوفر باأل فوالذيشبك المطة االسفلتية كاللاستخدام مواد التسليح للخ (2 ما بين طبقة ما (geogridشبك البالستيكي ال)لمانشائها او لطبقة االسفلت االضافية عند الصيانة وكذلك ا .تحت التدرج وما تحت االساس حيث اثبتت البحوث فعالية استخدامهما لحماية وتقوية طبقات الطريق : ثامنا": المصادر *1-astm d5623,2006. "standards practice for roads and parking lots pavement condition index surveys". al-qadi i.l. and appea a.k.2003.”eigthyears of field performance of a4 -2 secondary road incorporating geosynthetics at the subgradebase interface". board annual meeting, pp 1-3. transportation research 3-baek, j. and i.l. al – qadi,2006.”effectiveness of steel reinforcing interlayer highway system on delaying reflective cracking”, proceedings of airfield and pavement meeting today’s challenges with emerging technologies, asce. baek j.,wang h.,2003.”longlasting pavement structure rehabilitation: hot-4 mix asphalt overlay with steel reinforcement netting interlayer system”,faa design competition for universities 2007 – 2008 academic year,department . of transportation washington ,d.c 5-elseifi,m. and i.l. al – qadi,2003.”effectiveness of steel reinforcing netting in combating fatigue cracking in new flexible pavement systems". journal of 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 01 transportation engineering, asce,vol.131. 6-fannin r.j. and sigurdsson o.,1996.”field observation on stabilization of unpaved roads with geosynthetics.”asce,journal of geotechnical engineering . vol.122,no.7,pp.544553 7flexible pavement distresses 2013. www.google.com. -hufenus r.,rueegger r.,banjac r.,mayor p.,springman s.m. and bronnimann8 r.,2005.”full scale field tests on geosynthetic reinforced unpaved roads on soft subgrade". geotextiles and geomembranes 24 (1), pp.21-37. 9-huang,y.h.,2004."pavement analysis and design",2nd edition, prentice hall englewood cliffs,new jersey. 10-iraqi general specification for roads and bridges ,(2003)."standard specification for roads and bridges". the state corporation for roads and bridges(rev. edi.) lee,s.j., 2008."mechanical performance and crack retardation study of a fiber-11 glass gridreinforced asphalt concrete system",nrc research press, canada. 12khanna, s.k. and c.e.g justo,1991." highway engineering"7th edition new chand, india. montepara a.,tebaldi g. and costa a.,2005.”performance evaluation of a sur-13 -face pavement steel reinforcement “,proceedings of the 5th intrnational con -ference on road & airfield pavement technology(icpt).seoul,korea. 14-palmeira e.m. and antunes l.g.s.,2010.”large scale tests on geosynthetic reinforced unpaved roads subjected to surface maintenance”. geotextiles 28.2 pp.547-558,2010,, and geomembranes 15qian y.,han j.,pokharel s.k. and parsons r.l.,2010.”experimental study on triaxial geogrid– reinforced bases over weak subgrade under cyclic loading". . asce ,conference proceeding paper,pp.1208-12015 16-tang x.,chehab g.r. and paomino a.m.,2008.”accelerated testing of geogrid reinforced subgrade in flexible pavement”. asce, conference 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 01 proceeding paper,pp.1049 -1055. 17-turkey, ibrahim al-suliman, sultan h. al-kufaili, adnan m.al-shiab,2005. "road distresses in dubai emirate". dubai municipality magazine for researches . 18-vacri m.,2007.”reinforcement with double twist steel wire mesh: modeling and laboratory experiences to evaluate the design life improvement of asphalt international s11v conference,palermo,italy. pavements”,4th 19-shixiu, mo and lingyun kong, 2012." a study on the determination method of the rut deduct value in the asphalt pavement condition index" research, china (www.google.com.ivsl). .العربي المجتمع مكتبة". الطرق هندسة"كتاب. 2100 حسين احمد ،المهندس عودة ابو -21 .دبي بلدية". الطرق صيانة"كتاب .2110دورة -20 الجامعيةجامعة بيروت. دار الكتب -كتاب" هندسة الطرق". كلية الهندسة1985.محمود، توفيق سالم –22 (hyder consulting)العالمي البريطاني للمكتب" ممثال ابوظبي واشغال لبلدية استشاري مقيم عمل وان سبق الباحث* ( 011+ 1 – 11+ 1) من للطريق االيمن الجانب من لجزء التبليط لعيوب الموقعي الكشف(: 0) رقم جدول العيوب الموقع وتوصيفها انواع العيوب 1 +11 / 1 +011 شقوق تمساحية طولية شقوق هبوط تموجات وعرضية تآكل التخدد حفر الركام 2قدم 2قدم 2قدم طول مقد 2قدم 2قدم 2قدم الوحدة 021 43 0 28 02 03 04 الكمية متوسط متوسط متوسط متوسط عالي عالي متوسط درجة الشدة *الطريق تبليط لعيوبالموحد الموقعي الكشف نتائج(: 2) رقم جدول المقطع )كم( وصف العيوب انواع العيوب شقوق تمساحية شقوق طولية التخدد هبوط تموجات وعرضية تفكك حفر السطح تآكل الركام 2قدم 2قدم عدد طول م قد 2قدم 2قدم 2قدم 2قدم الوحدة 1+ 11 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 01 / 11 +0 30 4 87 230 017 202 233 الكمية متوسط متوسط عالي متوسط عالي متوسط متوسط الشدة 11 +0/ 11 +2 70 020 013 208 074 220 الكمية متوسط عالي متوسط متوسط متوسط عالي الشدة 11 +2/ 11 +0 41 010 7 02 87 000 270 الكمية متوسط عالي متوسط متوسط متوسط عالي عالي الشدة 11 +0/ 11 +4 4 040 30 070 000 080 الكمية متوسط عالي عالي عالي متوسط متوسط الشدة 11 +4/ 11 +0 00 011 00 002 083 078 203 الكمية متوسط متوسط عالي متوسط عالي متوسط متوسط الشدة 2قدم 0.4422.1 =01.7084×7×0111 = م (7وعرض)( كم 1لطول) مساحة التبليطعلى مساحته)كثافتة( بالتبليط بتقسيم نسبة العيب* تم حساب ( الفرع : جزء من الجانب االيمن للطريقpci(: استمارة التقييم الموقعي لالسفلت إليجاد قيمة ال)0جدول رقم ) 2مسحت بواسطة :.... وحدة النموذج: قدم 2014/االيمن التاريخ: ....../100+0) -00 +0القطاع : كم) انواع العيوب (03) االندفاع -ج surface defects العيوب السطحية: (08)االنتفاخ -ح (2)النضح -أ cracking: التشقق (1)انخفاض الكتف/ المسار -ب (0) تمساحية –أ (02)تآكل الركام -ت (0)بلوكيه -ب (00)الحفر -ث (7)الحافات -ت (04)تقاطع سكك الحديد -ج (8)انعكاس المفاصل -ث (01)تفكك السطح والتجويه -ح (01) الطولية والعرضية -ج surface deformation:تشوه السطح (07) المنزلقة -ح (4) البروزات والتحدبات -أ patching:الترقيع (0) التموجات -ب (00) الترقيع وترقيع قطع الخدمات (3)الهبوط -ت (00) التخدد -ث المخطط: مساحة المقطع: .×100×10.7584 2قدم 7530.88= نواع العيوب 24 20 21 21 6 5 1 النوع 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 22 م 24 م 2 م 211 م 28 ع 12 ع 16 م 14 الكمية والشدة متوسط )م( عالي )ع( 22 28 211 2 24 24 21 pciحسابات قيمة ال قيمة الخصم الشدة % الكثافة نوع العيب cor.ded.v -100 = pci 47.5 100 = 52.50 = حالة التبليط = متوسط الى استنادا أدناه (4حسب الجدول رقم) [astm d5623,2006 ] 9.0 م 1.284 1 19.4 ع 0.212 5 12.25 ع 0.159 6 3.0 م 0.371 21 1 م 2.490 21 1.. م 1.120 20 14.0 م 1.42 24 total deduct val. 64.65))مجموع الخصم 2..4 (cor.ded.v)قيمة الخصم المصححة (astm d5623,2006)ال مواصفات وحسب pciال قيمة حسب التبليط حالة مواصفات :(4)رقم جدول الطريق تبليط حالة pci ال قيمة حدود الطريق تبليط حالة pci ال قيمة حدود ت جيد 71 00 فاشل 01 1 0 جيد جدا 80 71 "جدا ضعيف 20 01 2 ممتاز 011 80 ضعيف 41 20 0 متوسط 00 41 4 pciال قيم حسابات نتائج معدل حسب الطريق محطات تبليط حالة يبين(: 0)رقم جدول الطريق تبليط حالة pci ال قيم معدل عدد القطاعات (كم) الطريق محطات ت متوسط 01.23 10 0+ 11 11 0 متوسط 43.07 01 2+ 11 – 0+ 11 2 ضعيف 01.00 01 0+ 11 2+ 11 0 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 25 ضعيف 02.40 01 4+ 11 – 0+ 11 4 متوسط 42.7 01 0+ 11 – 4+ 11 0 (r9/sorbطة االسفلتية للطبقة السطحية المرجعية وحسب مواصفة )ل(: تدرج ركام الخ3جدول رقم) حجم المنخل فتحة المنخل )ملم( نسبة العابر المستخدمة الكلي % بالنسبة للوزن مواصفة نسبة العابر بالنسبة للوزن الكلي)الركام + المادة المالئة( % 4/0 01 011 011 2/0 12.5 10 100 – 90 8/0 9.5 80 90 – 76 44 74 08 4.75 4رقم 28 – 58 40 2.36 8رقم 5 21 00 0.3 01رقم 4 10 3 0.075 211رقم المرجعية)حصى النباعي( طةلبالخ (: الخواص الفيزيائية للركام المستعمل7جدول رقم ) مواصفة الفحص الركام الناعم الركام الخشن الخاصية astm c127& 128 2.32 2.48 الوزن النوعي االقصى = 2.37 2.61 النوعي الظاهري الوزن = 1.00 1.40 نسبة امتصاص الماء % astm c131 7.0 نسبة التآكل )لوس انجلس( ( r9/sorbطة المرجعية)مواصفة الطرقلالخواص الفيزيائية لإلسفلت السمنتي في الخ (:8جدول رقم) رقم فحص الخاصية aashto نتيجة الفحص الوحدة b(01-41)لل حدود المواصفات 01 41 43 ملم t 49 0/01 ثانيه 0،غم 011 ،مْ (20االختراق في درجة ) 32 – 00 00 مْ t 53 (r&b) درجة الليونة 011< 013 سم t 51 سم/ دقيقة 0ْم, (20درجة )ب االستطالة 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 20 241< 230 مْ c.o.c t 48)درجة االتقاد ) t % 010 >11 44 الذوبان في محلول تراي كلورو اثلين r9/sorbوحسب المواصفة طة االسفلتية للطبقة السطحية المرجعيةالخل( : خواص 1جدول رقم) حدود المواصفة تصميم الخلطة الفحص 2.31 (0الكثافة العظمى )غم/سم astm d1559 00.8 ≥ 8) ) (kn ) ثبات مارشال 4 -2 2.75 مارشال)ملم( flow )انسياب) 0 – 0 4.00 طة %لالفراغات في الخ 04 ≤ 00.70 الفراغات في الركام 65 85 70.30 % الفراغات المملوءة باألسفلت 7 – 4 0 نسبة محتوى االسفلت % ( : نتائج الفحوصات الفيزيائية لنماذج اللباب االسطواني االسفلتية في محطات الطريق01الجدول رقم ) رقم النموذج المحطة )كم( الموقعي نوع الفحص الحدل %نسبة (0)غم/سمالكثافة )سم(السمك 11 – 11 +1.0 a1 9.95 2.27 98.26 11 +1.0 – 11 +0.11 a2 9.90 2.25 17.41 11 +0.1 – 11 +0.0 a3 9.94 2.20 10.37 11 +0.0 – 11 +2.1 a4 9.92 2.22 13.01 11 +2.1 – 11 +2.0 a5 9.91 2.03 10.01 11 +2.0 – 11 +0.1 a6 9.93 2.07 10.10 11 +0.1 – 11 +0.0 a7 9.94 2.08 14.07 11 +0.0 – 11 +4.1 a8 9.95 2.04 12.34 11 +4.1 – 11 +4.0 a9 9.96 2.23 17.80 11 +4.0 – 11 +0.1 a10 9.93 2.28 18.71 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 22 (aashto t 90 -70)(المرجعية )السمنت ( حسب المواصفةfiller(: خواص المادة المالئة)00جدول رقم) المواصفة حد النتيجة الخاصية حد المواصفة النتيجة الخاصية 3.1 النوعي الوزن 011 011 ملم(1.3)حجم منخل من المار نسبة 011 11 011 ملم(1.08)حجم منخل من المار نسبة 011 30 95 ملم(1.170)حجم منخل من المار نسبة الطريق محطات في االسطواني اللباب لنماذج االسفلتية طةلالخ فحوصات نتائج( : 02) رقم جدول (ملم()flow)االنسياب (kn)مارشال ثبات قوة النموذج رقم (كم) المحطة 11 – 11 +1.0 a1 01 2.4 11 +1.0 – 11 +0.11 a2 9.95 2.35 11 +0.1 – 11 +0.0 a3 1.80 2.3 11 +0.0 – 11 +2.1 a4 1.72 2.25 11 +2.1 – 11 +2.0 a5 9.65 2.17 11 +2.0 – 11 +0.1 a6 9.5 2.00 11 +0.1 – 11 +0.0 a7 9.45 2.13 11 +0.0 – 11 +4.1 a8 9.52 2.2 11 +4.1 – 11 +4.0 a9 9.7 2.27 11 +4.0 – 11 +0.1 a10 9.9 2.00 (3الطريق نسبة لمواصفات جدول رقم ) تبليط(: فحص نسبة االسفلت والتدرج لنماذج 00جدول رقم) رقم المحطة )كم( النموذج نسبة االسفلت% %نسبة المستخدمةللسبة للوزن الكلي للتدرج نالنقص بنسبة العابر 111منخل رقم 41منخل رقم 8منخل رقم 2منخل رقم 11 – 11 +1.0 b1 4.65 0.0 0.10 2.70 11 +1.0– 11 +0.11 b2 4.55 0.2 4 2.0 11 +0.1 – 11 +0.0 b3 4.52 0.8 2.2 0.2 11 +0.0 – 11 +2.1 b4 4.45 0 2.0 4.2 11 +2.1 – 11 +2.0 b5 4.38 4 0.0 2.70 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 22 11 +2.0 – 11 +0.1 b6 4.3 2.0 0 0.1 0.8 11 +0.1 – 11 +0.0 b7 4.25 2.3 0.7 0.0 11 +0.0 – 11 +4.1 b8 4.34 0.7 2.7 0.24 11 +4.1 – 11 +4.0 b9 4.5 0.1 4 0.4 2.10 11 +4.0 – 11 +0.1 b10 4.6 0 2.3 0.0 ( 00و01،02حسب نتائج الجداول رقم) في الطريقتين التبليط تقييم حالة (: نتائج المقارنة في04جدول رقم) وعيوبه بالطريقة التقليدية التبليط حالة وعيوبه pci)ال)بطريقة حالة التبليط )كم(لمحطةا 1 / 11 +0 ( عيوب ابرزها هو 7يحتوي على) – متوسط الهبوط ،الشقوق التمساحية، التموجات، التخدد والشقوق الطولية وبعض السمك مواصفات فيلل مخالف واقل من الخلطة التصميمية في التدرج الثبات ، نسبة االسفلت واالنسياب 11 +0 – 11 +2 مساحية، الشقوق :عيوب( 3)فيه –متوسط التخددو شقوق طولية التموجات، الهبوط، وبعض السمك في مواصفاتلل مخالف في التصميمية الخلطة من واقل التدرج واالنسياب االسفلت نسبة، الثبات 11 +2 – 11 +0 هو ابرزها عيوب( 7)على يحتوي –ضعيف ، تفكك الهبوط ، التموجات التمساحية، الشقوق السطح والتخدد السمك ، حدلال في مواصفاتلل مخالف التصميمية الخلطة من واقل التدرج بعض و االنسيابو ، نسبة االسفلت في الثبات اكبروبدرجة 11 +0 – 11 +4 هو ابرزها عيوب( 3)على يحتوي –ضعيف ، التموجات التمساحية، الهبوط ، الشقوق الطولية والتخدد الشقوق السمك ،الحدل مواصفات فيلل مخالف التصميمية الخلطة من واقل التدرج بعضو االنسياب و نسبة االسفلت الثبات ، في وبدرجة اكبر 11 +4 – 11 +0 تمساحية شقوق ابرزها عيوب( 7)فيه –متوسط وتفكك السطح التخددالتموجات، الهبوط، ، بعضو السمك في مواصفاتمخالف لل في التصميمية الخلطة من واقل التدرج االنسيابو نسبة االسفلت الثبات ، 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 21 (astm d5623,2006)ال ملخص لمواصفات شدة العيوب المذكورة البحث وحسب مواصفات(:00)جدول رقم درجة شدة العيب ومواصفاته نوع العيب عالي متوسط واطئ طوليه شعرية خطوط التمساحية الشقوق القطع وترابط متوازية قليلة شبكه مكونة الشقوق التكسر منفصلة بأجزاء شقوق حفر توجد وقد بالزوايا الطولية الشقوق والعرضية من واقل مملوء غير شق ( ملم 01) عرضه يصل مملوء غير شق ملم( 70-01) من بعرض مملوء غير شق ملم (70اكثر من ) عالية ةبخشون تموجات نة متوسطةبخشو تموجات تموجات بخشونة قليلة التموجات ملم( 01)من اكبر عمقال (ملم01-20) لهبوطا عمق ملم( 20-00)لهبوطا عمق الهبوط ملم(20)من اكثر عمقال ملم ( 20 -00) االخدود عمق ملم(00-0)االخدود عمق التخدد تفكك السطح)التجوية( الرابطة تلف المادة بدء رشه وعند السطح وتفكك ضغطو البترول بزيت تخترقهال فيه النقود قطعة بشكل وخشونته السطح تفكك بزيت رشه وعند معتدل النقود قطعة وضغط البترول تخترقهفيه فأنها ونتهوخش السطح تفكك اقل بقطر حفرهو عالية اقل عمقبو مس (01) من هرشوعند مس( 00)من سيكون رخو بالزيت ويقدر تحديد يوجد ال ويقدر تحديد يوجد ال ال يوجد تحديد ويقدر تآكل الركام سم( 0 -0.0)من العمق الحفر سم (21 -01)من والقطر سم (0 -2.0)من عمقال سم( 40 -21)من قطرالو والقطر سم 0< العمق سم( 70 40) من 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 21 (: يبين نسب انواع العيوب في التبليط االسفلتي للطريق2الشكل رقم ) ( : العالقة بين نسبة االسفلت وقوة ثبات مارشال في نماذج اللباب االسفلتي1الشكل رقم ) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 21 المرجعية االسفلتية الخلطة ركام تدرج يوضح(: 0)رقم الشكل الطريق لتبليط االسفلتي اللباب نماذج في الحدل نسبة يوضح(: 2) رقم الشكل الطريق لتبليط االسفلتي اللباب نماذج في قوة ثبات مارشال يوضح(: 4) رقم الشكل 90 91 92 93 94 95 96 97 98 99 0 1 2 3 4 5 6 7 8 9 10 ل حد ال سبة ن % رقم نموذج اللباب االسفلتي %نسبة الحدل 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 21 الطريق لتبليط االسفلتي اللباب نماذج االنسياب في يوضح(: 4) رقم الشكل الطريق لتبليط االسفلتي اللباب نماذج في نسبة االسفلتا يوضح(: .) رقم الشكل : تبليطال عيوب صور الشدة متوسطة تمساحية شقوق( : 1)رقم رةالصو الشدة عالية تمساحية شقوق (: 2)رقم ةالصور 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 21 (: تموجات متوسطة الشدة 2رقم) ةالصور (: تموجات عالية الشدة 0رقم) ةالصور الشدة متوسط هبوط(: 4)رقم ةالصور الشدة عالي هبوط(: 4)رقم ةالصور الشدة متوسطة اخاديد (:8)رقم ةالصور الشدة عالية اخاديد (:.)رقم رةالصو 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 22 الشدة متوسط – الركام تآكل(: 21)رقم ةالصور الشدة عالية وعرضية طولية شقوق(: 9)رقم ةالصور متوسط الشدة الجو وتأثير السطح تآكل (:21)رقم ةالصور الشدة عالي الجو وتأثير السطح تآكل (:22)رقم ةالصور بالمواصفات الشدة عالية التمساحية الشقوق (:22رقم) صورة الشدة متوسطة حفرة(: 20) رقم رةصو 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 25 الطريق تبليط تربة لتسليح( geogrid)ال(:51رقم) صورة االسفلتي التبليط لتسليح الفوالذي شبكمال (:51رقم) صورة للعيوب الكلي الخصم قيمة تصحيح منحني(:51)رقم الشكل الحلة بمدينة الطهمازية شارع لموقع (:57)رقم جوية صورة الوارد بالمواصفات 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 20 ( : منحني قيمة الخصم لعيب الهبوط الوارد بالمواصفات91رقم) الشكل :مصادر الصور صور عيوب التبليط : تبليط شارع الطهمازيه -5 (. 52 -5الذي تم فيه البحث وهي من رقم ) ( من المصدر 51)صورة المشبك الفوالذي رقم -0 (03)وصورة المشبك البالستيكي رقم (4رقم) .(00)رقم المصدرمن ( من بلدية الحلة. 51الجوية رقم) ة الصور -0 ( من 1( و)1)والشكالن رقم (52الصور رقم ) -2 (astm d5623,2006)رقم المواصفات al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 268 effect of carbon black type on the mechanical behaviour of elastomeric material under dynamic loading abstract the mechanical behavior of filled elastomeric (rubber and rubber-like) materials is known to be incompressible, or nearly-incompressible, hyperelastic and time-dependent, or viscoelastic. this complex behavior of rubbery materials needs more understanding, and good knowledge is required for such behavior in order to achieve a good constitutive modeling for better design of a rubber component for a specific application. this work concentrated on studying the effect of carbon black type on the mechanical properties of rubbery material characterization. to do this, different tests were performed on filled rubber with three different kinds of carbon black n326, n375, and n660. all tests were performed at room temperature. the tests include rheometer tests, hardness tests, tensile tests, specific gravity tests, compression tests, relaxation test, and cyclic loading tests. tensile tests were done with different strain rate, relaxation tests done under different mean strain. tensile stress-stretch curves were generated from the test data at strain rate ranging from 10 to 500 mm/min and several transitions associated with strain-induced crystallization were observed in all materials. the filled rubber became stiffer when the strain rate increased from 10-200 mm/min, and became more compliant when the strain rate increased from 200 to 500 mm/min. hardness and specific gravity tests showed that rubber filled with carbon black n375 is harder and has specific density more than other two types of filled rubber. dr. mohsin noori hamzah university of technology muhsinnhamza@yahoo.com asia abdulsattar al-abadi al-qadisiya university asiarazak@yahoo.com al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 269 the mechanical compression set tests, which performed on rubber with three kinds of carbon black and found that compression set for rubber filled with carbon black n375 is more than the other two kinds of filled rubber. relaxation stress-time curves were generated from test data at varying mean strain ranging (50% to 200%) from the effective length of the specimen, at constant strain rate (200 mm/min). generally, it was observed that the stress reduces with time when the specimen hold at specific strain. this reduction is faster at strain between 50% and 100% than the strain between 150 to 200% till reaches steady state. series of cyclic tension tests were carried out at room temperature on a rubber compound under strain rate 200 mm/min. all these cyclic strain-controlled experiments showed that the filled rubber materials, used in the present work are time-dependence with hysteresis. it came out that hysteresis for rubber with carbon black n375 is more than the rubber with other two kinds of carbon black. تأثير نوعية اسود الكاربون على التصرف الميكانيكي للمواد االيالستومير تحت التحميل الحركي الخالصة : يعرف التصرف الميكانيكي للمواد االيالستومير (المطاط و المواد المشابهة للمطاط) المدعمة على انه غير قابل لالنظغاط او انه هذا التصرف المعقد للمواد المطاطية يتطلب فهم اكثر , ويتطلب قريب من ذلك , شديد المطيليه ويعتمد على الوقت او انه مرن لزج . الوصول الى نمذجة جيدة لتصميم افضل لمركبات المطاط عند استخدامها في مجال معين . هذا العمل يركز على معرفة جيدة من اجل لعمل هذا اختبارات مختلفة اجريت على المطاط دراسة تأثير نوع اسود الكاربون على خواص المواد التي توصف بانها مطاطية . ) . جميع االختبارات اجريت بدرجة حرارة الغرفة . االختبارات n660,n326,n375المدعم بثالث انواع مختلفة من اسود الكاربون ( ات تضمنت , اختبار الريوميتر , اختبار الصالبة , اختبار الشد , اختبار الثقل النوعي , اختبار االنضغاطية , اختبار االسترخاء , اختبار مختلفة , اختبارات االسترخاء اجريت عند متوسط انفعال مختلف . معدالت انفعالاختبارات الشد اجريت تحت . التحميل الدوري االستطالة حيث -ملم/دقيقة) تم توليد منحنيات االجهاد 500-10مختلفة تتراوح بين ( معدالت انفعالمن بيانات اختبارات الشد عند 10من يزداد معدل االنفعالم يصبح اصلب عندما المطاط المدع) . التبلورلوحظ ولجميع المواد عدة انتقاالت ترتبط مع (االنفعال يحث ملم/دقيقة . 500الى 200من معدل االنفعالنما يكون اكثر مطاوعة عند زيادة يملم/دقيقة ب 200ال ) اكثر صالبة وثقل نوعي من النوعين n375اظهرت اختبارات الصالبة والثقل النوعي ان المطاط المدعم باسود الكاربون ( رين من المطاط المدعم . االخرين االخ من اختبارات االنضغاطية الميكانيكية التي اجريت للمطاط بثالث انواع من اسود الكاربون اوجدت ان المطاط المدعم باسود له انضغاطية اعلى من النوعين االخرين من المطاط المدعم . ) n375الكاربون ( الدكتور محسن نوري حمزة الجامعة التكنولوجية اسيا عبد الستار العبادي جامعة القادسية al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 270 الوقت عند مستويات انفعال متغيرة تتراوح -انات التي تم الحصول عليها من اختبارات االسترخاء تم توليد منحنيات االجهاديمن الب ملم/دقيقة . بصورة عامة لوحظ ان االجهاد يتناقص مع 200 هوثابت معدل انفعال% من الطول الفعال للعينة وعند 200% الى 50بين % من االنفعال الذي 100% الى 50وهذا التناقص يكون اسرع عند انفعال يتراوح بين نفعال محدد . الزمن عند مسك العينة عند ا % حتى الوصول الى حالة االستقرار .200% الى 150يحدث عند انفعال بين كل التجارب .ملم/دقيقة) 200( معدل انفعاليت بدرجة حرارة الغرفة على المطاط تحت رسلسلة من اختبارات الشد الدوري اج النتيجة كانت ان الهسترة طاطية المدعمة هي تعتمد على الوقت مع الهسترة . مالتي تسيطر على االنفعال الدوري اظهرت ان المواد ال ) كانت اكثر من النوعين االخرين .n375للمطاط المدعم باسود الكاربون ( keywords: elastomer, large deformation, viscoelastic, carbon black, strain rate. 1. introduction rubber and rubber like materials are generally called elastomers. rubber has excellent properties that make it an excellent choice for tire industries, rubber has high mechanical strength and can be compounded to have excellent elasticity, good abrasion resistance, low relative cost, good dynamic mechanical properties, very good low temperature resistance [ciesielski 2000], down into the region of -57°c, inherent weather (uv light and ozone) resistance, and electrical insulation is very good. rubber also capable of adhering to textile fibers and metals, such as rayon, polyamide, polyester, glass, and steel cord. recently, many researches about elastomer materials revealed different properties, contrary for all real materials elastomer is incompressible or nearly incompressible material and exhibit a unique property that is a hyperelastic is extensible when subjected to a load with high deformation and could reach from 500% to 1000% and back to the original or almost original dimensions after unload depending on the time. in addition, carbon black is usually used as an additive for improving the rubber's strength, by inducing cross-links to form between the polymer chains in order to limit the chain's ability to move independently [makul & rattanadecho 2010]. the complex behavior of elastomer makes it impossible for its properties to be characterized by simple stress-strain relation which is useful in hard solids materials. the typical stress-strain curve shows nonlinear behaviour under large strain, so it is impossible to determine definite value to the young modulus unless obey to hooke`s law except in a region for small strain which show almost linear behaviour. elastomer materials properties need to be described by strain energy function. the principal point in modeling of elastomer material is to select the appropriate constitutive model which gives adequate parameters [hossa & marczak 2010]. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 271 the main objective of the present research is to study and investigate the effect of carbon black type on the mechanical behaviors of the three tread rubbery blends for farm tire which already used in babylon tires factory. three types of carbon black will be used; the testing results and the mechanical response will be the key factor for determining the best blend choice for the farm tire industry. 2. experimental 2.1 materials and sample preparation the materials and samples preparing processes were done in babylon tire factory laboratories. the gum material and additives were performed using the calendering machine, the mixing process continues till reaching a homogenous blend. the sulfur and accelerators are added at the end of the mixing process to avoid curing during calendaring processes. electrical piston was used to cure the blend, when the piston temperature reach (145ϲ°) the (70 gr) from the blend, table 1, pressed by mold for (45 min) to produce a thin sheet of rubber which can be used later to make the dumbbell specimen. table (1) shows the blend with carbon black n375, the two other recipes are the same but with carbon black n326 and n660. dumbbell specimens were obtained under astm d412 specifications for tensile test. same process but different molds were used to produce the specimen in order to use in hardness and density investigations. during this process the mold filled with the above blend and pressed under electrical piston for (15 min) with temperature up to (160 ϲ°) as show in figure 1. . 2.2 rheometer test. this test have been done by using monsanto rheometer (odr 2000e). the computerized printer reveals curves for the torque required to oscillate the rotor as a function of time. test results show in figures 2, 3 and 4 for the three blends. curve values printed out as abbreviated terms. these important terms can be explained as follows. ml (minimum torque): it is the lowest value of torque recorded when the compound heated under pressure in which the viscosity decreases and the torque fall. basically ml is a measure of the stiffness and viscosity of unvulcanized compound [future foundation 2003]. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 272 mh (maximum torque): as the curing starts, the torque increases proportionately. depending upon the type of compound, the slope of rising torque varies. after a while the torque typically attains maximum value and it plateaus out. it is called “plateau curve”. mh (max. torque) is the highest torque recorded in plateau curve. ts2 (induction time): after attaining minimum torque, during cure phase, as the torque rises, ts2 is scorch time for viscosity to raise 2 units above ml. is measure of initial slope of curing phase of rheograph i.e. this is measure of processing safety. scorch is premature vulcanization in which the stock becomes partly vulcanized before the product is in its final form and ready for vulcanization. scorching is the result of both the temperatures reached during processing and the amount of time the compound is exposed to elevated temperatures. this period before vulcanization starts is generally referred to as “scorch time”. since scorching ruins the stock, it is important that vulcanization does not start until processing is complete. t90 (optimum cure time): it is the time at which 90% of cure has taken place. table 2 summaries the values of these terms for the three blends used in the current analysis. 2.3 hardness test as hardness is probably the most widely used cured property of rubber so the scientist efforts were considerably concentrated on making the hardness test more easily and practical and regard this test is somewhat subjective. in present work wallace units i.r.h.d instrument was used for hardness test (shore a). table 3 shows the results obtained from hardness test for the same blend with different kinds of carbon black used in the current work. 2.4 tensile tests these tests have been carried out by using the instrument showing in figure 5 type monsanto tensometor 10. to starting the test the instrument must be fed by input data, thickness, width and the strain rate. the experiment has been repeated with different strain rates for all three blends starting from 10 mm/min then increased to 25, 50,100, 200 and 500 mm/min. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 273 2.5 compression set tests these test methods cover the testing of rubber intended for use in applications in which the rubber will be subjected to compressive stresses in air or liquid media. they are applicable particularly to the rubber used in machinery mountings, vibration dampers, and seals. the specimen used in this test showing in figure 1b which is a disk of rubber have diameter (29±1) mm and thickness (12±1) mm. the device used in the test is consisting of a force application spring and two parallel compression plates assembled by means of a frame or threaded bolt in such a manner that the device shall be portable and self-contained after the force has been applied and that the parallelism of the plates shall be maintained. the force may be applied in accordance calibrated spring force application. the required force shall be applied by a screw mechanism for compressing a calibrated spring the proper amount. the spring should be of properly heat-treated spring steel with ends ground and perpendicular to the longitudinal axis of the spring. the spring should be calibrated at iron box with temperature 23 ± 5°c. calculation process needed to find compression set as a percentage of the original thickness as follows [astm international committee 2008]: 𝐶𝐴 = ((𝑡𝑜 − 𝑡𝑖)/𝑡𝑜 ) ∗ 100 (1) where ca is the compression set as a percentage of the original thickness, 𝑡𝑜 is the original thickness, and 𝑡𝑖 is the final thickness. table 4 shows the compression set tests of the three blends, from this table it can be recognized that the blend with carbon black n375 have higher compression set than that in blends with carbon black n326 which is in turn more than n660 compression set. 2.6 specific gravity test this property is fully defined by the composition of the material. the specific gravity is the mass per unit volume and is measured by weighing the sample in air and in water according to the following formula [rubber precision parts 2011]: 𝐺𝑠 = 𝑤𝑎𝑖𝑟 (𝑤𝑎𝑖𝑟−𝑤𝑤𝑎𝑡𝑒𝑟) (2) al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 274 where 𝐺𝑠 is the specific gravity, 𝑤𝑎𝑖𝑟 is the weight in air, and 𝑤𝑤𝑎𝑡𝑒𝑟 is the weight in water. the test done by using monsanto-densitron instrument, the sample showed in figure 1c. the instrument consists of a closed room as a container. the inside of this room has a drawer which is divided for many places and slide horizontally to put and remove the samples. below this slide there is a basin filled by water. the instrument has clamps to carry the sample from the slide to the basin water and return it back to its position in slide automatically. the operation of the instrument is totally programmed and the operation start immediately after putting the sample on the slide in the specific place and close the room’s door. table 5 shows the results for three blends. 2.7 stress relaxation test rubber is classified as viscoelastic materials, viscoelastic materials appear both elastic solid and a viscous fluid response when deformed. the main important method to study and compare the viscoelastic compounds properties is stress relaxation experiment method [karrabi & mohammadiangezaz 2011]. stress relaxation can be defined as continued decreasing in stress needed to maintain a given deformation or loss of stiffness with time. this test has been carried out by using monsanto tensometor 10 instrument, showed in figure 5, which the same instrument used in tensile test before. dumbbell specimen used in the relaxation test is shown in figure 1a. the procedure started by holding both ends of the sample via clamps of the instrument. as in tensile test the effective length of the sample is the distance between the two holders which fixed at length (25 mm), then fed the instrument by input data which like, thickness, width of the sample and strain rate. strain rate was fixed at 200 mm/min for all experiment duration. after completing all those steps the tensile stress was applied and continued till the deformation reached 200% and then stopped. the decreasing in stress was recorded by using video camera. the period of recording the data were continued for 5 minutes and the values taken were used for drawing the relationship between time and stress. same steps were repeated for each blend used in this work. all the above steps and procedures were repeated for deformations 150%, 100% and 50%. 2.8 cyclic loading tests in order to validate the cyclic tension test, uniaxial stretching experiments are performed at room temperature. these uniaxial cyclic tests are conducted on dumbbell specimens shown in figure 1 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 275 under controlled strain, for different strain rate, three loading cycles at constant strain level were carried out for all kind of blends. machine test was used for this process, show in figure 6, which is testometric ax-m500-25kn. each test can be managed by using a computer connected to the machine which fully control the test using wintest™ analysis universal testing software. this is a multifunctional and fully customizable software package that supports all industry standards including iso, astm and bs en specifications. test specifications supported include tensile, compression, flexural, peel, tear, burst, adhesion, shear, cyclic and hardness. additional flexibility is provided by user-defined multistage step testing for highly specialized testing requirements. data input to the program to perform the test are specimen length, width, thickness, strain level and strain rate. results obtained from the test were force and elongation. the engineering stress was calculated by dividing the force to original area. depending on strain value, the stretch was calculated as follows: 𝜆 = 1 + δ𝑙 𝑙𝑜 (3) where 𝜆 is the stretch, δ𝑙 is the strain and 𝑙𝑜 is the original length. 3. results and discussion the recorded values were used later to draw the stress-stretch curve. the shapes of the curves are shown in figure 7 through 9. from the above curve it can be notes that the tensile strength for three blends increased with strain rate increasing, but when the strain rate reached high value about 500mm/min the tensile strength tend to decline to lower value. curves in figures 10 through 12 show the relationship between stress and time for different blends with different deformations which represent the relaxation phenomena. three cyclic curves for three blends were plotted at strain rate 200mm/min as show in figure 13 through 15. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 276 4. conclusions the objective of this research is to determine the deformation and viscoelastic behavior for filled elastomeric material under mechanical and cyclic tests and study the effect of the variation of strain rate. another purpose is to study the effect of the different three types of filled carbon black (n326, n375 and n660) on the mechanical and dynamic behavior of the rubber. hardness test for three blends gave results, showing that the hardness for the blend with carbon black n375 is more than that in blend with carbon black n326 which in turn more than hardness in blends with carbon black n660. the reason for that is the surface area for carbon black n357 is larger than the surface area for carbon black n326 which in turn has a surface area larger than that in carbon black n660. the higher amount of surface area gives a high degree of cross linked. the degree of cross-linking has a great effect on the hardness of the elastomer. also, it has the same effect on the compression set and the specific gravity material tension was performed on three blends. the material tension tests were done in order to characterize material stiffness and strength according to strain rate. all tests were done in room temperature and for deformation 200%. in general, and for all strain rates blend with carbon black n375 is stiffer than the others. also blend with carbon black n326 is stiffer than blend with carbon black n660 till 100% strain, contrary for strain 100 to 200% blend with carbon black n660 is stiffer than the blend with carbon black n326. all three blends became stiffer when the strain rate increased. for blend with carbon black n375 the stiffness increase from 10 to 100 mm/min, and it became more compliant when the strain rate increased from 100 to 500 mm/min. for blends with carbon black n326 and n660 stiffness increase from 10 to 200 mm/min and it becomes more compliant when the strain rate increased from 200 to 500 mm/min. it was proposed that the increase in stiffness at high rates of loading resulted from the lack of relaxation time in the chain molecules [imaoka 2008] and due to strain –induce crystallization and the time is insufficient under high strain rate [ali et.al 2010]. stress relaxation test was carried out for three blends at room temperature and strain rate (200 mm/min) with different deformations (50, 100, 150 and 200% strain). relaxation at 200% strain, filled compounds containing finer carbon black, i.e., blend with carbon black n375 showed higher initial relaxation stress which drops more rapidly as time passes, which subsequently stabilized. this attributed to the loss of viscous motions which are related to carbon black interactions trapped in the cross-links and cannot be broken down [hussain 2005]. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 277 filler aggregates in a polymer matrix have to form a filler network. during dynamic strain, if the filler network cannot be broken down, the elastic modulus would increase substantially due to the rubber trapped in the network [meng-jiao 1998]. it was found that the amount of trapped rubber increases with filler loading and low hysteresis. when the network of the filler breakdown and reformation happened the additional energy dissipation occurs and then higher hysteresis would be expected during cyclic strain. that exactly occurred for blend with carbon black n375 because it had higher filler network. references [1] ciesielski a., an introduction to rubber technology, rapra technology limited, shropshire sy4 4nr, united kingdom, 2000. [2] makul n., and rattanadecho ph.,” microwave pre-curing of natural rubber-compounding using a rectangular wave guide”, international communications in heat and mass transfer 37, pp. 914– 923, 2010. [3] hossa l., and marczak r. j.,” a new constitutive model for rubber-like materials”, eduardo dvorkin, marcela goldschmit, mario storti (eds.), 2010. [4] future foundation,”oscillating disc rheometer”, mercury house 16 community centre, wazirpur industrial area delhi 110052, 2003. [5] astm international committee,”standard test methods for rubber property—compression set”, 100 barr harbor drive, po box c700, west conshohocken, pa 19428-2959, united states, 2008. [6] rubber precision parts,”rubber technology”, zoreg, hungary,2011. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 278 [7] karrabi m. and mohammadian-gezaz s.,” the effects of carbon black-based interactions on the linear and non-linear viscoelasticity of uncured and cured sbr compounds”, iranian polymer journal 20 (1), pp. 15-27, 2011. [8] imaoka sh.,” mechanical solutions from ansys have convenient tools for calculating deformation of materials in which stiffness changes as a function of loading, time and temperature”, ansys advantage volume ii, issue 4, pp. 46-49, 2008. [9] ali a., hosseini m. and sahari b.b.,”a review of constitutive models for rubber-like materials”, american journal of engineering and applied sciences, 2010. [10] hussain s. a.,” effect of carbon black fillers on high strain rate properties of natural rubber”, university of akron, 2005. [11] meng-jiao w.,” the role of filler networking in dynamic properties of filled rubber”, meeting of the rubber division, american chemical society, 1998. table 1: the recipe of the blend used in tread of farm tire quantity in gm phr* sbr 1502 85.5 100 sbr 1712 142.5 br cis 56.4 zno 7.2 2.53 stearic acid 4.2 1.47 6ppd 5.7 2 tmq 3 1.05 wax 5.7 2 paraffin oil 56.7 19.93 sulfur 4.5 1.58 mbs 3 1.05 carbon black n375 183.6 64.55 reclaimed rubber 42 14.76 * parts per hundred rubber al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 279 table 2: summarize rheometer tests results for the three blends ml n-m mh n-m ts2 m.m t90 m.m blend with n375 1.169 4.210 0.88 2.47 blend with n326 0.962 3.488 0.95 2.84 blend with n660 0.766 3.237 0.99 2.73 table 3: i.r.h.d hardness test results blend with carbon black n375 n326 n660 hardness 57 57 51 table 4: compression set for three blends blend with different carbon black original thickness (𝑡𝑜) mm final thickness (𝑡𝑖) mm compression set (ca) n375 11.89 11.14 6.30 n326 11.86 11.15 5.986 n660 11.85 11.23 5.23 table 5: specific gravity test results blend type n375 n326 n660 specific gravity 1.131 1.122 1.112 (a) (b) (c) figure 1: (a) dumbbell specimens, (b) compression set specimen, (c) hardness and density specimens al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 280 figure 2: rheograph for blend with n375 figure 3: rheograph for blend with n326 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 281 figure 4: rheograph for blend with n660 figure 5: tensile test instrument, monsanto tensometor 10 al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 282 figure 6: cyclic tension test machine testometric ax-m500. figure 7: stress-strain relationship for blend with n375 at different strain rate 0 1 2 3 4 5 1 1.5 2 2.5 3 loading rate 1 cm/min loading rate 2.5 cm/min loading rate 5 cm/min loading rate 10 cm/min loading rate 20 cm/min loading rate 50 cm/min mpa al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 283 figure 8: stress-strain relationship for blend with n326 at different strain rate figure 9: stress-strain relationship for blend with n660 at different strain rate figure 10: stress relaxation for blend with carbon black n375 at different deformation 0 1 2 3 4 5 1 1.5 2 2.5 3 loading rate 1cm/min loading rate 2.5 cm/min loading rate 5 cm/min loading rate 10 cm/min loading rate 20 cm/min loading rate 50 cm/min mpa 0 1 2 3 4 5 1 1.5 2 2.5 3 loading rate 1 cm/min loading rate 2.5 cm/min loading rate 5 cm/min loading rate 10 cm/min loading rate 20 cm/min loading rate 50 cm/min mpa 0 2 4 6 8 0 100 200 300 at 50 % at 100% at 150% at 200% σ time (s) mpa al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 284 figure 11: stress relaxation for blend with carbon black n326 at different deformation figure 12: stress relaxation for blend with carbon black n660 at different deformation 0 1 2 3 4 0 100 200 300 at 50% at 100% at 150% at 200% σ time (s) mpa 0 1 2 3 4 5 6 0 100 200 300 at 50% at 100% at 150% at 200% σ time(s) mpa al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 285 figure 13: three cycles for blend with carbon black n326 at strain rate 200 mm/min. figure 14: three cycles for blend with carbon black n375 at strain rate 200 mm/min. 0 1 2 3 4 5 1 1.5 2 2.5 3 cycle no.1 cycle no.2 cycle no.3 σ mpa stretch, λ 0 1 2 3 4 5 1 1.5 2 2.5 3 cycle no.1 cycle no.2 cycle no.3 σ mpa stretch, λ al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 286 figure 15: three cycles for blend with carbon black n660 at strain rate 200 mm/min. 0 1 2 3 4 5 1 1.5 2 2.5 3 cycle no.1 cycle no.2 cycle no.3 σ mpa stretch, λ al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 186 stochastic models of some properties of waste water in the maamera sewage treatment plant dr. nabaa shakir hadi nabaalshimmri@yahoo.com college of engineering, university of babylon, babylon, iraq received 30 november 2014 accepted 3 february 2015 abstract the records of influents concentration for both bod5 and tss of maamera sewage treatment plant which were chosen of this study are very important parameters, they play an important part in the planing and management of the national water resources. most of these records have periods of missing data of the influent bod5 and tss. in this study a model for generating missing monthly concentrations influent bod5 and tss. data are introduced. initially univariate models using the box-jenkins approach were fitted to the logarithmically transformed series. both transformed series were found to be generated by a random process using sampling theory were considered to be white noise. ordinary regression analysis was performed. no significant correlation between influent bod5 and tss concentration were found. key-words: maamera sewage treatment plant, statistical analysis, stochastic models. فضالت المياه في محطة معالجة مياه المجاري في المعيميرةنماذج عشوائية لبعض خصائص الخالصة رنوعلمم يثرالممفلييثألافاممل يراتغلممخثمثييألاممفيتممفي مماياممحثيثراسمم يلخثامم ييثره ممفضاليرالممفليثرمحمم ميثرلثهامم يراس مم يا فر مم يثرا الممخ لثخ يثراموثخليثرافضلم ي,يسل يأنهفيتا بيلوخثيافافي ماواايثرا ابيثرسلوييرألوكا لنيوثراوثليثر اا يثر فرق ا ظمفيامحلييثرته مل يوثد ثرالفنمفميثرهمهخل يياإلهمف تمفيلخثام ياوللم يي اا امبيثرسلموييرألوكام لنيوثراموثليثر ماا يثر فرقم ر تخثميرالفنفميامقمول يي لهفيثرالفنفم ل ضمفيياوللم يثسمفلييثراتغلمخيافامتهلثفي خلقم ياموكيي لنكلنمزي ثرا امبيثرسلموييرألوكام لنيوثراموثليثر ماا يثر فرقم يرتخكلزثرامقول ي ثرتسممول ميراا امم يثرزانلمم ي ممايكمم يثرتسممول ميراا امم يلو مملياتغلممخيعهمموثضاياعاممتهلثفينامموحدينظممخييل اممخيعنمم ي يوافاممتهلثفي ي ثر اا يثر فرق النيعلفيو وليثختاف يالنيثرتخثكلزيثرلثها يراا ابيثرسلوييرألوكا لنيوثراوثليتيتسال يثالنسلثخ 1. introduction engineers who take up the task of analyzing flows, bod5, etc. into stream for the purposes of design and planning are often confronted with the problem of working with records having a sequences of missing data. in this study, the readings of influent of bod5 and influent of total suspended solid of the wastewater from maamera sewage treatment plant were considered for the analysis in time series. mailto:nabaalshimmri@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 187 the infilling of missing values in hydrological data involves the use of statistical procedures of data generation one of such methods is the use of univariate linear stochastic models[al-samawi,1986]. box and jenkins (univariate models) techniques which were used to determine the appropriate model. these represent the structure of the time series then tests of these values by the chi-square goodness of fit test and k.s test were performed to check the normality of the data[hussain,2000]. many wastewater treatment plants were built within hilla city. al-maamera sewage treatment plant is one of these plants and has begun to operate in 1982. the plant works with an activated sludge system which biologically treats compounds of carbon and nitrogen in raw wastewaters. maamera sewage treatment plant serve 50000 populations and the treatment facility is a conventional activated sludge system with an average wastewater inflow of 12000 m 3 /day. the sewerage system is designed to accommodate the industrial wastewater, as well as domestic effluent. the treated wastewater in the plant is then being discharged to shatt al-hilla river. a full outline of the plant units is shown in fig. 1. the objectives of the study is to investigate and analyzed the applicability of such stochastic models to the influent of bod5 and tss. in the wastewater of the city of hilla during the years, 2008 to 2013. 2. methods in the present study, certain data have been collected yearly by the mayoralty of hilla from the influent in maamera sewage treatment plant. major water quality parameters were selected for this study; biochemical oxygen demand (bod5), total suspended solids (tss) over a period of six consecutive years. 3. theory the mean of every monthly readings of influent bod5 and tss. the parameters that the study depends on the first must be known so that of the time series and its components could be construct. 3.1 definitions time series model a time series is defined as a set of observations that measure the variation in time of some aspect of a phenomenon, such as the rate of the dissolved oxygen in the stream and the total suspended solids, or the sediment load in a channel [kottegoda, 1980]. 3.2 components of time series: 3.2.1 trend: trend is a steady and regular movement in a time series through which the values are on average either increasing or decreasing. 3.2.2 periodicity this represents a regular or oscillatory form of variations such as seasonal effect which clearly evident in closely spaced data. in general, the periodic component in a time series can be represented through a system of sin functions after the trend component, if it exists, has been estimated and removed [kottegoda, 1980]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 188 3.3 time series model if a high degree of dependency between sequential observations exists, then forecasting technique which express this dependency and which will generally produce superior results can be applied. these techniques which are presented by box and jenkins are called box – jenkins model. these techniques are used to identify the appropriate model, other variables and estimate the parameters of the stochastic models. in general; the model are formulated so that the current value of a variable is the weighted sum of past values and a random values which represents the unknown. 3.4 parameters of the model: 3.4.1 autocorrelation function(acf) for series,which are not random, there will be dependency between sequential observations. a useful tool to measure this effect is the autocorrelation function which may be defined as: 𝜌(𝑘) = 𝐸(𝑋𝑡 − 𝑈𝑥 )(𝑋𝑡+𝑘 − 𝑈𝑥 ) √𝐸(𝑋𝑡 − 𝑈𝑥 ) 2. 𝐸(𝑋𝑡+𝑘 − 𝑈𝑥 ) 2 (1) the autocorrelation function has the following properties: 𝜌(0) = 1 |𝜌(𝑘)| ≤ 1 𝑓𝑜𝑟 𝑎𝑙𝑙 𝑘 ≠ 0 𝐴𝑛𝑑 𝜌(𝑘) = 𝜌(−𝑘) for an observed time series 𝑋𝑡 of length n, the autocorrelation function of lag k can be estimated from 𝑟(𝑘) = ∑ (𝑋𝑡 − �̅�)(𝑋𝑡+𝑘 − �̅�) 𝑁−𝐾 𝑡=1 ∑ (𝑋𝑡 − 𝑋) 2𝑁 𝑡=1 (2) where: �̅� = 1 𝑁 ∑ 𝑋𝑡 (3) 𝑁 𝑡=1 3.4.2 partial autocorrelation function(pacf) the partial autocorrelation function at lag k is the correlation between xt and xt+k with the effects of the intervening observations(xt+1 ,xt+2 ,…….,xt+k-1) removed. [montgomery and johnson, 1976]. notationally, we shall refer to the k th partial autocorrelation coefficient as ∅𝑘,𝑘 the set of parameter ∅1,1, ∅2,2, ∅3,3, which are the last coefficients of the autoregressive models of order 1,2,3,… respectively represent the partial autocorrelation coefficient. a plot of ∅𝑘,𝑘 versus the lag k is called the sample partial autocorrelation function. in general, the partial autocorrelation ∅𝑃,𝑃 is the autocorrelation remaining in the series after fitting a model of order (p-1) and removing the liner dependence. the partial autocorrelation function(pacf) is an important tool in determining the order of the model if the serial correlation function suggests that the process could be approximated by a linear autoregressive model. as a general rule,we would assume a partial autocorrelation coefficient to be zero if the absolute value of its estimate is less than twice its standard error [kottegoda,1980]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 189 3.4.3 autoregressive processes(ar) the autoregressive processes means that the current observations xt is "regressed" on previous realizations xt-1,xt-2,…xt-p of the same time series[montgomery and johnson,1976]. the autoregressive model ar(p) takes the form. 𝑋𝑡 = ∅𝑃,1𝑋𝑡−1 + ∅𝑃,2𝑋𝑡−2 + ⋯ ∅𝑃,𝑃 𝑋𝑡−𝑃 + 𝑎𝑡 = ∑ ∅𝑃,1𝑋𝑡−1 + ∅𝑡 𝑃 𝑖=1 (4) where ∅𝑃,𝑖 𝑖 = 1,2,3, … , 𝑃 are the autoregressive parameters or weights and (at) is a white noise process or residuals, the model in eauation(4) is called an autoregressive process of order p, abbreviated ar(p). also, the model called a linear autoregressive model, in which the current value of a variable is equated to the weighted sum of a (p) number of past values. a variant (at) that is completely random, the word linear merely signifies that the current value is dependent additively upon the past values and not for example, on their squares or square roots [kottegode, 1980]. 4. results and discussion 4.1 the data the data used in this study are the average of each months for the six-year (2008 – 2013) period for both of influent of bod5 and tss into maamera sewage treatment plant. 4.2 time plot 2.1 both of the two figs (2&3) show that the behavior of the original time series for both influents bod5 and tss these fig show: a. the maximum value for influent bod5 was (214mg/l) in april 2012. while the minimum value for influent bod5 was (75mg/l) in novmaber 2013. b. the maximum value for influent tss was (301mg/l) in march 2009. and the minimum value for influent tss was (93mg/l) in march 2010. 2.2 from figs (4&5) it was noted that, the standard deviation for every year was directly perpotional to the mean in that year. it is noted in the beginning, the standard deviation was low and so was the mean while during the last year the standard deviation became higher with the mean. all these indicated that a logarithmic transformation of the data was needed to stabilize the variance and to make multiplicative effects additive. 4.3 transformation after adjusting the outlier observation the logarithms for the original time – serieses were taken and are plotted as shown in the figs (6&7) for both influents bod5 and tss these fig show: a. the standard deviation become constant with the increase of the mean. b. the variation patterns during every year for these series are similar to the variation patterns of the original series. the values for both influent bod5 and influent tss are shown in table1. 4.4 autocorrelation from figs (8&9) for influent bod5 and influent tss respectively, the autocorrelation function of the series have no trend and seasonality. since the autocorrelation function have the ability of all al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 190 lags are not significant and also,the function have no seasonal cycles[hipel et al.,1977b], hence the time series has no deterministic for stochastic component from figs (10&11) for influent bod5 and influent tss. it can be that, show the partial autocorrelation functions for two series with confidence limits of (95%). from these four figs, it can be seen that all autocorrelation coefficient will be within the confidence limits (95%). hence , it can be said that the two series were (serially independent). 4.5 test of normality the test is carried out by two ways: 4.5.1 chi-square test the chi –squared statistic depends on specifying the number of histogram classes into which the data will be grouped, and there is no rule that gives the correct number to use [vose, 2010]. the chi –squared test statistic is computed from the relationship: x2 = ∑ (oi−ei) 2k i=1 ei (5) where 𝑂𝑖 is the observed and 𝐸𝑖 is the expected number of observation in the ith class interval(based on the probability distribution being tested). the expected numbers are calculated by multiplying the expected relative frequency by the total number of observation[barkotulla et al.,2009].the chi square test parameters are shown in tables (2) and(3) for influent bod5 and tss respectively. from table (2) it is seen that, the values of 𝑥2 = 7.8508 for influent bod5 and all the expected frequencies were be larger than or equal to 5[crof,1979]. the chi-square value is found to be (0.25). this value is within the acceptable region for the normally distributed and that it is white noise series as shown in fig(12). for influent of tss, the values of 𝑥2 = 3.5747 and all expected frequencies were greater than(5) as shown in table (3). the chi-square value was (0.75). this value is within the acceptable region for the normally distributed and that it is white noise series as shown in fig(13). 4.5.2 kolmogorov-smirnov test kolmogorov-smirnov(k-s)goodness of fit test is based on a statistic that measures the deviation of the observed cumulative histogram from the hypothesized cumulative distribution function [soong, 2004].by using this test, the significant level for influent bod5 was (0.441), and for influent tss.was (0.642) as show in table (4). from all this it can be concluded that the series are white noise and have normal distribution as was obtained from(chi-square test). 4.6 regression analysis the study of regression had done on the three relationships the first relation was between influent of bod5 and tss. the data of this relation can be seen from table (5) and the plot of this relation is shown in fig(14). second trial was carried out between the influent bod5 and the transformed values of tss, as it seen in table(6) and fig(15). third trial had performed out between the transformed function of influent bod5 and the transformed values of tss, as it seen in table(7) and fig(16). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 191 from these three relations, it can be seen that there is no physical relation exist between influent bod5 and tss. the values of r 2 for this test were (0.019),( 0.028), and (0.017),respectively. these values were too low to say that the model was adequate for prediction. 4.7 one-step-ahead-forecast the forecasting of the sample for influent bod5 and tss, during the period of recording the data (2008 to 2013) is depend upon the sampling theory. from the theory of sampling is the estimate of both bod5 and tss. can be found by the following expression: �̅� ± 2𝑆𝑒 (6) where: �̅�: is the mean for the influent bod5 and tss. 𝑆𝑒: is the standard error for the mean influent of bod5 and tss. then for influent bod5 the forecasting value is (168.19 , 241.71 ) mg/l while for the influent tss. it is (247.78 , 353.32)mg/l. 5. conclusions the following conclusions are drawn from this study: 1. the need for the logarithmic transformation of both influent bod5 and tss concentrations data indicates that the two parameters which generate data are non linear in nature. 2. the deterministic component of data of both influent bod5 and tss. 3. the time series of both transformed influent bod5 and tss is white noise series without residual series. 4. the seasonal effect is not present, so if the time series tales values more than 72 value may be the seasonal effect appear. 5. box-jenkins models are not applicable here because the randomness of the data. 6. the forecasting values are derive from the sampling method are tabulated these forecasting values( no each case an interval estimate is given) should be up dated to monitor the values of �̅�and 𝑆𝑒 for each variable(bod5 and tss). 7. relationship between influent bod5 and tss concentration: an attempt was made to relate the influent tss concentration, which is usually easy to measure, with the influent bod5 which is takes lengther time to determine. the range of possible mathematical relationships covered in this analysis are as follow: (i)the simple linear form, 𝐵𝑂𝐷5 = 𝑎 + 𝑏 𝑇𝑆𝑆 (7) (ii)the inverse form, 𝐵𝑂𝐷5 = �́� + �́�𝑙𝑛 𝑇𝑆𝑆 (8) (iii)the semi inverse form, 𝑙𝑛𝐵𝑂𝐷5 = �́́� + 𝑏 ́́ 𝑙𝑛 𝑇𝑆𝑆 (9) figs (14),(15) and (16) show the following al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 192 no visual relationship between influent bod5 and tss, exists according to the mathematical formulations as given in equations(7),(8) and(9). this finding is supported by the results of the statistical regressions which are tabulated in table(5),(6) and (7). in all mathematical formulations, the slope coefficients b, �́�, 𝑎𝑛𝑑 𝑏 ́́ were found to be insignificant, thus supporting the findings that no physical relations between influent bod5 and influent tss. hence, the best model which represent the variability of the influent bod5 is given by the lognormal distribution. similarly, influent tss. a concentration may be modeled in the same manner. references [1] al-samawi, a. a. (1986). "the generation of missing river flow data", arab gul,j.of scientific research. vol.4, no.2. pp.761-774. [2] barkotulla m.a.b., rahman m.s., and rahman m.m.,(2009). "characterization and frequency analysis of consecutive days maximum rainfall at boalia, rajshahi and bangladesh", india, journal of development and agricultural economics vol. 1(5). pp.121-126. [3] chatfield, d. (1979). "statistics for technolgy", champaman and hall,2 nd edition. [4] croft. d. (1979)."applied statistics for management studies", macdonald and evans, 2 nd edition. [5] hipel, k, w., mcleod, a. i. and lennox, w. c. (1977). "advances in box-jenkins modeling 2. applications", water resources research, vol.13,no.3.pp.577-586. [6] hussain, s. m., (2000). "time series analysis for hydrochemical pollutants: applications of box-jenkins models to euphrates river at kufa". m.sc. thesis, university of babylon. [7] kottegode, n. t., (1980). "stochastic water resources technology", the macmillan press ltd. [8] maidment, d. r. and parzen, e. (1984). "cascade model of monthly municipal water use", water resources research, vol. 20. no. 1, pp. 15-23. [9] soong t.t., (2004). "fundamentals of probability and statistics for engineers", john wiley & sons ltd, state university of new york at buffalo, new york, usa. [10]vose, david.,(2010). "fitting distributions to data and why you are probably doing it wrong", 15 feb 2010, www.vosesoftware.com. http://www.vosesoftware.com/ al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 193 table (1): descriptives parameter mean standard deviation standard error bod5 4.9703 0.2552 0.03095 tss 5.2185 0.2194 0.02661 tables (2): chi-square test for the influent bod5 lower limit upper limit observed frequency expected frequency chi-square at or below 4.55 6 5 0.1403 4.55 4.67 6 7 0.1428 4.67 4.79 4 8 2.0075 4.79 4.91 8 10 0.4036 4.91 5.03 13 10 0.8410 5.03 5.15 10 10 0.0022 5.15 5.21 9 6 1.3787 5.21 5.27 4 7 1.2857 above 5.27 8 5 1.6490 chi-square=7.8508 with 6 dif, sig.level=0.25 tables (3): chi-square test for the influent tss lower limit upper limit observed frequency expected frequency chi-square at or below 4.92 4 5 0.2568 4.92 5.05 9 7 0.4787 5.05 5.13 8 6 0.5565 5.13 5.21 9 13 1.3097 5.21 5.29 14 13 0.0769 5.29 5.37 10 8 0.4199 5.37 5.45 5 6 0.2150 5.45 5.58 5 5 0.0044 above 5.58 4 5 0.2568 chi-square= 3.5747 with 6 dif, sig.level=0.75 table (4): the values of kolmogorov-smirnov test for all the influents and with confidence level equal 95% parameters estimated kolmogorov statistics dplvs estimated kolmogorov statistics dplvs estimated overall statistics dn approximate significance level bod5 0.105 0.085 0.105 0.441 tss 0.090 0.087 0.090 0.642 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 194 table (5): regression analysis-linear model y=a+bx dependent variable:bod5 independent variable:tss parameter estimate standard error t-value probability level intercept slope 125.613 0.121 20.906 0.108 6.008 1.119 0.000 0.267 analysis & variance sourc e sum of square d.f. mean square f-ratio probability mode l error 1567.889 82599.097 1 66 1567.889 1251.501 1.253 0.267 total(correlation)= 84166.985 d.f.= 67 correlation coeffication=0.136 standard error estimate=35.377 r-squared=0.019 table (6): regression analysis-linear model y=a`+b`lnx dependent variable:bod5 independent variable: lntss parameter estimate standard error t-value probability level intercept slope 8.541 26.822 102.398 19.605 0.083 1.368 0.934 0.176 analysis & variance source sum of square d.f. mean square f-ratio probability model error 2321.257 81845.728 1 66 2321.257 1240.087 1.872 0.176 total(correlation)= 84166.985 d.f.= 67 correlation coeffication=0.166 standard error estimate=35.215 r-squared=0.028 table (7): regression analysis-linear model lny=a``+b``lnx dependent variable:lnbod5 independent variable: lntss parameter estimate standard error t-value probability level intercept slope 4.169 0.154 0.741 0.142 5.625 1.082 0.000 0.283 analysis & variance source sum of square d.f. mean square f-ratio probability model error 0.076 4.288 1 66 0.076 0.065 1.171 0.283 total(correlation)= 4.364 d.f.= 67 correlation coeffication=0.132 standard error estimate=0.25488 r-squared=0.017 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 195 figure (1): image map of maamera sewage treatment plant, hilla (al-maamera project office, 2012). figure (2): time series of influent bod5 figure (3): time series of influent tss of al-maamera s.t.p. of al-maamera s.t.p. 60 80 100 120 140 160 180 200 220 240 0 10 20 30 40 50 60 70 80 in fl u e n t o f b o d 5 ( m g /l ) time(unit time=monthly period). 80 110 140 170 200 230 260 290 320 0 10 20 30 40 50 60 70 80 in fl u e n t o f t s s ( m g /l ) time(unit time=monthly period). (1) sediment tanks (2) reaeration tanks (3) primary stage (4) office storages (5) dilution tanks (6) new dilution tanks (7) new reaeration tanks (8) final stage (9) storage tanks (10) pump sediment stage (11) new sediment tanks (12) compact unit station 12 2 4 3 7 11 6 5 8 9 10 1 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 196 figure (4): standard devation of influent figure (5): standard devation of influent of bod5 vs. mean. of tss vs. mean. figure (6): transformed of infl. bod5 series figure (7): transformed of infl. tss series figure (8): autocorrelations for influent figure (9): autocorrelations for influent bod5 series tss series r² = 0.3375 y = 0.3562x + 1.649 0 20 40 60 80 100 120 0 50 100 150 200 250 s ta n d a rd d e v a ti o n ( m g /l ) mean (mg/l) y = 0.7878x 50.66 r² = 0.477 0 50 100 150 200 250 0 50 100 150 200 250 300 350 s ta n d a rd d e v a ti o n ( m g /l ) mean (mg/l) 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 0 10 20 30 40 50 60 70 80 in fl u e n t o f b o d 5 ( m g /l ) time(unit time=monthly period). 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 0 10 20 30 40 50 60 70 80 in fl u e n t o f t s s ( m g /l ) time (unit time=monthly period). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 197 figure (10): partial autocorrelations for figure (11): partial autocorrelations for influent bod5 series influent tss series figure (12): frequency histogram for figure (13): frequency histogram for transformed series of influent bod5 transformed series of influent tss al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 198 figure (14): regression of influent of bod5 on the influent of tss. figure (15): regression of influent of bod5 on the logarithm transformed influent of tss. figure (16): regression of transformed logarithm of influent of bod5 on the logarithm transformed influent of tss. 50 75 100 125 150 175 200 225 250 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 in fl u e n t o f b o d 5 ( m g /l ) transformed logarithm of tss (mg/l) 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 t ra n sf o rm e d l o g a ri th m o f in fl u e n t o f b o d 5 transformed logarithm of influent of tss. 50 75 100 125 150 175 200 225 250 50 75 100 125 150 175 200 225 250 275 300 325 in fl u e n t o f b o d 5 ( m g /l ) influent of tss (mg/l). al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 562 improvement of surface hardness by ball milling technique for carbon steel (ck 45). abdul wahab ahmed daud m.sc. mechanical engineering. technical engineering college baghdad e. mail: wahabahmedaa@yahoo.com received 23 october 2012 accepted 5 jun 2014 abstract this research is devoted to study the effect of ball milling technique to improve the surface hardness of carbon steel (ck 45) die guides. this process depends on a rotating cylinder with number of certain size steel balls. experimental works are carried out on guides rods with (15 mm) diameter, and (35 mm) length processed on laboratory ball mill. the factors those studied in this process are rotating speed, and time. the surface hardness is recorded before and after the processing. the results show that the best surface hardness is (86.11 hv) obtained with ball size (5 mm) diameter rotate with (30 rpm) for (90 min.) processing time. الخالصة في هذا البحث استخدمت تقنية طاحونة الكرات المتدحرجة لتحسين الصالدة السطحية لعمود دليل قالب التشكيل من الصلب (. تعتمد هذه العملية على دوران اسطوانه وهي محملة بعدد من الكرات بحجم محدد مصنعة من الصلب. تم ck45الكاربوني ) . وقد تم دراسة العوامل المؤثرة منها سرعة الدوران (mm 35)وطول (mm 15دة بقطر )إجراء التجارب العملية على أعم والزمن. وقد تم قياس وتسجيل قيم الصالدة السطحية قبل العملية وبعدها. وقد أظهرت النتائج بأن أفضل صالدة سطحية هي (86.11 hv) بقطر مقداره تم الحصول عليها بإستخدام حجم كرات(5 mm) عة دوران للصندوق مقدارها وسر(30 rpm) ..(.min 90)خالل زمن مقداره key words: die guide, surface hardness, ball mill, guide rod. introduction stability in engineering structures is an important factor which must be considered to ensure the safe usage of parts against failure , this factor limits the ultimate load permitted before failure occurs, therefore it takes a great important in structural engineering especially dies technologies engineering. the prior studies achieved due to this problem deal for long time with elastic behavior of structure which finally caused failure .the later studies considered the plastic behavior of structural materials. in both cases the deflected part in structure provides a weak point finally causes the failure. mailto:wahabahmedaa@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 566 when a column is subjected to increasing compressive load, buckling side-way of the part will occur according to each of the following: 1. the amount of increasing load. 2. excessive length of column. 3. the properties of materials used. 4. the eccentricity of the applied load. therefore, there is a need for tool to improve the buckling resistance to increase the permitted load of materials. this research tries to test a method to increase a critical buckling load for die guide of (ck 45) steel. ling and wen (1998)[1] studied the structural strength and crushing behavior of single and bi-material stub columns subjected to dynamic loads. this research studies the local and post buckling behavior of the stiffened and unstuffed end compression elements under dynamic loading conditions with different strain rates. the results showed that the strength of stub columns depends on the material yield strength, the width to thickness ratio and the type of compression element, and the strain rate used in the test. wang &cao (1999)[2] has studied the buckling in sheet metal forming , prediction and prevention of side – wall wrinkling are extremely important in the design of tooling and process parameters in sheet metal forming processes. arif & urel (2005)[3] has studied the buckling analysis of slender prismatic columns with a single non propagation open edge crack subjected to axial loads has been presented ,he found that a crack located in the section of maximum bending moments causes the largest decrease in the buckling loads. also al – jubori (2005)[4] has showed that compression buckling stresses under static loading are higher than those under dynamic loading . van & s. pei (2006)[5] has studied the buckling reliability of deteriorating steel beam ends. the results of a study whose objective was to develop reliability charts for buckling of deteriorated steel beam ends based on state of the art measured truck load statistical modeling procedures was presented. saha& banu (2007) [6] presented a method of identifying the buckling load of a beam column based on a technique named multi – segment integration technique. this method has been applied to a number of problems to a certain its soundness andaccuracy. they consider a boundary value problem for the beam column equation. shengbin et. al (1998)[7] dealt with the elastoplastic large deformation analysis of short cylinders subjected to compression and bending. in the analysis, a type of four– node doubly curved shell element was employed .both the initial deflections and residual stresses were taken into consideration. barbero (1999)[8] studied the pultruded structural shapes as columns of intermediate length for which the global and local buckling loads are close. interaction between the two buckling modes is accounted design by an empirical interaction constant. theoretical / numerical prediction of such constant presented in this paper. juhas (2003)[9] presents a fundamental information about realized experimental and theoretical research and introduces a new calculation conception for determination of the buckling load – carrying capacity for compressed steel elements with hybrid cross sections. hilton (2006)[10] studied the dynamic response of linear viscoelastic temperature dependent prismatic columns under axial compressive loads and due to thermal stresses and moments .creep buckling instabilities and probabilities of material failures are analyzed to determine column life or survival times. optimal designer materials are studied to minimize thermal stress and axial load effects while concurrently lowering failure probabilities and extending survival times. oihoff & seyranian (2008)[11] developed a mathematical formulation of column optimization problems allowing for bimodal optimum buckling loads. the columns are continuous and linearly elastic, and assumed to have no geometrical imperfections. the method of ball milling technique is a cold work process. in this process the work piece surface is impacted repeatedly with a number of cast steel balls, at a high velocity which make al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 562 overlapping indentation on the surface causing a slight plastic flow and stretching of the surface metal to depth of a few hundredths of a millimeter using ball sizes that range from (0.125-5) mm in diameter. the stretching of the outer fibers is resisted by those underneath, which tend to return them to the original length, thus producing an outer layers having a compressive stress while the below are in tension .this action causes improving the mechanical properties of the work piece by increasing the surface hardness which is important to withstand failure due to buckling or even breaking. in addition to increase the stress corrosion resistance, reducing porosity in non – ferrous castings, improving surface wear ability as on gear teeth, improves the oil retentively of same surfaces [3]. experimental work the ball mill tests are achieved on a machine as shown in figure (1). the internal shape of the container is hexagonal. due to the rotating an impact action will be generated. the working factors such as drum velocity, time of processing and balls size can be controlled. the size of balls is fixed on (5 mm) .the guide rods diameter is (15 mm) as shown in figure (2). two sets of tests are achieved as follows: 11 st . set includes variable rotary speeds 20, 25, and 30 rpm. with processing time of 30 minutes. 22 nd . set includes variable processing times 30, 60, 90 minutes with rotary speed of 30 rpm. figure (3) shows the microscope which is used for measuring the microstructure of tested rods as shown in figure (4). tables (1 & 2) show the mechanical properties and chemical analysis of (ck45) respectively, and table (3) shows the experimental tests factors (drum speed and processing time). vickers hardness testing: before and after the processing the specimens are tested for surface hardness and the depth that is affected by this treatment as shown in table (4) by using vickers hardness tester with (250 gram) load as shown in figure (6). results and discussion table (3) represents the measured surface hardness before and after the 1 st . set of experiments which includes the variable rotary speed with (5 mm) diameter balls and a processing time 30 min., while table (4) shows the results of surface hardness with the same ball size and a fixed drum speed of (30 rpm) at a variable times (30, 60 and 90 min.).the die guides normally represent essential components in production dies. the job of these guides is to maintain the movement of the punch in the center line towards the die opening. to avoid failure (bending or probably breaking ) of guide within pressing operation, the guides must be selected as a steel metal with a sufficient surface hardness , so this research tries to use a balls indenting cold working process to attain a sufficient guide surface hardness. there are many methods used for developing this parts as mentioned in prior researches. in this research the plastic work that can be achieved by balls attack on the surface grain structure of steel rod due to compression action of indentation of the balls on the surface. these changes in the grains shape shall generate a strain hardening and as a result causes increasing surface hardness. the thickness of affected layer gradually decreased as depth increased figure (4) shows the layer thickness that is affected by balls attack. table (2) shows the hardness values changes which are decreased as the depth increased, and the results also show that the hardness is returned back to the as received rod al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 562 hardness in the depth of (600 micron) that is means the hardness layer thickness is equal to (400 micron). the results which obtained from the tests showed that the surface hardness is developed generally and they referred to that the surface hardness is direct proportional with both the drum speed and processing times with fixed other factors as shown in figures (7 & 8), and the best hardness number is obtained with (30 rpm) drum speed and (90 min.) processing time which is equal to (86.11 hv). conclusion the increasing of surface hardness by balls indenting cold working method which is achieved on ck45 die guides gave good results so this process may be considered as a developing tool in surface hardening fields. references [1] p. c. ling and y. w. wen, “the structural behavior of homogeneous and hybrid stub columns under dynamic loading conditions”, j. of thin walled structure, vol. 31, no 4, 1998. [2] x. wang and j. cao, “on the prediction of side –wall wrinkling in sheet metal forming process”, international journal of mechanical science, vol. 42, 1999. [3] m. arif and g. urel, “buckling of slender prismatic columns with a single edge crack under concentric vertical loads”, turkish j. eng. sci., vol. 29, 2005. [4] k. h. al – jubori, “column lateral buckling under combined dynamic loading”, phd thesis, university of technology , technical education department , (2005). [5] j. w. van de lindt and s. pei,”buckling reliability of deteriorating steel beam ends”, electronic journal of structural engineering, vol. 6, 2006. [6] g.saha and s. banu,”buckling load of beam-column for different end conditions using multi-segment integration technique”, arpn, j. of engineering and applied sciences, vol.2, no.1 ,2007. [7] g. shengbin and u. tsutomn,”ductility evaluation of steel bridge piers with pipe sections”, j. of engineering mechanics, vol. 124, no. 5, 1998. [8] e. j. barbero,”prediction of buckling – mode interaction in composite columns”, engineering science building , west virginia university, 1999. [9] p. juhas, “buckling load-carrying capacity of hybrid thin-walled compressed steel elements”, 16 th . asce, engineering mechanics conference, july 16-18, 2003, university of washington seattle. [10] h. h. hilton,”designer vesioelastic materials tailored to minimize probabilistic failures for thermal stresses induced dynamic column creep buckling”, j. of thermal stresses, vol. 29, 2006. [11] n. oihoff and a. p. seyranian, “bifurcation and post-buckling analysis of bimodal optimum columns”, international j. of solids and structures , vol. 45, 2008. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 562 [12] c. w. wegst, “key to steel”, verlag stahlschlussel wegst gmbh, 1986. table (1): the mechanical properties of (ck45) [ 12 ] modulus of elasticity gpa. elongation (%) ultimate strength mpa yield stress mpa material 205 ≥18 590-710 355 ck45(din) table (2): the chemical analysis of (ck45) phosphor % silver % silicon % manganese % carbon % steel 0.035 0.030 0.40 0.50-0.80 0.42-0.50 standard (din) 0.034 0.027 0.4 0.570 0.453 experimental table (3): represents the results experiments factors sample drum speed (rpm) processing time min. s1 20 30 s2 25 30 s3 30 30 s4 30 30 s5 30 60 s6 30 90 table (4): vickers micro hardness numbers with a load of 0.25 kg.* hv at samples 600 mm 400 mm 200 mm 78.13 79.00 79.14 s1 78.15 80.50 82.67 s2 78.13 81.40 83.22 s3 78.14 81.26 83.22 s4 78.92 82.00 84.13 s5 79.10 83.21 86.11 s6 *hv = 78.12 before hardening. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 522 figure (1): represents the ball mill equipment that is used in the process, (a) the hexagonal drum, (b) the electrical motor, (c) the gear box, (d) is the structural frame. figure (2): represents the tested rod that is used in the test, figure (3): optika e plan (40×0.65) microscope that is used in the testing. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 522 figure (4): shows the nonhardened microstructure of this alloy.(400x) figure (5): shows the hardened microstructure of (ck45), (x500). figure (6): vickers hardness tester, al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 525 figure (7): the relation between surface hardness of guide and drum speed. figure (8): the relation between surface hardness of guide and processing time. 78.5 79 79.5 80 80.5 81 81.5 82 82.5 83 83.5 0 5 10 15 20 25 30 35 h a rd n e ss ( h v ) drum speed (rpm) 83 83.5 84 84.5 85 85.5 86 86.5 0 10 20 30 40 50 60 70 80 90 100 h a rd n e ss ( h v ) time (min.) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 284 control of flexible robot using vision sensor measurements mohammad najeh nemah al-furat al-awsat technical university, engineering technical college-najaf \ iraq mohammed.najeh85@yahoo.com received 8 march 2015 accepted 5 july 2015 abstact the control of lightweight flexible robot using delayed measurements (i.e. vision sensor measurements) and moving along predefined paths is the focus of this work. the flexible robot dynamics is derived on the basis of a lagrangian-assumed modes method. noised and delayed tip deflection vision measurements are used beside the base tracking position for state variables estimation process. in order to generate the required control inputs a special state estimation approach is proposed to overcome noise and time delay and noise problems in the measurements. two state estimators are suggested for each of the measurements, and the states resulted from these two estimators are combined in order for the end effector to follow the desired response. the one link flexible arm prototype dynamic model is chosen for developing a case study. extensive simulation results are illustrated and discussed. keywords: flexible robot, state estimation, vision measurements. قياسات حساس الرؤيا السيطرة على روبوت مرن خفيف الوزن باستخدام محمد ناجح نعمة نجف / العراقال -جامعة الفرات االوسط التقنية/ الكلية التقنية الهندسية الخالصة مسار محدد مسبقا يا( و حركته حول ؤالسيطرة على روبوت مرن خفيف الوزن باستخدام قياسات التأخير )مثل قياسات حساس الر . (lagrangian-assumed modesهو محور هذا العمل. معادالت حركة الروبوت المرن اشتقت باالعتماد على طريقة ) للتشوه في الطرف العلوي للروبوت استخدمت بجانب اساس عمله في تعقب الموقع و تأخير الوقت في قياسات الرؤيا الضجيج وقت ،الضجيج للتغلب على حالة خاص تقدير اسلوبلغرض خلق مدخالت السيطرة المطلوبة اقترح لعملية تقدير متغيرات الحالة. متغيران لكل نوع من القياسات، و المتغيرات الناتجة من هذا المقترح جمعت تم اقتراح و مشاكل الضجيج في القياسات. التأخير دراسة حالة. وبعدها وضحت و لتطويرذراع روبوت مرن واحدة فقط اختيرت كموديل ديناميكي .االستجابة المطلوبة لمتابعة نوقشت نتائج المحاكاة الواسعة النطاق. .حساس الرؤيا، حالة تقدير اسلوب، روبوت مرن الكلمات المفتاحية: mailto:mohammed.najeh85@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 285 introduction the design of mechanical arms results in a high weight to payload ratio. a successful method to achieve advantages such as lower cost, higher speeds, better energy efficiency and improved mobility; can be fulfilled by using of lightweight robots. in this case, the control is one of the critical points to an effective use of flexible robot arms. as a matter of fact in flexible robots more complex dynamics involved by the flexibility distributed along a lightweight flexible links. in order to achieve a successful control synthesis; an accurate dynamic model for the flexible manipulator is required. the recursive lagrangian assumed modes method proposed by (jean, 1998) [1] is an efficient and complete modeling technique. the result of this method is a number of generalized coordinates, and then state variables will be used for control purposes. the control objective is not just to drive the manipulator to a specific point and stabilize the vibrations. the controller should concern about the specified path to follow. for a single link flexible arm, an optimal control approach is candidate to succeed (luca, 2003)[2]. the nonminimum phase property of flexible robot have not addressed in pseudo link concept associated with the tip output which is introduced in (luca, 2003)[2]. in order to deal with the exact tracking problem many researchers have been proposed the noncausal controllers for the purpose of trajectory tracking. the goal of this paper is to present an approach to the control of flexible manipulators moving along predefined paths, based on state feedback theory using visual measurements. a similar approach has been proposed by several researchers. the early experimental work in this area (rush et. al, 2002)[3], among others, aim at the end-point regulation problem based on the vision measurements. (victor et. al, 2000)[4] studied the input-state feedback linearization problem and showed that the system is not in general linearizable, however it is input output linearizable. to this end, the tip positions cannot be selected as the visual outputs due to the instability of the unobservable dynamics associated with such choice of outputs. (mallikarjunaiah et. al, 2013)[5] focused on the end-point control of a single flexible link which rotates in the horizontal plane by keeping the rotate angle of the flexible link at desired position and eliminate the oscillation angle of end effectors, the dynamic model is derived using a lagrangian assumed modes method based on euler–bernoulli beam theory. (rasheedat et. al, 2012)[6] developed a simple and efficient adaptive control scheme to automatically tune pd control gains for two-link flexible manipulator, the manipulator is modeled using lagrange and assume mode method. the adaptive algorithm is developed for hybrid pd-pid controller in which the pd controller is for rigid body motion control and the pid is for end-point vibration suppression. the model of linear quadratic controller design technique was controlled by using state space approach and the performance of single link manipulator in dynamic nonlinear torque condition was studied in (gamasu, 2014)[7]. a sensor fusion method for state estimation of a flexible industrial robot is developed in (axelssona et. al, 2012)[8], by measuring the acceleration at the endeffector, the accuracy of the arm angular position, as well as the estimated position of the endeffector was also improved, the al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 286 extended kalman filter and the particle filter are proposed as a solutions to the bayesian problem estimation formulated. it must be mentioned for control purposes that the full state availability is assumed. in fact the flexible link variables can be measured using strain gauge, but the variables derivatives’ cannot be measured but derived through a reconstructing another dynamic system as in (somolinos et. al, 2002)[9]. in this contribution it is assumed that one of the output signals of the system is suffered from noise and time delay measurement (e.g. camera measurements). in order to estimate the states based on two different types of measurements, two state estimators are designed. the first one is leunberger observer to estimate states using base tracking motor signal and the second is a kalman filter for the tip deflection noised and delayed signal. the paper is organized as follows: the mathematical model derivation will be presented, in the next section. the state estimation process will be detailed later. after that the control approach is presented. then the case study parameters and simulations will be discussed in details. finally, some conclusion regarding this work addressed in the last section. mathematical modeling of flexible robot the dynamic model of flexible link with a tip mass robot shown in figure (1) is derived in this section, where the motion of the robot is assumed as a rotation on a horizontal plane and the deflection occurs due to the movement of the link. nonlinear equations of motion for a flexible manipulator can be successfully derived using the recursive lagrangian approach outlined by (luca, 2003)[2]. this can be done by computing the kinetic energy, and the potential energy. the total kinetic energy and total potential energy of the system can be found by adding up those of various components of the system as:                       p l h ke t p ke l t ke h t ht rrmdxxpxpjrrmke 22 0 2 111 )()( 2 1  (1) y x figure (1) : kinematics descriptions for a flexible one-link. manipulator. o al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 287            l t dx dx xwd eipe 0 2 2 2 )( 2 1 (2) where lplh peandkekeke ,,, represent the kinetic energy of hub, link, payload, and elastic energy of link respectively, and hhp jandrrwmmie ,,,,,,,, 21  represent mass per unit length of link, modulus of elasticity of material, moment of inertia about z-axis, payload mass, hub mass, deflection of the link, components of kinematics vectors and hub inertia respectively. having the kinetic and potential energies of a typical element of an arbitrary link mass and stiffness matrices and load vector of the flexible link can be found by applying lagrange's equations. (3) (4) n is the number of links, and ei n is the number of flexible modes included. for a flexible one link manipulator the dynamic equation of motion is formulated by using eqs. (3 and 4) as: (5)      f k qqfqqm i         0 ,  (6) where     fqqfkqm ,,,,  are the mass, stiffness matrix, coriolus and centrifugal vector, and load vector respectively. q is the rigid and flexible displacements variables, and     n mmmm 11211 ,  . the components of mass matrix  qm , stiffness matrix k , and load vector in eq. 6 are functions of elastic deformations, elastic velocities, and nonlinear terms including rigid body degrees of freedom and their time derivatives. therefore, the dynamic equations of motion of one-link flexible manipulators are nonlinear. two modes of vibration are used in this work (i.e. 2n ) to describe the def1ection of link; so in this work t q ][ 21  . the summation of 21 and,  with each of nif ll t i ii ,,1                   ninj ll t ei ijij ,,1,,10                                                                         00 00 ,,, ,,, ,, ,,              i tt kf f mm mm     al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 288 coincides mode shape 21 and,  represents the value of w at each time instant. the dynamic model of the one link flexible arm with reference to the lagrangian dynamic equations is presented. dynamic state variables estimation flexible robot linear dynamic model. the nonlinear flexible-link system is not in general input-state feedback linearizable, however the system is locally input-output linearizable. for the sake of observer and controller design; the dynamic model is linearized about the operating point of the robot system. hence for designing state space model state variables based on eq.(6) assumed as, t ][ 2121   , and the dynamic state space model can be reformulated as: ),( )()( uh ugf     (7) taylor series expansion is used to linearize the state space dynamic model according to these conditions for an autonomous system )(so,0  fu  . the model is linearized about the operating point which is found out by solving the following equations 0)(0   f . after some mathematical simplifications for eq.(7), the linear state space model becomes (tewari, 2002)[10] udc uba     (8) using the eq.(5), the linear state-space matrices are found out to be,         0 0 1 km i a ,           qm b t 1 000 ,  tq 001 , 0d the base motor angle and tip deflection of the link are taken as output,               0000 000001 212 1 lxlx c c c  in this paper, it is assumed that the first output is free of noise and time delay. on the contrary, the second output is disturbed by noise and time delay (camera measuremnts), based on these assumptions the output equation can be rewritten as:                          )(0000 000001 )( 212 1 tt lxlx , here  , represent the time delay and the noise in the measurements respectively. observer design. for this study, it is suggested that the flexible robot system is observed with two types of sensor: motor sensor the base position, camera sensor to observe the tip position of the robot. the vision al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 289 data, which provides direct measurements of the deflection with respect to inertial coordinate, is proved to be a good substitute for strain gauges. related to the eq.(8), two different measurements are used. practically there will be time delay and noise in the all types of measurements; here the delay and the noise for the motor signal are neglected in comparison with the camera signal. due to the limitations of the sampling rate, and the resolution of the camera to detect all modes of the system; two different observers are designed to estimate the dynamical behavior of the system. the first one is a standard one, while the second one is used not only to estimate the states, but also for time delay compensation. this contributes significantly to the beam tip deflection estimation using the vision sensor. for the non-delayed measurement, the states are estimated using classical observer approach (heijden et. al, 2004)[11] as   111111 ˆˆ  kubcka  (9) with tt rcpk 1111  and 1 p as the solution of the riccati equation described as 0 111 1 11111   pcrcpappa tt (10) here 1  and 1 r are positive definite weighting matrices for the non-delayed states and measurements respectively. kalman filter design. the advantage of using the camera as a tip sensing device is the direct inertial measurement. the disadvantage is a delayed and noisy measurement signal. the delay is due to the time used in the vision processing and video signal transmission. in this section the method of defining states using an augmented predictor for the delay and noise compensation is described. here, an augmented kalman filter is proposed for the delayed estimation. according to (heijden et. al, 2004) [11], and assuming that the estimated states are delayed by  . the kalman filter equation can be written as   222222 ˆˆ  kubcka  (11) where tt rcpk 2222  and 2 p is the solution of the riccati equation described as 0 222 1 22222   pcrcpappa tt (12) here 2  and 2 r are positive definite covariance matrices for the noised-delayed measurement. to remove the delay effect from the estimated states, a function g is defined as al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 290 ubgag  (13) and the non-delayed state estimate can now be found (roberts, 1986)[12] as )]()(ˆ[ˆ 22    tgteg a (14) however, in practical implementation the states of the system can be estimated from different measurements by combining all of the corresponding state variable estimates. the states from the second estimator are combined with the states of the state observer, which are estimated using the full observer using the minimum mean-squared error i ̂ with ni pq pq iiii iiii i 1 ˆˆ ˆ ,, 2,1,       . (15) here n denotes the number of modes. an optimal estimation can be achieved, when they are combined properly. the derivation process of ii q , and ii p , are explained in detail in (roberts, 1986)[12]. note, that the subscripts '1' and '2' in the states denote cases that the states are estimated based on measurements '1' and '2', respectively. the schematic diagram for the estimation approach is shown in figure (3). controller design for a single flexible link the mass matrix is only a function of deflection variables, which are quadratic type nonlinearities. thus a single link may well approximate a linear system, while this is not true in the multi-link case. in spite of this fact, the simulations conducted with a single link case provide a basis for multi-link investigations, since both cases suffer from the undesirable nonminimum phase property. this property shows up when the controlled output is the end-effector position. the less difficult problem of end-point stabilization may also become troublesome, although not impossible, because of the non-minimum phase nature. the controller design for single link flexible manipulator describe in the figure (2). there are two output feedback signals and return to the observer and kalman filter respectively. after the observer processing the input signal generate the first combiner input signal ̂ , while the kalman filter output signal is the second combiner input signal ̂ . �̂� 𝒕 �̂� 𝒕 𝝉 𝒚𝟏 𝒕 𝒚𝟐 𝒕 𝝉 �̂� 𝒖 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 291 figure ( 2): controller design for single link flexible manipulator. the linearized model eq. (8) is used in this work to design the state feedback controller for the flexible robot system. the control input based on the linear quadratic regulator can be written as: ̂gu  . (16) here c t c pbrg 1  is designed (tewari, 2002)[10] to minimize the quadratic cost function:     0 uruqj c t c t  . (17) where cc rq , are positive semi-definite matrices and cp is the solution of the associated riccati equation 0 1   ccc tt ccc t qpbrbpappa (18) simulation and results the mathematical dynamical model of the lightweight flexible robot as well as the controllers have been developed in matlab \ simulink for simulation the structure shown in figure (2). the desired output trajectory used this work is higher order polynomials are sometimes used for path segments, this polynomial is quintic polynomial:   5 5 4 4 3 3 2 210 tatatatataat  , the solution is provided from robotics toolbox (corke)[13]. the initial conditions of the trajectory are chosen equal to zero in the start of the motion. the initial condition of the states are as follows  t000001.005.000  . it is assumed that the link are deformed before the start of the robot motion in order to ensure the capability of the estimation process in detecting the change in the states even if the estimator has no information about the initial conditions of the system. the flexible link physical parameters are as follows: 1 m length, 1x10 -4 m 2 cross sectional area, the first and second natural frequencies are: 2.12, 14.3 hz, ei=54.6 n.m 2 , ρ=7850 kg/m 3 . two set of results are presented in this section, first include the simulation when the time of the robot motion to reach the desired angle is 2 sec, the second set when the time is 3 sec. the set of the estimators’ gains resulting from the design process are:  3463 1 10644.101059.941035.15445.47581.40501025.14 k  013.81012810799003.2108740.1257 646 2   k . the state feedback gains according to procedure addressed earlier are  2076.06108.04597.00578.11208.11g . the desired motion of the link is addressed in figure (3); start from zero and tend to 90 degree in 2 and 3 seconds respectively. in order to compare the behavior of the designed system, a pd controller is also designed and simulated for the single flexible link robot. due to the nature of the flexible robot dynamics (i.e. a minimum phase system), the uncontrolled motion results are not presented. the time delayed and the noised signals can be seen in figure (4). this signal and the link rotation angle output signal are used for estimation process. the delay in the tip deflection output signal is variable value, in practical al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 292 applications the delay can be assumed as constant. the error in the estimation process due to the unknown initial conditions are shown in figures (5), for the motion time 2 sec. it can be easily noted that the estimators can construct the states of the system based on the output signals very quickly. the tip displacement and the input torque for proposed state feedback and pd controlled motion are shown in figures (6-9). in figure(6) the motion time is 2 sec; the tip deflection suppressed effectively after 1 sec. the same situation for the tip deflection in figure(8), although it is smaller but it required the same time for removing of the vibration from the tip. for the torque inputs and due to the change in the time of operation the required torque in 2 sec case is larger than the required torque for the 3 sec case figures (7 and 9). consequently the tip deflection and the input torque using the proposed state feedback control gave better performance in comparison with pd controller. conclusions in this work the estimation of the state variables of single flexible link robot model for control based on different types of measurements was studied. the dynamic model of flexible robot system is designed using assumed mode method. in order to deal with the different properties of those measurements, two state estimators are designed. the leunberger observer for the base angle of rotation measurements while the kalman filter is used for tip displacement noisy and delayed measurements, the two estimators work well. the states from the noisy delayed measurement are estimated with a good accuracy. the control of single link flexible robot based on the estimated states are simulated, and the results show good performance for the controlled behavior. the proposed estimation process will be implemented later experimentally for more complicated flexible systems. references [1] p. jean-claude, recursive modeling of serial flexible manipulators, journal of astronautcal sciences, 46-1(1998) 1-24, 1998. [2] a. de luca, robots with flexible links: modeling and control, outlined, roma university, department of informatics and systematic (dis), roma, 2003, online avialable: www.prisma.unina.it/cira03/ta_deluca2.pdf, 2003. [3] d. rush, d. robinett clark, e. richard, f. john, g. gordon, g. david, and s. dennis, flexible robot dynamics and control, ifac, international series on systems and engineering, 19, 2002. [4] o. victor and r. gamarra, a planar flexible robotic manipulator, division of mechanical engineering, college of engineering unesp, guaratingueta, brazil, cybernetic, 29, 5/6 (2000)787-796, 2000. [5] s. mallikarjunaiah and s. narayana reddy, design of pid controller for flexible link manipulator, international journal of engineering research and applications (ijera) issn: 22489622 www.ijera.com vol. 3, 2013. http://www.prisma.unina.it/cira03/ta_deluca2.pdf al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 293 [6] rasheedat and m. mahamood, direct adaptive hybrid pd-pid controller for two-link flexible robotic manipulator, proceedings of the world congress on engineering and computer science 2012 vol ii wcecs 2012, october 24-26, 2012, san francisco, usa, 2012. [7] r. gamasu, pre-load torque responses for flexibility in single link manipulator, m.tech research scholar, department of eee, sacet, cherala (a.p), india, 2014. [8] p. axelssona, r. karlssonb and m. norrl, bayesian state estimation of a flexible industrial robot, patrik axelsson, rickard karlsson and mikael norrlöf, bayesian state estimation of a flexible industrial robot, 2012. [9] j. a. somolinos, v. feliu, and l. sanchez, design, dynamic modeling and experimental validation of a new three-degree-of-freedom flexible arm, journal of mechatronics, 12 (2002) 919– 948,2002. [10] a. tewari, modern control design with matlab and simulink. john wiley and sons, 2002. [11] f. heijden, r. duin, d. ridder, and d. tax, classification, parameter estimation and state estimation, an engineering approach using matlab. john wiley and sons, 2004. [12] a. p. roberts, state estimation when some measurements are delayed, ima journal of mathematical control and information, 3 (1986) 299–310, 1986. [13] p. corke, robotics toolbox for use with matlab, more information http://www.petercorke.com. nomenclature h ke kinetic energy of hub. l ke kinetic energy of link. p ke kinetic energy of payload. l pe elastic energy of link.  mass per unit length of link. e modulus of elasticity of material. i moment of inertia about z-axis. p m payload mass. h m hub mass. w deflection of the link. 1 r , 2 r components of kinematics vectors. h j hub inertia. n number of links. ei n number of flexible modes included.  time delay in the measurements.  noise in the measurements. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 294 figure (3): the desired base angle. 0 0.5 1 1.5 2 2.5 3 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 sec. motion 3 sec. motion ɵ (t ) (r a d ) time (sec) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 295 figure (4): tip deflection signal; a) 3 sec. motion, b) 2 sec. motion. 0 1 2 3 4 5 6 7 8 9 10 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 (a) 0 1 2 3 4 5 6 7 8 9 10 -0.01 -0.005 0 0.005 0.01 0.015 (b) figure (5): displacement variables error q(t). time (sec) ɵ e ( ra d ) δ 1 e (m ) δ 2 e (m ) ψ 2 ( m ) ψ 2 ( m ) time (sec) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 296 figure (6): tip deflection (controlled motion) 2 sec. motion. figure (7): tip deflection (controlled motion) 3 sec. motion. 0 1 2 3 4 5 6 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 proposed controller pd-controller 0 1 2 3 4 5 6 -0.01 -0.008 -0.006 -0.004 -0.002 0 0.002 0.004 0.006 0.008 0.01 proposed controller pd-controller t ip -d is p la c e m e n t (m ) time (sec) t ip -d is p la c e m e n t (m ) time (sec) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 297 figure (8): input torque 2 sec. motion. figure (9): input torque 3 sec. motion. 0 1 2 3 4 5 6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 pd-controller proposed controller 0 1 2 3 4 5 6 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 pd-controller proposed controller f ( n .m ) time (sec) time (sec) f ( n .m ) al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 14 crack tip behaviuor under different load ratio with constant kmax assistant lecturer: muhanad hamed mosa university of al-qadisiya, college of engineering, department of mechanical engineering email: alafaq_eng@yahoo.com received 29 june 2014 accepted 25 november 2014 abstract in this paper, fatigue crack growth rate (fcgr) analyses were conducted on compact specimens of an aisi 4340 alloy to study the behavior over a range in load ratios (0.1 ≤ r ≤ 0.95) and constant maximum stress intensity factor (kmax) condition. previous study had indicated that high r > 0.7 and constant kmax test conditions near threshold conditions were suspected to be free crack-closure and that any differences were caused by kmax effects, from threshold to near fracture conditions. cracks in high-cycle fatigue (hcf) components spend a large portion of their fatigue life near threshold conditions. in order to characterize the evolution of damage and crack propagation during these conditions, fatigue crack growth rate (fcgr) data at threshold and near-threshold conditions are essential in predicting service life and in determining the proper inspection intervals. fatigue crack growth model, namely forman were examined, this model implicit the effect of r ratio and ease of curve fitting to measured data. the forman model may be suggested for use in critical applications in studying fatigue crack growth for different load ratios. keywords: fatigue crack growth rate(fcgr), crack closure, kmax effect, high-cycle fatigue (hcf) introduction cracks in high-cycle fatigue (hcf) components spend a large portion of their fatigue life near threshold conditions. in order to characterize the evolution of damage and crack propagation during these conditions, fatigue-crack-growth rate (fcgr) data at threshold and near-threshold conditions are essential in predicting service life and in determining the proper inspection intervals. based on linear elastic fracture mechanics, fcg rate (da/dn) data are quantified in terms of the stressintensity factor range k, at a given load ratio (r = minimum to maximum load ratio). the relation between k and da/dn was shown to be nearly linear on a log (k) log (da/dn) scale. the relationship becomes nonlinear when the crack approaches fracture [1] or when the fcg rate is very slow [2]. one of the significant mechanisms that influence crack-growth behavior is crack closure, which is partly caused by residual plastic deformations remaining in the wake of an advancing crack [3, 4], roughness of the crack surfaces [5], and debris created along the crack surfaces [6]. the discovery of the crack-closure mechanism and development of the crack-closure concept led to a better understanding of fcg behaviour, like the load-ratio (r) effect on crack growth. the crack-closure concept has been used to correlate crack-growth-rate data under constantamplitude loading over a wide range in rates from threshold to fracture over a wide range in load ratios and load levels [7]. difficulties have occurred in the threshold and near-threshold regimes mailto:alafaq_eng@yahoo.com al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 15 using only plasticity-induced crack-closure modeling [8]. in the low rate system, at and near threshold conditions, roughness-induced crack closure (ricc) [9] and debris-induced crack closure (dicc) [10]. the crack-closure concept has not yet been able to correlate data in the threshold regime, either from load-reduction tests at constant r or constant kmax tests. variations in the threshold and near-threshold behavior with load ratio cannot be explained from picc alone, but ricc and dicc mechanisms may be needed to correlate these data. the constant kmax test procedure [11] also produces what has been referred to as the ‘‘kmax effect”, in that, lower thresholds are obtained using higher kmax values [12]. compared with the constant r test method, constant kmax tests gradually decrease pmax and increase pmin to obtain a reduction in k as the crack grows. one advantage of this programming test method is that it is commonly considered to produce crack-closure-free data (r≥0.7). but constant kmax testing also produces data at variable load ratios (r) and fatigue crack growth thresholds at high load ratios (> 0.8). for steel alloys and larger kmax values, more dimpling and tunneling on the fatigue surfaces were observed [13, 16], as the threshold was approached. this behavior indicated a change in the damage mechanism from classical fatigue-crack growth to more of a tensile fracture mode due to the kmax levels approaching the elastic fracture toughness. but extensive literature data reviewed by vasudevan et al [14] and test data by marci [15] on a wide variety of materials do not show the socalled kmax effect. material and programming test procedure alloy steel are widely used in design of many engineering application, aisi 4340 has a favorable response to heat treatment (usually oil quenching followed by tempering). it also a good combination of ductility and strength when treated thusly and using many application such as; piston, pins, bearings, ordnance, gears, dies, pressure vessels. chemical composition and mechanical properties are shown in tables 1 and 2. the modeling and simulation are analyzed using glyph work software packages. modeling of fatigue crack growth data has enhanced the ability to create damage tolerant design philosophies. glyphwork , it is the special software for determine the crack initiation , propagation value with relationship number of cycle. the forman model was found to be the most appropriate model for the constant amplitude loading. therefore, the forman growth law implicitly models threshold and short cracks by applying a crack closure stress kcl expressed. the forman equation is a modification of the paris equation. typical mean stress effects in the threshold region. the forman growth law model is popular on account of its implicit modelling of r ratio effects and ease of curve fitting to measured data ,the onset of fast fracture and crack closure. the number of cycles to failure is the fatigue life (nf) and the form of cycles is illustrated in figure 1. most of time, the s-n fatigue determination is carried out through the use of fully reversed loading. this implies that loading is taking place about a zero mean stress. in this analysis, the material of the shell astm a533 steel has been used , for which the chemical compositions at room temperatures are listed in table 1. the cyclic and cyclic properties are listed in table2. in particular ,astm a533 is one such kind of steel which has applications in pressure vessels (astm standard v1.04). these steel types generally contain less than 0.25 wt % c and are unresponsive to heat treatments intended to form martensite, as strengthening is accomplished by cold work. the typically have yield strength of 585 mpa, tensile strength between 637 and 825 mpa ,and ductility of 20-25 % meanwhile , microstructure consists of ferrite and pearlite constituents. the data has been obtained from the tensile test machine in our lab. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 16 stress ratio has been crack growth behaviour , especially at high and low da/ dn. at high , for example, increasing r leads to an increase in kmax with respect to , and thus enabling kmax to be near to k1c . cleavage and inter-granular cracking frequently observed at high are predominantly tensile stress controlled fracture modes which are introduced more frequently with the increase of kmax with r. that is , a variation in r can promote a change in the rate controlling fracture mode. there are a number of extra factors. the majority of structures are subjected to val. during this type of loading ,various load interactions which may significantly alter the growth behaviour of a crack have been known to occur . the large effect of high loads on fcg has stimulated a lot of research , both experimental investigation as well as analytical studies. the significance of crack tip plasticity was easily recognised and it obviously suggested that the plastic zone size must be important for crack growth retardation. the retardation of the growth of a through crack is dependent on the thickness and yield stress of the material because the plastic zone size is determined by the state of stress ( plane strain or plane stress or intermediate situations ). this has been amply confirmed by the experimental results gathered. the promising application of the kconcept to predictions on fatigue crack growth under cal was drastically upset by the first experiments with overloads ( ols) in the cal test carried out. results and discussion fatigue crack growth (fcg) programming tests were conducted over a wide range in load-ratio conditions (0.1 ≤ r ≤ 0.95) and a constant kmax test. fig 3. shows the test data, which generally ranged from threshold to near fracture. at high rates, the asymptote to fracture, as expected, was a function of the load ratio r. in this regime, the critical stress-intensity factor range at failure, kc, is given by kie (1 r), where kie is the elastic fracture toughness or maximum stress-intensity factor at failure. thus, at higher r-values, a crack will grow to failure at lower values of kc. in the near-threshold regime, the r = 0.95 rates were slightly higher than the r = 0.9 rates at the same dk value. in the mid-rate regime, the r = 0.9 results gave slightly higher rates than the r = 0.7 results, but the r = 0.8 results agreed well with the r = 0.7 results. the results from the low r (0.4 and 0.1) tests showed the usually parallel shift with load ratio. but at low rates, the r = 0.9 test data agreed well with the constant kmax test data at low rates, which had r-values ranging from 0.7 at the start of the test to 0.9 near threshold conditions. the constant kmax test and most of the other tests had the same characteristic shape of the crackgrowth-rate curve in the threshold regime, except the results from the r = 0.1 test. fig. 3 shows a comparison of test data generated at r = 0.1 and 0.7 using the load reduction method. this method is basically a k-reduction scheme to maintain a constant load ratio. however the load-reduction test method has been shown to produce higher thresholds and lower rates in the near-threshold regime than steady state constant-amplitude data on a wide variety of materials. in addition, the load-reduction test method produces fanning with the load ratio in the threshold regime for some materials. the results from the low r (0.7 and 0.1) tests show the usually parallel shift with load ratio. to generate constant load-ratio data in the threshold and near-threshold regimes. it has been shown that the test method induces a load-history effect, which may be caused by remote closure. thus, the load-reduction test method does not, in general, produce constantamplitude fcg data. many well-known formulations for the effect of r-ratio have been proposed. can these equations be used to calculate the crack growth life of components subjected to constant amplitude loading (cal). most mean stress effects on crack growth have been obtained for only positive stress ratios, i.e., r ≥ 0. fig. 4 shows the variation of the crack growth rate versus the al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 17 corresponding crack length for different stress ratio for only positive values. the material displays significant r-ratio effect. with an identical stress intensity factor range, a higher r-ratio results in a higher crack growth rate. although the threshold was not experimentally measured, the tendency indicates that the threshold value of the stress intensity factor range increases as the r-ratio decreases. it observed that the fcg affected by different stress ratios. the increasing of stress ratio which means increasing the mean stress has tendency to increase the crack growth rates. conclusion fatigue crack growth rate (fcgr) analysis were conducted on compact specimens of an aisi 4340 alloy to study the behavior over a wide range in load ratios (0.1 ≤ r ≤ 0.95) and constant maximum stress intensity factor (kmax) condition. during a test at a load ratio of 0.7, these results imply that the r = 0.7 programming test had a significant amount of rack closure as the threshold condition was approached. while the r = 0.9 and kmax test results may have had a small amount of crack closure, and may not be closure free, as originally suspected. under the high load-ratio conditions (r ≥ 0.7). the constant r tests at extremely high r (0.9 and 0.95) were also performed and compared with the constant kmax test results. the constant r test results at 0.95 agreed well with the keff-rate data, while the r = 0.9 data agreed well with constant kmax test data in the low-rate regime. references [1] jm . barsom: j engng ind.vol. 1190–6. (1971), p.93 [2] jr aj .mcevily, w. illg: naca tn. 4394 (1958) [3] w . elber.vol. 37–45. (1970).p.2. [4] w .elber: astm stp. american society for testing and materials (1971). 22:23042, p.486 [5] n .walker, cj. beevers: fatigue engng mater struct. 135–48 (1979),p.1. [6] pc .paris, rj. bucci, et .wessel, wg. clark, tr .mager: astm stp 513. (1972),p. 141 [7] jr. jc .newman: the netherlands: delft university press. (1992) [8] jr jc .newman: astm stp-1372. (2000), p.227. [9] br.kirby, cj : fatigue fract engng mater struct.vol. 203–16. (1979),1. [10] s. suresh, zaminski, ro .ritchie:. metalltrans. vol. 1435–43.(1981), a12a [11] w .herman, r. hertzberg, r .jaccard: fatigue engngmater struct.vol. 303 (1988),p.11. [12] jk .donald, gh .bray, rw .bush: pa: american society for testing and materials. astm stp1332. (1999), p. 674 [13] ja. newman, wt .riddell, rs .piascik: astm stp-1372. (2009),p.63. [14] sw .smith, rs. piascik: pa:american society for testing and materials. astm stp 1372. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 18 (2000), p. 109 [15] ak .vasudevan, k .sadananda, louat: mater sci engng. a188. (1994),p. 1 [16] jr jc. newman, jb. jordon, el. anagnostou, d. fridline, d. rusk: in aging aircraft conference, phoenix, az. april (2008) table 1: chemical composition of aisi 4340 table 2: mechanical properties of aisi 4340 figure 1: symbols used with the cyclic stress and cycles al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 19 delta k ( mpa.sqrt m) 1.00e-09 1.00e-08 1.00e-07 1.00e-06 0 5 10 15 20 25 30 35 d a /d n ( m /c y c le ) r=0.1 r=0.4 r=0.7 r=0.8 r=0.9 0.00e+00 5.00e-09 1.00e-08 1.50e-08 2.00e-08 2.50e-08 0 10 20 30 40 50 60 delta k ( mpa.sqrt m ) d a / d n ( m /c y c le ) r=0.1 r=0.4 r=0.7 r=0.8 r=0.95 figure 2: fcg rate data at low and high stress ratio for load-reduction figure 3: fcg rate data for a constant kmax and different stress ratio al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 20 1.00e-09 1.00e-08 1.00e-07 1.00e-06 1.00e-05 10 15 20 25 30 delta k ( mpa.sqrt ) d a /d n ( m /c y c le ) r=0.1 r=0.4 r=0.7 r=0.8 r=0.95 figure 4: fcg with different stress ratio under cal al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 129 assessment of distribution coefficient to remove the radioactive pollution from wastewater by using bentonite clays salam khudhair abdullah nabeel h. ameen hydar k. esa environmental engineer environmental engineer environmental engineer hazmat and environmental research directorate iraqi ministry of science and technology abstract the technology of ion exchange is applied in batch operation for removing potassium-40 as from liquid solutions (prepared in laboratory by solved known amount of kcl in known amount of distilled water. a measured quantity of the ion exchange medium (bentonite clays) is mixed with radioactive solution containing potassium-40 in a suitable mixing vessel. the activity concentrations of liquid solution containing potassium-40 in the influent and effluent samples are measured by gamma ray spectroscopy system composed of a high purity germanium detector with 40% efficiency coupled to an 8192 channel personal computer analyzer. the amount of exchanger media required and the rate of exchange is determined by laboratory tests. the distribution coefficient for bentonite clays for removing k-40 in batch operation (0.104815 l/gm) is estimated by correlation line method, with a correlation coefficient between the observed and the predicted data of 96%. to ensure accuracy and reliability of the collected data, the 2χ test is used to measure deviations between the observed and expected k-40 activity concentration captured by the bentonite clays and passed through it. no significant difference is observed between observed and expected data at 5% significant level. the results indicate that the distribution coefficient can be used in predicting the amount of an ion exchanger media needed to remove potassium-40 with a certain decontamination factor. key words: distribution coefficient, radioactive pollution, k-40, batch system, bentonite clays. +$�� � ��/ ا��*.&�ت !�*�ام ��ب ا� 0 '� 6 ا� ز$5 2زا�� ا� . ث ا��12�� 7���� �� ��� �� �� ���� ���� ���� � �� ���� ���� ���� ����� ��� ���� ����� ���� �� �������� ��� ��!"�� #��$� �������� ��� ��!"�� #��$� �������� ��� ��!"�� #��$� %������ &������ #�' �� ������ #���� %������ &������ #�' �� ������ #���� %������ &������ #�' �� ������ #���� al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 130 %(� ��: ] =2p�� ا�� �دل أ��f$c� ��fys5ب ا�r if�xزا��f ا� �=�fy��م �x�y٤٠-ا) l�fة ) ا���gfا��� �fbا���� 'f�ا����� /f �qpا���ء ا�� / /� d�� / آ��ر$� ا� �=�y��م � �2� �$ً� s5ذا�5 آ��� �x �fدة ا�� �fدل . /f �fزو�� �f�آ� if�df= ���$c����2$] (أ �p وا���وي ��� ا� �=�y��م l ا�����ل ا� ) أw��ن ا�r ffy�2 ٤٠-��l ا���pس و ا�� � i�و��ء � . w�sf�$ ،�f ا��,�fز f/ آ�wfy ٤٠-=j d��س =�آ�a ا� �=�y��م �e ف�f�w2�� =���' أp= ام�x�y�5 �eر�xا���2ذج ا��ا-�� وا� � ����م ���� ا��p2وة 5()�ءة �e�2ات % ٤٠pد ا�� � �4xy �5�y�� '�� l i =� �$f z� ا. �x ] ��ة =��رب �x�y ' =�ز$l آ��� ا�� �دل أ��f$c� ا���f5��q و �fل ا�� �fدcت � / �gأآ �$�p= . [f$����2 f' ا���ز$�f�w> lfن ا�� و�fe أن � rزا�� ا� �=�fy��م �x�rوي ٤٠-ا���rf$ 0.104815 �f�� / ود�f�5 �f jوا���� zfy�pت أ���f��� :f�ام و�5 � f' ار= �fط f5�/ ا� ٩٦ .%x�yم ا��fy�=� �fدة ا�� �fدل ٤٠-�م ا-� �ر �l5 آ�fي ��f�pس �fل ا��c�ا �fت 5�f�/ =�اآ�af ا� �qfy�4 �5اf2�pا�� �f�آ� �$�fp= �f l$ا���ز ' � ' ا���ز$l، أ�yرت ا�km��2 إ�� أ (���� ا�x�yام � أc$��� ا���y�p وا���pرة �5ا���j �qyن . و�5 �ل إزا�� �/٤٠-ا�� �دل أc$��� ا��r �5��qزا�� ا� �=�y��م introduction potassium is a chemical element is commonly found in nature. it is present in soil and drinking water. it is also an essential element for the growth of plants and beings. the concentration of potassium is important in determining the quality of soil in applications such as greenhouses and agriculture. potassium salts are also a common component of fertilizers (hanna, 2002). of the three naturally occurring potassium isotopes, only k 40 is unstable, occurs to an extent of 0.017% in natural potassium, imparting a specific activity of approximately 800 pci/g (31kbq/kg). because of its relative abundance and its energetic β emission (1.3 mev), the radioactivity of k 40 is easily the predominant radioactive component in normal foods and human tissues. radionuclides that occur naturally in soil are incorporated metabolically into plants and ultimately find their way into the bodies of animals and human (eisenbud, 1973). annual limit on intake (ali) of radioactive potassium-40 by oral ingestion pathway is 300 ciµ ( us. nuclear regulatory commiss 2003). ion exchange is used in removing potassium-40 from radioactive liquid solution, the first application of ion exchange resins for the removal of radioactivity was developed for the separation of the fission products including the rare earth (nachod, 1956). ion exchange is a process in which mobile ions from an external solution are exchanged for ions that are electro statically bound to be the functional group contained within a solid matrix (iaea, 2002). the ion exchange technology is applied in batch operation, which involves vessels in which the exchanger particles are mixed with the liquid stream, followed by settlers in which the two streams are separated to be send later to other stages (nachod, 1956). a measured quantity of the ion exchange medium is mixed with the liquid waste in a suitable container. the amount of media required and the rate of exchange can be determined by laboratory tests or by calculation using the following equation (iaea, 2002): ( ) m v dfk d *1−= (1) where: kd is the measured distribution coefficient, df is the required decontamination factor, v is the volume of the liquid to be purified, m is the amount of the ion exchange medium needed to reach the required decontamination factor. for liquid volume of 1 liter, equation (1) is rearranged: df – 1 = kd * m (2) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 131 the slope of the line of linear relationship between k-40 decontamination factor minus one (df-1) and amount of clays used (m)(equation (2)) represents the distribution coefficient, and can be determined from the formula (volk, 1969): d k m dm x yx b = − == ∑ ∑ ∑ ∑ 22 )1(** (3) test for goodness of test: data observed and expected can be tested by statistical methods for deviations from some hypothesized values. 2χ is a measure of this deviation (volk, 1969): ( ) ( ) ∑ ∑ − == e eo ectation deviation 22 2 exp χ … (4) where o =observed frequency (or concentrations that indicated by measuring device), e=expected frequency (or concentrations indicated by the distribution coefficient formula). experimental work: 1 preparation of samples the radioactive solution containing potassium-40 is prepared in laboratory by mixing known amount of potassium chloride (kcl) to known volume of distilled water and use it as wastewater , the gamma-ray activity concentration of natural potassium in the influent samples is measured. certain amount of an ion exchange media ((0.5-4)gm bentonite clay) is added to the sample, the mixture is stirred for several minutes (15 min.) by magnetic stirrer, fig.(1). the gamma-ray activity concentration of the effluent sample is measured by the gamma-ray spectroscopy technique after treatment. 2 samples counting: a gammaray spectrometric system, figure (2) composed of a pure germanium detector with 40% efficiency (tennelec, usa), coupled to an 8192 channel personal computer analyzer (tandy, usa) is used in measuring k-40 activity concentration in the influent and effluent samples. energy and efficiency calibrations are carried out with a standard eu-152 source (iaea, vienna). the computer code gdr-4 was used to determine the activity concentration of potassium-40 in the samples (marouf, 2000). every sample is counted for 3600 s. results and discussion: radioactive potassium is used as a tracer in predicting radioactivity removal efficiency in batch tests. a synthetic radioactive wastewater is prepared by mixing measured amount of kcl with distilled water. the untreated water is contacted with the bentonite particles at different dosages in a suitable mixing vessel for sufficient period of time (15 min) to allow ion exchange process to occur between k-40 ions in the synthetic radionuclide wastewater and the h + and na + ions in the structure of bentonote clays. after completion of mixing time, the suspended matters are allowed to precipitate in order to separate the exchanged k-40 ions from the effluent samples. quantitative analysis by the gamma ray spectroscopy system indicates the k-40 activity concentration in the effluent samples. the quantitative analysis of the radioactive samples, both before and after contacting with a measured amount of bentonite clays, is given in table (1). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 132 the distribution coefficient is estimated by equation (2) to be the slope of the line of linear relationship (correlation line) between df-1 and dosage (m), figure (3). the assessed value is 0.104815 l/g. comparison between observed and predicted activity of k-40 captured within the bentonite clays as observed by measuring instrument and indicated by the distribution coefficient formula is shown in figure (4), with a correlation coefficient between observed and predicted values of 96%. the 2χ test is used to measure deviations between the observed and expected k-40 activity concentration captured by the bentonite dosage when mix with it. the influent k-40 activity concentration is divided into two groups: captured and passed activity, the observed concentration is that measured by the gamma-ray spectroscopy system, and the expected is that indicated by eq.(1). the estimated 2χ in table (1) for all the run experiments are found to be less than the tabulated 2χ value (3.841) for 5% significance level and one degrees of freedom. conclusions: (1) the use of a cation-ion exchange bentonite clays in a batch reactor was found to be an suitable technique for k-40 removal from polluted water. (2) to protect the public health from radiation hazards caused by contamination of water supplies by k-40, the concentration of k-40 in tap water (cin) must be reduced to the maximum permissible concentration (mpc). the amount of bentonite dosage (mg/day) needed to reduce concentration of k-40 in water to the (mpc) of k-40 in water can be well approximated by: 104815.0 1 v mpc c m in       −= (5) where v is the untreated water flow rate (l /day). good agreement is noticed between observed and predicted amount of exchange media dosage, with a correlation coefficient of 96%. references 1hanna instruments general catalog, hi, italy, 2002. 2eisenbud, merril, "environmental radioactivity", harcourt brace jovanovich publishers, academic press, new york and london, 1973. 3us. nuclear regulatory commission, "potassium-40", private policy, site disclaimer, last revised tuesday, august 05, 2003 (internet). 4nachod, f.c., jack schubert, "ion exchange technology", academic press inc publishers, new york, 1956. 5iaea, "application of ion exchange process for the treatment of radioactive waste and management of spent ion exchangers", technical reports series no.408, iaea, vienna, 2002. 6volk, w., “applied statistics for engineers”, mc-graw hill book co., 2 nd edition, 1969. 7marouf, b.a., “environmental impact of depleted uranium (du) contamination in iraq”, conference on the effects of the use of depleted uranium weaponry on human and environment in iraq, baghdad, 5-6 november, 2000. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 133 table (1): activity concentration of k-40 before and after the treatment by addition of selected bentonite dosages: concentration (bq/l) captured concentration (bq/l) passed concentration (bq/l) clays dosage (gm) input output observed expected observed expected 2χ 0.5 52.7 47.1 5.6 2.624 47.1 50.075 3.55 1 52.7 45.8 6.9 4.999 45.8 47.700 0.79 2 52.7 44.4 8.3 9.132 44.4 43.567 0.09 2.5 52.7 42.6 10.1 10.492 42.6 41.757 0.081 3 52.7 39.4 13.3 12.607 39.4 40.092 0.050 4 52.7 37.4 15.3 15.567 37.4 37.132 0.0065 figure (1): schematic the batch operation of ion exchange technology al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 134 figure (2): a gammaray spectrometry system 4.2 6.2 8.2 10.2 12.2 14.2 16.2 0.5122.534 dosage (gm) d f -1 figure (3): computation of kd by correlation line method al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 135 0 2 4 6 8 10 12 14 16 18 20 captured activity (bq/kg) 0.5122.534 bentonite dosage (mg) observed expected figure (4): comparison between observed and predicted amount of bentonite dosage required to achieve a certain decontamination factor. 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 37 السليكا وحجمه الحبيبي على المسامية الظاهرية و رملدراسة تأثير تغير نسبة مقاومة االنضغاط للمرشح السيراميكي ديوانيه -المعهد التقني /انسام علي هاشم الحسناوي 1024آيار 12ُقبل 1024شباط 22ُأستلم الخالصة لةوي ا الودا وص ثعون م المالوي الةو اام اص يو امو ا نةوبت البحث هو دااةوت ثور اا ان الهدف من هذ هوووذل المووو اد ثووا اةوووث داا موو اد ي ل وووت ةوو اام ا ت انثووو المالووح مةوو م ثا اله ها وووا م مووت ان ووو ا ثووا اةووث داا الاموو مثوو اف ووص اوواا الهوواال هووص اموو يا يا وومت اوو كل ن الد يووت ا اب نوو الا لةوو ا ( 150µm,125µm,100µm,75µm,50µm) ووودف ح ووو ا ل ةووو م امووو الةوووي ا ذلوووع بهووود عووويا الووو %35 الاو كل ن %65)مون الما نوت binderامو دف اة ةو ت ا و ت الو المو دف الااب وت sand 60% binder ) (sand 50 % 50% %40ا اب نوو الا ةوو ا( بنةووا م ثي ووت ) binder( )60% sand 40% binder binder ثوا اةوث داا ا وت الاوبه لوبا ال و ف وص ثلوا ) ةو ت( مون وا لبود ي 24( لمدف)ºc 110 نم ذ المالح ص دا ت حاااف ) النم ذ الم ثبا ت ة ت( من ا ثا اةث اا المة م ت م مت اان 1 ثاف ما ث ) ( ( 1200 حاق بدا ت حاااف ثووا الث عوو الوو الهنقووت بوو ن )نةووبت اموو الةووي ا ح ووا حب بوو الاموو ( الهمي ووتنثوو ب ا ثموو د يوو ال 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 37 ب لنةووبت لثوور ا نةووبت اموو الةووي ا ثاوو ن م مووت اان وو ليمالووي الةوو اام اص( )المةوو م ت اله ها ووت وووك ا الح وووا نقثهووو اد وووت موووم المةووو م ا اله ها وووا ب نمووو ثاووو ن نقثهووو اةووو ا موووم م موووت اانه ووو الحب بوووص يووو ال ووو او ال ا وووت الم ا ن ا وووت لينم ذ ح وووث نووود ا ووو دف ح وووا ال ةووو م ث ووو المةووو م ا ( ذلوع نود 41.328اله ها ت ثثحةن م مت اانه ح وث اههوا النثو ين ي يو مةو م ا ه ها وت ) ي يووووووووو م موووووووووت ( 50µm)( يعووووووووو ا ح وووووووووا ل ةووووووووو م الامووووووووو %60ي يووووووووو نةوووووووووبت لامووووووووو الةوووووووووي ا ) ( يابوووووووا ح وووووووا ل ةووووووو م %40( ذلوووووووع نوووووووديق نةوووووووبت نةوووووووبا لامووووووو الةوووووووي ا )11.831mpaانه ووووووو ) (150µm)الام الكلمات الدالة: المرشحات السيراميكية , نسبة الرمل , حجم الجسيمات , المسامية الظاهرية و مقاومة االنضغاط study the effect of changed the sand percentage and its particales size on apparent porosity& comprassive strength of ceramic filters ansam ali hashem al-hasnawy/technical institute-diwaniya abstract changed the sand the objective of this research is to study the effect of percentage on apparent porosity and compressive strength of ceramic filters. in this research, using ceramic raw materials to produced the filters. filters made from the raw materials (sand, kaolin, and calcium carbonate), which obtained from um urdhuma and aldeuechla in the west of iraq. sand was the basic material used to make filters. selective some of sand particle size (150µm, 125µm, 100µm, 75µm, 50µm), in addition to the binder material that consisted (65% kaolin + 35% calcium carbonate), in different weight percentage (60% binder + 40% sand, 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 37 50% binder + 50% sand, 40% binder + 60% sand) ), and used the semidry compaction to forming the laboratory samples the samples dried in (110 ºc) for (24 hours), and fired or sintered at 1200ºc for soaking time (1hour),then we extracted compressive strength and apparent porosity. the experimental result led to the relationships between (rate of sand, particle size of sand) and apparent porosity and compressive strength of ceramic filter. . increased the rate of sand increased apparent porosity, but it decreased compressive strength. ). increased particle size of sand decreased apparent porosity, but it increased compressive strength. the rustles show the maximum apparent porosity (41.328%) at the maximum weight percentage of sand (60%)), and minimum particle size of sand (50µm).the highest compressive strength( 11.831mpa) at lowest weight percentage of sand (40%), and maximum particle size of sand (150µm) . keyword: ceramic filters, sand percentage, particales size, apparent porosity, compressive strength الرموز االنكليزية الوحدة المعنى الرمز a مة حت م م النم ذ cm2 d ال ان ال ف g dr ق ا النم ذ mm do ق ا ال لا ال ا ص mm din ق ا ال لا الدا يص mm h ااث ع ال لا mm h ااث ع نم ذ اان mm m ال ان الملبم g s ال ان المهيل g 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 37 pc لمةي حث الاةاحم اان ا n p.v.a ب لص ن الاح t ةمع النم ذ mm (:introductionالمقدمة ) وووووووووووووووص م ووووووووووووووو ا الح ووووووووووووووو ف الم ثي وووووووووووووووت ةووووووووووووووو ا يا نووووووووووووووو ممووووووووووووووو موووووووووووووووه filtersثووووووووووووووود المالوووووووووووووووح الح وووووووو ف مب لووووووووواف اموووووووو وووووووووص مالوووووووووح ثن ووووووووت م ووووووووو ل اللوووووووواا ي المالوووووووووح الثوووووووووص ثمنووووووووم ثيووووووووو ث المووووووووو ي ثيووووووووووووووووووووووووووووع المةووووووووووووووووووووووووووووثهميت لا ووووووووووووووووووووووووووووم ا وووووووووووووووووووووووووووو ف ا ا الماوووووووووووووووووووووووووووو ن العوووووووووووووووووووووووووووون ت ي الهوووووووووووووووووووووووووووو ا candles قنوووو ا circular plates)عوووو ي دا ا ووووت يلووووا ا م ثي ووووت المالووووح ا ووووذ لووووذا الوووووووو حا ( ينوووووووو اع م ثي ووووووووت ب ا ثموووووووو د يوووووووو نوووووووو ع الموووووووو م المووووووووااد ثdisksيقووووووووااو tubesين ب ووووووووا )اوووو ا ةوووو ( ي حةوووووا الموووو دف الثوووووص ثوووود وووووص ثعوووون ها ا لمالوووووح النةوووو ت )يل ووووو ف ال وووون يل ووووو ف النووووووووووووووووووو ي ن ال مووووووووووووووووووو ا ( المالوووووووووووووووووووح ال اق وووووووووووووووووووت المالوووووووووووووووووووح الةووووووووووووووووووو اام ا ت )مالوووووووووووووووووووح silicon ا اب ووووووود الةوووووووي ا نsilica الةووووووو ي ا alumina اال م نووووووو porcelainالب اةوووووووي ن carbide لا اب ن اcarbon ا اه من الم اد الم ثي ت ) اموووو هووووو مهيووووو ا وووووص ا دب ووووو ceramic filters ثثنوووو الدااةوووووت الح ل وووووت المالوووووح الةوووو اام ا ت الهيم وووووت ان المووووو اد الةووووو اام ا ت هوووووص بووووو اف ووووون ماابووووو بووووو ن الهن عوووووا المهدن وووووت النمهدن وووووت مههمهووووو لهووووووو بن ووووووووت بي ا وووووووت مه وووووووودف carbides الا اب وووووووودا nitrides النثا وووووووداoxidesمووووووون ا ا ةوووووووو د ان ا وووووووووووو ف المالووووووووووووي الةوووووووووووو اام اص ثاب هوووووووووووو ي اعووووووووووووا ا ن ووووووووووووت ي ثةوووووووووووو هم ت ي ملووووووووووووثاات ب نهموووووووووووو ceramicfilter ثهثموووووود يوووووو ميووووووت موووووون اله اموووووو يهمهوووووو ب هووووووت ال ةوووووو المووووووااد ثالوووووو حا وووووول مبوووووودي ث ا وووووول موووووو بوووووو ن ح ووووووا ال اااوووووو المث لوووووودف ووووووص المالووووووي مي ووووووت الثالوووووو ي ف وووووو ت فلوووووو ا ووووووت حعوووووو ال م وووووداا الثيب ووووود الوووووذل عووووويا المالوووووي الةووووو اام اص ان اله امووووو الةووووو ب ت ثهثمووووود بووووود اه يووووو ل وووووت ثلوووووا النمووووو ذ الةووووو اام اص مووووون ح وووووث ا وووووت الاوووووبه ال ووووو المةوووووي ب ووووو ت فلووووو بانووووو م الحوووووال المثبوووووم [2,1] ص مي ت فنث المالي الة اام اص ( ذلوووووووع ب ةوووووووثهم مالوووووووح 0781-0781هووووووو د اةوووووووث داا المالوووووووح فلووووووو ال وووووووان الث ةوووووووم لوووووووا ) ح ووووث ا نوووو يوووو لووووا مالووووح نةوووو ت موووون يل وووو ف ، وووو بةوووو ت ووووص مي وووو فنثوووو حد وووود الاهووووا 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 33 ثوووواف اةووووث دامه ي وووو النوووو ث ،ال وووون ووووا اةووووثبدل برل وووو ف النوووو ي ن الثووووص ثاوووو ن يا ووووا قوووو ف مث نووووت موووووون 0598الثالوووووو ي يا ووووووا ن وووووو ف اةووووووثما ث وووووو ا هووووووذل المالووووووح فلوووووو ين ثووووووا عوووووون ثه وووووو ا موووووون p.v.c ب لص ن اي اا د ( الثا ل ن (terylene [3] م اد ي اى من ة اام ا ت ال م يص ماا هت لبهض الدااة الة ب ت الثص ثن ل المالح ةوووث دا مالوووح ف ،0587 ووو ا ،james & eggerstedtم ثوووبه مووون hempamanالب حوووث لثالوووووو ي ال وووووو اا الةوووووو نت المنبه ووووووت موووووون موووووون موووووو دف ةوووووو اام ا ت مةوووووو م ت ذا ح ووووووا حب بووووووص اب ووووووا نةووووووب ح وووووث ينوووووث ، ووووو ثحةووووو ن يدا هووووو ي ذلوووووع مووووون 0580المنلوووووص العووووون ت الثوووووص ا نووووو ثهمووووو منوووووذ ووووو ا ( يوووو لووووا قنوووو ا مةوووو م ت sic-20( يل )grade 20مالووووح موووون ا اب وووود الةوووو ي ا ن ذل ثوووودا ) [4]( mm 10مع )ة( 40𝜇mذا ق ا مة مت ) ceramicن اةووووث داا ا الووووو ت الةووووو اام ا ت المةووووو م ت ف ،0578 ووووو ا ،م م وووووت مووووون البووووو ح ن وووود porous membrance ثه ووووووص ا وووووو ف ي يوووووو نوووووود عوووووو اله وووووودا ن موووووون يوووووو ال وووووو اا ووووووص بوووووووووو الم بثوووووووووت zirconia ت الااا ن ووووووووو دا ووووووووو الحووووووووواااف اله ل وووووووووت هنووووووووود اةوووووووووث داا يالووووووووو yttria الملوووووووبهت بر اةووووووو د الةووووووو ا ا cerium oxide رنهووووووو ث عووووووو اله ووووووودا ن ي ووووووو مووووووون ( الثووووووص يووووووو الووووووااا موووووون ن ذ ثهوووووو الممثوووووو اف ليه ووووووودا ن pt,niا الوووووو ت المهدن ووووووت المعوووووونهت موووووون ) ثعوووووووبي مي وووووووت عووووووو اله ووووووودا ن لع بوووووووذ h2 o2الووووووودا ا ليث ووووووو موووووووم بإةوووووووثهداده لانهووووووو ثمثووووووو ا [5]عهبت ا ا ا ف ووووووو ا عووووووون ت المالوووووووح ،0551 ووووووو ا ،hoogovens industrial ceramicsمااوووووووا الةووووو اام ا ت مووووون ووووون الدااةوووووت الثوووووص قووووو ا بهووووو م م وووووت مووووون البووووو ح ن مووووون ا ووووو حووووو بهوووووض الملووووو ا ت الثووووص ثث يووووا ثوووو ا وووو او مه نووووت ووووص المالووووح المثهي ووووت بهمي ووووت الثالوووو ي ووووص دا وووو الحوووواااف اله ل وووو الثها وووووووووووووت ،corrosion الثصاوووووووووووو ،wear نوووووووووووود اةووووووووووووثهم له بوووووووووووودا الحوووووووووووواااف اله ل ووووووووووووت اوووووووووووو لبي erosion [6]ب ا ثم د ي الم اد الدا يت بعن ثه ووووص الدااةووووت الثووووص ثن لوووو ث وووو ا ث ن ووووت فنثوووو ،0558 وووو ا ، liu et.alل وووو ووووا ن الب حووووث ceramicالوووووووو ت الةوووووووو اام ا ت ثووووووووا فنثوووووووو يالوووووووو ت ةوووووووو اام ا ت ل ووووووووت الا وووووووو ف ووووووووص الثالوووووووو ي ا ultrafilration membrance ( 60ذا ق ووووووا مةوووووو مت nm ما نووووووت موووووون يوووووو اال م نوووووو ) al2o3 الااا ن ووووو zro2 ث ن وووووت ث ي ووووو ووووو ا بإةوووووث داام ووووو ف فل هووووو مووووو اد ااب وووووت د ووووودف ثعووووونم ح وووووث ي بثووووو الدااةوووووت نووووود اةوووووث داا بهوووووض ا ووووو ،co – firing ا وووووت بإةوووووث دااالثيب ووووود ب وووووو ت ، ب وووووو يوووووو وووووو او الما نووووووت اليد نووووووت اليا ووووووتفاله وووووو ت ماوووووون لهوووووو ين ثه ووووووص ثوووووور اا 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 37 فلوووووو ا وووووو دف ق بي ووووووت اابووووووثن بوووووو ن ب وووووو ا الوووووو ت ليموووووو اد الااب ووووووت ثوووووور ا اب ووووووا يوووووو ةوووووومع ب وووووو ا ث ووووووال يوووووو ث ووووووا الث ا ووووووم الح مووووووص ليمةوووووو مت بووووووذلع ثحاموووووو ن بن ذ ووووووت ا الوووووو ت الووووووذل بوووووود ال ووووووك [7]ال ب المثا نت powderمووووم م م ووووت موووون البوووو ح ن ووووص المههوووود البح ووووص لمث ل ا وووو المةوووو ح ل s.g.barayقوووو ا metallurgy research institute، بدااةووووووت المالووووووح الةوووووو اام ا ت ث ن ووووووت ،0557 وووووو ا ceramic open cell foamsالةووو اام ا ت ال ي وووت الااووو ا مووون ووون ث ووو ا فنث هووو ذلوووع ةووووووو اف اب ووووووواف يووووووو ق وووووووا المةووووووو مت موووووووم ، الن ذ وووووووت ، وووووووثا الحعووووووو يووووووو ا ووووووو دف ل وووووووت ب لمةووووووو م ت [8]عنبت اب اف ان ض ص الا ت وووووص ،ل اللوووواا الثووووص ث وووووثو بثن ووووت م وووو ،5119 يوووو وووو ا ي وووووص ،aquasanaا اةوووو ن يلوووواات ق موووو ث وووووو ا بهووووووض ينوووووو اع المالووووووح الةوووووو اام ا ت الثووووووص لهوووووو ال ووووووداف يوووووو ثالوووووو ي الباثا وووووو بدااةووووووت حد ووووووت [9]ا ال ت الاق ت اله الل الدق ت الم دف ص م ل اللاا مووون مووو اد مثووو اف محي ووو هوووص ) ، قووو ا بثح ووو ا مالوووح ةووو اام ا ت5117ن ووو اه وووا ه وووا، وووص ووو ا ( لاووووص ثه ووووص م وووو ا ةووووث دامه soda-lime glass مةووووح ل الا وووو ا ث وووو دل اموووو الةوووو ي ا ابووووودا يا وووووو ليمالوووووح ا ووووواى ذلوووووع بهووووود ثووووو ا م م وووووت مووووون ال ووووو او ال ا وووووت الم ا ن ا وووووت، [10] الثص ثب ن عنح ثه لي اض الذل ينث من ي يا با ف دف ( experimental workالجزء العملي ) مووون مووو اد ي ل ووووت محي وووت ثوووا اثبوووو ع اابهوووت مااحووو موووو ceramic filters نثووو المالوووح الةووو اام ا ت ا ة ت ثه ت الم اد ا ل ت -ي ا ثه ت ثلا النم ذ ن بان م الحال ل ف اا ال ح ع اا ثب اا النامت -اابه (0اقا )مب ن ب للا هذل المااح م حت ب لم ال 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 37 raw materialsالمـواد األوليـة ثا اةث داا نث م اد ي ل ت ص هذل الدااةت انث مالي ة اام اص هص ا ثص : sio )2السيليكا ) -1 umاةووووث دم اموووو الةوووو ي ا المنثلوووواف ووووص من ووووت العووووحاا ال اب ووووت ب لثحد وووود موووون م يووووم اا يا وووومت urdhuma هوووو ثحيوووو ن ا م وووو لمها ووووت نةووووبت الةوووو ي ا اللوووو ا ا الم وووو دف ووووا ب اةوووو ت ي ا وووو ي ح ووووث ثووووا ف وووواا هووووذا volumetric methodب ا ووووت chemical analysisالثحي وووو الا م وووو ص ال حوووووو وووووص م ثبووووواا اللووووواات اله موووووت ليمةوووووي ال لووووو ص الثهووووود ن مووووون ا ووووو مها وووووت نةوووووا الما نووووو (0اقا) ب ل د ه م ي ام الا ة ت الل ا ا المثب ت :5o2si 2( al (oh)4الكاؤولين)-2 موووو دف مثووووو اف بلوووووا ل ةووووم وووووص الهووووواال عوووووت ووووص العوووووحاا ال اب وووووت ان الاوووو ك ل ن المةوووووث دا هووووو مووووون volumetricد يووووووت ال وووووود الثوووووو لص بوووووو ن الثحي وووووو الا م وووووو ص لياوووووو ك ل ن الووووووذل ا ووووووال ب ا ووووووت method ت اله موووووت ليمةوووووي ال لووووو ص الثهووووود ن مووووون ا ووووو مها وووووت نةوووووا الما نووووو وووووص م ثبووووواا اللووووواا (5 ام ه م ي ب ل د اقا ) الا ة ت الل ا ا المثب ت (: 3cacoكاربونات الكالسيوم)-3 99.6) موووو دف ا اب نوووو الا لةوووو ا المةووووث دمت ووووص البحووووث هووووص موووو دف م ثبا ووووت ن ووووت بي وووو ن ثهوووو (art 2069 / usa)( حةا م اع لاات % مرحلة تهيئة المواد األولية: ثث وووووووومن هووووووووذل الماحيووووووووت ثه ووووووووت الموووووووو اد ا ل ووووووووت الدا يووووووووت ووووووووص ثاا ووووووووا المالووووووووي الةوووووووو اام اص )الةوووووووو ي ا الا ك ل ن ا اب ن الا لة ا( ص م يص ث ي لا ت ثح ا ثيع الم اد ثه ثه اة المة ح ل -0 ةح ل ال ابيت ي ع الم -5 ان مي وووووت ثحد ووووود ح وووووا ال ةووووو م ثمووووو لمووووو دف الةووووو ي ا المةوووووث دمت وووووص البحوووووث ح وووووث ثوووووا ا ث ووووو ا ووووودف ب ةووووووث داا من وووووو )اااب وووووو ( م ثي ووووووت sievingح وووووو ا حب ب ووووووت م ثي ووووووت ذلووووووع ب ةووووووث داا ا ووووووت ال ابيووووووت 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 78 اقووووا مب نووووت ووووص ال وووود هووووص ووووص هووووذل الدااةووووت المةووووث دما ووووص هووووذل ال ثحوووو يموووو ح ووووا ال ةوووو م (3) مرحلة تهيئة وتشكيل النماذج: ص هذل الماحيت هن لع نث ا ا اثب ه من ا ف النم ذ اللا النه ص ي المة ح ل -0 ابه ي ثلا النم ذ -5 الث ف -3 مي ت ي المة ح ل ث ةا فل قةم ن binderثح ا ي الم دف الااب ت -0 الم دف الااب ت مم الة ي ا ي -5 ثوووووا ثح ووووو ا المووووو دف الااب وووووت مووووون يووووو الاووووو ك ل ن موووووم ا اب نووووو الا لةووووو ا حةوووووا النةوووووا المب نوووووت يدنووووو ل ذلع ب ةث داا ال ن الاهاب ص لمدف مه ة 65% clay + 35 % caco3 binder وووووص البحوووووث ح وووووث ثووووووا ا ث ووووو ا ووووونث نةووووووا بهووووود ف وووووداد المووووو دف الااب ووووووت ح وووووا ال ي ووووو المةووووووث دمت م ووووت موووون الةوووو ي ا لووووث ي مووووم الموووو دف الااب ووووت ليحعوووو يوووو ال ي ووووت النه ووووت الثووووص ثاوووو ن الموووو دف الثووووص ذلووووووع ل ووووواض منحهووووووت الث ووووواا الثووووووص ث وووووواي يووووو يوووووو المةوووووو م ا ةووووو نث منهوووووو المالوووووي الةوووووو اام اص لوووووو ا فلوووووو نةووووووا ال يوووووو ( 4اقووووووا ) وووووود الاله ها ووووووا م مووووووت اان وووووو مووووووم ث ووووووا نةووووووبت الاموووووو المةووووث دمت ان م وووووم النةووووا الم ثاحوووووت ثموووو يووووو الح وووو ا ال ةووووو م ال مةووووت الم ثووووو اف مةووووب امووووو ان مي ت ال ي حعي ب اة ت ال ن الاهاب ص لمدف مه ة :compacting the samplesكبـس النماذج احوووود موووون ا يوووو ذلووووع ب ةووووث داا الماووووبه ال وووود ل قبوووو ثووووا اةووووث داا ا ووووت الاووووبه لووووبا ال وووو ف ب ث وووو ل { يمووووو ان اله نوووووت p.v.a% مووووون 5( }بنةوووووبت p.v.aالاوووووبه ووووو ف مووووو دف البووووو لص نووووو الاحووووو لص ) لوووووا ال لوووووا يبهووووو دل م وووووداا الحمووووو المةوووووث دا هثمووووود يووووو ال عووووو ت الموووووااد دااةوووووثه امووووو م وووووي 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 78 لوووووا مووووون ال الوووووا ال اذ وووووت امووووو ثههوووووا وووووص ال ووووود وووووص ال ووووود الثووووو لص ثوووووا اةوووووثهم لووووواي ن مووووون ي (9اقا ) ryingdالث ف بهوووود ان ثر ووووذ النموووو ذ اللووووا النهوووو ص ثاوووو ن ال وووو ف الث ل ووووت هووووص الث ووووف ليه نوووو موووون ا وووو فاالووووت الموووو º 110 الا بوووت لاوووص ثاثةوووا النمووو ذ بهوووض العووونبت ثوووا الث وووف ب وووان الث وووف بدا وووت حووواااف ) c ة ت 52( لمدف firing :الحـرق ال ووووو ف ا ووووواف نثووووو المالوووووي الةووووو اام اص هوووووص الحوووووال ي الثيب ووووود ح وووووث ثمووووو مي وووووت الثيب ووووود لينمووووو ذ المهوووووودف ةوووووو ب بوووووو نث دا وووووو حااا ووووووت م ثي ووووووت ل م ووووووم نةووووووا ال يوووووو المووووووذا اف ي وووووونل ل م ووووووم الح وووووو ا ( ذلووووووووع ب ةووووووووث داا ووووووووان الحووووووووال 1200ºcالحب ب ووووووووت الم ثوووووووو اف ا نوووووووو دا ووووووووت الحوووووووواااف الم ثوووووووو اف هووووووووص ) دا ووووت لاوووو دق ووووت ( ثوووواف ماوووو ث نوووود ثيووووع دا ووووت الحوووواااف )ةوووو ت 5الاهابوووو ص اوووو ن مهوووود الثةوووو ن ) حووووواااف ال ا وووووت بووووون ه مهووووود احووووودف ( وووووا ثااووووو اله نووووو فلووووو ان ثبووووواد دا ووووو ال وووووان ثعووووو فلووووو دا وووووت الثة ن : apparent porosityقياس المسامية الظاهرية الةوووووووو اام اص الميبوووووووود ههووووووووا مةوووووووو م ت مث وووووووواف الدا ووووووووت ح ووووووووث ان المةوووووووو م ت هووووووووص ق وووووووو ه لاوووووووو المنووووووووث المةووووو م الم ووووو دف ب لمووووو دف ةووووو ا ا نووووو م ث حوووووت ي م ي وووووت ب ووووو لوووووذلع ثههوووووا ن ووووو ن مووووون المةووووو م ت الح ووووووت اله ها ووووووت المةوووووو م ت اله ها ووووووت ماوووووون الثهب ووووووا نهوووووو برنهوووووو نةووووووبت ح ووووووا المةوووووو م الم ث حووووووت ا الايص لي ةا فل الح امووو ان astm standard (c373-88) وووص حةووو ا المةووو م ت اله ها وووت المووو ثوووا ااةوووثن د فلووو [ 00ا نث ت ا ق مت هص مهد ل نث نم ذ حةا ال ا الث ل ت ] ةوووووو ت( ووووووا ثثوووووواع 24( لموووووودف )150ºcث ووووووف النموووووو ذ ووووووص ووووووان الث ووووووف نوووووود دا ووووووت حوووووواااف ) -0 لدا ت حاااف ال ا ت بهده ب ال ان ال ف لينم ذ لثباد فل ان ثع ةوووووو ت( مووووووم 5 وووووه النموووووو ذ ووووووص د ال ا وووووو ص م ووووو ا امووووووا ب لموووووو الم ووووووا اي ووووو لموووووودف ) -5 ووووووم ن ا نهوووووو دا موووووو م موووووو اف ب لموووووو ثهوووووو ض الموووووو المثب ووووووا بهووووووده ثااوووووو النموووووو ذ م موووووو اف ب لموووووو لينم ذ ب ةث داا لبات ماثب ت ب لم اان ة ت( ب ال ان المهيل ب لم 24لمدف ) 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 78 مب لووووواف بهووووود ث ب ووووو ا اان المهي وووووت ث وووووف ةووووو ق النمووووو ذ مووووون ق ووووواا المووووو اله ل وووووت بهووووو ب اةووووو ت -3 ق هت قم ا من ال ن ا حةا ال ان الملبم ب لم (1اقا) بهد ف اا م م ال ا ي نل حةب النةبت الم ت ليمة م ت من المه دلت -2 حة ا المة م ت اله ها ت porosity %=(( m-d) / (m-s)) *100 …………………… (8) ح ث ان m( ال ان الملبم g ) d( ال ان ال ف g ) s( ال ان المهيل g ) compressive strength :مقاومة االنضغاط قياس ثاوووووووو ن م مووووووووت اان وووووووو ل ووووووووت لمههووووووووا الموووووووو اد الةوووووووو اام ا ت لووووووووذا هووووووووص ثث يووووووووا ا م ا ن ا ووووووووت ي ه دا ل ا ووووووت وووووواا ال حووووووو الووووووناا بح ووووووث اوووووو ن الحموووووو المةووووووي حموووووون مح ا وووووو يوووووو النموووووو ذ قوووووود ا ثاووووو ن النمووووو ذ المةوووووث دمت مةوووووث يت ي ماهبوووووت ي اةووووو ان ت اللوووووا نووووود ف ووووواا هوووووذا ال حوووووو ل ةووووو ( ذلوووووع حةوووووا h = 2dالةوووو اام ا ت لوووووثا ان اوووو ن ووووو النمووووو ذ ووووهف ق وووووال يل ان ) ، ووووص الهوووو دف اوووو ن ةوووو ح الماووووبه ووووص astm standard (c773-8الم اعوووو الم بثووووت ووووص ) الم انووووت مثوووو اا ن ااووووا ذلووووع ث ووووم ل حثوووو ن عوووو يث ن موووون ال لووووا وووو ل النموووو ذ ثحثووووا ا وووو ووووم ن ا ة ق مث اا ت ند اا ثب ( حةوووووب م موووووت اان ووووو ليمووووو دف ب ةوووووثهم م انوووووت 3-9 نووووود ثه وووووت النمووووو ذ امووووو مبووووو ن ب للوووووا ) اا ثبوووو اا الهوووو ا المب نووووت ةوووو ب اوووواا ال حووووو لوووو نث نموووو ذ ح ووووث ان اوووو نث ووووت ا ق مووووت هووووص مهوووود (2اقووووا ) اموووو وووص المه دلوووت astm standard (c773-88)لووو نث نمووو ذ ذلوووع ب اةووووثن د فلووو [05] compressive strength = pc / a …………………… (8) 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 77 ح ث ان compressive strength( م مت اان mpa ) pc( الحم المةي حث الاةا n ) a( مة حت م م النم ذ mm ) (discussion results andالنتائج والمناقشة ) بهووووو مي ن مهمووووو ن همووووو مي وووووت الثيب ووووود ال ووووو ا ال نووووو ا المثا نوووووت ثثووووور ا عووووو ت المةووووو م ت اله ها وووووت -0 ثووووووور ا نةوووووووبت الامووووووو المث ووووووواف يووووووو هوووووووذل ال عووووووو ت اذ (2دا ووووووو ال ةوووووووا الةووووووو اام اص بووووووو ن اللوووووووا ) ان ا وووووو دف (8 اقووووووا ) اموووووو مبوووووو ن ب ل وووووود ننحووووووه ان المةوووووو م ت اله ها ووووووت ثوووووواداد با وووووو دف نةووووووبت الاموووووو نةوووووبت الامووووو ثه وووووص ووووو ا اا وووووا انهووووو ثه وووووص ثاا بووووو ه اي ووووو مثيوووووع اااووووو بووووو ن الحب بووووو هوووووذا مووووو ةوووووا ا ووووو دف النةوووووبت الم وووووت ليمةووووو م ت با ووووو دف النةوووووبت الم وووووت ليامووووو م مووووو امووووو ان ووووو د ا اب نووووو ( محووووووااا اوووووو ا 900ºcلةوووووو ا نوووووود )الا لةوووووو ا ا وووووود المةوووووو م ت ذلووووووع بةووووووبا ث ااووووووا الوووووو ي اةوووووو د الا (co2 الوووووووووذل ا ووووووووود مووووووووون نةوووووووووبت المةووووووووو م ب ل ةوووووووووا الوووووووووذل ث ووووووووول موووووووووم مووووووووو ث عووووووووو ال وووووووووا بووووووووو ح ن ) [14 13 ا ن ] ( ههوووووا ثووووور ا ث وووووا ح وووووا ةووووو م الامووووو يووووو المةووووو م ت اله ها وووووت ثبووووو ن وووووا ين 3يمووووو اللوووووا ) يل ان نوووود ا وووو دف الح ووووا الحب بووووص ث وووو ي يوووو ق مووووت ليمةوووو م ت اله ها ووووت نوووود اقوووو ح ووووا ل ةوووو م الاموووو ين الا وووووو دف ووووووص ح وووووو ا حب بوووووو الاموووووو (8 اموووووو مبوووووو ن ب ل وووووود اقووووووا ) اوووووو موووووون المةوووووو م ت اله ها ووووووت بووووور اان احووووودف ةووووو ف ثه وووووص ووووودد مووووون الحب بووووو اقووووو وووووص حووووودف الح ا)ح وووووا النمووووو ذ ( مووووون الحب بووووو ابوووووووا ح مهووووووو ايمووووووو ابوووووووا ح وووووووا الن موووووووت اوووووووذلع ان ال ووووووو ا المثا نوووووووت بووووووو ن الحب بووووووو ووووووو ووووووودده الحب بوووو بووووود هنووووو ان الا ووووو دف وووووص ووووودد ال ووووو ا المثا نوووووت بةوووووبا عووووو ا الحب بووووو قووووود ا ووووو ام وووووت موووون ال وووو ا يابووووا موووون ثيووووع ال وووو ا ب وووو د حب بوووو لوووونت بهووووذا ااد المةوووو م ت ب وووو د حب بوووو الاموووو الن مت ث ايم ابا هذل الحب ب م مووووووت اان ووووو ثه وووووص ثعوووووو ا ووووون م موووووت الموووووو دف الهوووووا ف الثوووووص ماوووووون ان دااةوووووت م موووووت -5 ان ثةووووث دا هوووو م مووووت الموووو دف ثحوووودده الهد وووود موووون اله اموووو م وووو ا ووووت الموووو دف دا ووووت حوووواااف الحووووال الث ووووو ن الا م وووووت الثوووووص ثحعووووو بووووو ن الما نووووو اوووووذلع اا هووووو دا الثوووووص ثههوووووا وووووص ال ةوووووا ا نووووو ا ذلع من ا دف ص الح ا الثبا د م ع ح 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 77 ( بووووو ن ين الا ووووو دف وووووص نةوووووبت امووووو الةووووو ي ا وووووص النمووووو ذ ث يووووو مووووون الم موووووت ين هوووووذا 4اللوووووا ) اموووو الث ووووا وووواثب بلووووا اة ةووووص مووووم ث ووووا المةوووو م ت اذ ثوووواداد المةوووو م ت مووووم ا وووو دف نةووووبت اموووو الةوووو ي ا ( ح وووووث انوووووا لووووو ا 5نووووت اللوووووا ) اموووو ثووووور ا ح وووووا ةووووو م الامووووو ب (8هوووو مبووووو ن وووووص ال ووووود اقوووووا) الةووووبا هوووو د الوووو ان وووو ض المةوووو م ت ا نهوووو ث وووو با وووو دف الوووو ا وووو دف الم مووووت ايموووو ااد ح ووووا ال ةوووو م ح ا ال ة م لذلع ن د ين الم مت ثاداد ثب conclusionsاالستنتاجات ث ل ا من ن النث الثص ثا الحع ي ه مان ال ا ا ااةثنث ال ان ووووو ض قووووو ا م موووووت اان ووووو ليمالوووووي الةووووو اام اص ااث ووووو ع المةووووو م ت اله ها وووووت موووووم ا ووووو دف نةوووووبت -0 الام ض المة م ت اله ها ت مم ا دف الح ا الحب بص ليام ا دف ق ا م مت اان ان -5 referencesالمصادر 1harper a. ch., hand book of ceramics, glasses, and diamonds, mc grawhill publiediun, pp.686, 2001. 2meyers a. m., chawla k. k., mechanical behavior of materials, prentice hall, new jersey, pp25-30, 1998 3singer f., singer s.s., industrial ceramics, chapman and hall ltd. published, 1963, p.1455. 4 james z., eggerstedt p., ceram. bull., vol. 70, no.1, 2000 5lede j., interim. chem. eng., vol.26, no.4, 1998. 6hoogovens, industrial ceramics, world ceramic and refractories, incorporating euroclay and refractories, vol.1, no.1, 2007 7-www.freepatentsonline.com http://www.freepatentsonline.com/ 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 77 liu j., rieß w., münch ch, ziegler g., development of a co-firing technique for the production processes of ceramic, 1996. 8-www.mi.infn.it/~landnet/doc/chemical-mod. baray s. g., development of high ceramic in pmri pp, 1998. 9-www.waterwaterweb.com./waterfilters.htm/. aquasana, water filter guide line, 2005. ن اه ا ه ا " ثعن م مالح ة اام ا ا من ا الع دا ا ا مم الام المحيص" اة لت -01 5117م ةث ا مهت ب ب 11astm annual book of standards, c373-1988, pp.104-11 12astm annual book of standards, c7731988, pp.245-247 13van vlack h. l., elements of materials science and engineering, 4th edition, 1980 14-kingery w.d., bowen h.k., uhlmann d.r., introduction to ceramics, 2nd edition, new york, p1032, 1976. بواسطة الطريقة الحجمية نتائج التحليل الكيميائي للسيليكا :(1رقم ) جدول sio2 al2o3 k2o l.o.i total يا اة د % 98.34 0.31 0.17 1.18 100 http://www.mi.infn.it/~landnet/doc/chemical-mod http://www.waterwaterweb.com./waterfilters.htm/ 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 77 بواسطة الطريقة الحجمية كاؤوليننتائج التحليل الكيميائي لل :2)رقم ) جدول sio2 al2o3 fe2o3 tio2 cao mgo na2o k2o l.o.i total يا اة د % 46.66 34.41 0.83 1.2 0.96 0.34 0.3 0.34 12.94 100 في تركيب المرشح السيراميكي حجم جسيمات الرمل المختارة: 3)جدول رقم) size opening(µm) mesh 150 100 125 120 100 140 75 200 50 270 نسب الخلطات الداخلة في تشكيل المرشح السيراميكي(: 4جدول رقم) السيليكا ت )%( المادة الرابطة )%( sio2حجم الجسيمات (µm) عـــــــــــــــــــــدد الخلطات مجمـــــــو النماذج a 40 60 150,125,100,75,50 5 25 b 50 50 150,125,100,75,50 5 25 c 60 40 150,125,100,75,50 5 25 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 73 في طريقة الكبس شبة الجاف القوالب الفوالذية و أوزان العينات و الضغوط المستخدمة(: 5جدول رقم) باتجاه واحد من االعلى يبه د ال لا ال ع ت (mm) يبه د النم ذ (mm) ان لا النم ذ اله نت (g) الحمووووووووووووووووووووو المةث دا (ton) a المةوووووووووووو م ا اله ها ت do = 50 din = 30 h = 70 d = 30 t =2 d t 6 2 b عووووووووووووووووو ت اان do = 20 din = 10 h = 50 d = 10 h =20 h dr 3 0.225 (: نتائج تغير المساميه الظاهريه مع تغير نسبة الرمل وحجمه الحبيبي6جدول رقم ) grainsize(µm) 40% sand 50%sand 60%sand 50 31.228 36.344 41.328 75 30.102 32.991 37.881 100 29.887 32.366 36.112 125 28.495 31.128 33.563 150 28.016 30.655 31.192 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 77 (: نتائج تغير مقاومة االنضغاط مع تغير نسبة الرمل وحجمه الحبيبي7جدول رقم ) ثه ت الم اد ا ل ت الثيب د )الحال( المة م ت اله ها ت م مت اان ق ه grainsize(µm) 40% sand 50%sand 60%sand 50 6.166 5.899 4.858 75 7.782 6.765 5.567 100 8.672 7.653 7.217 125 9.966 8.122 8.534 150 11.831 9.788 9.366 فصل المسحوق الغربلة أو المساحيق غسل الخلط وتحديد النسب كبس وتشكيل النماذج التجفيف يوضح مراحل العمل :( 1)رقم شكل 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 77 sand % تأثير نسبة الرمل على المسامية الظاهرية : (2)شكل رقم µm ) particles size of sand ( بي للرمل(: يوضح تغير المسامية مع تغير الحجم الحبي3شكلرقم ) 0 5 10 15 20 25 30 35 40 45 0 20 40 60 80 100 120 140 160 sio2(40%) sio2(50%) sio2(60%) 0 20 40 60 80 100 120 140 160 180 200 30 50 60 partical size(50µm partical size(75µm) partical size(100µm) partical size(125µm) partical size(150µm) ap pa re nt p or os ity ap pa re nt p or os ity 4102 3العدد 7المجلد مجلة القادسية للعلوم الهندسية 78 sand% (: يوضح تغير مقاومة األنضغاط مع تغير نسبة الرمل4شكل رقم ) sand (µm) of particles size (: يوضح تغير مقاومة االنضغاط مع تغير الحجم الحبيبي للرمل5شكل رقم ) 0 2 4 6 8 10 12 14 40 50 60 partical size(50µm) partical size(75µm) partical size(100µm) partical size(125µm) partical size(150µm) 0 2 4 6 8 10 12 14 0 20 40 60 80 100 120 140 160 sio2(40%) sio2(50%) sio2(60%) co m pr as siv e st re ng th µ pa co m pr as siv e st re ng th µ pa st re ng th al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 352 effect of oil products on compressive strength of reactive powder concrete asst. lec. sana taha abdul-hussain civil engineering department, college of engineering, al-mustansiriya university, sanaalsalami@gmail.com abstruct the aim of this study is to investigate the effect of two of oil products (kerosene and fuel oil which is locally called as black oil) on compressive strength of reactive powder concrete (rpc). rpc was prepared using cement, silica fume, fine sand, steel fibers and superplasticizer to cast and test 63 specimens of cubes with various steel fibers ratios of 0%, 1% and 2% at different exposure times in oil products (0, 30, 90 and 180) days. in general the results showed that rpc has good resistance to the effect of kerosene and fuel oil. a slight decrease in compressive strength occurred as the time of exposure to the oil products increases. the rpc specimens of 2% steel fibers content had the lower decrease in compressive strength as a result of the denser microstructure. the decreasing ratio of rpc compressive strength exposed to fuel oil (1.33%) was lower than that of kerosene (2.91%). this may be attributed to the lower viscosity of kerosene than fuel oil. key words: reactive powder concrete, oil products, kerosene, black oil, compressive strength. لى مقاومة األنضغاط لخرسانة المساحيق الفعالةتأثيرالمشتقات النفطية ع م.م سنا طه عبد الحسين الهندسة المدنيةالجامعة المستنصرية،كلية الهندسة،قسم الخالصة المشتقات النفطية (النفط االبيض و نفط الوقود المعروف محليا ه الدراسة هو التحري عن تأثير اثنين منالهدف من هذ الرمل الناعم، تم تحضير خرسانة المساحيق الفعالة من السمنت، .النفط األسود) على مقاومة األنضغاط لخرسانة المساحيق الفعالةب الحديد نموذج من المكعبات بأستخدام نسب مختلفة من ألياف 63لصب و فحص والملدن المتفوق ألياف الحديدأبخرة السليكا, النتائج اظهرت ان بشكل عام) يوم. 180و 90، 30، 0%) عند اوقات تعرض مختلفة في المشتقات النفطية (2% و%1، 0( لنفط االبيض و النفط االسود. مقاومة االنضغاط انخفضت قليال بزيادة زمن ت مقاومة جيدة لتأثيراذاخرسانة المساحيق الفعالة لهيكلها االكثر كثافة. هي االقل انخفاضا في المقاومة كنتيجة % الياف حديد2التعرض للمشتقات النفطية. الخلطة التي تحتوي على رضة قل من تلك المتع%) أ1.33(احيق الفعالة المتعرضة لنفط الوقود ان نسبة االنخفاض في مقاومة االنضغاط لخرسانة المس . للزوجة االقل للنفط االبيض مقارنة مع نفط الوقودلان ذلك قد يعود .%)2.91( للنفط االبيض .، مقاومة االنضغاطالنفط االسود ،النفط االبيضالمشتقات النفطية، ،خرسانة المساحيق الفعالةالكلمات المرشدة: al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 353 introduction in the mid 1990`s, one of the astonishing developments in the field of concrete technology was made by introduction of ultra-high performance fiber reinforced (uhp-frc) by richard and cheyrezy (1994) which is more commonly known as ultra-high performance reactive powder concrete (rpc) [behzad et al. (2012)]. reactive powder concrete (rpc) is coarse aggregate-free concrete, which has limited applications so far recorded in the construction industry [tam et al. (2012)]. oil has become one of the most vital energy resources from the beginning of the previous century for its unique economic and operative characteristics. this has enabled it to exceed the other available power resources, and its importance has increased rapidly with its wide spread use and the discovery of huge oil reserves in different parts of the world [ra’ed (2002)]. durable concrete has the ability to withstand the effects of environmental conditions to which it will be subjected, such as weathering, chemical attack, and abrasion. the migration of water, petroleum products, and other liquids through properly designed, placed, consolidated, and uncracked concrete is minute. concrete is impermeable for all intents and purposes. for example, with a permeability coefficient of (3×10-14m/s) for concrete with a water cement ratio of 0.45, the loss of water through the wall of (1900 m3) tank would be less than (4 litters) per year. the thickness of the concrete and the hydrostatic head of the liquid in tanks of normal proportions do not significantly affect the rate of migration through the concrete [close and jorgensen (1991)]. structures for storage or transportation of oil have for years been constructed of steel, but as a result of the critical storage of steel plate and problems of serviceability and safety during the second world war, reinforced or prestressed concrete tanks were used to store many different liquids, such as: crude oil, bitumen, heavy fuel oil, light fuel oil, gas oil, lamp kerosene, power kerosene etc. [abdul hussein (2005)] storage of liquid petroleum products may be done in above ground or underground steel or concrete tanks or in underground salt domes, mined caverns or abandoned mines. underground tanks are most common for military bases, gasoline stations and wholesale bulk storage terminals [cholakov (2003)]. [al-zaidi (2001)] studied the influence of oil products (gas oil and kerosene) on the physical properties of concrete and he revealed that specimens cured in gas oil and kerosene showed higher compressive strength for all ages compared with their water counterparts. the effect of state of concrete (wet or dry) before exposure to oil products doesn’t produce significant effect on the compressive strength. many researchers [lea (1970), aci (1968), pearson and smith (1919)] have reported that mineral oil has no effect on the quality of concrete. the damage of the oils depends on their viscosity; the higher viscosity of the oil, concrete is the less dangerous [rashed (1998)]. therefore viscosity of oil is a very important property for oil store tanks [spamer (1994), [biczock (1964) and hernibrock (1994)]. researches conducted by [williamson (1982), bergstrom (1975) and jonston (1982)] showed that the increase in compressive strength was ranging from negligible, in most cases, to 15% for 150mm×300mm cylinders containing different types and contents of fibers. [al-hamadani (1997)] studied the mechanical properties of concrete exposed to gas oil. he used different types of admixture such as high rang water reducing agent (hrwr), microsilica agent (ms), lime stone dust (lsd) and he found that the compressive strength of dried concrete specimens resoaked in gas oil was increased by (2.6%, 4.1%, 1.7%, and 2.4%) after 180 days soaking for hrwr, ms and lsd mix. the compressive strength of the admixture al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 354 concrete was higher than that of concrete without admixture for the same curing and exposure conditions. the increase in strength of admixture concrete was attributed to the pozzolanic activity in case of using micro silica, which produced additional gel, and due to reduced w/c ratio in case of hrwr. for lsd concrete the reduction in air content and filler increase in density were responsible for the observed increase in strength. the following advantages and disadvantages of concrete for oil storage can be listed [abdulhussain (2005)]. • advantages: 1. much lower cost compared with steel plates. 2. the availability of its raw materials throughout the world. 3. a significant durability towards different types of environment. 4. good resistance to fire, explosions and impact. 5. its adaptability for different types. 6. relative low maintenance cost. 7. its suitability for underground, and under-sea storage tank. • disadvantages: 1. the unknown behavior of concrete in direct contact with oil products. 2. penetration of the lighter fraction of oil products through the tanks. 3. concrete undergoes volume changes. these may be as shrinkage or thermal movements. thus cracking may be unavoidable. 4. possible bond weakening in oil saturated concrete tanks. 5. the impossibility of moving concrete tanks to different locations. 6. possibility of cracks due to differential settlement. the present work is focused on compressive strength of rpc after exposure to oil products because of the most common of all tests on hardened concrete is the compressive strength test, partly because it is an easy test to perform, and partly because many, though not all, of the desirable characteristics of concrete are qualitatively related to its strength; but mainly because of the intrinsic importance of the compressive strength of concrete in structural design [neville (2005)]. experemental program the experimental program was conducted to study the behavior of concrete mixes of rpc that was in direct content with oil products. the purpose of this investigation is to identify the means of achieving impermeable concrete that can be used for the construction of oil storage tanks or oil pipelines. there are many other industrial situations where concrete may come into direct contact with different garage floor and oil drilling rings… etc. the specimens were exposed to oil products for various times after water curing of 28 days and compared with reference mix specimens which was cured in water without exposure to oil products. two types of oil products have been used (kerosene and fuel oil). the exposure time to the oil products were (0, 30, 90 and 180) days after the initial curing. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 355 materials cement ordinary portland cement (type i tasluja-bazian) which is produced in iraq by the united cement company (ucc) was used in all test specimens. the chemical analysis and physical test results of the cement are given in (tables 1 & 2), respectively. they conform to the [iraqi specification no. 5/1984]. silicafume silica fume is a highly reactive material that is used in relatively small amounts to enhance the properties of concrete. the chemical composition and properties of silica fume used in this work are given in (table 3). steel fibers the characteristics of steel fibers used in the experimental program are given in (table 4). (figure 1) shows a sample of the used steel fibers. fine aggregate fine aggregate from al-najaf al-ashraf region has been used. it is yellowish brown colored sand with rounded shaped particles. the grading of this sand is shown in (table 5). superplasticizer a superplasticizer type which is known commercially as (sikavisco crete-pc 20) was used in this work. sikaviscocrete-pc 20 is a third generation superplasticizer for concrete and mortar. (table 6) indicates the technical description of aqueous solution of the superplasticizer used. it is free from chlorides and complies with [astm c494/c494m-1999a]. oil products (table 7) show the properties of kerosene and fuel oil respectively which are used in this investigation. they were brought from the local market and stored in plastic containers to avoid any losses. water tap water has been used for concrete mixing and curing of specimens. mix proportions in most basic form, reactive powder concrete contains high content of portland cement as main cementitious materials beside silica fume as a second supplementary cementitious component. the superplasticizer has been used in an appropriate ratio to give flowable concrete. in addition steel al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 356 fibers are also added to enhance its properties. many mix proportions were tried in this study to get maximum compressive strength. the variable used in the rpc mix was the volume ratio of steel fibers (three volume ratios were considered 0%, 1% and 2%). the mix proportions of rpcs̓ are shown in (table 8). mixing procedures mixing procedure proposed by [wille et al (2011)] was used in this research to obtain rpc in a simpler way without any accelerated curing regimes. pan mixer of 0.056 m3 capacity was used to prepare the concrete. sand and silica fume were first mixed for 4 minutes, then cement was added and the dry component (cement, sand and silica fume) were mixed for 5 minutes. superplastcizer was added to the water and stirred, then the blended liquid was added to the dry mix during the mixer rotation and the mixing process continues for 3 minutes. finely, steel fibers were all added by hand within 2 minutes. the total mixing time was about 14 minutes. specimen's preparation and casting procdure specimen's molds (50 mm cubes) were cleaned thoroughly, tightened well and the internal surfaces were oiled with thin car engine oil to prevent the hardened concrete adhesion with molds. once the concrete mixing was done, the molds were filled with rpc. a vibrating table was used for consolidation of rpc into the molds. after being molded, all the specimens were cured under polyethylene sheets for about 24 hr in a laboratory environment. curing after 24 hours of casting, the specimens were stripped from molds and placed in water containers in the laboratory to be cured at room temperature. heat curing at elevated temperature was not used in this research in order to gain an advantage of producing rpc of exceptional mechanical properties using conventional curing method without any additional provisions. after 28 days of water curing, the specimens were soaked in kerosene or fuel oil in plastic containers for different exposure times (30, 90 and 180 days) until test date. reference specimens (o day exposure time) where tested immediately after the end of water curing. test results three cubes of (50mm×50mm×50mm) for each mix were tested to determine the compressive strength and an average value is obtained according to [astm c109/c109 (2002)]. compressive strength test was performed by using universal testing machine (ele) of 2000 kn capacity in the constructional materials laboratory of engineering college of al-mustansyiria university. results are given in (table 9) and presented in (figures 2 & 15). (figures 2 & 3) show the relationship between compressive strength and different exposure times of kerosene and fuel oil. generally, it is shown from these figures that a slight decrease in compressive strength occurred as the time of exposure increases for the specimens exposed to kerosene and fuel oil. it is also shown that compressive strength of rpc increases with the increase in steel fibers ratio. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 357 (figures 4 & 5) show the relationship between compressive strength and steel fibers ratio of various exposure times of kerosene and fuel oil respectively. it is shown from these figures that the compressive strength increases with the increase of steel fibers ratio. at the ratio of 2% steel fibers the decrease in compressive strength after exposure time 180 days is slight compared with the mixes of 0% and 1% steel fibers content for both kerosene and fuel oil exposure. (figures 6 to 8) show the relationship between compressive strength and steel fibers ratios at exposure time (30, 90 and 180) days, respectively. it is shown from these figures that rpc exhibits good resistance to kerosene and fuel oil exposure especially the mixes with 2% steel fibers. as mentioned before. these best results obtained from rpc with 2% steel fibers may be attributed to its more dense microstructure compared to rpc with lower steel fibers ratios. (figures 9 to 11) show the relationship between compressive strength and exposure time for mixes of (0%, 1% and 2% steel fibers) respectively. these figures show that the compressive strength of specimens exposed to fuel oil is slightly higher than that of specimens exposed to kerosene at the same exposure time and steel fibers ratio. this may be attributed to the lower viscosity of kerosene than of fuel oil (see table 7), which enable kerosene to penetrate through concrete easier than fuel oil. (figures 12 & 13) show the decreasing ratio in compressive strength of rpc exposed to kerosene and fuel oil respectively with the increase in exposure time. generally, low decrease in compressive strength of rpc exposed to kerosene and fuel oil was observed. it is shown in these figures that the decreasing ratio in compressive strength is reduced with addition of 1% steel fibers as presented in (table 9). this reduction is greatly enhanced when 2% steel fibers used. for example, the addition of 1% steel fibers reduces the decreasing ratio in compressive strength from 10.14% to 9.46% for rpc exposed to kerosene for 180 days. the addition of 2% steel fibers drops this ratio to 2.91%. similar trends for other exposure times are shown in (figures 12 & 13) and can be read from the results listed in (table 9). these results makes steel fibers ratio of 2% to be the more effective ratio to enhance the permeability of rpc through the enhancement in rpc microstructure in addition to the main role of steel fibers in increasing ductility and tensile strength of rpc. however, lower decreasing ratios were recorded for rpc exposure to fuel oil (only 1.33 % after 180 days of exposure for rpc with 2% steel fibers) compared to those of rpc exposure to kerosene. this again can be attributed to the lower viscosity of kerosene. (figures 12 & 13) also show that the decreasing ratio in compressive strength increasing with the increase in exposure times for both kerosene and fuel oil. this is expected because longer exposure time allows more penetration of oil products. however, decreasing ratios (after 180 days of exposure) are ranged from 10.14% for rpc with 0% steel fibers exposed to kerosene to only 1.33% for rpc with 2% steel fibers ratio exposed to fuel oil. lower ratios are recorded for exposure times of 30 and 90 days (table 9).the above discussion indicates the good permeability and resistance of rpc to the effects of oil products. (figures 14 & 15) show the increasing ratio of compressive strength of rpc exposed to kerosene and fuel oil respectively with the increase in steel fibers ratio. this increasing ratio is generally ranged from 14.38% to 21.4% where steel fibers ratio increases from 0% to 2%. conclusions based on the experimental results in this research, the following conclusions can be drawn: 1. it is possible to produce reactive powder concrete with compressive strength of 114 mpa using normal water curing at room temperature without using heat curing. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 358 2. for the rpc specimens exposed to kerosene and fuel oil, a slight decrease in compressive strength occurred as the time of exposure increases. the decreasing ratio is ranged from only 0.08% for rpc of 2% steel fibers exposed to fuel oil for 30 days to 10.14% for rpc of 0% steel fibers exposed to kerosene for 180 days. 3. the compressive strength of rpc increases with the increase of steel fibers ratio for different exposure times and oil products. the increasing ratio is generally ranged from 14.38% to 21.41% when steel fibers ratio increases from 0% to 2%. 4. rpc with 2% steel fibers exhibits better resistance to kerosene and fuel oil exposure (strength decreases after 180 days of exposure by 1.33% for fuel oil and 2.91% for kerosene), than that of rpc with 0% (strength decreases after 180 days of exposure by 9.42% for fuel oil and 10.14% for kerosene) and 1% (strength decreases after 180 days of exposure by 8.42% for fuel oil and 9.46% for kerosene). these better results may be attributed to the denser microstructure (lower permeability) of rpc with 2% steel fibers compared to rpc with lower steel fibers ratios. 5. the compressive strength of rpc specimens exposed to fuel oil is slightly higher than that of specimens exposed to kerosene at the same exposure time and steel fibers ratio. this may be attributed to the lower viscosity of kerosene than that of fuel oil, which enables kerosene to penetrate through concrete easier than fuel oil. references abdul hussain f.k., 2005, '' influence of crude oil and kerosene on the properties of fiber reinforced concrete'', m.sc. thesis, university of technology baghdad. aci "manual of concrete practice" part3, usa, 1968. al-hamadani, z.k. , 1997, “improvement of the performance of concrete against oil products” m.sc. thesis, university of technology baghdad. al-zaidi, m.d., 2001, “influence of oil products on the physical and electrical properties of concrete”, ms.c thesis, university of technology, 116 pp. astm c109/c109m-02,"standard test methoqd for compressive strength of hydraulic cement mortars (using 2-in. or [50-mm] cube specimens)". astm c494/c494m-1999a,"standared specification for chemical admixtures for concrete". astm c1420-2003,"standard specification for use of silica fume as a mineral admixture in hydraulic cement concrete''. behzad n., raizal s.m.r., mohad. s.j., 2012, ''a review on ultra high performance 'ductile' concrete (uhpdc) technology'', international journal of civil and structural engineering, volume 2, no 3, ssn 0976 4399. bergstrom, s.g., 1975, “anordic research project on fiber reinforced cement based materials”., fiber reinforced cement and concrete rilem sympos sium, construction press ltd. lancaster, london, vol – 2, pp.7. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 359 biczock, i., 1964, "concrete corrosion and concrete protection", pub. house of the hungarian academy of science, budapest, pp. 324-329. cholakov g.st., 2003, ''control of pollution in the petroleum industry'', pollution control technologies-vol.iii-control of pollution in the petroleum industry, http://www.eolss.net/eolsssampleallchapter.aspx. close s.r. and jorgensen l.f., 1991, ''prestressed concrete tanks for hazardous liquids'', point of view, concrete international, october, pp47-51. hernibrock, f. b., 1994, "the effectiveness of various treatment and coating for concrete in reducing penetration of kerosene'', aci. journal, proc. v.41, p.13-20. iraqi specification, no. 5/1984, (السمنت والسيطرة النوعيةلمركزي للتقييس االجهاز وزارة التخطيط, .البورتالندي) iraqi specification, no. 45/1984, الجهاز المركزي للتقييسوزارة التخطيط, والسيطرة النوعية (ركام تعمل في الخرسانة والبناء) المصادر الطبيعية المس jonston c.d., 1982, ”steel fiber reinforced concrete a review of mechanical properties”, fiber reinforced concrete, american concrete institute publishing, sp 44, , pp. 127-143. lea f.m., 1970, "the chemistry of cement and concrete", london, edward arnold (pub.) ltd., pp. 659-665. neville a.m., 2005, "properties of concrete", england, fourth edition, p581. pearson j.c., and smith, g.a, 1919, "test of concrete tanks for oil storage'', aci journal, proc. v.15. ra’ed k.h.a., 2002, “behavior of high performance concrete in direct contact with an oil products”, m.sc. thesis, university of technology baghdad. rashed l., 1998, "behavior of fiber reinforced concrete exposed to oil products", m.sc. thesis, university of technology, baghdad. spamer m. a., 1994, "navy installation of protective linings for prestressed concrete tanks containing liquid fuels'', aci journal, proc. vol.40 april, pp417-428. tam, c.m., tam, v.w.y. and ng, k.m., 2012, ''assessing drying shrinkage and water permeability of reactive powder concrete produced in hong kong'', construction and building materials 26,pp. 79-89. wille, k., naaman, a. e., and montesinos, g. j., 2011, "ultra-high performance concrete with compressive strength exceeding 150mpa (22ksi): a simpler way", aci materials journal, januaryfebruary, title no.108-m06, pp.46-54. http://www.eolss.net/eolss-sampleallchapter.aspx http://www.eolss.net/eolss-sampleallchapter.aspx al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 360 williamson g.r, 1982, “the effect of steel fiber reinforced concrete”, sp 44, american concrete institute, detroit, , pp. 195-207. table (1): chemical composition of cement* compound composition chemica l composi tion percent by weight [iraqi specification no. 5/1984] lime cao 61.19 silica sio2 21.44 alumina al2o3 4.51 iron oxide fe2o3 3.68 magnesia mgo 2.31 maximum 5 sulfate so3 2.7 maximum 2.8 loss on ignition l.o.i 2.39 maximum 4.0 insoluble residue i.r 1.18 maximum 1.5 lime saturation factor l.s.f 0.87 0.66-1.02 tricalcium aluminates c3a 6.06 tricalcium silicate c3s 42.85 dicalcium silicate c2s 29.4 tricalcium alumina ferrite c4af 11.18 *all tests were made at the national center for construction laboratories and research. table (2): physical composition of cement* physical properties 0btest results 1biraqi specification no. 5/1984 fineness using blain air permeability apparatus(cm2/gm) 4050 minimum 2300 setting time using vicat’s instruments initial(min.) final(hr) 135 3:25 minimum 45 maximum 10 compressive strength for cement paste cube at: 3days(mpa) 7days(mpa) 28days(mpa) 24.4 32.3 47.2 minimum 15 minimum 23 *all tests were made at the national center for construction laboratories and research. al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 361 table (3): composition and properties of silica fume* *according to the manufacturer editors. table (4): characteristics of steel fiber used* *according to the manufacturer editors table (5): grading of fine sand* sieve size (mm) cumulative passing % [iraqi specification no.45/1984] zone 4 9.5 100 100 4.75 100 100-95 2.36 100 95-100 1.18 100 90-100 0.600 88 80-100 0.300 20 15-50 0.150 5 0-15 *the test has been performed in the structural material laboratory of engineering college of almustansyiria university. composition (%) silica fume astm c1240-03 sio2 98.87 minimum 85% al2o3 0.01 fe2o3 0.01 cao 0.23 mgo 0.01 k2o 0.08 na2o 0.00 blaine fineness (m2/kg) 200000 type of steel hooked relative density 7860 kg/m3 yield strength 1130 mpa modulus of elasticity 200 000 mpa strain at proportion limit 5650*10-6 poisson's ratio 0.28 average length (l) 30 mm nominal diameter (d) 0.375 aspect ratio(l/d) 80 al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 362 table (6): technical description of the used superplasticizer* *according to the manufacturer editors. table (7): properties of oil product used* oil inspection data kerosene results fuel oil (black oil) results moisture content, % by volume 0.05 0.1 0.05 0.1 sulfer content, % by weight 0.2 0.3 4 5 h2s concentration ppm 2 – 3 2 3 specific gravity (gm/cm3) at: 20 cº 0.78-0.80 0.95 0.985 25 cº = = 30 cº = = 35 cº = = 40 cº = = 80 cº = = viscosity (centipoises) 1.36 at (20 cº) 135 at (60 cº) 1.25 at (25 cº) 80 at (70 cº) 1.16 at (30 cº) 63 at (75 cº) 1.07 at (35 cº) 51 at (80 cº) 1.00 at (40 cº) 42 at (85 cº) 34 at (90 cº) 29 at (95 cº) 24 at (100 cº) *oil analyses were made by the laboratory department/ al-dura refinery. main action concrete superplasticizer appearance/colures light brownish liquid chemical base modified polycarboxylates based polymer density 1.09 kg/l, at 20 °c ph 7 chloride ion content% free effect on setting non-retarding al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 363 table (8): mix proportions of reactive powder concrete mixes mixture description rpc 0% rpc 1% rpc 2% portland cement (c) (kg/m3) 900 900 900 silica fume (sf) (kg/m3) 225 225 225 *silica fume % 25 25 25 fine sand (fs) (kg/m3) 900 900 900 steel fibers ( kg/m3) 0 78 156 **steel fiber % (by volume) 0 1 2 superplasticizer (kg/m3) 56.25 56.25 56.25 ***superplasticiz er % 5.5 5.5 5.5 water (w) (kg/m3) 180 180 180 w/c 0.2 0.2 0.2 w/(c+sf) 0.16 0.16 0.16 *percent of cement weight, **percent of mix volume, ***percent of binder (cement + silica fume) weight. table (9): results of compressive strength mix description s teel f ibers ratio ( %) oil prod ucts exp osure time (da y) compressi ve strength (mpa) decreasing rate in compressive strength as time of exposure increased for the same product and steel fibers ratio (%) increasing rate in compressive strength as the steel fibers ratio increased for the same product exposure time (%) rpc-0% 0 97.6 a1-0% 0 kerosene 30 93.6 4.09 a3-0% 0 kerosene 90 90.69 7.07 a6-0% 0 kerosene 180 87.7 10.14 b1-0% 0 fuel oil 30 94.1 3.58 b3-0% 0 fuel oil 90 91.7 6.04 al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 364 b6-0% 0 fuel oil 180 88.4 9.42 rpc-1% 1 105.6 7.57 a1-1% 1 kerosene 30 101.6 3.78 7.87 a3-1% 1 kerosene 90 98.9 6.34 8.3 a6-1% 1 kerosene 180 95.6 9.46 8.26 b1-1% 1 fuel oil 30 102.8 2.65 8.46 b3-1% 1 fuel oil 90 99.5 5.77 7.83 b6-1% 1 fuel oil 180 96.7 8.42 8.58 rpc-2% 2 114 14.38 a1-2% 2 kerosene 30 113.8 0.17 17.75 a3-2% 2 kerosene 90 112.2 1.57 19.17 a6-2% 2 kerosene 180 110.68 2.91 20.76 b1-2% 2 fuel oil 30 113.9 0.08 17.38 b3-2% 2 fuel oil 90 113 0.87 18.84 b6-2% 2 fuel oil 180 112.48 1.33 21.4 figure (1): steel fibers used in rpc al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 365 . 0 20 40 60 80 100 120 0 50 100 150 200 co m pr es si ve s tr en gt h (m pa ) exposure time (days) figure (2): relationship between compressive strength and different times of kerosen exposure rpc-0% steel fibe rpc-1% steel fibe rpc-2% steel fibe 0 20 40 60 80 100 120 0 50 100 150 2 co m pr es si ve s tr en gt h (m pa ) exposure time (days) figure (3): relationship between compressive strength and different times of fuel oil exposure rpc-0% steel fib rpc-1% steel fib rpc-2% steel fib 0 20 40 60 80 100 120 0% 1% 2% co m pr es si ve s tr en gt h (m pa ) steel fibers (%) figure (4): relationship between compressive strength and steel fibers ratios of kerosen exposure exposure time 0 day exposure time 30 days exposure time 90 days exposure time 180 days 0 20 40 60 80 100 120 0% 1% 2%c om pr es si ve s tr en gt h (m pa ) steel fibers (%) figure (5): relationship between compressive strength and steel fibers ratios of fuel oil exposure at exposure time 0 day at exposure time 30 days at exposure time 90 days at exposure time 180 days al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 366 0 20 40 60 80 100 120 0% 1% 2% co m pr es si ve s tr en gt h (m pa ) steel fibers (%) figure (6): relationship between compressive strength and steel fibers ratios at (exposure time 30 days) compared with mixes not exposed to oil products kerosen exposure fuel oil exposure without exposure 0 20 40 60 80 100 120 0% 1% 2%co m pr es si ve s tr en gt h (m pa ) steel fibers (%) figure (7): relationship between compressive strength and steel fibers ratios at (exposure time 90 days) compared with mixes not exposed to oil products kerosen exposure fuel oil exposure without exposure 0 20 40 60 80 100 120 0% 1% 2% co m pr es si ve s tr en gt h (m pa ) steel fibers (%) figure (8): relationship between compressive strength and steel fibers ratios at (exposure time 180 days) compared with mixes not exposed to oil products kerosen exposure fuel oil exposure without exposure al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 367 86 88 90 92 94 96 98 100 0 100 200 co m pr es si ve s tr en gt h (m pa ) exposure time (days) figure (9): relationship between compressive strength and exposure time for mixes of (0% steel fibers) kerosen exposure 94 96 98 100 102 104 106 108 0 100 200co m pr es si ve s tr en gt h (m pa ) exposure time (days) figure (10): relationship between compressive strength and exposure time for mixes of (1% steel fibers) kerosen exposure 110.5 111 111.5 112 112.5 113 113.5 114 114.5 0 100 200 co m pr es si ve s tr en gt h (m pa ) exposure time (days) figure (11): relationship between compressive strength and exposure time for mixes of (2% steel fibers) kerosen exposure fuel oil exposure al-qadisiya journal for engineering sciences vol. 6 no. 4 year 2013 368 0 2 4 6 8 10 12 30 90 180 d ec re as in g ra ti o (% ) exposure time (days) figure (12): decreasing ratio of compressive strength of rpc exposed to kerosen mixes with 0% steel fibers mixes with 1% steel fibers mixes with 2% steel fibers 0 2 4 6 8 10 30 90 180 d ec re as in g ra ti o (% ) exposure time (days) figure (13): decreasing ratio of compressive strength of rpc exposedto fuel oil mixes with 0% steel fibers mixes with 1% steel fibers mixes with 2% steel fibers 0 5 10 15 20 25 0 30 90 180 in cr ea si ng r at io (% ) exposure time (days) figure (15): increasing ratio of compressive strength of rpc exposed to fuel oil mixes with 1% steel fibers mixes with 2% steel fibers 0 5 10 15 20 25 0 30 90 180 in cr ea si ng r at io (% ) exposure time (days) figure (14): increasing ratio of compressive strength of rpc exposed to kerosen mixes with 1% steel… iraqi specification no. 5/1984 test results template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 274 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. optimal capacitor placement to reduce active power losses and harmonic in unbalance distribution system inaam ibrahim ali university of technology, al sinaeuh street, baghdad, iraq. email: 30037@uotechnology.edu.iq received on 27 september 2016 accepted on 9 august 2017 abstract: this paper proposed an algorithm to find the best location of shunt capacitor and size to reduce the total active power loss and harmonics consideration after assuming electric arc furnace (eaf) in the unbalanced radial distribution network. demonstrated the results by using practical software (cymdist) as a tool, to determine power flow and find the best capacitors size and location that decrease power loss and improve voltage profile. the total harmonic voltage distortion at system does not exceed the maximum allowable total harmonic voltage distortion level (thvd%) compared with ieee-standard 519-1992. to attain the goal of this algorithm, these algorithms are tested in 25-buses unbalanced radial distribution system and an actual part of baghdad city distribution network that is content 66-bus for al_jihad_feeder_5 11 kv network are depicted for the implementation of this analysis. keywords: unbalanced distribution system, capacitor placement, cymdist software, active power loss, harmonic voltage distortion level (thvd %). introduction the electric distribution network is becoming large and complex causing the increasing of the load then produce losses and result in increased ratings of distribution components [1]. the power loss is significantly high in distribution networks because of lower voltage levels and higher currents, when compared to transmission systems. studies have indicated that as much as 13% of total power generated is consumed as i 2 r losses in the distribution sector.this non-negligible amount of losses directly impacts financially and reduces the overall efficiency of the power system. these losses cannot be eliminated but can be reduced [2]. one of the most effective and useful methods in reducing the power losses of distribution networks is utilization of optimal capacitor placement. by using shunt capacitors, the reactive power needed for loads is pro-vided so that besides the reduction of losses the voltage profile of nodes is also improved. there are, of course, numerous difficulties in optimal placement of capacitors in the purpose of reducing losses. these problems include: i. non-clarity of the behavior of feeders’ loads, particularly domestic loads, ii. complexity of distribution net-works, iii. variety of the type of network loads. reactive power compensation plays an important role in the planning of an electrical system. the amount of compensation provided is very much linked to the placement of capacitors in the distribution mailto:30037@uotechnology.edu.iq al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 275 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. system, which is essentially determination of the location, size, number and type of capacitors to be placed in the system. the power system harmonic analysis is to determine the impact of harmonic producing loads on a power system. addition load in the network such as electric arc furnace (eaf) is an un-balanced, nonlinear and time varying load, which can cause many problems to a distribution system and other users. the voltage-current characteristic of the arc is non-linear, that may cause harmonic currents. these currents, when circulating by the electric net can produce harmonic voltages, which can affect to other users. in reference [4], the electrical model of an electric arc furnace integrates with the thermal model for its performance evaluation. the effect of different arc furnace models on voltage disturbance is reviewed in [5, 6]. furthermore, in three phases unbalanced distribution network, real coded genetic algorithm [7] and, index vector method are applied to find capacitors best location and size in unbalanced redial distribution system [8]. limited work has been devoted to the literature to find the best optimal capacitor placement in unbalanced distribution system, and limited attention is given to this problem in the presence of voltage and current harmonics. the contribution of this work presents harmonic and loss minimization in unbalanced distribution system by finding the best location and sizing of shunt capacitors. 1. problem formulation 1.1 objective function the proposed objective function which has to be minimized can be expressed as follows: ………………..(1) where; pl: total power losses (kw); are the fundamental and harmonic components for total power losses (kw) respectively; hmin and hmax: is minimum and highest order of harmonics. 1.2 problem in addition to the minimization of the objective function, the following constraints should be satisfied: i. the power factor constraint: p.f. of the network is not permit less than 0.8. ii. thd constraint: total harmonic voltage distortion (thvd %) for the system must be less than or equal to 5%, as refer to by the ieee standard 519-1992[9]. iii. capacitor constraint: the reactive power injected (kvar)) should not be exceed the total reactive power demand in the network or system source. .................(2) where; 𝑄𝑐: is the total reactive power injection; 𝑄: total reactive power demand before injection. the injections (kvar) based on the standard capacitor sizes by abb (according to ieee and iec standard) in kvar are: 50,100, 150, 300, 450, 600, 750, 900, 1200, etc. [1]. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 276 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 1.3 harmonic load flow analysis studies for unbalanced distribution system due to the un-balanced line sections and loads in distribution networks, three phase models should be used in harmonic analysis. for example, the impedance matrix of a three phase line section [z abc ] can be expressed as [10]: .....................(3) where : , , are self impedances in phase a, b, and c respectively. is mutual impedance between phases a and b. is mutual impedance between phases b and c. is mutual impedance between phases c and a. the results of distortion level and voltage wave forms are useful to verify compliance with harmonic limits. harmonic power flow can be presented mathematically as [11]: .......................(4) .................... (5) where: [z h ], [y h ]: are the network impedance and admittance matrix of a distribution system for the h th order harmonic matrix respectively. [i h ]: is the harmonic current injection of network. [v h ]: is the harmonic voltage; and (h) is the harmonic order. the voltage thds after the harmonic propagation of each order has been solved can be represented as: . thds (%) = ................(6) where: thds (%): total harmonic distortion in the system. : the normal voltage on the busbar to the harmonic frequency. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 277 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. no no 2. the proposed algorithm the proposed algorithm for optimal capacitor placement in a radial distribution feeder is summarized by the flowchart shown in (figure 1). figure 1. flowchart of capacitor placement for the search of best suitable location and sizing in un-balanced radial distribution feeder using cymdist program. start input data (r, x, and loads) run the unbalanced load flow analysis for the original feeder put qc at the far end bus from the substation using cymdist program run load flow analysis thd s-voltage 5 % pf > 0.8 add new qc using cymdist program re-move qc , and put prior values of qc run the load flow analysis constraints satisfied? put qc at the next bus stop yes yes al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 278 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. simulation and results in this paper two cases have been studied, investigate the effect of the capacitor placement in a proper location with harmonics consideration after assuming electric arc furnace (eaf) in the unbalanced distribution network. the first case studied was to verify the applicability of cymdist program on a standard distribution system whose harmonics analysis results are well documented in the literature based on standard ieee519-1992. the standard system considered was the ieee 25bus un-balanced radial distribution network. finally, the proposed method was implemented using a practical system from the distribution network in baghdad city. 3.1 case 1: test system to attain the proposed algorithm, these algorithm is applied on 25-bus un balanced radial distribution network test system and schematic of this test system are shown in (figure 2) with electric arc furnace (eaf), and its data are provided from [11]. figure 2. single line diagram of 25 bus un-balanced radial distribution network with electric arc furnace (eaf) [11] this work uses an ieee-519-1992 standard (ieee recommended practices and requirements for harmonic control in electrical power systems) to comparison with test system which the value of thd-voltage (total harmonic voltage distortion thd %) the recommended voltage distortion limits must be lower than 5%. in 25-bus test system, the electric arc furnace (eaf) adding in the system. after using load flow analysis kirchhoff's current law (kcl) and kirchhoff's voltage law (kvl), the computed total active power losses is 241.16 kw and the measured maximum thd-voltage was 10.06 % phase a and b respectively and 10.05 phase c. to reduce the active power losses and thd, the optimal capacitor placement is achieved using al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 279 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the proposed method using standard rating of single-phase capacitors by abb (according to ieee and iec standard) are shown in following table 1. table 1. standard single-phase capacitor ratings. the injected reactive power (kvar) is 3150 (kvar), and the total active power loss reduced to 157.16 kw, whereas the maximum total harmonic voltage distortion are reduced to 0.36 % phase a,0.21% phase b and 0.14% phase c respectively, lower than uncompensated. the program result is shown in table 2. figure 3. single line diagram of 25 bus un-balanced radial distribution network after adding capacitor placement with electric arc furnace (eaf). table 2. the comparison of 25bus test system with ieee-519 standard limits. xc (kvar) 50 100 150 200 300 400 500 600 discretion total harmonic distortion voltage thd % voltage p.u. total active power losses (kw) a b c a b c 241.16 without capacitor placement 10.06 10.06 10.05 0.921 0.921 0.921 with capacitor placement 0.36 0.21 0.14 0.983 0.982 0.981 157.16 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 280 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figures (4 to 7) show the wave form of the total harmonic distortion voltage and harmonics order of voltage before and after capacitor placement. figure 4. the wave form of voltage befor compensation. figure 5. harmonic order of voltage befor compensation. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 281 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 6. the wave form of voltage after compensation. figure 7. harmonic order of voltage after compensation. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 282 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3.1.1 voltage profile for the ieee 25-bus test system un-balanced radial distribution network with three-phase harmonic analysis. figures 8 and 9 show the downstream voltage profile with respect to distance for the 25bus test system un-balanced radial distribution network with electric arc furnace (eaf), before and after capacitor placement. figure 8. voltage profile for the 25-bus test system un-balanced radial distribution network before compensation. figure 9. voltage profile for the 25-bus test system un-balanced radial distribution network after compensation. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 283 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3.2 case 2: al_ jihad substation to implement the proposed method on an actual distribution network in baghdad city the chosen network was al_ jihad distribution network. the capacity of al_ jihad (33/11 kv) substation is (2*31.5 mva) delta-delta connection, which is fed by two 33kv feeders from al-jazayr and albayaa expansion substations (132/33/11 kv). there are fourteen (11 kv) feeders outgoing from albayaa substation serving a large area of mixed residential, commercial, industrial, and trading loads. the proposed analyses are implemented using the cymdist 4.5 (rev.6) software and before starting, some assumptions are made in this work: i. unbalance voltage drop iterative method is used, the maximum number of iterations is 40 for load flow and the voltage magnitude convergence error is set to be 0.01%. ii. the (rms) value of bus voltages will be kept inside acceptable tolerance limits (±5 %) after applying both optimal capacitor placement to verify objective function for the average peak demand and the study effect of total harmonic voltage distortion must be lower than 5% , within ieee-519-1992 standard limits. iii. load factor for the al_ jihad distribution network is equal to 100%. 3.2.1 al_ jihad distribution network this network is a part of the distribution network in baghdad city which is rated at 11 kv, base mva =100, and frequency of 50 hz with (386) line sections, (375) buses, and 12 tie switches. the schematic diagram of al_ jihad system is shown in figure (10). the load for al_ jihad feeders is mixed, approximately 90% residential, 4% industrial and 6% commercial. only one feeder is considered in this work. the modeling of al_ jihad distribution network is based on the actual positions of each bus. this coordination’s are taken from iraqi ministry of electricity depending on the global positioning system (gps). the coordinates are entered to the cymdist module as x and y coordinates for the buses to build the model and specify the actual length of the network sections. unbalance loads in feeder_5 for al_jihad distribution network are distributed in all sections for each phase depending on the current and power factor values at the sending end of feeder_5 and the secondary (11/0.4 kv) transformer (deltagrounded wye) connection. figure 10. initial configuration of al_ jihad distribution network with the secondary transformers (11/0.4 kv). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 284 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. after applying the load flow for the initial configuration to al_ jihad distribution network, it can be noted that this feeder_5 operates in an abnormal condition with 21 sections at under voltage and 7 sections are over load as shown in figure (11a). tables (3, 4 and 5) illustrate the optimal of capacitor placement and sizing, also the load summary before and after reactive power compensation. figure (11-b) show the allocation of the capacitors at the receiving buses on feeder_5. figure 11. the abnormal and normal conditions before and after optimal capacitor allocations for feeder_5 in al_ jihad distribution network. table 3. optimal location and size of capacitor placement for al_ jihad distribution network at peak load conditions (100% loading). al_ jihad feeder_5 : p.f corrected to 0.99 node id cap. kv (l-l) total capacitor (kvar) for all phase loss reduction (kw) 10 11 600 15.8 17 11 600 7.7 22 11 900 6.2 33 11 450 10.8 37 11 900 2.9 total 3450 43.4 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 285 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 4. load summary before and after kvar compensation of feeder_5 for the al_ jihad distribution network at peak load. al_ jihad feeder_5 system load total adjusted shunt capacitor + total conductor capacitances system losses system supply before kvar compensation kw 3755.5 -- 106.4 4661.9 kvar 2918.19 0+3.39 3629.35 kva 4756.01 --5908.09 p.f. 0.8 --78.91 ampere/phase a 313.7 ------b 319.2 c 310.8 after kvar compensation kw 3755.5 -- 64.95 4620.45 kvar 2918.19 3343.84+3.56 247.87 kva 4756.01 --4627.1 p.f. 0.8 --0.992 ampere/phase a 245.4 ------b 246 c 238.5 table 5. summary of result of feeder_5 for al_ jihad distribution network. al_ jihad feeder_5 voltage before kvar compensation for each phase voltage after kvar compensation for each phase a b c a b c maximum voltage (p.u.) 1 1 1 1 1 1 minimum voltage (p.u.) 0.944 0.943 0.944 0.975 0.974 0.975 the values of the harmonic contents are listed in table (6) below for the effect electric arc furnace on feeder_5 for al_ jihad distribution network and the measured maximum total harmonic voltage distortion (thvd %) on phase a, b and c respectively before and after optimal capacitor placement in a proper location and sizing of feeder_5 in al_ jihad distribution network comparison with ieee-519 standard 5191992 limits. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 286 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 6. result total harmonic voltage distortion (thd %) for al_ jihad feeder_5 distribution network before and after capacitor placement. figures (12 to 15) show the wave form of the total harmonic voltage distortion and harmonics order of voltage for feeder_5 in al_ jihad distribution network before and after capacitor placement. figure 12. the wave form of voltage before compensation discretion total harmonic voltage distortion thd % a b c without capacitor placement 3.09 3.09 3.09 with capacitor placement 0.06 0.06 0.06 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 287 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 13. harmonic order of voltage before compensation. figure 14. the wave form of voltage after compensation. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 288 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 15. harmonic order of voltage after compensation. 3.2.2 voltage profile for al_ jihad feeder_5 distribution network figures 16 and 17 show the downstream voltage profile with respect to distance for feeder_5 in al_ jihad un-balanced radial distribution network with electric arc furnace (eaf), before and after adding capacitor placement. figure 16. voltage profile for al_ jihad feeder_5 before adding capacitor placement. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 289 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 17. voltage profile for al_ jihad feeder_5 after adding capacitor placement. conclusion due to the increasing size and complexity of distribution networks, using the practical software as a tool for the simulation and analysis of such networks become a necessity. the proper location and sizing of the capacitors in redial distribution network resulted; reduction total power losses, improve voltage profile , and reducing total harmonic voltage distortion level. these results were obtained from simulation for; 25 bus test system 1 and 66-bus of feeder_5 al_ jihad network 2 . the simulation results show that the reactive power compensation by using proposed algorithm more reduction for total power losses and total harmonic voltage distortion (thvd %) compared with matlab (a novel approach direct search algorithm) and ieee standard 519-1992 respectively. also, the minimum voltage in the phase (a, b and c), are improved from (0.944, 0.943 and 0.944 p.u) to (0.97, 0.974 and 0.975 p.u respectively) after adding the capacitor placement. references 1. fitriana, s.; dimas, f. u.; ontoseno, p. p.; adi, s., capacitor placement and sizing in distorted distribution systems using simplified direct search algorithm.” journal of clean energy technologies”, vol. 2, no. 4, october 2014. 2. hemasekhar, a.; chevireddy, h., voltage profile improvement by capacitor placement and control in unbalanced distribution systems using differential evolution algorithm,” international journal of advanced research in electrical, electronics and instrumentation engineering”, vol. 3, issue 8, august 2014. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 290 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. masoum, m. a. s.; ladjevardi,; jafarian, m. a.; fuchs ,e. f., optimal placement, replacement and sizing of capacitor banks in distorted distribution networks by genetic algorithms,” ieee trans. power delivery”, vol. 19, no. 4, pp. 1794-1801, oct. 2004. 4. chirattananon, s.; gao ,z., a., model for the performance evaluation of the operation of electric arc furnace,” energy convers mgmi”, vol37, no.2, 1996, pp. 161-166 5. alonso, m.; donsion, m., an improved time domain arc furnace model for harmonic analysis,” ieee trans. on power delivery”, jan2004, vol.19, no. 1, pp. 367-373. 6. rafael c. t. g., identification and modeling of a three phase arc furnace for voltage disturbance simulation, „ieee trans. on power delivery”, oct. 1997, vol.12, no. 4, pp 1812-1817. 7. hooshmand ,r. ; atael, m., real coded genetic algorithm applied to optimal placement of capacitor banks for unbalanced distribution systems with meshed/radial configurations,” international energy journal”, 8 (2007) 51-62. 8. seyed ,a. ; bagherpour, r., a new approach for optimal capacitor placement and sizing in unbalanced distribution systems using hybrid honey bee colony algorithm,” elsevier electrical power and energy systems”, 2013,49:430-448. 9. ieee sm 519-1992(revision of ieee sm 519-1981) (ieee recommended practices and requirements for harmonic control in electrical power systems), recognized as an american national standard (ansi) april 12, 1993. 10. jen-hao,t,; shu-hung l.; rong-ceng l., three-phase harmonic analysis method for unbalanced distribution systems,” journal energies” 2014 issn 1996-1073. 11. subrahmanyam, r..c. j., a novel approach for optimal capacitor location and sizing in unbalanced radial distribution network for loss minimization,” copyright © jes 2009 on-line: journal.esrgroups.org/jes”. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 41 evaluation of oil and grease contamination of euphrates river in al kufa river station during 20102011 dr. hussein abdulmuttaleb ali khan lecturer at university of kufa/ eng. college received 16 september 2013 accepted 19 january 2014 absract the effects of pollution sources on receiving water quality are diverse and depend on the type and concentration of pollutants. the present study was conducted on al kufa river in al-kufa city in the aim of studying the contamination levels of oil and grease, with some water quality parameters (no3, ph, t.u., cl,) and selected climatic parameters (precipitated dust particles, temperature, dust storm, and rain) were depended. samples of raw water were collected and analyzed from kufa river station during a period of fifteen months, starting from october 2010 to december 2011. the purpose is to assess the level of parameters measured and their effects on the river. statistical analysis used to describe the relations between oil and grease and the other parameters and a regression analysis was performed by "data fit" program version 8.0 software. this study showed that discharging domestic sewage and industrial waste water from adjacent areas, caused oil and grease contamination of levels more than iraqi standard limits in 64 times .the highest values of oil and grease recorded in heavy rainy months impacted by runoff from land, the second highest values of oil and grease occurred in high level of weather temperatures. finally, oil and grease levels, also increased according to precipitated dust particles, and dust storm which will lead to use more amounts of oil and grease due to different activities, followed by discharging of polluted waters to sewers or into river directly. keywords: oil and grease, nitrate, hydrogen ion concentration, turbidity, chloride, precipitated dust particles, regression models. نهر الفرات في بالزيوت والشحومتقييم التلوث (0200-0202للفترة ) في محطة شط الكوفة م.د. حسين عبد المطلب علي خان كلية الهندسة -جامعة الكوفة al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 42 الخالصة يختلف تأثير مصادر الملوثات على المسطحات المائية حسب نوع وتركيز تلك الملوثات. هذه الدراسة اختصت بدراسة مستويات بعض خصائص المناخ ) والتلوث بالنفط والزيوت مع بعض مكونات الماء )النترات، أيون الهيدروجين، العكورة، الكلورايد( تم أخذ عينات ومن ثم تحليلها من مياه نهر الكوفة في مدينة الكوفة.بالغبار، واالمطار( الغبار المتساقط, درجة الحرارة, عواصف الهدف .0200وحتى نهاية كانون األول في العام 0202في العام األولالنهر من محطة الكوفة وبواقع نموذجين شهريا من تشرين وثات على مياه النهر من خالل التحليل االحصائي لمعرفة درجة االرتباط فيما بينها وباستخدام برنامج للمعرفة تأثير تلك الم "data fit" program version 8.0 software . بينت الدراسة بأن تصريف مياه الصرف الصحي وبعض االنشطة مرة أعلى من الحدود المسموح 46تصل الى لزيوتوا الصناعية في المناطق المجاورة تسبب زيادة في مستويات التلوث بالنفط ن أعلى مستويات التلوث بالنفط كانت في أشهر تساقط المطر الذي يتسبب بسحب تلك الملوثات كما وأالمواصفات العراقية. في ها ب وأخيرا فقد بينت الدراسة بأن ارتفاع مستويات .الجو عند ارتفاع درجات حرارةوالى المجاري ومن ثم وصولها الى النهر ، وما ينتج عنها من نشاطات واعمال تؤدي الى زيادة لترابيةا فزيادة تساقط الغبار والعواص اتفترفي التلوث بالنفط والزيوت كان .الى شبكات المجاري أو الى النهر مباشرة تصريفها استعمال المشتقات النفطية ومن ثم ، نمذجة االنحدار.المتساقط الكلورايد، الغبار ,العكورة ، النترات، أيون الهيدروجين،الزيوت والشحوم كلمات رئيسية: 1.introduction water, is used for many purposes associated with human activity. in its natural state it occurs in and on the ground in subsurface and surface reservoirs. the quality and reliability of a water source will vary considerably, both in time and space. this means that characteristics (chemical, physical, and biological) will differ greatly depending upon the location and type of the source. it also means that a given source may vary over the seasons of the year (pfafflin and ziegler, 2006) . water pollution can be defined as the presence in water of enough harmful or objectionable material to damage the water’s quality (pankratz, 2001). water pollutants are categorized as point source or nonpoint source, the former being identified as all dry weather pollutants that enter watercourses through pipes or channels. storm drainage, even though the water may enter watercourses by pipes or channels, it is considered a nonpoint source pollution. other nonpoint source comes from agricultural runoff, construction sites, and other land disturbances (weiner and matthews, 2003). traditionally, in united states, water quality standards are classified as the following nine parameters: dissolved oxygen (do), ph, coliform, temperature, floating solids (oil–grease), settleable solids, turbidity– color, taste–odors, and toxic substances (corbitt, 2004). pollution from petroleum compounds (“oil pollution”) first came to public attention with the torrey canyon disaster in 1967. the huge tanker loaded with crude oil plowed into a reef in the english channel. despite british and french attempts to burn the oil, almost all of it leaked out and fouled french and english beaches. eventually, straw was used to soak up the oil and detergents were applied to disperse the oil (detergents were later found to be harmful to the coastal ecology) (weiner and matthews, 2003). abriola and pinder (1985) formulated a one-dimensional finite difference model which included immiscible organic flow, water flow, and equilibrium inter-phase transfer between the immiscible organic phase, the water phase, and a static gas phase. the results of this simulation were described to demonstrate the numerical algorithms incorporated in the model as cited by (sleep and sykes, 1989). kaluarachchi and parker (1989) presented an isothermal two-dimensional finite element model named mofat-2d for three phase flow and transport by allowing for interphase mass exchange. this model is based on galerkin’s weighted residual approach and an upstream weighting technique to predict simultaneous flow of water and oil in a three fluid phase system with gas assumed constant at atmospheric pressure. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 43 euphrates river has a large importance for iraqi environmental researchers because of the detrimental effect of pollutants resulting from treated and untreated domestic wastewater, treated and untreated industrial wastewater and farming and agricultural pollutants. al-mayahi, 2005 studied the pollution by petroleum in sediments of three stations at shatt al-arab river. samples were collected monthly from october 2003 to september 2004. spectrofluorometic method was used to determine the total petroleum hydrocarbons and using basra crude oil as standard. many ecological parameters also were determined for three selected stations. values: salinity, ph, dissolved oxygen, bod5, total organic carbon (toc), nitrates and phosphates were investigated, and he showed that the measured values fluctuated according time and space of human activities. a large number of populations of iraq reside along the banks of euphrates and tigris rivers so that the utility of such water for bathing and recreation purposes cannot be aesthetically good. the polluted water especially by oil and grease are also difficult to be easily treated and it is found that the treatment plants have to be increased in handling such water. the objective of the study is to evaluate oil and grease contamination of euphrates river at al kufa river station. 2. study area kufa is a city in iraq, about 170 kilometers south of baghdad (capital of iraq), and 10 kilometers northeast of najaf. it is located on the banks of the euphrates river. euphrates river branches after al-kifil town directly about (1km) to two branches (first one is shatt al kufa and another branch named al abbasia river). the main sources of water for this river are rain water, stored water as lake and reservoirs. al kufa station is located on the euphrates river/shatt al-kufa, near the al kufa water treatment plant for surface water monitoring, at coordinates (e044.4075, n32.03941) figure (1). the water level at the station is not stable, in the summer decline is attributed to its lowest level so that the bottom of the river can be seen in some areas near the station, and in winter the water levels are not rising as required, and the center of the river is not covered with water even in winter and the rainy season. the nature of the land surrounding the station is agricultural land, with some residential buildings at a distance (100 m to the south) and farming land on the other side. al kufa river passes through many towns and villages thus it represents the main source for different uses such as: -irrigation: irrigation for large agricultural areas locating on both sides of the river. -water supply systems: water supply for many water treatment plants such as al-najaf and alkufa water treatment plants. -industrial purposes: the main source for all industrial activities in the area. in addition to these main uses, the river receives many pollutants discharged by different sources, including: -careless use of pesticides can contaminate water sources and make the water unsuitable for drinking. wastes of animals and plants from agricultural areas are discharged to the river on both sides. -municipal wastes: municipal wastes are discharged from northern drainage of al kufa (2 km / north) and raw waste water discharged from al jimaah zone at 1 km / north of station. -industrial wastes: many industries discharge wastewater to the river such as soft drink factory and many private industries. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 44 3. model formation data of oil and grease concentrations, some water quality parameters, and climatic conditions factors of the euphrates river (at kufa river station) are being analyzed monthly, and the pollution levels are being determined. in present study the statistical models are described the relations between parameters of water quality. the regression analysis was done by using "data fit" program version 8.0 software . also, two statistical methods were utilized for analyzing data collected from the sampling site: correlation analyses, regression variable (t-ratio and prob(t)), and variance analyses (prob (f)). correlation analyses were performed on the individual water quality parameters to identify relationships between them. variance analysis to determine the overall significance of the regression model accordingly, multiple non-linear regression models in three forms were used for each design requirements to choose which form gives the best fitting of data. the regression models that were proposed and investigated can be seen in table (1). 4. data analysis this research covers the study and analysis the pair of monthly water quality parameters of surface water for euphrates river at al kufa river station, and climatic conditions factors involved. data for euphrates river in al kufa station were collected, from the period extended from october 2010 to december 2011. these data represent the nitrate (no3), hydrogen ion concentration (ph), turbidity unit (t.u.), chloride (cl), precipitated dust particles (pm, g/m 2 ), mean max. temperature (t), dust storm (ds), and monthly rain totals (ra) as independent variables, and oil &grease (o&g) as dependent variable, as shown in table (2). the samples of water parameters were tested in the laboratory in environment directorate of al najaf city. partition-gravimetric method used to quantify oil and grease in samples taken. the apparatus comprised: a. separatory funnel, 2-l, with tfe* stopcock. b. distilling flask, 125-ml. c. liquid funnel, glass. d. filter paper, 11-cm diam. e. centrifuge, capable of spinning at least four 100-ml glass centrifuge tubes at 2400 rpm. f. centrifuge tubes, 100-ml, glass. g. water bath, capable of maintaining 85°c. h. vacuum pump . i. distilling adapter with drip tip. j. ice bath. k. waste receptacle, for used solvent. l. desiccator. ____________ *teflon while the reagents used are included: a. hydrochloric , 1:1: mix equal volumes of either acid and reagent water. b. sodium sulfate, na2so4, anhydrous crystal. c. freon 113 . al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 45 procedure of analysis can be summarized as an oily water sample is extracted by a solvent. after separating the solvent (now containing oil) from the water sample, it is placed into a flask, which has been weighed beforehand. the flask is placed into a temperature controlled water bath, and the solvent is evaporated at a specific temperature, condensed and collected. after the solvent is evaporated, the flask now containing the residual oil, is dried and weighed. knowing the weight of the empty flask, the amount of residual oil can be calculated, this method is dependent and used in usa epa. (usepa, 1998). climatic parameters used in present study were measured by the digital climatic station in education faculty for girls in university of kufa. figure (2) shows the variations of oil and grease with time compared with some allowable limits according to iraqi and united states standards in al-kufa river station. monthly variations of no3, ph, t.u., cl, and pm are shown by figure. (3) to (7), while temperature, dust storm, and rain variations are represented by figure 8 during the period of study. table (3) shows analysis of variance (anova) for the regression model obtained, the prob (f) = 0.11, which means that there is a 89 % chance that at least one parameter is not equal to zero depending on the hypothesis used, therefore, the best significant relationship between the dependent variable and regression model is confirmed. table (4) shows the data statistics of the water quality parameters .the optimum correlation equation was found in the rank a of an exponential form with coefficient of determination r 2 equal to 0.791, was shown in table (5). the correlation matrix is shown in table (6), and table (7) shows regression variables results and 95% confidence intervals. figure (9) shows the plot of the model represents the parameters of euphrates river at al kufa river station during study period. 5. discussion the environmental impact of most releases of petroleum wastes would be minimal if the wastes remained at their points of release. unfortunately, wastes can migrate away from a release point by a number of pathways (reis, 1996). from figure (2) oil and grease ranged in al kufa river station throughout the study period between 0.3-6.4 mg/l, as iraqi standard limits 0.1 mg/l, those concentrations range from 3 to 64 times greater than iraqi standards. the highest value recorded was 6.4 mg/l in february, but the lowest value was 0.3 mg/l in november. the highest values 5.1, 6.4, 5.1 mg/l in january, february, and march, respectively, which recorded in heavy monthly rain fall of 20.7, 15.1, 13.5 mm, respectively. this agreed well with result gained by hunter et al., 1979 that presented a relationship between runoff and load. rain precipitation caused oil washing into surface water as runoff from roads and parking lots (nathanson, 2000). the word ‘‘runoff” indicates rainwater or snowmelt carried across land to water. runoff arises from non-point sources, and carries almost anything that water can carry as oil, grease, dirt, trash, animal waste, microorganisms, and chemical pollutants, including metals, pesticides, and fertilizers (hill, 2004). the variation of temperature, dust storm and rain with time during the period of the study is given in figure (8). table (6) shows that the temperature has high negative correlation (-0.89) with rain agreed very well iraqi climatic conditions. figures (3 to 7) show monthly variations with iraqi standard limits of no3, ph, t.u., cl, and pm during the period of the study. the value of oil &grease 5.1 mg/l in march, increased according to high values of no3, ph, cl as a result of sewage discharged to al kufa river from northern drainage of al kufa (2 km/north) and raw waste water discharged from al jimaah zone at 1 km / north of the station, al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 46 particularly in fertilizing season in neighbor area taking in consideration that agricultural, industrial, and domestic wastewaters discharged to surface waters are a source of chlorides and nitrates (metcalf & eddy, 2004). also, the value of oil &grease ( 6.3 mg/l) in july, increased according to high values of turbidity as a result of sewage discharged to al kufa river, this agreed very well with the result obtained by (hunter et al., 1979) that showed of runoff increase the fraction of hydrocarbons associated with the particulates increased. in addition, the oil and grease increased to reach 6.3 mg/l in july according to pm, t and ds values 153.85 , 46.1, 0.5 , respectively. this is a result of washing, polishing and lubricating of different types of vehicles covered by dust through the dusty weather by using oil products in large number of garages, some of them treating wastes in preliminary method and others discharging wastes to sewers affecting oil and grease increasing, especially when sewage is discharged to the river without treatment in wastewater treatment plant or illegal sewer pipe discharges. direct releases of oil into river were observed. second highest oil& grease value recorded in july (6.3) with high level of temperature, it sources were from diesel agriculture motors located on river banks, motor and other recreational boats in summer season release up to 30% of their fuel (hill, 2004). oil products were also discharged from different sizes of motors for electricity generation in all al najaf and al kufa quarters (residential, industrial and commercial zones) during working time especially through cooling processes by water and allow to water-oil mixture entering sewers to reach al kufa river. high oil and grease concentrations in shatt al kufa is also from grease formed in sewage which includes fats, waxes, free fatty acids, calcium, magnesium, soaps, mineral oils and other non-fatty materials (singh and singh, 2007). the sewage from kitchens, slaughter houses and restaurants contains grease (steel and mcghee, 1979; meenambal et. al., 2005; singh, 2007), therefore, oil and grease find their way to shatt al kufa from raw waste water discharged directly from al jimaah zone at 1 km / north of station. other sources of oil and grease in al kufa river are spills, oil leaking from vehicles, or released during accidents. in addition, petroleum hydrocarbons from atmospheric sources (e.g., automobile exhaust fumes) are deposited daily on road surfaces. when it rains, these oily deposits wash into nearby streams (weiner and matthews, 2003). this principle agreed well with the statistical analysis of the present study concerning the highest value of oil and grease through raining months and dust storm periods, as the particulate emissions are discharged from sources mentioned above, they are more rapidly separated and dispersed by the swiftly moving air, particulate smaller than 1 µm tend to remain suspension in the atmosphere indefinitely, whereas those larger than 1 µm tend to settle out under the force of gravity (nathanson, 2000). the particulates coated with petroleum hydrocarbons are settled, either precipitate directly on al kufa river or full deposited on road surfaces and reaches to river with rain. 6. conclusions the following conclusions are drawn on the basis of the results obtained from the present analysis: 1. oil and grease ranged in al kufa river station throughout the study period between 0.3-6.4 mg/l, those concentrations range from 3 to 64 times greater than iraqi standard limits. 2. the highest values of oil and grease were recorded in heavy rainy months, caused oil washing into surface water in runoff from roads and parks. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 47 3. the value of oil &grease in march, increased according to high values of no3, ph, t.u., cl as a result of sewage discharged to al kufa river from northern drainage of al kufa and raw waste water discharged from al jimaah zone. 4. it was noticed that the oil and grease increased according to pm, t and ds values as result of different activities involves, followed by discharging of polluted waters to sewers or into river directly. 7. recommendations -iraqi legislations should be severely restricting the discharge of oil & grease and other toxic substances by requiring pretreatment of wastewater. -conduct more studies on the relationships between different types of pollutants and human and animal health. -environmental monitoring programs to control the oil and grease contamination of al kufa river, and how they are affected by various environmental factors. -further studies on other potential pollutants in al kufa river and the hydrocarbon compounds such as pesticides and other residues in the river water and sediment. -more studies on the relationships between air pollution from industrial and traffic sources within river water and sediment. references a. n-hexane extractable material (hem; oil and grease) and agency, washington, d.c. -al-mayahi, a. w. t, 2005, "concentration of total hydrocarbons in some region of shatt al-arab river and its effected on benthic algae", m. sc. thesis, college of agriculture, university of basrah. -corbitt, r. a., 2004, "standard handbook of environmental engineering", mc graw-hill (www.digitalengineeringlibrary.com). federal register 64 (93):26315. u.s. environmental protection -geography dept., education faculty for girls / university of kufa, unpublished data. gravimetry. epa-821-r-98-002; 40 cfr part 136 (july 1, 2000); -hill, m. k., 2004, " understanding environmental pollution", cambridge university press -hunter, v., sabatino, t., gomperts, r., and mackenzie, m. j., " contribution of urban runoff to hydrocarbon pollution ", journal (water pollution control federation), vol. 51, no. 8 (aug., 1979), pp. 2129-2138published by: water environment federation, stable url: http://www.jstor.org/stable/25040687. -kaluarachchi, j. j., and j. c. parker, 1989, “an efficient finite element method for modeling multiphase flow”. water resources research, 25, 43-54. -liu , i., 1999, " environmental engineers handbook", crc press llc -meenambal, t., uma, r. n., and murali, k., 2005, "principles of environmental science and engineering", s. chand & company ltd, new delhi. http://www.digitalengineeringlibrary.com/ al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 48 -metcalf and eddy, 2004, "wastewater engineering treatment and reuse", fourth edition, mcgraw-hill. -ministry of environment, iraq, iraqi environmental legislations book. -nathanson, j. a., 2000, " basic environmental technology", prentic-hall, inc. -pankratz, t. m.,2001, "environmental engineering dictionary and directory " ,crc press llc. -pfafflin , j. , and ziegler, e.n., 2006, "environmental science and engineering", crc press taylor & francis group. -reis, j. c., 1996, "environmental control in petroleum engineering", gulf publishing company, houston, texas. silica gel treated n-hexane extractable material by extraction and -singh, g. and singh, j., 2007, "water supply and sanitary engineering", nem chand jain, delhi. -sleep, b. e., and sykes, j. f., 1993, “modeling the transport of volatile organics in variable saturated media”. water resources research, 29(3), 705-722. -steel, e. w., and mcghee, t. j., 1979, " water supply and sewerage", fifth edition, mcgrawhill. -u.s. environmental protection agency. 1998. method 1664, revision -weiner, r. e, and matthews, r. a., 2003,"environmental engineering", fourth edition, elsevier science (usa). table (1): the proposed models. rank equation description a m)xj...bxexp(axy kk21  b mxj...bxaxy kk21  c kk21 xj...xbxay  where; y = dependent variable. x1, x2, …, xk = the independent variables. a, b, c, …jk = model coefficients, and m = model constant term. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 49 table (2): description of independent and dependent variables in al kufa river station. table (3): variance analysis of variables in al-kufa river station variance analysis source df sum of squares mean square f ratio prob(f) regression 8 56.3780773 7.047259662 2.837972003 0.11029 error 6 14.89921603 2.483202672 total 14 71.27729333 type of variables variables detail in d e p e n d e n t x1 nitrate (no3, mg/l) x2 hydrogen ion concentration (ph) x3 turbidity unit (t.u., ntu) x4 chloride (cl, mg/l) x5 precipitated dust particles (pm, g/m 2 /month) x6 mean max. temperature (t, ºc) x7 dust storm (ds, no. of days) x8 monthly rain totals, (ra, mm) dependent y oil & grease (o&g, mg/l) al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 50 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 51 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 52 table (7): regression coefficients results and 95%confidence intervals regression variable results var. value standard error t-ratio prob(t) a -0.3461478 0.205221244 -1.686705499 0.14263 b 1.023656105 0.631589036 1.620762943 0.1562 c -0.07315679 0.067695274 -1.080677958 0.32135 d -0.037297617 0.01922619 -1.939938045 0.10045 e -0.014236224 0.006336813 -2.246590356 0.06575 f 0.279992317 0.157939786 1.772778881 0.12664 g 0.395297331 0.230554953 1.71454712 0.13725 h 0.258707332 0.149817547 1.726815972 0.13495 i -6.579121525 6.479378199 -1.015393966 0.3491 95% confidence intervals var. value 95% (+/-) lower limit upper limit a -0.3461478 0.502155861 -0.848303661 0.156008061 b 1.023656105 1.545435212 -0.521779107 2.569091317 c -0.07315679 0.165643565 -0.238800355 0.092486775 d -0.037297617 0.047044563 -0.08434218 0.009746947 e -0.014236224 0.015505548 -0.029741772 0.001269325 f 0.279992317 0.386462862 -0.106470545 0.666455179 g 0.395297331 0.564144915 -0.168847584 0.959442246 h 0.258707332 0.366588555 -0.107881222 0.625295887 i -6.579121525 15.85439051 -22.43351204 9.275268989 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 53 figure (1): map of the studying area in the national context. figure (2): variations of oil and grease with time compared with some allowable limits according to iraqi and us standards in al-kufa river station. * source: iraqi environmental legislations book **source: maximum allowable values in united states related to type of use published by california (liu, 1999). 0 1 2 3 4 5 6 7 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e c o il & g re a s e , m g /l variations of o&g with time o&g cocen. iraqi stand.* us stand.** al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 54 figure (3): variations of no3 with time figure (4): variations of ph with time figure (5): variations of turbidity with time figure (6): variations of chloride with time 0 20 40 60 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e c n o 3 , m g /l variations of no3 with time no3 5 6 7 8 9 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e c p h variations of ph with time ph iraqi stand. iraqi stand. 0 10 20 30 40 50 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e c t u rb id it y , n t u variations of turbidity with time turbidity iraqi stand. 100 150 200 250 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e cc h lo ri d e , m g /l variations of chloride with time chloride al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 55 figure (7): variations of precipitated dust particles with time figure (8): variations of temperature, dust storm and rain with time figure (9): plot model of parameters used in al kufa river station 0 200 400 600 800 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e cp re c ip it a te d d u s t ,g m /m 2 /m o n th variatios of precipitated dust with time precipitated dust 0 10 20 30 40 50 o c t n o v d e c j a n f e b m a r a p r m a y j u n j u l a u g s e p o c t n o v d e c variations of temp., dust storm, and rain with time temperature, c dust storm, days rain, mm pile raft foundation design for burj al-amir in a najaf city using finite element method al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 841 for burj foundationsraft -analysis of piled najaf city using finite elementa amir in-al method assistant lecturer. suhad abdulsattar hasan/ department of civil engineering college/ kufa university/e-mail suhadeng@yahoo.com abstract this study describes the process of analysis of a piled raft foundation for a high rise residential building (burj al-amir) on the najaf sea in iraq. piled raft foundation is a foundation used, in which the total load coming from the super structure is transferred to the soil by a load sharing mechanism between raft and pile. the present study attempts to do a three dimensional finite element analysis of piled raft foundation subjected to vertical load using plaxis program. various tests are done to explore soil properties, also parametric study to find effect the piled raft dimensions include pile spacing, number of piles, pile diameters, pile lengths for pile groups, raft thickness and raft dimension ratio (l/b) on piled raft foundation behavior are considered. it has been found that the maximum settlement of the piled rafts depends on the pile spacing and the number of piles.. the maximum bending moment in raft increases with increase raft thickness, decrease pile number and decrease in pile length. maximum and differential settlement decreases with increase raft thickness and uniform increase in pile length. in the scope of this study, the results of the parametric study are presented and design strategies for piled rafts are discussed. keywords: raft foundation, piles, analysis of foundation, finite element method. لبرج االمير في مدينة النجف مستند الى ركائزالحصيري الساس الا تحليل باستخدام طريقة العناصر المحددة سهاد عبد الستار حسن المحبوبي كلية الهندسة في جامعة الكوفة الصةالخ بحررفي منطقة األمير برجاقترح تسميته ب عالي االرتفاعبرج سكني ساساتحليل عملية توضح هذه الدراسة piled)حمرير المسرتند الرك رزرا السراس الهرو ا فري التمرمي المسرتدد األسراس نروع ق.في العررا النجف raft foundation) ، االسرراس تقاسر الحمررل بري عر ررنر للتربرة الرك خاللرهوالرذ ننتقررل الحمرل مرر mailto:suhadeng@yahoo.com al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 841 لنروع ثالثيرة األبعرا ال العناصرر المحردو ة باسرتددا تحليرلررنقرة الت عتمردا هذه الدراسة .والرزي ة الحمير جررا مجموعره مر ا وقرد تر plaxis. برنرام باسرتددا هالرأسري ه لألحمرا تعرضرساس المستدد عند اال أألساس أبعا تأثير نجا إلت اجرا تحليل نظر أنضاو ،تربة الموقع خما ص الفحوصات المدتبرنه إلنجا االسرراس افة الررك راسررة تررأثير ابعررا وتررأثير اروال,ررا، اضرر طارهرراوعررد ها وأق الرزررا دتباعرر شررملوالررذ ن .علرررررررررررررررررررررررررررررررررك سرررررررررررررررررررررررررررررررررلو االسررررررررررررررررررررررررررررررررراس المسرررررررررررررررررررررررررررررررررتدد الحمرررررررررررررررررررررررررررررررررير ونقمران عرد سرمكه تر ا ب نرا ة لعر االنحنرا باألسراس الحمرير المسرتدد القيمره العظمرك أن د وجدوق والتفاضلية لل,بور تقل ب نا ة سرم االسراس زما وجد ان القيمة العظمك رزي ة، والنقمان في رو الرزا ال وال نا ة المنتظمة في رو الرزي ة.. الحمير ساس, طريقة العناصر المحددة.الا اساس حصيرة, ركائز, تحليل :مفاتيح الداللة list of symboles the major symbols used in the text are listed below: gs = specific gravity of soil γmax = maximum unit weights γmin = minimum unit weights γdmax = maximum dry unit weights k = coefficient of permeability eo = initial void ratio cc = coefficient of curvature c = cohesion φ = friction angle b = width of raft l = length of raft es = young's modulus of soil ep = young's modulus of pile er = young's modulus of raft υs = poisson's ratio of soil υp = poisson's ratio of pile υr = poisson's ratio of raft q = the intensity of loading n = number of pile al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 dp = pile diameter lp = pile length tr = raft thickness s = pile spacing l/b = raft dimension ratio 1. introduction piled foundation is an old method to improve the load capacity and reduce the settlements for a raft foundation in areas with insufficient soil. the main purpose of this method is to transfer the load by the piles to firm rock or stiffer soil, i.e. further down in the ground. in conventional design of piled foundation, all loads are designed to be transferred via the piles to the soil. hence, neglecting the pressure, which could be, transferred from the raft directly to the soil by contact pressure. in the last decades geotechnical engineers have started to design piled foundation more optimized by allowing a part of the pressure to transfer directly from the raft to the ground. such a foundation, where the raft and the piles interact to transfer the loads to the ground is called piled raft foundation or piled raft. piled raft foundations have a complex soil-structure interaction. in this research the method for analysis of piled raft foundation are three dimensional finite element method 3d foundation plaxis. the objective of this research is to develop a numerical method for the analysis of piled rafts foundation. 2. review of significant related works the finite element method is one of the most powerful tools for the analysis of piled rafts. it requires the dissertation of both the structural foundation system and the soil. an early example of the analysis of a piled raft (the hyde park barracks) was given by hooper (1973), in which an ax symmetric model with eight nodded isoperimetric elements was used. in the analysis, approximation of the equivalent stiffness of the pile group was made such that each concentric row of piles was modeled by a continuous annulus with an overall stiffness that was equivalent to the sum of the stiffness's of the individual piles. chow and teh (1991) presented a numerical method to examine the behavior of a rigid piled raft embedded in a non-homogeneous soil. liu and novak (1991) employed the finite element method to examine the behavior of a raft supported by a single pile at the centre. wiesner (1991) presented a method for the analysis of a circular piled raft that was constructed in cairns. the raft was treated as a thin elastic plate and modeled by rectangular plate bending finite elements. clancy, p. and randolph, m. f. (1993) designed approach for piled raft foundations for tall buildings. smith and wang (1998) proposed the use of iterative techniques with the finite element method to examine the behavior of a non-uniformly loaded piled raft. prakoso and kulhawy (2001) analyzed piled raft foundations by the use of linear elastic and non-linear plane strain finite element models which involved the analysis of a three dimensional piled raft as a two-dimensional strip piled raft. fioravante and jamiolkowski (2005) performed centrifuge tests on models of a rigid circular piled raft in over consolidated clay and found that the load distribution al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 858 within a pile group under a rigid raft, in the working load range, is not uniform and is consistent with the prediction of a linear–elastic analysis. 3. results of experimental works and parametric study 3.1 soil tests an experimental testing program was conducted to determine the behavior of piled raft foundation installed in sand. sieve analysis for the sand soil carried out and a grain size distribution curve was obtained as shown in fig.(1) the grain size distribution is analyzed according to astm (d422-2001). physical properties, shear strength and compressibility parameters are shown in table (1). 3.2 parametric study this part deals with detail 3d analysis of piled raft foundations for building in najaf sea reign using the plaxis program, one-layer soil model is adopted. the numerical work is carried out on 3d plaxis analysis which 3d mesh is created by connecting the corners of the 2d triangular elements to the 15-nodded wedge elements, so that the size of the elements in y-direction is about equal to the average element size defined for the 2d mesh, fig.(2) shows the applied three dimensional finite element mesh and fig.(3) shows piled raft foundation model. extensive parametric studies were carried out with the variables pile spacing, number of piles, pile diameters, pile lengths for pile groups and raft thickness, raft dimension ratio (l/b) (b, l: the width and length of raft). the plane strain models are also simulated for the case of the variation in raft dimension ratio (l/b), fig.(4) shows piled raft foundation model configuration. details of piled rafts and pile groups in this parametric study are described below: 3.2.1 effect of pile spacing a 5x5 pile group is analyzed with variable pile spacing of 4d, 5d, 6d, 7d, and 8d. (d is the diameter of the pile which is equal to 1m) at (width x length) of the raft is (20×20, 25×25, 30×30, 35×35, 40×40) m respectively. the pile length is 20m. the raft is 3m thickness and the loading q is 10, 20 and 30 mn/m 2 . fig.(5) shows the maximum settlement (the maximum settlement of the raft is always found to be at the centre). with pile spacing. fig.(6) provides differential settlement (differential settlement is the difference in settlement values of the center point and the 4 corner points) and fig.(7) the maximum bending moment. the maximum settlement increased when the pile spacing increased from 4d to 8d at the same loading condition, this rate of increase in maximum settlement reached to 195 mm when q is 30 mn/m 2 and pile spacing is 8d. the differential settlement is 14 mm when q is 10 mn/m 2 but it reached to 74 mm at q is 30 mn/m 2 . when the pile spacing is 8d the bending moments are 56, 113 and 189 mnm/m width at q is 10, 20 and 30 mn/m 2 . 3.2.2 effect of number of piles a 5x5, 6x6 and 7x7 pile groups are analyzed with pile spacing varied from 8, 7 to 6d, the diameter of the piles d is 1m and the pile length is constant as 20m when the raft dimension are (40x40x3) m raft. the results are presented in fig.(8) and fig.(9). the increase in the number of piles doesn't have a lot of effect on maximum settlement when q al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 is 10 mn/m 2 but the effects are more at q is 30 mn/m 2 and when the number of piles increased from 25 to 36 and 36 to 49. 3.2.3 effect of pile diameter to examine the pile diameter effects, (40x40x3) m raft is analyzed with 5x5 piles and 8m pile spacing. the pile diameter varied from 0.6, 0.8 to 1m. in fig.(10), shows that the differential settlement increased clearly at q equal to 20 and 30 mn/m 2 and when the pile diameters are 0.8 and 1.0 m. 3.2.4 effect of raft dimension ratio if the (l/b) ratio of the raft is changed (40×40, 40×60, 40×80) m (width x length), the result is discussed when the raft thickness is 3m with 5x5 piles, 8m pile spacing, the diameter of the piles d is 1m and the pile length is 20m. fig.(11) shows the maximum settlement increased clearly with the (l/b) ratio when the q value are 20 and 30 mn/m 2 , also the bending moment decrease with increased in l/b ratio in fig.(12). 3.2.5 effect of raft thickness a (40x40) m raft is analyzed with the raft thickness varied from 1,2,3 to 4m, 5x5 pile group. the pile spacing is 8m, the diameter of the piles is 1m and the pile length is 20m. in fig.(13) the maximum settlement decrease slowly when raft thickness increased. in fig.(14) the differential settlement values become more convergent when the value of raft thickness 4 m for all values of q. 3.2.6 effect of varying pile length fig,(15),(16) and (17), shows the effect of varying the pile length (5,10,15,20) m, on the maximum settlement, the differential settlement and the maximum moment in the raft, as expected, the maximum settlement, differential settlement and maximum moment are decreased as pile length increased. 4. compares the computed results in this research with results obtained from other research. variation of maximum positive bending moments, maximum settlement and differential settlement with raft thickness between computed results obtained from this research and the result computed from elpla program (m. rabiei, 2005). in this parametric study the details of model properties are described in table (2), and are respectively illustrated on figs. (18), (19) and (20). the values shown in the figures indicate that for both cases there is reasonably good agreement between the computed results in this research with the other results with difference not exceeding 5%. 5. conclusions in this research, three dimensional finite element method under plane strain condition was applied to investigate the piled-raft performance under one layer soil condition. the geotechnical parameters were obtained several in-situ tests. based a series of case studies al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 were conducted on piled raft foundation in sandy najaf sea soil condition. although the examined piled raft conditions are limited, the following concluding remarks can be given: 1. the maximum settlement of the piled rafts depends on the pile spacing and the number of piles. 2. to reduce the maximum settlement of piled raft foundation, we need to increase the length of the piles but the differential settlement and the maximum bending moment in raft are not much effect by increasing the pile lengths. 3. the raft thickness has effect on the bending moments and differential settlement. the increase of raft thickness has much effect to decrease the differential settlement than its effect to decrease the maximum settlement. 4. the analysis indicates that thick rafts induce higher bending moments than thin rafts. references 1. anagnostopoulos, c. and georgiadis, m. (1998) "a simple analysis of piles in raft foundations”. geot. eng., vol. 29 (1), 71-83. 2. clancy, p. and randolph, m. f. (1993). "analysis and design of piled raft foundations". int. jnl. num. methods in geomechs, 17, 849-869. 3. fioravante, v. (2010). "load transfer mechanism between a pile and a raft with an interposed granular layer". in press on geotechnique 4. kuwabara, f. (1989). "elastic analysis of piled raft foundations in a homogeneous soil". soils found, 29(1), 82-92. 5. mandolini, a. (2003). "design of piled raft foundations", practice and development. in proceedings of the 4th international geotechnical seminar on deep foundations on bored and auger piles, ghent, van impe, w.f. ed. millpress, rotterdam, pp. 59-80. 6. poulos, h. g., and davis, e. h. (1980). "pile foundation analysis and design". new york: wiley. 7. poulos, h. g. (1993). "an approximate numerical analysis of pile raft interaction". int. jnl. num. anal. meths. in geomechs., 8. 18, 73-92. 9. poulos, h.g. (2001) "piled raft foundations – design and applications. geotechnique", vol. 50, (2): 95-113. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 854 10. small, j.c. and zhang, h.h. (2000) "piled raft foundations subjected to general loadings". developments in theor. geomechanics, ed. d.w. smith, & j.p. carter, balkema, rotterdam, 431-444. 11. www.plaxis.nl l autumn issue 2009 l plaxis bulletin. table (1): physical properties, shear strength and compressibility parameters. property value type of test gs 2.68 specific gravity of soil γmax 15.7 kn/m3 maximum unit weights γmin 13.8 kn/m3 minimum unit weights γdmax 17.9 kn/m3 standard compaction k 1.75 × 10 -4 cm/s coefficient of permeability eo 0.61 one dimensional consolidation cc 0.51 c 0 direct shear tests φ 39 table (2): the model properties used in elpla program (m. rabiei, 2005). b = l tr lp dp 20 m 0.7 m 10 m 1 m es ep=er υs υp= υr 20 mpa 30000 mpa 0.3 0.2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 855 figure (1): grain size distribution curve. astm (d422-2001). figure (2): 3d fe-model to the building foundation. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 figure (3): piled raft foundation model. figure (4): model configuration. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 0 50 100 150 200 250 3 4 5 6 7 8 9 pile spacing (xd) m a x im u m s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 figure (5): shows the relation between the maximum settlement at center of pile raft with pile spacing. figure (6): shows the relation between the differential settlement with pile spacing. 0 10 20 30 40 50 60 70 80 90 3 4 5 6 7 8 9 pile spacing (xd) d if fe re n ti a l s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 figure (7): shows the relation between the maximum moment with pile spacing. figure (8): shows the relation between the maximum settlement at center of pile raft with no. of pile. 0 20000 40000 60000 80000 100000 120000 140000 160000 180000 200000 3 4 5 6 7 8 9 10 pile spacing (xd) m a x im u m m o m e n t (k n m /m ) 10 mn/m2 20 mn/m2 30 mn/m2 0 50 100 150 200 250 20 30 40 50 60 m a x . s e tt le m e n t (m m ) number of piles, n 10 mn/m2 20 mn/m2 30 mn/m2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 851 figure (9): shows the relation between the differential settlement with no. of pile. 0 5 10 15 20 25 30 35 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 pile diameter,d (m) d if fe re n ti a l s e tt le m e n t ( m m ) 10 mn/m2 20 mn/m2 30 mn/m2 figure (10): shows the relation between the differential settlement with pile diameter. 0 5 10 15 20 25 30 35 40 45 50 20 30 40 50 60 number of piles, n d if fe re n ti a l s e tt le m e n t (m m ) 10 mn/ m2 20 mn/m2 30 mn/m2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 811 figure (11): shows the relation between the maximum settlement at center of pile raft with raft dimension ratio. figure (12): shows the relation between the maximum moment with raft dimension ratio. 0 20000 40000 60000 80000 100000 120000 140000 160000 180000 200000 0.9 1.1 1.3 1.5 1.7 1.9 2.1 ratio l/b m a x im u m m o m e n t k n m /m 10 mn/mm2 20 mn/mm2 30 mn/mm2 0 50 100 150 200 250 300 0.9 1.1 1.3 1.5 1.7 1.9 2.1 ratio l/b m a x im u m s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 818 figure (13): shows the relation between the maximum settlement at center of pile raft with raft thickness. figure (14): shows the relation between the differential settlement with raft thickness. 0 50 100 150 200 250 0.5 1.5 2.5 3.5 4.5 raft thickness (m) m a x im u m s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 0 5 10 15 20 25 30 35 0.5 1 1.5 2 2.5 3 3.5 4 4.5 raft thichness, t d if fe re n ti a l s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 811 figure (15): shows the relation between the maximum settlement at center of pile raft with pile length. figure (16): shows the relation between the differential settlement with pile length. 40 60 80 100 120 140 160 0 5 10 15 20 25 pile length (m) m a x . s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 0 10 20 30 40 50 60 70 80 90 100 0 5 10 15 20 25 pile length (m) d if fe re n ti a l s e tt le m e n t (m m ) 10 mn/m2 20 mn/m2 30 mn/m2 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 811 figure (17): shows the relation between the maximum moment with pile length. figure (18): shows the effect of raft thickness on maximum moment. 0 50000 100000 150000 200000 250000 0 5 10 15 20 25 pile length (m) m a x . m o m e n t (k n .m /m ) 10 mn/ m2 20 mn/ m2 30 mn/ m2 0 600 1200 1800 0 0.5 1 1.5 2 2.5 raft thicness (m) m a x .m o m e n t (k n .m /m ) elpia (2005) plaxis (current study) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 814 figure (19): shows the effect of raft thickness on maximum settlement. figure (20): shows the effect of raft thickness on differential settlement. 0 1 2 3 4 5 6 7 8 0 0.5 1 1.5 2 2.5 raft thickness (m) d if fe re n ti a l s e tt le m e n t (m m ) elpia (2005) plaxis (current study) 35 37 39 41 43 45 47 0 0.5 1 1.5 2 2.5 raft thickness (m) m a x . s e tt le m e n t (m m ) elpia (2005) plaxis (current study) al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 47 effect of curing method and insoluble residue in cement on the compressive strength of portland cement mortar asst. lecturer mohamed jassam mohamed university of babylon, college of engineering abstract in this experimental work, four different curing methods were applied namely including water, air, water heated-air and water heated –water. the results showed that the highest compressive strengths are attributed to the air cured under room temperature after 20hrs curing in heated water at each age. to verify the effect of insoluble residue on the compressive strength of portland cement, fine particles sand passing from sieve no. 200 and washing in hydrochloric acid were used as an insoluble residue. the portland cement was replaced by insoluble residue which varied between (0 7.0) % by weight. the results showed that the higher percentage of insoluble residue to 8.13% in cement mortar gives the lower the compressive strength by 12% of the control mortar compressive strength at 1 day .although of this reduction of strength, it was found that the compressive strength was still higher than the limits given by astm ,bs and iraqi standards. keywords: curing method, insoluble residue, portland cement, mortar, compressive strength. الخالصة: غمر بالماء,تركها بالهواء بدرجة حرارة الهذا البحث العملي تم تطبيق أربعة طرق لإلنضاج وهي في الغرفة,الغمر بالماء الساخن ومن ثم تركها في الهواء بدرجة حرارة الغرفة والنوع األخير من اإلنضاج هو الغمر خن ومن ثم الغمر بالماء بدرجة حرارة الغرفة. لقد أظهرت النتائج إن الطريقة األفضل لإلنضاج هي بالماء السا ساعة.أما الشق الثاني من البحث هو 02ترك النماذج بالهواء بدرجة حرارة الغرفة بعد الغمر بالماء الحار لمدة غاط للمونة حيث تم استخدام حبيبات الرمل التحقق من تأثير المواد الغير الذائبة في السمنت على مقاومة االنض وبنسب والمغسولة في حامض الهيدروكلوريك كمواد مضافة غير ذائبة 022الناعمة المارة من منخل رقم (% من وزن السمنت. إن النتائج بينت إن النسبة العالية من المواد الغير الذائبة والتي تصل 7-2تراوحت بين) % من مقاومة النموذج القياسي عند اليوم االول . 0.تعطي أقل مقاومة حوالي % في مونة السمنت 31.8إلى بالرغم من هذا النقصان في المقاومة فقد وجد إن قيم المقاومة للنماذج بقيت أعلى من الحدود التي حددتها .المواصفات األمريكية والبريطانية 1. introduction: curing is used to provide an appropriate environmental condition within a concrete structure, i.e. relative humidity and temperature to ensure the progress of hydration reactions causing the filling and segmentation of capillary voids by hydrated compounds. in a specific condition, curing duration to achieve an adequate hydration of portland cement mortars and concretes depends effect of curing method and insoluble residue in cement on the compressive strength of portland cement mortar 47 mainly on the chemical and mineralogical compositions. aci 308[2001] recommended practice suggests 7 days of moist curing for most structural concretes. however, the period of curing should be extended to 14 days when the cement contains supplementary cementitious materials, such as slag and fly ash, owing to the slow hydration reactions between supplementary cementitious materials and the calcium hydroxide. the process of this reaction requires the presence of water to produce the cementing compounds to contribute for filling the capillary voids. curing methods can be used once the concrete surface will not be damaged by the application of curing materials or water. the need for continuous curing is greatest during the first few days after placement of the concrete in hot weather. during hot weather, provided that favorable moisture conditions are continuously maintained, concrete can attain a high degree of maturity in a short time. water-curing, if used, should be continuous to avoid volume changes due to alternate wetting and drying [aci 308,2001]. the rate and degree of hydration, and the resulting strength of concrete and other properties, depend on the curing process that follows placing and consolidation of the plastic concrete. hydration of cement continues for years at a decreasing rate as long as the mixture contains water and the temperature conditions are favorable. once the water is lost, hydration ceases. curing of mortar and concrete is very essential for their strengths gain durability [al-gahtani, 2010]. aci 305[2002] requires that the temperature of the moist concrete be kept above 10 ◦ c. although concrete continuously maintained at a curing temperature of 10 ◦ c in the field will be protected against freezing, such concrete will develop compressive strength at about half the rate of a companion cylinder cured in the lab at 23 ◦ c (73 f). insoluble residue is a measurement of adulteration of cement, largely coming from impurities in gypsum and can be found by treating the cement with hydrochloric acid and sodium hydroxide [neville, 1995]. astm c 150 [2005] limits the insoluble residue in portland cement type i not higher than 0.75%. bs 12 [1996] and i.q.s no.5 [1984] set the limit for insoluble residue at 1.5% for cement not containing a minor additional constituent, and release the limit to 5.0% for cement including a minor additional constituent, such as granulated blast furnace slag, natural pozzolana, fly ash or filler. it is found that in modern cement, there is a higher content of c3s and a greater fineness than that of 40 years ago. as a consequence, cement mortar has, nowadays, a 28 days compressive strength perhaps 25 mpa higher than in 1925 [neville, 1995]. it seems that a higher insoluble residue in portland cement can be increased to a higher value without any negative effect on its strength. this premise was confirmed by poupongphan [1992]. they found that with 0.5% of finely crushed brick as an insoluble residue in portland cement type i, the compressive strength of cement mortar was reduced by 1.6%, and by increasing the insoluble residue up to 1.5%, this mixture resulted in a lowering of the cement mortar strength of less than 4% compared to the control cement mortar strength at 28 days. normal consistency and setting times are not changed by the addition of insoluble residue in cement. however, this premise still needs more data for support and confirmation that slightly increased rates of insoluble residue are not a major factor affecting its strength. 2. experimental program 2.1the mix and testing for curing effect: the mix proportion was w/c = 0.5, 1:3 cement and standard silica sand respectively. at first, cement and standard silica sand were mixed manually. after that, mix was put into the mixture, followed the mixing water was added to the mix and mixing was continued for two minutes, then the mortar was de-molded in 7.5cm cube specimens. after twenty-four hours casting, the six specimens were exposed to the each curing conditions as shown in the table 1. file:///c:/users/admin/desktop/effect%20of%20curing%20regime.htm%23ref_b0015 file:///c:/users/admin/desktop/effect%20of%20curing%20regime.htm%23ref_b0015 file:///c:/users/admin/desktop/effect%20of%20curing%20regime.htm%23ref_b0010 al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 47 2.2 insoluble residue: in this experiment, fine particles sand passing from sieve no. 200 and dissolving in hydrochloric acid were used as an insoluble residue. portland cement type i was replaced with the insoluble residue by 0%, 1.0%, 1.5%, 3.0%, 5.0% and 7% by weight of cement, plus the existing insoluble residue in cement as shown in table 2. the mixed cement was also used to prepare mortar in according to astm c 109 [2005] and demoulded into 7.5 cm cube specimens. after 24 hr, the molds were cured in water. the compressive strengths of mixed cement mortar were tested at the age of 1, 3, 7, 14, 28, and 60 days. at each date of testing, the data are the average of three specimens. 3. results and discussion 3.1 curing method: figure 1 shows that strength at 3, 7, 14, 28 and 60 days for om–wh–ac mix are more than the others, but the strengths of all are same at 90 days unless om–ac mix is less by 21.5%. at 90 days the strength of om–ac mix is minimized and there is strength loss about 10% compared to 60 days. therefore curing in the air is not practically recommended. it can be seen that for om–wc (control mix) the strengths are continuously increased at all ages and there is not any strength loss. the two mixes om–wh–ac and om–wh–wc which are in water heated for duration of 20 h with 60 °c after specimen de-molding. it is observed that for om–wh–ac mix, strength at 3 and 7 days are more about 21% and 20% than those for control mix at the same ages, while for om–wh– wc mix are more 8% and 4% than those for control mix. it is noted that for both mixes there are some strength loss at later ages. strength loss contents are 4.3% at 90 days and 3.2% at 60 days for om–wh–ac and om–wh–wc, respectively. comparing between the strengths for both mixes shows that it is better that the specimens are cured in air under room temperature after heating in the bath water. it has a significant effect in pre-cast concrete industry with advantages from economy. moreover, the strength improvements of om–wh–ac mix at 28 days and above are more than those of om–wh–wc mix and control mix at the same ages. 3.2. effect of insoluble residue on compressive strength of portland cement after the insoluble material was replaced in cement at the proposed percentage the cement and insoluble residues were mixed together to make the sample uniform. the proposed and the tested results of the insoluble residue material in the mix are shown in table 2. it can be seen from figure 2 and figure 3 that the higher the percentage of insoluble residue in cement to give the lower the compressive strength cements mortar. the compressive strengths of control sample vary from 8.1 mpa at 1 day to 40 mpa at 60 days. the sample ir0.5 (0.5% added) with 1.63% of insoluble residue has the compressive strengths of 7.9 mpa at 1 day and increases to 39.5mpa at 60 days. these strengths are lower than the control strength 2.4% at 1 day and 1.25% at 60 days, respectively. the compressive strengths of cement mortar with 2.13% of insoluble residue, sample ir1.0 (1.0% added), are, respectively, 7.7 mpa at 1 day and 39 mpa at 60 days. they are lower than the control strength by 4.9% at 1 day and by 2.5% at 60 days. it is noted that the reduction in strength due to insoluble residue is rather high at the early ages and tends to reduce when the age of cement mortar increases. at the highest amount of insoluble residue in the mix, 8.13%, in sample ir7.0(7.0% added), it is found that the compressive strength is still higher than the given limit by astm c 150 [2005]. for astm c 150 [2005], the cement mortar strength with 0.75% of insoluble residue has to be not lower than 12.4 mpa at 3 days and 19.3 mpa at 7 days for portland cement type i. sample ir7.0 gives compressive strength of mortar at 3 and 7 days equal to 17.2 and 25.9 mpa, respectively. this means that the insoluble residue to 8.13% in cement is not seriously harmful to its strength. it reduces the strength of cement mortar, but it is not the main factor affecting the strength of cement mortar. the value of the insoluble residue limited by astm c 150 [2005], 0.75% and i.q.s no.5 [1984], 1.5%, seems to be rather low and can be slightly increased without lowering the standard of cement. effect of curing method and insoluble residue in cement on the compressive strength of portland cement mortar 44 3.3 effect of insoluble residue on setting time of portland cement: the initial and final setting times of the control sample (only cement paste) were 108 and 195 min, respectively. with the replacement of cement by insoluble residue up to 7.0%, the setting times were changed little; they varied from 102 to 111 min for the initial setting time and from 195 to 210 min for the final setting time as shown in table 3. this may be because the particles size and particles shape of the insoluble residue were similar to that of the portland cement. this means that there is no effect of insoluble residue on setting time of cement paste by replacing insoluble residue up to 7.0%. 4. conclusion: 1. the curing under in air under room temperature after heating in the bath water has an increasing strength values at 3 and 7 days are more about 21% and 20% than those for control mix at the same ages. 2. it can be seen that for control mix, the strengths are continuously increased at all ages and there is not any strength loss otherwise others. 3. the higher percentage of insoluble residue to 8.13% in cement mortar gives the lower the compressive strength but is not seriously harmful to its strength. 4. it is noted that the reduction of strength due to insoluble residue is rather high at the early ages and tends to reduce when the age of cement mortar increases. 5. the value of the insoluble residue limited by astm c 150[2005], 0.75% and i.q.s no.5 [1984], 1.5%, seems to be rather low and can be slightly increased. 6. the setting times of cement was not significantly affected by finely sand as insoluble residue material in cement by replacing insoluble residue up to 7.0%. references: aci committee 308, recommended practice for curing concrete, mcp, american concrete institute, farmington hills, usa; 2001. a.s. al-gahtani, effect of curing methods on the properties of plain and blended cement concretes. construction build materials journal, 2010, pp. 308–314. aci committee 305, recommended practice for hot weather concreting, mcp, american concrete institute, farmington hills, usa; 2002. a.m. neville, properties of concrete, 3rd edition., pitman book, london, 1995, p. 10. astm c150, standard specification for portland cement, astm c 15095, in: annual book of astm, vol. 04.01, 2005. bs 12, specification for portland cement, 15th edition., british standards institution, london, 1996. p. poupongphan, s. boonsiri and v. karunyavanich," effect of insoluble material on properties of hydraulic cement" king mongkut's institute of technology thonburi, 1992. astm c 109, standard test method for compressive strength of hydraulic cement mortars , astm c10995, in: annual book of astm, vol. 04.01, 2005. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 47 i.q.s no.5, iraqi specification standard for portland cement, baghdad, 1984. table 1 mix proportion and curing conditions of ordinary portland cement mortars. symbol curing method curing condition om–wc (control) water after 24hr,immerged in the water under room temperature to the testing age. om–ac air after 24hr,left in the air under room temperature to the testing age. om–wh–ac air after 24hr, immerged in the heated water at 60 °c for duration of 20 hr, then left in the air under room temperature to the testing age. om–wh–wc water after 24hr, immerged in the heated water at 60 °c for duration of 20 hr, then immerged in the water under room temperature to the testing age. table 2 compressive strength of cement mortars that containing insoluble residue after adding insoluble materials. sample number added insoluble material (%) total insoluble residue (%) average compressive strength (mpa) 1 day 3 days 7 days 14 days 28 days 60 days control 0.0 1.13 8.1 19.0 27.8 30.8 35.9 40.0 ir0.5 0.5 1.63 7.9 18.6 27.6 30.5 35.4 39.5 ir1.0 1.0 2.13 7.7 18.4 27.2 30.1 35.2 39.0 ir1.5 1.5 2.63 7.6 18.1 27.1 29.9 34.8 38.9 ir2.0 2.0 3.13 7.5 17.9 26.7 29.5 34.3 38.4 ir3.0 3.0 4.13 7.4 17.6 26.2 29.4 34.1 38.3 ir5.0 5.0 6.13 7.2 17.2 26.0 29.1 33.7 38.1 ir7.0 7.0 8.13 7.1 17.2 25.9 28.6 33.5 37.8 i.r: insoluble residue table 3 setting times of cement paste that containing insoluble residue after added insoluble materials. sample added insoluble material (%) total insoluble residue (%) setting times (min) initial final control 0.0 1.13 108 195 ir0.5 0.5 1.63 108 210 ir1.0 1.0 2.13 109 195 ir1.5 1.5 2.63 111 210 ir2.0 2.0 3.13 109 210 ir3.0 3.0 4.13 109 195 ir5.0 5.0 6.13 105 210 ir7.0 7.0 8.13 102 195 effect of curing method and insoluble residue in cement on the compressive strength of portland cement mortar 47 figure 1 the relationship between the compressive strength of cement mortar and percentage of insoluble residue. figure 2 the relationship between the compressive strength of cement mortar and percentage of insoluble residue. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 78 figure 3 the relationship between the percentage of compressive strength of cement mortar and percentage of insoluble residue. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 513 investigation on an intermittent absorption refrigeration prototype powered by solar irradiation prof haroun a.k. shahad dhafer a. hamzah babylon university al-qadyisiah university email:hakshahad@yahoo.com email: thaaferawee@yahoo.com received 22 september 2015 accepted 12 october 2015 abstract in this study, a design and fabrication of intermittent solar absorption refrigeration unit was performed at hillah city in iraq)32.4 o , 44.4 o ). the absorption solar unit consists of parabolic trough concentrator (ptc) was used as solar rays mirror reflector with aperture area of 2 m 2 , carbon steel pipe inside a vacuum glass envelop with a diameter of 1.5 in as tubular receiver, condenser, storage tank, evaporator. the aqua ammonia solution) nh4oh)is used as working fluid with different concentration (25%, 30%, 35%, 40%). the validity and visibility of the unit were evaluated by measurements of pressures and temperatures at different parts of the unit during a year from may month 2014 to july month 2015. the maximum pressure and temperature is found to be 12 bar and 120 o c respectively. the coefficient of performance was in the range of 0.01-0.09. key words: solar, refrigeration, absorption الخالصة 32.4الدراسة ,تم انجاز تصميم وبناء منظومة تبريد امتصاصية تعاقبية في مدينة الحلة في العراقفي هذه o ) (44.4 o .الوحدة م 2عاكسة لألشعة الشمسية بمساحة فتحة تتكون من مركز على شكل حوض قطع مكافئ يستخدم كمرآة الشمسية االمتصاصية 2 , محلول هيدروكسيد يستخدمانج يعمل كمستلم انبوبي. 5.1فرغ من الهواء بقطر انبوب من الحديد الكربوني داخل غالف زجاجي م تحقيق ووضوح الوحدة قيم من خالل قياسات للضغوط %(.03%,01%,03%,21كمائع تشغيل بتركيز مختلف ) االمونيوم 513بار و 51ل ال . اقصى ضغط ودرجة حرارة وص 2351الى شهر تموز 2350شهر ايار ودرجات الحرارة خالل سنة من .3.30الى 3.35االداء كان يتراوح من درجة سيليليزية. معامل nomenclature a area ……………….……m 2 m mass …………………………….….…kg cp heat capacity ………………..kj/kg.k ptsc parabolic trough solar concentrator… coefficient of performance..…… qr heat received from solar radiation….mj cpc compound parabolic concentrator.. qev cooling capacity…...………….….mj g solar radiation ………………….…w/m 2 t time………..………..…………..……s mailto:thaaferawee@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 514 h solar insolation …………………….mj/m 2 v volume………….………………………m 3 hfg latent heat of evaporation for nh3….kj/kg v specific volume ……………………m 3 /kg 1. introduction energy shortage is sum of all fears in our earth on base of experts that sources of fossil fuel will be depleted in next 50 years[1].it is a fact that the countries development and welfare states depend on energy so researchers are increasingly focusing on renewable energy sources. another panic reason for concentration on renewable energy is global warming due to rise in global temperature (about 0.6 o c) according to un governmental panel on climate change who also warned that the temperature may further increase by 1.4-4.5 o c [2]. the issue remains of seeking an alternative to fossil fuel before deplete or destroyed the earth. solar energy can provide cheap and clean energy for cooling and refrigeration applications all over the world. solar refrigeration has become more attractive for cooling and refrigeration purposes. absorption is the process in which a substance assimilates from one state into a different state. these two states create a strong attraction to make a strong solution or mixture. the increase of heat in a solution can reverse the process [3]. the first evolution of an absorption system began in the 1700s.it was observed that in the presence of h2so4 (sulfuric acid), ice can be made by evaporating pure h2o (water)within an evacuated container. in 1810,it was found that ice could be produced from water in a couple of vessels connected together in the presence of sulfuric acid. as the h2so4 absorbed water vapor (to reduce heat), ice formed on the surface of water. sorption refrigeration systems have annexed a lot of interest due to their zero ozone attrition, so it is have favorabls of being environmentally zero impact. using of natural refrigerants such as ammonia, water, methanol, etc. it will be zero global warming(gwp). no moving parts, low –grade of heat requirement, less noise, low initial cost . all that will add fortuitous over the exiting vapor compression systems[4]. aqua-ammonia vapor absorption refrigeration systems which operate such that the generation of ammonia vapors takes place at the daytime only and the production of cold utilizing the generated ammonia vapors takes place at the night time only are known as intermittent-based operation systems. the operation of the system is approximately the same as that of the continuous operation system except that in such systems, both the generation and absorption processes take place intermittently in the same vessel. similarly, both the condensation and evaporation take place intermittently in the same heat exchanger. the water cooling system designed for this system works on the thermo siphon. different types of collector are used to concentrate the solar heat on the receiver unit( generation/absorption unit g/a). rivera et al. 2003[5] presents a theoretical performance of an intermittent absorption refrigeration system with compound parabolic concentrator(cpc) and nh3-lino3 as working pair fluid. they found that the maximum temperature was 120 o c and the coefficient of performance was 0.15-0.4 and the efficiencies were satisfactory the simplicity of the system. moreno et al.2012[6] performanced an experimental comparison between binary working fluid (nh3/lino3)and ternary working fluid (nh3/lino3/h2o) by using a compound parabolic trough (cpc). they found the coefficient of performance of ternary working fluid was up to 24% higher than those obtained with the binary mixture. the presence of water with refrigerant liquid form a problem during the expansion process due to choking phenomena so, sun[7] analyzed the performance of refrigeration systems operating with ammonia/water, ammonia/lithium nitrate, and ammonia /sodium thiocyanate mixtures. it was found that the ammonia/lithium nitrate, and ammonia /sodium thiocyanate mixtures were suitable alternatives to ammonia/water absorption systems. the important purpose of solar absorption unit is working in the rural area and desert area where no electricity grid is found, so hammad et al 2000[8] made a steel sheet cabinet 0.6*0.3*0.5 m, the cabinet was intended to store vaccine in the al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 515 remote desert area with suitable temperature and using solar powered aqua ammonia solution. the coefficient of performance (cop) was found 0.65 with refrigeration effect period of 8 hours. the most common cycles are nh3-h2o and h2o-libr that have served as standards for comparison in studying and developing new cycles and new refrigerant. abdulateef et al 2008[9] used thermodynamic properties to simulate three cycles nh3-h2o, nh3—lino3, and nh3-nascn. the purpose from this simulation was to compare the performance of three operating working fluid pairs. the results show that the nh3—lino3 and nh3-nascn cycles give better performance than nh3-h2o, because of no requirement for analyzer and rectifier. different solar sources are used as power for refrigeration absorption units, sierra et al 1993[10] used a solar pond to power an intermittent absorption refrigerator with nh3h2o solution . it was reported that generation temperatures as high as 73 o c and evaporation temperatures as low as -2 o c could be obtained. the thermal cop working under such conditions was in the range of 0.24-0.28. de francisco et al 2002[11] developed and tested a prototype of 2kw nh3-h2o absorption system in madrid for solar powered refrigeration in small rural operations. the test results showed that unsatisfactory operation of the equipment with cop lower than 0.05. in mexico a theoretical study of an intermittent absorption refrigeration system carried out by rivera et al 2003[12]. the designed system was driven by a compound parabolic concentrator (cpc) operated with ammonia –lino3. the results showed that in typical mexico weather, it was possible to produce up to 11.8 kg of ice with a thermal cop between 0.15 and 0.4 depending on the generation and condenser temperatures. bulgan (1995) [13] optimized the aqua-ammonia absorption refrigeration system (ars) in the light of the first law of thermodynamics. the system consisted of an evaporator, a generator, a condenser, a pump, expansionvalves and two heat exchangers. a theoretical model was developed for the ars. the coefficient of performance (cop) was maximized for various evaporator, condenser and absorber temperatures. li et al. 2002 [14] published an experimental study on the dynamic performance of a flat-plate solar solid-adsorption refrigerator for ice making operating with activated carbon/methanol. the experimental results showed that this machine could produce 4-5 kg of ice after receiving 14-16 mj of solar radiation with a surface area of 0.75 m 2 , while producing 7-10 kg of ice after receiving 28-30 mj of solar radiation with a surface area of 1.5 m 2 . hildbrand et al. 2004 [15] reported the results of the performance of an adsorptive solar refrigerator built in yverdon-les-bains, switzerland operating with the adsorption pair silicagel water. cylindrical tubes functioned both as the absorber system and the solar collector. the condenser was air-cooled and the evaporator contained 40 l of water that could freeze. the results showed that the gross solar coefficient of performance defined by the authors varied between 0.1 and 0.25 with a mean value of 0.16 . from above a strenuous efforts were exerted for validity, feasibility, modification and improvements in the weather conditions of researcher country. therefore in the present study a design , fabrication, experimental and theoretical prediction for solar insolation is achieved in iraq. he study used ammonia as refrigerant due to its thermodynamic properties[16] 2.system description the solar powered absorption refrigeration prototype was designed and fabricated to operate with the aqua ammonia (nh4oh) for a maximum capacity of 1 kg of ice/day for experimental purposes. it consists of a condenser, a storage tank, an expansion valve, by pass a capillary tube, an evaporator and a parabolic trough concentrator(cpc) as shown in fig.1 the cpc reflector was made out of an stainless steel sheet with a reflectance value of 0.85. the tubular receiver covered with a black paint with an emittance range from 0.28 to 0.5 and an absorptance range from 0.88 to 0.94 the other specifications show in table 1. the tabular receiver rounded by glass envelop to reduce the convection effect. as water evaporates at the operating conditions, a rectifier is al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 516 necessary in the system. the system operated solely with solar energy and no other moving parts were required. the condenser consisted of a heat exchanger composed of a helicoidally carbon steel coil , immersed in a water tank. the water inside the condenser is continuously circulated to control the temperature of the cooling water for experimental purposes. the coiled cylindrical storage tank had a capacity of 0.5 l. two expansion devices used : a capillary tube and an ordinary valve with 1.5 mm hole diameter. only one of these expansion devices was used at a time during the evaporation process. the capillary tube is recommended because it permits the automation of the evaporation process. the evaporator was made from carbon steel inside an insulated chest as shown in fig. 2. during the day, the aqua ammonia solution in the generator/absorber was heated by the solar radiation incident on the cpc until it reached the saturation temperature. then the ammonia is partially evaporated from the solution. the ammonia vapor goes a water cooled condenser, where it is condensed and then it is stored in the storage tank. at night, the temperature and pressure in the generator-absorber decreases because of the decrease of the ambient temperature. in this way, the pressures are inverted in the components in a natural way. the liquid ammonia passes through the expansion valve decreasing its pressure and temperature, producing the refrigeration effect in the evaporator. then it returns to the generator-absorber where it is absorbed by the weak solution starting the cycle again. 3.calculation parameters five main parameters were used in order to evaluate the performance of th experimental system: (i) the amount of ammonia produced in the generator, (ii) the insolation, (iii) the solar radiation incident on the cpc, (iv) the cooling capacity and (v) the solar coefficient of performance. the amount of ammonia produced in kg is the ratio between the storage tank volume to saturated specific volume of ammonia liquid as following: (1) the solar irradiation is the sum of the product of the solar radiation and time: ∑ (2) the energy incident on the cpc is calculated as: ∑ (3) the cooling capacity is the sum of latent heat and sensible heat at sub cooling state: (4) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 517 4.experimental results & discussion 4.1. variation of temperatures and pressures in order to experimentally evaluate the solar refrigeration system operation , more than 120 tests run are carried out during the year. however, only 50 tests were taken in account because of cloudy, dusty skies periods(normally longer than two hour). during the experimental test the pressure and temperature are the main parameters ,the pressure is logged every 60 seconds and the temperature is logged every 600 seconds. the temperatures and the pressure are measured experimentally with change of incident solar radiation(smodule) on parabolic trough concentrator. the efforts of experimental work are presented in the figs 3-12. the figures show the behavior of the temperatures and pressures for different parts of the solar unit. the figures are performed for the summer and winter months during the year. it can be seen from figs 3-12 that the pressure increase with increment of the solar radiation. the maximum pressure and temperature occur at maximum solar radiation at almost the midday. the maximum pressure and temperature reached to over 12 bar and 120 o c respectively during summer season and this is matched with the maximum load at this season. during the cold months as december , january, february, that the maximum pressure reaches to 4.5 bar . also the temperature of generator(tg/a )is more than the vapor solution temperature, since the generator represent the source of heating to the solution after the incident solar radiation decreasing the pressure and temperature will decrease too almost after 12.00 pm. so the system should be shutdown to prevent any lose in the pressure (pressure drop). 4.2 effect of concentration the concentration is an important parameter for the unit performance, due to the increasing in the concentration means a lot of releasing ammonia vapor. in the study different solution concentration used for tests (25%,30%,35%,40%). fig. 13 shows the maximum pressure reached in the cylindrical receiver against solution temperature in the generator unit. it can be observed that the pressure increases rapidly with the increment of the solution temperature and concentration. the increment in the concentration leads to increase in the ammonia vapor liberated. fig. 14 shows that the liberation of ammonia vapor occurs at low temperature when the solution concentration is high , while the low concentration needs higher temperature to liberate ammonia vapor . fig. 15 shows that the pressure of generator is higher at high concentration due to the larger ammonia vapor liberated as shown in fig.16. the figure shows the relation between concentration and mass of ammonia vapor produced. it can be observed that the amount of ammonia vapor increases with increasing the concentration. this increasing in mass produced depends on energy received by the cpc and solution concentration. 4.3. experimental coefficient of performance the coefficient of performance depends on concentration as well as the pressure achieved in the unit base on the ammonia vapor is completed condensation (saturated liquid at environment temperature). the refrigeration effect( cooling capacity) occurs at night, when the environment temperature reaches to saturated ammonia liquid temperature. high pressure for ammonia liquid (refrigerant) means high saturated temperature, then sensible heat will add with latent heat of evaporation to increase the coefficient of performance. figure 17 shows the coefficient of performance(cop) for the solar intermittent system operating with aqua ammonia solution. different solution concentrations had been tested in the experimental study (25%,30%,35%,40%). it can be observed that the higher performance is obtained at higher concentrations due to large al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 518 ammonia vapor produced. the high concentration gives more ammonia released and high pressure difference between evaporator and condenser. in any refrigeration system the coefficient of performance increases with increasing the pressure difference between evaporator and condenser( or generator). figure 18 shows the effect of increasing pressure on the increasing of cop. high pressure in unit leads to high latent heat for evaporation after expansion valve. 5. conclusions in this study a novel solar intermittent refrigeration system for ice production was developed and designed with aqua ammonia solution to match with iraqi weather conditions. the natural refrigerant (ammonia ) is suitable for intermittent absorption refrigeration unit, due to high latent heat for evaporation. it is obvious that the solar irradiation satisfies the unit requirements. the parabolic trough concentrator (ptsc) is suitable for intermittent absorption refrigeration unit, due to the high temperature and pressure can be obtained during the day. the high pressures and temperatures present during all months suitable for unit operation. the condenser unit can be neglected at low ammonia amount used, due to high pressure performed during the operation. the amount of aqua ammonia used can be increase for present study (more than 10 kg) due to large aperture area for ptsc. so the coefficient of performance will be increase with increase of released ammonia. the environment temperature have important role in intermittent absorption unit for saturated conditions purpose for ammonia liquid. the expansion device is more efficient than the capillary tube due to the change in the inlet pressure for ammonia liquid in different seasons and days. references [1] john r. fanchi, energy in 21st century, published by world scientific publishing co. pte. ltd.2005. [2] us environmental protection agency, global warming climate, http://yosemite.epa.gov/oar/globalwarming.nfs/content/climate.html, 2006. [3]hassam h, mohamad a. a review on solar cold production through absorption technology.renewableandsustainableenergyreviews2012;16:5331–48. [4] wang rz, wu jy, dai yj, wang w, jiang zhou s. adsorption refrigeration. china machine press; 2002, p. 1–3 [in chinese]. [5] c.o. rivera, w. rivera. modeling of an intermittent solar absorption refrigeration system operating with ammonia-lithium nitrate mixture. solar energy material& solar cells 76(2003)417-427. [6] g. moreno-quintanar, w. rivera, r. best. comparison of the experimental evaluation of solar intermittent refrigeration system for ice production operating with the mixtures nh3/lino3 and nh3/lino3/h2o. [7] sun dw. comparison of the performances of nh3/h2o, nh3/lino3 and nh3/nascn absorption refrigeration systems. energy conversion and al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 519 management 1998;39(5/6):357-68. [8] hammad m, habali s.(2000). design and performance study of a solar energy powered vaccine cabinet. applied thermal engineering 20 pages 1785-1798. [9] j. m. abdulateef, k. sopian and m. a. alghoul. optimum design for solar absorption refrigeration system and comparison of the performance using ammonia-water, ammonia lithium nitrate and ammonia sodium thiocyanate solution. international journal of mechanical and materials engineering (ijmme), vol. 3 (2008), no.1, 17-24. [10] sierra, fz., best, r. and holland, fa., 1993. experiments on an absorption refrigeration system powered by a solar pond. heat recovery systems &chp, vol. 13, pp. 401-408. [11] de francisco, a., illanes, r., torres, jl., castillo, m., de blas, m. and prieto, e., 2002. development and testing of a prototype of low-power water-ammonia absorption equipment for solar energy applications. renewable energy, vol. 25, pp. 537-544. [12] rivera, co. and rivera, w., 2003. modeling of an intermittent solar absorption refrigeration system operating with ammonia/lithium nitrate mixture. sol energy mater sol cells, vol. 76, pp. 417-27. [13] bulgan, a. t., 1995. optimization of the thermodynamic model of aqua-ammonia absorption refrigeration systems. energy conversion management, vol. 36, no. 2, pp. 135143 . [14] li m, wang rz, xu yx, wu jy, dieng ao. experimental study on dynamic performance analysis of a flat-plate solar solid-adsorption refrigeration for ice maker. renewable energy 2002;27:211-21. [15] hildbrand c, dind p, pons m, buchter f. a new solar powered adsorption refrigerator with high performance. solar energy 2004;77:311-8 [16] abbas a.s al-jeebori. fundamental of air conditioning and refrigeration. dar alkutub& documentat baghdad cataloguing no (15)-2007. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 520 table (1): overall dimensions for collector unit item value/type collector aperture area 2 m 2 aperture width 106 cm width to focus ratio 4.6 rim angle 41 o receiver diameter 1.5 in. mode of tracking manual seasonal adjustment geometric concentration ratio 7 figure (1): schematic of solar powered intermittent absorption unit al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 521 figure (2): a photograph of the solar absorption refrigeration module al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 522 0 2 4 6 8 10 12 14 0 100 200 300 400 500 600 700 800 900 1000 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 p re ss u re ( b a r) s o la r ra d ia ti o n w /m 2 local time (hour) figure 4 development of generator pressur and solar received with time in sunny day june.2014 solar radiation received pgenerator/absorber 0 100 200 300 400 500 600 700 800 900 1000 0 20 40 60 80 100 120 140 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 s o la r ra d ia ti o n w /m 2 t e m p e rt u re o c local time (hour) figure 5 development of generator, ammonia vapour,ambient temperture and solar radiation received with time in sunny day july.2014 tgenerator absorber tammonia vapour tambient solar radiation received 0 2 4 6 8 10 12 14 0 100 200 300 400 500 600 700 800 900 1000 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 p re ss u re ( b a r) s o la r ra d ia ti o n w /m 2 local time (hour) figure 6 development of generator pressur and solar received with time in sunny day july.2014 solar radiation received pgenerator/absorber 0 100 200 300 400 500 600 700 800 900 1000 0 20 40 60 80 100 120 140 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 s o la r ra d ia ti o n w /m 2 t e m p e rt u re o c local time (hour) figure 3 development of generator, ammonia vapour,ambient temperture and solarradiation received with time in sunny day june.2014 tgenerator absorber tammonia vapour tambient solar radiation received al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 523 0 2 4 6 8 10 12 14 0 100 200 300 400 500 600 700 800 900 1000 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 p re ss u re ( b a r) s o la r ra d ia ti o n w /m 2 local time (hour) figure 8 development of generator pressur and solar received with time in sunny day august.2014 solar radiation received pgenerator/absorber 0 100 200 300 400 500 600 700 800 900 1000 0 20 40 60 80 100 120 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 s o la r ra d ia ti o n w /m 2 t e m p e rt u re o c local time (hour) figure 7 development of generator, ammonia vapour,ambient temperture and solar radiation with time in sunny day aug.2014 tgenerator absorber tammonia vapour tambient solar radiation received 0 100 200 300 400 500 600 0 10 20 30 40 50 60 8 :0 0 8 :2 0 8 :4 0 9 :0 0 9 :2 0 9 :4 0 1 0 :0 0 1 0 :2 0 1 0 :4 0 1 1 :0 0 1 1 :2 0 1 1 :4 0 1 2 :0 0 1 2 :2 0 1 2 :4 0 1 3 :0 0 1 3 :2 0 1 3 :4 0 1 4 :0 0 s o la r ra d ia ti o n w /m 2 t e m p e rt u re o c local time (hour) figure 9 development of generator, ammonia vapour,ambient temperture and solar radiation with time in sunny day nov.2014 tgenerator absorber tammonia vapour tambient solar radiation received 0 1 2 3 4 5 6 0 100 200 300 400 500 600 700 800 900 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 p re ss u re ( b a r) s o la r ra d ia ti o n w /m 2 local time (hour) figure 10 development of generator pressur and solar received with time in sunny day nov.2014 solar radiation received pgenerator/absorber al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 524 0 50 100 150 200 250 300 350 400 450 500 0 10 20 30 40 50 60 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 s o la r ra d ia ti o n w /m 2 t e m p e rt u re o c local time (hour) figure 11 development of generator, ammonia vapour,ambient temperture and solar radiation with time in sunny day dec.2014 tgenerator absorber tammonia vapour 10 10.5 11 11.5 12 12.5 12 13 14 13 14 16 c o p pmax (bar) figure 32 coefficient of performance versus generator pressure 0 0.5 1 1.5 2 2.5 3 3.5 4 0 50 100 150 200 250 300 350 400 450 500 8 :0 0 8 :3 0 9 :0 0 9 :3 0 1 0 :0 0 1 0 :3 0 1 1 :0 0 1 1 :3 0 1 2 :0 0 1 2 :3 0 1 3 :0 0 1 3 :3 0 1 4 :0 0 p re ss u re ( b a r) s o la r ra d ia ti o n w /m 2 local time (hour) figure 12 development of generator pressur and solar received with time in sunny day dec.2014 solar radiation received pgenerator/absorber 0 2 4 6 8 10 12 14 16 18 20 0 20 40 60 80 100 120 p ( b a r) t (oc) figure 13 total pressure versus temperture of solution concentration 25 % concentration 30 % concentration 35 % 40 45 50 55 60 65 70 75 80 20 30 40 t ( o c ) concentration % figure 14 initial generation temperture (oc) concentration 25 % concentration 30 % concentration 35 % concentration 40 % al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 525 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 20 25 30 35 40 45 c o p concentration % figure 17 coefficient of performance (cop) for different concentration 25% 30% 35% 40% 200 220 240 260 280 300 320 340 360 20 30 40 50 m n h 3 ( g ) mass concentartion % figure 16 mass of ammonia produced during the generation process 25% concentartion 30% concentartion 35% concentration 40% concentration 9 10 11 12 13 14 15 16 17 20 25 30 35 40 45 p (b a r) concentration % figure 15 generator/ absorber operating pressure (bar) concentration 25 % concentration 30 % concentration 35 % concentration 40 % 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 c o p pmax (bar) figure 18 coefficient of performance versus generator pressure improvement of expansive soil properties (l.l, p.l, p.i) using ordinary portland cement al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 422 improvement expansive soil properties (l.l, p.l, p.i) using ordinary portland cement saba. m. shaheed asistance lecture collage of engneering/ university of al-qadisiyah received 21 april 2015 accepted 5 july 2015 abstract: the idea of this research is to improve the properties of expansive soil, such as, liquid limit, plastic limit and shrinkage limit by adding different amount of ordinary portland cement to expansive soil. all variable which effect on soil properties, such as: amount of water, the ratio of compacting, time of mixing and the time for testing should be constant, to determine the differences in liquid limit, plastic limit and shrinkage limit for expansive soil with and without different amount of ordinary portland cement. four different percentages of ordinary portland cement were used in those experiments, 2.5, 5.0, 10, and 15% by dry weight, these amounts were added to the expansive soil, mix each ratio with an amount of expansive soil and then samples were compacted by a steel rod. after that, the samples were cured for 7 days by covering them with a damp cloth. the samples were weighted and the dimension was measured on the first day; then on the seventh day; and finally on the 28th day to see the differences in weight and volume for each sample. the results were compared to find out which percentage indicated more effect on expansive durability in 7 and 28 days. liquid limit and plastic limit were reduced when the amount of cement is equal to 5%, and also the ratio of shrinkage, reduced when the amount of cement was equal to 5%. while the liquid limit, plastic limit and ratio of shrinkage seem to be constant when the amount of cement is more than 5%. so the ratio of 5% cement seems to be more suitable and more economical to use to improve the expansive soil properties. key words: expansive soil properties, liquid limit, plastic limit, plasticity index, shrinkage situation. تحسين خواص الترية الطينية الضعيفة )حد الليونة, حد المرونة( باستخدام السمنت البورتالندي العادي صبا محمد شهيد كلية الهندسة /جامعة القادسية 1. introduction: expansive soils are that type of soil which expand in volume when water content changes and it is found in many parts of the world; america, asia, russia, the middle east, and many other places. this kind of soil is found in these regions because they consistently have periods of rainfall and drought which causes significant soil instability, so they have repeating wet and dry cycling. cracks and deformation are noticeable during construction (yucel et al. 2007). this kind of soil has many al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 423 problems related to the civil or geotechnical engineering especially with heavy construction or highways and roads. expansive soil problems have appeared as cracking and destruction of highway embankments, pavements, railways, roadways, slab-on-grade members, building foundations, water lines and drain lines, canal and reservoir linings, and irrigation systems (gromko, 1974; mowafy et al. 1985; kehew, 1995). the changing in soil volume called swelling and shrinkages, which is happened in soil whenever it is wet, because the water will fill all the voids between the soil particles. hence, the particles will be spaced apart from each other and that leads to an increase in the soil volume (gulsah yesilbas, 2004). expansive soil has the ability to swell and shrink when; affected by water volume, and this property has numerous effects on construction of basements and foundations causing significant problems to the constructions. the water content is coming from rain, flooding, groundwater and lakes; also this kind of soil is very common in agricultural areas, where there is a lot of plants there. the property which makes soil particles repeatedly expand when it is wet and shrink when it is dry, especially if the groundwater table is high-, is called fluctuation. fluctuation causes many problems in civil engineering because the soil volume can change. the change in volume happens because of the water pressure and because of the small bond between clay minerals, and if it is not considered in design, the issue may in the future cause construction collapse. for expansive soil, which mostly contains small particles of clay and when the water fill the voids the clay mineral particles made are dispersed as layers which are tending to move away from each other because of thermal energy, resulting from a melting of clay particles in water (craig, 2004). figure (1) describe the soil particle shape, the fine-grained particles are damage the stability when the soil is in a wet condition. figure (2) explains the kind of clay minerals group; (a): montmorillonite, (b): illite and (c): kaolinite, which are crystalline hydrous aluminosilicates and those kinds have different behaviour when water is added to the soil. many studies have been done to see or discover how engineers can improve the soil's ability and increase the soil strength. many additives have been added to the soil such as cement, fly ash fibres, polymers, and other materials to improve soil workability and increase both soil stabilisation and compressive and shear strength, then these additions are mixed with soil in depth (1218) inches. after that water is added to the soil mixture for 24-48 hours, and then the ground surface will be compacted to improve the soil strength and the soil durability (western stabilisation). the most common ways of achieving soilstabilisation are: • use cement powder to stabilise the expansive soil, and to improve the mechanical properties of soils. cement treatment was being used widely and positive effects of cement on the performance of soils have been recognised (balmer 1958; mitchell 1976; uddin et al. 1997; lo and wardani 2002). cement is a composite of oxides of calcium, silica, alumina and iron. this additive has the same results as lime stabilisation and it has many other useful properties such as very quick stabilisation and does not need mellowing time (farid et al., 2009). • use lime-stabilisation this is very commonly used and it is an economical choice. lime is added to the clay soil as a presence of water and as a result optimum water content, shrinkage limit and soil strength are increased. while swelling potential liquid limit means that plasticity index and maximum dry density of soil is decreased (sherwood. 1993). • fly ash stabilisation was used with expansive soil, and this additive has the same results as the lime or aggregate stabilisation (yucel et al. 2007). • aggregate-soil stabilisation is by using aggregate, either natural aggregates or aggregates which are produced from crushed concrete or crushed asphalt, which result from construction demolition. using aggregate or recycling demolished materials has many advantages, as it is more economical and it is more environmentally friendly (sherwood, 1995). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 424 • add different materials for stabilisation, which contain natural additives and could increase soil stability, such as; steel slug, particle board, drywall, gypsum, dimensional lumber, and plywood (special condition). 1.1 soilcement stabilisation soil stabilisation means any process which leads to change and improves the soil properties, so the engineers could use it in their construction without failure, (winterkorn, 1955). several methods are used to improve the properties of soils, such as; the stability, strength and load-bearing capacity, as well as durability. high strength and enhanced rigidity are achieved by reducing the void space between particles and preventing fluctuation; (swelling and shrinkage). soil stabilisation by cement and lime are very commonly used, so the amount of cement which is used in soil stabilisation is affected by the durability requirement as well as depending also on the type of soil and the required properties, in general the range of cement content is from 3 to 16% by dry weight of soil, and whenever clay content increases the amount of cement increases too. any type of cement could be used in soil stabilisation, but the most common type is ordinary portland cement. suitable soil stabilisation is determined by two factors, the first factor is satisfactory mixing between the soil and cement, the second factor is adequate hardening for the soil and cement mixture after mixing and compacting (bell, 1993). when cement powder is added to the expansive soil particles, the mixture of fine particles of cement with water will fill most of the soil voids and is made into a mixture with electric discharge, which is both positively and negatively conducting; working to increase the bonding strength between soil molecules (craig, 2004). however, when cement is added to clayey soils in the presence of water, a number of reactions happen leading to the change of soil properties such as cation exchange, carbonation, pozzolanic, and fluctuation (al-rawas et al., 2005). the cation exchang takes place between the cations associated with the surfaces of the electrically charged clay particles and the calcium cations of the cement. clay particles become close to each other because of the effect of cation exchange and the attraction causes fluctuation. fluctuation is primarily responsible for the change the engineering properties of clayey soils. while; cement stabilisation develops from the cementitious links between the calcium silicate and aluminate hydration products and the soil particles (croft, 1968; al-rawas et al., 2005). 1.1.1 types of soil-cement stabilisation all soil types could be stabilised with cement except the high plasticity soil or high organic soil, and the soil which has a particle size more than 20mm, because it would not have efficient surface finishing. additionally, the finer particle size of less than 0.18mm should not be more than 50% soil and the soil with many different particle sizes is more suitable to mix with cement to achieve reasonably good economic results. soil with 5-35% fines yield is often a more economical soilcement mixture, if the soil particle size is more than the recommended ratio, the cement will cover the particle and they will be bound and pasted in their contact points (bell, 1996). 1.1.2 properties of soil-cement stabilised the properties of cementstabilised soil are affected by two factors, first, is the amount of cement which is added. second, is the volume of compacting. when the amount of cement increases, the bearing capacity and durability increases too. the soil tends to be stiffer because the ability to swell is reduced and it has a tendency towards shrinkage. the adequate compaction causes an increase in mixture density because the cement moisture fills the space between the clay minerals. the width of cracks in cement-soil after drying tends to be smaller and nearly closes the space in clay more than in cement-soil with sand. also the compaction should be done in two hours of mixing soilcement to avoid hardening of the mixture because of the cement hydration (bell, 1996). there is al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 425 an affect for sulphate content in soil on ordinary portland cement, but in this study the affect were be summed to be neglected. 1.1.3 soil-cement application the soil-cement used in many types of construction, for example is used as a base under the pavement to avoid fine-grained pumping to the pavement surface, or it is used to protect the sloping in canals, coastal cliffs, dams, highways, or it is used when a massive full replacement is required to provide a rigid support to the foundations, or under the pile base (bell, 1993). it is also used in temporary roads, parking, airport runways, and house foundations and in building block manufacture. although the amount of cement which is added to the soil depends on the soil type and construction type (gillott, 1968). 2. methodology this study is based on a laboratory experiment of expansive soil as shown in figure no. 3. using a sample of expansive soil stored in the geotechnical laboratory in portsmouth university in the uk, with dry ordinary portland cement that was added to dry expansive soil in the different percentage ratio of weight and then mixed with a constant water ratio to see the effect of cement on soil properties, such as, liquid limit, plastic limit and shrinkage limit, and then to analyse and compare between the percentages of cement. 2.1 sample preparation four different percentages of ordinary portland cement were used in those experiments, 2.5, 5.0, 10, and 15% by dry weight, these amounts were added to the expansive soil, mix each ratio with an amount of expansive soil and then samples were compacted by a steel rod. after that, the samples were cured for 7 days by covering them with a damp cloth. the samples were weighted and the dimension was measured on the first day; then on the seventh day; and finally on the 28th day to see the differences in weight and volume for each sample. the results were compared to find out which percentage indicated more effect on expansive durability in 7 and 28 days. in this study many types of lab experiment were undertaken to determine the changes in soil properties. the lab experiment consisted of : ind out plastic limit for soil. 2.2 soil property index 2.2.1 liquid limit liquid limit is defined as moisture content in the soil when it changes from a plastic to a viscous fluid figure 4 state which is expressed as a percentage of the weight of the oven dried soil, at the boundary between the liquid and plastic states of consistency. subsequently, the liquid limit defined by british standard 1377 -1990, is a water content corresponding to a cone penetration of 20 mm. according to british standards all values of water content are expressed in a whole number if the value is above 10%. 2.2.2 plastic limit the plastic limit is defined as the moisture content when the soil changes from a semi-solid to a plastic (flexible) state figure 5 which is expressed as a percentage of the weight of the oven-dry al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 426 soil, at the boundary between the plastic state and semisolid states of consistency. it is the moisture content when the soil just begins to crumble and rolled into a thread ⅛ in. (3 mm) in diameter on a ground glass plate or other acceptable surface. according to british standard 1377 -1990 all values of water content are expressed in a whole number if the value is above 10%. 3.2.3 shrinkage limit after models were be done in process at section 2.1,all the dimensions were measured on the first day; then on the seventh day; and finally on the 28th day to see the relative shrinkage in volume. the samples were cured for the first 7 and 28 days by covering them with a damp cloth figures 6 and 7. 3. results and dissection as indicated by table 2, the ratio of loss in soil weight and shrinkage in sample volume in 28 days for pure expansive soil is more than the ratio in 7 days. this occurs because of the samples drying during the experiment time. tables 3, 4, 5, and 6, show the ratio of loss in soil weight and shrinkage in sample volume during 28 days is less than the ratio in 7 days, and that is because of the additives of cement which were added to the soil. the particles of cement absorb the water and reduce water evaporation, thus shrinkage is reduced. cement treatment prevents volume changes because it produces a resistant layer that will protect the soil below from seasonable variations in moisture content (portland cement association). also, when cement adds to pure expansive soil the reaction between cement and soil reduces the amount of silt and clay size particles. the silt and clay size particles damaged the soil stability when the soil is in a moist or wet condition (portland cement association). figure 8 shows the liquid limit decreases slightly between the pure soil point until it reaches a pure soil with 5% cement ratio, and then tends to be constant, while the plastic limit increases gradually for pure soil with 5% cement and then tends to become constant, while the plasticity index decreases gradually until it reaches a pure soil with 5% cement ratio, after which it increases very slightly until it reaches pure soil with a 15% cement ratio. figures 9, 10, 11, 12 and 13 show the results of liquid limit for pure soil with and without different amounts of soil, and the liquid limit is equal to the water content value at 200 of penetrometer reading. thus, could be noticed the liquid limit decrease when the amount of cement increase table 1, but the decline in the value of the liquid limit at least when the amount of cement exceeds 5% by dry wet. 4. conclusion as a result, it could be said that all amounts of ordinary portland cement have an effect on the soil properties, such as liquid limit, plastic limit and plasticity index in different ratio. also, the ratio of shrinkage has been affected by all the amounts of cement, but in different ratios. the amount of cement which is equal to 5% by dry weight when added to the expansive soil has more effect and reduces the ratio of shrinkage in the soil more than the other amounts, because the values of liquid limit, plastic limit and plasticity index seem to be constant when the ratio of cement is more than 5%. so, as a result of this research it could be said the 5% amount of cement by dry wet has more effect on shrinkage limit and it could be used to control or reduce the shrinkage in expansive soil. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 427 5. references al-rawas, a.a., hagoa, a.w. and al-sarmib, h. 2005. effect of lime, cement and sarooj (artificial pozzolan on the swelling potential of an expansive soil from oman. building and environment, 40: 681-687. balmer, g. g. (1958). shear strength and elastic properties of soil-cement mixture under triaxial loading, portland cement association research and development laboratories. bell f. g., (1993). engineering treatment of soil. soil stabilisation. e&fn spon, chapman& hall, 2-6 boundary row, london se1 8hn, uk. bell, f.g. 1996. lime stabilization of clay minerals and soils, engineering geology; 42: 223-237. craig. r. f., 2004. graig’s soil mechanics 7th edition. tj international ltd, padstow, cornwall. london. croft. j. b., 1968. the problem of predicting the suitability of soil for cementations stabilisation. engineering geology, 2, 397-424. farid sariosseiri a, balasingam muhunthan effect of cement treatment on geotechnical properties of some washington state soils. engineering geology 104 (2009) 119–125 gillott, j. e., 1968.clay in engineering geology. elsevier published company, amsterdam gromko, j.g., (1974), “expansive soils”, journal of the geotechnical engineering deviator vol. 100, pp. 666-687. gulsah yesilbas, 2004. stabilisation of expansive soils using aggregate, waste, rock powder and lime. retrieved apr 5 th , 2013 from: http://etd.lib.metu.edu.tr/upload/12604950/index.pdf. kehew, e.a., (1995), geology for engineers and environmental scientists, 2nd ed. prentice hall englewood cliffs, new jersey, pp. 295-3002. lo, s. r., and wardani, s. p. r. (2002). “strength and dilatancy of a stabilised by a cement and fly ash mixture.” canadian geotechnical journal, 39(1), 77-89. mitchell, j. k. (1976). “the properties of cement-stabilised soils.” proceeding of residential workshop on materials and methods for low cost road, rail, and reclamation works, 365-404, leura, australia, unisearch ltd. mowafy, y.m., bauer, g.e., and sakeb, f.h., (1985), “treatment of expansive soils: a laboratory study”, transportation research record 1032, pp. 34-39. portland cement association (2003). properties and uses of cement-modified soil. retrieved aug 25 th , 2013 from: http://www.recyclingroads.org/techdocs/is411.pdf sherwood. p.1993. soil stabilization with cement and lime. hmso, london sw8 5dt sherwood. p. t. , 1995. alternative materials in road construction. thomas telford services ltd, 1 heron quay, london e14 4jd http://etd.lib.metu.edu.tr/upload/12604950/index.pdf http://www.recyclingroads.org/techdocs/is411.pdf al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 428 uddin, k., balasubramaniam, a. s., and bergardo, d. t. (1997). “engineering behaviors of cement-treated bangkok soft clay.” geotechnical engineering journal, (28)1, 89-119. winterkorn, h. f. (1955). the science of soil stabilization. bull. highway res. board,108:1-24 western stabilization. retrieved apr 5 th , 2013 from: https://www.google.com/webhp?client=affmaxthon-newtab&channel=t2#hl=en&client=aff-maxthon-newtab&channel=t2&output=sear yucel guneya, dursun sarib, murat cetinc, and mustafa tuncana. (2007). impact of cyclic wetting–drying on swelling behavior of lime-stabilized soil. building and environment 42 (2007) 681–688 table 1: plasticity index for samples pure soil soil+2.5% cement soil+5% cement soil+10% cement soil+15% cement liquid limit 70 55 50 49 48 plastic limit 32 38 38 37 35 plasticity index 38 17 12 12 13 table 2: ratios of losing weight and reduction in length and diameter for pure soil samples no. 1 day 7 days 28 days weight length dia. weight length dia. weight length dia. 1 180.69 86.09 38.03 152.05 77.02 34.36 146.05 76.1 34.24 2 177.72 83.34 38.06 156.48 75.33 34.11 144.56 74.78 33.92 3 177.84 85.61 38.72 154.98 77.03 33.44 144.98 75.30 32.88 ratio of losing %= 30% table 3: ratios of losing weight and reduction in length and diameter for pure soil + 2.5% cement samples no. 1 day 7 days 28 days weight length dia. weight length dia. weight length dia. 1 181.70 84.69 38.89 173.75 82.65 37.43 170.10 81.22 38.19 2 184.41 85.59 38.72 179.24 83.81 38.39 171.80 83.20 38.13 3 181.29 84.93 38.50 177.39 83.22 38.14 171.56 82.87 38.10 ratio of volume losing %= 7% https://www.google.com/webhp?client=aff-maxthon-newtab&channel=t2#hl=en&client=aff-maxthon-newtab&channel=t2&output=sear https://www.google.com/webhp?client=aff-maxthon-newtab&channel=t2#hl=en&client=aff-maxthon-newtab&channel=t2&output=sear al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 429 table 4: ratios of losing weight and reduction in length and diameter for poor soil + 5% cement samples no. 1 day 7 days 28 days weight length dia. weight length dia. weight length dia. 1 182.30 85.16 38.55 173.78 84.81 38.43 173.57 84.38 38.16 2 181.57 85.07 38.55 174.23 84.81 38.32 173.77 84.08 38.20 3 183.86 86.34 38.50 176.29 85.78 38.04 175.54 85.06 37.92 ratio of volume losing % = 3% table 5: ratios of losing weight and reduction in length and diameter for pure soil + 10% cement samples no. 1 day 7 days 28 days weight length dia. weight length dia. weight length dia. 1 182.40 87.32 38.75 175.47 85.96 38.37 175.23 85.88 38.32 2 182.79 86.02 38.30 176.38 85.29 38.18 175.02 85.16 38.13 3 181.54 85.90 38.87 174.30 85.26 38.28 174.10 85.17 38.24 ratio of volume losing %= 5% table 6: ratios of losing weight and reduction in length and diameter for pure soil + 15% cement samples no. 1 day 7 days 28 days weight length dia. weight length dia. weight length dia. 1 187.81 85.90 38.66 180.67 84.65 38.40 180.23 84.54 38.20 2 186.47 85.87 38.76 180.56 84.81 38.38 180.27 84.65 38.30 3 186.07 85.45 38.82 180.45 84.22 38.22 181.03 84.03 38.10 ratio of volume losing %= 4% al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 430 figure (1): soil particle shape (craig, 2004 figure (2): soil layers when water is added (craig, 2004). figure (3): mixing soil with cement al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 431 figure (4): penetrometer and equipment for liquid limit experiment. figure (5): plastic limit experiment figure (6): samples covered with wet cloth al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 432 figure (7): sample weighted and dimensions taken figure (8): liquid, plastic limit and plasticity index for expansive soil with different amount of cement. figure (9): water content of pure soil 0 10 20 30 40 50 60 70 80 pure soil 2.5% cement 5% cement 10% cement 15% cement liquid limit plastic limit plasticity index y = 0.0027x + 0.1631 r² = 0.8836 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 w a te r co n te n t penetrometer reading liquid limit for pure soil al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 433 figure (10): water content of pure soil + 2.5% cement figure (11): water content of pure soil + 5% cement y = 0.001x + 0.3515 r² = 0.9882 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 50 100 150 200 250 w a te r co n te n t penetrometer reading liquid limit for pure soil + 2.5% cement y = 0.001x + 0.3008 r² = 0.9074 0.42 0.44 0.46 0.48 0.5 0.52 0 50 100 150 200 250 w a te r co n te n t penetrometer reading liquid limit for pure soil + 5% cement al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 434 figure (12): water content of pure soil + 10% cement figure (13): water content of pure soil + 15% cement y = 0.0002x + 0.4552 r² = 0.936 0.465 0.47 0.475 0.48 0.485 0.49 0.495 0.5 0.505 0 50 100 150 200 250 w a te r co n te n t penetrometer reading liquid limit for pure soil + 10% cement y = 0.0005x + 0.377 r² = 0.8776 0.42 0.44 0.46 0.48 0.5 0.52 0 50 100 150 200 250 300 350 w a te r co n te n t penetrometer reading liquid limit for pure soil + 15% cement 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 90 في السوق المحلية وأثره على البيئة. غازولين المتوفرالتحديد نسب الرصاص في ddrraarriiff4477@@yyaahhoooo..ccoommالبريد األلكتروني البريد األلكتروني ** أ.م. د. عارف محسن لفته الفتالويأ.م. د. عارف محسن لفته الفتالوي aallssaaffffaarr__22000055@@yyaahhoooo..ccoomm البريد األلكترونيالبريد األلكتروني ** م.م.نبراس محمد عبد الرسول عباسم.م.نبراس محمد عبد الرسول عباس جامعة بغداد جامعة بغداد ––حوث السوق وحماية المستهلك حوث السوق وحماية المستهلك مركز بمركز ب* * الخالصة : البيئة بوساطة النشاطات إلىكميات كبيرة من الرصاص تطلق أنليست غنية بالرصاص أال األرضيةالقشرة أنالرغم من ب بشكل كبير حيث يساهم حرق الغازولين في زيادة نسبة الرصاص في الجو ،البشرية وبالخصوص في العقود القليلة الماضية ) كمضافات لتحسين الرقم telثيل الرصاص (أ) ورابع tmlتستخدم مركبات الرصاص العضوية مثل رابع مثيل الرصاص ( فر احساب نسب الرصاص في الغازولين المتو إلىيهدف البحث ) ومانعة للفرقعة في محركات الغازولين لذلكon( وكتينياأل .داد وأثر تواجده على البيئةفي محطات تعبئة الوقود في مدينة بغ لستة في محطات تزويد الوقودمنتجات وقود الغازولين لمركبات البنزين المتوافر من ) أنموذجاً 11(تم سحب نماذج عددها جانب فيلخمسة األخرى اجانب الكرخ : محطة وقود العطيفية والحرية واللطيفية واليرموك ومالحويش وأم الطبول و فيمنها .مدينة بغداد محطة وقود الصليخ والزيوت النباتية والكمالية ومدينة الصدر والكيالني في الرصافة: tricaprylmethylمع ملح رباعي األمونيوم ( i2ة مع األيوديـن ـمركبات الرصاص األلكيليأستعمل في بحثنا تفاعل ammonium chloride (aliquat 336 ) مذابًا في المثيل أيسوبيوتيل كيتونmibk ثبات أيونات زيادة ) لغرض رسم منحني المعايرة القياسي للرصاص . تمaasمطياف األمتصاص الذري بتقنية الرصاص في محلول النماذج عند فحصها مركبات الرصاص األلكيليـة الكلية في الغازولين.ل مستوى التركيزمعادلة منحني المعايرة القياسي حسب ب وباألستعانة نات يقترب محتوى الرصاص األلكيلي فيها من حدود تركيز الرصاص األلكيلي في الغازولين الخالي من بعض العيفوجدنا أن ملغم/لتر ( من مصادر بحثنا ) والبعض اآلخر دون هذا المستوى. بينما أعلى تركيز في العينات التي 7الرصاص أي من قيمة ث الغازولين من أضافات سابقة. حيث أن مصادر بحثنا أخضعت للفحص تشير إلى أن مستوى التركيز يقترب من حدود تلو ملغم/لتر لغرض رفع أداء منتوج الغازولين. 500أيضًا تشير إلى أنه من الواجب إضافة تركيز للرصاص األلكيلي يقارب ى تركيز يبلغ ملغم/لتر وأعل 0.17وجدنا من بين محطات تزويد وقود الغازولين أن أوطأ مستوى تركيز للرصاص يبلغ ففي بحثنا محركات وهذه نسب دون المستوي الطبيعي لغرض رفع أداء منتوج الغازولين إلى مستوى أعلى تجاه .ملغم/لتر 43.69 .الغازولين . ياألمتصاص الذر التقدير بتقنية الكلية، وقود الغازولين، مركبات البنزين، األلكيلية مركبات الرصاصالكلمات المفتاحية: 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 91 limitation of lead concentration in gasoline that available in the local market and its effect on the environment. dr. arif mohsin lafta alfatlawi * eemmaaiill :: ddrraarriiff4477@@yyaahhoooo..ccoomm nibras mohammed abdul alrasool abas * eemmaaiill :: aallssaaffffaarr__22000055@@yyaahhoooo..ccoomm * market research center and consumer protection -university of baghdad. abstract although the earth crust is not rich with lead element but large quantities have been released into environment as a result of humanity activities in particular through the last decades. consumption of gasoline plays a rule in increasing the concentration levels in the atmosphere in radical change, that cease of using fuel type leaded gasoline in vehicles such as tetraethyl lead (tel) and tetramethyl lead (tml) to improve the octane number and as an inhibitor to knocking phenomenon that happened in gasoline engines. our research aimed to determine concentration levels of lead in gasoline available in the local gasoline stations in baghdad city and its impact on the environment. eleven gasoline samples were gathered from gasoline stations spreading in baghdad city. six of which in karkh site: al-autaifaih, al-hurai, al-latifaih, al-yarmook, mulla-howaish, and umo-altobule gasoline stations. and other five in rusafa site: al-solaikh, vegetable oils, alkamalai, al-saadre city, and al-kailany gasoline stations. in this research the reaction of alkyl lead compound with solution of tricaprylmethyl ammonium chloride ( aliquat 336 ) and iodine i2 that dissolved in isobutyl ketone (mibk) have been used to increase the stability of lead ions in the samples solutions that were subjected to tests using atomic absorption (aas) technique. standard calibration curve for lead has been drawn, so by using the rectilinear equation for the given standard curve the level of total alkyl lead in gasoline samples was estimated. by this work it was found that the content of alkyl lead in some gasoline samples approaches the 7 mg/l or the gasoline lead free ( references of this research ) and other samples below this range, whereas the higher concentration in samples that were subjected to test have been denoted to pollution to the gasoline was occurred from previous additions. our research references also denoted that concentration of 500 mg/l of alkyl lead must be added to the gasoline fuel in order to increase its performance. using the procedure that has been used in our work the minimum level of alkyl lead in gasoline samples was found equal to 0.17 mg/l and the maximum value of alkyl lead was found equal to 43.69 mg/l. these levels of alkyl lead found in our research are below the natural additions that give higher performance of gasoline product toward vehicles of gasoline engines. key words: total alkyl lead, gasoline vehicle, determination using atomic absorption. 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 92 المقدمة في وقود الغازولين لمحركات البنزين مصاعب بسبب أن مركبات الرصاص واجهت طرق تحليل الرصاص مركبات أو الخليط من tmlورابع مثيل الرصاص telرابع أثيل الرصاص األلكيلية المختلفة مثل في ب الرصاصطريقة حسا طبقتف ،تنتج أستجابات مختلفة ألنها في الغازولين malالرصاص األلكيلية تخفيف والتي شملت ) robinson, 1961(ألول مرة aas طة مطياف األمتصاص الذرياالغازولين بوس مع absorbanceاألمتصاصية ةقارنمو aasتقنية بقبل أخضاعها للفحص isooctaneاأليسوأوكتان بالعينة المثيل أثيل كيتون مذيبدم أستخف، مذابة في األيسوأوكتان telكميات معلومة من رابع أثيل الرصاص mek )dagnall and west 1964 ( عينة الغازولين مع أستخدام نترات الرصاص لتخفيفpb(no3)2 . ) trent, 1965( عاليةهذه الطريقة دقة وحققت كمادة قياسية ،mibkتون كي أيسوبيوتيلمذابًا في المثيل i2األيوديـن أضيف ألول مرة ) kashiki et al, 1971(لكن methyl isobutyl ketone األيوديـن تؤدي أضافة ة،ـالغازولين قبل أخضاعها للفحص بهذه التقنيإلى عينات i2 ودو ألكيلية ـإلى تكوين أيونات اآليiodoalkyl anions ة ـالثباتي والتي تبلغstabilized ة ـعندما تتبعها أضاف ه ـيغتـصو tricaprylmethyl ammonium chlorideأي aliquat 336ملح رباعي األمونيوم محلول تفاعل يضمن أستجابة متماثلة إلى جميـع مركبات الرصاص ليحدث ch3n[(ch2)7ch3]3clالكيـميـاويـة .) lowry et al, 1982(و ) jungers et al, 1975) و( andrew, 2010(األلكيلية في النموذج astmمن قبل الجمعية األمريكية لفحص المواد ولين طريقة حساب الرصاص في الغاز ال هذه تم أقرار )astm, 1973 ( لحماية البيئة ةكطريقة قياسية في التحليل وتم أقرارها أيضًا من قبل الوكالة األمريكيepa )federal register , 1974 ( . وتتضمن الطريقة إجراء تفاعل مسبق مع مركبات الرصاص األلكيلية في وبلوغ األستقرار لناتج التفاعل من معقدات يوديد الرصاص األلكيلية بإضافة رباعي i2دين مع األيو الغازولين .aliquat 336األمونيوم مطياف تقنية حساب الرصاص في الغازولين مثل أستخدامفي تقنيات تحليلية مختلفة تمأستخدذلك فضًال عن colorimetryس تحديد األلوان الكولومتري تقنية مقيا، و ) xrf )astm, 1981األشعة السينية المتفلور )astm, 1985 ( وتقنية التحليل الحجمي الكمي ،volumetry )astm, 1982 d2547 ( وتقنية ، قيد التطبيق التقنيةإضافة إلى أستخدام ) titrimetry )astm, 1982 d3116المعايرة بالتحليل الحجمي aas )kashiki et al, 1971 ( و)astm, 1984 (. 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 93 مضافات 4هيدروكاربونات و 9من المركبات الكيميائية منها 13يحتوي على {بنزين السيارات} والغازولين )jungers et al, 1975 ( الخطرة الكيميائية من المواد هاجميع دوتع)hosseinpour et al, 2010 (. على و وصفاتها متشابه رية أحادية الحلقة مركبات عط 6ية في الغازولين هي ـالهيدروكاربونات المهمة والرئيسو -والميتا -والبارا -البنزين والتلوين واألثيل بنزين واألرثو وتشمل btexب ويطلق عليها تسمية عامه ـوجه التقري لمركبات الرصاص البديـلة المواد أحد , mtbe (ch3)3coch3ثالثي بيوتيل مثيل أيثر ويعد كزالينات. .) astm, 1982 d2547(ها ـالوظيفة نفسة التي تؤدي ـاأللكيلي هدف البحث جانبي الكرخ فر في محطات تزويد الوقود فيايهدف هذا البحث إلى حساب نسب الرصاص في الغازولين المتو مدينة بغداد. والرصافة من الجزء العملي في تحليل الرصاص في الغازولين: المستخدمةالمواد والمحاليل riedeldehaen ag sleaze hannover من شركة ( mibk 99%وتيل كيتـون مثيـل أيزوبي -1 company. ( ) scharlab s.l. spain company ركةـمن شأيضًا ( benzene exra pureبـنزين -2 riedel dehaen ag sleaze hannoverركةـمن ش( isooctane %99.9ثالثي مثيـل بـنتان -3 company ( ) thomas baker, india company من شركة ( %99.9ات الرصاص نتر -4 محلول i2األيوديـن من وحضر ) gcc england company ركةـمن ش ( %99.9األيوديـن بلورات -5 مل من 40في i2األيوديـن غم من بلورات 3بإذابة benzene) في البنزيـن w/v( وزن إلى حجم 3% البنزيـن أيضًا.ويخفف إلى العالمة ب مل 100حلول إلى قنينة حجمية سعة وينقل الم benzeneالبنزيـن himedia registed trademark gmbh ركةـمن ش ( aliquat 336ملح رباعي األمونيوم -6 company ( mibk) في الكيتون v/v( حجم إلى حجم %1بتركيز aliquat 336ملح رباعي األمونيوم من محلول -7 في الكيتون أيضًا ) v/v(حجم إلى حجم % 10بتركيز أيضًا aliquat 336اعي األمونيوم محلول ملح ربو mibk. 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 94 تحضير األنموذج: ,astm(و ) kashiki et al, 1971({ مصادر بحثنا بأستخدام هذه الطريقة هي: يسمح في هذه الطريقة ) lowry et al, 1982(و )jungers et al, 1975(و )federal register , 1974(و )1973 لمركبات الرصاص األلكيلية في العينات بأن تبلغ الثباتية بوساطة } )andrew, 2010(و )astm, 1984(و ، وبتفاعل كل mibkمذابة في الكيتون aliquat 336ومع ملح رباعي األمونيوم i2تفاعلها مع األيودين ثم بتفاعلها مع ملح benzene) في البنزين w/v( وزن إلى حجم %3بتركيز i2األيودين نموذج مع محلول .mibk) في الكيتون v/v( حجم إلى حجم %1بتركيز aliquat 336رباعي األمونيوم عينة الغازولين للتحليل: تحضير بواسطة أسطوانة مدرجة. mibkمل من الكيتون 30مل حوالي 50أوًال: توضع في قنينة حجمية سعة مل بواسطة الماصة من عينة الغازولين وترج القنينة جيدًا. 5 حجميةالة قنينيضاف إلى ال :ثانيًا◌ً ) في w/v(وزن إلى حجم % 3بتركيز i2األيوديـن محـلول من مل 0.1يضاف إلى القنينة الحجمية :ثالثاً ويسمح للخليط أن يتفاعل حوالي دقيقة واحدة. benzeneالبنزيـن % 1بتركيز aliquat 336محلول ملح األمونيوم ل بواسطة الماصة منم 5رابعأ: يضاف إلى القنينة الحجمية ترج القنينة جيدًا مرًة أخرى.ثم mibk) في الكيتون v/v(حجم إلى حجم عينة الغازولين الخالي من الرصاص للتحليل: تحضير الخالي من كبديل للغازولين trimethyl pentaneثالثي مثيـل بنتان isooctaneيستخدم األيسوأوكتان . ) trent, 1965(و ) dagnall, 1964( الرصاص بواسطة أسطوانة مدرجة ويضاف إلى mibkمل من الكيتون 30مل حوالي 50توضع في قنينة حجمية سعة وترج الغازولين الخالي من الرصاص isooctaneثالثي مثيـل بـنتان مل بواسطة الماصة من 5 حجميةالقنينة ال عينة الغازولين. عأ في فقرة تحضيرثم تتبع الخطوات ثالثًا وراب القنينة جيداً تحضير المحاليل القياسية: للرصاص: األساس أوًال : تحضير المحلول القياسي تساوي pb(no3)2إلى وزن صيغة جزيئة نترات الرصاص pbألن نسبة وزن صيغة ذرة الرصاص ملغم/لتر مذابًا في حجم واحد لتر 1000بتركيز pbمحلول قياسي أسـاس للرصاص فلتحضير 0.6256 .pb(no3)2غم من نترات الرصاص 1.599يتطلب وزن غم من 0.3998ملغم/لتر بإذابة 1000بتركيز pbر محلول قياسي أسـاس للرصاص يحضتم ت فعلى ذلك 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 95 aliquatونيوم ملح رباعي األم% من 10محلول مل من 200النقية في pb(no3)2نترات الرصاص قنينة في بالمحلول نفسه إلى العالمةالحجم ويكمل mibkفي الكيتون ) v/v(حجم إلى حجم 336 وفي ويحفظ اللون معتمة زجاجية قنينة إلىالمحلول القياسي ويرج جيدًا ثم ينقل مل 250 حجمية سعة الثالجة. -ثانيًا : تحضير محاليل قياسية ثانوية للرصاص: pbللرصاص ملغم/لتر 1000المحلول القياسي األســاس من محاليل قياسية ثانوية للرصاصتحضر بواسطة الماصة إلى قناني على التوالي مل) 2 ، 1 ، 0.5 ، 0.2 ، 0.1(وذلك بنقل حجومًا بتركيز aliquatمل إلى كل منها من محلول ملح رباعي األمونيوم 5مل وأضافة 100حجمية سعة كل منها وتخفف المحاليل في كل قنينة حجمية إلى mibk) في الكيتون v/v( حجم إلى حجم %1بتركيز 336 5 ، 2، 1محاليل قياسية ثانوية للرصاص بتركيز للحصول على mibkالعالمة بواسطة مذيب الكيتون .على التواليملغم/لتر 20 ، 10 ، النتائج والمناقشة : مركبـات الرصـاص األلكيليــة فـي حسـاب i2األيوديــن و aliquat 336ألمونيـوم أستعمل ربـاعي ا هذا البحثفي ثالثـــي مثيــــل بنتـــان كبـــديل و وأوكتان األيســـوأســـتعمل مطيـــاف األمتصـــاص الـــذري باســـتخدامالكليـــة فـــي الغـــازولين للغازولين الخالي من الرصاص. ، 2، 1تركيز ضد ياسية ثانوية للرصاص رسم األمتصاص لمحاليل قبطريقة منحني المعايرة القياسي باستخدامو ملغم/لتر ومحلول األيسوأوكتان الخالي من الرصاص. 20، 10، 5 ) 1(الجـــدول و )1(الشـــكل كمـــا فـــي بهـــذه الطريقـــة pbتـــم الحصـــول علـــى منحنـــي المعـــايرة القياســـي للرصـــاص ام برنـامج أحصـائي متقـدم كمـا فـي المعـايرة القياسـي بأسـتخدوالتقـاطع لمنحنـي معادلة الخـط المسـتقيممنه قت توأش المعادلة اآلتية: أيضــًا تعتبــر ppmوحــدة علمــًا أن . mg/lتمثــل التركيــز بوحــدة xتمثــل قــراءة األمتصــاص وأن yحيــث أن . من وحدات التركيز الشائعة طياف مبتقنية باألستعانة حساب نسب مركبات الرصاص األلكيليـة الكلية في الغازولينتم في بحثنا و أستيلين. -الذي يستخدم شعلة هواء aasاألمتصاص الذري mg/l in ionconcentrat x and n absorptio y where 1.0 rx 10 2.401 10 3.73 y 226== =×+×= 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 96 عينة في كلبوحدة ملغم/لتر pbالرصاص تم الحصول على قراءة تركيزبنظر األعتبار وبأخذ عامل التخفيف وباألستعانة مدينة بغداد من لرصافةالكرخ وافي جانبي محطات الوقود من نماذج الغازولين المسحوبة من يبين القراءات الفعلية للتركيز لكل عينة مقابل قراءة األمتصاص. )2لجدول (فاالمعايرة القياسي منحنيب أن أوطــأ مســتوى تركيــز للرصــاص مــن بــين محطــات تزويــد وقــود الغــازولين قيــد )2) وشــكل (2جــدول (يبــين أن ملغم/لتر. 43.69ملغم/لتر وأعلى تركيز يبلغ 0.17البحث يبلغ من الواجب إضافة وأنغرض إضافة الرصاص األلكيلي هو لزيادة أداء منتوج الغازولين إنير مصادر بحثنا تش . بينمــا ) hosseinpour et al, 2010( ملغم/لتــر 500علــى األقــل حــدود تركيــز الرصــاص األلكيلــي يقــارب تشـير إلـى أو ي مـن الرصـاصملغم/لتـر فـي الغـازولين الخـال 7يقترب مستوى تركيز الرصاص األلكيلي من قيمة ) kashiki et al, 1971( يقتــرب مـــن حـــدود تلــوث الغـــازولين مـــن أضــافات ســـابقة الـــذي مســتوى التركيـــز ومـن .) andrew, 2010(و ) astm, 1984(و ) lowry et al, 1982(و ) jungers et al, 1975و( لرصـاص األلكيلـي فـي تشـير إلـى تذبـذب مسـتوى تركيـز ا )2) وشـكل (2جـدول ( مـا فـيهـذا البحـث كنتائج خالل جانب الرصافة.في خمسةجانب الكرخ مع ة منها في تالغازولين المجهز في محطات الوقود لس الرصاص األلكيلي فيها من حدود تركيز الرصاص األلكيلـي فـي الغـازولين الخـالي فبعض العينات يقترب محتوى إلـى مسـتوى التركيـز يـدل علـى ت يشـير وأعلـى تركيـز فـي العينـا من الرصاص والبعض اآلخر دون هـذا المسـتوى حدود تلوث الغازولين بالرصاص األلكيلي من أضافات سابقة. األستنتاج المتـــوفر فـــي محطـــات الوقـــود مـــن حيـــث األداء هـــي مترديـــة وال يرقـــى ليكـــون ن حالـــة منتـــوج الغـــازولين الحـــالي إ إلـى تضـرر محركـات المركبـات أو ممـا يـؤدي ) hosseinpour et al, 2010( ذو مستوى أداء عـالي غازولين .تضرر أقتصادي كبير أضرار الرصاص على البيئة ) russel and stephens, 983( تطلق إلى البيئة بواسطة النشـاطات البشـرية التي الرصاصوجد أن كميات مثــل الغــرض مــن أسـتخدام مركبــات الرصــاصومـن المعلــوم أن الصــحة البشــرية. لهـا تــأثيرات مضــرة علـى البيئــة و فــي onلمنــع الفرقعــة وتحســين الــرقم األكتينــي هــو telورابــع أثيــل الرصــاص tmlربــاعي مثيــل الرصــاص . لكن حرق الغازولين بواسطة مركبـات الغـازولين فـأن هـذه ) hosseinpour et al, 2010(محركات الغازولين .الطرق السريعة والداخلية األضافات تحدث ضررًا كبيرًا على البيئة وعلى صحة المستهلك وعلى مستخدمي التوصيات 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 97 ذو األداء العالي المعامل بوحدات األزمرة ويمنع أضافات الرصاص الغازوليننوصي بأستيراد أو أنتاج لهذا -1 حفاظًا على سالمة البيئة والمستهلك.للغازولين األلكيلي راد.جديدة لالستي آليةالحد من استيراد المركبات بشكل عشوائي ووضع -2 references american society for testing & materials astm method d 2337 part 17 ,1973, (astm, 1916 race street, philadelphia, pennsylvania usa) . american society for testing & materials astm, "standard test method for lead in gasoline by x-ray spectroscopy", 1981 ,method d 2599. american society for testing & materials astm "standard method for testing rapid field test for trace lead in unleaded gasoline (colorimetric method)" 1985 method d 3348. american society for testing & materials astm "standard test method for lead in gasoline, volumetric chromate method",1982 , method d 2547. american society for testing & materials astm "standard test method for trace amounts of lead in gasoline",1982 , method d 3116. american society for testing & materials astm "standard test method for lead in gasoline by atomic absorption spectrometry",1984 , method d 3237-97. andrew r. " determination of lead in unleaded gasoline on the liberty series ii icpoes with axially-viewed plasma" application note, agilent technologies, inc. printed in the usa ,2010, icpes-22. dagnall, r.m. and west, t.s. talanta ,1964 ,11:1553. federal register, 1974, 15449. hosseinpour m.a., ghoreishi h., gitipour s., and safarnejad m. "investigation of oil inside the wells in rey area in tehran oil refining company in iran" world academy of science engineering and technology ,2010 , 69:200-206. jungers r.h., lee jr. r.e. , and von lehmden d.j. "the epa national fuels surveillance network i. trace constituents in gasoline and commercial gasoline fuel additives" environmental health perspectives,1975, 10:145-150. 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 98 kashiki, m., yamazoe, s., and oshima, s., " determination of lead in gasoline by atomic absorption spectroscopy" anal. chimica acta ,1971, 53:95-100. lowry j.h., meszaros t.j., and conlon l. "automated atomic absorption determination of lead in gasoline" journal of automatic chemistry ,1982, 4(3):112115. robinson, j.w. anal. chim. acta., 1961, 24:451. russel r.r., stephens r. "lead versus health science and effects of low level exposure" eds. rutter m. and jones r.r. , 1983 , john wiley & sons :141-177. trent, d.j. {perkin elmer co. } at. abs. newsletter ,1965 , 4(9):348. 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 99 وبين بجهاز األمتصاص الذري pbالثانوية للرصاص سية البيانات من تحليل المحاليل القيا ): 1( جدول .واألمتصاص المطابق له) isooctaneفي أيسوأكتان ( pbلرصاص تركيز االصف األول فيه the actual concentration of lead pb mg/lin solution the accordant absorbance to actual concentration 0.0002 0.008 1.5866 0.0381 7.2542 0.1742 11.1603 0.2680 18.8976 0.4538 ملغم/لتر مع األمتصاص بتقنية األمتصاص الذري في كل عينة من pb ) التركيز النهائي للرصاص 2جدول ( ) محطة من محطات الوقود في جانبي الكرخ والرصافة من 11نماذج الغازولين المسحوبة من ( مدينة بغداد no. sample* absorbance concentration of lead pb mg/lin gasoline samples 1 a 0.1049 43.69 2 b 0.0744 30.99 3 c 0.0732 30.49 4 d 0.0004 0.17 5 e 0.0202 8.41 6 f 0.0017 0.71 7 g 0.0175 7.29 8 h 0.0032 1.33 9 k 0.0011 0.46 10 l 0.0690 28.74 11 m 0.0336 13.99 gومدينة الصدر: fواللطيفية : eوالكمالية: dوالزيوت النباتية: c الصليخ:و bوالحرية: a: العطيفية: محطة وقودالحظة: *م 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 100 . mوأم الطبول: lوالكيالني: k: ومالحويش hواليرموك : 18.8976, 0.4538 11.1603, 0.268 7.2542, 0.1742 1.5866, 0.0381 0.008, 0.0002 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0 5 10 15 20 actual concentration of pb mg/l a bs or ba nc e .pbالثانوية للرصاص لمحاليل القياسية ) منحني المعايرة القياسي ل 1 شكل ( 2013 لسنة -ابعلرا العدد السادس المجلد ةالهندسي للعلوم القادسيه مجلة 101 30.99 0.17 8.41 0.71 7.29 1.33 0.46 28.74 13.99 43.69 30.49 0 5 10 15 20 25 30 35 40 45 50 العطيفية a b الحرية الصليخ c الزيوت النباتية d الكمالية e اللطيفية f مدينة g الصدر اليرموك h مالحويش k الكيالني l أم الطبول m fuel station in bgd city c on ce nt ra tio n of p b m g/ l ) مستوى تركيز الرصاص األلكيلي في العينات التي جمعت من محطات 2 شكل ( في جانبي الكرخ والرصافة من مدينة بغداد.الوقود تحديد نسب الرصاص في الغازولين المتوفر في السوق المحلية وأثره على البيئة. الخلاصة : المقدمة النتائج والمناقشة : al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 effect of changing packing shapes on the evaporation rates using different combination arrangements of dry-wet cooling towers systems lect.dr. nagam obaid kariem iraq-baghdad bab/al-muthem al-mustansiryah university/college of engineering nagam75@yahoo.com abstract the aim of this study is reduce the evaporation rate from dry-wet cooling tower combination system through using different shapes and different arrangements between dry and wet cooling towers. four shapes of corrugated packing were used in the study with all arrangements combination between dry and wet cooling towers in order to get the shape that give minimum evaporation rate (loss). four arrangements combination of dry-wet cooling tower, two of arrangement were series (as1, and as2), and two of arrangements were parallel (ap1, andap2). the variables for this study were obtained from north oil company (n.o.c.) in the ministry of oil of iraq; these data included temperatures, flow rate, packing types, ambient conditions, pressure, and fan parameters. the results show that as1 configuration produces lower evaporation rates by about 58 % reducing in percent, and then followed by the other configuration. the corrugated types 1 and 4 gives the minimum amount of evaporation losses then the other types of corrugated by about 40 %. the corrugated types 1 and 4 operated with a minimum cost of operation. keyword: cooling, wet, dry, corrugated, evaporation rate, and combination الخالصة الرطبة و ذلك من خالل استعمال اشكال مختلفة -الغرض من البحث تقليل معدل التبخر من منظومة ابراج التبريد الجافة الرطبة.-من الحشوات المتموجة و كذلك من خالل الربط المختلف بين ابراج التبريد الجافة ة لهذه الدراسة مع مختلف انواع الربط بين ابراج التبريد الجافة و تم استعمال اربعة اشكال مختلفة من الحشوات المتموج al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 233 الرطبة وذلك لغرض الحصول على الشكل المتموج الذي يعطي اقل معدل تبخير)فقدان(. (.ap1,ap2( و ربطين على التوازي )as1,as2تضمن الربط بين االبراج الجافة و الرطبة ,ربطين على التوالي ) غيرات لهذه الدراسة بمعطيات من شركة نفط الجنوب العائدة لوزارة النفط العراقية و شملت هذه المتغيرات كل من المت الحرارة و نعدل الجريان و شكل الحشوات و الظروف الجوية والضغط و معامالت المروحة. % و ثم يليه باقي انواع 04بريد و ذلك بمعدل ينتج اقل معدل فقدان تبخيرمن ابراج الت as1 بينت النتائج ان الربط % عن باقي 04تعطي اقل معدالت فقدان تبخير بمقدار 0و رقم 1الربط االخرى.بينت النتائج ان االشكال المتموجة رقم يعمالن باقل كلفة تشغلية لالبراج . 0و 1انواع االخرى من االشكال المتموجة,كذلك لوحظ ان الشكلين المتموجين nomenclature a area of air-cooled heat exchanger(m 2 ) unit cost of air cooled heat exchanger($/unit area) qtower the heat load on the tower wevap. the evaporation rate wcirc the water circulation rate(t/h) hfg latent heat of vaporization (btu/lbm); ~1000 btu/lbm flatent fraction of total heat rejected by latent heat transfer. cp specific heat btu/lb-ºf t temperature ºc outlet dry bulb temperature o c tref. reference temperature o c capital cost of cooling tower, $/year fin cooling system inlet water flow rate (t/h)rt range (ºc), (th-tc) at approach (ºc), (tc-twb) pp pumping power mair mass air flow rate (t/h) m make up rate (t/h) ntu number of transfer units b blow down rate (t/h) u overall heat transfer coefficient in dry cooling(btu/hr. o f.ft 2 ) h humidity of air al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 specifi heat λ latent heat of evaporation subscripts w water a air c cold h hot introduction [ shan,2000, and ashrae handbook 1995], considering the fact that the wet cooling tower was a steady flow device that uses a combination of mass and energy transfer to cool water by exposing it as an extended surface to the atmosphere. the water surface was extended by filling, which presents a film surface or creates droplets. the airflow may be cross flow or counter flow and caused by mechanical means, convection currents or by natural wind. [ ala, 2002] said that in mechanical draft towers, air is moved by mechanically driven fans to provide a constant air flow. [ gao, 2009] recorded that the wet cooling towers were considered the ultimate water conservation machine providing the amount of water needed to replace evaporation and other losses. [ qi and liu, 2008] refer to that in wet cooling the major two way of loosing water are evaporation and blow-down .the benefit of blow-down is to prevent the scaling due to increase the amounts of dissolved solids to the point where they began to precipitates. [ sarker, 2008] considering the fact that the combination of dry and wet cooling tower provide as a good way to reduce evaporation. there are many advantages for the combination of wet cooling and dry cooling, the first was reducing the make-up water consumption ,second reducing the plumes emitted from the cooling tower(avoiding environmental impact), and third reducing the cost of operation, finally increasing the variety of material that using for construction of cooling tower. [ gardner, 1975] studied the performance and economic design on different configurations based on operation parameters, the variable that this search take in account were the height of packing, types of tubes, velocity, and air conditions. marcel, 1984 studied the combination of dry and wet cooling tower, and they found that the wet-dry cooling tower can be constructed either as separated dry and wet towers. [ nakkash, 1994] studied the effects of different variables (water to airflow ratio, humidity, and temperatures) on the amounts of evaporation rates. [ gan and riffat, 1999] have been developed computer models to study the thermodynamic and al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 economic performance of various types of combination dry-wet cooling towers. these models consider the basic thermodynamics of wet and dry heat transfer, steam turbines, and condensers, the influence of different power loading patterns and changing meteorological conditions, and the various economic parameters. [ hossein, 2011] used the cooling water system of tabriz refinery as a case study. for this purpose, a data collected from weather meteorological organization and process cooling water system of the refinery in a one-year period were collected. the methods in this paper, studied the conditions of dry cooling tower replacement instead of wet rather than a general or conditions and different scenarios, with analysis advantages and disadvantages of each mode and compare the technical and economic methods to achieve an optimal state of proposed economic and will. dutta, 2007 considering the fact that in dry cooling towers circulatory cooling water temperature lower than the temperature of the bubble is not possible; with recognizing losses in water systems, cooling tower replacement conditions dry instead of wet cooling tower more general, or at least part of the year will examine. an economical method to determine the replacement cost, which includes replacement (the cost of construction, installation and commissioning of dry cooling tower, pumps and related pump and fan electricity costs) cost of water is decreased due to compensatory replacement of whole or part year and compared in terms of replacement cost less than compensatory cost savings by water, the alternative methods will used. the aim of this research was to reduce the evaporation rate (loss) from dry-wet cooling tower combination system through using different shapes and different arrangements combination between dry and wet cooling towers. four shapes of corrugated packing were used in the study with all arrangements between dry and wet cooling towers in order to get the shape that give minimum evaporation rate. experimental procedures in this work, different ways used to reducing the evaporation rate by connection dry with wet cooling towers, and in this work one can show the effects of changing the power of fan and the indirect surface area in dry cooling towers. four arrangements of dry-wet cooling tower used in this search, two of arrangement were series (as1, and as2), and two of arrangements were parallel (ap1, andap2)(figures(1.a, 1.b, 2.a, and2.b)). in parallel arrangements the humidity of the exit air from wet tower must be estimate (equation (1) (marcel, 1984)) and the humidity inlet equal the humidity outlet, the wet bulb temperature can estimated by trial and error. in series arrangements, only one fan was provided for each dry-wet cooling system. (1) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 for configuration represented in figure (2.a), where air and water come contact first in dry sections then in wet section. one can notice that dry bulb temperature entering to the dry section equal to the dry bulb temperature exiting from the wet section. the configuration in figure (2.b), where air and water coming contact first in wet sections first then in dry section. one can notice that dry bulb temperature entering to the dry section equal to the dry bulb temperature exiting from the dry section. the performance of cooling tower for wet and dry cooling towers ,evaporation rate for wet cooling tower, air rates for dry cooling tower, surface area of dry cooling tower, cost cooling tower, and water to air flow in wet cooling tower were estimated for each types of corrugated cooling tower and combination of wet-dry cooling tower. the wet bulb temperature, dry bulb temp., humidity, and relative humidity with different height were considered for cooling tower. in dry cooling tower the fins were made of aluminum while the tubes made of copper, the space of tubes had the shape of triangular pitch in order to increase the heat transfer between fluids. four types of corrugated packing were used with all combinations between dry and wet cooling towers in order to get the shape that give minimum evaporation rate (loss). the corrugated shape gave as maximum transfer of mass and heat transfer due to the good contacts between water and air in wet cooling tower, also it is so simple to make maintained or repaired it. the material of packing were made of from poly vinyl chloride, the poly vinyl chloride prevents bio-growth in the surface of packing, the dimensions of the four types (shapes) of corrugated packing can be noticed in table(1) . mathematical calculations the basic function of a wet cooling tower (fig. 3) is to cool water by intimately mixing it with air. this cooling was accomplished by a combination of sensible heat transfer between the air and the water and the evaporation of a small portion of the water. this type of transfer is represented by equation(2),[ dutta, 2007]; (2) this equation is commonly referred to as the merkel equation. the left-hand side of this equation is called the "tower characteristic," which indicates the 'degree of difficulty to cool' the water or the 'performance demand' of the tower. the driving force depending on the difference between the temperature and enthalpy of the saturated air. the tower characteristic (kav/l), can be calculated through the merkel equation[marcel, 1984]. (3) the fill height (fh), depends on the fill characteristic and l/g, and is computed by equation (3): where ‘c’ and ‘n’ are constants, which depend on the tower, fill. these both factors are determined through fill test. the constants for equation (3) for the case of corrugated al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 packing are listed in table (2). the rate of evaporation of water from the tower is related to the heat load on the tower, qtower, and determined by he following equations. qtower = wcirc . cp . (th – tc) (4) with the evaporation rate given by wevap = qtower . (flatent/hfg) (5) the percentage reduction in evaporation rate gives very important indication about the benefit of combined system because it takes account the evaporation losses when just wet cooling tower is used, this percentage can be expressed in equation(6); (6) in design targeting, the objective is to minimize the total annual cost (kim et al., 2001). consequently, the defined objective function of the introduced design methodology was to determine total annual cost of the cooling tower including operational and capital cost (kaiser et al., 2005). the capital cost of cooling tower is as follows: (7) as shown in equation (7), the capital cost in $/y, including chemical engineering index and annualisation factor, a function of water flow rate in t/h. the approach, range and wet bulb temperature are in ºc. the operating cost of cooling tower: pumping cost + fan cost + make-up cost + chemical treatment cost + blow-down treatment cost. (8) the total annual cost (tc) could be state as follows. the operating cost and capital cost of the cooling tower differently affect the overall cost of cooling water systems, as shown in equation(9). tc = cc + oc (9) the dry cooling tower (heat exchanger), where the water was flowing inside tubes and air was flowing outside the tubes. the heat transfer was determining by the logarithmic mean temperature between the air and water(hans d.b. & karl s.(2006)). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 (10) the capital cast of dry cooling tower was written as follows; (11) the annual cost could for dry cooling equal to the summation of operation cost plus the capital cost as listed in equation (12), so the total annual cost for dry-wet (tct) cooling tower can be shown in equation (13). (12) (13) a computer program was written by visual basic program to calculate and optimize the combination arrangements in cooling system. results & discussion the study for reducing evaporation rates was done by using four combination arrangements, two arrangements as series and two arrangements as parallel (as1, as2, ap1, andap2). the ability of reducing evaporation rate in cooling towers using different shapes of corrugated packing and combination between dry and wet cooling tower was studied. four packing shapes of corrugated packing are take for each the four arrangements. the results show that for short height of packing the evaporation rate would be at minimum value and minimum cooling tower cost, this is because the short height mean short time of contact between air and water (reducing mass transfer of water vapor) as cleared in table(3) . the effect of water to air ratio on the performance of cooling tower and design of combined dry-wet cooling tower shows that increasing the ratio, and the height of packing increase depends on the type of corrugated packing and as the air flow decrease the pressure drop increases, thus the evaporation losses decreases, as shown in (figures 4,5,and 6) and listed in table(4). the evaporation loss is affected by the connection arrangements according to the change position of cooling tower due to the change in the temperature and humidity according to equation (5), as shown in table (5). in table (6), the results prove that as the outlet water temperature from dry part increases, the area of dry part decreases and the airflow rate decreases. this because of the decrease in heat load .the cost decreases due to the decrease in area of dry part. the results show that the configuration as1 gives a higher evaporation percentage al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 232 reduction and lower total annual cost as a comparing with the other configuration arrangements (as2,ap1, andap2),as shown in figures(7,8).while the other types of configuration operated with high total annual cost. the corrugated types 1 and 4 gives the minimum amount of evaporation rates then the other types of corrugated. the corrugated types 1 and 4 operated with a minimum cost of operation (fig. 9). conclusion from the study, it can be concluded that the percent of reduction in the evaporation and the cost gives a good indication about the benefit of combination arrangements systems. the shape of the corrugated packing affecting on the amount of evaporation also, the height of packing related with the amount of evaporation retrogradly. the configuration as1 gives a higher evaporation percentage reduction and lower total annual cost as a comparing with the other configuration arrangements (as2,ap1, andap2),while the other types of configuration operated with high total annual cost. references 1. ashrae handbook 1995, hvac applications, ashrae inc., atlanta, ga. 2. ala h.(2002), theoretical and computational analysis of closed wet cooling towers and its applications in cooling of buildings. energy and buildings 34-477. 3. dutta, b.k., (2007). principles of mass transfer and separation processes. phi learning private limited, 1st ed. 4. gao, m., et al., (2009). performance prediction of wet cooling tower using artificial neural network under cross-wind conditions. international j. thermal sci., 48(3): 583589. 5. gan g,and riffat s.(1999),numerical simulation of closed wet cooling towers for chilled systems,applid thermal engineering 19-12. 6. gardner b.(1975), work on advanced cooling tower system. international symposium on the cooling systems, london. 7. hans d. b. & karl s.n(2006), heat and mass transfer, second edition. 8. hossein zadeh hesas r.(2011), an economical comparative study of different methods for decrease cooling towers makeup cost in oil refineries. world applied sciences journal 12 (7): 988-998, 2011. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 9. kaiser, a. s.; lucas, m.; viedma, a.; zamora, b., (2005).numerical model of evaporative cooling processes in a new type of cooling tower, int. j. heat mass tran., 48 (5), 986-999. 10. marcel r.(1984).reducing water consumption in cooling towers. cep ,july. 11. nakkash n(1994).the reduction in water consumption in cooling towers. engineering and tech. ,july. 12. nagam o.k.(2002),performance of cooling tower, thesis submitted to the college of eng.-university of baghdad. 13. qi, x. and z. liu, (2008). further investigation on the performance of a shower cooling tower. energy conversion and management, 49(4): 570-577. 14. sarker, m.m.a., et al., (2008). performance characteristics of the hybrid closed circuit cooling tower. energy and buildings, 40(8): 1529-1535. 15. shan k(2000), handbook of air conditioning and refrigeration. second edition. table(1):types of corrugated packing type of corrugated surface pitch of packing(mm) distance between the packing(mm) type1 rough 50 40 type2 rough 45 40 type3 smooth 40 30 type4 rough 40 25 table(2):the constants for equation (3) (nagam (2002)) height(cm) corrugated shape n 150 type 1 0.28 -0.44 140 type2 0.41 -0.58 120 type3 0.27 -0.75 100 type4 0.37 -0.81 table (3): packing height ver. evaporation loss and reduction for config. as1 shape of corrugated height(z),m evap. loss(kg/s) reduction% type1 1.1 43.3 57 type2 1.2 44.2 55 type3 1.3 44.8 53 type4 0.8 40 64 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 table(4):performance of cooling tower for different combinations arrangements performance of cooling tower( ) r=l/g ap1 ap2 as1 as2 1.51 0.59 0.68 1.24 0.61 1.625 0.58 0.64 1.15 0.60 1.628 0.55 0.61 1.09 0.51 2.14 0.53 0.59 0.99 0.44 2.24 0.50 0.57 0.95 0.43 2.63 0.48 0.53 0.89 0.39 table(5):evaporation loss at different combination(r=1.58) no. connection(combination) evaporation loss(kg/s) 1 ap1 66 2 ap2 69 3 as1 48 4 as2 70 table(6):performance of dry cooling section as1 outlet water temp.( o c) ntu area(m 2 ) δp (pressure drop) (torr) air flow(kg/s) ($/m 2 ) pp(pumping power) 30 4.1 2.3 1800 0.87 2502 3954320 30225 32 5.6 1.4 8800 0.91 1198 1754923 6923 34 6.9 1.2 3780 0.90 521 795434 1497 36 8.1 0.99 3800 0.85 79 204355 50.44 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 wet dry air air hot water cold water tlo-twi air air fig.(1.a):parallel combinations of wet-dry cooling tower (ap1). dry wet air air hot water cold water two-tli air air fig.(1.b):parallel combinations of dry-wet cooling tower (ap2). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 223 fig.(3):cooling tower heat and mass balance. fig.(3):cooling tower heat and mass balance. wet dry air hot water cold water tlo-twi air air fig.(2.a):series combinations of wet-dry cooling tower (as1). dry wet air hot water cold water two-tli air air fig.(2.b):series combinations of dry-wet cooling tower (as2). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 222 paper 4 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 1 effect of clay percentage in sandy clay soil on saturated hydraulic conductivity dr. khitam abdulhussein saeed iraq-baghdad al-mustansiriya university-college of engineering email: khitamhussein@yahoo.com received 28 june 2015 accepted 9 december 2015 abstract: hydraulic properties of sandy clay soil are very important for filtration, seepage and irrigation; so set of experiments were carried out for different samples of sandy clay in baghdad. measurements include bulk density, particle size distribution, clay percentage and hydraulic conductivity using constant head system. the aims of this study were to estimate equivalent saturated hydraulic conductivity (ks) for different clay percentages and predict porosity of sandy clay as function of clay percentage and porosity of sand and clay. nine samples of sandy clay soil have been tested in a hydraulic and soil laboratory (mustansiriya university). semi-empirical model was correlated to evaluate saturated hydraulic conductivity from clay percentage and results were compared with five empirical models selected from published literature were also used to predict ks. these empirical models were (puckett ,1985) , (ryjov and sudoplatov,1990), ( dane ,1992), (dheyaa ,2001)and (shevnin.et al, 2006). keywords: soil, sandy clay, hydraulic conductivity, porosity اثر نسبة الطين في الترب الرملية الطينية على التوصيل الهيدروليكي المشبع د. ختام عبد الحسين : الملخص ةيمول دورا لرترحودلجالار وا لالورل لوجلي ادر وع ةامااول ةوب التاووول ل موو الخواا اليدروللديدول لرتورل الرةردول الةد دولتعتبر .حوومرع الادوتوووك الي و وول ال,ولر وولجالتام الباموو لرببدبوكج وووبل الةوودب لالما ووردل ةخترفوول ةووب التوورل الرةردوول الةد دوول وو وورا ل المشبعل الميو ئل ل وب ةخترفل ةب . اا اليرف ةب الرواتل لا لتاددم الما ردل اليدروللديداليدروللديدل ةوتعمردب ,وم االوتفوع ال و ع توو موو ةوب توم بو كرالول ل ووبل الةودب لالموووةدل ليوا ةوب الةودب لالرةوا.الةدب لكجلي الت بو ولمووةدل لرترل الةد دول الرةردول حوب تار بو لتادودم أاتمر و ةعولاول ال تووئل اروو موا الترل الرةردل الةد دل ةختبرل الماائ لالتر ل الاوةعل الموت صور ل. ا الك تةبدادل ةختووة ةب ة شاواك تو ال الت ا ضو قدموع الما ردل اليدروللديدل المشبعل ةب وبل الةدب لتمع ةاوو ت ة خمس ة ةب الما ردل اليدروللديدل المشبعل للجه الما الك ليا (puckett, et al,1985: ryjov and sudoplatov,1990: dane,1992: dheyaa ,2001 : shevnin,2006) mailto:khitamhussein@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 2 1. introduction hydraulic conductivity (k) is the constant of proportionality in darcy’s law and as such is defined as defines the rate of movement of water through a porous medium such as a soil or aquifer or the flow volume per unit cross-sectional area of porous medium under the influence of a unit hydraulic gradient (m/d) commonly used units for hydraulic conductivity shown in (table 1) (puckett et al, 1985) and (nakhaei, 2005). soil water potential is the driving force behind water movement. the main advantage of the "potential" concept is that it provides a unified measure by which the water state can be evaluated at any time and everywhere within the soil-plant-atmosphere continuum (hillel, 1980). the forces subject soil water include gravity, hydraulic pressure, the attraction of the soil matrix for water, the presence of solutes, and the action of external gas pressure .at any point in the soil, total soil water potential is the sum of all of the contributing forces(hillel, 1980). measurement of hydraulic conductivity is problematic, considering the parameter can differ over several orders of magnitude across the spectrum of sediments and rock types, as indicated in (table 2). the parameter can also vary markedly in space, even with apparently minor changes in sediment characteristics. hydraulic conductivity is influenced by the properties of the fluid being transmitted (such as viscosity) as well as the porous medium (ranieri et al, 2012). hydraulic conductivity is also scale dependent, so that measurements taken at the core sample level may not be directly extrapolated to the aquifer scale. it is also direction dependent, so that hydraulic conductivity can be markedly different in the vertical from the horizontal. hydraulic conductivity cannot be directly measured but inferred from field, laboratory or modeled data. 2. theoretical approach in darcy’s law, saturated hydraulic conductivity is a constant (or proportionality constant) that defines the linear relationship between the two variables j and i (figure 1). it is the slope of the line (j/i) showing the relationship between flux and hydraulic gradient. solving darcy’s equation for k yields j/i (see equation 1). k = j/i (1) flux (j) is commonly expressed on a volume basis, and the units simplify to m/s. the hydraulic head difference (δh) is commonly expressed on a weight basis. it simplifies to centimeters of head, and the hydraulic gradient (i) becomes unit less (e.g., cm/cm) (ranieri et al, 2010). then, ks takes the same units as flux (m/s). flux represents the quantity of water moving in the direction of, and at a rate proportional to, the hydraulic gradient. if the same hydraulic gradient is applied to two soils, the soil from which the greater quantity of water is discharged (i.e., highest flux) is the more conductive (greatest flow rate). the sandy soil yields a higher flux (is more conductive) than the clayey soil at the same hydraulic gradient as shown in figure (1). the soil with the steeper slope (the sandy soil in figure 1) has the higher hydraulic conductivity. hydraulic conductivity (or slope "k") defines the proportional relationship between flux and hydraulic gradient, or in this case, of unidirectional flow in saturated soil. saturated hydraulic conductivity ("ks") is a quantitative expression of the soil’s ability to transmit water under a given hydraulic gradient (mason et al, 1957). http://soils.usda.gov/technical/technotes/note6.html#ref#ref http://soils.usda.gov/technical/technotes/note6.html#ref#ref http://www.connectedwater.gov.au/framework/hydrometric_k.php#table2 http://soils.usda.gov/technical/technotes/note6.html#eq5#eq5 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 3 the hydraulic conductivity for a given soil becomes lower when the fluid is more viscous than water. hydraulic conductivity (or ks) is expressed using various units. the units and dimensions depend on those that are used to measure the hydraulic gradient (mass, volume, or weight) and flux (mass or volume). to provide national consistency in defining permeability classes in soil surveys, uhland and o'neal (1951) evaluated percolation rates of about 900 soils. they defined "permeability" classes by distributing the percolation data equally among seven tentative classes (table 2). along with percolation data, they also studied 14 soil morphologic characteristics that affect water movement and that could be used to make predictions regarding permeability class. because of management effects on surface horizons, they confined their study to horizons below the surface layer. these classes were published in the 1951 soil survey manual (soil survey staff, 1951). mason et al. (1957) statistically analyzed uhland and o'neal's data. they concluded that it was overly optimistic that one could correctly place a given soil into one of seven permeability classes on the basis of percolation rates of five core samples taken at one site (the probability of being correct was 30%). a reasonable degree of reliability could be achieved if either more sites per soil were sampled or fewer classes were used. the study suggested that a 95% probability of making a correct placement could occur by using three to five permeability classes. in 1963, the ncss national soil moisture committee proposed a class/subclass "choice schema" with five to seven classes (table 2) (soil survey division, 1997). the proposal was provisionally accepted, pending the outcome of discussions comparing auger-hole percolation tests with the uhland core method and pending additional information on critical limits. when the soil survey division converted its previous database to the national soil information system (nasis) in 1994, saturated hydraulic conductivity replaced permeability. only the name was changed at this time. the values from the previous database were imported directly into nasis without modification. krumbein and monk (1943) proposed the equation: k=b(dm) 2 exp ( -σφ ) (2) where k is in darcies (1 darcy = 9.87e -09 cm 2 ), dm is the geometric mean grain-size diameter (mm), σφ is the geometric standard deviation (in φ units, where φ is –ln(d) and d is the grain-size diameter in mm), and a and b are empirical constants. this equation was based on experiments performed with sieved glacial outwash sands that were recombined to obtain various grain-size distributions. kozeny (1953) proposed an equation based on porosity and specific surface that may be written as (marshall 1958): k=n 3 /(s 2 p (3) where k is in cm 2 , s is the soil surface area of the medium per volume (cm 2 /cm 3 ), and p is an empirical constant. marshall (1958) went on to derive an equation for an isotropic material in which the mean radius of pores for each of ‘m’ equal fractions of the total pore space are represented by the corresponding mean radii (r1, r2, . . ., rm): http://soils.usda.gov/technical/technotes/note6.html#ref#ref http://soils.usda.gov/technical/technotes/note6.html#table2#table2 http://soils.usda.gov/technical/technotes/note6.html#ref#ref http://soils.usda.gov/technical/technotes/note6.html#ref#ref http://soils.usda.gov/technical/technotes/note6.html#table2#table2 http://soils.usda.gov/technical/technotes/note6.html#ref#ref http://soils.usda.gov/technical/technotes/note6.html#ref#ref al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 4 k=1/8{n 2 m -2 [r1 2 +3r2 2 +5r3 2 +……(2n-1)rn 2 ]} (4) where k is in cm 2 , ri (cm) is the mean radius of the ith fraction, and r decreases in size from r1 to rm. shepherd (1989) extended hazen’s work by performing power regression analysis on 19 sets of published data for unconsolidated sediments. ks=cd 2 10 (5) the data sets ranged in size from 8 to 66 data pairs. he found that the exponent in equation 8 varies from 1.11 to 2.05 with an average value of 1.72, and that the value of the constant c is most often between 0.05 and 1.18 but can reach a value of 9.85. values for both c and the exponent are typically higher for well-sorted samples with uniformly sized particles and highly spherical grains. 3. experimental work there are relatively simple and inexpensive laboratory tests that may be run to determine the hydraulic conductivity of a soil: constant-head method and falling-head method. the constant-head method is typically used on granular soil as shown in figure (2). this procedure allows water to move through the soil under a steady state head condition while the quantity (volume) of water flowing through the soil specimen is measured over a period of time. by knowing the quantity q of water measured, length l of specimen, cross-sectional area a of the specimen, time t required for the quantity of water q to be discharged, and head h, the hydraulic conductivity can be calculated: k=v l /[a t (h2-h1)] (6) the total head loss through the permeameter is indicated by the difference in elevation between the inflow and outflow water levels. 3.1 laboratory methods constant-head methods are primarily used in samples of soil materials with an estimated k above 1.0 × 10 2 m/yr, which corresponds to water filters medias. important considerations regarding the laboratory methods for measuring k are related to the soil sampling procedure and preparation of the test specimen and circulating liquid. the sampling process, if not properly conducted, usually disturbs the matrix structure of the soil and results in a misrepresentation of the actual field conditions. 3.2 materials and methods samples were classified according to particle size using a standard british soil classification system, detailed in bs 5930: site investigation. the samples were classified, diameters of soil particles at 10%, 20% and 50% cumulative weight determined, and the coefficients of uniformity, intercepts and porosity values were calculated. since the kinematic coefficient of viscosity is also necessary for the estimation of hydraulic conductivity, a value of 0.0874m 2 /day (0.897 *10 -6 m 2 /s) derived for a water temperature of (24-26 o c) is measured in the laboratory. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 5 4. results 4.1 prediction of porosity of sandy clay soil the total porosity nsc of the sandy clay soil is calculated from two empirical forms, the first is (ryjov and sudoplatov,1990) equation as following expressions: nsc= (ns c ) +nc.c, when c <ns (7) nsc= = c.nc, when c ≥ ns (8) where c is clay content, nc is clay porosity and ns is sand porosity. the second empirical equation is (dheyaa, 2001) model as following expression: nsc= ns (1c ) +nc.c (9) clay and sand porosities are considered as constant; therefore, soil porosity is a function of clay content. thus, porosity, grain size (or capillary radius) and tortuosity are not independent parameters. rather, they are interrelated in the sand-clay soil model. in this work clay content as the main factor was considered, as a function of other parameters such as soil porosity, tortuosity and formation factor. measurements for different porosities (0 to 1 ) were graphed and correlated as follow (r 2 =0.879 ): nsc= 0.244+0.036c (10) comparison between measured values of porosities and empirical equations of (ryjov and sudoplatov, 1990), (dheyaa, 2001) and (masch. et al, 1966) were shown in figure( 3). 4.2 effect of clay percentage on hydraulic conductivity of sandy clay soil filtration coefficient of soil depends on many factors, like clay content, grain size, type of clay, anisotropy of layered sediments, and two types of capillaries in clay. as a result, dependence of filtration coefficient from clay content is scattered. the scatter can be diminished with the help of calibration by using direct ks measurements. puckett et al. (1985) sampled six soils at seven different locations in the alabama lower coastal plain containing 34.6% to 88.5% sand-sized particles and 1.4% to 42.1% clay-sized particles, and used regression analysis to determine that percentage of clay sized particles was the best predictor of ks (r 2 = 0.77): ks=4.36*10 -3 exp (-0.1975 c) (11) where ks is expressed in cm/sec and c is the clay-sized particles (in percent) in the soil sample. bulk density and porosity, often used in other pedotransfer functions, were not highly correlated with ks for this data set of sandy soils. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 6 dane and puckett (1992) expanded the work of puckett et al. (1985) with two more data sets from the lower coastal plain of alabama. one set consisted of 577 ks and grain-size data pairs from 60 locations in a 0.5-ha agricultural field in south central alabama. nonlinear regression analysis yielded the equation (r 2 = 0.453): ks=8.44*10 -5 exp (-0.144 c) (12) the form of equation 6 that worked well for the previous data set yielded a significantly poorer fit for this data set. another set of data consisting of 130 pairs of ks and grain-size data from nine different soil series from the florida panhandle was also analyzed. nonlinear regression analysis resulted in the equation (r 2 = 0.443): ks=7.77*10 -5 exp (-0.116 c) (13) which also displayed a poorer fit than their previous study (puckett et al, 1985). comparison between measured values of hydraulic conductivity and empirical models of (puckett, 1985) and (dane and puckett 1992) for different clay percentages is shown in figure (4). 5. conclusions nine samples of sandy clay soil have been tested in a hydraulic and soil laboratory (mustansiriya university). the major conclusions can be drawn as follow: 1. filtration coefficient of sandy clay soil extremely depends on clay content, 2. measurements for different porosities (0 to 1) were correlated as (r 2 =0.879 ): nsc= 0.244+0.036c 3. empirical equation of hydraulic conductivity for different percentages of clay sized particles was correlated with the best predictor of ks (r 2 = 0.897) as: ks=0.019exp (-0.11 c) 6.references: [1] dheyaa, w. (2001)"hydrodynamic modeling of laminar flow in porous media".19 – 20 march, water resource, baghdad. [2] dane, j.h. and w.e. puckett. 1992. field soil hydraulic properties based on physical and mineralogical information. in proceedings of an international workshop: indirect methods for estimating the hydraulic properties of unsaturated soils. [3] hillel, d. 1980. fundamentals of soil physics. academic press. new york, ny. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 7 [4] krumbein, w. c. and g. d. monk. 1943. permeability as a function of the size parameters of unconsolidated sands. transaction of the american institute of mining, metallurgical and petroleum engineers, 151, 153-163. [5] kozeny, j. 1953. das wasser in boden, grundwasserbewegung. hydraulik, 280-445.( in german). [6] mason, d.d., j.f. lutz, and r.g. petersen. 1957. hydraulic conductivity as related to certain soil properties in a number of great soil groups—sampling errors involved. soil science society of america proceedings 21:554–561 marshall, t.j. 1958. a relation between permeability and size distribution of pores.journal of soil science 9, 1-8. [7] masch, f. d. and k. j. denny. 1966. grain-size distribution and its effect on the permeability of unconsolidated sands. water resources research 2, no. 4: 665–677. [8] marshall, j. j. (1958). a relation between permeability and size distribution of pores. journal of soil science ,9 :1-8. [9] nakheai, m. (2005). estimating the saturated hydraulic conducting of granular material using artificial neural network based on grain size distribution curve. journal of science, 16(1) :55-62. [10] puckett, w.e., j.h. dane, and b.f. hajek. 1985. physical and mineralogical data to determine soil hydraulic properties. soil science society of america journal 49, no. 4:831-836 [11] ryjov, a. a. and a. d. sudoplatov, 1990. the calculation of specific electrical conductivity for sandy clayed rocks and the usage of functional cross-plots for the decision of hydrogeological problems. in: scientific and technical achievements and advanced experience in the field of geology and mineral deposits research. moscow, pp. 27-41. [12] ranieri, v., antonacci, m. c., ying, g and sansalone, j. j. (2010). application of kozeny-kovacs model to predict the hydraulic conductivity of permeable pavement. transportation research record, 2195: 168-176. [13] ranieri, v., ying, g. and sansalone, j. (2012). drainage modeling of roadway systems with porous frication courses. journal of transportation engineering, 138(4) : 395-405. [14] shevnin, v., o. delgado-rodríguez, a. mousatov and a. ryjov, 2006. estimation of soil superficial conductivity in a zone of mature oil contamination using dc resistivity. sageep-2006, seattle. p.1514-1523. [15] shepherd r. g. (1989). correlation with permeability and grain size. ground water,27(5): 633638. [16] site investigation: a guide to bs 5930 : 1999 : code of practice for site investigations for higher education, 593. [17] united state department of agriculture, (1951). soil survey manual. u. s. dept. agr. hanb, 1 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 8 [18] uhland, r.e. and a.m. o'neal. 1951. soil permeability determination for use in soil and water conservation. scs–tp–101. united states department of agriculture, soil conservation service, washington, d.c. [19] uma, k.o., b.c.e. egboka, and k.m. onuoha. 1989. new statistical grain-size method for evaluating the hydraulic conductivity of sandy aquifers. journal of hydrology 108, 343-366. table (1): commonly used units for hydraulic conductivity (k)(hillel, 1980) description (m/d) (m/s) (mm/d) (mm/hr) extremely slow 0.000001 1.5741x10 -11 0.001 0.000041667 very slow 0.0001 1.5741x10 -9 0.1 0.0041667 slow 0.01 1.5741x10 -7 10 0.41667 moderate 1 1.5741x10 -5 1000 41.667 fast 10 1.5741x10 -4 10000 416.667 very fast 100 1.5741x10 -3 100000 4166.667 table (2): indicative hydraulic conductivities of some rock types (uhland and o'neal 1951) rock type grain size (mm) hydraulic conductivity k (m/d) clay 0.0005-0.002 10 -2 -10 -8 silt 0.002-0.06 10 -2 1 fine sand 0.06 -0.25 1-5 medium sand 0.25-0.50 5-20 coarse sand 0.50-2 20-100 gravel 2-64 100-1000 shale small 5x10 -6 5x10 -8 sandstone medium 10 -3 -1 limestone variable 10 -5 -1 basalt small 0.0003-3 granite large 0.0003-0.03 slate small 10 -5 -10 -8 schist medium 10 -4 -10 -7 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 9 figure (1): the relationship between flux and hydraulic gradient density. figure (2): constant head permeameter (after todd, 1959) plate 1: the constant head parameter test al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 10 template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 318 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. identifying factors affecting water resources of iraq by application of knowledge discovery in databases angham e. ali al-saffar university of baghdad, college of engineering, civil engineering department e mail: anghamalsaffar@yahoo.com ahmed zghair jaber al-joboury university of al-qadisiyah, college of engineering, civil engineering department e mail:ahmed.jaber@qu.edu.iq received on 26 october 2016 accepted on 9 august 2017 abstract: this study is concerning in recognizing and defining the factors affected on water resources in iraq, by application of knowledge discovery in database (kdd) techniques, kdd is a useful technique to discover the underlying concepts and unusual knowledge and that were not previously known from databases through a systematic process. there are lot software package usages with (kdd), while in this paper (microsoft excel) was used, since it is availableness and easygoingness. many factors are detected which have an impact on water resources in iraq. external factors have not controlled by iraq management such as water policies of riparian countries and climate factors (natural) while internal factors are under iraqi control such as irrigation methods and losses. some of these factors affected on quantity or quality or both. finally a successive management shall take care all these factors. keywords: kdd, water resources in iraq, climate factors, population growth rate, water losses, daily water consumption, population growth rate introduction this water plays important roles in the life of the community, as it needs to sustain life directly by using it for drinking and in making its own food, and indirectly, as in agriculture, industry, power generation, health and other services. investigation of various factors affecting water resources was the main task for researchers because shortage and the degradation of water quality at last 10 years ago. so many researchers were studied factors have an influence on water quality and quantity, where (jim 2002) demonstrated that freshwater resources will be subject to enormous pressures in the near future due to population growth. the most acute pressures will be in developing countries where water is scarce and population growth is high. (ilyas 2009) concludes that extremely difficult facing water supply for all sectors’ demands especially for dry years now and in the future because climate changes, high inconsistency of stream flows, continuing planning of development and land use. (mohammed 2011) studied verde river watershed in arizona, usa, through developing and applying a group of scenarios. in this exercise, three dimensions extremes were identified: climate change, demographics, and the economy. (dawadi 2013) mailto:anghamalsaffar@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 319 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. stated the climate variability and the rapid population growth were considered as major challenges of the water sustainability in the las vegas valley in southern nevada,usa. (al-washali 2011) found that volume of quantity of non-revenue water in sana'a water distribution system made up 38.75% of system input volume, while in iraq (al-ansari 2013) & (al-ansari et al.2015) have pointed out that the factors affecting water in iraq are divided into regional and local, regional including climate change and the cape project in turkey, while local factors include demand, distribution and drinking water systems. since, none of the previous researchers have discussed the factors affecting water resources in iraq in a comprehensive manner, so this study trying to do 1. knowledge discovery in databases (kdd) knowledge discovery in databases (kdd) means to discover the underlying concepts and unusual knowledge and that were not previously known from databases through a systematic process consisting of a number of stages(dunham 2003). kdd is not an easy process, which depends upon the data collection and management; figure (1). it also extends to the analysis, expectation, and prediction of what will happen in the future (fayyad et al. 1996). figure (1): the process of knowledge discovery in databases (fayyad et al., 1996) the (kdd) process includes many phases such as data discovery, data cleaning, data integration, data selection, data transformation, data mining, pattern evaluation, and knowledge presentation (ibrahim et al. 2013). while the final stage of knowledge discovery in databases is deems the beneficiary. this stage uses basic visual method to assist the beneficiary in understanding and interpreting the results of data mining (tsui et al. 2005). kdd is applied in many fields, especially in the field of management. it is applied in developing and the creating brief reports for a specific topic (fayyad et al.1997).the analysis of the general behaviour of the data (tuzhilin et al. 1996). to determine a particular characteristic this is similar in all data (ibrahim et al. 2013). finding a particular model for data analysis (klemettinen 1999). comparing strategies with each other to determine the most effective and influential relationship, finding aggregate relationships (ibrahim et al. 2013). in this study, the knowledge discovery technique is used to find and define the relationship between iraqi water resources and factors affecting these resources. data were collected for iraqi water resources from the following entities: the ministry of water resources(mowr). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 320 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the ministry of agriculture(moa). the ministry of environment(moe) the ministry of municipalities and public works(mompw). the ministry of planning / central statistical organization(mop/cso) the ministry of health(moh). the ministry of transportation(mot). the ministry of industry(moi). directorate of water resources of al-qadisiyah province. environment directorate of al-qadisiyah province. directorate of agriculture of al-qadisiyah province. directorate of water of al-qadisiyah province. directorate of sewage of al-qadisiyah province. 2. factors affecting water resources water resources are usually affected by many factors. some of these factors affect the quality and others affect the quantity while some have effects on both quality and quantity. 2.1. water policies of riparian countries most iraqi surface water sources are running from neighboring countries such as turkey and iran, or pass through, such as syria. figure (2) shows the participation rates of these countries of water incoming to iraq and the distance traveled by the water river through those countries. thus, effects of water policies and projects implemented by those countries on the water supply to iraq are shown in figures (3) and (4) which illustrate the decrease in the rate of supply of the euphrates and tigris rivers, respectively. these projects have had the effects of decreasing water supplies entering iraq. as obvious, the shortfall in supply of the tigris river is small compared to the supply shortage of the euphrates river. this is caused by the large number of dams built on the euphrates river basins compared to the tigris river as shown in figures (5) and (6) which show storage capacity and location of those projects. 0% 20% 40% 60% 80% 100% distance discharge distance discharge euphrates tigris percentage of contribution turkey syria iraq iran figure (2): percentages of riparian states contribution in distance and waters of tigris and euphrates rivers. ((mowr, 2015) data/researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 321 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3): decrease in the overall rate of euphrates river supply ((mowr, 2015) data/researcher) figure (4): decrease in the overall rate for the supply of the tigris river ((mowr, 2015) data/researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 322 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 0 5 10 15 20 25 30 35 40 45 tigris euphrates storage capacity (km3) turkey syria figure (5): storage capacity of the storage projects built on the tigris and euphrates rivers in riparian states. ((mowr, 1025)data/researcher) figure (6): map of locations of dams and control projects on the tigris and euphrates basins in the riparian countries (mowr, 2013) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 323 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. in addition, the riparian countries at the top of the river basin (as mentioned previously) have effects on water quality as a resultant of establishment of dam projects, and agricultural projects. these projects lead to high concentrations of dissolved salts (tds) in the water. on the other hand, those projects cause a major reduction in iraqi water share and that leads to high concentrations of dissolved salts in the water. table (1) shows concentrations of total dissolved salts in the water of the euphrates river during the period (1925-1973) compared to the period (1975-1998)(al-hadithi 1978), (parton 2001), a period that followed the establishment of keban and the al-tabaqa dams in the upper river basin. table (1): mean annual tds within euphrates river in iraqi border before and after the construction of keban and the al-tabaqa dams (al-hadithi 1978; parton 2001) station tds (ppm) period (1975-1998) period(1924-1973) al qaim 1000 467 2.2. climate factors (natural) many changes happen in the climate and atmosphere of the earth and these changes are due to high concentrations of carbon dioxide and other greenhouse gases. the temperature of land and oceans has raised by (0.5) degrees celsius in the last fifty years (fao 2013), while the temperature in iraq has raised by average 1.5 ° c as shown in figure (7). temp. rise above overall average 0 5 10 15 20 25 30 35 40 1 2 3 4 5 6 7 8 9 10 11 12 month degree average 2008-2012 average for 40 year figure (7): temperature rise over iraq above overall average ((mot, 2013) data/ researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 324 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. among the most prominent repercussions of global warming is the high annual rate of evaporation (due to high temperatures and low relative humidity). these are observed especially in arid, semi-arid, and sub-humid areas, including iraq and the headwaters of euphrates and tigris rivers. figure (8) shows lower rates of relative humidity in iraq. it also results in a significant decrease for rainfall as shown in figure (9). the lack of rates of falling rain compared to rates of evaporation from reservoirs and waterways, as shown in figure (10), regarding the main reason for the decrease of water resources in iraq. in addition, there are an impact of weather conditions and climate on water quality through high temperatures and low relative humidity and rain, which cause high rates of evaporation, which leads to high concentrations of salts particularly in water reservoirs 2.3. factors affecting the municipal demand they represent the factors that cause the increase in demand for water used by the population for domestic use such as preparing food, drinking, bathing, and others. the amounts of water necessary for these activities are usually different from state to state. in iraq, these amounts are determined for the purposes of the designs and calculations by the directorate general of water / ministry of municipalities and public works up to 300 liters per person per day. (cso 2013) therefore, the affecting factors on demand for municipal are: relative humidity 20 30 40 50 60 70 80 1 2 3 4 5 6 7 8 9 10 11 12 month % average for 40 year average(2008-2012) figure (8): decrease relative humidity below overall average over iraq ((mot, 2013) data/ researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 325 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 0 20 40 60 80 100 120 140 1 2 3 4 5 6 7 8 9 10 11 12 month mm overall(1938-2012) average(2008-2012) figure (9): decrease precipitation below overall average over iraq ((mot, 2013) data/ researcher) figure (10): losses in volume due to evaporation in iraqi dames ((mowr, 2015) data/ researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 326 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.3.1. population growth rate. the control of growth rate is directly reflected on quota per capita of water share. the international organizations assume (1000 m3 per person per year) (fao 2013) for water scarcity, where water scarcity represent the lowest amount of quota per capita of annual revenue of water for drinking, hygiene, agriculture, industry and municipal services and meet all their needs. figure (11) shows the decreasing quota per capita of these supplies. figure (11): decreasingly of ration per capita of water revenue the population growth directly rate affects the increase in municipal water demand with time. figure (12) illustrates the increasing demand from (3.7 billion cubic meters) in (2012) to (7.7 billion cubic meters) in (2060) for growth rate (1.5%), while, increase demand to (12.9 billion cubic meters) in (2060) for growth rate (3%), so the sensitivity coefficient of municipal water demand to growth rate of the population was (68.2%) (al-joboury 2014).the increase of population is a major reason to increase agricultural water demand, because it was increasing demand for food and agro-industrial products. pollution of municipal activity highlights the most considerable impact of contaminants such as untreated sewage, water-borne tanks, and tanker trucks, table (2) describe it. the following can be observed: the percentage of sewage networks does not exceed (33%) of the total area of urban cities therefore, a large proportion of untreated water is thrown into rivers and streams. most of the sewage treatment plants operate at higher capacity than their design capacities resulting in low efficiency of the treatment, which lead to water contamination. there are activities and pollutants sources behind municipal activities, which disposal to treatment units and rivers. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 327 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (2): the number of activities that the disposal of contaminated water into sewer systems (wastewater, rain, common) in iraq (mompw, 2013) slaughter houses other total treated activities total activities untreated no. of treated activities no. of untreated activities no. of treated activities no. of untreated activities 0 6 34 197 43 104 2.3.2. daily water consumption the amount of daily consumption of water by a single person has a direct impact on municipal water demand. figure (12) illustrates the changing water demand when the amount of municipal water consumption per person per day was changed. demand was increased from (2.5 billion cubic meters) in (2012) to (8.6 billion cubic meters) in (2060) when the rate of consumption (200 liters per day), while increasing the demand from (3.7 billion cubic meters) in (2012) to (12.9 billion cubic meters) in (2060) when the rate of consumption (300 liters per day). therefore, the sensitivity coefficient of municipal water demand to daily consumption amount was (100%)(al-joboury 2014). domestic demand 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 2000 2010 2020 2030 2040 2050 2060 2070 year km3/year groth 1.5%&200 liter groth 1.5% & 300 liter groth 3%& 200liter groth 3% & 300 liter figure (12): influence of population growth rate and daily consumption on water demand. ((cso, 2015) data/researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 328 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.3.3. water losses loss of water within the network of rivers and canals, streams and irrigation network figure (13) shows types of irrigation’s channels, lengths, and lining material for these canals )mowr, 2013(. this figure illustrates that the proportion of erodible canals length to the total length of canals was approximately (90%))mowr, 2013). this indicates large losses in water supplies, which may be up to 30% of the revenues of water (al-joboury 2014). these losses are caused by leakage from the walls and seepage from canals bed. another source of losses in water quantities is losses in water supply networks (water distribution systems). loss of water in supply networks is a worldwide problem, particularly developing countries in arid and semi-arid regions. in iraq, there are no water meters to measure water consumptions in most iraqi cities, therefore, no accurate statistics for losses, so methods of measuring losses are absent. hence, daily treated water represents daily water consumption with zero losses. 0 20 40 60 80 100 120 140 160 180 suspended unerodible erodible pipelines material lining length (1000 km) water coarse distributed canal lateral canal main canal figure (13): lengths of ducts for water depending on the material lining for the canals ((mowr, 2013) data/researcher) 2.3.4. urbanization urbanization that means transformation of undeveloped land into developed land. that leads to an increasing in demand of water supply (municipal and industrial) in addition to increasing in sewage productions. 2.4. factors affecting the agricultural demand agricultural water demands in iraq represent one of the highest demands. the proportion of consumption in this sector was (86%) of the total water consumption (mowr, 2013). figure (14) shows the proportions of water consumption for the various sectors in iraq. therefore, the factors affecting water al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 329 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. consumption in the agricultural sector have a significant impact on the water demand. this factor represented by irrigation methods. irrigation methods are one of the main reasons for high agricultural water demand, because its impact on the losses of water in addition to their direct impact on productivity. each methods of irrigation have efficiency of transfer, efficiency of application, and efficiency of production. therefore, the selection of appropriate irrigation method has higher efficient means, higher productivity, and consequently less areas of land and less agricultural water demand. table (3) shows the efficiency of conveyance and application of various methods of irrigation. agriculture is one of the most commonly used water sectors in iraq. large proportion of this water was back return directly to the waterways by drainers’ networks or indirectly through natural drainage by groundwater. so agricultural drainage is one of the largest contaminants because, its flow size and soluble salts compared to the rest of other pollutants. figure (15) shows drainers which drained into the euphrates river. in the other hand, agricultural sector has wastes of chemical fertilizers, pesticides, and toxins, which are used neither control nor technical guidance by specialized institutions. percentage of water usages 86% 3% 5% 6% agricultural demand municipal demand industrial demand ecological demand figure (14): ratios of water demand by various sectors ((mowr, 2013) data/researcher) table(3): efficiency of conveyance and application according to irrigation method ((fao 2013) data/ researcher) efficiency of irrigation method application conveyance 0.60 0.9 surface 0.80 0.95 sprinkler 0.90 0.99 trickle al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 330 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (15): drainers that drained into the euphrates river. (moe, 2006) 2.5. factors affecting industrial demand the most important factors affecting the industrial demand are the potential growth of this sector, where this sector was suffering from stagnation and backwardness for long periods. the potential growth is concluded in figure (16). this figure shows the number of projects and industrial plants, which began in (5 years). industrial sector had a rate of (100) plant for each period within interval (1970-2000), but increased within interval (2006-2012) to reach (493) projects (cso 2013). in quality scope, there are hundreds of food industries, chemical, construction and petrochemical ... etc., which contributes effectively to the pollution of fresh water. industrial sectors have necessarily needs of water as a raw material in industry or as a means to cool the engines and equipment used by these industries. so, most of these factories are located nearby rivers. perhaps the most polluting industries for water are the chemical and petrochemical industries such as the pharmaceutical industry, pesticides and toxins, detergents, food industry. these chemicals and organic materials lade by huge amounts of contaminated water. figures (17) and (18) show quantities of industrial pollutants discharged into rivers. in addition, the drainers to the sewer system and to ditches will return to the rivers because they relate to rivers at the end of the session. the impact of pollutants resulting from the municipal activities, agricultural, and industrial can be observed by increasing the concentration of contaminated items such as (tds, so4, th, cl) inside iraqi territory as shown in the figures (19), (20), and (21). these figures were painted based on data collected from monitoring stations, there location shown in figure (22). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 331 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 0 100 200 300 400 500 600 700 800 900 -1970 19711975 19751980 19811985 19861990 19911995 19962000 20012005 20062011 period seemed to run projects(year) no. of industrial projects(unit) figure (16): number of projects and industrial plants depending on the history of engaging ((osc. 2013) data/researcher) 8.41 3.60 21.6 5.9 27.4 9906.4 9918.4 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 sewage industrial mixed total million m3/year non-hazardous hazardous figure (17):the amount and type of water discharged from industrial facilities ((osc. 2013) data/researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 332 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 0 10 20 30 40 50 60 70 80 90 100 hazardous non-hazardous % other tigris sewage network euphrates drainer figure (18) : destination of discharge and ratio of hazardous and non-hazardous waste ((osc. 2013) data/researcher) dyala river2012 di5bdi5di4di3di2 di6 di7 0 500 1000 1500 2000 2500 0 1 2 3 4 5 6 7 8 stations ppm cl t.h. so4 t.d.s figure (19): changing concentration of pollutants in diyala river with respect to distance ((moe, 2013) data/researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 333 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. tigrise river in 2012 t34t33t31t28t24t17t10t1 0 200 400 600 800 1000 1200 1400 0 1 2 3 4 5 6 7 8 9 stations ppm cl t.h. so4 t.d.s. figure (20): changing concentration of pollutants in tigris river with respect to distance ((moe, 2013) data/researcher) eughrates in 2012 e16 e19e14e10e1 0 500 1000 1500 2000 2500 3000 0 1 2 3 4 5 6 stations ppm cl t.h. so4 tds figure (21): changing concentration of pollutants in euphrates river with respect to distance ((moe, 2013) data/researcher) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 334 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (22): locations of monitoring stations (moe, 2013) conclusions according to previous charts and tables can be concluded: annually ration per capita was continuously decreasing and reached about level of crisis, these was due to water policies of riparian countries and global warming. annual losses due to evaporation of water bodies in reservoirs is very large, equivalent to 1% of iraq's annual water revenues, (i.e. satisfied 30% of municipal demand). in the other hand lost quantities were cause increasing in concentration of pollution such as tds, th, so4, and cl agricultural sector has a large ration of consumed water, therefore has a large ration of losses. main losses in agricultural were due to using an ancient irrigation ways and erodible canals. these losses were about to be (31.6%) of agricultural demand, or equal (11.556 mcm/year), (i.e. 31% from iraqi water revenue in 2014). industrial sector consumed for industrial proses approximately (50%) from total industrial demand, these water can be recycled by using closed production cycle, (i.e. satisfied 80% of municipal demand) however, municipal sector has a smallest demand among other sectors, but can be saving about (30%) of municipal demand by reducing daily water consumption per capita. these processes can be done by arising efficiency of water usages and reducing water losses in network al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 335 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the main reasons to degradation in water quality are discharge agricultural drain, municipal sewages and arising level of ground water (obviously in station (e10) on euphrates, in station(t17) on tigris an station(di4) on dyala) so, water resources are affected by many factors, those factors classify in to factors have influences on quality of water and the other have influences on quantity of water. water resources management when have an ability to control those factors, so it is regarded as an internal factors. while when water management do not have to do anything to prevent those factors, so called external factors. some of those factors affect water demand and others affect water supply. then the main factors affecting water resources in iraq can be summarized in figure (23). in the other side, factors affecting water resources of iraq don’t have the same impact on water resources. therefore, a successful water management must consider all these external and internal factors in their policies and plans. figure (23): factor affecting water resources al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 336 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. references 1. al-ansari, n. a., management of water resources in iraq: perspectives and prognoses, scientific research, engineering, 5, 2013,pg 667-684. 2. al-ansari, nadhir, ammar a. ali, sven knutsson, iraq water resources planning: perspectives and prognoses, jeddah saudi arabia jan 26-27, 2015, 13 (01) part xiii, 2015. 3. al-washali, t. m., non-revenue water management in sana'a water distribution system, faculty of graduate studies, the university of jordan, institute for technology and resources management in the tropics and subtropics (itt) university of cologne for applied sciences, master of science in iwrm, 2011. 4. al-hadithi, a. h., optimal utilization of the water resources of the euphrates river in iraq, arizona, university of arizona. ph.d. thesis,1978. 5. al-joboury, ahmed zghair jaber, integrated management system for sustainability of water resources in iraq, baghdad, university of baghdad, college of engineering, ph.d. thesis,2014 6. cso., ecological surveying on iraq for industrial sector in year 2012/ second report, baghdad, iraq,2013 7. cso., ecological statistics on iraq in year 2014, baghdad, iraq.2015 8. dawadi, s., and sajjad ahmad, evaluating the impact of demand-side management on water resources under changing climatic conditions and increasing population, journal of environmental management 114, 2013, pg 261-275. 9. dunham, m. h., data mining: introductory and advanced topics, prentice hall, 2003. 10. fao, fao statistical yearbook 2013,world food and agriculture, rome, fao, 2013. 11. fayyad, u., piatetsky, g., and shapiro, p. s., from data mining to knowledge discovery: an overview, aaai press / the mit press, menlo park, ca. 1997, 1-34. 12. fayyad, u., piatetsky, g., ashapiro, p. s., and uthurusamy, r., advance in knowledge discovery & data mining, cambridge, ma, the aaai press/the mit press, 1996. 13. ibrahim, l. m., dujant, basheer, and mahmod, mahmod s., a comparison study for intrusion database (kdd99, nsl-kdd) based on self organization map (som) artificial neural network, journal of engineering science and technology 8(1), 2013,pg 107 – 119 14. ilyas, m., mobin-ud-din ahmad, stefan uhlenbrook, hugh turral and poolad karimi, analysing stream flow variability and water allocation for sustainable management of water resources in the semi-arid karkheh river basin, iran, physics and chemistry of the earth (34), 2009, pg 329-340. 15. jim, s. w., and peter, j. gregory, water resources and their use in food production systems, aquat. sci. (64), 2002,pg 363-375. 16. klemettinen, m., a knowledge discovery methodology for telecommunication network alarm databases, ph.d. thesis report a-1999-1, university of helsinki, 1999. 17. moe, state of the environment in iraqi company report 2006, baghdad, iraq, the directorate of maritime inspection, 2006. 18. moe, unpublished data, baghdad, iraq, 2013. 19. mohammed, i. m., hoshin v. gupta, seshadri rajagopal, scenario development for water resources planning and watershed management: methodology and semi-arid region case study, environmental modeling & software (26), 2011,pg 873-885. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 337 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 20. mompw, unpublished data, baghdad, iraq, 2013. 21. mot, unpublished data, baghdad, iraq, 2013. 22. mowr, unpublished data, baghdad, iraq, 2013. 23. mowr, unpublished data, baghdad, iraq, 2015 24. parton, h., the mesopotamian marshlands: demise of an ecosystem early warning and assessment, technical report, rome, unep/dew a/tr.01-3 rev. 1 division of early warning and assessment, 2001. 25. tsui, kwok-leung, jiang, w., alp aslandogan, y., data mining: methods and applications, school of industrial and systems engineering, university of texas, 2005. 26. tuzhilin, a. and silberschatz, a., what makes patterns interesting in knowledge discovery systems, ieee trans. on knowledge and data engineering 8, 1996, pg 970-974. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 287 utilization of shredded tetra-pak in hot mix asphalt asst. lecturer harith k. k. ajam, civil engineering department, college of engineering, university of babylon email: harithajam@yahoo.com abstract the growth in various types of industries together with population growth has resulted in enormous increase in production of various types of waste materials, world over. the creation and disposal of non-decaying waste materials have been posing difficult problems in developed as well as in developing countries. the efforts to find useful applications of some of the waste products in highway construction have given encouraging results. the use of tetra-pak (tpa) containers to pack food of various kinds including milk, juice, meat, etc. has become a common practice. to produce packaging materials, tpa uses paperboard (73%), plastic (22%) and -for aseptic packagesaluminum foil (5%). however the disposal of the tetra-pak in large quantities has been a problem and is of great concern, particularly in big cities. in case it is possible to find useful application for the waste tpa, there will be substantial scrap value for this waste product and therefore they will be collected and sold by interested persons, instead of being littered or thrown out in the dust bins or into the road side drains. the present study investigates the benefits of using shredded tetra-pak in binder layer flexible pavement mix. a (1-6)mm in particle pieces of tpa had been added. the mix had been tested by marshall testing method. mix volume relationships, marshall stability and flow with the different percent of shredded tpa were recorded. a control binder mix is used with (5)% asphalt content for comparison and the same asphalt content used for all specimens. the research concluded that using tpa in the range of (1-1.5)% in hma increase the marshall stability, flow and air voids and decrease in voids filled with asphalt. for (2)% there was decrease in stability, air voids and voids filled with asphalt (vfb) and increase in flow. in (3-above)% the mix start scattered in the test. ( المقطعة في الخلطات االسفلتية الساخنةtetra-pakعلب )استخدام مدرس مساعد حارث خليل كاظم عجام جامعة بابل، كلية الهندسة قسم الهندسة المدنية البحث ملخص لمختلف الصناعات إضافة للنمو السكاني عالمياً سبب زيادة في كثير من أنواع المخلفات. االنتاج النمو المضطرد ايجاد طريقة ووالتخلص من هذه المخلفات وخاصة غير القابلة للتحلل يعتبر مشكلة في كثير من الدول وخاصة النامية منها. ائج مشجعة.الستخدام جزء من هذه المخلفات في مجال هندسة الطرق اعطى نت اصبح منتشراً وشائعاً. تنتج ( لحفظ مختلف االطعمة مثل الحليب والعصائر واللحوم وغيرهاtetra-pakاستخدام علب ) %( من البالستك، وللمنتجات التي تحتاج الى تغليف معقم 22%( من الورق المقوى، )37هذه العلب من طبقات من المواد االتية ) %(. وأصبح التخلص من الكميات الكبيرة من مخلفات هذه العلب مشكلة كبيرة وخاصة في 5وم )تضاف طبقة رقيقة من االلمني mailto:harithajam@yahoo.com al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 288 المدن الكبيرة والنامية. إيجاد طريقة لالستفادة من مخلفات هذه العلب سيرفع من قيمتها كمخلفات وسيوجد فرص عمل لجمعها نب الطرق وفتحات التصريف.، بدل ان تكون مبعثرة أو مرمية في سلة المهمالت أو على جواوبيعها في هذا البحث اضيفت هذه العلب بعد تقطيعها في الخلطة االسفلتية ومحاولة معرفة تأثيرها على خواص الخلطة. قطعت وحساب وتم تسجيل قيم الثبات والمرونة ،مم( واضيفت لخلطة طبقة رابطة وتم فحص النماذج بطريقة مارشال6-1العلب بأبعاد ) ية للمختف نب إضافة قطع العلب.العالقات الحجم %( للمقارنة واستخدمت تثبيت هذه النسبة لبقية العينات. 5تم االعتماد على خلطة طبقة رابطة قياسية بنسبة اسفلت ) (% سيزيد من ثبات مارشال، كما يسبب 1.5-1استنتج البحث ان استخدام نسبة من العلب المقطعة في الخلطة االسفلتية بحدود ) (% هناك نقصان في ثبات مارشال، 2ونسبة الفجوات الهوائية، ويقلل نسبة الفجوات المملوءة باالسفلت. نسبة )مرونة زيادة ال (% فالعينة تتفتت وتفشل 7ونقصان في الفجوات الهوائية والفجوات المملوءة باالسفلت، وزيادة في المرونة. أما لنسبة أكبر من ) تحت ضغط جهاز مارشال. keywords: asphalt pavement, recycling materials, tetra-pak, hma, highway pavement introduction: recycling waste materials is a valuable solution to the expensive and environmentally unacceptable disposal problem for these products. numerous waste materials result from manufacturing operations, service industries, sewage treatment plants, households and mining. the hma industry has been pressured in recent years to incorporate a wide variety of waste materials into hma pavements. this has raised the following legitimate concerns: (a) engineering concerns such as effect on the engineering properties (for example, strength and durability), impact on production, and future recyclability; (b) environmental concerns such as emissions, fumes, odor, leaching, and handling and processing procedures; and (c) economic concerns such as life cycle costs, salvage value, and lack of monetary incentives. the waste materials can broadly be categorized as follows: (a) industrial wastes such as cellulose wastes, wood lignin, bottom ash and fly ash; (b) municipal/domestic wastes such as incinerator residue, scrap rubber, waste glass and roofing shingles; and (c) mining wastes such as coal mine refuse [kandhal-1992]. shingles is one of the types of waste fibers used in hma. there are two types: organic (paper) and fiberglass. the use of recycled asphalt shingles (ras) in hma can provide several advantages, including conservation of landfill space, lower hma material costs, and improved mix properties [bartlett-2007]. a study evaluated the properties of stone mastic asphalt mixtures made with paper mill sludge, as well as wastepaper, as fiber additive. asphalt contents between 5 and 6 percent and sludge or fiber contents between 0.3 and 0.5% resulted in marshall specimens with properties generally passing the department of public works and highways specifications for both medium and heavy traffic road pavement [mari-2009]. low density polyethylene is major part of the waste plastic stream. its use as a recycled additive is hma concrete pavement extends back to the mid-1970’s. the resistance to deformation of hma concrete modified with approximately (5%) low density polyethylene is significantly better than that of the unmodified mix [little-1993, bindu-2010, justo-2004]. the utilization of fibers in asphalt mixtures is not a new concept; in fact, it has been in use since the early 1900s. the purpose of the fibers was to essentially stabilize the mixture and prevent bleeding of asphalt during hot weather service. use of fibers in hma did not come until the late 1950s when the us army corps of engineers, the asphalt institute, and the johns-manville co., an asbestos fiber manufacturer, initiated the first evaluation of asbestos fibers in hma. results indicated that mixtures containing fibers showed an increase in tensile strength, compressive strength, stability, ability to sustain load after reaching maximum stability, and resistance to weathering [putman-2011, forta-fi-2009, yoo-2009]. using shredded tetra-pak (tpa) may be desirable for the production of hot mix asphalt (hma) pavements. it can reduce the waste materials in beneficial way by eliminating the al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 289 environmental impact of these materials and decrease the disposal budgets required. the properties of the hma mixture with tpa were evaluated and compared with conventional hma mixture. raw materials: to produce packaging materials, tpa uses paperboard (73%), plastic (22%) and -for aseptic packagesaluminum foil (5%). raw materials production has the greatest environmental impact of all stages within the package life cycle. the plastic (polyethylene) is used in layers on both sides of the paper structure to protect the package from inside and outside moisture. cartons designed for long life or high acidity content contain aluminum foil, which is about 6-micrometer (0.00024 in) thin. this layer provides additional protection for the content against oxygen, bacteria, undesired flavors and light; fig. (1) shows tpa packaging components [abreu-2011, wikipedia-2012]. tpa introduces a composite of three recycled materials paper (shingle), polyethylene (plastic), and fibers (aluminum foil). this study tried to investigate the change of hma properties using shredded tpa. the tpa has been cleaned with water from any substance and dried in oven (60 o c) then hand shredded to (1-6mm) particle size. the shredded tpa used in the mix. test results and discussion: a binder layer hma had been used as control mix with (5%) asphalt cement grade (40-50). five specimens for each of control and shredded tpa with (0.5, 1, 1.5, 2, and 3)% -30specemens in totalprepared and tested with marshall test method with the same asphalt content. table (1) shows a summary (average) of the test results with the binder layer specifications according to general specifications for roads and bridges, iraq, (r9-2007). figures (2, 3, 4, 5, and 6) show the relationship between the tpa content and the marshall stability, flow, density, air voids, and voids filled with asphalt (vfb). the test results show improvement in marshall stability within (0.5-1.5)% tpa. this may be introduced from the binding effect of plastic and reinforcement effect of fibers which increase the stiffness of the mix. in another hand, marshall flow increases due to the sliding effect and lack of interlock of the tpa particles (have smooth faces). for (2%) tpa content the stability start to decrease due to the increase of lack on particle interlock and reach the failure with (3%) tpa content. density is decreasing with (0.5-1.5)% tpa content and decreases with (2%). vfb show a decreasing trend. the air voids increased for (0.5-1.5)% tpa content and increases for (2)%. the decrease in density within (0.5-1.5)% range of tpa content may be produces because the orientation of the tpa particles which produce more air voids, in other hand the increase in density with (2%) may be effected by the rearrangement of tpa particles and produce denser mix. conclusions and recommendations: based on this study of the utilization of shredded tpa in hma mixtures, the following findings were made:  the marshall stability value of improved within (0.5-1.5)% tpa content, which is higher than the prescribed value of 7 kn for conventional binder layer mix.  the flow value of mix with (0.5-1.5)% tpa was found to be larger than the range of the prescribed value (2 4mm) and increases in trend with tpa content increase.  mix density and vfb decreases with the increase of tpa content and air voids increases. as a conclusion, the mix with tpa may not be used as binder layer according to the procedure taken in this research. on other hand, using tpa within (0.5-1.5)% increase stability which improve the deformation resistance. while increasing in flow and air voids values cause an adverse effect on other properties. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 290 some recommendations may be taken for future researches including: using controlled shape and finer tpa shredded particles, different mixing techniques and mixing temperatures, experiment with different layer types and different test devices for evaluation other properties. references: abreu, mario, “recycling of tetra pak aseptic cartons”, tetra pak canada inc. markham, canada, 2011. bartlett, nathan, and et.al., “recycling shingles into asphalt pavements”, pavement design, construction, materials enterprise, 109 dillman hall, michigan technological university, dec.-2007. bindu c.s 1 & dr. k. s. beena 2 , “waste plastic as a stabilizing additive in stone mastic asphalt”, reader 1 , professor 2 , division of civil engineering, school of engineering, cochin university of science and technology, cusat, cochin 682022, kerala, india, 2010. forta-fi, “guide specification for fiber-reinforced asphalt cement concrete”, forta corporation, 100 forta drive, grove city, pa 16127, www.fortacorp.com, 2009. “general specifications for roads and bridges (r9)”, state organization of roads &bridges, ministry of housing & construction, republic of iraq, 2007. justo, c.e.g., and et.al, “utilization of waste plastic bags in bituminous mix for improved performance of roads”, prof., centre for transportation engineering, bangalore university, bangalore, 2004. kandhal, prithvi s., “waste materials in hot mix asphalt-an overview”, assistant director, national center for asphalt technology, ncat report no. 92-6, dec-1992. little, d.n., “enhancement of asphalt concrete mixtures to meet structural requirements through the addition of recycled polyethylene”, use of waste materials in hma, astm stp 1193, h. fred waller, ed., american society for testing and materials, philadelphia, 1993. mari, erlinda l., and et.al., “paper mill sludge as fiber additive for asphalt road pavement”, forest products research and development institute, department of science and technology, college laguna, jun-2009. putman, bradley j., “effects of fiber finish on the performance of asphalt binders and mastics”, glenn department of civil engineering, clemson university, 109 lowry hall, clemson, sc 29634, usa, sep-2011. wikipedia, “tetra-pak”, wikipedia, the free encyclopedia, www.wikipedia.org, jun-2012. http://www.fortacorp.com/ http://www.wikipedia.org/ al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 291 yoo, pyeong jun, and et.al., “characteristics of mono-strand fiber-reinforced hot-mix asphalt mixtures”, highway research division, korea institute of construction technology, goyang, gyeongi, rep. of korea, 2009. table 1. marshall test results tpa flow density stability air voids voids filled with asphalt (vfb) % mm gm/cm 3 kn % % specifications 2 4 -7 3 5 70 85 0 control 2.53 2.522 7.25 3.14 82.30 0.5 4.65 2.484 7.32 4.16 80.20 1.0 6.67 2.460 7.47 5.64 78.10 1.5 12.58 2.270 7.70 13.25 72.60 2.0 18.96 2.351 6.39 12.02 67.50 fig. 1 tetra-pak (tba) packaging components with microscopic image al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 292 fig. 2 shows the relation between %tpa and marshall stability fig. 3 shows the relation between %tpa and marshall flow fig. 4 shows the relation between %tpa and density al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 293 fig. 5 shows the relation between %tpa and % of air voids fig. 2 shows the relation between %tpa and % voids filled with asphalt (vfb) al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 74 effect of rc and sbr as coating curing materials on properties of highway rigid concrete pavement dr. shakir al-busaltan 1 , ma'aly al-ani 2 , ola al-jawad 3 1 lecturer, department of civil engineering, university of kerbala, karbala, iraq shakerfa2003@yahoo.com 2 asst. lecturer, department of civil engineering, university of kerbala, karbala, iraq masaasta@yahoo.com 3 researcher, department of civil engineering, university of kerbala, karbala, iraq aljawadola@yahoo.com received 21 september 2015 accepted 9 december 2015 abstract the surface to volume ratio of concrete pavement is large, also, due to hot climate of iraq, coating concrete pavement after casting is essential to ensure vital curing, consequently to obtain significant engineering properties. this research work reports the results of a study performed to evaluate the engineering properties of concrete coated with concrete surface coatings solutions; two types of coating were used representing co-polymer (styrene-butadiene rubber, sbr) and byproduct material (residue crude, rc). different coating solutions were prepared from these solutions, individually and collectively; i.e. 100% sbr, 75% sbr+25% rc, 50% sbr+50% rc, 25%sbr+ 75%rc, and 100%rc. the engineering properties of the uncoated and coated concrete samples were evaluated by assessing compressive strength, flexure strength and hardness for concrete convenience for highway rigid pavement. the compressive strength was evaluated for the specimens at 7, 14, 28 and 90 days, where flexure and hardness were evaluated at 28days. the results showed that the coated samples with both sbr and rc performed noticeably better in contrast with uncoated samples under air-dry conditions. additionally, obvious differences in the performance of the collective solutions were recognized. from the results, however, local byproduct materials have been proven as a significant coating materials suitable to enhance the concrete used for pavement purposes. keywords: compressive strength, concrete pavement, flexural strength, rc, sbr. الجاسئة طية انضاج على خواص خرسانة بلطات الطرقغكمواد ت sbrو rcتاثير مهندسة عال الجواد م.م. معالي العاني شاكر البو سلطانم.د. قسم الهندسة المدنية / كلية الهندسة قسم هندسة النفط و البتروكمياويات/ كلية الهندسة قسم الهندسة المدنية / كلية الهندسة جامعة كربالء جامعة كربالء جامعة كربالء mailto:shakerfa2003@yahoo.com mailto:masaasta@yahoo.com mailto:aljawadola@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 74 الخالصة من المالحظ ان نسبة السطح الى الحجم في الخرسانة المستخدمة للطرق عالية, كذلك بسبب الجو الحار في العراق, يكون تغطية . يقر هذا البحث نتائج دراسة لحصول على خواص هندسية عاليةاالخرسانة بعد عملية الصب مهمة لضمان انضاج فعال, و بالتالي ) مادة بولمراتية(, ومادة ناتج sbrا بمحاليل. وهذا المحاليل هي مادة الستارين بيوتدين ستارين تقيم خرسانة مغطاة سطحي من هذين المحلولين بشكل مفرد او بخليط . عدة محاليل تغطية تم تحضيرها rcعرضي من الصناعة النفطية هي رواسب الخام . تم تقيم sbr, 75% sbr+25% rc, 50% sbr+50% rc, 25%sbr+ 75%rc, 100%rc %100منهما: الخواص الهندسية لنماذج الخرسانة المغطاة و غير المغطاة بمقاومة االنضغاط, مقاومة الكسر و الصالبة وبالطبع وفق متطلبات يوم, بينما نماذج مقاومة 09, 82, 7,,4باعمار لمقاومة االنضغاط لنماذج اتقيم ستخدمة للبالطات الجاسئة . وتم الخرسانة الم يوم. 82الكسر و الصالبة باعمار بالمقارنة مع الخرسانة المتروكة بدون تغطية تحت تأثير sbrو rcطاة بال غوبينت النتائج زيادة ملحوظة في اداء الخرسانة الم ان هناك فروقات ملحوظة ايضا في نتائج االداء حسب نوع المحلول المستخدم. وكنتيجة ملموسة تم اثبات فعالية الجو. كماحرارة مادة ناتجة عرضيا من الصناعة المحلية في تحسين اداء الخرسانة المستخدمة في البالطات الجاسئة كمادة تغطية لالنضاج. abbreviations astm american society for testing and materials aashto american association of state highway and transportation officials bs british institute cdc coated before dry curing dc dry curing rc residue crude sbr styrene-butadiene rubber sra shrinkage reducing admixture wc wet curing 1. introduction the surface to volume ratio of concrete pavement is large. however, in hot weather climate countries (such as iraq), the need for providing supplementary protection to concrete pavement where the pavement panels are in early curing age is well appreciated, as the final engineering characteristics essentially related to. excessive early-age evaporation will lead to insufficient water that required for completing the hydration process. moreover, this could result in plastic shrinkage and cracking of the pavement surface, consequently low strength and durability, corrosion of steel, and loss of pavement service life (ye et al., 2010, american concrete institute, 2001). actually, one part water to 24 parts cement by weight is required during the earlier 7 days instead of the depleted mixed water due to hydration process(american concrete institute, 1997). two methods are used broadly as curing methods in highway pavement constructions; namely, supplying additional moisture by continuous application of water, or minimizing the water loss by either sealing or covering the concrete surface. however, excessive research works have been done to demonstrate the advantages and disadvantages of each curing method. curing the pavement panels by continuous application of water (which is commonly used in local pavement construction) proved unsatisfactory, as the retention of water could be partially, furthermore, this curing method result in a low wear-resistance of the pavement surface(scripture, 1942). on the other hand, burlap or insulating blankets respected as ideal curing method for retaining heat and moisture, but intensive labor and time is required(wang et al., 2006). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 74 significant number of studies have been conducted on the effectiveness of sealing materials. for example, wang et al. were found that the curing effectiveness is highly depends on the time of application and the generic type of the curing membrane (wang et al., 1994). other study conducted by ibrahim et al. proved that the bitumen-based showed best performance as a curing compound in contrast to coal tar epoxy, acrylic-based or water-based materials(ibrahim et al., 2013). in addition, they stated that initial period of water curing before curing compound is applied, could be beneficial in improvement of concrete durability. whiting and snyder investigated the effectiveness of high volatile organic compounds, low volatile organic compounds, plastic sheet and convectional lab water curing, on concrete strength and permeability(whiting and snyder, 2003). the results of mentioned study demonstrated, firstly, that all curing method is significantly better than no curing method in improving the strength and reduce the permeability of concrete. secondly, great difference between different curing compounds is also found, in other words, it is not just sealing. the results of other attempt by dang at el. indicated that a double-coating by shrinkage reducing admixture (sra) can clearly minimize the drying shrinkage and moisture loss of concrete(dang et al., 2013). furthermore, water absorption rate and chloride penetration of the tested concrete are reduced noticeably. the same results were proved by other research studies as well (saliba et al., 2011, folliard and berke, 1997, bentz, 2006). 2. research aim and scope the present research work is aimed to investigate the effectiveness of a two curing compound materials on mechanical properties of concrete use for highway pavement. the first compound is a by-product material, which was selected as environmental friendly and cost effectiveness alternative for the available curing compounds, i.e. residue crude (rc). while, another acrylicbased compound widely utilized in concrete construction was selected for the following reasons:  to minimize the rc dark color; it is believed that there is an essential relation between darkness of exposed surface and the sunlight absorption by the concrete surface, consequently, the rate of evaporation and the fresh concrete temperature.  to minimize the rc viscosity; as shown in figure 1 that incorporating sbr within rc, reduce the viscosity significantly, and consequently facilitate the application of such coating material in normal ambient temperature. 3. research methodology 3.1 materials and specimens preparation the concrete mix used for the experimental program was compatible to the concrete specified by the iraqi requirements for concrete of highway pavement(state orgnization of roads and bridges, 2003). table (1) shows the mix constituents that used to prepare the cubs and prism specimens. at least, three concrete cubes, or three prisms were prepared for each property variation. all the specimens constituents were satisfied the said requirements regarding gradation, so3 content, soundness, material passing 200, etc. styrene-butadiene rubber (sbr) was utilized in the form of emulsion. table (2) shows the physical properties of the sbr. where table (3) shows the properties of rc which was received from aldura refinery plant as a by-product from distillation of crude oil. 3.2 curing protocols three curing protocols were adopted in this study, consequently, three groups of specimens prepared to test after the specified curing periods, i.e. 3,7 ,28, and 90 days. all the specimens in the al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 three groups left, initially, in the mold for 24 hours before de-molding and subjected to the classified curing protocol. however, first group specimens (wet curing, wc) immersed in water curing tank, while, second group specimens (dry curing, dc) left outside the lab directly under ambient weather conditions. the third group specimens (coated before dry curing, cdc), where the specimens coated with curing solutions before subjected to cure outside the lab under the ambient weather condition. five coating solutions were prepared from rc and sbr, individually and collectively; i.e. 100% sbr, 75% sbr+25% rc, 50% sbr+50% rc, 25%sbr+ 75%rc, and 100%rc. these curing solutions applied, firstly, to the upper face of specimen after 30 min of concrete casting, as can be seen in figure (2), and then the other faces were coated after the de-molding 24 hours period to concrete casting. table (4) illustrates the details of curing protocols and coating solutions. 3.3 test methods concrete characteristics are frequently determined in mechanical and durability terms. compressive strength and modulus of elasticity, and less repeatedly, tensile strength, shrinkage and creep are used as mechanical properties. where, carbonation and chloride penetration resistance, and less repeatedly, water absorption and air/oxygen permeability are used to define durability. on the other hand, abrasion resistance is very rarely studied, comparatively; as the property is important in a special concrete part such as dams, spillways, pavement and floor where erosion action is expected (de brito, 2009). in this research work, the influence of covering solution on the properties of hard concrete was determined by the following procedures: i. moisture loss: cylindrical specimens 50 mm diameter x 20 mm height were prepared to determine the moisture loss, according to astm c156 (astm, 2005), after 3, 6, 24, 48, 96, 192 and 336 hours of curing and/or application of covering solutions. ii. compressive strength: cubic specimens 100x100x100 mm were prepared to determine the compressive strength, according to bs 1881-116 (british standards institution, 1983), after 3, 7, 28, and 90 days of accomplishment of curing and/or application of covering solutions. iii. flexural strength: prism specimens 40x40x200 mm were prepared to determine the flexural strength, according to aashto t-97 (aashto, 2003), after 28 days of accomplishment of curing and/or application of covering solutions. iv. hardness of surface: cubic specimens 150x150x150 mm were prepared to determine the hardness of the concrete surface using rebound hammer, according to astm c 805 (astm, 2002), after 28 days of accomplishment of curing and/or application of covering solutions. 4. results and discussion moisture loss figure 3 demonstrates the moisture loss of cement mortar specimens coated with different coating solutions. results obviously showed that the most moisture lost occur in the early curing time for all coated specimen types. however, it could be due to a combination of initial hydration process, bleeding and evaporation. furthermore, uncoated specimens (dc specimens) exposed relatively higher loss of water. it is believed that unsealed surfaces demonstrates increment in the probabilities of evaporation from the surface, then, the dried upper portion minimizes the capillaries water from lower portion of the specimen by suction. in contrast, coated specimens (cdc specimens) disclosed significant saving of capillaries water, but with noticeable variation depends on the type of coating solution. however, it is suggested that the ability of the rc to prevent evaporation is more substantial than sbr. it is may be due to natural of the material itself, but also it could be due to the final ability of the material to supply sound thin cover. results of optical microscopy picture suggested that the sbr thin layer showed some fragments, in contrast to al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 rc, which showed a complete homogenous tight layer, as can be seen in figure 4. thus, the hair space between these fragments could be represent evaporation zones. of course the results of loss of moisture reflect the variation in abilities of different solution to save retention water required to continue the hydration process and produce more hydration products, consequently, enhance the mechanical properties of the produced concrete which will be proven hereafter. furthermore, minimizing the loss of moisture reduces the plastic shrinkage and tensile stress which could occur in the surface of the concrete and specially in pavement panels due to volume to surface are ratio (neville and brooks, 2010). 4.1 compressive strength as expected the development in compressive strength of specimens under continuing wet curing showed significant value in contrast to air dry curing without coating, this has been confirmed for all curing ages, as can be seen in figure 5. in other words, the ratio of compressive strength over curing age of wc/ dc ranged from 118164 %, figure 6, which alarms a noticeable reduction in strength in hot and dry weather climate, due to loss of water that necessary for continuation of hydration process. this range reflects the importance of the mention water; the low ratio noted in early ages, then steadily increased between 7 and 28 days, as the free water in the capillaries bleeds and evaporates, after that, slight difference between 28 and 90 days strengths’ values. on the other hand, coating concrete with the mentioned curing solutions offered valuable increase in compressive strength in contrast with uncoated specimens; again, this is confirmed for all curing ages. for all coating solution types, the ratio of strength over curing ages of cdc/dw showed the same trend regarding the development of strength. although rc generally offer a better preservation to hold water in contrast to sbr, but cdc2 specimens’ strength disclosed the higher values, figure 6. however, this proves that the mixture of rc and sbr with high rc value is significant in preserve water in the capillaries of specimens subjected directly under sunlight, which approves the validity of lowering the darkness of the coating solution. it may said that the evaporation of water under direct sunlight is higher either with coating with rc, as the strength result not follow the loss of water test, whereas the loss of water conducted in lab environment. 4.2 flexural strength results of the flexural strength of coated and uncoated concrete prisms at the age of 28 days (average of three results), are illustrated in figure 7. the prisms had been subjected to the same curing protocols that mentioned in table 4. mostly, the flexural strength disclosed the same trend as the compressive strength testing behavior. whereas, wet curing specimen showed the highest flexural strength, where the dry curing specimens showed the lowest; the flexural strength ratio of wc/dc was approximately 160%, as can be seen in figure 8, normally because of the loss of water that required for hydration process. figures 7 and 8 obviously exposed that the high percentage of rc solution added better enhancement to flexural strength of dry curing specimens in contrast to sbr. the improvement in flexural strength ratio (cdc/dc) ranged from 9% with sbr coating solution, and was increased with increase of the percentage of rc up to 75%, where the improvement reached to about 30%. then a reduction associated with specimens entirely coated with rc. the same explanation adopted to compressive strength improvement that mentioned previously might be adopted here as well, whereas the variation in ability of different type of coating solution in preserve the required water could be after the continuity of the hydration process, consequently development in flexural strength. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 4.3 hardness of surface resistance to wear or hardness is a vital characteristic for the concrete used for road purposes. obviously, course aggregates hardness resists most of the abrasion resistance of tires repetitions, but the mortar hardness, simultaneously, represents the complementary skeleton of wear resistance. although within the last 50 years, a numerous researcher tried to find a good relationship between compressive strength and rebound surface hardness, there is a significant diversity still found by proposed models (szilágyi et al., 2011). however, abrasion has to measure by a tool other than compressive strength to represent the characteristics of concrete surface. the test method of rebound number described in astm c805 (astm, 2002) could bring an effective tool to measure the hardness of the concrete that facing vehicle tires, in other words abrasion resistance (dhir et al., 1991). taking in to account the fact that the evaporation and bleeding occurs in the top surface of the concrete panels, normally top lay of concrete panels represents the critical part, which should check. rebound number was determined on three 150x150x150 mm cube concrete samples according to astm c805 principles(astm, 2002), for each coating solutions and dry and wet curing protocol specimens. the results of the rebound number test on concretes are graphically shown in figure 9. it was found that while the maximum rebound number was in wc specimens, the smallest was in dc specimens, which is normal, as the evaporation and bleeding occur at the surface of concrete. this process left the upper layer more permeable and has the lowest retention water that required for hydration process, consequently weaker concrete that reflects less rebound numbers. with respect to dc rebound numbers, cdc1, cdc2, cdc3,cdc4,and cdc5 showed 16%,20%,16%, 12% and 8%, enhancements, respectively, as a result of coating process, as can be seen in figure 10 . the reason for these enhancements could be explained by the verity of different coating solutions to preserve water. however, using these solutions present a development in abrasion resistance in term of rebound number. 5. conclusions from results of this research work, the following can be concluded and recommended: 1. incorporating sbr into rc significantly reduces the produced solution viscosity, which bring a beneficial effect in terms of coating application process. however, the new produced solution can be spread easily over the concrete pavement panels, without heating process. 2. application of coating solutions in hot weather climate, considerably reduce the loss of water and evaporation of the water needed to continue the hydration process in the early age of concrete. 3. over all laboratory test results demonstrated significant improvements in mechanical properties of the concrete that coated in contrast with uncoated air dried concrete, i.e., the compressive strength, flexural strength and hardness increase with range between 8-64% depends on solution type, property type and age of concrete. 4. base on laboratory test results, application of a solution with 25% sbr and 75% rc on concrete demonstrated the best practice for improving the mechanical properties of concrete pavement. these results could be due to the effectiveness of the rc to provide sound layer which prevent the water evaporation, at the same time, the incorporating of sbr help in reduce the darkness of the surface where the absorption of the sunlight less, consequently minimizing the surface layer temperature and the evaporation of the water. 5. results proved that by-product bitumen base material such as rc could produce a respectable and dependable coating compound, either if it use without any treatment or modification, which bring outstanding beneficial impact on quality, environment and cost of produced concrete. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 acknowledgment the authors gratefully acknowledge the production division staff of dura refinery plant for kind help in supplysing the rc. references [1] aashto 2003. standard method of test for: flextural strength of concrete (using simple beam with third point-loading),aashto t-97. american association of state highway and transportation officials,washington,d.c. [2] american concrete institute 1997. guide for concrete highway bridge deck construction. american concrete institute,usa. [3] american concrete institute 2001. guide to curing concrete. american concrete institute,usa. [4] astm 2002. standard test method for rebound number of hardened concrete. c 805, american aociety for testing material, west conshohocken, pa 19428-2959, united states. [5] astm 2005. standard test method for water retention by liquid membrane-forming curing compounds for concrete. c 156, american aociety for testing material, west conshohocken, pa 19428-2959, united states. [6] bentz, d. p. 2006. influence of shrinkage-reducing admixtures on early-age properties of cement pastes. journal of advanced concrete technology, 4, 423-429. [7] british standards institution 1983. bs 1881-116: testing concrete —part 116: method for determination of compressive strength of concrete cubes. london, uk. [8] dang, y., qian, j., qu, y., zhang, l., wang, z., qiao, d. & jia, x. 2013. curing cement concrete by using shrinkage reducing admixture and curing compound. construction and building materials, 48, 992-997. [9] de brito, j. 2009. abrasion resistance of concrete made with recycled aggregates. international journal of sustainable engineering, 3, 58-64. [10] dhir, r. k., hewlett, p. c. & chan, y. n. 1991. near-surface characteristics of concrete: abrasion resistance. materials and structures, 24, 122-128. [11] folliard, k. j. & berke, n. s. 1997. properties of high-performance concrete containing shrinkage-reducing admixture. cement and concrete research, 27, 1357-1364. [12] ibrahim, m., shameem, m., al-mehthel, m. & maslehuddin, m. 2013. effect of curing methods on strength and durability of concrete under hot weather conditions. cement and concrete composites, 41, 60-69. [13] neville, a. m. & brooks, j. j. 2010. concrete technology, london, uk, pearson education limited al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 07 [14] saliba, j., rozière, e., grondin, f. & loukili, a. 2011. influence of shrinkagereducing admixtures on plastic and long-term shrinkage. cement and concrete composites, 33, 209-217. [15] scripture, e. w. 1942. method of curing concrete. [16] state orgnization of roads and bridges 2003. general specification for roads and bridges. ministry of housing and construction, iraq. [17] szilágyi, k., borosnyói, a. & zsigovics, i. 2011. rebound surface hardness of concrete: introduction of an empirical constitutive model. construction and building materials, 25, 2480-2487. [18] wang, j., dhir, r. k. & levitt, m. 1994. membrane curing of concrete: moisture loss. cement and concrete research, 24, 1463-1474. [19] wang, k., cable, j. & ge, z. 2006. evaluation of pavement curing effectiveness and curing effects on concrete properties. journal of materials in civil engineering, 18, 377389. [20] whiting, n. & snyder, m. 2003. effectiveness of portland cement concrete curing compounds. transportation research record: journal of the transportation research board, 1834, 59-68. [21] ye, d., shon, c., mukhopadhyay, a. & zollinger, d. 2010. new performancebased approach to ensure quality curing during construction. journal of materials in civil engineering, 22, 687-695. table (1): concrete mix constituents used to prepare concrete specimens constituent cement content coarse agg. fine agg. w/c unite (kg/m 3 ) (kg/m 3 ) (kg/m 3 ) % value 375 1079 610 0.5 table (2): physical properties of styrene-butadiene rubber (sbr) sp. gr. (20 oc) viscosity (20 c, cp) ph (20 c) total solids (wt%) sbr 0.954 171 9.1 40 table (3): physical properties of residue crude sp. gr. (20 c) viscosity (20 c, cp) flash point ( c) fire point ( c) rc 1.001 2640 140 175 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 00 table (4): details of curing protocols and coating solutions. protocol no. abbreviation before de-molding after de-molding 1 wc 24 hrs. in lab air curing temp. 25± 2 ºc, rh= 50±5 continuous immersing in water path at 20ºc ± 2 tile testing time 2 dc 24 hrs. in lab air curing temp.= 25± 2 ºc, rh= 50±5 continuous air curing out side lab at temp.=34ºc ± 5 , rh=15±5,tile testing ti me 3 cdc1 specimens left to dry for 30 min, then coated the free surfa ce with coating solution (100% rc), after that left for 24 hr s. in lab air curing temp.= 25± 2 ºc, rh= 50±5 coating the other specime n surfaces with coating so lutions, then continuous ai r curing outside lab at tem p.=34ºc ± 5 , rh=15±5,ti le testing time cdc2 specimens left to dry for 30 min, then coated the free surfa ce with coating solution (75% rc+ 25% sbr), after that l eft for 24 hrs. in lab air curing temp.= 25± 2 ºc, rh= 50± 5 cdc3 specimens left to dry for 30 min, then coated the free surfa ce with coating solution (50% rc+ 50% sbr), after that l eft for 24 hrs. in lab air curing temp.= 25± 2 ºc, rh= 50± 5 cdc4 specimens left to dry for 30 min, then coated the free surfa ce with coating solution (25% rc+ 75% sbr), after that l eft for 24 hrs. in lab air curing temp.= 25± 2 ºc, rh= 50± 5 cdc5 specimens left to dry for 30 min, then coated the free surfa ce with coating solution (100% sbr), after that left for 24 hrs. in lab air curing temp.= 25± 2 ºc, rh= 50±5 figure (1): coating solutions viscosity at 25 ºc 2260 106 85.4 52.6 25.4 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 100 %rc 75% rc + 25% sbr 50%rc + 50% sbr 25%rc + 75% sbr 100%sbr v is co si ty ( c p ) coating solution type al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 figure (2): effect of coating solution type on moisture loss of cement mortar 0 0.5 1 1.5 2 2.5 3 3.5 4 0 50 100 150 200 250 300 350 400 450 500 550 600 650 m o is tu re l o ss , (% ) time, (hrs.) dc cdc1 cdc2 cdc3 cdc4 cdc5 a b figure(4): optical microscopy of a) rc, b) sbr figure (2): covering the specimens with curing solutions after 30min of casting al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 04 figure (3): effect of coating solution on compressive strength ratio figure (4): effect of coating solution on flexural strength 1 1 7 .5 1 6 3 .9 1 5 7 .3 1 5 6 .3 1 0 2 .1 1 2 5 .6 1 2 1 .9 1 2 2 .6 1 0 7 .5 1 2 7 .6 1 2 5 .6 1 2 6 .7 1 1 0 .9 1 1 9 .3 1 1 7 .7 1 1 7 .1 1 0 8 .5 1 1 7 .3 1 1 1 .8 1 1 3 .1 1 0 6 .4 1 1 2 .4 1 0 9 .0 1 1 2 .3 100 110 120 130 140 150 160 170 3 7 28 90 c o p m re ss iv e s tr e n g h t ra ti o ,( % ) curing time, (days) wd/dc cdc1/dc cdc2/dc cdc3/dc cdc4/dc cdc5/dc 4.66 2.91 3.62 3.78 3.46 3.33 3.19 0 1 2 3 4 5 wc dc cdc1 cdc2 cdc3 cdc4 cdc5 f le x u ra l st re n g h t, ( m p a ) coating solution types 1 7 .3 3 2 .1 3 8 .7 4 0 .8 1 4 .8 1 9 .6 2 4 .6 2 6 .1 1 5 .1 2 4 .6 3 0 .0 3 2 .0 1 5 .9 2 5 .0 3 0 .9 3 3 .1 1 6 .4 2 3 .4 2 8 .9 3 0 .6 1 6 .0 2 3 .0 2 7 .5 2 9 .5 1 5 .7 2 2 .0 2 6 .8 2 9 .3 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 3 7 28 90 c o m p rs iv e s tr e n g h t, ( m p a ) curing time, (days) wc dc dcd1 cdc2 cdc3 cdc4 cdc5 figure (5): effect of coating solution on compressive strength al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 04 figure (5): effect of coating solution on flexural strength ratio figure (6): effect of coating solution on rebound number figure (7): effect of coating solution on rebound number ratio 160.1 124.4 129.9 118.9 114.4 109.6 100.0 110.0 120.0 130.0 140.0 150.0 160.0 170.0 wd/cd cdc1/cd cdc2/cd cdc3/cd cdc4/cd cdc5/cd f le x tu ra l s re n g th r a ti o , (% ) coating solution types 35 25 29 30 29 28 27 20 22 24 26 28 30 32 34 36 38 40 wc dc cdc1 cdc2 cdc3 cdc4 cdc5 r e b o u n d n u m b e r coating solution types 140.0 116.0 120.0 116.0 112.0 108.0 100.0 105.0 110.0 115.0 120.0 125.0 130.0 135.0 140.0 145.0 150.0 wd/cd cdc1/cd cdc2/cd cdc3/cd cdc4/cd cdc5/cd r e b o u n d n u m b e r ra ti o , (% ) coating solution types مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 161 التوجه نحو الجودة واالعتمادية في التعليم المعماري قسم هندسة العمارة في الجامعة التكنولوجية انموذجا 4102ايلول 0 ق بل في 4102نيسان 14ستلم أ مستخلص البحث : هندسة هندسة العمارة محليا من خالل اعتماد قسم برامج تعليمهذا البحث هو محاولة لبناء نموذج لتطوير مع ن اداء القسم لكي تتالءم مخرجاتهلغرض تطوير وتحسي. العمارة في الجامعة التكنولوجية كعينة للدراسة احتياجات سوق العمل ومتطلبات خطط التنمية . أي باتجاه تصميم منظومة تطوير مستندة على العناصر .الرئيسة لتحقيق الجودة واالعتمادية العالمية منظومة تستوفي تقويم اداء برنامج التعليم المعماري مصممة وفق رؤى لنماذج وضع حاولت هذه الدراسة جراءات اعتماد برامج التعليم معالتقويم في عدد من التجارب في الدول العربية ، االستفادة من معايير وا م برنامج التعليم المعماري في الواليات المتحدة األمريكية . فقد تم وضع اسس فكرية لتصميم المنظومة لتقوي و تمثلت في الجوانب العلمية ، االدارية ، المنهجية العملية.؛ المعماري في العينة المختارة عبر حلقات ثالثة حسب طبيعة البرنامج التعليمي ونوع التقويم وأهدافه. واالعتماد على اهم المقترحات المقدمة في سبيل تطوير جة الفعلية لخريجي القسم في سوق العمل ، وذلك في ضوء المنهجيات منهجية التعليم بما يتماشى مع الحا الحديثة المتبعة في عملية التصميم المعماري وبرامج تحقيق الجودة واالعتمادية العالمية. مقترح لوضع مقياس تقييمي عام يعزز ويدعم برامج الجودة والتقييم الذاتي للعملية التعليمية هو هذا البحثو أكثر من كونه دراسة نقدية لهذه األقسام .داخل األقسام المعمارية عموما ، والتنظيمية أ.م.د. ابراهيم جواد كاظم ال يوسف / رئيس القسم بغداد -الجامعة التكنولوجية ibrahimc4_11@yahoo.com حداد / عضو هيئة تدريس م. م. احمد طالب حميد بغداد –قسم هندسة العمارة / الجامعة التكنولوجية a_talib11@yahoo.com م. د. عبد اهلل سعدون سلمان / عضو هيئة تدريس بغداد –قسم هندسة العمارة / الجامعة التكنولوجية abdullah.asadoon@yahoo.com mailto:ibrahimc4_11@yahoo.com mailto:ibrahimc4_11@yahoo.com مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 162 towards quality assessment in architectural education cause study : architecture engineering in university of technologyiraq abstract this study is attempt to design development model for architectural education and it's about the process of development of architectural engineering departments in iraq to improvement performance to arrive appropriate outcomes for work market and planning of development , in the other word to implement first step to quality assurance. this study not for critique departments of architectural engineering but it is try to design a system for development can be defined as a yardstick to evolution of development process designed according to new design methods and quality assurance programs in arabic area and usa standard for architectural education . this system consist of three rings : first ring : management sides . second ring : the scientific sides of architectural profession. third ring : the applied sides for method of the development. keywords: architectural methodology, architectural education, quality assurance مقدمة حث اإلسالم على بناء مجتمع قوي متماسك من خالل اإلتقان واإلخالص في العمل، وتنمية الرقابة الذاتية تحقيقًا للجودة في أداء األعمال. وكثير من اآليات القرآنية الكريمة تعزز االلتزام بالجودة واإلتقان في العمل العبرة ليست بكثرة و ، 88ي َأْتَقَن ُكلَّ َشْيٍء ...( سورة النمل/ اآلية بدافع إيماني، قال تعالى ) ... ُصْنَع اللَِّه الَّذِ العمل بقدر ما هو بحسنه . قال تعالى: ) الذي خلق الموت والحياة ليبلوكم أيكم أحسن عمال وهو العزيز لخيص يتقنه(، يمكن تالغفور(. وجاء في الحديث الشريف) إن اهلل يحب إذا عمل أحدكم عماًل صالحا أن ة في مفردة واحدة ) اإلحسان ( ومن هذه الكلمة صاغ علماء العصر والمشتغلون بعلم الجودة تعريف الجود .تعريفاتهم في تنميةة مجتمعاتهةاال تستطيع ان تسهم ألنهاان مؤسسات التعليم ال تعزل نفسها عن المعايير العالمية للجودة بيئتها الثقافية . معللخدمات التعليمية بما يتالئم بدون وجود برامج رقابية على كفاءة تقديمها اهتمةام الكثيةر مةن العةاملين فةي حقةل كةل اختصةاص هندسةي وأهدافةهيثير التعليم الجامعي بنظمه ولوائحةه حيث تمةةايز فيةةه فصةةل التعلةةيم المعمةةاري عةةن التعلةةيم الهندسةةي فةةان هنةةاك ففةةي الوقةةت الةةذي يصةةعب، ( ومنهةةا العمةةارة) . تتبةع كليةات الهندسةة على المستوى المحلةي العمارةف .ليم العمارة كفن وعلم متكاملين ومندمجينتعل وخصوصية وحاجةةة الخاصةةة والعامةةةفةةي ضةةوء حاجةةة الدولةةة ومؤسسةةاتها ومؤسسةةاته التعلةةيم المعمةةاري وعنةةد مراجعةةة اليةةات assistant prof.dr. ibrahim j.k. alyousif / dean of arch. engineering ibrahimc4_11@yahoo.com assistant lecturer msc./ ahmed talib h. haddad / department of arch. engineering a_talib11@yahoo.com lecturer dr. / abdullah.sadoon / department of arch. engineering abdullah.asadoon @yahoo.com mailto:ibrahimc4_11@yahoo.com mailto:a_talib11@yahoo.com مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 163 ار فةي مةدى فائةدتها االختبة علةى محةكواليةات التعلةيم المقةررات الدراسةيةالسوق من المعمةاريين يضةع الكثيةر مةن بمةةا يخةةدم ةالعمةةار هندسةةة دراسةةة آلليةةات تطةةوير أقسةةام لواقةةع الحيةةاة والممارسةةة العمليةةة ، االمةةر الةةذي يسةةتدعي مةةن وذلةةك ، وتنميتهةةا الطلبةةة المتقةةدمين لدراسةةة هةةذا التخصةةص للتعةةرف علةةى قةةدراتهم مةةن مواهةةب هندسةةية وفنيةةة باألسةتاذ والطالةب والمةنهج والبنةى اور العمليةة التعليميةة ) الممثلةةتراعي معظةم محةمنظومة تطوير خالل وضع احدث المناهج التصميمية ومعايير الجودة العالمية . لتتوافق معمصممة التحتية واالنظمة االدارية ( على الجانب المعرفةي ، تستند بشكل مباشرdevelopment methodologyواستعان البحث بمنهجية للتطوير المةنهج ( وعالقةتهم بةالمجتمع . لةذلك سةتكون –الطالةب –جه الفكري لعناصر العملية التعليمية ) االستاذ أو التو عملية التصميم عملية نشاط ذهني وحوار فكرى تتحاور فيه قةدرات الطالةب والتدريسةي بصةورة عضةوية تسةتوعب اضافة الى االهتمام بمكونةات يل البصري ،التعبير المعماري المنطوق المرتبط بالمفاهيم والمرسوم المرتبط بالتمث تحديد حيز المشكلة ) وهو منظومة التطوير المقترحة ( ضمن بيئة العملية التصميمية ومعرفة نتائجها من خالل افتراضية تضم االهداف المعمارية ) كالجمالية والوظيفية واالنشائية والخدميةة والبيئيةة االخةرى المقومةة للمشةروع مكانةةات اإلنتةةاج الصةةناعي ) المعمةةاري ( وحاجةةات المجتمةةع ) التةةي قةةد تعكسةةها الجهةةات المسةةتفيدة احيانةةا ( ، وا .البنى التحتية من مباني و اثاث ووسائل تعليمية ( منهج البحث  اختيةةار قسةةم مةةن خةةالل ) محليةةا (التعلةةيم المعمةةاري نةةامجبر تطةةوير وضةةع اطةةار عةةام ل : اهميةةة البحةةث ) المبنيةة علةى الدقةة وذلك نظرا للطبيعة العلمية التطبيقيةة ، نموذجا امعة التكنولوجية في الج هندسة العمارة .العلميةاالدارية و ، وبسبب معايشة الباحثين لبيئته والتقييس العلمي ( لتوجهات هذه الجامعة  وير عدم وجود دراسات تطةوير مباشةرة لمنظومةة التعلةيم المعمةاري محليةا فضةال عةن تطة :مشكلة البحث قسم هندسة العمارة في الجامعة التكنلوجية تأخذ بنظر االعتبار التوجه نحو الجودة واالعتمادية العالمية .  لالعتمةاد ( اسةتراتيجي طةارإل تصةور أو )منظومةة تصةميم مةن خةاللاطةار نظةري بنةاء : البحث هدف محليةا ة العمةار هندسةة أقسةام تطةوير( ل كمقترح عام ) قابل للمراجعةة حسةب التوجهةات الخاصةةوضبط الجودة وذلك باالستفادة مةن محةوين االول : دراسةة اهةم المحةاوالت العربيةة لتطةوير نظةم التعلةيم المعمةاري ، والمحةور .ية عموما والمعمارية على وجه خاصالثاني : دراسة اهم المعايير العالمية في مجال تقييم البرامج التعليم منظومةةة عمةةل مقترحةةة أكثةةر ممةةا هةةو دراسةةة تبحةةث فةةي بيةةان مةةدى وضةةعهةةو هةةذا البحةةث لةةذلك فهةةدف يعةةزز ويةةدعم بةةرامج ) مقتةةرح (مقيةةاس تقييمةةي بنةةاءسةةلبية أو ايجابيةةة قسةةم معمةةاري بعينةةه ، أي انةةه مقتةةرح ل . الجودة والتقييم الذاتي للعملية التعليمية والتنظيمية داخل األقسام المعمارية مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 164  : ن تطةةوير وتحسةةيل 1اعتمةةاد قسةةم هندسةةة العمةةارة فةةي الجامعةةة التكنولوجيةةة كعينةةة للدراسةةة عينةةة الدراسةةة تصةميم منظومةة باتجةاه أي . مع احتياجات سوق العمل ومتطلبةات خطةط التنميةة لكي تتالءم مخرجاته هاداء مةةةاريين مع اعةةةداد مةةةن خةةةالل .العالميةةةة مسةةةتندة علةةةى العناصةةةر الرئيسةةةة لتحقيةةةق الجةةةودة واالعتماديةةةةتطةةةوير architectural، واالبةةةةداع المعمةةةةاريknowledgeمتميةةةةزين، لهةةةةم القةةةةدرة علةةةةى الجمةةةةع بةةةةين المعرفةةةةة creativityوالوعي الهندسي ، engineering awareness.  حات البحثمصطلاهم : o ( فةةي معجمةةه لسةةةان العةةرب كلمةةةة الجةةودة بةةةأن أصةةلها جةةةود 4881 حسةةةب ابةةن منظةةةور): الجةةودة الةةرديء، وجةةاد الشةةيء جةةوده، وجةةوده أي صةةار جيةةًدا، وأحةةدث الشةةيء فجةةاد والتجويةةد مثلةةه وقةةد والجيةةد نقةةيض .أي أتى بالجيد من القول والفعل جاد جوده وأجاد والجةودة . تحقيةق احتياجةات وتوقعةات المسةتفيد حاضةرًا ومسةتقبالً بانهةا عبةارة عةن)ديمةنج( الجودة حسبو تأدية العمل على نحو صحيح مةن الوهلةة األولةى لتحقيةق الجةودة أنها بيكي معهد اإلدارة الفيدرالي االمر حسب المرجوة بشكل أفضل وفعالية أكبر في أقصر وقت، مع االعتماد على تقديم المستفيد مةن معرفةة مةدى تحسةن (. 1144) يحياوي ، ء األدا o عليم أكاديمية على مستوى : وهو برنامج متكامل لتعليم مهنة العمارة ضمن وحدة ت برنامج تعليم معماري التعليم العالي في الجامعات العربية . ومكونات هذا البرنامج هي : األهداف ، المدخالت ، البيئةة ، المةنهج .( 4888)فادن واخرون ، ، تنفيذ المنهج ، المخرجات ، مصادر التقويم ، أدوات التقويم o : عملهةةةا علةةةى بعضةةةها طبقةةةًا فةةةيتعتمةةةد لتةةةيا مجموعةةةة مةةةن المركبةةةات واألجةةةزاء هةةةي منظومةةةة التطةةةوير ، وللمنظومةةة بعةةدين احةةدهما أهةةداف محةةددة بعينهةةا المنظومةةة( للوصةةول إلةةىأي لتخطةةيط محةةدد يسةةاعدها ) واالخةةر يمثةةل منهجةةا لعمةةل انظمتهةةا الثانويةةة framework for understandingيمثةةل اطةةار الفهةةم operational systems methodology ي يجمةع بةين المفةاهيم الفكريةة وسةلوكيات او فهي مفهةوم علمة ادراك ، وبالنتيجة فان المنظومة هي لغة شمولية يمكن من خاللها مناهج التكامل والترابط بين تلك المفاهيم وفهةةةم التعقيةةةد اللةةةذان يعةةةدان احةةةدى صةةةفات الواقةةةع المعاصةةةر الةةةذي يعكةةةس محةةةاوالت العلةةةوم الفوضةةةى اجةةةواء حةةل محاوالتهةةا فةةي والعلةةوم االجتماعيةةة فةةي ، chaos الفوضةةى تحديةةد وعةةالم الال الطبيعيةةة فةةي اكتشةةاف الواقع الفكري االنساني على كافة االصعدة االجتماعية واالقتصادية والثقافية وغيرها complexity تعقيدات 1 ( . 8811)الوقائع العراقية ، 8811( لسنة 04ية حسب ما اشار اليه قانون وزارة التعليم العالي والبحث العلمي رقم )يضم القسم ) الذي يعامل معاملة كل ماري فرعا علميا واحدا وهو التصميم المعماري على مستوى الدراسات االولية ، ويضم ثالثة تخصصات عليا على مستوى الماجستير هي التصميم المع كنولوجيا العمارة ، باإلضافة الى التخصصات الدقيقة لدراسة الدكتوراه .والتصميم الحضري وت على يد نخبة من المعماريين 8811ويعد قسم هندسة العمارة في الجامعة التكنولوجية من األقسام العريقة في العراق ، وبداية تأسيسه كانت في عام ( 3482) تقرير التقييم الذاتي ،من الجامعات المتخصصة بتدريس العلوم الهندسية التطبيقية.العراقيين ضمن كيان الجامعة التكنولوجية التي تعد وزارة التعليم ويمكن للقسم ضمن خطة تطويره االستفادة من الكوادر التدريسية العاملة فيه وما تخوله القوانين السارية ، وكذلك للعمل على تطبيق رؤية ى التخصص في العلوم ، والى فتح فروع جديدة على مستوى الدراسة االولية بحيث تؤهل الطالب للدخول في مرحلة متقدمة العالي ) العراقية (في السعي ال من العملية التعليمية تبعا لقدرات الطالب واحتياجات سوق العمل . مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 165 .(gharagedaghi,2006) واسةةتعان البحةةث بهةةذا المفهةةوم ليعمةةل عمةةل الخلفيةةة النظريةةة التةةي تعكةةس الواقةةع ، .لبرامج التعليمية للتفاعل العناصر المختلفة ) والمتداخلة ( والديناميكي المعقد  وهةةي تتمحةةور بجةةانبين؛ االول يمثةةل اهةةم المحةةاوالت العربيةةة لتطةةوير جةةودة التعلةةيم :الدراسةةات السةةابقة مةذكور فةي المعماري ، والثاني يبين اهم مةا توصةلت لةه منظمةات جةودة التعلةيم المعمةاري العالميةة وهةو مةا على التوالي ، وفي ضوء ذلك حاول البحث ان يكون رؤيته الخاصة لبناء منظومة ( 1( و ) 4الفقرتين ) تطةةوير مسةةتفادا مةةن هةةذه الدراسةةات العربيةةة والعالميةةة مةةع مراعةةاة البيئةةة المحليةةة لتحقيةةق خطةةوط اوليةةة عامةةة ( من هذا البحث . 1تحقق في الفقرة ) التعليم المعماري على المستوى المحلي ، وهذا ماجودة لتطوير على المستوى العربي : تهاجودودراسة برامج التعليم المعماري .2 يمكةةن عةةرض بعةةض المحةةاوالت لنقةةد وتطةةوير بةةرامج التعلةةيم المعمةةاري علةةى المسةةتوى العربةةي مةةن خةةالل بعةةض العتمةاد الجةودة فةي التعلةيم الدراسات لباحثين عرب ، كما يمكن ايضا ان نأخذ بعةض المقترحةات لتصةميم بةرامج الجةةامعي عمومةةا وفةةي التعلةةيم المعمةةاري خصوصةةا تةةم التعةةرض لهةةا مةةن بعةةض البةةاحثين العةةرب ، وكمةةا مبةةين فةةي المحاور التالية : :(1112علي،): للباحث عبد الرؤوف علي داللة اإلبداع في التعليم المعماري 0-0 ، ويكةةةون التسةةةاؤل المشةةةروع ي العمةةةارة والتخطةةةيط الحضةةةريالعمليةةةة التعليميةةةة فةةة يمثةةةل االبةةةداع مكونةةةا رئيسةةةيا فةةةي االبداعيةة الفكةر والقةدرات تنمةي بإمداد الطالب باألدوات والمناهج التةي التدريسيبالكيفية التي من خاللها يتمكن تتجةةاوز انمةةاط التعلةةيم العمةةارة. ومةةن ذلةةك كةةان التوجةةه نحةةو منةةاهج بديلةةة لتعلةةيم علةةى مسةةتوى المفةةاهيم والةةرؤى علةةةى اعتمةةةاد المهنةةةي المحتةةةرف المةةةدعم بالمعرفةةةة سةةةتندت، والتةةةي المسةةةتمدة مةةةن البةةةوزار و الباوهةةةاوس حاليةةةة اال . 1 (4، شكل) انفصاالت ومهنة العمارة في ثالث العمارةتعليم العالقة بين تفسير والمهارات ، و المحتةوى المعرفةي وعمليةة التةدريس لتعليم العمارة يعتمد على ثالث عناصةر هةي امقترح بديال ادد اطار وقد حُ .(1112)علي، المقومات وله مجموعةوأسلوب التدريس ،  الحرفي ومفاهيم فلسفية المهارىالعمارة هي عالقة وتداخل بين التشكيل .  معمةةةاري المسةةةتقبل فةةةي مةةةدارس العمةةةارة لكةةةي يةةةتفهم دوره فةةةي اطةةةار المجتمةةةع المحلةةةي واإلقليمةةةي اعةةةداد والعالمي. 1 كان المعماري متواجدا في موقع البناء مسؤوال عن عملية المعماري ال يبني ولكن العامل والحرفي يبنون، حتى نهاية العصور الوسطى االنفصال االول : عندما حدث االنفصال االول بين العمارة والبناء ، عندما انشأ كولبرت مدرسة العمارة االولى التي سميت االكاديمية الملكية 8714انتاج المبنى حتى عام من المدرسة المتخصصة ، وتركت مهمة البناء للعامل. للعمارة، وأصبح المعماري ال يستقبل المعرفة من الموقع بل يتلقاها ضمور سيطرة المعماري على عمليات البناء، بعد قرنين من انشاء االكاديمية اسست مدرسة الفنون الجميلة لدراسة العمارة في فرنسا عام االنفصال الثاني : لي ، وأصبحت القدرة على انتاج لوحات الواجهات الملونة هي الممارسة للعمارة تفرغ فيها المعماريون لتصميم تكوينات متميزة بمنطق جمالي تشكي 8188 في حدود . ومن ثم حدث االنفصال الثاني عندما ضمرت سيطرة المعماري وانقسمت عملية االبداع في العمارة الى مرحلتين: االولى يمارسها المعماري اء واإلنتاج . مرحلة التصميم والثانية فقدان السيطرة على مرحلة البن الممارسة النظرية للعمارة تنشر وال تبنى، بعد ثالث قرون من انشاء كولبرت ألول مدرسة معمارية، انتشرت مدارس العمارة عالميا، االنفصال الثالث : للعمارة ومهدت لالنفصال الثالث وهو وصيغت كلمة النظرية ككلمة دالة ومؤثرة، واليوم يمارس العديد من االجيال المعمارية ما يسمى بالممارسة النظرية النتاج المعماري النظري المنشور بديال عن النتاج المبني الحقيقي. مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 166  القةةدرة علةةى دمةةج الدراسةةات والمعةةارف الةةبسةةاب الطاك فةةي ءة االطةةر البديلةةة لتعلةةيم العمةةارةم كفةةايتقيةة المختلفة.  الطالب ومساعدته في تحويل حصيلة ثورة المعلومات وتةدفقها المةذهل التدريسي في سد حاجةمسؤولية العمارة.رصيد معرفي مؤثر على العملية االبداعية في التعليم الى  التصميم.والقطاعات المستفيدة من مشروع المتلقي التفاعل مع  عطةةاء انعكةةاس مفهةةوم ومةةنهج التفكيةةر العةةالمي والفعةةل المحلةةي علةةى مفةةاهيم التعدديةةة المعرفيةةة والثقافيةةة وا .الفرصة للطالب للتعرض الحيوي لما يحدث في العالم بالتحليل والتفكير والتأمل ثم التطبيق  كمفهوم تصميمي مؤثر تأكيد مفهوم التنمية المستدامة. :(1112)ه: للباحث هشام جالل ابو سعدتعليم التصميم المعمارينموذج 0-4 مةةن قةةدراتهمان التعلةةيم عمليةةة موجهةةة لهةةا هةةدف فةةي نقةةل المعةةارف الةةى اشةةخاص محةةددين بقصةةد تنميةةة وفةةي مجةةال التصةةميم .)الطالةةب(متلقةةي نظريةةة وتطبيقيةةة. لهةةا قطبةةان المرسةةل)المعلم( وال محةةددة ةيةةمجةةاالت معرف ، شةةةرط اال تتعةةةارض فةةةي التعلةةةيم جةةةاه ومةةةنهج وفكةةةر مختلةةةفاتالتدريسةةةين المعمةةةاري يكةةةون لكةةةل مجموعةةةة مةةةن : (1112)هابو سعد االتجاهات مع القدرات واإلمكانات الموجودة عند الطلبة ومنها  ( رةاتجاه المناقشة والحوار)المنةاظdebate، المةنهج المةنظم المبنةي علةى تعلةيم بإتبةاعتعلةيم طريقةة التفكيةر التفكيةر امةا طةرقبداع من خالل االوتعليم بجانب تطوير المهارات تسلسل عملية التصميم وفق خطوات محددة م التصميم.تعلم اتباع المنهج العملي في تعلوهنا تعد العمارة علما فنيا وعلى الم المواهب والمهارات فتابع لها.  اتجاه التعليم بالتلقينprompt نقل المعلومات الى الطالب دون ترك مسةاحة للتفكيةر، وهنةا يكةون الطالةب ، علةى القةدرةو يمكنةه مةن الةتعلم عةن طريةق التفكيةراطار محدد من الةوعي ليس لهاما غير قادر على التفكير او .الفنون وأساسياتتعلم الطرز  االبتكةةار ألجةةل، وتطةةوير المهةةارات التفكيةةر وتةةراكم المعلومةةات اسةةلوب مةةن خةةاللالتصةةميم المعمةةاري تعلةةيم تةةداخل اربةةع واالبتعةةاد عةةن التقليةةد والمحاكةةاة. ومةةن هنةةا يتحقةةق االبةةداع فةةي مجةةال التصةةميم المعمةةاري مةةن خةةالل . ، المهارات، وطريقة التفكيرالمواهب، عملية التلقين: دوائر كل منها يمثل عنصرا من عناصر االبداع مبتكةربةين المقصةود مةن ماهيةة االبةداع فةي الوصةول الةى شة فةي العمةارة يمكةن توضةيح االخةتالف ومما تقةدم، االبةةداع وبةةين التصةةميم الةةذي هةةو عمليةةة يمكةةن مةةن خاللهةةا تحقيةةق ذلةةك. وكةةال ،يلبةةي االحتيةةاج ويمةةس المشةةاعر ، المعاصر الواقع وأساسياتكل معايير الى تطبيق باإلضافة، مليتان متالزمتان في اطار موضوعيوالتصميم ع مراحةةةل، مقسةةةما النمةةةوذج الةةةى ثالثةةةة اإلبةةةداعالتعلةةةيم المعمةةةاري معتمةةةدا علةةةى مفهةةةوم مةةةن خةةةالل بنةةةاء نمةةةوذج ، (.1شكل) مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 167 وقةد تةم اختيةار ثةالث حةاالت دراسةية ذات عالقةة تعليم العمارةتصميم نموذج لتقويم فاعلية اداء برامج 0-3 ( :4888، واخرون هيكل) و ( 4888واخرون ، )فادن مباشرة بالموضوع ، وتمثل ثالث مستويات هي مفهةةوم التطةةوير الشةةامل المسةةتمر علةةى هنمةةوذج عةةام ، وهةةو نمةةوذج تقةةويم اعتمةةد فةةي تصةةميم المسةةتوى االول : لتقةةةويم البةةةرامج ويسةةةاعد علةةةى تحسةةةين االداء لعملياتةةةه. ويميةةةل الةةةى النظةةةر الةةةى البرنةةةامج كونةةةه منظمةةةة متكاملةةةة. امج في : سياق محتوى ، مدخالت ، عمليات تنفيذ ، ومخرجات البرنامج. وللنموذج اربعة محاور هي تقويم البرن مقيةاس تقةويم فاعليةة بةرامج التعلةيم الجةامعي االكاديميةة ، فقةد حةدد تصةميم عناصةر ومصةادر المستوى الثاني : . 1لعربيةوأدوات مقياس شامل يمكن استخدامه لتقويم فاعلية مكونات برامج مؤسسات التعليم الجامعي في البيئة ا تقويم برنامج التعليم المعماري ، باعتماد شروط و اجراءات اعتماد برامج التعليم المعماري في المستوى الثالث : التةي سةيتم اسةتعراض جانبةا ( .naabالواليات المتحدة االمريكيةة / المجلةس الةوطني العتمةاد التعلةيم المعمةاري) بحث .( من هذا ال 4-1منها فيما بعد في الفقرة ) . ( 2 شةةةكل )وباالستفادة من المستويات الثالثة توصال الى بناء نموذج لتطوير وتقييم التعليم المعماري وضةبط الجةودة فةي الجامعةات الةى ان االعتمةاد اشار ( 1141) الخطيب : وضبط الجودة يةاالعتماد 0-2 ت ومعةايير التميةز والشةفافية وضةبط الجةودة ، قد ارتبط برؤية تمثلت في توفير تعليم عةال وفقةا لمواصةفاالعربية :مواجهة التحديات المستقبلية جاذبة وداعمة لإلبداع لوتهيئة بيئة تعليمية  المةةةوارد ،الطةةةالبة، المؤسسةةةي األهةةةداف: استقصةةةاء المعةةةايير التةةةي تسةةةتخدمها معظةةةم هيئةةةات االعتمةةةاد .واإلدارة ،الهيئة التدريسية ، المناهج،المكتبة ومصادر المعلومات واألجهزة،المرافق المادية ، المالية  تشةةخيص جوانةةب الخلةةل والقصةةور ومنهةةا : التفةةاوت والتةةداخل فةةي عةةدد المعةةايير فةةي المجةةاالت المعتمةةدة فتقار الى الشةمولية والحداثةة واالفضال عن نقل او تقليد معايير من تجارب اخرى ؛ لالعتماد وضبط الجودة ، وعدم مواكبة هذه النماذج للتغيرات والتطورات. ،ضبط الجودةلر المعتمدة التداخل بين المعايي ،والتنظيم  قةام الخطيةب بتطةوير انمةوذج لالعتمةاد وضةبط الجةودة واعتمةادا علةى منحةى ولمعالجة هذه االشةكاليات ، البةةةرامج ،الحاكميةةةة والتنظةةةيم ،، ويتكةةةون مةةةن المجةةةاالت التاليةةةة : الرؤيةةةة والرسةةةالة واألهةةةداف(1ل)، شةةةكالةةةنظم ،المرافةةق والتسةةهيالت والخةةةدمات ،مصةةادر الةةةتعلم والمكتبةةات وتكنولوجيةةا المعلومةةةات ،التعلم والتعلةةيمتربويةةة،لا والمخرجات. ،الرقابة والمساءلة والتقويم،التمويل ،البحث العلمي :الدولية واالعتمادية برامج التعليم المعماري .1 : 2(naab) األمريكيالمجلس الوطني العتماد التعليم المعماري 4-0 1 ، محتوى البرنامج وأساليب تقويم االداء التدريسي ، اساليب تقويم البرنامج ، مصادر جعنصرا موزعة على ابعاد : اهداف البرنام 71احتوى المقياس . [7]ويم. التقويم ، وأدوات التق 2 the national architectural accrediting board (naab), الموقع االليكتروني http://www.naab.org http://www.naab.org/ http://www.naab.org/ مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 168 وهي مؤسسة امريكية غرضها وضةع معةايير تمثةل الحةد االدنةى لمواصةفات الخةريج الةذي لةه حةق ممارسةة المهنةة في الواليات المتحدة االمريكية لذلك فان معظم المؤسسات التعليمية هناك تخضةع لهةذه المعةايير لغةرض السةيطرة تمثلةةت فةةي ثالثةةة عشةةر ضةةعها تلةةك المؤسسةةةت هنةةاك عةةدد مةةن المعةةاييرو علةةى جةةودة مواصةةفات خةةريج العمةةارة . (naab,2008) .(5شكل) ،معيارًا ، و ثالثة مستويات من االجراءات وهي عبارة عن إطار شامل لتقويم فاعلية برامج التعليم المعماري لتضمن تحقيق مستوى تعليمي مهني جيد يؤهل مةةن اليةةات المتحةةدة العتمةةاد شةةهادة خريجهةةا و بهةةا أي مؤسسةةة تعليميةةة فةةي الو وتلتةةزم الخةةريجين لمزاولةةة المهنةةة ، تمفقةرة ية 21، والمؤلةف مةن student performance criteria (spc)هةو معةايير اداء الطالةب أهمهةا (naab,2008)ي برنةةةامج تعليمةةةي غرضةةةه اعةةةداد معمةةةاري مؤهةةةل فةةةي الواليةةةات المتحةةةدة االمريكيةةةةألاسةةةتيفاءها :وهي ، الرسةمية االلتةزام بالضةوابط، مهةارات بحثيةة الرسم ، مهارات الناقد ، ارات التفكير مه ، مهارات القراءة والكتابة ، التقاليةةد غيةةر الغربيةةةدراسةةة ، التقاليةةد الغربيةةةدراسةةة ، العمةةل التعةةاونيمهةةارات ، مهةةارات التصةةميم االساسةةية التنةةةوع دراسةةةة ، السةةةلوك االنسةةةاني دراسةةةة، االسةةةتفادة مةةةن التجةةةارب السةةةابقة، التقاليةةةد االقليميةةةة والوطنيةةةةدراسةةةة االنظمةة ، ظةروف الموقةع، الةوظيفي البرنةامجاعداد ، التصميم المستدام ، امكانات الوصولدراسات ، االنساني تكامةةل انظمةةة ، انظمةة الخةةدمات المبةةاني، انظمةةة تغليةةف المبةةاني، سةةالمة الحيةاة، االنظمةةة البيئيةةة، االنشةائية التصةميم الشةامل، دور الزبون في العمةارة، الوثائق الفنية ، مراقبة تكلفة البناء، د البناءمكونات وموا، المباني االحكةةةام ، المسةةةؤولية القانونيةةةة، القيةةةادة، التطةةةور المهنةةةي، الخبةةةرة المعماريةةةة، دور ادارة المهنةةةدس المعمةةةاري، ت االنجةاز : االول ، مسةتوى الفهةم ؛ والثةاني المعايير بمستويين مةن مسةتويا هذه ترتبطو . المهنية واألخالقية ، مستوى التطبيق . أكاديميةة مهنيةة يمكةن أخةذها معةايير( naabتضةمنت شةروط المجلةس الةوطني العتمةاد التعلةيم المعمةاري ) وقةد :تتلخص ، (4888 ،هيكل) في االعتبار  ( ، وتشةةةمل الشةةةروط : االعتمةةةاد ) خاصةةةة بنظةةةام التعلةةةيم الجةةةامعي األمريكةةةي األوليةةةة التأهيليةةةة لمعةةةاييرا اإلقليمةةةي ؛ تةةةوفر وحةةةدة أكاديميةةةة معتةةةرف بهةةةا ؛ مةةةنح درجةةةات علميةةةة معتةةةرف بهةةةا مثةةةل درجتةةةي البكةةةالوريوس والماجستير ؛ احترام المسئوليات األخالقية  التقةةةةويم الةةةةذاتي وقيةةةةاس فاعليةةةةة بةةةةرامج التعلةةةةيم المعمةةةةاري ، وتشةةةةمل الشةةةةروط : التقةةةةويم الةةةةذاتي ؛ معةةةةايير لمنظةةور الدرجةةة المهنيةةة فةةي 1تيفاء متطلبةةات الخطةةة الدراسةةية ؛ تحقيةةق توجهةةات المجلةةس الةةوطني لالعتمةةاداسةة 1 وهو ما تهتم به ، ليم والطالب التع: التعليم والبيئة األكاديميةتحتوي تحقيق توجهات المجلس الوطني لالعتماد لمنظور الدرجة المهنية في العمارة ويكون aiasالجمعية األمريكية لطلبة العمارة ) هو ما تهتم به الهيئة الوطنية األمريكية لمجالس التسجيل المعماري ) ، التعليم والتسجيل المعماري ؛ ( ncarb والذي تهتم به جمعية المعماريين األمريكية ) ، التعليم ومزاولة المهنة ؛ ( aiaa . ) مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 169 والتعليم ومزاولة -والتعليم والتسجيل المهني -والتعليم والطالب -التعليم والبيئة األكاديمية : العمارة وتحتوي . 1المهنة ؛ واستيفاء متطلبات اإلنجاز الموجه لألداء  مصةةةةادر ؛ المصةةةةادر المكانيةةةةة ؛ المصةةةةادر البشةةةةرية روط اإلمكانةةةةات البيئةةةةة األكاديميةةةةة ، وتشةةةةمل : شةةة الموارد المالية ودعم المؤسسة .؛ و إثراء الفرص ؛ المعلومات : abet 2 منظومة قياس جودة المؤسسات التعليمية الهندسية في مؤسسة 4-4 ، الطلبةةة ، البةةرامج التعليميةةة ، الكةةوادر التدريسةةية ، دارةإلامحةةاور لتقيةةيم المؤسسةةات التعليميةةة هةةي abetتضةةع البنةةةى التحتيةةةة ) القاعةةةات والمختبةةةرات والتجهيةةةزات والوسةةةائل التعليميةةةة والخدميةةةة االخةةةرى ( ، والمةةةوارد الماليةةةة . :فيهاعايير االعتماد الرئيسة . وتتلخص ممج االكاديمي الهندسي معيارا لمواصفات خريج البرنا 44اضافة الى  وضع اهداف للبرنامج التعليمي و تخطيط لعملية التعليم ال اهمية.  متابعة لخريج المؤسسة ومدى نجاح االهداف الموضوعة للبرنامج التعليم.  مدى قيام المؤسسة بعملية التطوير والتحسين المستمر لبرنامجها التعليمي. لةةيم الهندسةةي لةةيس فقةةط مةةن خةةالل امتحانةةات فةةي قيةةاس مخرجةةات بةةرامج التع abet( يوضةةح اليةةة 2والشةةكل ) اربةةاب العمةةل سةةتبياناتالخةةريج وابيانات الطلبةةة بةةل مةةن خةةالل سةةلوك الطالةةب اثنةةاء الدراسةةة وبعةةد تخرجةةه مةةن اسةةت ومعرفة المهارات التي استطاع الطالب ان يكتسبها مةن البرنةامج التعليمةي ويطبقهةا بعةد تخرجةه فةي ميةدان العمةل (lim & elt, 2012). ، وذلةةك مةةن (riba)البريطةةاني للعمةةارة الملكةةي تقيةةيم التعلةةيم المعمةةاري اعتمةةادا علةةى المعهةةد ايير معةة 4-3 ، خةةةالل مراحةةةل الدراسةةةةوالتطبيقيةةةة والذهنيةةةة تزويةةةد الطالةةةب بالمهةةةارات المعرفيةةةة آلليةةةاتخةةةالل مصةةةفوفة متكاملةةةة ، للعمةارةا المعهد الملكةي البريطةاني مقارنة بمصفوفة االحتياجات العامة لمتطلبات المهنة المعمارية التي يطرحه يحةةدد المعهةةد الملكةةي البريطةةاني مجموعةةة معةةايير رئيسةةة لقيةةاس مةةدى اسةةتيعاب او ادراك الطالةةب للمةةواد العلميةةة و :(riba,2003) والعملية ألجل حصوله على المعرفة المعمارية ، موضوعة ضمن خمسة مصفوفات رئيسة هي  التصميمdesign.  البيئة التكنولوجيا وtechnology & environment .  الثقافة cultural context .  االتصالcommunication .  ادارة العمل والقانونmanagement practice & law . 1 عنصراً موزعة على المجاالت األربعة ، حيث يمكن قياس تلك العناصر بناًء على مستوى اإلنجاز الذي يحققه الطالب عند تخرجه من 23ع المجلس وض ) خالل: الدراية أو الوعي awareness ( ؛ الفهم ) understanding ( ؛ القدرة أو المهارة ) ability . ) 2 accreditation board for engineering and technology, http://www.abet.org هي مؤسسة تديرها مجموعة جمعيات علمية مهنية 12 قبلعالمية في الواليات المتحدة هدفها اعتماد المؤسسات التعليمية في المجال الهندسي على مستوى الواليات المتحدة والعالم ، تأسست عاما http://www.abet.org/ مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 170 ألجةل الحصةول علةى البةورد الملكةي البريطةاني فةي العمةارة part1, part2 , part3ثالثةة اجةزاء ذلةك فةيو لعملية التعليم فةي كةل هةذه المعةايير هةي مستويات راه عمارة ، ويفترض ان هناك اربعة يعادل احيانا دكتو الذيو وهةو القةدرة والفهةم وتعنةي التحديةد الةدقيق للمعلومةة بكافةة جوانبهةا ، والمعرفةة ، المجال المعرفي ب، الوعي الشامل ختيةار المعلومةة المناسةبة وتطبيقهةا الةربط بةين المفةاهيم المعرفيةة ، والتطبيةق وهةي القةدرة علةى ا وعلى االسةتنتاج .(riba,2003)لحل مشكلة محددة : مناقشة اليات التطوير .3 والجودة واالعتمادية الدولية يمكن مناقشة مكونات منظومة التطوير في ظل التوجه العام لبرامج التعليم المعماري : (4)جدول اكدت عليها هيالتي يمكن االستفادة منها في استنتاج مجموعة محاور ) سابقة الذكر (  : كمةةا اكةةدت عليهةةا مؤسسةةات االعتمةةاد العالميةةة مثةةل االدارة والتنظةةيم المخطةةطnaab وabet و riba ، والتةةي تشةةمل وضةةع االهةةداف وادارة القةةدرات البشةةرية والماديةةة والماليةةة والمعلوماتيةةة ، كمةةا موضةةح ( وفةةادان 1141الةةى نمةةوذج الخطيةةب ) باإلضةةافة مةةن هةةذا البحةةث . 2-1و 1-1و 4-1فةةي الفقةةرات . 1-4و 2-4في الفقرات ( 4888و ) ( 4888وهيكل )  : التي تهتم بوضع برنامج تعليمي مالئم للطالب وفق اهداف ورؤية استراتيجية واضحة الجوانب العلمية ، 2-4و 1-4و 4-4المعالم ، كما قد اكدت عليهةا بعةض نمةاذج التعلةيم المعمةاري العربيةة فةي الفقةرات باإلضةةةافة الةةةى معةةةايير مةةةع مراعةةةاة اختيةةةار التدريسةةةي المناسةةةب ، والقةةةدرة علةةةى اعةةةداد تدريسةةةي المسةةةتقبل . naab وabet وriba .  : التةي تجمةع بةين المحةورين السةابقين مركةزة علةى اختيةار الطلبةة وتطةوير الجوانب التطبيقية المنهجية م المعمةةاري ومتابعةةة انضةةباط الطالةةب ، وتفعيةةل دور اللةةوائح ، مةةنهجهم الدراسةةي ومنهجيةةات تعلةةيم التصةةمي باإلضةةافة الةةى االهتمةةام بةةالبنى التحتيةةة والوسةةائل التعليميةةة للمؤسسةةة التعليميةةة كمةةا قةةد اقرتهةةا ايضةةا الفقةةرات وتفرعاتهما في هذا البحث . ( 1 ) و( 4 ) ، ومعايير نمةوذج فةادان ) naabمعايير اعتمادية التي نالحظ فيها هيمنة في ضوء هذه المعطيات المستنتجة الث وذلةةةك بةةةةث ، التطةةةوير المقترحةةةةمنظومةةةةة ليةةةات آبعةةةض جوانةةةب إلةةةةىنشةةةير ممةةةا سةةةبق يمكةةةن ان ( ، 4888 ) االولى؛ الجوانب االدارية والتنظيمية، والثانية؛ الجوانب العلميةة والثالثةة؛ الحوانةب مستويات او حلقات مترابطة 1 مع محيطيها الفكري والمادي . تتفاعلواحدة كمنظومة ل بعملها مع بعضها البعض تتكام المنهجية( : والتنظيمية اإلداريةالجوانب : األولىالحلقة 3-0 وتتميةز بالمرونةة ومجةارات التطةور وتضم مجموعة من النقاط المهمةة التةي يجةب التركيةز عليهةا بهةذا الخصةوص : ( 4 ) انظر جدول والتي يمكن حصرها بالتالي 1 تمثله عادات وتقاليد وثقافة المجتمع العراقي المسلم ) كأكثرية غالبة ( والمناهج الدراسية للقسم. محيطها الفكري ، ليمية( .ومحيطها المادي ، تمثله ثالثة عناصر مهمة هي ) الطالب + التدريسي+ البنى التحتية المتمثلة بالمبنى واألثاث الهندسي والوسائل التع مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 171 األخةةةرى وفةةةق خطةةةة والمعلوماتيةةةة تخطةةةيط وتنظةةةيم ومراقبةةةة الكةةةوادر البشةةةرية والماليةةةة والماديةةةة 3-0-0 (. 4-1-3المبين في الفقرة ) استراتيجية مكتوبة ومعلنة في سبيل تحقيق الهدف الرئيسي للقسم ، مةةن ذوي االختصةةاص سةةياالعتمةةاد علةةى الخبةةرات العلميةةة بالمجةةال اإلداري والتنظيمةةي والتدري 3-0-4 حتى ولو تطلب األمر استقدامهم من جامعةات أخةرى فةي اثبتوا جدارة مشهود لها في ذلك )بمجال عملهم والذين مواكبةةللتغييةر والتطةوير و السةاندةإطار التعاون وتبةادل الخبةرات( ، واالعتمةاد علةى الكةوادر اإلداريةة والتنظيميةة change ofلعةالم المتحضةر اليةوم يبحةث فةي مصةطلح تغييةر التغييةر. فاالتقةدم العلمةي فةي مجةال التخصةص change وال يقف عند حدود التغيير فقط ؛ تلبية لمتطلبات المجتمع وحاجاته ، (evans,1983). ، العاملةة بالمجةال االداري او التدريسةي علةى االسةاس العلمةي المةرتبط ضرورة تقييم الخبرات العلمية 3-0-3 .ق قبل اعتماد اي اساس اخر ، لكي تتم عملية انتقاء موضوعي للكفاءة العلمية بالعطاء والتطبي لكفةةاءات العلميةةة ، وتفعيةةل ذلةةك فةةي تقيةةيم امبةةدأ الثةةواب والعقةةاب الالنتقةةائي ومنهةةا ، االدارة بالمبةةاديء 3-0-2 م تفعيةل العمةل للقضةاء علةى أي ترهةل إداري أو تنظيمةي بسةبب عةد و (sonnenberg , 2011)لتحفيز المنتسبين بهذا المبدأ ، أو االنتقائية بتطبيقه. وضةةع لةةوائح معلنةةة لعمةةل الكفةةاءات العلميةةة فةةي القسةةم ، مةةع مراعةةاة القيةةام ، لةةوائإ اداريةةة تنظيميةةة 3-0-5 بتنقيحها وتطويرهةا بمةا يةتالئم مةع معطيةات التقةدم العلمةي العةالمي ، ومةن خةالل ذلةك يعةرف كةل تةدرج اداري او ياته ، وصالحيات غيره في اتخاذ القرار ، وتوضيح تلك اللوائح من خةالل وضةع دليةل للتدريسةي تنظيمي صالح ودليل للطالب ودليل للقسم. الجوانب العلمية في مجال االختصاص :الحلقة الثانية : 3-4 : (4) انظر جدول الفقرات وتضم التطورات العالمية ، واكبةوالديناميكية في م أيضاوهي تتميز بالمرونة تمثةل العمةارة مةرآًة لحضةارات وثقافةات الشةعوب لةذلك التعليميةة : واألهةداف الرسةالةالرؤيةة و تحديةد 3-4-0 فةةي (1112، علةةي) األساسةةيةفةةي تةةدريس المقةةررات اإلسةةالميةتعكةةس الثقافةةة العربيةةة أهةةدافايةةتم تبنةةي أنالبةةد لمقةرر التصةميم ، المسةاندة الدروس النظريةة اف تلك االهدعزز تُ أنويجب وخصوصا مقرر التصميم ،، القسم الشكل المعماري العالمي المعاصر والنظريات الحديثة في هذا المجال . علىالتطورات الحاصلة إهمالمع عدم المجتمةعبنةاء نمةط تصةميمي يلبةي المتطلبةات الثقافيةة واالجتماعيةة لهويةة محاولةة يكةون هةدف القسةم هةو بذلكو ثانيةا ، ثةم المجتمةع التةي ينتمةي لهةا هةذا اإلسةالميةثةم متطلبةات الثقافةة العربيةة أوالته المحليةة ضمن بيئ لعراقيا بناء المناهج الدراسية للقسم . أثناءمتطلبات التقدم الثقافي العالمي المعاصر ثالثا ، تخصةةص لتشةةعب االختصاصةةات التةةي تةةدخل ضةةمن ال :توسةةيو وتحةةديث قاعةةدة البيانةةات االساسةةية 3-4-4 : العلمي لقسم هندسة العمارة ، فان هناك جانبين يتم العمل بهما وتحةةديث عنةةاوين مصةةادرها العلميةةة ، و تزويةةدها بالةةدوريات العلميةةة عةةن طريةةق المكتبةةة مثةةلي الجانةةب االول : ن وبالتعاو ؛كفاءة علمية في مجال المكتبات ذويمختصين تطلب وجودي االمر الذي كتب التخصص الحديثة ، .عربية وعالمية مع مكتبات اتصالهاو طرق العلمية بتحديثها ال إلتباع الكادر التدريسيمع مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 172 االشتراك مع مواقع بيةع الكتةب : عن طريقاالنترنت تصال بشبكة المعلومات العالمية تعزيز اال: الجانب الثاني ي وات للتعةةةاون و التبةةةادل االلكترونةةةفةةةتح قنةةة؛ و مات المكتبةةةة االفتراضةةةية العراقيةةةةاالسةةةتفادة مةةةن خةةةد؛ و العالميةةةة ضةةةةمن موقةةةةع الجامعةةةةة القسةةةم تعزيةةةز وتطةةةةوير موقةةةةع مةةةةع . عالميةةةةا وعربيةةةةا للمعلومةةةات مةةةةع الجامعةةةةات األخةةةرى . يكون نافذة القسم وواجهته على العالم لالترابط بين األستاذ والطالب و لتسهيلالتكنولوجية ، فةةةي تةةدريس الطلبةةة لتجنةةةب ، التخصةةص العةةةالي الةةدقي التركيةةع علةةةى الكاةةاءة العلميةةةة فةةي مجةةةال 3-4-3 .1العمومية بالتدريس حتةى فصةلية خاصةة بالقسةم أونشرة علمية شةهرية تأسيس، ان بناء قاعدة بحثية معرفية معلوماتية 3-4-2 مختصةةين مةةن جامعةةات أسةةاتذةعالميةةا باتصةةالها مةةع ، ولهةةا اثرهةةا تكةةون نشةةرة محكمةةة علميةةا أن، مةةع محاولةةة .2 للتدريسيينينة ، وذلك لتطوير الجوانب العلمية رص المواضةةةيع المعاصةةةرة ، أهةةةمتنةةةاق تنظةةةيم النةةةدوات والمةةةؤتمرات العلميةةةة ل :نةةةدوات ومةةةؤتمرات علميةةةة 3-4-5 العةراق التطوير والتغيير العلمي بما يخص العمارة فةي أو، العمران العمارة و اع واقعية قطمشاكل لوتضع الحلول مةرت منةاهج التصةميم الهندسةي فعلةى سةبيل المثةال :فةي الوقةت الحاضةر ي يحتاج الةى دعةم وتعزيةزالذ األمر، ومةؤتمرات مجموعةة طةرق 4821ومةؤتمر بورتسةموث 4825ومؤتمر بيرمنكهام 4821بالعالم من مؤتمر لندن علمةي منهجةي دقيةق كبرى نقلت الفكر التقليدي للتصميم الى فكرعمليات تغيير بالتصميم األمريكية في كمبردج (jonse,1981) . (dmg)في مؤتمر جماعة طرق التصميم 4811في عام أخرىنقلة نوعية إلىمناهج التصميم بعدها انتقلت الهندسةةةية وطةةةرق معالجةةةة المشةةةكلة لألفكةةةار المرونةةةة وقابليةةةة التغييةةةر عوامةةةل إدخةةةالخةةةالل هةةةذا المةةةؤتمر تةةةم فمةةةن مكانيةةةحةةل المشةةكلة التصةةميمية لسةةيكولوجيةر النفسةةي الةةذي سةةمح للتفسةةي األمةةر؛ التصةةميمية متطلبةةات إدخةةال وا آفةةاقفةةتح إلةةى أدىوهةةذا ،العوامةةل االجتماعيةةة والثقافيةةة المتغيةةرة كإدخةةالالعمليةةة التصةةميمية أثنةةاءقابلةةة للتغييةةر . (heath,1984) تشعب وتغيير في حل المشكلة التصميمية أكثر القسم : لتطوير العملية واآللياتنهجية الجوانب الم: الحلقة الثالثة 3-3 : ( 4) انظر جدول وتتضمن عدد من الفقرات هي ، يةتم فيهةا التركيةز علةى النوعيةة عتماد اسس علمية ووضو امتحانات كاةاءة الختيةار الطلبةة الجةددا 3-3-0 . وليس الكمية وفة خطةة شى مو التطورات العالميةةقسم العمارة بما يتما ومواد ومارداتة الدراسي خطةتطوير ال 3-3-4 من خالل: استراتيجية 1 فير هذه الكفاءة من العناصر المحلية عن طريق تبويب وتنظيم عملية إرسال البعثات العلمية بتخصصات يطلبها القسم فعال وعدم الركون إلىومحاولة تو لى انتقاء افة إرغبة طالب البعثة في تحديد االختصاص ، وهذا له األثر الكبير في تطوير القسم ووضع األسس العلمية المستقبلية السليمة لبنائه ، باإلض . العناصر ذات االختصاص العالي الدقيق من غير المحليين والمحافظة على العناصر الكفوءة منهم 2 وهو متحقق في القسم فعال من خالل المجلة الفصلية العلمية المحكمة التي يصدرها " المجلة العراقية لهندسة العمارة " مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 173  الى النظام الفصلي الذي يتم تطبيقه اآلن في معظم جامعات لتقليديتطوير النظام الدراسي السنوي ا .مع مراعاة دروس التصميم المعماري كدروس تقييم مستمر خالل السنة العالم  تفاعةل مةع هةذه المسةتجدات التطبيقيةة ، ومرونةة وضع مةنهج دراسةي وفةق تخطةيط اسةتراتيجي تفصةيلي ي استقبال المستجدات العالمية. يعرضةةون تجةةاربهم فةةي مجةةال ، معمةةاريين عةةالميين وعةةرب ومحليةةينمةةو فةةتإ دوائةةر للنقةةا الحةةر 3-3-3 العمةةةةةل ، واالسةةةةةتفادة مةةةةةن مقترحةةةةةاتهم لتطةةةةةوير العمليةةةةةة التعليميةةةةةة وتقريبهةةةةةا مةةةةةن ارض الواقةةةةةع والمجةةةةةال العملةةةةةي طالعةهوتفعيل هذا الجانب له اثر كبير في ترغيب الطالب باختصاصه ، تصاص.لالخ أسةاتذةومناقشةته مةع وا ذه بهةة تةةأثراممكن الطالةةب مةةن بنةةاء شخصةةيته تليةة األخةةرىالهندسةةة المعماريةةة فةةي بلةةده أو بلةةدان العةةالم وأسةةاطين مجةال العمةارة يثةري الجانةب المهنةي خبةرة فةي ذوي أجانةبان اسةتقدام معمةاريين . كمةا مهمةال معماريةالرموز ال .هيئة التدريس ألعضاءوالتدريسي مقةررات التصةةميم ضةمن: منةاهج تصةةميمية حديثةة فةي التعامةةل مةو المشةكلة التصةةميمية اعتمةاد 3-3-2 لتطةةور ل مواكبةةةً وكةةذلك بسةةبب تةةأثيرات المتطلبةةات االجتماعيةةة المتغيةةرة علةةى التصةةميم ، ،المعمةةاري والحضةةري اسةةةلوب التةةةدريس مةةةع تطةةةوير والثةةةورة الرقميةةةة المعاصةةةرة ،الهائةةةل الةةةذي يشةةةهده القةةةرن الحةةةادي والعشةةةرين التقنةةةي اسةةلوب التقيةةيم الفةةردي المحصةةور بأعضةةاء الكةةادر التدريسةةي و المعتمةةد علةةى النقةةد الةةداخلي بةةين الطالةةب واالسةةتاذ فةةي االبةةداع وفةةق ضةةوابط ومحةةددات الةةى اسةةلوب اكثةةر انفتةةاح يةةربط الطالةةب بةةالواقع ويةةدع لةةه الخيةةار ، الةةداخلي قةةةد لغةةة التعامةةل مةةع المشةةكلة التصةةميمية وذلةةك الن مدروسةةة بعيةةدا عةةن اسةةلوب التلقةةين والخيةةارات المحةةدودة . أصةبحت (rittel, 1984) التصةميم جيةل جديةد مةن طةرقظهةور ب الماضةي مةن سةبعينيات القةرن ابتةدءاتغيةرت فقةةةط ، وال علةةةى التحليةةةل العقلةةةي الرياضةةةي األسةةةودلصةةةندوق طريقةةةة حةةةل المشةةةكلة ال تعتمةةةد علةةةى الحةةةدس وافيةةةه بالمشةةةكلة ؛ فلةةةم يعةةةد المتةةةأثرين األطةةةرافالنقةةةا المفتةةةوح بةةةين جميةةةع أسةةةلوبوالصةةةندوق الزجةةةاجي ، بةةةل تعتمةةةد هندسةةةي يستشةةةير ويشةةةرك المسةةةتخدم للمنةةةتج ال أصةةةبحيصةةةمم المنتجةةةات الهندسةةةية ؛ بةةةل المصةةةمم جالسةةةا بمكتبةةةه .ا يتخذهبالقرارات التي األمةةر التعلةةيم المعمةةاري أسةةاليببقةةوة علةةى أثةةرتهةةذه التطةةورات المهمةةة فةةي عمليةةة حةةل المشةةكلة التصةةميمية ان فةةي أخةةرى آفاقةةا، وفةةتح ة هندسةةة العمةةار م اقسةةاالقةةديم المتبةةع فةةي تغييةةر الواقةةع التدريسةةي التقليةةدي ع نحةةو يةةدف الةةذي طةةورات العلميةةة بهةةذا المجةةال ، والتةةي اقلهةةا هةةو اسةةتخدام الت آخةةر إلةةىتعلةةيم الطالةةب للحلةةول التصةةميمية باالسةةتناد أثنةاء ينواختصاصةيين حقيقيةين متلقةأسلوب التعامةل مةع لطالب في حل المشكلة التصميمية وتعليم اجديدة طرق عالقات عمل تسمح بالتعاقد مع المؤسسات الحكوميةة والخاصةة بإقامة الجامعة قياموذلك عن طريق ، التصميم والخبةةةةراء المتلقةةةةيمهمةةةةة الطالةةةةب فةةةةي معالجةةةةة المشةةةةاكل التصةةةةميمية علةةةةى الواقةةةةع بتفاعلةةةةه مةةةةع لغةةةةرض تسةةةةهيل رسة جديدة ومد ألسلوبالذي يؤسس األمر ، (david & etl ,2000) في مجال العمل اآلخرينواالستشاريين تةرح لةذلك يةتم تةدريس، وكمقالتقليةدي األسةلوب إهمةال، مةع عةدم بحاجة البيئة المحليةةمرتبط في التدريس المفتوح الصفي ، مع بعةض التطعةيم التقليديوالثانية باالعتماد على النسق األولىمادة التصميم المعماري في مرحلتيها مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 174 فةةي المرحلةةة الثالثةةة ، لتةةةتم فةةي المةةرحلتين الرابعةةة والخامسةةةة تةةزاوج متكامةةل فةةةي التصةةميم الجديةةةدةطةةرق بأسةةلوب وهةذا .فةي تةدريس مقةررات التصةميم فةي القسةم ديث مةن طةرق التصةميمالتطبيق بةين النمةوذجين الكالسةيكي والحة فةةي تقسةةيمه للمسةةتويات الثالثةةة للتعلةةيم المعمةةاري علةةى المراحةةل ( 1112)قريةةب ايضةةا مةةن مقتةةرح ابةةو سةةعده منةذ المرحلةة االولةى cadالةى ضةرورة ادخةال بةرامج التصةميم بمسةاعدة الحاسةوب باإلضةافة الدراسية الخمسة . التخيلية الواسعة التةي يوفرهةا الحاسةوب لتطةوير واألفاقالى الخامسة لخلق التكامل المطلوب بين ذهنية المصمم اليةةةة التعامةةةل مةةةع االشةةةكال التصةةةميمية والفراغيةةةة فةةةي التصةةةميم ، مةةةع الضةةةرورة الملحةةةة فةةةي السةةةيطرة علةةةى ادراك المعمةةةاري ونظريةةة االسةةةقاط بصةةةورة مزامنةةةة لعمليةةةة ادراكةةةه للتكوينةةةات الطالةةب فةةةي المراحةةةل االولةةةى لعمليةةةة الرسةةةم ، فالدراسات الحديثة في مجال التعليم المعماري تركز المعمارية من خالل التصميم بمساعدة الحاسوب واألشكال علةةى اهميةةة اعةةداد مصةةمم معمةةاري ذو قةةدرة عاليةةة فةةي معالجةةة المشةةكالت التصةةميمية مةةن خةةالل التركيةةز علةةى لةةول المتكاملةةة واهمةةال الحلةةول الناقصةةة مةةع القةةدرة علةةى اعةةداد الحلةةول البديلةةة المتعةةددة بةةدل الحةةل الواحةةد وفةةي الح مةةن خةةالل مةةنح الطالةةب قةةدرة المرونةةة والمنةةاورة وتعةةدد الحلةةول زمةةن قياسةةي ، واهميةةة مسةةاعدة الحاسةةوب فةةي ذلةةك . ( tokman &etal ,2007)التصميمية والمفاضلة بينها في زمن قياسي ادارة وتنظةيم شةؤون الطلبةةالقصةوى فةي ألهميتهةا، وذلةك الدراسة واالمتحانات لوائإ وقوانينتاعيل 3-3-5 ، مع عدم اهمال تطويرها لتتماشى مع اللوائح الرصينة لبعض الجامعات المعتبرة عالميا. مةةن خةةالل اعةةداد غةةرف وذلةةك تةةوفير البيئةةة المريحةةة لعمةةل االسةةاتذة والكاةةاءات العلميةةة فةةي القسةةم 3-3-6 كان يكون هناك اثاث مكتبي مناسب. مريحة لهم تتوفر فيها اجواء عمل تتماشى مع اختصاصهم ، رسةةم لوحةةات وذلةةك مةةن خةةالل وجةةود قاعةةات مكيفةةة ، و دراسةةته أثنةةاءللطالةةب الجاذبةةةتةةوفير البيئةةة 3-3-7 جديةةةدة فةةةي التصةةةميم أسةةةاليبتعلم لوضةةةع الطالةةةب بةةةالجو المناسةةةب ، ليةةةتم بعةةةد ذلةةةك تكليفةةةه بةةة ، مخصصةةةة لةةةذلك الوتطوير مستواه ، لضةرورة وجةود إضةافة، التطةوير سةابقة الةذكر آليةاتمجمةل تعةاني مةن القصةورسوف وا طريقةةةة التصةةةميم إدخةةةالضةةةرورة و . حاسةةةوب متخصةةةص ختبةةةر صةةةنع النمةةةاذج ، وممختبةةةر لمعمةةةل متخصةةةص الةذي سةيؤدي األمةرالعمةل بهةا إتقةانالطالةب علةى ، وتةدريبالخاصةة لةذلك األجهةزةالمحاكةاة واسةتيراد بأسةلوب اجهةزة صةنع البيئةة االفتراضةية والمحاكةاة هةي مةن إن. زيادة مدركات الطالب وسهولة توصةيل المعلومةة لةه إلى البيئةةة أجهةزةوتتمثةل ، ابةرز مةؤثرات الثةورة الرقميةة فةي القةرن الحةادي والعشةةرين علةى منةاهج التصةميم المعمةاري حاسةةةوب و بةةةرامج أجهةةةزةإلةةةى إضةةةافةبوجةةةود شاشةةةات عةةةرض مسةةةتديرة أو منةةةاظير محاكةةةاة للحركةةةة االفتراضةةية مجةةةاراة احةةةداث التطةةةور التقنةةةي يحةةةاولومةةةن ذلةةةك ، فةةةان القسةةةم . cad .(whyte,2002)مسةةةاعدة التصةةةميم العةةةةالمي فةةةةي مجةةةةال الحاسةةةةوب وتقنيةةةةات ووسةةةةائل التعلةةةةيم الحديثةةةةة كاللوحةةةةات الذكيةةةةة ومختبةةةةرات الحاسةةةةوب ذو ( تبةةةين واقةةةع حةةةال قسةةةم هندسةةةة العمةةةارة فةةةي الجامعةةةة 1والصةةةور فةةةي الشةةةكل ) . 1المواصةةةفات التقنيةةةة العاليةةةة 1 وتكامل اندماج برامج المساعدة في التصميم بعملية التدرج في ادخال الحاسوب القسم باشر cad في تدريس مواد التصميم المعماري الرئيسة ،لحين استكمال التجربة لمراحل اخر. في المرحلة االولى ، باعتماد لغة الحوار والتفهيم بورش متخصصة اضافة الى الدروس الساندة سوب التابعة للقسم للسيطرة على نوعية المشاريع.اجراء معظم اعمال االطروحة التصميمية في مختبرات الحا وجود أجهزة الكمبيوتر مع العارضات االلكترونية الخاصة بها ، وذلك لتطوير أساليب التدريس وخلق نقلة نوعية كبيرة في أسلوب توصيل المعلومة للطالب وأساليب استقبال الطالب للمعلومة من جهة أخرى. مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 175 التكنولوجية بعد تحديث البنى التحتية له ، وفتح مختبرات حاسوب متخصصة لغةرض البةدء بعمليةة دمةج التعلةيم بمساعدة الحاسوب مع التعليم التقليدي . :بناء منظومة التطوير .4 لقد اثارت المناقشة ) سابقة الذكر ( وبرامج التعليم المعماري التي تطرقت اليها، افكار وحلول ساعدت على تركةز علةى ربةط ، دراسةة العينةة المختةارة مةن خةالل وضةع منظومةة للتطةوير تركةز علةى ثالثةة منظومةات ثانويةة ( بمعةةايير تطةةوير اداريةةة واخةةرى علميةةة وثالثةةة المةنهج –االسةةتاذ –عناصةر العمليةةة التعليميةةة الثالثةةة ) الطالةةب تطبيقية ) او منهجية ( تصنف كما في ادناه : محاولته لبناء واعي لمنظومة تطوير مؤلفة من ثالثة حلقات أو منظومات ثانوية، هي: 2-0 منظومةة تطةوير اداري تنظيمةي ، وهةذا مةا تةم توضةيحه فةي مناقشةة اليةات التطوير)الحلقةة االولةى( الفقةةرة 2-4. منظومة تطوير علمي تخصصي ، وهذا ما تم توضيحه في مناقشة اليات التطوير)الحلقةة الثانيةة( الفقةرة 2-1 . -2منظومة تطوير اليات العمل ، وهذا ما تم توضيحه في مناقشةة اليةات التطوير)الحلقةة الثالثةة( الفقةرة 2. الثالثة ضمن بيئتين فكرية ومادية: الثانوية تتفاعل المنظومات 4-1 يئة فكرية ، تضم جانبين: جانب ثقافي وحضاري عاما يعكس قيم المجتمع العربةي اإلسةالمي ؛ وجانةب ب تخصصي يمثل المقررات والمناهج المعدة للتعليم . بيئة مادية أساسها الطالب واألستاذ والبنى التحتية للتعليم إلنجاح العملية التعليمية في مجال العمارة . مة التطوير المقترحة ضمن البيئتين الفكرية والمادية . يبين منظو ( 8والشكل) ان عمليةةة التعلةةيم المعمةةاري فةةي هةةذا البحةةث هةةو منظومةةة متكاملةةة مكونةةة مةةن اكثةةر مةةن مفةةردة 2-3 .1معرفية وتنظر لعملية التعليم بنظرة شاملة ( ، مةةن خةةالل 4888اعتمةةد بنةةاء المنظومةةة علةةى تطةةوير فةةي رؤيةةة البةةاحثين هيكةةل وفةةادان ) 2-2 ستخدام منهجية تصميمية اكثر مرونة وانفتاحا ، فاتحا بذلك الطريق نحو دراسات أعمق لهذا الجانةب . فقةد ا مةع تصةميم نمةوذج لتقةويم بةرامج التعلةيم المعمةاري مةن خةالل مقارنةة ( 4888)هيكل و فةادن تعاملت دراسة ت تشابها كبيةرا بينهمةا ؛ لةذلك بين أسلوب تصميم في النموذج التقويمي مع منهجية التصميم المعماري ووجد امةةا منظومةةة التطةةوير فةةي هةةذا البحةةث قةةد نموذجهةةا ألتقييمةةي. وضةةعفةةي التصةةميم منةةاهجاعتمةةدت علةةى عتمةةد علةةى مناقشةة االهةةداف اكثةر مةةن مناقشةتها للخطةةوات المنهجيةةة ياسةتندت علةةى نمةوذج منهجةةي للتصةميم 1 ذج تقييم الجودة العالمية التي تنظر لموضوع التعليم كمنظومة عمل شاملة ومتكاملة ، كما عند مؤسسة اعداد نموذج مقارب لنما abet http://www.abet.org http://www.abet.org/ http://www.abet.org/ مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 176 والطالةب فةي عالقةة تفاعليةة هةدفها ايجةاد وفةاق محاور التطوير والعالقةة بةين االسةتاذ من خالل وضع جميع . واجواء نقا مفتوحة في جو تعليمي واداري وتنظيمي ديناميكي : النتائج -5 قسةةم هندسةةة العمةةارة فةةي الجامعةةة التكنولوجيةةة فةةي ضةةوء حالةةة (، 8والشةةكل)(، 3)يبةةين الجةةدول 2-8 للعةةام الجةةةامعي قهةةا الحاليةةة فةةي القسةةممعةةايير التقيةةةيم ونتةةائج تحقي ألهةةمان يشةةير لةةذان منظومةةة التطةةوير ال الةذي يمكةن مناقشةة (2، جةدول) حلقةةالتقييم لكل مؤشراتمع مالحظات تؤشر وتوثق 3482 3483 :محتوياته في ظل واقع حال القسم فيما يلي  كةةةان وجةةةود المجلةةةة ثحيةةة%( ، 70يةةةة االعلةةةى هةةةي فةةةي واقةةةع حةةةال الجوانةةةب التعليميةةةة )ان النسةةةبة المئو النشةةرة العلميةة الدوريةة والتةةي تنشةر بواقةع مةةرتين فةي السةنة ، مقابةةل تأسةيسلهندسةة العمةارة دليةةل علةى العراقيةة الوجود النسبي الى وضع رؤية وأهداف للبرنامج التعليمي والى تنظيم ندوات لمناقشة مشاكل واقعية.  ؤمن بةالتطوير موجةودة %(. كان انتقاء الخبرات التي تة01)بينما حققت الجوانب االدارية نسبة منخفضة لوائح العمل الداخلية. غياببوضوح مقابل  ( وهةي مقاربةة الةى الجوانةب الداريةة 08) جوانب المنهجية العملية فةي نسةبتها المئويةةفي حين حققت ال% فقةدان النقاشةات الحةرة موجةودة بوضةوح مقابةل توفير البيئةة المالئمةة للطالةب والتدريسةي حين كان في التأثير ، ماريين ممارسين وبارزين.مع مع  ان النسةةبة المئويةةة االسةةتقرائية ) االوليةةة ( لواقةةع حةةال القسةةم مةةن منظومةةة التطةةوير بحلقاتهةةا الثالثةةة هةةي .% وهي نسبة مقبولة نوعا ما 22 % او اكثةر وفةق المعطيةات اعةاله 14النسةبة المئويةة االسةتقرائية الةى ان تصةل الةى نسةبة تعةديل ولغرض من قبةل جهةات خارجيةة محليةة تفعيل دور عمل تقييم الجودة واألداء الجامعي وتحضير القسم للتقييم مع ضرورة ( والتةةةي فيهةةةا يكةةةون التركيةةةز االكثةةةر علةةةى 2 1,2( و)3.3.2(و)3.8.2الفقةةةرات) وعالميةةةة وعمليةةةة تنشةةةيط وعربيةةةة قةةة بالجوانةةب االداريةةة والجوانةةب الجوانةةب المنهجيةةة ، باإلضةةافة الةةى اهتمةةام اكثةةر بحلقتةةي منظومةةة التطةةوير المتعل المنهجيةة العمليةةة وتعزيةةز ودعةةم حلقةةة الجوانةةب العلميةةة خصوصةةا بعةةد وضةةع رؤيةةة واقعيةةة تلبةةي حاجةةات المجتمةةع ( 2.2.2( و)0.2.2( و)2.8.2بالنسةةةبة للبةةةرامج التعليميةةةة المةةةراد فتحهةةةا فةةةي القسةةةم ، مةةةن خةةةالل تفعيةةةل الفقةةةرات ) كمرحلة اولى . واحةةدة ووضةةعها فةةي اسةةتراتيجيةاإلداريةةة والعلميةةة واليةةات التطبيةةق المنهجيةةة كوحةةدة التعامةةل مةةع النةةواحي 5-1 قالب ديناميكي ؛ تم تسميته فةي البحةث باسةم المنظومةة ، وسةبب ذلةك يعةود إلةى تبنةي منةاهج الجةودة واالعتمةاد ر العلمةةي الحةةديث االكةاديمي فةةي تصةةميم منظومةةة التطةوير التةةي تلبةةي متطلبةةات النظةةرة العالميةة المعاصةةرة للتفكيةة ديناميكيةةة مترابطةةة مةةع بعضةةها الةةبعض ومتغيةةرة باسةةتمرار ، وملبيةةة بةةنفس الوقةةت للمتطلبةةات المبنةةي علةةى أسةةس .ع اإلنسانيالثقافية واالجتماعية للمجتم مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 177 ، تبةين عةدم إمكانيةة (2بالجةدول)خالل دراسة متطلبات كل حلقةة مةن حلقةات منظومةة التطةوير المبينةة 5-2 ن هةةذه الحلقةةات الن إهمالهةةا يسةةبب ضةةعفا عامةةا ونقصةةا فةةي أصةةل أي خطةةة تطةةوير مقترحةةة إهمةةال أي حلقةةة مةة ألقسام الهندسة المعمارية . وذلك كون كل حلقة تكون مكملة لألخرى وداعمة لها . ان الطرق الحديثة لحةل المشةكلة التصةميمية ، يمكةن ان تكةون وسةيلة لتطةوير منةاهج حديثةة فةي التعامةل 5-1 المعمةةاري علةةى مسةةتوى سةةتوديو التصةةميم او خارجةةه . وذلةةك لشةةمولية هةةذه الطةةرق وتلبيتهةةا مةةع مشةةاكل التصةةميم للواقع العلمي والثقافي واالجتماعي المتغير والمتطور باستمرار. االستنتاجات : -6 اهمية اعداد خطة استراتيجية علمية لدراسةة ووضةع البرنةامج التعليمةي لكةل فةرع تعليمةي معمةاري ، يأخةذ عتبةةار اهةةم المعةةايير التةةي طرحةةت فةةي بةةرامج التعلةةيم المعمةةاري والجةةودة واالعتماديةةة العالميةةة مةةع بنظةةر اال ، كما قد بينت جانبا منه منظومة التطوير االخذ بنظر االعتبار خصوصية البيئة المحلية ثقافيا واجتماعيا المقترحة في هذا البحث . وانةب االداريةة والعلميةة والتطبيقيةة فةي وضةع الخطةط ضرورة االهتمام وبصورة ترابطية وتكاملية بةين الج الدراسةةية مةةع التركيةةز علةةى نوعيةةة المخرجةةات التةةي يمثلهةةا الخةةريج ومجموعةةة المهةةارات التةةي اكتسةةبها خةةالل دراسته . متابعة المستجدات العالمية والعربية المتسارعة التي تطرأ على تطور التعلةيم المعمةاري واليةات التصةميم ا الحديثة ، ومعايير الجودة العالمية بالخصوص .والتكنلوجي التوصيات : -7 ان دراسة امكانات تطبيق مقترحات منظومة تطوير القسم ، يتطلب تشكيل غرفةة عمليةات تضةم كفةاءات علميةة متخصصةة ، تبحةث كةةل نقطةة بصةورة مترابطةةة مةع النقةاط االخةرى وبصةةورة شةفافة ، وبةدون وجةةود ع المناقشات المستفيضة لذلك ، للخةروج باليةات تطبيةق فعليةة لخطةة التطةوير . اي نوع من انواع الذاتية م مةع ضةةرورة تةوفر صةةالحيات كبيةةرة للمشةرفين علةةى انجةةاح عمليةات تطةةوير جةةذري وتغييةري كبيةةرة ، لتشةةكل هةةذه الحلقةةات الثالثةةة بترابطهةةا لبنةةة اوليةةة مةةن لبنةةات التطةةور المسةةتقبلي والنهةةوض بالعمليةةة التعليميةةة علةةى .توى العراق والعالمين العربي واإلسالمي مس ان نموذج منظومة التطوير المقترحة فةي هةذا البحةث تمثةل اطةارا اسةتراتيجيا عامةا للتطةوير يمكةن ادخةال تفاصةةيل كثيةةرة لكةةل فقةةرة مةةن فقراتةةه باالسةةتعانة ببةةرامج الجةةودة واالعتماديةةة الدوليةةة وباالسةةتفادة مةةن نمةةوذج على سبيل المثال( . من البحث 2-4الفقرة في ري العربية ) مثل نموذج فادانتقويم برامج التعليم المعما مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 178 اطةةةاره النظةةةري مةةةن خةةةالل تأسةةةيسيمكةةةن التوسةةةع اكثةةةر فةةةي المحةةةورين الةةةذي اسةةةتفاد منهمةةةا البحةةةث فةةةي االستفادة من تجارب عالمية واخرى عربيةة اوسةع ، مةع ضةرورة االسةتفادة مةن منةاهج التصةميم فةي تطةوير وير المقترحة . منظومة التط ضةةرورة االسةةتفادة مةةن العمةةارة كتخصةةص متشةةعب الفةةروع واالختصاصةةات لرفةةد سةةوق العمةةل بنوعيةةة مةةن المهندسين االختصاصيين في مجال عملهم . االنةةدماج الكلةةي لبةةرامج المسةةاعدة بالحاسةةوب مةةع االسةةاليب التقليديةةة ، واالسةةتفادة القصةةوى مةةن منجةةزات لتطةةةور التكنولةةةوجي فةةةي مجةةةال الحاسةةةوب وبرمجياتةةةه وفةةةي مجةةةال معرفةةةة المةةةواد الثةةةورة الرقميةةةة العالميةةةة وا النةةةانو كتقنيةةةة مسةةةتقبلية فعالةةةة فةةةي تغييةةةر اسةةةلوب والتكنولوجيةةةات الحديثةةةة فةةةي البنةةةاء مةةةع دخةةةول تكنولوجيةةةا ه التعامل مع المواد واألنظمة االنشائية لتحقيق مضامين العمارة العليةا فةي خدمةة المجتمةع العراقةي وعاداتة وتقاليده . ، اسةةتكمال الدراسةةة التفصةةيلية لمنظومةةة التطةةوير هةةذه ضةةمن اسةةتراتيجية القسةةم وتطبيقهةةا بصةةورة متكاملةةة متوازية مع تطبيق مفردات تقرير التقييم الذاتي للجودة في القسم ، كون هذه المنظومةة تعطةي برنةامج عةام دة االداء ان كةةان حسةةب مؤسسةةة مسةةاعد فةةي كشةةف السةةلبيات وااليجابيةةات فةةي اهةةم محةةاور تقيةةيم جةةو abet او غيرها. ادر:ةةةةةةةةةةةةةةةةةةةالمص . 11( . معجم لسان العرب. الجزء الثاني ، دار المعارف ، القاهرة،. ص. 4881ابن منظور،) (4 ، تعلةةيم التصةةميم المعمةةاري علةةى ضةةوء العالقةةة بةةين عمليتةةي االبةةداع 1112أبةةو سةةعده ، هشةةام جةةالل ، (1 . 2(، مجلد 21-122) 8، مجلة اإلمارات للبحوث الهندسية ، عددوالتصميم ، االعتماد وضبط الجودة في الجامعات العربيةة ، انمةوذج 1141الخطيب ، احمد ، الخطيب ، رداح، (2 .4، طب الحديث للنشر والتوزيعمقترح ، عالم الكت نولوجية ، بغداد .هندسة العمارة ، الجامعة التك، قسم 1142تقرير التقييم الذاتي ، (1 ، مفهوم وداللة اإلبداع في التعلةيم المعمةاري المعاصةر : نحةو رؤيةة 1112، الرؤوفعلي ، علي عبد (5 . aouf.pdfeng.org/uploadfile/uploading/alir-http://arch.arab للنقد ومنهجية للتطوير ، يم المعمةاري ، تصةميم نمةوذج لتقةويم بةرامج التعلة 4888، فادان، يوسف محمد، وهيكل ، نميةر إسةماعيل (2 .2عدد في الجامعات العربية، مجلة اتحاد الجامعات العربية، ، سةبل تطةوير بةرامج التعلةيم المعمةاري فةي 4888هيكل ، نميةر إسةماعيل ، و فةادان ، يوسةف محمةد ، (1 . 42ت العربية ، التعريب ، العدد الجامعا http://arch.arab-eng.org/uploadfile/uploading/aliraouf.pdf مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 179 ، متطلبات ومعايير إدارة الجودة الشاملة في مؤسسات التعليم العةالي، 1144يحياوي ، نعيمة محمد ، (8 ، االردن . 5/1144-41-41 المؤتمر العربي الدولي لضمان جودة التعليم العاليوقائع 9) david , n. and pilling s. 3000 . changing architecture education : towards a new professionalism , 1 st edition . spon press . london and new york . 10) evans, b. james, a.p, and talbot, r. 1983. introduction: changing design. in: evans, b. james, a. and talbot, r. (editors), changing design, john wiley and sons. 11) gharagedaghi , j. 2006, systems thinking ; managing chaos and complexity, 2nd edition , elsevier,usa. 12) heath, t. 1984. method in architecture, john wiley and sons, chichester. 13) lim,k.c. low, s. attallah, s. cheang, p. and laboone, e.( 3013 ) model for teaching, assessment and learning in engineering education for working adults , ijac volume 5, issue 4, november. ) المكتبة االفتراضية العراقية( 14) jones, c.j. 1981. design methods, john wiley and sons ltd., new york. 15) naab,2008, naab visiting team member training, in: acsa administrators conference – savannah, ga. 16) riba , 2003 , criteria for validation , royal institute of british architects.. 17) rittel,h. 1984. second-generation design methods. in: cross, n. (editor), development in design methodology. john wiley and sons, chichester, new york. 18) sonnenberg , f.k . 2011. managing with a conscience: how to improve performance through integrity, trust, and commitment, 2 nd edition. createspace 19) tokman , l. y. , yamaçlı,r. 2007 . a computer aided model for supporting design education , world academy of science, engineering and technology 92007 , pag 600-604. )المكتبة االفتراضية العراقية ( 20) whyte, j. 3003 . virtual reality and the built environment, is' edition. architectural press, new york , tokyo. 21) www.arch.arab-eng.org. 22) www.naab.org . naab visiting team member training : acsa administrators conference – savannah, ga. 30 ) www.abet.org . criteria for accrediting engineering programs : effective for reviews during the 3013-3013 accreditation cycle . http://www.naab.org/ مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 180 (تقييم منظومة التطوير لقسم هندسة العمارة / الجامعة التكنولوجية1جدول) حلقات التطوير الرئيسة تفاصيل حلقات التطوير درجات تقييم %نتائج ومؤشرات التقييم 2-8 12/ 21 الجوانب االداريـــــة االولى 44بنسبة مئوية % 2-3 32/ 21 الجوانب العلمــــــية الثانية 14بنسبة مئوية % 2-2 22/ 27 الجوانب المنهجية والعمــــلية الثالثة 44بنسبة مئوية % 12/ 45 المجموع الكلي 53بنسبة مئوية % اهم المؤشرات التي اكدت عليها الدراسات السابقة ومعايير بعض منظمات " : 0جدول رقم " لخصوصية المحلية مع مراعاة ا اعتماد برامج التعليم المعماري العالمية بتصرف من قبل الباحثين ت قا حل ر وي ط لت ا الدراسات المؤشرات المستنتجة 1-1 علي (6002) 1-6 ابو سعده (6002) 1-2 فادان (1111) 1-4 الخطيب (6010) 6-1 naab 6-6 abet 6-2 riba المالحظات 21 ية يم ظ تن ال ة ري دا إل ا 2-1-1 ● ● ● ● ● 2-1-6 مراعاة خصوصية العراق ● ● ● 2-1-2 ● ● ● ● 2-1-4 2-1-5 ● ● ● ● ● 26 ية ص ص خ لت ا ية لم لع ا 2-6-1 ● ● ● ● ● ● مراعاة خصوصية العراق والمحيط العربي االسالمي 2-6-6 مراعاة خصوصية العراق ● ● ● ● ● 2-6-2 راقمراعاة خصوصية الع ● ● 2-6-4 ● ● ● ● 2-6-5 مراعاة خصوصية العراق ● ● ● ● 22 ية يق طب لت ا ية ج نه لم ا 2-2-1 ● ● 2-2-6 ● ● ● ● ● ● ● 2-2-2 مراعاة خصوصية العراق ● ● 2-2-4 ● ● ● ● 2-2-5 مراعاة خصوصية العراق ● ● ● ● 2-2-2 ة العراقمراعاة خصوصي ● ● ● ● 2-2-7 مراعاة خصوصية العراق ● ● ● ● مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 181 تفاصيل تقييم منظومة التطوير لقسم هندسة العمارة / الجامعة التكنولوجية(: 2جدول ) درجات تقييم تفاصيل حلقات التطوير حلقات التطوير نتائج ومؤشرات التقييم قرة الف رقم لقة لح م ا اس قرة الف رقم تفاصيل الحلقة جود مو جدا وح وض ةب (5 ) وج م ــــــــــ ــــ ود وح وض ةب (4 ) م ــــــــــ ــــــــــ ــــــــــ جود و ( 3) ة وج ر م ــــــــــ ــــ ةود ا ) سبي ن 2 ) جود مو غير ة ا ) سبي ن 1 ) 3-1 رية الدا ب ا جوان ال 3-1-1 بة وملعنة االهتمام بوضع خطة استراتيجية مكتو • التخطيط لالدارة والتنظيم 3-1-2 دعم معايير االبداع والكفاءة في شغل المناصب االدارية • انتقاء خبرات تؤمن بالتطوير 3-1-3 عمل استمارات تقييم في القسم، اضافة الستمارات تقييم االداء الوزارية • تقييم الخبرات العلمية 3-1-4 الفورية للمتقاعس والشكر والمكافئة الفورية للنشيطتفعيل العقوبة • االدارة بالمباديء 3-1-5 وضع لوائح مكتوبة أو خطة تشغلية لجميع مرافق القسم مكتوبة ومعلنة • وضع لوائح داخلية 12/25 مجموع نقاط تقييم الحلقة االولى %44بنسبة مئوية 3-2 ب جوان ال مية لعل ا 3-2-1 وضــــع رويــــة واهــــدا للبرنــــامج يمي التعل وضـــع ا ـــار اســـتراتيجي واضـــح ومكتـــوا ومعلـــن لكـــل برنـــامج تعليمـــي يفـــتح فـــي • من التخصصالقسم يراعي خصوصية الفكر االسالمي وحاجة المجتمع 3-2-2 المحافظـة علـى وضــع المكتبـة الحــالي والتطلـع نحــو االحسـن مســتقبال مـن خــال • تعزيز قاعدة البيانات )المكتبة( ب والمشاركة بالدوريات العالمية المتخصصة شراء الكت 3-2-3 دعم دور االختصاص الدقيق في تدريس المواد العلمية النظرية والتطبيقية • التخصص الدقيق في التدريس 3-2-4 تعزيز النشر الدوري للمجلة المعمارية العراقية التي تصدر عن القسم • تأسيس نشرة علمية دورية 3-2-5 تنظــيم نــدوات لمناقشــة مشــاكل واقعية معالجـــة المشـــاكل التعليميـــة ومشـــاكل العمـــران مـــن خـــال اقامـــة نـــدوات علميـــة • جديدة والخروج بنتائج تطبيقية 11/25 مجموع نقاط تقييم الحلقة الثانية %11بنسبة مئوية 3-3 ب جوان ال ية عمل وال جية منه ال 3-3-1 وضــــــع اســــــس اختيــــــار لبــــــة عمارة ال اقامـــة نـــدوات ومـــؤتمرات علـــى المســـتوي المحلـــي والـــدولي لوضـــع معـــايير انتقـــاء • الطلبة 3-3-2 التطـــــــــوير المســـــــــتمر للمـــــــــنهج الدراسي وفق خطة استراتيجية دراســـة علميـــة لوضـــع المـــنهج الدراســـي مـــع مفرداتـــم التفصـــيلية وتطبيقـــم ومتابعـــة • الئمــــة المنــــاهج الدراســــية مــــع حاجــــة الخــــريجين للوقــــو علــــى مــــدي فاعليــــة وم المجتمع 3-3-3 نقـــــــــاع حـــــــــر مـــــــــع معمـــــــــاريين ممارسين عــرم ممارســة واقعيــة للعمــارة مــن خــال استنــافة معمــاريين محليــين وعـــالميين • بارزين 3-3-4 ر منهجية التصميم تطوير آلية التعامل مع المشكلة التصميمية المعمارية مع تطوي • اعتماد مناهج تصميم حديثة 3-3-5 الحزم والمتابعة أكثر في تطبيق لوائح الدراسة واالمتحانات واللوائح والقوانين • تفعيل اللوائح والقوانين 3-3-1 توفير اماكن عمل ووسائل تعليمية متطورة أكثر • توفير بيئة مالئمة للتدريسي 3-3-7 دعم أكبر الدوات الرسم االلكترونية ووسائل التعليم المتطورة • توفير بيئة مالئمة للطالب 17/35 مجموع نقاط تقييم الحلقة الثالثة %44بنسبة مئوية 45/45 المجموع الكلي %53بنسبة مئوية مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 182 طريقة التعليم : العرض والتلقين ن طة ق ق ال ط الن ا ة س ر ما لم ا ى ال ية لنــهائالمرحلة الثالثة : ا المرحلة الثانية : األساسية طريقة التعليم : المناقشة والتفكير واالكتشاف االولي طريقة التعليم : االكتشاف والتطوير الغايات: شرح ماهية التصميم شرح عملية التصميم م اساسيات التعبير بالرس ن طة ق ى ول ال ا ق ال ط الن ا الغايات: التفكيةةةةر حةةةةي ليةةةة -عمليةةةةة التصةةةةميم المخطة العةام -خطة التصةميم -المواقع رسوم نفيذية -البعد الرابع الخامسةالسنة الرابعة السنة االثاثة السنة الثانية السنة السنة االولى حية سيادة المقررات النظرية المعر سيادة المقررات التي جمع بين النظرية والتطبيق مشروعات كبيرة مشروعات متوسطة مشروعات صغيرة المرحلة الثالثة والرابعة المرحلة الثانية: قلب العملية التعليمية المرحلة االولى والثانية الشخصية دور الطالب: المشاركة و كوين دور الطالب: االستماع والتعرف دور الطالب: ابتكاري وناضج الغايات: المشروعات المتكاملة الضخمة طوير المهارات حساب التكاليف االبتكار والثقة بالنفس واالستقاللية ع و ر ش م ج ر خ لت ا المقررات التطبيقة عملية االبداع ( لتطوير التعليم المعماري المصمم وفق1112نموذج ابو سعده )(: 1شكل ) المرحلة االولى : التمهيدية المعماري مسؤول عن عملية انتاج المبنى االكاديمية الملكية للعمارة معماري ال يبني ولكنال حرفي يبنونوال العامل العمارة العالميةمدارس الممارسة النظرية للعمارة تنشر وال تبنى مدرسة الفنون الجميلة ضمور سيطرة المعماري على عمليات البناء 8188 8824 8174 المسار النقدي لتاريخ التعليم المعماري:( 0شكل) الباحثون مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 183 أبعاد األداة م ) للبرنامج التعليمي المعماري ( واستراتيجية تحقيقها األهداف 8 ) نوعية الطالب ، شروط قبول الطلبة وتناسبها مع المنهج ( المدخالت 3 تخصصه ، البنى التحتية للتدريسي والطالب ، ادوات التعليم ، المكتبة () التدريسي و البيئة 2 ) يغطي مجاالت التصميم ، مهارات الرسم ، علوم البيئة، يراعي التسلسل والوضوح في اعطاء المعلومة وممارسة المنهج 0 تصميمية مهنية حقيقية (.المهنة ، يراعي البيئة المحلية ، العلوم االنسانية ، النواحي الجمالي ، حل مشكالت ) تقييم اداء الطالب من المشاريع والبحوث واالختبارات، يشجع على االبداع والحوار والمناقشةوالتفكير تنايذ المنهج 2 الناقد،يوجد وعاء زمني وتوصيف لكل مقرر دراسي،مراعاة تخصص التدريسي وتقويمه، يوفر البرنامج انشطة رياضية وفنية فيهية اخرى(واجتماعية وتر ) الخريجون يحققون اهداف البرنامج، توفير تقويم نهائي شامل للطالب من حيث المعرفة والفهم والمهارة والتفكير المخرجات 7 والنقد والتذوق الجمالي ، وجود فرص عمل للخريج ، تحقيق ممارسة المهنة ورضا الجهة المستفيدة من خدمات الخريج ( ) لجان من داخل القسم ، لجان مهنية من خارج القسم ( مج التعليميالبرنا مصادر تقويم 1 ) التحليل، الدراسات السابقة ، المالحظة والمعايشة ، الوثائق ،االستبيانات ،المقابالت ، االختبارات الشاملة ( أدوات التقويم 1 ا : المصدر : ) فادان واخرون ادوات قياس نموذج تقويم برنامج التعليم المعماري واهم عناصره" : 3شكل " ( ملخص من الباحثين8888، الرؤية والرسالة واالهداف 1 ال اكمية والتنظيم 2 البرامج التربوية 3 مصادر التعلم ؛ المكتبات التعلم والتعليم و كنولوجيا المعلومات 5 4 المخرجات 10 الرقابة المسائلة / التقويم 9 التموي 8 العلمي الب ث المراحق التسهيالت الخدمات التربوية 6 7 معايير االعتماد وضب الجودة ،انموذج الخطيب لالعتماد وضبط الجودة في مؤسسات التعليم العالي في الوطن العربي(: 1شكل ) مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 184 conditions for accreditation شروط االعتماد برنامج اجراءات التقييم الذاتي .naab 2الرؤيا الخماسية لل .1 العدالة االجتماعية .4 المعلومات المجتمعية .3 م(ثقافة االستوديو)المرس .5 الموارد .6 الموارد المادية .8 تنمية الموارد البشرية .7 الموارد المالية .10 الموارد المعلوماتية .9 درجة المهنية وتطوير المناهج .12 البنى االدارية .11 (spcمعايير اداء الطالب) .13 ألمريكي ا المعماريم المجلس الوطني العتماد التعليمعايير تقييم البرامج التعليمية المعمارية عند (: 5شكل ) (naab ) لمصدر : ا http://www.naab.org abet mission program educational objectives assess / evaluate constituents / stakeholders evaluation interpretation of evidenece program (student) outcomes feedback for continuous improvement program (student) outcomes program (student) outcomes program (student) outcomes assessment for continuous improvement اس مخرجات التعليم الهندسي عنديوضح الية قي(: 2شكل ) (lim& elt, 2012)المصدر http://www.naab.org/ http://www.naab.org/ مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 185 تحديث البنى التحتية لقسم هندسة العمارة ،وجانب من قاعات التدريس واليات التعليم في القسم . :(7شكل ) المصدر : الباحثون منظومة التطوير باحثونمنظومة تطوير قسم هندسة العمارة / الجامعة التكنولوجية ، إعداد : ال :(8شكل ) ةالمادي البيئة ةفكريالالبيئة بيئة حكرية عامة الثقافة العربية اإلسالمية للمجتمع بيئة حكرية خصصية المناهج والمقررات الدراسية األستاذ جسديا ونفسيا البنى الت تية المباني واألثاث والوسائل التعليمية التطوير العلمي االختصاصي طوير آليات عم ال التطوير اإلداري التنظيمي الطالب جسديا ونفسيا مجلة القادسية للعلوم الهندسية المجلد 7 العدد 4 1024 186 / الجامعة النسبة المئوية لتقييم تطبي الحلقات الثالثة لتطوير قسم هندسة العمارة :(9شكل) التكنولوجية al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 148 assessment of some physico-chemical properties for water in ganga river at varanasi, india suhad a. abed (1) , dr. ali a. jazie (2) (1) m.sc. environmental science (2) department of chemical engineering,alqadissiya university,iraq e mail: jazieengineer@yahoo.com received 9 january 2014 accepted 17 march 2014 abstract during the last few decades, anthropogenic activities have dramatically attired the quality of surface waters including those of rivers. the rising level of pollutants and changes in mid stream water quality of ganga river have received serious attention of scientist and policy makers in india. the present investigation was attempted to study water quality of river ganga and to record the qualitative change in water if any during the three consecutive months of sampling in 2013. a systematic study has been carried out to assess the water quality of river ganga in varanasi city. 36 water samples from four sampling stations i.e. by pass bridge upstream, assi ghat, dashswamedh ghat, and raj ghat bridge downstream, were collected and analyzed for physico-chemical parameters (temp, ph, hardness, total dissolved solids, dissolved oxygen, b.o.d., and free co2) .the analytical data of various physicochemical parameters indicates that some parameters like ph, hardness and total dissolved solids are found to be in excess than the prescribed limit in some water samples of the study areas as compared to world health organization standards (whos). key words: water pollution, ganga river water, physicochemical analysis الهندية بنارس مدينة في الكنج نهر للماء في الكيمياوية و الفيزياوية الخواص بعض تقييم الخالصة ى نوعية المياه السطحية خالل العقود القليلة االخيرة ازداد تاثير اال نشطة والفعاليات االنسانية والصناعية عل ومنها مياه االنهار. ان ارتفاع مستوى الملوثات والتغيرات الكبيرة في نوعية المياه في مجرى نهر الكنج جعله محط اهتمام العلماء والساسة في الهند. الدراسة الحالية هي محاولة لتقييم نوعية المياه في نهر الكنج من خالل قياس (. تم اجراء دراسة 3102ه التي حدثت خالل ثالثة اشهر )كانون الثاني, شباط, اذار( لسنة )التغيرات النوعية للميا ( نموذج من اربع محطات مختلفة على طول مجرى 23منتظمة على مياه نهر الكنج في مدينة بنارس الهندية واخذ ) mailto:jazieengineer@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 149 عية المياه في نهر الكنج ان بعض النهر في المدينة المذكورة اعاله. تبين من خالل دراسة العوامل المؤثرة على نو العوامل مثل الحامضية, العسرة وكمية المواد الصلبة الذائبة الكلية كانت اكثر من الحدود المسموح بها في مواصفات . منظمة الصحة العالمية 1. introduction the ganga is a major river in india, flowing east through northern india into bangladesh. its basin covers 861,404 km 2 , which is approximately 26 percent of the total land area of india. there are numerous settlements (cities, towns and villages) located in the basin, comprising 45 percent of the country’s population, i.e., approximately half a billion people. this figure is expected to double by 2030 (bennett and biroll, 2010)[1]. defined as the ‘river of india’ by nehru, ganga has important economic, social, cultural and religious values. it accounts for about 31.6 percent of india’s annual utilizable water resources, providing water for agriculture, aquaculture, hydropower generation, industry, and water supply for household consumption (bureau of applied economics & statistics, 2005)[2]. the ganga is a major input to agricultural production, as the soil in the river basin is very fertile, and the river provides a perennial source of irrigation to a large area, enabling cultivation of several crops. even though there are some industries which pollute the ganga, most notably the leather industry, the main source of pollution is human waste. untreated raw sewage discharged in the ganga is estimated to be as much as one million m 3 per day (murty et al., 2000)[3]. the ganga accumulates large amounts of human pollutants (e.g., schistosoma mansoni and faecal coliforms) as it flows through highly populous areas. these pollutants carry significant health risks for humans, as well as environmental risks for the sustainability of the ecosystem services provided by the ganga. proposals have been made to reduce the amount of untreated raw sewage deposited in the ganga. the most noteworthy of these is the ganga action plan (gap). initiated in 1984 by the indian government, and supported by the netherlands, uk and voluntary organizations, the aim of the gap is to build a number of wastewater treatment facilities for the immediate reduction of sewage in the river. even though over us$33 million has already been spent under the gap, so far no great progress has been achieved (birol and das, 2010)[4]. a number of investigations have been conducted to study the physicchemical properties of water in different rivers [5-12]. looking into the relevance of data on changing water quality of ganga river, the present work was an attempt to assess the impact of monthly changes on the physio-chemical properties of water of river ganga at four selected sampling sites at varanasi. the sites include bypass bridge upstream, assi ghat, dashwamedh ghat, raj ghat bridge downstream. the water of river ganga at aforesaid sites was analyzed for temperature, ph, hardness, dissolved oxygen, biochemical oxygen demand, total dissolved solid, and free co2. 2. materials and methods 2.1.study area and sites varanasi, also benares, banaras or kashi, is a city on the banks of the ganges in uttar pradesh, 320 kilometers southeast of the state capital, lucknow. it is holiest of the seven sacred cities in hinduism and jainism. the city of varanasi encompasses a total area of 1550.3 sq. km. it holds a population of 25.0811 lakhs with 10.5797 lakhs of urban and 14.5014 lakhs of rural population (as per 1991 census). figure 1 shows the drainage area of the ganga river covering 11 states in india. varanasi has a humid al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 150 subtropical climate with much variation in temperatures. varanasi has at least 84 ghats (steps in the ghats lead to the banks of river ganga). as per scientists associated with the ganga action plan, the river is changing course due to massive pollution and lack of proper cleaning of the banks of the river [4]. the following study was conducted at four selected sites of river ganga at varanasi during the period of january 2013 to march 2013. the selected sites were bypass bridge upstream, assi ghat, dashwamedh ghat, raj ghat bridge downstream. 2.2.sampling a total of 36 water samples were collected from four different spots during a period of 3 months (january 2013 to march 2013). water samples were collected at monthly interval for a period of 3 months i.e.january-march between 1.00 pm to 8.00 pm from four sampling sites i.e. by pass bridge upstream, assi ghat, dashswamedh ghat, and raj ghat bridge downstream. the samples were taken in plastic jerry canes and brought to the laboratory with necessary precautions. all samples were labeled properly. the temperature was recorded at the sites with the help of digital thermometer. grab sampling was generally applied during the sampling. figures 2-3 show the sampling process at the four sites of ganga river. 2.3.analysis the water samples were brought to the laboratory and analyzed by standard methods [13-16].the samples were analyzed for the following physicochemical parameters: water temperature (ºc), ph, hardness (mg/l), total dissolved solids (mg/l), free co2(mg/l), dissolved oxygen (mg/l), and b.o.d. (mg/l). it is an established fact that the more harmful a given pollutant is, the smaller is its standard permissible value recommended for drinking water. standard method for the examination of water and waste water was used (apha, 1998) [13] for analysis. the temperature of water was recorded directly in sampling sites using digital thermometer. the digital thermometer had a thermocouple was immersed in the water for the desired level. ph meter hach ec10 was used and this method gave an accurate and quick measure of the ph. the essential feature of a ph meter is that it contains hydrogen sensitive electrode called indicator electrode and a colomel reference electrode. most ph meters possess a temperature compensation system to avoid the difference arising due to the different temperatures. hardness was calculated using etda titration method. total dissolved solids were calculated by drying at 180 o c. dissolved oxygen and biological oxygen demand were calculated using the standard method. in the experimental part we have used numerous chemicals and required for determination of water parameters of ganga river. some chemicals have been from chemical purifier “pro analysis” (p.a.), whereas some suprapur. preparation of solutions is done with bidestillated water. 3. results table 1 and figure 4 shows the monthly variations in the temperature ( o c) of river ganga at varanasi city. temperature is the important factor which influences the chemical, biochemical and biological characteristic of the aquatic system. temperature also alters the saturation values of solids and gases in water. the present investigation reveals that the temperature varied from a minimum 15.4 o c in jan (by pass bridge upstream) to maximum 23.6 (raj ghat downstream) in march. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 151 table 2 and figure 5 shows the monthly variations in the ph of river ganga at varanasi city. because most of the chemical and biochemical reaction are influenced by the ph it is of great practical importance. the adverse affect of most of the acids appear below 5 and of alkalis above the ph 9.5.the ph values were higher in january with the highest value 8.7 in jan at dashswamedh ghat and lowest value 8.4 in faberuary at raj ghat downstream. table 3 and figure 6 shows the monthly variations in the hardness of river ganga at varanasi city. the hardness values were higher in january with the highest value 182 mg. l -1 in jan at bypass bridge upstream and lowest value 162 mg. l -1 in march at raj ghat downstream. table 4 and figure 7 shows the monthly variations in the total dissolved solid of river ganga at varanasi city. total solids may affect water quality. water with high total solids generally is of inferior potability. total dissolved solids were observed maximum 250 mg. l -1 in february at raj ghat downstream and minimum 87.33 mg. l -1 in february at bypass bridge upstream. table 5 and figure 8 shows the monthly variations in the dissolved oxygen of river ganga at varanasi city. temperature plays an important role in determining do in an aquatic body. dissolved oxygen data are valuable in determining the water quality criteria of an aquatic system. in the system where rate of respiration and organic decomposition are high, the do values remain lower than those of system where the rate of photosynthesis is high. a high pollution load may also decrease the do values to considerable level .the do values range from a minimum of 4.9 mg. l -1 (march) at dashswamedh ghat to maximum of 8.8 mg. l -1 (february) at assi ghat. lower do values during march may be attributed to the high temperature and its consumption due to high growth and activities of microorganism. the higher concentrations of dissolved oxygen during january and february were probably due to low water temperature, no turbidity and increased photosynthetic activity of the green algae found on the submerged stones and pebbles. table 6 and figure 9 shows the monthly variations in the biochemical oxygen demand of river ganga at varanasi city. bod has been used as a measure of the amount of organic materialism an aquatic solution which supports the growth of microorganism (goel, 2006) [17]. bod determines the strength or polluting power of sewage, effluents and other polluted waters and provides data on the pollution load in natural waters. higher values of bod indicate a higher consumption of oxygen and a higher pollution load. the bod values range from 12.3 mg. l -1 (jan) at bypass bridge upstream to a maximum of 43.33 mg. l -1 (february) at raj ghat downstream. the bod values in the present study are less than the values reported by tripathi et al. (1991)[18]. free carbon dioxide in the ganga water was absent throughout the three months of the present study. 4. conclusion the water is getting polluted day by day by the increasing concentrations of different pollutants. the river ganga is a sacred river but becoming polluted at this ancient pilgrimage, possibly due to rising anthropogenic influence. there are several factors which are responsible for degraded condition of river water quality. the far most seems to be the restriction of river’s natural flow because of the tehri dam in uttarkhand, the reduced stream flow declines the river’s self cleansing properties. this is probably the biggest issue and cause of rising river siltation and degrading water quality. discharge of sizable amount of untreated domestic and industrial waste and run off from agriculture farms provide exhaustive source of pollutants addition to ganges basin. there are some other reasons unchecked like disposal of dead bodies and animal carcasses in the river, the washing of cloths and bathing of animals on the river banks, besides defecation and other activities. in the present study, it was found that the properties like hardness, tds and bod were increased in all the sites of the study, while do and ph al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 152 were decreased. ganga river water also was changed from fresh bluish to dirty turbid and due to the upper resons, the penetration of light has reduced, thereby reducing the primary productivity of the river by phytoplankton and hence do which is used by aerobic bacteria during the decomposition of organic materials and increase the bod. because of these ill effects of increasing pollution the aquatic flora and fauna of river ganga has disturbed due to which the aquatic food chain has also been disturbed. the result of these effects can be seen on gange’s dolphin which has now become endangered. damming across the river and huge accumulation of sand and salt along its banks and long water course have reduced the natural flow and carrying capacity of river because of which siltation has increased and the river has construct and meandered that is why the dissolution capacity has reduced significantly. in addition, the concentration of harmful chemicals which are toxic to aquatic life has increased and therefore variety of fishes, zooplankton, and phytoplankton has also reduced and consequently the food chain has been disturbed. such a high pollution has reduced the fishing, tourisms at the ghat of varanasi as well as continuously losing of cultural value also for which the place is famous in the world. in order to keep the cultural value as well as natural quality and to maintain the flora and fauna of river ganga, the pollution must be reduced by creating awareness among the local people about it is importance and the status of present and future ill effects along with the changes in policy decisions of state and central government for maximizing the effects towards conservation of this major river system. references [1] bennett, j.w., birol, e. (eds.), 2010. choice experiments in developing countries: implementation, challenges and policy implications. edward-elgar publishing, cheltenham, uk. [2] bureau of applied economics & statistics, govt. of west bengal, 2005. http://www. indiastat.com/india/state.asp?stid=26&secid=131&ptid=24&level=4. [3] murty, m.n., james, a.j., misra, s., 2000. economics of water pollution: the indian experience. oxford university press, new delhi. [4] birol e., das s., 2010, estimating the value of improved wastewater treatment: the case of river ganga, india, journal of environmental management 91, 2163-2171. [5] scarpa, r., drucker, a., anderson, s., ferraes-ehuan, n., gomez, v., risopatron, c.r., rubio-leonel, o., 2003. valuing animal genetic resources in peasant economies: the case of the box keken creole pig in yucatan. ecological economics 45 (3), 427-443. [6] othman, j., bennett, j., blamey, r., 2004. environmental values and resource management options: a choice modelling experience in malaysia. environment and development economics 9, 803-824. [7] bienabe, e., hearne, r.r., 2006. public preferences for biodiversity conservation and scenic beauty within a framework of environmental services payments. forest policy and economic 9, 335-348. http://www/ al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 153 [8] hope, r.a., 2006. evaluation water policy scenarios against the priorities of the rural poor. world development 34 (1), 167-179. [9] bush, g., colombo, s., hanley, n., 2009. should all choices count? using the cut-offs approach to edit responses in a choice experiment. environmental and resource economics 44 (3), 397-414. [10] gupta, s.c, rathore g.s. and mathur, g.c.d. (2001) hydro –chemistry of udaipur lakes indian journal of environment and health, 43(1), pp.38-44. [11] throat ,s.r. and masarrat sultana ,(2000) pollution status of salim ali lake ,aurangabad (m.s.) journal of pollution research 19(2), pp. 307-309. [12] yogesh shastri and pendre, d.c (2001) hydrobiological study of dahikhuna reservoir journal of environmental biology 22 (1), pp.67-70. [13] american public health association. apha. (1998). standard methods for the examination of water and wastewater, 20. [14] manual on water and waste water analysis. (1988). neeri publications. [15] mathur r.p. water and waste water testing. (1982). nem chand and brothers, publishers, roorkee, 1-54. [16] mishra p. and patel r.k. (2005). some aspects of the quality of water in and around rourkela. thesis. [17] goel, p. k. (2006).water pollution: causes, effects and control. new age international. [18] tripathi b. d., sikandar m., shukla s. c. (1991). physico-chemical characterization of city sewage discharged into river ganga at varanasi, india. environment international 17: 469-478. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 154 site and sub site sampling date site sub site 13 th january 7 th february 3 rd march by pass bridge up stream city side bank 15.2 19 23.5 mid stream 15.3 18.8 23.1 off side bank 15.7 20 24 average 15.4 19.26667 23.53333 assi ghat city side bank 15.7 21.2 23.5 mid stream 15.5 19 23 off side bank 16 21.5 23.7 average 15.73333 20.56667 23.4 dashswamedh ghat city side bank 15.1 19.1 23.3 mid stream 15.5 18.7 22.9 off side bank 15.9 20 23 average 15.5 19.26667 23.06667 raj ghat bridge down stream city side bank 15.3 18.8 23.5 mid stream 15.9 19.2 23.3 off side bank 16 20 24 average 15.73333 19.33333 23.6 table 1: monthly variation in water temperature ( o c) of river ganga at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 155 site and sub site sampling date site sub site 13 th january 7 th february 3 rd march by pass bridge up stream city side bank 8.26 8.2 8 mid stream 8.68 8.65 8.65 off side bank 8.53 8.33 8.5 average 8.49 8.393333 8.383333 assi ghat city side bank 8.35 8.3 8.41 mid stream 8.76 8.73 8.74 off side bank 8.64 8.6 8.61 average 8.583333 8.543333 8.586667 dashswamedh ghat city side bank 8.65 8.48 8.53 mid stream 8.63 8.6 8.67 off side bank 8.72 8.72 8.64 average 8.666667 8.6 8.613333 raj ghat bridge down stream city side bank 8.68 8.68 8.58 mid stream 8.58 8.6 8.55 off side bank 8.62 8.6 8.5 average 8.626667 8.626667 8.543333 table 2: monthly variations in water ph of river ganga at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 156 site and sub site sampling date site sub site 13 th january 7 th february 3 rd march by pass bridge up stream city side bank 190 188 172 mid stream 178 180 174 off side bank 178 178 168 average 182 182 171.3333 assi ghat city side bank 168 166 160 mid stream 162 168 162 off side bank 176 174 165 average 168.6667 169.3333 162.3333 dashswamedh ghat city side bank 168 170 165 mid stream 166 164 166 off side bank 170 168 167 average 168 167.3333 166 raj ghat bridge down stream city side bank 164 160 156 mid stream 168 168 160 off side bank 172 170 170 average 168 166 162 table 3: monthly variations in the hardness (mg. l -1 ) of water of river ganga at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 157 site and sub site sampling date site sub site 13 th january 7 th february 3 rd march by pass bridge up stream city side bank 90 92 120 mid stream 75 100 95 off side bank 124 70 190 average 96.33333 87.33333 135 assi ghat city side bank 100 126 130 mid stream 180 200 210 off side bank 205 220 212 average 161.6667 182 184 dashswamedh ghat city side bank 60 90 140 mid stream 72 116 150 off side bank 210 170 90 average 114 125.3333 126.6667 raj ghat bridge down stream city side bank 75 90 120 mid stream 230 260 136 off side bank 320 400 260 average 208.3333 250 172 table 4: monthly variations in the total dissolved solid (mg. l -1 ) in ganga river at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 158 site and sub site sampling date site sub site 13 th january 7 th february 3 rd march by pass bridge up stream city side bank 8 8.5 5.1 mid stream 7.8 8.7 5 off side bank 7.4 9.1 5.1 average 7.733333 8.766667 5.066667 assi ghat city side bank 6.8 8.8 4.6 mid stream 7.6 8.6 5.4 off side bank 8.4 9 5.6 average 7.6 8.8 5.2 dashswamedh ghat city side bank 5.3 7.1 4.5 mid stream 5.9 7.9 5.1 off side bank 6 8.9 5.1 average 5.733333 7.966667 4.9 raj ghat bridge down stream city side bank 5 8 5.2 mid stream 4.6 7.8 5.2 off side bank 5.4 7.4 5.6 average 5 7.733333 5.333333 table 5: monthly variations in the dissolved oxygen (mg. l -1 ) in ganga river at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 159 site and sub site sampling date site sub site 13 th january 7 th february 3 rd march by pass bridge up stream city side bank 10 15 20 mid stream 15 18 17 off side bank 12 15 33 average 12.33333 16 23.33333 assi ghat city side bank 20 33 60 mid stream 15 20 35 off side bank 28 25 28 average 21 26 41 dashswamedh ghat city side bank 15 35 20 mid stream 17 38 35 off side bank 21 39 30 average 17.66667 37.33333 28.33333 raj ghat bridge down stream city side bank 20 40 46 mid stream 27 40 30 off side bank 30 50 44 average 25.66667 43.33333 40 table 6: monthly variations in the biochemical oxygen demand (mg. l -1 ) in ganga river at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 160 figure (1): drainage area of the ganga river covering 11 states in india al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 161 figure (2): water temperature recording in mid stream of ganga river figure (3): sampling in mid stream of ganga river al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 162 0 5 10 15 20 25 bpu ass das rgd r iv e r te m p e ra tu re , o c sampling site 13 th jan. 7th fab. 3rd march 8.2 8.25 8.3 8.35 8.4 8.45 8.5 8.55 8.6 8.65 8.7 bpu ass das rgd p h sampling site 13 th jan. 7th fab. 3rd march figure (4): monthly variation in water temperature ( o c) of river ganga at varanasi figure (5): monthly variations in water ph of river ganga at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 163 150 155 160 165 170 175 180 185 bpu ass das rgd h a r d n e ss , m g .l -1 sampling site 13 th jan. 7th fab. 3rd march 0 50 100 150 200 250 300 bpu ass das rgd t o ta l d is so lv e d s o li d , m g .l -1 sampling site 13 th jan. 7th fab. 3rd march figure (7): monthly variations in the total dissolved solid (mg. l -1 ) in ganga river at varanasi figure (6): monthly variations in the hardness (mg. l -1 ) of water of river ganga at varanasi al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 164 0 1 2 3 4 5 6 7 8 9 10 bpu ass das rgd d is so lv e d o x y g e n , m g .l -1 sampling site 13 th jan. 7th fab. 3rd march 0 5 10 15 20 25 30 35 40 45 50 bpu ass das rgd b io lo g ic a l o x y g e n d e m a n d , m g .l -1 sampling site 13 th jan. 7th fab. 3rd march figure (8): monthly variations in the dissolved oxygen (mg. l -1 ) in ganga river at varanasi figure (9): monthly variations in the biochemical oxygen demand (mg. l -1 ) in ganga river at varanasi al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 94 a computation fluid dynamic investigation into the use of baffles in potable water treatment plant process tanks in iraq ali h. ghawi phd college of engineering al-qadisiya university abstract the reaction that takes place in a process tank is in a large way dependent on the internal hydraulics of the tank, irrespective of the type of tank. in some tanks mixing is desirable in others plug flow is desirable. in most tanks it is very hard to achieve either of the two. this is partially due to the fact that the area through which the fluid enters the tank is small in relation to the tank cross sectional, complex geometries and changes of fluid direction. baffles can in some cases offer cost effective and simple solutions. this paper demonstrates how computation fluid dynamic (cfd) can be used to improve process tanks performance in iraq water treatment plant by the introduction of baffles. keyword: baffle, sedimentation tanks, reservoirs, chlorine contact tanks, flocculates, ���ِب ا�� ِ�� �ا�ِ ا�����ل �� ���ِ���� � د�� ا�'��& ��%�ت ����#ِ ا���ِءأ��اِض �� ��ا �� ا��)اق�*()ب 1*� ه�دي /�وي. د �2 آ* ا�3 ����� ا���د ا�567 ���ة ��� �� ��� ا���ب َ��� َ��ٍ� آ ���� ، 45�ف ا�02ّ� �/ �.��اض� �ا��ا-� �ا�,��رو��(�ا��)��' ا�&ي َ$ْ��ُث � أ��اض . � 5َْ ? ا<��اض =(�ن ����� ا���$�ن ا���aوج �:��5 و ا� ? ا<-� =(�ن ����� ا���$�ن ا���� ;ِِ �:��5ُ. ��ِع ا���ِض � f إن �pq2 د-�ل ا���lm إ�� ا���ض ij��ة 5". � أآg� ا<��اض / ا�4 �e fًا ان $�4' ا�2bcن r5 �p�pه&ً� ا�� � r2�� �� ا���ض�r �,� ا��pرة ��� =�p' آ�)� ���� ا���ء ا�u��4 ا���4ات . ا��(' ا�� �pة ����ض و ا��i�� � ا=��� ا���$�ن ,إ�� ���ل y,�� و �q�r5 � ����� ا�� ���� و ��w��x أ��اض ا�� ���ِ� � �= z�&و آ ���� ت ا���q� �] ه&�. ����ب � bأ �yا��را ��rب ا���lm آ�)�� ان د�2$ ��)� )cfd (اض�� ��� ا���ب � $�(/ أن ُ=�َr �rّ��� 'َ�ُ/ أداُء ا< ���� ��qت � � �x�rا�� .�x�y�5ام ا���4ات ا� �اق و ���5� ا���4ل ��� ����� �p5�q ����اj)�ت ا� ����� ���2�� ا���ء ا�u��4 ����ب al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 95 nomenclature ρr reference density (clean water). u0 influent velocity hin depth of influent stream c solid concentration ss specific gravity of the solid particles k turbulence kinetic energy ε dissipation of turbulence energy φ denotes general dependent variables expressed as a physical quantity per unit mass. u, v stand for x, y velocity components ρ density гφ diffusion coefficient sφ source term corresponding to φ vs settling velocity vo stokes velocity (settling velocity of single particle in clear water) k an empirical coefficient for rapidly settling flocks cmin concentration of non-settling flocks k1 a settling exponent for the poorly settling particles p production of turbulent energy by the mean velocity gradients c1, c2 , cµ k-ε model constants σk , σε: turbulent prandtl numbers for k and ε, q constant flowrate, t theoretical mean residence time ci tracer concentration e(t) normalized residence – time distribution function r normalised concentration of the tracer f densimetric froude number cfd computational fluid dynamic rtd residence time distribution ss suspended solid introduction successful design and reliable operation of new water treatment facilities and the constant upgrading of existing plants has always been, and continues to be a major concern for all world water professionals. the main objective is to ensure the adequate treatment process and to guarantee its maximum efficiency. in flow dynamics a baffle is a device used to alter the flow pattern in a tank. baffle also means to be puzzled or perplexed the state of mind designers are in when the process tank does not perform the way it was supposed to. fortunately modifications can be made to the tank after construction to improve its performance. one of the most cost effective ways to achieve this is by means of a baffle. unfortunately the selection of a baffle to suite a specific process tank is not a trivial exercise, especially with only the conventional design methods at hand. the degrees of freedom in terms of size, vertical and horizontal position and type of baffle make it almost impossible to make the right choice the first time. the effect of a baffles can normally only be seen after the baffle has been installed. scale models can give some guidance, but are often plagued by scale effects which mean that what happens in the lab does not happen in the plant. computation fluid dynamic (cfd) modelling is being increasingly used in a wide range of both water and wastewater treatment applications. the cfd modelling work reported here was carried out using fluent software. very few guidelines exist for the optimal use of baffles in process tanks in wtps. this shortcoming often results in baffles performing less effective for the following reasons: al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 96 conventional wisdom is often proved wrong due to a lack of understanding of the complex flow patterns in most process tanks. empirical data is not available to give quantitative guidelines. experimental trial-and-error type investigations are time consuming and costly. what can be done to improve the situation? before this question is addressed, a short digression on the use of baffles. the aim of this project was originally stated as to improve the operation and performance of iraqi water treatment plant (wtp) which have been identified as operating poorly, by predicting the existing flow, flocculent and chlorine concentration distribution of the (sedimentation, reservoirs, chlorine contact, and flocculators tanks) by means of cfd techniques. details about the model characteristics , initial and boundary conditions are presented in kris and ghawi 2007, ghawi and kris 2007 a, and ghawi and kris 2007b. for this study the flow field is considered to be isothermal, incompressible and without phase change. the cfd package fluent 6.3.26 was used for the case study of the effect of adding a control baffle on the efficiency of tanks and then on efficiency of wtp in iraq. 2. material and methods 1 how baffles are used the purpose of introducing baffles varies from tank to tank, but can include the following: in some cases it can be used to force the flow in such a way that the fluid moves more or less at the same velocity everywhere in the tank. examples of such tanks would include tanks where contact between water and a disinfectant is required such as chlorine. some process tanks require deliberate velocity gradients to enable collisions between suspended particles as in the case of a hydraulic flocculator. baffles can be used to cause the flow to zig-zag or to spiral (figure 1a). in other cases baffles are introduced to generate turbulence and improve the mixing of a chemical with the bulk fluid such as a static mixer (figure 1b). most of the above cases use solid baffles to direct the flow, but baffles can also be used to damp the inlet jets, by dispersing it over a larger area. perforated baffles can be used for this purpose as in the case of a sedimentation tank (figure 1c). two types of baffles can therefore be distinguished: solid baffles, used as obstructions perpendicular to the flow to change the direction of the flow. perforated baffles, used to break up the main jet into a more uniform current over a larger area without the deliberate intention to change the direction. in most cases baffles are designed as part of the process tank, but in some cases the reality check requires the introduction of additional baffles or modified baffles after the construction of the tank. baffles are then used to deliberately separate the inlet and outlet to prevent short circuiting or improve the level of plug flow or mixing. baffles can play an important part in the improvement of process tanks, and design tools to determine baffle placement can assist designers. not only can it potentially save on the initial capital cost of a process tank, but it can also reduce the operating and maintenance costs. cfd provides a generic framework by which baffles can be designed. in this study we use different kind of baffles in different position in sedimentation tanks, reservoirs, chlorine contact tanks, and flocculators tanks in wtps in iraq to improve the operation and performance of wtps. cfd model and residence time distribution (rtd) model are used to analysis the flow and concentration of suspended solid, flocculent and chlorine in wtps. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 97 2 the cfd model the flow patterns for density-stratified fluids in the tanks are usually quite different from those with uniform density under the same external and boundary conditions. the relative importance of inertial and gravity forces in the tanks can be characterized in terms of the initial momentum and buoyancy flux defined by the inlet densimetric froude number, f. 2/1 2 0 )( /       − = r rin gh uf ρ ρρ (1) in which ρr = the reference density (clean water). the value of ρ is the local density of mixture; u0 = influent velocity; and hin= depth of influent stream. the local fluid density is related to the local values of sediment concentration given by )1( 1− −+= sr scρρ where c = solid concentration and ss = the specific gravity of the solid particles. a numerical model consists of a set of conservation equations for continuity and momentum, turbulence kinetic energy k, dissipation of turbulence energy ε and solid concentration. they can be expressed as in a governing equation continuity equation φ + ∂ ∂ φ γ ∂ ∂ = ∂ ∂ + ∂ ∂ s j x j xj u j xt )()( )( φ φρ ρφ (2) suspended solid (ss) concentration equation )()( )( i c s v y i c zy v yx i c zx v xy i c v x i c u t i c + ∂ ∂ ∂ ∂ + ∂ ∂ ∂ ∂ = ∂ ∂ + ∂ ∂ + ∂ ∂ (3) where φ denotes general dependent variables expressed as a physical quantity per unit mass. further, u, v, ρ, гφ and sφ stand for x, y velocity components, density, diffusion coefficient and source term corresponding to φ, respectively. eq (2) is a convection and diffusion equation for the suspended solid particles where vs is the settling velocity. the main feature of the density–induced flow field in settling tank is known to be strongly affected by solid distribution and removal rate. the settling velocity of a particle contained in a disperse suspension, as specially found in settling tank, is also dependent on both its individual characteristics (size, density, shape, etc.) and interactions with other particles. in low concentration, the effect of particle interaction is not significant and thus each particle settles as a separate entity while in high concentration, inter-particle force hinders the settling process of the particle, which settles as a unit, with decreasing mass velocity as the concentration increases. therefore modeling the settling properties of ss is one of the significant processes in the development of solid transport models of settling tank. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 98 a number of empirical formulas have been proposed to describe the relationship between solid concentration and solid settling velocity. a monodisperse settling model in which the average settling velocity vs of the settleable fraction of ss is given by the sum of two exponential terms: [ ])()( 0 minmin cckcck s ieevv −−−− −= (4) where vo = stokes velocity (settling velocity of single particle in clear water) k = an empirical coefficient for rapidly settling flocks cmin = the concentration of non-settling flocks k1 = a settling exponent for the poorly settling particles the first term in eq. (4) reflects the settling velocity of the large particles, whereas the second term is a velocity correction factor to account for the smaller, slowly settling particles. for low concentration, eq. (4) is more sensitive to k1 and it gives increasing values of vs as the concentration increases, whereas for high concentration it reduces to vesilind's equation. the regions of low and high solid concentrations are separated by the point where vs reaches a maximum value. the eddy viscosity, νt is calculated from the k-ε turbulence model which relates νt to the turbulence kinetic energy of k and the turbulence dissipation rate ε. the formula is: εµ 2 k ctv = (5) the distribution of k and ε is calculated from the following semi-empirical transport equations. ε ∂ ∂ σ∂ ∂ ∂ ∂ σ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ −++=++                 p y k yx k xy k v x k u t k k tv k tv (6) k cp k c yyxxy v x u t t v t v 2 21 εε ∂ ∂ε ∂ ∂ ∂ ∂ε ∂ ∂ ∂ ∂ε ∂ ∂ε ∂ ∂ε εε σσ −++=++                 (7) in which p is the production of turbulent energy by the mean velocity gradients as the k-ε model constants, c1, c2 and cµ as well as turbulent prandtl numbers for k and ε, σk and σε are selected as the conventional standard values of 1.42, 1.68, 0.09, 0.9 and 0.9, respectively. boundary conditions for u, v, k, ε and ci are minutely presented in a previous work ( kris and ghawi 2007) and are briefly mentioned for completeness. a uniform parallel inlet flow is assumed with specified values of k and )/(4/3 2/3 m lkc µ ε = (8) the inlet ss loading is assumed to be in a well mixed state with dimensionless concentration unit. the outlet boundary values are computed from near outlet grid points by satisfying the overall mass continuity. near wall velocities parallel to the wall are calculated using the local logarithm law. near wall k and ε can be calculated from the assumption of local equilibrium condition. the tank bottom is treated as a perfect absorbing boundary where particles may not be resuspended by the fluid flow. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 99 3 residences-time distribution (rtd) model residence time distribution (rtd) analysis provides means of assessing the homogeneity of water age in a tank. a plot of the fraction of water leaving the tank outlet as a function of time can be used to assess the extent of short-circuiting and the existence of low flow zones in the tank. traditionally, this has been measured by conducting a physical tracer study on the tank. the following background equations and definitions are used in the proposed model. considering a volume v and constant flowrate q, the theoretical mean residence time t is given by q v t = (9) the normalized residence – time distribution function e(t) after an instantaneous (pluse) tracer input is defined as : ∑∫ = ∞ ∆ ≈= n i ii ii tc c cdt c e 1 0 (10) where t denotes time, and ci is the tracer concentration measured at the outlet at time ti .an alternative to the pulse tracer study is the step tracer study. in this case, at t = 0 the tracer is “switched on” at the tank inlet and remains “on” for the remainder of the study. the normalised concentration of the tracer measured at the tank outlet under steady-state operation is r (eq. 11). the relationship between e and r is given by eq. 12. ∑∫ = ∞ ∆ ≈= n i ii ii tc c cdt c r 1 0 (11) ∫ ∞ = 0 edtr (12) while either a pulse or step physical tracer study can be used to determine the rtd of an operational tank, a physical tracer study can only be undertaken for operating conditions which are feasible in the physical tank. other scenarios, such as the performance of the tank for operating conditions outside normal operating conditions, or the impact on the flow of physical tank modifications, cannot be assessed in advance using this method. an equation was solved for “residence time”, this being the mean age in the water in each cell since its entry to the tank. contour plots of this variable give a good indication of how well mixed the water is, and whether there are any stagnant zones. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 100 result and discussion 3.1 baffle dynamics 3.1.1 the importance of inlets and outlets one of the reasons why process tanks do not always behave according to designers’ intuition, is because of the mechanisms at play near the inlets and outlets of process tanks. the inlet and outlet of a tank determines to a large extent the internal flow patterns in the tank. it is not often realized, but mechanisms applicable to inlets and outlets differ fundamentally. inlets inject momentum (kinetic energy) into a process tank. this changes the mass inside the tank as well as the velocity of the surrounding fluid. the momentum is a vector and can therefore vary in terms of intensity as well as direction. the way in which the fluid enters a process tank often determines to a large extent the way in which the complete tank behaves. in some cases where more than one phase is present, as in the case of a sedimentation tank, not only kinetic energy is added to inlet, but also potential energy. this is caused by the density differences between the fluid and the suspended particles. an outlet on the other hand removes mass from the tank, but does not contribute to the removal of momentum in a similar way as at the inlet. also the effect of an outlet is only local and does not normally affect internal hydraulics in the same way as the inlet. an outlet withdraws the fluid closest to it at the time. the fact that the inlet injects momentum and the outlet not, does not make an outlet less important. it is crucial to carefully select the position of the inlet in relation to the outlet to ensure that the process tank performs effectively. in many cases the process tank outlet is dictated by the external piping configuration and not the internal processes. this can have adverse effects on the internal flow patterns as well as the process efficiency. this following section demonstrates how cfd can be used to improve process tank efficiency by introducing baffles. a number of process tanks that are typically used in the water industry are used as case studies to demonstrate this. the examples include: sedimentation tanks reservoirs chlorine contact tanks, and flocculators the focus is on the insight gained by applying cfd and how it can be used to improve process tank efficiency for these tanks in some wtps in iraq. 3.2 chlorine contact tanks and clean water reservoirs the purpose of a chlorine contact tank is usually two fold, the one is to act as a operational balancing storage device and the other is to achieve proper disinfection by forcing contact between the disinfectant and the water. clean water reservoirs were traditionally considered to have an emergency and balancing storage function only, but they also act as large reactors in the distribution system. a number of studies demonstrated how poor internal hydraulics can influence water quality in a distribution reservoir. it was also demonstrated how the inlet and outlet configuration influences the internal hydraulics which in turn influences the water quality in the reservoir. the design objective is therefore to achieve a uniform as possible flow pattern to ensure that the fluid moves continuously and that sufficient contact between the water and the disinfectant is achieved. this can only be achieved if the internal hydraulics of the tank is properly understood. two problems are usually al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 101 associated with these types of tanks viz. short-circuiting of the inlet and outlet and the presence of stagnant areas. most effective ways these tanks can be improved is by: repositioning the inlet repositioning the outlet introducing internal baffles to force the flow in a certain direction the cfd analysis of this distribution storage reservoir are done in accordance with a previous study (ghawi and kris 2008 a). the inlet and outlet arrangement was not changed, but three concentric baffles were added to reduce the extent of the stagnant areas. figure 2 and 3 shows the reduction of total stagnant area. 3.2 hydraulic flocculators the primary purpose of a hydraulic flocculator is to generate velocity gradients to stimulate inter particle collisions. hydraulic flocculators are principally characterized by their volume (which determines the time of flocculation) and the water level difference between inlet and outlet (which determines the average velocity gradient). the underlying assumption is that the velocity gradient is proportional to the head loss. the local detail inside the flocculator is however disregarded in the process as only the global volume and global pressure drop is considered. the velocity gradients which are the primary force driving the flocculation process cannot be optimized with conventional methods as the designer has too many degrees of freedom, such as the average water depth, the number and spacing of baffles, the length of the gap at the baffle ends, and the degree to which adjoining baffles overlap (ghawi and kris 2008 b). cfd allows the designer to evaluate the effect of changing the geometric ratios in an attempt to optimize the baffle placement. the channel length for instance can be stretched. or the gap at the end of a baffle can be reduced. this enables the designer to calculate the optimal dimensions of a flocculator for a specific flow rate as described elsewhere. a typical flow pattern is shown in figure 4. 3.3 sedimentation tanks a sedimentation tank is a phase separating device that performs the following functions: firstly it needs to leave a clarified layer of water near the surface in the vicinity of the overflow launders. secondly it needs to settle sludge in the vicinity of the sludge hopper to ensure effective hydraulic removal. in some tanks mechanical removal is done in which case this requirement is less important. the following challenges are faced to achieve an effective design: the presence of suspended matter at the inlet of a sedimentation tank causes density currents and complicates the flow patterns of a sedimentation tank. special precautions are required to manage the density currents that occur as a result of the suspended solids. this is particularly prominent in the case of horizontal settling tanks where only a small portion of the fluid in the tank will move from the inlet towards the outlet at a uniform velocity. particular attention should be given to the inlet of the sedimentation tank. baffles of various forms are used to damp the flow at the inlet to restrict the density current. fluid is also introduced as low as possible to limit density currents. particular attention should be given to the positioning and shaping of hoppers. particular attention should be given to the positioning and shaping of overflow launders. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 102 figure 5 illustrate the model simulated velocities and solids distributions for the modifications tanks. the modelled effluent suspended solids (ess) is summarized in table 1. these simulations demonstrate that the inboard placement of the launder in a rectangular st is a major factor affecting the tank performance (figure 5). the role of the inlet baffle is important in two aspects: 1) this baffle reduces the re-entrainment of already settled liquid into the inlet zone, and 2) it provides a zone for flocculation. the perforated baffle interrupts the bottom density current and helps to redistribute the flow over the tank depth. however this type of baffle may create its own bottom current which then partially negates its positive effect. for these trials the best combination was an inboard launder with a perforated baffle. numerous studies have been conducted (e.g. ghawi and kris 2008c) to investigate the optimal placement of inlet baffles (reaction baffles) in secondary settling tanks. 3.4 potable water storage reservoirs water distribution systems include reservoirs which provide security of supply and even out supply and demand. quality of the water supply is a prime requirement. water quality can be adversely affected by a poor flow pattern in a reservoir, for instance if there are any significant stagnant zones or short-circuiting pathways. cfd has the potential to provide valuable design insight into the hydraulics of reservoirs, which is difficult to acquire from experimental techniques. the flow pattern for the case without baffles is shown by means of velocity vectors in figure 6, which correspond to flow at the floor. after impinging on the reservoir floor, the flow fans out radially. it moves outwards and upwards to the perimeter of the reservoir, is guided around by the perimeter, and then turns back along the main diameter towards the inlet. a significant feature of the flow pattern at the floor is a separation line where the incoming flow lifts off the floor, when it meets water returning in the opposite direction. figure 7 shows residence time of water at the surface. the residence time shows the water is well mixed. for the case with baffles, velocity vectors and residence time for the water surface are shown in figures 8 and 9. there are two parallel baffles, oriented at approximately 40 o to the diameter joining inlet and outlet, and arranged so as to form an s-shaped path for the water. the velocity vectors show that the momentum of the inlet drives a relatively energetic recirculatory flow upstream of the first baffle. outward flow past this baffle lies close to the perimeter wall, and continues along it to the second baffle. between the baffles, and downstream of the second baffle, lie recirculation regions of relatively quiescent water. this maximum residence time is much greater than for the case without baffles. the reason for this is that the baffles tend to suppress the mixing driven by the inlet momentum. the energetic flow near the inlet is largely screened from the remainder of the reservoir by the first baffle. the flow separates off the end of each baffle, giving rise to regions of recirculation within which the residence time remains high (kris and ghawi 2007). conclusions this work deals with the development a specialized strategy for the simulation of the treatment of potable water in different wtps tanks. the strategy is based on the cfd code fluent and exploits several specific aspects of the potable water application. the case considered above demonstrates not only how cfd can be used as a design tool to improve process tank efficiency, but it also demonstrates how simple baffles can make a difference. with tools such as cfd it is not a question to baffle or not to baffle, but rather how to baffle. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 103 references ghawi a. hadi and jozef kris (2007a).” design and optimization of sedimentation tank in slovakia with cfd modeling”. 10th international symposium on water management and hydraulic engineering 2007 with special emphasis on the impact of hydraulic engineering construction on the environment 4 – 9 september 2007. šibenik , croatia ghawi a. hadi, and jozef kris (2007b) “a numerical model of flow in sedimentation tanks in slovakia” third international phd symposium in engineering 25-26 october 2007, hungary university of pollack mihály faculty of engineering pécs, hungary. ghawi a. hadi and jozef kriš (2008a). “analysis of the effect of baffles number on contact tank efficiency”. international doctoral seminar 2008, smolenice castle, 18 20 may 2008 slovakia. pp. 99-105. isbn 978-80-8096-058-2. ghawi a. hadi and jozef kriš (2008b). “numerical modeling of a contact tank at drinking water treatment plant”. international doctoral seminar 2008, smolenice castle, 18 20 may 2008 slovakia. pp. 91-98. isbn 978-80-8096-058-2. ghawi a. hadi, and jozef kris (2008c) “a numerical model of flow in sedimentation tanks in slovakia” pollack periodica, an international journal for engineering and information sciences. doi: 10.1556/pollack.3., vol. 3, no. 2, pp. 59–73 (2008). www.akademiai.com. kris jozef and ghawi a. hadi. (2007) “potable water service reservoirs design improvement using computational fluid dynamics”. 4th iwa specialist conference.on efficient use and management of urban water supply 21-23, may, jejuisland, korea. pp. 1225-1227. kris jozef, and ghawi ali hadi (2007), improved, modeling, simulation and operational parameters of settling tank, 6th international conference, hungary 12-18 august table 1 performance data for modelled settling tank data original perf. baffle (1) inboard launder (2) perf. baf. and inboard launder effluent suspended solids (ess) mg/l 25 10 6 3 (1) perforated baffle distance from inlet = 16m; gap above bed = 0.5 m; height above bed = 1.8 m; porosity = 55% (2) length of launder = 12 m. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 104 figure 1a, 1b & 1c (from top to bottom) different baffle applications. figure 2 flow jetting and recirculation, downstream of chlorine contact tank inlet. mid width velocity profiles for three (3) baffle cases: 1) none (worst); 2) perforated full width; and 3) solid partial width (best). vectors indicate direction, and contours indicate magnitude (m/s). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 105 figure 3 chlorine contact tank depth required to meet the target t10, for the proposed design, and for tanks with a range of modeled physical interventions. figure 4 – highly turbulent zones after baffle tips results in high g-values (red areas). low g-value areas (blue) are due to straightening of flow after each turn. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 106 figure 5 the model simulated velocities and solids concentration (g/l) distributions for the original and modifications tanks (in a vertical section along tank central axis) (a. original tank, b. perf. baffle, c. perf. baffle and inboard launder, and d. inboard launder figure 6 velocity magnitude vectors at floor (m/s). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 107 figure 7 profiles of tracer contours at floor the tank from the cfd model, 1 minute after tracer injections. figure 8 velocity magnitude vectors at surface (m/s) (with baffles). figure 9 profiles of tracer contours at surface the tank from the cfd mode (with baffles). al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 372 the use of recycled concrete as a subbase layer for highways mr. alaa hassoon, college of engineering, university of al-qadisiya. email address: alaa.h_1980@yahoo.com dr. jalal al-obaedi , college of engineering, university of al-qadisiya. email address: jalalalobaedi@gmail.com received 22 may 2014 accepted 16 july 2014 abstract the use of recycled “reclaimed” materials has been increased during the last decades in order to obtain environmental benefits and to reduce the pressure on natural material resources. this paper focuses on using recycled concrete as a subbase material for highways. concrete cubes produced from concrete tests such as compression strength, have been crushed to produce different particle sizes so as to satisfy the gradations requirements according to the iraqi specifications for subbase martial. these recycled samples as well as the samples obtained from ordinary subbase have been subjected to maximum dry density, california bearing ratio (cbr) and atterberg limits tests. the results obtained from maximum dry density test suggested that the waste materials could be compacted to reach reasonable density. the cbr test’s results suggest that the cbr values obtained from recycled concrete is significantly higher than those cbr values obtained from the ordinary subbase. the atterberg tests showed that the waste concrete material is satisfying iraqi specifications for roads and bridges (sorb). 1. introduction and literature review recycling is a process to change waste materials in order to be reused for the same or different purpose of the initial use. recycled materials usually include many kinds of glass, paper, metal, plastic, textiles, and electronics. the tends of societies/countries to replace the old building with new modern ones, caused in creating of millions of tones from the waste construction materials like concrete and asphalt mixes. this produces a new challenge about where to place such materials since such wastes could dramatically affect the environment and land use, if not handled properly. therefore, new research has focused on reusing such waste materials in new industrials and construction projects. such reusing of construction materials may produce more economical resources and help in making friendly “sustainable” environment. however, great attention should be given before recycling to check the suitability of these materials. the uk design manual for roads and bridges (2004) stated that the united kingdom government policy encourages conservation and facilitate the use of recycled “reclaimed” and marginal mailto:alaa.h_1980@yahoo.com mailto:jalalalobaedi@gmail.com http://en.wikipedia.org/wiki/material http://en.wikipedia.org/wiki/glass http://en.wikipedia.org/wiki/paper http://en.wikipedia.org/wiki/metal http://en.wikipedia.org/wiki/plastic http://en.wikipedia.org/wiki/textile http://en.wikipedia.org/wiki/electronics al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 372 materials wherever possible, in order to obtain environmental benefits and reduce the pressure on natural reserves of primary aggregates. several waste materials have been used for highway construction. the most common materials are obtained from recycling of old pavement’s materials such as asphalt and aggregate to build new highways. the old embankment materials such as soil and subbase are also been used for new highways’ projects. the use of recycled asphalt material for hot mix design was adopted since 1980 (al-qadi et al. (2007)). hunsucker and whayne (1992) reported that up to 1992, about 80% of the two-million miles of street and highways of the usa are made of recycled asphalt materials. many researchers have tested the effect of using recycled concrete as aggregate for concrete structures (see for example: malesev et al. (2010), yang et al. (2008), poon et al. (2003) and others). this research focuses on using recycled crushed concrete as a subbase material for highways. therefore, the derived materials have been subjected to most of the required tests for subbase materials according to iraqi specifications for roads and bridges (sorb). 2. methodology in this research work, waste concrete cubes (produces from concrete tests such as compression strength test) have been crushed (see figure 1, which shows the concrete cubes before and after crushing) to produce different particle sizes. this is to satisfy the gradations requirements according to the iraqi specifications for subbase martial. three different subbase types have been obtained from the crushing process; these are types b, c and d. the mid of gradation specifications has been used in the preparation of these three types as shown in table 1). similarly, three types from the ordinary subbase materials have also been prepared for comparison purpose. figure 2 shows the sieve analysis for the selected samples for subbase types b, c and d. table (1) suggests that the best quality of subbase is type “a” which has coarser aggregate and therefore higher california bearing ratio (cbr). this type is usually used for high quality pavements such as those used for freeways and airports. the lowest quality of subbase is represented in type “d” and therefore this type is only used for shoulders. the common type which is used in most highways is type “b”. it should be mentioned here that since subbase type a is rarely used for highway constructions and because the difficulties of obtaining such type from recycling of concrete, no attention is given to use of type a in this study. the adopted tests are:  maximum dry density according to aashto t-180.  california bearing test (cbr) according to aashto t-193  atteberiq limits test according to aashto t-90 3. test results this section explains the results obtained from testing the ordinary subbase samples (i.e. without waste materials) and the samples obtained from the recycled concrete. 3.1. maximum dry density figure (3) shows the relationship between the water content and the maximum dry density. the figure shows the maximum densities obtained from the ordinary subbase are 2.280, 2.250 2.245 gm/cm 3 for types b, c and d respectively. while the corresponding densities for the recycled samples were 2.23, 2.27 and 2.202 gm/cm 3 . http://www.mdpi.com/search?authors=mirjana%20male%c5%a1ev al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 372 generally, the results more or less are identical and that suggest that the subbase material obtained from the recycled concrete can be compacted to reach reasonable density. 3.2. california bearing ratio (cbr) test figure (4) shows the results obtained from the cbr test for both ordinary and waste materials. the results suggest that the cbr values obtained from the recycled concrete give significantly higher cbr values when compared with those values obtained from the ordinary subbase. this could be related with the amounts of dust materials which are usually higher in the ordinary subbase. the whole materials quality maybe another reason since the concrete material should have more resistance for the applied load compared with the ordinary subbase materials. 3.3. atterberg limits atterberg limits define the nature of fine-grained soils and can be used to distinguish between different types of soils. the specifications of subbase materials used for highways (sorb, 2000) stated that the liquid limit and plasticity index should not be exceeding 25% and 6% respectively. for ordinary subbase materials, the results may vary depend on the amount of clay particles. the results obtained from the recycles concrete suggested no values for both plastic and liquid limits which mean zero plasticity index (pi-0). this is because the fine materials within the recycled concrete non-clay materials (i.e. sand particles) which prevent forming a sample tests according the atterberg limits test’s procedure. this is satisfying the iraqi specifications requirements (sorb). 4. conclusions and recommendations this paper focused on using recycled concrete as a subbase material for highways. concrete cubes produces from concrete tests, such as compression strength, have been crushed to produce different particle sizes so as to satisfy the gradations requirements according to the iraqi specifications for subbase martial. these recycled samples as well as the samples obtained from ordinary subbase have been subjected to maximum dry density, california bearing ratio (cbr) and atterberg limits tests. the results obtained from maximum dry density test suggested that the waste materials could be compacted to reach reasonable density. the cbr test’s results suggests that the cbr values obtained from recycled concrete are significantly higher than those cbr values obtained from the ordinary subbase. the atterberg tests showed that the waste concrete material is satisfying iraqi specifications for roads and bridges (sorb). therefore, it could be concluded here that the recycled concrete could be used as a subbase material for highways. however, further tests may be needed to show the effect of having different proportions from mixing the recycled concrete and ordinary subbase. 5. references  american association of state highway and transportation officials aashto. standard specifications for transportation materials and methods of sampling and testing (2013). washington dc.  al-qadi, i., elseifi, m. and carpenter, s. h. (2007). “reclaimed asphalt pavement-a literature review”. illinois center for transportation. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 372  design manual for roads and bridges dmrb (2004), “chapter twoprovisions for the use of secondary and recycled materials”, united kingdom.  hunsucker, d. q. and whayne, l. (1992). “recycled materials in kentucky highway construction” research report, kentucky transportation center.  malesev, m,radonjanin, v. and marinkovic, s. (2010). “recycled concrete as aggregate for structural concrete production” journal of sustainability, vol(2), issue (5).  poon, c.s.; azhar, s.and kou, s.c. (2003) “recycled aggregates for concrete applications”. proceeding of the materials science and technology in engineering conference—now, new and next, hong kong, china, 15–17.  standard specifications for roads and bridges (2003), the state corporation for roads and bridges, iraq.  yang, k.h.; chung, h.s. and ashour, (2008). “influence of type and replacement level of recycled aggregates on concrete properties”. aci mater. j. 2008, vol(3),p.p. 289-296. table (1): subbase types according to iraqi specifications (sorb, 2003) gradation sieve size percent of passing type a type b type c type d 75mm 011 50mm 59-011 011 25mm 59-59 011 011 9mm 01-59 01-59 9159 51-011 4.75mm 59-99 01-51 09-59 9159 2.36mm 05-05 50-05 55-95 05-55 0.3mm 505 0055 0055 50-05 0.075mm 55 909 909 951 cbr (minimum) 45 35 30 20 liquid limit (maximum) 25 for highways and 35 for shoulders plasticity index (maximum) 6 for highways and 9 for shoulders figure (1) concrete cubes before and after crushing http://www.mdpi.com/search?authors=mirjana%20male%c5%a1ev http://www.mdpi.com/search?authors=vlastimir%20radonjanin http://www.mdpi.com/search?authors=sne%c5%beana%20marinkovi%c4%87 al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 377 figure (2) the gradations of used subbase figure (3) maximum dry density results figure (4) california bearing ratio (cbr) results 0 20 40 60 80 100 120 0.01 0.1 1 10 100 p e rc e n t o f p a ss in g ( % ) sieve size (mm) type b type c type d 2.14 2.16 2.18 2.2 2.22 2.24 2.26 2.28 2.3 2.32 types b type c type d m a x im u m d ry d e n si ty ( g m /c m 3 ) subbace type ordinary subbase recylced subbace 0 10 20 30 40 50 60 70 80 ordinary subbase recycled subbace specifications c b r ( % ) type b type c type d oxygen and nitrogen separation from air using zeolite type 5a. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 oxygen and nitrogen separation from air using zeolite type 5a. dr.hussein h. hamed department of fuel and energy, technical college-kirkuk, iraq husseinmsn@yahoo.com received 24 november 2014 accepted 20 january 2015 abstract an adsorption (psa) unit consist of two – tubes columns pressure swing, (6cm diameter and 70cm bed length) and a dryer part (12cm diameter and 27cm) filling with activated alumina (al2o3) have been constructed to study the separation of oxygen and nitrogen from air using commercial 5a zeolite under the effect of adsorption pressure (1 to 6 bar), adsorption time (20s), product flow rate (1 liter/min) on the product oxygen purity. for the case of 2-column, 4-step operation, the results show that an optimum concentration product of oxygen was 76.9%purity,at the adsorption pressure 4bar, temp 17.4 o c.nitrogen optimum production was78.8% purity, at 1 bar. key words: pressure swing adsorption (psa), oxygen production using zeolite 5a, air separation, equilibrium adsorption, oxygen concentrator unit. .5aفصل االوكسجين والنتروجين من الهواء باستخدام زيواليت نوع د.حسين حبيب حميد قسم هندسة تقنيات الوقود والطاقة –كركوك –الكلية التقنية : الخالصة سم( وجزء مجفف 07سم وطوله 6الواحد ) قطرالعمود، اسطوانيين بعمودين (psa)تم تصنيع منظومة لالمتزاز بتغيير الضغط من الهواء والنتروجين لدراسة فصل االوكسجين( al2o3سم ( مملوء بمادة اوكسيد االلمنيوم المنشط) 10سم وطول 21بقطر) تمت دراسة تاثير ل الضغط( ، التشغيل ذات االربعة خطوات )بوجود خطوة تعادة استعملت طريق .5aباستعمال الزيواليت لتر/دقيقة( ولحالة 2ثانية( ومعدل جريان ) 17الضغط التشغيلي للمنظومة على نقاوة االوكسجين والنتروجين المنتج بزمن امتزاز ) بار ودرجة 4( لضغط تشغيلي %76.9عمودين واربعة خطوات تشغيلية كانت النتائج تشير الى ان تركيز االوكسجين المنتج ) سيليزية. 20.4بار ودرجة حرارة 2%(عند ضغط 07.7وبالنسبة للنتروجين وصلت النقاوة الى) سيليزية. 20.4رة حرا introduction: adsorption processes are often identified by their method of regeneration. temperature-swing adsorption (tsa) and pressure swing adsorption (psa) are the most frequently applied process cycles for gas separation. the basic difference between the two processes is shown schematically in figure (1). because changes in pressure can be brought about more rapidly than changes in mailto:husseinmsn@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 temperature, pressure-swing regeneration can be used with shorter cycle-times than was possible with temperature-swing. this, in turn, allows smaller beds to be used and consequently a smaller inventory of adsorbent is needed in the system.[moghadazadeh,et.al,2008,.masoud,2013,kirkothmer,1998]. atypical total cycle time for the psa process is between one to several minutes [sircar, 1988], compared to the tsa process cycle time of hours. pressure swing adsorption (psa) processes, first suggested by skarstrom in the form of a ‘heatless drier’ have found widespread application in hydrogen purification and air separation, as well as in air drying[skarstrom, c. w.,1959,skarstrom, c. w.,1960,skarstrom, c. w.,1972]. the psa process could be described briefly as follows: two columns operate semi-continuously in four stages to supply the desired purity and flow rate of oxygen. adsorbents are selectively chosen to provide for the most beneficial design. the psa stage operation is described in figures 2-5[ruthven, et.al ,1994,oxygen generating system intl. web site,2007] as following; -stage 1: compressed air is fed into the first bed. nitrogen molecules are trapped, while oxygen is allowed to flow through fig(2). -stage 2: when the adsorbent in the first bed becomes saturated with nitrogen , the air flow feed is directed into the second bed fig(3). -stage 3: the adsorbent adsorbs nitrogen in the second bed. the first bed is depressurized allowing nitrogen to be purged out of the system and released to the atmosphere fig(4). -stage 4: the process starts over. compressed air is once again fed into the first bed. the second bed is depressurized releasing argon and nitrogen molecules to the atmosphere. the process is repeated continuously producing a constant flow of purified oxygen fig(5). a very important improvement was the introduction of the pressure equalization step. [pramuk, et.al,1964,berlin, 1966,wagner, 1969].the pressure equalization, using a product-enriched current, leads to a significant economy in energy consumption, since less mechanical energy is required to re-pressurize the column at low pressure, after the purge stage. the product recovery is, in this way, also increased because less feed gas is necessary to re-pressurize the column.[cruz, et.al,2003]. oxygen production (purity below 95%) from air, using nitrogen selective zeolites of type a (5a) or x (13x-nax, lix, or lilsx), by means of pressure swing adsorption (psa) processes has noticeably increased in the past decade. however, the concentration of the product is limited to 95% oxygen, because of the presence of argon in air, since these adsorbents present similar adsorption capacities for oxygen and argon.[santos,2007]. zeolites have the unique ability to adsorb n2 more strongly than o2 (i.e., by a factor of 2 or more in terms of pure component adsorption amounts). the main reason for this is the interaction between the quadruple moment of n2 and the cation that is attached to the zeolite framework.[rege, et.al,1997]. nitrogen and oxygen are, respectively, the second and third largest man-made commodity chemicals today. since 1920s, n2 and o2 have been produced by cryogenic distillation of air. since 1980s, adsorption (i.e., pressure swing adsorption or psa) has been adopted rapidly and increasingly for air separation. approximately 20% of air separation is presently accomplished by psa.[rege, et.al,1997]. commercial psa technology can be used to produce an oxygen-enriched stream containing 8095% oxygen which finds application in biological wastewater treatment, medical use, enhanced combustion in furnaces and cupolas, etc.[sircar, et.al,1998]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 741 currently, design of psa systems relies heavily on experimental data for the system of interest. experiments are conducted over a wide variety of process condition (pressure, purge-to-feed rates, steps times, feed and product flow rate, etc.) for specified adsorbent and cycle. the aims of the present work are: 1. the objective of this project is to determine whether or not it is feasible to build an oxygen supply device using 5a zeolites to separate oxygen and nitrogen from air, using two bed columns, packed with commercial 5a zeolite and its properties shown in table(1) [anant,et.al.2013]. 2. studying the effects of adsorption pressure on the performance of psa unit, using two columns 4-steps equalization modification cyclic operations. the performance is characterized by o2 and n2 product purity, maximum operating pressure 6 bar. experimental work: the experimental work includes two parts, one for air drying and another for oxygen and nitrogen separation from air using zeolite type 5a to produce pure oxygen and nitrogen. all the runs are conducted at ambient temperature. air separation by pressure swing adsorption (psa) process: devices; air separation by pressure swing adsorption to produce pure oxygen and nitrogen performed using two columns 4-steps equalization modification cyclic operations. the equipment used in the present work consists of: 1two-tubes adsorption columns of aluminum type (a) of 6cm diameter and 70cm length. 2product flow meter (flow rate of 0.1 to 1 liter/min, afr2000, xcpc2000). 3the drying unit is composed of one galvanized steel columns, which are packed with activated alumina (2.395kg) with properties shown in table (2). the length of column (l) is 27 cm and its diameter (d) is 12cm fig.(6). 4digital oxygen meter with a polar graphic type probe with an incorporated temp. sensor which serves for precise dissolved oxygen(do) and temp. measurement. model : do-5510ha with specifications shown in table (3).fig.(7). 5purge flow meters (maximum flow rate 10l/min, type yr-88, manufacture in china). 6pressure regulator (1 to 10 bar). 7solenoid valves on the feed line, (model 2w-200-20,3/4" in size, 220v, 50hz, 28va, temp (-5ºc-80ºc),h.a.k pneumatic). 8equalization valves ( 1/8" in size, 220v, 50hz, type122k232,30bar,lucifer switzerland.). 9pressure gauges (1-8 bar, china manufactured). 10control panel(fig(8)) 4 steps, which is working as follow; a-the first 20 seconds, v1 (2 and 4 valve) is open. the remaining valves are closed. b-for 10 seconds, v2 (5 and 6 valves) are open. the remaining valves are closed. c-for 20 seconds, v3 (1 and valve 3) open. the remaining valves are closed. d-for 10 seconds, (5 and 6 valves) open. the remaining valves are closed. 11each column contains 1.430kg of zeolite 5a. 12flow diagram of psa unit fig.(9) , psa unit picture fig.(10). experimental procedure: pressure swing adsorption (psa) is a technology used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 751 adsorbent material. it operates at near-ambient temperatures and differs significantly from cryogenic distillation techniques of gas separation. specific adsorptive materials (e.g., zeolites, activated carbon, molecular sieves, etc.) are used as a trap, preferentially adsorbing the target gas species at high pressure. the process then swings to low pressure to desorb the adsorbed material. effect of higher operation pressure studied on oxygen and nitrogen purity in laboratory scale psa unit from 1 to 6 bar using zeolite 5a. in this system binary mixture (n2/o2) (79/21 vol %) used as a feed stream as following: 1air compressor started until the tank pressure reached the desired pressure (4bar for o2, 1 bar for n2). 2operate the control panel. 3then the air enters to dryer to drying from moisture and cleans it from impurities. 4regulate the air by the air regulator to the require pressure. 5the air enters to the column no.1 (c1) from the top, the zeolite adsorbs nitrogen and the other gases and oxygen rich gas flow from the bottom. 6the oxygen from column1 divided into two streams. 7the second stream goes to the valve no.5 to equivalent pressure between the column no.1 and column no.2. 8the third stream goes to the check valve no.1 that is reversal direction of it flow, therefore goes to the check valve no.3 that is the same direction of its flow and allow it to flow across it. 9from check valve no.3 divided into two streams. 10the first stream goes to the flow meter no.2, and the product oxygen goes to oxygen meter to measure its concentration and temperature. 11the second stream goes to the flow meter no.1 then recycled. 12the recycle is entering from the bottom of column no.1 to desorb the nitrogen from the zeolite to clean it, and to be ready to another adsorption process of oxygen. 13the nitrogen out from the top of the column no.1, and valve no.1 is open then nitrogen out from it. 14the processes from step 5 to 14 is the same process in the column no.2,but when the first column is adsorbed nitrogen and product oxygen the second column is desorbed nitrogen from zeolite by the oxygen recycle. 15and when the second column is adsorbed nitrogen and product oxygen the first column is desorbed nitrogen from zeolite by the oxygen recycle. result and discussion; the separation of mixtures of fluids using zeolitic as selective adsorbents may be accomplished in three fundamentally different modes; 1-when the physical size and or shape of the molecules of the fluid materials to be separated are sufficiently different and a molecular sieve having a suitable pore size is available a separation is possible based on the acceptance-exclusion phenomenon. 2-when the physical size and or shape of the molecules to be separated are different and a molecular sieve is available having a pore opening through which the larger molecules pass only with difficulty, a separation is possible which is kinetically controlled. some such separations are inverse to the separation effected when the molecules all can freely enter the pore system. 3-when the physical size and or shape of the molecules to be separated are not sufficiently different to either be separated by the acceptance-exclusion phenomenon or the kinetically controlled http://en.wikipedia.org/wiki/adsorbent http://en.wikipedia.org/wiki/distillation#industrial_distillation http://en.wikipedia.org/wiki/zeolites http://en.wikipedia.org/wiki/activated_carbon http://en.wikipedia.org/wiki/molecular_sieves al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 757 situation but all freely enter the pore system the separation depends on the forces of adsorption between the molecular sieve and the different molecules. pressure swing adsorption processes rely on the fact that under high pressure, gases tend to be attracted to solid surfaces, or "adsorbed". the higher the pressure, the more gas is adsorbed; when the pressure is reduced, the gas is released, or desorbed. psa processes can be used to separate gases in a mixture because different gases tend to be attracted to different solid surfaces more or less strongly. if a gas mixture such as air, for example, is passed under pressure through a vessel containing an adsorbent bed of zeolite 5a that attracts nitrogen more strongly than it does oxygen, part or all of the nitrogen will stay in the bed, and the gas coming out of the vessel will be enriched in oxygen. when the bed reaches the end of its capacity to adsorb nitrogen, it can be regenerated by reducing the pressure, thereby releasing the adsorbed nitrogen. it is then ready for another cycle of producing oxygen enriched air. therefore, it is noted fig.(12), where the intersection of each of the oxygen production line and nitrogen, one point under the pressure of 2 bar while the intersection of two gas (n2 and o2) production line in figs.(13.16) with two points under the pressure of 3 and 6 bar sequentially and the intersection of the production of gases under the pressure of 5 bar in three points fig.(15). through practical experience shows that many factors influenced by the production of gases from the most important dimensional design own column absorption and surface area of the material adsorbent (zeolites 5a) where the pressures (2, 3, 5 and 6) bar were unsuitable to work. because of purity is increased with increasing of purge and after reaching to a peak, decreasing. as we know, purging the adsorption bed, help the adsorbent regeneration and increase its capability, but increasing the amount of this stream more than its sufficiency causes the adsorption of oxygen on the adsorbent because of its high vapor pressure in the column and the efficiency of adsorbent will be decreased. finally as we see from fig.(14), in short cycle time, high purity will be achieved. optimum oxygen concentration 76.9%vol after 4 min operation time. because there is not enough time for oxygen adsorption instead of nitrogen and verse reverse for nitrogen the optimum case is clear in fig.(11) which is will be 78.8% after 2 min under 1 bar operating pressure. conclusion and recommendation the following goals were met with the portable oxygen concentrator from the initial estimates; purity: 76.9% oxygen,78.8% (from the first stage). cost: $4200 (under $5000). weight: 75kg. small: estimated .2m x 2m x 1m thus from the above information, it can be see that a competitive / light weight portable oxygen concentrator. it is useful for using in welding machine and it is small enough to take on an airplane. it is a good idea to study the effect of ozone on the oxygen and nitrogen production. refrences [1] anant j. songsde and r. v. prajapati.,”pressure swing adsorption a cleaner techniques to reduce emission”, ijsrd,vol.1,issue 3, (2013). http://en.wikipedia.org/wiki/air http://en.wikipedia.org/wiki/zeolite http://en.wikipedia.org/wiki/nitrogen http://en.wikipedia.org/wiki/oxygen http://en.wikipedia.org/wiki/nitrogen al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 751 [2] berlin, n. h., “method for providing an oxygen-enriched environment”. us patent no. 3 280 536, (1966). [3] cruz, p., santos, j. c., magalh˜aes, f. d. and mendes, a.," cyclic adsorption separation processes: analysis strategy and optimization procedure", chem. eng. sci., 58, 3143 – 3158, (2003). [4] kirk-othmer, encyclopedia of chemical technology, volume 1,4 th edition, john-wiley & sons (1991-1998). [5] masoud mofarahi, ehsanjavadishokroo, "comparision of two pressure adsorption process for air separation uzing zeolite 5a and zeolit 13x".petrolum & coal 55(3)216-225,( 2013). [6] moghadazadeh zahra, towfighijafar, and mofarahimasoud, "study of a four bed pressure swing adsorption for oxygen separation from air", in. j. chem. bio. eng. 1.3 (2008). [0] pramuk, f. s., hoke, r. c., &skarstrom, c. w., " pressure equalization depressurizing in heatless adsorption". us patent no. 3 142 547, (1964). [7] pressure swing adsorption technology.retrieved march 15,(2007),from oxygen generating system intl. web site: http://www.ogsi.com/pressure_swing_adsorption_technology.php.(2007). [9] rege, s.u., and yang, r.t.," limits for air separation by adsorption with lix zeolite", ind. eng. chem. res., 36, 5358-5365, (1997). [27] ruthven, d. m.; farooq, s.; knaebel, k. s. "pressure swing adsorption". vch publishers: new york, (1994). [12] santos j.c., cruz p, regala t., magalhaes f.d., and mendes a., "highpurity oxygen production by pressure swing adsorption", indengchem 46, pp 591 599, (2007). [11] sircar, s.,"air fractionation by adsorption, separation science &technology", 23(14 & 15), pp. 2379-2396, (1988). [13] skarstrom, c. w., "use of adsorption phenomena in automatic plant-type gas analyzers". ann. n.y. acad. sci. 72, 751,(1959). [14] skarstrom, c. w., u.s. patent 2,444,627 (to esso research and engng co.), (1960). [15] skarstrom, c. w., "heatless fractionation of gases over solid adsorbents", in recent developments in separation science, vol. 2. crc press, cleveland, ohio., 1972.2, 95-106 (1972). [16] wagner, j. l.," selective adsorption process". us patent no.3430418 (1969). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 751 table (1): 5a zeolite properties. table (2): activated alumina properties. surface area , m 2 /g 330 total pore volume, cm 3 /100g 44 diameter of particles mm 5 shape sphere bulk density, kg/m 3 785 table (3): oxygen meter model: do-5510ha specifications custom one – chip of microprocessor lsi circuit. circuit dual function meter ' s display, 13mm (0.5 ,, ). super large lcd display with contrast adjustment for best viewing angle. display 0 to 20.0 mg/ l (liter). dissolved oxygen measurement & range 0 to 100.0 % oxygen in air 0 to 50 o c temperature 0.1 mg / l dissolved oxygen resolution 0.1 % o2 oxygen in air 0.1 o c temperature ±0.4 mg / l dissolved oxygen accuracy ( 23 ± 5 o c ) ±0.7 % o2 oxygen in air ±0.8 o c / 1.5 o f temperature the polar graphic type oxygen probe with an incorporated temperature sensor. sensor structure 0 to 50 o c automatic temperature probe compensation & adj. 0 to 39 % salt salt 0 to 3900 meter height ( m.t) records maximum, minimum and average readings with recall. memory recall al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 754 figure (1): temperatureswing and pressure-swing cycles. figure (2): psa stage1 figure (3): psa stage2 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 755 figure (4): psa stage3 figure (5): psa stage4 figure (6): drying unit. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 751 figure (7): oxygen meter unit. figure (8): control panel 4 steps unit. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 751 figure (9): flow diagram of psa unit figure (10): psa unit comp o2.m d a.r v p.g ch.v f.m c compressor oxygen meter dryer air regulator valve pressure gauge check valve flow meter column al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 751 effect of metakaolin in self compacting concrete with sand containing sulphates year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 426 effect of sulfates in fine aggregate on some properties of self compacting concrete incorporating high reactive metakaoline haider k. ammash1, haider m. al-baghdadi2, nabeel hasan ali al-salim3 1department of civil eng., college of eng., al-qadisiyia university, iraq 2&3 department of civil eng., college of eng., babylon university, babylon, iraq abstract fine aggregate contaminated with interior sulfates is an important problem of concrete manufacture in iraq. it is difficult to obtain well graded fine aggregate with sulfates content within standard specifications. the main objective of this study is to investigate the effect of internal sulfates in sand on some properties of self compacting concrete (scc) by adding natural gypsum to fine aggregate as a partial replacement by weight. in this work, two basic categories of selfcompacting concrete are used: (scc) incorporating limestone powder (lsp) and scc incorporating 10% high reactivity metakaolin (hrm) class n plus limestone powder(lsp) .four levels of sulfates contents in fine aggregate were investigated, these levels were ( 0.37, 0.5, 1.0, and 1.5)% which it is equal to(3.74, 3.99, 4.96 and 5.93)% by weight of cement for mixes contained limestone powder (lsp) and it is equal to (3.76, 4.01,4.98 and 5.96) % by weight of cement for mixes contains high reactivity metakaolin (hrm) class n plus limestone powder(lsp). the experimental program is divided into two parts; the first part is devoted to produce self compacting concrete by using superplasticizers and fillers then determine the workability. different test methods are adopted such as slump flow and t50 cm, v-funnel, vfunnel at t5 minutes, l-box and sieve segregation test. the second part is devoted to study the mechanical properties such as the compressive strength and splitting tensile strength. the results obtained from this work show that the optimum gypsum content was 0.5% by weight of fine aggregate for all mixes which gives increases in the compressive strength by a range(5.9 -10.1)% and in the splitting tensile strength by a range (1.2 – 8.5 )% for mixes of (ssc) with (lsp) and (lsp +hrm). keywords: scc, limestone powder (lsp), high reactivity metakaolin(hrm), sulfates contents%, compressive strength , splitting tensile strength , l-box , v-funnel, slump flow test, sieve segregation test. الخالصة ف�ي الع�راق. فم�ن ألص�عوبة أيج�اد رك�ام التي تواجه ص�ناعة الخرس�انة ل المهمةمن المشاكهي الكبريتات الداخلية أمالح وجودإن أم�الح أله�دف م�ن ه�ذا العم�ل ه�و دراس�ة ت�أثير الكبريت�ات . أم�الح ناعم مط�ابق للمواص�فات م�ع ح�دود المواص�فات الحالي�ة لح�دود عمإل�ى الرك�ام الن�ابإض�افة الج�بس الطبيع�ي لخرس�انة ذاتي�ة ال�رصل ف�ي الرك�ام الن�اعم عل�ى بع�ض الخ�واص الميكانيكي�ة الكبريتات من الخرسانة ذاتية الرص وهي : خرسانة ذاتية ال�رص حاوي�ة أساسين نوعينفي هذا البحث تم استعمال ه.وزن كإحالل جزئي من ت�م % ميتاك�اؤلين ع�الي الفعالي�ة و مس�حوق الحج�ر الجي�ري10على مسحوق الحجر الجيري و خرس�انة ذاتي�ة ال�رص حاوي�ة عل�ى وال����ذي يس����اوي ف����ي الرك����ام الن����اعم .%(and 1.5 ,1.0 ,0.5 ,0.37) دراس����ة أرب����ع نس����ب لمحت����وى الكبريت����ات 4.01 ,3.76)إلىكمادة مالئة ومساوي الحجر الجيريللخلطات التي تحوي على % من وزن اإلسمنت(3.74,3.99,4.96,5.93) ,4.98 and 5.96) % برن�امج . الجي�ري% ميتاكاؤلين عالي الفعالية و مسحوق الحجر 10للخلطات التي تحوي من وزن السمنت year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 427 ت�م المادة المالئة ثم أيجاد قابلية التش�غيل .و الملدنات ألجزء األول هو أنتاج خرسانة ذاتية الرص باستعمال ; جزأينألعمل يقسم إلى ,دقائق 5بعد مرور v القمع على شكل حرف ,vفحص جريان الهطول, القمع على شكل حرف استخدام طرق فحص مختلفة مثل والخواص الميكانيكي��ة مث��ل مقاوم��ة االنض��غاط ألج��زء الث��اني ه��و دراس��ة. فح��ص مقاوم��ة االنع��زال lالص��ندوق عل��ى ش��كل ح��رف % م�ن وزن ألرك�ام 0.5محت�وى الج�بس األمث�ل ف�ي الخرس�انة ذاتي�ة ال�رص عن�د نس�بة إن أظهرت النت�ائج .االنشطارشد مقاومة )% ف��ي مقاوم��ة ش��د 8.5 -1.2)% و( 10.1-5.9قاوم�ة االنض��غاط تراوح��ت ب�ين (لك��ل الخلط��ات والت�ي تعط��ي زي��ادة ف��ي م الن�اعم )% ف�ي 7.8 – 1.4تت�راوح ب�ين ( في محتوى الكبريتات بعد ألنسبة المثلى يسبب تن�اقص ف�ي المقاوم�ة اإلضافية زيادةال .االنشطار و )% 1 – 0.37بريتات في الركام الناعم م�ن (عندما تزداد نسبة الكفي مقاومة شد االنشطار )% 3.3 -2.1مقاومة االنضغاط و ( ) % في مقاومة شد االنشطار عندما تزداد نسبة الكبريتات في الركام الناعم م�ن 5.6-3.8)% في مقاومة االنضغاط و (9.9 -6.4( ) % على التوالي.1.5 – 0.37( introduction self–compacting concrete (scc) represents one of the most outstanding advances in concrete technology during the last decade. at first developed in japan in the last 1980s, scc meanwhile is spread all over the world with a steadily increasing number of applications [holschemacher, 2002]. self compacting concrete (scc) was developed to respond to the need for concrete that can improve durability while eliminating the need for compaction and vibration work. scc can compact itself into complicated formwork and congested structural elements under its own weight without the need for mechanical vibration. it needs to be both highly deformable and resistant to segregation and bleeding [okamura, h. & ouchi, 1999]. due to the highly flowable nature of self – compacting concrete, care is required to ensure excellent filling ability, passing ability and adequate stability [sonebi, grünewald , and walraven , 2007] this ability is achieved by ensuring suitable rheological properties of fresh concrete: a low yield stress value associated with adequate plastic viscosity. fresh concrete can easily attain high flowability by simply increasing the water-to-binder (w/b) ratio. however, increasing the w/b ratio alone could lead to concrete segregation and less durability. thus, in order to successfully develop scc, mineral and chemical admixtures, e.g., pozzolans, limestone powder, superplasticizer, and viscosity-modifying admixture (vma), need to be added to the mix to prevent segregation and enhance the workability of scc [suksawang, nassif, najm, 2006]. sulfates cause concrete or mortar deterioration when it exists in excessive amount. this phenomenon is called sulfate attack. the sulfate reacting with ca(oh)2 and with calcium aluminate hydrate (c-a-h). the products of reactions, gypsum and calcium sulphoaluminate have a considerably greater volume than the compounds they replace, so that the reactions with the sulfates lead to expansion and disruption of the concrete. sulfate in fine aggregate is a major problem encountered in the middle and southern part of iraq. most of the sulfate salts in fine aggregate are composed of calcium, magnesium, potassium and sodium sulfates. calcium sulfate is the most predominant salt present in iraqi fine aggregate. it is usually found in fine aggregate as gypsum. about 95% of sulfates in fine aggregate are in the form of calcium sulfates because of the low solubility of this type of sulfate [al-samerai ,1977]. sulfates may come either from raw materials and or from gypsum added to cement at grinding stage. [al-qaisi, w.a.,-1989] stated that the activity of gypsum is dependent on its fineness. in their study on the effective sulfate content in concrete ingredients [al-rawi, ali, shallal, and alsalihi,1997],pointed out that the effect of so3 existing in cement on compressive strength of concrete is about two times more that in fine aggregate and effect of the latter is about two times more that in coarse aggregate. they attributed this to the fine particle size distribution of cement compared with fine aggregate and coarse aggregate. in a later study by [al-rawi, 2000], to develop the concept of effective sulfate content, he found that the effectiveness of sulfates increased with increased fineness of fine aggregate. he suggested a formula to account for the effectiveness of year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 428 sulfates in fine aggregate depending on its fineness modulus. he showed also that the same formula is applicable. the sulfate content in fine aggregate contains sulfate higher than the acceptable limits in most of the fine aggregate in middle east countries [al-kadhimi and hamid, 1983]. [alrawi ,1997], investigated the effect of the gypsum content of cement on several engineering properties of concrete cured by accelerated and normal methods. he stated that increased gypsum content results in a significant decrease in the slump of concrete and that there is an optimum gypsum content, considerably higher for accelerated cured concrete than for normally cured concrete, at which maximum strength is obtained. the optimum gypsum content under accelerate curing conditions may be used without risk of reduction in the durability of concrete caused by excessive, delayed expansion. [alrawi and abdul latif ,1998], suggested a new test called "compatibility test" to investigate the possibility of using sands with relatively high (so3) contents with suitable cement without deleterious effect on concrete. the work was carried out on seven cements, three ordinary portland cement, three sulfate resisting cements and white cement. the sand used had so3 contents between 0.18% and 1.5% and the mix is designed to give a compressive strength of 30 mpa at 28 days. the results show that the so3 content in sand gives the maximum concrete strength which differs from one cement to the other ranging from (0.18% to 1.5%) depending on the chemical composition and fineness of cement. [alwash, 2005] , the percentage reduction in compressive strength of the mix with opc and sand of zone 2 which contains sulfate of 1.5% by weight of it compared with the reduction in strength of the mix with opc and sand of zone 4 which contains sulfate of 1.5% by weight of it at ages 7, 28 and 56 days was (30.86%-37.7%), (10.47%-17.9%) and (2.29%-8.16%) for air curing and (23.6%-28.4%), (7.7%-13.4%) and (5.8%-5.5%) for moist curing and the influence of sulfates on the splitting tensile strength and static modulus of elasticity is found to be somewhat similar to that of compressive strength. [hussain, 2008], investigated the effect of internal sulfates in fine aggregate on some mechanical properties of self compacting concrete with different types of filler such as limestone powder, pigment and hydrated lime. the investigated mechanical properties were compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, the ultrasonic pulse velocity and schmidt rebound hammer tests. the author founded that there is an optimum gypsum content at which the strength is maximum .further increase in so3 content beyond the optimum causes a decrease in strength and non destructive tests. high reactivity metakaolin is a supplementary cementitious material (scm) that conforms to astm c 618 – 05, 2005 [astm c 618-05] class n pozzolana specifications. high reactivity metakaolin is unique in that it is not the by – product of an industrial process nor it is entirely natural; it is derived from a naturally occurring mineral and it is manufactured specifically for cementing applications [caldarone, m.a., gruber, k.a. and burg, r.g.,-1994]. unlike by – product pozzolans which can have variable composition, high reactivity metakaolin is produced under carefully controlled conditions to refine its color, remove inert impurities and control particle size distribution [brooks and johari, 2001]. [wild, khatib and jones, 1996] reported that the strength of high reactivity metakaolin – superplasticizer mixes were greater than the strength of superplasticizer mixes at all ages. they tested concretes ranging from 1 to 90 days in age, produced at a w/cm of 0.45. they found that 20% replacement with hrm was optimal for achieving maximum long – term strength enhancement. 1. experimental work year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 429 the purpose behind this study is to find out the effect of internal sulfates in sand on some properties of self compacting concrete (scc) by adding natural gypsum to fine aggregate as a partial replacement by weight of fine aggregate. two basic of self-compacting concrete mixes are used: (scc) incorporating (lsp) and scc incorporating (10% (hrm) class n+ (lsp)) and curing time for (28, 56 and 90 days) were conducted. four levels of so3 contents in fine aggregate were investigated; these levels were 0.37%, 0.5%, 1.0% and 1.5% by wt. of fine aggregate. the tests were conducted in order to view the differences in behavior during the fresh state as well as the hardened state. the slump flow, l-box, v funnels and sieve segregation test were performed on concrete in the fresh state. the concrete specimens were tested at ages (28, 56 and 90 days) for compressive strength and splitting tensile strength. the details of each concrete mix were summarized in (table 1). 2. materials 2.1 cement the used cement was ordinary portland cement named as tasluja bazian. the cement was tested and checked according to (iqs no.5 /1984). the chemical and physical tests were conducted in construction materials laboratory of babylon university. 2.2 fine aggregate (sand) al-akhaider natural fine aggregate with fineness modulus (2.64) was used throughout this work. . results indicate that the fine aggregate grading, physical properties and the sulfate contents are within the requirements of the iraqi specifications (iqs no.45 /1984). 2.3 coarse aggregate (gravel) rounded coarse aggregate of passing sieve size 10 mm from alnibaee quarry is used. the coarse aggregate was washed, and then stored in air to dry. the grading of this aggregate which conforms to the iraqi specification (iqs no.45/1984). the specific gravity and sulfate content and absorption of coarse aggregate are within the requirements of the iraqi specifications (iqs no.45 /1984). 2.4 water tap water is used throughout this work for both mixing and curing of concrete. 2.5 superplasticizer superplasticizer (sp) is an essential component for scc production. it is used to achieve high workability and stability for (scc). according to (astm c494), this sp is classified as type glenuim 51. 2.6 limestone powder (lsp) limestone powder is a white ground material from limestone that found in different regions in iraq, and usually used in the construction processes. limestone powder which has been brought from local market is used to increase the amount of powder (cement + filler), the fraction less than 0.125mm will be of most benefit. this filler conforms to (bs 7979). the chemical analysis of lsp is listed in (table 2). 2.7 gypsum gypsum is added to the fine aggregate to obtain the required so3 content. the added gypsum is natural gypsum rock (brought from kufa cement factory). it was crushed and ground to obtain nearly the same gradation set of fine aggregate used in the mix. this gypsum was used as a partial replacement by weight of fine aggregate with limited percentages. the quantity of natural gypsum was calculated and added to the fine aggregate according to the following equation [al-kadhimi, t. k. and hamid, f. a.,1983]: year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 430 w=(r – m) s / n (1) where: w= the weight of natural gypsum needed to be added to fine aggregate. r= the percentage of so3 % desired in fine aggregate. s = the weight of fine aggregate in mix. m = the actual so3 in fine aggregate (0.37 %). n= the percentage of so3 % in the used natural gypsum. 2.8 high reactivity metakaolin (hrm) high reactivity metakaolin is one of the recently developed supplementary cementing materials. it is produced by calcining purified kaolin clay at a specific temperature range to drive off the chemically bound water and destroy the crystalline. the used (hrm) was prepared by burning the kaolin clay at 700°c for whole one hour then left to cool down. the chemical and physical properties of (hrm) are listed in (table 3). 3. mixing procedure the required amount of gypsum was added to the fine aggregate, in order to obtain the desired level of so3 in the sample then fine aggregate and gypsum were mixed until a homogeneous mix is obtained. high reactivity metakaolin powder was mixed with the quantity of cement with the aid of trowels, until the hrm particles were thoroughly dispersed between cement particles. mixing procedure is important to obtain the required workability and homogeneity of the concrete mix. concrete was mixed in drum laboratory mixer, with a capacity of 0.05m3. before starting to mix, it is necessary to keep the mixer clean, moist and free from previous mixes. the procedure used for mixing the batches was as follows [emborg m., -2000]: 1adding the fine aggregate to the mixer with 1/3water, and mixing for 1minute. 2adding the powder (cement + filler) with another 1/3 mixing water, and mixing for 1 minute. 3after that, the coarse aggregate is added with the last 1/3mixing water and 1/3 of superplasticizer, and mixing for 1.5 minute then the mixture is left for 1.5 minute for rest. 4then, the remaining 2/3 of the superplasticizer is added and mixed for 1.5 minute. the scc mix proportions are summarized in (table 4). 4. test methods for fresh (scc) fresh concrete tests are necessary in this study. scc is defined by its behavior when it is in the fresh state, and it is determined whether concrete meets certain requirements, while flowability is an essential property in qualifying concrete as scc or not. the slump flow, l-box, v-funnel, vfunnel at t5 minutes and sieve segregation test are all used for all mixes of this study. 4.1 slump flow and t50cm tests the slump flow test is the most widely used method for evaluating concrete consistency and filling ability in the laboratory and at construction sites and can indicate segregation resistance of scc to an experienced user. the flowing ability of fresh concrete is described by slump flow investigated with abrams cone. (table 5) shows the slump spread values and t500 for the produced mixes. 4.2 l-box test the l-box test measures the passing ability of self-compacting concrete. originally developed in japan for underwater concrete. (table 5) shows the value of bl (h2/h1) which represents the blocking ratio and the value of t400 represents the time of concrete to reach 400 mm flow. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 431 4.3 v-funnel test and v-funnel at t5 minutes tests the v-funnel is used to measure the filling ability (flowability) of scc and can also be used to evaluate the material segregation resistance. (table 5) shows the results of v-funnel test. these results are within the limits pointed out in the literature, no blocking or segregation behavior was observed in all mixes. 4.4 sieve segregation resistance test the sieve segregation test is used to assess the resistance of (scc) to segregation. table 5 shows the value of segregation resistance results test of (scc) mixes. 5. testing of hardened concrete 5.1 compressive strength the compressive strength test was accomplished according to (b.s.1881). this test was conducted on 150 mm cubes by using a hydraulic compression machine with a capacity of 2000 kn. the average of three cubes was adopted for each test. 5.2 splitting tensile strength the splitting tensile strength was determined according to the procedure outlined in (astmc496). cylindrical concrete specimens (100x200 mm) were used. each splitting tensile strength value was the average of two specimens. 6. results and discussion 6.1 compressive strength the compressive strength test results of the concrete specimens were tested at ages (28, 56 and 90 days), three cubes are tested at each age for compressive strength determination of self compacting concrete with various percentages of gypsum content in fine aggregate are shown in (table 6) and (figures 1 and 2) . it can be seen that for all mixes, there is an optimum so3 content at which the compressive strength is maximum, beyond which content the compressive strength has decreased. the present data indicates that the optimum so3 content for these mixes is about (0.5) % (by weight of sand) and it is equal to 3.99 % by weight of cement for mixes which contain limestone powder filler and it is equal to 4.01% by weight of cement for mixes which contain limestone powder filler and metakaolin. from the results of compressive strength shown in table 6, and figures 1 and 2 it can be noticed that: 1. when so3 in fine aggregate increases from (0.37 to 0.5) %, this leads to an increase in compressive strength of the concrete cubes in the range (5.9, 7, and 8.7) % for dl1 at ages (28, 56 and 90) days respectively. 2. when so3 in fine aggregate increases from (0.37 to 1) %, this leads to a decrease in compressive strength of the concrete cubes in the range (5.4, 6.8 and 7.7) % for dl2 at ages (28, 56 and 90) days respectively. 3. when so3 in fine aggregate increases from (0.37 to 1.5) %, this leads to a decrease in compressive strength of the concrete cubes in the range (8.2, 8.8 and 9.9) % for dl3 at ages (28, 56 and 90) days respectively. this was expected since several researchers as mention above had referred to the presence of optimum gypsum content. the increase in compressive strength of the concrete can be attributed to the ettringite formation which is produced by a chemical reaction between so3, c3a and water. it fills some of the voids inside the cement past and increases the strength. but more ettringite formation induces internal stresses and decreases the compressive strength. but more ettringite formation induces internal stresses and decreases the compressive strength. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 432 also, results showed that the use of 10% high reactivity metakaolin (hrm) in self compacting concrete was the best compared with other mixes that contain limestone powder (lsp) by improving compressive strength for all sulfates contents and for all ages as shown below : 1. when so3 in fine aggregate increases from (0.37 to 0.5) % this leads to an increase in compressive strength of the concrete cubes in the range (7.7, 8.6 and 10.1) % for dml1 at ages (28, 56 and 90) days respectively. 2. when so3 in fine aggregate increases from (0.37 to 1) %, this leads to a decrease in compressive strength of the concrete cubes in the range (1.4, 5.2 and 6.0) % for dml2 at ages (28, 56 and 90) days respectively. 3. when so3 in fine aggregate increases from (0.37 to 1.5) %, this leads to a decrease in compressive strength of the concrete cubes in the range (6.4, 7.4 and 8.2) % for dml3 at ages (28, 56 and 90) days respectively. the results indicated that the (scc) with(hrm+lsp) yielded the lowest compressive strength loss when compared (scc) with (lsp), this can be attributed to the fact of the incorporation of (hrm) in scc mix leads to minimized compressive strength loss compared to mixes without (hrm) this behaviour is due to the pozzolanic reaction of (hrm) which reacts with the calcium liberated during the hydration of cement and contributes to the densification of the concrete matrix resulting in a considerable increase in strength and reduction in permeability. besides, the pore-size and grain size refinement process associated with pozzolanic reaction can effectively reduce the microcracking and strengthen the transition zone [neville, a.m., -1995]. 6.2 splitting tensile strength results of the (28, 56 and 90 days) splitting tensile strength of concrete scc with various percentages of so3 content in sand are presented in (table 7) and (figures 3 and 4) for different mixes. it is clear that the effect of sulfates on the splitting tensile strength is somewhat similar to that on compressive strength. for all mixes, there is an optimum so3% content at which the splitting tensile strength is maximum, beyond this content the splitting tensile strength has decreased. from the results of splitting tensile strength shown in figures 3 and 4 it can be it can be noticed that: 1. when so3 in fine aggregate increases from (0.37 to 0.5) %, this leads to an increase in splitting tensile strength of the concrete cylinders in the range (1.2., 4.5 and 6.4) % for ml1 at ages (28, 56 and 90) days respectively. 2. when so3 in fine aggregate increases from (0.37 to 1) %, this leads to a decrease in splitting tensile strength of the concrete cylinders in the range (3.3, 3 and 2.7) % for ml2 at ages (28, 56 and 90) days respectively. 3. when so3 in fine aggregate increases from (0.37 to 1.5) %, this leads to a decrease in splitting tensile strength of the concrete cylinders in the range (5.6, 5 and 4.8) % for ml3 at ages (28, 56 and 90) days respectively. these results agree with that obtained by alwash and hussain. in addition also, results showed that the use of 10% high reactivity metakaolin (hrm) in self compacting concrete was the best compared with other mixes that contain limestone powder (lsp) by improving splitting tensile strength loss for all sulfates contents and for all ages as shown below : 1. when so3 in fine aggregate increases from (0.37 to 0.5) % this leads to an increase in splitting tensile strength of the concrete cylinders in the range (4.7, 6.2, and 8.5) % for dml1 at ages (28, 56 and 90) days respectively. 2. when so3 in fine aggregate increases from (0.37 to 1) %, this leads to a decrease in splitting tensile strength of the concrete cylinders in the range (2.4, 2.6 and 2.1) % for dml2 at ages (28, 56 and 90) days respectively. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 433 3. when so3 in fine aggregate increases from (0.37 to 1.5) % this leads to a increase in splitting tensile strength of the concrete cylinders in the range (4.5, 4.0 and 3.8) % for dml3 at ages (28, 56 and 90) days respectively. 7. conclusions based on the experimental of the present work, the following conclusions can be drawn: 1. with a constant superplasticizer dosage and water content, (scc) mixes with (lsp) had a better a filling ability, passing ability and segregation resistance than (scc) mixes with (hrm+lsp) in the fresh state. 2. there as optimum gypsum content at which the both compressive strength and splitting tensile strength are maximum, beyond which content the compressive strength and splitting tensile strength decrease. the optimum gypsum content for these mixes is about (0.5% by weight of fine aggregate) and it is equal to (3.99% by weight of cement) for mixes containing (lsp), while it is equal to (4.01% by weight of cement) for mixes containing (hrm+lsp). 3. the (scc) which contain 10% (hrm) as a partial replacement by weight of cement in mixes contain (hrm+lsp) was found to be effective in reducing compressive strength loss and splitting tensile strength loss due to interior sulfates contents in fine aggregate beyond optimum gypsum contact as compared with mixes contain (lsp). references alrawi r.s.,(1997), “gypsum content of cements used in concrete cured by accelerated methods", journal of testing and evaluation v.5, no.3, may, pp. 231-236. alrawi, r.s and abdul latif a. m., (1998) “ compatibility of sulphate contents in concrete ingredients", fourth scientific conference , college of engineering of baghdad university. al-kadhimi, t. k. and hamid, f. a., ( 1983) “ effect of gypsum present in sand on the properties of concrete", brc-journal, vol.2, no.2, , pp.17 41. al-qaisi, w.a., (1989) “the activity of sulfate contaminating fine aggregate in concrete", m.sc. thesis, university of baghdad, college of engineering. al-rawi, r.s., ali, n.h., shallal, a.r. and al-salihi, r.a., (1997) “effective sulfate content in concrete ingredients", 4th scientific and engineering conference, baghdad,pp.18-20. al-rawi, r.s., (2000) “some problems in concrete manufacture in the arab homeland and suggested remedial measures", arab conference of construction materials in egypt , pp.669-681. al-samerai m. , “limitation of sulfate in sand”, national center for construction laboratory, civilization journal, no. 1 , 1977, pp.38-52. alwash, j.j., (2005) “effect of sulfates in fine aggregate on drying shrinage cracking in end restrained concrete members" m.sc. thesis, university of babylon, college of engineering american society for testing and materials, astm c 494-05, “standard specification for chemical admixtures for concrete “annual book of astm standards, vol. 04-02, 2005. american society for testing and materials, astm c 618-05, (2005) standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete " annual book of astm standards, vol. 04-02 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 434 astm c496-86, (1989) “standard test method for splitting tensile of cylindrical concrete specimens", annual book of astm standard, vol. 04-02, 1989, pp.259-262. british standard institution,(1983) “method for determination of compressive strength of concrete cubes ", b.s.1881: part 116:, pp.3 . brooks, j.j. and johari, m.a.m., (2001) “ effect of metakaolin on creep and shrinkage of concrete " cement and concrete composites. vol.23, no.6, pp. 495 – 502. bs 7979, specification for limestone fines for use with portland cement. caldarone, m.a., gruber, k.a. and burg, r.g., (1994) “ high reactivity metakaolin (hrm): a new generation mineral admixture for high performance concrete " concrete international. vol. 16, no. 11, pp. 37 – 40. emborg m., ,(2000) “ mixing and transport ", brite euram, task 8.1. holschemacher, k., and klug, y.,(2002) “a database for the evaluation of hardened of scc”, lacer no. 7, 2002, pp.123-134. hussain, th, h., (2008) “ effect of sulfates in fine aggregate on some mechanical properties of self compacting concrete". m.sc. thesis, university of babylon, college of engineering iraqi organization of standards, ios 45/1984, for aggregate. iraqi organization of standards, ios 5/ 1984, for portland cement. moulin, e., blanc, p., and sorrentino, d., (2001) “ influence of key cement chemical parameters on the properties of metakaolin blended cements " cement and concrete composites, vol. 23, no. 6, pp. 463 – 469. neville, a.m., (1995), “properties of concrete'', five, and final edition, wiley, new york and longman, london, pp.844. okamura, h. and ouchi, m., (1999), “self-compacting concrete development, present and future”, proceedings of the first international rilem symposium on self-compacting concrete, pp.(314). sonebi , m. , grünewald , s., and walraven , j.(2007) , “filling ability and passing ability of self-consolidating concrete” , aci materials journal , v. 104, no. 2, march-april , pp.162-170. suksawang ,n., nassif, h., najm, s., (2006) “evaluation of mechanical properties for self consolidating, normal, and high-performance concrete(hpc)”, new jersey department of transportation (njdot) and the center for advanced infrastructure and transportation (cait) at rutgers, pp.3. wild, s., khatib, j. m., and jones, a., (1996) “ relative strength, pozzolanic activity and cement hydration in superplasticizer metakaolin concrete " cement and concrete research, vol. 26, no. 10, pp. 1537 – 1544. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 435 table 1: concrete mix designations mixes designation types of filler curing time (days) so3 content in sand (by weight of sand) % total so3 content (by weight of cement) % dl* 0 dl 1 dl 2 dl 3 limestone powder (lsp) 28, 56, 90 0.37 0.5 1.0 1.5 3.74 3.99 4.96 5.93 dlm *0 dlm 1 dlm 2 dlm 3 limestone powder plus high reactivity met kaolin (lsp+hrm) 28, 56, 90 0.37 0.5 1.0 1.5 3.76 4.01 4.98 5.96 dl*: mixes of scc with limestone powder filler (lsp). dlm* : mixes of scc with limestone powder filler (lsp) plus 10% high reactivity metakaolin (hrm). table 2: chemical analysis of the limestone powder (lsp) 0boxide content % 1boxide content % sio2 1.34 mgo 0.13 fe2o3 0.12 so3 1.90 al2o3 0.69 cao 55.13 table 3: chemical and physical properties of (hrm) oxides oxide content(%) burning temperature 700 c° requirements of class n pozzolan astm c 618-05 sio2 65.84 ≥ 70 al2o3 19.44 fe2o3 0.2 na2o 0.15 k2o 0.22 cao 5.92 mgo 0.88 so3 0.23 ≤ 4 l.o.i 4.43 ≤ 10 physical properties fineness (blaine method m2/kg) 700 specific gravity 2.5 materials content limitation (kg/m3) year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 436 proportions table 4 : mix table 5: results of fresh properties of ssc of all mixes test units mix notation typical range of values dl dlm slump-flow mm 740 680 600-800 t 50cm sec 3 3.5 2-5 v-funnel sec 6 7 6-12 v-funnel at t5 min. sec. 7 9 +3 sec , max. l-box (h2/h1) 1 0.9 0.8-1.0 sr % 3 2 ≤ 15% table 6: effect of sulfate content in fine aggregate on compressive strength of scc mix notation so3 content % by weight of fine aggregate total so3 content % by weight of cement compressive strength (mpa) for ages 28 (days) 56 (days) 90 (days) dl0 0.37 3.74 35.3 39.7 42.4 dl1 0.5 3.99 37.4 42.5 46.1 dl2 1.0 4.96 33.4 37 39.1 dl3 1.5 5.93 32.4 36.2 38.2 dlm0 0.37 3.76 44.0 50.1 54.5 dlm1 0.5 4.01 47.4 54.3 60.0 dlm2 1.0 4.98 43.4 47.5 51.2 dlm3 1.5 5.96 41.2 46.4 50.0 cement (kg/m3) 400 350-450 fine aggregate (kg/m3) 775 710-900 coarse aggregate (kg/m3) 820 750-920 filler (kg/m3) 100 50-150 (water / powder) ratio 0.42 0.33-0.62 sp (liter/100kg cement) 3 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 437 table7: effect of sulfate content in fine agg. on splitting tensile strength of scc mix notation so3 content % by weight of fine aggregate total so3 content % by weight of cement splitting tensile strength (mpa) for ages 28 (days) 56 (days) 90 (days) dl0 0.37 3.74 3.36 3.58 3.76 dl1 0.5 3.99 3.40 3.74 4.0 dl2 1.0 4.96 3.25 3.47 3.66 dl3 1.5 5.93 3.17 3.4 3.58 dlm0 0.37 3.76 4.21 4.52 4.70 dlm1 0.5 4.01 4.41 4.80 5.1 dlm2 1.0 4.98 4.11 4.4 4.6 dlm3 1.5 5.96 4.02 4.34 4.52 0.0 0.5 1.0 1.5 2.0 so3% in fine aggregate 30 35 40 45 50 co m pr es si ve s tre ng th (m pa ) ssc mixes with lsp 28 days 56 days 90 days 0.0 0.5 1.0 1.5 2.0 so3 % in fine aggregate 35 40 45 50 55 60 65 70 co m pr es si ve s tre ng th (m pa ) ssc mixes with lsp and hrm 28 days 56 days 90 days figure 1: relationship between compressive strength and so3 content in fine aggregate at different age with limestone powder filler. figure 2 : relationship between compressive strength and so3 content in fine aggregate at different age with limestone powder filler and metakaolin. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 438 0.0 0.5 1.0 1.5 2.0 so3% in fine aggregate 4.0 4.4 4.8 5.2 sp lit tin g te ns il st re ng th (m pa ) ssc mixes with lsp and hrm 28 days 56 days 90 days 0.0 0.5 1.0 1.5 2.0 so3 in fine aggregate % 2.8 3.2 3.6 4.0 4.4 sp lit tin g te ns ile s tre ng th (m pa ) ssc mixes with lsp 28 days 56 days 90 days figure 4 : relationship between splitting tensile strength and so3 content in fine aggregate at different age with limestone powder filler and metakaolin. figure 3: relationship between splitting tensile strength and so3 content in fine aggregate at different age with limestone powder filler. oxide oxide al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 108 advanced model for the effective moment of inertia taking into account shear deformations effect dr.haider k. ammash in civil engineering, university of al-qadisiya mr. muthana h. muhaisin in civil engineering, university of al-qadisiya abstract the study aims to present anew form of the effective moment of inertia by enhancement branson's model to take the effect of several factors such load type(concentrated, uniformly distribution, and two points) loads, shear deformations affect are also considered. these deformations depend on the span to depth ratio. the results of the presented model were compared with (experimental results, branson's model results, and results of other models). the results of the present model give best agreement with experimental results than branson's and the other models; the results showed that the effective moment of inertia reduced by about 27% for span to depth ratio of (20 to 5) due to shear deformation effects. keywords: beams, reinforced concrete, deflection, effective moment of inertia, shear deformation. ��ر ����� ا� � ه�ت ا������� ذج ��م ���م ا� �� ر ا�"ا�' ا�&��ل $�#" ! �� ا�� 8� �� 8 �� 9 :� 2� ا��2; =�> ا�3 � ا���د������ 2ر آ�?> ��1ش.د� 2� ا��2; =�> ا�3 ����� ا���د ا�*()� �ر ��ة ��ا ' =,�ف ا��را�y إ�� =�e �i�j d$�p$�ة � aم ا��4pر ا�&ا=� ا�) �ل r��5�/ ���ذج 5�ا��rن < ��cا �025 &g' ��ع ا���' )aآ� �زع �0���5م ، ، /��qp� � aآ� ( � rfو� z�rfا� �fء إ��gf(ا� � rf� ��� د����c�5 hpو=��ه�ت ا� u��rا�� �$��) u��rا�� �$�� iigfا� �fpq2 �f u��rا�� �$�� � r� ا��� ا�� �pq2 � .( lf [fر��j م�fpذج ا���f�2ا� km�f�� ) ����� km��� ، ى�f-ذج أ�f�� km�f�� ن و�rا��ذج 5��� km��� .( ذج�f�� /f �f��� ا� km�f�2�� ب�fjأ km�f�� �fq $ م�fpذج ا���f�2ا� � ، 5�ا��rن وا���2ذج أ-f�ى rf25 'fp$ ل�f (ا� �ا=&f�4ر ا�fpم ا�af� إن km�f�2ا� [f2�5 z�&fء % ٢٧آ�gf � rf2�\ /f z�rfا� .����� =��ه�ت ا�hp) ٥ا��20( al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 109 notations b1=top flange width. b2=bottom flange width. bw=web width. d = effective depth of tension region. d' = effective depth of compression region fr=modulus of rupture h=total depth of beam. ie : effective moment of inertia. icr : cracked moment of inertia. ig : gross moment of inertia. ma: applied external moment. mcr: cracking moment n=modular ratio. =ρ ratio of steel area at tension region. =ρ′ ratio of steel area at compression region introduction deflections of reinforced concrete flexural members were the focus of several research activities for many years. it is prime importance in the determination of the deflection of beams is calculation of the moment of inertia (i) of the beam, since its value changes along the span length from (ig) for uncracked sections to (icr) for cracked sections. branson developed a well known expression for the effective moment of inertia (ie) over the entire length of the simply supported beam in the following form: cr 3 a cr g 3 a cr e i m m 1i m m i ×               −+×      = (1) the aci building code adopted branson’s equation and it first appeared in the 1971 edition of the publication and remains the recommended way of calculating the effective moment of inertia for the purpose of calculating the deflection of a reinforced concrete member. since its adoption by the aci code in 1971, branson’s model has been continually opposed. the reasons vary, but center around the accuracy of the model. design engineers argue that the cumbersome calculation of icr, especially for flanged sections, is complex and time consuming (grossman 1981). they also argue that the effort required is not justified by the final product. grossman (1981) states that the estimated deflection obtained by using branson’s model is, at best, within ±20 % of experimental deflections obtained in a controlled lab setting. another argument against branson’s model is that its empirical nature can produce gross errors when applied to beams that are heavily or lightly reinforced and/or al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 110 subjected to non-uniform loads. researchers have shown, that in some instances, branson’s model can produce values that are 100% in error (fikry and thomas 1998). the arguments and concerns prompted various researchers to study the validity of branson’s equation. the subsequent research produced numerous simplifications and enhancements to the branson model. modifications to the ie method 1 method (1) in 1991 scholars from king saud university in riyadh, saudi arabia published findings from research they conducted to determine if non-uniform load configurations are accurately accounted for by branson’s effective moment of inertia model (al-zaid, al-shaikh, and abuhussein 1991). the research compared theoretical moment of inertia values to experimental moment of inertia values obtained from subjecting reinforced concrete members of rectangular cross-section to a uniform load, a mid-span concentrated load, a third-point load, and a mid-span concentrated load combined with a uniform load. the service load moment applied to the member was the same for each load configuration. it was observed that the experimental moment of inertia values for a member subjected to a mid-span concentrated load was 12% greater than that experienced by a member subjected to a third-point load and 20% greater than the experimental moment of inertia exhibited by a member subjected to a uniform load. the experimental values proved that branson’s model can not be accurate for all loading cases. equation (1) returns a value comparable to the experimental value for the uniform loading case, which means that if the member is loaded with a concentrated load at mid-span the stiffness of the member would be significantly underestimated. the researchers addressed the discrepancy by suggesting that branson’s model be generalized by modifying it to the form of equation (2). cr m a cr g m a cr e i m m 1i m m i ×               −+×      = (2) where: m : experimentally determined exponent. in their report the researchers showed that by generalizing equation (1) and in-turn solving for m (equation 3) for each load case that the discrepancy could be eliminated. m m log i-i i-i logm a cr crg crexp               = (3) where: iexp : experimental moment of inertia. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 111 2 method (2) the researchers argued that the discrepancy revealed in branson’s model was caused by the different lengths over which a beam cracks due to a specific load condition (al-zaid, et. al. 1991). therefore, the authors suggested a model (equation 4), similar in form to branson’s model, that incorporated the ratio of cracked length to overall length which inherently accounted for the variation in the effective moment of inertia caused by different cracked lengths (equation 4). g *m cr cr *m cr e i l l 1i l l i ×               −+×      = (4) where: m * : experimentally determined exponent. lcr : cracked length of the member. l = length of member the proposed model is bounded by ie = ig when lcr = 0, and ie = icr when the cracked length covers nearly the entire length of the member. the exponent m’ is calculated using equation (3). in theory, the exponent m * is solely a function of the reinforcement ratio. this theory was later expanded on by the same researchers (al-shaikh and al-zaid 1993). l l log i-i i-i logm cr crg expg*               = (5) where: iexp : experimental moment of inertia. the researchers exhibited that the “modified” form of branson’s model and the proposed model incorporating cracked length both produce effective moment of inertia values relatively close to experimental moment of inertia values when the proper exponent is employed. as a continuation of the aforementioned study, two of the authors later executed an experimental program to study the effect that reinforcement ratio (ρ) plays on a reinforced concrete member’s effective moment of inertia (al-shaikh and al-zaid 1993). the experimental program was conducted by applying a mid-span concentrated load to reinforced concrete beams, of rectangular cross-section, containing varying amounts of reinforcement. the test specimen labels and reinforcement quantities were: reinforcement label reinforcement ratio lightly 0.8 normally 1.4 heavily 2.0 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 112 the study revealed that branson’s model underestimated the effective moment of inertia of all test specimens. the underestimation of ie was approximately 30% in the case of a heavily reinforced member and 12 % for a lightly reinforced specimen. beyond the previously observed behavior of a reinforced concrete member subjected to a mid-span concentrated load (al-shaikh and al-zaid 1993), it is obvious that reinforcement ratio affects the accuracy of branson’s model especially when the member is heavily reinforced. therefore, by curve fitting, the authors derived an expression (equation 6) to calculate the exponent m for use in equation (3) which was introduced in the aforementioned study by the same authors. ρ×−= 8.00.3m (6) where: m = experimentally determined exponent ρ = reinforcement ratio. the authors also applied the more general equation (4), introduced in their earlier research, and to the values obtained from this experiment. the experimental values were used to develop equation (7) to determine the exponent m’ for equation (4) a cr* m m m ×= β (7) where: m * = experimentally determined exponent and β = 0.8 ρ where: ρ = reinforcement ratio the use of equation (4) may be better suited when considering the affects of reinforcement ratio on the effective moment of inertia, because the discrepancy created by load configuration is already taken into account by the cracked length term of the equation, which leaves the exponent m’ dependent only on the reinforcement ratio. 3 method (3) in 1998, a new model was proposed by fikry and thomas were derived an effective moment of inertia model from basic concrete flexural response theory. their focus was developing an effective moment of inertia model that eliminated the laborious icr calculation associated with branson’s model and more accurately accounted for variations in reinforcement ratio as well as load configuration. the derivation of the new model was based on an approximation for icr, which the authors called icre. the authors began their derivation with a cracked, singly reinforced, rectangular cross-section concrete member. they then derived icr as a function of two variables (η and ρ) and represented it in the form of equation (8), ( )         ×+= 12 bd i 3 cre βηρα (8) where, icre = approximate moment of inertia, α = constant (given in literature), β = constant (given in literature), η = modular ratio, ρ = reinforcement ratio, b = width of member, and d = effective depth of reinforcement, this derivation achieved their first goal al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 113 (((( )))) (((( )))) (((( )))) (((( )))) 2 f 2fw2 3 fw2 2 f gfw2 2 f 3 fw1 2 gw 3 w g 2 h yhbb 12 hbb 2 h yhbb 2 h -c 12 hbb y2 h hb 12 hb i 2 2 2 2 2 11         −−−−−−−−++++ −−−− ++++         −−−−−−−−++++        ++++ −−−− ++++      ++++==== (eliminating the icr calculation) and the approximation was within 6% of the cracked moment of inertia of all test specimens. the cracked moment of inertia approximation was then expanded to flanged cross-sections and doubly reinforced, rectangular and flanged crosssections. 4 proposed model the deflections caused not only by changes of curvature but also by changes of shear deformations those are not always negligible, especially in the case of beams with span/depth ratio(l/h< 10) and in the case of amore pronounced of shear forces. the proposed model for the effective moment of inertia takes into account several effects such as (1. type of loading, 2.(span/depth) ratio, 3. reinforcement ratio, 4. ratio of (compression/tension) reinforcement, 5. (effective depth/web width) ratio). the proposed model takes the following form: (9) where (10) the cross and cracked moment of inertia for beam with deferent cross sections as shown in figure below can be calculated as (11) )(i m m )(i m m i cr )( a cr g )( a cr e βξγξ γξγξ +××               −++×      = ++ ( ) )(iii l h n f i i b d 525.026.5 creg l cr g w βξ ξ η αρρ γ η ρ ρ β α +≤≤ = +′ −= = ′ =       −= al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 114 ( ) ( ) ( ) ( ) ( )3s 2 1s 2f fw1 3 fw1 3 w cr cdan dca1n) 2 h -(chbb 12 hbb 3 cb i 2 1 1 1 1 −×+ −−+−+ − += g2 y-hy , =         ++ = 0 10 2 11 a2 )a a4a(ac, 2 0 wba ==== (((( )))) 111 fwss hbbna1)a-(na 21 −−−−++++++++==== (((( )))) 2 212 fwss hbbdnad1)a-(na 21 −−−−++++++++==== (12) where, fl= factor depend on loading type such as: 1. distributed load =1.25 2. two point load =1.0 3. concentrated load =0.75 properties and abilities of the program the computer program (emircm)(effective moment of inertia for reinforced concrete members) is designed to deal with reinforced concrete members with many types of cross section with inclusion of transverse shear deformation effect and subjected to many types of loads. the computer program is coded in fortran 90 language executed by pc pentium iv 2800 mhz full cache intel processor compatible computer with 2.0 gb ram. the properties and abilities of this program may be summarized as follows: 1many types of loading such as (distributed loads, two point loads, and concentrated load). 2many types of cross section of members. 3using three different types of methods. numerical examples in order to verify the reliability of the adopted proposed method, some case studies reported by other researchers are utilized and compared with experimental and branson' model, and al-zaid et al. model. 1 comparison with experimental investigations of reinforced concrete members under concentrated loading at mid span areinforced concrete simply supported beam under concentrated loading (with l/h=12.5) the accuracy of the results of the present analysis of real panels is checked through comparing with the experimental and numerical results studied by al-zaid et al. [1991] on g gr cr y if m = al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 115 simply supported reinforced concrete members and with branson's model. the dimensions and material properties of the beams, as shown in figure (2). figure (3) shows a comparison with the experimental and the numerical results for the deflection at mid span. the results obtained from the present study give good agreement with the experimental results obtained by al-zaid, et al. [1991] with difference not more than (0.5%) with the experimental investigation while the difference between the branson's model with the experimental results more than (17%) and so the difference between al-zaid et al. model with the experimental results more than (20%) at ultimate load stage. the loaddeflection results are listed in table (1). breinforced concrete simply supported beam under concentrated loading (with l/h=٦.٥٣) one in a series of beams tested by (bresler and scordelis) was also examined the beam is simply supported and subjected to a concentrated load at mid span, the dimensions and material properties of the beams as shown in figure (4). in the present study, this beam is analyzed using the proposed method with factor for typing of loading (fl=0.75). figure (5) shows a comparison with the experimental and the numerical results for the deflection at mid span. the results obtained from the present study give good agreement with the experimental obtained by bresler and scordelis with difference about than (12%) with the experimental investigation while the difference between the branson's model with the experimental results more than (42%) and so the difference between al-zaid et al. model with the experimental results more than (47%) at ultimate load stage. the load-deflection results are listed in table (2). creinforced concrete simply supported beam under concentrated loading (with l/h=٦.٥5) one in a series of beams analyzed by kreshna was also examined the beam is simply supported and subjected to a concentrated load at mid span, the dimensions and material properties of the beams as shown in figure (6). figure (7) shows a comparison with the experimental and the numerical results for the deflection at mid span. the results obtained from the present study give good agreement with the experimental obtained by kreshna with difference not more than (12%) with the experimental investigation. this test shows the effect of area of steel at compression region on the behavior of reinforced concrete members. the load-deflection results are listed in table (3). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 116 dreinforced concrete simply supported beam under concentrated loading (with l/h=7.5) nurnbergerova et al. tested several reinforced concrete beams with i-cross section. the dimensions and materials properties of the beams as shown in figure (8) figure (9) shows a comparison with the experimental and the numerical results for the deflection at mid span. the results obtained from the present study give good agreement with the experimental obtained by nurnbergerova et al. with difference not more than (4%) with the experimental investigation while the difference between the branson's model with the experimental results more than (42%) and so the difference between al-zaid et al. model with the experimental results more than (44%) at ultimate load stage. the load-deflection results are listed in table(4). 2 comparison with experimental investigations of reinforced concrete members under distributed loading areinforced concrete simply supported beam under distributed loading (with l/h=12.5) the accuracy of the results of the present analysis of real panels is checked through comparing with the experimental and numerical results studied by al-zaid et al. [1991] on simply supported reinforced concrete members and with branson's model. the dimensions and material properties of the beams, as shown in figure (10). figure (11) shows a comparison with the experimental and the numerical results for the deflection at mid span. the results obtained from the present study give good agreement with the experimental obtained by al-zaid, et al. with difference not more than (8%) with the experimental investigation while the difference between the branson's model with the experimental results more than (15%) and so the difference between al-zaid et al. model with the experimental results more than (6%) at ultimate load stage. the load-deflection results are listed in table (5). 3 comparison with experimental investigations of reinforced concrete members under two point loading areinforced concrete simply supported beam under two point loading (with l/h=12.5) the accuracy of the results of the present analysis of real panels is checked through comparing with the experimental and numerical results studied by al-zaid et al. [1991] on simply supported reinforced concrete members and with branson's model. the dimensions and material properties of the beams, as shown in figure (12). figure (13) shows a comparison with the experimental and the numerical results for the deflection at mid span. the results obtained from the present study give good agreement with the experimental obtained by al-zaid, et al. with difference not more than (3%) with the experimental investigation while the difference between the branson's model with the experimental results more than (3%) and so the difference between al-zaid et al. model with al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 117 the experimental results more than (7%) at ultimate load stage. the load-deflection results are listed in table(6). 4 parametric study aeffect of tension reinforcement steel ratio of flexural on the effective moment of inertia a simply supported rectangular cross section beam subjected to concentrated loading at mid span was analyzed with a range of (ρρρρ) from (0.5-3.0%). figure (14) shows the effective moment of inertia ratio-applied moment ratio curve for the reinforced concrete member with a range of steel ratio (0.5-3.0%). the following properties of the beam are (h=200 m, b=200 mm, ec=29.634×10 6 kn/m 2 , l=2500 mm,fy=153 mpa, fc'=38.12 mpa). beffect of slenderness ratio on the effective moment of inertia a two simply supported reinforced concrete beams subjected to concentrated loading at mid span were analyzed with a range of slenderness ratio (l/h) (5-20). figure (15) and (16) show the effective moment of inertia ratio-applied moment ratio curve for the reinforced concrete member with a range of slenderness ratio (5-20). the following properties of the rectangular cross section beam are (h=200 m, b=200 mm, ec=29.634×10 6 kn/m 2 , l=2500 mm,fy=413 mpa, fc'=38.12 mpa) and the properties of beam with i-section were mentioned at figure(7). from these figures can be noticed that the effective moment of inertia is reduced by about 27% for the range of slenderness ratio (20-5) which can be attributed to shear deformations effect which increase with decreasing of slenderness ratio where this effect was neglected by the other models. deffect of compression tension reinforcement steel ratio on the effective moment of inertia a simply supported rectangular cross section beam subjected to concentrated loading at mid span was analyzed with a range of (as'/as) from (0.0-0.5%). figure (17) and (18) shows the effective moment of inertia ratio-applied moment ratio curve for the reinforced concrete member with a range of (as'/as) from (0.0-0.5%). the following properties of the beam are (h=200 m, b=200 mm, ec=29.634×10 6 kn/m 2 , l=2500 mm, fy=413 mpa, fc'=38.12 mpa). from these figures can be noticed that the effective moment of inertia is increased by about 21% for the range of ((as'/as)) (0.0-0.5) which can be attributed to compression reinforcement. the increase compression reinforcement lead to reduce the deformations of reinforced concrete members. where this effect was neglected by the other models. conclusions the research was presenting a new form of the effective moment of inertia by enhancement branson's model taking into account the effect of several factors such as type of loading, shear deformations, reinforcement ratio. the results of the presented model were compared al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 118 with (experimental results, branson's model results, and results of other models). the results of the present model give best agreement with experimental results than branson's and the other models. the following conclusions are drawn with regard to the results obtained for the present study such as: 1. the results showed that the effective moment of inertia reduced by about 27% for span to depth ratio of (20 to 5) due to shear deformation effects. 2. the present model gives good agreement with the experimental results for all types of cross section. references 1. aci committee 318 "building code requirement for reinforced concrete and commentary (aci 318-89 /aci 318r-89),american concrete institute ,detroit, 1989, 353 pp. 2. al-shaikh, a.h. and al-zaid, r.z., “effect of reinforcement ratio on the effective moment of inertia of reinforced concrete beams,” aci, struct. j.,vol. 90, no.2, march-april,1993, pp.144-148. 3. al-zaid, r. z. and al-shaikh, a.h. and abu-hussein, m., “effect of loading type on the effective moment of inertia of reinforced concrete beams,” aci, struct.j.,vol.88, no.2, march april 1991, pp.184-190. 4. branson,d.e., "instantaneous and time dependent deflection of simple and continoues reinforced concrete beams" hpr report no.7,part 1,albama,highway department /us bureau of public roads,1965,pp.1-78 5. fikry, a.m. and thomas, c., “development of a model for the effective moment of inertia of one-way reinforced concrete elements,” aci, struct. j.,vol.95,no.4, july-august 1998, pp.444-455. 6. grossman, j.s., “simplified computations for effective moment of inertia and minimum thickness to avoid deflection computations,” aci, struct. j., vol.78, no. 6,november-december 1981, pp. 423-434. 7. joseph e. wickline “a study of effective moment of inertia models for full-scale reinforced concrete t-beams subjected to a tandem-axle load configuration”, m.sc. thesis, dept. of civil and envir. eng. faculty of the virginia polytechnic institute and state university. 8. nurnbergerova, t., krizma, m., and hajek, j., “theoretical model of the determination of the deformation rates of r/c beams” j. const. and build. mat., vol.15, 2001, pp.169-176. 9. muhaisin, m. h. “nonlinear analysis of reinforced concrete plane frames under moving loads”, m.sc. thesis, dept. of civil eng., college of eng., university of babylon, (2003). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 119 deflection (mm) load (kn) experimental results branson method al-zaid,et al. method present study 0.0 0.00 0.00 0.00 0.00 50.6 0.60 0.49 0.49 0.51 101.2 1.40 1.59 1.24 1.41 149.5 2.25 2.55 2.04 2.48 200.1 3.20 3.48 2.90 3.78 250.7 4.20 4.40 3.76 5.23 299.0 5.50 5.26 4.60 6.73 349.6 7.20 6.17 5.49 8.41 400.2 9.20 7.06 6.37 10.20 450.8 12.40 7.96 7.26 12.07 460.0 14.20 8.13 7.42 12.41 deflection (mm) load (kn) experimental results branson method al-zaid,et al. method present study 0.00 0.00 0.00 0.00 0.00 9.88 1.05 1.44 1.00 1.03 11.82 1.50 2.17 1.35 1.39 13.76 1.95 2.915 1.71 1.80 15.70 2.50 3.64 2.10 2.24 17.65 3.05 4.34 2.51 2.73 19.59 3.63 5.02 2.94 3.24 21.53 4.23 5.67 3.38 3.79 23.47 4.77 6.31 3.82 4.37 25.59 5.40 6.98 4.32 5.04 27.71 6.13 7.65 4.83 5.74 31.77 7.31 8.90 5.84 7.17 35.30 8.47 9.97 6.73 8.51 table (1): load-deflection results of reinforced concrete simply supported beam under concentrated load at mid span table (2): load-deflection results of reinforced concrete simply supported beam under concentrated load at mid span al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 120 deflection (mm) load (kn) experimental results branson method al-zaid,et al. method present study 0.00 0.00 0.00 0.00 0.00 44.83 0.52 0.81 0.75 0.65 89.65 1.3 2.07 1.78 1.69 134.48 2.25 3.17 2.82 2.90 179.31 3.65 4.27 3.90 4.32 224.14 5.2 5.37 4.98 5.85 260.00 6.35 6.21 5.82 7.12 deflection (mm) load (kn) experimental results branson method al-zaid,et al. method present study 0.0 0.00 0.00 0 0 25.0 0.40 0.39 0.35 0.38 50.0 0.85 1.04 0.85 0.96 75.0 1.40 1.60 1.37 1.66 100.0 2.10 2.16 1.91 2.45 125.0 3.00 2.70 2.44 3.29 150.0 4.10 3.25 2.98 4.21 175.0 5.10 3.80 3.53 5.18 200.0 6.10 4.35 4.07 6.19 225.0 7.25 4.89 4.61 7.24 250.0 8.50 5.43 5.15 8.33 275.0 9.50 5.16 4.87 7.79 300.0 10.70 6.52 6.23 10.63 325.0 11.7 7.07 6.77 11.82 350.0 12.70 7.61 7.32 13.04 375.0 13.85 8.15 7.86 14.29 400.0 15.00 8.69 8.40 15.56 table (3): load-deflection results of reinforced concrete simply supported beam under concentrated load at mid span table (4): load-deflection results of reinforced concrete simply supported beam under concentrated load at mid span al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 121 deflection (mm) total load (kn) experimental results branson method al-zaid,et al. method present study 0.00 0.00 0.00 0.00 0.00 17.95 1.21 1.23 1.40 1.15 20.30 1.67 1.61 1.92 1.49 22.36 2.10 1.97 2.40 1.81 24.41 2.50 2.34 2.90 2.17 26.18 2.90 2.67 3.32 2.50 28.53 3.43 3.13 3.88 2.97 31.77 4.16 3.77 4.63 3.68 35.60 5.10 4.54 5.50 4.60 39.42 6.00 5.318 6.32 5.60 43.24 6.95 6.093 7.13 6.67 47.36 7.90 6.92 7.97 7.90 50.90 8.85 7.63 8.68 9.01 54.72 9.83 8.39 9.43 10.28 58.84 10.84 9.21 10.22 11.70 deflection (mm) total load (kn) experimental results branson method al-zaid,et al. method present study 0.00 0.00 0.00 0.00 0.00 11.73 0.91 0.95 0.89 0.88 14.21 1.48 1.62 1.39 1.28 15.79 1.87 2.10 1.74 1.55 18.04 2.45 2.81 2.27 2.00 19.85 2.91 3.38 2.73 2.39 21.65 3.43 3.96 3.20 2.80 25.48 4.51 5.14 4.21 3.79 29.54 5.55 6.32 5.31 4.96 33.38 6.63 7.39 6.35 6.18 37.21 7.68 8.42 7.37 7.50 41.27 8.89 9.49 8.46 9.00 45.11 10.18 10.48 9.47 10.50 table (5): load-deflection results of reinforced concrete simply supported beam under distributed load table (6): load-deflection results of reinforced concrete simply supported beam under two point loads al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 122 2φ16 1φ10 mpayf mparf gpace mpacf 413 393 63429 238 ==== ==== ==== ====′′′′ . . . l=2500 mm b=200 mm h=200 mm figure (2): details of a reinforced concrete simply supported beam under concentrated load at mid span with (l/h=12.5)(al-zaid, et al.) figure (3): load-deflection curve of reinforced concrete simply supported beam under concentrated load at mid span (al-zaid, et al.) 0 1 2 3 4 5 6 7 8 9 10 central deflectin 0 5 10 15 20 25 30 35 40 l o a d ( k n ) experimental work branson method al-zaid, et.al. method present method figure (1): details of uncracked and cracked cross section as2 as1 b1 b2 hf1 hf2 bw d d1 h (a) uncracked cross section nas (n-1)as1 b1 n.a (b) transformed cracked section al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 123 mpayf mparf gpace mpacf 345 043 03723 124 ==== ==== ==== ====′′′′ . . . l=3660 mm b=305 mm h=560 mm figure (4): details of a reinforced concrete simply supported beam under concentrated load at mid span with (l/h=6.53)( bresler and scordelis) 4φ28 2φ12 figure (5): load-deflection curve of reinforced concrete simply supported beam under concentrated load at mid span (bresler and scordelis) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 central deflection (mm) 0 50 100 150 200 250 300 350 400 450 500 l o a d ( k n ) experimental work branson method al-zaid, et.al. method present method mpayf mparf gpace mpacf 345 003 03723 124 ==== ==== ==== ====′′′′ . . . l=3657 mm b=225 mm h=558 mm figure (6): details of a reinforced concrete simply supported beam under concentrated load at mid span with (l/h=6.55)( kreshna) 4φ28 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 124 0 1 2 3 4 5 6 7 8 central deflection (mm) 0 50 100 150 200 250 300 l o a d ( k n ) experimental work branson method al-zaid et al method present method figure (7): load-deflection curve of reinforced concrete simply supported beam under concentrated load at mid span (kreshna) 3600 11φ16 2φ10 mpayf mparf gpace mpacf 345 262 8537 124 ==== ==== ==== ====′′′′ . . . l=3660 mm b=305 mm h=560 mm figure (8): details of a reinforced concrete simply supported beam under concentrated load at mid span with (l/h=7.5)( nurnbergerova et al.) figure (9): load-deflection curve of reinforced concrete simply supported beam under concentrated load at mid span (nurnbergerova, et al.) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 central deflection (mm) 0 50 100 150 200 250 300 350 400 l o a d ( k n ) experimetal work branson method al-zaid et al present method al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 125 mpayf mparf gpace mpacf 413 393 63429 238 ==== ==== ==== ====′′′′ . . . l=2500 mm b=200 mm h=200 mm figure (10): details of a reinforced concrete simply supported beam under distributed load with (l/h=12.5)(al-zaid, et al.) 2φ16 1φ10 0 1 2 3 4 5 6 7 8 9 10 11 12 central deflection (mm) 0 5 10 15 20 25 30 35 40 45 50 55 60 l o a d ( k n ) experimental work branson method al-zaid et al present method figure (11): load-deflection curve of reinforced concrete simply supported beam under distributed load (al-zaid et al.) mpayf mparf gpace mpacf 413 393 63429 238 ==== ==== ==== ====′′′′ . . . l=2500 mm b=200 mm h=200 mm 2φ16 1φ10 figure (12): details of a reinforced concrete simply supported beam under two point load with (l/h=12.5)(al-zaid, et al.) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 126 0 1 2 3 4 5 6 7 8 9 10 11 central deflection (mm) 0 5 10 15 20 25 30 35 40 45 50 l o a d ( k n ) experimental work branson method alzaid et al present method figure (13): load-deflection curve of reinforced concrete simply supported beam under two point load (al-zaid et al.) figure (14): effect of reinforcement steel ratio of flexural on the effective moment of inertia of simply supported concrete beam under concentrated load by present study 0 1 2 3 4 5 ma/mcr 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ie /i g ρ∗100 0.5 1.0 1.5 2.0 2.0 3.0 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 127 figure (15): effect of (span/depth) ratio of simply supported concrete beam under concentrated load (rectangular section) 0 1 2 3 4 5 6 ma/mcr 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ie /i g l/h 20.0 15.0 12.5 10.0 7.5 5.0 figure (16): effect of (span/depth) ratio of simply supported concrete beam under concentrated load (i-section) 0 2 4 6 8 10 12 14 16 18 20 ma/mcr 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ie /i g l/h 20.0 15.0 12.5 10.0 7.5 5.0 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 128 0 1 2 3 4 5 ma/mcr 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ie /i g as'/as 0.0 0.1 0.2 0.3 0.4 0.5 figure (18): effect of compression reinforcement steel ratio on the effective moment of inertia of simply supported concrete beam under concentrated load by present study 0 1 2 3 4 5 ma/mcr 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ie /i g as'/as 0.0 0.1 0.2 0.3 0.4 0.5 figure (1٧): effect of compression reinforcement steel ratio on the effective moment of inertia of simply supported concrete beam under concentrated load by branson method al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 59 study and analysis for the effects of power factor correction in al-najaf cement plant m.sc. haider muhamed umran university of karbala college of engineering electrical and electronic engineering department hyderumran@yahoo.com received 27 october 2014 accepted 24 december 2014 abstract the quality of an electrical power plays an important factor in any industrial process, these factors relate to the economic and technical benefits. the cement industry used many of the miscellaneous equipment's, which are classifying as non-linear loads such as induction motors, transformers and etc. the electrical equipment's are absorbing additional currents called "inductive reactive currents"; the effects of additional currents making electrical network inefficient, result of reducing the power factor. however, the low power factor will affect the increase the loads on the power station on the one hand and on the efficiency of the equipment's, capacity of transformer's, sizes of cables and capacity of switchgears on the other hand this in relation to the cement plant. in this paper, the effects of low power factor on main motors which use in al-najaf cement plant analyzed, such as raw material mill, cement mill and the clinker cooler. the necessary reactive power for the capacitor bank calculated according to practical readings for equipment's information that printed on the name-plates, by using two methods for calculation (the mathematical equations and table of factor k). the influence of power factor correction on the motors, transformers and sizes and losses of electrical cables calculated. the advantages of power factor correction are analyzed for economic and technical sides. keywords: reactive power, cement plant, maine equipment’s, power factor correction, motors. دراسة وتحليل تأثيرات تصحيح عامل القدرة في معمل سمنت النجف. حيدر محمد عمران كلية الهندسة /جامعة كربالء قسم الهندسة الكهربائية و االلكترونية الخالصة: تستخدم قنية.هذه العوامل بالمنافع االقتصادية و التتتعلق ،الكهربائية عوامل مهمة في أّي عملية صناعيةتلعب نوعية الطاقة تعمل الخ. ..و المحوالت الحثيةمثل المحّركات التي تصنف كأحمال غير خطية و المختلفةمعدات العديد من سمنتلا صناعة هوالتيارات االضافية ان تأثيرات هذه ، التيارات الحثية غير الفعالة" ى "تدعالمعدات الكهربائية على امتصاص تيارات اضافية ةدازييؤثر على ان معامل القدرة المنخفض س ،. على أي حالمعامل القدرةنخفاض ال نتيجةشبكة كهربائية غير كفوءة جعل ال قواطع سعات و القابلوات حجوملمحوالت و اسعة على الكهربائية من ناحية وعلى كفاءة األجهزة و طاقةل على محطة الاالحم تأثيرات انخفاض معامل القدرة على تحليل تم. في هذا البحث، سمنتالمعمل فيما يتعلق بهذا خرى ن ناحية االدورة الكهربائية م محّرك وطاحونة السمنت محّركحونة المواد االولية و اطمعمل سمنت النجف مثل محّرك مستخدمة فيال المحركات الرئيسيةا للمعلومات المطبوعة قراءات العمليةال ة لمصرف المكثّفات اعتماداً علىلقد تم احتساب القدرة غير الفعالة الضروري مبردة الكلنكر. القدرة معامل تصحيح تأثير سابتحا(. تم kالعاملجدول خداموإست الرياضية ين )المعادالتتعلى لوحات التسمية لألجهزة بطريق االقتصادية ومن الناحية فوائد تصحيح معامل القدرة تم تحليل . لكهربائيةالقابوات اخسائر و حجوم و المحوالت و المحركات على . التقنية mailto:hyderumran@yahoo.com al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 60 nomenclature: ir: active component of current. s1, s2: apparent power before and after power factor correction. p1, p2: active power before and after power factor correction. q c (actual): actual reactive power. c: capacitor. esp: electrostatic precipitator. p1losess, p2 losses: power losses before and after power factor correction. p.f.: power factor. iq: reactive component of current. qc: reactive power. q1, q2: reactive power before and after power factor correction. qc total: total reactive power. θ: displacement angle. η%: efficiency of motor. ∆p losses: reduction in power losses. 1. introduction in recent years, increasing attention has been paid to minimize the cost of energy and inefficiency in electricity generation, transmission and distribution especially in industrial applications. the machineries and equipment which using in cement industry are electrical motors, pumps, compressor, transformers, fans, blowers, conveyors, kilns, transportation, lightings and others. these machines consume different forms of energy according to the cement manufacture processes. the electrical power received from the high voltage or medium voltage grid has to be distributed to the medium and low voltage loads. this power has to be transformed to the medium voltage level for supplying a large drives; and then by distribution transformers to the low voltage level for smaller drives. the large numbers of electric drives makes the operation of these drives and their power consumption a significant cost factor. the active and reactive power consumption and harmonics influence on operating costs and efficiency of drive systems, transformer and the cable losses. therefore, the power factor and harmonics play major role, in improving of the machineries and equipment performance and reduce the cost of power consumption. in all electrical equipment the active power only be useful, whereas the reactive power does not make any useful contribution but it causes additional voltage drops and power losses which appear in the form of heat [5]. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 61 there are many researches have been done in the power factor improvement in cement factory. however, jbv, et al. [6] proposed thyristor switched capacitor to improve power factor in windmill power plant and used matlab software tool to obtain on results. ahrens, et al. [8] designed of harmonic filter and power factor compensation installations by several approaches in cement plants. gonzalez, et al. [3] designed the shunt filters to minimizing voltage distortion caused by nonlinear loads in industrial power systems. jain, et al. [5] use the switches bank to correct the power factor through generating the locally necessary reactive energy for the transfer of electrical useful power. nikolic, et al. [2] designed and implemented of measuring and information system for analysis of power quality in compliance with en 50160 in different points of power supply network. osafehinti, et al. [16] highlighted the methods of power factor correction in improving electricity supply and generated a table to determine a multiplying factor for all range of the power factor correction in the industrial environment. khalid, et al. [12] presented the power quality problems, issues, related international standard, and effect of power quality problem in different apparatuses in industry and methods for its correction. onohaebi, et al. [15] studied the power factor correction in improving the efficiency of energy consumption in industries using a medium scale industry in nigeria as a case study and an overview for power factor correction method and collection of various data relevant. in this paper, the electrical energy flow, effect of harmonics and the main parts of the for al-najaf cement plant are illustrated. the calculations of reactive power is focusing on the big from electrical motors, transformers, electrical cables and power losses in these cables, because they most effective on the power factor. these calculations are based on the practical readings for the equipment's. the controller on the power factor correction discussed and the necessary reactive power is calculated. 2. electrical energy flow and main equipments for factory the process of operation of al-najef cement plant is called wet process. the main equipment's of cement plant are classified according to the production stages. therefore, the electrical energy flow in a process of cement production as shown in fig.1. the electrical energy is not uniform and in some situations require to convert from ac to dc according to the equipment's use in process of cement production. the rated powers of the main equipment's for the factory set out in the table 1. the electrical power supplies to the factory through one feeder line to the distribution main station by 33 kv. the main power station consists of power transformer with 5 mva rated power 33/11kv and three main switch with rated 11kv 630a. the electrical substation includes a number of stepdown transformers to supply the loads by 3.3kv and 400v. in this research, the calculations were achieved only on the main equipment's, such as: motors of the raw mill, the cement mill, the cooler and on some transformer's. because they much effective in draw of reactive power if compared with other equipment's. 3. harmonics most the loads which are used in cement factory have resistive and reactive impedances therefore they called by non-linear loads and absorb non-sinusoidal current. these currents will increase the load on the electrical station switchgears and distribution network on the one hand and on the consumer's equipment's on the other hand. therefore they are causing in voltage drop of nonsinusoidal type from the supply side of electrical network. in consequence the linear loads will supply by distorted voltage [8], the fundamental and harmonics waveforms are shown in fig. 2. according to the fourier theorem, an ideal sinusoidal waveform does not present any harmonics for different order from the fundamental wave. therefore the presence of harmonics in electrical system is an indication of distortion of voltage or current waveform and this increases the value of al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 62 total harmonic distortion thd, and may cause disabling equipment's [17], the effects of harmonics on the equipment’s are summarized in table 2. 4. power factor the main effective equipment's which using in cement factories are inductive loads. furthermore in an ac electrical power system the value of total power (the apparent power) which drawn from the electrical station depends on the nature of the connected loads. the apparent power (currents which absorbed by loads) can analyze to two components: the active component (ir), which be in phase with the supply voltage, is directly related to the output the part of electric energy converted into different types from energy such as mechanical energy, light energy, thermal energy…etc.; and the reactive component (iq), in quadrature to the voltage, is used to generate the flow necessary for the conversion of powers through the magnetic fields to produce flux necessary for the operation of induction machines and other. in this case of loads the total current (i) lags with respect to the active component (ir). anyway define of a power factor cos θ, as the ratio between the active component (ir) and the total value of the current (i) as in eq. 1, [1]. the phase angle θ is the angle between the voltage and the current or between the apparent power (s) and active power (p) which are shown in fig. 3. in cement factory, the range of power factor is between of 0.7 to 0.8. this means that a 1mva transformer can only supply 700 – 800 kw or the loads can draw only 70 80 useful amps from a 100amp supply. so, improving the power factor means supplying the necessary reactive power to getting on active power or reduce the amount of wasted power (reactive power). 5. reactive power controller the power factor compensation system is essential to its application in electrical systems, according to the used machines work cycle which have different electrical characteristics. capacitor banks are used much to get the corrected power factor. these capacitor banks are operate and controlling it by automatic control relay. the relay maintain the system of power factor at a set value under fluctuating load conditions, by connecting or disconnecting capacitor banks to the 415v bus. the automatic compensation system is formed from some of detection sensors to detecting the current and voltage signals. the micro-controller comparing the measured power factor with the desired value and then, connecting and disconnect the capacitor banks. the electric board contains switches, protection devices and alarm signals. the circuit diagram of the relay as illustrated in fig. 4. [7]. 6. calculation of reactive power in this paper, calculations of the required capacitor to improve the power factor are achieved on the main equipment's. there are two methods to calculate the necessary capacitor bank to obtain a defined power factor by using mathematical analysis and table of coefficient k (kvar/kw) [4, 10]. 6.1. calculations of reactive power for motor of raw mill the type of raw mill drive is slip ring with the following specifications according to name plate: (50hz) line frequency, (3300v) three phase voltage, (970kw) rated power, (0.84) power factor and (212.5a) rated current. the power factor will improve up to (0.94) and will watching the effect of al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 63 this improving on the motor efficiency. the calculation of the reactive power as first step as in the following: where, the reactive power per phase is calculate as in eq. 3: ⁄ in a 3-phase system, the capacitor bank consisted by three capacitors having the same capacitance value and can be connected delta or star as shown in fig. 5. in this case, the capacitor bank connected in delta mode, to get a small size of the capacitances of each phase [13]. therefore, the total value of reactive power is calculated as in eq. 4. the value of the capacitor can be calculated according to the accurate value for reactive power. the practical efficiency of the motor calculates depending on the ratio between actual current (i1) to rated current (in name-plate) for motor as in eq. 5: √ now, the accurate (actual) value for reactive power is: ⁄ the value of capacitor is calculating as in eq. 8: √ the calculating the value of current which had drawn from the motor of the same rated power after factor improvement as: √ the saving in current about (21.46 a) and the apparent power reduce as shown in eq. (10 & 11). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 64 the reactive power reduces as shown in eq. (12 & 13). active power is calculating before and after power factor improving as: the apparent and reactive power reduced, while the value of active power still constant. however, the saving in current is (21.6a). the connection diagram for the power factor correction with the motors is shown in fig. 6. 6.2. the raw material mill feeding cable size calculations the benefits of improving power factor are not only limited in improving of the motor performance and the exploitation of active power fully, but also it exceeding to optimal use of the electrical lines [1]. the feeding cable to the raw mill is calculated according to the rated power of the load (motor). where, the effect of improving of power factor on current carrying capacity for cable is clarified through the calculations below. if is take into account the impact of starting current and effects of other factors on cable capacity, the cable is designed for carrying current the limits of (344.4a) with (0.84) power factor. under standard conditions, the cross sectional area for xlpe/epr cable which chosen is (120 mm 2 ), depending on the current carrying capacity (i) of copper cables as in table 3. now, the new value of current with (p.f = 0.94) and for the same consideration's, is (307.8 a). with this value of current, the cross sectional area becomes (95 mm 2 ). 6.3. the raw material mill feeding cable losses calculations the effect of improving power factor on the losses, with the same value of transmitted active power calculated. where, the power losses of an electric cable are depending on the resistance of the conductor and on the square of the current [9]. in this case, the length of cable used is (240m), the cross sectional area (120mm 2 ) with (0.84) power factor, therefore the resistance of the cable is (0.0204ω). in a three-phase system the losses are calculated as follows: now, the reduction in the losses after power factor correction is calculated as in eq. 18: where, (p losses1 and i1) are respectively the power losses and current before the power factor improving, (p losses2 and i2) are respectively the power losses and current after the power factor improving and (∆p losses) the reduction in the power losses. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 65 6.4. calculations of electrical transformer for raw material mill the size of the transformer specifies according to the apparent power (s). by improving the power factor, the value of reactive power (q) and the apparent power (s) would be reduced but still deliver the same active power (p) [7]. the variation of the power for mv/lv of three-phase transformers as a function of the p.f is defined by the table 4. however, the rated power of the transformer which feed raw mill 1500 kva and the necessary compensation power is (40.5 kvar). the transformer will supply 1050 kw as a total power to the load with (p.f. = 0.7). if the loads absorbed the same power with (p.f = 0.9), it would be sufficient to use a transformer with power (1250 kva). the necessary reactive power to correct the power factor for (0.94) is calculated as: when taking the necessary reactive power to operate the transformer in account, the total reactive power which delivers from the power factor correction unit becomes: 7. calculations of reactive power for cement mill the type of cement mill drive is slip ring with the following specifications according to name plate of motor: (50 hz) line frequency, (3300 v) three phase voltage, (1900 kw) rated power, (0.84) power factor and (422 a) rated current. the method of calculations in this section will depend on using table of coefficient k (kvar/kw) to extract the value of required reactive power per/phase as shown in the table 5. the power factor of motor is 0.84 and the power factor to be obtained is 0.94. the power of the capacitor bank qc is: the value of k is extracted from intersect the row " initial cos θ1" 0.84 with the column "final cos θ2" 0.94, that equals 0.283. so, where, referring to eq. (5-15) the results of calculations are illustrated in the table 6. 7.1. the cement mill feeding cable size calculations as illustrated in (6.2), the impact of starting current on cable capacity taken into account. therefore, the cable is designed for carrying current the limits of (674.7a) with (0.84) power factor. referring to table 3, the cross sectional area for cable chosen is (300 mm 2 ). the current with (0.94) power factor become (602.8a), according to table 3; the cross-sectional area for the cable becomes (240mm 2 ), with increasing a safety factor. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 66 7.2. the cement mill feeding cable losses calculations the length of cable used is (180m), the cross sectional area (300mm 2 ) with (0.84) power factor, therefore the resistance of the cable is (0.0252ω). referring to eq. (16-18), the results of power losses and reduction in the power losses are illustrated in table 7. 7.3. calculations of electrical transformer for cement mill the rated power of the transformer which feed cement mill (2000kva) and the necessary compensation power is 54kvar, the transformer will supplying (1200kw) as a total power to the load with (p.f.= 0.6). according to the table 2, if the loads absorbed the same power with (p.f. = 0.9), it would be sufficient to use a transformer with power (1500kva). the results of calculations for necessary reactive power to correct the power factor for (0.94) as it illustrated in (6.3) are: qc is 1163.23 kvar and qc total is 1217.23 kvar. 8. calculations of reactive power for motor of cooler the specifications of motor which use in the cooler according to name plate are: induction motor, (50 hz) line frequency, (200kw) rated power, (380v) three phase voltage with (0.84) power factor and (355a) rated current. the calculations of necessary actual value for reactive power to correct the power factor to (0.94), are achieved as illustrated in (6.1). the results of calculations for necessary actual reactive power capacitor, the current (before and after) power factor improvement and the other values are illustrated in table 8. 8.1. the cooler feeding cable losses calculations the actual length of cable used is (60 m). according to the rated current of motor, the crosssectional area for cable is (120mm 2 ); therefore the resistance of the cable becomes (0.0084ω). where, the calculations achieved according to eq. (16-18). the results of cable losses calculations are illustrated in table 9. 9. conclusion in this research, the effects of power factor on performance of the main motors, the electrical cables and transformers which are used in an alnajaf cement plant are discussed. the calculations of reactive power for power factor correction has demonstrated several benefits such as: the total value of current which is drawn from the network is reduced with limits of (96.23a) to the equipment’s which has been calculated, reduce the power rating of transformers, the reduction in the cross-sectional area of cables and decrease the losses of cables which is about (8.682 kw). the technical benefits of power factor correction are increasing the operational life for equipment's which are host in the factory and utilizing the complete active power. regarding the economic benefits of analyzing the mentioned equipment’s are the reduction of the cross sectional area of the used cables and the rated capacity of transformers and switchgears, this will have a great impact in cost reduction of these equipment's. references: [1] a. baggini, “handbook of power quality”, john wiley & sons ltd., 4 th edition, isbn 978-0470-06561-7, uk, sep., 2008. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 67 [2] a. nikolic, d. naumovic -vukovic, s. skundric, d. kovacevic, “methods for power quality analysis according to en 50160”, ieee, 9th international conference electrical power quality and utilization epqu, vol. 10, no. 9, p. 1-6, barcelona, spain, oct. 2007. [3] d. gonzales, a. damian, j. mccall, “design of harmonic filters to reduce harmonic distortion in industrial power systems” ieee trans, on industry app., vol. ia-23, no. 3, p. 504 – 511, issue 3, may, 1987. [4] eaton electrical inc., “power factor correction: a guide for the plant engineer”, manual, sa02607001e, usa, 2004. [5] j. sandesh, thakur shivendra s., phulambrikar s.p. “improve power factor and reduce the harmonics distortion of the system”, research journal of engineering sciences, vol. 1, no. 5, p.31-36, issn 2278 – 9472, nov. 2012. [6] j. subrahmanyam, s. radha k. r., p. k. sahoo, c. sashidhar, n. madhukar reddy, “a novel method for improvement of power factor using thyristor switched capacitor in windmill power station” international journal of emerging technology and advanced engineering, vol. 2, , p. 7175, issue 2. issn 2250-2459, feb. 2012. [7] k. ravi kumar, “impact of apfc panel at lt side of transformer” bhogadi. havya int. journal of engineering research and applications, vol. 4, issue7. (version 1), p. 49-54, july 2014. [8] m. ahrens, z. konstantinovic, “harmonic filters and power factor compensation for cement plants” ieee cement industry technical conference, vol. 10, no. 1, p. 77 103, 2005. [9] m. oke & o.m. bamigbola, “minimization of losses on electric power transmission lines”, mathematical theory and modeling, vol.3, no.7, p. 28-31, issn 2224-5804, 2013. [10] m. thein , e. ei cho, “improvement of power factor for industrial plant with automatic capacitor bank”, proceedings of world academy of science, engineering and technology, vol. 32, p. 695 -701, issn 2070-3740, aug. 2008. [11] r. keith mobley, “plant engineers handbook”, butterworth-heinemann, 3 rd edition, uk, isbn 0 7506 7328 11, 2001. [12] s. khalid, b. dwivedi, “power quality issuer, problems, standards & their effects in industry with corrective means”, international journal of advances in engineering and technology, vol. 1, issue 2, p. 1-11, issn: 2231-1963, may 2011. [13] s. khanchi, v. kumar, “power factor improvement of induction motor by using capacitors”, international journal of engineering trends and technology (ijett), vol.4, issue 7, p. 2967 – 2971, issn: 2967 – 2971, july 2013. [14] s. neelima, p. subramanyam, “differential evolution based optimization approach for power factor correction” aceee int. j. on electrical and power engineering, vol. 4, no. 3, p. 4954, nov. 2013. [15] s. onohaebi., odiase, o. f., osafehinti, s. i., “improving the efficiency of electrical equipment by power factor correction – a case study on medium scale study in nigeria” journal of mathematics and technology. vo.1, no. 2, p. 63, issue 2, april 2010. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 68 [16] s. osafehinti, o. arobieke, s. amodu , m. olusolade , “generating a multiplying factor to determine capacitor value for all range of power factor correction in industrial environment” proceedings of the world congress on engineering, london, u.k, vol. ii, p. 1088-1092, issn: 2078-0958, july 2013. [17] y. kusuma llatha, ch. sai babu, y. obulesu, “harmonics mitigation of industrial motor drives with active power filters in cement plant-a case study” , international journal of power electronics and drive system (ijpeds), vol. 2, no.1, p. 1-8, issn: 2088-8694, mar. 2012. table 1: the rated powers of the main equipment's. the unit in factory rated power (kw) type of machine crusher 2×130 induction motor raw material mill 975 slip ring motor kiln 410 dc motor cooler 200 induction motor cement mill 1900 slip ring motor table 2: the harmonics effect of on equipment’s. equipment’s effect of harmonics current losses overheat motor increased 1. the iron losses increase. 2. copper losses increase. excessive heat in motor windings cable increased 1. skin effect increased. 2. copper losses increase. overheating due to: 1. high load current. 2. conductor resistance increase. transformer increased increasing the iron and copper losses due to, stray flux losses. excessive heat in transformer windings. switchgears causing false operations and trips, damaging components for no apparent reason. capacitor bank the capacitors absorb higher current. increasing the losses excessive heat and the damage in final. table 3: current carrying capacity (i) of copper cables [11]. cu xlpe/epr pvc conductor cross-sectional area (mm 2 ) i (a) 35 176 143 50 216 174 70 279 225 95 342 275 120 400 321 150 464 372 185 533 427 240 634 507 300 736 587 400 868 689 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 69 table 4: power of three-phase transformers as a function of the p.f [7]. power of the transformer (kva) power of the transformer (kw) cos θ 0.5 0.6 0.7 0.8 0.9 1 125 63 75 88 100 113 125 160 80 96 112 128 144 160 200 100 120 140 160 180 200 250 125 150 175 200 225 250 315 158 189 221 252 284 315 400 200 240 280 320 360 400 630 315 378 441 504 567 630 800 400 480 560 640 720 800 1000 500 600 700 800 900 1000 1250 625 750 875 1000 1125 1250 1500 750 900 1050 1200 1350 1500 2000 1000 1200 1400 1600 1800 2000 table 5: factor k (kvar/kw) [4]. final p.f initial p.f 0.8 0.85 0.9 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1 0.74 0.159 0.289 0.425 0.453 0.483 0.514 0.546 0.580 0.617 0.658 0.706 0.766 0.909 0.75 0.132 0.262 0.398 0.426 0.456 0.487 0.519 0.553 0.590 0.631 0.679 0.739 0.882 0.76 0.105 0.235 0.371 0.400 0.429 0.460 0.492 0.526 0.563 0.605 0.652 0.713 0.855 0.77 0.079 0.209 0.344 0.373 0.403 0.433 0.466 0.500 0.537 0.678 0.626 0.686 0.829 0.78 0.052 0.183 0.318 0.347 0.376 0.407 0.439 0.474 0.511 0.552 0.599 0.660 0.802 0.79 0.026 0.156 0.292 0.320 0.350 0.381 0.413 0.447 0.484 0.525 0.573 0.634 0.776 0.8 0.130 0.266 0.294 0.324 0.355 0.387 0.421 0.458 0.499 0.547 0.608 0.750 0.81 0.104 0.240 0.268 0.298 0.329 0.361 0.395 0.432 0.473 0.521 0.581 0.724 0.82 0.078 0.214 0.242 0.272 0.303 0.335 0.369 0.406 0.447 0.495 0.556 0.698 0.83 0.052 0.188 0.216 0.246 0.277 0.309 0.343 0.380 0.421 0.469 0.530 0.672 0.84 0.026 0.162 0.190 0.220 0.251 0.283 0.317 0.354 0.395 0.443 0.503 0.646 0.85 0.135 0.164 0.194 0.225 0.257 0.291 0.328 0.369 0.417 0.477 0.620 0.86 0.109 0.138 0.167 0.198 0.230 0.265 0.302 0.343 0.390 0.451 0.593 0.87 0.082 0.111 0.141 0.172 0.204 0.238 0.275 0.316 0.364 0.424 0.567 0.88 0.055 0.084 0.114 0.145 0.177 0.211 0.248 0.289 0.337 0.397 0.540 0.89 0.028 0.057 0.086 0.117 0.149 0.184 0.221 0.262 0.309 0.370 0.512 0.9 0.029 0.058 0.089 0.121 0.156 0.193 0.234 0.281 0.342 0.484 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 70 table 6: calculation results of necessary reactive power for cement mill. comments q actual (kvar/phase) 191.2 i1 (a) 395.7 saving current is (42.13a) i2 (a) 353.6 c (μf) 16.77 η% 93.7 s1 (kva) 1306 s2 (kva) 1166.88 q1 (kvar) 708.6 44% reduction in reactive power q2 (kvar) 399.1 p1 (kw) 1097.04 the active power approximately equal p1 (kw) 1096.87 table 7: the calculation results of cable power losses for cement mill. p 1(losses 1) (kw) p 2(losses 2) (kw) ∆p loess (kw) 34.41 27.47 6.93 table 8: the calculation results for motor of cooler. comments qc (kvar/phase) 17.05 qc total (kvar) 51.2 i1 (a) 339.6 saving current is (32.5a) i2 (a) 307.1 η% 95.7 qc actual (kvar/phase) 17.82 c (μf) 10.64 s1 (kva) 135.84 9.56% reduction in apparent power s2 (kva) 122.84 q1 (kvar) 71.56 41.3% reduction in reactive power q2 (kvar) 42.01 p1 (kw) 114.11 the active power approximately equal p2 (kw) 115.46 table 9: the calculation results of cable power losses for cooler. p 1(losses 1) (kw) p 2(losses 2) (kw) ∆p loess (kw) 3 2.38 0.29 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 71 figure 1: electrical energy flow in processes of cement production. figure 2: fundamental waveform and a number of harmonics waveforms. figure 3: power factor triangle. crushing transport raw material mill kiln clinker cooling cement mill packing & dispatch electrical energy for crushers electrical energy for belt conveyors electrical energy for mill drive & fans electrical energy for kiln drive, fans & esp electrical energy for drive & fans electrical energy for drive buckets chain electrical energy for drive & fans electrical energy for machine & transports sets v t fundamental (50hz) third harmonic (150hz) fourth harmonic (250hz) resulting waveform θ ir iq i v θ p q s al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 72 figure 4: circuit diagram of the reactive power relay. figure 5: three phase circuit star and delta connection. figure 6: connection diagram of power factor correction with the motor. c 𝐕 √𝟑 v c v starte r r s t c m al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 911 a video concealed communication based on steganography using biorthogonal decimated wavelet transform and spiht codec asst. lecture: ahmed toman thahab university of karbala/ college of engineering/ electrical &electronic department toeahmed@gmail.com received 27 october 2014 accepted 3 february 2015 abstract steganography is the capability to embed important data in a cover media without alarming the observer that data is embedded. there are many methods which are used to carry secret data, mostly are image and audio. in this paper a new video steganography concealing a secret video in a cover video taking the technique of steganography to a new stage. the secret video is encoded using set partitioning in hierarchical trees (spiht) using bi-orthogonal decimated wavelet transform, the data of the secret video is embedded in the decimated wavelet domain of the cover media, in the three bands that have high frequency content, by replacing the cover coefficients of the wavelet domain with the encoded secret coefficients. the process is applied on each frame of the secret and cover videos producing an imperceptible and robust stego-video. image quality metrics are utilized to assess the performance of the algorithm. experimental results show that the method produces a high video resolution using various standard video sequences and other statistical assessment. proposed algorithm does not only apply on video but on still images as well, a collection of experiments are also applied on various content images and compared with previous work in terms of image metrics and statistics. keywords: spiht, bi-orthogonal, decimated, wavelets transform video, histogram. فديوي سري على أساس االخفاء بأستخدام التحويل المويجي المقسم وذو المرشح الثنائي أتصال (spiht) المتعامد والمشفر المدرس المساعد أحمد تومان ذهب وااللكترونية هندسة الكهربائيةال/قسم ةكلية الهندس/جامعة كربالء الخالصة االخفاء هو القابلية الخفاء معلومات سرية في وسط غطائي بدون ان يميز الناظر وجود هذة المعلومات سرية. يوجد طرق مختلفة لحمل البيانات سرية والتي تكون عادة صورة او فايل صوتي. في هذا البحث تم اقتراح طريقة أخفاء فديو سري في فديو الغطاء. حيث mailto:toeahmed@gmail.com mailto:toeahmed@gmail.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 بأستخدام طريقة تقسيم الشجرة المتشاكلة والتحويل المويجي المخفض ذو الثنائي العامودي. المعلومات السرية يتم تشفير الفديو السري يتم أخفائها في مجال التحويل المويجي للغطاء في ثالث حزم التي تحتوي على طاقة قليلة من خالل استبدال معامالت الغطاء لعملية على كل أطار من أطارات الفديو السري والغطاء والذي يؤدي الى أنتاج فديو بالمعامالت الفديو السري المجفرة. يتم تطبيق ا وذو جودة عالية بأستخدام مقاطع الفديو القياسية وفديو أخر تم التقاطة من كاميرا الهاتف الخلوي. مخفي غير قابل للكشف وقوي الخوارزميه ومقارنة النتائج مع والثبات أن الخوارزميه تعمل ليس فقط في الفديو وأنما في الصوره الثابته, تم أختبار صور ثابته على .أعمال مناظره list of symbols q: coefficients of dwt for the secret video. mse: mean square error. nc&sc: normalized correlation and structure correlation, respectively. psnr: peak signal to noise ratio. h(a): set of coefficients. spiht: set partitioning in hierarchical trees. β: control factor for preset capacity. 1. introduction various kinds of vital data are being transferred through the internet and exposed to various number of threats, therefore; many techniques of information hiding, such as steganography, are growing more important by the day. when mentioning information hiding, three solid concepts are the foundation of any information hiding scheme which are; capacity robustness, and imperceptibility. capacity is the number of secret bits which can be concealed the cover pixels; imperceptibility is the quality of the cover data after embedding secret. robustness is the ability of the method to withstand certain attacks and eventually prevent secret data from being stolen. for a satisfying information hiding system, a compromise between the three concepts is essential [1]. steganography is the ability to conceal secret data in a cover data without highly decanting neither the cover data nor the quality of the reconstructed secret data. there are many embedding algorithms to conceal data; one of the simplest algorithms is the least significant bit insertion. many other steganography algorithms have been developed such as spread spectrum embedding. a steganographic system is divided into two systems; spatial methods and signal transform methods. in spatial domain methods, the embedding operation is conducted directly on pixel values. the main benefit of this operation is its simplicity to implement but it possesses a limited ability to tolerate signal processing operations. methods based on signal transform, the cover image is converted to various transform domains where the coefficients of the image is processed. the coefficients produced are then retransformed to the previous domain to produce the image has contains the secret data called the stego data[2]. the benefit based on this method is the ability to conduct signal processing operations. there are many signal transforms that fall under this partition such as dwt, dct&dft. as steganography plays an important role in today's computer technologies, many researchers have conducted vital researchers in this field. the paper published by hao-tian [3], presented an algorithm for steganography using al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 029 adjacent bin mapping (abm), it maps the coordinates with a couple of adjacent bins when applied on three dimension geometrics, the statistics of the image cover are preserved with reduced rate of distortion. paper [2] proposed a method on using edge detection thus detecting as many edge pixels as possible. a combination of two types of detector; canny edge and fuzzy edge detector. the secret data is embedded depending on edge and non-edge pixels. the paper shows the range of psnr (51.1db18.5db) depending on the payload embedded. paper (sneha [4]) proposed a method to embed data in rgb image edges, the edges are determined by scanning the image by 3x3 window. a paper shabir [5] suggested a high capacity data hiding referred to 4r-4g-4b. the color image is divided into biplanes followed by data embedding. the paper proposes to embed secret data in pseudorandom positions. this method proposes to improve the psnr by 2.7db. a steganography technique using signal transform was proposed as a method to embed data in the transform domain, hemalatha, [6] where secret data is embedded in the horizontal, vertical and diagonal components of the cover media. a. verma, [7] used the discrete wavelet transform on the cover image; a second level discrete wavelet transform is applied on the hh band. the method proposes to change from the left corner of the analyzed hh band to replace 5 lsb with 5 msb of the secret data. a. al-taby, [8], utilized the discrete wavelet transform to embed a one dimension data in the wavelet domain. a threshold calculation is used to identify the size of redundancy. the algorithm uses encryption to encrypt the message in the wavelet domain. depending on the payload, the psnr varies between (40.98-22.84db). other authors m.ghebleh, [9] proposed an image steganography algorithm based on lifted discrete wavelet transform and a three dimensional chaotic map, the algorithm is fast, efficient and flexible. this paper introduces a new steganography technique which is applied on video cover. a secret video is hidden inside a cover video and many metric parameters are used to gage the performance of the algorithm. an insight regarding bi-orthogonal decimated wavelet transform and spiht encoding is presented. references mentioned can be reviewed for further reading. 2. biorthoganol decimated wavelet transform the wavelet transform which is widely used in signal analysis, it is a powerful tool to present local frequency domain information of a particular signal. wavelet transform has the ability to disclose discontinuities and breakdown points [10]. the continuous wavelet transform is conducted via contraction and dilation of what is called mother wavelet. in order to analyze an image in wavelet domain, a bank of filters is used analyze and reconstruct the image. a group of bank filters splits a two dimension signal in different frequency content bands which is computed by low and high pass filtering for the rows and columns of a two dimension signal. this will produce the following subbands: a(n,m) i , d h (n,m) i , d v (n,m) i , d d (n,m) i in figure.(1)[11]. symatric wavelets are principally created using biorthgonality, which are generally used in various image processing applications. biorthogonal filters are two filters, one is utilized for decomposing the input frame and the other is utilized for decomposition. it is referred to it by (bior d/r). the letters d and r represent the length of decomposition and reconstruction filters [12]. 3. spiht encoding wavelet properties are exploited using spiht algorithm where the coefficients are encoded at a specified bit rate [13]. the bits generated are used to reconstruct the original wavelet coefficients. spiht algorithm is independent on the information order since it depends on a branching point comparison. it is a symmetric enc/dec. a magnitude test in eq. (1) is applied on a set of coefficients [14]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 020 | | (1) if the set h(a) applies to eq.(1). then the coefficients are momentous. the momentous subsets are further divided into new subsets. subsets ̅ are further partitioned to other subsets during the execution of the algorithm. the coefficients are classified as [14]. 1. lis: list of non-momentous sets. 2. lip: list of non-momentous nodes. 3. lsp: list of momentous nodes. pixels in lip that are found non-momentous in the previous pass are tested. if they become momentous, they will be moved to lsp . if a single coordinate is found non-momentous then it is added to lip otherwise it is added to lsp (3) the algorithm will stop until a bit rate of (ß) which is eventually a control factor is satisfied [14]. 4. proposed video steganography video steganography is the process of hiding secret data in a video cover whilst preserving the quality of video cover. the secret data may be sound, image, and video. in this paper, a digital color video steganography is proposed to hide secret video data in a secret video cover in the wavelet domain of the cover video. primarily, the secret data is pre-processed to convert secret video data into a determined three levels of data and insert them in the wavelet domain of the cover video. figure.(2) shows the block diagram of the proposed video steganography: secret video is primarily separated into a group of frames; each frame is input to a seven level decomposition, biorthognal discrete wavelet transform. each frame is converted to a group of coefficients; the next stage implies encoding the coefficients using spiht codec. spiht codec converts coefficients to a sufficient binary number depending on the momentous coefficients, number of coefficients differ according to β factor. increasing the β factor increases the number of binary bits to embed resulting a degraded stego-video/image quality. the number of coefficients is vital and applies to the following condition: ∑ (2) where: w j (i): is the number of output coefficients from the sphit codec : is the number of coefficients for all bands except for a(n,m) i band. therefore; stego output quality varies depending on β factor. cover video is splitted into frames and each frame is separated to three color channels. a one level decimated discrete wavelet transform is applied on each frame resulting four bands a(n,m) i , d h (n,m) i , d v (n,m) i , d d (n,m) i , the a(n,m) i is left since most of the a(n,m) i coefficients are highly essential. the rest of the bands are utilized in embedding the binary bits: al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 embedding bands (eb) i = (3) equation (3) combines the bands of the wavelet domain bits are embeded in the resulted band according to eq.(4): while condition (2) is applied: = (4) lsp (5) where: ̅̅ ̅̅ is the new coefficient in the decimated wavelet domain. is the coefficient of spiht codec. f : frame index. k, z: spatial pixel index. i: color channel index. 5. steganoanalysis when the stego video/image is received, the steganoanalysis deframes and splits each frame to three color channels. the algorithm extract the ̅̅ ̅̅ values from d h (n,m) i , d v (n,m) i , and d d (n,m) i and delivers them to lis map for the spiht algorithm to decode. an error will introduced for the extracted value duo to the forward and backward transformation. the spiht algorithm will update the wavelet coefficients. it is known that when an input is inserted to the lsp, the absolute value of that input is bounded between 2 n and 2 n+1 , this information provided in addition to the bit sign will result 2 n [14]. original values will be retained to form a single frame for the video footage. 6. results and discussion in order to demonstrate the performance of our algorithm, results are presented in this section. mainly the experiments carried out are on standard video movies and images. results produced from the algorithm imply many number of parameters, such as psnr, mse, sc and nc for the stego and secret video recovery. another parameter is the human vision system (hvs) to compare the quality between the stego and cover video. for an extra mile to prove the algorithm’s integrity, it will be tested on various images and compare the results in terms of mentioned parameters with previous work. the comparison is also illustrated using hvs. all the experiments are conducted using matlab 2010b: 6.1 experiments on video movies this section will introduce results regarding video movies as inputs to the algorithm. two videos (secret and cover) with various lengths are input. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 a. video parametric performance: this refers to the objective performance of the algorithm such as psnr, mse, normalized correlation and structural correlation. various number of frames are input with various ß factor as shown in table.(1). increasing the β factor decreases the psnr of the cover video since more bits are embedded in the cover video frames, this will result in more degradation in the stego-frames and eventually the video as a whole. as for the reconstructed secret video, the psnr is increased when β factor is increased since more bits are representing the coefficients of the secret video. the value of nc and sc which illustrates the correlation in terms of frame and structure content are approximately in the range of (10.999) respectively as illustrated in table. (1). the time required to process the algorithm is increased when attaining a high secret video quality. b. histogram shape preservation: steganography is a main process in security where secret data is being transmitted in a cover media without noticing, figure.(3) shows the histogram for the two random video frames. the shape of the histogram for the stego and cover video are the identical which mean this algorithm preserve pixel distribution for the mentioned video and communicating through the algorithm will not alert attackers. c. human visual system (hvs): reconstructed frames are exposed in figure. (4) to reveal and asses the quality of the reconstructed frames attained from the algorithm. stego and cover frame looks identical from a human point of view in terms of texture, color and content. it is correlated to the corresponding cover frame video. as for the secret video reconstruction, reconstructed random video frame show that there is an amount of blurriness in the reconstructed frame but without deep effect on the frames texture or colorness which is shown in figure.(5). 6.2 experiments on still images in order to demonstrate the algorithm is not merely applicable on video movies but also on still images, a group of images are input on the algorithm. the work will be compared with previous work such as in paper [15] three images which are similar to the ones used in [15] are used as input to the algorithm. the sizes are 128*128 gray scale images. a. image metric parameter: since the work in [15] depends on psnr with various payloads, we will compare the proposed work using the same parameter. comparing the results attained from our algorithm and the results illustrated in [15] as shown in table.(2). it is obvious that our algorithm has superior performance in terms of psnr to that in [15] using the same payload and images. the maximum psnr for the proposed method is (41.85) while psnr for the work in [15] is (39.93). another work has been compared [16] as shown in table.(3). reviewing the reference, it is pick able that the proposed algorithm in image application is better. b. histogram shape preservation: regarding histogram shape preservation, figure.(6) illustrates the histogram for the stego and original cover image. the figure shows the identically between the stego and cover images. c. human vision system: figure.(7) shows the stego and cover for baboon image. from a human point of view, the images are similar. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 7. conclusion in this paper, a video/image steganography is presented using spiht codec which tends to conceal a video inside video cover media. the algorithm divides the secret media into tm subsets and classifies it to three categories, lip, lis and lsp using biorthogonal decimated wavelet transform. the resulted bits are embedded inside a single frame/image cover media in the three combined vertical, horizontal and diagonal wavelet bands. experimental results illustrates that the proposed method produces a high psnr with less mse. as ß factor increases the quality of the stego video will degrade but the reconstructed secret video will increase, in addition to preservation of structural image and shape of pixel distribution. this goes in-line with the principle of steganography. proposed algorithm is applied on images and compared with corresponding work. it produces a high psnr with a considerable payload which is the same mentioned in the work compared to. references [1] johnson.n, duric, z. & jajodia, s. information hiding: “steganography and watermarkingattacks and countermeasures”. boston, ma: kluwer academic publishers, vol.1, pp.77-109, (2001). [2] wen-jan chen, chin-chen chang and t. hoang ngan le, “high payload steganography mechanism using hybrid edge detector” published in expert systems with applications-elsevier pp.3292–3301, 2010. [3] hao-tin wu and jean –luc dugelay,” steganography in 3d geometries and images by adjacent bin mapping”, hindawi publishing. eurasip journal on information security, volume, pp.30-40, 2009. [4] sneha arora, sanyam anand, “a new approach in image steganography using edge detection method” international journal of innovative research in computer and communication engineering vol.1, issue 3, pp. 626-629, 2013. [5] shabir a. parah, javaid a. sheikh, g. m. bhat,” data hiding in color images: a high capacity data hiding technique for covert communication” published in computer engineering and intelligent systems, vol.4, no.13, pp.107-115, 2013. [6] hemalatha s, u dinesh acharya, renuka a, priya r. kamath, “a secure color image steganography in transform domain” published in international journal on cryptography and information security (ijcis), vol.3, no.1, pp.17-24, 2013. [7] a. verma, r. nolkha, a. singh and g. jaiswal,”implementation of image steganography using 2-level dwt technique” gautam buddh technical university, published in international journal of computer science and business informatics. issn: 1694-2108, vol. 1, no. 1, 2013. [8] a. al-ataby and f. al-naima, “a modified high capacity image steganography technique based on wavelet transform”, published in the international arab journal of information technology, vol.7, no.4, pp.358-364, 2010. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 [9] m.ghebleh, a.kanso,” a robust chaotic algorithm for digital image steganography”, university of kuwait. published in commun nonlinear sci numer simulat journal, elsevier, vol.19,issue 6, pp.1898-1907, 2013. [10] dubechies, “orthonormal bases of compactly supported wavelets”, communication in pure and applied mathematics, vol. 41, pp. 909-996, 1988. [11] wavelet toolbox user’s guide in matlab r2010b. [12] k. a. kotteri, a. e. bell, and j. e. carletta, “implementations of the biorthogonal 9/7 dwt: convolution versus lifting”, ieee transactions on circuits and systems, vol.52, no.5, pp.256260, 2005. [13] b. mohanty, a. singh & s. mahapatra,” a high performance modified spiht for scalable image compression”, international journal of image processing (ijip), vol. 5, issue.4, pp. 390401, 2011. [14] r.sudhakar, ms r karthiga, s.jayaraman,” image compression using coding of wavelet coefficients – a survey”, icgst-gvip journal, vol. (5), issue (6), pp 25-38, 2005. [15] lifang yu, yao zhao, rongrong ni,” improved adaptive lsb steganography based on chaos and genetic algorithm”, eurasip journal on advances in signal processing volume 2010, article id 876946, pp-6, 2010. [16] h. rashidy kanan, b. nazeri,” a novel image steganography scheme with high embedding capacity and tunable visual image quality based on genetic algorithm”, published in expert systems with applications elsevier, vol.41, pp.6123-6130, 2014 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 time (sec) nc of sec psnr of sec sc of steg nc of steg psnr of steg mse of steg β video name (cov, sec)& no .frame 53.480 0.997 24.858 1.0001 0.999 45.649 1.773 30 sunset and viptraffic (115) 79.444 0.998 27.644 1.0002 0.999 42.8765 3.356 60 121.32 0.998 30.275 1.0004 0.9996 40.7554 5.466 90 46.316 0.999 28.158 1.0001 0.9999 45.936 1.782 30 soccer& hinos (114) 78.407 0.999 31.563 1.0002 0.999 43.275 3.329 60 117.96 0.999 33.839 1.0003 0.999 41.242 5.234 90 47.158 1.000 36.303 1.0001 0.9999 46.2458 1.568 30 xylophone &viptrafic (115) 77.138 1.000 38.422 1.0001 0.9998 43.6817 2.840 60 121.32 0.998 39.700 1.0004 0.9996 42.183 4.023 90 46.529 0.995 28.399 1.000 1.000 52.729 0.346 30 news& grandma (115) 74.585 0.997 31.431 1.0002 0.999 45.773 1.720 60 109.84 0.997 33.467 1.001 0.999 38.947 8.377 90 31.993 0.997 27.779 1.0001 0.9998 44.624 3.236 30 street& viplane(80) 54.716 0.998 30.902 1.0003 0.9997 41.022 7.038 60 78.859 0.998 33.201 1.0007 0.9993 38.016 13.58 90 49.032 0.999 28.645 1.000 1.000 52.841 0.338 30 occean& vipdeparture (115) 79.385 0.999 32.015 1.000 1.000 52.152 0.396 60 107.51 0.999 34.159 1.000 1.000 51.09 0.506 90 table (1): illustrates the results for various β and video. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 022 table (2): shows the results for the proposed method and previous work. name of test image payload in bpp psnr in db of work psnr in db of [15] lena 0.46 41.85 39.93 0.642 40.40 38.52 0.731 39.77 37.37 baboon 0.46 22.22 33.59 0.642 22.12 33.05 0.731 33.42 32.38 plane (jet plane) 0.46 41.51 38.73 0.642 40.61 37.58 0.731 40.20 36.72 name of test image name of secret image psnr in db of work psnr in db of [16] lena lena pattern 256*256 51.42 45.12 jet 22.88 45.18 pepper 45.85 45.13 a. original frame b. 2done level dwt figure (1): analyzed single frame using dwt. table (3): shows a comparison between present and previous work with 40kb secret image. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 021 steg video cover video secret video combining frequency bands one level, 2d dwt coefficient embedding and capacity check color video framing seven level, 2d biorthognal dwt sphit codec altering α factor video frame separation figure (2): shows the proposed video steganography using spiht codec. β control a. stego frame b. original cover frame c. stego frame d. original cover frame figure (4): shows stego and original cover and stego frames for various exp.(2&6). 0 100 200 300 400 500 600 700 800 pixel value f re q u e n c y o f a p p e re n c e 0 50 100 150 200 250 for the stego frame for the cover frame figure (3): shows the histogram for the stego and cover video for frame index one. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 092 a. stego image b. original image figure (7): shows the stego and original image for baboon image. 0 50 100 150 200 pixel value f re qu en cy o f a pp er an ce 0 50 100 150 200 250 original image stego image figure (6): shows the histogram shape for original and stego image. a. secret frame b. original secret frame c. secret frame d. original secret frame figure (5): shows secret and the original video frames for exp.(1&4). republic of iraq al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 165 analysis of stress concentration and deflection in plates under static loading dr. abdul wahab hassan khuder assistance professor technical college baghdad akhuder@yahoo.com summary: the effect of stress concentration and deflection in plates with circular holes subjected to concentrated load is studied. different hole sizes and distance from the plate center (x) are tested experimentally and compared with a reference plate without hole. the specimens are classified into two groups, the first represents specimens containing hole leis in the x-axis of the plate group (a) , and the second group represents the specimens containing two half hole leis at the edge of plate group (b). the results are analyzed using finite element method (fem), which gives good agreement with the experimental deflection data. the specimens which have central hole group (a) or side two half hole with the same diameter group (b) give lower deflection than that the plate without hole for the same cross sectional area. increasing hole diameter gives a reduction in the deflection values for each specimen. group (b) give a higher deflection value for a wide range of (x) as comparing with those of hole specimens group (a). the maximum stress (σx) is higher in groups as comparing with the reference plate for wide range of (x). when this distance (x) increased, the value of maximum stress is reduced for groups. the same behavior is found when increasing the hole diameter. key words: stress concentration and deflection, plates under static loading. ركز األجهاد واألنحراف في الصفائح المسلط عليها حمل متمركزمتتحليل د.عبدالوهاب حسن خضر أستاذ مساعد بغداد -الكلية التقنية :المستخلـص نحرافها أالمسلط عليها حمل متمركزعلى ت الفجوة الدائرية ذا ائحفي الصف ركز األجهاد واألنحرافمتدراسة تأثير تتم يةساسأعن مركز الصفيحة ومقارنتها مع صفيحة مختلفة حجام فجوات ومسافاتأر اختبتم أفي هذا العمل جهاد فيها. أوأقصى ( b)والثانية , للعينة تحوي فجوة واقعة على المحور السيني (a) ولىمجوعتين األالى العينات تم تصنيف تجويف. على ويتتحال جيدة مقارنة مع نتائج عطت أوالتي ,. تم تحليل النتائج بطريقة العناصر المحددة الصفيحة تحوي نصفي الفجوة واقعة عند حافات على تحتوي ال والتي ساسيةاألالصفيحة قل مقارنة مع أنحراف أعطت مقدار أمن العينات ولى والثانية . المجموعة األ النتائج العملية على أنحراف أعطت مقدار أالمجموعة الثانية . نحراف لكال المجموعتينالفجوة أدى الى نقصان مقدار األزيادة قطر .تجويف يكون أعلى في المجموعتين مقارنة مع تلك (σx)أن أقصى أجهاد لوحظكما (. xالمسافات ) ولى لمدى واسع منمقارنة مع األ mailto:akhuder@yahoo.com al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 166 نفس التصرف عند كما تمت مالحظة ,وعند زيادة تلك المسافة فأن أقصى أجهاد يقل(. x) من المسافاتبدون فجوة لمدى واسع زيادة قطر الفجوة. 1. introduction: in order to link the concept of stress concentration with the elasticity theory, it is necessary to determine the stress field around the hole in an infinite plate. the analysis of stress concentration factor (scf) of adjacent holes in a spherical pressure vessel can be approached by considering a thin plate undergoing hydrostatic stresses [1]. the von misses stress is considered to determine the scf, various arrangements of adjacent holes are investigated i.e., two, three, four, and five adjacent holes are taken into account. the scf curves with respect to the ratio of the distance between adjacent holes to the diameter of hole, (l/d), and for a certain ratio of the diameter of hole to the plate thickness, (d/t), are then plotted. the results show that the decreasing of (l/d) will affect the increasing of scf, while for the case of five adjacent holes configuration, the increasing of (d/t) doesn’t make any significant effect to the increasing of scf [2]. examines the efficiency of an adhesively bonded reinforcement patch in reducing the stress concentration around a hole in a plate, as a function of hole size. a stress concentration factor is defined as the tangential stress in the plate at the hole boundary, compared to that far away in the plate but still under the reinforcement [3]. the distributions of stresses and deflection in rectangular isotropic and orthotropic plates with central circular hole under transverse static loading have been studied using finite element method (fem). the (d/a) ratio (where (d) is the hole diameter and (a) is plate width) is varied from (0.010.9). the analysis is done for plates of isotropic and two different orthotropic materials. the results are obtained for three different boundary conditions. the variations of scf and deflection with respect to (d/a) ratio are presented in graphical form and discussed. the finite element formulation is carried out in the analysis section of the package [4]. in the case when an anisotropic plate contains a triangular, oval, or square opening, the only solution available in the literature is an approximate solution for orthotropic plates with openings. the solutions presented here have only one simple unified expression for various openings such as the ellipse, circle, crack, triangle, oval, and square. two special loading conditions are considered form. the results show that the effect of an isotropy on the stress concentration is totally determined through the fundamental elasticity matrices [5]. 2. material descriptions and specimens preparation: the material used in this work is pure aluminum (aa1050) where the chemical composition is listed in table (1). a tensile test specimen is machined as in figure (1) to achieve the mechanical material properties. the dimensions of reference plate used in this work is made from a sheet of plate have a thickness of (t = 1mm); a width (w = 21mm) and a length of (l = 90mm). the cross sectional area of this plate is (21 mm²). the value of cross sectional area will be assumed as a reference to compare the results. two groups of holed plate are prepared such that the cross sectional area remains the same as in the reference plate. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 167 2.1 group (a): to explain the effect of central hole on the values of stress and deflection, the plate is drilled with central hole along the longitudinal center line. hence the width of reference plate (w=20mm). specimens are made such that the net width remains the same and results in equal cross sectional area. the center of hole is the same that the center of plate, that means the distance (x) in figure (2), (x=0 mm). the net sectional area of this group (a) is shown schematically in figure (3). therefore, the width and hole diameter values of specimens are assumed as in table (2). 2.2 group (b): the same specimen dimensions mentioned in group (a) are made for group (b). but the hole is divided in two half circle at the edges of plate to predict and compare the effect of side half holes with that the same of central hole, as shown in figure (4). the cross section area of this group (b) is shown schematically in figure (5). 3. experemental work: a concentrated force is applied along the center line of plate parallel to the width of plate. this force will give a maximum deflection in the center line of plate, figure (6). the concentrated load is increased gradually from zero value until reach the value of (f=10n) where the deflection of plate is record. 4. finite element model: the stress and deflection of plates are analyzed with finite element method. the following steps are done for each plate [6]:  define the element type (elastic 4 nodes 63).  define the real constant for the above element (using thickness t = 1mm).  define the material property (e=70000 n/mm 2 , v = 0.3).  molding area (drawing the specimen groups and the reference plate).  meshing the specimen with fine mesh.  applying the boundary conditions.  applying the concentrated force (f=10n).  solve the current model.  plot the results of stress and deflection for each specimen.  5. results and discussions: the results of this work can be classified into:  central deflection results include the experimental and the fem results.  results of maximum stress in plate (σx). to compare the results between all specimens with the reference plate, the same cross sectional area, the applied concentrated load (f=10n) and the boundary conditions are used as mentioned in al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 168 the experimental work. figure (7) represents the variation of central deflection with the horizontal distance for five widths of specimens (w=27-35mm), group (a). as comparing with the reference plate, the deflection of plates for group (a) is lower than that for the reference plate. that means; making a central hole in the plate will result in decreasing the deflection (for the same cross sectional area, force and boundary conditions). also for the same hole diameter, the deflection will decrease as the horizontal distance (x) increase for each specimen. increasing the hole diameter for the same value of (x) results in decreasing the value of central deflection. figure (8) represents the behavior of deflection with the distance (x) for five specimen widths (w=27-35mm), group (b). where the deflection for all specimens is lower than that of the reference plate and decrease with increasing hole diameter for the same distance (x). it has been shown that the deflection increases gradually for each specimens width with increasing the distance from (x=0–5) mm, and reach maximum value at (x=5mm).after this, the deflection decreases with increasing (x). a sample specimen is taken to show the results of stress distribution in the x-axis (σx) for all nodes of plate specimen. the specimen is from group (a) with the dimensions of (w=35mm, d=14mm), where the distance have a range of (x=0, 5, 10, 15, 20, 25 mm) in figures (9-14) respectively. it has been observed that the maximum stress decreases from (σx=82mpa) found around the hole, figure (9), and (σx=45 mpa) found at the center of plate. the maximum stress found around the hole has a small amount as shown in figures (9 -11), (x=0, 5, 10 mm). this is due to the effect of stress concentration in the curved area of hole circle. this effect reduces gradually as the distance (x) increases and the amount of maximum stress will appear in the center of plate as in figure (12), (x=15mm). the amount of maximum stress will be larges in the plate center than that around hole, figure (13), (x=20mm). when the value of (x) reaches (x=25mm), figure (14), the maximum stress is appears at the center of the plate, where the effect of the curved area is diminished. that means the effect of concentration of stress around hole is reduced as the distance (x) increases. 6. conclusions: the following conclusions are presented: 1the specimens which have central hole group (a) or side hole group (b) gives small deflection than that the plate without holes, the value of central deflection is decrease with increasing the distance (x) for groups. 2increasing hole diameter gives a reduction in the deflection values for each specimen of groups. 3the maximum stress (σx) is higher in groups as compared with the reference plate for wide range of (x). increasing the distance (x) reduce the value of maximum stress for groups. 4maximum stress is at the center of specimens for the ranges (x=0 -15mm).and the maximum stress is found only at the center of specimens for the value of (x=25mm). 5the amount of maximum stress transfers from the location of hole surrounding to the plate center as the distance (x) increases. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 169 7. references: [1] (fuad1 kh., et al, 2007) “stress concentration factors of various adjacent holes configurations in a spherical pressure vessel” 5th australasian congress on applied mechanics, acam, brisbane, australia. [2] (pickthall c. and rose l.f., 1998) “stress concentration around a patched hole in an axisymmetrically loaded plate” aeronautical and maritime research laboratory commonwealth of australia. [3] (nitin kumar jain, 2009) “analysis of stress concentration and deflection in isotropic and orthotropic rectangular plates with central circular hole under transverse static loading” world academy of science, engineering and technology. [4] (chyanbin hwu, 1990) “anisotropic plates with various openings under uniform loading or pure bending” transactions of the asme vol. 57. [5] (rao k.p., 2001) “stress concentration and stability studies in composite ribs with flanged cutouts”, cae group, infosys technology limited, bangalore, india. [6] (james doyle, 2004) “finite element methods”, john wiley & sons, ltd. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 170 table (1) chemical compositions of aluminum specimens (aa1050). al si fe cu mg mn cr ni zn ti ag b bi be 99.5 0.173 0.225 0.0125 0.0045 0.0215 0.0043 0.0051 0.0113 0.0163 0.00062 0.0028 0.001 0.0028 table (2) dimensions of group (a) specimens. 5 4 3 2 1 specimen no. 35 33 31 29 27 w(mm) 14 12 10 8 6 d(mm) 1 1 1 1 1 t(mm) 21 21 21 21 21 a=(w-d)*t figure (1) tensile test specimen. figure (2) shape of group (a) specimens. ca cd co hg la li na p pb sn sr v zr 0.00045 0.00035 0.001 0.0021 0.0005 0.0002 0.00099 0.001 0.0027 0.001 0.0001 0.005 0,0003 x w t group a l d al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 171 figure (3) cross sectional area of group (a) specimens. figure (4) shape of group (b) specimens. figure (5) cross sectional area of group (b) specimens. d w t w t d/2 d/2 x w t r=d/2 group b l load group a load group b load reference plate al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 172 figure (6) boundary conditions and concentrated load of specimens. 0 5 10 15 20 25 the horizontal distance from hole center to plate center ,x, (mm) 0.700 0.800 0.900 1.000 c e n tr a l d e fl e c ti o n , w , (m m ) experimental figure (7) variation of central deflection with the distance for group (a). 0 5 10 15 20 25 the horizontal distance from hole center to plate center ,x, (mm) 0.700 0.800 0.900 1.000 c e n tr a l d e fl e c ti o n , w , (m m ) ansys al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 173 figure (8) variation of central deflection with the distance for group (b). figure (9) variation of stress (σx) for the distance (x=0 mm). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 174 figure (10) variation of stress (σx) for the distance (x=5 mm). figure (11) variation of stress (σx) for the distance (x=10 mm). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 175 figure (12) variation of stress (σx) for the distance (x=15 mm). figure (13) variation of stress (σx) for the distance (x=20 mm). al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 176 figure (14) variation of stress (σx) for the distance (x=25 mm). 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 تأثير تظليل و طالء أسطح األبنية على ظاهرة االحتباس الحراري بغداد -بشير هاشم حليحل / مدرس مساعد/ معهد التكنولوجيا )hashembasheer@yahoo.com) 1024 آيار 12ُقبل 1024 أذار 17ُأستلم المستخلص: لقد تم دراسة تأثير تظليل و طالء أسطح األبنية على كمية ثاني أوكسيد الكاربون المنبعثة إلى الجو نتيجة لمستخدمة في تكييف بيئة المباني و بالتالي على ظاهرة االحتباس الحراري لمدينة استهالك الطاقة الكهربائية ا بغداد حيث وجد أن تأثير وضع مظلة مصنوعة من مادة القصب هو اختزال أكبر في كمية الطاقة المستخدمة في تكييف بيئة المباني و ثاني اوكسيد الكاربون المطروح إلى الجو من استخدام األسطح المطلية بينما يوجد 25coبالون األبيض و الرصاصي و األسود في األشهر التي تكون درجة الحرارة أكبر من إضافة أكبر في كمية الطاقة المستخدمة في تكييف بيئة المباني و ثاني اوكسيد الكاربون المطروح إلى الجو ي و األسود في األشهر عند استخدام سطح مظلل بدل استخدام األسطح المطلية بالون األبيض و الرصاص وقد وجد أن رفع المظلة في األشهر التي تكون درجة الحرارة أقل من 25coالتي تكون درجة الحرارة أقل من 25co يحسن أداء األسطح المظللة و يجعلها أفضل من األسطح ذو الطالء األبيض ويقرب أداءها من طاقة الكهربائية المستخدمة في تكييف بيئة المباني و األسطح ذو اللون األسود و بالتالي يقلل من استهالك ال ثاني اوكسيد الكاربون المطروح إلى الجو فتقل تأثيرات ظاهرة االحتباس الحراري. الكلمات الرئيسية: تظليل, طالء, ثاني أوكسيد الكاربون, الطاقة الكهربائية, ظاهرة االحتباس الحراري mailto:hashembasheer@yahoo.com mailto:hashembasheer@yahoo.com 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 the effect of shading and painting the surfaces of building on global warming basheer hashem hlihl /assist lecturer/institute of technology/baghdad abstract: the object of this paper, is to study the effect of shading and painting the surfaces of buildings on the amount of carbon dioxide emitted into the atmosphere as a result of the consumption of electrical energy used in buildings for air conditioning and thus on global warming for the city of baghdad. it was found that the effect of an umbrella made of reeds is the largest reduction in the amount of energy used to adapt the built environment and carbon dioxide to the atmosphere arises from the use of white, gray and black surfaces in the months that temperature is greater than 25co.while there is in addition a larger amount of energy used to adapt the built environment and carbon dioxide to the atmosphere arises from the use of painted surface with color white, gray and black in the months that the temperature is less than 25co. it has been found that lifting of an umbrella in the months that the temperature is less than 25co improves performances of surfaces shaded and makes it better than the surfaces with white paint and nearly performance of surfaces with black color and thus reduces the consumption of electric power used in the air conditioning of building and carbon dioxide into the atmosphere and less effects of global warming. key words: shading ,painting, carbon dioxide, electrical energy, global warming 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 الرموز المستخدمة في البحث: المعنى الرمز المعنى الرمز a er&a ℮ g h k qcond qconv. qrad. qtrans. rcon. المساحة السطحية للسطح النسبة المئوية المضافة أو المختزلة في الطاقة نسبة إلى السطح الرصاصي االنعكاسية طحطاقة اإلشعاع الوارد إلى الس معامل انتقال الحرارة بالحمل معامل انتقال الحرارة بالتوصيل كمية الطاقة الحرارية المنتقلة بالتوصيل كمية الطاقة الحرارية المنتقلة بالحمل كمية الطاقة الحرارية المنتقلة باإلشعاع كمية الطاقة الحرارية المنتقلة عبر السطح مقاومة انتقال الحرارة بالتوصيل rconv tso tsi tr to t x α ρ ԏ σ مقاومة انتقال الحرارة بالحمل رجة حرارة السطح الخارجيد درجة حرارة السطح الداخلي درجة حرارة الغرفة درجة حرارة الجسم الباعث لإلشعاع درجة حرارة المحيط سمك السقف االمتصاصية العاكسية النفاذية ثابت بولتزمان : المقدمة درجة مئوية و تدل الدراسات 0.5سنة الماضية بمقدار150 األرض قد ارتفعت خالل أن درجة حرارة جو السبب المباشر لهذا ، أن2075( درجة مئوية في عام 1.5-4.5بأن درجة حرارة جو األرض سترتفع بين ) يبة من االرتفاع هو إرسال البشر إلى الجو مجموعة من الغازات قادرة على حبس الحرارة في طبقات الجو القر سطح األرض مثل غاز ثاني أوكسيد الكاربون و الميثان و أوكسيد النيتروز و بخار الماء )أ.د عبد القادر,أ.د إن غاز ثاني اوكسيد الكاربون بصورة عامة هو الغاز الذي يتلقى أغلب التركيز و االهتمام .(2004غازي, الرغم من أن تفاعالته تكون أقل خطورة من باقي عند دراسة الغازات القادرة على حبس الحرارة في الجو على % من تأثير الغازات القادرة على 60ولكن بقاءه في الجو يكون لفترة أطول حيث أن تأثيره يمثل ،الغازات 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 طرح إلى الجو ما 1860أن النشاط الصناعي البشري و منذ عام .(houghton,1997 (حبس الحرارة مليار طن من الكاربون( نتيجة حرق الوقود 260اوكسيد الكاربون ) مليار طن من غاز ثاني 950يقارب إن استخدام الوقود .(iea/oecd,1999اإلحفوري والذي يشمل الفحم و النفط الخام و الغاز الطبيعي ) ،% سنويا في كمية ثاني اوكسيد الكاربون المطروحة إلى الجو2اإلحفوري سوف يسبب زيادة تراكمية مقدارها مليار طن من الكاربون( في 6.3مليار طن من ثاني اوكسيد الكاربون )23الدراسات طرح حيث بينت bolinأن نصف هذه الكمية سوف تبقى في الجو و النصف اآلخر يستنفذ بالعمليات الطبيعية ) ،1997عام et al.,2000). رح العلماء و لقد أقت ، هذا التراكم أدى إلى رفع درجة حرارة جو األرض درجة مئوية واحدة للحفاظ على هذا االرتفاع بدرجات الحرارة يجب خفض كمية ثاني أوكسيد الكاربون المطروحة إلى الجو أن أهم القطاعات المساهمة في زيادة نسبة .( .watson et al 2001% )80% إلى 60مستقبال بحدود حيث يساهم هذا ،بائية الحراريةثاني اوكسيد الكاربون المطروحة إلى الجو هي محطات توليد الطاقة الكهر % و 23% من نسبة ثاني اوكسيد الكاربون المطروح إلى الجو باإلضافة إلى قطاع النقل 32القطاع بنسبة من هنا يتضح إن محطات الطاقة الكهربائية تساهم بنسبة كبيرة ،%25% والفعاليات األخرى 20الصناعة تقليل هذه النسبة و ذلك عن طريق عدد من األساليب منها في انبعاث ثاني أوكسيد الكاربون و لهذا يجب وكذلك عن طريق تقليل كمية الطاقة الكهربائية المستخدمة حيث ،تحسين كفاءة محطات الطاقة الكهربائية ( كيلو غرام من ثاني اوكسيد 452,583،920أثبتت الدراسات إن لكل ميكا وات ساعة منتجة سوف يبعث ) ستخدام الغاز الطبيعي و النفط و الفحم على التوالي كوقود إلنتاج الطاقة الكاربون في حالة ا (.أن التفسير العلمي لهذا السلوك للغازات التي تسبب االحتباس الحراري هو أنها baden,2000الكهربائية) عثة و بما أن الطول الموجي لألشعة المنب،تمتص األشعة ذات األطوال الموجية الطويلة أكثر من القصيرة من األجسام تتناسب عكسيا مع درجة حرارتها و لهذا فأن األشعة المنبعثة من الشمس )درجة حرارة سطح ( 0.5تكون معظمها قصيرة الموجة و معدل الطول الموجي لإلشعاع الشمسي هو )°( م 6000الشمس كون معظمها أشعة ت°( م 15بينما األشعة المنبعثة من األرض )معدل درجة حرارة سطح األرض ،مايكرون وهذه األشعة ذات الطول الموجي الكبير ،مايكرون( 12-8ذات أمواج يتراوح معدل طولها الموجي بحدود ) هي التي تستطيع الغازات المشار إليها أعاله امتصاصها مما يؤدي إلى رفع درجة حرارة الجو)أ.د هرة االحتباس الحراري( ال تحدث (. أي بعبارة أخرى إن تسخين و تبريد الغالف الجوي )ظا2008قصي, بسبب اإلشعاعات القادمة من الشمس بل تعتمد على اإلشعاعات المنبعثة من سطح األرض )د. عايد (.أن نسبة األشعة الممتصة من قبل ثاني أوكسيد الكاربون و بخار الماء والمنبعثة من قبل 2110راضي, و أن .(2008خلة إلى الغالف الجوي )أ.د قصي,% من األشعة الكلية الدا15سطح األرض تتراوح بحدود 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 %من أجمالي استهالك الطاقة األولية في العراق )عاطف علي 70عن أكثر من مسؤولةالمباني الحالية (% من 50-20و كما إن النسبة المستهلكة من الطاقة إلغراض التكييف بحدود ) .(2008ومثنى لطيف, هذه النسبة توضح مدى تأثير عملية تكييف .(2009عاطف علي,أجمالي الطاقة المستهلكة في العراق ) األبنية و خصوصا في المناطق الحارة على ظاهرة االحتباس الحراري لما تطلقه محطات توليد الطاقة الكهربائية لغاز ثاني أوكسيد الكاربون عند إنتاجها للكهرباء في الجو. حيث تقدر نسبة األنبعاثات العالمية من لهذا يجب تقليل قدر ، %24سيد الكاربون و الناتجة من استخدام الطاقة الكهربائية لألبنية بحدود ثاني أوك اإلمكان هذه النسبة عن طريق استخدام أسلوب زيادة مقدار قيمة المقاومة الحرارية لألبنية و خصوصا تخدام عوازل % من إجمالي ما يستلمه المبنى و ذلك باس20السقوف حيث يستلم طاقة شمسية بحدود أو باستخدام أسلوب تقليل كمية الطاقة الحرارية التي تصل إلى السقف باستخدام ،(hasan,1984حرارية) أو جعل السقف يميل بزاوية ،(amori & baqir,2009تقنية المواد ثنائية الطور ) ،(2011راء أو المائية )عاطف علي,أو باستخدام المسطحات المائية الخض ،(2009معينة )عاطف علي , أو بزيادة مقدار االنعكاسية ألسطح األبنية لألشعة الشمسية الساقطة عليه و ذلك بطالئها باللون األبيض )ذو % من سطح 1حيث أكدت دراسة تمت في الواليات المتحدة األمريكية أن تغطية .%(55انعكاسية تقدر ف الجو بما يعادل التأثير السلبي الناتج عن كل السيارات في العالم الكرة األرضية باللون األبيض سوف يلط akbari et al. ,2009))، أو باستخدام سقوف تظلل أسطح المباني لعكس األشعة الشمسية إلى الفضاء مباشرتا لمنع امتصاص سطح األرض لألشعة الشمسية ثم بثها إلى الفضاء مرة ثانية وبالتالي تقليل تأثير حتباس الحراري و هذا ما تم دراسته في هذا البحث حيث تم استخدام سقيفة مصنوعة من مادة ظاهرة اال محلية )القصب( فوق سطح المبنى لتكوين منطقة ظل على سطح المبنى وقد كانت منطقة البحث مدينة بغداد. الجانب العملي : يئة المباني عن طريق األسطح فقد تم لتحقيق الهدف من هذا البحث في تقليل كمية الحرارة المنتقلة إلى ب طالء أسطح مجموعة من الغرف الموجودة في الطابق الثاني في مدينة بغداد حيث كانت قياسات الغرف 0.6(متر ذو سطح مكسو بمادة الشتايكر )ذو اللون الرصاصي( و بقياس )4x5المستخدمة في التجارب ) x0.6ود و األبيض باإلضافة إلى اللون األصلي للشتايكر ( متر حيث تم طالء أسطح الغرف بالون األس وهو اللون الرصاصي مع تجنب عدم وجود ظل يغطي منطقة أداء التجارب أثناء النهار كما و استخدمت مظلة مصنوعة من مادة القصب المحلي )وهي مادة ليس لها تأثير سلبي على البيئة( ألحداث منطقة ظل 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 جارب و قد سجلت درجات الحرارة باستخدام محرار زئبقي مغطى بمادة على سطح أحدى الغرف في أحدى الت عازلة إال من جهة بصلة المحرار و جهة التدرج لتجنب امتصاص المحرار ألي كمية من الحرارة إثناء عملية قياس درجة حرارة السطح . : الجانب النظري ى انتقال الحرارة المنتقلة بواسطة األشعة الشمسية إن عملية انتقال الحرارة من الجو إلى بيئة المباني تعتمد عل إلى السطح الخارجي ألسطح المباني بواسطة اإلشعاع الحراري وهو عبارة عن إشعاع ذات موجات ( ميكرومتر. عند سقوط األشعة الشمسية على 100-(0.1كهرومغناطيسية تنبعث بأطوال موجية تتراوح بين ص و يسمى الجزء الذي يمتصه السطح من اإلشعاع الساقط السطح فأن قسم من اإلشعاع سوف يمت ( و قسم آخر سوف ينعكس إلى الجو و يسمى الجزء الذي يعكسه السطح إلى الجو αباالمتصاصية ) ( بينما القسم األخير سوف ينفذ من السطح في حالة أن الجسم الذي تسقط عليه األشعة شفاف ρبالعاكسية ) (. و من موازنة الطاقة يمكن أن نشتق العالقة بين ԏاإلشعاع الوارد بالنفاذية )و يسمى الجزء الذي ينفذ من الخواص الرئيسية لإلشعاع. طاقة اإلشعاع الوارد إلى السطح = الطاقة المغادرة للسطح + الطاقة الممتصة g= αg+ (ρg +ԏg) α + ρ +ԏ = 1 ԏ=1=صفر ، ρ = صفر ،αا تكون للمواد المعتمة )غير شفافة( بينم ρ + α=1= صفر و ԏو تكون للجسم األسود و تعتمد امتصاصية و عاكسية و α =1 =صفرρ = صفر ،ԏلمعظم الغازات و تكون نفاذية األجسام بصفة عامة على درجات حرارة مصدر اإلشعاع و طبيعة األسطح و أن كمية الحرارة المنتقلة إلى السطح الخارجي للمبنى تحسب بالقانون التالي: qrad.= ℮ σ a ( to4 – t4) تتراوح بين صفر و الواحد و هي تعتمد على درجة حرارة وطبيعة السطح .)ا.د أحمد صابر ℮حيث أن قيمة (1989و اخرون, وبعد ذلك سوف تنتقل الحرارة الممتصة من قبل سطح المبنى إلى سقف المبنى و المتكون من مجموعة جص البياض وبما إن هذه المواد هي مواد صلبة فأن االنتقال طبقات وهي الشتايكر و رمل و كونكريت و الحراري خالله يسمى بالتوصيل و تحسب كمية الحرارة المنتقلة بالقانون التالي )ارتين ليفون و زهير (:1983ساركو, 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 qcond.= -k a (tsotsi)/x ف هو أحادي البعد وان كمية و قد تم حساب كمية الحرارة المنتقلة خالل سقف المبنى على أساس إن السق الحرارة المخزونة خالل السقف مهملة. وبعد أن تنتقل الحرارة الممتصة من قبل سطح المبنى خالل سقف المبنى سوف تنتقل إلى بيئة الغرف عن طريق انتقال الحرارة بالحمل و يحدث الحمل حينما يتواجد سطح متالمس مع مائع ذي درجة حرارة يختلف ارته و هناك نوعان من انتقال الحرارة بالحمل هما الحمل الطبيعي حيث تتم حركة المائع في عن درجة حر هذا النوع بقوى طبيعية )فرق في كثافة المائع (أما الثاني فيدعى الحمل القسري حيث تنشأ حركة المائع بفعل مصدر خارجي و تحسب كمية الحرارة المنتقلة في هذا النوع بالمعادلة التالية qconv.= h a (tsi-tr) إن كمية الحرارة المنتقلة إلى بيئة المبنى سوف تعتمد على مقدار المقاومة للسطح )االنتقال بالتوصيل( و ( وكذلك على مقدار المقاومة للمائع داخل المبنى )االنتقال بالحمل( و rcon.=x/kaتكون المقاومة تساوي ) ( و لتسهيل عملية الحسابات سوف نفرض إن انتقال rconv.=1/haتكون المقاومة في هذا النوع تساوي ) الحرارة خالل السطح و بيئة الغرفة هو أحادي البعد و في حالة مستقرة و ال يوجد تراكم أو تخزين للطاقة (. ولحساب كمية الحرارة المنتقلة في حالة استخدام 1989خالل طبقات السطح)ا.د أحمد صابر و اخرون, لل نسبة إلى السطح الرصاصي ) لون الشتايكر( نعمل االتي:سطح مطلي أو سطح مظ qcond.=∆t/(x/ka) → qcond.= (tso –tsi)/rcon. qconv.= ∆t/(1/ha) → qconv.=(tsi-tr)/rconv. qtrans.= (tso – tr)/ (rcon. + rconv. )= ∆tdiff./ rtotal (qtrans.)colure or shadow /(qtrans.)gray = {(∆tdiff./ rtotal) colure or shadow /(∆tdiff./ rtotal) gray} (qtrans.)colure or shadow /(qtrans.)gray= {(∆tdiff.) colure or shadow /(∆tdiff.) gray } qr&a = {1 – ( ∆tdiff. colure surface or shadow / ∆tdiff. gray surface)} (*) المناقشة:النتائج و فترة خالل دراسة السلوك الحراري ألسطح الغرف و ذلك برسم درجة حرارة السطح الخارجي مع الزمن أثناء النهار نالحظ أن درجة حرارة السطح تزداد عند تغيير لون السطح من األبيض إلى الرصاصي )الشتايكر( ثم إلى األسود و هذه الزيادة في درجة حرارة السطح تتناسب مع التغير في قيمة األنبعاثية لألسطح حيث تكون 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 19 متغيرات التي تحدد كمية الطاقة الممتصة لألبيض أقل من الرصاصي و هذا اقل من األسود و بما أن باقي ال من قبل سطح الغرفة و التي تشمل المساحة السطحية و درجة حرارة اإلشعاع ثابتة فان قيمة األنبعاثية كلما قلت فهذا يعني أن كمية الطاقة الممتصة من قبل السطح قد قلت و بالتالي فأن درجة حرارة السطح الخارجي قانون امتصاص الحرارة باإلشعاع . أما في حالة السقيفة فأننا سوف نحجب للغرفة سوف تقل وذلك حسب اإلشعاع و نمنعه من الوصول إلى السطح الخارجي و بالتالي تتكون منطقة ظل ال يكون لإلشعاع إي تأثير على سطح المبنى و أن ارتفاع درجة حرارة السطح سوف يحدث نتيجة انتقال الطاقة الحرارية التي يحملها الهواء الخارجي إلى سطح الغرفة و تكون طبيعة انتقال الطاقة الحرارية في هذه الحالة هو االنتقال بالحمل ( نالحظ إن منحني درجات الحرارة لسطح األبيض هو أدنى من منحني درجات 1الطبيعي.ومن خالل شكل ) ارة للسطح األسود كما و أننا الحرارة لسطح الرصاصي )الشتايكر( و هذا بدوره أدنى من منحني درجات الحر نالحظ أن منحني درجات السطح المظلل هو أدنى من باقي المنحنيات و هذا يدل على أن السطح األبيض يعكس أشعة الشمس الساقطة عليه بصورة أكبر من السطح الرصاصي و هذا بدوره أكبر من السطح األسود عليه و بالتالي ال وجود المتصاص األشعة أما في حالة السطح المظلل فال وجود النعكاس األشعة )الحرارة(على سطحه بصورة مباشرة ولهذا فأنه يمتلك أقل درجات حرارية مسجلة ألسطح الغرف كما و نالحظ ( أن معدل درجات الحرارة ألسطح األبنية المظللة و ذو اللون األبيض و الرصاصي 1من خالل جدول رقم ) ,39,37.6,34.4,31.5)) (,47,45,41,36.5)هي كاألتي ( 1,5,10,7و األسود و لألشهر ) ( 1درجة مئوية على التوالي. من خالل جدول رقم) 16.5 ,19.6,18.5) 14.5,، )(36,33.5,30,27.5) نالحظ عند استخدام سطح مظلل يوجد اختزال في الطاقة المستخدمة في تكييف األبنية مقارنة في حالة )الشتايكر( و بالتالي يحدث اختزال في كمية ثاني أوكسيد الكاربون أسطح األبنية ذات اللون الرصاصي وباستخدام معادلة )*( يتم حساب النسبة المئوية المختزلة و المضافة من الطاقة و من المطروحة إلى الجو, لى حيث تكون نسبة االختزال في الطاقة و في كمية ثاني أوكسيد الكاربون المطروحة إ ثاني أوكسيد الكاربون تكون و .على التوالي%42,%48,%70) ( هي )5,10,7الجو في حالة استخدام سطح مظلل و لألشهر ) الكمية المختزلة لثاني اوكسيد الكاربون في حالة استخدام الغاز الطبيعي و النفط إلنتاج الطاقة الكهربائية و ميكاوات ساعة على لكل co2كيلو غرام 408,280,248)( و )316,217,192لألشهر السابقة هي ) ( كيلو غرام من ثاني 452,583حيث أثبتت الدراسات إن لكل ميكا وات ساعة منتجة سوف يبعث ))التوالي اوكسيد الكاربون في حالة استخدام الغاز الطبيعي و النفط على التوالي كوقود إلنتاج الطاقة ن نسبة االختزال في الطاقة وفي (. إما في حالة استخدام سطح ذو لون أبيض فأbaden,2000الكهربائية) ( على %20,%25,%41( هي )5,10,7كمية ثاني اوكسيد الكاربون المطروحة إلى الجو و لألشهر ) 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 التوالي و تكون الكمية المختزلة لثاني اوكسيد الكاربون لهذه الحالة في حالة استخدام الغاز الطبيعي و النفط ( 239,145,117, ) 90.4 ,113 ,185)و لألشهر السابقة هي )إلنتاج الطاقة الكهربائية لتكييف األبنية لكل ميكاوات ساعة على التوالي عند مقارنتها بأبنية ذات أسطح ذو لون رصاصي. أما في co2كيلو غرام حالة استخدام سطح ذو لون أسود فيوجد إضافة في الطاقة المستخدمة في تكييف األبنية و في كمية ثاني لمطروحة إلى الجو حيث تكون نسبة الطاقة المضافة و كمية ثاني اوكسيد الكاربون اوكسيد الكاربون ا ( وتكون الكمية %10,%10 ,%27(هي )(5,10,7المطروحة لألبنية ذات اللون األسود و لألشهر شهر المضافة من ثاني اوكسيد الكاربون في حالة استخدام الغاز الطبيعي و النفط إلنتاج الطاقة الكهربائية لأل لكل ميكاوات ساعة على التوالي عند مقارنتها co2( كيلو غرام 157,58,58( )112,45,45السابقة هي ) بأبنية ذات أسطح ذو لون رصاصي. من هنا يتضح أن السطح المظلل هو أحسن السطوح المستخدمة في ر كانون الثاني فتبين درجة مئوية. أما نتائج القياسات لشه 25األشهر التي ترتفع درجة حرارة الجو عن وجود انخفاض في معدل درجات حرارة السطح المظلل و األبيض مقارنة بمعدل درجة حرارة السطح الرصاصي و هذا يعني و جود إضافة في الطاقة المستخدمة في تكييف األبنية و بالتالي في كمية ثاني ضافة و للسطح المظلل و األبيض هي اوكسيد الكاربون المطروحة إلى الجو حيث تكون النسبة المئوية لإل ( على التوالي و تكون الكمية المضافة من ثاني اوكسيد الكاربون لهذه الحالة في حالة استخدام 60%,30%) ( كيلو 175,350( )136,271الغاز الطبيعي و النفط إلنتاج الطاقة الكهربائية لشهر كانون الثاني هي) الي كما إننا نالحظ وجود اختزال قليل في الطاقة عند استخدام لكل ميكاوات ساعة على التو co2غرام و أن كمية ثاني اوكسيد %17السطح ذو اللون األسود في فصل الشتاء حيث تكون نسبة االختزال هي الكاربون المختزلة في حالة استخدام الغاز الطبيعي و النفط إلنتاج الطاقة الكهربائية لشهر كانون الثاني هي لكل ميكاوات ساعة على التوالي. من هنا يتضح إن سطح األبنية ذات اللون co2كيلو غرام ( 99,77) األسود هو األفضل في فصل الشتاء الن النسبة المئوية للطاقة المبذولة لتكييف بيئة المباني و كمية ثاني أن فصل الشتاء في اوكسيد الكاربون المطروحة إلى الجو قليلة مقارنتا بباقي أنواع السطوح األخرى إال العراق و خصوصا في مدينة بغداد و هو المكان الذي أجريت فيه موضوع البحث قليل )تقريبا ثالث أشهر( مقارنتا بفصل الصيف، إال إننا من الممكن تحسين كفاءة السطح المظلل في فصل الشتاء و ذلك عن طريق سطح إلى أشعة الشمس بصورة مباشرة و صنع سقوف متحركة يمكن تحريكها في فصل الشتاء ليتعرض ال بالتالي تقل كمية الطاقة المستهلكة في تكييف بيئة األبنية و كمية ثاني اوكسيد الكاربون المطروحة إلى الجو ونتيجة لهذا األجراء األخير على السطح المظلل في فصل الشتاء فأن كفاءته سوف تقترب من كفاءة السطح تخدام السطوح المطلية باأللوان لها تأثير سلبي على البيئة لما تطرحه مصانع ذو اللون األسود. كما أن اس 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 911 ولها كلفة مادية أكبر من السطوح المظللة لما تحتاجه من و البيئة إنتاج الطالء من مواد مضرة بالصحة ح تجديد الطالء كل سنة خصوصا في الظروف البيئية لمدينة بغداد من هنا يتضح لنا أن استخدام السطو المظللة ذات السقوف المتحركة هي أفضل من السقوف المطلية باللون األبيض وخصوصا لظروف المناخية لمدينة بغداد بصورة خاصة و العراق بصورة عامة. االستنتاجات: لقد أتضح و من خالل النتائج إن استخدام السطح المظلل يعطي اختزال اكبر في كمية الطاقة الكهربائية ي تكييف بيئة األبنية و بالتالي في كمية ثاني اوكسيد الكاربون المطروح إلى الجو من السطح المستخدمة ف ذو الطالء األبيض والرصاصي )االعتيادي ( و األسود خالل فصل الصيف، وأما في فصل الشتاء فأن جعل أداءه أمكانية رفع السطح المظلل ممكنة مما يحسن أداء السطح و يجعله أفضل من السطح األبيض و ي قريب من السطح األسود و بالتالي فأن كمية ثاني اوكسيد الكاربون المطروح إلى الجو سوف تقل ويقل معها تأثير ظاهرة األحتباس الحراري. التوصيات: كمية المواد الملوثة األخرى نتيجة استخدام الوقود اختزال دراسة تأثير طالء أسطح المباني و تظليلها على .لتكييف بيئة المباني مثل كبريتيد الهيدروجين و فناديوم و نيكل ري في إنتاج الطاقة الكهربائيةاألحفو المصادر: amori, dr. kerima e. & baqir ameer k. ‘‘ analysis of thermal energy storage system with two phase flow”, the 6th engineering conference, college of engineering, university of baghdad, iraq-2009 atif ali hasan (optimum insulation thickness for iraqi walls & roofs) symposium of thermal insulation in hot climates-scientific research council-iraq 1984 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 919 baden-daettwil, alstom power technology, internal communication, switzerland,2000 bolin, b., robert, t.w., ian, r.n., david, j.v. et al, ipcc special report, ‘‘ land use, land-use change and forestry ”, cambridge university press, u.k, 2000, pp375 hashem akbari, surabi menon, arthur rosenfeld ‘‘ global cooling: increasing world-wide urban albedos to offset co2” journal climatic change, june 2009, volume 94, issue 3-4, pp 275-286 houghton, j., ‘‘global warming: the complete briefing”, cambridge university press, 1997 iea/oecd, ‘‘co2 emissions from fuel combustion”, 1999 watson, d., conry, r.d., ipcc working group i contribution to the ipcc third assessment report ‟ climate change 2001: the scientific basis”, shanghai, january 17-20,2001 , انتقال الحرارة ,الطبعة المترجمة 1191ا.د أحمد صابر,ا.م.د مصطفى محمد,ا.م.د ماجد إبراهيم, 063األولى,دار العربية للنشر و التوزيع , صفحة ĩ,121باني, الطبعة األولى, جامعة بغداد,صفحة , أنشاء الم1190رتين ليفون , زهير ساركو , أساسيات علم البيئة,الطبعة الثانية,دار وائل للطباعة و 2332ا.د عبد القادر عبد ,ا.د غازي سفاريني , 193النشر,صفحة الغذاء(, الطبعة األولى,دار اليازوري العلمية -الماء-,التلوث البيئي)الهواء2313د. عايد راضي خنفر, 20شر و التوزيع,صفحة للن , تقليل التسرب الحراري من السقوف الخرسانية لألبنية السكنية بتغير زاوية 2331عاطف علي حسن , 219-292جامعة بابل, صفحة \كلية الهندسة\ميلها,المجلة العراقية للهندسة الميكانيكية و هندسة المواد 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 919 طاقة المستهلكة في القطاع السكني في العراق, , تحليل مسارات ال2339عاطف علي حسن, مثنى لطيف , العراق-النجف -الكلية التقنية -المؤتمر العلمي األول , تقليل كمية الحرارة المنتقلة من سقف المبنى المعرض للبيئة باستخدام تقنية 2311عاطف علي حسن , 020-011فحة كانون األول,ص 11,مجلد6المسطحات الخضراء أو المائية, مجلة الهندسة,العدد ,مبادئ الطقس و المناخ, الطبعة األولى,دار اليازوري العلمية 2339ا.د قصي عبد المجيد السامرائي, .96للنشر و التوزيع,صفحة المختزلة أو المضافة باستخدام أنواع من co2و كمية co2النسبة المئوية من الطاقة و -( :1جدول ) الوقود األشهر تموز لتشرين األو ايار كانون األول اسود ابيض ظل اسود ابيض ظل اسود ابيض ظل اسود ابيض ظل حالة السطح معدل درجة حرارة السطح (co) الخارجي 36.5 41 47 31.5 34.4 39 27.5 30 36 14.5 16.5 19.6 )+( النسبة المئوية المختزلة ( من الطاقة و -أو المضافة ) co2. )*( بأستخدام معادلة +42 +20 1048 + 25 + 10 +70 +41 -27 -60 -30 +17 أو ( -) المضافة co2كمية باستخدام الغاز )المختزلة )+ ( kgco2/mwhالطبيعي) في إنتاج الطاقة 192+ 90.4 + 45 +217 +113 -45 +316 +185 -122 -271 -136 +77 أو ( -)المضافة co2كمية باستخدام زيت )المختزلة )+ ( في kgco2/mwhالغاز ) إنتاج الطاقة +248 + 117 -58 +280 +145 -58 +408 +239 -157 -350 -175 +99 درجة حرارة الغرفة المطلوبة (co) 25 25 25 25 معدل درجة حرارة السطح (co) الرصاصي)االعتيادي( 45 37.6 33.5 18.5 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 919 و تموز و تشرين الثاني أيارالثاني و ( : درجة حرارة سطح الخارجي لألبنية ألشهر كانون1شكل ) 0 20 40 60 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 ة ر را ح ال ة ج ر د ( ( c ° (ساعة)الزمن درجة حرارة السطح الخارجي لشهر تموز ظل أبيض رصاصي أسود 0 5 10 15 20 25 30 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 ح ط س ال ة ر را ح ة ج ر د )°( c (ساعة)الزمن درجة حرارة السطح لشهركانون الثاني ظل أبيض رصاصي أسود 0 10 20 30 40 50 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 رة را ح ال ة ج ر د (° (c ( ساعة) الزمن درجة حرارة السطح الخارجي لشهر تشرين األول ظل أبيض رصاصي أسود 0 20 40 60 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ح 21 ط س ال ة ر را ح ة ج ر د (°( c (ساعة)الزمن درجة حرارة السطح لشهر ايار ظل أبيض رصاصي أسود 4102 3العدد 7مجلة القادسية للعلوم الهندسية المجلد 919 (: السقيفة المستخدمة 3(: أحد األسطح المطلية شكل )2شكل ) للتظليل al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 343 numerical simulation of thermal performance of constant conductance cylindrical heat pipe using nanofluid hassanain ghani hameed foundation of technical education engineering technical college/ najaf automobile department hasgh77@yahoo.com proof. dr. abudl-muhsin a. rageb university of basra engineering college mechanical engineering department muhsin rageb@yahoo.ie received 6 june 2014 accepted 1 september 2014 abstract in this work, a two-dimensional numerical model has been developed to study the thermal performance of a cylindrical heat pipe utilizing nanofluids. al2o3-water based is considered as the working fluid. the numerical model represented as steady-state incompressible flow. the governing equations in cylindrical coordinates have been solved in vapor region, wick structure and wall region, using finite deference with forward-backward upwind scheme. a substantial change in the heat pipe liquid pressure drop, temperature difference, maximum heat transfer limit, capillary pressure and thermal resistance is observed when using a nanofluid. the nanoparticles within the liquid enhance the thermal performance of the heat pipe by reducing the thermal resistance and temperature difference by 0.168 k/w and 5.06 k respectively. while increasing the maximum heat load and the capillary pressure by 96 w and 192.46 pa respectively. all these results at input heat of 30 w and nanoparticles concentration of 5 vol. %.the results of wall temperature distribution for the heat pipe have been compared with the previous study for the same problem and a good agreement has been achieved. keywords: cylindrical heat pipe; nanofluid; numerical simulation. أ.د. عبد المحسن عبود رجب جامعة البصرة كلية الهندسة قسم الهندسة الميكانيكية حسنين غني حميد هيئة التعليم التقني الكلية التقنية الهندسية / النجف قسم هندسة تقنيات السيارات الخالصة: ئع الدقيقاحراري اسطواني باستخدام الم بألنبوتم تطوير نموذج عددي ثنائي البعد لدراسة االداء الحراري ,في هذا البحث لة المستقرة. تم حل المعادالت انوع االلومينا المخلوط بالماء. تم تمثيل النموذج العددي بالجريان الالانضغاطي في الح )النانوفلود( ة الفروقات المحددة مع نظام الجدار باستخدام طريق منطقةالفتيل و تركيب بصيغة االحداثيات االسطوانية في منطقة البخار, الحاكمة خلف مع الريح. تم مالحظة تغير حقيقي في هبوط الضغط, فرق درجة الحرارة, حد انتقال الحرارة االعظم, الضغط الشعري -أمام وب و المقاومة الحرارية لالنبوب الحراري عند استخدام مائع دقيق. وجود الدقاق النانوية ضمن المائع يعزز االداء الحراري لالنب بينما يزيد الحمل الحراري على التوالي. k 5.06 و k/w 0.168نحو عن طريق تقليل المقاومة الحرارية وفرق درجة الحرارة و تركيز w 30حيث ان كل هذه النتائج عند كمية حرارة .على التوالي pa 192.46و w 96نحو االعظم و الضغط الشعري al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 344 ة النتائج الخاصة بتوزيع درجات على جدار االنبوب الحراري مع الدراسات السابقة وكان تم مقارن. .% .vol 5الجزيئات الدقيقة هنالك توافق جيد. 1. introduction heat pipes have been the center of attention as high heat transfer devices for a couple of decades. during the time of heat pipe development two approaches have been followed in order to enhance the heat pipe heat transfer capacity and reduce its thermal resistance. one approach is to improve heat pipes’ structure including the pipe modification – e.g. using finned pipes, annular structure – and wick modification – e.g. new wick designs or wicks combinations. another approach is to seek better working fluids which are compatible with the heat pipe structure and have higher thermal properties. a novel idea, by applying nanofluids as working fluids in heat pipes, that can be found only in the literature of the last decade. this idea enhance the maximum heat transport rate and the effective thermal resistance which represent the main parameters that characterize the thermal performance of a wicked heat pipes (hajian et. al 2012, peterson 1994). nomenclature a = area (m 2 ) cp = heat capacity at constant pressure (kj/kg. k) da = darcy number h = convective heat transfer coefficient (w/m 2 . k) hfg = latent heat of vaporization (kj/kg) k = thermal conductivity (w/m. k) keff = effective thermal conductivity of the liquidsaturated wick (w/m. k) kp = permeability of the wick (m 2 ) l = length (m) leff = effective length of heat pipe (m) p = pressure (n/m 2 ) q = heat transfer (w) r = redial coordinate (m) rc = capillary radius of wick (m) r = gas constant (kj/kg. k) rth = thermal resistance (k/w) re = reynolds number pr = prandtl number t = temperature (k) u = axial velocity (m/sec) v = radial vapor velocity (m/sec) v = reference velocity (m/sec) x = axial coordinate (m) greek symbols ε = porosity of the wick φ = nanoparticle concentration ѱ = stream function (m 3 /sec) ω = vorticity (sec -1 ) α = fluid thermal diffusivity (m 2 /sec) υ = kinematics viscosity (m 2 /sec) μ = dynamic viscosity (kg/m. sec) σ = surface tension (n/m) ρ = density (kg/m 3 ) β = inclination angle of heat pipe θ = dimensionless temperature subscripts * = dimensionless term a = adiabatic c = condenser col = coolant e = evaporator f = base fluid in = inlet int = interface l = liquid n = nanofluid o = outer p = particle s = sink, solid sat = saturated set = set point v = vapor w = wick wa = wall superscripts ¯ = average quantity al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 343 (do et al. 2010) experimentally, investigated the effects of the water-based al2o3 nanofluids on the thermal performance of heat pipes with the volume fraction of 1.0 and 3.0 vol.%. based on the experimental results it is shown that the utilization of the waterbased al2o3 nanofluids as the working fluid enhances the thermal performance of the heat pipe and the volume fraction of nanoparticles has a great effect on the reduction of the wall temperature at the evaporator section. the thermal resistance of the heat pipe using the water-based al2o3 nanofluids with 3.0 vol.% is significantly decreased up to about 40% at the evaporator-adiabatic section as compared with that of the distilled (di) water-based heat pipe. also, it is shown that the maximum heat transfer rate of the heat pipes can be enhanced using the water-based al2o3 nanofluids instead of di water. (mousa 2011), presented an experimental study for the behavior of nanofluid to improve the performance of a circular heat pipe. pure water and al2o3-water based nanofluid are used as working fluids. the effect of filling ratio, volume fraction of nanoparticles in the base fluid, and heat input rate on the thermal resistance is investigated. total thermal resistance of the heat pipe for pure water and al2o3-water based nanofluid is also predicted. an experimental correlation is obtained to predict the influence of prandtl number and dimensionless heat transfer rate, kq on thermal resistance. thermal resistance decreases with increasing al2o3-water based nanofluid compared to that of pure water. an experimental study was performed to investigate the thermal performance of an inclined miniature mesh heat pipe using water-based cuo nanofluid as the working fluid by (wang et al 2012). the study focused mainly on the effects of the inclination angle and the operating temperature on the heat transfer performance of the heat pipe using the nanofluid with the mass concentration of cuo nanoparticles of 1.0 wt%. the experiment was performed at three steady operating temperatures of 40°c, 50°c and 60°c. experimental results show that the inclination angle has a strong effect on the heat transfer performance of heat pipes using both water and the nanofluid. the inclination angle of 45 ° corresponds to the best thermal performance for heat pipes using both water and the nanofluid. (liu 2011) performed an experiment concerning a cylindrical mesh wicked heat pipe. the working fluid was an aqueous cuo nanofluids. the results show that adding cuo nanoparticles into deionized water with concentration of 1.0 wt.% can enhance the evaporating heat transfer coefficient averagely 2.5 times, and the maximum heat flux of the heat pipe enhance by 42%. (naphon et al. 2008) investigated titanium–alcohol nanofluid effects on heat pipe thermal performance, for different working fluid charging amount, heat pipe tilt angle and nanoparticles volume concentrations. they found that nanoparticles enhance the heat pipe thermal performance. (tsai et al. 2004) used a circular meshed heat pipe with 170 mm length and 6 mm of outer diameter to investigate effects of structural character of gold nanoparticles in nanofluid on heat pipe thermal performance. they found that, there is a significant reduction in thermal resistance of heat pipe with nanofluids solution as compared with di-water. also the results show that the thermal resistance of a vertical meshed heat pipe varies with the size of gold nanoparticles. an experimental investigation is carried out by (solomon et al 2012) to study the thermal performance of a heat pipe operated with nanoparticle coated wick. the thermal resistance and heat transfer coefficient in the evaporator of the heat pipe operated with coated wick are lower and higher respectively than that of conventional one whereas the same are opposite in the condenser at three different heat inputs. the total resistance of heat pipe operated with coated wick is lower than that of conventional one and it decreases with increasing heat input. at the evaporator section, 40% thermal resistance reduction and 40% heat transfer coefficient enhancement are observed. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 343 (kang et al. 2006) investigated the effects of silver nanofluid on grooved circular heat pipe with 200 mm length and 6 mm diameter. they observed 10–80% decrease in thermal resistance of the heat pipe compared to di-water at an input power of 30-60 watt. the results also show that the thermal resistances of the heat pipe decrease as the silver nanoparticle size and concentration increase. (kang et al. 2009) used a sintered heat pipe to investigate effects of an aqueous solution of 10 and 35 nm diameter silver nanoparticles and its concentration on heat pipe thermal performance. their experiments demonstrated that the temperature difference decreased 0.56-0.65 o c compared to di-water at an input power of 30-60 w, and also heat transfer capacity of heat pipe increased from 50 w by using di-water to 70 w by using nanofluid as a working fluid. the transient and steady state thermal performances of a medium-sized cylindrical stainless steel meshed heat pipe have been investigated experimentally by (hajian 2012), utilizing both di-water and silver nanofluid, as the working fluids. the experiments have been performed under heat rates in the medium range, less than 500 w. nanofluids were used with concentrations of 50, 200 and 600 ppm. by applying 50 ppm nanofluid, the thermal resistance and the response time of the heat pipe decreased by 30% and about 20%, respectively, compared to di-water. furthermore, the steady state performance of both di-water and nanofluid were better at higher heat rates, about 500 w. whereas 50 ppm nanofluid, as the working fluid, enhanced the thermal performance of the heat pipe in comparison with di-water, the nanofluids with more concentration did not. in an analytical study about nanofluid performance in heat pipe, (shafahi et al. 2010), used twodimensional analysis to study the thermal performance of heat pipe utilizing nanofluids. their analysis was based on a comprehensive analytical model which was proposed by (zhu and vafai 1999). they considered nanoparticles al2o3, cuo, and tio2 in their study and investigated the effect of these nanoparticles on thermal resistance, temperature distribution, and maximum capillary heat transfer (mcht) of heat pipe. they observed reduction in the thermal resistance and enhancing the mcht of heat pipe. they established an optimum mass concentration for nanoparticles in maximizing the heat transfer limit. they also investigated the effect of particle size on the heat pipe performance and found that smaller nanoparticles have more effects on temperature gradient along the heat pipe. a mathematical model was developed by (do 2010), for quantitatively evaluating the thermal performance of a water-based al2o3 nanofluid heat pipe with a rectangular grooved wick. the results show that at the optimum conditions, the thermal performance for the nanofluid heat pipe was significantly enhanced by about 100% when only a small amount of nanoparticles less than 1.0 vol% is added into the base fluid. also, the thermal resistance of the nanofluid heat pipe tended to decrease with increasing the nanoparticle size. the heat transfer enhancement ratio ranged from 1.2 to 2.2 for the different nanoparticle size, working temperature, and input heat rate. from the comparison of the thermal performance using both di water and nanofluids, it is found that the thin porous coating layer formed by nanoparticles suspended in nanofluids is a key effect of the heat transfer enhancement for the heat pipe using nanofluids. in this paper a numerical model has been developed to study the effect of al2o3-water based nanofluid (as working fluid), volume fraction of nanoparticles in the base fluid, and heat input rate on the thermal performance of a heat pipe. the steady state incompressible flow has been solved in cylindrical coordinates in vapor region, wick structure and wall region, using finite difference method. the darcy’s law has been employed for momentum equation in porous media. the governing equations have been solved using upwind scheme. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 343 2. mathematical model a cylindrical heat pipe as shown in fig. 1 consists of three main parts, namely evaporator section, adiabatic section and condenser section. external heat source applied at the evaporator section causes vaporization of the working liquid. due to the pressure gradient, the vapor flows to the condenser section and it condenses when the heat removed from the condenser wall surface by free or forced convection. the capillary pressure created by the wick structure, pumps the condensed fluid back to the evaporator. this process will continue as long as there is sufficient capillary pressure to drive the condensate back to the evaporator. figure 1: schematic of a cylindrical heat pipe under consideration. 2.1 governing equations and boundary conditions the steady state incompressible laminar flow has been solved in cylindrical coordinates in vapor region, wick structure and wall region. the wick is assumed isotropic and saturated with the working liquid. the vapor injection and suction at the liquid-vapor interface are assumed to be uniform. 2.1.1 vapor region the governing equations in vapor region are continuity, navier-stokes and energy equations as follows, ( jiji 2006): 0 )(1       r rv rx u (1)                          2 2 1 2 2 r u r u rx u nx p r u v nx u u n  (2)                           22 2 1 2 2 r v r v r v rx v nr p r v v nx v u n  (3) al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 343                                  2 2 1 2 2 r t r t rx t n k r t v x t u n p c (4) the boundary conditions for vapor region are as following. the radial velocities at liquid-vapor interface (borujerdi and layeghi 2004):               c l a l e lx a l e l fgn h nc l v r c q c v a l e lx e l a v e lx fgn h ne l v r e q e v   2 0 0 2 (5) the temperature at the vapor-liquid interface of the evaporator and condenser is calculated approximately using clausius-clapeyron equation, (borujerdi and layeghi 2004). satnvp nvp fg h n r satnvt t , ln , 1 1 int   (6) the boundary conditions at both pipe ends are: 00     x t uv (7) at pipe centerline the symmetry boundary conditions are: 0&0,0        r t r u v (8) 2.1.2 wick structure the governing equations in wick structure are as follows, (fadhil 2006, mahjoub and mahtabroshan 2008): 0 )(1       r rv rx u (9) the darcy’s law has been employed for momentum equation in porous media: al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 343 uu n ρ p k fε u p k n εμ r u r u rx u n μ x p r u v n ρ x u u n ρ 21 2 2 2 1 2 2                           (10) vv n ρ p k fε v p k n εμ r v r v r v rx v n μ r p r v v n ρ x v u n ρ 21 2 22 2 1 2 2                            (11) s r t r t rx t eff k r t v x t u effp c                             2 2 1 2 2 )( (12) f is a geometric function based on the porous wick structure and is calculated as follows, (zhu and vafai 1999): 23 15075.1 f (13) the effective thermal conductivity and heat capacity of wick structure, is calculated from equation for screen wire mesh, (fadhil 2006, rashidian 2008). )14( )])(1()[( )])(1()[( s k n k s k n k s k n k s k n k n k eff k        sp c np c effp c )(1)()(   (15) the effective thermal conductivity, heat capacity and viscosity for a mixture (nanofluid) with spherical particles is given by (shahi 2010, ferrouillat 2011): )16( ])(22[ ])(22[   p k f k f k p k p k f k f k p k f k n k        pp c fp c np c )()(1)(   (17)   5.21      f n (18) the latent heat of vaporization of al2o3-water based nanofluid with 1, 3, and 5 vol.% concentration and 25 ±5 nm spherical particles for temperature range of 20-96 oc are measured experimentally and represented by the following equations: al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333        1271.15 2 19.119  fgf h fgn h (19) while, the surface tension of al2o3-water based nanofluid with the same above specifications for temperature range of 20-90 o c are measured experimentally and represented by the following equations:        18266.1 2 934.18  fn (20) since the phase change phenomena was not included in current model, for modeling latent heat of vaporization a heat sink was employed in evaporator section and a heat source was used in condenser section. the values of these terms are, (mahjoub and mahtabroshan 2008):                 c l v r w r c q c s a s e l v r w r e q e s ) 22 ( 0 ) 22 (   (21) the boundary conditions at both pipe ends are: 00     x t uv (22) the radial blowing and suction velocities at liquid-vapor interface (fadhil 2006):               caeae aee e lllxll fgn h nc l v r c q c v llxl a v lx fgn h ne l v r e q e v   2 0 0 2 (23) the temperature at the liquid vapor interface of the evaporator and condenser is calculated approximately using clausius-clapeyron equation, as shown previously in equation (6). the boundary conditions at both pipe ends are: 00     x t uv (24) al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 at wick-wall interface:            wa t n t r wa t wa k r n t eff k (25) 2.1.3 wall region at heat pipe wall the equation of thermal conduction was used in cylindrical coordinates, (mahjoub and mahtabroshan 2008): 0 2 2 1 2 2                    r wa t r wa t rx wa t (26) the boundary conditions in this region are as following: at both ends of heat pipe: 0   x wa t (27) at wall-wick interface, the boundary condition as in equation (25). at heat pipe external surface:                        caeae aee e lllxll s t o th r wa t wa k llxl r wa t lx e l o r e q r wa t wa k 0 0 2 (28) in conventional heat pipes, under steady-state operation, there exists a maximum capillary pressure that can be developed in wick structure. the maximum heat transport capillary limit for a heat pipe is achieved when the sum of the pressure losses along the circulation path of the working fluid reaches the maximum capillary pressure; that is c r n g p n p v p cap p cos2  (29) δpv can be neglecting, can substitute for pressure terms in equation (29), (reay 2006). al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333    sin max . cos2 eff gl n p k w a m eff l n n c r n                       (30)   c l a l e l eff l  2 2 1 (31) for waterbased nanofluid as working fluid and horizontal heat pipe the maximum liquid flow rate in the wick become:                    c r n eff l n p k w a n m    2 max . (32) thus, the maximum heat transport capillary limit may be written as, (reay 2006):                     c r n eff l n fgn h p k w a n q fgn hmq    2 max max . max (33) the saturation temperature inside the heat pipe can be calculated from the following equation, (cleary 2006):   s t s t set t q c q sat t           max (34) the thermal resistance, which represent the effectiveness of the heat pipe can be calculated from the following equation, (sreenivasa 2005): in q c t e t th r   (35) 3. method of solution the governing equations are discretized using a finite difference approach and the equations are solved using forward – backward upwind with collocated grid scheme. the physical domain of problem was separated into three main regions, namely; vapour region, wick structure and wall region. it is convenient, for the numerical analysis, to use the governing equations in terms of stream function and vorticity as: rr u    1 (36) al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 xr      1 (37) r u x         (38) now, after obtained the governing equations in terms of stream function and vorticity ,then they with the corresponding boundary conditions are transferred to the non-dimensional form using the following dimensionless quantities:   ])(22[ ])(22[ * 5.2 1 1* ;1 ** re;pr;; 2 2 1 * * ; 2 * ; * ; * ; * ;                      p k f k f k p k p k f k f k p k f k n k k f n f p c p p c f p c n p c p c v vr k p c s t sat t s tt v p p v o r o vrvv u u o r r r o r x x                                      (39) the solution procedure of the discretized equations is based on a line-by-line iteration method in the axial and radial directions using fortran power station program. the solution procedure of the numerical analysis which performed in the above separated region is as follows: 1calculate saturation temperature using equation (34). 2calculate velocity and temperature boundary condition at the vapor-liquid interface using equations (5) and (6). 3solve the equations of stream function and vorticity in vapour and liquid regions sequentially based on the velocities obtained in step 2 and the values of stream function and vorticity at the boundaries where the boundary conditions are applied. 4calculate the velocity components ( and ) by using the current values of stream function and the values at boundaries. 5solve the momentum equations in x-direction for vapour region and wick structure using the current values for velocities. 6solve the energy equations in vapour, liquid and wall regions sequentially by using the current values of stream function and the values at boundaries. the above procedure repeated until the convergence is achieved with relative error for the calculated parameters (ψ, ω, p and θ) equal to . fig 2 illustrates the flow chart for the current computer program in the present study. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 334 4. results and discussion the analysis of a cylindrical horizontal heat pipe was carried out by incorporating the effect of water based nanofluid, namely al2o3, in the present numerical model. 1, 3 and 5 vol.% concentration are chosen for particle size of 35nm. the performance of the heat pipe is investigated for different heat inputs. in which, the influence of nanofluid on liquid pressure drop, axial velocity, radial velocity, stream function, temperature difference, thermal resistance, maximum heat transport capability and capillary pressure is investigated. the specifications of the heat pipe are shown in table 1. as seen in, the dimensionless contours plot, fig.s 3 – 14. for the same heat input, the liquid pressure and stream line inside the heat pipe decreases when increasing the nanoparticle concentration (npc). this is due to an increase in the fluid density in the presence of more nanoparticles, as can be seen in equation (17). as a result of this increase in the nanofluid density, a slower liquid flow is observed. for the same nanoparticle concentration, when the heat transfer rate increase the mass flow rate increased so that the fluid velocities increased, which lead to increase the liquid pressure and stream line values. also, due to increasing the heat transfer rate the saturation pressure will increase, which in turn lead to increase the heat pipe operation temperature. fig. 15 show the effect of particle concentration levels on the temperature difference between evaporator and condenser for various heat loads. the figure shows that increasing the particle concentration decreases the temperature difference between the evaporator and condenser. the maximum heat transport capillary limit and the capillary pressure as function of particles concentration can be seen in fig. 16. increasing the nanoparticle concentration enhances the maximum heat transfer and the capillary pressure. this is due to an increase in the latent heat of vaporization and the surface tension with the nanoparticle concentration, as can be seen in equations (19 and 20). fig. 17 show the influence of different nanoparticle concentration levels on the heat pipe thermal resistance under different heat input. it can be seen that increasing the nanoparticle concentration decreases the heat pipe thermal resistance and provides a better performance. for example, the percentage enhancement in rth reaches up to 35.3% at heat transfer rate of 30w and npc = 0.05 compared to its value when using pure water. to verify the current numerical model of the heat pipe. the result of wall temperature distribution along the heat pipe is compared with the result of (do et al., 2010) for the similar problem. fig. 18 show a good agreement for the temperature distribution at 3 watt as transmitting heat power and npc of 0.01. 5. conclusion this paper deals with the thermal enhancement of the heat pipe performance, using alumina – nanofluid as the working fluid. in the present work, the di-water with alumina nanoparticles, for three concentration levels 1, 3 and 5 vol.%, in heat pipe was numerically simulated using fortran power station program. conclusions may be drawn from the results of the numerical model as follows:  the dimensionless parameters (liquid pressure, uvelocity, vvelocity, stream function and temperature distribution) of the heat pipe with nanofluid is lower than that with di-water.  the more alumina nanoparticles in the working fluid enhancement of the heat pipe performance expressed by of the performance curves (the temperature difference versus heat transfer rate). al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333  the maximum heat transfer rate and the capillary pressure increases as the nanoparticle concentration increases.  the thermal resistance of the heat pipe with nanofluid is lower than that with di-water. it is shown that the thermal resistance decreases as the concentration level increases.  results indicate that the alumina nanofluid has remarkable potential as working fluid for horizontal heat pipe of higher thermal performances. 6. refrencess [1] borujerdi a. n., layeghi m., “a numerical analysis of vapor flow in concentric annular heat pipes”, transaction of asme: journal of fluids engineering, vol. 126, pp.442448, 2004. [2] do k. h., ha h. j. and jang s. p., “thermal resistance of screen mesh wick heat pipes using the water-based al2o3 nanofluids”, international journal of heat and mass transfer 53 (2010) 5888–5894. [3] do k.h. and jang s.p., “effect of nanofluids on the thermal performance of a flat micro heat pipe with a rectangular grooved wick”, international journal of heat and mass transfer 53 (2010) 2183–2192. [4] fadhil o. t., “numerical and experimental study on a heat pipe with porous media wick”, ph.d. thesis, university of technology, 2006. [5] ferrouillat s., bontemps a., ribeiro j.p., gruss j.a. and soriano o., “hydraulic and heat transfer study of sio2/water nanofluids in horizontal tubes with imposed wall temperature boundary conditions”, international journal of heat and mass transfer 32 (2011) 424–439. [6] hajian r. , layeghi m. and sani k. a., “experimental study of nanofluid effects on the thermal performance with response time of heat pipe”, energy conversion and management 56 (2012) 63–68. [7] jiji latif m. , heat convection, © springer 2006. [8] kang s.w., wei w.c., tsai s.h. and huang c.c., “experimental investigation of nanofluids on sintered heat pipe thermal performance”, applied thermal engineering 29 (2009) 973–979. [9] kang s.w., wei w.c., tsai s.h. and yang s.y., “experimental investigation of silver nanofluid on heat pipe thermal performance”, applied thermal engineering 26 (2006) 2377–2382. [10] liu z.h. and zhu q.z., “application of aqueous nanofluids in a horizontal mesh heat pipe”, energy conversion and management 52 (2011) 292–300. [11] mahjoub s., mahtabroshan a., “numerical simiulation of a conventional heat pipe”, world academy of science, engineering and technology, vol. 39, pp. 117-122, 2008. [12] mousa m.g., “effect of nanofluid concentration on the performance of circular heat pipe”, ain shams engineering journal 2 (2011), 63–69. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2010.07.050 http://dx.doi.org/10.1016/j.ijheatmasstransfer.2010.07.050 http://dx.doi.org/10.1016/j.enconman.2011.11.010 http://dx.doi.org/10.1016/j.enconman.2011.11.010 http://dx.doi.org/10.1016/j.enconman.2010.07.001 http://dx.doi.org/10.1016/j.asej.2011.03.003 http://dx.doi.org/10.1016/j.asej.2011.03.003 al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 [13] naphon p., assadamongkol p. and borirak t., “experimental investigation of titanium nanofluids on heat pipe thermal efficiency”, international communications in heat and mass transfer 35 (2008), 1316–1319. [14] peterson g.p., “an introduction to heat pipes: modeling”, testing, and applications, john wiley & sons, new york, 1994. [15] rashidian b., amidpour m. and jafari nasr m. r., “modeling the transient response of the thermosyphon heat pipes”, proceedings of the world congress on engineering, vol. ii, london, u.k., 2008. [16] reay d. and kew p., heat pipes: theory, design and applications, fifth edition,elsevier, 2006. cleary m., grimes r., hodes m. and north m. t., “design of a variable conductance heat pipe for a photonic component”, proceedings of imece2006 , chicago, usa, 2006. [17] shafahi m., bianco v., vafai k. and manca o., “an investigation of the thermal performance of cylindrical heat pipes using nanofluids”, international journal of heat and mass transfer 53 (2010) 376–383. [18] shahi m., mahmoudi a.h. and talebi f., “numerical simulation of steady natural convection heat transfer in a 3-dimensional single-ended tube subjected to a nanofluid”, international journal of heat and mass transfer 37 (2010) 1535–1545. [19] solomon a. b., ramachandran k., pillai b.c., “thermal performance of a heat pipe with nanoparticles coated wick”, applied thermal engineering 36 (2012) 106-112. [20] sreenivasa t. n., sridhara s.n. and pundarika g., “working fluid inventory in miniature heat pipe”, proceedings of the international conference on mechanical engineering, dhaka, bangladesh, 2005. [21] tsai c.y., chein h.t., ding p.p., chan b., luh t.y. and chen p.h., “effect of structural character of gold nanoparticles in nanofluid on heat pipe thermal performance”. materials letters. 58 (2004), 1461–1465. [22] wang p.y., chen x.j., liu z.h., liu y.p., “application of nanofluid in an inclined mesh wicked heat pipes”, thermochimica acta (2012) 1-36. [23] zhu n. and vafai k., “analysis of cylindrical heat pipes incorporating the effects of liquid– vapor coupling and non-darcian transport–a closed form solution”, international journal of heat and mass transfer 42 (1999) 3405–3418. http://dx.doi.org/10.1016/j.applthermaleng.2011.12.004 http://dx.doi.org/10.1016/j.applthermaleng.2011.12.004 al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 table 1: heat pipe specification. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ heat pipe container material copper wall thickness 0.85mm outer diameter 19.05mm heat pipe length 555mm evaporator length 150mm condenser length 97mm working fluid di water and al2o3 nanofluid sink temperature 22 o c set temperature 100 o c ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ yes no print final solve equations of 𝑃 in vapour region and wick structure solve equations of 𝜃 in vapour, wick and wall region decide whether solution has solve equations of ѱ and 𝜔 in liquid region grid generation start field iteration sweep solve equations of 𝑢 and 𝑣 velocities solve equations of ѱ and 𝜔 in vapour region initial dependent variable input data start end figure 2: flow chart for the current computer program. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 3: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=10 w and φ=0. figure 4: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=10 w and φ=0.01. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 5: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=10 w and φ=0.03. figure 6: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=10 w and φ=0.05. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 7: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=20 w and φ=0. figure 8: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=20 w and φ=0.01. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 9: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=20 w and φ=0.03. figure 10: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=20 w and φ=0.05. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 11: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=30 w and φ=0. figure 12: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=30 w and φ=0.01. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 13: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=30 w and φ=0.03. figure 14: dimensionless liquid pressure and stream line distribution inside the heat pipe at qin=30 w and φ=0.05. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 334 figure 15: effect of particle concentration levels on the thermal performance of a heat pipe under various heat input. figure 16: the effect of nanoparticles concentration levels on the maximum heat transfer limit and capillary pressure of the heat pipe. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 333 figure 17: the effect of different nanoparticle concentration levels on the heat pipe thermal resistance. figure 18: comparing current model with available numerical data. 0 5 10 15 20 25 30 35 40 45 50 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 t ( o c ) npc do et al. present work vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 369 nonlinear visco-hyperelastic constitutive modeling for filled elastomeric materials dr. mohsin noori hamzah machines & equipment engineering department university of technology, iraq dr.mohsin@uotechnology.edu.iq asia abdulsattar razaq mechanical engineering department al-qadisiyah university, iraq asiarazak@yahoo.com abstract the mechanical behavior of filled elastomeric materials (rubber or rubber-like materials) is known to be incompressible, or nearly-incompressible, hyperelastic and time-dependent, or viscoelastic. this complex behavior of rubbery materials needs more understanding, and a good knowledge is required for such behavior in order to attain a constitutive modeling for better design of a rubber component for a specific application. to achieve this objective, theoretical and experimental works are presented in this paper. theoretical works are considered for modeling the hyperelastic and viscoelastic behaviors of rubber. the hyperelastic behavior is modeled using mooney–rivlin constitutive model. while the time-dependent behavior (viscoelasticity) was modeled by using prony series. modeling and parameters identification, for both hyperelastic and viscoelastic behaviors, were performed and compared with ansys 14. to do this, different tests were performed on filled rubber in the present work, all tests were performed on filled rubber material with three different kinds of carbon black, n326, n375, and n660 at room temperature. tensile stress-stretch curves were generated from the test data at strain rates 10 mm/min. relaxation stress-time curves were generated from the test data at mean strain (200%) from the effective length of the specimen, at constant strain rate (200 mm/min). from the work it is found that a two-term mooney-riviln adequately describes the hyperelasticity of the material. the numerical results, using ansys, exhibit good agreement with experimental data. key words: elastomer, rubber, rubber-like, constitutive model, carbon black, finite element. المدعمة اللزجة للمواد المطاطية النمذجة الالخطية المفرطة المرونة الخالصة التصرف الميكانيكي للمواد المطاطية (المطاط والمواد الشبيهة به ) المدعمة يعرف على انه غير قابل لالنضغاط , او قريب والمعرفة د على الوقت , او مرن لزج . هذا التصرف المعقد للمواد المطاطية يحتاج فهم اكثر , مالمرونة , يعت مفرطمن ذلك , mailto:dr.mohsin@uotechnology.edu.iq vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 370 العديد حصول على نمذجة لتصميم افضل تركيبة مطاط لتطبيق معين . وللوصول الى هذا الهدف , الجيدة لهذا التصرف يمكن من ال . من االعمال النظرية والعملية قدمت في هذا البحث تم نمذجة تصرف المرونة المرونة والتصرف المرن اللزج للمطاط . لمفرطاالعمال النظرية شملت نمذجة التصرف ا معامالتها التعريفية والنمذجة ريفلن . بينما التصرف المرن اللزج نمذج باستخدام متسلسلة بروني . -مونيالمفرطة باستخدام نموذج ولعمل ذلك , العديد من االختبارات اجريت على . 14مع االنسز تم عمله ومقارنته لكال التصرفين المفرط المرونة والمرن اللزج ات اجريت على مادة المطاط المدعم بثالث انواع مختلفة من اسود الكاربون المطاط المدعم في هذا العمل , جميع االختبار )326n,375n,660n . بدرجة حرارة الغرفة ( .min mm̸10 انات التي تم الحصول عليها من اختبار الشد عند معدل انفعاليمن الب أتاالستطالة انش –االجهاد اتمنحني %) من 200الزمن ) انشأت من البيانات التي تم الحصول عليها عند مستوى انفعال ( –منحنيات اختبار االستراحة ( االجهاد ) . min mm̸ 200الطول الفعال للعينة , عند معدل انفعال ثابت ( مواد المطاطية. النتائج الحسابية ريفلن ذو الثابتين تكون كافية لوصف المرونة العالية لل-من العمل وجد انه موديل موني باستخدام برنامج االنسز يظهر نتائج مطابقة مع النتائج العملية. 1. introduction elastomers involve natural and synthetic rubbers, which are amorphous and are comprised of long molecular chains. chains are highly twisted, coiled, and randomly oriented in an undeformed state. in applying load, these chains become partially straightened and untwisted; when load is removed the chains revert back to its original configuration. their stress-strain relationship can be highly nonlinear. the accurate modeling of this phenomenon is a key issue for a better understanding of the mechanical behavior of rubber. most of the starting point for modeling of various kinds of elastomers is a strain energy function. the properties of a material are described by a constitutive model. generally, this is a mathematical relation between the stress and the strain. as the stress, in some materials, is dependent on other factors rather than the strain, like strain rate, magnitude of strain, temperature, plasticity and strain amplitude and frequency in a case of cyclic loading, so rubber is a material which is dependent on most of the mentioned factors. therefor; there are different kinds of constitutive models, which can be used to model rubber, have been developed. constitutive model is mathematical relation between the stress and the strain to find the material parameters. there are different kinds of constitutive models which can be used to model a rubber. the first successful model was due to kuhn in (1936) [1], who derived a relation between the elastic modulus and the molecular weight of the chains. flory and rehner [2] proposed a four chain regular tetrahedron model. the earliest work of large elastic deformation is due to mooney theory [3], which, then developed by rivlin and called mooney-rivlin model. rivlin [4] showed that mooney-rivlin model, the earlier result of mooney [3], can actually put in most general form by putting the strain energy function in terms of 𝐼1 and 𝐼2(the strain invariants). an important development was introduced by rivlin and saunders [5], who adopted the more logical procedure of choosing the conjugate values of 𝜆1 and 𝜆2 (principle stretch)in the biaxial strain experiment in such a way that in any given test one of the two strain invariants 𝐼1 and 𝐼2 was held constant while the other was varied. a number of scientists, who examined the reinforcement phenomenon (alexandrov and lazurkin [6], dannenberg [7], rigbi [8], medalia [9], edwards [10], kilian et al. [11], leblanc vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 371 [12], kaliske and rothert [13], attributed it to the surface mobility and dragged slippage of adsorbed segments of elastomer chains over the surface of filler particles, assuming that this process prevented molecules from premature breaking and thus increased the resistance of material to extension. another phenomenon was observed in elastomer behavior when it is subjected to cyclic loading which is characterized by an important loss of stiffness or a stress softening during the first few cycles. bouasse and carriere in (1903) first found this phenomenon in a test for a rubber vulcanized [14]. as a consequence of a more extensive experimental investigation by mullins in (1947), the stress softening effect is now widely known as the mullins effect. lion [15], septanika [16], miehe and keck [17], drozdov and dorfmann [18] and besdo and ihlemann [19] made their contributions to this field. the main objective of the present paper is, first, considering hyperelastic constitutive modeling for filled rubber using mooney–rivlin, followed by examination of a viscoelastic constitutive model using prony series. the two are then combined to yield a visco-hyperelastic constitutive relationship for rubber materials loaded at different strain rates. the modeling and parameters identification will be implemented in ansys 14. 2. experimental work 2.1 materials and sample preparation the materials and samples preparing processes were done in babylon tire factory laboratories. the gum material and additives were performed using the calendering machine, the mixing process continues till reaching a homogenous blend. the sulfur and accelerators are added at the end of the mixing process to avoid curing during calendaring processes. electrical piston was used to cure the blend, when the piston temperature reach (145ϲ°) the (70 gr) from the blend, (table 1), pressed by mold for (45 min) to produce a thin sheet of rubber which can be used later to make the dumbbell specimen. (table 1) shows the blend with carbon black n375, the two other recipes are the same but with carbon black n326 and n660. dumbbell specimens were manufactured under astm d412 specifications for tensile test as shown in (figure 1). 2.2 tensile tests these tests have been carried out by using the instrument showing in (figure 2) type monsanto tensometor 10. to starting the test the instrument must be fed by input data, thickness, width and the strain rate (10 mm/min). the samples stretched to 300% from the original length which means (λ=3). the experiment has been repeated for all three blends. the recorded values were used later to draw the stress-stretch curve, as shown in (figure 3). 2.3 stress relaxation test rubbers are classified as viscoelastic materials, viscoelastic materials appear both elastic solid and a viscous fluid response when deformed. the main important method to study and compare the viscoelastic compounds properties is stress relaxation experiment method. stress relaxation can be defined as continued decreasing in stress needed to maintain a given deformation or loss of stiffness with time. this test has been carried out by using monsanto tensometor 10 instrument vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 372 showed in (figure 2) which the same instrument used in tensile test before. dumbbell specimen used in the relaxation test is shown in (figure 1). the procedure started by holding both ends of the sample via clamps of the instrument. as in tensile test the effective length of the sample is the distance between the two holders which fixed at length (25 mm), then fed the instrument by input data which like, thickness, width of the sample and strain rate. strain rate was fixed at 200mm/min for all experiment duration. after completing all those steps, the tensile stress was applied and continued till the deformation reached 200% and then stopped. the decreasing in stress was recorded by using video camera. the period of recording the data were continued for 5 minutes and the values taken were used for drawing the relationship between time and stress. same steps were repeated for each blend used in this work. (figure 4) show the relationship between stress and time for different blends at 200% deformation which represent the relaxation phenomena. 3. constitutive model the properties of a material are described by a constitutive model. generally, this is a mathematical relation between the stress and the strain. as the stress, in some materials, is dependent on other factors rather than the strain, like strain rate, magnitude of strain, temperature, plasticity and strain amplitude and frequency in a case of cyclic loading, so rubber is a material which is dependent on most of the mentioned factors. therefore; there are different kinds of constitutive models, which can be used to model rubber, have been developed. the purpose of the constitutive theories is to develop mathematical models for representing the actual behavior of matter. past researches developed two approaches to obtain the strain energy functions in rubbery materials, or generally, elastomers. the first approach is based on the statistical thermodynamic, where the microscopic molecular structure of the material is taken into account. the second is a phenomenological one, which treats the material as a continuum. 3.1 mooney-rivlin constitutive model the big challenge in non-linear elasticity theory is to come up with a reasonable and applicable elastic law (strain energy function), which is the crucial step to the development of dependable analysis tools. despite of many attempts have been made to develop a theoretical stress-strain relation that can match the experimental results for hyperelastic materials, mooney's theory was the most significant phenomenological theory of large elastic deformations, which has played a principal part in all later work in the field. the compressible form of mooney-rivlin material model is [5] 𝑊 = 𝑐10(ī1 − 3) + 𝑐01(ī2 − 3) + 1 2 𝐾(𝐽 − 1)2 (1) where the third term is a compressible part, and 𝐽 is the determinant of deformation gradient (or volume ratio). for incompressible material, 𝐽 = 1 for that mooney-rivlin equation can be written as. 𝑊 = 𝑐10(𝐼1 − 3) + 𝑐01(𝐼2 − 3) (2) where w is the strain energy function, 𝛪1 = 𝜆12 + 𝜆22 + 𝜆32 , 𝛪2 = 𝜆12𝜆22 + 𝜆22𝜆32 + 𝜆32𝜆12, 𝑐01 and 𝑐10 are material constants, and 𝜆1, 𝜆2 and 𝜆3 are the principle stretches. in the tensile test (the case of uniaxial tension), the change in strain energy can be expressed in variational form as: vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 373 𝑑𝑊 = �𝜕𝑊 𝜕𝜆1 �𝑑𝜆1 (3) which leads to the following form of mooney-rivlin constitutive relation: 𝜎𝑜 = 2 �𝜆2 − 1 𝜆 ��𝑐10 + 𝑐01 𝜆 � (4) where 𝜎𝑜 represents the engineering stress. in this case the cross sectional area changes with the deformation and can be expressed as [20]: 𝐴 = 𝐴0 𝜆 (5) by substitute equation (4) in equation (5), cauchy true stresses obtained as: 𝜎 = 2𝑐10 �𝜆 − 1 𝜆2 � + 2𝑐01 �1 − 1 𝜆2 � (6) equation (6) can be solved by using the least squares (linear regression) approach, the constitutive model coefficient obtained as: 𝑌 = 𝑐10 + 𝑐01𝑋 (7) where 𝑌 = 𝜎 2(𝜆−𝜆−2) and 𝑋 = 1 𝜆 . solving the above equation to find the coefficient as: c10n + c01 ∑ x = ∑ y c10 ∑ x + c01 ∑ x2 = ∑ xy (8) 3.2 viscoelastic model one of the basic rheological viscoelastic models which can anticipate relaxation behavior was proposed by james clark maxwell, maxwell model, which consists of viscous newtonian damper and elastic hookian spring in series. the total strain would be equal to the summation of the strain in elastic and viscous elements, because they are in series. in relaxation test when the displacement applying instantaneously, the viscous part needs some time to move, while the spring could move instantaneously. the whole displacement will be compensated by the spring at the time zero. as the time goes on, the displacement in the spring will decrease, but increase in the damper. for infinity time, the strain in the elastic part would be zero, but this is a problem in modeling complicated elastomers, that is stress in these materials even in the long time would not lead to zero. thus, a general maxwell model for modeling relaxation behavior is needed. when the material is assumed to be a general maxwell solid, the relaxation function is typically modeled with a prony series. values of the shear and bulk modulus would be enough as the starting values of the material properties over the time, which are representative of deviatoric and volumetric parts of the stress, respectively, as expressed in the following equations [21]: 𝜎 = 𝜎𝑑𝑒𝑣𝑖𝑎𝑡𝑜𝑟𝑖𝑐 + 𝜎𝑣𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐 , (9) 𝜎 = ∫ 2𝐺(𝑡 − 𝜏) 𝑑𝑒 𝑑𝜏 𝑑𝜏 𝑡 0 + 𝑰∫ 𝐾(𝑡 − 𝜏) 𝑑∆ 𝑑𝜏 𝑑𝜏 𝑡 0 , (10) where 𝜎 is cauchy stress, e and ∆ are deviatoric parts of the strains, g(t) and k(t) are shear and bulk modulus functions, respectively, t and τ are current and past time, respectively, and i is identity matrix. relating to the shear and bulk modulus over the time, prony series can be proposed by the flowing formulas [21]: vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 374 𝐺 = 𝐺0 �𝛼∞𝐺 + ∑ 𝛼𝑖 𝐺𝑛𝐺 𝑖=1 𝑒𝑥𝑝�− 𝑡 𝜏𝑖 𝐺�� (11) 𝐾 = 𝐾0 �𝛼∞𝐾 + ∑ 𝛼𝑖 𝐾𝑛𝐾 𝑖=1 𝑒𝑥𝑝�− 𝑡 𝜏𝑖 𝐾�� (12) where superscript shows belonging to shear or bulk modulus, and subscript indices the number of series component, 𝛼𝑖 = 𝐺𝑖 𝐺0 and 𝜏𝑖 are relaxation time constants for each prony series component. 𝛼𝑖 that can be calculated at t equal to zero will be obtained from equation (11), by writing the equation as 𝐺0 = 𝐺0�𝛼∞𝐺 + ∑ 𝛼𝑖 𝐺𝑛𝐺 𝑖=1 � (13) it means that 𝛼∞ = 1 − ∑ 𝛼𝑖 𝑛 𝑖=1 , so equation (11) can be written as : 1 = 𝛼∞ + ∑ 𝛼𝑖 𝑛 𝑖=1 , there are only two constants 𝛼𝑖 and 𝜏𝑖 which should be determined by a relaxation test. in the series, the initial values of g and k would be taken into account at time equal to zero. for finding the coefficient of the bulk function, the same above procedure will be followed. 4. results and discussion 4.1 fitting hyperelastic material parameters in ansys in this research, stress-strain data obtained from the tensile test were used to determine the material parameters in hyperelastic models which in turn employed in the commercial fea software ansys 14.0 to perform structural simulations of rubber components submitted to quasistatic loading under hyperelastic deformations. there are some key assumptions related to the hyperelastic constitutive models in ansys, deformations are fully recoverable, thermal expansion is isotropic, materials nearly or fully incompressible and the constitutive hyperelastic models are defined through a strain energy density function. ansys provides curve fitting tools to obtain material constants for hyperelastic models from the results obtained during the test. these results are fed into the ansys software in the form of a text file for defined stress-strain of the manipulated testing data for uniaxial tension. immediately after the data given to the ansys, the fitting process starts by choosing the mooney-rivlin strain energy function with two parameters. based on above procedure, ansys analyzes the data, and the materials constants 𝐶10 and 𝐶01 become known under quasi-static strain rate (10 mm/min). these constants for the three blends used in the present work are presented (table 2). (figure 5) shows the experimental stresses vs. strains for the three rubber blends used in the current work and compared with that obtained from ansys 14 using the above mentioned fitting procedure for mooney-rivlin constitutive model. the results were very encouraging, since the ansys model was accurate for the approximately 75% range of deflections. (tables 3) summarizes the accuracy achieved in the fea model of the dumbbell specimen of tensile test experiments with the adjusted mooney-rivlin function. the predicted stress at different strains and at strain rate 10 mm/min is relatively well compared to test data. the most minimum strain rate considered as equilibriums state in this case, so it is the minimum error ratio. vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 375 4.2 fitting relaxation tests of prony series using ansys the viscoelastic behavior for elastomer in consideration was studied under stress relaxation test by using stress vs. time curve obtained from the test, the curve which considered being as a milestone for further steps. the shear modulus, g, may be calculated experimentally using the following equation [21]: 𝐺 = 𝐸 2(1+𝑣) (14) the instantaneous modulus of elasticity, e, in the above equation, can be calculated by dividing the stress over the strain at a specific time t. the repetitive calculation is facilitated by the use of ms excel. the final results of the shear modulus and time values obtained from above procedure were saved as a text file. in ansys by having shear modulus over time, optimal parameters fitting of prony series for shear could be found. the implemented materials were two components of the prony series for modeling hyperelastic materials, (table 4) shows the constants prony obtained from ansys. the curve for shear modulus vs. time are plotted for the relaxation test conducted in the lab and compared with the results of the ansys model for three blends, as shown in (figure 6). 4.3 rubber sheet with central hole to validate the current analysis a cyclic tension was applied on rubber sheet with a central hole, as shown in (figure 7a). the sheet manufactured from blend with carbon black n326, its dimensions are: 15cm long, 7.5cm wide, and ~0.25cm thick, the hole at the center is 2.6cm diameter. two of clamps were made from steel plate fixed by three screws for each end. purposes of using these clamps are to distribute the force evenly on the both ends of the specimen and to make it easy to be fixed between the two jaws of the computerized test machine, testometric ax m500-25kn, as shown in (figure 7b). the test was carried out under strain rate of 100mm/min and deformation 100% with two numbers of cycles. the results of the test are plotted in (figure 8). it is seen from (figure 8) that rubber material exhibit hysteresis during cyclic loading, this indicates that the material has a significant amount of viscous behavior, and as the viscoelastic response of the materials increases the amount of hysteresis will increases. that is related to its time dependent characterizes behavior and for the same reason noticed that the uploading (increase the load) condition seemed stiffer than the unloading (decreasing the load) condition, this is an interesting behaviour and may the material relaxed during the unloading condition. also, there is a significant difference between the response during the cycle one and cycle two during uploading, see (figure 8), while, in the unloading condition the response is less sensitive during the first two cycles. this feature significant clearly in filled rubber as used in this research, to broken the bonds between filled materials (carbon black) in the first cycle for the same strain rate. this problem is solved by ansys, the model meshed with element type hyperelastic 8 nodes 183. the boundary conditions were applied as follows. the bottom edge of the model was fixed, while the upper edge is given a displacement values that makes the strain, first, 50%, and then 100% of strains. (figure 9) showed the von misses stress contours with the exact deformed mesh at these strains. observe that the inhomogeneous deformation is concentrated in the neighborhood of the hole, this localization gives a stress concentration at the sides of the hole, which is as expected in metallic solid materials, and the only difference here is that due to high deformation characteristics of the rubbery materials the stress concentration factor is lower. vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 376 5. conclusion 1by employing a fundamental approach to the formulation of constitutive relationships, a mooney-rivlin constitutive model with prony series are anticipated to describe viscohyperelastic large deformation behaviour of incompressible rubber-like materials under different strain rates. 2it is found that a two-term mooney-rivlin adequately describes the hyperelasticity of the material. another component in the equation, a generalised maxwell model, is introduced to characterise viscoelastic response under these strain rates. 3the total expression corresponds to a hyperelastic solid in parallel with a generalized maxwell model, thus characterising not only hyperelasticity but also strain rate and strain history dependent viscoelasticity. 4stress vs. strain curves predicted by the model for three kinds of rubber blends are compared with the experimental data performed in the current research. the comparisons showed that the proposed model is well-suited for the description of visco-hyperelastic behaviour of rubber-like materials loaded at different strain rates. 5the numerical results, using ansys, exhibit good agreement with experimental data, demonstrating that the model is suitable for prediction of visco-hyperelastic behaviour in situations different from that used to determine its parameters. references [1] james h. m. and guth e.,”theory of the elastic properties of rubber”, journal of chemical physics/ volume 11/ issue 10, 1943. 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[14] de tommasi d., and puglisi g.,” a micromechanics-based model for the mullins effect”, doi: 10.1122/1.220670, 2006 [15] lion a. , ”a constitutive model for carbon black filled rubber: experimental investigations and mathematical representation” continuum mechanics and thermodynamics 8, pp.153-169, 1996. [16] septanika e g. , ”a time-dependent constitutive model for filled and vulcanised rubbers” phd thesis, delft university of technology, the netherlands, 1998. [17] miehe c., and keck j.,”superimposed finite elastic–viscoelastic–plastoelastic stress response with damage in filled rubbery polymers. experiments, modelling and algorithmic implementation”, journal of the mechanics and physics of solids 48, pp. 323-365, 2000 [18] drozdov a.d., and dorfmann a.,” stress-strain relations in finite viscoelastoplasticity of rigid-rod networks: applications to the mullins effect” continuum mechanics and thermodynamics 13, pp. 183-205, 2001. [19] besdo d., and ihlemann j. , ”a phonological constitutive model for rubberlike materials and its numerical applications”, international journal of plasticity 19, pp. 1019-1036, 2003. [20] dargazany r., itskov m., and liu j.,” microstructural changes of filled rubber-like materials under cyclic loading”, pamm _ proc. appl. math. mech. 10, pp. 289 – 290, 2010. [21] mottahedia m., dadalaub a., andhaflac a.,” numerical analysis of relaxation test based on prony series material model”, seidenstraße 36, 70174 stuttgart/ germany, 2010. vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 378 table 1: the recipe of the blend used in tread of farm tire quantity in gm phr* sbr 1502(strene butadien rubber) 85.5 100 sbr 1712(strene butadien rubber) 142.5 br cis(polybutadiene) 56.4 zno(zinc oxide) 7.2 2.53 stearic acid 4.2 1.47 6ppd(protection product) 5.7 2 tmq 3 1.05 wax 5.7 2 paraffin oil 56.7 19.93 sulfur 4.5 1.58 mbs(morpholinothiobenzothiazole accelerators) 3 1.05 carbon black n375 183.6 64.55 reclaimed rubber 42 14.76 * parts per hundred rubbers table 2: materials parameters obtained using ansys 14. blend with different carbon blacks mooney-rivlin coefficients c10 c01 n326 0.598750473900 -0.969581769171 n375 0.797369060278 -1.384107044970 n660 0.783195721870 -1.421800766730 table 3: comparison of stresses at different strains between the experimental test and ansys. strain % stresses at specific strains (mpa) error % experimental predicted (ansys) blend with n326 100 1.530 1.567 2.410 200 3.140 2.800 10.82 blend with n375 100 1.809 1.859 2.760 200 4.028 3.530 12.36 blend with n660 100 1.650 1.712 3.750 200 4.000 3.370 15.75 vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 379 table 4: prony series constants for three blends obtained from ansys. prony series constants kind of blend blend with carbon black n326 blend with carbon black n375 blend with carbon black n660 𝛼0 𝐺 0.907663954342 1.049103209860 1.127357967550 𝛼1 𝐺 0.339863017171 0.445172377449 0.437216238454 𝛼2 𝐺 0.354166922530 0.463290662996 0.405809181564 𝜏1 96.15047225200 0.009380944487 46.29573533270 𝜏2 13.31736723090 56.54316636330 0.286361264090 figure 1: dumbbell type rubber specimens. figure 2: tensile test instrument, monsanto tensometor 10 vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 380 figure 3: stress-strain relationship for three blends at strain rate 10 mm/min figure 4: stress relaxation for three blends at deformation 200% 0 1 2 3 4 5 1 1.5 2 2.5 3 blend with n375 blend withn326 blend withn660 st re ss stretch, λ 0 1 2 3 4 5 6 7 8 0 0.5 1 1.5 2 2.5 3 3.5 n326 n375 n660 st re ss (m pa ) time (min) vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 381 figure 5: experimental stresses-strains plots for three blends used as compared with ansys. figure 6: plots of the experimental shear moduli vs. time for three blends as compared with ansys. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 st re ss (m pa ) stretch (mm/mm) experimental n326 ansys n326 experimental n375 ansys n375 0.50 0.75 1.00 1.25 1.50 1.e+01 2.e+02 sh ea r m od ul us (m pa ) time (s) experimental n375 ansys n375 experimental n326 ansys n326 vol. 6 no. 4 year 2013 qadisiya journal for engineering sciences -al 382 (a) (b) figure 7: (a) rubber sheet with central hole, (b) cyclic tensile test for rubber sheet specimen with central hole using a computerized testometric ax m500-25kn. figure 8: two cycles for specimen with center hole and carbon black n326 at strain rate 100 mm/min. (a) (b) figure 9: rubber sheet with central hole problem solved by ansys 14, (a) 50% applied final strain, (b) 100% applied final strain. 0 0.5 1 1.5 2 0 20 40 60 80 100 120 st re ss (m pa ) strain (mm/mm) cycle no.1 cycle no.2 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 136 characteristics and compositions of solid waste in nassiriya city ryidh a. yasir zaidun naji abudi thi-qar university al-mustansiryiah university marshes research centre college of engineering abstract: the improving of living condition and increasing of population density growth assist in increase the quantity and quality of domestic solid waste in households in nassiriya city. a samples of solid waste have been collected from households in nassiriya city to know the quantity of solid waste generated. households classified into three zones according to economic status (high, middle and low income levels). samples collected for seven months, from january to july 2008. this paper explains that the generation rate of solid waste for person or capita changes from each income level to another and from month to other and we can represent 0.68 kg/cap./day as average of domestic solid waste generated in present time in city, the quantity of solid waste generated in nassiriya city is equal to 22.15 ton/day this only for domestic waste (solid waste from commercial, industrial and medical waste not reported in this paper). value of density was calculated is equal to 275.33 kg/m 3 , the percent of each individual component for solid waste components also calculated and for seven months for each income level. these percent shows that the most common components is organic (food) waste which is participle and its percent in range of (61.88 % to 69.95 %) and these value is similar with other results in other cities of iraq. the compressive of results of this paper with other results shows its similar to iraqi cities and differs to europe united cities. keyword: solid waste management, waste composition and characteristics, nassiriya city �$ � ا� �)�$� '8 �� اص و �آ��ت ا� &�$�ت ا��.# � �� ���� *��� +���� ���� ����$ ��, +%"��� %��(� ��� %"����� ����.� &���� $��� % ����� %�!� /! ��� �������� � ���� ������ ����� ����� ����� �� ���� ������� ������ ������ ������� ����� ���� ! ������� ����� �� ������� . �� #�$ %� �������� ������ �� &����� � ������� � ��� ������ ���� ������ �� . ������'( ���)� *�� �����(� +���� ,-� *� ������ ��') �/����� ������ 0����� ( 2������� +����� *� &3�� ����4 +����� ������ �/���� . �� ���� �5� � �5� �� � ���� �� ��� ���� � ����� �5�� *� ��� al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 137 6778 . )4�9 �� ��� ! �:� � ��;�� �) �� <3�� �=���� ��� ������ &��� *�! 0�39 �5� �� *�! ��39 %'� ����� ����7.>8 %;� /<3�� / ������� ����� @� � a�b � �4�)� '�� �� ������� ������� &���� %��� ��ا� ����� ������� � ip ا���2زل �٢٢.١٥ /w / ت�f$�(2��24�� وا�fوا� �f$ا ا�2)�$�ت ا����ر�� �$�j�2�2 ا�$� ا���م � �� ا������ة / ا����r)��ت qا��q��>ا��4��وا . ��9 %� �/� � ��� ������ ����� ���' �=��$�! �$�� �5�! c���� 6de.ff %;� /%f � ���� g��) %� ��� �� � ��� &�� ���:�� � ��� ������ ����5�h�� &�� � ��� &���� c������ � �)�( g��) %� ��� �� �� &3�� �:� � �:� &�� ��� . ���:�� g��� �� �'� ! ����� �� �/� ���4�� ������ �= ������� ��:��� � ��� � )� �� ��� �61.88%) *�! 69.95 % (�� #� i ���� � ��� jb=� g�0�3k %� ��� �=��$�! �� ���� �'� ��' ��� . l:��� � ����� �� #� ,) � b= �� �5��� &��)� %� ��� l:���� ����/� %� ���%�'�9� ���� �/ ��� �� ��� � ��$9 �� *�� 0�39 �'� + ��� � �5�9%�/� jb= #� �55 ��� ��)�( �� �� �5�-��� � �5�-�3 � � ��k . introduction: solid waste is any solid material that is disposed of because it has no further use to society in its present form. in more specific terms, the u.s. epa has defined a solid waste as "any discarded material, including solid, liquid, semi-solid, or contained gaseous material resulting from industrial, commercial, mining, agricultural operations and from community activities" ( bishop, 2000). solids wastes are produced wherever man is found farms, mines, stores, offices factories, homes, hospitals, streets, and even the primitive encampments of traditional nomads(rao, 1994). data on the amount, sources and characteristics of refuse in a city should be the basis to the planning, designing and satisfactory operation of solid waste management (storage, collection, transport, and disposal) systems and the application of disposal methods. essential data can be gathered through physical survey. the quantity and quality of solid waste generated may be affected seriously by local conditions (climate, seasons, socioeconomic conditions, income levels, etc.) and the type and activity of the source (kirov, 1975). domestic or households solid waste is managed by the ministry of municipalities and public works . it is necessary to have a detailed study about area land use in any city in order to know the size and quantity of solid waste generated and to determine the way of collecting and treatment it. figure (1) shows the current and suggested use of land in all sectors of the city according to the master plan. it is noticed that the area of land used for residential is about 15.82 km 2 and it represents about 28% from the total area, while the area used for the commercial activities is about 5.٦٥ km 2 and it represents to 10% and it is focused in the old part of the city (old city square). the area of land used for industrial purpose is about (2.61 km 2 ) and represents 4% of the total area of the city, the major industrial activities are: ur state establishment for mechanical industries contains three large industrial (aluminum processing plant. cable plant, wood role plant), nassiriyah textile factory, thi qar oil refinery, thermo power station and the asphalt plant. there is also about 2.6 km 2 and represents 4% from the total area is dedicated for industrial storage, moreover there is an industrial site about 1.3 km 2 and represents 1% form al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 138 the total area and the most workshops of car maintenance and repairing are concentrated in this area, the majority of waste generated in this area are un useful part of cars and scrap. the public services cover about 9.2 km 2 and represents 15% from the total area and there is area concerned with the service sector covers 3.1 km 2 which equal to 7 % of total area. the green areas cover about 6.05 km 2 and this represents 11% form the total area, where the water surface (euphrates river and main out fall drain) covers area of 3.07 km 2 which equal to 5% of total area. the future expanding will be about 7.6 km and that will represent 14% from the total area. scope of work: nassiriyah city the centre of thi qar governorate and it lays on south of iraq at about 360 km south east to baghdad, between 30 ◦ 56˝ to 30 ◦ 59˝ in north and on 46 ◦ 15˝ in east . according to the central census organization (2008), the total population of nassiriyah city is about 472000 person, distributed as (423500 are in urban areas, while 48500 are in the rural areas. the total area of an nassiriyah, according the to master plan, is about 57 km 2 and the total number of houses 48500 house (nassiriyah municipality office). waste collecting processing in nassiriyah city: an nassiryiyah municipality office is responsible for solid waste management (collecting, transportation and disposal) the municipality divided city to seven sector in order to facilitate solid waste management, theses sectors are: 1. the old city square sector: it includes the quarters of tammoz, al sherqiya, al majed, nissan, aledarah el mahaliya and al bashaer. these quarters are among the high income and it includes the commercial center of the city and other governmental offices. 2. al salihiya sector: it includes the quarters of al salihiya, al shuhada and al hussien. 3. al sader sector: it includes the quarters of al sader, al rafidain and ur, this sector covers also the main terminal and many governmental offices. 4. sumer sector : includes the quarters of sumer, al muaalmeen and arido. 5. khalf el sareea sector: it includes the quarters of al zahraa, al tadhiya, al buqaa and al fida’a. 6. al thawra sector: it includes the quarters of al thawra, al mansoriya, baghdad street. al mutanazah, al taqa and al eqtisadiyeen. 7. al shimookh sector: it includes the quarters of shimookh, shuala, iskan qadeem, isakn sinaee and imarat el sakaniya. the headquarter of thi qar university with some colleges and most large industrial plants in addition to the main stadium located in this sector . the main equipments used in solid waste collection are: tractor 4 ton capacity. ordinary truck 2 ton capacity. waste collection truck ( 4 and 8 ton capacity). trolley. waste truck (for bulk transportation). methodology: information about the population, were collected and classified into three groups of income: high, middle and low. three regions were selected to conduct the study on. samples were taken randomly but according to the different socio levels, figure (2) shows the master plan (essential design) for al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 139 nassiriya city including location of sampled areas for low-income, middle-income and highincome level, major dumping / landfill areas and industrial site. random samples were gathered from each region and from the three different income levels (see table (1)) provided samples plastic bags were distributed to the selected households to collect its waste in and number of occupants was recorded. bags are to be collected each the other day and replaced by another; and so on for seven months in each of income level. collection crews transferred the plastic bags of wastes from nominated houses, weighed individually and labeled according to its socio-economic classification. the monthly samples collected from the nominated houses were weighed and randomly mixed, the basic weight was hand sorted into nine individual components making up the two broad categories of combustible and non –combustible as follows: (a) combustibles (i) organic (putrescible): including all wastes from selling, preparation, cooking, and serving food. (ii) paper: all kind of waste paper, newspapers, and cardboard. (iii) plastics: all varieties (iv) textiles and rugs: all textiles, synthetics, wood, leather (v) misc. combustibles (b) non-combustibles (i) tins, cans and metal: ferrous and non-ferrous (ii) glass: non-returnable bottles, soft drink bottles, broken glass, ceramics, ..etc. (iii) cleaning waste : garden waste, dust ,etc. the refuse density was calculated by dividing the total refuse weight by the bulk volume of the refuse. results: 1 waste generation rate: generation rate is represent quantity of wastes as a function of volume or weight. most studies used weight as a function of generation rate because it was not effected by compaction in transfer process. generation rate is very important to design a system of solid waste management and is effected by many local factors, including time of year, habits, education, economic status of the people, and location. figures (3, 4) show solid waste generation rates and density in nassiriya city obtained in this paper for seven months. from figures (5, 6) average solid waste generation rates and density were calculate as (0.70 kg/capita/day, 293 kg/m 3 ), (0.72 kg/capita/day, 249 kg/m 3 ), and (0.63 kg/capita/day, 284 kg/m 3 ) for high, middle, and low income levels respectively. average solid waste generation rate and density for all city were (0.68 kg/capita/day, 275.33 kg/m 3 ), total solid waste generation for nassiriya city was (221467.7 kg/day). quantities of solid wastes vary considerably in composition and quantity depending on the economic status and ethnic composition. quantities also vary with seasons, horticultural choices, and geographical characteristics of land, rainfall, climate, and habits of people: what they eat, drink and the packaged materials they buy. variations also depend on the availability of fresh fruits and vegetables. residents of large cities and towns tend to throw away more than residents of small towns and villages do (ceha, 1995). there is considerable confusion on generation rates of solid waste. this is because of the different methods of measurement and different waste classification adopted for reporting data. the reason for measuring generation rates is to obtain data that can be used to determine al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 140 the total amount of wastes to be measured. therefore, in any solid waste management study, extreme care must be exercised in allocating funds and deciding what actually needs to be known. the value of generation rate in summer season higher than it in winter season, the reason for this summer in iraq increasing in production food spatially vegetables and fruits . different generation rates were obtained through studies carried out in some iraqi governorates at different time of the year. generation rates varied from 0.35 kg/capita/day for faluja city (al-jumaily, 1998) to 0.420 kg/capita/d. for najaf (hamoud, 2005) to 0.7 kg/c/day for baghdad (qasir, 1978). table (2) shows a clear comparison in solid waste generation rates throughout the iraqi governorates. 2 density: knowledge of this property of waste is needed for any transportation or dumping operation. also of importance is the trend for the bulk density to decrease with the growing proportion of paper and plastics in refuse. the relationship between bulk density and applied load is of special interest to municipal authorities due to the increasing use of compaction vehicles to collect domestic waste (kirov, 1975). density (d) was measured by using a cylindrical container of 0.0185 m 3 volume (v). the container was filled by the shovel; with out compressing it, the container was rocked back and forth for several times during filling then weighed of it (w) to find the density of the wastes using the equation (1): d = w / v (1) data of density were drawn in the figures (4, 6) for each income level, the average density of the different income levels varied between (232) and (335) kg/m 3 for low-income level, and between (215) and (281) kg/m 3 for middle-income level, and between (243) and (368) kg/m 3 for high-income level, while the highest average density value that is (368) kg/m 3 for high income level in january month. table (3) show a comparison of the average densities for cities in iraq with values of density appears in this paper. 3 waste composition: unfortunately, information regarding the composition of the urban wastes in iraq is not generally available, as the municipalities do not carry out regular analysis. in fact, wastes are very heterogeneous in composition, and the geographical, temporal, and seasonal variations in its composition make it difficult to define a "typical waste". however, there are some studies carried out in some governorates through out of iraq at different time of the year. as for example, al-najar (al-najar, 1998) indicated an organic content of 63%, and a waste density of 469 kg/m 3 . hamoud (hamoud, 2005) indicated an organic content of 69.03% in al-najaf city, while al-jumaily (al-jumaily, 1998) declared that the most common category in the composition of faluja municipal waste is the food waste (70.6) %. in this paper from data shown in figures (7, 8, 9, 10, 11, and 12) concluded that the most common category in the composition of municipal waste is the food waste the range of it varies from (61.88%) in high income in dry season to 69.95 % in high income in wet season also we show that the percent of organic waste in the wet season is higher than its percent in dry season because of increasing the value of moisture content in waste in wet season. the range of percentage of plastic waste is varies from 4.36% in low income in wet season to 10.68 % in high income in wet season the reason of this variation in wet season using of juice and drinking which put in the plastic material in additional to the socio and economical condition. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 141 average value of percent for metal waste appear a few difference from season to season for the three income level (5.3, 4.44 and 4.77) for high, middle and low income level respectively in wet season, while in dry season its percent was (4.96, 4.76 and 4.60) respectively the reason of this all people in different income level using matter covered with a metal cover in both two seasons. percentage of glass waste is (3.41, 3.81 and 5.21) in wet season where in dry season the values of percentage are (4.93,4.75 and 5.12) for each income level respectively. for paper waste the percent is (5.16, 3.85 and 4.57 ) in wet season, in dry season (5.22, 5.04 and 4.27) respectively for each income level. the percent of rapper and combustibles waste is in range of (0.79 to 2.24), the average percent of textile waste is varies from (2.27 %) in high income level to 3.25% in low income level in wet season, in dry season it varies from 2.72 in low income level to 3.98 % in high income level). incombustible waste contains cleaning waste, garden waste, dust, etc. the percent of these waste is (5.65, 5.01 and 4.54) in wet season, in dry season (6.34, 7.73 and 6.83 %) for each income level, the values of these waste in dry season is more than its values in wet season because increasing the sand storm in summer season in nassiriya city. table (4) gives the composition of wastes in some governorate of iraq and a comparison is made with the urban solid waste from a typical european cities. as is seen in table (4) average paper contents in iraq cities is about 3 to 5 percent as compared with about 27 percent for a typical european cities. it has been found that as the personal income rises, kitchen wastes decline but the paper, metals and glass wastes increase; the total weight generated rises but the density of the wastes decline (rao, 1994). conclusions: 1. the average daily waste generated in nassiriya city was 0.68 kg/capita, where the average value of density is 275.33 kg/m 3 and it is similar to the other values of densities in other iraq cities. 2. the total yearly solid waste generated in nassiriya is approach to 8063 ton/year. 3. the largest component of solid waste generated in nassiriya household is the food wastes (70.18%), plastic (6.75%), metal (3.55%), glass (3.95%), paper (3.42%), rubber (0.24%), textile (0.89%), miscell. (2.54%), and unmiscell. (garden waste) (3.89%). 4. the solid waste generated in nassiriya influced with the economic statues. the amount of solid waste generated in high income was (37.57 ton/day), while in the low income was (79.75 ton/day). references: 1. al-jumaily, suhaib khalid "study and evaluation of solid waste collection and disposal system at fluja city and its environmental influences on the area" a thesis submitted to the college of engineering of the university of baghdad for the master of science in environment eng., (1998). 2. al-najar, waleed muhammad selman,"a study of collection and treatment of solid waste for kurkuk city and its environmental impact" a thesis submitted to the college of engineering of the university of baghdad for the master of science in environment eng., (1998) 3. bishop, paual l. "pollution prevention: fundamentals and practice" mcgraw-hill international editions, 2000. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 142 4. ceha, "solid waste management in some countries of eastern mediterranean region" ceha, amman, jordan, 1995 5. dheyaa, etc, "characteristics and compositions of solid waste in baghdad", second international symposium on energy from biomass and waste, venice , italy, 2008. 6. environmental management in developing countries "waste management" institute for scientific co-operation , tubingen . volume 2 1995. 7. hamoud, hussein abdul muttalib, "assessment and development of solid wastes management in al-najaf city" a thesis submitted to the college of engineering of the university of baghdad for the master of science in environment eng., (2005). 8. kirov, y. nikcolas, "principles of waste management –unit operations and process" kingsway printers pty ltd, 1975 9. qasir, anwar jamil buni, "refuse disposal of baghdad city" a thesis submitted to the college of engineering of the university of baghdad for the master of science in civil eng., (1978). 10. rao, c,s, "environmental pollution control engineering" wiley eastern limited , 1994. 11. youseif, w. fwezi "management, and disposal of almosul solid waste" a thesis submitted to the college of engineering of the university of al-mosul for the master of science in civil eng., (1988). table (1) social properties of households of sampling low mid high min. avg max. min. avg max. min. avg max. income level properties 3 6 11 3 7 16 3 7 14 household size, person 25 25 15 total number of households of sampling 135 182 100 total person in households of sampling al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 143 table (2) generation rates in some iraqi governorates including the recent study results gov./city mosul (youseif, 1988) baghdad (dheyaa, 2008) kirkuk (al-najar, 1998) najaf (hamoud, 2005) faluja (al-jumaily, 1998) nassiriya gen. rate kg/capita/d 0.54 1.11 0.44 0.42 0.32 0.68 year 1988 2002 1998 2004 2005 2008 table (3) density value of solid waste in some iraqi governorates city/stat e mosul (youseif, 1988) kirkuk (al-najar, 1998) baghdad (qasir, 1978) najaf (hamoud , 2005) faluja (al-jumaily, 1998) nassiriya density )(kg/m 3 280 469 445 473 462.5 275.3 year 1988 1998 1977 2004 2005 2008 table (4) components of municipal solid waste as weight percent in some governorates in iraq and typical european city comp. baghdad mosul kirkuk faluja najaf nassiriya typical europe. putrescible (food) 69.6 81.0 67.5 70.6 69.03 70.18 30 plastic 5.3 3.0 6.33 8.1 5.09 6.75 3 metal 2.2 5.4 8.40 1.3 7.09 3.55 7 glass 2.2 1.0 2.50 2.2 2.71 3.95 11 paper 5.0 5.0 1.50 2.6 3.06 3.42 27 rubber ------------------------0.24 textile 3.0 1.5 2.50 4.3 3.59 0.89 3 miscell. -----------------------------2.54 ----- un miscell. (garden waste) 5.0 2.9 3.0 1 3.06 3.89 3 inert 7.7 ---4.77 10 4.04 -----16 leather ---0.2 2.50 ----1.50 ----- al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 144 water surf use 5% residential 28% industrial site 1% industrial 4% commercial / institutional 10% industrial storage 5% future expansion 14% services sector 6% g reen zone 11% public services 15% re s i de n ti al c omme rci al / i n sti tuti on al in du stri al in du stri al si te in du stri al s torage pu bl i c se rvi ce s gre e n z on e fu tu re e xpan si on w ate r su rfu se se rvi ce s se ctor figure (1 ): land use percentage in nassiriya city figure (2): master plan of nassiriya city al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 145 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 ja nu ar y fe b ru ar y m ar ch a p ri l m ay ju n e ju ly months s o li d w a s te g e n e ra ti o n r a te ( k g /c a p it a /d a y ) 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 t e m p e ra tu re ( c ) high level middel level low level temperature figure (3): solid waste generation rate 0 50 100 150 200 250 300 350 400 ja nu ar y fe b ru ar y m ar ch a pr il m ay ju n e ju ly months d e n s it y ( k g /m ^ 3 ) 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 t e p e ra tu re ( o c ) high level middel level low level temperature figure (4): solid waste density al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 146 janau ry fe berau ry m ar a pril m ay june july h ig h i n c o m e m id i n co m e l o w i n c o m e 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 high income mid income low income figure (5): generation rate for each income level janaury feberaury m ar a pril m ay june july h ig h i n c o m e m id i n co m e l o w i n c o m e 200 220 240 260 280 300 320 340 360 380 400 high income mid income low income figure (6): density values for each income level al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 147 metal 4.81% o rgani cs pl asti cs me tal gl ass pape r ru bbe r te xt. mi sc. c om b. mi sc. in comb. metal 5.30% o rgan i cs pl asti cs me tal gl ass pape r rubbe r te xt. mi sc. c omb. mi sc. incom b. metal 4.96% o rgan i cs pl asti cs me tal glass pape r ru bbe r te xt. mi sc. c om b. mi sc. in com b. figure (7 ): solid waste component in high income in wet season figure (8): solid waste component in high income in dry season figure (9): solid waste component in mid income in wet season al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 148 metal 4.76% o rgan i cs pl as ti cs me tal gl as s pape r ru bbe r te xt. mi sc. c omb. mi sc. in comb. misc. incomb . 4.54% o rg an ic s 68 .9 6% glass 5.21% metal 4.77% plastics 4.36% paper 4.57% text. 3.25% rubber 1. 85% o rgan i cs pl asti cs me tal gl ass pape r ru bbe r te xt. mi sc. c omb. mi sc. in comb. metal 4.60% o rgani cs pl asti cs me tal gl ass pape r ru bbe r te xt. mi sc. c om b. mi sc. in com b. figure (10): solid waste component in mid income in dry season figure (11): solid waste component in low income in wet season figure (12): solid waste component in low income in dry season al-qadisiya journal for engineering sciences, vol. 6……no. 1 ….2014 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 1 simulation solar electrical generation power plant by using parabolic trough in basra city amani j. majeed*, dr. saleh e. najim, dr. salman h. hammadi mechanical engineering department university of basra *a_j_majeed@yahoo.com received 29 april 2013 accepted 19 january 2014 abstract a simulation for a solar thermal electric generating system with parabolic trough collectors in basra city is presented. this system consists of three parts: solar collector fields to heating the working fluid, a storage system to store the thermal energy, and power conversion system to convert the thermal energy to electrical. the simulation is presented for all parts. the energy conversion of solar radiation into thermal power along the absorber tube of the parabolic collector is studied. the coupling between the collector and the thermodynamic cycle is made up by heat exchangers, yielding the characteristic temperatures of the cycle. the conventional rankine cycle is used as the thermodynamic cycle, whereby the electric power is calculated. all calculations are performed according to basra climate’s conditions for 21 st of each month in 2007.engineering equation solver (ees) software is used in this simulation. good agreements are obtained when comparing the results of the collector outlet temperatures and gross power of the current model with experimental data belonging to the solar electric generating systems (segs) installed in the mojave desert in southern california, whose solar field is composed by parabolic trough collectors. the analytical model developed combines precision and flexibility, making it an attractive tool for simulation and design of solar power stations in basra city. keywords: parabolic trough solar collector, power plant system, basra city. محاكاةُ محطة توليد الطاقة الكهربائية باستخدام المجمعات الشمسية ذات القطع المكافئ الوعائي في مدينِة البصرة د. صالح إسماعيل نجم أماني جليل مجيد د. سلمان هاشم حمادي قسم الهندسة الميكانيكية-كلية الهندسة جامعة البصرة الخالصة الوعائي المكافئمحاكاة لمنظومة توليد طاقة كهربائيِة حراريِة شمسيِة تستخدم المجمعات الشمسية ذات القطّع لبحثا اقّدُم هذي (parabolic trough َفي مدينِة البصرة. تَْشمُل هذه المنظومِة ثالثة أجزاِء: المجمِع الشمسي المستخدم لتَْسخين المائع الناقل للحرارة ) اقةَ الحراريةَ ومنظومة تحويل الطاقة الحرارية إلى طاقة كهربائيِة، تم َعمل المحاكاة لهذه األجزاء الثالثة. وقد و منظومة لخزِن الط mailto:*a_j_majeed@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 2 الوعائي. المكافئالماَص للمجمِع الشمسي ذي القطع األنبوبتمت دراسة تحويَل طاقةَ اإلشعاِع الشمسِي إلى الطاقة الحراريِة على طول ( تم بواسطة المباّدالت الحراريِة، thermodynamic cycleالشمسي والدورة الثرموديناميكية للمحطة ) إّن الربط بين المجمعِ للحصول على درجاَت الحرارة المناسبة لعمل الدورِة. وقد فَرض أن منظومة تحويل الطاقة مكونة من محطة بخارية كهربائية تعمل (، حيث تم حساب الطاقة الكهربائية لهذه المحطة. لعمل conventional rankine cycleبدورة رانكن التقليدية ) وافترض انه يوم صحو وخالي من الغيوم. كما تم تصميم وتحليل هذه 1002( من كل شهر لعام 12المحاكاة لهذه المحطة أُختيَر يوم ) أوضحت . engineering equation solver (ees) جياتبرم استعملت المحاكاةالمحطة وفقا لظروف مناخ مدينة البصرة. لعمل وجودة في صحراِء المقارنة بين نَتائَِج النموذِج الحالي مع النَتائَِج التجريبيِة التي تَُعوُد إلى أنظمِة توليد الطاقة الكهربائيِة الشمسيِة الم ات القطّع المكافىِء الوعائي، توافقا كبيرا. أن الدقِّة موييف في جنوب كاليفورنيا، التي يتكون حقلها الشمسي ِمن مجمعات شمسية ذ الطاقة والمرونِة للنتائج ِ التحليليِة النموذجيِة المتطورِة التي تم الحصول عليها، تجعلها أداة جّذابة للمحاكاِة وتشجع على تصميِم محطاتِ .الكهربائية الشمسيِة في مدينِة البصرة nomenclatures description symbol apparent direct normal solar flux at the outer edge of the earth's atmosphere [w/m 2 ] a the cross-sectional area of the inside tube of the absorber[m 2 ] 1,abs a the cross-sectional area of the absorber[m 2 ] abs a the cross-sectional area of the glass envelope [m 2 ] env a apparent atmospheric extinction coefficient b specific heat at constant pressure[j/kg k] p c total number of collectors in the field co llecto r n the mean ambient temperature ambt overall heat loss coefficient between the tank and the environment [kj/hr °c] ua volumetric flow rate of the heat transfer fluid [m 3 /s] htfv . mass flow rate [kg/s] . m the density [kg/m 3 ] ρ introduction sustainable energy is energy that, in its production or consumption, has minimal negative impacts on human health and the healthy functioning of vital ecological systems, including the global environment. it is an accepted fact that solar energy is a sustainable form of energy, which has attracted more attention during recent years, as in broesamle [1] 2001. lippke 1995 [2] produced a detailed thermodynamic simulation model of the solar electric generating system (segs) solar field and power cycle using easy simulation software (lippke, 1995). the objective of this model was to simulate system behavior during part-load conditions (such as winter months and cloud covered days). kribus et al. 1997 [3] demonstrated that the main results of a feasibility study of a combined cycle electricity generated plant, are driven by highly concentrated solar energy and high-temperature central receiver technology. al-sakaf 1998 [4] produced many international studies and experiences have been shown that the solar thermal power plants are the most economic form of the solar electricity al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 3 generation. almanza and lentz 1998 [5] demonstrated that it is possible to generate electricity by direct steam generation in parabolic troughs. saturated steam at 165 o c and 6.89 bars can be supplied to a 2.24 kw steam stuart swan motor of the two piston engine type in order to produce mechanical energy, as well as electric energy through a generator, using the recirculation process concept to produce steam. beerbaum and weinrebe 2000 [6] analyzed the potential and the cost-electiveness of centralized and decentralized solar thermal electric (ste) generation in india. comparing the levelized electricity costs (lec) for ste with the corresponding lec for the electricity generating options used at present, they find that ste is an economically viable technology under favorable conditions, i.e. in areas with high insolation levels and provided that capital is available at low interest rates. a solar electric generating system (segs), shown in figure (1), refers to a class of solar energy systems that use parabolic troughs in order to produce electricity from sunlight. the parabolic troughs are long parallel rows of curved glass mirrors focusing the sun’s energy on an absorber pipe located along its focal line. these collectors track the sun by rotating around a north-south axis. the heat transfer fluid (htf), an oil, is circulated through the pipes. under normal operation the heated htf leaves the collectors with a specified collector outlet temperature and is pumped to a central power plant area. there, the htf is passed through several heat exchangers where its energy is transferred to the power plant’s working fluid, which is water or steam. the heated steam is used in turn to drive a turbine generator to produce electricity. the facility discussed in this paper is the 30 mwe segs plant in basra city. the plant model in the following the plant is divided into three subsystems: the solar collector field, the storage tank model, and the power plant model. all these models are shown schematically in figure 1. figure(1): solar power plant system al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 4 the solar collector field the thermal performance model of the segs parabolic trough plant is based upon a steady-state efficiency model for the collector using empirical coefficients [7,11]. figure 2: the heat collection element a detailed physical model for the collector is presented in this work. to derive the appropriate differential equations, the heat collection element (hce) in figure (2) is considered. the hce consists of the absorber pipe in which the htf flows. a glass envelope covers the absorber pipe, which is assumed to have no radial temperature gradients. partial vacuum exists in the annulus between the absorber pipe and the glass envelope. a transient energy balance for the htf leads to the following partial differential equation for the htf temperature: gained htf collector htf htfphtf htf abshtfphtf q z t n tv c t t ac       )( . ,1,,  (1) the distance along the collector is z, and t is the time. the boundary condition for equation (1) is: )(),0( , tttt inlethtfhtf  (2) with inlethtf, t as the htf collector field inlet temperature. the initial condition for equation (1) is: 0, )0,( htfhtf tzt  (3) the differential equation for the absorber temperature is given through [12]: gainedinabsorbedabs abs absabspabs qqq t t ac    .,,  (4) the initial condition for equation (4.4) is: 0, )0,( absabs tzt  (5) glass envelope absorber tube heat transfer fluid partial vacuum between envelope and absorber al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 5 the glass envelope is assumed to have no radial temperature gradients. the differential equation for the envelope temperature is given through [12, 13]: ..,, exinabsorbedenv env envenvpenv qqq t t ac     (6) the initial condition for equation (4.6) is: 0, )0,( envenv tzt  (7) the interacting dynamic of the temperatures given through the differential equations (1), (4) and (6) is determined by the heat transfer between the htf, the absorber, and the envelope. the solar collector field model predicts the solar collector field outlet temperature well, especially for days with good weather conditions. climate condition taken from the meteorological air of the city of basra [14]. storage tank model for the simulation, the trough is assumed to provide heat to a thermal storage system. the advantage of having a thermal storage system is that it can store the thermal energy generated during the peak radiation hours for later use when solar radiation is unavailable. the simulation assumes that the tank may operate with significant degrees of stratification. the model approaches the thermal stratification of the tank by assuming that the tank consists of n fully-mixed volume segments, as shown in figure 3. higher values of n result in more stratification. for the special case of n=1 the tank is modeled as a fully mixed tank and no stratification effects are possible [15]. the governing differential equation for the ith node as follows [16, 17]: figure(3): n-node tank al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 6 )t(tmf)t(tmf )t(tmf)t(tmf)t(t c ua dt dt m is,1is, 1im, 2 iis,1is, 1im, 1 i is,l l l iis,c c c iis,amb ip is, i               .. ... (8) where the control functions are: fi c = 1, if fluid from heat source enters node i, 0 otherwise fi l = 1, if fluid returning from load enters node i, 0 otherwise fi 1 = 1, if the netflow 1im,m  . enters node i from the node above = -1, if the netflow 1im,m  . goes from node i to the node above = 0, if there is no flowstream between node i and the node above fi 2 = 1, if the netflow 1im,m  . enters node i from the node below = -1, if 1im,m  . goes from node i to the node below = 0, if 1im,m  . = 0 the power plant in analyses of power cycle it is assumed that all flows of mass and energy are steady, so that the steady state conservation equations are applicable [18,19,20]. it is also assumed that all components are adiabatic and we neglect the usually small kinetic and potential energy differences between the inlet and outlet. the rankine cycle is simplified as shown in figure 1 for easier modeling. the heat exchangers are considered to be a single heat exchanger instead of being divided into preheater, steam generator and superheater. it is now assumed that pure water is entering the single heat exchanger and superheated steam is leaving. results and discussion the calculations were performed under basra climate conditions for sunny days in 2007. engineering equation solver software (ees version 6.287) was used to conduct the system calculations. figures (4-7) show the direct normal (idn) and direct (idn cos𝞱) solar radiation as a function of time. it is noted that idn increase from sunrise to reach a maximum value at mid-day after falling to reach zero at the sunset time. the component (idn cos𝞱) profile depended on the incident angle. since the collector follow the sun path from east to west, the direct solar radiation (idn cos𝞱) increases at morning hours after a slightly decrease at mid-day due to non-zero incident angle. the useful solar radiation represents by (idn cos𝞱) is about 600 w/m 2 at the winter and 900 w/m 2 at the summer. which represent a maximum value due to a small incident angle (about 6 o ). figure (8) show the outlet fluid temperature of the collector during the four seasons. as it expected, the temperature profile related to the solar radiation component (idn cos𝞱) that absorbed by the collector tube. figures (10) and (11) show the gross power in[mw] vs. time for june and december, respectively, for pure solar plant and for solar plant that use storage tank. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 7 in figures (12-15) the heat loss from the absorber tube increases with increasing of its length. this can be explained as for long absorber tube, the hydrodynamic losses of htf flow increase and htf of internal flow decreases which means increase in the heat losses to the surrounding. figures (16) and (17) show the relation between the efficiency of power cycle and month at (12:00 p.m.) for 21 st of each month in 2007 for the case of pure solar power plant cycle and for solar power plant supported by storage tank, respectively. it is noted that this efficiency reach to value about (35 %) during months from march to september in the case of pure solar power plant cycle. in case of solar power plant supported by storage tank, the efficiency has a similar value during the months from february to september. good agreements are obtained when comparing the results of the collector outlet temperatures and gross power for current model with experimental data belonging to the solar electric generating systems (segs) installed in the mojave desert in southern california [21], figures(18) and (19) show the comparison of collector outlet temperatures and gross power on june respectively. conclusions the most important conclusions that can be obtained from the present study are the followings: 1the solar field model shows that higher solar field outlet temperatures were achieved in the summer and spring for specified chosen days in 2007. the system model also shows that higher gross electric power production was achieved in summer and spring for specified chosen days in 2007. 2the performance difference is more noticeable in the summer months than in the winter months. 3the simulation is a reliable tool to predict the system performance under various environmental conditions. 4the results of this study give guidance for the possible use of parabolic trough application for the bio sun project in basra city. references [1] broesamle, h., mannstein, h., schillings, c., and trieb., f., “assessment of solar electricity potential in north africa based on satellite data and a geographic information system solar energy”, solar energy, vol. 70, pp.1–12, (2001). [2] lippke, f., “simulation of the part-load behavior of a 30 mwe segs plant”, prepared for sandia national laboratories, albuquerque, nm, sand95-1293. june, (1995). [3] kribus, a., zaibel, r., carey, d., segal, a., and karni, j., “a solar-driven combined cycle power plant”, solar energy vol. 62, no .2, pp. 121-129, (1998). [4] al-sakaf, h. omar, “application possibilities of solar thermal power plants in arab countries”, renewable energy, vol. 14, nos. 1-4, pp. 1-9, (1998). [5] almanza, r. and lentz, a., “electricity production at low powers by direct steam generation with parabolic troughs”, solar energy, vol. 64, no. 1-3, pp. 115-120, (1998). [6] beerbaum, s. and weinrebe, g., “solar thermal power generation in india a techno-economic analysis” renewable energy, vol. 21, pp. 153-174, (2000). al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 8 [7] klaib, h., nitsch, j., and sprengel, u., “solar thermal power plants for solar countries technology, economics and market potential”, applied energy, vol. 52, pp. 165-183, (1995). [8] odeh, d. s., morrison, l. g., and behnia, m., “modeling of parabolic trough direct steam generation solar collectors”, solar energy, vol. 62, no. 6, pp. 395-406, (1998). [9] european commission “concentrating solar power from research to implementation”, 2007. http:// www.ausra.com. [10] goswami et. al. “energy conversion” mechanical engineering handbook .ed. frank kreith .boca raton: crc press llc, (1999). [11] camacho, e. f., berenguel, m. and rubio, f. r., “advanced control of solar plants”, springerverlag, berlin heidelberg new york, april 15, (1997). [12] stuetzle, a. t., blair, n., mitchell, w. j., and beckman. a. w., “automatic control of a 30 mwe segs vi trough plant”, solar energy, vol. 76, pp. 187-193, (2004). [13] el-fadar, a., mimet, a., azzabakh, a., garcía, m., and castaing, j., “study of a new solar adsorption refrigerator powered by a parabolic trough collector”, applied thermal engineering, vol. 29, issues 5-6, pp. 1267-1270, april(2009). [14] www.wunderground.com/history/airport. [15] li, z. f., sumathy, k., “simulation of a solar absorption air conditioning system”, energy convers manage, vol. 42, pp. 313–27, (2001). [16] duffie, j. a., and beckman, w. a., “solar engineering of thermal processes”, new york, john wiley and sons, inc., (1991). [17] mazloumi, m., naghashzadegan, m., and javaherdeh, k. “simulation of solar lithium bromide– water absorption cooling system with parabolic trough collector” energy conversion and management, vol. 49, pp. 2820–2832, (2008). [18] el-wakil, m. m., “power plant technology”, mcgraw-hill book company, (1984). [19] status report on solar thermal power plants, pilkington solar international: 1996. report isbn 3-9804901-0-6. [20] el-sayed, h. a. m., “substitution potential of solar thermal power stations in electrical energy systems”, renewable energy, vol. 6, no. 7, pp. 849854, (1995). [21] rolim, m. m., fraidenraich, n., and tiba, c., “analytic modeling of a solar power plant with parabolic linear collectors”, solar energy, vol. 83, pp. 126–133, (2009). [22] personal communication with an “anajibiyah power station”. http://www.ausra.com/ http://www.wunderground.com/history/airport al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 9 al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 10 figure (10): calculated gross power output (with and without storage tank) vs. time on 21 june 2007. gross power without storage gross power with storage figure (11): calculated gross power output (with and without storage tank) vs. time on 21 december 2007. gross power without storage gross power with storage al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 11 fig. 16: the efficiency of the power cycle vs. months without storage tank. fig. 17: the efficiency of the power cycle vs. months by using storage tank. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 119 effect of transverse reinforcement on the axial compressive strength of reinforced concrete columns haitham al-thairy civil engineering department, college of engineering, university of al-qadissiya, iraq. email: haitham.althairy@qu.edu.iq received 13 august 2015 accepted 29 december 2015 abstract this paper presents an experimental study on the effect of transverse reinforcement on the axial compressive strength of rectangular and circular cross sectional shape reinforced concrete (rc) columns under axial compression. twenty specimens of small scale rc columns specimens were considered in the experimental tests. ten of the columns specimens have a square cross sectional shape with dimensions of (150×150) mm and the other ten specimens have a circular cross sectional shape with a diameter of 150mm. for each cross sectional shape, the columns are classified into two groups of five columns: the first group contains short columns according to aci-code requirements (aci318, 2011) and the other group consists of long columns. each group uses same longitudinal reinforcement ratio but with five different transverse reinforcement ratios represented as a volumetric ratio of the transverse reinforcement. an experimental test has been conducted to determine the maximum axial compressive load at which each concrete column would fail. the experimental test results have shown that increasing of the volumetric ratio of the transverse reinforcement leads to a considerable increase of the axial load resistance of the column for both rectangular and circular columns and for both cases of long and short columns. the study has also showed that using equations suggested by the aci-code to determine the axial compressive strength of rc columns with tie reinforcement that are spaced at distances exceed that suggested by the code, gives overestimated predictions of the column axial resistance which may results unsafe design. keywords: rc columns, axial strength, transverse reinforcement, experimental tests, volumetric ratio. انضغاط الحمال معرضةالكونكريتية ال لالعمدةالتسليح العرضي على مقاومة االنضغاط تاثير محورية الثائري هيثم علي بادي في قسم الهندسة المدنية/كلية الهندسة / جامعة القادسية يتدريس mailto:haitham.althairy@qadissuni.edu.iq al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 120 الخالصة عمدةاالتلك و مقاومة المسلحة يقدم المشروع دراسة عملية )مختبرية( للعالقة بين نسبة التسليح العرضي في األعمدة الخرسانية عشرة من نماذج .ة المسلحة يعمدة الخرسانوذج من االمين نتم إجراء الفحوصات المختبرية على عشر . لمحوريةاغاط ضاالنلقوة بقطر يبلغ الشكل ريةئرى بمقاطع عرضية داخو العشرة االملمتر 051× 051تمتلك مقاطع عرضية مربعة الشكل بابعاد االعمدة مجموعتين : المجموعة األولى وعددها خمس أعمدة صنفت الى واحد طع عرضي ذات مقاعمدة كل عشرة تم تقسيم . ملمتر 051 المجموعة الثانية وعددها خمس أعمدة أيضا تم و aci 318-11 حسب متطلبات مدونة معهد الخرسانة االمريكي كأعمدة قصيرة لتسليح الحجمية لنسبة الوتغيير العمدة الخمسة من الكل مجموعة تصنيفها كأعمدة طويلة حيث تم تثبيت نسبة التسليح الطولي فحص تم . العرضي الى حجم لباب الكونكريت المحاط باالطواقللتسليح الكلي الحجم موع جالتي تمثل نسبة م العرضي )األطواق( لكل نسبة تسليح عرضي لمعرفة تأثير تغير التسليح العرضي على قابلية تحمل و لكل عمود الستاتيكية المحورية االنضغاط مقاومة مقاومة االعمدة الخرسانية ) ملحوضة في بينت الدراسة ان زيادة النسبة الحجمية للتسليح العرضي تؤدي الى زيادة .المحورية من قبل مدونة معهد الخرسانة قترحةالم التالمعاداستخدام المحورية. كما بينت الدراسة ان االنضغاط النحيفة و القصيرة ( لقوة في الحالت التي تكون فيها لالعمدة الكونكريتية المحملة محوريا المحرية لحساب مقاومة االنضغاط aci 318-11 األمريكي األمر الذي عالية تحملتعطي قيم المسافات بين حديد التسليح العرضي ) االطواق( اكبر من الحدود العظمى المحددة من قبل الكود .لالعمدة الكونكرينية ينتج عنة تصميم غير امنقد ., نسبة حجميةاعمدة خرسانية مسلحة , مقاومة محورية , تسليح عرضي, فحوصات مختبرية :كلمات الداللة . 1. introduction reinforced concrete (rc) columns are main structural members of any reinforced concrete building and their failure may be cause failure of the whole structure of that building. besides the uniaxial or biaxial bending moments that a rc column may be subjected to, columns are mainly designed to resists axial compressive loads imposed from the upper stories of the buildings. for this type of column resistance (i.e. the axial compressive load resistance) sec. 10.3.6.1 of the american concrete institute design code for reinforced concrete buildings (aci318, 2011) has suggested the following equations to predict the design axial compressive strength: 1. for columns with spiral reinforcement )afy +)a -(acf 0.85ø(0.85=øp ststgnmax  (1) 2. for columns with tied reinforcement )afy +)a -(acf 0.80ø(0.85=øp ststgnmax  (2) where ag is the gross cross sectional area of the rc column; ast is the total area of the longitudinal reinforcement steel bars; fy is the yield stress of the longitudinal reinforced steel; ́ is the compressive strength of the concrete; ø is the strength reduction factor which is taken as 0.7 for spiral reinforcement and 0.65 for tie reinforcement. equations 1 or 2 may be expressed in a general form as follows: )p0.8)ø(por (0.85=øp long. conc.nmax  (3) al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 121 where pconc. is the axial compressive strength of the rc column comes from the concrete; plong. is the axial compressive strength of the rc column comes from of the longitudinal reinforcement. it can be noticed from eq 3 that the aci-code only considers the contribution of the concrete and longitudinal steel reinforcement in the axial compressive strength of the rc columns neglecting the contribution of transverse reinforcement (ties or spirals) which may considerably affect the total axial compressive strength of the rc columns. however, sec. 7.10.5 of aci-code (aci318, 2011) suggests limits for the maximum spacing (smax) of the transvers reinforcement to be used in the design of rc columns, which are the minimum of: 16 times the diameter of the longitudinal reinforcement steel bars (db); 48 times the diameter of transverse reinforcement steel bars (dtie) or; the minimum dimension of the column cross section. nevertheless, as will be shown in this study, these limits gives very close spacing of the transverse reinforcement and neglects the cases of higher spacing distances which may also be applicable in many design situations. on the other hand, many research studies have been carried out to investigate the effect of transverse reinforcement on the behaviour and failure of short rc columns. however, long rc columns have rarely been considered in these previous researches. for instance, chung et al. (2002) have suggested an equation to determine the magnitude of the increase in strength of confined concrete. the suggested equation was based on experimental data and nonlinear multiple regression method of sixty-five reinforced short concrete columns. sharma et al. (2005) have presented an experimental study to investigate the strength of short columns with high strength concrete confined by spirals and ties reinforcement under increasing concentric compression load. the volumetric ratio, spacing, configuration and yield strength of transverse reinforcement are all considered as test variables along with the ratio of longitudinal reinforcement. hong et al. (2006) and junior and giongo (2004) have also conducted an experimental study to determine the effect of low volumetric ratio of lateral tie reinforcement on the high strength concrete and steel fibre high strength concrete column respectively. it has been shown in hong et al. study (hong et al., 2006) that columns specimen’s with higher volumetric ratios in conjunction with lower-grade tie yield strength shows better performance than those with lower volumetric ratios in conjunction wiyh higher-grade yield strength. on the other hand, junior and giongo study (junior and giongo, 2004) have revealed that steel fibre may be help to avoid the premature concrete cover spalling. wang and wue (2010) carried out an experimental investigation on the effect of the confinement using aramid fibre-reinforced polymer sheets on the strength of square high-strength concrete short columns. regression formulae were developed for strength and strain based on the experimental results. two types of axial stress-strain curves were observed from the tests results depending on the form of afrp wrapping. it has also been shown that the strength and ductility of the columns increases when fully wrapped afrp sheets are used whereas only the strength increases when partially wrapped afrp sheets are to be used khaleek et al. (2012) has conducted an experimental study on small scale rectangular and circular cross section short columns to determine the effect of volumetric ratio of the transverse reinforcement on the axial compressive strength. it has been shown that the column axial compressive resistance significantly increases when the volumetric ratio of transverse reinforcement has been increased. however, since the study has only considered short columns, as defined by aci-code classification of columns, their results could not be generalized to include other cases of long columns because of the difference in behavior and failure modes between two types of columns. shin et al. (2012) have also conducted experimental tests on eight small scale rectangular cross section short columns subjected to axial compressive load to cause column failure. it has been al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 122 concluded that increasing of the volumetric ratio of transverse reinforcement results to a considerable increase of the column ductility which is indicated by the number of cyclic loading that the column can sustain before experiencing failure. it has also been found that the increasing in ductility of the column was due to increasing of the compressive strength of the column owing to increasing of the confinement resulted from the transverse reinforcement (ties). öztekin (2012) suggested a method to predict the confined compressive strength of square concrete columns using artificial neural networks (ann). the ann model has been developed by using experimental test results of normal and high strength square concrete columns. several parameters have been addressed in the developed model including numbers and diameters of longitudinal and transverse reinforcements, spacing and configuration of the transverse reinforcement. the validation results have shown that the developed ann model predicted more accurate results compared to the available analytical models. radnić et al. (2013) have recently presented an experimental study to investigate the effect of concrete confinement on the compressive strength and ductility of concrete beam subjected to pure bending. the effect of the form and spacing of stirrups on the capacity and ductility of rc beams were investigated in the study. it has been shown that the ultimate strength capacity and deflection of rc beam increase with decreasing of stirrups spacing. moreover, it has been concluded that the stirrup form has a considerable effect on the ultimate load carrying capacity and ductility of rc beam. it is clear that all the previous research studies have only considered the short reinforced concrete columns in their investigations. therefore, the main objective of the present research is to investigate the effect of transverse tie reinforcement on the axial compressive strength of the rc short and long columns. series of experimental test will be conducted on twenty small scale rectangular and circular cross section long and short columns specimens. all rc columns specimens will be subjected to an incremental increasing static axial load up to column failure. the experimental test results will be compared with the corresponding aci-code design equations. 2. experimental program and test setup this section describes in details the experimental program including test setup and column specimens used in experimental tests of this study and present the experimental test results. 2.1. concrete mixture ingredients all material used in the concrete mixture used to cast the concrete column specimens (fine aggregate, coarse aggregate) are tested in the constructional material laboratory at civil engineering department/college of engineering/the university of al-qadissiya as follows: 2.1.1. cement: the ordinary portland cement type (i) available in local markets in iraq and conform to the iraqi specification no. 5/1984 was used in the present study. 2.1.2. fine aggregate (sand): natural sand with maximum size of 10 mm was used in this study. experimental tests have been carried out to determine the grain size distribution; sulfate and fine material contents and the results are shown in table 1. test results have shown that the grain size distribution conform to the iraqi specification no.45/1984. on the other hand, sulfate and the fine materials contents are comply to the requirements of the iraqi specification no.45/1984. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 123 2.1.3. table 2. test results have shown that the grain size distribution conform to the iraqi specification no.45/1984. on the other hand, sulfate and the fine materials contents are comply to the requirements of the iraqi specification no.45/1984. 2.1.4. reinforcement steel bars: the mild steel bars have been used to reinforce the concrete columns with diameters of 10mm and 8mm for longitudinal reinforcement and 6 mm for transverse reinforcement. a uniaxial tensile test has been conducted to determine the yield stress of the reinforcement steel (fy) to be used thereafter in the aci equations (i.e. eq. 1 and eq. 2). error! reference source not found. shows the uniaxial tensile test results of the reinforcement steel bars. 2.1.5. water: tap water was used in this study for mixing and curing test specimens. 2.2. rc columns specimens. all the ingredients of the concrete mixture were mixed with each other using a mix ratio of 1:1.75:3.5 (cement: sand: aggregate). a tap water was added using water to cement ratio (w/c) equal to 0.48 to form a fresh concrete mixture. the concrete mixture with the aforementioned properties has been used to cast twenty reinforced concrete columns with dimensions, longitudinal and transverse reinforcements as shown in table 4 and figure 1. ten of rc column specimens have a square cross section with dimensions of (150×150) mm and the other ten columns have a circular cross section with a diameter of 150mm. for each cross sectional shape, the columns are divided into two groups of five columns: the first group contains short columns defined according to sec. 10.10.1 of aiccode (aic318, 2011) and have a total length of 800mm for rectangular section column which are designated as (rs0rs4) and 750 mm for circular section columns which are designated as (cs0cs4). the other group contains long column (aic318, 2011) with a length of 1200mm for square cross section columns which are designated as (rl0rl4) and of 1300mm for circular cross section column which are designated as (cl0cl4). each group of five rc columns uses same longitudinal reinforcement ratio but with five different transverse tie reinforcement ratios represented as a ratio of the tie reinforcement volume to the concrete core volume. the transverse tie reinforcement ratio has been changed by changing number of ties in each column as shown in table 4. ply-wood and pvc pipes were used as forms to cast the rectangular and circular columns respectively. due to the limitation in resources available in the laboratory, each ten columns with same cross sectional shapes were cast in two different batches. for each cast batch, twelve concrete cubes with dimensions of (150×150×150) mm have also been case to determine the compressive strength of concrete corresponding to each ten columns. after casting, all rc column specimens and concrete cubes have been remolded, marked and cured for time duration of 28 days by immersing in a warm water basin (at 20 c o to gain the maximum concrete strength and to be ready for the test. 2.3. testing and loading of rc column specimens. 2.3.1. concrete cubes: after curing, axial compressive tests have been carried out on the twelve concrete cubes to obtain the compressive strength of concrete corresponding to each ten coarse aggregate (gravel): natural coarse aggregate with maximum size of 20 mm was used in this study. experimental tests have been carried out to determine the grain size distribution; sulfate and fine material contents and the results are shown in al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 124 column. the compression test machine available at constructional material laboratory at civil engineering department/ college of engineering/ the university of al-qadissiya was used to perform the tests; table 5 shows the compressive strength of the concrete cubes corresponding to each concrete batch with the average values used for each group of ten columns. 2.3.2. concrete columns: after a 28 day of curing, a static axial compressive load bearing tests were conducted for the reinforced concrete columns specimen to capture the axial compressive strengths to each column. the universal test machine available at constructional material laboratory at civil engineering department/ college of engineering/ the university of al-qadissiya was used to perform the tests, see figure 2. the ends supports of all tested columns simulate the simply support conditions with no sideways movement (braced columns) because the top and bottom ends of the columns are not capable to move laterally. to ensure a uniform distribution of the axial compressive load, a square steel bearing plate with dimensions of (200×200×5) mm (width ×length× thickness) was fixed at the top end of each column during the test. an incremental increasing axial static load has been applied to each rc column until the column experienced failure represented by a reloading of loading gages of the test machine. the axial load at which failure occurs was recorded for each tested column and the results will be presented and discussed in the next section. 3. discussion of the test results 3.1. failure modes figure 3 and figure 4 show the rc column specimens shapes after failure. as can be seen from these figures, all tested columns have experienced similar failure pattern represented by concrete crushing at the top of the column followed by generating of cracks and splitting of the concrete cover surrounding the transverse reinforcements at the top quarter of the rc column. it can also be noticed from figure 3 and figure 4 that the longitudinal reinforcement bars have also experienced global buckling particularly near to the loaded end of the column. this can be attributed to the effect of the axial load and because the longitudinal reinforcement bars have no lateral support when the concrete surrounding the longitudinal reinforcement bars have been crushed at the beginning of loading. one of the functions of transverse reinforcements in columns is preventing the main longitudinal bars from buckling outward, spalling the concrete and causing early collapse. without ties being properly spaced, the main steel could not be relied upon to reach its yield stress. 3.2 axial compressive strength. as mentioned before, each column specimen has been subjected to an increment axial static load until the column experienced failure using a load increment of 5kn. failure of each column was detected by a reloading of the loading gage of the test machine which occurs when the rc column crushes or buckles. table 6 and table 7 and figure 6 to figure 8 show the relationship between failure load and the volumetric ratio of transverse reinforcement for all tested columns. it can be seen form table 6, figure 5 and figure 6 which demonstrate the relationship between the axial compressive strength of short columns and volumetric ratio of the transverse reinforcement that increasing of the volumetric ratio of the transverse reinforcement resulted increasing of the axial compressive load at which the columns have failed. increasing of the volumetric ratio of the transverse reinforcement from 1.4961×10 -3 to 3.9896×10 -3 for rectangular sections and from 3.16×10 -3 to 9.49×10 -3 for circular sections has increased the column axial compressive resistance from 316.5kn to 410. 8kn and from 292.4kn to 394.7kn for rectangular and circular sections respectively with increasing rate of 30% and 35% for rectangular and circular sections respectively. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 125 similarly, table 7, figure 7 and figure 8 show that increasing of the volumetric ratio of the transverse reinforcement from 3.23.0×10 -3 to 6.3156×10 -3 for rectangular sections long column and from 5.48×10 -3 to 16.45×10 -3 for circular sections long columns has increased the column axial compressive resistance from 385kn to 523kn and from 270kn to 455.6kn for rectangular and circular sections respectively with increasing rate of 36% and 68.7% for rectangular and circular section respectively. this is an expected behavior since increasing of the volumetric ratio of the transverse reinforcement causes increasing of the confinement of the concrete core surrounded by the transverse reinforcement hence results increasing of the concrete compressive resistance (cusson, d. paultre, p., 1994, öztekin, 2012, radnić at al., 2103) and then increasing of the column axial compressive load strength. moreover, increasing of the transverse reinforcement may also increase the strength of longitudinal steel bars and prevent the steel bars from buckling out and causing early failure, see figure 3 and figure 4. 4. comparison with aci318-2011 code equations in this section, a comparison is presented and discussed between the column axial compressive strength recorded from the experimental test with that calculated using the equations suggested in sec. 10.3.6.1 of acim318-11 code (i.e. eq 1 and eq. 2 in present study). as mentioned before, the sec. 7.10.5 of aci-code has suggested maximum spacing limits between the transverse reinforcement which is equal to 150mm for rc column specimens used in the presents study however, the actual spacing used in the present study exceed this limit as listed in table 6 and table 7. nevertheless, in order to investigate the applicability of the aci equations for spacing values higher that maximum spacing limits suggested by aci -code, the following comparisons were conducted. firstly, the axial compressive strength of rc columns was calculated according to the equations eq. 2. the average of the experimental values of concrete compressive strength corresponding to each cast batch as listed in table 8 were substituted in eq. 2. one the other hand, the experimental value of the yield stress of the reinforcement steel bars obtained from the uniaxial tensile test of steel bars as presented in table 8 has also been used in eq. 2 to calculate the axial compressive strength of rc columns. table 6 and table 7 list the calculated axial compressive strength for each column along with the experimentally recorded values. table 6, table 7, figure 9 and figure 10 compare the experimentally recorded values of the column axial compressive strengths with those calculated by aci – code equation. it can be noticed from table 5 and table 6 along with figure 9 and figure 10 that the aci-code equation gives overestimated values of the axial compressive strength of the rectangular shape rc columns compared with the values recorded experimentally particularly for long rc columns specimens. however, the aci-code equations predict underestimated values of the axial compressive strength of circular shape column especially for high values of the volumetric ratio of transverse reinforcements. the axial compressive strength values calculated by aci-code equations do not account the effects of transverse reinforcement of the rc columns strength. it only accounts for the compressive strength of concrete and strength of the longitudinal reinforcement steel bars. the overestimated perdition of the column’s axial compressive strength of the rc column may result unsafe design of the column. on the other hand, the underestimated prediction of the column’s axial strength may results uneconomic design particularly when high values of the volumetric ratio of transverse reinforcements would be used. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 126 5. summary and conclusions. this study has presented, in detail, the research undertaken by the author to investigate the effect of transverse reinforcement on the axial compressive strength of reinforced concrete columns subjected to axial compressive load. the study is also aimed to assess the accuracy of equations suggested by aci-code to determine the design axial capacity of rc column. the main findings and conclusions that may be extracted from the study are as follows: 1. increasing of the volumetric ratio of the transvers reinforcement of the rc column results increasing of the axial compressive strength of the rc column. this behavior is valid for short and long columns. 2. failure of the rc column under axial compressive load starts by bearing or crushing at the loaded end followed by splitting of the concrete cover. for long column specimens with low transverse reinforcement ratios, the aforementioned failure is accompanying with buckling of the longitudinal reinforcement, particularly near the loaded end of the column caused by increasing of the effective length of the longitudinal reinforcement due to crushing the concrete surrounding it. 3. using the aci-code equations for rc column with transverse or ties reinforcements spaced at distances exceed the maximum limits suggested by the code may give either over estimated or underestimated prediction of the axial compressive strength of the column. this could result unsafe or uneconomical design. 4. the effect of increasing the transverse reinforcement on increasing the axial compressive strength of rc column is more visible in short columns than that in long columns. this can be attributed to the confining due to transverse reinforcement which has more effect in short columns than long columns. references [1] aci committee 318 2011. building code requirements for structural concrete. american concrete institute, farmington hills, usa. [2] chung h.s., yang k.h, lee y.h, and eun h.c, 2002. strength and ductility of laterally confined concrete columns, can. j. civ. eng., 29:820–830. [3] cusso d. and paultre, p.1994. high-strength concrete columns confined by rectangular ties. j. struct. eng., 10.1061/(asce)0733-9445,120:3(783), 783-804. [4] hong k.n., han s.h. and yi, s.t. 2006. high-strength concrete columns confined by low-volumetric-ratio lateral ties, engineering structures, 28:1346–1353. [5] junior h.c.l and giongo, j.s.2004. steel-fibre high-strength concrete prisms confined by rectangular ties under concentric compression, materials and structures, 37:689-697 [6] khaleek a., yadav r. k. and chandak r. 2012. effect of lateral confinement on strength of concrete, isca journal of engineering sciences, 1: 40-44. [7] öztekin e. 2012. prediction of confined compressive strength of square concrete columns by artificial neural networks. international journal of engineering & applied sciences (ijeas), vol.4, issue 3:17-35. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 127 [8] radnić j., markić r., harapin a. and matešan d. 2013. effect of confined concrete on compressive strength of rc beams. advances in concrete construction, vol. 1, no. 3 :215225. [9] sharma u.k., bhargava p. and kauskik s.k. 2005. behaviour of confined high strength concrete column under axial compression. journal of advanced concrete technology. 3: 267281. [10] shin s., kim j. and ahn j. 2010. transverse reinforcement of rc columns considering effective lateral confining reduction factor. journal of asian architecture and building engineering/november/508. [11] wang y. f. and wue h. l. 2010. experimental investigation on square high-strength concrete short columns confined with afrp sheets. journal of composites for construction, 14: 3:346–351. [12] zahn, franz . 1985. design of reinforced concrete bridge columns for strength and ductility. .university of canterbury. department of civil engineering. table 1: experimental test results of the fine aggregate sieve size analysis fine minerals sieve size % a cumulative passing materials finer than75μm, % % (so3) sulphate contents 01mm 011 3 0.149 4..5mm 89 3.26mm 82 0.09mm 99 611micron .3 211 micron 36 051micron 5 http://ir.canterbury.ac.nz/browse?type=author&value=zahn%2c+franz+august http://ir.canterbury.ac.nz/browse?type=author&value=zahn%2c+franz+august al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 128 table 3: mechanical properties of the reinforcement steel bars form uniaxial tensile test. fy (n/mm 2 ) (%) (n/mm 2 ) fu (n/mm 2 ) (%) 647.89 0.00318 204×10 3 742.76 0.134 table 4: dimensions and reinforcement details of the rc column specimens column specimen designation dimensions (m) h×w×l or d×l kl/r longitudinal reinforce. volumetric ratios of transverse reinforce.(ties) ×(10 -3 ) no. of ties used (ø6mm) rs0 1.05×1.05 ×0.8 17.78 4ø10 2.23 2 rs1 1.05×1.05 ×0.8 17.78 4ø10 2.01 3 rs2 1.05×1.05 ×0.8 17.78 4 ø10 2.98 4 rs3 1.05×1.05 ×0.8 17.78 4 ø10 4.66 5 rs4 1.05×1.05 ×0.8 17.78 4 ø10 6.31 6 rl0 1.05×1.05 ×1.2 26.67 6 ø10 0.50 2 rl1 1.05×1.05 ×1.2 26.67 6 ø10 0.88 4 rl2 1.05×1.05 ×1.2 26.67 6 ø10 3.88 6 rl3 1.05×1.05 ×1.2 26.67 6 ø10 2.48 7 rl4 1.05×1.05 ×1.2 26.67 6 ø10 2.89 8 cs0 0.15×0.75 20 4 ø8 5.48 2 cs1 0.15×0.75 20 4 ø8 8.23 3 cs2 0.15×0.75 20 4 ø8 10.97 4 cs3 0.15×0.75 20 4 ø8 13.71 5 table 2: experimental test for the coarse aggregate sieve size analysis fine minerals sieve size % a cumulative passing materials finer than75μm, % % (so3) sulphate contents .5mm 011 1 0.03 62mm 011 2..5mm 011 31mm 011 04mm 94 01mm 40 5mm 0.3 3.26mm 1.4 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 129 cs4 0.15×0.75 20 4 ø8 16.45 6 cl0 0.15×1.3 34.67 4 ø8 3.16 2 cl1 0.15×1.3 34.67 4 ø8 4.75 3 cl2 0.15×1.3 34.67 4 ø8 6.33 4 cl3 0.15×1.3 34.67 4 ø8 7.91 5 cl4 0.15×1.3 34.67 4 ø8 9.49 6 table 6: the experimentally recorded values of the axial compressive strength for short rc columns with the values calculated using aci-code equations column designation volumetric ratio ×10 -3 experimental values of the axial compressive strength, kn spacing between tie reinforcement (mm) calculated values of the axial compressive strength, kn rs0 3.23.0 295 748 465.2 rs1 2.0139 401 371 465.2 rs2 2.9.95 401 245 465.2 rs3 4.6543 496.2 183 465.2 rs4 6.3156 523 145 465.2 cs0 5.48 270 698 301.3 cs1 8.23 310.6 349 301.3 cs2 10.97 327.5 229 301.3 cs3 13.71 358.7 170 301.3 cs4 16.45 455.6 135 301.3 table 7: the experimentally recorded values of the axial compressive strength for long rc columns with the values calculated using aci-code equations column designation volumetric ratio ×10 -3 experimental values of the axial compressive strength, kn spacing between tie reinforcement (mm) calculated values of the axial compressive strength, kn rl0 0.4860 206.5 1198 515.5 rl1 0.8849 246 395 515.5 rl2 3.8833 254.4 295 515.5 rl3 2.4818 282.2 195 515.5 rl4 2.8986 401.9 166 515.5 cl0 3.16 292.4 1248 301.3 cl1 4.75 319.8 621 301.3 cl2 6.33 348.6 412 301.3 cl3 7.91 373.2 307 301.3 cl4 9.49 394.7 245 301.3 table 5: compressive test results of the concrete cubes section cast batch compressive strength( ́ (n/mm 2 ) ́ average (n/mm 2 ) rect. 1 37.1 37.5 40.5 34.7 41.8 40.74 33.9 35.0 34.7 34.6 37.1 32.3 36.64 circ. 2 31 29 31 31 27 32 31 31 30 26 31 32 30.25 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 130 table 8: concrete compressive strengths and steel yield stress used to calculated the compressive strength of column specimens according to aci-code. cast batch section shape fc ’ average (n/mm2) fy (n/mm 2 ) axial strength (kn) short columns long columns 1 rect. 36.64 648 465.156 515.54 2 circ. 30.25 648 301.337 301.337 (a) (b) figure 1: reinforcement details of rectangular sections (a) and circular sections (b) rc columns figure 2: universal test machine used in experimental tests. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 131 figure 3: failure modes of square and circular short columns al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 132 figure 4: failure modes of square and circular long columns. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 133 figure 5: relationship between the axial compressive load and the volumetric ratio of the transverse reinforcement of short columns with rectangular sections. figure 6: relationship between the axial compressive load and the volumetric ratio of the transverse reinforcement of short columns with circular sections. figure 7: relationship between the axial compressive load and the volumetric ratio of the transverse reinforcement of long columns with rectangular sections. 300 350 400 450 500 550 2.33e-03 3.10e-03 3.88e-03 4.65e-03 6.21e-03 volumetric ratio of transverse reinforcement a x ia l c o m p re s s iv e s tr e n g th ( k n ) rect. short column 200 255 310 365 420 475 5.48e-03 8.23e-03 1.10e-02 1.37e-02 1.65e-02 volumertic ratio of transverse reinforcement a x ia l c o m p re s s iv e s tr e n g th ( k n ) circ. short column 300 325 350 375 400 425 1.50e-03 1.99e-03 2.99e-03 3.49e-03 3.99e-03 volumetric ratio of transverse reinforcement a x ia l c o m p re s s iv e s tr e n g th ( k n ) rect. long column al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 134 figure 8: relationship between the axial compressive load and the volumetric ratio of the transverse reinforcement of long columns figure 9: comparison between the recorded and the calculated values of the column axial compressive strength for short columns figure 10: comparison between the recorded and the calculated values of the column axial compressive strength for long columns 200 240 280 320 360 400 3.16e-03 4.75e-03 6.33e-03 7.91e-03 9.49e-03 volumertic ratio of transverse reinforcement a x ia l c o m p re s s iv e s tr e n g th ( k n ) circ. long column 250 310 370 430 490 550 0.0e+00 4.0e-03 8.0e-03 1.2e-02 1.6e-02 volumetric ratio of transverse reinforcement a x ia l c o m p re s s iv e s tr e n g th ( k n ) experimentarect. experimentacircl. aci318-rect. aci318-circl. 250 295 340 385 430 475 520 565 0.e+00 2.e-03 4.e-03 6.e-03 8.e-03 1.e-02 volumetric ratio of transverse reinforcement a x ia l c o m p re s s iv e s tr e n g th ( k n ) experimentarect. experimentalcircl. aci318rect. aci318circl. article al-qadisiyah journal for engineering sciences 12 (2019) 038–048 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7702060626. e-mail address: sararaedmajeed43@gmail.com(sara) https://doi.org/10.30772/qjes.v12i1.590 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. analogical reasoning in architecture sara raed majeeda* and basim hasan al-majidia adepartment of architecture, university of technology, iraq, baghdad. a r t i c l e i n f o article history: received 27 march 2019 received in revised form 19 april 2019 accepted 06 may 2019 keywords: analogyical reasoning analogy form function a b s t r a c t the concept of analogy varies with the number of basic inputs and the difference in the influence of the basic inputs affecting their composition. in its general concept, architecture has two aspects related to the nature of the formation of analogue thinking: the first is its physical entity, which reflects the visual and visual values and the connection to the formal aspect, and the conceptual one related to the intellectual aspect and the nature of its composition , through the mutual influence between the reality of the external entity and the nature of the ideas that man tries to reach, the research attempts to explore the concept of one of the necessities of the doctrines and the architectural movements in the production of architecture represented by analogue thinking the problem of research is based on [the need for a clear and specific knowledge in the definition of the concept of analogue thinking as a design strategy and mechanisms for the production of modulation according to analogue thinking at the level of form, structure and function in the products of global architecture] solving the research problem by selecting a set of global samples. in this research, it is assumed that analogue thinking is an integral part of the analogy as a strategy and that to achieve analogue thinking, the products must be content within the reference, a number of different global samples with different time periods have been designed to be based on the strategy of analogue thinking, the variation in the construction period and the variation in their design characteristics in terms of formal, functional and structural. this diversity and diversity of material production in the process of tracing the purpose of the research in particular. in addition, from which these samples can be applied to apply the concepts derived from the theoretical framework to achieve the hypothesis of research. the research aims at building a comprehensive framework for the analogy strategy and revealing its role in the formation of the architectural products, crystallizing a measurement tool for the analogy achieved as a method of thinking and its impact on the continuity of the architectural products and applying it to the architecture to be the reference of evaluation of architectural projects, whether in competitions or the academic field. that analogue thinking depends on the transition of mind by incorporating more than one idea to form the creative product achieved in reality, indicating the difference in the work of the analogy from the other creative channels where analogue play plays a role in the creation and the bringing of unusual ideas, approach to creative design and that man deals with architecture intellectually before the process of production is configurable. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction humans tries to achieve the goals of conscious thinking by reflecting on everything he has produced throughout his history on earth. we can return each product to the idea. analogy thinking through analogies, metaphors and metaphors is profound in terms of qualitative values rather than quantitative ones. which allows for the establishment of creative relationships between the present and the past. the characteristics used to http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i1.590 sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 39 redefine reality rather than simply decorating the language, but to provide a real transition to architecture, although not directly as a building tool, is a good tool for analysis and investigation in particular. the research problem was "the need for a clear and specific knowledge in the definition of analogyical reasoning as a design strategy and mechanisms for the production of modulation according to analogyical reasoning at the level of form, structure and function in the products of global architecture." the research aim was to build a theoretical framework for the strategy of analogyical reasoning and detection its role in the continuity of the thought of architectural products, and the development of a measuring tool for the analogy achieved as a way of thinking and its impact on the formation of architectural products and applied to the architecture to be a reference in the evaluation of architectural projects, whether in competitions or the academic field, the research took descriptive analytical approach in the construction of a theoretical framework that can be adopted as an analytical system to study and extrapolate analogyical reasoning through four parts. the first part deals with the concept of analogy exposed. the most important theories and opinions behind the production, which reflect the different motives and reasons involved in the composition, the second part aims to complete the analytical system in the exploration of the intellectual thinking of multiple meanings and what term in the midst of the composition of the previous intellectual process of the process of physical reality production, which concluded research in identified based on different architectural propositions in fact the theoretical and practical, including the access to the third part, which is the research design and then the fourth part application results and conclusions and recommendations. 2. conceptual framework of the concept of analogy in order to identify the most important definitions of the concept of analogy and connections, will be in this part to clarify the concept of analogy conceptual framework includes the contents of the arabic and foreign dictionaries and then the definition of conventional analogy to the analogy architecture. 2.1. the linguistic and normative connotation of the analogy the concept of analogy came in several pictures according to the dictionaries and sources that touched on the concept in an analogy way: the name of the verb is analogy to the same: an analogy actor is analogy ]11,p40[ ibn mandur says: "this is like him and like him, as it is narrated and likened. ibn bari said: as for the analogy, it is only in those who agree ... the analogy is analogy to saying, "[2, p. 12], the analogy between features such as two things, which can be based on any comparison and is a form of thinking which implies one thing to be analogy to another in a certain respect, based on the analogy known between things in other sides [cambridge1972, p220] from the above it is noted that the concept of analogy refers to the analogy and equality between the features of two things compared to the properties that are used to explain the principle or idea, also known as: "the process of replacing the voice of another voice under the influence of a third voice close to him in the word or sentence , and can be expanded to include the interaction of two consecutive voices resulting in one voice different from them "[19, p217] it is also known as "adaptive adaptations of sound while adjacent to other sounds", and ahmed mukhtar omar said: "converting phonemes are either identical or partially identical." the symmetry or symmetry is the union of two things in a species, they are identical, but they do not share a analogy understanding, ]4, p. 26] aristotle considered in his book "public speaking that the goal of the analogy is persuasion, that is, a rhetorical technique that makes speech acceptable in the mind of the recipient, that is, the presence of a dialogue between a sender and a future seeking to create the mind of the latter so that it is able to act [28, p3]. analogy is a central concept in human perception and creative thinking [27, p22 / 24]. they refer to clear relationships between theoretical logic, cognitive processes, long-term memory recall, classification and relationships between analogy and analogy. for example, [17, p34] is displayed on the coordinate design area where the axes are: "common relationships" and "attributes" [22, p12[ the analogy of the spatial domain of metaphor and metaphor is as follows: "analogy elements and structural and structural analogy, while metaphors extend the spectrum of relational analogy at one end, and the analogy appearance on the other" theoretical logic, cognitive processes and memory retrieval are the result of structural and structural relationships and common characteristics in order to diversify and enrich semantic and persuasive levels through the centrality of cognition and creative thinking. 2.1.1. types of analogy: the idea of analogy in the creation and progress of science, whether through induction or extrapolation, contributed to the formation of general laws resulting from the recognition of symmetry in relations between successive objects. analogy applications are widely used in the theory of analogy and are used in analogy synthesis. the qualities required. dr. taha abdulrahman summed it up in four categories: the totality analogy between the two: the two things that share all the attributes: what is required of them, and what is permissible and what is impossible. partial analogy: it establishes between the two things which share the same characteristics, so that one thing has the same characteristics as another, and another recipe for the departure of the other, [the principle of participation in certain qualities without limitation.] the general self-analogy: is established between the two ideals, ie, the two things that share the subjective [or psychological] characteristics without the occasional (or moral) qualities. according to taha abdul rahman 4, the speakers come out of the selfattributes that are based on the analogy, what they call the [characteristics of the public] such as occurrence and presence and the ground, because such qualities may be shared by differentiated. self-analogy: it is established between the two extremes, that is, between the two things that share the most characteristic characteristics. these characteristics necessitate the identification of the relations between them, with their order, making some more general, some middle, some more specific. the most important characteristics are those that bind all qualities and are not binding on others, and the middle is the one that binds others and is required of others. the most common ones are those that are binding on others and are not necessary from others. [14, p. 15-47], prudent is the most powerful source of creative ideas in architectural design. and distinguished three analogy categories: the morphological-visual-structural-philosophical analogy, together with philippe steadman 2008, which identified two distinct types of interpretation on the two analogy: visual [appearance composition] first to [directly analogy] [mirror] and indirectly indirect [placing the object in place] [38, p201.] 2.2. thinking and analogy: thinking is one of the most difficult processes in which the human mind has to understand and thus define. the reason why man's thought in many of the physical and vital processes around him is trying to understand some 40 sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 of them and still tries to understand others. in these cases he thinks of something outside of him when you are at the top of a mountain, knowing who is at the bottom of the mountain is better than knowing you and your ability to gather more information about it, trying to understand the thinking process employs the thinking tool to understand itself and to understand what it needs to look at from outside or above it [13, p. 2], the intellectual source is the process of higher biological directed in the brain, shared by the implementation of the brain thinking tool which deals with some of the stored and received by the moment of thinking of information and experiences, convictions and trends, and participate in the implementation of nerve impulses and electrical currents, the treatment is in a kind of lower processes such as comparison, contrast, analysis, synthesis, classification and arrangement and express the human feelings in body language has is expressed by a word, a book, or a sermon, and may turn into behavior that is opposed to systematic or planned behavior aimed at reaching the result that led to the process of thinking. thinking is the source of every human act. it is an expression of a living experience, a language that enables the expression of emotions and selfconsciousness. it does not matter if it is joyful, sad, tender or direct, thin or violent, romantic or funny. to convey something to others is to express a living experience, in terms of its ability to explore its paradoxes and dilemmas, feeding it back to experience, to example, to question and to think, if we find a new role to think about what is the engine of philosophical consideration [12, p. 28] , the concept of analogy and analogyical reasoning builds a bridge between unfamiliar concepts and earlier information for learners to help them create a new knowledge structure specific to abstract concepts. any problem that seems strange and unfamiliar can be understood if it is thought through analogy and representation. helps to explain the highly abstract relationships such as the atom and the solar system. it also facilitates learning by building relationships between the interactions. thus, the interactions are an effective tool in facilitating the process of building the knowledge of the individual on the basis of concepts that flag and previous knowledge available. 3. the concept of analogyical reasoning : the term symmetry is used to illustrate a particular idea, problem, or solution by finding an example of a common problem in order to arrive at a suggested qualitative description of the problem of these interrelated ideas. this helps to test the problem more clearly by identifying analogy elements among analogy models through which access to a new style of solution. abdalmutallab shows that 80% of the innovative ideas originated in analogyical reasoning. the writers borrow their ideas from life, events, television, advertisements, children and headings, as we see in mechanical systems [10, p. 10] reference to the source is the objective of the analogy, and analogyical reasoning generally assumes that if two states or objects are known to be identical in some respects, they are likely to be identical to each other. the analogyical reasoning between the terms is based on an understanding of these terms,the relationship between terms together and analogyical reasoning is a reflection of two entities [source, rule and objective] by comparing them by finding analogy and dealing with one goal in relation to the way they deal with another source [source or base] [18, p13], baker stated that the problems can be solved by three systems: inductive, inductive, and analogy reasoning; analogyical reasoning is one of the strategies used in problem solving where it takes a solution from the source and transfers it to the target [problem] using analogy may be a strategy or context by connecting the familiar to uncommon [new problem] [16, p70], it is observed that analogyical reasoning is to think of two entities to arrive at a suggested qualitative description of these ideas that are connected to the production of innovative ideas and to find aspects of symmetry and dealing with the goal where problems can be solved by analogy systems of analogyical reasoning 3.1. analogy sources of analogyical reasoning: the architectural designer and critic is concerned both with the ideas and the architectural forms designed, as the architectural forms are different from each other in the extent to which they are achieved for certain purposes, which is a standard for the period in which this effect was born or that , these standards are crystallized and determined by the theory of architecture, some of them considered the [good] architectural form to express their assigned function, and many forms were characterized at the beginning of the twentieth century according to this criterion some of them considered the architectural form as a text analogy to the language text that carries a coded message using previously known architectural elements and used in the writing of these texts. new architectural forms were also distinguished according to this criterion. some of them focused on the potential of the building material in shaping its forms architectural formation which: (analogys: which is based on the relationship between craft, metaphors: which is based on innovative relations between the two, essences: which are based on determining the origin of phenomena and the most fundamental aspects of functional needs, concepts programmatic: which is based on operational functional needs ,ideals: which depend on universe values]23,p223,253]. 3.2. analogy thinking and design process: the design process goes through the flow of information along with ideas but at different levels and design is a set of ideas and events and the architectural mind searches in memory to find elements and components that match the needs of the problem , and compensate for the lack of information through the various references, the designer can achieve a wide range of goals through the design idea, and different projects vary these objectives or change the value resulting from the achievement and hence show the levels of application of the architectural idea as follows:  function level.  the space level.  movement level.  level of formation.  the level of relationship with the environment. the talk of a classification of ideas may be difficult as the way of thinking and expressing it is clearly different from one person to another, but there is a link between each group of ideas that makes it a doctrine and direction analogy to it in its general framework and characteristics are driven to say that this idea follows him or not and here the relationship of analogy to thinking of three levels [formal, functional and structural] is evident at the level of architectural design. the types of architectural ideas may be classified as follows: the planning idea: this idea is reflected in the overall planning of the project as a whole to appear in the buildings and coordination of the relationship and bonding of the blocks, usually in multi-building projects or projects that require open areas with specific spaces and this idea is a general idea mostly include type or more of the following ideas mentioned. technical idea: this idea deals with the core of the design problem directly through its solution in a purely technical manner, and using the means of sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 41 technology and innovations. it should be noted here that it can not be said that this idea is a design idea unless it affects the design directly, the goal is to design a product that solves a problem, not a problem for any design, but it is ultimately dry and expansive so it is also best to combine it with another kind of ideas to give it a soul. the philosophical concept: the philosophical approach is one of the most powerful intellectual schools and has the ability to convey general concepts. at the same time, it may lead to disdain of the idea, especially when the philosophy becomes a novel with several chapters. the strength of this type of ideas is reinforced by the multiplicity of ideas and their links with the project and its components. it is also necessary to mention here the need to move away from the surface in the translation of the idea and the search for the dimensional dimensions of its contents [35, p30]. inspirational idea: each line of the lines gives a different impression in the brain and when combined together in a stereoscopic shape, a general suggestion is formed that translates into the brain in a certain way (happiness, hope, sadness, balance, disturbance, etc.). aspects of the project to search for the desired inspiration and starting from the same project, where it analyzes the components of the project and express them in forms of relevance. it can be said here that this type of ideas is often used with another type, because it does not ensure the delivery of the side of inspiration in a uniform manner for all. the symbolic idea: it is very analogy to the idea of inspiration, but does not depend on the meaning inspired by the line and the interpreter of the brain receptor, but depends on the link of the shape of the project through some of the usual symbols such as the food dish link to the restaurant, or bank paper bank and so on. in primary forms or lines should not reflect the basic form of the element but symbolize it. impressionist idea: it is a very superficial idea and a lot of criticism, and it can be said that it does not require a high amount of knowledge and does not need to develop where a project-related element is captured and falls on the project's current form as it is, it is not clear here that this type of thinking has failed. abstract idea: here the designer to quote a specific element and be of a symbolic or inspirational nature, but not only contrary to the design, but enters the process of abstraction to finally get a new form serves the distribution of blocks required according to the studies of the project, and the strength of this idea if the introduction the philosophical aspect of the process of abstraction itself. structural idea: the construction idea is often derived from the abstraction of a structure in nature, used to solve the problem of construction but in a unique way, it can be argued that this idea is a branch of the abstract idea [34, p2] show in fig. 1. 3.2.1. analogy thinking and design construction: the architectural form is subject to many different elements and trends that control the process of its production. these elements can be classified as functional or structural dimensions. some of them may also be included under the influence of psychological factors and values of society with conceptual dimensions related to the person's ideas and the nature of the influences, there are four major features in which the architectural form can be seen as presented by ahu gurler in a paper entitled "domineering and promise patterns". these features are:  formal features.  functional features functional aspects.  structural features.  psychosocial features(socio-psychological aspects) [24, p99] . technical idea the planning idea inspirational idea impressionist idea abstract idea structural idea figure 1. shows the types of architectural ideas (40) analogy thinking and formal construction: the architectural form has elements that the product of architecture can deal with in order to understand the different production formula in order to avoid many of the negatives resulting from the exclusion of this intellectual stage from thinking. the form has two important characteristics. the first is to determine the design approach that architecture takes to achieve its products, by adding another function [expressive, symbolic, and semantic] to the products, in the case of the analogy of the noun in the determinants and function, the products from the source is more acceptable and performance than the products that achieves the function of protection only. it is clear that the main engine is the intellectual or conceptual dimension. the idea includes all that is related to mental activity and what includes the arrangement of things that lead to unknown as a tool for thinking [1, p. 55], 42 sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 or is the intellectual content and the sum of the ideas of the human mind as a whole takes its privacy from the contact with the cultural and social environment that we deal with. the way of thinking contributes to several facts that are part of reality [6, p. 12] the individual in his life m life itself as long as it is still alive and the human is only a series of series of ideas turn to human behavior, including the crystallization of human personality, through the crystallization of these ideas crystallize personality, the ideas rely on those generators that the mind when receiving an event where the event is crystallized in the unconscious to an idea in the subconscious until the emergence of a new idea or a certain event in the new appearance, and the human is only a set of ideas that control the behavior, and analytical psychology on the principle of practical analysis of psychological ideas and acquired in the psychological and traumatic event through which the p z that idea generated by psychological stress, the mind and heart can be synonymous in the sense of ideas and feelings is a mix between the heart and mind [13, p. 23]. analogy thinking and functional construction: it is about functional purposes during the process of analogyical reasoning, as it matches the suitability of animals and plants in their environment. it is linked to the performance of the analogy process and its anatomical analogies related to the state of analogy in function but necessarily analogy in structure and anatomical position between different organisms and architecture. [42, p45] is in contrast to the symmetry that points to the analogies between organisms as structures and anatomy, structures that appear symmetry are called homogeneous structures may be analogy in structure and appearance but perform different functions. on the other hand, structures analogy to analogy structures and analogy structures and homogeneous structures of evolutionary origin are called anatomical analogies in which the anatomical structures [or behavioral qualities] exist between two objects not connected to the same functions and in gothic architecture are clearly observed the use of analogy parts of anatomical organisms, and of analogy kinds of environmental analogies examine the relationship between some organic body functions and image or form; and to show a analogy relationship apply between some functions of buildings, and their forms. these were somewhat general to the architectural functions, applicable to buildings of almost all kinds such as judging usable space, their relation to occupied site space retention or heat loss, and acceptance of daylight affecting the surface area of walls and ceiling. the forms of buildings correspond to each other [43, p7], and may be to express specific functions that may be related to the size, shapes and relative disposal of rooms, the placement of doors, windows, and playgrounds. with these specialized uses include: theaters, railway stations, office buildings and at the same time [26, p54]. analogy thinking and structural construction: these are positive and negative relationships: the positive is the presence of the meaning or the information of the thing and the negative is the meaning that is formed through the new relationships that are formed by any information added to it through its presence in the new context and relations and in the case of borrowing a certain form and design of the idea on the basis of that is referred to the forces of tension and pressure in the human body sometimes indicates that the depth of the analogy between the source and the objective, or the nature of symmetry taken in the process of emitter of, the extent of the analogies related to the depth of the source and target [22, p23[, the production of the architectural form is done according to general and vague intellectual conditions that include the behavior of the architect and what should be the architecture on the other hand. this process may be characterized by different concepts and different ideologies such as the spirit of the place or the spirit of the times or the higher types and other concepts that do not represent themselves clear things may differ in terms of understanding and application from time to time and from place to place according to the architect understanding of the role of the cultural and social environment and his theoretical and intellectual commitment to life. 4. literature review: after the previous were put forward concepts related to analogue thinking and analogy in several aspects will be in this axis to complete the launch of specialized studies for the purpose of using them with the previous axes in the design of the research will be clarified through the following scheme: table 1. shows the previous studies and the most important vocabulary to which they were addressed object of the study what the study addressed studying design is an effectiveness that depends on a set of scenes related to the process of thinking the study dealt with the process of the effectiveness of architectural design, with a series of scenes or successive intellectual snapshots, and away from the doctrine of correlative psychology, which adopts a method based on the interpretation of the process of thinking about the associations between the concepts and the behavioral doctrine that establishes a catalyst model, the study determines the possibilities of the intellectual production of the designer through a process of rotation that includes the evaluation and evaluation of the big idea. the study focuses on the fact that the intellectual production mechanisms of the designer often take the form of readers and analogy rowe, p., g., 1987 the difference between the use of analogue thinking between the novice designer and the expert based on knowledge and mental jumps to produce analogies the study presents the differences of architectural products resulting from the use of analogue thinking between the stylist and the expert. it consists of four functions: examples of the source of the evaluation, selection of the source of the field and design of a bus station. the results indicate significant differences among the participants regarding the safety of classifications. the results showed a significant relationship between the level of experience and selection of participants from the source categories, the reasons cited for their selection, the type of analogy that was created between the source and the objective and concluded that experts prefer "mental jumps" while students prefer to copy literally sources. design problem the results of the pilot study are reported to have investigated whether students of different levels of architectural education and expert architects differ from each other in the way they are used analogy to ozgu ozkan and fehmi dogan, 2012 sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 43 a particular design task and goals related to symmetry, which arise between sources and target ranges and compared with other analogy research the relationship between analogy understanding or misunderstanding and its relation to design by comparing the analogies between two concepts. extraction and transfer of knowledge from one concept to another the study presents the correlation between analogy understanding or lack of understanding and its relation to design by comparing the analogies between two concepts. extraction and transfer of knowledge from one concept to another allows designers to develop design concepts that analogue reasoning plays a key role in creative design, and then transfer analogy strategies to develop design solutions. the research objective is to gain a better understanding of the process of analogue thinking in nature-inspired biomimetic forms. the inductive approach to the perception of analogue thinking behind biological design and the description of the biological text have been used. phenomena that contain causal relationships are more likely to be useful for analogies of design problems. causal relationships often explain how functions are achieved by behaviors. she focused on the analogies between two concepts and analogue reasoning through simulated forms of nature and the use of an inductive approach to the perception of analogue thinking behind dynamic design. through creative thought, between the functions of objects and take advantage of the system inherent in the biodesign principle of growth and its use in architecture an inductive approachhyunmin cheong2014 the use of previous design cases and their solutions for planning the installation of new designs a popular way to use experience to solve new problems is to develop an expert system that contains an appropriate representation of relevant expertise in the form of inference which becomes the basis of inspiration rules and touched on two analogy types of transformative analogy transformations and thought steps in building the past solutions can be retrieved this paper presents a methodology for identifying relevant design elements for compiling new structural designs using previous design situations and corresponding solutions. the study is a reflection of the observation that engineers use relevant experience when solving new problems, the methodology is the application of transformational analogy, a form of analogue thinking has been developed a model system to implement the methodology, the utilization of the expert knowledge-based system techniques. where the experience and knowledge of the designer as the resource faces a new design task, experience that can only be accumulated over a long period of practice. this paper proposes a methodology using previous design situations and solutions to plan the installation of new designs. a popular way to use experience to solve new problems is to develop an expert system that contains an appropriate representation of relevant expertise in the form of inference that becomes the basis of inspiration rules and refers to two analogy types of analogy transformational derivational analogies and steps thinking about building the past the solutions can be retrieved and modified in order to build derivative paths towards solutions to new problems. the transformative analogy concerns only the definitions and solutions of the problem and ignores the thinking processes that lead to these solutions in this the situation requires a new storage solution to the problem in memory for later use mary lou maher2015 design is likewise the richest source for creating analogy ideas on the design process in the academic milieu through a historical view indicating that man over the ages uses the formative manipulations the study examined the effect of analogies on the design process in the academic milieu through a historical view indicating that man over the ages uses the formative manipulations even implicitly in his artistic and architectural activity for a motive that may be religious, symbolic or mental, and may be unconscious [p. 7.2] the richest source for creating ideas in architecture has been used by many architects at one time or another in their practical lives as well as the psychological significance of the pleasure they receive [p. 9]. the study also examines the importance of the designer's self-role in the process of creating the architectural form to stimulate and generate ideas and derive architectural forms from the other side [p. 14]. the analogy study deals with the design products of the architectural study students as one of the important design strategies in the architectural design process, composition and derivation [p. 10], where the study dealt with the relationship between the designer and the analogy and explain the causes and sources of analogy safo ,2008 analogy represents the process of linking cases from one domain [source] to another [goal] by establishing relationships or representations of designs that share at least one function or behavior the study examined the concept of analogy as the process of linking cases from one domain to the other [objective] by establishing relationships or representations of designs that share at least one function or behavior [p1]. the study also focused on analogue correlation and retrieval of human cognition how the problem occurs where previous research has shown that multiple representations facilitate logical reasoning by retrieving effective manipulations and the novel stored in long-term designers' memory ]p12], and many examples of innovative systems and products based on analogy can be found in practice such as products inspired by nature and living organisms [p3]. this study has shown methods and methods such as design, analogy techniques, and the need for methods to understand creative cognition in innovation. the study also linsey—2014 44 sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 after looking at a range of architectural ideas and exploring the most important concepts and in-depth aspects that were put forward in the previous axes, the research reached the most important aspects of the concept which established the conceptual framework for the research problem. a group of vocabulary, the mechanisms of employing analogue thinking: [mechanisms of functional and conceptual intellectual systems, mechanisms of formal and structural physical systems] and as in table 2. include: emphasized the preference to refer to different fields of knowledge, characteristics, experiences, difficulty in networking ]p5] the study dealt with design methods by means of analogy and sources of inspiration. they differ in form and answer direct questions that allow exploration of analogy categories with inspiration from the natural world and development of analogy solutions, abstractions of functional models and flows and explore analogy areas by redesigning the problem. sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 45 5. practical study: after reviewing the knowledge presented to the strategy of analogue thinking based on thought and drawing the comprehensive theoretical framework of the strategy and defining its vocabulary, the basic requirements for the application of the practical study, which represents the second stage of the solution of the research problem, which include the selection of the vocabulary of application and the formulation of hypotheses, to select the methods of measuring the variables and the method of measurement, to apply the vocabulary of the frame to the selected samples and to analyze the data. it is applied to a set of samples chosen for the reasons the comprehensiveness of the vocabulary and its relation to the process of design and the creation of architectural products, the impact of these a variable directly on the architectural products, most studies took those a variable as a source for the creation of architectural products, containing these a variable on the values and indicators detailed to ensure the ease of measurement and accuracy. the hypotheses of research are represented by [analogic thinking is a fundamental and analogy part of a strategy, the multiple analogies that support the same result make the argument stronger, the more analogy the object becomes. the more powerful the products is, the more analogy [ . table 3 shows the description of case studies: the project / city of arts and sciences sample code designer / felix candela site / spain b definition of description the city of the arts and sciences in valencia or valencia in spain, specifically on the banks of the river toria or can be said in the course of the river itself caused severe floods changed the course of the river in 1957, and was exploited the rest of the area to build this dazzling city, arts and sciences by the end of 1994 to 2004, and then continued to build until the city now covers an area of 350 thousand km for the engineers santiago calatrava, felix candela [9, p. 3], the most important buildings are [eye knowledge] the glass building, if you look at it will give you the first glance that it was appointed the idea that the composition of what is designed well and suitable for its purpose will be absolutely beautiful through its suitability. that purpose, with its expressive, symbolic and aesthetic aspects and values, the idea was similar to that of man. man is a social being that includes society and society. he is the one who brings about the reconstruction of the land. from ancient times until today, man is a source of similarity and consideration of man. on its body and members, but extends to the understanding of the laws inherent in it as an object with a physical body and devices and modes of 3d, [29, p2-3] and will symbolize the sample with the symbol b. the project / kauffman center sample code designer / safdie architects site / kansas city c definition of description there is a pair of shell-like shapes containing two halls for the performing arts center in kansas by architect moshe safdie of safdie architecture. the kaufmann center is made up of stainless steel plates. the idea of the project is taken from the sound engineering as it is not taken from the shape the sound waves are transmitted through the material and the form of sound waves in acoustic physics, where the wave is spread in liquids and gases as a longitudinal wave and it is also in the air, for example, the sound spreads in the air in such a way that the pressure of the air periodically, and so on. therefore, the idea of similarity with the method of transmission of sound waves and in line with the nature of the project was used as a formality analogy by the use of similar mechanisms intellectually and formally depending on the sources of intellectual similarities and the idea of strings in the construction of the structure where the effect of the idea is observed at the level formal, functional and structural, and will symbolize the sample with the symbol c [30]. 6. method of measurement: this section specifies the method of measuring the set of variables at the levels related to the theoretical framework, the method of measuring the analytical descriptive measurement method is based on the direct reference to the table according to the selected samples based on the,do not check it if the values are recorded on the table of variables. the data are analyzed in this case by calculating the percentage of each variable according to the formula of statistical thinking (model of thinking): the intellectual model = (variable value / sum of variables) * 100 mi=[xi/sum xi]*100 the variable can be a key in the analogue thinking method depending on the number of signals obtained and which determines the value of the percentage if it refers to: when getting a [3-6] signal any ratio 50% -100 or it is secondary when it gets [0-3] any signal ratio 0% -49%. the measurement form for the application of samples can be explained according to the vocabulary of the theoretical theoretical framework, as shown in table 4: table 4. shows the analysis of the results the main variable secondary variable the subvariable sample c sample a sample b 1 1-1 1-1-1 ● ○ ● 1-1-2 ● ● ○ 1-1-3 ● ● ● 1-1-4 ○ ● ○ 1-1-5 ● ● ● 1-2 1-2-1 ○ ○ ○ 1-2-2 ● ○ ○ 1-2-3 ● ● ○ 1-2-4 ● ● ○ 1-2-5 ● ○ ○ 1-2-6 ● ○ ○ 1-2-7 ● ● ● the project / china tower sample code designer / imb site / china a definition of description tower bank of china [abbreviated boc tower] is one of the most exclusive skyscrapers in hong kong. the building was tallest in hong kong and asia from 1989 to 1992, and was the first building outside the united states breaking the 305 meter barrier [1,000 feet] [37[ the structure adopted in the design of this building is analogy to the bamboo shoots, which symbolize the means of living and prosperity in terms of analogy with plants, not form, but the idea of construction to form the building. what distinguishes forms of nature simulation phenomenon of growth with stability and change to adapt to the environment and represent them in the presence of different formations the appearance and existence of a fixed and balanced relationship is critical, since the truncation of part of the plant may not affect it, and the fractured parts have the ability to grow and not disturb the system. the analogy used is analogy to the intellectual composition using the simulation mechanism of the natural world and symbolizes for the sample with the symbol a . 46 sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 6.1. discussion of results: after applying the theoretical framework and measuring the variables in all the selected projects, the results of the application and verification of the hypotheses of the research will be discussed. in light of the objectives of the study and the hypotheses presented, the results will be analyzed: the mechanisms of employing analogue thinking: it refers to the set of mechanisms and methods used to achieve similarity by thinking, followed by designers to analyze and solve design problems and rates of achievement of these mechanisms are shown in table 5. : table 5. shows the analysis of the results t h e m a in v a r ia b le s e c o n d a r y v a r ia b le t h e s u b v a r ia b le sa m p le a sa m p le b sa m p le c p e r c e n ta g e a c h ie v e d 1 1-1 1-1-1 ● ○ ● 83% 1-1-2 ● ● ○ 66% 1-1-3 ● ● ● 100% 1-1-4 ○ ● ○ 16.6% 1-1-5 ● ● ● 100% percentage achieve 83% 66% 50% 1-2 1-2-1 ○ ○ ○ 33.3% 1-2-2 ● ○ ○ %66 1-2-3 ● ● ○ 50% 1-2-4 ● ● ○ 50% 1-2-5 ● ○ ● 50% 1-2-6 ● ○ ○ 33% 1-2-7 ● ○ ● 50% percentage achieved 85.7% 42.8% 14.2% it is noted that the index of the secondary variable, the mechanisms of conceptual intellectual systems, is achieved in the samples by 65%. the secondary variable achieved by the systems of formal physical systems is achieved in the samples by 42.8%, so 65% and greater than 5 is positive, so it is observed from the logical equation products that the mechanisms of the intellectual systems of the same represent a fundamental part in the achievement of similarity as a strategy in which analogue thinking is achieved by searching for ideas of solutions and relying mainly on the variables [the mechanisms of analogue thinking, the design process in order to achieve the greatest possible number of similarities and thus achieve intellectual similarity. it is noted that sample b is more widely used and used for analogue devices using intellectual analogue thinking mechanisms. this satisfies the hypothesis that [analogue thinking is an integral part of a similar strategy, the same result makes the argument stronger. the more similar objects are achieved, the more powerful and creative the products is. the more similar [the two] the stronger the counterpart. figure 2. shows how much each variable is achieved according to the first variable (the mechanisms of employing analogue thinking as a strategy / (source researcher the mechanics of physical systems are based on a set of visual systems that use metaphor, transcription, simulation and visual analogy to organize and visualize the stages of analogue design. as they work on the transmission and diagnosis of visual features, the mechanisms of similar intellectual systems are an essential part of achieving analogy as a strategy by searching for new solutions from previous ideas and their adoption mainly on the variables intellectual mechanisms that connect the thought of symmetry with the variables of the design process, and this satisfies the hypothesis that analogue thinking is a fundamental and the same as a strategy. 7. conclusions: 1. the analogy is a strategy to solve the design problem and a way of scientific thinking it draws the similarities and differences between the source and the goal to transfer a particular solution or issue from the source to the target, and calls for analogyical reasoning of the three main target in different percentages [solve problems, explain to others, identify problems] the analogy is a linguistic phenomenon, a form of speech to refer two things that are not literally analogy through symbolism and abstraction. they are analogy as a method or means of comparison between analogy and differentiated characteristics of objects and their purpose is to find a reasonable link to far-reaching ideas by associating them with ideas mentally close to the purpose of forming new relationships between the things attentive to the creative side ,analogy means a comparison between analogy and differentiated characteristics of objects and their purpose is to find a reasonable link to far-reaching ideas by associating them with ideas that are close to the mind in order to form new relationships between things as they perform a comparative and comparative work. 2. theoretically correlates theoretically with multiple concepts either in partial or complementary form with the concept or conceptual structure, which indicates diversity in the change of the location of the analogy to other concepts according to the situation and this is in line with the strategic nature of the concept the design using the same as the creator of the creative product depends on the source first refer to the symmetry of any source use of a previous example in another field or a prior knowledge to solve the new problem. 3. the use of analogy on the creation of multi-dependence on the recipient as a way to create associations between historical and modern images and according to their relationships and their links, both stereotyped and formal, impose imposed public frameworks role in symmetry. 4. architectural thought is an important medium in achieving analogy features that ensure the continuity of architecture over time. these features are at the level of all or part of the perception analogy flexibility and the force of stripping the previous positions and restructuring the design within the same scope to achieve the performance of real action and interactive architecture, to reach creativity and uniqueness in the formulation of architecture , analogy thinking is a paradigm shift in the thinking curriculum if it is able to simplify the design process and solve architectural problems by using the previous knowledge to reach the best solutions 5. the concept of analogyical reasoning refers to several mechanisms that are used to explain a principle or idea and related to the relations between logic, knowledge and retrieval based on structural characteristics of a common structural structure that lead to the diversity and enrichment of semantic levels of architectural products. sara r. majeeda , basim h. al-majidia /al-qadisiyah journal for engineering sciences 12 (2019) 038–048 47 6. analogy thinking is important and necessary in the creative processes to produce a design work that leads to real action at the level of perception and innovation is related to the people and their mental memory in the mind as it grows the identity of the architectural products is according to intellectual conditions include the behavior of architect and architecture, on the other hand, place, age, upper patterns, theoretical and intellectual synchronization in life 7. note that man deals with architecture intellectually before the process of production in practice and within two dimensions the first dimension derived from nature starting from the environmental and structural systems and materials available in any virtual environment and the second dimension consists of extracting the values and meanings of this and linked to its activity and products this dimension to the mental system and the nature of mental perception, which deals with the person is aware of the external environment, , the personal environment, and notes that the thought leads to the continuity of civilization as the same person with his ideas and previous experiences to interact spatially with his environment and time between the old and the old .. between the accident and the expected .. so the permanence of the occurrence of great importance in the impact and impact on the community and the recipient of ideas affect the different aspects of the architectural process 8. the analogyical reasoning contains a set of mechanisms to employ it through the reliance on intellectual mechanisms [conceptual, functional], which are based on the system of integrating and matching the architectural ideas implicitly and philosophically and the intellectual borrowing from the previous knowledge in a compatible or opposite way according to the type of analogy required in the architectural products, the analogy system comprises a set of relational s systems that act as a source for deriving the intellectual knowledge in the continuous or continuous sequence of a causal relationship to solve the design problem. 9. analogy thinking is a set of thought mechanisms that are linked to the same through the use of visual imagination, visualization, implicit metaphor, retrieval and intellectual transfer to form a function of the intellectual design process that works to observe, interpret and retrieve from the cognitive memory by taking into account the variables of the functional and behavioral intellectual design process within the structural system integrated work to restore intellectual attitudes, functional, formal and customary. 8. recommendations:  the importance of applying models that lead to analogyical reasoning, most of which were achieved in buildings from different parts of the developed world, which have become among us years of progress that should be shortened so as to keep up with development and achieve the desired future of iraqi architecture.  attention to the study of analogyical reasoning and its applications and knowledge in the brain and interact with them to suit the local reality and transform the architect from the attention to the formal aspect only to think about the deep aspects of the design through which interaction with the recipient.  the establishment of specialized training courses for architects to develop their ability to consider the depth of design and to take advantage of the enormous possibilities and data of analogyical reasoning to achieve uniqueness in architecture.  directing architectural scientific research to study and analyze all mechanisms related to 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[43] http://www.metamia.com/index.php [44] https://www.biology-online.org [45] http://www.metamia.com/index.php http://www.3d2ddesign.com/more_architecture.php?id=39&design=4 http://www.3d2ddesign.com/ https://ar.wikipedia.org/wiki http://kenanaonline.com/users/ahmedkordy/posts/321287 http://www.metamia.com/index.php https://www.biology-online.org/ http://www.metamia.com/index.php al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 68 the use of nanotechnology in construction sector lecture .sada abdalkhaliq hasan college of engineering alqadisya university e mail : sadaalyasri2012@gmail.com received 20 january 2013 accepted 29 december 2013 abstract. the latest researches on nonmaterial’s and nanotechnologies showed the potential use of these materials in deferent fields such as construction, medicine, energy automobile industry, and so on. this is due to the special characteristics of materials at the nano scale. nanotechnology research and product development are actively conducted in industries that manufacture advanced materials. building and construction materials sector are one of the main beneficiaries of these researches. with these applications the materials resistances can be improved and increasing of their durability of concrete ,steel, glass and buffer materials. for example self healing concrete. the largest amount of pollutants are due to the production of various construction materials and to the energy required during their service .the improving of materials by nanotechnology will reduce environmental pollution by reducing the carbon of the building materials, such as cement, and the use of performance thermal insulations will result in efficient use of energy for air conditioning. this paper shows the principles of nanotechnology in the construction sector and explores the current status in the construction industry which is findings from a literature review ,and latest researches in the world . development are also presented to identify the potential benefits for more sustainable construction . key ward : nano material , nanotechnology in civil engineering, nanotechnology in the construction , smart construction, carbon nanotubes . استخدام تكنولوجيا النانو في حقل اإلنشاء م. صدى عبد الخالق حسن سيةجامعة القاد قسم الهندسة المدنية\كلية الهندسة الخالصة البحوث األخيرة للمووا الانووةوو كنواولوايون الاونوو ياوا يةونويوو ا وذه ال وود المووا خول ة وول ةهذلاوو ةاوط ا ولونق ال و ال ن وو واين الانوو ن ور وذناهون خ و اارةوا صانعو السينرات.. الخ كودا ةراع الى خصنئص نلك الموا عا ةجم الانوو ان حوث نواول لوط خعنل خل الصانعو كأوذجا ةوا ةحساو .ا ذ نع ة ط ةوا البانق كا ولنق أن ةوون اة أوم المسذاي ةن ةن ود البحوث ةيث ةوع al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 69 لوووورةوا ةاوط المعنلجوو ود الذ بي نت وسذ يع ان وحسون ة نكةوو المووا كو ةو ةموةوو ,وط ةون الح ةو ال اوند المووا العن لوو ا الدانيو للوووورةا . ان الوميو الوبرى ةن الملوثنت نوون سب اوذند ةهذلف ةووا الباونق كةذ لبونت ال ن وو لهو ةذهن ان المووا المحسوال ذواولوايون الاونوو ل عوا ل الحرارة ةاوذ عاول ,اونقة خول وف ن لط ةن الذلوث البيئل وا و ن ليط الونر ون ةن ةوا البانق ةاط السماا ,من ين ا ذه ا ا ذه ال ال ن و الال ةو لذوييف الهواق . اين الانوو خل ة ط ا ولنق كةذصوا المونووو الحنليوو لذواولوايون الاونوو خول ة وط الذصوايع كالذول نوم لولمانويم نواو عرضخل ودا البحث ر الحنصط لذح ة اةونويو المانخع لالولنق اال,اور الذ و كةذضمن البحث كأة ث البحوث خل العنلم العاور عليهن خل المرااع كاال ينت ا ذ اةو . ونةانني الولمنت : ةوا الانوو نواولواين الانوو خل الها و الم ويو نواولواين الانوو خل االولنق االولنق الد,ل اون ي الونر introduction nanotechnology is a technology that allows us to develop materials and improve it s properties to product new materials”.[15] it is defined as “a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution. one or more external dimensions is in the size range 1 nm-100 nm. in specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution about 50 % may be replaced by a 1 and 50 %..[6] civil engineering is not interested with nanotechnology in construction sector in iraq the thought of civil engineering knowledge should address. the need to provide a broad vision, develop the higherorder skills of future civil engineers. that enable them to adopt emerging technologies, and formulate innovative solutions to complex problems. this research review the achievements of researchers in civil engineering and construction sectors in the world that related with nanotechnology for more sustainable construction . nanomaterials for construction nanotechnology has changed and will continue to change our vision, expectations and abilities to control the materials world. these developments will definitely affect construction and construction materials. recent major achievements include the ability to observe structure at its atomic level and measure the strength and hardness of microscopic and nanoscopic phases of composite materials.[13] because the size of the particles is a critical factor, the material properties significantly differ at the nano scale from that at larger scales. physical phenomena begin to occur differently below the boundary limit: gravity becomes unimportant, electrostatic forces and quantum effects start to prevail. in the same time, the proportion of atoms on the surface increases relative to those inside, creating socalled “nano-effect”. [7] nanotechnology can generate products with many unique characteristics that can improve the current construction materials: lighter and stronger structural composites, low maintenance coatings, better cementations materials, lower thermal transfer rate of fire retardant and insulation, better sound absorption of acoustic absorbers and better reflectivity of glass.[14] when the dimensions of a material are decreased from macro size to nano size, significant changes in electronic conductivity, optical absorption chemical reactivity and mechanical properties occur. with decrease in size, more atoms are located on the surface of the particle. nano powders have a remarkable surface area (fig. 1).the surface area imparts a serious change of surface energy and surface morphology. all these factors alter the basic properties and the chemical reactivity of the nanomaterials the change in properties causes improved catalytic ability,''' tunable wavelength-sensing al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 70 ability' and better-designed pigments and paints with self-cleaning and self-healing nano sized particles have been used.[13] types of nanomaterials for construction 1the carbon nanotubes carbon nano tubes (cnts) are in the family of carbon allotropes. cnts are cylindrical in nature and possess a hardness equivalent to that of diamond. in construction, cnts can be used as nontoxic additives for coatings, leading to better electrical, fire resistant, and optical properties.[27] cnts can be used to produce protective clothing materials because of their flame retardant property. when used as an additive in concrete, cnts improve crack resistance, compared with conventional cements.[20] (fig. 2) showing single-walled carbon nanotube and multi-walled carbon [21] carbon nanotubes are a form of carbon having a cylindrical shape, the name coming from their nanometre diameter. they can be several millimetres in length and can have one “layer” or wall (single walled nanotube) or more than one wall (multi walled nanotube). [14] expected benefits of carbon nanotubes (cnt) reinforced cement/concrete they are one-dimensional nanostructure where: 1-the length-to-diameter ratio exceeds 10,000. 2the young's modulus of cnts can be as high as 1000 gpa ,5 times higher than steel. 3the tensile strength can be up to 63 gpa, 50 times higher than steel. 4they exhibit unique electrical properties, and are efficient conductors of heat. 5much research activities have focused on cnts reinforced polymer or ceramic composite 6exploration of applications of this new material in cement/concrete is underway 7-plain concrete itself is a brittle material that is much stronger in compression than in tension. 8carbon nanotubes may be applied to improve mechanical performance of cement/carbon-nanotube composite 9carbon nanotubes increase the compressive strength of cement mortar specimens and change their electrical properties which can be used for health monitoring and damage detection. 10the addition of small amounts (1%) of carbon nanotubes can improve the mechanical properties of mixture samples of portland cement and water. 11fire resistance of steel structures is often provided by a coating produced by a spray-on cementitious process. nano-cement (made of nanosized particles) has the potential to create a tough, durable, high temperature coatings. this is achieved by the mixing of carbon nanotubes with the cementious material to fabricate fibre composites that can inherit some of the outstanding properties of the nanotubes.[7] the carbon nanotubes have little application as an addition to steel because of their inherent slipperiness, due to the graphitic nature, making them difficult to bind to the bulk material. also, the high temperatures involved in the steel elements production process enhances the vibration of carbon atoms significantly, leading to bond breaking and defects in the nanotubes structure.[15] nano-sensors nano and microelectrical mechanical systems (mems) -sensors have a great potential to be used in concrete structures for quality control and durability monitoring. (to measure concrete density and viscosity, to monitor concrete curing and to measure shrinkage or temperature ,moisture, chlorine concentration, ph, carbon dioxide, stresses, reinforcement corrosion or vibration). nanosensor ranges al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 71 from 10–9 to 10–5 m. these sensors could be embedded into the structure during the construction process and could monitor internal stresses, cracks and other physical forces in the structures during the structures’ life. [14] global markets and technologies for carbon nanotubes the global market for various carbon nanotubes (cnt) grades was $192 million in 2011. in 2012, it is estimated to generate nearly$239 million in revenues, and projected to grow over the next five years at a compound annual growth rate (cagr) of 22.4%, reaching $527 million by 2016. • the global market for multi-walled carbon nanotubes (mwnts) is estimated to rise from $219 million in 2012 to $292 million in 2016,a cagr of 9.1% between 2011 and 2016. • the global market for few-walled carbon nanotubes (fwnts) is estimated to reach $1.8 million in 2012 and $120 million in 2016, a cagr of 131.6% between 2011 and 2016.[16] 2-titanium dioxide nanoparticles (tio2) nano scale tio2 particles in the 10 to 30 nm range are chemically stable, transparent, and lightand weather-resistant. the titanium dioxide nanoparticles are added to concrete to improve its properties. this white pigment is used as an excellent reflective coating. or added to paints, cements and windows for its sterilizing properties. the titanium dioxid breaks down organic pollutants, volatile organic compounds and bacterial membranes through powerful photocatalytic reactions, reducing air pollutants when it’s applied to outdoor surfaces. being hydrophilic gives self cleaning properties to surfaces to which it is applied, because the rain water is attracted to the surface and forms sheets which collect the pollutants and dirt particles previously broken down and washes them off. the resulting concrete surface has a white colour that retains its whiteness very effectively .[25]. nano-tio2 coatings can also be applied to building exteriors to prevent sticking of pollutants, and thus reduce a facility’s maintenance costs.[2] it can also be used as a coating material on roadways to capture and break down organic and inorganic air pollutants by a photocatalytic process. [27] the use of tio2 nanoparticles to glasses leads to so-called self cleaning technology. due to the nanoparticles photocatalytic reactions, the organic pollutants, volatile organic compounds and bacterial membranes are decomposed. as well, tio2 being hydrophilic, his attraction to water forms drops which then wash off the dirt particles decomposed in the previous process. current nano-tio2 production levels have reached approximately 4 million metric tons at a price of approximately $45/kg to $50/kg versus $2.5/kg for conventional tio2. small production volumes and high cost remain the main barriers to the use of nano-tio2.[25],[12] 3silicon dioxide nanoparticles (sio2) nano-sio2 has been found to improve concrete workability and strength, to increase resistance to water penetration, and decreases the setting time of mortar when compared with silica fume (microsilica) and reduces bleeding water and segregation by the improvement of the cohesiveness and to help control the leaching of calcium, which is closely associated with various types of concrete degradation. nano-sio2, additionally, was shown to accelerate the hydration reactions of both c3s and an ash–cement mortar as a result of the large and highly reactive surface of the nanoparticles. nano-sio2 was found to be more efficient in enhancing strength than silica fume. nano-sio2 has been found to increase the compressive strength of concretes containing large fly ash volume at early age, by filling the pores between large fly ash and cement particles by accelerate the hydration reactions of al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 72 both c3s and an ash–cement mortar as a result of the large and highly reactive surface of the nanoparticles.[23],[1] another application of silica is based products for transparent insulation, which leads to the possibility of super-insulating windows. microor nano electro mechanical systems offer the possibility of monitoring and controlling the internal environment of buildings and this could lead to energy savings. fire-protective glass is obtained using (sio2) nanoparticles as a clear interlayer sandwiched between two glass panels which turns into a rigid and opaque fire shield when is heated .highly water repellent coatings incorporating silica and alumina nanoparticles and hydrophobic polymers are proper to be used for wood.[7] the icing chemicals could penetrate concrete’s porous structure and oxidize the reinforcing steel and cause cracking and deterioration to the structure. the addition of nanoscale silica fume operates at a nanoscale and can improve durability of concrete structures exposed to the-icing salts (fig. 3) showing silica fume 10nm [10]. self-cleaning nano-coating by cilica lotus leaves have a fine surface with wax crystals of around 1 nm in diameter .the contact area between the water and surface is reduced to only 2-3% of the droplet-covered surface , dirt and grime can be collected by water drops and rinses off nanotechnology is being used to mimic the lotus leaf surface and create new painting or coating [10], [27] (fig. 4) showing non treated surface and treated surface with silica nano particles , the new development in science & technology has allowed using the latest nano technology to produce eco-friendly organo-silicon products to waterproof practically in waterproofing building materials. 4 -zinc oxide nanoparticles (zno) zno is a unique material that has a diverse family of nanostructures such as nanocombs, nanorings, nanohelixes, nanobows, nanobelts, nanowires, and nanocages and exhibited semiconducting, piezoelectric, and pyroelectric multiple properties furthermore, zno one dimensional (1d) nanostructures combine remarkable properties such as wide band gap, high surface area to volume ratio, high catalytic efficiency, non-toxicity, biocompatibility, chemical stability and strong adsorption ability due to the high isoelectric point . moreover zno is bio-safe and having high ionic bonding (60%), while being insoluble at biological ph [5]. zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. it is added into various materials and products,including plastics, ceramics, glass, cement, rubber, paints, adhesive, sealants,pigments, fire retardants. used for concrete manufacturing, zno improves the processing time and the resistance of concrete against water.[3] 5aluminum oxide nanoparticles (al2o3) the addition of nano-al2o3 of high purity improves the characteristics of concretes, in terms of higher split tensile and flexural strength. the cement could be advantageously replaced in the concrete mixture with nano-al2o3 particles up to maximum limit of 2.0% with average particle sizes of 15 nm, the optimal level of nanoal2o3 particles content being achieved with 1.0% replacement.[17] 6cuo nanoparticles cuo nanoparticles with an average particle size of 15 nm were added to self-compacting concrete and various properties of the specimens were measured cuo nanoparticles are able to improve the compressive strength of self-compacting concrete and reverse the negative effects of superplasticizer on compressive strength of the specimens.[17] 7metals and elements nanoparticles al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 73 the addition of copper nanoparticles reduces the surface unevenness of steel which then limits the number of stress risers and hence fatigue cracking,leading to increased safety, less need for monitoring and more efficient materials use in construction subjected to fatigue issues [15]. vanadium and molybdenum nanoparticles improve the delayed fracture problems associated with high strength bolts, reducing the effects of hydrogen embrittlement and improving the steel micro-structure. the addition of nanoparticles of magnesium and calcium leads to an increase in weld toughness. the nanosilver will affect, in contact with bacteria, viruses and fungi, the cellular metabolism and inhibit cells growth. the nanosilver inhibits multiplication and growth of bacteria and fungi, which causes infection, odour, itchiness and sores. the core technology of nanosilver is the ability to produce particles as small as possible and to distribute these particles very uniformly. when the nanoparticles are coated on the surface of any material, the surface area is increasing several million times than the normal silver foil. [26] tungsten trioxide(wo3) has been employed in the production of electro chromic windows, or smart windows. these windows are electrically switch able glass that change light transmission properties with an applied voltage. this allows the user to tint their windows, changing the amount of heat or light passing through.[7] 8-nano-zro2 zirconia ceramics have been largely used because of their chemical and physical properties, such as excellent chemical resistance, high refractoriness and ionic conductivity.[9] it is possible to add nanozro2 of a high purity (99.9%) and a high blaine fineness value (60 m2/g) in order to improve the characteristics of cement mortars the nano-zro2 particles blended concrete had higher split tensile and flexural strength compare to that of the concrete without nano-zro2 particles. it is found that the cement could be advantageously replaced with nano-zro2 particles up to maximum limit of 2.0% with average particle sizes of 15 nm. although, the optimal level of nano-zro2 particles content was achieved with 1.0% replacement. however, the split tensile strength of the concrete could be improved by using more suitable reinforcements such as needle type nanoparticles.[18],[24] nano technology and self healing concrete experimentation is also underway on self-healing concrete. when self-healing concrete cracks, embedded microcapsules rupture and release a healing agent into the damaged region through capillary action. the released healing agent contacts an embedded catalyst, polymerizing to bond the crack face closed. in fracture tests, self-healed composites recovered as much as 75 percent of their original strength. they could increase the life of structural components by as much as two or three times. when cracks form in this self-healing concrete, they rupture microcapsules, releasing a healing agent which then contacts a catalyst, triggering polymerization that bonds the crack closed .that is shown in( fig .5 )[10],[19] nanotechnology and wood carbon nanotubes are a new discovery, whereas wood is an ancient material which has been used since the dawn of civilization. however, perhaps not surprisingly given nature’s evolutionary process, wood is also composed of nanotubes or “nano fibrils”; namely, lignocelluloses (woody tissue) elements which are twice as strong as nano fibrils would lead to a new paradigm in sustainable construction as both the production and use would be part of a renewable cycle. some developers have speculated that building functionality onto lignocellulosic surfaces at the nano scale could open new opportunities for such things as self-sterilizing surfaces, internal self-repair, and electronic lignocelluloses devices. due to its natural origins, wood is leading the way in cross-disciplinary research and modelling techniques. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 74 firstly, basf have developed a highly water repellent coating based on the actions of the lotus leaf as a result of the incorporation of silica and alumina nano particles and hydrophobic polymers. and, secondly, mechanical studies of bones have been adapted to model wood, for instance in the drying process.[24],[22] nanotechnology on the environment a good example illustrating the impact of nanotechnology on the environment is the cement production process. at an annual production rate of 2.35 billion tons, cement manufacturing is responsible for large amounts of carbon dioxide (co2) emissions and pollutants. research expects that by reducing 10% of co2 in cement production facilities could accomplish 20% of the goal identified in the kyoto protocol for example, additives such as belite, calcium sulfo-aluminate and calcium alumino-ferrite . have been found to reduce the co2 emissions by nearly 25% in the production phase.[19],[4],[8] .nanotechnology, the manipulation of matter at the molecular scale, is bringing new materials and new possibilities to industries as diverse as electronics, medicine, energy and aeronautics. our ability to design new materials from the bottom up is impacting the building industry as well. new materials and products based on nanotechnology can be found in building insulation, coatings, and solar technologies. work now underway in nanotech labs will soon result in new products for lighting, structures, and energy. in the building industry, nanotechnology has already brought to market self-cleaning windows, smog-eating concrete, and many other advances. but these advances and currently available products are minor compared to those incubating in the world’s nanotech labs today. there, work is underway on illuminating walls that change colour with the flip of a switch, nanocomposites as thin as glass yet capable of supporting entire buildings, and photosynthetic surfaces making any building facade a source of free energy.[24],[7] some manufactured nanomaterials have already been in use for a long time (e.g., carbon black, tio2) showing low toxicity. therefore, the hypothesis that smaller means more reactive, and thus more toxic, cannot be substantiated by the published data. in this respect nanomaterials are similar to normal chemicals /substances in that some may be toxic and some may not. as there is not yet a generally applicable paradigm for nanomaterial hazard identification, a case-by-case approach for the risk assessment of nanomaterials is still warranted.[ 11] mor sustainable construction increased consumption of raw materials in the construction industry affects the environment, economy, and society. lack of raw materials causes prices to increase.the use of nano-based materials can reduce the amount of raw or bulk materials needed to achieve or surpass similar strength and durability properties. a good example illustrating the impact of nanotechnology on the environment is the cement production process. at an annual production rate of 2.35 billion tons, cement manufacturing is responsible for large amounts of carbon dioxide (co2) emissions and pollutants. research expects that by reducing 10% of co2 in cement production facilities could accomplish 20% of the goal identified in the kyoto protocol .[19]. for example ,additives such as belite, calcium sulfo-aluminate and calcium alumino-ferrite [4]. have been found to reduce the co2 emissions by nearly 25% in the production phase.[8] new materials and products based on nanotechnology can be found in building insulation, coatings, and solar technologies. work now underway in nanotech labs will soon result in new products for lighting, structures, and energy. in the building industry, nanotechnology has already brought to market self-cleaning windows, smog-eating concrete, and many other advances. but these advances and currently available products are minor compared to those incubating in the world’s nanotech labs today. there, work is underway on illuminating walls that change colour with the flip of a switch, al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 75 nanocomposites as thin as glass yet capable of supporting entire buildings, and photosynthetic surfaces making any building facade a source of free energy.[24] most of glass in construction is on the exterior surface of buildings and the control of light and heat entering through building glazing is a major sustainability issue. research into nanotechnological solutions to this centres around four different strategies to block light and heat coming in through windows. firstly, thin film coatings are being developed which are spectrally sensitive surface applications for window glass. these have the potential to filter out unwanted infrared frequencies of light (which heat up a room) and reduce the heat gain in buildings, however, these are effectively a passive solution. as an active solution, thermochromic technologies are being studied which react to temperature and provide thermal insulation to give protection from heating whilst maintaining adequate lighting. [15] nanotechnology remains in its pre exploration stage; it is just emerging from fundamental research to the industrial application .therefore, full scale applications, especially in construction, are limited. however, the tremendous potential of nanotechnology to improve the performance of conventional materials and processes is most promising. conclusion nanomaterials and nanotechnologies have attracted considerable scientific interest due to the new potential uses of particles in nanometer scale there are many potential areas where nanotechnology can benefit buildings and construction engineering like its applications in concrete, structural composites, coating materials and in nano-sensors, technologies. work now underway in nanotech labs will soon result in new products for lighting, structures, and energy. in the building industry, nanotechnology has already brought to market self-cleaning windows, smog-eating concrete, and many other advances. the nanotechnology generated products have unique characteristics, and can importance change the requirement and organisation of construction process it could pay enormous rewards in the areas of technological the recent developments in the study and manipulation of materials and processes at the nanoscale offer the great prospect of producing new macro materials, properties and products. but till date, nanotechnology applications and advances in the construction and building materials fields have been uneven. further, in the research process will be studied: the possibility of replacement of steel reinforcements in the reinforced concrete with carbon nanotubes able to take the tensile stresses; the possibility of increasing the durability of concrete using nanomaterials; the development of real time monitoring systems for structural elements using nanomaterials embedded in concrete in order to obtain safer buildings. reference 1ashwani k. rana and shashi b.” significance of nanotechnology in construction engineering, civil engineering & construction review, 78-84, (2011) 2 bolte, g. “innovative building material—reduction of air pollution through ticem.” proc., nanotechnology in construction 3, springer ,berlin heidelberg, 55–61 . (2009). 3broekhuizen f.a, broekhuizen j.c.," nanotehnologia în industria europeană a construcţiilor – stadiul actual al tehnologiei (transl. from english). 2009 page, 7-30, www.efbww.org. 4-basf group. http://www.basf.com . (nov. 1, 2008). al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 76 5 chan o.c., syed m., usman a. , zafar h. ibupotoa, kimleang k. ,omer n. and magnus w. “potentiometric creatinine biosensor based on zno nanowires” , journal of nanoscience letters , © 2011 simplex academic publishers. www.simplex-academic-publishers.com 2012 6european commision “communication from the commission to the european parliament , the consol and the european economic and social committee” brussels, second regulatory review on nanomaterials , 3\.10\2012 7 gheorghe a. “ construcţii. arhitectură nanomaterials and anotechnologies for civil engineering” buletinul institutului politehnic din iaşi, technical university of iaşi, faculty of civil engineering and building service received: may 19, 2011 accepted for publication: august 27, 2011 8 -gartner, e. “industrially interesting approaches to ‘low-co2’ cements.” cem. concrt. research 34(9), page 1489—1498, (2004). 9hee -jin n., dong-seok s., hwan k. , jong-kook l. , “synthesis and crystallization of anisotropic shaped zro2 nanocrystalline powders by hydrothermal process” ,school of materials engineering, seoul national university, seoul,, south korea materials letters 57 (2003) page 2425– 2431. 10 http://www. net \colloquium\nanotechnology –in-civil-engineering.(2012) 11 -http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_023.pdf, p. 52-53 12jochen t, manu v., winfried t.; and jakub f. “ nanotechnology and its impact on construction: bridging the gap between researchers and industry professionals” journal of construction engineering and management © asce / may 2012 page 594604 13konstantin s. and miguel f. g. “ how nanotechnology can change the concrete world” part one of a two-part series american ceramic society bulletin(acs), vol. 84, no. 10 october 2005. 14lee j., mahendra s., alvarez p.,” nanomaterials in the construction industry” a review of their applications and environmental health and safety considerations.acs, 3580-3590 (2010). 15 mann surinder “ nanotechnology and construction” institute of nanotechnology, european naontechnology gateway 31/10/2006 16market research reports and technical publications product catalog november 2012. 17 nazari a., shadi r., sharin r., shamekhi s.f., khademno a.,” al2o3 nanoparticles in concrete “ j. of amer. sci., 6, 4, page 94-97 (2010). department of materials science and engineering, saveh branch, islamic azad. 18nazari a., shadi r., sharin r., shamekhi s.f., khademno a “ embedded zro2 nanoparticles mechanical properties monitoring in cementitious composites “ journal of american science 2010 page 86-89 19-nanowerk. (2007). “green nanotechnology concrete could cut carbon dioxide emissions.” ,[http://www.nanowerk.com] (nov. 13, 2007). http://www.simplex-academic-publishers.com/ al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 77 20national research council. “investments in federal facilities.” report of the national academies, national academies press, washington, dc. (2004) . 21philip w. and deji a. “carbon nanotube and graphene device physics”http//www. amazon.co.uk ,243pages 22 pacheco-torgal .f and said jalali “nanotechnology: advantages and drawbacks in the field of construction and building materials,” (2011), page 582-590 . 23sadrmomtazi a., barzegar a.,” assessment of the effect of nano-sio2 on physical and mechanical properties of self-compacting concrete containing rice husk, ash. sec. internat. conf. on sustain. constr. mater. a. technol., u.p.m., ancona, italy, june 2010, page 3-8. 24-saurav “ application of nanotechnology in building materials” international journal of engineering research and applications (ijera) issn: 22489622 , www.ijera.com, vol. 2, issue5, septemberoctober 2012, page1077-1082. 25-the royal society. (2004). “nanoscience and nanotechnologies: opportunities and uncertainties.” london, http://www.nanotec.org.uk/report/.(mar. 2008). 26 (www.nanosilver.com.my). 27zhu, w.,bartos, p. j. m., and porro, a. “application of nanotechnology in construction: summary of a state of the art report.” mater struct., 37(9), 649–658. (2004). http://www.nanosilver.com.my/ al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 78 fig .1 particle –size and specific –surface-area related to concrete materials [3] single-walled carbon nanotube al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 79 fig .2 single-walled carbon nanotube and multi-walled carbon nanotube [8] fig.3 silica fume 10nm [15] fig. 4 (c) treated surface with silica nanoparticles. (d) water droplet on this surface. [6] al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 80 fig. 5: mechanism of self healing concrete [15] al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 21 modeling the kinetics of hydroxyapatite catalyzed transesterification reaction dr. ali a. jazie al-khaledy department of chemical engineering, college of engineering, university of al-qadissiya, addywania, iraq jazieengineer@yahoo.com received 1 april 2014 accepted 25 november 2014 abstract a bone waste was utilized as a cost effective catalyst for the transesterification of indian mustard oil. this high efficient and low-cost waste catalyst could make the biodiesel production from indian mustard oil competitive with petroleum diesel.the catalysts samples were calcined at different temperatures (800 o c, 900 o c and 1000 o c) for 2 hrs. the samples were characterized by using x-ray diffraction (xrd), fourier transform infrared spectroscopy (ftir) and bet surface area analyzer. a simple model was used to study the kinetics of hydroxyapatite-catalyzed transesterification of mustard oil. the optimum conditions for biodiesel production were (reaction temperature (60 o c), a methanol-tooil molar ratio (20:1) and catalyst amounts (18% based on oil weight). two steps were concluded for the transesterification process, the initial one is the triglyceride (tg) mass transfer controlled region, the second one is the chemical reaction controlled region. the high adsorbed methanol concentration and the lower availability of active specific catalyst surface caused the tg mass transfer controlled region.increasing the catalyst amount in the transesterification process caused increasing both the tg mass transfer and chemical reaction rates.the effect of mixing conditionsin the transesterification process was predicted in the modeling strategy. keywords: modeling, kinetics, mustard oil, transesterification, hydroxyapatite. nomenclature am specific surface of catalyst (m 2 /g) ca concentration of tg in the liquid phase (mol/dm 3 ) cao initial concentration of tg in the liquid phase (mol/dm 3 ) ca,s concentration of tg on the interfacial solid liquid area(mol/dm 3 ) cb concentration of methanol in the liquid phase (mol/dm 3 ) cr concentration of fame in the liquid phase (mol/dm 3 ) c integration constant (1) dp catalyst particle size (m) d molecular diffusion coefficient (m 2 /s) deff effective diffusion coefficient (m 2 /s) k pseudo-first order reaction rate constant (min -1 ) kad methanol adsorption rate constant (min -1 ) kapp apparent process rate constant (min -1 ) mailto:jazieengineer@yahoo.com al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 22 ks,a tg mass transfer coefficient towards catalyst surface activesites (m/min) kmt,a volumetric tg mass transfer coefficient towards the catalystsurface (=ks,a.h .am.mhap/v )(min -1 ) mhap mass of heterogeneous catalyst (g) q the instantaneous concentration of adsorbed methanol(mol/g) qmax the maximal concentration of adsorbed methanol (mol/g) (-ra) rate of tg consumption, (mol/(dm 3 min)) (-rb) rate of methanol consumption (mol/(dm 3 min)) rp catalyst particle radius (m) t time (min) tg content of tg in the fame/oil fraction of the reactionmixture (%) th thiele modulus (l) v volume of the reaction mixture volume (cm 3 ) xa degree of tg conversion (l) greek symbols εp catalyst particle porosity (l) εp catalyst particle tortuosity (l) θ fraction of the catalyst available active specific surface(l) θo fraction of the catalyst available active specific surfacein the initial phase of the transesterification process (l) abbreviations tg triglycerides dg diglycerides mg monoglycerides fame fatty acid methyl esters hap hydroxyapatite catalyst نمذجة حركية تفاعل الترانساسترة المحفزة بواسطة الهيدروكسي اباتايت الخالصة يعتبر. حيوي ديزل الى الهندي الخردل زيت لتحويل الترانساسترة لتفاعل الكلفة واطئ مساعد كعامل استخدمت العظام مخلفات .إن النفطي االصل من الديزل لوقود منافس الحيوي الديزل انتاج جعل في مهم عامل الكلفة واطئ مساعد عامل هكذا استخدام م, نسبة 06تم دراستها بظروف متوسطة ) درجة حرارة (hydroxyapatite) حركية التفاعل المحفز بواسطة العامل المساعد خصائصها دراسة تم المساعدة العوامل نماذج% باالعتماد على وزن الزيت(.21وكمية العامل المساعد 1602االيثانول الى الزيت تتضمن (transesterification) (. الدراسة الحالية بينت إن عمليةxrd, ftir, bet surface area) تقنيات باستخدام عة التفاعل الكيمياوي. إن تحديد انتقال ثم مرحلة سريعة وأخيرا مرحلة محددة بسر (tg ) مرحلة ابتدائية محددة بانتقال الكتلة لل كان سببه قلة توفر المساحة النوعية الفعالة للعامل المساعد نتيجة االمتزاز العالي للميثانول على سطح العامل (tg) المادة لل المتبعة ستراتيجيةاإل .مع زيادة كمية العامل المساعد ازدادهماوسرعة التفاعل الكيمياوي كال (tg) المساعد. انتقال المادة لل .(transesterification) ال عملية على الخلط ظروف تأثير االعتبار رظبن تأخذ العملية لنمذجة al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 23 1. introduction the depletion of fossil fuels in the near future and the increasing environmental impact have stimulated the alternative sources for fossil fuel development.advanced research and development on sustainable energy are important due to concerns over climate change and energy security. biodiesel has considerable production potential as a renewable source of energy. the conventional processes use soluble alkali catalysts that contaminate the biodiesel and glycerol products, and present separation problems. an efficient and clean process is crucial for large scale commercial production. solid catalysts have the potential to eliminate these problems[1].currently, transesterification reaction using basic catalysts is themost extended process to produce biodiesel.metal oxides are the basic heterogeneous catalysts group moststudied. there are several metal oxides that have been studied inbibliography: calcium oxide, magnesium oxide, strontium oxide,mixed oxides and hydrotalcites[2]. the kinetics of catalyzed transesterification reactionhas been studiedpreviously in some studies. the trioleintransesterification catalyzed bymgowas simulated by a three-step eley-rideal type of mechanism withthe methanol adsorption on the catalyst active sites as the ratedeterminingstep[3]. the kinetics of soybean oil transesterification at high temperatures using metal oxide as a catalyst was described by a simple first-order kinetic model with respect to tg [4]or methanol [5].the order of the caoand ca(oh)2catalyzed transesterification with respectto tg changed from zero to one with the reaction progress[6].the hydroxyapatite was found an efficient catalyst for biodiesel production from peanut and rapeseed oils in our previous study [7]. to the best of our knowledge there are no previous studies on the kinetic of hydroxyapatite-catalyzed transesterification reaction. in the present work the hapcatalyzed transesterification of mustard oil was studied at the molar ratio of methanol to oil of 20:1 and 60 o c. the transesterification was catalyzed by hydroxyapatite present in the range from 2% to 18% (based on the oil weight). the present paper provide a kinetic studyof hapcatalyzed transesterification reaction carried out to check the process mechanism and report a simple model for the transesterification process kinetics which did not require complex computations. 2. experimental 2.1 materials and catalyst preparation mustard oil was purchased from local markets.methanol, phosphoric acid were supplied from fisher scientific, india. methyl ester, triolien were obtained from sigma–aldrich, germany. all chemicals used were analytical reagents. bones of goat animal were obtained from slaughter waste. firstly, the bones were crushed into small chips and rinsed several times with hot water to remove impurities and undesirable materials. subsequently, the clean bone chips were dried at 378 k for 24 h in a hot air oven. then, the bone chips were grounded to fine powdered and subjected to additional drying at the same above conditions. after that, the fine bone powder was calcined in the muffle furnace at 900 o c for 2 h under static air.finally, the catalyst powders was stored in dark, wellclosed, glass bottle in a desiccator that contains calcium chlorideand potassium hydroxide pellets. 2.2 catalyst characterizations the crystalline phases of calcinedcatalyst samples were analyzed by x-ray diffraction (xrd). the samples were characterized by n2 adsorption-desorption (micromertics, asap 2020) for their bet surface area, pore volume and pore size. ftir spectra were obtained with ftir (thermo-nicolet 5700 model). the spectra were obtained in the 500–4000 cm −1 region, with a resolution of 4 cm −1 . averages of 32 scans were recorded.the mean catalyst particle diameter was calculated from themean particle perimeter which was determined microphotographically. hap powder (0.025 g) was suspended in al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 24 paraffin oil (1 g) bymeans of a vortex agitator for 3 minutes. the microphotographywas taken by a microscope equipped with a digital camera (moticdigital microscope; magnification: 400 times). 2.3 experimental setup the transesterification reaction was carried out in a batch reactor. a 500 ml three necked round bottom glass flask was used. it had provisions for a water-cooled condenser, thermometer, and mechanical stirrer. the flask was kept inside a water bath with thermostat which maintained the temperature at the desired level. the reaction mixture was stirred at 600, 800, and 1000 rpm for all test runs. the photograph of the experimental set up is given in the fig. 1 2.4 transesterification the oils were heated at 378 k for 1 h in n2-purge to evaporate water and other volatile impurities. heated oils were allowed to cool to room temperature. subsequently, a mixture of methanol and catalyst at a designated amount was added to the oil. each experiment was allowed to continue for a set period of time. the reaction mixture was allowed to cool down and equilibrate which resulted in separation of two layers. the upper layer consisted of methyl esters (biodiesel) and unconverted triglycerides. the lower layer contained glycerol, excess methanol, catalyst and any soap formed during the reaction and possibly some entrained methyl esters. after separation of the two layers by sedimentation the upper methyl esters layer was dried at 378 k for 4 h to remove water content from biodiesel layer. the catalyst was separated from lower layer by centrifugation and filtration. 2.5 testing of vegetable oil and biodiesel (methyl esters) properties in the present work, vegetable oil and methyl esters (biodiesel) were analyzed by ftir (thermonicolet 5700 model). the spectra were obtained in the 500–4000 cm −1 region, with a resolution of 4 cm −1 . averages of 32 scans were recorded using a multi bounce atr. the method developed by giuliano et al.[8] was used for quantitative analysis. the height of absorbance band at wave number 1741 cm −1 was used to calculate the concentration of ester in the biodiesel layer. a calibration curve was obtained by measuring the height of the 1741 cm −1 bands for samples of ester and oil of known compositions (methyl ester and triolien).the composition of the reaction mixture samples was determined byftir. figure 2 shows the ftir spectra of produced biodiesel. from the content of tg (in %) in the biodiesel/oil fraction of the reaction mixture, the conversion degree of tg was calculated using the following equation (eq.(1)): ⁄ (1) where tgois the initial percentage of tg in the biodiesel/oil fraction. the acid, saponification and iodine values were determinedby the aocs official methods [9]. the density and viscosity were measured at 20 o c using a pycnometer and a rotational viscometer.table 1 shows the properties of mustard oil. 3. theory the mustard oil transesterification reaction can be expressed by thefollowing equation (eq. (2)): ↔ (2) al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 25 where t is tg, m is methanol, b is fatty acid methyl esters (fame)and g is glycerol.in the presence of heterogeneous catalysts, the transesterificationreaction is very complex because the reaction mixture is a threephasesystem (oil-methanol-catalyst). besides transesterification, someside reactions occur too, such as saponification of glycerides and methyl esters, as well as neutralization of free fatty acids by analkaline catalyst. the kinetic model is derived byproposing heterogeneous reaction mechanism steps and using the following assumptions [10]: 1. the proposed hap-catalyzed transesterification reaction mechanism is shown in the fig. 3. 2. thereaction mixture is perfectly mixed. 3. methanol adsorption follows pseudo-first order kinetics. 4. the conversion of tg follows the pseudo-first order reactionkinetic. the supercritical and subcritical transesterification reactionof soybean oil with nano-mgo was described by thepseudo-first order reaction kinetics [11]. 5. in the initial reaction period, the glyceride mass transfer rate towards the catalyst surfaceactive sites can influence the overall process rate.the glyceride adsorption rate on the catalyst surface is determined by the glyceride masstransfer rate towards the catalyst surface active sites. 6. the internal diffusion rate does not influence the rate of thetransesterification reaction. 7. the overall process rate is limited by therate of the reaction between a methoxide ion and tg in the later reaction period. 8. the overall process rate do not limited by adesorption rate of transesterification products from the catalystsurface . 9. the neutralization of free fatty acids is ignorable and the saponification reaction is negligible. the heterogeneousreactions occursin multiple complicated different steps. by comparing their rates, the rate-limiting step can be determined.normally, the rate of the methanol adsorption on the catalyst active sitescan be equated to the rate of the methanol concentration increase on thecatalyst surface. the mass balance of methanol on solid catalyst surface includes:  the methanol mass transfer from the bulk of liquid towards the catalyst active sites.  the methanol adsorption on catalytic sites.  the rate of methanol depletion in a bulk phase (the methanol depletion reaction rate is equal to the fame formation rate). the reactant mass transfer coefficient depends on:  the reaction mixture composition.  the reaction temperature.  the agitation speed. the available active specific catalyst particle surface is dependent not only on the specific catalyst particle surface but also on the availability of the active sites for the reactant mass transfer . according to the assumptions (4), (5) and (7) the tg mass transfer rate is equal to the tg. with the reaction progress, the adsorbed methanol concentration decreases on the active catalyst surface and at the same time the fraction of the available active catalyst surface for tg adsorption and the volumetric tg mass transfer coefficient increase. the chemical reaction between the adsorbed molecules of tg and methanol controls the overall process rate (eq. (3))[10]: al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 26 (3) the tg concentration is related to the conversion degree of tg, xa as follows (eq. (4)): ( ) (4) then: ( ) (5) upon integration, the following equation is obtained: ( ) (6) where c is the integration constant. thus, both the mass transfer and the reaction rate follow the first order kinetics with a different rate constant (kapp=kmt,a and kapp= k, respectively). 4. results and discussion 4.1 catalyst characterizations it isseen in the fig. 4that the xrd pattern of calcined animal bone at 900˚c shows sharper peaks, indicating better crystallinity. the average hap catalyst particle size was 2.8 µm. the peak positions for hydroxyapatite (hap) are in good agreement with the jcpds (09-0432) having lattice parameters a = b = 0.942 nm, c = 0.688 nm, and no pattern indicating the presence of impurities was observed when bone was calcined at 900 ˚c. this confirms the hexagonal structure of standard hap. the ftir patterns of fresh and calcined bone at 800 o c, 900 o c and 1000 ˚c are presented in fig. 5. the presences of oh -1 and po4 -3 functional groups were confirmed by ftir spectra. the intensity of the oh -1 stretching band is moderate in the spectra of fresh and calcined animal bone at 800 o c and 1000 o c and high in the spectra of calcined animal bone at 900 o c. it is seen from fig. 5 that the carbonate is removed at 900 o c.the bet surface area of catalyst synthesized from waste animal bone at 900 ˚c was 90.65 m 2 g -1 . this is higher than that of other two catalysts calcined at 800 o c and 1000 o c. 4.2 biodiesel yield analysis figure6showthe progress of the mustard oil transesterification reaction. the temperature was 60° c, the catalyst was 18 wt % hap, and the methanol/oil molar ratio was 20:1. the change of tg concentration with time was showing sigmoidal shape with three stages existed. in the initial stage of the reaction, production of fame was slow. then,the rate was rapid in the medium stage and finally in the last stage reached equilibrium in about 240 min. the increase in fame concentration was associated by an increase in glycerol concentration as it was liberated from tg molecules. however, the relative proportion of gl produced was not always the same as that of the esters produced. this is due to intermediate products such as dg and mg.this type of kinetics has already been observed for the homogeneously base-catalyzed transesterification [12–15]. this shape might be partially associated with the increasing solubility of methanol in the oil-fame phase with theformation of fame [16]. in all the experiments, the increase of the fame concentration followed the decrease of the tg al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 27 concentration. the concentrations of intermediate products, monoglycerides (mg) and diglycerides (dg), increased at the beginning of the reaction achieving their maximum, then decreased and finally stayed nearly constant. 4.3 mass transfer controlled region before checking the kinetic model, the intra particle diffusion and external liquid–solid mass transfer limitations bothwaschecked. the diffusion of the reactants from the surface to the active sites within the catalyst particles controls the reaction rate if the internal mass transfer limitations exist. firstly the effectiveness factor must be estimated, which can be estimated from the thiele modulus. the thiele modulus for a spherical particle is given as the following equation [17]: √ (7) where rp is the particle radius; k is the pseudo-first order reaction rate constant and deffis the effective diffusion coefficient. in the present work, the estimated values of the average particle size and the pseudo-first-order reaction rate constant for the catalyst amount of 18% were determined to be 2.8µ m and 0.060 min -1 , respectively. from the molecular diffusion coefficient and the porosity and the tortuosity of the catalyst particle , the effective diffusion coefficient can be determined. using the wilke and chang correlation [18] , the estimated values of the molecular diffusion coefficient of tg through methanol and tg were 6.2 x 10 -6 and 4.3 x 10-7 m 2 /s, respectively. thiele modulus value was calculated to be 0.01 or 0.038 for the diffusion of tg through methanol and tg, respectively. because of the small thiele modulus values (i.e. th< 0.4),that mean, the effectiveness factor is equal to 1and the internal diffusion resistance was negligible, and verifying the assumption (8). the reaction rate is controlled by the mass transfer of the reactant from the bulk liquid phase to the surface of the catalyst particles if external liquid-solid mass transfer limitations exist.by studying the effect of mixing speed on the reaction rate under the same reaction conditions, the presence of external mass transfer limitation wasconcluded experimentally. the reaction was carriedout at 600, 800 and 1000 rpm. the variation of tg conversion degree with timeis shown in fig. 7and indicates that both the reaction rate and the finalreactant conversion degree were not affected by the mixingspeed, signifying the absence of external mass transfer resistance. the phenomena that occurred in the initial region of the haptransesterification of mustard oil have been already observed in the reaction catalyzed by ca(oh)2[19]. in the beginning of the reaction, the methanol molecules occupied the catalyst surface active sites which reduced the available active specific catalyst surface area. as a result of that, the volumetric tg mass transfer coefficient was small (due to very small θ) and the overall reaction rate was limited by the tg mass transfer rate (the assumption 5). the methanol drops was break down and stabilized by surface active compounds formed in the reaction. the occurrence of the catalyst particle path through the surface of the dispersed methanol drops was increased due to the drop breakage process growth. the importance of the external mass transfer limitation was reduced to nothing with the progress of transesterification process as the available active specific catalyst surface and the tg mass transfer rate increased. 4.4 kinetics of reaction the boltzman function were used to define the sigmoidal fits of the experimental data on the methanol and fame concentrations in the liquid phase.the methanol concentration change with time on the al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 catalyst surface was calculated from the rates of fame and the methanol concentration changes dcb/dtanddcm/dt, respectively in the liquid phase. in fig.8the change of methanol concentration adsorbed on the catalyst surface active sites was plotted against the reaction time. it can be concluded that the hap catalyst was saturated with methanol at the initial period. the decrease in the concentration of the adsorbed methanol could be expected due to the addition of oil to the catalyst-methanol mixture. also due to glyceride mass transfer limitations, in the initial reaction period , the chemical reaction was very slow. after that, the adsorbed methanol concentration was decreased with reaction time and dq/dt< 0. because of the high adsorbed methanol concentration on the catalyst surface,the chemical reaction was faster than the methanol adsorption, but did not limit the overall process.the kinetic regime was changed based on the dq/dtchange in this period. the plot of dq/dt with time waschanged in three periods, firstly decreasing period, secondly reaching minimum period and then finally increasing period. a slow chemical reaction rate was concluded in the initial decreasing perioddue to the slower adsorptionof methanol molecules. in the second short period, the chemical reaction became faster due to the faster decreasing of methanol adsorption. it can be concluded that the kinetic regime start changing at the time when dq/dt reached the minimum in the plot. finally, whendq/dt> 0, it can be concluded that the methanol adsorption rate was faster than the chemical reaction. confirming the assumption (3), it was found that the mass transfer and the adsorption of methanol did not limit the transesterificationreaction at all. at the end of the reaction, mathematicallydq/dt = 0, i.e. q = const. in fig.9 the change of –ln (1xa)was plotted against time for the transesterification reaction carried out at different catalytic conditions. it can be seen from fig. 9 that the overall process was limited by tg mass transfer (kmt,a = const) and by chemical reaction, respectively. the increase of tg mass transfer due to the increase of the active catalyst surface in the presence of higher catalyst amounts was concluded. as an explanation, increasing the catalyst amount decrease the period where tg mass transfer limited the overall process rate.after a short period of time, the nonlinearity of –ln (1 xa)plotcan be seen due tothe increase in volumetric tg mass transfer coefficient with the increase of the available active catalyst surface. at the minimum dq/dt, the volumetric tg mass transfer coefficient became higher than the pseudo-first order reaction rate constant.thereforein the final reaction period, the reaction controlled the overall process rate. from the slope of relation –ln (1xa) with time in the final process period, the pseudofirst order reaction rate constant was calculated. it can be concluded that the lumped parameter ks,a.θo. am as well as the value of θo in the initial period of the transesterificationreaction were independent of the catalyst amount in the reaction system because the volumetric tg mass transfer coefficient increased proportionally with the catalyst amount as seen in fig. 10.practically, it was found that the pseudo-first order reaction rate constant did not depend on the catalyst amount with the value of 0.080 min -1 . when the tg mass transfer ratebecame equal tothe rate of the reaction, then at this time [10]: (8) where θl is the fraction of the available active specific surface when the chemical reaction began to control the overall process rate. now, by dividing eq. (8) by , we can obtain (9) al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 29 during the middle period of the transesterificationreaction and for a specified catalyst amount, the fraction of the available active specific surface was increased. although, the ratio θ1/θodecreased with increasing the catalyst mentioned amount (fig. 10). 4.5 modeling of reaction kinetics the decay of tg conversion degree in time was sigmoidally fitted. it was found that the relative deviations of calculated (based on the sigmoidal fit) and experimental tg conversion degree were ±10.3%, ±1.4%, ±1.8.0% and 2.1% at hap amounts of 2%, 8%, 12% and 18%, respectively.based on the proposed kinetic model, the tg conversion degree was calculated from the following equations[19]:  for tg mass transfer controlled regime (kmt,a = const): ( ) (10)  for chemical reaction controlled regime: ( ) (11) the kinetic model was also compared with the experimentbased on the changes of the molar concentrations of tg andfame. figure11 shows that the kinetic model was fitted well with the experimental data in the initial and later reaction periods but not in the period when fame formation rate rapidly increased. 5. conclusions 1. compared to catalysts calcined at other temperatures, the bone catalysts calcined at 900 o c shows low crystallite size and higher bet surface area . 2. the optimum conditions for maximum biodiesel yield were(20:1 molar ratio of methanol to oil,addition of 18 wt% of bone catalyst (calcined at 900 o c, 2 hr), 60 o c reaction temperatureand reaction time of 4 hrs). 3. a simple model was used to study the kinetics of hap heterogeneously catalyzed transesterificationreaction. 4. the activity of hap catalyst effect thetransesterification reaction between methanol and glyceride molecules which adsorbed on the surface catalyst active sites. 5. the sigmoidal kinetics of the process was explained by tg mass transfer limitations in the initial region, followed by the chemical reaction controlled region in the latter period. the overall chemical reaction followed the pseudo-first order reaction kinetics. 6. the tg mass transfer limitation was caused by the low available active specific catalyst surface because of the high adsorbed methanol concentration. 7. the available active specific catalyst surface increased with the catalyst amount increase, thus the mass transfer resistance significantly decreased at higher catalyst amounts. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 30 references [1] enweremadu cc, mbarawa mm. technical aspects of production and analysis of biodiesel from used cooking oil – a review. renewable and sustainable energy reviews 2009;13:2205–24. [2] borges m.e., díaz l. recent developments on heterogeneous catalysts for biodiesel production by oil esterification and transesterification reactions: a review. renewable and sustainable energy reviews 2012; 16: 2839– 2849. [3] dossin, t.f., reyniers, m.-f., marin, g.b. kinetics of heterogeneously mgocatalyzed transesterification. appl. catal. b 2006; 61, 35–45. [4] wang, l., yang, j.. transesterification of soybean oil with nano-mgo or not in supercritical and subcritical methanol. fuel 2007; 86l: 328–333. [5] singh, a.k., fernando, s.d.. reaction kinetics of soybean oil transesterification using heterogeneous metal oxide catalysts. chem. eng.technol. 2007; 30: 1716–1720. [6] kouzu, m., kasuno, t., tajika, m., sugimoto, y., yamanaka, s., hidaka, j. calcium oxide as a solid base catalyst for transesterification of soybean oil and its application to biodiesel production. fuel 2008; 87: 2798–2806. [7] jazie, a. a., pramanik, h., & sinha, a. s. k. transesterification of peanut and rapeseed oils using waste of animal bone as cost effective catalyst. materials for renewable and sustainable energy2013; 2(2): 1-10. [8] giuliano f zagonel, patricio peralta-zamora, luiz p ramos. multivariate monitoring of soybean oil ethanolysis by ftir. talanta 2004;63:1021–1025. [9] aocs. official and tentative methods. chicago: american oil chemists society; 1980. [10] smith, j.m. chemical engineering kinetics. 3rd edition, mcgraw-hill international book company, 1981. [11] wang l, yang j. transesterification of soybean oil with nano-mgo or not in supercritical and subcritical methanol. fuel 2007; 86:328–33. [12] jazie, a. a., sinha, a. s. k., &pramanik, h. optimization of biodiesel production from peanut and rapeseed oils using response surface methodology. international journal of biomass & renewables, 2012; 1(2): 9-18. [13] noureddini h, zhu d. kinetics of transesterification of soybean oil. j am oil chemsoc 1997;74:1457–63. [14] stamenkovic´ os, todorovic´ zb, lazic´ ml, veljkovic´ vb, skala du. kinetics of sunflower oil methanolysis at low temperatures. biorestechnol 2008;99:1131–40. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 31 [15] vicente g, martinez m, aracil j, esteban a. kinetics of sunflower oil methanolysis. indengchem res 2005;44:5447–54. [16] stamenkovic´ os, lazic´ ml, todorovic´ zb, veljkovic´ vb, skala du. the effect of agitation intensity on alkali-catalyzed methanolysis of sunflower oil. biorestechnol 2007;98:2688–99. [17] levenspiel o. chemical reaction engineering. 3rd ed. new york: john wiley and sons; 1999. [18] poling, b.e., prausnitz, j.m., o’connell, j.p. the properties of gases and liquids, fifth ed. mcgraw-hill, new york;2004. [19] stamenkovic´ olivera s., veljkovic´ vlada b., todorovic´ zoran b., lazic´miodrag l., bankovic´ -ilic´ ivana b., skaladejan u. modeling the kinetics of calcium hydroxide catalyzed methanolysis of sunflower oil bioresource technology 2010;101: 4423–4430 table 1: the properties of mustard oil. acid value (mg koh/g) 0.23 saponification value (mg koh/g) 175 iodine value (g j2/100 g) 112 density (kg/m 3 ) at 20 o c 910 viscosity (mpa s) at 20 o c 88 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 32 figure 1: photograph of experimental setup. figure 2: ftir spectra of biodiesel product. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 33 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 34 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 0 600 1200 900 o c 800 o c in te n si ty ( a .u .) 2 theta 1000 o c b on e 9 00 i i b on e 9 00 i * * b on e 9 00 * * b on e 3 00 120 100 80 60 40 20 0 20 40 60 80 % t 500 100 0 150 0 200 0 250 0 300 0 350 0 400 0 w av enu mber s ( c m1) figure 4: xrd of the calcined bone catalyst at 800 ˚c, 900 ˚c and 1000 ˚c, respectively. ■ cao ▲ ca(oh)2 □ hap ● caco3 ■ ■ ▲ ▲ □ □ □ □ □ □ □ ● □ □ □ □ uncalcined 1000 o c 900 o c 800 o c v2 co3, 850 cm -1 po4 -3 , 1035 cm -1 po4 -3 , 603cm -1 v3co3, 1412 cm -1 oh -1 , 3573 cm -1 figure 5: ftir spectra of fresh bone and calcined bone samples at 800 o c, 900 o c and 1000 o c , respectively . al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 35 0 50 100 150 200 250 300 0 20 40 60 80 100 f a m e , t g , m g , d g ( % ) time (min) fame (%) tg (%) mg (%) dg (%) 0 50 100 150 200 250 300 0.0 0.2 0.4 0.6 0.8 1.0 600 rpm 800 rpm 1000 rpm x a (1 ) time (min) figure 6: the variations of the reaction mixture composition with the progress of hapcatalyzed transesterification of mustard oil (catalyst amount, based on the oil weight, %: 18; average catalyst particle size, µm: 2.8. figure 7: the influence of the agitation speed on the conversion degree of tg (60 o c;methanol to oil ratio: 20:1; 18% of the catalyst based on the oil amount. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 36 0 50 100 150 200 250 300 350 -2.2 -2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 d q /d t (m o l/ (g .m in )) time (min) 2 wt% 8 wt% 12 wt% 18 wt% 0 50 100 150 200 250 -1 0 1 2 3 4 5 6 7 8 9 10 11 -l n (1 -x a ) time (min) 2 wt% 8 wt% 12 wt% 18 wt% figure 8: the rate of the adsorbed methanol concentration variations on the catalyst active sites with the progress of hap-catalyzedtransesterification (catalyst amount, based on the oil weight,%; average catalyst particle size, µm: 2.8). figure 9: dependence -ln(1 -xa) versus tduring hap-catalyzedtransesterification (catalyst amount, based on the oil weight,%; average catalyst particle size, µm: 2.8). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 37 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 0.0005 0.0010 0.0015 0.0020 0.0025 0.0030 0.0035 hap catalyst amount (%) v o lu m e tr ic t g m a s s t ra n s fe r c o e ff ic ie n t (m in -1 ) 0 20 40 60 80 100 120 t h /t h o (1 ) 0 50 100 150 200 250 300 0.0 0.5 1.0 1.5 2.0 2.5 2 fame (%) 8 fame (%) 12 fame (%) 18 fame (%) 2 tg (%) 8 tg (%) 12 tg (%) 18 tg (%) time (min) t g c o n c e n tr a ti o n ( m o l/ d m 3 ) 0.0 0.5 1.0 1.5 2.0 2.5 f a m e c o n c e n tr a ti o n ( m o l/ d m 3 ) figure 10: the volumetric tg mass transfer coefficient and the ratio θ1/ θ2at various catalyst amounts (average catalyst particle size, µm: 2.8). figure 11: the comparison of tg and fame concentrations calculated by the kineticmodel (mass transfer, chemical reaction) with the experimental data during hapcatalyzedtransesterification (catalyst amount, based on the oil weight,%; average catalyst particle size, µm: 2.8). effect of bed roughness distribution and channel slope on rectangular free overfall al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 115 effect of bed roughness distribution and channel slope on rectangular free overfall ahmed y. mohammed univ. of mosul, coll. of eng., dept. of dam & water resources, eng. p.o.box 11244, mosul, iraq; ahmedymaltaee@gmail.com abstract in this paper, the free overfall in rectangular channel with a different slopes and bed rough distribution was studied. bed roughness was made of wood allocated in three different cases: two, three and zigzag rows. the aim of this study is to obtain discharge equations for free overfall depending on brink depth and slope. three empirical equations proposed for calculating discharge. these equations influenced by slope, channel bed roughness as well as method of roughness distribution. three rows bed roughness having grater effect on these relationships at steeper slopes. the average values of hc/he at smooth bed is greater by (4%) with respect to that for bed rough at two rows, by (19%) with respect to that for bed rough at zigzag rows and by (24%) with respect to that for bed rough at three rows, so that values for three rows rough and horizontal channel is greater by (4%) with respect to that for channel slope at (1/200) and by (14%) with respect to that for channel slope at (1/100). keywords: overfall, brink depth, bed roughness, bed slope تاثير توزيع خشونة القعر وميل القناة على المسقط المائي مستطيل المقطع احمد يونس محمد جامعة الموصل/ كلية الهندسة/ قسم هندسة السدود والموارد المائية :الخالصة يث مثلت مادة في هذا البحث دراسة المسقط المائي مستطيل الحافة تحت ظروف تخشين مختلفة لمادة القعر وبميول مختلفة, حتم صفوف وبثالث صفوف متخالفة )زكزاك(. هدف الدراسة هو تخشين القعر بالخشب ووضعت بثالث طرق مختلفة: بصفين وثالث معادالت وضعية اليجاد ثالثاليجاد معادالت التصريف للمسقط المائي باالعتماد على عمق الماء عند الحافة والميل. استنبطت تمد على الميل وخشونة القعر باالضافة الى طريقة توزيع التخشين. واوضحت البيانات بان التخشين بثالث التصريف وهذه المعادالت تع اكبر على النتائج.صفوف وميل حاد ذو تاثير %( مقارنة بقيمها عند القعر المخشن بصفين من الخشب و اكبر 4( عند القعر االملس هي اكبر بحدود )hc/heان معدل القيم لعالقة ) %( مقارنة بقيمها عند القعر 44%( مقارنة بقيمها عند القعر المخشن بثالث سوف مخالف )زكزاك( بينما هي اكبر بحدود )91حدود )ب ( 1/200%( مقارنة بميل القناة )4, كما ان هذه القيم للمسقط المخشن بثالث سوف وميل افقي هي اكبر بحدود )المخشن بثالث سوف (1/100بميل القناة )%( مقارنة 94واكبر بحدود ) mailto:ahmedymaltaee@gmail.com al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 116 list of notation: 1. introduction: the study of free overfall is important because of possible usage of it as a discharge measuring devise (tigrek et.al.,2008).many investigators have studied the end depth discharge relationship in different channels cross section. bauer s.and graf w.(1971) submitted experimental study for free overfall with different channel slopes and obtained relationships between critical depth hc and brink depth he ,this relationship using to find discharge equations and the results compared with data from previous investigators. ferro v.(1992) presents experimental study of a free overfall in a rectangular channel, having different values of channel width ,the relationship between end depth he and critical depth hc had to be established as he=0.76 hc , this relationship was used to obtain discharge equation .dey s.(1998) presents an analytical model for a free overfall from smooth circular channels applying a momentum approach based on the boussinesq assumption. the end depths in subcritical and supercritical discharges were estimated. the relation of brink depth he to critical depth hc is found to be around 0.75.dey s.(2001) studied a simplified approach for the computation of end depth of a free overfall in horizontal or mildly slopping inverted semicircular channels. the free overfall is simulated by that over a sharp crested weir to calculate the end depth ratio. the mathematical model is calibrated by the experimental data.the end depth relationship related to the critical depth is around 0.705.ramamurthy et.al.(2004) studied free overfall to determine vertical distribution of the velocity components and static presume heal at different points across the end section of a horizontal trapezoidal channel using momentum equation. using this method improves the accuracy of predicting discharge q from measurements of brink depth he. pal m. and goel a.(2006) presented an application of a support vector machine based modeling technique to determine the end depth ratio and discharge of free overfall occurring over an inverted smooth semi-circular channel and a circular channel with flat base , using data collected from other studied. the value of end depth raio is to be 0.704. cd coefficient of discharge fr froude number g gravitational acceleration (lt -2 ) hc critical depth (l) he brink depth (l) ho normal depth (l) hw head over sharp crested weir (l) k roughness height (l) n coefficient of manning q discharge (l 3 t -1 ) qact actual discharge (l 3 t -1 ) so channel bed slope ρ density of water (ml -3 ) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 117 ahmed y.m. (2008) presented an experimental study and analysis for effect of channel slope on straight vertical and skew free overfall for a rectangular channel with different slopes, and find the discharge over skewed model is greater by (21%) from straight vertical. ahmed y.m. (2009) studied the behavior of free surface flow on a rectangular free overfall which has a triangular shape, the results prevail that the ratio of brink depth to critical depth at center line for falls inclined with flow direction was greater by (3%) than that falls on the opposite direction, this value increased to (27%) when froud number increased. the purpose of this study is to experimentally investigate, the effect of bed roughness distribution and channel bed slope on the brink depth at horizontal bed slope, 1/100 and 1/200 slopes .the results obtained are presented to fined discharge equations for free overfall depending on brink depth as well as slope. this will be achieved practically using free overfall to calculate discharge in smooth and rough bed. 2. experimental setup: experiments were setup in the hydraulic laboratory of the water resources department, university of mosul, iraq. at a rectangular flume with glass sides was 0.3m wide 0.45m deep and 10m long shown in fig.(1). the flume was set to three slopes (0, 0.005 (1/200) and 0.01(1/100)), the discharge was conducted using a rectangular sharp crested weir installed upstream of the channel, with dimensions (30×30×1) cm. the upstream normal depths of approximately 4, 5.5, 6.5, 7.5 and 9.5 cm were produced in a flume. the free overfall was 0.3m wide 0.15m height and 1m long. roughness was made using cylindrical wood 1cm diameter and 1cm height, allocated in three different cases: two rows; 20cm distance between them, three rows; 10cm distance between them and three rows zigzag; 10cm distance between them, shown in fig.(2). the water surface profile (w.s.p.) was measured using a point gage over and between roughness rows, head over brink he, normal depth over free overfall ho and head over sharp crested weir upsteam hw were measured ,so actual discharge qact can be calculated from the following equation: qact=0.714 hw 1.5 (1) where qact in (l/s) and hw in (cm) this equation was found from volumetric calibration by measuring hw and volume of water with respect to time, the data shown in table 1. 3. experimental program: in each experiment slope, normal depth, brink depth, water surface profile and discharge were measured. the total number of experiments conducted was 60. there were 15 experiments run for smooth bed and 45 experiments run for rough bed with three al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 118 different slopes (0, 0.005 and 0.01) as well as three types of roughness distribution (two, three and zigzag rows). 4. results and discussion: 4.1. relation between he and hc: the relation between brink depth he and critical depth hc for the three different slopes and the three types of roughness distribution were plotted and studied. the magnitude of ratio he/hc seems to be dependent of both slope and channel bottom roughness .at the same value of hc ,the greatest value of he happened when bed is smooth and horizontal channel while the lowest values of he observed when bed is roughed at three rows and (1/100) channel slope. fig.(3) shows the effect of three types of roughness distribution in channel slope (1/100) .as depicted in this figure ,the magnitude of he increases when discharge value increasing and this value for smooth bed are grater by (4%) with respect to that two rows roughness, by (9%) with respect to that zigzag roughness and by (14%) with respect to that three rows roughness because of roughness distribution effects. fig.(4) shows the effect of the three channel slope at three rows roughness bed .as depicted in this figure the magnitude of he for horizontal channel is greater by (7%) with respect to that (1/200) channel slope and by (10%) with respect to that (1/100) channel slope for the same value of hc (tegrike et.al.,2008). the brink depth he at sloping rough free overfall in a rectangular channel is depending on critical depth hc ,channel slope so roughness hight k as folloing: he=f(hc , so ,k) (2) dimensional analysis for the given parameters gives: (3) it was found that a good relationship was obtained when he/hc was a relation with so and e h k .the following equations were obtained using the statistical package for the social sciences (spss, version 17). the equation for two rows roughness distribution with r 2 =0.985 is: e o c e h k s h h /18.0628.0  (4) the equation for zigzag roughness distribution r 2 =0.975 is: ),( e o c e h k sf h h  al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 119 e o c e h k s h h /168.058.0  (5) the equation for three rows roughness distribution r 2 =0.988 is: e o c e h k s h h /16.056.0  (6) 4.2. predicting discharge: the critical depth hc for a rectangular channel is a simple relationship between acceleration and uniform discharge per unit width q as following: 3 2 g q h c  (7) where g is acceleration due to gravity. thus if hc could be measured, then discharge in channel could be calculated. the equations (4, 5 and 6) now be used to predicting discharge using equation (7). so, discharge equation for two rows roughness distribution is: 2 3 2 3 )185.0628.0( 94.0 eo e hs h q   (8) and discharge equation for zigzag roughness distribution is: 2 3 2 3 )168.058.0( 94.0 eo e hs h q   (9) discharge equation for three rows roughness distribution is: 2 3 2 3 )16.056.0( 94.0 eo e hs h q   (10) fig. (5) shows the compared of discharge computed from eqs. (8-10) to experimental values as well as that values computed by davis et. al. (1998), and tigrek et. al. (2008). as al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 120 depicted in this figure the overall correlation is 0.97 thus we can used eqs. (8-10) as discharge calculation when known the slope and the roughness distribution. 5. conclusions: in this study the effect of bed roughness distribution and channel bed slope were studied in a rectangular free overfall, the relation between critical and brink depth eqs. (4-6) as well as predicted discharge eqs. (8-10) were observed in all cases of bed rough and channel slopes. the average values of hc/he at smooth bed is greater by (4%) with respect to that for bed rough at two rows, by (19%) with respect to that for bed rough at zigzag rows and by (24%) with respect to that for bed rough at three rows, so that values for three rows rough and horizontal channel is greater by (4%) with respect to that for channel slope at (1/200) and by (14%) with respect to that for channel slope at (1/100), so the discharge predicted shown that the greatest values happened when bed rough at three rows. these equation can used practically to calculate discharge in smooth and rough bed. references: 1. ahmed y.mohammed (2008). "effecting of channel slope on flow characteristics for straight vertical and skew free overfal", alrafidain eng. journal, 17(1), 80-90. 2. ahmed y.mohammed (2009). "hydraulic characteristics of free overfall with triangular end lip", 33rd iahr congress: water eng. for a sust. env., 11881199. 3. bauer s.w.and graf w.h.(1971). "free overfall as flow measuring device", journal of irrigation and drainage engineering, asce, 97(1),73-83. 4. davis a.c.,brain g.s. and jacob r.p.,(1998), " flow measurement in sloping channels with rectangular free overfall ." journal of hydraulic engineering, asce, 124(7), 760-763. 5. dey s., (1998), " end depth in circular channels", journal of hydraulic engineering, asce, 124(8),856-863. 6. dey s., (2001), "flow measurement by end-depth method in inverted semicircular channels."flow measurement and instrumentation, 12(4), 253-258. 7. ferro v., (1992), " flow measurement with rectangular free overfall ", journal of irrigation and drainage engineering, asce, 118(6),650-657. 8. pal m. and goel a.,(2006)," prediction of the end-depth ratio and discharge in semi-circular and circular sloped channels using supported vector machine. "flow measurement and instrumentation, 17(3), 49-57. 9. ramamurthy a.s., zhai c. and junying q, (2004), " end depth discharges relation at free overfall of trapezoidal channels", journal of irrigation and drainage engineering, asce, 130(5),432-436. 10. tigrek s., firat c.e. and ger a.m, (2008) ," use of brink depth in discharge measurement" journal of irrigation and drainage engineerge, asce, 134(1),89-95. al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 121 table (1): discharge volumetric calculation q(l/s) time(s) volume(l) h(cm) 2.886 7 20.2 2.5 3.673 5.5 20.2 3 6.733 3 20.2 4.5 9.182 2.2 20.2 5.5 11.882 1.7 20.2 6.5 14.429 1.4 20.2 7.5 16.833 1.2 20.2 8.5 18.364 1.1 20.2 9 (a) (b) (c) fig. (2) models of roughness distribution; (a) zigzag, (b) three rows, (c) two rows 10cm 20cm 10cm 100cm 10cm 20cm 3 0 c m flow direction ho he figure (1): channel sketch b=0.3m top view tank 3 tank 2 tank 1 01m 1.4m side view 0.45m pump channel basin tank 1 tank 2 tank 3 free overfall weir al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 122 mode smooth slope 1/100 slope 1/200 horizontal tow rows three rows slope 1/100 slope 1/200 horizontal slope 1/100 slope 1/200 horizontal slope 1/100 slope 1/200 horizontal wood 1cm three row zigzag chart (1): experimental program 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 3 4 5 6 7 8 9 hc (cm) h e ( c m ) smooth tw o row s three row s zigzag smooth tw o row s zigzag three row s figure (3) effect three types of roughness distribution in channel bed slope (1/100) al-qadisiya journal for engineering sciences ,vol. 6.no 2 year 2013 123 1 1.5 2 2.5 3 3.5 4 4.5 5 3 4 5 6 7 8 9 hc (cm) h e ( c m ) horizontal slope 1/100 slope 1/200 horizontal slope 1/200 slope 1/100 figure (4) effect of three channel slope at three rows roughness bed 0 5 10 15 20 25 30 0 5 10 15 20 25 30 qthe(l/s) q a c t( l/ s ) present w ork davis et. al. (1998) tigrek et. al.(2008) figure (5) comparison of actual and theoretical discharge al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 horizontal shear transfer between concrete and bricks received 14 september 2015 accepted 9 november 2015 abstract horizontal shear transfers through interfaces between two materials need to be studied accurately especially when the interface separates two different materials. in this study the two materials are concrete and bricks. this interaction can be formed in the regions where concrete is rested on brick walls in so many positions in construction. the study focuses on an experimental work through a series of push-off tests for ( concrete to bricks, cement mortar to bricks ) taking into consideration that the shear connectors are steel bars. throughout push–off tests and due to the applied horizontal forces as slip had been attained. this forces and slips are recorded and graphically drawn. a statistical regression was made to find the most representative formula of the mechanism of shear transfer between concrete with bricks and between cement mortar with bricks. the predominant factor in shear transfer between concrete and bricks is the amount of shear connectors because as number of dowel bars increases the shear strength increases. the value of force recorded at 2mm slip for concrete to concrete was around three to four times that for concrete to bricks in existence of steel bars or steel dowels. this means that concrete to bricks is weaker than that between two concretes. key words: aggregate interlock, cement mortar, dowels, shear transfer. introduction in so many contact regions of structural members (during construction) shear is transferred horizontally due to a limited movement of one part against other. these regions may be concrete to concrete or concrete to other materials. concrete to concrete had been studied by so many researchers (zheng l.x.&burgoyne c.j., husain m.h. et al,yashiki tanaka et al and k.f. et al) and yet the work still not finishes. transferring horizontal shear is very complicated problem because of the effect of many variables like applied normal load, shape of the finish of contact area (smooth or rough), type of the materials forming contact area and the mechanism used to clamp the two parts through interface area. dhurgham abdul jaleel resool civil technical department, najaf technical institute, al-furat al-awsat technical university, iraq assistant lecturer email: dergamalhamdany@yahoo.com dr. hakim s. m. al-kurayshi civil technical department, najaf technical institute, al-furat al-awsat technical university, iraq assistant professor email: ntit.10006@gmail.com mailto:dergamalhamdany@yahoo.com mailto:ntit.10006@gmail al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 an extensive statistical analysis of 88 push-off specimens were performed by walraven et al (1978) to find the horizontal shear strength between two faces of concrete. this analysis yielded the following equation: psi (1) where =horizontal shearing stress. =clamping stress. banta e.t. (2005) studied the media between the bridge decks to the top flange of the beams. twenty-four push-off tests were performed to determine shear transfer design equations for shear strength of composite ductal (r) and lightweight concrete sections. the results of his work were all found to be conservative but it was recommended that the equation from aashto-lrfd specifications (2004) be used for design. the horizontal shear strength that was used by pci on the work of shaikh a.f. (1978). the simplified from of this equation is shown below: √ (2) where ø=0.85 for shear. =1.0 for normal weight concrete. =0.85 for sand-lightweight concrete. =0.75 for all-lightweight concrete. the work of mattock et al (1975) proposed the following linear equation to determine the horizontal shear strength of an initially cracked interface: psi (3) where: psi in concrete two mechanisms play as an active role in shear transformation namely aggregate interlock and dowel action. when the materials of the contact surfaces are changed these mechanisms need to be studied. in this work concrete was taken to be the first material whereas the second material was bricks. connection between concrete and bricks can be fulfilled through interlock between concrete aggregates and brick material besides the concrete studs formed as a result of filling the brick holes by concrete. the present paper focused on this mechanism and another clamping mechanism using steel bars buried in brick holes and extended to the concrete layer as shear connectors. concrete to bricks can be seen in construction of brick walls constructed on concrete lintels , concrete beams rested directly on bearing walls or on partitions, concrete decks on brick walks and so on. the normal loads applied through concrete members try to push members under them. if the members beneath concrete are brick walls, so this normal load will create horizontal force (due to friction) making slip in the two members and forming an interface area. the present study focuses on this interaction without assuming an old crack or interface. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 experimental work it was decided to achieve this work for the aim of finding out what will occur in the media between concrete and bricks interface. practical work was including items of preparing molds, equipment's, materials and testing devices. a summary here can be given for the practical work of these items. seventy tests were decided to be done. the first ten tests were for concrete poured on an old concrete without changing the surface shape between them. the second ten tests were for a concrete rested on bricks through two ø12 mm dowels. in the third ten tests same procedure was consumed but with four dowel bars while fourth ten tests was done using six dowel bars. the remainders were thirty tests done on cement mortar and bricks because bearing walls are constructed through so many rows of bricks connected to upper and lower rows by cement mortar (cement paste). these thirty tests were divided also to three groups each group includes ten tests started by mortar and bricks with two dowel bars, four dowel bars and six dowel bars respectively. table (1) shows the details of these tests. materials used the materials used in this work include cement, gravel, sand and bricks. the cement used is iraqi cement locally manufactured and it was coincided with iraqi specifications (iqs, no.5, 1984) as in table (2). this specification is also coincided with portland cement properties. primary setting time of the cement used was (65 min.) and final setting time was (460 min.). the coarse aggregate used was rounded gravel of max. size (19 mm) and it was found that it was coincided with iraqi specifications (iqs, no.45, 1980) as in table (3). the fine materials were sand taken from najaf quarries and whole of the tests were done which were gave results coincided with iraqi specifications (iqs, no.45, 1980) as in table (4), zone no. 2. the samples of bricks used were of class b manufactured in iraqi factories in which their dimensions are 240x115x75 mm. the bricks are perforated by so many holes to achieve strong connection with mortar. the ratio of perforations was not more than 25% of the total size of brick. all of the tests include water absorption, density, fluorescent test and bearing in compression had been done. the steel bars used as dowels are of ø13 mm bars and they were coincided with american specifications astm a615/ a615m-01b, as shown in table (5). mold, equipment and devices used wooden molds were used to achieve the preparation of samples of push-off tests. the dimensions of each mold are illustrated in fig. 1.the mold contains two parts the outside one called (a) which is a container prism of 41x24x12.5cm in dimensions whereas the internal part (b) manufactured from wood was used as a separator between the two materials during casting. this wood separator divide the mold into two pieces, piece one may be brick or it may be concrete while piece two was always from concrete as shown in fig.2. the two pieces were erected in a manner as shown in the photos (1, 2, 3). a load cell and dial gage were used and assembled to measure the load applied and slip due to horizontal movement. ten samples of ordinary concrete (piece a) were casted and cured in water baths for 28 days. the average compressive strength of the cubes governed was 30.8 mpa. the ten upper pieces of concrete (piece b) were casted over lower pieces without connectors. the upper piece was reinforced by two bars of ø10mm in the upper layer and 2 ø8mm in the lower layer. the reinforcement of this assemblage (upper part b) can be shown in fig. 3. . this procedure was used for the next ten samples with first piece of brick clamped to upper piece by two steel dowel bars ø12mm inserted al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 in brick holes and fixed in their holes positions by the material of the upper part. the steps of the previous procedure were repeated for whole samples except the number of dowels was changed to four and six bars respectively. another try was done to see the effect of the mortar because there are so many members constructed from cement mortar rested on bricks. the upper piece was prepared as mortar material from cement and sand by a ratio of (1:3) as used in construction of bearing walls. the average compressive strength of 5x5x5 cm molds was 21 mpa. same procedure was done in push-off tests and all of the results of applied loads and slip were recorded. results and discussion the results of the push-off tests were tabulated in table (6) where the applied normal load is 1 kn. each number of these results represents an average of ten readings. seven cases were taken into consideration as previously mentioned. against each slip measured the value of horizontal force applied was recorded. figure (4) shows the results tabulated before in graphical form. it is clearly evident that concrete to concrete failed at values of shear force higher than concrete to bricks. this leads to the truth that concrete to concrete has more strength against shear and that is due to the interlock of aggregate and high coefficient of friction. the value of force recorded at 2mm slip for concrete to concrete was about three to four times that for concrete to bricks in existence of steel bars or steel dowels from the same figure it can be seen that the results of the shear transfer between mortar and bricks are very low and they are approximately coincided. this is due to the weakness of the bricks materials as a major reason and low coefficient of friction between the skin of bricks and cement mortar. concrete to bricks with two dowels samples were failed at very small slip (2mm) while that cases (with four or six dowels) were failed at values of 8.5mm. figures (5, 6, and 7) show that as number of dowels exceeds two bars the value of maximum shear strength increases. so the predominant factor here in shear transfer is the amount of shear connectors. for two dowels the maximum value of shear force was 14 kn while increasing two bars more, the force jumped to 20.4 kn and it was jumped to 32.1 kn for six dowel bars. a statistical regression was made to find the most representative formula of the mechanism of shear transfer between concrete and bricks. the governed formula was as follows: (4) where =shear force transferred in kn. =slip in mm. the results of shear transfer between cement mortar and bricks can be seen in figures (8,9,10). these three figures show that if the numbers of dowels are two or four and even if it is six, there is no any improvement in shear force. shear force for the three cases was not more than 4.5 kn. so it is advised not to use dowel bars between cement mortar and bricks. the governed formula covering the behavior of the shear transfer between cement mortar and bricks was as follows: which is the same as previous formula used for concrete rested on bricks. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 conclusions and recommendations the following conclusions can be drawn in the present study: 1. it is advised to use shear connectors as dowel bars between concrete and bricks to prevent and minimize the harmful slip between the two adjacent surfaces. 2. the value of force recorded at 2mm slip for concrete to concrete was around three to four times that for concrete to bricks in existence of steel bars or steel dowels. this means that concrete to bricks is weaker than that between two concretes. the values of forces corresponding to 2 mm can be seen in table (6). 3. the predominant factor in shear transfer between concrete and bricks is the amount of shear connectors because as number of dowel bars increases the shear strength force increases. the ratio of the increase of shear force corresponding to slip recorded can be determined from eq. (9). 4. the results of the shear transfer between mortar and bricks are very low and they are approximately coincided. so it is advised not to use dowel bars between cement mortar and bricks. the ratio of the increase of shear force corresponding to slip recorded can be determined from eq. (5). 5. the work needs testing prototypes to see the truth as it and build the most correct opinions about the real behavior between concrete and bricks. references: [1] banta e. ''horizontal shear transfer between ultrahigh performance concrete and lightweight concrete'', msc thesis, department of civil and environmental engineering, the virginia polytechnic institute, blacksburg, virginia, feb.2005. [2] husain m., nazar k., hakim s. ''dowel action between two concretes'', journal of engineering, university of technology, baghdad, 2009; vol.15, no.2 [3] mattock a., johal l., chow h. ''shear transfer in lightweight reinforced concrete'', pci journal 1975; vol.22, no.1, pp 20-39. [4] sarsam k., ridha m., mahdi z. ''investigation of the dowel and friction forces in fiber reinforced ultrahigh performance concrete beams'', engineering and technology journal, university of technology, baghdad, 2012; vol.30, no.16. [5] shaikh a.f. ''proposed revisions to shear-friction provisions'', pci journal 1978; vol.23, no.2, pp 12-21. [6] wallraven j., frenay j., pruijssers a. ''influence of concrete strength and load history on the shear friction capacity of concrete members''. pci journal 1987; vol.32, no.1, pp 66-84. [7] yoshika t., jun m., hiroshi y., hiroshi a., saddaki n. ''effectiveness of cohesion on horizontal shear transfer for composite prestressed concrete girders'' , cooperative research on connections of precast prestressed concrete elements for bridges by pwri and the japan prestressed concrete contractors association (jpca) in fy 2005-2006. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 table (1): details of the tests done. materials used number of tests number of dowels tests done concrete to concrete 10 --push-off, compressive strength of concrete. concrete to bricks 10 2 push-off, compressive strength of concrete, compressive strength of bricks. concrete to bricks 10 4 push-off, compressive strength of concrete, compressive strength of bricks. concrete to bricks 10 6 push-off, compressive strength of concrete, compressive strength of bricks. mortar to bricks 10 2 push-off, compressive strength of cement mortar, compressive strength of bricks. mortar to bricks 10 4 push-off, compressive strength of cement mortar, compressive strength of bricks mortar to bricks 10 6 push-off, compressive strength of cement mortar, compressive strength of bricks table (2): results of used cement. test ordinary portland cement fineness (m2/kg) 230 sitting initial (min.) 45 final (hr.) 10 stability (%) 0.8 compressive strength mpa 3 day 15 7 day 23 table (3): grain size distribution of coarse gravel. sieve opening (mm) percentage passing 37.5 100 20 95-100 10 30-60 5 0-10 table (4): grain size distribution of fine gravel. sieve opening (mm) percentage passing 10 100 4.75 95-100 2.36 75-100 100 55-95 0.600 35-59 0.300 8-30 0.15 0-10 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 table (5): specification of steel bar used. standard requirement specification nominal mass (kg/m) 0.994 diameter (mm) 12.7 cross section area (mm 2 ) 129 parameter (mm) 39.9 deformation height (mm) 0.51 deformation spacing (mm) 8.9 tensile strength (mpa) 620 yield strength (mpa) 420 elongation per 200 mm length at least (mm) 9 table (6): results of push-off tests. mortar to bricks using steel bars as shear connectors of: concrete to bricks using steel bars as shear connectors of: concrete to concrete horizontal displacement (mm) 6ø12mm 4ø12mm 2ø12mm 6ø12mm 4ø12mm 2ø12mm no. reinf. force kn force kn force kn force kn force kn force kn force kn 0 0 0 0 0 0 0 0 0.6 0.6 0.4 2.3 2.0 1.0 14.0 0.5 1.4 1.4 1.3 7.6 7.6 1.2 23.6 1 2.3 2.0 2.1 16.2 14.0 3.4 35.3 1.5 3.7 3.5 3.3 18.3 14.0 14.0 56.7 2.0 4.1 3.8 3.6 24.7 14.0 110.6 2.5 4.4 4.3 3.8 32.1 16.2 3.0 4.5 4.5 4.0 25.1 16.2 3.5 18.3 16.2 4.0 18.3 16.2 4.5 22.6 16.2 5.0 22.6 16.2 5.5 20.4 18.3 6.0 20.4 18.3 6.5 18.3 18.3 7.0 16.2 18.3 7.5 14.0 20.4 8.0 14.0 20.4 8.5 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 figure (1): shape and dimensions of the wooden molds used. figure (2): lay out of the materials in the mold. figure (3): reinforcement of the concrete part b. . al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 figure (4): results of push-off tests figure (5): concrete rested on bricks with two dowel bars. 0.00 2.00 4.00 6.00 8.00 10.00 0.00 40.00 80.00 120.00 types of materials studied concrete to concrete concrete to bricks with two dowels concrete to bricks with four dowels concrete to bricks with six dowels mortar to bricks with two dowels mortar to bricks with four dowels mortar to bricks with six dowels s h e a r f o rc e a p p li e d i n ( k n ) slip in (mm) al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 12 figure (6): concrete rested on bricks with four dowel bars. figure (7): concrete rested on bricks with six dowel bars. shear force against slip for concrete to bricks w ith tw o dow els 0 5 10 15 0 2 4 6 8 10 slip in (m m ) s h e a r fo rc e i n ( k n ) shear force against slip for concrete to bricks w ith tw o dow els 0 5 10 15 0 2 4 6 8 10 slip in (m m ) s h e a r fo rc e i n ( k n ) shear force against slip for concrete to bricks w ith tw o dow els 0 5 10 15 0 2 4 6 8 10 slip in (m m ) s h e a r fo rc e i n ( k n ) shear force against slip for concrete to bricks w ith tw o dow els 0 5 10 15 0 2 4 6 8 10 slip in (m m ) s h e a r fo rc e i n ( k n ) figure (8): mortar rested on bricks with two dowel bars. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 figure (9): mortar rested on bricks with four dowel bars. figure (10): mortar rested on bricks with six dowel bars. shear force against slip for concrete to bricks w ith tw o dow els 0 5 10 15 0 2 4 6 8 10 slip in (m m ) s h e a r fo rc e i n ( k n ) al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 11 photo (2): concrete to bricks shear test photo (3): failure of concrete to bricks with six dowels photo (1): concrete to concrete shear test al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 298 seismic analysis of traditional jack-arch slab in south of iraq dr.abbas oda dawood dr.sa'ad fahad resan abbasoda03@yahoo.com sadresan@uomisan.edu.iq department of civil engineering engineering college university of misan amarah, iraq received 31 march 2015 accepted 21 july 2015 abstract jack arch slab is still widely used southern iraq although it is old roof system due to number of practical and economical advantages including simple construction technique, speed in construction, low cost availability of local labor skills. the study of seismic performance of this roofs in south of iraq is important due to the last earthquakes activity in iraq and relatively high earthquakes magnitudes of about 6 degrees according to richter scale, especially in misan province. static tests were conducted to determine the properties of clay brick and gypsum mortar used for jack arch slab in south of iraq, then the properties of masonry unit is obtained. the effect of camber configuration on ultimate strength and maximum deflection for both flat and 2 cm camber masonry arch specimens is investigated experimentally. the horizontal seismic loads is determined according to ubc while detailed procedure to determine vertical seismic load according to both ubc and iranian codes is presented due to its govern the design. finite element numerical analyses are then conducted using staadpro software to investigate the effects of a seismic loads on the behavior of slab and evaluate the safety of this type of roofs when subjected to seismic load. it is concluded that the flexural stresses are govern the behavior of jack arch slab not membrane stresses. based on finite element analysis, the compressive stresses developed in the slab are less than allowable stress but tensile stresses is critical, also the deflection and stresses of ipe steel beams is not exceed the allowable limits. keywords: jack arch slab; seismic analysis, vertical component, camber, flat slab, masonry العراق جنوب التحليل الزلزالي لسقوف العقادة التقليدية في د.سعد فهد رسن د.عباس عوده داود جامعة ميسان/كلية الهندسة/ قسم الهندسة المدنية الخالصة تنفيذية و مزاياالعراق على الرغم من كونها نظام تسقيف قديم و ذلك يعود لعدة جنوبي سقوف العقادة الزالت واسعة االستعمال دراسة السلوك إنو سرعة التنفيذ و الكلفة الواطئة و توفر العمالة الماهرة لها محليا. التنفيذ بساطة طريقةاقتصادية و التي تتضمن مهم و ذك للنشاط الزلزالي المتزايد في السنوات المنصرمة في العراق و الدرجة الزلزالي هذا النوع من السقوف جنوبي العراق الفحوص االستاتيكية لتحديد إجراء. تم محافظة ميسانعلى مقياس ريختر و خصوصا في درجات 6الزلزالية العالية نسيبا و التي بلغت al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 299 تم و منها تم تحديد خواص العقادة نظريا. إنشاء سقوف العقادة جنوبي العراق, في طابوق الطيني و مونة الجص المستخدمةخواص ال المركبة تم حسابالمقوس و المستوي. العقادة نموذج من بلية التحمل و الهطول األعظم لكل التقوس على قا تأثيرل التحري العملي كونها اإليرانيةو المدونة ubcللمدونة للزالزل وفقا لقوى الشاقولية المركبةبينما تم حساب ubcقوى الزالزل وفقا للمدونة ل األفقية staadproالتحليل العددي بطريقة العناصر المحددة باستعمال برنامج الحاسبة إجراءتم هي المركبة المسيطرة في التصميم. اجهادات االنحناء إنتم استنتاج تصرف سقوف العقادة و سالمة تلك السقوف عند تعرضها للزالزل. قوى الزالزل على تأثيرلتحري اجهادات االنضغاط حددة فان تحليل العناصر الم إلى نتائج استناد. الغشائية األجهاداتوليس على سلوك سقف العقادة هي المسيطرة اجهادات الشد حرجة. كذلك فان هطول الجسور الحديدية الحاملة للعقادة و األجهادات المتولدة المتولدة اقل من الحدود المسموحة و لكن فيها هي ضمن الحدود المسموحة. 1. introduction the primary function of floor and roof systems is to support gravity loads and to transfer these loads to other structural members such as columns and walls. furthermore, they play a central role in the distribution of wind and seismic forces to the vertical elements of the lateral load resisting system (such as frames and structural walls).the horizontal forces generated by earthquake excitations are transferred to the ground by the vertical systems of the building which are designed for lateral load resistance (e.g. frames, bracing, and walls). these vertical systems are generally tied together as a unit by means of the building floors and roof. in this sense, the floor/roof structural systems, used primarily to create enclosures and resist gravity (or out of plane) loads are also designed as horizontal diaphragms to resist and to transfer horizontal (or in-plane) loads to the appropriate vertical elements (naeim and boppana, 2001). the manner in which the total shear force is distributed to the vertical elements (walls) depends on the wall rigidity relative to the diaphragm rigidity. in buildings with flexible diaphragms, the distribution of shear forces to walls is independent of their relative rigidity. these diaphragms act like a series of simple horizontal beams spanning between the walls. a flexible diaphragm must have adequate strength to transfer the shear forces to the walls, but cannot distribute torsional forces to the walls in the direction perpendicular to the earthquake ground motion (eeri, 2011). for design purposes, diaphragms are usually treated either as flexible or rigid. it is general practice to consider the diaphragms made of cast in place concrete, precast with concrete topping, and metal deck with concrete fill as rigid while the diaphragms consisting of precast planks without concrete topping, metal deck without concrete fill, and plywood sheathing as flexible. obviously, a flexible diaphragm can not experience the rotation or torsion that occurs due to the rigid body rotation of a rigid diaphragm (naeim and boppana, 2001). 2. jack arch slab the traditional steel i-beam, jack arch flooring system was developed in britain towards the end of nineteenth century and was used extensively to cover large floor areas in factories and other industrial buildings. the technique spread eastwards and, by the middle of the twentieth century, it became a popular flooring system in parts of east europe, the middle east and the indian subcontinent. due to its technical simplicity, speed in construction and low cost, traditional jack arch slabs are still very popular in the middle east, where, not only industrial buildings and ordinary dwellings but also many high-rise steel and concrete framed buildings are floored by this method (maheri and rahmani, 2003). jack arch slab is steel beams that are covered by brick arches. they were used extensively in previous decades in iraq, iran and other countries. the results of past earthquakes in iran like boin zahra.1962, dashte bayaz.1968, rudbar.1990, bam 2003 showed that lack of integrity and rigidity are the main al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 300 deficiencies of this slab. moreover, this slab should be assigned to the flexible diaphragms based on iranian standard code no.2800 (mahdizadeh at al, 2012). the roofs and floors, which are rigid and flat and are bonded or tied to the masonry, have a positive effect on the wall, such as the slab or slab and beam construction be directly cast over the walls or jack arch floors or roofs provided with horizontal ties and laid over the masonry walls through good quality mortar. others that simply rest on the masonry walls will offer resistance to relative motion only through friction, which may or may not be adequate depending on the earthquake intensity (iaee, 1986). customary jack arch slab in south of iraq consists steel i-beam commonly ipe 120, and brick jack arch. the maximum span of i-beam is 4 m and the spacing between i-beams (jack arch span) is between 0.7m to 0.9 m (commonly 0.8m) as shown in figure (1). the mortar used in brick work is gypsum mortar. the interior face of the slab is covered by cement plastering while the exterior face is firstly covered by thin layer of gypsum mortar, then water proof thin sheets, then clean clayey soil layer sloped to discharge rain water. 2.1. behavior of jack arch slab the floor slabs constructed using the steel i-beam jack arch system are stable under normal static conditions as the brick arches transfer the gravity loads, mainly in compression, along the arch to the supporting beams, figure (2). the load is then transferred along the parallel steel beams to the supporting walls or beams. the geometric form of the steel i-beam jack arch system and the load path through the steel beams, make the slab act as a one-way system. despite the wide spread use of the jack arch slabs and their advantages, there are no particular procedures for their engineered design and there is no mention of the system in codes of practice. indeed, a search of the literature reveals no reference to any particular scientific research directed at studying this slab system or any attempts to provide an engineering basis for its design and construction. design engineers, using the jack arch slab in framed buildings, consider the brick arches as merely dead loads, carried by the steel beams, and are sufficient in designing the steel beams. this assumption ignores the role of brick arches in transferring slab loads and the resulting large stresses developed in them. despite the lack of a proper design basis and the poor performance of the jack arch system under earthquake loading, this type of flooring is still used extensively in many countries. the reason for this being a number of practical and economical advantages including simple construction technique, speed in construction, low cost and the ability to alter the slab after construction, when compared to conventional reinforced concrete or concrete beam-block slabs. the performance of the traditional one-way jack arch slab in a number of recent earthquakes in eastern europe and the middle east, particularly in iran, has generally been poor. collapse of a large number of jack arch slabs and damage to many more was reported from the romanian earthquake of 1990 (maheri and rahmani, 2003). 3. experimental work to determine material properties of jack arch slab no data on the strength and mechanical properties of the local type of masonry were available. for this reason, standard static tests were carried out on brick units, mortar and masonry. the experimental work consisted of two phases, the phase i which is concerned with physical and mechanical properties of used materials to supply sufficient information about local materials which are used to manufactured jack arch slab in iraq. phase ii related to testing strength of typical one way masonry arch specimens which commonly used in practice in south of iraq nowadays. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 301 3.1 material properties of brick and mortar the brick arches in south of iraq consists of local clay bricks joined together by a gypsum mortar. gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate (caso4·2h2o).the gypsum mortar composed of gypsum mixed with water. it is one of the oldest known types of mortar in iraq due to availability of its raw materials. it is the only mortar used for jack arch construction in iraq because it sets hard and quickly. clay bricks are the most commonly types of bricks in iraq because of availability of raw materials, low cost of production, appropriate to bear the forces, heat isolation, resistance to fire and atmospheric changes, their standard dimensions are (240 mm x 115mm x 75mm) according to iraqi specifications (is25, 2000). for gypsum mortar the tests are included mechanical and physical properties due to lack of data for this type of mortar in the literature. a cubes of 50*50*50 mm were used to measure the compressive strength in which an average value of 3 mpa was obtained. modulus of rupture was obtained by testing a prisms of dimensions 40*40*160mm in whcih an avergae value of 0.466 mpa was obtained. the modulus of elasticity of gypsum mortar is measured experimentally as the slope of the linear portion of stress-strain curve, which is equal to 1000 mpa, as shown in figure (3). the tests of bricks is limited to compressive strength and density due to good literature are available to find other properties like modulus of elasticity. the average compressive strength of clay brick is 10 mpa and the density is 1665 kg/m 3 . the modulus of elasticity for clay solid brick can be determined from available strain-stress curves in the literatures. kaushik et al (kaushik et al, 2007), presented equation eq.(1) to determine the modulus of elasticity of clay brick in term of compressive strength of the brick, thus according to eq.(1), for fb=10 mpa, then eb= 10*300=3000mpa. )1(f300e bb  3.2 material properties of masonry two specimens were fabricated and experimentally investigated to highlight the effectiveness of camber, the first one with camber of 2cm and the second with zero camber (flat). both specimens have length of 70 cm and width of 32 cm. a workable gypsum mixture is used to bind units together and fill the gaps between them. the inner face of the slab is finished with plaster layer from cement -sand mortar of ratio 1:3 (cement to sand) as commonly used in practice. for masonry unit (both bricks and mortar) the flexural bond strength between brick and mortar is investigated according to procedure used by (khalaf, 2005), see fig. (3). the average tensile bonding strength between clay bricks and gypsum mortar obtained from tests is 0.332 mpa. all one way masonry arch elements were tested under three-point load test, in which all loads were applied at mid-span of specimens. load was applied at the mid-span of the slab using a hydraulic jack having a capacity of 10 ton. the slab was simply supported at its ends. dial gauge was placed on the mid-points of mid span of the slab to measure the deflection as shown in fig. (4). the effectiveness of jack arch slab camber is investigated through both specimen's strength and deflection. the failure load and maximum mid-span deflection of camber slab is 3.554 mpa and 0.82 mm respectively, while for flat slab, the failure load and maximum mid-span deflection is 3.358 mpa and 1.184 mm respectively. the experimental results showed that for relatively small camber the strength was increased and the deflection was decreased which mean that jack arch slab performance al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 302 could be improved by increasing it crown camber. there is one failure mode for both specimens camber and flat, its characterized by suddenly flexural collapse of masonry arch. 4. theoretical estimation of masonry properties 4.1 theoretical estimation of masonry compression strength, f'm f'm is the intrinsic property of masonry which can be used in the design of a variety of masonry elements. f'm is also used to estimate em and for plotting the masonry stress-strain curves. therefore, f'm is one of the most basic and required properties which must always be available for a given masonry. however, it is not always feasible to conduct compression testing of masonry prisms. on the other hand, fb and f j are readily available in the design codes or can be obtained easily by conducting tests. the three compressive strengths can be conveniently related as done in eurocode6 as (kaushik et al, 2007): )2(ffkf mbm   where fb : compressive strength of bricks, mpa; fm: compressive strength of mortar, mpa;f'm : compressive prism strength of masonry, mpa; k: constant depending upon brick properties and brickmortar joint configuration; α, β: constants representing contribution of bricks and mortar compressive strengths on f'm kaushik et al (kaushik et al, 2007), proposed the following equation to estimate the masonry prism compressive strength from the compressive strengths of bricks and mortar obtained experimentally. )3(ff63.0f 32.0 m 49.0 bm  they found that equation proposed by eurocode6 eq.(2), is good for masonry constructed with high strength bricks, however for lower strength bricks, the error in estimating the masonry compressive strength is comparatively higher. the estimation of masonry compressive strength using eq.(3) proposed in their study is consistently better for prisms made with low and medium strength bricks. thus in the present study masonry compressive strength is determined using eq. (3). thus for fb=10 mpa and fm=3, then mpa.**.f .. m 772310630 320490  4.2 theoretical estimation of masonry modulus of elasticity and poisson’s ratio the modulus of elasticity of masonry depends on the modulus of elasticity of the mortar and the unit as well as the volumetric ratios of the constituent materials. in reality, the modulus of elasticity of masonry varies for different directions and loading conditions (özen, 2006). empirical linear relationships between the compressive elastic modulus and the equivalent compressive strength from some researchers are usually assumed as follows (wijanto, 2007) )4(fke mm  where k is a constant factor, em is elastic modulus of masonry in compression (mpa) and f’m is specified compressive strength of masonry (mpa). k factor for clay bricks varies from 300 ≤ k ≤ 750. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 303 this huge range factor is depend on the local raw material of clay brick (wijanto, 2007). some methods relate the modulus of elasticity of masonry to the masonry geometry and the material properties. one of these methods is (özen, 2006): )5( )1()1( 2 1 22             b b m m bmbmbm bmmb bm m m b b m eeee ee eee      where, ηm, ηb : are the volume fractions of mortar and brick, em : is the modulus of elasticity of the masonry, eb, em: are the modulus of elasticity of the brick and the mortar, νb, νm: are the poisson’s ratio of the brick and the mortar. the volume fractions of the brick and the mortar can be calculated by using the following equations; )6( tt t , tt t mb b b mb m m     where, tm: is the thickness of the mortar, tb: is the thickness of the brick. in present study the modulus of elasticity of masonry is determined suing eq. (5) due availability of experimental data for brick and gypsum mortar. thus for eb=3000 mpa and em=1000 mpa, then em=2586 mpa. poisson’s ratio of most hydraulic cement and lime mortars is on the order of 0.2 (wijanto, 2007). francis et al (francis et al, 1971)obtained the value of poisson's ratio of 0.25 for both solid and perforated clay bricks . the poisson’s ratio of masonry is generally between 0.2-0.25 (özen, 2006). in present study a poisson's ratio of 0.2 , 0.25, 0.22 is used for mortar, clay brick and masonry respectively. 5. allowable stresses of jack arch slab the failure for the jack arch slab is either failure of steel beams or failure of brick arches. the bending failure of the steel beams is govern its behavior. the compressive failure of the brick arches is govern if the there is suitable camber, so that brick arches transfer the load to steel beam by arches compression action in which membrane stresses developed in the brick arches. in traditional jack arch slabs in southern iraq it is either flat slab or with relatively small camber of 2 cm, so that the brick arches behave as bending plate and the flexural stresses is govern it is behavior. the flexural failure was govern the jack arch slab behavior which is clearly appear in the experimental investigation of tested specimens, in which the failure of specimens were mainly due to bottom tensile stresses. the arches were not reached to the compressive capacity which mean that the compressive membrane stresses are low . to investigate the stress distribution of experimentally tested specimens, a three dimensional finite element model for jack arch slabs (flat and camber) at failure loading conditions was accomplished. the stress distribution of flat and camber slabs at failure loads are shown in fig. (5), in which the flexural stresses are govern in both flat and camber slabs. in flat slab membrane stresses is zero while in camber flat there is relatively low membrane stresses in comparison with flexural stresses . the distribution of stresses shown in fig. (5), is compressive stresses at top and tensile stresses at bottom with maximum values at mid-span. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 304 the allowable compressive stress for flat jack arch slab is assumed as given by ubc code (ubc, 1997) for masonry wall, namely: )7(f16.0f mall,m  while for jack arch slab with camber, due to the loading situation and the geometry of the arch, an increase in compressive stress (increase in load) will cause an increase in the stability of the arch. for this reason, (maheri and rahmani, 2003) proposed that the allowable compressive strength for jackarch construction could be found from the following equation. )8(f2.0f mall,m  the tensile failure in brick arches is governed by the bond tensile strength in case of slab with camber. while in case of flat slab the tensile flexural strength is govern. thus for camber slabs the tensile strength is 0.332 mpa based on bond strength obtained experimentally. while for flat slabs the allowable tensile stress for can be determined indirectly from flexural tests results, in which flexural tensile strength is 0.327 mpa. thus an average value has been taken, then tensile strength for both camber and flat slab is 0.33 mpa, then the allowable tensile stress is )9(mpa33.0f all,t  the allowable stresses for steel is determined by codes of practice namely aisc-asd (aisc, 2006), in which allowable flexural tensile or compressive stress for steel is assumed to be: )10(f6.0f yall,s  thus the compressive allowable stresses for f'm=2.77mpa, is 0.443 mpa and 0.554 for flat and camber slabs respectively, the allowable tensile stress is 0.33 mpa for both slabs, while for steel beams the allowable stress is 140 mpa. 6. loading loading to be considered in the design of jack arch slabs, are gravity and earthquake loads. the masonry is very strong under compression forces therefore, masonry structures are usually very resistant to gravity loads. earthquake loads and differential settlements of supports are usually the main reasons for the damage or collapse of masonry structures (özen, 2006). the gravity, service dead and live loads may be determined using appropriate codes of practice, according to iraqi code for loads and forces (is301, 2014), a live of 1 kn/m2 is appropriate for jack arch slab buildings. the earthquake loads, acting on a jack arch slab are in-plane horizontal loads and out of plane vertical loads. in the present study the horizontal and vertical earthquake loads are determined using equivalent-static method. load combinations for allowable stress analysis based on ubc code (ubc, 1997) is given in eq.(11), in which worst case should be considered in design. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 305 4.1 e d9.0 )11( 4.1 e ld ld    the earthquake have two components horizontal and vertical. the earthquake-induced horizontal forces acting on the slab may be either in-plane axial or in-plane shear forces as shown in fig. (6). the majority of stresses developed in the slab are due to the combined effects of gravity and vertical earthquake load. 7. determination of earthquakes loadings by equivalent static method there is no specific criteria for seismic loadings on jack arch slab in codes of practice. thus several modifications will be accomplished on codes procedures to take into account jack arch slab properties especially in vertical earthquake loadings. from these procedures and based on materials properties measured, the seismic loads on jack arch slab in south of iraq are determined. the horizontal and vertical earthquake loads are determined by equivalent-static method using procedures of ubc 1997. a modifications has been accomplished to determine the vertical earthquakes loads on jack arch slab based on ubc 1997. also the vertical loads on jack arch slab is determined using procedure presented by maheri and rahmani (maheri and rahmani, 2003) which is based on iranian seismic code. maysan province lies on the iraq-iran borders therefore, seismic design data like peak acceleration could be obtained from iranian seismic code. 7.1 determination of horizontal earthquakes loadings by ubc 1997 procedure according to ubc 1997 (ubc, 1997) section 1653, baghdad area is considered as seismic zone 3 while basra as zone 2. because maysan province has seismic hazards in last years more than baghdad, thus according to ubc classifications maysan province is considered as seismic zone 3. all jack arch buildings in iraq either one-story buildings or two-stories buildings , thus the equivalent static lateralforce procedure (ubc 97 sec.1630.2) can be used to determine the seismic loads. the total design base shear (v) in a given direction shall be determined from the following formula (ubc 97 sec.1630.2.3.2): )12(w tr ic v v  the total design base shear need not exceed the following: )13(w r ic5.2 v a  the total design base shear shall not be less than the following: al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 306 )14(wic11.0v a where ca and cv are seismic coefficients defined in tables 16-q and 16-r of ubc97 respectively (ca and cv for zone 3 and maysan soil type is equal to 0.36 and 0.57, respectively). maysan soil type is considered as sd type according to ubc classifications (table 16-j ubc97). , i is occupancy important factor (i=1, table 16-k ubc97), r is a factor defined in table 16-n, t is fundamental time period and w total weight of structure. for jack arch slab problems in south of iraq eq (13) is govern due to low rise building with this type of construction. the forces at each level shall be calculated using the following formula: )15( hw hwv f n 1i ii xx x    where wx , wi are portion of w located at or assigned to level i or x, respectively and hx , hi height in feet (m) above the base to level i or x, respectively. seismic forces on floor and roof diaphragm fpx at level x is determined from following equation (ubc sec. 1633.2.9) )16(w w ff f pxn xi i n xi it px       where fx , fi are design seismic force applied to level i, or x, respectively, ft = 0 for t< 0.7 sec. also ubc specify the following limits on fpx )17(wic0.1fwic5.0 pxapxpxa  the weight, wpx , includes the weight of the diaphragm plus the tributary weight of elements normal to the diaphragm that are one-half story height below and above the diaphragm level. walls parallel to the direction of the seismic forces are usually not considered in the determination of the tributary roof weight because these walls do not obtain support in the direction of the force, from the roof diaphragm (seaoc, 1999). according to ubc code table 16-n the r-factor for masonry bearing wall building (with masonry shear walls as lateral force resistance system) is equal to 4.5, but in section1633.2.9 of ubc code rfactor should not exceeding 4 for flexible diaphragms providing lateral supports for walls or frames of masonry or concrete. thus for jack arch slab which consider as flexible diaphragm the r= 4. for a customary jack arch buildings in south of iraq building have similar structural systems along different plan axes (i.e., directions) of the building in which the buildings have masonry shear walls in both al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 307 directions. therefore r have the same value in both directions. the structural period t may be approximated from the following formula:   )18(hict 4/3nt where ct = 0.0488 for jack arch slab, hn = height in meter above the base to level n. total weight of structure, w, is the total dead load and applicable portions of other loads. thus according to eq. (13) the total design horizontal base shear in a given direction, in term of seismic dead load, w, is summarized in table (1). 7.2 determination of vertical earthquakes loadings by ubc 1997 procedure the total design vertical earthquake load can be determined using the same equations for horizontal loads eq. (13), but using the following modifications for some parameters. ca and cv coefficients are determined for the horizontal earthquake loading, thus it should be modified for the vertical loading. design seismic vertical acceleration parameters can considered as 2/3 from horizontal acceleration parameters. r is numerical coefficient depends on lateral force-resisting systems (ubc, 1997), thus for horizontal load it can be easily found from ubc code (table 16-n, ubc). but for jack arch slab, r, should be modified. the jack arch slab system may be considered as a confined masonry construction. for confined masonry walls, a value of 4 is often used for r factor, but the jack arch slab system is expected to behave differently to a conventional masonry building system. maheri and rahmani (maheri and rahmani, 2003) derived an approximate value for r for one-way and two-way jack arch slab based on ubc code formats. they concluded r = 2.0 may be considered for one-way jack arch slab system [1]. thus here r taken to be equal to 2.0 for vertical loadings calculations. the design vertical component of seismic loads is summarized in table (1). 7.3 vertical earthquake force on jack arch slab using iranian code procedure this procedure is proposed by maheri and rahmani (maheri and rahmani, 2003) based on iranian seismic code (iranian code, 2007) using equivalent-static method (in this study this procedure is referred to as iranian procedure). they proposed specific values for seismic parameters to be applicable for jack arch slab buildings. their procedure is summarized as following. this method is based on iranian seismic code, the earthquake load, e, is related to the weight of the system, we, in the following form: )19(wce e we, is usually considered as the total dead load plus a percentage of the live load. the earthquake coefficient, c, may be determined from the relation: (20) w r iba c  al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 308 in which, a, b, i and rw are the design base acceleration, the dynamic response coefficient, the importance factor and the performance factor, respectively. they considered the performance factor, rw, for the one-way system as 2.0 (maheri and rahmani, 2003). for design of jack arch slabs, the importance factor, i, may be taken as that for the whole building. the design base acceleration, a, is given by seismic codes for different localities. this coefficient is, however, determined for the horizontal earthquake loading and should be modified for the vertical loading. a 33% reduction is often used for this conversion. for jack arch slab, the fundamental mode of vibration is considered for the first out-of-plane bending mode. they determined structural period t, for the jack arch slabs, by assuming the slab as a linear, elastic rectangular plate bending element, the classic solution for the fundamental bending mode of vibration is given in the following form (maheri and rahmani, 2003): )21( v1(12 he a2 t 2 m 3 eff2 1 2     in the above equation, a, h, eeff , ρ and vm are length, thickness, effective elastic modulus, mass per unit area and poisson’s ratio of the plate, respectively and λ1 is a dimensionless parameter depending on the geometry of plate and its boundary conditions. to be able to apply this equation to a non-homogenous composite plate, such as a jack arch slab, they used equivalent effective parameters. the effective thickness, h, is considered as the full thickness of the flat slab, including flooring and the effective density, ρ , determined considering slab materials.. poisson’s ratio is considered to be the same as that for masonry due to the effect of poisson’s ratio is small. the effective elastic modulus, eeff, of the slab has an appreciable effect on the fundamental period of vibration. the parameters affecting the eeff of the slab are the dimensions and boundary conditions of the slab, the elastic modulus of brick arches and the number, and size and configuration of the steel beams. they found that the effective elastic modulus of slab, eeff, is linearly proportional to the elastic modulus of masonry, em. as for the slab boundary conditions, the results from the worse case scenario, i.e. the simply supported situation, are used. the best parameter to represent the other two variables, i.e. dimensions of the slab and steel grid configuration, is the weight of steel per unit area of slab, ws (kg/m 2 ). the results of these analyses are plotted in fig. (7). in this figure, the ratio of effective elastic modulus of slab to elastic modulus of masonry (eeff/em) is plotted against ws. the dynamic response coefficient, b, could determined from the diagram given by the iranian seismic code which shown in fig. (8). the actual values of b for the four different soil types are calculated and plotted, in the fig. (8). according to iranian code maysan province soil can be consider as type iii.the design vertical component of seismic loads for both ubc and iranian procedure is summarized in table (1). 8. finite element investigation of jack arch slabs to investigate the behavior of the jack arch system in south of iraq, a finite element models were accomplished to represent the real systems for both flat slabs and slabs with 2 cm camber. the finite element linear stress analyses of the slabs were carried out using the general-purpose, staadpro al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 309 program (staad pro, 2008) beam elements were used to model beams and shell elements were utilized to model the brick arches. the dimensions investigated roof has steel beams of 4m span as commonly used southern iraq, the spacing between steel beams is 0.7m, and roof dimensions 3.5m*4m. dead load includes masonry slab weight, steel beam weight, and roofing weight. live load is taken as 1 kn/m 2 which suitable for this construction. in calculation horizontal seismic loads the total weight w according to ubc code is equal to dead load plus half weight of normal walls for each direction x and z. in calculation vertical seismic component (y-direction ) only dead load of slab is considered according to ubc procedure while adding 20% of live according to iranian procedure. the analyses were accomplished for all possible loads combinations as shown in table (2). the typical stress contour for both flat and camber jack ach slabs are shown in fig. (9). from the results of internal stresses of jack arch slab shown in table (2) it is clearly that the vertical component of seismic load is govern the design of jack arch slab. the horizontal components of seismic loads have small influence on the behavior of jack arch slab as shown in table (2). the maximum compressive stress in case of horizontal seismic load in x-direction (normal to steel beams) in increased by about 3.5% more than gravity stresses for both flat and camber jack arch slabs, while the maximum tensile stresses is increased by about 3.5% more than gravity stresses for flat slab and stay equals for camber slab. in case of horizontal seismic load in z-direction (paralell to steel beams), the maximum compressive stress in increased by about 6.7% and 3.5% more than gravity stresses for flat and camber jack arch slabs respectively, while the maximum tensile stresses is decreased by about 3.6% and 7.4% less than gravity stresses for flat and camber jack arch slabs respectively. the maximum stresses developed in steel ipe beams is 69 mpa which is much less than the allowable stresses (140 mpa), also the maximum mid-spa deflection of steel beams is 7.7 mm which much less than maximum allowable out-of-plane deflection (l/360 =4000/360 = 11.11 mm). thus the steel beam deflections and stresses is not critical in traditional jack arch system in south of iraq under both gravity and seismic loads. thus the critical part of jack arch slab is masonry arches. thus the critical case of seismic ad gravity combinations is vertical components of earthquake with dead load combinations. the maximum tensile stresses in case of vertical seismic component and dead according to ubc code procedure is more than gravity stresses by 25% and about 19% for flat and camber jack arch slabs respectively. according to iranian procedure, the maximum tensile stresses is more than gravity stresses by 7% and about 3.7% for flat and camber jack arch slabs respectively. in comparison the tensile stresses of vertical component and dead load combination obtained from both ubc code procedure (0.35 mpa and 0.32 mpa for flat and camber respectively) and iranian code procedure (0.30 mpa and 0.28 mpa for flat and camber respectively), with experimental measurements of tensile bonding strength of 0.332 mpa and modulus of rupture of 0.327, its clearly that the iranian procedure more realistic than ubc code procedure which gives more conservative results due to iranian procedure take into account characteristics of jack arch slab like r-factor value, effect of steel beams on modulus of elasticity of masonry which is not accounted in ubc code. in comparison stresses values with allowable stresses its clearly that only tensile stress is critical, in which in several cases the resulted stresses exceed allowable stress but still below tensile strength of masonry slab, therefore the tensile strength of the slab can be improved using wire mesh which cheap and easy improvement. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 310 9.conclusions the following conclusions can be drawn from the present study: 1the jack arch slab with camber not less than 2 cm has less deflection, higher ultimate load, less stresses than flat jack arch slab under both gravity and seismic loadings. 2the vertical component of seismic loads is govern the design of jack arch slab southern iraq, and the horizontal components of seismic forces have negligible effects on stresses, deflections and design of jack arch slab in comparison with gravity loadings. 3for camber slab, tensile strength should be obtained by bond tensile strength, while in case of flat slab tensile strength could be obtained by tensile flexural strength similar to modulus of rupture of concrete. 4the tensile strength of flat slab obtained by both bond tensile strength and flexural tensile strength is closed namely 0.332 mpa and 0.327 mpa respectively. 5the iranian procedure presented by (maheri and rahmani, 2003) is more reasonable than ubc procedure in calculation seismic loads on jack arch slab due to ubc not take into consideration this type of roofs and iranian procedure present good and practical estimations for some parameters like r factor and participate of steel beams in slab stiffness so its recommended to use iranian procedure presented in this study when deign jack arch slab to seismic loads southern iraq. 6the maximum tensile stresses for gravity loads are 0.28 and 0.27 and for seismic loads are 0.35 and 0.32, for both flat and camber slabs respectively, which is close to the allowable value of 0.33 mpa, thus the tensile strength of jack arch slab is critical under both gravity and seismic loads. 7the maximum stresses and deflections of steel ipe beams obtained from finite element model are 69 mpa and 7.7 mm respectively, for commonly used 4m as a maximum span of steel ipe steel beams carried jack arch slab southern iraq, these values are within allowable limits of140 mpa and 11.11 mm for stresses and deflections, respectively. 8according to the experimental investigation of tested specimens, the failure of specimens were mainly due to bottom tensile stresses. thus for traditional jack arch slabs in southern iraq is either flat slab or with relatively small camber of 2 cm the brick arches behave as bending plate and the flexural failure is govern it is behavior. references maheri m. r. and rahmani h. , 2003 " static and seismic design of one-way and two-way jack arch masonry slabs" engineering structures 25 (2003) 1639–1654, elsevier ltd. mahdizadeh, a., borzouie, j. and raessi m., 2012 "new approach to seismic rehabilitation of masonry school buildings" the 15th world conference on earthquake engineering, 15 wcee, lisboa, portugal. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 311 iaee manual, international association for earthquake engineering ,1986 "structural performance during earthquake", chapter two, iit kanpur, india. naeim f. and rao boppana r., 2001" seismic design of floor diaphragms" the seismic design handbook, chapter 8, kluwer academic publisher. structural engineers association of california , seaoc, 1999 "seismic design manual: volume i code application examples" california, usa. earthquake engineering research institute, eeri, 2011 " seismic design guide for low-rise confined masonry buildings" oakland, california, eeri publication number whe-2011-02. kaushik, h. b., rai , d. c. and jain, s. k., 2007 "stress-strain characteristics of clay brick masonry under uniaxial compression" asce, journal of materials in civil engineering , vol. 19, no. 9, september 1, 2007. özen g. o. , 2006 "comparison of elastic and inelastic behavior of historic masonry structures at the low load levels", msc. thesis, middle east technical university, ankara turkey. wijanto l. s., 2007 "seismic assessment of unreinforced masonry walls" ph.d thesis, university of canterbury, christchurch, new zealand. . francis a. j., horman c. b. and jerrem l. e., 1971 " the effect of joint thickness and other factors on compressive strength of brickwork" proceedings of 2nd, international brick masonry conference, british ceram. fouad m. khalaf, 2005 "new test for determination of masonry tensile bond strength", journal of materials in civil engineering, vol. 17, no. 6, pp. 725–732. uniform building code ,ubc, 1997 " earthquake design" california, usa. iranian code,2007 "iranian code of practice for seismic resistant design of buildings", standard 2800, 3rd edition, building & housing research center,islamic republic of iran. american institute of steel construction, aisc, 2006 "steel construction manual"13 edition, usa. iraqi standards, is25, 2000, "iraqi standard no.25, is25" iraqi standards no.301, is301, 2014, "draft of loads and forces code" ministry of housing and construction, iraq. staad pro v8i, 2008 "structural analysis and design computer program" bentley company, usa. http://en.wikipedia.org/wiki/structural_analysis al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 312 table (1): horizontal and vertical seismic loads based on ubc and iranian procedure code load w horizontal load by ubc 1997 procedure 0.225 w 1630.1.1: only dead load vertical load by ubc 1997 procedure 0.3 w vertical load by iranian procedure 0.183we 2.3.1: dead load+20%live load table (2): results of finite element investigations load case direction load comb. max. slab compressive stress, mpa max. slab tensile stress, mpa max. steel stress, mpa maximum ipe steel deflection, mm flat camber flat camber flat camber flat camber 1 vertical d+l 0.28 0.28 0.28 0.27 62 58.8 7.53 7.3 2 horizontal d+l+ex/1.4 ubc code 0.29 0.29 0.29 0.27 62 59.2 7.53 7.4 3 horizontal d+l+ez/1.4 ubc code 0.3 0.29 0.27 0.25 62 58.7 7.53 7.3 4 vertical 0.9d+ey/1.4 ubc code 0.11 0.14 0.11 0.14 19 18.7 2.9 2.8 5 vertical 0.9d-ey/1.4 ubc code 0.35 0.35 0.35 0.32 69 65.5 7.9 7.7 6 vertical 0.9d+ey/1.4 iranian code 0.14 0.14 0.14 0.15 27.7 26.5 3.7 3.6 7 vertical 0.9d-ey/1.4 iranian code 0.3 0.3 0.3 0.28 62 57.7 7.03 6.9 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 313 figure (1): traditionally jack arch slab in south of iraq figure (2): construction details of traditional jack arch slab in iraq beamsteelipe flooring brickarchbrickflat slabarchjackflat slabarchjackcamber al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 314 figure (3): brick and mortar specimens figure (4): flexural tests of jack arch slab specimens flat slab camber slab mortar comp. strength mortar modulus of rupture mortar modulus of elasticity masonry bond strength brick comp. strength al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 315 figure (5): three dimensional finite element models for jack arch slab specimens figure (6): the earthquake-induced horizontal forces acting on the slab ain-plane axial loads perpendicular to the steel beams bin-plane shear parallel to the steel beams al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 316 figure (9): typical stress contours of jack arch slab figure (7): the effective modulus of elasticity (eeff) of the jack arch slab, (maheri and rahmani, 2003) figure (8): the proposed dynamic response coefficient b for jack arch slab, (maheri and rahmani, 2003) 1-المقدمة: 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 12 استراتيجيات تطوير مخّيمات الالجئين الفلسطينية في قطاع غزة -حالة دراسية – لالجئين يونس م خانمخيّ د.م/ نادر جواد الّنمرة بناء المشارك وتكنولوجيا ال المعماري أستاذ التصميم –كلية الهندسة بالجامعة اإلسالمية -قسم الهندسة المعمارية غزة، فلسطين nnamara@ iugaza.edu.ps 2024آيار 22ُقبل 2024آذار 6ُأستلم  :ملخص البحث بشلللعخ لللج شلللجاًنع ىجفملللجع نللل ملللج للل 2491تمثلللخ مماتملللجئ ن الفلللان ن منذلللساساا مسللل ت ذاذللل ج لللج ذللساسان مللن نىللتاي ،تشلل اًه عمللج فس للج تمثللخ رللا ن ،ىللئ سمذللم مللقنع منجسللجت ه ،ملل تا لل ن للقمن ،تسلل،ت بج من اللجً للًً ن ذللعجن رللان ن مماتمللجئ ن منذللساساا رللا ىسللجي شللقو تسجمللئ ،نعت للئ بشللعخ اجفللخ ، تللقنخ ن اللجو ،نًق منجً للا ن رالل ن مت،نقسللا بللان ف للًنً ن ضللجف ا ن ذللعتجساا ،ن مًمجتاللا ن ممتنمللا متًساللا ،رللا تنللج مذللتم ب علل ن ن ذعجن ،مذج ا نأل ض ن ممصتصا تنك ن مماتمجئ. ، ً تسج،خ ن بج ث مس لاا نماا ن تمًئ ن ن ،صف ن ت نانلا ن،صل،خ ن ل الًف ن ً نذلا ،ال، ،ضل خ ملج نذت نتالاجئ تس،ا مماتمجئ ن الفان ن منذساساا را ىسجي شقو بشعخ ج ،ممات مجن ال،س بشلع ع ج ا ً نذااه ، ً شمنئ ن ً نذا ف بنا م ج، فاذاا تمثتنئ را: ن م ، نأل،خ اث تسج،خ ن ممجاا ن نجما رامج اتنن بم،ضل،ي ن ً نذلاه فملج ن م ل، ن ثلجسا رتسلج،خ ً نذلا مماتملجئ ن الفلان ن منذلساساا بشلعخ لج ملن جئ ن نجما نمماتمجئه فملج ن م ل، ن ثج لث رتسلج،خ ً نذلا اث ن مم ، ،ن سش و ،نأل،ضجي ن ًام،ش نراا ،نإلشعج ا ممللات مللجن اللل،س الفللان ع ج لللا ن ً نذللاا ، لللك مللن اللث ن ً نذلللجئ ن متننت للا بلللج تمساس ،ن تصللما ،ن بسالللا ن ت تتاا ،ن ً نذجئ ن ذعتجساا ،ن لتمج اا ،نإلشلعج اجئ ن نجملا نمملات ه فملج ن م ل، ن نبل ،نألمال رتسلج،خ ستلجف ً نذا ،ن ت،صاجئ ن م ت ا نتس،ا .ن  :كلمات مفتاحية مملللات ملللجن -ن مماتملللجئ ن منذلللساساا -اافلللا نألمللل ن مت لللًو ،سللل ،ننأل -ن الفللل،ن -تسللل،ا -نذلللت نتالاجئ ا،س . 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 development strategies for refugee camps in the gaza strip khan younes camp as a case study dr. nader el namara associate professor, architectural design & building technology department of architectural engineering, islamic university of gaza, palestine nnamara@iugaza.ede.ps abstract: since its establishment in the 1948, the refugee camps represent a clear symbol of what palestinians have encountered, especially the deportation from their own lands. at the same time, it represents the symbol of their continuing tragedy. as time passes and life goes on, the number of inhabitants rapidly increases, thus the refugee camps became more crowded. this situation led to the fact that public services and residential units available became insufficient due to the limited available land. the research adopts a descriptive analysis approach to come up with effective strategies to develop the refugee camps in the gaza strip, in general and khanyounes camp in particular. the research study is composed from four pieces of writing. the first point gives a theoretical background of the discussed topic, while the second point concentrates on giving an overview about the refugee camps including, history, demographic circumstances, and main problems facing its development. the third point focuses on the case study, which is khanyounes camp in terms of urban planning and design, in addition to socioeconomic studies and main characteristics. the last point concludes findings and recommendations for further research studies.  :أهمية البحث تعمن فاماا ن ب ث را فن مماتمجئ ن الفان ن منذلساساا الا ،نىل امثتلخ ىضلاا ن شلنس ن منذلساسا ن ل (2 امعللن را لللج ن ترجضللا لللن فن ن مماتملللجئ اللا ن شلللجاً ن ، الللً نلل منالللجئ ن ت لاللل رللا للل شلللنبسج و ر لل ًاللج ج ،ف نضللام ن تللا التلل م نلل فاللً 2491س للج للج ن منذللساسا ، نلل للم ن مشلل ،ي رللا ن نللً، ن تاخ نإلذ نفانا. تعملن فامالا ن ب لث رلا فن ن ممسلس نإلىناملا سلجي شلقو ن تملً مًاسلا ملجن ال،س عم علق رىناملا ثللجسا (1 بنً مًاسا شقوه ،بج تج ا رلان ن اتملج بمملات ملجن ال،س نل شل ن ن اتملج بمملات ن شلجس رلا مًاسلا نء ،عمجءو مًاسا مجن ا،س .شقو ا، من فا ف، ،اجئ ت ذان فً ا تخ ممات مجن ا،س ن لجسس ن ر با من ن مًاسا ،انا تمًتًاج ن نم نسا ل ا ن ر سه ،بج تج ا بً من (3 (.22،ض نذت نتالاجئ جما تس،ا ج عمج ا،ضت ج ن شعخ) mailto:nnamara@iugaza.ede.ps mailto:nnamara@iugaza.ede.ps 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 13  :أهداف البحث ن تن تف ن مماتمجئ ن الفان ن منذساساا را ن ًنمخ ،ن شتجئ. (2 ن مصجف ،ل،نسس ن ص، را ن تمساس ،نإلسشجء ًنمخ ن مماتمجئ ن منذساساا.ن تن تف (1 ن ممتنما ن عجرا ن مذت،اجئ إلذ ج را تس،ا ن مماتمجئ. ئ،ض ن ذت نتالاج (3 تثبائ ا ج ن ً نذا ،ستجفل ج عم ل نما امعن ن ذتمجًو مس ج را ملج ئ ا ن ن ب ث. (9  :المشكلة البحثية جئ ن الفلللان ن منذلللساساا رلللا ىسلللجي شلللقو بشلللعخ لللج ملللن ن تلللًا، رلللا نأل،ضلللجي ن ذلللعجساا تنلللجسا مماتمللل ،ن مًمجتاا ،ن بساا ن ت تاا ،ن نًاً من نألم، ن ممتنماه ،بج تلج ا رلان اسلجك جللا من تلا ،ضل ن ذلت نتالاجئ رللا للخ للً للخ تسلل،ا تنللك ن مماتمللجئ نلل عجرللا ن مذللت،اجئ بناللًنع للن رس جف للج ف، ،ضلل نلل،خ إلس جف للج و ن الفلللان ألن رس جف لللج امثلللخ رس لللجء ن ضلللاا ن منذلللساسااه ، لللً تمثتنلللئ ن ضلللاا ن منذلللساساا ،تسباللل للل لللً، -ن مشعنا ن ب ثاا را نآلتا: رللا ىسللجي شللقو م،مللجع ،ممللا مللجن الل،س مص،صللجع ،نرت للج ج نتللًا، ن ،نىلل ن ذللعجسا الفللان ن منذللساساا" ". نإلسذجسااألبذس ن م ،مجئ ن اجتاا ،  :منهجية البحث راملج اتننل بم،ضل ن ً نذلا ، لك ملن ت نانان اصمنتب ن بج ث مس لاا نماا ن تمًئ ن ن مس ن ، للبنض ن مماتمللجئ نلل ه رضللا للن ن قاللج نئ ن ماًنساللا ن ب للث رللا ن م نللل ،ن عتللس ،نألب للجث ن ممتنمللامللاخ ،ن ل جئ ن جفملا ،ن منسالا ب ل ن ن مللجخ مثلخ ،قن و ن تمسلاس ،م علق ،قاج و ن ،قن نئ ،ن مؤذذجئ مذت،ى ن سجي ( ،شا اللللج ،صللل، ع ر لللل ن ستللللجف ،ن ت،صللللاجئ ،سلللل ،ننألنإل صلللجء ن منذللللساسا ،،عج للللا شلللل،ث ،تشلللراخ ن الفللللان ) ن مجصا ب ًف ن ً نذا .  :هيكلية البحث ( ااعناا ن ب ث ضمن ف ب م ج، : 2ا،ضتح ن شعخ) اا ن ب ث(: ا،ضتح ااعن2شعخ) ن بج ث -ن مصً -حالة دراسية – لالجئين يونس م خانمخيّ المحور الثالث ور األولالمح فاهيم عامةم الفلسطينية الالجئين ماتمخيّ محور الثانيال المحور الرابع والتوصيات النتائج الفلسطينية في قطاع غزة الالجئين ماتمخيّ استراتيجيات تطوير -حالة دراسية – لالجئين يونس م خانمخيّ 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 19  :مقدمة تن تضئ رنذسان ععاجن ذاجذا نمناا تًما شجمنا ستاللا ىالج ن لتاخ ن نلً، نإلذل نفانا ألعثل ملن ثنثلا ف نضا ج ر ًئ من ما ج ن مًن ،ن ى ،نأل نضا ،مصجً ن ماجج ،ن م ماتجئ ن سبانااه نألم ن ل فًى ر ل ا ن مسجرا ،ن شتجئ ،ر ًنن ن ملتمل ن منذلساسا م ،مجتلم ،تلًما شج بالا ن مس ،ملا ن لتمج الا تش اً ذعجس ج ر مضج نمناجئ ن تشتائ ن ذ را م،نى لر نراا تمثتنئ رامج ا تا -:]21 [،ن ،ا ن ان تسن نا رذ نفاخ " س رذ نفاخ " ،ا من،ن ن لسذاتا نإلذ نفاناا. 91 س ف نضا -شا ل -ن نألصنا،ن را ن ضما ن ر باا ،ىسجي شقو ،ا ن ان اسن نا نذ "ن م،نسسان" ن ذعتج ن الفلل،ن ن منذللساسا،ن ،الل ن لل ان تلل تشلل اًا مللن ف نضللا رنللل لللقء مللس نللً،خ ن ن باللا ن ملللج، و ،لللقء آم ر ن ضما ن ر باا ،ىسجي شقو اث ذعس،ن ن مماتمجئ ن منذساساا. -عامة: مفاهيم .2  :أواًل/ الالجئون الفلسطينيون رنلفل،ن ًنملخ 2491ا ن ان ت ت تش اًا من ف نضا ،مًس ،ى نا ىبخ ف، ماخ ف، بنً س لج ن(ه رنذللسان )ن ضللما ن ر باللا ،ىسللجي شللقو( ف، ر لل ن مللج ع اللث ن للً،خ ن ن باللا ن ملللج، و )ذلل، اجه بسللجنه نألً فمللج ه ]21 [ لل مللن نأل ض نذللت ل ت ج نألملل ن مت للًوه فسنلل نا للج نذلل "ن ممللات "ر ىللجم،ن ًنمللخ ن ماللج نلل ب ستالا ن ل س لن ملًس ،ىل نا ر ل ن ضلما ،ىسلجي شلقو رن لً تل تذلمات )بسلجق ا 2411ن ان سق ،ن ج 11)] 21[.  :ثانيًا/ هيئة األمم المتحدة تبنجع ه سش ئ س ن س ن نج ماا ن ثجساا ت ابجع من لما ً،خ ن نج متمثنا ب ضجءاا مس ما ج ماا ه م عقاج ن ًنف را سا،ا، كه شجات ج م ن ذا ن ً را ن نجصما ،نشسسن (ً،مبج ت،ن ف،ع ) مؤتم ( ر ًى فل قت ج ن تا ت تشعان ج ننسجاا ،س ،ننأل،نألمن ن ً، اه ،تنً ،عج ا ش،ث ،تشراخ ن الفان ) .]13 [ناابج الفان ن منذساس  :)ثالثًا/ وكالة غوث وتشغيل الالجئين )األونروا ن لللً ،ن مجالللا ،عذلللس ن ت االللً ت لللًا تنملللخ نللل صلللا ،مؤىتلللا،عج لللا ممصت الللا 1(unrwa)،سللل ،ن( )نأل ًنملخ رنذلسان ،مج ل لج الث ن لً،خ ن ن بالا ن مللج، و منا،ن لل رنذلساسا مذللنان لًا ج رلا 9,1 ،ن ا ن ، بسلجن ،ذل، ) ًت ج(ه انألً هن منذلساساا راللجً لخ لجًخ ن ضلاا لان، ات لج علخ ثلاث ذلس،نئ ً ن ،عج لاتلل ،تمتص بج نرا ن را ن ش نألًس ن منذساساا ،عج ا نألم ن مت ًو إلشجثا ،تشراخ ن الفانب افا نألم ن مت ًو اث ذماتئ ى ن ن لمناا ن نجما بم،لس 2494ت ذذئ ج س ،ن(، )نأل -2 (united nations relief and works agency for palestine refugees in the near eastاختصاراً لـ ) (unrwa)ن سلناقاا ر 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 نألمل اافلا من ملاخ ن تب لجئ ن س، الا ن تلا ت لًم ج ن لً،خ نأل ضلجء رلا مس ملا بج عجمخ ت ابجع ج،ات تم،ان .]19 [ن مت ًو  :رابعًا/ المخّيم و من ن أل ضه اث مصت نمنذساساان ن ان ت تش اًا من ا، تلمت ذعتجسا فىا ن مذج ا م ًً، ن ، بسللجن ف ضلل ،ىلل نا ه ر للً فىامللئ للًو مماتمللجئ رللا ن للًنمخ )ن ضللما ن ر باللا ،ىسللجي شللقو( ،ن مللج ع )نألً ،ذ، اج(ه ،انً )ن ممات (ال، ن تنبال نألعبل ،نألمسل ن ل سلت ملن تل ثا ن لتاخ نإلذل نفانا منذلسان ،ال، .]1 [ ا ال ن منذساسا من ،ل ا س ،ىاا ن معجن شا ن ش مخّيمات الالجئين الفلسطينية: .2 نشأة وتاريخ مخّيمات الالجئين الفلسطينية: 2.2 رللا تللًما ن عاللجن ن منذللساسا ن لل عللجن مجضللنجع رللا للك ن للان استللًنس 2491 للً تذللببئ لل س للج %( من ف ض رنذسان ن تج امالاه 11 س ن ن لقء نألعب )ن ب اسجساه ر ً فىامئ ً، ا رذ نفاخ بنً ا ج ن ،مض مج تب ا من ن ،سن ن منذلساسا نذلاس و ن ن بالاه نمتمل نذل رنذلسان ملن ن مج سلا ن ذاجذلاا نمسس لا ه ، ل مصلسن جن لًالًنن رلا ن لجم، ن منذلساسا ،املج مصلسنح 2491را ف،خ ذلستان بنلً اقاملا لج سللل نك بللللجأل نضا ن منذلللساساا ن مجضلللنا إلشللل نف نإلًن و ن مصللل ااه ،مصلللسنح )ىسلللجي شلللقو( ،اللل، ملللج للل ف آ سالا ن جشلماا ر ل )ن ضما ن ر باا( ،ا، مج ف آس نك بجأل نضا ن منذساساا ن تا ضلمئ إلًن و ن ممنعلا نألً .2411فن ىجمئ رذ نفاخ بج تاخ اجتان ن مسس تان را ف جس س ج ً فذم ئ ن س ن تًما بساا ن ملتم ن منذلساسا ،تشلتائ ن ذلعجن ،ت ل،ان ،من ن سج اا ن ًامر نراا ر ر لل تلمتنلللجئ مللن ن الفلللان ت بلل راملللج تب لل ملللن رنذسان)ن ضللما ن ر بالللاه ،ىسللجي شلللقو( ،رللا ن لللً،خ ن ن بالللا ن ماتمللجئ ذل، اج(ه ،مللن ملاخ الل ج ن تلمتنلجئ ن مشللتتتا عجسلئ ن نبسللا نأل، ل سشلل و م – بسللجن –ن مللج، و )نألً ه اللث رلا ضل،ن ا ن ملًن ،ع س لج للقء مس لج فىاملئ من م لجن الفلان ن منذلساساا رلا ن لًنمخ ،ن شلتجئ ،ن تلا للل ملللن صلللم،ف ملللن ن مالللج رلللا ن بًنالللا سللئ تع،ت نذلللتناض س لللج بنلللً لللك ه ثللل ا بلجسللس بنضللل ج ن لللبنضمت نصت (.1نس شعخ)2من ن ذمسئ ،ف ،نح ن قاسع، اب، ًنئ ذعسا جئين الفلسطينية في الداخل والشتات: مخّيمات الال 2.2 ه ،ىلً ن الفلان ن منذلساساا ملجئممات نذل نلجئ بًنفالا فسنل نا لجت تلمال ن الفلان ن منذلساساان رلا تلمت تمثتنلئ رلا ًنملخ رنذلسان ،سل ،ن ن ممل تستش را مسلجس منالجئ نأل ممامجع 14 ن مجئن ممات تنك ئ ،قت ن تا تبس ن لخ ترساا نألذ ف. با،ئفذسح ن ر، ت،ض صمجفح منًساا ماصا ن ثمنه اا بج و ن ن قاسع، ف ،نح -2 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 ن ، بسللجن ،ذلل، اج()ن ضللما ن ر باللا ،ىسللجي شللقو( ، نس لل -]21 [ ن شللتجئ اللث ن للً،خ ن ن باللا ن ملللج، و )نألً (.3( شعخ)2لً،خ) مخّيمات الالجئين الفلسطينية في قطاع غزة: 2.2 ن ل ان ت،قت ل،ن رلا ممتنلف ملًن ،ىل ى ن سلجيه الث ننذت بخ ىسجي شقو للقءنع عبال نع ملن ن الفلان ن منذلساساا ف ، للًى نألىللج س ،رللا ثعسللجئ ذللجب ا نلللاف ن ب اسللجسا رضللاع للن نأل ض ن مضللجء ت،قت لل،ن رللا ن مذللجلً ،ن عسللج نل رسشلجء ن مماتملجئ ن منذلساساا ًنملخ ن سلجي ،ن تلا تمثتنلئ ]13 [3)ن ن نء( ر فن منئ لمناا )ن ع،اع ق( مللجنه ن للبنح ًالل هن بلل ا ه ن مرللجق ه ن سصللا نئه ن شللجس ه )لبج اللج: للا نلل ن س لل، ن تللج امللجئ م،قت ممات (1رللا) (.9( شعخ)1نس لً،خ) -( رح ها،س بعض الخصائص الديموغرافية والسّكانية لمخّيمات الالجئين الفلسطينية في قطاع غزة: 4.2 ن تبجاسلللللجئ رلللللا من للللل ن مصلللللجف ن ًام،ش نرالللللا ذلللللعجن ن مماتملللللجئ تمتنلللللف عثاللللل نع لللللن ن مصلللللجف ،انلً، ن ذلبس رلا للك ر ل فن ن شلنس ن منذلساسا اتمالق بسذللا ن ًام،ش نرالا ذلعجن ن ملًن ًنملخ ىسللجي شلقوه نلتمج ا ،ن ًه رضلاع لن لك رلان ن نًالً ملن ن الفلان ىلً ت عل،ن ن مماتملجئ ،ذلعس،ن رلا ن مسلجس ن ضل اا ،ن اماا. ه الث تسج، لئ تنلك ]21 [1004( نلج ،سل ،ننأل،رلا آمل ً نذلا فل ت لج ،عج لا شل،ث ،تشلراخ ن الفلان ) نذللللا بنللللض ن مصللللجف نمبللللجسا ن ذللللعساا ،ن ،ضلللل ن لتمللللج ا ،ن ىتصللللجً ،ن بساللللا ن ت تاللللا نمماتمللللجئ ن ً ن منذساساا را ىسجي شقو ، ك ن ن س ، نآلتا:  :(1،1نس شعخ) -أواًل/ المباني السكنية داخل المخّيمات.  :(1،1،4نس شعخ) -ثانيا/ الوضع االجتماعي واالقتصادي داخل المخّيمات  :ثالثًا / البنية التحتية  ن ص ف ن ص ا: تت،ر شبعجئ ن ص ف را من ن مماتمجئ ن منذساساا ب سجي شقو مج ًن ممات مجن ا،س .  ماجج نألمسج: من ن مماتمجئ تمت شبعجئ تص اف ماجج نألمسج ه الث انلجسا ذلعجن ن مماتملجئ ملن مشلعائ ًمل،خ بجسا ن ذعساا.ماجج نألمسج را رصخ ن شتجء ًنمخ ن م 3 ب سجم ن شبجس -انألصًىجء نألم اعا،اا لمناا اافا مًمجئ 2441ت ذا ر ي ج ج ،را رنذسان 2421نألم اعاا ج ن مت ًو ن ، اجئ ( ت ذذئ راquakersع،اع ق ) american friends service committee: ا،ت لمت ج بج سلناقا -ن منذساسا 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11  مجئ ن صنبان ممنت: ت ل، نأل،سلل ،ن بج نمللخ رللا لمالل ن مماتملجئ مللن ن للتمنت مللن ن ممنتمللجئ ن صلنبا مللج للًن مماتمللا رللح ،مللجن ا،س . المشكالت العامة لمخّيمات الالجئين الفلسطينية في قطاع غزة: 2.2 ا ا لل ذللعجن ن مماتمللجئ ب ىللخ , ،بج تللج4 شللم لن ً،س 77.13تبنللا ن عثجرللا ن ذللعجساا نملل، ن ممامللجئ (2 .]29 [سصاس من ن ذتمًن بشعخ ج رلللان من للل مماتملللجئ ىسلللجي شلللقو تنلللجسا ملللن ن تضلللمت ن جفلللخ رلللا لللًً راملللج اتننللل بلللج ،ف ن مناشلللاا (1 ف لف شلم الث ن ذلعجن اتم علق،ن رلا 201ن ذعجنه رنن ذباخ ن مثجخ ممات لبج اج ن ا ج س من ك فن من نألذ قن ئ تناف را با،ئ صرا و مع،تسا را ن رج س ً،س ه فضف ر 2991مذج ا من ش را ف، ش رتانه رضاع ن فس ج ت،ر ن مجاا ن عجراا ذ،نء من ل ن صلاف ف، بلً ن شلتجء مملج اقاً من ممجس نألم نض. تقنالً ن مذلتم نلًً ران ن مًن تنجسا من نعت لج ،نضلح نتامال مل ن رامج اتنن بج ،ف ن تنناماا (3 ن ذعجن ،ىنلا ن مذلج ا مملج اسلت س لج مشلعنا ،الا س لخ ن تامال ر ل ملًن ملج ع لًً، ن مملات ه نألمل ضج ا ن ،ىئ. ن اًؤ ر بنً ن مذجرا ،صن،با ن ست جخ ،ن نً رامللج اتننلل بللج ،ف ن صلل اا (9 لجسللس ر لل جساا ن متقناللًو ستالللا ن عثجرللا ن ذللعت نأل،ضللجي ذلل،ءنع اللث تللًق نألقىلللللاتلللللً ن ،ضللللل ن صللللل ا الللللث ،مملللللج اقالللللًملللللا ملللللن ن ل لللللجئ ن ذلللللمااه تسللللجى ن ملللللًمجئ ن م ًت نألملل نضمللج اذللبس نستشللج م نألسمللجخانبللث ب للج ،ن تللا ،ن ماللجج ن نجًمللا ن تللا تملل بللان ن س ىللجئ ان ضللات (. 20نس شعخ) -جن ن س ا ن ممج سان تا تست خ بان ن ذعت ،نأل،بفا الللث ا،للللً ن تملللجي منلللًت ئ ن بسج لللا ، لللك ستاللللا تلللًا، ن للل ،ف ،ف ن ىتصلللجًااراملللج اتننللل بلللج (1 ن ىتصلللجًاا ،نإلشلللا ن مذلللتم نمنلللجب ملللن ىبلللخ ن لجسلللس نإلذللل نفاناه الللث من للل ن للل،ى ن نجمنلللا رلللا ن مماتمجئ تنتمً بشعخ عبا ن ن نجفً ن مجً من ن نمخ ًنمخ رذ نفاخ. اث ا،للً تلًا، ،نضلح رلا من ل ن مماتملجئ لمال شلبعجئ ن بسالا ن ت تالا رامج اتنن بج بساا ن ت تاا (1 . ]12 [،ن متمثتنا را: )ن س ه ن ماججه ن ع بجءه ن ص ف ن ص اهن ممنتمجئ( -: -حالة دراسية -. مخّيم خان يونس لالجئين2 مضلنئ ن مًاسلا عرا الج ر ًى مًن رنذسان ن تج اماا, ،ثجسا مًاسا را ىسجي شقو, ، ً مًاسا مجن ا،س , 2121 , ر لً عم لج ن ممج الك تل لج 2311من ن مًن ن منذساساا ع عثا من ن ً،خ مس رسشجف ج ج -2421 , ثللل ب اسجسالللج رلللا ن بلللا بلللان لللج 2421 -2121ثللل نألتللل نك ن نثملللجسا،ن رلللا ن بلللا بلللان لللج ب ل،ن ا 1001( اث ت ت ذا رلمج ا ًً ن ذعجن ًنمخ ن مماتمجئ ،ن تلا ت لً ذلس فمل ر صلجفاا نلج 1بج ل،ي ر لً،خ ى ) نم، ن ممامجئ ن عثجرا ن ذعجساات ذجس مت،ذس -4 ً،س .( 6238ن مذج ا نإللمج اا نمماتمجئ ،ن تا ت ً ب ،ن ا ) ن ( شم 481180) 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 , ،ن تلا علجن رلا ،ىت لج ]1 [ 2411 2491 ملج بلانن بلا سجي شقو رلا اامص ن ،صجاا , ث ن 2491 مناا ت لا ن الفان ،سش و ن مماتمجئ ،مس ج ممات مجن ا،س م،ض ن ً نذا . نبذة عن مخّيم خان يونس لالجئين: 2.2 ذعتجسم مجئ الفان را ىسجي شقو ،من ثمجساا ممات ا، ،ن ً من، 2494 ج ا،س مجنممات فسش بن،ك ن بنض مس ج را مسجس مسممضا 23 ر ،اس ذ ن ممات ه مسس ا بف ن ذب من ون م لت ن ىمن ، ا،لً س ج هنألذمستا ن مرس بجألذبذئ من ن س،س ن مبجسا ن ذعساا،من هارسا ج ن ماضجن شتجءنع ت،ر نأل،س ،ن مجع بج ماجج من آبج ماجج ن بنًاا ،ن مجصا. ن مبجسا ن ذعساا،تقً، لما ه ص ف ص ا بج ممات ً ن مشج ا رضاع نرًن و ن سمجاجئ ن صنباه ،ن مًمجئ ن ص اا ،ب سجم ن تننا نألذجذارا ن ممات .ن تلج اا ن صرا و ،نضح اث ن ىتصجً ا، ه ،ن تًت جمجع 18 ٪ من ن ذعجن ً،ن11من ن شبجس اث من ذعجن ن مما .]21 [من ملم،ي ن نجمنان ٪13ن تا تتلج،ق ن بسج ا تمجي منًخ ٪ ستالا11,1 ر منًخ ن م اصخ وقد تم اختيار مخّيم خان يونس كحالة دراسية لتطوير مخّيمات الالجئين في قطاع غزة لألسباب اآلتية: ن م ن مًى نذعجن ،تًا، نأل ،نخ ن مناشاا نممات بشعخ ،نضح. (2 ن تت،ر م ن بساا ن ت تاا نص ف ن ص ا. ممات مجن ا،س اعجً اع،ن ن ممات ن ، اً (1 سً و ن م نر ن نجما ،ن ت را اا ،ن مذج جئ ن مض نء را ن ممات . (3 ممات مجن ا،س ا تخ ن لجسس ن ر با مًاسا مجن ا،س ،بج تج ا امس س ج ن متًنً ن سبانا نتلجج (9 سبانا ن ممسس ن اعنا عجن بً من ن ر س ، ت اع،ن ت،ذ ن مًاسا س ، ن ر س ش،نفاجع ،اض ب ر جًو ت ااخ ن ممات م ،ض نذت نتالاجئ جما تس،ا ج من ماخ ر جًو ت ااخ ن مبجسا ن ذعساا تنبا و ت ذان رضاع ن ،ت عاس شبعجئ ن ماجج جئقاجًو ن مذج جئ ن مض نء ،ت،ذا ن س ىمنجاا ن لً، .،منج لا ن سمجاجئ ،ن ص ف ن ص ا ت المتعّلقة بمخّيم خان يونس لالجئين:الدراسا 2.2 ملن ملاخ ن ت عالق -مملات ملجن ال،س الفلان ً ىلج ن ب لث با لًنً ن ً نذلجئ ن متننت لا بج ج لا ن ً نذلاا (.3نس لً،خ) ن ن م ج، ن فاذاا نآلتاا: 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 -التخطيط والتصميم المعماري للمخّيم: 2.2.2  أواًل/ موقع المخّيم ومساحته: مًاسان مت،ذس را ن لقء ن ر با من نألباضن ب ن بنً ،ن ا عان،مت ان من ذج خن ممات ا 2111ا مذج ن رنذساسا ل 11212،اناف را ن مما ،ن ا -(22ه نس شعخ)ا،س مجن .5 شم ل ن ً،س 50.67 اث تبنا ن عثجرا ن ذعجساا ًنمخ ن مما ه]21 [ً،س  ًاستعماالت األراضي في المخّيم:ثانيا / % مسجس مض نءه باسمج 9,4% س ه 11,1% من نذتنمج ئ نأل نضا را ن ممات مبجسا ذعسااه 91,4 (.21( ،شعخ)9نس لً،خ) -% مًمجئ جما10,1  /في المخّيم: مساحة المباني القائمة وعدد الطوابقثالثًا ا مبلجسا تتل ن،ح مذلج ن ال ج % ملن33مبسل ه الث 9043 ،ن ا ات ن،ح ًً ن مبجسا ن جفما ًنمخ ن ممات -( متل م بل 10-200) ا م،نىن لج% من ن مبجسا تت ن،ح مذلج 31( مت م ب ه انا ج 202-210) م،نىن ج .(1نس لً،خ) % من مبجسا ن ممات اا بج و ن سجب ف ضا11 (.1نس لً،خ) 6  /في المخّيم: ية التغطية للمباني القائمةنوعرابعًا الللا ملللن % 21,1ملللن ن م ذلللجساه باسملللج % 30,9ملللن ترسالللا مبلللجسا ن مملللات الللا ملللن نإلذبذلللئه 13,1% . (29)( ،شعخ1نس لً،خ) -نإلذبذئ ،ن م ذجسا  : خامسًا/ جودة المباني القائمة في المخّيم -% لاللًو( 21,4م ب، للاه باسمللج % 31,2ملن مبللجسا ن ممللات نئ رنج اللا ضللناما اذللتمًن ن ذللعساه 91% (.21( ،شعخ)1نس لً،خ) البنية التحتية للمخّيم: 2.2.2  :أواًل/ الطرق شج باا ن س ًنمخ ن ممات شا منبًو ،اا بج و ن فقىا ضات ا ن مذج ا ،شا متذنا.  :ثانيَا/ شبكات المياه ت نئ را جه ن ا ، من ذلعجن ن مملات بشل نء ماجج ن بنًاا اا ماجج شا صج ا ن ش س تمجي سذبا ن س ن ماجج ن م اتو اذتنمجخ. ( 62181ب ل،ن ا ) 1001،ن تلا ت لً ذلس فمل ر صلجفاا نلج ذلعجن ًنملخ ن مملات ن اث ت ت ذا لًً (ه 1ًنمخ ن ممات بج ل،ي ر لً،خ ى ) ن عثجرا ن ذعجساا س مت،ذس ذجت 5 ً،س . (1227،ن تا ت ً ب ،ن ا ) ن مذج ا نإللمج اا نممات ن شم .رنذسانا،س ه مجن 1020-9-20بتج اخ –مجن ا،س بنًاا بىذ ن تمساس ،ن تس ا ن ض فا جت فب، ن ساف م " م جبنا شمصاا " -6 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 30  :ثالثًا/ شبكة الكهرباء ت تبس شبعا ن ع بجء نممات بشبعا ن ع بجء ن نجما مًاسا مجن ا،س . % من ذعجن ن ممات انتمً،ن ن ن ع بجء ، ا ،م،ن بًر ذ، ن شت نك.40 ع بجفا ،نضح بذبس ن ت ماخ ن قنفً ن شبعا ن ع بجء.نذتم ن نس سجي ن تاج ن  :رابعًا/ مياه األمطار % مللن شللبعا ن ممللات تتصللخ بمس ،مللا تصلل اف ماللجج نألمسللج ه ،مللن فالل ن مشللعائ الل، تنلل،ث ماللجج 10 نألمسج بماجج ن ص ف ن ص ا ،ع ك ًم،خ ماجج نألمسج را ن مسجقخ.  :خامسًا/ المخّلفات الصلبة بتلمالل ن ممنتملللجئ ن صللنبا ،تنملللخ نللل ن مللج نللل ن س جرللا ،اسلللجك متجبنللا مذلللتم و للل ج سللل ،ن، نألت للت ن م ما ن فذج فسم ن تقن تلجج ن الفان ن م لت ان من م،سس نألصنا. الدراسات السكانية واالجتماعية للمخّيم: 2.2.2  :)أواًل/ السكان )البنية المجتمعية %ه ث تنا ج رفلا 31,1جبجع اث تمثخ ف ن سذبا من ن ذعجن من ن سنبا ،ن تاما انً ن ممات ملتمنجع ش ( .4نس لً،خ) -% ,,13ن نجسنان ن ن نمخ ،ن تا ت ً بسذبا  :ثانيًا/ آراء السكان في المغادرة أو البقاء في المخّيم ذللت نء آ نء 1004( نللج ،سلل ،ننأل) نبسللجءنع نلل ن ً نذللا ن تللا ىجمللئ ب للج ،عج للا شلل،ث ،تشللراخ ن الفللا تلل ت،قان للج بس ا للا شلل،نفاا تمثنللئ رللا ئذللعجن ن ممللات لل،خ ن مرللجً و ف، ن ب للجء راللم ، للك مللن مللاخ نذللتباجسج (ه الث شل اس ح نألذفنا نآلتاا :)منعاا نأل ض را ن ممات ه مرجً و ن ممات ه ر لجًو ت االخ ن مملات ه ن نلاف رلا % من منعاجئ نأل نضا را ن ممات اا منعاجئ ع،مااه 11ا نإللجبجئ نآلتاا: )اا من ماخ تنك نألذفن لللن،ن مرلللجً و ن مملللات ه 11 لللن،ن ر لللجًو ت االللخ ن مملللات ه 10% ملللن ن ذلللعجن امضت % ملللن 11% ملللن ن ذلللعجن امضت (.21،21،21،24نس نألشعجخ ) -ن ذعجن امضتن،ن ن ناف را ش ا (10شعخ)نس -:المشكالت العامة للمخّيم 2.2 ن تعًت ن ذعجسا ن ،نضح ًنمخ ن ممات . (2 ذ،ء ن تشساس ن منمج نمبجسا ن جفما ،ضنف رنج ات ج اذتمًن ن ذعسا. (1 سً و ،لً، ن م نر ن نجما ،ن مسجس ن ت را اا ،ن مذج جئ ن مض نء ًنمخ ن ممات . (3 ذ،ء ن بساا ن ت تاا بعجرا فس،ن ج. (9 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 32 . النتائج والتوصيات:4 تائج:الن 2.4 تنللجسا مماتمللجئ ن الفللان ن منذللساساا رللا ىسللجي شللقو مللن مشللعائ جمللا ،،نضلل ا ،مشللت عا نلل مذللت،ى ممات مجن ا،س الفلان نأل،ضجي ن مناشاا ،ن ىتصجًاا ،ن لتمج اا ،ن تنناماا ،ن مًمجتااه فمج رامج اتنن ب جئ ىسللجي شللقو ستالللا ت،نلللًج رللا ف للً ،الل، م،ضلل،ي ن ً نذللا ر لل، انللً مللن ف للً ن مماتمللجئ ن جمللا مللن ممتاملل ن م نعق نإلىناماا ن م ت لا ضلمن ن ممسلس نإلىناملا سلجي شلقو ،الا مًاسلا ملجن ال،س ه ،ال، ملن ن مماتملجئ ن لل ملل بعثالل مللن ن لل ،ف رللا للخ ت،نلللًج مللن تللًما نمبللجساه عمللج ،انللجسا ن ممللات ن نًاللً مللن ن مشللعائ لج ملج ال، ملج بلج ممات سمذلمه ،ىلً تل ن تذلناس ن ضل،ء نل شج بالا مس ج مج اسسب ن عجرا ن مماتمجئ ،مس ومن ثمم فمان الباحمث يوصمي باالسمتراتيجيات اآلتيمة نأل،ضجي ن ًام،ش نراا ،ن مشعائ ن تا ا،نل ج ن مملات . .ومخّيم خان يونس بشكل خاص لتطوير مخّيمات الالجئين الفلسطينية بشكل عام التوصيات: 2.4  متعّلقة باستراتيجيات تطوير مخّيمات الالجئين الفلسطينية بشكل عام: أواًل/ توصيات ن مذللح ن ماللًنسا ، صلل ن م،نىلل لمالل ن مماتمللجئ ، للك مللن مللاخ:) ن مذللح ن ذللعجساه ن مبللجسا ن ذللعساا (2 ،ن نجماه ن بساا ن ت تاا(ه ، ك ت ًاث ى،ن ً ن باجسجئ بشعخ مذتم م ف مشلعنا ،،ضل لً لج ىبلخ ج.تمجىم ن ت،نصخ ،ن تسذا ن ملتمنا ن مذتم من ماخ ، ف ن نمخ ،ن لنذجئ م عخ نألس نف ن منساا بتسل،ا (1 ن مماتملللللجئ ،ن متمثتنلللللا را:)فالللللج ا ن مماتملللللجئه ن بنلللللًاجئه ن مؤذذلللللجئ ن ،سسالللللا ،نألانالللللا(ه ، لللللك م للللل ن تاجلجئ ،ن م ت جئ ،ن م ،ع بستجف م ضاا عجرا نألس نف. مشلل ، جئ ن تس،ا اللا نمماتمللجئ مللن مللاخ ً نذللا ،ت ناللخ ،ن للً ن باجسللجئ ن مجصللا بعللخ ن ذللنا ت للًا ن (3 ممات ،ر ،ت ناخ ،نى عخ ممات ،ن ذتنجسا بج ذتشج اان ، ، ن مب نئ. ت،را ر ن نمخ ن مسجذبا من ماخ ن مشج ا ن تسم،اا ن شجبا. (9 ج را لما ن مماتمجئ.تس،ا ،ت ذان لما شبعجئ ن بساا ن ت تاا بعجرا فس،ن (1 ،ض مسس رذت نتالاا مذت بناا آل اجئ تذعان نألذ ن مذت بانا ن مجصا بج شبجس ن ان اشلعتن،ن ن سذلبا (1 ن نج اا من ذعجن ن مماتمجئ را ج ا تع،اس ألذ ،ن ق،نع.  :ثانيًا/ توصيات متعّلقة باستراتيجيات تطوير مخّيم خان يونس بشكل خاص اجئ ن تاجلجئ را ن ممات را رسج مناا ن تس،ا .،ض ى،نف ب ، ، (2 ،ت عالس جئ،قالجًو ن مذلج جئ ن مضل نء ،ت،ذلا ن س ىل ت ذلان ن مبلجساملن ملاخ منمج الجع ن مملات تس،ا (1 .،منج لا ن سمجاجئ شبعجئ ن ماجج ،ن ص ف ن ص ا و. (3 ر جًو ت ااخ ن مبجسا ن ذعساا ن تا تنبا منجاا ن لً، 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 31 نمذج ًو را قاجًو ًمخ نألذ و. ، ك ن م فو فن تذجا ب جتا امعن ن مشج ا ن س ح (9 تصما مشج ا نإلذعجن ن لًاًو بج س من ن ممات ب اث تع،ن متصنا منم ، اشن ن ذجعن ببنًج ن (1 وه ،بج تج ا ران مناا نإل اخ تذجا را تم اا مذج ا من ن ممات نألم ن ن ممات ، ام ًج ن نً، نسا ر صا فعب نمناجئ نإلصاح ،ن تس،ا .ا ن ذتمجًو من مقناج ،مب نئ ن مشج ا ن ممجثنا ن تا ذب تسما اج را تس،ا ن مماتمجئ ن منذلساساا نألمل ى (1 مثخ ممات ن شجس بمًاسا شقو. .ن ممات ًنمخن تمساس نتسماا ن مذتًنما ن نمخ ن ،ض تص،ت نمناا (1 نئ ن ذلللعجن ،ن تنلللج،ن ن مذلللتم بلللان عجرلللا ت اللل مبلللًف ن شللل نعا ن شللل (1 نباا ،ن تملللجً نللل ىلللً نئ ،مل لللً، ن ل جئ ن مذؤ، ا ن ن ممات . المراجع / " ذج ا مجلذتا شا مسش، وه إسكان المخّيمات في قطاع غزة( " 1991فب، ذم وه ف مً مناخ م مً ) (1 لم ، اا مص ن ن باا. –لجمنا نألقا بج جا و " ، ىا ب ثااه ،عج ا ن ر،ث )نأل،س ،ن(ه شقو رنذسان. تطوير مخّيمات الالجئين( " 1220بً، ه فذجما ) (1 " م فا ن ذ جت فب، مقابلة شخصية( " 1212بنًاا مجسا،س ه ىذ ن تمساس ،ن تس ا ن ض ) (3 رنذسان . -ن ساف ه مجن ا،س " ذلج ا للمخّيممات الفلسمطينية الخصائص العمرانية والتخطيطيمة( " 1222تصن ه فمخ صاح م ملً ) (, رنذسان. –مجلذتا شا مسش، و ه لجمنا ن سلجحه ن ضما ن ر باا -7491مشمممكلة الالجئمممين الفلسمممطينيين ، نشمممو ها وتطّورهممما ( " 1222لللل نًوه م ملللً للللس ىلللً، و ) (5 " ذج ا ًعت، نجه لجمنا صسنجء بلم ، اا ن امن . 7491 " األونروا ومالءمتها للبيئمة الطبيعيمة والعمرانيمة فمي قطماع غمزةمشاريع إسكان ( " 1212ن م نه رل،ق ) (2 ذج ا مجلذتا ه ىذ ن سًذا ن منمج ااه عناا ن سًذا ن لجمنا نإلذامااه شقو. " ذلج ا تأثير االحتالل اإلسرائيلي على العمارة والعمران في قطاع غزة( " 1222ن م نه مصسما عجملخ ) (2 اف بج جا وه لم ، اا مص ن ن باا.ًعت، نجه لجمنا نألقا ن ش " ًن ن ع ملخ نسشل ،ن ت،قال ه ن سبنلا خان يونس ماضميها وحاضمرها( " 1990ن م نه م مً ن م ) (0 ن. نأل، ه مجنه نألً ن . موسوعة المخّيمات الفلسطينية( " 1992ىًذااه باس بً ن ذا ) (9 " ن لقء نأل،خ, مجنه نألً لم ، الللا مصللل –" ن افلللا ن نجملللا نعتلللجسه ن لللجا و غمممزة وقطاعهممما( " 1902ن مبللاضه ذلللنا رلللجئ ) (12 ن ن باا. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 33 -مخّيمات الالجئين الفلسطينيين بين الواقع وطموحات المستقبل( " 1212م ذنه بً ن ع ا ذلن ) (11 " ، ىلا ملخ مسشل، و رلا ملؤتم تذلاا ن ملًن بلجمنلا ن مذلانا حالة دراسية مخميم الشماطب بمدينمة غمزة نف .بج لق المخطمط اإلقليممي للمحافتمات ( " 1222،قن و ن تمساس ،ن تنج،ن ن لً، ا ) -ن ذنسا ن ،سساا ن منذساساا (11 " م جر جئ شقوه رنذسان. (5050-5002الجنوبية ) نتمممم المعلوممممات الجغرافيمممة والتخطممميط ( " 1222،قن و ن عللل ن م نلللا ) -ن ذلللنسا ن ،سسالللا ن منذلللساساا (13 نذسان ." م جر جئ شقو ه ر الحضري خصمائص السمكان فمي المخّيممات ( " 1220م علق نإل صلجء ن منذلساسا ) -ن ذنسا ن ،سساا ن منذساساا (,1 " شقو رنذسان.الفلسطينية الالجئمون الفلسمطينيون ( ً نذلا بنسل،نن " 1220ًنف و شف،ن ن ممج،ضجئ ) –مس ما ن ت ا ن منذساساا (15 " شقو رنذسان. 5002 األوضمماع الديموغرافيممة لالجئممين ( ً نذللا بنسلل،نن " 1222 ن الفللان )ن افللا ن منذللساساا مجاللا لل، (12 " شقو رنذسان. م5009وحتى العام 7492الفلسطينيين في قطاع غزة من عام السياسمممات واالتجاهمممات لوضمممع ( ً نذلللا بنسللل،نن " 1229،عج لللا شللل،ث ،تشلللراخ ن الفلللان )نأل،سللل ،ن( ) (12 . " شقو رنذسان مخّيمات الالجئين في قطاع غزة " شلللقو ملمممف مخيممممات الالجئمممين( ً نذلللا بنسللل،نن " 1225،عج لللا شللل،ث ،تشلللراخ ن الفلللان )نأل،سللل ،ن( ) (10 رنذسان 19) gharbawy, abdelkarim 2000 " the palestinian refugees housing status case study: (beach refugee camp) " -master thesis (architecture department) – ankara. 20) jouda, abdelkarim 2008 " improving quality of life in khan younis refugee camp evaluation & future outlook ". 21) unrwa 2005 " restructuring beach camp, sehp – project design unit" . 22) unrwa.1999, unrwa in figures, united nations relief and works agenc for palestinian refugees in the near east, public information office, unrwa h.q., gaza. المواقع االلكترونية: 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 39 13) http://www.un.org/unrwa/arabic 1213-3-12ت ن قاج و بتج اخ -تن اف ،عج ا ن ر،ث. 1,) http://www. palestinehistory.com 5-15 تل ن قالج و بتلج اخ -تلج اخ ن مماملجئ ن منذلساساا1213. 15) http://ar.wikipedia.org 10تلللل ن قاللللج و بتللللج اخ -مللللس ن م لللل ،اعاباللللًاجه ن م،ذلللل، ا ن لللل و-,121,. 12) https://www.afsc.org/sites 121-,-10ت ن قاج و بتج اخ -مؤذذا مًمجئ ع،اع ق,. 12) akhbar.com/node-https://www.al ،121-,-19ت ن قاج و بتج اخ -تن اف ف ،نح ن قاسع,. 10) http://ejabat.google.com/ejabat 121-,-19اج و بتج اخ ت ن ق -فس،ني نألذ ن منذساساا,. 19) http://www.s1sh.com 121-,-19ت ن قاج و بتج اخ -تن اف ن ً،س,. ف ًنً ،سذس ن مماتمجئ ن منذساساا من نإللمج ا را عخ مسس ا )ن ًنمخ ،ن شتجئ( ا،ضتح(: 2لً،خ ) ةالنسبة المئوي عدد المخّيمات المنطقة % 29 1 ىسجي شقو % 31 24 ن ضما ن ر باا ن % 21 20 نألً % 10 21 بسجن % 21 20 ذ، اج % 200 25 المجموع (: ا،ضتح 3شعخ) سذس ت،قا ن مماتمجئ ن منذساساا را ن ًنمخ ،ن شتجئ لبنان 17% سوريا 20% االردن 17% الضفة الغربية 32% قطاع غزة 14% قطاع غزة ضفة الغربية ال االردن سوريا لبنان )تس ا ن بج ث( (1001)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً http://www.un.org/unrwa/arabic http://www.un.org/unrwa/arabic http://www./ http://www./ http://ar.wikipedia.org/ http://ar.wikipedia.org/ https://www.afsc.org/sites https://www.afsc.org/sites https://www.al-akhbar.com/node https://www.al-akhbar.com/node http://ejabat.google.com/ejabat/thread http://ejabat.google.com/ejabat/thread http://www.s1sh.com/ http://www.s1sh.com/ 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 31 ذس عخ مسس ا من ن سجي 1001ر صجفاجئ مماتمجئ ن الفان را ىسجي شقو نج ا،ضتح(: 1لً،خ ) المنطقة اسم المخيم سنة اإلنشاء المساحة 7)دونم( 2008لعام الالجئين السكان عدد خارج المخيم داخل المخيم 83114 107378 1448 1954 لبج اج جباليا 221004 80915 900 1951 ن شجس غزة 58974 588 1948 ن سصا نئ الوسطى 33528 30055 478 1952 ن ب ا 20372 150 1949 ًا ن بنح دير البلح 23416 547 1949 ن مرجق 43411 114674 62181 1227 1948 ا،س مجن يونس خان 71214 97889 900 1949 رح رفح 566945 481180 6238 اإلجمالي 1048125 في قطاع غزة الالجئين جمالي عدد السكانإ (1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً -ممات مجسا،س الفان -ن م ج، ن فاذاا نً نذجئ ن متننت ا بج ج ا ن ً نذاا ا،ضتح(: 3لً،خ) الجتماعيةالدراسات السكانية وا البنية التحتية التخطيط والتصميم المعماري م،ى ن ممات ،مذج تم. نذتنمج ئ نأل نضا. مذج ا ن مبجسا ، ًً ن س،نب . اا ن ترساا نمبجسا ن جفما.س، و ن مبجسا ن جفما. لً، ن س . شبعجئ ن ماجج. شبعا ن ع بجء. ماجج نألمسج . ن ممنتمجئ ن صنبا ن ذعجن )ن بساا ن ملتمناا(. ن ذعجن ،خ ن مرجً و ف، ن ب جء را آ نء ن مما . تس ا ن بج ث –ن مصً نذتنمج ئ نأل نضا را ن ممات ا،ضتح(: 9لً،خ) النسبة المئوية المساحة بالدونم نوع االستعمال % 91,4 100 مبجسا ذعساا % 11,1 323 س % 9,4 10 مسجس مض نء % 10,1 119 مًمجئ جما % 200 2227 مالياإلج سذس نذتنمج ئ نأل نضا را ن ممات (: ا،ضتح21شعخ) مباني سكنية 48.9% طرق 25.5% مناطق خضراء 4.9% خدمات عامة 20.7% مباني سكنية طرق مناطق خضراء خدمات عامة ( )تس ا ن بج ث(1020مجسا،س ه ىذ ن تمساس ،ن تس ا ن ض )بنًاا -ن مصً 7 تذتنمخ ا ج ن ، ًو ت ن ا، را ن ً،خ ن تا عجسئ تجبنا هأل،خ م و ،ب ائ ن ا ن ن جخ ت ا،مسج ا ن ، ًو ىاج مذج ا نأل ضه نذتنمنئ را نإلمب نس، اا ن نثمجساا :مالدون :، عن مذج ا ا ج ن ، ًو تمتنف من معجن ر آم ه رمثاع ه إلمب نس، اا ن نثمجساا ذجب جع ن مت م ب ىبخ نس اج نألمب نس، اا ن نثمجسااه ،بنً نس اج اج 42413عجن انجًخ ن ً،س مت م ب ه م نت عا فن 2000انجًخ ن ً،س :(را باً ن شج )ذ، اج ،رنذسان ، بسجن ،نألً (.وهذا ما تم استخدامه في هذه الدراسة) مت بًخ من ن م ج نألما 2000ر ن ً،س را ن ستًنس ن ب اسجسا ى تراا .ب مت م 233111ىً م ب ف، 29900انجًخ ن ً،س : را شمجخ ىب .مت م ب 1100انجًخ ن ً،س : را ن ن ن http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 http://www.s1sh.com/vb/showthread.php?t=7417 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 31 نذتنمج ئ نأل نضا نمًمجئ ن نجما ًنمخ ن ممات ا،ضتح(: 1لً،خ) النسبة المئوية المساحة بالدونم نوع االستعمال % 3,4 20 مذجلً % 31,9 40 مًن % 111 12 مسجس اجضاا % 12,1 19 مذتشماجئ % 2,1 3 س،نً % 1,4 21 مبجسا ع،ماا % 1,1 1 مبجسا تلج اا % 1,4 21 مبجسا ،عج ا ن ر،ث % 1,3 1 مؤذذجئ فلسباا % 1,4 21 ًنف فسمجخ % 110 21 فم ى % 200 224 اإلجمالي سذس نذتنمج ئ نأل نضا ،ضتح(: ا23شعخ) نمًمجئ ن نجما ًنمخ ن ممات )ن م،نى ن ممصصا( نوادي 1.2% مدارس 35.4% مناطق رياضية 8.7% مستشفيات 21.2% مباني حكومية 5.9% مباني تجارية 2.6% مباني لوكالة الغوث 5.9% مؤسسات أجنبية 2.3% حدائق أطفال 5.9% أخرى 7.0% مساجد 3.9% مساجد مدارس مناطق رياضية مستشفيات نوادي مباني حكومية مباني تجارية مباني لوكالة الغوث مؤسسات أجنبية حدائق أطفال أخرى ( )تس ا ن بج ث(1020مجن ا،س ه ىذ ن تمساس ،ن تس ا ن ض )بنًاا -ن مصً ممات ن ن مبجسا ن جفما ، ًً ن س،نب را م،نى مذج ا ا،ضتح(: 1لً،خ) (m²)المساحة الطوابق النسبة المئوية عدد المباني 200< 151-200 101-150 50-100 50 > % 76,2 3119 553 643 1008 1020 95 طابق أرضي % 16,0 657 88 113 233 216 7 طابق أول % 5,4 221 50 58 71 42 -طابق ثاني % 2,4 96 22 27 30 17 -طابق ثالث 4093 613 741 1342 1295 102 عدد المباني 100% 14,9% 18,1% 32,8% 31,7% 2,5% سبة المئويةالن )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً را ن ممات اا ن ترساا نمبجسا ن جفماس، ا،ضتح(: 1لً،خ) النسبة المئوية عدد المباني نوع التغطية %13,1 2203 فذبذئ % 30,9 1245 م ذجسا % 21,1 645 فذبذئ+ م ذجسا % 200 4093 اإلجمالي اا ن ترساا نمبجسا ن جفماس، سذس (: ا،ضتح29شعخ) را ن ممات أسبست+ خرسانة 15.8% خرسانة 30.4% أسبست 53.8% أسبست خرسانة أسبست+ خرسانة )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 31 و ن مبجسا ن جفما را ن ممات ا،ضتح(: 1لً،خ) لً، النسبة المئوية دد المبانيع الجودة % 21,4 735 لاًو % 31,2 1440 م ب، ا % 91,0 1918 ضناما % 200 4093 اإلجمالي و ن مبجسا ن جفما را (: ا،ضتح21شعخ) سذس لً، ن ممات مقبولة 35.1% ضعيفة 47.0% جيدة 17.9% جيدة مقبولة ضعيفة )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً ملتمناا نممات ن بساا ن ا،ضتح(: 4لً،خ) النسبة المئوية عدد األشخاص النوع % 24,2 11876 فسمجخ % 31,1 23504 سنبا ،تاما % 3,1 2338 لجمناتان % 1,4 3668 مذساان % 20,1 6342 متجخ % 13,9 14453 جسنان ن ن نمخ % 200 62181 اإلجمالي )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً 2491 ج (: ا،ضتح ال و ،تش اً نآل ف من ن منذساساان ف جس س1شعخ) ص، و ت،ضتح نألسمجخ ًنمخ ن ماج را ن ممامجئ ن منذساساا ص، و ت،ضتح شعخ ن ماج ًنمخ ن ممامجئ ن منذساساا ص، و ت،ضتح شعخ ن مبجسا ًنمخ ن ممامجئ ن منذساساا palestinehistory.com ان م،ى ن عت ،س :ن مصً 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 31 م،نى مماتمجئ ن الفان را ىسجي شقو (: ا،ضتح9شعخ) (1001،قن و ن تمساس ،ن تنج،ن ن ً، ا ) -ن مصً سذس مذج ا ن مبجسا ن ذعساا را ن مماتمجئ (: ا،ضتح1عخ)ش 101-150 m2 33% 50-100 m2 32% < 50 m2 2% >200 m2 15% 151-200 m2 18% < 50 m2 50-100 m2 101-150 m2 151-200 m2 >200 m2 سذس ًً س،نب ن مبجسا ًنمخ ن مماتمجئ (: ا،ضتح1شعخ) طابق ثالث 2% طابق ثاني طابق أول5% 16% طابق أرضي 77% طابق أرضي ل طابق أو طابق ثاني طابق ثالث )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً ًنمخ ن مماتمجئ 8ن سذس س،ي نألذ (: ا،ضتح1شعخ) اسرة نووية 71.4% اسرة ممتدة 24.8% اسرة مركبة 0.3% شخص واحد 3.5% اسرة مركبة اسرة ممتدة اسرة نووية شخص واحد ن ملتم ًنمخ ن مماتمجئح سذس بساا (: ا،ضت 1شعخ) طلبة وتالميذ 38% جامعيين 4% مسنيين 6% عّمال 10% عاطلين 23% أطفال 19% أطفال طلبة وتالميذ جامعيين مسنيين عّمال عاطلين 8 : أنواع األسرة .نأل، اا نألذ و ن مع،سا من ن ق،لان ، فسمج ،تتذ بذمجئ ن لمج ا اا :األسرة النووية .ن نبا ن ًم،اا ،،اا المن ج نإلىجما ن مشت عا ،ت ، ن ًو فذ س ن تانألذ و اا :الممتدة األسرة .ن لتمج اا مجئنن تق ، ن مشت عا نإلىجما،تلمن نألخ ،نألمئ ت ، ن ًو فذ و س،،اا ت تبس من ماخ مس نألس ف، نأل ف، ن تانألذ و اا : المركبةاألسرة لمحتلةا 48 أراضي 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 34 ًنمخ ن مماتمجئ 9ن سذس مذت،اجئ ن م (: ا،ضتح4شعخ) فقر مدقع 28% فجوة الفقر 46% فقر 26% فقر فقر مدقع فقر فجوة ال )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً سجئ جما من ًنمخ ن مماتمجئ ن منذساساا را ىسجي شقو (: ا،ضتح20شعخ) ا،س بج سذبا مًاسا مجن ا،س ممسس ممات مجن (: ا،ضتح22شعخ) –المصدر 2008( jouda, abdelkarim) 9 ،من اسج ا ه مذت،ى من ن ًمخ ا تجلم ن م ء ف، نألذ و ت اع،ن بجإلمعجن ت،را مذت،ى مناشا ماف را بنًٍ مجا، فًس( poverty line( ف، )poverty threshold) خط الفقر ات ، ه ا ،ن مذعن،ا، مذت،ى من ن م اتمثتخ بج نلق ن ت،را تعج اف ن متسنبجئ ن ًساج ن ض ، اا من اث ن م عخ ،ن منب ،ن جاا ن ص ا (absolute poverty) الفقر المدقعمصسنح متنج ف نام ج ماجع ،ن ا ً، ه ،را ت ًا آم ن من ماخ ن ملم،ي ن عنا نم،نً نألذجذاا ،ن تا اذت نع ج نألر نً ن بج ر،ن را ماخ رت و قمساا مناسا شج بجع ذسا الفقرخط مستوي ت ًاً . فم اعا ،ن ً را ن ا، نمً تس ا ن بج ث –ن مصً 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 90 سذس (: ا،ضتح21شعخ) منعاجئ نأل نضا سذس (: ا،ضتح21شعخ) مرجً و ن ممات سذس (: ا،ضتح21شعخ) ر جًو ت ااخ ن ممات سذس (: ا،ضتح24شعخ) ن ناف را ش ا اجار 1% خاص 33% ال اجابة 14% حكومية 52% نعم 22% ال 47% ال اجابة 31% نعم 70% ال 15% ال اجابة 15% نعم 7% ال 77% ال اجابة 16% )تس ا ن بج ث( -(1004)نأل،س ،ن( )،عج ا ش،ث ،تشراخ ن الفان -ن مصً سجئ من بنض ن مشعائ ن نجما ًنمخ ممات مجن ا،س الفان (: ا،ضتح10شعخ) ص، و ت،ضح ن تعً ن ذعجسا ،ضا ن ش،ن ي بان ن مبجسا ص، و ت،ضح سبانا ن مبجسا ن ذعساا ،تس، ج ضا ،متنًًو ن س،نب ()مبجسا ً، ن ص، و ت،ضح ذ،ء ن تشساس ن منمج ،ن تش،ج ن بص نمبجسا ص، و ت،ضح سبانا ن ترساجئ ب ،نح ن قاسع، ألذ ف ن مبجسا ص، و ت،ضح ذ،ء ن بساا ن ت اا نمما بنً ،لً، ص ف ماجج نألمسج ص، و ت،ضح ذ،ء ت عاس م،نذا ن ص ف من تضا نعذ ن ص ا ن مج لاا ن )تس ا ن بج ث( -ن مصً al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 81 nomographs and feasibility graphs for enumeration of ravigneaux-type automatic transmissions essam l. esmail lecturer college of engineering/university of qadisyah email:dr.essamesmail@yahoo.com abstract an automatic transmission is a device that connects an engine to the drive wheels. it keeps the engine within a certain angular velocity. although there are many epicyclic-type automatic transmissions in production, the related configuration design methods are still tedious and borne to human error. a simple methodology needs to be developed. therefore, the purpose of this research is to present a methodology for the systematic design of the ravigneaux-type epicyclic gear transmissions for automobiles. first, fundamentals and gear-shifting operations of the four-speed, and six-speed epicyclic-type automatic transmissions are illustrated to establish the design requirements. second, based on the kinematic nomographs of the corresponding basic gear ratios, a simple clutching-sequence method is proposed and illustrated. next, a planar-graph representation is presented to arrange the desired clutches for each possible clutching sequence into the epicyclic gear mechanism. then, with the above methods, the systematic designs of the epicylic gear mechanisms are given for demonstrating the feasibility of the proposed methodology. the result of this work shows that the seven-, eightand nine-link two-dof ravigneaux-type epicylic gear mechanisms could reach four-, six-, and eightforward speeds at most, respectively. the methodology can be applied to any transmission mechanism depending on its kinematic and geometric constraints. new five-, six-, sevenand eight-velocity automatic transmissions are enumerated from the two-ring eightand nine-link ravigneaux gear mechanisms. it is a major breakthrough to design completely satisfactory eight-speed automatic transmissions from the nine-link ravigneaux gear mechanism. keywords: automatic transmission, clutching-sequence, epicyclic gear train, eightvelocity, feasibility graphs, nomographs, ravigneaux gear set, systematic design. ليه آليات نقل الحركه اآل تصميمفي الجدوى استخدام مخططات النوموغراف ومخططات رافكنوز-نوع م.د.عصام العيبي اسماعيل جامعة القادسيه/كلية الهندسه nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 82 الموجز ماكنه االحتراق وتحافظ على عمل اكنه االحتراق الداخلي بالعجالت.آلية نقل الحركه هي الوسيله التي تقوم بربط م ضمن مدى محدد من السرع الدورانيه. وعلى الرغم من وجود الكثير من آليات نقل الحركه كواكبية النوع ، الداخلي يميه فأن طرق التصميم ذات الصله ما زالت مربكه وعرضه لالخطاء البشريه ، ومن الضروري تطوير طريقه تصم رافكنوز للسيارات الحديثه. -بسيطه. لذلك فأن من اهداف الدراسه تقديم طريقه منهجيه لتصميم آليات نقل الحركه نوع اوال : أيضاح المبادئ االساسيه لعمليات تبديل التروس آلليات نقل الحركه ذات السرع االربعه او ذات الست سرع االعتماد على مخططات النوموغراف الحركيه فقد تم أقتراح وأيضاح للتعرف على المتطلبات التصميميه. ثانيا : وب طريقه بسيطه لتعداد تعاشيق التروس المختلفه. بعدها تقديم تمثيل بمخطط مستوي لترتيب القوابض المرغوبه لكل منهجية تتابع التعاشيق الممكنه آللية نقل الحركه. ثم ، وباستخدام االساليب المذكوره اعاله ، تم استعراض تصاميم آليات نقل الحركه الحاليه الثبات جدوى المنهجيه المقترحه. وقد بينت نتائج الدراسه الحاليه بأن آليات نقل الحركه نوع رافكنوز ذات السبع والثمان والتسع صالت يمكن ان تعطي اربع او ست او ثمان سرع اماميه على حركه اخرى باالعتماد على قيودها الحركيه والهندسيه. وقد تم تعداد التتابع. ويمكن تطبيق الطريقه على اي آليه نقل ، وثمان سرع من آليات رافكنوز ذات الثمان والتسع صالت -، سبع -، ست -آليات نقل حركه جديده ذات خمس ذات والترسين الداخليين. وهو تقدم كبير ان يتم تصميم آليات نقل حركه ذات ثمان سرع من آلية رافكنوز الترسيه الوصالت التسع. introduction for a long time automatic transmissions with planetary gear trains are used in the automotive industry. ravigneaux in 1940 proposed sevenand eight-link two-degree-of-freedom (dof) epicyclic gear mechanisms [1, 2]. these epicyclic gear mechanisms are called the ravigneaux gear mechanisms. figure 1 shows an automatic transmission which provides three forward speeds and one reverse speed [3]. it consists of a seven-link two-dof ravigneaux gear mechanism, two rotating clutches c1 and c2 and two band clutches b1 and b3. in the associated clutching sequence table, xi indicates that the corresponding clutch is activated on the i th link for that gear. the ranges of output velocities are classified into two kinds: under drive (ud) and reverse drive (rd) according to whether the velocity is between zero and the input velocity, or less than zero. a "direct drive" (dd) is equal to the input velocity. the seven-link two-dof ravigneaux gear train has been developed by nearly all automotive manufacturers as threeor four-velocity automatic transmission [3]. it can be found in ford c3, ford c5, mercedes benz, toyota a40 and nissan, to name a few three-velocity automatic transmissions. it can also be found in km 175 and 176, ford aod, zf 4 hp 14 and borg–warner [4], to name a few four-velocity automatic transmissions [5]. figure 2 shows the zf 4 hp 14 automatic transmission [6], which can provide four forward speeds and one reverse speed. sometimes, the seven-link two-dof ravigneaux gear train is integrated with a simple epicyclic gear train to form ten-link three-dof epicyclic gear mechanisms to enhance the number of speeds [6, 7], providing six forward speeds. figure 3 shows lepelletier automatic transmission and its clutching sequence table [8]. a widespread gear set concept is that of lepelletier. this design is based on a single al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 83 planetary gear set with rear-mounted ravigneaux gear set. in 2001, zf [9] used this gear set design to bring the first 6-speed passenger car transmission 6 hp 26 on the market (figure 3). two-dof eight-link ravigneaux gear mechanism, shown in figure 4 (b) consists of a long pinion and two or more short pinions connecting two sun gears and two ring gears. unfortunately, two-dof eightlink ravigneaux gear trains have been developed as four-velocity automatic transmission [10] while they can be used to produce automatic transmissions having more than four speeds. this work in part will attempt to attain maximum sequential velocity ratios for any given epicyclic gear train. a seven-link 2-dof ravigneaux gear mechanism, an eight-link 2-dof ravigneaux gear mechanism and a nine-link 2-dof stepped ravigneaux gear mechanism are shown in figure 4, respectively. the literature on the design of planetary gear trains includes conceptual designs, kinematic analysis, power flow and efficiency analysis, and configuration designs. however, relatively little work has been done on the enumeration of clutching sequences and configuration design of egms. this paper presents a systematic procedure to enumerate clutching sequences and to find feasible clutch layouts for ravigneaux planetary gear trains. literature review the selection of an optimal clutching sequence can not be solved analytically. nadel et al.[11-13] formulated the task as a constraint satisfaction problem. hsieh and tsai [14, 15], hwang and huang [16] and hsu and huang [17] used algorithmic techniques. ross and route [18] and esmail [19] introduced graphic techniques. hattori et al. [20] used phase geometry method. nadel et al. applied an artificial intelligence technique to enumerate clutching sequences for egms made up of two basic epicyclic gear trains. the artificial intelligence technique is a powerful tool for solving the transmission design problem. however, the technique assumes that the design variables have discrete values in prescribed domains. furthermore, it requires a search over the entire feasible solution space. this methodology is suitable for pgts in which two simple pgts are combined. these shortcomings inevitably reduce the efficiency of the algorithm. hattori et al. [20] proposed twenty three phase geometric patterns for five-speed automatic transmissions, each could provide four clutching sequences. each feasible clutching sequence obtained could be used to construct a clutch layout. however, this approach is suitable only for pgts consisting of two sun gears, two ring gears and one to three meshed planet gears mounted on a common arm. ross and route [18] introduced a design tool based on a lever analogy. it includes calculation of gear ratios, gear trains selection, and the construction of clutch layouts for parallel-connected pgts. hwang and huang [16] and hsu and huang [17] used similar methods to that used by hsieh and tsai [14] to enumerate the clutching sequences of two-dof eight-link ravigneaux gear mechanism. moreover, the five studies cited above are restricted to constructing clutch layouts of automatic transmissions for specific types of pgts. hsieh and tsai [14] used the concept of fundamental gear entities (fges) proposed by chatterjee and tsai [21] in conjunction with their earlier kinematic study [22] to determine the most efficient clutching sequence associated with automatic transmission [15]. they applied combinatorial enumeration procedure to arrange the velocity ratios in a descending sequence. then, they used an algorithm to enumerate clutching sequences for egms composed of two or more fges. a computer algorithm for the enumeration of clutching sequences is given by hsieh [23]. the algorithm needs information containing the approximate gear sizes arranged in a descending order. most combinatorial enumeration procedures are done through the process of generating and testing. the procedure is thus divided into two parts: a generator of all possible solutions and a tester that selects only those solutions that meet the constraints. an important issue in using a generating and testing technique is the distribution of knowledge between the generator and tester. the generator produces solutions satisfying some of the constraints. the tester then selects those solutions that satisfy the rest of the constraints. while this technique is valid for solving transmission design problems, it nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 84 limits the solutions to the knowledge (information) contained in the generator and tester. this inevitably reduces the efficiency of this solution technique and needs complicated computer-algorithm. usually, putting more knowledge in the generator, results in a more efficient procedure. nevertheless, hsieh and tsai [14] did not develop an effective method of arranging clutch layouts for the synthesized clutching sequences. however, the elimination of invalid clutching sequences was conducted by inspection. identifying invalid clutching sequences by inspection is not always reliable. esmail [19] proposed a methodology, based on nomographs, for the enumeration of the associated clutching sequence table for an epicyclic gear mechanism. this method simplifies the synthesis of the clutching sequence of an epicyclic gear mechanism efficiently. without careful examination, a clutching sequence may be mistaken for a usable clutch layout for an automatic transmission. hsu and huang [17] proposed a planar-graph representation to arrange the desired clutches for each possible clutching sequence into the ravigneaux gear mechanism. hwang and huang [24] introduced coded sketches for connecting clutch elements to planetary gear trains for automotive automatic transmissions. the literature survey reveals that although some studies are made on the clutching sequence synthesis, they are all tedious. a simple methodology for the design of planetary automatic transmission needs to be developed. in this paper nomographs are used to synthesis the clutching sequences of ravhgneaux gear trains; the nomograph method is described in a series of previous papers [19, 25 and 26]. only the related topics needed in this paper will be reviewed wherever appeared. in this paper, more efficient solution techniques are developed to overcome those shortcomings. this paper applies kinematic nomographs [19, 25] and feasibility graphs [17] of ravigneaux gear trains to achieve the goal. by virtue of these solution techniques, completely satisfactory sixand eight-speed automatic transmissions are designed from the eightand nine-link ravigneaux gear mechanism, respectively. enumeration of all feasible clutching sequences with the aid of nomograph the first stage of designing epicyclic-type automatic transmissions is to synthesize all possible clutching sequences from the epicyclic-gear mechanism. nomographs are used for this purpose. nomographs and geometry relations for sevenlink ravigneaux gear train a nomograph is defined as three or more axes, or scales, arranged such that problems of three or more variables can be solved using a straightedge. in the particular case of egts, a nomograph can be constructed using three or more vertical parallel axes [19 and 27]. traditionally, the velocity ratio is used to study the velocity relations among the different links of an egt [3]. let the symbol r z yx, denote the velocity ratio between links x and y with reference to link z where x, y and z are any three links in the gear train, then zy zxz yxr     , (1) since the gear mechanism, shown in figure 4 (a) is a double-planet fge then its nomograph can be drawn in terms of planet gear 6 as shown in figure 5. the term "gear ratio" is used in this paper to denote the ratio of a meshing gear pair. it is defined by the ratio of a planet gear p with respect to a sun or ring gear x al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 85 xpxp zzn  , (2) where zp and zx denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative sign depends on whether x is a ring or sun gear. considering the kinematics of a fundamental circuit, the fundamental circuit equation can be written as [19]: xpcpcx n , )()(   (3) equation (3) can be re-written for ring, sun, planet gears and carrier to obtain n rp, , n sp, , n pp, and n cp, , respectively. the gear ratio for small sun gear ss that is not meshing directly with the first planet gear p on which the nomograph is drawn and is meshing with the second planet gear p1 can be found in terms of the gear ratio of the two planets np,p1 as nnn ss spppsp ,,, 11 . (4) the values of the gear ratios are used to place the axes of the nomograph shown in figure 5. the c axis passes at the origin, and the p axis is one unit apart from it. the gear ratios for the ravigneaux gear train are 565,6 zzn  (5) 252,5 zzn  (6) 161,6 zzn  (7) and 464,6 zzn  (8) considering the geometry relations of the ravigneaux gear mechanism given in equations (5) through (8), the values of the gear ratios can be deduced as following: 0 5,6  n (9) 0 2,5  n (10) 0 1,6  n (11) and 10 4,6  n (12) from eq. (4), we can write nnn 2,55,62,6 . (13) 262,6 zzn  (14) nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 86 since 4z is greater than 2z then from equations (8) and (14) it can shown that 4,62,6 nn  (15) 2.2. enumeration of all feasible clutching sequences kinematic relationships among the links of this fge can easily be visualized by observation from the nomograph shown in figure 5. any straight line through the input operating velocities of the egt will intersect other axes at the operating velocities of the links representing to those axes. from the nomograph r z yx, can be written as [19] zpyp zpxpz yx nn nn r ,, ,, ,    (16) because there are four coaxial links and link four is pre-assigned as the output link, this gear train can provide six overall velocity ratios [27 and 28]. figure 6 shows the clutching sequence nomograph for this mechanism. in arranging a clutching sequence, it is highly desirable to achieve a single-shift transition [19]. in order to achieve single-shift transitions, the uds can be further classified into two sets. the ods and rds are used with both of the ud sets. a direct drive is obtained by simultaneously clutching two coaxial links of an egt to the input power source. a reverse drive can be obtained by applying one or two of the clutches designed for the forward drives to the reverse drive. as a result, we obtain two descending sequences of velocities as shown in figures 7 (a) and (b), which result in two three-velocity and two four-velocity clutching sequences. 2.3. feasibility graphs for an epicyclic gear train to form an automatic transmission a graphical representation is proposed by [17] to easily and quickly detect the possibility of the arrangement of all the rotating clutches and band clutches into the gear mechanism to forming an automatic transmission. a graph that can be drawn on a plane such that no two of its edges intersect is called planar; meaning it can form an automatic transmission. a graph that cannot be drawn on a plane without crossover between its edges is called non-planar, meaning there is no possibility to form an automatic transmission. here we shall call such graphs as the feasibility graphs of a gear train to form an automatic transmission. they are shown in figure 8 (a) through (d). as a result, all of the four sets of clutching sequences are feasible to form automatic transmissions, and the corresponding four-velocity automatic transmissions are drawn, as shown in figures 9 (a) through (d), respectively. figure 9 (a) shows one feasible clutching sequence with rotating clutches attached to links 1 and 2, and band clutches attached to links 1 and 3. this clutching sequence has been applied in most threevelocity ravigneaux automatic transmission [3 and 6]. the other clutching sequences obtained are in agreement with those reported in the literature [5, 14, 23], except that there is no need to any information containing the approximate gear sizes arranged in a descending order. nomographs and geometry relations for eightlink ravigneaux gear train figure 10 shows the nomograph of the mechanisms shown in figure 4 (b). the gear ratios for the eight-link ravigneaux gear train are the same as that for the seven-link given before. in addition the gear ratio for the added small ring gear can be written as following: al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 87 757,5 zzn  (17) it can be concluded that 10 7,5  n . from eq. (4), we can write nnn 7,55,67,6 . (18) therefore; 767,6 zzn  (19) since 7 z is greater than 1z then from equations (7) and (19) 1,67,6 nn  (20) enumeration of all feasible clutching sequences because there are five coaxial links and link four or seven can be assigned as the output link, this gear train can provide twelve overall velocity ratios for each assignment. figure 11 shows the clutching sequence nomograph for this mechanism. in order to achieve single-shift transitions, the uds can be further classified into two sets. by adding a direct drive and two ods, a total of four six-velocity sets are obtained. a direct drive is obtained by simultaneously clutching two coaxial links of an egt to the input power source. as a result, we obtain four descending sequences of velocities as shown in figure 12. a reverse drive can be obtained by applying one or two of the clutches designed for the forward drives to the reverse drive. if a reverse drive is added three six-velocity clutching sequences can be enumerated for each set which result in twelve six-velocity clutching sequences. for the small ring to be an output link another twelve six-velocity clutching sequences can be enumerated. the first set can realize six-speed automatic transmission, while having three clutches and three brakes only. feasibility graphs for the two-ring epicyclic gear train to form an automatic transmission the feasibility graphs of the eight-link ravigneaux gear train to form automatic transmissions are shown in figure 13 (a) and (b). figure 13 (a) reveals that only a clutch can be attached to link 2. for the first and second sets of clutching sequences shown in figures 12 (a) and (b), they are controlled by c1, c2, c3, c7, b1, b2 and b7. as a result, all of the six clutching sequences that can be obtained from the first and second sets are feasible to form automatic transmissions. figure 13 (b) reveals that only a band clutch can be attached to link 1. the third and fourth sets of clutching sequences shown in figures 12 (c) and (d) are controlled by c1, c2, c3, c7, b1, b2, b3 and b7. as a result by excluding c1 from the clutching sequences nomograph, two clutching sequences are feasible to form five-velocity automatic transmissions. figure 12 (d) shows a clutching sequence nomograph without reverse drive based on the fourth reduction set. by excluding c1 from the clutching sequence nomograph, a five-velocity automatic transmission is possible. figure 14 shows the corresponding functional representation, with a band clutch b3 attached to link 3 for reverse drive. the input clutches c7 and band clutch b3 are applied for the reverse drive. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 88 nomographs and geometry relations for nine-link ravigneaux gear train figure 15 shows the nomograph of the mechanisms shown in figure 4 (c). the gear ratios for the stepped nine-link ravigneaux gear train are the same as those for the sevenand eight-link gear trains given before, except that the gear ratios are written in terms of the plant to which it is meshing, either gear 6 or 6 1 of the stepped plant. 767,6 1 1 zzn  (21) in addition, the gear ratio for the added third sun gear can be written as: 868,6 1 1 zzn  since z7 is greater than z1 and z6 is greater than z6 1 then from equations (7) and (21) it can be shown that 1,67,6 1 nn  (22) similarly 1,68,61 nn  and 1,67,6 8,61 1 n nn  . moreover 262,6 1 1 zzn  (23) since z4 is greater than z2 and z6 is greater than z6 1 then from equations (8) and (23) it can be shown that these gear ratios work oppositely; while one increase the gear ratio, the other decrease it, but, without loss of generality, we can select the most probable case where n6 1 ,2>n6,4. because there are six coaxial links and link four or eight can be assigned as the output link, this gear train can provide twenty overall velocity ratios for each assignment. the velocity ratios are classified into three groups; under-drive, over-drive and reverse drive. if there are more than two sets of velocity ratios in any group, they are further classified into all possible sets or subgroups based on the constraint that only one clutch can be shifted in each set. the velocity ratios in any set are arranged in a descending order, and then the corresponding clutching sequence is generated. possible clutching sequences are generated by combining the ud, dd, od, and rd subgroups together. figure 16 shows the clutching sequence nomograph for the nine-link ravigneaux gear mechanism shown in figure 4 (c). in order to achieve single-shift transitions, the ud velocities are classified into two sets (shown in figure 17). for the first set, the ud clutching sequences shown in figure 17 (a), are controlled by c2, b1, b3, b7 and b8, while those for the second set shown in figure 17 (b), are controlled by b2, c1, c3, c7 and c8. the feasibility graphs of the nine-link ravigneaux gear train to form automatic transmissions are shown in figures 18 and 23. for the first ud set, the clutching sequences, shown in figure 18, are controlled by c2, c3, c7, c8, b1, b3, b7 and b8. as a result, all of the ud and od clutching sequences that can be obtained from the first set are feasible to form automatic transmissions. the rds are only obtained from one of the rotating clutches c7 or c8 and one of the band clutches b3 or b7. figure 18 reveals that a clutch can not be attached to link 1, thus, the last three reverse clutching sequences shown in figure 17 (a) are inadmissible. as a result, only thirteen clutching sequences shown in figure 19 are feasible at this design stage. based on the first ud set of feasibility graph, the general clutching sequence layout for the nine-link ravigneaux gear train is shown in figure 20. all of the eight-velocity feasible clutching sequence layouts can be extracted from this general layout. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 89 in order to achieve single-shift transitions, the ods can be further classified into five sets; three sets consist of three-over-drives and two sets consist of two-over-drives. by combining the first set of ud clutching sequences with three sets of three-velocity od clutching sequences and three sets of rds, nine possible clutching sequences for eight-velocity automatic transmissions are feasible at this design stage as shown in figure 21. moreover, the first set of ud clutching sequences can also be combined with two sets of two-velocity od clutching sequences and three sets of rds, six possible clutching sequences for seven-velocity automatic transmissions are feasible at this design stage, as shown in figure 22. for the second set, since b2 is essential for the ud clutching sequences, then only band clutches can be attached to links 1 and 8 as shown in figure 23. therefore, the clutching sequences are controlled by c2, c3, c7, b1, b2, b3, b7 and b8. the clutch c2 has no role in the clutching sequence. as a result by excluding c2, three clutching sequences are feasible to form six-velocity automatic transmissions. in order to achieve single-shift transitions, the ods can be further classified into three sets consisting of three-over-drives. by combining the second set of ud clutching sequences with the three sets of three-velocity od clutching sequences and the one rd, three possible clutching sequences for six-velocity automatic transmissions are feasible at this design stage as shown in figure 25. based on the second ud set of feasibility graph, the general clutching sequence layout for the nine-link ravigneaux gear train to form six-velocity ravigneaux gear mechanisms is shown in figure 26. conclusions a novel feature of the suggested approach for constructing multi-axis nomographs is the ability to enumerate the feasible clutching sequences associated with two-ring eight-, and nine-link ravigneauxtype automatic transmissions. it is a major breakthrough to design a completely satisfactory six-speed automatic transmission from the two-ring ravigneaux gear train since it has only eight links. moreover, new eight-speed automatic transmissions are enumerated from nine-link gear mechanisms. the new designs make use of the benefits of the ravigneaux gear train and overcome the previous art difficulties. the completeness of the results cannot be confirmed since no publications exist for eightvelocity ravigneaux gear mechanisms. the proposed methodology can be used for the systematic design of any epicyclic-type automatic transmission. feasibility graphs have been also used as a design tool, allowing the designer to quickly selecting the most viable clutching sequence. references [1]ravigneaux, p., “gear box with freewheeling gear,” u. s. patent no. 2195783, 1940. [2]ravigneaux, p., “speed changing device,” u. s. patent no. 2220174, 1940. [3]tsai, l.w., “mechanism design: enumeration of kinematic structures according to function”, crc press, boca raton, fl, 2001. [4]wilfinger, e., and thompson, j., “borg–warner australia model 85 automatic transmission,” sae paper no. 880480, 1988. [5]c.h. hsu, r.h. huang, “systematic design of four-speed ravigneaux-type automatic transmissions,” journal of chinese society of mechanical engineers 30 (3) pp. 201–209, 2009. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 90 [6]naunheimer, h., bertsche, b., ryborz, j., novak, w.,”automotive transmissions, fundamentals, selection, design and applications”, 2 nd ed., doi 10.1007/978-3-642-16214-5_6, © springer berlin heidelberg, 2011. [7]katou, n., taniguchi, t., and tsukamoto, k., “aisin aw new six-speed automatic transmission for fwd vehicles,” sae paper no. 2004-01-0651, 2004. [8] lepelletier, p. a. g., “multispeed automatic transmission for automobile vehicles,” u. s. patent no. 5106352, 1992. [9]scherer, h., “zf 6-speed automatic transmission for passenger cars,” sae paper no. 2003-010596, 2003. [10] ravigneaux, p., “epicyclic change-speed gear,” u. s. patent no. 2761333, 1956. [11]nadel, b.a. and lin, j. (1991). automobile transmission design as a constraint satisfaction problem: first results, proc. 7th ieee conf. on artificial intelligence applications, 1, pp. 248-256. [12]nadel, b.a. and lin, j. (1991). automobile transmission design as a constraint satisfaction problem: modeling the kinematic level, artificial intelligence for engineering design, analysis and manufacturing, 5, 3, pp. 137-171. [13]nadel, b.a., wu, x. and kagan, d. (1993). “multiple abstraction levels in automobile transmission design: constraint satisfaction formulation and implementation,” int'l. journal of expert systems, 6, 4, pp. 489-559. [14]hsieh, h.i. and tsai, l.w. (1996), “a methodology for enumeration of clutching sequences associated with epicyclic-type automatic transmission mechanisms,” sae transactions, journal of passenger cars, sec.105, pp. 928-936. [15]hsieh, h.i. and tsai, l.w., the selection of most efficient clutching sequences associated with epicyclic-type automatic transmission, asme j. of mechanical design, 120, pp. 514-519, 1998. [16]w.m. hwang, y.l. huang, configuration design of six-speed automatic transmissions with twodegree-of-freedom planetary gear trains, transactions of the canadian society for mechanical engineering 29 (1), pp. 41–55, 2005. [17]c.h. hsu, r.h. huang, “systematic design of six-speed automatic transmissions with an eight-link two-dof ravigneaux gear mechanism,” transactions of the asme, journal of mechanical design, volume 13, no. 1, pp. 011004-1–011004-8, 2009. [18] c.s. ross, w.d. route, a method for selecting parallel-connected, planetary gear train arrangements for automotive automatic transmissions, sae transactions 100 (6) (1991) 1765–1774. [19]esmail, e. l.,"nomographs for enumeration of clutching sequences associated with epicyclic type automatic transmission mechanisms", asme international mechanical engineering congress and exposition (imece08), october 31november 6, 2008 boston, massachusetts, usa, paper no.66409 also at (emirates journal for engineering research, vol. 14, no.1, pp.29-38, 2009). al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 91 [20] n. hattori, t. oshidari, y. morimono, application of a new complex planetary gear set to fivespeed automatic transmission gear train, transactions of the society of automotive engineers of japan 26 (1) (1995) 79–82 [21]chatterjee, g. and tsai, l.w., “enumeration of epicyclic-type transmission gear trains,” transactions of sae, 103(6), paper no. 941012, pp. 1415-1426, 1995. [22]hsieh, h. i., and tsai, l. w., “kinematic analysis of epicyclic-type transmission mechanisms using the concept of fundamental geared entities,” asme j. of mechanical design, 118, pp. 294299, 1996. [23]hsieh, h.i., “enumeration and selection of clutching sequences associated with epicyclic-type transmission mechanisms,” ph.d. thesis, department of mechanical engineering, university of maryland at college park, maryland, usa, 1996. [24]w.m. hwang, y.l. huang, “connecting clutch elements to planetary gear trains for automotive automatic transmissions via coded sketches,” mechanism and machine theory 46, pp. 44–52, 2011. [25]esmail, e.l., “kinematic nomographs of epicyclic-type transmission mechanisms,” emirates journal for engineering research, volume 12, no. 3, pp. 47-55, 2007. [26]esmail, e.l., “nomographs for analysis of power circulation through closed epicyclic gear trains,” emirates journal for engineering research, volume 16, no. 2, pp. 1-9, 2011. [27] esmail, e. l. and hussien, h.a., "nomographs for kinematic, statics and power flow analysis of epicyclic gear trains", asme international mechanical engineering congress and exposition (imece09), november 13-19, lake buena vista, florida, usa, volume 13, paper no. 10789, pp. 631-640, 2009. [28] esmail, e. l., "teaching planetary gear trains with the aid of nomographs", to be published in advances in mechanical engineering hindawi, publishing corporation, 2013. figure 1 a typical automatic transmission mechanism and its clutching sequence table. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 92 figure 2 gearbox diagram for 2 zf 4 hp 14 4-speed automatic transmission with ravigneaux gear set (tc: trilok converter, p: pump, t: turbine, r: reactor with freewheel, td: torsion damper, f: freewheels, b: brakes, c: clutches) [6]. figure 3 six-velocity lepelletier automatic transmission and its clutching sequence table [8]. (a) (b) (c) figure 4 seven-, eightand nine-link ravigneaux gear mechanisms. figure 5 nomograph for the double-planet fgt shown in fig. 4 (a), in terms of planet gear 6, as given in ref. [19] al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 93 figure 6: clutching sequence nomograph for the ravigneaux gear train. (a) (b) figure 7: clutching sequence nomograph for (a) the first reduction set (b) the second reduction set. (a) (b) (c) (d) figure 8: feasibility graphs for the ravigneaux gear train to form threeor four-velocity automatic transmissions. (a) (b) (c) (d) figure 9: functional representation of the threeand fourvelocity ravigneaux automatic transmissions. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 94 figure 10 nomograph for the double-planet fgt shown in figure 4 (b), in terms of planet gear 6. [19] figure 11 clutching sequence nomograph for the ravigneaux gear train shown in figure 4 (b). al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 95 figure 12 clutching sequence nomographs for the first, second, third, and fourth sets. figure 13 feasibility graphs for the ravigneaux gear train to form fiveor six-velocity automatic transmissions. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 96 figure 14 functional representation of five-velocity ravigneaux gear train based on the fourth reduction set shown in figure 12 (d). figure 15 nomograph for the double-planet fgt shown in fig. 4 (c), in terms of planet gear 6. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 97 figure 16 clutching sequence nomograph for the nine-link ravigneaux gear train shown in figure 4 (c). (a) first ud set (b) second ud set figure 17 clutching sequence nomograph for the two uds of the nine-link ravigneaux gear train. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 98 figure 18 feasibility graph for the first ud set to form eight-velocity automatic transmission. figure 19 clutching sequence nomograph for the nine-link ravigneaux gear train shown in figure 4 (c) based on the feasibility graph. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 99 figure 20 clutching sequence layout for the nine-link ravigneaux gear train shown in figure 4 (c) based on the feasibility graph. figure 21 clutching sequence nomographs for eight-velocity transmissions. nomographs and feasibility graphs for enumeration of ravigneauxtype automatic transmissions 100 figure 22 clutching sequence nomographs for seven-velocity transmissions. figure 23 feasibility graphs for the ravigneaux gear train. al-qadisiya journal for engineering sciences, vol. 6, no. 1, year 2013 101 figure 24 clutching sequence nomograph for the nine-link ravigneaux gear train based on the second ud set feasibility graph. figure 25 the three feasible clutching sequences for six-velocity automatic transmissions. figure 26 clutching sequence layout for the nine-link ravigneaux gear train based on the second uds, ods and rds. microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 74 transient response of rotary regenerative heat exchanger by using finite difference method rehab noor mohammed al-kaby babylon university / college of engineering mechanical department abstract: a mathematical model for the unsteady state heat and mass transfer in regenerative rotary heat exchanger is derived and solved numerically by using finite difference method. triangular shape of the rotary matrix with silica gel (sio2) that used as desiccant material is taken here. the heat transfer coefficient and the mass transfer coefficient that used in the present study are suitable for different types of the matrix shapes. the unsteady state time effect, inlet air temperature, number of transfer unit (ntut), heat exchanger length, inlet air temperature and the desiccant material volume on the latent, sensible and total effectiveness are discussed. it has been notes that the increasing of the heat exchanger length, inlet air temperature, desiccant material volume and the (ntut) will increase the sensible, latent and total effectiveness. the increasing of the inlet air mass flow rate will decrease the total, latent and sensible effectiveness. the steady state time for the latent effectiveness is lower than the steady state time for the sensible and total effectiveness. keywords: heat exchanger, rotary, enthalpy exchange, latent and sensible heat transfer, finite difference, regenerative, counterflow. بأستخدام طريقه الفروقات المحددةدوار متجدد يدِل حرارالمباالستجابة الغير مستقره رحاب نور محمد قسم – آلية الهندسة -جامعة بابل الهندسة الميكانيكية الخالصة هذه المعادالت ْحلُّ وتم دِد متج دّواريّدِل حراراب داخل مالغير مستقرةالنتقال الحرارة والكتله رياضي النموذج اللقد تم اشتقاق مع مادةالدّوارِة لقد تم اخذ الشكل ألمثلثي للمصفوفة . )finite difference ( المحدودِةتالفروقا طريقِة باستعمالبشكل عددي هذه الدراسةخالل أستعمل الذي انتقال ألكتلهِل الحرارَة ومعامَل اقتناإّن معامَل . مجففةستعمَل آماّدة تي تال (sio2) تالسيليكا ، عدد الدخول للهواء، درجة حرارة الالزم للوصول إلى حالة االستقراِرتأثير الوقِت أن . مناسُب ألنواِع مختلفِة ِمْن أشكاِل المصفوفَة فاعلية المبادل الحراريعلى ةحجم المادة المجففوي، درجة حرارة الهواء الداخل حرارالّدِل امبالطول ، ) ntut( النقِل اتوحد درجة حرارة الهواء الداخل، حجم المادة ، طول المبادل الحراريتأثير زَيْاَدة لقد لوحظ ان . تم دراستهاالمحسوسة والكامنة والكلية الكلية زيادة آمية الهواء الداخل يؤدي إلى نقصان الفاعلية.والكامنة ان الفاعلية الكلية والمحسوسة النقِل َسَيِزيُداِتعدد وحدالمجففة و للوصول إلى حالة االستقرار بالنسبة للفاعلية الكامنة يكون اقل من الوقت الالزم للوصول مأن الوقت الالز. والكامنة المحسوسةو .إلى حالة االستقرار بالنسبة إلى الفاعلية المحسوسة والكلية al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 75 nomenclature a area (m2) ntum mass number of transfer unit m& mass flow rate (kg/sec) ntut thermal number of transfer unit c fluid capacitance (w / °c) nu nusselt number cp constant pressure mass heat capacity (kj/kg.k) p periphery area for equivalent diameter (m2) cr* fluid capacitance ratio pr prandtle number d diffusion coefficient (cm2/s) re reynolds number deq equivalent diameter (m) sc schmidt number f cross-sectional area for equivalent diameter (m2) sh sherwood number h enthalpy (kj/kg.k) t temperature ( ˚c) ha heat transfer coefficient (w/m2.k) u fluid velocity in the flow channel hm mass transfer coefficient (m/s) w moisture content (kg air/ kg water) k thermal conductivity (w/m.k) x longitudinal distance in x-direction (m) l length of the heat exchanger (m) z dimensionless longitudinal distance in x-direction le lewis number m mass (kg) greek θ rotational speed direction (s) υ kinematics viscosity (m2/sec) λ time interval ψ shape factor ∆ change γ constant factor in heat transfer equations ε heat exchanger effectiveness φ heat transfer factor µ dynamic viscosity (pa.sec) ζ effectiveness constant τ dimensionless time ρ density (kg/m3) γ dimensionless time constant subscript a air sa saturated air in inlet s supply x xdirection e exit θ θdirection r ratio m matrix desiccant material eq equivalent ut out j interval ∞ limiting case t thermal superscript i refer to distance j refer to time introduction energy recovery can substantially reduce the mechanical heating and cooling requirements associated with conditioning ventilation air in most locations and application. heating and cooling systems can be downsized and down cost when energy recovery is used, because energy recovery systems reduce peak heating and cooling requirements, [ashrae, 2005]. rotary regenerative heat exchangers have certain advantages over other types of heat exchangers for the recovery of heat from exhaust air [worsáe-schmidt, 1991]. two distinct advantages are that a considerably larger heat transfer area per unit volume and relatively less expensive, and this type of heat exchanger has higher effectiveness compared with other recovery heat exchanger. effectiveness of plate-type heat exchangers is between 45% and 65%, as compared to 60% and 80% for rotary regenerators [heinrich, and franzke, 1993]. besides these, the speed of the rotation of the matrix can be used to regulate the amount of the heat transferred. thus, rotary regenerative heat exchangers combine both compactness and high performance [skiepko, 1989]. rotary regenerators find increasingly frequent use in air-conditioning systems and gas turbine engines. they have a long history as air pre-heaters in steam power plants [romie, 1988]. in many researches considered, rotary heat exchangers that transfer sensible heat only and steady state operating conditions [klein et al., 1990, ciepliski et al., 1998, simonson et al., 1999 a and b]. kays and london, 1984, presented an “effectiveness-ntu” (ε-ntu) method for predicting the effectiveness of sensible recuperative and rotary regenerative heat exchangers as a function of dimensionless numbers. they showed that the effectiveness depends on two dimensionless numbers for sensible heat exchangers (ntu and cr) and four dimensionless numbers for rotary heat exchangers (ntu, cr, cr*, hsas / heae). bowlen, 1993, stated that the energy recovery in the cooling/dehumidifying mode can be up to 2.5 times greater than for an equally sized sensible heat al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 76 exchanger and approximately 40% greater in the heating/humidifying mode. gunnar stiesch, 1994, investigated experimentally the performance of the rotary regenerative heat and mass exchangers for different types of desiccants material to allow energy savings in the heating and cooling of ventilated buildings by recovering energy from the exhaust air and transferring it to the supply air stream for different types of the desiccants. joanna christen staton, 1998, discussed different types of polymeric desiccant materials and the ultimate goal of his study was to develop a material that, when applied to an existing air-to-air heat exchanger would achieve the necessary heat and mass transfer in a single process, thus transforming a sensible heat exchanger into a total enthalpy exchanger. his study focused on the development and determination of appropriate polymeric desiccant materials for use in different heat and mass transfer applications. various candidate materials were initially studied. buyukalaca, and yılmaz, 2002, presented a correction factor for the speed of the rotary heat exchanger effectiveness, this factor is used with traditional “effectiveness-ntu” method to estimate corrected value of rotary heat exchanger effectiveness. yilmaz and ukalaca, 2003, presented a calculation method for the design of rotary regenerators having different flow channel geometries. this method is dependent to correct the tradition heat exchanger calculation method “effectiveness-ntu” by introducing two factors for correction, one for rotational correction and other for the purge area. they showed this method is valid for rotational speeds between 0.05 and 7 rev/min. oyetope, 2005, studied the energy wheel effectiveness by a selected international laboratory for many types and sizes of wheel. his study used a new, low-cost, transient method to predict the effectiveness using only data obtained from transient measurements. in his study, an analytical model was presented for predicting the effectiveness of rotating energy wheels using only the characteristics measured on the same nonrotating wheels exposed to a step change in temperature and humidity. a relationship between the step response and the periodic response of an energy wheel is developed using first order linear system design theory. wang et al., 2005, developed a new experimental facility to study the transient response of sensors and equipment. they studied the transient response of a humidity sensor and used the same sensor to measure the relative humidity downstream of a non-rotating energy wheel following a step change in inlet air relative humidity. in the present study, a mathematical model is derived to generate the governing equations for the unsteady state countercurrent flow regenerative heat exchanger with mass and energy conservation, because these equations are impossible to solved analytically, then a numerical techniques is used to solve these equations by using finite difference method. triangular shape of the matrix and silica gel (sio2) is used as desiccant material in the present study because the silica gel is most popular desiccant material. it can selectively absorbs compounds of different molecular weights. mathematical formulation the assumptions that will be used in the present study are (figure (1)): 1the inlet and outlet state properties for the both fluids are uniform and not change with time. 2the thermodynamic properties of the air and the matrix are not affected by the pressure drop in axial direction of the matrix which is small compared to the total pressure. 3there is no mixing or carry out between the two fluid streams. 4the fluids and matrix states are considered to be uniform in radial direction. 5angular and axial heat conduction and vapor diffusion due to temperature and concentration gradient respectively are neglected. 6the matrix is considered to be a homogenous solid with constant matrix characteristics. 7the convective heat and mass transfer coefficient between the air streams and the matrix are constant throughout the system. 8the rotary regenerative heat exchanger operates adiabatically. 9the working fluids (inlet and exhaust) are air. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 77 the mathematical formulation of combined heat and mass transfer in unsteady state regenerative rotary heat exchanger can be derived by applying the mass and energy conservation on the rotary regenerative heat exchanger (figure (2)) compound with the previous assumptions, [joanna christen staton, 1998]: σ (the inlet air mass) – σ (the outlet air mass) = mass change of the desiccant matrix material with time with timematerialmatrix desiccant theof changemassmmmm ,out,ax,out,a,in,ax,in,a =−−+ θθ (1) x x m mm x,in,ax,in,ax,out,a ∆∂ ∂ −= and θ∆ θ∂ ∂ −= θθθ ,in,a ,in,a,out,a m mm (2) θ∆ θ∂ ∂ =θ∆ θ∂ ∂ −∆ ∂ ∂ − mm a a a a w m w mx x w m& (3) for the time interval λj λ λ θ∂ ∂ = λ λ θ∂ ∂ − θ∆ ∆ ∂ ∂ − jmm ja a a a w m w m x x w m& (4) lm x m x m l 1 m j,aaj,aa &&&& =θ∆ ∆ ⇒ ∆ θ∆ = (5) then, the final form can express as following: 0 w m w m x w lm jmm ja a a j,a =λ λ θ∂ ∂ + λ λ θ∂ ∂ + ∂ ∂ & (6) for the same procedures mentioned previously. applying the heat transfer balance for the system in order to get the energy equation, [joanna christen staton, 1998]: the advective heat transfer in the air = heat transfer to the desiccant matrix material wheel 0 h m h m x h lm jmm ja a a j,a =λ λ θ∂ ∂ + λ λ θ∂ ∂ + ∂ ∂ & (7) for the same procedures, applying the mass balance for the air and desiccant matrix material wheel, [gunnar stiesch, 1994]: )ww( m ahw )ww(h w a m ma aa mm mam m a a − ρ = τ∂ ∂ ⇒−= τ∂ ∂ ρ & & (8) mma aa m ma a a paa m h)ww( m ah )tt( t h cm hah − ρ +− ∂ ∂ = τ∂ ∂ && (9) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 78 the final heat and mass transfer governing equations based on mass and energy conservation combined with the assumptions for the rotary regenerative heat exchanger as follow, [gunnar stiesch, 1994]: 1mass conservation: 0 ww m z w ma r a = τ∂ ∂ + τ∂ ∂ + ∂ ∂ (10) 2energy conservation: 0 hh m z h ma r a = τ∂ ∂ + τ∂ ∂ + ∂ ∂ (11) 3mass transfer rate: )ww(ntu w mam m −= τ∂ ∂ (12) 4thermal energy transfer rate: mmamma a a t m h)ww(ntu)tt( t h ntu h −+− ∂ ∂ = τ∂ ∂ (13) the dimensionless parameters in eqs. (10 -13) as following, [gunnar stiesch, 1994]: jjj 1 0for γ ≤τ≤ γλ θ =τ ,where j,a m j m m &λ =γ ,and m j,a j m m&λ λ θ =τ (14) l x z = , paa a t cm ah ntu & = , aa m m m ah ntu ρ = & , m a r m m m = (15) the enthalpy of the moist air can expressed as following, [al-judi, 1983]: saaaawaaa hwhhhh +=+= (16) where ⎩ ⎨ ⎧ −>> <<− = c10t0t005.1 c60t0026.0t007.1 h aa aa aa o o (17) asa t84.12501h += (18) then, eq. (16) can be written as following: )t84.12501(w026.0t007.1h aaaa ++−= (19) a aa a w84.1007.1 026.0w2501h t + +− = and a aa a t84.12501 026.0t007.1h w + +− = (20) the enthalpy of the matrix desiccant can expressed as following, [ joanna christen staton, 1998]: mmpmm t)k.kg kj 18.4wc(h ×+= (21) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 79 the specific heat of desiccant (silica gel) known as a function of temperature, and the average value of the specific heat at the room temperature is [joanna christen staton, 1998]. 0.95645c m,p = (22) mmm t)w41800.95645(h += (23) due to the enthalpy and the temperature of the air are dependent on the longitudinal distance and the time, then: ha=ha(z,τ) and ta=ta(z,τ) (24) the chain rule is used to find the derivative of the air enthalpy with temperature, as following: a a a a a a t h t z z h t h ∂ τ∂ τ∂ ∂ + ∂ ∂ ∂ ∂ = ∂ ∂ (25) finite difference techniques: because of the analytical solution for the coupled partial equations with variable parameters is very complicated and difficult, the numerical solution is used. a finite difference technique is used to solve the eqs. (10-13), as following, [kreyszig, 1999]: 1mass conservation: 0 wwww m z ww j,im 1j,i m j,i a 1j,i a r j,1i a j,i a = τ∆ − + τ∆ − + ∆ − +++ (26) 2energy conservation: 0 hhhh m z hh j,im 1j,i m j,i a 1j,i a r j,i a j,1i a = τ∆ − + τ∆ − + ∆ − +++ (27) 3mass transfer rate: )ww(ntu ww j,i m j,i am j,i m 1j,i m −= τ∆ −+ (28) 4thermal energy transfer rate: j,im j,i m j,i am a a a aj,i m j,i at j,i m 1j,i m h)ww(ntu) t h t z z h )(tt(ntu hh −+ ∂ τ∂ τ∂ ∂ + ∂ ∂ ∂ ∂ −= τ∆ −+ (29) in order to solve the above equations, firstly determine the relative humidity for the air. substitution the eq. (28) in eq. (26), 0)ww(ntu ww m z ww j,i m j,i am j,i a 1j,i a r j,1i a j,i a =−+ τ∆ − + ∆ − ++ (30) ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ∆ − +− τ∆ −= + + z ww )ww(ntu m ww j,1i a j,i aj,i m j,i am r j,i a 1j,i a (31) j,1i a r j,i mm r j,i a r m r 1j,i a wzm wntu m w zm ntu m 1w ++ ∆ τ∆ + τ∆ +⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ∆ τ∆ − τ∆ −= (32) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 80 then from eq.(28) determine the relative humidity of the desiccant matrix material. )ww(ntuww j,im j,i am j,i m 1j,i m −τ∆+= + (33) j,i am j,i mm 1j,i m wntuw)ntu1(w τ∆+τ∆−= + (34) for the enthalpy, to determine the air enthalpy, substitution eq.(29) in eq.(27), ⎪ ⎭ ⎪ ⎬ ⎫ ⎪ ⎩ ⎪ ⎨ ⎧ =−+ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − τ∆ τ∆ − + − ∆ ∆ − −+ τ∆ − + ∆ − + + + +++ 0h)ww(ntu tt hh tt z z hh )tt(ntu hh m z hh j,i m j,i m j,i am j,i a 1j,i a j,i a 1j,i a j,i a j,1i a j,i a j,1i aj,i m j,i at j,i a 1j,i a r j,i a j,1i a (35 ) ⎪ ⎪ ⎭ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎩ ⎪ ⎪ ⎨ ⎧ =−+⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − ∆ ∆ − −+ ∆ − + − τ∆ τ∆ − −+ τ∆ − + ++ + ++ 0h)ww(ntu tt z z hh )tt(ntu z hh tt hh )tt(ntu hh m j,i m j,i m j,i amj,i a j,1i a j,i a j,1i aj,i m j,i at j,i a j,1i a j,i a 1j,i a j,i a 1j,i aj,i m j,i at j,i a 1j,i a r (36) ⎪ ⎭ ⎪ ⎬ ⎫ ⎪ ⎩ ⎪ ⎨ ⎧ =−+ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − − −+ ∆ − + − − −+ τ∆ − + ++ + ++ 0h)ww(ntu tt hh )tt(ntu z hh tt hh )tt(ntu hh m j,i m j,i m j,i am j,i a j,1i a j,i a j,1i aj,i m j,i at j,i a j,1i a j,i a 1j,i a j,i a 1j,i aj,i m j,i at j,i a 1j,i a r (37) j,i m j,i m j,i amj,i a j,1i a j,i m j,i a t j,i a j,1i aj,i a 1j,i a j,i m j,i a t rj,i a 1j,i a h)ww(ntutt tt ntu z 1 )hh( tt tt ntu m )hh( −−⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + ∆ −−=⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + τ∆ − + + + + (38) j,i m j,i a 1j,i a j,i m j,i a t r j,i m j,i am j,i a 1j,i a j,i m j,i a t r j,i a j,1i a j,i m j,i a t j,i a j,1i a j,i a 1j,i a h tt tt ntu m )ww(ntu tt tt ntu m tt tt ntu z 1 )hh(hh ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + τ∆ − − ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + τ∆ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + ∆ −−= ++ + ++ (39) j,i m j,i a 1j,i a j,i m j,i a t r j,i m j,i amj,1i a j,i a 1j,i a j,i m j,i a t r j,i a j,1i a j,i m j,i a t j,i a j,i a 1j,i a j,i m j,i a t r j,i a j,1i a j,i m j,i a t 1j,i a h tt tt ntu m )ww(ntu h tt tt ntu m tt tt ntu z 1 h tt tt ntu m tt tt ntu z 1 1h ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + τ∆ − − ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + τ∆ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + ∆ + ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎜ ⎜ ⎝ ⎛ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + τ∆ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − − + ∆ −= + + + + + + + (40) where: j,i a j,i a j,i aj,i a j,i a j,i a j,i a j,i a w84.1007.1 w2501026.0h t)t84.12501(w026.0t007.1h + −+ =⇒++−= (41) j,i m j,i mj,i m j,i m j,i m j,i m w41800.95645 h tt)w41800.95645(h + =⇒+= (42) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 81 these equations are solved by using trail and error (firstly determined the ha from eq. (40) at new time, then determined the ta from eq. (41) at a new time and replay the procedures to get the approached values of ha and ta with good accuracy. finally, the desiccant matrix material enthalpy is determined as following: j,i m j,i m j,i am a a a aj,i m j,i at j,i m 1j,i m h)ww(ntu) t h t z z h )(tt(ntu hh −+ ∂ τ∂ τ∂ ∂ + ∂ ∂ ∂ ∂ −= τ∆ −+ (43) ⎪ ⎭ ⎪ ⎬ ⎫ ⎪ ⎩ ⎪ ⎨ ⎧ −+ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − τ∆ τ∆ − + − ∆ ∆ − −= τ∆ − + + + ++ j,i m j,i m j,i am j,i a 1j,i a j,i a 1j,i a j,i a j,1i a j,i a j,1i aj,i m j,i at j,i m 1j,i m h)ww(ntu tt hh tt z z hh )tt(ntu hh (44) ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − − + − − −τ∆+−τ∆+= + + + + + j,i a 1j,i a j,i a 1j,i a j,i a j,1i a j,i a j,1i aj,i m j,i at j,i m j,i m j,i am 1j,i m tt hh tt hh )tt(ntuh))ww(ntu1(h (45) the time interval that used in the present analysis to avoid the negative fluctuation term in the above equations is derived from the eq. (32) and eq. (34) as following: 1zntu zm 0 zm ntu m 1 m r r m r +∆ ∆ ≤τ∆⇒≥ ∆ τ∆ − τ∆ − (46) or m m ntu 1 0ntu1 ≤τ∆⇒≥τ∆− (47) the lower value of the (∆τ) from the eq. (46) or eq. (47) will be selected in the computer program. a quick-basic computer program is written to calculate the values of the enthalpy, temperature and moisture content for the air and the matrix. boundary and initial conditions the conditions in the following analysis are taken as the summer conditions because this condition is very common through the year for arab countries ( table-1), [joanna christen staton, 1998]: the boundary and initial conditions that used during the solution process can be described as following. two sets of boundary conditions were required to allow for different, independent air conditions of the supply and exhaust air streams, different supply and exhaust boundary conditions must be imposed. for most realistic applications the exiting supply and inlet exhaust conditions would be dependent in some manner. when the passage of supply air over the surface of the desiccant channel is modeled, the solution satisfies the supply air boundary conditions: aia t),0(t =τ , and aia w),0(w =τ (48) when the passage of exhaust air over the surface of the desiccant channel is modeled, the solution satisfies the exhaust air boundary conditions: aea t),l(t =τ , and aea w),l(w =τ (49) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 82 the initial conditions applied to the governing equations, regardless of which air flow is being analyzed first, are: aia t)0,z(t = , and aia w)0,z(w = (50) the area of the hot and cold air flow are taken as following (hot air passage area =cold air passage area = (165˚/360˚) of the total area of the wheel, and the purge passage area = (30˚/360˚) of the total area of the wheel). then after applying the boundary and initial conditions, we calculate the humidity and enthalpy of the air and the matrix are calculated from the eq.(32), eq. (34), eq. (40) and eq. (45) , respectively. heat transfer coefficient yılmaz and cihan [1993] developed a method to calculate the convective heat transfer coefficient for flow in the channels of various cross-sections for a constant wall temperature boundary condition and showed the nusselt number can be calculated by using the following equation: 3132 3 3 3 3 a nu 8.0 nu 212.4 1nunu ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ γ φψ − γ φψ += ∞∞ ∞ (51) in which nu∞ is the nusselt number for the limiting case of z→ ∞ and can be obtained as follows: φ=∞ 657.3nu (52) where φ is a heat transfer factor taking the shape of the cross-section of the channel into account for developed velocity and temperature profiles at a constant wall temperature. it is given by [yılmaz and cihan, 1993]: ∆φ+ −+ −φ +=φ ∞ )1n/(11 1 1 (53) the parameters φ∞ and ∆φ can be calculated by using the following equations: ∗ ∗ ∞ − =φ d3 d 5155.0 2 (54) 3 5.0 max )1n(038.01 )1n(95.0 −+ − +∆φ=∆φ (55) where 2128828 8 max )d10*641)(d101( d007.0 ∗−−∗ ∗ ++ =∆φ (56) the parameters (d*) and (n) used in the equations above describe the shape of the channel [yılmaz and cihan, 1994]: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 83 max eq d d d =∗ and eqeq p p f f n == (57) where (feq) and (peq) are, respectively, the cross-sectional area and periphery of the equivalent diameter of the flow channel. the corresponding values for (d*) and (n) are given in fig. (3). equivalent diameter (deq) is defined as [yılmaz and cihan, 1994]: p f4 d eq = (58) where (dmax) is the diameter of the largest circle that can be inscribed in the cross-section of the flow channel. the shape factor (ψ), which is required for the calculation of nusselt number, is given as [yılmaz and cihan, 1994]: )1n/(d33.01 1 1 25.2 −+ −ψ +=ψ ∗ ∞ (59) where )d3(d 8 3 2 ∗∗ ∞ −=ψ (60) the other parameters that used in calculation of the nusselt number as following [yılmaz and cihan, 1994]: )1n/(25.01 1)]d1/()2/d(3[ 1 87 −+ −+ +=φ ∗∗ and prred l eq =γ (61) where ν = eq du re (62) a eqa a k dh nu = (63) mass transfer coefficient the common equation that used to calculate the mass transfer coefficient is, [incoropera and dewitt, 2002]: 44.083.0 scre023.0sh = (64) where sh is called sherwood number ( d dh sh eqm= ), sc is called schmidt number ( dd sc ρ µ = ν = ) and d is diffusion coefficient (cm2/s) rotary regenerative heat exchanger performance: the performance of the rotary regenerative heat exchanger is calculated by three types of the effectiveness: the sensible ( εs ), latent ( εl ) and total ( εt ) effectiveness. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 84 energy from rotary heat exchanger is transferred both sensible and latent energy between the air streams due to the desiccant attached to the aluminium substrate of the wheel matrix. sensible energy transfer is caused by the temperature differences between the two airstreams and latent energy transfer is caused by the water vapour pressure differences between the two airstreams. the total energy transfer rate in energy wheels is the sum of both sensible and latent energy transfer rates. the effectiveness is described as following: )(m )(m in,ein,smin soutins ζ−ζ ζ−ζ =ε & & (67) where ζ = is equal either the dry bulb temperature, the humidity ratio, or the enthalpy of the moisturecarrying air stream. when temperature is used, a sensible effectiveness is obtained, reflecting the wheel’s ability to transfer heat. when humidity ratio is used, a latent effectiveness which reflects the wheel’s moisture transfer performance is obtained. when enthalpy is used, a total effectiveness is obtained, reflecting the wheel’s ability to transfer both heat and moisture. minm& = is the minimum value of either sm& or exitm& also, in the present analysis a dimensionless parameter used with the enthalpy heat exchanger is called lewis number (le), [schultz , 1987], it is defined as the ratio of the number of transfer units for heat transfer to the number of transfer units for mass (humidity) transfer, as follows: w t ntu ntu le = (68) in the rotary regenerative heat exchanger, lewis number is very affected factor. the lewis number depends on the type of desiccant used and the thickness of the desiccant coating. when the lewis number greater than one, this means decreasing in the humidity transfer effectiveness compared with the thermal effectiveness for a fixed conditions of inlet states. results and discussion before discussion the results, the accuracy of the q. basic computer program is checked with the other results [gunnar stiesch, 1994], for the data (le =1, ts,in=25˚c, te,in=35˚c, triangular matrix duct, matrix length =0.15 m, matrix diameter =2 m, silica gel). the comparison is plotted in fig. (4), the results of the current program for the sensible heat exchanger effectiveness are very acceptable with the results of the gunnar stiesch, 1994. the variation of the temperature and enthalpy of the inlet air against the dimensionless time is plotted in fig. (5). the increase of the dimensionless time will increase the temperature and enthalpy due to increase the time for the energy transfer from the hot to cold fluid (air). the effect of the dimensionless time on the rotary regenerative heat exchanger effectiveness for (ntut=4 and le =2) is plotted in figure (6). the increase of the time will increase the sensible, latent and total effectiveness. the sensible effectiveness is increased as the time increased due to transfer of the sensible heat (temperature) from the hot fluid to cold fluid by the desiccant material. the latent effectiveness is increased due to transfer of the relative humidity from the exhaust humid air to the inlet fresh air and then reaches to steady state faster than the sensible heat effectiveness due to the mass transfer by relative humidity which need less time compared with heat transfer by temperature to reach the steady state value. the total effectiveness is also increases because it is the summation effect of the sensible and latent effectiveness. the steady state time for the sensible and total effectiveness is approximately identical and it’s greater than the steady state time for the latent effectiveness. in fig. (7), the variation of the sensible heat effectiveness is plotted against the dimensionless time constant for different values of the number of transfer unit (ntut). the increase of the time al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 85 will increase the sensible effectiveness. the increase of the ntu value will increase the sensible effectiveness due to increase of the quantity of the sensible energy that transferred from the hot fluid to the cold fluid. the difference in the steady state sensible effectiveness value for larger values of the ntut is become not noticeable due to the system nearly reach to the steady state faster (higher effectiveness) than when the ntut value is small (lower effectiveness). the increasing of the ntut will increase the steady state value due to increase of the heat transfer between the hot fluid and cold fluid. the same effect is appearing for the total effectiveness with dimensionless time for different values of the ntut (as shown figure (8)). due to the steady state, the total effectiveness is directly proportional to the steady state sensible effectiveness. the effect of dimensionless time on the sensible effectiveness for different values of the inlet air temperature is plotted in figure (9). the increasing of the inlet air temperature will increase the sensible heat effectiveness value due to reduce of the maximum heat transfer and in same time increase the energy of the inlet air. also, the effect of the number of transfer unit on the sensible effectiveness for different values of the inlet air temperature is plotted in fig. (10). the increasing of the inlet temperature and the number of the transfer unit increases the sensible effectiveness for the same reasons mentioned before. the effect of the heat exchanger length (matrix wheel length) against the steady state sensible, latent and total effectiveness is plotted in the figure (11) for (ntut=7 and le =2). the increase of the heat exchanger length will increase the steady state sensible, latent and total effectiveness due to increase the exchange time for the energy and mass transfer between the fluids. the effect of the heat exchanger length on the steady state value of the latent effectiveness is not noticeable compared with the steady state value of the sensible and total effectiveness because the latent effectiveness needs less time to reach the steady state value compared with sensible and total effectiveness. the effect of the inlet air mass flow rate on the steady state sensible, latent and total effectiveness is plotted in figure (12). the increase of the inlet air mass flow rate decreased the steady state sensible, latent and total effectiveness due to decrease the number of transfer unit (ntu) for heat and mass transfer. the increase of the mass flow rate will increase the inlet air storage energy and then the inlet air needs more thermal and mass energy in order to rise its temperature and its relative humidity. the effectiveness decreased firstly and this decreasing becomes sharply at high values of the inlet air mass flow rate the reason is the maximum heat transfer and maximum mass transfer become large compared with the actual mass and energy transferring. the effect of the desiccants material mass on the sensible, latent and total effectiveness is plotted in figure (13). the increasing of the desiccants material mass (volume) will increase the energy storage inside the desiccant material (internal energy) and then increases the transferred energy from the hot fluid to the cold fluid through the desiccant material. conclusions: the heat and mass transfer from a rotary regenerative heat exchanger is solved numerically by using finite difference techniques. the following conclusions that drawn from the results of the present work: 1the increasing of the time will increase the sensible, latent and total effectiveness. 2the steady state point for the latent effectiveness is less than the sensible and total effectiveness. 3the increasing of the ntu will increase the effectiveness and reduce the time for reaching the steady state value. 4the increasing of heat exchanger length will increase the sensible and total effectiveness sharply compared with latent heat effectiveness (the increase of the heat exchanger length not affected largely on the latent effectiveness). al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 86 5the increasing of the inlet air flow rate will decrease the sensible, latent and total effectiveness. 6the increase of the desiccant material mass (thickness) will increase the total, sensible and latent effectiveness. 7neglecting the latent heat transfer is not acceptable because the difference between the sensible and the latent effectiveness is noticeable. 8the using of traditional ε ntu method and the lmtd method for this system without any corrections may be lead to mistake in the calculations. references • ashrae, “air-to-air energy recovery”, hvac system and equipments handbook, chapter 44, american society of heating, refrigerating and air conditioning engineers inc., atlanta, 2005. • worsáe-schmidt, p., “effect of fresh air purging on the efficiency of energy recovery from exhaust air in rotary regenerators”, rev. int. froid, vol. 14, pp. 233–239, 1991. • heinrich, g., and franzke, u., “warmeruckgewinnung in luftungstechnischen anlagen”, verlag c.f. m¨uller, heidelberg, 1993, cited from ref. (12). • skiepko, t., “effect of parameter values on gas and matrix temperature fields in rotary heat exchangers”, int. j. heat mass transfer; vol. 32, no. 8, pp.1443–1472, 1989. • romie, f. e., “transient response of rotary regenerators”, transactions of asme, journal of heat transfer, vol. 110,pp. 836–840, 1988 • klein, h., klein, s.a. and mitchell, j.w., 1990, “analysis of regenerative enthalpy exchangers”, international journal of heat and mass transfer, 33, 735-744. • ciepliski, d.l., simonson, c.j. and besant, r.w., 1998, some recommendations for improvements to ashrae standard 84-1991, ashrae transactions 104(1b), 16511965. • simonson, c.j. and besant, r.w., 1999a, “energy wheel effectiveness: part i – development of dimensionless groups”, international journal of heat and mass transfer 42, 2161-2170. • simonson, c.j. and r.w. besant, 1999b, “energy wheel effectiveness: part ii – correlations”, international journal of heat and mass transfer 42, 2171-2185. • kays w.m., london a.l.; “compact heat exchangers”, 3rd ed.; mcgraw-hill book co.; new york, ny, 1984 • bowlen, k. l., “energy recovery from exhaust air for year round environmental control”, 1993. • gunnar stiesch, “performance of rotary enthalpy exchangers”, master thesis, university of wisconsin-madison, 1994. • joanna christen staton, “heat and mass transfer characteristics of desiccant polymers”, master thesis, virginia polytechnic institute and state university, 1998. • buyukalaca, o., and yılmaz, t., “influence of rotational speed on effectiveness of rotary-type heat exchanger”, heat and mass transfer, vol. 38, no. 4–5, pp. 441–447, 2002. • yilmaz t. and orhan b ukalaca, “design of regenerative heat exchangers” heat transfer engineering, vol. 24, no. 4, 2003, pp. (32–38). • oyetope omobayode abe, “effectiveness of energy wheels from transient measurements”, master thesis, university of saskatchewan, saskatoon, canada, 2005. • wang, y.h., simonson, c.j., besant, r.w., and shang, w., 2005, “transient humidity measurements and characteristics for humidity sensors and energy wheels”, ashrae transactions, 111(2). al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 87 • reilly, s., and van geet, o., “laboratories for the 21st century energy analysis: best practices”, u.s. environmental protection agency and u.s. department of energy federal energy management program, publication no. doe/ go1020031774, prepared by the national renewable energy laboratory, october 2003. . 1983صرة ،جامعة الب" أنظمة التكييف والتبريد"، )al-judi(الدآتور خالد الجودي • • kreyszig, e., 1999, “advanced engineering mathematics”, wiley, new york. • yılmaz, t., and cihan, e., “general equation for heat transfer for laminar flow in ducts of arbitrary crosssections”, int. j. heat mass transfer, vol. 36, no. 13, pp. 3265–3270, 1993. • yılmaz, t., and cihan, e., “ leveque solution for heat transfer in ducts of arbitrary cross-sections”, journal of thermal sciences and technology, vol. 17, no. 2, pp. 19–23, 1994. • f.p. incoropera and d.p. dewitt, “fundamentals of heat and mass transfer”, john willey and sons, new york, 2002. • schultz, k. j., “experimental analysis of a rotary silica gel dehumidifier”, asme, winter annual meeting of combined heat and mass transfer in porous media, 1987 figure (1) : cross sections of enthalpy regenerative heat exchanger, [reilly and van geet, 2003] table (1): specifications of the case study standard supply return dry bulb temperature (oc) 35 21 wet bulb temperature(oc) 26 16 relative humidity (%) 47 60 humidity ratio (kg h2o / kg air) 0.017 0.009 mass flow rate (kg/s) 0.22 0.4 silica gel density = 1200 kg/m3 aluminum foil density = 2700 kg/m3 and the specific heat (cpal)= 903 j/kg·k rotary heat exchange wheel length = 0.1 m rotary heat exchange wheel diameter = 1 m the other needed air properties is determined from the psychometric chart al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 88 figure (2) : schematic of enthalpy regenerative heat exchanger, [gunnar stiesch, 1994] figure (3) : the parameters d* and n for different channel shape [yilmaz and ukalaca, 2003] 0 2 4 6 8 10 12 the dimensionless time (τ) 0 20 40 60 80 t he s en si bl e h ea t e xc ha ng er e ff ec ti ve ne ss ( ε s ) comparsion the present study gunnar stiesch, 1994 figure(4): comparison between the present study and gunnar stiesch, 1994, (le =1, ts,in=25˚c, te,in=35˚c, triangular matrix duct, matrix length =0.15 m, matrix diameter =2 m, silica gel) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 89 0 2 4 6 8 10 12 14 the dimensionless time (τ) 35 36 37 38 39 in le t a ir c on di ti on s ( e it he r t em pe ra tu re (t a) (° c ) o r e nt ha lp y (h a) (k j/ kg .k )) inlet air temperature (oc) enthalpy (kj/kg.k) 0 2 4 6 8 10 the dimensionless time ( τ ) 0 0.2 0.4 0.6 0.8 t he h ea t e xc ha ng er e ff ec ti ve ne ss ( ε ) effectiveness total effectiveness sensible effectiveness latent effectiveness figure(6): the total, sensible and latent effectiveness for the heat exchanger against the dimensionless time for (ntut = 4 and le = 2) figure(5): the variation of the temperature and enthalpy of the inlet air against the dimensionless time al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 90 0 1 2 3 4 5 the dimensionless time constant (γ) 0 0.15 0.3 0.45 0.6 0.75 0.9 t he s en si bl e e ff ec ti ve ne ss (ε s) sensible effectiveness ntut = 1 ntut = 2 ntut = 3 ntut = 4 ntut = 5 ntut = 6 ntut = 7 ntut = 8 ntut = 9 ntut = 10 0 1 2 3 4 5 the dimensionless time constant (γ) 0 0.15 0.3 0.45 0.6 0.75 0.9 t he t ot al e ff ec ti ve ne ss (ε t) sensible effectiveness ntut = 1 ntut = 2 ntut = 3 ntut = 4 ntut = 5 ntut = 6 ntut = 7 ntut = 8 ntut = 9 ntut = 10 figure.(7): the effect of the dimensionless time constant (γ) on the sensible effectiveness for different values of the ntut figure (8): the effect of the dimensionless time constant (γ) on the total effectiveness for different values of the ntut al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 91 figure (9): the effect of dimensionless time (τ) on the sensible effectiveness for different values of the inlet air temperature figure (10): the effect of the number of transfer unit on the sensible effectiveness for different values of the inlet air temperature al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 92 0 0.2 0.4 0.6 0.8 the heat exchange length ( z ) (m) 30 40 50 60 70 80 t he h ea t e xc ha ng er e ff ec ti ve ne ss effectiveness total effectiveness ( εt ) sensible effectiveness ( εs ) latent effectiveness ( εl ) 0 0.2 0.4 0.6 0.8 1 1.2 the inlet air mass flowrate (kg/sec) 0 20 40 60 80 100 t he h ea t e xc ha ng er e ff ec ti ve ne ss effectiveness total effectiveness ( εt ) sensible effectiveness ( εs ) latent effectiveness ( εl ) figure (11): the effect of the heat exchanger length on the total, sensible and latent effectiveness (ntut = 7 and le = 2) figure (12): the effect of the inlet air mass flow rate on the sensible, latent and total effectiveness al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 93 0 400 800 1200 1600 2000 the mass of the desiccants material (kg) 0 20 40 60 80 100 t he h ea t e xc ha ng er e ff ec ti ve ne ss effectiveness total effectiveness ( εt ) sensible effectiveness ( εs ) latent effectiveness ( εl ) figure(13): the effect of the desiccants material mass on the sensible, latent and total effectiveness template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 338 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. effect of composite action of concrete slab on unsymmetrical steel plate girder under combined bending and torsion moments alaa m. a. al-khekany university of al-qadisiah, iraq e mail : alaa.alkhekany@qu.edu.iq alaa_msc1984@yahoo.com haitham h. muteb university of babylon, iraq e mail : eng.haitham_muteb@gmail.com received on 13 april 2017 accepted on 9 august 2017 abstract: in general, the reinforced concrete slab in composite unsymmetrical steel plate girder contributes in increased the ultimate strength of composite section under combined effect of bending and torsion moments. the contribution value of slab in composite section is unknown, so this study is adopted. six specimens were either non-composite or composite reinforced concrete slab and with symmetrical/unsymmetrical steel plate girders were adopted in this study. the specimens were divided into three non-composite steel plate girders and the others were composite with rc slab. the specimens were tested under effect of combined bending and torsion moments. the general behavior and response of the tested specimens were recorded and discussed in this paper. for each tested plate girder, the ultimate strength, load at cracking, failure's mode, and load/deflection relationship at mid-span and under points load were gaged. the experimental results show that the concrete slab contributes in increasing the ultimate load of composite section by a ratio (53.85)% for symmetrical section and (155.63 – 242.51)% for unsymmetrical section when the composite girder under loaded out of supported plane, and the contribution value of concrete slab in composite plate girder increased in unsymmetrical section than symmetrical section this is due to the ideal use of materials. keywords: unsymmetrical plate girder, composite section, combined bending and torsion moments. 1.introduction plate girders can be characterized as a beams built up from plate components to satisfy a more efficient arrangement of material than is provided with rolled beams or to manufacture a large size girder that cannot be manufactured as a hot or rolled sections. these built up elements (both flanges and webs) may be mailto:alaa.alkhekany@qu.edu.iq mailto:alaa_msc1984@yahoo.com mailto:eng.haitham_muteb@gmail.com al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 339 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. compact, non-compact or slender but these girders are usually very deep so that their webs will be either non-compact or slender. plate girders are considered as an economical section this is due to their properties. these properties are represented by long span and allow to sparing in expense proportioning for specific necessities. the cross area of plate girders can take a few forms such as box girder which providing improved torsional stiffness for curve long span, and (i) section which represents an effective section use in of material for maximizing stiffness. these plate girders may be of riveted or welded construction. they are additionally might be double symmetrical, single symmetrical or unsymmetrical plate girders. sometimes in plate girders, the strength of steel flange is higher than in web or webs at this case it is called hybrid plate girders [1]. concrete slab, in almost cases, is used to be in a composite action with steel girder to increase the ultimate load capacity of section. in composite section, concrete slab and steel girder are connected to gather by shear connectors. in general, concrete slab and top flange of steel girder are used to resist the compression stresses due to applied load while the bottom flange is used to resist the tension stresses. the used of composite steel plate girder with unsymmetrical flanges will improve its ultimate load capacity of section under combined effect of bending and torsion moments [2] [3]. the main objective of this investigation is to predict the contribution value of concrete slab in the ultimate load of composite section and the effect of concrete slab composite action with unsymmetrical steel plate girder on the ultimate load under combined effect of bending and torsion moments. 2.experimental work the experimental work contains tested six specimens which divided into two groups. first group represented by three specimens of noncomposite steel plate girders; one specimen had symmetrical cross section and the others had unsymmetrical cross section i.e. unsymmetrical flanges. the second group also represented by three composite steel plate girders with same steel girders that in first group. high strength concrete (hsc) is used in casting concrete slab of composite section. all specimens loaded out of supported plane to be under combined effect of bending and torsion moments. the experimental test was carried out in the site work at college of engineering\ al-qadisiyah university. 2.1. specimens description six built up (i-shape) steel plate girders specimens were designed and manufactured and tested as part of the experimental program. all specimens have (2000mm) length and (350mm) depth. the specimens classification according to composite action, three girders were noncomposite steel girders and three girders were composited with reinforced concrete deck slab has a dimensions (500mm) width and (80mm) thickness. two of these girders have symmetrical section and four girders have unsymmetrical section (unsymmetrical flanges). in composite specimens, a partial bond interaction between steel girder and reinforced concrete slab are used in this study. single hooked shear connectors are used for bond interaction. hooked shear connectors welded over center of girder's compression flange which spaced at (100mm). a hooked shear connectors are adopted in this study where a reinforcing steel bar (8mm diameter) is utilized in manufactured of hooked shear connectors; its length (45mm) and hook (25mm) can be written as (∅8mm-l45mm-h25mm). table(1) and figure(1) explain geometrical details and specimen designation of steel plate girders that adopted in this investigation. two of these specimens (composite and noncomposite specimens) had a symmetrical plate girder i.e. symmetrical flange width (symbol by s) with width of both top and bottom flanges (bft = bfb =100mm) and web thickness (3mm) (symbol by w3). these specimens are denoted by (nc.s.w3.bt and c.s.w3.bt.p), respectively. the other specimens had a two cases study of unsymmetrical flanges width represented by (us1 and us2) differ by flange's width where us1 has top flange width (bft = 80mm) and bottom flange width (bfb = al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 340 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 120mm) while us2 has (bft = 60mm) and (bfb = 140mm). these specimens are denoted by (nc.us1.w3.bt, nc.us2.w3.bt, c.us1.w3.bt.p, and c.us2.w3.bt.p), respectively. table(1) girders description, designation and geometry all specimens have tf = 6mm and hw = 350mm description of specimen specimen designation geometry, (mm) bft bfb tw symmetrical non-composite steel plate girder nc.s.w3.bt 100 100 3 unsymmetrical non-composite steel plate girder nc.us1.w3.bt 80 120 3 nc.us2.w3.bt 60 140 3 symmetrical composite concrete steel plate girder c.s.w3.bt.p 100 100 3 unsymmetrical composite concrete steel plate girder c.us1.w3.bt.p 80 120 3 c.us2.w3.bt.p 60 140 3 c.us1.w2.bt.p 80 120 2 c.us2.w2.bt.p 60 140 2 (a) noncomposite steel plate girder (b) cross section of symmetrical and unsymmetrical noncomposite plate girder figure(1) geometrical details of specimens al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 341 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (c) composite concrete steel plate girder (d) cross section of symmetrical and unsymmetrical composite concrete steel plate girder with partial bond interaction figure(1) geometrical details of specimens (continued) 2.2. materials high strength concrete (hsc) is used in this investigation and its production required prepares special materials. hsc contains mineral and chemical admixtures in addition to the main materials that used in production nsc (cement, sand, gravel and water). these materials were tested in laboratories of engineering college of al-qadisiyah university. the concrete materials properties that used in this study will discussed in the following. 2.2.1. cement ordinary portland cement (iraqi manufacturing) named al-jesser was utilized in this study for casting all the concrete specimens. this complies with iss no.5-1984[6]. these testing completed in the laboratory of engineering college/al-qadisiyah university. 2.2.2. fine aggregate natural sand from karbala was utilized in this investigation. the tests results demonstrated that it's grading and sulfate content complies with iraqi specification no. 45/1984 \ zone (2)[6]. these tests were done in the laboratory of engineering college/al-qadisiyah university. al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 342 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.2.3. coarse aggregate natural gravel has a max. particle size 10 mm (crushed surfaces gravel) from al-nibaey was utilized in present study. the course aggregate was cleaned and washed several times then let for dry in air. it tested and found that it duplicated to the specified limits by the is no.45-1984[7]. these tests were pluperfect in engineering college-al qadisiyah university lab. 2.2.4. mineral admixture the mineral admixtures is use to improve the mechanical properties of concrete for example workability, strength and durability which are utilized as a replacement ratio to cement in concrete mixture. these admixtures are very fine ground materials' solid and chemically it's be effectively with cement's hydrating to create a modified paste microstructure. silica fume (sf) is a kind of mineral admixtures which was utilized in this study. it’s very fine produced noncrystalline silicate in furnaces of electric arc as a byproduct of the manufacture of elemental silicon as (aci116r-2000)[8] characterized. it is typically classified as associated cementitious materials. cementitious materials referred to materials that are utilized in concrete's mixes in addendum to cement's portland. sf is spherical in shape and is about one hundred times less than the average cement's particle with an average diameter[9]. from trail mixes, (sika fume s92d) was used in this investigation as additive with a ratio (8%) by weight of cement. the chemical composition of silica fume utilized in this study and requirements of physical. 2.2.5. chemical admixtures in order to improvement built up times and reduce the required water/cement ratio of mixes of concrete, this type of admixtures involved all series of the chemicals' soluble are added to the mixes. two types of chemical admixture [10] are used in this study represented by: high performance concrete superplasticizer named (ultrabond sbr500–sbr bonding agent – high performance water resistant bonding agent and admixture for concrete and cement mixes). 1. hpc superplasticiser depended upon improved polycarboxylic ether called (glenium54). 2. high water reduction, high workability without segregation or bleeding, coupled with high early strengths and improves other mechanical properties of concrete have a main positive effect on the applications. the normal mouthful for glenium54 is between (0.5-2.5) liters / 100kg cement or cementitious materials and the normal dosage for sbr is between (0.8-2.3) liters/100 kg cement or cementitious materials. in this study, from trail mixes it used (1.6liters/100kg cementitious materials for sbr and (0.9 liters/100 kg of cementitious materials for glenium54. 2.2.6. mixing and curing water water of concrete mixing must be clean from all harmful substances such as organic materials, salt….. etc., which that cause deleterious of concrete and steel reinforcement. in this investigation, tap water has been used for curing and mixing for all concrete specimens. 2.2.7. steel reinforcement deformed bar of size (ø6mm) was used to reinforced the concrete deck slab in two directions. three specimens of steel bar reinforcement were tested[11] under tensile force by using universal machine in the laboratory of engineering college\al-qadisiyah university. the mechanical steel reinforcement specifications are agreed with astm a615-86. the results of tests that obtained for the yield stresses, and the ultimate stresses at fracture are arranged in table(2). al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 343 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table(2) specifications of used reinforcement nominal diameter (mm) measured diameter (mm) weight (kg/m) yield stress fsy (mpa) ultimate strength fsu (mpa) 6 5.8 5.8 0.22 0.22 449.6 432 683.6 680.5 5.8 0.22 423.9 672.3 5.8 0.22 422.5 685.7 8 7.9 0.37 506.2 627.8 2.2.8. steel plate while build up (i-section) steel plate girder symmetrical and unsymmetrical section with various plates' thickness (6mm for flanges and (3mm for web) was adopted in this study, tensile tests were done by using universal machine in the laboratory of engineering college\al-qadisiyah university. the results of tests that obtained for the yield stresses, and the ultimate stresses at fracture are arranged in table(3). table(3) mechanical properties of used steel plate nominal plate thickness (mm) measured plate thickness (mm) weight (kg/m 2 ) yield stress fsy (mpa) ultimate strength fsu (mpa) 3 3 19.7 143.3 285.6 6 5.8 31.5 122.7 244.4 2.3. loading procedure all specimens are tested under two points load applied out of girder supported plane (i.e. with eccentricity from center of girder) where bending and torsion moments will be developed in this loading condition, see figure(2). practically, in this loading test for both composite and non-composite section, a steel plate arm are made from the same properties of steel plate girder and welded at the point load to prevent local failure in concrete deck slab and to transfer the forces to the steel girder, see plate(1). at each increment load, deflection and marked buckling, the cracks and the load value at each crack are written. the test terminated when it noticed a loading drop, and the girder showed large deflection i.e. failure occurred. when the girder reached the failure point, the load removed, and then recorded of load failure and the cracks are marked on specimens. figure(2) adopted loaded out of supported plane test al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 344 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (a) non-composite girder (b) composite girder plate(1) adopted steel arm to generate torsional moment 2.4. support conditions while the specimens be under combined effect bending and torsion moments, the girder support conditions for this loading test is placed as a simple supports in planes (xy and yz), i.e. simply supported beam to resist bending deformation (uy=0) at both ends and lateral simply supported also (ux=0) at lateral both ends to resist the torsional moment that developed due to loading condition in supports, see figure(3). figure(3) adopted support conditions 3. experimental results six composite and noncomposite specimens have a symmetrical and unsymmetrical steel plate girders (i-section) with (2000mm) span were loaded out of supported plane until failure to be under effect of combined bending and torsion moments. the main aimed of this study to show the effect of composite action of concrete deck slab on unsymmetrical steel plate girder under combined moments and to show the contribution value of concrete deck slab on the ultimate strength. these girders were supported as a torsional simply supported beam i.e., the ends were simply supported with respect to torsional and bending restrains. load deflection relationship, failure pattern, and deflected shape are recorded and discussed in the following. arm arm z y x uy=ux=0 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 345 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3.1. load deflection relationship and failure pattern 3.1.1. noncomposite steel plate girder deflections at mid span and under load (third span) were gaged at each loading incremental for each specimen. figures(4a, b and c) are showing the load-deflection relationship of each specimen (nc.s.w3.bt), (nc.us1.w3.bt) and (nc.us2.w3.bt), respectively. (a) specimen (nc.s.w3.bt) (b) specimen (nc.us1.w3.bt) (c) specimen (nc.us2.w3.bt) figure(4) load-deflection relationship of non-composite specimens from load-deflection curve above, it can be noted that the relationship is approximately linear up to the first yield load and then it becomes nonlinear i.e. inelastic deformation continued and slope of loaddeflection relationship of specimen began to decrease until failure. the ultimate load of unsymmetrical steel plate girders (nc.us1.w3.bt and nc.us2.w3.bt) decreasing by a ratio (30.77% and 46.15%) respectively than ultimate load of symmetrical steel plate girder (nc.s.w3.bt) with decreasing compression flange width (bft) and increasing tension flange width (bfb) this is due to drooping centroid position of section due to decrease compression flange width. table(4) shows 1st buckling load, load at ultimate stage and deflection at midspan of noncomposite specimens. the failure of the adopted steel plate girders (nc.s.w3.bt), (nc.us1.w3.bt) and (nc.us2.w3.bt) were shown in plates(2a, b and c), respectively. it can be noticed that deformed shape, diagonal web buckling and yielding in the top flange of specimen at loading arm which was occur in all specimens at ultimate load. the failure mechanism of all specimens have the same behavior where the plate girder showed initially elastic behavior and diagonal web buckling noticed and happened in all web panels approximately at the same time. as increased load, the top flange at the loading arm was yielding led to al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 346 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. collapse failure. it observed that in all specimens, top and bottom flanges of girder rotates and don't stay in their plane after failure collapse due to applied torsion moment. table(4) load at ultimate stages and midspan deflection of noncomposite girders specimen (d/t) 1st buckling load (kn) ultimate load (kn) midspan deflection (mm) buckling load ultimate load nc.s.w3.bt 116.67 50 92.95 3.36 9.21 nc.us1.w3.bt 116.67 57 64.35 3.7 5.7 nc.us2.w3.bt 116.67 47 50.1 5.91 5.91 3.1.2. composite steel plate girder load deflection relationship, failure pattern, and deflected shape, are recorded and discussed in the following. figures(5a, b and c) explain the load deflection relationship of the adopted specimens (c.s.w3.bt.p), (c.us1.w3.bt.p) and (c.us2.w3.bt.p) and table(5) below show the ultimate load of each specimen and other results. the results showed th.at ultimate strength of composite unsymmetrical steel plate girders (c.us1.w3.bt.p and c.us2.w3.bt.p) increased by increased bottom flange width by a ratio (14.9% and 20%) respectively than symmetrical section (c.s.w3.bt.p) so as to for deflection which increased by a ratio (7.14% and 26.4%) frequently. (a) specimen (c.s.w3.bt.p) (b) specimen (c.us1.w3.bt.p) (c) specimen (c.us2.w3.bt.p) figure(5) load-deflection relationship of composite specimens al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 347 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table(5) the load at ultimate stage and midspan deflection of group(2.1) specimens specimen (d/t) 1st cracking load (kn) ultimate load (kn) midspan deflection (mm) cracking load ultimate load c.s.w3.bt.p 116.67 71.5 143 3.01 6.58 c.us1.w3.bt.p 116.67 71.5 164.5 2.35 7.05 c.us2.w3.bt.p 116.67 78.65 171.6 2.42 8.32 in general, all specimens have the same behavior up to collapse. from load/deflection curve, it is observed that the response of composite plate girders to load is linear at initial stages. the nonlinear behavior of load/deflection is seen after concrete cracking, steel yielding represented by buckling. it is also watched that reduction in stiffness and strength of composite girders lead to an increase in the load. while loading is increased, it is led to the total collapse of the girder. in all specimens, it observed that no separation took place neither for partial bond interaction nor the complete bond interaction between top flange of plate girder and the deck slab of concrete that means full composite action. plates(3a, b and c) showed failure of composite steel plate girder and crack pattern of concrete deck slab of specimens (c.s.w3.bt.p), (c.us1.w3.bt.p) and (c.us2.w3.bt.p), respectively. the failure mechanism is represented by appears diagonal cracks in the top face of concrete deck slab firstly when loading reach to cracking load where these cracks appears between the point load due to tension stressed that generated from torsional moment. as loading increase the diagonal cracks increase and appear longitudinal crack along shear connectors. finally, composite girder may be failure either by deck slab concrete or web bucking then collapse which depends on web's stiffness. (a) specimen (nc.s.w3.bt) plate(2) failure of non-composite specimens yielding in compression flange out of plane deformation web buckling al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 348 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (b) specimen (nc.us1.w3.bt) (c) specimen (nc.us2.w3.bt) plate(2) failure of non-composite specimens (continued) 3.2. effect of concrete slab composite action it is important to know the concrete deck slab's effect in unsymmetrical composite section on ultimate load under combined bending and torsion moments. in experimental work, both composite and noncomposite symmetrical and unsymmetrical steel plate girder were tested under combined effect of bending and torsion, figure(6) show the load deflection relationship between composite and non-composite plate girders. from experimental results, table(6) show the effect of concrete deck slab on composite plate girder behavior and it is observed that the concrete deck slab contributes in increasing ultimate load by a ratio (53.85)% for symmetrical section and (155.63 – 242.51)% for unsymmetrical section. it is also seen that the contribution value of concrete deck slab increased in unsymmetrical section than symmetrical section. yielding in compression flange out of plane deformation yielding in compression flange out of plane deformation web buckling web buckling al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 349 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (a) specimen (s.w3.bt.p) (b) specimen (us1.w3.bt.p) (c) specimen (us2.w3.bt.p) figure(6) effect of composite action on girder's behavior table(6) effect of concrete deck slab in composite girder specimen ultimate load (kn) difference (%) = (c nc)/nc non-composite (nc) composite (c) s.w3.bt.p 92.95 143 53.85 us1.w3.bt.p 64.35 164.5 155.63 us2.w3.bt.p 50.1 171.6 242.51 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 350 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (a) specimen (c.s.w3.bt.p) (b) specimen (c.us1.w3.bt.p) (c) specimen (c.us2.w3.bt.p) plate(3) failure of composite steel plate girder and crack pattern of concrete deck slab 4. conclusions 1. the concrete slab contributes in increasing the ultimate load of composite section by a ratio (53.85)% for symmetrical section and (155.63 – 242.51)% for unsymmetrical section when the composite girder under loaded out of supported plane. 2. the contribution value of concrete slab in composite plate girder increased in unsymmetrical section than symmetrical section this is due to the ideal use of materials, i.e. founded of concrete slab in compression zone required the benefit from that case to reduce the compression flange and increase the tension flange. 3. in addition to the improvement of strength capacity of steel plate girder by concrete slab in composite section, the concrete slab in composite section provides a restrained for the compression flange and prevents flange from warping due to torsion while the tension flange warped freely due to warping torsion effect. local failure diagonal cracks diagonal cracks diagonal cracks longitudinal cracks longitudinal cracks longitudinal cracks al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 351 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. references 1. segui w. t., steel design, fourth edition, 2007. 2. salmon c. g., johnson, j. e. and malhas f. a., steel structures, fifth edition, 2009. 3. baskar k., shanmugam n., and thevendran v., finite-element analysis of steel– concrete composite plate girder, journal of structural engineering, 2002. 4. aci committee 318, building code requirements for structural concrete (aci 318m-12) and commentary (aci318rm-12), american concrete institute, detroit, u.s.a., 2012. 5. aisc, torsional analysis of structural steel members, american institute of steel construction inc., usa, second edition, 2003. 6. iraqi specification, no.5/1984, portland cement,الجهاز المركزي للتقييس والسيطرة النوعية ,وزارة التخطيط 7. iraqi specification, no. 45/1984, aggregate from natural sources for concrete and construction, الجهاز المركزي للتقييس والسيطرة النوعية. ,وزارة التخطيط 8. aci 116r-00, cement and concrete technology, aci committee 116, usa, 2000. 9. kosmatka, s. h., kerkhoff, b., and panarese, w. c., design and control of concrete mixtures, portland cement association, skokie, il, 2008. 10. astm c494-99,chemical admixture for concrete, annual book of astm standards american society for testing and materials, vol.04-02, 1999, pp. 245-252. 11. astm-a370, standard methods and definitions for mechanical testing of steel products, aashto no.: t244, 1977. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 872 computational modeling of turbulent flow around airfoil using different turbulence models asst. lecturer hakim tarteeb kadhim mechanical department al_dewaniyah technical institute email: eng.hakim84@yahoo.com received 4 jun 2013 accepted 16 july 2014 abstruct the analysis of the two dimensional subsonic flow over a national advisory committee for aeronautics (naca) 0015 airfoil at two angles of attack, (α= 0°, α= 16°) and operating at a reynolds number of 4.4 x 10 5 is presented. the flow was obtained by solving the steady-state governing equations of continuity and momentum conservation combined with one of three turbulence models [spalart-allmaras, realizable and shear stress transport (sst)] aiming to the validation of these models through the comparison of the predictions and the free field experimental measurements for the selected airfoil. the aim of the work was to show the behavior of the airfoil at these conditions and to establish a verified solution method. attention is focused on determination of the pressure distribution around the airfoil. simulations were performed on an map quadratic structured grid with the fluent (v6.3) software package which solves the navier–stokes equations by using finite volume methods. calculations were done for constant air velocity altering only the angle of attack for every turbulence model tested. calculations showed that the turbulence models used in commercial cfd codes do not give yet accurate results at high angles of attack and show that the realizable k- model gave the most closness prediction of pressure distribution when compared with the experimental data [1]. نمذجة حسابية لجريان مضطرب حول مقطع جناح بأستخدام نماذج اضطراب مختلفة م.م حاكم ترتيب كاظم /الديوانية قسم الميكانيك المعهد التقني– الخالصة : لزوايا هجوم (naca 0015)قدم هذا البحث تحليل لجريان ثنائي األبعاد دون سرعة الصوت لمقطع جناح من نوع (α= 0°, α=16°), (4.4)لعدد رينولدز x 10 5 . الجريان تضمن حل المعادالت الحاكمة لالستمرارية وحفظ الزخم للحالة spalart-allmaras, realizable and shear stress)) المستقره والمتوفره في كل من النماذج المستخدمه في البحث transport sst تم في هذه النتائج المستحصلة مع البيانات التجريبية.ل مقارنة لغرض اختبار صالحية هذه النماذج من خال الدراسة بيان سلوك مقطع الجناح وتثبيت طريقة حل عند هذه الظروف. وكذلك اهتمام رئيسي لتحديد توزيع الضغط حول (quadratic)ألضالع مقطع الجناح. تم اجراء المحاكاة على شبكة مبنية بشكل منتظم , نوع العنصر المستخدم فيها رباعي ا ستوك بواسطة استخدام طريقة الحجوم المحدودة -( الذي يحل معادالت نافيرfluent v6.3مع استخدام برنامج الحاسوب ) (finite volumes) تم تثبيت سرعة الجريان وتغير زوايا الهجوم لكل نموذج اضطراب.النتائج بينت بأن النماذج . mailto:eng.hakim84@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 872 بأن المقارنة بين النتائج النظرية والعملية ال تعطي نتائج دقيقه عند زوايا الهجوم العاليه. وكذلك بينت المستخدمه في البرامج التجاريه .[1]يتنبأ توزيع معامالت ضغط مقاربة للنتائج العملية (realizable k-) نموذج االضطراب nomenclatur  : density (kg/ m 3 ) u : velocity component in x direction (m/s) v : velocity component in y direction (m/s) re : reynolds number x axial coordinate in the physical domain c : cord, (m) cp: coefficient of pressure x & y; coordinate direction abbreviations cfd: computational fluid dynamics rans: reynolds average navier-stokes equation sst: shear stress transport s-a: spalart-allmaras naca: national advisory committee for aeronautics introduction simulation of the turbulent flow field around airfoil sections is an up to date problem. many phenomena occur in the flow passing a real airfoil section, such as the transition from the laminar to turbulent region, laminar or turbulent separation, and reattachment of separated flow, etc. this makes this problem complex and difficult to solve numerically. it is important to see how these airfoils can be computationally modelled and what sorts of models produce the most accurate results, in comparison to experimental data [2]. in industrial cfd applications, rans modelling remains one of the main approaches when dealing with turbulent flows. over decades, this has consequently facilitated the development of a great variety of rans turbulence models. modelling approaches in the context of rans have shown different degrees of success in various engineering applications, spanning from mixinglength models, linear and nonlinear eddy viscosity models to algebraic and differential reynolds stress models with a hierarchy of increasing complexity in the modelling formulation and related cfd implementations [3]. two-equation turbulence models or competitive one-equation models, are considered to be the minimum level of closure in navier–stokes solution methods that are capable to cope with complex flows. two-equation eddy-viscosity models have been credited certain advantages, mostly related to their simplicity and their superior numerical properties, compared to other more sophisticated models, like those based on reynolds stress closures. in their conventional forms, two-equation models often yield poor predictions for flows that encounter adverse pressure gradients, curvature, rotation or complex strain fields. in order to overcome these deficiencies, without resorting to more sophisticated and more expensive turbulence models, various modifications have been proposed in the literature [4]. among them, those employed in the present method. working even with two-equation models, the low-reynolds terms which are activated close to solid walls are a source of convergence difficulties. for structured grids, a series of papers al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 addressed, in the past, the practical implementation of these models and delineated achievements or suggestions to improve their numerical behavior. in addition, practical problems about how to approximate distances from solid walls or how to compute derivatives normal to the wall are readily solvable on structured grids, with both precision and simplicity. in contrast, the relevant approaches for unstructured grids with triangular elements are, by no means, trivial; they often suffer from ambiguities or lack of precision during the treatment of the corresponding terms [5, 6]. the aim of the present work is to investigate the effect of several turbulent models, available in the commercial code fluent (v6.3), on the pressure coefficient distribution around the naca 0015 airfoil at two angles of attack, (α= 0°, α= 16°) and existing experimental data from [1], are performed to validate the computational results. the velocity distribution with the realizable k-ɛ turbulence model at (α= 0°, α= 16°) will also be found. governing equations for all flows, the solver solves conservation equations for mass and momentum. additional transport equations are also solved when the flow is turbulent. the equation for conservation of mass or continuity equation, can be written as follows[7],: m su t p    )(.   (1) equation (1) is the general form of the mass conservation equation which valid for incompressible as well as compressible flows. the source m s is the mass added to the continuous phase from the dispersed second phase (for example, due to vaporization of liquid droplets) and any user-defined sources. conservation of momentum in an inertial reference frame is described by equation (2) fgpuuu t       )(.)(.)( (2) where p is the static pressure,   is the stress tensor (described below) and g   and f  are the gravitational body force and external body forces (for example, that arise from interaction with the dispersed phase), respectively. f  also contains other model-dependent source terms such as porous-media and user-defined sources. the stress tensor is given by:   iuuu t  . 3 2          (3) where  is the molecular viscosity, i is the unit tensor, and the second term on the right hand side is the effect of volume dilation. for the 2-d, steady and incompressible flow the continuity equation is: al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 0      y v x u (4) momentum equations for viscous flow in x and y directions are, respectively: x yxxx f yxx p dt du              (5) y yyxy f yxy p dt dv              (6) where due to characteristics of the 2-d flow in continuity equation the term z y   and in momentum equation, z zx   and z zy   drop out. the flow was obtained by solving the governing equations of continuity and momentum conservation combined with one of three turbulence models. computational method in this paper, the naca 0015, the well documented airfoil from the 4-digit series of naca airfoils, was utilized. the naca 0015 airfoil is symmetrical; the 00 indicates that it has no camber. the 15 indicates that the airfoil has a 15% thickness to chord length ratio; it is 15% as thick as it is long. reynolds number for the simulations was 4.4 x 10 5 , same with the reliable experimental data from[1], in order to validate the present simulation. the free stream temperature is 300 k, which is the same as the environmental temperature. the density of the air at the given temperature is ρ=1.225 kg/ m 3 and the viscosity is μ=1.7894×10 -5 kg/ms. for this reynolds number, the flow can be described as incompressible. this is an assumption close to reality and it is not necessary to resolve the energy equation. a segregated, implicit solver was utilized (ansys fluent 6.3.26., 2006) calculations were done at two angles of attack (α= 0°, α= 16°). the airfoil was modelled in the software package gambit (2.4.6). the geometry of the airfoil was imported, from an airfoils [8], and a c-shaped mesh created. the large distance of the domain boundary from the airfoil, in comparison to the airfoil chord length, was so that the boundary conditions had minimal influence on the flow field in the vicinity of the airfoil and allowed the boundary conditions to be simplified [9]. this domain, shown in figure (1). a fine mesh was needed in the vicinity of the airfoil in order to model the flow field accurately. in the vicinity of the airfoil it was necessary to refine the mesh at the trailing edge in order to ensure accurate modelling, as this would be where events of interest would occur. it was important to maintain good aspect ratios of cells across the domain as well as maintaining smooth changes in cell size, thus quadrilateral elements were used. figure (2) shows the computational domain and the mesh that was used to solve the problem. figure (3) shows the mesh around the airfoil. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 828 turbulance models the inlet boundary velocity u, was set to 35 m/sec for all turbulence models for direct comparison with the experimental result [1]. the corresponding reynolds number is 4.4 x 10 5 based on the chord c of the airfoil (180 mm). a computational grid of 15100 cells was fixed for all models. three different turbulence models were used, two equation models such as realizable and sst k- model and spalart-allmaras model. these models selected because they are most widely used in aerodynamic industry, and they have well documented strength. also these models proved to have a superior performance for flows involving strong streamline curvature [10]. all computations have been performed on the same grid to ensure that the presented solution for each model will be compared with each other. flow conditions around the airfoil were built up by finite volume analysis using fluent 6.3 software. results and discussion simulations for two angles of attack were done in order to be able to compare the results from the different turbulence models and then validate them with existing experimental data from [1]. to do so, the model was solved at zero angle of attack and high angle of attack, α= 16°. turbulence models are often judged for accuracy based on the comparison of their predictions with the experimentally observed values. figure (4) shows the variation in the pressure coefficient around the airfoil, for each model and experimental data, at zero degrees angle of attack. the experimental results showed scattered values upon the numerical pressure coefficient. turbulence models predictions are very close to each other and all it predict high pressure coefficients values at the nose and slightly high pressure coefficients values for the residual part of airfoil when compared with experimental values. figure (5) shows the variation of the pressure coefficient along the lower surface of the airfoil at angle of attack, α= 16°. all turbulence models predict high pressure coefficients at the nose and low pressure coefficients values for the residual part of airfoil when compared with experimental values and all models show a unsimilar profile behavior between them. figure (6) shows the variation of the pressure coefficient along the upper surface of the airfoil at angle of attack, α= 16°. also the experimental results showed scattered values upon the numerical pressure coefficient. the s-a and sst k-ω predictions are very close to each other and their prediction is not acceptable with the experimental data r k-ε model predict close values to experimental data when compared with the other turbulence models. for two angles of attack (α= 0°, α= 16°) the realizable k-ε model gave the most closeness prediction of pressure distribution when compared with the experimental data for both suction and pressure sides. figures (7) and (8) show the simulation outcomes of static pressure at angles of attack 0° and 16°with the realizable k-ε turbulence model. the pressure on the lower surface of the airfoil was greater than that of the incoming flow stream and as a result it effectively “pushed” the airfoil upward, normal to the incoming flow stream. on the other hand, the components of the pressure distribution parallel to the incoming flow stream tended to slow the velocity of the incoming flow relative to the airfoil, as do the viscous stresses. contours of velocity magnitude at angles of attack (α= 0°, α= 16°) are also shown in figure (9) and (10). at zero angle of attack the velocity distribution is symmetric where the naca 0015 airfoil is symmetrical while at sixteen angle of attack, the upper surface of the airfoil experienced a higher velocity compared to the lower surface until the separation point where the velocity al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 828 equal zero. velocity vectors of the flow field around airfoil for different turbulence models are presented in figure (11). the sst k-ω model and s-a model predict very early separation with regard to r k-ε model. that was expected from the pressure distribution where the wall shear stresses occurred on airfoil gave an idea about the flow separation. conclousion this paper showed the behavior of the 4-digit symmetric airfoil naca 0015 at two angles of attack. the most appropriate turbulence model for these simulations was the realizable k-ɛ two equation model, which had the most closeness prediction of pressure distribution when compared with the experimental data for both suction and pressure sides. turbulence models predictions are very close to each other at zero degrees angle of attack while at high angle of attack, α= 16° the numerical pressure coefficient distributions showed scattered values upon the experimental results. in summary it can be said that the major error in the three turbulence models used for two angles of attack, is at the leading edge. this is apparent from the analysis of the pressure coefficient distribution around the airfoil. reference [1] ahmed, obaid “study of aerodynamic characteristics of an airfoil with bumps”, m.sc. thesis, department of machines and equipments, university of technology, 2009. [2] hills, j. l., “numerical modeling of turbulent flow past an airfoil”, pp.1-10, april, 2005. [3]shia-hui, peng. and peter, eliasson. “examination of the shear stress transport assumption with a low-reynolds number k − ω model for aerodynamic flows”, chalmers university of technology, se-412 96 gothenburg, sweden, 2009. [4] d.g. koubogiannis. a.n. athanasiadis. and k.c. giannakoglou “oneand two-equation turbulence models for the prediction of complex cascade flows using unstructured grids”, laboratory of thermal turbomachines, national technical university of athens, p.o. box 64069, 15710 athens, greece,2001. [5] barth tj. “aspects of unstructured grids and finite-volume solvers for the euler and navier– stokes equations”, agard report 787. special course on unstructured grid methods for advection dominated flows, 1992. [6] farhat c. and lanteri s. “simulation of compressible viscous flows on a variety of mpps: computational algorithms for unstructured dynamic meshes and performance results” comp meth appl mech engng 94;119:35–60. [7] douvi c. e., tsavalos i. a., and margaris p. d., “evaluation of the turbulence models for the simulation of the flow over a national advisory committee for aeronautics (naca) 0012 airfoil”, journal of mechanical engineering research vol. 4(3), pp. 100-111, march 2012. [8] abbtt, i.h. and von doenhoff, a.e. “theory of wing sections”, dover publications, inc. 1959. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 [9] baxevanou, c.a., and fidaros, d.k., “validation of numerical schemes and turbulence models combinations for transient flow around airfoil”, engineering applications of computational fluid mechanics vol. 2, no. 2, pp. 208–221 , 2008. [10] omar badran, regis quadros and fettah aldudak, “two-equation turbulence models for turbulent flow over a naca 4412 airfoil at angle of attack 15 degree”, p.p 1-8, 2003. figure (1): geometry of the model, where c = chord length of the airfoil figure 3 – computational domain figure (2): computational domain al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 figure (3) mesh around the airfoil figure (4) variation of pressure coefficient around airfoil at zero degrees angle of attack al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 figure (5): variation of the pressure coefficient along the lower surface of the airfoil at 16° angle of attack. figure (6): variation of the pressure coefficient along the upper surface of the airfoil at 16° angle of attack. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 827 figure (7): contours of static pressure at zero angle of attack with the realizable k-ɛ turbulence model. figure (8): contours of static pressure at 16° angle of attack with the realizable k-ɛ turbulence model. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 figure (9): contours of velocity magnitude at zero angle of attack with the realizable k-ɛ turbulence model. figure (10): contours of velocity magnitude at 16° angle of attack with the realizable k-ɛ turbulence model. al-qadisiya journal for engineering sciences, vol. 7……no. 3 ….2014 822 figure (11): distribution of velocity vector around airfoil with different turbulence models al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 951 studying the corrosion resistance of anodized low carbon steel in alkaline solution sami a.ajeel production & metallurgy dept. university of technology-baghdad-iraq samiabualnon2@yahoo.com, 07713014752 received 2 november 2014 accepted 23 december 2014 abstract low carbon steels are widely used materials in industrial application due to its availability and properties. therefore it always needs to improve its properties especially corrosion resistance. one of the most important methods for improving its corrosion resistance is anodizing process. this study involves anodized of low carbon steels in 1 m sodium hydroxide (alkaline) electrolyte for 30 minute, using constant current technique at a range of (20-620) ma/cm 2 . atomic force microscope (afm) used to investigate the topography and anodic film parameters, it was found that the roughness of the anodic film is mainly depend on the anodizing current density and its increase from 0.9 (as polished) to (0.281-0.598) nm after anodizing. coating thickness also increases with an increase in current density supply to the range of (2.5-13.3) µm. the corrosion behaviors of anodized and non-anodized of low carbon steel specimens in sea water are obtained. the corrosion current density and corrosion rate are decreased with an increase in anodic current density which increases anodic film thickness. key words: anodizing, low carbon steel, constant current, polarization, corrosion. الخالصة لذلك تبرز حاجة دائمية لتحسين خواصه يستخدم الصلب الكاربوني بشكل واسع في التطبيقات الصناعية لوفرته وخواصه الجيدة، لدراسة انودة الصلب وخاصة خواص التآكل. احد الطرق المهمة لتحسين مقاومة التآكل هي عملية األنودة حيث تتضمن هذه ا 003-03دقيقة بأستخدام تقنية التيار الثابت بمدى 03الكاربوني في مول واحد من محلول هيدروكسيد الصوديوم بزمن قدره ير/سمامب 0 . طبقة األنودة تعتمد بصورة رئيسية ( لدراسة طبوغرافية سطح األنودة، لقد وجد بأن خشونة afmتم استخدام جهاز القوة الذرية ) ( بعد األنودة. سمك التغطية يزداد كذلك (nm 0.598للمعدن الصقيل( الى nm 0.09) على كثافة تيار األنودة حيث تزداد من . تم الحصول على سلوك التآكل للصلب الكاربوني قبل وبعد عملية األنودة (µm 13.3التيار المسلط الى )مع الزيادة في كثافة بأختالف تيار التآكل حيث تم مالحظة ان معدل التآكل يتناقص مع زيادة كثافة التيار الذي بدوره يزيد من سمك طبقة األنودة. introduction low carbon steel is a low cost material with easy availability and excellent physical properties, these properties make it one of the best preferred materials for industry applications [1, 2]. the use of carbon steel means potential hazards are presented due to internal corrosion damage from aqueous produced fluids that contain acidic gases, carbon dioxide, and hydrogen sulfide [3]. mailto:samiabualnon2@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 the oxide film formed in passivation usually has a denser structure and higher chemical stability than bulk iron, therefore tends to mitigate further iron oxidation by preventing the direct contact between bulk iron and oxygen, hydroxyls and/or water molecules. therefore, the multi-layer iron oxide film on steel surface is commonly referred to as the "protective layer" to reduce corrosion rate [5, 6]. carbon flakes or nodules in iron or steel with high carbon content may cause an electrolytic potential and interfere with coating or platting ferrous metals are commonly anodized electrolytically in nitric acid, or by treatment with red fuming nitric acid, to form hard black ferric oxide. this oxide remains conformed even when plated on wire and the wire is bent [2]. the anodic film thus formed is composed of a compact inner layer and a porous outer layer and due to this porous structure; anodic film is susceptible to aggressive environments [7]. burleigh et al. [8] investigated anodized steel in koh solution to create an oxide layer on the surface of steel by using constant voltage technique, they found that at higher voltage and temperature, a semiadherent dichromic oxide is formed on the surface. the adherent oxide may be grown from nano to several microns thick on low carbon steel. these anodized film provide improved corrosion protection for steel and these are also suitable substrates for the bonding of organic coatings. the aim of this work is to investigate the formation of anodic oxide film for low carbon steel by means of sodium hydroxide (as alkaline electrolyte) anodizing process with constant current; in terms of applied current, in order to study the effect of anodic coating on corrosion resistance. experimental a sheet of low carbon steel with the chemical composition indicated in table 1 was cut into specimens of dimensions of 2 cm× 2cm × 0.4cm. the surface of the alloy was ground using emery paper up to 1000 grit to produce a reasonably flat surface. due to the very small depth of the field obtained from an optical microscope, it is essential that the surface is flat; in fact it needs to be optically flat acting as a perfect mirror. the specimen therefore has to be polished with 0.5 μm diamond paste. the specimens were carefully cleaned with water, rinsed with acetone and dried under air. figure 1 shows a typical microstructure of low carbon steel specimen of large ferrite phases as white areas and pearlite phases as dark areas. analysis of these specimens was carried out using (spark technique) in (dc power supply rxn-3020d electronics co, ltd) as shown in table 1 .stainless steel sheet type 316 with dimensions of (7x11x1 mm) was used as cathode. to prepare anodized specimens, the specimens were ground in progressively fine silica water proof papers with grade of 120, 250, 350, 500, 1000 and 1200 grit. to remove the cold work from cutting and dust, grinding is carried out by hand; the specimen is rotated 90°and washing by distilled water between each step .after grinding, the specimens are finally polished using fine abrasives which have 1 micron diamond as a paste on red felt cloth. the low carbon steel strip sample was connected to the positive terminal where it becomes (anode) while the stainless steel strip was connected to the negative terminal to be (cathode). the steel object and counter electrode are immersed in a solution of 1 mole naoh in the anodizing vessel. digital multimeter type (victor 98 a) interface is connected to the desktop computer and power supply applying current density across the terminals to anodize the steel object by growing anodic oxidation film directly on a steel surface of the object. the power supply is switched on in which current density increased gradually. before the power supply is switched off, anode specimen is removed from anodizing cell immediately to prevent the dissolution of anodic film, then it's rinsed with running distilled water to remove the excess solution on the specimen. the sealing process is used when the anodizing process is completed, the al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 969 specimen is dipped in a flask filled with hot distilled water and kept for 20 minutes at 98 ±1 oc to seal porous anodic film, and the specimens are drying at 60oc for 30 minutes. afm (atomic force microscope) was utilized for surface characterization of porous anodic oxide film like porosity and roughness. the polarization was carried out in a 1-liter beaker consisting of working, counter and reference electrodes. the working electrode was anodized and non-anodized carbon steel alloy, held by steel jigs designed to hold the specimens, it was covered with shrinkage tube to provide the bad contact and hold it stable in the cell. the counter electrode was a pank type mlab 200 seated directly opposite to the working electrode.the reference electrode was a standard calomel electrode (sce) bridged by a laggin-haber probe. the distance between the electrode surface and the lagginhaber capillary was set at about the optimum value of 1 mm to minimize the experimental error due to ir drop; the polarization began below the corrosion potential about 250mv in cathodic region and then increased with sweep rate of 10 mv/ min. to the anodic region potentials. a thermometer was used to maintain the solution temperature within  1oc at room temperature. the corrosion current density is measured from polarization curve in order to use in corrosion rates calculations. corrosion rates are calculated using the following relationship (9) ( ) (1) where: icorr : corrosion current, μa e.w.: equivalent weight of the specimen (28 g. / equivalent). ρ: density of specimen (7.81 g./ cm 3 ) . results and discussions anodized low carbon steel electrochemical anodizing was performed in 100 ml 1n naoh by applying constant current density technique to get the response voltage against time. the appearance of the anodic oxide on low carbon steel sheet is related to the applied current densities. the electrolyte is contained one mole sodium hydroxide. figure 2 shows the response voltage with time at different applied constant current densities as shown in table 2. the voltage tends to increase suddenly with anodizing time. initially, anodic voltage values increase quickly with time then a voltage tendency to the steady – state value is distinguished for all cases in the range of 2.2 to 6.6 voltages. the steady state voltage reached in very short time which decreases with an increase in applied current density as shown in figure 1. coating thickness was measured using eddy current testing method (coating thickness gauge tt260 italy made), as shown in table 2, the coating thickness increases with an increase in the current density due to the thick layer that precipitates on the low carbon steel surface. burleigh, et al. [1] indicated that an increase in anodizing voltage leads to increase the rate of growth of anodic film thickness. figure (3) shows the surface roughness of anodic film on low carbon steel, it can be concluded, after anodizing process the average roughness of low carbon steel was in the range of 0.281 to 0.598 nm respective to the applied current density. these values indicate that average roughness increases with an increase in applied current density as shown in table 2. the pore diameters for low carbon steel were measured as listed in table (3). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 the increase in applied current density leads to an increase in anodizing voltage which leads to an increase in growth rate in anodic oxide layer thickness resulting in an increase in surface roughness as shown in table (3). the pore diameter also decreases due to an increase in current density. this can be observed in the gradual increase in applied current density. linear polarization measurements of anodized and non anodized low carbon steel specimens in 3.5% nacl solution are shown in figures (4-11). the polarization curves indicate the general behavior of cathodic and anodic regions. the corrosion potential (ecorr) and corrosion current density (icorr) calculated using the tafel extrapolation method are also given in table (4). it is evident from table (4) that the increase in applied current density for anodized specimens decreases the icorr and corrosion rates. the extent of decrease in icorr and corrosion rates is found to be a function of the anodized applied current density, higher the applied current density, lower the values of corrosion rate and lower icorr values. the corrosion potential increases in the noble direction with the increase in anodizing applied current density. the observed positive shift (noble direction) in ecorr and the decrease in icorr in the presence of anodic oxide layer (table 4) are conserved to be due to the nature of surface anodic oxide films on steel and suggest that the corrosion is under passive region control. it can be concluded from afm results, that the pore size of anodic oxide film decreases with an increase in anodic applied current densities which improve corrosion resistance of low carbon steel as shown in table(4). conclusions: the following conclusions can be drawn from this study: 1the roughness of anodic film increases with increasing anodizing current density. 2the thickness of anodic film increases with increasing anodizing current density. 3the pore diameter of the anodized surface is decreases with an increase in current densities. 4improvement in corrosion resistance is clearly observed for specimens after anodizing process due to increasing the thickness of anodizing layer. 5corrosion current density decreases for anodizing specimens compared with nonanodizing. 6the corrosion potential increases to noble direction due to increase in anodized current densities. references [1] dieter landolt, "corrosion and surface chemistry of metals", a swiss academic publisher distributed by crc press, 2003. [2] sastri v. s., “corrosion prevention and protection practical solutions”, john wiley, 2007. [3] kure k., konno y., tsuji e., skeldon p., thompson g.e., habazaki h .," formation of selforganized nanoporous anodic films on type 304 stainless steel", electrochemistry communications, volume 21, july 2012, pages 1–4. [4] burleigh t. d., dotson t. c., dotson k. t., gabay s. j.,”anodizing steel in koh and naoh solutions”, journal of the electrochemical society, 154 _10_ c579-c586 _2007 http://www.sciencedirect.com/science/article/pii/s138824811200197x http://www.sciencedirect.com/science/article/pii/s138824811200197x http://www.sciencedirect.com/science/article/pii/s138824811200197x http://www.sciencedirect.com/science/article/pii/s138824811200197x http://www.sciencedirect.com/science/article/pii/s138824811200197x http://www.sciencedirect.com/science/article/pii/s138824811200197x http://www.sciencedirect.com/science/journal/13882481 http://www.sciencedirect.com/science/journal/13882481 http://www.sciencedirect.com/science/journal/13882481/21/supp/c al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 [5] hamadou,a. kadri, n.benbrahim,”characterisation of passive film formed on low carbon steel in borate buffer solution”, applied surface science, vol.252, p-1510-1519,2005. [6] mjajid shahzad, michel chaussumier, remy chieragatti, "effect of sealed anodic film on fatique performance of 2214-t6 aluminum alloy", surface and coating technology, vol.206, no.11-12, pp-2733-2739, 2012. [7]singh s.k. , mukhrjee a.k. ,"kinetic of mild steel corrosion in aqueous acetic acid solution", journal of material sciencetechnology, vol.26, no.3, p-264-269, 2010. [8] burleigh t. d., schmuki p., s.virtanen,”properties of the nanoporous anodic oxide electrochemically grown on steel in hot 50% naoh”, journal of the electrochemical society, vol.156 no.1, p-c45-c53, 2009. [9] fontana m.g.,”corrosion engineering”, international student edition, mc graw – hill book com., third edition, 1987. table (1): standard and analytical chemical compositions of low carbon steel alloy. metals iron carbon manganese aluminum copper sulfur phosphorus standard by astm a568 rem. 0.02-0.07 0.35 max 0.035 max 0.030 max analysis by (wt.%) 99.67 0.07 0.21 0.03 0.02 table (2): anodizing voltage and coating thickness at different current densities supply. sample no. current density supply (ma/cm 2 ) voltage v coating thickness µm 0 1 20 2.2 2.5 2 120 3.7 2.7 3 220 4.4 4.7 4 320 4.6 4.8 5 420 6.1 5.3 6 520 6.4 6.5 7 620 6.6 13.3 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 table (3): anodic layer specifications by afm contact mode no current density ma/cm 2 roughness average nm average pore diameter nm pore depth nm as 0.09 1 20 0.281 166.37 0.833 2 120 0.304 165.66 0.882 3 220 0.304 159.82 0.858 4 320 0.383 128.27 1.16 5 420 0.393 101.57 1.18 6 520 0.404 89.47 1.24 7 620 0.598 84.95 1.8 table (4): corrosion rate of anodized carbon steel at different current densities. sample no. current density supply (ma/cm 2 ) icorr. (µa/cm 2 ) ecorr. (mv) corrosion rate (mpy) 0 15.19 -539.5 7.081 1 20 2.12 -359.7 0.988 2 120 2.07 -341.3 0.965 3 220 1.75 -368.8 0.816 4 320 1.19 -351.6 0.555 5 420 1.05 -342.9 0.489 6 520 0.636 -305.9 0.296 7 620 0.376 -279.5 0.175 ferrite pearlite x750 figure (1): microstructure of low carbon steel polished and etched with natal solution for 1 min al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 965 a b c d e f g figure (2): relationship between voltage and time at different current densities: a-20, b120, c-220, d-320, e-420, f-520, g-620 ma/cm 2 . 0 0.5 1 1.5 2 2.5 0 10 20 30 40 0 1 2 3 4 0 10 20 30 40 v o lt a g e v time min. 0 1 2 3 4 5 0 10 20 30 40 v o lt a g e v time min. 0 1 2 3 4 5 0 10 20 30 40 v o lt a g e v time min. 0 2 4 6 8 0 10 20 30 40 v o lt a g e v time min. 0 2 4 6 8 0 10 20 30 40 v o lt a g e v time min. 0 2 4 6 8 0 10 20 30 40 v o lt a g e v time min. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 966 a b c d e al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 f g a b figure (3): afm contact mode for anodized carbon steel at different current densities: a-20, b 120, c-220, d-320, e-420, f-520, g-620 ma/cm 2 , (a) 2d, (b) 3d. figure (4): corrosion behavior of anodized low carbon steel at current density of 20 ma/cm 2 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 figure (5): corrosion behavior of anodized low carbon steel at current density of 120 ma/cm 2 figure (6): corrosion behavior of anodized low carbon steel at current density of 220 ma/cm 2 . figure (7): corrosion behavior of anodized low carbon steel at current density of 320 ma/cm 2. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 961 figure (8): corrosion behavior of anodized low carbon steel at current density of 420 ma/cm 2 . figure (9): corrosion behavior of anodized low carbon steel at current density of 520 ma/cm 2 . al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 911 figure (10): corrosion behavior of anodized low carbon steel at current density of 620 ma/cm 2 . figure (11): corrosion behavior of low carbon steel before anodizing. microsoft word 2.doc ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٤ دراسة بعض الخواص الميكانيكية لمادة مركبة بوليميرية مقواة باأللياف علي إبراهيم الموسوي بابل-المعهد التقني مدرس مساعد الخالصة إن الهدف من هذا البحث هو دراسة تأثير تغيير نسبة التقوية باأللياف على الخواص الميكانيكية للمادة المركبة المكونة من راتـنج 340)ذات كثافة سـطحية ) 0°-45°(ية اإلتجاه المقوى بألياف كيفالر بشكل ظفائر محاكة ثنائ(ep-10)اإليبوكسي نوع كونبكسترا g/cm3) وقد شملت هذه الخواص كل من مقاومة الصدمة ، مقاومة الشد ، مقاومة اإلنثناء ، والصالدة حيث تم في البداية إستخراج ية مختلفة من أليـاف كـيفالر الخواص الميكانيكية لراتنج الفينول فورمالدهيد قبل التقوية باأللياف بعدها تم تدعيم الراتنج بنسب وزن و دراسة تأثير ذلك على الخواص المذكورة وكما موضح في المخططات البيانية(%20 ,%40 ,%60) .المادة المركبة ، الخواص الميكانيكية ، راتنج اإليبوكسي كونبكسترا ، ألياف كيفالر : الكلمات الدالة study of some mechanical properties for polymeric composite material reinforced by fibers ali i.al-mosawi technical institute babylon assist. lecturer abstract the objective of this research is to study the effect of changing the reinforcement percentage by fibers on mechanical properties, for composite material consists of conbextra epoxy (ep-10) resin reinforced by biaxial woven roving kevlar fibers )°٠°-٤٥( with density (340 g/cm3) which included impact strength , tensile strength , flexural strength and hardness where the mechanical properties were extracted for phenol formaldehyde resin before reinforcement by fibers, then we reinforced the resin by different weight percentage from kevlar fibers(20%,40%,60%) and studied the effect on the above mechanical properties as illustrated in the diagrams . keywords:-composite material , mechanical properties, conbextra epoxy resin , kevlar fibers . .)introduction(المقدمة عرفتْ تقنية تصنيع المواد المركبة بأبسط صورها منذ قرون عدة حيث إستخدمها البابليون في بناء بيوتهم عن تتكون المادة المركبة من دمج مادتين أو أكثر وتشمل الخالئط . طريق خلط نشارة الخشب بمادة الطين لتقويته (blends) والبالستك )reinforced plastic( إن . ]١٩٩٩،علي[والفيزياوية مختلفتي الخواص الميكانيكية ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٥ على مادة جديدة ذات خواص هندسية وفيزيائية تختلف عن خواص المواد عملية الدمج هذه تؤدي إلى الحصول زيائية لهذه يعتمد اإلستخدام العام للمادة المركبة بشكل كبير على الخواص الميكانيكية والفي .الداخلة في تركيبها المواد لذلك فإن دراسة هذه الخواص تحت تأثير القوى واألحمال في ظروف مختلفة يكتسب أهمية كبيرة لمعرفة يوجد في الطبيعة الكثير من األمثلة على المواد المركبة .مدى مالئمة هذه الخواص لمكان عمل هذه المواد ناعة فإن تقوية الراتنجات باأللياف الصناعية هي األكثر أما في الص. الخشب ومنها ألياف السليلوز مع مادة :و لتصنيع مادة مركبة يجب توفر مادتين هما . إنتشاراً .(matrix material)المادة األساس -١ تكون مواد األساس أما مواد معدنية متكونة من المعادن وسبائكها وتتميز بثقل وزنها ومتانتها العالية أو قد تكون والتي تمتاز بخفة وزنها ومقاومتها المرتفعة لدرجات الحرارة العالية ولكنها ضعيفة المقاومة مواد سيراميكية وهي األكثر إستعماالً وإنتشاراً ِلما تتميز به من خواص كذلك تكون المادة األساس مواد بوليميرية. لقوى الصدم بد ع[أستروالبولي راتنج اإليبوكسي و الفينول لبوليمرية ميكانيكية وحرارية جيدة ، ومن األمثلة على المواد ا .]٢٠٠٠الفتاح، . (reinforcing material) مادة التقوية -٢ يجب توفر ميزتين أساسيتين في هكذا مواد وهي المقاومة العالية والمطيلية المنخفضة حتى تستطيع تقوية المواد (µm 1) والتي تكون بقطر أكبر من particulate) ( التقوية بالدقائقهناك عدة طرق للتقوية منها. األساس ويكون قطر الدقائق (dispersed)وبأشكال مختلفة منها اإلبرية والكروية والِقشرية ، كذلك تتم التقوية بالتشتت ميز به من قوة نظراً لما تت fibers)(أما أكثر أساليب التقوية شيوعاً فهي التقوية باأللياف. ( 0.1µm)أقل من مستمر أو مقَطع أو كبيرة مقارنة بالمواد الراتنجية ، وتكون األلياف بأنواع وأشكال مختلفة فمنها ما يكون بشكل .]٢٠٠٠بد الفتاح،ع[بشكل ظفائر محاكة .)fibers reinforcing(التقوية باأللياف الميكانيكية والفيزيائية للراتنجات حيث تزداد مقاومة إن الهدف الرئيسي من التقوية باأللياف هو لتحسين الخواص يطلق . الشد والصدمة والصالدة بشكل كبير مما يسمح بإستخدام هذه المواد المقواة في مجاالت صناعية عنيفة البوليمريـة لتفريقها عن المواد المحشوة وذلك (advanced composites) المواد المركبة بالمتقدمة هعلى هذ )filled polymers ( ]األلياف في هذا النوع من المواد المركبة هي المسؤول الرئيسي عـن إن .]١٩٩٩،علي ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٦ تحمل األحمال الخارجية ، ومن أكثر أنواع األلياف شيوعاً في مجال المواد المركبة المتقدمة هي ألياف الزجـاج .والكاربون وألياف كيفالر .) epoxy resin( راتنج اإليبوكسي حيث تتميز هذه الراتنجات بعدم إمكانية إعادة ة بالحرارةبينتمي راتنج اإليبوكسي إلى مجموعة الراتنجات المتصل تشكيلها بالحرارة بعد تحولها إلى مادة صلبة نتيجة لتكون سالسل بوليميرية طويلة متشابكة مع بعضها وهو مـا اإليبوكسي على مجموعتين أو أكثر مـن مجـاميع يحتوي راتنج ) .cross linking(يسمى بالربط التشابكي التي تتألف من ذرة ُأوكسجين مرتبطة مع ذرتي كاربون ترتبط مجموعـة اإليبوكـسي (epoxide)اإليبوكسايد (curing)كيميائياً مع الجزيئات اُألخرى لتشكيل شبكة ثالثية األبعـاد ذات ربـط تـشابكي بعمليـة المعالجـة ]efunda,2000[ . نج اإليبوكسي بالصالدة والمقاومة الكيميائية العاليتين نسبياً إضافة إلى ذلك يمتلـك هـذا يتميز رات الراتنج قابلية إلتصاق نوعي عالي بسبب التركيب الكيميائي لهذا الراتنج والمتمثـل فـي مجموعـة اإليثـرات الدة وقوة ، لذلك يستعمل في والهيدروكسيل والمجاميع القطبية التي تعطي متانة وإلتصاق عالية وتكسب المادة ص تتفاعل هذه الراتنجات مع المصلدات أثناء المعالجة ويكون التفاعل غير .التطبيقات التي تتطلب إداءاً وظيفياً عالياً وبالتالي %) ٢أقل من (مصحوب بإنبعاث الماء أو تحرر أي منتجات ثانوية مما يجعل التقلص الحجمي قليل جداً واص ميكانيكية عالية إضافة إلى ذلك تمتلك راتنجات اإليبوكسي المعالجة متانـة عاليـة يكتسب الراتنج قوة وخ . ]liyong,2002[ المتكاملة الربط التشابكي ووجود السالسل اإلليفانية نتيجة للبعد بين نقاط .)composite materials properties (خواص المواد المركبة خدامات العامة والهندسية للمواد المركبة إلى حد بعيد على خواصها الميكانيكية والفيزيائية مثل مقاومة تعتمد اإلست الشد والمرونة وقابلية المادة للإلستطالة ومقاومتها للحرارة والظروف البيئية مثل الرطوبة وأشعة الشمس وغيرها كثيراً على التركيب الجزيئي للراتنج وعلى وزنه إن جميع هذه الخواص تعتمد . من الخواص التطبيقية اُألخرى كما تعتمد هذه الخواص إلى حد كبير على مواد التقوية وعلى المواد المـضافة . الجزيئي وعلى القوى الجزيئية :ومن الخواص المناقشة في هذا البحث ما يأتي . ]morom,1990[مثل الحشوات والملدنات . (impact strength)مقاومة الصدمة -١ تُعبر مقاومة الصدمة عن قدرة المادة لمقاومة الكسر تحت تأثير حمل مفاجئ ، كما تعتبر مقياساً لمتانـة المـادة ويمكن تحـسين مقاومـة الـصدمة للراتنجـات . حيث المواد األكثر متانة هي التي تبدي أعلى مقاومة للصدمة ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٧ و إضافة الملدنات أو بترتيب وتراصف السالسل البوليمرية ولكـن بإضافة بعض المحسنات مثل مطاط بيوتادين أ .]morom,1990[أكثر الطرق فاعلية في تحسين مقاومة الصدمة هي التقوية باأللياف .( tensile strength)مقاومة الشد -٢ تتكـون . سحب المادة وكـسرها تعتبر مقاومة الشد مقياساً لقابلية المادة على مقاومة القوى الساكنة التي تحاول تبـدأ . المواد المركبة الليفية من ألياف قوية هشة مغمورة في المادة األساس التي تتصف بكونها أكثر مطيليـة المادة المركبة باإلستطالة بشكل خطي في البداية إستجابة للجهد المسلط ومع إستمرار التحميل يحصل إنحـراف نقطة الخضوع في حين تستمر األلياف باإلستطالة و المقاومـة حتـى تنهـار نتيجة لوصول المادة األساس إلى .]mittelman,1990[وعندما تتهشم المادة األساس تفشل المادة المركبة كلياً.مقاومتها .(hardness) الصالدة -٣ تلفة لتعيين صـالدة تُعرف الصالدة على إنها مقاومة المادة للخدش أو اإلختراق ، وهنالك ِعدة مقاييس عالمية مخ يحدث اإلختراق بمعدل بطيء في سطح النموذج . المواد اللدائنية وأكثرها شيوعاً صالدة برينل وصالدة روكويل أثناء تسليط القوة ألجل اإلختبار مما يؤدي إلى حدوث زحف موضعي ، وبعد زوال القوة المؤثرة تحصل إستعادة غيير أبعاد األثر المعتمد في حساب صالدة المادة ولمنـع حـدوث ذلـك بطيئة نسبياً في اإلختبار مما يؤدي إلى ت تبرز أهمية إختبـارات الـصالدة فـي .يتوجب اإللتزام بالفترة الزمنية المحددة لتسليط القوة على سطح النموذج إعطاء كشف سريع لما يطرأ من تغيرات على الخواص الميكانيكية للمادة نتيجة لعمليات التـصنيع والتغيـرات .]١٩٩٩،علي[الكيميائية والمعامالت الحرارية والتعتيق والتغيرات المصاحبة لعمليات التشكيل . ( flexural strength)مقاومة اإلنثناء -٤ وتعتبر هذه الخاصية مقياساً لمقاومة اإلنحناء ، ويمكن تعرفها على إنها أقصى حمل ساكن يمكن تـسليطه علـى عند تسليط حمل إنثناء على مـادة مركبـة . (mpa) قبل أن يخضع أو ينكسر وتقاس بوحدات نموذج اإلختبار طبقية فإن الجهود المناظرة تتناسب طردياً مع خواص المرونة للطبقات ومع ترتيبها داخل المادة المركبة الطبقية ه في السطح الخارجي كما في خواص الطبقات تؤدي إلى الشروع بالتشقق ضمن الطبقة أكثر من االختالفاتوإن . ]١٩٩٩،علي[يحصل مع المواد الموحدة الخواص ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٨ .)experimental work(الجزء العملي يتضمن الجزء العملي تحضير المواد األولية وكيفية تحضيرها إضافة إلى اإلختبـارات الميكانيكيـة التـي تـم .إجراءها على المادة المركبة .دمة في البحث المواد المستخ-أوالً :تم في هذا البحث إستخدام المواد التالية والتي تم تصنيع النماذج منها وهي .(ep-10)راتنج اإليبوكسي نوع كونبكسترا -١ يتصف هذا الراتنج بخواص مميزة عديدة منها لزوجته المنخفضة وخاصية إلتصاق عالية ويتميز بمعدل زحـف تم إستخدام . واطئ تحت تأثير األحمال الدائمية ويكون متماسكاً وال يحدث إنكماش بعد صبه في القالب وتصلبه حيث يحث التفاعل معهمـا فـي ]٣:١[ الذي يضاف إلى الراتنج بنسبة (metaphenylene diamic)المصلد . ة حرارة الغرفة جدر .(kevlar fibers) ألياف كيفالر -٢ والذي يحضر بالبلمرة التكثيفيـة لمركبـي (polyp-phenyleneterephthalamide)وهي عبارة عن بوليمر (terephthaloyl chloride)و (p-phenylenediamine) . ئة سلسلة بوليمرية خطية هذه األلياف تكون بهي تم في هذا البحث إستخدام ألياف كيفلر بشكل ظفائر محاكـة . غير متقطعة نتيجة الترابط الموجه لحلقات البنزين يوضح التركيب الكيميائي ألليـاف )١(الشكل رقم . (340g/cm3)ذات كثافة سطحية ) ٠°-٤٥°(ثنائية اإلتجاه .]١٩٩٩،علي[كيفالر . (test specimens preparation)لنماذج تحضير ا-ثانياُ :تم في هذا البحث تصنيع أربعة أنواع من النماذج خاصة باإلختبارات التي تم إجراءها وهي .(impact specimens) نماذج إختبار الصدمة -١ هـاز والمالئمة للفحـص فـي ج (astme23)تم تصنيع نماذج إختبار الصدمة حسب المواصفات القياسية ونـصف قطـر قاعـدة (mm 0.5)عمق الحز فـي النمـاذج . (charpy impact)الصدمة نوع شاربي . )٤٥°(حزوبزاوية (mm 0.25)الحز .(tensile specimens) نماذج إختبار مقاومة الشد -٢ . في تصنيع نماذج إختبار مقاومة الشد(iso – r – 527)تم إعتماد المواصفة القياسية . (hardness specimens) نماذج إختبار الصالدة -٣ ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٩ a f =σ ( )22 2 ddd d p hb −−⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × = π . (mm 10) وسمك (mm 25)تم تصنيع نماذج إختبار الصالدة على شكل أقراص دائرية بقطر .( flexural strength specimens) نماذج إختبار مقاومة اإلنثناء -٤ في تصنيع نماذج اإلختبار والتي كانت على شكل نماذج مستطيلة (astm d790)القياسية ُأعتمدت المواصفة .(10mm×135mm)بأبعاد تم تصنيع ثالث ِقطع من كل نموذج لجميع اإلختبارات والتي يختلف بنسبة راتنج الفينـول فورمالدهيـد ونـسبة ) .١( رقم الجدولالتقوية بألياف كيفالر وكما موضح في .(mechanical tests) اإلختبارات الميكانيكية – ثالثاً :تم إستخدام ثالثة إختبارات الميكانيكية للتعرف على خواص المادة المركبة ، وهذه اإلختبارات هي .(impact test) إختبار الصدمة -١ للتعرف على مدى مقاومة (charpy impact instrument)ُأستخدم جهاز فحص مقاومة الصدمة نوع شاربي .المادة المركبة لِحمل الصدم .( tensile test) إختبار مقاومة الشد -٢ ُأستخدم هذا اإلختبار لمعرفة خواص المادة المركبة تحت تأثير ِحمل شد محوري بإتجاه واحد ، حيث تم إستخدام . (kn 20) في قياس هذه الخاصـية وبمعـدل ِحمـل (universal instrument)جهاز اإلختبارات العام :ويمكن حساب مقاومة الشد من القانون اآلتي :حيث σ = مقاومة الشد(n/m2). f = الحِمل المسلط(n). a = مساحة المقطع العرضي للنموذج(m2). . ( hardness test)صالدة إختبار ال -٣ لحساب صالدة المادة المركبة ، حيث ُأستخدمت كرة فوالذيـة (brinell hardness)تم إستخدام طريقة برينل وبعد زوال القوة المؤثرة يتم قياس قُطر األثر (sec 15) لمدة (kg 10) مع تسليط ِحمل مقداره (mm 5)بقطر :ويمكن إستخراج قيم الصالدة من العالقة التالية .ح الناتج على السط :حيث hb = صالدة برينل(kg/mm2). p = سلطةالقوة الم(kg). ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٠ 22 3 bt ps sf =×=σ d = قُطر كرة اإلختبار(mm). d = قُطر األثر الناتج على السطح(mm). .( flexural strength test) إختبار مقاومة اإلنثناء -٤ يمكن قياس مقاومة اإلنثناء بطريقة اإلختبار ثالثي النقاط ويتم ذلك بإستخدام مكبس هيدروليكي متعدد األغـراض :لقياس أقصى حمل مسلط على منتصف نموذج اإلختبار ، ويمكن حساب مقاومة اإلنثناء من المعادلة التالية :حيث p = ى حمل يتحمله النموذج أقص(n). s = البعد بين نقطتي التحميل(mm). b = عرض النموذج(mm). t = سمك النموذج(mm). vi – النتائج والمناقشة )results and discussion( . م هكذا مواد ، حيث يجب أن تكون قـيم تمتلك الخواص الميكانيكية للمادة المركبة أهمية كبيرة في مجال إستخدا ومن خالل هذه اإلختبارات التي ُأجريـت علـى راتـنج . هذه الخواص عالية ومقبولة حتى تؤدي عملها بكفاءة المقوى بألياف كيفالر ثنائية اإلتجاه حـصلنا علـى النتـائج الموضـحة فـي (ep-10)اإليبوكسي كونبكسترا مقاومة الشد ومقاومة الصدمة والصالدة ومقاومة اإلنثناء نـسبة إلـى نـسبة المخططات البيانية والتي تُمثل قيم .التقوية باأللياف يوضح قيم مقاومة الصدمة مع نسبة التقوية باأللياف ، حيث تعتبر مقاومة )2(الشكل رقم . مقاومة الصدمة -١ ف تزداد قيمة مقاومة الصدمة الصدمة بشكل عام منخفضة للراتنجات نظراً لهشاشتها ولكن بعد تقويتها باألليا ويرجع السبب في ذلك إلى كون األلياف سوف تتحمل الجزء األكبر من طاقة الصدم المسلطة علـى المـادة و %) ٤٠(وهكذا تزداد مقاومة الصدمة مع زيادة نسبة التقوية باأللياف إلى . المركبة مما يحسن هذه المقاومة )٦٠. (% الـشكل ت من المواد الهشة حيث مقاومتها للشد منخفضة جداً وهذا ما نراه في تعتبر الراتنجا . مقاومة الشد -٢ ، ولكن عند إضافة األلياف إلى هذه المواد تتحسن مقاومتها للشد بصورة كبيرة حيـث إن الجـزء )3(رقم ميـز األعظم من الجهد المسلط تتحمله األلياف مما يرفع مقاومة الشد للمادة المركبة وذلـك ألن األليـاف تت ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢١ وتزداد مقاومة الشد بزيادة نسبة األلياف المضافة حيث تشِغل األلياف حيز أكبر داخل . بمطيليتها المنخفضة .الراتنج مما يسمح بتوزيع الِحمل المسلط عليها بشكل أفضل تـدني قيمـة )4(الشكل رقم تتميز المواد اللدائنية بشكل عام بإنخفاض صالدتها حيث نالحظ من . الصالدة -٣ قبل التقوية باأللياف ، إال إن قيمة الصالدة ترتفع بشكل حـاد (ep-10)صالدة راتنج اإليبوكسي كونبكسترا عند التسليح بألياف كيفالر نظراً لتوزيع الِحمل على األلياف مما يقلل معدل اإلختراق لسطح المادة المركبـة ة نسبة األلياف المضافة لنفس السبب المـذكور وتزداد صالدة المادة المركبة مع زياد . صالدتها ويرفع قيم .أعاله تمتلك المواد البوليمرية مقاومة إنثناء منخفضة وهذا راجع إلى هشاشة هذه المـواد وكمـا . مقاومة اإلنثناء -٤ المقوى (ep-10) الذي يمثل إختبار مقاومة اإلنثناء لراتنج اإليبوكسي كونبكسترا )5(الشكل رقم موضح في فالر ثنائية اإلتجاه حيث تكون قيمة مقاومة اإلنثناء منخفضة قبل التقوية باألليـاف ، ولكـن هـذه بألياف كي المقاومة تبدأ باإلرتفاع لهذا الراتنج بعد تقويته بألياف كيفالر ويعود السبب في ذلك إلى إرتفاع معامل مرونة ط على المادة المركبة مما يؤدي بدوره هذه األلياف مما يؤدي إلى تحملها إلى الجزء األكبر من الحمل المسل .وتزداد هذه المقاومة مع زيادة نسبة التقوية باأللياف . إلى زيادة مقاومة اإلنثناء لهذه المادة المقواة باأللياف .)conclusions ( االستنتاجات :من خالل النتائج التي تم الحصول عليها يمكن الخروج باإلستنتاجات التالية . كونه من المواد الهشة الفينول فورمالدهيدنخفاض قيم الخواص الميكانيكية لراتنجإ -١ ،لراتنج الفينول فورمالدهيد بعد تقويته بألياف كيفالر ثنائية اإلتجـاه تحسن قيم هذه الخواص الميكانيكية -٢ .وتزداد قيم الخواص الميكانيكية مع زيادة نسبة األلياف المضافة ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٢ . )references( المصادر .١٩٩٩،، رسالة ماجستير، جامعة بابل“تحسين خواص المواد اللدائنية المقساة ”علي هوبي حليم -١ المملكة دار المريخ للنشر ، الرياض “ أساسيات علم وتقنية البلمرات” عبد الفتاح محمود طاهر . د -٢ . ٢٠٠٠العربية السعودية ، 3efunda engineering fundamentals “ polymer material properties ”,2001. (www.efunda.com). 4liyong tong , adrian p.mouritz , michael k.bannister “ 3d fiber reinforced polymer composites ”, elsevier science ltd , first edition , 2002. 5g.morom , e.drukkler , a.weinbery , and j. banbaji “impact behavior of carbon/kevlar hybrid composite ” , composites , vol.17 , no.2 , 1990 , pp.150-153 . 5mittelman and i. roman “tensile properties of real unidirectional kevlar/epoxy composite ” , composites , vol.21 , no.1 , 1990 , pp.63-69 . تركيب نماذج اإلختبارات الميكانيكية:)١(الجدول رقم النموذج الثالث النموذج الثاني النموذج األول )القطعة( رقم النموذج ٤٠ ٦٠ ٨٠ %)نسبة وزنية (نسبة الراتنج ٦٠ ٤٠ ٢٠ %)نسبة وزنية (نسبة األلياف co co – nh nh ]١٩٩٩،علي[ التركيب الكيميائي أللياف كيفالر:)١(الشكل رقم ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٣ المقوى بألياف كيفالر (ep-10)لراتنج اإليبوكسي كونبكسترا مقاومة الصدمة ): 2(الشكل رقم reinforcing percentage (%) im pa ct s tr en gt h (k j/m 2 ) 0 20 40 60 80 0 50 100 150 200 250 المقوى بألياف كيفالر (ep-10)ونبكسترا لراتنج اإليبوكسي كمقاومة الشد ): 3(الشكل رقم reinforcing percentage (%) t en si le s tr en gt h ( m pa ) 0 20 40 60 80 0 100 200 300 400 500 ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢٤ reinforcing percentage (%) h ar dn es s ( n /m 2 ) المقوى بألياف كيفالر (ep-10)لراتنج اإليبوكسي كونبكسترا الصالدة :)4(الشكل رقم 0 20 40 60 80 0 20 40 60 80 100 120 reinforcing percentage (%) fl ex ur al s tr en gt h ( g pa ) المقوى بألياف كيفالر(ep-10) مقاومة اإلنثناء لراتنج اإليبوكسي كونبكسترا :)5(الشكل رقم 0 20 40 60 80 0.14 0.16 0.18 0.20 0.22 0.24 al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 73 study of microstructures and mechanical properties of friction stir welded pure aluminum hayder a. m. al-hameedi, haydar_alaa80@yahoo.com chemical engineering department, college of engineering, university of al-qadissiya received 12 november 2014 accepted 24 december 2014 abstract in this study commercially pure aluminum sheets were welded using friction stir welding (fsw) process. three rotational speeds of 800, 1100 and 1500 rpm were used. the axial force, passing speed, and tool geometry were constant. parameters were optimized depending on the results of the macrograph, micrographic, microhardness, and tensile strength. the results showed that the sound joint with the best possible microstructure and mechanical properties was obtained at a rotational speed of 1100 rpm. the microscopic and local mechanical properties proposed that mechanical mixing is the main material flow mechanism in the formation of the nugget zone (nz). keywords: friction stir welding; microstructure; heat affected zone ; weld nugget. الخالصة: في .( ملم3× 011× 051في هذه الدراسة تمت عملية اللحام التحريكي بين شريحتين من االلمنيوم التجاري النقي وبابعاد ) دورة بالدقيقة(. أثناء عملية اللحام تم تثبيت سرعة 0511و 0011و 011عملية اللحام هذه تم استخدام ثالث سرع دورانية وهي ) اللحام والقوة المسلطة وابعاد اداة اللحام. اختيار افضل العوامل المؤثرة على اللحام كانت على اساس فحص التركيب المجهري دورة بالدقيقة تعطي عينة بدون عيوب وافضل قيم للتركيب 0011الشد. بينت النتائج ان اللحام بسرعة وخواص الصالدة وقوة الجزيئي والخواص الميكانيكية. الفحص الجزيئي وتحليل الخواص الميكانيكية اثبتت بان الخلط الميكانيكي هي الميكانيكية االساية لجريان المادة في تكوين منطقة الكتلة الصلبة. nomenclature as: advancing side astm e3: american standard testing of materials bm: base metal d: tool shoulder diameter d: pin diameter al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 74 fsw: friction stir welding haz: heat affected zones nz: nugget zone rs: retreating side rt: rotational speed sssw: solid state stir welding tig: tungsten inert gas tmaz: thermomechanically affected zones v: welding traverse speed 1. introduction friction stir welding (fsw) is a solid state welding process in which the relative motion between the welding tool and the workpieces produces heat. this makes the material soft, and therefore it can be joined by plastic deformation diffusion. fsw has many advantages including low processing temperature, easy workpieces preparation, and it needs less shielding gases in the welds. fsw is a clean, environmental friendly and a non-harmful process as it is not accompanied by an arc formation, radiation and toxic gas emission [7].this method relies on the direct conversion of mechanical energy to thermal energy forming the weld joint without any external source of heat [9]. this heat causes the latter to “soften” without reaching the melting point and allows traversing of the tool along the weld line [8]. the plasticised material is transferred from the leading edge of the tool to the trailing edge of the tool pin and is “forged” by the intimate contact of the tool shoulder and the pin profile. in fsw process, a non-consumable rotating tool is forced down into the joint line under conditions where the frictional heating is sufficient to raise the temperature of the workpieces where it can plastically deform and locally plasticizes. as the welding tool is moved along the welding direction, sever plastic deformation and flow of this plasticised material occurs. the side where the direction of rotational tool is the same as that of welding is called the advancing side (as), whereas the other side designated as being the retreating side (rs). this difference in two sides can lead to asymmetry in material flow, heat transfer and the properties of the weld [9]. the schematic geometry of fsw process explained in fig. 1. there are two tool speeds to be considered in fsw; how fast the tool rotates and how quickly it traverses the interface. these two parameters have considerable importance and must be chosen with care to ensure a successful and efficient welding cycle. the relationship between the welding speeds and the heat input during welding is complex but, in general, it can be said that increasing the rotation speed or decreasing the traverse speed will result in a hotter weld. in order to produce a successful weld it is necessary that the material surrounding the tool is hot enough to enable the extensive plastic flow required and minimize the forces acting on the tool. if the material is too cold then voids or other flaws may be present in the stir zone and in extreme cases the tool may break. jayaraman et al. [4] studied the effect of process parameters on fsw of cast lm6 aluminum alloy joints. they concluded that the tool rotation speed is the most significant variable since it tends to influence the transitional velocity. for a given welding speed and axial force, adjusting the rotation speed of the tool leads to a al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 75 controlled stirring of the soft metal in the nugget zone and resulted in a smooth, non turbulent material flow. this prevents the formation of tunnel defect on the retreating side. however, the aim of this study is to examine the effect of rotational speeds of welding tool on the microstructures and mechanical properties of the welded joints. 2. experimental work the material used in this study was commercially available pure aluminum. the plates with a thickness of 3 mm were sliced into the required size (210 × 200 mm) using a cutting band saw machine (model: ue-712a). the chemical compositions of the base metal are presented in table 1. the microstructure of the received base metal is shown in fig. 2. the aluminum base metal has elongated grains in the rolling direction. test workpieces rigidly clamped on the backing plate in a butt-joint configuration parallel to the rolling direction of the plates. the surface of the plates was cleaned using acetone to remove dirt and grease. three pairs of workpieces were friction stir welded by a vertical milling machine, type kama (x6325; 3hp; trper r8; 30 kn). a non-consumable tool made of medium carbon steel was used to fabricate the joints which was heat-treated and quenched to 60hrc. the chemical compositions are listed in table 2. for the welding process, a tool with a smooth shoulder and cylindrical straight pin were used as shown in fig. 3. during the fsw process, 5 kn friction pressure was exerted to ensure that the plates were in good contact. the single pass welding procedure was followed to fabricate the joints. the welding parameters and the tool dimensions are shown in table 3. the welded samples were prepared for microstructure analysis and mechanical properties evaluation. the specifications of the cutting, grinding and polishing were done according to the american standard testing of materials (astm e3). the average vickers microhardness tester was performed on a (fv-700e), load of 1 kgf and dwelling time of 15 sec. finally, the fesem technique was also employed primarily to study the fracture surface of tensile specimens. for the tensile tests, the fsw plates were cut perpendicularly to the tool traverse direction and the test was carried out via 50 kn, instron-5569p7531 (universal testing machine). the specimens were loaded at the rate of 1kn/min. 3. results and discusion 3.1 results of macrostructure and microstructure the surface appearance of the fsw of similar aluminum using low rotational speed of 800 rpm was shown in fig. 4(a).the nz was not well performed and the semicircular metal traces are observed in the stir zone. the opening line between the two welded strips is evident. as the heat generated by the pin and the shoulder is proportional to the rotational speed, however it is clear that the heat input was not sufficient to produce defect free of welded joint [1]. at the root of the aluminum plates it can be seen that the two strips were also not successfully joined as shown in fig. 4(b).this may be attributed to poor heat generation and to the non firm clamping of the butt jointed aluminum pairs. at higher rotational speed of 1100 rpm the welded joint as shown in fig. 5 (a) and (b), explained that the surface morphology became smoother and free of defects, it reveals best possible weld surface as opposed to the welded joint conducted at 800 rpm. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 76 fig. 6(a) shows the surface morphology conducted at the highest utilized rotational speed (i.e. 1500 rpm), the surface shows onion rough rings like striated structure. the back side of the welded joint (fig. 6(b)) showed some cracks. the cracks evolved as a result of the excessive heat generated by fig. 6 shows the microstructures of the welded joint taken at magnification 100x using the optical microscope. the microstructure which is characterized by the central welded joints represents the nz. the material has been plastically deformed in this region which shows a combined action of a high strain rate at elevated temperatures by the fsw pin tool. the nz is surrounded by a thermomechanically affected zone (tmaz). it is suggested that this area is below the tool shoulder and the material in this part is plastically deformed without any dynamic recrystallization. the heat affected zone (haz) has modified the microstructure and the mechanical properties and fall between tmaz and unaffected base metal (bm). thus, there is no plastic deformation associated in this region and it has only a thermal cycle. bm is a remote material from the weld: an experimental perspective; it has a thermal cycle from the weld which is not affected by the heat in terms of microstructure or mechanical properties. . 3.2 mechanical properties 3.2.1 microhardness measurements fig. 8 represents the microhardness of the fsw joint at a rotational speed of 1100 rpm. the figure shows that the microhardness of the haz and the nz are lower than that of the bm. the difference in microhardness values between haz and nz is attributed to the grain refinement in nz due to the interaction of the pin with the material in this region, which leads to increase the microhardness according to eq. (1). this region experienced large plastic strain and the microstructure is highly refined as opposed to the bm. haz adjacent to the tmaz experiences a thermal cycle and mechanical shearing stress. it is more appropriate to overcome or minimize the haz softening to improve the mechanical properties of the welding joints. the microhardness in the stir zone was increased slightly with the decrease in the grain size according to the hall-petch relationship [3]; 21 .   dkhh hov (1) where hv is the microhardness, ho a n d kh are the appropriate constants associated with the hardness measurements. it was observed that the microhardness of the stir zone increased with the decreased in the friction heat flow because the grain size in the stir zone decreases when the friction heat flow is decreased. as seen in fig. 8, the traverse vickers microhardness is not uniform distribution across the stir zone. it can be observed that the microhardness of the bm is higher than haz, tmaz and nz, while the microhardness at the nz is a relatively higher than that of the haz and tmaz. this is attributed to the refining of the grain size in this region as mentioned previously in eq. (1). 3.2.2 tensile test tensile test was carried out for all specimens. fig. 9 shows the tensile stress and strain curves at rotational speed of 1100 rpm. the figure shows that the tensile strength of the welded line was higher than that of 800 and 1500 rpm, due to the best possible parameter of rotational speed. the tensile strength of the specimen welded at rotational speed of 1500 rpm showed lower strength due to excess of frictional heat generation. similar result was observed when there is insufficient heat generation. https://www.google.com.my/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&sqi=2&ved=0cdwqfjab&url=http%3a%2f%2fwww4.ncsu.edu%2f~murty%2fne509%2fnotes%2fch5d-strengthening.pdf&ei=j-fzukz_pishkgxa2ic4ag&usg=afqjcnhhs9bdyojhpggt77bdeuybrpcvsw&sig2=r-3yxu_7y96rkhxyo0uioq&bvm=bv.1357700187,d.bmk al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 77 conclusion in this study, workpieces of pure aluminum were welded successfully by fsw technique. microstructure and mechanical properties including tensile strength and microhardness behavior were studied and the following findings were achieved: 1. four different regions were distinguished in al-al fsw process; nz, tmaz, haz and the bm. 2. controlling the welding parameters particularly the rotational speeds and the pin shape leads to defect free of the welding joint. 3. it was found that there is an improvement of vickers microhardness in the nz due to further grain refinement and optimum amount of heat generation. for the same reasons the tensile strength results showed higher than that of bm when the joint fabricated at 1100 rpm. 4. rotational speed of 1100 rpm showed no sign of surface defect such as porosities, cracks and inclusions due to effective stirring action of the pin and best possible of heat generated. acknowledgement the author gratefully acknowledges the outstanding support provided by the staff of college of engineering. references [1] bahemmat p, rahbari a, haghpanahi m, besharati m. experimental study on the effect of rotational speed and tool pin profile on aa2024 aluminium friction stir welded butt joints. proceedings of ectc 2008, october 3-4, 2008, miami, florida, usa, p 11. 2008;1. [2] cho j-h, boyce de, dawson pr. modeling strain hardening and texture evolution in friction stir welding of stainless steel. materials science and engineering: a. 2005;398:146-63 [3] hirata t, oguri t, hagino h, tanaka t, chung sw, takigawa y, et al. influence of friction stir welding parameters on grain size and formability in 5083 aluminum alloy. materials science and engineering: a. 2007;456:344-9. [4] jayaraman m, sivasubramanian r, balasubramanian v. effect of process parameters on tensile strength of friction stir welded cast lm6 aluminium alloy joints. 2009;25. [6] liu g, murr l, niou c, mcclure j, vega f. microstructural aspects of the friction-stir welding of 6061-t6 aluminum. scripta materialia. 1997;37:355-61. [7] shukla rk, shah pk. comparative study of friction stir welding and tungsten inert gas welding process. indian journal of science and technology. 2010;3:667-71. [8] tang w, guo x, mcclure j, murr l, nunes a. heat input and temperature distribution in friction stir welding. journal of materials processing and manufacturing science. 1998;7:163-72. [9] thomas w, nicholas e, needham j, murch m, templesmith p, dawes c. international patent application no. pct/gb92, patent application. 1991. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 78 table 1 chemical compositions of the commercial pure al element al si fe mg cu mn wt % balance 0.114 0.405 0.032 0.08 0.011 table 2 chemical compositions of the welding tool element c mn p fe wt % 0.56 0.69 0.02 balance table 3: welding parameters and tool dimensions process parameters values rotational speed rt (rpm) 800 , 1100 , 1500 welding traverse speed v (mm/min) 40 axial force (kn) 5.0 pin length (mm) 2.5 tool shoulder diameter d (mm) 12 pin diameter, d (mm) 3 figure 1: schematic diagram of the fsw process. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 79 figure 2: microstructure of the aluminum base metal. figure 3:the welding tool configuration. figure 4: (a) front view and (b) back view of the al-al strips conducted at rotational speed of 800 rpm. 100µm (b) (a) gap nz al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 80 figure 5: (a) front view and (b) back view of the al-al strips conducted at rotational speed of 1100 rpm. figure 6: (a) front view and (b) back view of the al-al strips conducted at the highest rotational speed of 1500 rpm. figure 7: microstructures regions after fsw process. nz defect free (a) (b) 1µm 1µm crack onion like striated structure 100µm bm haz tmaz nz al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 81 figure 8: transverse vickers microhardness profile for the alal at a rotational speed of 1100 rpm. figure .9: tensile stress and strain of the welded joints and base metal. 0 20 40 60 80 100 120 140 160 0 0.5 1 1.5 2 2.5 3 3.5 t e n si le s tr e ss ( m p a ) tensile strain (%) 800 rpm 1500 rpm base metal 1100 rpm 0 10 20 30 40 50 60 70 -8 -6 -4 -2 0 2 4 6 8 v ic k e rs m ic ro h a rd n e ss ( h v ) distance from weld center (mm) n z t m a z h a z b m t m a z b m h a z al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 625 sulfates effect in fine aggregate on self compacting concrete properties by using rise husk ash received 12 july 2015 accepted 30 august 2015 abstract one of the important problems in fine aggregate is the contaminated with interior sulfates in manufacturing concrete in iraq. within standard specifications a difficult to obtain of well-graded fine aggregate with sulfates content is existed. the present research is devoted to enhancement of some properties of self-compacting concrete with fine aggregate contains internal sulfates by partial replacement of gypsum to fine aggregate by weight. this study is bifurcate of selfcompacting concrete they are: first category is incorporating powder of limestone (lsp) in selfcompacting concrete and the second one is incorporating 10% rise husk ash (rha) plus powder of limestone (lsp). the investigated scales of fine aggregate with sulfates contents were ( 0.37%, 0.5%, 1.0%, and 1.5%) which is corresponding replacement by weight of cement equal of (3.74%, 3.99%, 4.96% and 5.93%) for mixes contained limestone powder and of (3.76%, 4.01%,4.98% and 5.96%) for mixes contains rise husk ash plus powder of limestone. experimental program of this study is bifurcate; first one is using superplasticizers and fillers to produce self-compacting concrete then determine the workability. second one is to evaluate the mechanical properties such as splitting tensile strength and compressive strength. it was noticed that, the exemplary content of gypsum was by weight of cement for all mixes was 0.5%. while increase in compressive strength in a range between 5.9% and 10.1%, and in tensile strength in a range between 1.2% and 8.5% for mixes of self-compacting concrete with limestone powder plus rise husk ash instead of limestone powder. باستخدامالكبريتية في الركام الناعم على خواص الخرسانة ذاتية الرص حاألمالتأثير رماد قشور الرز dr. nabeel hasen ali al-salim lecturer in civil engineering, university of babylon dr_nabeelalsalim@yahoo.com haider mohammed majeed asst. prof. in civil engineering, university of babylon hdr_eng@yahoo.com dr. haider k. ammash asst. prof. in civil engineering, university of al-qadisyia e-mail:amashhk@gmail.com كاظم عماش رد. حيد أستاذ مساعد المدنيةقسم الهندسة كلية الهندسة جامعة القادسية حيدر مجيد البغدادي أستاذ مساعد قسم الهندسة المدنية كلية الهندسة جامعة بابل حسن علي السالم لد. نبي مدرس قسم الهندسة المدنية كلية الهندسة جامعة بابل al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 625 الخالصة من القياسية المواصفات ضمن. العراق في الخرسانة تصنيع في الداخلية الكبريتاتب تلوثه وه الناعم الركام في الهامة المشاكل من واحدة الخرسانة خواص بعض تعزيز إلى البحث هذا ويخصص. الكبريتات محتوى وجود مع الناعم الركام جيد تصنيف على الحصول الصعب الدراسة هذه. ايوزن الركام الناعم بالجبس استبداال من جزء استبدال طريق عن الداخلية الكبريتات على الحاوي الناعم الركام مع ذاتية الرص وثانية ذاتية الرص الخرسانة في( lsp) الجيري الحجر مسحوق دمج هي األولى الفئة: هم ذاتية الرص تنقسم الى صنفين الخرسانة من الناعم لركامل نتائج االستكشاف كانت(. lsp) الجيري الحجر مسحوق إلى باإلضافة ،(rha) من رماد قشور الرز٪ 01 دمج وه االخرىو و٪ 3335 ،٪333. ،٪353.) يساوي الى االسمنتمن وزن استبدال يقابلها والتي٪( 036و ،٪031 ،٪136 ،٪13.5) الكبريتات الحاوي على رماد قشور الرز الحاوية علىللخلطات ٪( 6335 و٪ 3334 ،٪3310 ،٪355.)و الجيري الحجر مسحوق للخلطات الحاوية على٪( .633 إلنتاج المادة المالئةو الملدنات استخدام هو قسم أول ؛ينقسم الى قسمين الدراسة هذه من الجانب العملي. الجيري الحجر مسحوق الى باالضافة . نضغاطاال وقوة لشد االنشطاريمقاومة ا مثل الميكانيكية الخواص لتقييم هو القسم االخرو. التشغيل قابلية تحديد ثم ذاتية الرص الخرسانة تقع ما بين االنضغاط قوة في الزيادة بينما٪. 136 كان الخلطات لجميع االسمنت من وزنا الجبس من القيمة المثلى تكان ،مالحظة ما يلي وقد رماد إلى باإلضافة الجيري الحجر مسحوق مع ذاتية الرص-الخرسانية للخلطات٪ 436 و٪ 032 تقع ما بين الشد قوةبينما ،٪0130 و٪ 633 .الجيري الحجر مسحوق من بدال قشور الرز ذاتية الرص، رماد قشور الرز، االمالح الكبريتية، الديمومة، الركام الناعم، مقاومة االنضغاط، مقاومة ةخرسانالمفاتيح الداللية: الشد 1. introduction during the last decade, self–compacting concrete (scc) is outstay in advances concrete technology. the scc is developed in japan since the last of 1980s, which is meanwhile spread all over the world with a continuously increasing of applications.( holschemacher and klug, 2002). self-compacting concrete (scc) was developed to respond to the need for concrete which can improve durability while eliminating the need for compaction and vibration work. scc can compact itself into complicated formwork and congested structural elements under its own weight without the need for mechanical vibration. it needs to be both highly deformable and resistant to segregation and bleeding (okamura and ouchi, 1999). because of highly flow-able nature of self-compacting concrete, care is required to ensure adequate stability, passing ability and excellent filling ability (sonebi and walraven , 2007) to achieve this ability, ensuring suitable rheological fresh concrete properties of like adequate plastic viscosity with a low yield stress. to attain high flow-ability for fresh concrete water to binder attribution could be to increase in a simple manner. increasing the water to binder ratio alone; however, might concrete to be less durability and lead to segregation. thus, mineral and chemical admixtures, e.g., pozzolans, limestone powder, super-plasticizer, and viscosity-modifying admixture (vma), need to be added to the mix for successfully develop scc and to prevent segregation and enhance the workability of scc (suksawang , nassif, and najm, 2006). sulfates cause concrete or mortar deterioration when it exists in excessive amount. this phenomenon is called sulfate attack. the sulfate reacting with ca(oh)2 with hydrate of calcium aluminates (h-c-a). the volume of gypsum and calcium sulphoaluminate products reactions is a considerably great in a comparison with the compounds they replace; therefore, expansion and disruption of the concrete will occur in the reaction with the sulfates. sulfate in fine aggregate is a major problem encountered in the middle and southern part of iraq. most of the sulfate salts in fine aggregate are composed of calcium, magnesium, potassium and sodium sulfates. calcium sulfate is the most predominant salt present in iraqi fine aggregate. it is usually finding in fine aggregate as al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 624 gypsum. about 95% of sulfates in fine aggregate are in the form of calcium sulfates because of the low solubility of this type of sulfate (al-samerai 1977 ). sulfates may come either from raw materials and or from gypsum added to cement at grinding stage. (al-qaisi,1989) stated that the activity of gypsum is dependent on its fineness. (al-rawi, ali, shallal and al-salihi, 1997) studied the effective sulfate content in concrete ingredients, they pointed out that the effect of so3 existing in cement on compressive strength of concrete is about two times more that in fine aggregate and effect of the latter is about two times more that in coarse aggregate. they attributed this to the fine particle size distribution of cement compared with fine aggregate and coarse aggregate. in a later study by (al-rawi, 2000), to develop the concept of effective sulfate content, he found that the effectiveness of sulfates increased with increased fineness of fine aggregate. he suggested a formula to account for the effectiveness of sulfates in fine aggregate depending on its fineness modulus. he showed also that the same formula is applicable. the sulfate content in fine aggregate contains sulfate higher than the acceptable limits in most of the fine aggregate in middle east countries (al-kadhimi and hamid, 1983). (al-ameeri and issa,2013) results show that the fresh properties such as decreased workability of self-compacting concrete is passively influenced from sulfate, also the hardened properties. furthermore, they found that the optimum so3 content to give little tendency to expanding and maximum strength is up to 5% (by weight of cement) which is acceptable limits more than iraqi specifications. in addition, they noticed a considerable reduction of self-compacting concrete mechanical properties, and increment in expansion of concrete after increase the optimum value of sulfates content in concrete.(alrawi,1997) investigated the effect of the gypsum content of cement on several engineering properties of concrete cured by accelerated and normal methods. he stated that increased gypsum content results in a significant decrease in the slump of concrete and that there is an optimum gypsum content, considerably higher for accelerated cured concrete than for normally cured concrete, at which maximum strength is obtained. the optimum gypsum content under accelerate curing conditions may be used without risk of reduction in the durability of concrete caused by excessive, delayed expansion. (alrawi, and latif, 1998), suggested a new test called "compatibility test" to investigate the possibility of using sands with relatively high (so3) contents with suitable cement without deleterious effect on concrete. the work was carried out on seven cements, three ordinary portland cement, three sulfate-resisting cements and white cement. the sand used had so3 contents between 0.18% and 1.5% and the mix was designed to give 30 mpa compressive strength at 28 days. the results show that the so3 content in sand gives the maximum concrete strength which differs from one cement to the other ranging from (0.18% to 1.5%) depending on the chemical composition and fineness of cement. (alwash, 2005) found the percentage in compressive strength of the mix with opc and sand of zone 2 which contains sulfate of 1.5% by weight of it, compared with the reduction in strength of the mix with opc and sand of zone 4 which contains sulfate of 1.5% by weight of it. at ages 7, 28 and 56 days the reduction was (30.86%-37.7%), (10.47%-17.9%) and (2.29%-8.16%) for air curing and (23.6%-28.4%), (7.7%-13.4%) and (5.8%-5.5%) for moist curing. the influence of sulfates on elastic modulus and indirect tensile strength was found to be somewhat likely to that influence on compressive strength. (hussain, 2008) investigated some mechanical properties of self-compacting concrete and effect of internal sulfates in fine aggregate on it with several filler types of such as powder of limestone, pigment and hydrated lime. the mechanical properties were flexural strength, modulus of elasticity, compressive strength, the ultrasonic pulse velocity, indirect tensile strength and schmidt al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 623 rebound hammer tests. he found the optimum gypsum content at which the strength is maximum . further increase in so3 content beyond the optimum causes a decrease in strength and nondestructive tests. (kawkab &elt, 2008) used 8% partial replacement by weight of cement rise husk ash, the results showed considerable increase in mechanical properties at all ages of curing simulated with the original concrete. (alwash, 2013) noticed in his experimental results that elastic modulus and strength of scc at age after 60 days improved by adding rice husk ash. the optimum strength was at 15% replacement. also, a reduction in water absorption and increase the ultrasonic pulse velocity was noticed using rice husk ash. 2. experimental program the research is devoted to enhancement of some properties of self-compacting concrete with fine aggregate contains internal sulfates by partial replacement of gypsum to fine aggregate by weight. the study is bifurcate of self-compacting concrete they are: first category is incorporating powder of limestone (lsp) in self-compacting concrete and second one is incorporating 10% rise husk ash (rha) plus powder of limestone (lsp). four scales of so3 contents in fine aggregate were investigated; these scales were 0.37%, 0.5%, 1.0% and 1.5% by weight of sand. in order to view the differences in behavior during the fresh state as well as the hardened state some of tests were performed. the slump flow, v-funnels, sieve segregation and l-box tests were performed on concrete in the fresh state. the tests for splitting tensile strength and compressive strength were carried out on concrete specimens at ages (28, 56 and 90 days). the details of each concrete mix were listed in table 1. 2.1 materials 2.1.1 cement the ordinary portland cement (named tasluja bazian) is used. the cement was tested and compared according to (iqs no.5 /1984). the chemical and physical tests were conducted in construction materials laboratory of babylon university. 2.1.2 fine aggregate (sand) al-akhaider natural fine aggregate with fineness modulus (2.64) was used throughout this work. results indicate that the fine aggregate grading, physical properties and the sulfate contents are within the requirements of the iraqi specification limits (iqs no.45 /1984). 2.1.3 coarse aggregate (gravel) rounded coarse aggregate of passing sieve size 10 mm from alnibaee quarry is used. the coarse aggregate was washed and then stored in air to dry. the grading of this aggregate which conforms to iraqi specifications limits (iqs no.45/1984). the specific gravity and sulfate content of coarse aggregate are within the requirements of the iraqi specifications limits (iqs no.45 /1984). 2.1.4 water for both mixing and curing all specimens ordinary tap water is used. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.1 2.1.5 superplasticizer a chemical admixture based on modified polycarboxylic ether, which was known commercially (glenium 51) was used in producing scc as a superplasticizer admixture. it was complied with (astm c494-05 type f). 2.1.6 limestone powder (lsp) limestone powder is a white ground material from limestone that found in different regions in iraq, and usually used in the construction processes. limestone powder that has been brought from local market is used to increase the amount of powder (cement + filler), the fraction less than 0.125mm will be of most benefit. this filler conforms the (bs 7979) . the chemical analysis of lsp was listed in table 2. 2.1.7 gypsum the gypsum was added to the fine aggregate to obtain the required so3 content. the added gypsum is natural gypsum rock (brought from kufa cement factory). it was crushed and grounded to obtain nearly the same gradation set of fine aggregate used in the mix. this gypsum was using as a partial replacement by weight of fine aggregate with limited percentages. the quantity of natural gypsum was calculated and added to the fine aggregate according to the following equation(al-kadhimi and hamid, 1983). w=(r – m) s / n (2-1) where: w= the weight of natural gypsum needed to be added to fine aggregate. r= the percentage of so3 % desired in fine aggregate. s = the weight of fine aggregate in mix. m = the actual so3 in fine aggregate (0.37 %). n= the percentage of so3 % in the used natural gypsum. 2.1.8 rise husk ash (rha) prepared of rice husk ash was by burning the husk in a controlled temperature furnace in order to get a pozzolanic material rich in amorphous silica and minimum amount of unburned carbon. generally, the optimum burning condition was 500 o c for 2 hours (al-khalaf and yousif, 1984). a grinding mill effected the grinding of ash for a period of 15 hours for each 0.5 kg of the ash. the fineness was determining by blaine air permeability method in accordance with (astm c204-84). the fineness modulus and specific gravity were 1.45 and 1.85, respectively. the chemical properties of rise husk ash (rha) were listed in table 3. 2.2 mixing procedure in order to obtain the desired level of so3 in the sample, first adding suitable amount of gypsum to the fine aggregate then fine aggregate and gypsum were mixed until a homogeneous mix is obtained. rise husk ash (rha) powder was mixed with the quantity of cement with the aid of al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.0 trowels, until the rha particles were thoroughly dispersed between cement particles. mixing procedure is important to obtain the required workability and homogeneity of the concrete mix. concrete was mixed in drum laboratory mixer, with a capacity of 0.05m 3 . before starting to mix, it is necessary to keep the mixer clean, moist and free from previous mixes. the procedure used for mixing the batches was as follows (emborg ,2000): 1. adding the fine aggregate to the mixer with 1/3water, and mixing for 1minute. 2. adding the powder (cement+filler) with another 1/3 mixing water, and mixing for 1 minute. 3. after that, the coarse aggregate was added with the last 1/3mixing water and one third of superplasticizer, and mixing for 1.5 minute then the mixture is left for 1.5 minute for rest. 4. then, the remaining of superplasticize (two third) is added and mixed for 1.5 minute. the scc mix proportions were summarized in table 4. 2.3 test methods for fresh (scc) the fresh properties of plain scc were tested by the procedures of (european guidelines for selfcompacting concrete) (efnarc, 2005). scc was defined by its behavior when it is in the fresh state, and it is determined whether concrete meets certain requirements, while flowability is an essential property in qualifying concrete as scc or not. the slump flow, l-box, v-funnel, sieve segregation test and v-funnel at t5 minutes were all used for all mixes of this study. 2.3.1 slump flow and t50cm tests the most widely used method for evaluating concrete consistency and filling ability in the laboratory and at construction sites is the slump flow test and can indicate segregation resistance of scc to an experienced user. slump flow with abrams cone was used to investigate flowing ability of fresh concrete. the slump spread values and t500 for the produced mixes listed in table 5. 2.3.2 l-box test the passing ability of self-compacting concrete is measures by the l-box test. originally developed in japan for underwater concrete. table 5 shows the value of lbox (h1/h2) which represents the blocking ratio and the value of t400 represents the time of concrete to reach 400 mm flow. 2.3.3 v-funnel test and v-funnel at t5 minutes tests to evaluate the material segregation resistance and to measure the filling ability (flowability) of scc the v-funnel can be used. table (5) shows test results of v-funnel. no blocking or segregation behavior observed in all mixes, and these results are within the limits pointed out in the literatures. 2.3.4 sieve segregation resistance test to assess the resistance of (scc) to segregation sieve segregation test is used. table (5) shows the value of segregation resistance results test of (scc) mixes. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.2 2.4 testing of hardening (scc) 2.4.1 compressive strength according to iraqi specification (iqs no.348-1992), compressive strength test was carried out on 150 mm cubes by using a hydraulic compression machine with a capacity of 2000 kn. for each test average of three cubes was adopted. 2.4.2 splitting tensile strength according to the procedure outlined in iraqi specification (iqs no.283-1995), indirect tensile strength was carried out. cylindrical concrete specimens (100x200 mm) were used. in each test average of three specimens is taken. 3. results and discussions 3.1 compressive strength the compressive strength test results of the concrete specimens were tested at ages (28, 56 and 90 days), three cubes are tested at each age to compressive strength of self-compacting concrete with various percentages of gypsum content in fine aggregate are shown in table ( 6) and figs. (1) and ( 2) .it can be seen that for all mixes, there is an optimum so3 content at which the compressive strength is maximum, beyond which content the compressive strength has decreased. the present data indicates that the optimum so3 content for these mixes is about (0.5) % (by weight of sand) and it is equal to 3.99 % (by weight of cement) for mixes that contain limestone powder filler and it is equal to 4.01% (by weight of cement) for mixes which contain limestone powder filler and rise husk ash (rha). from the results of compressive strength shown in table 6, and fig. 1 and 2 it can be noticed that: 1. when so3 content in fine aggregate increases from (0.37 to 0.5%), this leads to an enhancement in compressive strength of concrete cubes in the range (5.9, 7, and 8.7%) for dl1 at ages (28, 56 and 90) days respectively. 2. when so3 content in fine aggregate increases from (0.37 to 1%), this leads to a diminution in compressive strength of concrete cubes in the range (5.4, 6.8 and 7.7) % for dl2 at ages (28, 56 and 90) days respectively. 3. when so3 content in fine aggregate increases from (0.37 to 1.5%), this produce to a diminution in compressive strength of concrete cubes in the range (8.2, 8.8 and 9.9 %) for dl3 at ages (28, 56 and 90) days respectively. this was expected since several researchers as mention before, had referred to the presence of optimum gypsum content. the enhancement in compressive strength of the concrete can attribute to the ettringite formation, which was produced by a chemical reaction between so3, c3a and water. it fills some of the voids inside the cement past and increases the strength. but more ettringite formation motives internal stresses and decreases the compressive strength (neville, 1995) and (alameeri and issa,2013). also, results showed that the use of 10% rise husk ash (rha) in self-compacting concrete was the best compared with other mixes that contain limestone powder (lsp) by improving compressive strength for all sulfates contents and for all ages as shown in fig's below . al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.. figs. (3) and (4) show the effect of rise husk ash (rha) on compressive strength at ages 28 and 90 days with increment percentage as (24.6, 26.7, 29.9 and 27.1)% at 28 days and (28.5, 30.5, 30.9 and 30.9) at 90 days for levels of sulfates contents in fine aggregate ( 0.37, 0.5, 1.0, and 1.5)%. the results indicated that the (scc) with (rha+lsp) yielded the lowest compressive strength loss when compared (scc) with (lsp), this can be attributed to the fact of the incorporation of (rha) in scc mix leads to minimizes the compressive strength loss compared to mixes without (rha). this behavior because of pozzolanic effect of (rha) which reacts with the calcium liberated (during the hydration of cement) and contributes to densification of the concrete matrix resulting in a considerable increase in strength and reduction in permeability. also, the grain size and pore-size refinement process associated with pozzolanic reaction can effectively reduce the microcracking and strengthen the transition zone (neville, 1995). 3.2 splitting tensile strength splitting tensile strength (indirect tensile strength) of self-compacting concrete results of the (28, 56 and 90 days) with various percentages of so3 content in sand are presented in table (7) and figs.(5) and fig.(6) for different mixes. it is clear that the effect of sulfates on the indirect tensile strength is somewhat similar to that on compressive strength. for all mixes, there is an optimum so3% content at which the splitting tensile strength is maximum, beyond this content indirect tensile strength has decreased. from the results of splitting tensile strength shown in figs. 5 and 6 it can be it can be noticed that: 1. when so3 content in fine aggregate increases from (0.37% to 0.5%), this leads to enhance in indirect tensile strength of the concrete cylinders in value of (1.2., 4.5 and 6.4 %) for dl1 at ages (28, 56 and 90) days respectively. 2. when so3 content bin fine aggregate increases from (0.37 to 1%), this leads to a decrease in indirect tensile strength of the concrete cylinders in the range (3.3, 3 and 2.7%) for dl2 at ages (28, 56 and 90) days respectively. 3. when so3 content in fine aggregate increases from (0.37% to 1.5%), this leads to a decrease in indirect tensile strength of the concrete cylinders in value of (5.6, 5 and 4.8%) for dl3 at ages (28, 56 and 90) days respectively. these results agree with that obtained by (alwash, 2005) and (hussain, 2008). in addition also, results showed that the use of 10% rise husk ash (rha) in self-compacting concrete was the best compared with other mixes that contain limestone powder (lsp) by improving splitting tensile strength loss for all sulfates contents and for all ages as shown below : 1. when so3 in fine aggregate increases from (0.37% to 0.5%) this leads to an increase indirect tensile strength of the concrete cylinders in value of (4.7, 6.2, and 8.5%) for dlr1 at ages (28, 56 and 90) days respectively. 2. when so3 in fine aggregate increases from (0.37 to 1%), this leads to a decrease indirect tensile strength of the concrete cylinders in value of (2.4, 2.6 and 2.1%) for dlr2 at ages (28, 56 and 90) days respectively. 3. when so3 in fine aggregate increases from (0.37 to 1.5%) this leads to a increase indirect tensile strength of the concrete cylinders in value of (4.5, 4.0 and 3.8%) for dlr3 at ages (28, 56 and 90) days respectively. figs. 7 and 8 show the effect of rise husk ash (rha) on indirect tensile strength at ages 28 and 90 days with increment percentage as (25.3, 29.7, 26.5, and 26.8%) at 28 days and (25.0, 27.5, 25.7 and 26.3) at 90 days for levels of sulfates contents in fine aggregate ( 0.37, 0.5, 1.0, and 1.5%). al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.3 4. conclusions the following conclusions can be noticed from the experimental work, 1. with a constant superplasticizer dosage and water content, (scc) mixes with (lsp) had a better a passing ability filling ability, and segregation resistance than (scc) mixes with (rha+lsp) in the fresh state. 2. there is an optimum gypsum content in which both indirect tensile strength and compressive strength are maximum, beyond this content the splitting tensile strength and compressive strength decrease. the optimum gypsum content for these mixes is about (0.5% by weight of fine aggregate) and it is equal to (3.99%) by weight of cement for mixes containing (lsp), while it is equal to (4.01% by weight of cement) for mixes containing (rha+lsp). 3. the (scc) which contain 10% (rha) as a partial permutation by weight of cement in mixes contain (rha+lsp) was found to be effective in reducing compressive strength and splitting tensile strength due to interior sulfates contents in fine aggregate beyond optimum gypsum contact as compared with mixes contain (lsp). references [1] holschemacher, k., and klug, y.,(2002) “a database for the evaluation of hardened of scc”, lacer no. 7, 2002, pp.123-134. [2] okamura, h. and ouchi, m., (1999), “self-compacting concrete development, present and future”, proceedings of the first international rilem symposium on self-compacting concrete, pp.(3-14). [3] sonebi , m. , grünewald , s., and walraven , j.(2007) , “filling ability and passing ability of self-consolidating concrete” , aci materials journal , v. 104, no. 2, march-april , pp.162170. [4] suksawang ,n., nassif, h., najm, s., (2006) “evaluation of mechanical properties for self consolidating, normal, and high-performance concrete(hpc)”, new jersey department of transportation (njdot) and the center for advanced infrastructure and transportation (cait) at rutgers, pp.3. [5] al-samerai m. ,( 1977 )“limitation of sulfate in sand”, national center for construction laboratory, civilization journal, no. 1 , 1977, pp.38-52. [6] al-qaisi, w.a., (1989) “the activity of sulfate contaminating fine aggregate in concrete", m.sc. thesis, university of baghdad, college of engineering. [7] al-rawi, r.s., ali, n.h., shallal, a.r. and al-salihi, r.a., (1997) “effective sulfate content in concrete ingredients", 4th scientific and engineering conference, baghdad,pp.1820. [8] al-rawi, r.s., (2000) “some problems in concrete manufacture in the arab homeland and suggested remedial measures", arab conference of construction materials in egypt , pp.669681. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.6 [9] al-kadhimi, t. k. and hamid, f. a., ( 1983) “ effect of gypsum present in sand on the properties of concrete", brc-journal, vol.2, no.2, , pp.17 41. [10] al ameeri ,a and issa ,r. h., “effect of sulfate on the properties of self compacting concrete reinforced by steel fiber”, international journal of civil engineering & technology (ijciet), volume 4, issue 2, 2013, pp. 270 287, issn print: 0976 – 6308, issn online: 0976 – 6316. [11] alrawi r.s.,(1997), “gypsum content of cements used in concrete cured by accelerated methods", journal of testing and evaluation v.5, no.3, may, pp. 231-236. [12] alrawi, r.s and latif a., (1998) “ compatibility of sulphate contents in concrete ingredients", fourth scientific conference , college of engineering of baghdad university. [13] alwash, j.j., (2005) “effect of sulfates in fine aggregate on drying shrinkage cracking in end restrained concrete members" m.sc. thesis, university of babylon, college of engineering [14] hussain, t. h., (2008) “ effect of sulfates in fine aggregate on some mechanical properties of self compacting concrete". m.sc. thesis, university of babylon, college of engineering [15] kawkab h. al-rawi , mazin t. al-kuttan , rawa'a a. al-niemey “some mechanical properties of pumice lightweight aggregate concrete incorporating rise husk ash” university of technology,2008 [16] alwash, j.j.,(2013)“self compacting concrete incorporating rice husk ash and metakaolin” babylon university, college of engineering, al-qadisiyia journal for engineering sciences ,vol. 6,no 2 . [17] iraqi specification, no.5/1984, “portland cement” central organization for standardization &quality control cosqc, baghdad, 2001 [18] iraqi specification, no.45/1984, “aggregates from natural sources for concrete and construction” central organization for standardization &quality control cosqc, baghdad, 2001. [19] american society for testing and materials, astm c 494-05, “standard specification for chemical admixtures for concrete “annual book of astm standards, vol. 04-02, 2005. [20] british standards institution ,bs 7979-01, specification for limestone fines for use with portland cement. [21] al-khalaf, m.n., and yousif, h.a., "use of rice husk ash in concrete", the international journal of cement composites and lightweight concrete, vol.6, no.4, nov, pp. 241-248,.1984. [22] astm c204-84, "standard test method for fineness of portland cement by air permeability apparatus", annual book of astm standards, vol. 04-02, pp.157-162,1989 [23] emborg m., ,(2000) “ mixing and transport ", brite euram, task 8.1. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.5 [24] efnarc, (2005), ”the european guidelines for self-compacting concrete specification, production and use”. the european federation of specialist construction chemicals and concrete systems. [25] iraqi specification, no.348/1992, ”determination of compressive strength of concrete cubes”, central organization for standardization &quality control cosqc, baghdad. [26] iraqi specification, no.283/1995, ”splitting tensile strength of concrete” , central organization for standardization &quality control cosqc, baghdad [27] neville, a.m., (1995), “properties of concrete'', five, and final edition, wiley, new york and longman, london, pp.844. oxides of rha percentage oxides of rha percentage sio2 93 al2o3 0.1 cao 1.31 p2o3 0.56 mgo 1.7 cl 0.36 mixes designation types of filler curing time (days) so3 content in sand (by weight of sand) % total so3 content (by weight of cement) % dl* 0 dl 1 dl 2 dl 3 limestone powder (lsp) 28, 56, 90 0.37 0.5 1.0 1.5 3.74 3.99 4.96 5.93 dlr *0 dlr 1 dlr 2 dlr 3 limestone powder plus rise husk ash (lsp+ rha) 28, 56, 90 0.37 0.5 1.0 1.5 3.76 4.01 4.98 5.96 oxide content % oxide content % sio2 1.34 mgo 0.13 fe2o3 0.12 so3 1.90 al2o3 0.69 cao 55.13 table (1): concrete mix designations table(2): limestone powder chemical analysis table(3) rice husk ash chemical and physical properties[21]. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.5 table( 6): effect of sulfate content in fine aggregate on compressive strength of scc so3 0.1 fe2o3 0.31 k2o 3.77 mno 0.2 na2o 1.5 l.o.i 2.51 materials materials content limitation (kg/m3) cement (kg/m 3 ) 400 350-450 fine aggregate (kg/m 3 ) 775 710-900 coarse aggregate (kg/m 3 ) 820 750-920 filler (kg/m 3 ) 100 50-150 (water / powder) ratio 0.42 0.33-0.62 sp (liter/100kg cement) 3 test unit mix notation typical range of values dl dlr slump-flow mm 740 680 600-800 t 50cm sec 3 3.5 2-5 v-funnel sec 6 7 6-12 v-funnel at t5 min. sec. 7 9 +3 sec, max. l-box (h2/h1) 1 0.9 0.8-1.0 sr % 3 2 ≤ 15% mix notation so3 content % by weight of fine aggregate total so3 content % by weight of cement compressive strength (mpa) for ages 28 (days) 56 (days) 90 (days) dl0 0.37 3.74 35.3 39.7 42.4 dl1 0.5 3.99 37.4 42.5 46.1 dl2 1.0 4.96 33.4 37 39.1 dl3 1.5 5.93 32.4 36.2 38.2 dlr0 0.37 3.76 44.0 50.1 54.5 dlr1 0.5 4.01 47.4 54.3 60.0 dlr2 1.0 4.98 43.4 47.5 51.2 dlr3 1.5 5.96 41.2 46.4 50.0 table (4): mix proportions table (5) results of fresh properties of ssc of all mixes al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.4 table(7) effect of sulfate content in fine aggregate on splitting tensile strength of scc mix notation so3 content % by weight of fine aggregate total so3 content % by weight of cement splitting tensile strength (mpa) for ages 28 (days) 56 (days) 90 (days) dl0 0.37 3.74 3.36 3.58 3.76 dl1 0.5 3.99 3.40 3.74 4.0 dl2 1.0 4.96 3.25 3.47 3.66 dl3 1.5 5.93 3.17 3.4 3.58 dlr0 0.37 3.76 4.21 4.52 4.70 dlr1 0.5 4.01 4.41 4.80 5.1 dlr2 1.0 4.98 4.11 4.4 4.6 dlr3 1.5 5.96 4.02 4.34 4.52 0.0 0.5 1.0 1.5 2.0 so3% in fine aggregate 30 35 40 45 50 c o m p re s s iv e s tr e n g th ( m p a ) ssc mixes with lsp 28 days 56 days 90 days 0.0 0.5 1.0 1.5 2.0 so3 % in fine aggregate 35 40 45 50 55 60 65 70 c o m p re s s iv e s tr e n g th ( m p a ) ssc mixes with lsp and hrm 28 days 56 days 90 days fig. 1: relationship between compressive strength and so3 content in fine aggregate at different age with limestone powder filler. fig. 2: relationship between compressive strength and so3 content in fine aggregate at different age with limestone powder filler and rise husk ash (rha). al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 6.3 0.0 0.5 1.0 1.5 2.0 so3% in fine aggregate 4.0 4.4 4.8 5.2 s p li tt in g t e n s il s tr e n g th ( m p a ) ssc mixes with lsp and hrm 28 days 56 days 90 days 0.0 0.5 1.0 1.5 2.0 so3 in fine aggregate % 2.8 3.2 3.6 4.0 4.4 s p li tt in g t e n s il e s tr e n g th ( m p a ) ssc mixes with lsp 28 days 56 days 90 days fig. 6: relationship between splitting tensile strength and so3 content in fine aggregate at different age with limestone powder filler and rise husk ash (rha). fig. 5: relationship between splitting tensile strength and so3 content in fine aggregate at different age with limestone powder filler. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 95 modification of baghdad potable water by using recycle waste glass asst. prof. dr. besma m. fahad asst. lecturer hyman jafar meerza material eng. dep. /college of engineering material eng. dep. /college of engineering al mustansiriya univ. /baghdad. iraq. al mustansiriya univ. /baghdad. iraq. received 16 september 2015 accepted 7 january 2016 abstract modification or purification of potable water with the use of recycle waste glass reduces the drain on the natural resources of the raw materials, which is widely used in our daily life. however, the disposal of waste glass is not an easy matter, which is because glass is neither incinerated nor decomposed material. in this study, ten samples of potable water were collected from ten regions in baghdad capital city in order to investigate their physical and chemical properties. chemical and physical properties of water were identified. several parameters of water quality were analyzed including: turbidity, electrical conductivity, and acidity function (ph) and total suspended solids according to iraqi standards. the results of all water samples showed that the physical and chemical analysis tests were acceptable for drinking except the station of madinat alsadar. using the waste glass to eliminate this problem, as low cost and inert material, was successful in potable water treatment. as a conclusion, the tss was decreased after filtration process by waste glass especially for althaalba and alameria potable water which were disappeared (being zero). keyword: modification, purification, potable water, total suspended solids, waste glass. ملخص: مياه الشرب مع استخدام نفايات الزجاج المعاد تدويرها يقلل من استنزاف الموارد الطبيعية من المواد الخام، و الذي تعديل او تنقية يستخدم على نطاق واسع في حياتنا اليومية، ويرجع سبب ذلك كون الزجاج من المواد التي ال تحرق وال تتحلل. لعشرة مناطق في العاصمة بغداد من اجل التحقق من الخواص الفيزيائية في هذه الدراسة تم جمع عشر عينات من مياه الحنفية ك: والكيميائية للماء. وقد تم تحديد الخواص الفيزيائية و الكيميائية، وتم تحديد العديد من المعامالت المحددة لنوعية المياه بما في ذل الصلبة العالقة وفقا للمعايير العراقية. ( و مجموع الموادphالعكورة، التوصيل الكهربائي، معامل الحموضة ) واظهرت نتائج جميع عينات المياه من خالل االختبارات الفيزيائية و الكيميائية بانها مقبولة للشرب ماعدا محطة مدينة الصدر، كانت ناجحة في معالجة مياه واستخدمت نفايات الزجاج للقضاء على هذه المشكلة، كونها منخفضة التكلفة و تعتبر من المواد الخاملة، إذ ( قد انخفضت بعد عملية الترشيح باستخدام نفايات الزجاج و خاصة بالنسبة لمياه الشرب لمنطقتي tssالشرب. و كاستنتاج، فان ) الثعالبة و العامرية حيث اختفت و اصبحت )صفر(. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06 nomenclature: ec: electrical conductivity. ph: potential hydrogen. tss: total suspended solids. introduction: water remains the most important requirements of daily life and it must be accorded to its importance for the processing of citizens conform to the standard specifications. filtration is a process by which suspended solid particles are separated from a liquid by passing the liquid through a porous. in this filtration process, waste glass was aimed to use. with the rapid economy growth and continuously increased consumption, a large amount of waste materials is generated. among them, waste glass material is an important part. glass is a non-metallic and inorganic material made by sintering selected raw materials, so it can neither be incinerated nor decomposed. glass recycling can save energy and decrease environmental waste. focus on glass recycling technology will also widen the application domain of waste glass and promote further development of glass techniques. the increasing awareness of glass recycling speeds up focus on the use of waste glass with different forms in various fields. large amounts of domestic, industrial and mining waste are generated annually in each country. the use of recycled materials instead of virgin materials will reduce the demanding of virgin materials. (simon o. rutledge and graham a. gagnon 2002) evaluated the performance of a pressure filter utilizing crushed glass as the filter media in a dual media anthracite–glass filter compared to a dual media anthracite–sand filter. after 6 months, they found that the crushed glass used in this project had a higher angularity and slightly higher uniformity coefficient then the sand tested.(yuliazakharova and andrew wheatley 2008), for metal removal (copper, iron and zinc) from urban runoff, recycled crushed glass was used as filtration medium. the results indicate that glass can be effectively used for the removal of a metal such as iron in its total form, whereas this medium is likely to be less effective for metals like copper and zinc which are predominantly found in the dissolved form. (habayeb abdul al-hussein majid2008) worked on modern paint company waste water thrown into the tigris river to investigate how it is agree with the iraqi specifications of rivers protection system by measuring: ph , bod , tds , tss , so4 -2 , po4 -3 , no3 -1 , cl-1. it was showed by results that the specifications of water coming from the treatment unit have been within the limits except the biological need for oxygen for some samples because of damage in the aeration pumps. (healy, m.g., et. al. 2010) examined the performance of intermittently loaded filter columns comprising different media – sand, crushed glass and soil. they concluded that 100% of total suspended solids (tss) were removed and nitrification was complete, and bacterial numbers were reduced by over 80%, with best removals achieved in the soil filters (93%). (elifsoyer et. al. 2010), for rapid filtration, crushed recycled glass was used as a medium. two physically identical filter columns were operated in parallel in all the experiments. one filter contained a silica sand medium, whereas the other filter contained crushed recycled glass. the observations were (1) provided that a coagulant was used, the filter containing crushed glass produced effluent turbidities and particle counts similar to those obtained with the sand filter. (2) the crushed glass medium generated both a smaller clean-bed head loss and smaller clogging head losses than those of the sand filter. it is concluded that crushed glass shows significant promise as an alternative to silica sand in rapid filtration (l. w. gill, al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06 et. al. 2011) treated the efficiency of two stratified filters in parallel (one with sand as a media, the other with recycled glass) receiving secondary treated effluent from a single house which also operated as a bed and breakfast has been compared over a two year period. it is found that a layer of 100 mm of limestone sand was also included in both filters to target phosphorus removal. the evidence was that the limestone layer started to approach saturation particularly in the glass filter with a reduction in removal efficiency apparent over time. (rafahalsuhaili et. al. 2012)studied the ability of using crushed glass solid wastes in water filtration by using a pilot plant, constructed in al-wathba water treatment plant in baghdad. different depths and different grain sizes of crushed glass were used as mono and dual media with sand and porcelaniate in the filtration process. the mathematical model by tufenkji and elimelech was used to evaluate the initial collection efficiency η of these filters. the results designated that the collection efficiency varied inversely with the filtration rate. all the dual filters showed that theoretical values ηth was less than practical values ηprac. whereas the dual filter 35cm porcelanite and 35cm glass showed the highest collection efficiency. the main objective of this study is to investigate the benefit of using a recycled waste glass as filter in treating portable water, to examine how it could remove total suspended solids or reduce them from portable water, and to find out the effect of using waste glass as a filter on the physical and chemical properties of water. experimental methods 1. materials used and equipments: a. ten samples of water b. waste glass c. filter paper and funnels d. beakers e. ph meter f. electrical conductivity meter g. turbidity meter h. oven i. digital balance 2. tests 2.1. ph test: ph is a measure of the acidity or alkalinity of the water. the ph test is one of the most common analyses done in volunteer estuary monitoring programs.it is measured on a scale from 0 – 14.in this study, the electronic ph meter is used. the ph of the water is different depending on a number of conditions (apha, et. al. 2005): 1. the source of the water. 2. the type of soil. 3. bedrock and vegetation through which it travels. 4. the types of contaminants the water encounters in its path. 5. and even the amount of mixing and aeration due to turbulence in its flow. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06  the procedure: after calibration of the devise (meter), place the electrode into the water sample and record the ph using the ph meter shown in fig. (1).the glass electrode on these meters must be carefully rinsed with deionized water after each use to ensure accurate results. figure (1): ph meter 2.2. electrical conductivity test: this method is used to measure the electrical conductivity generated by various ions in the water. the electrical conductivity is the capacity of water to carry an electrical current and varies both with number and types of ions in the solutions, which in turn is related to the concentration of ionized substances in the water. most dissolved inorganic substances in water are in the ionized form and hence contribute to conductance. rough estimation of dissolved ionic contents of water sample can be made by multiplying specific conductance (in ms/cm) by an empirical factor which may vary from 0.55 to 0.90 depending on the soluble components of water and on the temperature of measurement.  the procedure: the conductivity meter often indicates conductivity directly as shown in fig. (2). commercial probes commonly contain a temperature sensor. with such instruments, rinse probe three times with 0.0100m kcl. adjust temperature compensation dial to 0.0191 c−1. with probe in standard kcl solution, adjust meter to read 1412 μmho/cm. this procedure automatically adjusts cell constant internal to the meter, [11] . figure (2): conductivity meter al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06 2.3. turbidity test: water turbidity is caused by suspended and colloidal matter such as clay, silt, finely divided organic and inorganic matter, and plankton and other microscopic organisms.  the procedure: • turbidity is an expression of the optical property that causes light to be scattered and absorbed rather than transmitted with no change in direction or flux level through the sample which is put in the clean beaker. • correlation of turbidity with the weight or particle number concentration of suspended matter is difficult because the size, shape, and refractive index of the particles affect the light-scattering properties of the suspension. when present in significant concentrations, particles consisting of light-absorbing materials such as activated carbon cause a negative interference. • in low concentrations these particles tend to have a positive influence because they contribute to turbidity. the presence of dissolved, color-causing substances that absorb light may cause a negative interference. some commercial instruments may have the capability of either correcting for slight color interference or optically blanking out the color effect using the meter shown in fig. (3). figure (3): turbidity meter 2.4. total suspended solids test: solid analyses are important in control of biological and physical water treatment processes and for calculate the strength of water .the more solids present in particle in water give strong waste water and cause putrefaction problems.  the procedure:  in this process, the beaker washes and dried in the oven.  use filtration papers of (102) moderate which placed in the beaker, then pour amount of (30 ml) of drinking water in the filtration beaker and wait till all amount of water get down to the beaker.  residues with filter paper dried at 103 °c to 105°c. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06  the difference between the weight of the filter paper (1.0280 g) before and after filtration represents the amount of total suspended solids as in equation (1), (apha, et. al. 2005).  calculations water with total suspended solids; it’s given by the equation: total suspended solids (tss mg /l) = (1) where: a is the weight of dried residue + filter paper (mg), b is the weight of filter paper (mg), and v is the volume of the sample (ml) 2.5. filtration process: the crushed waste glass was obtained from waste sheet glass (window glass-soda lime glass). glass objects were cleaned and then crushed manually and mechanically to get the required gradation. crushed glass was sieved to ensure completely uniform distribution of particle size. the particle size was (150 and 300) µm.  the procedure:  wash the crushed waste glass by clean water then dry it by oven.  use filtration papers which placed on the filtration flask, and put )10 g) of crushed glass on a cake filtration, in which the particles are removed on the surface of a cake formed by the solids accumulating on a septum  put the amount of (30 ml) drinking water on the crushed glass which is at filtration flask, and leave it for ten minutes. the process considered as a batch system.  wait until all the amount of filter water get down.  use the amount of filtered water to repeat the filtration procedures twice to determine tss accurately as shown in fig. (4). f figure (4): filtration process al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 09 results and discussion 1ph test: the ph measurements showed that the ph values were almost the same for all stations around (7) before and after filtration and were all in acceptable limit as shown in table (1) and fig.(5). the time for each test takes five minutes. 2electrical conductivity test: table (2) and fig. (6) show the values of the electrical conductivity for ten different samples of water before and after filtration. there is no difference between the values of electrical conductivity for each station before and after filtration, so they have the same values. it is noted that the conductivity values ranged from the maximum (1083)μs/cm at (madinat alsader)to the minimum (683)μs/cm at (almansoor),and other region are between these values . also, the time for each test takes five minutes. 3turbidity test: table (3) and fig. (7) express the values of the turbidity of ten different water samples before and after filtration and showed that most samples of water are acceptable except (madinat alsader) which was very high before filtration, that means this water unacceptable to use for drinking depending on iraqi standards as shown in appendix (1), but this value is reduced after filtration from (21.30 ntu to 10.0 ntu). the portable water sample of madinat alsader had large amount of suspended solids which were reduced after filtration process by using waste glass and this resulted to reduce the turbidity value for the same station. 4total suspended solids test before and after filtration process: table (4) and fig. (8) show the total suspended solids (tss) for ten different water samples before and after filtration. it shows that the tss values before filtration process were high in some regions that have been testing, it appeared less worthless in (althaalba) which was (0.3333) mg/l which makes this water acceptable to drink, but the highest values at (madinat alsader) was value (5) mg/l, other region between these values. after filtration process, the tss values showed a significant reduction in most regions especially in (althaalba and alameria) which disappeared and become (zero).that means, the process of filtration using waste glass was successful and it can be used to help in purification of potable water. the tss values for aldora and bab al moatham did not change before and after filtration process because of the small size of suspended particles which penetrate through the waste glass filter. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 00 conclusion the objective of this study is to investigate the effect of using crushed waste glass as coarse sand and filter in the treatment process to drinking water, where the results can be concluded as the following:  the process of using the recycling waste glass is successful to be as a water treatment component.  after testing the physical and chemical properties of the ten samples of drinking water, most of the stations of water are acceptable for drinking except the station of madinat alsader which was not acceptable depending on the iraqi standards.  after filtration treatment by waste glass, the drinking water were more acceptable to drink, the (tss) were less in some samples and the others were being zero (disappears) such as in althaalba and alameria.  so the process of using the recycling waste glass is an important method with many advantages such as:  saving energy reduces acid rain, global warming and air pollution.  saving the environment from waste glass.  saving the cost of the raw material.  it can be reused in many cases.  creates employment in the glass industry.  reduces operating waste disposal costs by reducing weight and volume of waste storage, transportation and disposal…etc. (1) ppendixa the iraqi standards of drinking water units of measurement concentration or value (maximum unless otherwise stated) parameters mg/l pt/co 15-20 color should be acceptable odor should be acceptable taste ntu 4-5 turbidity c˚ 9-15 temperature μs/cm 301-2000 conductivity 6.5-8.5 ph value mg/l it should be zero tss al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06 references: [1] apha, awwa, wef. (2005). standard methods for the examination of water and wastewaters, 21st edition .american public health association. washington dc [2] bccdc environmental health laboratory services (2006). safe drinking water: public health laboratory surveillance update. british columbia, canada. [3] a chin, david a. (1999), “water resources engineering”, prentice hall. [4] crook, j., ammermman, d.k., okun, d.a. and matthews, r.l. 1992 guidelines for water reuse. camp dresser & mckee, inc., cambridge, massachusetts. [5] diab, f, saleh, s & el-burai, s 2010, ‘recycled glass and its applications in construction’, b.sc graduation thesis, islamic university of gaza, palestine. [6] elif soyer1, o¨mer akgiray2, nursen o¨ z eldem1, ahmet mete saatc¸ı2 (2010). crushed recycled glass as a filter medium and comparison with silica sand. clean-soil, air, water, 38(10), 927-935. [7] finkle, i &ksaibati, k 2007, ‘recycled glass utilization in highway construction’, department of civil & architectural engineering, university of wyoming, wyoming, united states. [8] habayeb abdul al-hussein majid (2008). determining the extent of theagreement between modern paints company waste water and sewage and iraqi specifications. technical magazine / folder atheist twenty / number 4. [9] hach. 1997. hach water analysis handbook.3rd ed. hach company. loveland, co lamotte chemical products company. undated laboratory manual for marine science studies. lamotte educational products division, chestertown, md.41 pp. [10] hayder, m. arshad and j.a. aziz,(2009): "evaluation of drinking water quality in urban areas of case study of southern lahore pakistan" pak. j. eng. and appl. sci. vol. 5, pp (16-3). [11] healy, m.g., burke, p., rodgers, m. (2010). the use of laboratory sand, soil and crushed-glass filter columns for polishing domestic-strength synthetic wastewater that has undergone secondary treatment. journal of environmental science and health, part a: toxic/hazardous substances and environmental engineering 45(12) 1635-1641. [12] hem, j. d. (1970). study and interpretation of chemical characteristic of natural water.3rd ed. u. s. g. s. water supply paper 2254-263pp. [13] life water international (2004). water quality testing: a key to avoiding health risks simple test procedures for rural drinking water sources. life water international san luis obispo, usa. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06 [14] l. w. gill, p. l. veale, m. murray (2011). recycled glass compared to sand as a media in polishing filters for on-site wastewater treatment. published september,6(3)doi: 10.2166/wpt.2011.058. [15] metcalf, r.c., and d.v. peck. 1993. a dilute standard for ph, conductivity, and acid neutralizing capacity measurement. journal of freshwater ecology 8:67-72. [16] rafah. alsuhaili, awatif soaded a. alsaqqar, nawar omran ali nasser (2012). initial collection efficiencyfor glass filter media. number 2 volume 18 february journal of engineering. [17] river watch network. 1992. total alkalinity and ph field and laboratory procedures. (based on university of massachusetts acid rain monitoring project). [18] ronald l. droste, lstedition, 1997.theory and practice of water & waste water treatment. [19] shareef ,kafia, m., muhammad, suleiman, g. and shekhani, nazanin, m.,(2009) : “physical and chemical status of drinking water from water treatment plants on greater zab river “j. appl. sci. environ manage. vol.13 (3) 89 -92. [20] simon o. rutledge and graham a. gagnon (2002). comparing crushed recycled glass to silica sand for dual media filtration. j. environ. eng. sci. 1: 349–358. [21] unced 1992 chapter 18 protection of the quality and supply of freshwater resources. in: agenda 21. united nations conference on environment and development, geneva. [22] u.s.epa. 1995. quality management plan for wed. national health and environmental effects research laboratory. western ecology division, corvallis, or. [23] who 1993 guidelines for drinking-water quality. volume 1 recommendations. second edition. world health organization, geneva. [24] world health organization (1997). guidelines for drinking water quality, volume 3 surveillance and control of community supplies, geneva. [25] yulia zakharovacvysz, andrew wheatley (2008). treatment of urban runoff by filtration using a recycled glass medium. 11 t h international conference on urban drainage, edinburgh, scotland, uk. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 table (1): ph values ph. value the region sample no. 6.67 almansoor 1 7.08 alameria 2 6.99 madinatalsader 3 6.90 albaladiat 4 6.82 althaalba 5 7.03 alzaafarania 6 7.01 haifa street 7 7.17 aldora 8 7.02 alkathmia 9 7.04 bab al moatham 10 table (2): conductivity values conductivity value μs/cm the region sample no. 16˚c (683) almansoor 1 15.4˚c(784) alameria 2 16.2˚c(1083) madinatalsader 3 16.2˚c(982) albaladiat 4 16.1˚c(914) althaalba 5 16˚c(890) alzaafarania 6 16.2˚c(1035) haifa street 7 16.1˚c(960) aldora 8 16.1˚c(1010) alkathmia 9 16.1˚c(1034) bab al moatham 10 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 66 table (3): turbidity values turbidity value(ntu) after filtration turbidity value(ntu) before filtration the region sample no. 0.82 0.82 almansoor 1 0.58 0.58 alameria 2 10.0 21.30 madinatalsader 3 0.91 0.91 albaladiat 4 2.24 2.24 althaalba 5 3.91 3.91 alzaafarania 6 1.27 1.27 haifa street 7 5.0 5.04 aldora 8 2.45 2.45 alkathmia 9 0.97 0.97 bab al moatham 10 table (4): tss values before and after filtration process samples no. region name tss values before filtration(mg/l) tss values after filtration (mg/l) 1 almansoor 1.3333 0.333 2 alameria 1 0 3 haifa street 3 1.3333 4 aldora 1 1 5 alkathmia 2.333 1.6666 6 madinalalsader 5 3.6666 7 albaladiat 4 1.66666 8 althaalba 0.333 0 9 alzaafarania 3.3333 1 10 bab almoatham 0.666667 0.66666 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 66 figure (5): ph values for different baghdad districts figure (6): electrical conductivity values (μ s) for different baghdad districts 0 200 400 600 800 1000 1200 1400 e le ct ri ca l co n d u ct iv it y v a lu e s ( e c , μ s ) district al-karkh al-rusafa 6.4 6.5 6.6 6.7 6.8 6.9 7 7.1 7.2 7.3 p h v a lu e district al-karkh al-rusafa al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 66 figure (7): turbidity values (ntu) for different baghdad districts figure (8): tss values before and after filtration (mg/l) for different baghdad districts 0 5 10 15 20 25 t u rb id it y ( n t u ) district al-karkh al-rusafa 0 1 2 3 4 5 6 t s s v a lu e s (m g /l ) district tss befor filtration (mg/l) tss after filtration (mg/l) 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 34 الحكومية في المملكة العربية السعودية تشييدمشاريع ال إدارة على المؤثرة العوامل "انموذجأ المكتبية المبانيمشاريع تغيير أوامر" صالح خضر العطوي جامعة تبوك المملكة العربية السعودية 1122كانون االول 12ُقبل في 1122 تشرين الثاني21ًأستلم ص:خلم إدارة في ةالفاعل والرتغيرات العوارل أهم دأح باعتبارها ،التغيير واررأل وصفية ،استكشافية دراسة البحث هذا أوارر في الفاعلة ألطرافا على التعرف :وهي ،األهداف رن عدد تحقيقل الباحث سعى وقد ،التشييد رشاريع أوارر قيرة احتساب كيفية على التعرفو التغيير، أوارر في الفاعلة ألطرافا رساهرة درجة تحديدو التغيير، رن تؤثر التي الجوانب أهم على التعرفو التغيير، أوارر بها تحدث التي األعرال أهم وتحديد ورصد التغيير، ،ريدانية دراسة بإجراء الباحث قام السابقة األهداف قالتشييد. ولتحقي رشروعات إدارة على التغيير أوارر خاللها وطبق الرطلوبة، البيانات على للحصول االستبانة؛ أداة على اعترد كرا ،بالعينة الرسح رنهج على فيها اعترد الحكورية. الرباني تشييد حقل في العارلين رن رفردة 652 قوارها غرضية عينة على الريدانية دراسته أهرها: رن النتائج، رن لعدد الدراسة تخلص قدو التغيير. أرر عنده رن يبدأ الذي الطرف بوصفه األول الترتيب في الرشروع رالك جاء أرر قيرة احتساب في شيوعا األكثر الطريقة يعد ،األصلي العقد حسب البند سعر طريق عن االحتساب نأ التغيير. التغيير. أوارر تنفيذل رتبع كأسلوب ،األول الترتيب في يأتي الخطي التعريد لحين ،التنفيذ عن االرتناع أن للتنفيذ. قابال التغيير أرر جعل في فاعلية األكثر الطرف هو الرالك أن األخرى. العناصر كافة تفوق بدرجة التغيير أوارر فيه تتكرر الذي الرجال هي الرعرارية األعرال نأ .المكتبية الحكومية المباني ، أوامر التغيير،التشييد عير امش إدارة:رئيسية كلمات 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 33 the factors affecting public construction management in saudi arabia: "variation orders via office building as sample" saleh alatawi university of tabuk, ksa satawi@ut.edu.sa abstract : this research is an exploratory and descriptive study of the variation orders, as one of the most important issues and variables acting in saudi construction management. the researcher tried to achieve five objectives, which are: identifying the main active stakeholders in the variation orders, to determine to what extend they affect the variation orders, how the variation orders are priced, monitoring and identifying the most important activities that cause the variation orders, and to identify the most important aspects on how the variation orders affect the management of construction projects. to achieve the objectives above, the researcher conducted a field study, which relied on a sample survey approach to obtain the required data. the researcher applied the field study using 256 samples from the field of governmental construction management. the research found a number of results, of which:  the owner of the project was in the first place as the stakeholder that starts the variation orders.  original contract item pricing is the most common way to calculate the value of the variation orders.  to refrain from execution, while awaiting the written permitting comes in the first place, as a method of practice in the execution of variation orders.  that the project's owner is the most effective stakeholder that makes the variation order executable.  architectural works are most common cases in which the variation orders are repeated in a manner that is greater than all the other cases. keywords :construction management, variation orders, governmental office buildings. 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 34 مقدمة: رشروعات إدارة رجال في تطرح التي القضايا أهم رن واحد (variation orders) التغيير أوارر روضوع يعد بأوارر ويقصد ،والرالي والفني اإلداري الرستوى على يطرحها التي تاإلشكاال جرلة إلى ذلك ويعود ،التشييد عدوب كثيرة أحيان ففي ؛أو بهرا رعا اإلضافة أو بالحذف الرشروع عقد وثائق على يطرأ تغيير كل :التغيير تعديالت ثرة أن -الرستفيد أو الرالك يكون را الباوغ األطراف أحد يكتشف ،الرشروع تنفيذ في قدرا الرضي ويحدث ،التغيير بأوارر يسرى را تستوجب التعارض رن حالة أتنش وهنا ،الحسبان في أخذها رن بد ال إضافية رنها: لعل رتنوعة سبابأل نتيجة الغالب في األرر هذا ،التصريم ررحلة عرالأ إنهاء في لالستعجال نتيجة :التعاقدية المستندات في واالختالفات التعارضات .1 (günhan etall, 2007) .العقد وثائق جودة ضبط إجراءات وغياب تختلف وتطويرات تعديالت عو الرشر على يطرأ األحيان رن كثير في :المشروع مخططات وتعديل تطوير .6 (6002 ،)شعبان .رتعددة ألسباب ؛للرشروع صليةاأل اريملتصا عن في زيادة بطلب الرستفيد أو الرالك يقوم األحيان بعض في :بالمشروع امتدادات وأ عناصر زيادة طلب .3 .العقد وثائقفي عليها ارنصوص تليس ،جديدة ارتدادات وأ الرشروع أجزاء بعض ببنود بنودال بعض استبدال يتم األولى الحالة في :بنودال بعض deletion إلغاء أو replace استبدال .4 أراكن وأ ،خضراء برسطحات الرالك ررثل رؤية حسب استبدالها ويتم ،فارغة رناطق تكون نكأ ،خرىأ الرستندات في ورد ررا البنود بعض حذف يتم )اإللغاء( الثانية الحالة وفي .خدرية وحدات أو نتظارا (assaf and hejji, 2006) .التعاقدية وجه على الرشروعات إلدارة بالنسبة األهرية رنتهى في دورا ترارس التغيير أوارر بأن القول يركن هنا رن دارة ،العروم والردة بالتكلفة تتعلق اعتبارات رن عليها يترتب لرا ،الخصوص وجه على التشييد رشروعات وا .والجودة الزرنية على الضوء يتلق التي التساؤالت رن عدد على اإلجابة سيحاول الذي بحثال هذا فكرة جاءت ذلك ضوء في قطاع في التشييد رشاريع إدارة على تؤثر التي العوارل أهم أحد بوصفه التغيير أوارر لروضوع رختلفة جوانب .الركتبية الحكورية الرباني :سوغاتهومالبحث أهمية -أوال ضرن التشييد رشاريع إدارة على ثيرهابتأ يتعلق فيرا خاصة التغيير أوارر بروضوع الرعنية الدراسات قلة .1 السعودية. العربية الررلكةب الركتبية الحكورية الرباني رشاريع رن الكثير في رنها دُيستَفا أن ويركن ،أهرية ذات ستكون البحث هذا إليها يخلص أن يركن التي النتائج نأ .6 الركتبية. الحكورية الرباني برشروعات الصلة ذات الجهات خاصةوب ،والخاصة الحكورية الجهات .والرشكالت القضايا هذه حل في للتبحر الرستقبلية للدراسات فاقاآل الدراسة هذه تفتح سوف .3 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 34 :البحث مشكلة -ثانيا بروضوع الررتبطة الجوانب رختلف تلرس الباحث فيه سيحاول الذي ،الكشفي االستقصاء رن نوع البحث هذا العربية الررلكة في التشييد رشاريع إدارة على والرؤثرة الفاعلة الرتغيرات أهم أحد بوصفها التغيير؛ أوارر عودية.الس في التغيير أوارر لروضوع الرشّكلة الجوانب أهم را رؤداه: رئيس تساؤل في تتحدد البحث رشكلة فإن ذلك لىوع فيه يتحرك سوف الذي العام اإلطار هو التحليلي الوصفي الطابع إن. الركتبية؟ الحكورية الرباني تشييد إدارة صورة إلى )حقليا( ريدانيا وبحثها رناقشتها رن نخلص التي االقضاي رن عدد إثارة خالل رن الراهن، البحث التشييد. رشروعات إدارة ضرن فيه الفاعلة واألطراف التغيير أوارر واقع عن الرعالم واضحة البحث أهداف -ثالثا ،التغيير أوارر لروضوع الرشكلة الجوانب أهم وتحليل وصف رحاولة في البحث لهذا العام الهدف يترثل األهداف رن رجروعة ثرة العام الهدف هذا رظلة وتحت التشييد، رشاريع إدارة على وفاعال رؤثرا بوصفه :ةاآلتي الجوانب لرعرفة تسعى الفرعية التغيير. أوارر في الفاعلة األطراف التغيير. أوارر قيرة احتساب كيفية التغيير. أوارر في الفاعلة األطراف رساهرة التغيير. أوارر بها يحدث التي األعرال أهم التشييد. رشروعات إدارة على التغيير أوارر خاللها رن تؤثر التي الجوانب أهم التغيير واررأ جوانب تشكيل في الخبرة( سنوات ،التشييد رنظورة رن )الروقع الوسيطة الرتغيرات بعض دور حصائي.اإل الرنهج باستخدام للبحث: النظري اإلطار -رابعا البحث: مصطلحات -2  التغيير أوارر variation orders التعاقد( )رستندات العقد وثائق على تحدث تبديالت أو تعديالت أو تغييرات أي :التغييرية باألوارر الرقصود ،سراعيلإ) .الرشروع في رواصفاتها أو كرياتها أو نوعها أو األعرال شكل في ضرورية الحكورية الجهة تراها 6014) والعريل الرقاول بين الربرم العقد على تطرأ تعديالت أي بأنها التغيير أوارر (ndihokubqayo, 2008) عرف عنه. ينوب رن أو 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 34 والرقاول الرالك قبل رن مالربر العقد نصوص في تبديل بأنه التغيير أرر (günhan etall, 2007) عرف كرا نصوص في الرراجعة أو اإلضافة أو بالحذف يكون التبديل وهذا الرشروع، بتنفيذ الخاصة التفاصيل بعض في .العقد البدء بعد الرقاول أو الرالك قبل رن يصدر كتابي أرر بأنه التغيير أرر (al-dubaisi, 2000) عرف أيضا في تغييرات عن فضال ،الزرنية الردة أو العقد ربلغ في تعديال أو العرل في اتغيير يجيز ،العقد تنفيذ في العقد. رستندات وباقي والتصريرات الرسورات جراء لتصحيح الرشاريع بناء على تطرأ التي التغييرات بأنها التغيير أوارر (alnuaimi etall, 2010) عرف وا للرشروع. األصلي التصريم على التعديالت بعض  أخرى: رصطلحات الرشروع. صاحب الحكوري القطاع رظلة تحت الهندسية دارةاإل الرالك: الحكوري القطاع رظلة تحت الحقا رنه وتستفيد الرشروع تستخدم سوف التي الجهة :ةالرستفيد الجهة الرشروع. صاحب الرشروع. تنفيذ عن ةالرسؤول الرؤسسة وأ الشركة الرقاول: العقد. وثائق رعظم جنت يُ غالباو ،الرشروع رصرم التصريم: استشاري التنفيذ. على اإلشراف في الرالك عن ينوب رن اإلشراف: استشاري حالة في الرشروع صاحب الحكوري القطاع عن ينوب رن وهو ،الرشاريع إدارة استشاري اإلدارة: استشاري القطاعات بعض قبل رن التشييد رنظورة ضرن رؤخرا إدخاله تم ،ةيالهندس اإلدارة كفاية عدم وأ وجود عدم .الحكورية :السابقة الدراسات -1 رصدت وقد ،األرريكية كنتاكي بوالية الطرق رشروعات في التغيير أوارر حول (taylor etall, 2012) دراسة بصرف الخاصة التجهيزات رنها: البحث رنطقة في الطرق بناء برشاريع الررتبطة التغيير أوارر أهم الدراسة على األران رتاريسو ،للصدرات الواقية الحواجزو للسيارات، الطارئ الوقوف أراكنو الدهان، أعرالو الرياه، ةياإلضاف التكلفة أن النتائج كشفت وقد للصوت. العازلة الجدرانو واإلشارات، ضاءةاإل وعالرات الطريق، جانبي األصلية. الرشروع قيرة رن %35.52 إلى %2.36 بين را تراوحت التغيير أوارر تنفيذ عرلية هاطلبتت التي العربية الررلكة في التحية البنية رشروعات في التغيير أواررب الخاصة (ibn-homaid etall, 2011) دراسة أوارر عن الرسؤول األول الطرف هو االستشاري أن رنها: النتائج رن لعدد الدراسة خلصت وقد ،السعودية 11 أيضا النتائج أوضحتكرا %،10 %إلى2 بين را تتراوح األوارر هذه بسبب زائدة تكلفة هناك وأن التغيير، الخاصة تغييراتوال الرالك، قبل رن طلبات ضافةإ بسبب الرشروع نطاق تغيير رنها: التغيير أوارر لحدوث اسبب بالتصريم. الرتعلقة الخاطئة أو الناقصة الرعلوراتو الجيولوجي، الرسح كفاية عدم بسبب التصريمب 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 34 سلطنة في الحكورية الرشروعات في التغيير أوارر عن الناجرة التأثرات عن (alnuaimi etall, 2010) دراسة وخلصت الدراسة إلى أن أوارر التغيير ،الحكورية الرشروعات رن نراذج ةأربع العرل فريق شخص وقد ،عران رن البحر، رياه تحلية لرحطة الرئيسة األنابيب خطوط رسار بتغيير طلبات -1التي تم الكشف عنها تترثل في: كم، 64 نحو تعبيد -3 ،عدد رن الركاتب والرختبراتإضافة -6,الخاصة والحدائق الرنازل عبر األصلي رساره %10 نحو التغيير أوارر تكلفة بلغت وقد اإلنشاء. ثناءأ الررور حركة لتحويل رؤقت طريق ءإنشا اقتضت والتي .ةاألصلي العقود قيرة رن دراسة بإجراء الباحث قام وقد الرشروع، أداء على التغيير أوارر تأثير عن (ndihokubwayo, 2008) دراسة التغيير أوارر أن إلى نتائجها في الدراسة خلصت وقد ،رتروبوليتان كيب ويسترن في ةعارل شركة نلثالثي حالة الرتفق الربالغ إلى نسبة التكلفة في قليلة غير زيادة عن فضال ،اتللرشروع الرقررة الردة في تأخير عنها نجم العقد. أطراف بين االختالفات رن الكثير األوارر هذه عن نجم كرا األساسية، العقود في عليها رباني تنفيذ في التغيير أوارر عن الناجرة الزائدة التكلفة تجنب كيفية عن (günhan etall, 2007) دراسة األرريكية، حياءاأل أحد في الردارس رن بعدد الرتعلقة التغيير أوارر بتحليل الباحث قام الحكورية، الردارس الرشار الفترة نهاية في التغيير أوارر بسبب ؛الرضافة القيرة في التراجع رن نوع حدوث إلى الدراسة وخلصت كان التصريم في السهوو خطاءاأل أن أيضا النتائج كشفتكرا %،4.24 إلى %5..2 رن ببدايتها رقارنة إليها .التغيير أوارر حدوث في األكبر الدور لها ،السعودية العربية الررلكة في الكبرى الرشاريع في التأخير أسباب حول (assaf and hejji, 2006) دراسة التأخير عرلية في الرئيس السبب أنو ،الرقاولين إلى تعود التأخير أسباب رن %52 أن إلى الدراسة وخلصت 62 بين فرن %،60 نحو البحث رحل الرشروعات في األوارر هذه نسبة بلغت حيث التغيير أوارر إلى يعود األوارر. تلك بسبب الزرنية الردة تتجاوز رشروعا 45 هناك رشروع قام وقد ،العرل إنتاجية على اإلنشاء رشروعات في التغيير أوارر تأثير عن (moselhi etall, 2005) دراسة وقد األرريكية. الرتحدة والواليات كندا رن كل في ارشروع 33 شرلت بيانات ورراجعة بفحص العرل فريق ساعات رن تفرضه لرا العرل، إنتاجية على السلبي التأثير في تتسبب التغيير واررأ أن إلى الدراسة خلصت الجودة رستوى في تدن بالفعل عنها ينجم التغيير ررأوا نأ هي للدراسة أهرية األكثر لنتيجةوا إضافية، عرل .الرشروع داخل الكفاءةو انصب وقد السعودية، العربية الررلكة في البناء رشاريع في التغيير أوارر عن (al-dubaisi, 2000) دراسة أن رنها: النتائج رن عدد لىإ الدراسة خلصتو عنها، الناجرة والتأثيرات التغيير اوارر أسباب على االهترام العقد قيرة رن %10% / 2 بين را التكلفة في زيادة عنها نجم قد الدراسة رحل الرشروعات في التغيير أوارر األصلية. الرشروع ردة رن %10 رقدارها زيادة عن فضال األصلي، 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 34 السابقة: الدراسات خريطة من الراهنة الدراسة موقع والدولي الرحلي الرستوى على التغيير أوارر روضوع حول أجريت التي الدراسات لبعض السابق العرض رن التالي: النواحي في السابقة الدراسات عن يتريز الراهن بحثنا روضوع بأن القول يركن الركتبية. الحكورية الرباني وهي األبنية رشروعات رن رحددة نوعية على تركيزه -1 الشفوية، التغيير أوارر تنفيذ ررونة ردى رثل: السابقة الدراسات إليها تتطرق لم قضاياو روضوعات ثارةإ -6 الجودة. على التغيير واررأ تأثيرو ،التغيير أوارر اعتراد في الفاعلة طرافواأل الصغر، في رتناهية أو صغيرة عينات إرا فهي ؛الرستخدرة العينات حجم بصغر السابقة الدراسات اتسرت -3 في اعتردت السابقة الدراسات أيضا الحجم. حيث رن رتوسطة عينة على الدراسة هذه اعتردت حين في الراهنة الدراسة دخلتأ حين في فقط، الرالكة والجهات واالستشاريين الرقاولين شريحة على عينتها ركونات الرستفيدة. والجهات اإلدارة، استشاري في اترثلت ثانيتين يحتينشر المنهجية: اإلجراءات-خامسا فيها قلت التي الروضوعات رن نعده أن نيرك البحث رحل الروضوع أن إلى بالنظر :البحث منهج -1 ورن ثم فقد البحثية، الرحاولة تلك يسم الذي هو الكشفي الطابع فإن ،السعودي الواقع في السابقة الدراسات الكشفية الدراسات في الرستخدرة الرناهج أهم أحد بوصفه ،بالعينة الرسح على رنهج الباحثاعترد .التحليلية الوصفية والدراسات ررت ،استبانة بتصريم الباحث قام حيث ،ةاناالستب أداة على أساسي بشكل باحثال اعترد :البحث أداة -6 اآلتية: بالرراحل تصريرها عرلية ذات لروضوعات تتطرق الذي ةالسابق الدراسات رن الباحث استفاد وقد :األولي شكلها في االستبانة وضع . أ خبرة رن مله لرا التشييد رشروعات إدارة رجال في العارلين رن الباحث استفاد كرا البحث، بروضوع صلة الرجال. هذا في رجال في العارلين رن رحكرين 5 عدد على االستبانة بعرض الباحث قام المحكمين(: )صدق األداة صدق . ب عليها الرحكرين اتفاق نسبة بلغت التي سئلةواأل العبارات على الباحث أبقى قدو التشييد، رشروعات إدارة فأعلى. 50% (30) عدد على االستبانة تطبيقتم حيث اإلعادة، طريقة رن خالل األداة ثبات رن التأكد تم :األداة ثبات . ت طريق وعن يورا، عشر خرسة ررور بعد نفسها العينة على لالختبار توزيعها عيدوأ الدراسة رفردات نر جيد رعدل نهأ يعني وهذا 45..0 الثبات رعدل لغب ،(cronbach alpha) كرونباخ ألفا رعارل حساب الدراسة. عينة على وتطبيقها النهائية صياغتها في االستبانة وضع تم ذلك ضوء وعلى (6003)سلطان, بدرجة تترتع االستبانة هذه أن الرؤكد رن أصبح األداة ثبات رن التأكد بعد :النهائي شكلها في االستبانة . ث .عليها الحصول سيتم التي النتائج في الوثوق ويركن ،الثبات رن عالية 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 45 بسحب وقام حترالية(إ)الال الغرضية الرعاينة أسلوب على الباحث اعترد :خصائصها وأهم البحث عينة -3 الذهاب خالل رن وذلك ،العينة رفردات لسحب الريسرة الطريقة الباحث واستخدم ،رفردة 652قوارها عينة وفيرا يلي أهم خصائص عينة العرل. ورواقع الحكورية اإلدارات في البحث جرهور وجود اكنأر إلى رباشرة :(2كما يوضحها جدول رقم )البحث الرقاولين، رن %40.2 اآلتي: النحو على التشييد رنظورة رن الروقع حسب البحث عينة أفراد يتوزع . أ %3.5و الرالك، رن %13.3و الرشاريع، إدارة استشاري رن %16.6و اإلشراف، استشاري رن %61.5و الرشروعات. رن الرستفيدة الجهات ررثلي رن %3.1 وأخيرا التصريم، استشاري رن خبرتها سنوات تتراوح العينة إجرالي رن %..36 اآلتي: النحو على الخبرة سنوات حسب العينة أفراد يتوزع . ب الذين أرا سنوات، عشر عن خبرتها تقل %1..6 أن حين في سنة، عشرين رن وأقل سنوات عشر بين را سنوات تزاد الذين وأيضا %،15.5 نسبتهم بلغت فقد والثالثين العشرين بين را خبرتهم سنوات تراوحت %.15.5 نسبتهم بلغت سنة الثالثين عن خبرتهم العينة توزيع بين (0.01) داللة رستوى عند إحصائية داللة ذات عالقة وجود تبين 6كا اختبار باستخدام . ت الخبرة سنوات تركزت حيث ،(365..3=6كا )قيرة الخبرة سنوات عدد وبين التشييد رنظورة رن الروقع على %15.6 بنسبة الرقاولين وفئة %..31 بنسبة الرشاريع إدارة استشاري فئة في سنة الثالثين عن تزيد التي األخرى. الفئات بباقي رقارنة حصائيةاإل الحزم لبرنارج وفقا الدراسة رفردات رعالجة ترت :البحث في المستخدمة اإلحصائية األساليب -4 التالية: حصائيةاإل الرعالجة أساليب استخدم تم حيث (spss) االجتراعية للعلوم الرتغيرات. بين االرتباطات لقياس االرتباط رعارل على جاباتاإل وكذلك التغير، وأرر الرتغيرات ببعض الرتصلة الفروق الستخراج التباين تحليل )ف( اختبار الدراسة. تساؤالت الدراسة. رتغيرات بعض بين رعنوية عالقة هناك نأ إلى يشير والذي كاي( )رربع التجانس جداول استخدام التالي: النحو على الحسابي الوسط قياس سيتم حيث الخراسي ليكرت رقياس استخدام التالي: النحو على (weights) وزان()األ القيم تدخل را عادة فإنه خرسة رن واحد اختيار هي جاباتاال نأ برا يالرأ بكثرة يحدث غالباً يحدث حياناً أ حدثي يحدث ال مطلقاً يحدث ال بشدة وافقأ وافقأ محـايد رفضأ بشدة رفضأ 5 2 3 1 2 وزاناأل الميدانية الدراسة نتائج -سادسا التغيير أوامر في الفاعلة األطراف -2 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 45 حيث ،األطراف الفاعلة في أوارر التغيير (1كما توضحها بيانات جدول رقم )أوضحت نتائج الدراسة الريدانية المقاول الثانية الررتبة في ويأتي ،(1.036) رعياري وبانحراف (.3.6) برتوسط المالك ولىاأل الررتبة في جاء (3.36) برتوسط المستفيدة الجهة تجاء الثالثة الررتبة وفي (،0.5.1) رعياري وبانحراف (3.41) برتوسط يعيار ر وبانحراف (.6.5) برتوسط شرافاإل استشاري جاء الرابعة الررتبة وفي (،1.026) رعياري وبانحراف يعيار ر وبانحراف (5..6) برتوسط المشاريع دارةإ استشاري جاء خيرةواأل الخارسة ةالررتب وفي (،.1..0) (0...6.) التغيير أوامر قيمة احتساب طرق -1 أوارر قيرة حتسابال طرق أن هناك أربع (3كما توضحها بيانات جدول رقم )كشفت نتائج الدراسة الريدانية (5..3) برتوسط األصلي العقد حسب البند سعر طريق عن االحتساب ولىاأل الررتبة في جاء حيث ،التغيير (3.30) برتوسط الربح إليها رضافا الحقيقية التكلفة طريقة الثاني الترتيب في يليه ،(1.114) رعياري وبانحراف برتوسط البند سعر إلى رنسوبة التفاوض ةطريق جاءت الثالث الترتيب وفي ،(1.060) رعياري وبانحراف التفاوض بعد تحديده تم سعر طريقة جاءت واألخير الرابع يبالترت وفي ،(0.566) رعياري وبانحراف (3.62) .(1.1.5) رعياري وبانحراف (3.60) برتوسط احتساب طريقة وبين التشييد رنظورة رن الروقع حسب العينة أفراد توزيع بين عالقة هناك كان إذا عرا ولرعرفة األصلي العقد حسب البند سعر طريقة رجحت الرستفيدة والجهة الرالك رن كال أن تبين التغيير، أوارر قيرة تحديده تم سعر طريقة رجحا الرشاريع إدارة واستشاري التصريم استشاري أن حين في ،األخرى الطرق باقي على (.4جدول رقم ) بيانات توضحه را وهو ،التفاوض بعد شفوي بتوجيه التغيير أوامر تنفيذ -3 على للتعرف وذلك ،(خطي تعريد بدون) شفوي بتوجيه تنفذ التي التغيير أوارر حول سؤاال االستبانة تضرنت كما توضحها بيانات جدول رقم وقد كشفت النتائج الريدانية التغيير، أوارر تنفيذ في )والرسرية( الررونة درجة ( وبانحراف رعياري .3.3الترتيب األول برتوسط )أن االرتناع عن التنفيذ لحين التعريد الخطي يأتي في (5) ، 1.021( وبانحراف رعياري 3.31(، يليه في الترتيب الثاني التغييرات ذات القيرة الرحدودة برتوسط )1.033) ( وبانحراف رعياري 1..6وفي الترتيب األخير جاءت التغييرات ضرن أنشطة الرسار الحرج برتوسط ) (1.120.) وقفهار في التشييد رنظورة رن روقعها حسب العينة فئات بين إحصائية داللة ذات فروق هناك كان إذا ولرعرفة (،anova) االتجاه أحادي التباين تحليل اختبار الباحث استخدم الشفوي، بالتوجيه ذتنف التي التغيير أوارر رن يلي: را (6كما توضح بيانات جدول رقم ) وقد كشف االختيار االحصائي  في التشييد رنظورة رن روقعها حسب الدراسة لعينة الرختلفة الفئات بين حصائيةإ داللة ذات فروق توجد ال جاءت حيث (،الرحدودة القيرة ذات )التغييرات بعد على شفوي بشكل تتم التي التغيير أوارر لتنفيذ تقديراتها دالة. غير "ف" قيم جريع 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 45  حسب الدراسة لعينة الرختلفة الفئات بين (0.05) بلغ رعنوية رستوى عند إحصائية داللة ذات فروق توجد( أنشطة ضرن )التغيرات بعد على شفوي بشكل ذتنف التي التغيير ألوارر ديراتهاتق في التشييد( رنظورة رن روقعها التالي: النحو الحرج( الرسار الرالك. لصالح التصريم واستشاري الرقاول رن كل وبين جهة رن الرالك بين تباين يوجد الرستفيدة. الجهة لصالح الرستفيدة الجهة وبين الرقاول بين تباين يوجد  في التشييد رنظورة رن روقعها حسب الدراسة لعينة الرختلفة الفئات بين احصائية داللة ذات فروق توجد ال "ف" قيم جريع جاءت حيث (،التنفيذ عن )االرتناع بعد على شفوي بشكل التي التغيير ألوارر لتنفيذ تقديراتها دالة. غير التغيير أوامر اعتماد -2 وقد كشفت نتائج الدراسة الريدانية نافذا ، أررا التغيير أرر رن تجعل التي الجهة حول سؤاال االستبانة تضرنت الجهة بوصفه الرالك رجحت %(..43) البحث عينة أفراد رن الغالبة النسبةأن (7كما يوضحها جدول رقم ) واستشاري والرقاول الرالك رن كل إلى %13.3 أشار حين في نافدا، ليصبح التغيير أرر اعتراد يركنها التي بعض هناك ذلك جانب إلى %،10.6 بنسبة اإلشراف واستشاري الرالك إلى أشاروا الذين يليهم الرشاريع، إدارة رتدنية. نسبة على حصلت الترجيحات التغيير أوامر بها يحدث التي األعمال -5 وتوضح التغيير، أوارر حدوث بها يتكرر التي األعرال عن سؤاال االستبانة الباحث يضرن أن الرهم رن كان تقديرات أفراد عينة البحث لتلك األعرال، ويتضح رن هذه البيانات أن األعرال ( 2بيانات الجدول رقم ) ترتيب الثاني جاءت أعرال التصريم الداخلي (، وفي ال.3.5الرعرارية جاءت في الترتيب األول برتوسط قدره ) (، وفي الترتيب الرابع جاءت 3.62(، وفي الترتيب الثالث جاءت األعرال الكهربائية برتوسط )3.51برتوسط ) (، وفي الترتيب الخارس جاءت أعرال التصاريم والرخططات برتوسط 3.60األعرال الريكانيكية برتوسط ) (، وفي الترتيب السابع جاءت األعرال 3.56اءت أعرال التأثيث برتوسط )(، وفي الترتيب السادس ج3.25) (.3.66(، وفي الترتيب الثارن واألخير جاءت أعرال البنية التحتية برتوسط ).3.4الردنية برتوسط ) وألن األعرال الرعرارية احتلت الررتبة األولى بوصفها الرجال األكثر عرضة ألوارر التغيير فقد اهتم الباحث برعرفة عرا إذا كانت هناك عالقة بين توزيع أفراد العينة حسب الروقع رن رنظورة التشييد وبين تقديراتهم لهذا تبين عدم وجود (9ا توضح بيانات جدول رقم )وكم ( 60.441= 6)قيرة كا 6باستخدام اختبار كاو الرجال، عالقة بين توزيع أفراد العينة حسب روقعهم رن رنظورة التشييد وبين تقديراتهم لكون األعرال الرعرارية هي الرجال األكثر عرضة ألوارر التغيير، وهو را يعني أن ثرة توافقا داخليا بين آراء أفراد العينة تجاه هذا التقدير. :التشييد مشروعات إدارة على التغيير أوامر خاللها من تؤثر التي نواتالق أهم -6 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 المشروع وتأخير التغيير أوامر . أ التشييد، رشروعات إدارة على تأثيرها التغيير واررأ ترارس خاللها رن التي القنوات أهم على الباحث ركز الدراسة نتائج يوضح( 21رقم ) والجدول الرشروع، تأخير في ويترثل الزرن بعنصر خاص األول والرؤشر % رن إجرالي عينة البحث توافق بشدة على أن أوارر التغيير يترتب عليها 23.3، حيث اتضح أن الريدانية %، أرا 6%، وبلغت نسبة الرحايدين 62.2تأخير في الرشروع، في حين بلغت نسبة الذين أشاروا بالروافقة فقط %.1.2%، وأخيرا بلغت نسبة الذين أشاروا بالرفض بشدة 1.2نسبتهم الذين أشاروا بالرفض فبلغت ( 22رقم ) وتوضح بيانات جدول رقم وينجم عن تسبب أوارر التغيير في حدوث تأخير للرشروع لوقت إضافي، ا ورنهتقديرات العينة لرقدار الوقت اإلضافي الذي تتسبب فيه أوارر التغيير نسبة إلى الردة األصلية للرشروع، % رن إجرالي حجم العينة أشارت إلى أن إنجاز أوارر التغيير يحتاج إلى وقت إضافي رقداره 33.2أن يتبين أشاروا إلى أنه 15..6رن عشرة إلى أقل رن عشرين في الرائة رن الوقت األصلي للرشروع، في حين أن لى أنه يحتاج إلى وقت را بين % إ60.3يحتاج إلى وقت را بين خرسة إلى أقل رن عشرة بالرائة، كرا أشار %، وتساوت نسبة الذين أشاروا 5% إلى أنه يحتاج لوقت يقل عن 6عشرين وأقل رن ثالثين بالرائة، بينرا أشار % 40إلى أنه يحتاج لوقت را بين ثالثين وأقل رن أربعين في رائة والذين أشاروا إلى أنه يحتاج لوقت يزيد عن % لكل رنهم على حدة.5.5بواقع المشروع تكلفة وزيادة التغيير أوامر . ب الرشروع، تكلفة زيادة في التسبب في تترثل الرشروع إدارة على التغيير أوارر خاللها رن تؤثر التي الثانية القناة توافق العينة حجم إجرالي %رن53.5 أن( 16حيث كشفت النتائج الريدانية كرا توضح بيانات الجدول رقم ) نسبة وبلغت %،33.2 بالروافقة أشار حين في الرشروع، تكلفة زيادة في تتسبب التغيير أوارر أن على بشدة ذلك ويعني بشدة. أرفض اختيار إلى العينة أفراد رن أي يشر لم بينرا %،3.1 والرافضين %،5.4 الرحايدين الرشروع. تكلفة بزيادة التغيير أوارر فيه تتسبب الذي الدور على العينة أفراد بين كبير جراعإ ثرة نأ ، الذي يشير الى (23رقم ) الجدول فيوضحها للرشروع األ صلية القيرة إلى نسبة التغيير عرالأ تكلفة عن أرا % رن إجرالي حجم العينة أشاروا إلى أن أوارر التغيير تتسبب في زيادة التكلفة برا قيرة ) أكثر رن 42.5أن % أشاروا إلى أن هذه الزيادة تتراوح را بين 36في حين أن %( رن القيرة األصلية للرشروع، 10وأقل رن 5 % 60% إلى أن هذه الزيادة تتراوح را بين )أكثر رن 16.5%( ، هذا بينرا أشار 60% وأقل رن 10)أكثر رن %(، 40% وأقل رن 30% إلى أن هذه الزيادة تتراوح را بين )أكثر رن 5.5%( ، كرا أشار أيضا 30وأقل رن % بواقع 40% والذين أشاروا إلى أنها تزيد عن 5لذين أشاروا إلى أن هذه الزيادة تقل عن وتساوت نسبة ا % رن إجرالي حجم العينة 53.1% رن إجرالي حجم العينة لكل رنهم على حدة. برعنى آخر نجد أن 1.2 لرشروع األصلية.% رن تكلفة ا10أشاروا إلى أن أوارر التغيير تتسبب في زيادة تكلفة الرشروع بنسبة تزيد على 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 43 المشروع وجودة التغيير أوامر ج. نتائج يوضح( 22رقم ) والجدول الرشاريع، جودة على التغيير أوارر تأثير ردى حول سؤاال االستبانة تضرنت % رن إجرالي حجم عينة البحث أشارت بالروافقة بشدة 26.6، حيث اتضح أن الشأن هذا في الريدانية الدراسة %، 61.1التغيير ترارس تأثيرا على جودة الرشاريع، في حين بلغت نسبة الذين أشاروا بالروافقة على أن أوارر %، بينرا بلغت نسبة الذين رفضوا وبشدة هذا الرأي 6.3%، ونسبة الرافضين ..6وبلغت نسبة الرحايدين د عينة البحث توافق % فقط رن إجرالي حجم العينة. ورن هنا يركن القول بأن الغالبية العظرى رن أفرا1.2 على الرأي القائل بأن أوارر التغيير رن شأنها التأثير على جودة الرشاريع. حيث تظهر بيانات (،25جدول رقم ) فيوضحها إيجابية، أم سلبية كانت ذاإ عرا التأثيرات تلك طبيعة وحول على إيجابي تأثير لها التغيير أوارر أن إلى أشارت %(2..2) البحث عينة أفراد رن ىالعظر النسبة أن الجدول نسبة تركز أيضا البيانات توضح االتأثير. كر هذا سلبية إلى أشارت %31.4 أن حين في الرشروعات، جودة في أيضا، %66.5 الرقاولين وفئة %22.6 بنسبة الرالك فئة في التغيير ألوارر اإليجابي بالتأثير أشاروا الذين .%22.6 بنسبة الرستفيدة الجهة فئة في التغيير ألوارر السلبي بالتأثير أشاروا الذين نسبة تركزت حين الخالصة: األسئلة: تلك رن سؤال كل نع لإلجابة روجزة خالصة يلي وفيرا أساسية، تساؤالت ست البحث هذا طرح يحتل الرشروع رالك أن الريدانية الدراسة نتائج كشفت التغيير أوارر في ةالفاعل باألطراف يتعلق فيرا -1 استشاري ثم الرستفيدة، الجهة ثم الرقاول يليه التغيير، أرر عنده رن يبدأ الذي الطرف بوصفه األول الترتيب ظل في الرنطقي ترتيبال هو السابق والترتيب الرشاريع. إدارة استشاري جاء األخير الترتيب وفي اإلشراف فهو التغيير، أوارر برسألة األول الرعني هو فالرالك ،السعودية العربية الررلكة في للرشاريع الحالية الظروف رن األحيان بعض في يطلبه لرا نتيجة التغيير أوارر حدوث في يتسبب الغالب في الذي الطرف أو الجهة الرنشأة. في وتعديالت تغييرات إحداث البند سعر طريق عن االحتساب األول الترتيب في جاء ،التغيير أوارر قيرة احتساب بكيفية يتعلق فيرا -6 الثالث الترتيب وفي ،الربح إليها رضافا الحقيقية التكلفة طريقة جاءت الثاني الترتيب وفي ،األصلي العقد حسب زيادة ضرن تتركز التغيير أوارر رعظم نأ على ذلك ويدل البند. سعر إلى رنسوبا التفاوض طريقة جاءت .الكريات( في )نقص الرنافسة قبل العقد وثائق جودة ضبط وعدم خلل على يدل ررا ؛العقد كريات التشييد رنظورة رن الروقع حسب العينة أفراد توزيع بين عالقة هناك نأ اإلحصائية االختبارات كشفت وقد -3 سعر طريقة رجحت الرستفيدة والجهة الرالك رن كال أن تبين حيث التغيير، أوارر قيرة احتساب طريقة وبين الرشاريع إدارة واستشاري التصريم استشاري أن حين في األخرى، الطرق باقي على األصلي العقد حسب البند رنظورة رن الروقع )رتغير الوسيطة الرتغيرات أن يعني را وهو التفاوض، بعد تحديده تم سعر طريقة رجحا التغيير. أوارر جوانب تشكيل في ادور تؤدي التشييد( 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 التعريد لحين التنفيذ عن االرتناع أن النتائج كشفت فقد الشفوي بالتوجيه التغيير أوارر تنفيذب يتعلق فيرا -4 يركن التغيير أوارر رن ضئيلة نسبة هناك ان وجد حين في .الرشاريع رعظم في تُنتهج التي السرة هي الخطي الحرج. الرسار أنشطة ضرن والتغييرات الرحدودة، القيرة ذات التغييرات وهي ،شفوي بتوجيه تنفيذها أثبت فقد التغيير، أوارر جوانب تشكيل في (التشييد رنظورة رن )الروقع الوسيطة الرتغيرات بدور يتعلق وفيرا أنه: الشفوية وارراأل بتنفيذ يتعلق فيرا (anova) االتجاه حاديأ التباين تحليل اإلحصائي االختبار  في التشييد رنظورة رن روقعها حسب الدراسة لعينة الرختلفة الفئات بين حصائيةإ داللة ذات فروق وجدت ال قيم جريع جاءت حيث (،الرحدودة القيرة ذات )التغييرات بعد على شفوي بشكل التغيير أوارر لتنفيذ تقديراتها دالة. غير "ف"  حسب الدراسة لعينة الرختلفة الفئات بين (0.05) بلغ رعنوية رستوى عند إحصائية داللة ذات فروق توجد( أنشطة ضرن )التغيرات بعد على شفوي بشكل ذتنف التي التغيير واررأل تقديراتها في التشييد( رنظورة رن روقعها التالي: النحو الحرج( الرسار الرالك. لصالح التصريم واستشاري الرقاول رن كل وبين جهة رن كالرال بين تباين يوجد الرستفيدة. الجهة لصالح الرستفيدة الجهة وبين الرقاول بين تباين يوجد  في التشييد رنظورة رن روقعها حسب ،الدراسة لعينة الرختلفة الفئات بين حصائيةإ داللة ذات فروق توجد ال غير "ف" قيم جريع جاءت حيث (،التنفيذ عن )االرتناع بعد على شفوي بشكل التي التغيير أوارر لتنفيذ تقديراتها دالة. رن الغالبة النسبة أن الريدانية الدراسة نتائج كشفت ،التغيير أوارر اعتراد في ةالفاعل باألطراف يتعلق فيرا -5 في ،انافذ ليصبح التغيير أرر اعتراد هايركن التي الجهة بوصفه الرالك رجحت %(..43) البحث عينة أفراد الرالك إلى أشاروا الذين يليهم ،الرشاريع إدارة واستشاري والرقاول الرالك رن كل إلى %13.3 أشار حين القطاع ضرن للرشاريع الحالية الظروف ظل في رنطقي ارر وهذا %،10.6 بنسبة اإلشراف واستشاري اتخاذ تأخير يفسر وهذا اإلدارة، استشاري او الرشرف لالستشاري صالحيات يفوض ال فالرالك الحكوري التغيير. أوارر إجازة ضرنها ورن القرارات الرعرارية األعرال أن الريدانية الدراسة نتائج كشفت فقد ،التغيير أوارر فيها تتكرر التي األعرال عن أرا -2 برتوسط الداخلي التصريم أعرال جاءت الثاني الترتيب وفي ،(.3.5) قدره برتوسط األول الترتيب في جاءت األعرال تجاء الرابع الترتيب وفي ،(3.62) برتوسط الكهربائية األعرال جاءت الثالث الترتيب وفي ،(3.51) ،(3.25) برتوسط والرخططات التصاريم أعرال جاءت الخارس الترتيب وفي ،(3.60) برتوسط الريكانيكية الردنية األعرال جاءت السابع الترتيب وفي ،(3.56) برتوسط التأثيث أعرال جاءت السادس الترتيب وفي (.3.66) برتوسط التحتية البنية أعرال جاءت واألخير الثارن الترتيب وفي ،(.3.4) برتوسط 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 التشييد رنظورة رن روقعهم حسب العينة أفراد توزيع بين عالقة وجود عدم حصائيةاإل االختبارات أظهرت وقد اتوافق ثرة أن يعني را وهو التغيير، ألوارر عرضة األكثر الرجال هي الرعرارية األعرال لكون ؛تقديراتهم وبين التقدير. هذا تجاه العينة أفراد راءآ بين اداخلي ثالثال على البحث ركز فقد ،الرشاريع على تأثيراتها التغيير أوارر ترارس خاللها رن التي القنوات عن أرا -6 الزرن بعارل يتعلق وفيرا الجودة. وعارل التكلفة وعارل الزرن عارل وهي: الرشاريع إدارة في ساسيةاأل قنوات التغيير أوارر أن على بشدة وافقت البحث عينة إجرالي رن %23.3 أن الريدانية الدراسة نتائج كشفت فقد نسبة وبلغت ،%62.2 فقط بالروافقة أشاروا الذين نسبة بلغت حين في الرشروع، في تأخير عليها يترتب بشدة بالرفض أشاروا الذين نسبة بلغت وأخيرا ،%1.2 نسبتهم فبلغت بالرفض شارواأ الذين أرا ،%6 الرحايدين 1.2.% تأخير في تتسبب التغيير أوارر أن على تؤكد البحث عينة أفراد رن الغالبة النسبة بأن القول يركن هنا ورن را فإذا ،الكلية البحث عينة حجم نصف الرأي هذا على بشدة بالروافقة أشاروا الذين نسبة تعدت حيث ،الرشروع الرأي. هذا على تؤكد العينة رن الغالبية أن لوجدنا %62.2 فقط بالروافقة شارواأ الذين نسبة إليهم أضفنا النتائج كشفت فقد ،الرشروع زرن في تأثير عنها ينجم التغيير أوارر أن على أكدت التي النتيجة تلك رع واتساقا وقت إلى يحتاج التغيير أوارر ازنجإ أن إلى أشارت العينة حجم إجرالي رن %33.2 أن عن أيضا الريدانية 15..6 أن حين في ،للرشروع األصلي الوقت رن الرائة في عشرين رن أقل إلى عشرة رن رقداره ضافيإ إلى يحتاج أنه إلى %60.3 أشار كرا ،بالرائة عشرة رن أقل إلى خرسة بين را وقت إلى يحتاج نهأ إلى أشاروا وتساوت ،%5 عن يقل لوقت يحتاج أنه إلى %6 أشار بينرا هذا ،بالرائة ثالثين رن وأقل عشرين بين را وقت يحتاج أنه إلى أشاروا والذين رائةال في ربعينأ رن وأقل ثالثين بين را لوقت تاجيح أنه إلى أشاروا الذين نسبة حدة. على رنهم لكل %5.5 بواقع %40 عن يزيد لوقت بشدة توافق العينة حجم إجرالي %رن53.5 أن عن الريدانية الدراسة نتائج كشفت فقد التكلفة بعارل يتعلق وفيرا نسبة وبلغت ،%33.2 بالروافقة أشار حين في ،الرشروع تكلفة زيادة في تتسبب التغيير أوارر أن على ذلك ويعني بشدة. أرفض اختيار لىإ العينة أفراد رن أي يشر لم بينرا ،%3.1 والرافضين ،%5.4 الرحايدين الرشروع. تكلفة بزيادة التغيير أوارر فيه تتسبب الذي الدور على العينة أفراد بين كبير جراعإ ثرة نأ التغيير أوارر أن على أكدت ( %42.5 )برقدار الدراسة عينة فرادأ رن الغالبة النسبة أن عن النتائج كشفت كرا أن حين في ،للرشروع األصلية القيرة رن %(10 رن وأقل 5 رن أكثر ) قيرته برا التكلفة زيادة في تتسبب %16.5 أشار بينرا هذا ، %(60 رن وأقل %10 رن )أكثر بين را تتراوح الزيادة هذه أن إلى أشاروا 36% ثالثة يتعدى برا النسبة هذه إجرالي ويرثل ،%(30 رن وأقل %60 رن )أكثر بين را تتراوح الزيادة هذه أن إلى النظام حدده را عن تزيد بنسبة فعلية تكلفة عنها ينجم التغيير أوارر أن لىع يؤكد را وهو ،العينة حجم أرباع الى أشاروا %(53.1) البحث عينة فرادأ رعظم نأ نجد بينرا (.1466)رجلس الوزراء، قصىأ كحد %(10) رن البد االضافية الربالغ والعتراد .الحكورية الرشتريات نظام حددها التي النسبة تتجاوز التغيير أوارر قيرة نأ 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 لرروره جدا طويل جراءاإل هذا ورسار ،ب(.146)وزارة الرالية، الرسرية الروافقة ألخذ الوزراء لرجلس الرفع رن العام القطاع رشاريع رنه تعاني لرا تفسير هذا وفي التغيير ررأ اعتراد تأخير في يتسبب ررا الرالية بوزارة إنجازها. في وتأخير تعثر أشارت البحث عينة حجم إجرالي رن %26.6 أن عن الريدانية النتائج كشفت الجودة بعارل يتعلق وفيرا أشاروا الذين نسبة بلغت حين في ،الرشاريع جودة على اتأثير ترارس التغيير أوارر أن على بشدة بالروافقة رفضوا الذين نسبة بلغت بينرا %،6.3 الرافضين ونسبة ،%..6 الرحايدين نسبة وبلغت %،61.1 بالروافقة عينة أفراد رن العظرى الغالبية بأن القول يركن هنا ورن العينة. حجم إجرالي رن فقط %1.2 الرأي هذا وبشدة الرشاريع. جودة على التأثير شأنها رن التغيير أوارر بأن القائل الرأي على توافق البحث أوارر بتأثير القول لهم سبق ررن %2..2أن عن الريدانية النتائج كشفت ،التغيرات تلك بطبيعة يتعلق وفيرا هذا أن إلى أشاروا %31.4 أن حين في ،إيجابي التأثير هذا أن على يؤكدون ،الرشاريع ةجود على التغيير الرالك فئة في اإليجابي التأثير إلى أشاروا الذين نسبة تركز أيضا النتائج وأوضحت ،سلبي هو التأثير الرستفيدة. الجهة فئة في السلبي التأثير إلى أشارت التي النسبة تركزت ذلك رقابل في ،والرقاولين :والتوصيات الخاتمة أحد بوصفها ،التغيير أوارر برسألة تتعلق التي ،والروضوعات التساؤالت رن اعدد الدراسة هذه في الباحث طرح التي والتساؤالت القضاياجريع إلى تطرق أنه هنا يزعم ال والباحث ،التشييد رشاريع إدارة في الرهرة الجوانب وهو ،األهرية رنتهى في لروضوع وصفية فيةكش رحاولة يعد الباحث أنجزه فرا ،التغيير أوارر روضوع يطرحها وجه على السعودي بالواقع الرعنية والدراسات عرورا العربية الدراسات فيه ندرت اليه، اإلشارة سبق كرا روضوع الخصوص. رجال وهو ،الركتبية الحكورية للرباني التشييد رشروعات إدارة في التغيير أوارر برسألة رعني الباحث نوأل قضايا حول البحوث رن رزيد إجراء إلى يحتاج األرر فإن ،سنة عشرين على تزيد جيدة ريدانية خبرة فيه يرتلك تلك رن الباحث إليها خلص الرهرة الرالحظات رن عدد وهناك الحالية. دراسته في الباحث اله يتطرق لم أخرى اآلتي: النحو على يركن إيجازها الدراسة ويطرح ،التشييد رشاريع بإدارة يتصل قيداوتع تشابكا أكثر روضوع رن جزء التغيير أوارر روضوع أن -أوال تلك نإ :القول ويركن ،والدراسات البحوث رن رزيد خالل رن إجابة إلى تحتاج التي التساؤالت رن الكثير تداخل الرثال سبيل على رنها الحكورية، الرشاريع تنفيذ عرقلة في تتسببو ،رتشابكةو ،رعقدة التساؤالت ظاهرة وتناري ،الرشروع وثائق جودة ونقص الصالحيات، تفويض وعدم ،التنفيذية األجهزة بين االختصاصات .التغييرية األوارر (، 1466)رجلس الوزراء، فقط %10 تتجاوز ال بنسبة العقد زيادة أجاز والرشتريات الرنافسات نظام أن -ثانيا التغيير أوارر قيرة نأ إلى أشاروا %(53.1) العينة نصف رن أكثر نأ نجد حين في ،أ(.146)وزارة الرالية، لرنافساتا نظام ضرن للتغيير الرنظرة الرواد في النظر إعادة يستوجب ررا النظام؛ حددها التي النسبة جاوزتت 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 نحو التوجه األرر ستوجبي الحالي الوضع رعالجة أخرى ناحية ورن ،ناحية رن هذا ،الحكورية والرشتريات . الظروف ضيقأ في اال %10 عن التغيير أوارر قيرة زيادة عدمب إدارية ثقافة عليه نطلق أن يركن را تشكيل بـ: الباحث يوصي وأخيرا االحتياجات على للتعرف ؛الرستفيدة الجهات أو الرباني لرستخدري استقصاء بعرل يقوم أن الرالك على .1 ئهوفا رن للتأكد الرساحي البرنارج وتدقيق رراجعة على العرل اخر وبرعنى التصريم. عرلية قبل الرطلوبة الرستخدم. برتطلبات ،للرحاكاة الرتخصصة الحاسوبية البرارج باستخدام األبعاد ثالثي نروذجأ بإنتاج مرصرال الستشاريا إلزام .6 ستوعبي كي ؛الداخلية والحركة التأثيث رع الداخلي والتوزيع ةالخارجي الرباني شكل توضيح رنه الهدف لرختلف رحاكاة عرل على اقادر البرنارج هذا يكون أن على وتفاصيله، هعناصر الرستفيدون رن الرشروع في أو ،الربنى رن جزء في رعرارية تعديالت ءجراإ حالة في ريمللتص بدائل وطرح الربنى حداتو و وظائف .هكل الربنى رنافسة.لل الرشروع طرح قبل تعارضها؛ عدم رن والتأكد ،الرشروع عقد وثائق جودة ضبط على العرل .3 المراجع: (. تقييم دور وكفاءة الركاتب االستشارية في إدارة عرلية تنفيذ رشاريع 6014إسراعيل، عصام رحرد حسين ) الررلكة العربية السعودية. –األحساء –. حالة دراسية إنشاء جارعة الرلك فيصل pmoالتشييد الهندسية دراسة رقدرة الستكرال رتطلبات الحصول على درجة الدكتوراه في قسم إدارة الرشاريع بكلية اإلدارة واالقتصاد في األكاديرية العربية بالدنرارك. البحوث الوصفية. ركتبة دار الشرق، القاهرة.(. استخدام االحصاء في 6003سلطان، عادل رحرد ) (. الرطالبات في الرشاريع بسبب أخطاء التصريم وأوارر التغيير. رجلة البناء، 6002شعبان، رحرد حسن ) العدد التاسع، الررلكة العربية السعودية. ة.(، نظام الرنافسات والرشتريات الحكوري1466رجلس الوزراء، الررلكة العربية السعودية ) أ(، نروذج عقد اشغال عارة ورلحق التعديالت..146وزارة الرالية، الررلكة العربية السعودية ) ب(، الالئحة التنفيذية لنظام الرنافسات والرشتريات الحكورية..146وزارة الرالية، الررلكة العربية السعودية ) al-dubaisi, a. h. 2000. change orders in construction projects in saudi arabia. proquest, umi dissertations publishing). alnuaimi, a. s., taha, r. a., mohsin, m. a., and harthi, a. a. s. 2010. causes, effects, benefits, and remedies of change orders on public construction projects 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 in oman. journal of construction engineering and management, 136(5), 615622. assaf, s. a., and al-hejji, s. 2006. causes of delay in large construction projects. international journal of project management, 24(4), 349-357. günhan, s., arditi, d. and doyle, j. 2007, "avoiding change orders in public school construction", journal of professional issues in engineering education and practice, 133(1):67-73. ibn-homaid, n. t, eldosouky, a. i. and al-ghamdi, m. a. 2011. change orders in saudi linear construction projects. emirates journal for engineering research, 16(1): 33-42. moselhi, o., assem, i., and el-rayes, k. 2005. change orders impact on labor productivity. journal of construction engineering and management, 131(3): 354-359. ndihokubwayo, r., 2008, an analysis of the impact of variation orders on project performance, cput theses and dissertations. taylor timothy r. b.; moin uddin; paul m. goodrum، ph.d.، p.e.; alex mccoy; and yongwei shan, 2012. change orders and lessons learned: knowledge from statistical analyses of engineering change orders on kentucky highway projects. journal of construction engineering and management, 138(12): 1360-1369. ( يوضح خصائص عينة البحث1جدول رقم ) الجهة سنوات الخبرة النسبة للعينة سنوات 10أقل رن الكلية سنوات 10أكثر رن 20وأقل رن سنة 20أكثر رن 30واقل رن سنة 30أكثر رن 34 6 6 6 16 رالك 47.1% 17.6% 17.6% 17.6% 13.3 104 20 22 38 24 رقاول 23.1% 36.5% 21.2% 19.2% 40.6 56 10 10 12 24 استشاري إشراف 42.9% 21.4% 17.9% 17.9% 21.9 10 0 2 4 4 استشاري التصريم 40.0% 40.0% 20.0% .0% 3.9 44 14 10 18 2 الرشاريعاستشاري إدارة 4.5% 40.9% 22.7% 31.8% 17.2 8 0 0 6 2 الجهة الرستفيدة 25.0% 75.0% .0% .0% 3.1 256 50 50 84 72 الرجروع 28.1% 32.8% 19.5% 19.5% 100.0% 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 45 وارر التغييرأطراف الفاعلة في فراد العينة حسب تقديراتهم لألأ( يوضح توزيع 6جدول رقم ) االختيارات األطراف ال يحدث مطلقاً ال يحدث يحدث أحياناً يحدث غالباً يحدث بكثرة الوسط الحسابي االنحراف الترتيب المعياري المالك 80 66 92 10 8 ك 3.78 1.032 1 % 2.8 3.5 32.5 23.3 28.3 المقاول 38 68 124 12 14 ك 3.41 0.981 2 % 4.9 4.2 43.8 24 13.4 استشاري اإلشراف 10 30 162 38 16 ك 2.98 0.818 4 % 5.7 13.4 57.2 10.6 3.5 استشاري إدارة المشاريع 10 42 144 40 20 ك 2.89 0.887 5 % 7.1 14.1 50.9 14.8 3.5 الجهة المستفيدة 40 72 102 26 16 ك 3.37 1.062 3 % 5.7 9.2 36 25.4 14.1 يوضح طرق احتساب قيرة أوارر التغيير( 3جدول رقم ) االختيارات الطرق ال يحدث مطلقاً ال يحدث يحدث أحياناً يحدث غالباً يحدث بكثرة الوسط الحسابي االنحراف الترتيب المعياري سعر البند حسب العقد األصلي 88 82 60 12 14 ك 3.85 1.114 1 % 5.5 4.7 23.4 32 34.4 إلى سعر البندالتفاوض منسوبا 18 92 100 30 16 ك 3.26 0.972 3 % 6.2 11.7 39.1 35.9 7 التكلفة الحقيقية مضافة إليها الربح 34 66 112 30 14 ك 3.30 1.020 2 % 5.5 11.7 43.8 25.8 13.3 سعر تم تحديده بعد التفاوض 42 58 90 40 26 ك 3.20 1.189 4 % 10.2 15.6 35.2 22.7 16.4 ( يوضح عالقة طرق احتساب قيرة أوارر التغيير وروقع الطرف رن رنظورة التشييد4جدول رقم ) المتغير )السؤال( الجهة المستفيدة استشاري اإلدارة استشاري التصميم استشاري اإلشراف مقاول مالك وسط حسابي انحراف رعياري وسط حسابي انحراف رعياري وسط حسابي انحراف رعياري وسط حسابي انحراف رعياري وسط حسابي انحراف رعياري وسط حسابي انحراف رعياري سعر البند حسب العقد 886. 4.25 1.292 3.77 0.843 3.6 1.208 3.82 1.062 3.87 1.013 3.94 األصلي التفاوض منسوبا إلى سعر 463. 3.75 0.961 2.23 0.422 3.80 0.999 3.14 980. 3.33 1.044 3.00 البند التكلفة الحقيقية مضافا 1.389 3.25 0.983 3.32 1.398 3.20 0.943 3.36 1.019 3.17 988. 3.59 إليها الربح سعر تم تحديده بعد 0.463 2.75 1.284 3.45 1.633 4.00 1.202 3.29 1.097 3.04 1.179 3.06 التفاوض شفوي( يوضح أوارر التغيير التي تنفذ بتوجيه 5جدول رقم ) االختيارات الطرق ال يحدث مطلقاً ال يحدث يحدث أحياناً يحدث غالباً يحدث بكثرة الوسط الحسابي االنحراف الترتيب المعياري التغييرات ذات القيمة المحدودة 46 62 98 26 24 ك 3.31 1.160 3 % 9.4 12.2 38.8 24.2 18 التغييرات ضمن أنشطة المسار الحرج 16 46 98 66 30 ك 2.81 1.061 2 % 11.7 25.8 38.3 18 6.2 االمتناع عن التنفيذ لحين التعميد الخطي 44 60 110 32 10 ك 3.38 1.033 1 % 3.9 12.5 43 23.4 17.2 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 45 رنظورة التشييد وتقديراتها ألوارر التغيير التي تنفذ شفويا رن( يوضح التباين بين فئات العينة رن حيث روقعها 2جدول رقم ) اختبار "شيفيه" لداللة الفروق بين المجموعات تحليل التباين المتوس المتغ ط رصدر التباين ير رجروع الرربعات درجات الحرية رتوسط الرربعا ت قيرة "ف" وداللتها الروقع في الرنظورة رالك ن = 34 رقاول ن = 104 أ. اإلشراف 52ن = أ. التصريم 10ن = أ. االدارة ن = 44 ج. رستفيدة .ن= ودة حد الم مة لقي ت ا ذا رات غيي الت بين الرجروعات 8.832 5 1.766 .255 3.12 رالك 3.37 248. رقاول داخل الرجروعات 334.168 250 1.337 أ. اإلشراف .046 .294 3.07 أ. التصريم .282 .035 0.329 3.40 255 343.000 الرجروع 3.55 145. 474. 180. 428. أ. اإلدارة ج. رستفيدة .632 .328 .487 .350 .205 3.75 رج لح ر ا سا الم ن ضم ت ييرا لتغ ا بين الرجروعات 12.633 5 .045* * 3.31 رالك 3.06 328. رقاول داخل الرجروعات 274.367 250 2.527 أ. اإلشراف .487 .159 2.73 أ. التصريم .459 .131 .029 2.57 1.097 255 287.000 الرجروع 2.60 455. 474. 315. 0.13 أ. اإلدارة ج. رستفيدة .441 .769 .929 .900 .455 3.05 فيذ لتن ن ا ع اع متن اال بين الرجروعات 7.527 5 1.505 .213 3.53 رالك 3.29 241. رقاول داخل الرجروعات 264.473 250 1.423 أ. االشراف .065 .176 3.46 أ. التصريم .471 .712 .536 4.00 255 272.000 الرجروع 3.27 0727 192. 016. 257. أ. االدارة ج. رستفيدة .529 .288 .464 1.000 .273 3.00 ** دال عند رستوى 0.05* دال عند رستوى رعنوية .0.01رعنوية أ. اإلشراف = استشاري اإلشراف، أ. التصريم = استشاري التصريم، أ. اإلدارة= استشاري اإلدارة، ج. رستفيدة = الجهة الرستفيدة الذي يجعل رن أرر التغيير أررا نافذا ( يوضح تقديرات أفراد عينة البحث حول الطرف 6دول رقم )ج % ك الجهة 43.8 112 المالك المالك والمقاول واستشاري إدارة 13.3 34 المشاريع 10.2 20 المالك واستشاري اإلشراف 4.7 12 المالك واستشاري إدارة المشاريع 3.9 10 المالك والجهة المستفيدة 3.1 8 استشاري إدارة المشاريع 2.3 6 اإلشراف استشاري 2.3 6 الجهة المستفيدة 8. 2 استشاري إدارة المشاريع مع المالك استشاري اإلشراف واستشاري إدارة 8. 2 المشاريع 8. 2 المالك والمقاول 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 45 8. 2 المالك والمقاول والجهة المستفيدة 8. 2 المقاول واستشاري اإلشراف 8. 2 المقاول والجهة المستفيدة %100 256 المجموع ( يوضح األعرال التي يحدث بها أوارر التغيير.جدول رقم ) االختيارات األعمال ال يحدث ال يحدث مطلقاً يحدث أحياناً يحدث غالباً يحدث بكثرة الوسط الحسابي االنحراف الترتيب المعياري األعمال المعمارية 74 108 72 2 ك 3.98 .802 1 % .8 28.1 42.2 28.9 أعمال التصميم الداخلي 84 80 48 12 2 ك 3.91 .941 2 % .8 4.7 30.6 31.2 32.8 األعمال الكهربائية 54 98 94 8 2 ك 3.76 .847 3 % .8 3.1 36.7 38.3 21.1 األعمال الميكانيكية 52 86 108 8 2 ك 3.70 .855 4 % .8 3.1 42.2 33.6 20.3 التصاميم والمخططات 58 82 88 24 4 ك 3.65 .983 5 % 1.6 9.4 34.4 32 22.7 أعمال التأثيث 66 70 76 32 12 ك 3.57 1.139 6 % 4.7 12.5 29.7 27.3 25.8 األعمال المدنية 22 94 128 10 2 ك 3.48 .741 7 % .8 3.9 50 36.7 8.6 أعمال البنية التحتية 22 68 130 28 8 ك 3.27 .881 8 % 3.1 10.9 50.8 26.6 8.6 ( يوضح العالقة بين الروقع رن رنظورة التشييد وتقدير أفراد العينة لكون األعرال 5جدول رقم ) الرعرارية هي الرجال األكثر عرضة ألوارر التغيير الروقع رن رنظورة التشييد التقديرات الرجروع ال يحدث رطلقا يحدث أحيانا يحدث غالبا يحدث بكثرة رالك 34 12 16 6 0 ك % .0% 17.6% 47.1% 35.3% 100.0 % رقاول 104 22 44 36 2 ك % 1.9% 34.6% 42.3% 21.2% 100.0 % استشاري اإلشراف 56 14 22 20 0 ك % .0% 35.7% 39.3% 25.0% 100.0 % استشاري التصريم 10 4 6 0 0 ك % .0% .0% 60.0% 40.0% 100.0 % استشاري إدارة الرشاريع 44 20 16 8 0 ك % .0% 18.2% 36.4% 45.5% 100.0 % الجهة الرستفيدة 8 2 4 2 0 ك % .0% 25.0% 50.0% 25.0% 100.0 % الرجروع 256 74 108 72 2 ك % .8% 28.1% 42.2% 28.9% 100.0 % 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 تأخير الرشروعات ( يوضح تقديرات أفراد العينة لدور أوارر التغيير في10جدول رقم ) الروقع رن رنظورة التشييد أوارر التغيير تتسبب في تأخير الرشروع أرفض الرجروع بشدة أوافق رحايد أرفض أوافق بشدة رالك 34 18 14 2 0 0 ك % .0% .0% 5.9% 41.2 % 52.9% 100.0 % رقاول 104 74 24 4 0 2 ك % 1.9% .0% 3.8% 23.1 % 71.2% 100.0 % استشاري اإلشراف 56 30 14 8 4 0 ك % .0% 7.1 % 14.3 % 25.0 % 53.6% 100.0 % استشاري التصريم 10 6 2 2 0 0 ك % .0% .0% 20.0 % 20.0 % 60.0% 100.0 % استشاري إدارة الرشاريع 44 32 8 2 0 2 ك % 4.5% .0% 4.5% 18.2 % 72.7% 100.0 % الجهة الرستفيدة 8 2 6 0 0 0 ك % .0% .0% .0% 75.0 % 25.0% 100.0 % الرجروع 256 162 68 18 4 4 ك % 1.6% 1.6 % 7.0% 26.6 % 63.3% 100.0 % ( يوضح الوقت اإلضافي إلنجاز أوارر التغيير نسبة للردة األصلية للرشروع11جدول رقم ) الوقت اإلضافي إلنجاز أوارر التغيير نسبة للردة األصلية الروقع رن رنظورة التشييد الرجروع 5أقل رن % أكثر رن وأقل 5% %10رن أكثر رن وأقل 10% %20رن أكثر رن وأقل 20% %30رن أكثر رن وأقل 30% %40رن أكثر رن 40% رالك 34 4 2 6 6 10 6 ك % 17.6% 29.4% 17.6% 17.6% 5.9% 11.8% 100.0 % رقاول 104 0 6 22 42 30 4 ك % 3.8% 28.8% 40.4% 21.2% 5.8% .0% 100.0 % استشاري اإلشراف 56 4 2 12 22 12 4 ك % 7.1% 21.4% 39.3% 21.4% 3.6% 7.1% 100.0 % استشاري التصريم 10 0 2 2 0 4 2 ك % 20.0% 40.0% .0% 20.0% 20.0% .0% 100.0 % 44 6 0 8 14 14 2 كاستشاري أدارة 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 43 الرشاريع % 4.5% 31.8% 31.8% 18.2% .0% 13.6% 100.0 % الجهة الرستفيدة 8 0 2 2 2 2 0 ك % .0% 25.0% 25.0% 25.0% 25.0% .0% 100.0 % الرجروع 256 14 14 52 86 72 18 ك % 7.0% 28.1% 33.6% 20.3% 5.5% 5.5% 100.0 % العينة لدور أوارر التغيير في زيادة تكلفة الرشروع( يوضح تقديرات أفراد 16جدول رقم ) الروقع رن رنظورة التشييد التكلفة الرجروع أرفض بشدة اوافق رحايد أرفض أوافق بشدة رالك 34 12 12 10 0 ك % .0% 29.4 % 35.3 % 35.3% 100.0 % رقاول 104 64 32 8 0 ك % .0% 7.7% 30.8 % 61.5% 100.0 % استشاري إشراف 56 30 22 2 2 ك % 3.6% 3.6% 39.3 % 53.6% 100.0 % استشاري تصريم 10 6 2 2 0 ك % .0% 20.0 % 20.0 % 60.0% 100.0 % استشاري إدارة رشاريع 44 24 12 2 6 ك % 13.6 % 4.5% 27.3 % 54.5% 100.0 % الجهة الرستفيدة 8 2 6 0 0 ك % .0% .0% 75.0 % 25.0% 100.0 % الرجروع 256 138 86 24 8 ك % 3.1% 9.4% 33.6 % 53.9% 100.0 % 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 ( يوضح تقديرات أفراد العينة لتكلفة أوارر التغيير نسبة للقيرة األصلية للرشروع13جدول رقم ) الروقع رن رنظورة التشييد للرشروعتكلفة أعرال التغيير نسبة إلى القيرة األصلية أقل رن الرجروع 5% %5أكثر وأقل رن 10% %10أكثر وأقل رن 20% %20أكثر وأقل رن 30% %30أكثر وأقل رن 40% أكثر رن 40% رالك 34 0 0 4 8 22 0 ك % .0% 64.7% 23.5% 11.8% .0% .0% 100.0 % رقاول 104 2 4 12 42 44 0 ك % .0% 42.3% 40.4% 11.5% 3.8% 1.9% 100.0 % استشاري إشراف 56 0 4 4 16 30 2 ك % 3.6% 53.6% 28.6% 7.1% 7.1% .0% 100.0 % استشاري التصريم 10 0 2 2 2 4 0 ك % .0% 40.0% 20.0% 20.0% 20.0% .0% 100.0 % استشاري إدارة الرشاريع 44 2 4 8 12 16 2 ك % 4.5% 36.4% 27.3% 18.2% 9.1% 4.5% 100.0 % الرستفيدةالجهة 8 0 0 2 2 4 0 ك % .0% 50.0% 25.0% 25.0% .0% .0% 100.0 % الرجروع 256 4 14 32 82 120 4 ك % 1.6% 46.9% 32.0% 12.5% 5.5% 1.6% 100.0 % 5101 1العدد 8مجلة القادسية للعلوم الهندسية المجلد 44 ( يوضح تقديرات أفراد العينة لردى تأثير أوارر التغيير على جودة الرشاريع14دول رقم )ج رن رنظورة التشييدالروقع التقديرات الرجروع أوافق بشدة اوافق رحايد أرفض أرفض بشدة رالك 34 26 4 2 2 0 ك % .0% 5.9% 5.9% 11.8% 76.5% 100.0% رقاول 104 64 32 6 0 2 ك % 1.9% .0% 5.8% 30.8% 61.5% 100.0% استشاري إشراف 56 36 6 10 2 2 ك % 3.6% 3.6% 17.9% 10.7% 64.3% 100.0% استشاري التصريم 10 8 2 0 0 0 ك % .0% .0% .0% 20.0% 80.0% 100.0% استشاري ادارة الرشاريع 44 34 8 0 2 0 ك % .0% 4.5% .0% 18.2% 77.3% 100.0% الجهة الرستفيدة 8 4 2 2 0 0 ك % .0% .0% 25.0% 25.0% 50.0% 100.0% الرجروع 256 172 54 20 6 4 ك % 1.6% 2.3% 7.8% 21.1% 67.2% 100.0% الرشروعات جودة على التغيير أوارر تتركه الذي التأثير لطبيعة العينة أفراد تقدير يوضح (15) رقم جدول الموقع من منظومة التشييد التقديرات المجموع تأثيرات سلبية تأثيرات إيجابية مالك 30 10 20 ك % 66.7 33.3 100.0% مقاول 96 26 70 ك % 72.9 27.1 100.0% استشاري إشراف 42 12 30 ك % 71.4 28.6 100.0% استشاري التصميم 10 4 6 ك % 60 40 100.0% استشاري إدارة المشاريع 42 15 27 ك % 64.3 35.7 100.0% الجهة المستفيدة 6 4 2 ك % 33.3 66.7 100.0% المجموع 226 71 155 ك % 68.6 31.4 100.0% الخلاصة 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 781 األولالكلل للطور تشقق على بداية اإلجهادتغيير نسبة تأثيردراسة د. عماد توما بني الكرش هيئة التعليم التقني / المعهد التقني الموصل emadbane2007@yahoo.com 4102تشرين الثاني 9ُقبل 4102 حزيران 8ُاستلم :المستخلص في البحث الحالي ، تمت دراسة تأثير تغيير نسب اإلجهاد في بداية تشقق الكلل لسبيكة األلمنيوم المصنوع منها وذلك بأخذ نموذج من ريشةة لطةائرم مةن ةذا النةوع وتقطي هةا mi 25ريش الطائرات المروحية الروسية نوع مطلوبة لالختبار وباسةتددام م امةل ةةدم اإلجهةاد متغيةراس رئيسةاس وذلةك مةن خةال مةل ةةق إلى نماذج باألب اد ال نسةةةةةةب إجهةةةةةةاد مدتل ةةةةةةة و ةةةةةةي أولةةةةةةي فةةةةةةي النمةةةةةةاذج المدتبةةةةةةرم مو ةةةةةةد تمةةةةةةت ا ختبةةةةةةارات نةةةةةةد خمةةةةةة (r = -1 , 0 , 0.1 , 0.3 , 0.5وتم ند ا إجراء ا ختبار )ات المدتل ة لدراسة تأثير تغيير ا في بداية مسةتهل الكلل ومقارنة النتائج ال ملية التي تم الحصو ليها مع القيم المحسةوبة مةن غةيل الناريةات وال ر ةيات تشقق الموجودم في ذا المجا مف ند كل نسبة إجهاد تم اخذ نماذج مدتل ة ، وذلك للحصو لى يمة مدى م امل ةةدم م ند ا اإلجهاد اإلجهةاد الموجبةة بازديةاد نسةبةمن النتائج التي تم الحصو ليهةا يتبةين أق يمةة مةدى م امةل ةةدم اإلجهةاد تقةل الكللمتشقق مستهللوتزداد بازدياد نسبة اإلجهاد السالبة keywords: aluminum alloy, threshold of the fatigue, negative stress ratio, cracks. the effect of stress ratio on fatigue threshold of crak in mode (i) abstract in the present study, the effect of the stress ratio change on the threshold of the fatigue cracks for an aluminum alloy have been researched. this aluminum alloy was taken from a blade of russian mi25 helicopter. a specimen of mi25 blade has been cut into testing specimens of standard dimensions; the stress intensity factor as a basic variable has been calculate and used by making an initial crack in the test specimens. the test have been conducted for five different stress ratio : ( r = 1 , 0.0 , 0.1 , 0.3 , 0.5 ) : several tested have been done to study the effect of these change on the threshold of fatigue crack , the mailto:emadbane2007@yahoo.com mailto:emadbane2007@yahoo.com 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 788 result obtained in this research were compared to some well knows previous scientific theories and research in this field . at each stress ratio ( r ) , several specimens have been used to obtain the threshold stress intensity factor for that value of ( r ) . from the results obtained , it is clear that the value of the threshold stress intensity factor range (δk) decreases as the stress ratio increases. whereas ; at a negative stress ratio: (δk) increase for threshold fatigue crack . المقدمة : إن الكلفةةةل الجة عةةةل فةةةن المفةجةةةةل الكفةعوةةةل لل لاككةةةك ةااعةةةلاة الكككةجكككةةةل الكم لفةةةل كةةةن الجة كةةةل ا ج ةةةة كل لذلك فةن ال لاسةل فن المفةة الكللةي جة امةذ كةلا ةاسةعة ةالبشلكل ج كةن عسككل ع ا في بعض اا كةن . كن الب ةث ةال لاسةل في الككة كن العلككل ةال جةفكل.ةان جشةة ة ق م شققةل الكلل في أعج ل ةلكش الطةولال الكم لفل كؤ ي إلى أمفةجةل جة لل . فلةى شةكل اجةل جةةل فلةى ةعة ( ظ ةلthreshold fatigueإن ب اكةل كسة ل الكلةل أة ب اكةل شةق الكلةل الجكةةةذو ةبعةة كةةلةل ف ةةل كةةن فكةةل الكلةةل ةةبإ اةب ةةل ة كككةةن إلال ةةة ةبلكةةة فةة ةلال اا كةةةل فةةةن ةةذ ا جل جةل عك ةكن ام كب أ ال شق بةةل كةكن ةان ال شةققةل فةي العسةم الكع ة كككةن أن جكةة ة قة م ب ةلابط .[2,1 ] ااطةال الالال ك إابة ةل كةفكل فلى أن الع كة كةن ال لاككةك ال ج سةكل ةةي فكةبةةة كسةبقل الجشةةة ة جشةي ةذ العكةةك أاجةةة ة جة السبةكل أة ال جكع ةفلك كب أ ال ك ن بب اكل الكلل ةجكة كن ذ العكةةك فةي الكعةة ن الكسة م كل فةي ةجكع ك ةةة ث بسةةةلفل فةوقةةةل عةةة اة ةل ةةةذا السةةةبك فةةةةن . كةةةث أن قةةة م شةةةق الكلةةةل [5,4,3]أبةةة ان ةكلكبةةةةل الطةةةةولال ( δkةان جكة الش في كجطقل كةن فك ة جككل . كس ل الكلل كؤ ي ةلاة ك كة في ال ك ن بعكل لك الكلكبةل ةاطول كطلةبل ع اة لكة لذلك كن أ ككل في عككن العكل الكطلةك ل ذ ااع ل لةذلك كةةن ةذ الكجطقةل ااكاةل . [7 , 6]ى أفكةل الكلل ال ي م الطةولال ككة ل عككن ك ة جةةةك الع كةة كةةن الب ةةةث ال ةةي ام ةةل فةةي عكةةكن ب اكةةل جكةةة شةةق الكلةةل لسةةبةوك االكجكةةةم الكسةة م كل فةةي جكع كلكبةل الطةةولال جسةم كةن ةذ الب ةةث ةم إعلاؤ ةة ةل ةل فةةل ة بةكن كةن ةذ الب ةةث إن ب اكةل ةشةةل كةةع ال ةةل ةالقسةةم المةةل كةةن الب ةةةث ةةم إعلاؤ ةةة ةةل ةةل ال ةاطوةةل ةفجةة الكلةةل ة ق كةة ذال فلجةةل كب لعةةةةل لالكةةةل كم لفةةةل ةجسةةةك إع ةةةة كم لفةةةل أكاةةةة لل ةةةةل فلةةةى بكةجةةةةل ك جةفةةةل لسةةةبةوك االكجكةةةةم ااكاةةةل لع ةة .أكة الب ث الةذي ج ةن ب ة فكع كة فلةى لاسةل ةياكل بككةل جسةك ا[8]اس م اكةة في لاككك الطةولال ( 6063t832( لسةةةةةةبككل أالكجكةةةةةةةم الكطةبقةةةةةةل لسةةةةةةبككل ألكجكةةةةةةةم جةةةةةةة r=-1,0,0.1,0.3,0.5 الكم لفةةةةةةل ةةةذ ب لاسةةةل ( فلةةةى ب اكةةةل شةةةققةل الكلةةةلmi25ةالكسةةة م كل فةةةي ةةةجكع لكةةةش الطةةةةول الكلة كةةةل كةةةن جةةةة ال شققةل بةس م ام كعةكل ش الع ة ك بكلاة لوكسكةة : ملالمواد وطرائق الع مواصفات المعدن 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 781 . ة م قطكعة إلةى العة الكطلةةك كةن الجكةةذو كلة كل في ذا الب ث م اس م ام كع ن كيمةذ كن لكشل طةول ( ةكبلغ طةةل hind-d ( ة سكك ة البلبكل mi25ةج م امذ الكع ن كن كقطع للكشل طةول فكة كل جة ( لكةش. ةكككةن كل ظةل شةكل 5 لجةة كةن الطةةولال ككةةن ( ةفة الةلكش فةي ةذا ا 8.5m كل لكشةل فك ةة كةن جةة ألكجكةةمكطةبقل قلكبة لسةبككل ألكجكةم(. ةالكع ن ة فبةل فن سبككل 1كقطع في اللكشل كن الشكل 6063t832 كةةن كةةث ال لككةةك الككككةةةوي ةال ةةفةل الكككةجكككةةل. ة ةةم لكةةل السةةبككل فةةي اوةةل ال قكةةك ) أكة ال فةل الكككةجكككل للسةبككل (1الجةفكل ةكككن كل ظل ال لككك الكككةوي للسبككل كن الع ةل ةالسكطل جةة ألكجكةةم. ةكةجةل ةذ السةبككل فةي طةةب كقبةةل كةع سةبككل [4] فقة ةم ال ةةل فلك ةة كةن ك ة ل كع كة 6063t832 2( ةككة كبكن في الع ةل. ) ذجالشكل الهندسي للنمو ا م بةل الك ةفل ةكككن كل ظل أبعةة الجكةةذو كةن لوم كةككجل م قسكم الجكةذو الكس ل فلك إلى جكةذو ال فلكل الك طةل بإبعة ةجكةسةل كةككجلبةس م ام ( كلم ,150*20 * 5 ( ةكةجل أبعة الجكةذو a .2الشكل ( كلةةم ةككةةة كبةةكن فةةي 0.5( ةفكةة 0.2بسةةكك ( فلةةى فةةلض الجكةةةذوslit جكقةة عةة اة. ةجةة ةةم فكةةل مةة ش (. wire cutting machineالشلال الك لبةوكل ال ي س م م السلك فةي القطةع كةككجل( بةس م ام b .2الشكل ة ةةم إ ةة اث ةةذ ال م شةةةل لل ةةةل فلةةى شةة إع ةةة كجةسةةبل فةةي كجطقةةل أج ةةى اج جةةةة لل ةةةل فلةةى ةلةةل بةكن أن ال شةققةل بة أ كةن العكةةك ال ج سةكل ال ةي جشةي فةي الكعة ن أاجةةة السةبةكل كشةب ل لل قكقل ال قكقةل ال ةي ةال جكع(. اختبار الكلل ماكينة .reversed bending machine )[6]ال ةجكل العكسكل كةككجلاس م كل في ا م بةل قياس الشققة يطر سةل العكجكةل( ة ةم كةن ملل ةة كلاجبةل جشةةة ةج اس م م في ذا الب ث كع ل اةوي ك جقل ذة ف سل كلجكل الع الش ة م ام كةل ذ الطلكقل ل ةفل ااع ل المة ل ب ة ةان ذ الطلكقل غكل كجةسبل في ةلل الجكةذو الكة ةل ةكذلك س م م ذ الطلكقل لل شققةل الكةعة فلى السطإ فقط ة عطي أكةل كعلةكةةل ةةل كةة ك ة ث امةل . % ن جسبل ال كبكل كةجل فةلكل ع ا ةل ذا كةجل جسبل المطي جلكلل1المطي ةكةجل جسبل الجكةذو اإلجهادمعايرة معامل شدة ( h )كعةكل كعةكل ش الع ة اس م م فةي ةذا الب ةث جكةةذو اج جةةة فلةى شةكل ك ةةالي كسة طكلل بعةلض كلةم. ةكككةن (0.5)م ةفكقة كلة (0.2)فلى فلض الجكةذو ةكةن سكك الشة (a)ةش أةلى بعك (b)ةسكك كل ظ كن الشكل أ جة . 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 ةكآ ي (tada),(grass),(paris)ة م كعةكل كعةكل ش الع ة بةس م ام الكعة لل الكعطة كن جبل :( 3 شكل  b/afak i  ( 1) [29] فكككن سةب ة كن الكعة لل ال كل: f(a/b)أكة جككل 432 )b/a(0.14)b/a(08.13-)b/a(33.7)b/a(40.1122.1)b/a(f  (gross 1965) (bueckher 1960)ةكعةةكل الكعة لةل أفةل كةجةل كعطةة كةن جبةل العلكةةة (emery,1969) (benther ,1972) فج كة جككل % 0.2 ةال جل )a/b أن( أي 0.6اجل كن أة( سةةي a/b  0.6.) الجانب العملي ةأعلكةل ا م بةةلال فجة ةل (c˚25) كل عككع ا م بةلال في عة الكم بل ةفج لعةل لال البلفةل ج ةة (5 hz). إن الطلكقةةل الكسةة م كل فةةةي لاسةةل ب اكةةةل الكلةةل(threshold) فلةةى الجكةةةةذو قلكةةل ال كةةةلبكةجةةةل كعكجةةةة ة ةة م كلاجبةةل شةةق الجكةةةذو ةفةةي ةلةةل شةةق كةةث كةة م ككةةل الجكةةةذو كةةلة الكسةة م كل فةةي ا م بةةةل الجكةةةذو كةة م سةةعكل فةة الةة ةلال ال ةةي فجةة ة بةة أ الجكةةةذو بةل شةةق ةفجةة ةة ةث ال شةةق كةة م بةة كل الجكةةةذو كةن ال كةل الكسةلط (%20)بجكةذو آمل كع قلكل ال كل الكسلط ةك م قلكل ال كل في كل كل بكقة ال اجةل كةن ة س كل العكلكل إلى إن ج ل إلى ةلةل فة م (87.5x)اجبل فن طلك كع ل ك جقل ذي جة كبكل. ة كةن الكل ةل ة كةةل ا م بةةةلال فجةة جسةةك إع ةةة كم لفةةل ةكةجةةل ةةذ 107ب اكةةل شةةق فةةي الجكةةةذو بةةةللغم كةةن كةةلةل . (r= -1 , 0 , 0.1 , 0.3 , 0.5 ) الجسك : ةالنتائج والمناقش ( فلى بع slitاس م كل في عككع ام بةلال الطةل ااةل جكةذو اج جةة فلى شكل كس طكل ةفك ش فلاي 40mmكن إ ى ج ةك ي الجكةذو ةا مذ في ذ ا م بةلال مكسل أجةا كم لفل لجسك الع ة ة ي ) r= -1,0,0.1,0.3,0.5 ةذلك لكعة جكم ب اكل كس ل الكلل )kthكل جسبل إع ة كن ذ الجسك ( فج ال ةجكل العكسكل كةككجلكلل كن جة كسكى كةككجل ةاس م كل في ا م بةلال reversed bending machine أكة طلكقل الكلاجبل الكس م كل فكةجل الطلكقل الكبةشل إذ اس م م ) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 717 ( ةذلك ك شةف أي شق ك ث بةلجكةذو 4x 12.5*7x*12.5كع ل اةوي ك جقل بقة كبكل كبكجةن ج ةوج ( 5 , 4 ) كنةالشكل( 3( ل سةك جككل كعةكل ش الع ة . ةالع ةل 1ةاس م كل الكعة لل . لك ا م بةلال لب اكةل ةك بكن كن ام بةلال جكم ب اكل كس ل الكلل فج جسك إع ة كم لفل بةن جككل ك ى كعةكل شة إ ع ةة ( فةةةن جككةةل كةة ى r= -1( قةةل بةل كةةة جسةةبل الع ةةة الكةعبةةل بكجكةةة فجةة جسةةبل إع ةةة kthكسةة ل الكلةةل ( ج ال ا ل ةفلك كككن القةةل أن اللكةة السةةلبل لجسةك الع ةة kthكعةكل ش الع ة لب اكل كس ل الكلل أن إلةةى( .ةالسةةبك فةةي ذلةةك كلعةةع kthسةة ل الكلةةل لكةةة جككةةل كةة ى كعةكةةل شةة الع ةةة لب اكةةل ك إلةةى ةةؤ ي غلةة ال شةةق ةةياكل( ةكةةذلك جق ةةةن σmلكةةة جةةكم كعةة ل الع ةةة إلةةىاللكةةة الكةعبةةل فةةي جسةةك الع ةةة ةةؤ ي جق ةةن جككةل كةة ى كعةكةل شةة إلةةى( ة ةةذ ااسةبةك ةؤ ي .kmaxفاةلة فةن لكةةة جككةل شة الع ةةة العظكةى ( . أكةةة اللكةة السةةلبل فةةي جسةك الع ةةة فقة ةؤ ي إلةةى جق ةةن جةةكم thresholdالكلةل الع ةة لب اكةل كسةة ل ( كةةةن ةةفل ةكةةذلك لكةةة r=-1( كةةث أن جككةةل كعةة ل الع ةةة فجةة جسةةبل الع ةةة σmكعةة ل الع ةةة ك ةؤ ي إلةى ( ةكةن اةم فةةن ةذ ااسةبة.kmax ياكل غل ال شق فالة فن جق ةن جككل ش الع ة العظكى ( فج جسك الع ة السةلبل.thresholdلكة جككل ك ى كعةكل ش الع ة لب اكل كس ل الكلل ل :لمقارنة قيم مستهل الكلل مع نظريات التكهن بمستهل الك ك كقةلجل الج ةوج ال ةي ةم ال ةةل فلك ةة كةع الجظلكةةل ةالعلجةةل الكةعةة للة ك ن بب اكةل كسة ل الكلةل لجسة م ( فلةةى ب اكةةل كسةة ل الكلةةل rالع ةةة الكم لفةةل .ةا ةةم ةةذ الجظلكةةةل المة ةةل بةةةل ك ن ب ةةياكل جسةةبل الع ةةة للطةل ااةل ةالكقةلجل كع ة ي كةل ي : ( schmidt & paris )المقارنة مع نظرية التكهن للباحثين -0 ( rع ةة ةا ةة للقةةكم العةلكةل لجسةةك الع ةةة جسةبل الع ةةة ةجككةةل كسة ل الكلةةل لكعكةةةف كن كةن القةةكم لجسةةك ال ةااملى للقكم الةاطول .  r1kk oth  (2) ( ةي جككةل كة ى كعةكةل شة الع ةة فجة كة كفة إ kcl( كةث ان kmin  kclلجسةك إع ةة ةاطوةل كعةك ان الش ملل علة كل ال ةل . أكة لجسك الع ة العةلكل ف بإ العلجل كةل ي : ttanconskk oith  4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 ( ةة كة ى شة الع ةة الكةؤال لب اكةل كسة ل الكلةل ko( ةان kmin  kclلجسةك إع ةة فةلكةل كةث ان : علجل ال كلةال ي قة جة إلى ال  r1kk maxo  (3) ( كبكن ج ةوج الكقةلجل بكن جكم ب اكل كس ل الكلل ةال ي م ال ةل فلك ة كن ا م بةلال ةكعة ل ي 6ةالشكل ( ةك بكن 2 3كل ةالةاطول ةالك كالل بةلكعة ل كن ( لقكم جسك الع ة العةلschmidt & parisال ك ن للبة اكن ( 2( كطةبقل قلكبةة لكة ك ةجع كن الكعة لل r= 0.1( بةن جككل كس ل الكلل فج جسبل إع ة 6كن الشكل ( القككل ال ي م ال ةل فلك ة أفلى كن القككل r=0.3بكجكة جككل ب اكل كس ل الكلل فج جسبل إع ة ( r=0.5لكل ال ك ن بكجكة جككل ب اكل كس ل الكلل ال ي م ال ةل فلك ة فج جسبل إع ة الك ةجعل في جظ ان القكم جة ( . ةلكن ب ةل فةكل جل ظ كن الشكل أ3 ي اكال قةلبةة للقككل الك ةجعل كن كعة لل ال ك ن طةب كقبةل كقةلجل بةلقكم ( ي فيthresholdال ي م ال ةل فلك ة كن ا م بةلال لب اكل كس ل الكلل ( .schmidt & parisالكس ملعل كن كعة ل ي ال ك ن للبة اكن ( klensil & lukas )المقارنة مع نظرية التكهن للباحثين -4 ( فةةي جككةل ب اكةةل كسةة ل الكلةةل rالجظلكةل الاةجكةةل ال ةةي ةةم جشةةة كسةة ل الكلةةل ة ةةف ةياكل جسةةبل الع ةةة kthة البة اةةن ( اج ل ةklensil & lukas ةال ةي سة عكل بجطةة ةاسةع فةي لكةل بكةجةةل ب اكةل كسة ل ) الكلل ةال ي عطى كةل ي :   r1kk thoth (4) : أن كث  البةة اكن ( ةي اةبةل الكعة ن ةكة م عككج ةة كم بلكةةة ةجكك ةة كقة ل كةن جبةلparis & erdogan ) ( للقكم الكةعبل لجسك الع ة ةلكةن =0.6( ل كةن lindly )1691( ةكذلك كق ل كن جبل البة ث 1693 ج ةوج ا م بةلال العكلكل لب اكل كس ل الكلل أن( جل ظ 7( .ةكن الشكل 0-1جكك ة ب ةل فةكل لاةح بكن ( klensil & lukas( ةةي اجةةل كةةن القةةكم الك ةجعةةل كةةن جبةةل جظلكةةل r=0.1,0.3,0.5فجةة جسةةك الع ةةة ( .4ةلكج ة في طةب كقبةل كع مط اج كةل ال ك ن للكعة لل 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 ( mecevily & gregor )المقارنة مع نظرية التكن للباحثين -3 ( فقة ةاةع ة rع ةة ( ةجسةبل الkthأكة الجظلكل الاةلال ال ي ف العلجل بكن ك ى كعةكةل شة الع ةة ( ة عطى العلجل كةل ي:mcevily & gregorالبة اةن tho 2 1 th k r1 r1 k          (5) ( ةةي أفلةةى كةةن لةةك ال ةةي كةة م r= 0.3,0.5جككةةل كسةة ل الكلةةل لجسةةك الع ةةة أن( جل ةةظ 8ةكةةن الشةةكل ( ةلكج ة ب ةل فةكل في طةب كقبةل .5 ال ك ن ب ة كن الكعة لل ( kaisand & mowbray )المقارنة مع نظرية التكهن للباحثين -2 ( كق ل ةل كةن جبةل kth( ةجككةل ب اكةل كسة ل الكةل rالجظلكل اللابعل ال ي ف العلجل بكن جسبل الع ة ( للقةكم الكةعبةل 5علجةل السةةبقل الكعة لةل ( ة ةذ الجظلكةل سة م م جفة الkaisand & mowbrayالبةة اكن ( بكجكة للقكم السةلبل س م م العلجل ال ةلكل :rلجسبل الع ة oth k 3/r1 r1 k     (6) جسةةةةةةك الع ةةةةةةة ( فجةةةةةةkth( كبةةةةةةكن كقةلجةةةةةةل بةةةةةةكن ج ةةةةةةةوج ا م بةةةةةةةل لقةةةةةةكم ب اكةةةةةةل كسةةةةةة ل الكلةةةةةةل 9ةالشةةةةةةكل r= -1,0,0.1,0.3,0.5 ةك بةكن كةن الشةكل أفةل فجة جسةبل 5 6( ةكبةكن القةكم الك سةةبل كةن العلج ةكن ) ( بكجكةة بةةجي القةكم 6( بةن القككل الكس ملعل كن ا م بةل ي اجل كن القككل الك ةجعل للكعة لل r= -1إع ة أفلى أة كسةةكل لقةكم الة ك ن ةلكةن عككةع القةكم ب ةةل فةكةل فةي ةافة كقبةةل كةع ال ي كال القكم الكةعبل ف ي . (kaisand & mowbrayجظلكل ال ك ن للبة اكن : االستنتاجات ( قةل بةل كةة جسةبل الع ةة الكةعبةل δkthجككل ك ى كعةكل ش الع ة لب اكةل كسة ل الكلةل قل -1 r ش الع ةة لب اكةل كسة ل الكلةل للقةكم السةةلبل لجسةبل الع ةة ( . بكجكة جككل كعةكل r = -1 ) ( ةةل ا جككةةل كةة ى كعةكةةل شةة r جةة لا ل ةفلكةة كككةةن القةةةل أن اللكةةة السةةةلبل لجسةةك الع ةةة ( . δkthالع ة لكس ل الكلل 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 لع ةةةة الكم لفةةةل( لةةة ى جسةةةك ا δkthكةةةن جةةةكم كةةة ى كعةكةةةل شةةة الع ةةةة لب اكةةةل كسةةة ل الكلةةةل -1 r = -1 , 0 , 0.1 , 0.3 , 0.5 م اس ج ةو فلجل لكةاكل لل ك ن بعكل السبككل فجة أي جسةبل ) إع ة . ( δkthك بةكن كةن مةلل كقةلجةل ج ةةوج ام بةةلال جةكم كة ى كعةكةل شة الع ةة لب اكةل كسة ل الكلةل -3 ل ةل كةن جبةل بةة اكن سةةبقكن فةي طبكة كقبةةل كةع مةط لجسك إع ةة كم لفةل كةع ةكغ الكعةة ل الكق ا ج كةل ل ذ ال كغ . المصادر : [1] mann,j.y.,"fatigue of materials", an introductory text , london , melbourne university press : xv , 155 p . ( 1976 ) . دكتور غباح محمد جميل ، مطابع جام ة الموغل ، ميكانيك المواد ، للمؤلف أياق جوق يراق ، ترجمة ال 2 ( م 1990 الطب ة الثانية ، الجزء الثاني ) [3] hudson , c.m. & scardina , j.t .," effect of stress ratio on fatigue crack growth in ( 7075 – t6 ) aluminum – alloy sheet " , engineering fracture mech . 1,429-466 ( 1969) . [4] davis , j.r " metals handbook " , second edition , desk edition , prepared under the direction of the asm international handbook committee , ( 1998 ) . [5] w . bulton , " engineering materials technology " , third edition , printed and bound in great britain , ( 1998 ) . [6] purushothaman . s ., " generalized theory of fatigue crack propagation ", ph . d. thesis columbia university , ( 1976 ) . [7] newman , j.c ., jv. " analysis of fatigue crack growth & closur near threshold condition for large crack behavior " , nasa / tm – 209133,april ( 1990 ) . [8] mackay , t . l ., " fatigue crack propagation rate at low of two aluminum sheet alloy 2024 t3 & 7075 – t5 , materials and reducibility dough's aircraft company . long beach , ca 90846 , usa , engineering fracture mechanics volume , 11 , pp . 753 – 761 ( 1979 ) . [9] mohammed , r.a. " the growth fatigue cracks in a turbine shaft steel under mixed i & iii , ph.d. tsu , january ( 1993 ) . [10] richard , w . hertzberg . " deformation & fracture mechanics of engineering materials " , material research center , lehigh university , fourth edition , ( 1995 ) . 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 alloy  y mpa  u mpa % elog.  u mpa hb e gpa 6063-t832 270 290 12 185 95 69 element weight % si 0.21 fe 0.32 cu 0.20 mn 0.20 mg 0.53 zn 0.026 al rem. يبين التركيب الكيميائي لسبيكة األلمنيوم المستخدمة في :(1الجدول ) االختبار. يبدين الخدواص الميكانيكيددة لسدبيكة األلمنيدوم نددو :(2الجددول 6063-t832.والمطابقة لسبيكة األلمنيوم المختبرة ) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 ( لنسب أجهاد مختلفةthreshold اختبارات مستهل الكلل :( 3جدول رقم specimen number max. stress mpa min. stress mpa δki (mpa m ) stress ratio ( r ) number of cycle to failure hr1 165.69 0.0 7.0 0.0 1× 105 hr2 161.86 0.0 6.25 0.0 1.5 × 105 hr3 138.08 0.0 5.83 0.0 3.9× 105 hr4 124.27 0.0 5.25 0.0 9.9× 105 hr5 110.46 0.0 4.66 0.0 1.6 × 106 hr6 96.65 0.0 4.06 0.0 3.6 × 106 hr7 82.84 0.0 3.5 0.0 1 × 107 hs1 193.31 27.61 7.0 0.1 1 × 105 hs2 138.08 13.80 5.25 0.1 4.2 × 105 hs3 110.46 6.90 4.32 0.1 1.4 × 106 hs4 89.42 5.39 3.5 0.1 5.1 × 106 hs5 77.32 2.76 3.15 0.1 1 × 107 hd1 234.73 69.04 7.0 1104 × 5 1م hd2 179.50 55.23 5.25 1105 × 3.1 1م hd3 151.88 48.32 4.32 0.3 6.8 × 105 hd4 124.27 41.42 3.5 0.3 2.2 × 106 hd5 104.94 30.37 3.15 0.3 5.1 × 106 hd6 82.84 20.17 2.62 0.0 1 × 107 hx1 117104 × 2 0.5 7.0 165.69 11م hx2 248.54 124.27 5.25 0.5 1.2 × 105 hx3 165.69 82.89 3.5 0.5 4.1 × 105 hx4 146.36 71.80 3.15 0.5 8.2 × 105 hx5 124.27 62.13 2.62 0.5 1.7 × 106 hx6 102.18 52.49 2.21 0.5 1 × 107 hy1 207.12 -207.12 8.75 -1 2.8 × 104 hy2 165.69 -165.69 7.0 -1 3 × 105 hy3 138.08 -138.08 5.83 -1 8.5 × 105 hy4 124.27 -124.27 5.25 -1 1.4 × 106 hy5 110.46 -110.46 4.66 -1 1 × 107 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 النموذج يبين أبعاد :(a .2الشكل .المستخدم في االختبار يبين أبعاد الشق المعمول :(b .2الشكل في النموذج المستخدم في االختبار. مقطع عرضي في ريشة طائرة :(1الشكل ( . mi25 عمودية نو مر ائق األلمنيوم لى ةكل سداسي البدق ) سبيكة األلمنيوم ( تقويةأ صاب . مادم غقة الغالف الدارجي 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 718 .شكل النموذج المستخدم في المعايرة يبين :(3الشكل تأثير نسبة أال جهاد على سلوك بدايدة :( 2شكل فددددي اختبددددارات [threshold]مسددددتهل الكلددددل األول لنماذج ذو شق أولي .الطور العالقة بين معامل شدة اإلجهاد :( 5 شكل ونسبة اإلجهاد عند بداية تشقق الكلل في الطور األول لسبيكة األلمنيوم المختبرة. 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 711 عند نسب (threshold)مقارنة النتائج العملية الختبارات بداية مستهل الكلل :( 6 شكل [schmidt & paris]التكهن باالنهيار للباحثان إجهاد مختلفة مع نظرية عند نسب (threshold)مقارنة النتائج العملية الختبارات بداية مستهل الكلل :( 7 شكل .[klensil & lukas] إجهاد مختلفة مع نظرية التكهن باالنهيار الباحثان 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 111 عند نسب (threshold)بداية مستهل الكللمقارنة النتائج العملية الختبارات :( 8 شكل .[mcevily & gregor]إجهاد مختلفة مع نظرية التكهن باالنهيار الباحثان عند نسب (threshold)مقارنة النتائج العملية الختبارات بداية مستهل الكلل :(9 كل ش .[kaisand & mowbrag]اجهاد مختلفة مع نظرية التكهن باالنهيار الباحثان al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 534 numerical analysis of mixed convection flow and heat transfer in a lid-driven octagonal cavity with heating on two sidewalls mushtaq f. al-mensorey department of mechanical engineering, college of engineering, university of al-qadissiya, iraq. email: mushtaq.almensory@gmail.com received 1 september 2015 accepted 21 september 2015 abstract this paper numerically investigates laminar mixed convection flow through an octagonal cavity enclosure where four cases with different positions and directions of its lid-driven were simulated. the lid-driven moves in horizontal rightward and leftward on its upper wall in the first and second cases while it moves vertical upward and downward on its right side wall in the others cases. the numerical study was carried out by solving the governing equations (continuity, momentum and energy), and applying the tri-diagonal matrix algorithm (tdma) method via ansys 11.0 program. four of the eight external walls of the octagonal cavity enclosure are insulation walls and the other four walls were classified into two hot and two cold walls. the mixed convection flow and heat transfer characteristics through isotherms, streamlines and the average nusselt number were considered based on different richardson numbers (ri = 0.01, 1, and 10). the results demonstrated that heat transfer mechanism, the flow pattern and formation of vortices are significantly dependent on values of the richardson number. within the enclosure, the lid-driven movements showed an improvement in the heat transfer rate where the direction of the sliding wall considerably affected the flow and temperature distributions for all values of the richardson number. the nusselt number of the lid-driven increased from 50 with the upward motion to 55 (10 % increase rate) with the downward motion counterpart, and increased from 12 to 17 (40 % increase rate) with the rightward and the leftward motions, respectively. keywords: mixed convection, octagonal cavity, lid-driven, tri-diagonal matrix algorithm (tdma). المختلط في تجويف ثماني ذو غطاء متحرك والجريان التحليل العددي للحمل الحراري وحرارة من جانبين م.م. مشتاق فيصل المنصوري الخالصة: محاكاة أربع تتمحيث , الشكل ثماني ف خالل تجوي المختلطوالجريان الحراري للحمل عدديا البحث, تم انجاز التحليل الهذفي لجدار لنحو اليمين ونحو اليسار االت االربعة تتمثل بحركتين افقيتين الحالمتحرك. طاء ذات مواقع واتجاهات مختلفة للغحاالت حل أجريت الدراسة العددية من خالل للغطاء المتحرك. األيمن للجدار صعودا وهبوطا وحركتين عموديتين غطاء للالعلوي برنامج باستخدام ( tdma)ذات الثالث اقطار خوارزمية الوالطاقة( وتطبيق طريقة ،المعادالت الحاكمة )االستمرارية، الزخم ansys 11.0 جداران لة والجدران األربعة األخرى هموزمعجدران م هالمثمن ثمان جدران الخارجية للتجويف ال. أربعة من مخططات الحرارة و خطوط على مختلط وخصائص انتقال الحرارة التدفق الحراري الر تأثيتمد واعساخنان واخران باردان. انتقال (. أظهرت النتائج أن آلية ri=0.01, 1, and 10ريتشاردسون )لعلى أرقام مختلفة أعدد نسلت بناءومعدل الجريان mailto:mushtaq.almensory@gmail.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 534 معدل حسنت غطاء وان حركة ال تشاردسوندد ريعتدفق فضال عن تشكيل الدوامات تعتمد بشكل كبير على قيم الالحرارة ونمط لجميع التجويف بشكل كبير على تدفق وتوزيع درجات الحرارة داخل المنزلق )المتحرك( يؤثر الجداروان اتجاه انتقال الحرارة ركة الحمع 44الى االعلى الحركة العمودية باتجاه%( مع 05)معدل زيادة 45عدد نسلت ازداد من أنريتشاردسون، اعداد .باتجاه اليسار 01اليمين الى ة االفقية باتجاه الحرك%( مع 55)معدل زيادة 01من سفل واألباتجاه العمودية nomenclature: symbol description unit symbol description (greek symbols) unit cp specific heat j/kg. o c  thermal diffusivity m 2 /s g gravitational acceleration m/s 2  volumetric coefficient of thermal expansion k -1 hf film coefficient μ viscosity n.s/m 2 k thermal conductivity of fluid w/m. °c  kinematic viscosity of the fluid m 2 /s l side length m ρ density of the fluid kg/m 3 nu average nusselt number ψ stream function m 2 /s p pressure n/m 2 {η} unit out ward normal vector pr prandtl number, pr= /   thermal diffusivity m 2 /s q heat flux watt  volumetric coefficient of thermal expansion k -1 {q} heat flux vector μ viscosity n.s/m 2 ri richardson number  kinematic viscosity of the fluid m 2 /s t temperature °c bulk temperature of the adjacent fluid °c ts temperature of the surface of the model °c vx velocity component in x-direction m/s vy velocity component in y-direction m/s x cartesian coordinate in horizontal direction m y cartesian coordinate in vertical direction m introduction the flow and heat transfer of a lid-driven enclosure have taken a considerable interest in the recent years due to their uses in the industrial and thermal instruments such as solar collector, heat exchangers, and cooling of electronic devices [1]. also, the combined mixed convection flow and heat transfer find its applications in float glass production, material processing, crystal growth, metal coating and casting [2]. in order to extensively understand the thermal performance and heat transfer of the mixed convection flow in a lid-driven enclosure, numerous modeling and simulation studies considering both the buoyancy force and the shear force caused by the wall motion of the cavity have been published in the literature. for example, sivasankaran et al. [3] numerically investigated the mixed convection flow in a square cavity with temperature on both vertical sides. they found that the non-uniform heating on one wall gave lower heat transfer rate than that for heating on both walls. cheng and liu [2] also investigated the effect of horizontal and vertical temperature gradients on the flow and heat transfer behavior of mixed convection in a square cavity for different richardson numbers. the laminar mixed convection flow in a square cavity with variations of the average nusselt number was numerically simulated using ansys fluent commercial cfd code by akand et al. [4]. it was noticed that the nusselt number does not clearly vary with increasing richardson number till it approaches the value of 1 with which the average nusselt number rapidly increased. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 531 furthermore, several numerical studies such as ghasemi and aminossadati [5] and ching et al. [6] indicated the heat transfer and fluid flow of mixed convection in a lid-driven triangle enclosure. they found that the thermal performance of a triangle enclosure filled with water strongly affected with the pertinent parameters i.e., direction of the vertical sliding wall, richardson number and solid volume fraction. the effects of inclination angle and richardson number as well as aspect ratio on the heat transfer in a air-filled square cavity were numerically simulated by cheng and liu [7], and on heat transfer in a rectangular inclined channel by marroquin et al. [8]. the heat transfer in an inclined lid-driven enclosure with different magnetic field angles was investigated by mondal and sibanda [9]. the simulation results showed that the increase of inclination angle does not affect the flow and heat transfer when the flow is in a forced convection dominated regime (ri = 0.01). nevertheless, the laminar mixed convection flow and heat transfer inside an octagonal lid-driven enclosure has not been studied yet. thus, this investigation attempts to address the effects of several pertinent parameters such as the horizontal and vertical sliding wall motions, richardson number and the position of lid-driven whether right or top side on the thermal performance and heat transfer of the octagonal cavity. the numerical analysis was done based on solving the governing equations (continuity, momentum and energy equations) and using the tri-diagonal matrix algorithm (tdma) method via ansys 11.0 program. model description and equations an octagonal cavity shape with four insulated walls, two hot and two cold walls as schematically shown in figure 1 was used in this study. the right and left walls of the octagonal cavity are adopted as hot walls with th, and the top and bottom walls are adopted as cold walls with tc. based on the position and the direction of the lid-driven, four different cases were considered in the analysis (see figure 1). the case 1 adopts the horizontal top lid-driven, moving towards the right hand side; the case 2 is the same as the case 1 expect that its lid-driven is moving towards the left hand side. the case 3 considers the vertical right hand side of the lid-driven, moving upwards, and the case 4 is similar to case 3 expect that its lid-driven is moving downwards. the working fluid used in the cavity is air with pr=0.71 and constant properties. the two-dimensional governing equations (continuity, the momentum and energy equations) [3] based on a steady state one phase and laminar incompressible buoyancy-induced flow were solved by using the commercial ansys 11.0 program as follows: continuity equation [3]:     0      y v x v yx  (1) momentum equations [3]:                                           y x v yx x v x g x v y v x v x v   xx p yx (2)                                               y y v yx y v y g y y v y v x y v x v   xy p (3) http://www.sciencedirect.com/science/article/pii/s0017931015007486 http://www.sciencedirect.com/science/article/pii/s0017931015007486 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 534 energy equation [3]:                                     y t k yx t k x t p c y v y t p c x v  x (4) where vx and vy are the velocity components in the x and y direction, respectively; p is the pressure and t is the temperature. the boundary conditions applied to the computational model are assumed as follows: (i) velocity vx =vy = 0 at all constant walls except that of the moved wall (lid-driven). the variables u and –u refer to velocities of the horizontal lid-driven rightward and leftward directions, respectively. the variables v and –v refer to velocities of the vertical lid-driven upward and downward directions, respectively. (ii) temperature t=th is assumed for all vertical right and left walls, and t=tc is assumed for all horizontal top and bottom walls. (iii) stream function stream function for two-dimensional structure is computed based on the following equation [3]: y v     and xv     (5) local nusselt number is chosen as an indicator for the heat transfer rate for the purpose of determining the effect of several parameters on the heat transfer. the local nusselt number is defined as: (6) , and the (hf) is obtained from the following equation (7) richardson number (ri) is dimensionless which can be obtained from: (8) where k lh nu f l        bsf t tthq  2 re gr ri    ul and lttg gr ch    re, )( 3 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 534 3. numerical solution over the computational domain, the grid system was done by unstructured quadratic elements, four nodes which are unevenly distributed close to edge of the octagonal cavity enclosure where higher grid densities are desired as shown in fig. 2. the four nodes quadric elements of 43200 were chosen for their more accurate results and low error tolerance. the governing equations are solved with the convergence iteration of 10 -8 for each variable, and integrated over the domain with use of the exponential interpolation in the mean flow direction inside the finite element. using the finite element ansys 11.0 program and employing the tri-diagonal matrix algorithm (tdma), the governing differential equations (continuity, momentum and energy equations) were solved. the theory of tdma algorithm is based on dividing the problem into a series of tri-diagonal problems. for a completely unstructured mesh, or an arbitrary numbered system, the tdma method reduces to the gauss-seidle iterative method and set of algebraic equations is solved based on the successive under relaxation (sur) technique where the 0.1 is taken as an under relaxation parameter. further details about the tdma method can be found in patanker [10]. the grid independence test is normally applied to ensure the accuracy of the numerical results and determine the approach grid density. in comparison of the average nusselt number with number of nodes, the average nusselt number determined by the eq. 6 is constant when number of nodes reached the 50,000 and higher as shown in fig. 3. results and discussion results of the effects of horizontal and vertical sliding wall motion and the position of lid-driven with three richardson numbers (ri =0.01, 1, and 10) based on magnitudes of the velocity of liddriven on the streamline, temperature and velocity distribution as well as nusselt number inside the octagonal enclosure are presented in the following sections. 1top horizontal rightward motion of the lid-driven (case 1). 1.1 flow field (streamline) figure 4a shows the behavior of vortex of the flow field (flow pattern) for ri = 0.01 that gives high velocity when applying the eq. 8. it can be noticed that a single vortex generated inside the cavity due to the high velocity of lid-driven that resulted in frictional losses and stagnation pressure [2]. the direction of horizontal rightward motion of the lid-driven which moves tangentially with the vortex causing in a clockwise recirculation of the vortex. it can be also observed that the minimum value of the vortex is at the middle of the cavity, and the maximum value of the vortex is near the walls. the region of the fluid streamfunctions near the top moved lid-driven wall is almost smaller than this near the others walls. this behavior is attributed again to the effect of the high velocity of the lid-driven [11]. as ri is increased to 1.0 (fig. 4b), the effect of lid-driven on the flow pattern becomes less stronger and the velocity is slower than that of ri=0.01. however, the mechanicallydriven top lid resulted in the generation of two top and bottom vortices inside the cavity plays an important role in increasing the heat transfer rates. these two vortices are approximately in equal size and generated due to presence of free convection and its role that has become nearly equilibrium with the role of force convection. muthtamilselvan and doh [12] found that richardson number strongly affect the fluid flow and heat transfer in the cavity and the forced convection becomes dominant in the entire cavity. the top vortex moves in clockwise direction due to the effect of lid-driven motion and the effect of hot wall on the left side whereas the bottom vortex moves in counterclockwise due to the role of free convection resulted from the hot wall on the right side. when ri is further increased to 10 (fig. 4c), the effect of the lid-driven motion is also caused in generating two top and bottom vortices but they are in different sizes and rotate in different directions. http://www.sciencedirect.com/science/article/pii/s0307904x13007695 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 555 1.2 isothermal field (temperature distribution) the effect of top horizontal rightward motion of the mechanically-driven lid (case 1) on the isotherm patterns (temperature distribution) for ri = 0.01, 1, and 10 is shown in fig. 4 d-f. in term of ri = 0.01 (fig. 4d), the thermal boundary layer was observed on the hot right and left walls with a small thickness at the top part of the hot right wall. this thickness increased gradually to reach the maximum at the bottom of the same wall. at the hot left wall, the thickness of thermal boundary layer is small at the bottom part of the wall and it increased gradually at the top side of the wall. this is mainly due to the effect of moving air velocity that resulted from the high velocity of the lid-driven which, in turn controls the heat transfer from the hot walls to inside the cavity. with increasing ri to 1 (fig. 4e), the thickness of the thermal boundary layer on the hot wall and the free convection is also increased, leading to maintain a nearly equilibrium between free convection and force convection due to the reduction of the lid-driven velocity. further increasing of ri into 10, the temperature distribution becomes more obvious than that with the ri = 1 as shown in fig. 4f. this is ascribed to decrease the influence of the lid-driven velocity which means that the free convection is the dominant heat transfer method inside the cavity [13]. 1.3 velocity field figure 4g shows the velocity distribution of the fluid flow inside the cavity for ri = 2 regr = 0.01. for this designated ri number, the velocity is the highest and the velocity boundary layer is small near the moved lid-driven wall due to the high velocity of the fluid that restricted the expansion of the layer. on the opposite, it can be seen from the fig. 4g that the velocity value is zero near the others walls and at the middle of the cavity. increasing the ri number to 1.0 (fig. 4h), the impact of the liddriven motion on the velocity is less stronger and hence the region of the velocity boundary layer and the velocity distribution are larger than which for the ri=0.01 due to the role of free convection that becomes more effective in this case. the velocity distribution of the fluid is further increased and the lid-driven velocity is further decreased with increasing ri to 10 as shown in fig. 4i. this is contributed in the dominance of free convection in the cavity and increasing the heat transfer rates, this finding is in conformance with that was noted in khanafer's study [14]. the maximum velocity was noted to be reached at the contact region between the two vortices while the minimum velocity is occurred at the center of two vortices and near all walls except the sliding wall. 2 top horizontal leftward motion of the lid-driven (case 2). 2.1 flow field (streamline) in this case, the effect of the top horizontal leftwards motion of the lid-driven for three richardson numbers (0.01, 1, and 10) on the flow patterns and behavior of vortices of the flow field is illustrated in fig. 5a-c. in terms of ri = 0.01 (fig. 5a), as previously discussed within case 1, a primary vortex is generated inside the cavity due to the high velocity of the lid-driven that moves leftwards, recirculating the vortex counterclockwise. the value of the vortex is maximized in the middle of the cavity and it is minimized near the walls. the region of the fluid streamfunctions near the sliding lid-driven wall is approximately smaller than this near the others walls. this is due to the effect of the high velocity of the lid-driven. when ri is increased to 1.0 (fig. 5b), the effect of lid-driven on the flow field becomes less effective and the velocity becomes lower than that with ri=0.01. however, this mechanically-driven top lid motion resulted in building two vortices inside the cavity enclosure due to the role of free convection which becomes nearly equilibrium with the role of force convection. these two upper-right and lower-left vortices are almost having similar sizes. the upper-right vortex moves counterclockwise owing to the effect of lid-driven motion and al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 550 the effect of hot wall on the right side while the lower-left vortex moves clockwise due to the role of free convection that resulted from the hot wall on the left side. as ri is further increased to 10 (fig. 5c), the effect of the lid-driven motion is also resulted in building two upper-right and lowerleft vortices but they are in different sizes and rotate in different directions. 2.2 isothermal field (temperature distribution) the effect of top horizontal leftwards motion of mechanically-driven lid (case 2) on the isotherm field (temperature distribution) for ri = 0.01, 1, and 10 is shown in fig. 5 d-f. for the ri = 0.01 (fig. 5d), the thermal boundary layer was seen on the hot right and left walls with a minimum thickness at the lower part of the hot right wall and gradually increased to reach the maximum at the upper part of the same wall. at the hot left wall, the thickness of thermal boundary layer is small at the upper part of the wall and it gradually increases at the lower part of the same wall. this is mainly due to the effect of velocity of the moved air that induces dominant of force convection in the entire cavity. with increasing ri to 1 (fig. 5e), the thickness of the thermal boundary layer on the hot wall is also increased due to the reduction of the lid-driven velocity which leads to increase the free convection and maintain the nearly equilibrium between free convection and force convection. further increase of ri to 10, the temperature distribution becomes more obvious than that with the ri = 1 as shown in fig. 5f. this is ascribed to vanish the role of the lid-driven velocity which means that the free convection is dominant inside the entire cavity. 2.3 velocity field figure 5g shows the velocity distribution of the fluid flow inside the cavity for ri = 0.01 where the velocity is the highest and the velocity boundary layer is small near the moved lid-driven wall. in contrast, it can be seen from the fig. 5g that the velocity value is zero near the others walls and at the middle of the cavity. increasing ri to 1.0 (fig. 5h), the role of the lid-driven motion on the velocity is less effective and hence the region of the velocity boundary layer and the velocity distribution are larger than which for ri=0.01 owing to the role of free convection that becomes more effective in this case. the velocity distribution of the fluid is further increased and the liddriven velocity is further decreased with increasing ri to 10 as shown in fig. 5i. this is contributed in the dominance of free convection in the cavity and increasing the heat transfer rates. the maximum velocity was noted to be reached at the contact region between the two vortices while the minimum velocity is occurred at the center of two vortices and near all walls except the sliding wall. 3 right vertical upward motion of the lid-driven (case 3). 3.1 flow field figure 6a shows the flow pattern (streamline) for ri=0.01 and the right vertical upward motion of the lid-driven that moves in a high velocity. it can be seen that a large single vortex is generated inside the entire cavity which is rotated anticlockwise direction. the minimum value of the vortex (fluid streamfunctions) seems to be near the walls and its region which is near the hot right moved lid-driven wall, is almost smaller than this near the others walls while the maximum region is at the middle of the cavity enclosure. when ri=1 (fig. 6b), the single vortex seems to be a semi-elliptical shape approaching the right sliding wall due to the increased effective of the free convection. meanwhile, the region of the minimum streamfunction in the hot left wall of the cavity increased. as the ri increased to 10 (fig. 6c), the effect of free convection in the entire cavity becomes dominant, leading to increase the deformation of the vortex which discussed in the previous case (fig. 6b) that resulted in separating the single vortex into two vortices [7]. the generated vortices al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 551 are in different sizes and rotating in two different directions. the larger vortex locates close to the hot sliding wall and rotates anticlockwise whereas the other vortex locates on the hot left wall and rotates clockwise. similarly, this was also revealed in the esfe et al.'s work [15] where they were seen the vortex migration to higher positions inside the cavity occurred and higher heat transfer rates obtained due to the change in the ri number and then the lid-driven velocity. 3.2 isothermal field the isothermal field (temperature distribution) for ri=0.01 is shown in fig. 6d. it can observe that the thermal boundary layer is contiguous on the hot right sliding wall and it is widely expanded to reach its maximum thickness at the adjacent insulated top wall. this is attributed to the direct effect of the mechanically-driven lid on the hot right wall. however, this layer is in its minimum thickness at the hot top left wall and it is gradually expanded approaching the bottom of the same wall. when ri=1 (fig. 6e), the temperature distribution is more obvious than that for ri = 0.01 due the reduced velocity of the lid-driven that caused in the occurrence of semi-equilibrium case between the free and force convection flow. with further increase of ri to 10 (fig. 6f), the temperature distribution became semi symmetric around the vertical axis owing to the decreased effect of a lid-driven velocity. in other words, the free convection dominates the entire cavity. 3.3 velocity field figure 6g shows the velocity distribution of the fluid flow inside the cavity for ri = 0.01 where the velocity is the highest and the thickness of velocity boundary layer is small near the right upwards sliding wall whereas the velocity value is zero near the others walls and at the middle of the cavity. when ri = 1 (fig. 6h), the effect of lid-driven velocity is lesser and the velocity distribution inside the entire cavity is wider than those for ri=0.01 owing to the role of free convection that becomes more effective. consequently, the thickness of velocity boundary layer is expanded on the sliding wall and the stagnation region is increased at the hot bottom left wall. moreover, the lid-driven velocity is further decreased and the velocity distribution of the fluid is further increased with increasing ri to 10 as illustrated in fig. 6i. this is ascribed to the free convection that dominated the entire cavity. the maximum velocity emerged to be in the middle of the octagonal enclosure and the minimum velocity is at the centers of the generated vortices and near all the walls except the hot right lid-driven. the velocity distribution is a semi-symmetric around the vertical axis with a small deformation due to the force convection. 4 right vertical downward motion of the lid-driven (case 4). 4.1 flow field figure 7a shows the flow field for ri=0.01 under right vertical downward motion of a lid-driven. it is demonstrated that a large single vortex is generated inside the cavity rotates clockwise due to the high velocity of the sliding wall. the minimum value of the vortex (fluid streamfunctions) seems to be in the middle of the cavity while the maximum value is near the walls. the minimum region of the flow pattern is near the hot right downwards sliding wall and the maximum region is near the others walls due to the dominance of the force convection [16]. with increasing ri to 1, the large single vortex is split into three longitudinal vortices (see fig. 7b) with different sizes due to the increased effect of free convection that resulted in a semi-equilibrium between free and force convection heat transfer mechanism. the largest vortex locates near the hot left sliding wall and moves in clockwise direction for the difference in hot and cold temperatures on the walls. the second vortex generated due to the effect of the free and force convection, locates in the middle of the cavity and rotates anticlockwise. the third vortex that lies near the hot right wall and rotates al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 553 clockwise, generated owing to the force convection. the latter vortex is almost vanished and the two former vortices are enlarged with increasing ri to 10 as shown in fig. 7c. in this case, the free convection is dominated in the cavity. 4.2 isothermal field figure 7d shows the thermal boundary layer for ri=0.01 is contiguous on the hot right sliding wall and widely expanded to reach its maximum thickness at the adjacent insulated bottom wall due to the direct effect of the mechanically-driven lid on the hot right wall. however, the minimum thickness of the layer is shown on the hot bottom left wall and it is gradually expanded approaching the top of the same wall. as ri increased to 1 (fig. 7e), the temperature distribution is more obvious than that for ri = 0.01 due the decreased velocity of the lid-driven that resulted in the occurrence of semi-equilibrium case between the free and force convection. with further increase of ri to 10 (fig. 7f), the temperature distribution became semi symmetric around the vertical axis due to the reduced effect of a lid-driven velocity which means that the free convection dominated the cavity. 4.3 velocity field the velocity distribution of the fluid flow inside the cavity for ri = 0.01 is shown in fig. 7g. the velocity is the highest and the thickness of velocity boundary layer is small near the right downward lid-driven while the velocity value is zero near the others walls and at the middle of the octagonal cavity. when ri=1 (fig. 7h), the effect of lid-driven velocity is lesser and the velocity distribution inside the cavity is wider than that for ri=0.01 due to the role of free convection that becomes more effective. as a result, the thickness of velocity boundary layer is expanded on the sliding wall and the stagnation region is increased at the hot bottom right wall. additionally, the velocity is further reduced and the velocity distribution of the fluid is further increased when ri = 10 as shown in fig. 7i. this behavior is occurred for the free convection that dominated the entire cavity. the maximum velocity emerged to be in the middle of the octagonal cavity and the minimum velocity is at the centers of the vortices and near all the walls except the sliding wall. the velocity distribution is a semi-symmetric around the vertical axis with a small deformation due to the force convection. heat transfer field the variation in the nusselt number (nu) of the mixed convection flow for ri= 0.01, 1, 10 and different locations along the hot right wall was calculated and compared in fig. 8. for which, four different directions i.e., rightward, leftward, upward, and downward of the lid-driven were considered. the designated hot right wall was equally partitioned into numerous grids in order to calculate the average nu in different positions. the calculated nu exhibited that the heat transfer rate at the hot right wall increases with decreasing ri. the lid-driven moving towards left (case 2) had a better heat transfer rate than the lid-driven moving rightwards (case 1). this is due to the increased buoyancy effect and the increased air velocity inside the cavity [2]. similarly, the liddriven moving downwards (case 4) had a better heat transfer rate than the lid-driven was moving to upward (case 3). the vertical motion of the lid-driven whether upwards or downwards significantly increases the heat transfer rates compared to the horizontal motion (rightwards or leftwards) that exhibited a less effective on the heat transfer rates. in light of the relation of fluid motion and shape of the octagonal cavity on the heat transfer rate; it was shown that such a shape tends to generate a single circular vortex with the use of smaller ri. with higher ri values, the single vortex separated al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 555 into two or three vortices due to the reduction of velocity. this is resulted in significant increases of the heat transfer rates. conclusion the mixed convection flow and heat transfer in a lid-driven octagonal cavity filled with air fluid was numerically studied using ansys 11.0 program. the horizontal rightwards, leftwards and vertical, upwards and downwards directions were considered. the effect of different positions and directions of the sliding wall and richardson number on the flow, temperature fields and heat transfer rate was examined. the results revealed the following findings: the flow pattern, temperature and velocity have significantly changed with changing ri numbers and the motion of the lid-driven. any motion in the lid-driven showed an improvement in the heat transfer rate of the cavity. for all richardson numbers, the vertical downward and the horizontal leftward lid-driven motions proved to have higher heat transfer rates compared to the vertical upward and the horizontal rightwards lid-driven motions, respectively. the higher heat transfer rates increased with decreasing the richardson number for the strengthening of flow circulation due to effects of the sliding wall motion. references [1] chin-hsiang cheng, chin-lung chen, " buoyancy-induced periodic flow and heat transfer in lid-driven cavities with different cross-sectional shapes", international communications in heat and mass transfer 32 (2005) 483-490. 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[16] m. borhan uddin, m.m. rahman, m.a.h. khan, talaat a. ibrahim, " effect of buoyancy ratio on unsteady thermosolutal combined convection in a lid driven trapezoidal enclosure in the presence of magnetic field", computers & fluids, 114 (2015) 284–296. insulation walls insulation walls insulation walls insulation walls insulation walls insulation walls g tc tc th th case 4 g tc tc th th case 1 u g tc tc th th case 2 u g tc tc th th case 3 v v figure (1): physical model and boundary conditions for four cases. lid-driven lid-driven lid-driven lid-driven http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/journal/07351933 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http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/journal/00457930 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 554 figure (2): a distinctive grid distribution with quadratic elements. 52.84 52.85 52.86 52.87 52.88 52.89 52.90 52.91 52.92 52.93 0 10000 20000 30000 40000 50000 60000 figure (3): relationship between the average nusselt number and number of nodes. n u number of nodes al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 551 velocity distribution body contour (m/s) figure (4): showing the streamlines, isotherms and the velocity body contours for top horizontal rightward motion of the lid driven motion with ri = 0.01, 1, and 10. stream function body contour isothermal body contour (kelvin) u u u u u u u u u (a) (b ) (c) (d ) (e) (f) (g) (h ) (i) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 554 velocity distribution body contour (m/s) figure (5): showing the streamlines, isotherms and the velocity body contours for top horizontal leftward motion of the lid driven motion with ri = 0.01, 1, and 10. isothermal body contour (kelvin) u stream function body contour (m 2 /s) u u u u u u u u (a) (b ) (c) (d ) (e) (f) (g) (h ) (i) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 554 stream function body contour v v v isothermal body contour (kelvin) v v v velocity distribution body contour (m/s) figure (6): showing the streamlines, isotherms and the velocity body contours for right vertical upward motion of the lid-driven motion with ri = 0.01, 1, and 10. v v v (a ) (b ) (c) (d ) (e) (f) (g ) (h ) (i) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 545 stream function body contour v v v isothermal body contour (kelvin) v v v velocity distribution body contour (m/s) figure (7): showing the streamlines, isotherms and the velocity body contours for right vertical downward motion of the lid-driven motion with ri = 0.01, 1, and 10. v v v (b ) (c) (d ) (e) (f) (g) (h ) (i) (a) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 540 0.000 0.005 0.010 0.015 0.0 10.0 20.0 30.0 40.0 50.0 60.0 ri=0.1 ri=1 ri=10 0.000 0.005 0.010 0.015 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 ri=0.1 ri=1 ri=10 figure (8): variation of the local nu along the hot right wall for cases 1, 2, 3, and 4 and ri=0.01, 1, and 10. g tc tc th th u (b) top horizontal leftwards motion of the lid driven 0.000 0.005 0.010 0.015 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 ri=0.1 ri=1 ri=10 g tc tc th th u (a) top horizontal rightwards motion of the lid driven n u n u 0.000 0.005 0.010 0.015 0.0 10.0 20.0 30.0 40.0 50.0 60.0 ri=0.1 ri=1 ri=10 g tc tc th th g tc tc th th v (c) right vertical lid driven with moving upward (d) right vertical lid driven with moving downward v n u n u chapter five al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 492 estimation of dokan reservoir reliability using stream flow data generation techniques ruqaya k.m. al-masudi college of engrg., babylon univ., babil, iraq ruqaya2008@yahoo.com abstract in the present study, two procedures of capacity-yield are applied to estimate the reliability of dokan reservoir using data generation techniques. these procedures are the probability matrix (gould) procedure, and the behavior analysis. vulnerability, and resilience, are also calculated in the second procedure .the data is generated by using four approaches ,namely ,thomas-fiering model with log –transformation (tf-log), two-tier model (ttm), modified two-tier model (mttm) and modified fragment model (mfm).these models are tested and compared with the historical data. it is concluded that among these four procedures the thomas-fiering model with log –transformation is the most appropriate for representing the dokan reservoir inflow .three factors are examined to determine their influence on the minimum storage estimate .these are the length of stochastically generated sequence, the initial state of storage ,and the starting month. the results reported here show that sequences as long as 10,000 years or more may be needed to minimize the effects of these factors. ستخلصمال . هاذه بنساتخدا البنناانا المدلاد لتخمانط اتتمنيياة اا ا ين ان اإلطاقل -طبقت طريقتان ناط طارل ال ا ةفي هذه الدراسة تم تدلناد البنناانا بنساتخدا ن اتتمنيا تلى الطريقاة اخانار .تح ب فالض ن تحلنل ال لدك.المرناة ن طريقة الطرل هي طريقة جدلد لم دلاة تانير ا-تاد،طريقاة تنير-تاد ، طريقاة نع اساتخدا التحاديقا اللدرنريتمناة فنيراك-ثدننسريقة طرل هذه الطرل هي ط أرب ة الم دلة . استخدنت البننانا المدلد لمقنراة النتنئج نع النتنئج المح دبة بنساتخدا البنناانا التنريخناة نفاي ا ا فرا منات ،نطريقة نع استخدا التحديقا اللدرنريتمنةفنيراك -ثدننس ةطريق إ فنمن بننهن ناستنتج لبنناناالدقت لمقنراة اتنئج الطرل اخرب ة لتدلند ا ين ن . لتمثنل التصنريف الداالة لخ ا اخفضلهي التصانريف المدلاد ، حنلاة هذه ال دانل هي طدل سل الة.تلى تخمنط الخ المطلدب تأثنرهن إليجنيثقثة تدانل تم فحصهن سانة 10,000سل لة جرين بحادني إلىهذه الدراسة بأاه يحتنج المقدنة في ا ، نالبدا بشهر نن. أظهرا النتنئج الخ يط اخنلي للخ هذه ال دانل. تأثنرلتقلنل أ ثر أن key words: stream flow data generation, reliability of reservoir, reservoir probability of failure. introduction reservoirs are built to supplement future river flows, but no-one can forecast what these will be. it is unlikely that history will repeat itself, yet many procedures use only the historical record. to overcome this dilemma, it is often useful to generate synthetic stream flow data .stochastic data generation provides designers and analysis of resource systems with alterative sequences of stream flow having the same statistical properties as the historical record. it is then possible to determine the storage capacity (or other design parameter) for each sequence, and thus provide the designer with a al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 492 distribution of the values .this process gives an idea of the confidence which can be placed on the adopted design value. “synthetic flows or stochastic data” do not improve poor records but merely improve the quality of designs made with whatever records are available. in the present study, two procedures of capacity-yield are applied to estimate the reliability of dokan reservoir by using four data generation techniques. the dokan reservoir the dokan dam is located at about 60 km from the northen west of al-sulaimania town and at about 300 km from karkok governorate. the main purposes of the dokan project are to store and regulate the abundant water of the lesser zab river, a tributary of the tigres river, by creating a large scale reservoir, to supply irrigation water required in the area downstream of the dam, and to control discharges downstream by impounding and regulating floods. in addition to the abovementioned purposes, the discharge and head obtained by the dam are to be utilized for power generation for effective use of hydraulic energy, thereby making this a multi-purpose, for irrigation, flood control, and power generation (iraqi ministry of water resources,2007). estimation of reliability using data generation techniques a number of generation models are used to evaluate the reliability of a reservoir by behavior analysis and gould’s procedure. these generation models are designated by the following: tflog=thomas-fiering monthly model with log transformation; ttm=two-tier model using markovian annual flows; mttm=modified two-tier model; mfm=modified fragment model;. before using the generated data in the estimation of dokan reservoir reliability, it is necessary to make sure that those generated sequences are extracted from the same population of the historical sample. this can be done by verifying the model used in the generation by the following tests: 1. comparison of the statistical parameters computed from the generated data with the actual values of those statistics computed from the historical records, for the purpose of simplicity, the relative error (as a percentage) was calculated (srikanthan and mcmahon,1982) from the following equation: %100 )( )(    valuehistoric valuehistoricalgenerated figures (1) to (6) show the relative error of mean, standard deviation, coefficient of variation, coefficient of skewness, correlation coefficient and regression coefficient, respectively. it can be seen that the tf-log,ttm and mttm models preserved parameters better than the mfm model. however, there was only a small difference between the tf-log and mttm results, especially for coefficient of variation, coefficient of skewness , correlation coefficient and regression coefficient. there is a worthiness to say here that it is not a condition that the model preserved the statistical parameters to be the best model for reliability, vulnerability and resilience estimation but this will give more trust for this estimation. 2. comparison of cumulative probability curves for the two series from historical and generated data.figure (7) shows the cumulative probability curves for dokan reservoir inflows based on historical and generated data. this figure indicates that all the transformations are not significantly different from that produced from historical data. 3. comparison of the proportion of negative flows. the model is acceptable so long as the proportion of negative flow is not greater than 5% (mcmahon and mein, 1986). table (1) shows a comparison between the statistical properties (mean, standard deviation and correlation coefficient) of all generated series by tf-log, ttm, mttm, mfm, and that of historical relative error al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 492 series. this table indicates that the monthly statistical parameters of tf-log and mfm generated data are very close to those of historical data. table (2) shows the comparison between monthly statistical parameters (mean, standard deviation and correlation coefficient) of the generated data by tf-log, ttm, mttm, mfm and that of historical data. all the monthly means of the generated data pass the t-test and the f-test at 95% significant probability limit. table (2) shows the results of statistical tests (t-test and f-test) for the monthly means and standard deviations, respectively, for the generated data. it can be seen that the average failure in monthly means and monthly standard deviation is 0% for all generated series. analysis of the results figure (8) shows the effect of the number of years used in the analysis on the estimation of reliability by behavior procedure for the four methods of generation used in this research. it could be seen that the (55) year estimation series of reliability diverges away ,this may be to the longer series. thus, the use of the longest and longest series will converge the results one to another. figure (9) shows the same effect of figure (8) but by using the gould’s procedure. this figure indicates that the sensitivity of results by using gould’s procedure will be less than of behavior procedure .also, it could be seen that gould’s estimation of reliability almost less than the behavior estimation. figure (10) shows that the estimated vulnerability tends to move on approximately straight line and converge from one model of generation to another under the effect of time series length with increasing the monthly release from the reservoir. figure (11) also shows that there is a high variation in the estimated value of resilience under the effect of number of years used in the analysis and, as in reliability, the longest and longest series will converge the results. as a result, the use of longest series in the behavior analysis to estimate the reliability, vulnerability and resilience of reservoir will make the results more accurate because of the starting month problem and the assumption of initially full will be overcome by using such series. figure (12) shows the reliability-yield reservoir relationship depending on behavior and gould’s procedure using both historical and generated data .figure (12-a) indicates that the tf-log give a smaller reliability estimate than other models where ttm and mttm results converges to the results based on the historical data which considered to be reasonable one by many researcher in literature. this means that the ttm and mttm could be considered the best to represent the inflow of dokan reservoir. behaviour estimation of reliability is almost more than the case of using gould's procedure for dokan reservoir. the 95% reliability, which is considered to be an acceptable limit of reliability(mcmahon et. al ,1972), could be obtained with a release of (72-80)% and (75-80)% from the mean flow depending on behaviour analysis and gould's procedure ,respectively. figure (13) shows the vulnerability-yield relationship and indicates that the vulnerability of reservoir increasing and tends to be a straight line with the increasing of the release (decreasing the reliability) by using the historical and generated data. figure (13) also shows the resilience-yield relationship and indicates that there is a high difference between the historical and generated data estimate. it is also obvious that the reservoir resilience increase with the increasing of the release from the reservoir. effect of starting month on storage estimates to examine the effect of starting month on storage size are calculated by starting the analysis in different months for two draft cases (55% and 75% of mean flow) at 95% reliability using both behavior procedure and gould analysis with historical data. the storage estimates are plotted for al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 492 comparison in figure (14). it is observed from the results that the storage size estimated through behavior analysis vary little with starting month. figure(15) shows the vulnerability and resilience respectively which were constant with any starting month for both cases .on the other hand gould’s storage estimates differed markedly for different month . one way to overcome this impact is to use long sequences of synthetic month data in the analysis as shown in figure (16). it can be noted from this figure that the gould storage estimates varied more than the behavior estimates which were constant for all cases .however, the gould estimates based on generated data were considerably less variable than those calculated using historical data. effect of inflow sequence length on storage estimates this section investigates the dependence of estimates of reservoir storage capacity derived using behaviour analysis and gould’s proccedure on the length of inflow sequence used for overyear reservoir simulation.for each method of reliability estimation, 20 different sequence lengths are generated varying from 200 to 10,000 years and the required reservoir storage for each sequence is then predicted. it follows from the stochstic theory of storage that the reliability of a reservoir operating on a single realization of the inflow process can theoretically attain steady state only as the sequence length approaches infinity(moran,1959, quoted in abdul-bari,(2006)). the overyear storage estimates as shown in figures (17) and (18) are significantly influenced by the length of inflow sequence analyzed. in order to remove the influence of inflow sequence length on the storage estimates by the above methods, the inflow sequence is generated for 10,000 years because of the storage estimates approached a stationary level by about 6,000 years or more for the methodes examined. effect of initial conditions on storage estimates the initial reservoir condition (c0) is typically assumed to be full (mcmahon and mein,1978), although any initial condition ranging form empty to full could be used.figure (19,a) showes plots of the behaviour storage estimates againest yield using historical data to explore the influence of the initial full and empty reservoir conditions.to overcom the effectes of the assumed initial conditions, a sequence length of at least 10,000 years would be required because the initially full assumption curve is converged to the initially empty curve for all generated model as shown in figure (19,b-e). conclusions for this study , the following conclusions are deduced: 1. after using four data generation models, it becomes clear that the thomas-fiering with log transformation is the best for generating monthly inflows of dokan reservoir among the other models. 2. based on the historical data, the gould storage estimates vary more widely with starting month than the behaviour estimates which are approximately constant for all cases as well as al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 492 the vulnerability and resilience.however, the effect of starting month is relatively substantial in gould estimates using generated data. 3. the variation in storage estimate becomes neglectable by using sequence length of 6,000 years or more for the methodes examined. 4. the influence of the initial condition (full or empty) in the behaviour analysis is effectively nullified for inflow sequences longer than about 10,000 years. references mein, r.g., and mcmahon, t.a.(1978):"reservoir capacity and yield procedures.", development in water science9, elsevier, amsterdam. srikanthan, r. and mcmahon, t.a.(1985a):"gould’s probability matrix method .1. the starting month problem.", j. of hydrology, vol.77,pages 125-133. mein, r.g., and mcmahon, t.a.(1986):"river and reservoir yield.”, water resources publication, ft. collins, colorado. madhloom,h.m.(2000): "probability of failure of al-adhaim reservoir. ", m.sc.thesis, college of engineering,babylon university,iraq. al-fatlawi, t.j.(2003): "evaluation the probability of failure of haditha reservoir.", m.sc. thesis,college of engineering,babylon university,iraq. hussein, a.k.,(2005):" probability of failure to adhaim reservoir.", j. of babylon university, engineering sciences vol.10, no.5, pages 922-934. abdul-bari ,w.h.,(2006): "reliability of iraqi reservoirs. ",m.sc.thesis,college of engineering,babylon university,iraq. ministry of water resources.,(2007):" planning report on dokan dam project." series model mean (m 3 /sec.) standard deviation (m 3 /sec.) cs r negative flows (%) max. flow (m 3 /sec.) hist. 206 290.84 1.9 0.62 0 5470 gen. tf-log 203.49 221.57 3.43 0.71 0 2608 ttm 215.84 261.56 2.66 0.67 0 1811 mttm 199.43 230.91 3.11 0.59 0 1910 mfm 215.89 259.24 2.14 0.99 0 1737 table 1: statistical properties of historical and generated data. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 499 d e c . 1 5 2 .5 8 1 4 4 .6 4 1 6 3 .8 6 1 5 6 .4 0 2 1 2 .1 2 1 1 0 .3 6 8 6 .7 7 3 1 2 4 .8 7 1 0 0 .6 7 1 0 7 .4 0 0 .7 0 4 0 .5 4 9 0 .7 1 0 0 .6 1 6 1 .0 0 n o v . 1 0 2 .0 6 9 7 .3 6 1 1 0 .9 6 1 0 3 .2 5 7 3 .1 5 6 3 .9 1 5 8 .8 3 1 0 5 .4 6 7 3 .5 6 3 7 .0 4 0 .4 6 2 0 .5 9 8 0 .7 2 1 0 .6 4 2 0 .9 9 9 o c t. 5 8 .8 9 5 8 .7 4 7 2 .7 2 6 1 .0 4 4 7 .5 5 2 2 .7 8 2 5 .6 3 6 8 .2 8 3 2 .5 1 2 4 .0 7 0 .5 4 1 0 .7 2 1 0 .8 3 1 0 .5 9 0 1 .0 0 s e p . 5 4 .7 8 5 4 .6 6 6 0 .2 9 5 4 .7 9 4 3 .8 9 2 4 .0 6 2 5 .3 0 5 1 .0 4 2 9 .7 1 2 2 2 .2 2 0 .6 3 2 0 .5 7 2 0 .3 7 7 0 .3 1 1 1 .0 0 a u g . 6 1 .2 7 6 3 .6 0 6 4 .0 4 5 7 .7 3 4 3 .8 9 3 7 .5 5 3 6 .5 7 6 9 .2 0 5 0 .8 6 2 2 .2 2 0 .7 9 5 0 .9 1 3 0 .8 3 0 0 .8 6 5 1 .0 0 ju l. 7 6 .1 8 8 1 .6 9 9 6 .4 8 8 3 .1 4 5 4 .8 6 3 8 .5 0 3 8 .9 6 8 3 .3 8 4 6 .5 8 2 7 .7 7 0 .7 7 8 0 .8 5 1 0 .8 0 8 0 .4 7 1 1 .0 0 ju n . 1 3 6 .0 9 1 4 2 .7 3 1 5 8 .7 7 1 5 1 .9 1 9 8 .0 3 6 7 .8 0 7 1 .0 1 1 1 5 .1 5 9 3 .4 2 5 1 .1 2 0 .8 5 9 0 .9 2 0 0 .9 0 0 0 .7 9 6 0 .9 1 7 m a y 2 9 5 .7 1 2 8 7 .6 5 3 0 2 .7 4 2 8 9 .7 8 2 3 7 .7 3 1 5 9 .6 8 1 4 7 .0 2 2 2 3 .1 2 1 8 3 .6 0 1 2 0 .3 7 0 .9 2 0 0 .9 2 4 0 .9 2 2 0 .8 1 5 0 .9 1 7 a p r. 5 7 0 .8 9 5 7 9 .3 7 4 5 3 .0 8 4 2 9 .9 1 4 7 3 .0 2 7 2 4 .4 2 3 9 3 .0 0 4 7 9 .4 9 4 7 9 .6 9 2 4 2 .3 1 0 .2 8 4 0 .5 0 4 0 .1 8 8 0 .2 0 5 0 .9 9 9 m a r. 4 6 2 .1 5 4 3 5 .5 8 5 0 8 .3 0 4 6 0 .5 1 7 4 2 .4 4 3 1 2 .9 8 2 2 0 .4 5 3 4 9 .8 1 2 5 8 .8 1 3 7 5 .9 1 0 .3 7 9 0 .5 9 0 0 .3 4 8 0 .3 8 8 0 .9 9 9 f e b . 3 0 9 .1 1 2 9 8 .4 7 3 5 4 .4 5 3 2 7 .5 6 4 0 2 .3 0 1 5 5 .0 1 1 7 1 .5 5 2 5 7 .7 4 1 8 2 .8 3 2 0 3 .7 0 0 .4 7 7 0 .6 4 2 0 .6 4 6 0 .6 0 0 1 .0 0 ja n . 1 9 2 .4 6 1 9 6 .7 8 2 4 3 .0 2 2 2 1 .8 9 1 6 0 .9 2 1 0 5 .6 3 1 0 9 .7 4 1 8 5 .2 9 1 3 8 .4 6 8 1 .4 8 0 .6 6 7 0 .7 6 7 0 .8 0 2 0 .7 4 5 1 .0 0 s e ri e s h is t. t f -l o g t t m m t t m m f m h is t. t f -l o g t t m m t t m m f m h is t. t f -l o g t t m m t t m m f m m e a n (m 3 /s e c .) s ta n d a rd d e v ia ti o n (m 3 /s e c .) c o rr e la ti o n c o e ff ic ie n t t a b le 2 : m o n th ly s ta ti st ic a l p a ra m e te rs o f h is to ri c a l a n d g e n e ra te d m o n th ly d a ta . al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 033 oct nov dec jan feb mar apr may jun jul aug sep time (month) -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 r e la ti v e e r r o r (% ) tf-log ttm mttm mfm oct nov dec jan feb mar apr may jun jul aug sep time (month) -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 r e la ti v e e r r o r (% ) tf-log ttm mttm mfm oct nov dec jan feb mar apr may jun jul aug sep time (month) -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4 r e la ti v e e r r o r (% ) tf-log ttm mttm mfm oct nov dec jan feb mar apr may jun jul aug sep time (month) -2.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 r e la ti v e e r r o r (% ) tf-log ttm mttm mfm oct nov dec jan feb mar apr may jun jul aug sep time (month) -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 r e la ti v e e r r o r (% ) tf-log ttm mttm mfm oct nov dec jan feb mar apr may jun jul aug sep time (month) -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4 r e la ti v e e r r o r (% ) tf-log ttm mttm mfm figure 1: relative error of the mean. figure 2: relative error of the standard deviation. figure 3: relative error of the coefficient of variation. figure 4: relative error of the coefficient of skewness. figure 5: relative error of the correlation coefficient. figure 6: relative error of the regression coefficient. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 033 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 inflow (cumecs) 0 10 20 30 40 50 60 70 80 90 100 p r o b a b il it y o f fl o w l e ss t h a n ( % ) his tfm 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 inflow (cumecs) 0 10 20 30 40 50 60 70 80 90 100 p r o b a b il it y o f fl o w l e ss t h a n ( % ) his ttm 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 inflow (cumecs) 0 10 20 30 40 50 60 70 80 90 100 p r o b a b il it y o f fl o w l e ss t h a n ( % ) his mttm 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 inflow (cumecs) 0 10 20 30 40 50 60 70 80 90 100 p r o b a b il it y o f fl o w l e ss t h a n ( % ) his mfm 50 60 70 80 90 100 yield (% mean flow) 80 85 90 95 100 r e li a b il it y ( % ) thomas-fiering model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 80 85 90 95 100 r e li a b il it y ( % ) two-tier model 55 year 220 year 550 year 770 year figure 7: cumulative probability function for dokan reservoir inflow using both historical and generated data. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 034 50 60 70 80 90 100 yield (% mean flow) 75 80 85 90 95 100 r e li a b il it y ( % ) modified two-tier model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 80 85 90 95 100 r e li a b il it y ( % ) modified fragment model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 80 85 90 95 100 r e li a b il it y ( % ) thomas-fiering model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 80 85 90 95 100 r e li a b il it y ( % ) two-tier model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 75 80 85 90 95 100 r e li a b il it y ( % ) modified two-tier model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 80 85 90 95 100 r e li a b il it y ( % ) modified fragment model 55 year 220 year 550 year 770 year figure 8: effect of number of years used in generation on the estimation of reliability by behavior procedure. figure 9:effect of number of years used in generation on the estimation of reliability by gould’s procedure. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 030 50 60 70 80 90 100 yield (% mean flow) 0 100 200 300 400 500 600 v u ln e r a b il it y ( m il li a r d c m ) thomas-fiering model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 0 100 200 300 400 500 600 v u ln e r a b il it y ( m il li a r d c m ) two-tier model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 200 300 400 500 600 v u ln e r a b il it y ( m il li a r d c m ) modified two-tier model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 100 200 300 400 500 600 v u ln e r a b il it y ( m il li a r d c m ) modified fragment model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 0 5 10 15 20 25 30 r e si li e n c e ( m o n th ) thomas-fiering model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 0 5 10 15 20 25 30 35 40 r e si li e n c e ( m o n th ) two-tier model 55 year 220 year 550 year 770 year figure (10): effect of number of years used in generation on the estimation of vulnerability. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 032 50 60 70 80 90 100 yield (% mean flow) 0 40 r e si li e n c e ( m o n th ) modified two-tier model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) 0 5 10 15 20 25 30 r e si li e n c e ( m o n th ) modified fragment model 55 year 220 year 550 year 770 year 50 60 70 80 90 100 yield (% mean flow) a. behavior procedure 75 80 85 90 95 100 r e li a b il it y ( % ) tf-log ttm mttm mfm his. 50 60 70 80 90 100 yield (% mean flow) b. gould's procedure 75 80 85 90 95 100 r e li a b il it y ( % ) tf-log ttm mttm mfm his. 50 60 70 80 90 100 yield (% mean flow) 0 100 200 300 400 500 600 v u ln e r a b il it y ( m il ia r d c u .m ) tf-log ttm mttm mfm his. 50 60 70 80 90 100 yield (% mean flow) 0 5 10 15 20 25 30 35 40 r e si li n c e ( m o n th ) tf-log ttm mttm mfm his. figure 11: effect of number of years used in generation on the estimation of resilience. figure 12: reliability-yield relationship depending on behavior and gould’s procedure using both historical and generated data (770 years of generation). figure 13:vulnerability-yield and resilience-yield relationships depending on both historical and generated data (770 years of generation). al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 032 jan feb mar apr may jun jul aug sep oct nov dec starting month 800 900 1000 1100 1200 1300 1400 1500 s to r a g e ( m il li o n c u .m ) yield =55 % behavior gould jan feb mar apr may jun jul aug sep oct nov dec starting month 1000 2000 3000 4000 5000 6000 7000 8000 s to r a g e ( m il li o n c u .m ) yield =75 % behavior gould jan feb mar apr may jun jul aug sep oct nov dec starting month 240 260 280 300 320 340 360 380 400 420 v u ln e r a b il it y ( m il li o n c u .m ) yield=75% yield=55% jan feb mar apr may jun jul aug sep oct nov dec starting month 8.0 8.5 9.0 9.5 10.0 10.5 11.0 r r si li e n c e ( m o n th ) yield=75% yield=55% jan feb mar apr may jun jul aug sep oct nov dec starting month 1000 1500 2000 2500 3000 3500 4000 s to r a g e ( m il li o n c u .m ) yield =55 % behavior gould jan feb mar apr may jun jul aug sep oct nov dec starting month 10000 20000 30000 40000 50000 60000 s to r a g e ( m il li o n c u .m ) yield =75 % behavior gould figure 16:effect of starting month on storage estimates using generated data. figure 15:effect of starting month on vulnerability and resilience estimates using historical data. figure 14:effect of starting month on storage estimates using historical data. al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 032 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 length of generated sequence (year) 0 1000 2000 3000 4000 5000 6000 7000 8000 s to r a g e ( m il li o n c u . m ) tf-log ttm mttm fm 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 length of generated sequence (year) 800 1600 2400 3200 4000 4800 5600 6400 s to r a g e ( m il li o n c u . m ) tf-log ttm mttm trm figure 17:effect of inflow sequence length on storage estimates by behavior analysis (yield=75% of mean monthly flow). figure 18:effect of inflow sequence length on storage estimates by gould’s procedure analysis (yield=75% of mean monthly flow). al-qadisiya journal for engineering sciences ,vol. 6.no 3 year 2013 032 50 55 60 65 70 75 80 85 90 yield (%) 0 2000 4000 6000 8000 10000 s to r a g e ( m il li o n c u .m ) a. using historical data initially full initially empty 50 55 60 65 70 75 80 85 90 yield (%) 0 1000 2000 3000 4000 5000 6000 7000 s to r a g e ( m il li o n c u .m ) b. using generated data (tf-log) initially full initially empty 50 55 60 65 70 75 80 85 90 yield (%) 2000 4000 6000 8000 10000 12000 14000 16000 s to r a g e ( m il li o n c u .m ) c. using generated data (ttm) initially full initially empty 50 55 60 65 70 75 80 85 90 yield (%) 0 4000 8000 12000 16000 20000 24000 s to r a g e ( m il li o n c u .m ) d. using generated data (m ttm ) initially full initially empty 50 55 60 65 70 75 80 85 90 yield (%) 2000 4000 6000 8000 10000 12000 14000 s to r a g e ( m il li o n c u .m ) e. using generated data (frm) initially full initially empty figure 19:effect of initial conditions on storage estimates using behaviour analysis. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 211 addition of conductive screws to improve the mechanical properties of concrete khamail abdul-mahdi mosheer department of civil engineering al-qadisiyah university kh20072011@gmail.com received 22 december 2014 accepted 25 may 2015 abstract in the present paper, experimental investigations were conducted to improve the properties of concrete by using conductive screws as a fibre. screws of two different lengths were used (1/2 inch and 1 inch). these screws were made of iron coated with zinc-aluminium alloy (called al-clad), which is resistant to corrosion and rust. this coating gives the screw strength and flexibility. the water/cement ratio used was w/c = 0.55 and the volume fractions of the conductive screw were 0%, 0.5%, 1%, and 1.5% by volume of concrete mix. the results show that the use of the conductive screw enhanced the mechanical properties of concrete. the compressive strength increases with increasing the volume fraction of the screw with a length of 1 inch. for 1.5% fibre content, the strength was increased by 24.28%, 23.66%, and 20.91% for 7, 28, and 90 curing days respectively compared to the reference mix. the same trend was observed with the modulus of rupture results. for the same length and with the 1.5% volume fraction of fibre, the modulus of rupture increased by 19.44% and 32.26% for 7 and 28 days of curing respectively. the splitting tensile strength also increased by 27.05% and 33.17% for 7 and 28 curing days respectively for 1.0% fibre content. keywords: fibres, conductive screw, compressive strength, modulus of rupture, splitting tensile strength. الموصلة لتحسين الخواص الميكانيكية للخرسانةإضافة الصواميل خمائل عبد المهدي مشير جامعة القادسيةقسم الهندسة المدنية/كلية الهندسة/ الخالصة تم استخدام نوعين من .ألياففي البحث الحالي تم اجراء تحريات عملية لتحسين خواص الخرسانة باستخدام الصواميل الموصلة ك لصواميل الموصلة مصنوعة من الحديد انج(. هذه ا -1انج( اما النوع االخر بطول ) 5.0الصواميل الموصلة, النوع االول بطول ) سمنت التي الى والصدأ والتي تعطي القوة والمرونة للصواميل. نسبة الماء للتآكلالمنيوم والمسماة الكالد المقاومة -المطلي بسبيكة زنك and 1.5% ,%1 ,%0.5 ,%0( والنسبة الحجمية للصواميل الموصلة التي اضيفت للخرسانة كانت )w/c=0.55استخدمت كانت ) ان مقاومة االنضغاط قد الخواص الميكانيكية للخرسانة تحسنت بوجود الصواميل حيث ان لنتائج بينتا (.ةيالخرسان الخلطة من حجم ( يوم انضاج 8,95,,0ولألعمار )( 24.28,%23.66,%20.91)وصوال الى انج( -1اضافة الصواميل )طول ازدادت بزيادة نسبة mailto:kh20072011@gmail.com al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 212 وصوال انج( -1اضافة الصواميل )طول , كذلك زاد معامل الكسر للخرسانة بزيادة نسبة %1.0اضافة ولنسبة على التوالي الشد كانت مقاومة لاعلى نسبة زيادة , بينما %1.0يوم انضاج على التوالي ولنسبة اضافة 8,و0%( لعمر3,.,6% و 19.44)الى .انج -1للصواميل ذات طول %1.5اضافة يوم انضاج على التوالي ولنسبة 8,و0لعمر (%66.10, 0.50%,) 1 introduction cracks can form in concrete as a result of several factors, such as structural, environmental or economic reasons. the reason for cracks forming is that concrete shrinks when it is restrained. most cracks are formed due to the inherent weakness of the material to tensile forces. using fibres to reinforce concrete offers a solution for this problem by making concrete tougher and more ductile. the fibre works to delay the growth of cracks and allows smaller cracks to form instead, after the application of load on the member, thus increasing the tensile strength. this leads to the possibility of fibre-reinforced concrete to deform larger, beyond-the-peak stress, compared to conventional concrete (figure 1) (neville and brooks 2010). fibres made from materials such as steel, glass, synthetic materials and natural products help to improve various properties of concrete (irine 2014). a significant number of researchers have proved that the addition of steel fibres to conventional plain or reinforced and pre-stressed concrete members led to the enhancement of several properties of concrete, particularly those related to strength, performance and durability. the effect of using steel fibres on the behaviour of concrete has been studied by many researchers. the results obtained by aoude (2008) showed that the addition of steel fibres to concrete results in several enhancements, including the improvement of the tensile resistance, post-cracking strength, and toughness, as well as improving post-peak strength and ductility. in structural members, concrete reinforced with fibres has better shear resistance than conventional concrete; this enhancement in shear resistance is due to the improvements in the diagonal tension capacity of the concrete. steel fibres can be used to replace traditional shear reinforcement and promote flexural failure and ductility if added in sufficient quantity (cohen 2012). in columns, the addition of steel fibres enhances confinement and cover spalling (aoude et al. 2009). research has also shown that steel fibres can improve energy dissipation capacity at joints and shear walls (parramontesinos 2005). numerous factors influence the properties of fibre-reinforced concrete, such as the type, shape and amount of fibres used. a convenient parameter to describe a fibre is its aspect ratio (l/d), defined as the fibre length divided by an equivalent fibre diameter (wafa 1990). steel fibre is expensive in the local area market, as well as being difficult to obtain. using conductive screws made from iron coated with zinc-aluminium alloy (called al-clad), which is resistant to corrosion and rust, instead of conventional steel fibre will reduce the cost of concrete. in this study, conductive screws were used as a short fibre to reinforce conventional concrete. the screws were used in different volume fractions and lengths. experimental investigations were conducted to study the effect of this type of fibre on the fundamental mechanical properties of concrete. 2 experimental program the experimental program was designed to understand the behaviour of concrete reinforced with conductive screws in different volume fractions and lengths. the compressive strength, modulus of rupture, and tensile strength of the concrete mixers were investigated at different ages. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 213 2.1 materials used 2.1.1 cement sulphate-resistant portland cement (type v) was used, in line with iraqi standard specifications (no.5/1984). the physical and chemical properties of the cement used are given in table 1. 2.1.2 fine aggregate local river sand was used as a fine aggregate. natural sand from the al najaf sea region was used. grading and some physical properties of the sand are given in table 2. its grading conformed to the iraqi specifications (iqs) (no. 45/1984) zone 2. 2.1.3 coarse aggregate the coarse aggregate used complies with iqs no.45/1984. table 3 shows the grading and some physical properties of the coarse aggregate. 2.1.4 fibres conductive screws were used throughout the experimental program, as shown in figure 2-a. these screws were made from iron coated with zinc-aluminium alloy, which is resistant to corrosion and rust. the conductive screws were used in two different lengths: 0.5 inch and 1 inch, as shown in figures 2-b and 2-c. the screws used have a density of 7500 kg/m 3 and a modulus of elasticity of 200 gpa. some properties of the screws are listed in table 4. 2.2 mix proportions a water/cement ratio (w/c) = 0.55 and a volumetric mixing ratio of (1: 2: 4) (cement: sand: gravel) were considered necessary to give the concrete mix the required workability, with a specific slump (812 cm) for concrete reinforced with conductive screws. the fibres were added in volume fractions of 0%, 0.5%, 1%, and 1.5% by volume of the total mix for each test . the mix with no fibre was considered as a reference mix. 3 testing of concrete 3.1 compressive strength test the compressive strength test was conducted according to the standard specifications bs en 123903:2002. the program consisted of casting and testing a total of 72 cubic specimens of 150 x 150 x 150 mm. the volume fractions of the conductive screws added to the concrete were 0%, 0.5%, 1%, and 1.5% by volume of the total mix for each length of screw and for three curing ages (7, 28, and 90 days). the average of the compressive strength results of three cubes was recorded for each testing age. 3.2 flexural strength test a total of 18 concrete prisms of 100×100×500 mm were cast during this study. the test was carried out using the two-point load method according to astm c78-02. the volume fractions of the fibre (conductive screw) were 0%, 1%, and 1.5% by volume of concrete mix for length of 1.0 inch only and for the ages of 7 and 28 days. 0.5% of fibre was not considered as it is very small compared to the size of the concrete prism. the average of three prisms was recorded for each testing age. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 214 3.3 splitting tensile strength the splitting tensile strength was determined according to astm c496-04. a total number of 18 cylinders (100 × 200 mm) were cast and tested. the volume fractions of the fibre were 0%, 1%, and 1.5% by volume of concrete for the length of 1.0 inch only. the average of the splitting tensile strength results of three cylinders was recorded for each testing age (7 and 28 days). 4 discussion of the results 4.1 compressive strength and density the results of the compression test are summarised in tables 5 9 and plotted in figures 3 6. from the test results, it can be seen that the compressive strength increases gradually with increasing the fibre content for three curing ages (7, 28, and 90 days). the increase in compressive strength appears more clearly with fibre contents of 1.0 and 1.5% compared to the reference mix. for 1.5% fibre content (1-inch long screws), the compressive strength increased by 24.28%, 23.66%, and 20.91% for 7, 28, and 90 curing days respectively. for the fibre-length (1inch), the increase in compressive strength was more than that of the fibre length of 0.5 inch. from figure 7 it can be observed that there is a reduction in the width of the cracks and an increase in the number of cracks (under the influence of compressive stresses) with increasing the volume fraction of the fibre compared to the reference mix with zero fibre content. most of these cracks were inclined at different angles from the direction of loading. this is attributed to the fact that the load path is intercepted by the conductive screw, which leads to a change in its direction. the increase in the density of the concrete containing conductive screws is small, therefore the concrete remained within the limits of normal concrete weight (as shown in table 11). even though the density of these screws is greater than the density of concrete, the quantity of screws compared with the amount of concrete makes the effect of these screws on the density negligible. 4.2 flexural strength (modulus of rupture) the results of the flexural strength test shown in tables 10 and 11 and figures 8 and 9 show that the modulus of rupture of concrete increases with increasing the fibre content for all curing ages. for 1.5% fibre content, the modulus of rupture increased by 19.44% and 32.26% for 7 and 28 curing days respectively compared to the reference mix. this can be attributed to the fact that the fibre will enable the concrete to resist the tensile stresses. from figure 10-a for the reference mix prism, it can be noted that the width of the crack is large, singular and extends in a straight line from the top to the bottom. in this case, the failure was sudden. the conductive screw-reinforced concrete prism was more ductile. the crack is not straight and it tends towards the middle of the prism, which suggests that the screw intercepts the path of the crack, resulting in a small crack accompanied by other small cracks. the prism in the latter case will fail gradually (figure 10-b). 4.3 tensile strength the tensile strength test results are illustrated in tables 12 and 13 and figures 11-12. generally, the tensile strength increased in the concrete containing conductive screws as expected. for 1% fibre content (1-inch length), the splitting tensile strength increased by 27.05% and 33.17% for 7 and 28 curing days respectively. the strength begins to decrease at a ratio of 1.5%; however, this is still higher than that of the reference mix cylinders. this indicates that the optimum percentage of this type of fibre is 1% for this type of concrete. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 215 the benefit obtained from adding conductive screws is the reduction in the width of cracks in the concrete cylinder. the cracks are not extended throughout the length of the cylinder; instead, multiple cracks with inclined angles were observed (figure 13). 5 conclusions after analysing the results of the investigations, the following conclusions can be drawn: 1. the use of conductive screws works to improve the mechanical properties of concrete by increasing the compressive strength, flexural strength, and splitting tensile strength. this is due to the ability of this type of fibre to control and redistribute the stresses after cracking. 2. the increase in the mechanical properties of concrete when using 1-inch screws is greater than when using 0.5-inch screws. 3. the compressive strength, splitting tensile strength, and modulus of rupture of concrete increased with increasing the slenderness ratio of the screw (l/d). 4. the strength of concrete increased with increasing the fibre content. 5. the width of the cracks formed in the concrete decreased with increasing the fibre content; instead, there was an increase in the number of cracks. 6. the concrete remained within the limits of the normal weight of concrete. references [1] aoude, h. (2008), “structural behaviour of steel fiber reinforced concrete members.” phd thesis, department of civil engineering and applied mechanics, mcgill university, montreal, canada. [2] aoude, h., hosinieh, m., cook, w., and mitchell, d. (2014), "behavior of rectangular columns constructed with scc and steel fibers." journal of structural engineering, 10.1061/(asce)st.1943541x.0001165 , 04014191. [3] astm c496, (2004), standard test method for splitting tensile strength of cylindrical concrete specimen. american society of testing materials, west conshohocken. [4] astm c78, (2002), standard test method for flextural strength of concrete specimen. american society of testing materials, west conshohocken. [5] bs en 12390-3, (2002) ,testing hardened concrete part 3: compressive strength of test specimens, british standard. . [6] cohen, m. (2012), “structural behaviour of self consolidating steel fiber reinforced concrete beams,” m.s. thesis, dept. civil. eng., ottawa. univ., ottawa. [7] elsaigh, w.a. (2001), "steel fiber reinforced concrete ground slabs", msc. thesis, department of civil and biosystems engineering university of pretoria, pretoria. . [8] iraqi specification, no.45. (1984), “aggregate from natural sources for concrete and construction”. [9] iraqi specification, no.5. (1984), “portland cement”. http://ascelibrary.org/doi/abs/10.1061/%28asce%29st.1943-541x.0001165 http://ascelibrary.org/doi/abs/10.1061/%28asce%29st.1943-541x.0001165 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 216 [10] irine, f., (2014), "strength aspects of basalt fiber reinforced concrete", international journal of innovative research in advanced engineering, 1 (8), 192-198. [11] nevill, a.m. and brooks, j.j, 2010, "concrete technology", 2 nd edition, pearson education limited, england, 442 . [12] parra-montesinos, g. j. (2006), “shear strength of beams with deformed steel fibers”, journal of american concrete institute, 28 (11), 57-66. [13] wafa, f. f. (1990), “properties & applications of fiber reinforced concrete”. engineering sciences, 2(1), 49-63. [14] zhang, j.a., stang, h.b., and lia, v.c., (1999), "fatigue life prediction of fiber reinforced under flexural load" international journal of fatigue 21 (9), 1033–1049 . oxide composition oxide content % limits of iqs (5-1984) sio2 22.5 ____ al2o3 4.2 ____ fe2o3 5.7 ____ cao 63.1 ____ mgo 1.3  5.0 so3 2.41  2.5 free cao 1.5 ____ l.o.i 1.6  4.0 i.r 0.4  1.5 l.s.f 0.84 0.66-1.02 the main components (using bogue’s formulae) c3s 39.6 ____ c2s 27.8 ____ c3a 1.3 c4af 17.3 ____ physical properties fineness (blaine) cm2/gm 367 ≥250 initial setting time (vicat) (min) 120 ≥ 45 final setting time (vicat) (hrs:min) 3:40  10 soundness (autoclave method) % 0.02  0.8 table (1): properties of the sulphate resistance portland cement ( type v) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 217 sieve size (mm) passing % i.q.s.45:1984 limits ( 04-5 ) 00 155 155 36 155 60.0 155 155-90 ,5 04.06 05-60 14 8.36 15 16.0 45-15 0 5.54 05 sulphate content ( so3 ) = 0.0457 % (iraqi specification requirement ≤ 0.09%) fibre type average diameter (mm) head diameter (mm) length (mm) 1 3 7 12.7 (0.5 inch) 2 3 6.5 25.4 (1 inch) sieve size (mm) passing % i.q.s.45:1984 limits zone (2) 15 100 100 4.75 97.6 100-90 2.36 81.33 100-75 1.18 63.66 90-55 0.6 47.19 59-35 0.25 16.27 30-8 0.15 7.81 10-0 fineness modulus = 2.9 sulphate content ( so3 ) = 0.24 % (iraqi specification requirement ≤ 0.5%) table (2): grading and physical properties of the sand table (3): grading and physical properties of the coarse aggregate table (4): geometrical properties of conductive screws al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 218 fibre content % compressive strength (mpa) 7 days 28 days 90 days 0.0 14.00 19.15 21.35 0.5 14.94 ,1.96 24.56 1.0 10.04 2,.10 24.65 1.5 17.09 ,,.00 25.50 curing age (day) increase rate for compressive strength with reference mix % 0.5 1.0 1.5 7 1.15 5.21 19.09 28 14.51 15.40 17.49 90 13.30 13.85 15. 05 fibre content % compressive strength (mpa) 7 days 28 days 90 days 0.0 14.67 18.97 21.47 0.5 10.16 19.22 22.52 1.0 13.10 21.73 24.63 1.5 17.86 23.46 25.96 table (5): compressive strength and the fibre content relationship at different ages of the screw (for length 0.5 inch) table (7): compressive strength and the fibre content relationship at different ages of the screw (for length 1 inch) table (6): compressive strength increase rate and the fibre content relationship at different ages of the screw (for length 0.5 inch) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 219 curing age (day) increase rate for compressive strength with reference mix % 0.5 1.0 1.5 7 5.28 12.38 24.28 28 1.32 14.54 23.66 90 4.89 14.72 20. 91 fibre content % density (0.5 inch) ( kg/m 3 ) increase rate of density (for length 0.5 inch) % % density (1 inch) ( kg/m 3 ) increase rate of density (length-1 inch) % 0.0 2516.0 0.00 ,40,.3 0.00 0.5 2542.2 1.04 2486.3 0.55 1.0 2534.8 0.75 2488.2 0.63 1.5 2579.7 2.53 2493.8 0.86 table (10): the results of the modulus of rupture (screw length 1.0 inch) added percentage % modulus of rupture (mpa) 7 days 28 days 0.0 1.85 6.15 1.0 1.90 6.00 1.5 ,.10 4.15 table (11): the rate of change in the modulus of rupture when increasing the fibre content (screw length 1.0 inch) added percentage % change in modulus of rupture (7 days) % change in modulus of rupture (28 days) % 0.0 0 55. 0.00 1.0 +8.63 +14.0, 1.5 +19.44 +32.26 table (9): density versus fibre content table (8): compressive strength increase rate and the fibre content relationship at different ages of the screw (for length 1 inch) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 220 table (12): the results of the splitting tensile strength with different fibre content for ages o7 and 28 days fibre content % tensile strength (mpa) 7 days 28 days 0.0 2.05 2.44 1.0 2.73 3.10 1.5 2.60 2.95 table (13): the rate of change in the tensile strength with an increase in the fibre content (screw length 1.0 inch) fibre content % rate of change in tensile strength (7 days) % rate of change in tensile strength (28 days) % 0.0 0.00 0.00 1.0 27.05 33.17 1.5 20.90 +26.83 figure (1): typical stress deformation behaviour of fibre-reinforced concrete and unreinforced concrete (neville and brooks 2010) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 221 figure (2): (a) screws used, (b) length (1.0 inch), (c) length (0.5 inch) (b) (c) (a) screws used figure (3): the relationship between the compressive strength and fibre content (screw length 0.5 inch) figure (4): the relationship between the compressive strength and curing age (screw length 0.5 inch) 0.0 0.5 1.0 1.5 screw addition (0.5 inch length) 12 15 18 21 24 27 30 c o m p re s s iv e s tr e n g th ( m p a ) compressive strength 7 days 28 days 90 days 0 30 60 90 age (days) 12 15 18 21 24 27 30 c o m p re s s iv e s tr e n g th ( m p a ) compressive strength 0.0 % 0.5 % 1.0 % 1.5 % al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 222 figure (5): the relationship between the compressive strength and fibre content (screw length 1.0 inch) figure (6): the relationship between the compressive strength and curing age (screw length 1.0 inch) 0.00 0.50 1.00 1.50 %screw addition (length 1.0 inch) 12 15 18 21 24 27 30 c o m p re s s iv e s tr e n g th ( m p a ) compressive strength 7 days 28 days 90 days 0 30 60 90 age (days) 12 15 18 21 24 27 30 c o m p re s s iv e s tr e n g th ( m p a ) compressive strength 0.0 % 0.5 % 1.0 % 1.5 % (a) reference concrete cube (b) concrete cube with fibre figure (7): failure patterns of concrete cubes al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 223 figure (8): the relationship between the modulus of rupture and the fibre content (screw length 1.0 inch) 0.0 0.5 1.0 1.5 % screw addition 1.5 2.0 2.5 3.0 3.5 4.0 4.5 f le x tu ra l s tr e n g th ( m p a ) flextural strength 7 days 28 days figure (9): the relationship between the modulus of rupture and the curing age for different fibre contents (screw length 1.0 inch) 0 7 14 21 28 age (days) 1.0 2.0 3.0 4.0 5.0 f le x tu ra l s tr e n g th ( m p a ) flextural strength 0.0 % 1.0 % 1.5 % a) reference concrete prism b) concrete prism with fibre figure (10): failure patterns of concrete prisms al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 224 a) reference concrete b) concrete with fibre figure (13): failure patterns of concrete cylinders figure (11): the relationship between the splitting tensile strength and the fibre content (screw length 1.0 inch) 0.0 0.5 1.0 1.5 % screw addition 2.0 2.4 2.8 3.2 t e n s il e s tr e n g th ( m p a ) tensile strength 7 days 28 days figure (12): the relationship between the splitting tensile strength and the curing age with different fibre contents (screw length 1.0 inch) 0 7 14 21 28 age (days) 1.5 2.0 2.5 3.0 3.5 t e n s il e s tr e n g th ( m p a ) tensile strength 0.0 % 1.0 % 1.5 % al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 306 effect of turbulent prandtl number in the convective turbulent heat transfer modelling ahmed abed al-kadhem majhool mechanical engineering department, college of engineering, al-qadissiya university ahmidkadhim@yahoo.com received 1 september 2014 accepted 19 october 2014 abstract the aim of this work is to investigate the capability of the numerical predications for both dynamic and thermal fields in a turbulent flow by using eddy-viscosity turbulence model. a special case was chosen to predict forced convection heat transfer in low turbulent reynolds number and very low prandtl number fluids and investigate the sensitivity of these predictions to the type of the in-house code and to several input parameters. results obtained with a standard lrn (k-ε) turbulence model at relevant reynolds number for the fully developed turbulent channel flow (reτ = 180 and pr= 0.025), are presented and discussed. the mean velocity and temperature profiles agree very well with that of a reference direct numerical simulation (dns). keywords: turbulent prandtl number, turbulent heat flux, channel flow, turbulence modelling تاثير عدد براندال االضطرابي على نمذجة وسط انتقال حراري مضطرب الملخص ي في حيز مضطرب يعتمد على موديل لزوجة كي والحرارالتنبوء العددي لكال المجالين الحرالهدف من هذا البجث هو تحقيق امكانية النتقال حراري قسري باستخدام تيارات الحمل في وسط مضطرب عند الدوامة. الحالة الخاصة المختارة في هذا البحث هي التنبؤء ا بتغير في التنبؤات في برنامج صمم من قبل المؤلف متبوع هعدد رينولدز مضطرب قليل وعدد برندال قليل جدا وكذلك تحقيق هذ متغيرات االدخال. النتائج المستخلصة باستحدام موديل اضطراب يعتمد على نمذجة لزوجة الدوامة لعدد رينولدز منخفض لقناة في mailto:ahmidkadhim@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 307 معدل توزيع السرعة ودرجة قد اظهرت ونوقشت. ,(reτ = 180 and pr= 0.025)حالة اضطراب كامل في ظروف جريان بالمقارنة مع المصدر من المحاكة العددية المباشرة. الحرارة يظهر نتائج ممتازة 1. introduction the prandtl number is defined as the ratio between the viscous diffusion rate to the thermal diffusion rate and low prandtl numbers of fluids are fluids which have a prandtl number much lower than unity. in this case, the thermal diffusivity of the fluid is dominant. this property affects the boundary layer thickness of the thermal and the momentum boundary layer of moving fluids. for low prandtl number of fluid, the thermal boundary layer is much thicker than the momentum boundary layer. the transfer of heat in turbulent flow fields at low range of prandtl numbers can be affected by the turbulence for two reasons. firstly, the molecular diffusivity of fluid plays a more important direct role because it has the same order as the turbulent diffusivity. secondly, molecular motion causes thermal tags to escape from eddies and therefore reduces the effectiveness of the turbulence in mixing. a modified low reynolds number turbulence stress and heat flux equation model was developed by nishimura [1]. the low reynolds number turbulence model was implemented for numerical simulation of the turbulent-laminar transition. the old existing low reynolds number turbulence models generally require very thin mesh width between a wall and the first computational node to assure the accuracy in calculation. the modified version was based on a criterion for the distance between the wall and the first computational node, in which non-dimensional distance (y + ) must be less than 0.5. a sequence of direct numerical simulations (dnss) of turbulent heat transfer in a channel flow have been carried out by kawamura et al. [2] with different boundary conditions for velocity and temperature fields. in the velocity field, the turbulent poiseuille and couette flows were used; while in the temperature field, the uniform heat flux heating and the constant temperature difference were employed. they observed that the turbulent prandtl number is close to the unity in the near-wall region independent of the boundary conditions; whereas in the central region it depends mainly upon the conditions. therefore the turbulent prandtl number cannot be assumed to be a constant. direct numerical simulations study for the velocity and temperature fields for turbulent flow in a channel have been carried out by piller et al. [3] in order to examine the influence of prandtl number on turbulent transport. they recorded the influence of prandtl number on the eddy diffusivity and on statistical properties of the fluctuating temperature field. from their noticed that the ratio of the turbulent diffusivity at certain prandtl number al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 308 to the turbulent diffusivity at a prandtl number of unity is roughly constant over the whole crosssection of the channel. a numerical simulation of forced convection over a vertical backward-facing step was studied by otic et al. [4] which used a hybrid between large eddy simulation and direct numerical simulation methods, where the study for analyzing turbulent liquid metal flow. the numerical simulation was conducted at a reynolds number of 10,000 based on the step height and maximum mean inlet velocity, prandtl number of 0.006, and an expansion ratio of 1.20. the modeling convective turbulent heat transfer of a liquid metal was presented by bricteux et al. [5] with a prandtl number down to 0.01, which is the order of magnitude of lead-bismuth eutectic in a liquid metal reactor. they observed that the heat transfer for a low prandtl number fluid could be molecular even though the flow is turbulent, making the common reynolds analogy unsuitable. thermal fluctuations in a heated periodic channel have been modeled by monod et al. [6] by using large eddy simulation (les). the fluid prandtl number was chosen equal to 0.01 and the friction reynolds number to 395. they showed that, in low prandtl fluids, the characteristic scales of thermal fluctuations are much bigger than the dynamic ones. both isothermal and isoflux boundary conditions were considered in the work along with conjugate heat transfer boundary conditions. bricteux et al. [7] used different approaches for the numerical prediction of heat transfer in a turbulent channel flow at very low prandtl number and high reynolds number to compare among them. their investigations permitted to suggest that for the range of reynolds numbers envisaged the chien model can handle with to be the most proper one. they also showed that the correlation of kays allows to obtain reliable prediction of the temperature profile. in this paper, standard lrn (k-ε) turbulence model at relevant reynolds number for the fully developed turbulent channel flow for evaluating the turbulent prandtl number and fixed values are compared and their performance are assessed against dns data. 2. mean flow equations the governing equations for fluid motion are the navier-stokes equations. the flow is assumed to be a steady, turbulent and incompressible flow. when the density of a viscous fluid is constant, the equations are sufficient to model the flow in general form can be described in terms of the conservation of mass, momentum and energy equations, which can be written, in cartesian coordinates as: al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 309 where the total derivative is defined as: and where the over line symbol represents the mean quantity while the lowercase letters correspond to the fluctuating component of that quantity . where μ and σt are the fluid viscosity and turbulent prandtl number respectively. 3. constant wall heat flux model in fully developed heat transfer, the mean temperature is varying linearly which is increased as a function of, x, and the increased rate of heat transfer of increase can be determined by applying an energy balance to a differential element of the channel. in this case, the constant wall heat flux, qw, as shown in figure 1 is used which the given condition yields al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 310 where is the heat flux applied at the upper and bottom walls, k is the thermal conductivity, cp is the specific heat and is the bulk mean velocity. the right hand side of equation (8) is not constant, due to the presence of bulk velocity and the varying distance along the computational domain. by using the definition of prandtl number, pr =ν/α, the averaged energy balance equation becomes the above equation contains two unknown terms. the first term is the functions of mean temperature and the second term is turbulent heat flux. these are the quantities of primary interest. 4. the proposed turbulence model in this section, the eddy-viscosity models used in this study will be presented. the standard (k-ε) model of launder and spalding [9] is a two equation model requires two transport equations, one for k (the turbulent kinetic energy) and the other for (its turbulent dissipation rate) ǫ, to describe the turbulence. the low-reynolds-number (kε) model of launder and sharma [8] contains certain modifications which have to be made if one wants to apply this model to near wall regions, where the reynolds number is low. therefore the k and ε equations are thus: where pk, is the production term created by mean shear, defined as : 1the first modification is the presence of damping functions in order to account for the near-wall region and it is done through introducing a viscous damping function, fµ, into the turbulent viscosity equation. therefore, al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 311 the function fµ is used to account for both the true viscous damping at low reynolds number and then decreases across the viscous sub-layer and the preferential damping of the wall-normal fluctuations as the wall is approached. in this work, the damping function fµ is given by: where the turbulent reynolds number is defined as: 2the second modification is that the ε equation is solved for , where the latter represents the isotropic part of the turbulent eddy dissipation rate, therefore it can be defined as : 3the third modification is to introduce and add a new source term, this term accounts for extra dissipation near the wall in order to modify the turbulent kinetic energy prediction in this region where velocity gradients are changing rapidly. the new source term is commonly known as e-term, which is defined as: 5. case studied the standard test case of a flow field within a two dimensional, steady state, incompressible turbulent flow is used to validate the solver. the problem of the physical case of interest in this study is the developed turbulent flow of a low prandtl number fluid subjected to a uniformly heat flux in a channel. the case studied here is that of fully-developed flow through a plane channel of half-width (h) with a al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 312 wall of non-zero thickness (d) uniformly heated at its outer surface (as shown schematically in figure 2). the initial values which are used in the present work are listed in table 1. 6. numerical treatment the one dimensional finite-volume method (fvm) is used to discretize the governing equations on structured grids. the navier stokes equations are solving using simp le algorithm of patankar and spalding [10]. to discretize the governing equations for fluid flow, the cell-centered finite volume method is selected. in this algorithm the overall solution procedure is iterative and is based on a pressure-correction equation is derived from the discretized equations for continuity, momentum, energy, turbulent kinetic energy and turbulent dissipation rate. all simulated cases are carried out using non-uniform, with 210 nodes in the fluid region with an expansion ratio of 1.025. it is worth mentioning that in order to fix the reynolds number the height of the half-channel is taken to be 0.5 m. in the context of turbulent heat transfer, the boundary condition of isoflux where the wall is imposed to a constant heat flux. the iterative method which is implemented in the in-house code to solve the discretized equations is known as tri-diagonal matrix algorithm (tdma). 7. results and discussions the mean velocity profile is presented as a function of y+ in figure 3 and compared with the numerical direct numerical simulation (dns) data of a low reynolds number flow by kawamura et al. [2]for plane channel flow at reτ = 180. the present result is in good agreement with the numerical data. by taking dns data of [2] as a reference, the discrepancy of 6.5% on the bulk velocity is calculated which the present result is in good agreement with the numerical data. it is found a slight deviation from the reference data in the logarithmic region. this is due to a characteristic difference between the channel and the boundary layer flows. the logarithmic region can be found even in the case of the lowest reynolds number. in this work the effect of turbulent prandtl number cannot be affected on the mean velocity distribution. therefore, it can be shown from the figure that one curve is present versus the dns data. in the near-wall region, the model has the accurate asymptotic behavior and it is expected that the proposed model is applicable in turbulent channel flows. the dimensionless temperature profile al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 313 where tw, is the wall temperature and normalized by the friction temperature is displayed in figure 4a for various turbulent prandtl numbers. the profile is obtained at low prandtl number of (0.025) which matches very well to that of the dns of kawamura et al. [2], which validates the numerical methods. in order to figure out the obtainable results the figure has been magnified as reported figure 4b, only in a certain place to investigate the effect of turbulent prandtl number. there is no remarkable discrepancy of mean temperature exist for all fixed turbulent prandtl numbers [0.6,0.9,1.8,2and 4] except when the turbulent prandtl number is variable in the linear thermal regime. this is due to the law (t + = pr∗ y+). consequently, the variable turbulent prandtl number is set in the code as defined in the literatures in the form of, prt = νt/αt. it can be observed that in the thermal loglaw that below of prt = 1.8 the predicted profiles are underestimated the temperature over the channel height compared with the dns data. in the case of variable prt the overestimation of the turbulent heat diffusivity αt due to inaccurate modelling for this parameter because the large thermal diffusion which is caused by the much larger turbulent intensity in the central region. figure 5 shows the local temperature distribution along the computational domain by choosing a fixed five cases and one case variable turbulent prandtl number. from the results and since the momentum and thermal spectrum are not similar in the case of low prandtl number fluids, it can be concluded that changes throughout the flow field, with the largest changes occurring close to the wall. going farther, to investigate the effect of turbulent prandtl number on the heated turbulent behavior, the turbulent heat flux results from the combination of temperature and velocity fields. thus it is also important to recognize the convergence nature of velocity fields which in turns affects the convergence of turbulent heat fluxes. figure 6 shows the distribution of turbulent heat flux normalized by the friction velocity and temperature for six different turbulent prandtl numbers compared with dns data. from this comparison, it is clear that the peak of the turbulent heat flux decreases with the increase of turbulent prandtl number and moves towards the wall as the conductive sub-layer becomes thinner. in addition the most suitable value is when prt= 0.9 which leads to the effect of turbulent has the larger effect than the thermal field. the efficiency of the heat transfer from the heated solid wall to the fluid flow is described by the nusselt number. for constant wall heat flux boundary conditions the nusselt number is computed as al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 314 for more assessment to the above predictions and investigation figure 7a shows the variation of nusselt number at different turbulent prandtl numbers. all simulated cases show the same trend because the large thermal diffusion is caused by the much larger turbulent intensity in the central region of the channel flow. by using the same way the figure 7a is enlarged to show the overestimated results for turbulent prandtl numbers less than 1.8. finally figure 8 shows variation of the turbulent prandtl number along the channel height. the investigation will be only to justify the variable turbulent prandtl number. in the near wall region, is close to the molecular prandtl number value which is almost independent of both the thermal and velocity boundary conditions. in the central region, however, depends appreciably on the thermal and turbulent velocity fields and offers very low values approximately equal to 0.345. 8. conclusions despite obtaining fairly promoted results during the course of the case studied on the topic of fully developed turbulent channel flow with heat transfer, further work on this topic can be done in order to obtain better results for turbulent heat flux which is in more agreement with the available dns data. a fixed and variable values of turbulent prandtl number is used in the present work, but studies have shown that these constant values are have under predicted results across the channel and the variable case has an over predicted results. this could introduce inaccuracy in the present results and an alternative method should be found to model this. from this work, it might be conclude that the turbulence model needs to handle with the thermal eddy viscosity term. since it was taken to be constant in this work. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 315 9. references [1] m. nishimura. development of a low reynolds number turbulence stress and heat flux equation model. 7th international conference on nuclear engineering, tokyo, japan, april 19-23, 1999. [2] h. kawamura, h. abe and k. shingai. dns of turbulence and heat transport in a channel flow with different reynolds and prandtl numbers and boundary conditions. proceedings of 3rd international symposium turbulence, heat and mass transfer, editors y. nagano et al., 15–32, 2000. [3] m. piller, e. nobile and t. j. hanratty. dns study of turbulent transport at low prandtl numbers in a channel flow. journal of fluid mechanics. 458, 419–441, 2002. [4] i. otic , a. g. class and t. schulenberg. numerical investigation of turbulent low-prandtlnumber forced convection over a vertical backward-facing step. 7th international topical meeting on nuclear reactor thermal hydraulics, operation and safety seoul, korea, october 5-9, 2008. [5] l. bricteux , m. duponcheel and y. bartosiewicz. direct and large eddy simulation of turbulent heat transfer at very low prandtl number: application to lead-bismuth flows. proceedings of the international conference nuclear energy for new europe 2010, portoro, slovenia, sept.6-9, 2010. [6] r. monod , g. brillant , a. toutant and f. bataille. large eddy simulations of a turbulent periodic channel with conjugate heat transfer at low prandtl number. journal of physics: conference series 395, 2012. [7] l. bricteux, m. duponcheel, m. manconi and y. bartosiewicz. numerical prediction of turbulent heat transfer at low prandtl number. journal of physics: conference series 395, 012044, 2012. [8] b. e. launder and b. i. sharma. application of the energy-dissipation model of turbulence to the calculation of flow near a spinning disc. letters in heat and mass transfer, 1:131138, 1974. [9] b. e. launder and d. b. spalding. mathematical models of turbulence, london academic press, 1972. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 316 [10] s.v. patankar. numerical heat transfer and fluid flow. hemisphere publishing corporation, taylor and francis group, new york, 1980. nomenclature cp specific heat capacity at constant pressure cµ constant in equation 13 cε1 constant in equation 12 cε2 constant in equation 12 d total derivative d thickness eε molecular effect in equation 12 fε damping function in equation 12 fµ damping function in equation 14 h convection coefficient h height of half channel k turbulence kinetic energy nu nusselt number p mean pressure pk production term of k qw wall heat flux pr prandtl number prt turbulent prandtl number re reynolds number reτ turbulent reynolds number t temperature t + dimensionless temperature uiθ turbulent heat flux vector u + dimensionless velocity ub bulk velocity x cartesian coordinates in stream-wise directions y cartesian coordinates in wall-normal directions al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 317 y + dimensionless distance from the wall greek symbols ε dissipation rate of the turbulence kinetic energy ε ~ homogenous part of ε µ dynamic viscosity µt turbulent dynamic viscosity ν kinematic viscosity νt turbulent kinematic viscosity σt turbulent prandtl number figure 1: schematic showing the constant wall heat flux. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 318 figure 2: geometry of plane channel flow with heated wall. figure 3: mean velocity distribution. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 319 (a) (b) figure 4: profiles of mean dimensionless temperature. figure 5: local temperature profile at several turbulent prandtl numbers. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 320 . figure 7: variation of nusselt number along the channel height. figure 6: turbulent heat flux with different turbulent prandtl numbers al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 321 figure 8: variation of turbulent prandtl number along the channel height. 3 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 effect of compacting pressure on microstructure,physical and mechanical properties of niti sma noora mohammed gased , haydar a.h. al-ethari , ali hubi haleem department of metallurgical engineering, college of materials engineering, babylon university, babylon, iraq received 27 december 2015 accepted 21 january 2016 abstract this study investigates the effect of different compacting pressures on microstructure ,physical and mechanical properties of niti shape memory alloys. the sample were prepared by powder metallurgy technique. the powder mixture containing 55wt% ni and 45wt% ti were mixed for 5hours,compacted at different pressures (400,600,800 and 900)mpa to cylindrical samples, and sintered in two stages. first heating the compacted samples at temperature of 500°c for 2 hours and at a temperature of 950°c for 6 hours under vacuum conditions (10 -4 torr ) . the xrd test shows that the sample compacted at 800 mpa are consisting of three phases (niti monoclinic phase ,niti cubic phase , ni3ti hexagonal phase ).from the results, it was found that compacting pressure has essential effect on; improvement of shape memory effect properties(1.30-5.60)%, increasing hardness(from80.4to137) and compressive strength(from127.43to431.04)mpa and decrease porosity percentage(from32to22)%. key words: sma, niti, nitinol, powder metallurgy, compacting pressure. ير ضغط الكبس على التركيب المجهري والخواص الميكانيكية والفيزيائية لسبيكة نيكل تأث تيتانيوم ذاكرة الشكل علي هوبي حليم.دحيدر عبد الحسن العذاري , .د , نورا دمحم كاصد الخالصة: تيتغةنيط -يبةنيبيغة لبغ يبة نيبغلالتركيغ المهرغرو لالاغطال الييئية يغة لالمعلغ يتضمن هذا العمل دراسة تـأثير ضغوط البغ , يتغغغغغغأل للغغغغغغين المبغغغغغغة ي غغغغغغن ذاكغغغغغغرل التغغغغغغبل ل تغغغغغغس تدضغغغغغغير العيوغغغغغغةس حةسغغغغغغتا ا ري غغغغغغة تبوطلط يغغغغغغة المبغغغغغغة ي 45wt.%ti+55wt.%ni) سغغغغةعةس ثغغغغس ك بغغغغم حتبغغغغلين ضغغغغوط اتليغغغغة غغغغ ارهة 5(لللطغغغغم المبغغغغة ي امسةسغغغغية لمغغغغ ل (400,600,800 and 900mpa )طانية التبلل تمم عمليغة التل يغ حمغر لتين ,ألخ سغاوم ح ر غة غرارل لتتدطل ال نمةذج أسط في ط يرغ ن الرغطا سةعةس 6 در ة سيليئية للم ل 950در ة سيليئية لم ل سةعتين ل ن ثس استمرس ال در ة رارل 500 10لوةية ) -4 torr800ون المل ل لالمب طسة حض الومةذج حةن البيوية اخشعة يطد الت ةر (ل الضح mpa تدتطو عل ثالثة أ طار (ل ن لالل الوتة ج ل أن ضون الب يغثثر حتغبل ni3tiأضةفة ال طر niti ل طر المةرتوبةيم niti ) طر املستوةيم أسةسي عل تدبين لطال استعةدل الذاكرل لزيةدل الصالدل ل ةل ة اخنضوة لت ليل نب ة المبة يةل al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 1.introduction shape memory alloys (sma) possess different properties compared to conventional metals. this type of alloy is capable of remembering its shape following a deformation. relatively large recoverable strain of around 8% is one of the sma’s distinct properties, which makes it a favorable candidate for applications involving large deforming loads. nitinol (niti alloy) is one of the most well-known shape memory alloys. such alloy is composed of nickel and titanium in approximately equiatomic ratio [1]. nitinol is capable of displaying pseudoelasticity giving the material the ability to transform between phases upon loading and unloading and recover to its original zero strain shape after significant deformation. with the properties such as repeatability, wear resistance, corrosion resistance and biocompatibility, niti is the most commercially successful sma [2].the shape memory and pseudoelastic characteristics coupled with the biocompatibility of niti alloys make them an attractive candidate for medical applications such as cardiovascular and orthopedic applications[3].furthermore, several studies such as sadrnezhaad, et.al.[4] reported that commercially pure nickel-titanium powders were compacted and sintered at different temperatures for different times. amorphization and interatomic phase formation were determined by x-ray diffractometry, scanning electron microscopy and differential scanning calorimetry. porosity, virtual density, transition temperatures and the amount of ni3ti first increased and then decreased with the milling time. carlton g. slough, et.al. [5] studied the nitinol shape-memory alloy solid-solid transition using differential scanning calorimetry (dsc), which reveals the reversible and hysteretic nature of this transition. the results show that the dsc is an excellent technique for examining the solid-solid transition in nitinol shape-memory alloys. this transition is a first order transition that shows no dependency on heating rate. this research aims at investigating the effect of compacting pressure (400to900)mpa on mechanical properties of ni-ti shape memory alloys prepared by powder metallurgy. 2. experimental part in order to prepare samples of niti smas, powder metallurgy technique had been used. this method involves weighting the powders (55wt%ni with 45wt%ti) by using a sensitive balance device, mixing, compacting and then sintering them. the purity, average particle size and the original of ingredients used in this work are shown in table 1. wet mixing was carried out by the electrical rolling mixer apparatus to achieve a homogenous distribution of the powders. stainless steel balls with different diameters had been used during the mixing process to ensure refining and mixing the powders for a period of 5 hours. after mixing, all samples were compacted at 400,600,800 and 900 mpa. compacting was achieved on an electric hydraulic press machine. a steel die of 10 mm in diameter was used to prepare samples of 10mm in diameter and 5mm in height. following the compaction, all samples were sintered at two stages, the first at 500 °c for 2hrs and then heated at 950 °c for 6hrs (the samples were allowed to heat up with a heating rate of 10°c/min) using a vacuum furnace (gsl-1600x ). the pressure of the vacuum furnace was 10 -4 torr. 3. test 3.1. particle size measurement the particle size for ni and ti powders was tested by using laser particle size analyzer [model: better size 2000]. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 3.2. microstructure all surfaces of the samples including the edges were wet ground using 120, 220, 320, 600, 1000, 1200 and 2000, grit silicon carbide papers. etching solution consisting of [10% of hf, 20% of hno3 and 70% of h2o] at room temperature was used[6]. the samples was washed with distilled water and dried using electric drier. optical microscope and scanning electron microscope (sem) were used to capture the microstructure of the surface sample. 3.3. x-ray diffraction analysis x-ray diffraction method was used to define the phases of sintered samples and the green compact samples in order to compare these diffraction patterns with sintered diffraction patterns for the same samples. the x ray generator with cu at 40 kv and 30 ma was used. the xray is operating at a scanning speed of 7° (2ɵ) per minute. the detector was moved through an angle of 2ɵ = 20 to 80 degrees. 3.4. density and porosity measurement the green density of compacted samples was calculated as follows[7]: g g g v m  where : ρg: green density (g/cm 3 ) g m : green mass of the compacted sample(g); and g v = volume of the compact (cm 3 ). the ratio of pore volume to the total volume is called green porosity which can be determined from the following equation[7]: pg = (1ρg / ρth) × 100 (2) where pg green porosity percentage% ρg : green density of the green sample (g/cm 3 ) th: theoretical density of the bulk material (g/cm 3 ) . the theoretical density(ρth) can be calculated by the weight percentages of elemental powder multiplies by its theoretical density as follows[8] . nn n i tb wtwtwtwt  *...........*** 33 1 2211    … (3) where: ρ1,2,…,n: theoretical density of the elemental powder (g/cm 3 ) wt1,2,..,n : weight percentage (%)of elemental powder in the alloy. the density and porosity of sintered specimens are calculated basing on astm b-328 [9]following the procedure of: (1) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171  the specimen was dried at 100°c for 6 hour in vacuum furnace under a pressure of ((10 -4 torr) then cooled to room temperature, the weight of dry specimen was recorded as mass a.  at room temperature, the specimen was immersed in oil (with a density do = 0.8 g / cm 3 ) by using a suitable evacuating pump for 30 min.  weighing the fully impregnated specimen in air, the mass was recorded as b.  weighing the fully impregnated specimen in water (mass,f).  measuring the temperature and find the density of water at this temperature. for this study, the temperature was 30°c, at which the density of water (dw) at this temperature was 0.9956 g / cm 3 .the density (d) was computed according to the following equation: d=[(a/b-f)] dw (4) and the porosity was measured as: dw dfb ab p           100 )(  (5) 3.5. hardness test macro hardness brinells tester was used to measure the hardness of the sintered samples with 2.5mm ball diameter as indentation ball and (31.25n) as applied load .an average of three readings had been recorded in this test. 3.6. compression test the compression test was performed according to astm b925-08 specifications via universal testing machine type (wdw 200,china). standard sintered sample of (10mm diameter × 12mm height) were used .the test was achieved at constant loading speed of 0.1mm/min. 3.7. shape memory effect the shape memory effect was determined basing on brinell indentation as follows[10]: 100 %) (smeeffect memory shape    b ab d dd (6) where: b d = average impression diameter in (m) before heating to 80°c. a d = average impression diameter in (m) after heating to 80°c. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 4. results and discussion 4.1. particle size analysis particle size analysis results of ni and ti powders are shown in figures (1) and (2) respectively. it is clear that the average size of the powder was 12.06 µm for ti and 36.80µm for ni respectively. 4.2. green density and porosity of compacts the effect of compacting pressure on green density and green porosity of the prepared samples is shown in figure(3).as it is clear an increase in the compacting pressures resulted in an increase in the green density and degrease in the green porosity of the prepared samples. the maximum green density attained was 5.23 (g/cm 3 ), corresponding to a porosity level of 24.5% due to maximum compacting pressure of 900 mpa. increasing in pressure causes the elimination of more pores and creation of new contacts, and finally homogeneous deformation of the whole compact[11]. 4.3. density and porosity after sintering the effect of compacting pressure on the density of the sintered sample is shown in figure(4a).the results indicate that the density after sintering is increased with the compacting pressure. this increase is likely due to the shrinkage of original pores during sintering. figure(4b) shows the change of final porosity with compacting pressure. it is found that porosities are decreased after sintering, this reduction is attributed to the high temperature during sintering which led to reduce the size of pores in the structure and rejected the air from the pores. 4.4. x-ray diffraction analysis the xrd pattern of the green compact sample is shown in fig.(5). it can be seen that only ni and ti phases were detected because during compacting process, no phase transformation take place. figure (6) represents the chart of x-ray diffraction results after sintering process of the alloy sample prepared using a compacting pressure of 800 mpa. the full transforming of niti alloy to monoclinic niti phase ,cubic niti phase and hexagonal ni3ti phase can be easily observed. the suggested reactions during the process are as following [12]. ni + ti → niti ∆g: 67 kj / mol ni + ti → ni3ti ∆g: 140 kj / mol according to the phase diagram of niti system , niti and ni3ti are stable compounds, also reaction according to equ.2 is more thermodynamically favored than that represented by eq.1. consequently, it is difficult to remove the ni3ti from sintered sample only by altering the sintering condition[12,13]. 4.5. microstructure observation of the sintered samples figure(7) shows the microstructure of all sintered samples compacted at different pressures. the microstructure of these alloys showed pores with different size, present phase and grain boundaries. the pores are rarely interconnected and randomly distributed. it can be observed that with increasing compacting pressure from (400 to 900) mpa ,the pores become smaller, the pore number decrease and its distribution becomes more uniform. this is because when compacting pressure increased the pore tend to be compact and take around. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 all scanning electron microscope (sem) images of the etched samples with different compacting pressure are shown in figure(8), respectively. sem images are sensitive to chemical composition as result the microstructure of sintered samples showed two kindes of phases (niti and ni3ti ).the formation of martensite phase from disorder or ordered b2 (austenite) in the sintered sample is clearly. the martensite phase formed in all alloys have a needle shaped grains, because the diffusion less feature of martensite transformation. 4.6. hardness test figure (9) demonstrates the hardness of the specimens compacted at different pressures after the sintering process. the results indicate the increase in hardness of the specimens with increasing the compacting pressure. this agreed with the fact that as the compacting pressure is increased, the bonding between the particles is better (i.e. better inter diffusion) which in term leads to more pores elimination[14]. 4.7. compression test table (2) shows the values of compressive strength (σcom) ,are increased with increasing the compacting pressure because the total amount of porosity in the mass are decreased. the results are in agreement with ref.[10]. 4.8. shape memory effect the sme values as a function of compacting pressure (400,600,800 and 900mpa) for all prepared alloy samples are shown in figure(10). it is clear from this figure that the sme increased by the increasing of the compacting pressure due to the elimination of porosity. sme values for master alloys showed smaller values than the values of dense form which reach to 8-10 % [3]. 5. conclusions based on the results obtained in the present work, the conclusions can be summarized as follows: 1scanning electron microscope observation indicated that the most samples compacted at ( to ) m a and sintered at c for 2hrs and then heated at c for hrs ha e a c ear martensitic structure 2the increasing in compacting pressure from (400 to 900) mpa for master niti alloys resulted in an improvement in shape memory effect (sme) and hardness, increasing in density and decreasing in porosity. 3. compressive strength of niti sma alloys produced by pm increases with decreasing the porosity (increasing compacting pressure ). 6.references [1] z. karbaschi, " torsional behavior of nitinol: modeling and experimental evaluation" m.sc. thesis, university of toledo, 2012. [2] l tan and w c cron, ‟ in situ tem observation of two step martensitic transformation in aged niti shape memory alloy" script a material, vol. 50, 2004, pp. 819 – 823. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 177 [3] c. dimities and lagoudas, " shape memory alloys modeling and engineering application ", texas a&m university, usa, 2008. [4] s. k. sadrnezhaad and a. r. selahi, "effect of mechanical alloying and sintering on ni-ti powders", materials and manufacturing processes, vol.19, 2004, pp.475-486.45 [5] carlton g. slough," a study of the nitinol solid-solid transition by dsc", 2007. [6] afari, s e ar ad and s sa adi, effect of pre strain on microstructure of ni ti orthodontic arch wires , materials science and engineering a. 473 , 2008 , pp . 42 48. 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[12] s.l.zhu, x.j.yang, d.h.fu, l.y.zhang ,c.y.li and z.d.cui, "stress-strain behavior of porous niti alloys prepared by powder sintering" materials science and engineering a408,2005,pp.264268. [13] bing-yun li , li-jian rong , yi-yi li and v. e. gjunter ,"an investigation of the synthesis of ti50 at. pct ni alloys through combustion synthesis and conventional powder sintering", metallurgical and materials transactions a, vol..31a, issue 7,july 2000,pp.1867-1871. [14] sheelan r. areef, " characterization of ni-ti shape memory alloys", eng. & tech. journal, vol. 28, no.5 , 2010. table (1): powders used to prepare samples of niti alloy. materials purity % average particle size(μm) source titanium powder 99.75% 12.06 changxing galaxy international trade co.,ltd. nickel powder 99.65% 36.80 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 table (2): compressive strength for all samples compacted at different pressure. sample with different compacting pressure 400mpa 600mpa 800mpa 900mpa compressive strength (σ com)mpa 127.43 221.15 338.58 431.04 figure (1): particle size distribution of ti powder used in this study. figure (2): particle size distribution of ni powder used in this study. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 171 5 10 15 20 25 30 35 200 300 400 500 600 700 800 900 1000 compacting presssure (mpa) p o r o s it y % 5 10 15 20 25 30 35 40 200 300 400 500 600 700 800 900 1000 compacting pressure (mpa) g r e e n p o r o s it y % (a) (b) figure (3): effect of compacting pressure on:(a) green density of the prepared sample, (b) green porosity of the prepared sample. 2 3 4 5 6 200 300 400 500 600 700 800 900 1000 compacting pressure (mpa) d e n s it y a ft e r s in te r in g ( g /c m 3 ) (a) (b) figure (4): effect of compacting pressure on :(a) density of the sintered samples,(b) porosity of the sintered samples. 1 2 3 4 5 6 200 300 400 500 600 700 800 900 1000 compacting pressure(mpa) g r e e n d e n si ty (g /c m 3 ) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 111 figure (5): xrd pattern of the green compact sample. figure (6): xrd pattern of sample compacted at 800 pressure after sintering. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 111 figure (7): microstructure for alloys compacted at a: 400 mpa b: 600 mpa c: 800 mpa and d: 900 mpa respectively(400x). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 111 figure (8): sem images for etched alloys compacted at a: 400 mpa b: 600 mpa c: 800 mpa d: 900mpa. 0 20 40 60 80 100 120 140 160 200 300 400 500 600 700 800 900 1000 compacting pressure (mpa) h b figure (9): effect of compacting pressure on the hb values of the sintered alloy sample. 0 1 2 3 4 5 6 200 300 400 500 600 700 800 900 1000 compacting pre ssure (m pa) s m e % figure (10): effect of compacting pressure on sme properties obtained from brinell hardness test. article al-qadisiyah journal for engineering sciences 12 (2019) 025–030 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: eng.awwab.qasim@uobabylon.edu.iq (awwab q. jumaah) https://doi.org/10.30772/qjes.v12i1.583 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. a review and comprehensive study of wireless channel in mobile communication system: fading phenomena and estimation awwab q. jumaaha* auniversity of babylon, collage of engineering, department of electrical engineering, babil, iraq. a r t i c l e i n f o article history: received 03 february 2019 received in revised form 25 march 2019 accepted 28 march 2019 keywords: fading channels channel state information channel impulse response estimation techniques second order statistics a b s t r a c t in wireless communication systems, the channel estimation problem has been played an essential challenge to accurately retrieve the channel state information (csi) such that reliable communication & wide coverage can be provided. due to the improvement and rapid growth of communication systems and in order to maintain a reliable data transmission, estimation of csi has become necessary. this in turn results, precise receiver demodulation, accurate decoding, and equalization processes. this paper gives a survey on a fading phenomena and a comprehensive review of the recent works that have already been done and studied related to the problem of estimating channel parameters in wireless communication systems. varieties of best channel estimation techniques that have been recently evolved are explored. comparison between them in terms of computational cost, simplicity and appropriateness conditions is also discussed. this paper also provides a basic introduction of wireless channel model, simo and mimo channel. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction signals transmitted through a wireless communication channel exposed to a severe physical environment in a complicated manner. obstructions such as mountains, infrastructures, and trees produce signal diffractions, reflections and scattering. subsequently at the receiver end, received signals have falsifications, delays, interference and different phase shifts due to multipath signals generated. the term fading comes from devastatingly interfering multipath signals with each other. the fading might affect the quality and reliability of communication systems by causing decay in a power signal to noise ratio (snr), which may result in a communication failure. the phenomena of fading can be categorized into two basic kinds: small-scale fading and large-scale fading [1]. small-scale fading is also known as a rayleigh fading which comes from variations in phase and amplitude of transmitted signals since there are trivial spatial separation alterations among a transmitter and receiver. a rayleigh pdf (probability density function) can statistically describe the envelope of received signals when there is fading, no a line of sight, signal component presents whereas a rician pdf can describe a small fading envelope if there is no dominant fading present [1]. furthermore, over large areas, the path loss related to motion or attenuation in the average signal power corresponds to large-scale fading. a doppler shift is another characteristic of the wireless channel, and it is generated due to the fact that the wireless communication channel is time varying in nature or due to a movement http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 26 awwab q. jumaah /al-qadisiyah journal for engineering sciences 12 (2019) 025–030 between the transmitter and receiver [2]. the effect of multipath propagation is clearly seen as shown in fig. 1, while the transmitted signal arrives at the receiver as multipath signals. they reach at the receiver ends with a various doppler shift, phase shift, time delay and amplitude. figure 1: multipath propagation in mobile communication system channel state information (csi) has to be precisely provided at system receivers to get optimum performance for wireless communication systems and, therefore, transmitted signals can be detected in a coherent way. otherwise, a non-coherent method is the only way to demodulate transmitted signals such as the differential demodulation technique, result in a loss 3-4 db in snr [3]. many papers have been addressed the problem of channel estimation, and different estimation techniques have been developed to provide channel state information at the receiver ends so that a reduction in snr can be mitigated. this paper emphasizes reviewing some recent channel estimation techniques been investigated. the paper structure is as follows: wireless channel model is depicted in section 2, while section 3 presents a preview of works that have already been evolved regarding the issue of channel estimation methods. finally, section 4 gives some concluding remarks of the survey. 2. wireless channel model the wireless communication channel probably characterized by a vector called an impulse response that has most the information to analyze signals transmitted through channels. basically, the channel impulse response cir represents the instantaneous case of a dispersive channel due to different multipath components. resulting, vectors have variable instantaneous amplitudes [4]. let denote 𝑠(𝑡) to be the transmitted signal through a wireless communication, and𝑥(𝑡)to be the equivalent complex baseband form of 𝑠(𝑡), which can be described by a multipath fading as: 𝑠(𝑡) = 𝑅𝑒{𝑥(𝑡)𝑒𝑗𝜔𝑐𝑡 } (1) where 𝑅𝑒{∙} indicates the real part and 𝜔𝑐 is the carrier frequency that equals to 2𝜋𝑓𝑐 . now, the signal received is formed as: 𝑟(𝑡) = ∑ ℎ𝑙 (𝑡)𝑠(𝑡 − 𝜏𝑙 (𝑡)) 𝐿−1 𝑙=0 (2) where 𝐿 , 𝜏𝑙 (𝑡) and ℎ𝑙 (𝑡) are the number of paths, 𝑙 𝑡ℎ path time-variant delay and the complex time-variant amplitude, respectively. substitute equation (1) into equation (2), yields 𝑟(𝑡) = 𝑅𝑒{∑ ℎ𝑙 (𝑡)𝑒 −𝑗𝜔𝑐𝜏𝑙(𝑡)𝑥(𝑡 − 𝜏𝑙 (𝑡))𝑒 𝑗𝜔𝑐𝑡𝐿−1 𝑙=0 } (3) the received signal is assumed now contaminating by a complex additive gaussian noise 𝑛(𝑡) having zero means and equal variances. those parameters correspond to the parts (real and imaginary) of the noise. equation (4) shows a mathematical representation of the noise variance: 𝜎𝑛 2 = 𝑁0𝐵 = 𝔼{𝑛(𝑡)𝑛 ∗(𝑡)} (4) where 𝑁0 and 𝐵 are the power spectral density (w/hz) and effective bandwidth (hz) of the noise, respectively. the term 𝔼{∙} stands for expectation. equation (3) will be then rewritten after an additive white complex gaussian noise corrupts the received signal 𝑟(𝑡) as [5]: 𝑦(𝑡) = ∑ ℎ𝑙 (𝑡)𝑒 −𝑗𝜔𝑐𝜏𝑙(𝑡)𝑥(𝑡 − 𝜏𝑙 (𝑡)) + 𝑛(𝑡) 𝐿−1 𝑙=0 (5) let now define 𝑔(𝑡, 𝜏) to be the channel baseband impulse response at the time instant 𝑡 associated with the multipath fading. usually, the cir 𝑔(𝑡, 𝜏) utilized to model the mobile wireless channels is defined in equation (6). then the baseband signal 𝑦(𝑡)received specified in equation (5) can be rewritten again as in (7). 𝑔(𝑡, 𝜏) = ∑ ℎ𝑙 (𝑡)𝑒 −𝑗𝜔𝑐𝜏𝑙(𝑡)𝛿(𝜏 − 𝜏𝑙 (𝑡)) 𝐿−1 𝑙=0 (6) and 𝑦(𝑡) = ∫ 𝑔(𝑡, 𝜏)𝑥(𝑡 − 𝜏)𝑑𝜏 + 𝑛(𝑡) ∞ −∞ (7) where 𝛿 is the function of the dirac delta. for more simplicity, the linear time-invariant model is assumed to characterize the channel impulse response. this occurs when there is no variation in time 𝑡 in the second orderof the 𝑔(𝑡, 𝜏) statistics.at this point, a wireless channel considers to be a wide sense stationary (wss) process. the equation (6) is simplified based on the assumption mentioned to [6]: 𝑔(𝜏) = ∑ ℎ𝑙 𝑒 −𝑗𝜔𝑐𝜏𝑙 𝛿(𝜏 − 𝜏𝑙 ) 𝐿−1 𝑙=0 (8) details of the statistics, sample and non-sample spaced schemes for the cir can be found in [7, 8, 9 and 10]. 3. the methods of channel estimation signals transmitted via wireless communication are usually distorted: hence, information of any distortion should be necessarily provided using the channel estimation process. reliability of this process determines performance accuracy of the wireless system, and it can be then used for signal demodulation, decoding or equalization processes [11].this section presents a review of different channel estimation techniques efficiently developed. decision directed, pilot aided, semi-blind and blind are the essential solving techniques for the problem of channel estimation. overview for each class is illustrated in the following subsections. 3.1. channel estimation using decision directed techniques the estimation process of this technique employs training symbols along with the detected one. a model of channel estimator using decision directed awwab q. jumaah /al-qadisiyah journal for engineering sciences 12 (2019) 025–030 27 approach is illustrated in fig. 2 [12]. it is very important to look first on the term of a posteriori channel transfer function. its initial can be provided based on the obtainable detected symbols, and current received. in the next slot time and throughout the demodulation process of the next received symbols, this a posteriori channel transfer function estimated earlier utilized as an a priori channel estimate [13]. details of how a block diagram depicted in fig. 2 works can be found in [14]. figure 2: a model of channel estimator using decision directed technique [12] the important feature of this technique is requiring slight pilot symbols to initialize the process of channel estimation. in [15], akhtman, and hanzo proposed decision directed techniques for code division multiple access (cdma) having multi-carrier and ofdm systems, in which a channel is assumed to be a sample spaced model. in literature, this model is not fit for the real time scenario. however, a scenario of the non-sample spaced model for channel impulse response is assumed to execute the decision directed scheme presented by [16, 17] for ofdm systems using the recursive least square (rls) algorithm as an adaptive predictor [18]. however, the computational complexity is the major drawback when the subcarrier numbers of ofdm system are much more than the channel path numbers. consequently, munster and hanzoin [19] studied the performance of an adaptive ofdm transceiver that uses a modulation mode adaptation and decision directed methods. the multiple input-multiple output (mimo) ofdm systems restudied as in [20] in order to reduce the inter-antenna interference or inter-symbol interference (isi). here, it assumed the channels are independent, and the research effort is to exploit the estimated delay of the channels for estimating channel parameters. du and li in [21] exploited a subspace-based decision directed method for mimo ofdm system using an adaptive filter with low rank. however, at low snr, it is noted that the performance degrades since the strong noise causes subspace tracking error. there are two iterative schemes for decision directed channel estimation. a refined hard or soft symbol information determined by a decoder or a detector can be utilized by an estimator and fed it back to achieve high estimation accuracy as an increase in the number of iterations. the hard decision output of the decoder or detector can be used by the estimator if a hard symbol utilized. this is called hard iterative channel estimation. however, if the soft information symbols are employed, the channel estimator makes use of log-likelihood ratios (llr) on the coded bits determined by either the decoder or detector for channel estimation. this channel iterative scheme is referred to as a soft iterative channel estimation [22]. the hard and soft decision feedbacks taken from equalizer are presented in [23] for iterative channel estimation to improve parameters estimation while the authors in [24] proved that soft decision exhibits better performance than hard decision feedback. al‑susa and ormondroyd in [25] discussed a coherent ofdm system utilizing a predictor as a channel estimator in the existence of selective fading channel with the assumption of time-varying frequency. the research effort is exploiting an adaptive technique in a decision directed to make a decision at the output of either the decoder or detector. in [26], a joint iterative channel estimation technique is proposed to build a system receiver under the environment of fading channels by taking the advantage of turbo coding and power of assisted modulation symbols.however, an iterative channel estimation based on a new initial estimation approach of fading channel amplitudes is proposed in [27] as well as a new way of initializing a delayed turbo decoding is presented. implementation of the direct sequence ultrawideband is carried out in [28] that is based on the application of the coherent detection and iterative channel estimation. an improved in maximum likelihood (ml) channel estimator is presented by [29] using a decoder of soft input-soft output at the receiver and convolutional encoder at the transmitter. a channel estimator along with the turbo decoder makes an iterative detector that proposed for ofdm systems in [30].comparative outcomes are illustrated in [31] for soft feedback iterative decision directed technique with turbo codes as well as the channel error correcting coding which is low-density parity check codes. lastly, in [32], an iterative decision directed technique having lower complexity for channel estimation of mimo ofdm systems is presented whilst, in [33], a decision directed approach is proposed for ofdm systems with utilizing fractionally-spaced and sample-spaced channel impulse response estimators. 3.2. channel estimation using pilot assisted technique it is a classical approach for estimating wireless communication channels, and it is known as a training based. the transmitted symbols are multiplexed with the data of training sequences recognized to the receiver at a predetermined position prior transmission. at the receiver end, training symbols are employed to estimate the channel state information (csi) based on their positions [22]. in the literature, many research works have been published addressing the problem of channel estimation based on the pilot assisted technique. earlier, in [34], a comparison was done between superimposed pilot assisted modulation schemes, and pilot assisted modulation that was proposed by [35]. it was found that the pilot assisted modulation performs better in bit error rate (ber) than the superimposed pilot assisted modulation technique. however, the opposite results can be achieved in the fast fading channel whereas the tradeoff is high computational complexity. cai, and giannakis in [36] proposed a psam, which is an adaptive pilot symbol assisted modulation, for solving the problem of both prediction errors and channel estimation. the research effort was maximizing spectral efficiency by optimizing the spacing and power allocation between data symbols and pilots. it was claimed by the authors that, even feedback delay is large, the proposed technique performs well. in [37], the estimator based maximum likelihood (ml) is investigated for the ofdm system. in fast varying channels, the article in [38] proposed a pseudo pilot algorithm, which mainly depends on the approach of regression model based least squares fitting, for detecting data symbols without increasing the pilot density. moreover, the authors in [39] present a pilot pattern design and an optimal training for ofdm systems over a rayleigh fading channel. in [40], pilotassisted channel estimation is optimized for open loop ofdm systems. it is assumed optimal pilots have uniform spacing. further, to minimize feedback, lloyd algorithm and vector quantization together are used. in 28 awwab q. jumaah /al-qadisiyah journal for engineering sciences 12 (2019) 025–030 [41], a comparison between the bayesian minimum mean squared error (bmmse), which exploits a prior of informational statistics about the channel, and the ml estimators is done for ofdm systems. since ml estimator does not necessitate any of the channel informational statistics, its implantation is very simple. however, it exhibits performance degradation at low snr while bmmse exhibits better performance due to a prior of information statistics. they have comparable performance at high snr. finally, many research papers have been published with the system consideration of mimo regards to the technique of pilot assisted channel estimation. such contribution found in [42 and 43]. in [44], the authors presented a design of mimo ofdm systems with optimal training in the presence of phase noise and frequency offset. 3.3. channel estimation using semi-blind and blind techniques training symbols do not require in this technique, while the observed received signal, which is the only measureable signal, used for estimating channels by providing the transmitted signal properties and inherent information. the blind techniques can be classified into statistical approaches that utilize the cyclic properties of signals received and deterministic methods that assume or consider channel parameters and signals received having deterministic quantities [45]. in the literature, blind channel estimation using deterministic and statistical methods can be found in [46-48] for single antenna ofdm communication systems. the process of blind channel estimation is depicted in fig. 3. figure 3: simple block diagram of the process of blind channel estimation [49] the higher order statistics (hos) of received signals are what earlier blind methods depend on for estimate channel coefficients. such works found in [50-51]. a high computational complexity faces them since these methods require a long record of data samples or huge information. therefore, researchers relied on the second order cyclic statistics (sos) to invent and develop new blind methods as in [52 and 53]. in [54], the channel estimation based blind method is proposed in the frequency domain whereas, in [55], the single input-single output (siso) fir channel is blindly estimated by using sos of transformed data. necker and stuber in [56] studied deterministic blind approach based on the ml for phase shift keying signals. in ofdm communication systems, many research papers have addressed blind estimation approaches using subspace schemes [5759].in [60], a blind channel estimation technique is proposed for un-coded ofdm. it is used a constrained linear minimum mean square error (mmse) to estimate an initial data symbol for each subcarrier. the authors claim that the blind system proposed is very favorable, and it can be utilized for high doppler. in [61] however, the authors utilize subspace method to blindly estimate channel for mimo ofdm systems, and in [62], subspace based mimo ofdm system is employed for blind channel estimation considering short averaging periods. different blind estimation techniques that are exploited hos of received signals are presented in [63-65] for mimo systems. furthermore, alamouti stbc (2 × 2) channel with qpsk modulation scheme is studied to estimate doa based on the technique of independent component analysis (ica)[66]. on the other hand, the estimation techniques based semi‑blind require, for channel estimation purpose, known pilot symbols in a combination with the inherent information obtained in the unknown received signals. in [67], the semi-blind approaches are presented using first order statistics to estimate channel coefficients based on superimposing periodic pilot sequences. in ofdm with the space-time block (stb) pre-coded systems as in [68], semi-blind channel estimation is employed. in [69], the semi-blind estimation method is suggested in the case of frequency selective mimo systems. finally, semi‑blind channel estimation employing an orthogonal pilot based ml is proposed in [70]. the channel matrix in this approach is factored into a unitary rotation matrix that can be estimated using an orthogonal pilot based ml from the training symbols and a whitening matrix that estimated using blind algorithms. 4. conclusions a review of fading channel and different channel estimation techniques include; decision directed, the pilot assisted, blind and semi-blind techniques is presented in this paper. variant and invariant multipath cir models are also given in a simple mathematical way. although the blind techniques are very efficient, and training symbols are not required, ahigh computational complexity is a major drawback. consequently, they applied to 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"whitening-rotation-based semi-blind mimo channel estimation." ieee transactions on signal processing 54.3 (2006): 861-869. 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 43 اإلطار العام للعالقة بين التكنولوجيا والتاريخ وأثرها على الهوية في العمارة الماجدي هاشم حسن باسم.د.م العقابي حميد هاشم احمد.د.م التكنولوجية الجامعة – المعمارية الهندسة قسم التكنولوجية الجامعة – المعمارية الهندسة قسم االحد عبد سالم ايناس.م التكنولوجية الجامعة – المعمارية الهندسة قسم الخالصة: بطبيعة تختص والتي الحضارية الحالة عمل لمسار الممثل التاريخي الجانب دور دراسة على العامة الطروحات ركزت في واثرهما المحيطة الظروف تغير بحسب والمادة االنسان بين للعالقة الممثل التكنولوجي والجانب البشري التطور مما. للموضوعين والتحليل بالبحث مختلفة جوانب تناولت االزمان مر على باالنسان المحيطة المعمارية الحالة تشكيل الترابطي الجانب على التأكيد ضعف الى االشارة ضرورة مع لهما وموحد محدد بجانب تتعلق ال عامة رؤية افرز التاريخ من كل بين وتفاصيلها العامة العالقة دراسة نحو البحث لتوجه األساس شكل ما وهذا. بهما الخاص والعالئقي .المعمارية الحالة اطار ضمن التطورية وابعادها والتكنولوجيا الفكرية وابعاده االختالفي الواقع تأسيس في والتكنولوجيا التاريخ من كل دور طبيعة لفهم العامة االسس تعريف الى البحث هذا يهدف طرح من يتكون معرفي اطار لبناء التوجه ثم ومن المعرفية البحث مشكلة لتعريف كأساس ذلك ليطرح العمارة في للهوية حقل من عامة معرفية نماذج بناء ثم ومن نظري كاطار ومتسلسلة متنوعة معمارية طروحات حول عام معماري معرفي النظرية المؤشرات حاالت تحقيق وتوضيح واستكشاف نتائجه وتحليل بالتطبيق القيام الجل االطار ذلك لتقييم العمارة .والتوصيات النهائية االستنتاجات طرح مع العمارة في والتاريخ التكنولوجيا لدور المحددة the general frame for relationship between technology , history and its act on the identity in architecture dr.ahmed hashim hammed al-eqapy dr.basim hassan hashim al-majedy arch. eng. dept. university of technology arch. eng. dept. university of technology enas s. abed el ahaad arch. eng. dept. university of technology abstract: studies has been focused on the role of the historical aspect representative of the course of the work situation of civilization on the nature of human evolution and the technological side on the representation of the relationship between the human and material according to changing circumstances and their impact in shaping the state architectural surrounding human beings over the ages and from several sides dealt with different aspects of research and analysis of the themes which sort overview not related to specific aspect and unified them with the need to refer to the weak emphasis 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 43 on the buzz and feeds on them and this is what formed the basis to guide the search towards the study of the general relationship and the details of both the history and dimensions of the property and technology and the dimensions of the evolutionary part in frame of architecture.this research aims to define the general principles for understanding the nature of the role of history and technology in the establishment of fact the difference of identity in architecture to present a basis for defining the research problem of knowledge and then go to build a framework of knowledge consists of putting up a knowledge architect in on the proposals of architectural variety and sequential framework theory and then to build models of general knowledge from the field of architecture to assess the framework for doing application and analysis of results and to explore and clarify the theoretical investigation of indicators specific to the role of technology in architecture and history and finally presents final conclusions and recommendations. -تمهيد: يؤشر كل من عنصري التاريخ كوعاء زمني لالحداث واالحوال والتكنولوجيا كمحرك واداة لتطور الحياة تأثيراً كبيراً على الواقع المحيط باالنسان وبالتالي على المواقف المتنوعة المحددة لتشكيل اطار الهوية العامة لعمارته. ل طبيعة الترابط الممكن بين عناصر ومميزات وخصائص وهنا يتداخل ويتوازن التأثير العام والفهم المحدد حو كل من المتغيرين السابقين بسبب تشابه االثر العام واختالف االثر النوعي لكل منها، مع تميزالسمة المادية للثاني بشكل اساسي وامكانية الترابط والتفاعل بين سمات كل واحد منهما مع ما يفرضه وجود كال السمتين في احد بين من حالة محددة من التعريف لهما وليؤشر كل هذا االساس االطار العام للعالقة والتأثير الواضح في الجان العمارة والواجب الدراسة في ضوء طرح المعرفة عن كالهما بشكل منفرد وما يمكن ان يوجد من تداخل معرفي ينهما والخاصة بالتأثير المطلوب حولهما وصوالً لتأشير الضعف العام في الطرح المعرفي يشكل االرتباط ب والمرجو منها. وهنا ال بد من االشارة لفردية واهمية تلك العالقة وقيمتها وجدتها وانعكاساتها المتعددة بضوء غياب التغطية المعرفية عنها وما سيفرز من مؤشرات ذات اهمية لواقع الحقل البحثي المعماري منها بدءا بدراسة كال الجانبين ين كل على انفراد ومن ثم توضيح الطرح عن كليهما لطرح االطر المعرفية واجراء التطبيق وطرح السابق االستنتاجات النهائية للموضوع. -وهنا سيتم عرض مشكلة البحث المعرفية مما سبق وكاالتي: التاريخ في " عدم وضوح التصور المعرفي الخاص بتعريف واقع الهوية االختالفي باعتماد عالقة التكنلوجيا و العمارة ". اما هدف البحث فهو كاألتي: " توضيح التصور المعرفي الخاص بتعريف واقع الهوية االختالفي باعتماد عالقة التكنلوجيا والتاريخ في العمارة ." ويوضح منهج البحث في الخطوات االتية: المرتبطة بتعريف واقع الهوية بناء اطار معرفي يتكون من اطار نظري يتم فيه استعراض الجوانب • االختالفي باعتماد عالقة التكنلوجيا والتاريخ في العمارة. 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 43 طرح نماذج معرفية تمثل اطار ومادة للقياس • توضيح واستكشاف حاالت التحقق الخاصة بتعريف واقع الهوية االختالفي باعتماد عالقة التكنلوجيا • والتاريخ في العمارة. .لتاريخ والتكنولوجياالمحور االول: ا. 0 .1.1التاريخ. لغويا . 0.0.0 (. ويحمل هذا القول الكثير 10التاريخ هو الوعاء الزماني الذي تتحرك فيه األشياء نحو غاياتها.)السمرائي، ص من الدالالت والمفاهيم، ولكن قبل ان نوضح ونفصل في ذلك، فاننا نبين أوًل معنى التاريخ لغةً واصطالحاً . يعرف التاريخ في اللغة بأنه تعريف الوقت، والتَّْوريُخ مثله، وقيل: إِن التأْريخ مأْخوذ منه كأَنه شيء َحَدث كما يَْحُدُث الولد. وقيل: التاريخ مأْخوذ منه ألَنه حديث ،ويقول الرازي )"التاريخ" و"التوريخ" تعريف الوقت، تقول : احد(، وترى بعض اآلراء وجود أصول غير عربية، فارسية أو سريانية أرخ الكتاب بيوم كذا، و"ورخه" بمعنى و للكلمة، واما علم التاريخ فهو علم يبحث فيه عن الزمان وأحواله، وعن أحوال ما يتعلق به من حيث تعيين ذلك به ( بمعنى علم التاريخ والمعرفةhistoryوتوقيت.)المعجم اللغوي(. وفي قاموس اوكسفورد ترد كلمة التاريخ) ( تعني المسار والتطور thehistory ofوهو دراسة األحداث الماضية وخاصة في الشؤون اإلنسانية و) (. لذا oxford dictionariesالتاريخي والتسلسل الزمني لألحداث الهامة عادة أو عامة أو من اتجاه معين.) ة وفي مدى ومسار وتطور خاص للحدث فالتاريخ يختص كعلم بالبحث في احوال الزمان الممثلة لالحداث الحاصل المهم الى االقل اهمية. اصطالحيا . 0.0.3 يرد التاريخ كاصطالحاً ويعني جملة األحوال واألحداث التي يمر بها كائن ما على الفرد أوالمجتمع كما يصدق على الظواهر الطبيعية واإلنسانية ، فالتاريخ يعنى بدراسة الزمن فيما يتعلق باإلنسان وهو دراسة الماضي ت الحاضر وكل ما يمكن تذكره من الماضي أو تم الحفاظ بالتركيز على األنشطة اإلنسانية في الماضي وحتى الوق عليه بصورة ما يعد سجال تاريخياً ، ويقول الدكتور قاسم عبده )أن هناك تفريق شائع بين كلمة التاريخ كتعبير دال على مسيرة اإلنسان الحضارية على سطح كوكب األرض منذ األزل وعبارة تدوين التاريخ كتعبير عن العملية (. وقد history-philosophyية اإلنشائية التي تحاول إعادة تسجيل وبناء وتفسير اإلنسان على كوكبه(.)الفكر عّرف ابن خلدون التاريخ بأنه خبر عن االجتماع اإلنساني الذي هو عمران العالم وما يعرض لطبيعة ذلك يس هو الحوادث وإنما هو تفسير ( .ويذهب سيد قطب إلى أن التاريخ ل213العمران من األحوال.)ابن خلدون، ص هذه الحوادث واالهتداء إلى الروابط الظاهرة والخفية التي تجمع شتاتها وتجعل منها وحدة متماسكة الحلقات (. اما 371متفاعلة الجزئيات ممتدة مع الزمن والبيئة امتداد الكائن الحي في الزمان والمكان.)قطب، ص االحداث حول الفرد والمجتمع على مدى الزمن ويتخصص هذا الطرح اصطالحاً فالتاريخ هو اطار لمجموعة الزمني بمعالجة ودراسة الماضي بعرض كل ماهو خاص بطبيعة العمران وترابط الحوادث والظواهر. . فلسفيا 0.0.2 رار من يعرف التاريخ لدى )هايدكر( بأنه شكل من أشكال التفسير والتفكير والتأمل وليس مجرد الجمع والتك -historyالقصص عن الماضي انه عملية الكشف عن نظام تطور الطبيعة البشرية في مراحل متتالية.) philosophy (. في حين فسر)هيجل( حركة التاريخ انطالقاً من منهجه الجدلي ومن فكرة صراع المتناقصات ..وهكذا الى ان يصل الى المطلق الذي يبدأ من الفكرة والنقيض ، فالمركب الذي يحمل في الوقت نفسه نقيضا.. بعدما بدأ من المطلق وهذه الحركة الدائرية التي ينطلق فيها الروح او الفكرة المطلقة عند هيجل وفق حركة جدلية (. 37يغذيها التناقض او الصراع بين المتناقضات في سلسلة من الهدم والبناء نحو تحقيق االفضل.)تيزيني، ص 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 43 لتاريخ الذي يهيمن على الوقائع ويصوغها ضمن منطقها الداخلي من خالل تفاعل التاريخ الحقيقي هوذلك ا الشخصيات التاريخية نفسها مع المقصد الخفي الذي يبلوره المنطق الباطني للتاريخ حيث يقوم التاريخ وفقاً لهذه ين يراد له أن يبسط الفلسفة بتفسيرالوقائع واستخراج القوانين والتنبؤات لما سيجرى من غير التقيد بزمن مع قوانين وآلية جريان أحداثه على زمن آخر والسبب في ذلك أن العقل كما يراه )هيجل( هو جوهر التاريخ ومن ثم فهذا العقل هو الذي يتحكم في أحداث العالم عن طريق التاريخ نفسه وبالتالي فكل حدث من أحداث التاريخ إنما األحداث العالمية لتخدم قصداً معيناً أو هدفاً محدداً ولكن من تحت مظلة جرى وفقاً لمقتضيات العقل الذي يموضع التاريخ.)العلفي(.هذه الفلسفة في النظرة للعقل باعتباره جوهر التاريخ تقتضي نظرة معاكسة للنظرة التقليدية ة أو التي ستجري بأنها السائدة عن التاريخ التي تعتمد على جعله مهميناً على العقل بتوقع سيناريو لألحداث الجاري ستكون على سيناريو مشابه ألحداث تاريخية سابقة مشابهة، أما فلسفة التاريخ الهيجلية فعلى العكس منها بحيث تعتبر العقل نفسه هو من يسير التاريخ بحيث يرتب أحداثه على نحٍو يجعلها سائرة نحو هدف أومقصد بعيد المدى جل( عبارة عن منظومة تطور ونمو خاضعة لمنطق باطن كامن في وعلى هذا النحو فالتاريخ لدى )هي الشخصيات التاريخية التي لم تكن وفق هذه الفلسفة إال أدوات لتحقيق فلسفة أوهدف التاريخ السائر بشكل حتمي (. alriyadhنحو تحقيق مقصد معين.) ة اعتماداً على دراسة المتناقضات فلسفياً التاريخ هو تغيير المسار الزمني الممثل لتطور الطبيعة البشري المتصارعة كون التاريخ هو ما يهيمن على الوقائع ويصوغها ضمن منطق محدد من خالل تفاعل االدوار التاريخية التي تجري وفقاً لمقتضيات العقل المحدد لالحداث لخدمة هدف معين.وهنا فالرؤية تحدد هيمنة العقل ى العكس لتكون النتيجة هي خضوع التاريخ لمنطق باطني كامن في على التاريخ في مقابل رؤية اخرى تر الشخصيات التاريخية التي هي ادوات لتحقيق اهداف التاريخ المطلوبة. . التاريخ والحضارة0.3 إن الفرد والمجتمع له القابلية على التوفيق بين بيئته وبين ذاته لكي يكون مؤهال للتكيف للظروف المحيطة دة وذلك من خالل التغير والتفاعل الزمني من نواحي المعرفة التي يستقبلها وتفاعلها مع ثقافات وحضارات الجدي أخرى وازدياد هذا التفاعل بصورة متوازنة مع أسس الكلية التاريخية والذي يدفع المجتمع إلى التطور في التطور الفكري للمجتمع يجب أن يكون باستمرارية ويزيد من القيم اإليجابية للتكيف الن التغير الذي يحصل متزنا بحيث ال يؤدي االستقبال المباشر وغير المنتظم للمؤثرات الخارجية إلى إرباك نتائجه ليحصل فقدان الثقة لدى المجتمع بمعاني حضارته وحدوث شعور ببطالن وانتهاء دور المراحل التاريخية ويبدأ المجتمع بفقدان .(. 32salya,pه ويستقبل التيارات والحركات الفكرية العالمية بشكل غير مسيطر عليه.)حلقات أساسية في هويت ان لكل حضارة أساس وهذا االساس ال يمكن معرفته اال من خالل الرجوع الى االصول او التاريخ الذي كان قد ى الدوام او االستمرار بل حدث حيث يكتسب اهمية لم تكن تخطر في الذهن قط اذ ال يفهم العالم اال كنظام قائم عل ان العالم يفهم كتاريخ نتيجة للتاريخ الماضي ومكان للتاريخ الحادث فالعالم حادث وهو متغير وهو لذلك قابل للتغير أيضا وبهذا المفهوم نرى ان أهمية التاريخ كأساس لمعرفة الحاضر من خالل مقولة تؤكد ان االشياء ليست ها هللا والطبيعة وحسب بل ان االشياء رهن للتاريخ اي انها مشروطة تاريخياً وهي وليدة عملية خلق وابداع قام ب مرتبطة بأزمنتها ولذا فاننا اذا ارادنا ان نفهم الحاضر البد لنا من فهم اصوله التاريخية واذا اردنا التغلب على لكل انسان فعلينا اللجوء االنقطاع بين الحاضر والماضي وتجنب خسارة الضمانات التي يومنها الشئ المستمر (2الى التاريخ لنلوذ باالستمرارية والثبات.)نيبارداي، ص ترتبط الحضارة بعالقة توافق وتوازي مع التاريخ الجل التكييف بين الظروف المحيطة الجديدة بسبب التغيير حضاري بشكل موازي ومتوازن والتفاعل بين الحضارات المختلفة وهذا ما يحدد مساراً اخر للترابط والتوافق ال مع االسس التاريخية باسلوب االستقبال المباشر للمؤثرات الخارجية ففي كل حضارة يوجد حدث يكتسب االهمية القصوى ويكون هو محور أو مرجع التنظيم التاريخي ، اذ ان االشياء واالحداث مرهونة بالتاريخ ومرتبطة سلي لالحداث تاريخياً ضمن اطار االستمرارية التاريخية الحضارية.بازمتها وهذا ما يوضح طبيعة الفهم التسل 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 43 .1.1التكنولوجيا . لغويا واصطالحيا 0.2.0 oxfordعرف معجم اكسفورد الحديث التكنولوجيا بانها المعرفة العلمية التي تستخدم لغرض صناعة معينة.) dictionariesات التقنية في عموميتها وفي عالقتها بالحضارة.)القاموس ( .ان التكنولوجيا هي مجموع العملي الفلسفي،الوالند(. فهي ليست مجرد علم او تطبيق العلم او مجرد اجهزة بل هي اعم واشمل من ذلك بكثير فهي نشاط انساني يشمل الجانب العلمي والجانب التطبيقي، ويلخص )حسين كامل بهاء الدين( رؤيته لمفهوم ئالً )ان التكنولوجيا فكر وأداء وحلول للمشكالت قبل ان تكون مجرد اقتناء معدات فهذا التداخل التكنولوجيا قا الوثيق بين العلم والتكنولوجيا ازال معه الحواجز الزمنية نتيجة لذلك اصبح العلم هو االساس المؤكد لكل تحول ك ليس من السهل الفصل والتمييز بين تكنولوجي وهذا االمتزاج هو المصدر االول لقوة االنسان المعاصر وبذل (. وجاء تعريف )أشبلنجر( للتكنولوجيا في كتابه )االنسان و التقنية( بانها 22العلم والتكنولوجي(.)القيسي،ص (. كما يرى 32جزء من الحضارة ويقول بانها فن الحياة فهي اذن مرحلة من مراحل الحياة.)اوزياس،ص (mcclearyبان التكنولوجيا ليس ) ت فقط النواتج النهائية او العمليات التي تقوم بانتاجها بل تتضمن الجهود الفكرية التي تسهم في انتاج الفعل التقني وتقوده وتتحاور معه بحيث يمكن القول بان فكرة التكنولوجيا تعبر عن نسانية اذ اننا االن ( .اما )ممفورد( فيعرفها عبر ارتباطها بالطبيعة االmccleary,p.24فن وعلم الحضارة. ) نمر من الحالة البدائية لالنسان والمميزة بفرض سيادته على قوى الطبيعة الى حالة تختلف عنها جذرياً فيما ال (.332يكون قد تغلب على الطبيعة فحسب وانما يكون قد فصل نفسه تماماً عن البيئة العضوية.)كوانبرج ،ص ت تقنية او نشاط انساني يشمل الجوانب العلمية والتطبيقية اما التكنولوجيا تطرح لغوياً كمجموعة عمليا اصطالحياً فهي فكر يتعلق بتطبيق وايجاد حلول للمشكالت وهي جزء من الحضارة ومرحلة من مراحل الحياة متضمنة الجهود الفكرية التي تسهم في انتاج الفعل التقني وتترابط مع الطبيعة االنسانية بشكل انتقالي ومستمر. . فلسفياً 0.2.3 عرف )هايديكر( التكنولوجيا بأنها طريقة لكشف او اظهار الماهيات والحقائق بمستويين: االول باظهار ماهية الظواهر وبهذا يعيد االنسان تشكيل بيئة باشكال جديدة. • عتماداً على الثاني باظهار ماهية الطبيعة االنسانية وقدرتها على التحرر وصنع حياة يحققها االنسان ا • مهاراته. فالتكنولوجيا ال تكون اداة فحسب و)هايديكر( يؤكد على ذلك بقوله )النقطة الحاسمة في التكنولوجيا ال تكمن البتة في فعل الصنع او المعالجة كما ال تكمن في استخدام الوسائل ولكن في الكشف الذي نتكلم عنه )احضارا أو (. فماهية التكنولوجيا heidegger,p.238صفها كشفاً ال بوصفها صنعاً.)ظهورا( الن .التكنولوجيا انتاج بو الحديثة تضع االنسان على درب هذا الكشف الذي به يصير الواقع رصيدا في كل مكان بشكل يمكن ادراكه (. ان التكنولوجيا تدل على ما يمارسه االنسان من افعال يحول بها تصوراته 323بدرجة ما.)فولكوف،ص الى واقع معاش ولذا يتحدد جوهر الفعل التكنولوجي لدى )هايديكر( بـــاظهار العالقة الجدلية بين ورغباته الحضارة والطبيعة وتجليها فيما يصنعه االنسان من حيث ان تغير الفعل التكنولوجي عبر تاريخ العمارة يتم ليتحدد نمط معالجته للمحيط بحسب تمثيله لعالقة االنسان والعالم المعطى ضمن توجهات ومقاصد متعددة (. architecture knowledge managementالوجودي بحسب حاجاته ورغباته. )المكتبه االفتراضيه، اذ يمتلك فعل االنسان لمستوين متداخلين: الثقافة والتكنولوجيا اللذان يسندانه في كشف واظهار ما للطبيعة من قيم االداتية لتربط فكر االنسان مع الطبيعة اذ يعرف فعل االنسان بانه نتاج السيرورات مولدة تساهم في انتاج قيمتها الطبيعية والكوزمولوجية والنمو البيولوجي ليشكالن معاً اسناداً يجعله يمتلك طبيعة متعالية.)المكتبه (.spaces of global cultures: architecture, urbanism, identityاالفتراضيه، 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 43 فلسفياً التكنولوجيا هي طريقة لكشف االشياء وعلى مستويات عدة فيما يتعلق بالظواهر ومنها مايتعلق بالطبيعة االنسانية فهي فعل كشف وليس فعل صنع بحيث يجمع ذلك رصيداً للواقع في كل مكان وبشكل يمكن ادراكه. لذا ول تصوراته الى واقع حقيقي وقد مثل تغير الفعل فان اثرالتكنولوجيا يظهر فيما يمارسه االنسان من افعال ليح التكنولوجي عبر العمارة وتاريخها على اساس تمثيل عالقة االنسان والعالم المعطى ضمن توجهات محددة حيث يتفاوت فهم التكنولوجيا كفعل انساني بحسب الظروف المحيطة وتغير الحاجات والقيم والقواعد. . التكنولوجيا والحضارة0.1 ان العمل المعماري لكي يكون مترابطاً بزمنه او معاصراً يجب ان يكون جزءاً من النشاط الحضاري القائم في حياة المجتمع اليومية ومتوافقاً مع الدرجة الحاضرة التي وصل اليها االنسان من المعرفة على كل الجبهات ة التي ال يمكن الفصل بينها في التصميم المعماري في مجال العلوم اإلنسانية والعلوم الطبيعية والميكانيكي (. وضمن مفهوم الحضارة الشمولي تمثل التكنولوجيا مفهوماً يؤكد الوجود 32، ص0332والتخطيط.)السيد المتحقق تارة ومتضمناً الوجود السابق المتحقق تارة اخرى وهذا السلوك يقع ضمن عالم المحسوس ويندرج تحت تدل بذلك على جملة مظاهر التقدم العلمي والتقني التي تنتقل من جيل الى آخر في مجتمع مفهوم التكنولوجيا ف واحد او عدة مجتمعات ثم لتشير بذلك )التكنولوجيا( الى الظواهر بانتقالها من اشكالية التحقق الى التحقق ان التوجه االلي ال ينتج من (. وهذا ما دعى اليه )هابرماس( اذ انه البد من التأكيد على21-21بالفعل.)توفلر،ص التكنولوجيا ذاتها وانما من طبيعة الدور الذي يعطيه االنسان لها فالتقنية ال تحمل في طياتها الغاء لالنسان (. كما انه ال 00والحضارة االنسانية بل تقع على البشرية مسوؤلية ضبط الجهاز التكنولوجي.)هابرماس، ص نية وحدها واالرجح انه البد من الشروع في نقاش يربط اإلمكانات االجتماعية يمكن مواجهة تحدي التقنية بالتق (. فتشكل بذلك التكنولوجيا جانباً مهماً 021للمعرفة والمقدرة للتقنيات بالمعرفة واإلرادة العمليتين.)هابرماس،ص ارة حيث يتكون هذا وفاعالً في الحياة بصورة عامة والعمارة بصورة خاصة وتؤثر بقوة في تكوين تاريخ الحض التاريخ من تفاعل متبادل بين قوتين تدعمان وتهيمنان على االنسان في آن واحد )التكنولوجيا التي توسع افق عمله (.07،ص0323الى ما ال نهاية والمجتمع الذي يمدد حياتها الى ما ال نهاية(.)كرم اطاره العام بما فيما الفعاليات المعمارية التي يؤثر النشاط الحضاري كل الفعاليات العامة التي تحدث ضمن تحتوي اضافة لغيرها من الفعاليات على فعل تكنولوجي يحدد مظاهر للتقدم والتطور العلمي والى ظواهر تنتقل من اشكالية التحقق الى مرحلة التحقق بالفعل كون التكنولوجيا تنتج من طبيعة الدور التي يعطيه االنسان لها بحيث الحضارة االنسانية ضبط وتنظيم الحالة التكنولوجية من خالل االمكانات االجتماعية والحضارية للمعرفة تحدد باالدارة التقنية والعملية. الن التكنلوجيا ستساعد وتؤثر بهذا الشكل على تكوين التاريخ الحضاري باعتماد تفاعلها مع المجتمع. )المحور العام( -مناقشة : لطرح العام حول كون التاريخ مسار زمني يمثل تطور الطبيعة البشرية باعتماد دراسة المتناقضات بالنظر ل من خالل صياغة الواقع المعتمد لتفاعل االدوار التاريخية وهذا كله يجري وفقاً لمنطق باطني كامن وكون ة مع الطبيعة االنسانية بشكل مستمر التكنولوجيا تتعلق بايجاد الحلول للمشكالت ضمن االنتظام العام لمراحل الحيا لكل الشياء وعلى عدة مستويات ظاهرية وخاصة بالطبيعة االنسانية ، فان التكنولوجيا كفعل تغير عبر تطور العمارة على اساس تمثيل عالقة االنسان والعالم بحسب تغير الظروف المحيطة والحاجات يصل البحث لطرح زي مع التاريخ وبشكل تكيفي بحسب الظروف المتغيرة باسلوب االستقبال ترابط الحضارة بعالقة توافق وتوا المباشر للمؤثرات الخارجية وبشكل تسلسلي لالحداث التاريخية ضمن اطار االستمرارية. اما فعل التكنولوجيا بحسب الدور فهو المحدد لمظاهر التقدم العلمي والى نقل الظواهر من اشكالية التحقق الى مرحلة التحقق بالفعل و الذي يعطيه االنسان لها بحيث تحدد الحضارة االنسانية ضبط وتنظيم الحالة التكنولوجية بربطها باالمكانات االجتماعية والحضارية ليؤثر كل هذا في تكوين التاريخ الحضاري . 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 من اطار مما سبق يتوضح الترابط والتوازي بين المسار التسلسلي الحضاري التكيفي للتاريخ ض االستمرارية وبين دور التكنولوجيا المستمر تاريخياً في تكوين التاريخ الحضاري وهذا ماسيقود البحث لطرح محوره العام وكاالتي " العالقة الترابطية بين التكنلوجيا والتاريخ في العمارة " . التاريخ والهوية المعمارية 1.1 ان التفسير الديناميكي للهوية مرتبط بالنظرة النسبية التي ترى التاريخ علىى إنىه عمليىة متتابعىة للتطىور تمتلىك فيها القيم الحضارية حقيقة نسبية وإن هذا الموقف النسبي ال يعنىي إن المجتمىع ال يحمىل ذاكىرة مرتبطىة بالماضىي لمجتمع تكىون قابلىة للتغييىر بصىورة جديىدة ، كمىا ال يجعىل مىن بل يعني إن هناك أصوالً وثوابت ينطلق منها هذا ا هىىذين المىىوقفين خيىىارين مختلفىىين بىىل إنهمىىا متالزمىىان ألنىىه غالبىىا مىىا يكىىون الموقىىف النسىىبي نتيجىىة لنقىىد الموقىىف المعياري التاريخي وهذا ما حصل عندما ظهرت العمارة الحديثة كاتجاهاً نسبي وضعي علىى أنقىاض الكالسىيكية (. ان دراسة التاريخ هي افضل مىن اي تحليىل للحاضىر 031دة المعيارية في القرن التاسع عشر.)النعيم، صالجدي وذلك ألن التاريخ مكتمل ومنتهي وهو المسىؤول عىن اجابىة السىؤال مىن نحىنا و لمىاذا نختلىف عىن غيرنىاا وهىو فىين عىن غيرنىا وكىون غيرنىا مختلفىين المسؤول عن هويتنا ايضاً وهو يقدم لنا هويتنىا ويىدع لنىا صىدفة كوننىا مختل وهو ما يجعلنا نختار من نناهض ومن نتقبل ونتحمل فالشك ان لتقبل كوننا بهذه الصورة وكىون اآلخىرين بصىورة فىي حديثىىه )محمىد ماجىد خلوصىي((. ويشىير 01اخىرى اثىر اخالقىي للتعامىل االيجىابي مىع التاريخ.)نيبىىارداي،ص هىو ثابىت ومتغيىر فيىه ف من دراسة التاريخ ليس التذكر فقط وانما اسىتنباط مىاحول الخلفية التاريخية الى ان الهد فاستعراض الخلفية التاريخية تتيح لنا معرفىة الخىط الثابىت عبىر االزمنىة الماضىية وكىذلك معرفىة المتغيىرات التىي ط بىل يعنىىي (. لقىد انتبىه المعمىار إن الىزمن ال يعنىي الىبالء والىزوال فقى322ارتبطىت بعصىر معين.)خلوصىي،ص أيضا الحياة وخصوبتها بإعادة تكوين األشىياء وتطويرهىا وإن هىذا يىتم فىي صىورة تراودنىا وتىدفعنا دومىا لمحاولىة التحكم في صيرورتها ومن هذه الحيثية الزمىت عمليىة اسىتقراء التىاريخ والعمىارة التاريخيىة إشىكالية الخصوصىية عاصىىرة ذات رسىىوخ زمنىىي ومكىىاني األمىىر الىىذي يصىىب مىىن جانىىب تكوينهىىا و عمليىىة تفعيلهىىا إلنتىىاج خصوصىىية م (.020مباشرة في تعريف مفهوم الهوية. )بودماغ،ص ان العمارة تعبير حي لثقافة الشعوب وهي ارقى ما تتوصىل اليىه االمىم والشىعوب مىن منجىزات وال ادل علىى ل وسومر وفي وادي النيل وغيرهىا مىن ذلك من االثار التي خلفتها الحضارات القديمة في بالد واد الرافدين في باب الحضارات والتاريخ حافل بمخلفات واثار الحضارات القديمة المتمثلة في عمارتهىا ومنشىاتها الهندسىية فهىي دليىل تشىكل العمىارة التاريخيىة الشىعور القىومي او (. كما72على التفاعالت الداخلية لروحية الحضارات.)كمونة ، ص ي كل مرة نتناسى هذا الشعور فأننا ننسى التاريخ اي ننسى المستقبل بمعنىى آخىر فىأن هي جزء من هذا الشعور وف المسار الموازي التكيفي للتاريخ مسار تسلسلي حضاري مسار حضاري استمراري مسار التكنولوجيا المستمر تاريخيا مسارات تكوين التاريخ الحضاري ( يوضح المحور العام للبحث )توازي مسارات التاريخ والتكنولوجيا وفقاً العتماد مسارات تكوين التاريخ 1-1شكل) الحضاري( 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 العمارة االعتباطية هي عمارة بال جذور وهىي ايضىاً بىال مسىتقبل فالعمىارة التاريخيىة هىي المرجىع االسىاس لبنىاء نع الحيىاة وتىرتبط (. وهي بذات الوقت آداة بناء حضارية تسهم فىي صى23عمارة حاضرة ومستقبلية.)البهنسي،ص . فالعمارة تمتىد خىارج حىدود مكىان وزمىان (conrads, 1970,p.74)بعالقة جدلية ازلية مع عناصرها المتعددة. ان سىمات .(lynch ,p.53)والدتهىا او الطبقىة االجتماعيىة المسىوولة عىن ظهورهىا او الطىراز الىذي تنتمىي اليىه. العمارة المتعلقة بصفتها ظاهرة حضارية هي سمات تحمل صفة الفردية والتغير تبعاً لعىاملي الزمىان والمكىان فقىد اسىىتطاعت العمىىارة ومىىن خىىالل اسىىتمرار حضىىورها عبىىر فتىىرات طويلىىة مىىن الزمىىان ومقاومتهىىا الدائمىىة لعوامىىل (. ومىن هنىا فىان أهميىة العمىارة ال تكمىن فىي 2صومؤثرات الىزمن فىي دراسىة طبيعىة وثقافىة مجتمعاتها.)الخيىاط، كينونتها كشاخص حضاري لمجتمع ما في فترة معينة فحسب وانمىا فىي ديمومتهىا ومقارعتهىا للىزمن وتمكيننىا مىن (. وهذا يوضح مقولىة 02معرفة فكر الكثير من مجتمعات التاريخ ومجتمعات لم يعثر على مدوناتها.)المنشدي،ص نرى فيها كل التغيرات الفكرية واالجتماعية في عصر مىا ولمجتمىع مىا وان حقيقىة كىون ان العمارة مرآة عصرها العمارة جزًء مىن النتىاج الحضىاري للمجتمىع الىذي يحمىل معىاني رمزيىة دالليىة تعبىر عىن واقعىه يمكىن أن تنىدرج ة إلى كونها تحقق ضمن عمليات تحقيق الذات التي تصنف في أعلى هرم الحاجات اإلنسانية وان العمارة باإلضاف وتقدم الحاجات األساسية لإلنسان فهي توفر أيضا لإلنسان والمجتمع قيماً ثقافية واجتماعية متميزة تحقىق الىذات او (.2-1الشخصية من خاللها.)الخياط،ص ية ان الهويىة المعماريىة تفسىىر اعتمىادا علىى رؤيىىة التىاريخ كعمليىة متتابعىىة تمتلىك القىيم الحضىىارية فيهىا حقيقىة نسىىب بحيث ينطلق المجتمع من ثوابت محددة فالتاريخ مسؤول عن هوية المجتمع وعن اختالفه عن غيره اذ يساعد فىي استنباط ما هو ثابت ومتغير وذلك من خالل التفكير في الزمن وتصور ابعاده للوعي بىاختالف االجيىال واحىد عىن يىة المتغيىرة بشىكل يعيىد تكىوين االشىياء وتطويرهىا االخر وهذا ينطبق على العمارة التي تعني بكىل المراحىل الزمن لينتج خصوصية معاصرة ذات رسوخ زماني ومكاني ويشكل الهوية بالمحصلة فالعمارة تاريخياً هي مرجىع لبنىاء االفاق المسقبلية ، وهي ما يبني الحضارة ويعبر عن هوية المجتمعات بحيث تكون سمات العمارة الخاصة بكونهىا مل صفة الفردية والتغير باعتماد اختالف الزمان والمكان لتتجلى اهمية العمارة في ديمومتهىا ظاهرة حضارية تح ومقارعتها للزمن ورؤيتنا للكافة التغيرات الفكرية واالجتماعية في العصور والمجتمعات من خاللها. . التكنولوجيا في العمارة )رؤية عبر التاريخ(.1.1 ل حقبة تأريخية يعد امتالكها والتحكم بها رمزاً للقوة والسىيطرة فىي ذلىك العصىر ان شيوع تكنولوجيا معينة في ك (. وان 32وقىىد يكىىون هىىذا السىىبب الىىذي يىىرى فيىىه الىىبعض بىىأن التكنولوجيىىا تتصىىف بالبيروقراطيىىة.)ممفورد،ص االنتىاج او تعتمىد التقسيمات التاريخية لتحديد الفترات التكنولوجيىة تعتمىد اغلبهىا الوسىيلة التكنولوجيىة الطاغيىة فىي المىىادة المسىىتخدمة والداخلىىة فىىي كافىىة الظىىواهر الحياتيىىة االخىىرى او العالقىىة القائمىىة فىىي صىىيغة ائىىتالف العناصىىر البشرية واألدوات التكنولوجية واخيراً على النشاط المهىيمن فىي ذلىك العصىر الىذي بىدوره يىدخل فىي كافىة انشىطة نىىرى ان بعىىض المختصىىين يرجعىىون تىىاريخ التكنولوجيىىا الىىى العالقىىة الحيىىاة وفىىي المجىىاالت االخىىرى وتبعىىاً لىىذلك األزلية بين االنسان والمعادن وكذلك سىعيه التعىديني عبىر المراحىل المختلفىة لمسىيرته وكيىف كانىت المعىادن ومىا -زالت ركناً اساسياً قام عليها بنيان حضارته وتطورت بتطوره وهذا يقسم الى االتي:  ي فتىىرة العصىىرين الحجىىري القىىديم والجديىىد( وفيهىىا اكتشىىف االنسىىان المرحلىىة األولىىى: )وهىى مجموعة من الصخور والمعادن التي احدثت انعطافىة فىي حضىارته التكنولوجيىة مىن حضىارة حجرية الى حضارة فلزية )معدنية(.  المرحلة الثانية: )وهي مرحلة بداية التاريخ ونشوء الحضارات( وفيها اخترع االنسان الكتابىة تىىدوين وتمثىىل حقبىىة بنىىاء األهرامىىات الفرعونيىىة اول صىىناعة اسىىتخراجية كبيىىرة مارسىىها وال االنسان.  المرحلىىىة الثالثىىىة: )وهىىىي مرحلىىىة عصىىىور النهضىىىة العلميىىىة واالصىىىالح والثىىىورة الصىىىناعية والتكنولوجيىىة( حصىىل تحىىول نىىوعي فىىي السىىمات الحضىىارية لألنسىىان ففىىي مجىىال المعىىادن ( معىدن ويحىدد خواصىها 0211ع االنسان ان يكتشىف اكثىر مىن )والعناصر المكونة لها استطا ومكوناتهىىا فكىىان الفحىىم والبتىىرول واليورانيىىوم عنىىاوين بىىارزة ومتسلسىىلة لسىىمات عصىىور هىىذه (.23-21المرحلة.)العطية،ص ان اهم متغير تكنولوجي حدث في تىاريخ العمىارة والعلىوم هىو الثىورة الصىناعية واختىراع ماكنىة البخىار حيىث ان منتصف القرن التاسع عشر وحتى نهايات القرن العشرين تعد المدة التي شهدت انجازات وابتكارات مهمىة ثوريىة ريىت تعىد االكثىر اهميىة هىي المىواد المكتشىفة غيرت دور وتأثير االبنية كمىا ان اكتشىاف الحديىد والزجىاج والكونك على االطالق والتي ساعدت على انجاز ما يمكن انجازه في خالل مدة ال تتجاوز المئتي عىام مىن تىاريخ ظهورهىا فتطور االنسان من حياة المغارة الى بناء عمارة لم تكن بجهود فرد معين أو فئة معينة بل ساهمت البشىرية جمعىاء وتطورات على مسىتوى المىادة والفكىر ليبتكىر االنسىان كىل مرحلىة تسىاعده باالنتقىال الىى المرحلىة في هذه العملية الثانية فقد بدأ يضع ادواته واالتىه ثىم بتطىوير مسىكنه ومادتىه البنائيىة وصىوالً الىى بنىاء مسىتوطنات ومىدن وعمىائر كىل يىوم وفىي مكىان العمىل حتى اصبحت العمارة سمة اساسية من سمات عصرنا وهي تحيطنا في كل مكان وفىي 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 وفىىىىىىي مكىىىىىىان التسىىىىىىوق وحتىىىىىىى فىىىىىىي اوقىىىىىىات الراحىىىىىىة وفىىىىىىي المالعىىىىىىب والمسىىىىىىارح والمتاحف.)المكتبىىىىىىه تتطىىور بىىذلك الصىىيرورة التكنولوجيىىة بصىىفتها .(architecture knowledge managementاالفتراضىىيه، تكتمل هذه الصىورة فىي عهىد صيرورة تاريخية وتتحول وظائف عمل االنسان بمقتضاها الى وسائل تكنيكية حيث االتمتىىة مىىن تطىىور التكنولوجيىىا وهىىذا التطىىور مىىن التكنولوجيىىا يبشىىر بمىىيالد علىىوم جديىىدة واضىىعة فىىي العىىد النظىىام البشري مثل )السيبرنتيكا( ويماثل )فالكوف( بين هذا النوع من التكنولوجيا والتكنولوجيا البدائية وذلىك مىن منطلىق ن يحىدث تلقائيىاً وبصىورة عفويىة علىى امتىداد تىاريخ تطىور التكنولوجيىا اذ ان مىا كىان ان ما تقوم به هذه العلوم كىا اداة( اوتوماتيكيىىة ذات تحكىىم مبىىرمج –يصىىنعه االنسىىان الحجىىري بفأسىىه مىىثالً هىىو نفىىس مىىا تصىىنعه اليىىوم ثمة)الىىة والنشىاطات المهيمنىة (. تعتمد التكنولوجيا التقسىيم التىاريخي لفهىم كافىة الظىواهر الحياتيىة المحيطىة02.)فرج، ص تقنيا في اي عصر مىن العصىور كىون تىاريخ التكنولوجيىا يعتمىد احيانىا علىى العالقىة االزليىة بىين االنسىان والمىادة وتطورها عبىر مراحىل مختلفىة يطىرح تصىنيفها العىام بشىكل يوضىح وجىود تحىول نىوعي فىي السىمات الحضىارية يىىر تكنولىىوجي اخىتص بىىالثورة الصىناعية واكتشىىاف الحديىىد لالنسىان. ومنهىىا مىا توضىىح فىىي تىاثر العمىىارة بىاهم متغ والزجاج والكونكريت وما ساعدت على انجازه وبالتالي وضع العمارة كسمة اساسىية مىن سىمات العصىر وجعلهىا محيط عام ومستمر للفرد وتشكيل بيئته. وهنا تتطور الضىرورة التكنولوجيىة كونهىا ضىرورة تاريخيىة كىون الفعىل سىىاني متىىداخل مىىع المنظومىىات المعرفيىىة واالخالقيىىة ويسىىاهم فىىي تكىىوين الكىىل الثقىىافي المميىىز التكنلىىوجي فعىىل ان للمجتمع بحيث ينشأ بعد اخالقي للعمارة من التكنلوجيا بقصد تشكيل خطاب حضاري وثقىافي يؤسىس لىنمط وشىكل معرفي للحياة متالئم مع العصر والمكان والمجتمع. -مناقشة )المحور الخاص(: ية الهوية المعمارية تاريخيىاً صىيغة لتعريىف النتىائج فىي عمليىة امىتالك القىيم الحضىارية الحقيقيىة نسىبية تشكل رؤ تحدد انطالقة المجتمع من ثوابت محددة كون التاريخ هو ما يشكل هوية المجتمع المختلفة عن غيره بطرح الثابىت تىىي تقيىىد تكىىوين االشىىياء وتطويرهىىا النتىىاج والمتغيىىر مىىن خىىالل التفكيىىر بىىالزمن وهىىذا مىىا ينطبىىق علىىى العمىىارة ال خصوصية معاصرة ذات رسوخ زماني ومكاني وتحمل صفة الفردية والتغيىر مىن خىالل ديمومتهىا واسىتمراريتها ومقارعتهىا للىىزمن امىىا التكنولوجيىىا فتعتمىىد االطىار التىىاريخي لفهىىم كىىل مىىا يحيطهىا ضىىمن اي عصىىر مىىن العصىىور االنسان والمادة المتطورة عبر االزمىان وبتحىول نىوعي فىي السىمات الحضىارية باعتماد تاريخها على العالقة بين لالنسان ، فتطور صيرورة التكنولوجيا كصيرورة تاريخية ياتي من ان الفعل التكنولوجي فعل انساني متداخل مىع المنظومات المعرفية واالخالقية لتاسيس نمط معرفي للحياة يالئم العصر والمجتمع . ضح الواقع المعماري المحدد لدور الهوية االختالفي عبر الزمن في تاطير واقىع كىل مىن التكنولوجيىا مما سبق يتو المعتمدة على الفعل االنساني وعالقته بالمادة من خالل التداخل مع المنظومىات االخىرى والتىاريخ المعتمىد الثابىت ذا مىىا سىىيقود البحىىث لطىىرح محىىوره والمتغيىىر فىىي تشىىكيل االشىىياء وتطويرهىىا النتىىاج الخصوصىىية المعاصىىرة وهىى الخاص وكاالتي: " التكنلوجيا والتاريخ واثر روح العصر على الهوية في العمارة ". التكنولوجيا المادة الفعل االنساني تأسيس لواقع اختالفي باعتماد التكنولوجيا تأسيس لواقع اختالفي باعتماد التاريخ الناتج النهائي للواقع االختالفي )الهوية( الثابت والمتغير البحث الخاص )انتاج واقع الهوية االختالفي باعتماد توازي تأثير التكنولوجيا والتاريخ (( يوضح محور 2-1شكل ) 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 . تاريخية الهوية المعمارية وروح العصر 1.1 اذا ما تغيرت تغير االمر الىى غيىره وهىذا يوضىح ان تعني الهوية الصفات الجوهرية المتفردة المر ما والتي والمتغيىىرات العارضىىة او الحىىاالت الظرفيىىة فبحىىث موضىىوع الهويىىة يعنىىي اننىىا الهويىىة ال تعنىىي الظىىواهر العىىابرة ات الجوهريىة قىد تظهىر لهىا تعبيىرات متعىددة أو نبحث في الجوهر أو الصفات الجوهرية ال االعراض وهذه الصف ( . كما ان الهوية تطلىق كصىفة موضىوعية مىن موضىوعات الفكىر اذا 37متغيرة دون تغير االصل .)رزوقي، ص كان رغم اختالفهما في الزمان والمكان متشابهين في كيفيات واحىدة وتسىمى بالهويىة الكيفيىة أو النوعيىة.)المالكي، لهوية بالرغبة في التعبير عن روح العصر ففي كل حقبىة تاريخيىة يقىوم بعىض األشىخاص (. يرتبط مفهوم ا23ص بإبراز عنصر من هويتهم على حساب العناصر األخرى وعليه فان مسألة صناعة الهوية هىي مسىألة وقتيىة أي إن ا التصور ربمىا الهوية ظاهرة تتشكل باستمرار وكل وقت هناك درجة من الهوية تختلف عن سابقتها والحقتها وهذ يتعارض مع الذهنية التقليدية التي تتطلع إلىى هويىة ثابتىة هىذه الذهنيىة الغالبىة علىى نمىط التفكيىر تحتىاج إلىى إعىادة التفكير بالمتغيرات المتسارعة التي يعيشها العالم والتي البد لها من أن تسىاهم بشىكل جىوهري فىي صىناعة الهويىة ه وجىىودا ثابتىىا ومىىا ينطبىىق علىىى الىىنص األدبىىي ينطبىىق علىىى العمىىل فىىالنص يىىدرك فىىي صىىيرورته ولىىيس باعتبىىار المعماري الذي ال يمكن تفسيره واستخالص معان مختلفة منه بىاختالف المتلقىي وبىاختالف معطيىات الىزمن الىذي فالهوية إذاً ال تتكون نتيجة الرغبة في العيش والبناء المشترك ولكن نتيجة للعىيش فىي ظىل وضىع يرى فيه المبنى موضوعي أنشأه التاريخ ولوجود عوامل موضوعية عديدة سابقة فرضت نفسها على الرغبة فىي العىيش المشىترك وشكلت خصوصية اجتماعية لمجموعة من البشر وكونىت وطىورت ثقافىات وتقاليىد وعىادات وأنشىأت لغىة خاصىة از حضىاري ووسىيلة تعبيريىة (. إن العمىارة إفىر003بها لتفصل بشكل حاسم بينها وبين األمم اآلخرى.)النعيم، ص صىىادقة عىىن ماهيىىة ومسىىتوى تطىىور األمىىم والشىىعوب فقىىد أشىىار )مىىيس فانىىدروه( إلىىى كىىون العمىىارة )آداة العصىىر المترجمة الى فضاء( وهي مرادفة لمقولة كثيراً ما يتشبه بها محلياً مفادها ان العمارة مرآة الحضىارة علىى اعتبىار ة فيترك كل منهما بصماته على االخىر، فالعمىارة أينمىا وجىدت تتماشىى وجود عالقة حوارية مع العصر والحضار مىىع معطيىىات البشىىر فالمكىىان وحضىىارته وتاريخىىه تمثىىل الىىنص الىىذي تكتبىىه باإلضىىافة إلىىى المتطلبىىات والمفىىاهيم (. ويىذكر )بونتىا( ان أي شىكل يمكنىه التعبيىر ونقىل المعلومىة حىال ادراكىه حتىى 2واألفكار المستعملة .)عبود، ص ألشكال المعمارية والفنية التي يراد لها ان تكون محايدة او خاليىة مىن المعنىى حسىب ادعىاء مصىمميها لتعبىر عىن ا الحيىىاة ولتنقىىل رسىىالة معنويىىة رمزيىىة مهمىىة وواضىىحة تجسىىد الفكىىر الىىذي انتجهىىا الواقىىع الثقىىافي واالجتمىىاعي جىدها بسىياق يمتلىك اشىارات تعبىر عىن هويىة واالقتصادي الذي تنتمي اليه اضافة الى المعنى الذي تضيقه عند توا .(33-31معينة او خصوصية مجتمعية معينة فتجردها يكسب سياقها معنى اخر.)بونتا،ص تطرح الهوية كمتغير مرتبط بروح العصر من خالل الظواهر المختلفة والتي تحيط بجىوهر السىمات المكونىة لهىا كونهىا تسىاهم فىي التعبيىر عىن روح فة موضوعية للفكر تتشابه في كل االزمىان واالمىاكن بالصىفة الكيفيىة لهىاكص العصر حيث تبرز عناصرها على حساب العناصىر االخىرى لتشىكل تظىاهرة باسىتمرار بصىيغة تختلىف مىن زمىن صىاعد لالمىام منىتقالً فىي اشىكال الخر، فالهوية كنتاج تاريخي وجغرافي تميىل ليكىون التىاريخ اتجاههىا العمىودي ال اجتماعية وثقافية عدة فيما يكون االثر الجغرافي اتجاههىا وامتىدادها االفقىي باعتمىاد االسىهامات المحليىة والعالميىة لتكون المحصلة وضع موضوعي ينشىأه التىاريخ ضىمن اطىار الخصوصىية االجتماعيىة وهنىا فىاي شىكل يمكىن ان مهىىم فىىي صىىناعة الهويىىة ونقىىل الرسىىالة المعنويىىة تاريخيىىاً وضىىمن سىىياقات يعبىىر او ينقىىل معلومىىة سىىيكون عنصىىر متعددة. . التكنولوجيا وروح العصر0.2 لقد تزايدت اهمية التكنولوجيا في عالمنا المعاصر بسبب دورها الواضح والمؤثر في مجمىل النتاجىات الذهنيىة تطىور التكنولىوجي وزيىادة القىدرات التكنولوجيىة التىي والفيزياوية لالنسان في عصرنا الىراهن الىذي يمثىل ذروة ال رافقت االنسان عبر تاريخه الطويل فهي قديمة قدم االنسان اال ان الشيء الوحيد الحديث هذا الموضىوع هىو اللفى ذاته وبذلك فهي تحتف بسمتها الرئيسية باعتبارها نشاطاً انسانياً يهدف ايضاً الى بلوغ غايات االنسىان وتىدخل فىي بنىىى واظهىىار كافىىة الظىىواهر االنسىىانية التىىي تشىىكل بىىدورها تىىاريخ وحضىىارة االنسىىان فىىي عالمىىه المعاش.)زكريىىا، (. وبالرغم من إدراك وفهم المعطيات التكنولوجية ضمن إطىار البيئىة المتغيىرة فىي العمىارة إال أنهىا تميىل 072ص ديثىة علىى العلىم والحقىائق العلميىة الثابتىة وكىذلك في الوقت الراهن إلى الثبات وذلك نتيجىة اعتمىاد التكنولوجيىا الح الحال بالنسبة للفكر اإلنساني فالعالم موحد إذا نظرنا إليه من زاويىة معينىة ولكنىه متعىدد إذا نظرنىا إليىه مىن زاويىة (. ان العمارة والتكنولوجيا تمثالن انظمة توالديىة 02أخرى وعليه فهو متعدد وواحد في الوقت نفسه.)المنشدي،ص ات طبيعة تواصلية هذا من جهة ومن جهة اخرى ان هذا العالقىة بىين العمىارة والتكنولوجيىا تسىاعد علىى دراسىة ذ التطور الفكري للعمارة وبذلك يستنتج ان العمىارة مالزمىة للتكنولوجيىا اذ ان العمىارة تعتمىدها مرتكىزاً اساسىياً فىي 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 (. ان حضىىىور 021-030مىىىارة ايضىىىا.)العلي، صتعاريفهىىىا وان تواصىىىلية التكنولوجيىىىا تىىىوافر تواصىىىلية فىىىي الع التكنولوجيا في الفكر المعماري يىؤدي الىى التطىور فىي عقليىة االنسىان وذلىك نظىرا للتىراكم المعرفىي الىذي تحدثىه (. هىذا 022التكنولوجيا فتتحىول هىذه العقليىة مىن عقليىة احاديىة البعىد الىى عقليىة مركبىة متعىددة االبعاد.)جميىل،ص لوجيا وباعتمادها على الفكر تقوم باسقاط مفهوم انساني )اسواء كان فيزياوياً او غير فيزياوياً( فضالً عن ان التكنو على االشياء التي نتعامل معها وتضيف اليه ابعاد فكرية واخالقية واستيطيقية لذاك فان التكنولوجيا هي ليست فقط فضالً عن الفعل الجهود الفكرية التي تسهم في انتاج النواتج النهائية او العمليات التي تقوم بانتاجها بل هي تتضمن الفعىىىل التكنولىىىوجي وتقىىىوده وتتحىىىاور معىىىه بحيىىىث باالمكىىىان القىىىول ان فكىىىر التكنولوجيىىىا هىىىو تعبيىىىر عىىىن الفكىىىر كمىا يىرى )هيغىل( أن العمىارة ال يمكىن دراسىتها بمعىزل عىن سىياقها الحضىاري .beallne, p202)الحضىاري.) ه يكيىف العىىالم الخىارجي ويكتسىىب بىذلك مىىا يسىمى النظىىرة العالميىة والتىىي تكمىن فىىي فالمعمىاري ومىىن خىالل فكرتىى التكوين الواعي والالوعي للعقل البشري والمعماري ليعبر عن فكرتىه بهيئىة ماديىة محسوسىة متىأثرة بعىدة عوامىل عصىرنا الحىالي وهي السياق الحضاري وروح العصر والنظرة العالمية ، ويرى )هيغل( أيضاً بأننا ال نمثىل روح فقىىط وإنمىىا روح جميىىع عصىىورنا الماضىىية وأن التىىاريخ يعمىىل كرابطىىة تطوريىىة مسىىتمرة ومتواصىىلة تىىربط جميىىع (. ويىذكر nesbitt, p96 – 99األشىياء فىي كىل متجىانس وهىو بىذلك يشىيد بأهميىة التواصىل ودوره فىي التىاريخ.) ان تسىتحق اسىم العمىارة بجىدارة مىا لىم تكىن مترجمىة )بونتا( مقولة )ميس( التي ذكىر فيهىا ال يمكىن البنيتنىا النفعيىة (. ويىىىىىىرى )ريتشىىىىىىارد روجىىىىىىرز( ان المبىىىىىىاني فىىىىىىي كىىىىىىل عصىىىىىىر قىىىىىىد احتفىىىىىىت 23لعصىىىىىىره. )بونتىىىىىىا،ص (. لكنه ال ينتقد فكرة الرجوع الى الماضي بصورة مطلقة كما كانت الحداثة تفعل بل ينتقد rogers,p.36بتقانتها.) ( .ويضىيف rogers, p82ل مىن تراثنىا المعمىاري مىا يخنىق مسىتقبلنا(.)سوء التصرف بالماضي قائال )اليوم نجع مفسراً )اذا تعاملنا مع الحلم التاريخي للماضي الذي لم يعد موجوداً بدالً مىن اسىتخدام العقىول واالدوات المعاصىرة عي( لىذا فهىو فان مستقبلنا سيكون اجرد على اقل تقدير فالمفروض هو استخدام الماضي )الحلم( ال الماضي )الىواق يؤمن بالحفاظ والتعلم من التاريخ لكن استنساخ التاريخ يقلىل مىن قيمتىه مستشىهداً بالمعمىاري )فىولر( رائىد التعامىل البيئىي والتكنولىوجي الىذي يىذكر بىان االمىل بالمسىتقبل متجىىذر فىي ذاكىرة الماضىي فىبال ذاكىرة ال يوجىد تىىاريخ وال (. rogers, p9-10في المستقبل( .)معرفة وبالفهم الصحيح للماضي يكمن االمل تتعامل التكنولوجيا مع تكوين دور واضح ومؤثر في النتاج الذهني والمادي لالنسان ضمن العصر الراهن والذي يطىىرح تطىىوراً هائىىل فىىي القىىدرات التكنولوجيىىة عبىىر االزمىىان وتىىدخل فىىي بنيىىه كافىىة الظىىواهر االنسىىانية المشىىكلة تغيىىرة فىىي العمىىارة ، فالعمىىارة والتكنولوجيىىا مترابطتىىان وتتواصىىالن باعتمادهمىىا للحضىىارة ضىىمن اطىىار البيئىىة الم مرتكزاً اساسياً لبعضهما البعض كما وتسقط التكنولوجيا مفهوم انساني علىى االشىياء التىي تتعامىل معهىا باعتمادهىا لفكىر الحضىاري مىن على الفكر وتضيف لها ابعاد فكريىة واخالقيىة وصىوالً لطىرح فكىر التكنولوجيىا كتعبيىر عىن ا خالل تضمينها بعدي الزمان والمكان لربط العمارة بالتكنولجيا بروح كل عصر وكل مكان. -مناقشة )المحور البحثي(: ترتبط الهوية تاريخياً بروح العصر من خالل عدة ظىواهر وتعمىل كصىيغة موضىوعية للفكىر تتشىابه فىي كىل التعبير عن روح العصر بابراز عناصرها على حساب االخرى وهنىا زمن و مكان بالصفة الكيفية لها وتساهم في فالتاريخ هو االتجاه العمودي الصاعد فيمىا االثىر الجغرافىي هىو االمتىداد االفقىي لىروح العصىر ضىمن خصوصىية اجتماعية تساهم في صناعة هويتهىا امىا التكنولوجيىا فهىي تكىون دور واضىح فىي النتىاج الىذهني والمىادي لالنسىان العصر الراهن من خالل طرح قدرات متطورة عبر االزمان مع اعتماد واضح للفكر وتصنيف ابعاد فكرية ضمن وممىا سىبق يتوضىح دور وعالقىة كىل مىن التىاريخ والهويىة بىروح العصىر واخالقية معبرة عىن الفكىر الحضىاري. والمادية مىع الفكىر الحضىاري فىي كاتجاه عمودي صاعد والتكنولوجيا المتوازية تطورا بقدراتها ونتاجاتها الذهنية اعتماد االبعاد الفكرية واالخالقية العامة . -وهذا ما سيقود البحث لطرح محوره البحثي وكاالتي: الهوية مركب حضاري اثر التاريخ كاتجاه عمودي صاعد تطوير القدرات ذهنيا اثر التكنولوجيا التطوري وماديا الناتج النهائي استمرار التاثير تاثير روح العصر تاثير روح العصر ( يوضح المحور البحثي )اثر روح العصر على الهوية كمركب حضاري باعتماد 3-1شكل ) مؤشرات التاريخ والتكنولوجيا التفصيلية( 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 -وهنا سيتم عرض مشكلة البحث المعرفية مما سبق وكاالتي: المعرفي الخاص بتعريف واقع الهويىة االختالفىي باعتمىاد عالقىة التكنلوجيىا والتىاريخ فىي " عدم وضوح التصور العمارة ". اما عن هدف البحث فيطرح كاألتي: " توضيح التصور المعرفي الخاص بتعريف واقع الهوية االختالفي باعتماد عالقة التكنلوجيا والتاريخ في العمارة ." الخطوات االتية:وان منهج البحث يمكن طرحه في  بناء اطار معرفي يتكون من اطار نظري يتم فيه استعراض الجوانب المرتبطىة بتعريىف واقىع الهوية االختالفي باعتماد عالقة التكنلوجيا والتاريخ في العمارة.  .طرح نماذج معرفية وتطبيقيه تمثل اطار ومادة للقياس الجراء التطبيق  صىة بتعريىىف واقىع الهويىة االختالفىي باعتمىاد عالقىىة توضىيح واستكشىاف حىاالت التحقىق الخا التكنلوجيا والتاريخ في العمارة. .المحور الثاني: االطار المعرفي. 2 . بناء االطار النظري2.1 سىىيتم هنىىا طىىرح المعرفىىة المتخصصىىة عىىن الجوانىىب المرتبطىىة بتعريىىف واقىىع الهويىىة االختالفىىي باعتمىىاد عالقىىة خىالل التركيىز علىى الطروحىات المعرفيىة اجمىاالً لحركىات معماريىة متنوعىة ومتسلسىلة التكنولوجيا والتاريخ مىن مثلت مراحل واضحة ومهمة في اطار تطور الواقع النظري للعمارة والجانب العلمي لظهور الجوانب الثقافية فىي لنظريىىة وعالقتهىىا المراحىىل التاريخيىىة المختلفىىة. وقىىد شىىمل الطىىرح فىىي ثنايىىاه الرؤيىىة العامىىة للجوانىىب الخاصىىة با بالمبىىادا العامىىة فىىي العمىىارة وهىىذا مىىا شىىمل رؤيىىة كىىل حركىىة ومرحلىىة ألثىىر المتغيىىران السىىابقان ) التكنولوجيىىا -وكاالتي: والتاريخ( . العمارة الكالسيكية لعصر النهضة2.1.1 يمه الثقافية مشىتقة مىن اعتمدت النظرية فيها على محاكاة الطبيعة فاالنسان مكون من طبيعة محايدة قابلة للتعلم وق الطبيعة وبذلك فاالفضلية للعمارة كتصميم كانت تلك القريبة مىن الطبيعىة والعمىارة القريبىة مىن الطبيعىة توجىد فىي ابنية الفترة الماضية في الغرب وفي )طرز االغريقية والرومانية( حتى فىي الكالسىيكية الجديىدة وعلىى الىرغم مىن نهضة فان تحديدها للقوانين الثابتىة )بمحاكىاة الثبىوت فىي الطبيعىة ولىيس الطبيعىة اختالفها عن الكالسيكية لعصر ال نفسىىها( والمعتمىىدة علىىى تركيىىب كىىل مىىن االصىىالة وقىىانون الطبيعىىة والعقىىل فنىىرى ان اصىىل العقىىل فيهىىا ارتىىبط مىىع (.22، ص العمارة التي تعكس هذه القوانين وفي الكالسيكية القديمة ايضاً االغريقية الرومانية .)مردان عمارة القرن الثامن والتاسع عشر .2.1.2 شهدت تغير النظرة مىن ثبوتيىة قىوانين الطبيعىة الىى مفىاهيم السىيرورة النسىبية لتطىور التىاريخ فاالنسىان ومقاماتىه االجتماعية يمكن ان تفهم فقط ضمن السياق الذي تتطور ضمنه فهي محكومة بقوانين توالدية حيويىة وليسىت ثابتىة فالمثالية كانت الهدف الذي انبثق من التجارب التاريخية واالحتمالية وقد يظهر من يطالب بالمثالية المتشابهة ابدية لكل الحضارات لكنها لن تدرك عقالنيىاً فكىل ثقافىة تمتلىك خليطىاً مىن الوضىوح والغمىوض بالنسىبة للمثىالي ولكنهىا لقيم التي تكىون متضىمنة فىي المجتمىع مىن خىالل تحتف بمفهومها الخاص عن صدق وكذب ذلك المثال من خالل ا مقاماتىه فىىان المجتمىىع هكىىذا ال يمكىىن ان يفهىم باالسىىلوب الىىذي يلغىىي ذاتيتىىه او ان يىدرس علىىى اسىىاس قىىوانين قبليىىة فاعتبر هدف المؤرخين هو دراسة المجتمع الجل المجتمع وليس الثبات مبادا قبلية وكانت لهىذه النظىرة المهيمنىة اها فىىي العمىىارة فىىالنظرة )المجتمىىع الجىىل المجتمىىع( طرحىىت مفهىىوم النسىىبية الثقافيىىة الن المثىىالي علىىى التقليىىد صىىد سيختلف من حالة الى اخرى ومن مجتمع الى آخر فترجمت الحركة الرومانسية هذه الى مواقف بفعىل )االنتقائيىة( (.22من طراز تاريخية متنوعة في الفن والعمارة.)مردان، ص حداثةعمارة ال .2.1.1 رفضت الحداثة كل اشكال اعادة االعتبار لطرز الماضي واعتبارها عناصر زخرفية خادعة ودعوتها الى الىوعي الى اللحظة الحاضرة كلحظة تاريخية منفصلة والعمارة تظهر مخلصة للتاريخ بادارة ظهرها عىن التقاليىد والنظىر طىىع الجىىذري مىىع الماضىىي وذلىىك تحىىت تىىأثير التطىىور باتجىىاه المسىىتقبل ففكىىر الىىرواد الطليعىىة كىىان مبنيىىاً علىىى الق (banham)و (pevesher)و (giedion)التكنولىىوجي واالجتمىىاعي للحاضىىر فكىىل مىىن مىىؤرخي الحداثىىة مثىىل عملىىوا علىىى التأكيىىد علىىى الهيئىىة التطوريىىة للحركىىة ومىىع ذلىىك كىىان للحداثىىة موقفهىىا المحىىدد مىىن الطىىرز التاريخيىىة فظهرت الفكرة بأن االساءة الى الطرز جاءت بتأثير مبادا االحيائية التي قللت من قيمة الطراز وبىدا التاكيىد علىى الحركة الحديثة الطراز بأنه اطار ما للنمو الكامن بدل تقاليد خاصة في المحاكاة والمعالجة لطرز الماضي فعرفت من المثال الثابت الذي تطابقه الظواهر التاريخيىة فىدرس الطىراز عمليىاً ولىيس اعتمىادا علىى مبىدأ المحاكىاة بحيىث 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 يصبح من الممكن مضاهاة الطرز العظيمة في ماهيتهىا كمجىال معرفىي عىام للمنشىأ والتصىميم بلغىة ذلىك الحاضىر اولت معالجة نظام التمثيىل المىوروث مىن عصىر مىا قبىل الصىناعة والىذي لىم يعىد يتماشىى مىع التغييىرات وبذلك ح (.27السريعة.)مردان، ص عمارة ما بعد الحداثة .2.1.2 اعتمدت الحركة الحديثة في توسىيع مفاهيمهىا ونشىرها مىابين المعمىاريين علىى صىيغة المعتقىد وااليمىان بالمبىادا مفهومىاً آخىر لتوسىيع (wittgenstein)النصف االول من القرن العشرين بعد ذلك قدم الفيلسىوف التي يقدمها في مبىىادا الحركىىة فبىىين ان الحركىىة تمتلىىك مىىن التعقيىىد مىىا يجعلهىىا صىىعبة التعريىىف فهىىي للمصىىنفين تظهىىر كمنغلقىىات اميع متراكبىىة اعشىاش الطيىىور علىىى شىجرة واحىىدة بتركيىىب العديىد مىىن الخصىىائص والميىزات الىىى كىىل او هىي مجىى لعوائل من المتشابهات عالمياً وجزئياً وبتحكيم استطيقي يعود للفرد وارتبط هذا التعريف للحركة مىع ظهىور فكىرة طىىرز العمىىارة التاريخيىىة كمىىؤثر فىىي الحركىىات لمىىا بعىىد الحداثىىة والىىذي تسىىلل مىىع الظهىىور المباشىىر السىىاخر الىىى والنجاح التجاري لالسلوب العىالمي فىي الخمسىينات بىدأ وعىي الضمني الشعري فمن خالل دورات النقد المستمرة المعماريين والمصممين لتأثيراته الحضرية وفقر الداللة الثقافية نتيجة لفشل ابنية ومساكن الحداثيون فىي االرتبىاط المبنىى مع السياق او مع الشفرات او الرموز التي يفهمها مستعملوا المبنى اي انه في حركة الحداثة جاءت رموز لما يفهمه المصىممون ولىيس العامىة فبىدأت نظريىة العمىارة ببحىث المعنىى فىي العمىارة مىن خىالل المماثلىة اللغويىة بالمقارنة مع العمليات اللغوية فأعتمدت مابعد الحداثة على العمىارة التاريخيىة فىي المعالجىات الشىكلية وبمسىتويات نتقائية الراديكالية وتعددية الشفرة والمنطق المزدوج .مختلفة اال انها في كل منها كانت معتمدة على اال وقىىد شىىملت المجموعىىة االولىىى لمعمىىاري مابعىىد الحداثىىة تحىىت تصىىنيف التاريخيىىة والتىىي ضىىمت معمىىاريين حىىداثيون واعىىين لمشىىكلة الحداثىىة لكىىنهم غيىىر متىىدربين تاريخيىىاً للتعامىىل مىىع التقليىىدي كحىىديث فكىىان مىىن الصىىعب ات التاريخية بصورة ايجابية لتالئم مبانيهم فالموقف من التاريخ كان متحكماً وساخراً واالسىتعارة استخدام المؤشر التاريخية جاءت بصورة اعتباطية ومن اي فترة تاريخية طرازية كقطع مضافة للخلق الجديد . وبذلك فسىحو المجىال السىتعمال اما المعماريين في تيار االحيائية المباشرة بدأوا اعمالهم بممارسة االحيائية االشكال التاريخية بصورة اكثر حرفية ويمكن مقاربة عملهم مع االحيائيىة الغوطيىة التىي ظهىرت فىي بريطايىا فىي القرن السادس عشر والسابع عشر والثامن عشر اي ان تاكيدها جاء عنه تقاليد مايسمى الطراز الوطني او القومي دة منها المستوى الذي قدمه )الدوروسي( والذي ارتبط مع مفاهيم مثل احيىاء مابعىد فاالحيائية هنا على مستويات ع الموت والذاكرة التاريخية واعادة صور المدينة والتي تعبىر مىن اهىم مصىطلحات مابعىد الحداثىة فىي تأكيىدها علىى ترجمىىىة الجمعيىىىة وحقىىىل العامىىىة اال ان اعمىىىالهم عىىىادة مىىىا انتهىىىت بتىىىأثيرات نصىىىبية بسىىىبب عىىىدم الوضىىىوح فىىىي (.22-23الرمز.)مردان، ص بناء النماذج المعرفية . 2.2 سيتم التوجىه نحىو تبنىي نمىوذجين معىرفيين عىامين مىن حقىل العمىارة مىع اعتمىاد الواقىع االختالفىي للهويىة المتىأثر ابقين فىي بعناصر كلمن التكنولوجيا والتاريخ لتأشير اطار عام ومادة للقياس باعتماد عالقة التىرابط للمتغيىرين السى مشكلة البحث ولتقييم الطرح في االطار النظري. وذلك بتبني كىل مىن نمىوذجي ) الحركىة والطىراز( فىي العمىارة ودراسة العالقة الترابطيىة بينهمىا فىي تعريىف مالمىح االخىر ضىمن اطىار العمىارة والتعريىف العىام للحالىة الثقافيىة وسيتم ذلك على عىدة لوجيا والتاريخ وتعريف كل منهما لالخر.المطروحة للتعبير عن العالقة الترابطية بين التكنو عوامل ستختص االولى بالطرح النظري العام وعن كل منهما والثانية وبتوضيح تعريف كىل منهمىا لالخىر ضىمن اطار العمارة وتعريف الحالة الثقافية المطروحة استناداً لطروحات معماريىة متخصصىة تناولىت الموضىوع وهىي احثة )تارا عبد الرزاق علي مردان(.طروحات الب المرحلة االولى: الطرح النظري العام. . 2.2.1 الحركة والطراز . 2.2.1.1 هو اسلوب ابداع ادبي وفني او هىو صىيغة التعبيىر عىن الفكىر بلغىة متكوبىة اوشىفهية. اوسىلوك او طريقىة الطراز: للفعل اوهيئة مميزة بمقاييس ناتجة اما عن قانون او عرف وتعزى الىى جماعىة او فتىرة معينىة وهىو الطريقىة التىي و الطريقىىة اسىىتعمال الشىىي المشىىابهة يكتىىب بهىىا الشىىخص او يتعىىرف والحالىىة النوعيىىة الجيىىدة للمظهىىر واخيىىراً فهىى (.0لطريقة استعمال اللغة بصيغة محددة مسبقاُ .)مردان، ص الفعل او الضرورة لتغيير المكان او الوضعية او هي التقىدم باتجىاه خىاص نحىو موضىوعية خاصىة وتىرد الحركة: كىة سىريعة الحركىة او كخاصية وميزة تظهر في اي نص بحيث يصبح مثير ونابض بالحياة مىن خىالل امتالكىه حب غىىزارة ووفىىرة فىىي االحىىداث والوقىىائع المثيىىرة او امتالكىىه السىىلوب محىىاكي سىىلس وحيىىوي يىىرتبط مىىع االهتمامىىات الثابتة للمتلقي واخيراً فهي فعل التغيير وتتمثل الحركة في االتجاهىات السياسىية واالجتماعيىة والثقافيىة ومنهىا الفىن ة وانما محفزة بقوة معينة وهي بذاتها قوة بسبب التغيير الذي توجىده الىى ان والعمارة. وهي ال تظهر بصورة تلقائي تتحول الى فعل يعتمد االصل في الحركىات علىى مىا يظهىر كتصىنيف اساسىي للمرحلىة بتىأثير التطىورات فىي احىد فعىل النقديىة. الجوانب الثقافية مما يجعلها عرضة للتغيير المستمر اما بسىبب االكتشىافات الجديىدة او بسىبب ردود ال كما ان اعتمادها على الموائمة ما بين عده معماريين يحوي نوع من الذاتية الذي بىدوره يخلىق نىوع مىن االخىتالف 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 -3في درجات الوالء واالخالص للحركة وال يعطيها امكانية ان تمثل كامل نتاج المرحلىة المعماريىة.)مردان، ص 22.) ل نمووذج علوى تعريوف االضور اومن اطوار العموارة وتعريوف المرحلة الثانية: التعريف الثنائي الثر ك .2.2.2 الحالة الثقافية المطروحة. ان تعيين الى مرحلة تاريخية او معاصرة مستقلة معمارياً على اساس تعريفها كطراز معماري او حركة معماريىة يعتمد على اآلتي: ت المعمارية فيها كحتميىة بمفىردات لغىة يظهر الطراز في الفترات التي يطفئ فيها تأثير الثقافة وتظهر النتاجا -0 متداولة ومقىررة مسىبقاً، بحيىث تىرى الثقافىة نفسىها فىي عمارتهىا وتكىون العمىارة فيهىا اثىراً ولىيس نتيجىة بنىاء (. 1-0فكري مستقل.شكل رقم ) تبنىىى الحركىىىات المعماريىىىة علىىىى اسىىىاس صىىىيرورة عمليىىة مىىىن خىىىالل تغييىىىر مفهىىىوم دور الفىىىرد المصىىىمم ) -3 امتالكه حرية التدخل الثقافي وتصبح الحركات ممكنة التعيين باتفاق مجموعىة مىن االفىراد علىى المعماري( و مبادئها االساسية وفي الحركات تكون التحديىدات مرتبطىة بنظىام معرفىي يتحىدد مىن قبىل المعمىاريين انفسىهم. (.2-0شكل رقم ) بينما يىرتبط التىأثر بىالطراز مىن خىالل يتأثر التصميم المعماري المعاصر بشكل اساسي بالحركات المعمارية -2 (.13ظهور حركات معمارية معاصرة تبنى على مرجعية مفاهيمية او شكلية لطرز تاريخية.)مردان، ص تأثير الثقافة االحتمالي العمارة ظهور الحركة ( يوضح ظهور الحركات5-1شكل) اتفاق االفراد المصممي اتفاق االفراد المصممي حرية اكبر للفرد المصمم حرية اكبر للفرد المصمم دور الفرد المصمم دور الفرد المصمم تأثير الثقافة الحتمي ظهور الطراز العمارة أثر للثقافة العمارة ( يوضح ظهور الطرز4-1شكل) 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 التطبيق 2.3. سيتم تطبيق االطار النظري بمؤشراته وطروحاته العامة كطرح معماري متخصص للحركىات والطىرز المختلفة على النماذج المعرفية المتبناة والمتمثلة بمفهومي الحركة والطراز في العمارة وعلى خطوات حيث سىيتم ع المتغيىىرات االساسىىية للبحىىث )التكنولوجيىىا فىىي الخطىىوة االولىىى التطبيىىق بمماثلىىة النمىىاذج المعرفيىىة المتبنىىاة مىى والتاريخ( وفي الخطوة الثانية سيتم تطبيق النماذج المعرفية على االطار النظري وفي الخطىوة الثالثىة سىيتم عكىس ما تم التوصل اليه في الخطوة الثانية على متغيرات البحث االساسية سالفة الذكر وفي الخطوه الرابعه سيتم تطبيق ق من نماذج المعرفية متبناة ومتغيىرات اساسىيه علىى عينىه منتخبىه للتطبيىق تتمثىل بمشىروع مكتبىه سىان كل ما سب فرانسيسكو العامه. وقبل كل ذلك سيتم طرح التصىورات االفتراضىية عىن طبيعىة الحىاالت الناتجىة بحسىب اعتمىاد الهياكل للنماذج المعرفية والطروحات في االطار النظري وكاآلتي: -التصورات االفتراضية العامة: تماثل اثر طرفي ثاايةيم مترةير اث ايس ايااايةات ناثتجااثااةيا ااثتيارةثر ميف اثير طرفي طرفي .1 ثاايةم اثاماذج اثمعرف ناثارجم ااثطرازر. ةتاقييو ااييار رار ثيتييارةث فيي تااييةال اثاا ييف اي تيفيي ثيةاةييم فيي اثعمييار اثجياييةجةم ثع يير .2 اثاةضم . رار ثيتارةث ف تااةال اثاا ف اي تيفي ثيةاةيم في رميار اثقيرت اثثيامت ااثتاايف ةتاقو ااار .3 رشر. ةتاقو ااار رار ثيتارةث ف تااةال اثاا ف اي تيف ثيةاةم ف رمار اثاراثم. .4 ةتاقو ااار رار ثيتارةث ف تااةال اثاا ف اي تيف ثيةاةم ف رمار ما عر اثاراثم. .5 ث ااثتجايااةا ف تاايةال اثاا يف اي تيفي ثيةاةيم في اثاتياج اثمعميار ةتاقو ااار رار ثيتارة .6 اثمعا ر. -التصورات االفتراضية الثانوية: -2 ةتاقو ظةار اثطراز نجاماذج معرف ر ف اثعمار اثجياةجةم ثع ر اثاةضم. .1 ةتاقو ظةار اثطراز نجاماذج معرف ر ف رمار اثقرت اثثامت ااثتااف رشر .2 ثطراز ف اثاماذج معرف ف رمار اثاراثم.ةتاقو ظةار ا .3 ةتاقو ظةار اثطراز نجاماذج معرف ر ف رمار عر اثاراثم. .4 الخطوة التطبيقية االولى: مماثلة النماذج المعرفية مع متغيرات البحث االساسية . 2.3.2 ةتاضييم مييت اثطييرب اثاييا و ثجييل مييت مترةييراة اث اييس اياااييةم ناثتجااثااةييا ااثتييارةثر فةمييا ة ييت تااييةال اا ييف ا تيفيي ثيةاةييم فيي اثعمييار ارتمييار جييل مييت اثلعييل اياايياا ااثمييار ثيتجااثااةييا اارتمييار ري ييم اثثا يية ااثمترةيير جاتياج ا ييةم معا يير تاميل ييلم اثلررةييم ثيتيارةث جاييل تشييجةل راةيم رامييم ت يي اثةاةيم اثمعمارةييم تطييار ااثترةييير ميييت ييييل رةمامتةيييا ااايييتمرارةتةا ر ييير اثيييزمت. ا اثمقا يييل ةاايييال اثطيييرب اثاظييير ايييال اثطيييراز جطرةقيييم ااتعمال ثألشةاء اا اثيرم اثمارر ااثارجم اثممثييم ثلعيل اثترةير ثألفجيار ااثملياظةو اظةيار ذثيم شيجل ماليز قيا ي يير فييات اثطييرب اث ييا ظةييار اثطييرز فيي اثلتييراة اثتيي ةطريي فةةييا تيياثةر اثثقافييم اايير معةاييم. امييت اثااايي ا اثعمار تاثر ثيثقافيم اةيس تظةير اثاتااياة جاتمةيم مليرراة ثريم مترااثيم امقيرر ماي قاح ا اياء اثارجياة اثمعمارةيم . ري اااال ةرار رميةم ترةر رار اثلرر اثم مو اامتيجه ارةم اثتر ل اثثقاف -مت جل ماا و تاضةم ايت : 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 اع اثتجااثااةا ااثتارةث ثتااةال اا ف ا تيف ثيةاةم ارتمار راا ر مارر . .1 اع اثارجم ااثطراز ثيتاثةر ف اثااثم اثثقافةم اثمطراام ارتمار راا ر مارر . .2 ارجم اثممتيم ثلعيل اثترةير في تماثل اثر ارةاامةجةم جل مت اثتجااثااةا اثمعتمر اثلعل اياااا ااثمار مف اث .3 اثتاثةر اثعاو. تماثل اثر ارةاامةجةم جل مت اثتارةث اثمعتمر اثثا ة ااثمترةر مف اثطراز اثممثل ثمايار اايتعمال ايشيةاء في .4 اثتاثةر اثعاو. اضياب اثااثيم اثترا طةيم اثااتايم يةت طرفي جيل ثاايةيم ممييا اي و في اثتياثةر اثعياو اظيا ميا ايةعتمر ياقياح فيي .5 .اث طااة اثتط ةقةم اثمق يم اياتعاضم رت طرو جل ثاايةم اثطرف اي ر ف اثثاايةم اي ر الخطوة التطبيقية الثانية : تطبيق النماذج المعرفية على االطار النظري. .2.3.2 تطيييرب ظايييا اييياية متعيييرر ثيتط ةيييو ااييي جيييل رميييار اطراةيييا اثاظييير اثمايييتقل ميييا ةيييييو اثتاايييه ج امييياذج -معرف ثذا اةار تاضةم اثتط ةو ري مراال رر اجايت : الحالة التطبيقية االولى )العمارة الكالسيكية لعصر النهضة(. أ تاضييةم ثااثييم ظةييار جييل مييت اميياذا اثارجييم اا ةتاضييم ظاييا ا اايي مييا طييرب فيي فقيير اثاميياذج اثمعرفةييم مييت اثطييراز اايي ييا اثتيياثةر فيي اثااثييم اثثقافةييم اثمطرااييم ااتمةييم اا ااتماثةييم اثاتيياج امقييرار ارةييم اثم ييمو فيي تشجةل اثاتاج افو اثم ارئ اثمارر ا اثاظر ثترجةز اثطرب اثاظر رت ااثم اثعمار اثااثةم ةظةر ات ظذه اثعميار م ظةيار اثطيراز شيجل ا يا ميت جااةيا تيرام ظةيار اثارجيم اذثيم اي ط ةعيم اثتعاميل ميف اثقياااةت تمةل ثتراة اثثا تم مااجا اثث اة ف اثط ةعم. الحالة التطبيقية الثانية )عمارة القرن الثامن والتاسع عشر(. ب ميياذا اثارجييم اا ةتاضييم ظاييا ا اايي مييا طييرب فيي فقيير اثاميياذج اثمعرفةييم مييت تاضييةم ثااثييم ظةييار جييل مييت ا اثطييراز اايي ييا اثتيياثةر فيي اثااثييم اثثقافةييم اثمطرااييم ااتمةييم اا ااتماثةييم اثاتيياج امقييرار ارةييم اثم ييمو فيي تشجةل اثاتاج افو اثم ارئ اثمارر ا اثاظر ثترجةز اثطرب اثاظر رت ااثم اثعمار اثااثةم ةظةر ات ظذه اثعميار ت جااةا ترام ظةار اثارجم اذثم ا تطيار اثاظير ميت اثتعاميل ميف تمةل ثتراةم ظةار اثطراز شجل ا ا م اااةت اثط ةعم اث ملاظةو اث ةرار اثاا ةم ثتطار اثتارةث ارتمار اثاةا اة اياتمارةيم ميف اثترجةيز ريي ملةياو .تا ه اثثقافاة اتشجل طرز متعرر جاتةام ثةا الحالة التطبيقية الثالثة )عمارة الحداثة(. ت اضييم ظاييا ا اايي مييا طييرب فيي فقيير اثاميياذج اثمعرفةييم مييت تاضييةم ثااثييم ظةييار جييل مييت اميياذا اثارجييم اا ةت اثطييراز اايي ييا اثتيياثةر فيي اثااثييم اثثقافةييم اثمطرااييم ااتمةييم اا ااتماثةييم اثاتيياج امقييرار ارةييم اثم ييمو فيي م اثعمار اثااثةم ةظةر ات ظذه اثعميار تشجةل اثاتاج افو اثم ارئ اثمارر ا اثاظر ثترجةز اثطرب اثاظر رت ااث شجل ا ا مت جااةا ترام ظةار اثطراز اذثم ا اثتاجةر ري تقاثةر ا يم في تمةل ثتراةم ظةار اثارجم اثمااجييا ااثمعاثاييم ثيماضيي طييرب تعرةييف اثطييراز ااييه اطييار ثيامييا اثجيياف ييرل مييت اثمثييال اثثا يية اثييذ تطا قييه س ةررال اثطراز رميةاح ةمجت مضاظا اثطرز اثعظةمم جماال معرف راو ثيماشيا ااثت يمةو اثظااظر اثتارة ةم اة يرم اثااضر ثتعاثج اظاو اثتمثةل اثماراس مت ر ر ما ل اث اارم اظاا ةتاضم ااه رغو اثترجةز ري ظةار ااي ثيطيراز ةراري اثارجم ث اثم اضعاف ظةار اثطراز اي ات اثمعاثام اثمطراام ثيطراز تتعامل ميف اظةيار اااره ضمت ظذه اثعمار شجل اا . 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 الحالة التطبيقية الرابعة )عمارة مابعد الحداثة(. ث ةتاضييم ظاييا ا اايي مييا طييرب فيي فقيير اثاميياذج اثمعرفةييم مييت تاضييةم ثااثييم ظةييار جييل مييت اميياذا اثارجييم اا تماثةييم اثاتيياج امقييرار ارةييم اثم ييمو فيي اثطييراز اايي ييا اثتيياثةر فيي اثااثييم اثثقافةييم اثمطرااييم ااتمةييم اا اا تشجةل اثاتاج افو اثم ارئ اثمارر ا اثاظر ثترجةيز اثطيرب اثاظير ريت ااثيم اثعميار ةظةير ات ظيذه اثعميار تمةيل ثمعارثم تراةم ظةار جل مت اثطراز ااثارجم اذثم ا ارتمارظا اث اس رت اثمعا مت يل اثمماثيم اثيراةم ةييياة اثيراةيييم فةييي فييي تاجةيييرظا ريييي اثتارة ةيييم فييي اثمعاثاييياة اثشيييجيةم شيييجل ميييتةجو اايييا ر اثمقارايييم ميييف اثعمي اماتعةر مت اثتارةث ار ارت اطةم ثذا فةاا ظ تاشير جظةيار اثارجيم ارتميار ارةيم اثما يف اثلجير ثيم يمو تياثةراة ا يةم تيار ثعيرو أا ممارام اياةايةم اثم اشر جاتعمال ايشيجال اثتارة ةيم يار اجثير ارفةيم اطيرب اضاب ف ترامم اثرمز ثذا فةاا ظ تاشر اظةار اثطراز ارتمار اثتاثةراة اثاا قم ار م اشر اارفةم. الخطوة التطبيقية الثالثة: )عكس نتائج الخطوة التطبيقة الثانية علىى متغيىرات البحىث .2.3.3 االساسية(. الحالة التطبيقية االولى أ اثااثييم اثتط ةقةييم اثمماثيييم فيي اث طييا اثاييا قم ثظةييار اثطييرز اثاييا قم ثظةييار اثطييراز شييجل ةتاضييم مييت تييراةم ا ا مت اثارجم ف اثعمار اثجياةجةم ثع ر اثاةضم ا اا اثطيرب اثايا و اميت ايراء اثمماثييم اثمعتمير ميف م ثييرار اثتييارةث اثمعتميير مييا تييو فيي اث طييا اثتط ةقةييم اياثيي ةتاضييم تييراةم اثعمييار اثجياييةجةم ثع يير اثاةضيي اثثا ة ااثمترةر ف تااةال اثاا ف اي تيف ثيةاةم ف اثعمار . الحالة التطبيقية الثانية ب ةتاضييم مييت تييراةم اثااثييم اثتط ةقةييم اثمماثيييم فيي اث طييا اثاييا قم ثظةييار اثطييرز اثاييا قم ثظةييار اثطييراز شييجل رشير اثطيرب ا ااي اثطيرب اثايا و اميت ايراء اثمماثييم ا ا مت اثارجم ف رمار اثقرت اثثيامت رشير ااثتاايف اثمعتمر مف ما تو ف اث طا اثتط ةقةم اياث ةتاضم تيراةم رميار اثقيراةت اثثيامت ااثتاايف رشير ثيرار اثتيارةث اثمعتمر اثثا ة ااثمترةر ف تااةال اثاا ف اي تيف ثيةاةم ف اثعمار الحالة التطبيقية الثالثة ت م اثااثييم اثتط ةقةييم اثمماثيييم فيي اث طييا اثاييا قم ثظةييار اثطييرز اثاييا قم ثظةييار اثارجييم شييجل ةتاضييم مييت تييراة ا ا مت اثطراز في اثعميار اثارةثيم ا ااي اثطيرب اثايا و اميت ايراء اثمماثييم اثمعتمير ميف ميا تيو في اث طيا اثلعيل ايااياا ااثميار في تاايةال اثتط ةقةم اياث ةتاضم تراةم اثعمار اثارةثم ثرار اثتجااثااةا اثمعتمير في اثاا ف اي تيف ثيةاةم ف اثعمار . الحالة التطبيقية الرابعة ث ةتاضييم مييت تييراةم اثااثييم اثتط ةقةييم اثمماثيييم فيي اث طييا اثاييا قم ثظةييار اثطييرز اثاييا قم ثتعييارل ظةييار جييل مييت اثمماثيم اثمعتمر مف ما تو ف اث طيا اثطراز ااثارجم ف رمار ما عر اثارةثم ا اا اثطرب اثاا و امت اراء اثتط ةقةييم اياثيي ةتاضييم تعييارل اثارجييم ااثطييراز فيي رمييار ما عيير اثارةثييم ثييرار جييل مييت اثتييارةث اثمعتميير اثثا يية ااثمترةر ااثتجااثااةا اثمعتمر ف اثلعل اياااا ااثمار ف تااةال اثاا ف اي تيف ثيةاةم ف اثعمار . التطبيقية الرابعه: )التطبيق على العينه المنتخبه(.. الخطوة 2.3.2 اييةتو اثتط ةييو ظاييا مييت يييل ةيياال تاقييو ناثمترةييراة اياااييةه ثي اييس ااثتيي تييو مماثيتةييا مييف اثاميياذج اثمعرفةييه اثمت اياه فيي اث طيياه اثتط ةقةييه اياثيي ر فيي اثعةاييه اثمات ييه ثيتط ةييو اظيي مشييرا مجت ييه اييات فراااةاييجا اثعامييه 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 ثييو ةيياال تاقييو ناثاميياذج اثمعرفةييه اثتيي تييو تط ةقةييا رييي ايطييار اثاظيير فيي اث طيياه اثتط ةقةييه اثثااةييهر فيي امييت اثعةاييه اثمات ييه ثيتط ةييو اا ةييرا اييةتو ةيياال تاقييو ناثمترةييراة اياااييةه ثي اييس اثتيي تييو تط ةقةييا رييي ايطييار ط ةيو ا يل جيل ذثيم ايةتو طيرب اثمعرفيه اثاظرةيه ريت اثاظر ف اث طاه اثتط ةقةه اثثاثثيهر في اثعةايه اثمات يه ثيت -اثعةاه اثمات ه ثيتط ةو ثتاضةاةا تمةةرا ياراء اثتط ةو اجايت : سىىان –مشىىروم مكتبىىه سىىان فرانسيسىىكو العامىىه -العينىىه المنتخبىىه للتطبيىىق: .2.3.2.2 pei. المصىىمم: مكتىىب 2991-2992فرانسيسىىكو ك كاليفونيىىا ك امريكىىىا cobb freed ك المعماري james ingo freed . ماشييا معا يير رييي اثييرغو مييت اياتييراو اث ييارا ثاااةييه اثم ايي اث اراةييه freedتعيير ااةييه اثمجت ييه اثعامييه ل ثماااراته اثمعمارةه ذاة اثتاةج اثتارة اااء ظذا اياتراو اثتارة افيو امير رايم ثياييطاة اثمايةيه ثيمرةايه ياثقر ميت ماييال اثمرةايه grove & fultonما يف ةتاايط شيارر ات يي مايااه اثمجت يه ظجتيار تقرة يا ميت فجييات اثتايياا مييف اثااييةج اثتييارة اااييت راو اثملييرراة اثجياييةجةه ثةتااايي 1115ااثييذ ةعييار تارة ييه ثيعيياو ااث ااةاة اثماااره مت اثمطاثي ايااايةه يااياز اثمشيرا . ةا يذ شيجل اثمشيرا اثمايتطةل في م ططيه اتجاةايه ااييار جتيييه فيي اايير ايرجييات تييرار زااةييه معةاييه اةاييت رو اثم ييمو اثملييرراة اثجياييةجةه مثييل اثعمييره اتجييرار مييف اثلتااة اراا ر ز رفةه معةاه ات اثتقاةو ااء ماره اثجرااةة اي ةض ااثااب جااجرةتةه اثت ر ت را متاا ضه فيي ارمييره اثاااةييه اثرر ةييه اا اثتقاييةو اثشيي ج اثمعتميير اارييا مييا مييف اثميياار اثمعا ييره اثمتمثيييه يياثلايذ ااثماييتعميه ري مارةل ثيثه ا راو. جميا ةاميل اثت يمةو اثيرا ي ثيم يمو تاا ضيا ميف راب اث يارج ميت ييل ارطياء رااةيه ثيمعا ره ااثتي تتاافيو ميف اظةليه اثمااايه نجمجت يه ارةثيه اتجايااةيهر ميف تاظةيف را ير ايترةياو اثملتياب في ه اجييذثم تيياثةر اثلضيياء اثمتاييرم رييت اثشييجل اثماييتطةل رييي ااييو اثلضيياء اثييرا ي املةيياو اثلضيياء ااييط اثمجت يي ر.7-1ر.شجل ر و نjodido,1996,p.112-114اثرا ي اثجياةج .ن الحاله التطبيقيه االولى أ مايرره فيات ظيذه ةتاضم ظاا ااه اثاا ه ثاع اثتجايااةا ااثتيارةث ثتاايةال اا يف ا تيفي ثيةاةيه ارتميار راا ير اثااثه اشر ااارظا ضمت اثعةاه اثمات ه ثيتط ةو مت يل ااتراو اااةه اثم ا ثماااراتةيا اثمعمارةيه ااايت راو ماار ارةثه جاثلايذ اايثااب اثجااجرةتةه اغةرظا. الحاله التطبيقيه الثانيه ب ةجةه ثع ر اثاةضه ارماره اثقرت اثثامت ةتاضم ظاا اثاا ه ثمةل تراةم ظةار اثطراز ف جل مت اثعماره اثجيا ااثتااف رشر امةل ظةار اثارجه ف رماره اثاراثيه اتعيارل ظةيار اثطيراز ااثارجيه في رمياره ميا عير اثاراثيه ةاشر ظاا اتااه مةل ثظةيار جيل ميت اثطيراز اثممثيل ثمايار اطرةقيه اايتعمال ايشيةاء في اثتياثةر اثعياو في اثعةايه يييل اثاضييف اثعيياو ياتييراو اااةييه اثم ايي اث اراةييه ثماااراتةييا اثمعمارةييه ضييمت اثااييةج اثمات ييه ثيتط ةييو مييت اثتيييارة ااايييت راو مليييرراة اثجيايييةجةه مثيييل ايرميييره اتجيييرار اثلتاييياة اراا ييير ز رفةيييه معةايييه. امةيييل ثظةيييار تقاييةو اثشيي ج اثمعتمييير اثارجييه اثممثيييه ثلعييل اثترةييير فيي اثتيياثةر اثعييياو فيي اثعةاييه اثمات يييه ثيتط ةييو مييت ييييل اث اثمارةل اثثيث اي راو ااثرااةه اثمعا ره ثيت مةو اثرا ي اثمتاا ض مف اث ارج. الحاله التطبيقيه الثالثه ت ةتاضم ظاا اثاا ه يرتمار رار اثتارةث اثثا ة ااثمترةر ثتااةال اا ف ا تيف ثيةاةه ف اثعماره ثجل مت اثعماره ماره اثقرت اثثامت ااثتااف رشير اارتميار رار اثتجايااةيا ثيلعيل ايااياا ااثمياره في اثجياةجةه ثع ر اثاةضه ار 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 تااييةال اا ييف ا تيفيي ثيةاةييه فيي رميياره اثاراثييه اارتمييار رار جيةةمييا فيي رميياره مييا عيير اثاراثييه ضييمت اثعةاييه اضييعف ثيتجايااةييا فيي اثمت ييه ثيتط ةييو ةاشيير ااييار رار ييا ثيتييارةث فيي اثشييجل ااثمعاثايياة اث اراةييه مييف رار اثميياار اثماييتعميه فيي اااةيياة اي اةييه. اةاشيير ااييار رار ييا ثيتجايااةييا فيي اثت ييمةو اثييرا ي مييف رار اضييعف ثييتارةث ف ملةاو اثلضاء اثرا ي اثجياةج ثعا ر ايترةاو اثملتاب ف ااط اثمجت ه. طرح وتحليل ومناقشة النتائج: .2.2 اماا شيييم اثاتيييايج اااييي طيييااة اثتط ةيييو اثمتعيييرر عييير ات تيييو اايييراء ذثيييم اثتط ةيييو ايييا قاح ايييةتو طيييرب اتايةيييل اجايت : . تحليل نتائج الخطوة التطبيقية االولى.2.2.2 اشرة اثاتايج ف اث طااة اثتط ةقةيم اياثي اايار تماثيل يةت اثير ارةاامةجةيم جيل ميت اثتجااثااةيا اثمعتمير ثيلعيل اثارجم اثممثيم ثلعل اثترةر اااار تماثل يةت اثير ارةاامةجةيم جيل ميت اثتيارةث اثمعتمير ثيثا ية اياااا ااثمار مف وهىىذا يتوافىىق مىىع التصىىور االفتراضىىي العىىام االول والىىذي ااثمترةيير مييف اثطييراز اثممثييل ثطرةقييم ااييتعمال ايشييةاء يخ( مىىع ان طرفىىي طرفىىي ثنائيىىة اخىىتب بتماثىىل اثىىر طرفىىي ثنائيىىة متغيىىر البحىىث االساسىىيان )التكنولوجيىىا والتىىار النموذج المعرفي )الحركة والطراز(. تحليل نتائج الخطوة التطبيقية الثانية. .2.2.2 الحالة التطبيقية االولى )العمارة الكالسيكية لعصر النهضة( أ اشييرة اثاتييايج ااييار مةييل ثتييراةم ظةييار اثطييراز شييجل ا ييا مييت ظةييار اثارجييم فيي اثعمييار اثجياييةجةم ثع يير وهذا مىايتوافق مىع التصىور اثاةضم ا ط ةعم اثتعامل مف اثقاااةت اثثا تم مااجا اثث اة ف اااةت اثط ةعم )كنموذج معرفىي( فىي العمىارة الكالسىيكية لعصىر االفتراضي الثانوي االول والذي اختب بتحقيق ظهور الطراز النهضة. الحالة التطبيقية الثانية)عمارة القرن الثامن عشر والتاسع عشر( ب اشيرة اثاتيايج اايار مةيل ثتيراةم ظةيار اثطيراز شيجل ا يا ميت ظةيار اثارجيم في رميار اثقيرت اثثيامت ااثتااييف ثط ةعييم اثيي مليياظةو اث ييةرار اثاايي ةم ثتطييار اثتييارةث رشيير اذثييم ايي تطييار اثاظيير مييت اثتعامييل مييف يياااةت ا وهىىذا مىىا يتوافىىق مىىع التصىىور االفتراضىىي الثىىانوي الثىىاني والىىذي اخىىتب بتحقيىىق ارتمييار اثاييةا اة اياتماريياة ظهور الطراز )كنموذج معرفي( في عمارة القرن الثامن والتاسع عشر. الحالة التطبيقية الثالثة )عمارة الحداثة( ت اثاتايج ااار مةل ثتراةم ظةار اثارجم شجل ا ا مت ظةار اثطراز ف اثعمار اذثم ا اثتاجةر ري اشرة تقاثةر ا م ف اثمااجا ااثمعاثام ثيماض طرب تعرةف ا اثطراز ااه اطار ثياما رل ميت اثمثيال اثثا ية بتحقق ظهور الطراز فىي النمىوذج معرفىي وهذا ما يتناقض مع التصور االفتراضي الثانوي الثالث والذي اختب في عمارة الحداثة. الحالة التطبيقية الرابعة )عمارة مابعد الحداثة( ث اشرة اثاتايج ااار مةل ثمعارثم تراةم ظةار جل ميت اثطيراز ااثارجيم في اثعميار اذثيم اي ارتمارظيا اث ايس فييي اثمعاثايييم اثشيييجيةم شيييجل ايييافر اميييتةجو اا ريييت اثمعاييي ميييت ييييل اثمماثييييم اثيراةيييم اثتاجةييير ريييي اثتارة ةيييم وهىذا مىا يتوافىق جزئيىا مىع التصىور ممارام اياةايةم اثم اشر ياتعمال ايشيجال اثتارة ةيم يار اجثير ارفةيم االفتراضي الثانوي الرابع والذي اختب بتحقق ظهور الطراز )كنموذج معرفي( في عمارة بعد الحداثة. 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 34 نتائج الخطوة التطبيقية الثالثة.تحليل .2.2.3 الحالة التطبيقية االولى أ اشييرة اثاتييايج ااييار مةييل ثتييراةم اثعمييار اثجياييةجةم ثع يير اثاةضييم ثييرار اثتييارةث اثمعتميير اثثا يية ااثمترةيير فيي وهىذا مىا يتوافىق مىع التصىور االفتراضىي العىام الثىاني والىذي اخىتب تااةال اثاا ف اي تيف ثيةاةم في اثعميار .بتحقق وجود دور للتاريخ في تأسيس الواقع االختالفي للهوية في العمارة الكالسيكية لعصر النهضة الحالة التطبيقية الثانية ب اثثا ة ااثمترةر ف تاايةال أشرة اثاتايج ااار مةل ثتراةم رمار اثقرت اثثامت ااثتااف رشرثرار اثتارةث اثمعتمر وهىذا مىا يتوافىق مىع التصىور االفتراضىي للعىام الثالىث والىذي اخىتب بتحقىق اثاا ف اي تيف ثيةاةم ف اثعميار وجود دور للتاريخ في تأسيس الواقع االختالفي للهوية في عمارة القرن الثامن والتاسع عشر. الحالة التطبيقية الثالثة ت اشرة اثاتايج ااار مةل ثتراةم رمار اثاراثم ثرار اثتجايااةيا اثمعتمير ثيلعيل ايااياا ااثميار في تاايةال اثاا يف وهذا ما يتنىاقض مىع التصىور االفتراضىي للعىام الرابىع والىذي اخىتب بتحقىق وجىود اي تيف ثيةاةم ف اثعمار ة الحداثة.دور للتاريخ في تأسيس الواقع االختالفي للهوية في عمار الحالة التطبيقية الرابعة ث اشيييرة اثاتيييايج اايييار مةيييل ثتعيييارل تيييراةم رميييار ما عييير اثاراثيييم ثيييرار جيييل ميييت اثتيييارةث اثمعتمييير اثثا ييية ااثمترةييير وهذا مىا يتوافىق جزئيىا ااثتجااثااةا اثمعتمر اثلعل اياااا ااثمار ف تااةال اثاا ف اي تيف ثيةاةم ف اثعميار فتراضىي العىام الخىامس والىذي اخىتب بتحقىق وجىود دور للتىاريخ فىي تأسىيس الواقىع االختالفىي مع التصور اال للهوية في عمارة مابعد الحداثة. تحليل نتائج الخطوة التطبيقية الرابعه. .2.2.2 الحالة التطبيقية االولى أ ه في اثعمياره ضيمت اثعةايه اشرة اثاتايج ااار تاثةراة جل مت اثتجايااةا ااثتارةث اثماااه ثياا ف اي تيف ثيةاة اثمات ه ثيتط ةو. الحالة التطبيقية الثانيه ب اشرة اثاتيايج مةيل ثظةيار جيل ميت اثطيراز ااثارجيه ضيمت اثعةايه اثمات يه ثيتط ةيو ا شيجل اج ير اااضيم اثااي ه ثيطراز. الحالة التطبيقية الثالثه ت ااثمعاثايياة اث اراةييه ارار ييا ثيتجايااةييا اشييرة اثاتييايج رار ييا ثيتييارةث ارار اضييعف ثيتجايااةييا فيي اثشييجل وهىذا مىا يتوافىق مىع ااضعف ثيتارةث ف اثت مةو اثرا ي ااثمعاثااة اثرا يةه ضمت اثعةاه اثمات يه ثيتط ةيو التصور االفتراضي العام السادس والذي اختب بتحقق وجىود للتىاريخ والتكنلوجيىا الميسسىين للواقىع االختالفىي المعماري المعاصر.للهويه في النتاج 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 االستنتاجات. .2.2 اث شيرةم رراايم اثمتاا ضياة ث يةاغم اثاا يف اث يا ةقاو اثماار اثتارة اثاضار اثممثل ثتطار اثط ةعم تلاريييل ايراار اثتارة ةيييم افقييياح ثماطيييو ييياطا جيييامت اضيييمت اطيييار ايايييتمرارةم ييياثتاازت ااثتيييرا ط ميييف رار اثتجايااةييا اثتيي تايياال اةاييار اثايييال ثيمشييجية ضييمت اياتظيياو اثعيياو اثماييار اثاةييا مييف اثط ةعييم ايااييااةم ل تمثةل ري م ايااات ااثعاثو. شجل ماتمر مت ي ةاشير اثييرا ط اثعيياو مييف اثةاةييم اتشييجيةا فيي اثعمييار ميت يييل ريير ظييااظر ااثعمييل ج ييةرم ماضييارةم ثيلجيير تتشا ه ف جل زمات امجات ا لم اثجةلةم ثةا ثةاشر ذثيم اثتيارةث جاتاياه رميار يارر ضيمت ا يةم ( يوضح الخطوات التطبيقية6-1شكل) السعي لتأسيس واقع اختالفي للهوية التأثير في الحالة الثقافية المطروحة الحركة الطراز التكنولوجيا التاريخ التكنولوجيا تماثل في التأثير العام الحركة فعل التغيير فعل انساني مادة الثابت التاريخ والمتغير تماثل في الطراز التأثير العام طريقة استعمال االشياء التكنولوجيا توازي الحركة توازي تماثل التاريخ الطراز تماثل 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 اثذظا ااثمار ثيااات ضمت اثع ر اثراظت ثةجات متيااز ااتمارةم فةما ةتررج رار اثتجايااةا ف اثاتاج مف تطار اثقرراة اثذظاةم ااثمارةم امعةم اي عار اثلجرةم ااي ي ةم ثياضار رماما. ةتااال اا ف اثةاةم اي تيف ر ر اثيزمت ميت ييل تياطةر اا يف جيل ميت اثتيارةث اثمعيرف ثياتيايج في رميةيم قةقةييم اثاايي ةم تارةيير تشييجةل اثتييارةث ثةاةييم ماتمييف طييرب اثثا يية ااثمترةيير ياتيياج امييتيم اثقييةو اثاضييارةم اثا ا ةم معا ر ذاة رااخ زماا امجاا اتامل لم اثلررةم ااثترةر ااثتجايااةا اثذ اثمعرفيه ثيطيار اة اثتيييارة ثلةيييو جيييل ميييا ةاةطةيييا ارتميييار اثعي يييم يييةت اثلعيييل ايااييياا ااثميييار تايييال ايييار فييي اثايييم اثاضارةم ثيااات. ةعتميير اثاااييي اثتط ةقييي ثتاضيييةم اثااااييي اثمرت طيييم تعرةيييف اثاا يييف اي تيفييي ثيةاةيييم فييي اثعميييار ارتميييار ري يييم اثتجااثااةيييا ااثتيييارةث ارتميييار ماشيييراة اظرةيييم مقترايييم اييياا ةت ممييياثيةت ثيمترةيييراة ايااايييةم ة يييالات اثااثم اثثقافةم اثمطراام جمااظر ثاا ف اثةاةم اي تيف .جاماذج معرفةم تاقط ري اا ف اظر راو ةتمثل ترام ااثم ا رمار اطراةيا اثاظير اثمايتقل رار ا مترةير ميت اثمترةيراة ايااايةم اثتيارةث ااثتجااثااةيا تااييةال اا ييف اثةاةييم اي تيفيي فيي اثعمييار افقيياح ثيتماثييل مييف تراةايياة اثطراايياة اث ا ييه ظةييار أ مييت معرفةم ثجل مت اثطراز ااثارجه ةترا ط اةتماثل اثر ارةاامةجةم اثتجااثااةيا اثمعتمير اثلعيل ايااياا اثاماذج اث ااثميار مييف اثارجييم اثممثيييم ثلعييل اثترةيير ااثتييارةث اثمعتمير اثثا يية ااثمترةيير مييف اثطييراز اثممثييل ثماييار اطرةقييم ااتعمال ايشةاء ف اثتاثةر اثعاو اجايت :  ر اثجياةجةم ثع ر اثاةضم ارمار اثقرت اثثامت ااثتااف رشر ظةار اثطراز ترام جيح مت اثعما شجل ا ا مت اثارجم ا اثتاث ترام رار اثتارةث اثمعتمر اثثا ة ااثمترةر.  ترام رمار اثاراثم ظةار اثارجم شجل ا ا مت اثطيراز شيجل ةيرام رار اثتجااثااةيا اثمعتمير ثيلعل اياااا ااثمار .  رمار ما عير اثاراثيم تعيارل ظةيار جييح ميت اثطيراز ااثارجيم معياح شيجل ةيرام رار اثتيارةث ترام اثمعتمر اثثا ة ااثمترةر ااثتجااثااةا اثمعتمر ثيلعل اياااا ااثمار .  تيييراةم رار اتييياثةر ثيتيييارةث ااثتجايااةيييا اثمااايييات ثياا يييف اي تيفييي ثيةاةيييه فييي اثعمييياره ا شيييجل اثقييياه فييي اثاتييياج اثمعميييار اثمعا ييير ميييف مةيييل ثظةيييار جيييل ميييت اثطيييراز ااثارجيييه مت يييارل اثتييياثةر ا ا شجل اج ر اااضم ثيطراز. . التوصيات.2.1  ةا اث اس ضرار اثتاجةر ري اظمةم فةو ارراام رار اثتيق ف تعرةف اثعي م اماياراتةا يةت جيل ميت اثتارةث ااثتجااثااةا ف اثعمار  اثقةاو رراااة ارمو ثعي م جيل ميت اثتيارةث ااثتجااثااةيا في اثعميار في ضياء رراايم ةا اث اس اظمةم اثمااظج اثمعمارةم اثمتعرر ا ا اح فةما ة مااثم اثشجل ااثمعا .  ةا يي اث اييس اظمةييم تاضييةم افةييو ري ييم اثتييارةث ااثتجااثااةييا فيي ضيياء اثمليياظةو اثعامييم ثألطييار اثاظيير اياتمار اثعاو. صادر العربية:الم .2.7 . 1112 تاقةو و .جاترمةرا مجت م ث اات ث اات 1ا ت يرات ر ر اثرامت "اثمقرمم" و .1 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 اازةاال اات مار "اثليالم ااثتقاةاة" ترامم غاث ظياا اثمااام اثاامعةم ثيرراااة .2 .1194ااثاشر ةراة اثمااام اثعر ةم ااثاار ااثتاا " اثاماثةم -"اثعمار اثعر ةم ايايمةم اث ةاا . ر. رل ف .3 .1192ثياتاج اير ااثلا ارماغ اعار ااا ازغيش امز "اثامطةم ةت تارةث اثعمار اماةاةم اي را " اس .4 جااات اثثاا 263ف مايم اثماتق ل اثعر مرجز رراااة اثاار اثعر ةم ةراة ررر 2001 . ؛ ترامم اعار ر ر ري مةر ؛ رار اثشاات اثثقافةم ”اثعمار اتلاةرظا ااتا اات ا اا؛ " .5 . 1116اثعامم ررار ؛ ترامم ر او اثشةث ااو رار اثامةارةم ثياشر ”اضار اثمااه اثثاثثمتافير اثلت؛ " .6 . 1110ااثتازةف ثة ةا رار 3ر اماذاا" طتةزةا طة "اال مشجية اثثار ااثثقافم ف اثعاثو اثثاثس:اثاطت اثع .7 1179رمشو ثيط ارم ااثاشر اارةا اثمااارم اث رةر " اثاظرةم اثتجااثااةم ااثتارةث اثتجااثاا "امةل رراات ر راثجرةو .9 1110 رار اثشاات اثثقافةم اثعامم ررار 344 ايايمةم " اث عر اثاضر ف اثعمار ايايمةم" اثعمار اثعر ةم يا مامر ماار .1 اثماتمر اثمعمار ايال ثاقا م اثمةاراةت ايرراةةت اثمرجز اثمعا ر ن اشجاثةم اثةاةمر" .1119اثثقاف اثميج "؛ اطراام ماااتةر او اثةارام اثمعمارةم رراام اثعمار جيرماث ةاط مامار اامر؛ " .10 .1115اثاامعم اثتجااثااةم ررار اثماتمر اثمعمار تع ةر رت ظاةم اثعمار ايايمةم اثمعا ر "" اثرزا غار ماا .11 1119ايال ثاقا م اثمةاراةت ايرراةةت اثمرجز اثثقاف اثميج اثمايال اثاطا ثيثقافم ا 3" اثط عم "ايايم راثو اثمعرفمزجرةا ر.فاار " اثتلجةر اثعيم .12 1199اثلاات ا ايرا اثجاةة 1111ر ر اثرزاو "ف اثتلاةر ايايم ثيتارةث" اثازاير رار اثشةا اثامراي اعمات .13 ؛ رااثم ماااتةر مقرمم اث ” ةت اثاظرةم ااثتط ةو -اي اثم ااثمعا ر اثاةر اثةر اامر؛ " .14 . 1115جيةم اثرراااة اثعيةا اثاامعم ايرراةم اطراام ماااتةر او اثةارام "؛ اثمراف ف اثعمار اظر ماتق يةمر ار رر ر اال؛ " .15 .2002اثمعمارةم اثاامعم اثتجااثااةم ررار اثعطةم ر.ماا اعلر "اثتعرةت ف اثتارةث اثاضار ثيااات " مايم اثعياو ررر .16 2000 رار اثشاات اثثقافةم اثعامم ررار 112 را ةم ثيةارام اثمعمارةم اثمايم اثع "اثتجااثااةا ا اثاظاو اثتاا ي "اثعي يةل اايماو .17 اثاام اياث اثعرر ايال اثاامعم اثتجااثااةم. " اثماجت ذا اثلااء اثرا ي فرج ر. ااامم مامر ري ااثعطار ر. مامر ر مة اامر .19 2000اثماتمر اثمعمار ايررا اثثاا اةيال اري م ايااات اثعر ايرض ااثاماء " 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 اات ااثتار اثتجااثاا " ترامم اام جعج رار اثطيةعم ثيط ارم فاثجاف ج " ايا .11 1171ااثاشر ةراة -1196 رار اثشراو ث اات 12 ط1 ط اةر "ف ظيل اثقرآت" ج .20 " رار اثشاات اثثقافةم ايمجات ف اثمار ااظر ار رايار ااال اال " .ر اثقةا .30 3110ا -تماز 2-7اثعامم مايم افاو رر ةم ررر " ترامم مامر ر ر اثا ار ا ار / اثتجااثااةا ااثثقافمجراا رج ميلةت اراما ارة اثةاو " .33 .0372مقااية امقتطلاة م تار مااام اال اثعر اثقاظر ؛ ايايم راثو اثمعرفم اثمايال اثاطا ”اثعر اماو تارةاة اثتجااثااةاجرو ااطااةاال؛ " .23 .1192را اثجاةة ثيثقافم ااثلاات ااي ارا اث ا ةم " اثتراس اثمعمار ا ا ةم اثمرةام اثعر ةم اثمعا ر "جماام ر.اةرر .24 1191اثاطاةم ف اثعمار اثعر ةم اثمعا ر اقا م اثمةاراةت اثعرا ةت ررار تجااثااةا اثماثج ر. ةيم فارال " اثعمار اثمعا ر ف اثعاثو ايايم :ظاةتةا ااثر .32 .0332اثع ر فةةا" اثماتمر اثمعمار ايال ثاقا م اثمةاراةت ايرراةةت 3 ترامم فيب راةو اثثقافم اياا ةم ررر"اياتةعا اياماث ثيثم "مملارر ثاةال .26 1194. "؛ رااثم ماااتةر مقرمم اث اثر اقل اثتجااثااةا ف اثعمار اثمايةماثماشر مةااء زةار ؛ " .37 . 1112 او اثةارام اثمعمارةم اامعم ررار اعةو مشار ر راهلل "تااية اثةاةم اثعمرااةم: ثاايةم اثثقافم ااثتارةث ف اثعمار اث يةاةم اث .32 .3111 ث اات 322اثمعا ر " مايم اثماتق ل اثعر مرجز رراااة اثاار اثعر ةم ررر مايم " اثلضال ااثشم ااثتراس..اال فاير اثتارةث اضرره ري اثاةا "تاماال اة اررا .21 .1197 45فجر افت ررر 2.8. المصادر االجنبية: 1. bealline , jean-claude ,1971,” technology from an encyclopedia point of view " in the philosophy of technology , usa 2. conrads , ulrich,1970,” programs & manifestoes on 20th. century architecture land humpies” 3. heidegger, martin, 1977,” question concerning technology in basic writing”, by david farrell krell, harper & raw publisher, new york. 4. jodido,philip, " contemporary amercain architectes: volume iii " taschen ,1996. 5. lynch,kevin, “a theory of good city from” ,cambridge, the mit pross,1981. 6. nesbitt, kate; ”theorizing a new agenda for architecture; an anthology of architectural theory 1965 – 1995 ” ,princeton architectural press, new york, 1996. 7. rogers, richard,”cities for small planet ” faber, londen, press, 1997 8. salya ,yoswadi, "notes on architecture identity in cultureal context" , mimar 1999. 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 المكتبه االفتراضيه: 1. architecture knowledge management: concepts, technologies, challenges authors: gorton, i. --babar, a. journal: 2007 working ieee/ifip conference on software architecture (wicsa'07) year: 2007 pages: 31-31 provider: ieee publisher: ieee doi: 10.1109/wicsa.2007.15 2. an interview with anthony d. king on "spaces of global cultures: architecture, urbanism, identity" author: ali cengi̇zkan journal: middle east technical university journal of the faculty of architecture issn: 02585316 year: 2005 volume: 22 issue: 2 pages: v-xii provider: middle east technical university / faculty of architecture-publisher: middle east technical university / faculty of architecture نترنت: اال المعجىىم اللغىىوي :سلسىىلة معىىاجم لسىىان العىىرب ،الصىىحاح فىىي اللغىىة والمعجىىم الوسىىيط علىىى الموقىىع .1 http://www.baheth.enfo) االلكتروني الخاص بالباحث العربي 2. http://www .oxford dictionaries.com/definition علىى الموقىع االلكترونىي قاموس اوكسفورد 3. http://www.answers.com./topic/history-phyliosophy 32العلفي د. محمد،" الهوية الثقافية الوطنيىة وأثرهىا فىي خصىائص الهويىة المعماريىة "، صىحيفة .4 سىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىبتمبر علىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىى الموقىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىع االلكترونىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىىي : www.26sep.net/newsweekarticle.php?lng=arabic&sid 5. http://www.alriyadh.com/2005/03/26/article50891.html القاموس الفلسفي الوالند .6 http://libhub.sempertool.dk.tiger.sempertool.dk/gmt/ivsl/ieee/_2007___31-31/4077010/4077011/4077048/5/10.1109/wicsa.2007.15 http://libhub.sempertool.dk.tiger.sempertool.dk/gmt/ivsl/ieee/_2007___31-31/4077010/4077011/4077048/5/10.1109/wicsa.2007.15 http://libhub.sempertool.dk.tiger.sempertool.dk/libhub?func=search&query=au:%22gorton,%20i.%22&language=en http://libhub.sempertool.dk.tiger.sempertool.dk/libhub?func=search&query=au:%22babar,%20a.%22&language=en http://libhub.sempertool.dk.tiger.sempertool.dk/gmt/ivsl/doaj/02585316_2005_22_2_v-xii/jfa.arch.metu.edu.tr/archive/0258-5316/2005/cilt22/sayi_2/interview.pdf http://libhub.sempertool.dk.tiger.sempertool.dk/gmt/ivsl/doaj/02585316_2005_22_2_v-xii/jfa.arch.metu.edu.tr/archive/0258-5316/2005/cilt22/sayi_2/interview.pdf http://libhub.sempertool.dk.tiger.sempertool.dk/libhub?func=search&query=au:%22ali%20ceng%c4%b0zkan%22&language=en http://www.baheth.enfo/ http://www.baheth.enfo/ http://www.answers.com./topic/history-phyliosophy http://www.26sep.net/newsweekarticle.php?lng=arabic&sid http://www.26sep.net/newsweekarticle.php?lng=arabic&sid http://www.alriyadh.com/2005/03/26/article50891.html 3102لسنة -العدد الثالث المجلد السادس مجلة القادسيه للعلوم الهندسيه 33 -1992سان فرانسيسكو ، كاليفونيا ، امريكا –مشروع مكتبه سان فرانسيسكو العامه ( 7-1شكل رقم ) . james ingo freed، المعماري pei cobb freed. المصمم: مكتب 1996 article al-qadisiyah journal for engineering sciences 12 (2019) 049–055 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7815277599. e-mail address: hamed73.a@yahoo.com (hamid a almousawi) https://doi.org/10.30772/qjes.v12i1.591 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. a biotic balance of objects with nature as an architectural destination: (marsh houses as case study) hamid ali abed almousawi a*, mustafa kamil kadhima a department of architecture, university of technology , baghdad, iraq a r t i c l e i n f o article history: received 27 march 2019 received in revised form 19 april 2019 accepted 30 april 2019 keywords: bio balance harmony marshes a b s t r a c t the biotic balance is a special strategy followed by the building, which helps it to stay and interact, and perform vital functions at a constant and natural rate under suitable conditions or the possibility of making them suitable, in the light of the general trend that seeks to preserve nature, as a result of the emergence of concepts of sustainability and green architecture and applied models of polarization outside the environment which resulted in buildings that are not compatible with the environment and thus reduced environmental performance of the building, emerged the research problem of "lack of knowledge about the mechanisms of living organisms to achieve a biological balance with the surrounding nature." the main objective of the research was to "build a cognitive perception about the mechanisms by which living organisms create a biological balance with the surrounding environment." therefore, the main research hypothesis was that there is a similarity between the mechanisms used by living organisms to balance the surrounding nature and the architectural solutions that the architect must follow to achieve the same harmony with the surrounding nature, "and therefore adopted the methodology of research on two parts: first: the theoretical study, which includes the introduction of concepts and considerations related to the concept of biological balance, and knowledge of the mechanisms used by living organisms and try to apply in the field of architecture, the study concluded that the strategies of living organisms in dealing with the surrounding environment, along with the automatic architecture of marsh homes, is the basis of the main hypothesis and its applicability. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the research deals with two main areas: theoretical study and practical study. the research concludes with a set of conclusions and recommendations that represent the theoretical and practical conclusions of the study. the theoretical study deals with the concept of biological balance and how to measure the mechanism of the organism. the biological balance and mechanisms followed by architecture and try to find elements of similarity between them, to try to build a cognitive perception of those mechanisms and use in the production of architecture in line with the surroundings. the study included the handling of models of marsh houses and the comparison of the construction of the balance of organisms living in the marsh environment, and the use of these mechanisms in the construction of buildings in harmony with any other environment, in http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i1.591 50 hamid a almousawi , mustafa k kadhim /al-qadisiyah journal for engineering sciences 12 (2019) 049–055 addition to the presentation of the results and recommendations. fig. 1 shows the path that will follow the research to achieve the above. figure 1. shows the research path (preparation of the researchers) 2. theoretical study 2.1. basic concepts of research 2.1.1. the linguistic and theological concept of biological balance: when researching the linguistic assets of the terms of the terminology and terminology of the concept of balance, these astolol contribute to the extraction of synonyms and similarities of language and at the same time contradictions of the balance of balance, so the synonyms of balance are two cases:  the system: corresponds to the (compatibility compatibility homogeneity), ie the situation in which things are placed in relationship with each other.  the model: corresponds to the (example type format) [1], but the meaning of the word vital "practical study of the interaction that determines the distribution and number of objects"[2] ie represents the biological balance study of objects in their environment. figure 2. illustrates some of the marsh dwellings in southern iraq (source: https://www.google.com/search?ei 2.2. balance in architecture: "the state in which each part of the composition has a fixed problem and the sphere of the fixed, nothing is added or eliminated without the total homogeneity,"[3] as francis ching defines the balance as "a homogeneous and relative organization of contradictory parts or elements , interactive, opposite) within a particular design or situation. "[4] an equilibrium is the state of harmony between the building and the surrounding environment. abiotic balance: it represents the biological balance of living organisms within their environment, the medium that occurs at the beginning of the relationship or known as the ecosystem[5], which is due to many of the biological processes, which are evidenced by the internal biological medium with the external environment despite the change of climatic factors. bbiotic balance mechanisms: the concept of biological balance of organisms, we conclude that the ability to survive within the ecosystem requires flexibility during the interaction of the organism with the elements of the ecosystem and its environmental determinants. the environmental determinants of the lachroho system differ in the distinctive features of each ecosystem. environmental determinants however, organisms have been able to survive and overcome these environmental determinants and changes by adopting methods that are compatible with their environmental environment and with the diversity of domains as well as the organisms they coexist with. the methods in which organisms achieve balance and harmony which is due to the multiplicity of the acquisition of each group of organisms characteristics or characteristics are different from another group of beings of the same species living in a different environment these attributes are called adaptations, which is characteristic of an object that enables this organism to live under the conditions of its environment is called adaptation, special adaptation organisms enable the biological balance with the environmental environment these adaptations in the organic composition of the external form and an internal structure suited to the functions of the object, which is called organic composition complemented by a set of behavior behaviors called behavioral adaptation, those adaptations that all organisms can be called mechanisms t realize the vital balance. 3. the marshes are the lowlands covered by the water both in all the days of the year or in some of them. there is no clear difference between the marshes and marshes, and the people of southern iraq call the marshes generally on ponds or lowlands that are filled with deep shallow water in southern iraq and sedimentary plain, where the reeds, the golan and the papyrus[6] . the ecosystem of the marshes also includes shallow land that is submerged in water for a period of the year and is formed by the accumulation of rain water above the surface of the earth or as a result of the flow of water over a land surface especially in areas close to groundwater sources and rivers. the sources of marshes are subject to change. permanent or fixed rate may flourish year-old and other year-old moths so living organisms in the marshes characterized by seasonal. https://www.google.com/search?ei hamid a almousawi , mustafa k kadhim /al-qadisiyah journal for engineering sciences 12 (2019) 049–055 51 4. previous studies  the study of mashhadani, yahya dawood, plants and their environment, 1987[7] : for example, light affects a number of vital functions of plants with different values and by plant type and different growth stages of plant age. plants grow in light and others grow. in the shade, between the plants of shade and light called the adaptive ability to live in any amount of lighting with the optical balance of plant. we conclude from the study that the biological balance is meant to adapt to climatic conditions.  the study of awadat, mohamed abdo, and others, plant morphology and slice, 1992[8] : the study indicates that the biological balance is the flexibility and dynamism that gives the plant harmony with the changing environment. this is achieved through changes that affect the two main components of the plant, namely vegetative and root. the balance includes the change in shape and branches at the leg level, and the surface materials of the plant, the smooth surface of the aquatic plants may be rough in the desert plants, due to the control of the number and area of the holes to create a thermal balance with the ocean. we conclude from the study that the biological balance is intended to include the external and internal part and consists of different levels of the parts of the plant.  the study of hamoud, mohamed hassan, and others, human biology, 2002[9 ] : this study may vary in the animal kingdom to determine the thickness and material of the outer shell of the animal. in dry and warm environments, it is characterized by the thinness of the sweating process, in humid environments it is thick to resist extreme cold. we conclude from the study that the biological balance is a process that depends on the interaction and influence interactively between the animal and the external environment.  study "chapman" ecology principles and applications 1992[10] : the study deals with the concept of biological balance as a part of organic life and the group of living relationships that live in the ocean or the environment. the study also shows that the biological balance includes the study of animals and plants and their relation to their environment. it also indicates that the biological balance is the interaction between the living organism and the surrounding environment in mutual relationships through which the organism seeks to continue and develop. this balance is divided into two levels, namely the level of the organism and the surrounding ecosystem, the biological balance is the interaction between the environment and the organism, which ensures the continuity and evolution of the organism.  dickinson gordon & other study, "ecosystems: a functional approach" 1998[ 11 ].the study indicates that the functional biobalance is a special strategy to cope with the changes and disturbances that occur within the ecosystem, which ensures the continuity and balance of objects during their interaction and performance. the study also points to the mechanisms of balance that arise in living organisms, such as avoidance, resistance and circumvention. the bio balance is part of the principle of adaptation to the environment. the study also discusses the biological balance of climate, which includes interaction with the surrounding climate through the amount of rain and vegetation, temperature and relative humidity. the study also describes the biological balance as the ability of the ecosystem of the organism to vary and vary according to the environment (desert, forests, lakes, etc.). we conclude from the study that the intended balance is the functional balance, while the study did not address the other aspects of the balance of form and behavior and others. table 1. shows the focus of previous studies (preparation of the researchers we conclude from the previous studies that the table above shows the aspects of each study that the biological balance in general, and most of the studies were outside the field of architecture, in addition to the biological balance was handled in most studies that leads to survival, not development and survival together, but most of the studies did not address the mechanisms and levels of biological balance and the possibility of using these mechanisms in other areas and within different environments, so it was one of the reasons for the emergence of the research problem. 4.1. :the research problem: having mentioned in the previous paragraphs the most important studies that dealt with the biological balance and its relationship to the survival and persistence of living organisms, we note our lack of a specialized architectural study, since all the previous studies were outside the field of architecture. we also noted that most studies dealt with any vital balance in general, without explaining its mechanisms and levels, and the possibility of using these mechanisms and methods in other areas and in different environments and by other organisms, and here we mean specifically the human and the field of architecture, and therefore the general problem of research can be identified by (b) the lack of knowledge of mechanisms and methods biological balance of organisms). 4.2. : determination of the objectives of the research: after identifying the problem research must identify the main objective of the research is ((understanding and understanding the mechanisms and methods of biological balance of living organisms, and the possibility of using these mechanisms in the formation of an architectural product is consistent with the environment). which is reached through the secondary objective: to arrive at conclusions about the similarity between the mechanisms of the organism and architectural design, specifically through c o n c e n tra tio n m a sh h a d a n i, y a h y a a w w a d a t,m o h a m e d h a m o u d ,m o h a m e d c h a p m a n d ic k in so n g o rd o n & o th e r type of study architecture nonarchitectural p la n t a n im a l interesting study shape function behavior balance climate topography direction balance enterir exterir possible value balance form continues evolve 52 hamid a almousawi , mustafa k kadhim /al-qadisiyah journal for engineering sciences 12 (2019) 049–055 the handling of marsh houses in southern iraq and some structural models that tried to simulate those houses. 4.3. the theoretical framework of the concept of biological balance: in this paragraph will identify and analyze a range of architectural studies close to the framework of the research. to solve the research problem as it provides the basic vocabulary through which the different aspects of the research problem are measured. and to prepare the requirements for practical application through the selection of samples of marsh houses or houses were built according to the mechanisms of construction of marsh houses that will be applied to the measure, and identify the vocabulary and variables of measurement and determine methods of measurement and astrology and the construction of hypotheses main and secondary research, and to extract and analyze the results of practical application of research, then put forward conclusions, and finally put forward the final conclusions. 4.4. previous studies on bio-balance:  dabsen, ysri, "nature reserves and environmental balance ", 1999[12]: the study indicates that the biological balance is part of the ecological balance and a condition for its continuity. it is the process by which organisms seek to achieve their balance through the use of the principles of nature. there are many alternatives in organisms to conform to the biological balance is the behavior of the organism that is created according to the surrounding environmental variables. the reproduction of animals and plants is not done through an engineering sequence. the decrease of food and the feeling of increasing its numbers prevents it from multiplying, migrating or redistributing its spread. the study of biological balance is closer to the flexibility of the organism to survive, a process of interaction depends on the impact of the environment and the extent of the object  arafa study, salah "environmental balance and the establishment of human settlements " 2000[13]: the study indicates the biological balance is the interaction of elements of the environment in groups, each group is an environmental range (a living area) has characteristics distinguish it from other neighboring environmental ranges, environmental elements, such as the prevailing climate, soil components (non-living elements) and the quality of plant and animal life (living elements), where living elements interact through a reciprocal relationship that depends on each other in a part of his life. we conclude from the study that the biological balance is an interactive process with mutual benefits that is similar to coexistence to form a vital society, which interacts with the environment.  the study of bayoumi, hussein, "the machine of nature: ecology from an evolutionary perspective ", 2000[14]: the study indicates the dynamic balance as the dynamics and the interplay between the systems to cope with environmental changes, which helps continuity. the study also describes the biological balance in the integration between organisms and the surrounding environment. the amount of the biological balance the quality of the properties of the overlapping ecological systems and the topographical and physical barriers that separate the systems, which make them very sensitive to environmental changes. we conclude from this study that a dynamic balance is a dynamic integration process that relies on flexibility in dealing with external variables.  nebel "enviroment science" study 2000[15] : the study indicates the biological balance as a periodic exchange process occurs in two directions, once towards the organism and the other direction of the outer perimeter, and this cycle includes the transfer of materials and energy, and although each cycle has different characteristics, in the end we find that each of them complement the other, and the process of exchange through the outer envelope, influenced by factors such as climate, which includes temperatures, humidity and rainfall rates, as the study to balance levels, and put those levels within the hierarchy, in the general structure, where the product represents the base and the material the balance will lead to the loss of the relationship between them, where some consumers resort to reduce their preparation for the existence of imbalance in the burner, which is due to the disturbances that occur in the environment of the surrounding. we conclude from the study that the biological balance is a periodic exchange between the organism and the surrounding environment according to levels affect the nature disorders and external changes.  batton study "physical geography" 1974 [16] : the study indicates that the biological balance is the functional harmony of the organism with the outer environment, the members of the organism acquires a group of features or specifications to suit the changes in the external environment, in contrast to the members of similar functions in the organisms of different environments, where the members adapt to meet the effects of the external environment, so as to achieve consistency between the internal biological medium and the external environmental environment. we conclude from the study that the functional balance of functional is the harmony or suitability or adaptation of the components of the organism components of the environment.  brown study "the relation of evaporation to the water content of the soil the time of wilting" 1998 [17 ] the study deals with the biological equilibrium through the term adaptation, which leads to ecological balance. the biological equilibrium is defined by the range of differences in characteristics and characteristics of the organism, acquired as a result of continuous exposure to different environmental conditions for a long period of life cycle, the study indicates that the biological balance leads to formative changes in organisms of the same species, when they grow in two different environments, such as the aquatic environment and the terrestrial environment, where the total root of the nucleus decreases t that grows in the aquatic environment while expanding the ground environment to balance the absorption alme.nstkhals of the study that the vital balance is adapted to a functional change, followed by a configurable output from the organism affected by the environment surrounding the process. 4.5 . abstract: the main and secondary vocabulary and its possible values, which represent the conceptual frame, were identified. thus, the research achieved its first objective in constructing a theoretical framework on the biological balance of the living organisms and the effects on architecture, and the vocabulary came as follows 5. application in the practical study, the vocabulary of the theoretical framework will be applied to a selected group of samples. for the purpose of the research, the vocabulary of the effect of interaction with the environment on the external appearance and the flexibility of formality to respond to environmental variables will be chosen. 5.1. test the hypothesis of research: this research was based on the hypothesis of the main (the existence of a similarity between the mechanisms and strategies of living organisms to balance with nature and architectural solutions that must follow the architecture to achieve the same degree of harmony within the environment itself). the research was hamid a almousawi , mustafa k kadhim /al-qadisiyah journal for engineering sciences 12 (2019) 049–055 53 based on the analysis of the detailed explanatory texts, drawings and explanatory diagrams of a number of selected projects. the analysis included several stages: 5.2 : a general description of the project based on the sources and reanalysis of each project according to the specific vocabulary for the measurement and the descriptive charts and illustrations. 5.3 : the specialized description and measurement form contains a detailed explanation of each secondary variable within the specific adaptation vocabulary. the two components (the effect of interaction with the environment on the external appearance, the effect of formal elasticity on response to environmental variables) and the effect of formal elasticity on response to environmental variables in the form (1), which shows how the possible values will be based on the nature of the relationship between each of the two selected members of the measurement and secondary indicators as stated in the form, which was later applied to the selected samples, based on information table 2. all the elements of the general theoretical framework. (preparation of the researchers). obtained from examples of projects for each of the elected, and in line with the goal of research. 6. analysis of the results this section includes the discussion and analysis of the results of the application derived from the variables measurement form on selected projects based on the exccel program to calculate the percentage of each variable according to the selected projects. the results related to the individual (the effect of interaction with the environment on the outside) the effect of formal flexibility on responding to environmental variables) to the differences between their indicators and their impact on the biological balance: table 3. shows the description and measurement form to measure the variables by determining values ranging from 0-0 (0: not verified, 1: weak, 2: acceptable, 3: good, 4: very good) for the sum of variables. (preparation of the researcher). k e y v o c a b u la ry s e c o n d a ry v a ria b le s p o ssib le v a lu e s fo r th e th re e sa m p le s f irst p ro je c t (p 1 ) s e c o n d p ro je c t (p 2 ) t h ird p ro je c t (p 3 ) t o ta l t o ta l v a lu e s a s a p e rc e n ta g e t h e e ffe c t o f in te ra c tio n w ith th e e n v iro n m e n t o n th e e x te rn a l fo rm , (a ) o u te r sh e ll ( a 1 ) exploitation of renewable energy sources 2 4 4 01 %8 dimensions, proportions and outer space 4 4 4 02 01% shape, size and area of openings 3 4 2 9 7% form fonts 3 4 2 9 7% colors and texture 4 4 2 01 8% softness and roughness in the walls 4 4 3 00 9% in te rn a l m e d iu m (a 2 ) use hollow walls 4 1 3 7 6% thickness of walls 4 2 4 01 8% f o rm a l e la stic ity o f re sp o n se to e n v iro n m e n ta l v a ria b le s (b ) th e sh a p e ( b 1 ) local materials 4 4 1 8 7% porosity 1 4 2 6 5% ا orientation 3 3 4 01 8% f u n c tio n (b 2 ) external closure and internal openness 4 2 3 9 7% shape and surface area 4 4 4 02 01% p o ssib le v a lu e s s in g u la rity 2 s in g u la rity 1 th e m a in s in g u la rity exploitation of renewable energy sources effect of the environment in the building e x te rn a l e ffe c to f in te ra c tio n w ith th e e n v iro n m e n t o n th e e x te rn a l fo rm dimensions and proportions of outer cover the mutual influence between the building and the environment shape, size and area of openings effect of building in the environment form fonts colors and texture softness and roughness in the walls use hollow walls one activity in te rn a l thickness of walls several activities local materials harmony fo rm a lism t h e e ffe c t o f fo rm a l fle x ib ility o n re sp o n d in g to e n v iro n m e n ta l v a ria b le s. porosity orientation repulsion surface shrinkage and width (mobile interfaces) contrast and distribution of structural elements. increase functional efficiency f u n c tio n a l external closure and internal openness functional inefficiency shape and surface area 54 hamid a almousawi , mustafa k kadhim /al-qadisiyah journal for engineering sciences 12 (2019) 049–055 figure 3. shows the analysis of the results of achieving the biological balance formality through the single (impact of interaction with the environment on the outside) the ratio of the effect of the individual indicators (the effect of interaction with the environment on the external form) varied in effect on the level of achieving the biological equilibrium. the index of the use of (dimensions and proportions and the area of the outer envelope) achieved the highest percentage of 11% (thickness of walls) by 8%, while the indicators of (shape, size and area of openings), (lines shape) were 7% finally, the index (using hollow walls) was 6%,as shown in figure (2). figure 4. shows the analysis of the results of achieving the biological balance formality through a single (the effect of formal flexibility on the response to environmental variables) the effect of the individual indicators (the effect of formal elasticity on the response to environmental variables) varied in effect on the level of achieving the formal biological balance. the use index (shape and surface area) reached 9%, while the steering index came at 8% (external closures and internal opening), (domestic materials by 7%), and finally the porosity figure .5. shows the ratio of the effect of the individual (the effect of interaction with the environment on the external form) to the physical equilibrium was 63%, while the other effect (37%) was as follows 7. similar examples 7.1 the first example 7.2 : the second example hamid a almousawi , mustafa k kadhim /al-qadisiyah journal for engineering sciences 12 (2019) 049–055 55 7.3 : the third example 8 :conclusions:  formal biological balance is an interactive process, through which to develop principles that can be applied to architecture, in the framework of an introduction to the nature of the marshes.  the formal bio-balance contributes to the determination of the distance or space of the organism's environmental environment, which helps architecturally determine the exterior shape of the building and guide it and the relationship of anchors to the surrounding environment.  compatibility of strategies and mechanisms of living organisms in the harmonization of the environment with the mechanisms of architectural design, and is done through the following: a dynamic interaction is the ability to control the amount of interaction with the environment and change the color of the outer surface from separation to separation and move from one location to another in order to shade gives the object a great deal of compatibility, which can be applied to the architecture. the exterior coating of light colors with the possibility of turning to dark colors at a very low temperature at night, which is available in the characteristics of natural plastics. b isolation between the inside and outside marshlands deliberately isolate the biosphere from the inner environment by increasing the thickness of the outer wall and its permeability and containing special materials that have the ability to heat insulation. this is one of the principles of marsh objects to achieve the equilibrium of the biological medium, which can be applied to urbanization, of materials with thermal insulation capability. c) external closure and internal openness reducing the holes and pores open to the environment and inward orientation, which enables the marsh objects to avoid the sharp changes of the physical medium, which can be applied to the architecture, such as reducing the proportion of openings in the outer shell to avoid the impact of environmental variables inward direction through the interior and interior spaces. d avoid the surface of the earth  humans are called to avoid the surface of the earth, which is rapidly affected by the change of the state of the physical medium such as high or very low temperature, so that the marshes escape to the depths of the earth where the observed decline and relative stability to the temperature or resort to the vertical direction away from the impact on the surface of the earth an application to urbanization, such as resorting to the soles of the earth, a trend that is used instinctively in models of automatic construction and represents one of the modern trends or what is known as the infrastructure.  a conceptual design can be presented that draws strategies and guidance from the environment.  proved models of automatic construction (marsh houses), the compatibility of both the mechanisms of objects and architecture in the principles of each.  consider biological balance as a principle of architectural design principles, no less important than other design principles. references [1] munir baalbaki, the resource (english-arabic dictionary) beirut dar elelm for millions, 1984, p. 159. [2] chapman, and other, "ecology principles and applications", cainbridge university press, u.s.a, 1992. [3] aesthetics & psycho-biologyknewyoukk1971. [4] francis,d.k,ching,form ,space and order(firest edition).1984.p28 [5] the interaction of the ecology (study of organisms in their environment) with environmental elements, and ecosystems combine to form the biosphere. [6] khalaf, jasim mohammed, iraq's natural, economic and human geography, institute of higher arab studies, 2, 1961, p. 132. [7] mashhadani, dawood, plants and their environments, directorate of dar al-ketub, university of mosul, iraq, 1987.p35 [8] awwadat, mohammed abdo, others "plant morphology and anatomy" university of king saud, riyadh, saudi arabia, 1992.p (22-23). [9] al-hamoud, muhammad hassan, and others, human biology, national publishing and distribution, amman, jordan, 1997.p29. [10] chapman, and other, "ecology principles and applications", cainbridge university press, u.s.a, 1992.p144 [11] dickinson, gordon &other. "ecosystems: a functional approach", routiedge, new york, u.s.a.1998.p12 [12] dabson, yousra, nature reserves and environmental balances, bitash center, alexandria, egypt, 1999 [13] arafa, salah, environmental balance and the establishment of human settlements, arab regional conference, february, 2000. p3. [14] bayoumi, hussein, "machine for nature: ecology from an evolutionary perspective," supreme council of culture, cairo, egypt, 2000. pp. 27-28. [15] nebel,bernads,enveronmental,science,prontic-hall,usa,2000.p33-34 [16] batton,c.f,”forcetry,horticculture and the moon”for,abstr.1946.p46 [17] brown,w.h, the relation of evaporation to the water comtent of the soilthe time of wilting”plant world,1912.p37. microsoft word 1.doc al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 22 tensile strength of high strength polymer modified concrete qusay a. jabal al-kufa university, engineering college (civil. dept) abstract high strength concrete is widely used especially during the last century. high strength concrete means concrete with max. compressive strength ( cf ′ )more than 50 n/mm2 (shetty, 1988). polymer modified concrete was) used since 1970s by adding polymer monomers such as styrene butadiene rubber (sbr) to ordinary concrete during casting as a percentage of weight of cement in order to improve the mechanical properties of concrete. this research includes the study of the effect of styrene butadiene rubber on tensile strength of polymer modified concrete pmc, also include the effect of the polymer on compressive strength and relationship between tensile and compressive strength (as a mathematical model). a different types of mixes (1: 1.5: 2, 1:1.5:3 and 1:2:4) were used in this research. keywords: polymer modified concrete, compressive strength, tensile strength, styrene butadiene rubber, cylinder splitting مقاومة الشد للخرسانة المطورة بالبوليمر والعالية المقاومة قصي عبد الحميد جبل العطيه جامعة الكوفة قسم الهندسة المدنيه– آلية الهندسة الخالصة ي إن الخرس دأت ف ي ب شائية والت صناعة اإلن ي ال تخدام ف شائعة االس واد ال ن الم بحت م البوليمرات أص ورة ب انة المط .السبعينات من القرن الماضي في اليابان والواليات المتحدة ثم شاعت االستخدام على مستوى العالم البوليمر أيضا استخدمت بصورة شائعة في القرن الماضي والخرسانة الخرسانة العالية المقاومة مثل الخرسانة المطورة ب ميكا باسكال واستخدم هذا النوع من الخرسانة ) 50(العالية المقاومة تعني الخرسانة التي مقاومة انضغاطها العظمى أآثر من أثناء صب في بداية السبعينات عن طريق إضافة مستحلبات البوليمرات مثل مستحلب الستايرين بيوتادين للخرسانة االعتيادية ,.الخرسانة وإنتاجها آنسبة مئوية من وزن االسمنت لتحسين الخواص الميكانيكية للخرسانة االعتيادية البوليمر ويتضمن هذا البحث تأثير هذا المستحلب على مقاومة ويتضمن أيضا تأثير إضافة نسب الشد للخرسانة المطورة ب النضغاط واستخراج موديالت رياضية لهذه العالقات إضافة إلى استنباط على مقاومة ا ) الستايرين بيوتادين ( مختلفة من الرآام : الرآام الناعم : االسمنت ( موديل رياضي يربط مقاومة االنضغاط بمقاومة الشد وتم استخدام نسب خلط مختلفة من .في هذا البحث) الخشن al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 23 nomenclature ft : splitting tensile strength (n/mm2) fc : compressive strength (n/mm2) p : the applied load of machine (n) l : height of cylinder specimens (mm) polymer modified concrete pmc this type of concrete means a concrete composed of cement latex and aggregates with polymer added as a percentages by weight of cement. this type of concrete can be used for high loaded structural members and also for both pre-cast and prestressed concrete (vipulanandan, 1990) tensile strength of " pmc " the study of tensile strength of concrete is very important . for prestudies , the increase of compressive strength leads to increase tensile strength. there is a different relationships between compressive and tensile strength; some researches, gives the tensile strength as a percentage form the compressive strength ranged between 1/8 to 1/12 (neville, 1995). this investigation gives a better improvement in tensile strength, and also a better ( cfft ′/ ) ratio .indirect tension test is used in this study by splitting of cylinder using the following equation (eq.1 ) dl p f t π 2 = …(1) the high value of tensile strength may lead to use less tension bars of reinforcement and make the construction of building more economic. aim and scope of work the aim of this investigation is to study the effect of (sbr) polymer on tensile strength pmc and also the optimum p/c(polymer/cement) that gives the higher values of both compressive and tensile strength also anew mathematical model is suggested to relationship between: p/c with tensile strength, p/c with compressive strength and tensile strength with compressive strength. materials ordinary portland cement (type i) was used in this work. aggregates with specific gravity of 2.79. the max: size aggregate is 10mm with grading shown in this table 1 blow . sbr polymer with specifications shows in table 2 was used in this study. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 24 concrete mixing procedure aggregates were added to a mechanical mixer with max. capacity of 0.1m3 before adding the cement . after adding the cement, the mixer turned on with adding water according to w/c ratio then the (sbr) polymer should be added to be the homogeneous mix and the mixing should be continued until all particles are fully coated with (polymercement paste) matrix. also, the total mix should have a uniform or homogeneous colour. ohama (ohama, 1998) adopted this procedure under title "modification with liquid polymers", also this mixing procedure was illustrated by radomir (radomir, 1998) program layout the program layout is shown in (1). curing using air curing in all polymer mixes, specimens of dimensions (150 × 300mm) were cured in water for six days and 21 days in air with temp ( average temp. 20oc) this is the best method of curing. radomir (radomir, 1998) illustrate the best method for curing for polymer modified concrete see figure (2) specimens using (3) specimens for each mix, the specimens of dimensions of (150×300 mm) where used for both compressive and indirect tension tests, capping were used only for compression tests . the max. size aggregates for all mixes was 10mm. (w/c) ratio used in this study were: 0.30 for polymer mixes and 0.35 for reference mixes because of the action of polymers that's tend to reduce the w/c ratio for concrete and improve the mechanical properties (bentur, 1982) specimens tests a.compressive strength tests using rate of loading according to astm (39/c 39m-2001), (astm, 2001) standard specifications for determination of static modulus of elasticity and poisons ratio of concrete in compression. this test was done using ele compression testing machine with max capacity (2000 kn). capping is done in this work for all cylinder specimens (for compression test ) in order to obtain uniformly distributed load under applied load, and also to obtain accurate readings, the capping was made by means of cement paste and by glass plate of about 7mm in thickness and of a length about (diameter of cylinder +30 mm) (shetty, 1988). the capping was done after (4hrs) of casting so that the concrete in cylinder mould undergoes plastic shrinkage and subsides fully. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 25 b. indirect tensile strength " cylinder splitting " a three specimens for each mix were used and also the same rate of loading and same ele testing machine is used. c. development of tensile and compressive strength, and mathematical models. table 3, shows the effect of the increase in p/c ratio on compressive strength, p/c of 15% gives the higher value of compressive strength (or optimum value ) for all mixes. (1:1.5:2) (cement :fine agg.: coarse agg ) mixes gives the maximum compressive strength of about (83.3) mpa. table (4), shows the effect of the increase in p/c on tensile strength, 15% p/c is the optimum p/c that gives the maximum tensile strength for all mixes; both tensile and compressive strength are improved by adding polymer, this improvement due to double influence of polymer caused by the polymer films formation of sbr polymer and a comatrix phase is formed by both cement hydration and polymer film formation processes (ohama, 1997). also, another factors that causes improvement in the properties for this type of concrete; the first is that the voids in this type of concrete is fill up by polymers, and some polymer particles bond with cement hydrates and silicate surfaces of aggregates. also, some chemical reactions may take place between the particles surfaces of polymers and calcium ions (ca+2), ca(oh)2 solid surfaces, or silicate surfaces of aggregates (sujjavnith, 1998). figure (3), shows the effect of the increase in p/c up to 25% of weight of cement on the compressive strength for different mixes. the mathematical model shown in equations 2,3 and equation 4. fc =-0.1757 *(p/c)2 +5.297 * (p/c) +39.29 …(2) r2 = 0.88 [ for mix. proportion =1:1.5:2] fc =-0.135 *(p/c)2 +4.945 * (p/c) +28.92 …(3) r2 = 0.98 [ for mix. proportion =1:1.5:3] fc =-0.093 *(p/c)2 +3.316 * (p/c) +27.54 …(4) r2 = 0.96 [ for mix. proportion =1:2:4] where : r2 correlation coefficient figure (3), it can be seen that optimum p/c ratio is found as 15% , this optimum p/c was also found 15% for maximum tensile strength. figure (4), shows the effect of p/c on tensile strength of (pmc), the mathematical model also given in equation (5), (6) and equation (7) as follows: al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 26 ft =-0.0277 (p/c)2 +0.989 (p/c) +4.79 …(5) r2 = 0.96 [ for 1:1.5:2 mixes] ft =-0.0126 (p/c)2 +0.62 (p/c) +3.246 …(6) r2 = 0.98 [ for 1:1.5:3 mixes] ft =-0.0133 (p/c)2 +0.607 (p/c) +2.739 …(7) r2 = 0.96 [ for 1:2:4 mixes] a straight line related the data in figure 5 with equation illustrated as equation (8). this equation is a perfect equation shows that the increase in compressive strength due to the increase of (p/c); leads to increase in tensile strength, in this research the increase in tensile strength is more than (1/8) of fc' [as in the previous investigations]. now we can see from table (3), if cf ′ =83.3 gives indirect tensile strength cf ′ =13.9, the ft/fc' ratio equals to 1/6, and also for some other mixes the ratio becomes more than 1/6 , this due to the action of (sbr), while the ratio of ft/fc for ordinary concrete of the same mixes without (p/c) gives (ft/fc') ratio of about (4.4/36.1)=(1/8.2). figure (5) shows a relationship between tensile and compressive strength of (pmc). fc= 4.538(ft)+18.004 ….(8) conclusions 1concrete specimens with different mix proportions developed with adding polymers. p/c of (15%) gives maximum values of both tensile and compressive strength. 2the proposed model for polymer modified concrete (pmc) has a general form for all mixes. the constants change from mix to fit the shape of (p/ccompressive and tensile ) relations; and it is found from the second degree. 3the proposed model for compressive – tensile strengths is found as a straight line (first degree) equation and if we derive the equation then we can find 54.4== ft fc dx dy in general 4the improved mixes in this study did not submit to previous relations that gives the value of tension as a percentage from compressive strength. (ft/fc) [as we seen in paragraph(3)]. in this research the value (ft/fc) is found as (1/4.54), this ratio is bigger than the previous ratio (1/8 – 1/10) that indicate the (ft/fc) for ordinary concrete in previous studies. this perfect improvement in tensile strength make this type of (pmc) more useful and more economic for structural design and may lead to use less tension steel bars and make the construction more economic. al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 27 references: 1shetty, m.," concrete technology, theory and practice" s.chand and company, india , 3rd ed., 1988. 2vipulanandan ,c. and paul, w., "mechanical properties of epoxy and polyester polymers and polymer concrete systems, "aci mat.j., may-june 1990: 241-251. 3neville, a., "properties of concrete", 4th and final ed., london , 1995. 4ohama, y., "polymerbased admixture", cem. and conc. comp., 1998,20:189-212. 5radomir , j. and vlastimir, s."experimental research on polymer modified concrete ", aci mat.j., july-aug., 1998,:463-469. 6bentur, a., " properties of polymer latex – cement composites " the international .j . of cement composites and lightweight concrete , vol.4, no.1, 1982: 57-65. 7astm,c39/ c39m_ 01 standard test method for compressive strength of cylindrical concrete. 8ohama, y., " recent progress in concrete polymer composites" advn cem bas mat, new york, 1997: 31-40. 9sujjavnith, s.and lundy,j.," development of strength and fracture properties of styrene – butadiene copolymer latex – modified concrete ", aci journal, title no.95-m13.1998:131-143. table 1: grading of coarse and fine aggregates i.s sieve designation percentage passing by weight (%) indian standard (i.s) for grading(zone iii) 10mm 100 100 4.75mm 90 90-100 2.36mm 88 85-100 1.18mm 83 75-100 600micron 74 60-79 300micron 18 12-40 150 micron 2 0-10 table 2: chemical composition of sbr infra-red(i.r.)test ph% humidity content solid particles content % styrene butadiene rubber with small percentage of admixtures 8.2 42.4 57.42 al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 28 table (3): the effect of (p/c) on compressive strength of (pmc). p/c mix proportion p/c 0% p/c 5% p/c 10% p/c 15% p/c 20% p/c 25% 1:1.5:2 36.1* 67.8* 71.1* 83.3* 67.7* 65.3* 1:1.5:3 30.1* 48.3* 63.7* 76.1* 72.3* 68.0* 1:2:4 28.9* 40.2* 48.8* 60.3* 56.4* 51.7* * compressive strength in n/mm2(mpa) table (4): the effect of (p/c) on tensile strength of (pmc). splitting tensile strength (mpa) p/c mix proportion p/c 0% p/c 5% p/c 10% p/c 15% p/c 20% p/c 25% 1:1.5:2 4.4 9.9 11.3 13.9 12.7 12.5 1:1.5:3 3.5 5.8 7.6 10.3 10.8 10.6 1:2:4 3.0 5.2 6.8 9.7 9.5 9.4 tests compressive strength indirect tension test test for cylinders for cylinders figure (1) experimental program of this work al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 29 figure (3) the effect of the increase in (p/c) on compressive strength of (pmc) figure (4) the effect of the increase in (p/c) on tensile strength of (pmc) figure (2) effect of curing conditions on compressive strength for modified polymer concrete (5) al-qadisiya journal for engineering sciences vol. 2 no. 1 year 2009 30 figure (5) shows a mathematical model for the relationship between tensile strength and compressive strength for different mixes of pmc. 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 1 الحقل المغنطيسي لتحسين اداء اغشية المرشحات المستخدمة في استخدام منظومات تحلية المياه د. حسن شاكر مجدي مهدي شنشل جعفر * دكتوراه هندسة كيمياوية دكتوراه هندسة كيمياوية بابل –بابل عميد كلية المستقبل الجامعة –الجامعة كلية المستقبل mahdijaafar@yahoo.com hasanshker1@gmail.com 5106 كانون الثاني 7ُقبل في 5102 ايلول 8ستلم أ :الخالصة يأاممفتممفي مماياممحثيثستخممميثلممت اثفيثسطمماةيثسحد من لمم سيستخممايحممريثست لممتمئيةتممليثسح طممخمئيثسدطممم سي ثستممايت تتمم ي ثستجم بيتملت اثفيح ظ حمسييأج ئثسح ظ حس.ييأاثءةتلييلتتميححمي كسيثألغط س طلياحهييأ لتبي ايث لاثاي ثسح ظ حممسيسا ثلممسييإسمملت مضممايثس كلممايحممطيتلممت نيحجمممليحد من لممايةتممليحجمم يثسحمممءيثسمماث ليتن قممسيثستخت مم يي ثسحد لم فيحمري ثسكمسلم في يتك ت ممئثسقم ةيثسحد من لم سيةتمليتقت مليت لمبيثسحم ثايثسد م يثس ضم سيثسحتحثتمسييتأث -0111 ثلمت افيسذمحثيثسدم اييجذممايح مسجمسيحتد م يثسطماةيثسحد من لم سي ي مللي ضمايثس لم ةيستحممءيثسح ممس ت ظمم يثتةتتممم يح ممالييثأل ممححممطييةتممليتقت ممليثسحممرث ةيثسحد من لمم سيثسطمماةيتممأث ي(يكممم سيسح ممس0111-0111 ثلمت افيحممءيثسطم بيكحممءي مممفيي (يست /اق قمسي7-5-0-0ريثسحممءيخ مميتمفيثلمت اثفيةماةيح مماتئيستج ممر مج م %ي01-55ةلم ةيثسحممءيثسح ممس يت لمتسييث ضممايم يثستمايتمفيتلمج تذمييثسمليثستجم ب.يتط يثس تيإج ثءألغ ثاي ا ماةي لتسيثاثسسيثس ل ةي اييكم س.يكحميس خظيي(0111 _ي0111(تق حسية ايت ايثسحمءيثسليطاةيحد من ل سي خظي ج ايثثم يستت لتمئيثقملياث تايس ل يأغط سيثسح طايس يي حري لليتص يحقنط ح اتئيثسج مريثس مس س. ححميا يةت ي ايثسح طمخمئيثستمايسمفيتت م ايستحجممليثسحد من لما.ي مراايثلمت اثفيث يتلمت نيثسقم ةيثسحد من لم سي ت لمتمئيتسيثس ضماي لميةتمليreverse osmosis مايح ظ حممئيتخت مسيثسح ممهيثستمايت حمليتمست مضمايثس كلماي .ثس ح يثستطد تايسذميثنمسسا ماةيكضمءةيح ظ حسيثستخت سي ييةتليثتغط سي mailto:mahdijaafar@yahoo.com mailto:mahdijaafar@yahoo.com mailto:hasanshker1@gmail.com 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 2 ي ،يثست مضايثس كلا.ثس م سيثسح طخمئي،ةل ةيثسحمء،يثسح مسجسيأسحد من ل سي،تخت سيأسح مه:يالكلمات المفتاحية application of magnetic field to improve the performance of filter membranes used in water desalination systems abstract: membrane fouling is a serious problem facing the performance of water desalination systems. one of the most reason causing this fouling is water hardness as a caco3 due to the inorganic pollutants ca +2 and mg +2 in feeding water. this problem is the main object studied by this research by using the magnetic field applying various magnetic strong (1000-3000,6000) gause, to study the effect of magnetic field on reducing the membrane fouling through reducing the water hardness. results showed that at high magnetic strong led to increasing water hardness removal, that’s mean low fouling materials on the membrane. it was found that magnetic treatment reduce the water hardness to about 55-60% when 3000-6000 gause, magnetic field was applied and at level of water flow rate (7.0 l/min). the microstructure test showed that a fouling trace found on the membrane using in the control treatment unite compare with the filter membrane which applied the magnetic treatment technique. reducing membrane fouling rate enhancing water desalination unite efficiency and the membrane operating time. key words: desalination, magnetic treatment, water hardness, nanofilters, reverse osmosis المقدمة.0 ثسص مةاييةتليحلت ي تح تتفيأ ثةذمي أخجمحذميل ثءيح ظ حمئيثستخت سيثلت اثفأ تط ي ايثسل ثئيثأل ةي أصتاي ج اامي ايثسح مالييثسحث تسي ثألحلح مس سيحريثسط ث بييأ يثسح اسايستخص ليةتليح مهيصمسخسيستط ب ي يةتل يةحتذم ي ا يثسح ظ حمئ ياحه يت تحا يثسطم م. يثساقس ي م قس ي ح طخمئ يح ذم يثسدطم س ييي(ثسل ثح ك س goosen .et al, 2004) ) يتص طياحهيثأل ثعيحريثسح ظ حمئيستمح ري ايتصح فيي.ي قايخصليتن يكت يثسح ظ حمئيت ثج يت ايثسحطمكليثس م ي ايح ظفيةحت مئيثستصض سي إرياحه ي كحم يجحسثسنتبيثسحتاث ايةت ذم إسليحطمكليتطد ت سيث يتت تقيتمسظ فيثست سي مصسييتمإلضم سي,رينت سيثسح مهيثساث تسيإس ذمةتمأللمسي ةحت مئييحرت ثج ياحثيثس عييكت ةيحطكتسي خصلي ايثغط سيثسح طخمئي ثسحاي تت م يثسحايثسضطليث يثأل ذ يستح مه يثسيثستخت س ياحه يتلتت ييظما ةسحم ييحطمكلحر يجا س يترث يخلمتمئ يثسةتل ياحهييثتقتصما سجا سحثل إريتق مئيي(. busch k and busch m 1997 تقتليحريثس ح يثستطد تايستح ظ حسيثس حت مئ،يثحثيث ذمي تمجيح مهيثسط بي ايأصتخئيحريثستق مئيثس ل سيإلثسح طخمئيثسدطم سي مصسيح طخمئيثست مضايثس كلاي ثألغط سي تخمئي لليإ لاثايحريإري طليأغط سيثست ط ايتظذ يي(.(mohammadi et al,.2002يثس مسفي 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 3 kobe et يييج مريت ا ماةيحقم حتذميسيتلتبيت ثكفيثسح ثايثسحت لتسيةتليلنايثسدطمءي ثسضتخمئيثساث ت سيس al., 2001)ةاةية ثحليث يحتحثتسي ايإ ضمايح اليي تبيةتلياحثيثسضطلي ايأاثءيثسح طخمئ.يكحمي ت يثسنمقيثستا ق يإلتذلك ي ا ماة يثس ثطا ي ة س يألةتحما اثءة يتمس ظ ي ييخلمتمئيس ي ا يثسكتضس ح طخمئيث تمج ثريي حريثسكتضسيثستطد ت س(ي ت ي%30 – 20 تتا ليثسح طخمئي تضحريي كلايةتليثس ح يثستطد تاثست مضايثس ثس ح ييت يحريثس ثحليثأللمل سي ايتخل ر تيثسدطم سيثسح طخمئي اثسخايأ يثسل ن ةيةتليح اليثست لتمئي ح ظفيةحت مئيتخت سييثر.ي(fathi, 2006 ضايثسكتضسيتطكليةمفييثسحي كسيةتلييسذحهيثسح طخمئثستطد تاي ثسح مهيتلت افيأغط سيثست مضايثس كلاي ت تتفيةريثألغط سيثس م سيك ذميأغط سيغ يحلمح سي يث تقم سي تمجياحهيثس حت سيتخ ميتلحايسجا مئيثسحمءيتمسح ي قني ايخ ريتح طيح يثألحلحي ثسح ثايثسصتتسيثسحث تس,يتخ سصم اي قيثست ك ايت ريحك مئيثسحمءيثي ت يةرثتةت ماايثسحاي ا ايةريثسضدنيثسلافيستت مضاييثسليضدني خلبيقمةاةيثإل تطم ي إريثإل تقملي ك ريحريثست ك ايثألقليثسليثست ك ايثألةتلي س كسي يثسحمءيثسد يح مس ي ي نتقيةت يضدنيثست مضايثس كلاي احهيثس حت سي تنتبيتلت نيضدني ت ملبيحطيت ك ايثألحلحيثسحثت سي ا يحم banejad andثسحمءيحريثسجذسيحثئيثست ك ايثألةتليإسليثست ك ايثس ثنئ يثساي لمةايةتليا طيجا مئ ي abdosalehi, 2009ي(.ي ي,يكحم ايثغط سيثسح طخمئيcaco3 ح يثست لتمئيثستت سيسكم ت مئيثسكمسل فييترث يثسطاةيثسحد من ل سيةتلي %يختلي01ت لتسيثكث يحرييثريثست ايستض ايثسحد من لاي خايحريقمتت سييثسط ث بيثساق قسيثس مسقسيةتليثستكتل كحميثريثسطاةيثسحد من ل سيتا ايحريقمتت سيح تمري.ي(madsen 1995 يثسحجمتئيثسحد من ل سيثس ثن سيثسطاة اي ييتت اي.ي(qin, et al. 2009 يثسح مهيثتةت ما سيتح اليثكث يححميا يةت ي ايثتحلحي تختليثسخ ثحاي امي لليثس حت سي خينت سيثسح مهيثساث تسيأ يحميةريس متجيثسحت لتسييحريثسح ثاحريكث يثسح طخمئيغط سيث ييcaco3تطكليثسكم ت مئي ثسكت تمئي ي,ثستطد ت س ,caso4ي,baso4تلتبي ي,يحريثسحت لتمئي(ي لتسيةمس س لحليسيحطيلنايثتغط سييتقنتقسي ق قسيحتلصيحلتتسيحجذ سثسح مهيةتليثسح ثايثس ض سيتتك ريأخ مءييثخت ثء يثتخ م سثس يثسحتم حس ي(biofilmsينتقمئ ي( يثس لا يثسلتب ي مر يةمف يتطكل يا ييت لاثا يثتغط س ي طل أ تتأث يقمتت سيثسح طخمئيثسدطم سيي.(kozic et al, 2006 سيحك مئيثسحمءيل ثءيكم ئيةض سيأ يغ يةض إريل ةسيج مريكحميةتليكضمءةيثسح طخمئييحذفيتأث ثريستضدني ا جسيثسخ ث ةيثحيكث ثيتمسظ فيثستطد ت سي ي.(mohammdi et al,2002 يثسحمءيتلمةايةتلي ضايح اليثست لتمئيةتليثسدطمء ايت يثس قئي ثسكتفيحرييثسحد من ل سيثلت اثفيثسحجملة اييةتليت ايثستخل مئيثسحذحسححكريثسخص لي ضايثسنمقسيثستطد ت سيح مسجسيثسح مهيثسحتقاحسيحري لليي لليتقت لي ت ةيثلتتاثليثسح طخمئيث يثسص م سيثس محس ثنمسسيثس ح يثستطد تايستح طخمئي ثسح ظ حسي ثتلتد مءيةريثلت اثفيثسح ثاي ي يت ط ايثلتذلكيثسحمءييستح ظ حس يثس يثسك ح م س يثسخمحضا يثسدل ل يح ثئ يةاا ي تقت ص يستت ل ب يثجاثءي يحم س ي ا يثستمكل يح ال ضا (.يalimi et al, 2009ثسح ظ حس 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 4 :قة العمليطر .5 العكسي التناضحب لتحليةامنظومة ي: 0. 5 ييثلت احئ يثس كلا يتمست مضا يثستخت س يثج ثءح ظ حس ي ثسحتك ي ا يحرثستجم ب يتليتدح سي اثريس يلت كاحمء ,يتم ي0ثسح مهيتضدنييسا طي ضخاث سيح ااةييحض مئيحمءيسد ايح مسجتذم,ي ح ظ حسيسثيتدح سسستجح طي ح طخمئيكم ت سيستت تصيحريثسكت يقتليثسا ليثسليثسح طخمئي,يستت تصيحريثسط ث بيح طخمئي ل ج سي ثسل ن ةيةتليح اليسد اييتخكفي صحمحمئيث ي0/8ق مسييتللت ك سث مت بي,ييثسخقليثسحد من لا يثسدطم سي ي.(يثجاثءيح ظ حسيثسح مس يثسحلت احس0ثسطكل ي ت ريثسح مهي ايح ظ حسيثستخت سيرج م ي جهاز المعالجة المغناطيسية 1.1 حخت مممميحمممريقتمممليطيكمممم سيحصممم ي(0111 ي0111،ي0111ي حد من لممم سيحتد ممم يثسطممماةييسجذممممايح مسجمممثلمممت افي كمم ت ريحمريحمماةيثسيح ما ايغملف(يثجماثءيجذممايثسحد نمسيثسحلمت افي ثسحتكم ريحمري2 طمكلي ضايثس يثستمخث ري.ي يحثتتممسيةتممليثسذ كممليثس ممم جايت ثلممنسيحلممم ايح ا ممس.يتختمم ايةتممليحجح ةممسيحدممم ني،لممت لي يثسذ كممليثس ممم جا( ي حمممحجيةتممللممتنئيثلممت احئيقمم فيح تتضممسيحممريثسطمماةيثسحد من لمم سييثسخقممليثسحد من لمماي,ييا ثلممسيتمممث سدمم اي ي يةتممليثسحمم ثايثسحت لممتسيةتممليثغطمم سيثسح طممخمئيسح ممسيتمث اممم(كممم سي0111 ي0111،0111ثسح مممس يءثسحممم يثألغط س.يتتكيةتلي ضايثست لتمئيةتلحرث ةيطاةيث ضليتخا اي ي معالجة والفحوصات المختبرية طريقة ال5.3 : طريقة المعالجة. 5.3.0 جذمايح مسجسيثسطاةيثسحد من ل سيةتليثاثءيثغط سيثست ط اي ايح ظ حمئيثستخت سيتفيث ت م ييتأث سد ايا ثلسي يت ايثستجم بيتا ريتلت نثج ثءيييتمتضم سيثسليكم س,ي0111ي ي0111ي,0111ييحتد يثسطاةحد من ل سي يتأث ثتةتتم ييثت حيت ظ يحطيلمةسي(8,ي0,ي4,ي2 ح تتضسيضت ثئياح س سيطاةيحد من ل سي يتجم بيثسحقم س( يستدح سيثسح ظ حسي.يثلت افيحمءيثسط بثسحد من لايثستأث ي احطي جيح اليثسج مريةتليثاثءيث يكضمءةيثسح ظ حس ج ثء سح طخمئيت ثلنسيثفيض يثسليثحري يست يي21ريتللت كايل سي اي اثيتجح يث ت ثستجم بيخ مي تفي ث ج ثءت ايث تذمءيثس قئيثسحخااييتج تسيت ايكل حمحجييلختئي.تم يتق تمي0ضدنيت حليتيثسحض مئيثساث س ي ث .ح اثسثسضخ صمئيثس محسيستحمءيثسح مس ي ثسحمءي ي 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 5 الفحوصات المختبرية 5.3.5 ثج اي خصيةل ةيس حمحجيحريثسح يثساث تسيستح مسجسي حمحجيت ايثسح مسجسيسح سيثسض قيت ريثسق ث ت ري ا ثلسي ةحت سيثسح مسجس،ي تك ئي ن ةيثسضخصياحهيةتليكم سيثس محجي تتك ث يثلميتمث يثسطاةيثسحد من ل سيةتلي ح ثئيكلي خصي سكم سيح ثخليثسح مسجسيحطيثت حيت ظ يثتةتتم يحتد ثئيح اليثسج مري ثسطاةيثسحد من ل سي مءيحلي كحليثسخجفيتمضم سيثسحي51ة سيحريثسحمءي ايق سيخجح سيخجفييحلي01ثسحلت احس.ي تفيثسضخصيتم ح ،ثفيثض فيحقاث ي01حليحريحخت ليثستض يستك ريثساثسسيثثحض سيتلم ايي0.2ثسحقن ،يثفيثض فيثسليثس سي حريثساس ليثسحلت اححريحماةيثث ت رياثايت س ريثل تمئيثسحايتفيتخض هيحلتقمي حري لليثس لقسيثستمس سيي1.0 ي.تفيخلمبيثس ل ة th= a*n*1000 ,ml (1) th: total hardness(mg caco3 equivalent to 1.0 etda) a: ml of titration solution اث تسيسح ظ حسيثسح مهيثسيمبيثس لتسيثسح سيس ضايثس ل ةي ا حري لليتلج ليثس تم ي ثسق ثءثئيتفيخل ثسح مسجس ي011*%/يثس ل ةيثسكت سييثس ل ةيثسحتتق س(ي–ثس ل ةيثسكت سيي لتسيثاثسسيثس ل ةي=يييييييييي ي النتائج والمناقشة:.3 يثسح ضسيثسح طخسثسح مهييةتليح ثصضمئيثسح مهيثس متجسيسكليحريثج ئيثستجم بيتملت اثفيثسح ظ حسيثسح تت س ثس ل ةيةتليثلمسيكم ت مئيثسكمسل فيكحرط ي ثستايت تت يثس محليثس لايستت لتمئيثستاي لتسيثاثسسيي ثةتحائ يكم سي0111 ي0111،0111،ي1طاايحد من ل سيح تتضسيااييتفيتلت ني.ثسح طخمئتتجحطيةتليثغط سي ثسطكليي ت ري.ست /اق قسي8ثسليي2حرييح تتضسح اتئيج مريتيتجذ ايثسح مهث ت بيت ثلنسيجذمايحد نسي تنيحطي ثسلييثس مفثسطاةيثسحد من ل سي ايحج يثسح مهييتلتبيتمث ثسح ضسييثسح مهيح اليثاثسسيثس ل ةي اا ماةي(ي0 خ مي صتئي ايح ظ حسيثسحقم سيذحهيثسح مهيسي ل ةيثسيثاثسسح اليحقم سيتيح ظ حسيثست ط ايتمست مضايثس كلا %ي45احهيثس لتسيثسليي ث تض ئم س,يكي0111تحقاث يحد من ل سييثلت اثفيق ةية ا%ي08كضمءةيثتاثسسيثسلي حليثسحجمليي.كم سيي0111ييثلت اثفية ا%55 صتئيثسليكم سيي0111ثسحد من ل سيثسلييثسطاةيتا ماةي ستح مهيححمي لمةايةتليح طيت لبيثستكتلمئيثسحتحثتسيتمسك ت مئيةتلييثسحد من لايةتلي ضايثسطايثسلنخا .ي(gabrielli, 2001)ثتغط سيتمس غفيحريا ماةيةل ةيثسح مهيثسح ضس 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 6 تح مهيثسح مسجسيث ضميس يتمث ي ايثاثسسيثست لتمئيث يسيمركحسكي مريثس تم يثسحلجتسيتط يثسليثريا ماةيح اليثسج ستح مهي ثسحت ثممئي كم ريثقملي تمحسكيتيتتم ييت ايثري قئيثستقمءيثسج مريل ةسيثريثتغط سيثحثح طيتك ذميةتلي حممطيثتغطمم س.يثج ممئيتجممم بيث مم يسا ثلممسيتمممث ياحممريثستقمممءيث يثست مم اييقثتستصممم صممسيكم ممسيستت لممبيث ي يسحد من لم حمطيتلمت نيطماةييهنم ليثت تم بيثس مقمليستح مميا ممايسح ممهيثسح مسجمسيحمري مللستتث يثسحد من لايةتمليث (ي حسمكي ممت يةمري4%يكحممي تم ريثسطمكل 55إسمليط جايثريح اليثاثسسيثس ل ةيثسمليث تضم كم سيي0111تق حسييثمتتس سح مممسينت مممسيي.ة مممايا مممماةياحمممريثستقممممءثسقممم ةيثسحد من لممم سييتمممأث قمممايثااثايححممممي مممايا مممماةي احمممريتقممممءيثسح ممممهي يسكممل ت ممايثتلممت اثفيسألغطمم سيحجذ ممسيثستقنممئيصمم يحقن ممسثست لممتمئي ثت لمماثاثئي مماياث ممليثتغطمم سي قمماي تم رييسألغطم سةتمليثست ك مبيثسماث تاييسح سيتأث اممي جا ايثسحجمليثسحد من لايث يتا ايخمسسييرثسح ظ حت سح مسجممسييئثلممت احي ممايثغطمم سيثسح طممخمئيثستمماتت لممتمئيسيظذمم يثثممم يسألغطمم سثستصمم يثسحقن ممايي(5 يثسطممكل يييييييييييييييييييييييييييييييييييييييييييييييييييييييييهيثتةت ما س.محقم سيحطيتتكيثستايثلت احئيثسح يثسححد نسثسح مهي االستنتاجات.4 يثاثسممسيث يثس م ممسي لمممةايةتممل لممت افي ذممميثتغطم سي حممئيثست طمم ايثستممايظنت مقيثستق ممسيثسحد من لمم سي ممايح تثري نمسمسكضمءةيثسح ظ حسييثغط سيثسح طخمئي احثي ااةتلييثست لتمئح اليضاي يثس حم يثستطمد تايستح طمخمئي ي ث ااثايح اليثاثسسيثس لم ةيحمريثسح ممهيثسح مسجمسيي، تمستمسايا ماةيثسجا يثتقتصما سيستح ظ حسيثستطد ت سنمقسيثستقت لي ثستقمءيستح ممهييكم سي ة ايثلت اثفي ضسيثسطاةي ا ماةياحري0111%ية ايتلت نيطاةيحد من ل سيحقاث امي45ثسلي ثاثءيةحت مسيثست طم اييتخلمر%.ياحهيثس تم يتت ريثريتنت قيثستق مسيثسحد من لم سي55ثسح مسجسيث تض ئيثس لتسيثسلي يةت مااثثسح طخمئيسضت ةيثن ليححميس يثلت احئيتطكلي ثسخضمظيةتلي references: [1] alimi f., tili m.m., ben amor, m., maurin, g., gabrielli c. (2009) effect of magnetic water treatment on calcium carbonate precipitation: chemical engineering and processing, vol. 48, issue 8 (august 2009),pp. 1327-1332, issn 0255-270 [2] banejad h. abdosalehi b., (2009), the effect of magnatec field on water hardness reducing , thirteenth international water technology conference, iwtc 13 2009, hurghada, egyp. [3] busch kw, busch mbm (1997). laborator studies on magnetic water treatment and their relationship to a possible mechanism for scale reduction. desalination, 109(2): 131. [4] ebrahim, s. (1994). cleaning and regeneration of membranes in desalination and wastewater application: state-of-the-art. desalination, vol. 96, issues 1-3, (june 1994), pp. 225-238, issn 0011-9164 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 7 [5] fathi, a.; t. mohamed, g. claude, g. maurin and b. mohamed, )2006( effect of a magnetic water treatment on homogeneous and heterogeneous precipitation of calcium carbonate. water research, 40, pp: 1941-1950,. [6] gabrielli, c., jaouhari, r., maurin, g., keddam, m. )2001( magnetic water treatment for scale prevention. water res. 35 (13), 3249-3259,. [7] goosen, m.f.a.; sablani, s.s.; al-hinai, h.; al-obeidani, s.; al-belushi, r.&jackson, d. (2004). fouling of reverse osamosis and ultrafiltration membranes: a critical review.separation science and technology, vol. 39, no. 10, pp. 22612297 ,issn 0149-6395 [8] kobe, s.g. drazic, p.j. mcguiness, j. strazisar, )2001(, the influence of the magnetic field on the crystallization form of calcium carbonate and the testing of a magnetic water-treatment device, journal of magnetism and materials, 236:71-76,. [9] kozic v., krope j., lipus l. c. ( 2006), magnaetic field analysis on electromagnetic water treatment device, hngarian journal of industria chemetry m vol 34 pp 51-54, veszprem. [10] madsen l. h.e., (1995). influence of magnetic field on the precipitation of some inorganic salts.j. cryst. growth 152,94-100, [11] mohammadi, t.; madaeni, s.s. moghadam, m.k. (2002). investigation of membrane fouling. desalination, vol. 153, issues 1-3, (february 2003), pp. 155160, issn 0011-9164 [12] qin, j.j. liberman, b. kekre, k.a. (2009). direct osmosis for reverse osmosis fouling control: principles, applications and recent developments. chemical engineering journal, vol.3, no. 1,pp. 8-16, issn 1874-1231. 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 8 يثجاثءيح ظ حسيثسح مس يثسحلت احسي:(0)رقم الشكل ح طاي ل جاي.2حض سيضدنيةمساي .reverse osmosisح ظ حسيثست ط ايتمست مضايثس كلاي ت سيثستخت سيتمست م حي.0 اثريثستدح سيي.5ح ظ حسيح مسجسيحد من ل سي.4ح طايكم ت ريح طني.0 ي(roثس كلا -4تغذية الماء)دخول الماء( -3الجزء الثابت -2الجزء المتحرك جذمايح مسجسيحد من ل سيحتد يثسطاةي:(5) رقم الشكل يخروج الماء المعالج( 1 2 3 4 6 5 1 1 3 4 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 9 ييحريثغط سيثست ط اي ايج مريةتليثاثسسيثس ل ةيتمث يثسطاةيثسحد من ل سي ح اليثسي(:3)رقم الشكل ثست مضايثس كلا ي ي ي ي ح ظ حسيثست مضاييثاثسسيثس ل ةيحريثغط سيثست ط اي اةتلييتقمءيثسح مهيثسح مسجستمث ياحريي:(4)رقم شكل يثس كلا 0 10 20 30 40 50 60 0 1 2 3 4 5 6 7 8 t o ta l h a rd n e ss r e m o v a l% flow rate, l/min m.f=1000 g m.f=6000 g m.f=3000g m.f= 0.0 g 0 10 20 30 40 50 60 0 2 4 6 8 h a rd n e ss r e m o v a l e ff % flow rate l/min mf= 6000g single pipe mf= 6000g trible pipe 6101 1العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 ي-. يأ ايثسح مسجسي كم س(ص يحقن سيحكت ةيسلغط سيقتلي ت ايثلت اثفيثسق ةيثسحد من ل سيي:(2)رقم الشكل ثسطاةيي-,يا0111,يج_يثسطاةيثسحد من ل س=ي0111ثيسطاةيثسحد من ل س=ي-,يبي1.1ثسطاةيثسحد من ل سي= ي(ي0111ثسحد من ل س,ي د ب ج أ al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 366 effect of copper addition on the microstructure and mechanical properties of al-si alloy yasir muhi abdulsahib assistant lecturer department of production engineering & metallurgy university of technology iraq email: yaser_msc2010@yahoo.com received 17 june 2014 accepted 17 september 2014 abstract aluminum alloys are very important in many industrial applications because of their lights weight and good mechanical properties. there is a great need to recycle the metals and alloys used in the metallurgical industry and various engineering applications, particularly aluminum alloys due to their low melting point and usefulness. in this work, the effect of copper wires addition with different percent on the microstructure and mechanical properties of al-si alloy (piston part as a scrape) were studied. tensile test, hardness, microstructure sem and xrd were conducted .the results showed that the addition of copper to the alloy (al-12wt%si) have improved its mechanical properties (tensile strength, yield strength and hardness) also changed microstructure of al-si alloy as compared with the base alloy. keywords: al-si alloys, mechanical test, microstructure. .al-siاص الميكانيكية لسبيكة تأثير اضافة النحاس على البنية المجهرية والخو ياسر محي عبد الصاحب مدرس مساعد الجامعة التكنولوجية قسم هندسة االنتاج والمعادن الخالصة هنالك .جيدةالميكانيكية ال االخفيف وخصائصه الصناعية بسبب وزنهسبائك األلومنيوم مهمة جدا في العديد من التطبيقات اتعتبر ر المعادن والسبائك المستخدمة في الصناعات المعدنية والتطبيقات الهندسية المختلفة، وخاصة سبائك حاجة ماسة إلعادة تدوي على شكل اسالك في هذا البحث تم دراسة تاثير اضافة معدن النحاس .اواستخداماتهاأللومنيوم بسبب درجة انصهارها المنخفضة اراتيساللمكائن مكابس احتراق داخلي اخذت منوالتي al-siلسبيكة على البنية المجهرية والخواص الميكانيكة بنسب مختلفة و فحص حيود االشعة السينيةتم اجراء اختبار الشد والصالدة وكذلك فحص البنية المجهرية باستخدام المجهر الضوئي .)خردة( قد حسنت الخواص al-12wt%si الى سبيكةالنحاس اضافة بينت النتائج ان .المجهر االلكتروني الماسحالفحص باستخدام و مقارنة بالسبيكة االساس. البنية المجهرية ترتغيوكذلك الميكانيكية )مقاومة الشد, مقاومة الخضوع والصالدة ( mailto:yaser_msc2010@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 367 introduction in recent years, the plenty of waste of aluminum alloys increase, therefore as replacing primary alloys are secondary (recycled) aluminum alloys used. application of secondary aluminum alloys is important, because the production of primary aluminum alloys consume about 45 kwh/kg of metal and the production of secondary only about 2.8 kwh/kg of metal. it is to the aluminum industry’s advantage to maximize the amount of recycled metal, for both the energy-savings and the reduction of dependence upon overseas sources. utilization of secondary aluminum alloys increase in recent years also due to their comparable properties with primary aluminum alloys [1, 2]. aluminium-silicon based alloys are well-known casting alloys with high wear resistance, low thermal expansion coefficient, outstanding castability, together with their low specific weight, good corrosion resistance, and improved mechanical properties in a wide range of temperature. these properties lead to an increasing the applications of al-si alloys in automotive industry, especially for cylinder blocks, cylinder heads, pistons and valve lifters [3, 4]. the automotive and aircraft industrial needs led to increasing application of al-si cast alloys thanks to the great potential of these materials as replacements for heavier materials (steel, cast iron etc.) [5, 6, 7]. these alloys have between 10 and 13% silicon, and consist mainly of al-si eutectic in the cast structure [8]. the mechanical and microstructural properties of aluminum cast alloys depend on the composition; melting conditions, solidification rate, casting process and the applied thermal treatment [1, 9]. mechanical properties of al-si alloys are of course related to the morphology of silicon particles (size, shape and distribution), al grain size, shape, and dendrite parameters [10]. the presence of additional elements in the al-si alloys allows many complex intermetallic phases to form. copper is a potent precipitation-strengthening agent in aluminum. cu additions up to about 5% lead to alloys with high strength and good toughness when subject to natural or artificial aging. the addition of cu increases considerably the strength of al–si alloys, due to precipitation of dispersed al2cu (θ) phase during aging. the strengthening contribution from precipitation is typically a function of both precipitate size distribution and volume fraction [11]. in the applications where ductility is not of prime importance such as cylinder head, cu containing variants of these alloy have the distinct advantage of increased strength at high temperatures and therefore are becoming increasingly popular. this alloy is mainly used in casting engine blocks, cylinder heads, pistons and manifolds [12, 13]. the presence of alloying and impurity elements such as (cu, mg, mn, fe etc.) leads to more complex constituents (including intermetallic compounds) that are characterized by metallographic consequence [14]. several studies of al-si casting alloy have different factors that affect on microstructure and chemical properties, hurtalová et al (2012) [1] were studied the effect of chemical composition of al-si cast alloy on intermetallic phases, changes of chemical composition of al-si cast alloys led to formation different intermetallic phases in these cast alloys. c. h. caceres et al (2003) [13] were studied the effect of different contents of elements on al-si-cu-mg casting alloy, the strength of alloys increases with increasing content of mg and /or cu. in all cases the ductility decreases as well. a higher content of fe generally reduces the strength and ductility. the present work focused on evaluating the effects of the addition of various amounts of copper (0, 1, 2, and 3 wt. %) on mechanical properties (tensile test, hardness, and ductility) and microstructure of recycled pistons alloy (al-12wt%si). al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 368 experimental work the materials used in this work were aluminum – 12wt% silicon alloy (recycled piston part), the chemical composition is shown in table (1), and wires of copper. the chemical composition analysis was carried out using (dissolution spectrometer) in a state company for examination engineering and qualification (specialist institute for mechanical industry, previously). a 200 gm. of recycled piston alloy was cut into smaller pieces and melted using graphite crucible in an electrical furnace at 750 °c as shown in figure (1). after melting, one sample was poured without additive, and three other different weight percentages of copper wire were added to the molten alloy (1, 2, and 3 wt.%) the melt is stirred by electrical stirrer using steel rod for 30 seconds to ensure the homogeneity of the molten alloy. argon gas with flow rate of 1s milliliter/min was used from the beginning of melting process to reduce the oxidation. after the stirring process, the temperature was raised up to 1000 °c and fixed for 15 min to ensure partial melting of the cu wires. the homogenized melt was poured in a preheated stainless steel die with dimensions of (17 mm) diameter and (120 mm) length. 1. tensile test the tensile specimen’s dimensions were produced according to astm-e8 as shown in figure (2). they were tested by an instron machine with a (20) ton capacity and (1) cm/min cross head speed. tests were performed at ambient temperature on smooth specimens at a stress ratio r= -1. where: g: gage length = 45mm. d: diameter = 9 mm r: radius of fillet = 8 mm a: length of reduced section = 54mm. the mechanical properties (tensile strength, 0.2% proof strength, % of elongation, % of area reduction, and h.v) were evaluated. from stress – strain curve, the values of tensile strength (σt), strain (ϵ) and yield strength (by taking the 0.2% of the strain (as a proof strain)) were found for each alloy [15]. the area reduction percent is calculated from the following relationship [16]: r.a % = (ao – a) / ao (1) to find a for equation: ao * lo = a * l (2) to find l for equation: strain (ϵ) = (l – lo) / lo (3) where: r.a: reduction area (mm 2 ). ao: original area (mm 2 ). al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 369 a: final area (mm 2 ). lo: original length (mm). l: final length (mm). 2. hardness test. vickers macrohardness was measured using diamond pyramid indenter with applied load of 200 gm. for 15 second endurance to measure the hardness (five hardness values were taken for each sample). 3. microstructure examination specimens of 5 mm height, and 10 mm diameter were prepared from the section rods, which were left after study the microstructure. one surface of all specimens were initially grinding using a series of waterproof sic papers (220, 320, 500, 800, 1000) with increasing fineness to remove any of the scratches present through the cutting or any previous process. finally polishing was carried out on a disc polisher using diamond pastes of 1 µm particle size with polishing liquid as a cooling lubricant until the mirror like i.e. scratch free surface was obtained. polished samples were cleaned with distilled water and alcohol. the prepared samples were etched using keller’s solution for about 30-50s in order to reveal the microstructure with grain boundaries and finally, the polished specimens were taken for optical microscopy. the microstructure of the test samples was examined by optical microscope (100w carlzeiss jane, germany, ep. type 2) connected to digital camera. 4. scanning electron microscope test. microstructural characterization studies were done to observe the microstructure of sample surface test. this is done by using scanning electron microscope. characterization is done in etched conditions. etching was done using the keller’s reagent (1 volume part of hydrofluoric acid (48%), 1.5 volume part of hydrochloric acid, 2.5 volume parts of nitric acid and 95 volume parts of water). the samples were characterized by (angstrom) scanning electron microscope (sem) in nanotechnology and advanced materials research center / university of technology. 5. x-ray diffraction (xrd) test. x-ray diffractometer shimatzo 6000x was used to study the phase composition of the al12wt%si alloy, with measuring condition as below. this test was done in a state company for examination engineering and qualification. target: cu, wave length= 1.5406 a o , 2theta range= 0-80 deg. results and discussion microstructure microstructural characterization studies were done to observe the microstructure of sample surface test. this is done by using scanning electron microscope. characterization is done in etched conditions. etching was done using the keller’s reagent (1 volume part of hydrofluoric acid, 1.5 volume part of hydrochloric acid, 2.5 volume parts of nitric acid and 95 volume parts of water). al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 370 figures from (3-6) shows the scanning electron microscope of al-12wt%si alloys without and with additives, figure (3) show the sem of al-12wt%si as cast. see figure (3), higher levels of si is observed at the edge of the dendrite, which are also generally having higher overall si concentrations have coarser microstructures. the result is in agreement with l. pedersen et al (1998) [17] and a. l. dons et al (1999) [18] and lately confirmed by hardness measurement confirmed by seifeddine et al (2007) [9]. for the slowly solidified materials, si could be diffused from the α-al matrix to si particles in the eutectic after solidification. this finding explains further the coarsening and formation of si bands around the dendrites. the segregation profiles cu are shown in figures 4, 5 and 6. as the cu levels are increased, coarseness of phases such the al2cu phase, embedded in-between the dendrites, both as blocky and as eutectic to be increased, from figure showing. numerous work has been performed on the distribution and location of these cu-bearing intermetallic and the current study can only confirm these findings [20]. the reason for the increased coarsenesses of cu-bearing intermetallics, along with increased cu additions could be explained, besides the time available for growth, by the ability of the matrix to host elements, as clearly observed in figures 4, 5 and 6. the cu concentrations in the dendrites seem to be slightly influenced by the solidification rate, with a higher cu concentration at the dendrite centre and edge for coarser microstructures, which is also supposed to be a result of back diffusion due to the longer solidification time. cu concentrations in the centre of the dendrites have been reported in the literature, but these results show some variations qian et al (2003) [21] and sjölander et al (2011) [20]. generally, as cu is added, a ternary eutectic reaction at about 525˚c will occur leading to shrinkage that will not be compensated. besides, the sample hydrogen activity coefficient might decrease with increasing cu content and hydrogen solubility decreases, leading to increased porosity [22]. however, there is a direct relationship between the copper content and the reduction in the grain size diameter which it related to the enhancement of the mechanical characteristics of al-12wt%si. the microstructures of al-12wt%si-cu casting alloy are essentially consist of three components; the two main components are primary α-al solid solution phase and al-si eutectic, the third component is intermetallic phases which have the important factor improvement on the mechanical properties of alloys [1, 13]. figures (7-01) shows the optical microstructure of al-12wt%si alloys with different additions of copper. from the figures, homogeneous distribution of the primary silicon particles was clear. figure (7) shows the microstructure of al-12wt%si alloy without any addition, which consists of the eutectic silicon as acicular flakes, α-aluminum matrix and the primary silicon particles, figure (00) illustrated the xrd pattern of al-12wt%si alloy which shows the peaks of al and si. figure (8) shows the microstructure of al-12wt%si alloys with 1% copper, also consist of primary silicon particles, α-aluminum matrix, eutectic silicon and intermetallic phases of al2cu. figure (9) shows the microstructure of al-12wt%si with 2wt% copper; which consists of the eutectic silicon as acicular flakes, α-aluminum matrix, the primary silicon particles and some intermetallic particles of al2cu. figure (01) shows the microstructure of al-12wt%si with 3wt% copper, which consist of the α-aluminum matrix, and intermetallic particles of al2cu, figure (01) illustrated the xrd pattern of al-12wt%si-3wt%cu alloy which shows the peaks of al and si and al2cu. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 371 as is known, copper is partially soluble in α – al solid solution with a maximum solubility of 5.65 wt% at 550 °c. for alloys with al to from 1 to 4 wt% copper, cu-rich intermetallic phase (al2cu) typically form in the structure [12]. al-si alloy usually contains a little amount of iron, which plays an important role in the nucleation of the eutectic si in these alloys. tensile & hardness test results table (2) illustrates the mechanical properties of al-12wt%si recycled alloy without and with different copper additions. after melting and pouring of the recycled alloy, it was found that the tensile strength is (111 mpa) where this value represents the tensile strength of piston recycled alloy (al-12wt%si) without any additives, and when adding different amounts of copper to the recycled alloy we notice an increase in tensile strength with increases copper additives percent to the al-12wt%si and with higher tensile strength value was (172 mpa) at 3wt% of copper. we notice that 1 wt% of copper added to the base alloy causes a significant increase in the tensile strength as compared to the base alloy more increase was found with 2 and 3 wt% of copper. also the yield strength increases with increase the copper content and maximum yield strength (49 mpa) at 3 wt% of cu. mechanical properties of the alloys depend on the shape, size and distribution of eutectic silicon, α-al grains/dendrites and the presence of alloying element in case of al-si alloys. the results of the hardness of the al-12wt%si alloy with copper lead to a clear increase in the values of hardness as compared to the base alloy hardness value under the same conditions. the reasons for increasing the hardness in this case is the creation of intermetallic compound phase al2cu. table (2) showed the vickers hardness of the base as well as other alloys with copper additives. it’s found that higher hardness values (66.5 h.v) were obtained with 3 wt% of copper additives as compared with base alloy is value (34.7 h.v). figures (13-17) show the influence of percentage copper on mechanical properties of al12wt%si. the tensile strength, yield strength and hardness increase with the increasing copper content as compared with base alloy through the formation of intermetallic phases. the improvement in the mechanical properties such as tensile strength, yield strength, and hardness as compared with base alloy (al-12wt%si) is due to cu addition. the ductility however (elongation and area reduction decrease with increasing copper additions. the elongation and reduction area are (6.2%) (5.48%) while these values decrease with increasing copper content. the presence of copper in alloy may be produces intermetallic compounds and this phase impeded the movement of dislocations, as a result the alloy has high tensile strength and hardness. mechanical properties of al-12wt%si recycled alloy dependent on the shape, size and distribution of particles (intermetallic compounds) in the resulted alloy. conclusion 1. from the scanning electron microscope, the addition copper in al-12wt% alloy change the microstructure from coarse structure to fine structure. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 372 2. the mechanical behavior of al-12wt%si recycled alloys increased with increasing copper content. the tensile strength, yield strength and vickers hardness increased with increasing copper content. while elongation and reduction area decrease with increase the copper additions to base alloy. 3. the presence of alloying elements such as (cu, fe, mg, mn) leads to formation intermetallic compounds, presence al2cu phase in microstructure strengthening the al12wt%si alloy. 4. it possible take advantage of the materials or alloys (scrap) by re-melted and the addition of some of the elements that alter mechanical properties and uses in suitable engineering applications. references [1] hurtalová l., prof. tillová, e., chalupová m., ďuriníková e., “effect of chemical composition of secondary al-si cast alloy on intermetallic phases”, faculty of mechanical engineering university of žilina in žilina, the slovak republic, pp. 11-14, 2012. [2] hurtalová l., e. tillová, m. chalupová: “optical and electron microscopy study of the mechanical properties improvement on recycled alsi9cu3 cast alloy along the hardening”, mtm, vol. 7/2011, pp. 48 -51, 2011. [3] muzaffer zeren, erdem karakulak, and serap gümüş, “influence of cu addition on microstructure and hardness of near-eutectic al-si-x cu-alloys”, trans. nonferrous. met. soc. china, vol. 21, pp. 1698-1702, 2011. [4] a. hossain, a. s. w. kurny “optimization of artificial ageing time and temperature on evaluation of hardness and resistivity of al-si-mg (cu or/& ni) alloys”, international journal of chemical, materials science and engineering vol: 8 no: 4, 2014. [5] hamilta de oliveira santos, marilene morelli serna, nelson batista de lima, isolda costa, jesualdo luiz rossi, “crystallographic orientation-spray formed hypereutectic aluminium silicon alloys” , materials research, vol. 8, no. 2, 181-186, 2005. [6] wang e. r., x. d.hui, s. s.wang, y. f.zhao, g. l.chen, “improved mechanical properties in cast al-si alloys by combined alloying of fe and cu”, materials science and engineering a 527, pp. 7878-7884, 2010. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 373 [7] samuel a. m., f. h. samuel, h. w. doty, “observation on the formation ß-al5fesi phase in 319 type al-si alloys”, journal of materials science, 31, pp. 5529-5539, 1996. [8] geoffrey k. sigworth “fundamentals of solidification in aluminum castings”, international journal of metal casting / volume 8, issue 1, 2014. [9] seifeddine s, “the influence of fe on the microstructure and mechanical properties of cast alsi alloys”, literature review vilmer project. jönköping university, sweden, 2007. [10] s. a.jenabali jahromi, a. de hghan and s. malekjani, “effects of optimum amount of sr and sb modifierson tensile, impact and fatigue properties of a356 aluminum alloy”, iranian journal of science & technology, transaction b, vol. 28, no. b2. shiraz university, 2004. [11] muzaffer zeren and erdem karakulak, “study on hardness and microstructural characteristics of sand cast al–si–cu alloys”, bull. mater. sci., vol. 32, no. 6, december, pp. 617–620. © indian academy of sciences, 2009. [12] a.m. samuel and f. h. samuel, “a metallographic study of porosity and fracture behavior in relation to the tensile properties in 319.2 in chill casting” , metal matter trans. 26a pp.2359-2372, 1995. [13] c. h. caceres, i. l. svensson, j. a. taylor, “strength – ductility behavior of al-si-cu-mg casting alloy in t6 temper”, school of engineering, the university of queensland, brisbane qld 4072 australia. int. j. cast metals res., 15, pp. 531-543, 2003. [14] l.a. dobrzański, r. maniara, j.h. sokolowski, “the effect of cast al-si-cu alloy solidification rate on alloy thermal characteristics”, journal of achievements in materials and manufacturing engineering, volume 17 issue 1-2, july-august, 2006. [15] william d. callister, jr, “materials science and engineering”, department of metallurgical engineering the university of utah, seventh edition, p 134, 2007. [16] peter a. thornton & vito j. colangelo, “fundamentals of engineering materials”, u.s. army research and development center watervliet, n.y. pp. 230-231. 1985. [17] l. pedersen and l. arnberg, “anomalous microsegregation in al-si foundry alloys” , materials science and engineering a, vol. 241, no. 1-2, pp. 285-289, 1998. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 374 [18] a. l. dons, l. pedersen and l. arnberg, “the origin of ‘anomalous’ microsegregation in alsi foundry alloys— modelling and experimental verification”, materials science and engineering a, vol. 271, no. 1-2, pp. 9194, 1999. [19] s. seifeddine, s. johansson and i. l. svensson, “the influence of cooling rate and manganese content on the al5fesi phase formation and mechanical properties of al-si-based alloys” , materials science and engineering a, vol. 490, no. 1-2, pp. 385-390, 2008. [20] e. sjölander, “heat treatment of al-si-cu-mg casting alloys,” ph.d dissertation, chalmers university of technology, gothenburg, 2011. [21] m. qian, f. yi, d. zhang, x. pan, h. d. brody and j. e. morral, “solute distribution and phase appearance in as-cast al-si-cu-mg-fe alloys” , asm international, pittsburgh, pp. 69-78, 2003. [22] s. g. shabestari and h. moemeni “effect of copper and solidification conditions on the microstructure and mechanical properties of al-si-mg alloys”, journal of materials processing technology, vol. 153-154, pp. 193-198, 2004. table (1): the chemical composition of the (al-12wt% si) recycled alloy. si pb mn mg zn fe cu ni cd sn ti al 12.09 0.261 0.107 0.069 0.346 0.787 0.34 0.654 0.389 0.13 0.105 balance table (2): effect of different cu wire additions on mechanical properties of (al-12wt%si) recycled alloy. alloy no. alloy type tensile strength (mpa) yield strength (mpa) strain hardness hv elongation % reduction area % 1 al-12wt%si 111 20 0.062 43..43 6.2 5.84 2 al-12wt%si +1wt%cu 541 32 0.0195 45.788 1.91 1.62 3 al-12wt%si +2wt%cu 166 44 0.0586 74.0.3. 1.37 1.14 4 al-12wt%si +3wt%cu 172 49 0.0576 66.5356 5.76 5.45 al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 375 figure (1): illustrated the melting process. figure (2): shows the standard astm-e8 of tensile specimen test. figure (3): sem for al-12wt%si alloy. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 376 figure (4): sem of al-12wt%si-1wt%cu. figure (5): sem of al-12wt%si-2wt%cu. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 377 figure (6): sem of al-12wt%si-3wt%cu. figure (7): as received microstructure of al-12wt%si alloy. α-al primary si particles 100 µm eutectic 125x al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 378 figure (8): microstructure of al-12wt%si-1wt%cu. figure (9): microstructure of al-12wt%si-2wt%cu. 100 µm primary si particles α-al eutectic al2cu 125x 100 µm α-al al2cu primary si particles 125x al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 379 figure (01): microstructure of al-12wt%si-3wt%cu. figure (00): xrd pattern for al-12wt%si recycled alloy. figure (01): xrd pattern for al-12wt%si-3wt%cu alloy. al2cu dendrite 100 µm 250 x al si al al al si si al al si al al al si si al al2cu al2cu al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 380 figure (13): shows the effect of copper addition on tensile strength of al-12wt%si alloy. figure (14): shows the effect of copper addition on yield strength of al-12wt%si alloy. figure (15): shows the effect of copper addition on hardness of al-12wt%si alloy. al-qadisiya journal for engineering sciences, vol. 7……no. 4 ….2014 381 figure (16): shows the effect of copper addition on % elongation of al-12wt%si alloy. figure (17): shows the effect of copper addition on % reduction area of al-12wt%si alloy. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 279 new finite difference derivation for calculation of natural frequency of sector steel plate dr. sadjad a. hemzah civil engineering department college of engineering, university of al-qadisiyah al-qadisiyah, iraq e-mail: sah246@gmail.com received 1 march 2016 accepted 17 april 2016 abstract a free vibration analysis of isotropic thin circular plate with various edge conditions have been studied in the present work. this study involves the obtaining of natural frequencies by solving the mathematical model that governs the vibration behavior of the plate using finite difference method. the numerical results of natural frequencies of circular plate are presented for different cases such as aspect ratio, curvature effect, grid size and boundary conditions. a good results was obtained from finite difference procedure compared with that obtained from the finite element analysis using abaqus package program. keywords: curved plate, free vibration, thin plate, finite deference analysis , numerical analysis. اشتقاق جديد بطريقة الفروقات المحددة لحساب التردد الحر للصفائح الحديدية المنحنية الخالصة ملت الدراسة اشت. النحيفة الدائرية الصفائح تحليل في المحددة الفروقات طريقة حساب االهتزاز الحر باستخدام دراسة البحث هذا في تم النتائج المتحصلة من .الفروقاتطريقة على ايجاد االهتزاز الحر من خالل حل المعادالت الرياضية الخاصة للصفائح المقوسة باستخدام , درجة التقوس , حجم التقسيم العرض الى الطول نسبةالتحليل باستخدام طريقة الفرقات المحدةة لهذه الصفائح ولحاالت مختلفة مثل العناصر طريقة من المتحصلة النتائج مع جيدا توافقا المحددة الفروقات طريقة من المتحصلة النتائج أعطت . وع المساندللصفيحة و ن .الدراسة هذه ضمن المأخوذة المتغيرات أنواع ولكافة abaqus برنامج وباستخدام المحددة .الفروقات المحددة ,التحليل العددي طريقة، األلواح النحيفة ، التردد الحراأللواح المقوسة ، كلمات البحث: 1. introduction mailto:sah246@gmail.com al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 280 plates, as structural elements, are extensively used in many fields of engineering including aerospace, civil structures, hydraulic structures, containers, ships, instruments, and machine parts. when in service, they are subjected to dynamic loadings the effect of which is very critical. much research has been conducted into plate behavior, using a wide range of methods. an excellent monograph of the early literature relating to vibration analysis of plates was published by leissa [1] . the small thickness makes the plate susceptible to various types of effective such as buckling modes and vibration modes. in engineering application, however, plate problems often involve consideration of dynamic disturbances, produced by time-dependent external forces or displacements. dynamic loads may be created by moving vehicles, wind gusts, unbalanced machines, etc. most researchers [1][2][3] , have used classical thin plate theory in their formulations to study the plate response; where the flexural vibration of the thin plate is characterized by a fourth-order partial differential equation. a direct solution of such equation might be difficult and most of the reported solutions are based on numerical methods such as finite difference method [4,9] , and finite element method [4], [5] . a number of approaches were proposed by different researchers to solve the differential equation of plats. finite element and finite difference methods are the well-known approaches to be the most widely used numerical procedures to find the solution of the mentioned differential equation. finite element method advantageous is that it is very suitable for practical engineering problems of complex geometries. however, the computational complexity involved in this method constitutes the main disadvantage of this technique, especially in real-time application. on the other hand, the method is fast enough to analyze, relatively easy to program, and also seems to be more convenient for uniform structures such as plate system. the main serious impediment of this method is that it is not suitable for problems with complex and irregular. moreover, since the finite difference method is difficult to vary the size of the difference in particular regions, it is not suitable for problems with rapidly changing variables such as stress concentration problems. however, because of the geometry uniformity of the thin plates, finite difference method seems to be more applicable and faster to calculate deformations, forces, stresses and strains and natural frequencies. the objective of the present study is to develop an accurate and efficient method for determining the natural frequencies of isotropic curved thin plate with different boundary conditions, aspect ratios, curvature and grid size. 2. description of the problem the curved plate considered in this study is an isotropic plate with constant thickness (h) and has an inner radius rin and outer radius rout as shown in fig. (1). the circular plate divided by a polar mesh. the interval of mesh in the direction of the radius is (β), while (φ) is the angle of each interval of mesh in the direction of central angle, the interval between the nodes in the perpendicular direction on the radius is denoted as (γ i-1 , γ i , γ i+1). 3. governing equations and finite difference formulation and solution the governing equation of motion in polar coordinate for a curved isotropic plate of uniform thickness and without in plane load is [7] : al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 281 where: q= is distributed load applied on the plate surface ρ= density of the material h= thickness of the plate d= flexural rigidity these variables could be expressed as follows: therefore, the final governing equation of motion of isotropic circular plate will be as follows: the solution of equation ( 4 ) may be accomplish by finite difference method, as shown in fig. ( 2 ) : where: λ = ω 2 . ρ.h al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 282 by applying the finite difference scheme at the interior nodes of the divided plate, the following system of simultaneous linear equations in matrices will be obtained [ 6 ] where{w} is column matrix whose elements, ωi, represent the amplitude of the free vibration, [ k] is a square matrix obtained from the finite difference expression of the biharmonic operator , while[b] is a diagonal matrix representing the constants in the term of eq. (7), and λ= ω2.ρ. notice that eq (7) is an eigen-value problem. for a given thickness (h) and plate–aspect ratio a b (b= radius* substantial angle(rad)), the eigen-value (ω) can be determined numerically by using any relevant technique. the smallest eigen-value gives the most (fundamental) free vibration factor. 4. the eigen-value problem solution the eigen-value problem may be solved by various numerical or analytical techniques. numerical methods for nonlinear problems usually depend on iterative procedure. the procedure of the adopted numerical method that is used in this study is outlined, as follows (8) : 1. compute the stiffness matrix [k] from applying the coefficient patterns for finite difference operators fig.(3) at the interior nodes of the plate. 2. compute the geometry matrix [b] from applying the coefficient patterns for finite difference operators fig.(3) at the interior nodes of the plate. 3. compute the inverse matrix for the stiffness matrix [k] (by gauss-jordan or other suitable technique) 4. make [c] matrix by multiplying the inverse matrix [k] -1 by the geometry matrix, as follows: [c]=[k] -1 [b] al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 283 [c]{w}=λ * [i] {w} (c-λ * [i]){w}=0 where λ* = = where the largest eigen-value ( ) of the matrix [k]-1is the reciprocal of the smallest value of the eigen-value(λ) of the matrix [k]. by applying the following steps (a-d) to eq. (10), the minimum eigen-value can be obtained: aassume initial trial vector which may be taken equal to 1.0 bsubstitute the vector at eq.(10) capproximate value of ( ) is obtained by dividing the first element of the column matrix[c] by w1, ( ) = first row of [c] / w1 where w1 is the first element of the matrix dthe second approximate value of the characteristic vector is obtained by: these steps can be continued until the errors become sufficiently small where the used error criteria is the average of the sum of the absolute differences: thus; the natural frequency of isotropic curved thin plate with constant thickness will be: 5. boundary conditions the situation of the boundary condition of the circular plate should be characterized to find the solution. thus the boundary conditions of a circular plate with a radius (r) may be defined as: 1. fixed edge (clamped edge) : al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 284 2. simply supported edge: 6. numerical results the derived numerical schemes for determining the natural frequency (w) were programmed in order to analyze different cases for an isotropic curved plate. results of the numerical analysis for the present investigation was compared with those obtained from the finite element analysis program abaqus. abaqus provides both triangular and quadrilateral shell elements with linear interpolation and userchoice of largerand small-strains formulations. for most of applications large-strain shell elements (s4r, s3r, and sax1) are appropriate with these considerations. in the following study the s4r (4 node shell element) is used in the analysis. the present study was performed for a steel plate with the following properties: inner radius = 1 m and outer radius = 2 m. modulus of elasticity e = 200 gpa. poisons ratio υ = 0.3 . thickness t = 10 mm . several parameters were concerned in this study. these parameters are : 1. mesh size 2. aspect ratio and boundary conditions 3. curvature effect  mesh size in order to investigate the effect of mesh used in the presented finite difference method, a curved plate of angle 38.197 ○ and with the previous properties was analyzed with different mesh sizes and for two types of boundary conditions, simply support and clamped support. the results of convergence as a function of mesh size for both types of boundary conditions were shown in table(1) and table (2). also fig. (3) and (4) show the convergence of the calculated natural frequency with those of abaqus f.e. program, and fig. (5) shows a sample of the deflection values of ssss plate for both finite difference and finite element results. it can be noticed that the natural frequency value obtained from both finite difference and finite element methods goes to a value of approximately 19.81 and 35.84 for both simply and clamped supports, also, the (15×15) mesh gives a difference of about 0.35% and 0.93% of final predicted values of both two types of supports. however, a mesh of 10×10 is very useful to be used in the analysis procedure because its saving time and it has a difference around 1% of predicted values of natural frequencies. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 285  aspect ratio and boundary conditions the effect of both aspect ratio and boundary condition was investigated. the aspect ratio for the curved plate was taken as (a/b) where a represent the length of the plate in radial direction and b represents the average width of the plate which can be obtained by multiplying the average radius by the radian value of the substantial angle. the studied aspect ratios were starts from (0.5 to 3) and for four types of boundary conditions surrounding the plate. these boundary conditions are : 1ssss ( simply supported all around) 2cccc ( all edges are clamped) 3scsc (both bottom and top edges are simple and both left and right edges are clamped) 4cscs (both bottom and top edges are clamped and both left and right edges are simple) table (3) and fig. (6) show the natural frequencies results of the present finite difference procedure with different types of support conditions and aspect ratios. note that s and c symbols represent simple and clamped support. from these results it can be seen that values of the natural frequency of a plate of boundary conditions (scsc) are closed to a plate of clamped supports in lower values of aspect ratios and they are closed to a simply support plate in a higher values of aspect ratios. while , a plate of boundaries (cscs) has an adverse behavior within the used range of aspects ratios.  curvature effect the curvature effect was studied by increasing the average radius of the plate (i.e radius at the center of the plate) from 1 to ∞ so that the aspect ratio was kept to be equal to 1 with a length of 1m. so when r goes to ∞, the plate will be like a rectangular plate of dimensions (1x1)m . also two types of boundary conditions was taken into account in studying the curvature effect, simply and clamped supports. the results of curvature effect on both types of boundary conditions are listed in table (4). while fig. (7) shows these results on a logarithmic x-axis represents the radius value and natural frequencies value represented on the y-axis. from the results shown below it can be seen clearly that when r goes to ∞, the plate will behave as a square plat of dimensions 1x1m which has a natural frequency of 19.739 and 35.841for both simple and clamped supports respectively. in the current finite difference scheme the calculated natural frequency has a difference of round 0.7% from the analytical values of square plate. 5. conclusions the free vibration of thin curved circular isotropic plate was investigated herein. a finite difference approach was presented to analyze the plate. the validity of the adopted approach was compared with finite element approach which was done by using software package (abaqus). the investigation was carried out to simulate the natural frequency of thin curved plate with different types of boundary conditions, aspect ratios, curvature and different mesh size. the following are the main points concluded after studying the results obtained from the present study: 1. the results of the adopted finite difference approach of analysis showed good agreement with those obtained by finite element analysis (abaqus). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 286 2. the schemes of finite difference approach which were derived in the present study can be used to analyze curved circular thin plate with a good agreement results. 3. the present study shows the validity of the derived finite difference schemes with a very small error and for any suitable mesh size if compared with finite element analysis program package results 4. finite difference method is more efficient for such problems than finite elements method (software package), since f.d.m gives good agreement of results with less time of calculations. 5. the finite difference method gives an under estimations value for natural frequency which it is more safe than finite element method which give an over estimation values for such structures . references [1] a.w. leissa: "vibration of plates". nasa sp-160 (1969). [2] stephen p. timoshenko, s. woinowsky-krieger: "theory of plates and shells". mcgraw-hill (1981). [3] a. w. leissa: "the free vibration of rectangular plates". journal of sound and vibration, 31(3), pp. 257--293 (1973). [4] klaus-jurgen bathe: "finite element procedures". prentice-hall, inc. (1996). [5] j. n. reddy: "finite element method". mcgraw-hill, second edition, (1993). [6] gorman,d.j. “an exact analytical approach to the free vibration analysis of rectangular plates with mixed boundary conditions.” j. sound and vibration, vol.93, no.2, 1984, pp.235-247. [7] s. timoshenko and s. woinowsky-krieger "theory of plates and shells", mcgraw-hill, second edition, 1987 [8] harik, i.e., liu, x., balakrishnan, n., “analytical solution to free vibration of rectangular plates.” j. sound and vibration, vol.153, no.1, 1992, pp.51-62. [9] husain m.h., alwash n.a., amash h.k, “free flexural vibration of rectangular thin plate with tapered thickness.” eng. of technology, vol.21, no.10, 2002, pp.736-745. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 287 table (1): finite difference and f.e. results for a simply supported curved plate mesh size ω (f.d) (rad/sec) ω (f.e) (rad/sec) 4x4 18.693 21.087 5x5 19.067 20.655 6x6 19.277 20.416 7x7 19.408 20.271 8x8 19.497 20.178 9x9 19.560 20.113 10x10 19.607 20.066 11x11 19.644 20.031 12x12 19.674 20.003 13x13 19.699 19.981 14x14 19.721 19.964 15x15 19.739 19.950 table (2): finite difference and f.e. results for a clamped supported curved plate mesh size ω (f.d) (rad/sec) ω (f.e) (rad/sec) 4x4 28.949 42.198 5x5 31.019 39.822 6x6 32.341 38.684 7x7 33.230 38.035 8x8 33.853 37.628 9x9 34.306 37.354 10x10 34.644 37.162 11x11 34.903 37.021 12x12 35.106 36.915 13x13 35.268 36.833 14x14 35.399 36.768 15x15 35.507 36.716 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 288 table (3): finite difference natural frequencies in terms of of curved plate with different boundary conditions and aspect ratios support type ssss cccc scsc cscs aspect ratio ω (rad/sec) ω (rad/sec) ω (rad/sec) ω (rad/sec) 0.5 47.45008 88.66515 81.68419 53.33016 0.75 27.08775 48.76832 42.69226 34.12574 1 19.60723 34.64397 27.87902 27.88447 1.25 16.08721 28.66401 20.82557 25.24501 1.5 14.16622 25.79708 17.04361 23.91319 1.75 13.00771 24.27092 14.84224 23.1532 2 12.25685 23.38445 13.47623 22.67953 2.25 11.74301 22.83161 12.58302 22.36439 2.5 11.37613 22.46648 11.97287 22.14402 2.75 11.10513 22.21385 11.54042 21.98377 3 10.89932 22.03229 11.22416 21.86353 table (4): finite difference natural frequencies in terms of of curved plate with different boundary conditions and different radiuses r(m) theta (deg) cccc ssss ω (rad/sec) ω (rad/sec) 1 57.29578 35.06038 19.99886 1.5 38.19719 34.64397 19.73921 2.5 22.91831 34.45288 19.66049 3.5 16.37022 34.40288 19.64656 4.5 12.7324 34.38265 19.6421 5.5 10.41741 34.37249 19.6402 10.5 5.456741 34.35769 19.63795 15.5 3.696502 34.35468 19.6376 20.5 2.794916 34.35359 19.63749 30.5 1.87855 34.35279 19.63742 50.5 1.13457 34.35237 19.63738 100.5 0.570107 34.35219 19.63737 ∞ 0.057267 34.35213 19.63736 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 289 figure (1): geometry of the curved plate and node distribution λ wi + wi = 0 figure (2): finite difference scheme of curved plate differential equation al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 290 figure(3): finite difference versus finite element results for a simply supported curved plate figure(4): finite difference versus finite element results for a clamped supported curved plate al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 291 f.d f.e figure (5): deflection values for first mode of ssss plate for finite difference and finite element figure (6): finite difference natural frequencies of curved plate with different boundary conditions and aspect ratios figure (7): finite difference natural frequencies of curved plate with different boundary conditions and different radiuses article al-qadisiyah journal for engineering sciences 12 (2019) 084–089 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: gofabdh@gmail.com (gufran a.hassan) https://doi.org/10.30772/qjes.v12i2.593 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. design and study the performance of optical nanoantenna gufran a.hassana*and jawad a.hassana adepartment of electronic and communication engineering,university of baghdad institute of laser for postgraduate studies,baghdad -iraq a r t i c l e i n f o article history: received 22 may 2019 received in revised form 30 june 2019 accepted 30 june 2019 keywords: optical nanoantenna s-parameter resonance freq a b s t r a c t recently, the light metallic interaction of nanostructures has grown to be an area of intensive care research due to advances in modern fabrication techniques. unique effects have been observed in a nanostructure, and their applications have been found in various areas like in the manipulation of light on the nanometer scale. in this paper nanoantenna has been introduced and invetigated by studing the effect of changing its parameters such as (shape, length, thickness, and the gap distance between two nanostructures) on the response of the nanoantenna (far field directivity, optical resonance frequency, and s-parameter). here, a bow tie antenna has been chosen and additional parameters have been considered in the simulation, such as antenna thickness and material, and substrate material . the simulations have been generated using computer simulation technology (cst) studio. optical antenna is performed from a pair of nanoparticles brought in close nearness, these pairs are separated by small gap to make a high electric field in its gap region. this feature can be employed for biosensing or sers to improve the detection limit and measure the presence of single molecules. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the field of an optical nanoantenna is a quickly developing area, optical antenna is formulated and major characteristics relevant to this structure are identified. a class of nanoantennas, metallic and dielectric are made and discussed. the study of techniques and optical phenomena in the nanometer (nm) scale are called a nano-optics [1]. nanoantennas are used to convert electromagnetic wave radiation into electric current and vise versa, so nanoantennas are the same of antennas at radio frequencies and microwave ]1[. the radio frequency (rf) antenna is a good technology able to transmit electromagnetic wave that is localized within a great sub-wavelength ]2[. but in the operation of the nanoantennas at a visible wavelength different from (rf) antennas and should be corrected the design and analysis rules to the nanoantennas ]1[. so, the antennas could work in the visible of the electromagnetic spectrum when the dimension of the antenna is decreased to a nanometer range (nm) ]3[, and the frequency is at (hundreds of terahertz) high frequency to operate in visible light. the earlier proposed antennas which are related to the geometric effects on the response of nanoantenna were yu-ming, w., le-wei, l., & bo, l. (2010, april), [4]. when changing the gap length of the bowtie nanoantenna from 10 nm to 40 nm the closer arrangement for an antenna with narrower gaps tends to exhibit higher light intensity. the intensity at resonance for nanoantenna with the separation gap of 10 nm is much higher than those with a gap of 40 nm . murad, fadel a., faris mohammed ali, and ali azzawi hassan. (2016):[5] noticed that the change of the length of optical nanoantenna affects on the electrical fields in a direction of propagation waves (x, y), that shows approximately linear behavior. so, the increased of the face area of the optical nanoantenna to increase the length decreasing the electric field in the gap for two electric fields in y direction (ey) and x direction (ex), which led to distribute charges over a larger area, and therefore led to less concentration of charge points of convergence. there are many applications of nanoantenna such as, medical aaplications (diagnosis, drug delivery, textile engineering), chemical and environmental applications (stimulus), and electronics & communications (semiconductor devices, optical devices). http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i gufran a.hassana and jawad a.hassan /al-qadisiyah journal for engineering sciences 12 (2019) 084–089 85 2. design of the optical nano antenna the optical nanoantenna has been designed with a thickness of 20 nm representing the total thickness of the constituent layers which consist of 2 layers (gold au silicon dioxide sio2). the first proposed antenna consists of flat edge bow-tie structure and the other side is tip with a width w= (140 ) nm, thickness t=(20)nm, a length l= (130)nm gap distance g=(10)nm, 𝛼=( 64.94˚) and the material is (gold a lossy metal) without substrate and in the second section these nanoantenna are printed on a substrate silicon (normal) material set as a default type normal epsilon= 11.9, mu = 1, electric cond= 0.00025 [s/m], rho = 2330 [kg/m^3], thermal conductivity = 148 [w/k/m], thermal expansion = 5.1 [1e-6/k], and with a width w=(200) nm, length l=(290) nm, thickens t = (20) nm as shown in fig. 1. the substrate ahs been used with the nanoantenna because of nano-antennas have the capability to detain light down to the nanoscale. due to their plasmon resonance properties a huge field intensities, a number of instructions of magnitude upper than the incident one, have been achieved within these structures, allowing to study of the light-matter interaction in a nanoscale. one substantial achievement is that the optical resonances can be tuned with dielectric constant and geometrical form of the nanostructures and also with the illumination properties (polarization, wavelength) and so on. the overlap between the intense subwavelength resonant mode and diffraction limited incoming waves is in general weak, alternate solutions were recently proposed to improve light conjugation into the plasmonic nanostructures. these solutions depend on the conjunction between optical dielectric resonators of higher quality factors and nanoantenna [6]. when the current hardly flows through the material. therefore, these materials are a higher conductivity. so, the conductivity is the power loss in the material. lossy metal is defined as material with good conductivity when the material conductivity is more than zero [7]. 𝑗 = 𝜎𝐸 (1) j is the current density e is the electric field 𝜎 conductivity electromagnetic simulator is used to design the antenna and to do numerical analysis. the proposed antenna is capable of concentrating the electric field in the side of metal of the bow-tie by a discrete port with incident frequency f= (0-700) thz. to apply the explanation of boundary value problems in engineering (fem) method a computational technique is used. the boundary problems are known as (a field problem), the changeable field depends on the interest it is controlled by the differential equation [8]. the boundary condition is the specific standards of the field variables on the boundary of the field [8]. so, the optical problems would be solved by maxwell's equations [11], by using the harmonic approaches [9]. 𝐸(𝑡) = 𝐸˳𝑒 −𝑖𝑤𝑡 (2) with no outer charge or current 𝜌 = 𝐽 = 0 it can apply the equation of an electric field [9], ∇ × 𝑀−1 ∇ × 𝐸 − 𝜔2𝜀𝐸 = 0 (3) ∇ ∙ 𝜀𝐸 = 0 (5) this antenna is designed to study the electromagnetic radiation (far field directivity, s -parameter, radiation pattern ) which is analysized with a linear polarized in this simulation. when using numerical settling of maxwell’s equation in the electromagnetic simulation, a good type of mesh affects on the simulation speed and precision. so,( hexahedral) mesh grid is considered where the density of the mesh is determined by the cell size and cells per wavelength are given as 20. the number of largest cell mesh is measured as 71.5657 and the number of cells is 21,120 , excitation of surface plasmon oscillation occurs due to the impinging of visible or infrared light on the antenna surface which creates hot spots where the field intensity become enhanced and drives the current towards the feeding point of the antenna, by using these features, the antenna can be designed for many applications. 3. radiation pattern an antenna radiation pattern is defined as a mathematical function of the radiant personality of an antenna as a meaning of space coordinates are known as (radiation pattern) it is calculated on the area of the far-field and it is pictured as a function of a directional coordinate [10]. as shown in figs. 2 and 3, the bow tie antenna has a (donut) form radiation pattern; in the donut form throw the z-axis, which would identify to the radiation straight overhead the antenna so, a very small power will be transmitted. but throw the x-y plane the transmitted power is maximum [11]. figure 2 3-d radiation pattern for optical bowtie nanoantenna with a length l= (130)nm, width w= (140 )nm, 𝛂=( 64.94˚) ,thickness t=(20)nm, gap distance g=(10)nm, material is (gold a lossy metal) this nanoparticles are with a silicon (normal) substrate with w=(200) nm, l=(290)nm ,t = (20) nm ,frequency=(650)thz figure 3 3-d radiation pattern for optical bowtie nanoantenna with a length l= (130)nm, width w= (140 )nm, 𝜶=( 64.94˚), thickness t=(20)nm, gap distance g=(10)nm, the material is (gold a lossy metal) without substrate frequency=(650)thz 86 gufran a.hassana and jawad a.hassan /al-qadisiyah journal for engineering sciences 12 (2019) 084–089 the far-field directivity of this bowtie nanoantenna was calculated as shown in the figs. 4 and 5. figure 4 far-field directivity for optical bow tie nanoantenna with a length l= (130)nm, width w= (140) nm, 𝜶= (64.94˚), thickness t= (20) nm, gap distance g= (10)nm, material is (gold a lossy metal) this nanoparticls are with a silicon (normal) substrate with w= (200) nm, l= (290) nm, t = (20) nm figure 5 far-field directivity for optical bowtie nanoantenna with a length l= (130) nm, width w= (140) nm, 𝜶= (64.94˚), thickness t= (20) nm, gap distance g= (10) nm, the material is (gold a lossy metal) these nanoparticles are without substrate at a frequency=650thz the red curve stands for e𝜃 𝑝𝑎𝑡𝑡𝑒𝑟𝑛 , the blue lines are marked for a half power bandwidth the green curve is the magnitude of the back loop the main lobe magnitude=5.72 db, main lobe direction=180 deg, and the angular width (3) db=126.8 deg. at frequency=650 thz for bow tie without substrate. but for bow tie with a substrate, it was the main lobe magnitude=3.19 db and the main lobe direction=180 deg. sometimes the antennas have a polar of (omnidirectional) which founds a radiation pattern is (isotropic) in a single plane. so, a bow tie antenna has omnidirectional pattern [11]. it shows a half power bandwidth obtained at a frequency (650 thz) by simulation of the optical bowtie nanoantenna with and without substrate, the radiation pattern was calculated as shown in figs. 4 and 5. 4. thickness effect in this section, the effects of the thickness on the response of nanoantenna were studying. by simulating of optical bowtie nanoantenna with the same parameter above this can be shown in fig. (6)(a,b,c,d,e) when change the thickness of bowtie nanoantenna as t=( 50,40,30,20,10, )nm respectively , with fixed the other parameter of bowtie nanoantenna length l= ( 130)nm, width w= (140 ) nm, 𝛼=( 64.94˚) , gap distance g=(10)nm, material is (gold a lossy metal) without a substrate and frequency at (650)thz. \ from the results, we notice that when changed the thickness of nanoantenna the field enhancement at the tip of the nanoantenna increase when the thickness decreases [12]. and the increasing of electric field enhancement when decreasing the thickness because of the intense coupling near –the field in thickness and this is driving to a great partial plasmon shift [12]. as shown in fig. (6) (a, b, c, d, e) the directivity increase when decreases the thickness of bow tie nanoantenna. when the thickness (50)nm the directivity is (8.58e+0.8) v/m and when the thickness (10) nm the directivity is (9.36e+0.8) v/m (a) t= (50) nm (b) t= (40) nm (c) t= (30) nm (e) t= (20) nm figure (6) (d) t= (10) nm gufran a.hassana and jawad a.hassan /al-qadisiyah journal for engineering sciences 12 (2019) 084–089 87 5. material effect in this section, the effect of choosing the material of nanoantenna was studying the first way was studying the effect of the coefficient of the materials used. the second way was studying the capability of the material to simulate a current as shown in fig 7.(a-d). by dint of the radiant flux incident on the nanoantenna [13]. it was studying the different material used in the design of bowtie nanoantenna with a fixed of other parameters (length, gap distance, thickness). the result was as shown in table 1. table 1 result of optical bowtie nanoantenna with a different material material s-parameter (db) discrete port current (db) resonance frequency (thz) gold -38.6 -17.7 367 nickel -2.68 -28 145.4 silver -31.3 -16.8 369.4 aluminum -37.9 -17 367 table 1. shows the resonance frequency, sparameter, and current response for different material are used in a simulation design of bowtie nanoantenna with width w=(140 ) nm, a length l= ( 130)nm, 𝛼=( 64.94˚) ,thickness t=(20)nm, gap distance g=(10)nm, the material is (gold ,nickel,silver,and aluminum) without a substrate the results were changed depending on the optical properties of the materials used. so, it is very important to choose the properly material in the design to getting good efficiency of bowtie nanoantenna [13]. 6. gap effect antenna theory provides the improvement of the electric field (e-field) in close proximity to a sharp end metal spot. so, antennas have been making a resonant in (ir) and microwave region when it is designed as a nanoscale metallic with a sharpened will progress locally enhanced (e-field)[14]. so, when fabricated two a nanoscale triangles tip to tip metallic with a small distance gap between them this is a bowtie nanoantenna which gives a high electric field intensity in the air of the gab [14,15]. because of a localized surface plasmon excitation [15] so, by varying the gap distance between the two nanostructures we can be controlling the enhancement of electric field around the gap, and the resonance frequency, s-parameter, and wavelength. this can be shown in fig 8 by simulation of a bow tie nanoantenna with a length l= ( 130)nm, width w= (140 )nm, 𝛼=( 64.94˚), thickness t=(20)nm, gap distance changed as g=(30,25,20,15,10,5) material is (gold a lossy metal) this nanoparticles are printed on a silicon (normal) substrate with w=(200) nm, l=(290)nm ,t = (20) nm ,.this result shows a correlation between the gap and resonance frequency when the light is parallel polarized to the axis along the pairs that combine to the nanoparticle center [14]. as shown in table (2), at a shorter gap the resonance frequency is increasing and the spectra sharply a blue-shift. but, at the long gap the resonance frequency is decreasing and the spectra sharply to a redshift and this distance gap effect too on s-parameter (reflection coefficient). as shown in fig 8. table (2) result of optical bowtie nanoantenna with a substrate and with a different distance gap gap (nm) resonance frequency(thz) s-parameter (db) wavelength (nm) 30 310.23 -16.9 966.4 25 320.45 -17.8 935.54 20 330.68 -19.11 906.59 15 343.18 -20.97 873.57 10 356.82 -24.1 840 5 377.3 -33 795 (a) for aluminum (b) for silver (c) for nickel (d) for nickel figure 7 shows the current (db) vs. frequency (thz) for different materials. figure 8 effects of change the gap of the nanoantenna with substrate on the ( resonance frequency ,s-parameter,and wavelength). -200 0 200 400 600 800 1000 1200 0 10 20 30 40( re so n a n c e f re q u e n c y , sp a ra m e te r, a n d w a v e le n g th ) gap(nm) resonance frequancy(thz) sparameter(db) wavelength(nm) 88 gufran a.hassana and jawad a.hassan /al-qadisiyah journal for engineering sciences 12 (2019) 084–089 these steps of simulated were repeated with the same optical bowtie nanoantenna without substrate surely it is the same effect of bowtie nanoantenna with a substrate we have, but the results of bowtie nanoantenna without substrate are the best for the resonance frequency and optical wavelength. as shown in fig. 9. and the result in a table 3. figure 9 effects of change the gap of the nanoantenna without substrate on the( resonance frequency ,s-parameter,and wavelength) table (3) result of optical bowtie nanoantenna without a substrate and with a different distance gap gap (nm) resonance frequency(thz) s-parameter (db) wavelength (nm) 30 317 -22.5 945.57 25 326.14 -23.3 919.21 20 336.36 -24.4 891.28 15 347.7 -26.18 862.2 10 359.1 -29 835.08 5 376.6 -34.7 796.05 7. s-parameter s11 s-parameter is representing the amount of the power that reflected from the antenna it is could write as a gamma (γ) called return loss, [11]. when s-parameter (s11) is = -10db this is mean if 3 db of power is reached to the antenna then -7db will be reflected and the rest of the power was accepted to the antenna, this accepted power is each emit or absorb as a wounded within the antenna. if (s11) is 0db this meaning no power is radiated all power will be reflected from the antenna. fig. 10. (a-f) shows the results of s-parameter of optical bowtie nanoantenna which show in fig. 1. with a substrate when changing the distance gap g= (30,25,20,15,10,5) nm respectively. fig. 11. shows the results of s-parameter of optical bowtie nanoantenna which show in fig. 1. without a substrate) when changing the distance gap g= (30,25,20,15,10,5) nm respectively, from figs. 10. and 11. we notice that s-parameter is a function of the gap , decreasing gap leads to increasing the reflection coefficient of the nanoantenna. -200 0 200 400 600 800 1000 0 10 20 30 40(r e so n a n c e f re q u e n c y , sp a ra m e te r, a n d w a v e le n g th ) gap(nm resonance frequancy(thz) sparameter(db) wavelength(nm) (a) g=(30)nm s-parameter for g=(30)nm (b) g=(25)nm s-parameter for g=(25)nm (c) g=(20)nm s-parameter for g=(20)nm (d) g=(15)nm s-parameter for g=(15)nm (e) g=(10)nm s-parameter for g=(10)nm (f) g=(5)nm s-parameter for g=(5)nm figure 10 the results of s-parameter of optical bowtie nanoantenna gufran a.hassana and jawad a.hassan /al-qadisiyah journal for engineering sciences 12 (2019) 084–089 89 8. conclusion 1optical antennas are the general tool for the handling of light on the scale of a nanometre and they are also able to control a farfield area. present optical antenna research is being aggravated in special by expansion in nanofabrication technology and rf antenna analogies. 2change in the parameter of optical nanoantenna, such as gap distance, effects on the resonance frequency and the sparameter. 3decreasing the distance gap between two nanostructures of a bowtie antenna leads to increase the resonance frequency and sparameter and a highly shift in the wavelength. 4 increasing the distance gap between two nanostructure of a bowtie antenna leads to decreasing the resonance frequency and s-parameter and a high redshift wavelength. 5when decreasing the thickness of the bowtie antenna this leads to increase enhancement of the electric field and increasing the directivity in the tip of the antenna. 6when changing the material of bowtie antenna the results are effected because of the change of the material optical properties effects on the resonance frequency with cause a shift and change the induced current. so by controlling the parameter of a bowtie nanoantenna, we can have the best result as we need, this bow tie nanoantenna can be the best to use in the optical application if used by incident electric field frequency at (0700thz) the wavelength is (600-900)nm, so, study the effect of all these parameters of nanoantenna on the response of the antenna together can help the research to choose the design which needs for any application with a special parameter and spatial resonance frequency or reflection coefficient. references [1] novotny, lukas, and bert hecht. principles of nano-optics. cambridge university press, 2012. [2] alu, andrea, and nader engheta. "theory, modeling and features of optical nanoantennas." ieee transactions on antennas and propagation 61.4 (2013): 1508-1517 [3] scholder, olivier. fabrication, simulation and characterization of tunable plasmonic nano antennas. diss. eth zurich, 2014. [4] yu-ming, w., le-wei, l., & bo, l. (2010, april). geometric effects in designing bow-tie nanoantenna for optical resonance investigation. in 2010 asia-pacific international symposium on electromagnetic compatibility (pp. 1108-1111). ieee. [5] murad, fadel a., faris mohammed ali, and ali azzawi hassan. "study the effect of change the antenna length on the performance of optical nano-antenna using plasmonic surfaces." journal of kerbala university 14.2 (2016): 124-139. [6] el eter, ali, et al. "huge light-enhancement by coupling a bowtie nano-antenna’s plasmonic resonance to a photonic crystal mode." optics express 22.12 (2014): 14464-14472. [7] blythe, a. r. "electrical resistivity measurements of polymer materials." polymer testing 4.2-4 (1984): 195-209. [8] grandin, hartley. fundamentals of the finite element method. new york: macmillan, 1986. [9] manley, phillip, et al. "design principles for plasmonic nanoparticle devices." progress in nonlinear nano-optics. springer, cham, 2015. 223-247. [10] balanis, constantine a. antenna theory: analysis and design. john wiley & sons, 2016. [11] choma, john. "scattering parameters: concept, theory, and applications." univ. southern california, los angeles, ca, usa, tech. rep. ee 541.2 (2006). [12] yang, jie, et al. "optimizing the bowtie nano-antenna for enhanced purcell factor and electric field." progress in electromagnetics research 44 (2014): 93-99. [13] mora-ventura, brhayllan, et al. "responsivity and resonant properties of dipole, bowtie, and spiral seebeck nanoantennas." journal of photonics for energy 6.2 (2016): 024501. [14] fromm, david p., et al. "gap-dependent optical coupling of single “bowtie” nanoantennas resonant in the visible." nano letters 4.5 (2004): 957-961. [15] khaleque, abdul, et al. "integration of bow-tie plasmonic nano-antennas on tapered fibers." optics express 25.8 (2017): 8986-8996. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 383 experimentail and theoretical investigation for behavior of r.c beams with tensile reinforcement lap splicec strengthened by cfrp laminates prof. dr. ammar y. ali1 mr. labeeb s. hussein2 1babylon university, college of engineering, civil department 2al-qadissiyia university, college of engineering, civil department (al_yassri1986@yahoo.com) abstract the main objective of the research reported in this paper was to present an experimental and analytical study for the effect of external strengthening by cfrp laminates on the behavior of beams containing tensile reinforcement lap splices such as ultimate load, ductility and mode of failure. to meet the objective, seventeen nsc beam specimens were tested with cross section of (200x300) mm and overall length 2100mm. each beam was designed with bars spliced in a constant moment region at midspan. the variables used in the investigation were bar size, presence of transverse reinforcement in the splice region and strengthening scheme by cfrp laminates. from the experimental study the results show that the use of cfrp sheet to upgrade the r.c beams containing tensile reinforcement lap splices has significant effect on the behavior of these beams such as ultimate load, cracking load, deflection and mode of failure where the percent increase in ultimate load was about (11-47)% and with elimination the possibility of the brittle failure. analytically, three dimensional finite element were used to analyze these members by nonlinear solution technique. ansys computer program (version 9.0, 2004) was performed throughout this study. eight-node brick element has been used to model concrete, two node link element has been used to model steel reinforcement and four node shell element was used to model cfrp straps. the bond between steel reinforcement and concrete has been modeled by using two-node contact element (contac52). the comparison between the experimental and analytical results referred to reasonable agreement and asserted the validity of the numerical analysis and methodology developed in this study with difference by about 10% for ultimate load and 16% for maximum deflection with good estimation for mode of failure. keywords: lap splices, cfrp sheet, stirrups year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 384 الخالصة ديم دراسة عملية وتحليلية عن تأثير التقوية الخارجية بأستخدام الياف الكاربون ان الهدف األساس من هذا البحث هو تق البولمرية على سلوك األعتاب الخرسانية المسلحة والحاوية على وصالت حديد تسليح الشد المتراكبة مثل قابلية التحمل القصوى ه تم صب سبعة عشر عتب خرساني مسلح بأبعاد مقطع والمطيلية وكذلك نمط الفشل. من أجل القبام بالدراسة المشار اليها اعال ملم, تم وضع وصالت التراكب لجميع النماذج في منطقة العزم الثابت. ان المتغيرات االداخلة 2100) ملم وبفضاء كلي 300*200( بينت النتائج العملية في هذه الدراسة هي قطر حديد التسليح, وجود حديد تسليح القص في منطقة الوصلة و نمط التقوية الخارجية. ان استخدام الياف الكاربون البولمرية لتقوية واعادة تأهيل األعتاب الخرسانية الحاوية على وصالت التراكب لها تأثير أيجابي على )% مع ألغاء نمط الفشل القصيف التي 47-11سلوك هذه األعتاب حيث انها اعطت زيادة في قابلية التحمل القصوى في مايقارب ( هم في مثل هذه األعضاء الخرسانية. تحليلياً تم استخدام طريقة العناصر المحددة ثالثية األبعاد لتحليل هذه األعتاب عتبر النتيجة األت ) حيث تم تمثيل الكونكريت بأستخدام عنصر طابوقي ثماني العقد ansys v 9.0بواسطة برنامج ( بأسلوب التحليل االخطي صر رابط ثنائي العقد و الياف الكاربون البولمرية تم تمثيلها بأستخدام عنصر قشري بأربع عقد اما حديد التسليح بأستخدام عنو والنظرية العملية النتائج بين المقارنةان .بالنسبة للترابط بين حديد التسليح والكونكريت تم تمثيله بأستخدام عنصر سطحي داخلي % بالنسبة للحمل األقصى و 10بنسبة اختالف مايقارب معقولة النتائج تكان حيث واضح بشكل العددي التحليل أكدت صالحية .وبتخمين جيد بالنسبة لنمط الفشل النهائي % بالنسبة للهطول األقصى16 introduction for almost 100 years, construction practices in the building of concrete structures have focused on the use of steel reinforcement to transfer tension and shear forces. lap splicing has become the traditional method of connecting the steel reinforcing bars due to the discontinuity of rebars which are manufactured in standard length 6,9,12 meter. a lap can be defined as a two pieces of rebar overlap to form a continuous line which helps transfer loads properly throughout the structure [alyassri 2011]. in general the continuity of rebars can be provided in three methods of splicing, mechanical splices, welded splices and lap splices which is in two types, non-contact lap splices and contact lap splices where the last one is adopted here. over the years, many structural engineers, architects and specifiers have been noticed that lap splicing has few advantages (no-cost splicing) and many disadvantages (poor under condition of reversed and impacting loading). aci-code states that lap splices are not considered reliable under conditions of cyclic loading into the elastic range. the combination of shear and moment in the splice zone is less severe than moment alone. [ferguson and briceno 1969] and the mode of failure of beam containing tensile reinforcement lap splices is independent of the load history but it is a function of confining reinforcement, concrete cover, dimensions, compression reinforcement and bar size [ali 1990]. the concrete strength has an important effect on the splice strength but there is a limit above which an increase in concrete strength begins to be detrimental to splice strength and this is probably due to shrinkage phenomenon, which generates tensile stresses in the surrounding concrete [tepfers 1973]. many researchers reported that the use of carbon fiber reinforced polymer (cfrp) has very significant in upgrading the weakness structure. the materials frp holds many advantages over other materials in civil engineering. it has very high stiffness to weight ratio and high strength to weight ratio. the material exhibits excellent fatigue properties, non-magnetic properties, corrosion resistance, and is generally resistant to chemicals. examining the strength and stiffness of beams with unidirectional cfrp plates was a primary focus of the past research. [meier et al. (1992)] concluded beast results about using cfrp sheet for strengthening of minimally reinforced concrete beams by applying a unidirectional cfrp sheet to the tensile side where increase the the ultimate load about 100% compared to the control beam (unstrengthened) and the deflection of the strengthened beam was 50% less than the control beam. experimental studies were conducted by [kim 2008] by applying cfrp materials to the lap splice region in square and rectangular columns which exhibited a brittle splice failure as-built. after rehabilitating the columns using cfrp jackets and anchors, the failure mode changed from a brittle splice failure to yield of column reinforcement. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 385 2. experimental work the experimental program included preparation and testing of seventeen beams. tested beams were constructed with overall length (2100mm) and with rectangular cross section of (200x300)mm. two ø16mm or ø12mm deformed bars were provided as longitudinal tension reinforcement. rectangular closed stirrups (ø10mm) were provided. all beams were tested under condition of two point loads at a distance of (600mm) from the support to produce a region of constant moment zone (800mm), where lapped splices of tension rebars are provided. in order to identify the test specimens with different reinforcement ratios and strengthening schemes, the following designation system is used: • (b) for control beams and beams without stirrups in the lap region, (bs) for beams with stirrups in the lap region, (bc) for beams with continuous bars (no lap splices), (r) for repaired beams and (p) for pilot beam. • (12) for 12mm diameter of bars in tension reinforcement and (16) for 16mm diameter of bars in tension reinforcement. • (f) for longitudinal strengthening by cfrp and (u) for lateral confinement by cfrp as u-jacket. the beams (b-12, b-16) were kept without strengthening and were considered as control beams for comparison. to study the effect of external and internal strengthening in increasing capacity and ductility of beams containing lap splices, beams were designated in first segment of its symbol by (s) for internal confinement in the lap region by stirrups as shown in (figure 1). beams were designated in second segment of its symbol by (f) for strengthened externally by two strips of cfrp sheet with (75mm) width at edges of bottom face as shown in (figures 2) while the beams were designated in second segment of its symbol by (u) were wrapped partially (as u-jacket) by two strips of cfrp sheet with (75mm) width at ends of splicing region as shown in (figure 3). the repaired beams were loaded by 60% of ultimate load of original beams, with all techniques of strengthening above by cfrp were adopted to it. to prevent cfrp sheet end debonding or concrete cover separation, cfrp sheets strips were extended under supports [garden and hollaway, 1998]. 2.1 design of teasted beam the tested beams were designed so that flexural failure would occur before shear failure. to avoid shear failure design of shear strength at each section of a member is required. it is achieved by combined contributions of concrete and shear reinforcement. a critical part of the design was ensuring the beams failed due to flexure and not shear. the required length of lap for tension splices, established by the test, may be stated in terms of the development length (ld). two different classifications of lap splices are established corresponding to the minimum length of lap required: a class a splice requires a lap of 1.0ld, and a class b splice requires a lap of 1.3ld. in either case, a minimum length of (300mm) applies. lap splices, in general, must be class b splices, according to [aci code-318m-08], except that class a splices are allowed when the area of reinforcement provided is at least twice larger than that required by analysis over the entire length of the splice and when one-half or less of the total reinforcement is spliced within the required lap length. in this work the length of the lap splices of all specimens were designed so the yielding failure will occur in the tension steel reinforcement before the splice fails in bond (ls=1.3ld). only beams type (bs) are including two vertical reinforcement closed stirrups of (10mm) bar diameter as confinement reinforcement at the lap region. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 386 2.2 materials properties normal weight concrete was used to cast the specimens. the 28-day concrete compressive strength was 25 mpa to mimic an older structural member that would be subjected to strengthening. the longitudinal steel reinforcement deformed bars have a 450 mpa, 580 mpa, 520 mpa yield stresses for bar diameters (16, 12, 10)mm respectively. a cfrp sheet has a tensile strength of 4.5 gpa, an modulus of elasticity of 238 gpa, the elongation at break of 1.8% and the thickness of 0.131 mm [sika, 2005]. 2.3 test setup all tested beams are tested in two-points loading. beam specimens were tested as simply supported beams over 2000mm span in 1500 kn capacity hydraulic machine as shown in (figure 4). each beam specimen was supported and loaded by rollers. forces were distributed through steel bearing plate 200mm in length to cover the entire beam width. to observe crack development, beam specimens were painted white with emulsion paint before testing. at the first the specimens loaded by 5 kn to seat the support and the load system, then reduce to zero. the load increment was 5 kn along the test. dial gages of accuracy 0.01 mm installed at the mid span of the beam and under point of loading to measure the deflection. 3. experimental results the main objective of the current research work is to investigate the behavior of tensile reinforcement lap splices strengthened by cfrp laminates. (table 1) shows a summary for test results. test results were analyzed based on load-deflection response at the point of loading, cracking load, ultimate load and failure modes. in beam (b-12) (control beam with spliced bars of 12 mm diameter and without any strengthening). the first crack occurred about 25 kn at the ends of lap region due to the discontinuity in rebar. as load increased the cracks propagated toward midspan and the ends of the lap region were stodgy by cracks afterwards the splitting bond failure occurred at a load of about 135 kn with a brittle configuration and noisily as shown in (figure 5a). in the beam (b-16) (control beam with spliced bars of 16mm diameter and without any strengthening), the first visible cracks appeared at ends of the lap region when the load reached to level about 30 kn. when the applied load reached 80 kn the cracks appeared in the midspan of the beam. with increasing applied load the cracks became wider and propagated rapidly indirection parallel to the splice region. when the applied load reached to level about 150 kn the splitting bond failure occurred in a brittle mode, very noisily and without any preconceived sign as shown in (figure 5b). the load deflection response of the point load for control beams are illustrated in (figure 6). from comparison between specimens (b-12) and (b-16) it’s shown that the decrease in ultimate load and increase in ductility attribute to the decrease in diameter of bar. it can be noticed from the behavior of these beams there are three regions, elastic-uncracked, elastic-cracked and elasto-plastic, the first region terminate when the cracks occur. in beams (bc-12, bc-16) the tension reinforcement was continuous (no lap splices) the first cracks occurred at mid span of these beams at load of about 40 kn. the final mode of failure was flexural tensile failure (ductile failure) by yielding the rebar at the mid span sectionas shown in (figure 5c). for the beams (bs-12, bs-16) the same as control beams but they include 2ø10 closed stirrups in the lap region to provide internal confinement stress. the first cracks year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 387 occurred at the ends of lap region and the cracks were large in number, more uniformly distribution with respect to the control beams that not include stirrups in the lap region. the final mode of failure was flexural tensile failure (ductile failure) as shown in (figures 5d, 5e) due to the presence of the stirrups in the lap region that increasing the bond stress by allowing the more ribs to contribute to stress transfer between bars that form the splice and surrounding concrete. the loaddeflection flexural stiffness of companion beams without and with transverse reinforcement in the splice region was identical below and above the flexural cracking load. the presence of transverse reinforcement did not affect the flexural cracking load of the beam specimens. in the beams (b-f12, b-f16) a two straps of cfrp sheet with 75 mm width were glued at the edges of the tension face along span of beam. in these beams the final mode of failure was rupture in cfrp followed by splitting bond failure (brittle failure) as shown in (figure 5f) with increase in ultimate load about 43%. in the beams (b-u12, b-u16) two wrap of cfrp sheet with 75mm width as a u-jacket were glued at the ends of the lap splice in these beams to provide external confinement. the external confinement provided by cfrp wraps lead to ductile failure as shown in (figure 5g) by eliminating splitting bond failure with increasing in the ultimate load about (11-20)%. beams (bsf12, bs-f16) strengthened externally by two straps of cfrp sheet of 75 mm width were glued at edges of bottom face along the span of beam and strengthened internally by using 2-ø10mm stirrups. this scheme of strengthening gives good indication about using cfrp in improving the ductility by eliminating brittle failure and developing flexural failure out of lap region i.e. the strength of lap splice large of other sections nearly twice that of the other sections this attribute to good confinement provided by cfrp and stirrups and good continuity provided by longitudinal cfrp for the discontinuity in the ends of lap splices. the beams (bs-u12, bs-u16) were strengthened externally by cfrp sheet of 75mm width glued at the ends of the lap splice as a ujacket to provide external confinement, and internally by 2-ø10mm stirrups to provide internal confinement. this technique of strengthening gives good results about eliminating the brittle mode of failure with increasing in ultimate load about (11-20)%. it is decided to load (rbs-12 and rbs16) approximately to 60% of the ultimate load of original beams (bs-12 and bs-16) respectively, then strength them by cfrp sheet in longitudinal direction and confined by wrapping. the results obtained from test for these beams gives good indication of efficiency of cfrp to rehabilitation the damaged beams by developing ductile failure with increasing in ultimate load about 17%. the load deflection curves for the tested beams are illustrated in (figure 6). 4. analytical study in the analytical study, three dimensional finite element analysis was used to investigate the performance of the r.c. beams with and without tensile reinforcement lap splices strengthened by longitudinal or lateral cfrp laminates. ansys computer program (version 9.0, 2004) was performed throughout this study. eight-node brick element(solid65) has been used to model concrete, two node link element (link8) has been used to model steel reinforcement, four node shell element (shell41) was used to model cfrp straps and eight node brick element (solid45) was used to model loading plates. the bond between steel reinforcement and concrete has been modeled by using two-node contact element (contac52). geometry of these elements was illustrated in (figure 7). the full newton-raphson method was used for the nonlinear solution algorithm. the materials nonlinearity due to cracking, crushing of concrete, and yielding of reinforcement were taken into consideration during the analysis. 4.1 description of specimen in finite element by taking advantage of the symmetry of the beams, one half of the full beam was used for modeling. this approach reduced computational time and computer disk space requirements significantly. the one half of the entire model is shown in (figure 8). year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 388 4.2 mesh refinement an important step in finite element modeling is the selection of the mesh density [maekava et al 1983]. because a one half of the entire beam was used for the model, plane of symmetry was required at the internal face. at a plane of symmetry, the displacement in the direction perpendicular to the plane was held at zero. (figure 9) shows boundary conditions for a typical finite element model. 5. finite element results the goal of the comparison of the fe model and the results of tested beams is to ensure that the elements, material properties, real constant and convergence criteria are adequate to model the response of r.c beams containing tensile reinforcement lap splices with or without strengthening. the results obtained from f.e analysis gave good agreement when compared with the experimental results which include, ultimate load, cracking load, maximum deflection and mode of failure as explained in (table 2). finite element analysis with partial bond gives better agreement (more than perfect bond) when compared with the experimental study as shown in (figure 10). this can be attributed to the slip between reinforcing bar and surrounding concrete were neglected in case of perfect bond. the behavior of the two cases (perfect and partial bond) were approximately similar before cracking load but when the loading stages developed the slip occurred due to the crushing of the concrete in front of the bar ribs. 6. parametric study from the reasonable agreement and accuracy of the finite element model including bond-slip phenomena with experimental results as explained above, effect of some selected parameters on beams containing tensile reinforcement lap splices are decided to study; this include: wrapping shape of cfrp sheet. diameter of reinforcing spliced bar. 6.1 effect of wrapping shape. to explain the effect of wrapping shape of cfrp sheet on the behavior of r.c. beams containing tensile lap splices such as ultimate load, cracking load, ductility and mode of failure; two of wrapping scheme are provided (full wrap and u-wrap). from figure (11) it can be concluded there is no significant difference between beams confined externally by cfrp wraps (full and partial) because of the activity of confinement appear in portion abutting to the spliced bars and the u-wrap has sufficient length of development for bonding between cfrp and concrete therefore the confinement by cfrp sheet as a u-wrap have more practically and more economically. 6.2 effect of bar diameter when the diameter of spliced bars increases the splitting and bursting forces will be increased due to the larger stiffness of spliced bar and then lead to early splitting bond failure at low level of ultimate deflection as shown in (figure 12). therefore the larger bar diameters demand adequate lateral confinement, concrete cover and sufficient anchored length to resist aggravated bursting forces and then prevent brittle failure. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 389 7.conclusions 1the longitudinal strengthening by cfrp leads to increasing ultimate load by about (43-47)% but the mode of failure is still brittle whilst the external confinement by cfrp led to increasing ultimate load by about (11-20)% and the mode of failure was ductile. 2using longitudinal cfrp combined with external confinement of wrapping cfrp or internal confinement of stirrups gives the better behavior represented by increasing ultimate load by about (44-47)% and enhancing ductility in comparison with the case of using the longitudinal strengthening alone. 3it can be observed from beams confined internally by stirrups combined with external wrapping of cfrp, there is no significant difference with the case of external confinement alone about (2)% in ultimate load. but this effect may be expected to appear clearly for splicing bars of larger diameter than 20mm. 4in beams with no internal (stirrups) or external (cfrp) confinement in the tensile reinforcement lap splice region, the final mode of failure was a face-side splitting bond failure which was sudden, very brittle, and noisy with ultimate load less than that of a continuous bar by about 13%. 5beams with only external confinement of wrapping cfrp give well result of overall behavior through enhancing the mode of failure by eliminating the brittle failure as well as loaddeflection response and cracking pattern, so this technique can be utilized as alternative technique for internal confinement by reinforcing stirrups. 6the use of external longitudinal cfrp laminates with confinement wrapping of cfrp sheet, may be considered the best way for retrofitting the deteriorated or damaged beams containing tensile lap splices, with increasing ultimate load by about 17% and ultimate deflection 21% and mode of failure was still ductile. 7the present finite element formulation with modeling of materials, cracking, crushing taking into consideration contact (interface element) between steel and concrete for tensile reinforcement lap splices, seems efficient and gives good accuracy through comparison with the experimental results where the maximum difference in the ultimate load was less than 10% and the maximum difference in the maximum deflection was less than 16%, as well as obtaining reasonable estimation for mode of failure (brittle or ductile). 8the use of cfrp strips as lateral confinement in partial u-wrapping gives the same overall behavior as that obtained for full wrapping, where the first is more practical and economical in field of construction engineering. 9neglecting bond-slip phenomena in f.e. analysis of r.c. beams with tensile reinforcement lap splices leads to overestimation in; post-cracking, load-deflection response, ultimate load by about 47% and eliminating the possibility of splitting bond failure. 10increasing diameter of the spliced bars has unfavorable effect on the ductility and the mode of failure. references 1. alyassri, l. s., "analysis for behavior of reinforcement lap splices strengthened by cfrp laimenates", m.sc. thesis, university of babylon, iraq, 2011. year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 390 2. american concrete institute, "building code requirements for structural concrete", 2008, farmington hills, aci-318m-08. 3. ferguson, p.m. and briceno, a. “tensile lap splices, part1: retanining wall type, varying moment zone”, research report no.113-2, center for highway research, the university of texas at austin, july, 1969. 4. ali, a.y., “behavior of lap splices in reinforced concrete beams under inelastic cyclic loads”, m.sc. thesis, university of technology, iraq, december 1990. 5. tepfers, r., “a theory of bond – applied to over lapped tensile reinforcement spliced for deformed bars”, application no.73:2, division of concrete structures, chalmers university of technology, goteborg, sweden, 1973, pp.328. 6. kim, i.s., “use of cfrp to provide continuity in existing reinforced concrete members subjected to extreme loads”, ph.d. thesis, university of texas, austin, august 2008. 7. garden, h., and hollaway, l., “an experimental study of the influence of plate end anchorage of carbon fiber composite plates used to strengthen reinforced concrete beams”, composite structures, vol. 42, 1998, pp: 175-188. 8. maekava, k., and okamura, h., "the deformation behavior and constitutive equation of concrete using the elasto-plastic and fracture model", j. of faculty of engineering, university of tokyo (b), vol. xxxvii, no. 2, 1983. 9. meier, u., deuring, m. and schwegler, “strengthening of structures with cfrp laminates: research and applications in switzer land”, advance composite materials in bridges and structures, k.w. neale and labossiere, canadian society for civil engineering, montreal, 1992, pp.243-251. abbreviations nsc: normal strength concrete cfrp: carbon fiber reinforced polymer year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 391 table (1): summary for test results beam symbol cracking load (kn) pcr/pcrr failure load (kn) pf/pfr under point load deflection (mm) ∆u/∆ur mode of failure pilot 25 130 9.51 splitting bond failure ®b-12 25 135 9.47 splitting bond failure bc-12 40 1.6 140 1.04 12 1.27 flexural tensile failure bs-12 25 1.0 150 1.11 11.3 1.19 flexural tensile failure b-f12 45 1.8 195 1.44 13.1 1.38 rupture of cfrp followed by bond splitting failure b-s12 35 1.4 150 1.11 12 1.27 flexural tensile failure bs-f12 50 2 195 1.44 13.3 1.4 rupture of cfrp followed by flexural tensile failure bs-s12 40 1.6 150 1.11 12.2 1.29 flexural tensile failure ®b-16 30 150 7.5 splitting bond failure bc-16 40 1.33 170 1.13 10.4 1.39 flexural tensile failure bs-16 35 1.17 170 1.13 9.5 1.27 flexural tensile failure b-f16 60 2.0 215 1.43 10.6 1.41 rupture of cfrp followed by bond splitting failure b-s16 50 1.67 180 1.2 10.8 1.44 flexural tensile failure bs-f16 70 2.33 220 1.47 14.1 1.88 rupture of cfrp followed by flexural tensile failure bs-s16 40 1.33 180 1.2 11 1.47 flexural tensile failure ® reference beam pcr = cracking load, pcrr = cracking load of reference beam pf = failure load, pfr = failure load of reference beam ∆u = under point load deflection, ∆ur = under point load deflection of reference beam table (2): finite element results beam symbol cracking load (kn) ultimate load (kn) max. deflection (mm) mode of failure exp theo. exp. theo. exp . theo. exp. theo. exp . theo. exp. theo. ®b-12 25 30 0.83 135 140 0.96 11.0 13.0 0.85 splitting bond failure bc-12 40 45 0.89 140 140 1.0 12.4 13.1 0.95 flexural tensile failure bs-12 25 30 0.83 150 145 1.03 14 13.1 1.07 flexural tensile failure b-f12 45 40 1.13 195 185 1.05 16.3 15.1 1.08 experimentally: rupture of cfrp followed by splitting bond failure analytically: flexural tensile failure year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 392 2 2 125 fig.(1): reinforcement details of specimens (bs) table (3): continued beam symbol cracking load (kn) ultimate load (kn) max. deflection (mm) mode of failure exp theo. exp. theo. exp . theo. exp. theo. exp . theo. exp. theo. b-u12 35 40 0.88 150 150 1.0 13.8 13 1.06 flexural tensile failure bs-f12 50 40 1.25 195 195 1.0 16.4 17.8 0.92 experimentally: rupture of cfrp followed by flexural tensile failure analytically: flexural tensile failure bsu12 40 35 1.14 150 145 1.03 12.8 14 0.91 flexural tensile failure ®b-16 30 30 1.0 150 160 0.94 9.3 10.9 0.85 splitting bond failure bc-16 40 50 0.80 170 180 0.94 11.8 13.7 0.86 flexural tensile failure bs-16 35 30 1.17 170 170 1.0 12.4 13.9 0.89 flexural tensile failure b-f16 60 55 1.10 215 220 0.98 13.7 15.9 0.86 experimentally: rupture of cfrp followed by splitting bond failure analytically: flexural tensile failure b-u16 50 40 1.25 180 180 1.0 12.3 13.5 0.91 flexural tensile failure bs-f16 70 55 1.27 220 220 1.0 15.2 17.0 0.89 experimentally: rupture of cfrp followed by flexural tensile failure ® reference beam 2100 2000 200 200 300 300 650 800 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 393 fig.(2): details of type (f) strengthening fig.(4): control beam in testing machine 75 200 300 75 2100 2100 75 75 200 200 2100 300 75 fig.(3): details of type (u) strengthening year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 394 (a) b-16 (b) b-12 (c) bc-16 (d) bs-12 (e) bs-16 (f) b-f12 (g) b-f16 fig.(5): modes of failure year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 395 fig. (6): load deflection curves for tested beams 7(a) solid65 7(b) solid 45 7(c) link8 7(d) shell41 fig.(7): geometry of elements year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 396 300 mm b-12 b-16 y z x fig.(8): sketch for one half of the beam (not to scale) fig.(9): finite element modeling fig.(10): experimental and theoretical load deflection curves for tested beams 2100 mm 200 mm uz = 0 year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 397 bc-12 bc-16 bs-12 bs-16 b-u12 b-u16 fig. (11): continued year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 398 b-f12 b-f16 bs-u12 bs-u16 bs-f12 bs-f16 fig. (12): continued year 2013 no. 4 vol. 6 qadisiya journal for engineering sciences -al 399 fig. (13): load deflection curves of beams with full and partial wrap fig. (14): load deflection curves of beams with different diameters of bar template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 486 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. structure-properties relationships in heat treated low carbon steel heider yasser thamir alyasiri, materials engineering dept., college of engineering, university of al-qadisiyah, al-diwaniyah, iraq. e-mail: heider.thamir@qu.edu.iq received on 6 september 2017 accepted on 31 october 2017 published on 15 january 2018 doi: 10.30772/qjes.v10i4.496 abstract: the samples of aisi 1018 low carbon steel were heated to austenite zone then cooled in different mediums with different cooling rates. mechanical tests show increase in hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio as cooling rate is increase. ductility has inverse proportionality to cooling rate. the resulting microstructures show decreasing in grains sizes accompanying to cooling rate increase. the relations between mechanical properties and grains size are opposites of relations between mechanical properties with cooling rates. hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio increase as grains size decreases, while ductility decreases. keywords: aisi 1018 steel, heat treatment, grain size, hall-petch, cooling rate. introduction it is obviously clear that iron alloys are the most used through all known metallic and nonmetallic engineering materials. their widespread use is accounted for by many reasons including overall cost and availability, but the main reason still the versatility, where thier properties –mainly mechanical ones– can be changed through a wide range [1]. this versatility is attributed to chemical compositions modification and/or subsequent heat-treatments and in some times mechanical treatments, which can change the presence, number, shape, size, and distribution of phases through steel structure. any alteration of microstructure will strongly affect steels properties [2-4]. it’s possible to modify microstructure without changing composition through application of heat treatment techniques which may introduce new structures. but, in some cases it’s undesirable to change phase and/or composition, or as the case in all pure metals and some of alloys like mild steel where it is unpractical or difficult to alter the presence of phases [5-7]. here, the useful way to alter the properties using heat treatment is through changing the shape, size and distribution of present phase(s). among them (shape, size and distribution), controlling grain size is the most efficient, which can greatly affect properties of the part through refining or coarsening of grains. in general, grain size has inverse proportionality with strength and hardness; otherwise, it has direct proportionality with ductility [8,9,10]. this proportionality was described generally by hall-petch relationship [11]. controlling grains size can be reached by controlling cooling rate of specified part in heat treatment using different mediums for cooling [8,9,12]. many efforts were dedicated to describe the relation between grain size and the intended property for ferrous and nonferrous alloys [10,13,14]. mailto:heider.thamir@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 487 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1. experimental procedures aisi 1018 low carbon steel specimens with mechanical properties shown in table 1 were prepared to heat treatment processes. after, they were divided into groups and heated in electrical resistance furnace to a temperature of 910° c, and held at this temperature for about two hours to ensure heat homogeneity and totally phase change. then, they were cooled in different cooling mediums including ice cooled water (0.5° c), tap water (32° c), machine oil (32° c), still air (32° c), and in the heating furnace (turned off and closed). the approximate cooling rates were: icy water 120° c/sec, tap water 80° c/sec, machine oil 30° c/sec, still air 1.25° c/sec, and closed furnace 0.125° c/sec. the specimens then were ready to be conducted in tensile test, hardness test, and microstructure examination to evaluate properties evolution in accordance with structural changes and attendant cooling rates. table 1: properties of as received aisi 1018 steel. 2. results and discussion 2.1. hardness tests vickers hardness results of icy water quenched, water quenched, oil quenched, air cooled, furnace cooled, and as received specimens are ordered descendingly in table 2. hardness tests were conducted in three regions for each specimen; centre, edge, and middle between them to evaluate hardness change with depth from surface. it can be easily shown that hardness value is greater for a faster cooling medium and vice versa, and hardness for as received specimen is bigger than that for still air and closed furnace mediums, but smaller than other mediums. for each individual specimen the hardness values increase as moving from centre toward the outer surface consistently with increasing cooling rates for regions inside the sample, where the rate of cooling is higher at surface and being lower as the region is approaching the centre of specimen. the difference between hardness of outer surface and inner regions is not at same consistent pattern, difference is bigger for icy cooled medium and nearly equal (no difference) for closed furnace. the reason is that for coldest quenching medium the cooling rates at surface is much higher than inner regions, but, for less cooling mediums the difference will be smaller, and even equal or near equal for very slow cooling medium as the case with closed furnace. figure 1 represents relation between cooling medium and specimen hardness. table 2: hardness of specimens with cooling mediums for different regions in each specimen. e: edge, m: middle, c: centre. cooling medium icy water tap water oil as received (not treated) still air closed furnace hardness hv e m c e m c e m c e m c e m c e m c 292 265 259 242 225 220 228 215 209 186 176 170 154 148 144 120 117 117 2.2. tensile tests results of tensile tests for the specimens are represented in table 3. yield strength, tensile strength, and young modulus also strongly depend on cooling rates, in the same way hardness results do. again, it can be shown that values of yield strength, tensile strength, and modulus of elasticity are higher for a faster cooling medium and vice versa, the values of these properties for as received specimen are bigger than that for still air and closed furnace mediums, but smaller than other mediums (figure 2) . for stiffness which is yield strength mpa tensile strength mpa modulus of elasticity gpa hardness hv kg/mm 2 ductility % average grain size um 473 616 237 170 18 7.2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 488 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. identified by modulus of elasticity (figure 3), it is evident that it follows the same approach as hardness and strength did, depending on cooling rate and accordingly cooling medium. as cooling is faster as stiffness value is bigger. figure 1: relation between cooling medium and specimen hardness at edge (e), middle (m), and centre (c), in different cooling mediums. table 3: yield strength, tensile strength, young modulus, yield/tensile strength ratio, and ductility of specimens with different cooling mediums. cooling medium → icy water tap water oil as received (not treated) still air closed furnace property ↓ yield strength mpa 806 553 513 473 316 271 tensile strength mpa 830 674 637 616 438 397 young modulus gpa 403 277 257 237 158 136 yield/tensile 0.971 0.82 0.805 0.768 0.721 0.683 ductility % 7.7 13.6 14 18.3 25 42 in opposite direction ductility goes with inverse proportionality to cooling rate and attendant cooling medium (figure 4). the ductility of as received (not treated) specimen is smaller than that for closed furnace and still air mediums, but is bigger than other mediums. the maximum ductility is for furnace cooled sample, and minimum one is for icy water quenched sample. when notice values of yield/strength ratio (figure 5), we can recognize that the behavior is the same of hardness, yield, and tensile strength. this factor (y/t) is so important for deformation manufacturing processes employing cold working techniques. when value of yield strength is near to that of tensile strength, it means there is little range of plastic deformation. herein, using this concept we can deduce what sample is more capable to be used in cold working and what one is less useful or even useless. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 489 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2.3. microstructure examination the microstructure is examined and analyzed to determine grains size of phases. typically, in low carbon steel the existing phases are ferrite as a major and pearlite as a minor. using photos obtained from optical microscopy and applying line intercepts method, the grain size is determined for every specimen. grains sizes are given in table 4. the microstructure photos of icy water quenched, water quenched, oil figure 2: cooling medium – yield and tensile strength relationship. figure 3: cooling medium – young modulus relationship. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 490 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: cooling medium – ductility relationship. figure 5: cooling medium – y/t ratio relationship. table 4: grains sizes of specimens according to cooling mediums. cooling medium icy water tap water oil as received (not treated) still air closed furnace grains sizes (micrometers) 4.3 5.4 6.5 7.2 10.7 17 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 491 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. quenched, non-treated, air cooled, and closed furnace cooled specimens are given respectively in a, b, c, d, e, and f in figure 6. the real width of each photo is 227 micrometers. pearlite and ferrite fractions are not the same in all specimens even though they were cut from the same bar, since we can see that as cooling rate increases the pearlite content increases in expense of ferrite (even little), this is because that the non equilibrium conditions encourage pearlite nucleation. the size of grains already inversely proportionates to cooling rate and its corresponding cooling medium, as demonstrated in figure 7. figure 6: icy water quenched(a), water quenched(b), oil quenched(c), non-treated(d), air cooled(e), and closed furnace cooled(f). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 492 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7: cooling medium – grains size relationship. the mean of hardness (figure 8), yield strength, and tensile strength (figure 9) proportionate inversely to grains size, and also the modulus of elasticity does (figure 10). to explain this we need to remember that the main mechanism for strengthening metals and alloys is by hindering dislocations movement, and grain boundaries are one of obstacles that impede this motion. on the other hand it is well known that the total area of grains boundaries increases as grains sizes decrease, and as a consequent the movement of dislocations will be inhibited (partially), leading to apparent improvements on strength and hardness of the alloy, also the increasing of pearlite fraction with increasing cooling rate leads to increase in strength and hardness (pearlite is stronger than ferrite). also decreasing grains sizes lead to decreasing ductility (figure 11). it also can be explained. simply, fine grained crystal has more hinderence to dislocations in the form of grain boundaries, and the available volume for dislocations movements is greatly reduced leading to ductility reduction, with regard to that increasing pearlite fraction also helps in decreasing ductility (pearlite is less ductile than ferrite). at opposite direction, as the size of grain is bigger as the slip figure 8: grains size – mean hardness relationship. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 493 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 9: grains size – yield strength, tensile strength relationship. figure 10: grains size – young modulus relationship. planes are continued through long distances permitting the dislocations to move and metal to deform more with less disrupting (less dislocations pileup at grain boundaries) leading to more ductility, also with regard to increasing ferrite fraction that helps in increasing ductility. according to increase strength and decrease ductility with decreasing grain size, it’s reasonable that (yield strength / tensile strength) ratio will increase as grain size decreases (figure 12). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 494 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 11: grains size – ductility relationship. figure 12: grains size – y/t ratio relationship. conclusions 1. hardness of treated part increases or decreases as the cooling medium has more or less cooling rate (compared with other mediums). 2. in one specimen the hardness of the outer surface is higher than inner regions. and as the cooling being faster as the difference being bigger. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 495 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3. yield strength, tensile strength, and stiffness proportionate directly with cooling rates. but ductility has invers proportionality to cooling rates. 4. yield strength / tensile strength ratio increases as the cooling rate increases, indicating decreasing in cold working ability. 5. as cooling rate increases as the resulting structure has finer grain size, and vice versa. 6. hardness, yield strength, tensile strength, and stiffness increase with decreasing grains sizes. 7. increasing grains sizes will decrease ductility. references 1. william d. callister, david g. rethwisch, “fundamentals of materials science and engineering”, john wiley& sons inc., 2012. 2. peet, m.j., babu, s.s., miller, m.k. et al., “tempering of low-temperature bainite”, metallurgical and materials transactions a, april 2017, volume 48, issue 7, pp. 3410–3418. 3. hallberg, h., adamski, f., baïz, s. et al., “microstructure and property modifications of cold rolled if steel by local laser annealing”, metallurgical and materials transactions a, july 2017. https://doi.org/10.1007/s11661-017-4210-y. 4. s. s. sharma, k. jagannath, c.bhat et al., “effect of heat treatment on mechanical properties of aisi 4147 spring steel”, 3rd international conference on mechanical, automotive and materials engineering (icmame'2013) april 29-30, 2013 singapore. 5. j. adamczyk , a. grajcar, “heat treatment and mechanical properties of low-carbon steel with dualphase microstructure”, journal of achievements in materials and manufacturing engineering, volume 22 issue 1 may 2007. 6. o.h. ibrahim, “comparison of impact properties for carbon and low alloy steels”, j. mater. sci. technol., 2011, 27(10), 931-936. 7. cullen m. moleejane, kazeem o. sanusi, olukayode l. ayodele et al., “microstructural features and mechanical behaviour of unalloyed medium carbon steel (en8 steel) after subsequent heat treatment”, proceedings of the world congress on engineering and computer science 2014 vol ii wcecs 2014, 22-24 october, 2014, san francisco, usa. 8. adnan çalik, “effect of cooling rate on hardness and microstructure of aisi 1020, aisi 1040 and aisi 1060 steels”, international journal of physical sciences vol. 4 (9), pp. 514-518, september, 2009. 9. md israr equbal, parwez alam, rajkumar ohdar et al., “effect of cooling rate on the microstructure and mechanical properties of medium carbon steel”, international journal of metallurgical engineering 2016, 5(2): 21-24. 10. b.q. shi, r.s. chen, w. ke, “influence of grain size on the tensile ductility and deformation modes of rolled mge1.02 wt.% zn alloy”, journal of magnesium and alloys, 1 (2013) 210-216. 11. hall, e.o., "the deformation and ageing of mild steel: iii discussion of results". proceedings of the physical society, section b, volume 64, number 9, 1951. 12. a.i. zakya, a. el-morsyb, t. el-bitar, “effect of different cooling rates on thermomechanically processed high-strength rebar steel”, journal of materials processing technology, 2 0 9 ( 2 0 0 9 ) 1565–1569. 13. k.t. kashyap, t. chandrashekar, "effects and mechanisms of grain refinement in aluminum alloys", bulletin of materials science, vol 24, august 2001. 14. fan, z.; wang, y.; zhang, y. et al., "grain refining mechanism in the al/al–ti–b system", acta materialia, 84: 292–304, 2015. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 punching shear strength and deformation capacity of r.c. slabs with different patch load areas lect. aamer najim abbas dr. husain khalaf jarallah lecturer lecturer amir_najim@yahoo.com khalfdce@hotmail.com department of civil engineering college of engineering al-mustansiriya university baghdad-iraq abstract the main objective of this paper was to evaluate the effect of using different supporting areas or patch loads on a reinforced concrete slab within the slab-column connections. the increasing of the punching shear strength and deformation capacity when subjected to patch load was studied here. an experimental study was carried out on reinforced concrete slabs under a central patch load with circular, square and rectangular shapes of patch areas. a single concrete mix design was used throughout the test program. all of slab specimens were reinforced with distributed mesh reinforcement with equal steel ratios in both directions. the validation of the experimental work was made by analyzing the tested slabs by finite element method under cracking load. the results obtained by the finite element method were found to compare well with those obtained experimentally. in order to calculate the ductility for the tested slabs, the punching load has been determined by applying the published failure criterion and a load-rotation relationship obtained from semi-empirical relationship for the tested slabs. conclusions on the influence of patch area on the punching shear capacity of reinforced concrete slabs were drawn. the experimental results confirm that the strength and deformation capacity are slightly influenced by the shape of the patch area. among all specimens, the slabs with circular shape of patch area exhibited the best performance in terms of ductility and splitting failure. keywords: concrete slabs; punching shear; patch load, ductility, finite element method. حمل البقعة تاثيرالهطول للبالطات الخرسانية المسلحة تحت الثاقب وقابلية القص مقاومة وبمساحات تسليط مختلفة م.د.حسين خلف جارهللا م.عامر نجم عباس الجامعة المستنصرية /كلية الهندسة/قسم الهندسة المدنية :الخالصة مقدار ولمعرفة االعمدة في البالطات الخرسانية المسلحة علىتاثير شكل منطقة االسناد قييمتمن هذا البحث هو الهدف الرئيسي دراسة وقد أجريت في منطقة اتصال البالطة الخرسانية مع العمود عند تسليط االحمال.في قوة القص ومقاومة التشوه الزيادة al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 حديد نسب وقد تم استخدام التسليط. منطقة من شكل مختلف مع بقعية حمالا تحت تحميل خرسانية مسلحة بالطات على تجريبية ملك نفس المواصفات لجميع النماذج مع سمك متساوي. دقة النتائج المستحصلة من الدراسة ترسانة متساوية بكال االتجاهين مع خ حدث ت التيال احماالالعملية جاءت معقولة ومقبولة مقارنة بالنتائج التحليلة المستحصلة من التحليل باستخدام العناصرالمحددة تحت باستخدام معادلة تم عند تسليطهالحمل الذي يتم حساب اليونة تم تحديد .في منطقة الشد في خرسانة النماذج اول تشقق اعنده الشكل كان .ان شكل منطقة تاثير االحمال يؤثر قليال في مقاومة القصتؤكد النتائج العملية .دراسات اخرىالحصول عليها من وفشل الخرسانة. اليونة من حيث أفضل أداء التسليط اعطى منطقةل الدائري 1. introduction in flat-plate floors, slab-column connections are subjected to high shear stresses produced by the transfer of the internal forces between the columns and the slabs (aci-421.1r-08, 2008; aci421.1-99, 1999). normally it is desired to increase the slab thickness or using drop panels or column capitals of exceptionally high strength for shear in reinforced concrete slab around the supporting column. occasionally, methods to increase punching shear resistance without modifying the slab thickness are often preferred (cheng and montesinos, 2010). the ways to transfer the force from column to the slab need to be studied to increase the shear resistance. several reinforcement alternatives for increasing punching shear resistance of slab-column connections, including bent-up bars (hawkins et al., 1974; islam and park, 1976), closed stirrups (islam and park, 1976), shearheads (corley and hawkins, 1968), and shear studs (dilger and ghali, 1981), have been evaluated in the past five decades. but there is a little experimental and theoretical information about the influence of patch area or cross section area shape for supporting column in the reinforced concrete shear resistance. the main purpose of this paper is to introduce an experimental study about punching shear strength and deflection behavior of the reinforced concrete slab with different patch load areas. validity of experimental cracking deflection results was checked by analyzing the tested slabs under cracking load using the finite element method. accuracy of results of cracking deflections is found to be reasonable and acceptable. the load –rotation curve was obtained for the tested slabs by using published semi-empirical relationship (muttoni, 2003). 2. experimental procedure the experimental result is discussed in this paper. 2.1 materials a total of three reinforced concrete slab specimens with loading areas of different shapes have been used in this study. a single concrete mix was used throughout the test program. the concrete which is used in the specimens consists of ordinary portland cement, natural sand and crushed stone aggregate with maximum size of 10 mm. the water/cement ratio for concrete was 0.25. the mix proportions for cement, aggregate and water are given in table (1). deformed steel bars of diameter 5 mm were used in the slab panels. the bars are tested to determine the yield stress, ultimate stress and elongation. the test was carried out according to (astm a615 / a615m, 2003). the steel deformed bars having average yield strength and ultimate strength of 435mpa and 601mpa respectively. 2.2 specimen details details of the slab specimens are given in table (2). details of slabs with reinforcement placements and patch load areas shown in the fig. 1. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 2.3 compressive strength the code of practice assumes the punching shear resistance is proportional to the nth root of concrete strength (aci 318m-08, 2008; bs 8110-part 1, 1997; nzs 3101-part 1&2, 1982). in present work, standard cubes (150 mm) were used according to (bs 1881: part 116, 1983) and they are de-molded one day after casting. testing is carried out at (28) days age. the machine which is used in the tests is a hydraulic type of (3000) kn capacity. the average compressive strength of three cube samples was 41 mpa at 28 days. 3. testing procedure 3.1 test setup the slabs are tested under one point load at mid-span as shown in fig. (2).the four sides of slabs were supported on bearing rollers on identical spreader plates. four steel blocks were used at each corner of the slab as resting supports. these blocks to keep the clear span of 400 mm of all specimens. during testing, corner angles of each sample were properly anchored by means of heavy joist, which was connected to structural floor as shown in fig. (3). there was one dial gage at the mid-span to measure the central slab deflection as shown in fig. (4). 3.2 test procedure before testing, slabs were checked dimensionally, and detailed visual inspection made with all information carefully recorded. after setting and reading dial gage, loading was applied to specimen at an approximately constant rate, up to the peak load, at the same time deflections were measured. deflection was measured at the center of tested slabs by means of (0.01 mm) dial gage, and readings from this gage were recorded for each load increment. failure occurred abruptly in all specimens and loading was stopped after failure. 4. finite element modeling the theoretical analysis was performed by the finite element package program (safe, 2010) under cracking load only. in this analysis, the shell elements are used. the stresses developed in this element are shown in fig. (5).the effect of membrane stresses were included in the finite element analysis of the slabs due to large deflection before punching shear failure. the edges of the slab were vertically restrained along four sides in the finite element model, as in the experimental setup. further, in the finite element model, the loading was applied within the patch load area of central portion of slab model at the top surface to simulate actual experimental loading. for the finite element analysis, the effective flexural rigidity ei taken equal to 0.5ecig, in which ec = young’s modulus of concrete, and ig is the second moment of inertia of the gross section. the multiplier 0.5 is in accordance with the multiplier for beam stiffness in (aci 318m-08, 2008). the finite element meshed model of a typical slab is shown in fig. (6). the comparisons between the experimental and theoretical results of central deflection at cracking stage are shown in table (3). the results obtained by the finite element method are found to compare well with those obtained experimentally. 5. discussion on test results 5.1 observed damage at the end of each test, all models were flipped over in order to mark cracks on the bottom (tension) side of the slab. fig. (7) shows the crack patterns at the failure stage for all three al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 specimens. all the models underwent punching type of failure. it has also been observed that the splitting failure with punching shear failure is more likely in slab with rectangular and square column because of the crack pattern for the main flexural cracks developed directly above the longitudinal reinforcement of all slabs with rectangular and square columns and that led to bond splitting before the punching shear failure. the initial cracking of all the tested slabs was first observed in the tension zone of the slab near the column stub. in case of square and rectangular columns the initial crack was observed under the corner of column. the initial cracks appear in slabs with square and rectangular column faster than in case of circular column because high stress concentration in corners of columns. at this stage of loading the tensile stress in concrete reached the modulus of rupture value and cracking started in the zone of maximum tensile stress. the cracking load, failure load and failure mechanism for all tested specimens are presented in table (4) below. the slab with rectangular columns gives minimum values for the cracking load because of the splitting failure. 5.2 load versus deflection relationship the punching shear loaddisplacement curves for all slabs are shown in fig. (8), and the failure punching shear loads are listed in table (4). according to these results, when the cracks start developing, deflections in the slabs increase at a faster rate, and continues to increase without an appreciable increment in load. finally the deflection increases without any additional load and the dial gage starts to move very rapidly. the maximum deflection of slab with circular column is less than the slab with rectangular and square column. the load-deflection curves showed a slight difference in the deformation behavior under loading for all slabs. when a reinforced concrete slab is subjected to a gradual increase in load, the deflection increases linearly with the load in an elastic manner. after the cracks start developing, deflection in the slab increases at a faster rate. after cracks have developed in the slab, the load-deflection curve is approximately linear up to the yielding of flexural reinforcement after which the deflection continues to increase without an appreciable increment in load. 6. moment curvature curve moment-curvature analyses were carried out using the usual assumption that strains vary linearly across the depth of the section. longitudinal reinforcement was modeled based on the measured material properties including strain-hardening. unconfined concrete (the cover) was modeled based on stress-strain relations obtained from cubic tests. moment-curvature calculations were carried out using the software section designer for (etabs, 2010).in the moment curvature curve, the measured yield strength of the reinforcing steel and the cylinder compressive strength of the concrete were used. the moment curvature relationships for tested slabs thicknesses is given in fig. (9). 7. yield-line analysis the flexural strength for moment curvature curve derived at ultimate strain for concrete moment has been used to derive the peak load in the yield line analysis. the expected flexural failure mechanism for simply supported slab with a point load at the center is illustrated in fig. (10).the relationship between the moment strength and applied central peak load estimations using yieldline analysis is given as follow; (3) al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 where m is the nominal flexural strength moment for the slab and p is the applied load. table (5) shows the experimental peak load and flexural capacity calculated from a yield-line analysis for each specimen. the load, normalized by the slab flexural capacity from the yield-line analysis, versus deflection response for the test specimens is presented in fig. (11).the result from a yield-line analysis gives a lower bound estimation of the strength of the slab due to the absence of the membrane action. 8. influence of patch load area on deflection capacity the effect of the patch area shape in the deflection capacity of the test specimens was evaluated through the ratio δr/δrc, where δrc refers to the deflection of the specimen s1c with circular patch load area at peak load. δr, on the other hand, is the deflection at peak load for each test specimen. the calculated values of δr, δrc and δr/δrc are given in table (6). among all specimens, specimens s3r exhibited the best performance with an increase of 36% in deflection capacity compared to specimens s1c. 9. energy absorption energy absorption capacity of the test specimens was evaluated based on the area under the normalized punching shear stress versus deflection response (cheng, 2009), where the vertical axis was selected as the normalized shear stress, ( √ )⁄ and the horizontal axis represents the vertical deflection (fig. (12)), where; bo = perimeter of critical section for shear (mm), d = distance from extreme compression fiber to centroid of longitudinal tension reinforcement (mm) and specified compressive strength of concrete cylinder (mpa). table (7) summarizes the energy values were calculated according to the area under the curves shown in fig. (12) for each specimen. it can be noticed that the specimens with rectangular patch area had better energy absorption ability. 10. load-rotation relationship the ductility of slabs failing in punching shear can be obtained by considering a suitable loadrotation relationship for the slab. (muttoni, 2003) proposed semi-empirical formal to derive the load-rotation relationship for the slab as below; ( ) ⁄ (2) where l is the span of the slab, mrd is the flexural capacity of the slab in the column region reduced by the strength reduction factor, specified compressive strength of concrete cylinder ; fy is yield strength of bending reinforcement; vd load during testing , d = distance from extreme compression fiber to centroid of longitudinal tension reinforcement and ψ is slab rotation. still further, the following failure criterion was proposed for punching shear failures in slabs without transverse reinforcement (muttoni, 2008): ( √ ) ⁄ ( ) (3) al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 where dg0 is a reference diameter of the aggregate admitted as 16mm; dg is the maximum diameter of the aggregate used in the concrete slab, in mm. finally the ductility of the reinforced concrete slab under punching shear can be obtained by using curvature ductility as follow; (4) where is the curvature at the end of the post elastic range and is curvature at the first yield. in the present study the value represents the curvature value for the intersection point between the failure criterion from equation (2) and the load-rotation from equation (1), as define shown in fig.(13). the load-rotation curves and failure criteria for tested slab have been shown in fig. (14).accordingly, the ductility values calculated and show in table (8) for tested slabs. 11. conclusions the results and conclusions are summarized in the following: 1. with reference to punching shear strength, the experimental results presented within this paper confirm the influence of the patch area shape on the strength and deformation capacity of slabs. 2. validity of the experimental results were checked by analyzing the tested slabs by finite element method under cracking load. the central deflection results obtained by the finite element method are found to compare well with those obtained experimentally. 3. the published failure criterion simultaneously determines the punching load and the rotation capacity of the slab and its ductility. 4. circular column is needed to be use in order to preclude splitting failure in the slabs. 5. the shape of patch load area had a significant influence on the ductility for reinforced concrete slab. higher ductility has been observed for slab with circular shape of patch load area. 6. the behavior of punching shear reinforcing systems is slightly influenced by the shape of patch load area. 7. the yield analysis and experimental results shows that the flexural behavior is slightly influenced by the shape of patch load area for reinforced concrete slab. 8. the slab with rectangular shape of patch area had better energy absorption ability because of the larger plastic rotations sustained, since this slab has shorter the length of span in direction that moments are being applied. this specimen showed larger deformation capacity. 12. references 1. american concrete institute, aci 421.1r-08, 2008,"guide to shear reinforcement for slabs”, reported by joint aci-asce committee 421. 2. american concrete institute, aci 421.1r-99, 1999,"shear reinforcement for slabs”, reported by joint aci-asce committee 421. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 3. american concrete institute, aci committee 318, 2008,"building code requirements for structural concrete (aci 318m-08) and commentary", forming ton hill, michigan, 107 pp. 4. astm standards: a615/a615m-03, 2003, "standard specification for deformed and plain billet-steel bars for concrete reinforcement", astm international, 100 barr harbor drive, west conshohocken, pa 19428-2959, usa. 5. british standards institution, 1983, "method for determination of compressive strength of concrete cubes (bs 1881: part 116: 1983)", british standards institution, london. 6. british standards institution, 1997, "code of practice for design and construction (bs 8110: part 1: 1997)", british standards institution, london. 7. cheng, m. and montesinos, g., 2010, "evaluation of steel fiber reinforcement for punching shear resistance in slab-column connections—part i: monotonically increased load", aci structural journal, v. 107, no. 1, january-february. 8. cheng, m., 2009,"punching shear strength and deformation capacity of fiber reinforced concrete slab-column connections under earthquake-type loading", ph.d. thesis, department of civil engineering, the university of michigan, usa. 9. corley, w. g., and hawkins, n. m., 1968, "shear head reinforcement for slabs", aci journal, proceedings v. 65, no. 10, oct., pp. 811-82. 10. dilger, w. h., and ghali, a., 1981, "shear reinforcement for concrete slabs", journal of the structural division, asce, v. 107, no. st12, pp. 2403-2420. 11. etabs plus version 9.7.1, 2010, "extended 3-d analysis of building systems", computer and structures, inc., berkeley, ca, usa. 12. hawkins, n. m.; mitchell, d.; and sheu, m. s., 1974, "cyclic behavior of six reinforced concrete slab-column specimens transferring moment and shear", progress report 1973-74 on nsf project gi-38717, department of civil engineering, university of washington, seattle, wa, sept. 13. islam, s., and park, r., 1976, "tests of slab-column connections with shear and unbalanced flexure", journal of the structural division, asce, v. 102, no. st3, pp. 549-569. 14. muttoni, a., 2003, "shear and punching strength of slabs without shear reinforcement", beton-und stahlbetonbau, v. 98, no. 2, berlin, germany, pp. 74-84. (in german). al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 11 15. muttoni, a.,2008, "punching shear strength of reinforced concrete slabs without transverse reinforcement", aci structural journal, farmington hills, mich., vol. 105, no. 4, pp.440-450. 16. safe version 12.3.1, 2010, "slab analysis by the finite element method", produced and distributed by computers & structures, inc. ,1995 university avenue, berkeley, california 94704, usa. 17. standards association of new zealand, 1982, "code of practice for commentary on: the design of concrete structures (nzs 3101:1982, part 1 and 2)", standard council, new zealand. table 1: mix proportions cement kg/m 3 sand kg/m 3 gravel kg/m 3 water kg/m 3 570 680 1040 143 table (2): specimen details specimen dimensions of slab specimen (lengthxwidthxthickness)mm patch load shape patch load area dimension (mm) bottom reinforcement in each direction (no.-mm ø) s1c 450x450x30 circular 22 dia. 4-ø5 s2s 450x450x30 square 25x25 4-ø5 s3r 450x450x30 rectangular 15x32.5 4-ø5 table (3): comparison of central deflection at cracking stage specimens cracking load(kn) experimental δcr(mm) theoretical δcr (mm) δexp./ δtheo. s1c 5 0.74 0.72 1.03 s2s 7 0.85 1.12 0.76 s3r 4 0.56 0.51 1.10 table (4): the cracking load, failure load and failure mechanism specimen cracking load(kn) failure load(kn) failure mechanism s1c 8 17 punching shear s2s 7 16.5 punching shear(splitting) s3r 4 16.5 punching shear(splitting) al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 18 table (5) strength estimations using yield-line analysis specimen peak load(kn) peak load for yield-line analysis(kn) test/yield-line s1c 17 10.7 1.59 s2s 16.5 10.7 1.54 s3r 16.5 10.7 1.54 table (6): comparison of deflection capacities specimens δr (mm) δr/δrc s1c 10 1.0 s2s 12.5 1.25 s3r 13.6 1.36 table (7): energy absorption specimens normalized energy energy/s1c energy s1c 6.27 1.0 s2s 6.44 1.03 s3r 6.74 1.07 table (8): ductility specimens ψm % ψy % µψ s1c 1.215e-04 6.379e-06 19.05 s2s 1.162e-04 10.005e-06 11.61 s3r 1.162e-04 9.9234e-06 11.71 4-ø5 each way 400 mm 450 mm loading block (patch area) 4 0 0 m m 4 5 0 m m x x loading block (patch area) smooth rod (25 mm) 3 0 m m (a) plane view (b) section x-x 4-5 mm each way fig. (1): details of a typical model of slab with reinforcement. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 89 fig. (2): test setup. fig.(3): support of the test setup. fig. (4): one dial gauges are below the center of slabs. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 88 g fig.(5): three dimensional plane shell element ( aaxial stress, bbending stress, ctotal in-plane stress, dshear stress, etwisting stress, ftotal shear stress, gstress conventions for thin plane shell element). simply supported edge s im p ly s u p p o rt e d e d g e s im p ly su p p o rte d e d g e simply supported edge 4 5 0 m m 450 mm fig. (6): mesh modelling of a typical slab. fig. (7): cracking pattern on the bottom surface of a model slab. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 88 0 2 4 6 8 10 12 14 deflection(mm) 0 2 4 6 8 10 12 14 16 18 l o a d ( k n ) circular shape of patch area square shape of patch area rectangular shape of patch area pcr for circular shape of patch area pcr for square shape of patch area pcr for rectangular shape of patch area fig. (8): load-deflection curves of tested model. 0 0.0005 0.001 0.0015 0.002 0.0025 curvature 0 100 200 300 400 500 600 m o m e n t (n .m ) fig. (9): moment curvature curves. 3 0 m m section dimensions and properties used in moment curvature calculations. 4-5 mm each way 450 mm al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 88 simply supported edge loading block (patch area) s im p ly s u p p o rt e d e d g e s im p ly su p p o rte d e d g e simply supported edge m 4 5 0 m m 450 mm m m 25 mm 2 5 m m fig. (10) assumed yield-line pattern for test specimens. 0 4 8 12 16 deflection (mm) 0 0.4 0.8 1.2 1.6 2 p te st /p y ie ld -l in e circular shape of patch area square shape of patch area rectangular shape of patch area fig. (11) normalized load versus deflection response. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 88 0 4 8 12 16 deflection (mm) 0 0.2 0.4 0.6 0.8 1 n o rm al iz ed p u n ch in g s h ea r s tr es s circular shape of patch area 0 4 8 12 16 deflection (mm) 0 0.2 0.4 0.6 0.8 1 n o rm al iz ed p u n ch in g s h ea r s tr es s square shape of patch area 0 4 8 12 16 deflection (mm) 0 0.2 0.4 0.6 0.8 1 n o rm al iz ed p u n ch in g s h ea r s tr es s rectangular shape of patch area fig. (12): ( √ )⁄ and the vertical deflection curve. al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 88 fig. (13): design procedure to check the punching strength of a slab (muttoni, 2008). al-qadisiya journal for engineering sciences, vol. 7……no. 1 ….2014 88 0 4e-005 8e-005 0.00012 0.00016 0.0002 ø[%] 0 4 8 12 16 20 p u n c h in g l o a d (k n ) circular shape of patch area load-rotation curve of the slab failure criterion 0 4e-005 8e-005 0.00012 0.00016 0.0002 ø[%] 0 4 8 12 16 20 p u n c h in g l o a d (k n ) square shape of patch area load-rotation curve of the slab failure criterion 0 4e-005 8e-005 0.00012 0.00016 0.0002 ø[%] 0 4 8 12 16 20 p u n c h in g l o a d (k n ) rectangular shape of patch area load-rotation curve of the slab failure criterion fig. (14): load-rotation curves and failure criteria for tested slabs. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 23 modidication of leachet characteristcs in landfill using mixxture of lime and sawdust waste prof.dr. dheyaa wajid abud. dr. mohammed ibrahem basheer al-ubaidy yousef a. jassim dr.dheyaa@googlemail.com mohibrbas1@yahoo.com joe.iraq89@gmail.com environmental engineering dep, collage of engineering, al-mustansiriya university. received 28 june 2015 accepted 23 november 2015 abstract landfill bioreactor is a modified technique comparing with the conventional landfill processes due to its ability to reduce time for decomposition and enhancing the biogas generation. the basic goal of this paper is to investigate the performance of a three lab-scale bioreactors under anaerobic conditions. three types of reactors differ in its internal composition were experimented ,bentonite clay was used as a cover material. first reactor was filled with organic solid waste only; second reactor was filled with a mixture of organic solid waste, lime and sawdust, while the third reactor was filled with mixture of solid waste and lime. leachate characteristics traced includes ph, ec, tds, tss, heavy metals (cr, fe, mn, zn, and mo), sulfate so -2 4 and phosphate po -3 4. experiments were conducted from october 2014 to march 2015, results shows a significant variation in removal efficiency for each reactor, heavy metals removal for the first reactor was (mn 58.6%, cr 13.4%, mo 0%, zn 27.2%, fe 58.6%),and the second reactor removal efficiency was (mn 77.2%, cr 67.5%, mo 69.19%, zn 67.9%, fe 56.7%), while for the third reactor was (mn 30.1%, cr 13.8%, mo 18.48%, zn 29.8%, fe 70%). the results show that the solid waste, lime and sawdust enhanced the removal of heavy metals in the 2 nd reactor which gave best removal efficiency for heavy metals. while the lime addition in the 3 rd reactor increase the removal efficiency of iron to 70%. it can be conclude that this modified landfill bioreactor enhance leachate characteristics and so enhancing the solid waste stabilization. keywords: leachate, landfill, bioreactor, lime, sawdust, anaerobic. الخشب نشارةو نفايات الجير من خليط باستخدام النفايات مكب عصارة خواص تعديل جيد جاسمأ.م.د ضياء واجد عبود م.د. محمد ابراهيم بشير العبيدي يوسف عبد الم al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 24 ة .الخالص الوقت تقليل على لقدرته نظرا التقليدية النفايات طمر عمليات مع مقارنةمعدل لعملية الطمر الصحي أسلوب هو حيويال مفاعلال حيوية مفاعالت ثالثة أداء في للتحقيق هو الورقة هذه من األساسي الهدف. الحيوي الغاز توليد تعزيز وكذلك لتحللالمطلوب لعمليات ا البنتونيت طين استخدامو لجميعها فقد تم الداخلي تكوينها ، تختلف هذه المفاعالت الحيوية الثالثة فيالالهوائية الظروف تحت مختلفة العضوية الصلبة النفايات من خليط معتم تشغيله الثاني المفاعل فقط، العضوية الصلبة النفايات مع األول المفاعل شغل. غطاء كمادة التي تم تتبعها العصارة خصائص. والجير الصلبة النفايات من خليط مع الثالث المفاعل تم تشغيل حين في الخشب، ونشارة والجير (، cr, fe, mn, zn, moة، التوصيلية الكهربائية، المواد الذائبة الكلية، المواد العالقة الكلية، المعادن الثقيلة )الحموض درجةشملت soالكبريتات ) -2 po(، و الفوسفات ) 4 -3 4.) من المفاعالت مفاعل لكل اإلزالة كفاءة في كبير تفاوتاطهرت النتائج ،4102 مارس إلى 4102 أكتوبر منللفترة التجارب أجريت اما ,(mn 58.6%, cr 13.4%, mo 0%, zn 27.2%, fe 58.6%) األول مفاعللل الثقيلة المعادن إزالةكفاءة كانت ،الثالث لمفاعلكفاءة االزالة في ا أن حين في ، ,(mn 77.2%, cr 67.5%, mo 69.19%, zn 67.9%, fe 56.7%)المفاعل الثاني الصلبة، النفاياتمزيج أن النتائج أظهرت. .(mn 30.1%, cr 13.8%, mo 18.48%, zn 29.8%, fe 70%) كان الثالث الثالث ادى الى زيادة المفاعل فيفقط الجير إضافة أن حين في. الثقيلة المعادن إزالة في المفاعل الثاني عززت الخشب ونشارة والجير من خالل نتائج البحث التوصل الى استنتاج الى ان التعديالت المقترحة للتركيبة الداخلية للمفاعالت يمكن٪. 01 إلى الحديد إزالة كفاءة .الصلبة النفايات تثبيت تعزيز و بالتلي العصارة خصائص تعزيز في افعاليته قيد البحث حسنت nomenclature. ec: electrical conductivity. ph: potential hydrogen. tds: total dissolved solids. tss: total suspended solids. 1. introduction. the landfill is the most common method for solid waste disposal and it is like other methods of treatment have advantages and disadvantages. uncontrolled leachate and gas production are the major disadvantages as well as the public and aesthetic problems resulted from open dump solid waste disposal (chart, 2004). many researches were done in order to minimize the problems associated with landfill practices (yuen, 2001). in order to improve knowledge of landfill behavior and decomposition processes of msw, there has been a strong interest in upgrade existing landfill technology from a storage/containment concept to a process-based approach, in other words as a bioreactor landfill (mostafa, 2002). bioreactor is any system boosts the biological activity in a specific environment, and so bioreactor landfill is the technique that employs modification on the process of the conventional landfill either by leachate recirculation into msw fills with or without oxygen supply or with chemicals to enhance the biological processes and reduce stabilization time needed for organic waste. the waste is considered stabilized when leachate is no longer pollution hazard, gas production and settlement is negligible (borglin, 2004). the use of bioreactor landfill will significantly increase the organic solid waste decomposition over the ordinary organic solid waste landfill (swati, 2007). the anaerobic digestion process takes place in an airtight container, known as a digester. the first stage of anaerobic digestion is a chemical reaction called hydrolysis (shefali, 2002), where complex organics particles are separated into basic sugars, amino acids, and fatty acids with the addition of hydroxyl groups. this is followed by three biological processes: al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 25  acidogenesis further broken down by acidogenic bacteria into simpler molecules, volatile fatty acids (vfas) occurs, producing ammonia, co2 and hydrogen sulfide as byproducts.  acetogenesis the molecules particles from acidogenesis are further processed by microscopic organisms called acetogens to create co2, hydrogen and acetic acid (ljupka, 2010).  methanogenesis methane, co2 and water are produced by bacteria called methanogens. in order to maximize digestion, ph level should be kept within (5.5-8.5) and the temperature between 3060°c, in order to maximize digestion rates (amin, 2012). in this paper a lab-scale solid waste bioreactor landfill will be used. modification of the landfill bioreactor will be done by mixing waste with specific materials to improve the performance of solid waste stabilization and enhancing the leachate characteristics. 2. material and methodology. three lab-scales of bioreactors (fig 1) have been designed and constructed in al-mustansiriya university, college of engineering. 2.1. structure and filling of reactors. 2.1.1. first reactor. first reactor made of ductile iron pipe of (1.3m) height and (0.4m) diameter, the effective height of solid waste was (1m). the reactor was underlying by (15cm) gravel layer for drainage purposes and pvc pipe for leachate collection as in fig (2). the solid waste in reactor was separated by a strainer from the gravel layer. the reactor was sealed by (15cm) bentonite clay as cover material, bentonite are excellent sealants and absorbents, so it acts as an excellent barriers for landfills and toxic waste repositories (haydn, 2002). table (1) and (2) shows the chemical and physical characteristics of bentonite. the reactor was well lidded from top to ensure that the anaerobic conditions will occur. the reactor filled with (84kg) of dry and well compacted organic solid waste (corrupted fruits and vegetables), the waste density was 668.45kg/m 3 , the compaction was applied in order to increase the dry density which significantly speed up the degradation processes (chart, 2004). 2.1.2 . second and third reactor. the frame structure of the second and third reactors is identical, it made of ductile iron pipe, height and diameter are (1.1m) and (0.3m) respectively, the reactors were underlying by (15cm) of gravel layer and sealed from top by (15cm) bentonite. the solid waste effective height was (80cm) with drainage pipe for leachate collection as in figure (3). second reactor was filled with (50kg) organic solid waste, 3kg of sawdust and 2.211 kg of lime. the purpose of adding the saw dust is to reduce the volume of organic compound in the reactor as well as to investigate its behavior as adsorbent media. lime was added in the 2 nd and 3 rd reactor to minimize the acidic affect on microorganisms activities, lime proven a good capability in ph adjusting (abdullahi, 2012), as well as the lime will reduce the emission of co2 and mitigate the greenhouse gases according to equation (1) (guang, 2000). the third reactor was filled with (50kg) organic solid waste and (4.422 kg) of lime to find out the effect of sawdust absence. table (3) describes the specification and filling mixture of the three reactors. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 26 (1) 2.2. monitoring of bioreactor landfill. the produced leachate was analyzed for parameters of ph, sulphate so -2 4 , phosphate po -3 4, ec, fe +2 , zn +2 , cr +3 , mn +2 , mo +2 , total dissolved solids tds and total suspended solid tss. standard methods for wastewater examination (eaton, 2005) and spectrophotometers (hach) were used. 3. results and discussion. 3.1. the effect of lime on ph. the initial ph values differ in each reactor due to the lime addition and its effects on ph value during the study period. table (4, 5 and 6) describes the physiochemical characteristics of leachate generated through the study period from the 1 st , 2 nd and 3 rd reactors, respectively. the first reactor has initial ph of 4.9 and then increase slightly to 6.3 after 6 months of operation due to acid formation phase. ph value in 1 st reactor kept under ph value 6.4 which is the minimum optimum value for the anaerobic digestion (fabien, 2003). while the ph initial value in 2 nd reactor was 6.07 and increased to 7.02 in two months due to the addition of 2.211 kg of lime. in 3 rd reactor the initial ph was 7.1 due to the addition of 4.422 kg lime. lime is considered as a ph regulator due to its effect in breaking down the organic matters and neutralizes acidity (edson, 2011). 3.2. removal of heavy metals. initial leachate characteristics clearly showing that the leachate exhibited significant value of heavy metals such as mo +2 , fe +2 and mn +2 . and the higher values of that three elements was in the 2 nd reactor which are 600mg/l, 277.7mg/l and 237.7mg/l for mo +2 ,fe +2 and mn +2 respectively. in this study, fe +2 values have been significantly reduced throughout the study period as shown in figure (4). the final effluent concentration of fe +2 was varies among the three reactors, with 85mg/l, 120mg/l and 70 mg/l for the 1 st , 2 nd and 3 rd reactor, respectively. the optimum removal of fe +2 was in 3 rd reactor with 70%. the highest removal was 70% for 3 rd and lowest removal for the 2 nd reactor which is very close to the removal of 1 st reactor which are 56.7% and 58.8%, respectively. the 4.422kg of lime addition in the 3 rd reactor makes ph in range of (7.1-9.2) which increase the removal of iron as shown in figure (4), it’s observed that the increase in metals removal is related to the increase in ph (hamidi, 2004), such result is due to the fact that most metallic elements are soluble in an acidic environment. 2 nd reactor leachate have the highest initial value for mn +2 and mo +2 , with 258.9mg/l and 600.3mg/l respectively, the final effluent was significantly reduced to 65mg/l and 185 mg/l for mn +2 and mo +2 , respectively with ph was in range of (6.07-8.8) as shown in figure (5). 2 nd reactor was more efficient in removal of mn +2 and mo +2 from leachate. the removal efficiency of mn +2 and mo +2 in 2 nd reactor was 77.2% and 69.19 %, respectively, while the removal efficiency in 1 st and 3 rd reactor was 23% mn +2 , 0% mo +2 and 30.1% mn +2 , 18.48% mo +2 , respectively. sawdust is a more suitable adsorbent compared to rice husk in the removal of heavy metals from the simulated landfill leachate (agbugui, 2015). sawdust was capable of adsorbing mn +2 and mo +2 , normally mo +2 is anion forming metalloid and therefore like chromate, arsenic, uranium and vanadium, should be adsorbed best with ph value between (5-7) (chistensen, 2010). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 27 the polymeric material in sawdust is lignin, tannins or other phenolic compounds. from the nature of the material that are efficient in capturing heavy metal ions especially cr +3 (agbugui, 2015). in this study the initial values of cr +3 and zn +2 in 2 nd reactor was 9.4mg/l and 19.3 mg/l, respectively, which is higher than other reactors. the removal efficiency of both metals in the 2 nd reactor was 67.5% and 67.9%, respectively, as shown in the figure (6) which is the best removal among the other reactors throughout the study period. 3.3. removal of so -2 4 and po -3 4. the initial value of so4 in 2 nd reactor was 1206.7 mg/l which is the highest while the initial value of so -2 4 for the 1 st and 2 nd was 262.4mg/l and 343.3 mg/l, respectively. the so -2 4 reduced significantly to 253.2 mg/l in 2 nd reactor as shown in figure (7), while the effluent value from 1 st and 3 rd reactors was 200 mg/l and 130 mg/l. the removal efficiency of so -2 4 in the 2 nd reactor was 79%. the initial value of po -3 4 in 3 rd reactor was 24.9 mg/l and the effluent was 15.2 mg/l. the 3 rd reactor removed the po -3 4 efficiently with a removal efficiency of 64.3% as shown in figure (8). the decline in phosphate concentration may due to the phosphate assimilation by microorganisms. 3.4. removal of tss. the tss initial value in the 2 nd was higher than other reactors with 365 mg/l which decreased to 231mg/l in the first three weeks, then tend to increase to 470 mg/l, the final effluent throughout this study was 58 mg/l. the removal efficiency in the 2 nd and 3 rd reactors was 84.11% and 84.5% which indicates that both reactor have same behavior in removing tss. figures (9), (10) and (11) shows tss concentration variation with time in 1 st ,2 nd and 3 rd reactors respectively, the fluctuation in tss values appear in the previous figures may related to the variation of microorganism activity in breaking down organic matters, which effected by many factors such as ph and temperature. 4. conclusion. based on the previous results in the present study, it can be concluded the following: 1removal of heavy metals, phosphate and sulphate can be influenced significantly by mixture composition of solid waste in bioreactor landfill. 21 st reactor which was containing solid waste only like an ordinary landfill was suffering from insignificance leachate enhancement. 3designed solid waste mixture in 2 nd reactor provided adsorbent media (sawdust) and ph adjustment material (lime), and such designed mixture enhanced the removal efficiency of heavy metals and sulphate. 43 rd reactor although it was less efficient in pollutant removal than 2 nd reactor, however this reactor was more efficient in pollutant removal than 1 st reactor and such result prove the positive effect of lime addition as a ph regulator for microorganism activity. 5the results showed that the 2 nd reactor have optimum removal for heavy metals and sulphate, which makes the 2 nd reactor best choice among the other two reactors. fe +2 was removed more efficiently by 3 rd reactor. both 2 nd and 3 rd reactors were efficiently removed tss from leachate. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 28 a recommendation for future studies is the investigation the influence of leachate recirculation percent and ratios of sawdust and lime on the performance of reactors. 5. references. [1] abdullahi, m. evuti, aloko d. folorunsho, baba g. agaie and mohammed jibril. “predictive model for lime dosage in water treatment plant” international journal of scientific and research publications, volume 2, issue 12, december (2012). [2] agbugui pa. and nwaedozie jm. “adsorption of heavy metals from simulated landfill leachates unto composite mix of agricultural solid wastes” iosr journal of applied chemistry (iosr-jac), volume 8, issue 2 ver. i. feb (2015), pp 49-54. [3] amin m, hamidi a, nastaein q. zaman and shuokr q aziz, " a review on anaerobic digestion, bio-reactor and nitrogen removal from wastewater and landfill leachate by bioreactor” advances in environmental biology, 6(7): 2143-2150, (2012). [4] borglin, s. e., hazen, t. c., oldenburg, c. m., zawislanski p. t. “comparison of aerobic and anaerobic biotreatment of municipal solid waste” technical paper. j. air & waste manage. assoc. 54:815–822. (2004). [5] chart chiemchaisri, wilai chiemchaisri, c. visvanathan, josef tränkler . “bioreactor landfill for sustainable solid waste landfill management” report published by faculty of engineering kasetsart university, 50 phaholyotin road,chatuchak bangkok 10900, thailand, (2004). [6] chistensen t.c, michael vendrp and sofie van eemen “removing sb, mo, se, u, and ba from wastewater and leachate” 2 nd international conference on hazardous and industrial waste management, några intressant föredrag kreta 5-8 october (2010). [6] eaton, rice and baird “standard methods for the examination of water and wastewater”, 21st ed. american public health association, washington, d.c. (2005). [7] edson m, ayo s. afolabi, ambali s. abdulkareem and freeman ntuli “effect of ph on the recovery and grade of base metal sulphides (pgms) by flotation”, proceedings of the world congress on engineering and computer science (2011) vol ii, san francisco, usa. pp 609-612. [8] fabien, monnet. “an introduction to the anaerobic digestion of organic waste”. biogas max. remade scotland, november (2003). accessed may 20, 2015. [9] guang g. li, tim c. keener, antoinette w. stein, soon j. khang “co2 reaction with lime during so2 removal with convective pass sorbent injection and high temperature filtration” environ engg and policy 2, (2000), pp 47-56. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 29 [10] hamidi abdul aziz, mohd suffian yusoff, mohd nordin adlan,, nurul hidayah adnan, salina alias “physico-chemical removal of iron from semi-aerobic landfill leachate by limestone filter” waste management, volume 24, issue 4, (2004), pp 353–358. [11] haydn murray “industrial clays case study”, report was commissioned by the mmsd project of iied, no 46, (2002). [12] ljupka arsova, “anaerobic digestion of food waste: current status, problems and an alternative product”, thesis submitted to department of earth & environmental engineering, columbia university, may (2010). [13] mostafa warith “bioreactor landfills: experimental and field results” waste management, volume 22, issue 1, (2002), pp 7–17. [14] shefali verma, “anaerobic digestion of biodegradable organics in municipal solid wastes”, thesis submitted to department of earth & environmental engineering, columbia university, may (2002). [15] swati m., obuli p. karthikeyan, kurian joseph, and nagendran r.,“ landfill bioreactor – a biotechnological solution for waste management”, journal of scientific and industrial research, vol. 66, no. 8, (2007), pp. 589-674. [16] yuen s t s ”bioreactor landfills – do they work? “ geoenvironment 2001: 2nd anz conf on environmental geotechnics (newcastle, australia) 28-30 november (2001). http://people.eng.unimelb.edu.au/stsy/others/papers/geoenvironment2001_sy.pdf. table (1): chemical composition of bentonite comp. sio2 al2o3 fe2o3 cao mgo na2o percentage 56.77 15.67 5.12 4.48 3.42 1.11 comp. k2o p2o so2 cl lio3 percentage 0.6 0.65 0.59 0.57 9.49 table (2): physical properties bentonite. clay type surface area (m 2 /g) density (kg/m 3 ) oil retention (%) ph adsorption of water vapor % bentonite 220 750 35 10.1 11.8 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 30 table (3): specification and filling waste mixture of the three reactors. reactor no. components 1 2 3 organic waste weight(kg) 84 50 50 lime 2.211 4.422 sawdust (kg) 3 density of mixture ( kg/m 3 ) 668 770 820 cover material bentonite bentonite bentonite table (4): characteristic of leachate from 1 st reactor. item time, weeks 1 4 9 10 27 29 30 34 ph 4.94 5.22 6.06 6.26 6.3 7.46 6.05 6.22 mn +2 mg/l 56.93 49.23 97.2 95.33 115.2 51.7 62.56 43.68 zn +2 mg/l 4.715 3.67 7.98 9.44 9.27 4.29 4.78 3.43 so -2 4 mg/l 262.44 195.9 456 346.6 486 209 220.8 200 po -3 4 mg/l 22.7 38.4 35.4 33 23.04 11.33 15.08 9.36 tss mg/l 279 400 350 621 314 241.9 309.5 600 mo +2 mg/l 112.5 95.031 192 173.3 350 310 224.48 145.6 cr +3 mg/l 2.11 1.61 3.27 4.33 3.335 2.3343 2.8 1.83 fe +2 mg/l 205.4 306.9 249.6 330 191.7 90.68 110.77 85 ec μs/cm 2006 3665 16004 17505 29983 31075 32678 18660 tds ppm 1059 1920 8241 9014 15532 16115 17112 9325 table (5): characteristic of leachate from 2 nd reactor. item time, weeks 1 4 9 10 27 29 30 34 ph 6.07 6.4 6.72 7.02 7.5 8 8.3 8.8 mn +2 mg/l 285.09 119.7 62.8 80.6 55.3 82.5 82.8 65 zn +2 mg/l 19.3 7.29 5.36 7.06 4.69 6.38 7.56 6.2 so -2 4 mg/l 1206 423 290.18 346.6 224 341 306 253.2 po -3 4 mg/l 25.1 19.4 8.4 29.6 12.11 16.28 19.98 15.2 tss mg/l 365 231 360 470 347.9 388 86.7 58 mo +2 mg/l 600.3 451 401 321 250 310.2 257.4 185 cr +3 mg/l 9.457 3.798 2.083 2.903 3.55 3.784 3.834 3.07 fe +2 mg/l 277.7 181.2 238.2 280.8 90.1 140.75 140.94 120 ec μs/cm 3249 3860 27859.5 28862.5 44010 37235 46890 19335 tds ppm 1691 2009 14500 15022 22512 19173 23400 9660 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 31 table (6): characteristics of leachate from 3 rd reactor. figure (1): 1 st , 2 nd and 3 rd reactors. item time, weeks 1 4 9 10 27 29 30 34 ph 7.1 7.5 7.8 8 8.2 8.31 8.8 9.2 mn +2 mg/l 70.09 114.24 79.4 95.33 70 72.75 53.2 49 zn +2 mg/l 5.41 8.26 6.41 7.8 3.99 4.8 3.5 3.8 so -2 4 mg/l 343.37 443.64 322.42 346.6 308 292.5 196 130 po -3 4 mg/l 24.9 31.6 10.6 33 11.2 12.3 9.94 8.9 t.s.s mg/l 292 394 416 472 200 147.27 75.94 45.04 mo +2 mg/l 330 205.2 160 200 301 270 277.2 269 cr +3 mg/l 2.76 4.87 2.87 4.33 3.225 3.187 2.506 2.38 fe +2 mg/l 237.7 301.8 282.7 330 110.9 122.25 90.94 70 ec μs/cm 2628 4750 18933 23791.8 42254 34497 36540 24434.8 tds ppm 1371 2500 9965 12522 21613 17955 18214 12213.8 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 32 figure (2): scheme of 1 st bioreactor. figure (3): scheme of 2 nd and 3 rd reactors. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 33 figure (4): variation of fe +2 with ph increasing, 3 rd reactor. figure (5): variation of mo +2 and mn +2 with ph, 2 nd reactor figure (6): zn +2 and cr +3 removal efficiency, 2 nd reactor y = 75265e-0.754x r² = 0.7006 0 50 100 150 200 250 300 350 400 7 7.5 8 8.5 9 9.5 10 f e + 2 m g /l ph y = 60.997x2 953.32x + 3766.4 r² = 0.7123 y = 55.656x2 950.37x + 4280.6 r² = 0.9032 0 100 200 300 400 500 600 700 6 6.5 7 7.5 8 8.5 9 c o n c e n tr a ti o n m g /l ph mn mo 0 10 20 30 40 50 60 70 80 90 0 5 10 15 20 25 30 35 % r e m o v a l time, weeks zn cr al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 34 figure (7): variation with time, 3 rd reactor figure (8): po -3 4 variation with time, 2 nd reactor. figure (9): tss variation throughout time, 1 st reactor. y = 904.19x-0.374 r² = 0.7937 0 200 400 600 800 1000 1200 1400 0 5 10 15 20 25 30 35 40 s o 4 -2 , m g /l time, weeks y = 27.965e-0.033x r² = 0.6253 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 p o -3 4 , m g /l time, weeks 0 100 200 300 400 500 600 700 0 1 2 3 4 5 6 7 8 9 t s s , m g /l time, weeks al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 35 figure (10): tss variation with time, 2 nd reactor. figure (11): tss variation throughout time in the, 3 rd reactor 0 50 100 150 200 250 300 350 400 450 500 0 1 2 3 4 5 6 7 8 9 t s s , m g /l time, weeks 0 50 100 150 200 250 300 350 400 450 500 0 1 2 3 4 5 6 7 8 9 t s s , m g /l time, weeks al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 using of xfem with meshing type-t3 for orthotropic fgm plate with a center crack parallel to the material gradation under fixed grip loading msc. hassanein ibraheem khalaf & ass. prof. dr. ameen ahmed nassar mechanical engineering department college of engineering university of basrah basrah / iraq received 18 january 2015 accepted 7 may 2015 abstract an improved approach for modeling discrete cracks in two-dimensional anisotropic functional graded materials fgms by xfem is described. a general node meshing type-t3 with sub-triangle technique for enhancing the gauss quadrature accuracy near the crack is applied to increase the accuracy of numerical results. also, the useful incompatible interaction integral method (m-integral method) is used to calculate the stress intensity factors. numerical simulations have proved that provides accurate results by less number of nodes (dofs) in comparison with reference. the results of lefm (liner elastic fracture mechanics) have been compared with the reference results, showing the reliability, stability, and the efficiency of present meshing of xfem. matlab program (m-file) is used to solve the aim of this paper. keywords: xfem, anisotropic functional graded materials, interaction integral, stress intensity factors. ه تحتوي شرخ حيلصف t3استخدام طريقه العناصر المحددة المطورة مع شبكة توزيع عقد نوع متدرجه الخواص المعدنيه وظيفيا وتحت حمل انفعال ثابت متمركز و أستاذ مساعد دكتور امين احمد نصار مدرس مساعد حسنين ابراهيم خلف قسم الهندسة الميكانيكية كلية الهندسة جامعة البصرة العراق –البصرة الملخص لنمذجه الشروخ في التطبيقات ثنائيه االبعاد وفي معادن xfemالبحث يستعرض استخدام منهاج تحسين الطريقه العدديه المطوره عددي عند منطقه الشرخ تقنية المثلث الفرعية لتوزيع نقاط التکامل ال، و t3متدرجه الخواص وظيفيا. لزيادة دقه الحل، شبكه عقد نوع لحساب معامالت تركيز االجهاد. incompatible interaction integralطريقه التفاعل التعارضي تم تطبيق ا. كذلك تم استخدمه نتائج مشاكل الكسر الميكانيكي الخطي. تم مقارنة بالمقارنه مع عدد من المصادر التمثيل العددي الجديد دقته باقل عدد من العقداثبت al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 lefm مع المصادر ذات العالقه، والتي تبين االعتمادية، واالستقرار، وكفاءة الطريقه العدديهxefm مع التقنيات االخرى لحل هدف هذا البحث. ماتالبتم استخدام برنامج المستخدمه. 1. introduction today, functionally graded materials (fgms) are very significant materials to use in many branches of engineering applications in aerospace, automobile, medical equipments, and turbine industries. a formulated concept of functionally graded materials (fgms) was proposed in 1984 by material scientists in sendai area, japan, as a means of preparing thermal barrier materials, and a coordinated research was developed in that country since 1986. the idea, that continuously changes in the composition, microstructure, porosity, etc., of these materials resulting in gradients in such properties as mechanical strength and thermal conductivity, has spreaded world-wide in the recent research [1]. where in these materials smoothly continuously change in microstructure porosity, bonding, etc resulting in gradients in such properties as mechanical strength and thermal conductivity, has spread to use fgms in different applications rather than use of the ordinary composites by improving a number of useful, relevant properties against the problem of interface regains. clearly and recently, the use of fgms rather than composites materials has been developed such as shown in [2-4]. various method have already presented to the fracture analysis of functionally graded materials. in the calculation of the stress intensity factors in isotropic, the order of singularity of stress field in vicinity of the crack is same as isotropic materials [5]. the study of the fracture analysis of fgms were increased in the previous forty years. the major information on these types of materials had been extracted by using the numerical methods rather than the theoretical methods that had inability to analyze the complicated material problems. where, dolbow and gosz [6] presented approach that was applicable to the analysis of any fgm in which the form of the asymptotic near-tip fields match those of a homogeneous material and it does not required detailed knowledge of the higher order terms. in the derivation, an interaction energy contour integral was expressed in domain form and evaluated as a post processing step in the x-fem. rao and rahman [7] used meshless method (efgm) for calculating the fracture parameters of isotropic fgm by developing new two interaction integrals by depending on homogenous and nonhomogenous auxiling field. in addition, kim and paulino [8] developed with using fem as a numerical method, an accurate scheme for evaluating mixed-mode sifs by means of the interaction integral (m-integral) method considering arbitrarily oriented straight and curved cracks in two-dimensional (2d) elastic orthotropic fgms. the interaction integral proved to be an accurate and robust scheme in the numerical examples where various types of material gradation, such as exponential, radial, and hyperbolic-tangent, were considered. they observed that material orthotropy, material gradation and the direction of material gradation may have a significant influence on sifs. dai, et. al. [9] used a meshfree model for the static and dynamic analyses of functionally graded material (fgm) plates based on the radial point interpolation method (pim). in the method, the mid-plane of an fgm plate was represented by a set of distributed nodes while the material properties in its thickness direction were computed analytically to take into account their continuous variations from one surface to another. based on the current material gradient, it was found that as the volume fraction exponent increases, the mechanical characteristics of the fgm plate approach those of the pure metal plate blended in the fgm. also, kim, and paulino [10] provided a critical assessment and comparison of three consistent formulations: non-equilibrium, incompatibility, and constant-constitutive-tensor formulations to use in the calculation of stress intensity factor in fgms. gao, et. al. [11] presented crack analysis in 2d, with continuously inhomogeneous, isotropic al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 and linear elastic fgms. for this purpose, a boundary-domain integral equation formulation was applied. recently, xfem fracture analysis of orthotropic functionally graded materials, with orthotropic crack tip enrichments was used by bayesteh, and mohammadi [12]. it was cleared that the efficiency of the numerical method in crack analysis of isotropic and anisotropic functionally graded materials (fgms). extended finite element method xfem [13-14] is a powerful numerical tool in modeling discontinuity and has been taken into consideration in recent years. xfem is a development of standard finite element method which employs local enrichment of a region using the concept of partition of unity. consequently, xfem is moved beyond the limitations of standard finite element method in numerical simulation of discontinuity and also, it has the general advantages of standard fem. applying heaviside function in xfem, there will be no need to geometric model of crack and as a result, crack propagation problem can be solved without remeshing. standard fem employs the ordinary polynomials in modeling cracks and therefore, it is unable to simulate the nonlinear behavior of crack tip and is resulted in mesh dependency of outcomes. although implementing singular elements is resolved mesh dependency in fem, the exact displacement field at crack tip can be reproduce by xfem and there is no mesh. the type of the element in xefm is very important for depicting of the behavior of the different complex problems. the division into elements may partly correspond to natural subdivisions of the structure [15].proved that higher order element such as triangular element gives more fit result in comparing with the analytical solution. also, the complexity of the material properties (functionally graded materials fgm, or weak /discontinuous problems) of the whole problem needs proper element with higher order to capture the finest traits of the complex materials [16]. to the best knowledge of authors, xfem has not been employed to model crack in fgm media under mechanical. so, the purpose of this paper is to study crack in the complex material as fgm mechanical using xfem with appropriate t3-element. to reach on this goal, formulation of the xfem model is discussed by considering orthotropic enrichment to achieve higher accuracy and less dofs. afterward, changing of the material properties effects on the formulation are represented. also, the sub-triangular technique for numerical integration near the crack tip, effective nodal distribution near crack tip and for the whole geometry, and interaction integral method (m-integral) with the incompatibility form to calculate sif are used to capture more accuracy. numerical example is employed to verify and compare xfem models with previous reference. all the work is verified by developed code using matlab environment. 2. formulation of problem in section, governing equations for fgm fracture analysis including stress-strain relationship, stress and displacement field, extended finite element method and standard finite element approach is discussed and the parameters are explained. 2.1 stressstrain relationship the governing relationship of plane stress-strain in this problem is the form of hook’s low and can be written as [17] (1) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 are total, mechanical and thermal strain, respectively. where (2) and equals zero in this work. in which (3) (4) in the case of plane strain, should be substituted, ( ) → (5) as can be seen in eq. (2), the components of material compliance tensor can be expressed by [ ] [ ] (6) where (7) considering the stress function for an anisotropic case and employing the basic theory of elasticity, the characteristic equation is obtained in the following form (8) it is obvious that the roots of eq. (8) are complex and can be define in the form of conjugate pairs, ̅ ̅ [17], (9) or in the general form of (10) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 2.1. stress and displacement field the displacement and stress field for the problem has been developed [18-19], the obtained asymptotic displacement crack tip can be expressed as √ { [ ]} √ { [ ]} (11) √ { [ ]} √ { [ ]} (12) where ( , )x y are considered the components of global coordinate system,(x, y) the components of the local crack tip system and the local crack tip polar coordinate system (r, θ) can be defined by x+iy=re iθ , which are demonstrated in figure (1). moreover, re implies the real part of complex displacement functions. also, and are defined as the components of displacement in x and y directions, respectively. √ (13) (14) (15) furthermore, the components of asymptotic stress are in the form of √ { [ ]} √ { [ ]} (16) √ { [ ]} √ { [ ]} (17) √ { [ ]} √ { [ ]} (18) in the fgms, the components of material compliance tensor, aij, are changing on the material volume. as a result, there are different amount of pk, qk, and at one point compared to another. for this reason, material properties for the auxiliary field (in contour integral) and crack tip enrichment functions are calculated at the crack tip. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 according to the explanations, the parameter should be replaced with in eqs. (11-18) to modify the equations for the fgm materials. → (19) where is the representation of aij, pk, qk and , and states these parameters at the crack tip. 2. stress intensity factors 2.1. calculating j-integral non-equilibrium, incompatibility, and constant-constitutive-tensor are three different methods have been employed by kim et al [10] for this side. the incompatibility formulation is employed in this paper as the method is used to approximate j-integral for the reseason that this procedure requires less complicated derivatives with the same accuracy of nonequilibrium formulation [10,19]. also, constant-constitutive-tensor method leads to inaccuracy with 0 c finite element formulation. the incompatibility procedure satisfies the following equations ( ) (20) which includes constitutive and equilibrium equations and is the material modulus while it does not satisfy compatibility. inversing the first part of eqs. (20) yields (21) where s=c -1 . on the whole, using the equivalent domain integral (figure (2)), j-integral can be expressed as ∫ ( ) ∫ ( ) (22) where q is a smooth function from q=1 on interior boundary of a and q=0 on the outer one, as depicted in figure (2). and jn is the jth component of the outward unit normal to , is the kronecker delta and the cartesian coordinate system whose axis is parallel to the crack surface. is the strain energy density which can be presented as (23) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 for plane stress and (24) for plane strain. since in the plane strain condition, → (25) eq. 25 is useful if the analyze is done with thermal and mechanical load. 2.2 different parts of stress intensity factors to calculate stress intensity factors of mode i and ii, the interaction integral is applied. can be divided into three components including and (26) in which the auxiliary and actual field j-integral are expressed by , respectively. considering ( ) (27) interaction integral can be expressed as (28) where by some manipulating, can be expressed as ∫ { } ∫ { ( ) } (29) it should be mentioned that there is no thermal effect in auxiliary field and is mechanical strain. also, al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 (30) in the plane stress condition. furthermore (31) in an elastic media, the released energy rate can be expressed as (32) where ( ) (33) ( ) (34) (35) the effect of two superimposed fields can be considered using the expression [20] (36) substituting and into eq. (36), the equation will be simplified in the form of { } (37) and stress intensity factors of actual modes i and ii can be achieved easily. 2.3 a review of extended finite element method the extended finite element method (xfem) is a numerical method has been implemented comprehensively for fracture analysis of various problems in past two decades. xfem is a standard al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 finite element method development which is more appropriate for the problems with discontinuity and singular fields. the partition of unity finite element method pufem can be implemented to create more convergent and effective numerical methods. xfem employed the concept of partition of unity (pu) to reproduce the displacement, strain and stress fields. the minimum requirement for a function k g which can be used in pu is to satisfy the following condition [13] ∑ (38) the definition of reproducing condition or completeness can be considered for an arbitrary function in the domain of eq. (38) and yields, ∑ (39) as the set of isoparametric finite element shape functions ni , satisfy eq. (38), these functions can be employed as local enrichment functions to reproduce the desired fields ∑ (40) where expresses the enriched nodes, are the shape functions and are the additional dofs. considering m collection as the following { } (41) the arrays of m are the enrichment functions. introducing eq. (41) into eq. (40) gives ∑ (∑ ) (42) to accurate the results of the solution, small elements with higher order (t3-triangular elements) are used rather than q4 (quadratic elements) elements of the relevant references. the t3-elements are used for whole domain to control on behaviors of the complex materials such as fgms. employing xfem, the obtained displacement field will be added to the displacement field achieved by standard finite element method in the form of (43) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 344 in which can be expressed (for the element near the crack) as (44) where are the displacement of tip enrichment domain, heaviside enrichment domain and transition domain, respectively. on the whole, discretization of domain geometry in xfem is performed in the same way of the traditional finite element method. ∑ ̂ (45) to describe and to model the crack, level set method is used [13]. in this approach, only nodal data were used to describe the crack; no geometrical entity was introduced for the crack trajectory, and no partial differential equations need to be solved to update the level sets as that needed in conventional fem. where, the nodal description can be updated as the shape function equations. 3. enrichments 3.1 heaviside enrichment for discontinuity the xfem ability in simulating discontinuity is originated from applying heaviside function for enrichment. different types of heaviside function are proposed in the literature, one of these form is { (46) in which to evaluate the amount of , the sign distance function is implemented, as shown in figure (3). for a point x in the heaviside enriched domain, and as the projection of point x on the crack, is defined as (47) in which (48) and the unit normal vector of crack line at is denoted by . considering s as the set of nodes which have the heaviside function enrichment, can be expressed as al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 ∑ ̂ (49) 3.2 enrichments at the crack tip he implementing of enrichment functions at the crack tip leads to reproducing the highly non-linear stress and displacement fields around the crack with higher accuracy. due to the difference between the behavior of these fields near the crack and other areas, the standard finite element shape functions are not able to approximate the fields in both areas with high accuracy. consequently, considering appropriate crack tip enrichments in the elements near the crack tip can improve the obtained results in this area. the enrichments will be determined according to the nature of these fields. considering f as a set of tip enrichments, yields, { } (50) the displacement field at the crack field can be estimated by ∑ (∑ ̂ ) (51) where tip are the enriched nodes using the tip enrichments functions and ̂ are the extra dofs due to the enrichments. the chosen tip enrichments functions for isotropic homogeneous materials can be represented in the form of [21-22]. {√ ( ) √ ( ) √ ( ) √ ( ) } (52) 3.3 obtaining displacement field in xfem introducing heaviside and tip enrichment displacement field in standard finite element method displacement field gives [21-22]. [∑ ̂ ] [∑ ( ) ̂ ] [∑ (∑ ̂ )] (53) where the first expression is corresponding to standard finite element method, heaviside enrichment and tip enrichment. 3.4 enrichment functions for orthotropic materials increasing number of studies on orthotropic materials, more researches are performed in obtaining enrichment functions for these materials. several functions for crack tip enrichment are achieved by the following expression is proposed in the polar local coordinate for crack tip enrichment [21-23]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 {√ ( ) √ √ ( ) √ √ ( ) √ √ ( ) √ } (54) where √( ) ( ) (55) ( ) (56) in which and are the same as eq. (10). 4. numerical integration usually the gauss quadrature rule is employed for numerical integration inside the background cell. generally, four gauss points are used in the standard four-node cell. existence of discontinuity within a background cell may result in substantial accuracy reduction. also, many researchers demonstrated that a regular increase in order of gauss integration does not necessarily improve the integration over a discontinuous element/cell, whereas independent integration of each side of the discontinuity with even low order rules does guarantee an accurate integration [19]. so, an efficient technique is required to define the necessary points needed for the integration within these background cells, while remains consistent with the crack geometry. an approach similar to the one proposed by [24] and originally utilized by [19] is adopted for the first time for fracture analysis of fgms by efgm. any background cell which intersects with a crack is subdivided at both sides into sub-triangles whose edges are adapted to the crack faces, as illustrated in figure (2). it is important to note that, while triangulation of the crack tip element substantially improves the accuracy of integration by increasing the order of gauss quadrature, it also avoids numerical complications of singular fields at the crack tip because none of the gauss points are placed on the position of the crack tip. 5. numerical case study proper case study is presented in this section to illustrate the application of the xefm with t3-element for crack analysis of functionally graded materials (fgms). to accurate the results of the solution, small elements with higher order (t3-triangular elements) are used for the whole problem. the t3elements are used for whole domain to control on behaviors of the complex material properties such as in the behavior of fgms. matlab program (m-file) is used to illustrate the aim of this paper. the sub-triangular technique near the crack tip (13 gauss point at crack tip and with crack surface, and 7 gauss points for others), the proper nodal distribution for local crack region and for the whole geometry, and the interaction integral method with the incompatibility formulation to calculate sifs are used the crack analysis in fgm. the level set method is used to represent the crack. therefore, a square plate with a center crack is presented (l/w=1), as shown in fig. 5. a center crack of length 2a located in a finite two-dimensional plate under fixed grip loading, the complete finite element mesh, a mesh detail with mesh type t3, and a zoom of the crack tip region, are depicted in al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 343 figure (6) and (7) respectively. for fixed-grip loading, the applied load results in uniform strain for a corresponding uncracked plate. the variations of e11, e22,and g12 are assumed to be an exponential function of x1 and proportional to one another, while the poisson's ratio is constant ( . the xfem mesh has 3042 t3, with 1600 nodes as shown in figure (6) for mesh distribution, where the nodes are applied on the edges of elements to be following the rules of background technique that explain well in [17, 20]. comparison well be made with [25] that used mesh 1666 q8, 303 t6, and 32t6qp crack-tip singular finite elements with a total of 2001 elements and 5851 nodes. firstly, the present work will be less time cost where dofs less than that used in reference [25]. the following data were used for the xfem analysis: , , it can be observed from table (1) that the good agreement of the normalized sif of the present work in comparison with the reference value under the changing of material non-homogeneity of functionally graded material. where six statues of the material properties changing is taken as explain in table (1). to further verification of present work on the solution accuracy and the stability of t3-element using with other useful applied techniques, figure (8) clearly shows that no sensitivity (very small change) is occurred at the change of the radius of j integral/a (0.2-1) with the value of the normalized stress intensity factor. so, from table (1) and figure (8), one can show the stability and good agreement of the present work with less dofs in comparing with the relevant reference. incompatible m-integral method is used to calculate the stress intensity factors as explain in section 2. the problem that studied and presented is done by developing a matlab code. all items of the xfem and the applied-fracture mechanics lefm are presented completely. so in the programming package, any geometry preprocessing and post-processing with any boundary conditions and substations, and other advanced problems can be easily depicted and studied. 6. conclusion the development of this work for isotropic and fgms crack analysis by xefm that uses of the t3element, sub-triangle technique for the numerical integration, with proper enrichment 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"on enrichment functions in the extended finite element method", international journal for numerical methods in engineering, wiley-blackwell, 2012, 91 (2), pp.186-217. [17] lekhnitskii, s.g., "theory of an anisotropic elastic body", mir -publisher, moscw, 1981. [18] sih, g.c., paris, p.c., irwin, g.r., on cracks in rectilinearly anisotropic bodies. international journal of fracture mechanics, 1965: p. 189-203. [19] s.s. hosseini, h. bayesteh, s. mohammadi, "thermo-mechanical xfem crack propagation analysis of functionally graded materials", materials science & engineering a 561 (2013) 285– 302 [20] wang, s.s., yau, j.f., corten, h.t. , "a mixed mode crack analysis of rectilinear anisotropic solids using conservation laws of elasticity". international journal of fracture, 1980. 16: p. 247259. [21] soheil mohammadi, " extended finite element method for fracture analysis of structures " first published 2008 by blackwell publishing ltd. [22] soheil mohammadi, " xfem fracture analysis of composites" first published 2012 by 2012 john wiley & sons, ltd. [23] a. asadpoure, and s. mohammadi, “developing new enrichment functions for crack simulation in orthotropic media by the extended finite element method” int. j. numer. meth. engng 2007; 69:2150–2172 [24] j. dolbow “an extended finite element method with discontinuous enrichment for applied mechanics”, theor appl mech, ph.d. thesis. northwestern university, evanston, il, usa, 1999. [25] j.-h. kim, and g. h. paulino, “the interaction integral for fracture of orthotropic functionally graded materials: evaluation of stress intensity factors” international journal of solids and structures 40 (2003) 3967–4001. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 table (1): the effecting of material non-homogeneity on normalized mode i sif in a nonhomogeneous orthotropic plate under fixed grip loading ki(-a)/k0 (present) ki(-a)/k0 [25] m integral ki(-a)/k0 [25] mcc 0.00 0.9958 0.9969 0.9986 0.10 0.9267 0.9247 0.9251 0.25 0.8307 0.8245 0.8233 0.50 0.6717 0.6706 0.6680 0.75 0.5341 0.5404 0.5358 1.00 0.4250 0.4335 0.4285 figure (1): crack tip geometry e2(x1,x2) e1(x1,x2) x1 x2 r θ α x1 x2 t al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 figure (2): equivalent domain integral figure (3): sign distance function parameters [19] x1 x2 x2 x1 θ r crack q=1 q=0 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 (a) (b) figure (4): gauss points around the crack: (a) sub-triangles technique and (b) conventional (ordinary) distribution [21] figure (5): complex fg plate with a crack parallel to material gradation. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 333 figure (6): structured mesh of whole domain; the crack is modeled by level set method figure (7): zoom for crack region al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 334 figure (8): the verification of the present work that occurred between the radius of j integral and normalized sif article al-qadisiyah journal for engineering sciences 12 (2019) 112–117 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: shahadmahdi2015@gmail.com (shahad al-obaidi) https://doi.org/10.30772/qjes.v12i2.599 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. improve the octane number of gasoline and studying the effect of reid vapor pressure and calorific value by using environmental additives shahad al-obaidia* and husham al-tameemi a a faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 16 june 2019 received in revised form 15 july 2019 accepted 16 july 2019 keywords: octane number reid vapor pressure calorific value di-isopropyl ether olive oil aniline a b s t r a c t an assessment was made for the impact resulted by the addition of (mixing of di-isopropyl ether with olive oil (do)) and (mixing of di-isopropyl ether ,olive oil and aniline (doa)) on the octane number as well as reid vapor pressure (rvp) of gasoline with different chemical compositions. the locally produced gasoline is blended with three different ratios (v/v) of the additives, i.e. 8, 10 and 15%. it was observed that the octane rate of gasoline increased continuously and linearly with the addition of (mixing of di-isopropyl ether and olive oil (do)) and (mixing of di-isopropyl ether ,olive oil and aniline (doa)). the doagasoline blends produced higher gasoline octane number. the two additives noted a significant reduction in rvp and cv of the original fractions when blended with gasoline. however, additives were add in (8, 10, 15%vol) to gasoline blend, increasing ron was (0.9-23.9). © 2019 university of al-qadisiyah. all rights reserved. 1. introduction gasoline, also called petrol or gas, is defined as a combination of volatile, flammable liquid hydrocarbons, derived from petroleum and used to internal combustion engines as fuel. another use of it as a solvent for fats and oils, originally a byproduct for petroleum industry (kerosene being the main product), gasoline became the favorite vehicle fuel because of its ability to mix readily with air in a carburetor and high energy of combustion [1]. gasoline, like other hydrocarbons, does not ignite in its liquid state, as it must first evaporate and mix with oxygen to ignite [2]. where it is derived from oil, it is also the most popular producer and forms the bulk of the product which got per barrel of crude oil [3]. the composition of gasoline (% volume) varies widely depending on refining processes and the crude oil used and the overall balance of demand for products [4]. the typical structure of hydrocarbons in gasoline is shown in table 1. octane number is defined as one of the most paramount characteristics of gasoline currents and is a measure of its knock resistance property. another definition is the percentage of the volume of i-octane in a blend of i-octane and n-heptane, which produces the same knock incisiveness caused by the fuel test under standard test circumstances in an (astm) internal combustion engine. the astm defined various kinds of octane number: motor octane number (mon) and research octane number (ron), which are an assessment by using astm tests d2700 for (mon) and astm d2699 for (ron) [5]. the self-ignition of fuel causes a knocking impact in gasoline engines. knocking is a severe, pinging sound due to the combustion of the air-fuel mixture in the cylinder, it increases the risk of engine damage and reduces engine efficiency. spark-ignition engines have been modeled to burn gasoline in a controlled process termed deflagration, http://qu.edu.iq/ https://doi.org/10.30772/qjes.v00i0 shahad al-obaidia and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 112–117 113 nomenclature add. additive mtbe methyl tert-bbutyl ether aki. antiknock index nox nitrogen oxides astm american society for testing material on octane number cv calorific value ref. reformate dipe di-isopropyl ether rvp reid vapor pressure do mixture of ( di-isopropyl ether +olive oil) ron cooperative fuel research doa mixture of ( di-isopropyl ether +olive oil + aniline) sp.gr specific gravity edb ethylene dibromide sln sweet light naphtha h.n heavy naphtha tel tetraethyl lead l.n light naphtha us united states lsrn light straight run naphtha usepa us public health service mon motor octane number vol. volume where this process is significant in the timing of combustion, which could negatively be affected by the self-ignition of gasoline and result from the phenomenon commonly indicated as the engine knock [6, 7]. generally, octane number increases with increasing the chain of branching and aromatics of carbon molecules and decreases with the chain length of carbon molecules. straight chain alkanes like octane, heptane, and nonane ignite very easily and burst very soon , branching chain alkanes like (2,2, 4-tri methyl pentanes) iso-octane do not tend to self-ignite and cyclic compounds contain octane number higher of compounds of the straight chain [8, 9]. in the early twentieth century, motor engineers found out that engines without knock will work more efficiently and smoothly. thomas midgley a research scientist at the dayton research laboratories in dayton, ohio, has found in 1916 that adding iodine to gasoline has significantly decreased motor knocks. a joint research work between midgley and charles kettering (inventor of the electric self-start device) was conducted in 1917, where they mixed ethyl alcohol (grain alcohol ) with gasoline and they concluded that such alcohol blended with gasoline could produce suitable fuel for cars. in december 1921 midgley found out anti-knocks characteristics of tetraethyl lead (tel). in 1923 tel began manufacturing with a petite operation in dayton, ohio which produced nearly 600 l of the tel per day [10]. us public health service (usphs) mentioned that each liter of burning gasoline would emit 1 gram of lead oxide that would accumulate at a grave level along the heavily traveled roads. in early 1970s past century briefly, (edb) ethylene dibromide has been added to leaded gasoline to decrease the harmful impact of lead on vehicle engines. a new use is found by edb manufacturers of this chemical as a pesticide because of the outlaws. prohibition of the use of gasoline that contains lead of highway cars in the united states as of 1 january 1996 [11]. the oxygenates has been widely used in gasoline until 1979, when methyl tert-butyl ether (mtbe) has been added to gasoline to replace (tel) and increases the fuel octane rate. through intensive negotiations among the oil industry representatives, cars and usepa, state officials, gasoline retailers, environmental organizations, oxygen suppliers, and consumer groups and as a portion for the clean air act amendments of 1990 [12]. at present, ethanol becomes a substantial portion of the alternative fuel market particularly in brazil, usa, australia and sweden and other countries [13]. ethanol and ethanol-gasoline mixtures are burned cleanly and contain greater levels of octane than pure gasoline, and there results less carbon monoxide and unburned hydrocarbon. carbon monoxide represents a direct threat to human health ,also precursor ozone. ethanol fuel contains a high temperature of evaporation, which decreases the temperature inside the cylinder, reduces nox emissions and increases engine power. on the other hand, it has greater evaporative emissions from distribution equipment and fuel tanks. the emissions of evaporative contribute to the formation of smog and ozone at ground level [14]. in general, the impact of ethanol on nox and co emissions is minimal in newer engine emission control systems [15]. as it's known several chemical additives have been used to improve the octane number of gasoline, but the using of natural substances in mixed with chemicals as additives has not been tried so far. the aim of using these additives is to improve the internal combustion engines octane number and decrease air pollution. table 1. typical structure of hydrocarbons in gasoline ( % volume) the typical structure of hydrocarbons in gasoline % volume alkanes 4-8 alkenes 2-5 benzene 0.5-2.5 cycloalkanes 3-7 cycloalkenes l-4 isoalkanes 25-40 total aromatics 20-50 2. materials and experimental procedure 2.1. materials 1gasoline (ref. and sln) reformate and sweet light naphtha are obtained from al-daura refinery in iraq . 2dipe and aniline of 99.95% purity are of analytical reagent grade and are obtained from sigma company. 3olive oil is obtained from local markets. 2.2. experimental procedure 2.2.1. first stage preparation of gasoline pool and additives. the gasoline pool contains 50%vol of ref. and 50%vol of lsrn. the preparation of additives include 114 shahad al-obaidia and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 112–117 mixing of (95% dipe and 5% olive oil) and mixing of (30% dipe ,2% olive oil and 68% aniline) are as follow: 17 l of gasoline pool are blended in a bowl had fitting cover with stirring using the rod at refrigerator temperature (5°c), for reduce fumigation of the volatile components. 2400 ml of the first additive are blended in a bowl had fitting cover with stirring using the rod at refrigerator temperature (5°c) . 3400 ml for the second additive are blended in a bowl had fitting cover with stirring using the rod at refrigerator temperature (5°c). 2.2.2. second stage the prepared additives are used at various volume percentages. all the prepared additives are tested during the preparation of the gasoline pool of the blends as follows: 1reid vapor pressure (rvp) and octane number (on) of gasoline pool are measured by rvp measurement and cfr engine before adding the compounds (the additives). 2three glass containers are filled with (92%, 90%, 85%) of gasoline pool and added (do) in different concentrations (8% ,10%, and 15%) with shaking by using a rod. 3the reid vapor pressure and octane number for these blends are measured by apparatus reid vapor pressure measurement and cfr engine. 4repeat steps 2 and 3 above with (doa) additives. table 2. laboratory testing of al-daura refinery petroleum cuts sample l.n feed bottom h.n reformate sp.gr 83.5 64.5 64.9 60.4 52.5 rvp 17.3 6.6 distillation i.b.p 32 48 54 82 44 5% 36 56 62 92 60 10% 40 66 70 98 72 20% 46 74 78 104 82 30% 54 86 89 110 94 40% 62 98 102 116 106 50% 68 108 114 124 116 60% 76 116 122 132 126 70% 84 124 128 140 134 80% 90 132 136 144 144 90% 94 144 146 148 152 95% 98 152 154 158 162 e.p 120 174 176 180 190 ron 62 90 2.3. analysis method the fuel properties of the blends tested are determined in accordance with the american standard for testing materials (astm) procedures of the petroleum products. 2.3.1. cooperative fuel research engines (cfr) (d2699) is used to determine the octane number as follows: aa standard test engine and operating conditions are used to determine the research octane number ron of a spark-ignition engine fuel to compare its knock properties by those of prf blends of known ron. to produce a standard aki for specimen fuel, the ratio of fuel to air is regulated, as measured by means of a specific electronic detonator instrument meter system. to maximize the aki for each fuel, the fuel-toair ratio of the fuel specimen and each mix of the fundamental reference fuel blends is regulated. bthe fuel-air ratio can be gotten for maximum aki through: 1note the aki equilibrium value for each step by making gradual changes in the power of the mixture, and then select the conditions that increase the reading. 2the power of the mixture is changed from either rich to lean or lean to rich at a fixed rate and so via selecting the maximum of aki. the device is shown in fig. 1. figure 1. show research method test engine 2.3.2. standard test method of the vapor pressure for products petroleum (reid method) (d323) is used to determine the reid vapor pressure as follows: ahow to prepare the sample for testing: the bottle is filled with 80% of its size and then closed, placed in a water bath until it reaches (0°c) and then open and return to the water bath and repeat this process 3 times. bmethod of examination: fill the form into the product and close it tightly and place it inside the tub, check by pressing the test button. the reading is taken from the screen corresponding to the same number for the chamber after it is constant. the device is shown in fig. 2. figure 2. reid vapor pressure test engine shahad al-obaidia and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 112–117 115 3. results and discussions in this study, olive oil (5 and 2 vol.%) are selected and mixed with other additives. the gasoline combustion engine, in this case, leads in both an increase in fuel mileage and reducing harmful emissions. the addition of olive oil to gasoline will improve combustion efficiency and thus reduce co2 emissions, while the addition of dipe (oxygenate compound) increases co2 because of the complete combustion and decrease co. this may be due to smaller combustion produces an increase in oxygenate content when dipe increases in the blends. the smaller combustion reduces carbon monoxide emissions in the exhaust gas. this means that the addition of olive oil with dipe to gasoline is to reduce the co2 that increases with the addition of dipe alone to gasoline [16, 17]. the following study effectiveness of (do and doa) on the octane number, reid vapor pressure, and calorific value. 3.1. research octane number (ron) one of the expected tests for appraisal the octane number, as characterized in astm d2699, research octane number, using a single drum engine running at 600 rpm. results of the ron tests shown in table 3. for the addition (do and doa) to gasoline pool. table 3. results of ron when blending (do, doa) with gasoline pool ron of (doa) blend number ron of (do) blend number blending ratio 100% asoline + 0% add. 1 76 1 76 92% gasoline + 8% add. 2 76.9 5 99.5 90% gasoline + 10% add. 3 77.5 6 97.5 85% gasoline + 15% add. 4 79.2 7 99.6 the ron values of tested gasoline blends with (do) started with 8% of (do) and 92% of gasoline pool (shown in fig. 3.), it was found that the octane rating was continuously and linearly increased with a range of 0.8 of blending ratio but the increase will be slightly also when increasing the proportion of additives up to 15% give ron equal to 79.2. figure 3. ron value of the gasoline with the ratio of (do) additive the increasing of the (doa) until 15 % of the blending samples increase ron number slightly reaching to 99.6 and this increase is due to the presence of aniline with olive oil and di-isopropyl ether, where aniline is characterized as an aromatics, which are characterized by the high fuel source of energy and high octane levels, and thus are able to achieve target values to the octane quality [18] but at 10% decrease to 97.5 due to a malfunction of the device when reading . the readings are shown in fig. 4. figure 4. ron values of the gasoline along with the ratios of (doa) additives 3.2. reid vapor pressure the results of the vapor pressure measured in psi unit at 37.8 °c (rvp) of the original gasoline compositions and the ones structures with different percentages of compounds (additives) are presented in table 4. table 4. results of rvp when blending (do, doa) with gasoline pool ron of (doa) blend number ron of (do) blend number blending ratio 100% gasoline + 0% add. 1 9.7 1 9.7 92% gasoline + 8% add. 2 8.01 5 8.4 90% gasoline + 10% add. 3 7.4 6 7 85% gasoline + 15% add. 4 7.15 7 6.5 the rvp values of tested gasoline blends with (do) significantly reduce the reid vapor pressure to 7.15 as shown in fig. 5. figure 5. rvp values of the gasoline with ratios of (do) additive and with (doa) decreasing the rvp to 6.5 as shown in fig. 6. this decrease in rvp when adding di-isopropyl ether to gasoline is due to its high molecular weight and has low fluctuations. similarly, the addition of olive oil also reduced rvp due to its high density [19]. 116 shahad al-obaidia and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 112–117 figure 6. rvp values of the gasoline with the ratios of (doa) additives 3.3. calorific value the results of the calorific value in kcal/kg (shown in table 5. ) is calculated theoretically depending on the bellow equation : calorific value (cv) = [12400(2100(sp.gr.)2)] [20]. table 5. results of rvp when blending (do, doa) with gasoline pool ron of (doa) blend number ron of (do) blend number blending ratio 100% gasoline + 0% add. 1 ..153112 1 11350.32 92% gasoline + 8% add. 2 11345.09 5 11295.70 90% gasoline + 10% add. 3 11343.77 6 11281.83 85% gasoline + 15% add. 4 11340.50 7 11246.77 the specific gravity of the gasoline and additives is determined using the values of the densities of the samples obtained by the astm (d287) method. the cv values of tested gasoline blends with (do) that significantly reduce the calorific value from 11350.32 to 11340.50 as shown in fig. 7. and with (doa) decreasing the cv to 11246.77 as shown in fig. 8. figure 7. cv values of the gasoline with ratios of (do) additive figure 8. cv values of the gasoline with ratios of (doa) additive however the effect of additional olive oil with aniline has enhanced the octane number of the blending gasoline due to carbon bonds in the aniline compound tend to give an addition reactions of free oxygen radical or h free radical, oh free radical or ho2 radicals [21]. the disadvantage of using aniline alone as gasoline additive is considered as carcinogenic and courses hemolysis additive [22], but blending aniline with olive oil ( which can be considered as green oil ), in addition it has a high octane number and (dipe) can decrease the harmful and carcinogenic emissions as a result of decreasing the aniline ratio in the blending samples as shown table 6. table 6. aniline ratios used in (doa) additive in the total blending sample ratio ron of (doa) blend number 100% gasoline + 0% doa 0 92% gasoline + 8% doa 5.44 90% gasoline + 10% doa 6.8 85% gasoline + 15% doa 10.2 4. conclusions depending on the analytics discussed earlier, conclusions can be drawn in the following: the prepared component mixtures act positively to improved the octane number. • by looking at the results shown in the figures, the increase in the octane number was obtained with doa more than with the presence of do, indicating a clear effect of the aniline on the increase. • (doa) is the best prepared component mixtures for improve octane number where it rises octane number from 76 to 99.5 at concentration 8%. • the preparation component mixtures reduce the rvp. • rvp for gasoline after all additions with various concentrations were found within the limits assigned by astm. • the effect of adding olive oil is clear by reducing the reid vapor pressure because of its high density. • the calorific value of (doa) is decreased that means we can get an additive that gives a characteristic similar to the fuel or better. • the advantage of the using aniline as a gasoline additive in the mixture of (doa) instead of pure aniline is : (decreasing harmful emission on the environment) and represent an environmentally friendly additive. shahad al-obaidia and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 112–117 117 references 1. ezeldin, m. and a. massad, quality improvement of sudanese gasoline by using di isopropyl ether and moringa oil. european academic research, 2015. 3(3): p. 2748-2763. 2. leffler, w.l., petroleum refining in nontechnical language. 2008: pennwell books. 3. demirbas, a., et al., octane rating of gasoline and octane booster additives. petroleum science and technology, 2015. 33(11): p. 1190-1197. 4. harper, c. and j.j. liccione, toxicological profile for gasoline. 1995. 5. seddon, d., octane enhancing petrol additives/products: literature review and analysis. victoria, 2000. 3930. 6. balaban, a., l. kier, and n. joshi, structure-property analysis of octane numbers for hydrocarbons (alkanes, cycloalkanes, alkenes). match commun. math. comput. chem, 1992. 28: p. 13-27. 7. rothamer, d.a. and j.h. jennings, study of the 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technology. 21. boot, m.d., et al., impact of fuel molecular structure on auto-ignition behavior–design rules for future high performance gasolines. progress in energy and combustion science, 2017. 60: p. 1-25. 22. yokel, r.a. and j.s. crossgrove, manganese toxicokinetics at the blood-brain barrier. 2004. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 374 numerical analysis of mixed convection flow and heat transfer in a lid-driven octagonal cavity with heating on two sidewalls mushtaq f. al-mensorey department of mechanical engineering, college of engineering, university of al-qadissiya, iraq. email: mushtaq.almensory@gmail.com received 9 september 2015 accepted 21 september 2015 abstract this paper numerically investigates laminar mixed convection flow through an octagonal cavity enclosure where four cases with different positions and directions of its lid-driven were simulated. the lid-driven moves in horizontal rightward and leftward on its upper wall in the first and second cases while it moves vertical upward and downward on its right side wall in the others cases. the numerical study was carried out by solving the governing equations (continuity, momentum and energy), and applying the tri-diagonal matrix algorithm (tdma) method via ansys 11.0 program. four of the eight external walls of the octagonal cavity enclosure are insulation walls and the other four walls were classified into two hot and two cold walls. the mixed convection flow and heat transfer characteristics through isotherms, streamlines and the average nusselt number were considered based on different richardson numbers (ri = 0.01, 1, and 10). the results demonstrated that heat transfer mechanism, the flow pattern and formation of vortices are significantly dependent on values of the richardson number. within the enclosure, the lid-driven movements showed an improvement in the heat transfer rate where the direction of the sliding wall considerably affected the flow and temperature distributions for all values of the richardson number. the nusselt number of the lid-driven increased from 50 with the upward motion to 55 (10 % increase rate) with the downward motion counterpart, and increased from 12 to 17 (40 % increase rate) with the rightward and the leftward motions, respectively. keywords: mixed convection, octagonal cavity, lid-driven, tri-diagonal matrix algorithm (tdma). المختلط في تجويف ثماني ذو غطاء متحرك والجريان التحليل العددي للحمل الحراري وحرارة من جانبين م.م. مشتاق فيصل المنصوري الخالصة: محاكاة أربع تتمحيث , الشكل ثماني خالل تجويف المختلطوالجريان الحراري للحمل عدديا البحث, تم انجاز التحليل الهذفي لجدار لنحو اليمين ونحو اليسار االت االربعة تتمثل بحركتين افقيتين الحالمتحرك. طاء ذات مواقع واتجاهات مختلفة للغحاالت أجريت الدراسة العددية من خالل حل للغطاء المتحرك. األيمن للجدار صعودا وهبوطا وحركتين عموديتين غطاء للالعلوي برنامج باستخدام ( tdma)قطار ذات الثالث اخوارزمية الوالطاقة( وتطبيق طريقة ،المعادالت الحاكمة )االستمرارية، الزخم ansys 11.0 جداران لة والجدران األربعة األخرى هموزمعجدران م هالمثمن ثمان جدران الخارجية للتجويف ال. أربعة من مخططات الحرارة و خطوط على مختلط وخصائص انتقال الحرارة التدفق الحراري التأثير تمد واعساخنان واخران باردان. mailto:mushtaq.almensory@gmail.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 373 انتقال (. أظهرت النتائج أن آلية ri=0.01, 1, and 10ريتشاردسون )لعلى أرقام مختلفة أعدد نسلت بناءومعدل الجريان معدل حسنت غطاء وان حركة ال دد ريتشاردسونعتدفق فضال عن تشكيل الدوامات تعتمد بشكل كبير على قيم الالحرارة ونمط لجميع التجويف بشكل كبير على تدفق وتوزيع درجات الحرارة داخل ؤثر المنزلق )المتحرك( ي الجداروان اتجاه انتقال الحرارة الحركة مع 00الى االعلى الحركة العمودية باتجاه%( مع 05)معدل زيادة 05عدد نسلت ازداد من أنريتشاردسون، اعداد .باتجاه اليسار 07 اليمين الىة االفقية باتجاه الحرك%( مع 35)معدل زيادة 01من سفل واألباتجاه العمودية nomenclature: symbol description unit symbol description (greek symbols) unit cp specific heat j/kg. o c  thermal diffusivity m 2 /s g gravitational acceleration m/s 2  volumetric coefficient of thermal expansion k -1 hf film coefficient μ viscosity n.s/m 2 k thermal conductivity of fluid w/m. °c  kinematic viscosity of the fluid m 2 /s l side length m ρ density of the fluid kg/m 3 nu average nusselt number ψ stream function m 2 /s p pressure n/m 2 {η} unit out ward normal vector pr prandtl number, pr= /   thermal diffusivity m 2 /s q heat flux watt  volumetric coefficient of thermal expansion k -1 {q} heat flux vector μ viscosity n.s/m 2 ri richardson number  kinematic viscosity of the fluid m 2 /s t temperature °c bulk temperature of the adjacent fluid °c ts temperature of the surface of the model °c vx velocity component in x-direction m/s vy velocity component in y-direction m/s x cartesian coordinate in horizontal direction m y cartesian coordinate in vertical direction m introduction the flow and heat transfer of a lid-driven enclosure have taken a considerable interest in the recent years due to their uses in the industrial and thermal instruments such as solar collector, heat exchangers, and cooling of electronic devices [1]. also, the combined mixed convection flow and heat transfer find its applications in float glass production, material processing, crystal growth, metal coating and casting [2]. in order to extensively understand the thermal performance and heat transfer of the mixed convection flow in a lid-driven enclosure, numerous modeling and simulation al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 370 studies considering both the buoyancy force and the shear force caused by the wall motion of the cavity have been published in the literature. for example, sivasankaran et al. [3] numerically investigated the mixed convection flow in a square cavity with temperature on both vertical sides. they found that the non-uniform heating on one wall gave lower heat transfer rate than that for heating on both walls. cheng and liu [2] also investigated the effect of horizontal and vertical temperature gradients on the flow and heat transfer behavior of mixed convection in a square cavity for different richardson numbers. the laminar mixed convection flow in a square cavity with variations of the average nusselt number was numerically simulated using ansys fluent commercial cfd code by akand et al. [4]. it was noticed that the nusselt number does not clearly vary with increasing richardson number till it approaches the value of 1 with which the average nusselt number rapidly increased. furthermore, several numerical studies such as ghasemi and aminossadati [5] and ching et al. [6] indicated the heat transfer and fluid flow of mixed convection in a lid-driven triangle enclosure. they found that the thermal performance of a triangle enclosure filled with water strongly affected with the pertinent parameters i.e., direction of the vertical sliding wall, richardson number and solid volume fraction. the effects of inclination angle and richardson number as well as aspect ratio on the heat transfer in a air-filled square cavity were numerically simulated by cheng and liu [7], and on heat transfer in a rectangular inclined channel by marroquin et al. [8]. the heat transfer in an inclined lid-driven enclosure with different magnetic field angles was investigated by mondal and sibanda [9]. the simulation results showed that the increase of inclination angle does not affect the flow and heat transfer when the flow is in a forced convection dominated regime (ri = 0.01). nevertheless, the laminar mixed convection flow and heat transfer inside an octagonal lid-driven enclosure has not been studied yet. thus, this investigation attempts to address the effects of several pertinent parameters such as the horizontal and vertical sliding wall motions, richardson number and the position of lid-driven whether right or top side on the thermal performance and heat transfer of the octagonal cavity. the numerical analysis was done based on solving the governing equations (continuity, momentum and energy equations) and using the tri-diagonal matrix algorithm (tdma) method via ansys 11.0 program. model description and equations an octagonal cavity shape with four insulated walls, two hot and two cold walls as schematically shown in figure 1 was used in this study. the right and left walls of the octagonal cavity are adopted as hot walls with th, and the top and bottom walls are adopted as cold walls with tc. based on the position and the direction of the lid-driven, four different cases were considered in the analysis (see figure 1). the case 1 adopts the horizontal top lid-driven, moving towards the right hand side; the case 2 is the same as the case 1 expect that its lid-driven is moving towards the left hand side. the case 3 considers the vertical right hand side of the lid-driven, moving upwards, and the case 4 is similar to case 3 expect that its lid-driven is moving downwards. the working fluid used in the cavity is air with pr=0.71 and constant properties. the two-dimensional governing equations (continuity, the momentum and energy equations) [3] based on a steady state one phase and laminar incompressible buoyancy-induced flow were solved by using the commercial ansys 11.0 program as follows: http://www.sciencedirect.com/science/article/pii/s0017931015007486 http://www.sciencedirect.com/science/article/pii/s0017931015007486 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 374 continuity equation [3]:     0      y v x v yx  (1) momentum equations [3]:                                           y x v yx x v x g x v y v x v x v   xx p yx (2)                                               y y v yx y v y g y y v y v x y v x v   xy p (3) energy equation [3]:                                     y t k yx t k x t p c y v y t p c x v  x (4) where vx and vy are the velocity components in the x and y direction, respectively; p is the pressure and t is the temperature. the boundary conditions applied to the computational model are assumed as follows: (i) velocity vx =vy = 0 at all constant walls except that of the moved wall (lid-driven). the variables u and –u refer to velocities of the horizontal lid-driven rightward and leftward directions, respectively. the variables v and –v refer to velocities of the vertical lid-driven upward and downward directions, respectively. (ii) temperature t=th is assumed for all vertical right and left walls, and t=tc is assumed for all horizontal top and bottom walls. (iii) stream function stream function for two-dimensional structure is computed based on the following equation [3]: y v     and xv     (5) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 377 local nusselt number is chosen as an indicator for the heat transfer rate for the purpose of determining the effect of several parameters on the heat transfer. the local nusselt number is defined as: (6) , and the (hf) is obtained from the following equation (7) richardson number (ri) is dimensionless which can be obtained from: (8) where 3. numerical solution over the computational domain, the grid system was done by unstructured quadratic elements, four nodes which are unevenly distributed close to edge of the octagonal cavity enclosure where higher grid densities are desired as shown in fig. 2. the four nodes quadric elements of 43200 were chosen for their more accurate results and low error tolerance. the governing equations are solved with the convergence iteration of 10 -8 for each variable, and integrated over the domain with use of the exponential interpolation in the mean flow direction inside the finite element. using the finite element ansys 11.0 program and employing the tri-diagonal matrix algorithm (tdma), the governing differential equations (continuity, momentum and energy equations) were solved. the theory of tdma algorithm is based on dividing the problem into a series of tri-diagonal problems. for a completely unstructured mesh, or an arbitrary numbered system, the tdma method reduces k lh nu f l        bsf t tthq  2 re gr ri    ul and lttg gr ch    re, )( 3 insulation walls insulation walls insulation walls insulation walls insulation walls insulation walls g tc tc th th case 4 g tc tc th th case 1 u g tc tc th th case 2 u g tc tc th th case 3 v v figure (1): physical model and boundary conditions for four cases. lid-driven lid-driven lid-driven lid-driven al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 374 to the gauss-seidle iterative method and set of algebraic equations is solved based on the successive under relaxation (sur) technique where the 0.1 is taken as an under relaxation parameter. further details about the tdma method can be found in patanker [10]. the grid independence test is normally applied to ensure the accuracy of the numerical results and determine the approach grid density. in comparison of the average nusselt number with number of nodes, the average nusselt number determined by the eq. 6 is constant when number of nodes reached the 50,000 and higher as shown in fig. 3. figure (2): a distinctive grid distribution with quadratic elements. 52.84 52.85 52.86 52.87 52.88 52.89 52.90 52.91 52.92 52.93 0 10000 20000 30000 40000 50000 60000 figure (3): relationship between the average nusselt number and number of nodes. n u number of nodes al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 374 results and discussion results of the effects of horizontal and vertical sliding wall motion and the position of lid-driven with three richardson numbers (ri =0.01, 1, and 10) based on magnitudes of the velocity of liddriven on the streamline, temperature and velocity distribution as well as nusselt number inside the octagonal enclosure are presented in the following sections. 1 top horizontal rightward motion of the lid-driven (case 1). 1.1 flow field (streamline) figure 4a shows the behavior of vortex of the flow field (flow pattern) for ri = 0.01 that gives high velocity when applying the eq. 8. it can be noticed that a single vortex generated inside the cavity due to the high velocity of lid-driven that resulted in frictional losses and stagnation pressure [2]. the direction of horizontal rightward motion of the lid-driven which moves tangentially with the vortex causing in a clockwise recirculation of the vortex. it can be also observed that the minimum value of the vortex is at the middle of the cavity, and the maximum value of the vortex is near the walls. the region of the fluid streamfunctions near the top moved lid-driven wall is almost smaller than this near the others walls. this behavior is attributed again to the effect of the high velocity of the lid-driven [11]. as ri is increased to 1.0 (fig. 4b), the effect of lid-driven on the flow pattern becomes less stronger and the velocity is slower than that of ri=0.01. however, the mechanicallydriven top lid resulted in the generation of two top and bottom vortices inside the cavity plays an important role in increasing the heat transfer rates. these two vortices are approximately in equal size and generated due to presence of free convection and its role that has become nearly equilibrium with the role of force convection. muthtamilselvan and doh [12] found that richardson number strongly affect the fluid flow and heat transfer in the cavity and the forced convection becomes dominant in the entire cavity. the top vortex moves in clockwise direction due to the effect of lid-driven motion and the effect of hot wall on the left side whereas the bottom vortex moves in counterclockwise due to the role of free convection resulted from the hot wall on the right side. when ri is further increased to 10 (fig. 4c), the effect of the lid-driven motion is also caused in generating two top and bottom vortices but they are in different sizes and rotate in different directions. 1.2 isothermal field (temperature distribution) the effect of top horizontal rightward motion of the mechanically-driven lid (case 1) on the isotherm patterns (temperature distribution) for ri = 0.01, 1, and 10 is shown in fig. 4 d-f. in term of ri = 0.01 (fig. 4d), the thermal boundary layer was observed on the hot right and left walls with a small thickness at the top part of the hot right wall. this thickness increased gradually to reach the maximum at the bottom of the same wall. at the hot left wall, the thickness of thermal boundary layer is small at the bottom part of the wall and it increased gradually at the top side of the wall. this is mainly due to the effect of moving air velocity that resulted from the high velocity of the lid-driven which, in turn controls the heat transfer from the hot walls to inside the cavity. with increasing ri to 1 (fig. 4e), the thickness of the thermal boundary layer on the hot wall and the free convection is also increased, leading to maintain a nearly equilibrium between free convection and force convection due to the reduction of the lid-driven velocity. further increasing of ri into 10, the temperature distribution becomes more obvious than that with the ri = 1 as shown in fig. 4f. this is ascribed to decrease the influence of the lid-driven velocity which means that the free convection is the dominant heat transfer method inside the cavity [13]. http://www.sciencedirect.com/science/article/pii/s0307904x13007695 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 345 1.3 velocity field figure 4g shows the velocity distribution of the fluid flow inside the cavity for ri = 2 regr = 0.01. for this designated ri number, the velocity is the highest and the velocity boundary layer is small near the moved lid-driven wall due to the high velocity of the fluid that restricted the expansion of the layer. on the opposite, it can be seen from the fig. 4g that the velocity value is zero near the others walls and at the middle of the cavity. increasing the ri number to 1.0 (fig. 4h), the impact of the liddriven motion on the velocity is less stronger and hence the region of the velocity boundary layer and the velocity distribution are larger than which for the ri=0.01 due to the role of free convection that becomes more effective in this case. the velocity distribution of the fluid is further increased and the lid-driven velocity is further decreased with increasing ri to 10 as shown in fig. 4i. this is contributed in the dominance of free convection in the cavity and increasing the heat transfer rates, this finding is in conformance with that was noted in khanafer's study [14]. the maximum velocity was noted to be reached at the contact region between the two vortices while the minimum velocity is occurred at the center of two vortices and near all walls except the sliding wall. 2 top horizontal leftward motion of the lid-driven (case 2). 2.1 flow field (streamline) in this case, the effect of the top horizontal leftwards motion of the lid-driven for three richardson numbers (0.01, 1, and 10) on the flow patterns and behavior of vortices of the flow field is illustrated in fig. 5a-c. in terms of ri = 0.01 (fig. 5a), as previously discussed within case 1, a primary vortex is generated inside the cavity due to the high velocity of the lid-driven that moves leftwards, recirculating the vortex counterclockwise. the value of the vortex is maximized in the middle of the cavity and it is minimized near the walls. the region of the fluid streamfunctions near the sliding lid-driven wall is approximately smaller than this near the others walls. this is due to the effect of the high velocity of the lid-driven. when ri is increased to 1.0 (fig. 5b), the effect of lid-driven on the flow field becomes less effective and the velocity becomes lower than that with ri=0.01. however, this mechanically-driven top lid motion resulted in building two vortices inside the cavity enclosure due to the role of free convection which becomes nearly equilibrium with the role of force convection. these two upper-right and lower-left vortices are almost having similar sizes. the upper-right vortex moves counterclockwise owing to the effect of lid-driven motion and the effect of hot wall on the right side while the lower-left vortex moves clockwise due to the role of free convection that resulted from the hot wall on the left side. as ri is further increased to 10 (fig. 5c), the effect of the lid-driven motion is also resulted in building two upper-right and lowerleft vortices but they are in different sizes and rotate in different directions. 2.2 isothermal field (temperature distribution) the effect of top horizontal leftwards motion of mechanically-driven lid (case 2) on the isotherm field (temperature distribution) for ri = 0.01, 1, and 10 is shown in fig. 5 d-f. for the ri = 0.01 (fig. 5d), the thermal boundary layer was seen on the hot right and left walls with a minimum thickness at the lower part of the hot right wall and gradually increased to reach the maximum at the upper part of the same wall. at the hot left wall, the thickness of thermal boundary layer is small at the upper part of the wall and it gradually increases at the lower part of the same wall. this is mainly due to the effect of velocity of the moved air that induces dominant of force convection in the entire cavity. with increasing ri to 1 (fig. 5e), the thickness of the thermal boundary layer on the hot wall is also increased due to the reduction of the lid-driven velocity which leads to increase al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 340 the free convection and maintain the nearly equilibrium between free convection and force convection. further increase of ri to 10, the temperature distribution becomes more obvious than that with the ri = 1 as shown in fig. 5f. this is ascribed to vanish the role of the lid-driven velocity which means that the free convection is dominant inside the entire cavity. 2.3 velocity field figure 5g shows the velocity distribution of the fluid flow inside the cavity for ri = 0.01 where the velocity is the highest and the velocity boundary layer is small near the moved lid-driven wall. in contrast, it can be seen from the fig. 5g that the velocity value is zero near the others walls and at the middle of the cavity. increasing ri to 1.0 (fig. 5h), the role of the lid-driven motion on the velocity is less effective and hence the region of the velocity boundary layer and the velocity distribution are larger than which for ri=0.01 owing to the role of free convection that becomes more effective in this case. the velocity distribution of the fluid is further increased and the liddriven velocity is further decreased with increasing ri to 10 as shown in fig. 5i. this is contributed in the dominance of free convection in the cavity and increasing the heat transfer rates. the maximum velocity was noted to be reached at the contact region between the two vortices while the minimum velocity is occurred at the center of two vortices and near all walls except the sliding wall. 3 right vertical upward motion of the lid-driven (case 3). 3.1 flow field figure 6a shows the flow pattern (streamline) for ri=0.01 and the right vertical upward motion of the lid-driven that moves in a high velocity. it can be seen that a large single vortex is generated inside the entire cavity which is rotated anticlockwise direction. the minimum value of the vortex (fluid streamfunctions) seems to be near the walls and its region which is near the hot right moved lid-driven wall, is almost smaller than this near the others walls while the maximum region is at the middle of the cavity enclosure. when ri=1 (fig. 6b), the single vortex seems to be a semi-elliptical shape approaching the right sliding wall due to the increased effective of the free convection. meanwhile, the region of the minimum streamfunction in the hot left wall of the cavity increased. as the ri increased to 10 (fig. 6c), the effect of free convection in the entire cavity becomes dominant, leading to increase the deformation of the vortex which discussed in the previous case (fig. 6b) that resulted in separating the single vortex into two vortices [7]. the generated vortices are in different sizes and rotating in two different directions. the larger vortex locates close to the hot sliding wall and rotates anticlockwise whereas the other vortex locates on the hot left wall and rotates clockwise. similarly, this was also revealed in the esfe et al.'s work [15] where they were seen the vortex migration to higher positions inside the cavity occurred and higher heat transfer rates obtained due to the change in the ri number and then the lid-driven velocity. 3.2 isothermal field the isothermal field (temperature distribution) for ri=0.01 is shown in fig. 6d. it can observe that the thermal boundary layer is contiguous on the hot right sliding wall and it is widely expanded to reach its maximum thickness at the adjacent insulated top wall. this is attributed to the direct effect of the mechanically-driven lid on the hot right wall. however, this layer is in its minimum thickness at the hot top left wall and it is gradually expanded approaching the bottom of the same wall. when ri=1 (fig. 6e), the temperature distribution is more obvious than that for ri = 0.01 due the reduced velocity of the lid-driven that caused in the occurrence of semi-equilibrium case al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 341 between the free and force convection flow. with further increase of ri to 10 (fig. 6f), the temperature distribution became semi symmetric around the vertical axis owing to the decreased effect of a lid-driven velocity. in other words, the free convection dominates the entire cavity. 3.3 velocity field figure 6g shows the velocity distribution of the fluid flow inside the cavity for ri = 0.01 where the velocity is the highest and the thickness of velocity boundary layer is small near the right upwards sliding wall whereas the velocity value is zero near the others walls and at the middle of the cavity. when ri = 1 (fig. 6h), the effect of lid-driven velocity is lesser and the velocity distribution inside the entire cavity is wider than those for ri=0.01 owing to the role of free convection that becomes more effective. consequently, the thickness of velocity boundary layer is expanded on the sliding wall and the stagnation region is increased at the hot bottom left wall. moreover, the lid-driven velocity is further decreased and the velocity distribution of the fluid is further increased with increasing ri to 10 as illustrated in fig. 6i. this is ascribed to the free convection that dominated the entire cavity. the maximum velocity emerged to be in the middle of the octagonal enclosure and the minimum velocity is at the centers of the generated vortices and near all the walls except the hot right lid-driven. the velocity distribution is a semi-symmetric around the vertical axis with a small deformation due to the force convection. 4 right vertical downward motion of the lid-driven (case 4). 4.1 flow field figure 7a shows the flow field for ri=0.01 under right vertical downward motion of a lid-driven. it is demonstrated that a large single vortex is generated inside the cavity rotates clockwise due to the high velocity of the sliding wall. the minimum value of the vortex (fluid streamfunctions) seems to be in the middle of the cavity while the maximum value is near the walls. the minimum region of the flow pattern is near the hot right downwards sliding wall and the maximum region is near the others walls due to the dominance of the force convection [16]. with increasing ri to 1, the large single vortex is split into three longitudinal vortices (see fig. 7b) with different sizes due to the increased effect of free convection that resulted in a semi-equilibrium between free and force convection heat transfer mechanism. the largest vortex locates near the hot left sliding wall and moves in clockwise direction for the difference in hot and cold temperatures on the walls. the second vortex generated due to the effect of the free and force convection, locates in the middle of the cavity and rotates anticlockwise. the third vortex that lies near the hot right wall and rotates clockwise, generated owing to the force convection. the latter vortex is almost vanished and the two former vortices are enlarged with increasing ri to 10 as shown in fig. 7c. in this case, the free convection is dominated in the cavity. 4.2 isothermal field figure 7d shows the thermal boundary layer for ri=0.01 is contiguous on the hot right sliding wall and widely expanded to reach its maximum thickness at the adjacent insulated bottom wall due to the direct effect of the mechanically-driven lid on the hot right wall. however, the minimum thickness of the layer is shown on the hot bottom left wall and it is gradually expanded approaching the top of the same wall. as ri increased to 1 (fig. 7e), the temperature distribution is more obvious than that for ri = 0.01 due the decreased velocity of the lid-driven that resulted in the occurrence of semi-equilibrium case between the free and force convection. with further increase of ri to 10 (fig. 7f), the temperature distribution became semi symmetric around the vertical axis al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 344 due to the reduced effect of a lid-driven velocity which means that the free convection dominated the cavity. 4.3 velocity field the velocity distribution of the fluid flow inside the cavity for ri = 0.01 is shown in fig. 7g. the velocity is the highest and the thickness of velocity boundary layer is small near the right downward lid-driven while the velocity value is zero near the others walls and at the middle of the octagonal cavity. when ri=1 (fig. 7h), the effect of lid-driven velocity is lesser and the velocity distribution inside the cavity is wider than that for ri=0.01 due to the role of free convection that becomes more effective. as a result, the thickness of velocity boundary layer is expanded on the sliding wall and the stagnation region is increased at the hot bottom right wall. additionally, the velocity is further reduced and the velocity distribution of the fluid is further increased when ri = 10 as shown in fig. 7i. this behavior is occurred for the free convection that dominated the entire cavity. the maximum velocity emerged to be in the middle of the octagonal cavity and the minimum velocity is at the centers of the vortices and near all the walls except the sliding wall. the velocity distribution is a semi-symmetric around the vertical axis with a small deformation due to the force convection. heat transfer field the variation in the nusselt number (nu) of the mixed convection flow for ri= 0.01, 1, 10 and different locations along the hot right wall was calculated and compared in fig. 8. for which, four different directions i.e., rightward, leftward, upward, and downward of the lid-driven were considered. the designated hot right wall was equally partitioned into numerous grids in order to calculate the average nu in different positions. the calculated nu exhibited that the heat transfer rate at the hot right wall increases with decreasing ri. the lid-driven moving towards left (case 2) had a better heat transfer rate than the lid-driven moving rightwards (case 1). this is due to the increased buoyancy effect and the increased air velocity inside the cavity [2]. similarly, the liddriven moving downwards (case 4) had a better heat transfer rate than the lid-driven was moving to upward (case 3). the vertical motion of the lid-driven whether upwards or downwards significantly increases the heat transfer rates compared to the horizontal motion (rightwards or leftwards) that exhibited a less effective on the heat transfer rates. in light of the relation of fluid motion and shape of the octagonal cavity on the heat transfer rate; it was shown that such a shape tends to generate a single circular vortex with the use of smaller ri. with higher ri values, the single vortex separated into two or three vortices due to the reduction of velocity. this is resulted in significant increases of the heat transfer rates. conclusion the mixed convection flow and heat transfer in a lid-driven octagonal cavity filled with air fluid was numerically studied using ansys 11.0 program. the horizontal rightwards, leftwards and vertical, upwards and downwards directions were considered. the effect of different positions and directions of the sliding wall and richardson number on the flow, temperature fields and heat transfer rate was examined. the results revealed the following findings: the flow pattern, temperature and velocity have significantly changed with changing ri numbers and the motion of the lid-driven. any motion in the lid-driven showed an improvement in the heat transfer rate of the cavity. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 343 for all richardson numbers, the vertical downward and the horizontal leftward lid-driven motions proved to have higher heat transfer rates compared to the vertical upward and the horizontal rightwards lid-driven motions, respectively. the higher heat transfer rates increased with decreasing the richardson number for the strengthening of flow circulation due to effects of the sliding wall motion. references [1] chin-hsiang cheng, chin-lung chen, " buoyancy-induced periodic flow and heat transfer in lid-driven cavities with different cross-sectional shapes", international communications in heat and mass transfer 32 (2005) 483-490. 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[11] m. hasanuzzaman, m.m. rahman, hakan f. öztop, n.a. rahim, r. saidur, "effects of lewis number on heat and mass transfer in a triangular cavity", international communications in heat and mass transfer, 39 (2012) 1213–1219. http://www.sciencedirect.com/science/article/pii/s0017931012003535?np=y http://www.sciencedirect.com/science/article/pii/s0017931012003535?np=y http://www.sciencedirect.com/science/article/pii/s0017931012003535?np=y http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/journal/00179310/55/19 http://www.sciencedirect.com/science/journal/07351933 http://www.sciencedirect.com/science/article/pii/s0735193312000620 http://www.sciencedirect.com/science/article/pii/s0735193312000620 http://www.sciencedirect.com/science/article/pii/s0735193312000620 http://www.sciencedirect.com/science/article/pii/s0735193312000620 http://www.sciencedirect.com/science/article/pii/s0735193312000620 http://www.sciencedirect.com/science/journal/07351933 http://www.sciencedirect.com/science/journal/07351933 http://www.sciencedirect.com/science/article/pii/s004579301400190x http://www.sciencedirect.com/science/article/pii/s004579301400190x http://www.sciencedirect.com/science/journal/00457930 http://www.sciencedirect.com/science/article/pii/s0017931015000514 http://www.sciencedirect.com/science/article/pii/s0017931015000514 http://www.sciencedirect.com/science/article/pii/s0017931015000514 http://www.sciencedirect.com/science/article/pii/s0017931015000514 http://www.sciencedirect.com/science/article/pii/s0017931015000514 http://www.sciencedirect.com/science/article/pii/s0017931015007486 http://www.sciencedirect.com/science/article/pii/s0017931015007486 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/article/pii/s0735193312001558 http://www.sciencedirect.com/science/journal/07351933 http://www.sciencedirect.com/science/journal/07351933 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 340 [12] m. muthtamilselvan, deog hee doh, "mixed convection of heat generating nanofluid in a liddriven cavity with uniform and non-uniform heating of bottom wall", applied mathematical modelling, 38 (2014) 3164–3174. 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[16] m. borhan uddin, m.m. rahman, m.a.h. khan, talaat a. ibrahim, " effect of buoyancy ratio on unsteady thermosolutal combined convection in a lid driven trapezoidal enclosure in the presence of magnetic field", computers & fluids, 114 (2015) 284–296. http://www.sciencedirect.com/science/article/pii/s0307904x13007695 http://www.sciencedirect.com/science/article/pii/s0307904x13007695 http://www.sciencedirect.com/science/journal/0307904x http://www.sciencedirect.com/science/journal/0307904x http://www.sciencedirect.com/science/article/pii/s0377042713002628 http://www.sciencedirect.com/science/article/pii/s0377042713002628 http://www.sciencedirect.com/science/journal/03770427 http://www.sciencedirect.com/science/journal/03770427/259/supp/pb http://www.sciencedirect.com/science/article/pii/s0017931014006541?np=y http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/article/pii/s0017931015001726 http://www.sciencedirect.com/science/journal/00179310 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/article/pii/s0045793015000900 http://www.sciencedirect.com/science/journal/00457930 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 344 velocity distribution body contour (m/s) figure (4): showing the streamlines, isotherms and the velocity body contours for top horizontal rightward motion of the lid driven motion with ri = 0.01, 1, and 10. stream function body contour isothermal body contour (kelvin) u u u u u u u u u (a) (b ) (c) (d ) (e) (f) (g ) (h ) (i) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 347 velocity distribution body contour (m/s) figure (5): showing the streamlines, isotherms and the velocity body contours for top horizontal leftward motion of the lid driven motion with ri = 0.01, 1, and 10. isothermal body contour (kelvin) u stream function body contour (m 2 /s) u u u u u u u u (a ) (b ) (c) (d ) (e) (f) (g ) (h ) (i) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 344 stream function body contour v v v isothermal body contour (kelvin) v v v velocity distribution body contour (m/s) figure (6): showing the streamlines, isotherms and the velocity body contours for right vertical upward motion of the lid-driven motion with ri = 0.01, 1, and 10. v v v (a ) (b ) (c) (d ) (e) (f) (g ) (h ) (i) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 344 stream function body contour v v v isothermal body contour (kelvin) v v v velocity distribution body contour (m/s) figure (7): showing the streamlines, isotherms and the velocity body contours for right vertical downward motion of the lid-driven motion with ri = 0.01, 1, and 10. v v v (b ) (c) (d ) (e) (f) (g) (h ) (i) (a) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 345 0.000 0.005 0.010 0.015 0.0 10.0 20.0 30.0 40.0 50.0 60.0 ri=0.1 ri=1 ri=10 0.000 0.005 0.010 0.015 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 ri=0.1 ri=1 ri=10 figure (8): variation of the local nu along the hot right wall for cases 1, 2, 3, and 4 and ri=0.01, 1, and 10. g tc tc th th u (b) top horizontal leftwards motion of the lid driven 0.000 0.005 0.010 0.015 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 ri=0.1 ri=1 ri=10 g tc tc th th u (a) top horizontal rightwards motion of the lid driven n u n u 0.000 0.005 0.010 0.015 0.0 10.0 20.0 30.0 40.0 50.0 60.0 ri=0.1 ri=1 ri=10 g tc tc th th g tc tc th th v (c) right vertical lid driven with moving upward (d) right vertical lid driven with moving downward v n u n u al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 205 theoretical study of direct contact condensation of laminar shear liquid film ahmed razzaq hasan assist lecturer , foundation of technical education , technical institute of al samawa department of mechanical engineering , mr.ahmedrazaq@yahoo.com received 17 july 2013 accepted 11 may 2014 abstract the present work is a theoretical study of the direct contact condensation process of saturated vapor on fully developed subcooled laminar liquid film flowing over thin liquid film on adiabatic and the inclined solid surface .a theoretical model based on momentum , continuity and energy equations . heat balance and thermal energy equation is developed to get approximate solution to describe the condensation performance of vapor on a thin liquid film . the obtained equations of solution are solved numerically using runge-kutta method and then plotting and the variation of must important parameters such as ; reynolds , prandtl , subcooling numbers and shear stress on the values of film thickness layer , bulk temperature , nusselt number (heat transfer coefficient) and velocity of the flow . the result of variation shows that the major effect parameters is attributed to the peclelt & subcooling numbers , while the other parameters is less significant . keywords : direct contact condensation ; shear liquid film ; fully developed الخـــــالصة الدراسة الحالية تتضمن دراسة نظرية لعملية تكثيف التماس المباشر لبخار مشبع على طبقة رقيقة تامة التشكيل ذات جريان طباقي الذي تم تطموير تسمتند علمى المعماد ت من السائل والذي يجري فوق سطح صلب مائل ومعزول حراريا . النموذج النظري للدراسة األساسممية للممزا وا سممتمرارية والطاقممة . معمماد ت المواينممة الحراريممة ومواينممة الطاقممة تمم تطويرلمما للح ممول علممى الحممل التقريبممي يا وتم رسممها وتامذت لوصف فعالية وسلوك البخار على الطبقة الرقيقة من السائل . المعاد ت التي ت تطويرلا للنموذج ت حلها عمدد المتغيرات مثل عدد رينولد , عدد برانتل واجهاد القص على قي سمك الطبقة المتاامة ودرجمة الحمرارو ورقم نسمل بالحسبان تأثير تل غيرلمما )معامل انتقال الحرارو ( و سرعة الجريان . اظهرت استنتاجات الدراسة ان رق برانتل و رق التكثيف لهمما اثثمر تمأثيرا ممن من المتغيرات على عملية تكثيف التماس المباشر . mailto:mr.ahmedrazaq@yahoo.com al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 206 1-introduction condensation is the heat transfer process by which a vapor is changed in to a liquid by removing the latent heat of condensation . there is four basic types of condensation are generally recognized [1]: dropwise , filmwise , direct contact condensation and homogeneous .in the dropwise condensation the drops of liquid form the vapor at particular nucleation sites on a soild surface, and the drop remain separate during growth until carried away by gravity or vapour shear . in filmwise condensation , the drops initially formed and quickly coalesce to produce a continues liquid film on the surface . in direct contact condensation , the vapor condensate directly on the subcooled liquid surface . in homogeneous condensation , the liquid phase forms directly from supersaturated vapor , away from macroscopic surface [2] . nomenclature english symbols a area [m 2 ] b width of the liquid film [m] cp specific heat at constant pressure [j kg -1 k -1 ] dcc direct contact condensation g acceleration due to gravity [m s -2 ] h heat transfer coefficient [w m -2 k -1 ] hfg latent heat of evaporation [j kg -1 ] k thermal conductivity [ w m -1 k -1 ] ṁ mass flow rate [ kg s -1 ] nu nusselt number , hd / k pe peclet number pr prandtl number q heat flux [ w m -2 ] re ryenold number s subcooling number t temperature [ c o ] u velocity in direction od flow [ m s -1 ] x coordinate in direction of flow [m] y coordinate normal to the flow [m] greek-symbols δ liquid layer film thickness [m] ε thermal diffusivity [ m 2 s -1 ] μ dynamic viscosity [ kg m -1 s -1 ] ν kinematic viscosity [ m 2 s -1 ] τ shear stress [ kg m -1 s -2 ] ρ density [kg m -3 ] ϖ, λ function defined by equation 20 θ angle of surface [ degree] subscripts b bulk f liquid o outlet i inlet s vapor , steam x local w wall superscripts + dimensionless al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 207 1.1 direct contact condensation direct contact condensation process occurs when vapor contact with a moving liquid layer (in subcooled condition) along a solid surface with negligible heat transfer to the solid boundary , the liquid motion may be induced by the body force (e.g. gravity force) or surface forces due to second phase moving (e.g. shear stress) or pressure drop . the phenomenon of direct contact condensation (dcc) has a large interest in industrial application , such as reflux condenser , tubular contractor , in cooling of rocket engines during the work of the last stage of steam turbines , in the chemical engineering industry (e.g. mixing type heat exchanger , degassers , sea water desalting by multiple distillation and by energy conversion application such as geothermal and solar system . in recent years the direct contact condensation has been of major importance in connection with nuclear industry (e.g . pressuize under normal operating conditions ) [3]. several theoretical and experimental studies about film condensation pheanmena has been studied by many investigators , beginning with nusselt [4] . who investigated the laminar film flow condensation under certain specified assumptions . later this model was modified by adding the contribution of the sensible heat term to a heat transfer coefficient . rohsenow [5]. has included the effect of cross flow on heat transfer (convection in flow direction ) within the film . hughes and duffey [6] introduced a "surface renewal theory" for dcc in turbulent separated flow, which points to an important role of the turbulence in the liquid layer. experiments and models of dcc in a rectangular duct and rectangular tank were later described by lorencez et. al. ramamurti et. al. [7] performed a dcc experiment on a thick layer of moving water in the vessel with a stagnant vapour bubble and expressed the heat transfer coefficients in terms of nusselt number as a function of liquid reynolds and prandtl number and the sub-cooling intensity . 2-analytical approach condensation in twophase system causes variations in amount and distribution of each phase . this induce variation in the local heat transfer processes due to continuous change for all thermal and hydrodynamic properties . the dcc model of this work as shown in fig .1 with inlet flow rate ṁo and subcooled inlet temperature to steam with saturation temperature ts . figure (1): direct contact condensation model al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 208 2.1 analytic assumptions 1. laminar and steady state flow of liquid layer 2. adiabatic solid surface 3. liquid inlet temperature was subcooled while the steam is in saturation temperature . 4. the gravity and shear stress are means of driving to liquid layer. 5. any instabilities or wave which may be present due to steam up flow are neglected . 2.2 heat transfer model the heat balance for model in fig .2. can be described by term of latent heat of condensation vapor and sensible heat of interface as [9] : heat balance can be written as [9] : )1.....(..............................))(( bbpbpspfg dttmdmctcmtcmdhmd   : bp dtcmd  than the balance equation becomes as : )2.(............................................................)]([ bpbspfg dtcmttchmd   for more convenient equation (2) can be written using dimensionless form , with [4] )3(.............................................................................................................. a x x o    )3.........(.................................................................................................... b m m m o     )3.......(.......................................................................................... c tt tt t os bs b     heat balance model is neglected because it is small in comparison with value of (hfg) figure (2): heat balance control element model al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 209 equation (2) becomes : )4..(...................................................................... 11 a dx md t smdx dt b b               where , )4..(................................................................................ )( b h ttc s fg osp   2.3 hydrodynamic model equation (4a) cannot be integrated without evaluation of the ṁ+ , so we will use momentum and continuity equations with the model in fig.1. to find the velocity distribution from the force balance on a segment of liquid flow   )5........(..................................................sin ay dx dp g i         the shear stress at the wall is :   )5.....(..................................................sin by dx dp g iw         and )5.(.......................................................................................... c dy du   using equations (5a) , (5b) & (5c)   )6(..................................................sin i y dx dp g dy du         integrating with following boundary conditions : al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 210 0  y w dy du  0 0   y u equation (6) can be written as : )7.(........................................ 2 sin 1 )( 2     i yy y dx dp gyu                equation (7) is velocity distirbution equation , for diminsionless becomes :   )8...(..................................................12 2 2                    yyu w iw      where ; o ow w u     the axial mass flow rate (ṁ + ) is given : )9.......(................................................................................ 0      dyum by integration , equation (9) becomes as : )9...(......................................................................2 3 am w iw             by derivative equation (9 a) , )9..(............................................................2 3 b dx d dx md w iw            therefore substitution of equations (9 a) & (9 b) into equation (4 a) , , al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 211 )10......(.................................................. )2( )1(12 3                     dx d s s dx dt w w i b     integration equation (10) with boundary conditions at dimensionless : 01,1   xatt b  )11.....(.................................................. 1 )2( )1(6 1 2 2                                w i w b s s t it is appeared that cannot be determined from equation (11) . since there is no other relation to determine the . the following approach proposed to estimate is considered to be the main point characterizing of this work . this was done through estimation of a new solution for using a specific form of the energy equation instead of the heat balance equation used previously [4]. 2.4. energy equation the appororiate energy equation has the following form : )12.......(......................................................................)( 2 2 dy td dx dt yu  it should be noticed here that the left hand side of the above equation is a function of x . so the assuming is done to simplification the equation as : onlyxf dx dt dx dt x t bxyx )( )(),(    using the non dimensional form : )12.(.......................................................................................... a u u u o   al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 212 )12(................................................................................ b tt tt t os s     and )12....(................................................................................ c u pe oo    equation (12) becomes : )13.........(............................................................ 2 2         dx dt peu y t b substituting for u + from equation (8) in equation (13) lead to : )14.(.....................12 2 . 2 2 2                                   yy dx dt pe y t w iwb      in order to find t + equation (14) is integrated with following boundary conditions for (insulation surfaces) :        yatt yat y t 0 00 equation (14) becomes : )15......(..........114 24 . 4 4 3 33                                             yy dx dt pet wb where )15.......(........................................1 a w i             in order to find the temperature t + b that defined by equation (3c) the definition of the bulk temperature may be used : al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 213 )16(...................................................................... 0 0           dyu dytu t b now , substitution of equations (8) ,(10) and (15) in to equation (16) with integration result in )17(........................................ 5 3 521 )2(2 )1(3 2                 dx dspe t w i b now , comparison of equation (17) that result from energy equation with equation (11) that result from heat balance to find the value of   dx d     )18....(.............................. 5 3 521 2 1 2 3 1 2. 16 1 2 2 2 2                                                                               w i w i w s spe s s dx d equation (18) will solved numerically using runge-kutta method [10 ,11 ] in order to calculate the thickness for any value of x + . 2.5. heat transfer coefficient calculation the local heat transfer coefficient may be obtained from heat balance   )19(............................................................ . dx md ttb h h bs fg x    used equations (11) ,(9a) & (18) with dimensionless form both hx calculated as : al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 214   )20.........(.............................. 5 3 521. 1 2 3 ... 2 2                   s spe h w x where , and the heat transfer coefficient in the form of nusselt number is obtained : )21.........(.................................................. . k bh nu x x    )21.......(.......... . 5521. 1 2 3 ... 2 2 k b s spe nu w x                   al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 215 2.6. calculation algorithm 3. result & discussion : in order to investigate the direct contact condensation process the obtained equation are solved and the important parameters of this process suh as , bulk temperature , local film thickness and local nusselt number in the flow direction , the evalution of these parameters is essential for design and figure (3): flow diagram of a approximate solution of study start end hydrodynamic model heat transfer model energy equation model numerical solving using runge-kutta method al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 216 application of the dcc systems . the effect of some parameters like reynold , prandtl , subcooled and shear stress is shown in the following points : 1effect of reynold number fig.4. shows of dimensionless thickness (  ) against the axial distance it is clear from figure increasing of (  ) with increment of ( x + ) due to the continuous condensation at the liquid – vapour interface . increasing of reynold number value and fixed others parameters pr , shear stress ratio and s lead to decrease the values of film thickness due to increase of liquid velocity and that mean less time to transfer heat with vapour at the interface surfaces. fig.5. graph between the dimensionless bulk temperature against axial distance , the observed decreasing in bulk temperature with axial distance due to bulk temperature is ( tb ,ts , to) that mean in the difference (ts-to) between vapour and liquid when is small that mean faster and good heat transfer in interface surface . so the increase of reynold number value lead to large (ts-to) because of high velocity in liquid flow . fig .6. graph between the local nussult number and axial distance , can observed from figure that nux is increasing with distance until reach to value near to constant due to heat transfer coefficient ( hx ) the decreasing in nux or (hx) with increasing of reynold number is due to increasing of velocity and that lead to increase of heat transfer resistance additionally there is no turbulent flow the only laimnar flow is available . 2effect of peclet number fig.7. drawn for various values of peclet number while other parameters are kept constant , the effect of variation of peclet number on (  ) shows a significant decrement in (   ) with increment of peclet number , this due to increasing in velocity due to increasing of reynold number (pe=re *pr) and there is another reason may changing of liquid properties because of pr changes ( pr = n/ a) . fig. 8. shown the effect of various values peclet number on bulk temperature , is clear from the plot that bulk temperature decreasing with decrease of peclet number value because the difference (ts-to) with value of (pe=1000) has rapid decreasing and that mean tb decrease too . 3effect of subcooling number the influence of changes in subcooling number s on the liquid thickness is illustrated in fig .9. this figure indicates that the decrease in s is accompanied by a decrease in (  ) this is due to the corresponding decrease in the heat transferred through the free liquid surface . other parameters which may have an effect on (  ) are related to the means of driving the liquid layer . fig.10. explain that increasing in subcooling number means small increasing of bulk temperature due to increase the difference (ts-to) where ( fg osp h ttc s )(   ) and that lead to increasing of tb . fig.11. shows the variation of subcooling number vs. axial distance and clear from the figure the increasing of subcooling number leads to increasing of difference (ts-to) due to increase (s) and that lead to increase of bulk temperature and means decrease in heat transfer coefficient due to large difference (ts-to) and that accompanied with decease in nux value due to (nux= f(hx) ). al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 217 4effect of shear stress ratio number the effect of increasing shear ratio ( interface shear to wall shear stress ) leads to increase of liquid layer due to increase the friction in interface surface between the vapor and condensate liquid due to exposed to more heat transfer area . fig . 12 . plotting between bulk temperature against axial distance , as it shown the increase of shear ratio leads to decrease the bulk temperature due to increase heat transfer rate at the interface surface because of frication forces and that can be seen also in fig.13. of increasing of nusselt number for same reason mentions above . fig . 14. shows the relation between film thickness layer (  /y ) vs. velocity profile , as natural behavior the velocity increase when we far from the wall . so , the increase in shear ratio leads to decrease of velocity due to friction between two surfaces . 4. conclusions the main points which can be drawn from above analysis and discussion are : (1) an adequate solution from the direct contact condensation was obtained . (2) the solution considers only a few parameters controlling the process – reynold number – the subcooling number – the peclet number and the shear ratio . (3) the major effect on the liquid layer thickness is atttributed to the peclelt & subcooling numbers , while the other parameters is less significant . 5. references [1] j. davis, g. yadigaroglu , “direct contact condensation in hiemenz flow boundary layers” , international journal of heat and mass transfer 47 (2004) 1863–1875 . [2] ajmal shah , imran rafiq , “numerical simulation of direct-contact condensation from a supersonic steam jet in subcooled water’’ , chinese journal of chemical engineering, 18(4) 577-587 (2010) . [3] a. segev and r.p.cellier , “ a mechanistic model for countercurrent steam – water flow” , trans. asme.j.heat transfer , 102 ,688-693 . (1980) [4] j. mikielewicz , a.m. , “therotical approach to direct contact condensation “ , int. j. heat transfer . vol. 38 , no.3 , pp.557-562, (1995) . [5] w.m.rohsenow , “ heat transfer and temperature distribution in laminar film condensation” , asme paper , no. 54-144 ,1954 . [6] hughes e. d., duffey r. b., 1991. direct contact condensation and momentum-transfer in turbulent separated flows. international journal of multiphase flow 17 (5), 599-619. al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 218 [7] ramamurthi k, kumar sunil s., 2001. collapse of vapour locks by condensation over moving subcooled liquid. international journal of heat and mass transfer 44, 2983-2994. [8] petrovic, a., calay, r.k., with, g., “three-dimensional condensation regime diagram for direct contact condensation of steam injected into water”, int. j. heat mass transfer, 50, 1762-1770 (2007) . [9] kim, y.s., park, j.w., song, c.h., “investigation of the steam-water direct contact condensation heat transfer coefficients using interfacial transport model”, int. commun. heat mass transfer, 31,397408 (2004). [10] j.p.holman , heat transfer ,2002 , 9 th , united states , mcgraw-hill higher education, 477 – 483. [11] erwin kreyszig , advanced engineering mathematics , 9 th edition , 2006 . al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 219 figure (5): effect of reynolds number on bulk temperature figure (4): effect of reynolds number on film thickness al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 220 figure (7): effect of peclet number on film thickness figure (6): effect of reynolds number on nusselt number al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 221 fig .6. effect of reynolds number on nusselt number figure (9): effect of subcooling number on film thickness figure (8): effect of peclet number on bulk temperature al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 222 figure (10): effect of subcooling number on bulk temperature figure (11): effect of subcooling number on film nusselt number al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 223 figure (11): effect of shear stress ratio number on bulk temperature figure (12): effect of shear stress ratio on film nusselt number al-qadisiya journal for engineering sciences, vol. 7……no. 2 ….2014 224 figure (13): effect of shear stress ratio on bulk temperature figure (14): effect of shear stress ratio on velocity profile template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 368 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. flexural behavior of light weight concrete slab panels reinforced with cfrp bars nameer abdul ameer alwash, babylon university, babylon, al hilla, iraq. e-mail: namer_alwash@yahoo.com ghalib muhsen habeeb, babylon university, babylon, al hilla, iraq. e-mail: habeebghalib@yahoo.com fatimah hameed naser al-mamoori al-qasim green university, babylon, al hilla, iraq. e-mail: fatimah_mamoori@yahoo.com received on 26 july 2017 accepted on 1 november 2017 published on 25 march 2018 doi: 10.30772/qjes.v10i4.482 abstract: the present study includes an experimental investigation of the behavior of simply supported lightweight aggregate concrete (lwac) and normal weight concrete (nwc) square slabs reinforced by different ratios of carbon fiber reinforced polymer (cfrp) and/or steel bars reinforcement. the experimental program consists of testing nine two-way reinforced concrete square slab models under uniformly distributed load (udl). they were of the same overall dimensions, (1050×1050×80) mm. the main variables considered in the experimental study are: type of concrete; lwac or nwc, type of reinforcement; steel, cfrp and hybrid (steel and cfrp) bars with different ratios and arrangements, the behavior of slabs with bottom and top cfrp bars reinforcement and the efficiency of using cfrp bars for strengthening slabs in two directions by using near surface mounted (nsm) technique. in this study, a waste of clay bricks was used as a coarse lightweight aggregate (clwa) to produce structural lightweight aggregate concrete (slwac). it was found that lwac slab model reinforced by cfrp bars has a lower total weight by amount 20% in comparison with nwc slab model reinforced by cfrp bars with rather a small reduction in slab ultimate load capacity by amount not more than 6.5%. however, it was found that the cfrp reinforced lwac slab model can achieve ultimate load capacity higher than equivalent steel reinforced lwac slab model by about 34.62%. nsm technique by cfrp bars in two directions of lwac slab is very effective and nearly provided the same efficiency of equivalent internal reinforcement. keywords: flexural behavior of rc slab, cfrp bars reinforcement, lightweight aggregate mailto:namer_alwash@yahoo.com mailto:habeebghalib@yahoo.com mailto:fatimah_mamoori@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 369 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. concrete (lwac) . introduction reinforced concrete (rc) is a combination of concrete and steel that has been successfully used in all types of infrastructure for more than a century. however, every material has its own advantages and disadvantages. the principal disadvantages of reinforced concrete as a structural material is its high selfweight and steel corrosion. lightweight concrete (lwc) has been used successfully in various constructions for many years. the main reason of using lwc for structural purposes is to reduce the self-weight of concrete structures. reducing the dead load of the structure is very important in earthquake regions, for tall buildings, and special concrete structures [1]. corrosion problems in steel reinforced concrete structures are inevitable and also still cause concern to most engineers. in order to eliminate the possibility of steel corrosion, non-corrosive reinforcement seems the last resort. lately, fibre reinforced polymer (frp) reinforcing bars have been developed and used as reinforcement in new construction, and in structures wherein nonmagnetic properties are required [2]. the unique advantages of frp materials such as excellent resistance to corrosion, high strength-toweight ratio, electromagnetic neutrality, and ease of handling make these materials potentially suitable for the use in reinforced concrete under conditions where conventional steel reinforced concrete has resulted in unacceptable serviceability problems. also, they are used for strengthening or repair of concrete structures by using near surface mounted (nsm) technique, which is now prevailing as a promising technology for increasing flexural and shear strength of deficient rc members [3]. in spite of the increasing use and demand, there is still a lack of adequate explanations to understand the mechanisms responsible for the behavior of lwc with frp bars as a flexural or shear reinforcement to applications in structures. 1. objective of research the basic objective of the present work is to investigate experimentally the behavior of lwac two way slab reinforced by cfrp bars and hybrid or combination reinforcement (cfrp and steel bars) by different ratios and arrangements. study the behavior of lwac slab models reinforced by cfrp bars in single and double layers. as well as investigate experimentally the efficiency of using cfrp bars in strengthening lwac two way slab in two directions by using nsm technique. also, make comparison in the weight and overall structural behavior between identical slabs in dimensions and concrete strength but differ in type of concrete; nwc or lwc which reinforced by cfrp bars. 2. slab models description the experimental program consists of testing nine two-way reinforced concrete square slab models under udl as shown in figure 1. they are of the same dimensions; 1050×1050 mm (overall dimensions), 950 mm (span length), 80 mm (overall depth), 20 mm (clear bottom cover), 16 mm (clear top cover in double reinforcement) and side covers are 25 mm. the slab models are simply supported on four edges. the ends of all slabs extended 50 mm beyond the support’s centerlines to prevent splitting (crushing) failure and any local failure. therefore, the effective span after supporting is 950 mm. in order to identify the test nwc and lwac slab models with different ratios and types of reinforcement bars, the following designation system is used: 1type of concrete: (l) for lightweight aggregate concrete, and (n) for normal weight concrete. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 370 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2cfrp bars reinforcement ratio: (f1) for 3 106176.2   f  and (f2) for 3 101411.3   f  . 3percentage of replacement cfrp bars by steel bars in hybrid reinforcement: (r0) for 0%, (r40) for 40%, (r60) for 60% and (r100) for 100% 4number of reinforcement layers: (s) for single layer and (d) for double layers. 5type of reinforcement: (i) for slab reinforced internally only and (m) for hybrid slab reinforced partially by steel reinforcement bars internally then strengthened by near surface mounted (nsm) for other cfrp bars. 6arrangement of hybrid reinforcement (cfrp and steel bars): (a1) for arrangement of cfrp bars at spacing of 240mm c/c from center of slab panel and (a2) for arrangement of cfrp bars at spacing of 480 mm c/c from center of slab panel. the parameters considered in this study based on many variables which are investigated to show their effects on the structural behavior of slab model tested under udl. these are used to study five parameters and each parametric study includes number of slab models as shown in figure 2 as following: study no.1: investigate the effect of replacement cfrp bars reinforcement of ratio 3 106176.2   f  by traditional steel reinforcement using different percentage of replacement (0, 40, 60 and 100)% and using two arrangements 240 mm and 480 mm c/c for hybrid (cfrp and steel bars) reinforcement in lwac slab models reinforced internally by single layer. this study includes lf1r0si, lf1r40sia1, lf1r40sia2, lf1r60sia2 and lf1r100si slab models. figure 1: details of dimensions concrete slab models. study no.2: investigate the effect of increasing cfrp bars reinforcement ratio 20% from lower ratio 3 106176.2   f  that can be used at maximum spacing (aci 440.1r, 2006) [4] 240 mm c/c to 3 101411.3   f  at spacing 190 mm c/c in lwac slab model reinforced internally by single layer (steel reinforcement ratio 0 s  ). this study includes lf1r0si and lf2r0si slab models. study no.3: investigate the effect of using balanced ratio of cfrp bars as top reinforcement in lwac slab model reinforced internally by single layer of cfrp bars of 3 101411.3   f  . this study includes lf2r0si and lf2r0di slab models. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 371 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. study no.4: investigate the efficiency of using cfrp bars in near surface mounted (nsm) technique in two directions at 480 mm c/c in lwac slab model reinforced internally by single layer of steel bars only. this study includes lf1r60sia2 and lf1r60sma2 slab models. to apply nsm cfrp bars, many wooden strips were installed at the bottom of the wooden mould to provide these two grooves in x and z-directions prior to concrete casting. all the grooves had rectangular cross-sections, with a size of 10 mm width and 20mm depth for cfrp bars of 6mm diameter according to (aci 440.2r, 2008) [5] which limited width and depth by equal or more than 1.5 of bar diameter. the slab were cured for 28 days and then the ply wood strips were removed, the desired grooves left at the bottom (tension) surface of the slab. the groove is then filled halfway with epoxy paste, and the cfrp bars is placed in the groove and lightly pressed. this forces the epoxy paste to flow around the bar and fill completely between the bar and the sides of the groove. the groove is then filled with more epoxy paste, and the surface is leveled. study no.5: investigate the effect of concrete type (nwc and lwac) on slab models reinforced internally by single layer of cfrp bars reinforcement of ratio equal to 3 106176.2   f  . this study includes lf1r0si and nf1r0si slab models. figure 2 details of reinforcement of slab models lf1r0si lf1r40sia1 nf2r0si al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 372 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. lf2r0si lf1r60sia2 lf1r40sia2 lf1r100si lf2r0di lf1r60sma2 continued of figure 2 details of reinforcement of slab models al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 373 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3. material properties and mix proportions the cement used in casting all the slab models was ordinary portland cement which has been brought from local market known as (kbaisa), the compliance of the cement is done according to the iraqi standard (iqs no.5, 1984) [6]. also, natural sand within the zone 2 from (al-akaidur) region was used as fine aggregate, the grading is conformed to the requirements of the limits of the iqs (iqs no.5, 1984) [6]. crushed clay bricks (waste of local bricks manufactory) were used as coarse lightweight aggregate for lightweight concrete with a maximum nominal size of 12.5 mm. it was separated by sieve analysis and recombined it to satisfying the grading according to (astm c 330, 2005) [7]. normal weight coarse aggregate of maximum aggregate size 14 mm from (al-nebai) quarry were used for normal weight concrete, the grading of this aggregate conforms to the (iqs no.5, 1984) [8]. microsilica fume (sf) under commercial name (leyco®-acc micro silica/grade 85d) has been used as a mineral admixture added to the mixture of the lightweight aggregate concrete as a partial replacement of 8% by weight of cement. sikaviscocrete-5930 (sp) is a high range water reducing admixture which was used in lwac. it was imported from sika company. clean tap water of babylon, was used for casting and curing of all the specimens. deformed steel bars (6 mm) in diameter were used in this study which was obtained from brc turkish production. the results of testing steel reinforcement according to (astm a496,2002) [9] are summarized in table 1. table 1: properties of steel bars. nominal diameter φ (mm) measured diameter (mm) weight (kg/m) yield stress y f (mpa) ultimate strength u f (mpa) 6 5.84 0.223 538 755 aslan 201 cfrp bar, of 6 mm nominal diameter, used for internal reinforcement and as a strengthening material for the recent technique known as near surface mount (nsm) strengthening. the physical properties was provided by the manufacturer, (hughes brothers), are presented in table 2. table 2: aslan 201 cfrp bar physical properties. item standards result test method tensile strength, mpa (average-3.0 sigma per astm d7205) ≥2068 2704 astm d7205 modulus of elasticity, gpa (average value) ≥124 163 astm d7205 ultimate strain 0.017 0.017 astm d7205 weight (kg/m) 0.0557 the sikadur-30 epoxy adhesive used as adhesive material with cfrp bar in nsm technique. after many trial mixes, the mix of nwc was by weight is 1:1.46:1.88 for cement, sand and gravel; respectively. the water cement ratio was equal to 0.4 with sp% weight of cement is 0.4% and cement content was 500 kg/m 3 . results of 39.2 mpa of cylinder compressive strength (150×300 mm) and 2371 kg/m 3 of air dry density at 28 days. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 374 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the mix of lwac was by weight is 1:1.091:1.127 for cement, sand and saturated surface dry (ssd) crushed bricks; respectively. the water cement ratio was equal to 0.294 with sp% weight of cement is 3.5% and sf% weight of cement is 8%. cement content was 550 kg/m 3 . results of 38.3 mpa of cylinder compressive strength (150×300 mm) and 1896 kg/m 3 of air dry density at 28 days. 4. test setup all slab models were tested in a universal testing machine with capacity of 2000 kn under monotonic loads up to ultimate load at the structural laboratory in kufa university. a rigid steel frame of channelsections, which was designed as a supporting system to obtain a simply supported condition for a square shape slab of effective span of 950 mm. the uniformly distributed load (udl) was achieved by the arrangement of the loading system as shown in figure 3 which was consisted from the following items: figure 3: loading system for test slab models under uniformly load. (1) an open box of steel plate of thickness 3 mm with inside dimensions 1000×1000×100 mm, (2) fine sand layer of 100 mm in thickness, (3) base steel plate of size 950×950×5 mm, (4) five square rigid steel legs of size 120×120×60 mm, (5) structure-loading points which consisted of six steel members from channelsection of 150×100 mm and length of 850 mm, three of these members were parallel and the other welded perpendicularly inside them for fixing the symmetric dimensions. the outer dimensions of structure-loading points were 850×850 mm and (6) two steel i-section of size 150×60×150 mm and length of 900 mm structure-loading points two steel i-section open steel box b a s e s te e l p la te al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 375 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 5. experimental results 5.1. general behavior under transverse load and cracks pattern the cracks pattern for all slab models tested under udl are shown in plate 1 and the general behavior of the tested slab models under udl can be summarized as below: at early stages of loading, the deformations were initially within the elastic ranges (linear), then the applied load was increased until the first crack became visible which was observed in the tension face of slab at about 9.47% to 12.24% of ultimate load. lf1r0si lf1r60sma2 nf1r0si lf2r0si lf2r0di lf1r100s i lf1r40sia1 lf1r40sia2 lf1r60sia2 plate 1 cracks patterns at failure for all slab models (tension) )face only) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 376 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. many cracks of flexure began to appearing in the tension face throughout slab at periods of loading with increased load, gradually increased in number, became wider and moved upwards as noting through four sides of slab models. as the load was increased further, a loss of stiffness occurred and one mode of failure appeared which can be classified as flexural failure in tension by steel yielding then concrete crushing in compression face for steel reinforced slab models. the cfrp slab models also showed similar behavior, but no rupture of cfrp occurred, the cfrp reinforcement contributed mainly in resisting the loads and increased the stiffness of the concrete slab models up to the suddenly flexural failure by crushing of concrete. the hybrid reinforcement have the same stages of mechanism, but the failure was usually recorded due to crushing of concrete in compression fiber of slab models that is happened simultaneously with few popping sounds due to rupture of cfrp bars or yielding of steel. this failure which was more gradually than cfrp slab models. in strengthened slab model by using nsm technique, the failure was observed at the nsm of cfrp bars by concrete splitting, since failure occur in the concrete adjacent to the concrete-adhesive interface due to the high tensile force exerted on the concrete under transfer of force from the adhesive. 5.2. crack width the cracking occurs when the concrete tensile stress in a slab model reaches the ultimate tensile strength. the formation of cracks were monitored throughout the test to record the width of these cracks with increasing load at each 20 kn/m 2 until near failure of all slab models in order to know the difference between types of slabs. the relation between load and maximum crack width for all slab models tested under udl are shown in figure 4. the width of the first crack load, the width of the crack at service load (70% ultimate load) and maximum crack width at failure in tension face are listed in table 3. the crack width for slab models at 70% of ultimate load was compared with crack width limitations. following (aci 440.1r, 2006) [4] the crack width for the frp rc experimental slabs is generally limited to 0.7 mm and (aci 318m, 2011) [10] limited the crack width for the steel rc experimental slabs is generally to 0.4 mm. in current study, it is reasonable to assume the crack width limitation for hybrid reinforcement (steel and cfrp bars) equal to 0.4 mm as a for the steel rc experimental slabs. study no.1: the width of the first crack load was different between slab models although they have approximately the same lwac properties and all have the same spacing of reinforcement (240 mm). they are ranged between (0.031-0.04) mm. from the figure 4, the cfrp bars slab model lf1r0si, have maximum cracks width smaller than the other slab models of study no.1 at all stages of loading. this is due to using cfrp bars reinforcement delays the crack initiation and arrested their propagation. therefore, as the percentage of replacement of cfrp bars by steel bars increase, the maximum crack width increase with taken into account the arrangement of hybrid reinforcement. at service load (at a load 70% w u), the crack width of the cfrp bars slab model lf1r0si was 0.696 mm while the crack width of the other slab models lf1r40sia1, lf1r40sia2, lf1r60sia2 and lf1r100si were 1.010, 0.720, 0.840 and 1.075 mm; respectively. which exceed the crack width limitations except lf1r0si that within the crack width limit. since, the maximum spacing for cfrp bars reinforced lwac two way slab can be adopted as three of thickness value (smax.=3h) according to (aci 440.1r, 2006). but, for steel and hybrid reinforced lwac two al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 377 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. way slab, reinforcement ratio should be increased to reduce spacing between bars in order to satisfying the crack width limitation at service load. study no.2: the increase in cfrp bars ratio 20% reduces crack width at service load by 23.56% and reduces maximum crack width especially after 140 kn/m 2 as shown in figure 4. this is due to reduction in spacing between cfrp bars. figure 4 maximum crack width versus load for all slab models study no.1 study no.2 study no.3 study no.4 study no.5 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 378 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 3: results of cracks for all slab models. slab model symbol ultimate load wu (kn/m 2 ) 1st crack in tension face (wt/wu)% crack width at 70%wu ws (mm) maximum crack width in tension face at failure wm (mm) load wt (kn/m 2 ) width wcr (mm) lf1r0si 260 28 0.031 10.77 0.696 3.40 lf1r40sia1 225 24 0.035 10.67 1.010 4.50 lf1r40sia2 241 25 0.036 10.37 0.720 4.00 lf1r60sia2 201 20 0.038 9.95 0.840 5.00 lf1r100si 170 18 0.040 10.59 1.075 7.00 lf2r0si 286 35 0.024 12.24 0.532 2.72 lf2r0di 295 36 0.018 12.20 0.440 2.24 lf1r60sma2 190 18 0.040 9.47 0.920 6.50 nf1r0si 278 32 0.025 11.51 0.560 3.02 at 70% wu, the crack width for lf2r0si is 0.532 mm within the limit, see table 4. the reducing 20% in spacing between bars, increasing the service load by about 27.78%. study no.3: the use of balanced cfrp bars ratio as top reinforcement in lf2r0di reduces crack width as shown in figure 4. the crack width for lf2r0di is 0.440 mm at 70% wu, within the limit of 0.7 mm for cfrp rc members by cfrp bars. the use of top reinforcement reducing crack width at service load by about 17.29%. study no.4: nsm slab model exhibited higher values of crack width compared to the same slab model reinforced internally at the same load level. at 70% w u, the maximum crack width of nsm slab model is 0.920 mm which exceed the crack width limitations. the maximum cracks width at failure in nsm slab model is more than it in an internally reinforced slab model by about 23.08%. study no.5: the nwc approximately at the same compressive strength of lw ac gives somewhat lower first crack width and maximum crack width at failure in nf1r0si by about 24.00% and 12.58%; respectively in comparison with lf1r0si. at 70% wu, the maximum crack width is 0.560 mm for nf1r0si within the limit of crack width of (aci 440.1r, 2006) [4] which is less than the maximum crack width for lf1r0si. 5.3. ultimate load and deflection four dial gages were placed one at the centre (dc), two at (237.5mm) from the centre of slab in both x and z-directions (dx and dz; respectively) and one at (335.8mm) from the centre of slab in diagonal direction (dxz) to measure the deflection. the recorded ultimate load, deflection and failure mode are presented in table 4. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 379 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 4: deflection at ultimate load and failure mode for each slab model. slab model symbol ultimate load wu kn/m 2 deflection mm failure mode center (dc) quarter in diagonal (dxz) mid of side x-direction (dx) z-direction (dz) average of x and z directions (da) lf1r0si 260 23.02 12.61 17.55 16.62 17.085 flexure failure lf1r40sia1 225 24.92 13.76 19.42 20.02 19.720 flexure failure lf1r40sia2 241 23.31 14.92 18.94 19.82 19.380 flexure failure lf1r60sia2 201 23.77 12.91 18.57 17.47 18.020 flexure failure lf1r100si 170 24.85 13.62 16.99 18.14 17.565 flexure failure lf2r0si 286 20.04 10.84 14.67 15.42 15.045 flexure failure lf2r0di 295 17.15 9.36 13.25 13.04 13.145 flexure failure lf1r60sma2 190 24.01 12.17 16.24 15.66 15.950 flexure failure nf1r0si 278 21.94 12.07 16.92 15.78 16.350 flexure failure 5.4. load-deflection curves when a reinforced concrete slab model is subjected to gradually increasing loads it will be in general exhibit the following stages of behavior: the first stage: is being an initial straight portion of the load-deflection curve representing (the elastic stage). this stage was characterized by an approximately linear relationship between the load and the deflection. during this stage of behavior, the section was uncracked and both the concrete and reinforcement, behave essentially elastic. the second stage: is a nonlinear portion with distinct change in slope with increasing deflections (elasticplastic stage). this stage represents the behavior beyond the initial cracking of the section where the stiffness of the slab decreased as indicated by the reduced slope of the load versus deflection curve. the third stage: is also a nonlinear portion but has characteristics in which a slight increase in load results in a larger deflection (represent the plastic stage). this stage was characterized for steel reinforcement of slab models by a decreasing slope of the curve (post-yielding), where the tension steel reinforcement reached the strain ultimate stage. in hybrid reinforcement slab models, this stage appeared with different degrees of evident depending upon cfrp bars reinforcement ratio. while, the cfrp reinforcement slab models exhibit same behavior as in the second stage until sudden (non ductile) failure by rupture if it reach to the ultimate strain of cfrp al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 380 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. reinforcement or crushing concrete or rupture followed simultaneously by crushing concrete also, depending upon cfrp bars reinforcement ratio. the load-deflection curve at central span was examined to evaluate the effect variables on the load carrying capacity and deformation ability of the slab models, as shown in figure 5. the initial change of slope of the load-deflection curves for all slab models started between 9.47% to figure 5 load–central deflection curve for all slab models al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 381 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 12.24% of ultimate load. this change in slope indicated the first cracking load as mentioned previously. beyond that, all slab models behave in a rather certain manner as the following: study no.1: the experimental ultimate load capacity of lwac cfrp bars slab model lf1r0si is higher by about 13.46%, 7.31%, 22.69% and 34.62% than that of the lwac slabs reinforced with hybrid reinforcement lf1r40sia1, lf1r40sia2, lf1r60sia2 and lf1r100si; respectively. also, lf1r0si slab model exhibited less deflection at the same load level for all stages of loading than these slabs as shown in figure 5. under udl test, the arrangement of hybrid reinforcement somewhat affect on the ultimate load of the slab model. study no.2: the increasing in the cfrp bar reinforcement ratio by about 20% in lwac slab model tested under udl lead to increase in the ultimate load carrying capacity by about 10% with significant enhancement in stiffness by reduce deflection at all stages of loading study no.3: the use of balanced ratio of cfrp bars as top reinforcement in lf2r0di which was tested under udl increases stiffness by reducing deflections but without significant increasing in the load carrying capacity. study no.4: nsm slab model lf1r60sma2 tested under udl shows similar behavior of the same slab model reinforced internally. the ratio of ultimate load for lf1r60sma2 to ultimate load for lf1r60sia2 is 94.5%. at load 160 kn/m 2 lf1r60sma2 shows suddenly reduced stiffness due to concrete splitting occur in some location of nsm cfrp bars. study no.5: figure 5 shows that the overall response of nwc slab tested under udl closely resembles that of equivalent slab model with lwac. however, nwc slab demonstrated stiffer post-cracking response than the corresponding lwac slab. the higher deflection observed for the case of lwac slab model is due to lower stiffness of lightweight aggregate crushed clay bricks and higher cement content result in lower modulus of elasticity which is lead to larger deformation than nwc. conclusions 1slwac can be produced with an average cylinder compressive strength about 37.3 mpa and average air dry density of 1896 kg/m 3 from crushed clay bricks as coarse lwa with the use of natural sand, high performance superplasticizers and silica fume. 2the lwac slab model reinforced by cfrp bars has a lower total weight by amount 20% in comparison with nwc slab models reinforced by cfrp bars with rather a small reduction in slab ultimate load capacity by amount not more than 6.5%. 3the cfrp reinforced lwac slab model can achieve ultimate load capacity higher than equivalent steel reinforced lwac slab models by about 34.62%. 4the increase in ultimate load capacity of hybrid reinforced slab model is ranged between (15.42-29.46)% when compared with steel reinforced slab model. 5the use of top reinforcement has a slight effect on ultimate load capacity but has a major effect on reducing measured central deflection by about 14.46% when compared with central deflection at service load. 6the overall response of the lwac slab using nsm technique of cfrp bars in two ways are nearly similar to that of corresponding slab using internal cfrp bars. it was found that the ratio of the ultimate load carrying capacity of a nsm technique to internal cfrp bars is 0.945. 7from load-deflection plots, the failure is brittle for slab models reinforced with cfrp bars only, less brittle for slab models reinforced by hybrid (steel and cfrp) bars depending upon steel and cfrp bars ratio and ductile in slab model reinforced by steel bars only. this means that, the use of steel bars in combination with cfrp bars (hybrid reinforcement) improved the ductility in comparison with slab model reinforced by cfrp bars only. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 382 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 8the reduction in spacing between cfrp bars from 240 mm to 190 mm shows enhancement in first crack load by about 25%. 9in general, the use of hybrid reinforcement gives improvement in first cracking load in comparison of steel reinforcement depending on the ratio of replacement cfrp bars by steel bars. 10the arrangement of hybrid reinforcement have not impact factor on the first crack load in tension face of the slab model. 11the crack pattern in cfrp reinforced slab models was different from that of similar spacing of steel and hybrid reinforced slab models, in terms of crack width and crack spacing. e.g., the maximum crack width at failure in steel reinforced slab model was wider by 51.43% than cfrp reinforced slab models tested under udl. 12according to the maximum crack width at service load (70% of ultimate load), the maximum spacing for cfrp bars reinforced lwac two way slab tested under udl can be adopted as three of thickness value (smax.=3h) according to aci 440.1r-06. references 1. arslan, g. and arioz, o., kivrak, s., tuncan, m., onur, m. i. an economic perspective of advantages of using lightweight concrete in construction, 31st conference on our world in concrete & structures: 16 17 august 2006, singapore, 2006. 2. faruqi, ma. mechanical properties and endurance limit of fibre composite bars, journal of reinforced plastics and composites 1998;17(17):1512–24., 1998 3. balendran, r.v., leung, h.y., nadeem, a. &tang, w.c. flexural strengthening of reinforced lightweight polystyrene aggregate concrete beams with near-surface mounted gfrp bars, city university of hong kong, china, 2005. 4. aci committee 440. guide for the design and construction of structural concrete reinforced with frp bars (aci 440.1r-06), aci manual of concrete practice, american concrete institute, farming hills, u.s.a., 2006 5. aci committee 440. guide for the design and construction of externally bonded frp systems for strengthening concrete structures (aci 440.2r-08), aci manual of concrete practice, american concrete institute, farming hills, u.s.a, 2008. 6. iraqi specification standards iqs no. 5. portland cement, central agency for standardization and quality control, planning council, baghdad, iraq, (in arabic), 1984. 7. astm c 330-05. standard specification for lightweight aggregates for structural concrete, annual book of astm standards, vol. 04.02 concrete and aggregates, west conshohocken, pa, united states, 4 pp., 2005. 8. iraqi specification standards iqs no.45. aggregate from natural sources for concrete and construction, central agency for standardization and quality control, planning council, baghdad, iraq, (in arabic), 1984. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 383 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 9. astm a 496-02. standard specification for steel wire, deformed, for concrete reinforcement, astm committee a-1 on steel, stainless steel, and related alloys, west conshohocken, pa 194282959, united states, 5 pp, 2002. 10. aci committee 318. building code requirements for structural concrete (aci 318m-11) and commentary, american concrete institute, detroit. mi. usa, 2011. template for academica science journal journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 591 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. response enhancement of dc motor using evolutionary intelligent fractional-order pid controller mr. nasser ali hasson al-zubaydi, al-mussaib technical institute, al-furat al-awsat technical university, babil, iraq. e-mail: nasseralzubaidy192@gmail.com received on 13 november 2017 accepted on 13 december 2017 published on 15 march 2018 . doi: 10.30772/qjes.v10i4.514 abstract: an effective intelligent controller is suggested by mixing the fractional-order pid (fopid) and fast genetic algorithms (fgas) to improve the output response of dc motor. this controller is named as fga-fopid controller, the classical fopid controllers have numerous benefits in practical implementation of many systems such as dc motor control compared with classical pid controllers, where the output response of the dc motor with fopid or with classical pid is reasonable, but it’s not satisfaysthe response enhancements. so fgas is used to slove the problem and to improve the overall output. the suggested work is confirmed by dc motor control system, and then compared with the classical pid and fopid controllers. the simulated results establish that, the suggested work is adeptness from previous work. keywords: dc motor, pid, fopid, intelligent controller, fast genetic algorithm. introduction fopid is complex model for pid system and needs more tuning of the parameters than classical pid controller, the tuning parameters of the fopid controller (piλdµ) controller is very hard to achieve [1]. the idea of this system has entered into many arenas of operative means for scientific field. numerous real schemes with the fractional variance balances which label the characteristics better. in current years, fopid anxieties additional and many academics [2]. [1] defines and growth procedure of some fractional order controller types. [3] describe the pid of the model experiment consequences show the fopid has strong strength. [4] determin very simple system to implemnt defferent types of pid systems. [5] explain fopid system for speed system design. the academics and resercher study different systems to integer and progress the control and genuineness in a diversity of actual schemes, this system is more precisely than the integer system also delivers a respectable tool for the account of procedure, fopid system is signify and better from previouse systems. this paper is ordered as follows: the model of dc motor is explained section two, section three offers the proposed work, in section four, the simulation results are explained, and finally, the conclusions and suggestions for future work are demonstrated in section five. mailto:nasseralzubaidy192@gmail.com journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 592 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1. dc motor model the dc motor is public and famous device in modern electrical power system. the model of the system is explained in in figure 1. the voltage represents the input signal and the speed represent the output. the system parameters of the system are explained in table 1 [6-8]. table 1: system parameters[6-8]. symbol name value unit j rotor inertia 0.01 kg.m^2 b friction constant 0.1 n.m.s ke emf constant 0.01 v/rad/sec kt torque constant 0.01 n.m/amp r resistance 1 ohm l inductance 0.5 h the internal torque which formed is qualified to the current of the armature. the field is expected as a constant value for simplicity. the torque is proportional to constant factor (kt) eq.(1): t= kt i (1) the electromotive force is qualified to angular velocity constant (ke). e=ke ɵ (2) the constants of the torque & emf are equals, therefore, can put k constant to describe them both. from the figure 1. (3) figure 1: dc motor model. journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 593 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. (4) the system is modeled by using laplace transform to get the equations below: (5) (6) the transfer function is designed by eliminating the current value i(s) to get the transfer function produced by rotating speed and armature voltage. (7) in order to represent the system by state variable by choosing the speed and the current as the state variables. the input is the voltage and the output is the speed as shown in the equations. (8) (9) 2. proposed controller the fopid algorithm is implemented to enhance the response by minimize the error signal between the input and the output signals. generally the fopid is govern by this equation [1, 9]: (10) where λ and µ represent gains, the old-style integer order pid controller λ and µ are set to 1 if its needed to change to classical pid controller. fast genetic algorithms (fga) are stochastic international algorithm depends on the normal evolution to produce good solutions and solve the problems. ga generate initial populace of keys applying the standard of being of the fittest to yield improved keys [10]. fga technique is used to overcome the problem in classical genetic algorithm by decreases time [11]. this algorithm is very simple for the implementation. fga used to get the best five gains for the controller to convalesce the values. best gains constants shaped when achieves the objective function which carries the greatest values. the chromosome contains 5 genes (kp, ki, kd, , λ & µ ) and the integral square error (ise) criteria is used a fitness function in this implementation [10]. in this implementation the values of each parameter for genetic algorithm are illiterates bellow: the generation number will access to = 100. the size of population = 20. journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 594 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. chromosome length should be five gens. the govern law to calculate fitness is: (11) the fitness is selected contingent difficult for the people which having high value to give good. the is a unceasing unimportant about (0.0006) summed with ise in the denominator of the equation 11 to evade the infinity . figure 2 shows the chromosome with five genes. fga is used to solve the problem based on the required values. figure 3 shows the proposed algorithm to get optimum five genes required. kp ki figure 2: chromosome representation. kd λ µ journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 595 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. start end initialize randomly with real coding the first population of fga initialize fga parameters calculate the fitness function selection, crossover, and mutation descending process best values (kp, ki, kd , λ and µ ) no. 0f generations figure 3: fga-fopid algorithm. yes call fopid algorithm call fopid controller algorithm increase the number of gen. no journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 596 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3. results the proposed work is tested by enhancement of the response of the dc motor system as shown in the simulation model in figure 4 based on matlab program. the dynamic calculations are demonstrated in eq. (12) and eq.(13): (12) (13) (14) the is constructed as shown in figure 5. figure 4: dc speed control model in matlab program. journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 597 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: control system. the final response of the system with and without controller are illustrated in figure (6-9). figure 6: the response without controller. figure 7: the response with pid. figure 8: the response with fopid. figure 9: the response with fga-fopid. journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 598 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the performance of the system is illustrated in table 2. table 2: the performance indexes with different controllers. from table 2, the overall response of the system is enhanced more by the proposed controller, the minimum ise value is produced by the fga-fopid controller, which means that the best output response is obtained. conclusions the suggested work which named fga-fopid is applied and tested in this paper by mixing fopid and fga. it is very good controller to improve the response of the dc motor compared with fopid and conventional pid system. the proposed system overcome several difficulties by mixing fopid with fga. in the proposed work the fitness function is based on ise and its very efficient choose. any change in the parameter will gives effect on the behavior of the system. the gotten simulated results are encouraged to apply this controller on other system. references 1. zhang, y. and j. li, fractional-order pid controller tuning based on genetic algorithm, in 2011 international conference on business management and electronic information (bmei) 2011: guangzhou, china. 2. m, a.v.b., et al., proposals for fractional-order pid tuning, in in the first ifac symposium on fractionalorder differentiation and its applications. 2004: bordeaux, france, . 3. i, p., et al., practical application of digital fractional-order controller to temperature control,, in 36th ieee cdc. 1999: san diego. 4. mohammed, n.f., x. ma, and e.s., tuning of pid controller for diesel engines using genetic algorithm, in ieee international conference on mechatronics and automation (icma). 2013 japan p. 1523-1527. 5. patrick lanusse, et al., ltuning of an active suspension system using a fractional-order controller and a closed-loop tuning, in the 11th international conference on advanced robotics. 2003. p. 258-263. 6. tang, w.-j., z.-t. liu, and q. wang, dc motor speed control based on system identification and pid auto tuning. in proceedings of the 36th chinese control conference july 26-28, 2017. dalian, china. 7. dorf, r.c. and r.m. bishop, modern control systems, ed. s. edition. 1995: addison-wesley, reading, massachusetts. 8. franklin, g.f., j.d. powell, and a. emani-naeini, feedback control of dynamic systems. addisonwesley, reading, massachusetts, ed. third edition. 1994. 9. m, a.v.b., et al., proposals for fractional-order pid tuning in the first ifac symposium on fractional-order differentiation and its applications. 2004. bordeaux, france. type of controller ise time response parameters tr tp o .s tss without controller 29.194 0.25 0.25 3.31 0.82 pid 3.112 0.21 0.21 1.82 0.71 fopid 2.924 0.27 0.22 0.51 1.2 fga-fopid 1.8651 0.29 0.15 0.12 1.1 https://www.researchgate.net/profile/patrick_lanusse journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 599 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 10. mohammed, n.f., x. ma, and e. song, tuning of pid controller for diesel engines using genetic algorithm. in 2013 ieee international conference on mechatronics and automation (icma). 2013. japan ieee. 11. kumar, b.r., et al., short-range fixed head hydrothermal scheduling using fast genetic algorithm, in industrial electronics and applications (iciea), 2012 7th ieee conference on. 2012, ieee: singapore. p. 1313 1318. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 431 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. modeling driver behavior for two and three lane sections in iraqi rural roads asst. prof. dr. hamid athab al-jameel, university of kufa-civil engineering dep. email: hamed.aljameel@uokufa.edu.iq eng. ali jihad kadhim, al-mustansiriayah university-highways and transportation engineering dep. email: alijkr1993@gmail.com received on 26 september 2017 accepted on 30 october 2017 published on 15 january 2018 doi: 10.30772/qjes.v10i4.492 abstract: modeling driver behavior is the corner stone for any traffic simulation model. driving behavior is a complex task to mimic the reality by simulation model. this study has focused on collecting field data from several rural road sites. these data include lane utilization, lane changing and headway. then, a simulation model has been developed for representing the driver behavior at rural roads. car-following model developed in this study is safety one. then, lane changing hybrid model has been developed according to the suggested assumptions by previous studies and collected field data to match the real behavior. gap acceptance model has been adopted from previous studies which show good consistency with real driver behavior through comparing with other characteristics such as lane changing and lane utilization. the developed model has been calibrated with field data and showed encouraging results. keywords: car-following model, lane changing model, simulation model and rural roads. introduction the need to modeling the behavior of the driver comes from the desire to improve the efficiency of the driver interaction with different types of modern automated systems, after completion of the model. these systems are able to predict the future procedures and are able to solve many problems occur at different levels of traffic conditions. moreover, these systems operate flexibly so that they can be tuned to suit different behaviors of drivers [1]. the behavior of the driver during driving is complex and varies according to the condition of the driver as well as the circumstances surrounding it either from other users of the road or characteristics of the road itself, so study the characteristics of the driver and the characteristics of the vehicle comes first to understand the interaction that occurs between the driver and the vehicle on the one hand and between vehicles on the other [2, 3]. interaction between vehicles can be defined in three terms: car-following, lane change models, and implicit model between car-following and lane change models which is gap-acceptance model [4]. details of the models will be explained in the following sections. mailto:hamed.aljameel@uokufa.edu.iq mailto:alijkr1993@gmail.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 432 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the microsimulation model is one of the tools used to understand the relationship between the three models. it focuses on the interaction between vehicles and has the ability to see the immediate results of virtual reality to implement many scenarios expected to occur on the road network. in order to determine what are the important parameters involved in building a model to understand driver behavior. it is important to define a specific algorithm for the three models to be followed as the basis for developing the simulation model [5, 6]. the aim of the present research is to modeled and represent driver behavior in rural highway by using microsimulation technique 1. previous studies it is necessary to review some of the previous studies with regard to the three models (i.e. carfollowing, lane change, and gap-acceptance models) to further understand what these models are and to prove which algorithm of these models can be used to model driver behavior to suit reality. the following sections briefly review previous studies on the three models. 1.1. car-following the car-following model (cf) plays a major role in the theory of traffic flow modeling, where it is the interaction between a vehicle and another in a single lane. the introduction of this model dates back to the 1960s. several stages of development and calibration have been carried out to make these models more reflective of reality. the safety distance model is among the most widely developed by many researchers, including gipps [7], benekohal and treiterer [8], yousif [9], and al-jameel [10]. the basic principle of this model is to avoid collisions between vehicles at any time of traffic and this is achieved by leaving enough space between successive vehicles. 1.2. lane change the lane change model (lc) comes in second place after the car-following model in participating in traffic flow modeling and has a close relationship with the driver's behavior, which is to change the location of the vehicle from one lane to another to achieve more comfortable driving conditions or as a result of circumstances forced the driver to change the lane, these conditions either from other users of the road or from the effects of road characteristics [11]. the lane change model is divided into a mandatory lane change (mlc) and discretionary lane change (dlc). mlc occurs when the driver is forced to change the lane or change the lane to convert to the intended destination, while dlc occurs in order to reach desirable driving conditions such as overtaking a slow vehicle [12]. 1.3. gap-acceptance in order to perform a change of lane, a motive for change must be provided and then an examination is made of whether there is an acceptable gap to achieve this. whereas, the gap acceptance model (ga) is responsible and controls whether a change will occur to the lane or not. among the models that have been developed is the model proposed by wang [13] , where the developed model is more reasonable for reality. in the present study, the model developed by al-jameel [14] was based on wang [13] model, and equations (1and 2) show the critical gap of lead and lag. the critical gap is the minimum time that, if available, will make the vehicle driver have sufficient time to maneuver and change his lane to another lane [15]. figure 1 shows the process of changing the corridor and the critical gap. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 433 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1: the process of changing the lane and the critical gap. ldgmin = β1[ (spl 2 / mdclvt ) – (splcv 2 / mdclcv) ] + β2(rtime) splcv (1) lggmin = β3[ (splcv 2 / mdclcv ) – (spf 2 / mdcf) ] + β4(rtime) spf (2) where; spf is the speed (m/sec) of following vehicle. spl is the speed (m/sec) of leader vehicle. splcv is the speed (m/sec) of lane change vehicle. β1, β2, β3, and β4 are parameters of calibration. mdcf is the maximum deceleration (m/sec 2 ) for following vehicle. mdclcv is the maximum deceleration (m/sec 2 ) for lane changing vehicle. mdclvt is the maximum deceleration (m/sec 2 ) for leading vehicle in the target lane, and rtime is the reaction time (sec). 2. data description (data collection and analysis) data collection is a basic step for the calibration of the developed model and is also used to find some values of the parameters involved in the evolution of the model prior to calibration. one of the most widely used methods of collecting traffic flow data is video recording. this method is still used to collect different data from traffic volumes, time headway, frequency of lane change and other data. the stage prior to data collection is to select suitable sites for case study. to choose sites there are several criteria adopted for this: it is essential that the site be free of curvature and grade, the site is free of roadworks and also the possibility of collecting data from the site easily. whereas, there is a suitable place (e.g. footbridges or bridges) in order to erect a recording camera away from the driver's sight. table 1 describes the data collected from four sites of rural roads with normal sections. two sites with three lanes for each direction are: the first site is the expressway no.1 section r4 linking baghdad and hilla, and the second site is the road between baghdad and mahmudiyah. the two sites with two lanes for each direction are the first site the road link between najaf and karbala and the second site the road between baghdad and al-kut, as is shown in figure 2. in addition to using the camera to record traffic, radar velocity was used to measure the desired velocity, speed measurement conducted a traffic volume less than 300veh/hr [16]. table 1: details of data collection from different sits of iraqi rural highways. site direction recording time for each direction date al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 434 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: data collection sites on the map. data analysis also took a rather long time because most data collection was done by camera recording. vehicles were classified into two groups: cars include passenger cars, motorcycles, taxis, small vans, and small pickups; and heave good vehicles (hgvs) include buses, lorries large van, and, trailers. figure 3 shows the traffic volume for each of the total traffic volume and hgvs. whereas, figure 4 shows the traffic volume for each lane. baghdad-hilla both direction 5 hr (08:00 am to 01:00 pm) 22-09-2016 3 hr and 50 min (06:25 am to 10:20 am) 23-10-2016 3 hr (05:30 am to 8:30 am) 21-06-2017 baghdadmahmudiyah both direction 2 hr and 15 min ( 06:45 am to 08:55 am) 10-10-2016 3 hr and 15 min ( 1:30 pm to 4:40 pm) 17-10-2016 3 hr ( 8:00 am to 11:00 am) 28-12-2016 baghdad-kut both direction 2 hr and 20 min ( 08:30 am to 10:45 am) 27-10-2016 2 hr and 30 min (06:00 am to 08:30 am) 14-05-2017 najafkarbala najaf to karbala 5 hr (07:30 am to 12:30 pm) 12-04-2017 3 hr (03:00 pm to 6:00 pm) 22-06-2017 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 435 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3: total flow of vehicles and flow of hgvs (veh/hr) with time ,a-three-lane and b-two-lane. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 436 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: flow for each lane with time (veh/hr). 3. model building and development as noted in the literature review, to develop a simulation model for traffic flow, it is necessary to choose the appropriate algorithm for sub-models (cf, lc, and ga). this study was based on the simulation model developed by al-jameel [14] on the roads for the uk, and was based on the code built by al-jameel, but was rewritten in the programming language compaq visual fortran (version 6.6) and developed to suit the rural roads in iraq. figure 5. shows the general structure of the developed model and details of each step will be explained in sequence. 3.1. model parameters 3.1.1. time headway the characteristics of both vehicle and driver should be determined either from previous studies or from on-site investigations. the characteristics are time headway, vehicle length, acceleration/deceleration rate, buffer space, desired speed, and driver reaction time. by using a recording camera and stopwatch program, the time headway was calculated, where is the difference of time between two consecutive vehicles as they pass the same point and on the same lane. determine the theoretical distribution that fits the distribution of field data time headway it is important in the process of generating vehicles into the system when you build a microsimulation model [17]. figure 6. shows the field and theoretical distribution of the data for a three-lane section where the shift negative exponential distribution was used with the shift values 0.8, 0.5 and 0.37 of the first, second and third lanes, respectively, under the volume of traffic 349(veh/hr) for the first lane, 1203(veh/hr) for the second lane, and 1651(veh/hr) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 437 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. for the third lane. the kolmogorov-smirnov (k-s) test was used to ensure that the distribution of field data was fitting with theoretical distribution and table 2 show the results of k-s test. figure 5: general flowchart for model development. htime = shift – [1/q –shift] ln (rnd) (3) where; htime : the time headway (sec). shift: the additional time such as 0.25, 0.5 and 1 in sec. rnd: the random number generated by sub-program, and q: flow rate (veh/hr). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 438 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 2: kolmogorov-smirnov results for testing the time headway distribution. kolmogorov-smirnov test (k-s) site: baghdad-mahmudiyah (10-10-2016) first lane second lane third lane flow (veh/hr) 349 1203 1651 dmax (shift negative exponential distribution) 0.042 0.051 0.040 dcr (critical value) 0.103 0.057 0.048 figure 6: observed and theoretical cumulative distribution of time headways for lane-3 with shift=0.37. 3.1.2. vehicle lengths the distribution of the length of vehicles on the road can be calculated by sensors implanted on the road surface. due to the lack of these sensors in the iraqi roads, the task of calculating the length of vehicles is not possible at the present time. therefore, it was based on a previous study conducted by al-hanna (1974) in uk and table 3 shows the mean length of vehicles for both cars and hgvs, where al-hanna found that the distribution of the length of vehicles fit with the normal distribution. 3.1.3. acceleration/deceleration rate with regard to the rate of acceleration/deceleration, there are two types of acceleration used according to ite (1999) and is the normal acceleration (i.e. comfortable acceleration) and the maximum acceleration rate, where the normal acceleration used for example to reach the desired speed, while the maximum acceleration rate used in the case of stop the vehicle suddenly. table 4 and 5 show the values of acceleration/deceleration according to the ite (1999). table 3: length of vehicles by al-hanna (1974). category of vehicle mean (m) standard deviation (m) cars 4.2 0.2 hgvs 11.2 2.4 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 439 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 4: normal acceleration/ deceleration rate (m/sec2), according to ite [18] category of vehicle acceleration (m/sec 2 ) deceleration (m/sec 2 ) cars 1.1 3.0 hgvs 0.37 1.8 table 5: maximum acceleration/deceleration rates (m/sec2) with speed value [18]. 3.1.4. buffer space the buffer space (bufs) or the distance between stopped vehicles under congestion condition, as shown in figure 1, and was adopted 1.7m as its initial values for the buffer space which is subsequently adjusted by the calibration process. 3.1.5. desired speed the desired speed measurement was done by using a speed gun. table 6 shows the rate of speed for a three-lane section, and by chi-square, the data distribution is tested and it is found to be fit with normal distribution. figure 7 shows the normal distribution of desired speed for the second lane (cars and hgvs). table 6: desired speed measurement from the site of baghdad-hilla (data collection on 21-06-2017). category lane 1 lane 2 lane 3 mean (km/hr) st.dv. (km/hr) mean (km/hr) st.dv. (km/hr) mean (km/hr) st.dv. (km/hr) cars 88.9 18.2 118 24 132.8 22.0 hgvs 78.2 16.0 90.4 16.3 94.7 16.4 acceleration (m/sec 2 ) speed (km/hr) 0-32 32-48 48-64 64-80 >80 cars 2.3 2.0 1.8 1.6 1.4 hgvs 0.5 0.4 0.2 0.2 0.1 deceleration (m/sec 2 ) 4.9 for cars and hgvs [9] al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 440 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7: normal distribution of speed. 3.1.6. reaction time the reaction time of the driver in both cases (i.e. surprised and alerted) was adopted from a previous study as suggested by johansson and rumar [19] and figure 8 shows the cumulative distribution of reaction time. figure 8: the cumulative distribution of the reaction time of the driver, according to johansson and rumar [18]. 3.1.7. traffic distribution as for the distribution of vehicles on each available lane, the traffic volume of each lane was calculated. due to the absence of loop detectors for the purpose of collecting enough data to determine the distribution of vehicles on each lane correctly, the data was collected by recording the camera towards determining the distribution of vehicles on each lane. therefore, all data obtained were combined into a single data set for each of the three-lane and two-lane section. figure 9 shows the distribution of vehicles for a three-lane section, where the distribution of vehicles on the second and third lane is higher than the distribution on the first lane. this is why most drivers avoid using the first lane because of the large number of surface defects [20], which increases the traffic volume on the second and third lane. as for the two-lane section, the distribution of vehicles on the second lane is higher of its distribution on the first lane as shown in figure 01 because of the behavior and desire of the driver. table 7 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 441 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. summarizes the equations obtained by the excel program, noting that the data was filtered from some abnormal data to strengthen the relationship. as for the distribution of hgvs on each lane, at this stage of the research and based on the site's investigations, it was based on a fixed percentage from the total traffic flow (hgvs%= 0.20). figure 9: distribution of vehicles per lane for a three-lane section. figure 10: distribution of vehicles per lane for a two-lane section. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 442 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 7: estimated equations of field data. 3.2. model rules in this section, sub-models and hypotheses used in the development of the model are identified. the model developed consists of three sub-models, namely the car-following, lane change and gap-acceptance. some of these concepts are explained in the literature review section, but in this section, each sub-model will be addressed individually and the most important features of each model will be defined. 3.2.1. car-following rules for the sub-model of car-following, the safe distance model assumes that there is sufficient distance between a vehicle and another that prevents collisions in all traffic flows situations. where it is highly efficient in the representation of reality, the reason is that it has been developed in many stages and different geometric sections of road (for example, roadworks section, weaving section, narrow lane section) and in the levels of microsimulation [9, 14, 21, 22]. therefore, in this study will depend on the model developed by al-jameel [14], where al-jameel based on benekohal [23] in the development of its model. this model consists of five cases of acceleration control of the longitudinal movement of the vehicle along the road and these accelerations are: a. acceleration of comfortable conditions. b. acceleration of the mechanical capability of the vehicle. c. acceleration to moving from stationary conditions. d. acceleration from slow moving conditions. e. acceleration of stopping the distance conditions. one acceleration of these accelerations is used according to the situation in which the vehicle is selected and the appropriate acceleration is chosen according to a flowchart as al-jameel [24] note. and then apply equations (4 and 5) to update the location and speed of the vehicle every 0.5sec (scan time was adopted 0.5sec according to alterawi [22]). spfnew = spf + aclf(t) (4) posfnew = posf + spf(t) + 0.5aclf(t) 2 (5) where; spfnew is the new speed (m/sec) and posfnew is the new position (m), of following vehicle at the end of the scan time interval. spf is the speed (m/sec) and posf, is the position (m) of following vehicle at the beginning of the scan time interval. t is the scanning time interval (sec),and aclf is the acceleration (or deceleration if negative) rate of following vehicle (m/sec 2 ). section equation r 2 three-lane section qlane-1= qtotal qlane -2 qlane-3 -- qlane-2 =0.2864* qtotal +210.85 for qtotal ≥ 315veh/hr 0.93 qlane-3 =0.63495* qtotal 242.5 for qtotal ≥ 385veh/hr 0.96 two-lane section qlane-1= qtotal -qlane -2 -- qlane -2=0.0001* qtotal 2 +0.342* qtotal +124.1 0.92 *q = flow (veh/hr) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 443 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3.2.2. lane change rules as for the sub-model of changing the lane, several hypotheses have been adopted to develop a model suitable for the behavior of the driver when changing the lane. as mentioned earlier in the literature review, the model of lc is divided into mlc and dlc, and since the study area is a normal section, the lc is the type dlc. therefore, the type of dlc will be developed only in this study. the change of the lane either towards the right lane (i.e. the slower lane) or towards the left lane (i.e. the faster lane) will occur according to the driver's interaction and desire. 3.2.2.1. lc to the left lane the driver changes his/her lane to the left lane to achieve a higher speed or to reach the desired speed in the case that it is preceded by a slow vehicle and this happens if one of the following conditions is met:  if the speed of the driver's vehicle is higher than the speed of the vehicle preceded by the value of r (the value of r suggested by ferrari [25]). r = 1040 / spfd (6) where; spfd desired speed (km/hr) of following vehicle. • if the speed of the vehicle is less than the speed desired by the value of r and the rules of the cf sub-model does not allow the speed increase and provided there is sufficient distance between the target vehicle and the new leader vehicle. 3.2.2.2. lc to the right lane in the case of changing the corridor to the right, for example, occurs when the driver wants to return to the right lane after completing the process of overtaking and this is achieved if:  the driver of the vehicle would prefer to change its lane to the right lane when its speed is less than the speed of the vehicle followed by the value of r, provided that the speed of the vehicle is less than or equal to the speed desired.  a change may occur towards the right lane when the right lane is empty for more than 300m [26]. according to the field data, a percentage of drivers prefer to stay in the second lane, even if the first lane is free of vehicles for a long distance. this percentage ranges from 15 to 20 percent of users of the second lane, whether in the section with three lanes or two lanes. figure 11 illustrates the flowchart of the process of changing the lane of the type dlc. the change to another lane is made if the previous assumptions are satisfied and there is a motive for the driver to change his/her lane. the process of changing the lane is controlled by the critical gap. in order to the driver to safely change its path, this gap must be provided as shown in equation 7. to calculate this gap, either for lead or lag, equation 1. and equation 2. mentioned in the literary reviews are based. lgg ≥ lggmin and ldg ≥ ldgmin (7) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 444 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 11: flowchart for the process of changing the lane. 4. calibration of the developed model after completing the development of the model it is important to conduct a calibration process in order to ensure that the model has the ability to represent the reality. the calibration includes checking the results of the model and comparing it with field data and correcting the parameters. this process is returned until the minimum amount of error allowed for the results of the model [27]. for the sub-model of car-following, it does not need to be calibrated at this stage of the research, but calibration will be done by comparing the traffic flow of the model results with the field data and also calibrating the sub-model of lane change. the outputs of the model is the flow of traffic and frequency of lane change and many of the outputs can be used as needed, these outputs can be measured in the model by installing a virtual loop detector on a section of the road. figure 12 shows the comparison between the results of the traffic flow of the model with the field data for a whole section of the road and table 8 shows some statistical tests (see equation 8. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 445 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. and 9.) figure 03 shows a comparison between the modeling results and the field data for each lane and table 9: proves this statistically. (8) (9) the value of geh is acceptable when it is less than 5, and if rmsep value is less than or equal to 15, it is satisfactory (as mentioned by alterawi (2014)). where; n is the number of time intervals. is the observed data at time interval i ,and is the simulated data at time interval i. figure 12: traffic flow calibration, a-for a three-lane section, bfor a two-lane section. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 446 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 13-a: traffic flow calibration, for a three-lane section. figure 13-b: traffic flow calibration, for a two-lane section (najaf-karbala). table 8: calibration -statistical test results (flow for whole section). section statistical test rmsep% <15%* geh <5* three-lanes 9..1 ...1 two-lanes 1.11 ...0 *acceptable al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 447 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 9: calibration -statistical test results (flow for each lane). section lane rmsep% <15%* geh <5* three lanes first 6.39 4.54 second 1.96 1.57 third 2.30 1.91 two lanes first 4.16 3.20 second 3.38 2.87 *acceptable as for the calibration of the model of lane change has been used frequency of lane change for calibrating. by means of gap-acceptance parameters (i.e. β1, β2, β3, and β4), the best results can be achieved between modeling and field data. where a range of (0.1, 0.1, 0.1, and 0.1) to (1, 1, 1, 1) was used for these parameters and using several runs and resetting of these parameters until the best values required for these parameters were achieved: (0.3, 0.6, 0.4, 0.7) for a three-lane section and (0.4, 0.8, 0.6, 0.5) for a two-lane section, where figure 14 compares graphically between modeling results and field data. the results show good consistency between the simulated and field data. figure 14: comparison of frequency of lane change for modeling results with field data,a-for a three-lane section, bfor a two-lane section. 5. validation of the developed model after completing the calibration process, the model needs an additional testing process with other data. validation process is the stage of ascertaining the viability of the model to conduct and achieve several applications. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 448 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 15 shows the process of comparison between the flow of the results of the model and actual data for whole model and table 10 shows that the modeling results match very acceptable with reality through statistical tests. as for the results of the speed, the model has the ability to calculate the speed for each lane, but cannot be measured realism speed with high accuracy acceptable by speed gun and for all vehicles, where the speed gun has the ability to measure the speed of one vehicle during each run of the device (speed gun). therefore, the calibration and validation of the flow of traffic were conducted only. figure 16 shows the comparison of frequency of lane change (flc) of modeling with flc of the field data. table 10: validation-statistical test results. section statistical test rmsep% <15%* geh <5* three lanes 2.34 1.56 two lanes 1.55 1.14 *acceptable figure 15: traffic flow validation, a-for a three lanes, bfor a two lanes. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 449 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 16: comparison of frequency of lane change for model results with actual data. conclusions the main conclusions that could be summarized from this study are: 1. huge amount of field data have been collected for rural roads which could be used as calibrated parameters for the developed simulation model. 2. the lane utilization has been investigated for three and two lane sections. it was found that most drivers prefer to be in the high speed lane. 3. other data have been investigated such as headway. it was found that negative exponential distribution is the best one to fit the headway character. moreover, normal distribution was found the best for desired speeds at rural roads. 4. the lc developed model, which is the sub-model, has considered more iraqi driver behavior during the process of its developing. 5. the developed model shows good consistency with field data which is the most important stage before using such model to study different traffic characteristics. the calibrated characteristics were flow and lcs. biodata dr. hamid athab al-jameel is assistant professor at the faculty of engineering, department of civil engineering, university of kufa. email; hamid.aljameel@uokufa.edu.iq. eng. ali jihad kadhim is a master student in the faculty of engineering, highways and transportation engineering dep., al-mustansiriayah university. email; alijkr1993@gmail.com. references 1. liu, a. and d. salvucci. modeling and prediction of human driver behavior. in intl. conference on hci. 2001. 2. bernhard, m. and k. schmeidler, the influence of in-vehicle information systems on driver behaviour and road safety: cost action 352. brno: ing. zdeněk novotný, 2009. 89 p. 2007, isbn 978-80-7355-083-7. 3. ahmed, k.i., modeling drivers' acceleration and lane changing behavior. 1999, massachusetts institute of technology. 4. elefteriadou, l., modeling vehicle interactions and the movement of groups of vehicles, in an introduction to traffic flow theory. 2014, springer. p. 31-58. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 450 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 5. wood, s., traffic microsimulation–dispelling the myths. traffic engineering and control, 2012. 53(9): p. 339-344. 6. lidbe, a.d., a.m. hainen, and s.l. jones, 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analysis and modelling behaviour. traffic engineering & control, 2001. 27. chu, l., et al. a calibration procedure for microscopic traffic simulation. in intelligent transportation systems, 2003. proceedings. 2003 ieee. 2003. ieee. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 254 the impact of corrosion on ( cu_37 zn) alloys welded by oxyacetylene with three types of filler rods by weight losses method assistant lecturer: aysha shawkat hasan, commission of technical education , technical college, fuel & energy eng. department email: eng_aysha@yahoo.com received 1 april 2015 accepted 27 august 2015 abstract brass is alloys of copper consisting mainly of copper and zinc, and it is welded in the same general manner as copper, but because of the peculiar properties of the alloying metals zinc, it is that must receive certain variation in welding. and because of viral application as structural materials in industries, in this work the weight losses method used to study the general corrosion behavior of 𝛼 – brass (cu – 37 zn) alloy weldments were welded by oxygen – acetylene mixture with three types of filler rods, 𝛼 – brass, 𝛼 – 𝛽 brass and tin – brass in sulfuric acid and sodium hydroxide solution at room–temperature (298k),where also the microstructure of these weldments before and after corrosion was studied. the results obtained shows that the acidic medium is more aggressive than alkaline medium for the three weldments and the total corrosion rate for three types of weldments in acidic medium was (0.085155 mpy) which was more than from alkaline medium total corrosion rate (0.030745mpy) for the same wldments, it is also found that longer exposure time to corrosion medium, leads to a lower corrosion rate while weight loss is still increasing. keywords: corrosion, brass weldments, filler rods, alkaline medium, acidic medium, oxygen – acetylene welding. ثالثة استيلين باستخدام -الملحومة باالوكسجين الزنك( 73 –ئك ))النحاس تاثير التاكل على سبا بطريقة الفقدان في الوزنمن قضبان الحشو انواع قسم هندسة الوقود والطاقة.ي، الكلية التقنية، هيئة التعليم التقنمدرس مساعد: عائشة شوكت حسن، المقدمة اضافة الزنك ، ولكننحاسطريقة لحامه بنفس طريقة لحام ال، وكون أساسا من النحاس والزنكاحد سبائك النحاس يتهو لبراصا استخدام البحثهذا في تم قد ف، كمعادن هيكلية في الصناعاتوبسبب التطبيقات المختلفة .عملية اللحامة في غريبخصائص يكسبه الملحومة بخليط و (الزنك 73 –)النحاس سبيكة الفا براصملحومات ل سلوك التآكل العام دراسةل طريقة الفقدان في الوزن حامض في محلول براص –األسيتيلين باستخدام ثالثة أنواع من قضبان حشو، الفا براص، الفا بيتا براص والقصدير -األكسجين لهذه البنية المجهرية، كما ايضا" لقد تم دراسة كلفن (892)عند درجة حرارة الصوديوم محلول هيدروكسيدو الكبريتيك قاعدية" من األوساط الكرر تاثيرااألعليها أن االوساط الحامضية هي ولقد تبين من النتائج المستحصل الملحومات قبل وبعد التاكل. الذي هو اكبر من (mpy 0.085155) انمضي كفي الوسط الحاللملحومات الرالثة الكلي معدل التاكل و الرالثة للملحومات mailto:eng_aysha@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 254 التعرض زمن كان كلما أنه أيضا ووجد ، (0.030745mpy)الوسط القاعدي للمحلومات ذاتها ليبلغ قيمته في الكلي معدل التاكل .الوزن فقدان في الزيادة استمرار بقاء مع أقل التآكل معدل كان أطول التآكل لوسط .االستيلين-وكسجين،لحام االوسط حامضيقاعدي، وسط تاكل، ملحومات البراص، قضبان الحشو، كلمات رئيسية: introduction copper and its alloys are widely used in many industrial fields, especially in marine applications, external constructions as roofs, facades and claddings. the superior properties of copper and its alloys may be attributed to beneficial, physical, mechanical and corrosion resistance properties. brass have various industrial applications and economic importance due to resistance against corrosion [1-5]. copper alloys in which zinc is the major alloying element are generally called brasses. some copper – zinc alloys have other common or trade names, such as commercial bronze, muntz metal, manganese bronze and low – fuming bronze, other elements are occasionally added to brasses to enhance particular mechanical or corrosion characteristics. addition of zinc to copper decrease the melting temperature, the density, the electrical and thermal conductivity, and the modulus of elasticity, zinc addition increase the strength, hardness, ductility, and the coefficient of thermal expansion. the color of brass changes with increasing zinc content from reddish to gold to alight gold and filler metal may depend on matching the brass color when joint appearance is important. most brasses are single – phase, solid solution, copper – zinc alloys with good room – temperature ductility. brasses containing about 36 percent or more zinc have two microstructure phase designated alpha and beta. copper and most copper alloys are readily soldered with commercial solders. most copper alloys are easily fluxed, except for those containing elements which from refractory oxides. (e.g., beryllium, aluminum, silicon or chromium). special fluxes are required to remove refractory oxides that from on the surface of these alloys [6]. because of the high corrosion resistance of the brass it is widely applied as structural materials in industries. for the brass, the conventional fusion welding has some obvious limitations. during the fusion welding, the evaporation and melting loss of a large amount of zn element resulted in the failure of welded joint due to lower steam point of zn which is (907 o c)[4]. the alloying metal zn is greatly affected by the high temp of the flame, unless proper precautions are taken. these metals will combine with the oxygen and pass off as white vapor, and leave a weld of different composition and color [7]. the alloying metal zn is greatly affected by the high temp of the flame, unless proper precautions are taken. these metals will combine with the oxygen and pass off as white vapor, and leave a weld of different composition and color [8].it is sometimes difficult to determine why welds corrode; however, one or more of the following factors often are implicated: weldment design, fabrication technique, welding practice, welding sequence, moisture contamination, organic or inorganic chemical species, oxide film and scale, weld slag and spatter, incomplete weld penetration or fusion, porosity, cracks (crevices), high residual stresses, improper choice of filler metal, final surface finish [5]. the researcher nooredeen fathalla soulyman (2005) studied the general corrosion behavior of 𝛼 – brass (cu – 37 zn) alloy weldments in sulfuric acid and sodium hydroxide solution at room– temperature (298k) by using the electrochemical cell corrosion test method[9]. ashok kumar , r. shukla and a venk at chalam (2013) studied copper aluminum metals and brass alloy in the form of 8 x 6 x 0.3 cm strips under different medium is undertaken and study reveals that corrosion rate increases in the following order al > fe > cu > brass and for the medium in which the corrosion takes place in the order of hno3 >h3po4 > h2so4 > hcl > ch3cooh [2]. w.f. savage , e.f. nippes and t.w. miller (2013) studied the partially melted regions of gas tungsten – are welds made in a 70 cu – 30 ni [10]. and because of viral application as structural materials in industries, in this work the general corrosion behavior of 𝛼 – brass (cu – 37 zn) alloy weldments in sulfuric acid and sodium al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 252 hydroxide solution at room–temperature (298k), also the microstructure of these weldments before and after corrosion was studied for the specimens 𝛼–brass (cu – 37 zn) alloys were welded by oxygen – acetylene mixture with three types of filler rods, 𝛼 – brass, 𝛼 – 𝛽 brass and tin – brass by weight losses method. experimental materials different samples of 𝛼 – brass alloys were used in this work. the brass is a copper –30zinc which shown the chemical composition of it in table (1), having mainly alpha phase structure in the heat treated condition with a fine dispersion of lead particles. it has excellent machinability, good cold forming properties, with a high resistance to dezincification [11]. different welding filler rods used in this work, the principle types of the filler rods shown in table (2). equipment and experimental the following machines and equipment were used : 1. saw bar. 2. electrical furnace for preparing samples for welding process. 3. oxy – acetylene welding machine. 4. (𝛼 – brass) weldments 5. three types of filler rods (cu – 30 zn ), (cu – 40 zn ) and tin – brass. 6. milling machines. 7. sensitive balance device (four digits). 8. sulfuric acidic concentrated solution ( h2so4). 9. sodium hydroxide solution (naoh). 10. distilled water with ph=7.4. 11. ph meter. the preparation of specimens for welding purpose the preparation samples for welding purpose was done by the following steps: a. cutting the samples 1. the samples cut from the plate of brass with dimension (250mm) length and (122mm) width by saw bar. 2. the edge of the sample were chamfered by milling machine with grove angle (70 ◦ ) . al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 255 3. cleaning the samples by alcohol from oils and grease . 4. fixing the samples by back strip to preparing them for welding[12] . b. preheating the samples preheating the specimens results in the rapid conduction of heat from the weld joint in to the surrounding base metal due to its relative high thermal conductivity. this makes achieving fusion and weld penetration difficult [1].heating the samples in electric furnace to (200-300) o c and preparing the samples for welding, the most common method to counteract the effects of thermal conductivity and which is used in this work. the second steps followed to finish the welding operation by oxy – acetylene, and the flame which its properties shown in table (3) were: maintain root gap between two joint parts in limits of (3mm) to obtain good penetration for welding metals, the distance between the internal core of welding flame and the specimen welded is (3-6) mm, the flat position welding process by back hand technique was used with low oxidation flame[8] and finally a suitable flux used, to dissolve any oxidation and to give a film or protecting to the fused material to prevent oxidation [11]. corrosion tests the following steps were followed to prepare the specimen[13], for studying the corrosion behavior of the weldments: a. weld zone preparing  cutting the weld zone by cutting tools with dimensions of (1x1) cm 3 .  grinding them using wet grinding (120, 220, 240, 320, 400, 600) to prevent the increase of temperature, which will change the compositions of the materials.  polishing specimens by aluminum oxides with diamond and paste.  washing specimens by distilled water and degreased with ethanol and dried [8].  weighing them by sensitive balance with four digits accuracy to fixing the initial weight for the specimens. b. corrosion medium after prepare the specimens for the weld zone, the specimens marked to recognize one from another and make hole (2mm) in each specimens to hung by tungsten wire immersion in selected medium in backer with (1000 mm) capacity. two mediums used to corrosion tests in this work:  acidic medium three samples of weldments, which were welded by brass (cu–30zn), brass (cu–40zn) and (tin – brass) filler rods were immersions in h2so4 solution with purity of 98% and ph= 2. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 254  alkaline medium three samples of weldments, which were welded by brass (cu–30zn), brass (cu – 40 zn) and (tin – brass) filler rods were immersions in naoh solution with purity of 96% and ph = 12. c. intervals of corrosion test the corrosion test were done in 5 days (120 hours): first interval: for 1 day, 24 hour. second interval: for 2 day, 48 hour. third interval: for 3 day, 72 hour. fourth interval: for 4 day, 96 hour. fifth interval: for 5 day, 120 hour. d. calculation of corrosion rates 1. after the corrosion tests finished the samples taken from the corrosion mediums and cleaned from the oxidation layers which caused from the corrosion and by using smooth brush and then immersed in (hcl) and then washed and dried and weighing the samples. the previous steps was followed at the end of each interval for corrosion to know the difference of weight between the before and after the corrosion. the loss of weight was used to know the corrosion, and the formula for calculating the corrosion rate is[14]: corrosion rates (miles per year) = 534 w / dat (1) where 534 : constant. w : weight loss in mg . d : density of specimen in g/cm 3 = 8.379 g/ cm 2 a : area of specimen in sq. in = 0.396 t:exposure time hour. 2. total corrosion rates (crt) also calculated from the equation (1) by substitute instead of (w) the difference between the initial weight and the last weight, and instead of the time the total exposure time to corrosion medium which was (120hr). results and discussions the general behavior of corrosion and the corrosion rates for the weldments: 1. the general corrosion behavior for (𝛼 – brass) (cu – 37 zn ) alloy weldments by three different filler rods was obviously shown from figure(1).the corrosion rate is increasing with high percentage until the time reaches to (3hr) then its start, to decrease sharply with increasing the period of exposure until the time reaches to (20hr) and the decreasing continue but in slowly shape. with increasing time of corrosion the corrosion rate decrease al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 254 until it be there is no corrosion or it at zero and this result was for the three different weldments but with different percentages. the maximum total corrosion rate done in (cu–40zn) weldments which equal to (0.002775mpy), and minimum total corrosion rate was done in (cu–30zn) weldments which equal to (0.000075 mpy), as shown in figure(2), referring to studies and researchers in [9]. the possible reason for this because the (cu-40zn) weldment has the maximum content of zinc (40 %), and zinc tend to oxidize due to its electrode potential (-0.76v), and the corrosion of (tin – brass) weldment (cu –39 zn –1sn) is less than the first one due to the percentage of zinc (39 %) and tin (1 %), and since the tin ' s electrode potential is (+0.15 volt), this weldment was less active. and the minimum corrosion which done in the (cu – 30 zn) weldment was due to the (30 %) of zinc content. the chemical equation of elements in the weldments with sulfuric acid is: m + h2so4 ⥨ mso4 + h2 where m is zn, sn & cu. 2. while the samples which immersion in the (naoh) as alkaline medium the corrosion rate increasing with high percentage until the time reaches to (5hr) then decreasing sharply with increasing the period exposure until the time reaches to (20hr) and the decreasing continues but slowly. with increasing the time of corrosion, the corrosion rate decrease until it be there is no corrosion or it at zero and this result was for the (cu –30zn) weldments, and the same behavior for the another two weldments just the difference for the time reaches to the peak rate of corrosion was at (3hr) but with different percentages and this behaviors clearly show in figure(3).the total corrosion rate for three types of weldments with alkaline medium immersing can be seen in figure(4) which shows the maximum total corrosion rate in (cu–30zn) weldment with (0.00040833mpy) and minimum total corrosion rate in(cu–40zn) weldment with (0.00036667mpy). the chemical equation of elements in the weldments with alkaline is: m + 2naoh+2h2o ⥨ na2m(oh)4+h2 where m is zn, sn & cu. 3. in general the total corrosion rate in acidic medium for weldments with three types of filler rods was more than from the specimens in alkaline medium as shown in figure(5)and the peak total corrosion rate was (0.085155mpy) in acidic medium, meanwhile in alkaline medium the peak total corrosion rate was (0.030745mpy) referring to the studies and researchers in [15], all these obviously shown in figure(6) which represents the compartive between two mediums for the total corrosion rate for specimens were used in this work. 4. the reason for the low corrosion rates with increased exposure to the medium of corrosion due to the slow time speed of electrochemical interaction with continued exposure time due to form layers of membrane or remnants of corrosion on weldments surfaces hinder the continuation of the process of electrochemical corrosion, which leads to reduced rates with the continued erosion of time. and also because of depletion of dissolved oxygen in the medium of corrosion, that at the beginning electrochemical corrosion test interaction which happens quickly lead to a high erosion rates, but with the passage while less dissolved oxygen ratio, leading to increased the concentration of hydrogen ions that accumulate when the lift pole where interactions hinder corrosion, this is named polarization referring to studies and researchers in[5]. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 254 discussions 1. from the obtained results for the specimens were immersed in acidic medium its clearly show that the corrosion effort be more aggressive due to the following order of corrosion activity: cu – 40 zn > tin – brass > cu – 30 zn . 2. from the obtained results for the specimens were immersed in alkaline medium its clearly show that the corrosion effort be more aggressive due to the following order of corrosion activity: cu – 30 zn > tin – brass > cu – 40 zn 3. the corrosion rates in acidic medium were higher than the corrosion rates in alkaline medium. 4. the corrosion rate decreasing with increasing the interval of the corrosion due to the slow time speed of electrochemical interaction with continued exposure time due to form layers. references [1] american welding society, 1992. welding copper and copper alloys , 550 n .w. le jeune road , miami , fl 33126. [2] ashok kumar, r. shukla and venkatachalam, 2013. studies of corrosion and electrochemical behavior of some metals and brass alloy under different medium, rasayan journal chemistry, 6(1): 12-14. [3] billy, f., 1985. engineering material hand books, translated by dr.hussein baqir, technical college, baghdad, iraq. [4] china machine press, benjing, welding hand book, 1992, 2: 469-471. davis, j.r. and associates, 2006. corrosion of weldments, [5] stephen c. d., 2003,galvanic corrosion ,university of delaware, u. s. a. [6] elmahdy g.a. amro k.f. dyab, m. ayman atta, a. hamad al-lohedam,2013. brass corrosion under a single doplet of nacl, international journal of electrochemical science, 8:9858-9867. [7] rauf, a. and e. mahdi 2012. evaluating corrosion inhibitors with the help of electrochemical measurements including electrochemical frequency modulation, international journal of electrochemical science, 7: 4673-4685. [8] robert, j., m.e. kehl, 1918, oxy – acetylene welding practice, consulting mechanical engineering, american technical society, chicago. [9] nooreldeen fathalla soulyman, 2005, corrosion behavior of some brass welding in different medium, b .sc. thesis, republic of iraq, ministry of higher education and scientific of technical education technical college / baghdad. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 254 [10] savage, w.f., e.f. nippes and t.w. miller, 1976. microsegregation in partially melted regions of 70 cu – 30 ni weldments, welding journal , july: pp: 181-187. [11] voortand f. george, 2004. asm metals hand book, asm international materials collection metallurgaphy and microstructure. [12] asm hand book , 2004, metallurgaphy and microstructure, volume(9), 107 . [13] asme, 2010. specification of welding rod and electrode, part c. [14] velayutham k., u. arumugham, b. kumarugur-rubaran, p. gopal, 2013. evaluation of the anti-corrosive coating on railway bogie components, international jounal of engineering and advanced technology, 3(2): 2249-8958. [15] zhuo yuan chen, 2005, the role of particles on initial atmospheric corrosion of copper and zinc, royal insitute of technology, sweden, p(29). table 1: chemical composition for the base metal (𝛼 – brass ) % percentage element % percentage element o.o44 bi 62.68 cu 0.0043 sn 0.00131 al 37.07 zn 0.156 fe 0.021 mn 0.00125 ni 0.002 sb 0.0106 pb 0.0031 si table 2: principle types of welding rods chemical composition% type of filler rod procedure cu 30 zn r cu – zn oxy – acetylene welding cu 40 zn r cu – zn cu -39 zn – 1 sn r cu – zn – sn table 3: cases of welding brass by oxy – acetylene[8] gas consumption l/ min pressure kg/cm 3 plate thickness mm tip size max min c2h2 max o2 min 70 37.5 1.54 0.77 8.19 70 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 244 figure (1) : corrosion rate in sulfuric acid immersion for three filler rods figure (2): the total corrosion rates for three weldments immersed in acidic medium. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 244 figure (3): corrosion rate in alkaline immersion for three filler rods figure (4): the total corrosion rates for three weldments immersed in alkaline medium. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 244 figure (5): the comparative of the average corrosion rate for three types of weldments between two mediums. figure (6): the comparative of the total average corrosion rate for three types of weldments between two mediums. evaluation the wells water properties in the border line between iraq and ksa for different uses al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 37 evaluation of groundwater properties in borderline between iraq and kingdom of saudi arabia for different uses dr. yahya k. at-temimi babylon university, college of engineering, civil engineering department received 23 august 2015 accepted 23 november 2015 abstract the properties of groundwater in some wells digging on the border of iraq with ksa along 400 km from al-nekheab at west to al-salman at south of iraq were evaluated. eleven wells were chosen as a case study depended on variable of water depth and stratum properties. water samples were taken at two periods the first one at summer and the other at winter reason. the chemical properties of these samples were compared with the standard limits to evaluate the quality of water for different uses. the main parameters used for evaluation process are negative and positive ions, total dissolve salt, electrical conductivity, and turbidity. finally, conclude the usages of water of investigated wells were un-permitted for drinking purposes except well no.10 unless treated by purifying process, but can be used for irrigation for soil which has high permeability and good drainage in addition to plant have high strength for salinity. in the other side all wells mostly used for livestock usages and poultry. for industrial usages only well no.(10) can be used for industry of cement. while all wells can be used for building purposes except wells no. (1, 2, 7, 11). key words: tds, electrical conductivity, turbidity, drinking water standards, industrial water standards. تقييم خواص المياه الجوفية في الحد الفاصل بين العراق والسعودية لالستعماالت المختلفة د.يحيى كاظم حسين جامعة بابل، كلية الهندسة، فسم الهندسة المدنية الخالصة الشعرط الدعدي ا العراقعي مع الجا ع في بعض االبار التي حفرت في مواقع لىع المياه الجوفيةتهتم هذه الدراسة بتقييم خواص كم بدا من النخي في غرب العراق يحت السعىما فعي ونعوب الععراقت اختيعر احعد لشعر بمعرا التمعا ا لىع 044السعو ا يبطول الكيميائيعة مواصفات اللمق الماء يخواص الطبقةت وم العينات كا في فترتين زمنيتين، االيل في الصيف ياالخرى في الشتاءت المقعاطي هعذه الميعاه مع تىعس االسعتعماالتت وليعة قور ع مع المععاطير المطىوبعل لكعع اسعتعمال ليعر تقيعيم م ئمعة لهذه العينات االطو ات السالبة يالمووبة ياالم ح الذائبة الكىية باالضافة ال العكورة يالموصعىية شمىقييم تالالرئيسية التي استعمى في لمىية al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 30 ( الطمكعن اسعتعمالها الغعرا الشعرب معالم طعتم اسعتعمال 04ا مياه هعذه االبعار مالعدا البمعر رقعم ص الدراسة ال خى الكهربائيةت لكن طمكن استعمال مياه هذه االبار فعي را المخاصعيع الاراليعة التعي لهعا مقايمعة ويعدة لىمىوحعة يفعي اراضعي ات لمىيات التنقية البمعر رقعم فقع ى غالبا كع االبار طمكن استعمالها لىماشية يالدياونت اما في الصعنالة ف فا طة لالية يتصرطف ويدت يمن احية اخر (00, 3, 2, 0طمكن استعمالل في صنالة السمن بينما كع االبار طمكن استعمال مياهها الغرا البناء ما لدا االبار ( 04 list of acronyms ca ++ calcium cl -1 chloride co3 carbonate ec electrical conductivity fao food and agriculture organisation h2s hydrogen sulphide hco 3 bicarbonate idws iraqi standard for drinking water k + potassium mg 2+ magnesium moh ministry of health na + sodium no -3 nitrate osc organization of central of statistic ph hydrogen ion concentration po -4 phosphate mg/l parts per million sar sodium adsorption ratio so -4 sulphate t.h total hardness tds total dissolved salt who world health organisation w.c.t with compared to introduction water plays important roles in the life of the community, as it needs to sustain life directly by using it for drinking and in making its own food, and indirectly, as in agriculture, industry, power generation, health and other services. investigation of alternative resources for surface water was the main task for researchers because shortage and the degradation of surface water quality at last 10 years ago. climate change in the world and extreme iraq’s climate (dry and lower rainfall about 40 cm 3 /year)(moe 2006) rising importance of groundwater studies. so many researchers were al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 37 studied groundwater properties such as the water quality and its effect on nutrients availability for corn in sulaimania region was studied by mam rasool (mam rasool, 2000). also al-manmi was investigates chemical and environmental of groundwater in sulaimaniya city and there uses (almanmi,2002). while sadiq was discusses groundwater availability in south of iraq (sadiq,2013) as well as alhusseini was analyse groundwater flow of bahr al-najaf area (alhusseini,2013) also al-salim was discusses recharging of groundwater processes in wadi al-kassab catchment's area(al-salim,2013). the iraq land were divided into five physiogarghic zones (sadiq 2013) as illustrated in figure (1), the zone number five (region of study) has deep water aquifer and lower quantity. description of the region of study the distributions of investigated wells were on the border strip between iraq and ksa along 400km from al-nekheabe at west of iraq to al-salman at south of iraq. this wide area not have any surface water resources (rivers, canals, lakes …etc.). therefore, it is depended mainly upon groundwater. the geological description of this area is sand valleys with hard stratum for sand and calcite rocks (sadiq 2013). eleven wells were used for evaluation the quality of water for different uses. all wells information’s were listed in tables (1) and (2). tests were executed in labs of environment directorate of baghdad in 2008. suitable of groundwater uses drinking water the using of water for drinking purpose required meeting water specifications for drinking usages. who and idws were presenting a limitations for using water for drinking as listed in table (3) (idws 1998; who 2006) . figures from (2) to (10) can observing all wells found hade over in ca ++ , mg ++ , na , and t.d.s except well no. (10), all wells agreement with ph value except well no. (11), and all wells have hardness, so groundwater of well no. (10) can be used for drinking purpose when an process used to eliminate sulphate. irrigation usage "the water used in irrigation depends on type of soil and kind of plant" (al-saed 2006). wilcox, schofield, doneen, eaton, and thorne and thorne were presented more than system to classification the irrigation water(al-manmi 2008). while in this study procedures of usa salinity lab. was used. it can be classified the water for many zones depending on sodium adsorption ratio (sar) and electrical conductivity( ec) as illustrated in figure (11). the usage of wells water for irrigation can be evaluated. the water characteristic of all wells except well no. 10 can be used for soil which has high permeability and good drainage in addition to plant have high strength for salinity, while water of well no. 10 can be used for irrigation for most plant, as shown in table(4). livestock drinking usages livestock have an ability to drinking water with ionic concentration more than human ability (clark 1977), so properties of water used for livestock drinking were lower than for humane drinking use. ayers and westcot presented a classification for drinking water for livestock as shown in table(5) (ayers 1994). a according to this classification well no. (10) regarded has al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 37 excellent rating, wells no.(1,2,4,6,7,9,11) has very satisfactory rating, and wells no. (3,5,8) has satisfactory rating for livestock but unfit for poultry. industrial usages the industries that may be construct in study zone, according to availability of raw materials and there circumstances, were cement and oil industries. water standard for cement and oil industries usages was presented by hem as illustrated in table (6)(hem 1991). therefore just well no.(10) was satisfies requirements for industry of cement while other wells may be need other treatments. table (7) summarize evaluations for industrial usages. water for building usage classifications of altoviski, shown in table (8)(al-manmi 2008), for water that use in building usages, the wells water were evaluated. all wells can be used for this purposes except wells no. (1, 2, 7, 11) because this wells have ( mg ++ ) ion over water requirements. conclusions the deducing was obtaining according to previous evaluations, were the location of well and excavation level with respect to sea level don’t have effect on water properties, also the behaviour of concentration of anions, cations, and t.h. for investigated wells was approximately the same. moreover the usages of water of investigated wells were un-permitted for drinking purposes because have high concentration of anions, cations, and hardness except well no.10 unless treated by purifying process. for irrigation all wells except well no. 10 can be used for soil which has high permeability and good drainage in addition to plant have high strength for salinity, while water of well no. 10 can be used for irrigation for most plant. while for livestock usages all wells mostly used for livestock usages and poultry. for industrial usages the investigated wells were showed weakness for industrials usages except well no.(10) that satisfies requirements for industry of cement. while all wells can be used for building purposes except wells no. (1, 2, 7, 11). references [1] alhusseini, t. r. abdul-mehdi, (2013), ” transient groundwater flow analysis of bahr alnajaf area using fuzzy approach”, department of civil engineering, college of engineering, university of al-mustansiriyah, ph.d. thesis. [2] al-manmi, d. a. m. a. (2008), “water resources management in rania area sulaimaniyah neiraq”. department of geology, college of science, university of baghdad, . ph.d. thesis. [3] al-saed, k., and n., fatihy (2006), "validity and observation acceptable the irrigation water". recommended paper, agriculture research centre, egypt [4] al-salim, t. h., (2013), “rainwater harvesting of wadi al-kassab catchment's area by weir construction, west of mosul city / north of iraq”, the international conference to achieve sustainable development in iraq, ministry of higher education and scientific research, baghdad, iraq al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 33 [5] ayers, r. s., and westcot, d.w. (1994), "water quality for agriculture irrigation and drainage", fao, rome, italy. paper 29, rev. 1. [6] clark, j. w., viessman, w. and hammer, m.j. (1977), "water supply and pollution control". new york, usa., welly & sons. [7] hem, j. d. (1991), "study and interpretation of the chemical characteristics of natural water". usgs water supp. paper no. 2254, 263. [8] idws (1998), "guidelines standard for drinking water". public halthy, iraqi. [9] lamaddalena, n. (1997), “integrated simulation modelling for design and performance analysis of on-demand pressurized irrigation system", technical university of lisbon, lisbon. ph.d. dissertation. [10] moe (2006), “state of the environment in iraqi company report 2006”. baghdad, iraq. the directorate of maritime inspection [11] mam rasool, g.a., 2000, "steady of water quality and its effect on nutrients availability for corn in sulaimania region", m.sc. thesis, collage of agriculture, university of sulaimania. [12] sadiq, j. b. (2013). “groundwater in iraq”. the international conference to achieve sustainable development in iraq, ministry of higher education and scientific research, baghdad, iraq. [13] suares, d. l., (1981), "relation between phc and sar and alternate method of estimating sar of soil or drainage water", soil science society american journal 45:469-475. [14] who, (2006), "guidelines for drinking water quality", recommendations, 3rd ed. geneva vol.1. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 37 table (1): description of wells. direction elevation w.c.t sea level (m) elevation of excavation w.c.t sea level (m) name of well well no. e n 42 0 13 ' 785 " 31 0 02 ' 347 " 355.5 136 al amger 1 43 0 15 ' 913 " 30 0 17 ' 304 " 372.3 87 al bateen 2 43 0 19 ' 547 " 30 0 19 ' 083 " 389 144 al gazali 3 43 0 27 ' 881 " 30 0 20 ' 615 " 392 112 al-hakim 4 43 0 29 ' 408 " 30 0 14 ' 986 " 398 118 al-hamza 5 43 0 34 ' 445 " 30 0 03 ' 785 " 395 67 treeq al-huseen 6 43 0 38 ' 999 " 30 0 04 ' 507 " 390 70 al-sufawi 7 43 0 45 ' 846 " 29 0 57' 309 " 400 70 alfarise 8 44 0 14 ' 504 " 29 0 35' 154 " 230 -30 sallah 9 44 0 43 ' 077 " 29 0 12 ' 000 " 198 -44 anssab 10 45 0 18 ' 067 " 29 0 09 ' 036 " 110 -130 fatema 11 table (2): water quality collected from wells. no. of well well name ca ++ mg/l mg ++ mg/l na mg/l cl mg/l so4 mg/l t.h mg/l t.d.s mg/l ph turbidity ntu 1 al amger 360 336 280 242 1290 1890 2040 7 58 2 al bateen 324 336 290 257 1290 1800 2140 6.92 86 3 al gazali 288 215 461 368 1260 1620 3756 7.64 4.19 4 al-hakim 396 215 301 334 1220 1890 2240 6.8 83.5 5 al-hamza 396 258 437 257 1116 2070 3618 7.28 7.52 6 treeq alhuseen 360 150 343 183 827 1530 2658 7.92 5.45 7 al-sufawi 360 288 508 312 1236 2106 4188 7.61 50.12 8 alfarise 360 215 438 212 1172 1800 3538 7.96 16.1 9 sallah 357 152 221 2.5 677 1520 1480 7.54 278 10 anssab 190 115 105 85 41 950 385 8.02 110 11 fatema 722 184 300 325 177 2565 2230 6.18 3.8 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 37 table (3): water quality for drinking water (idws 1998; who 2006) ca ++ (mg/l) mg ++ (mg/l) na (mg/l) cl (mg/l) so4 -2 (mg/l) t.h (mg/l) t.d.s (mg/l) ph turbidity ntu idws 74 74 244 274 274 500 0444 77ت7-7ت who 37 027 244 274 274 ---0444 77ت7-7ت 5 table(4): ec, sar, and evaluation of water for investigated well no. of well well name ec (ds/cm) sar(epm) zone 1 al amger 3.99 2.5 c4-s1 2 al bateen 4.22 2.7 c4-s1 3 al gazali 5.56 5.0 c4 -s1 4 al-hakim 4.44 3.0 c4-s1 5 al-hamza 4.68 4.2 c4-s1 6 treeq al-huseen 3.736 3.8 c4-s1 7 al-sufawi 5.752 4.8 c4-s1 8 alfarise 5.404 4.5 c4-s1 9 sallah 2.870 2.5 c4-s1 10 anssab 0.115 1.5 c1-s1 11 fatema 4.53 2.6 c4-s1 na , ca ++ , mg ++ , and sar in (epm) (suares,1981) al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 74 table (5): water quality for livestock and poultry usages (ayers,1994) rem. rating ec (ds/m) usable for all classes of livestock and poultry excellent <1.5 usable for all classes of livestock and poultry. may cause temporary diarrhoea in livestock not accustomed to such water; watery droppings in poultry. very satisfactory 1.5-5.0 may cause temporary diarrhoea or be refused at first by animals not accustomed to such water. satisfactory for livestock 5.0-8.0 often causes watery faeces, increased mortality and decreased growth, especially in turkeys. unfit for poultry usable with reasonable safety for dairy and beef cattle, sheep, swine and horses. avoid use for pregnant or lactating animals. limited use for livestock 8.0-11.0 not acceptable for poultry. unfit for poultry unfit for poultry and probably unfit for swine. considerable risk in using for pregnant or lactating cows, horses or sheep, or for the young of these species. in general, use should be avoided although older ruminants, horses, poultry and swine may subsist on waters such as these under certain conditions. very limited use 11.0-16.0 risks with such highly saline water are so great that it cannot be recommended for use under any conditions. not recommended >16.0 table (6): water quality standard for industrial usages(hem 1991) oil industrial cement factory parameters 75 ---ca ++ (mg/l) 30 ----mg ++ (mg/l) 300 250 cl (mg/l) ---250 so4 -2 (mg/l) 6 -9 6.5 -8.5 ph 350 -----t.h (mg/l) table (7): wells that satisfies standard limitations for industrial usages. t.h (mg/l) ph so4 -2 (mg/l) cl (mg/l) ca ++ (mg/l) mg ++ (mg/l) industrial -----all 10,11 1,6,8,9,10 -------------------cement no one all 10,11 all all 6,9,10 oil table (8): water quality for building usages (al-manmi 2008). parameters ca ++ mg ++ na + cl so4 -2 hco3 permissible limit (mg/l) 437 271 1160 2187 1460 350 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 70 concentration of ca for investigated wells 0 100 200 300 400 500 600 700 800 1 2 3 4 5 6 7 8 9 10 11 no. of well ca(mg/l) ca (mg/l) who idws (136) (-30)(70)(70)(67)(112)(144)(87) (-130)(-44)(118) figure (2): concentration of ca and elevation of excavation w.c.t sea level (m). figure (1): locations of wells in physiogarghic zone (sadiq 2013) al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 72 concentration of mg for investgated wells 0 50 100 150 200 250 300 350 400 1 2 3 4 5 6 7 8 9 10 11 no. of well mg(mg/l) mg mg/l who idws (136) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (3): concentration of mg and elevation of excavation w.c.t sea level (m). concentration of na for investigated wells 0 100 200 300 400 500 600 1 2 3 4 5 6 7 8 9 10 11 no. of well na(mg/l) na mg/l who idws (136) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (4): concentration of na and elevation of excavation w.c.t sea level (m). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 77 concentration of cl for investigated wells 0 50 100 150 200 250 300 350 400 1 2 3 4 5 6 7 8 9 10 11 no. of wells cl(mg/l) cl (mg/l) who limitations idws (136) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (5): concentration of cl and elevation of excavation w.c.t sea level (m). concentration of so4 for investigated wells 0 200 400 600 800 1000 1200 1400 1 2 3 4 5 6 7 8 9 10 11 no. of wells so4(mg/l ) so4 mg/l who idws (136 ) (-30)(70)(70)(67)(118)(112 ) (144 ) (87) (-130)(-44) figure (6): concentration of so4 and elevation of excavation w.c.t sea level (m). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 70 concentration of t.h. for investigated wells 0 500 1000 1500 2000 2500 3000 1 2 3 4 5 6 7 8 9 10 11 no. of well t.h.(mg/l) t.h mg/l idws (136) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (7): concentration of t.h. and elevation of excavation w.c.t sea level (m). concentration of t.d.s. for investigated wells 0 500 1000 1500 2000 2500 3000 3500 4000 4500 1 2 3 4 5 6 7 8 9 10 11 no. of well tds(mg/l) t.d.s mg/l who idws (136) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (8): concentration of t.d.s. and elevation of excavation w.c.t sea level (m). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 77 ph value for investegated wells 5 5.5 6 6.5 7 7.5 8 8.5 9 1 2 3 4 5 6 7 8 9 10 11 no. of well ph ph value who-idws who-idws (136 ) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (9): value of ph and elevation of excavation w.c.t sea level (m). turbidity of wells 0 50 100 150 200 250 300 1 2 3 4 5 6 7 8 9 10 11 no. of wells ntu turbidity ntu who (136) (-30)(70)(70)(67)(118)(112)(144)(87) (-130)(-44) figure (10): value of turbidity and elevation of excavation w.c.t sea level (m). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 77 250 250 750 750 2250 2250 5000 5000 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 10 100 1000 10000 ec(μs/cm) c2-s4 c1-s1 c1-s2 c1-s3 c1-s4 c2-s3 c2-s2 c2-s1 c3-s4 c3-s3 c3-s2 c3-s1 c4-s4 c4-s3 c4-s2 c4-s1 dangerous of salinity low medium high veryhigh d a n g er o u s o f n a lo w m ed iu m h ig h c1, c2, c3 and c4 meanes low, medium, high, and veryhigh dangerous of salinity respectively s1, s2, s3 and s4 meanes low, medium, high, and veryhigh dangerous of na respectively figure (11): classification of irrigation water according to usa salinity lab. (lamaddalena 1997). template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 352 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. synthesis and characterization of new alkyd resins obtained from bitter almond oil and cocoanut oil as binder for surface coating mohammed ail mutar, department of chemical engineering, college of engineering , university of al-qadisiyah .e mail: mohammed.ail@qu.edu.iq noor mohammed abdul hassan, department of chemistry , college of education, university of al-qadisiyah e mail: nm045744@gmail.com received on 8 jonuary 2016 accepted on 9 august 2017 abstract: alkyd resins constitute a very high proportion of conventional binders used in surface coating . a new alkyd resins were synthesized by reacting ( bitter almond oil or coconut oil with propylene glycol or ethylene glycol and phthalic anhydride) in the presence of lead oxide as a catalyst. synthesis of alkyd resins, two stages were involved. at the first stage, bitter almond oil or coconut oil was converted to monoglycerides as a polyol by alcoholysis. esterification process was held at the second stage by adding phthalic anhydride and xylene in the mixture. three different alkyd resins have been synthesized (short , medium and long) from bitter almond oil or coconut oil by using different ratios of phthalic anhydride .the various physic-chemical properties of alkyd resins like acid value , saponification value , iodine value density, viscosity, chemical resistance and volatile matter were studied . the resulted alkyd resins are readily soluble in aprotic polar solvents , such as (toluene , acetone , benzene , xylene , dmf, dmso , methanol and ethanol ) without need for heating. thermal analysis of alkyd resins by thermo gravimetric analysis (tga) and thermal differential calorimeter (dsc) techniques. reveals that these aromatic alkyd resins possess thermal stability. alkyd resins were characterized by (ftir and 1h-nmr) spectroscopies . keywords: alkyd, bitter almond oil, coconut oil , paint, binder introduction paints may possibly be described as a colloidal combination of chemical ingredients, when diffused on a surface in a thin layer they form a dense, consistent and adherent layer. they are used regularly in our life for ornamental purposes, and for preventing surfaces of being affected by different environmental influence as uv-radiation, chemical invasion and mechanical stresses. a binder, pigment, solvent, and additives are common ingredients of paint. the polymer-binding material (alkyd resin) is responsible in addition to wide range of variations for finding a continuous layer that adheres to the lower layers and binds other ingredients together (1) . coating material through using polyester or alkyd is commonly employed for surface covering as binders, adhesives and plasticizers. what is interesting about alkyd is that it is the lowest materials in mailto:mohammed.ail.@qu.edu.iq mailto:nm045744@gmail.com al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 353 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. cost if compared with other coating materials and it is subject to give a covering that shows less layer faults during applications. also, stability of alkyd layers, particularly for outdoors use, tends to be poorer than films, i.e., acrylics and polyurethanes (2,3). however, one of the factors affecting coating film properties is the type of fatty acid or oil used in the alkyd production (4,5) . various types of oil can result in differences in film properties . the preparation of alkyd resins can be achieved by condensation polymerization of a polyhydric alcohol (e.g. glycerol ) and polyfunctional acid or polybasic acids (e.g. phthalic anhydride and isophthalic acid) changed by oily acid or their triglyceride. the alkyd resins manufactured this way are known as oilmodified alkyd resins and form 70% of the common binders used in external coating (6). they define the performance quality of surface coatings such as the degree of drying, gloss, stability of the dry layer and resistance of the dry layer to scratch and chemicals . however, categorizing of alkyd resins is centered on the oil length and oil type (7) the vegetable oils, which used in oil-modified alkyd resins are typically extracted either by a mechanical press or solvent extraction(8) . the natural oil in the oil-modified alkyds reacts with atmospheric oxygen, which leads to the formation of a network of polymers cross-linked through the (c=c) bond. the oil oxidative drying brings about the formation of a layer that displays enhanced characteristics with drying time, hardness or water resistance(9). alkyd resins have gained high significance due to their economy, availability of raw materials, durability, biodegradability, , good adhesion, flexibility and ease of application .in this work, two alkyd resin (ar1-ar2) have been synthesized in high yield by polycondensation between dicarboxlic acid and polyols with oils using lead oxide as catalyst . qualitative structure analysis of the polymers have been carried out by the using of ft-ir, and 1h-nmr spectroscopy, thermal stability were systematically investigated . 1. objective of study 1the objective of the study is to produce different types of alkyd resins containing the ester group obtain high adhesion and dehydration without the addition of a dry material and high elasticity compared to alkyd resins used in the market and then used in the manufacture of dyes. 2alkyd resins are prepared by reacting vegetable oils or fatty acids with multiple carboxylic acid (anhydrous phthalic acid), hydroxyl hydrolyses ( propylene glycol, triethanolamine etc) with catalysts such as lead oxide. 3 study and diagnosis of polymers prepared spectrally by the techniques of (ftir, 1h-nmr ) 4studying and evaluating the thermal stability of the prepared polymers through two thermal analysis techniques (tga) and differential thermal analysis (dsc). 5study the solubility of polymers prepared in a range of different organic solvents. . 2. experimental 2-1 materials bitter almond oil (c14h14o2) , cocoanut oil (c41h72o6 ) , phthalicanhydride (c8h4o3) , lead oxide (pb0) , xylene(c6h4(ch3)2 , all from made in (merck) ; propylene glycol (c3h6(oh)2, ethanediol (c2h6o2), ethanol (c2h5oh),all from made in (scharlab s.l) ; tetrahydrofurane (thf)( c4h8o),dimethyl sulphoxide (dmso)(ch3)2so ,all from (merck) ; methanol(ch3oh), acetone(c3h6o), toluene(c7h8), carbon tetrachloride( ccl4), all form (bdh-chemicals) ; sulfuric acid(h2so4) form (sd fine-chem) ;hydrochloric acid(hcl) , sodium chloride(nacl) , all form (hi-media) ; potassium hydroxide(koh) , potassium iodide(ki), sodium thiosulfate(na2s3o3) all from (himedia) . instruments ftir 8400s , fourier transform infrared spectrophotometer , shimadzu, japan), ( oven ,trivp international crop .italy) ,( hot plate stir , bibby strlintd .uk) (measurement of 1 hnmr spectra : recorded nmr spectra using a type of bruker ,ultra shield 300 mhz, switzerl and using (dmso-d6 ) as a solvent at the university's educational teacher-tehran iran) ,(thermogravimetry analysis (tga) were performed on a al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 354 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. polymer laboratories co england, model pl-tg at iran polymer & petrochemical institute , using a heating rate of 10ºc/min in argon atmosphere within the temperature range of 25-800ºc)(differential thermal analysis (dsc) measurement using apparatus (dsc) type (dsc 131 evo, setaram) is the origin (france) in the department of chemistry / faculty of education / university of qadisiyah ), ( viscosity device the use of viscosity measurement device for measuring the viscosity of the alkyd resin models record in the department of chemistry / faculty of education / university of qadisiyah / by a device from a company (brookfield) type (rvdvii + p 8500), (230 v~) and frequency (50/60 hz) and strongly (30 va). the machine is manufactured in (u.s.a) . 2-2synthesis of alkyd resin two stages preparation alkyd resins (10) : stage 1 (alcoholysis): in this stage, monoglyceride was first prepared by reacting (bitter almond oil with propylene glycol or coconut oil with ethanediol), then added pbo as a catalyst. in alcoholysis reaction, the oil was heated with an agitation speed of (700 rpm) and n2 sparging rate of about (0.06ft3/sec) to 230240°c. alcohol and selected catalyst were added and alcoholysis reaction was carried out at 230-240°c.the reaction of the mixture continued till the sample of the reaction mix became solvable in two to four volumes of anhydrous methanol. after completing alcoholysis reaction, the reaction mixture was cooled to 140°c. stage 2 (esterification): in this stage, phthalic anhydride was added to the monoglyceride mixture. the temperature was maintained at the range of 230-240°c and maintained at this temperature. the leakage amount of n2 was increased to (0.1ft3/sec). the reaction was observed by intermittent determination of the acid value of the mixture till acid value fell to nearly (9) . table (1) shows the proportions of the chemicals used in the reaction long medium short raw material 60-70 % 45-60 % 25-40 % bitter almond oil or cocoanut oil 20-30 gm 30-35 gm 35 < gm phthalic anhydride 14.6 gm 14.6 gm 14.6 gm glycerol 0.4 gm 0.4 gm 0.4 gm lead oxide 60 ml 60 ml 60 ml xylene 2-3physico – chemical tests 2-3-1acid value test (11) acid value was determined according aoac method and to standard 969.17 1997 2-3-2drying test aluminum plates were cleaned by ethanol to make sure that there are no contaminants present to affect the result . a hand coater with different fixed thickness was used to evenly coat the resin on the surface of the testing plates (12) . 2-3-3saponification number test weight (1 gm) of sample into an erlenmyer flask , in pipette 25 ml of (0.5 n) koh put in the flask ,then add 4 ml of the solvent (ethanol-ether) to the flask , then reflux for (30) minutes, rinse the inside of the condensers with about (25) ml di water allow the solvent to drain into the erlenmeyer flask , and allow the solution to cool to room temperature , then add three to five drops of phenolphthalein indicator to the solution with moderate agitation , then add (0.5) hcl (titrant) to the burette , and not level , then add titrant from the al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 355 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. burette to the solution until the faint pink color permanently (for at least thirty seconds ) disappears, and not level of titrant in the burette (13) . 2-3-4iodine number test deliver ( 0.1) g sample to (300) ml conical flask with ground in stopper. add 20 ml carbon tetrachloride and seal. dissolve sample in an ultrasonic washing machine , then add 25 ml hanus solution, and seal. shake for one minute , then keep it sealed and leave in a dark room (about 20 ºc) for 30 minutes , then add (10) ml of 15% potassium iodide and 100 ml water , and seal. shake for (30) seconds, then titrate with (0.1) mol / l sodium thiosulfate to obtain iodine value then also perform blank test to obtain blank level (14) . 2-3-5density test the density was determined according to nf en 1097-6 using analytical scale and pycnometer s9611826 (100 ccs) (15) . 2-3-6viscosity test rookfield rotary viscometer ku-2 model rvdv-ii+ p8500 was used to measure the viscosity at 25 ºc, and using different spindle and speed (16) . 2-3-7volatile matter test three specimens were placed in the oven within (30) min after preparation of alkyd resin in previously weighed watch glass and heated for (2 h) at (135-140) ºc . the nonvolatile matter was calculated from the difference in initial and final weights of the watch glass . the mean value of the three results was reported as the percentage nonvolatile matter . figure (1) structure of polymer (ar1) figure (2) structure of polymer (ar2) 3result and discussion 3-1synthesis and characterization of polymers prepared 3-1-1synthesis and characterization of (ar1) this polymer was synthesized by the condensation of bitter almond oil with propylene glycol and phthalic anhydride (17) in the presence of lead oxide as catalyst and temperature is (120-240 c º) for (6 hours) according to the equation in the reaction scheme (1) . alkyd resin bitter alomand oil ch3-ch-ch2-o o-ch2-ch-ch3 o=c c=o c=o c=o alkyd resin c=o c=o o=co oc=o ch2-ch2-o o-ch2-ch2 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 356 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. scheme (1) synthesis of (ar1) characterization of (ar1) ft-ir spectrum : the ftir spectra of (ar1) as show in (figure 3) which indicates absorption band of (oh) carboxylic at (3505 cm-1) ,(c-h) aromatic at (3002 cm-1) , (c-h) aliphatic at (2854, 2923 cm-1), (c=o) in the ester group at (1745 cm-1) , (c=c) aromatic at (1475 cm-1) , and (c-o) at (1220 cm-1) . ( 1 h-nmr) spectrum of (ar1) , is shown in (figure 4) assigns the following chemical shifts ; (= 1.151.44 ppm) for methyl group, (= 1.89-1.96 ppm) for (ch2) , (= 5.19-5.30 ppm) for (oh)in bitter almond oil, (= 2.5 ppm) for (dmso), (= 2.49 ppm)for (h2o),  = 7.67 ppm) for ar-h group . ch2-o-cor r-cooch ch2-o-cor 1) alcoholysis stage : bitter alomand oil + 2 oh propylene glycol r-ococh pbo / n2 120c ch3 ch2-oh monoglyceride 2) esterification stage monoglyceride + o o o phthalicanhydride 240c + h2o alkyd resin r= bitter alomand oil ch3-ch-ch2-oh 0 0 or ch3 ch2-oh r-ococh r-ococh ch3 ch2-oh xylene ch3-ch-ch2-o o-ch2-ch-ch3 o=c c=o ocor ocor al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 357 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3) : ftir spectra of (ar1) figure (4) 1hnmr spectra of (ar1) 3-1-2synthesis and characterization of (ar2) this polymer was synthesized by condensation of cocoanut oil with ethanediol phthalic anhydride in the presence of lead oxide as catalyst and temperature is (120-240 c º) for (6 hours) according to the equation in the reaction scheme (2) . alkyd resin bitter alomand oil ch3-ch-ch2-o o-ch2-ch-ch3 o=c c=o c=o c=o al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 358 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. scheme (2) synthesis of (ar2) characterization of (ar2) ft-ir spectrum : the ftir spectra of (ar2) as show in (figure 5) which indicates absorption band of (c-h) aromatic at (3100 cm-1), (c-h) aliphatic at (2854, 2923 cm-1) , (c=o) in the ester group at (1681 cm-1) , (c=c) aromatic at (1445 cm-1) , and (c-o) at (1300 cm-1). ( 1 h-nmr) spectrum of (ar1) , is shown in ( figure 6) assigns the following chemical shifts ; (= 3.643.67 ppm) for methyl group, (= 4.21-4.23 ppm) for (och2) , (= 2.5 ppm) for (dmso), (= 3.39 ppm)for (h2o), (= 7.58-7.67 ppm) for ar-h group . 1) alcoholysis stage : monoglyceride 2) esterification stage monoglyceride + o o o phthalicanhydride 240c + h2o alkyd resin 0 xylene ch2-ch2-o o-ch2-ch2 o=c c=o ocor ocor 2 ch2-o-cor r-cooch ch2-o-cor coconut oil + 2 ch2 oh ch2 oh ethylene glycol ( ethane diol) pbo/n 2 120c ch2-oh 0 ch2-ocor or ch2-ocor ch2-oh ch2-oh ch2-ocor r= coconut oil al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 359 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (5) ftir spectra (ar2) figure (6) 1hnmr of (ar2) 3-2physico – chemical tests 3-2-1acid value test the acid value (av) is the mass of potassium hydroxide (koh) in milligrams that is required to neutralize one gram of chemical substance. the acid number is a measure of the amount of carboxylic acid groups in a chemical compound, such as a fatty acid (18) . it has been observed from the results shown in the alkyd resin c=o c=o o=co oc=o ch2-ch2-o o-ch2-ch2 alkyd resin c=o c=o o=co oc=o ch2-ch2-o o-ch2-ch2 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 360 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (table 2), (ar2) prepared from cocoanut oil showed an acid value higher than the (ar1) prepared from bitter almond oil due to the length of the fatty acid chain component there of resin cocoanut oil, containing (c41) carbon atom and bitter almond oil containing ( c14) . table (2) shows the values acidity of alkyd resins prepared acidity alkyd resins long medium short 75.7 7.29 7.01 ar1 75.7 75.. 8.41 ar2 3-2-2iodine number test the value of iodine in chemistry is calculated through the mass of iodine in grams, which is used by 100 grams of a chemical substance. the numbers of iodine are regularly employed to define the extent of unsaturation in oily acids. this unsaturation takes the form of double bonds that reacted with iodine compounds. the higher the iodine number, the more c=c bonds are present in the fat (note that the number of iodine saturated fatty acids equals zero). as well as the number of iodine used in the to detect adulterated vegetable oils with oils constants. whenever a high iodine number, i.e. it contains high proportion of unsaturated fatty acid and iodine number and if iodine number is low, i.e. fatty acids is saturated (19). the results of the prepared resins observed through the ( table 3), the iodine value is higher in (ar2) prepared from cocoanut oil showed an acid value higher than the (ar1) prepared from bitter almond oil due to the length of the fatty acid chain component there of resin cocoanut oil, containing (c41) carbon atom and bitter almond oil containing ( c14) . table (3) shows the values iodine number of alkyd resins prepared iodine number alkyd resins long medium short .. .7 011 ar1 0 77 011 041 ar2 3-2-3saponification value test saponification value represents the number of milligrams of potassium hydroxide required to saponify (1g) of fat under the conditions specified. this is to measure the average molecular weight of all the fatty acids presented in this process. most of mass of fat /tri-ester is in the three fatty acids, it permits for comparison of the average fatty acid length chain. the long chain of fatty acids, which are found in fats have low saponification value due to their relative fewer number of carboxylic functional groups for each mass unit of the fat when compared to short chain fatty acids (20) . the results were observed from the ( table 4) showed (ar2) prepared from cocoanut oil (c41) less saponification value than (ar1) prepared from vegetable oil short-chain bitter almond oil (c14) because of the saponification number proportional inversely to the length of chain fatty acid . al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 361 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (4) shows the values saponification number of alkyd resins prepared saponification alkyd resins long med. short 7.7 7.7 7.1 ar1 07. 0.7 0.. ar2 3-2-4density test a substance density and the volumetric mass density is its mass per unit volume. mostly used symbol for density is ρ. and depends on temperature and pressure . the results were observed for the resins prepared in the ( table 5), the density is less of alkyd resin increasing fatty acid chain length and vice versa, also due to the presence of a relatively less number of active carboxyl groups . is observed (ar2) prepared from cocoanut oil (c41) showed the density is less than (ar1) prepared from vegetable oil shortchain bitter almond oil (c14) because of the saponification number proportional inversely to the length of chain fatty acid . table (5) shows the values density of resins density alkyd resins long med. short 15.7. 15.11 15.1. ar1 157.1 157.7 15714 ar2 3-2-5drying test drying rate of alkyd resin based on bitter almond oil or cocoanut oil of diverse applied thickness and employed certain amount of cobalt. these oils categorized as non-drying oil that contain fatty acid higher proportion in saturated chains than other types of oil. non-drying oil alkyds do not produce layer without alteration (21) . however, alteration and addition of driers provide resins the form of film at regular atmospheric circumstance. denser layers (120 µm) are in need for much more time to dry in comparison with thinner layers (30 µm).the thicker films drying mechanism necessitate a great deal of cobalt to cross-link between chains. when the catalyst concentration decreased, a less dense cross-linked network was formed. the thicker films alkyd drying time can radically increase the oxygen uptake either at the double bond or methylene group as the increasing presence of driers (22). it was noted that the resin ability to air dry is because phthalic anhydride modification in specific amount and drier that leads to resin to cross link. the higher the presence of phthalic anhydride and the driers, the longer chain length and a higher cross linked dense resin through condensation polymerization. the resin turns to be denser, viscous and more compact conferring self-curing feature. the results were observed from the ( table 6) showed higher oil content in long oil and medium oil alkyds gave slower initial drying , due to more thermosetting of long oil alkyd as compared to short oil alkyd. subsequently, better thorough drying can be assigned to same thermosetting nature of oil present in long oil alkyd. short oil alkyd thus has slower thorough drying due to less oil present . table (6) shows the values drying time of resins drying time alkyd resins long med. short 20 min 15 min min01 ar1 33 min 25 min 20 min ar2 al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 362 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3-2-6viscosity test the viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress . for liquids, it corresponds to the informal concept of "thickness" .the viscosity of the solution is an important tool for characterization polymers are a measure of molecular weight of polymer as the viscosity of the solution is a measure of the size. the factors affecting viscosity: a) pressure: pressure viscosity little importance but viscosity effect appears when the pressure increases (68 bar). b) temperature: when temperatures decrease viscosity because at high temperature of liquid increase distances between molecules less friction and therefore less viscous.it is noted that the viscosity resins alkyd increases during reaction for all types of oils used in manufacturing, and also notes that the viscosity increase slowly during the hours (2-3) interaction. then, it increases viscosity significantly in esterification reaction between mono glyceride and phthalic anhydride however after 5 or 6 hours ends interact very viscous alkyd resin consists of any strings are a gelatinous substance polymer (gelatin) (23). c) the viscosity is highly dependent on amount of cross-linking in polymer. it was noted by the results shown in (table 7), showed (ar1) prepared from cocoanut oil (c41) higher viscosity than (ar2) prepared from vegetable oil short-chain bitter almond (c14) because of the viscosity proportional inversely to the length of chain fatty acid . table (7) shows the viscosity values of prepared resins temper. no. spindle speed long medium short alkyd resin 25 . 011 011 0.1 071 ar1 41 41 .1 ar2 3-2-7volatility matter test it was noted by the results shown in (table 8), where the difference in the value of the volatility between each resin prepared (ar1) showed less value volatility due to the short chain fatty acid (bitter almond oil) while (ar2) showed a high value volatility due to length chain fatty acid cocoanut oil container in structure on the double bonds of the ability to interact with oxygen therefore volatility quickly . table (8) shows the values volatility of resins volatility alkyd resins 41% ar1 71% ar2 3-2-8chemical resistance test the resistance of alkyd resins prepared for some chemicals was tested. the results indicated in (table 9) show the difference in chemical resistance between each resin. the ar1 and ar2 resin prepared from bitter almond oil and coconut respectively are resistant (insoluble) in water because the resin is made up of a chain of unsaturated fatty acid, i.e., non-polar organic compounds and water is a polar solvent. while al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 363 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. it is not resistant to any (dissolved) in the solvent tetrahydrofuran (thf) because it is a non-polar organic solvent. the ar2 resin is also noted. the record of coconut oil is non-resistant (dissolved) in hydrochloric acid, sulfuric acid, sodium hydroxide and sodium chloride. while resin (ar1) is resistant to solvents above due to the different type of vegetable oils manufactured by alkyd resin according to their nature and their resistance to solvents. table (9) shows the chemical resistance values of prepared resins distilled water hcl h2so4 koh nacl thf alkyd resin _ + + + + _ ar1 _ _ _ _ _ _ ar2 3-2-9solubility test alkyd resins showed high solubility in different type of solvents .( table 10) described solubility of samples, was measured by taking the solubility (0.01 g) of the sample prepared resin and melted in (2 ml) of the solvent, the solvents used include (dmf, acetone, toluene, xylene,) (polar aprotic) non-polar solvents such as (benzene, chcl3) and other solvents such as methanol, ethanol. the solvent molecules increase with the distance between the molecular chains of the resin. the spaces between long chains with pendant side group of resin are invaded by solvent molecules as they fill the space made available by chain movements. when movements bring two chains close to proximity, short range attractive forces are therefore established resulting in restricted chain movement and thus the formation of a viscous system (24 ,25). solvent are added to deal with the problem of high viscous resin which is an obstacle in substrates wet ability . table (10) shows the solubility of alkyd resins alkyd resin solvent xylene dmf toluene acetone dmso benzene methanol ethanol ar1 + + + + + + + + ar2 + + + + + + + + + soluble at room temperature , +partially soluble 3-3thermo gravimetric analysis (tga) study thermo gravimetric analysis (tga) involves determining changes in mass as a function of temperature . it is commonly used to search degradation temperatures, absorbed content of materials, levels of inorganic and organic parts contained in a material and analysis solvent residues (26) . it employs a sensitive electronic balance from which the sample is suspended in a furnace controlled by a temperature programmer . the thermal properties of two samples of these alkyd resins were investigated by means of thermo gravimetric analysis (tga) in argon atmosphere at heating rate of 10 ºc/ min . the results such as ti , top , tf , t50% , % residue at 300 ºc , and char yields at 200 ºc are summarized in (table11) and (curve 7,8) . the temperatures of 50% weight loss of (ar1 , ar2) as a standard indication for thermal stability of polymers were all from 300 ºc, the char yields of (ar1) are 50% and (ar2) are 98% at 200 ºc in argon atmosphere (27) , which indicate they could meet temperature resistant requirements, which can be used in surface coating application . weight residue of (ar1) are 20% and (ar2) are 65% at 300 ºc . al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 364 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table (11) some properties of the thermal stability of the curves of thermal analysis (tga) alkyd resin dt/°c t50% residue at oc300 char % at 200°c ti top1 top2 tf ar1 260 200 288 >300 288 65 98 ar2 200 150 250 >300 295 20 50 dt : decomposition temperature.درجة حرارة التفكك ti : initial decomposition temperature. التفكك االبتدائية درجة حرارة top : optimum decomposition temperature.درجة حرارة التفكك المثلى tf : final decomposition temperature.درجة حرارة التفكك النهائية t50% : temperature of 50% weight loss, obtained from tga % من 1.ليمر درجة حرارة التفكك عند فقدان البو وزنة char% at 200°c : residual weight percentage at 200°c in argon by tga5 النسبة المئوية لتفحم العينة عند درجة figure (7) tga cure of ar1 3-4differential scanning calorimeter analysis (dsc) study differential scanning calorimetry,is a technique of thermal analysis that investigates how material’s heat capacity (cp) is transformed by temperature. a known mass sample is heated or cooled and the variations in its heat capacity are observed as alterations in the heat flow. this allows to reveal transitions such as melts glass transitions (tg), and the melting point (tm) the degree of crystallization (tc) (28) . this test was applied to the prepared samples , shows the(table 12)and (curve 9) for the sample came from reaction bitter almond oil with propylene glycol the results showed the value of the glass transition (tg) of the mixture (35c º), referring to obtain the flow temperature and then increases endothermic the sample to reach the melting point (tm) at (295 c º) . it also shows a (curve 10) for the sample came from reaction cocoanut oil with ethanediol and the results showed the value of the glass transition (tg) of the combination (36.4cº) referring to an increase in the flow temperature and then increase endothermic the sample to reach the al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 365 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. melting point (tm) at (297 c º) completely dissolve and then less the sample heat absorption rate and by a curved appointed degree of crystallization (tc) of the mixture was (85.1 cº). figure (8) tga cure of ar2 table 12: shows the degree of glass transition, melting point and the degree of crystallization in the differential thermal analysis tc (cº) tm (cº) tg (cº) samples 0..50 295 35 ar1 85.1 297 36.4 ar2 tg : degree glass transition , tm : melting point , tc : degree of crystallization figure (9) dsc cure of (ar1) al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 366 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (10) dsc cure of (ar2) conclusions in this work, new alkyd resin used in many industries like paints and surface coatings because of their properties such as friction resistance, humidity, scalability high adhesion, high dry without addition a drying agent, and high flexibility. and it shows that through the study of their properties such as drying times, the volatility, saponification number, iodine number, acid value, and density of these resins all of the tests depends on the fatty acid chain length or type of vegetable oil used in the manufacture of these resins. alkyd resins show high solubility in various solvents because their structures contain chemical groups such as (hydroxide, and links ethers) alkyd resins showed curves thermal gravimetric analysis (tga) high increase in thermal stability because of the different types of vegetable oils used in alkyd resins industry and structural diversity of the structures of the new alkyd resins. references 1wicks , z. w., jones, f.n., & paappas, s.p. (1994). organic coatings : science and technologe vol. 1., john wiley & sons . 2zeno, w.w.,frank, n.j. and peter, s.p., organic coatings science & technology, 2nd ed., wiley – interscience, pp.135 and pp.142(1996). 3kim, d. and kim, s.w., ,,barrier property and morphology of polypropylene / pol-yamide blend film,, korean j. chem. eng., 20,776 (2003). 4kabasakal, o.s., guner, f.s., erciyes, a.t. and yagci, y., ,,styrenation of oils based on secondary esters of caster oil,,, j. coating technol., 67,47 (1995) . 5kabasakal, o.s., guner, f.s., arslan, a., ergan, a., erciyes, a.t. and yagci, y., ,,use of caster oil in the preparation of various oil-based binders,, j. coating technol., 68,57 (1996) . 6bajpai, m., & seth, s. (2000) . use of unconventional oils in surface coating blends of alkyd resins with epoxy esters. pigment resins technol., 29,82-87. http://dx.doi.org/ 10. 1108/03699420010317825 . 7micciche, f. (2005). the combination of ascorbic acid derivative/iron salts as catalyst for the oxidative drying of alkyd-paints : a biomimetic approach. technische universiteit eindhoven. http ://alexandria.tue.nl/extra2/200512801.pdf al-qadisiyah journal for engineering sciences vol. 10 , no. 3 issn: 1998-4456 page 367 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 8abulude, f.o., ogunkoya, m.o., & ogunleye, r.f. (2007). storage properties of oils of two nigeria oil seeds jatropha curcas (physic nut) and helianthus annuus. amer. j. food tech., 2, 207-211. http://dx.doi.org/10.3923/ajft.2007.207. 211 . 9akintayo, c.o. (2004). synthesis and characterization of aibizia benth medium oil modification of alkyd resin and its chemically modified derivatives. phd thesis . university of ibadan, nigeria. 10ogunniyi d.s. & odetoye t.e, preparation and evaluation of seed oil –modified alkyd resins, biores technol, 99. pg: 1300-1304,(2008). 11 ceirwyn s. j., analytical chemistry of foods, blackie academic and professional, chapman and hall, london, (1995) . 12 r. s. abiev, i. v. lavretsov, chem. eng. sci., pg:74, 59– 68. http://dx.doi.org/10.1016/j.ces.2012.02.024, (2012). 13a.o.a.c. 17th edn, official method 920. 160saponification number of oils and fats / iupac 2. 202 /i.s.i. handbook of food analysis (part xiii) – 1984, page 78,(2000) . 14a.o.a.c. 17th edn, official method 920. 159iodine absorption number of oils and fats / i.s.i. handbook of food analysis (part xiii) – 1984, page 76,(2000) . 15density definition in oil gas glossary". oilgasglossary.com. retrieved -09-14 pg: 18-19, (2010). 16 m.i. ojovan, k.p. travis and r.j. hand "thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships". j. phys.: condensed matter 19 (41): 415107. doi:10.1088/09538984/19/41/415107. pg: 237,(2000). 17rahimi, a. and farhangzadeh, s. "kinetics study of bisphenol a synthesis by condensation reaction", iranian polymer journal. 10 (1) : 29–32 pg: 38-39,(2001). 18 i.si. handbook of food analysis (part xiii)-1984 page 67/ iupac 2.201/ i.s: 548 (part 1) – 1964, methods of sampling and test for oils and fats / iso 660:1996 determination of acid value and aciditypp:428-430, (1979). 19a.o.a.c. 17th edn, official method 920. 159iodine absorption number of oils and fats / i.s.i. handbook of food analysis (part xiii) – 1984, page 76 (2000). 20 multon j. l., analysis of food constituents, wiley-vch, new,york pg: 16, (1997) . 21issam a.m., cheun c.y., (2009). a study of the effect of oils on the properties of a new alkyd resin. malaysian polymer journal, 4(1), 42-49. 22akintayo, c.o., and adebowale, k.o., (2004), syntheses characterization and evaluation of chlorinated albizia benth medium oil alkyds, progress in organic coatings. 2 pp 138-143. 23glenn elert. "the physics hypertextbook-viscosity" (http://physics.info/viscosity/). physics.info. . retrieved -09-14 pg:24 (2010). 24boxall ,j. and von fraunhofer, j.a., (1977). concise paint technology, elek science london . 25boxall ,j. and von fraunhofer, j.a., (1980). concise paint formulation, principleand practice, george godwin limited london . 26andrey tarasov.” thermal analysis: methods, principles,applicason.” lecture on thermal analysis 26.16.pg: 76,(2012). 27k. b. cantre, j. h. martin and k. s. ro " application of thermogravimetric analysis for the proximate analysis of livestock wastes", journal of astm international. 7 (3)pg:2-13(2009). 28bernhard wunderlich . thermal analysis, text for an audio course. athas, advanced thermal analysis, alaboratory for research and instruction (1981 ) al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 the effect of fins geometry on longitudinal trihedron cylinder forced convection heat transfer coefficient dr.abbas jassem jubear, department of mechanical engineering, university of wassit, email:abbaskut72@yahoo.com.au received 30 october 2014 accepted 13 january 2015 abstract this study aims to perform an experimental study of heat transfer by forced convection for three cylinders (with 12 triangular, rectangular shape fins and without fins) made of aluminum. the inner and outer diameters of these cylinders considered in this study ware (16 mm) and (48 mm) respectively .the study has been performed for different,geometry, slope angles ( ) and range of air velocities (0.5-4m/s). the three cylinders ware heated by a constant heat flux generated by passing an alternative current (ac) through a resistance placed inside the internal space for each cylinder . the effects of air velocity , inclined angle and geometry of fins have been studied in this study for a range of heat fluxs (13-247) w. the results show that the rate of heat transfer increases as the air velocity increases but it decreases with increasing inclined angle. the heat transfer coefficient increases generally with increasing reynolds number (re) and the heat transferred from triangular test sample (12) fins is greater than that from rectangular test sample and without fin type. an empirical relationships between reynolds number (re) and nusselt number (nu) is concluded:  test sample (12) fins with triangular section :  test sample (12) fins with rectangular section:  test sample without fins keywords: fins, force convection, heat transfer, fin tube, fin geometry. السطوانة مزعنفة طولي انتقال الحرارة ألقسريتاثير شكل الزعانف على معامل الخالصة المقطع يهدف البحث الحالي إلى إجراء دراسة عملية النتقال الحرارة بالحمل ألقسري من اسطوانة ذات زعانف طولية مستطيلة 4 5.0واسطوانة ذات زعانف طولية مثلثة المقطع واسطوانة بدون زعانف مصنوعة من األلمنيوم ولمدى سرع مختلفة ) م/ثا(.ولمستوى فيض حراري ثابت وذلك بإمرار تيار كهربائي متناوب خالل مقاومة مثبتة داخل الحيز الداخلي لكل اسطوانة. تم استعمل في هذه الدراسة نموذج االسطوانة المزعنفة . )وايا ميل مختلفة عن األفق وضع النموذج المستطيل المقطع بز ملم( , وتمت دراسة تأثير كل من سرعة الهواء 44ملم( وبقطر خارجي مع الزعنفة مقداره ) 61) طوليا بقطر داخلي مقداره كمية الحرارة ان توصلت الدراسة إلى. ( واط742-4..6فيض تراوحت بين ) وزاوية الميل والشكل الهندسي للزعانف ولمعدالت كمية الحرارة المنتقلة بزيادة زاوية الميل عن في نقصان ووجود االختبار جميع نماذجداد بزيادة سرعة جريان الهواء ولالمنتقلة تز ( زعنفة 67لة من نموذج اختبار )كمية الحرارة المنتقوان إن معامل انتقال الحرارة يزداد بشكل عام مع زيادة عدد رينولدز األفق. mailto:kut72@yahoo.com.au al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 استنباط عالقة تجريبية تربط كل من تم على الرغم من زيادة المساحة السطحية. المستطبل المقطعنموذج المن مثلثة المقطع اعلى ( ولنموذجي االختبار كما يلي:nu( وعدد نسلت )reعدد رينولدز)  ( زعنفة مثلثة المقطع : 67نموذج اختبار )  ( زعنفة مستطيلة المقطع67نموذج اختبار ) :  نموذج اختبار بدون زعانف nomenclature unit explanation symbol m 2 un finned area of the cylinder. acy m 2 total area of the fins. af m 2 side area of fin has different section. ascl m 2 inner surface area of cylinder. asi m 2 total area of cylinder. at kj/kg.k specific heat at constant pressure. cp m diameter of cylinder at the fin base. dp m inner diameter of cylinder. di m outer diameter of cylinder. doc _ grashof number. gr w/m 2 k convection heat transfer coefficient. h amp. electrical current. i w/m.k conduction heat transfer coefficient of air. k w/m.k conduction heat transfer coefficient of aluminum. kf m the length of fin. l m inclined length of the different cylinder. ls m height of fin. lf _ number of thermocouple position along the finned n _ number of fins. n _ nusselt number. nu _ prandtl number pr w/m 2 heat flux. q w heat transferred by forced convection. qconv. w generated heat by electrical current. qgen. w radiation heat transfer. qrad. _ rayleigh number. ra _ reynolds number. re _ the shape factor equal (1). ssur k ambient air temperature. tair k average film temperature. tf k average surface temperature of cylinder. tsav m fin thickness at the top. t1 m fin thickness at the base. t2 m/s maximum air velocity inside the duct. u volt voltage. v al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 greek symbols unit explanation symbol emissivity surface factor and equal (0.04). ε degres inclined angle of cylinder. θ kg/m.s dynamic viscosity . μ m 2 /s kinematic viscosity . ν _ the constant ratio and equal (3.14). π _ stefan boltzmann constant. σ 1introduction finned heat sinks are commonly used devices for enhancing heat transfer from central airconditioning devices. kenneths et al., 2001, air-cooled engines of motor cycles and automobiles , tubes of liquid-gas heat exchangers used in the refrigeration industry. ravi et al. 2008, solar collectors , nuclear reactor, cooling of electrical and electronic components and under ground electric transmission cables using pressurized gas and others, sakr et al., 2008. when the principles of heat transfer are used to used to design important engineering equipment such as heat exchanger. the designer work for important aim which is the developing the production to improve the economy and reducing the consumption of energy . for all that, economy with other technical specification play an important role in design and selecting the equipment of heat exchanger .the designer must take into account the weight and volume of heat exchangers which are specially used in aerospace and aeronautics and in this case will be a secondary factor. other factors such as efficiency and volume of heat exchanger are also considered important economic factors in these applications, fady r. s., 2009. there are many studies deal with the fluid flow and heat transfer in free and forced convection from plate surface and semi-cylindrical surface in (theoretical and experimental) methods .also there are many studies which deal with the heat transfer from the pulse and corrugated surface in the free and forced convection . in 1984, moon s., presented an experimental study [analysis of combined natural and forced convection around cylinders and spheres ] using cylindrical shapes and spherical shape. the equations for free and force convection ware: and accuracy about (93.5%) while the equation for forced convection was: for 70 < re < 3200 teertstra et al. 1999., performed an analytical modeling of forced convection in slotted plate fin heat sinks. an experimental measurements have been performed for a range of slot configurations, , 0.059≤ ≤0.44,for the range of reynolds number, 40≤ ≤180. an approximatate model is proposed that predicts the experimental results for the average heat transfer rate within a 12% rms difference . fady r.s., 2009., presented an experimental study of the effect of forced al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 convection heat transfer coefficient from circumferentially finned cylinder. the results of this study showed in the case of stationary cylinder for zero degree inclination and heat flux equal to (q=500w/ ),the formula was [ ]θ and for the same constants but for oscillating cylinder was: golnoosh m., 2012. investigated the steady-state external natural convection heat transfer from vertically-mounted rectangular interrupted finned heatsinks. a systematic numerical, experimental, and analytical study is conducted on the effect of the fin array and single wall interruption. fluent and comsol multiphysics software are used in order to develop a two-dimensional numerical model for investigation of fin interruption effects. results show that adding interruptions to vertical rectangular fins enhances the thermal performance of fins and reduces the weight of the fin arrays, which in turn, can lead to lower manufacturing costs. yoav peles et al., 2005. investigates heat transfer and pressure drop phenomena over a bank of micro pin fins. a simplified expression for the total thermal resistance has been derived, discussed and experimentally validated. geometrical and thermo-hydraulic parameters affecting the total thermal resistance have been discussed. it has been found that very low thermal resistances are achievable using a pin fin heat sink. in many cases, the increase in the flow temperature results in a convection thermal resistance, which is considerably smaller than the total thermal resistance. kavita h. dhanawade et al., 2014. using an experimental study to investigate the heat transfer enhancement over horizontal flat surface with rectangular fin arrays with lateral square and circular perforation by forced convection. the cross sectional area of the rectangular duct was 200 mm x 80 mm. the data used in performance analysis were obtained experimentally for fin arrays of material aluminum, by varying geometry and size of perforation as well as by varying reynolds number from 21* 10 4 to 8.7* 10 4 . it is observed that the reynolds number and size perforation have a larger impact on nusselt number for the both type of perforations. aiessa, et al, 2004,2008,2009,20012. studied the heat dissipation from a horizontal rectangular fin embedded with square perforation, rectangular perforations with aspect ratio of two, equilateral triangular perforations of bases parallel and towards its fin tip, by using finite element technique under natural convection. they compared the results of the perforated fin with its external dimensionally equivalent solid fins. they showed that perforation in the fins enhances heat dissipation rates. also, the heat transfer of perforated fin enhances with increase in the fin thickness data reduction -2 the convective heat transfer rate from electrically heated test surface is calculated by using a relation. the length of finned region which is subjected to constant and steady heat flux is (300mm) and the total quantity of heat generated in the electrical heater ( )is converted to heat. this heat transferred across the fin by conduction and from the cylinder to the ambient by forced convection ( )in addition to the heat loss by the radiation ( ). al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 the total quantity of generated heat is calculated as follow: the heat transferred by radiation is calculated as follows: yunus a., 1998. σ ε ( ) and, the heat transferred is calculated by convection as follows: therefore, the heat transfer coefficient in forced convection was calculated from the equation which is known as newton cooling law as follows: where : represents the surface area which is subjected to convection and equal to the finned area in addition to the un finned area which are taken into consideration. π π (11) the surface area was calculate for the test sample as follow: π √ ( ) where: al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 is corrected fin height. ( t) in equation (9) represents the difference between the average temperature for the cylinder and the supplied air temperature and then the average temperature for the cylinder is calculated as follows: while the average film temperature ( ) is calculated as follows: this temperature is taken to calculate the physical properties for the working fluid (air).according to the values of temperature and physical properties taken from the tables in j. p. holman, 2008. in order to calculate the heat flux exerted on the finned cylinder this requires calculation of the generated power due to passing the electrical current in a heating resistance by applying the equation (6).where the surface area which is subjected for this power is the internal area for the finned cylinder and is calculated as follows: π 3experimental setup details the aim of this study is to know the thermal behavior for a longitudinal finned cylinder with triangular ,rectangular section and cylinder without finns inside air (for in compression fluid) for a velocity range between (0.5 – 4 m/s) ,and the inclined angle was (0° and 45°), also the steady is at constant heat flux between (13 – 247w/ which can be obtained from the device. in order to study the air velocity effect (u) and the inclined angle on the overall heat transfer coefficient and the dimensionless parameter value which represent reynolds number (re) and nusselt number (nu) , this section includes an explanation for the method of system design has been used to achieve this aim. a suitable area for heat exchanger surface for measuring the temperature along the surface to calculate the overall heat transfer coefficient and the dimensionless parameter. using a cylinder contains a longitudinal fins with triangular, rectangular section as shown in the fig.1. the heating was under constant heat flux condition with the possibility of heat flux change using variable transformer. the test device components include the air duct ,which has been manufactured from plywood material , has a square section (60cm 60cm) and length(2 m), the duct entrance is manufactured in quadrilateral pyramid shape. pyramid crown contains a circular opening in order to fix the air blower. in way to prevent the existence of any obstruction inside the air duct to make the air flow easy and reduce effects of the obstruction . also in one of the air duct walls a glass gate is manufactured at distance (30cm) from the open end of the duct . its length (40cm) and it's high (56cm) in order to reach to the sample in case of fixing it or change the inclined angle. also the air duct is supported by angled iron support in order to fix the air duct as shown in the fig.2. air blower which used is operating according to centrifugal principle with power (350 w). it has an al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 22 opening to come at the air at circular shape with diameter (0.0635 m). also this blower contains a gate in order to select the air quantity at the entrance point and from it we can select the velocity inside the air duct .three positions are selected to open this gate in order to give three values of different velocities between (0.5 4m/s) inside the air duct. three test samples, made from aluminum with cylindrical shapes, longitudinal finned (12) fins and triangular, rectangular section and without finns have been used . these samples are manufactured by milling machine from one piece, with the total length about (320 mm) and the finned length about (300mm), the external diameter about (48 mm) and the fin height (13 mm). the internal diameter of the cylinder (16 mm) which is used for containing the heating mechanism under constant heat flux condition as shown in fig.1.the support was manufactured from cast iron material with angle may be changed to different position (0° and 45°) as shown in fig.3. the electrical circuit consists of heating coil power is (1000 w). the heating coil was put inside a glass tube from the pyrex and insulated by ceramics insulation at the ends. regavolt transformer was used of type (bristol conn 15 amp.). from it the electrical power supplied to the electrical coil can be controlled through changing the voltage with a range (20 100 v).because of the changing which happens in the electrical energy from the main source , voltage stabilizer was used of type (gold source svc 1500watt) to maintain the stability of supplied energy for the test device and the measurement devices . the device was of type (heme analyst 2050) . the supplied electrical power on the heating coil can be measured directly . using this device contains the voltage and current measurements can be obtained from this device and then multiplying these parameters to results in the supplied power at high accuracy . thermocouples were used of type k which were fixed on the longitudinal finned cylinder using the epoxy material which has heat resistance and high conductivity , six thermocouples were used distributed at equal distances along the cylinder .these thermocouples were connected to the selector switch (15 switches) and then connected to the digital thermometer. the selector switch was manufactured using plastic box .micro switch was fixed on it's face, and then the outlet points were connected to all switches with each other by thermocouple wires of type k and it were collected in one point . this point was connected to the temperature measurement device and when one switch is operated we can read the temperature at the selected point. digital thermometer used in this work is of type [tm-6862 ] and has ability to measure the temperature for a range [40 1200℃ ]. this device is fit with the thermocouple of type k only . it contains two inlets for thermocouples ( and ) and the selector switch can be changed from to as shown in. this device was used to measure the temperature from the finned cylinder surface by the thermocouples which are fixed on the finned cylinder surface ,at the fin base. digital anemometer used in this work is of type [e.schiltknechting .sia ch-8625 gossan zh,switzerland], shows the digital anemometer device which was used. basic processes are followed in the test experiments and the resulting are recorded in order to depend it on the analysis of effect of the inclined angle on the heat transfer coefficient in forced convection . the test sample and the support are fixed inside the air duct and then the test cylinder is heated according to the selecting heat flux, 13, 52, 109, 168 and 247 w/m 2 which is selected by the current and voltage and waiting for some time until reaching the steady state temperature case which take (3-4 hr) and recording the six thermocouples reading and calculating the average of it. operating the air blower system according to the selecting velocities in this and recording the temperatures. choosing another heat flux by changing of the input power. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 28 4result lab experiments have been performed using reynolds number ( ), heat flux ( ) w and inclined angle ( ) for the three samples in addition to inclined angle ( ) for test sample (12) rectangular fins to study the effect of inclined angle on heat transfer . nusselt number (nu) and reynolds number (re) have been calculated for all cases and the graphs has been drawn for each test sample as shown later where the results has showed the following. the relation between nusselt number (nu) and reynolds number (re) can not be represented by a straight line and as a result logarithmic equations have been used and acceptable results have been obtained. test sample (12) fins rectangular and for inclined angle (𝜃 ) with different ranges of velocity: test sample (12) fins triangular and for inclined angle (θ ) with different ranges of velocity : test sample without fins rectangular and for inclined angle (θ ) with different ranges of velocity: al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 89 test sample without fins and for inclined angle (θ ) with different ranges of velocity: where : from the general equation of heat transfer by external forced convection: the constants are obtained and the equations will be as follows: the test sample (12) fins with rectangular, tringular section and test sample without fins was: 5discussion the relation between nusselt number (nu) and reynolds number (re) for different geometry (triangular, rectangular and without fins) with inclined angle ( ) was shown in figure (4 to 6). it is shown that heat transfer by forced convection increases as reynolds number increases for the three samples . heat transfer from test sample with 12 fins (rectangular ,triangular) is higher than sample without fins due to increasing surface area and better heat transfer mixing due to the exisisting fins. also the heat transferred from test sample 12 fins triangular shape is greater than rectangular shape because the most fins is constant thickness encountered in practice, the fin thickness t is too small relative to the fin length l, and thus the fin tip area is negligible. the fins with triangular profiles contain less material and are more efficient than the ones with rectangular profile, and thus are more suitable for application requiring minimum weight such as space application. the effect of the different air velocity on the rate of heat transfer with inclined angle ( ) for different geometry are show in figures (7 to 9). its show that the heat transfer increases with increasing the velocity of air flow because of increasing in heat transfer coefficient by forced al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 89 convection as a result heat transferred increases from fin where as air velocity is maximum , the cooling rate for fin increases. figures (10 to 12) show the relations between reynolds number and nusselt number for rectangular shape at different velocities and for inclined angles (0º and 45º). it is shown that heat transfer at inclined angle ( ) is greater than at ( ) because when the longitudinal grooves for test sample is in horizontal plane , it make the heating air to flow in uniform shape and as a result the rate of heat transfer increases . in the case of placing the sample at inclined angle ( ), the fins work as an obstacles to air flow and hence the flow will be turbulated and a thermal resistance will be added and due to all that the rate of heat losses from tube decreases. figure (13) shows the effect of the velocity of air flow on the rate of heat transfer for different velocities and inclined angle ( ) for rectangular test sample (12) fins .the figure shows that the heat transfer increases with increasing the velocity of air flow because of more heat is removed by forced convection. 6conclusions based on the analysis of the practical results obtained from the lab experiments and according to the graphs related to the effects of inclined angle , heat flux and reynolds number (re) on heat transfer , the following can be concluded: 1heat transfer decreases with increasing the inclined angle. 2heat transfer increases with increasing reynolds number (re). 3heat transferred from triangular test sample 12 fins is greater than that from rectangular test sample and that without fin types. 7reference [1] aiessa a. h. and fayez, “the effect of orientation of square perforations on the heat transfer enhancement from a fin subjected to natural convection”, heat and mass transfer, vol.40, pp. 509-515 , 2004. [2] aiessa a. h. and mohmmed i. al-widyan, “enhancement of natural convection heat transfer from a fin by ttriangular perforations of bases parallel and toward its tip”,applied mathematics and mechanics, vol. 29, pp .1033-1044, 2008. [3] aiessa a. h. and mohammed q. al-odat, “enhancement of natural convection heat transfer from a fin by triangular perforations of bases parallel and toward its base”, the arbian journal for science and engineering, 34 2b, pp. 531-544, 2009. [4] aiessa a. h., ayman m.maqableh and shatha ammourah, “enhancement of natural convection heat transfer from a fin by rectangular perforations with aspect ratio of two”, international journal of physical sciences, vol. 4 , pp. 540-547, 2009. [5] fady r.s. jazrawy , “experimental study of the effect of vertical vibrations on forced convection heat transfer coefficient from circumferentially finned cylinder ” , mechanical engineering department , university of technology , 2009. [6] golnoosh m., “natural convective heat transfer from interrupted rectangular fins”, m.sc. thesis, school of engineering science faculty of applied sciences, university of tehran, 2012. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 88 holman j.p. “heat transfer ” , 8 th edition (1999). [7] [8] holman j.p. , “heat transfer ” , 9 th edition (2008). [9] kenneth s . hildebrand , jr.seafood processing specialist, “fish smoking procedures for forced convection smokehouses ” , oregon state university extension serice sea grant oresu i – 01 – 001 ,(2001). [1] kavita h. dhanawade et al., “thermal analysis of square and circular perforated fin arrays by forced convection”, international journal current engineering and technology, e-issn 22774106, p-issn 2347-5161, 2014. [10] m aiessa a. h., “augmentation of fin natural convection heat dissipation by square perforations”, journal of mechanical engineering and automation, vol. 2, pp. 1-5, 2012. [11] moon, s., “analysis of combined natural and forced convection around cylinder and spheres”, ph.d. dissertation, agricultural engineering department, university of maryland, college park, md 20742,1984. [12] s. ravi kumar , g. ramamurthy and k . v. sharma , “numerical analysis for optimal dimensions of a circular fins with hyperbolic profile”, department of mechanical engineering vasavi college of engineering ibrahimbag, hyderabad -500031. andhra pradesh ,india,2008. [13] sakr et. al ,“natural convection heat transfer” , berkeley electronic press , 2008. [14] teertstra , culham and yovanoich , “analytical modeling of forced convection in slotted plate fin heat sinks .” , microelectronics heat transfer laboratory department of mechanical engineering , university of water 100, ontario, canada. [15] yoav peles et al., “forced convective heat t ransfer across a pin fin micro heat sink”, international journal of heat and mass transfer, vol.48, pp. 3615-3627, 2005. al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 88 figure (1) the two finned cylinder figure (2) the air duct. . figure (3) the support of fins air blower air duct test sample supports al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 88 figure (4) the effect of different geometry of fins on heat transfer rate s figure (5) the effect of different geometry of fins on heat transfer rate 3.60 3.70 3.80 3.90 4.00 log (re) 1.60 1.70 1.80 1.90 2.00 2.10 2.20 l o g ( n u ) theta = 0º , velocity = 0.5 m/s cylinder without fins cylinder with rectangle fins cylinder with triangle fins 4.30 4.40 4.50 4.60 4.70 log(re) 1.80 2.00 2.20 2.40 2.60 2.80 l o g (n u ) theta=0°, velocity=2.5m/s cylinder with out fins cylinder with rectangle fins cylinder with triangle fins al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 88 figure (6) the effect of different geometry of fins on heat transfer rate figure (7) the effect of air flow velocity on heat transfer rate without fin test sample 4.50 4.60 4.70 4.80 4.90 log(re) 1.60 2.00 2.40 2.80 3.20 l o g (n u ) theta=0°, velocity=4 m/s cylinder with out fins cylinder with rectangle fins cylinder with triangle fins 3.60 4.00 4.40 4.80 5.20 log(re) 1.70 1.80 1.90 2.00 2.10 2.20 l o g (n u ) cylinder with out fins velocity = 0.5 m/s velocity = 2.5 m/s velocity = 4 m/s al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 88 figure (8) the effect of air flow velocity on heat transfer rate triangular test sample figure (9) the effect of air flow velocity on heat transfer rate rectangular test sample 3.60 4.00 4.40 4.80 5.20 log(re) 2.00 2.20 2.40 2.60 2.80 3.00 l o g (n u ) velocity =0.5 m/s velocity = 2.5 m/s velocity = 4 m/s cylinder with tringle fins 3.60 4.00 4.40 4.80 5.20 log(re) 1.80 2.00 2.20 2.40 2.60 2.80 l o g (n u ) velocity = 0.5 m/s velocity = 2.5 m/s velocity = 4 m/s cylinder with rectanglar fins al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 88 figure (10) the effect of inclined angle on heat transfer rate figure (11) the effect of inclined angle on heat transfer rate 3.60 3.70 3.80 3.90 4.00 log(re) 1.60 1.70 1.80 1.90 2.00 l o g (n u ) cylinder with rectangle fins, velocity= 0.5 m/s theta = 0° theta = 45° 4.52 4.56 4.60 4.64 4.68 4.72 log(re) 1.80 2.00 2.20 2.40 2.60 l o g (n u ) cylinder with rectangle fins, velocity =2.5 m/s theta = 0° theta = 45° al-qadisiya journal for engineering sciences, vol. 8……no. 1 ….2015 82 figure (12) the effect of inclined angle on heat transfer rate figure(13) the effect of air flow velocity on heat transfer rate at inclined angle 45° 4.60 4.70 4.80 4.90 log(nu) 2.00 2.20 2.40 2.60 2.80 3.00 l o g (r e ) cylinder with rectangle fins, velocity=4 m/s theta = 0° theta = 45° 3.60 4.00 4.40 4.80 5.20 log(re) 1.60 1.80 2.00 2.20 2.40 2.60 l o g (n u ) cylinder with rectagle fins, theta = 45° velocity = 0.5 m/s velocity = 2.5 m/s velocity = 4 m/s al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 386 assessment of embedding phase change materials in heavyweight buildings in iraq using esp-r alaa liaq hashem phd, department of mechanical engineering, college of engineering, al-qadisyah university, aldiwanyah, iraq. email address: alaaliag@yahoo.com received 16 june 2015 accepted 21 july 2015 abstract the traditional approaches employ massive components to moderate temperature fluctuations. the thermo-physical properties of the construction materials will have a strong influence on a building’s energy consumption. within a passive solar design, the heat capacity of the inner wall layer is dominated. this approach is applicable in locations that have effective daily temperature variations, else that, heavy weight constructions can give rise to problems of excessive thermal mass and cost. the nature of the climate of iraq can be represented in a two typical seasons; short and cold winter and long, hot and dry summer with short periods of the moderate months. the daily temperature variation is very limited and causes to accumulated heat in the buildings of heavy mass. the use of cooling system, in hot climate, is increased especially with heavy mass constructions. in iraq, more than 6 million new building unit should be added until 2020, the rapid growth in building sectors become the largest consumer of electric power produced, where the building sector consumes more than 38% from the total energy produced. in this investigation, the phase change materials behaviour was embedded within traditional heavyweight building internal surfaces. the two identical simple single zones modelled and simulated in a professional energy systems program called esp-r. global meteorological database software called meteonorm7 has been used to generate a climate file for baghdad city (33.3 o n and 44.4 o e) into esp-r program. the results represent a preliminary investigation into the effect of pcm modelling with heavy structured construction under hot climate. in addition, a comparison of an internal surface with different phase change temperature ranges. it is found that the presence of pcm could have a significant effect on the internal surfaces and thus the zone temperatures. the results encourage a full yearly investigation for the tested model, the simulation under realistic operational loads and with fixed internal boundary conditions underneath control loops using appropriate heating, cooling and ventilation strategies. keywords: phase change materials, pcm, building energy simulation, latent heat storage, thermal energy storage. thermal mass. esp-r. الخالصة وتوفيرفي درجات الحرارة الخارجية لتقلباتلمعادلة ا وكتل كبيرةبأبعاد توظف مكوناتالمستخدمة في البناء النهج التقليدية .يائية لمواد البناء يكون لها تأثير قوي على استهالك الطاقة في المبانيالفيز-الخصائص الحرارية .معتدلةداخلية درجات الحرارة النوع من هذا على الخصائص االخرى. السعة الحرارية لطبقة الجدار الداخلية خاصيةهيمن ت ضمن التصميم الشمسي السلبي، يمكن أن كتلةأن اإلنشاءات الثقيلة الفإال وليومية، قابلة للتطبيق في المواقع التي لديها اختالفات فعالة درجة الحرارة االتصميم يكون أن طبيعة المناخ في العراق يمكنان .العالية التكلفةوأيضا الكتلة الحرارية الزائدة ارتفاع درجات الحرارة بسبب تؤدي إلى مشاكل اف مع فترات قصيرة من جالالطويل، حار و وفصل الصيففصل الشتاء القصير والبارد ،ينتكون ممثلة في موسمين نموذجي mailto:alaaliag@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 387 كتلة الفي المباني من المخزنة خصوصاالحرارة تراكم للغاية ويسبب الحرارة محدود درجات ل اليومي تباينان .المعتدلةاألشهر عفي العراق، م .كتلة ثقيلةذات خصوصا مع المنشآت بشكل فعال ، ويزداد هو الشائع في المناخ الحار استخدام نظام التبريد ان.ثقيلة قطاع أصبح السكنية قطاعاتالالنمو السريع في بناء بسبب ، و0202ماليين وحدة بناء جديدة في عام 6أكثر من الحاجة الى تم دراسة البحث،في هذا .٪ من إجمالي الطاقة المنتجة83من يستهلك أكثرمستهلك للطاقة الكهربائية المنتجة، حيث أكبراالسكان المقارنة تمت مع حيز اخر مطابق ال يحتوي في ة. الثقيل الكتلة ذو الداخلية للمباني لمبنىداخل األسطح متغيرة الطورسلوك المواد وقد استخدم .esp-r تسمى محاكاةجدرانه الداخلية على هذه المادة وضمن نفس الشروط التشغيلية عن طريق استخدام برنامج تم حيث 44.4eو n 88.8المناخ لمدينة بغداد بياناتلتوليد meteonorm7الجوية برنامج قواعد البيانات العالمية لألرصاد جيد البناء الثقيلة منظم مواد مع المدمجة pcm النتائج تمثل تحقيقا أوليا في تأثيروكانت .esp-r إدخال البيانات في برنامج متغيرة الطور ذات وادمبين سطح داخلي مع وباإلضافة إلى ذلك، يتم إجراء مقارنة .تحت المناخ الحارلدرجات الحرارة للحيز النتائج حيز. انخلية وبالتالي درجة حرارة اليمكن أن يكون له تأثير كبير على األسطح الدا pcm أن وجوددرجات طور مختلفة. ط الداخلية ثابتة شروتثبيت واقعية ومع المحاكاة تحت األحمال التشغيلية اجراء الو لنموذجلتحقيق سنوي الكامل اجراء تشجع على .تدفئة والتبريد والتهويةال السيطرة على استخدام استراتيجياتب 1. introduction the distribution of thermal mass within a building is the result of structural and architectural decisions and can greatly influence how the building reacts to internal heat gains, solar radiation entering the building or changes in outside conditions. lightweight components react quickly to changes in internal gains and radiation. the traditional approaches employ massive components to moderate temperature fluctuations. the thermo-physical properties of the construction materials will have a strong influence on a building’s energy consumption. within a passive solar design, the heat capacity of the inner wall layer is dominated. in this approach is applicable in locations that have effective daily temperature variations, else that, heavy weight constructions can give rise to problems of excessive thermal mass and cost, (sara and mina, 2012). the nature of the climate of iraq can be represented in a two typical seasons, short and cold winter and long, hot and dry summer with short periods of the moderate months. the daily temperature variation is very limited and causes to accumulated heat in the buildings of heavy mass, (kazem et al, 2012). the use of cooling system, in hot climate, is increased especially with heavy mass constructions. in iraq, with more than 6 million new building unit in 2020 , the rapid growth in building sectors become the largest consumer of electric power produced, where the building sector consumes more than 38% from the total energy produced, (moelc). through the integrated of a phase change materials (pcm) to traditional building materials will improve the thermal properties of these materials, especially thermal capacity. the increasing in thermal capacity could shift most of the load coming from residential air conditioners from peak to off peak time periods (khudhair and farid, 2004). integrating phase change materials within light construction showed efficient reduction in cooling and heating load especially in cold and moderate climate regions, (neeper, 2000). the present work will assess a building model with heavy structures integrated phase change materials (pcm) within the internal material layers. the model simulated and tested in baghdad climate conditions using esp-r (energy simulation program for research) program, (esp-r). 2. pcm and field of applications the fields of pcm’s applications can be divided into high storage density for storage heat or cold, temperature control and thermal resistance contact enhancements. pcm’s can be integrated in both building materials and buildings components; implemented in gypsum board, plaster board, mixing with concrete or other wall finishing materials. thermal storage can be part of the building structure even for lightweight buildings; also can be part in heating ventilation and air conditioning (hvac) systems, (zalba, 2003). there are several types of organic and inorganic chemical materials that al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 388 can classified as pcm’s according to melting temperature and latent heat of fusion. in general, inorganic materials have almost double volumetric latent heat storage capacity (250–400kj/m 3 ) than that of the organic materials (128–200 kj/m 3 ), (sharma et al., 2009). the pcm must encapsulated so that it does not affect or change the function of the building construction material. three ways are used as means of pcm integration with an any component; direct incorporation, immersion and encapsulation. the first and second types affect the function of the construction material due to the direct contact with construction materials. for examples, concrete blocks impregnated with pcm’s and pcm’s mixed with heating/cooling system working fluid. the third one can be defined as the containment of pcm within a capsule of various materials forms and sizes prior to incorporation so that it may be introduced to the mix in a convenient manner. in macro-encapsulation, the inclusion of pcm in some form of containers such as tubes, pouches and spheres in boards, (pasupathy et al., 2008). microencapsulated of paraffin wax, which work as phase change material covered by polymer was prepared locally in iraq. the diameter of the prepared capsules was about (170-220) micron, the thermal analysis appears as a best value of enthalpy which was (12 j/gm) when the temperature was (60˚c), (mohammed et al., 2012). 3. building model and background information 3.1 esp-r program esp-r is a modelling tool for building performance simulation. in undertaking its assessments, the system is equipped to model heat, air, moisture light and electrical power flows at user specified spatial and temporal resolution. (esp-r). the esp-r allow to modelling and simulation pcm effect within buildings context using special materials components facilities. in esp-r, phase change occurred between melting phase (pcm becomes melts) and solidification phase (pcm becomes solidified) temperatures. below melting temperature, pcm is considered as a solid and the conductivity of the layer is equal to conductivity in solid phase. over melting temperature, pcm is considered as a liquid and conductivity of the layer is equal to conductivity in liquid phase. beyond phase change temperature range, latent heat of material is equal to zero, (heim and clarke, 2004). 3.2 weather information a global meteorological database software called meteonorm7 used to generate a climate file for baghdad city (33.3 o n and 44.4 o e) as input data for esp-r program, (meteonorm). meteonorm 7 generate a climate database for long period 19912010. the climate data sets interpolated from the satellite data for nearest climate stations from baghdad city location. the weather file exported from epw format (energy plus weather) to binary format (esp-r climate file format) using meteonorm converter tools facilities (esp-r). the climate data sets interpolated from the satellite data for the nearest climate stations from baghdad city location. fig. 1 and fig. 2 shows the dry air temperature in degree-centigrade and the direct radiation in w/m 2 . weather data for baghdad city define the boundary condition for the simulations. corresponds to the hottest summer between 1991 and 2010. the average ambient air temperature from june to august is 32.49 o c and the maximum direct normal solar radiation is 812.8 watt/m 2 . the period from the beginning of june to the end of august was selected for the analysis. 3.3 building model to investigate the effect of pcms effect, a two identical simple single rooms introduced in esp-r, as shown in fig 3. the model has dimensions of (5 m * 4 m) and a height of 3m. there is a single al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 389 window with double glass south facing with 15% the south wall. esp-r has an adopted database of materials and construction layers that can used directly or modified. in this model a new structure databases created to representing heavy weight structure used in traditional iraqi’s buildings as shown in table 1. pcm layers placed inside the interior surface for three walls only (walls-2, 3 and 4) as shown in fig.3. a typical phase change material is of the liquid-solid type, where energy is stored as latent heat during the phase change of the material. the phase change temperature selected in range 2°c and the latent heat of fusion is 1000j/kg k. the physical properties summarized in table.2. no cooling system used to control the space temperature, only the solar load considerate in this investigation. 4. numerical setup and results analysis the interior layer made from 10 mm of pcm–gypsum composite layer, this applied to all surfaces except the floors, roof and wall-1in the room and test-room zones. based on the dry bulb ambient temperature and the room model resultant temperature profile obtained from the initial simulation (no pcm), the melting-solidification temperatures selected to be 24-26, 25-27, 26-28 and 28-30 o c respectively. the phase change temperature rang was assumed to be 2 o c in each case. in addition, each case has the same value of latent heat of fusion given by 24000 j/kg. the simulation period selected between june and august 2007 as shown in fig. 2. 4.1 walls temperatures the figure 4, 5 and 6 showing the internal surface temperature of the walls 2, 3 and 4 with pcm. the pcm has a significant effect on the internal surfaces temperature, especially for the days when the pcm temperature reach its phase change range. while, there is no difference for the days with the temperature outside the phase change temperature range (below/above). it is therefore behaving as a regular sensible material. thus, as long as the phase change materials in charging-discharging continuously, there will be a visible effect on room temperature. because the two models not supported with a cooling and air ventilation-infiltration systems, the rooms space temperature is allowed to increase, thus, the pcm reach the full charging state and the temperature of the internal surfaces of the test-room increased steadily. for comparison, all the figs. 4-7 taken at the same snapshot in time (june to august). the snapshots chosen to clarify the differences between walls with pcm (test-room model) and without pcm (room model). a pcm layer with phase change rang 24-26 o c shown in fig. 4, the temperature profiles for surfaces with pcm diverted from first days of simulation and the temperatures decrease below the surfaces without pcm. the same behaviour is founded in all other phase change ranges while the delay depends on the value of melting temperature. 4.2 room temperatuers the thermal response of the internal surfaces affects the internal zones temperature. figs. 8–11 show the temperature profiles snapshot for room and test-room model over a selected simulation periods. an analysis of these data does not show significant differences in the zone’s temperatures profile. the phase change material succeeded in avoid the rise of the internal surfaces temperature in test-room's walls, where the reduction achieved compared with the surfaces, which does not contain this materials. through the figures, it can be noted that the length of this effect depends on the melting temperature and the solidification temperature, because the absence of both cooling and ventilation systems the internal zones temperature continue rising. the other reasons, the floor, glazing, wall-3 and ceiling components receiving solar energy and causing warming the zone space. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 390 thus, the pcm temperature out of the phase change range. the other reasons, the floor, glazing, wall-3 and ceiling components receiving solar energy and causing warming the zone space. thus, the pcm temperature out of the phase change range and kept in continuous charging state. 5. conclusions and remarks different strategies can be used for integration pcm within walls, celling and ground components. the purpose depends on the pcm layer location within the construction, the pcm located an interior layer for controlling zone temperature with cooling or heating processes where the application should be with phase change range. if the pcm located in the external layer, the pcm phase change temperatures should responding with ambient temperature and react as insulation materials with high latent heat capacity. while, if the pcm located in internal layer, the phase change limit equal the comfort temperature range of the users. in this investigation, the effect of phase change material embedded within heavy structured buildings using building energy simulation software called esp-r. a comparison of an internal surface with different phase change temperature ranges is made. the results represent a preliminary investigation into the effect of pcm modelling with heavy structured construction under hot climate. it is found that the presence of pcm could have a significant effect on the internal surfaces and thus the zone temperatures. the results encourage a full yearly investigation for the tested model, the simulation under realistic operational loads and with fixed internal boundary conditions under control using appropriate heating, cooling and ventilation strategies. 6. references [1] a.m. khudhair, and m.m. farid, 2004, a review on energy conservation in building applications with thermal storage by latent heat using phase change materials, energy conversion and management, 45, 263–275. [2] a. sharma et al., 2009, review on thermal energy storage with phase change materials and applications, renewable and sustainable energy reviews, 13, pp 318–345. [3] b. zalba et al., 2003, review on thermal energy storage with phase change: materials, heat transfer analysis and applications, applied thermal engineering, 23, pp251–283. [4] d. heim and j.a. clarke, 2004, numerical modelling and thermal simulation of pcm– gypsum composites with esp-r, energy and buildings, 36, pp: 795–805. [5] esp-r, energy system program for research, http://www.esru.strath.ac.uk/programs/espr.htm. [6] h.a. kazem, m.t. chaichan, status and future prospects of renewable energy in iraq, renewable and sustainable energy reviews, no. 16, pp: 6007–6012. [7] h. s. mohammed et al., 2012, a new method for preparation of microencapsulated phase change materials (pcms) for low coast energy in cooling of building, ibn alhaitham journal for pure and applied science, vol. 25, no. 3. [8] moelc, ministry of electricity, http://www.moelc.gov.iq, statistical data. http://www.esru.strath.ac.uk/programs/esp-r.htm http://www.esru.strath.ac.uk/programs/esp-r.htm http://www.moelc.gov.iq/ al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 391 [9] meteonorm, www.meteonorm.com. [10] neeper, d. a., 2000, thermal dynamics of wallboard with latent heat storage, solar energy, 68, no. 5, pp393-403. [11] sara m. and mina a.,2012, energy analysis of using thermal mass in a hot humid climate, recent advances in energy, environment and economic development, isbn: 978-161804-139-5. [12] pasupathy, a. et al., 2008, phase change material-based building architecture for thermal management in residential and commercial establishments, renewable and sustainable energy reviews 12, no. 1, pp: 39-64. table.1: test roof and walls constructions. table.2: pcm specification. property value phase change temperature rang ( o c) 2 conductivity in solid phase j/kg 0.4 conductivity in liquid phase j/kg 0.8 specific heat (j/kg k) 1000 walls external/cement layer (mm) 25 brick layer (mm) 240 cement layer (mm) 20 internal/ gypsum layer (mm) 10 roof concrete tile layer(mm) 25 sand layer(mm) 100 corks layer(mm) 50 mastic layer(mm) 5 heavy mix concrete layer (mm) 150 cement layer (mm) 20 gypsum layer (mm) 10 http://www.meteonorm.com/ al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 392 figure (2): dry bulb air temperature boundary conditions. simulation period phase temperature rang figure (1): direct normal solar radiation boundary conditions. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 393 figure (3): building model (identical rooms with and without pcm). pcm-layer inside outsid e walls-2,3,4-room walls-2,3,4-test-room figure(4) : the internal surface temperature for walls 2, 3 and 4 without pcm and pcm (melting temp. = 24 o c and solidification temperature. =26 o c) simulation period june-august. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 394 figure (5): the internal surface temperature for walls 2, 3 and 4 without pcm and pcm (melting temp. = 25 o c and solidification temperature. =27 o c) for period june-august. walls-2,3,4-room walls-2,3,4-test-room figure (6): the internal surface temperature for walls 2, 3 and 4 without pcm and pcm (melting temp. = 26 o c and solidification temperature. =28 o c) for period june-august. walls-2,3,4-room walls-2,3,4-test-room al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 395 figure (7): the internal surface temperature for walls 2, 3 and 4 without pcm and pcm (melting temp. = 28 o c and solidification temp. =30 o c) for period june-august. walls-2,3,4-room walls-2,3,4-test-room figure (8): room temperature with and without pcm (melting temp. 24 o c and solidification temp. 26 o c). room test-room al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 396 figure (10): room temperature with and without pcm (melting temp. 26 o c and solidification temp. 28 o c). room test-room room test-room figure (9): room temperature with and without pcm (melting temp. 25 o c and solidification temp. 27 o c). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 397 figure (11): room temperature with and without pcm (melting temp. 28 o c and solidification temp. 30 o c). room test-room al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 045 desorption of lead, copper and zinc from iraqi silty contaminated soil received 1 jun 2015 accepted 21 october 2015 abstract this study presents an experimental investigations undertaken to evaluate the effect of two extractant solutions (edtana2 and/or citric acid) and different conditions (ph, extractant concentration, and contact time) on the removal efficiency. iraqi silty soil are studied, the soil was artificially contaminated with lead (pb), copper (cu) and zinc (zn) to achieve higher levels of contamination. a series of batch experiments were conducted to determine the removal efficiency of lead, copper, and zinc using edtana2 and/or citric acid. the influence of solution ph, extraction time, and extractant concentration were studied in order to evaluate the optimum condition for soil washing process. the feasibility of soil washing method for decontamination of soil was evaluated in laboratory scale batch experiments. soil samples containing 500 mg/kg of pb, cu, or zn were subjected to ethelenediaminetetraacitic acid disodium salt (edtana2) and/or citric acid (ca) treatment. soil washing experiments performed on 2.0 g portions of the spiked soil using (0.001, 0.005, 0.01, 0.05, and 0.1m) chelating agents at a solid:liquid ratio of 1:10 showed that extraction efficiency of edta-na2 was much higher than that of citric acid, and higher concentrations of complexing agent lead to better extraction. results show that edta-na2 was better in releasing soil-bound metals from the soil compared to citric acid where 67.13% of lead was extracted using 0.1m of edta-na2 while only 36.5% was extracted using the same concentration of ca. up to 51.48% of copper was extracted using edta-na2 while only 24.86% was extracted using ca. similar results appear for zinc, where 44.2% was extracted using edta-na2 and 16.73% was extracted using ca. the highest extraction values of lead can be observed at ph values from 4 to 5 , copper at ph= 8 and zinc at ph = 9. key words: contaminated soil, heavy metals, soil washing, extraction. انتزاع الرصاص والنحاس والزنك من تربة عراقية غرينية ملوثة dr. hatem asal gzar wasit university/college of engineering e-mail: hatem_g15@uowasit.edu.iq zahraa hassan mottar wasit university/ college of engineering ل كزارـحاتم عس د. جامعة واسط/ كلية الهندسة زهراء حسن مطر جامعة واسط/ كلية الهندسة al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 045 الخالصة امين ثالثي حامض الخليك تهدف الدراسة الى اجراء تحريات عملية لتقييم تأثير محلولين لالستخالص هما ملح صوديوم اثيلين داي (na2edta) حامض الستريك على كفاءة االزالة عند ظروف مختلفة للرقم الهيدروجيني وتركيز المستخلص وزمن التماس. و ان الدراسة تمت على تربة غرينية عراقية تم تلويثها بالرصاص والنحاس والزنك لغرض الحصول على مستوى عالي للتلوث في يتم تحضيرها. نماذج التربة التي و edtana2اجريت سلسلة من تجارب الدفعة على التربة الملوثة لتعيين كفاءة ازالة الرصاص والنحاس والزنك باستخدام تم دراسة تأثير الرقم الهيدروجيني للمحلول وزمن التماس وتركيز المستخلص لغرض تحديد الظروف المثلى .حامض الستريك لعملية غسل التربة. راسة جدوى طريقة غسل التربة الزالة الملوثات من التربة تمت من خالل تجارب الدفعة المختبرية. ان نماذج التربة الملوثة ان د .حامض الستريك و edtana2 ملغم/كغم رصاص او نحاس او زنك تم معالجتها باستخدام المستخلصين 500والتي تحتوي ، 0.005، 0.001غم من التربة الملوثة واستخدام المستخلصات بتراكيز 2 ان تجارب غسل التربة اجريت من خالل اخذ اعطى edtana2. اوضحت نتائج التجارب ان استخدام 10:1موالري و نسبة صلب: سائل تساوي 0.1, 0.05، 0.01 تقود الى اعلى كفاءة ازالة. ان اعلى كفاءة ازالة مقارنة مع حامض الستريك، كذلك ان استخدام تراكيز عالية من المستخلصات edtana2 67.13كان االفضل في انتزاع المعادن الثقيلة )الرصاص والنحاس والزنك( من اواصر التربة ، حيث تم ازالة% من الرصاص باستخدام نفس التركيز من حامض الستريك. اما %36.5بينما تم ازالة edtana2 من الرصاص باستخدام من الزنك %44.2% باستخدام حامض الستريك. كذلك تم ازالة 24.86و edtana2باستخدام 51.48%زالة النحاس فتم ا باستخدام حامض الستريك. ان اعلى كفاءة ازالة للرصاص كانت عند رقم هيدروجيني 16.73%و edtana2باستخدام .9روجيني والزنك عند رقم هيد 8والنحاس عند رقم هيدروجيني (5-4)يتراوح بين 1. introduction heavy metal contamination of soil is one of the most important environmental problems throughout the world (doumett et al., 2008; nouri et al., 2006; wuana et al., 2010). the ability of heavy metals to accumulate and cause toxicity in biological systems humans, animals, microorganisms and plants has been reported ( nouri,1980; d’amore et al., 2005; wuana et al., 2010). as chemical hazards, heavy metals are non-biodegradable and can remain almost indefinitely in the soil environment. however, their availability to biota can change considerably depending on their chemical speciation in the soil. the adequate protection and restoration of the soil ecosystems, therefore, require the characterization and remediation of soils that are contaminated with heavy metals (nouri et al., 2008; nwachukwu et al., 2010; wuana et al., 2010). the most common heavy metals found in the contaminated sites are cadmium, chromium, copper, lead, mercury, nickel and zinc. these heavy metals are one of the main sources of environmental pollution and affect the human health, life of animals. the main sources of heavy metals are industrial discharge, energy production, chemicals used in agricultural production, construction, vehicular exhaust and particulate emission, coal and fossil fuel combustion. metals are relatively immobile in subsurface systems due to precipitation or adsorption reactions. for this reason, remediation activities at metals-contaminated sites mainly focused on the solid-phase sources of metals, i.e., contaminated soils, sludges, wastes, or debris (evanko, and dzombak, 1997). heavy metals cannot be destroyed by biogeochemical processes and site restoration relies on their removal (kirpichtchikova et al., 2006; uwumarongie and okieimen, 2010). numerous in-situ and ex-situ soil remediation technologies such as incineration, disposal in landfill, flotation, electroremediation, bioleaching, phytoremediation and chemical soil washing. developed for the treatment of heavy metal contaminated soils are based on two principles: immobilization, by increasing the retention of metal on soil or decreasing the mass transfer rate of metal; and mobilization, by the removal of metal from the soil matrix (kirpichtchikova et al., 2006; mulligan et al., 2001;benschoten et al., 1997; peters, 1999; irene and yang, 1999; khodados et al., 2005 ; uwumarongie and okieimen, 2010). al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 045 soil washing is represented one of the most suitable in-situ (on-site)/ ex-situ physical /chemical treatment technologies. soil washing method has been successfully used for the treatment of soils contaminated with heavy metals, hydrocarbons and semi-volatile organic compounds (svocs) (peters, 1999). soil washing usually employs different extractants such as acids, bases, chelating agents, electrolytes, oxidizing agents and surfactants (hong et al., 1995; schramel et al., 2000; reddy and chinthamreddy, 2000; sun et al., 2001). chelating agent has a high affinity for heavy metals, and may be used as remedial chemical treatment or in adjunct to another process. the efficiency of chelating agent in metal solubilization is high with less undesirable effects on the soil physicochemical properties. in addition, extraction agents are thought to enhance the bioavailability of metals in soil and thereby influence the iruptake by plants (kirpichtchikova et al., 2006; peters,1999). 2. materials 2.1 soils preparation and characterization in the experiments silty soil was used, the soil collected from a non-contaminated abandoned farmland located in aldujali in wasit governorate. after collecting soil from surface (0-20 cm), this was air dried at room temperature, sieved by using 2mm sieve to remove stones and large particles, and then thoroughly mixed with hand to ensure uniformity. the samples stored in a plastic bags at room temperature for further experiments. the physical and chemical characteristics of the soils are shown in table (1). the particle size distribution was performed by hydrometer method. soil water content was determined by direct method (soil moisture percent). soil ph and electrical conductivity were determined with help of hanna type ph meter after standardizing it with buffer solutions of ph 7.01 and 9.20. cation exchange capacity (cec) was determined following na2-acetate method. soil organic matter (om) was determined following walkley and black rapid titration method by oxidizing organic carbon in the soil with k2cr2o7 and back titrating the unutilized k2cr2o7 against feso4. background concentration of heavy metals was determined by acid digestion (hcl+hno3). all heavy metal analyses were performed by using atomic absorption spectrophotometer (aas) (novaa 300 (germany)). 2.2. contaminants since the concentration of heavy metals in soil samples is less than 100 mg kg -1 , the soil was spiked with pb, cu and zn to simulate a representative contamination. lead nitrate, copper nitrate, and zinc nitrate are used as sources of the pb, cu and zn respectively. a solutions of zn(no3)2.6h2o, pb(no3)2.6h2o and cu(no3)2.3h2o respectively (which are manufactured by scharlau company/spain) were prepared and added to the soil. the soil was spiked by adding these chemicals in distilled water to the air dried soil. the contaminated samples were equilibrated and dried by exposure at room temperature for at least two weeks and stored in plastic containers. the contaminant concentrations were measured according to acid digestion procedure followed by analysis with atomic absorption spectrophotometer (aas) (novaa 300(germany)). al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 045 2.3. extractants two chelating agents, ethelenediaminetetraacetic acid (edta) [ch2n(ch2cooh)ch2coona]2.2h2o with purity of 99.9% provided by panreac, (espana) and citric acid c6h8o7.h2o was obtained from panreac, (espana) with purity of 99.9%, were selected as chelating agents to examine the solubility of metals in complex forms. the efficiency of synthetic chelant (edta) was compared with a natural organic complexing chelant (citric acid). both edta and citric acid were used at concentrations of 0.001m, 0.005m, 0.01m, 0.05m, and 0.1m. 3. methods 3. 1 soil contamination procedure the required amount of the zn(no3)2.12h2o or pb(no3)2.6h2o or cu(no3)2.3h2o that would yield the desired concentration was weighed and then dissolved individually in distilled water. the contaminant solution was then added to the 1kg of the dry soil and mixed thoroughly with a stainless steel spatula in polyethylene container. 3.2. chemical analysis contaminant in different soil sections were extracted by performing acid digestion in accordance with the (haswell, 1991). total concentrations of lead, copper and zinc were determined using this extraction procedure. for this procedure, the soil samples were crushed and approximately of 1 g of a representative sample was weighed accurately in a beaker (capacity of 100 ml) and then mixed with 15 ml of concentrated hydrochloric acid (hcl) and 5 ml of concentrated nitric acid (hno3), the mixture was then heated in the heating sandy bath until the brown evaporation was disappeared and the sample arrived to dry state, this step takes about (45-60) minutes. then cooling the beaker to lab. temperature and then add 5 ml of concentrated hydrochloric acid (hcl) and then heated in the heating sandy bath, this step takes about (5-10) minutes. then cooling the beaker and add 5 ml of concentrated hydrochloric acid and 50 ml of heated distilled water to wash the sides of beaker from remains dissolved sample. after that heating the mixture to the boiling points to (2-3) minutes. then filtrate the sample with filtration paper no. 42, and then keep it in volumetric flask capacity of 100 ml., then, washing the precipitation with distilled water and addition of the previous washed water to filtration and complete the size to 100 ml. finally, the metal concentration was determined by atomic absorption spectrophotometer (aas). 3.3. soil washing procedure batch extractions of heavy metal contaminants using a various extractant concentrations and liquid/solid ratio of 10:1 were conducted in 250 ml conical flask. the flask contained 2 g of soil and 20 ml of edta or citric acid was agitated using an orbital shaker at a speed of 200 rpm at room temperature for 1 hr. the suspensions were centrifuged at 3000 rpm for 10 min and the supernatants were then filtered through 0.45µm whatman filter paper for heavy metal analysis. the concentrations of metals were measured by flame atomic absorption spectrometry (aas). in the experiment different operating variables for removal of heavy metals from soil using edta or citric acid, including the different extractant concentration, solution ph and operation time. in experiments, five different concentrations (0.001,0.005,0.01, 0.05, and 0.1) of na2edta or citric al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 044 acid were chosen. the ph from 4-9 was adjusted with diluted hno3 and naoh. the kinetic study was performed for 1, 2, 3, 4, 5 h. finally, the removal of each contaminant was calculated using the following equation (lim et al., 2005 ; reddy and chinthamreddy, 2000 ; gzar et al. , 2014): contaminant removal = where cl and cs are the concentration of heavy metals in supernatant (in mg/l) and soil (in mg/kg), respectively. vl is the volume of supernatant (in l), and ms is the dry mass of the soil (in kg). 4. results and discussion 4.1. extraction with edta 4.1.1. effect of ph solution ph is an important factor determining the efficiency of soil washing because it can influence the soil retention of metals by adsorption. experiments were performed in ph of 4, 5, 7, 8, and 9. nitric acid (hno3) and sodium hydroxide (naoh) were used for ph adjustment. as for most metals, the amount of extracted pb increase with lowering ph values as shown in figure (1). the highest extraction of lead can be observed at ph values from 4 to 5. at ph = 4, the removal efficiency of lead was 69.66%. for copper, at the lower ph values the removal efficiencies follow the predictable trend but unexpected increase occurs at ph 8 to 9. the maximum removal efficiencies for copper was 58.24% and this percentage achieved at ph = 8. at higher ph values a significant decrease occurs abruptly. the curves of the extraction of zinc as a function of ph are not smooth. additionally some results do not seem to be logical. the general trend is the decrease of extracted zinc at ph = 5 but increase after that with increasing ph value. for lower ph value the removal efficiency of zn was 46.6% while it reaches to 60.2 at ph = 9. the results in figure (1) is accepted with mohanty and mahindrakar (2011), which used edta to remove lead and cadmium from soil and the maximum removal of lead occurred at ph= 4. the results also accepted with mahvi et. al. (2005), which found that the recovery or desorption of lead from siltclayloam soil was generally greatest under acidic condition and decrease modestly as the ph become alkaline, accurately, they found that the remediation efficiency for lead in ph = 3 was approximately 10% more than in ph =9, but they observed a decrease of 4% in removal efficiency of zinc at ph =3 and that is may be due to distribution of metals in the different solid phase of the contaminated soil. niinae et. al. (2008) report that the removal of lead with edta is very high in the ph range from 4 to 10. however, it is considered that acid also contributes to the extraction of lead at ph= 4. 4.1.2. kinetics of extraction extraction time plays a very important role in soil washing. in order to comprehend the washing process and determined the optimum contact time for contaminants removal, a kinetic study was performed at different contact times (1, 2, 3, 4, and 5 hr) and different concentration of na2edta (0.001, 0.005, 0.01, 0.05, and 0.1m) and the result shown in figure (2). al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 040 the kinetic of lead extraction occurs within the first two hours then the curves stay nearly constant. at highest concentration, 63% of lead was extracted within the first two hours while increasing the reaction time for five hours will rise the removal efficiency of lead to 67.13% only. copper and zinc exhibit the same behavior observed for lead. the removal efficiencies of copper varied from 47.92% after 2 hours of extraction to 51.48% after 5 hours. the removal efficiencies of zinc varied from 58.01% after 2 hours of extraction to 60.2% after 5 hours at ph =9. the results of the present study indicated that a reaction time of 2 hr was considered suitable since the curves illustrate that no appreciable amount of metals was extracted beyond this time and this is agreed with mahvi et. al. (2005) which reported that the vacillation of remediation process results usually occurs in initial hours and then the efficiency will follow a constant rate, therefore the optimum time period which is used as a bench mark for comparison is 2 hr. bermond and ghestem (2001) reported a rapid initial release of lead and cadmium from contaminated soil into the edta extraction solution. khalkhaliani et al. (2006) also reported that 2 hr is the suitable for metal extraction from contaminated soil. 4.1.3. effect of extractant concentration chelating agents modify metal concentration in soil solution by forming various soluble complexes, thus enhance metal removal (reddy and chinthamreddy 2000). different concentrations (0.001, 0.005, 0.01, 0.05, 0.1m) of edta was used in the present study. the solidliquid ratio was 1:10 with shaking speed of 200 rpm and shaking time (1, 2, 3, 4, and 5 hr). no ph adjustment was made in these experiments. in figure (3), no appreciable extraction observed for lead at the lower concentrations of edta-na2. edta-na2 solution of 0.1m extract up to 67% of lead from the soil after 5 hr of extraction. for copper and zinc, no extraction occurs when low concentrations of edta-na2 (0.001 and 0.005) m were used. at concentrations of (0.01 and 0.05) m, no appreciable removal appear for these metals. for copper, the results show that at concentration of 0.1m 51.48% was extracted after 5 hr of extraction. 44.2% of zinc was extracted using 0.1m of extractant shaked for 5 hr. according to these results the maximum and minimum metal removal efficiencies achieved with 0.1m and 0.005m of edta-na2 and this is agreed with mahvi et. al (2005) and khalkhaliani et. al. (2006) reported that there was a cardinal effect of edta on lead removal; meanwhile the increase of the edta concentration in zinc has not a considerable effect on the remediation efficiency. 4.2 extraction with citric acid citric acid was selected as a natural organic complexing chelant to examine the solubility of metals in complex form. batch extraction experiments were conducted using citric acid solution at various concentrations (0.001, 0.005, 0.01, 0.05, and 0.1) m and contact times to determine appropriate range of concentration and dosage of the washing solution to achieve high heavy metals extraction efficiencies. 4.2.1. effect of ph to examine the effect of ph value on the efficiency of extraction, 0.1m of ca was added to the soil. experiments were performed in ph of 4, 5, 7, 8, and 9. nitric acid (hno3) and sodium hydroxide (naoh) were used for ph adjustment. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 045 copper and zinc follow the predictable trend (figure 4). the highest removals occur at the lower ph values. up to 38.5% of lead was extracted at ph = 4 after 5 hours of extraction. the amount of extracted pb decreases with increasing ph value steadily until reaches to 9.04% only at ph = 9. copper and zinc exhibit similar behavior. 26.6% of copper extracted at ph =4 while only 10.1% extracted at ph = 9. removal efficiencies of zinc varies from 20.9% at ph 4 to 8.33% at ph= 9. the drop in extraction for copper and zinc was about 30.5% and 31.2% respectively when ph value rises to 9. 4.2.2. kinetics of extraction figure (5) show that the significant extraction also occur within the first two hours and the increase in the removal efficiency after that time is not impressive. no removals occur for all metals at all times of extraction when 0.001m of ca was used (figure 5a). 33.15%, 24.1%, and 13.81%, of lead, copper, and zinc respectively were extracted when 0.1m of ca was used with contact time of 2 hours (figure 5 e), but after 5 hours of extraction only 36.5%, 24.86%, and 16.73% of lead, copper, and zinc respectively were extracted using the same concentration of ca. 4.2.3. effect of extractant concentration edta and citric acid (ca) are chelating agents modify metal concentration in soil solution by forming various soluble complexes. different concentrations (0.001, 0.005, 0.01, 0.05, 0.1m) of ca was used in this study with solidliquid ratio of 1:10 with shaking speed of 200 rpm for (1, 2, 3, 4, and 5 hr). no ph adjustment was made in these experiments. the results showed that the soil did not respond to the treatment with the lowest concentration of citric acid (0.001m) (figure 6). the maximum removal efficiencies achieved at the highest concentration (0.1m) at contact time 5 hours, where 36.5%, 24.86%, and 16.73% of lead, copper, and zinc respectively were extracted the soil (figure 6e). 4.3. comparison between edta and citric acid extraction edta could form strong complexes with heavy metals (manouchehri et al., 2006), however, citric acid is relatively a weaker complexant than edta. a comparison between edta and ca for removing of heavy metals, as a function of extractant concentration and contact time are shown in figures (7) and (8) respectively. results of the present study show that edta was better in releasing soil-bound metals from the soil compared to citric acid where 67.13% of lead was extracted using 0.1m of edta while only 36.5% was extracted using the same concentration of ca (figure 7a). up to 51.48% of copper was extracted using edta while only 24.86% was extracted using ca (figure 7b). similar results appear for zinc, where 44.2% was extracted using edta while 16.73% was extracted using ca (figure 7c). the ability of edta to enhance the release of metals from insoluble or sparingly soluble compounds compared to other chelating agents has been attributed to its higher binding capacity for metals as observed in other studies (blaylock et al., 1997; huang et al., 1997; wu et al., 1999). a study by nascimento et al. (2006) investigated the release of pb in soil solution after application of chelating agents viz. edta, dtpa, oxalic acid, citric acid, vanillic acid and gallic acid. authors concluded that edta was one of the most efficient chelating agents as it significantly increased the concentration of pb in soil solution after 24 h of application. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 045 5. conclusions 1. results of the present study show that edta was better in releasing soil-bound metals from the silty soil compared to citric acid where 67.13% of lead was extracted using 0.1m of edta while only 36.5% was extracted using the same concentration of ca. up to 51.48% of copper was extracted using edta while only 24.86% was extracted using ca. similar results appear for zinc, where 44.2% was extracted using edta while 16.73% was extracted using ca. 2. the highest extraction of lead can be observed at ph values from 4 to 5. 3. the maximum removal efficiency for copper was 58.24% and this percentage achieved at ph =8. 4. the maximum removal efficiency for zinc achieved at ph =9. 5. the results of the present study indicated that a reaction time of 2 hr was considered suitable since the curves illustrate that no appreciable amount of metals was extracted beyond this time. 6. the results showed that the silty soil did not respond to the treatment with the lowest concentration of citric acid (0.001m), while the maximum removal efficiencies achieved at the highest concentration (0.1m) at contact time 5 hours. 7. compared with citric acid, edta caused more extraction of metals at all the levels of application. overall the results from this study demonstrated that edta could potentially be used as an amendment to enhance metals mobility in soils and thus its availability to plants for removal from contaminated soils. references [1] benschoten j.e.v., matsumoto m.r., young w.h., (1997). evaluation and analysis of soil washing for seven lead-contaminated soils. j. environ. eng. asce, 123, 217-224. 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[32] wuana r.a., okieimen f.e., imborvungu j.a., (2010). removal of heavy metals from a contaminated soil using organic chelating acids. international journal of environmental science and technology.7 (3),485-496. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 005 table 1: composition and properties of the studied soil. property value particle size distribution sand (%) silt (%) clay (%) 7 85 8 cation exchange capacity (meq/100g) 28 initial ph 7.75 organic matter (om) 2.93 electrical conductivity ec (µs/cm) 5.4 moisture content % 4% porosity (n) 34.6% background concentration of heavy metals (mg/kg): pb cu zn 14 0 21 soil classification silty al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 005 (a) 1 hr (b) 2 hr (c) 3 hr (d) 4 hr (f) 5 hr figure (1): effect of ph on the removal efficiency of lead, copper, and zinc using 0.1m of edta at different contact times. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 005 (a) 0.001m (b) 0.005m (c) 0.01m (d) 0.05m (f) 0.1m figure (2): effect of contact time on the removal efficiency of lead, copper, and zinc using edta at different concentrations. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 005 (a) 1 hr (b) 2 hr (c) 3 hr (d) 4 hr (f) 5 hr figure (3): effect of concentration on the removal efficiency of lead, copper, and zinc using edta at different contact time. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 004 (a) 1 hr (b) 2 hr (c) 3 hr (d) 4 hr (e) 5 hr figure (4): effect of ph on the removal efficiency of lead, copper, and zinc using 0.1m of ca at different contact time. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 000 (a) 0.001 m (b) 0.005 m (c) 0.01 m (d) 0.05 m (e) 0.1 m figure (5): effect of contact time on the removal efficiency of lead, copper, and zinc using ca at different concentrations. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 005 (a) 1 hr (b) 2 hr (c) 3 hr (d) 4 hr (e) 5 hr figure (6): effect of concentration on the removal efficiency of lead, copper, and zinc using ca at different contact time. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 005 (b) copper (a) lead (c) zinc figure (7): comparison between edta and ca for removing of heavy metals as a function of extractant concentration. (b) copper (a) lead (c) zinc figure (8): comparison between edta and ca for removing of heavy metals as a function of contact time. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 225 thermal losses reduction for a trough collector: part 2 heat transfer dhafeer m. h. al-shamkhi wisam a. abd al-wahid foundation of technical education foundation of technical education technical engineering college/najaf technical engineering college/najaf alternative and renewable energy research unit automotive dept. received 31 august 2014 accepted 12 january 2015 abstract the heat losses by convection from the collector tube of a trough collector to the ambient are analyzed. the strategy to reduce such losses is by using a vacuum glass tube covering the collector tube. since the maintaining of this vacuum state is difficult, beside the high cost and easily broken off the glass tube, another strategy presented in this paper. the strategy based on reducing the overall convection heat transfer by the use of guides made of metal, which effect on the process of heat transfer. the guides put in front of the collector as a half circle with different dimensions, and each one analyzed numerically by using 4.4 comsol multiphysics program. the analysis include the streamlines behavior, temperature distribution, and average nusselt number. the minimum the nusselt number obtained the best arrangement to use. the data show a decrement in heat transfer process due to that modification with different percentages. keywordsthermal losses reduction; trough collector; combined free and forced convection; solar energy. انتقال الحرارةتقليل الخسائر الحرارية من مجمع شمسي: الجزء الثاني وسام احمد عبد الواحد ظافر مانع حاجم الشمخي هيئة التعليم التقني هيئة التعليم التقني الكلية التقنية الهندسية/ النجف الكلية التقنية الهندسية/ النجف قسم تقنيات هندسة السيارات وحدة بحوث الطاقة البديلة والمتجددة الخالصة: في هذا البحث, تم تحليل أنتقال الحرارة بالحمل من انبوب التجميع في المجمع الشمسي. وقد وجد بأن الستراتيجية المتبعة لتقليل انتقال الحرارة هي باستخدام انبوب مفرغ من الهواء يغطي انبوب التجميع . وبما ان تكلفة هكذا انبوب هي عالية ناهيك عن غ بسبب التسرب أو كسر االنبوب. لذا فقد قدم هذا البحث اسلوب جديد في تقليل الخسائر يقضي صعوبة المحافظة على التفري بوضع مصدات هوائية على شكل نصف دائري و بمختلف االقطار أمام انبوب التجميع وذلك للتاثير في عملية انتقال الحرارة. وقد ضم التحليل حساب خطوط الجريان وتوزيع السرع لغرض التحليل الرياضي المتبع. comsol4.1وقد تم استخدام برنامج ودرجات الحرارة. وقد تم حساب عدد نسلت والذي يعتبر مقياس تقليل الخسارة بالحصول على اقل عدد نسلت. وقد أوجدت الحسابات نقصاناً في الخسائر الحرارية من انبوب التجميع بسبب هذا التعديل وبنسب مختلفة. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 226 nomenclatures symbol description units thermal expansion coefficient j/kg.k d cylinder diameter m dhi hydraulic diameter at interring m dr diameter ratio f volume force n/m 3 k thermal conductivity w/m.k k turbulent kinetic energy m 2 /s 2 lt turbulence length scale m lt turbulence intensity m 2 /s 2 nu local nusselt number nua average nusselt number nufsp average nusselt number at front numax maximum average nusselt number numin minimum average nusselt number pressure n/m 2 pr prandtl number rei reynolds number at inlet temperature o k tamb inlet temperature o k trt receiver tube temperature o k ttw trough wall temperature o k u velocity field (u,v,w) m/s horizontal velocity m/s vertical velocity m/s w aperture of the parabolic collector m horizontal coordinate m y vertical coordinate m greek symbols symbol description units density of air kg/m 3 dynamic viscosity n.s/m 2 t turbulent dynamic viscosity n.s/m 2 ε rate of dissipation of kinetic energy m 2 /s 2 θ pitch angle degree 1. introduction solar energy is an essentially inexhaustible source of energy potentially capable of meeting a significant portion of all nation's future energy needs with a minimum of adverse environmental al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 227 consequences. the current industrial growth and environmental impacts show that solar energy for solar thermal power plants is the most promising of the unconventional energy sources. the future of the solar power plant development depends on a number of serious constraints, including scientific and technological problems are deals with the most common commercially available solar power plants use parabolic trough concentrators. parabolic trough collector (ptc) technology is one of a number of concentrated solar power (csp) conversion methods available today. ptc technology is becoming widely used for power generation and process heat applications. the reason for the success of ptc technology, that it is the most mature and one of the least expensive solar thermal energy technologies available in the market. where the thermal analysis in such solar collectors studied widely to find the optimum reduction of heat losses and collector efficiency with different flows, selective coating, and operating conditions (christ. 2012). in other hand, the whole model also studied thermally by using a finite volume method to analyze the heat transfer inside the collector, and using the monte carlo method to analyze the radiation heat transfer outside the collector (cheng. 2010). in addition for the previous works, the wind effect on the trough was taken in mind (kalogirou. 2012, hachicha . 2012, and cheng. 2012), where the measurements of wind load are tabulated (kalogirou. 2012). during this, the reduction of heat losses from the collectors took a great attention in order to reduce these losses (naeeni. 2007). these losses mainly shown as a convection heat transfer to the ambient (alansary. 2011), which is a function of pitch angle and trough orientation. the best strategy to reduce these losses is to use the vacuum glass tube in many arrangements (daniel. 2011), but the keeping of these tubes in vacuum situations is very difficult, which lead to another strategy of using insulations (padilla. 2011). in the present work, a detailed two dimensional heat transfer analysis of a ptc presented. three values of collector's orientations values taken as shown in figure 1 below. where this study focus on reducing the loss of heat from non-evacuated tube by convection to ambient for different wind speeds and by adding a half circular plate in front of the receiver as shown in figure 2. where the effect of this plate on the average nusselt number for the receiver tube studied for different wind speed, pitch angles, and different plate dimensions. 2. mathematical analysis the casual design of the parabolic trough collector is to put the receiver in the center of the trough. the receiver always covered with a glass tube with an intermediate space. this space is should be vacuum to ensure the reduction of the heat losses to the surrounding. the losses from the receiver to the glass cover is by radiation. then, the losses from the receiver to the ambient air is by convection. when the ambient air velocity is small, natural convection dominated. however, when the velocity of the air increased the forced convection effect increase until domination. since the purpose of the present work is to reduce the thermal losses from the collector by the trough shape changing, then the problem presented, at first, casually. consider a parabolic trough facing a wind stream as shown in figure 3. the trough fixed as shown with the ambient temperature, about 300 o k. the absorber tube fixed in the middle of the trough with a temperature of 350 o k, and a diameter of 11.5 cm. all the properties assumed to be constant, airflow is horizontally with a temperature of 300 o k, and the absorber surface temperature is uniform at the whole surface. since the aspect ratio between the troughs diameter to the receiver diameter is very big, then the problem assumed two-dimensional. regarding combined free and force convection when the ratio of gr/red 2 =1, momentum equation will be different and buoyancy should be included as described in (bejan. 2004). the governing equations for 2-d steady state incompressible fluid flow are time averaged navirstokes equations; rng-based k-ε turbulent scheme and energy equations as below: al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 228 ( ) (1) ( ) [ ( )( ( ) ) ( )( ) ] (2) ( ) [( ) ] (3) ( ) [( ) ] (4) [ ( ( ) ) ( ) ] (5) ( ) (6) (7) turbulence model parameters are: hydrodynamic boundary conditions for flow analysis are as follows:  inlet inlet velocity: (8) turbulent intensity: ( ) (9) turbulence length scale: (10) here: reynolds number at interring ( ) ( ) hydraulic diameter at interring al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 229  outlet outlet pressure: (11) [ ( )( ( ) ) ( )( ) ] (12) (13) (14) (15)  walls [( )( ( ) ) ( )( ) ] (16) ( ) (17) (18) (19) (20)  symmetry wall (21) [( )( ( ) ) ] (22) ( ) (23) (24) (25) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 230 thermal boundary conditions on the receiver tube and ambient for flow analysis are as follows:  inlet flow temperature: (26)  outlet flow : ( ) (27)  receiver tube temperature: (28)  trough wall temperature (29)  symmetry wall ( ) (28) 3. definition of the case and numerical model the geometry of a full-scale euro trough solar collector (l¨upfert. 2001) has been selected for this study. table 1 shows the specification of the euro trough solar collector. a typical hce (heat concentration element) with a stainless steel absorber inner/outer diameter of 6.6/7.0 cm and glass cover of 10.9/11.5 inner/outer diameter has been considered in the simulations. the computational domain is defined by (5w) in the upstream direction, (20w) in the downstream direction, (9 w) in the cross direction and (πw) in the span-wise direction, where w=5.8m is the aperture of the parabola (see the figure 4). the parabolic collector is usually large in length and the aspect ratio of the h ce is very large, thus the flow in span-wise direction can be assumed as spatially periodic. a uniform wind speed in the inlet velocity profile is considered. although, the ptcs are exposed to the atmospheric boundary layer, the uniform velocity assumption represents the worst-case scenario for structural loading and could be incorporated as a design safety factor (hachicha. 2012). slip conditions are fixed in the top and bottom boundaries, while at the outlet a pressure-based condition is used. at the mirror and hce surfaces, no-slip conditions are prescribed. as for the span-wise direction, periodic boundary conditions are imposed. the prandtl number is set to pr = ν/κ = 0.7 as for air. the temperatures of the glass cover and ambient air are fixed to trt = 350k and tamb = 300k, respectively. a neumann boundary condition (∂t/∂n = 0) is prescribed in the top, bottom and outlet boundaries for temperature. the mesh is refined around the collector surface; the hce near wake and then, stretched going away from the collector (see figures 5 &6). the mesh is suited for each case of pitch angle and with respect to the dimension of the problem. in order to capture the flow structures in the near wake of the ptc and around the hce, mesh requirements are higher in these zones. however, due to the large difference between the dimensions of the aperture of the parabola and the receiver tube, the construction of the mesh is quite dense and complicated near these elements. the minimum mesh quality is greater than 0.6 and average mesh quality about 0.97 for each pitch angle are presented.in table 2, the main characteristics of the meshes used for each pitch angle are given. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 231 the model treated as non-isothermal flow with turbulent k-ε model. the heat transfer done by forced convection for θ = 0 o , and 90 o , and by mixed free and forced convection for θ = 180 o . the reason behind these assumptions is the value of airflow velocities near the heat transfer region. the present problem solved by using a finite difference method by using comsol multiphysics v4.4 program solver. the iterative solution considered to have converged when the maximum of the residual across all nodes is less than 10 -6 for continuity, velocities, and temperature. the numerical results checked for grid independency. the procedure repeated when increasing the number of nodes until a stage reached where the results produce negligible changes with further refinement in grid size. as it seen in figures 5 &6, the meshing refined near the trough collector, and it extra refined near the receiver. the explanation of this meshing is the sever changes in velocities near the collector, and beside of the big change of temperature values near the receiver tube. 4. the validation of the present work the aim of the present work is to study the details of flow pattern around a receiver tube, and by combine solution of governing equations, determining thermal losses and convection heat transferring from the receiver tube. results presented by fluid flow pattern, thermal structure of air around the receiver tube and local nusselt number around it. based on the local variation of nu, average nu from the glass cover determined and comparison made with the proposed correlations for cross-flow conditions and pure free convection. validation of the present numerical scheme obtained by studying the fluid flow over cylinder in two-dimensional as described in (hachicha. 2012). the computational domain is extended to [−15d, 25d]; [−10d, 10d]; [0, πd] in the stream-, crossand span-wise directions respectively, and the cylinder with a diameter d is placed at (0, 0, 0). comparison also made to check the accuracy of thermal field by solving mass, momentum, and energy equation for the cross flow around a horizontal tube. the flow around the cylinder is symmetric and average convection heat transfer computed by the present simulation is the same as eq.(7.45) (incropera. 2011), as illustrated in figure 7. in table3, a validation done with the numerical data of hachicha.2012. the data checked with previous experimental work. table 3 shows the average nusselt number for the three orientations used in the present work of 0 o , 90 o , and 180 o . the third column shown in the table is the nusselt number at the front stagnation point. table 3 also shows the maximum and minimum nusselt number and the position of that number with degrees. table 3 shows a very good agreement with the literatures that proves the accuracy of the present's work procedure. 5. results after proving the accuracy of the present work, it is confidant now to find the effect of the suggested modification of the shape on the heat transfer process. figure 8 below shows the surface temperature distribution on the field for the values of three orientations. the figure shows how the receiver lost its energy to the air passing through it. the temperature of the air increased due to the direct contact with the tube surface. in the figure 8 (b) it is obvious that the temperature is slightly increased near the edge of the collector due to the increase of the velocity near that edge. this suggests the increase in the air energy. figure 8 (c) shows that the receiver high temperature's effect is only on the air near it. the effect dos not spread away due to the fact that the receiver is in the wake of the collector. therefore, the al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 232 air velocity near the receiver is very low, where the natural convection dominated and the effect of the buoyant effect appeared. in figure 9, the effect of the shape modification on the local nusselt number shown on the receiver with different diameter ratio of 1.3, 1.5, 1.7, and 2. the figures also show the ordinary case of no shape modification. the results show a decrease in the local nusselt number due to that modification. the astonishing result is the decrease of the overall values especially at the front stagnation point, where the maximum nusselt number occurs. the fact that the receiver is in the wake of the half-cylindrical disc added is the only explanation behind that decrement. the halfcylindrical addition cause a decrement of air velocities near the receiver. the values of the local nusselt number shown to increase to its maximum value at the area just at the end of the disc, where the nusselt number may increase again due to the facing of the rear part of the receiver to the wake of the flow. for these cases the addition of the half-cylindrical disc shown to cause a good reduction in the heat transfer losses. in figure 10, another values shown as in figure 9 above but for the case of 180 o . this case is where the mixed convection appeared. the data shows a slightly reduction in nusselt number values at the front stagnation point. the reduction increased with arc length of the receiver until reach its maximum value at the back of the receiver. figure 11, shows the average nusselt number with the addition of the half-cylindrical disc for different orientations, and different disc ratio. the figure started with ordinary case with no modification on the shape (the ordinary case). the values show that the maximum heat transfer occurred at 90 o orientation. the data also show how the shape modification causes a decrement in the heat transfer coefficients. 6. conclusions in the present work the heat transfer losses from the receiver to the surrounding with both addition and no addition of a half-cylindrical disc at the front of the receiver. the following points found: 1at our knowledge, this is the first study of its kind to this case. 2the addition of the shape modification cause a decrement in the heat transfer coefficient. 3the maximum decrement occurs at the case of 0 o orientation (i. e. the case of the collector facing the flow). 4the lowest decrement occurs at 90 o case, which is because the modification of shape works as guides of flow. 5the increase of the diameter ratio between the half-cylindrical disc and the receiver has a small effect on the heat transfer process. 6the shape improvement may be a good strategy to decrease the heat losses from the receiver. 7. references [1] al-ansary, hany, and zeitoun, o., "numerical study of conduction and convection heat losses from a half-insulated air –filled annulus of the receiver of a parabolic trough collector", solar energy, 85, pp. 3036-3045, 2011. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 233 [2] bejan a. convection heat transfer. new york: wiley; 2004. p. 178–83. [3] cheng, z. d., et. al., "numerical simulation of a parabolic trough collector with nonuniform solar flux conditions by coupling fvm and mcrt method", solar energy, 86, pp. 1770-1784, 2012. [4] cheng, z. d., et.al, "three-dimensional numerical study of heat transfer characteristics in the receiver tube of parabolic trough solar collectotr", international communications in heat and mass transfer, 37, pp. 782-787, 2010. [5] christ, farid c., "numerical modelling of wind and dust patterns around a full-scale paraboloidal solar dish", renewable energy, 39, pp. 356-366, 2012. [6] daniel, premjit, et. al., "numerical investigation of parabolic trough receiver performance with outer vacuum shell", solar energy, 85, pp. 1910-1914, 2011. [7] incropera fp, dewitt dp. introduction to heat transfer, sixth edition. john wiley & sons, inc; 2011. [8] kalogirou, soteris a., "a detailed thermal model of a parabolic trough collector receiver", energy, 48, pp. 298-306, 2012. [9] l¨upfert e, geyer m, schiel w, esteban a, osuna r, zarza e, et al. eurotrough design issues and prototype testing at psa. in: proceedings of asme international solar energy conferenceforum 2001. washington, dc: solar energy: the power to choose; april 21-25, p. 289–394. [10] hachicha, a. a., et.al. "numerical simulation of wind flow around a parabolic trough solar collector", print submitted to applied energy, november 20, 2012. [11] naeeni, m., and yaghoubi, m., "analysis of wind flow around a parabolic collector (2) heat transfer from receiver tube", renewable energy, 32, pp. 1259-1272, 2007. [12] naeeni n, yaghoubi m. analysis of wind flow around a parabolic collector (1) fluid flow. renewable energy an int j, submitted for publication. [13] padilla, ricardo vasquez, et. al., "heat transfer analysis of parabolic trough solar receiver", applied energy, 88, pp. 5097-5110, 2011. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 234 table (1): the specification of the euro trough solar collector (l¨upfert.2001) layout parabolic trough collector support structure steel frame work, pre-galvanized, two variants with light weight, low torsion collector length 12 m per element; 100 150 m collector length drive hydraulic drive max. wind speed operation: 14 m/s; stow: 40 m/s tracking control mathematical algorithm + angular encoder checked by sun sensor parabola y = x 2 /4f with f = 1.71 m aperture width (w) 5.8 m reflector 28 glass facets per sce absorber tube evacuated glass envelope, uvac® or other, application dependent fluid oil, steam, application dependent cost < 200 euro/m 2 table (2): details of adopted meshes for each pitch angle pitch angle 0 o 90 o 180 o number of element 90929 45765 31256 minimum mesh quality 0.6376 0.6111 0.6475 average mesh quality 0.9703 0.9724 0.97 tabe (3): the validation datas. position nua nufsp numax/pos numin/pos hachicha [4] 0 o 24.5 33.1 41.4/289.5 o 9.5/196.8 o present work 0 o 25.8 32.79 34.38/313.7 o 10.9/132.5 o hachicha [4] 90 o 47.4 86 86/0 o 27.3/222 o present work 9 o 48.3 67.7 69.8/22 o 19.99/204.8 o hachicha [4] 180 o 22.5 23.7 29.1/269.5 o 7.4/85.9 o present work 180 o 21.66 19.1 25.82/188.8 o 15.64/56.3 o hachicha [4] cylinder in cross flow 52.2 86 86.57/357.4 o 17.4/272.2 o present work cylinder in cross flow 47.4 45.37 45.37/360 o 17.16/207.9 o al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 235 figure (1): the orientations of the present work. figure (2): the suggested modification in the present work. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 236 figure (3): the trough collector case study. figure (4): computational domain of the wind flow study around an euro trough solar collector [hachicha. 2012]. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 237 figure (5): mesh quality around the mirror and hce figure (6): mesh quality around the hce (heat concentration element) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 238 figure (7): variation of average nusselt number and wind speed (a) 0 20 40 60 80 100 120 140 160 180 200 0 2 4 6 8 10 12 14 16 a v e ra g e n u ss le t n u m b e r (n u a ) wind velocity (m/s) nua-present work nua-eq.(7.45) [ incropera. 2011] al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 239 (b) (c) figure (8): temperature distribution around the ptc for different pitch angles: (a) θ=0 o , (b) θ=90 o , (c) θ=180 o al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 240 (a) (b) figure (9): variation of the local nusselt number around the hce for different pitch angles: (a) θ=0 o , (b) θ=90 o forced convection 0 5 10 15 20 25 30 35 40 45 50 0 50 100 150 200 250 300 350 lo ca l n u ss e lt n u m b e r angle (degree) without circal with circal dr=1.3 with circal dr=1.5 with circal dr=1.7 with circal dr=2 0 10 20 30 40 50 60 70 80 90 0 50 100 150 200 250 300 350 lo ca l n u ss e lt n u m b e r angle (degree) without circal with circal dr=1.3 with circal dr=1.5 with circal dr=1.7 with circal dr=2 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 241 figure (10): variation of the local nusselt number around the hce for pitch angles: (θ=180 o ) mixed convection. figure (11): variation of the average nusselt number around the hce with diameter ratio (dr). 0 5 10 15 20 25 30 0 50 100 150 200 250 300 350 lo ca l n u ss e lt n u m b e r angle (degree) without circal with circal dr=1.3 with circal dr=1.5 with circal dr=1.7 with circal dr=2 0 10 20 30 40 50 60 0.0e+00 1.3e+00 1.5e+00 1.7e+00 2.0e+00 a v e ra g e n u ss e lt n u m b e r diameter ratio θ=0o θ=90o θ=180o al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٢٩ nonlinear finite element analysis of reinforced concrete deep beams with opening abstract this research deals with nonlinear analysis of reinforced concrete deep beams with openings by three dimensional finite element method under static load. the constitutive models of the material nonlinearity are adopted to take into account the nonlinear stress-strain relationships of concrete and steel, such as (cracking and crushing of concrete, and yielding of reinforcement). a twenty-noded isoparametric brick element with sixty degrees of freedom is employed to model the concrete while the reinforcing bars are modeled as axial members embedded through the brick element with perfect bond. parametric study is considered to deal with the effect of opening location on the ultimate strength of deep beams. it was found that providing an opening at the shear zone causes sharp decrease in ultimate load by about (31%-56%) for simply supported deep beams. therefore, if the designer has to provide an opening in a deep beam, he should keep it far away from the load path. ����ب ا�������� ا������ ا������ ا���و�� �� ����ت �����ام � ��ا�����! ا� � &���� ا��%�$� ا����دة ا�� $� �� �� ��ت ا������� ا����� ا������ ��� ���ل '���& ت% �� ا���$ � #�ول ا� ��� ا��&��( /�0 /.-�� ا,+��ل ا�*�آ# &&=�ف ا��&&�دة )#;&&� ا: �&&�ر #&&3 /��8&& ا����&&�� /&&7 ا�&&6 ا��. ا��#�4&&� ا���&&3دة � &&��� وا��3�8a 3&&&& /&&<�@ و/?&&<7 b��* ��8 ا������ .ا��c��c�0 و+3�3 ا�� de�f�/ 7/ ��+ gدر h� � ذو <�� h �i3 و �k�(����mkن +3�&3 . ا��#=� ا� p&a /&�ا)o /&�م )� �k�(�����رة h�f ا��#��4 ا�a �&�ر /&.-�� p&k�a . #?�&� ا� *��0�8a b آ��a �4�#�ر��: �;�&0 درا�& 4� �� /=�ف ا�� ��ت ا����� و/7 ا�� eر إ��ا��&� ��m&#( 6 ا: r/ نs tu� � ه� ha أه7 ا���اa ا�� eا� pk�a إن ��=& ا��&z %.�?&� �&�ف /�&3ث ا���a3&#�% �e ، 7 #3 ا�&��#a �&% &� eن ا��&c/ &f &���( آ��&�ا � �=&k,3ار ا���& ا&��( ا:�#�د) %٥٦-%٣١(� ��ت ا����� ا��*���� . dr. ammar y. ali college of engineering university of babylon dr. nameer a. alwash college of engineering university of babylon khamail abdul-mahdii mosheer college of engineering university of al-qadisiya � ا+���ذ ا������ ا��آ�)ر ���ر ���� �� آ��� ا�,%��� ! � ��-�. ا���0ذ ا��آ�)ر ���� ��1 ا0-�� ��)ش آ��� ا�,%��� ! � ��-�. ����4! ��1 ا��,�ي -�2 -�.���� ه%��� -���� .�-�� ا���د���/آ��� ا�,%��� al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٠ the classical definition of a deep beam is the member which has a depth much greater than the normal in relation to its span, while the thickness in the perpendicular direction is much smaller than either the span or the depth. deep beams occur in engineering structures such as in bunkers and water tanks where the walls act as vertical beams spanning between column supports [khalaf,(1986), mahmoud,(1992)]. in some multistory buildings, it is often desirable to have the lower floors free of columns, therefore; these beams may be designed as beams spanning across the column free space. almost, these structures may include elements in the form of deep beams provided with openings for electrical cables, mechanical ducts and water and sewerage pipes (el-hashimy et al.,(1989)). aci-building code classified deep beams as those with span to depth ratio about (4) or less, or a shear span less than about twice the depth . shear and flexural behavior of deep beam the previous studies showed that reinforced concrete deep beams have behavior more complex and differ from that of shallow beams in many items: 1. in deep beams, the transverse sections which are plane before bending do not remain plane after bending (winter and nilson,(1978)). 2. the neutral axis does not usually lie at mid-depth and moves away from the loaded face of the member as the span to depth ratio decreases as shown in figure (1) 3. flexural stresses and strains are not linearly distributed across the beam depth (winter and nilson,(1978)). the flexural strength can be predicted with sufficient accuracy using the classical methods introduction notation al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣١ employed for beams of normal proportions. the equivalent rectangular stress block and associated parameters can be employed without change. experimental studies showed that shear strength of deep beams may be as much as (2-3) times greater than that predicted by using the expression for normal members (winter and nilson,(1978)). it is well known that shear transfer of diagonally cracked concrete beams of normal proportions takes place by four mechanisms: 1.direct transfer in the uncracked concrete compression zone. 2. aggregate interlocking. 3.dowel action of the flexural main reinforcement. 4.direct tension of the web reinforcement. for deep beams, however in addition to the items above, a significant amount of load is carried to the supports by compression thrust joining the load and the reaction (sanad and saka (2001)). diagonal cracks, which form roughly in a direction parallel to a line from load to support, isolate a compression strut, which acts with the horizontal compression in the concrete and the tensile force in the main reinforcement as a truss to equilibrate the loads (winter and nilson,(1978)). finite element analysis of reinforced concrete 1 three–dimensional brick element the quadratic twenty-node brick element shown in figure (2) are adopted to represent concrete. this type of element is popular due to its superior performance. a major advantage of the quadratic twenty–node brick element over the eighty–node brick element, when studying complex cases, is that less number of elements can be used, as well as it may have curved sides and therefore provides a better fit to curved sides of an actual structure [cook,(1974), moaveni,(1999)]. 2 shape functions the element has twenty nodes and sixty degrees of freedom and bounded by planes with ξ, η, and ζ = ± 1 in ξ, η, ζ space. the starting point for the stiffness matrix derivation is the element displacement field. the isoparametric definition of displacement components is: ∑ = = ∑ = = ∑ = = n 1i )wi,, ni( ),, w( n 1i )vi,,( ni ),, v( n 1i )ui,, ( ni ),, u( ζηξζηξ ζηξζηξ ζηξζηξ where ni (ξ, η, ζ) is the shape function at the i-th node and ui, vi and wi are the corresponding nodal displacements with respect to global x, y, and z coordinates. the shape functions of the quadratic twenty -node brick element are shown in table (1). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٢ 3 element stiffness matrix the tangential stiffness matrix of the three-dimensional isoparametric solid element is given by: edv d].[b][ ev .t[b]e]k[ ∫= by using the transformation product rule, the stiffness matrix becomes: ∫ + − ∫ + − ∫ + − ζηξ= 1 1 1 1 1 1 dddj]b][d[t]b[e]k[ …(3) 4 reinforcement idealization in developing a finite element model for reinforced concrete members, at least three alternative representations of reinforcement have been used: a) distributed representation b) discrete representation c) embedded representation 5 concrete model adopted in the analysis in this study, a plasticity-based model is adopted for the nonlinear analysis of threedimensional reinforced concrete structures under static loads. in compression, the behavior of concrete is simulated by an elastic-plastic work hardening model followed by a perfectly plastic response, which is terminated at the onset of crushing. the plasticity model in compression state of stress requires the following characteristics (chen,(1982)): 1.yield criterion 2.hardening rule 3.flow rule 4.crushing condition in tension, linear elastic behavior prior to cracking is assumed. a smeared crack model with fixed orthogonal cracks is adopted to represent the cracked concrete. the model will be described in terms of the following: 1.cracking criterion 2.post-cracking formulation 3.shear retention model 6 modeling of reinforcement compared to concrete, steel is a much simpler material to represent. its stress-strain behavior can be assumed to be identical in tension and compression. in reinforced concrete members, reinforcing bars are normally long and relatively slender and therefore they can be assumed to be capable of transmitting axial forces only. in the current study, the uniaxial stress-strain behavior of reinforcement is simulated by an elastic-linear work hardening model. ... (2) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٣ simply support reinforced concrete deep beams simply support reinforced concrete deep beams are analyzed using the computer program (p3dnfea). details of three deep beams tested experimentally by ramakrishan and anathanarayana (1968) are shown in figure (3). the first beam (a4) was subjected to two point loads located at the third portion of the beam, while the second (k2) was loaded with a uniform load and the thrid beam (k'1) was analyzed under one concentrated load applied at mid-span. due to symmetry of loading and geometry, only one half of the beam is analyzed using sixteen 20-node brick elements for the first beam and twelve 20-node brick elements for the second and third as shown in figure (4). the steel reinforcement is represented by embedded bar along span length. material properties of concrete and steel are given in table (2). figure (5) to figure (7) show the load-deflection response at mid-span of the beams. the computed response of load-deflection refers to good agreement with experimental result for most loading levels with difference in ultimate load about (3%), (2%) and (5%) for beams (a4), (k2), and (k'1), respectively. the cracking pattren of the beam for different load levels are shown in figure(٨). the first crack initiates at bottom surface of the middle zone of the beam at load (21.4%), (22.9%), and (22.1%) of ultimate load for the beam a4, k2, and k ' 1, respectively. the cracks develop in all three directions of the beam, throughout the increase in the loading levels. parametric study of simply supported reinforced concrete deep beams with openings simply supported reinforced concrete deep beams with openings are considered. all the openings with position and size are indicated by symbols, which are ranging from b0 to b10 as explained in figure (٩) and table (3). two openings are provided in each beam symmetrically about the mid-span except (b6, b7, b8, b9, b10) that has only one opening at mid-span, and b0 that is solid without opening. area of each opening is equal to (4%) of the side view area of the beam. due to symmetry of loading and geometry, only one half of the beams is analyzed as shown in figure(١٠). material properties of the concrete and steel are given in table (4). a parametric study is presented including the influence of opening location along the beam span and through the depth . to explain the effect of openings on the behavior of deep beams, the openings are provided at different positions along beam span and throught depth. these figures illustrate that the effect of an opening on the ultimate load depends on the extent to which it interrupts the load path joining the bearing block at the load and reaction points. presence of openings in the shear zone of a deep beam leads to reduce considerably the ultimate load as shown in figure (1١). the ultimate load in beams b1, b2, and b3 is about (31%, 49%, and 38%) less than that of the case of no opening of similar solid beam b0, respectively. in beams b4 and b5, the reduction in ultimate load is about (40% and 56%) of the solid beam b0, respectively, where the openings completely interrupted the load path, therefore; serious strength reduction occurred as shown in figure (1٢). ultimate load in beams b6 and b7, at which there is one opening made in the beam center and far away from the load path , is about (8% and 19%) less than that of b0, respectively. on the other hand, for b8 the opening piercing the critical shear zone, ultimate load is about (39%) less than that of b0 as shown in figure (1٣). in beams b9, and b10, the openings are provided in mid-span and are reasponsably clear from the load path, figure (1٤) shows that their ultimate loads were comparable to that of solid beam b0 with a difference about (13%). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٤ conclusions on the basis of the analysis carried out by using three-dimensional nonlinear finite element method with p3dnfea computer program, the following conclusions can be made: 1. the effect of opening on the ultimate load of deep beams depend primarily on the extent to which it intercepts the ‘load path’ and on the location at which this interception occurs. therefore, if the designer has to provide an opening in a deep beam, he should keep it far away from the load path. 2. providing an opening at the shear zone causes sharp decrease in the ultimate load by about (31%-56%) for simply supported deep beams 3. presence of openings in the critical shear zones of deep beams leads to reduce considerably the ultimate load more than that in flexural zone by about (34%). references 1. american concrete institute, “building code requirements for reinforced concrete”, detroit, aci-381-02. 2. chen, w.f., (1982), “plasticity in rinforced concrete”, mcgraw-hill, inc, new york. 3. cook, r.d., (1974), “concept and application of finite element analysis”, john wiley and sons, inc., new york. 4. el-hashimy. h., naser. m., and farahat. a., (1990), “cracking load of reinforced concrete deep beams with openings”, convention paper. 5. khalaf, i.m., (1986), “nonlinear finite elements analysis of reinforced concrete deep beam”, m.sc. thesis, university of mosul. 6. moaveni, s., (1999), “finite element analysis theory and application with ansys”, prentice-hall, inc., new jersey. 7. ramakrishan, v., and anathanarayana, y., (1968), “ultimate strength of deep beams in shear”, journal of aci, vol. 65, pp. 87-98. 8. sanad, a., and saka, m.b., (2001), “prediction of ultimate shear strength of reinforced concrete deep beams using neural networks”, journal of structural engineering, asce, vol. 127, no. 7, july, pp. 818-828. 9. winter, g., and nilson, a.h., (1978), “design of concrete structures”, 9 th edition. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٥ table (1): shape functions of the quadratic 20-node brick element (cook,(1974)) location ξ η ζ ni (ξ, η, ζ) corner nodes ± 1 ± 1 ± 1 (1+ ξ ξi)(1+ η ηi)(1+ζζi) (ξ ξi+ η ηi + ζ ζi-2 )/8 mid – side nodes 0 ± 1 ± 1 (1ξ2)(1+ η ηi )(1+ ζ ζi ) /4 mid – side nodes ± 1 0 ± 1 (1η2 )(1+ ξ ξi)(1+ ζ ζi )/4 mid – side nodes ± 1 ± 1 0 (1ζ2 )(1+ ξ ξi)(1+ η ηi )/4 table (2): material properties and additional parameters of deep beams al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٦ size position beam no. open no. a1 a2 k1 k2 b0 b1 1 0.2 0.2 0.2 0.1 b2 2 0.2 0.2 0.4 0.1 b3 3 0.2 0.2 0.6 0.1 b4 4 0.1 0.4 0.45 0.05 b5 5 0.4 0.1 0.3 0.15 b6 6 0.2 0.2 0.4 0.4 b7 7 0.1 0.4 0.45 0.3 b8 8 0.075 0.53 0.481 0.235 b9 9 0.4 0.1 0.3 0.45 b10 10 0.53 0.075 0.235 0.481 table (4): material properties and additional parameters of simply supported deep beams with openings table (3): open notations al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٧ figure (1): distribution of flexural stresses in homogeneous simply supported deep beam c t=0.75wl 0.67h 0.5h l c t=0.2 wl 0.62h 0.5h l c t=0.38wl 0.67h 0.4h l c t <0.2 wl >0.16 wl > 0.62 l < 0.78 l 0.28l l l/h=4 l/h=2 l/h=1 h>l h=l/4 h=l/2 h=l w al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٨ figure (2): linear and quadratic isoparamatric solid element (hinton,(1988) ζ ξ η z x y 1 3 2 8 7 6 5 4 η ξ ζ y x z 20 12 11 10 9 8 7 6 5 4 3 2 1 19 18 17 16 15 14 13 (a): linear 8-noded element (b): quadratic 20-noded element 812 1-ø25 508 beam k2 78.5 812 1-ø25 38 1 beam k ' 1 81. p 812 1-ø25 762 beam a4 note: all dimentions in mm p/2 p/2 76.2 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٣٩ figure (4): finite element idealization of half of the simply supported deep beams beam k2 beam k'1 p/4 p/2 p/4 p/8 p/4 p/8 beam a4 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٠ p/2 p/2 p/2 0.0 0.1 0.2 0.3 0.4 deflection(mm) 0 60 120 180 240 300 360 l o a d ( k n ) experimental (1968) present study figure (5): load-deflection curve at mid-span for (a4) deep beam figure (6): load-deflection curve at mid-span for (k2) deep beam 0.0 0.1 0.2 0.3 0.4 deflection (mm) 0 50 100 150 200 250 l o a d ( k n ) experimental (38) present study al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤١ figure (7): load-deflection curve at mid-span for (k ' 1) deep beam 0.00 0.10 0.20 0.30 0.40 deflection (mm) 0 40 80 120 l o a d ( k n ) experimental (38) present study p 21.4% of failure load 22.1% of failure load failure load beam a4 failure load 22.9% of failure load beam k2 failure load beam k ' 1 sٍingle crack at gauss point double crack at gauss point figure (8): cracking patterns of simply supported deep beams al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٢ figure (9): simply supported deep beams with openings notice: all dimentions in mm 76.2 h =762 a2 l a1 h k2l k1h 2-ø20 254 254 254 p/4 p/8 p/8 figure (10): finite element idealization of b0 p/2 p/2 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٣ figure (12): load-deflection curve at mid-span for deep beams (b0, b4, and b5) figure (11): load-deflection curve for at mid-span for deep beams (b0, b1, b2, and b3) 0.00 0.10 0.20 0.30 0.40 deflection (mm) 0 90 180 270 360 l o a d ( k n ) b 0 b 1 b 2 b 3 b 1 b 2 b 3 b 0 0.0 0.1 0.2 0.3 0.4 deflection (mm) 0 60 120 180 240 300 360 l o a d ( k n ) b 0 b 4 b 5 b0 b4 b5 b 0 b 4 b 5 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٤ figure (14): load-deflection curve at mid-span for deep beams(b0, b6, b9, and b10) 0.0 0.1 0.2 0.3 deflection (mm) 0 60 120 180 240 300 360 l o a d ( k n ) b 0 b 6 b 7 b 8 b6 b7 b0 b8 0.0 0.1 0.2 0.3 0.4 deflection (mm) 0 60 120 180 240 300 360 l o a d ( k n ) b0 b6 b9 b10 b6 b9 b0 figure (13): load-deflection curve at mid-span for deep beams (b0, b6, b7, and b8) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 183 productivity estimation model for bracklayer in construction projects using neural network gafel kareem aswed email: gafelkareem@gmail.com assistant lecturer/ college of engineering/ university of kerbala/iraq received 17 december 2015 accepted 31 january 2016 abstract construction labour productivity is a major determinant of success of a construction project. time and cost overruns of construction projects are widely attributed to poor productivity of construction labour force. though considerable research exists on productivity factors in other countries, very little studies have addressed productivity issues in iraq. brainstorming session and site interview survey was conducted in karbala province in iraq, to identify the productivity and the factors affecting bricklayer labor productivity. thirteen influencing factors are utilized for productivity forecasting by artificial neural network (ann) model, and they include age, experience, gang health, gang number, weather, wages, site condition, material availability, wall length, wall thickness, wall height, mortar type, and security in site. one ann prediction model was built for the productivity of bricklayer labors. it was found that the predict productivity approximately the same as the actual productivity with a good degree of accuracy of the coefficient of correlation (r=86.28%), and mean square error (mse) of (1.32%) after testing the network. the developed ann model can be used dependably for estimating production rates of bricklayer for any building construction project by incorporating the influence of selected factors. kewords: production rates, artificial neural network (ann), construction project, labor productivity, bricklayer labors, modeling. في المشاريع االنشائية باستخدام الشبكات العصبية بالطابوق بنّاءال نتاجيةأتخمين ل بناء نموذج أسود غافل كريم email: gafelkareem@gmail.com قسم الهندسة المدنية -لهندسةا كلية–جامعة كربالء مدرس مساعد/ :مستخلصال ضعف أو قلة انتاجية القوى العاملة أحد أهم أسباب ة عامل البناء من العوامل المهمة في تحديد نجاح المشروع اإلنشائي وأنإنتاجي بالرغم من وجود عدد ال بأس به من الدراسات حول االنتاجية .التأخير في زمن التنفيذ وزيادة التكلفة في اغلب المشاريع اإلنشائية mailto:gafelkareem@gmail.com mailto:gafelkareem@gmail.com al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 184 يد ولتحد .يها في بلدان عديدة، فأن عدد قليل جداَ من هذه الدراسات حول موضوع اإلنتاجية قد اجريت في العراقوالعوامل التي تؤثر عل جلسة للعصف الذهني تلتها مقابالت شخصية في مواقع العمل أجريت اإلنتاجية والعوامل المؤثرة على انتاجية عمال البناء بالطابوق العمر، الخبرة، الحالة :ثالثة عشر عامال من العوامل الهامة في التنبؤ باإلنتاجية وتضمنت في محافظة كربالء وتم تحديد المختلفة الصحية للعمال، عدد العمال، الحالة الجوية، طريقة دفع األجور، ظروف موقع العمل، توفر المواد، طول الجدار، سمك الجدار، ارتفاع تم بناء نموذج )موديل( واحد باستخدام الشبكات العصبية االصطناعية .موقع العملالجدار، نوع المادة الرابطة وأخيرا توفر األمان في وبدرجة االنتاجية التي تم الحصول عليها من )الموديل( مساوية تقريبا لألنتاجية الفعلية قد وجد ان بالطابوق و للتنبؤ بإنتاجية عمال البناء . ( بعد تدريب وفحص الشبكة العصبية االصطناعية%1.32مربع الخطأ )( ومعدل %86.28)مقداره بمعامل ارتباط جيدة من الدقة 1-introduction the output to the input ratio is the general definition of the productivity, which is widely studied. the success of construction project is completely related to the labour productivity [anu & sudhakumar 2013]. too many factors that affect the productivity of construction tasks because it includes long sequential operations, workmanship, materials and tools, and variable conditions of project site. some of the factors are readily identified and others may not. in addition, it is difficult to restrict the effect of these factors on the productivity. determination of both qualitative and quantitative factors affecting the labor productivity on site such as weather condition, labor proficiency, equipment and material shortage, site conditions, project location, number of workers, etc. are widely researched [makulsawatudom et al., 2004] and [jiukun et al.2009)]. many prediction-modeling techniques have been used in the last ten years such as “statistical model, action response model, factor model, linear regression model etc.” [oduba, 2002]. even in developed countries, there are still many obscure productivity problems that in need to be further explored in spite of that the many researchers have been explored and tested the factors that affect the productivity [makulsawatudom and emsley, 2003]. it has been identified that the accurate prediction of production rates under any specific condition could be achieved using ann modeling technique, which has the dynamic learning mechanism with effective recognition capabilities. this research, therefore, aims to predict the bricklayer productivity in iraqi construction projects using ann. 2-research objective developing ann model for estimating the bricklayer (builder) productivity taking into account the influencing factors is the main objective of this study. 3-research justification the causes that stand behind the dependence of this study are: 1. production rates estimation of future projects depend on previous projects with readjustment for the various site factors and conditions influencing the builder productivity. 2. there is no standard production rates measurement system for bricklayer productivity. 3. modeling techniques to estimate the production rates are most reliable and accurate estimation. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 185 4-the research hypothesis the research hypothesis is “artificial neural network (ann) model is a strong modeling technique to estimate the productivity of bricklayer (builder) when using some factors as predictors”. 5artificial neural network (ann) artificial neural network (ann) achieved more reliable results than many developed modeling techniques for predicting labor production rates when incorporating the effect of different factors [sana et al. 2011]. input, hidden and output which is arranged in sequence layers along with the connectivity between them are the main components of the ann. input layer in the ann receives data from the outside world with their initial weights passed into hidden layers, which has no connectivity with outside world, to the output layers [zayed and halpin , 2005]. typical feedforward ann consist of several neuron in their layers linked together with connection weights as shown in fig. (1).the number of required values to predict is the issue that decide the number of neuron in the output layer of the ann. the input and hidden layer contains bias value that is due to absence of some input factors. ann has the capability to infer meaning from intricate or inaccurate data. complex patterns and trends detection which is not verified by other humans or computer techniques are analyzed with ann. it is important to have enough, reliable and accurate data for the successful implementation of ann. depending on the situation, the ann has the ability to change their status by what it learns from provided experience and examples. ann’s resembles computer programs, which stimulate the biological structure of the human brain in obtaining and storing knowledge by the learning process. the ann procedure is receiving the inputs through neurons and combine their weights together [tayfur, 2012].thousands of cycles from inputs and outputs data are presented to the ann at the training stage of the network. inputs are the issue factors and outputs are its solution. at the end of each training cycle, the error between the real and coveted output will be evaluated by the network. according to the selected training algorithm, this error is used to update the values of the connection weights. learning and generalization of the problems in the ann models could be achieved in spite of incomplete or erroneous data. the data used to test the prediction capability of the network is selected from the total data set. after a predetermined number of iterations, the network training and testing is stopped whereas no amelioration is done in the output. the output of one neuron is the input to the next layer neurons, which is mathematically represented as in equations (1) and (2) [ming et al., 2000]. ij=σwjixi+θj (1) yj=f(ij) (2) a different type of neural network model and learning procedure were founded multilayer perceptron (mlp) neural network with back propagation algorithm is adopted in this research which is most important ann. it consist from input layer with multiple input factors of linear function, hidden layer, al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 186 and output layer with nonlinear activation function to calculate single output ( productivity). random values are set to the weights at the start of training of ann and the interconnecting weights are updated until the overall error is reduced. mlp could be used when we have no definite information about the relationship between the input and the output. the activation function used in this study is tanh function: f(x) = tanh(x) (karlık and olgac, 2011). 5-1 applications of anns in productivity estimate ann has many applications in construction management especially in labor productivity forecasting. ming et al., 2000 improved jason 1996 model, which is a probability inference neural network (pinn) to predict the productivity of formwork activity. the pinn was tested on real historical productivity data at a local construction company and compared with the classical feed forward back-propagation neural network model. abourizk et al. (2001) developed a predicted model for labor productivities of welding and pipe installation in industrial construction activities. moseley et al. (2005) studied the impact of change order on labor productivity using neural network model. samer and lokman (2006) identifying the factors affecting concreting activities using questionnaire survey and to develop the labor productivity neural networks. moselhi and khan (2010) studied the effect of a number of factors on labour productivity such as temperature, relative‐humidity, wind speed, precipitation, gang size, crew composition, height of work, type of work and construction method employed using the neural network modeling. temperature, height, and the work type were found the most factors of considerable effect on productivity. sana et al. (2011) studied the factors that might be affected the productivity rates of column concreting through direct measurement from site work in malaysia using the neural network model with minimal errors. sawsen and ali (2011) developed ann model to estimate the ceramic productivity of walls in iraq. five input factors were used as independent variables, which is ganger experience, ganger age, number of assistant labors, area of ceramic tile, site complication, height level of the work, and weather condition. it was found that height level of the work is the most significant effect on the predicted total productivity. al-zwainy et al. (2012) developed ann model to estimate the productivity of marble floor finish in iraq. ten factors were used as influence factors which is: age, year, experience, number of the labor, floor height, tiles size, the security conditions, the work team health, weather conditions, site condition, and the availability of construction materials. the most important factors in estimating the productivity of marble floor finishing works is; the age, experience and number of assist labor. mady (2013) trained many neural network models and he found that the generalized feed forward (gff) model was the best one in predicting the labor productivity for casting concrete slabs for formwork in gazzapalestine. heravi and eslamdoost (2014) developed an artificial neural network models to measure and predict labor productivity in developing country of iran. they investigated the influential factors on labor al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 187 productivity using the bayesian regularization and early stopping methods. their work involved in installing the concrete foundations of gas, steam, and combined cycle power plant construction projects. the developed models are implemented at two real power plant construction projects. in this research the effect of different factors on production rates of bricklayer, as a single activity, has been taken into account to produce more accurate ann model. 6research methodology to achieve the objective of the study, the below mentioned methodology is adopted 6-1 data collection the previous studies have been identified many factors that have been influencing the labor productivity at site. brainstorming session has been made to select the most important factors. out of forty-five invitations issued, thirty-two participants from different agencies in karbala province related to construction projects are accepted to implement the brainstorming session. they told what the aims of the session are before they come to it, so that they can start to think about possible contributions to the problem under discussion. these participants are divided into two groups of diverse and relevant backgrounds, asked (based on their local experience) to write down the parameters that they expect to be used as predictors of the bricklayer production rate of construction projects. after screening the brainstorming session results, it is found that the variables, which might affect the bricklayer productivity of construction projects, are age, experience, gang health, gang number, weather, wages, site condition, material availability, wall length, wall thickness, wall height, mortar type, and security in site. two classes of independent variables are found: objective and subjective variables. the measurable (objective) variables according to their unit of measure, such as age and experience are measured in years, gang number is measured in number, wall thickness is measured in centimeters, and wall length is measured in meters. coding system is used to measure the qualitative (subjective) variables, for example, the gang health can be classifies to bad moderate and good and assigns them the value 1, 2 and 3 respectively. on site interviews have been carried out among (32) builders to gather (118) cases of production rate of bricklayer. respondents are required to write down the factor under which he can achieve the specific production rate as shown in fig. (2). 6-2 modeling software neurosolutions version 6.0.0 is used in this study, which works in microsoft excel as shown in fig.(3). neurosolutions is easy to use, powerful and flexible software [neurodimension, inc., 2014]. at the beginning, data should be arranged in microsoft excel. excel toolbar “neurosolutions” is added to build and design the model. neurosolutions software is based on columns called input and output column. comparison is made between the obtained results from these columns. input and output column should be assigned before the training process of the ann. then, data sets of training, cross validation, and testing should be prepared. these data sets are separated in default percentages or as the user wish option. the results is presented for each function and the graphics automatically reflecting the values of the functions. different type of neural network are founded but multilayer al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 188 perceptron (mlp) neural network is used. the system was designed as to have three hidden layers having same features. tangent axon is chosen as the activation function for both hidden and output layer. constant learning rate parameter of (0.1) and momentum term factor of (0.7) are used during the training of network. the mean square error (mse) at 1000 epochs is calculated during training. 7model development thirteen valuable factors, as described in earlier section, in need for thirteen (13) input neurons in the first layer of the ann.trial and error has been done to detect the number of neurons in a single hidden layer. it has been found that the (3) neurons showed least error. maximum convergence is achieved in (1000) epochs. gradient decent with momentum backpropagation with hyperbolic tangent sigmoid transfer function is used as a learning algorithm. learning rate of (0.1) and (0.7) momentum term factor values is used in model development. mean square error (mse) has been calculated to check the model accuracy as in the equation (3) below (battaglia, 1996): = (3) it is the difference between the observed data and calculated by the ann model responses for all data in the training set to check how well the network outputs fit the data. batch method is used for weights updating in the (1000) epochs. both of the output and hidden layer is of tanh-sigmoid activation function. the test results are shown in table (1), and fig. (4) and (5).the mse and r training and cross validation phases are calculated. the best value of r is (0.8628) accompanied with small values of mse equal to (0.0074) and (0.0269) for the training and cross validation phases respectively. tanhhyperbolic function is found the best activation functions for both hidden and output layer. the actual productivity compared with estimated productivity for cross validation data set is shown in fig. (6). it is noted that there is a slight difference between two productivity lines except for exemplar seven and ten. 7-1 sensitivity analysis of the ann model inputs sensitivity analysis was carried out by neurosolution tool to evaluate the influence of each input parameter to output variable for understanding the significance effect of input parameters on model output. the sensitivity analysis for the best ann model was performed and the result is summarized and presented in fig. (7). it can be seen from fig. (7) that the wall thickness (x10) parameter has the greatest effect on the productivity output where its influence exceeds the impact of other factors combined. the value (180) for the wall thickness input parameter is the value of the standard deviation for output values. these output values are recorded after training the model with fixing the best weights on a matrix data. all inputs are fixed on the mean value for each raw except the wall thickness value which varied between (the mean – standard deviation) to (the mean + standard deviation). it is clear that the productivity increased along with the wall thickness increase. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 189 the gypsum mortar type (x12) and the lump sum wage payment method (x6) ranked second and third respectively. gang number (x4) and sunny weather (x5) has the fourth and fifth sensitive factor. it is clearly from fig. (7) that the remaining parameters have low impact on the output (productivity). 7-2 model formulation the resulted equation is too long as shown in fig. (8), so program named formula wand is used to get the connection weights of the neural network from neurosolutions software in excel or vba as shown in fig.(9). the researcher built the required equation model using excel programmed sheet. only input data is required in the programmed excel to predict production rate automatically and the results appeared in column named predicted production as shown in fig. (10). 7-3 model validation one of the most important steps in developing any model is to test its accuracy and validity. this process is also refers to as the model validation. it involves testing and evaluating the developed model with some test or validation data. the validation data should be some representative data from the targeted population but have not been used in the development of the model. in this study, the validation data are extracted from the same historical data file. they are not a part of the data used in the development of the model. the predicted productivity of these twelve cases computed using the model equation are compared with real data records (observed) and the results of this comparison are shown in table (2). plotting the observed vs. the predicted values of productivity which is showing r=83.27% and r 2 =69.35% for cross validation test set. it gives a good agreement between the actual and predicted values draws a 45-degree line, which means that the actual productivity values are approximately similar to the predicted ones and indicates a reasonable concentration of the predicted values around the 45-degree line as shown in fig. (11). 8-conclusions the measurement of bricklayer production rates in construction projects, which is the main goal of this research, is achieved successfully. the developed ann model has predicted the production rates of bricklayer accurately with least error. it is found that the wall thickness parameter has the greatest effect on the productivity output. it has been also found out that the lump sum wage payment method and the gypsum mortar type are extremely correlated with the production rates of bricklayer at sites. the developed ann model predicted reliable values of production rates of bricklayer by incorporating the influencing factors. the mse of the developed ann model, which is the measure of model performance, to predict production rates of bricklayer has been determined. from the above-mentioned findings, it can be concluded that the developed ann model can be used dependably for estimating production rates of bricklayer for any building construction project by incorporating the influence of selected factors. the performed sensitivity analysis was in general logically where the wall thickness, mortar type, and wage payment had the highest influence, while gang number, weather, gang health, wall length, wall height, and age respectively has moderate effect on productivity. therefore, it can be said that the al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 190 variability of builders production rates are due to the considerable effect of the influencing factors at the sites. surveyors can be easily used the proposed excel sheet to predict the bricklayer production rates in order to estimate the required time for brick work activity in bidding new jobs. 9recommendations 1. other neural network models for plastering, tiling, painting and other construction works should be performed. 2. government agencies and engineering associations are recommended to establish a database for executed projects for researchers to develop productivity estimation process. 3. contractors should be encouraged to keep historical data of productivity study in finished projects to improve the effectiveness and accuracy of estimation for future projects. 10-limitation the research limitations are: 1. the data is collected from builders in karbala construction projects during summer 2015 other provinces, adjustment may be needed. 2. actual production rates, by observing new project site, should be collected to evaluate the model results. referances [1] abourizk, s., knowles, p. and hermann, u.r. (2001) “estimating labor production rates for industrial constriction activities”, journal of construction engineering and management, vol. 127, no. [2] al-zwainy, faiq mohammed sarhan, rasheed,hatem a. and ibraheem, huda farhan (2012) “development of the construction productivity estimation model using arteficial neural network for finishing works for floors with marbile” arpn journal of engineering and applied sciences, vol. 7, no. 6, pp. 714-722. [3] anu v. thomas & sudhakumar j. (2013) “critical analysis of the key factors affecting construction labour productivity –an indian perspective”, international journal of construction management, 13:4, 103-125. [4] battaglia, g.j. (1996) “mean square error), amp journal of technology vol. 5 june, pp. 31-36. 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[9] karlık, b., & olgac, a. v., “performance analysis of various activation functions in generalized mlp architectures of neural networks” international journal of artificial intelligence and expert systems,vol. 1(4), 2011,pp. 111–122. [10] mady, mohammed (2013),” prediction model of construction labor production rates in gaza strip using artificial neural networks” master thesis in civil engineering, islamic university, gaza, palestine. [11] makulsawatudom, a., emsely, m. and kuldej. (2004). “critical factors influencing construction productivity in thailand” the journal of kmi tnb, vol. 14,no 3 july-sept 2004. [12] ming lu, s.m. abourizk and ulrich herman. (2000) “estimating construction productivity using probability inference neural network”, journal of computing in civil engineering, vol. 14, no. 4. [13] moselhi, o, khan, z (2010) analysis of labour productivity of formwork operations in building construction. “construction innovation”, 10(3), 286-303. 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(2006). neural networks for estimating the productivity of concreting activities. journal of construction engineering and management, vol. 132, no. 6, june 1, 2006. http://www.neurosolutions.com/documentation/neurosolutions_infinity.pdf al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 192 [19] sana muqeem, arazi idrus, m. faris khamidi, jale bin ahmad, saiful bin zakaria (2011) “construction labor production rates modeling using artificial neural network”, journal of information technology in construction (itcon), vol. 16, pg. 713-726. [20] sawsan rasheed mohammed and ali sabri tofan, (2011) “ neural networks for estimating the ceramic productivity of walls” journal of engineering, no. 2, vol.17,p.p 200-217. [21] tayfur, g. "soft computing in water resources engineering." © wit press (2012), sbn:978-184564-636-3. [22] zayed ,tarek m. and halpin ,daniel w. (2005) “pile construction productivity assessment.”, journal of construction engineering and management, asce 073-93644. table (1): training report of ann model training cross validation best networks 1 2 run # 1000 3 epoch # 0.007426251 0.013235436 minimum mse 0.007426251 0.026911242 final mse -------0.862862782 r table (2): comparison of predicted and observed productivity case no. 1 2 3 4 5 6 7 8 9 10 11 12 observed 3000 2000 1000 2500 2000 900 2000 1700 1000 2200 1900 1100 predicted 2710.045 1833.888 759.664 2869.506 2184.749 1111.471 3183.341 1906.771 1633.732 2998.397 2393.752 833.079 figure (1): artificial neural network structure (haykin, 1999). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 193 figure (2): productivity questionnaire form al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 194 figure (3): neurosolutions software version 6.0 (neurodimension, inc., (2014). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 195 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 196 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 197 figure (8) : output formula al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 198 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 199 r² = 0.6935 900 1400 1900 2400 2900 3400 3900 800 1300 1800 2300 2800 3300 p re d ic te d observed productivity figure (11): observed vs. the predicted values of bricklayer productivity microsoft word 2.doc ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١ باستخدام طريقة المسماريةمقارنه بين التبريد التصادمي والتبريد األفقي للزعانف تولد العشوائيه حيدر شاكر عبداهللا. د جامعة القادسية-كلية الهندسة قسم الهندسة الميكانيكية الخالصة ∆p من انتقال الحـرارة وهبـوط الـضغط الناتجة الثرموديناميكية الخسائر العشوائية كوسيلة لقياس تولد تم استخدام طريقة ساعد فـي جعـل التـأثير , أن استخدام هذه الطريقة .)عمودي( مبرده بشكل تصادمي الشكل هلمجموعة زعانف مسمارية اسطواني تم الحصول على تعبيـر . لألمثليةobjective function وهبوط الضغط واضح في دالة الهدف rللمقاومة الحرارية المشترك وبتطبيـق معـادالت حفـظ الكتلـة c.v مجموعة الزعانف داخل حجم التحكم إنوذلك بتخيل عام لمعدل تولد العشوائية رياضي ت كذلك تم استخدام معادالت تحليلية وتجريبية لحـساب معـامال .entropy الموازنة بين الطاقة والعشوائية إلى باإلضافةوالطاقة وسرعة الدخول characteristic lengths استخدام ابعاد مميزه جديدهحيث تم , cd واالعاقةf واالحتكاك hانتقال الحرارة auكسرعة مصدر reference velocity رينولد إعداد في حساب re تم استخدام طريقة . وهبوط الضغطsumt لألمثلية تم برمجـة اسـلوب " ايضا .والتي تستخدم متجهات المشتقة األولى نحو اقل قيمة لدالة الهدف والتي تمثل العشوائية في هذا البحث حيث كانت القيود مأخوذه من التصاميم الشائعة األسـتخدام c++باستخدام لغة constraintsاألمثلية المقترح لدالة الهدف والقيود ، حيث تم التصميم لمجموعة زعانف مسمارية اسطوانية الشكل موضوعة على لوحة الكترونية سمكها في الدوائر األلكترونية الدقيقه mm2 ومعدل توليدها للحرارة هوw10مقدارها ة حرارة جو بدرجk300. نتائج التبريد األفقي لسرع هـواء تم مقارنة النتائج مع .واقطار زعانف مختلفه a comparison between impingement and horizontal cooling of pin-fin by using entropy generation method dr. hayder shakir abdulla college of engineering-al-qadisiyia university mechanical engineering departments abstract the entropy generation method is applied to measure the thermodynamic losses caused by heat transfer and pressure drop in cylindrical pin-fin heat sinks which cooled by impingement air flow. the use of this method allows the combined effect of thermal resistance and pressure drop to be assessed through the simultaneous interaction with the heat sink. a general expression for the entropy ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٢ generation rate is obtained by considering the whole heat sink as a control volume and applying the conservation equations for mass and energy with the entropy balance. analytical and empirical correlations for heat transfer coefficients and friction factors are used in the optimization model, where a new characteristic lengths are used and reference velocity used in reynolds number and pressure drop. the sumt method is used to optimize the model which use the directional derivative to reach the minimum value to the objective function which is the entropy generation rate in this research. the ++c language is used to programming the optimization procedure to the objective function and its constraints which is taken from the general electronic package case. the design is performed on the electronic circuit of mm2 thickness which is generate w10 in the 300k ambient temperature. a comparison between the results and the results of the horizontal cooling is accomplished for the different air velociti nomenclatureالرموز املستخدمة a للصفيحة األساسالمساحة الكلية base plate ، wl،2m bpa ،2المساحة الخالية من الزعانف 4 dnwl π −، 2m ca ،2مساحة مقطع زعنفة واحدة 4 d π ،2m fina ،المساحة السطحية لزعنفة واحدةhd2 4 π ،2m hsa 2انف، المساحة السطحية لجميع الزعm d ،قطر الزعنفةm f االحتكاكمعامل )(xci قيودconstraintsطريقة األمثلية h ارتفاع الزعنفة ،m h ،معامل انتقال الحرارة بالحملkmw ./ 2 i لقيود طريقة األمثليةعداد k ،الموصلية الحراريةkmw ./ l الجريانباتجاهالصفيحة األساس طول ،m n العدد الكلي للزعانف في المجموعة n عدد متغيرات التصميمdesign variables ln الجريانباتجاه األفقيةعدد الصفوف tn عدد الصفوف العمودية على الجريان q الصفيحة األساس خالل الحرارةالنتقالالكلي معدل ال ،w r ،المقاومة الحراريةwco / dre على اساس القطرعدد رينولد ،ν/. aud lre ،عدد رينولد على اساس الطولν/. aul . s kw، معدل تولد العشوائية / ls باتجاه الجريان، وأخرىالمسافة بين زعنفة m ts على الجريان، يدعمو باتجاه وأخرىبين زعنفة المسافة m t ،درجة الحرارة المطلقةk ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٣ au الداخل لمجموعة الزعانف، الهواء سرعة sm / maxu ئع القصوى خالل اقل مساحة جريان خارجي، سرعة الماsm / ix متغيرات التصميم الرموز الالتينية p∆ ،هبوط الضغطpa δ الصفيحة األساسسمك ،m γ ،نسبة النحافةdh / µ ،اللزوجة المطلقةspa. ν ،اللزوجة الكيناماتيكيةsm /2 ρ ،3آثافة المائع/ mkg الرموز الدليلية السفلية a الهواء bp صفيحة األساس c التماس w الجدار f المائع fin زعنفة مفردة hs مجموعة الزعانف m المادة المصنوعة منها الزعنفة او البعد المميزoptimumالحالة المثلى * introductionالمقدمة من األمور الـضرورية لتحـسين األداء الكلـي للـدوائر أصبح heat sink اختيار مجموعة الزعانف إن إن. الحديثـة األجهـزة نحو الصغر في يتجه حجمها إن، حيث cpu في الحاسوب جلمعالكا المعقدة االلكترونية فـي " في العقود األخيرة وخاصـة بالزيادة بداء الدائري ذات المقطع المسمارية الزعانفتطبيق مصفوفات من من كون انتقال كفاءة مجموعة الزعانف المسمارية يأتي إن. microelectronics الماكروية االلكترونيةالدوائر اسسو bejan (1982)و poulikakos الباحثان . cross flowالحرارة فيها بطريقة الحمل بالجريان المتقاطع الحمـل ظـروف على جعل العشوائية اقل مايمكن تحت باالعتماد األبعاد المثلى للزعنفة إليجادالطريق النظري ثم اسـتخدموا هـذه general finلزعنفة عامه د العشوائية لمعدل تول اشتقوا عالقة رياضية أنهمحيث .القسري إلـى باإلضـافة لزعانف على شكل صفيحة ذات مقاطع مستطيلة، شبة منحرفة، األبعاد المثلى الختيارالمعادلة .زعانف مثلثة مستطيلة المقطع ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٤ تنتاج ان الجـزء درسا التبريد التصادمي بشكل عملي حيث تم اس )durbin١٩٩٢( و hollworthالباحثان اما بالنسبه للجزء االكبر من انتقال الحرارة فانه , jet orificesاالكبر من هبوط الضغط يكون عند فتحات البثق .spent air خروج الهواء فتحةسيكون عند علـى جعـل باالعتمادلمصفوفات الزعانف وثقوا األشكال المثلى )١٩٩٣ (moregaو bejanالباحثان باعتبارها كوسط صفوف الزعانف نمذجوا أنهمحيث . بين المائع ومادة الزعنفة اقل مايمكن rة الحرارية المقاوم .بشكل البعدي rc مقاومة التماس الحرارية حيث تم التعبير عن darcy مسامي بتطبيق معادلة دارسي وجـدوا متغيـرات أنهـم حيث . ميك الحرارة طبقوا القانون الثاني لدينا،)١٩٩٧ (lee و linالباحثان كـذلك اخـذوا بنـضر . المثلى لكال النظامين الخطي والمتخـالف operating conditions التشغيل وظروف إيجـاد لمحيط الخارجي حيث تم إلى وسطح الزعانف base plate انتقال الحرارة من صفيحة األساس االعتبار إن الحظـوا أنهـم كما . للنظام المتخالف 1974 للنظام الخطي و 2068انت وك dreقيمة عدد رينولد المثلى *rere <d زيادة إلى باإلضافة منة في النظام المتخالف أكثر في النظام الخطي حيث انه يولد عشوائية بمعدل .بدون التأثير على معدل تولد العشوائيةslender ratio مع قلة نسبة النحافة re*قيمة عدد رينولد المثلى أخـرى بين زعنفة و الخطوة مقدار تأثيرتجريبية لمعرفة اجروا دراسة )١٩٩٣( وزمالئة jurban الباحث ts وls حذف بعض الزعـانف أوفي حالة فقدان تأثر انتقال الحرارة إلى فةباإلضا على انتقال الحرارة الكلي كـل إن أثبتت هذه الدراسة إنحيث . لكال النظامين الخطي والمتخالف missing pinsالمسمارية من المجموعة أنهـم كمـا . مثللحصول على انتقال الحرارة األ ل d5.2 تساوي إنيجب slواألفقية stالعمودية الخطوة من " مؤثرا يكون ولكن ذلك الفقدان على انتقال الحرارة اليؤثرحالة النظام الخطي في فقدان بعض الزعانف إناثبتوا وطبقها وزمالئه السابقة jurban دراسة الباحث أآملوزمالئه ) ١٩٩٥(bejanالباحث . في حالة النظام المتخالف أنبوب المثلى بين الخطوة وجدوا أنهم في جريان متقاطع، حيث tube banks اسطوانية أنابيب على مجموعة .وآخر ان ة )١٩٩٤(mandrone و azarالباحث أثير آثاف وا ت انف درس سمارية الزع دة (الم انف لوح دد الزع ع الداخل السرعة الهواء من آانت آدالة المقاومة الحرارية إن وجدوا أنهمحيث على األداء الحراري، )المساحة األداء األمثل لمجموعة زعانف مسمارية صغيره يكون إنآذلك وجدوا . التجريبية النموذج المعد للدراسة بعادوإ 5105re رينولد مخفضة ومتوسطة إعدادعند ×<. لمجوعة واألداء الحراري الضغط خسائر اجروا تجارب لدراسة )١٩٩٤(iwasakiو minakamiالباحثان إن وجدوا أنهمحيث . طي للنظام الخ وأخرىبين زعنفة مع تغير الخطوة معرضة لجريان متقاطع مارية زعانف مس إلى ، ولكن الزيادة في الخطوة العمودية يؤدي وهبوط الضغط الحرارة زيادة انتقال إلىتؤدي زيادة الخطوة األفقية .العكس رى ان أج ة palm (1996)و jonson الباحث ارب لمقارن سمارية تج انف م ة زع راري لمجموع األداء الح حسبوا األداء الحراري بمقارنة المقاومة الحرارية أنهم، حيث )دائرية، مستطيلة و قطع ناقص(مختلفة المقاطع باستخدام الزعانف المسمارية أوصوا انهم آما . لمجموعة الزعانف عند سرعة دخول للهواء وهبوط ضغط ثابتين .سرعات العالية للهواء والزعانف دائرية المقطع عند السرعات المتوسطةذات القطع الناقص في ال ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٥ , المسمارية الزعانف دراسة تجريبية على األداء الحراري لمجموعة اجروا) ١٩٩٧(وزمالئه wirtz الباحث وذج العإنحيث و الزعا fanي يتضمن مروحةمل النم دفع الهواء نح ة . نف ت واع مقطع الزعنف د آانت أن ي لق ه واستنتجوا إن الزعانف المسمارية الزعانف المسمارية إن، حيث استنتجوا diamodاالسطوانة والمربعة والماسية ومة ا ذلك آانت المق إلى باإلضافة . مروحة – حراري لمجموعة الزعانف أداء أحسن تعطي الدائريذات المقطع داخل واء ال غط اله ادة ض ع زي ل م ة تق ة الكلي درةأوالحراري ة ق اع الزعنف ة وارتف ث إن. المروح الباح zapach)حقق عمليا النموذج المستخدم إليجاد األداء الحراري األمثل لمجموعة الزعانف المسمارية ذات ) ٢٠٠٠ ع دائريالمقط ث ال ي حإن حي ية الت ات الرياض ى العالق د عل وذج اعتم ذا النم ث ه ا الباح صل عليه zukauskas)ارية ومقاومة الجريان وانتقال الحرارة من خالل دراسات على الخاصة بالمقاومات الحر)١٩٧٢ وباستخدام بعض التطوير لمعادالت . في المبادالت الحرارية المتقاطعة الجريان tube banksابيب حزمة األن وأخرى نموذج رياضي والذي يمكن استخدامه المثلية الخطوة بين زعنفة إلىتوصل الباحث , انتقال الحرارة fan curve. منحني المروحةأو سرعة المائع بثبوت ث ه kondoالباح ي )٢٠٠٠( وزمالئ به عمل ب ش دوا تقري صميم وج اد الت سمارية إليج انف م ة زع مجموع هواء يث تكون سرعة ال حimpingement cooling التصادمي ألقسري اسطوانية المقطع مبردة بطريقة الحمل قد حسبوا المقاومة الحرارية وهبوط الضغط لمجموعة الزعانف واسندوا همأنآما .فيه عمودية على قمة الزعانف . تلك العالقات الرياضيةإلثبات يةلتلك الحسابات بتجارب عم ث ا ) ٢٠٠٠(tahat الباح شغيل عملي روف الت انف وظ اد الزع أثيرات إبع ال " درس ت ى لك وة المثل ى الخط عل آما انه وجد معادالت تجريبية لمعامل . لى قيمة النتقال الحرارة النظامين الخطي و المتخالف للحصول على أع .انتقال الحرارة بالحمل لكل نظام على حده اثنين للزعانف أودراسات االمثلية السابقة آانت تعتمد على متغير تصميمي واحد إن ،الواضح من هذه المقدمة شغيل روف الت وت ظ سمارية وبثب رعة ال ( الم ضغط وس وط ال واء هب ا, ) ه ث إم ذا البح ي ه رات , ف ل المتغي آ geometric variablesضمنها متغيرات الشكل الهندسيالتصميمية ذات العالقة بالزعانف المسمارية االسطوانية انف ا الزع صنوعة منه ادة الم واص الم افةوخ ى باإلض ان إل روف الجري ي ظ اتم س ا أمثلته د أني دل تول ل مع بجع . اقل مايمكننيع التصميم والتصconstraints قيود أومحددات إلىالنسبة العشوائية ب athematical modelmالنموذج الرياضي ، يعتبر آمقياس احتكاك المائع ة وتأثيرات قترنة بانتقال الحرار المentropy generation ان تولد العشوائية لنموذج الرياضي الذي سيتم انشائه ان ا . surroundingمباشر لقدرة مجموعة الزعانف لنقل الحرارة الى المحيط ث ذا البح ي ه دل ف ين مع ة ب ضمن العالق دسيت انف تول ة الزع ة بمجموع صميم الخاص رات الت شوائية و متغي الع باسلوب سيتم ذآرة في الفقرة التالية " والتي يمكن أمثلتها رياضيا )١( آما في الشكل ذات المقطع الدائري المسمارية يسمح بأدخال جميع ظروف التشغيل للحصول على التصميم األمثل ضمن المحددات او القيود بحيث من البحث )٢٠٠٤, وزمالئهkhan(ان معدل تولد العشوائيه يمكن تمثيله بالمعادلة التاليه. المعطاة p t m r t q s a hs a ∆+⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ = ρ . . 2 ١ crمع الصفيحة األساس ضمنها مقاومة التماس وعة الزعانف لمجم هي المقاومة الحرارية الكلية hsrحيث ان ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٦ bpfinc hs rrr nka r 1 1 + + += δ ٢ حيث ان cc c ah r 1 = ، finfinfin fin ah r η 1 = ، bpbp bp ah r 1 = ، mh mh fin )tanh( =η ، kd h m fin 4 = hda fin 2 4 π = ،2 4 dnwlabp π −= ،wla = اء )٢٠٠٤( khanالباحث ـ انش م تغير الطول , ولكون التبريد عمودي في هذا البحث, finhعالقة تحليلية ل ت *)(/2الى dالمميز ldd لة مع السلوك العملي للتبريد التصادمي حسب حيث تمت مقارنة نتائج هذه المعاد =+ : آاآلتي)durbin١٩٩٢( وhollworthتجربة البحثان ⎟ ⎠ ⎞ ⎜ ⎝ ⎛= * 3/12/1 1 prre d k ch adfin ٣ :ة هو ثابت يحسب من المعادل1cحيث ان [ ] 212.0285.01 )55.0exp(25.0 ltl sssc −+= ٤ ـ ة ل ة تحليلي شاء عالق سابق ان ث ال س الباح ول bphان نف ددة الط صفيحة مح ز ,lل ول الممي م تغيرالط ث ت حي *)(/2الى wll :آاآلتيلنفس السبب المذآور اعاله =+ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛= * 3/12/1 prre75.0 l k h albp ٥ :آاآلتي آتلة الهواء خالل صفوف الزعانف ان معدل تدفق ] 4 [ 2 . dnnwlum lta π ρ −= ٦ :الحاصل نتيجة لمرور الهواء عبر صفوف الزعانف المسمارية يكون ∆pهبوط الضغط ان ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ++=∆ 22 1 2 tl lta nn fcdnnup ρ ٧ -5(حسابه من اشتقاق معادله تحقق البيانات للجدول هو معامل االعاقة للجريان العمودي والذي يمكن cd حيث ان : آاآلتيdonald, 1998)(في المصدر) 7 2)/(023.0)/(32.012.1 dldlcd +−= ٨ ث ل f إنحي و معام اك ه ائعاالحتك دها للم ي اوج ية الت ات الرياض ن العالق سب م ذي يح )٢٠٠٤ (khan وال :آاآلتي ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − + = dts kf re)1( 78.45233.0 1.11 ٩ khan والذي يحسب من العالقات الرياضية التي اوجدها تكاك المائعمل التصحيح لمعامل اح هو معا 1kحيث ان :آاآلتي) ٢٠٠٥( ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٧ 0553.0re/09.1 1 1 1 009.1 d l t s s k ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ − − = ١٠ آل المعادالت الرياضية لمعامالت األحتكاك ومعامالت التصحيح تم اشتقاقها من المنحيات المعطات في المصدر zukauskas )١٩٧٢(. : آاآلتي هولمتغيرات التصميمان اسلوب حساب القيم المثلى wq حيث cpuدقيقة آالمعالج في الحاسوب من الدوائر األلكترونية الqاختيار قيمة -١ 10≈. . والتي تعتمد على نوع المادة المصنوعة منهاkالحرارية وموصليتها δحدد سمك الصفيحة األساس -٢ . ودرجة حرارة الجوau الهواءحدد سرعة -٣ ),,,,(pr حدد خواص الهواء -٤ ap kc µρ. ),,,,,(حدد ابعاد مجموعة الزعانف -٥ lt nnhdwl. ),,,,,,,,(حدد متغيرات التصميم -٦ staggredinlinenqtwhud aa. ),,(على متغيرات التصميمود ضع المحددات او القي -٧ ≥≤=. .٢ من المعادلة hsrاحسب المقاومة الحرارية الكلية -٨ )107(حساب الضغط من المعادالت طبق معادالت -٩ −. .اتبع اسلوب األمثلية والذي سيعرض في الفقرة التالية من البحث -١٠ ),,,( المثلى خزن متغيرات التصميم -١١ **** nhud a. optimization procedureاسلوب األمثلية فعالة في حالة ألنها طريقة sumtوهي طريقة لألمثلية التحليلية سيتم استخدام احدى الطرق في هذا البحث نقطة يقة تتطلب حيث ان هذه الطر . على متغيرات التصميم inequality constraintsقيود عدم المساواة وجود ),,,,.....(بداية nxxxxx ,objective function (bunday الهدفبحيث تكون قريبة من القيمة الدنيا لدالة 321 ),(تكون دالة الهدف sumt حسب طريقة .(1985 rxψ آما يلي: )()(),( xrpxfrx +=ψ ١١ ∑حيث ان = = m i i xc xp 1 1 )( في حالة مخالفة والتي تصبح ماالنهاية penality functionمثل دالة العاقبة ، وهي ت)( nxxxxوان . للصفر xci)(وذلك بسبب مساواة القيد constraintقيأي .....,,,, تمثل متغيرات التصميم 321 ltaوالتي تمثل nnud ),(ان . في هذا البحث ,,, rxψ تمثل معدل تولد العشوائية مضاف اليها المحددات او .د يوالق ار قيمة ة rان اختي ة المثلى للتصميم،تؤثر بشكل آبير على سرعة ايجاد initial األبتدائي في هذا البحث الحال :r لـبتدائيةسنستخدم األسلوب التالي أليجاد القيمة األ )()(),( xprxfrx ∇+∇=∇ψ ١٢ :وبالتالي يكون" تربيع المتجة اعاله يكون صغير جدا 02 2 =∇∇+∇∇+∇∇ )()()()()()( xpxprxpxfrxfxf ttt ١٣ : تكونrاذن القيمة األبتدائية لـ ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٨ )()( )()( xpxp xpxf r t t ∇∇ ∇∇ −= ١٤ ة ـ initialان القيمة األولي تعطي r ل اله س ة اع دة وبسرعة حسب المعادل ائج جي ة تقليل . نت اء rان طريق اثن α/kkستكون iterationsالمحاوالت rr والذي α=10في هذا البحث تم اختيار قيمة . ثابت α، حيث ان 1+= . دقيق وبعدد محاوالت اقلئج ساعد باعطاء نتا cpuآالمعالج في الحاسوب في الدوائر األلكترونية الدقيقة في هذا البحث تم اعتماد القيود الشائعة األستخدام :المسمارية دائرية المقطع بكثره آما يليحيث تستخدم فية الزعانف )(. mmd 310 ≤≤ )/(60.1 smu a ≤≤ kmwknn wqmmkt mmhmmwmml lt ./400,10 10,2,300 12,4.25,4.25 === === === δ :باألضافة الى القيود اعاله نحصل على ١بالمعادلة ١٢ المعادلة بتعويض ( ) ⎪ ⎪ ⎪ ⎪ ⎪ ⎩ ⎪ ⎪ ⎪ ⎪ ⎪ ⎨ ⎧ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ − + − + − + − + +− + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = aa a t lada uudd r t dlsunf lkn t q lknc t q rx 6 1 1 1 3 1 1.0 1 2 )1( prre75.0prre ),( 3 max 3/12/1 2 3/12/1 1 2 ρ ππ ψ ١٥ . وتم الحصول على النتائج ادناهc++تم برمجة األسلوب اعاله باستخدام لغة results and discussionالنتائج و المناقشة ة " نتيجة ة العالي ة مجموعة الزعانف وصغر الحجملألحمال الحراري ان امثلي ذلك ف ات، ل ة التطبيق في اغلبي امثلة ان الهدف األساسي لهذا البحث . قد اصبحت في غاية األهمية لتبريد الدوائر األلكترونية الدقيقة المستخدمة .ع التبريد االفقيومقارنتة م) العمودي( لحالة التبريد التصادميومقارنة األداء الكلي يمثل معدل تولد العوائية لمجموعة زعانف مرتبة بالنظام الخطي ذات موصلية حرارية آلية وآثافة )٢(الشكل حيث ان اختيار النظام المتخالف في حالة التبريد العمودي اليعطي صورة للمقارنة لعدم وجود بين النظامين . عاليتين المالحظ . لحالة التبريد األفقي )٢٠٠٤, وزمالئه khan( هذا البحث تمت مع المصدر ان المقارنة في . في هذه الحالة mmdمعدل تولد العشوائية لحالة التبريد األفقي يكون اعلى لغاية ان , من الشكل اعاله مع " مقارنة ثم يقل , =85.1 ة د العمودي بعد هذه القيمة لقطر الزعنف ة التبري د لحال د العشوائية تستمر لكال .معدل التول اده بمعدل تول ان الزي من اصغر الى اعلى قيمة لقطر " الحالتين ولكن هذا المعدل للتولد لحالة التبريد العمودي يكون في تزايد ابتداء ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ٩ التبريد بينما , mm85.1يمكن استنتاج ان التبريد األفقي هو األفضل لمجموعة زعانف ذات قطر اآبرمن . الزعنفة smu ولسرعة هواء mm85.1العمودي سوف يكون هو األفضل لمجموعة زعانف ذات قطر اقل من a /8.1≤. شكل واء )٣(ال سرعة ه ي ل د األفق ودي والتبري د العم ة التبري شوائية لحال د الع دل تول ين مع ة ب ل المقارن يمث smu a mmdان معدل تولد العشوائية للتبريد األفقي سوف يقل لغاية , حظ من الشكل اعاله المال. =2/ ثم =78.1 يمكن . اما في التبريد العمودي ستستمر الزيادة بمعدل تولد العشوائية , تلك القبمة لقطر الزعنفة بالزيادة بعد يبدأ بينما التبريد العمودي يكون هو , mm75.1ات قطر اقل من هو األفضل لمجموعة زعانف ذ استنتاج ان التبريد األفقي smu ولسرعة هواء mm75.1األفضل لمجموعة زعانف ذات قطر اآبر من a /28.1 ≤≤. smu يمثل نفس المقارنة المذآورة اعاله ولكن لسرعة هواء )٤(الشكل a ان , لمالحظ من الشكل اعاله ا. =2.2/ سلوك معدل تولد العشوائية قد تغيربحيث انه يتساوى لحالتي التبريد األفقي والتبريد العمودي لمجموعة زعانف ذات mmdقطر , mm15.2, يمكن استنتاج ان التبريد العمودي هو األفضل لمجموعة زعانف ذات قطراقل . =15.2 smuولسرعة هواء mm15.2نما التبريد األفقي هو األفضل لمجموعة زعانف ذات قطر اآبر من بي a /2.22 ≤≤. يمثل المقارنة بين مساهمة انتقال الحرارة واحتكاك المائع للتبريد األفقي والتبريد العمودي تحت نفس )٥(الشكل المالحظ من الشكل اعاله ان مساهمة انتقال الحرارة بالتبريد العمودي . لحراريةظروف الجريان ونفس الموصلية ا تكون اآبر من نفس المساهمة للتبريد األفقي وذلك ألن التبريد العمودي يرآزعلى تبريد الصفيحة وبالتالى تقليل التبريد األفقي وذلك بسبب ان مساهمة احتكاك المائع في معدل تولد العشوائية يكون اآبر في حالة . درجة حرارتها والتي dragلألعاقة " اما في حالة التبريد العمودي تكون المساهمة نتيجة , separationظاهرة انفصال الجريان .تبديها الصفيحة األساس وراس الزعنفة conclusionsاألستنتاجات انف -١ ل للزع صميم األمث اد الت ي أليج لوب علم يح اس راء وتوض م اج سمارت ال ية الم أثيرات انتق ضمين ت ك بت وذل انتقال الحرارة وميكانيك ، حيث آانت هذه الطريقة جديدة وذلك بالدمج بين ديناميك و "الحرارة واحتكاك المائع آنيا ).العمودي(التصادمي لوصف انتقال الحرارة للتبريد d* و l*حيث تم استنتاج اطوال مميزة جديدة , الموائع ائع -٢ ول الم رعة دخ أثيرات س اد ت م ايج د ت ة التبري شوائية لحال د الع ي لتول دل الكل ى المع ة عل ر الزعنف وقط ).العمودي(التصادمي بينما التبريد العمودي سوف يكون , mm85.1 ان التبريد األفقي هو األفضل لمجموعة زعانف ذات قطر اآبرمن -٣ smu ولسرعة هواء mm85.1فضل لمجموعة زعانف ذات قطر اقل من هو األ a /8.1≤. بينما التبريد العمودي يكون هو , mm75.1 ان التبريد األفقي هو األفضل لمجموعة زعانف ذات قطر اقل من -٤ smu ولسرعة هواء mm75.1األفضل لمجموعة زعانف ذات قطر اآبر من a /28.1 ≤≤. بينما التبريد األفقي هو األفضل , mm15.2, ان التبريد العمودي هو األفضل لمجموعة زعانف ذات قطراقل -٥ smu هواء ولسرعةmm15.2لمجموعة زعانف ذات قطر اآبر من a /2.22 ≤≤. references المصادر ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٠ azar, k. and mandrone, c. d., 1994 “effect of pin fin density of the thermal performance of unshrouded pin fin heat sinks,” asme journal of electronic packaging, vol. 116, pp. 306309. bejan, a., 1995 “the optimal spacing for cylinders in crossflow forced convection,” asme journal of heat transfer, vol. 117, pp. 767-770. bejan, a. and morega, a. m., 1993 “optimal arrays of pin fins and plate fins in laminar forced convection,” asme journal of heat transfer, vol. 115, pp. 75-81. bunday, b. d., 1985,"basic optimization methods", edward arnold, u.s.a. donald, r.p.,1998,"theory and problems of heat transfer", 2nd ed., mcgraw-hill, n.y. hollworth, b.r. and durbin, m., 1992,"impingement colling of electronics," asme journal of heat transfer, vol. 114, pp.607-613. jonsson, h. and palm, b., 1996 “experimental comparison of different heat sink designs for cooling of electronics,” asme, htd-vol. 329, national heat transfer conference, vol. 7, pp. 50-55. jubran, b. a., hamdan, m. a., and abdullah, r. m., 1993 “enhanced heat transfer, missing pin, and optimization for cylindrical pin fin arrays,” asme journal of heat transfer, vol. 115, pp. 576-583. khan, w. a., 2004, “modeling of fluid flow and heat transfer for optimization of pin-fin heat sinks,” ph. d. thesis, department of mechanical engineering, university of waterloo, canada. khan, w. a., culham, j.r., and yovanovich, m.m., 2004"optimization of pin fin heat sinks using entropy generation minimaztion," inter society conference on thermal phenomena, pp. 259267. kondo, y., matsushima, h. and komatsu, t., 2000 “optimization of pin-fin heat sinks for impingement cooling of electronic packages,” j. of electronic packaging, vol. 122, september, pp. 240-246. lin, w.w. and lee, d. j., 1997 “second-law analysis on a pin fin array under crossflow,” int. j. heat mass transfer, vol. 40, no. 8, pp. 1937-1945. minakami, k. and iwasaki, h., 1994 “heattransfer characteristics of pin-fins with in-line arrangement,” heat transfer – japanese research, vol. 23, no. 3, pp. 213-228. poulikakos, a. and bejan, a.,1982 “fin geometry for minimum entropy generation in forced convection,”asme journal of heat transfer, vol. 104, pp. 616-623. tahat, m. a., kodah, z. h., jarrah, b. a. and probert, s. d., 2000 “heat transfer from pin-fin arrays experiencing forced convection,” applied energy, vol. 67, pp. 419-442. wirtz, r. a., sohal, r., and wang, h., 1997 “thermal performance of pin-fin fan-sink assemblies,” j. of electronic packaging, vol. 119, march, pp. 26-31. zapach, t., newhouse, t., taylor, j., and thomasing, p., 2000 “experimental verification of a model for the optimization of pin fin heat sinks,” the seventh inter society conferenceon thermal phenomena, las vegas, nevada, usa, may 23 26, vol. 1, pp. 63-69. zukauskas, a., “heat transfer from tubes in crossflow,” advances in heat transfer, vol. 8, pp. 93-160, 1972. ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١١ .مجموعة زعانف مسمارية دائرية المقطع مربوطة باللوحة االساس): ١(الشكل smuيد العمودي والتبريد األفقي لسرعة هواء مقارنة معدل تولد العشوائية بين التبر): ٢(الشكل a /8.1= ts ls auat l h w d q δ 5.1 6.1 7.1 8.1 9.1 1.20.2 0 00 8.0 0 00 9.0 0 0 10.0 0 0 11.0 . s )/( kw )( m md ي د افق تبري ودي د عم تبري ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٢ smuمقارنة معدل تولد العشوائية بين التبريد العمودي والتبريد األفقي لسرعة هواء ): ٣(الشكل a /2= smuمودي والتبريد األفقي لسرعة هواء مقارنة معدل تولد العشوائية بين التبريد الع): ٤(الشكل a /2.2= 5.1 6.1 7.1 8.1 9.1 1.20.2 0008.0 0009.0 0010.0 0011.0 . s )/( kw )(mmd تبريد افقي تبريد عمودي 5.1 6.1 7.1 8.1 9.1 1.20.2 0008.0 0009.0 0010.0 0011.0 . s )/( kw )(mmd تبريد افقي تبريد عمودي تبريد افقي ٢٠٠٩ ١ العدد ٢ الد جملة القادسية للعلوم اهلندسية ١٣ معدل تولد العشوائية بين التبريد العمودي والتبريد مساهمة انتقال الحرارة واالحتكاك فيمقارنة): ٥(الشكل األفقي )(mmd . s )/( kw 5.10.0 0.1 0.2 0010.0 0020.0 0030.0 تبريد افقي-انتقال حرارة تبريد عمودي انتقال حرارة تبريد افقي-احتكاك المائع بريدعمودي-احتكاك المائع al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 267 the effect of inlet pressure on steam flow behavior across a convergent-divergent nozzle prof.dr. arkan kh. al-taie dr. hussein w. mashi mohammed m. al-kafagy arkanaltaie@yahoo.com hussienmashi@yahoo.com eng.mms71@yahoo.com received 22 march 2015 accepted 18 may 2015 abstract convergent-divergent nozzle has many applications especially in steam turbine. the aim of this work is to see the effect of varying inlet pressure on steam behavior through the c-d nozzle. this was done experimentally and numerically. in the experimental part, a c-d nozzle was designed and fabricated in a test section. steam was fed from boiler at range of (0.69-0.36) bar at saturation temperature for each pressure. shadowgraph optical method was used to see the formation of shock waves and condensation zone. in the numerical part, the nozzle was simulated using fluent under ansys code 15.0. in the experimental results, it was found that the most important influence of rapid condensation on the pressure distribution is occurred downstream the through area, when the flow in the divergent part is termed supersonic the heat release causes a pressure rise in the zone of rapid condensation. shock wave appears in the divergent part due to over-expansion. each of condensation zone and shock wave were showed by using shadowgraph optical method. in the numerical approach, droplet growth rate contour are presented. the maximum droplet growth rate is (1020 micron /sec) and occurred downstream the throat area. the comparison of experimental and numerical results show good agreement. key words: c-d nozzle, steam condensation, shock wave, over-expansion, shadowgraph. متباعدة-تأثير الضغط الداخل على سلوك جريان البخار عبر فوهة متقاربة الطائي د. حسين وهيب ماشي محمد مهدي صالحأركان خلخال حسين د. أ. الخالصة تأثير نرىالفوهة المتقاربة المتباعدة توجد في الكثير من التطبيقات خصوصا في التوربينات البخارية. الهدف من هذا العمل هو ان فوهة تصميم تم ،لعمليا الجزء في. نظرياو عمليا ذلك تم وقد .متباعدة-متقاربة فوهة خالل البخار سلوك على الضغط الداخل تغيير لكل التشبع حرارة وبدرجة بار (...9-0..9) من وبمعدل المرجل من يجهز البخار. االختبار قسم في ووضعت متباعدة-متقاربة محاكاةتمت العددي، الجزء في. التكثيف ومنطقة الصدمة موجات تشكيل لرؤية (shadowgraphالتقنية البصرية ) استخدام تم. ضغط عندما ،في منطقة ما بعد الخنق الضغط توزيع على السريع التكثيف تأثيرأهم أن تبين ،العملية النتائج فيفونت انسز. باستخدام فوهةال تظهر. السريع التكثيف منطقة في الضغط ارتفاع يسبب يحدث فقدان للحرارة الصوت من أسرع المتباعد الجزء في الجريان يكون يتم mailto:arkanaltaie@yahoo.com mailto:arkanaltaie@yahoo.com mailto:hussienmashi@yahoo.com mailto:hussienmashi@yahoo.com mailto:eng.mms71@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 268 باستخدام صدمة وموجة التكثيف منطقة من كل أظهرت وقد. انخفاض الضغط في اإلفراط بسبب المتباعد الجزء في صدمة موجة 0909) هو الحد االقصى لمعدل نمو القطرة. معدل نمو القطراتتوزيع عرض يتم العددي، الجزء في. شعاعية صورة بصري أسلوب .جيد توافق تظهر والعددية العملية النتائج بين المقارنة. عند منطقة الخنق توحدث( ثانية/ ميكرون nomenclature: b the second virial coefficient (m3/kg) c the third virial coefficient (m6/kg2) e total specific internal energy (j/kg) h static enthalpy (j/kg) i nucleation rate (1/m3 s) kb boltzmann constant (=1.3807×10−23 j/k) m mass (kg) p pressure (pa) r radius of droplets (m) ̅ mean droplet radius of droplets (m) droplet critical radius (m) s super saturation ratio t temperature (k) u x-axial velocity (m/s) v y-axial velocity (m/s) greek symbols β mass fraction of the condensed phase γ the ratio of specific heat capacities γ mass generation rate (kg/m3 s) η number density for droplets (1/m3) θ non-isothermal correction factor ρ density (kg/m3) σ liquid surface tension (n/m) subscripts 0 stagnation state condition g gas (vapor) l liquid s saturated state condition superscripts ⃗⃗ ⃗ vector ̅ average of a variable 1. introduction : from the viewpoints of reducing power generation costs and saving energy resources ,improving efficiency of thermal power plants is an important issue. in steam turbines , which are the main units of the plant equipment, changes between gas-liquid phases play critical role. for example, the energy loss caused by condensation is approximately one-fourth of the total loss in lowpressure turbines of a nuclear power plant. therefore, in order to design high performance steam turbines, it is essential to take into account the influences of changes between gas-liquid phases and thermodynamic properties of two-phase fluid [1]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 269 often the expansion process and condensation phenomenon in the lp turbines can be simulated under the transonic laval nozzle. according fig.1, it has seen steam expansion from superheated to wet conditions in such nozzle. nucleation onset will be happen when the subcooled vapor reaches to wilson point and thereupon effects to the supersonic flow in the nozzles. the wilson point is defined as the point of maximal subcooling along a streamline as well as the point where dry and condensing static pressure curves first separate. the classical theory calculates the condensation and evaporation rates using the gibbs free energy and the principle of detailed balance, and the nucleation rate is then calculated assuming a steady state condition. principles of the classical nucleation theory, mid the conventional compressible navierstokes gas dynamic equations were used by a number of researchers to numerically predict multidimensional condensing flows. in addition a theory for nucleation of droplets out of its vapor is required; this is obtained through refinements to classical nucleation theory [2]. some of the theoretical research (mccallum and hunt (1997)[14]; kermani et .al (2003)[13]; white (2000)[2]), assumed one dimensional flow conditions in the analysis. later studies examined twodimensional flow in turbine cascades and nozzles. also, a number of numerical studies were directed toward modeling two phase flow behavior of nucleating steam. such research is divided into two parts: the first relies on the eulerian method in analysis (mccallum and hunt (1997)[14]), while the second depends on the eulerian-lagrangian method in analysis of flow (guha and young (1991)[7]; white and young (1993)[3]; gerber (2002)[1]; kermani and gerber (2003)[12]; halma and fort (2014)[9]). such research used euler solver for conservation equations for the mixture while nucleation and droplet growth calculations were performed in a lagrangian framework by tracking particle path lines. the experimental research including only experimental research (cinar and yilbas (1998)[6]) was compared with the existing data in the literature. another experimental research was with numerical model and the comparison between the theoretical and experimental results obtained from this research. the present study includes a numerical and an experimental investigations. in the experimental part, a suitable nozzle will be designed and fabricated. a suitable test section to incorporate the nozzle will be purpose made. a shadowgraph method will be utilized to study shock appearance. while, in the theoretical part, flow simulation will be excused using ansys fluent to study the flow and shock appearance. comparison will then be made between the experimental and theoretical results and with literature as well. 2. experimental facilities: the schematic diagram of the general arrangement and main components of the system are shown in fig. (2). steam was supplied to the test section from boiler via, throttling valve and flow regulation valve. maximum steam pressure from boiler is (10 bars) and maximum steam flow rate is (1000 kg/h) and at saturation temperature of each pressure. the steam conditions at inlet to the test section can be varying by using throttling valve and the pressure supplied to the test section at the saturation temperature. the flow leaving the test section is passing to a condenser. by varying the cooling water flow rate in vacuum pump, the test section pressure ratio and hence the back pressure can be controlled. the c-d nozzle profile selected from the experimental tests conducted in moscow p.e.i (university of technology)[8] , but with some modifications contained in the present work. the symmetric nozzle al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 270 was rectangular in cross sectional area with constant width (60 mm) built in the center of a tunnel have a dimension (100*60*1000) mm see fig.(3). the sides of the tunnel must be transparent in order to allow the passage of the laser beams through the test section and received it from the other side and then verified shadowgraph system conditions, so the side of the tunnel will be such as frame contain glass. the profile of the nozzle consists of two identical parts upper and lower. nozzle profile has been drawn using solid work program and dimensions are shown in the table (1). the length of the nozzle is (140 mm).the nozzle throat, located (88 mm) from the nozzle entrance with throat area of (27*60) mm see fig.(4). material used in manufacturing nozzle is a block of aluminum has a square cross-section area with dimensions (10 cm * 10 cm). to obtain high precision of surface nozzle profile, nozzle was manufactured using cnc machine (c-tek). surface finish of the nozzle’s inner side is highly smoothed finish. in the present work, throat area of the nozzle was modified by changing the height of it. the modified height was changed from (27 mm) to (11 mm) while the width was kept the same. the modification was done by adding iron plates between the flat surface of nozzle parts (upper and lower) and the wall of the tunnel with thickness. two plates of thickness (8 mm) were used. to assemble the test section and the nozzle, the walls have been drilled and screwed with the nozzle. to carry out the surface pressure measurements, tapping was drilled into the lower part surface; also the wall tapping were drilled along the middle passage line starting from upstream to downstream of the nozzle and the space between tapping is (8 mm). see fig.(5) the shadowgraph technique was used for observing flow field; it is particularly useful where there are large density gradients, such as in steam flow across a shock wave. the schematic diagram of equipment used in this technique is shown in fig. (6). 3. mathematical modeling: 3.1. governing conservation equations for mass, momentum and energy: in the present paper, the mathematical model describing the condensing steam consists of the continuous vapor phase at temperature t and pressure p, interspersed with a large number of spherical liquid droplets. it is assumed that the liquid is monodispersed; that is, that all droplets are of the same size at one point in the flow and the interactions between droplets are neglected. to make the simulation available and efficient, the condensing steam flow is assumed to be adiabatic and inviscid. since droplet size are sufficiently small, it is assumed that the volume of the condensed liquid droplets is negligible and the velocity slip between the droplets and gaseous-phase is zero. we have adopted the eulerian–eulerian approach for modeling the condensing steam flow. and the two-phase flow is modeled using the conservation-type two-dimensional compressible navier-stokes equations, with the transport equations for the liquid-phase mass-fraction (β) and the number of liquid droplets per unit volume (η). under the foregoing assumptions, the euler equations may be written in integral form as follows[16]: (1) where: x, y and t are the space and time coordinates respectively. u, f and g are defined as: al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 271 [ ] [ ] , [ ] and the mixture density, the internal energy and specific enthalpy are determined as follows: (2) (3) (4) (5) to model wet steam, two additional transport equations are needed [4]. the first transport equation governs the mass fraction of the condensed liquid phase (β) and the other transport equation (η) determines the number of droplets per unit volume. the two equations are combined to the model in the following expression: ⃗⃗ (6) (7) and the number of droplets per unit volume (η) is calculated as follows: (8) (9) where ρl,vd, denote the liquid density, the average droplet volume and the average droplet radius. 3.2. nucleation model and droplet growth model for nucleating particles: the most widely adopted classical nucleation theory is discussed by many authors. in the present study, the non-equilibrium flow calculation considers only homogenous nucleation in pure substance and relies on the classical nucleation theory corrected for non-isothermal effects by bakhtar et. al(2005) [5]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 272 in the model, the classical homogeneous nucleation theory describes the formation of a liquid-phase in the form of droplets from a supersaturated phase in the absence of impurities or foreign particles, and the nucleation rate is given by: (11) where qc is the condensation coefficient, kb is the boltzmann constant, mm is the mass of one molecule, σ is the liquid surface tension, and θ is a non-isothermal correction factor which is given by the following relation: [ ] (12) where hlv is the latent heat of evaporation at pressure p. based on the nucleation model just described the quantity of droplets at a location in the continuous gas phase is known, and the rate at which these droplets grow can be derived on the basis of heat transfer conditions surrounding the droplet [8]. this energy transfer relation can be written as: ̅ √ (13) the mass generation rate γ in the classical nucleation theory during the non-equilibrium condensation process is given by the sum of mass increase due to nucleation (the formation of critically sized droplets) and also due to growth/demise of these droplets. therefore, γ is written as: ̅ ̅ (14) where r* is the kelvin-helmholtz critical droplet radius. the droplet will grow as its radius is larger than r* ,otherwise the droplet will evaporate. and r* is given as follows [9]: r*= (15) where s is the super saturation ratio defined as the ratio of vapor pressure to the equilibrium saturation pressure: (16) mach number was calculated from the following equation for isentropic flow saad [10]: al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 273 √ ( ) (17) where p0 is the stagnation pressure, ps is the static pressure, γ is the steam specific heat ratio and g=9.81 m/s 2 . 3.3. equation of state: the steam equation of state used in the solver, which relates the pressure to the vapor density and the temperature, is given by [29]: (18) where b,c and are the second and the third virial coefficients given by the following empirical function. 4. results and discussion : the speed of sound in a two phase mixture is not explicit, and it values depends on the local conditions, while the pressure can be directly measured. for this reason in two phase flows it is prefer able to work in terms of static pressure ratio (ps/p0), therefore the isentropic mach number can be based on this ratio. experimentally and numerically the conditions at inlet to the test section could be varied by using throttling valve while back pressure is constant. static pressure ratio and mach number distributions for the nozzle against non-dimensional distance along the nozzle are shown in figs. 7, 8, and 9 for both experimental and numerical. figs. 7, 8, and 9 show good agreement between numerical and measured distributions for both static pressure ratio and isentropic mach number. the shadowgraph photos are used to compare the flow structure and divergent part shock wave with the theoretical velocity vector and droplets growth rate contour as shown in figs. 10, 11, and 12. it can be seen that the droplet growth rate reach to maximum downstream the throat area of the nozzle due to occurring of condensation process because high expansion rate and decreasing when inlet pressure decrease and its values are (1020,666 and 535) micron/sec. the condensation zone, the area of the propagation of dark region area inside the dotted line envelope, occurred downstream the throat area due to the reduction of inlet pressure. as a matter of fact the dominant effect of phase change in high speed condensing flows is the local departures from thermodynamic equilibrium associate with the sudden release of heat from the droplets. the internal heat transfer associated with phase change is thermodynamically an irreversible process. it is well known that the release of the latent heat by the homogenously nucleating steam flow can have a strong effect on the flow dynamics when the flow is transonic or supersonic with shock waves present. very interesting results were observed from figs (11 and 12), there is a zone of over expansion on the divergent part and the flow accelerated toward the throat area and then causes to appearance of shock wave and its locations are (123 and 112) millimeters from nozzle entrance. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 274 we can noted that when the static pressure is increased in the shock wave region, an adverse pressure gradient can cause the flow to detach from the nozzle wall surface. this increase in static pressure, which contributes to increased potential energy of the flow, thereby decreases the kinetic energy of the flow. the inner layer of the boundary which is relatively slow is significantly affected by this increasing in static pressure is large enough to bring the velocity to zero or become reversed. this is clear in shadowgraph photos. 5. conclusion: in general the comparison between experimental and numerical results for the convergent-divergent nozzle flows was found to be fairly acceptable. 1.when the inlet pressure decreases and the outlet conditions is supersonic, the heat release due to condensation process causes a pressure rise in the zone of rapid condensation , which shows up in the shadowgraph photos as a dark zone. 2.when the inlet pressure decreases and the outlet is subsonic, the zone of over expansion appears as a shock wave in the divergent section. the location of this shock wave progress towards the throat when the inlet pressure decreased. this is clear in the shadowgraph photos. 3. the droplet growth rate increased when the inlet pressure decrease. 4. the location of rapid condensation zone has occurred downstream of the throat. references: [1] a. g. gerber, “two-phase eulerian/lagrangian model for nucleating steam flow”. transactions of the asme journal of fluids engineering, vol .124, pp. 465-475, june (2002). [2] a.j. white, “numerical investigation of condensing steam flow in boundary layers”. international journal of heat and fluid flow, vol.21, pp. 727-734, (2000). [3] a. j. white and j. b. young, ”time-marching method for the prediction of two-dimensional, unsteady flow of condensing steam”. journal of propulsion and power, vol. 9, no. 4, p.579, julyaug. (1993). [4] ansys fluent 15.0 theory guide. [5] f. bakhtar, j.b. young, a.j. white and d.a. simpson,”classical nucleation theory and its application to condensing steam flow calculations”. proc. imech. vol.219, part c: j. mechanical engineering science ,(2005). [6] g. cinar and b. s.yilbas, “experimental study into droplet formation in steam flows”. kluwer academic publishers,(1998). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 275 [7] guha and j. b. young, ”time-marching prediction of unsteady condensation phenomena due to supercritical heat addition”. imeche, pp.167-177, (1991). [8] h.w. mashi and s. a. alrabii,” drop diameter prediction model for liquid phase dispersion in a supersonic nozzle with wet steam flow”. journal of engineering and development, vol. 16, no.4, dec. (2012). [9] j. halama, j. fort, “homogeneous nucleation of steam in convergent-divergent nozzle”. engineering mechanics, vol. 21, no.3, p. 145–150, (2014). [10] m. a. saad,”compressible fluid flow”. prentaice-hall, inc. englewood cliffs, new jersey,1985. [11] m.h. kayhani, s. zarenezhad, e. lakzian and s.m. hashemia, ” numerical investigation of 2d condensation steam flow by eulerian-eulerian method”. international conference on mechanical, automobile and robotics engineering, malaysia,( 2012). [12] m.j. kermani and a.g. gerber,” a general formula for the evaluation of thermodynamic and aerodynamic losses in nucleating steam flow”. international journal of jet and mass transfer, vol. 46, pp. 3265-3278, (2003). [13] m. j. kermani, a. g. gerber and j. m. stockie, “thermodynamically based moisture prediction using roe’s scheme”. 4 th conference of iranian aero space society, (2003). [14] m. mccallum and r. hunt, “numerical solution of the flow of wet steam in a steam turbine using an eulerian code”. 17th dudee numerical analysis conference, june 24-27, (1997). [15] s. senoo and y. shikanow,”two-dimensional analysis for non-equilibrium homogeneously condensing flows through steam turbine cascade”. jsme international journal, series b, vol.45, no.4, (2002). [16] yong yang and shengqiang shen, “numerical simulation on non-equilibrium spontaneous condensation in supersonic steam flow”. international communications in heat and mass transfer 36 (2009) 902–907. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 276 table (1): dimensions of the selected nozzle.[8] width(b) (mm) height (h) (mm) length(l) (mm) 60 100 140 0.628 0.59 0.71 figure (1): pressure distribution along a convergent-divergent nozzle with spontaneous condensation.[11] al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 277 figure (2): the system schematics diagram figure (3): the tunnel dimensions from research conducted in moscow p.e.i.[8] al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 278 figure (4): c-d nozzle schematics diagram from research conducted in moscow p.e.i.[8] . all dimensions in millimeters. figure(5): spacing between pressure taps of modified nozzle. figure(6): shadowgraph schematics diagram al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 279 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.2 0.4 0.6 0.8 1 m a ch n o p x /p o dimensionless distance (x/l) px/po numerical px/po experimental mach no. numerical mach no. experimental 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.2 0.4 0.6 0.8 1 m a ch n o . p x /p o dimensionless distance (x/l) px/po numerical px/po experimental mach no. numerical mach no. experimental figure (7): the experimental and numerical pressure ratio and mach no. distribution at (p0 =0.69 bar , t0=..0 k , ɛ0=0.29 and pb=0.2 bar) figure (8): the experimental and numerical pressure ratio and mach no. distribution at (p0 =0.45 bar , t0=.50 k , ɛ0=0.44 and pb=0.2 bar) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 280 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.2 0.4 0.6 0.8 1 m a ch n o . p x /p o dimensionless distance (x/l) px/po numerical px/po experimental mach no. numerical mach no. experimental figure (9): the experimental and numerical pressure ratio and mach no. distribution at (p0 =0.36 bar , t0=.4. k , ɛ0=0.55 and pb=0.2 bar) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 281 rapid condensation zone figure (10): (po =0.69 bar , to=362 k ,pb=0.2 bar). (a) shadowgraph photo. (b) the predicted droplet growth rate contour t h ro a t 𝑑𝑟 𝑑𝑡 (micron/s) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 282 t h ro a t figure (11): (po =0.45 bar , to=352 k ,pb=0.2 bar). (a) and (b) shadowgraph photos for the throat and divergent part respectively. (c) the predicted droplet growth rate contour heat release zone and rapid condensation zone appearance of shock wave in divergent part 𝑑𝑟 𝑑𝑡 (micron/s) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 283 progress of the shock wave separation flow after shock wave rapid condensation zone figure (12): (po =0.36 bar , to=346 k ,pb=0.2 bar). (a) shadowgraph photo. (b) the predicted droplet growth rate contour 𝑑𝑟 𝑑𝑡 (micron/s) article al-qadisiyah journal for engineering sciences 12 (2019) 127–134 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7803280891. e-mail address: ali.abbar@qu.edu.iq ( ali h.abbar) https://doi.org/10.30772/qjes.v12i1.601 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. electrochemical removal of copper from simulated wastewater using a rotating tubular packed bed of woven screens electrode jenan h. hemeidan a and ali h. abbar a* a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 30 june 2019 received in revised form 19 july 2019 accepted 19 july 2019 keywords: three-dimensional electrodes rotating cylinder electrode woven screens copper removal response surface methodology a b s t r a c t copper removal from simulated wastewater was investigated by using a rotating tubular packed bed of woven screens electrode as a cathode in a new design of the electrochemical reactor. the effects of electrolysis operating parameters like current (0.5–2.5 a), rotation speed (150–750 rpm), and initial copper concentration (100–500ppm) were investigated. optimization of process parameters was carried out by adopting response surface methodology (rsm) combined with box–behnken design (bbd), where copper removal efficiency was selected as a response function. the results indicated that the current has the main effect on the copper removal efficiency followed by rotation speed and concentration. the results of regression analysis revealed that the experimental data could be fitted to a second-order polynomial model with a value of determination coefficient (r2) equal to 0.9894 and fisher test at a value of 51.57. the optimum conditions of the process parameters based on rsm method were an initial copper concentration of 205 ppm, current of 2.5a, and rotation speed of 750 rpm utilizing cathode composed of screens with mesh no. 30 where a final copper concentration less than 2 ppm was obtained after 30 min. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction copper considers an important element necessary for humans and other living organisms, which included numerous enzymes and proteins. copper is used in the manufacturing of electrical wiring, fittings, valves, pipes, cooking utensils, coins, and building materials. on other hand copper compounds are utilized in insecticides, algaecides, fungicides, wood preservatives, azo dye synthesis, electroplating industry, engraving, lithography, pyrotechnics, and petroleum refining plants. however, copper is recognized as one of heavy metals that generates serious environmental hazards, wastewaters from metal finishing, weaving, and electronics industries may contain copper with concentration up to 500 mg/l. based on the worldwide environmental regulations, this level of concentration is higher than the permitted level and treatment of these wastewaters must be achieved before being discharged into the environment [1]. the allowable limit of copper in sources of drinking water like rivers is in the range of 1.5 to 2 mg/l based on the european union restrictions, so it is preferred to discharge the effluents within this limit [2]. removal of copper from waste streams has been achieved by several methods comprising adsorption, chemical precipitation, ion-exchange, biosorption, electrodialysis, reverse osmosis, membrane separation based on ionexchange, and electrochemical deposition [3]. some of these methods are verified to be efficient in copper removal, however they have no ability to recover the valuable heavy metals that can the again. for example, a large amount of precipitated sludge is generated in the chemical precipitation technique which needs further treatment. ion exchange and reverse osmosis techniques have limited applications because of the requirements of high material and operational costs. electrochemical approach as a dramatic alternative to the well-known techniques offers electrochemical reactors that used electrochemical reduction reactions as a principal approach for removal of heavy metals ions from wastewater, where these metals are electrodeposited at the electrode surface as solid metallic deposits when the http://qu.edu.iq/ https://doi.org/10.30772/qjes.v00i0 128 jenan h. hemeidan and ali h. abbar/al-qadisiyah journal for engineering sciences 12 (2019) 127–134 effluents flow through the electrochemical reactor hence the possibility of reusing them from the main process. herein, adding chemicals is not required leading to facilitate of water reuse [4-6]. the electrochemical method is considered as a clean, environmentally engaging technology since the major reaction reagent is the electron. economically, electrochemical method is valuable due to the lower energy consumption in comparing with the well-known techniques [5]. besides, applying the automatization in controlling current during the electrodeposition process results in lowering the workload requirements [7]. removal of copper from solutions have been attempted by several researchers using various cell designs including parallel plate electrochemical reactors [8-10], and packed bed electrochemical reactors [11-17] where some degrees of achievements and improvements have been achieved. in these works, two-dimensional electrode cells were found to be suffered extreme performance constraint, which was observed clearly as concentration limits of the effluents be stiffer. porous, packed bed electrodes offer higher specific surface area which permits achieving higher removal rates of metal ion even at more dilute effluents [18]. to ensure efficient applying of the electrochemical method for diluted effluent treatment, the electrochemical reactors should have as possible as the higher value of the product of mass-transfer coefficient and specific surface area of the cathode which in turn improve the space time yield of the reactor. this aim can be accomplished by using packed bed rotating cylinder electrodes which have been recognized as an efficient type of electrochemical reactor that used for heavy metals removal [19]. this kind of electrochemical reactor has features not engaged by other reactors, for instance, the possibility of operating at continuous mode and a simple operable compact design [20, 19]. it can be run at concentration limit from 1 ppm to 1000 ppm, where the higher value resembles the concentration of most heavy metals in different industrial effluents while lower value matches the legislation constraints [21]. heavy metals removal was carried out formerly by using rotating cylinder electrodes with a packed bed in the form of woven wire meshes and reticulated vitreous carbon (rvc) [22, 13, 23]. previous studies showed that the packed bed rotating cylinder electrode of woven wire meshes when compared with the other types of packed bed rotating cylinder electrodes, has a value of mass transport coefficient greater approximately by three times than those observed in smooth rotating electrode as a result of higher turbulencepromoting action of the meshes [24], however, the electrode thickness should be kept small for assuring the whole bed to be work under limiting current conditions [25]. tubular packed bed of woven screens cylinder electrode is one of packed bed rotating cylinder electrodes that not be used before as a packed bed rotating cylinder electrode for heavy metals removal [26]. in this configuration, the cathode was constructed from a number of coaxial closely packed layers of vertical screen cylinders. this type of rotating cylinder electrode has high turbulence-promoting action due to its high surface area per unit volume. abdel-aziz [26] studied the mass transfer in this type and found that this type has a value of volumetric mass transfer coefficient greater than that obtained at smooth rotating cylinder. therefore, the major purpose of the present research is to examine the performance of a modified design of this type of rotating cylinder electrode for copper removal. the modified tubular packed bed rotating electrode is composed of a stainless steel perforated hollow cylinder which used as a current feeder where continuous layers of stainless steel screens are winded around it and bounded by two sleeves. this new configuration help in using high rotation speed hence higher turbulence action can be achieved. besides, this configuration could be easily scaled–up to the industrial scale. the stated novelty of the present work is based on the using of tubular packed bed woven screen rotating cylinder electrode as a packed bed rotating electrode for copper removal. in previous studies, the removal of heavy metals by electrochemical deposition method was studied utilizing a well-known one-factor-at-a-time method (ofat). this method changes only one variable at a time whereas keeping others fixed. however, the interactions of the variables couldn’t be specified from ofat runs. the designed experiment method is a more effective method than ofat method for evaluating the effect of two or more variables on the response of the process under study as well as their interactions. lower resources (experiments, time, and materials) are needed by adopting the designed experiment technique to get the desired information. besides, the evaluation of the effects of each variable is more accurate by adopting the designed experiment technique [27]. response surface methodology (rsm) is a vital subject in the statistical design of experiments. it was used efficiently in different processes for wastewater treatment such as adsorption [28], disinfection of chlorine [29], electrocoagulation [30], fenton-related process [31], electrochemical oxidation [32], and heavy metals removal [22]. response surface methodology used a group of statistical and mathematical techniques for modeling and analyzing many problems in which various variables affected the response of the process. the object of rsm is to assessment the relative effect of various affecting variables and finally obtaining the optimum conditions by upgrading this response [33]. hence, the second aim of this research is to optimize the variables of copper removal process like initial metal concentration, current, and rotation speed for improving copper removal efficiency from simulated wastewater using a tubular packed bed woven screens electrode. as a method of optimization, box-behnken design (bbd) of the response surface methodology was applied in this study. we believe that this is the first work that uses an optimization approach by bbd for electrochemical removal of copper utilizing a tubular packed bed woven screens electrode where no previous works have been reported in this field. 2. experimental work 2.1. materials and system the electrolysis runs were performed in a 0. 5 l perspex electrolytic cell. the cathode (working electrode) was a rotating tubular packed bed electrode composed of 316 stainless steel woven screens wrapped around stainless hollow cylinder acting as a current feeder. the hollow cylinder current feeder was opened at the bottom and closed at the upper. it is perforated with a total of (15) holes with a diameter (6mm) distributed uniformly on the lateral surface of the cylinder. the cathode feeder has an outer diameter (35 mm), inner diameter (28mm) with total length (60 mm). the lower part of this feeder is jointed with a teflon sleeve has diameter (50mm) and height (12 mm), while the upper part is jointed with a teflon sleeve has diameter (50mm) and height (17 mm) in order to fix the wrapped woven screens sheets on the current feeder. the cathode current feeder was attached to the shaft of variable speed motor via a stainless steel rod (7 mm diameter and 100 mm length) fixed on the cathode feeder. the cathode has an apparent surface area of (117.81 cm2) (50 mm diameter and 60 mm long). outer graphite cylinder having dimensions (90 mm inside diameter, jenan h. hemeidan and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 127–134 129 5 mm thickness, and 90 mm long) and central graphite rod having dimensions (60 mm length and 20 mm diameter) were used as anode (counter electrode). for ensuring a uniform primary current distribution, the three electrodes (cathode, outer anode, and inside anode) were concentric in the cell body. figure 1 displays the schematic diagram of the experimental setup. figure 1: schematic diagram of the experimental setup:1) cell body, 2) cathode, 3) outside anode, 4) inside anode, 5) jacket, 6) power supply, 7) ammeter, 8) electrical motor,9) voltmeter,10) water bath circulator before starting any run, the cathode was washed with (1m) nitric acid solution in an ultrasound cleaner for removing copper deposits of the previous run then rinsed again thoroughly by double-distilled water. the galvanostatic copper deposition was conducted by using power supplymodel tp-1305ec, 30v / 5a. stainless steel screens having mesh numbers 30 and 60 were used. the properties of these screens are presented in table 1. screen porosity (ε) was evaluated by determining the screen weight /area density and applying eq. 1, then screen specific surface area(s) was computed based on eq.2 [34]: 𝜀 = 1 − 𝑚𝑠 𝜌𝑠𝑙𝑎𝑠 (1) 𝑠 = (1 − 𝜀)𝑟 (2) where (r) is the surface to volume ratio of the screen wire equal to (4/d), (ms /as) is the weight /area density, (ρs) is the density of stainless steel 316aisi equal to 8.027gm/cm3 [35], (l) is the screen thickness equal to 2d. the woven type of the screen was identified by using olympus bx51m with dp70 digital camera system whereas a digital caliper was used to measure wire diameter (d). table 1. screen properties mesh number (wire/inch) 30 60 type of woven plain square full twill d, cm 0.030 0.020 (ms/as), g/cm 2 0.1237 0.1291 𝜀 0.7146 0.6345 𝑠, cm-1 38.06 73.1 copper sulfate (cuso4) is used as a source of copper ion while sodium sulfate (na2so4) was used as a supporting electrolyte. all chemicals were of reagent grade. doubly distilled water was used for preparing electrolytic solutions containing copper ions dissolved in 0.5m na2so4 at concentrations (100, 200, 300, 400, and 500 ppm). the final ph of electrolytic solutions was 2 adjusted by using (1m) h2so4 or (1m) naoh. all runs proceeded at a fixed temperature of 30±1°c. the removal efficiency (re, %) was computed according to the following equation [36] : 𝑅𝐸 = 𝐶𝑖−𝐶𝑓 𝐶𝑖 × 100 (3) where ci is the initial copper concentration, cf is the final copper concentration after an interval of time (∆t). current efficiency (ce, %) is the ratio of the actual mass of copper ion electrodeposited on the cathode surface to the theoretical mass that could be electrodeposited according to faraday's law, it can be determined according to the following equation [36] : 𝐶𝐸 = 100𝑧𝑖∙𝐹∆𝑚 𝑀𝑖 𝐼 ∆𝑡 (4) where f is the faraday constant (96487a s mol-1); ∆m is the mass of copper electrodeposited at period of time ∆t (g); mi is the molar mass of copper (63.546 g/mol), zi is the number of electrons, i is the applied current (a) and ∆t is the electrolysis time (s). the specific energy required for operating the electrochemical reactor is the major item in evaluating the cost of any electrochemical process. it is defined as the energy required for producing or treating a certain amount of the substance on a molar, mass, or volume basis. specific energy consumption (ec, kwh kg-1) can be evaluated according to the following equation [36]: 𝐸𝐶 = 2.788×10−4𝐸𝐼∆𝑡 ∆𝑚 (5) where e is the voltage of cell (volt). 2.2. design of experiments the relationship between a process response and its variables can be determined by applying a collection of mathematical and statistical techniques adopted by rsm [37]. in this study, the 3-level 3-factor box– behnken experimental design is implemented to verification and check the variables that influenced the removal of copper from simulated wastewater. current (x1), rotation speed (x2), and initial copper ion concentration (x3) were taken as process variables, while the efficiency of copper removal was taken as a response. the scales of process variables were coded as -1 (low level), 0 (middle or central point) and 1 (high level) [38]. table 2 illustrates the process variables with their chosen levels. box–behnken improves designs to get the suitable quadratic model with the required statistical properties by using only a part of the runs needed for a 3-level factorial. the number of runs (n) needed for performing of box–behnken design can be determined by the following equation [39]: n =2k (k-1) + cp (6) 130 jenan h. hemeidan and ali h. abbar/al-qadisiyah journal for engineering sciences 12 (2019) 127–134 where k is the number of process variables and cp is the reiterated number of the central point. table 2, process variables with their level for copper removal process variables levels in box–behnken design coded levels low(-1) middle(0) high (+1) x1-appliedcurrent(a) 0.5 1.5 2.5 x2-rotation speed(rpm) 150 450 750 x3-cu(ii) concentration(ppm) 100 300 500 in this research, fifteen runs were conducted for evaluating the effects of the process variables on the copper removal efficiency. table 3 illustrates the bbd proposed for the present research. table 3, boxbehnken experimental design run blk coded value real value x1 x2 x3 current (a) rotation speed (rpm) concentration (ppm) 1 1 -1 0 1 2.5 450 100 2 1 -1 -1 0 1.5 150 100 3 1 -1 0 -1 0.5 450 100 4 1 0 0 0 1.5 450 300 5 1 0 -1 1 2.5 150 300 6 1 1 -1 0 1.5 150 500 7 1 1 0 -1 0.5 450 500 8 1 0 0 0 1.5 450 300 9 1 0 0 0 1.5 450 300 a second order polynomial model can be adopted based on bbd were fitting the interaction terms with the experimental data can be described by the following equation [40]: 𝑌 = 𝑎0 + ∑ 𝑎𝑖 𝑥𝑖 + ∑ 𝑎𝑖𝑖 𝑥𝑖 2 + ∑ 𝑎𝑖𝑗 𝑥𝑖 𝑥𝑗 (7) where y represents the dependent variable (re), i and j are the index numbers for patterns, 𝑎0 is the intercept term, 𝑥1, 𝑥2 … 𝑥𝑘 are the process variables (independent variables) in coded form. 𝑎𝑖 is the first-order(linear) main effect, 𝑎𝑖𝑖 second-order main effect and 𝑎𝑖𝑗 is the interaction effect. analysis of variance was performed then the regression coefficient (r2) was estimated to confirm the goodness of model fit. 3. results and discussion 3.1. statistical analysis the optimization of process variables and identification of the interaction among them were performed by conducting fifteen runs at different combinations of the process variables. table 4 shows the values of the removal efficiency for each run. current efficiency and specific energy consumption are also inserted in this table. it is interesting to observe that copper removal efficiency was changed from 92.27 to 99.87%, current efficiency altered from 2.6912 to 62.625%, while the energy consumption was in the range of 3.115-137.349 kwh/kg when adopting the experimental design. table 4, experimental results of box–behnken design for copper removal run blocks real value re% e volt ce % ec kwh/kg conc. (ppm) rotation (rpm) current (a) actual predict 1 1 100 450 2.5 99.70 99.88 4.37 2.69 137.35 2 1 100 150 1.5 96.80 96.89 3.59 4.36 69.77 3 1 100 450 0.5 96.10 96.23 2.70 12.97 17.60 4 1 300 450 1.5 97.10 97.13 3.53 13.11 22.81 5 1 300 150 2.5 97.60 97.33 4.09 7.90 43.82 6 1 500 150 1.5 92.27 92.66 3.25 20.76 13.26 7 1 500 450 0.5 92.80 92.62 2.31 62.63 3.12 8 1 300 450 1.5 97.10 97.13 3.53 13.11 22.81 9 1 300 450 1.5 97.10 97.13 3.53 13.11 22.81 10 1 300 750 2.5 99.87 100.1 4.74 8.09 49.55 11 1 100 750 1.5 99.25 98.86 3.65 4.47 69.08 12 1 500 750 1.5 97.70 97.61 3.46 21.98 13.33 13 1 300 150 0.5 92.32 92.11 2.60 37.38 5.89 14 1 300 750 0.5 96.00 96.27 2.35 38.87 5.11 15 1 500 450 2.5 98.14 98.01 3.64 13.25 23.24 jenan h. hemeidan and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 127–134 131 table 5, analysis of variance for copper removal source df seq ss cr. (%) adj ss adj ms f-value p-value model 9 84.2003 98.94 84.200 9.3556 51.75 0.0 linear 3 79.7751 93.74 79.775 26.5917 147.10 0.0 x1-current(a) 1 40.9060 48.07 40.906 40.9060 226.29 0.0 x2-rotation speed (rpm) 1 23.9086 28.09 23.908 23.9086 132.26 0.0 x3-concentration (ppm) 1 14.9604 17.58 14.960 14.9604 82.76 0.000 square 3 0.9512 1.12 0.9512 0.3171 1.75 0.272 x1*x1 1 0.2362 0.28 0.2362 0.2362 1.31 0.305 x2*x2 1 0.6350 0.75 0.6920 0.6920 3.83 0.108 x3*x3 1 0.0800 0.09 0.1410 0.1410 0.78 0.418 2-way interaction 3 3.4740 4.08 3.4740 1.1580 6.41 0.036 x2*x3 1 2.2201 2.61 2.2201 2.2201 12.28 0.017 x1*x3 1 0.7569 0.89 0.7569 0.7569 4.19 0.096 x1*x2 1 0.4970 0.58 0.4970 0.4970 2.75 0.158 error 5 0.9038 1.06 0.9038 0.1808 lack-of-fit 3 0.6572 0.77 0.6572 0.2191 1.78 0.380 pure error 2 0.2467 0.29 0.2467 0.1233 total 14 85.1041 100 model summary s r-sq r-sq(adj.) press r-sq(pred.) 0.425 98.94% 97.03% 11.069 86.99% minitab-17 software was used to analyze results of copper removal efficiency where an experimental relationship between copper removal efficiency and process variables was obtained and formulated by the following quadratic model of copper removal efficiency (re) in term of coded units of process variables: re% = 93.08+ 2.896 x1 + 0.00813 x2 0.01276 x3 0.000005 x320.000005 x220.253 x12+ 0.000012 x3*x2+ 0.00217 x3 *x10.001175 x2*x1 (8) eq.(8) shows how the removal efficiency is affected by the individual variables (linear and quadratic) or double interactions. the values of positive coefficients revealed that the removal efficiency increased with the increasing of the related factors of these coefficients within the tested range while values of negative coefficients revealed the opposite effect. as can be seen, concentration has a negative effect on the removal efficiency, while current and rotation speed were found to have a positive effect. the results showed that effects of interactions are not significant. the predicted values of the removal efficiency estimated from eq.8 are also inserted in table 4. the box-behnken design adequacy was identified by using an analysis of variance (anova). to test hypotheses on the parameters of the model, anova divides the total variation in a set of data into individual parts supplemented with specific sources of variation [41]. the adequacy of the model in anova analysis is recognized based on fisher f-test and p-test. most of the variation in the response can be illustrated by the regression equation if the value of fisher becomes higher. p-value is used for evaluating whether f is large enough to signalize statistical significance. 95% of the variability of the model could be clarified when a p-value lower than 0.05 [42]. table 5 illustrates anova for the response surface model. in this table, degree of freedom (df), the sum of the square (seqss), percentage contribution (cr. %) for each parameter , adjusted sum of the square (adj ss), adjusted mean of the square (adj ms), f-value, and pvalue were evaluated. f-value of 51.57 and p-value of 0.0001were obtained which elucidating high significance for the regression model. the multiple correlation coefficient of the model was 98.94% conforming to the regression is statistically significant and only 1.06 % of the total variations are not confirmed by the model. the adjusted multiple correlation coefficient (adj. r2 = 97.03%) and the predicted multiple correlation coefficient (pred. r2 = 86.99%) were compatible with this model. results of anova showed that percent of the contribution of the current is 48.07% which means that the current has the main effect on copper removal efficiency. rotation speed and initial copper concentration have miner effects. the linear term has the main percent of contribution in the model with 93.74% followed by the interaction between the input variables with a contribution of 4.08%while the square has a small contribution (1.12%) which could be ignored. the results assure that current is the most significant factor. 3.2. effect of process variables on the copper removal efficiency figures (2-a, 2-b) show the effect of the initial copper concentration on copper removal efficiency for various values of rotation speeds (150, 300, 450, 600, and 750 rpm) at constant current (1.5 a) with mesh no. of 30. figure 2-a represents the response surface plot while figure2-b shows the corresponding contour plot. from the surface plot, it was observed that, at a rotation speed of 150 rpm, a decrease in removal efficiency occurs as the initial copper concentration increased. however, a slight change in the removal efficiency happened as the rotation speed approach to 750 rpm. at the concentration of 500ppm, the results show an increase in copper removal efficiency with increasing rotation speed. however, at concentration of 100ppm, a slightly change in the removal efficiency was occurred with increasing rotation speed. the corresponding contour plot confirms that a maximum value of copper removal efficiency lies in a small 132 jenan h. hemeidan and ali h. abbar/al-qadisiyah journal for engineering sciences 12 (2019) 127–134 area in which the rotation speed ranged between 500-750rpm and copper ion concentration between 100-200ppm. the effect of the current on copper removal efficiency for different initial copper concentrations (100, 200, 300, 400, and 500 ppm) at constant rotation speed of 450 rpm with mesh no. of 30 is shown in figures (3-a, 3-b). the response surface plot (3-a) shows that currently has an important effect on copper removal efficiency where it increases quickly as the current raised up to 2.5 a. while removal efficiency slightly decreased with increasing concentration. the corresponding contour plot(3-b) confirms that a maximum value of copper removal efficiency lies in a small area in which the current ranged between 2-2.5 a and copper ion concentration between 100-200ppm. (a) (b) figure 2: response surface plot (a) and contour plot (b) showing the effect of rotation and initial concentration of copper on the copper removal efficiency (a) (b) figure 3: response surface plot (a) and contour plot (b) showing the effect of the current and initial concentration of copper on the copper removal efficiency 3.3. the optimization and confirmation test numerical optimization of the software is applied to get the precise point that maximized the desirability function (df). the desired goal was chosen by adjusting the weight or importance that could change the characteristics of the aim. five options for the aim fields for response were selected: maximum, minimum, target, within range, and none. in the present work, the aim is to get higher removal efficiency of copper so the ‘maximum’ field with corresponding ‘weight’1.0 was chosen. 92.27% was taken as the lowest limit for the removal efficiency while 99.87% was taken as the upper limit. under these settings and boundaries, the optimization procedure was conducted and the results are displayed in table 6 with the desirability function of (1). results of optimization recommended using the current of 2.5a, a rotation speed of 750 rpm, and an initial copper concentration of 205.05 to get higher removal efficiency of 100.3%. two experiments at the optimum values of the process parameters were performed to confirm the results of optimization. 205 ppm was taken as nearly the value of the initial copper concentration resulted from optimization. the results are displayed in table 7. after 30 min of the current (a) 1.5 hold values 100 052 004 29 49 69 1100 052 200 055 006 040 200 008 0 98 %er )mpr(noitator )mpp(.cnoc urface plot of res vs r% tation(rpm); conc.(ppm)o current (a) 1.5 hold values conc.(ppm) ro ta ti o n (r p m ) 500400300200100 700 600 500 400 300 200 > – – – – – < 93 93 94 94 95 95 96 96 97 97 98 98 re% contour plot of re% vs rotation(rpm); conc.(ppm) rotation(rpm) 450 hold values 52 0 004 49 96 98 1 010 52 00 0.6 055 2 1.8 1.2 0.6 22.4 98 010 %er )a( tnerruc )mpp(.cnoc urface plot of re% vs )urrent (a); conc.(ppms c rotation(rpm) 450 hold values conc.(ppm) c u rr e n t (a ) 500400300200100 2.5 2.0 1.5 1.0 0.5 > – – – – – – < 93 93 94 94 95 95 96 96 97 97 98 98 99 99 re% contour plot of re% vs current (a); conc.(ppm) jenan h. hemeidan and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 127–134 133 electrolysis, the removal efficiency of 99.127% was achieved which is incompatible with the range of the optimum value getting from optimization analysis with desirability function of (1) (table 6). therefore adopting box–behnken design combined with desirability function is successful and efficient in optimizing copper removal using a tubular packed bed of woven screens rotating electrode.reade et al. [23] investigated the potentiostatic removal of copper from acid sulfate solutions using reticulated vitreous carbon (rvc) rotating cylinder electrode. they found that an initial copper concentration of 63.5ppm could be reduced to <0.1ppm in approximately 60 min using a 100 ppi rvc at electrode potential of −500mv vs sce. the present work gives the same removal efficiency starting from an initial copper concentration of 205 ppm at half interval time under galvanostatic operation mode (constant current) which is an indication of the good performance of the present modified rotating cylinder electrode, moreover, the galvanostatic operation mode is the preferred mode at the industrial scale. other previous works that used rotating packed bed cylinder electrode were operated at single-pass flow mode of operation not batch mode [13]. table 7 shows that current efficiency was 5.2% which means that most of the current is consumed for hydrogen evolution as a side reaction. this lower current efficiency is expected since the concentration of copper very low (205 ppm) and ph of the solution is 2. previous works stated that hydrogen ions discharge as a side reaction is strongly competitive to the electrodeposition of copper ions on the surface of cathode as the acidity of the solution is increased [43]. of course operating at ph higher than 2 will offer superior removal of copper by electrodeposition at higher current efficiency. this can be achieved with generous caution since copper could be precipitated as hydroxide if the solution ph is greater than the value of ph for precipitation as approved by theoretical solubility of copper hydroxide diagram[44].therefore most of previous works operated at ph=2 [23, 13]. although the literature reports some values of current efficiency higher than we found at galvanostatic mode of operation, the present rotating cylinder electrode used in this study has shown very satisfactory performance in removal of copper. in addition the hydrogen evolution can be utilized as a chemical source for other industrial applications when a divided cell configuration is adopted at the industrial scale, hence another benefit from the present research can be obtained. 3.4. effect of mesh number to investigate the effect of mesh no. on the removal efficiency, two runs were performed at the optimum conditions using two mesh no. 30 and 60. the concentration profile with time for different mesh no. is shown in fig 4. it is clear there is an insignificant effect of two mesh numbers on the removal efficiency where the same concentration profiles were observed. this behavior is in good agreement with our previous research [22] in which cadmium removal by using a spiral-wound woven wire mesh packed bed rotating cylinder electrode was studied where cadmium removal efficiency was found to be not significantly changed with increasing of mesh number. figure 4, concentration versus time for two sizes of mesh no table 6. the optimum values of process parameters for maximizing copper removal efficiency response goal lower target upper weight importance re (%) maximum 92.27 99.87 100 1 1 solution:parameters results x1 (a) x2 (rpm) x3 (ppm) re (%) fit df se fit 95% ci 95% pi 2.5 750 205.05 100.13 1.0 0.39 (99.123;101.137) (98.644;101.62) table 7. confirmation of the optimum conditions for copper removal efficiency run run x1 (a) x2 (rpm) x3 (ppm) e (volt) r e(%) at 30 min ce (%) ec (kwhkg-1) re(%) at 40 min actual average 1 1 2.5 750 205 2.7 99.25 4. 99.12 5.2 77 5. 100 2 2 2.5 750 205 2.8 99 4. conclusions it was established that copper removal from a simulated wastewater solution could be performed successfully in a rotating tubular packed bed of woven screens electrode as a cathode in a batch electrochemical reactor. rms methodology is applied effectively for optimizing the process parameters and finding out the optimum levels of these parameters for copper removal which maximized the removal efficiency. based on rsm 134 jenan h. hemeidan and ali h. abbar/al-qadisiyah journal for engineering sciences 12 (2019) 127–134 analysis, it can be concluded that currently has the largest effect on the efficiency of electrochemical copper removal in comparison with the other parameters. the optimal values obtained from the optimization were cu (ii) initial concentration of 205 ppm, current of 2.5a, and rotation speed of 750 rpm. under these conditions, it could be possible to reduce cu (ii) concentration from 205 ppm to less than 2 ppm (re=99.12%) at electrolysis time of 30 min and a complete removal was obtained at 40 min. therefore, an additional benefit of the present system was gained represented by achieving complete removal and recovery of copper. 5. acknowledgments the authors wish to acknowledge the helpful and technical assistance given by the staff of the chemical engineering department, college of engineeringuniversity of al-qadisiyah. references [1] k. dermentzis, a. davidis, d. papadopoulou, a. 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[44] d. m. ayres, a. p. davis, g. m. paul, “removing heavy metals from wastewater,” university of maryland, engineering research center report, (p. 6), 1994 . al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 99 experimental investigation and nonlinear analysis of hybrid reinforced concrete deep beams prof. dr. ammar yaser ali mrs. maha ghazi zghair babylon university, engineering college, civil department received 16 march 2015 accepted 7 may 2015 abstract this study presents experimental and theoretical investigation of the overall shear behavior of reinforced concrete deep beams made from hybrid concrete strength : normal strength concrete (nsc) in tension zone and high strength concrete (hsc) in compression zone. the experimental work included testing of nine models of hybrid reinforced concrete deep beams under the effect of two point loads. one of the beams was tested as pilot and the other eight beams were divided into two groups namely group (a) and group (b) to study the effects of the following parameters: (hsc) the layer thickness, the effect of presence of web reinforcement and method of casting (i.e. monolithically or at different times), on the ultimate shear strength, the cracking load, the cracking pattern, the deflection, the ductility and failure modes. the experimental test results obtained from the adopted hybridization technique of (hsc) and (nsc) have shown that for beams made from (hsc) (about 45mpa) with a layer in compression zone of thickness (25 50)% of total beam depth, the ultimate shear strength was increased about (11.2 19.5)% for beams without web reinforcement and (16.75 22.25)% for beams with minimum web reinforcement. it has also shown that, the first cracking load was increased about (32.8 48)% and (43.4 57.9)% for beams without and with web reinforcement, respectively. the hybrid concrete beams that cast monolithically, have exhibited an increase in ductility about (13.322.6) % and (17.3 26.3) % for specimens without and with web reinforcement, respectively. while, the hybrid concrete beams with construction joint and epoxy resin layer of thickness about (1mm), have exhibited larger increasing in ductility about (28.7%) and (30.2%) for specimens without and with web reinforcement, respectively. on the other hand, a non-linear three dimensional finite elements simulation using ansys computer program was adopted to trace the load-deflection response, cracking pattern and ultimate shear strength of the tested reinforced hybrid concrete beams with or without construction joint. afterward, a parametric study has been conducted to investigate the effects of many important variables (compression strength for (hsc) layer, thickness of (hsc) layer, shear span to effective depth ratio ( ), thickness of resin bond layer). comparison between the analytical and experimental results has shown a reasonable agreement of the load-deflection response, where, the average of the maximum difference in first cracking and ultimate loads was (13)% and (9.6)%, respectively. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 التحليل الالخطي لألعتاب الخرسانية المسلحة العميقة الهجينةالتقصي العملي و الخالصة من الخرسانة ةلعتبات الخرسانية المسلحة العميقة المصنوعفي السلوك القص العام ايــ وعمل اــ نظري اــ بحث تقــدم هذه الدراسة تضمن الجزء .( في منطقة الضغطhsc( في منطقة الشد والخرسانة عالية المقاومة )nscالهجينة :الخرسانة عادية المقاومة) أحد هذه .موديالت من األعتاب الخرسانية المسلحة العميقة الهجينة تحت تأثير فحص نقطي ثنائي التحميل ةالعملي فحص تسع ( لدراسة تأثيرات: سمك طبقة bو aاألخرى قسمت إلى مجموعتين ) والعتبات الثمانيةإرشادية العتبات فحصت كعتبة أي وجود ) مباشرة أو في أوقات مختلفة ( وطريقة الصبweb( , وجود حديد تسليح الوترة )hscالخرسانة عالية المقاومة ) وأنماط الفشل. )المطيلية( أفقي( على مقاومة القص العظمى, حمل التشقق, نمط التشقق, الهطول, المطاوعة إنشائيمفصل ينت إن العتبات المصنوعة من من تقنية التهجين المتبناة للخرسانة العادية والعالية المقاومة ب مستحصلةالعملي الالبرنامج نتائج لها مقاومة القص العظمى الكلي (% من عمق العتبة 50-25في منطقة الضغط بسمك ) mpa 45) ) الخرسانة العالية المقاومة على ذات تسليح الوترة ,عتبات ل(% ل22.25 -16.75 و ) للعتبات بدون تسليح الوترة (% 19.5-11.2زادت بنسبة حوالي ) (% للعتبات بدون ومع تسليح الوترة , 57.9 43.4(% و) 4832.8حمل التشقق األول زاد بنسبة حوالي ). كذلك التوالي على التوالي. (% و) 22.6-13.3العتبات الهجينة المفحوصة )المصبوبة بشكل مباشر( أبدت زيادة في المطاوعة )المطيلية( بنسبة حوالي ) بينما العتبات الهجينة)ذات المفصل اإلنشائي مع وجود طبقة .الوترة, على التوالي(% للعتبات بدون ومع تسليح 17.3-26.3 (% للعتبات بدون 30.2(% و )28.7ملم( أبدت زيادة اكبر في المطاوعة بنسبة حوالي ) 1من مادة االيبوكسي بسمك حوالي .ومع تسليح الوترة, على التوالي ( لتقصي ansysثالثية األبعاد الخطية في برنامج العناصر المحددة ) ,تم استخدام عناصر محددة تحليليفي الجزء ال بدون أو العظمى للعتبات الخرسانية العميقة المسلحة الهجينة مع القص الهطول, نمط التشقق و مقاومة-الحمل منحني تصرف ــ االعملية والتحليلية أبدت توافقالمقارنة بين النتائج .عديدة مهمة وجود مفصل إنشائي باإلضافة إلى دراسة تأثير متغيرات (% و 11نسبة حوالي )ذو الفارق األعظم في حمل التشقق األول والحمل األقصى , حيث كانالهطول-في منحني الحمل ال معقو (% , على التوالي.6,9) 1. introduction deep beams are structural elements loaded as beams but having small shear span to depth ratio. a deep beam in general, has a depth much greater than the normal, while the thickness in the perpendicular direction is much smaller than either span or depth. (aci-code 318r-08) defines deep beams as those, which have clear span to overall depth ratio less than four ( ⁄ ), or the shear span to effective depth ratio less than two ( ⁄ ), and should be loaded on one face and supported on the opposite face, so that the compression struts can develop between the loads and supports. reinforced concrete deep beams are widely used in many structural engineering applications, such as: transfer girders, pile caps, offshore structures, shear walls, wall footing, floor diaphragms and complex foundation system (asce committee 426). utilization of high strength concrete in construction sector has increased due to its improved mechanical properties compared to ordinary concrete. one such mechanical property, shear resistance of concrete beams is an intensive area of research (sudheer et al., 2011).the relatively recent development in concrete technology has led to produce high compressive strength concrete of (40 to 150 mpa). high strength concrete can be produced by adding high range water-reducing admixtures (superplasticizer) and/or other admixtures (silica fume or fly ash) to portland cement concrete (newman and choo, 2003). although high strength concrete offers advantages in terms of performance and economy of construction, the brittle behavior of the material remains a major drawback in some structural applications especially in earthquake resistant structures. since strength and ductility of concrete are inversely proportional, high strength concrete is significantly more brittle than the normal strength concrete (ashour and wafa, 1993). in order to overcome the problems in terms of al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 010 deformability and ductility of concrete beams reinforced with steel bars, alternative solutions of using hybrid concrete concept is presented in this study. 2. objective of research this work is intended to introduce experimental investigation of the ultimate shear strength, cracking patterns, modes of failure, deflection and ductility of hybrid reinforced concrete deep beams composited of hsc in compression zone and nsc in tension zone. the two types of concrete will be either cast monolithically (at same time) or cast with horizontal construction joint (at different times).the effects of high strength concrete layer, web reinforcement and construction joints on overall shear behavior will be studied. evaluate the validity and accuracy to carry out finite element model to analyze the nonlinear behavior of reinforced hybrid concrete deep beam up to failure by using ansys computer program. as well as, parametric study of many important variables, such as: compressive strength of (hsc) layer, depth of (hsc) layer, shear span to effective depth ratio and thickness of resin bond layer. 3. description of specimens the experimental study consists of examining the use of two test groups (a and b). all beams are designed to fail in shear prior to flexure according to (aci–318code) specifications. group (a) had no web reinforcement, while group (b) included web reinforcement. the two test groups (a and b) are made of two different concrete mixes which are (25 and 45) mpa with normal and high strength concrete at tension and compression zones, respectively. for the two groups, eight models of deep beams are tested and the main parameters were identified to be: thickness of hsc layer in compression zone (25 and 50) % of total depth, shear reinforcement ratio (0.0 and 0.5)% and presence of construction joint. the type of concrete at tension zone and longitudinal reinforcement ratio are kept constants. designation and details of all test beams are reported and presented in table (1). test specimens having a total length (l=1400mm), span length (ln=1200mm), overall depth (h=450mm), effective depth (d=400mm) and width (b=100mm) with shear span to effective depth ratio (a/d) about 1.0 to ensure that tied-arch action of deep beam would be developed. four (ø12mm) diameter of deformed bars were provided as longitudinal tension reinforcement with about 1.13%) and (2ø10mm) to be used as compressive bars. the vertical and horizontal shear reinforcement were omitted from the beams of group (a) to emphasize the effect of high strength concrete layer without stirrups on shear capacity of hybrid deep beam, while the beams of group (b) minimum vertical and horizontal web reinforcement (ø4mm @100 mm c ∕c) with shear reinforcement ratio about (0.5%) were used to study their effect on shear capacity for hybrid beam, as shown in figure (1). material properties the cement used in casting all the specimens was ordinary portland cement company commercially known (tasluja-jesser). also, natural sand from (wlait-ali) region was used as a fine aggregate. the fine aggregate was sieved at sieve size (2.36mm) to separate the aggregate particle of diameter greater than 2.36mm. locally available gravel of 19 mm maximum size was used. clean tap water was used for casting and curing of all the specimens. normal strength concrete was used to cast all specimens with different percentage of cross-section depth. it was decided to choose a mix of 1:1.41:2.64 (by weight) cement, sand, gravel, respectively and 0.41water cement ratio. the compressive strength of nsc was about 25 mpa at age of (28 days). the employed chemical admixtures (superplasticizer), low water-cement ratio and high cement content make the design of high strength concrete a highly critical process than the design of al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 normal strength mixtures. therefore, several trial mixes have been made through the earlier stage of the present work. the high strength concrete mix is given a compressive strength of about (45mpa) at age (28 days). the yield strength of steel (fy) for bar size (12, 10, 4 mm) was (643, 596, 568 mpa) respectively with the value of modulus of elasticity was taken as (200 gpa) for all sizes. the mechanical properties of the superplasticizer (glenium 54) and epoxy resin (concresive 1414) sheet are given in table (2) according to manufacturing specifications of basf company, dubai. 4. test setup the hydraulic universal testing machine was used to test the beam specimens as well as the control specimens. the testing machine has a capacity of (2000 kn) available in the structural laboratory in civil engineering department, college of engineering, al-qadissiya university, as shown in figure (2). 6. experimental results 6.1 cracking patterns in general, there are three stages of load-deflection response, these are: elastic-uncracked, elasticcracked and ultimate stage, where the first stage terminates when the cracks develop. on the other hand, there are three types of developed cracks, flexural cracks, flexure-shear cracks and inclined (diagonal) shear cracks, as shown in figure (3). the specimen a-1n is made from normal strength concrete for overall depth and does not include web reinforcement (stirrups). the first visible cracks are narrow diagonal shear cracks in the shearspan region formed at a load of about (125kn). a few flexural cracks formed later at mid span region at a load of about (200kn). then the collapse happened suddenly by splitting the beam into two pieces at load about (374kn). the specimen b-1sn is made from normal strength concrete for overall depth; it is similar to the specimen (a-1n) except including of web reinforcement (stirrups). firstly, the formation of diagonal crack through shear span was started at a load of about (145kn). when the load reached about (208kn) the narrow flexural cracks appeared at constant moment region. as the load increased the diagonal cracks developed. afterward, the failure occurred due to concrete crushing along strut direction at ultimate load about (400kn). it can be noticed that the specimen (b-1sn) has larger shear capacity when compared with the specimen(a-1n) by about(7%) and larger stiffness of post-cracking response and also lesser deflection at service load (65% from ultimate load) about (18.2%). the specimens cast monolithically (a-2nh25, a-3nh50) are made from two types of concrete, normal strength concrete (nsc) and high strength concrete (hsc) with (25% and 50%) of overall depth at compression zone, respectively. for specimens (a-2nh25 and a-3nh50), diagonal cracks formed initially at a load approximately of (166kn) and (185kn) (40% and 41.4% of peak load), respectively, and larger than the specimen (a-1n) by about (32.8% and 48%), respectively the increase in first cracking loads may arise from the increase in beam stiffness due to the increase in the ultimate compressive strength of compression zone. a flexural crack formed at a load about (208kn) for specimen a-2nh25 in a constant moment region, and remained a narrow width through the test, while in the specimen (a-3nh50) flexural cracks are not observed. finally, the diagonal-splitting failure occurred at a load about (416 and 447kn) for specimens (a-2nh25 anda-3nh50) which are larger about (11.2% and 19.5%) with respect to control beam (a-1n), respectively, as shown in figure (3) and table (3). the specimen cast with construction joint (a-4nh25e) is made from (nsc) in tension zone and (hsc) in compression zone of thickness (25%) of total depth. the specimen is similar to the al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 specimen (a-2nh25) in all details, but the difference was existence of the construction joint with epoxy resin layer positioned between two layers of concrete to provide adequate bond between them. this case may be important during concrete structures maintenance, where the layers of new concrete are often applied to an old structure in order to repair and /or strengthen structural element. in general, the first visible cracks are inclined shear cracks at load about (145 kn) (36.7% of the ultimate load) and larger than the specimen (a-1n) by about (16%) due to increase in the ultimate compressive strength of compression concrete zone. finally, the diagonal splitting failure is occurred prior to appearance of the flexural cracks at ultimate load about (395kn), which increased about (5.6%) with respect to control specimen (a-1n). the specimens cast monolithically, (b-2snh25, b-3snh50) are made from two types of concrete, (nsc) in tension zone and (hsc) at compression zone of thickness (25% and 50%) of total depth, respectively. these specimens are similar to the specimens (a-2nh25 and a-3nh50) in all details, but the difference is existence of minimum horizontal and vertical (ø4mm @ 100 mm ⁄ ) shear reinforcement. this model of hybridization for specimens (b-2snh25 and b-3snh50) have increased the first crack loads about (43.4% and 57.9% with respect to the control specimen b-1sn), respectively. the increase in first cracking loads may arise from the increase in beam stiffness due to the increase in the ultimate compressive strength of compression zone and existence of web reinforcement. when the loading level increased, the diagonal cracks developed and the concrete at strut direction and under loading plate is crushed at load about (467and 498kn) for specimens (b2snh25 and b-3snh50), respectively. the ultimate load for these specimens increased about (16.75% and 22.25%) with respect to the control specimen (b-1sn), respectively, as listed in table (3). the specimen cast with construction joint (b-4snh25e) was cast in two stages with interval carnal (28 days). first, the normal strength concrete (nsc) part was cast at bottom tension zone and after its final hardening, the high strength concrete (hsc) layer was cast later at compression zone (25% of total depth) after the epoxy layer was put to provide adequate bond between two different concrete layers. the first visible crack is inclined shear crack a long strut direction at load about (166kn) (37% of the ultimate load). on the other hand, the first cracking load of this specimen increased about (14.5% of control beam b-1sn) due to the increase in moment of inertia of gross section, while it decreased about approximately (20.2% of similar specimen b-2snh25) due to the presence of the construction joint which reduced the stiffness of the beam, and then reduced the cracking load. as the load increasing, the diagonal cracks developed and widened rapidly toward supporting and loading points, and then the diagonal strut compression failure and crushing of concrete occurred along line that join support and point load at load about (447kn), as shown in figure (3). 6.2 load-deflection curves all the beams of this study were designed to fail in shear according to (aci-318code) because the mechanical behavior and design of deep beams are governed by shear and its load carrying capacity depends on the strength of compressive strut that join the loading and reaction points (tied-arch action). in general, there are three stages of load-deflection response, these are: elastic-uncracked, elasticcracked and ultimate stage, where the first stage terminates when the cracks develop. in elasticuncracked stage, deflection increase linearly in all beams with loading since the materials in compression and tension zone are in elastic manner. in elastic-cracked (post-cracking) stage there is also linear relationship between load and deflection but with reduction in slope. after this stage, the slope decrease largely and aggravated increments in deflection with small increase in loading level up to failure. load – deflection curves for two groups are shown in figure (4). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 6.3 ductility ductility can be defined as the ability to sustain inelastic deformations without losing of the load carrying capacity prior to failure. in the present study, the experimental ductility ratios are calculated according to the deflection at ultimate load divided by the deflection at yielding (winter and nilson, 1978). table (4) illustrates the ductility ratio of the tested beams. for specimens of series a, (a-2nh25, a-3nh50 and a-4nh25e) which had high strength concrete in compression zone (25%, 50% and 25% with construction joint) of total depth, respectively, the ductility was increased (13.3% , 22.6% and 28.7%), respectively, in comparison with control beam (a-1n),while the specimens of series b,(b-2snh25, b-3snh50 and b4snh25e), had high strength concrete in compression zone (25%, 50% and 25% with construction joint) of total depth, respectively, the ductility was increased (17.3%, 26.3% and 30.2%), respectively in comparison with control beam(b-1sn). the increase in the ductility can be attributed to the slight increase in ultimate load capacity, which produces higher ultimate deflection, and also due to the presence of construction joint between two types of concrete, which decreased the beam stiffness, and then increased the ultimate deflection. 7. numerical analysis the aim of this section is to compare between the finite element model results and the experimental results to verify the adequacy of elements type, material modeling, and convergence criteria to model the response of the reinforced hybrid concrete deep beams, which consist of different types of concrete (nsc and hsc), with or without web reinforcement and with or without construction joints. this section includes the analysis of the tested beams and parametric study of many variables by using a powerful nonlinear finite element method package ansys software (version 12.0). 7.1 description of specimens in finite element by taking advantage of the symmetry for both beam’s geometry and loadings, a quarter of the beam was used for finite element analysis, as shown in figure (5). an important step in finite element modeling is the selection of the mesh density. a convergence of results is obtained when an adequate number of elements are used in a model. this is practically achieved when an increase in the mesh density has a negligible effect on the results. therefore, in this finite element modeling, a convergence study is carried out to determine an appropriate mesh density. three types of mesh are used to find the best mesh size for control beam (a-1n) and hybrid beam (a-2nh25). figure (6) shows the relationship between the number of elements and mid-span deflection. it can be observed from the figure below that the difference can be neglected when the number of elements increased from (1138) to (4182) for the control deep beam, from (1194) to (4294) for the hybrid beam; therefore, the (1138 and 1194) models select for model the a-1n and a-2nh25, respectively. 7.2 modeling of reinforced concrete control beam in the finite element model, a solid element (solid 45) was used to model the steel plates at the support and loading point. in addition, (solid 65) was used to model the two types of concrete. node to node contact elements were used to model construction joints between two types of concrete old pre-cast (nsc) and new cast-in-place (hsc), as shown in figure (7). link-8 element was employed to represent the steel reinforcement for group (a) and (b), as shown in figure (8). in this study, a perfect bond between concrete and steel reinforcement is assumed. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 boundary conditions need to apply at points of symmetry and where the supports and loads exist. to model the symmetry, nodes on these planes must be constrained in the perpendicular directions. therefore, the nodes in ux and uz have a degree of freedom equal to zero for plane of midspan and plane of longitudinal, respectively, as shown in figure (9). the support was modeled in such a way as a roller. a single line of nodes on the plate is given constraint in the uy direction. by doing this, the beam will be allowed to rotate at the support. the external distributed applied load was represented by dividing the total distributed load on the top nodes according to area rounded of each node to represent the distributed load in ansys program. figure (10) shows the details of applied load at loading plate. 7.3 results of finite element analysis all tested beams will be analyzed by using ansys computer program, as mentioned previously. this comparison includes: first cracking load, cracking patterns, ultimate load and deflections at service and ultimate load. 7.3.1 first cracking loads the comparison between experimental and numerical results of the first cracking load is shown in table (5). table (5) shows a reasonable agreement in the comparison between the experimental cracking loads of the beams, , and the numerical cracking loads from the finite element models, .the first cracking load obtained from numerical data showed results lower than the experimental data recorded with difference about (13%) as an average. 7.3.2 load-deflection response deflections (vertical displacements) were measured at mid-span at the center of the bottom face of the beams. the load versus deflection plots for all beams obtained from the numerical study together with the experimental plots are presented and compared in figure (11). a relatively stiffer numerical response has been observed at the advanced stages of loading. as a general response, the load deflection plots for the beams from the finite element analysis gave an acceptable agreement when compared with the experimental data, where the three stages of loaddeflection response (elastic-uncracked, elastic-cracked and elasto-plastic) can be noticed. 7.3.3 ultimate shear strength table (6) shows the comparison between the ultimate loads of the experimental (tested) beams and the numerical models from finite element analysis. it is clear that the loads obtained from numerical simulation gave acceptable convergence with the corresponding values of the experimental test beams with different (9.6%), as shown in the table below. 7.3.4 ultimate and service mid-span deflections a comparison between mid-span deflections at ultimate and service load of the experimental tested beams with numerical mid-span deflection from finite element models, where the service load equal (0.65×ultimate load) (kheder et al., 2010), is shown in table (7). as shown in table (7), in comparison with the experimental values, the numerical models showed increasing in ultimate deflections for the all beams about (18.7%) as an average, while the al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 deflections at service load are lower than the experimental data recorded with difference about (9.8%) as an average. 7.4 parametric study the effect of some selected parameters on overall shear behavior of homogenous and hybrid cross section deep beams are decided herein, as follows: 1compressive strength for high strength concrete (hsc) layer. 2thickness of high strength concrete (hsc) layer. 3shear span to effective depth ratio ( ). 4thickness of resin bond layer. 7.4.1 effect of compressive strength for high strength concrete (hsc) layer to show the effect of compressive strength of high strength concrete layer, two cases (a, b) were studied. when the strength of high strength concrete layer increased from (25-200) mpa, the ultimate capacity increased largely about (21.8 66, 30.5 -80, 24.7 77.8, 35 83) % for the specimens (a-2nh25, b-2snh25, a-3nh50 and b-3snh50), respectively with higher stiffness and ultimate deflection, as shown in figure (12). 7.4.2 effect of thickness for high strength concrete (hsc) layer to explain the effect of thickness for hsc layer, two groups (a and b) were studied with varied of hsc depth to (25%, 50%, 75%, and 100 %) of total specimen depth. in general, when the hsc layer thickness increased causing increment in the beam stiffness and then led to failure at high level of ultimate load with slight increasing of mid-span deflection, as shown in figure (13). 7.4.3 effect of the shear span to effective depth ratio ( ) to show the effect of the shear span to effective depth ratio ( ), four specimens (a-2nh25, a3nh50, b-2snh25 and b-3snh50) were studied with varied ( ) to (0.5, 0.75, 1, 1.25) for each specimen, as shown in figure (14) and table (8). 7.4.4 effect of resin bond layer to explain the effect of thickness of epoxy resin layer, two specimens (a-4nh25e and b4snh25e) were studied changing the epoxy resin thickness to (1, 2 and 3) mm. in general, when the gap between two types of concrete of these specimens that was full of the epoxy resin increased to (1, 2 and 3)mm, the ultimate load decreased about (5 27.7)% and (3 20.9)% for specimens (a4nh25e) and (b-4snh25e), respectively with increasing in service mid-span deflection, as shown in figure (15). al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 8. conclusions 8.1 conclusions for experimental work 1presence of high strength concrete (hsc) layer in compression zone with thickness (25 and 50)% of total depth led to increase the ultimate shear strength by about (11.2 and 19.5)%for specimens without web reinforcement (group a) and about (16.75 and 22.25)%for specimens with minimum web reinforcement(group b),respectively. 2the first cracking loads were increased by about (32.8 48) % for specimens of (group a) and about (43.4 57.9)% for specimens of (group b) due to hybridization technique. 3 presence of construction joint in hybrid sections produced slight reduction in ultimate shear strength about (5 and 4.3) % for specimens without and with web reinforcement, respectively, when compared with hybrid sections cast (monolithically). this means that the casting technique (wet-on-wet) is favorable. 4 the tested hybrid beams with (hsc) layer that had no web reinforcement exhibited an increase in ductility between (13.3% 22.6%), while the tested beams that had minimum web reinforcement exhibited larger increasing in ductility between (17.3% 26.3%). 5presence of construction joint with epoxy resin layer of thickness about (1mm) caused increasing in ductility about (28.7%) for specimen without web reinforcement and about (30.2%) for specimen with web reinforcement. 6for hybrid deep beams of (nsc) and (hsc) without web reinforcement, the mode of failure was splitting. while the hybrid deep beams with minimum web reinforcement, the mode of failure altered from splitting to crushing or compression of strut. 8.2 conclusions for finite element analysis 1the general behavior of the finite element models represented by the load-deflection plots at mid-span showed acceptable agreement with results of experimentally tested beams, where the deflections at service load were lower than the experimental data recorded with difference about (9.8%) as average. 2the ultimate shear loads predicted by the numerical analysis were close to that measured during experimental testing with maximum difference (9.6%) as average. 3the first cracking load obtained from numerical data showed results lower than the experimental data recorded with difference about (13%) as average. 4the ultimate shear strength for hybrid reinforced concrete deep beams increased about (21.8-77.8 and 30.5-83) mpa for specimens of group a and b when the compressive strength of (hsc) layer increased from (25-200) mpa, respectively, with higher stiffness and ultimate deflection. 5 when the thickness of hsc layer increased to (25, 50, 75, 100)% of total depth, the ultimate load increased about (12.8, 18.6, 49.5, 73.4) % for group (a), while it increased about (16.6, 24,71.3,97.2)% for group (b), respectively. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 011 6the specimens with full (hsc) section have more ultimate shear strength than hybrid section but less ductility. 7the ultimate load decreased about (6.3-19.6)%, when the shear span to effective depth ratio ( ) increased about (0.5-1.25) of the tested beams but the service load deflection increased about (15.4-57.4)%. 8the ultimate load decreased about (5-27.7) % and (3-20.9)% for specimens(a4nh25e)and(b-4snh25e),respectively with increasing in service mid-span deflection when the epoxy resin thickness changed to (1, 2 and 3) mm. references [1] aci-asce committee 426, "shear strength of reinforced concrete members ", proceedings, asce 1973; 99(6), pp. 1091-1187. [2] ansys, "ansys help", release 9.0, copyright 2004. [3] ashour, s.a., and wafa, f.f., "flexural behavior of high strength fiber reinforced concrete beams", aci structural journal, vol. 90, no. 3,may-june 1993, pp. 279-287. [4] concresive," 1414 epoxy bonding agent for concrete repairs, bonding concrete to concrete, steel and granolithic toppings", technical data sheet, edition 2, 2006. [5] glenium," 54 a high performance concrete superplasticiser based on modified polycarboxylic ether", technical data sheet, edition 2, 2010. [6] newman, j., and choo, b.s., "advanced concrete technology", edition,elsevier ltd., uk 2003, (616) p. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 019 table (1): designation and details of test beams group beam no. beam designation depth of concrete construction joint * nsc (mm) hsc (mm) (a) hybrid deep beams without web reinforcement a-1 a-1n 450 ----without a-2 a-2nh25 337.5 112.5 without a-3 a-3nh50 225 225 without a-4 a-4nh25e 337.5 112.5 with (b) hybrid deep beams with web reinforcement b-1 b-1sn 450 ----without b-2 b-2snh25 337.5 112.5 without b-3 b-3snh50 225 225 without b-4 b-4snh25e 337.5 112.5 with * without: casting of (hsc) and (nsc) layers at same time (monolithically). with: casting of (hsc) and (nsc) layers at different time. where each symbol in table (1) refers to: a, b: group symbol, 1-4: sequence of specimen in its group, n: normal strength concrete, h: high strength concrete, 25, 50: thickness of high strength concrete layer 25%, 50% of total depth, e:epoxy resin existence between two types of concrete, s: existence of web reinforcement (stirrups). table (2): properties of superplasticizer and epoxy resin. commercial name glenium 54 chemical composition sulphonated melamine and naphthalene formaldehyde condensates subsidiary effect increased early and ultimate compressive strength concrete with minimal voids and optimum density form whitish to straw coloured liquid relative density 1.07 ph 5-8 chlorides free from chlorides properties concresive®1414 mixed density @ 25°c 1485kg/m³ pot life 25°c 2 hours 40°c ¾ hours tack free time 25°c 9 hours 40°c 5 hours full cure 7 days al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 table (3): cracking load, ultimate load and failure modes of the tested beams. mode of failure ultimate load,pu (kn) cracking load,pcr(kn) beam symbol flexure crack shear crack diagonal splitting ------374 -----200 125 a-1n diagonal splitting 11.2 416 32.8 208 166 a-2nh25 diagonal splitting 19.5 447 48 ------185 a-3nh50 diagonal splitting 5.6 395 16 ------145 a-4nh25e strut crushing ------400 -------208 145 b-1sn strut crushing 16.75 467 43.4 239 208 b-2snh25 strut crushing 22.25 498 57.9 225 229 b-3snh50 diagonal compression 11.75 447 14.5 218 166 b-4snh25e i :-considered beam , r:reference beam table (4): ductility ratio of tested beams. μ ductility ratio, ( ) ultimate deflection, ∆ (mm) yielding deflection, ∆ (mm) beam symbol ------1.5 5.25 3.5 a-1n 13.3 1.7 7 4.1 a-2nh25 22.6 1.84 7.75 4.2 a-3nh50 28.7 1.93 7.45 3.85 a-4nh25e ------1.79 5 2.8 b-1sn 17.3 2.1 6.3 3 b-2snh25 26.3 2.26 7.25 3.2 b-3snh50 30.2 2.33 6.75 2.9 b-4snh25e = ductility of considered beam * = ductility of reference beam al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 000 table (5): experimental and numerical results of first cracking loads beam no. first cracking load (kn) experimental numerical shear crack flexure crack shear crack flexure crack a-1n 125 200 112 141 0.9 a-2nh25 166 208 143 150 0.86 a-3nh50 185 ------154 176 0.83 a-4nh25e 145 ------124 189 0.86 b-1sn 145 208 126 151 0.87 b-2snh25 208 239 192 149 0.92 b-3snh50 229 225 198 143 0.86 b-4snh25e 166 218 149 144 0.9 the average 0.87 table (6): comparison between experimental, finite elements ultimate shear loads. beam no. ultimate shear load (kn) a-1n 374 414 1.106 a-2nh25 416 467 1.122 a-3nh50 447 491 1.098 a-4nh25e 395 446 1.129 b-1sn 400 439 1.097 b-2snh25 467 512 1.096 b-3snh50 498 544 1.092 b-4snh25e 447 459 1.027 the average 1.096 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 table (7): comparison between experimental and numerical deflections at service and ultimate loads. beam no. mid-span deflection(mm) at service load at ultimate load a-1n 2.5 2.15 5.25 6.75 0.86 1.286 a-2nh25 2.42 2.12 7 7.68 0.876 1.097 a-3nh50 2.3 1.95 7.75 9.2 0.848 1.187 a-4nh25e 3.2 3.15 7.45 8.84 0.984 1.186 b-1sn 2.2 2.1 5 5.82 0.954 1.164 b-2snh25 2.12 2.05 6.3 7.54 0.967 1.197 b-3snh50 2 1.65 7 8.69 0.825 1.241 b-4snh25e 2.5 2.25 6.75 7.73 0.9 1.145 the average 0.902 1.187 table (8): effect of shear span to effective depth ratio ( ) on the numerical ultimate load and mid-span deflection at service load. increase of deflection at service load % decrease of ultimate load % numerical mid-span deflection at service load (mm) numerical ultimate load(kn) ⁄ beam no. ----------1.62 543 0.5 a-2nh25 22.2 9 1.98 495 0.75 30.8 14 2.12 467 1 57.4 22 2.55 423 1.25 ----------1.51 565 0.5 a-3nh50 16 8.5 1.75 517 0.75 29.1 13 1.95 491 1 49 19.6 2.25 454 1.25 ----------1.58 587 0.5 b-2snh25 19 7.2 1.88 545 0.75 29.7 12.8 2.05 512 1 55.1 15.5 2.45 496 1.25 ----------1.3 618 0.5 b-3snh50 15.4 6.3 1.5 579 0.75 26.9 11.9 1.65 544 1 48.4 13.3 1.93 536 1.25 al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 figure (1): loading and specimens details; (a)series a (without web reinforcement) (b)series b (with web reinforcement) figure (2): testing machine used in this work. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 0 100 200 300 400 500 0 5 10 lo a d ( k n ) def. at mid span (mm) a-1n a-2nh25 a-3nh50 a-4nh25e 0 100 200 300 400 500 600 0 5 10 lo a d ( k n ) def. at midspan (mm) b-1sn b-2snh25 b-3snh50 b-4snh25e figure (3): crack patterns of all specimens. figure (4): load – deflection cures for groups a, b. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 0 0.5 1 1.5 2 2.5 0 2000 4000 6000 m id ‐s p a n d e fl e ct io n m m no. of elements a-1n a-2nh25 figure (5): adopted quarter of the deep beam. figure (6): results of convergence study. figure (7): mesh of the concrete, steel plate, and steel support for the hybrid beam. figure (4) load – deflection cures for group a. al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 figure (8): details of reinforcing steel bars: (a) group a, (b) group b. figure (9): details of boundary conditions (symmetry and supports) for the quarter of the control beam figure (10): details of the applied load at the loading plate. (a) (b) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 0 100 200 300 400 500 0 2 4 6 8 lo a d ( k n ) def. at mid span (mm) a-1n exp. fem 0 100 200 300 400 500 0 5 10 lo a d ( k n ) def. at mid span (mm) a-4nh25e exp. fem 0 100 200 300 400 500 600 0 5 10 lo a d ( k n ) def. at mid span (mm) a-3nh50 exp. fem 0 100 200 300 400 500 600 0 2 4 6 8 lo a d ( k n ) def. at mid span (mm) b-2snh25 exp. fem 0 100 200 300 400 500 600 0 5 10 lo a d ( k n ) def. at mid span (mm) b-3snh50 exp. fem 0 100 200 300 400 500 0 2 4 6 8 lo a d ( k n ) def.at mid span (mm) b-1sn exp. fem 0 100 200 300 400 500 0 5 10 lo a d ( k n ) def. at mid span (mm) b-4snh25e exp. fem 0 100 200 300 400 500 0 5 10 lo a d ( k n ) def. at mid span (mm) a-2nh25 exp. fem figure (11): load-deflection curve for the two groups; a, b al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 001 0 100 200 300 400 500 600 700 0 5 10 lo a d ( k n ) def. at mid span (mm) a-2nh25 f'c=25mpa f'c=45mpa f'c=75mpa f'c=100mpa f'c=200mpa 0 100 200 300 400 500 600 700 800 0 2 4 6 8 10 lo a d ( k n ) def. at mid span(mm) b-2snh25 f'c=25mpa f'c=45mpa f'c=75mpa f'c=100mpa f'c=200 mpa 0 100 200 300 400 500 600 700 800 0 5 10 15 lo a d ( k n ) def. at mid span (mm) a-3nh50 f'c=25 mpa f'c=45mpa f'c=75 mpa f'c=100 mpa f'c=200 mpa 0 100 200 300 400 500 600 700 800 0 2 4 6 8 10 lo a d ( k n ) def. at mid span (mm) b-3snh50 f'c=25 mpa f'c=45 mpa f'c=75 mpa f'c=100 mpa f'c=200 mpa 0 200 400 600 800 1000 0 5 10 15 lo a d ( k n ) def. at mid span (mm) depth of hsc (group b) 0.0% h 25% h 50% h 75% h 100% h0 200 400 600 800 0 5 10 15 lo a d ( k n ) def. at mid span (mm) depth of hsc (group a) 0.0% h 25% h 50% h 75% h 100% h figure (12): loaddeflection curves for hybrid beams; (a) 25% of total depth (hsc), (b) 50% of total depth (hsc) figure (13): loaddeflection curves for the tested two groups (a&b) (a) (b) al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 009 0 100 200 300 400 500 600 0 5 10 lo a d ( k n ) def. at mid span (mm) a-2nh25 a ∕ d =0.5 a ∕ d =0.75 a ∕ d =1.0 a ∕ d =1.25 0 100 200 300 400 500 600 0 2 4 6 8 10 lo a d ( k n ) def. at mid span (mm) a-3nh50 a ∕ d =0.5 a ∕ d =0.75 a ∕ d =1.0 a ∕ d =1.25 0 200 400 600 800 0 2 4 6 8 10 lo a d ( k n ) def. at mid span (mm) b-2snh25 a ∕ d =0.5 a ∕ d =0.75 a ∕ d =1.0 a ∕ d =1.25 0 200 400 600 800 0 5 10 lo a d ( k n ) def. at mid span (mm) b-3snh50 a ∕ d =0.5 a ∕ d =0.75 a ∕ d =1.0 a ∕ d =1.25 0 100 200 300 400 500 0 5 10 lo a d ( k n ) def. at mid span (mm) b-4snh25e t=0.0mm t=1mm t=2mm t=3 mm 0 100 200 300 400 500 0 5 10 15 lo a d ( k n ) def. at mid span (mm) a-4nh25e t=0.0mm t=1mm t=2mm t=3mm figure (14): loaddeflection curves for hybrid beams. figure (15): loaddeflection curves for hybrid beams. article al-qadisiyah journal for engineering sciences 12 (2019) 167–171 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: shahadmahdi2015@gmail.com (shahad al-obaidi) https://doi.org/10.30772/qjes.v12i3.606 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. study the effect of copper oxide nanoparticles on reduce crude oil sarah t. shakir a* and husham al-tameemi a a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 27 august 2019 received in revised form 23 september 2019 accepted 30 september 2019 keywords: reduce crude oil viscosity reduction drag reduction copper oxide nanoparticles a b s t r a c t in the transportation of fluid, the drag reducers in pipeline are important parameters because of drag reduction increased the ability of pump fluid when adding small amounts of additive to fluid. the frictional pressure loss in pipes is waste energy and it very costly so the drag reducing minimizes flow turbulence, reduces the costs of energy and increases throughput. the transportation of reducing crude oil is very difficult and needs some treatment to improve its transportation and this is because of its high viscosity. the purpose of this research is to study the effect of nanoparticles of copper oxide on viscosity of r.c. and other parameters when transport it through pipes. this research investigated the viscosity, pressure drop and other parameters in three pipes (0.0127, 0.01905 and 0.0254 m) i.d. with different concentrations (0.00625, 0.0125, 0.01875, 0.025 and 0.0375 (gm/l) w/v) at 50 oc and the flow rate is 50% of maximum. the results show that the performance of the drag reduction is much better in the larger pipes diameter than the smaller one. also, the cuo np's effect on r.c. viscosity and the maximum viscosity deviation is about 4%. in addition to cuo np's to r.c. has reduced the %dr, pressure drop and shear stress. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction reduced crude oil (black oil) (r.c.), is a product that is drawn from the bottom of the atmospheric distillation tower and has a boiling point above 425oc. reduced crude oil is the feedstock of vacuum distillation and the objective of vacuum distillation is fractionate reduce crude oil to derivatives and used it as base oil [1]. r.c. contains heavy components so that it is difficult to transport it, many techniques are used to improve it, and one of them is by adding different quantities of chemical additives like surfactant, polymer, and fiber [2,3]. 1.1. reducing viscosity when adding particles structure the using metal particles as a viscosity reducer for heavy oil/bitumen are contradicted the einstein’s [4] equation which relates the viscosity of dispersion medium (µo) and viscosity of dilute liquid suspension for noninteracting uniform of solid spheres (µ) : µ= µo (1+2.5ɸ) (1) if it does not consider any interaction between the oil and particles, which is one of the assumptions of this equation the contradiction may arise. however, the effect of interactions could not be major to overcome the increase of viscosity because of the physical effects such as given by eq.1. for that reason there will be an optimum concentration of the particles at which the effect of reactions is maximum which gives maximum viscosity reduction as a result of the applied particles metal type [5]. the revolution of nanotechnology science has attracted great attention http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i3.606 168 sarah t. shakir and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 167–171 for its important role in many applications in the oil & gas industry, for example, sensing or imaging, enhanced oil recovery, gas mobility control and other applications [6-8]. nanoparticles could be defined that are the materials that have one dimensioned range from 1 to 100 nm. also, submicron particles (<1000 nm) could be considered nanoparticles [7, 913]. a number of special properties that nanoparticle reveal corresponding to the bulk material. such as, the bending copper's bulk (wire, ribbon, etc.) take place with movement of copper atoms or clusters at approximately 50 nm scale. nano copper smaller than the 50 nm are considered as super hard materials that do not display the same flexibility such as bulk copper [14, 15]. nps have a very high surface area relative to volume ratio [14]. many researchers examine the effect of nps on viscosity by using different metal oxides and with a different technique. it has been observed that reduction of heavy oil viscosity was because of high temperature effect besides a series of chemical reactions known as aqua-thermolysis and these reaction change the physical properties [12]. clark et al. [11] discovered that the heavy oil viscosity is more reduced when aqueous metal salt is added into the process in comparison to steamonly experiments. li et al. [13] found that reduced viscosity, resin and asphaltene content of extra-heavy oil efficiently and that because of the effect of a nano nickel catalyst in viscosity reduction of liahoextra-heavy oil by aqua-thermolysis reaction. hamedi shokrlu and babadagli [5] studied the effect of nanosized metals on viscosity reduction of heavy oil/bitumen during thermal applications. haroun et al. [16] discovered that copper oxide are able to enhance injection water viscosity. ehsanollah ettefaghi et.al [17] concluded that no appreciable change in the oil's viscosity with respect to the engine oil without cuo nanoparticles. fabian bjørnseth [18] observed that no viscosity reduction occur-ring when added cu nanoparticles to heavy oil at different concentrations and temperatures. srinivasan and shah [19] were found that nanoparticles are definitely displayed ability for improving reservoir specific heat and thermal conductivity, as well their ability for enhancing density and viscosity of treatment fluids. s. afzal et.al. [20] found that addition of cuo nanoparticles to heavy oil has increased the viscosity at different concentrations at 50oc. hascakir et al. [21] investigated the effect of micron sized iron particles on heavy oil viscosity without steam treatment. chen et al. [22] studied the effect of nano-keggin-k3pmo12o40 on viscosity reduction in catalytic aqua-thermolysis of heavy oil and found that it changes in oxygen-containing groups essentially during the catalytic aqua thermolysis. the objectives of this research study the effect of copper oxide nanoparticles on r.c. viscosity, drag reduction and its effect on transportation r.c. in pipelines. 2. description of the flow system the system consists of three pipes with 0.0127, 0.01905 and 0.0254 m inside diameter with a length of 6 m made from carbon steel. as well as each pipe dividing to four pressure testing sections and the distance between each other is equal to 0.5 m. in addition the flow system contains two tanks, two pumps, flow meter, valves, digital thermometer, pressure gauges, and digital screen. these parts could be seen in fig. 1. figure 1. scheme of the experimental 1-open tank, 2receiving tank, 3pump, 4flow meter, 5, 6, 7pipe of 0.5, 0.75 and 1 inch, 8-valve, 9pressure gauge, 10-by-pass pipe, 11by-pass pipe connect with pump. 3. experimental work 3.1. material used: 3.1.1. copper oxide nanoparticles the properties of copper oxide nanoparticles are listed in table 1. table 1. physical properties of cuo nanopowder. chemical formula cuo appearance (color) black molecular weight 79.545 g/mol average particle size ≤ 50 nm appearance (form) powder surface area (m2/g) 25-40 nomenclature %dr percentage drag reduction u velocity of r.c. inside the pipe d diameter of pipe (m). δp pressure drop f friction factor δpb, δpa pressure drop before and after adding nano additives. l length of pipe (m). nps nanoparticles greek symbols r.c. reduce crude oil ρ density of r.c re reynold number τ shear stress sp.gr specific gravity τw wall shear stress (bar). sarah t. shakir and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 167–171 169 3.1.2. reduce crude oil the r.c. that used is taken from al-samawah refinery and the physical properties are shown in table 2. table 2. the physical properties of r.c. the viscosity @ 50 oc (c.st) sp.gr. api 252 0.93 20.65 3.2. experimental procedure: 1 fill the first tank with a sample of r.c. then run the system. 2 pump r.c. through pipes and record the initial readings of pressure for three pipes separately after closed other pipes. 3 add the amount of cuo nanoparticles to the first tank and recycle it for 30 minutes to ensure that the mixture is mixing well. 4. after that repeat step (2) to identify the improvement. 5 – for a continuous process, receiving tank and the second pump are being used to recycle r.c. to the first tank. 4. . results and discussion three parameters are studied in this research diameter of pipes, concentration and pressure drop. 4.1. effect of pipe diameter and reynolds number figures (2-6) display the effect of pipe diameter and reynolds number on % dr for different concentrations of cuo nanoparticles at 50 oc. as can be seen that %dr increased while shear stress decreased as pipe diameter increased at different concentration and this is due to increased area for interaction between r.c. and cuo nanoparticles [12,23]. the re, %dr, and τ are calculated by equations below: for laminar flow, fully developed in pipes (re <2300) for different sections areas: 𝑅ⅇ = 𝑢𝑑 𝑣 (2) %𝐷𝑟 = ∆𝑃𝑏−∆𝑃𝑎 ∆𝑃𝑏 ∗ 100 (3) 𝝉𝑤 = 𝑫𝜟𝑷 𝟒𝑳 (4) figure. 2. effect of pipe diameter on re at a different concentration at 50 oc. figure 3. effect of pipe diameter on shear stress at different concentrations and 50 oc. figure 4. effect of re on %dr at different concentration at 0.0127 m i.d. and 50 oc figure 5. effect of re on %dr at different concentration at 0.01905 m i.d. and 50 oc. figure 6. effect of re on %dr at a different concentration at 0.0254 m i.d. and 50 oc. 170 sarah t. shakir and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 167–171 as noticed from three figures above that %dr increased as re increased and that because of increasing the degree of turbulence inside the pipe when re increased which provide best media to the nanoparticles to be more effective. the increasing in %dr is occurred due to large eddies that absorb large amount of energy from the main flow, which be present in the pipe of large diameter. but in small pipes, the number of small eddies formed are larger than large eddies formed in large pipes. the small eddies required a large amount of absorbed energy from main flow to overcome the viscosity resistance and after that complete its shape. all small eddies do not absorb the same amount of energy, some of eddies absorb an adequate amount of energy and permit to overcome the resistance of viscosity, while the other absorb insufficient amount of energy and do not be able to overcome viscous resistance and in the end vanish which producing loss in the main flow energy. because of small eddies which absorbing small amount of energy the %dr in the small pipes is lower than in large pipes which do not allow it to overcome the viscosity resistance [12]. 4.2. effect of concentration from figures (7 and 8), it's clear that viscosity and pressure drop are decreased with increased concentration of cuo nanoparticles and this is because of breakage c-s bonds in asphaltene which is unstable and this is happening due exothermic chemical reactions between the oil phase and metal particles . the necessary energy for breaking these bonds could be as long as by exothermic chemical reactions between oil phase and metal particles [5, 21, 25]. figure 7. effect of conc. on viscosity at different pipes and 50 oc. as can be seen, there is an optimum concentration of cuo nanoparticles at which the viscosity reduction is maximum. it is noted that the decreasing that occur in pressure drop is a function of additives molecular weight, its concentration and flow rate. the pressure drop is very important as it is directly related to power requirements of the pump or fan for maintaining the flow [26]. figure 8. effect of conc. on pressure drop at different pipes and 50 oc. 4.3. friction factor figures (9-11) show the effect of re on friction factor as can be seen that the friction factor is calculated by two equations and the friction factor that is calculated by eq. 2. is smaller than in eq .1. 𝑓 = 64 𝑅ⅇ poisuell's equation (5) 𝑓 = 𝛥𝑝⋅𝑑∕4𝐿 𝜌⋅𝑢2 2⁄ fanning equation (6) figure 9. effect of re on friction factor at 0.0127 m i.d. and 50oc. figure 10. effect of re on friction factor at 0.01905 m i.d. and 50oc 0 0.02 0.04 0.06 0.08 0.1 181 183 185 187 f re fanning equation poisuell's equation 0 0.05 0.1 0.15 121 123 125 f re fanning equation poisuell's equation sarah t. shakir and husham al-tameemi /al-qadisiyah journal for engineering sciences 12 (2019) 167–171 171 figure 11. effect of re on friction factor at 0.0254 m i.d. and 50oc 5. conclusion  minimum viscosity values of 246cst at concentration 0.075 (gm/l) , 247cst at 0.075 (gm/l) and 242cst at concentrations (0.0375, 0.0625, 0.075) of cuo were obtained flowing in pipes of 0.0127 m. 0.01905 m and 0.0254m i.d. at 50°c respectively.  maximum% dr of 4.7269% at 0.0375 (gm/l), 13.04% at 0.0375 (gm/l) 36.842% at 6.25*10-3 (gm/l) and 0.0375 (gm/l) of cuo were obtained flowing in pipes of 0.0127 m. 0.01905 m and 0.0254m i.d. at 50°c respectively. acknowledgment all thanks and appreciation to petroleum research & development centre and al-samawah refinery for their helping and support this research. references [1] b. o. i. anas ghalib, zaki sultan,basra oil institute, amer star, kirkuk oil institute. heavy lubricants technology [to the competenceoperation and control / second stagetechnical diploma level]. available: http://koti.oil.gov.iq/files/library_files/refinery/heavey%20oil%20techni que%202nd%20class.pdf. 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[26] yunus a. çengel, j.m.c., fluid mechanics: fundamentals and applications. 2006: mcgraw-hill higher education, 2006. 0 0.05 0.1 0.15 0.2 91 93 95 f re fanning equation poisuell's equation 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 201 المتعرضة للحرارة نشاء نموذج رياضي لتخمين مقاومة االنضغاط ألنواع الخرسانة إ من الفحوص غير االتالفية العالية عباس سالم األميري كلية الهندسة / جامعة بابل 4102ايلول 0ُقبل 4102 ايار 14ُاستلم -ملخص البحث: حث بصورة أساسية ألعداد نموذج رياضي لتخمين مقاومة االنضغاط للخرسانة بنوعيها االعتيادية هذا البيهدف وذاتية الرص المعرضة للحرارة العالية من خالل إجراء الفحوص الالاتالفية والتي تشمل فحصي مطرقة شميدت روف االعتيادية بالدراسات فحص الذبذبات فوق الصوتية ، حيث النماذج الرياضية المقترحة للخرسانة بالظ و شملت الدراسة إعداد ثالثة .السابقة، ال تعطي الصورة الحقيقية لطبيعة الخرسانة المتعرضة للحرارة العالية multipleنماذج رياضية لكل نوع من الخرسانة ، اثنان منها تعتمد األسلوب التحليل االنحدار الخطي المتعدد ) linear regression analysis ) مع اختالف عدد العوامل المعتمدة بالنموذج ، اما الثالث فانه يعتمد ( باستخدام non linear regression analysisنموذج من التحليل االنحداري الالخطي ) إنشاءعلى .معادلة آسية مركبة ثنان منهما على للخرسانة االعتيادية ذات موثوقية عالية ، وتمتلك اإحصائية نماذج تم الحصول على وقد متغيرين فقط هو فحص مطرقة شميدت ، فحص الذبذبات فوق الصوتية وتكون اكثر عمليا من النموذج الثالث لعدم توفر المعلومات هالذي يعتمد على متغيرات عدة ، حيث يجد من الصعوبة في معظم الحاالت تطبيق هما والمتمثلة ليالرص مع اختالف نسبة الموثقية لكذج الخرسانة ذاتية افس النتيجة تم التوصل لنمبن. و لمطلوبةا بالمؤشرات اإلحصائية لكل نموذج. 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 202 construct a mathematical model to predict compressive strength of types of concrete (normal concrete and self compacting concrete ) exposed to high temperatures from nondestructive testing abbas al-ameeri babylon university-engineering college abstract nondestructive tests (ndt) are considered one of the methods of evaluation and quality control of concrete. in addition, nondestructive testing give, good indications about strength and durability of concrete samples and structural members. there are many studies about nondestructive tests for concrete nsc &hsc. so the fundamental aim of study is to construct a mathematical model to predict compressive strength of two types of concrete (normal concrete and self compacting concrete ) exposed to high temperatures from nondestructive testing ,by using (rebound number &ultrasonic pulse velocity). where mathematical models proposed for concrete normal conditions with previous studies, do not give a true picture of the nature of concrete exposed to high temperature. the study included the preparation of three mathematical models for each type of concrete, two of which are based method of multiple linear regression analysis with a different number of independent variables supported model, while the third, it depends on the construct of a model of non linear regression analysis using the exponentional equation . the statistical models for normal concrete was high reliability, and owns two of them on two variables only were to hammer schmidt test , ultrasonic pulse velocity test , and be more practical than the third model, which depends on several variables, where he finds it difficult in most cases empirical lack of information application . the same result was reached to models for self compacting concrete with a different rate of reliability for both types of concrete for statistical indicators of each model. التحليل االنحدار ، لصوتيةفحص مطرقة شميدت ، فحص الذبذبات فوق ا مقاومة االنضغاط ،:كلمات رئيسية التحليل االنحداري الالخطي ، الخطي المتعدد المقدمة -2 تعطي مؤشر جيد إنها إلىتالفية إحدى طرق التقييم والسيطرة النوعية للخرسانة باإلضافة إتعتبر الفحوص الال راسات حول الفحوص هناك العديد من الد .عن مقاومة وديمومة النماذج واألجزاء اإلنشائية الخرسانية إحصائي للتنبؤ نموذج إعداد تهدف هذه الدراسة تالفية للخرسانة التقليدية والخرسانة العالية المقاومة ، إالال بمقاومة االنضغاط للخرسانة بنوعيها االعتيادية والذاتية الرص المتعرضة إلى درجات الحرارة العالية ولمدد تالفية والمتمثلة بفحص مقدار االرتداد إعتماد على الفحوصات الالمختلفة من التعرض إلى الحرارة ، باال . وسرعة الذبذبات فوق الصوتية مجتمعةلمطرقة شميدت 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 203 استعراض البحوث -4 ( والتي binding material( مكونة بشكل أساسي مادة رابطة ) compositeالخرسانة هي مادة تركيبية ) أنواعها ومواد مالئة ممثلة بالركام الناعم والخشن معظمها يكون خامال ليست لها نشاط تمثل المواد األسمنتية ب . ,(neville , 1995 )هيدروليكي الحرارة على البنية التركيبية للخرسانة بشكل عام وعلى المادة السمنتيه بشكل خاص ،حيث درجات يؤثر ارتفاع التركيب البيني لـ)هايدرات الكالسيوم المائية ( ( dissolutionتؤدي الحرارة العالية إلى تفكيك ) (c-s-h( المسمى بهالم السمنت )jel الناتج ) تفاعل او تميأ السمنت مع الماء ، ينتج منه فقدان جزء من من ، حيث أوضحت (lankard et.al ,1971) من هايدرات الكالسيوم المائية dehydration)الماء البلوري ) م( °044-044%( عند ارتفاع درجات الحرارة ) 21-5ث إلى انخفاض كثافة الخرسانة بمقدار يتراوح ) البحو ود وج. كذلك تمتاز مكونات الخرسانة ب (umran ,2002 )بالمقارنة مع الخرسانة بدرجة الحرارة االعتيادية ك المكونات ، وتتجلى هذه الصفة والتي تؤثر بشكل كبير على عملية الترابط بين تل هاتمدد تمعامالبفروقات ( للنماذج عند التعرض إلى الحرارة العالية او اللهب spallingمن خالل حدوث ظاهرة االنفجار للخرسانة ) al-ameeri.&ahmed, 2013) ). إن هذا التدهور بخواص السمنت المتميأ يؤدي الى تدهور بخواص % ( ومقاومة 55-04يادية بشكل عام ، حيث تفقد الخرسانة من مقاومتها لالنضغاط بمقدار ) الخرسانة االعت م( بالمقارنة مع ° 544 -044( عند درجات الحرارة )21-12% ( ومعاير الكسر ) 54-15االنشطار بمقدار ) .(umran ,2002 )الخرسانة بدرجة الحرارة االعتيادية الخرسانة االعتيادية وذاتية الرص على حد سواء ، وكما أوضحا كما ان تأثير ارتفاع الحرارة على (helal & heiza ,2011 ) ان الخرسانة ذاتية الرص تتأثر بارتفاع الحرارة أكثر من الخرسانة االعتيادية تجانس بين رص نفسها ذاتيا مععلى تها العالية ي( نتيجة قابل voids،بسبب زيادة كثافتها وقلة الفراغات ) ، حيث كان انخفاض مقاومة االنضغاط ,(efnarc, 2005 )مكوناتها ،وزيادة المواد الناعمة والمالئة فيها درجات ارتفاع ( عند22-25% ( ومعاير الكسر ) 54-5% ( ومقاومة االنشطار بمقدار )52-25) بمقدار .(obeed, 2007) رة االعتياديةم( بالمقارنة مع الخرسانة بدرجة الحرا° 044 -044الحرارة ) جرى الفحوصات المختبرية على المنشات الخرسانية او على العينات الخرسانية من اجل تقيمها والوقوف على ت تالفية إلخواصها لتحقيق الديمومة لها على مدى طول عمر المنشأ الخرساني ، في الغالب تجرى الفحوصات ا مع التطور برزت الحاجة إلى استخدام فحوصات و المنشأ الخرساني . على النماذج الخرسانية من اجل تقيم تقيم المنشات القديمة او جديدة التشييد على حد سواء من دون اإلضرار بها ، منها لغرضا، أخرى جديدة تالفية ،هي فحوصات تجرى على المنشات لكي يتم و الفحوصات شبة اإلاتالفية إومن هذه الفحوصات الال هذه الفحوصات إن حيث . (2222)السامرائي ورؤوف ة منها في تقييم او استالم تلك المباني االستفاد المقاومة الموقعية للعنصر اإلنشائي، الكثافة ،امتداد التشققات المرئية والفراغات عنتالفية تعطي تصور إالال 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 204 خرساني ، وغيرها من ،وسمك العنصر اإلنشائي،إضافة إلى تحديد موقع حديد التسليح وسمك الغطاء ال التطبيقات لتلك الفحوصات ، ولكن األبرز من استخدامات هذه الفحوصات هي تحديد المقاومة الموقعية تالفية بشكل كبير على فحصي مطرقة شميدت إوتركزت تلك الفحوصات الال .( (iaea ,2002والديمومة (schmidt hammer ) ( و سرعة الذبذبات فوق الصوتيةultrasonic pulse velocity بشكل منفصل ) او بشكل مجتمع في تقييم المنشات والمباني ، من خالل مجموعة كبيرة من الدراسات منذ زمن ليس بالقصير يتم االستفادة منها في تقييم ،إعداد نماذج إحصائية ومعادالت من خاللعشرين ، البدأت في منتصف القرن ية إشغال وأمان المنشات القديمة او الحديثة التشييد. تلك الفحوصات و تحديد صالحلالنتائج في إيجاد عالقة بين مقاومة االنضغاط وفحصي 1999)رؤوف والسامرائي )من هذه الدراسات ما قام بها (.2-1مطرقة شميدت وفحص سرعة الذبذبات فوق الصوتية للخرسانة االعتيادية حسب المعادلة ) fcu =0.93rn 0.63 e 0.31v (2-1) .: سرعة الذبذبات فوق الصوتيةv، شميدت: ارتداد مطرقة rn: مقاومة االنضغاط ، fcuحيث : من مقاومة إلى إيجاد عالقة لتشمل نطاق واسع ( al-ameeri et.al,2013كذلك ما توصل إليه ) .(1-1االنضغاط للخرسانة االعتيادية حسب المعادلة ) fcu = 0.44 rn 0.65 e 0.55v (2-2) لالنضغاط وفحصي ( إلى إيجاد عالقة للخرسانة ذاتية الرص تربط بين مقاومتها hussam,2008كما توصل ) .(0-1مطرقة شميدت وفحص سرعة الذبذبات فوق الصوتية حسب المعادلة ) fcu = 0.0030 × rn 1.90 × upv 1.49 (2-3) الحرارة بالخرسانة بسبب تغير خواص يتأثر مقدار االرتداد لمطرقة شميدت وسرعة الذبذبات بارتفاع درجات و -24حيث رقم االرتداد لمطرقة شميدت ينخفض ) ، (umran ,2002 )الخرسانة المتعرضة لتلك الحرارة % ( عند 02-10م ( ، وكذلك سرعة الذبذبات تنخفض بمقدار )°544-044% ( عند درجة الحرارة )04 اما .( (karim ,2005ند درجة حرارة االعتيادية م(بالمقارنة مع الخرسانة ع°044-044درجة الحرارة ) م ( وكذلك °044-144% ( عند درجة الحرارة )04-0الخرسانة ذاتية الرص حيث رقم االرتداد ينخفض ) م (بالمقارنة مع الخرسانة عند ° 044-144% ( عند درجة الحرارة )02-5سرعة الذبذبات تنخفض بمقدار ) حيث ان انخفاض سرعة الذبذبات بارتفاع درجة الحرارة يأتي من . (ahmed ,2013 )درجة حرارة االعتيادية فقدان الماء البلوري والحر بهالم السمنت ، باإلضافة إلى عملية التسخين تودي الى توليد شقوق شعرية بسبب 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 205 التغيرات الحجمية نتيجة عملية التفكك لمكونات هالم السمنت ،وهذا التغير يودي الى حركة حرارية (thermal movement بين هالم السمنت والركام ، وهي ناتجة من الفروقات بين معامل التمدد لمكونات ) .( (nikolai,1971 الخرسانة تالفية إإحصائي يربط بين مقاومة االنضغاط وتلك الفحوصات الال نموذج وهنا تبرز الحاجة الى إعداد تقييم المنشات او العناصر اإلنشائية المتعرضة للحرارة او اللهب للخرسانة المتعرضة للحرارة العالية ، من اجل السابقة ال تلبي الحاجة لتقييم تلك الخرسانة التي النماذجعن طريق إجراء تلك الفحوصات ،حيث المعادالت او تعرضت إلى ظروف قاسية بعد ما تأثرت خواصها بشكل كبير. البرنامج العملي -3 karim,2005))، (umran ,2002 )اد نتائج الباحثين تم اعتم بحثفي هذه ال (2وكما موضح بالجدول رقم )في تخمين مقاومة االنضغاط للخرسانة االعتيادية ( al-hesnawi,2011 و) لخرسانة ( في تخمين مقاومة االنضغاط ل (ahmed,2013( obeed,2007الباحثين )ونتائج ، بالملحق إلى ةمعرضالو النتائج تمثل الخرسانة بنوعيها إن، حيث بالملحق (1وكما موضح بالجدول رقم )ذاتية الرص .حيث شملت النتائج فحوصات مطرقة النار هبل أوللحرارة تعرض مختلفة فتراتحرارة العالية وبالدرجات ( ultrasonic pulse velocity (( وفحص الذبذبات فوق الصوتية schmidt hammerشميدت ) تم حيث تالفي والمتمثل بمقاومة االنضغاط ، ولمديات مختلفة لمقاومة االنضغاط .إباإلضافة إلى فحص الال نموذج في إعداد ال (statistica version 8-2007استخدام البرنامج اإلحصائي الحاسوبي ) اإلحصائي للتنبأ بمقاومة االنضغاط للخرسانة . اإلحصائية نماذج التطوير -3-0 ( ، 2222 من خالل البحوث السابقة )رؤوف والسامرائي ( (al-ameeri et.al 2013(hussam ,2008 في اعتماد ) مقاومة االنضغاط يجادإلإحصائية نماذج -اإلحصائية وهي : نماذج الأسلوبين من دراسةللخرسانة فقد تم ( multiple linear regression analysisطريقة التحليل االنحداري الخطي المتعدد ) -أ يعتمد هذا األسلوب في التحليل في إيجاد عالقة بين مجموعة متعدد من المتغيرات (independent variables ) المتنبأ ( )في إيجاد المتغير ال( مطلوبdependent variable ) ( عن طريق التقريب best fitting lineحيث تم اعتماد معادلة االنحدار من خالل أفضل خط تقريب ) ، حيث تعتمد (statistica version 8-2007لمجموع المربعات بين القيم الحقيقية والقيم المتنبأ ) ( .2-0دلة )( وبموجب المعاbetaعلى قيمة المعامل ) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 206 y=a0+ a1x1+ a2x2+ a3x3+ a4x4+………………. anxn (3-1) حيث : y ( القيمة المراد التنبأ بها :dependent variable) x1،: x2 ( المتغيرات مستقلةindependent variables) a0 ثابت : a1 ،a2 : . معامل االنحدار الجزئي للمتغيرات المستقلة n عدد المتغيرات : ( non linear regression analysisطريقة التحليل االنحداري الال خطي ) -ب يعتمد هذا األسلوب في التحليل في إيجاد عالقة بين مجموعة متعدد من المتغيرات (independent variables ) ( ) المتنبأ( و المتغير المطلوبdependent variable من خالل ) والتي اعتمدت من قبل )رؤوف (exponentional equation) مركبةاقتراح معادلة أسية ( في إيجاد العالقة بين (al-hesnawi2011و al-ameeri &elt,2013) ، ) ( 2222والسامرائي (، وهي 1-0والمتمثلة بالمعادلة)في درجات الحرارة االعتيادية لالاتالفية مقاومة االنضغاط والفحوصات ا ( عن طريق التقريب best fitting lineتعتمد من خالل إيجاد االنحدار من خالل أفضل خط تقريب ) ( . statistica) بموجب البرنامج لمجموع المربعات بين القيم الحقيقية والقيم المتنبأ y=a *( x1 ) ( b) * e (x2*c) (3-2) (dependent variable: القيمة المراد التنبأ بها ) y حيث : x1 ،: x2 ( المتغيرات مستقلةindependent variables) a ،b،c. ثوابت : النتائج -2 اإلحصائي للخرسانة االعتيادية نموذج ال -2-0 أ( الخاص بالتحليل االنحداري الخطي المتعدد -2-0باستخدام األسلوب األول بالمذكور في ) -0-2-2 -على النحو األتي :و إحصائيين نموذجينفقد تم اقتراح دار االرتداد لمطرقة شميدت ( والتي تمثل )مق independent variablesاعتماد المتغيرات المستقلة ) -أ في الحصول على مقاومة الخرسانة (، سرعة الذبذبات فوق الصوتية ، درجة حرارة ومدة التعرض للحرارة إلىقد تم التوصل ( و statistica(، باستخدام البرنامج اإلحصائي) dependent variableالمتنبأ ) .(2-2-0()2-0)المعادلة 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 207 fcu=( -38.0541)+( 1.9494 )rn+ (1.9530)upv +( 0.0120 )temp+( 0.3047)t ( 4-1) fcu=( 1.030787 )rn+ (0.225502)upv +( 0.01845 )temp+( 0.307574)t ( 4-1-1) حيث : fcu: مقاومة االنضغاط للخرسانة المتنبأ temp درجة الحرارة rn: مقدار االرتداد لمطرقة شميدت t مدة التعرض upv: سرعة الذبذبات فوق الصوتية اإلحصائي وكما يلي نموذج وكانت مؤشرات ال 0.96341235 adjusted r² 0.96845892 r² 0.98410311 r 0.0005 p 191.9043 f 1.671747449 standard error of estimate ( والتي تمثل )مقدار االرتداد لمطرقة شميدت independent variablesلمستقلة )اعتماد المتغيرات ا -ب باستخدام البرنامج على مقاومة الخرسانة المتنبأ ،في الحصول (وسرعة الذبذبات فوق الصوتية فقط .(2-1-0و) (1-0اإلحصائي نفسه تم التوصل إلى المعادلة ) fcu=(-24.9823 )+( 1.95681 )rn+ (0.6361)upv ( 4-2) fcu=( 1.034688 )rn+ (-0.073446)upv ( 4-2-1) اإلحصائي وكما يلي نموذج وكانت مؤشرات ال 0.93483231 adjusted r² 0. 93611010 r² 0.96752783 r 0.0000 p 732.5964 f 2.230840119 standard error of estimate ب( الخاص بالتحليل االنحداري الالخطي -2-0باستخدام األسلوب الثاني بالمذكور في ) -4-0-4 ( والتي تمثل مقدار االرتداد لمطرقة independent variablesفان تم اعتماد المتغيرات المستقلة ) وسرعة الذبذبات فوق الصوتية فقط في الحصول على مقاومة الخرسانة المتنبأ ، باستخدام شميدت (.00( تم التوصل الى المعادلة) statisticaالبرنامج اإلحصائي) 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 208 fcu=(0.038343 ) rn ( 1.99486) e (upv*(-0.02569)) (4-3) اإلحصائي وكما يلي نموذج وكانت مؤشرات ال 0.94554962 r² 0.97239376 r اإلحصائي للخرسانة ذاتية الرص نموذج ال -2-4 أ( الخاص بالتحليل االنحداري الخطي المتعدد -2-0باستخدام األسلوب األول بالمذكور في ) -2-4-0 -النحو األتي : علىفقد تم دراسة نموذجين احصائين و ( والتي تمثل )مقدار االرتداد لمطرقة شميدت independent variablesاعتماد المتغيرات المستقلة ) -أ ، سرعة الذبذبات فوق الصوتية ، درجة حرارة ومدة التعرض للحرارة في الحصول على مقاومة .( 2-0-0و ) (0-0إلى المعادلة ) الخرسانة المتنبأ، باستخدام البرنامج اإلحصائي نفسه تم التوصل fcu=( -45.1239)+( 2.9281)rn+ (-5.6965)upv +( 0.0216)temp+( -2.3833)t ( 4-4) fcu=( 2.036620)rn+ (-0.637588)upv +( 0.170193)temp+( 0.60826)t ( 4-4-1) اإلحصائي وكما يلي نموذج ؤشرات الوكانت م 0.83284276 adjusted r² 0.85589893 r² 0.92514806 r 0.0062 p 37.12233 f 2.547549168 standard error of estimate ( والتي تمثل )مقدار االرتداد لمطرقة independent variablesاعتماد المتغيرات المستقلة ) -ب باستخدام ،وق الصوتية فقط في الحصول على مقاومة الخرسانة المتنبأ شميدت وسرعة الذبذبات ف .(2-5-0و ) (5-0(البرنامج اإلحصائي نفسه تم التوصل إلى المعادلة fcu=( -21.8944)+( 2.6849)rn+ (-9.3225)upv (4-5) fcu=( 1.86749)rn+ (-1.04344)upv (4-5-1) اإلحصائي وكما يلي نموذج وكانت مؤشرات ال 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 209 0.74971 adjusted r² 0.76697 r² 0.87577 r 0.000 p 44.432 f 3.1173 standard error of estimate ب( الخاص بالتحليل االنحداري الالخطي -2-0باستخدام األسلوب الثاني بالمذكور في ) -2-4-4 ( والتي تمثل مقدار االرتداد لمطرقة independent variablesفان تم اعتماد المتغيرات المستقلة ) ة فقط في الحصول على مقاومة الخرسانة المتنبأ ، باستخدام شميدت وسرعة الذبذبات فوق الصوتي (.0-0البرنامج اإلحصائي نفسه تم التوصل إلى المعادلة ) fcu=( 0.010315)* rn (2.60834 ) * e (upv* (-0.29045) ) (4-6 ) اإلحصائي وكما يلي نموذج وكانت مؤشرات ال 0.87626521 r² 0.76784071 r مناقشة النتائج -5 فان يجب دراسة النقطتين (،0السابقة)فقرة ال المذكورة فياإلحصائية المستنتجة نماذج مقارنة بين الاللغرض ئي يعتمد بشكل كبير على النتائج اإلحصا نموذج المهمتين إلغراض المقارنة، واحدهما هي إن اختيار ال نموذج من توافق ال نموذج اإلحصائية ،وهو الخيار المرجح اعتماده ، والثاني هو الناحية العملية في اختيار ال غيره ، أو نموذج مع المعلومات المتوفرة للحالة ، من خالل إدخال المعلومات المطلوبة في اعتماد هذا ال ( 1-0) وللخرسانة ذاتية الرص بالفقرة ( 2-0للخرسانة االعتيادية المتمثلة بالفقرة ) نماذج وهنا تبرز إن ال وكما النتائج للمؤشرات اإلحصائية تعطي انطباع إحصائي ممتاز وهذا يتجلى من خالل نماذج فإن جميع ال ؤشرات توفر الم من خالل ( 0-5)الى ( 2-5واألشكال في )( 1-5والجدول )( 2-5الجدول رقم )موضح ب values) يظهر من توزيع قيم البقايا من النتائج لمقاومة االنضغاط كما.اإلحصائية العالية residualsبشكل واضح ( للخرسانة االعتيادية وذاتية الرص على التوالي،0-5والشكل ) (2-5) ( في شكل ى أنه ال توجد أدلة على أن النماذج وهذا يدل عل .أن هذه القيم موزعة طبيعيا وتتجمع حول نقطة الصفر al-saegh , 2008) (stat soft inc. 2007) )غير كافية، أو أن هناك خطأ في التحليل العالقة بين ( للخرسانة االعتيادية وذاتية الرص على التوالي ،0-5والشكل ) (1-5)يوضح الشكل رقمكما ، أن معظم تلك النقاط تقع تقريبا نماذج خرسانة والقيم المتنبأ بها من الالقيم الحقيقية لمقاومة االنضغاط لل هي المناسبة للبيانات، وتم تحديدها بشكل صحيح نماذج هذا يدل على أن هذه ال .في خط مستقيم (.(stat soft inc. 2007) (al-saegh , 2008 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 210 ( للخرسانة االعتيادية 0-0(،)1-0ج المؤشر بالمعادلتين )ولكن تبرز هنا الناحية العملية في إتباع النموذ ( حيث إن تقييم العنصر الخرساني الذي تعرض إلى 2-0يكون أكثر ترجيحا من النموذج بالمعادلة ) الحرارة والمتمثلة مقدار الحرارة ومدة التعرض تكون في الغالب غير متوفرة في معظم تلك الحاالت للعناصر ( 5-5انية . ، كما يمكن إيجاد عالقة بين المتغيرات الثالثة حسب المخطط بالشكل )او المنشات الخرس ( ملحق بخالصة النتائج لجميع النماذج اإلحصائية الخاصة بالخرسانة 2،هذا ما موضح بالجدول ) االعتيادية . النموذج ( تكون أكثر ترجيحا من0-0(،)5-0اما الخرسانة ذاتية الرص فان النموذجين بالمعادلتين ) للسبب نفس أعاله ، كما يمكن إيجاد عالقة بين المتغيرات الثالثة حسب المخطط بالشكل (0-0بالمعادلة ) ( ملحق بخالصة النتائج لجميع النماذج اإلحصائية الخاصة بالخرسانة ذاتية الرص .1(. والجدول )5-0) االستنتاجات -6 -إلى االستنتاجات التالية :مما سبق من النتائج ومناقشتها تم التوصل إمكانية استنباط أكثر من صيغة من النماذج او المعادالت اإلحصائية ، بموجب المعلومات المتوفرة من -2 الباحثين باستعمال أكثر من فحص مجتمعا ،وباستخدام أساليب إحصائية متعدد ،بما يحقق الغرض المطلوب . لنموذج اإلحصائي للتعبير عن الصيغة او العالقة األكثر تعبيرا عن البحث في الخيار األمثل في اختيار ا -1 تلك المتغيرات وللحالة المطلوبة . اعتماد األسلوب األكثر عمليا ، حيث إن المعلومات المتوفرة يجب أن تتالئم مع طبيعة النموذج الرياضي -0 تحتوي على متغيرات كبيرة كما ،حيث في معظم األحيان ال تتوفر المعلومات المطلوبة للنماذج التي ( للخرسانة ذاتية الرص ، وعلية يفضل اختصار 0-0( للخرسانة االعتيادية ،والمعادلة )2-0بالمعادلة ) ال يكون تعبيره األحيانالنموذج إلى اقل ما يمكن من المتغيرات ، بالرغم إلى إن هذه الحالة في بعض بشكل دقيق . ائية هي عالقة وضعية تعبر عن حالة الدراسة بنسب جيدة وال تنطبق بشكل العالقة الرياضية اإلحص -0 244.% ( للخرسانة االعتيادية 0-0( ،)0-0النموذج الرياضي للعالقة اآلسية المركبة الموضح بالمعادلة ) -5 قبل قبوال ، لكون هذه الصيغة مستخدمة من أكثروالخرسانة ذاتية الرص على التوالي ، المعرضة للحرارة باحثين بشكل كبير لمثل الحاالت ، كذلك ان المؤشرات اإلحصائية لها كانت جيدة ، باإلضافة إلى ان تالفي بجهازي المطرقة والذبذبات فوق الصوتية ، وهي فحوصات إ تطبيقها يحتاج فقط الى فحص ال بسيطة تم على ضوئها استنتاج القيم الواقعية للخرسانة تلك. 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 211 تالفي للخرسانة المعرضة للحرارة ،ال إالمتوفرة من مقاومة االنضغاط والفحص الالبموجب المعلومات -0 يمكن االستفادة من النماذج السابقة للخرسانة في درجات الحرارة االعتيادية ،وذلك بسبب اختالف خواص الخرسانة ونتائج الفحوصات . ن مقاومة االنضغاط للخرسانة وسرعة بي ةالمطردجميع النماذج المستنبطة من البحث تؤكد العالقة -5 الذبذبات فوق الصوتية بشكل أساسي بالدرجة األولى ويليها باألهمية مقدار االرتداد لمطرقة شميدت . المراجع 1) ahmed s.m., (2013), ” effect of the elevated temperature on some mechanical properties of self compacting concrete reinforced by steel fiber ”, m.sc., thesis, college of engineering, university of babylon. 2) al-ameeri a.s.&ahmed s.m.,( 2013) ” improving the resistance of self compacting concrete exposed to elevated temperatures by using steel fiber ” civil and environmental research, international institute for science, technology and education (iiste) www.iiste.org, vol 3, no.13, 2013.pp30-50. 3) al-ameeri a. s. & alhussain k.a. & essa m.,( 2013) ” constructing a mathematical models to predict compressive strength of concrete from non-destructive testing” international journal of civil engineering and technology (ijciet) ,volume 4, issue 4, julyaugust (2013), pp. 01-20. 4) al-hesnawi k..a., (2011), ” constructing a mathematical models to predict some properties of concrete from non-destructive testing”, m.sc., thesis, college of engineering, university of babylon. 5) al-saegh,m.s , (2008),” a statistical model for predicting auto-clave expansion of portland cement” qaddissia journal for engineering ,vol.1 no. 2,2008, pp.196-210. 6) efnarc, (2005), ”the european guidelines for self-compacting concrete specification, production and use”. the european federation of specialist construction chemicals and concrete systems. 7) helal m.a, and heiza kh.m., (2011), ”effect of fire and high temperature on the properties of self compacted concrete”, housing & building national research center, cairo, egypt. 8) hussam a.,(2008) “non-destructive tests for self-compacting concrete with compressive strength in range (20-80)mpa” m.sc. thesis, college of engineering ,university of almustansiriya . 9) iaea:(2002) international atomic energy agency, “guidebook on non-destructive testing of concrete structures”, vienna, pp.1-2. 10) karim m.m., (2005), ”investigation of the behavior and properties of reinforced concrete slabs exposed t o fire flame”, m.sc., thesis, college of engineering, college of engineering, university of babylon. 11) lankard, d. r., birkimer, d. l., fondriest, f. f., and snyder, m. j., "effect of moisture content on the structural properties of portland cement concrete exposed to temperatures up to 500f", aci special publication, sp-25, temperature and concrete, detroit, michigan, usa, 1971, pp. 59-105. http://www.iiste.org/ 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 212 12) neville a.m., (1995), ”properties of concrete”,4th and final edition, longman group ltd, london. 13) nikolai, g. z., "thermal properties of concrete under sustained elevated temperatures", aci special publication, sp-25, temperature and concrete, detroit, michigan, usa, 1971, pp. 131. 14) obeed a.t., (2007), ”effect of exposure to fire flame on some mechanical properties of selfcompacting concrete using different types of filler”, m.sc., thesis, college of engineering, university of babylon. 15) stat soft inc. 2007 ”statistica version 8-2007” www. statsoft.com. 16) umran m.k., (2002), ” fire flame exposure effect on some mechanical properties of concrete ”, m.sc., thesis, college of engineering, university of babylon. 255, جامعة الشارقة, ص ) 2لطبعة اللخرسانة" االتالفية("الفحوص غير 2222السامرائي مفيد، رؤوف زين العابدين ) (25 -225 .) المالحق ( يمثل النتائج الخرسانة االعتيادية المعتمدة بالبحث مع نتائج مقاومة االنضغاط المستحصلة من 2الجدول ) ( .0-0(،)1-0(،)2-0النماذج االحصائية بالمعادالت ) ص المعتمدة بالبحث مع نتائج مقاومة االنضغاط المستحصلة ( تمثل نتائج الخرسانة ذاتية الر 1اما الجدول ) ( .0-0(،)5-0(،)0-0من النماذج االحصائية بالمعادالت ) ( خالصة المؤشرات اإلحصائية للنماذج للخرسانة االعتيادية المتعرضة الى الحرارة العالية2-5جدول ) او نموذج ال المعادلة rالمعامل rالمعامل 2 في التخمين الخطأ القياسي standard error of estimate مقدار التفاوت بين القيم * لصييةاالالقيم المخمنة و % 19.5الى -19.8 1.671747449 0.96845892 0.98410311 (1-4معادلة ) 19.8الى -19.1 2.230840119 0.93611010 0.96752783 (2-4معادلة ) 18الى 170.94554962 0.97239376 (3-4معادلة ) % 111* قيمة الفرق مقسمة عيى القيم األلصيية مضروبة في 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 213 المتعرضة الى الحرارة العالية ذاتية الرص ( خالصة المؤشرات اإلحصائية للنماذج للخرسانة 1-0جدول ) او نموذج ال المعادلة rالمعامل rالمعامل 2 الخطأ القياسي في التخمين standard error of estimate مقدار التفاوت بين القيم * الحقيقةالقيم المخمنة و % 17.5الى -14.2 2.547549168 0.85589893 0.92514806 (4-4معادلة ) 22.2الى -18.7 3.117335176 0.76696947 0.87576793 (5-4معادلة ) 22الى 220.76784079 0.87626525 (6-4معادلة ) % 111األلصيية مضروبة في * قيمة الفرق مقسمة عيى القيم karim,2005))، (umran ,2002 ) حسب ( تفالصيل نتائج الفحولصات ليخرسانة االعتيادية 1جدول ) مع نتائج التنبؤ حسب النماذج اإلحصائية al-hesnawi,2011 و) مقدار ت االرتداد (rn) سرعة الذبذبة (upv) (km/sec) زمن التعرض (hour) درجة الحرارة (cᵒ) مقاومة االنضغاط الحقيقية (mpa) مقاومة االنضغاط حسب النموذج بالمعادلة (mpa) eq(1-3) eq(1-3) eq(1-3) 1. 31 4.45 0.5 25 30.5 31.52 32.85 32.29 2. 35 4.64 0.5 25 41.3 39.69 40.55 40.94 3. 35 4.64 1 25 41.3 39.84 40.55 40.94 4. 35 4.64 1.5 25 41.3 39.99 40.55 40.94 5. 35 4.64 2 25 41.3 40.15 40.55 40.94 6. 32 4.4 1 25 30.8 33.52 34.84 34.45 7. 33 4.45 1 25 30.6 34.60 35.78 35.48 8. 35 4.7 1 25 38.4 39.96 40.52 40.87 9. 35 4.9 1 25 38.6 40.74 40.78 41.13 10. 32 4.48 0.5 25 34.1 33.53 34.79 34.38 11. 36 4.66 0.5 25 45.2 41.68 42.50 43.28 12. 36 4.66 1 25 45.2 41.83 42.50 43.28 13. 36 4.66 1.5 25 45.2 41.98 42.50 43.28 14. 36 4.66 2 25 45.2 42.13 42.50 43.28 15. 34 4.49 0.5 25 37.3 37.45 38.69 38.79 16. 38 4.67 0.5 25 48.2 45.60 46.41 48.20 17. 38 4.67 1 25 48.2 45.75 46.41 48.20 18. 38 4.67 1.5 25 48.2 45.90 46.41 48.20 19. 38 4.67 2 25 48.2 46.05 46.41 48.20 20. 26 3.25 0.5 400 22.6 23.92 23.83 23.45 21. 27 3.34 1 400 22.6 26.20 25.73 25.22 22. 27 3.16 1.5 400 21.7 26.00 25.84 25.34 23. 26 3.25 2 400 22.9 24.38 23.83 23.45 24. 30 3.25 0.5 400 28.9 31.72 31.65 31.19 25. 31 3.57 1 400 32.2 33.47 32.43 31.98 26. 29 3.34 1.5 400 31 31.03 30.42 29.89 27. 29 3.39 2 400 31.4 30.50 29.61 29.05 28. 28 3.3 1 400 25.8 27.68 27.32 26.76 29. 28 3.45 1 400 26.1 28.95 28.20 27.63 30. 31 3.5 1 400 31.9 33.72 32.86 32.45 31. 30 3.7 1 400 31.3 33.33 31.95 31.45 32. 30 4 0.5 400 37 33.18 31.18 30.60 33. 27 3.31 1 400 25.9 26.14 25.75 25.24 34. 28 3.27 1.5 400 27.3 28.16 27.73 27.17 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 214 35. 27 3.18 2 400 26.3 25.41 25.05 24.58 36. 32 3.73 0.5 400 36.6 36.55 35.26 35.05 37. 31 3.63 1 400 35.2 34.56 33.37 32.98 38. 31 3.35 1.5 400 34.3 34.75 34.13 33.86 39. 30 3.49 2 400 35.7 33.03 31.89 31.42 40. 30 3.49 0.5 400 31 32.19 31.50 31.00 41. 31 3.41 1 400 29.9 33.35 32.73 32.32 42. 31 3.37 1.5 400 29.1 33.43 32.75 32.35 43. 29 3.28 2 400 29.5 30.28 29.68 29.13 44. 35 3.83 0.5 400 41.5 41.62 40.09 40.62 45. 33 3.64 1 400 39.1 39.26 38.06 38.26 46. 32 3.55 1.5 400 37.6 36.51 35.38 35.21 47. 32 3.6 2 400 36.6 37.34 35.93 35.82 48. 25 2.23 0.5 500 20.4 21.18 22.52 22.26 49. 24 2.27 1 500 19.2 19.46 20.54 20.50 50. 25 2 1.5 500 18.3 21.81 23.45 23.11 51. 23 1.83 2 500 18 16.17 18.08 18.39 52. 28 2.78 0.5 500 28.5 28.10 28.04 27.51 53. 29 2.6 1 500 26.9 29.26 29.52 29.04 54. 28 2.37 1.5 500 26 27.60 28.30 27.81 55. 27 2.73 2 500 25.2 26.51 26.11 25.62 56. 26 2.5 1 500 22.8 23.02 23.52 23.18 57. 27 2.58 1 500 22.4 25.91 26.21 25.72 58. 28 2.77 1 500 27.6 29.01 28.83 28.31 59. 28 2.75 1 500 26.5 27.80 27.67 27.14 60. 27 2.32 0.5 500 24.2 25.25 26.38 25.89 61. 25 2.24 1 500 22.5 21.35 22.51 22.25 62. 26 2.1 1.5 500 21.2 22.40 23.78 23.42 63. 24 1.92 2 500 20.5 19.08 20.76 20.68 64. 29 2.9 0.5 500 33.4 30.28 29.92 29.42 65. 30 2.66 1 500 31.6 31.91 32.03 31.67 66. 30 2.52 1.5 500 29.4 30.82 31.14 30.74 67. 28 2.61 2 500 28 29.00 28.93 28.43 68. 27 2.43 0.5 500 28 25.46 26.31 25.82 69. 28 2.38 1 500 25.7 26.49 27.32 26.82 70. 28 2.2 1.5 500 23.9 27.27 28.41 27.93 71. 26 2.07 2 500 22.8 23.27 24.58 24.17 72. 32 2.94 0.5 500 37.6 35.23 34.79 34.66 73. 32 2.8 1 500 36.2 36.09 35.85 35.89 74. 32 2.62 1.5 500 33.7 34.91 34.99 34.94 75. 31 2.66 2 500 30.9 34.17 33.99 33.81 76. 24 2.33 1 600 19.1 20.19 19.91 19.96 77. 24 2.31 1 600 19.6 21.51 21.29 21.16 78. 26 2.4 1 600 23 23.83 23.39 23.06 79. 25 2.42 1 600 22.4 22.90 22.40 22.15 80. 20 1.83 0.5 700 16.2 13.04 12.99 14.41 81. 21 1.74 1 700 14.3 15.75 15.79 16.53 82. 20 1.56 1.5 700 13.8 12.43 12.77 14.22 83. 19 1.47 2 700 13.1 10.85 11.26 13.13 84. 25 2.09 0.5 700 24 22.32 21.63 21.46 85. 24 1.91 1 700 20.7 20.76 20.37 20.35 86. 22 1.76 1.5 700 19 17.11 16.95 17.46 87. 21 1.48 2 700 17.8 14.76 15.17 16.03 88. 21 1.92 0.5 700 18.8 15.95 15.67 16.45 89. 23 1.7 1 700 17.4 18.20 18.36 18.61 90. 21 1.52 1.5 700 16.4 15.47 15.93 16.62 91. 21 1.57 2 700 16.4 14.94 15.11 15.99 92. 25 2.28 0.5 700 27.1 23.67 22.49 22.23 93. 26 2.1 1 700 23.9 25.42 24.56 24.15 94. 23 1.86 1.5 700 22.6 20.03 19.62 19.69 95. 23 1.58 2 700 19.9 18.27 18.43 18.67 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 215 96. 24 2.07 0.5 700 22.4 20.92 20.27 20.26 97. 23 1.84 1 700 21.2 19.06 18.85 19.04 98. 24 1.71 1.5 700 18.7 19.93 19.91 19.94 99. 23 1.62 2 700 17.9 17.96 18.01 18.32 100. 28 2.38 0.5 700 29.9 29.13 27.71 27.21 101. 27 2.01 1 700 27.5 26.41 25.79 25.33 102. 26 2.15 1.5 700 25.1 25.67 24.53 24.12 103. 23 1.64 2 700 23.1 18.98 18.98 19.14 (obeed 2007حسب المصدرين ) ذاتية الرص( تفالصيل نتائج الفحولصات ليخرسانة 2جدول ) ahmed,2013) )مع نتائج التنبؤ حسب النماذج اإلحصائية مقدار ت االرتداد (rn) لذبذبة سرعة ا (upv) (km/sec) زمن التعرض (hour) درجة الحرارة (cᵒ) مقاومة االنضغاط الحقيقية (mpa) مقاومة االنضغاط حسب النموذج بالمعادلة (mpa) eq(4-3) eq(5-3) eq(6-3) 1 39 4.42 2 25 42 39.67 41.61 40.36 2 35 4 0.5 25 35 33.92 34.79 34.38 3 36 4.25 1 25 33 34.23 35.14 34.41 4 33 3.5 0.5 300 35.6 36.85 34.08 34.10 5 31 3.3 1 300 33.8 31.53 31.11 31.22 6 30 3.2 1.5 300 25.2 27.39 28.82 29.02 7 31 3.35 0.5 300 32.2 30.39 28.76 29.00 8 29 3.2 1 300 28.5 24.19 24.79 25.38 9 28 3 1.5 300 22.5 22.68 25.32 25.69 10 32 3.5 0.5 300 29 32.46 30.05 30.20 11 30 3.35 1 300 25.5 27.73 27.42 27.78 12 29 3.25 1.5 300 20.5 22.72 24.33 25.02 13 28 2.75 0.5 450 32 29.73 27.65 27.62 14 28 2.6 1 450 28.5 28.22 27.97 27.79 15 27 2.3 1.5 450 24.8 26.39 28.62 28.08 16 27 2.65 0.5 450 29.8 27.37 25.89 25.86 17 27 2.35 1 450 25.5 26.42 27.35 26.87 18 24 2.15 1.5 450 20.5 19.05 22.50 21.99 19 28 2.8 0.5 450 24.5 27.98 25.84 25.97 20 26 2.55 1 450 21 23.82 24.14 24.13 21 24 2.3 1.5 450 18.5 18.19 21.10 21.06 22 25 2.35 0.5 600 28.5 26.46 23.32 23.08 23 24 2.25 1 600 26 21.45 20.23 20.22 24 22 1.88 1.5 600 20 17.97 19.65 18.96 25 24 2.25 0.5 600 24 24.10 21.57 21.36 26 24 2.15 1 600 24 22.89 21.96 21.52 27 22 1.95 1.5 600 18.5 17.57 18.99 18.58 28 24 2.1 0.5 600 20.6 23.49 21.62 21.12 29 23 2.2 1 600 19.8 19.68 18.81 18.96 30 23 2 1.5 600 14 18.75 19.87 19.41 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 216 نماذج ( المستحصية من residualقيم مقاومة االنضغاط المتبقية ) :(1-5الشكل ) الخرسانة االعتيادية expected normal distribution of standard residualsvalues of compressive strength obtained by eq(4-1) -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 0 2 4 6 8 10 12 14 16 18 20 22 24 26 n o o f o b s e rv a ti o n s expected normal distribution of standard residuals values of compressive strength obtained by eq(4-2) -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0 2 4 6 8 10 12 14 16 18 20 22 24 n o o f o b se r v a ti o n s frequency distribution: -8 -6 -4 -2 0 2 4 6 8 residual compressive strength obtained by eq (4-3) 0 5 10 15 20 25 30 35 40 n o o f o b s e r v a ti o n 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 217 الحقيقية والمتنبأ بها ليمقاومة االنضغاط المستحصية من (العالقة بين القيم2-5الشكل ) ةالخرسانة االعتيادي نماذج predicted vs. observed values obtained by eq (4-1) 5 10 15 20 25 30 35 40 45 50 predicted compressive strength 10 15 20 25 30 35 40 45 50 o b s e r v e d c o m p r e s s iv e s tr e n g th 95% confidence predicted vs. observed values obtained by eq(4-2) 5 10 15 20 25 30 35 40 45 50 predicted compressive strength 10 15 20 25 30 35 40 45 50 o b s e r v e d c o m p r e s s iv e s tr e n g th 95% confidence predicted vs. observed values obtained by eq(4-2) 5 10 15 20 25 30 35 40 45 50 predicted compressive strength 10 15 20 25 30 35 40 45 50 o b s e r v e d c o m p r e s s iv e s tr e n g th 95% confidence 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 218 نماذج ( المستحصية من residual( قيم مقاومة االنضغاط المتبقية )3-5الشكل ) الخرسانة ذاتية الرص distribution of standard residuals of compressive strength of obtained by eq(4-4) -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 0 1 2 3 4 5 6 7 8 9 n o o f o b s e r v a ti o n distribution of standard residuals of compressive strength obtained by eq (4-5) -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 0 1 2 3 4 5 6 7 8 n o o f o b s e r v a ti o n s -8 -6 -4 -2 0 2 4 6 8 residual values of compressive strength obtained by (4-6) 0 1 2 3 4 5 6 7 8 n o o f o b s e r v a ti o n s 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 219 النضغاط المستحصية من (العالقة بين القيم الحقيقية والمتنبأ بها ليمقاومة ا4-5الشكل ) الخرسانة ذاتية الرص نموذج predicted vs. observed values (compressive strength ) obtained by eq(4-4) 16 18 20 22 24 26 28 30 32 34 36 38 40 42 predicted compressive strength 10 15 20 25 30 35 40 45 o b s e r v e d c o m p r e s s iv e s tr e n g th 95% confidence predicted vs. observed values obtained by eq (4-5) 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 predicted compressive strength 10 15 20 25 30 35 40 45 o b s e r v e d c o m p r e s s iv e s tr e n g th 95% confidence observed versus predicted values obtained by eq (4-6) 15 20 25 30 35 40 45 predicted compressive strength 10 15 20 25 30 35 40 45 o b s e r v e d c o m p r e s s iv e s tr e n g th 4102 4العدد 7مجلة القادسية للعلوم الهندسية المجلد 220 ( و مقدار االرتداد وسرعة الذبذبات فوق الصوتية fcu( العالقة بين مقاومة االنضغاط ليخرسانة االعتيادية)5-5الشكل ) (rn&upv( المستنتجة من المعادلة )3-4) model: fcu=a*(rn^b)*(exp(upv*c)) fcu=(.010315)*(rn^(2.60834))*(exp(upv*(-.29045))) 1 3 2 4 107 11 5 68 12 9 13 191416 20 151722 21 2325 18 26 2829 302724 1 3 2 4 1057 11 68 12 9 13 191416 15172022 21 2325 18 26 2829 302724 ( و مقدار االرتداد وسرعة الذبذبات فوق الصوتية fcuين مقاومة االنضغاط ليخرسانة ذاتية الرص)( العالقة ب6-5الشكل ) (rn&upv( المستنتجة من المعادلة )6-4) model: fcu=a*(rn^b)*(exp(upv*c)) fcu=(.038343)*(rn^(1.99486))*(exp(upv*(-.02569))) 9 16171819 11121314 2345 8 15 67 10 1 32 44 45 36 37 31 4647 2530 39 40414227 29 38 24 26 43 2834 21 22 3335 2023 72 64 73 7565 5258 59 55 74 53 66 67 57 68 56 5469 70 100 60 48 61 7879 92 497776 101 50 62 7193 102 84 96 63859497 5186 81 88 80 8995 98 103 99 879091 82 83 16171819 11121314 9 2345 8 4415 45 67 10 364647 73 1 37 38 72 75 74 32 312530 39 404142 24 65 2726 43 64 53 66 29 2834 5258 5967 5469 70 10021 22 3335 55 57 68 60101 2023 56 48 61 7879 92 50 62 7193 102 4977 84 96 6385 76 94 97 8995 98 103 5186 99 81 88 87909180 82 83 template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 536 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. evaluation of the effect of length on the performance of rectangular to rectangular waveguide taper hasan f. khazaal, wasit university, college of engeneering, electrical engineering, iraq. e-mail: hf1964@yahoo.com haider th. salim alrikabi, wasit university, college of engeneering, electrical engineering, iraq. e-mail: haiderelectrical@gmail.com mansour s. farhan, wasit university, college of engeneering, electrical engeneering, iraq. e-mail: mansur545@yahoo.com received on 14 september 2017 accepted on 31 october 2017 published on 20 february 2018 doi: 10.30772/qjes.v10i4.503 abstract: rf waveguide taper have a significant role in radar or communication systems through the use of it for joining two waveguides that have different cross sections, and this difference may be in dimensions of cross section or in the shape of it. the tapering may be from rectangular to rectangular waveguide (i.e. each waveguide operating at a certain frequency), or transition from rectangular to circular or elliptical waveguide. in this paper; two rectangular to rectangular waveguide tapers have been fabricated to join waveguide operating at c band frequencies with another one operating at x band frequencies. the fabricated tapers have the same shape but differ in length (8 cm, and 16 cm) in order to measure the effect of length on the most important parameters that have an effect on the performance of the taper, like voltage standing wave ratio "vswr", return losses, and input resistance. many tests have been done using two port network analyzer. the results of the tests indicate that there is no effect on the performance of the waveguide taper although there is an extra 8 cm in length. keywords: waveguide, radio frequency, vswr, return losses, input resistance. introduction this rf waveguide transition or tapers are used to connect waveguide components with different cross sectional sizes and shapes. there are many kinds of waveguide tapers, like rectangular-to-rectangular of radio frequency waveguide transition adapters which designed to connect one rectangular waveguide to mailto:hf1964@yahoo.com mailto:haiderelectrical@gmail.com mailto:mansur545@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 537 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. another rectangular waveguide but in different cross section size. similarly, circular-to-circular adapters are used to connect one circular waveguide to another circular waveguide. circular-to-rectangular waveguides that change a circular waveguide section to rectangular waveguide section [1]. in a tapered section, the dimensions of waveguide vary smoothly and for this reason there are possibilities of providing a transition from one impedance level to another [2]. rectangular to circular waveguide taper rectangular to rectangular waveguide taper figure 1: shows the types of waveguide taper and transition. the aim of the research is to compare the performance of two waveguide tapers differ in length but have the same rectangular cross section of both corresponding ends. these tapers must be used to connect between waveguide operating at c–band frequencies into waveguide operating at x-band frequencies. the comparison here covering the most significant parameters; voltage standing wave ratio, return losses, and input resistance, and impedance. the paper is arranged as follows; introduction, background, practical work and testing, results, discussion, and conclusions. 1. background article rectangular to rectangular waveguide tapers used to make transition between two different waveguide cross sections in order to mitigate some technical problems in connection and / or to reduce the cost of using new waveguides in a whole system. the taper behaves like frequency transformer because the two connected waveguides operating at different frequency bands. figure 2 show the types of rectangular to rectangular waveguide tapers with different flanges. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 538 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: types of rectangular to rectangular waveguide tapers [3]. in order to satisfy the aim of this work, the fabrication of two rectangular to rectangular waveguide tapers have been done. these tapers have difference in length but have the same cross section dimensions for corresponding ends, in order to check the effect of length on the most common characteristic, voltage standing wave ratio "vswr", return losses, and input resistance. the fabricated waveguide tapers are subjected to the following boundaries: vswr of the tapers ≤ 2. high return losses as possible. input resistance near 50 ohm. voltage standing wave proportion (vswr) is a unit-less proportion extending from one to limitlessness. it communicates the measure of reflected vitality at the information or yield of the gadget. an estimation of one demonstrates that the majority of the vitality will go through, while some other esteem shows that a bit of the vitality will be reflected. in media communications, return misfortune is the loss of influence in the signal returned/reflected by an irregularity in a transmission line or optical fiber. this intermittence can be mismatched with the ending load or with a device embedded in the line. it is typically communicated as a proportion in decibels (db) [4,5]. where rl(db) is the return loss in db, pi is the incident power and pr is the reflected power. reflection coefficient (γ) can be calculated as; sl sl i r zz zz v v γ    2.2 where r v , i v are the reflected and incident voltage respectively. and are the load and source impedance respectively. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 539 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. return losses is related with reflection coefficient as shown in equation (2.3). ||log20)( 10 dbrl 2.3 return loss has a relation to “both standing wave proportion (swr) and reflection coefficient (γ). expanding return loss relates to bring down swr. return loss is a measure of how well gadgets or lines are coordinated. a match is great if the arrival misfortune is high. an exceptional yield misfortune is alluring and brings about a lower inclusion misfortune. return loss is utilized as a part of present day practice in inclination to vswr in light of the fact that it has better determination for little estimations of reflected wave. properly, misfortune amounts, when expressed in decibels, ought to be certain numbers. in any case, return loss has generally been communicated as a negative number, and this tradition is still broadly found in the writing. the right meaning of return misfortune is the distinction in db between the occurrence influence sent towards the device under test (dut) and the influence reflected, bringing about a positive sign”: be that as it may, taking the proportion of reflected to episode control brings about a negative sign for return loss; i r 10 p p 10log(db)lr  2.4 where rl'(db) is the negative of rl(db). return loss with a positive sign is indistinguishable to the greatness of γ when expressed in decibels yet of inverse sign. that is, “return misfortune with a negative sign is all the more legitimately called reflection coefficient. the s-parameter s11 from two-port system hypothesis is every now and again likewise called return misfortune, yet is really equivalent to γ”. caution is required while talking about expanding or diminishing return loss since these terms entirely have the inverse importance when return misfortune is characterized as a negative amount. for this presented work it would be to get the value of vswr and return losses according to the international standards. 2. fabrication and testing of waveguide tapers 2.1. fabrication of waveguide taper the practical work has been done by fabricating two of rectangular to rectangular waveguide tapers. the fabricated tapers were made from aluminum sheet metals having thickness of 3 mm. the sheet metal is processed by milling to the shapes and dimensions indicating in figures (3-7) , to prepare taper's walls and the connections flanges. the shaped walls and flanges are assembled together to make the final products as shown in figures (8-9). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 540 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 28 m m 41 m m 80 mm figure 3: eplane side wall of short taper. 10 m m 20 m m 80 mm figure 4: h plane side wall of short taper. 41 m m 28 m m 160 mm figure 5: eplane side wall of long taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 541 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 6: h plane side wall of long taper. c-band connection flange x-band connection flange figure 7: connection flanges. figure 8: assembled short waveguide taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 542 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 9: assembled long waveguide taper. 2.2. testing the fabricated tapers subjected to (s) and (z) parameters tests to point out the values of reflection losses, input resistance and impedance, and vswr of each taper, in order to compare the performance of them. the tests done by using two port network analyzer as shown in figure (10) . 2.3. authors figure 10: waveguide taper test setup using two port network analyzer. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 543 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2.3. results the results of tests are shown in figures (11-16), covering vswr, return losses, and input resistance of each taper. from the figures of tests, it can be seen that the values of the pre mentioned parameters satisfying the standards values. also the results show that there is no significant difference in the performance of the two tapers, although that the difference in length between them reaching an 8 cm as an extra length (i.e. there is smooth transition in cross section between the two ends of the long taper). table 1 summarizes the results of the two tapers. table 1: results of the tests of two waveguide tapers. taper no. vswr return losses input resistance 1 (80 mm) 1.01 -46.1795 db 49.69  2 (160 mm) 1.011 -43.6314 db 49.44  figure 11: vswr results of the short waveguide taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 544 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 12: reflection loss results of the short waveguide taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 545 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 13: z-parameter or input resistance result of the short waveguide taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 546 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 14: vswr results of the long waveguide taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 547 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 15: reflection loss results of the long waveguide taper. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 548 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 16: z-parameter or input resistance result of the long waveguide taper. conclusions from the results it can be conclude that the change of length of waveguide taper has no effect on the results and the performance of the long taper although that it has small flaring angle compare to the short one, so it can be use the tapers with any length according to the need of application. biodata hasan fahad kazaal is assistant professor at electrical engineering department, wasit university. haider alrikabi is a lecturer at electrical engineering department, wasit university. mansour s. farhan is assistant professor at electrical engineering department, wasit university. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 549 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. references 1. kamo b., cakaj s., koliçi v., mulla e., " simulation and measurements of vswr for microwavecommunication systems", int. j. communications, network and system sciences, issue 5, pp. 767-773, 2012. 2. pasquali microwave systems company catalogue, http://www.pasquali-microwavesystems.com/. 3. srb instruments company catalogue, http://azarel.com.sg/product/srb-catalogue/. 4. trevor s. bird, "definition and misuse of return loss", ieee antennas & propagation magazine, vol.51,issue.2, pp.166-167, april 2009. 5. marcuvitz n., "waveguide handbook", peter peregrinus ltd, 1986 edition. http://www.pasquali-microwavesystems.com/ http://azarel.com.sg/product/srb-catalogue/ ٢٠٠٩ ٢ ا� �د ٢ ا����� ���� ا���د��� �� ��م ا������� ١٠٠ ������ ��� � �� ����� ������ � �� ��� ���� � ����� �� �� ���� ���� ������ � ���� ������� ���� ������ �� ��! �������� �"��#/������� ���% ������� ������� &�� �!'���: ������ � ��� ��� � �� ����� �� � �� ����� ����� � � � ������ ����� �� � !�" � �"#�� � �$%&���� '�(� ����� ����� �� )�$�� ���* +������� ������ '�(� ����� �� � ���� ���$� �� + ���� ��� �� ���, ���%�� ��.��� ��%�� �� ��.%��� )�$ ���* �� /�* 0��� � �� ��.%��� )�$ 1 � �2��#� 1 3� �(�� � �� � �� ����� 1��� ����� ��4 �� )�$ 5 ����� ��� ����� '�( � �� ���* � ��� ��� 1��*� 6�&7��� ������ ���4" +8 '�( 1� /�*9�.�� �: /*��� 1 ���& 1��&*� ���&� (���# �;� ����;� �8� ��8�7, ��� �8�7<� �� ������ !�" ����=�� >���<� � , � ���. �� ����� � �� ��� 1�� @a����� �b�8� �� 1�& �& � ���& �" ����=��� >�%�c� )�$ 5 5��� 1��&*�� ������ 5����� ��� �� �8�7, �� �=��� � � �� 1 �: �" 6�=� +��� � *�� �8� 1$ � +������� d� � ��� ��� . � ��� � *� +8 � � �� ���� �� ��*�� 1, ��e '�($ �� �=&��#� 5�&��� 1& �� d�����# ������� ��� ��� � �%��. ���� ����%�� : ���f��� 1 b 0 ��.%��� )�$ 0 � ��� 0 ����� � ��0� ��� ��� ) estimstion of time value of wasted time roads due to deteriorstion of level of service (los)and proposed suggestions to improve it sada a. alyasri college of engineering al-qadisiya university ٢٠٠٩ ٢ ا� �د ٢ ا����� ���� ا���د��� �� ��م ا������� ١٠١ abstract: a new approach to calculate the delay time on roads due to the deterioration of the level of service (los) was adopted. the approach bases on the daily traffic volume and road volume capacity. the time value was accordingly estimated based on direct and indirect costs and then compared to the cost of the los improvement. the results of comparison were demonstrated through figures and tables the purpose of this research was to provide decision maker with necessary and optimum way decide on whether maintanence or road exteusion is proper solution when los is deteriorated the comparison has shown that time value curves intersect cost of construction a maintanence at los then we shall know the boundary to improve. los by construction new line, upgrading low los roads depends on both the daily traffic volume and the present los of the road. ���� ���� * ����nomenclature td ��$� �� +�$�� ���f��� 1 b tp���� �� ��*�� ������ ���8 ��� )time period(0) 1hour( lt ������ ���8 ��� )length of time interval(0) 15 min( ic ������ ���8 � � )interval capasity(0) vehicles/15hr( d ��*�� ������ ���8 ��� �4� ���� ��)demand(0)vehicles( cd ������ ���8 �4� 5 �� �� �������� " )cumulative demand (0)vehicles( vd )��=��� 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���� ا���د��� �� ��م ا������� ١١٧ ���!���references 1national research council, 2000," highway capacity manual",washington, d.c. 2 ^ ���� � * 0mnno 0 "��� , ��e� ����� ��� �� +8 ����� ����=� " 0q����$ �*����� ���� ������$���� 0���.��>�%�c� � >����� �� �: 3safar majed. m. yousif 1999 " optimal managerial solution for estimating construction costs of highway projects in iraq, civil eng. 4lin, leekue,1995 " improving the productivity of roadway construction job sites with a portable expewt system", ph.d. thesis, the university of utah, civil eng. dep. 5cliff j. schexnayder, ph.d.p.e. eminent sholar, sandra l.weber, ph.d.p.e. associate professor, christine fiori, ph.d.p.e. assistant professor, arizona stste university, jun 2003 " project cost estimating a synthesis of highway practice" 6r.l. peurifoy , 1970, " construction planning equipment, and methods" , part1, 2 ed ed. megaw-hsill book co-.-new york. 7r.l. peurifoy , 1970, " construction planning equipment, and method" part 2 , 2 ed 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faaa `n.c daaa ff.c caaa pn.o maaaa of.o m`aaa cn.d mfaaa maf.d 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 ا����� ��� ����ى ا� ��� (l.o.s) ( آ�\���� ) (� ا� �� ر �� د� ر �� �� ) � �� � �� وا � ا" �# ا� s#ر tuv)١ (*��wا��7وري ا� s�wت ا��5yz���u9ا]� وا�� ا� `#� -�\ ا�9c� _c$ �>7c�ى ا�[��� و-�\ ا� دا�� ا� �ا]� z�uدا�� ا� max z�u � ا�دا� min d e f ab c ٢٠٠٩ ٢ ا� �د ٢ ا����� ���� ا���د��� �� ��م ا������� ١٢٢ 0 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 0 2 4 6 8 10 12 14 16 18 20 22 24 �#�ل ا�()� ا�'�ورى ا����� (��آ&� \��م)* 1000 ( + ا� �� ر �� د� ر �� �� ) � �� � �� وا � �ا" #� ا s#ر tuv)٢ (����w7<� ا�cت ا��5yz��u9ا]� وا�� �ل ا�s�w ا��7وري ا����a و-�\ ا�� \��#` ا� al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 135 design and implementation of wireless voice controlled mobile robot dr. ali ahmed abed college of engineeringuniversity of basrah aaad_bah@yahoo.com dr. abbas a. jasim college of engineeringuniversity of basrah abbas.a.jasim@ieee.org received 26 august 2015 accepted 21 january 2016 abstract this paper presents a technique for a speech recognizer used to control the motion of an intelligent automated mobile robot. the aim is to interact with the mobile robot using natural and direct communication techniques. the voice is processed to get proper and safe movement of a mobile robot and satisfying high recognition rate. features are extracted from speech signal using mel frequency cepstral coefficients (mfcc). to realize feature matching, an efficient dynamic time warping (dtw)-based speech recognition system is presented which is applicable for isolated words of arabic language. the tested words are compared to a trained database using this dtw algorithm. on the other side, the mobile robot is designed with two servo motors as driving actuators. these actuators are controlled by l298 motor driver circuit. the control algorithm is programmed and downloaded into a pic18f45k22 microcontroller which is interfaced to a usb port of a 10" notebook computer. the robot proves a capability of understanding the full meaning of the five arabic speech commands that steer it forward, backward, right, left, or stop. keywords: arabic speech recognizer, mel frequency cepstral coefficients, dynamic time warping, pattern recognition , mobile robot. تصميم وتنفيذ روبوت متحرك السلكي مسيطر عليه بالصوت علي احمد عبدد. جامعة البصرة-كلية الهندسة عباس عبد االمير جاسمد. جامعة البصرة-كلية الهندسة الخالصة البحث طريقة لبناء مميز كالم يستخدم للسيطرة على حركة روبوت متحرك آلي وذكي يستطيع التفاعل وفهم لغة الكالم الطبيعية يقدم آمنة بصورة مباشرة. يقدم البحث الخطوات التفصيلية الالزمة لمعالجة االشارة الصوتية بما يضمن نسبة تمييز عالية تؤدي الى حركة تستخدم dtwوخوارزمية معتمدة على mfccوطبيعية للروبوت. الخوارزميات المستخدمة للمعالجة الصوتية هي: خوارزمية دة لتمييز الكلمات العربية المنفصلة. تعتمد عملية التمييز على مقارنة الكلمات االختبارية مع الكلمات المدربة مسبقاً والمخزونة في قاع وذلك l298تساق بواسطة مسيطر نوع servoجانب آخر، فقد تم بناء روبوت متحرك ثنائي المحركات من نوع بيانات مسبقة. من لتحقيق خوارزمية السيطرة الصوتية. تمت موائمة الروبوت مع مميز الكالم من خالل معالج )مايكروكونترولر( نوع mailto:aaad_bah@yahoo.com mailto:abbas.a.jasim@ieee.org al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 136 pic18f45k22 ًبأكملها من خالل توجيه الروبوت تم اختبار المنظومة كدائرة بينية صممت بشكل كامل لهذا الغرض. واخيرا .على المسار المطلوبوجيه الروبوت باستخدام خمس كلمات عربية هي: امام، خلف، يمين، يسار، قف والتي بواسطتها يمكن ت روبوت المتحرك، الاالنماط مميز كالم عربي، معامالت تردد ميل، معامالت الوقت الديناميكي، تمييزالكلمات المفتاحية: nomenclature ann dist(x,y) dtw f fft f mel gd hmm k l ld lpc m mfcc rr v x y artificial neuralnetwork euclidean distance between two points dynamic time warping tone frequency in hz fast fourier transform mel frequency in hz global distance hidden markov models number of frames number of samples in each frame local distance linear predictive coding number of samples that separated frames mel frequency cepstral coefficients recognition rate voice activity detection sequence feature vector in n dimensional space another sequence feature vector in n dimensional space 1. introduction the arabic language is the fifth widely used language world-wide since there are at least 200 million people speak arabic, (khalid, 2013). there are little researches in speech recognition field that deal with arabic as compared to english or japanese. the arabic language has monosyllabic and polysyllabic words with two categories of phonemes: pharyngeal and emphatic, which found in all semitic languages, (al-zabibi, 1990) and (alkhouli , 1990). the automatic speech recognition, which got a good attention for many decades, allows a computer to recognize spoken words inputted by a mike. speech recognizers are used in many applications such as: interacting with deaf people, healthcare, home automation, robotics, etc. there are a large number of approaches for speech recognition such as: dynamic time warping (dtw), artificial neuralnetwork (ann), hidden markov models (hmm), etc. in this work, an efficient dtw-based speech recognition system for isolated arabic words is given as a feature matching algorithm and a mel frequency cepstral al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 137 coefficient (mfcc) approach is used as a feature extraction approach because of its robustness and effectiveness compared to other well-known methods like linear predictive coding (lpc), (lindasalwa, 2010). after that a mobile robot is designed, as will be explained in the subsequent sections, and controlled by the designed speech recognizer to get a complete speech controlled system suitable for different applications. it is desired to command the mobile robot by voice via special interface that plays a significant role as a master control circuit for the servo motors of the robot. in voice control system, a difficulty may appear in the control circuit leading to a recognition error, which means that the recognized command is interpreted as opposite command. for example "left" is interpreted as "right" especially in languages with very high acoustic similarity like polish. this problem is not significant in arabic when using the direction words because they differ completely in pronunciation. unlike other languages, arabic language is characterized by having tremendous dialectical variety, diacritic text material, morphological complexity which may lead to some challenges against having a highly accurate arabic recognizer. in the work of (jean-marc , 2007), the voice of the speaker depends on the distance and azimuth. the work satisfied a distance of 2m and azimuth range of 10 o to 90 o . in 2010, two voice recognition algorithms which are mfcc and dtw is built, evaluated and compared with other techniques to prove their effectiveness, (lindasalwa, 2010). in 2011, (ahmed,2011) had proposed a technique called (multiredgilet transform) with neural network to control the motion of a wheelchair dedicated for handicapped people. the work presented by (rachna, 2011) is to build a microcontroller-based mobile robot controlled with speech. he studied various factors such as noise and distance factor for his speech recognition system. (khalid, 2013) suggested dtw, mfcc and voice activity detection (vad) for isolated words of arabic language but with unsufficient recognition rates. in our work, we built a speech recognizer using mfcc, dtw, and vad for five arabic words and a high recognition rates are satisfied without depending on azimuth and the distance is limited by the wireless transmission distance. this speech recognition system is used to control the motion planning of an autonomous mobile robot designed completely to get a voice controlled robotic system. the rest of the paper is organized as follows: section 2 is concerned with the explanation of our speech recognition system with all its stages. in section 3, the complete design of the mobile robot with the used components is explained. section 4 provides the software structure of the overall system. in section 5, the obtained results and verification are given with some required discussion. section 6 summarizes the main conclusions. 2. the voice recognition system the presented arabic speech recognition system consists of the following stages: a. preprocessing this stage is important to enhance the recorded speech signal characteristics by removing noise leading to obtain a high quality recorded speech. the high frequency contents of the input signal are emphasized by a first order fir filter (implemented in software) to flatten the signal spectrum. also, this stage should overcome the problem of using different types of microphones and different speaking loudness. this stage is hidden in the first stage "read the voice input" of figure1. b. voice activity detection (vad) another problem that affects the performance of the speech recognizer is detecting the start and end points of the voice signal, (khalid, 2013). the speech signal is segmented into spaced frames of 10ms al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 138 width. after that, short-term power and zero-crossing rate are used to detect the speech/non-speech regions. it is clear that short-term power is increased in speech regions while zero-crossing rate is increased in non-speech regions. hence, these two techniques give a good indication of speech appearance. c. feature extraction  framing: the speech signal is segmented into k frames of l samples for each one. the adjacent frames are separated by m samples (m<l). in this work, values of l=256 and m=87 samples are chosen.  hamming window: it is applied to the above framed signal to reduce the discontinuity at both ends of each frame.  fast fourier transform (fft): it is used to convert the above windowed signal from time domain to frequency domain to prepare it for the next stage.  mel filter bank: since human hearing is less sensitive to frequencies higher than 1khz, a melscale is used so that for each tone with a frequency f (in hz), a subjective pitch is measured on a mel-scale according to the following equation, (plannerer, 2005): (1) after calculating of the magnitude of the resulting fft signal and using the mel-scale filter bank, which consists of 24 triangular band pass filters having an equal spacing before 1 khz and logarithmic scale after 1 khz, the mel spectrum coefficients are found as the summation of the filtered results.  inverse discrete cosine transform (idct): it is used to return back to time domain. but before that, the logarithm of the magnitude of the output of mel-filter bank is computed since logarithm compresses the dynamic range of values.  liftering: is a filtering in the spectrum domain that used to extract the vocal tract cepstrum. some cepstrum coefficients at the end can be dropped. one can use the first 12 coefficients for each frame and neglect the others. d. database collection a feature database of spoken arabic words for pattern matching process is created and stored in computer memory as a collection of template vectors. feature database is built by recording several utterances for each one of the five target words collected from different speakers (male and female) during the training process. after each target word is recorded, preprocessing, vad, and feature extraction processes are performed and the final feature vector pattern is obtained and stored in the database. for each of the adopted arabic control target words, fifteen patterns, template vectors were created in this manner. thus the training database of feature vectors contains 75 patterns arranged as five cluster one for each control word. all recording sessions are done under normal environment with 8 khz sampling frequency and 8 bit per sample mono channel. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 139 e. feature (pattern) matching pattern matching process is performed in the runtime phase of the proposed system to find the template pattern that best fit to the spoken word. pattern matching is done in online manner. the test spoken word is recorded in the same environment used for training phase. the test feature vector is then found after applying preprocessing, vad, and feature extraction steps. test feature vector is compared with all template vectors in the training database vector by vector. the best fit template vector is selected. the target word for which the best fit template belongs in is said to be recognized. the time alignment of different utterances is the core problem for distance measurement in the speech recognizer presented in this paper. a small shift leads to incorrect identification. dynamic time warping (dtw) is an efficient method to solve this problem, (shivanker, 2013). dtw algorithm aims to align two sequences of feature vectors by warping the time axis repetitively until an optimal match is found. in other words, it performs a piece wise linear mapping of the time axis to align both signals. if two sequences of feature vector in n-dimensional space is considered: (2) then they are aligned on the sides of a grid. the distance between two points is obtained by the euclidean distance: (3) the best match or alignment between these two sequences is the path through the grid, which minimizes the total distance between them. the overall distance (global distance) is calculated by finding and going through all the possible routes through the grid, each one compute the overall distance. then global distance is obtained by the following recursive equation: (4) gd=global (overall) distance, ld=local (euclidean) distance. 3. the mobile robot system a. the robot vehicle the used vehicle is a new breed of tracked robot chassis designed specifically for mobile robot projects, (rover 5, 2013) as shown in figure 2. it has two actuated wheels and two passive wheels used for balance. the clearance can be adjusted by rotating the gearboxes in 5-degree to maintain tension as required. an optical quadrature encoder that gives 1000 pulses over 3 revolutions of the output shaft is embedded. it has two motors and encoders and 4 noise suppression coils. b. the vehicle motors and motors' driver the two motors used in this car are servo motors with the following specifications: motor rated voltage is 7.2v, stall current is 2.5a, output shaft stall torque is 10kg/cm, and speed is 1km/hr. the motor driver is based on the l298, which is a dual h-bridge driver designed to drive inductive loads such as al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 140 dc and stepping motors, (user's guide, 2012). it lets you drive two dc motors, controlling the speed and direction of each one independently. the connection diagram of the driver with the two motors and a real photo of it are shown in figure 3. c. the robot controller circuit the brain of the robot that is considered as a decision making element and controls the motion planning of the robot is the microcontroller. pic18f45k22, (microchip technology inc., 2012), is one of the most popular microcontrollers that could be adopted in robotic systems. in this project, we used the easypic7 development board, (user's guide mikroelektronika, 2013), which will save effort and time for building a complete controller and interface circuit. it has an rs232 port for uart serial communication with the computer as shown in figure 4. since there is no rs232 serial port in our notebook computer, a usb-to-rs232 converter is used. to facilitate the serial communication between the speech recognizer designed with matlab and the microcontroller-based interface circuit of the mobile robot, the following code is embedded within the speech recognizer: command=?; s=serial('com1'); fopen(s); fwrite(s,command); fclose(s); delete (s); where: "command" is the value that corresponds to the desired direction given acoustically by a person. "com1" is the serial port number available, which may take other numbers depending on the computer. d. the microphone a quality microphone is the key when utilizing automatic speech recognition (asr). in most cases, a desktop microphone is not sufficient because they may pick up more ambient noise that gives asr programs a hard time. hand held microphones are also not the best choice as they can be cumbersome to pick up all the time. while they do limit the amount of ambient noise, they are most useful in applications that require changing speakers frequently. the best choice and the most common is the headset style. it allows the ambient noise to be minimized, while allowing us to have the microphone at the tip of our tongue all the time. logitech wireless headset h600 (shown in figure 4) is found experimentally to be the best choice, so it is used to control the robot while it is moving. the headset will send the voice orders to the robot as a response to a low sound tone that tell us when one can start speaking. this headset consists of the following parts: nano usb receiver plugin in the notebook computer, noise-canceling microphone, 2.4 ghz wireless transmitter, simple on-ear control, and sixhour rechargeable battery. e. the notebook computer it is a 10 inches laptop computer with usb ports for serial communication with the microcontroller of the robot and for the nano receiver of the headset. a matlab r2010 is installed to be the environment of the speech recognizer that takes the input voice from our wireless mike and produces the corresponding commands outputted via the usb port to the interface circuit reaching to the microcontroller which in turn interprets these commands and produces the suitable action for the motors to begin the planned motion. the block diagram of the overall computer control hardware system is shown in figure 5. of course, this laptop has a relatively large size the matter that may restrict the robot usage to some applications but it is desirable to other applications that need a computer controlled robots such as moving robots in space (que, 2011), and industrial robots (yoshioka , 2014). http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.yoshioka,%20t..qt.&newsearch=true al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 141 4. the overall software structure voice recognition works based on the premise that a person voice exhibits characteristics that are unique among different speakers. the signal during training and testing sessions can be greatly different due to many factors such as: people voice change with time, health condition, speaking rate and also acoustical noise and variation recording microphone. to explain the software stages starting from voice input to commands output, a flowchart is shown in figure 1. the microcontroller should be programmed in order to receive the commands from the serial port and use them to actuate (drive) motors accordingly. microc is a powerful, feature rich development tool for pic micros designed to provide an easy solution for developing applications in embedded systems and control, (user's manual of mikroelektronika, 2012). the c program downloaded inside our pic is given below: char uart_rd; void main() { anselc = 0; uart1_init(9600); delay_ms(100); trisb = 0x00; latb = 0x00; while (1) { if (uart1_data_ready()) { uart_rd = uart1_read(); latb =uart_rd; }}} 5. results and discussion in order to evaluate the performance of the presented speech recognizer, recorded samples are separated into training and testing sets. the recognition rate of each arabic word can be calculated by the following equation, (khalid, 2013): *100% (5) each word of the five arabic words is trained fifteen times to provide sufficient number of template vectors for four different cases of experimental work. hence, the number of stored templates is 75. in the test phase, each of the five words is tested at run time of the mobile robot that operates 30 times. mobile robot motion with respect to the corresponding voice command is monitored and recognition accuracy (recognition rate) is computed. table 1 shows the rr for a sample of tested words in the database which have been already recorded. while table 2 shows the elapsed time required to perform the matching process for four different cases use 3, 5, 10, or 15 template vectors for each word. from table 1, three template feature vectors per target word give poor recognition rate. rr is significantly increased with 5 template vectors. using 10 template vectors give very good rr. increasing the number of template vectors to 15 led to little increasing in the recognition rate as shown in figure 6. on the other side, the time needed for dtw to perform the matching process for the four defined cases seems to vary in approximately linear form as shown in figure 7. from the held experiment with results given in table 1 and table 2, using ten template feature vectors per word gives very good rr with moderate time. the input voice waveforms of the five spoken words are shown in figures 8-12. now, the presented speech system is applied to the motion of the designed mobile robot which is tested with the five arabic words in table 1. it is possible with a series of voice commands to steer al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 142 the robot along a desired trajectory to its target. also, controlling the voice commands leads to control motion and avoid obstacles in the way of the robot. to satisfy a linear path for the robot, only the isolated words "امام" or "خلف" is used (both wheels are rotated clockwise or anti-clockwise) as shown in figure 13. circular path of the robot is obtained by a single isolated voice command "يسار" or according to the desired direction. figure 14 shows circular motion of the robot in clockwise "يمين" direction using voice command "يمين" in which right motor is "off" and left motor is "on". 6. conclusions using a simple and efficient automatic speech recognition technique for isolated arabic words to satisfy the motion planning of mobile robots is the interest of this paper. the extracted features are stored in a .mat file using mfcc algorithm. the experiment results are analyzed with the aid of matlab and proved good efficiency especially when applied with the designed mobile robot. this process can be extended for a number of speakers. also, the work proved that the dtw is a sufficient nonlinear feature matching technique in speech identification with minimal error rates and fast computing speed the matters that are very important in robotics. generating database stores feature vectors to be matched with run time test words rather than storing the whole speech signal saved memory space and made matching process very fast. the processing units (the notebook and the microcontroller) are directly attached to the mobile robot in one package that made the design representing a complete autonomous robot. voice commands are given using wireless microphone results in flexible movement of the robot. the range of movement of the implemented mobile robot is only restricted by the range of the wireless microphone. the physical range of movement can be extended simply by speaker movement because there is no fixed station is used for any processing purpose. references ahmed q. a., 2011, controlled of mobile robots by using speech recognition, journal of babylon university, applied science, vol. 3, issue 19. alkhouli m., 1990, alaswaat alaghawaiyah, dar alfalah, amman, jordan, (arabic reference). al-zabibi m., 1990, an acoustic-phonetic approach in automatic arabic speech recognition, the british library in association with umi, uk. jean-marc v., shun’ichi y., jean r., francois m., kazuhiro n., and hiroshi g., 2007, robust recognition of simultaneous speech by a mobile robot, ieee transactions on robotics, vol.23, no.4. p. 742-752. khalid a.d., ala f., iyad f., baraa a., and saed w., 2013, efficient dtw-based speech recognition system for isolated words of arabic language, world academy of science, engineering and technology, vol. 7, p. 106-113, iraq. lindasalwa m., mumtaj begam and i. elamvazuthi, 2010, voice recognition algorithms using mel frequency cepstral coefficient (mfcc) and dynamic time warping (dtw) techniques, journal of computing, vol.2, issue 3, issn 2151-9617. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 143 microchip technology inc., 2012, low power, high performance microcontrollers. plannerer b., 2005, an introduction to speech recognition, bernd plannerer, munich, germany. que d., jian yang ; bo wei ; hui li ; zhihong jiang ; danfeng li ; hongjie li ; qiang huang, 2011, a method on trajectory plan for humanoid space robot , robotics and biomimetic (robio), ieee international conference, p. 281-286. thailand. rachna j., and saxena s., 2011, voice automated mobile robot, international journal of computer applications (0975-8887), vol. 16, no. 2, india. rover 5, available at: https://www.sparkfun.com/products/10336 shivanker d., geeta n., and poonam p., 2007, isolated speech recognition using mfcc and dtw, international journal of advanced research in electrical, electronics and instrumentation engineering, vol.2, issue 8, 2013, iso 3297: certified organization, india. user's guide, 2012, l298 dual h-bridge motor driver. user's manual, 2012, microc: c compiler for microchip pic microcontrollers, mikroelektronika, belgrade. user's guide, 2013, easypic7", mikroelectronika, belgrade. yoshioka, t. ; shimada, n. ; ohishi, k. ; miyazaki, t. ; yokokura, y., 2014, link-coupled vibration suppression control considering product of inertia for industrial robots, advanced motion control (amc), ieee 13th international workshop, p. 675 – 680, yokohama, japan. table (1): recognition rates for different feature sets tested arabic words transcription english writing rr 3 5 10 15 امام amam forward 43 67 90 93 khalf backward 40 63 80 80 خلف yemeen right 46 73 86 90 يمين yesar left 53 83 90 93 يسار qif stop 46 67 83 86 قف http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.jian%20yang.qt.&searchwithin=p_author_ids:37538613900&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.bo%20wei.qt.&searchwithin=p_author_ids:38236767200&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.hui%20li.qt.&searchwithin=p_author_ids:37407161800&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.zhihong%20jiang.qt.&searchwithin=p_author_ids:37405774600&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.danfeng%20li.qt.&searchwithin=p_author_ids:37535499900&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.hongjie%20li.qt.&searchwithin=p_author_ids:38240925400&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.qiang%20huang.qt.&searchwithin=p_author_ids:37279982900&newsearch=true http://ieeexplore.ieee.org/xpl/articledetails.jsp?tp=&arnumber=6181299&querytext%3dspace+robot https://www.sparkfun.com/products/10336 http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.yoshioka,%20t..qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.shimada,%20n..qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.ohishi,%20k..qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.miyazaki,%20t..qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=p_authors:.qt.yokokura,%20y..qt.&newsearch=true http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=6815878 http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=6815878 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 144 table (2): feature matching time for different cases no. templates comparison time (msec) 3 5.8 5 9.4 10 15.2 15 23.7 figure (1): the overall software system al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 145 power control lines figure (3): motors driver connection diagram and its real photo figure (2): the robot chassis figure (4): the overall designed listening robot with its main parts al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 146 figure (8): the input voice signal of "امام" word figure (9). the input voice signal of "خلف" word figure (5): the overall hardware system left motor of robot right motor of robot rs232 figure (6): relationship between rr and no. of template vectors figure (7): relationship between time and no. of template vector al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 147 0 1000 2000 3000 4000 5000 6000 7000 8000 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 figure (10): the input voice signal of "يسار" word figure (11): the input voice signal of " ميني " word figure (12): the input voice signal of "قف" word figure (13): linear path navigation of the mobile robot figure (14): the circular path navigation of the mobile robot y x al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 239 noise levels assessment in selected places in al-diwaniyah city, iraq hussein janna* *civil engineering department, al-qadisiyah university, al-diwaniyah, iraq corresponding author: dr. hussein janna e-mail: hussein.janna@qu.edu.iq received 3 march 2016 accepted 24 march 2016 abstract: nowadays, noise becomes one of the most environmental pollutants. several adverse effects linked with exposure to environmental noise. the aim of this study was achieved to evaluate noise level in some selected area represented by schools and medical centres in al-diwaniyah city according to the international standards. therefore, noise levels were measured using sound level meters type (svan-955) in 10 places (5 schools and 5 health centres and hospitals) in different areas in the city. most of these selected schools and health centres were exposed to noise from road traffic. the study revealed that equivalent sound level and minimum sound level for the schools (65dba, 59dba respectively) exceeded the international standards. the equivalent and minimum noise level in the health centres were (66dba, 59.6dba) also exceeded the who, usepa and european legislations. therefore, these results will be of help to planners and policy makers in the city to combat such this problem and take the necessary actions to legislate the iraqi standard for noise exposure and also to reduce the impact of noise on the buildings and common places. keywords: sound level, al-diwaniyah, schools, health centres, noise pollution. تقييم مستوى الضوضاء الماكن مختارة في مدينة الديوانية في العراق د. حسين علي جنة جامعة القادسية –كلية الهندسة –قسم الهندسة المدنية العراق -الديوانية hussein.janna@qu.edu.iq الخالصة في ايامنا هذه, اصبح الضجيج )الضوضاء( من اكثر الملوثات البيئية تعقيدا, هنالك العديد من صالت الربط والعالقة بين التاثيرات ن التعرض للضوضاء. لذلك فان الغرض والهدف من هذه الدراسة هو لتقييم مستوى الضوضاء في السلبية على الصحة والبيئة وبي من مدينة الديوانية متمثلة بمجموعة من المدارس ومجموعة اخرى من المراكز الصحية والمستشفيات وفقا للمعايير اماكن مختارة ( في svan-955باستخدام مقياس مستوى الصوت نوع )والمواصفات الدولية. ولذلك فان مستويات الضوضاء قد تم قياسها عشرة اماكن ) بضمنها خمسة مدارس وخمسة مراكز صحية أو مستشفيات(. معظم هذه االماكن ) المختارة( تتعرض للضوضاء لمدارس نتيجة لحركة ومرور السيارات . بينت نتائج هذه الدراسة ان مستوى الصوت المكافئ والحد االدنى لمستوى للصوت في ا على التوالي والتي تجاوزت الحدود والمواصفات الدولية. باالضافة الى ذلك, فقد كشفت النتائج 59dbaو 65dbaكان بمعدل mailto:hussein.janna@qu.edu.iq al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 240 عن ان مستوى الصوت المكافئ وكذلك الحد االدنى لمستوى للصوت في المراكز الصحية والمستشفيات قد تخطى حدود مواصفات على التوالي. 59.6dbaو 66dbaات البريطانية ومنظمة حماية البيئة االميركية وبواقع منظمة الصحة العالمية والمواصف وبناءا على ما تقدم فان مثل هذه النتائج تساعد اصحاب القرار والمخططين التخاذ االجراءات والتدابير الضرورية والتي من شانها ع الحدود والمواصفات للتعرض للضوضاء في تلك االماكن. الحد من التعرض للضوضاء في تلك االماكن وتشريع القوانين ووض باالضافة الى دراسة امكانية دعم وتطوير البحوث واستخدام لمواد بناء واليات ووسائل بما يسهم من التقليل من تاثير تلك المستويات على تلك المؤسسات واالماكن العامة. 1. introduction: contaminants which cause adverse change into the natural environment and can take the form of chemical substances or energy, such as noise, heat or light. “nausea” is a latin word means ‘unwanted sound’ or ‘sound that is loud, unpleasant or unexpected where the word “noise” come from [1]. the unwanted sound is defined as a noise. all the unwanted sounds in our communities except that which originates in the workplace represent environmental noise. environmental noise pollution is a risk to health and well-being. environmental noise is recognized as a major health problem[2]. the problems with noise pollution have often been given similar concern ratings as those for global warming especially in european union (eu) [3]. sound is the result of pressure variations in a medium – typically air. pressure fluctuations above and below atmospheric pressure are detected by the human ear and this results in the sensation of hearing [4]. there are many concepts that providing a very useful mean of describing sound fluctuations. sound is commonly measured using the decibel [db] scale. in terms of environmental noise the sound pressure level, spl, in decibels is calculated from: spl= 10 log10 (p/p0) 2 [db] where p is the sound pressure being measured and p0 is the reference sound pressure ;( 20 mpa)[4]. equivalent continuous sound level (leq) is defined as the steady sound pressure level that has the same total energy as the actual fluctuating noise over a given period of time, which is in fact the rms sound level with the measurement duration used as the averaging time. sound exposure level (sel) is defined as that constant sound level which has the same amount of energy in one second as the original noise event. therefore, sel is similar to leq in that the total sound energy is integrated over the measurement period, but instead of then averaging it over the measurement period, reference duration of 1s [5]. there are various sources of noise that can affect the community. namely, noise comes from industry, transportation, construction noise and from domestic and leisure activities. transportation noise is the main source of environmental noise including road traffic, rail traffic and air traffic. road traffic noise is a combination of noise resulting from the vehicle’s engine noise and noise due to the interaction between the tyres of the vehicle and the road surface[6]. in 2006, an investigation study found that there is a variation in noise levels within different types of tyre (between 6 and 8 db within certain tyre) in the eu[7]. many researchers have studied and evaluate the noise pollution internationally and nationally. for example, romania [8, 9],greece [10], sweden [11], united kingdom[12] and brazil [13]. in countries with social problems such as iraq, urban noise has not been receiving enough attention. however, there are some researchers have shown the problem of environmental noise such as in jordon [14], egypt[15] , saudi arabia[16], and in iraq such as baghdad [17, 18], mosul [19], and sulaimani [20]. there are several national and international guidelines relating to the acoustics of classrooms and hospitals, and because of the differences in lifestyle, climate (outdoor activities, open or closed windows) and building design make international agreements of noise limits impossible. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 241 the aim of this work is to evaluate the noise level in some selected area in al-diwaniyah city and how it is compliance with the international guidelines. 2. methodology: the noise pollution could affect many different places (schools, hospitals, health centres) in different time during the year, however, in this study; only five schools and five health centres in the city of al-diwaniyah, iraq, were chosen to measure the noise around these buildings. although there are few schools and health centres existed in quite area, however, the majority of buildings (schools and health centres) are existed on the main roads and therefore the selected schools and health centres were located on tow –way direction road. figure (1) shows the map of the selected places where the noise level were measured. the time for each measurement was 15 minutes and each measurement consists of 30 readings (every 30 seconds), the measurements were repeated for five days (during the working days). therefore, it is about 150 readings, in total, were measured in different schools and health centres. noise parameters were recorded in every measurement in dba were: equivalent level( leq), peak noise level (lpk), maximum noise level (lmax ) and minimum noise level (lmin). during the measurement's days there was no rain or significant winds. measurements were undertaken between (8:30am and 11:30am) during working days. noise measurements commenced in morning with the start working hours in front of the school and health centres. wherever possible, the sound level meter was placed more than (1m) away from the nearest classroom or the window of the health centre wall, to avoid the impact of reflected sound. the height of the sound level meter was (1.6 m). due to the logistic issues; it was difficult to record the sound level in the hospitals and health centres at night and for long periods. readings were achieved during the actual operating hours of the school and health centres. the measurement was performed using sound level meters (svan 959), poland as shown in figure (2). the device of (338*82*42 mm) in dimension, the svan 955 is all digital, and its weight about 630 gm including, microphone, preamplifier and tripods. the device can be used at a different climate condition in terms of temperature which from 10-50 c° and humidity up to 90%. the total dynamic range: 15 dba rms to 141 dba peak as a measurement range. the sound level meters operated in fast mode using the a weighting filter. data were tabulated and analysed using simple descriptive statistics. independent (unpaired) ttest for two means and analysis of variance for multiple means were used. p≤0.05 were considered significant throughout data analysis. 3. results and discussion the results will present the noise around selected schools, and the noise around selected hospitals and health centres. 3.1noise at schools the average values of the equivalent level of the traffic noise pollution in the selected schools for the five days (during the working days (sunday thursday)) were tabulated in the table (1). table (2) shows the minimum, maximum, and peak values of the sound level. it is important to mention that during the sport classes and pupils breaks; there was no measuring for the sound level meter. from the average values of the equivalent level for all the selected schools, it can be seen that the average values (about 65dba) were exceeded the international a standards, since the who al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 242 guideline recommends that the noise level in the school playgrounds should not exceed 55dba and 35dba during the teaching sessions[6]. while the american national standards recommend about 35dba in the classroom [21]. it is also noted that the average equivalent of these selected schools were exceeded the european legislation standards (average of 35dba)[2], as shown in figure (3). unfortunately there is no iraqi guideline for the noise level in common places such as schools and hospitals. the statistical analysis of the data show that there is a significant difference in the mean equivalent value only between damascus with dar al-salam school and between damascus and almarkaziyah schools due to the fact that the classroom are slightly far from the main road (in damascus school about 20m) and also due the face the dar al-salam school location is surrounded by many different governmental authorities. in addition to that almarkaziyah school is very close to the commercial zone within the city and therefore different cars and trimotor cycles are passing close to the school. however, there is no significant difference between the mean averages of all the minimum values among the schools, which mean that all the school have been exposed to the same level of noise (same baseline of noise).the results were in compliance with other study carried out in baghdad [17]. in noisy environments, children have poor school performance leading to stress and misbehaviour [22]. they also have decreased learning, and concentration deficits [23]. therefore more attention should be paid to eliminate this issue. 3.2noise at health centers the mean values of the equivalent level due to the traffic noise pollution in the selected hospitals and health centres for the five days (during the working days were tabulated in the table (3). the table (4) shows the minimum, maximum, and peak values of the sound level. from the average values of the equivalent level for all the selected health centres and hospitals, it can be seen that the average values (about 66 dba) were exceeded the international a standards, since the who guideline recommends that the noise level in the hospitals should not exceed 35dba. while the united states environmental protection agency (usepa) recommend about 40dba in the hospitals [24]. it is also noted that the average equivalent of these selected places were exceeded the uk legislation standards (30dba) as shown in figure (4). there is no iraqi guideline for the noise level in the health centres and hospitals. the statistical analysis of the data shows that there is no significant difference in the mean equivalent value among the selected hospitals and health centres. in addition, there is no significant difference between the mean averages of all the minimum values among the selected health centres, this mean that all the selected places have been exposed to the same background level of noise. it is interesting to note that the measurements on tuesday were higher the rest of the working days significantly in the all selected places. the results were in accordance with another study that measuring the noise level in the main roads and streets that some of these selected schools and health centres exist on them. the results of this study were in compliance with the other studies achieved in other cities in iraq, since it was in compliance with that one in sulaimani [20]. however, it was lower that what they found in mosul [19] and that might be due the differences in population, cars type and account and also in the locations of the selected places. several adverse effects linked with exposure to environmental noise. these can range from hearing loss to sleep disturbance to annoyance and even cardiovascular disorders. the most predominant community response in a population exposed to environmental noise is annoyance. noise annoyance can result from noise interfering with daily activities, feelings, thoughts, sleep, or rest, and might be accompanied by negative responses, such as anger, displeasure[11]. the most significant effects of environmental noise on health come in the form of annoyance and sleep disturbance. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 243 3. conclusions and recommendations the study includes five schools and five health centres were having selected to evaluate the sound pressure level in al-diwaniyah city. the results obtained show that the schools that were exposed to high level of noise (about 65 dba) when it compared with the international standards, where the minimum sound pressure levels were also exceeds the limits of who, usepa, and united kingdom standards. the statistical analysis of the results shows that there was significant difference between some schools due to either their location that surrounded by governmental or commercial area or because of the distance of the classroom to the main road. in terms of minimum sound level, there was no significant difference between selected schools and that reflect the same level of noise background that these schools are exposed. all the noise level around the hospitals and health centres (66dba) exceeded the international standards. therefore, these results will be of help to planners and policy makers in the city to combat such this problem. consequently there some recommendations should be considered are: 1take the necessary actions to reduce the impact of noise on the buildings like providing dense trees as a sound barrier, in addition to consider the types of walls, floors and ceilings, windows and doors that provide better damping to the external noise as an acoustic insulation technique. 2undertake another study to assess the rest of the other authorities like police stations, universities, and some roads, intersection and roundabouts to draw a pic picture of the noise distribution around the city and find the solution to solve this issue especially with the traffic noise. 3the development of environmental awareness and the creation of basic environmental knowledge in order to develop a positive environmental behaviour as a basic requirement that the citizen can effectively play its role in protecting the environment, thus contributing to the preservation of public health. 4legislate the noise level standards for the common building and places by monitoring the sound level and establishing the suitable environment for each facility taking in the account the effect of places, type of authority, type of noise, weather and the construction of these building in order to generalize that to be as a baseline to start with for buildings in the future. 5a combination of strategies that include noise barriers, lower vehicle noise levels and better urban planning should be applied in order to reduce the noise pollution. 6there is a need to study the noise level especially around hospitals in the night to see the pattern difference in sound level between day and night. 4. acknowledgements wish to acknowledge the support of al-qadisiyah authority for environment for their support about providing the sound level meter devices, and the engineers that help in achieve this work. references [1] singh, n. and s.c. davar, noise pollutionsources, effects and control. journal of human ecology, 2004. 16(3): p. 181-187. [2] vallet, m. and z. karabiber, some european policies regarding acoustical comfort in educational buildings. noise control engineering journal, 2002. 50(2): p. 58-62. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 244 [3] calm, research for a quieter europe in 2020. strategy paper of the 519 calm ii network, 2007. european commission(brussels). [4] murphy, e. and e.a. king, environmental noise pollution: noise mapping, public health, and policy. environmental noise pollution: noise mapping, public health, and policy. 2014. 1-268. [5] bernard, p., leq, sel what? why? when? brüel & kjær sound & vibration measurement, 2003. 8(bo 0051-14). [6] berglund, b., t. lindvall, and d.h. schwela, guidelines for community noise archives of the center for sensory research. vol. 2. 1999. [7] sandberg, u., tyre/road noise – myths and realities. literature survey, final report si2.408210, 2006. vol. 2 brussels. [8] tania, m.i. and r. mih£¿iescu, traffic noise pollution in urban areas. case study ¨c bistrita town. proenvironment promediu, 2009. [9] popa, d., m.t. corches, and a.g. buzgar, evaluation of environmental noise pollution caused by road traffic in the city of alba iulia, romania. journal of environmental protection and ecology, 2015. 16(3): p. 824-831. [10] sarantopoulos, g., s. lykoudis, and p. kassomenos, noise levels in primary schools of medium sized city in greece. science of the total environment, 2014. 482: p. 493-500. [11] ohrstrom, e., et al., effects of road traffic noise and the benefit of access to quietness. journal of sound and vibration, 2006. 295(1-2): p. 40-59. [12] shield, b. and j.e. dockrell, external and internal noise surveys of london primary schools. journal of the acoustical society of america, 2004. 115(2): p. 730-738. [13] zannin, p.h.t., f.b. diniz, and w.a. barbosa, environmental noise pollution in the city of curitiba, brazil. applied acoustics, 2002. 63(4): p. 351-358. [14] jamrah, a., a. al-omari, and r. sharabi, evaluation of traffic noise pollution in amman, jordan. environmental monitoring and assessment, 2006. 120(1-3): p. 499-525. [15] ali, s.a.a., study effects of school noise on learning achievement and annoyance in assiut city, egypt. applied acoustics, 2013. 74(4): p. 602-606. [16] al shimemeri, s.a., c.b. patel, and a.f. abdulrahman, assessment of noise levels in 200 mosques in riyadh, saudi arabia. avicenna journal of medicine, 2011. 1(2): p. 35-8. [17] jumaa, g.f., evaluation of noise pollution in some schools in baghdad city. engineering and technology journal, 2010. 28(24): p. 10. [18] mohammad, m.k., health impact assessment of noise pollution in baghdad city. journal of college ofeducation, 2010. 6: p. 15. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 245 [19] humam g. al-zubeer , a.a.a.-j., miss raghad a. al-joomard, noise pollution in mosul medical city center teaching hospitals ann coll med mosul, 2013. 39(1): p. 6. [20] parekhan m. jaff, dana a. tahir,and hossien hossieni, study of noise pollution in sulaimani city. waassit journall for science & medicine 2(2): p. 8. [21] usepa noise levels affecting health and welfare. 2016. january 5, 2016. [22] lercher, p., et al., ambient neighbourhood noise and children's mental health. occupational and environmental medicine, 2002. 59(6): p. 380-386. [23] stansfeld, s.a., et al., aircraft and road traffic noise and children's cognition and health: a cross-national study. the lancet, 2005. 365(9475): p. 1942-1949. [24] tijunelis, m.a., e. fitzsullivan, and s.o. henderson, noise in the ed. american journal of emergency medicine, 2005. 23(3): p. 332-335. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 246 table (1): mean equivalent noise levels (leq) in the selected schools in dba with standard deviation. schools day dar al-salam school damascus school al-nahrain school al-markaziyah school al-quds school leq (dba) leq (dba) leq (dba) leq (dba) leq (dba) sunday 66.0 60.2 63.7 67.1 62.8 monday 69.6 60.7 72.9 75.4 63.0 tuesday 64.1 60.0 66.0 69.1 69.0 wednesda y 68.7 60.3 59.8 69.8 61.7 thursday 64.6 63.9 58.8 65.5 61.5 average 66.6 61.0 64.2 69.4 63.6 std 2.5 1.7 5.7 3.8 3.1 table (2): the mean minimum (lmin), maximum (lmax), and peak (lpk) noise levels for selected schools in dba. schools day dar al-salam school damascus school al-nahrain school al-markaziyah school al-quds school lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) sunday 60.8 75.1 88 54.6 67.4 82.8 56.8 72.4 84.2 57.4 71.8 85 58 67.4 79.7 monday 62.6 75 87.9 57.1 66.9 79.7 61.1 76.4 89.8 59.8 71.2 84.4 58.8 71.2 85.8 tuesday 59.5 71.7 85.3 55.1 68 83.8 57.3 75.7 89.7 62.5 78 91.1 62 78.6 91.6 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 247 wednesda y 62.4 77.9 90 56.6 67.3 82.2 54.2 67.9 82.4 63.7 78.2 90.6 57.9 69.4 83 thursday 58.5 72.2 86.5 60.4 71.6 85.8 52.4 68.7 82.2 60.2 73.2 86 58.1 67.7 81.4 average 60.8 74.4 87.6 56.8 68.2 82.9 56.4 72.2 85.7 60.7 74.5 87.4 59 70.9 84.3 std 1.8 2.5 1.8 2.2 1.9 2.3 3.8 3.9 3.3 3.2 3.4 2.5 4.7 4.6 1.7 table (3): mean equivalent noise levels (leq) in the selected hospitals in dba with standard deviation. hospitals day al-jazaar health center al-jamhoori health center special center for dentistry maternity and child hospital emergency ward of al-diwaniya hospital leq (dba) leq (dba) leq (dba) leq (dba) leq (dba) sunday 54.7 67.1 57.9 62.3 59.9 monday 58.3 61.2 61.5 68.2 62.3 tuesday 72.6 70.4 73.7 70.1 72.5 wednesda y 62.2 67.7 68.8 69.6 68.3 thursday 59.1 68.9 63.2 60.7 59.4 average 61.4 67.1 65.0 66.2 64.5 std 6.8 3.5 6.2 4.4 5.7 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 248 table (4): the mean minimum (lmin), maximum (lmax), and peak (lpk) noise levels for the selected hospitals in dba. hospitals day al-jazaar health center al-jamhoori health center special center for dentistry maternity and child hospital emergency ward of al-diwaniya hospital lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) lmin (db a) lnax (db a) lpk (db a) sunday 47.9 65.8 90.5 65.6 71.5 94.2 53.6 71.9 88.8 56.7 73.3 91.4 55.4 70.1 88.6 monday 55.8 65.6 85.5 58.9 77.2 90.8 57.4 69.6 92.2 65.9 75.5 91.7 59.5 71.5 90.9 tuesday 66.5 108. 3 123. 6 64.6 95 105. 7 65 90.7 103. 2 62.2 89.6 104. 7 66.2 86.9 98.1 wednesda y 55.5 78.5 101 61 87.8 102. 2 59.7 92.4 104. 9 58.7 88.5 100. 6 60.4 85.5 98.8 thursday 57.8 67.6 84.5 63.6 88.9 104. 3 59.4 70.9 91.2 56.9 70.8 92.7 57.4 68.3 88.6 average 56.7 77.2 97 62.7 84.1 99.4 59 79.1 96.1 60.1 79.5 96.2 59.8 76.5 93 std 16.2 18.2 6.7 6.6 9.5 2.7 7.4 11.4 4.1 6.1 8.8 3.9 5.1 9.0 4.1 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 249 figure (1): map of the al-diwaniyah city with the selected places (google earth) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 250 figure (2): svan sound level meter. figure (3): mean equivalent, minimum and maximum level with the international standards for selected schools. 0 10 20 30 40 50 60 70 80 dar al-salam damascus al-nahrain al-markaziyah al-quds s o u n d l e v e l, d b a schools min. max. leq who standard uk ,who, eu standards al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 251 figure (4): mean equivalent, minimum and maximum level with the international standards for selected health centres. 0 10 20 30 40 50 60 70 80 90 al-jazaar health center al-jamhoori health center special center for dentistry maternity and child hospital emergency ward of al-diwaniya hospital s o u n d l e v e l, d b a hospitals min. max. leq who standard usepa standards uk standards template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 384 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. compressive strength model for concrete containing polyethylene terephthalate (pet) by using ultrasonic pulse velocity rasha jasim, assist. lecture department of civil engineering, university of al-qadisiyah, iraq. e-mail: rasha.jasim@qu.edu.iq mohammed qasim, assist. lecture department of civil engineering, university of al-qadisiyah, iraq. e-mail: mohammed.alkarawi@qu.edu.iq received on 31 july 2017 accepted on 31 october 2017 published on 30 december 2017 doi: 10.30772/qjes.v10i4.487 abstract: this research proposed a model describing the relationship between ultrasonic pulse velocity (upv) and the compressive strength test of concrete containing pet (polyethylene terephthalate). this was achieved by measuring ultrasonic pulse velocity (upv) on this type of concrete and comparing the result of compressive strength tests to clarify the accuracy of the ultrasonic test equation for this type of concrete. waste bottles of water was used in this study by cutting them into laminar form of fibers with zigzag edges in different length (1,2,3) cm for each volume fraction of pet (1%,2% and 3%) by cement weight with fixed width (0.5) cm. then, they were incorporated with the concrete. it was noticed from the laboratory tests results that the relationship upv strength are related together in the volume fraction of 1% for the length 3cm and the correlation factor (r) is equal to 0.94. this indicates a very good exponential relationship between upv and compressive strength. also, the results are compared and discussed with another proposed formula that found in literature. keywords: concrete contain pet, non_ destructive tests, compressive strength, ultrasonic wave velocity (upv). introduction fibre-reinforced polymer (frp) is the alternative techniques in modern life which in continuous progress by using it as a constituent of concrete in the construction industry. significant research studied the destructive tests of concrete contains polyethylene terephthalate waste (pet) such as compressive strength, modules of elasticity, tensile strength and flexural strength. moreover, these tests were examined in many of structural members like beams and columns. the ultrasonic techniques became popular within the civil engineering industry for a wide range of applications including the evaluation of concrete structures and pavements. it was used to evaluate the compressive strength of pet concrete. mailto:rasha.jasim@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 385 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. benosman et al. (2016) studied the properties of pet-mortar composites by destructive and nondestructive testing with different ratio of fibre (0%, 2.5%, 5% and 7.5%). they found the upv values of the pet-mortar composites and compressive strength decrease with an increase in the percentage of the pet waste particles content. lorenzi et al. (2007) created model between upv and compressive strength test. they conducted an analysis for their results in order to understand how the results of upv are affected by differences at concrete conditions. this can lead into a reduction of the mistakes considering the strength estimation. the results showed that there was a good correlation between compressive strength and upv test. al-nu’man et al. (2015) proposed the relationship formulas /curve between upv and compressive strength for concrete having the collection from 18 to 55mpa of concrete strength. after analysing the data, they founded a good correlation between upv and compressive strength of concrete. ammash et al. (2017) study the effect of using plastic waste on mechanical properties of concrete. noticed from laboratory tests that the addition of plastic fibres improves the compressive strength, tensile strength and modulus of rupture of concrete. the aim of this research is to develop a model for the relationship between upv and compressive strength for concrete containing polyethylene terephthalate fibre, and calculate the correlation factor for all the results obtained. different length of fibre was used (1,2,3) for each fibre content (ratio) (1,2,3) %. to determine which ratio gives the closest result between the compressive strength obtained from destructive and non-destructive tests in order to clarify the accuracy of the ultrasonic equation adopted in previous literature. 1. experimental work in the experimental work, 30 cubes were cast and tested in the laboratory to find the compressive strength for destructive and non-destructive tests of concrete, for different waste ratios. the dimensions of cubes were (150×150×150). the age of the test for all samples was 28 days. all the materials used in this study were tested and compared according to the iraqi standard specification requirements. the tested materials are: 1.1. cement ordinary portland cement was used in the experimental work. the chemical and physical tests were conducted in the construction laboratory of concrete /engineering collage/ university of al-qadisiyah . the results satisfied to iraqi specification no.5/1984.the outcomes of the test are shown in table 1. table 1: chemical analysis and physical test results of cement chemical test results oxide percent weight iraqi specification sio2 21.3 cao 64.64 mgo 2.62 ≤5% fe2o3 2.58 al2o3 6.16 loss on ignition 3 ≤4% irresolvable material 1.5 ≤1.5% al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 386 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. physical test results property results iraqi specification soundness (autoclave)% 0.02 ≤0.8 initial setting time (min) 85 ≥45 final setting time (min) 260 ≤600 compressive strength (mpa) 3 days 16.3 ≥15 7 days 23.7 ≥23 1.2. fine aggregate this material was tested and used in the mixture of concrete according to the iraqi specification no.45/1984. the results of fine aggregate test were within zone 2 as shown in the table 2. table 2: grading of fine aggregate test sieve size % of pass iraqi specification 4.75 (mm) 100 90-100 2.36 (mm) 84 75-100 1.18 (mm) 68.7 55-90 600 micron 37.5 35-59 300 micron 9 8-30 150 micron 2.6 0-10 so3 salt result iraqi specification so3(%) 0.16 ≤0.5% 1.3. coarse aggregate according to iraqi specification no.45/1984, the shattered coarse aggregate was used in the mixture and tested. the results of the test are shown in table 3 bellow. table 3: grading of coarse aggregate test sieve size % of pass iraqi specification 37.5 (mm) 100 100 20 (mm) 100 75-100 12.5 (mm) 88.50 9.5 (mm) 33.59 30-6 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 387 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4.75 (mm) 0.5 0-10 2.36 (mm) 0.07 so3 salt result iraqi specification so3(%) 0.09 ≤0.1% 1.4. plastic fiber waste bottles of water were used by cutting them into small fibers with zigzag edges in different length (1,2,3) cm for each ratio of pet (1%,2% and 3%) by cement weight with fixed width (0.5) cm. then, they were added to the concrete mixes. (figure 1 and 2). figure 1: formed plastic fibre figure 2: type of plastic fibre by using theory of archimedes, the density of fibre was equal to 1.01 gm/cm 3. as well as, many tests have been conducted by using tensile test machine such as yield stress, elongation and ultimate stress. the results of these tests were equal to 7.15 kn,8 mm and 8.25 kn respectively. 1.5. mixing, casting and curing the concrete reference mix consists of cement, sand and coarse aggregates with no fiber. the dry materials were mixed together then; the plastic fiber were gradually added to the mix to avoid blocking of concrete. finally, the water was added to the dry materials and the mixing continued to produce homogeneous mix. the fresh concrete was cast into the moulds immediately after mixing, in three layers for cube specimens. 2. result and discussion the following laboratory tests were implemented in the university of al-qadisiyah / college of engineering. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 388 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2.1. compressive strengths test the average of three specimens results from compressive strength test was recorded and listed in table 4. 2.2. ultrasonic pulse velocity test ultrasonic pulse velocity (upv) test mainly measures the speed of electronic wave through composite concrete. the ultrasonic pulse velocity tests are summarized by placing transducers in the same direction in opposite face of each face as shown in the figure (3) . this method is called direct transmission. it gives a more accurate results than other method. during the test, the ultrasonic waves are passing from one transducer to the other. the time of the traveling the waves was recorded from one surface to the other and measured the distance between the two faces of the cubes. in this way, the velocity of the ultrasonic wave can be calculated. the results of ultrasonic pulse velocity are listed in table 5. table 4: compressive strength(f'c) for all specimens (mpa) table 5: ultrasonic pulse velocity for all specimens (m/s) age ref. mix upv for 10 mm fibre length upv for 20 mm fibre length upv for 30 mm fibre length 0% 1% 2% 3% 1% 2% 3% 1% 2% 3% 28 days 4.01 3.83 3.87 3.92 3.89 3.65 3.89 3.65 3.87 3.85 3.88 3.73 3.95 3.88 3.78 3.85 3.84 3.88 3.85 3.88 3.78 3.71 4.05 3.79 3.82 3.82 3.82 3.90 3.81 3.93 ref. mix compressive strength for 10 mm fibre length compressive strength for 20 mm fibre length compressive strength for 30 mm fibre length 0% 1% 2% 3% 1% 2% 3% 1% 2% 3% 30.76 30.13 30.58 28.84 31.07 26.53 27.60 23.73 24.98 18.44 31.24 30.89 27.73 29.64 30.76 29.51 28.98 26.27 30.71 16.89 29.69 29.07 26.13 27.78 30.13 25.64 22.22 25.78 26.84 19.78 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 389 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3: ultrasonic pulse velocity device 3. the relationshiop between compressive strength and upv the ultrasonic pulse velocity(upv) can be related to compressive strength of concrete. based on the value of the correlation coefficient (r), the strength of the relationship varies. thus, this relationship is used to classify the sample of the concrete containing pet. for the length 1cm with ratio (1%,2%) there is positive relationship, however this relationship is weak. while the ratio 3% for the same length showed a close relationship as shown in figure 4. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 390 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: relationship between upv and compressive strength for length1cm remark: x axis present pulse velocity and y axis present compressive strength. the value of compressive strength is accounted by exponential relationship curve with upv (see figure 5). the following model (proposed formals) is founded between compressive strength (mpa) and upv (m/s). 1% adding the model is f'c = 18.543e 0.1282v r = 0.0654 …….…(1) 2% adding the model is f'c = 68.916e -0.221v r = 0.4076………..(2) 3% adding the model is f'c= 7.0229e 0.3651v r = 0.5402………… (3) heterogeneous nature of this composite concrete. for the length 2 cm with ratio (1%,2%,3%) there is appositive relationship but is weak as shown in figure below. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 391 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: relationship curve between upv and compressive strength for length 2cm the following model (proposed formals) is founded between compressive strength (mpa) and upv (m/s) 1% adding the model is f'c = 18.293e 0.1349v r = 0.2241…. …... (4) …….…..(5) r=0.1721 2% adding the model is f'c = 9.2203e 0.2867v 3% adding the model is f'c = 0.0034e 2.3244v r = 0.3446 ……….(6) for the length 3 cm with ratio (1%) there is a strong related to each other. the correlation factor (r) is equal 0.94 as shown in figure 6 below: figure 6: relationship curve between upv and compressive strength for length 3cm and ratio 1% while the ratio (2%,3%) of adding pet for the same length (3 cm) is weak. as shown in figure below. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 392 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7: relationship curve between upv and compressive strength for length 3cm and ratio 2%,3% the following model (proposed formals) is founded between compressive strength (mpa) and upv (m/s) ………..(7) r=0.94 1% adding the model is f'c = 5.8908e 0.3821v 2% adding the model is f'c = 247.5e -0.573v r = 0.0268 ….….(8) 3% adding the model is f'c = 0.2501e 1.106v r = 0.324 ………. (9) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 393 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4. comprasion with other modles al-nu’man et al.(2015), equations proposed depended on density of course aggregate factor as shown below: f'c= 8.88 e 0.42 v r= 0.83 for ca =1000 kg/m3 …….…. (10) f'c=0.06 e1.6v r=0.87 for ca= 1200kg/m3 ….……. (11) f'c=1.03 e0.87v r=0.88 for ca= 1300kg/m3 ………… (12) f'c=1.39 e0.78v r=0.84 for ca= 1400kg/m3 …….…… (13) they considered course aggregate content as a key factor that capable to determining the better relationship between upv and compressive strength of concrete. in comparison with data of this research, it could be seen the main factor were fibers plastic content. for lengths (1 and 2) cm increase the ratio of fibers lead to more correlated between upv and compressive strength. in a more suitable way, the previous equations for both lengths can be rewritten as follows: for length 1cm: 1% fibres plastic f'c = 18.5 e0.13v r = 0.07 …....… (14) 2% fibres plastic f'c = 68.9 e-0.22v r = 0.4……....... (15) 3% fibres plastic f'c= 7 e0.4v r = 0.5….…… (16) for length 2cm: 1% fibres plastic f'c = 18 e0.13v r = 0.2…. …. (17) 2% fibres plastic f'c = 9 e0.3v r=0.2………..(16) 3% fibres plastic f'c = 0.003 e2.3v r = 0.35 …….(19) but, the length (3) cm with ratio (1%) achieve the better relationship between point data and slop curve. the correlation factor was equal 0.94. it can be say, this length was as a bridge connecting the components of mixture concrete. in addition, it was filling the gaps inside of the mixture. these gave more continuity to the transmission of waves without interruption. also, in a more suitable way, the previous equations for length (3) cm can be rewritten as follows: 1% fibres plastic f'c = 6 e0.4v r=0.94………… (20) 2% fibres plastic f'c = 248 e-0.6v r = 0.03 …….…. (21) 3% fibres plastic f'c = 0.3 e1.12v r = 0.32 ………. (22) for the reference mixture (0% plastic), the proposal formula was f'c=18e0.14v r² = 0.4 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 394 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 5. comparison e between compressive strength results for destructive and nondestructive test table below shows the result of destructive and nondestructive test. table 6: result of destructive and nondestructive test for all specimens (mpa) 3cm length 2cm length 1cm length 0%( ref. mix) 3% 2% 1% 3% 2% 1% 3% 2% 1% f' cn f' cd f'cn f'cd f'cn f'cd f'cn f'cd f'cn f'cd f'cn f'cd f'cn f'cd f'cn f'cd f'cn f'cd f'cn f'cd 18 .4 17 .6 25.0 27.2 23.7 23.8 27.6 28.5 26.5 26.3 31.1 30.9 28.8 29.3 30.6 30.2 30.1 30.3 30.8 31.1 16 .9 18 .2 30.7 27.4 26.3 25.9 29.0 25.7 29.5 27.8 30.8 30.4 29.6 28.9 27.7 28.3 30.9 29.9 31.2 30.5 19 .8 19 .3 26.8 28.0 25.8 26.1 22.2 24.6 25.6 27.5 30.1 30.6 27.8 28.0 26.1 25.9 29.1 29.9 29.7 30.1 remark: f'cd= compressive strength from destructive test. f'cn= compressive strength from non-destructive test. the data was presented in the graphical shape as shown in the figures below: figure 8: comparison between destructive and nondestructive test for reference mix and length 1cm al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 395 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 9: comparison between destructive and nondestructive test for the length 2cm figure 10: comparison between destructive and nondestructive test for the length 3cm it can be seen that, there were a big proximity in results between strength obtained from destructive and non-destructive test. the results show, it can have used upv to estimate the compressive strength of concrete contain pet by modified the proposal formulas according to mention above. this is a very good indicator to use waste bottle water in concrete. 6. conclusion and recommendatio to evaluate the concrete strength by using upv test, it must follow the following rule: upv should be greater than 3.5km/sec otherwise the concrete considered unsuitable and weak. the proposal equation to calculate strength of hardened concrete by using upv was according to the ratio of adding as mentioned above. therefore, there is no exceptional relationship can be recognized to cover all concrete specimens. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 396 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. also, the results of this study show that the ratio (1%) for length (3 cm) gives the closest result between the compression strength calculated from destructive and non-destructive test to clarify the accuracy of the ultrasonic equation test because the correlation factor (r) is equal 0.94. this beyond to the following: • this ratio in this length gives homogeneity components of the mixture. this helps to fill the voids without discontinues waves. • the edge of the fibre in form of zigzag give strong bond between the fiber and the mixture without segregation in components of it. this also gives the waves that are transferred continuously without interruptions. for future study, the following point are recommended: • develop this study, by increased the number of samples to achieve the accuracy of the ultrasonic equation test for this type of concrete. • used indirect test method instead of method used in this study to understand their effect on the results. • chang the water cement ratio and increased the ratio of adding plastic as a ratio of the cement weight references 1. ammash, h. k., hemzah, s. a., & jasim, r. (2017). effect of using plastic waste on mechanical properties of concrete. menoufia university, faculty of engineering. ninth conference of sustainable environmental development. 2. al-nu’man, b. s., aziz, b. r., abdulla, s. a., & khaleel, s. e. (2015). compressive strength formula for concrete using ultrasonic pulse velocity. international journal of engineering trends and technology (ijett). 26(1):8-13. 3. benosman, a. s., taïbi, h., mouli, m., senhadji, y., & bahlouli, i. (2016) destructive and nondestructive tests of pet-mortar composites: characterization by tg/dtg analysis. communication science & technology, 16: 89-99. 4. gül, r., demirboğa, r., & güvercin, t. (2006). compressive strength and ultrasound pulse velocity of mineral admixtured mortars. indian journal of engineering and material sciences, 13:18–24. 5. iraqi specification ios 45 – 1984. 6. iraqi specification, no.5,1984, portland cement. 7. lorenzi, a., tisbierek, f. t., & silva, l. c. p. (2007, october). ultrasonic pulse velocity análysis in concrete specimens. in iv conferencia panamericana de end, buenos aires. 8. rajakumar, i., senthilkumar, g., kumar, m. a., balaji, r., & yuvaraju, n. (2016). non destructive analysis on fiber reinforced concrete using waste plastic fiber. international journal of applied science and engineering research, 5(1):1-9. 9. safinia, s. and alkalbani,a. (2016) use of recycled plastic water bottles in concrete blocks, in procedia engineering, volume 164, pp 214-221. article al-qadisiyah journal for engineering sciences 12 (2019) 135–143 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)781706291. e-mail address: fatinashoor80@gmail.com (fatin a. ashoor) https://doi.org/10.30772/qjes.v12i3.603 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. pellet softening process for the removal of the groundwater hardness; modelling and experimentation fatin a. ashoor a*, amer d. zmat a and muthanna h. aldahhan b a department of chemical engineering, university of al-qadisiyah, al-qadisiyah, iraq. b multiphase reactors and applications laboratory mreal, department of chemical and biochemical engineering, missouri university of science and technology, rolla, mo 65409-1230, usa a r t i c l e i n f o article history: received 24 july 2019 received in revised form 04 september 2019 accepted 12 september 2019 keywords: pellet reactor groundwater softening water hardness removal crystillization a b s t r a c t a lab scale pellet reactor (pr) was designed and fabricated to carry out extensive investigations on the removal efficiency of the hardness of groundwater. the groundwater of 2200 – 2600 mg/l hardness was collected from abdulla ibnalhassan wells area located at the west desert of al-shinafiyah district (70 km to the southwest of al-dewaniyah city, iraq). both hydrodynamic parameters of the pellet reactor (porosity and fluidized bed height) and the parameters of calcium carbonate crystallization process (calcium carbonate equilibrium, pellet size, and density) were modeled and compared with the experimental results of the lab scale pellet reactor. the comparison showed that fair agreement between modeled and measured results was observed. the removal efficiency of both calcium and magnesium ions were 62.5-99% and 83-99% respectively. the removal efficiency was found to be strongly dependent on ph and the ratio of naoh solution flow rate to the groundwater flow rate in the pellet reactor. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction pellet reactor (pr) is increasingly used to remove the hardness of groundwater. pr is favored over other softening processes of groundwater due to its low produced sludge, low capital cost, and low maintenance. the main reactions of groundwater softening are shown below [1]; 2 2 3 3 2 2 3 3 2 2 2 2 naoh ca h co caco na h o naoh ca hco na caco h o                pr is simply a cylindrical column filled to a certain depth with a seeding material (sand particles) to crystalize ca+2 ions and form calcium carbonate on its surface [2]. the literature presents many research articles that cover most important aspects of groundwater softening process and pr role [3]. the reactor is firstly filled with granular materials such as sand and quartz. the hard water and softening agent are pumped to the reactor at suitable flow rates to fluidize sand granules and stimulate crystallization of caco3 [4]. crystallization of caco3 on the surfaces of sand particles, in a pellet reactor, can be divided into two stages: nucleation and growth up [5]. nucleation may be described as caco3 crystals formation. growth up is the process in which caco3 crystals crystallize at the surface of sand or quartz granules in the form of layers [6]. mahvi et al. [7] successfully modeled the hydrodynamics and growth rate of crystals of a softening lab scale fluidized bed reactor. he used two-step crystal growth model rather http://qu.edu.iq/ https://doi.org/10.30772/qjes.v00i0 136 fatin .a.ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 than the over-all model. however, utilizing the two-step growth model suffers the lack of the surface-reaction order, and a lean fluidized bed reactor was proposed to include the surface-reaction order. the crystal growth process of low soluble salts seems more complicated than that of soluble salts. then, a comparison between crystal growth kinetics of low soluble salts and the lean fluidized -bed crystallizers was demonstrated. as a consequence, the two-step growth model was found to be convenient for the assessment of crystal growth rates in the design of a liquid fluidized bed reactor [8]. schagen, et al. [9] successfully simulated the pellet reactor and showed the effect of operational parameters (particle size and height of fluidized bed) on the removal efficiencies of the total hardness, calcium ions, and magnesium ions. they observed that maintaining the particle size, the reflux ratio, and the flow rates at optimum values can improve the pellet reactor performance. schagen, et al. [10] (explained through a mathematical model the relationship between the size of the discharged pellets and the saturation rate of caco3 in the treated water. they found that using smaller particle size of seeding materials led to a significant decrease in the saturation rate of caco3 in treated water and improved the pellet reactor performance. schagen, et al. [11] observed that the growth process of crystals of weakly soluble salts looks more intricate than that of high soluble salts. as a result, the two-step growth model was found to be suitable to simulate the rate of crystal growth in fluidized -bed reactor. hu, et al. [12] developed a new mathematical model to study the effect of superficial velocity, particle size, and supersaturation on the rate of pellet particle growth and the fixed bed height growth rate. the study showed a linear relationship between the rate of particle growth and both superficial velocity and supersaturation. the present research aims to study the removal efficiency of total hardness and the modeling of the pellet reactor which is composed of two parts; the first part includes the fluidization and fluidized bed hydrodynamics, while the second part is related to the crystallization process of caco3 on the surfaces of seeding sand particles. the first part aims to model the relation between porosity, pellet diameter, and water velocity. the second part aims to model the crystallization of caco3 as a shift in the equilibrium between the soluble and solid states of calcium. 2. materials and experimental procedure 2.1. materials 2.1.1. groundwater 800 liters of groundwater were collected from well(5) (area of study shown in figure (1)) located in abdulla ibnalhassan area – ash shinafiyah district which is located 70 km to the south-west of ad diwaniyah city, iraq. the depth of well is 75 m. calcium ion concentration, ph and electrical conductivity of groundwater are shown in table (1). table 1. groundwater characteristics parameter value method model ph 7-10.3 ph meter sd300ph e.c (µs/cm) 5380 ec meter cond7110 ca+2 (mg/l) 496664 titration ----------- 2.1.2. seeding materials sand with a particle size of 0.426 2 mm was used as a seeding material to crystalize caco3 on its surfaces. the density of the sand was 1.431 g/cm 3. sand weight was measured before and after each experiment to determine the crystalized caco3 on the surfaces of sand particles. nomenclature dg average diameter of sand grain (m) dg1 average diameter of sand grain , type 1 ( m) dg2 average diameter of sand grain , type 2 ( m) dp average diameter of calcite pellet (m) dp1 average diameter of calcite pellet ,type 1 ( m) dp2 average diameter of calcite pellet ,type 2 (m) reh hydraulic reynolds number sc schmidt number sh sherwood number si saturation index is ionic strength (mmol/l) fw flow of water (l/s) fn flow of naoh solution ( l/s) g gravitational acceleration (m/s2) k crystallization kinetics (l m s−1 mmol−1) ks solubility product (mmol2/l2) kt reaction rate (l m s−1 mmol−1) kt20 reaction rate at 20◦c (l m s−1 mmol−1 ) kf transport rate of supersaturated water to the pellet surface ( l m s−1 mmol−1) δxo fixed bed height m δx fluidized bed height (m) p bed porosity po fixed bed porosity mc total mass of attached caco3 (kg) mc1 mass of attached caco3 of the first sand type (kg) mc mass of attached caco3 of the second sand type ( kg) y1 volume fraction of sand grain , type 1 y2 volume fraction of sand grain , type 2 mc caco3 molecular weight ( g/mmol) ac cross section area of reactor (m2) n number of grains t water temperature ( oc) [ca+2]o initial calcium concentration of groundwater ( mmol/ l) [ca+2]m modeled calcium concentration of treated groundwater (mmol/ l) [ca+2]e measured calcium concentration of treated groundwater (mmol/ l) t time ( s) df diffusion coeffient of groundwater (m2/s) s specific surface area of calcite pellets (m2/m3) c crystallization rate ( mmol l−1 s−1) greek symbols ѳ valency of ion ν kinematic viscosity of groundwater ( m2/s) ρg density of seeding material ( kg/m3) ρc density of caco3 (kg/m 3) ρp average density of calcite pellets (kg/m3) ρp1 density of the first type of calcite pellets (kg/m 3) ρp2 density of the second type of calcite ( kg/m 3) ρw density of groundwater ( kg/m3) fatin a. ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 137 figure 1: the area of study well 5 locations 2.1.3. naoh granules naoh granules from sigma-aldrich were used to prepare 0.625 molarity (2.5% mass concentration) naoh solution. the characteristics of naoh granules are shown in table (2). table 2, the characteristics of naoh granules 2.13 g/cm3 density 40 gm/mole molecular weight 318 °c (604 °f; 591 k) melting point 1,388 °c (2,530 °f; 1,661 k) boiling point 2.2. experimental procedure 2.2.1. description of the lab scale pellet reactor (pr) the lab scale pr shown in figures (2, 3) was used for removing total hardness, calcium ions, and magnesium ions for groundwater. it is simply a fluidized bed column made from plexiglas with an inner diameter of 6 cm and 170 cm height. the groundwater was fed (injected) through three nozzles mounted at the bottom plate of the column, while the naoh solution was fed (injected) through one nozzle located at the center of the bottom plate. nozzles details are schematically shown in figure (4). the pr was equipped with two rotameters to measure both groundwater and naoh solution flowrates. water rotameter measuring range is (25-250) l/hr and naoh solution rotameter are in the range of (6-30) l/hr. a sand filter with 12 cm outer diameter and 27 cm height was installed at the outlet of the pr to capture suspended materials. two pressure measuring devices (0.0 – 6.0 bars) were installed on the lines of groundwater and naoh solution supply for measuring pressure head of both supply lines. three plastic tanks were used for storing groundwater, naoh solution and treated water. 1.575 kg of a seeding material was used to fill a height of 42 cm of the fbr. the seeding material (sand) was brought from local sources. figure 2: photo of the pr setup figure 3: schematic representation of water softening in pr figure 4: schematic structure of the nozzle 138 fatin .a.ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 3. hydrodynamics of the pr (ergun model) 3.1. porosity ergun model is widely utilized to calculate the porosity of the fluidized bed. porosity is fundamentally calculated depending on balancing the pressure gradient across the fluidized bed, the mass of the pellets, and the acting drag force of the water on the calcite pellets[13]. the pressure gradient is expressed as: 𝛥𝑝 𝛥𝐿 = (𝜌𝑃 − 𝜌𝑊 ). (1 − 𝑃). 𝑔 (1) the pressure gradient caused by the acting drag force of the water on the calcite pellets is represented by equation (2). 𝛥𝑃 𝛥𝐿 = 3 2 𝐶𝑤1 𝜐2 2 (1 − 𝑝) 𝑝3 𝜌𝑤 𝑑𝑝 (2) 𝐶𝑤1 is the drag coefficient which is expressed in terms of the hydraulic reynolds number (reh). 𝐶𝑤1 = 2.3 + 150 𝑅𝑒ℎ (3) where, 𝑅𝑒ℎis the particle reynolds number, expressed using the following empirical equation [14]: 𝑅𝑒ℎ = 2 3 𝜐 𝑑𝑝 (1 − 𝑝)𝜈 (4) for the range of 𝑅𝑒ℎ between (5 -100), cw1 is expressed in equation (5). 𝐶𝑤1 ≈ 125 𝑅𝑒ℎ 0.8 (5) finally, the general form of the porosity equation is: 𝑝3 (1 − 𝑝)0.8 = 130 𝜐1.2 𝑔 𝜈0.8 𝑑𝑝 1.8 𝜌𝑤 𝜌𝑝−𝜌𝑤 (6) this equation has generally been utilized in most researches to find the porosity of the pellet softening column [14-16]. 3.1.1. the height of fluidized bed the height of the fluidized zone of sand particle in the pellet reactor is calculated as shown in equation (7) [17]: 𝛥𝑥 = ( 𝑚𝑐 𝜌𝑐 + 𝑚𝑔 𝜌𝑔 ) (1 − 𝑝)−1 𝐴𝑠 −1 (7) 3.2. crystallization of caco3 modelling 3.2.1. 3 pellet size and density the pellet diameter relies on the accumulated mass of calcite (caco3) on the surface of sand particles. the pellet size is determined using the following equation [17]: 𝑑𝑝 = 𝑑𝑔 √1 + 𝜌𝑔 𝜌𝑐 𝑚𝑐 𝑚𝑔 3 (8) the calcite pellets density is represented by the mass of calcite (caco3) on sand surface (𝑚𝑐) and the mass of the sand particle (𝑚𝑔), as follows [17]: 𝜌𝑝 = (𝑚𝑐 + 𝑚𝑔 )( 𝑚𝑐 𝜌𝑐 + 𝑚𝑔 𝜌𝑔 )−1 (9) two types of sand have been used, so the pellet size and density of the two types are: afor dg1 =2×10 -3 m 𝑚𝑐 1 = 𝑚𝑐 × 𝑦1 (10) 𝑦1 = (𝑚𝑔1 /𝜌𝑔1) (𝑚𝑔 /𝜌𝑔) (11) bfor dg2 =0.5×10 -3 m 𝑚𝑐 2 = 𝑚𝑐 × 𝑦2 (12) 𝑦2 = (𝑚𝑔2 /𝜌𝑔2) (𝑚𝑔 /𝜌𝑔) (13) the average pellet size and density is calculated as follow: ρp= 0.29 ×ρp1 at 2mm + 0.71× ρp2 at 0.5 mm (14) dp= 0.29 ×dp1 at 2mm + 0.71× dp2 at 0.5 mm (15) 3.2.2. the equilibrium of calcium carbonates (caco3) calcium carbonate crystallization occurs when the solid and soluble calcium carbonate (caco3) are in equilibrium [18]. ca+2 + co3-2 ks caco3 (16) the activity coefficient (f) relies on the water ionic strength (is) and it's represented by the following equation: 𝐿𝑜𝑔 (𝑓) = ѳ2. −0.5√𝐼𝑆 √1000 + √𝐼𝑆 = ─0.0002 𝐼𝑆 (17) the ionic power determines the ionic strength of solutions by the concentration of ions in the solution. when compounds dissolved in water, they are divided into ions and their ionic strength is expressed by using equation (18) [19]. iscaco3= 1 2 [ [ca+2] × (valency of ca+2 ion) 2 + [ [co3-2] × (valency of co3-2 ion) 2] (18) the supersaturation of calcium carbonate (caco3) in water is based on two parameters. the saturation index (si) and ph which can be represented as the ph offset (phs) when the actual calcium ion concentration (ca +2) is in fatin a. ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 139 a balance with the carbonate (co3 −2 ).the crystallization driving force is determined by the saturation index (si). the two indicators are highly attached and utilized for determining the crystallization process performance. the saturation index and the ph offset are determined using equations (19) and (20) respectively. 𝑆𝐼 = 𝑙𝑜𝑔 [𝐶𝑎+2] × [𝐶𝑂3 −2] 𝐾𝑠 (19) phs = phsi (20) the change in calcium concentration in equation (21) is determined by the supersaturation of calcium carbonate, the calcite pellets specific surface (s), and the crystallization kinetics (k) [20]. 𝑑[𝐶𝑎+2] 𝑑𝑡 = 𝐾 . 𝑆 . ([𝐶𝑎+2][𝐶𝑂3 −2] − 𝑘𝑠 𝑓8 ) (21) where, ks is the solubility product, which is a function to concentrations of calcium and carbonate, and it is calculated by equation (22). 𝐾𝑠 = [𝐶𝑎+2][𝐶𝑂3 −2] (22) then the modeled calcium concentration as follows: 𝑙𝑛 [𝐶𝑎+2]𝑚 = ─ 0.175 . 𝐾 . 𝑆 . [𝐶𝑎+2]𝑜[𝐶𝑂3 −2]. 𝑡 + 2.5 (23) equation (24) is used to calculate the specific surface of calcite pellets (s) as a function of bed porosity (p) and diameter of pellets (dp). 𝑆 = 6(1 − 𝑝) 𝑑𝑝 (24) the supersaturated water with calcite that transport to seeding material surface relies on the temperature and water flow, the crystallization constant is calculated from equation (25)[21]. 𝐾 = 𝐾𝑓 . 𝐾𝑇 𝐾𝑓 + 𝐾𝑇 (25) the water flow pattern between calcite pellets relies on the schmidt number (sc), and the reynolds number of the water flow in the bed (reh). equation (27) represents the sherwood number (sh)[22] . 𝑠𝑐 = 𝜈 𝐷𝑓 (26) sh=0.66reh0.5sc0.33 (27) equation (28) is used to determine the coefficient of transportation (kf). 𝐾𝑓 = 𝑆ℎ . 𝐷𝑓 . 𝑑𝑝 (28) the temperature dependency constant (kt) is calculated by the following equation [22]: kt=1.053(t-20).kt20 (29) the crystallization rate: 𝐶 = ─ 𝑑[𝐶𝑎+2] 𝑑𝑡 = (0.175 . 𝐾 . 𝑆. [𝐶𝑎+2][𝐶𝑂3 −2]) (30) the mass of crystallized calcium carbonate (caco3) can be determined by equation (32) using pellet diameter from equation (15) and the number of sand particles from equation (31). the number of sand particles is determined using the following equation [23]: 𝑁 = 𝐴𝑠. 𝛥𝑥𝑜 . (1 − 𝑝0) 1 6 𝜋 𝑑𝑔 3 (31) therefore, the crystallized mass of calcium carbonate can be found as: 𝑚𝑐 = 𝑁. ( 1 6 𝜋 𝑑𝑝 3 ─ 1 6 𝜋 𝑑𝑔 3 ) . 𝜌𝑐 (32) 3.3. modeling work there are two main models that are commonly used to model pellet softening reactors. the first model is ergun model (1952)[13 ] which is the exerted forces on the pellets in the reactor, and the second model is zaki model (1954) [14 ]which is based on an expansion formula, because zaki model is preferred for full scale pr experiment, ergun model was adopted in this chapter for lab scale pr experiments. 4. results and discussions 4.1. effect of water flow rate on the fluidized bed height and bed porosity figures 5, 6, and 7 show that the bed porosity is strongly dependent on the height of the fluidized bed. the porosity was in the range of (0.442 – 0.454) for the bed height of 0.71-0.73 at a flow rate of water of 25 l/hr., (0.2 – 0.6) for the bed height of 0.4-0.9 at water flow rate of 37.5 l/hr., and (0.5630.565) for the bed height of 0.91-0.93 at water flow rate of 50 l/hr. the value of the water flow rate was 37.5 l/hr. and has many effects on the bed height as a result of interaction took place between the two sand types in comparison with both water flow rates (25, 50 l/hr.) and consequently is reflected in a wide range of porosity variation. for the 25 l/hr. flow rate, the fine particles were dominated bed expansion region while coarse particles were packed together. for the 37.5 l/hr. flow rate, the coarse particles start expanding and mixed with the fine particles, so that a wide range of expanded bed was noticed. and finally for the 50 l/hr. flow rate, the bed expansion was maximized and both particle types (fine and coarse) were fluidized together. however, increasing the water flow rate (fw) led to increase in the fluidized bed height, then resulted in an increase of bed porosity. this conclusion agrees with the work of kramer et al. [24], as they demonstrated that increasing of fluidized bed height from (1-4) m increases the bed porosity from 0.72 to 0.85 at water flowrate (fw= 500 m3/h), and increasing fluidized bed height from (1-4) m increases the bed porosity from 0.52 to 0.75 at water flowrate (fw= 300 m3/h). 140 fatin .a.ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 figure 5: bed porosity (p) versus fluidized bed height at water flow rate (fw) = 25 l/h figure 6: bed porosity (p) versus fluidized bed height at water flow rate (fw) = 37.5 l/h figure 7: bed porosity (p) versus fluidized bed height at water flow rate (fw) = 50 l/h 4.2. effect of flow rate of water on the fluidized bed height and the pellet diameter and density figures 8,9, and 10 show the effect of water flow rate on the expansion of the bed (bed height) and consequently on the pellet diameter. as the bed height increases, the pellet diameter decreases due to higher water upward velocity which causes a higher rate of erosion of the pellet surface. however, for water flow rate of 50 l/hr., the pellet diameter decreased from 0.937 – 0.936 when the bed height increased from 0.81 – 0.85, which is lower than the bed height for flow rates 25, and 37.5 l/hr. this may be due to a probable homogeneity of bed expansion at higher water velocities. figure 8: pellet diameter versus fluidized bed height at water flow rate (fw) = 25 l/h figure 9: pellet diameter versus fluidized bed height at water flow rate (fw) = 37.5 l/h figure 10: pellet diameter versus fluidized bed height at water flow rate (fw)=50 l/h figures 11, 12, and 13 reflect the effect of bed height on the pellet density for the water flow rates 25, 37.5, 50 l/hr. respectively. the density of pellets decreased as bed height increased. this agrees with hu et al. [25] studies which showed that the highest dense pellets are settled at the bottom of the reactor while the least dense pellets are fluidized at the upper part of the reactor. 0.44 0.442 0.444 0.446 0.448 0.45 0.452 0.454 0.456 0.705 0.71 0.715 0.72 0.725 0.73 0.735 b e d p o ro si ty fluidized bed heiight (m) 0.5155 0.516 0.5165 0.517 0.5175 0.518 0.5185 0.8 0.82 0.84 0.86 b e d p o ro si ty fluidized bed heiight (m) 0.5625 0.563 0.5635 0.564 0.5645 0.565 0.5655 0.9 0.91 0.92 0.93 0.94 b e d p o ro si ty fluidized bed heiight (m) 0.93655 0.9366 0.93665 0.9367 0.93675 0.9368 0.93685 0.9369 0.93695 0.937 0.8 0.82 0.84 0.86p e ll e t d ia m e te r (m m ) fluidized bed height (m) 0.9365 0.9366 0.9367 0.9368 0.9369 0.937 0.9371 0.9 0.91 0.92 0.93 0.94 p e ll e t d ia m e te r (m m ) fluidized bed height (m) 0.93615 0.9362 0.93625 0.9363 0.93635 0.9364 0.7 0.71 0.72 0.73 0.74p e ll e t d ia m e te r (m m ) fluidized bed height (m) fatin a. ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 141 figure 11: pellet density versus fluidized bed height at water flow rate (fw) = 25 l/h figure 12: pellet density versus fluidized bed height at water flow rate (fw) = 37.5 l/h figure 13: pellet density versus fluidized bed height at water flow rate (fw) = 50 l/h 4.3. comparison between modeled and measured calcium concentrations figures 14, 15, and 16 show fair agreement between modeled and measured concentrations of ca+2 ions. the 50 l/hr. water flow rate showed better agreement between modeled and measured concentrations. the higher water flow rates demonstrated good mixing of large and fine particles within the expanded (fluidized) bed and better distribution of ca+2 ions. the 25 l/hr. water flow rate reflects the case where large particles were settled at the bottom of the bed and minor expansion of bed was noticed. this can be attributed to a considerable inhomogeneity of ca+2 ions in the expanded bed. figure 17 demonstrates that a good agreement between measured and modeled values of calcium ions concentration was noticed for the nine experiments in this research. figure 14: modeled calcium concentration versus measured calcium concentration at water flow rate (fw) 25 l/hr. figure 15: modeled calcium concentration versus measured calcium concentration at water flow rate (fw) 37.5 l/h figure 16: modeled calcium concentration versus measured calcium concentration at water flow rate (fw) 50 l/hr. figure 17: measured and modeled values of calcium ions concentrations vs. run number 1330 1330.2 1330.4 1330.6 1330.8 1331 1331.2 0.7 0.71 0.72 0.73 0.74 0.75 p e lle t d e n si ty ( kg /m 3 ) fluidized bed height (m) 1331.5 1332 1332.5 1333 1333.5 1334 0.8 0.81 0.82 0.83 0.84 0.85 0.86 p e lle t d e n si ty ( kg /m 3 ) fluidized bed height (m) 1332 1332.5 1333 1333.5 1334 1334.5 0.905 0.91 0.915 0.92 0.925 0.93 0.935p e ll e t d e n si ty ( k g /m 3 ) fluidized bed height (m) [ca+2]m = 0.8759[ca +2]e r² = 0.9456 0.07 0.12 0.17 0.22 0.27 0.32 0.37 0.42 0.09 0.19 0.29 0.39 0.49 m o d e le d c a lc iu m co n ce n tr a io n ( m m o l/ l) measured calcium … [ca+2]m = 0.845[ca +2]e r² = 0.999 0.07 1.07 2.07 3.07 4.07 5.07 0.09 1.09 2.09 3.09 4.09 5.09 m o d e le d c a lc iu m co n ce n tr a io n ( m m o l/ l) measured calcium concentraion (mmol/l) 0 2 4 6 0 1 2 3 4 5 6 7 8 9 10 c a lc u im c o n ce n tr a ti o n (m m o l/ l) run number maesured calcuim concentration [ca+2]m = 0.8074[ca +2]e r² = 0.71620.07 0.08 0.09 0.1 0.11 0.12 0.13 0.14 0.09 0.11 0.13 0.15 0.17 m o d e le d c a lc iu m co n ce n tr a io n ( m m o l/ l) measured calcium concentraion(mmol/l) 142 fatin .a.ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 4.4. comparison between modeled and measured fluidized bed height (m) a fair agreement between modeled and measured fluidized bed height was observed as shown in figure 18. however, higher water flow rate results in better agreement between modeled and measured fluidized bed height. the correlation coefficient of the fitting in figure 18 is 0.94, which indicates well correlated data this agreed with hu, et al. [26] which they compared between modeled and measured fluidized bed height, the correlation coefficient of their study was 0.95. figure 19 shows fair agreement between modeled and measured values of fluidized bed height for the nine experiments in this research work. figure 18: modeled fluidized bed height versus fluidized bed height at water flow rate (fw) 25, 37.5, 50 l/hr. figure 19: measured and modeled values of fluidized bed height (m) vs. run number at water flow rate (fw) 25, 37.5,50 l/hr 4.5. comparison between modeled and measured calcium carbonates mass (kg) deposited on the surfaces of the pellets a fair agreement between modeled and measured mass of calcium carbonates deposited on the surfaces of the pellets was observed as shown in figures 20, 21, and 22. however, higher water flow rate leads to better agreement between modeled and measured mass of calcium carbonates. this also can be attributed to the better homogeneity of fluidized particles of sand in the expanded bed of the pellet reactor. figure 23 shows fair agreement between modeled and measured values of calcium carbonate mass for the nine experiments in this research work. figure 20: modeled mass of calcium carbonate versus measured mass of calcium carbonate at water flow rate (fw) 25 l/hr. figure 21: modeled mass of calcium carbonate versus measured mass of calcium carbonate at water flow rate (fw) 37.5 l/hr. figure 22: modeled mass of calcium carbonate versus measured mass of calcium carbonate at water flow rate (fw) 50 l/hr. figure 23: measured and modeled values of calcium carbonate mass (kg) vs. run number δxmodeled= 0.9489δxmeasured r² = 0.940.65 0.7 0.75 0.8 0.85 0.9 0.95 0.65 0.75 0.85 0.95 1.05 m o d e le d f lu id iz e d b e d r e a ct o r (m ) measured fluidized bed reactor (m) 0.65 0.75 0.85 0.95 1.05 0 1 2 3 4 5 6 7 8 9 f lu id iz e d b e d h e ig h t (m ) run mumber measured fluidized bed height modeled fluidized bed height mcm = 0.8171mce r² = 0.8606 0.0095 0.01 0.0105 0.011 0.0115 0.012 0.011 0.012 0.013 0.014 0.015m o d e le d c a c o 3 m a ss ( k g ) measured caco3mass (kg) mcm= 0.8208mce r² = 0.9141 0.012 0.013 0.014 0.015 0.016 0.017 0.015 0.017 0.019 0.021 m o d e le d c a c o 3 m a ss ( k g ) measured caco3mass (kg) mcm = 0.788mce r² = 0.9977 0.012 0.013 0.014 0.015 0.016 0.017 0.015 0.017 0.019 0.021 0.023 m o d e le d c a c o 3 m a ss ( k g ) measured caco3mass (kg) 0 0.01 0.02 0.03 0 2 4 6 8 10 m e a su re d m a ss o f ca lc u im ca rb o n a te ( k g ) run number measured mass of calcuim carbonate fatin a. ashoor et. al /al-qadisiyah journal for engineering sciences 12 (2019) 135–143 143 5. conclusions very high removal efficiencies of total hardness were obtained when flow rates of the groundwater and naoh solution are properly determined. the obtained results revealed that 78.7 – 99.1% efficiencies can be achieved when the ratio of naoh solution flow rate to the groundwater flow rate ranges from 0.24 to 0.72 with an initial ph of 7-10.3. modeling results of the groundwater softening process using pellet reactor showed that fair agreement between measured and modeled values of the removal efficiency, crystallized mass of calcium carbonates, bed porosity, pellet diameter and density distribution in the expanded (fluidized) bed. the successful modeling of the pellet reactor led to reducing cost of experimentation and may lead to better understanding of groundwater softening processes. references [1] hofman, j. a. m. h., onno kramer, jan peter van der hoek, maarten nederlof, and martijn groenendijk, "twenty years of experience with central softening in netherlands: water quality, environmental benefits, and costs," in international symposium on health aspects of calcium and magnesium in drinking water, pp. 24-26, 2006. 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[26] hu, r. z., huang, t. l., wen, g., & yang, s. y. ,''modelling particle growth of calcium carbonate in a pilot-scale pellet fluidized bed reactor,'' water science and technology: water supply, 17(3), 643651,2017. http://resolver.tudelft.nl/uuid:7ff60173-129b-4e5d-a33f-81390a8704bf al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 63 efficient viscosity evaluation using artificial neural network for epoxy after addition waste natural material afraa hilal kamel assist. lecturer chemical engineering department, university of technology, baghdad, iraq email: a.k_eng@yahoo.com received 31 may 2015 accepted 9 november 2015 abstract artificial neural networks (ann) were used to predict the viscosity of epoxy resin modified by natural waste material (pomegranate peel) powder. this waste material, which has a high pollution capacity for the environment, could be used as an improvement to the properties of a weaken material such as epoxy resin in reservoir engineering computations the viscosity parameter is a very important fluid property. the data is not either reliable or unavailable most of the time; it should be specified in the lab. levenberg-marquardt backpropagation of artificial neural network based model (anns) was evolved to predict the viscosity of modified pomegranate peel powder of epoxy resin. three parameters affecting the viscosity of mixtures based on epoxy resin containing pomegranate peel powder and pure epoxy resin were studied. these are temperature, concentration of pomegranate peel, and shear rate. the viscosity as output was predicted by training the network. a network was built up and trained using experimental information. the effects of temperature (30-50 °c), concentration of pomegranate peel powder (06)wt% and shear rate (4.35-15.95 1/sec) on the epoxy resin were modeled by anns as well. the expected values were in excellent agreement with the measured ones, showing that the developed model is really accurate and has the great ability for predicting the viscosity. the linear regressions r 2 0.9994 and 0. 9998 are the values of the ann viscosity model for training and testing data set, respectively, 2.7175*10 -4 and 1.2441*10 -4 are the values of mean square error respectively. keywords: artificial neural network . viscosity. waste natural material. pomegranate peel. epoxy resin تقييم كفاءة اللزوجة باستخدام الشبكات العصبية لاليبوكسي بعد اضافة مخلفات مادة طبيعية عفراء هالل كامل مدرس مساعد التكنولوجية, قسم الهندسة الكيمياويةالجامعة mailto:a.k_eng@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 63 الخالصة تم استخدام الشبكة العصبية االصطناعية للتنبؤ بلزوجة راتنج االيبوكسي عن طريق اضافة مسحوق احد مخلفات المواد وهي ها هنا لتحسين قشور الرمان. تعتبر هذه المخلفات من الملوثات البيئية ذات السعة الكبيرة في تلويث البيئة ولكن يعد استخدام بعض الخواص الضعيفة لراتنج االيبوكسي ويعتبر معيار اللزوجة هو عامل انسياب مهم في الحسابات الهندسية. تحسب اللزوجة في المختبرات ولكن معظم البيانات تكون غير مناسبة اومتوفرة. لذا تم تطوير شبكة عصبية اصطناعية الجل حيث توجد ثالث عوامل تؤثر على لزوجة المزيج المكون من راتنج االيبوكسي المحتوي على التنبؤ باللزوجة لراتنجات االيبوكسي مسحوق قشور الرمان وهي درجة الحرارة , تركيز القشور و معدل اجهاد القص. (.outputوتم تدريب الشبكة ليتم التنبؤ باللزوجة كناتج خارج ) (input)تعتبر هذه العوامل الثالثة هي المتغير الداخل , تركيز قشور (c° 50-30)تم تدريب الشبكة باالعتماد على النتائج العملية وحيث ان حدود المتغيرات كدرجة الحرارة هي على راتنج االيبوكسي. (sec/1 15.95-4.35)( واجهاد القص %wt (3-0الرمان القيم العملية والذي يشير الى ان الموديل تم بناء موديل للشبكة العصبية ووجدت ان القيم المتنبأ بها على تطابق ممتاز مع المطور دقيق جدا" وله قابلية كبيرة للتنبؤ باللزوجة. على التوالي. 0.9998و 0.9994بنظام التدريب واالختبار بقيمةr2 ان قيمة التقريب الخطي مي التدريب واالختبار على لنظا 4-10*1.2441و 4-10*2.7175وان مقدار قيمة التقريب الخطي مربع الخطأ بقيمة التوالي. اللزوجة . مخلفات المواد الطبيعية . قشور الرمان . راتنج االيبوكسي .العصبية االصطناعية . بكة الش الكلمات المرشدة: 1. introduction one of the most important computational tools is the artificial neural network (ann) that allows overcoming the difficulty of calculating the difficult and highly nonlinear relationships among model parameters through self-organization, pattern recognition and functional approximation. the structure and internal functions of the biological brain is simulated by ann. unlike conventional models, the model structure between input and output variables does not assumed by ann. the database was provided by training the network to generate the model. the problems were solved by ann using creating parallel networks and the training/learning of those networks, rather than by a specific programming scheme based on well-defined rules or assumptions [1]. ann has the ability to learn from the pattern acquainted before. the network is trained with adequate number of sample data sets and then it can make guesses when new input data sets of the similar pattern are given. hence, ann is successfully used in many industrial areas in addition to research areas for the prediction of different complex parameters from simple input parameters[2]. one of the most popular of polymers materials is the epoxy resin which has been widely used as protection system of heterogeneous composites in many structures because of its prominent process ability, good electrical insulating properties, distinguished thermal resistance, strong adhesion, and affinity to heterogeneous material with a higher mechanical properties under heavier loading [3]. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 63 it is very important reducing the cost in the modern industries also declining the pollution which represents a big harmfulness to the environment. nowadays, the waste materials are used increasingly in reinforcement and formation new materials. the necessity for materials that are non-toxic to the human body and have appropriate characteristics for specific purposes is ever increasing because of the lack of resources and increasing levels of environmental contamination. due to the inexpensive and ability to reduce the environmental contamination caused by the characteristic biodegradability, the natural substances as reinforcing fillers are used for the production of composites, these composites are important in resolving the future environmental problems [4]. in polymer composites the filler type is very important [5].because strong astringency and making them a popular remedy throughout the world, the waste natural materials (pomegranate peels) are exploited in traditional uses [6]. new composites are being developed in the continual quest to improve material performances [7]. the rheological properties of epoxy resin must be understood in order to improve the pumping and transports in the design [8]. the viscosity is defined as resistance to flow therefore it is one of the most important theological characteristics of a fluid [9] and it is the most important thermophysical properties of fluids, especially in thermal applications where heat transfer and fluid flow take place. in industrial applications the changes in viscosity attributes effect the convective heat transfer coefficients in addition to the pumping power required. therefore, accurate information on the viscosity attributes of fluids is necessary [10]. the behavior of epoxy can be expected by different conditions such as the well-known dependence of viscosity on the shear rate, temperature, concentration of additive and other parameters. therefore, the values of viscosity epoxy are not fine predicted and it is hard to define a concise relationship between the factors (variables), or the problem is too intricate to be described mathematically [11]. increasingly, ann is starting considered to develop models from data in their ability to improve the modeling accuracy and to improve the process modeling eventually [12]. the works experimentally and theoretically have been devoted to the viscosity of fluids by using anns that studied by several researchers [1, 9-11, 13-16,19]. the purpose of this paper is to study the variation of viscosity of epoxy resin by the addition of waste natural material (pomegranate peel) powder at different concentrations, temperatures and shear rates. also compare the viscosity of epoxy resin predicting by using levenberg-marquardt backpropagation of artificial neural networks with experimental values. 2.materials and methods 2.1. experimental procedure in this study, epoxy resin was used as a matrix polymer. the epoxy resin type epikote828 were provided by shell company. properties of epoxy resin are given in table (1). the type of reinforcing filler of waste natural material was pomegranate peel powder used in this research. the pomegranate peel was collected and crashed by using a ball milling process, the specification of it (250 rpm). the viscosities of the resin systems containing (0, 1, 2 and 3) wt % of powder of pomegranate peel were determined by using a rotational brookfield viscometer model dv-ii-pro at different temperatures (30, 40 and 50 °c) and six different shear rates (4.35, 6.67, 8.99, 11.31, 13.63 and 15.95 s -1 ). al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 63 2.2. artificial neural networks (ann) in this study, ann is used to predict viscosities of epoxy systems. a computer program was performed under matlab 7.10 software. the categories divided into two parts for the results of experimental data the first was used for nn training while the other part was employed for network testing, and finally train the ann that is built according to the specified data and calculate the performance of training results by using mean square error (mse)and the linear regressions (r 2 ). the mse and r 2 were computed using the following equations (1,2) [17,18]: ∑ ( ) (1) [ ∑ ( ) ∑ ( ) ] (2) where t is a target value, o is an output value, and n is a pattern. the network having minimum mse and maximum r 2 is chosen as the best ann models. for the epoxy system, 60 of 72 data are used for training the ann and 12 data are used for testing purposes with sigmoid hidden neurons and linear output neurons, three layers feed forward network is used as the network. levenberg-marquardt backpropagation training algorithm is used to train the network. the layers were used one input layer, one hidden layer, and one output layer. the hidden layer performs the computations in the network. table (2) clears the range of the input parameters in ann. three parameters affecting the viscosity were considered as inputs, including concentration of pomegranate peel, the temperature, and shear rate. the network was then trained so that to predict the viscosity as outputs. the present study of neural network architecture is given in fig.(1).in the feed forward networks, neurons are arranged from input towards output in order layers and transmission from one layer to another is only available for the next layer. the data which are acquired moved first to the input layer then to the hidden layer and lastly to the output layer where they are processed and the results are joined to the outer world. it has been verified that a three layers feed forward ann can approximate any continuous function at the wanted accuracy level provided that an adequate number of neurons are included in the hidden layer. eventually, and in order to support the neural network to deal effectively with the data, all the input data were normalized to the range of (0-1). 3. results and discussion the particle size of pomegranate peel in this research was less than (2 µm), as verified by scanning electron microscope (sem), model tescan vega 3 sb which was employed to determine the morphology of the samples at 20kv. the sem micrograph is shown in fig.(2). 3.1. effect of parameters on viscosity 3.1.1. effect of additive pomegranate peel powder on viscosity the viscosity variation with increasing concentration of pomegranate peel powder in the epoxy resin was studied for different concentration (0-3) wt% at different temperatures. this will help us in determining the optimum fluid viscosity for fluid pump ability necessary for efficient flow at different conditions of concentrations and temperature. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 04 fig.(3) shows viscosity change with shear rate for different wt% of pomegranate peel powder at fixed temperature (30 o c). it is clearly seen that at this temperature the addition of pomegranate peel powder in different wt% has no remarkable effect on reduction of viscosity of epoxy resin. in fact the best reduction in viscosity occurs without any addition of pomegranate peel powder. fig.(4 and 5) illustrate the variation of viscosity with shear rate at various wt% of pomegranate peel powder at 40 o c and 50 o c respectively. fig.(4) demonstrates that when the addition of pomegranate peel powder is 2wt% gives the better reduction in viscosity of epoxy resin at 40 o c while, fig.(5) shows that better reduction in viscosity occurs after the addition 3wt% of pomegranate peel powder at 50 o c which indicate that addition of pomegranate peel powder to epoxy resin could be the a good option for the viscosity reduction with temperature increase. this behavior is in good agreement with results obtained by stabik [19]. 3.1.2. effect of temperature on viscosity fig.(6,7,8 and 9) show the relation between viscosities of epoxy resin unmodified – modified with different temperatures (30, 40 and 50) o c versus shear rate at different amounts of pomegranate peel (0-3) wt%. as can be seen in the figures the viscosity decreased with increasing temperature for all concentrations. it is the result of generally observed polymers viscosity decrease with temperature increase. actually known is arrhenius law for temperature dependence of viscosity [19]: ( ) [ ( )] (3) where: viscosity in reference temperature, e – activation temperature, r – gaseous constant, tr– reference temperature. these results are in good agreement with the results get from stabik [19]. 3.1.3. effect of shear rate on viscosity in general of all fig.(3,4,5,6,7,8 and 9) illustrated the viscosity of epoxy resin modified by pomegranate peel powder used in this work increased as the shear rate is increased. this behavior occurs because as in some substances when the relationship between viscosity and shear rate is proportional that is called shear-thickening [20]. 3.2. artificial neural network model a three layers ann with a tangent sigmoid transfer function (tansig) at hidden layer and a linear transfer function (purelin) at output layer were used. feed forward levenberg-marquardt backpropagation network was used. the input layer has 3 neurons (temperature, concentration of pomegranate peel, and shear rate) , one hidden layer has 9 neurons and output layer has one neuron (viscosity). as shown in fig.10 (a, b), the r 2 values of the nn viscosity model are 0.9994 and 0.9998 for training and testing data sets respectively. their mean square error (mse) values are 2.7175*10 -4 and 1.2441*10 -4 . fig.(10) shows that the ann displays an accurate prediction based al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 04 on a high r 2 value and a low mse value. as a result, the developed nn viscosity model successfully improves the prediction possibility of viscosity value of epoxy modified pomegranate peel powder at various conditions. 4. conclusions 1. viscosity variation with shear rate for different composition of pomegranate peel powder at different temperatures, the addition of pomegranate peel powder to the epoxy resin could be a good option for the viscosity reduction with an increase in temperature. 2. viscosity decreased with increasing temperature for all concentrations. 3. viscosity of epoxy resin modified by pomegranate peel powder increased as the shear rate is increased. 4. anns were used to predict the viscosity of epoxy resin modified by natural waste material (pomegranate peel) powder. the expected values are in excellent agreement with the measured ones, showing that the developed model is very accurate and has a greater aptitude for expecting the viscosity. references [1] shahriar, a., and nehdi, m., "modeling rheological properties of oil well cement slurries using multiple regression analysis and artificial neural networks", 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[19] stabik, j., dybowska, a., szczepanik, m., and suchon, l., "viscosity measurements of epoxy resin filled with ferrite powders", journal of archives of materials science and engineering, vol.38, pp.34-40, 2009. [20] jiang, b., keffer, d. j., edwards, b. j., and allred j. n., " modeling shear thickening in dilute polymer solutions: temperature, concentration, and molecular weight dependencies", journal of applied polymer science, vol. 90, pp.2997–3011, 2003. http://www.scielo.br/scielo.php?script=sci_serial&pid=1516-1439&lng=en&nrm=iso http://www.sciencedirect.com/science/article/pii/s0735193313000365 http://www.sciencedirect.com/science/article/pii/s0735193313000365 http://www.sciencedirect.com/science/article/pii/s0735193313000365 http://www.sciencedirect.com/science/journal/07351933 http://www.sciencedirect.com/science/article/pii/s0950061809001160 http://www.sciencedirect.com/science/journal/09500618 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 06 table (1): epikote828 properties. typical properties value epoxide equivalent weight 434430 viscosity, at 25 °c, poise 444454 color, gardner 1 max physical form clear liquid density, g/ml at 25 °c (77 °f) 4143 flash point no flash at 249°c (480 °f) vapor pressure, mm hg at 77 °c (170°f) 4146 refractive index at 25 °c (77 °f) 41536 table (2): the range of the input parameters in ann. inputs range concentration of pomegranate peels wt% 0-3 temperature ( o c) 30-50 shear rate (1/s) 4.35-15.95 figure (1): the system architecture used in the anns models. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 00 figure (2): sem micrograph of pomegranate peel. figure (3): viscosity of epoxy resin modified by pomegranate peel for different concentration vs. shear rate at 30 o c. figure (4): viscosity of epoxy resin modified by pomegranate peel for different concentration vs. shear rate at 40 o c. 0 5000 10000 15000 20000 25000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 30c, 0 wt% 30c, 1 wt% 30c, 2 wt% 30c, 3 wt% 0 5000 10000 15000 20000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 40c, 0 wt% 40c, 1 wt% 40c, 2 wt% 40c, 3 wt% al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 05 figure (5): viscosity of epoxy resin modified by pomegranate peel for different concentration vs. shear rate at 50 o c. figure (6): viscosity of epoxy resin modified by pomegranate peel (0 wt%) versus shear rate at different temperatures. figure (7): viscosity of epoxy resin modified by pomegranate peel (1 wt%) versus shear rate at different temperatures. 0 1000 2000 3000 4000 5000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 50c, 0 wt% 50c, 1 wt% 50c, 2 wt% 50c, 3 wt% 0 2000 4000 6000 8000 10000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 30c, 0 wt% 40c, 0 wt% 50c, 0 wt% 0 5000 10000 15000 20000 25000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 30c, 1 wt% 40c, 1 wt% 50c, 1 wt% al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 03 figure (8): viscosity of epoxy resin modified by pomegranate peel (2 wt%) versus shear rate at different temperatures. figure (9): viscosity of epoxy resin modified by pomegranate peel (3 wt%) versus shear rate at different temperatures. figure (10): the graphical output of the experimental viscosity plotted versus neural network predicted viscosity. 0 5000 10000 15000 20000 25000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 30c, 2 wt% 40c, 2 wt% 50c, 2 wt% 0 5000 10000 15000 20000 0 5 10 15 20 v is co si ty ( p a .s ) shear rate (1/s) 30c, 3 wt% 40c, 3 wt% 50c, 3 wt% 0 5 10 15 20 25 0 5 10 15 20 25 experimental viscosity (pa.s) p re d ic te d v is c o s it y ( p a .s ) b) testing 0 5 10 15 20 25 0 5 10 15 20 25 experimental viscosity (pa.s) p r e d ic te d v is c o s it y ( p a .s ) a) training al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 1 -qadisiyah journal for engineering sciences . all rights reserved. dr. alaa abdul hasan atiyah , university of technology, department of materials engineering, baghdad. e-mail: dralaadelta@gmial.com dr. saad badry hasson farid , university of technology, department of materials engineering, baghdad. e-mail: dr.saadbhf@gmail.com assist. lec. awham jumah salman , al-furat al-awsat technical university , babylon technical institute, babylon. e-mail: awhamjumah@yahoo.com received on 23 october 2018 accepted on 22 january 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.516 abstract: this work is a study of the effect of polyethylene glycol (peg) on electrophoretic deposition ) epd) of alumina and zirconia particles. the effect of polyethylene glycol as a binder material and the toluene as a dielectric liquid, on the ph of suspension, the final thickness and green density of the deposed parts were studied. there was a difference in the behavior of polyethylene glycol when added for the alumina suspension and the zirconia suspension. the increase in polyethylene glycol was useful to deposit the zirconia more than alumina. the ph for both alumina and zirconia suspension increases with the increase of polyethylene glycol content and with the addition of toluene due to increase of the oh– concentration in the suspension. this increase of ph enhances the particle surface charge and enhances the deposition rate, which led to the increase of density of the deposit. keywords: electrophoretic deposition, polyethylene glycol, toluene, alumina, zirconia, green density. introduction electrophoretic deposition (epd) has attracted a great deal of interest in recent years due to its wide range of coating and part forming applications. it can be applied to any fine powder in a colloidal suspension, including oxides, carbides, nitrides, metals, and polymers. electrophoretic deposition (epd) is proved as a powerful method for the formation of both uniform thin and thick films on substrates of complex geometry [1,2,3].with epd, ceramic bodies are shaped directly in 2012 from a stable colloidal suspension by a dc electric field, which causes the non metallic-surface charged particles to move and deposit on an oppositely charged investigation on the effect of the polyethylene glycol on the electrophortic deposition of alumina and zirconia dr. ali raad hassan and khalid mohsen ali university of technology/ baghdad /mechanical engineering department mailto:dralaadelta@gmial.com mailto:dr.saadbhf@gmail.com mailto:awhamjumah@yahoo.com al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 2 -qadisiyah journal for engineering sciences . all rights reserved. electrode [4,5,6]. suspension preparation is a crucial step in this technique. it is very important to consider the solventdispersant – binder system, in terms of the solubility of binder and additives, the chemical compatibility of the components [7,8]. according to this, the epd process requires the control of the suspension properties as well as the selection and optimization of the electrical parameters involved during forming [9]. several papers have described the preparation of alumina or/and zirconia deposits by epd. these studies focusing on the deposition rate and yield as a function of the process parameters; however, fewer is known about how the process parameters and the suspension composition and properties relate to the behavior of the deposit. it is well known that the packing density of ceramic green parts is of greatest importance in the production of advanced ceramics. for example, the particle packing density in green parts determines the sintering shrinkage, the density of the sintered ceramics, and the number of defects. in order to fully exploit the advantages of the epd process, these elements that affect the structure of the green parts need to be better understood [10,11]. in this work, the effect of the suspension’s composition on the properties of the formed deposit layers is investigated. the goal was to determine the composition for effective and reproducible suspension for fabrication of alumina and zirconia parts, and hence to encourage industrialization of the process. the effect of polyethylene glycol in ethanolic suspensions was analyzed. 1. materials and methods 1.1. materials used the α-al2o3 (hefei ev nano technology,chain; particle size 20-30nm) powder and 3 mol%y2o3– zro2 (hongwu international group ltd; chain; average particle size 70-80 nm) powder were used for the synthesis of alumina or zirconia samples. ethanol (scharlab s.l.,spain) was used as the suspension medium. polyethylene glycol 4000 (sinopharm chemical reagent co.,ltd ,chain) was added to ethanol as a binder material and to enhance particle charging. toluene (avantor performance materials b.v., germany) was also used to study suspension properties. ethanol-based suspensions for the production of dense samples were used. ethylene glycol (peg 4000) was added to the ethanol and must continue to mix by a magnetic stirrer (sh-2 model) to complete dissolve. then the ceramic powder (4g for each 100 ml) was added to the solution and continues to mix in order to formation the suspension. 1.2. description of electrophoretic deposition cell a power supply (h. t. model eisco) was used as a dc supplier in the electrophoretic deposition process. the electrophoretic cell was a 100ml cylindrical glass beaker; and the electrodes were stainless steel (316l) plate with dimensions (2.5 × 2 × 0.1) cm, as show in figure (1) . the distance between the electrodes was 1.2 cm. a variable voltage (60-120v) is used in the course of the process, explicitly, the starting voltage was 60v and increased by 10v every10 minutes, i.e. the total process time is 70 minutes. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 3 -qadisiyah journal for engineering sciences . all rights reserved. figure 1: epd set-up. 1.3. plan work and characteristics the deposited parts two groups of alumina suspensions were prepared in this work in order to study the effect of the polyethylene glycol on green density and thickness of the deposited parts. the first group was a suspension of alumina in ethanol (4g for each 100 ml) and varied weights of peg (0, 0.5, 0.75, 1) g. the second group was composed of a mixture of ethanol and 30% toluene with a varied weight of ethylene glycol ( 0, 0.5 , 0.75 ,1) g for each100 ml of the mixture. also two groups of zirconia suspensions were prepared in order to study the effect of polyethylene glycol on the properties of zirconia parts. the first group was a suspension of zirconia in ethanol (4 g for each 100 ml) and varied weights of peg (0 , 1 , 1.5 ,2) g. the second group was composed of a mixture of ethanol and 30% toluene with varied weight of ethylene glycol (0 , 1 , 1.5 , 2) g for each 100 ml of the mixture. all dimension of the deposits were determined with a micrometer (terma,0-25 mm /0.001mm).the weight of deposits were determined with a digital scale (dm.3,500g×0.01g). the weight of a unit volume of deposited part expressed in grams per cubic centimeter is the green density of the deposited part. it is calculated from dimensions evaluations and the weighting of deposited part as follows [12]: 𝜌𝑔= 𝑚𝑔 𝑉𝑔 [1] where (𝜌𝑔) green density (g/ cm 3) , (𝑚𝑔) green mass of the deposit (g) and (𝑉𝑔) volume of the deposit (cm 3). 2. results and discussions 2.1. study the effect of an applied voltage applying constant voltage (80v) in the electrophoretic process results in an alumina deposit and in an zirconia deposit with the formation of cracks after the drying process as seen in figure (2-a) . this result indicates low green density of the deposited parts. applying higher voltages leads to uneven or irregular deposit. the low voltage is sufficient for low thicknesses but not when the thickness goes higher. st. st. electrodes al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 4 -qadisiyah journal for engineering sciences . all rights reserved. on the other hand, starting with higher voltages results in fast, unsteady deposition process. thus, it is decided to use an incremental increase of the applied the voltage as the thickness of the deposit increase (10v increase every 10 min). this method of applying variable voltages is not preceded by other works as far as we know. the resulting deposit was free of cracks after the drying process; figure (2-b) which indicates a homogeneous deposit with higher density. a b figure 2: effect the type of dc voltage; aconstant voltage (80v), bvariable voltages (60-120 v). 2.2. study the electrophoretic deposition of alumina 2.2.1. the effect of peg addition to the suspension at first, the ph of the solution is monitored. it is found that the addition of peg increases the ph of the suspension when dissolves, as shown in figure (3) . i.e. the peg increases the oh– concentration in the suspension. thus, the peg contributes in increasing the surface charge of the alumina particles in the suspension. accordingly, the addition of the peg is expected to enhance the density and the thickness of the alumina deposit. figure 3: effect of peg on ph of (4g alumina in 100 ml ethanol) suspension. 6.4 6.5 6.6 6.7 6.8 6.9 7 7.1 7.2 0 0.2 0.4 0.6 0.8 1 1.2 p h peg weight (g) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 5 -qadisiyah journal for engineering sciences . all rights reserved. as shown in figure (4-a) , the density of deposit alumina was decreased with the increase the amount of peg and reaches a minimum at 0.75g. for higher amounts of peg, the density is increased due to increase discharge the particles. the thickness of the deposit, figure (4-b) is increased with increasing peg, i.e. it increased with the increasing amount of the suspended alumina. for peg amount higher than 0.75 g, the increased density led to lower thickness. agreen density bthickness figure 4: effect of peg on thickness and green density of deposited alumina. 2.2.2. effect of peg addition to the ethanol-30% toluene suspension the toluene was added to the ethanol in order to decrease the viscosity and dielectric constant of the suspension. the toluene also increases the ph of the suspension because the toluene increases the oh– concentration in the suspension. figure (5) shows the increase of the ph of the suspension with the existence of 30% toluene, which is much higher than without it, as compared with that shown in figure (3). figure 5: effect of peg addition on the ph of ethanol-30% toluene suspensions. the green density of deposited parted were increased with the ethanol-30% toluene suspension of alumina and reached 1.25 g/cm3, as shown in figure (6-a) . this result may be attributed to the higher ph of the suspension due to the including of the toluene and accompanied increase of the surface 0 0.2 0.4 0.6 0.8 1 1.2 0 0.5 1 1.5 g re e n d e n si ty ( g /c m 3 ) peg weight (g) 0 0.5 1 1.5 2 2.5 0 0.5 1 1.5 th ic k n e ss ( m m ) peg weight (g) 9 9.2 9.4 9.6 9.8 10 10.2 10.4 0 0.2 0.4 0.6 0.8 1 1.2 p h peg weight (g) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 6 -qadisiyah journal for engineering sciences . all rights reserved. charges. when the amount of the peg is increased from 0.75 g to 1.0 g, it seems that the viscosity of the suspension is increased beyond the optimum and led to slowing down the particles mobility and accordingly, drops in the deposit density. the thickness of deposit start at high value (3mm) at zero peg content compared with that of ethanol suspension alone (1.92mm), as shown in figure (6-b) . again, the increase of the particle surface charge enhances the deposition rate. the later drop in thickness for higher values of the peg (0.5 and 0.75 g) is due to increase of the density, i.e. due to the increase of packing of the deposit. once more, the unhelpful increase of the viscosity of the suspension at peg content of 1.0 g led to depress the deposition rate and the drop of both the density and the thickness of the deposit. agreen density bthickness figure 6: effect of peg on thickness and green density of alumina deposited from ethanol -30% toluene suspensions. 2.3. study the electrophoretic deposition of zirconia 2.3.1. the effect of peg addition to the suspension at first, the ph of the solution is monitored. it is found that the addition of peg increases the ph of the suspension, as shown in figure (7) . the peg increases the oh– concentration in the suspension. thus, the peg contributes in increasing the surface charge of the zirconia particles in the suspension. accordingly, the addition of the peg is expected to enhance the density and the thickness of the zirconia deposit. figure 7: effect of peg on ph of 4g zirconia in 100 ml ethanol suspension. 0 0.5 1 1.5 0 0.5 1 1.5 g re e n d e n si ty ( g /c m 3 ) peg weight (g) 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 th ic k n e ss ( m m ) peg weight (g) 0 2 4 6 8 10 0 0.5 1 1.5 2 2.5 p h peg weight (g) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 7 -qadisiyah journal for engineering sciences . all rights reserved. as shown in figure (8-a) , the density of deposited zirconia was increase with the increase the amount of peg, this increase is due to the increased particle charge in the suspension. for increase amount of peg, the thickness is decreased. this decrease in thickness occurs due to the increase the packed of deposit with increase the amount of peg. the thickness of the deposit, figure (8-b) is decreased with increasing peg. a-green density b-thickness figure 8: effect of peg on thickness and green density of deposited zirconia from 4g zirconia in 100 ml ethanol suspension. 2.3.2. effect of peg addition to the ethanol-30% toluene suspension figure (9) shows the increase of the ph of the suspension with the existence of 30% toluene, which is much higher than without it, as compared with that shown in figure (7) . this increase in the ph was due to the toluene increased the oh– concentration in the suspension. figure 9: effect of peg addition on the ph of ethanol-30% toluene suspensions. as shown in figure (10-a) ,in ethanol-30% toluene suspension, the density of deposited zirconia was increase with the increase the amount of peg, this increase is due to the increased particle charge in the suspension. the increase in density of the deposited parts from ethanol-30% toluene suspensions comparted with deposited parts from the ethanol suspensions were due to the toluene increases the particle charge in the suspension. 7 7.2 7.4 7.6 7.8 8 8.2 8.4 8.6 0 0.5 1 1.5 2 2.5 p h peg weight (g) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 8 -qadisiyah journal for engineering sciences . all rights reserved. for increase amount of peg, the thickness is decreased. this decrease in thickness occurs due to the increase the packed of deposit with increase the amount of peg. the thickness of the deposit, figure (10-b) is decreased with increasing peg. agreen density bthickness figure 10: effect of peg on thickness and green density of zirconia deposited from ethanol -30% toluene suspensions. conclusion 1the ph of the suspension increase with the increase of peg content and with the addition of toluene due to increase the oh– concentration in the suspension. sometimes, this increase of ph enhances the particle surface charge and enhances the deposition rate, which led to the increase of density of the deposit. 2in ethanol suspension, the increase in content of peg cause of decreasing in the density of alumina deposited parts due to the increase in the viscosity of suspension. in ethanol-30% toluene suspension, the exaggerated content of peg in alumina suspension (beyond 0.75 g) led to increase the ph and decrease the dielectric constant of the suspension with negative effect on the deposition rate. 3with regard to zirconia, the increase in the quantity of polyethylene glycol has had a good effect on the deposition rate because of the high dielectric constant of zirconia powder compared with the alumina powder. 4both the deposit thickness and density increase with the increase of the deposition rate and reach an inflection point where the increase in density led to higher particle packing and thus, reduced deposit thickness. 0 0.5 1 1.5 2 2.5 0 1 2 3 g re e n d e n si ty ( g /c m 3 ) peg weight (g) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 1 2 3 th ic k n e ss ( m m ) peg weight (g) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 9 -qadisiyah journal for engineering sciences . all rights reserved. reference 1. atsushi nakahira ; fumihide nishimura, ” green fabrication of porous ceramics using an aqueous electrophoretic deposition process “,communications of the american ceramic society, vol. 86, no. 7, 2003,pp.( 1230–1232). 2. marijas. lazi; kornelija simovi; vesna b. miskovic-stankovi c ; dusan kicevic, ” the influence of the deposition parameters on the porosity of thin alumina films on steel”, j.serb.chem.soc., vol.69,no.(3) , 2004,pp.(239–249). 3. vesna mišković-stanković, ” electrophoretic deposition of alumina and boehmite coatings on metal surfaces”, macedonian journal of chemistry and chemical engineering, vol. 31, no. 2,2012, pp. (183–193 ). 4. linda berg aas, ” corrosion protection of metals/alloys by epd (electrophoretic deposition)”, master thesis ,norwegian university of science and technology, department of materials science and engineering ,2014. 5. pouya amrollahi; jerzy s. krasinski; ranji vaidyanathan; lobat tayebi;daryoosh vashaee, “electrophoretic deposition (epd): fundamentals and applications from nanoto micro-scale structures”, handbook of nanoelectrochemistry, springer international publishing switzerland,2015. 6. e. caproni ; d. gouvea ; r. muccillo, “yttria-stabilized zirconia closed end tubes prepared by electrophoretic deposition”, science direct ,ceramics international ,vol.37, 2011 ,pp.(273–277). 7. laxmidhar besra ; meilin, “a review on fundamentals and applications of electrophoretic deposition (epd)”, science direct, progress in materials science,vol. 52, 2007 ,pp.(1–61) liu. 8. shaohua zhang ; c.c.sorrel and f.y.li, “electrophoretic deposition of ceramic powder”,j.mater. sci. tehnol., vol.21, 2005 , pp.(107-110). 9. b. ferrari; r. moreno, ”electrophoretic deposition of aqueous alumina slips” ,journal of the european ceramic society, vol. 17,1997,pp.(549-556). 10. sasa novak; katja konig, ”fabrication of alumina parts by electrophoretic deposition from ethanol and aqueous suspensions”, science direct ,ceramics international ,vol.35, 2009,pp.( 2823–2829). 11. eduardo antonelli; ronaldo santos da silva; maria inês basso bernardi ; antonio carlos hernandes, ” electrophoretic deposition of bati 0.85 zr0.15o3 nanopowders”, materials research,vol. 16, no. 6,2013,pp.(1344-134). 12. goupee, a, "methodology for the themomechanical simulation and optimization of functionally graded materials", m. sc. thesis, mechanical engineering,2005, p. (6). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 experimental and numerical investigations of an inflated air-spring made of fiber-reinforced rubber asst. prof. dr. mohsin noori hamzah mechanical engineering department, university of technology email: dr.mohsin@uotechnology.edu.iq mahmood shakir nima (m.sc. student) mechanical engineering department university of technology email: darknewton89@yahoo.com received 13 april 2015 accepted 9 june 2015 abstract air-springs are characterized by strongly anisotropic material behavior and can simultaneously undergo large elastic deformations. this attribute involves an appropriate constitutive model for an adequate numerical simulation of these components' complex response. the present paper discusses the manufacturing process of an air-spring and deals with the use of anisotropic-based hyperelastic constitutive model in the context of thin membranes inflation. in order to investigate the capability of the proposed model, some finite element analysis were conducted by using ansys 15.0. the proposed model shows a good predictive ability and exhibits a good agreement when compared to the experimental work of the present paper. nomenclatures right cauchy deformation tensor f deformation gradient tensor , strain invariants , pseudo strain invarients volume ratio 2 nd piola-kirchhof stress n/m 2 nr natural rubber keywords: air-spring, fiber-reinforced rubber composite, hyperelastic constitutive modeling, anisotropy, finite element analysis. دراسة عملية ونظرية لنابض هوائي مصنوع من مطاط مدعم باأللياف محمود شاكر نعمة email: dr.mohsin@uotechnology.edu.iq أ. م. د. محسن نوري حمزة email: darknewton89@yahoo.com mailto:dr.mohsin@uotechnology.edu.iq mailto:darknewton89@yahoo.com mailto:dr.mohsin@uotechnology.edu.iq mailto:darknewton89@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 الخالصة: تتمتع النوابض الهوائية بخصائص اتجاهية وتمتاز بقابليتها على تحمل تشوهات عالية. هذه الميزات تتطلب إيجاد نموذج صالح لوصف تصرف هذه األجزاء الميكانيكية. هذا البحث يهتم بدراسة طريقة تصنيع النوابض الهوائية، واشتقاق نموذج لوصف (، لغرض التحقق من صحة النوذج (ansys 15.0حليالت عددية باستخدام برنامج تصرف المرونة الشديدة فيها. تم اجراء ت المقترح والذي أظهر توافق جيد وبصورة مرضية عند مقانة النتائج النظرية مع النتائج العملية للبحث. 1. introduction the inflation of hyperelastic rubber-like membranes has been extensively studied in the past. there are two different approaches used to solve this type of problems: the first approach is based on the analytical solutions, while the second one is based on the application of the finite element method (fem) to the problems of membrane inflation. in the context of the first approach, the governing equations of the large strains inflation of axisymmetric membranes were established by (green and adkins, 1960). following the same approach, authors, e.g., (guo, 2001), (kydoniefs and spencer, 1969), (yang and feng, 1970) and (khayat et al., 1992) attempted to solve the problem of the inflation of membranes from an analytical perspective. (guo, 2001) studied the large deformation of a cylindrical hyperelastic membrane circumferentially bonded and sealed at each end to a rigid tube. (kydoniefs and spencer, 1969) obtained an exact general solution of the equations of finite deformations of elastic membranes and applied it to the problem of inflation of a cylinder of finite length sealed at each end by rigid plugs. (yang and feng, 1970) reformulated the mechanics problem concerning large axisymmetric deformations of nonlinear membranes in terms of a system of three first-order ordinary differential equations with explicit derivatives. moreover, (khayat et al., 1992) detailed the occurrence of unstable behaviors in the inflation of neo-hookean membranes with non-uniform radius and thickness. in the context of the finite element method, a simple finite element formulation was presented by (jiang and haddow, 1995) for finite static axisymmetric deformation of isotropic incompressible hyperelastic membranes. that finite element procedure was derived from a finite deformation membrane theory, in which lagrangian type equilibrium equations, expressed in terms of the biot stresses were employed along with constitutive equations relating the principal components of the biot stress tensor and of the principal stretches. based on ogden's non-linear elastic material law, an axisymmetrical membrane element for large deformations was developed by (wriggers and taylor, 1990). more recently, (shi and moita, 1996) studied post-critical response in the inflation of axisymmetric membranes. they performed an extensive parametric study to investigate the nonlinear response of a tube under internal pressure. (verron and marckmann, 2001) presented an axisymmetric b-spline model for the non-linear inflation of both cylindrical and spherical mooneyrivlin membranes. later on, a finite element method was presented by (kyriacou et al., 1996) for geometrically and materially nonlinear orthotropic hyperelastic membranes. the constitutive relations were formulated in terms of the invariants of the 2d right cauchy-green strain tensor and the resulting system of nonlinear equations was solved using a newton-raphson approach. (resse et al., 2001) developed a model to describe the hypereleastic material behavior of pneumatic membrane reinforced with roven-woven fibers. the numerical simulation of a cylindrical membrane was developed for anisotropic hyperelastic materials by (marvalová and nam, 2003). recently, (abdessalem et al., 2011) described a general finite element implementation framework for the constitutive modeling of biological soft tissues. the aim of the present paper is to manufacture an inflated air-spring membrane and propose an anisotropic-based hyperelastic constitutive model that predicts the complex behavior of the membrane. moreover, performing some finite element analyses is another goal of this paper, in al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 order to compare the theoretical response of the membrane with the experimental one and check the validity of the model in solving such a type of problems. 2. experimental work 2.1 the fabrication of the air-spring typically, an air-spring consists of two basic components; a flexible member (the rubbery component) and fixation parts (metal components). the first step of the experimental procedure in this part was to make a mold for manufacturing the flexible member of the air spring according to the desired dimensions. the mold, as shown in figure 1, was manufactured from steel and consisted of two major parts; the drum, and the top cover. the cavity of the mold is situated between the drum and the top cover. the manufacturing steps used for manufacturing the air-spring are briefly summarized in the following steps:  the rubber blend recipe, shown in table 1, was mixed together by using a 2-roll calendering machine according to the rules followed in such processes until reaching complete homogenous blend. the rubber liner produced from calendaring process was coated with a chemical solution prepared by dissolving pieces of the same rubber blend into heptane to enhance the adhesion between the layer of fibers and the rubber liner, as shown in figure 2-a.  a layer of polyester fibers was oriented in 45° with respect to the vertical direction above the rubber liner (figure 2-b), and again the chemical solution was added to the fibers, figure 2-c.  another liner of rubber blend was placed above the layer of fibers forming the first ply of fiber-reinforced rubber composite, figure 2-d.  another ply of fiber-reinforced rubber composite was fabricated in the same manner and placed on the first one in such a way that the layers of fibers were perpendicular to each other, i.e. the layers of fibers were [45/-45] with respect to the vertical.  the mold was coated with a demoulding spray in order to facilitate the demounting of the flexible member of the air-spring out of the mold after curing process.  the two fabricated uncured plies of fiber-reinforced rubber composite were then applied to the building drum of the mold as shown in figure 2-e. the excessive parts of the uncured plies were removed, figure 2-f.  heat and pressure were applied to effect vulcanization of the spring as shown in figure 2-g. the cured flexible member was then removed from the mold and inspected, figure 2-h.  the metal components and the fixation parts for the flexible member were designed and manufactured and then assembled together with the flexible member, figure 2-i, in such a way that the lower end of the air spring is fixed and the upper one is moveable. the air is to be supplied from the lower end via a one-way valve. 2.2 samples preparation and tensile tests the samples preparing processes and tests were done in babylon tire factory laboratories. one of the manufactured flexible members, shown in figure 2-h, was used to harvest the fiber-rubber composite dumbbell specimens. these specimens were cut in each direction of each layer of fibers as shown in figure 3. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 this test was carried out by using monsanto tensometor 10. the effective length of the sample is the distance between the two holders, which was fixed at length (25 mm) according to the astm d412. the composite specimens were tested under a quasi-static speed. the mechanical response of the specimens is shown in figure. 4. 2.3 the test rig in order to check the validity of the proposed model, the air-spring was manufactured in order to be used in a test rig. generally, air-springs are used for actuation and isolation tasks within industrial equipment and within vehicle suspensions. they can replace the metal springs resulting in lighter vehicles and softer riding. the loading for the test rig was meant to mimic the working conditions for an air-spring. firstly, the manufactured air-spring was gradually subjected to internal pressure of 0.1 mpa via the valve on the fixed lower end of the air-spring. this test was carried out by using the tensile test instrument by which an axial displacement was exerted on the moveable upper end of the airspring. the pressurized air-spring was placed between the jaws of the tensile test instrument. the experimental tests were carried out at four different positions of the air-spring. before each stage of loading the inner pressure of the air-spring was measured by using a dial gauge in order to make sure that the pressure was still at the desired value. the mounting plates of the air-spring were at the free height position of the air-spring and then the upper jaw of the tensile test instrument was given a downward movement at a very low speed to fix the upper end of the air-spring at the distance of 5, 10 and 15 mm shorter than the free height. a high-definition digital camera was fixed on a fixed tripod in such a way that the plane of the lens of the camera was facing the air-spring and was perpendicular to the ground as depicted in figure 5. for each case, the inflation profile was captured by the fixed digital camera as shown in figure 6. the captured images were fed to plot digitizer ver. 1.9 to track the deformed side profile of the air-spring. the images were calibrated via three non-collinear points of which the cartesian coordinates are known, then by clicking multiple points on the path of interest, a table of data representing the deformed side profile of the air-spring was created. that table was exported to ms excel and the corresponding deformation of the inflated air-spring was calculated and plotted as shown in figure 7, in order to be compared later with that to be obtained from ansys. 3. constitutive modeling the composite elastomers is considered as an anisotropic hyperelastic and continuous solid, which can be described by the coordinates system x in undeformed state. after deformation the body may be described by the coordinate system x. the deformation gradient, f, defined as , and the volume ratio, j, expressed as | | . the deformation gradient can be decomposed into volumetric and distortional deformation, ( ) ̅. similarly, for the right cauchy-green tensor ( ) ̅ ̅ ̅ ̅ (1) the helmholtz free energy can be decoupled into the volumetric and isochoric parts. furthermore, the isochoric part can be divided into an isotropic (independent of fiber orientations) and an anisotropic part: al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 ( ) ( ̅) ( ̅ ) (2) where and are two fiber directions in the undeformed configuration, figure 8, characterizing the anisotropic behavior of the material, and | | | | . the isochoric part of the strain energy functions can be written in terms of strain invariants, the isotropic part in terms of ̅. additionally, the anisotropic part was written in terms of pseudoinvariants, ̅ and ̅ only, since they are the squares of the stretches in the directions of the fibers, and therefore have a physical interpretation (holzapfel et al., 2000). the strain energy in terms of the modified invariants will be: ( ) ( ̅) ( ̅ ̅) (3) where ̅ ̅, ̅ ̅ , and ̅ ̅ . the volumetric part of the strain energy function is given by: ( ) ( ) (4) the isotropic part of the strain energy function used in this paper is the two term yeoh model (yeoh, 1993): ( ̅)= ( ̅–3)+ ( ̅– ) (5) while the anisotropic part of the strain energy function; i.e. the energy function in the fibers, is assumed in the form of an exponential form (holzapfel, 2000, hamzah, 2013): ( ̅ ̅) [ ( ( ̅ ) )] [ ( ( ̅ ) )] (6) where and are stress-like material parameters and and are dimensionless parameters (holzapfel, 2000). in order to determine the constitutive equations for anisotropic hyperelastic materials in term of strain invariants, the strain energy function, is differentiated with respect to tensor c. by means of the chain rule, the second piola-kirchhoff stress (2nd pk), , can be obtained by decomposing it into volumetric and the deviatoric stress : (7) where and are the volumetric and the deviatoric stress, which they can be expressed as: , (8) ( ̃ ( ̅ ̃) ̅ ) (9) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 and, ̃ ̅ ∑ ̅ ̅ ̅ (10) the derivatives of the modified invariants with respect to the deviatoric part of the right cauchygreen tensor are written as: ̅ ̅ ̅ ̅ ̅ ̅ (11a) the derivatives of the deviatoric part of the strain energy function with respect to the deviatoric part of the strain invariants; ̅ ( ̅ ) ̅ ( ̅ ) ( ( ̅ ) ) ̅ ( ̅ ) ( ( ̅ ) ) (11b) the cauchy (true) stress can be computed from the 2nd pk as, (12) for uniaxial tension, assuming full incompressibility, i.e., j=1, and, , therefore [ ] the derivatives of the modified invariants will be, ̅ ̅ ̅ ̅ [ ( ) ( ) ( ) ( ) ( ) ( ) ] ̅ ̅ [ ( ) ( ) ( ) ( ) ( ) ( ) ] where and are the angles of the first layer and the second layer of fibers, respectively, measured in counterclockwise direction from 1-axis, figure 8. using the above equations with equation (7) obtain: al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 [ ] [ ] [ ̃ ̃ ̃ ̃ ̃ ̃ ̃ ̃ ̃ ] ̃ ( ̃ ̃ ) [ ] (13) since the stresses in the 2 and 3-axes are zero in the case of the uniaxial test, therefore an expression for the hydrostatic pressure can be obtained from equation (13), then substituting the obtained expression of the hydrostatic pressure for the stress in 1-axis, this yields the following constitutive relation, ̃ ̃ (14) where ̃ ( ̅ ) [ ( ̅ ) ( ( ̅ ) )] ( ) [ ( ̅ ) ( ( ̅ ) )] ( ) ̃ ( ̅ ) the material parameters identification was achieved by means of non-linear least-square and a levenberg-marquardt type algorithm to find the best fit for the proposed model, figure 9. all of the obtained material parameters are shown in table 2. 4. finite element analysis the simulation of deformation was implemented in the finite element method, using ansys 15.0. after creating the geometry of the flexible member of the air-spring, the model was meshed with element type solid186 which supports hyperelasticity. the direction of the layers of fibers of [45/-45] with respect to the vertical direction and the material parameters of the proposed model were fed into ansys via ahyper command, this apdl (ansys parametric design language) command is used to solve the problems of anisotropic hyperelasticity materials. the command receives the material parameters table through tb command for volumetric part, the isochoric part and the material directions. the boundary conditions were applied as follows: the lower end of the model was fixed, while the upper one was fixed at its free height position. a pressure of 0.1 mpa was applied to the inner surface of the model. all the previous steps were repeated for axial displacements of 5, 10 and 15 mm. for each state of loading, a path on the line in interest was defined by choosing multiple nodes on the side profile of the deformed shape of the model. this path was mapped onto the amount of deformation in the radial direction. the data resulted from that procedure were fed to ms excel and compared to that obtained in the experimental test rig for each stage of loading as shown in figure. 7. being concerned with the maximum deformation, as one of the criteria for designing the flexible member of the air-spring, the maximum value of predicted deformations are compared to that obtained from the experimental test rig for each stage of loading. table 3 summarizes the accuracy achieved by the proposed model by using the following equation: (15) al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 5. conclusions  the proposed anisotropic hyperelastic constitutive model was based on the decomposition of the strain energy function into isotropic and anisotropic components. the isotropic component was described by a polynomial form of strain energy (yeoh model) with two material parameters. while, an exponential form of the strain energy function with two material parameters for each layer of fibers were used for the anisotropic component.  the discrepancies between test data and simulated data might not vanish completely, which are due to, the fact that the mathematical model cannot completely describe the mechanical behavior of the material, probable imperfections during the manufacturing process and uncertainties in laboratory tests.  the proposed hyperelastic model gave a very good agreement with the experimental results with relatively low number of material parameters to be determined from only a uniaxial extension. references [1] abdessalem j., kallel i.k., fakhreddine d., “theory and finite element implementation of orthotropic and transversely isotropic incompressible hyperelastic membrane”, multidiscipline modeling in materials and structures vol. 7, no. 4, pp. 424-439, 2011. [2] green a.e., adkins j.e., large elastic deformations and non-linear continuum mechanics, clarendon press, oxford, 1960. [3] guo x., “large deformation analysis for a cylindrical hyperelastic membrane of rubber-like material under internal pressure”, rubber chemistry and technology, vol. 74, no. 1, pp. 100-115, 2001. [4] hamzah m.n., subit d, boruah s., forman j., crandall j., ito d., ejima s., kamiji k., yasuki t., “an inverse finite element approach for estimating the fiber orientations in intercostal muscles”, ircobi conference 2013, gothenburg, pp. 722-733, 2013. [5] holzapfel g.a., gasser t.c., ogden r.w., “a new constitutive framework for arterial wall mechanics and a comparative study of material models”, journal of elasticity, vol. 61, pp. 1-48, 2000. [6] jiang l., haddow j.b., “a finite element formulation for finite static axisymmetric deformation of hyperelastic membranes”, computers and structures, vol. 57, no. 3, pp. 401-405, 1995. [7] khayat r. e., derdouri a., garcia-rejon a., “inflation of an elastic cylindrical membrane: nonlinear deformation and instability”, international journal of solids and structures, vol. 29, no. 1, pp. 69-87, 1992. [8] kydoniefs a.d., spencer a.j.m., “finite axisymmetric deformations of an initially cylindrical elastic membrane”, quarterly journal of mechanics and applied mathematics, vol. 22, no. 1, pp. 87-95, 1969. [9] kyriacou s. k., humphrey j. d., schwab c., “finite element analysis of nonlinear orthotropic hyperelastic membranes”, computational mechanics, vol. 18, no. 4, pp. 269-278, 1996. http://www.sciencedirect.com/science/article/pii/004579499400629h http://www.researchgate.net/researcher/2040822984_a_j_m_spencer http://link.springer.com/search?facet-author=%22s.+k.+kyriacou%22 http://link.springer.com/search?facet-author=%22c.+schwab%22 http://link.springer.com/journal/466/18/4/page/1 al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 535 [10] marvalová b., nam t.h., “deformation analysis of an inflated cylindrical membrane of composite with rubber matrix reinforced by textile material cords”, proceedings of the international conference on engineering mechanics, svratka, czech republic, pp. 194-195, 2003. [11] reese s., raible t., wriggers p., “finite element modeling of orthotropic material behavior in pneumatic membranes”, international journal of solids and structures, vol. 38, pp. 9525-9544, 2001. [12] shi j., moita g.f., “the post-critical analysis of axisymmetric hyperelastic membranes by finite element method”, computer methods in applied mechanics and engineering, vol. 135, pp. 265-281, 1996. [13] verron e., marckmann g., “an axisymmetric b-spline model for the non-linear inflation of rubber-like membranes”, computer methods in applied mechanics and engineering, vol. 190, pp. 62716289, 2001. [14] wriggers p., taylor r.l., “a fully non-linear axisymmetrical membrane element for rubberlike materials”, engineering computations, vol. 7, no. 4, pp. 303-310, 1990. [15] yang w.h., feng w.w., “on axisymmetrical deformations of nonlinear membranes”, journal of applied mechanics, vol. 37, no. 4, pp. 1002-1011, 1970. [16] yeoh o.h., “some forms of the strain energy function for rubber”, rubber chemistry and technology, vol. 66, issue 5, pp. 54-771, 1993. table (1): the rubber blend recipe. phr material 011 nr 1.0 renacit 5 zinc oxide 1.9 stearic acid 46.5 carbon n326 6.89 process oil 0.55 phenol tack resin 1.59 recorcinol 1.1 tmq 0.53 mbs 0.21 ctp-100 0.84 hmt 3.39 insoluble sulphur al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 table (2): material parameters obtained from curve fitting process. (mpa) (mpa) (mpa) (mpa) 1.653 -0.3287 63.33 -0.06319 63.33 -0.06319 table (3): comparison of maximum deformation between the experimental test rig and fea analysis. at free height displacements 5 mm 10 mm 15 mm experimental deformation 3.131 4.688 7.035 9.279 predicted deformation 3.444 5.104 7.448 9.695 error % 9.088 8.15 5.545 4.291 (a) (b) figure (1): the manufactured mold, (a) the drum, (b) the top cover. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 figure (2): manufacturing steps of the air spring. figure (3): the fiber-rubber specimens cut in each fibers' direction. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 figure (4): the mechanical behavior of the fiber-reinforced rubber composites tested at a quasi-static speed. figure (5): schematic for the experimental rig. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 figure (6): loading stages of the inflated air-spring pressurized with 0.1 mpa, (a) at free height, (b) displaced 5 mm, (c) displaced 10 mm, (d) displaced 15 mm. a b al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 533 c d figure (7): a comparison between the experimental and the predicted deformations of the flexible member of the air-spring pressurized with 0.1 mpa, (a) at free height, (b) displaced 5 mm, (c) displaced 10 mm, (d) displaced 15 mm. figure (8): the fibers' orientation inside the rubber. figure (9): curve fitting procedure. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 -six foralgorithm optimization of gear teeth numbers genetic automatic transmissionlepelletier velocity essam lauibi esmail nabel kadum abd-ali asia abdulsattar al-ebadi assistant professor, department dr. department of mechanical asst. lecturer department of of mechanical engineering, engineering al-qadissiyh mechanical engineering al al-qadissiyh university, iraq university, iraq qadissiyh university, iraq dr.essamesmail@yahoo.co nabelkadum@yahoo.com asiarazak@yahoo.com received 2 august 2015 accepted 30 august 2015 abstract this paper concentrates on the application of genetic algorithm optimization technique to find the gear teeth numbers for six-velocity lepelletier automatic transmission with given approximate velocity ratios and a set of design constraints. matlab is employed to find the gear teeth numbers and the velocity ratios satisfying the design and geometric constraints. keywords: automatic transmission, epicyclic gear mechanism, genetic algorithm, lepelleter, nomographs, optimization, ravigneaux, velocity ratios اليجاد عدد االسنان االمثل لناقل حركة نوع ذو ست سرع استخدام الخوارزمية الجينية الخالصة تركز الدراسة الحالية على تطبيق تقنية االمثلة باستخدام الخوارزمية الجينية للحصول على اعداد االسنان المثلى لتروس ناقل حركة من لنسب السرعة ومجموعة محددات التصميم . تم استخدام برنامج نوع ليبيلتديا ذو السرع الستة وذلك بمعطيات تقريبية اليجاد عدد اسنان ناقل الحركة ونسب السرعة التي تلبي التصميم والقيود الهندسبة . ماتالب introduction to achieve a set of desired velocity ratios, most automatic transmission mechanisms employ epicyclic gear trains (egts). the velocity ratio can define as the ratio of the velocity of the input link to the output link of a transmission mechanism. an epicyclic gear mechanism (egm) employing a ten-link lepelleter gear train as an automatic transmission is shown in figure (1). depending on the clutching condition, seven drives called first under-drive, second under-drive, third under-drive, fourth under-drive, first over-drive, second over-drive and reverse-drive are feasible. these seven clutching conditions are shown in table 1, where an x indicates that the corresponding clutch ci or brake bi is activated on the i th link of the gear train. lepelleter lepelleti er matlab mailto:dr.essamesmail@yahoo.co mailto:nabelkadum@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 lepelletier egt can be analyzed as a compound of two fges. one fge is a single-planet simple gear train and the second fge is a double-planet ravigneaux gear train. figures 2 shows a schematic drawing of these gear trains. simionescu et al. [2] proposed an optimization method to synthesis the gear-teeth number for a two under drive ravigneaux type automatic transmission with a direct drive and a reverse. all possible assembly and interference avoidance requirements were considered as constraints to form an optimization problem. it was then solved with the aid of an estimation of distribution algorithm. esmail [3-5] proposed an optimization technique to synthesis gear-teeth numbers of epicyclic gear trains. conventionally available automatic transmissions are used to demonstrate the methodology. the proposed technique enables the designer to synthesize the number of teeth of all gears and satisfying all the design constraints in a single run. hwang and huang [6] proposed a methodology for the design of six-speed automatic transmissions. six configurations of six-speed automatic transmissions were synthesized from the eight-link two-dof ravigneaux gear mechanism. unfortunately, they did not include the included angle of planet gears into their consideration, resulting in an impractical and infeasible design. hsu [7] presented an analytic method for the synthesis of the number of teeth of gears for an epicyclic gear mechanism with the clutching sequence table and the speed ratios. this approach is far more successful with simple gear trains having no design constraints. hsu and huang [8] synthesized the number of teeth of all gears of six speed ravigneaux-type automatic transmissions by assigning three (out of seven) desired speed ratios in the analytic method proposed by hsu [7]. hsu‘s method becomes a trial and error method when applied to the six-speed ravigneaux-type automatic transmission; a method of reaching satisfactory results by trying out certain desired speed ratios until other speed ratios and the design constraints are satisfied. it is lengthy and tedious. hsu and huang [8] concluded that the ravigneaux gear mechanism could reach six forward speeds at most. an artificial neural network and a genetic algorithm are used by shamekhi et al. [9] for the optimization of the gear ratios and gear teeth numbers of simpson gear train with an error less than ±0.3%. design constraints for the design to be feasible, the following requirements must be met: 1. considering the driving performance of an automatic transmission, the absolute value of the velocity ratio of the reverse velocity rrd should be at least between the first and the second under drive velocity ratios. | | (1) 2. the velocity ratio steps for forward velocities should be greater than 1.275. (2) 3. the difference in adjacent velocity ratio steps should be less than (±0.25). | | (3) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 4. the highest overdrive velocity ratio must equal to or greater than 0.5. (4) 5. in order to facilitate load sharing and to make sure that there are four sets of combinations of planet gears arranged 90° apart from one another, the included angle of planet gears should be at least less than 84°. a space (s) of 6º is left to avoid contact between neighboring planet gear sets. obviously, since the number of sets of combinations of planet gears (pgs) depend on the included angle, it can be written as (5) and 6. a practical gear train can’t have too large or too small gear sizes. to avoid undercut, the minimum number of teeth on the planet gears is limited to 15. considering the geometry relations of the lepelletier gear mechanism, gear teeth number of ring gear-teeth should be 85 or less. (6) optimization of gear ratios for egts the optimization of gear teeth numbers of automotive automatic transmissions is a multi-objective task. due to conflicts among objectives, it is impossible to obtain a single design that corresponds to optima of all the objectives. the optimization of gear teeth numbers can be solved using singleobjective ga optimization method if all but one objective are converted into constraints. a genetic algorithm (ga) is a search and optimization method which works by mimicking the evolutionary principles and chromosomal processing in natural genetics. to achieve a specific set of velocity ratios the designer has to choose a gear train, a set of clutches that are to be operated in a chosen sequence, and a set of gears that have a specific number of teeth. in practice, one wants to choose a set of gears to achieve a set of velocity ratios, i.e., the design variables are the gear teeth numbers. in the particular case of lepelletier gear train, the design variables are eight (z1, z2, z3, z4, z5, z6, z7, and z8) and can only take integer values. in what follows, a genetic algorithm matlab optimization method is proposed to complete this design problem. by assigning numerical values to the approximate velocity ratios, using the mechanism kinematic and geometric constraints and based on a set of design variables, matlab optimization can generate the possible gear ratios and their associated gear-teeth numbers in a single run (see appendix). formulation of the optimization traditionally, the velocity ratio is used to study the velocity between links x and y with reference to link z where x, y and z are any three links in the egt [10]. a methodology for expressing the overall velocity ratio of an egm in terms of its fges was recently developed by esmail [10]. in his approach, the concept of virtual planet gear ratio is applied for the kinematic analysis of egms. the egm is decomposed into several egtes; one of them is considered as the primary egte. then the virtual al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 191 planet gear ratios associated with various egtes are investigated. they are found in terms of the planet gear of the basic egte. this way, the velocity ratio of an egm can be symbolically expressed in terms of the teeth number of each gear. the velocity ratio is written in terms of the planet gear ratios as (7) the term "planet gear ratio" refers to the ratio of the number of teeth on two meshing gears. it is defined by the ratio of a planet gear p with respect to a sun or ring gear x, where zp and zx denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative sign depends on whether x is a ring or sun gear. ⁄ (7a) the virtual planet gear ratio is defined as the planet gear ratio measured, with respect to the primary epicyclic gear train entity (egte), in an epicyclic gear mechanism. ( ) (7b) where np,b1 and np,b2 are associated with the basic egte and is associated with the secondary egte. therefore, a link may have more than one virtual planet gear ratio depending on the connecting links that connect the primary egte to the egte to which the virtual link belongs. the virtual planet gear ratio is written in bold to differentiate it from the actual planet gear ratio which is written in italic. the velocity ratio between links x and y with respect to a third link z may have more than one value depending on the connecting links that connect the primary egte to the egte to which a virtual link belongs. optimization technique and problem a fitness function ( ) is defined in terms of the velocity ratios, rk, for the gear train. the fitness function is the sum of squared residuals, a residual being the difference between the desired velocity ratio and the actual velocity ratio. the fitness function also ensures that a best set of gear teeth numbers is achieved that would give the desired velocity ratios without violating any of the design and geometric constraints. for minimizing the error between desired and optimized velocity ratios, the fitness function is written as ( ) ∑ ( ) (8) where f(z) is the fitness function, z is the vector of design variables (z1, z2,…….,zm), n is the number of velocity ratios, is the k th optimized velocity ratio, s the k th desired velocity ratio. the velocity ratios r1,r2 . . . rn depend on the topology of the gear train and the clutching sequence. the constraints under which the function is minimized will depend on the gear train being considered. the fitness function is subjected to the following constraints al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 ( ) (9) ( ) (10) [ ] (11) where and present inequality and equality constraints, are the upper and lower bounds on the m th design variable respectively. formulation for lepelletier gear train lepelletier egt can be analyzed as a compound of two fges. one fge is a single-planet simple gear train and the second fge is a double-planet ravigneaux gear train. the clutching sequence, which includes the brake clutches, is assumed to be the same as those mentioned in table 1. to relate the velocity ratios to the gear teeth numbers, the system of eqs. (7) was solved seven times, each time for a different clutching condition. some velocity ratios also have the same labeling, are different in value, depending on the common links between the egtes. under certain clutching condition the ravigneaux part of the gear train may act as a rigid body, in such a case the overall velocity ratio will be equal to the velocity ratio of the simple part of the transmission. the under-drives can be written as follows: ( ) (12) ( )( ) ( ) (13) ( ) (14) ( ) (15) the over-drives are written as follows: ( ) (16) ( ) (17) the reverse-drive is written as ( ) (18) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 it should be realized that for an arbitrary combination of desired velocity ratios there may not be a set of solutions for the gear teeth numbers zm that satisfy eqs. (12) to (18). in other words, the ideal minimum value of the fitness function( ( ) ) may or may not be achievable. the constraints under which the function ( ) is minimized for the lepelletier gear train are now described. design constraints for lepelletier gear train as previously stated, and are the reverseand first under drive velocity ratios, respectively. examining the first design constraint, it is convenient to rewrite it in the form | | (19) substituting equation (12) and (18) into equation (19) and dividing through by ( ) yields (20) this implies that for | | to be greater than | | as required by the first design constraint, z2 must be smaller than z1 or (21) for the lepelletier gear train, the velocity ratio steps for forward velocities should be greater than 1.275. thus, the second design constraint can be written as (22) (23) (24) (25) (26) the third design constraint is | | (27) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 as required by the fourth design constraint, the highest overdrive ratio is equal to or greater than 0.5. rewriting the third design constraint in terms of the variables used in the governing equations, ( ) (28) prove since the ring gear is always larger than the sun gear, then equation (28) implies that the second over drive velocity ratio rod2 is always greater than the 0.5 value required by the third design constraint. geometric constraints we can get the geometric constraints for the lepelletier gear train from figs. 1 and 2. the sum of the number of teeth of the sun gear and twice the number of teeth on the planet gear should equal the number of teeth on the ring gear. let dm be the diameter of a gear element m, then d4 +2d6 = d1. if the diameteral pitch p of all the gears is the same, then dm = p. zm and z4 + 2z6 = z1 also d3 + 2d7 = d8 or z3 + 2z7= z8. by taking account of the presence of the planet gears between the sun and ring gears, it is obvious that dsun should be smaller than dring, which can be represented equivalently as z1-z4 ≤ 0. similarly, z8-z3 ≤ 0. for planet gear 5 to be out of line with planet gear 6, the diameter of planet gear 5 should be at least as large as the difference between the radii of the large and small sun gears, which can be equivalently represented as (29) in order to facilitate load sharing and to make sure that there are four sets of combinations of planet gears arranged 90º apart from one another, the included angle of planet gears should be smaller than 90º. the included angle of planet gears 5 and 6, shown in fig. 3, is used as a design constraint in the optimization problem for its value to lie within the limit. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 194 by applying the cosine law for triangle bac and using the sine for triangles bae and cad, we get: [ ( ) ( ) ( ) ( )( ) ] ( ) the first term in equation (30) must satisfy the following condition to give reliable values [ ( ) ( ) ( ) ( )( ) ] ( ) obviously, since the number of sets of combinations of planet gears (pgs) depend on the included angle, it would be advantageous to select an angle that would place all the sets in the range between . (32) (33) optimization results the designer specifies the gear train, the clutching sequence and the design constraints on the velocity ratios to be achieved. the optimization problem starts at an arbitrary velocity ratios and at the end of its execution displays the optimized gear teeth numbers. analytical or trial and error approaches for finding the gear teeth numbers of an automotive automatic transmission to satisfy the design constraints has been eliminated by formulating the problem as a ga optimization problem. the implementation of genetic algorithm was performed in matlab. the stopping condition is the number of generations. starting with a population size of 200, number of generations as 1000, probability of crossover as 0.8 and probability of mutation as 0.2, the code was executed. the optimization procedure was successfully applied to find those teeth numbers of the gear train for which the constraint are satisfying the original specification. the optimized gear teeth numbers shown in table 2 satisfy the geometric and kinematic constraints given by eqs. (19) to (33). carrying out a search to obtain the sets of optimized gear teeth numbers, yields the values shown in table 2. in fact, ga provided different results from run to run with the same objective value of 1.89528×10 -7 . the fundamental constraints regarding the included angle, reverse velocity ratio, velocity ratio steps, and the difference in velocity ratio steps are all satisfied. for example, the values for the velocity ratio steps are 4.4410, 4.4444, 4.4449, 4.4441, and 4.4444 and for the difference in velocity ratio steps are 1.4444, 1.4111, 1.1144, and 1.1414. the solutions found by the genetic algorithm are as good as the best solution in the literature. figure 4 shows a matlab plot to the optimization results for the gear teeth numbers given in the fifth row of table 2. by applying explicit enumeration of all possible (85-15) 8 =576480.1×10 9 gear teeth combinations, the ga solutions are found to be globally optimal. a single globally optimal solution is not always al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 199 sufficient when multiple global optima exist. one reason is that the design at this stage is far from complete and further steps in the design’s analysis are needed to determine the teeth numbers based on the transmitted power. the existence of multiple global optima gives the designer the ability to quickly select a gear teeth combination, depending on how the gear train is intended to react to both the power requirements of the gear train and the velocity response of the planetary train. the gear teeth combination shown in the ninth row of table 2 is identical to that reported in lepelletier patent [1]. however, it seems that the included angle of planet gears is not considered in that work. since the associated included angle is 90.0634º, then three sets of combinations of planet gears arranged 120° apart from one another are used. it can be seen that the effect of gear teeth numbers on the included angle is always through planet gear 5. obviously, the designer could select a high included angle, but this would fail the fifth design constraint, requiring that the included angle is only slightly smaller than 84º. selecting any one of the gear teeth combination shown in the first to the fifth rows of table 2, ensures that there will be four planet gear sets arranged 90º apart from one another. the approach used to find the gear teeth numbers must be weighed against the changes that may have to be made in the velocity ratios during the optimization process. approximate velocity ratios that are assumed in the beginning of the optimization process, may have to be modified with respect to the optimized values of the gear teeth numbers. the modification depends on how the gear train is intended to react to the fundamental constraints regarding the included angle, reverse velocity ratio, velocity ratio steps, and the difference in velocity ratio steps. hence, an iterative procedure between the values achieved by the optimization process and those required to satisfy the design constraints may have to be done. references [1] p. a. g. lepelletier, “multispeed automatic transmission for automobile vehicles,” us patent no. 106352, 1992. [2] simionescu pa, beale d, dozier gv (2006) teeth-number synthesis of a multispeed planetary transmission using an estimation of distribution algorithm. asme j mech des 128(1):108–115. doi:10.1115/1.2114867 [3] esmail el, salih kh (2011) synthesis and optimization of epicyclic-type automatic transmissions based on nomographs. al-qadisiya journal engineering science, 4(3):168–185. [4] esmail, e. l. , 2013, "nomographs and feasibility graphs for enumeration of ravigneaux-type automatic transmissions ", advances in mechanical engineering hindawi, publishing corporation, volume 2013 (2013), article id 120324, 15 pages http://dx.doi.org/10.1155/2013/120324. [5] esmail, e. l. , 2013, "nomographs for synthesis of epicyclic-type automatic transmissions", meccanica, october 2013, volume 48, issue 8, pp 2037-2049. doi 10.1007/s11012-013-9721-z. [6] hwang wm, huang yl (2005) configuration design of six-speed automatic transmissions with two-degree-of freedom planetary gear trains. trans can soc mech eng 29(1):41–55. http://dx.doi.org/10.1155/2013/120324 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 411 [7] hsu ch (2002) an analytic methodology for the kinematic synthesis of epicyclic gear mechanisms. asme jmech des 124:574–576. [8] hsu ch, huang rh (2009) systematic design of six speed automatic transmissions with an eightlink two-dof ravigneaux gear mechanism. asme j mech des. 131:011004-1–011004-8 [9] amir h. shamekhi, abbas bidgoly, ebrahim n. noureiny, 2014, optimization of the gear ratios in automatic transmission systems using an artificial neural network and a genetic algorithm, proceedings of the institution of mechanical engineers, part d: journal of automobile engineering 0954407014528887. [10]esmail, e.l., 2007, "kinematic nomographs of epicyclic-type transmission mechanisms", emirates journal for engineering research, volume 12, issue 3, pp. 47-55. table (1): clutching sequence for six-velocity lepelletier automatic transmission [1]. c1 c2 c3 b1 b3 velocity ratio ud1 x x 4.135 ud2 x x 2.363 ud3 x x 1.508 ud4 x x 1.140 od1 x x 0.860 od2 x x 0.675 rd x x -3.127 table (2): gear teeth-numbers of the six-velocity lepelletier gear train for different values of included angle with the same objective value of 1.89528×10 -7 .. achieved gear-teeth numbers included angle (in degrees) z1 z2 z3 z4 z5 z6 z7 z8 41 31 61 85 15 22 15 31 75.0147 41 31 61 85 16 22 15 31 77.2695 41 31 61 85 17 22 15 31 79.3944 41 31 61 85 18 22 15 31 81.4034 41 31 61 85 19 22 15 31 83.3083 41 31 61 85 20 22 15 31 85.1188 41 31 61 85 21 22 15 31 86.8435 41 31 61 85 22 22 15 31 88.4896 41 31 61 85 23 22 15 31 90.0634 41 31 61 85 24 22 15 31 91.5704 41 31 61 85 25 22 15 31 93.0157 41 31 61 85 26 22 15 31 94.4036 . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 31 61 85 33 22 15 31 102.7958º 41 31 61 85 35 22 15 31 104.8470 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 414 . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 31 61 85 51 22 15 31 117.6214 41 31 61 85 53 22 15 31 118.8818 41 31 61 85 54 22 15 31 119.4906 41 31 61 85 55 22 15 31 120.0860 figure (1): six-velocity lepelletier automatic transmission [1]. (a) (b) figure (2): the functional schematics of (a) simple gear train, and (b) ravigneaux gear train. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 414 figure (3): the included angle of planet gears 5 and 6 shown in fig. 1 figure (4): a matlab plot to the optimization results for the gear teeth numbers given in the fifth row of table 2. appendix : (1) matlab objective function m.file (lepelletier.m) function f=lepelletier(z) r1=z(3)*(1+(z(7)/z(8)))/z(2); r2=((z(7)/z(8))+1)*((1/z(1))+1/z(2))/((1/z(3))+1/z(1)); r3=1+(z(7)/z(8)); r4=(1/z(2))*(1+z(8)/z(7))/((1/z(2))*(1+z(8)/z(7))-1/z(3)); r5=(1/z(1))*(1+z(8)/z(7))/((1/z(1))*(1+z(8)/z(7))+1/z(3)); r6=z(3)/(z(1)+z(3)); r7=-(z(3)/z(1))*(1+z(7)/z(8)); k1=4.135;k2=2.363;k3=1.508;k4=1.1401;k5=0.86019;k6=0.6746;k7=-3.1267; f=((k1-r1)^2+(k2-r2)^2+(k3-r3)^2+(k4-r4)^2+(k5-r5)^2+(k6-r6)^2+(k7-r7)^2); (2) matlab nonlinear constraints m.file (lepelletier_confune_ga.m) function [c, ceq] =lepelletier_confune_ga(z) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 414 thetaupper=84; thetalower=82; theta=acosd(((z(2)+z(4))^2+(z(5)+z(1))^2(z(5)+z(4))^2)/(2*(z(5)+z(1))*(z(2)+z(4))))+asind(z(5)/(z(1)+z(5)))+asind((z(4)/(z(4)+z(2)) )); r1=z(3)*(1+(z(7)/z(8)))/z(2); r2=((z(7)/z(8))+1)*((1/z(1))+1/z(2))/((1/z(3))+1/z(1)); r3=1+(z(7)/z(8)); r4=(1/z(2))*(1+z(8)/z(7))/((1/z(2))*(1+z(8)/z(7))-1/z(3)); r5=(1/z(1))*(1+z(8)/z(7))/((1/z(1))*(1+z(8)/z(7))+1/z(3)); r6=z(3)/(z(1)+z(3)); r7=-(z(3)/z(1))*(1+z(7)/z(8)); k1=4.135;k2=2.363;k3=1.508;k4=1.1401;k5=0.86019;k6=0.6746;k7=-3.1267; e1=(r1/r2);e2=(r2/r3);e3=(r3/r4);e4=(r4/r5);e5=(r5/r6); s1=abs(e1-e2);s2=abs(e2-e3);s3=abs(e3-e4);s4=abs(e4-e5); optimal_included_angle_c=[theta] velocity_ratio_steps=[e1 e2 e3 e4 e5] difference_in_velocity_ratio_steps=[s1 s2 s3 s4] velocity_ratios=[r1 r2 r3 r4 r5 r6 r7] velocity_ratios_d=[k1 k2 k3 k4 k5 k6 k7] c = [2*z(6)+z(7)-z(8);-2*z(6)-z(7)+z(8);2*z(5)+z(1)-z(3);-2*z(5)-z(1)+z(3); z(1)-z(2)-2*z(4);z(7)-z(8);z(2)-z(3);z(1)-z(3);z(2)-z(1);r2-abs(r7); 1.275-(r1/r2);1.275-(r2/r3);1.275-(r3/r4);1.275-(r4/r5);1.275-(r5/r6); abs(e1-e2)-0.25;abs(e2-e3)-0.25;abs(e3-e4)-0.25;abs(e4-e5)-0.25; theta-thetaupper; -theta+thetalower; abs(((z(2)+z(4))/z(5))^2+(1+(z(1)/z(5)))^2-(1+(z(4)/z(5)))^2)abs(2*((1+(z(1)/z(5))*((z(2)+z(4))/z(5)))))]; ceq =[]; (3) matlab optimization m.file (lepelletier_ga.m) function [x,fval,exitflag,output,population,score] = lepelletier_ga(nvars,lb,ub,intcon,generations_data,stallgenlimit_data) nvars=8; lb=[15 15 85 15 15 15 15 15]; ub=[85 85 85 85 85 15 85 85]; intcon=[1 2 3 4 5 6 7 8]; generations_data=100; stallgenlimit_data=100; options = gaoptimset; options = gaoptimset(options,'generations', generations_data); options = gaoptimset(options,'stallgenlimit', stallgenlimit_data); options = gaoptimset(options,'display', 'final'); options = gaoptimset(options,'plotfcns', { @gaplotbestf @gaplotbestindiv @gaplotstopping }); [x,fval,exitflag,output,population,score] = ... ga(@lepelletier,nvars,[],[],[],[],lb,ub,@lepelletier_confune_ga,intcon,options); template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 256 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. effect of the wire mesh reinforcement on some properties of the precast concrete tiles lecturer/dr. zainab m. r. abdul rasool, university of kerbala , college of engineering, department of civil engineering. email:zainabn8@yahoo.co.uk lecturer/ laith mohammed ridha mahmmod, university of kerbala , college of engineering, department of civil engineering. email:laithmrmahmood@gmail.com asst.lecturer/ mushtaq sadiq radhi, university of kerbala , college of engineering, department of civil engineering. email:mushtaq.sadiq@uokerbala.edu.iq abstract: the possibility of improving some properties of precast concrete tiles under static load has been studied in this research. the experimental approach was adopted in this research to investigate the effect of two types of wire mesh reinforcements on some properties of precast concrete tiles especially flexural failure load. the experimental program is divided into three groups with two ages of the test, the result of each age is an average of three specimens; the first group consists of six specimens which refer to reference tiles, the second group consists of eighteen specimens reinforced with different shapes of a metal wire mesh. the third group consists of eighteen specimens reinforced with different shapes of the plastic wire mesh. three tests were conducted in this research, flexural failure load, density, and absorption. the main conclusion from this research is; the increasing in flexural failure load of specimens tiles according to reference tiles was 10%, 17% and 25% for tiles reinforced with square plastic wire mesh, stripe plastic wire mesh and specific plastic wire mesh, and 33%, 35% and 21% for square metal wire mesh, stripe metal wire mesh, and specific metal wire mesh respectively. keywords: tiles, metal, wire mesh, plastic, flexural failure load, reinforcements. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 257 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 1. introduction pre-cast concrete tiles are the construction material which is used in roofing or flooring and consists of cement, sand, and gravel with a maximum size of (12) mm. some material may be added such as the pigment in the colored surface of the upper tiles or other additives in such cases to improve the properties of the concrete used in its manufacture (iraqi specification no.1107, 1987) (shah and key, 1972; netlon, 1988; engel and bakis, 2001), through their researches, have reached that, there is a possibility to improve the properties of precast concrete tiles, especially resistance to flexural and impact through the using of reinforcements with different materials, such as fibers, since these materials will contribute to the followings: 1improving durability and sustainability. 2improving mechanical properties. 3increasing susceptibility of tiles to absorb shocks. 4decreasing damage ratio during transfers or sudden bumps. 5-decreasing amount cracks poetic expected to occur during the molding and processing. (al-mashhadani et al, 2007) , studied the reasons for the repetitive failure during concrete tiles testing. in their experimental program, in addition to full-scale concrete tiles, cubes, prisms, and cylinders were prepared, the tiles were divided into two groups; the first one was cast with the same concrete mixture used in a local factory of tiles in iraq, while the other group contained tiles with a new different mix design, to study the effect of mix proportion on the properties of tiles. the test results showed that the properties of the second group are better than that of the first one. this failure may be due to badly proportioned concrete or due to bad quality control such as curing conditions. a newly suggested model was cast and tested, by using the metal wire mesh addition to the same concrete proportion of group two, the test results showed the newly suggested tiles were more resistant to breaking by (+21%) in comparison with the tiles without metal wire mesh. another study was conducted by (thweny, 2013) to improve the properties of concrete roof tiles by using propylene-ethylene copolymer waste materials as a grid to reinforce the roof tiles, it was found that the flexural failure load for reinforced tiles increased by (81%) when compared to that without reinforcement. likewise, the impact resistance of the tiles was increased, which the required number of blows that cause failure 26 and 3 blows for the reinforcement tiles and without reinforcement tiles, respectively. (sahu and jain, 2015) explored the compressive strength, splitting tensile strength and flexural strength properties of concrete reinforced with short discrete fibers. the study was carried out on concrete with (20) mpa compressive strength, the size of glass fibers used was (30) mm and the fiber content was varied from (0%) to (0.3%) of the total weight of concrete. in studying the above three properties no admixture was used. some conclusions from this research, the strength of tiles increases and this increasing has been found with the addition of fibers, and the water absorption of the concrete also decreases with increase in fiber content. studying the output of (darsana et al. 2016) reveals that natural fibers such as coir can be used for the improvement of concrete roof tiles. through testing, it was identified that concrete roof tiles with coir fibers demonstrate better ductility relating to those of concrete flag without fibers. moreover, the flexural failure load was increased by 25%. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 258 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 2. objective of research in spite of the frequent failure of precast concrete tiles in iraq, especially with flexural failure load test and do not confirm the limits of iraqi specification, this research aims to improve the properties of iraqi precast concrete tiles and increase its flexural failure load. thus, the objective of this study is to investigate the effect of wire mesh reinforcement on some properties of precast concrete tiles by utilizing two types of locally available wire mesh, plastic and metal, in different plan shape, grid orientation of each type on the main property (flexural failure load) that specify the concrete tiles that used in the roofing and flooring. additionally the density and water absorption of specimens was also inspected. 3. the experimental work the experimental part of this study involves casting (42) specimens of concrete tiles separated into three groups; each group was tested in two ages. group one consists of six specimens; all specimens of this group were plain concrete without any reinforcement, these specimens considered as the control specimens as the same tiles available in local markets and already used in construction projects for roofing purposes. the second group consists of (18) specimen's reinforced with the metal wire mesh in three patterns, the first is a square shape, the second is a specific shape, and the third is reinforced by longitudinal strips. the third group consists of (18) specimen's reinforced by the plastic wire mesh in three patterns similar to the reinforcement of metal wire mesh. 3.1 materials 3.1.1 cement sulfate resisting portland cement manufactured in iraq with the trademark of (al-jeser) was used throughout this investigation, its properties are listed in table (1) and confirm the limits of (iraqi specification no.5, 1984). table 1. physical and chemical properties of cement chemical composition, % oxide composition % percent limits of iraqi specification no.5 / 1984 sio2 21.10 not available fe2o3 6.70 not available al2o3 5.30 not available cao 58.20 not available mgo 4.60 5.0% (max) so3 2.10 2.5% (max) loss on ignition (l.o.i) 2.89 4.0% (max) insoluble residue (i.r) 0.74 1.5% (max) lime saturation factor (l.s.f) 0.81 0.66%-1.02% main compounds al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 259 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.1.2 fine aggregate natural sand supplied from the al ekhaider region was used in this investigation. the results of the tests showed that the grading and other properties confirm the limits (iraqi specification no.45, 1984), all properties are illustrated in tables (2). table 2. properties of fine aggregate sieve size (mm) cumulative passing% limits of iraqi specification no.45 / 1984 10 100 100 4.75 90 90-100 2.36 76 75-100 1.18 67 55-90 0.600 50 35-59 0.300 17 8-30 0.150 3 0-10 material finer than 75-µm (sieve no. 200) 3.20 5% (maximum) so3 0.296 0.5 (maximum) c3s 25.40 not available c2s 41.33 not available c3a 2.71 3.5 (max) c4af 20.39 not available physical properties properties test result limits of iraqi specification no.5 / 1984 time of setting (vicat test) initial setting (min) 85 45 (min) final setting (min) 410 not available compressive strength (mpa) 3 days 18.1 15 (min) 7 days 26.3 23 (min) al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 260 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.1.3 coarse aggregate crushed gravel from (al-nba’ay) region with a maximum size of (10) mm was used throughout this investigation. all properties of the coarse aggregate are shown in table (3). the obtained results indicate that the properties of coarse aggregate are within the requirements of (iraqi specification no.45, 1984). 3.1.4 specifications of the metal and plastic reinforcement the metal and the plastic wire mesh, available in the local markets used in fencing of plants in gardens, were used in this study. these wire mesh used as reinforcement in concrete tiles, which placed in the tension zone of the tiles to have resistance to flexural strength. these wire mesh have square openings with dimensions of (10 x 10) mm. three patterns of each type of wire mesh were used in this study in order to study the effect of the shape of reinforcement on flexural behavior of concrete tiles, the types of wire mesh and its patterns are shown in figure (1). table 3. properties of coarse aggregate sieve size (mm) cumulative passing% limits of iraqi specification no.45 / 1984 37.5 100 100 20 100 95-100 10 54 30-60 5 3 0-10 material finer than 75-µm (sieve no. 200) 1.40 3% (maximum) so3 0.087 0.1 (maximum) (a): metal wire mesh al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 261 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1. types and patterns of wire mesh used in this study 2. description of the tested specimens three types of specimens were prepared in this study, the major one is precast concrete tiles with dimensions of (400*200*50) mm which conform the dimension of type (c) tiles as mentioned in iraq specification no.1107, 1987, in order to investigate the properties of tiles listed in iraq specification no. 1107, 1987 and they are flexural failure load, density; cubes specimens with dimension of (100*100) mm also prepared to determine compressive strength of concrete, and cylinder specimens with dimensions of (100*200) mm to determine splitting tensile strength of concrete. the tiles specimens were divided into three groups, the details and the number of specimens in each group is shown below: the first group consists of six tiles with the designation of (t1), three of them were tested at age of (14) days and the other three were tested at age of 28 days. the second group consists of eighteen tiles reinforced with three patterns of the metal wire mesh with the designation of (t21), (t22) and (t23), where these sub-groups consists of six specimens. the first three of each sub-groups were tested at age of (14) days and the other three tested at the age of (28) days. the third group also consists of eighteen tiles reinforced with three patterns of the plastic wire mesh with the designation of (t31), (t32) and (t33), where these sub-groups consists of six specimens. the first three of each sub-groups were tested at age of (14) days and the other three tested at the age of (28) days. the dimensions and details of the tiles specimens in the three groups are shown in figure (2). (b): plastic wire mesh (c): longitudinal stripes of metal wire mesh and plastic wire mesh al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 262 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. t21*, t31* t1* t23*, t33* t22*, t32* * this mark refers that the number of casted tiles is six. 4 0 0 m m 200 mm 100 mm 1 0 0 m m 40 0 m m 200 mm 4 0 0 m m 200 mm 1 5 0 m m 20mm 4 0 0 m m 200 mm 100 mm 1 0 0 m m figure 2. the details of tiles al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 263 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.3 mix design and mixing of concrete british building research establishment method (teychenne, 1997) was adopted in this research to design the ordinary concrete, which is used in preparing all tiles specimens with and without reinforcement. the details of mix proportion are listed in table (4). the preliminary tests show that the compressive strength is (18.7 mpa and 22.3 mpa) in age (7), (28) days, respectively, this test was conducted according to british standard (b.s.1881:116, 1983). whereas the test results show that the splitting tensile strength is (1.75 mpa, 2.1 mpa) in age (7), (28) days, respectively, this test was performed based on test method reported in (astm c 496 , 2011). concrete is mixed in a small laboratory drum-type mixer with a capacity of (0.05) m3, the mixing procedure was performed according to (astm c192, 2015). any residual particles of concrete from a prior batch were cleaned before using the mixer, then it was cleaned with a moist cloth to clean the blades and drum of the mixer. firstly the coarse aggregate with some of mixing water was added into the mixer before starting it, the mixer turns on and the fine aggregate, cement, water were added to the mixer rotate, the all ingredients mixing together for (3) minutes in the drum of mixer followed by (3) minutes rest, during this period the top of the mixer was covered with polyethylene sheet to prevent evaporation, then mix again for (2) minutes as a final mixing, the mixture was discharged from the mixer and the casting of specimens start. 3.4 casting and curing procedure the moulds used for casting tiles specimens were mdf wood with specifying dimensions confirming (iraqi specification no.1107, 1987). each mould consists of a bed and four movable sides, the sides were fixed to the bed with screws. the clear dimensions of the moulds were (400  200  50) mm. figure (3) shows the moulds used in the study to prepare tiles. before casting, all moulds were well cleaned and their internal surfaces were lightly oiled to avoid the adhesion of hardening concrete to them. all moulds were filled with concrete except the tiles reinforced by wire mesh were casted in two layers and placed the wire mesh in the one third lower of tiles. the tiles, cubes, and cylinders were vibrated by placing them on the vibration table and were covered with polyethylene sheets to prevent evaporation of water. after (24) hours from casting, the specimens were demolded and cured by placing them in the curing tanks which filled with tap water until the time of testing. 3.5 specimen preparation and testing after casting and curing of specimens until the day of testing, all cubes were tested with compressive strength machine according to british standards (b.s. 1881:116, 1983) , and all cylinders were tested with compressive strength machine to determine the splitting tensile strength according to (astm c-496,2011). the flexural failure load test of the tiles specimens was conducted according to the (iraqi specification no.1107, 1987). table 4. mixture proportion cement (kg/m3) coarse aggregate (kg/m3) fine aggregate (kg/m3) water (kg/m3) 390 1040 760 195 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 264 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 4. results and discussion 4.1 flexural failure load this test is one of the most important tests, which has been carried in the tiles, the specimen was fixed in the test machine to obtain a simply supported condition at distance (5) cm from each end and subjected to concentrated load applying on the center of the specimen provided by wood plate with width (10) mm, as shown in figure (4), the load is applied homogeneity and continuously until the failure. the lower limit of flexural failure load was (4.4 kn), according to the iraqi specification of the flag type (c) with dimensions (200*400*50) mm. figure 3. the moulds used in this study figure 4. test of tiles specimen al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 265 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. from table (5) and figure (5), it can be distinguished that the flexural failure load for all specimens confirmed the limit of (iraqi specification no.1107, 1987). the test results shown improving flexural failure load for all reinforced tiles comparing with control specimen without reinforcements. the percentages of increasing of flexural failure load relative to the control specimen in the age of (14) days are (5) %, (14) %, and (23) % for square, strips, and the specific shape of plastic wire mesh reinforcement, respectively. whereas the percentages of increasing are (18) %, (18) %, and (20) % for square metal, strips, and the specific shape of plastic wire mesh reinforcement, respectively. while the percentages of increasing at age of (28) days are (10) %, (17) %, and (25) % for square, strips, and the specific shape of plastic wire mesh reinforcement, respectively. whereas for tiles reinforced with a metal wire mesh with square, strips, and specific patterns flexural failure load is increased by a percentage of (33) %, (35) %, and (21) %, respectively. the cause of increasing in flexural failure load denoted to reinforcement which used to strengthen the tension zone of tiles by metal and plastic wire mesh so that this wire mesh worked to increase the strength of tiles to flexure. table 5. results of flexural failure load of concrete tiles tile type flexural failure load (kn) at age 14 days at age 28 days limits of iraqi specification no.1107 / 1987 control (t1) 4.4 4.8 4.4 square plastic (t21) 4.6 5.3 specific plastic (t22) 5.4 6.0 strips plastic (t23) 5.0 5.6 square metal (t31) 5.2 6.3 specific metal (t32) 5.3 5.8 strips metal (t33) 5.2 6.5 figure 5. flexural failure load at different ages al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 266 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 4.2 density the dimensions (length, width, and height) were measured in this test for each tile, and the average of the measurements from three different positions for each dimension was taken, forward the mass of each tile was measured by electric balance, and calculated the density by dividing the mass on the volume of each specimen (neville and brooks 2010),( neville, 2011). it can be noted that from table (6) and figure (6) an increment of the density of reinforced tiles comparison with control specimen, and little difference between density values of reinforced tiles. the increment ratios of density are (0.85) %, (0.89) %, (0.76) %, (0.93) %, (0.89) %, and (1.1) % for tile reinforced with square plastic, specific plastic, strips plastic, square metal, specific metal, and strip metal, respectively. there is a little effect on the density of tiles by reinforcing them with metal and plastic wire mesh and can be considered negligible, this behavior may be due to the small thickness of reinforcing materials relative to that of tiles, and little weight of clams comparing with concrete ingredients. table 6. results of density of concrete tiles tile type density kg/m3 control (t1) 2360 square plastic (t21) 2380 specific plastic (t22) 2381 strips plastic (t23) 2378 square metal (t31) 2382 specific metal (t32) 2381 strips metal (t33) 2385 figure 6. density at different ages al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 267 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 4.3 absorption an electric furnace was used for drying the tiles specimens for (24) hours, after that they were removed to cool in air and then the dry weight was recorded. the tiles were placed in a water tank, after (24) hours the samples were removed and the outer surface was dried with a piece of fabric to get the saturated surface dry condition, this weight also recorded for each sample to calculate the absorption ratio. the results of the water absorption of concrete tiles are demonstrated in table (7) and schemed in figure (7), it is directed that the water absorption for all reinforcement concrete tiles decreased as associated with the concrete tiles without reinforcement. furthermore, all water absorption results agree with (iraqi specification no.1107, 1987) limits (rate of absorption less than 10). the percentage of decrease for the plastic wire mesh (21) %, (26) %, and (19) % to square, stripe, specific respectively as compared to control tiles. however, the percentage of decreased for the metal wire mesh (47) %, (54) %, and (51) % for square, stripe, specific correspondingly as related to control tiles. that trend may attribute to the ability of both wire mesh reinforcement to control cracks distribution leading to diminishing the water absorption of concrete tiles. table 7. results of absorption of concrete tiles tile type absorption% (24 hours) limits of iraqi specification no.1107 / 1987 control (t1) 5,7 10 square plastic (t21) 2.3 specific plastic (t22) 3.0 strips plastic (t23) 3.9 square metal (t31) 2.8 specific metal (t32) 3.0 strips metal (t33) 2.6 figure 7. water absorption at different ages al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 268 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 5. conclusions the objective of this investigation was to assess the effects of wire mesh reinforcement on some properties of the concrete roofing tiles, which are plastic and metal wire mesh. conclusions depend on test results can be summarized as follows. metal wire mesh and plastic wire mesh can be effectively employed as reinforcement for the concrete tiles. though, the metal wire mesh reinforcement is more beneficial over plastic wire mesh reinforcement in regards to water absorption and flexural failure load. the better pattern of reinforcement in flexural failure load of the concrete tiles for the metal wire mesh is strips, square and then specific. whereas, the better pattern for the plastic wire mesh is specific, the strips and the square. in terms of durability, the water absorption test results set that both metal wire mesh and plastic wire mesh exhibited a worthy decline in the water absorption. that trend attributed to the ability of both wire mesh reinforcement to control cracks distribution leading to diminishing the water absorption of concrete tiles. the trend of the shape of the reinforcement of water absorption of concrete tiles is similar to that in the flexural failure loads, the strip's shape the best in the metal wire mesh and the specific shape is the best in the plastic wire mesh. the use of wire mesh reinforcement in the concrete tiles is not significant effect on the density of the tiles, the increase in the density of the tiles not more than 1 %. references 1. al-mashhadani, s.a., al-attar, t.s., al-khateeb, a.m. developing of concrete tiles, journal of engineering, vol.12, no.2, 2006. 2. astm c 496. splitting tensile strength of cylindrical concrete specimens, annual book of astm standard 2015. 3. astm c 192. making and curing concrete test specimens in the laboratory, annual book of astm standard 2015 . 4. british standards institution. b.s 1881, part 116. method for determination of compressive strength of concrete cubes, 1983. 5. darsana, p.r.a., jasheela, a.j.a., binuraj, p.r., sarma, j. development of coir-fiber cement composite roofing tile, procedia technology, 24, p. 169 – 178, 2016. 6. engel, r.s. and bekis, c.e. fiber reinforced polymer-grids for reinforced concrete, national science foundation center, june, 2001. 7. iraqi specification no.5. portland cement, central organization for standardization and quality control, ministry of planning, 1984. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 269 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 8. iraqi specification no.45. aggregate from natural sources for concrete and construction, central organization for standardization and quality control, ministry of planning, 1984. 9. iraqi specification no.1107. precast concrete flags, central organization for standardization and quality control, ministry of planning, 1987. 10. netlon. tensor grids in concrete applications, the civil engineering division, blackburn, december, 1988. 11. neville, a. m., and brooks, j. j. concrete technology, pearson, 2nd edition, 2010. 12. neville, a.m. properties of concrete, fifth edition, pearson, 2011. 13. sahu, s.k. and jain, j.k. effect of chopped glass fibers on the strength of concrete tiles, thesis, b. tech and m. tech (dual) in civil engineering specialization structural engineerin, rourkela769008, 2015. 14. shah, s.p. and key, w.h. impact resistance of ferro cement, asce proceedings, journal of structural division, january, 1972 15. thweny, z.a. using propylene–ethylene grid to improve the production of precast concrete slabs, eng. & tech. journal, vol.31, no.4, 2013. 16. teychenne, d.c., franklin, r.e., erntroy, h.c. design of normal concrete mixes, watford, u.k., building research establishment, 1997. template for academica science journal al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 496 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. study of using the crushed clay bricks with natural aggregate as unbound subbase pavement layer in segregated form lecturer, dr. ali abdulla abed, university of al-qadisiyah, college of engineering, civil engineering department. e-mail: ali.abed@qu.edu.iq assist. lecturer, mr. zaid abdul zahra mahdi, university of al-qadisiyah, college of engineering, roads and transportation engineering department. e-mail: zaid.mahdi@qu.edu.iq received on 7 august 2017 accepted on 31 october 2017 published on 15 january 2018 doi: 10.30772/qjes.v10i4.497 abstract: construction and demolition of buildings and structures are producing excess or waste material which is including concrete, brick, steel, etc. conservation and reuse of resources is a necessity in achieving sustainability across the globe, crushed brick could be safely added to crush rock blends in pavement sub-base applications with percent up to 25%. the experimental work was consisted of two groups of samples depending on percent volume of each material, each group samples have 6 different layering blends patterns prepared by spreading the pure materials in layers (segregated form) of crushed bricks sand (cbs) and natural aggregate (na), in addition to the two control samples and then experimentally tested to compare with the requirements of iraqi specification for roads and bridges. the experimental work was consisted of atterberg limits, sieve analysis, moisture-density relationship and california bearing ratio (cbr) tests. the results show that using of the crushed bricks as sand with natural aggregate as unbound subbase in segregated form is feasible and agreed with the iraqi specification requirements because the cbr of cbs was improved when blended with the na at all the patterns, the best pattern is that which containing three layers na and two cbs (60% na and 40% cbs by volume) and the na was at the top, then cbs in alternated sequence that improves the cbr value to 1.6 times compared with na control or 8 times of cbs control because the sporadic distribution reduces the effect of the low bearing material, in another words; collect the layers of the same material doesn't give best improvement. keywords: crushed clay bricks (cb), crushed bricks sand (cbs), natural aggregate (na), unbound subbase, segregated layers, california bearing ratio (cbr). introduction and literature review construction and demolition of buildings and structures are producing excess or waste material which is including concrete, brick, steel, and other building materials and products [1], the recycling and reuse of mailto:ali.abed@qu.edu.iq mailto:zaid.mahdi@qu.edu.iq al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 497 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. industrial wastes should be considered in geotechnical and pavement applications in order to generate sustainable solutions [2], [3]. the replacement of traditional gravel materials with alternative materials is increasingly preferred from both environmental and economic perspectives [4]. crushed clay bricks and roof tiles are among the best aggregates, for use in concrete are known have to resistance at high temperatures, and concrete with such aggregates performs much better than similar concretes containing granite aggregate [5]. limited researchers had investigated on the possibility of using crushed clay bricks as aggregates in unbound subbase materials applications and they included that is feasible for using in subbase applications. those researchers like: zakaria and rauf reported that, good quality brick aggregate in unbound condition has found to be satisfactory from strength consideration [6], poon and chan show that the replacement of recycled concrete aggregates by crushed clay brick further increased the optimum moisture content and decreased the maximum dry density and when the coarse crushed clay brick content increased. they show causes of that to the lower particle density and higher water absorption of crushed clay brick compared to those of recycled concrete aggregates, the subbase using crushed clay brick as the fine aggregate was less susceptible to moisture variations when compared to the subbase using recycled concrete aggregate as the fine aggregate. the use of crushed clay brick lowered the cbr value. a 4-day soaked period had a negligible influence on the cbr values of the recycled subbase [7], it was feasible to blend recycled concrete aggregate and crushed clay brick to produce a subbase with a soaked cbr value of at least 30%. aatheesan et al., found that crushed brick could be safely added to crushed rock (class 3) potentially up to 30% [2], and could be safely added to recycle concrete aggregate and crushed rock blends with percent up to 25% [8]. arulrajah et al., concluded that crushed brick may have to be blended with other durable aggregates to improve its durability and to enhance its performance in pavement sub-base [9]. arulrajah et al. (2013), evaluated the geotechnical and geo-environmental properties of five types of construction and demolition materials "recycled concrete aggregate (rca), crushed brick (cb), waste rock (wr), reclaimed asphalt pavement (rap) and fine recycled glass (frg)", they mentioned that "there is ability to improve the behavior of cb, rap and frg materials to enable their usage in pavement sub-bases by additives or mixed in blends with high quality aggregates", they find that limited work has been conducted on using crushed brick in geotechnical applications although there are several research works focusing on using cb in concrete mixture, concrete tiles and blocks [10]. the geotechnical properties of recycled cb had showed in some researches, like in arulrajah et al., and from their study on cb from the recycling site (typically may consists of up to 30% other materials) with a maximum particle size of 20 mm, found that the fine content % (6.6), cbr % (123-138), compaction modified density (19.82 kn/m 3 ) with optimum moisture % (10.7), and tri-axial test (cd) cohesion (41.1kpa) [9]. and mithaq albeer louis, et al., in their research worked on cb sand with the classification according to (uscs) was poorly graded sand (sp) and it is not plastic matter [11]. also arulrajah et al in their research, rca, cb and wr in particular are found to also meet the physical and shear strength requirements for aggregates in pavement base/subbase applications [12]. in addition to wijewardana et al had found the 100% recycled brick sample achieved a maximum dry density of 2020 kg/m3 and a cbr value of 113%. the blend of 50% crushed bricks and 50% gravel also satisfied the atterberg limit dry density (1779 kg/m 3 ) and cbr value (32%) [4]. and diagne et al., in their research results indicated that los angles abrasion of 100% recycled clay bricks and 100% recycled concrete aggregate were 36.8% and 29.9%, respectively [13]. other studies on cb with stabilizers were found to be viable for usage as pavement base/subbase construction materials. these studies like in mithaq albeer louis, et al. when studied blend the (rap) with cb sand and stabilized with cement and/or lime, concluded that increasing bricks sand increase the compression strength [11]. and mohammadinia et al in their research on using the fly ash to stabilize (cb) and (rap), the results of geotechnical investigation showed a considerable increase in mr and unconfined compressive strength of cb and rap [14]. this paper describes the technical feasibility on application of the crushed clay bricks as fine aggregate (sand) in road construction in segregated form with natural aggregate. this investigation involved making samples with laying the natural aggregate (na) and crushed bricks sand (cbs) sequentially and comparing the cbr results with the pure natural aggregate, in light of the economic and environment al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 498 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. objectives, this paper aims to use the (cbs) with easy method of construction to reduce waste material and conserve the natural one. 1. methodology the experimental work was consisted of two stages: first stage: the control blends samples were prepared to study the geotechnical properties of na and the cbs each separately for a comparison later, figures (1 and 2) show the materials. a. the natural aggregate sample. b. the molded sample. figure 1: the natural aggregate material. a. crushed bricks sand sample. b. molded sample. figure 2: the crushed bricks sand material. second stage: two groups of layering blends were prepared by spreading the the pure materials in layers, group (a) composed of (60% na and 40% cbs by volume), group (b) (60% cbs and 40% na by volume), different blends patterns of cbs with na were prepared for each group as shown in table (1) and figure (3), then the samples was experimentally tested to compare with the requirement of iraqi general specifications for roads and bridges. table 1: illustrates the experimental work blends patterns. layer no. (from top) blends patterns of group (a) blends patterns of group (b) a1 a2 a3 a4 a5 a6 b1 b2 b3 b4 b5 b6 1 na na na na na cbs cbs na cbs cbs cbs cbs 2 cbs cbs na na na na na cbs cbs cbs na cbs 3 na cbs cbs cbs na na cbs cbs na cbs cbs na al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 499 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4 cbs na cbs na cbs na na cbs na na cbs na 5 na na na cbs cbs cbs cbs na cbs na na cbs figure 3: samples of blends patterns. to evaluate these types and to find the geotechnical properties, the tests below was achieved: 1. grain size distribution analysis according to astm c 136 [15]. 2. liquid and plastic limits according to astm d 4318 [16]. 3. specific gravity and absorption for fine aggregate according to astm c 128 [17]. 4. moisture – density relations according to astm d 1557 using modified proctor method [18]. 5. california bearing ratio (cbr%) according to astm d 1883 [19]. 2. materials 2.1. natural aggregate (na): the natural aggregate was the ordinary subbase material used in the middle and southern region of iraq from al-najaf city quarries, graded as middle limits of subbase course type c as specified according to the iraqi general specifications for roads and bridges (scrb/ r6. 2007) [20] as shown in table (2). the plastic and liquid limits are 18.5% and 23.7 % respectively, the plasticity index was 5.2 and the maximum dry density m.d.d was 2.1 gm/cm3 with o.m.c 9.6%. the good gradation and presence of coarse aggregate lead to raise cbr, it was 45% at m.d.d. this result agreed with the iraqi requirements for subbase materials. the high percent of fines with high plasticity make good bonds but the displacement increase when loading. table 2: grade requirements selected granular material (scrb. 2007/ r6). gradation sieve size (mm) percent of passing type a type b type c type d natural aggregate 75 100 50 100-95 100 25 95-75 100 100 100 9 65-30 75-40 85-50 100-60 67.5 4.75 55-25 60-30 65-35 85-50 50 2.36 42-16 47-21 52-26 72-42 39 0.3 18-7 28-14 28-14 42-23 21 al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 500 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 0.075 8-2 15-5 15-5 20-5 10 cbr % (minimum) 45 35 30 20 2.2. crushed bricks sand (cbs): the crushed bricks sand brought from waste clay bricks then crushed to pass from sieve 9.5 mm. figure (4) show the grain size. it's classification according to the unified soil classification system as well graded sand (sw) and the group index (0). it's classification according to aashto method as a-3. using of the crushed clay brick as the fine aggregate (sand) was low susceptible to moisture variations as shown in figure (5) that’s also mentioned in poon and chan (2006) [7], it have the higher optimum moisture content due to the lower density and higher water absorption, this make the cbs feasible using in layer exposed to moisture like in subbase. the properties of cbs shown in table (3), cbr value was lower whan it's value in na due to the gradation of cbs as sand (without coarse aggragte) and be not cohesive non-plastic material and became loose (without bonds) under moisture. the cbr value is high as compared with the origin materials of bricks (sand, clay, and silt), becuase its firing to 1000 0 c and dehydration and fusion process make it turns into a dense glass material to produce cohesion and hardness [21], the firing process is containing oxidations of caco3 , mgco3 and fe2o3 also changes in chemical composition like in kaolin (2sio2.al2o3.2h2o) to sio2 and al2o3 then to produce new composition. the chemical composition of bricks al2si2o5(oh4),sio2 plus fine stones [22], the presence of alumina in raw materials of bricks give it the strength [23]. in light of the iraqi specifications requirements; the cbr value doesn't agreed with the limit of the subbase course when used alone. figure 4: illustrates the grain size distribution of crushed bricks sand. figure 5: the moisture-density relationship of crushed bricks sand. al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 501 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 3: illustrates the properties of tested crushed bricks sand. fines content m.d.d gm/cm 3 o.m.c % cbr % plastic limit p.l % apparent specific gravity water absorption % 1.6 % 1.58 20 9 np 2.86 6.3 3. results and discussion 3.1. for blend patterns of group (a): as shown in figure (6), the cbs bearing ratio was improved and the whole cbr results within the requirements of the iraqi specifications for subbase type c. the cbr values were decreased from 72 % (at pattern a1) to 30% at pattern a6 because of the collection of two or more adjacent layers of the same material, the characteristics of that substance will be shown. in contrast, when spreading the pure materials in alternated form layers consecutive na then cbs , this will show the best results. so the best pattern was a1 which also because the na at top which has the higher bearing ratio (due to presence of the coarse aggregate and fines bonding) covered the cbs layers (which was the loose and weak material), and the minimum thickness of the cbs made the load transmitted to the below na layer which carried and supported, when compared bearing results of this pattern with the control blends, it is higher than the na sample (by 1.6 times) and cbs (by 8 times), the sand works as leveling and reparation gradation the segregated particles from the previous spread layer also it is reducing the vertical displacement of the pattern due to its non-plasticity property in it's fines, and also cbs has higher cbr than ordinary soils fines with less susceptibility to moisture. the cbs at top layer reduced the bearing ratio due to it's charecteristics of not cohesive non-plastic material and loose (without bonds) and the less bearing without covering as shown in pattern a6, this cbr value was the least among all the patterns results not just due to presence of the low bearing (cbs) layer at top, but cbs didn’t be between the na layers to improve the na layers by reducing the displacement, also lower than the control na sample, this cbr was improved for subbase layer to 3.3 times as compared with the cbs control sample. figure 6: the cbr% test results of group (a) blends patterns. 3.2. for blend patterns of group (b): as shown in figure (7), the cbs bearing ratio was improved and the whole cbr results within the requirements of the iraqi specifications for subbase type c except samples b4 and b6 they are within the type d, the cbr values were less than those in group (a) due to the high percent of low bearing material (cbs) opposing na in spite of reducing the vertical displacement. the best cbr result was 45% at pattern b1 then began to degrease to 26% because of collecting two layers or more of same material especially the na (due to displacement). also, the low values due to existence the cbs at top layer (loose, low bearing al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 502 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. material and it's grade as fine aggregate). the next best pattern was the b2 because the top layer was na which covered cbs. although the pattern b1 consists of just 40% na with 60 % cbs, it gave the same cbr % value of control na sample because of reducing the displacement. and when compare it with cbs control blend, the cbr was improved to five times because the na improve the cbs. this pattern test result satisfied the iraqi requirements for subbase course depending on cbr (it is comply with type a). the cbr result of pattern b2 was 34.7% at 0.1 inch penetration and decreased at 0.2 inch to be 25% because the load had transmitted to the under layers which was lower bearing and high thickness of cbs allthough the top layer was the na. this cbr value is larger than it's in pattern a6 in spite of increasing the cbs because the na at top carry loads more than cbs. although this pattern has the same percent of cbs like in pattern b1 but the cbr is less due to thickness layer of cbs (collected). also, this cbr result is lower than the control na sample due to presence and thickness of the low bearing cbs without spreads the na between them. the cbr of b2 was improved for subbase layer to 3.7 times as compare it with cbs control sample. figure 7: the cbr test results of group (b) blend patterns. conclusions construction process of roads trending to use crushed bricks in pavement layers which is leading to study the feasibility of these materials, this paper studied using of the waste bricks crushed as sand in unbound layers and used with natural sub-base materials in segregated form to produce such study patterns, and its concluded that: 1. the density of cbs is low susceptible to moisture variations as shown in moisture-density relationship test figure (5), it have the higher optimum moisture content due to the lower density and higher water absorption that is make it feasible for using in layer exposed to moisture. 2. the cbr result of cbs alone was less than the limit of subbase course because it is not cohesive non-plastic material and became loose with moisture. 3. the use of crushed bricks as sand with natural aggregate as unbound subbase in segregated form is feasible and agreed with the iraqi specification requirements because of the cbr of the cbs was improved when mixed with the na at all the patterns. 4. the best blend is not just with increasing the material which has the high mechanical properties, but in pattern of its distribution within the depth and its position from the top layer. so, the best blend pattern is (a1) which have cbs spread between na layers and na at top. this had improved the cbr value compared with control sample of na, and it gives supporting to the cbs layers. 5. collecting layers of the same material together doesn't give best enhancement, and the sporadic distribution reduces the effect of low bearing material like in blend patterns. 6. as compared with the control sample of pure cbs, the cbr value is improved when blending 60% of the cbs with 40% of na in patterns b1 and b2 to 5 and 3.7 times respectively, while in blending 40% of the cbs with 60% of na, the cbr is improved to 8 times in blend pattern a1 (compared to the control sample of pure na is improved about 1.6 times) and increased to 3.3 times in pattern a6. al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 503 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. recommendations 1. it's recommended to use the crushed bricks in road subbase layer construction, when use it as sand in unbound layer in segregated form with natural aggregate and it's recommended to use the blend pattern a1 in mean spreading cbs between na layers in the series of na layer above cbs layer (consecutively). 2. it's recommended to use this method of spreading (segregated) instead of mixing the two materials together for easy in the execution. 3. for future studies, it's recommended to use the recycled concrete aggregate instead of the na or treat the cbs with cement. references 1. worksafe victoria, "recycling construction and demolition material", guidance on complying with the occupational health and safety (asbestos) regulations 2003, (2006). 2. aatheesan, t., arulrajah, a., bo, m. w., vuong, b., and wilson, j. “crushed brick blends with crushed rock for pavement systems”, waste resource manag., 163(1) (2010), 29–35. 3. a. choudhary, j. jha, k. gill, s.k. shukla, "utilization of fly ash and waste recycled product reinforced with plastic wastes as construction materials in flexible pavement", in: geo-congress, (2014), pp. 38903902. 4. wijewardana, a d e de alwis. s a d dilini lakmini and k m l a udamulla, "the potential of using recycled bricks as a material in sub base applications", m a c d sri lanka association for the advancement of science proceedings of the 71st annual sessions, 2015, part i. 5. khalaf, f.m.; devenny, a.s. "performance of brick aggregate concrete at high temperatures", j. mater., civ. eng., 16, (2004), 556–565. 6. zakaria, m and rauf, a.f.m. "behavior of brick aggregates in base and sub-base courses journal", the institute of engineers, bangladesh, vol. 14. (1986). 7. poon, c. s., and chan, d., “feasible use of recycled concrete aggregates and crushed clay brick as unbound road sub-base”, constr., build. mater., 20, (2006), 578–585. 8. arulrajah, a., piratheepan, j., bo, m. w., and sivakugan, n., “geotechnical characteristics of recycled crushed brick blends for pavement sub-base applications”, can., geotech., j., 49(7), (2012a), 796–811. 9. arulrajah, a., piratheepan, j., aatheesan, t., and bo, m. w., “geotechnical properties of recycled crushed brick in pavement applications”, journal of materials in civil engineering © asce j issn 0899-1561, 23(10), (2011), 1444–1452. 10. a. arulrajah; j. piratheepan; m. m. disfani; and m. w. bo, m., "geotechnical and geo-environmental properties of recycled construction and demolition materials in pavement subbase applications", asce © 2013 american society of civil engineers, the journal of materials in civil engineering, vol. 25, no. 8, issn 08991561/(2013), pp. 1077-1088. 11. louis m. a., sultan s., m.sc student mahdi z., "structural evaluation of cold recycling reclaimed asphalt pavement (rap) blends", journal of engineering and development, september, issn 18137822, vol. 18, no.5, (2014), p.p 246-263. 12. arulrajah a., mahdi m. disfani, horpibulsuk s., suksiripattanapong c. , prongmanee n., "physical properties and shear strength responses of recycled construction and demolition materials in unbound pavement base/subbase applications", construction and building materials, 58, (2014), 245–257. 13. diagne, m., tinjum, & nokkaew, k., "the effects of recycled clay brick content on the engineering properties, weathering durability, and resilient modulus of recycled concrete aggregate", trans., geotech., j., 3, (2015), 15-23. al-qadisiyah journal for engineering sciences vol.10 , no. 4 issn: 1998-4456 page 504 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 14. mohammadinia a., arulrajah a., horpibulsuk s., chinkulkijniwat a., "effect of fly ash on properties of crushed brick and reclaimed asphalt in pavement base/subbase applications",(2017), journal of hazardous materials, elsevier. 15. astm, " standard test method: c136-06: "standard test method for sieve analysis of fine and coarse aggregates", american association of state highway and transportation officials, 444 north capitol st. n.w., suite 225, )2006), washington. 16. astm, standard test method: c 4318-05: "standard test methods for liquid limit, plastic limit, and plasticity index of soils", american association of state highway and transportation officials, astm international, 100 barr harbor drive, po box c700, west conshohocken, (2005), pa 19428-2959, united states. 17. astm standard test method: c 128-04: "standard test method for density, relative density (specific gravity), and absorption of fine aggregate", american association of state highway and transportation officials, 444 north capitol st. n.w., suite 225, (2004), washington, dc, united states. 18. astm standard test method: d 1557: "standard test methods for laboratory compaction characteristics of soil using modified effort (56,000 ft-lbf/ft3 (2,700 kn-m/m3))", astm international, 100 barr harbor drive, po box c700, west conshohocken, (2003), pa 19428-2959, united states. 19. astm, " standard test method: d 1883-05: "standard test method for cbr (california bearing ratio) of laboratory-compacted soils", astm international, 100 barr harbor drive, po box c700, west conshohocken, (2005), pa 19428-2959, united state. 20. scrb, state corporation for roads and bridges, "standard specifications for roads and bridges", (2007), design and studies department, ministry of housing and construction, republic of iraq. .بغداد للنشر التقني دار . االولى الطبعة ,0991)ه",االنشائي المواد, "العالي عبد وجابر،سعيد عبد يوسف المجيد، بدبشير،ع جالل سرسم،. 21 22. groover, m.p., “fundamentals of modern manufacturing, material processes, and systems”, 2nd edition, john wiley & sons, inc., 2002. 23. ryan, w., "properties of ceramic raw material", 2nd edit. pergamon press, new york, (1978), pp113. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٠ ��� أ����4م "� e( � ا���اe(3 f�f ���و�� ا��gh#-ن���(�� �?%�� 2�#= ���9 ��� �#�� �#� ��* ���� �� ��#� ���#� 8���*+� ���� ����#.� ���#� 8 ���*+� ���� ��#� ���#� 8���*+� ���� ���*= ��� � ��� ����*#���� ���*+� ��� � ��� ���*= ��� �-!�� : �*�'��8 ����0� 4���� ��*��� 4�1 ��"����� ��#3% �0�� l(��� �+%� – *����0 ��+(% �% ., ����0�� ;./) o�0d� ����0�� (7%0�� �/�� �� ��'c* ��0'� ��"����� ?6�� �"�+, �# =c���� ����0�� ���� �� )5.5% ( ���* �*�%� @��(%�� ��'�% �� 7%0��(vortex technique) . o��0d� ����0��� �h �% �/ �� ��& �(% ���%7�� b���, �% l�( !��c'�� 4���� ���%7� �/��+(%* ��' �� ���*� !" �����%��� ����* j* �"�g�� ���( ��� '1* k 0�� �'*�7* ?�c'�� �"�0�* �0��� ��(�� � �9�%7� . , &(*�� <6��%'�� � 4�� ��*��� > �% �����%��� ���� �" @�.�* ;i18 j*�&�� � >8 ��c ���( !" � c� 4���� � �� 4�18 ��'� o�0d� ����0�� ���( !". ��"�m� � �� أ��� �م���ل ا���" ، : ا��)��ت ا� ، d +ا��اآ��-آo� ن ، ��اد�� � . effect of graphite on wear resistance of aluminumsilicon alloy saad hameed najem amar jabar badr aseel hadi hamza babylon university alqadisiya university babylon university materials department mechanical department materials department abstract this research deals with studying the effect of graphite on the wear resistance of aluminum – silicon alloy. firstly this alloy (master alloy) is prepared using casting method then graphite particles added in weight ratio (5.5 %) by using vortex technique after that the master alloy and composite material casted in dies and prepared for sliding wear test , wear test was made under different conditions of applied load , sliding distance and surface roughness at the room temperature. the results show that wear rate increases with increasing any of the above conditions, also the composite material show higher resistance wear than of master alloy. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧١ �����"� nomenclature: ا����ز ا� ρ = �� ا�� �+�cآgm/cm3. m = +( ا���اء �� ا�� ��oآgm. =v1 �� د ا���z�( 4 ا���ء�fcm . =v2 �� 4 ا���ء )�ون ا���fcm . m∆ = ��oا�� )+ � yoا�gm. ρ = ا���دة �+�cآ ���vogا��gm/cm3. a = � � �2س ا���oا� �f�g�cm2 . l = �+�g� ا��%�ق cm. ���.�� :introduction j�'h8 � ����1 �*h(�� ��� � �h�7 ��9h�*� ��. �*� ��0 '��� ����� %�� � � ��� �� %% ��0�0d� �*��� n�*7 @�%�%* �#�8 *8 � (� ��* �� �� <� � c�%�% �*� =�%', 4�, ���(�� �c�� �.� �� j��% ��%�'*�� 1 j�%7%�����%��� �*��]smallman and bishop ,1999. [. !' ���� o�0d� ��. �����%��� �*��� ,)mmc ( ��. �(�h8 ��' �� *8 ��������0 ?6�� � �*����* � � ��0�* ���� 7%0� !����� �'*���� ����� ��0� @�.* ��9%���� ���* 4���� ��*���. ;./ ��7 @�.� �� ������%���*��� �6� � � ��� !" �� ���%�� @6��0�� *8 ��' ���� �h�7�� ����� %�� �. ������%��� �9h%� ��* *�'��d� � o�0d� ��.� !��(�8 �0��� ��c 5� a �* @��%(� �����* ����1 4�� ��*���� � (%�� $�* 4�1 ��*�%�� ?6�� � -��*�% * � �*�'��d� @6��0 5� �'���� .�0�� , ������%��� ;.�� !�*�*����%�� @*?� ��� � �'���� �.�� ���1d� � � ��� @��'/* �#(���� � � ��� . ������%��� n7% !%�� ���� d� ��28 �" @�. 5�* �*��� o'��% 4�1 �" c��% �*�'��d� � o�0d� ��.) ��*�%�� �� 5�c*% ��&%'�( ]bolton , 2002. [. 1 �� 4�1 �#(���� ��=�%'8 �#�% !%��* ��"����� � ?6�� �+��� �*�'��d� � o�08 ��. ������%� ��h ��c��.@6��0� k��' �� � ��'� ��� ��� c�%�� 4�� ��*��� @�%�% �*��� ;./) *���0 �*�'��8 ( @6��0* �*��� ����* o�('�� .�*�'��d� ������%� ���*�0� ,y � ��%'8 ��"��� 6��� !" ���(�� �� 7%0�� s�g �* �c� �� �����bush ��7+��� j'�1c* pump impeller . ?6�� ��+% ��8 � ?� 1 @��'/* !%��* ��"�����* �*�'��d� � �6� ��� �� �%�� ������ 4�1 ��g%�� s�g� �*�'��d� ����0 ��h'� !" ��"����� ��"����� ��% s"�� ��0% 8 ��� .����0 ����� ��"����� ?6�� k 0 bi !/ �'�� ��0�6��� ���� �� . �*�'��d� 5� bi �� �� �� �� �%�� 4�1 �%�� ���� �� ;./ 8 �� 8 l�( . ��* ���'�� �� � 7%08* �� �%�� ������ �0(%� ��"����� bi ���� o�('�� -�"����� ?*(0�� k��' ��+%� jh%% ���� �� ;./* � ��h'����]kaw,2006. [ ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٢ i7�� �� 7%0� 4�� *#(���� 3�� ��" o�('�� *8 ���'��� bi �� �� 7%0� � �2����*)stirring ( ��+%� ����0�� �+ ��"����� ?6�� � ��� o3� � ����]joues ,1975[. � ��0�* ������%��� ;.�� @��%(��* @(�� n�*7� ���� ��9h� .@��'�" ��7d� ��*'0�� !" $�*% =�%'a � ���� ���� 7%0� ��c !��%���* ����%', j�� s97 s�g� �� ���%�� ����0�� ?� � ������%��� ;./ �1�'h�� ��0�*�� ]budinski and budinski ,(2005). [. �*�'��8 ����0� 4���� ��*��� 4�1 ��"����� ��#3% �0�� */ !��(�� l(��� � j ���– 0 *����. 2(� experimental work: ا���7$ ا�( �����%��� ����* o�0d� ����0�� ��+(% @#�' ������ ��a�� ��0�0d� �*�'��d� ����0 ��+(% �%)master alloy ( l(��� �./ !" �� 7%0��� �����0 !/*)al – 7.4% si – 1% mg ( !��*( ��h �% .,)4.3 kg (� �*�'��d� � !�'�%)99.99 ( �h% !6����� �" !" 4�, $%���( ��� )1200 cº (*� �� 7%0�� '�� *�d� � ��� ��%�0 )7 kg ( ����( ��� '1*)750 cº ( �9�%7� )�0 *. i7 �� 7%0�� �0'����� s�g� ���� �7 �%�*)1260 – 108 ( �* / ���� ��+ '1* � ��gh 5 � 5+* �% �*�'��d� ���h'� �*��'��d� �� ?6��� �7� �'�� 4�1 �� �*�0�'g���* *���0�� *��'�%)99.99 ( ��# �7�� ����1 b�'#8 =c���� ��'*�� !%�� ���* �� c��� !" (��� ��0'�� �0( ��%"�+,* �� =c���* �7�� ��%0�)5 – 3 ( ��h�� � ���� !" ��h'��� ���� �h �%� �/ �� ?6�� . 0�b ��� �c�+� !%m� ����� 4�1 ��% bi �� ����1* o�('��� ;bi �% o�0d� ����0�� 4�, ��"����� �"�+, ��� electroplating engineering handbook,vol.14, published by cbs,1987.][: ���.,)13.8 gm( -)69.2 gm( -)gm 20 ( �*� *h�� ��� � * ��6���� o�('�� ��%���� �) ���*� k�� ( ����� ;i18 ����(��� =c�% �# �'�� 4�1 i� � ���� b���� � ���� !" !��*%�� 4�1 �*� *h�� �0�*� �/* �"�+, �%� �/ �� ��)40 ml ( 4��, � ���� b���� � ���� j�+% �# <%�'�� <�c��� 4�, ��/ ���*9�� �� � (�* �%� � ���� b���� !6��'�� <%�'�� *�� l�(� <�c��� .�� �"�+, �% @�. )75gm ( ���(�� *. ��"����� � !���(��)63y105 ( ���0�% o'��% ��+� ����� �1�0 �� ����%0�� �7�� �%* ;i18 ��7�� 4�, *����� �"�g�� ���( ��� � ��% �������* ��"����� ?6�� 4�1 o�('�� . � �*��� k���% �% �/ �� k���% ?�* �i7 ��� � !6����� �" !" ��9�9�% �%* ��%�'�� �'����� �.78*50ºc �� 12�1�0 . ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٣ ��� ���� ?�#�� ��a�� !��*( ��h �% �* �9�%7� �c*3� ���� �% �% o�0d� ����0�� ��+(% ��)4.5 kg ( ����0�� � ���(�� ��� '1 ��h�� ��*&'� !" o�0d�)750ºc( �* � >.�� i7�� �� 7%0�� ��h'��� ���� �7 �%* �1�0�)420 rpm ( * (� !/* ����0��� �h�7�� ���h�� $�� ���(�� 4�, �*h*�� �(�)630ºc ( �% !%��* �*�'��8 ����0� >���(�� c�*%�� 7� �0( �/ � (%– *����0 ]metals handbook, vol. 8 american society for metals, metals park,ohio,1973.] �% !%��* ��"����� ?6�� �"�+, �/ �� �% 4�, ���0� ��'�70%)400ºc ( �/�� �� ��'c* ��0'�* ?6�� �� k 0 4�1 *�*��� ��* ��� � n�7%�� s�g� )5.5 % ( 4�, �9�� ���( ��� 5"� �% @�. ��)800ºc ( ��*)20 min. ( ��� �7�� ����1 ����8* � �h� �h�� ����1 ��%* �����%��� ���� !" ��"����� ?6�� � o'��%�* �&%'� 5�c*% 4�1 �*h(�� ��+� 4�, ���0� $'�70% �% !' �� ���� !")250ºc.( � ا�(��4ت�j # �اآ�� b�0 40 ��� ���h2ل #�" ا�� ��ت ا�]ز�� و�� .4 oس وا���دة ا��� bا �� �gآ] �� ا� � u20 ��( �اء اzإ�� رات #���op� . w26�� d��vo � )��3آ� إن أ)��د # ��ت ا��opر ا���" ه( ذا0�� ا�o( اnو�� ا��� �b�( � ا��b 10mm (]elmadagli and(و�jل ) 5mm(أ�����ي و��g2ب ا��f �+�c 1 آ��d ا�� ��ت ا alpas, (2006).] �u0و �� ر #���opاء ا��zإ k�i ت�� ا�� lb � u20 40 $4 )�� ذ� ��oا� � ��# � u2oا� � 1200، 1000 ، 600 ، 400 ، 220()� �voام ورق �� آ�ر) � ا�g � ��ن ذي �0ر�zت ( � ��# dn�zه� أ��( kgyا� � ��# dn�zوا���ء آ�� أ �� �2ق ا����g� � م +( ا�����vo ا�k�h �� ��ت ا�w26 ا�����ي +�t وا 4 ��0 � ��# kآ � ( �p�gاء ا�����( l 6�oم ���2ل وا��vo �ى أ�� ���� � ا9\��ر +�� اpوأ k�p أو graff – sargent �� ن��o84[ وا�� ml h2o , 15 ml hno3 , 0.5 ml hf , and 3 gm cro3[. y"�ب آ�f�a ا�(��4ت �و����( �g���fس oان ا��%��� � �b��� �i q���n ����س ا�����زن )�اj ����# 1���2ا�� )���+ �����o�ت ا������� ا�� ����+�cآ d�g���f (sartorius bp 301 s) ���i�( k���n )±1mg ( ��� z�zا�� ز�b� ��:k داk�p ا t �� � آ��bم ا����ء ا����vo� وا �� :]]al-ammar , 2008وd�gf ا����# �+�c � �� [pل ا����د�� ا~0 � ml .( 100(��ر�z ذات (1) 2m�jا� �&7���� j zا� ��ه� )� �voام ���n�h0 40و ��(� ����ت ا�� ��ت آ�� ذآuf ��+ ):�uا� ������( �n�hoاء ا��zض إ�y� � �س وا���دة ))1ا�6�c وp ):�,)400x ( �) ا�h���( ^ة ��0 bا �� �gا� �� k�� �n� l,�n ا��� � ا���� �اآoا����. 21 vv m − =ρ ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٤ k ا�(��4ت � ���c: س��> �اء #�� � ا�o�� 4 ��� ��ت )� �voام ورق 0�� l�ov� 4 ا���ر�zت i 4�0 ��س zت )�� أن 40 إ��� ا�� lb� ���s�p ���svس ا�� i ز��z ام�vo د���رآ( ا�h�^ وi 40 ��س ا����s�v ) taylor hobson(و lb ا���ص ا���vogم )� �اءات ��� �� ا�i اءات)���ل .]ث� t ا����sv ��83 ا���o� 3pة وا�fا�. e( <��س �(�ل ا� � ( �+�6hا�� k�# 40 1 f س� س ���� � )�����o آ/ yoا� � �ام �0�vo �36 ا��opر ا���" أ��%�)i ا���ف �( �ى و)��#��oد #�pأ ��z �� � 2bgا� ���svا��%�ق وا� �+�gو� t�gا�� k�2وا� ��z �� "ا����د�� ���ل ا��� " :] .ivkragelsky, dobyehin, vskombalov, 1982[ا~0 � ) 2( la m ρ ∆ wear rate = (pin-on-disk)ي 0�0 ���� ا������gر إ���" ا�����ص وا ���voم ����3ا ا�����opر z����ز i ���س ا�����" أ��%���i( ذ � (astm)وا�����j 4�h ���ا�6pت ./0 d20 ص ا��وار��ض ا��h2ل #�" ���f ا�e�[o ��) � ا�� �� وا��y� ��o(�. �� دورا� �#�� و��# 4o�0 �� ���k ا�2�آ�� ��� k��f(1370 rpm) #���دي ، و���onن ا�����ز ��� ��2�ك ذي � o�f� ، ا�����f اbو�" + 4on �� ��k ا�2�آ� �� ا��2�ك )�ا �b ا����ة ا��c0 40 )o o�� ا��2�ك إ�" ا���ص #�" � 2�آ�� ���ع �� k�i�� ام%�fو y �#(v-belt) آ���)����0ن ا��fه�� � �o]م ا�2 y� �# d�o�. (�oا� )b� إ��" ا�����د ا�� �ى ������ ، أ�� ا�����f ا���c � k�� ��uoo+ ا�2�آ� �� ا����د ا�� b( إ�" ا���pbص وا�ه3ا . �د ا���# d�c y ا�� $ �� yon��� )+ k bog� ^b�� ي #�" ذراع ذي�o2n 9,�+� إ�" إن ا����ز�((holder) إن ���# y + �� ا�� d �co� � ا��� $ �fا�( bi(5.5 mm). �c>�4� result and discussion :ا�lm��4 وا� $��� <��)�� ا�� �gا� � ( � j�oا� � �(�i � g2o� ت�� �f � vg0 )�6 وه�ov� ق�j ث[. d��vo �� ا��b� �م وا���ا+ d ا �ا ����n y" #�" . ا���ا+ d وj]ء ا���ا+ d )����2س وإ,�+� ا��y� g �م cن آ�+ d +ا�+���f )6 #�م vg0 � ا�� �ة وا�3ي )�ور��n 8ن #�:�� ر: g � +( ��0م )� � �f ��ت ا���ا+ d إ�" داkp ا�h�ا�� �� �gا� lb y �#و ��h��� أ�� #�� � [krishnan, surappa androhatgi, (1981)[ و���ة �#� وا�fة)vg0 40)400ºc � ا���ا+ d إ�" wu[j]ء �f ��ت ا���ا+ ��u0 ���g+ d د�pل ه83 ا��2 ��ت و�0زk�s( ���n أ+4o0 4� �� ��� ku #�� � ا�b]ء and beech, (1990). [. g �y9,�+� ا�� ��g���( أ�� ��o�nم و� ���bا �� �g� )2bgا� �sا� k ��o� م�vogn y��+ م� �sن ا�� � j�oا� � �(�i �g2n y�/( م� g �yوف #� ا���� وا���+�oو� ��cا� w pر y�b ��u6� م ��دة� g �yا�� � #�(mn/m 760) أ�� ���c� �م (mn/m 559)ا�y� )2bg اki �� ا��b� �م ا���( +���s ا�y��� )2bg� g �م 8�f�� م� ���bر�� �^ ا��� d +ا�� k��n زاو�n ا���oس �^ ا���h�م ا��� ���c� م� g �yر آ�3$ +�ن ا����hا�� �zدر d +ا� ,delanny,froyen and derruyttere[�^ ا�� (1987)]. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٥ آ�f�a ا�(��4ت �س آ��d )�2ود bا �� �gا� �+�c2.74(آ gm/cm3 ((اآ�� +�� أ�oأ�� ا���دة ا�� ��( إذ ، �+�cا�� �� i )+ �,�6vت ا�� �س) %5(ه3ا ا���6vض �fا�( bا �� �gا� �+�cآ �� . )+ d +ا�و���n أن �n%ى ه3ا ا����hن إ�" و�zد ا�� ashby and jones, 2007.] [. e( � ا� �6 ا��")[ e(3 �(�ل ا��gh# �� �f[n 6�c2( ا�(gا�� k�2دي �^ ا��j k�s( � yon "1 إن ���ل ا��� f "�2�ا�� k � زاد k�2وآ��� زاد ا� t� �i�bوآ�3$ ا� ���vogع ا���دة ا����� ا����� ^uvn k�2ا� �kh2n ا��soر و�0زn^ ا�k�2 #�" ا�� �� وان ا���oل 0/. �svا� lbgا� ^� �� ��� e�[oا� lb lb ا���ص(ا�2�ار�n ا�����oة )�g� ا���ofك ) � ( y �# ك�2o0 ا�3ي وان ��0 k ذ�$ ه� �hfل ا����6ت wi ����0 #� اz9��د ا��g( )byu� q�bn . ا�lbg ا�� �( ا�� �� وه� �� k���� �� i �� ^+�n ��� ص��g0 t ا�k�2 وه83 ا�����6ت �g0� ا���oل z%ء �� lb ا�� �� إ�" lb ا�� دة ا��%ا�� �� lb ا�� �� ا���ofك ا�3ي )�ور�gn 8� ز�nدة �iة ا���ofك وا�n )o�7o #��� ز�nدة +( آ� � ا��� yg6� ص�وآ�o �� ���g�g ا���� �ت ا��3آ�رة أ#]8 +�ن ��f�g ا�e�[o . ا��]�lbg� e ا���ص إ�" lb ا�� �ار ��� n%داد ���ل ا���" �o �ف 0%داد )�]sarkar, 1980. [. إن ���و�� ا���دة �unأ k�sا� )+ �f[nو �� �gاآ�� ����" أ#�" �� ���و�� ا��oا�� ��g( dn%آ� k��0 ا���رة #�" أن � o +ا� �س f 1 إن ���2 ��ت ا��bا �ارة f � ��0 "دي إ�i0 )oا� � #��ا� �nار��pاp�� ا�2�ار�n ا���g#�ة #�" ذ�$ آ�����p � ا�2�ار�n وا���g ا�2 .[smallman ,bishop,1999[ا��ofك �i �� #�� ا�lbg ا�� �( ��� ��0 "�# �#�gn k ���ل ا���" gh#e( � �"��f اr=�rق e(3 �(�ل ا�� �� �f[n 6�cا��%�)3( ا� �+�g� دة�n%( داد%n "اء ، ق إن ���ل ا���%zأ k�o�0 ف� �آ� ا���ص f �nو+( )�ا �nد�p�6 أ�v� ص��ة �� ��دة ا�� �� ا�" lb ا���ص �yg6 وn�7o #� ذ�$ ا��hoق ه83 اzb%اء )lbg ا�� yp bgط +( ا��bp �� #�" ه ��داآ �� o� م�vogص ا��� lb ا�� ���sp z6v�0 ل��oا�� kpا�oو) �� �6( ���gا� l �. ���� ا���6ات�og� � uو ^b�o� k�s( kh20 ت���oداد ���ل ا���" . #��� إن ا��%n ا��%�ق �+�g� دة�n%(و ا���ofك ��� �n�( و�f[n ���gf +( ا�k�s أ#]8 و���n أن �n%ى ذ�$ ا�" ز�nدة i �� ا�kys ا����% �� �i k�iة �ار�n #���� #�" ز�nدة ���ل ا���" f �i�j "ا� )�n�20ل �0ر]halling, 1979. [. e( � :���c ا�" e(3 k �(�ل ا��gh# �� �f[n 6�cدة ���ل ا���")4( ا��nدة ز�n%( lb ���sp د إ�" ان��n $ذ� )+ ��gوا� �� ا�� lb ���sp ��o� i )oص ا��وار وا��1.708µ(ا�� m ( ��sp ص� lb ا�� ��ت آ�+� ، و��� آ�ن lb ا�� ���sp �� "�#��0ن أ �ف gz ^�o�0 ��ت ا���دة و)����o( 0%داد آ� � ا���دة ا������o )�g� ز�nدة در�z ا�2�ارة lbgات ه3ا ا�io� ن�+ sا� � ��0 ��g0 ة� pbوه83 ا � +��ات ه�ا: � و��0 �pواbا �g�0 "دي ا�in ��� ك��ofا� �� o� 7o�n )oق وا��� وا�3ي ���n ا o�yz�o �� ا����hن ].#]elmadagli, perry and alpas, (2007)��� �hfل �bf �n��0م ا���" �n� إ�" ��دة ا�� ��i ص )��ن��ة و��0ن lb ا���ovا�� �� ا�� ��o�( kp�2ا� . �� l,س آ�� وا� bا �� �gاآ�� ��0ي ���و�� )�" أ#�" �� ا��o6 اإن ا���دة ا���c� )4 ( ��6� وا��g� +( ذ�$ آ�� ا �ارة ا��ofك �i �� #��� ا��lbg ا�� ��( ���� i�nدي f � ��0 "دي إ�i0 )oوا� d n%oا� "�# � o +ا�ه� �iرة ا��2 ��ت ا�� .إ�" ا��6vض ���ل ا���" conclusions:اr���9��4ت �س آ� ا��g �� اbإ�" vg0 � ا���ا+ d وj]ء8 )����2س وإ,�+� ا��y� g �م -1� j�oا� � �(�i � g20 "أدت ا� ��. 2��o+�cآ �� k��n س� bا �� �gا�" ا� d +ا� . إ,�+� ا�� �س -3bا �� �gا� �� ku+اآ�� ����" أ�oرة #��� ���و�� ا���دة ا���h( . ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٦ �اآ�� ����" ��nد ا�" و�zد �f ��ت ا���ا+ d ا���o�0 )o$ ا����رة ا�� -4oو�� ا���دة ا����� )+ ku6ا� ��n��0 "��# �� �� . �g6�� و)�hرة #��� �g0ه4 +( ا��6vض ���ل ا���" references:ا���sدر 1. r.e.smallman and b.j.bishop,"modern physical metallurgy and materials engineering" published by reed educational and professional ltd,1999. 2. w.bolton, " engineering material technology", third edition, amember of reed elsevier group, 2002. 3. a.k.kaw,"mechanics of composite materials" published by crc press,2006. 4. r.m.joues," mechanics of composite materials", scripta book company, washington d. c., 1975 5. k.g. budinski and m.k. budinski ,"engineering materials, properties and selection" published by prentice-hill(2005). 6. electroplating engineering handbook,vol.14,"nonelectrolytic metal coating processes" published by cbs,1987. 7. metals handbook, vol. 8 ,"metallographic , structures and phase diagrams", american society for metals, metals park,ohio,1973. 8. m.elmadagli and a.t.alpas,wear 261(2006)367-381. 9. j.h.al-ammar, "investigation the possibility of development the preparation of aluminum alloy 8009 by improving the manufacturing process, alloying elements and surface treatment, phd thesis , university of babylon, college of engineering , material eng. dept. 2008. 10. ivkragelsky, m.n.dobyehin, vskombalov, "friction and wear, calculation methods", translated from the russian by standen,1982. 11. b.p.krishnan,m.k.surappa and p.k.rohatgi, journal of material science 16(1981)1209-1216. 12. w.wu and j. beech, journal of the foundryman, feb.(1990)83-88. 13. f.delanny,l.froyen and l.derruyttere, journal of material science 22(1987)1-16. 14. m.f.ashby and d.r.jones," engineering material, an introduction to properties, applications and design" published by elsevier ltd 2007. 15. d.sarkar," friction and wear "academic press inc. (london) ltd.,1980. 16. j.halling, "principle of tribology" published by the macmillam press limited, london, 1979. 17. m.elmadagli,t.perry and a.t.alpas,wear 262(2007)79-92. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٧ (a) (b) ���� )1 ( 0#*���� ���+��� ��*�� )a ( @#�' ������ )b (��� ���� ?�#�� ���� )2 (����� ���� � ���� ���� "�� ��!�� . ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٨ ���� )3 (d1%*1 �b#��� ���� ���� "�� ��!�� . ���� )4 (e��� �*���� ���� ���� "�� ��!�� . 1-المقدمة: 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 العمود في العمارة العربية االسالمية (مضاميندراسة تحليلية لالبعاد وال) د. مهدي صالح فرج العتابي الجامعة التكنولوجية-مدرس/ قسم الهندسة المعمارية االختصاص العمارة العربية االسالمية والمحلية email: alfaraj200824@yahoo.com 2024آذار 27ُقبل 2022 تموز 2ُأستلم ملخص البحث: يعد العمود مسند قائم على األرض و يمثل الجزء المختص بالربط بين األعلى و األسفل وهما ثنائية لقاعدة التي تسند البناء المشيد فوقه، والصورة الشعرية جدلية تكسب المكان الخصوصية، فهو أشبه ما يكون با ويشكل العمود احد المفردات المعمارية في العمارة العربية ألعمدة تفترض أنها جزء من الهوية المكانية. اإلسالمية الجديرة بالبحث واإلحاطة بها واستكشاف جوانبها المختلفة كونها من الموروث الحضاري لألمة من الخصائص والسمات المعمارية ما يجعلها تتصدر تلك المفردات من الناحية الوظيفية والتي تمتلك والجمالية والتاريخية والروحية الدينية والرمزية واالجتماعية فضاًل عن األبعاد والمضامين األخرى. وقد نالت نماط المعمارية في البيوت اهتمام المتلقي منذ أزمان بعيدة، حيث أنها كانت تالمس فاعليته على مستوى األ في بقية األنماط و صريات والمباني التراثية قيوالقصور والمعابد والمساجد والخانات والحمامات واألسواق وال اإلسالمية ةالمعمارية فضاًل عن وجودها في تكوين النسيج الحضري العربي اإلسالمي. وكانت األعمدة العربي لتي أبرزها نمط العمود البغدادي )الدلك( ونمط العمود األندلسي. التي ظهرت من األنماط المعروفة و ا " في القصور والغموض في تحديد اإلبعاد والمضامين التي رافقت وجود العمود في المشكلة البحثيةوتتمثل " الكشف عن اإلبعاد والمضامين المختلفة التي رافقت نشأة العمود في هدف البحثالعمارة العربية اإلسالمية. العمارة العربية اإلسالمية وتوصل البحث الى االبعاد والمضامين التي تتمثل في البعد اإلنشائي والتاريخي والجمالي والروحي الديني واالجتماعي والفلسفي والرمزي والتعليمي والبيئي والحضري والشكلي والتعبيري والبعد الميقاتي فضاًل عن البعد التراثي. mailto:alfaraj200824@yahoo.com 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 the column in arabic islamic architecture (analysis study for dimensions and connotations) dr. mahdi saleh alfaraj alataabi lecturer at department of architecture university of technology email: alfaraj200824@yahoo.com abstract the column is considered as a support rooted in the ground and forms the part responsible for connecting the upper and lower level. it is a dialectic duality to provide the space with its required qualities .it is a base to support what lies above it and forms a poetic vision which hypothetically give the identity of the place .it forms a constituent in arabic islamic architecture worthy of comprehensive of its significance; and explore the various faces in the civilized heritage of the nation distinguished in its architectural character in terms of functional, aesthetical, historical and moral symbolism . in this content, the column provided a typological architectural expressions in palaces, temples, masjed, caravansaries , public baths , markets ...etc. which formed the total urban forms in the history of this land . the most significant type of columns in arabic architecture is the baghdadi ( the delegue) and andelosian columns . the “research problem” represent in the ambiguity and shortage, detection, dimension and connotations implications that accompanied a column in the arab-islamic architecture.the research aims to detect the different dimensions and connotations of which was accompanied by the emergence of the column. the results of research to reveal the dimensions and connotations of the different that accompanied the emergence of the column in the arab islamic architecture, which is the connotations of structural, historical, aesthetic, spiritual, religious, social, philosophical and symbolic, educational, environmental and urban, formal and expressive content timer as well as the connotations of heritage. :(introduction) المقدمة عن أي مفردة من مفردات العمارة العربية اإلسالمية وفي مقدمتها األعمدة وذلك من اجل أن الحديث أغنائها والكشف واإلحاطة في جوانب الغموض والنقص التي رافقتها تعد واحدة من والواجبات التي يضطلع ك المدارس التي تنتمي لتلك الحضارة التي نعيش في ظهرانيها بها المعماري الذي ينتمي لهذا التراث أو إلى تل mailto:alfaraj200824@yahoo.com 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 على مستوى الموروث المعماري أو حيث تضرب األعمدة أطنابها في عمق الحضارة العربية واإلسالمية سواءً و الروحي حيث يؤكد ذلك الكثير من األمثلة الموجودة في الحضارة اآلشورية أالثقافي واألدبي واالجتماعي مال األعمدة والتيجان وفي أماكن متعددة وبأشكال متنوعة منها ما عثر عليه في مدينة نينوى وهي على استع تحمل السقيفة وترتكز على أعمدة خالية من التيجان تتقدم مداخل القاعات وهكذا الحال في مدينة بابل التي وفي مدينة الحضر العربية استعملت فيها أعمدة اجرية تتقدم الرواق الذي يحيط بساحة الملعب الرياضي، وفي المعابد الصغيرة المنتشرة األواويناستعملت األعمدة الحجرية بكثافة في أماكن متعددة، أبرزها واجهات وتشير المصادر التاريخية إلى أن العرب قبل اإلسالم في جميع أرجاء المدينة وهي ذات طرز مختلفة. ان قصور العرب دنية بهيئة منفردة أو مندمجة بالجدران ، منها ما ذكر استعملوا األعمدة في مبانيهم الدينية والم والقصر في مملكة الحيرة ومنها قصور الخورنق والسدير)قصر الثالث قباب( وقصر العذيب والصنبر (،اصبح عنصر العمود سائدًا 64،ص7891االبيض وقصر الزوراء وقصر العين وغيرها من القصور)الشرقي، (. وكذلك ظهر في الحيرة عناصر االعمدة 769،ص6004ئري المقطع ام مربع)قديفة،فيها سواء كان دا المركبة وهي مجموعة تتكون من عمود رئيس وسطي تحيط به اربعة اعمدة اصغر، حيث انفرد بهذا العنصر كمادة بنائية او المرمر في نحت وتشيد اآلجر واستعمل فيها (،760،ص6004فضاءات مملكة الحيرة)قديفة، وعن استعمال األعمدة الخشبية في عمارة الكعبة، إذ أن هذه األعمدة لم (.908،ص6077العمدة)رزوقي،ا تكن تقوم بوظيفة حمل األسقف فقط بل إنها استعملت لتعليق صور األنبياء (.7744والمالئكة) جواد،ص تعمل المعماريون األعمدة هذا فضاًل عن البناء في اليمن القديمة لبيوت مرتفعة ذات طوابق متعدد و اس العالية ذوات التيجان في رفع السقوف وفي إقامة الردهات الكبيرة وفي )الطارمات( أمام األبنية وفي واجهات وان سبب استعمالهم للحجارة بدل الخشب هو ان في ذلك على الحجارةالمعابد بصورة خاصة معتمدون وكذلك في اليمن أنواع من األحجار الصالحة ر طويل،الحجارة تتحمل ثقل أكثر من الخشب وتكون ذات عم للبناء والنحت كما توفرت فيها المواد المساعدة األخرى التي تدخل في إنشاء العمارات مثل الجبس. وقد وقد ساعدت ساعدت وفرة الرخام والحجارة الصلدة في اليمن في التعويض عن استعمال الخشب في البناء المصدر السابق(. ومن ء في نحت الحجر وصقله وتكييفه بالشكل الذي يريده)جواد،طبيعة اليمن عامل البنا وقد تمكن المعماريون من وضع الرخام أقيمت أعمدة جميلة كسيت تيجانها بالنقوش وبالزخرف األخاذ. الصخور بعضها فوق بعض وضعًا فنيًا في غاية الدقة جعلها تظهر وكأنها قطعة واحدة. فقد صقلوا الصخور صقاًل تامًا بدقة وعناية، وجعلوا نهايتها متطابقة تمامًا. فإذا جلست بعضها فوق بعض، انطبقت على بعضها، وبدت وكأنها قطعة واحدة يصعب التمييز بين مواضع انطباقها. وقد نقروا أحيانًا في أواسط الرخام نقرًا عميقة، ثبتوا في داخلها أوتادًا من الرصاص أو ن قطع الرخام، ولتكون لها سندًا وقوة، فال تسقط. وقد وجدت مثل هذه األوتاد بين الصخور الحديد، لتربط بي 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 11 وفي العصور اإلسالمية األولى استخدم العمود للمرة األولى ."المكونة لسد مأرب، وكذلك في قصر "غمدان لنخيل حيث أن مسجد في مسجد الرسول )صلى اهلل عليه واله وسلم( في المدينة المنورة. كانت مادته جذوع ا فقد حدد (. يعد أول حدث معماري إسالميًا،7م كما في الشكل) 466الرسول في المدينة الذي أقيم عام والحرم ذو األعمدة الذي المخطط األولي لمسجد المستقبل بأجزائه األساسية،) وهي الصحن الواسع جدًا، .(756،ص7891)بهنسي،(يحاذي الصحن ويكون امتدادًا له من جهة القبلة وبعد هذا المثال كثر استعمال األعمدة في المباني الدينية والمدنية اإلسالمية وعى اختالف أنواعها وأشكالها ودرجاتها، وقد حصل تطور في شكل العمود ومادته وصناعته تبعًا لسنة التطور ومراعاة الظروف محررة على األعمدة القديمة التي نقلوها من الجديدة حيث اعتمد المسلمون على تشييد مساجدهم في األقاليم ال المباني القديمة وظلوا يستخدموها فترة من الزمن حتى بدأ العمود اإلسالمي بالظهور مكتسبا شكال متميزا وكان أول هذه األمثلة األشكال االسطوانية ذات التيجان الناقوسية. ومع تطور الزمن تطورت أساليب البناء وفنونه اإلنشائية فاستخدم الطين والبن واألجر و الجص والحجر والرخام الخشب والحديد إلقامة وتنوعت المواد وتطور العمود عبر العصور التاريخية األعمدة بهيئتها المنفردة والمندمجة بتيجان او بدونها. ويشار إلى نشأة استخدامها والمادة إلى تعدد أشكال األعمدة وتيجانها وقواعدها فهي ال تختلف في وظيفتها و أماكن من أنماط المصنوعة منها منذ أقدم العصور التاريخية والى يومنا هذا. وكان العمود العربي اإلسالمي قد ظهر معروفة وأخرى تأثرت بها فكان لها وجود ارتبط بالمكان، كان أبرزها نمط العمود البغدادي )الدلك( كما في التي يهتم بها البحث في المشكلة البحثية(. وتتمثل 9كل )( ونمط العمود األندلسي كما في الش6الشكل) ، هدف القصور والغموض في تحديد االبعاد و مضامين التي رافقت وجود العمود في العمارة العربية اإلسالمية الكشف عن اإلبعاد والمضامين المختلفة التي رافقت نشأة العمود في العمارة العربية اإلسالمية، البحث البعد التاريخي حث إلى تأشير مضامين مختلفة رافقت العمود والتي تجاوزت البعد اإلنشائي إلى:وتوصل الب األبعاد الروحية والدينية والتعليمية كذلك مضامين أخرى في و .والجمالي والبيئي والحضري والتراثي ي العمارة العربية اإلسالمية . والتي تعد مستويات مقبولة في فهم وجود العمود فوالفلسفية والرمزية والميقاتية ابتدأ من البعد اإلنشائي ووصواًل إلى البعد الديني فيه. ومن خالل هذه الفقرات سيتم طرح مضمون كل بعد. : (literature review) اإلطار ألمفاهيمي-1 سة يوصف "العمود" باللغة العربية برافع هامة الدار والخيمة والمسجد والكنيالعمود لغًة واصطالحًا: 1-1 والمعبد والهيكل وأصبح عنصرا أساسيا من عناصر العمارة. وقد ورد ذكر العمود في القران الكريم في عدة َتاِد 1(و}ِإَرَم َذاِت ال9ِعَماِد{)الفجر89مواضع حيث قال تعالى} ِفي َعَمٍد مَُّمدََّدٍة{)الهمزه َو9 َن ِذي األ9 (}َوِفر9َعو9 َتادًا {70{)الفجر (.1)النبأ(و}َوال9ِجَباَل َأو9 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 بينما يتحقق ظهور العمود في العمارة كأحد العناصر الرأسية لذروة البناء كما)العمود الفقري ( الشامخ برأس ( ة" قديمااة فااي لغااات الشاارق القااديم ،حيااث تاارد فااي اللغااة األكديااة )العراقيااة العتيقااعمووودالمخلوقااات. فااان كلمااة " دها فااااي اآلراميااااة فااااي الشااااام والعااااراق بصاااايغة ونجاااا ( ومنهااااا أشااااتقت )عماااادو(، emeduبصاااايغة )عمياااادو ))الاايمن( بصاايغة )ِعمااد( وفااي اللغااة االنكليزيااة ( وفااي الفينيقيااة )عمااد( والعربااي الجنااوبيemmuda)عمااوادا column) ،كالعنصااار البناااائي فاااي العربياااة العموووود اصوووطالحاً فاااي حاااين ورد أسااام . (576،ص6005)ثاااويني ، وعها )عمد( الواردة في الاذكر الحكايم فاي ساورة الهمازة )ِفاي َعَماٍد ومجم column)بصيغ متعددة منها )العمود (. ثم نجدة بصيغة )سارية 689ُمَمدََّدٍة(، ويرد )أعمدة( أو حتى )عمدان( ما يدعم به سقف او جدار)غالب،ص وسااواري( وهااي أكثاار اسااتعمال فااي المغاارب العربااي وعمااود فااي المشاارق وقااد تكااون قطعااة واحاادة او أكثاار، ماان )وتاد وأوتااد( وكاذلك تارد االساطوانة (، وكذلك679، ص7899او آجر او مواد أخرى متماسكة )غالب،حجارة وهي السارية من األلفااظ النصارانية التاي وقاف عليهاا الجااهليون. وقاد اتخاذها العارب بمعناى العماود الاذي كاان وان " في شعر نسبوه الى "ذي وقد أشير الى "اسط (stylites)يتعبد فوقه بعض الرهبان المعروفين بالعموديين الجدن " وفسرت لفظة "االسطوان" و"االسطوانة" بانها موضع الراهب المرتفع. ويرد بصيغة )سطن( ومجموعها )أساطين(، تسامى األعمادة باألسااطين، وُيقصاد بهاا القاوائم التاي يرتكاز عليهاا الساقف، أو تارد بمعناى )دعاماة( اصار المعمارياة المهماة التاي اساتعملت فاي العماارة العربياة اإلساالمية ومجموعها دعائم والدعاماة وهاي مان العن او اساطوانا و اساطوانة علاى لساان بعاض الكتااب و)شامعة( فاي لبناان. لحمل السقوف والزينة وتقوياة الجادران. أو ( rukn فاي الهناد بصايغة )ركان وترد في العماارة اإلساالمية(1)وقد وردت في العمارة العراقية بكافة مراحلها و تعنااي العمااود الطوياال الخااالي ماان الزخرفااة او post)و (pole وثمااة تساامية شاااخص sutun) )سااطون صاارية. وفاي العاراق ياارد أسام العماود بصاايغة عاامود او بصايغة )دلااك(، وكذلك)دنكاه( ومجموعهاا )دلكااات( أو بفناء الدار. ويرد أسام (، وتخص تحديدا البوائك )أعمدة الرواق( التي تحيط 768)دنك( أو التكمة )الحجية،ص وهاو عماود ملتصاق colossal order) . وثماة عماود )مادغم( (pillarالعماود )الماردي( او بصايغة ركيازة وهناااك تسااميات تاارد ماان مساتدير القطاااع ياازين أحيانااا أركااان الادعائم التااي تحماال األسااقف ويكااون ملتصاقا بهااا. (، ويعني المبنى الذي يستقر ساقفه علاى أعمادة hypostyleأو peristyle وحي العمود مثل )بهو األعمدة .(576،ص6005أو الفناء الذي تدور من حوله البوائك المحمولة على أعمدة)ثويني، المبكرة وهي مزدانة بصنوف من المخاريط الفخارية الملونة إضافة الى المخاريط ( استخدمها السومريون في عصورهم 1) المشابهة لها. وفي العصور اإلسالمية وبخاصة في العصر العباسي أصبحت الدعامات صفة مميزة للعمارة العربية اإلسالمية ها مزينة اركانه بأعمدة صغيرة مندمجة وهي ذات أشكال متنوعة منها ذات المقطع المربع والمستطيل والمثمن والمضلع بعض بنيت من مادة الدعامة او من الرخام وأحيانا من الجص وكان ثقل السقف واقع على الدعامة التي تحمل السقف وتحيط بها)الدراجي(. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 (:the column in islamic architecture) ةالعمود في العمارة االسالمي 1-2 فااي الشااام والعااراق فااي اسااتعمل المساالمون فااي بااواكير ممارساااتهم المعماريااة أعمااده المباااني الدارسااة، الكوفة و مصر والمغرب واألندلس حيث تاوفر الكثيار مان العماائر الحجرياة مان الحقاب الساالفة، ولام يكان يهام البنائون كثيرا عدم التجاانس فاي الشاكل او الطاول، بقادر ماا ياوفره العماود و تاجاه مان تجسايد لساقوف مرفوعاة د باان عاااد حاال بدمشااق فمصاارها و جمااع عمااد الرخااام بطاارق مختلفااة . ويااذكر المسااعودي : ان جياارون باان سااع ( واستعمل المسلمون التيجان المنزوعة من 997-6والمرمر إليها، وشيد بنيانها.)مروج الذهب ومعادن الجوهر العمائر العتيقة الدارسة والتي تشكل اليوم جزء من طرز عمارة المساجد األولى كما األموي في دمشق وقرطبة دنا فاااي احاااد مسااااجد دميااااط شااامال مصااار قاااد وظاااف تااااج قاااديم عناااد قاعااادة العماااود.ورث وقاااد وجااا و القياااروان. المسلمون من األعراف القديمة نظام )األكتاف( التي هي حاله بينيه بين العمود والحاائط الحامال للساقف. وقاد د تباعا في كانت شائعة في البابلية ونجد أجمل نماذجها في اإلسالم موجود في مسجد سامراء الكبير الذي قل م( التاي أنشاأت علاى تخومهاا القااهرة الفاطمياة . أن جال 917ه, 651جامع ابن طولون في مدينة القطائع ) ماان مسااجد اباان طولااون حتااى البنايااات المملوكيااة والعثمانيااة كاناات قااد شاايدت ماان البناااءات فااي مصاار ابتااداءً لحجار الكبيارة مان الجيازة لثقلهاا. وفاي شامال أنقاض مدينة الفسطاط الدارسة ولم يتسنى للبنائين نقل ماداميك ا أفريقياااا نجاااد إن مااادنًا عمااارت بالكامااال مااان انقااااض التاااي سااابقتها فاااي الموقاااع او علاااى تخومهاااا كماااا فاااي وليلاااي الرومانيااه قاارب الرباااط و تمقاااد وتيبااازة فااي ماادن وسااط الجزائاار وبعااد ذلااك قلعااة بنااي حماااد اإلسااالمية فااي ماادن يلية ومستغانم في المغرب، وأنقاض قرطاجة الفينيقية في مدن تونس.شرق الجزائر وبطيوة في مدن مل بالرغم من سهولة وسرعة عملية نقل األنقاض من اآلثار القديمة فأن ذلك كان يحتاج الى مهارة في حيث يقول كوستاف لوبون بهذا الصدد في حضارة العرب ) إن أعمدة المعابد القديمة ، اعادة توظيفها بنائيا ها العرب في قرطبة كانت قصيرة و غير صالحة ليقوم عليها سقف عال كسقف الجامع ) جامع التي آخذ قرطبة( فوضعوا بعضها فوق بعض ساترين عدم صالحها بتلك الحنايا الدالة على مهارتهم الفائقة. وفي هذا وثالثة الصدد البد ان نشير الى ما جا في كتاب )تاريخ العرب( حتى يدعم سقف المسجد الف ومئتان وتسعون عموًدا لها مظهر غابة كثيفة االشجار و ان العدد الكلي لالعمدة في مسجد قرطبة بلغ الف اربعمائة 68عمودًا من الرخام و59(. وكذلك بلغ عدد االعمدة في المسجد االقصى على 79،ص6076عمودًا) بدوي، رة التي تعامل بها العرب وهذا يوضح اصالة العما(. 66،ص6076سارية مربعة من الحجارة )عقل، المسلمين مع مفردة العمود وبهذا الكم الهائل من االعمدة الغير مؤلف في العمائر بقية الشعوب. وفي نفس الصدد قد تسنى للترك أن يستعينوا ببقايا العمائر البيزنطية و يعيدوا لها رونقها في مدن في العمارة اإلسالمية ليست مطابقة لما هو موجود في أسيا الصغرى والبلقان. ونالحظ هنا ان القيم الجمالية العمارات األوربية وال سيما الفارق في تتبع طراز بعينه مثل الطراز الرومانسك او القوطي او الباروك األمر الذي ال يجوز معه تطبيق القواعد األوربية على العمارة اإلسالمية بما يخص نقل أجزاء األبنية الدارسة. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 من ان نشير الى بعض المالحظات من خالل طبيعة العمارة في كونها تواصلية: بدالو المعماري المسلم لم يكن منقطعا عن الطبيعة الحضارية في تفاعله مع ما يدور حولهم ولم يستغن -أوال المسلمون عن خبرات الحضارات األقدم و استقدموا معماريين وصناع من تلك األصقاع. أولى اإلبداعات الفنية اإلسالمية لألعمدة في العصر األموي حيث التاج المنقوش بالخط ظهرت -ثانيًا الكوفي و هذا يبين أن المسلمين قد اخذوا باألسباب و الجوهر و اعتبروا أن عنصر التاج هو محض انتقال ية له دون قيود, مسترسل من دائرة او مضلع العمود الى مربع الحائط أو العقد , ويمكن خلق أشكال ال نهائ ولم يحاكوا في تيجان أعمدتهم أشكاال نمطيه أو طرزا بعينها. لم يأت العهد العباسي بأنواع جديدة في طرز األعمدة على الرغم استعماله في العمارة العراقية بكثرة, -ثالثًا مدة رواق جامع ابن و بالرغم من ذلك فقد انتشر استعمال التاج الناقوسي ونجده أمثلته اليوم في تيجان أع طولون. وفي العهد األيوبي بدأ ظهور التاج المقرنص, وانتشر في العهود الالحقة وظهر في العهد المملوكي نقش األعمدة بالرسومات الكتابية في احد أعمدة رواق الجامع األموي و تعددت أشكال األعمدة في العصور مضلع و المثمن و المربع و المستطيل وما اليها ومنها ما اإلسالمية فكان منها االسطواني و الحلزوني و ال كان مكسوًا بالرخام أو بالجص او بالقاشاني او بالمعدن و بالذهب. ظهر في األندلس خالل العهد الموحدي نوع من التيجان طبق كذلك في شمال أفريقيا ونجده في -رابعًا اع القوم هناك باالعتماد على خامات الرخام الفاخر الذي المسجد الكبير في مدينة تلمسان الجزائرية. و إبد صنعت منه تحفة أعمدة قصر الحمراء و ال سيما في الرواق المحيط بباحة السباع. منذ القرن الرابع للهجرة / العاشر الميالدي صارت لألعمدة تيجانها الخاصة التي تميزها عن التيجان طية , و تميزت بزخارفها النباتية و الهندسية, ودخل الخط العربي عليها ليجعل اإلغريقية والرومانية و البيزن لها خصوصية إسالمية بحتة , و قد عمت الكتابات القرآنية أو الشعرية أو األقوال المأثورة كذلك استغلت ن للخط الكوفي التيجان لنقش اسم الحاكم او البناء او الواقف, و لتسجيل زمن إقامة هذه المشيدة أو تلك, وكا النصيب األوفر من بين الخطوط المستعملة لمثل هذه التيجان. بينما أشار ذات المصدر الى أن تطور أشكال والمزخرف بأوراق النبات فضال عن التيجان في عهود إسالمية أخرى قد ظهر منها التاج البصلي و الناقوسي ية مغايرة لمألوف العمارة اإلسالمية األقدم، أخذت التاج المقرنص. بينما ظهرت بتيجان ذات تأثيرات سلجوق الطرز الجديدة والتي بالظهور و التي لم تكن مألوفة من قبل كالتيجان المزخرفة باألشكال الهندسية, المثلثة منها و المعينية ذات السطوح الملساء النافرة والغائرة مع بقاء جذوع األعمدة كما في العهد العثماني ملساء إذ هد ذلك في التكية والمدرسة السليمانية في دمشق.نشا وفي المغرب واألندلس اتسع انتشار نوع مكعب يكتنفه نحت نباتي سطحي كما في أعمدة قصر الحمراء و مباني فاس وتلمسان، وفي العراق فارس والهند استهواهم النوع المقرنص بينما طغت في الهند خالل حقبة وثة من العمارة الهندية , وتغير ذلك خالل حلول الطراز المغولي و ال سيما بعد السالطين بعض األنواع المور إالمية حديثة بتاج مقرنص أعمدة 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 السلطان األكبر و مرحلة ما بعد فتح بور سكري وقد استعمل الحجر في تجسيد التيجان ثم انتقل الى األجر مقصورات ثم استعمل الخشب في العراق و إيران و أسيا الوسطى , و السيما النوع المقرنص الذي نجده في , في العمارة العراقية تتوج القديمةأصفهان المفتوحة, واستمر حتى أواسط القرن العشرين في بيوت بغداد األعمدة )الدلكات( والذي اضمحل كعنصر إنشائي و جمالي بعد حلول العمارة الخرسانية الحديثة وعاد مجددا ية العقد التاسع من القرن العشرين.يستعمل في الواجهات بصوره ملحوظة في الدور السكنية في بدا وجدير بالذكر ان نتحدث عن أهم أنواع األعمدة في العمارة العربية اإلسالمية احدهما ظهر في . المشرق العربي وهو العمود البغدادي ) الدلك( و األخر ظهر في المغرب العربي وهو العمود األندلسي : the baghdadian column (the dalague) العمود البغدادي ) الدلك( 7-9 (، وعلى الرغم من 6لقد شكل العمود البغدادي حضورا متميزًا منذ القدم في بنية العمارة العراقية، شكل) كونها عمارة جدار إال أن هذا الحضور تبلور في وجود العمود اإلنشائي و الزخرفي والجمالي حيث رافقته بعاد والمضامين األخرى التي اهلته ليكون في صدارة المقرصنات كعناصر تجميلية وتزينيه فضاًل عن األ لبغدادية في االبنية السكنية والتراثية والعامة من النمط الذي يحتوي على األعمدة العراقية وتوجد األعمدة ا فناءات داخلية وسطية مكشوفة باتجاه البيئة الخارجية الطبيعية ونادرا ما يوجد في العمارة الداخلية باستثناء نظام العمود تواجده في بيت الصالة يكون العمود البغدادي)الدلك( أو )التكمة( كعنصر انشائي أساسي في ( اي انه trabeated( كالهما من الخشب او ما يسمى )بنظام العتبة االفقية column&beamوالعتبة ) يسند عتبة افقية مستمرة تحمل فوقها الرواق العلوي او سطحًا والعمود البغدادي في بغداد ومعظم اجزاء العراق ( حيث يسند العمود اقواسًا ويرجع ذلك ىلشمال )نينو قلما يسند أقواسًا أو عقودًا باستثناء بعض األمثلة في ا ومن الجدير بالذكر ، (766،ص6007الى امكانية المادة اإلنشائية )الحجر والمرمر( المتوفرة هناك)شهاب، ان العمود البغدادي )الدلك( يتضمن العناصر األساسية المكونة له عالقات تناسبية منتظمة على غرار عمارة الغربية،وذلك بتأثير المنظومة اإلسالمية والتي تتضمن مجموعة من العمود الكالسيكي في ال التكرار...( فضاًل عن تأثير البعد الديني الفكري على األبعاد -التماثل -االنتظام-الوحدانية-المفردات)التوازن مية لم يأخذ بفكرة الشكلية للعمود. وفي هذا الصدد ال بد من اإلشارة الى إن العمود في العمارة العربية اإلسال محاكاة جسم اإلنسان ال من حيث المنظومة التناسبية وال الشكلية في استعمال هيئة اإلنسان كعمود، مثل ما موجود في العمود في العمارة الغربية. يتكون العمود البغدادي من التاج والبدن والقاعدة وغالبا ما يكون العمود بدن كونه مضلع المقطع وينتهي بتاج مربع الشكل ويفصل ما بين البدن البغدادي بال قاعدة وان ما يميز ال والتاج مقرنصات وزخارف وتشير دراسة )عبد الرسول( الى تصنيف األنواع األساسية للتيجان البغدادية الى ثالثة أنواع : تاج عمود مقرنص، تاج عمود مسنن، تاج عمود على هيئة قبعة القبطان وتشير الى وجود والنسبة الغالبة لعرض التاج 7,5ت بين عناصر العمود البغدادي بين عمق التاج الى مقطع العمود تناسبا ( أما تناسبات القاعدة )عرضا وعمقا( الى مقطع العمود فال يمكن 7/6-7/9الى مقطع العمود هي ) 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 14 بين األعمدة اعتمادها لندرة وجود القاعدة في العمود البغدادي ويمثل عناصر المقرنص األكثر حضوراً البغدادية نقطة االلتقاء بين البدن والتاج. أما بالنسبة إلى أنواع العمود البغدادي)الدلك( فقد أشارة دراسة أو كما (2) إحسان فتحي و جون وارن الى النماذج التسعة في البيوت التقليدية في بغداد وكما في الشكل .(769،ص7815ب مضلع نقوش بنقوش جميلة.)الحجية،إشارة الحجية إلى أن تاج األعمدة يكون من الخش : the andalusian columnالعمود األندلسي 7-6 أن العمود األندلسي يتمثل ضمن نظام العمود والقوس، وهو نظام مختلط يجمع بين منظومتي القوس حضوره ( وحيث ان لكل عنصر في المنظومة beam&column( والعتبة والعمود )arch& pierوالركيزة ) ودوره اإلنشائي والتعبيري، حيث يحقق أعلى أداء إنشائي وارق تعبير حسي، مستفيدا من خصائص المنظومتين، وذلك باستخدام أسلوبين، أسلوب اإليهام إي استحضار عناصر ومفاهيم غير موجودة فعليا ه مع الحفاظ على األداء لتحقيق التعبير المطلوب، وأسلوب الحضور الفعلي في العناصر لكن بتهذيبه وترقيع اإلنشائي له. حيث يحضر العمود األندلسي كعنصر إنشائي حامل وناقل لألثقال ضمن منظومة مختلطة محتفظا بنسبة الرشاقة والصغر، وتمت معالجة االرتفاعات المتنوعة من خالل تطوير نظام متقن سمي بالمستقرات (impostsيؤكد بشكل خاص الخطوط العمودية في ال ) منظومة األساسية فضال عن مرونة التغيير في حيث يصل ارتفاعه في الواجهات الخارجية أبعاده ومن هنا نجد إن العمود يحضر بأبعاد تكاد تكون قياسية. سم ( 65-66سم( في الباحات الداخلية ويتراوح قطره مابين )650سم( فيما يصل إلى )500-665إلى ) بمقارنة هذه األبعاد مع أبعاد الواجهات التي يوجد فيها العمود نجد فيها إال انه وبحور تقترب من ارتفاعه، تفاوت يصل إلى حد الضعف وهو ما تمت معالجته بتوظيف المستقرات لتوازن الخطوط العمودية المطلوبة فعليا كعنصر إنشائي تتناسب فيه نسبة االرتفاع مع لتشكيل الواجهة، ومن هنا فان العمود األندلسي يحضر ( ممثال pierالحضور الفعلي األخر هو الركيزة ) .(2)المقطع على نحو يقترب من معامل النحافة القياسي ( فهذه الكتل المستطيلة التي تعلو األعمدة لموازنة الواجهة وفتحاتها تتصل فعليا impostsبالمستقرات) وبذلك فأنها تعادل قوى الدفع االفقي وبصريا وتتجاور مع االقواس التي تعلو البحور الفاصلة مابين األعمدة التي تسلطها االقواس وتحول مسارها الى االسفل نحو األعمدة، ويتم تصنيف انواع األعمدة في العمارة (9االندلسية الى اربعة انواع حسب تيجانها التي تستقر على جذع العمود وكما في الشكل) (والسمك الفعال effective height(: وهي النسبة بين االرتفاع الفعال )slenderness ratioمعامل النحافة ) (2) (effective thickness.وتعد قيمة اساسية في التصاميم االنشائية لألعمدة ، ويتوقف عليها االداء االنشائي له .) 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 45 :the connotations & dimension of columnاالبعاد والمضامين في العمود -2 لقد اهتم البحث بتحديد األبعاد االساسية التي اثيرت حول العمود، بموجب الدراسات والبحوث المهتمة بالعمارة ) 6العربية اإلسالمية. فقد تم تقسيمها الى ثالثة مستويات، شكل) the structural dimension of the:البعد اإلنشائي للعمود -: المستوى األولأوالً column: ( او عنصر قائم ، داعم لسقف او جدار verticalَيعد العمود في العمارة عنصر إنشائي شاقولي) عتبة او عقد ويراد منه نقل احمال العناصر األفقية في التسقيف وما -( او اسكفة68، ص6005)وزيري، قل لألرض وهكذا فهو وسيلة نقل يستند علية وبحسب الحلول المعمارية الى القواعد واألسس التي بدورها تن العزوم لعناصر الهيكل األفقية. والقصد منه االستفادة من المساحات الحرة التي توظف كفضاءات معمارية بسبب اضطالع العمود بمهمة نقل ثقل السقوف، واوجد حاجة اثمرت عن روح االبتكار للبنائين ربما يكون بون بين أعمدة معابدهم خشية عدم تحمل الجسور في البحور سبب كافي بان جعل المصريون القدماء يقار الفاصلة بين األعمدة كما هو الحال في معبد الكرنك وبالنتيجة فقد قضمت ضخامة تلك األعمدة وتقاربها المبالغ فيه فسحة الفضاء المتاح لالستغالل الوظيفي واستعمل في تجسيد هذا العنصر الهيكلي خامات متعددة في البيئات فجاءت من خامات القصب والخشب وجذوع النخيل واآلجر والحجر و أمست في بحسب توفرها األزمنة المتأخرة من الحديد والمعادن او من الخرسانة المسلحة التي شاعت وال تجد لهل منافس يؤلف العمود ثيرة تم توظيفها في احد العناصر األساسية والمهمة في العمارة العراقية استخدمت في تنفيذها مواد أولية ك أماكن مختلفة من المبنى تتناسب وطبيعة المبنى والمواد اإلنشائية المستخدمة في اقامتها ومن أهم وظائف العمود حمل السقف وتعد هذه الوظيفة أهم ما يميز األعمدة ويحدد عملها ووظيفتها ودرجة استخدامها وأماكن البنائية التي يتألف منها المبنى وهذه الوظيفة لم تتغير المنشآتوجودها ومادتها اإلنشائية ومدى انسجامها من منذ أقدم العصور التاريخية وحتى يومنا هذا نراها ممثلة في المساجد والجوامع والبيوت والقصور والخانات والحمامات واألسواق والقيصريات وكانت متزامنة مع تطور العمارة وتوسع حجوم الوحدات البنائية. وفي قصر هجرية نالحظ وجود عدد من 746االخيضر الذي يعود تاريخ إنشاءه الى العصر العباسي األول الى عام الدعامات تتقدمها مجموعة من األعمدة االسطوانية لرفع العقود وكذلك الحال في المسجد فيه وترتكز بعض هذا العصر كثر استعمال األعمدة على قواعد دائرية يتوج البعض منها تيجان والبد من التنويه إن في الدعامات جنبا الى جنب مع العمود الذي بني من اآلجر الحجر وبعضها كان من الجص وأكثر األعمدة للعمود عدة أجزاء وهي التاج شيوعا العمود ذو المقطع األسطواني والمضلع والحلزون. ومن الناحية المعمارية يح عليها كتف العقد، وفي بعض االحيان تستعمل رباطات من تعلو القرمة وتعلو هذه الحدارة )الطبلية( ويستر الخشب او من الحديد تربط بين األعمدة لمقاومة القوى االفقية الناتجة من دفع العقود وكذلك لحمل مصابيح 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 اإلنارة، ويرتكز التاج على البدن وهذا يتكئ على قاعدة دائرية تحملها حليات قد تخرج عن الدائرة اسفل العمود ادة تستغل هذه القاعدة لتسجيل األسماء او التواريخ وقد يظهر الخط على أجزاء أخرى من العمود أيضا وع وينتهي من األسفل بقاعدة مربعة تحمل الدائرية وله أساس تحت مستوى بالط األرض يسمى (.689، ص7899)غالب،وسادة انشائيين يتمثل األول بنظام الجدران ومن هذا يتضح أن العمارة العربية اإلسالمية قد استعملت نظامين الذي استعمل بكثرة في مساجد (skeleton system) والثاني النظام الهيكلي bearing wall))الحاملة الجمعة التي تستلزم فضاءات واسعة الستيعاب أعداد المسلمين المتزيدة، وهذا النظام يتطابق مع الوظيفية من امكانيات كبيرة في تسقيف الفضاءات الواسعة بفضل استعمال األعداد هاإلنشائية للعمود نظرًا لما يوفر قبل اإلسالم. مستعملينالكبيرة من األعمدة. ومن الجدير ذكرة ان هذين النظاميين االنشائيين كانا ويذكر السلطاني فعندما تكون ثمة حاجة تصميمية، لتحديد صارم للفضاء المصمم والرغبة في عزل صامه عن البيئة الخارجية، تتيح منظومة "الجدران الحاملة " بصالدة سطوحها المصمتة، الفضاء، وانف وفتحاتها المقننة وأسلوب بنائها الرصين، قوة تعبيرية مقنعة وواضحة في هذا المجال، في حين يمد"النظام دة وسيطرة الفضاء في الهيكلي" تركيبة القوام اإلنشائي بمزيد من اإلحساس بالخفة والشفافية، ويجعل من سيا .(96، ص6004الفراغات المصممة امرًا واضحًا، يمكن ادركه)السلطاني، مما تقدم فان الوظيفية اإلنشائية للعمود في العمارة العربية اإلسالمية تمثل جانبًا اساسيًا ضمن تي تنجزها على مجموعة اإلبعاد والمضامين األخرى للعمود فضاًل عن ما تقدمه من العالقات التركيبية ال مستوى الفضاءات وهي تتحقق تكنولوجيًا وتقنيًا عبر العصور والطرز المعمارية المرافقة لها وعبر اإلمكانيات اإلبداعية التصميمية في عكس خصوصية الجوانب التعبيرية والداللية. :المستوى الثاني –ثانيًا :the historical dimension of the column البعد التاريخي للعمود أ تعددت أشكال األعمدة بتعدد الطرز والعهود التاريخية ، واختلفت طرزه باختالف األقطار ثم الثقافات الخاصة بكل اإلبداعاتوالديانات والمعتقدات، فضاًل عن كونها بقيت تحاكي األشكال الطبيعية حيث تعززها للطراز في كل مدرسة معمارية. ونرصد هنا أقدم عصر او مرحلة، والسيما العناصر الزخرفية والتيجان المميزة استعمال لألعمدة يرد في العمارتين العراقية ثم المصرية، وقد كان للعمود السومري المتكون من حزمة القصب تأثير الحق حتى على العمارة اليونانية، حيث يورد بعض منظري العمارة بأن السواقي الطوالنية أو الحنيات ، وكذلك حلية الخلخال الناتئ المطوق للعمود أفقيا، ما هي إال إبداعات جمالية flutedالمقناة في الجذع وردت من محاكاة لألصل القصبي للعمود، حينما تظهر تلك السواقي على ظاهر العمود المتكون من حزم وكيف . مودالقصب، والتي تشد بعقال قصبي كي ال تنفلت و الذي شكل اإليحاء األول لهيئة الخلخال في الع 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 األمر ذات وظيفة إنشائية ومن ثم تحولت الحقًا الى عنصر تزييني. ثم ورد من العمارة بادئكانت في السومرية واألكدية محاكاة لتك األعمدة ولكن مصنوعة من خامة الطوب أو اآلجر، بهيئات مربعة أو دائرية، مثلة في القاعة العراقية في متحف اللوفر تصنع خصيصا لما يخدم عملية التناسج بين قطعها، ونجد خير األ المتكون من أربعة أعمدة ضخمة آجرية، حيث يتشكل العمود من أربعة أسطوانات دائرية متماسة تحصر بينها نجمة مربعة. وفي هذا السياق نعتقد أن تلك األشكال األولى لألعمدة قد أنتقلت الى عمارة العالم، ونجد لها أخرى، بقيت لردح من الزمان تشكل النماذج الريادية، ونجد إقتباساتها في األعمدة أحيانا محاكاة في طرز المحيطة بأحواش)أتريوم( بيوت مدينة بومبي الرومانية التي دفنتها حمم البركان في القرن الثالث قبل الميالد .رة العراقيةكانت معمولة من آجر مشكل بطريقة مدورة، وهي محاكاة لألعمدة التي استعملت في العما من الجدير بالذكر أن أعمدة القصب التي وردت لدى العراقيين القدماء ورثها سكان األهوار في ( حيث أن بيوت القصب )اكواخهم 99،ص6004الجنوب العراقي اليوم وهي تمثل عمارة القصب)العتابي، ى لديهم )شبه(، تكور وتربط في اوصرائفهم( تبنى بمنظومة أعمدة مكونه من حزم قصبية معصوبة، و يسم نهايتها العلوية ثم تشد بعناصر أفقية من حزم القصب تسمى )اهطار( لكي تمنع حركتها األفقية ثم تغطى (. 99،ص7815بطبقات من الحصران )البواري( المشغولة من ظفر عيدان القصب المشظى )الجويبراوي، ليدية في عمارة القصب . لذلك فليس من المستغرب ان وهذه الطريقة إبداعي إنشائي مبكر عن األعمدة التق نجد أقدم األمثلة عن فن العمارة في عصر ما قبل الكتابة في األختام االسطوانية والرسوم النافرة حيث كانت األبنية مكونة من القصب وتشبه في تفاصيلها )المضيف( الذي نشاهده في قرى مناطق المستنقعات في هذه بيت الضيافة "ليدي درور" أن استعمال القوس ( فضاًل عن ذلك تذكر العالمة البريطانية51،ص7889أليام)سيتون لويد،ا في عمارة القصب هو األساس الذي اعتمد عليه في التشييد اإلنشائي فيما بعد في العمارة الحديثة. وتذكر ة إلى أهوار العراق تقول: تبنى "ليدي درور" في محاضرة لها في الجمعية الملكية اآلسيوية الموسومة: رحل منازل سكان األهوار من القصب بالكامل دون استعمال مسمار أو برغي. وصريفة القصب تشبه الخيمة، والغطاء هو بواري توضع فوق هيكل من حزم مربوطة بعناية. وتسمى هذه الحزم" ِشباب" )مفردها ِشبه(. كوا األكبر حجمًا، مثل مضايف الشيو ، فهي بناء وتربط حزم القصب القوي بحبال من البردي. أما األ عظيم بحق، فالمضيف الجيد يكون أحيانًا بحجم كنيسة صغيرة. وتغرس حزم القصب في األرض عند البناء بصفين، ثم تحنى لتلتقي أزواجًا عند القمة وتربط بعناية فائقة بحيث يستحيل رؤية موقع االتصال بين ويعتقد الكثير هذه هي أسالف القوس المعماري) ليدي ،سم( 40ألضالع قدمين )الحزمتين. ويبلغ سمك هذه ا .(9،ص6006درور، وقد أستوحت عمارة الهياكل الحديدية الحديثة هذا النوع من الحلول خالل مبنى )رواق المكائن galarie de machine س ، حينما جعلت األعمدة الحديدية بشكل نصف قو 7999(المقام في باريس عام 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 العمارة واعتمدت .متر100( وأمست بحورها حوالي articulate -وربطت نهاياتها السائبة بشكل )مفصل عنصر العمود المبني من الحجر، ويمكن أن يكون قد سبقتها خامات نباتية استعمالالمصرية القديمة على أشكال منحوته تحاكي جريد بقيت أشكالها في النحوتات التي أختصت بها التيجان أو أطناف المباني، مثل النخيل أو زهرة اللوتس أو زينة )خكر( التي هي عبارة عن رؤوس جذوع البردي التي كانت تربطها عصابات من أعالها وأسفلها. وكانت توضع األعمدة في صفوف داخل البيوت الكبيرة والمتوسطة، وقد وردت في بعض لتي مزج المصريون فيها بين تمثيل المسقط والمقطع أو الرسوم التمثيلية، كما في رسوم تل العمارنه، ا الواجهة، التي تظهر شكل األعمدة .(471،ص6006ومواضعها)ثويني، ووردت األعمدة عند نبط )البتراء( او عند قوم )صالح( و)عاد( منحوتة في الصخر، وينحت الفرس لواردة من العمارة اآلشورية كما في آثار األخمينيون تيجان أعمدتهم على شكل ثورين، متأثرين بحظوة الثور ا برسيبوليس،.. وعلى العموم فأن طرز األعمدة اليونانية جاءت على ثالث أنواع ال يتسع المجال هنا لذكرها ان طبيعة الحياة والظروف التي أحاطت بعصر النبي محمد)ص( وعصر الخلفاء الراشدين لم تهيئ للمجتمع خصبًا لفن يترعرع بينهم ويتطبع بطابعهم، كما حرص نبي المسلمين نفسه اإلسالمي حينئذ أن يكون مرتعاً على تجنب كل مظهر للبذ والترف. فاتبع النبي محمد)ص( وخلفائه األربعة الراشدون البساطة في العيش، ط للعبادة تفي فق مساكنهم بسيطة استخدمت فيها الخامات البدائية، كما اكتفوا بتشييد أماكن بسيطة وكانت كان عبارة عن مساحة مربعة حاجة إقامة الشعائر الدينية، فمسجد المدينة كان ملحقا بدار الرسول الطين والحجر، ويغطي جزء من سقفه بسعف النخيل المغطى (. يحيط بها جدران من79ص،7889)عالم، هو جمع السقف عدد من جذوع النخيل. وكان الغرض األول من إقامته بطبقة من الطين، ويرتكز هذا العرب متسع ليقفوا صفوفا في مواجهة الكعبة في مكة. أما في العراق ومصر فقام المصلين في مكان واحد هجرية 71هجرية والكوفة عام 76بتأسيس مدن جديدة شيدوا فيها مساجد بسيطة، ففي جامع البصرة عام والجريد، فوا جزءا منه بالخشبالمسلمون بإحاطة قطعة األرض بخندق محفور بداًل من الجدران وسق اكتفى من الكنائس، أو من وكان يحمل السقف أعمدة من جذوع النخيل أو من األعمدة الحجرية التي جلبوها القصور التي وجدوها في إقليم الحيرة على حدود العراق، وجاء إن القائد سعد بن أبي وقاص أمر أن يسقف هذا التصميم (. ولقد تكرر74،ص 7895جميلة)نخبة، بيت الصالة فيه وحملت ذلك السقف أعمدة رخامية عمل على توسيع ا. وفي بداية العصر األمويااه67البسيط في جامع عمرو الذي شيد في مدينة الفسطاط عام ، وما عادت المساجد األولى قادرة على ازداد عدد المسلمين زيادة كبيرة المساجد التي كانت قائمة، إذ زيادة كبيرة ، وتم بناءه باآلجر والجص ورفع ( ها55عام زاد في المسجد " لبصرةاستيعابهم ، حيث في ا (، و بالساج عمل سقفه، و أتى8،ص7895سقفه على أعمدة حجرية ثم جعل له مقصورة و مأذنة )نخبة، وبناه باللبن و الجص واتقن " بأعمدته من جبل األحواز كما وساع جامع" الكوفة 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 41 فر ل لرفع سقوفه األعمدة الرخامية الرشيقة وتيجانها ذات الزخاتخطيطه وبناءه واستعم ."مسجد الكوفة" و"مسجد البصرة" ( في كل من74،ص 7895المتقنة) نخبة، اشتهرت العمارة العربية اإلسالمية في العصر األموي باستخدام العقود المحمولة على أعمدة رخامية ي المشيدة في العصر الروماني , أما بالنسبة للعقود اقتضت الضرورة أحيانًا ألخذ بعضها من المبان المستخدمة فكان منها ابتكار عربي إسالمي ومنها كان سائدًا في العصور السابقة وأغلب العقود المستخدمة عقود نصف الدائرية وحدوة الفرس والمدبب والمستقيم واستخدموا األوتار الخشبية في ربط األعمدة بعضها تأثر العمارة األموية بالعمارة السورية, بل نهلت من العمارة في بالد الرافدين. المسجد بعض, ولم يقتصر ذراع وتم استعمال 600 الجامع في واسط شيده الوالي الحجاج بن يوسف الثقافي بشكل مربع اضالعه عت مكشوفة ورف بباحةاآلجر والجص وفرشت أرضه بالطابوق ويتألف من مصلى ومجنبتين ومؤخرة تحيط سقوفه على أعمدة اسطوانية فخمة من الحجر رملي مزينة بنقوش هندسية ونباتية متداخلة مقتضبة وجميلة ويتألف العمود آنذاكوتعبر عن ذوق العرب المسلمين والمستوى الفني الذي كان عليه النحت على الحجر هكذا يمكن القول أن فن و (.56،ص7895مركزها)نخبة، الواحد من عدة قطع اسطوانية ويربطها سفود في العمارة العربية اإلسالمية ولد ونما وترعرع سريعًا وبدأ بامتالك خصوصيته ووحدته وأنماطه اإلسالمية فكان التي ما ركيزة رائعة لمدارس رائعة في فن العمارة العربية اإلسالمية. حيث بدأ إنشاء المباني الضخمة والمتميزة اإلسالمية المبكرة. نيانها تشهد على عظمة الحضارة العربيةزالت قائمة حتى اآلن محتفظة بب :the aesthetic dimension of the column البعد الجمالي للعمود ب نه يؤخذ من كل معاني الخير والتخلق والتجمل أن مفهوم الجمال مبثوث في أصول الدين وفروعه، وا ة في القرآن الكريم والسنة النبوية. وذلك يعني إن اهلل والتزين و اإلحسان ونحو هذا من معاني الجمال المبثوث الذي جعل الدين جمياًل، قَصد أن يكون جمياًل قصداً وتشريعًا أصياًل. بمعنى أن ذلك ُقِصَد فيه ابتدءًا وليس دة اإللهية التي قضت أن يتجمل الناس بالدين ويتزينوا به عبا اإلرادةمصادفة أو اتفاقًا، فالجمال متعلق بتلك هلل رب العالمين، ومنهاجًا لعمران اإلنسان في األرض، مصدقًا للحديث النبوي الشريف:" إن اهلل تعالى جميل والتجمل المطلوب، مبنى ومعنى، رسمًا ووجدانًا في هذا الحديث يتعلق بالشكل والمضمون يحب الجمال". ي كما هو في ديدن اإلبداع البشري وأضفى وفي ما يخص العمود فانه تعدى الهيئة البنيوية إلى البعد الجمال عليه معالجات وتزويق وضبط للنسب الجمالي أو حتى معالجة بعض الخدع البصرية كما هو الحال لدى اليونان حينما أضفوا انتفاخًا في وسط العمود كي يبدو للناظر سويًا عداًل وليس منبعجًا من وسطه لو كان قد جدير ذكره ان هذا المبدأ في معالجة الخدع البصرية البنائية وقد ورد ومن ال ترك على سجيته الحجمية، اليونان من مصدر العمارة العراقية القديمة حيث ورد أول وأقدم مثل باق اليوم على ذلك في المعبد األبيض قبل في تل خفاجي الواقع حاليًا ضمن محافظة ديالى شمالي شرق بغداد والذي يعود الى نهاية اإللف الثالثة الميالد في حضارة اشنونا. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 يعد من عناصره التكوينية الجمالية وهو رأس العمود أو الجزء الذي يتوج capital )ان تاج العمود) أعاله وهو يشكل الحالة االنتقالية من العمود إلى الطاق او الجسر الذي يعلوه والتاج اما بسيط او مزخرف كل مدرسة معمارية وبالرغم من ذلك فلم تنتقل تلك الطرز بحذافيرها وتختلف زخارفه باختالف الطابع الفني ل او حتى انقرضت في فنون االقليم فمثاًل قام العراقيون القدماء في تحويل األشكال االبتكارية ألشجار النخيل ( وأن تيجان األعمدة الفرعونية التي 708،ص6076و زهرة اللوتس لتصبح تيجانًا لألعمدة )جودي، بتأثيرات نباتات البردي وأزهار وادي النيل ولم تنتقل تلك الطرز إلى تيجان األعمدة في مصر اضطلعت اإلسالمية والحال نفسه لدى الفرس االخمينيون الذين نحتوا تيجان أعمدتهم على شبه ثورين، ولم تعمم في ة اإلغريقية والتي في حقيقتها التيجان اإلسالمية و أكثر التيجان انتشارا هي التي يقال بأنها نشأت مع العمار ( وعلى prelonicجاءت من مصادر حضارة بالد الشام والسيما الفينيقي منه بما دعا )السابق لأليوني العموم يمكن رصد تلك التيجان المتميزة. سريع على مجمل وهذا يؤكد األثر الكبير للجانب الديني الروحي التوحيدي للقيم اإلسالمية بشكلٍ لعربية اإلسالمية، وظهرت أولى اإلبداعات الفنية اإلسالمية لتيجان األعمدة في العصر األموي العمارة ا حيث نجد التاج المنقوش بالخط الكوفي هذا يبين أن المسلمين قد اخذوا باألسباب والجوهر واعتبروا أن أو العقد ويمكن خلق عنصر التاج هو محض انتقال مسترسل من دائرة أو مضلع العمود إلى المربع الحائط األشكال متعددة دون قيود ولم يحاكوا في تيجان أعمدتهم أشكااًل نمطية أو طرزا بعينها. وفي العصر العباسي وصلت األعمدة ذروتها عددا وتنظيما في بعض المباني العباسية ففي سامراء وفي الجامع الكبير ) جامع وجود األعمدة ال يقتصر على النوع المنفرد منها بل عمودا ويالحظ أن 699الملوية ( حيث يحتوي على ، ص 7896يتعداه إلى المزدوج والثالثي والمندمج مع الجدران كما في عمارة األربعين في التكري )شريف، ورغم أن العصر العباسي لم يأت بأنواع جديدة في طرز األعمدة لقلة استعمالها في العمارة العراقية (.688 عمات أكثر من العمود بالرغم من استقرار العصر العباسي حضاريًا ومعماريًا و أنعكس في و اعتماده الدا ثبات التصاميم المعمارية لجميع الوظائف والفعاليات المعمارية اإلسالمية في أنماط معمارية مختلفة مثال ط المشافي ونمط ذلك نمط المساجد ونمط الزوايا والرباط ونمط األسواق والقيصريات ونمط الخانات ونم المدارس ونمط الحمامات وغيرها من األنماط المعمارية والتي انتقلت فيما بعد إلى بقية العالم اإلسالمي. إال إن ذلك لم يمنع من انتشار استعمال التاج الناقوسي ونجد أمثلته في تيجان أعمدة رواق جامع ابن طولون انتشر في العهود الالحقة و في العهد المملوكي ظهر نقش في العهد األيوبي، بدا ظهور التاج المقرنص و األعمدة بالرسومات الكتابية في أمكنة محدودة كأحد أعمدة رواق الجامع األموي وعمود أخر إلى يسار الخارج من بابه الشمالي بينه وبين ضريح صالح الدين األيوبي. وبغية تحقيق البعد الجمالي فقد تعددت لعصور اإلسالمية فكان منها االسطواني والحلزوني المضلع والمثمن والمربع والمستطيل أشكال األعمدة في ا ومنها ما كان مكسو بالرخام أو الجص او بالقشاني او بالمعدن وبالذهب وظهر في األندلس خالل العهد 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 ن الجزائرية ألموحدي نوع من التيجان طبق كذلك في شمال أفريقيا ونجده في المسجد الكبير في مدينة تلمسا وأبدعوا هناك على خامات الرخام الفاخر الذي صنعت منه تحفة أعمدة قصر الحمراء والسيما في الرواق المحيط بباحة السباع. ان األعمدة التي ابتدعها فنانو العمارة اإلسالمية كانت تتميز بأشكال حلياتها الشرقية وتمتاز بالبساطة ة للقطر ومن ميزاتها ان لها تيجان متناسقة وذات رقبة طويلة وصفحة مر 76وعادة ما تكون نسبة ارتفاعها مربعة مشغولة بالمقرنصات مع أشغال األرابيسك التي تركز فوقها العقود و زينت األعمدة بتيجان ذات مقرنصات وبطحات مختلفة األعداد وكذلك الداليات التي تشبه خاليا النحل أو بهيئة أشرطة بارزة وغائرة تزينيه زخارف نباتية والبعض األخر مجرد من الزخرفة أو تقعرات وتحدبات متتالية ومتدرجة تبدأ من بعضها األعلى حيث صفحة تاج العمود وتنتهي أسفل التاج فتكون بمستوى بدن العمود هذا فضال عن وجود أشكال تدرج المحزز والمشطوف أخرى اتخذت اشكااًل عدة منها الدائري والمربع الحلزوني والمثمن والمضلع الم األركان والمزين بأشكال نباتية وهندسية وأحيانا حيوانية وآدمية وطيور بوضعيات مختلفة تتناسب وشكل (. على مر التاريخ كانت وظيفة األعمدة انشائيًا في حمل السقوف إال 4، ص6001العمود ومادته )الدراجي، ن وتجميل المداخل في المباني الدينية والمدنية من معابد أنها استعملت لتحقيق الوظيفة الجمالية وذلك لتزي مساجد مدارس والخانات والحمامات و أسوار المدن وبواباتها من الخارج أو استعمالها في العمارة الداخلية في ذلك الغرض الجمالي حيث نجدها في صحون المساجد أو القصور والبيوت أو في الحرم نجدها تأخذ البعد ي جانبي المحراب وتزين الجدران فيه. الجمالي ف the environmental & urban dimension of theالبعود البيئوي والحضوري للعموود ج column: أن حضور العمود على المستوى البيئي والحضري هو حضور متاداخل باين هاذين البعادين او العااملين احات العامة والرئيسة وعلى الرغم من تواجاده حيث تمثل في وجود األروقة المعمدة على جانبي الشارع او الس فااي حاااالت نااادرة ) علااى عكااس مااا موجااود فااي الاادول األوربيااة( فمااثال فااي العااراق يكاااد يقتصاار حضااوره علااى المدن الرئيسة في بغداد والنجف األشراف والمحافظات األخرى، كمثال شارع الرشيد وبعض شاوارع الكاظمياة لسااحات مثال سااحة االحتفااالت وسااحة الغرياري فاي شاارع الرشايد المعاصارة و حديثًا في شارع حيفا وبعاض ا بعااض الشاايء, حيااث تعماال األعماادة علااى الحمايااة ماان الظااروف المناخيااة القاسااية سااواء فااي الصاايف أو فااي الشتاء حيث تشكل األعمدة خيارًا مناخيًا يخفف من وطاأة الماؤثرات المناخياة فضاال عان شادة اإلناارة الطبيعياة دة الساااطوع المؤذياااة للعياااون. وكاااذلك توجاااد األعمااادة فاااي األبنياااة التراثياااة مااان الااانمط الاااذي يحتاااوي علاااى الشااادي الفناااءات الداخليااة وسااطية مكشااوفة باتجاااه البيئااة الخارجيااة ممااا تشااكل األعماادة اطااارًا خارجيااًا محااددًا لحافااات تااوح علااى الفناااء( بااين الجاازء الفناااء عاان الجاازء المسااقف )طارمااات( حيااث تشااكل فضاااءات انتقاليااة ) مسااقف مف المكشوف واألخر المغلق. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 :the heritage dimension of the column البعد التراثي للعمود د ان مجمااال األبعااااد والمضاااامين األنفاااة للعماااود التاااي تااام التطااارق إليهاااا و فضااااًل عااان األخااارى التاااي سااايتم كبيار مفهاوم الخصوصاية و الُهوياة الحضاارية التطرق لها الحقًا تشكل البعد التراثي حيث يؤكد التراث إلاى حاد والثقافية لدى كل أمة ، وهو بهذه الصفة يحمل الشارعية اإلنساانية والفكرياة والحساية وآفااق اإلباداع الثقاافي فاي أرثاً مرئيًا ومعاشًا يحيط بكل جوانب حياتنا وذاكرتناا وارواحناا وبالنسابة للتاراث فهاو مفهاوم لتلاك هالمجتمع. كون ة اإلنسانية المعنوية او الروحانية المتضامنة والمتفاعلاة ماع الوظيفاة. فاي حاوزة هاذا اإلطاار الفكاري الخصوصي فان التراث في ماهيته ومفهومه يعد وظيفيا وحتمياا للوجاود اإلنسااني ويتواجاد وظيفياًا وجمالياا بانفس الوقات فاي (. 59،ص7896صنع العمل الفني")محمد مكية، :the social dimension of the column البعد االجتماعي للعمود ه يعد حضور مفردة العمود في الذاكرة الجمعية للمجتمع وفي البنية المعمارياة علاى المساتوى العمراناي أو ضمن النسيج الحضري بعدًا اجتماعيًا، على اعتبار إن العمارة تشكل جزءًا أساسًا في كينونة المجتمع وتشاكل ه(، حيث ال يجوز النظر للعماود بمعازل عان الفعال او فضااء54ص،6004ابي،المؤشر لثقافة مجتمع ما)العت وسااحات الشاوارع وفاي عماارة مسااجد االجتماعي سواء على مستوى المدينة حيث نجده فاي البياوت والفنااءات ألصااالحين أو فااي النساايج الحضااري فااي األولياااءأهلل وفااي مراقااد األئمااة األطهااار)عليهم السااالم( أو فااي تاارب ة األروقااة فااي شااوارع المدينااة او فااي فناااء الاادور او يتقاادم مااداخل األبنيااة العامااة والاادور السااكنية او فااي أعمااد الخيام في عمق الصحراء وفي بيوت القصب او في مضايف العشاائر العربياة يتقادم او يادعم او يساند أجازاءه اصار معمارياة غارقاة فاي عماق في الداخل والخارج بأشكال تدل على عمق ارتباطه الحضاري الذي يرتبط بعن الحضاااارات، الاااذي يبعاااث فاااي الااانفس األماااان واالطمئناااان ويزياااد مااان التاااآلف و الحميمياااة والتاااي تااادعم التكافااال االجتماعية. وفضاءه االجتماعي يشكل سياقا زمكانيًا فالسياق المكاني مرتبط بعالم الحياة ويحمل معنى للفرد حياااث باادون هاااذا التاارابط يحااادث التفكااك فاااي النسااايج والتااااريخيماااعي اذ انااه مااارتبط بااالموروث الثقاااافي واالجت المكااااني واالجتمااااعي الاااذي يااارتبط بالااادالالت القيمياااة التاااي تضااامن اإلطاااار العاااام للخصوصاااية المكانياااة أماااا السياق الزماني فانه مقوم واصح ذا داللة يؤكد في كل لحظة من لحظات الزمن على حالة الترابط التي يعيش فيها وبذلك تتشكل الهوية العامة للمجتمع. المتلقي ومما تقدم يمكن ان نقول: أن العمود لم يكن عنصر معماريًا طارئًا على العمارة العربية اإلسالمية بل عنصرًا معماريًا أصياًل في نبثق من نبع الحضارات المتالحقة الذي ا التاريخيبنية العمارة العربية اإلسالمية استقى عمقه الحضاري و من وسطها وانعكس في تلك األشكال األولى لألعمدة وفي طرز معمارية الحقة، والتي بقيت لردح من الزمان 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 تشكل النماذج الريادية للعمود العربي اإلسالمي وعلى سعة المساحات التي مثلها عقائديًا ومعماريًا وحضاريًا. التي حققت هويته المعمارية. وأنماطه وحدتهوهذا يؤشر خصب االنتماء وامتالك خصوصيته و سريع على مجمل أن األثر الكبير للجانب الديني الروحي التوحيدي للقيم اإلسالمية الذي انعكس بشكلٍ العمارة العربية اإلسالمية، تعدى الهيئة البنيوية للعمود إلى البعد الجمالي كما هو في ديدن اإلبداع البشري للنسب الجمالية او حتى معالجة بعض الخدع البصرية وهذا يؤكد إن وأضفى عليه معالجات وتزويق وضبط البعد والمضمون الجمالي كان يتقدم على بقية المضامين في العمود العربي اإلسالمي حيث تشكل الجوانب التعبيرية والداللية مقومًا لها. بعدين حيث يعمل ان حضور العمود على المستوى البيئي والحضري هو حضور متداخل بين هذين ال عن البيئي على الحماية من الظروف المناخية القاسية حيث يشكل فضاءًا بينيًا بين الداخل والخارج فضالً كونه يشكل معالجات للفضاء الخارجي. ومن ذلك نخلص إلى أن التراث هو ما بقي من نتاج األسالف وفعلهم في الحياة فكريًا وماديًا، وأن صبًا وأصياًل في تنمية القدرات اإلبداعية كونه األكثر غوصًا في أعماق التاريخ. أن التراث ُيعد مجااًل خ الدالالت والمعاني الروحية والرمزية والتقليدية واستيعابتناول التراث في عمقه وفنونه الجمالية والقيمية صرة وفتح المجاالت فيه يعتبر الجسر الناقل لإلشارات والرموز والموصل والمؤهل لتقبل المفاهيم المعا واألفاق أمامها لالستفادة منه بغناه المادي والمعنوي. ان البعد االجتماعي يمثل جزءًا اساسًا في كينونة المجتمع حيث يعد حضور مفردة العمود في الذاكرة الجمعية للمجتمع وفي البنية المعمارية على المستوى العمراني أو ضمن النسيج الحضري يعد بعدا االجتماعي يشكل سياقا زمكانيًا ينسج خيوط خصوصيته وهويته االجتماعية هيًا، وفضاءاجتماع والمعمارية. المستوى الثالث: -ثالثًا :the spiritual & religious dimension of the columnالبعد الديني الروحي للعمود أ واألساطين ويقصد بها القاوائم كان الصحابة )رض( والسلف من بعدهم يتحرون الصالة عند تلك األعمدة وبمااا أن ماان جلااوس النبااي )ص( ونومااه وتهجااده باال وحياتااه. ال تخلااواالتااي يرتكااز علهااا السااقف التااي كاناات جلوسااه )ص( كااان عنااد هااذه األعماادة فإنهااا كاناات محااال لناازول الكثياار ماان اآليااات القرآنيااة, وورود األحاديااث مان المعلاوم أن األعمادة فاي المساجد النباوي فاي عهاد لنباي )ص(.النبوية, وارتياد جبريل )عليه السالم( على ا النبي محمد ) ص( كانت من الخشب, وورد أن ابا بكر الصديق )رض( رأى بعضها اكلته األرضة فابدل بهاا أعمااادة أخااارى مااان الخشاااب ولااام يغيااار مكانهاااا, وكاااذلك الخلفااااء الراشااادين الاااذين حاااددوا ووساااعوا المساااجد النباااوي يغيااروا مكااان أعمدتااه علااى ماار الزمااان, وهااو مااا تاارك للمساالمين فرصااة التعاارف علااى مكااان الشااريف بعااده لاام 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 األعمااادة هاااذه, وتاااوخي ماااا ورد فاااي أمكنتهاااا مااان فضااال وبركاااة و كراماااة. وظااال الخلفااااء اإلساااالم و ساااالطين لنباوي المسلمين وملوكهم يحرصون على إبقائها في أمكنتها, ويكتبون عليها أسماءها, كلما جدد بنااء المساجد ا الشريف. ماان جااذوع النخاال, وكاااان ( عماااوداً 95كاناات أعماادة المسااجد النبااوي الشاااريف فااي زماان النبااي ) ص ( ) . ثم جددها ابو بكر الصديق )رض( في خالفته حين نخارت, وزادهاا عمار الفااروق متراً 9,50ارتفاع الجدران الحجاارة المنحوتاة وزاد فيهاا )رض( . وبناهاا ذو الناورين عثماان )رض( ب( عماوداً 66)رضي اهلل عنه( فبلغات ) , ووضاع بهاا قطعاا مان الحدياد مغطااة بالرصااص المصاهور لتثبيات الحجاارة ماع بعضاها, ( عماوداً 55فبلغت ) مااع المحافظااة علااى أماااكن األعماادة الخشاابية التااي كاناات فااي زماان الرسااول )ص(, واسااتمرت حمااالت التوساايع حياث بلااغ عادد األعماادة علاى مااا ااا(ه7676_ 7604ام )والتطاوير بصاورة مسااتمرة وكانات التوسااعة األخيارة عاا عمااودًا منهااا مااا هااو متصاال بجاادران ومنهااا مااا هااو عمااود مسااتدير والاابعض منهااا لااه أطااواق 918يزيااد عاان م، تحمال تيجاناا مان البروناز زخرفات بزخاارف نباتياة جميلاة وغطيات قواعادها 6,5نحاسية ارتفااع الواحاد منهاا جااان بشااكل متناسااب ومتناسااق مااع نظيرهااا فااي التوسااعات السااابقة، وكساايت بالرخااام و صااممت األعماادة والتي بالرخاام األباايض المساتدير تعلوهااا تيجاان ماان البرونااز، داخلهاا مكباارات الصاوت، وفااي قواعادها فتحااات مغطاااة البارد القادم من محطة التبريد المركزية. ءالهوا بشبك نحاسي يخرج منها ظلاات األساااطين المبنيااة فااي زماان النبااي )ص( محافظااة علااى ومااع هااذه الزيااادات فااي المسااجد الشااريف أماكنهاااا، حياااث تحااارى ذلاااك كااال مااان زاد او رمااام فاااي المساااجد الشاااريف علاااى مااار التااااريخ، خاصاااة األعمااادة المشهورة الواقعة في الروضة الشريفة، التي ارتبط اسمها بمآثر مدونة في كتب الحديث والتاريخ وهي : تقااع فااي وسااط الروضااة الشااريفة، وقااد اتخااذ النبااي )ص( مكانهااا مصاالى بعااد و أسووطوانة السوويدة عائشووة: ، وكان أفاضل الصحابة والتابعين يفضلون الجلوس عندها. وسبب تسميتها ةتحويل القبلة، ثم تحول إلى مصال كمااا سااميت أيًضااا بأسااطوانة عائشااة )رض( أن بعًضااا ماان الصااحابة )رض( كااانوا جلوًسااا عنااد عائشااة )رض(. القرعة لرواية )القترعوا عليها بالسهام(. وروى بعض التابعين عن زيد بن أسلم أنه رأى موضع جبهة بأسطوانة ولهذا يعرف المسلمون فضل الصالة عند هذه األسطوانة. رسول اهلل )ص( عند هذه األسطوانة. يجلااس وهااي مالصااقة لشااباك الحجاارة الشااريفة، وهااي األسااطوانة التااي كااان النبااي )ص( أسووطوانة الوفووود: عناادها لوفااود العاارب القادمااة عليااه لكااي تبايعااه علااى اإلسااالم، وهااي التااي وقااع عناادها نااداء بنااي تماايم ماان وراء الحجرات، حيث نادوا رسول اهلل )ص(، وقالوا: "يا محمد اخرج لنا نفاخرك"؛ فأنزل اللَّاه تعاالى فاي شاأنهم قولاه: ااُرَج ِإلَااي9ِهم9 َلَكاااَن َخي9ااًرا َلهُاام9" "ِإنَّ الَّااِذيَن ُيَناُدوَنااَك ِماان9 َوَراِء ال9ُحُجاارَ اِت َأك9ثَااُرُهم9 ال َيع9ِقلُااوَن ل َولَااو9 َأنَّهُاام9 َصااَبُروا َحتَّااى َتخ9 (. وعند هذه األسطوانة أيًضا قدم علاى النباي )ص( ضامام بان ثعلباة وافادًا عان بناي ساعد بان 5-6)الحجرات: بكر. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 45 ، وموقعها الرابعة شرق المنبر، وهي األسطوانة التي ربط وتسمى أيضًا أسطوانة أبي لبابة أسطوانة التوبة: فيها الصحابي الجليل "أبو لبابة" األنصاري )رض( نفسه، وظل فيها أسيرًا، وقال: "واهلل ال أفك هذا األسر عان نفسي حتى يتوب اهلل عليَّ، ويحلني رسول اهلل )ص( بيده". وهذه األسطوانة مكتوب عليها حتى اآلن )أسطوانة ي لبابة( وُتعرف با"التوبة"، وتقع إلى الشرق من أسطوانة عائشة، وهذه األسطوانة أيضاًا هاي التاي َأَسار النباي أب )ص( فيها ثمامة بن أثال سيد اليمامة حين جاء به الصحابة في سرية أسيرًا؛ فأكرمه النبي )ص(. لةقووة )أي المطيبووة بطيووب الخلوووق(: صااقة لمصاالى النبااي )ص( ماان وهااي األسااطوانة المالاألسووطوانة الُمخَّ جهة القبلة، وكان النبي )ص( يصلي إليها بعد تحوله عن أسطوانة عائشة )رض(، ولكن هذه األسطوانة الياوم متقدماااة عاااان محلهااااا األصاااالي؛ إذ محلهااااا األصاااالي عاااان يمااااين اإلمااااام إذا وقااااف فااااي المصاااالى الشااااريف. وهااااذه ومكتااوب فااي أعالهااا: "األسااطوانة المخلقااة"، وساابب األسااطوانة اليااوم يرتكااز عليهااا المحااراب النبااوي الشااريف، تسميتها بذلك أن النبي )صلى اهلل عليه وسلم( رأى عليها نخامة فساءه ذلك؛ فقام أحاد الصاحابة وحاك النخاماة وطيب مكانها بطيب يسمى الخلوق؛ فُسرَّ النبي )ص( لذلك. )ص(، وكان يوضع له عندها سرير، وهي األسطوانة التي تقع في مكان اعتكاف النبي أسطوانة السرير: وكاااان هاااذا السااارير مااان جرياااد النخااال وفياااه الساااعف. وتقاااع هاااذه األساااطوانة شااارقي أساااطوانة التوباااة، وهاااي الياااوم مالصقة لشباك الحجرة الشريفة. وتقع خلف أساطوانة التوباة مان الشامال. ساميت باذلك ألن بعاض الصاحابة أسطوانة المحرس أو الحرس: اسة النبي )ص(. وكانت تسمى أيضًا أسطوانة علي بن أبي طالب )علياة الساالم(؛ ألناه كان يجلس عندها لحر ( 41كان يجلس عنادها حارساًا للنباي )ص(، فلماا نازل علياه قولاه تعاالى: "َواللَّاُه َيع9ِصاُمَك ِماَن النَّااِس" )المائادة: ترك الحراس حينئذ. ة الغربياة الشامالية مان الحجارة الشاريفة، وتقاع ساميت باذلك لوقوعهاا فاي ركان المربعا أسطوانة مربعة القبر، هذه األسطوانة داخل الحجرة الشريفة، وبالتالي ال يصلى عندها. وهي التي في مكان تهجده )ص( من الليل، وتقع أيًضا داخل الحجرة النبوية الشريفة. أسطوانة التهجد: :the symbolic dimension of the column البعد الرمزي للعمود ب اشبنغلر، ان الرمز يعاد ضارورة لمختلاف تجاارب اإلنساان، فكال ماا هاو موجاود يتطلاب اإلشاارة إلياه يرى برمز، ابتداء من الظواهر الفيزياوية وانتهاء بأشكال المعرفة والرياضيات والفيزياء المفترض ان لها سامة كونياة يصنعها الناس لتراكيب معينة أو شواخص خالدة. الرمزية تهتم بالمتعة المتولدة عن التداعيات التي يمتلكها أو من البيئة المبنية. وان الحاجة الرمزية هي عالقة معنوية مع شيء يخص هوية الفرد، ولايس عالقاة ماع مادياة الشيء او ملموسيته . وتؤلف اإلشارة الرمزية مقوما لهوية الفرد، لذا فان قبولهاا ال يمكان ان يفارض علياه لعادم للشاايء علااى التعاارف علااى شااكلية اإلشااارة وداللتهااا. ان اإلشااارة المعلوماتيااة ال تصاابح اقتصااار الحالااة الرمزيااة إشارة رمزية اال اذا تبناها الفرد واعتبرها مقوما لهويته. كما ان اختيار اإلشارة وجعلها رمزا هو عمل فكري لكنه 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 ، 7885و لااه )الجااادرجي،عفااوي باانفس الوقاات. ماارد ذلااك عاادم تقيااد الفكاار بشااكلية معينااة اذ انااه ينتقااي مااا يحلاا (، أي يمثاال البعااد الرماازي العالقااة الترابطيااة ماان حيااث عالقتااه بالهويااة، حيااث انااه يسااهم فااي 946-957ص تطمين متطلبات هوية الفرد او المجموعة نتيجة النطوائه على العقائد والعاادات، والعالقاات االعتبارياة بماا فاي زي فااي النتاجااات، فقاادت قاادرة النتاجااات فااي تطمااين هااذا المطلااب ذلااك الطبقيااة والتراتبيااة. فااإذا فقااد البعااد الرماا للمتلقي، وبالتالي فقد اإلحساس بالهوية. أما في الجانب االجتماعي فإن للرموز أهمية ال تقل شأنًا عما هي عليه في بقية الجوانب وما تخبرنا به في االلف الثالاث قبال المايالد، والتاي الوثائق و النصوص القديمة وتشير الوثائق األثرية عن ملحمة "كلكامش" تبين وعي أسالفنا وتصورهم لمسيرة التاريخ، وأن اإلنسان هو صانع التاريخ والبطل الحقيقي فيه، وهو صاحب اجتماعيااً الذكر الحسان والفعال الحمياد الشاجاع الماؤمن باروح الجماعاة، وباذلك أنهاا أضافت علاى البطولاة ُبعادًا خاااار هااااو البعااااد الرماااازي االجتماااااعي، أو يأخااااذ الرمااااز بعاااادًا تاريخيااااًا، حيااااث ُيعاااااد أي أن الرمااااز أعطااااى بعاااادًا أ "أوتوحيكااال" قائاادًا رمزيااًا للتحرياار فااي وادي الرافاادين ماان خااالل قيادتااه أقاادم حاارب للتحرياار عرفهااا التاااريخ حتااى ألماااة العربيااااة األن. فاااي حاااين أن الرسااااول محماااد صااالى اهلل عليااااه والاااه وسااالم ُيعااااد رمااازًا كلياااًا ساااارمديًا قدسااايًا ل واإلسالمية واإلنسانية حيث "كان رجاًل في أمة، و أمة في رجل" لما جبل عليه من صدق وأمانة وقايم أخالقياة نسانية وعظمة الشرف الرفيع الذي يتسم به)العتابي، .(767،ص6004وا َتَروَنهَاااا( , ترادفااات رمزياااة العماااود ماااع معجااازات أهلل كماااا فاااي صاااورة لقماااان ) َخلَاااَق ألَساااماَوات بَغيااار َعماااد واكتسااب اساام العمااود ايحاااءات فااي السااند واالعتماااد , ونعاات بااه المعتمااد والعمااد والعميااد . وتواشااج الغلااو فااي حجومااه رمزيااًا مااع الطغيااان كمااا فااي الااذكر الحكاايم ماان" سااورة ص " ) وَفرَعااُون ُذو أألوتَاااد(. أعماادة المصااريين اء. وقاد وردت بعاض األعمادة المصارية تخليادا آللهاتهم أو هي نوع من األعمدة الرمزية التي ال توظف في البنا .ملوكهم أو فرسانهم كالعمود األوزوريسي والعمود ذو الفارس المعروف باألطلنطي والعمود الهاتوري وغيرها تاانعكس الميثولوجيااا علااى األفكااار ال باال حتااى علااى المعتقاادات الروحيااة ، حيااث هناااك اعتقاااد " شااعبي" لشياطين تعايش وتفار باين أعمادة الخشاب فاي البياوت القديماة , حياث تشاكل تلاك األعمادة راسخ للعامة , بان ا مساند سقوفها، أو في المغاور، والشعاب، و األكوا المهجورة، وفي بقايا جادران المادن القديماة مثال ارم ذات رائب بابل التي العماد او خرائب قوم صالح، التي غضب أهلل فهلك من هلك وهجرها من مكث او في أعمدة خ هجرت بعد الخراب. وتعااد األعماادة فااي أالبنيااه العامااة وعلااى وجااه الخصااوص فااي األبنيااة الدينيااة مثااال مااا موجااود فااي مرقااد أإلمام علي ابن أبي طالب علية السالم في النجف االشرف ومرقدي األماميين الحساين و اخياة العبااس)عليهم ماااميين ألجااوادين ) عليهمااا ألسااالم( فااي الكاظميااة او بقيااة المراقااد السااالم( فااي كااربالء المقدسااة او فااي مرقااد األ المقدسة أو مساجد األولياء الصالحين فاان ووجاود األعمادة لاه داللاة رمزياة وتعبيرياة و روحياة كماا هاو بالنسابة ( 16،ص6079)مسجدالكوفة، عمود، 799 للعمود الخامس والسابع في مسجد الكوفة والبالغ عدد االعمدة فيه 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 هااي معالجااة مناخيااة. فااان مقياااس األعماادة وعااددها ذلك العمود)المياال( فااي وسااط مسااجد الكوفااة ،وأكثاار مماااوكاا واحاطتهااا بالمرقااد وعلااى حافااة رواق مسااقف يمهااد بااال شااك للاادخول إلااى أجااواء مقدسااة مهيبااة ويخلااق نوعااا ماان ر إلوى العموود أو إن الباحوث عنودما يشوي (.766، ص 6007الخشوع والرهبة بحكم صرحية المقياس)شهاب، إلى قوس أو القبة أو إلى أي مفردة أخرى من مفردات العموارة العربيوة فوان التدكيود يودتي مون كونهوا تشوكل جزء ال يتجزأ من ضمير األموة الجمعوي وكوذلك بقيوة المفوردات الخالودة فوي ذاكورة األموة باعتبوار العموارة رموزًا اجتماعيًا فضاًل عن المضامين االخرى. : the philosophical dimension of the column لسفي للعمودالبعد الف ج يمثاال البعااد الفلساافي جانااب ماان القاادرة الفكريااة التااي يااتمكن العقاال ماان خاللهااا ماان اإلدراك والتفكياار، مثاال المقارنااة بااين األشااياء وتمييااز خصائصااها. وان هااذه القاادرة متصاالة بطبيعااة العقاال اتصااااًل وثيقااًا بحيااث يسااتحيل ه وتكون األفكار الناشئة عنهاا غيار قابلاة للخطاأ. فاالفكر هاو نتااج التفكيار الاواعي المادرك. والعالقاة فصلها عن بين الفكر والتفكير عالقة معنوية والفاارق بينهماا ان التفكيار هاو الطريقاة التاي يعاالج بهاا الماخ معطياات الواقاع وقاوانين عاماة. التفكيار أذن ذاتاي، والفكار بينما الفكر هو النتيجة التي يصوغها المفكر في فرضيات ونظريات اجتماعي. وما نعنيه بالفكر هو القدرة على االستفادة القصوى من طاقة العقل لتجلية ما خفي من الحقاائق ماع األخذ في االعتبار إن العقل هو ملكاة التحليال والتعليال التاي تمياز باين الخطاأ والصاواب، أن الفكار هاو صاانع ن الحاادث كااان جنينااا تمخااض عنااه الفكاار، والعالقااة بااين الحاادث والفكاار هااي إن األول للحاادث وسااابق عليااه، وا يصاانع بوقوعااه إثااارة وتحريضااًا للتااالي لتوسااعة دائاارة عملااه. فااان العمااود يفهاام فلساافيا علااى انااه نحاات ساالبي ماان سااقف وتاارك الكتلااة الصااماء للبناااء, أو بقيااة باقيااة ماان األجاازاء المتضااامة لااه, بمااا يضاامن هندساايا رفااع هامااة ال لعزياز )َخلَاَق ألَساماَوات بَغيار َعماد اهلل تعاالى فاي محكام كتاباه افراغات المعيشة كغاية معمارية بحد ذاتها. قاال ( إي إن إعجاااز ألخااالق جاال شااأنه فااي خلااق هااذا الكااون ورفااع السااموات العااال طباقااا 70َتَروَنهَااا( ) سااورة لقمااان ها عمودًا ومن هذا نستنتج ان ماهية وطبيعة وظيفة العمود هي مزينتا بالنجوم والكواكب األخرى دون إن نرى ل في رفع السقف وقال ألمصطفى ) صلى أهلل عليه وسلم ( ) ألصالة عمود ألدين( ومن هذا نستشف ان كال ماا نريد أن يبقى قائما يجب أن يكون له عمودًا. :the educational dimension of the column البعد التعليمي للعمود ه اااِم َرب اااَك الَّاااِذي َخَلَق()ساااورة ( 7آياااة العلاااق، أن أول آياااة أنزلااات مااان القااارآن الكاااريم تاااأمر باااالقراءة ) اق9اااَرأ9 ِباس9 ويعتبر الذين يؤرخون للعلم اإلسالمي أن بدايته كانات هاي "علام الحاديث" مان حياث جمعاه وتدويناه. وقاد كاان تتفرع. ويذكر الدكتور علي أومليل "إال إننا يمكن أن نعتبر أن هذا في البدء هو "العلم" قبل أن تتعدد العلوم و الموضوع األول للعلم كان هو القرآن، من حيث قراءته وجمعاه. فالعلمااء األوائال كاانوا هام األفاراد الاذين أطلاق ه ( وفي هاذ97،ص7889عليهم اسم" القراء"، فهم أسالف العلماء المسلمين أو الرعيل األول منهم، ".)أومليل، 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 الفترة انطلق المسلمون من منطلق ان طلب العلم عبادة وان طلاب العلام فريضاة علاى كال مسالم، وعمااًل بقاول الرسول األعظم )ص( )اطلبوا العلم من المهد إلى اللحد( و )اطلب العلم ولو في الصين( وان )الحكمة ضاالة عليم في المسجد الكبيار فاي دمشاق ) المؤمن أنى وجدها فهو أولى الناس بها(، ويصف ابن بطوطة حلقات الت به جماعة من المعلمين لكتاب أهلل يستند كل واحد منهم إلى سارية من سواري المساجد يلقان الصابيان ويقارأهم ( نستنتج من ذلك ان الحلقات الدراسية والتعليمية كانت تعقد حول أعمدة المساجد فتخاتص كال حلقاة عناد كال قرآن او حلقة شرح ألقرآن وأخرى للخط أو التكتيب فضاًل عن الفقه وغيرها مان عمود بنوعًا من التعليم تلقين أل ( . 69،ص7881العلوم المختلفة )بهنسي، : the temporal dimension of the columnالبعد الميقاتي للعمود و ش يشكل الزمان مقوام واضح ذا داللة يؤكد في كل لحظة من لحظات الزمن على حالة الترابط التي يعي غير مجتزأ وغير قابل لالنفصال، وأن الحاضر اقتراناً المتلقي فيها، حيث يقترن الماضي بالحاضر بالمستقبل طبيعيًا للماضاي، إال أن الحادث هاو الاذي ياؤر لمرحلاة تاريخياة معيناة مناه والتاي علاى ضاوءها امتداداً يشكل ( حيااث أن الزمااان هااو مقاادار 96،ص6004،تأشاار حالااة التقاادم والتااأخر أو تؤسااس للقااديم والجديااد )العتااابي والتااي تؤكااد علااى قيمااة الزمااان فااي تكااوين ،(906،ص7818الحركااة ماان حيااث التقاادم أو التااأخر )الزنجاااني، لاااد للحظاااات متعاقباااة لكينوناااة الزماااان "التاااي تصااانع ورسااام واضاااح للمساااتقبل المحماااول فاااي رحااام الماضاااي الموا كرة الجمعية التي يعيشاها المتلقاي، لايس كلحظاة عاابرة طارئاة، بال الحاضر" الدائم الجديد حاماًل في طيااته الذا يعيشها كوحدة من الزمن الماضي والالحق، كوحادة متفاعلاة غيار مجتازأة، إنهاا تمانح المتلقاي الرؤياة التاريخياة التي يكتنزها في افقه ليكون عمق التاريخ مسرحًا وشاهدًا على ما حصل ال بهدف إعادة الماضي بل استثماره .(65،ص6004جميعًا ليشكل قراءة أصيلة لنص عميق)العتابي، لقاد أجاااد العاارب المسالمون معرفااة علاام الفلاك وحركااة اإلجاارام الساماوية بصااورة فائقااة ميازتهم عاان سااواهم من الشعوب وكذلك تمكنوا من صنع أدوات مختلفاة لمعرفاة حركاة الازمن حياث قاام الخليفاة هاارون الرشايد مان ل مااان ساااعة لمعرفااة الوقاات إال انااه رغاام هااذا التقاادم العلمااي و الصااناعي بقااي العمااود إهااداء ملااك فرنسااا شااار يشكل في العمارة العربية اإلسالمية أداة لقياس الزمن حتى االن و رغم حالاة التقادم التاي تعيشاها المجتمعاات سالمية ففي وسط مسجد العربية اإلسالمية إال أننا نجد لحد هذه اللحظة تواجد العمود في الكثير من المدن اإل الكوفة نجد حضور العمود ليقوم بوظيفة تحديد أوقات الصالة بكل دقاة مان خاالل مسااقط الظال والاذي يسامى فااي هااذه الوظيفااة بالمياال او الماازول، وكااذلك وموجااود فااي الاايمن فااي مسااجد الجنااد حيااث يقااع مسااجد الصااحابي كام شامال شارق بمديناة 66الجناد الواقعاة علاى بعاد الجليل معاذ بن جبل قي القسم الشمالي الشارقي مان مديناة تعز،ويعااود تأسيسااه الااى عهااد النبااي صاالى اهلل عليااه والااه وساالم حيااث يوجااد فااي صااحن المسااجد عمااود مربااع ارتفاعه متران ويستخدم كمزولة لتحديد اوقات الصالة . :ما تقدم نثبت االتي 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 41 جماال العمااارة العربيااة اإلسااالمية حيااث انعكااس أثاار أن العقياادة اإلسااالمية كاناات لهااا الحظااوة والتااأثير علااى م القرآن الكريم والسنة النبوية الشاريفة فضااًل عان الجواناب التشاريعية والقواعاد الفقهياة واألعاراف فشاكلت األساس التااي احكماات التنظياار والمفاااهيم المعماريااة، التااي اهتماات بمقدسااات المساالمين وباارزت هيمنااة المقاادس فيهااا ماان طية وعمرانية مما أضفى على مشهدها الحضري سمة الخشوع والجالل، فقبب الجواماع خالل خصائص تخطي و المنائر التي تبرز عمودياًا تاربط محاور الساماء بمحاور األرض، الاذي يثيار فاي الانفس الخشاوع، حياث شاكل نفااس هيمنااة البااروز العمااودي للقباااب و المنااائر كركااائز علااى خااط السااماء للمدينااة البعااد المقاادس للفضاااء وهااو اإلحساس الذي يتركه العمود في المباني الدينية بشكل عام. أن الميثولوجيا تنعكس على األفكار ال بل حتى على المعتقدات الروحية واالعتقادات الشعبية للعامة الناس، حيث رسمت المخيلة العامة للفرد، عنصر العمود بدالالت رمزية وتعبيرية أضفت أجواء مقدسة مهيبة وعًا من الخشوع والرهبة. و يمثل البعد الرمزي العالقة الترابطية من حيث عالقته بالهوية وبما أن تخلق ن العمارة تمثل الواجهة الضرورية التي تدرك من خاللها الشبكة المعقدة للعالقات االجتماعية والحياتية التي ينية والعقائدية، وليس من تصورات تستمد أسس تنظيمها وتطورها العفوي من األعراف والتقاليد والقيم الد شمولية نظرية، وتكمن أهمية التركيز بالدرجة األولى على البعد اإلنساني االجتماعي للعمارة والعمران ضمن مقتضيات الواقع الديني. يمثاال البعاااد الفلساافي جاناااب ماان القااادرة الفكريااة التاااي يااتمكن العقااال ماان خاللهاااا ماان اإلدراك والتفكيااار، مثااال ناة باين األشااياء وتميياز خصائصاها. وان هااذه القادرة متصالة بطبيعااة العقال اتصاااًل وثيقااًا بحياث يسااتحيل المقار فصاالها عنااه وتكااون األفكاااار الناشاائة عنهااا تتساام بقااادر ماان الدقااة. فااالفكر هاااو نتاااج التفكياار الااواعي المااادرك. الطريقة التي يعالج بها المخ معطيات والعالقة بين الفكر والتفكير عالقة معنوية والفارق بينهما إن التفكير هو الواقع بينما الفكر هو النتيجة التي يصوغها المفكر في فرضيات ونظريات وقوانين عامة. نجد ان الحضارة اإلسالمية العربية غنية بالقيم السامية التي اختصت بها العناصار المعمارياة فاي المجتماع ورًا مهمااًا فااي ترساايخ القاايم الدينيااة واالجتماعيااة والثقافيااة والروحيااة اإلسااالمي الشاااهدة علااى أن للعمااارة دائمااًا د داخاااال المجتمااااع والمجساااادة فااااي عناصاااار ماديااااة معماريااااة تااااتالءم فااااي تشااااكيلها مااااع جااااوهر ومضاااامون الاااادين اإلسالمي، كما أنها وسايلة للتعبيار عان خصاائص وسامات وقايم وتقالياد المجتماع وتعكاس روح التكامال وتعبار الساالوك االجتماااعي ونكااران الااذات والكاارم وحااب الخياار، فهااي مبااان وجاادت مصاااحبة لظهااور عاان التكافاال فااي اإلسااااالم السااااتيفاء أغااااراض وظيفيااااة نبيلااااة هاااادفها خدمااااة المجتمااااع وتقااااديم العااااون لااااه فااااي المجاااااالت الدينيااااة واالجتماعية والثقافية والفقهية والطبية والدفاعية والتجارية و العلمية والخيرية. مقااوام واضااح ذا داللااة يؤكااد فااي كاال لحظااة ماان لحظااات الاازمن علااى حالااة التاارابط التااي يعاايش ان الزمااان غير مجتزأ وغير قابل لالنفصال، وأن الحاضر اقتراناً المتلقي فيها، حيث يقترن الماضي بالحاضر بالمستقبل ناه والتاي علاى ضاوءها طبيعيًا للماضاي، إال أن الحادث هاو الاذي ياؤر لمرحلاة تاريخياة معيناة م امتداداً يشكل 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 تأشر حالة التقدم و التأخر أو تؤسس للقديم والجديد حيث الزمن يقاس بالحركة، وبذلك فان كينونة العمود هي التي تشكل ذلك الحدث التاريخي. :االستنتاجات-3 لقد بين البحث في استنتاجاته الخاصة بالمستويات الثالثة المحددة في الفقرة االستنتاجات الخاصة : 3-1 ( وهي: 5السابقة الى ان هناك ثالثة ابعاد رئيسة اهتم بها البحث، شكل) البعد اإلنشائي. البعد التاريخي البعد الديني. وقد تم تأشير المضامين التي خصت العمود من خالل التقاطعات بين األبعاد الرئيسية الثالثة: ة اإلساااالمية تكااااماًل فاااي كاااون العماااود عنصااارًا يتحقاااق فاااي الوظيفاااة اإلنشاااائية للعماااود فاااي العماااارة العربيااا أوال: معماريااًا أصاايال فااي بنيااة العمااارة العربيااة اإلسااالمية. وهااذا مااا يعطااي األبعاااد المتداخلااة فااي األبعاااد اإلنشااائية كااون العمااود عنصاار معماريااًا أصااياًل فااي بنيااة العمااارة العربيااة اإلسااالمية اسااتقى عمقااه والتاريخياة. ماان خااالل: يخي من نبع الحضارات المتالحقة. كما ان حضور العماود علاى المساتوى البيئاي والحضاري الحضاري و التار البعاااد هاااو حضاااور متاااداخل باااين هاااذين البعااادين باتجااااه البعاااد اإلنشاااائي المتحقاااق. بينماااا يتحقاااق التكامااال ماااع الجمعياة حضور مفاردة العماود فاي الاذاكرةإلظهار مضمون االجتماعي يمثل جزءًا أساسًا في كينونة المجتمع .للمجتمع وفي البنية المعمارية على المستوى العمراني أو ضمن النسيج الحضري يتحقااق فااي الوظيفااة اإلنشااائية للعمااود فااي العمااارة العربيااة اإلسااالمية تكاااماًل فااي كااون العمااود عنصاارًا ثانيووًا: اخلاااة فاااي األبعااااد اإلنشاااائية معمارياااًا أصااايال فاااي بنياااة العماااارة العربياااة اإلساااالمية.وهذا ماااا يعطاااي األبعااااد المتد والدينية. من خالل: إدراك إن للعقيااادة اإلساااالمية حظاااوة وتاااأثير علاااى مجمااال العماااارة العربياااة اإلساااالمية فاااي اساااتثمار العماااود روحيااًا؛ وقااد انعكااس أثاار القاارآن الكااريم والساانة النبويااة الشااريفة علااى األفكااار والمعتقاادات الروحيااة واالعتقااادات مااة الناااس، حيااث أثاارى العمااود المخيلااة العامااة للفاارد باادالالت رمزيااة وتعبيريااة؛ ويااتمكن العقاال فااي الشااعبية للعا قدرتااه الفكريااة ماان اإلدراك والتفكياار فااي المقارنااة بااين األشااياء وتمييااز خصائصااها؛ ومااا اختصاات بااه الحضااارة ساالمي، وبالتاالي يبارهن اإلسالمية العربية مان غناى فاي القايم الساامية عبار عناصار معمارياة فاي المجتماع اإل الزمان كونه رابط يعيش المتلقي فيه من خالل اقتران الماضاي بالحاضار بالمساتقبل اقتراناا غيار مجتازأ وغيار قابل لالنفصال والذي ينعكس في تكوين خصوصيته هويته المعمارية. الناتجة في: تتحقق العالقة المتداخلة بين البعد التاريخي والديني في إظهار المضامينثالثًا: 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 إحكام التنظير والمفاهيم المعمارية، التي اهتمت بمقدسات المسلمين وبارزت هيمنة المقادس فيهاا مان خاالل خصائص تخطيطية وعمرانية تؤثر على مشاهدها الحضاري، عكسات أصاالة العماود ورياديتاه فاي بنياة العماارة دة و فااي طاارز معماريااة أشاارت خصااب االنتماااء العربيااة اإلسااالمية والااذي أنعكااس فااي األشااكال األولااى لألعماا وامتالك خصوصيته و وحدته وأنماطه التي حققت هويته المعمارية. أضافت األبعاد الداللية والرمزية والتعبيرياة والروحياة للعماود فاي المخيلاة العاماة للفارد، اجاواء مقدساة مهيباة لعمارة العربية اإلساالمية عبار تشاكيل الجواناب تخلق نوعًا من الخشوع و الرهبة. انعكست سريعًا على مجمل ا المادية والتعبيرية والداللية والروحية من جهة وتأكيد البعد والمضمون الجمالي المتقدم من جهة أخرى. ارتباط القدرة الفكرية للعقل في اإلدراك والتفكير بالمقارنة بين العماود وبااقي التكويناات األساساية للعماارة إال اًل وثيقًا يصعب فصله وتكون األفكاار الناشائة عنهاا. بفعال الحيااة المادياة والفكرياة لنتااج األساالف هناك اتصا مما ساعد على تنمية القدرات اإلبداعياة عبار تنااول الفناون الجمالياة و القيمياة و اساتيعاب الادالالت والمعااني الروحية والرمزية في تقبل المفاهيم المعاصرة. رساايخ القاايم الدينيااة واالجتماعيااة والثقافيااة داخاال المجتمااع والمجساادة فااي عناصاار ماديااة للعمااارة دور فااي ت معمارية تتالئم فاي تشاكيلها ماع جاوهر ومضامون الادين اإلساالمي، وتكاون بصايغ تعبيرياة تكاملياة فاي سامات رياة ودورة فاي وقيم وتقاليد المجتمع. من خالل حضور العمود فاي الاذاكرة الجمعياة للمجتماع وفاي البنياة المعما تشكيل السياق الزمكاني. التأكياااد علاااى حالاااة التااارابط التاااي يعااايش المتلقاااي فيهاااا، مااان خاااالل اقتاااران كامااال باااين الماضاااي بالحاضااار بالمستقبل. من خالل حضور متداخل بين البعد البيئي والحضري لتشكيل فضاءات بينة)بين الداخل والخارج( جي.بحيث تكون بشكل معالجات للفضاء الخار االستنتاجات العامة: 3-2 لم يستعمل العماود فاي العماارة العربياة اإلساالمية بكثارة كعنصار تصاميمي بصاورة منفاردة )شااخص( او .7 كمجموعة من األعمدة مثل ما استعمل في العمارة الغربية بصورة واسعة. لحضااااري و شاااكل العماااود عنصااار معمارياااًا أصاااياًل فاااي بنياااة العماااارة العربياااة اإلساااالمية اساااتقى عمقاااه ا .6 التاريخي من نبع وعمق الحضارات المتالحقة. ان العمااود فااي العمااارة العربيااة اإلسااالمية لاام ينظاار إليااه علااى أساااس انااه عنصاار ذو وظيفااة إنشااائية فقااط .9 مجارد ماان غنااه وثااراه بال اسااتطاع الباوح عاان مكنوناتاه الدالليااة والتعبيرياة وتوظيفهااا رمزياًا وفلساافيًا ودينيااًا وحضريًا وتاريخيًا وتعليميًا واجتماعيًا وميقاتيًا وتراثيًا. وروحيًا وبيئياً أن العمااود فااي العمااارة العربيااة اإلسااالمية ) العمااود البغاادادي )) الاادلك (( أو )العمااود األندلسااي( لاام يأخااذ .6 مااداه الحقيقااي فاااي االسااتعمال فااي الفضااااءات الحضاارية وضاامن النسااايج الحضااري لألغااراض البيئياااة أو ها من اإلغراض بشكل واسع.الحضرية أو غير 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 ان العماااود فاااي العماااارة العربياااة اإلساااالمية علاااى الااارغم مااان كثااارة مكنوناتاااه وثاااراءه فاااي دالالتاااه الرمزياااة .5 والتعبيريااة إال انااه لاام يعتمااد وحاادة قياسااية نموذجيااة تتكاارر بشااكل تمكننااا ماان اشااتقاق نسااب قطاار وارتفاااع العمود والتي تنعكس على تحديد نسب عناصره. لرغم من كثرة استعمال العمود في العمارة العربية اإلسالمية العمود البغدادي / الدلك ونمط األبنياة على ا .4 التي اساتعمل فيهاا لام تاتح لاه إن يتطاور مقارناة باالعمود األندلساي , بال علاى العكاس فاان كثارة اساتعماله ساارعة وسااهولة التنفيااذ فااي نمااط األبنيااة السااكنية دفعاات إلااى تبساايطه وتجريااده باادافع عواماال اقتصااادية و ونوعية المواد المستعملة مما افقده الكثير من مضامينه وغناه وثراءه الداللي التعبيري. شاكل العماود عنصاارا نحتياا منااذ القادم وبغااض النظار عاان طبيعاة المااواد المصانوع منهااا ساواء القصااب او .1 تكنولااوجي سااهلت إمكانيااات الخشااب او الحجاار أو األجاار أو ماان الرخااام والمرماار فااان تااأثيرات التطااور ال إعااااادة اسااااتعمال العمااااود فااااي العمااااارة بمااااواد جدياااادة بصاااافة كعنصاااار إنشااااائي أو تزيينااااي جمااااالي وباااانفس المضامين واإلبعاد التعبيرية والداللية وبأقل التكاليف المادية والفنية. لتاااااج( و ذات إن العمااااود البغاااادادي )الاااادلك( يتضاااامن العناصاااار األساسااااية المكونااااة لااااه )القاعدة،الباااادن، ا .9 عالقات تناسبية منتظمة على غرار العمود الكالسيكي في العمارة الغربية، وذلك بتأثير المنظومة القيمية التماثال...( فضااًل -التكارار-االنتظاام-الوحدانياة-اإلسالمية والتي تتضمن مجموعة من المفردات)التاوازن عاااد الشااكلية للعمااود ومجماال العمااارة العربيااة عاان تااأثير البعااد الااديني الروحااي التوحياادي الفكااري علااى اإلب اإلسالمية. إن العمود في العماارة العربياة اإلساالمية لام يأخاذ بمفهاوم محاكااة جسام اإلنساان ال مان حياث المنظوماة .8 التناسبية وال الشكلية في استعمال هيئة اإلنسان كعمود، مثل ما موجود في العمود في العمارة الغربية. مود في العمارة العربية اإلسالمية لإلغراض النصبية او كشاخص في الساحات العامة.قلة استعمال الع .70 لقد وفرت إمكانيات استعمال األعمدة في العمارة العربية اإلسالمية من تحرير الكتلة البنائية الصماء او .77 ن األنماط ما يسمى بالصندوق البنائي األصم فضاًل عن كونه ابداعًا اصياًل ساهم في خلق مجموعة م العمارة العربية اإلسالمية. دعم استعمال األعمدة في العمارة العربية اإلسالمية التقليل من قابلية االعتماد على الجدران الحاملة .76 مما إضافة إمكانيات إنشائية وسعت من سعة الفضاءات المعمارية فضاًل عن تقليل الكلف االقتصادية. (court yard)مارة العربية اإلسالمية على بنية الفناء الوسطيلقد إضافة استعمال األعمدة في الع .79 مجموعة من الجوانب الجمالية و اإلنشائية فضاًل عن الجوانب األخرى وبذلك حركت من سكونية و رتابة شكل الفناء المألوف منذ القدم. 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 كوين ألتأريخي يعد العمود واحدة من المفردات أو العناصر المعمارية ذات الحضور المتميز في الت .76 للسمات والمميزات أو الخواص المعمارية والتي أسهمت في إنضاج وتشكيل الخصوصية والهوية للعمارة العربية اإلسالمية. تشكل األعمدة اطارًا خارجيًا محددًا لحافات الفناء عن الجزء المسقف )الطارمات( حيث تشكل .75 جزء المكشوف واألخر المغلق.فضاءات انتقالية ) مسقف مفتوح على الفناء( بين ال أوحى استعمال األعمدة بشكل منتظم وبإعداد كبيرة في قاعات الصالة والمساجد الواسعة في سامراء -74 وقرطبة وغيرها من المدن العربية اإلسالمية في فكرة الفضاء المنساب الممتد والمستمر والذي يتطابق مع لحداثة والذي عبروا عنه فيما بعد بالفضاء المستمر اي طبيعة وظيفته.والذي التقطه منظري عماره ا بتشابه معالجات الفضاءات وبساطتها ةبعد الحداث االستمرارية بين الداخل والخارج في حين جاء فضاء ما حيث عكست تساوي المعالجات في الفضاءات وعدم تميزها عن بعضها رغم اختالف الوظيفة حيث اصبحت دان االرتباط الزمكاني في المجتمع .عارية التجريد إلى حد فق أكدت كينونة العمود في المسجد على اصالة نمط المسجد في بنية العمارة العربية االسالمية منذ النشأة -71 االولى للمسجد النبوي ولحد االن، حيث جاء استعمال العمود كحل انشائي في دعم تسقيف الفضاءات فيها مئات االعمدة مما يدلل بشكل ال لبس فيه على تلك االصالة، الواسعة جدًا للمساجد والتي استعمل ويدحض في ذات الوقت طروحات المستشرقين التي تدعي بان المسجد هو تقليد لعمارة الكنائس المسيحية، علمًا بان الكنائس في اغلب االحيان تخلو من وجود االعمدة فيها وذلك لصغر كتلتها البنائية، في حين يشكل د جزءًا اساسيًا في الهيكل االنشائي للمسجد وذلك لسعة فضاءاته الستيعاب االعداد الكبيرة من العمو المصلين. المصادر:-4 القرآن الكريم. -أوأًل الكتب والدراسات والدوريات العربية. –ثانيًا ة أومليل؛ د. علي؛ السلطة الثقافية والسلطة السياسية؛ مركز دراسات الوحدة العربية؛ الطبع (7 م.7889الثانية؛بيروت م.6076،نيسان 5بدوي، محمد، االندلس ابداع واصالة، مجلة انا معماري،العدد (6 م.6005البعلبكي، منير؛ المورد، قاموس انكليزي_عربي؛ دار العلم للماليين؛بيروت، (9 بهنسي، د.عفيف؛ جمالية الفن العربي؛ المجلس الوطني للثقافة والفنون واآلداب _الكويت. (6 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 سي، عفيف؛ "من الحداثة إلى ما بعد الحداثة في الفن"؛ دار الكتاب العربي؛ الطبعة األولى؛ دمشق؛ البهن (5 م.7881 م.6005ثويني، علي، معجم عمارة الشعوب االسالمية، بيت الحكمة،بغداد، (4 الجادرجي، رفعت ؛ حوار في بنيويه الفن والعمارة؛ رياض الريس للكتب والنشر، لندن /بيروت/قبرص، (1 م.7885طبعة األولى، ال ، مركز دراسات الوحدة العربية، 699الجادرجي، رفعت، "العمارة المقدسة"، مجلة المستقبل العربي، العدد (9 م.7889بيروت، جواد علي ,مختصر تاريخ العرب ,الجزء الرابع ,قرص مدمج. (8 يصدرها المركز الجوبيراوي، جبار، بيوت سكان االهوار في ميسان ، التراث الشعبي، مجلة شهرية (70 م.7815الفولكلوري،وزارة اإلعالم،العدد السادس،السنة السادسة،بغداد -جودي، محمد حسين، نحو استراتيجية جديدة في تدريس الفن والتربية الفنية،الطبعة األولى (77 م.6076بغداد درها الحجية،عزيز جاسم،معالم بغدادية اختفت في البناء الحديث، التراث الشعبي، مجلة شهرية يص (76 م.7815المركز الفولكلوري،وزارة اإلعالم،العدد السادس،السنة السادسة،بغداد م.7886حسن عبد الوهاب، تاريخ المساجد األثرية، ،الهيئة المصرية العامة للكتاب، (79 الدراجي، د. حميد محمد حسن، االعمدة والتيجان في العمارة التراثية،دائرة التراث العامة، دار (76 م.6001الطبعة االولى، بغداد المرتضى للنشر، رزوقي، غادة موسى، حسن، شذى عباس، الفضاء المعماري في مملكة الحيرة والحكم الساساني (75 م.71،6077،كانون االول،مجلد4أنذاك، بحث مستل، مجلة الهندسة، العدد الزنجاني، ابراهيم الموسوي؛ كشف المراد في شرح تجريد االعتقاد؛ تصنيف نصير الدين محمد (74 ها ؛ شرح جمال الدين الحسن بن يوسف ابن علي الحلي المتوفي 416الحسن الطوسي المتوفي سنة م.7818ها؛منشورات مؤسسة االعلمي للمطبوعات بيروت164سنة السلطاني, د . خالد العمارة في العصر األموي االنجاز والتأويل ,الناشر دار المدى للثقافة والنشر, (71 م.6004الطبعة االولى بغداد م.6007الشرقي،طالب،القصور العربية االسالمية في العراق، دار الشؤون الثقافية ،العراق،بغداد، (79 شهاب، حسين علي؛ العمود في العمارة، دراسة تحليلية لنشؤ العمود وتطور دالالته المادية والتعبيرية (78 معماري عبر العصور؛رسالة ماجستير غير منشوره،جامعة بغداد،كلية الهندسة ،القسم ال م.6007؛بغداد،نيسان 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 45 عبد الرسول، سليمة؛ المباني التراثية في بغداد، دراسة ميدانية لجانب الكر ؛ المؤسسة العامة لآلثار (60 م.7891والتراث، وزارة الثقافة واإلعالم ،بغداد، العتابي , د. مهدي صالح فرج, األصالة في العمارة المعاصرة ,أطروحة دكتوراه غير منشورة ,قسم (67 م.6004لهندسة المعمارية,الجامعة التكنولوجية ,بغدادا م.6076،نيسان5عقل، لمى، المسجد االقصى الشريف عمارة وحقيقة وتاريخ،العدد (66 م.7889عالم، نعمت اسماعيل؛ فنون الشرق االوسط في العصور االسالمية؛ دار المعارف بمصر (69 وس برس؛ الطبعة األولى، غالب، الدكتور عبد الرحيم؛ موسوعة العمارة اإلسالمية؛ جر (66 م.7899بيروت م. 7896فتحي،احسان ، وارن ،جون ؛البيوت التقليدية في بغداد،لندن (65 قديفة، مالك صبري، صورة العمارة العراقية قبل االسالم، اطروحة دكتوراه غير منشورة، كلية الهندسة (64 م.6004،جامعة بغداد، د درويش؛ دار المأمون للترجمة والنشر؛ وزارة لويد؛سيتن؛ فن الشرق االدنى القديم؛ ترجمة محم (61 م.7899الثقافة واالعالم ؛بغداد محمد مكية، يتحدث عن "االسس االخالقية في العمارة"، كامران قرة داغي، مجلة فنون عربية، العدد (69 م.7896، سنة 5 م.6079مسجد الكوفة، فضل واعمال، امانة مسجد الكوفة، الطبعة الخامسة،الكوفة (68 م.7895ن الباحثين العراقيين ,حضارة العراق ,الجزء التاسع ,بغداد نخبة م (90 يوسف، شريف؛ تاريخ فن العمارة العراقية في مختلف العصور؛ منشورات وزارة الثقافة واالعالم؛ (97 م. 7896(؛دارالرشيد،يغداد68السلسلة الفنية) االنترنت-ثالثُا: . 6006ثة رفعة الجادرجي، االنترنيت/ ثويني، علي، تراثية محمد مكية وحدا-96 [http://www.alefyaa. comindex.asp? fname= news %5c2003 %5c08 %5c03_8 %5ccol %5c207.htm &storytitle= qqq%d8%af االنترنيت/ ليدي درور رحلة إلى أهوار العراق محاضرة؛ ليدي درور في الجمعية الملكية -99 م.6006االسيوية/باحثة ومستشرقة بريطانية 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 ( النماذج التسعة للعمود البغدادي / فتحي 6شكل ) 46ص)البيوت التقليدية في بغداد (–وجون ( يوضح االنواع االربعة لتيجان األعمدة 9شكل) المصدر شهاب حسين في العمارة االندلسية / 799ص/ (4الشكل ) مسجد الرسول )ص( في المدينة )السلطاني: (444خالد،ص 4202 2العدد 7مجلة القادسية للعلوم الهندسية المجلد 44 المستوى الثاني ثالثالمستوى ال ( مستويات األبعاد ومضامين العمود،)المصدر، 4شكل) الباحث( عمود في العمارة العربية اإلسالميةال بعد ااالنشائي للعمودال المستوى األول -البعد التراثي -الحضريالبيئي و -بعد التاريخي/ الجماليال االجتماعي الفلسفي -ألميقاتي -التعليمي -بعد الديني والروحي/ الرمزيال البعد اإلنشائي التاريخيالبعد الدينيالبعد االستنتاجات العامة / المصدر ( األبعاد الثالثية 5شكل) الباحث template for academica science journal journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 293 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. speed control of dtc-svm for induction motor drive using self-tuning fuzzy pi controller ann anfis rawaa kadhim sakran electrical engineering department, university of basra, email : rawaa.eep@gmial.com assist. prof. dr. khearia a. mohammed ali electrical engineering department, university of basra. email : khearia_ibrahimy@yahoo.com abstract: this paper deals with the performance analysis of three phase induction motor (im) with direct torque control based space vector modulation (dtc-svm). the dtc-svm scheme is a kind of high-performance control of im drives to improve the ripples of torque and flux in steady state, which one drawback of conventional dtc. dtc-svm has three proportional-integral (pi) controllers, one used as the pi speed controller and other pi flux controller and pi torque controller, which are utilized to produce the stator voltage references (𝑉𝑑𝑠 and 𝑉𝑞𝑠) respectively. to improve the performance of motor we used the self-tuning fuzzy pi (stfpi) controller and adaptive neuro fuzzy inference system (anfis) controller instead of pi controllers in dtc-svm. the simulation results carried out using matlab/simulink software package show that the response of speed motor with anfis is improved, more robustness, and reaches to the reference value faster than a conventional pi controller and stfpi controller and also reduced the torque ripple and less steady state error. keywords: induction motor, dtc-svm, pi controller, self tuning fuzzy pi controller, anfis. introduction this induction motors (ims) are broadly utilized, particularly poly phase ims, which are commonly utilized in industrial drives. ims are now the favorite option for industrial motors in accordance with their robust building, nonexistence of brushes and thanks to modern power electronics that are able to the control of the motor speed [1]. the im control was treated with different techniques. this contains simple linear techniques for example direct torque control (dtc), field oriented control (foc) and more complicated nonlinear techniques for example input-output linearization back stepping, sliding mode and passivity. most of the suggested controllers utilize the speed sensor and require the constant the motor parameters. this hypothesis leads to poor control performances, particularly through transient operation. the common of these controls require utilization of coordinate transformation, whereas dtc approach can be utilized to directily control for flux and torque without current controllers [2]. the dtc method was first suggested for im. dtc method for medium and low power applications is presented by takahashi and noguchiand, while dtc method for high power applications is presented by depenbrock and it is commonly utilized in industry [3]. conventional dtc usages the magnitude errors of the stator flux and torque as the inputs for hysteresis comparators to determine the voltages of stator vector ( vqs and vds) are applied to terminals of the motor. the complex plane is divided into 6-sectors, and a switching table is purposed to get the required vector based on the outputs of the hysteresis comparators [4]. the most common drawbacks of conventional dtc are a high ripple of torque and slow transient response to torque changes during startup. the performance of torque is improved by developed several techniques. one of the developed techniques utilized for reducing the ripples is dtc with space vector modulation (svm). svm was first suggested by a researchers group from germany in 1980s. journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 294 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. svm techniques offer several benefits, including the torque ripple is less, better dc bus utilization, less losses of switching, minimum total harmonic distortion (thd) in the ac motor current and easier implementation in digital systems [3]. in dtc-svm approach, the pi controllers are utilized instead of the hysteresis comparators for torque and flux in conventional dtc. however, the main disadvantages of dtc-svm with a simple pi controllers are the performance sensitivity to variations of the system parameters and the insufficient rejection load changing and external disturbances [5]. the disadvantages of the conventional pi controllers are performance sensitivity to covariance in parameters of the system, and the actuality that when utilizing fixed of the controller gains may not offer the required performance of speed under covariance in the operating conditions and parameters of the motor [6]. flc can be utilized to eliminate the disadvantages of conventional pi controller [7]. flc has demonstrated its effectiveness in non-linear, complex and inaccurate processes which it is impossible to utilize the standard model based control techniques impractically [8]. flc based intelligent controller can be utilized instead of the pi controller. flc has some advantages over conventional controllers such as simplicity of control, low cost, and the capability to design without knowledge the precise mathematical model of the plant [9]. flc is utilized in the controller design autonomously or hybrid with pi controller. flc provides faster control and superior but the major problem of design is to specify a consistent and complete set of rules and in the form of membership functions (mfs). a lot of trials and errors must be made to get the desired response that takes a long time [10]. the artificial neural networks (anns) have the advantages of very fast parallel computation, impunity from input harmonic ripples and fault tolerance characteristics [11]. however, ann only is inadequate if the training data are not adequate to deal with all the operating modes. the disadvantages of flc and ann can be eliminated by the usage of anfis [10]. anfis is a fuzzy scheme that usages a learning procedure resulting from the principle of ann to know its parameters (fuzzy sets and rules) by dealing with data examples. by mingling both flc and ann, it is probable to obtain the benefits of together controls in one implementation [12]. there are several studies related to dtc_svm and pi controller ,stfpi controller and anfis such as: in 2010 fayez g. areed, e.t al., suggested a direct torque of the im drive controlled by anfis. the suggested control scheme employs amplitude of the stator flux and the torque errors by using an anfis to change the angle and the amplitude of the required reference voltage. the simulation outcomes by utilization anfis are compared with the conventional dtc. the comparison results of dtc with anfis showed a reduction in the ripples of torque and flux in transient and steady-state response and fast stator flux response in the transient state [13]. in 2013, arun kumar r, and febin daya j. l., compared between conventional pid, fuzzy, and stfpid controllers based speed control system for a current source pwm inverter fed ifoc of im drives. in this study, the pi control system was substituted by stfpid based intelligent controller. the flc uses various forms of membership functions (mfs) for all parameters in order to obtain an efficient controller. by comparing the results with the pid and flc, these results showed that the suggested stfpid controller recognizes a good performance at the sudden variations with a quick settling time. as well, it has no overshoot and better behavior than flc and pid controller [14]. in 2015, a. durga bhavani, et. al., presented an intelligent control scheme with anfis controller to regulate the speed of the dtc of im drive. the performance of conventional dtc in im drives containing pi controller has a complex tuning and overshoot. therefore, this controller employs the error that obtained from the reference speed and estimated speed which produces the estimated torque and compared with the actual torque. the suggested anfis based im drive is providing better performance and provide less thd in steady state current ripple when compared with conventional dtc algorithm [15]. 1. induction motor modeling the equivalent circuit of the squirrel cage induction motor (scim) in (d−q) axis is shown in fig.1. the three phase voltage stator of an im can be given by the following equations [16]. va=vm sin(ωt) (1) vb=vm sin(ωt− 2π 3 ) (2) vc=vm sin(ωt+ 2π 3 ) (3) these three phase balance voltages are transferred into the two phase stationary reference frame of (d−q) axis. this can be given by eq. (4) and eq. (5). journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 295 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. [ vα vβ ] = 2 3 [ 1 −1 2 −1 2 0 √3 2 −√3 2 ][ va vb vc ] (4) then, the voltage in the (d−q) axis [ vd vq ] = [ cosθ sinθ −sinθ cosθ ][ vα vβ ] (5) figure 1 equivalent circuit of scim in (d−q) the mathematical model of threephase scim in the stationary reference frame (d−q) can be given by the following eqs. [17]. vds=(rs+pls)ids+plmidr−ωψds (6) vqs=(rs+pls)iqs+ωψqs+plmiqr (7) vdr=0= (rr+plr)idr+ plmids−(ω−ωr)ψdr (8) vqr=0=(rr+plr)iqr+(ω−ωr)ψqr+plmiqs (9) ls=lls+lm & lr=llr+lm (10) where ψds , ψqs are the stator flux linkages in the (d−q) frame in eq.(11) and ψdr , ψdr are rotor flux linkages in the(d−q) frame in eq.(12) , while p=d/dt. ψqs=lsiqs+lmiqr & ψds=lsids+lmidr (11) ψqr=lriqr+lmiqs & ψdr=lridr+lmids (12) the torque and speed can be determined as following equations [17,5] tem= 3 2 p 2 lm(iqsidr−idsiqr) (13) tem= 2 p jpωr+tl (14) dωr dt = p 2j (tem−tl ) (15) where vds , vqs, and vdr , vqr are the voltages for stator and rotor in the (d−q) frame respectively, while rs, rr, ωr, ω are stator resistance, rotor resistance ,rotor angular speed, and the electrical angular speed respectively. the stator, rotor and mutual inductance are ls, lr and lm, respectively. + vdr lm lm vqr vqs vds ids rs −ωψds+ lls llr +(ω−ωr)ψdr− rr idr iqs rs +ωψqs− lls llr −(ω−ωr)ψqr+ rr iqr + journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 296 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2. direct torque control with space vector modulation (dtc-svm) dtc usas the hysteresis band to directly control the torque and flux of the machine. the main benefits of dtc are the rapid response for torque and robust, no requisites for coordinate transformation no requisites for current regulators and pwm pulse generation. the main drawback of the dtc drive is the ripples of the flux and the torque in steady state. the torque and flux pulses impact the accuracy of the speed estimation. there are two approaches to reduce the ripples for flux and torque of the dtc drives. the first approach is multilevel inverter and the second approach is svm. in the first approach, the complication and the cost will be rised while in the second approach the ripples of flux and torque can be decreased [4]. the suggested dtcsvm system that is shown in the fig. 2 has used three pi controllers for processing errors of speed, flux and torque. the torque reference (te ∗) is generated by speed error, that it is processed through the pi speed controller ,while the pi flux controller and pi torque controller are producing the command voltages vds and vqs respectively [18]. figure 2 the suggested dtc_svm with pi controller the flux estimator model is dependent on stator resistance (rs) only, the stator flux linkages ψds and ψqs can be determined from eq.(16) and eq.(17) respectively, while the magnitude of the stator flux linkage ψs and the phase angle of the stator flux linkage θs are given in eq.(18) and eq.(19) respectively [19]. ψds=∫(vds−idsrs)dt (16) ψqs=∫(vqs−iqsrs)dt (17) ψs=√ψds 2+ψqs 2 (18) θs= tan −1 ψqs ψds (19) 3. pi controller proportional-integral (pi) controller is easy to design, simple structure and low cost. it is most broadly utilized in industrial application because of these benefits for pi controller. the output signal of pi controller consists of a sum of errors and the integral of that errors [7]. the transfer function for pi controller is given by eq.(20) u(s) e(s) =kp+ ki s (20) torque and flux estimator svpwm 3-phase vsi 𝑎𝑏𝑐 𝑑𝑞 𝑑𝑞 𝛼𝛽 𝑉α 𝑉β vqs vds 𝜓𝑠 ∗ 𝑇𝑒 ∗ 𝜔𝑟 ∗ 𝜓𝑠 𝑇𝑒 ω𝑟 pi pi pi + + + 𝐼𝑀 𝜃𝑠 journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 297 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. where: kp & ki are the proportional and the integral gains respectively, u(s) is the output control signal which represents torque reference (te ∗ ) in dtc-svm drive and e(s) is the error which represents the difference among the desired and the actual of motor speed and it is specified by eq.(21) e=ωr ∗−ωr (21) the proportional controller will decrease the steady-state error and rise time. but, will never remove the error. the integral control will decrease the error close to zero. but, it has a negative effect on the response of the speed and overall stability of the system [20]. 4. self-tuning fuzzy pi (stfpi) controller the stfpi controller is a mixture from the concept of fuzzy logic and the conventional pi controller [20]. flc utilized to tune the parameters of the pi controller; it gets scaled values of the error (e) and change of error (de/dt). its output is updating the parameters of pi controller based on a set of rules to keep good control performance even in the existence of drive non-linearity and variation of parameters. [13,14]. the flc is comprised of four main stages: fuzzification, knowledge base, decision making and defuzzification as demonstrated in fig.3 [21]. fuzzy model is a collection of if – then rules with indistinguishable predicates that use a fuzzy reasoning such as mamdani and sugeno models. mamdani type systems can be utilized to model any inference system in which the output membership functions (mfs) are either linear or nonlinear whereas sugeno type produces either linear or constant output [14]. the performance of stfpi controller can be shown as following [4]. 1dynamically adjusts the pi controller parameters to guarantee the stability of system over the wide speed range. 2fast response of speed. 3small errors for steady state and less overshoot. figure 3 block diagram of flc the fuzzy tuner has two inputs (e & de/dt) and two outputs: kpf a& kif . the structure of stfpi controller is shown in the fig.4. knowledge base interference mechanism fuzzification defuzzification 𝑑𝐸/𝑑𝑡 𝐾𝑝 𝐾𝑖 𝐸 journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 298 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 4 the structure of stfpi controller the equations for the stfpi controller process are given below[21]. te ∗=kpnew e(t)+kinew ∫e(t) dt (22) kpnew =(kp +kpf )∗∝ (23) kinew =(ki +kif )∗∝ (24) where: ∝ is the scaling factor is obtained from the flc. 𝐾𝑝𝑓 & 𝐾𝑖𝑓 are obtained from the flc, while 𝐾𝑝𝑛𝑒𝑤 & 𝐾𝑖𝑛𝑒𝑤 are the new gains of pi controller 5. adaptive neuro-fuzzy inference system (anfis) anfis put forward by jang in the early 90s, mixing the concepts of flc and anns to form a hybrid intelligent system that improves the capability to learn and adapt automatically [8]. anfis is one of the best reciprocating among ann and flc, which provides the adaptability and interpolation in accordance with the ann and smooth control in accordance with the flc. some of the benefits of anfis are compactness of model, they require a faster convergence and less size of training set than typical feed forward neural network. the nonlinear cartographical in a anfis is obtained by utilizing a fuzzy mf based ann [10]. the anfis is an adaptive network multilayer in fig.5. there are two different types of nodes according to their features: square (adaptive) nodes and circular nodes. the first type contains parameters, while the second type has no paramters [22]. the fuzzy inference system (fis) usually utilized in anfis is first order sugeno fuzzy model due to its easiness, efficiency of computational and built-in optimization techniques and adaptation [23]. the sugeno fis is like to mamadani format but that the output mfs are singleton spikes instead of a distributed fuzzy set. utilization singleton output simplifies the defuzzifiation step [24]. anfis system uses the following rule base [23]. if x is a1 and y is b1 then f1= f1(x,y) = a1x + b1y+ r1 (25) if x is a2 and y is b2 then f2= f1(x,y)= a2x + b2y+ r2 (26) f = w1f1+w2f2 w1+w2 =w̅1f1+w̅2f2 (27) where ai and bi are linguistic variables, while ai , biand ri are constants the anfis comprises five layers; the functions of these layers can be listed below [25]. layer1: every node of this layer transforms the input signal x or y utilizing mf (fuzzification). the most commonly utilized mf is a bell-shaped or gaussian function. journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 299 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. layer 2 layer 3 layer 4 w2 w1 input1: x 𝐵2 𝐴1 𝐴2 𝐵1 𝜋 𝜋 n n input2: y f x y x y w̅1 w̅2 layer1 layer 5 layer2 : each node of this layer, discriminated as п, performs the intersection of the input signals, simulates a logical and operation, and sends a value to the output: wi=μai(x).μbi(y) ; i = 1,2 (28) essentially, every node specifies an activating rule force wi. in actuality, any operator of t-norm, which summarizes the and operation can be utilized in these nodes. layer3: every node in this layer determines the weight of the normalized rules. w̅i= wi w1+w2 ; i = 1,2 (29) layer4: in this layer, nodes produce the output variables values: oi 4= w̅ifi= w̅i(aix + biy+ ri) (30) layer 5. in this layer is obtained the neural network output and carried out the defuzzification: oi 5=overall output =∑ w̅ifi= ∑ wifii ∑ wii i (31) figure 5 input mf and outputs of proposed anfis controller 6. simulation and result simulink implementation of the dtc-svm for im drive is shown in fig. 6, it was carried out using matlab/simulink software. the speed reference and stator flux reference value are 350 rad/sec and 0.476 wb. respectively. the motor is unloaded at startup and the torque load (tl) 8 nm is applied at t 2s. the switching frequency of svm is 10 khz, while the paramters of im are used in this paper as shown in table-1. the results of simulation show the comparison between the conventional pi controller (trial and error), stfpi controller and anfis based on dtc-svm of im drive. the simulink model of dtc-svm for im drive in fig. 6 is replacing all pi controllers by stfpi controllers. three stfpi controllers are observing the pattern of the errors for speed , flux and the torque and correspondingly updates the outputs kp and ki .the structure of stfpi controller for speed, torque and flux is the same and shown in fig. 7. matlab/fuzzy logic toolbox is employed to simulate mf of flc is choosing the triangular shape and no. of mfs are five for inputs and outputs as shown in fig. 8, while the value of kpf and kif are calculated from a fuzzy rule base defined in function of the control ( e and de/dt) as shown in the table-2. the centroid defuzzification method is employed here. the simulink model of dtc-svm for im drive in fig. 6 is replacing all pi controllers by anfis controllers to achieve precision speed control. the anfis controller produces one output such as the reference torque (te ∗ ), vds or vqs based on (e and de/dt) for speed, torque and flux respectively. the anfis designed through the anfis editor, the grid partition is utilized to produce fis when the hybrid method is used for optimization. in anfis controller utilized 25 if –then rules, gaussian mf type and the number of training epochs are used 2000 epochs. result anfis turning is shown in fig. 9. while fig. 10 and fig. 11 show that input mfs and anfis model structure respectively. figure 12 to fig. 15 show the response of speed and torque at various loaded when using conventional pi controller (trial and error), while fig. 16 to fig. 19 illustrate the simulation results journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 300 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. of speed and torque under same load variation. the simulation results of the speed and torque at various load using anfis are given in fig. 20 to fig. 23. the results of simulation show that the anfis controller realizes a good response of motor speed to sudden changes without overshoot, a fast settling time, the settling time is 0.166 s while the settling time for stfpi controller and conventional pi controller are 0.33s and 0.46s respectively, less steady state error, less ripple in torque response and improved the performance of motor when compared with both pi and stfpi controllers. figure 6 the simulink model of the dtc_svm for im drive table-1 parameters of im parameter value the power rating of im 3 hp voltage applied 220 v frequency 60 hz no of poles(p) 4 stator resistance(rs) 0.435  rotor resistance(rr) 0.816  stator leakage inductance(lls) 0.002 h rotor leakage inductance(llr) 0.002 h mutual inductance (lm) 0.0693 h inertia moment (j) 0.089kg.m2 0.476 journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 301 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 7 the simulink model of stfpi controller figure 8 inputs and output of mf for flc table-2.the rule base of kpand ki error kp,ki nb ns z ps pb nb s,s s,s m,s m,m b,m ns s,s m,s m,m b,b vb,vb z m,s m,m b,b vb,vb vb,vvb ps m,m b,b vb,vb vb,vvb vvb,vvb pb b,b vb,vb vb,vbb vvb,vbb vvb,vbb c h a n g e o f e rr o r journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 302 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 9 result anfis turning figure 10 inputs mf and outputs of proposed anfis controller figure 11 anfis model structure journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 303 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 x: 0.46 y: 350 time (sec) s p e e d ( r a d /s e c ) wref wr 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 -200 -150 -100 -50 0 50 100 150 200 time (sec) t o r q u e ( n .m ) 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 time (sec) s p e e d ( r a d /s e c ) 2 2.5 3 3.5 4 4.5 5 340 345 350 355 load 8 n,m figure 12 the speed response for used conventional pi controller at no-load figure 13 the torque response for used conventional pi controller at no-load figure 14 the speed response for used conventional pi controller with tl=8 nm at t 2s journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 304 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 -150 -100 -50 0 50 100 150 200 time (sec) t o r q u e ( n .m ) 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 x: 0.33 y: 350 time (sec) s p e e d ( r a d /s e c ) wref wr 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 -200 -150 -100 -50 0 50 100 150 200 time (sec) t o r q u e ( n .m ) figure 15 the torque response for used conventional pi controller with tl=8 nm at t 2s figure 16 the speed response for used stfpi controller at no-load figure 17 the torque response for used stfpi pi controller at no-load journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 305 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 time (sec) s p e e d ( ra d /s e c ) 2 2.5 3 3.5 4 345 350 355 load 8 n.m 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 -200 -150 -100 -50 0 50 100 150 200 time (sec) t o r q u e ( n .m ) 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 x: 0.166 y: 350 time (sec) s p e e d ( ra d /s e c ) wref wr figure 18 the speed response for used stfpi controller with tl=8 nm at t 2s figure 19 the torque response for used stfpi controller with tl=8 nm at t 2s figure 20 the speed response for used anfis at no-load journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 306 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 time (sec) s p e e d ( ra d / se c ) 2 2.5 3 3.5 4 345 350 355 load 8 n.m 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 -200 -150 -100 -50 0 50 100 150 200 time (sec) t o rq u e ( n .m ) 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 -200 -150 -100 -50 0 50 100 150 200 time (sec) t o rq u e (n .m ) figure 21 the torque response for used anfis at no-load figure 22 the speed response for used anfis controller with tl=8 nm at t 2s figure 23 the torque response for used anfis controller with tl=8 nm at t 2s journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 307 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. conclusion in this paper, the proposed anfis based dtc-svm for speed control of im drive and compared the results of the simulation with the conventional pi controller (trial and error) and stfpi controller. stfpi controller is employed for adjusted the parameters of pi controller to guarantee the stability of system over the wide speed range.with results obtained from simulation, it is clear that for the same operation condition of induction motor, stfpi controller has better performance than the conventional picontroller. by comparing. anfis controllers with stfpi controller ,it has been better performance, smaller settling time, less ripples of torque and more robust for sudden changes in load. references 1-hanumanji kantari, "direct torque control of induction motor using space vector modulation (svm dtc)". 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"application of fuzzy neural network in the speed control system of induction motor", computer science and automation engineering (csae), ieee international conference on. ieee, vol.3, pp.673-677, 2011. 12-arun shankar v.k, umashankar s, sanjeevikumar p,and paramasivam s, "adaptive neuro-fuzzy inference system (anfis) based direct torque control of pmsm driven centrifugal pump" international journal of renewable energy research,vol.7, no.3, 2017. 13fayez g. areed, amira y. haikal and reham h. mohammed, "adaptive neuro fuzzy control of an induction motor", ain shams engineering journal, ,vol 1, no.1, pp.71-78, (2010). http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.ahmed%20j.%20fattah.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.ikhlas%20abdel-qader.qt.&newsearch=true http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=7274378 http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=7274378 http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.ahmed%20j.%20fattah.qt.&newsearch=true journal of al-qadisiyah for engineering science vol. 11, no.3 issn: 1998-4456 page 308 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 14arun kumar r and febin daya j l,"a novel self-tuning fuzzy based pid controller for speed control of induction motor drive", in control communication and computing (iccc), 2013 international conference on, ieee, pp. 62-67, (2013). 15 a.durga bhavani, mrs. g. durga devi and dr.k.satyanarayana," an improved speed and torque performance of anfis based direct torque controlled induction motor drive", international journal of scientific & engineering research, volume 6, issue 12,2015. 16-tripti rai and prashant debre, "generalized modeling model of three phase induction motor", international conference on energy efficient technologies for sustainability (iceets). ieee, pp. 927-931, 2016. 17-manoj datta; md. abdur rafiq and b. c. ghosh, "genetic algorithm based fast speed response induction motor drive without speed encoder". international conference on power engineering, energy and electrical ieee, pp.146-151, 2007. 18-hongxia yu and zhicheng chen, "three-phase induction motor dtc-svpwm scheme with self-tuning pi-type fuzzy controller" international journal of computer and communication engineering, vol.4, no.3, 2015. 19-naveen goel; saji chacko and r. n. patel, "performance enhancement of direct torque control im drive using genetic algorithm". annual ieee india conference (indicon). ieee, pp. 1-6, 2015. 20-abolfazl ranjbar noei and hedyeh agheh kholerdi, "practical intelligent modeling of three-phase induction machine". information and knowledge technology (ikt), 7th conference on. ieee, pp.1-6, 2015. 21-ayushi pg, "speed control of induction motor using fuzzy logic controller", international journal of advanced research in electrical, electronics and instrumentation engineering, vol. 4, issue 4, 2015. 22-boussada, z., hamed, m. b., and sbita, l. " adaptive neuro-fuzzy inference system into induction motor: estimation". electrical sciences and technologies in maghreb (cistem), international conference on , ieee, pp. 1-5, 2014. 23-sujatha, k. n., and vaisakh, k. ,"implementation of adaptive neuro fuzzy inference system in speed control of induction motor drives". journal of intelligent learning systems and applications, vol.2, no. 2, pp.110-118, 2010. 24-mohamed mahmoud. ismail, "speed sensor less observer using lyapnov design and anfis for dtc of magnetically saturated induction motor", computer engineering conference (icenco), seventh international, ieee, pp.62-71, 2011. 25-zgurovsky, m. z., and zaychenko, y. p,"the fundamentals of computational intelligence: system approach", springer, vol. 652, pp. 1-371, 2017. http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.tripti%20rai.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.prashant%20debre.qt.&newsearch=true http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=7578986 http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=7578986 http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.manoj%20datta.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.md.%20abdur%20rafiq.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.b.%20c.%20ghosh.qt.&newsearch=true http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=4380079 http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.naveen%20goel.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.saji%20chacko.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.r.%20n.%20patel.qt.&newsearch=true http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=7438527 article al-qadisiyah journal for engineering sciences 12 (2019) 072–078 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohamed.aldawody@qu.edu.iq (mohamed f. al-dawody) https://doi.org/10.30772/qjes.v12i2.587 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. numerical simulation for the effect of biodiesel addition on the combustion, performance and emissions parameters of single cylinder diesel engine mohammed s. edama and mohamed f. al-dawodya* a department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq. a r t i c l e i n f o article history: received 07 may 2019 received in revised form 18 june 2019 accepted 29 june 2019 keywords: castor methyl ester diesel engine diesel-rk software engine performance emission a b s t r a c t this work examines the characteristics of combustion, performance and emissions of single cylinder diesel engine powered by diesel fuel and a different volume percentages of the caster methyl ester (cme). the selected biodiesel is studied numerically using the simulation program diesel-rk. the results reported that peak pressure is closer to the top dead center (tdc), as the percentage of cme. the brake specific fuel consumption (bsfc) is increased slightly as the blending of biodiesel is increased. all the selected biodiesel ratios are found to release higher nox emission compared to diesel. dramatic reduction in smoke levels 15.25 %, 35.3 %, 40.7 %, 45.71 %, 49.43 %, and 52.73 % with b10% cme, b20% cme, b30% cme, b50% cme, b70% cme and b100% cme respectively. b20% cme biodiesel was the best remarked ratio which gives slight variations in performance with a good reduction in the carbon emissions compared to diesel fuel. the results are compared with other researchers work and nice convergence is observed. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction vegetable oil has been a competitive alternative to diesel since 1900, gaining considerable attention during the second world war because of the lack of fuel at that time and the difficulty of obtaining it. after world war, the world turned to fossil fuel production, which was found affordable because of low production cost. however, after oil production was controlled by opec's, the problem of environmental pollution was greatly exacerbated and people's lives were threatened with great risks. it becomes necessary to find an alternative fuel. access to oil from plant resources has attracted considerable attention. in many countries, vegetable oils are used after esterification as "biodiesel". biodiesel has evolved to be one of the most widely used biofuels for the partial replacement of petroleum based diesel, especially in recent years. vegetable oils are most commonly used for biodiesel production [1]. biodiesel is a sustainable energy source to meet the growing global demand for transportation energy and significantly reduce greenhouse gas emissions. non-edible vegetable oils are a highly suitable candidate for production of biodiesel where they can be grown in marginal and harsh lands requiring less soil fertility, less maintenance and less water than arable land for edible plant oils [2]. bio-fuels, particularly castor oil and castor methyl ester, might help a lot to meet the future energy supply demands as well as contributing to the reduction of greenhouse gases emissions and other harmful products of the combustion process[3]. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i mohammed edam and mohamed al-dawody /al-qadisiyah journal for engineering sciences 12 (2019) 0072–078 73 nomenclature ao, a2,a3 constants. pm particulate matter b10 volume blend contains 90 % diesel plus 10 % cme r constant of gas (universal) b20 volume blend contains 80 % diesel plus 20 % cme cme castor methyl ester b30 volume blend contains 70 % diesel plus 30 % cme rpm revolutions / minute b50 volume blend contains 50 % diesel plus 50 % cme rps revolutions /second b70 volume blend contains 30 % diesel plus 70 % cme t temperature in the cylinder b100 volume blend contains 100 % cme t time bsfc brake specific fuel consumption (kg/kw.h) tdc top dead centre df diesel fuel u instantaneous fuel velocity bsn bosch smoke number u0 spray initial velocity [c] cylinder concentration soot um the velocity of the spray’s front oc degrees centigrade v the cylindrical volume oca crank angle degrees x heat release proportion cn cetane number of fuel xo the fraction of the fuel vapour forming in the delay period. ea the apparent activation energy for the auto ignition process kt constant of evaporation greek symbols l spray length σ cylinder fuel fractions lm penetration distance σu vapor fraction mf fuel mass τ delay period (second) nox nitrogen oxides θ crank angles (degree) p cylinder pressure (pa) 𝜙 equivalence ratio ps fuel saturation vapour pressure  exhaust gas exponent one of the most attractive features of biodiesel is its biodegradability and being more environmentally friendly than fossil fuels, resulting in less environmental impact when it releases harmful emissions. where emissions such as total hydrocarbons and carbon monoxide were observed to be significantly lower with biodiesel than diesel fuel [1]. in addition, it contains about 10–15% oxygen by weight [2]. after the production of biofuels in the world has grown widely, some criteria have to be put in place to ensure the quality of production, including the specifications of the american standard of testing materials (astm) and european union (eu) specifications. hence, researchers began to research the possibility of using biodiesel in diesel engines [3]. the researchers have been also using biodiesel as a renewable source to investigate the characteristics of emission, performance as well as combustion parameters. lin et al. [4], studied diesel oil and 8 kinds of biodiesel in ci engine. experimental results showed, an increase in bsfc, decreased engine performance slightly and decreased smoke emissions, which is due to the uniform mixing of air and fuel and the strengthening of oxygen due to using a vegetable oil methyl ester. the nitrogen oxides emission is increased as the temperature of combustion is increased total hydrocarbon emission (thc) are decreased because of many factors such as uniform mixing of fuel-air, higher oxygen quantity and due to longer spray penetrations as well. r. sattanathan [5] investigated the production of biodiesel (castor methyl ester) (cme)) from castor oil with its performance and emission testing, and the study focused on testing the engine using a mixture of cme. the fuel mixture b25, b50, b75, and b100 is prepared and fed in the 4 strokes, one cylinder, direct injection engine, water cooled with a compression ratio of 17.5: 1. results of author’s experiments indicate, the brake power of cme was almost similar for the diesel engine, while the specified fuel consumption was higher than diesel. also, the emission of hydrocarbons and smoke for cme is less than diesel emissions. s. lee et al. [6] studied the effects of the karanja oil methyl ester (kome) blending ratio on spray properties, engine performance analysis and exhaust emissions from the karanja biodiesel mix. in the engine experience, lower torque, brake thermal efficiency (bte) and exhaust gas temperature were observed, as well as higher fuel consumption for the biodiesel mix compared to diesel because of the lower heating value of the karanja biodiesel. the research work is aimed to study the use of various cme biodiesel blending ratios on combustion, and parameters of emissions and performance of single cylinder diesel engine using diesel-rk simulation program. 2. biodiesel properties the physical properties of the prepared biodiesel along with diesel fuel are measured accurately at aldora refinery factor according to the table reported below. table 1. displays the characteristics of a different mix of df and cme biodiesel. the numerical analysis was performed on a direct injection diesel engine and water cooled using a single cylinder. the engine specifications are displayed in table 2. table (1). diesel and cme blends properties property density at 15oc (kg/m3) viscosity at 40oc (pa.s) calorific value (mj/kg) surface tension (n/m) cetane number diesel 830 0.002241 45.836 0.028 53.4 b10% cme 837 0.003068 45.686 0.02953 53.06 b20% cme 845.2 0.003925 45.556 0.03106 52.9 b30% cme 851 0.004724 45.386 0.03259 52.38 b50% cme 865 0.00638 45.086 0.03565 51.7 b70% cme 879 0.008036 44.786 0.03871 51.02 cme 900 0.01052 44.336 0.0433 50 table (2) engine dimensions[7] engine brand kirloskar taf-1 type of engine 4-stroke, diesel engine, single cylinder bore stroke 80 mm 110 mm the cylinder capacity 0.553 l the compression ratio 15.5 rated power 3.7 kw , 1500 rpm orifice diameter 0.15 mm injection pressure 220 bar 74 mohammed edam and mohamed al-dawody/al-qadisiyah journal for engineering sciences 12 (2019) 072–078 3. numerical simulation approach the multizone combustion model has been used in this work. the fuel distribution is sprayed with 2 stages: free jet & wall jet as illustrated in fig. 1. there are a specific condition of evaporation and combustion for each zone identified in the model. 1. free wall (before impingement) the conical nucleus of free spray. front dense spray free. the diluted outer shell of the spray. 2. after wall impingement another 4 zones are formed: the near-wall flow (nwf) nucleus the nwf is dense on the surface of the piston. front dense of the nwf. nwf extensible out zone. figure 1. diesel spray zones (m. f. al-dawody, [8]) the current speed and location of the elementary fuel mass (efm) from the injector to the tip of the spray is given by to [9]: [𝑈 𝑈°⁄ ]^(3 ⁄ 2) = 1 − 𝑙/𝑙𝑚 (1) fig. 2. presents the variation of spray evolution parameters as functions of time. the governing evaporating details are described in [8]. figure 2. spray development v/s time [8]. 3.1. heat release model the fuel combustion is normally divided into four phases, which have separate chemical and physical properties that restricted combustion speed. a. delay period. the period of delay is estimated from the equation of tolstov [10]: 𝜏 = 3.8 ∗ 〖10〗^(−6). 𝑛√(𝑇/𝑃) ∙ 𝑒𝑥𝑝(𝐸𝑎/8.312𝑇 − 70/(𝐶𝑁 + 25)) (2) b. the phase of uncontrolled combustion (premixed) [11] 𝑑𝑥/𝑑𝜏 = 𝜑° [𝐴° (𝑚𝑓 /𝑉𝑖 )(𝜎𝑢𝑑 − 𝑥° )(0.1𝜎𝑢𝑑 + 𝑥° )] + 𝜑1 (𝑑𝜎𝑢/𝑑𝜏) (3) cdiffusion phase.[11] 𝑑𝑥/𝑑𝑡 = 𝜑1 (𝑑𝜎𝑢/𝑑𝜏) + 𝜑2 (𝐴2 (𝑚𝑓 𝑉⁄ )(𝜎𝑢 − 𝑥)(∅ − 𝑥) (4) dcombustion tail [12] 𝑑𝑥/𝑑𝜏 = 𝜑3 𝐴3 𝐾𝑇 (1 − 𝑥)(𝜀𝑏 ∅ − 𝑥) (5) during the process of simulations, woschni’ s formula has used to predict coefficients of heat transfer in the cylinder[13]. 3.2. the nitrogen oxides model the nitrogen oxide reaction is[12]: 𝑁 + 𝑂2 ↔ 𝑁𝑂 + 𝑂 (6) t the reaction is depended on the oxygen concentration. the volumetric of no concentration is given by: (7) 3.3. the soot concentration model soot particle forms grow and oxidizes due to chemical reaction occurring through combustion. it has a deep impact on the pollution of the environment the concentration of soot particle is calculated[8]: [𝐶] = ∫ 𝑑[𝐶] 𝑑𝜏 480 𝜃𝐵 𝑑𝜃 6𝑛 [ 0.1 𝑃 ] 𝛾 (8) the bosch smoke number (bsn) was obtained from hartidge smoke equation given below[14]: 𝐻𝑎𝑟𝑡𝑖𝑑𝑔𝑒 = 100[1 − 0.9545 ∗ 𝑒(−24226[𝐶])] (9) the pm emissions (are obtained from[14]: [𝑃𝑀] = 565 [ln 10 10−𝐵𝑜𝑠𝑐ℎ ] 1.206 (10) 3.4. basic equations of performance[15].: a. brake thermal efficiency (bte) using equation (11) to calculate the brake thermal efficiency bte = bp ṁf ∗ lcv⁄ (11) where: lcvlower heating value of blended fuel (kj/kg) b. brake specific fuel consumption the brake specific fuel consumption (bsfc) is calculated by using the equation (12). bsfc = (ṁf bp)⁄ ∗ 3600 (12) where: ṁf = fuel consumption rate 4. results and discussion the range of operating conditions were constant engine speed 1500 rpm, injection pressure 220 bars and 20o btdc injection timing. the condition of full load is selected as it gives maximum smoke as well as minimum air/fuel ratio. this gives the right situations to confirm any differences among the fuel blends under study.                                     rps onoetrt nonoonep d nod e t zz eee t z z 1 . /../23651 /1.10*33.2 2 3365 2 2 38020 7  mohammed edam and mohamed al-dawody /al-qadisiyah journal for engineering sciences 12 (2019) 072–078 75 4.1. combustion parameters fig.3 presents the variation of pressure verse crank shaft angle for df and biodiesel blends at full load. it is found that pmax is 73.4436 bars for df at 369 crank angle while it comes nearer to tdc for b100 cme where the maximum pressure was 80.2889 bars at 366o crank angle. the pressure of 10% and 20 % cme are noticed closer to that of df figure 3. variation of cylinder pressure with crank angle the predicted zonal temperature is described in fig. 4. the higher combustion temperatures for cme mixtures are reported. the high flame temperature is an indicator of the high nox emissions. the maximum temperature difference between 20% cme and df is 49 k at 362ᵒ crank angle. it's the direct cause of the high nox emission of biodiesel. the same observations were noted in the results of [16]. figure 4. variation of zonal temperature with crank angle figs. 5 and 6 present the computed heat release rate and the fraction of heat release for df and cme biodiesel respectively. the heat release fraction can be defined as the ratio of heat release rate to the lower heat value of the fuel. all cme blends have an earlier start of combustion but lower combustion rates. in the diffusion phase, most fuel has been vaporizing and burning as well, because of the rapid combustion of cme biodiesel. figure 5. show the heat release rate vs. crank angle. figure 6. show the heat release fraction vs. crank angle fig. 7. shows the effect of cme ratio on the delay period. fuel ignition quality is affected by auto ignition. the shorter delay period comes as a result of the difference in cetane number the combustion starts too early, and reduction in the heat released is expected. the same findings are confirmed by [17]. figure 7. effect of cme blending on ignition delay 150 200 250 300 350 400 450 500 550 crank angle (deg.) 0 10 20 30 40 50 60 70 80 90 100 c y li n d e r p re s s u re ( b a r) simulation results full load 1500 rpm diesel 10 % cme 20% cme 30 % cme 50% cme 70% cme cme 340 350 360 370 380 390 400 410 420 crank angle (deg.) 500 1000 1500 2000 2500 3000 z o n a l c o m b u s ti o n t e m p e ra u re ( k ) 340 350 360 370 380 390 400 410 420 crank angle (deg.) 0 10 20 30 40 50 60 h e a t re le a s e r a te ( j /d e g .) 340 350 360 370 380 390 400 410 420 crank angle (deg.) 0.00 0.20 0.40 0.60 0.80 1.00 h e a t re le a s e f ra c io n ( % ) 0 20 40 60 80 100 cme (%) 2 4 6 8 10 d e la y p e ri o d ( d e g .) simulation results full load, 1500 rpm 76 mohammed edam and mohamed al-dawody/al-qadisiyah journal for engineering sciences 12 (2019) 072–078 4.2. performance parameters fig. 8 shows the effect of cme blending on bsfc. bsfc was found to increase with the increase in cme ratio in fuel. to obtain the same torque and output power for each tested fuel, bsfc was higher for cme and its mixtures. bsfc for the b20%cme is higher than the df by 4.85%, while it is 7.39% higher for the cme b100. the higher level of density and lower heating energy are responsible for the increase in bsfc. these results are similar to those of [18] and [19]. figure 8. the variation of bsfc with cme biodiesel blends fig. 9. shows bte variation with cme ratios. it was observed that the bte of the cme mixtures were less than the df. the efficiency is slightly reduced as a result of increasing cme percentages because of lower calorific value of biofuel over that of ordinary diesel fuel. figure 9. the bte vs. cme blends. 4.3. emission parameters fig. 10. describes the effect of cme blends on the smoke quantity (bsn). the smoke level for all cme blends is lower than that of the df. the numerical findings reported a promising reduction in soot emissions by 15.25 %, 35.3 %, 40.7%, 45.6%, 49.43% and 52.7 % for b10, b20, b30, b50, b70 and b100 respectively. this due to a higher quantity of oxygen exist in biodiesel which has deep impact on oxidation of fuel, hence the tendency to produce smoke is greatly reduced [20]. figure 10. the bsn vs. cme blends fig. 11. explains the relation between the nox emissions with different percentages of cme blend. the emission of nox is higher for all cme blends as compared to diesel fuel. this is because of higher oxygen quantity in the biofuel. the higher cylinder pressure, as well as combustion temperature caused by early start of combustion, are the main reasons for increasing nox emission. the message in fig. 10 as well as fig. 11. says that b20% cme was the best compromise blending ratio, where 20% gives a good reduction in bsn but a sharp increase in nox emissions is reported hence the b20% cme is the best promising ratio chosen in this study. figure 11. the relation between nox emissions with cme biodiesel blends. 5. results verification in this section, the point of discussion is to compare some of the results obtained from an experimental investigation of other researchers[17, 21, 22] at the same conditions of the present study with the numerical results 0 20 40 60 80 100 cme (%) 0.38 0.40 0.42 0.44 b s f c ( k g /k w .h ) simulation results full load 1500 rpm bsfc vs cme % 0 20 40 60 80 100 cme (%) 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 b s n simulation results full load 1500 rpm 0 20 40 60 80 100 cme (%) 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 n o x ( p p m ) full load, 1500 rpm simulation results 0 20 40 60 80 100 cme (%) 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 b t e ( % ) simulation results full load 1500 rpm bte vs cme mohammed edam and mohamed al-dawody /al-qadisiyah journal for engineering sciences 12 (2019) 072–078 77 of diesel-rk software. from figs. 12 and 13 a slight difference between the two is recorded which indicate accepted reasonable accuracy of the present work. figure 12. verification of the spray tip penetration between different researchers. figure 13. verification of the cylinder pressure between different researchers 6. conclusions  cme blends are found to shift maximum pressure closer to the tdc.  the substitution of cme blending make an early combustion atarting as compared with df due to the shorter delay period.  the cme ratio was observed to increase bsfc as well as decrease brake thermal efficiency slightly.  promising reduction in bsn with all cme mixtures as compared to df.  it was observed that all cme mixtures emit higher nox emissions compared to df.  best mixing percentage is 20% cme that reports lower emissions compared to pure diesel and promising results of performance is noticed as well. references [1] m. siddiqur rahman, m. hossain, m. nawsher ali moral, production of biodiesel fuels from castor oil using h2so4 as catalyst, 2016. [2] m.f. al_dawody, s. bhatti, experimental and computational investigations for combustion, performance and emission parameters of a diesel engine fueled with soybean biodiesel-diesel blends, energy procedia, 52 (2014) 421-430. [3] g. knothe, j. krahl, j. van gerpen, the biodiesel handbook, elsevier, 2015. [4] b.-f. lin, j.-h. huang, d.-y. huang, experimental study of the effects of vegetable oil methyl ester on di diesel engine performance characteristics and pollutant emissions, fuel, 88(9) (2009) 1779-1785. [5] r. sattanathan, production of biodiesel from castor oil with its performance and emission test, int j sci res, 4(1) (2015) 273-279. [6] s. lee, c.s. lee, s. park, j.g. gupta, r.k. maurya, a.k. agarwal, spray characteristics, engine performance and emissions analysis for karanja biodiesel and its blends, energy, 119 (2017) 138-151. [7] m.f. al-dawody, a.a. jazie, h. abdulkadhim abbas, experimental and simulation study for the effect of waste cooking oil methyl ester blended with diesel fuel on the performance and emissions of diesel engine, alexandria engineering journal, 58(1) (2019) 9-17. [8] m.f. al-dawody, theoretical study for the influence of biodiesel addition on the combustion, performance and emissions parameters of single cylinder diesel engine, journal of university of babylon, 25(5) (2017) 1830-1839. [9] a. kuleshov, model for predicting air-fuel mixing, combustion and emissions in di diesel engines over whole operating range, 0148-7191, sae technical paper, 2005. [10] a. kuleshov, use of multi-zone di diesel spray combustion model for simulation and optimization of performance and emissions of engines with multiple injection, 0148-7191, sae technical paper, 2006. [11] m.f. al-dawody, s. bhatti, optimization strategies to reduce the biodiesel nox effect in diesel engine with experimental verification, energy conversion and management, 68 (2013) 96-104. [12] a. kuleshov, multi-zone di diesel spray combustion model and its application for matching the injector design with piston bowl shape, 0148-7191, sae technical paper, 2007. [13] g. woschni, a universally applicable equation for the instantaneous heat transfer coefficient in the internal combustion engine, sae transactions, (1968) 30653083. [14] a.c. alkidas, relationships between smoke measurements and particulate measurements, 0148-7191, sae technical paper, 1984. [15] a. datta, b.k. mandal, engine performance, combustion and emission characteristics of a compression ignition engine operating on different biodieselalcohol blends, energy, 125 (2017) 470-483. [16] w. yuan, a. c. hansen, z. tan, modeling of nox emissions of biodiesel fuels, in, asae, st. joseph, mi, 2005. [17] u. rajak, p. nashine, t.s. singh, t.n. verma, numerical investigation of performance, combustion and emission characteristics of various biofuels, energy conversion and management, 156 (2018) 235-252. [18] l. wei, r. cheng, h. mao, p. geng, y. zhang, k. you, combustion process and nox emissions of a marine auxiliary diesel engine fuelled with waste cooking oil biodiesel blends, energy, 144 (2018) 73-80. [19] r.s. kumbar, p.s. patil, o. hebbal, experimental investigation of performance and combustion characteristics on a single cylinder lhr engine using diesel and castor biodiesel, ijret: international journal of research in engineering and technology eissn, 340 350 360 370 380 crank angle (deg.) 0 20 40 60 80 100 s p ra y t ip p e n te ra ti o n ( m m ) results verfication present work dassari et al , 2017 prakash et al, 2018 rajak et al, 2018 200 300 400 500 600 crank angle (deg.) 0 20 40 60 80 100 c y li n d e r p re s s u re ( b a r) 78 mohammed edam and mohamed al-dawody/al-qadisiyah journal for engineering sciences 12 (2019) 072–078 2319-1163. [20] h. chen, j. he, h. hua, investigation on combustion and emission performance of a common rail diesel engine fueled with diesel/biodiesel/polyoxymethylene dimethyl ethers blends, energy & fuels, 31(11) (2017) 11710-11722. [21] t. prakash, v.e. geo, l.j. martin, b. nagalingam, effect of ternary blends of bio-ethanol, diesel and castor oil on performance, emission and combustion in a ci engine, renewable energy, 122 (2018) 301-309. [22] s.r. dasari, a.j. chaudhary, v.v. goud, n. sahoo, v. kulkarni, in-situ alkaline transesterification of castor seeds: optimization and engine performance, combustion and emission characteristics of blends, energy conversion and management, 142 (2017) 200-214. article al-qadisiyah journal for engineering sciences 12 (2019) 090–097 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: basilnoori679@gmail.com (basil n. merzah) https://doi.org/10.30772/qjes.v12i1.592 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. numerical study of flat plate solar collector performance with square shape wicked evaporator basil n. merzhaa*, majid h. majeedb, and fouad a. salehc apower department, al-furat al-awsat technical university, iraq b middle technical university, iraq c mechanical department, mustansiriyah university, iraq a r t i c l e i n f o article history: received 23 may 2019 received in revised form 18 june 2019 accepted 25 june 2019 keywords: wicked heat pipe flat plate solar collector radiation a b s t r a c t in this work, a system of a heat pipe is implemented to improve the performance of flat plate solar collector. the model is represented by square shape portion of the evaporator section of wicked heat pipe with a constant total length of 510 mm, and the evaporator section inclined by an angle of 30o. in this models the evaporator, adiabatic and condenser lengths are 140mm, 140mm, and 230mm respectively. the omitted energies from sunlight simulator are 200, 400, 600, 800 and 1000 w/m2 which is close to the normal solar energy in iraq. the working fluid for all models is water with fill charge ratio of 240%. the efficiency of the solar collector is investigated with three values of condenser inlet water temperatures, namely (12, 16 and 20o c). the numerical result showed an optimum volume flow rate of cooling water in condenser at which the efficiency of collector is a maximum. this optimum agree well with the ashrae standard volume of flow rate for conventional tasting for flat plate solar collector. when the radiation incident increases the thermal resistance of wicked heat pipe is decreases, where the heat transfer from the evaporator to condenser increases. the numerical results showed the performance of solar collector with square shape evaporator greater than other types of evaporator as a ratio 15 %. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction solar energy is considered one of the best sources of energy for many advantages. it is a huge source of potential energy, which can be obtained freely. it is also one of the permanent sources of energy which is inexhaustible and reliable because of its permanence and continuity. the fossil energy sources are causing pollution to the environment by the emission of carbon dioxide, as well as the problems of global warming, which is a serious problem now and the near future. heat pipes which are implemented still in its young stage of development and studies, more and deep investigations are required to integrate heat pipe in solar collector systems in order to improve the heat transport) the advantages of using the wicked heat pipe [1] long life because it has no moving parts and does not need the energy to power it in addition to the ability to work in minimum temperature difference. moreover, it does not require maintenance except cleaning plus the parts are very compact and flexible in size, very simple in design and the heat transfers in one way known (thermal diode), and small area demanded. some researchers have presented theoretical studies, including kamal a.r. ismail [2] manufactured and tested the flat plate solar collector (fpsc) with methanol as a working fluid heat pipe. the experimental results are compared with the numerical predictions and gave very good agreement. mahmood mustafa mahdy [3] was studied the effect of the adiabatic region for different three lengths of evaporator indoor for different incident radiation. the results were explained the best performance at a grope without adiabatic section. e. azad [4] was studied the effect the interconnected wick heat pipe on the solar collector. the result shown to enhance the performance of collector can be achieved by increasing the http://qu.edu.iq/ mailto:basilnoori679@gmail.com https://doi.org/10.30772/qjes.v12i basil n. merzha et. al /al-qadisiyah journal for engineering sciences 12 (2019) 090–097 91 number of heat pipes. k. sivakumar, et al [5] designed an elliptical shape of flat plate (hp) solar collector and presented results for various flow rates and lc/le ratios. majid h. majeed, et al [6] were studied the effect of the working fluid 134a on performance of heat pipe, the results showed when used the water as a working fluid have best performance when used r134a. taoufik brahim , et al [7] were studied the effect of the working fluids (water and methanol ) on the performance of solar collector with wicked heat pipe. the results showed good agreement between the two models, and also it was shown that the water is better than methanol where the collector instantaneous efficiency is nearly 60%. all the researchers did not analyze the square shape of the evaporator section and the numerical impact on the efficiency of the solar collector. 2. theoretical analysis the simple flat plate solar collector consists of a flat plate and the heat pipe sit in this plate that sealed and evacuated pipe lined with an annular porous wicking material and a small amount of working fluid in liquid state filled the wick. the vapor of working fluid flow in center core of the pipe. the glass cover placed upon it. fig.1. shows the principle of possible thermal loss of a typical flat plate collector. the common methods of heat loss are infrared radiation exchanges, convection heat loss and conduction through the insulations. figure (1): single-cover typical flat plate solar collector for glass cover: the balance of energy (w/m2) per a unit area of the collector is denoted as shown in fig. 2: figure (2): energy balance in the glass of solar collector 𝐸𝑖𝑛 𝑔𝑙𝑎𝑠𝑠 = 𝐸𝑜𝑢𝑡 𝑔𝑙𝑎𝑠𝑠 𝜌𝑔𝛿𝑔𝐶𝑔 𝑑𝑇𝑔 𝑑𝑡 = 𝛼𝑔 𝐺 + 𝑈 𝑝−𝑔(𝑇𝑝 − 𝑇𝑔 ) − ℎ𝑐,𝑔−𝑎 (𝑇𝑔 − 𝑇𝑎 ) − ℎ𝑟,𝑔−𝑎 ( 𝑇𝑔 − 𝑇𝑎 ) (1) for steady state 𝛼𝑔 𝐺 + 𝑈 𝑝−𝑔(𝑇𝑝 − 𝑇𝑔) − ℎ𝑐,𝑔−𝑎 (𝑇𝑔 − 𝑇𝑎 ) − ℎ𝑟,𝑔−𝑎 ( 𝑇𝑔 − 𝑇𝑎 ) = 0 (2) from duffie and beckman ∴ ℎ𝑟,𝑔−𝑎 = 𝜎 𝑔(𝑇𝑔 + 𝑇𝑎 )(𝑇𝑔 2 + 𝑇𝑎 2) (3) the external radiation heat transfer coefficient between the glass and ambient depended on wind velocity (𝑣𝑤 ) can calculate from [8] for 0 ≤ 𝑣𝑤 < 10: ℎ𝑐,𝑔−𝑎 = 5.7 + 3.8 𝑣𝑤𝑖 (4) 𝑈 𝑝−𝑔 = 1 1 ℎ𝑟,𝑝−𝑔 + 1 ℎ𝑐,𝑝−𝑔 (5) the radiation coefficient from the plate to glass is: ℎ𝑟,𝑝−𝑔 = 𝜎 (𝑇𝑝+𝑇𝑔)(𝑇𝑝 2+𝑇𝑔 2) 1 𝜀𝑝 + 1 𝜀𝑔 −1 (6) hollands et al. [9] give the equation for nusselt number for tilt angle from 0o to 75o. 𝑁𝑢𝑝−𝑔 = 1 + 1.44 [1 − 1708(sin 1.8𝜃)1.6 𝑅𝑎 𝑐𝑜𝑠𝜃 ] [1 − 1708 𝑅𝑎 𝑐𝑜𝑠𝜃 ] + [( 𝑅𝑎 𝑐𝑜𝑠𝜃 5830 ) 1 3⁄ − 1] (7) for flat plate: the balance of energy (w/m2) per unit area of the collector is denoted as: figure (3): energy balance in the flat plate of solar collector 𝐸𝑖𝑛 𝑓𝑙𝑎𝑡 𝑝𝑙𝑎𝑡𝑒 = 𝐸𝑜𝑢𝑡 𝑓𝑙𝑎𝑡 𝑝𝑙𝑎𝑡𝑒 𝜌𝑝 𝛿𝑝𝐶𝑝 𝑑𝑇𝑝 𝑑𝑡 = 𝛼𝑝 𝜏𝑔 𝐺 + 𝑘𝑝 𝛿𝑝 ( 𝜕2𝑇𝑝 𝜕𝑥2 ) − 𝑈 𝑝−𝑔(𝑇𝑝 − 𝑇𝑔) − 𝑈 𝑏 (𝑇𝑝 − 𝑇𝑎 ) (8) for steady-state 𝛼𝑝 𝜏𝑔 𝐺 + 𝑘𝑝 𝛿𝑝 ( 𝜕2𝑇𝑝 𝜕𝑥2 ) − 𝑈 𝑝−𝑔(𝑇𝑝 − 𝑇𝑔) − 𝑈 𝑏 (𝑇𝑝 − 𝑇𝑎 ) = 0 (9) duffie and beckman can calculate the bottom heat transfer coefficient: 𝑈 𝑏 = 𝐾𝑖𝑛 𝛿𝑖𝑛 (10) from boundary condition as shown in fig. 4. can be written: 𝑑𝑇𝑝 𝑑𝑋 = 0 𝑤ℎ𝑒𝑛 𝑥 = 0 𝑇𝑝 = 𝑇𝑒 𝑤ℎ𝑒𝑛 𝑥 = 𝑤 2 for evaporator section of the wicked heat pipe the balance of energy (w/m) is denoted as: 𝜌𝑒 𝐴𝑒 𝐶𝑒 𝑑𝑇𝑒 𝑑𝑡 = [𝜏𝑔𝛼𝑝]𝑒 𝐺 𝑑𝑜 2 + 𝑘𝑝 𝛿𝑝 𝜕𝑇𝑝 𝜕𝑥 − 𝜋𝑑𝑜 2 𝑈𝑒𝑔(𝑇𝑒 − 𝑇𝑔) − 𝜋𝑑𝑒𝑖 ℎ𝑒𝑖 (𝑇𝑒 − 𝑇𝑠 ) − 𝑘𝑒𝑓𝑓 𝐿𝑒 𝑇𝑒−𝑇𝑤 𝛿𝑤 (11) the heat transfer coefficient of the wicked evaporator is given by b.sivaraman [10] ℎ𝑒𝑖 = 3 4 [ 𝜌𝑙 2𝑘3𝑔ℎ𝑓𝑔 4 𝜇𝑙(𝑇𝑒− 𝑇𝑠)𝐿𝑒 ] 1 4 (12) the energy balance of the wick in the heat pipe (w/m3) is given: (𝜌𝐶)𝑒𝑓𝑓 [ 𝜕𝑇 𝜕𝑡 ] = 𝑘𝑒𝑓𝑓 [ 𝜕2𝑇 𝜕𝑥2 ] (13) single glass cover flat plate pipe wood frame collector frame isolation g ℎ𝑟,𝑔−𝑎 ℎ𝑐,𝑔−𝑎 𝑈𝑝−𝑔 𝑈𝑏 g𝜏𝑔 𝑈𝑝−𝑔 92 basil n. merzha et al. /al-qadisiyah journal for engineering sciences 12 (2019) ) 090–097 the effective thermal conductivity and heat capacity of wick structure, for screen wire mesh, are written as:[11, 12] 𝐾𝑒𝑓𝑓 = 𝐾𝑙 ∗ [(𝐾𝑙+𝐾𝑤)−((1− )∗(𝐾𝑙−𝐾𝑤))] [(𝐾𝑙+𝐾𝑤)+((1− )∗(𝐾𝑙−𝐾𝑤))] (14) where; 𝐾𝑒𝑓𝑓: effective thermal conductivity (𝜌𝐶)𝑒𝑓𝑓 = 𝜺(𝜌𝐶𝑝 )𝑙 + (1 − 𝜺)(𝜌𝐶)𝑤 𝑁𝑢𝑒−𝑔 = 1 + 1.44 [1 − 1708(sin 1.8𝜃)1.6 𝑅𝑎 𝑐𝑜𝑠𝜃 ] [1 − 1708 𝑅𝑎 𝑐𝑜𝑠𝜃 ] + [( 𝑅𝑎 𝑐𝑜𝑠𝜃 5830 ) 1 3⁄ − 1] (15) 𝑅𝑎𝑒−𝑔 = 𝑔 𝛽 (𝑇𝑒−𝑇𝑔) 𝑥 3 𝑣 𝛼 (16) ℎ𝑟,𝑒−𝑔 = 𝜎 (𝑇𝑒+𝑇𝑔)(𝑇𝑒 2+𝑇𝑔 2) 1 𝜀𝑒 + 1 𝜀𝑔 −1 (17) the energy balance (w) for working fluid (water) will be saturated liquid because the density for vapor phase compared to liquid phase is small. 𝜋𝑑𝑖 2 4 𝜌𝑙 𝜑𝐿𝑡 𝐶𝑙 𝑑𝑇𝑠 𝑑𝑡 = 𝜋𝑑𝑖 𝐿𝑒 ℎ𝑒 (𝑇𝑒 − 𝑇𝑠 ) − 𝜋𝑑𝑖 𝐿𝑐 ℎ𝑐 (𝑇𝑠 − 𝑇𝑐 ) (18) for steady-state 𝜋𝑑𝑖 𝐿𝑒 ℎ𝑒 (𝑇𝑒 − 𝑇𝑠 ) = 𝜋𝑑𝑖 𝐿𝑐 ℎ𝑐 (𝑇𝑠 − 𝑇𝑐 ) (19) in condenser section of the thermosyphon in flat plate solar collector, the heat-transfer coefficient of condensation film (ℎ𝑐) (w/m 2 k) may be calculated by the relation concluded by [13] as follows: ℎ𝑐 = [0.997 − 0.334(𝑐𝑜𝑠𝜃) 0.108] [ 𝑘𝑙 3𝜌𝑙 2𝑔ℎ𝑓𝑔 𝜇𝑙𝐿𝑐(𝑇𝑠− 𝑇𝑐) ] 0.25 [ 𝐿𝑐 𝑑𝑖 ] [0.254(𝑐𝑜𝑠𝜃)0.385] (20) for condenser section fig (4): the balance of energy (w/m) of the thermosyphon is represented as: 𝜌𝑐 𝐴𝑐 𝐶𝑐 𝑑𝑇𝑐 𝑑𝑡 = 𝑘𝑐 𝐴𝑐 𝜕2𝑇𝑐 𝜕𝑥2 + 𝜋 𝑑𝑣 ℎ𝑐 (𝑇𝑠 − 𝑇𝑐 ) + 𝐾𝑒𝑓𝑓𝐿𝑐 𝑇𝑤− 𝑇𝑐 𝛿𝑤 − 𝜋 𝑑𝑜 ℎ𝑐𝑖 (𝑇𝑐 − 𝑇𝑤 ) (21) the boundary conditions are: figure (4): the coordinate of the condenser section at 𝑥 = 0 → 𝑇𝑐 = 𝑇𝑠 at 𝑥 = 𝐿𝑐 → 𝑑𝑇𝑐 𝑑𝑥 = 0 the heat transfer coefficient of a wicked condenser is given by b.sivaraman[10] ℎ𝑐𝑖 = 3 4 [ 𝜌𝑙 2𝑘3𝑔ℎ𝑓𝑔 4 𝜇𝑙 (𝑇𝑒 − 𝑇𝑠 )𝐿𝑐 ] 1 4 the radiation incident energy absorbed by the absorber flat plate can be classified into useful energy and to energy losses. useful energy is the energy received from the condenser, but the lost energy has a great value that is through the top and less value by the sides, undermost and edges of the collector through the insulator. this energy loss can be calculate by heat transfer coefficient from top (ut) through glass, rear heat transfer coefficient (ub) through rear insulation and rim heat transfer coefficient (ue) through the rim insulation of the collector. thus the overall heat coefficient from the collector are calculated from [8] 𝑈𝑡𝑜𝑡 = 𝑈𝑡 + 𝑈𝑏 + 𝑈𝑒 to found losses from top, bergman, t.l give the relation[14] 𝑈𝑡 = 1 𝑁 𝐶 𝑇𝑝𝑚 [ 𝑇𝑝𝑚−𝑇𝑎 𝑁 + 𝑓 ] 𝑒 + 1 ℎ𝑤𝑖 + 𝜎(𝑇𝑝𝑚 + 𝑇𝑎 )(𝑇𝑝𝑚 2 + 𝑇𝑎 2) ( 𝑝 + 0.0059 𝑁ℎ𝑤𝑖 ) −1 + 2𝑁 + 𝑓 − 1 + 0.133 𝑝 𝑔 − 𝑁 𝑓 = (1 + 0.089ℎ𝑤 − 0.1166ℎ𝑤 𝑝)(1 + 0.07866𝑁) 𝐶 = 520(1 − 0.000051𝜃2) for 0 < 𝜃 < 70 𝑒 = 0.430(1 − 100 𝑇𝑝𝑚 ) ℎ𝑤 = 5.7 + 3.8 𝑣𝑤 𝑈𝑒 = (𝑈𝐴)𝑒 𝐴𝑐𝑜𝑙𝑙 𝑈𝑒 = 2𝑘𝑖𝑛 (𝑙𝑐𝑜𝑙𝑙+𝑤𝑐𝑜𝑙𝑙)𝐻𝑐𝑜𝑙𝑙 𝑙𝑐𝑜𝑙𝑙∗𝑤𝑐𝑜𝑙𝑙∗𝛿𝑖𝑛𝑒 𝜂 = ∫ 𝑄𝑢𝑑𝑡 𝐴𝑐𝑜𝑙𝑙 ∫ 𝐺𝑑𝑡 𝜂 = 𝑄𝑢 𝐺 𝐴𝑐𝑜𝑙𝑙 𝑄𝑢 𝐴𝑐𝑜𝑙𝑙 = 𝐺 𝛼𝜏 𝐶𝑜𝑠 𝜃𝑖 − 𝑈𝑡𝑜𝑡 ( 𝑇𝑓 − 𝑇𝑎𝑚𝑏 ) another expression 𝜂 = 𝑚𝐶𝑝 (𝑇𝑐𝑜− 𝑇𝑐𝑖 ) 𝐴𝑐𝑜𝑙𝑙 𝐺 computer simulations have become important in engineering sciences because they have wide options for simulation to improve or develop designs [15] comsol multiphysics is one of the programs that has an integrated environment to solve differential equations of one dimension or two dimensions as well as three dimensions and it possesses sophisticated simulation tools can be easily used [15]. the 3d model of the solar flat plate collector was carried out by comsol software version 5.3 where the geometry was used to drawing of comsol geometry as shown in fig. 5. for model no.1 and fig. 6. model no.2. for model no.1, the meshing using the normal size has consist of 4384091 domain elements, 359980 boundary elements, and 17576 edge elements, mesh on selected domains consists of 3663427 elements. minimum quality: 0.09402; average quality: 0.6663. as shown in fig. 7. for model no.1. for model no.2, the meshing using the normal size has consist of 2737951 domain elements, 459780 boundary elements, and 27775 edge elements, mesh on selected domains consists of 3663427 elements. minimum quality: 0.152; average quality: 0.684., and fig. 8. for model no. 2. x 1 2 basil n. merzha et. al /al-qadisiyah journal for engineering sciences 12 (2019) 090–097 93 figure (5): geometry model no.1 figure (6): geometry model no.2 figure (7): mesh of the geometry model no.1 for flat plate and evaporator section figure (8): mesh of the geometry model no.2 for flat plate and square shape evaporator section in this analysis one volume fraction concentrations (240%) [16] that effected on physical properties, with volume flow rate (3.75, 4.35 and 10l/h) with various inlet temperatures was introduced and the pressure outlet condition is carried at the exit. the thermophysical properties of the working fluid (distilled water) is variable with temperature input. impermeable boundary and no-slip wall conditions was performed on the channel walls. 3. results and discussion the effect of energy incident variation on wicked heat pipe behaviour was represented in fig. 9. it is noticed from the forms of the first and second models see figs. 10-13. when the incident radiation increases the flat plate temperature and evaporator section temperature increase too and the heat pipe transport more heat to condenser section then the temperature of condenser increases some degrees. this is due to increasing of the working fluid evaporation rate with increasing of the incident radiation, which the vapor velocity increases, this is due to increasing of the mass stream rate of evaporation for water and that with increasing of the incident radiation the liquid velocity will increase.figs. 14.-16 show the temperature contours for model that heat pipe with square shape evaporator. all these figures show the effect of variation of inlet water temperature on temperature distribution for pure water and the same incident radiation and same ambient temperature. in this figures show the models temperature contours, when the water temperature entering to the heat exchanger is increasing, the temperature off the condenser surface increases and the temperature off the flat plate and evaporator remains almost constant and will decrease the vapor velocity due to increasing the vapor density[17]. figs. 17.-19. show the temperature contours for model that wicked heat pipe with square shape evaporator. all these figures show the effect of variation of flow rate on temperature distribution for pure water and the same incident radiation and same ambient temperature. from the observation of this figures that the temperature of the condenser section were reduced with the raise of the volume flow rate of water with a slight increase in the temperature of evaporator section and flat plate because the increase in water flow rate will increase the process of heat transfer and thus condense a larger amount of water vapor. fig. 20. show the effect of flat plate temperature on the collector efficiency for a model that wicked heat pipe with square shape evaporator, for different ambient temperature each figure and different inlet water temperature. fig. 21. show the effect of flat plate temperature on the collector efficiency for a model that wicked heat pipe with square shape evaporator, for different ambient temperature each figure and different inlet water temperature. in the above figures, notice that when the plate temperature rise the collector efficiency is increasing for different ambient temperature and different inlet water temperature because the amount of water vapor is increasing and note that when the higher ambient temperature, the collector efficiency increases for this model because the heat transfer coefficient is less and thus less heat losses and thus causes increase in useful energy result that collector efficiency increases. figs. 22-23 show the effect of the factor [(tamb –twin)/g] on the performance of solar collector (sc) when the change stream rate of water. it could be evaluated that the performance of the collector by using a curve fitting method. the relationship represents as a first order, in figure the intersection efficiency curve with y-axis was represented 𝐹𝑅 (𝜏𝛼) whereas the tendency of the efficiency curve appears 𝐹𝑅 𝑈𝐿 hence, the performance of collector may be calculated from: 𝜂 = 𝐹𝑅 (𝜏𝛼) − 𝐹𝑅 𝑈𝐿 ( 𝑇𝑎𝑚𝑏 − 𝑇𝑤𝑖𝑛 𝐺 ) 94 basil n. merzha et al. /al-qadisiyah journal for engineering sciences 12 (2019) ) 090–097 table 1. for the model that wicked heat pipe with square shape evaporator was summarized the values of 𝑭𝑹(𝝉𝜶) and frul for the various water volume stream rates �̇�𝑤𝑖𝑛 (𝑘𝑔 𝑠⁄ ) 𝐹𝑅 (𝜏𝛼) 𝐹𝑅 𝑈𝐿 0.00104 0.2246 0.6114 0.0012 1.5332 0.6573 0.00278 2.2641 0.6484 as shown in fig. 22. and 1. the performance of collector is at a high value when a water volume stream rate of 4.35 kg/h. this water volume stream rate is extremely near to the ashrae norm for bloc stream average for examining fps heating collectors �̇�𝑤𝑖𝑛 = 0.0012 = 0.02 𝐴 [18] figure (9): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 200w/m2 and inlet water temperature 12oc and flow rate 57.3 l/h (area 0.06m2) (tamb= 27oc) figure (10): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 200w/m2 and inlet water temperature 12oc and flow rate 57.3 l/h (area 0.06m2) (tamb= 27 oc) figure (11): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 400w/m2 and inlet water temperature 12oc and flow rate 3.75 l/h (area 0.06m2) (tamb= 27oc) figure (12): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 600w/m2 and inlet water temperature 12oc and flow rate 57.3 l/h (area 0.06m2) (tamb= 27oc) figure (13): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 800w/m2 and inlet water temperature 12oc and flow rate 3.75 l/h (area 0.06m2) (tamb= 27oc) basil n. merzha et. al /al-qadisiyah journal for engineering sciences 12 (2019) 090–097 95 figure (14): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 200w/m2 and inlet water temperature 12oc and flow rate 5753 l/h (area 0.06m2) (tamb= 20oc) figure (15): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 200w/m2 and inlet water temperature 16oc and flow rate 5753 l/h (area 0.06m2) (tamb= 20oc) figure (16): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 200w/m2 and inlet water temperature 20oc and flow rate 5753 l/h (area 0.06m2) (tamb= 20oc) figure (17): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 400w/m2 and inlet water temperature 12oc and flow rate 3.75 l/h (area 0.06m2) (tamb= 27oc) figure (18): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 400w/m2 and inlet water temperature 12oc and flow rate 5753 l/h (area 0.06m2) (tamb= 27oc) figure (19): temperature distribution contour for flat plate collector with wicked heat pipe at energy input 400w/m2 and inlet water temperature 12oc and flow rate 01 l/h (area 0.06m2) (tamb= 27oc) 96 basil n. merzha et al. /al-qadisiyah journal for engineering sciences 12 (2019) ) 090–097 4. conclusion the flat plate solar collector with a wicked heat pipe that square shape evaporator was studied numerically. it is hoped that the information included in present study will help engineers to become more familiar with the various options available in the use of heat pipe in solar collector by for enhancing the efficiency of collector by using square shapes of evaporator. from the numerically woke the flowing can be concluded: 1the numerical tests were demonstrated the best volume flow rate of cooling water in condenser when �̇�𝑤𝑖𝑛 = 0.02 𝐴 at which the efficiency of collector is a greatest. this flow rate equal to 4.35 l/h for each numerical model. this optimum approves with the ashrae standard volume flow rate for exam the conventional solar water collectors. 2when the radiation incident increases the thermal resistance of wicked heat pipe that square shape evaporator decreases, where the heat transfer from the evaporator to condenser increases. 3the numerical result showed the performance of solar collector with square evaporator shape greater than conventional heat pipe solar collector as a ratio (15) %. references [1] b. zohuri, heat pipe design and technology, springer, 2011. [2] k.a.r.i.a.m.k. abogderah, residential solar collector with heat pipes, in, brazi1, 1992. [3] m.m. mahdy, experimental investigation of low heat flux heat pipes with and without adiabatic suction or solar application, college of engineering, university of baghdad, 2005. [4] e. azad, theoretical and experimental investigation of heat pipe solar collector, experimental thermal and fluid science, 32(8) (2008) 1666-1672. [5] k. sivakumar, n.k. mohan, b. sivaraman, performance analysis of elliptical heat pipe solar collector, indian journal of science and technology, 4(1) (2011) 4-7. [6] a.q.m.a.b.n.a. majid h. majeed, experimental study of heat pipe operating with r-l34a, global journal of engineering research and technology, 3 (2013) 916. [7] t. brahim, m.h. dhaou, a. jemni, theoretical and experimental investigation of plate screen mesh heat pipe solar collector, energy conversion and 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 0 200 400 600 800 1000 1200 p la te t e m p e ra tu re ( o c ) radaition incident (w/m2) figure (20): the impact of radiation incident on plate temperature for ambient temperature 27oc volume rate = 3.75 l/h volume rate = 4.35 l/h volume rate = 10 l/h 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 30 35 40 45 50 55 60 65 70 c o ll e ct o r e ff ic ie n cy plate temperature (oc) figure (21): the impact of plate temprature on the collector efficiency for different ambient temprature twin = 12oc ambient temperatur 27oc ambient temperature 20oc 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 c o ll e ct o r e ff ic ie n cy (tamb-twin)/g figure(22): the impact of [(tamb-twin)/g ]on the collector efficiency for flow rate 3.75l/h 0.45 0.5 0.55 0.6 0.65 0.7 0 0.02 0.04 0.06 0.08 c o ll e ct o r e ff ic ie n cy (tamb-twin)/g figure (23): the impact of [(tamb-twin)/g ]on the collector efficiency for flow rate 4.35l/h basil n. merzha et. al /al-qadisiyah journal for engineering sciences 12 (2019) 090–097 97 management, 87 (2014) 428-438. [8] j.a. duffie, beckman, w. a., solar engineering of thermal processes, john wiley & sons, inc, 1991. [9] k. hollands, t. unny, g. raithby, l. konicek, free convective heat transfer across inclined air layers, journal of heat transfer, 98(2) (1976) 189-193. [10] b. sivaraman, n.k. mohan, analysis of heat pipe solar collector with different heat pipe parameters, international energy journal, 8(2) (2007). [11] s. chi, heat pipe theory and practice, washington, dc, hemisphere publishing corp.; new york, mcgraw-hill book co., 1976. 256 p., (1976). [12] b. rashidian, m. amidpour, m.j. nasr, modeling the transient response of the thermosyphon heat pipes, in: proceedings of the world congress on engineering, 2008, pp. 2-4. [13] h. hussein, theoretical and experimental investigation of wickless heat pipes flat plate solar collector with cross flow heat exchanger, energy conversion and management, 48(4) (2007) 1266-1272. [14] t.l. bergman, f.p. incropera, a.s. lavine, d.p. dewitt, introduction to heat transfer, john wiley & sons, 2011. [15] comsol, introduction to comsol multiphysics, in, 2017. [16] h.g. hameed, numerical and experimental study of flow and heat transfer enhancement in a cylindrical heat pipe using nanofluid, university of basrah, 2015. [17] o.t. fadhil, numerical and experimental study on a heat pipe with porous media wick, university of technology, 2006. [18] k.f. kreider f.j. , solar heating and cooling: engineering, practical design, and economics,, washington dc:washington dc, (1977). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 398 effect of some factors in the friction stir welding on tensile strength of al-zn-mg alloy. waleed t.rashid production and metallurgy engineering department, university technology/baghdad emil: waleed_eng99@yahoo.com received 42 may 2015 accepted 21 jully 2015 abstract friction stir welding ( fsw ) is a solid –state process that leads to several advantages over the fusion welding methods. this is used in the welding of several non-expendable and is also responsible for generating sufficient heat for welding and the resulting friction. rotational speed, as well as the welding speedboth play a major role to obtain the weld quality. this research examines the effect of the rotation speed and welding speed on the tensile properties of the al-zn-mg by the minitab 16 program used. it was concluded that the best tensile strength of (158mpa) can be obtained when the variables were (x1 = 900 rpm) (x2 =52mm\min).also results show that the variables, namely the rotation speed (x1) &welding speed (x2) have a significant effect on tensile strength. however, the interactions of these factors have less significant effect on tensile strength. moreover, the tensile strength increases with the increasing welding speed and decreasing rotation speed. keyword: friction stir welding, al-zn-mg alloy ,tensile strength, hardness, rotation speed, welding speed. تأثير بعض متغيرات لحام الخلط االحتكاكي على مقاومة الشد لسبيكة ألمنيوم زنك مغنيسيوم شدليد تركي راو بغداد قسم هندسة أإلنتاج والمعادن الجامعة التكنولوجية الخالصة: فهي يسهتخدم . األنصهاايي عن اللحام متقدمة ميكانيكية بخواص يتميز والذي الصلبة الحالة لحام أنواع منلخلط االحتكاكي لحام يعتبر السهرعة و الدويانية السرعة .االحتكاك عن الناتجة و للحام الحراية الكافية توليد عن مسئولة تكون والتي مستالكة غير عدة اللحام هذا يتنهاول ههذا البحهر دياتهة تهسرير تهرعة الهدويان والسهرعة الخطيهة . للحهام جيهدة نوعيهة على الحصول في دوي يئيسي انتلعب الخطية ( والتهي يمكهن 158mpa. تم اتتنتاج أن أفضه مقاومهة هد minitab16باتتخدام برنامج al-zn-mg لسبيكة مقاومة الشد على تبههين مههن النتههائج أن (. كههذل x2= 52mm\min( وتههرعة الخطيههة x1=900rpm تههرعة الههدويانالحصههول علياهها عنههدما تكههون المشهترك للمتغيهرات يكهون ا ه التهسرير إنالخطية لاما تسرير معنوي على مقاومة الشد,على ك حهال الدويان والسرع عالمتغيرات تر .الدويان الخطية وانخفاض ترع سرعال على مقاومة الشد. باإلضافة إلى أن مقاومة الشد تزداد مع زيادة أهمية mailto:waleed_eng99@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 399 1-introduction: friction stir welding (fsw) is one of the new methods of welding developed nowadays. friction stir welding is a solid state welding process. the fsw technique is attractive for joining high strength aluminum alloys since there is far lower heat input during the process compared with conventional welding processes such as tig, mig [ericsson,2003][ thomas,2002]. this process is being used in a wide variety of applications in the automotive, aerospace, ship building, and railroad industries [rendigs,1997]. in fsw, the interaction of a non-consumable and rotating tool with the work pieces being welded, creates a welded joint through frictional heating and plastic deformation at temperatures below the melting temperature of the alloys being joined. based on the friction heating at the contacting surfaces of two sheets to be joined, a special tool with a properly designed rotating probe travels down the length of contacting metal plates, producing a highly plastically deformed zone through the associated stirring action [arbegast,2007].the friction stir welding method of joining is based on the fact that the metal is subjected to heavy plastic deformation at high temperatures, but lower than the melting point, thus the basic concept of the fsw is remarkably simple, where a rotating tool with the pin and shoulder is inserted in the material to be welded, and traversed along the line of interest as shown in fig.1[qasim,2010]. the tool serves three primary functions (1) the heating of the work piece, (2) the movement of material to produce the joint, and (3) the containment of the hot metal beneath the tool shoulder , the heating is generated by the friction between the rotation tool (shoulder and probe) and the work piece and by the plastic deformation of the work piece. the localized heating softens the material around the tool probe and then it combines with the tool shoulder and probe rotation and translation further leading to the movement of the material from the front to the back of the probe to fill the hole in the tool wake as the tool moves forward. [kumar,2008] investigated the influence of the axial load and the position of the interface with respect to the fact that the tool axis on the tensile strength of the friction stir welded joint has been investigated. the axial load is continuously varied by linearly increasing the interference between the tool shoulder and the surface of the base material; the base material used is al-zn-mg alloy, 7020-t6, and it is found that there is an optimal axial load above which the weld is defect-free. [gaafer,2010]studied the mechanical and micro structural characteristics of friction stir-welded aa7020-0 aluminum plate. it has been found that increasing the tool rotational speed and/or reducing the welding speed increase the primary al phase grain size as well as the size of the precipitates at the center of the stirred zone. the tensile characteristics of the friction stir welded tensile samples depend significantly on both the tool rotational and welding speeds. in this research, the experiments are designed and the experimental data are analyzed using the software minitab 16.a correlation is established between input parameters and mechanical properties. the anova is employed to investigate the influence of the input parameters, namely the rotational speed(x1) and welding speed (x2) on the tensile strength of the weld. [morteza,2013] dealt with evaluation of dissimilar welds of 5083-h12 and 6061-t6 produced by friction stir welding. states that as the conventional fusion welding is not desirable for welding aluminum alloys, there are many works conducted on welding the aluminum alloys by fsw. these works are in regard to the effects of fsw parameters on weld quality, sheet formability after fsw, and optimization of the fsw process. [divya,2014]study the optimization of fws parameters for 6061 and 7039 aluminum alloys by rsm. 2-experimental procedure: the chemical composition of al-zn-mg alloys is given in table 1, and here, a machine was used in the welding process as shown in fig.2a. the welded plates were (200 mm) in length, (100 mm) in al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 400 width, and (5 mm) in thickness as shown in fig.2b, then two equipped aluminum pieces were clamped into the fixture. plate edges to be weld were also prepared so that they are fully parallel to each other. then the rotating tool was made to be inserted into the butt joint. then after some time, when there was adequate heating due to the friction between the tool and plates, the tool was given an automatic feed, along the joint direction. thus the welding was achieved. after welding, the pieces were cut into the samples of mandatory dimensions for performing the tensile tests (y). the welding tool used in this study was made of tool steel with 18mm shoulder diameter, 6mm pin diameter and 6 mm pin length . fig.3 indicates that the tool design was used for the fsw process. the tensile strength of the fsw al-zn-mg was measured by the (3)mm thickness plate specimens-those were extracted in perpendicular to the weld direction from the (5) mm fsw plate as shown in fig. 4. in these tensile specimens, the weld surface and root surface were removed with the layers measuring (1) mm in thickness. the tensile test specimen are prepared according to th astm-e8m standards. the levels of the model were shown in table 2.the design matrix and experimental result are shown in table 3. 3-1 statically analysis: based on the experimental results table 4, the linear regression model used minitab 16.the regression equation is given in equation 1 and equation 2. y=12.342+1.202x1+0.187x2+0.030x1 2 -o.o16x2 2 +0.020x1x2 (1) the significant p-value is 0.05, and any value greater than this is regarded as insignificant and can be neglected. the regression equation can be re-written as such, y=12.342+1.202x1+0.187x2 +0.020x1x2 (2) where the variables represent (x1) (x2) or namely the rotational speed and welding speed respectively, (y) represents the tensile strength. it is noted from equation (2), that the rotational speed (x1) has the greatest influence on the tensile strength, while the impact of welding speed (x2) has less effect compared to (x1).in addition to the effect of the variables individually, it is also observed that there is a shared effect of the variables on the tensile strength. fig.5 shows the stress-strain curve for the less tensile strength, amounting to(122mpa). 3-2 analysis of variance (anova): the anova test was used to determine that the design parameters significantly have an influencing power towards the tensile strength .depending on the level of significance (0.05) and using the test (ftest) of the regression model, from table 5 , it is noted that the probabilistic value (p-value) is less than 5%, and this means that the regression model is significant [venkatprasa,2011]. this result is satisfactory. r-sq adjusted is equal to (92.09%), and this means that the independent variables (x1, x2) explain (92.09%) of the variables that occur in variable (y) and the remainder is due to other factors such as random error. whenever the coefficient of determination is closed one of the best and this can be satisfactory results. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 401 3-3interaction plot (between x1and x2): figure 6 illustrates the interaction effects of the control parameters; it is well known that any interaction does not occur when the line on the interaction plots is parallel and strong interaction will tend to occur between parameters when the lines cross[pascal,2009].an examination of the tensile strength as shown in figure 6 demonstrates a small interaction between the control parameters. 3-4 normal probability plot: the normal probability plot is a graphical technique for assessing whether or not a data set is approximately normally distributed. the data is plotted against a theoretical normal distribution in such a way that the points should form an approximate straight line. departures from this straight line indicate departures from normality. normal probability plots were generated by using computer software minitab16. in fig.7, it can be seen that all data residuals are approximately normally distributed because the overall points make an approximate straight line. 3-5 the main effect plot of tensile strength: fig. 8 shows the effect of the rotational speed and welding speed on the tensile strength and individual form. it is noted that the tensile strength decreases gradually with the increasing rotational speed and this is attributed by the high rotational speed results in the metallurgical transformation such as solubilisation, re-precipitation, and coarsening of strengthening precipitates at the weld zone and the lowering of the dislocation density which decreases the tensile strength. it is clear that in the fsw as the rotational speed increases the heat input also increases. these results almost agree with [palanivel,2011]. while the tensile strength improved with the rise in the value of the welding speed as the increase welding speed reduced the amount of the heat input, this enhances the tensile strength. these results agree with [saad,2007]. it is observed that the best result of the tensile strength was (158mpa) at lower rotation speed (900 rpm)and higher welding speed (52mm\min). 3-6 response surface analysis: the main objective of the response surface plot is to determine the optimum operating conditions represented by the rotational speed, also the welding speed, which lead to the maximum tensile strength required. fig.9 a and 9, show a contour and a three-dimension plot which describe the effect of factors (x1, x2) on response (y). the three-diminution plot shows that the tensile strength is affected by the rotational speed and the welding speed, whereas the contour plot shows an increase in the tensile strength with the decreasing rotational speed and the rise of the welding speed . it is observed that the value of the tensile strength was (155.646 mpa) at the rotational speed was (904.890 rpm) and the welding speed was (51.1777mm\min) whereas the value of the tensile strength decreases to (123.918) at the rotational speed was (1487.92 rpm) and the welding speed was (28.7811 mm\min). 3-7 pareto chart : fig. 10 shows the effect of variables (x1) and (x2) on the tensile strength (y) using the pareto chart. it has been observed that the rotation speed has the greatest influence on the tensile strength while the welding speed has a weaker influence on the tensile strength. the best result can be obtained , al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 402 according to the chart at the lower value of the rotational speed and the highest value for the welding speed. high rotational speed generates high temperature as a result of friction between the tool and the metal , when the increase of the rotation speed leads to a rise in the maximum temperature in the weld zone, as well as the fact that the welding speed has an effect on the inside heat to the weld zone. this heat decreases at low welding speed [venkatprasat,2011].therefore, the best result can be obtained when the rotation speed is decreased and the welding speed increased. 5-conclusions: 1possibility of using of fsw method in welding aluminum zinc alloy which are difficult welded by conventional methods. 2-regression models can be represented by the following equation y=12.342+1.202x1+0.187x2 +0.020x1x2. where the x1 and x2 have a significant effect on tensile strength ,and note that x1 has the greatest influence compared with that of x2. 3-the decrease in the rotational speed and increase in the welding speed lead to the increase and improvement of the tensile strength. acknowledgements: the author is grateful to the management and department of production and metallurgy engineering, university of technology, for assist and support of this work. refrences: m. ericsson and r. sandstro, “influence of welding speed on the fatigue of friction stir welds, and comparison with mig and tig”, international journal of fatigue, pp. 1379-1387, 2003. w. m. thomas, e. d. nicholas, e. r. watts and d. g. staines, “friction based welding technology for aluminum”, material science forum, pp. 1543-1548, 2002. k. h. rendigs, “aluminium structures used in aerospace-status and prospects”, material science forum, pp. 11-24, 1997. w. j. arbegast. “friction stir welding after a decade of development”, welding journal, pp. 28-35, 2007. qasim m. doos. suhair g. hussein, “ experimental investigation of temperature for stir friction welding distribution”, journal of engineering, no. 4 ,vol. 16,2010. kumar k, satishv.kailas,” on the role of axial load and the effect of interface position on the tensile strength of a friction stir welded aluminum alloy”.materials and design 29 ,6,pp.791-797, 2008. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 403 gaafer a.m., mahmoud t.s., mansour e.h.,” microstructural and mechanical characteristics of 7020-0 al plates joined by friction stir welding” material science and engineering a527pp.74247429, 2010. morteza ghaffarpour, sina kolahgar, bijan mollaei dariani, and kamran dehghani," evaluation of dissimilar welds of 5083-h12 and 6061-t6 produced by friction stir welding", doi: 10.1007/s11661-013-1739-2 ,the minerals, metals & materials society and asm international 2013. divya deep dhancholia, anuj sharma and charit vyas,” optimisation of friction stir welding parameters for aa6061 and aa 7039 aluminium alloys by response surface methodology (rsm)” international journal of advanced mechanical engineering, vol. 4, no. 5, pp. 565-571,2014. s.venkatprasat, r. subramaian, n. radhika, b. anandavel, l. arun and n. praveen, "influence of parameters on the dry sliding wear behavior of aluminum\flyash\graphite hybrid metal matrix composites",european journal of scientific resrarch,vol.53, no.2, pp.280-290, (2011). pascal deprez, philippe hivart, jean francois coutouly and etienne debarre, “friction and wear studies using taguchi method: application to the characterization of carbon-silicon carbide tribological couples of automotive water pump seals”, advances in materials science and engineering, 2009. r. palanivel, p. koshy mathews and n. murugan," development of mathematical model to predict the mechanical properties of friction stir welded aa6351 aluminum alloy", journal of engineering science and technology review 4 (1) ,pp25-31, 2011. saad ahmed khodir and shibayanagi toshita, "microstructure and mechanical properties of friction stir welding similar and dissimilar joints of al and mg alloys",jwri,vol.36,no.1,june 2007. elements zn mg mn si cu fe al al-zn-mg alloy 4.43 2.27 0.43 0.3 0.03 0.53 bal. no parameters code unit levels -1 0 +1 1 rotation speed x1 rpm 900 1200 1500 2 welding speed x2 mm\min. 28 40 52 table (1): chemical composition of al-zn-mg table (2): fws parameters and their levels al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 404 no run codes input parameters response (x1) (x2) rotation speed (rpm) welding speed (mm\min) tensile strength (y) (mps) 1 +1 +1 1500 52 131 2 0 +1 1200 52 140 3 -1 +1 900 52 158 4 +1 0 1500 40 128 5 0 0 1200 40 144 6 -1 0 900 40 151 7 +1 -1 1500 28 122 8 0 -1 1200 28 136 9 -1 -1 900 28 145 term coef t-value p-value constant 12.342 2.572 0.000 x1 1.202 -0.114 0.017 x2 0.187 1.444 0.011 x1*x1 0.030 -0.366 0.231 x2*x2 -0.016 -1.025 0.421 x1*x2 0.020 -0.621 0.041 source df seq ss adj ss adj ms f-value p-value regression 5 1017.11 1017.11 203.422 19.62 0.017 residual error 3 31.11 31.11 10.370 total 8 1048.22 s = 1.21026 r-sq = 97.03% r-sq(adj) = 92.09% table (3): design matrix and experimental result table (4): response surface regression: y versus x1,x2 table (5): analysis of variance for y al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 405 figure (2a): fsw machine. figure (2b): plate prepared for fsw. figure (1): schematic illustrations of the friction stir welding process [5]. al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 406 figure (3): fws tool. figure (4): specimen of tensile test. figure (5): stress strain curve (run5). al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 407 figure (6): interaction plot for tensile strength figure (7): normal probability plot of residuals of tensile strength al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 408 figure (8): main effect plot of residuals of tensile strength figure (9a): three-dimension plot of tensile strength al-qadisiyah journal for engineering sciences, vol. 8……no. 3 ….2015 409 figure (9b): contour plot of tensile strength figure (10): pareto chart for tensile strength article al-qadisiyah journal for engineering sciences 12 (2019) 161–166 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohammedabdulsada@gmail.com (mohammed abdulsada) https://doi.org/10.30772/qjes.v12i3.613 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. experimental investigation of the confinement effect on flashback in multi combustion modes tangential swirl burner haidar janna a and mohammed abdulsada a* a department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq. 1. introduction despite the continuing interest in the details of the designs of the mechanical parts of gas turbines, operational problems remain at the forefront of designers' attention where the requirements and conditions of operation have a clear role in the operational efficiency of the gas turbines and how to connect this operational problem represent by flashback with many issues such as fuel consumption and combustion efficiency and the provision of adequate stability of the flame resulting from the combustion of operating fuel taking into account the heat generated by these reactions to meet the turbine blades taking into account the burner body damage resulting from this operational problem. this study aims to reduce the occurrence of the combustion instability includes flashback by the development of the burner exhaust shape. this happened by adding the conical cup confinement to the open flame burner mouth as well as use the alternative fuel (lpg) as a working fuel to show the flashback behavior of the two cases and comparing the results for premixed combustion and partially premixed combustion modes. 2. theoretical approach flashback is one of the important operation problems in the lean premixed combustion which occurs when the turbulent propagation flame speed becomes faster than the flow velocity or mixture reactants incoming velocity. this leads to that the flame upstream to the premixed passage either burner tube or pre mixer [1, 2] the high temperature of flame a r t i c l e i n f o article history: received 22 august 2019 received in revised form 15 september 2019 accepted 25 september 2019 keywords: flashback premixed combustion tangential swirl burner liquified petroluim gas a b s t r a c t given the importance of gas turbines in the process and amount of global energy from fossil fuels, the views were directed toward this study in addition to the availability of the liquefied petroleum gas and because of knowing many details of it is composition and behavior this type of fuel has been proven. the development of the tangential swirl burner geometry also one of the targets of this study by reducing the combustion instability include flashback and the minimizing in the burner size comparing with other classic tangential swirl burner shape include cylindrical confinement with conical cup confinement. the authors take care in previous studies in field of swirling flow either in scope of geometry characteristics or in scope of fuel issues. the geometrical swirl number which play an important factor in swirling flow had been taken in the consideration for the process of the tangential swirl burner manufacturing as well as the heat caloric value of the operating fuel. the experimental results of combustion the liquefied petroleum gas had been proved that the formal additions added in this study to development the burner nozzle mouth will reduce and improve the occurrence of the operational problems represent flashback and an increasing in the working area by increasing the flashback limits for both premixed and partial premixed combustion modes which will be clarified and the mechanism of composition in the following sections of this paper. © 2019 university of al-qadisiyah. all rights reserved. http://qu.edu.iq/ mailto:mohammedabdulsada@gmail.com%20(mohammed https://doi.org/10.30772/qjes.v00i0 162 haidar janna and mohammed abdulsada /al-qadisiyah journal for engineering sciences 12 (2019) 161–166 cause hardware damage in the pre mixer or burner tube. the fuel content plays an important role in controlling the occurrence of flashback mechanism. some studies [3-6] refer to that the fuel containing hydrogen with swirl flow has a flame speed of four times greater than of natural gas. hence the flame speed being more than the inlet tangential velocity of the incoming mixture in tangential swirl burner [7-9], which can be calculated as the following way q = 2aw ( two tangential inlets ) (1) qf + qa = 2atiwti mixture (2) [ ṁf ρf + ṁa ρa ] = 2atiwti mixture (3) wti mixture = ṁf ρf + ṁa ρa 2ati → wti mixture = ṁf ρf + ṁa ρa 2πdti 2 4 (4) wti mixture = 2[ ṁf ρf + ṁa ρa ] πdti 2 , 2 πdti 2 = 270.973 (5) ∴ wti mixture = 270.973 [ ṁf ρf + ṁa ρa ] (6) in general, the place of occurrence and the turbulence of the flame speed is the most important factors that determine the type of flashback, which has been classified as follow: 2.1boundary layer flashback the velocity profile of the fluid flow as it known is approaching zero towards the wall edge in laminar flow cartesian coordinates. this low velocity ( critical velocity gradient gc) being lower than the flame speed (sf) space by a distance call as a quenching distance (∂q) and flashback take place [10]. gc = sf ∂q figure 1. schematic diagram of boundary layer flashback the main drawback of the above expression that it is not taken into account the heat transfer between the burner wall and the flame and that means there is a critical flow velocity gradient for each fuel. damköhler correlation (experimental data) and flame angle theory are the two methods used by hoferichter [11] to describe the boundary layer flashback with the turbulent combustion regime for hydrogen fuel. where the first theory is limited with turbulent combustion regime but the second gives reasonable results for boundary layer flashback. 2.2 turbulent core flashback a flashback occurs when the turbulent flame speed exceeds the flow velocity along some streamline, allowing the flame to propagate into the premixing section. this fact leads to the very simple design rule that the flow field must not have strong local velocity deficits and that the axial flow velocity must be substantially above the turbulent flame speed [12-14]. the swirl flames have high wrinkled and its high wrinkled mean increasing the surface area of the flame and this leads to that the flame speed being higher than its laminar value. 2.3 flashback due to combustion instabilities pulsation in the combustion system may be take place as a result of nonlinear interaction of pressure fluctuation and the periodic heat release. the fluctuation of heat release also flames speed which means the indirectly flame area in addition to the inlet velocity which at a certain level gives a nonlinear of heat release [15-17] represents the three factors play important roles in the fluctuation of heat release hence the combustion instabilities. 2.4 flashback due to combustion induced vortex breakdown (civb ) the sudden expansion in the burner exit (mouth) create central recirculation zone, this creation of crz can cause by different amount of heat release due to change in swilling or due to different type of fuel which also give different heat release then the crz which hold the flame extended to the burner base plate after that the flame re-establishes itself and cause upstream vortex to break down and the upstream flow region will appear due to the negative pressure gradient . the crucial factors in the civb are the fuel type (fuel blends ) and the burner geometry especially the burner mouth .in the field of fuel many studies investigate the effect of fuel on the civb flashback limits .some studies [5, 18, 19] reached that the behaviour of fuel mixtures different from the separate fuels ( individual contents ) while other studies [6, 8, 20] referred to the increase of hydrogen content in the fuel decrease the cibv flashback limits. the increase of equivalence ratio means increase the propagation of upstream flame and this leads to increase the possibility of civb take place. the changing from the blf to civb was investigated by baumgartner and sattelmayer [21] with increasing equivalence ratio and low swirl flow. other studies reach the same results but in other words where sayed [22] reaches the combustion induced vortex breakdown to occur more than boundary layer in high swirl flow .the diffuser position between the burner mixing tube and the combustor also can change civb flashback to blf [23]. the second field in investigations was the entry way of fuel or air which mainly affects the civb, the using of axial fuel injection which investigated by mayer [24] improves the resistance to the civb compared with trailing injection . the using of axial air injection [25] in lean premixed swirl-stabilized hydrogen combustion enhances the resistance to civb by reducing the axial velocity nomenclature q mixture volume flow rate [𝑚3 𝑠⁄ ] 𝑄𝑓 fuel volume flow rate[𝑚 3 𝑠⁄ 𝐴𝑡𝑖 𝑊𝑡𝑖 𝑔𝑐 𝑆𝑓 𝜕𝑞 crz civb blf lpg inlet tangential area [𝑚2] inlet tangential velocity [𝑚2 𝑠⁄ ] critical velocity gradient [1 𝑠⁄ ] laminar flame speed [𝑚 𝑠⁄ ] quenching distance [m] central recirculation zone combustion induced vortex breakdown boundary layer flashback liquefied petroleum gas 𝑄𝑎 𝜌𝑓 𝜌𝑎 �̇�𝑓 �̇�𝑎 ø ø𝑡 fb air volume flow rate [𝑚3 𝑠⁄ ] fuel density [𝑘𝑔 𝑚3⁄ ] air density [𝑘𝑔 𝑚3⁄ ] fuel mass flow rate [𝑘𝑔 𝑠⁄ ] air mass flow rate [𝑘𝑔 𝑠⁄ ] equivalence ratio [-] total equivalence ratio [-] flashback haidar janna and mohammed abdulsada /al-qadisiyah journal for engineering sciences 12 (2019) 161–166 163 and hence influence the vortex breakdown position. however, in spite of many studies in this field but the subject remains very difficult to research because of the interaction between heat and chemical reactions with different types of burner as well as the nature of use and different quality of fuel . micro surfaces of burner nozzle wall with use a properly central air injection are also play an important role in the reduction of boundary layer flashback and combustion induced vortex breakdown [26] . 3. experimental setup the tangential swirl burner consist of two tangential inlets has a circular section with internal and external diameters of 50 and 64 mm respectively to allow the mixture of fuel and air enter to the burner .the burner plenum which is the mixing zone or main swirling chamber has a diameter of 148 mm with a thickness of 7 mm. upper and lower flanges with asbestos gaskets of 1.5 mm thickness fixed by eight bolts which distributed around the circumference of these flanges. the burner nozzle has an internal diameter of 58 mm with thickness of 7 mm and length of mm to contribute in the swirling flow of the mixture coming from the two tangential inlets, thus the geometrical swirl number of the used burner has a value of 1.02. the burner exhaust geometry was one of the improvements on the burner represented by the addition of the conical cup confinements. the conical cup which is placed at the end of the burner exhaust with external diameter equal to the burner plenum diameter and internal diameter equal to the burner nozzle and length of half the burner plenum length. the use of conical cup confinement to investigate the flashback limits under variable shape conditions of the burner exhaust with several types of combustion modes including premixed combustion mode and partially premixed combustion mode. set of flow meters used in separate series forms to measure the mass flow rates of the mixture content include fuel and air where all the experiments were under the atmospheric conditions of 1 bar pressure and approximately 300 k temperature. a b figure 2. (a) open flame burner. (b) burner with conical cup confinement. 4. results and discussion in the premixed combustion mode, the combustible mixture of the fuel and air is injected together just from the two tangential inlets. firstly the fuel injected at a low level in other words low mass or volume flow rate and the oxidizer or air is injected gradually also from the tangential inlets. the operational fuel of this work is the liquefied petroleum gas ( lpg ) which is flammable mixture of 46 mj/kg heat caloric value and consist of 65% by volume butane ( 𝐂𝟒𝐇𝟏𝟎) and 35% propane ( 𝐂𝟑𝐇𝟖), whereas the density of lpg in the experimental conditions ( summer ) about 2.3151 kg/m3 . the flame in starting the combustion being near the nozzle mouth and with increasing the air mass flow rate then it will return to the burner plenum base plate accompanied by a loud voice which is the physical explanation of the flashback. thus with mixing 0.046 g/s of liquefied petroleum gas with 2.4 g/s mass flow rate for air, the mixture equivalence ratio being about 0.29 ( very lean mixture). the fig. 2. show the photos of the flame stages propagation, hence the flame grow at near the boundary layer of the internal nozzle mouth with a uniform stability and strength as shown in photo labeled a and then the central recirculation zone being clear in appearance taking the butterfly shape having a central location of the burner nozzle as shown in photo labeled b, this is due to the swirling flow effect inside the burner then the flame also the central recirculation zone has a longitudinal extension towards the burner base plate as shown in photos c and d. a b c d figure 3. photos of open flame burner in premixed mode �̇�𝒇 = 𝟎. 𝟎𝟒𝟔 𝒈/𝒔 , �̇�𝒂 = 𝟐. 𝟒 𝒈/𝒔 , ø = 0.29 164 haidar janna and mohammed abdulsada /al-qadisiyah journal for engineering sciences 12 (2019) 161–166 fig. 4. shows the results of experimental lpg premixed combustion, approximately linear behaviour in flashback limits with a quick transition from lean mixture to rich mixture, this quick transition due to some experimental difficulties. fig. 5. shows the effect of addition the conical cup confinement to the open flame burner which being not clear in the range of equivalence ratio less than 0.3 to show the flashback limits but it’s clear with increasing of the equivalence ratio where the enhancement rate of this addition here about 40% for 3.5 g/s compared with 2.7 g/s total mass flow rate (ø=0.83) as a 1.5g/s reference point. the figure shows similar behaviour for both cases of open flame burner and burner with conical cup confinement especially in very lean mixture but the working area being clear after 0.6 equivalence ratio, this is due to small amount of the oxidizer that the burner with conical cup confinement need it to reach to the flashback limits. figure 4. flashback limits of open flame burner in premixed combustion mode. figure 5. flashback limits comparison of open burner and burner with cup in premixed combustion mode. fig. 6. photo numbered 1 shows the liquefied petroleum gas flame near a boundary layer of the burner nozzle with an initiation of the central recirculation zone, then the central recirculation zone being more appearance with semi helical shape at the middle burner for this geometry of burner as shown in photo number 2. photo numbered 3 shows the starting of the crz backward flow in the direction of burner base plate. fig. 7. shows the flashback limits comparison of open flame burner and burner with conical cup confinement in terms of heat input and total mass flow rate with linear performance for both case due to the dependency of heat input on the liquefied petroleum gas heat caloric value and fuel mass flow rate. 1 2 3 figure 6. photos of burner with conical cup confinement flame in premixed combustion mode �̇�𝒇 = 𝟎. 𝟏𝟖𝟓 𝒈/𝒔 , �̇�𝒂 = 𝟑. 𝟑 𝒈/𝒔 , ø = 0.85 figure 7. flashback limits comparison of open flame burner and burner with conical cup confinement in premixed combustion mode as a function of heat input and total mass flow rate. partial premixed combustion elements are introduced through the use of the technique of combining the other combustion modes. this method involves the introduction of a very small amount of fuel through direct input volumetric flow rate through the fuel separate flow meter to measurement the diffusive mass flow rate and thus the diffusive stoichiometric ratio. the other way of entering the fuel is the two tangential inlets also through a set of valves and flow meters then air is injected from the only port of the air here which is from the two tangential inlets passing through the turbine flow meter and share with fuel to generate the premixed mode which also has a premixed stoichiometric ratio .the result of partial premixed combustion can be represented by a combination of premixed equivalence ratios for premixed and diffusive equivalence ratio for non-premixed to create the total equivalence ratio and compare it with the total mass flow rates of fuel and air. fig. 8. shows the experimental results of the flashback limits map for open flame tangential swirl burner in partial premixed combustion mode for both ranges of weak and rich equivelance ratios passing by the stoichiometric ratio. 1 2 3 4 5 6 7 8 9 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 t o ta l m a ss f lo w r a te [g /s ] equivalence ratio ø[-] 0 1 2 3 4 5 6 7 8 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 t o ta l m a ss f lo w r a te [g /s ] equivalence ratio ø [-] open flame burner with cup 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 t o ta l m a ss f lo w r a te [g /s ] heat input[kw] fb open premixed fb burner with cup premixed haidar janna and mohammed abdulsada /al-qadisiyah journal for engineering sciences 12 (2019) 161–166 165 figure 8. flashback limits of open flame burner in partial premixed combustion mode. once again, this mode of combustion sequence was used to show the percentage of improvement that the conical cup confinement adds to the limits of the flashback where the experimental results showed that adding of the cup directly to the burner improves the limits of flashback by 36% when comparing 5.3 g/s total mass flow rate with 4.25 g/s (i.e. øt = 0.87) as a 2.4 g/s reference point as shown in fig.9. figure 9. flashback limits comparison of open flame burner and burner with conical cup confinement in partial premixed combustion mode. 5. conclusions the flashback limits maps of the liquefied petroleum gas combustion has been proved that the addition of the conical cup confinement to the open flame tangential swirl burner improving these limits by maximizing the operational areas with different combustion modes by certain values especially in range of more than 0.3 equivalence ratios .it is clear from the enhancement rates and fuel consumption of the two combustion modes that the premixed combustion mode is better than the partial premixed combustion mode, this is due to the effect of the nonpremixed fuel which reduces the flashback resistance. it was also observed that the behavior of open flame burner and burner with conical cup confinement is almost similar, this is due to the proximity of the swirling zone from the combustion zone for the two burner geometries. references [1] g. baumgartner, l.r. boeck, t. sattelmayer, experimental investigation of the transition mechanism from stable flame to flashback in a generic premixed combustion system with high-speed micro-particle image velocimetry and micro-plif combined with chemiluminescence imaging, journal of engineering for gas turbines and power, 138(2) (2016) 021501. [2] a. kalantari, v. mcdonell, s. samuelsen, s. farhangi, d. ayers, towards improved boundary layer flashback resistance of a 65 kw gas turbine with a retrofittable injector concept, in: asme turbo expo 2018: turbomachinery technical conference and exposition, american society of mechanical engineers, 2018, pp. v04at04a060-v004at004a060. [3] a.c. benim, k.j. syed, flashback mechanisms in lean premixed gas turbine combustion, academic press, 2014. [4] m. abdulsada, n. syred, a. griffiths, p. bowen, effect of swirl number and fuel type upon the flashback in swirl combustors, in: 49th aiaa aerospace sciences meeting including the new horizons forum and aerospace exposition, 2011, pp. 62. [5] b. shaffer, z. duan, v. mcdonell, study of fuel composition effects on flashback using a confined jet flame burner, journal of engineering for gas turbines and power, 135(1) (2013) 011502. [6] n. syred, m. abdulsada, a. griffiths, t. o’doherty, p. bowen, the effect of hydrogen containing fuel blends upon flashback in swirl burners, applied energy, 89(1) (2012) 106-110. [7] v.-z.m. osvaldo, s. nicholas, v.-m. agustín, d.l.r.-u. daniel, flashback avoidance in swirling flow burners, ingeniería, investigación y tecnología, 15(4) (2014) 603-614. [8] m. abdulsada, n. syred, a. giles, p. bowen, tangential velocity effects and correlations for blow-off and flashback in a generic swirl burner and the effect of a hydrogen containing fuel, in: 51st aiaa aerospace sciences meeting including the new horizons forum and aerospace exposition, pp. 736. [9] m. abdulsada, n. syred, p. bowen, t. o'doherty, a. griffiths, r. marsh, a. crayford, effect of exhaust confinement and fuel type upon the blowoff limits and fuel switching ability of swirl combustors, applied thermal engineering, 48 (2012) 426-435. [10] c. eichler, t. sattelmayer, experiments on flame flashback in a quasi-2d turbulent wall boundary layer for premixed methane-hydrogen-air mixtures, journal of engineering for gas turbines and power, 133(1) (2011) 011503. [11] v. hoferichter, c. hirsch, t. sattelmayer, a. kalantari, e. sullivan-lewis, v. mcdonell, comparison of two methods to predict boundary layer flashback limits of turbulent hydrogen-air jet flames, flow, turbulence and combustion, 100(3) (2018) 849-873. [12] f. hatem, flashback analysis and avoidance in swirl burners, cardiff university, 2017. [13] r. szasz, a. subash, a. lantz, r. collin, l. fuchs, e. gutmark, hysteretic dynamics of flashback in a low-swirl stabilized combustor, combustion science and technology, 189(2) (2017) 266-289. [14] y.-c. lin, s. daniele, p. jansohn, k. boulouchos, turbulent flame speed as an indicator for flashback propensity of hydrogen-rich fuel gases, journal of engineering for gas turbines and power, 135(11) (2013) 111503. [15] j.h. cho, t. lieuwen, laminar premixed flame response to equivalence ratio oscillations, combustion and flame, 140(1-2) (2005) 116-129. [16] r. balachandran, a. dowling, e. mastorakos, dynamics of bluff-body stabilised flames subjected to equivalence ratio oscillations, in: proceeding of the european combustion meeting, 2011. [17] r. balachandran, b. ayoola, c. kaminski, a. dowling, e. mastorakos, 0 2 4 6 8 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6t o ta l m a ss f lo w r a te [ g /s ] total equivalence ratio øt[-] fb partial open flame fb partial burner with cup 0 2 4 6 8 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8t o ta l m a ss f lo w r a te [g /s ] total equivalence ratio øt [-] 166 haidar janna and mohammed abdulsada /al-qadisiyah journal for engineering sciences 12 (2019) 161–166 experimental investigation of the nonlinear response of turbulent premixed flames to imposed inlet velocity oscillations, combustion and flame, 143(1-2) (2005) 37-55. [18] t. lieuwen, v. mcdonell, e. petersen, d. santavicca, fuel flexibility influences on premixed combustor blowout, flashback, autoignition, and stability, journal of engineering for gas turbines and power, 130(1) (2008) 011506. [19] b. dam, g. corona, m. hayder, a. choudhuri, effects of syngas composition on combustion induced vortex breakdown (civb) flashback in a swirl stabilized combustor, fuel, 90(11) (2011) 3274-3284. [20] b. dam, n. love, a. choudhuri, flashback propensity of syngas fuels, fuel, 90(2) (2011) 618-625. [21] g. baumgartner, t. sattelmayer, experimental investigation of the flashback limits and flame propagation mechanisms for premixed hydrogen-air flames in non-swirling and swirling flow, in: asme turbo expo 2013: turbine technical conference and exposition, american society of mechanical engineers, 2013, pp. v01at04a010v001at004a010. [22] p. sayad, a. schönborn, m. li, j. klingmann, visualization of different flashback mechanisms for h2/ch4 mixtures in a variable-swirl burner, journal of engineering for gas turbines and power, 137(3) (2015) 031507. [23] t. sattelmayer, c. mayer, j. sangl, interaction of flame flashback mechanisms in premixed hydrogen–air swirl flames, journal of engineering for gas turbines and power, 138(1) (2016) 011503. [24] c. mayer, j. sangl, t. sattelmayer, t. lachaux, s. bernero, study on the operational window of a swirl stabilized syngas burner under atmospheric and high pressure conditions, in: asme 2011 turbo expo: turbine technical conference and exposition, american society of mechanical engineers, 2011, pp. 141-152. [25] t.g. reichel, s. terhaar, o. paschereit, increasing flashback resistance in lean premixed swirl-stabilized hydrogen combustion by axial air injection, journal of engineering for gas turbines and power, 137(7) (2015) 071503. [26] f. hatem, a. alsaegh, m. al-faham, a. valera-medina, c. chong, s. hassoni, enhancing flame flashback resistance against combustion induced vortex breakdown and boundary layer flashback in swirl burners, applied energy, 230 (2018) 946-959. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 612 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. study of noise pollution due to the sound amplifiers:case study comparison between local and modern market in diwaneyah city mukhtar dh. abbas, ministry of environment, al-qadissiyah environment directorate, aldiwaneyah – iraq. shubarmuktar@yahoo.comail: m-e mukhlis h. mojid, ministry of environment, al-qadissiyah environment directorate, aldiwaneyah – iraq. e-mail: muklis06@yahoo.com hiba a. majeed, ministry of environment, al-qadissiyah environment directorate, aldiwaneyah – iraq. e-mail: hibasalam@outlook.com received on 12 november 2017 accepted on 13 december 2017 published on 15 march 2018 doi: 10.30772/qjes.v10i4.507 abstract: the objective of this study is to identify the effect of the noise that result from sound amplifiers which have been used in local markets on the healthy and psychology of population (vendors and pedestrian). therefore, we measured the noise level in local and modern markets to identify the difference in noise level that create by sound amplifiers where we chose three points in each market at (north, mid and south) and for a period of seven days and comparison the readings of noise level of both markets with the iraqi standard. two questionnaires have been carried out in this study, the firs questionnaire is for the vendors. the second questionnaire represents the pedestrians.for a period of seven days, the average of the noise levels (leq) in local market for north, mid and south points were (77.2, 80.2 and 73.4) decibel (db) respectively while in the modern market were (66.2, 69.1 and 64.8) db respectively. the results of the first questionnaire showed that the vendors in local marked are more harmful than the ones in the modern market where most of them suffered from hear losing, annoying, boredom, mood flocculation, weakness of focus and other psychological effects but the harm ratio with hypertension was low in both markets. the results of the second questionnaire showed that the harm ratio of shoppers in local and modern markets with annoying equal to (92%, 17%), headache (58%, 25%), nervous(25%,25%), boredom (33%,25%), weakness of focus (58%,42%), nausea (67%,58%), respectively. these results give an impression that the sound amplifiers were the essential reason for increasing the noise level in local markets and the noise level higher than 70 db cause healthy and psychological effects for the vendors. keywords: noise, sound amplifiers, local market, modern market. mailto:shubarmuktar@yahoo.com mailto:muklis06@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 613 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. introduction noise pollution in cities has become a global concern because its seriousness and its problems to many activities such as transportation, commercial, industrial and constructional works. every nation concerns about the health effects of noise emitted from the expanding number of vehicles moving on the roads. [1]. the major source of noise in outdoor environment such commercial district is the transportation system such as taxies. however, at the local markets in diwaneyah city, the sound amplifiers are the hazard source of the noise where the vendors have used these devices as part of advertising about their goods. these sound amplifiers cause high levels of noise which they have been adversed impact on the population. in general, there are two categories of biologic impact that cause noise : auditory (hearing loss) and non-auditory effects such as annoying, sleep disorder, hypertension, impair cognation and effect outcome). [2]. noise pollution is a most important occupational hazard, temporary impact of noise exposure includes hearing loss, annoyance. permanent health impact of noise exposure results in hearing loss; both temporary and permanent impact can be avoided by timely recognition, assessment and control of noise pollution. [3]. many studies have been conducted about the healthy impact of the noise on the population. the most serious health impact is hearing loss which is resulting from permanent harm to the inner ear. [4]. generally, body pain and head ache were the most common health symptoms among people who were exposed to noise pollution. noise affects blood pressure regardless of gender and age of the individual.[5]. exposure to high levels of noise can affected humans, such as hypertension, psychological symptoms and vasoconstriction disease. [6]. the continuous exposure to the noise increases hypertension of male workers independently.[7]. the continuous exposure to levels of noise range (52.52 to 65.74) decibel causes a rise of hypertension and pulse rate [8]. many researchers have studied and evaluate the noise pollution in iraq and from them hussein janna who studied the effect of noise pollution on the schools and health centers in diwaneyah city [9].therefore, the objectives of this study were to measure the level of the noise and identify its impact on the population specially the vendors in the local market and compare it with modern market and finding the engineering solution to mitigate the noise. 1. area of study aldiwaneyah city placed in the middle of iraq (about 180 km south of baghdad) where the population is about (403,726) persons. figure 1: picture show the places of the local and modern markets. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 614 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the study area was commercial where we choose the largest two markets in this city, one of them is local in which the sound amplifiers have been used and compare it to the modern market where the sound amplifiers have not been used . these markets have same engineering properties length ,almost 500 meter, width, number of shops and almost the same goods as shown in the figure (1). 2. materials and method this study included three parts of work, the first part was measuring the level of the noise in two places local and modern markets with three points: north, mid and south in each one of the markets for a period of seven days and the period of each measure which was a quarter hour, then compare it together and with iraqi standard no. (41) 2015. the measure of the noise by using sound meter (svan 955) with 1.2meter-high and the side distance from any neighboring obstacle more than one meter. the second part includes questionnaire which specialized for the venders in both markets who remain in their work from ( 6 10) hours per day. the number of respondents were fifty (50) in each market with (13) questions about the psychological and healthy impact which included (hear losing, hypertension, annoying, headache, nervous, boredom, control and performance, nausea, mood fluctuation, sleep disorder and the desire to quarrel with client or neighboring). the last part using questionnaire specialized for 12 persons stayed for a period of two hours only in the first day in local market and repeat the same questionnaire with modern market for the same persons to determine the noise level impact on the shoppers. 3. results in this study, the researchers measure the noise level at three points (north, mid and south) in each market (local and modern ) for a period of seven days, the readings of noise levels (leq) at local market were as followed, in north the noise level was (73.7 to 81) db with average of 77.2 db and stdev 2.54. , in mid market the noise level was (74.1 to 85.6) db with average of 80.2 db and stdev 3.25 and in south was the noise level ranged (70.5 to 76) decibel (db) with average of 73.4 db and the standard deviation (stdev) of 1.86. in the north of modern market, the readings of noise level (leq) was (63.2 to 68.1) db with average 66.2 db and stdev 1.91, in the mid market, it was (66.6 to 74.5) db with average 69.1 db and stdev 2.6 and in south, it was ranged (62.6 to 67) db with average 64.8 db and the standard deviation (stdev) 1.48. figures 2,3 and 4 and table (1) show the above results. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 615 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: the noise levels in (leq) in north. figure 3: the noise levels in (leq) in mid. table 1: the readings of noise level in (leq) db. figure 4: the noise levels in (leq) in south. the readings of maximum noise level at local market were as following, in north, it was (92.2 to 102.2) db with average of 97.9 db and stdev of 4.01. , in mid market, it was (86.5 to 98.6) db with average of 93.1 db and stdev of 3.72 and in south was, it ranged (86.7 to 98.1) db with average of 91.2 db and the standard deviation (stdev) of 3.43. in modern market, the readings of noise level (max.), in north, it was (80.4 to 89.6) db with average of 85.3 db and stdev of 3.27, in the mid market, it was (83.2 to 93.7) db with average of 89 db and stdev. of 3.97 and in south, it ranged (76.4 to 82.7) db with average of 81.4 db and the standard deviation (stdev) of 3.29. table (2) shows the result of maximum noise level in local and modern markets. the readings of minimum noise level at local market were as following, in north, it was (60.4 to 63.4) db with average of 62.3 db and stdev. of 0.96, in mid market, it was (63.4 to 71.3) db with average of 68.3 db and stdev. of 2.94, and in south, it ranged (58.5 to 63.8) db with average of 91.2 db and the standard deviation (stdev) 3.43. in modern market, the readings of noise level (min.), in north was (55.1 to 58.4) db with average of 56.7 db and stdev. of 1.28, in the mid market, it was (55.2 to 58.4) db with average of 56.4 db and stdev. of 1.17 and in south, it ranged (55.2 to 57.7) db with average of 56.6 db and the standard deviation (stdev) of 0.88. figures 5,6 and 7 and table (2) show the above results. days leq local market modern market north mid south north mid south sun 74.2 74.1 70.5 65 66.9 67.0 mon 73.7 78.2 74 65.2 66.6 64.4 tues 81 80.2 75 65.5 74.5 62.6 wed 80 81.6 76 67.7 68.6 64.3 thurs 76.6 85.6 74.2 63.2 66.9 65.3 fri 76.6 80.3 73 69 70 66.6 sat. 78.1 81.4 71.1 68.1 70.2 63.5 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 616 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: the noise levels (max. and min.) in south. figure 6: the noise levels (max. and min.) in mid. . figure 7: the noise levels (max. and min.) in north. table 2: the readings of maximum and minimum noise level in (db). days max. min. local modern local modern north mid south north mid south north mid south north mid south sun 92.2 86.5 86.7 86.9 90.9 82.7 60.4 64.5 58.5 55.1 55.6 55.2 mon 97.3 91.6 92.3 80.4 83.5 82.8 61.9 63.4 61.3 56.5 56.3 57.6 tues 101 93.3 92.5 88.3 91.1 80.1 63 71.3 63.8 55.7 55.3 57.1 wed 102 95.1 98.1 85.1 93.7 87.1 62.7 71.2 63.4 56.8 55.2 57.7 thurs 92 96.1 88.2 80.8 83.2 78 61.6 70.1 59.7 55.1 56.1 56.6 fri 98.4 98.6 89.6 89.6 87.6 82.5 63.4 68.5 62.3 58.4 58.4 55.6 satur 102.2 90.3 91 86 92.8 76.4 62.9 69.4 60.2 58.3 57.9 56.6 the results of first questionnaire were included the healthy and psychological impacts for the vendors where the harm ratio of them in local and modern markets with hypertension equal to (62%, 4%), annoying (100%, 32%), headache (74%, 32%), nervous(57%,34%), boredom (89%,46%), weakness of focus (72%,36%), nausea (51%,12%), mood fluctuation (38%,40%), sleep disorder(60%,30%), the desire to quarrel with client (53%, 14%) and hear losing (23.4%,4%) respectively. figure (8) and table (3) explain the result of harm ratio of the vendors. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 617 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 8: ratio of healthy and psychological harm . table 3: ratio of healthy and psychological harm. the results of second questionnaire represent the shoppers by choosing twelve persons who stayed two hours in each market to investigate the psychological effects on them. the results of questionnaire indicate that the harm ratio of them in local and modern markets with annoying equal to (92%, 17%), headache (58%, 25%), nervous (25%,25%), boredom (33%,25%), weakness of focus (58%,42%), nausea (67%,58%). figure (9) and table (4) explain the comparison between the result of harm ratio of the shoppers in modern and local markets. question healthy and psychological harm % local market modern market hypertension 62 4 hearing loss 23.4 10 sleep disorder 60 30 annoying 100 32 weakness of focus 72 36 head ache 74 32 nausea 51 12 boredom and leaving work 89 46 nervous after work at home 57 34 mood fluctuate 38 40 take stimulants 83 50 the desire to quarrel with neighboring 38 14 the desire to quarrel with clients 53 14 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 618 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 9: ratio of psychological harm. table 4: ratio of psychological harm. 4. discussion from the results, it can be observed that the noise level in local market is higher than the noise level in modern market where in local the noise in (leq) ranged (70.5 to 85.6)db while in modern market ranged (62.6 to 70.2) db, this high noise which also higher than iraqi standard (65) db belongs to the using of the sound amplifiers in local market which are not used in modern market. because the high noise in local market, most of the vendors have suffered from healthy and psychological harm where the harm ratio in local market is higher than modern market. more than that, the annoying level in local market reached up to 100% but the hearing loss in local markets is (23.4%) and very low in modern market which is about (10%). never the less, the noise level in modern market cannot affect population (vendors or shoppers). the second questionnaire which represent the shoppers showed that the psychological effects in local market are higher than the ones in modern market especially annoying which was (92%, 17%) respectively. but the harms ratio of the head ache, nausea, boredom and leaving shopping, nervous and weakness of focus were equal in both markets. questions healthy and psychological harm % local market modern market annoying 92 17 weakness of focus 58 42 head ache 58 25 nausea 67 58 boredom and leaving shopping 33 25 nervous 25 25 take stimulants 33 17 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 619 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. conclusions the sound amplifiers were the essential cause in height the noise level in local markets. the noise level high than 70 db cause healthy and psychological effects for the vendors. the noise level with 60 db cannot affect population (vendors or shoppers). references 1. n. garga, a. kumarc, p.k. sainid and s. majib , "a retrospective view of ambient noise standards in india: status and proposed revisions", institute of noise control engineering india, 2015. 2. mirsaeed attarchi, faezeh dehghan, farnaz safakhah, marzieh nojomi and saber mohammadi ," effect of exposure to occupational noise andshift working on blood pressure in rubber manufacturing company workers" national institute of occupational safety and health,iran,2012. 3. shubhang mishra and dr. v. k. sukhwani , " changing paradigm of industrial noise control: a review" asian journal of engineering research, issn-2319–2100,india ,2013. 4. deborah imel nelson, robert y. nelson, marisol concha-barrientos, marilyn fingerhut , " the global burden of occupational noise-induced hearing loss" the american journal of industrial medicine, u.s.a, 2005. 5. gayathri .k, a. amutha jaisheeba and r. sornaraj ," physical and cardiovascular implications of noise pollution prevailed in thoothukudi the industrial city, tamilnadu, india". international journal of chemtech research, issn : 0974-4290, india,2012. 6. sameer kumar, gaurav kumar, kunal gupta and rajeev kumar mishra ," traffic noise analysis at road side hospitals during peak hour traffic flow" innovative energy technology systems and environmental concerns: a sustainable approach :isbn: 978-93-84144-81-4, india, 2014. 7. lee jh, kang w, yaang s, choy n, lee c, "cohort study for the effect of chronic noise exposure on blood pressure among male workers in busan, korea". am j ind med 52, 509–17.,(2009). 8. abu hamda ,marwan hamdi said , "effects of noise exposure on blood pressure and pulse rate of employees in intensive care units in gaza strip-palestine" m.sc. thesis, islamic university of gaza, the islamic university – gazapalestine,2013. 9. janna, hussein , " noise levels assessment in selected places in al-diwaniyah city, iraq" al-qadisiyah journal for engineering sciences, iraq ,2016. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 555 improve the performance of voice-excited lpc vocoder in speech coding application assistant lecturer: awwab qasim jumaah althahab assistant lecturer: ahmed hussein shatti alisawi electrical engineering department, collage of engineering, university of babylon email: eng.awwab.qasim@uobabylon.edu.iq email: eng_ahmed.shatti2014@yahoo.com received 3 august 2015 accepted 21 october 2015 abstract one of the fundamental problems in the area of digital speech processing is a speech coding that has been studied for years. speech coding simply transforms the speech signals as fewer numbers of binary digits as possible, which can be then transmitted through channels or stored in memory devices. due to the fact that the bandwidth of the channels is not unlimited, speech compression is needed to let more space bandwidth; thereby more speech coded signals can be sent over same channel bandwidth. linear predictive coding (lpc) that is based on linear prediction (lp) model, which is a method to represent and analyze human speech, is one of the most common speech coding techniques. it is used in compression the digital speech signals, resulting low bit rate. this method has become the dominant technique for determine the fundamental speech parameters such as pitch, formants, spectra, vocal tract area functions. however, the weakness of lpc is in estimating the fundamental speech parameters causes poor voice quality and performance. the aim of this paper is to build a system with precise detection of speech parameters for encoding a better speech quality at low bit rate. this can be done through proposing a modified version to the voiceexcited lpc vocoder based on discrete cosine transform (dct) and quantization of residual error while retaining low bit rate; hence conserve the bandwidth. segmental power signal to noise ratio (segpsnr) and mean square error (mse) as an objective measure for speech signal quality are implemented for the proposed improvement through computer simulation using matlab 11. keywords: voice-excited lpc vocoder, levinson-durbin recursion, iir filters, discrete cosine transform (dct), mean square error (mse). اداء الترميز الصوتي التنبؤي الخطي المثار في تطبيقات تشفير الكالم تحسين العيساوي مدرس مساعد: اواب قاسم جمعة الذهب مدرس مساعد: احمد حسين شاطي قسم الهندسه الكهربائيه, كليه الهندسه, جامعه بابل الخالصة لكالميمكن تعريف تشفير ا. الذي درس لسنوات تشفير الصوت الرقمي هوالكالم واحدة من القضايا الرئيسية في مجال معالجة الى اقل عدد ممكن من االرقام الثنائية والتي تنقل بعدها عبر القنوات او تخزن في اجهزة لكالمتحويل اشارات ا على انه ببساطة mailto:awwab.qasim@uobabylon.edu.iq mailto:eng_ahmed.shatti2014@yahoo.com al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 555 لكي نسمح فراغات اكثر في كالمالذاكرة. بسبب الحقيقة بان عرض الحزمة للقنوات الناقلة لالشارة محدودة, لذلك نحتاج ضغط ال (، lpcالترميز الخطي التنبئي )له عبر نفس قناة النطاق الترددي. النطاق الترددي وبالتالي المزيد من الكالم المشفر ممكن ارسا الصوت إشارات ضغط في تستخدم والتي شيوعا كالماكثر تقنيات تشفير ال هو واحد من، كالم البشر وتحليل لتمثيل الذي هو طريقة االساسية مثال كالمحسابات خصائص الهذه الطريقة اصبحت تقنية سائدة في الترميز. معدل بت انخفاض، مما ينتج عن الرقمية ( نوع ضياعي من lpc)ولكن الضعف في حسابات خصائص الكالم تجعل النغمة, االصوات, الطيف ودوال الجهاز الصوتي. دقيق لخصائص الكالم الكشف الانواع الترميز ويسبب ضعف في اداء وجودة الصوت. الهدف من هذا العمل هو بناء نظام مع نسخة محسنة من الصوت المثار قتراحالترميز. ويمكن القيام بذلك من خالل ا معدل بت جودة كالم في انخفاضلترميز افضل بت انخفاض معدل مع الحفاظ على المتبقي الخطأ و تكميم (dct)باالعتماد على تحويلة (velpc)للترميز التبؤي الخطي ومتوسط مربع االخطاء (segpsnr)بة قدرة االشارة الى الضوضاء عرض النطاق الترددي. نس الحفاظ على وبالتالي ,الترميز (mse) 11باستخدام ماتالب الكمبيوتر محاكاة من خاللالمقترح تحسينللنفذت كمقياس موضوعي لجودة اشارة الكالم . الكلمات المفتاحية: الترميز الصوتي التنبؤي الخطي المثار, المرشحات ذو االستجابة الترددية االنهائية, تحويلة .(mse) , متوسط مربع االخطاء 1. introduction the fundamental purpose of signal compression techniques is to reduce the number of bits required to represent a signal (speech, audio, image and video) while keeping an acceptable signal quality for the purpose of reaching the communication system target of low bit rate transmission or message encryption (marcelo and valdemar, 2005). speech coding is the process of transforming the speech signal at hand, to a more compact form, which can then be transmitted with a considerably smaller memory. the motivation behind this is the fact that access to unlimited amount of bandwidth is not possible. therefore, there is a need to code and compress speech signals. for example, in digital cellular technology, many users need to share the same frequency bandwidth. utilizing speech compression makes it possible for more users to share the available system. another example where speech compression needed is in digital voice storage. for a fixed amount of available memory, compression makes it possible to store longer messages. one of the most powerful speech analysis techniques is the method of linear predictive analysis that is uses (lpc) vocoder (daniele et al., 2014). the speech features such as pitch, formants, spectra and vocal tract transfer function can be all estimated using this type of technique. the good extracted parameters result good reconstructing the speech signal and then more intelligible speech. the weakest link in most lpc vocoders is estimations and representations of the excitation functions (especially the pitch period of excitation signal) (marcelo and valdemar, 2005). in this vein, (yugandhar and satyapriya, 2013) presented and implemented three coding techniques (lpc, waveform and sub-band coding), checking their performance measures such as compression ratio and speech audible quality. in (minal and sonal, 2014), the authors proposed a system to implement a model based design by using the linear prediction coefficients of the encoded speech data and prove to be the promising method for speech compression. (jingyun et al., 2014) presented a linear prediction model that is based on first order norm. they proposed a method based on linear programming to calculate the parameters of the model and analyze the performance of the first order norm. a great challenge in digital coding of signals is the development of methods for assessing the quality of reconstructed signals. in this paper, for more accurate estimation of speech parameters, a modification on the voice-excited lpc vocoder based on discrete cosine transform (dct) is proposed for coding two male wideband speech signals. the measure used for assessing the quality of signals may be classified into two general groups: subjective quality and objective quality measures. for the purpose of this paper, the speech coder developed is evaluated using the objective measure, which is based on a direct mathematical comparison between the original and (dct) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 processed signals. the objective analysis that will be performed consists of computing segmental power signal to noise ratio (segpsnr) and mean square error (mse) between the original and the coded speech signals. furthermore, the effect of quantizing the residual error on bit rate is studied. the remaining of the paper is organized as follows: section 2 demonstrates the speech production model and how speech can be represented as the output of a linear time varying system. in section 3, the proposed modification to find the optimum estimation of speech parameters is discussed and presented. in section 4, the performance of the proposed approach is evaluated using computer simulation in matlab 11. the paper is finished with some concluded remarks. 2. speech production figure (1) depicts the simple speech production model. speech is produced when an air being pushed from the lungs through the vocal tract, and out through the mouth to generate speech. in this type of description the lungs can be thought of as the source of the sound and the vocal tract can be thought of as a filter that produces the various types of sounds that make up speech (lawrence and ronald, 2009). speech signals consist of several sequences of sounds, which can be classified into voiced and unvoiced. the fundamental difference between these two types of speech sounds comes from the way they are produced. voiced sounds are produced by vibrating the vocal cords due to the air comes from the lungs. the rate at which the vocal cords vibrate dictates the pitch of the sound. however, unvoiced sounds do not rely on the vibration of the vocal cords. the unvoiced sounds are created by the constriction of the vocal tract that is modeled as a linear all pole filter (infinite impulse response filter). the vocal cords remain open, and the constrictions of the vocal tract force air out to produce the unvoiced sounds (lawrence and ronald, 2009). now, speech can be modeled as the output of a linear time varying system (iir filter), excited by either quasiperiodic impulse train or white noise to generate various components of speech. during the production of a given speech signal, the encoding process of lpc analyzer uses to successfully predict and estimate a set of accurate parameters for modeling the vocal tract (all pole filter). the predictor parameters determined by minimizing the residual error, which is the sum of the squared differences between the actual speech signal and the linearly predicted one over frames of a finite duration, which is normally 20 ms long (john et al., 1999). only the predictor coefficients and residual error are sent instead of sending original speech signals. decoding process involves using the error and predicted parameters received to build a synthesized version of the original speech signal. the transfer function of the time-varying digital filter is given by (lawrence and ronald, 2009). ( ) ∑ ( ) ( ) (1) where are the gain, order and parameters of iir filter. only the first coefficients are transmitted to the lpc synthesizer. the most common methods used to determine the coefficients are the covariance and the auto-correlation methods. for our implementation, the auto-correlation method will be used. the reason is that this method is superior to the covariance method in the sense that the roots of the polynomial in the denominator of the above equation is always guaranteed to be inside the unit circle; hence the system ( ) is for sure stable (awwab, 2013; carlo et al., 2009). the levinson durbin algorithm will be used in our simulation to compute the required parameters for the auto-correlation method. https://www.google.iq/search?hl=ar&tbo=p&tbm=bks&q=inauthor:%22john+r.+deller%22 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 3. the proposed modification on velpc model the classic approach to analyze human speech based on lpc showed poor sound quality, the voice excitation is the weakest portion of this method (yi and philipos, 2008). therefore, voice-excited linear predictive coding (velpc) is one approach to get better sound quality. a system of this type has been studied by (thomas and abeer, 2011). figure (2) shows a block diagram of velpc with excitation detector. the proposed modification on the model shown in figure (2) and will be made in simulation is to use a pre-emphasis filter. it is used to make the spectrum as flat as possible by boosting the high frequencies in order to get a better result for estimation of the predictor parameters. obviously, the predictor coefficients corresponding to higher frequencies can be better estimated. this kind of treatment is within the reconstruction part of the speech signal. the input speech signal that is divided over finite duration of times (frames) is filtered by the estimated transfer function of linear predictive coding analyzer. the output of the analyzer is called the residual (error signal) that is sent with the predictor coefficients to the receiver. consequently, a very good speech quality can be achieved. however, the trade off paid of this system is a high bit rate; therefore, one solution to reduce the bit rate to16 kbits/sec is to use discrete cosine transform (dct) to the residual error. the fact behind the use of dct is only the low frequencies of the residual signal are needed in order to maintain a good reconstruction of the excitation. the dct concentrates most of the signal energy in the first few coefficients that will be then sent to achieve a high compression rate. another process that will be executed in our simulations is shown that those dct coefficients could be quantized using 4, 6 and 8 bits instead of 16 bits which is the original representation. the quantized process is based on the partial reflection coefficients (prc), which are the average values during the calculation of the well-known levinson-durbin recursion. finally, the receiver simply performs an inverse dct and uses the resulting signal to excite the voice. from equation (1) and from the concept of speech production model, where current speech sample [ ] is approximated as a linear combination of past samples: [ ] ∑ [ ] [ ] (2) where [ ] is voiced or unvoiced sounds and is sample index. a linear predictor with prediction coefficients is define as a system whose output is ̃[ ] ∑ [ ] (3) the prediction error (excitation) is the difference between the observed and predicted signals, and it is assumed to be independent and identically distributed process (i.i.d) (john, 1975). [ ] [ ] ̃[ ] (4) substituting (3) into (4); yields [ ] [ ] ∑ [ ] (5) let now suppose that the prediction error filter can be represented as ( ) ∑ (6) then ( ) ( ) ( )∑ ( )[ ∑ ] ( ) ( ) (7) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 if the coefficients of the predictor ( ) converges exactly to ( ), the error becomes [ ] [ ] (8) or ( ) ( ) (9) but from equation (7), ( ) ( ) ( ), substituting (7) into (9) and reallocate the terms, yields ( ) ( ) ( ) (10) from (1) and (10), we can conclude that ( ) ( ) (11) equation (11) shows that the prediction error filter ( ) (it is also called the analysis filter) is the inverse filter of the system ( ), the synthesis filter. the optimization problem aims to find an estimate of the prediction coefficients from a set of observed real samples such that the prediction error is minimized (stephen and lieven, 2004). the resulting values are then assumed to be the parameters of the system function ( ) which will be then used for synthesizing speech segments. to minimize the error, let [ ] set of past values of speech signal [ ] are given; where is the order of prediction error filter and equation (3) can be written as ̃[ ] ∑ [ ] [ ] [ ] [ ] (12) ̃ ∑ (13) according to (13), the prediction error is now written as: ̃ ∑ (14) to find the predictor coefficients, the first order derivative is taken with respect to the predictor coefficient to the mean squared error and equating the result to zero as in (15). { [ ∑ ]( )} (15) rearenging (15), yields { } { ∑ } (16) setting and define covariance [ ], and [ ], (16) will be written as [ ] [ ][ ] (17) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 equation (17) can be solved using the so-called levinson-durbin algorithm (george, 1980). in our simulations to the proposed scheme, objective measure of speech quality takes a mathematical criterion to analyze the performance and compare the origin with the reconstructed speech signals. segmental power snr is calculated by first measure the snr of each frame, then, take the average during the speech and it is defined in equation (18). also, the mean square error (mse) is calculated and defined by the equation (19). ∑ ∑ ( ) ∑ ( ) (18) and ∑ | ( )| (19) where is the frame length, is the number of frames, ( ) is the original speech of the points of the frame, and ( ) is the residual error of the points of the frame (colin and rainer, 2011). 4. performance analysis and simulation results the speech signals that will be coded are wideband signals. we utilize a modified version of voiceexcited linear predictive coding (mvelpc) to code 2 males with the same phrase sentence (welcome to the university of babylon). the typical set of parameter values that have been used in our simulation results is as follows: the bandwidth of the speech signals is 8 khz, the sampling frequency has to be at 16 khz with a maximum end-to-end delay of 100 ms and length of each frame is 20 ms which results in 320 samples per frame. for perfect reconstruction, the overlapping length have to be 10 ms; hence the actual frame length is 30 ms which contains 480 samples, resulting 50 frames per second. the bit rate of original speech is at 250 kbps whereas the bit rate of synthesized speech is calculated in table (1). take into consideration the variation on the number of bits in quantization process and then multiply the result by 50 (number of frames per second); the bit rates are finally obtained. figure (3) shows the original and the reconstructed speech signals based on mvelp vocoder with different quantized representation to the residual error (different no. of bits in quantization process). as can be seen from the figure, the reconstructed signal has a lower quality than the original signal when 4 bits used since there is a clear difference in shape between them. however, the similarity increases when the number of quantizing bits is raised, but does not sound exactly like the original speech signal. segmental psnr and mse are measured as can be seen in table (2) and (3) for wave files (ahmed.wav) and (ali.wav), respectively. it is obvious from the values estimated that the reconstructed signals based on classic lpc have been very noisy since having very low segpsnr and high mse. meaning, the noise is stronger than the actual signal. however, the reconstructed speech signal that is based on the mvelpc vocoder sounds far better and its segpsnr is good enough. the segpsnr is increasing while mse is decreasing when the number of bits is rising from 4 to 8 in the quantization process to the residual error whereas maintaining low bit rate, not exceeding 16 kbps. the velpc vocoder is also implemented and the results obtained, as can be seen in table (2) and (3), are superior than both the classic lpc and mvelpc, but it demands a very high bit rate. this explains why the proposed system is desirable compared to what is achieved from other types of speech coding techniques such as velpc, waveform and subband coders that require a very high bit rate for transmission. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 a frame number 20 is selected from wave file (ahmed.wav), plus 240 points hamming window. the frequency response is estimated and plotted of the eight-pole lpc vocoder and mvelpc vocoder that is based on a pre-emphasis filter as shown in figure (4). also, at the same figure and take 512 fast fourier transform (512-fft), the power spectral density (psd) of the original speech signal is determined and plotted. as can be seen from figure (4), the spectrum of eight-pole mvelpc vocoder is good at peaks and troughs. the first, second, third, fourth and fifth peaks are good for fitting the original speech. however, the spectrum of eight-pole lpc vocoder shows poor performance for fitting the original speech at the peaks and troughs. figure (5) illustrates the original speech signal with the reconstructed one for frame number 20 that is selected from wave file (ahmed.wav). the reconstructed one is shown to be very close and at most match the original signal. 5. conclusion in this paper, we presented a modified model vocoder that is based on voice-excited lpc to compress 2 male speech signals while maintaining low bit rate. the results have been achieved from the mvelpc are intelligible and desirable since the coder almost keeps perceptual relevant spectral characteristics of the speech signal. also, high segpsnr and low mse gained compared with the values obtained from classic lpc. the tradeoffs between speech quality on one side and bandwidth, the bit rate and complexity on the other side have analyzed and clearly appeared here. a better quality can be achieved by increasing the bit rate through an increase in bits used to quantize the dct coefficients, causing larger bandwidth have to be used as shown in table (2) and (3). on the other hand, the classic lpc results are much poorer, and they are unintelligible and ineligible. due to the fact that the mvelpc vocoder used gives pretty good results with the entire required limitations, particularly bit rate, the model can be more studied and improved. references [1] awwab q. althahab, 2013 "performance analysis of adaptive blind equalization algorithms for noisy fir and iir channels" m.s. thesis, university of colorado. [2] carlo magi, jouni pohjalainen, tom backstrom and paavo. alku, 2009 "stabilized weighted linear prediction" speech processing, vol. 51, no. 5, pp. 401-411. [3] colin breithaupt and rainer martin, 2011 "analysis of the decision-directed snr estimator for speech enhancement with respect to low-snr and transient conditions" ieee transactions on audio, speech and language processing, vol. 19, no. 2, pp. 277-289. [4] daniele giacobello, et al, 2014 "stable 1-norm error minimization based linear predictors for speech modeling" ieee transactions on audio, speech and language processing, vol. 22, no. 5, pp. 912-922. [5] george cybenko, 1980 "the numerical stability of the levinson-durbin algorithm for toeplitz systems of equations" siam j. sci. and stat. comput., vol. 1, issue 3, pp. 303-319. [6] jingyun xu, xiaoqun zhao, qiao wang and digang wang, 2014 "linear prediction analysis of speech signal based on norm" journal of computational information systems, vol. 10, no. 17, pp. 7553-7560. al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 [7] john makhoul, 1975 "linear prediction: a tutorial review" proc. ieee, vol. 63, no. 4, pp. 561-580. [8] john r. deller, john g. proakis and john h. l. hansen, 1999 "discrete-time processing of speech signals" wiley-ieee press. [9] lawrence rabiner and ronald w. schafer, 2009 "theory and application of digital speech processing" prentice-hall inc. [10] marcelo s. alencar and valdemar c. da rocha jr, 2005 "communication systems" springer. [11] minal mulye and sonal k. jagtap, 2014 "speech compression using analysis by synthesis" ijecce., vol. 5, issue 4, pp. 275-280. [12] stephen boyd and lieven vandenberghe, 2004 "convex optimization" cambridge university press. [13] thomas drugman and abeer alwan, 2011 "joint robust voicing detection and pitch estimation based on residual harmonics" proc. interspeech, pp. 1973-1976. [14] yi hu and philipos c. loizou, 2008 ''evaluation of objective quality measures for speech enhancement'' ieee trans. on speech, audio and language processing, vol. 16, no. 1, pp. 229-238. [15] yugandhar dasari and k. satyapriya, 2013 "performance analysis of speech coding techniques" ijareeie., vol. 2, issue 11, pp. 5725-5732. table (1): bit rate calculation for the proposed model including dct. parameters number of bits for each frame predictor coefficients=8 8*8=64 bits number of dct coefficients=30 30*(number of bits in quantizing process of residual error) gain of the predictor 5 bits total number of bits for each frame ? https://www.google.iq/search?hl=ar&tbo=p&tbm=bks&q=inauthor:%22john+r.+deller%22 https://www.google.iq/search?hl=ar&tbo=p&tbm=bks&q=inauthor:%22john+g.+proakis%22 https://www.google.iq/search?hl=ar&tbo=p&tbm=bks&q=inauthor:%22john+h.+l.+hansen%22 al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 566 table (2): simulation results for speech file (ahmed.wav). type of vocoder no. of predictor coefficients no. of bits in quantization process of residual error segpsnr in db mse bit rate based on table (1) (bits/sec) modified version of velpc with 30 dct coefficients 8 4 2.9403 0.0141 9450 8 6 4.1106 0.0084 12450 8 8 5.0021 0.0077 15450 velpc 8 --10.8479 0.0026 195450 classic lpc 8 --1.2687 0.1159 3800 table (3): simulation results for speech file (ali.wav). type of vocoder no. of predictor coefficients no. of bits in quantization process of residual error segpsnr in db mse bit rate based on table(1) (bits/sec) modified version of velpc with 30 dct coefficients 8 4 2.2512 0.0164 9450 8 6 4.1547 0.0081 12450 8 8 5.0952 0.0074 15450 velpc 8 --12.6146 0.0014 195450 classic lpc 8 --1.2266 0.1564 3800 voiced ( ) ( ) unvoiced speech signal figure (1): simple speech production system periodic impulse train random white noise ( ) al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 0 1 2 3 4 5 x 10 4 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 sample number a m p li tu d e the first original speech sound for (ahmed.wav) 0 1 2 3 4 5 x 10 4 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 sample number a m p li tu d e the mvelpc, reconstructed speech with 4 bits quantizing process 0 1 2 3 4 5 x 10 4 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 sample number a m p li tu d e the mvelpc, reconstructed speech with 6 bits quantizing process 0 1 2 3 4 5 x 10 4 -1 -0.5 0 0.5 1 sample number a m p li tu d e the mvelpc, reconstructed speech with 8 bits quantizing process ( ) ( ) channel figure (2): a voice-excited lpc system. figure (3): waveform of the sentence "welcome to the university of babylon", the original and reconstructed speech signals. lpc analyzer coder lpc synthesizer excitation detector decoder al-qadisiyah journal for engineering sciences, vol. 8……no. 4 ….2015 565 50 100 150 200 250 300 350 400 450 -4 -2 0 2 4 input signal and error signal( frame : 20 ) samples [ n ] a m p li tu d e input signal input signal*hamming error signal 0 1000 2000 3000 4000 5000 6000 7000 8000 -80 -60 -40 -20 0 fft of input signal, frequency reponse of lpc and mvelpc vocoder ( frame : 20 ) frequency [hz ] a m p li tu d e [ d b ] fft(fftpoints:512) mvelp vocoder(order:8) lpc vocoder(order:8) 0.475 0.48 0.485 0.49 0.495 0.5 -1.5 -1 -0.5 0 0.5 1 1.5 2 reconstructed signal and input signal ( frame : 20 of ahmed.wav ) time [ s ] a m p li tu d e signal reconstructed input signal figure (4): psd of input speech, frequency response of lpc and mvelpc vocoder. figure (5): original and reconstructed speech signal (frame no. 20 of ahmed.wav). article al-qadisiyah journal for engineering sciences 12 (2019) 105–111 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ahmidkadhim@yahoo.com (ahmed abed al-kadhem majhool ) https://doi.org/10.30772/qjes.v12i2.602 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. visualization and analysis studies of hollow cone spray under low air cross flow velocity under atmospheric condition ban k. abed jabar a and ahmed majho jabar a* a faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 20 june 2019 received in revised form 16 july 2019 accepted 18 july 2019 keywords: spray measurement low injection spray low cross flow velocity drop size distribution a b s t r a c t this study deals with the atomization of hollow cone spray water with low air cross flow. the visualization of the hollow cone spray by shadowgraphy, from the nozzle exit. the diameter of the nozzle allows observing different modes of breakup and structures (ligaments, helices, ...). the treatment of these images makes it possible to determine the drop size distribution of the spray droplets in function of length scales of the downstream flow. in the measurements of water hollow cone spray with injection pressures of 25kpa and air velocity of 10 m/sec. the calculations at the exit of the injector, in two planes perpendicular, and the average droplet sizes in the presence of air low cross flow conditions. the highspeed imaging is used to capture the final spray. these images are analyzed by using the image software. the structure and characteristics of the whole and sectional body of the spray are investigated at different times. the results show the droplet trajectory profile of the liquid droplets is in a good an agreement with analytical solution. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the hollow cone spray in cross flow is a very simplified configuration of a fluid, usually, fuel in liquid or gaseous form injected into a cross flow. it was in the 1930s that the first studies on jet in cross flow appeared. their purpose is to evaluate the dispersion, but also the consequences on the environment of the spray dispersion from the injector. since then, many works are related to the study of the hollow cone spray in cross flow and present the different characteristics of the spray cross flow. most of them relate to the trajectories and increases in the velocity of the main flow and the average behavior of velocity fields. in chul lee et al [1] used the spray jet penetration and drop size distribution to study experimentally the of liquid jets in subsonic cross-flows. david sedarsky et al [2] had been used the image processing technique located in the far field to investigate the breakup of a liquid jet in cross flow. they observed by using particle imaging measurements (piv). sudeepta mondal et al [3] improvement of the mixing process in a jet cross flow configuration in a confined environment is one of the primary objectives. the use of methods such as changing the shape of the injection port (section orifices squares, ovals, etc), the addition of a triangular protuberance or the rotation of the flow of the jet would increase the mixture significantly. schadow et al [4] studied the influence of a jet cross flow with triangular section, the injection being performed at the corners, and compared the levels of pressure fluctuations with a jet with a circular section. they found the formation of coherent structures circular section, while small-scale turbulence is generated at corners of the triangular injection. the amplitude of the fluctuations is then estimated at 10% of the average pressure while it amounts to more than 30% for the circular injection. surya et al [5], studied the influence of http://qu.edu.iq/ https://doi.org/10.30772/qjes.v00i0 106 ban k. abed jabar and ahmed majho jabar /al-qadisiyah journal for engineering sciences 12 (2019) 105–111 nomenclature y mass fraction. st strouhal number. d liquid jet diameter(m). greek symbols q liquid to air momentum-flux ratio. 𝜌 density kg/𝑚3. we weber number. 𝜎 surface tension n/m. fluid jet injection entrance environments on the construction of liquid jet in cross-flow. the momentum ratio of the liquid to air is directed in a range (q~3 − 100) and the weber number in a range (we = 17 − 89). highspeed imaging and shadowgraphy and highspeed imaging are utilized to investigate the drop size and the trajectory of the consequence spray. anubhav sinha et al [6], investigated exploratory examinations on the structure of air-blast spray. the atomizer is at a higher weight than encompassing and the air-blast gas is required to display includes commonly found in under-extended gas planes. they used proper orthogonal decomposition (pod) for the examination has been done utilizing these pictures. y.h. zhu et al[7], investigated the primary separation of a beat fluid stream in supersonic cross-flow is numerically researched. a two-stage stream 𝑳arge eddy simulation (les) calculation is created for reproductions of fluid fly atomization in a supersonic gas stream. zhanbo si et al [8], investigated the effects of cross-flow and flat divider impingement on the shower advancement and scattering. the spray was infused by 𝒂 valve covered orifice (vco) nozzle under different crossflow speeds and surrounding weights. a. rajabia et al [9], examined an ethanol fluid jet exposed to mix of an air cross-flow and a typical electric field. the fluid stream direction was found as a component of two nondimensional amounts; the fluid stream to the cross-flow force proportion and the electroinertial number. the electroinertial numbers defined as the proportion between the fluid fly specific energy and electric power. su and mungal[10], evaluated the scalar concentrations for two cross flow streams: one classic, the other protuberant. they then estimated the lengths of penetration and the jet openings. they show that adding a triangular protrusion inside the outflow of the jet implies a better efficiency of the mixture. liscinsky et al. [11] protuberances do not generate significant vorticity factitious compared to that caused by a transverse flow. in addition, they observe the penetration of the jet decreases with the increase in the number of swirls. there are many studies referring to jets not perpendicular to the flow principal, that is, inclined relative to the normal to the main flow. the jets forced are the subject of many investigations. therefore, the present paper. had as an objective to evaluate spray trajectory, the drop size distribution and spray intensity over the whole and three zones of spray liquid injected into low air cross flow velocity. past investigations of fluid injection in crossflow incorporate examinations of liquid atomized at various conditions. one of the key purposes of these examinations is the investigation of the spray dispersion. because of the way that cross stream fuel infusion is broadly utilized in gas turbine combustors, it is imperative to comprehend the components that control the spray separation, penetration, and transmission inside the cross stream. generally , the effectiveness of a spray in a cross flow is identified with its scattering in the flow. a comprehension of spray conduct in cross flow is essential for an effective control of the spray. spray structures in the bead system have for the most part been examined as far as spray infiltration .schetz et al [12] played out an energy examination on greatest infiltration height and found that the most extreme penetration tallness is the separation required to divert the fluid jet infusion momentum fluctuation to the air stream course. inamura et al[13] examined the widths spray, they utilized a photographic strategy and recorded pictures from the highest point of the spray field. a connection of spray widths was observed to be a component of q and x/d. .schetz et al [12] utilized a minuscule photography technique to quantify bead sizes for injectors of different geometries. the injector geometry was found to significantly affect the normal bead estimate. past research examinations that are relevant to the issue are those on spray in still air. ghosh et al [14], in their analysis described how the prompted air flows in spray planes have numerous likenesses with the air flow in tempestuous jets, and can be examined utilizing ideas and models first proposed by morton, et al [15]. the present tests measure the adjustments in splash structure with a uniform cross-stream speed of 10 m/s. previous estimations [16,17], have demonstrated that cross-stream because of tumble might be up to 25 m/s right off the bat in the acceptance stroke and between 5 and 10 m/s. late in the pressure stroke. the fire structure continues as before with elective infusion lengths for the period over which the valve is completely open [18]. 2. experimental facility and methods in this section, the apparatus that are used to characterize the single hollow cone spray in cross flow is presented. fig. 1. shows the schematic diagram of hollow cone spray visualization setup of equipment first, the general characteristics of the hollow cone spray in cross flow are provided: the average representation of a spray trajectories based on velocity and scalar, the length of penetration or the rate of flow of the spray constitute the spray intensity in this study. then an analysis of the unsteady aspect is invested. the main structure of spray drop size distribution is highlighted in many works and presented; the dynamics of the hollow cone spray is highlighted and the frequencies of passage structures are evaluated. all these results come from times of experiences.the injector is a prototype for hollow cone spray for water injection. this is an injector ”single hole” with a diameter of 1mm. the needle lift is controlled by mechanical ring system. the most likely source of error comes directly from the capacity of the injector produce repeatable data. the use of an injection system brings its share of variability. since he is turbulent flow, a series of successive streams can not be exactly the same. fig. 2. shows the water hollow cone spray injector used in the tests. in order to quantify this source of error, a series of tests were carried out. the test consisted of hollow cone spray (p inj = 25kpa, v gas = 10 m/sec) repeatedly and observe the trajectory curve. in total, three trials are conducted. this repeatability test is not presented, which puts into question the relevance of the data. although the number of tests performed in the present case seems little, the result of this exercise will come, at a minimum, to quantify the existence of an experimental variation in the tests. it presents the curves of the repeatability test. the low number of repeatability tests is due to a break in the high speed camera at the end of the experiments. the images are acquired by a digital ccd camera with fast shutter (casio exilim 1280 * 1084 12 bits, 8 hz), allowing fast double ban k. abed jabar and ahmed majho jabar /al-qadisiyah journal for engineering sciences 12 (2019) 105–111 107 exposure. this camera presents sensitivity and dynamics well suited to piv acquisitions. a pc is needed to control the operation of the light source and the camera. fig. 3. shows the ccd intense image camera with an ultrazoom lens. the installation of this experimental device makes it possible to obtain the velocity field of the gas phase around the spray for the study of training. visualization of the phase spray liquid is also achieved by using this camera. figure 1: schematic diagram of hollow cone spray visualization setup. figure 2: zoomed image of hollow cone nozzle. figure 3: zoomed image of camera observation direction. 3. results and discussion 3.1. experiment validation the characterization of the trajectory of the hollow cone spray has been the subject of much research and publications. as part of this study, it will limit to those carried out for the case of a low injection liquid spray, opening transversely into a low air cross flow uniform velocity. fig. 4. shows a comparison between the experimental result and the analytical method used by in chul lee et al., [19] where the influence of parameter q (momentum ratio) on the spray trajectory length. 𝑌 𝑑 = 𝑞0.75𝑊𝑒 −0.07 exp ( 0.057 𝑆𝑡 + 0.036 ) (1) where we is weber number and st is strouhal number is taken to be zero because it represents oscillating flow mechanisms 𝑊𝑒 = 𝜌𝑣𝑢 𝜎 (2) the agreement is good because in general, the parameter (𝑊𝑒) has a great direct influence on the trajectory of the spray, however, according to its range of values, it defines the primary atomization regime of the spray. but in each different atomization regime, the deformation of the spray is not the same, which has an influence on its trajectory. figure 4: comparison of predicted spray trajectory with the experimental data. 3.2. whole body structure the height represents the percentage of spray droplets that are in this range, for an unpressurized discharge of spray injection water. normally the type of graph representing the size distribution of droplets gives a graph like the one of contentious distribution. through the characterization of hollow cone spray according to the intrinsic structure. in the cross flow system, all experimental work is carried out on the average structure of the spray in a cross flow through concentration measurements. the gas velocity is constant. the four cases obtained are shown in fig. 6. at different time. the time interval among them is (5 sec). the spray droplets have only a main trajectory in the cross flow (fig. 6 a and b). moreover, with the increase of time, the jet tends to align horizontally in the cross flow as shown in fig. 6d. this phenomenon is related to the predominant momentum of the spray compared to that of the main flow. they identify the streams with single and multiple trajectories. the transition between these four types of spray trajectories is defined with the increase for dispersion as shown below. 108 ban k. abed jabar and ahmed majho jabar /al-qadisiyah journal for engineering sciences 12 (2019) 105–111 figure 5: histogram of droplet size at the air flow velocity of 10 m/sec at different time. figure 6: histogram of droplet size at the air flow velocity of 10 m/sec at different time. from image processing software which is used here to show droplets dispersion. spray dispersion in the sense used here of mixing the droplets with them and the surrounding gas. the gas phase velocity can be reached on the one hand via the relative velocity of the droplets. the dispersion of the hollow cone spray, in contrast to a translation of the spray, requires here, that different droplet sizes that have different relative velocities to the gas phase. fig. 7. shows the atomization process at a different time. fig. 7a shows the relative speed may be at an entry velocity, approximately lower than other cases due to the injection process at the earlier interval. that is maybe increased in fig. 7b based on spin-induced centrifugal forces. on the other hand the spray dispersion also occurs turbulence, if the droplets are light enough to follow the turbulent vortex movements of the gas as shown in fig. 7c and d due to gas interment. figure 7: hollow cone spray atomization mechanisms in microscopic view at different time. the visualization of the hollow cone spray at the outlet of the injector is done through the method of shadow. the resulting images are then processed numerically. in order to extract the parameters interesting characterizing the hollow cone spray, the images must be of good quality. the saturation of an image is the most important aspect of its quality. the images taken by transmission are subjected to two possible saturations, in the light, and in the dark. saturation in the clear is due to strong light power and the one in the dark is caused by opacity and the size of the photographed motif. a saturated image is losing information, so it is necessary to evaluate this aspect according to the light intensity of the source as well as the size of the photographed motif. fig. 8. shows the hollow cone spray intensity along its trajectory at different times. for this the light intensity of 66% of the power is chosen in order to quantify the saturation of the bright pixels. the work is done on the images of the records of the test pattern taken with a resolution of 3.45 m / pixel. in a hollow cone spray configuration, the injection is performed by means of a liquid sheet annular, sheared between two layers with fast moving gas cross-flows. fig. 9. shows surface area distribution of the two sheets at different times in such injection of the liquid, as well as the associated with atomization processes. in fig. 9a and b show, the mechanism of instability of the hollow cone spray sheared with air cross flow, which is apparent clearly. while at fig. 9 c and d this is no longer appeared due to the wide dispersion of droplets with time. (a) (b) ban k. abed jabar and ahmed majho jabar /al-qadisiyah journal for engineering sciences 12 (2019) 105–111 109 figure 8: hollow cone spray intensity along the traveling distance at different time. figure 9: three-dimensional surface of hollow cone spray at different time. 3.3. sectional body structure fig. 10 shows the results obtained for three sections where the positions are considered in fig.10 . it’s noted from that, the value of the spray intensity increases with the number of droplets as shown in fig.10c, but also presents a more pronounced more oscillatory behavior than the other two cases. fig. 11 shows a histogram of hollow cone spray at different sections. the distribution of total diameters of the drops of the spray obtained by the sectional procedure for measuring regimes 1,2 and 3 are compared in figure. as expected, it can be seen that the droplets measured for one injection condition may have very large diameters as shown in fig.12a. the droplets of small sizes nevertheless seem large differences as shown in fig. 12b and c. these values, corresponding to the position the peak of each distribution, appear relatively insensitive to the experiment. it is still quite surprising to find that the most observed for the highest zone (fig. 12a) where the two spray sheets are meeting. figure 10: hollow cone spray images of macroscopic spray shape with selected regimes. a b c d a b d c (a) (b) (c) 110 ban k. abed jabar and ahmed majho jabar /al-qadisiyah journal for engineering sciences 12 (2019) 105–111 figure 11: spray intensity along the traveling distance for different regimes. (a) (b) (c) figure 12: histogram of droplet size at different sections. a b c d ban k. abed jabar and ahmed majho jabar /al-qadisiyah journal for engineering sciences 12 (2019) 105–111 111 4. conclusion spray direction and droplet flight ways of a straightforward jet subject to mixes of cross flow and typical electric power were examined experimentally. the information of the present examination concurs well with the recently estimated information. the infiltration information is reliable, which is consoling thinking about the reality, that the nozzle configuration was marginally unique and extensive contrasts of the fly conduct with little structure. the droplet size and spray intensity are discussed, the distribution of the droplet diameter for all cases are considered. a histogram for all the spray pictures is taken by utilizing the picture handling. the estimation of droplet widths for the utilized range fundamentally relies upon the speed and so: the higher the estimations of speed the littler the droplet distance across. the impact of the liquid momentum transition on the droplet distance across is minimal. references 1. lee, i.c., et al., spray jet penetration and distribution of modulated liquid jets in subsonic cross-flows. journal of mechanical science and technology, 2010. 24(7): p. 1425-1431. 2. sedarsky, d., et al., model validation image data for breakup of a liquid jet in crossflow: part i. experiments in fluids, 2010. 49(2): p. 391-408. 3. mondal, s. and a. mukhopadhyay. numerical simulation of inclined injection of polydisperse polykinetic spray in a crossflow using quadrature method of moments. in asme 2014 gas turbine india conference. 2014. american society of mechanical engineers. 4. schadow, k.c., gutmark e., parr, d.m., parr, t.p., wilson, k.j., and ferrell, g.b., “enhancement of fine scale turbulence for improving fuel rich plume combustion,” journal of propulsion and power ,1990,vol 6 num,4,pp.357-363. 5. r. surya prakash, anubhav sinha, gaurav tomar, r.v. ravikrishna. liquid jet in crossflow – effect of liquid entry conditions. experimental thermal and fluid science 93(2018) 45-56. 6. anubhav sinha and rv ravikrishna. experimental studies on structure of airblast spray in crossflow. india academy of science.6 march 2019. 7. y.h. zhu, f. xiao, q.l. li, r. mo, c. li, s. lin. les of primary breakup of pulsed liquid jet in supersonic crossflow. science and technology on scramjet laboratory, national university of defense technology .27 october 2018. 8. zhanbo sia, nagisa shimasakia, keiya nishidaa, youichi ogataa, min guob, chenglong tangc, zuohua huangc. experimental study on impingement spray and near-field spray characteristics under highpressure cross-flow conditions. fuel218(2018) 12-22. 9. a. rajabi, m.r. morad, n. rahbari, s.r. pejman sereshkeh, m. razavi . liquid jet trajectory and droplet path influenced by combined cross flow and electric fields . department of aerospace engineering, sharif university of technology, tehran, iran. february 2, 2018. 10. l. su, m. mungal, simultaneous measurements of scalar and velocity field evolution in turbulent crossflowing jets, journal of fluid mechanics 513 (1) (2004) 1–45. 11. sccd.s. liscinsky, b. true, experimental investigation of crossflow jet mixing in a rectangulat duct, aiaa paper 93-2037 . 12. schetz, j.a and padhye,a.,"penteration and breakup of liquid in subsonic air streams, aiaa journal, vol.15,no.10,1977,pp.13851390. 13.inamura,t.,nagai,n.,watanabe, t., and yatsuyanagi,n.,"disintegration of liquid and slurryjets traversing subsonicair streams,"proceeding soft the 3rd world conference on experimental heat transfer, fluid mechanics and thermodynamics(honolulu,hl), elsevier, newyork, 1993,pp.1522-1529. 14. ghosh, s.& hunt, j.c.r.1994 induced air velocity in droplet-driven sprays. proc. r.soc. lond.a 444,105-127. 15. morton, b. r., taylor, g.i. & turner,j.s.1956) turbulent gravitational convection from maintained and instantaneous sources. proc. r. soc. lond. a234, 1-23. 16. a. m. k. p. taylor, y. hardalupas, j. h. whitelaw , k. ishii, h. miyano, y. urata, the effect of injector and intake port design on in-cylinder fuel droplet distribution , airflow and lean-burn performance of a honda vtec-e engine, sae paper 961923, 1996. 17. y. yan, s. gashi, j. m. nouri, r. d. lockett and c. arcoumanis, investigation of spray characteristics in a spray guided disi engine using plif and ldv, 2nd int. conference on optical diagnostics, icold, london, september 2005 18. a. m. k. p. taylor, y. hardalupas, j. h. whitelaw, k. ishii, h. miyano, y. urata, influence of injection timing on in-cylinder fuel distribution in a honda vtec-e engine, sae paper950507, 1995. 19. lee, in chul kang, young su moon, hee jang jang, seok pi. spray jet penetration and distribution of modulated liquid jets in subsonic crossflows. journal of mechanical science and technology. 2010. 14251431. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 78 numerical simulation of natural convection in an oblique enclosure filled with silver –water nanofluid mr. farooq hassan ali college of engineering-mechanical engineering department babylon university babylon city – hilla – iraq. email: farooq_hassan77@ yahoo.com received 22 september 2015 accepted 9 november 2015 abstract in this work, a numerical simulation of natural convection in an oblique enclosure filled with silverwater nanofluid is obtained for different values of rayleigh numbers, volume fraction and inclination angle of sloping walls. the considered oblique enclosure with left and right side walls are maintained at constant cold temperature (tc). the horizontal top wall of enclosure is kept insulated, but the bottom is maintained at constant hot temperature (th). the present work is utilized to obtain results in the range of rayleigh number (10 3 -10 6 ) , volume fraction of nanofluid varied from (0-0.2) and inclination angle of side walls are (-60 o , -30 o , 0 o , 30 o , 60 o ). the prandtle number is 6.0. the governing equations in the two-dimensional are solved numerically by using finite-difference technique. comparisons with other works are performed and the results are found to be in good agreement. the obtained results are shown in the form of stream function, isothermal lines and average nusselt numbers. it observed from results that acute shaping wall and ag-nanoparticles with high concentration are effective to enhance the rate of heat transfer, also; the average nusselt number for all range of inclination angle increases with increase in the rayleigh number and the solid volume fraction of the nanofluid. keywords: natural convection, oblique enclosure, nanofluid, rayleigh number النانوي الفضة بمائع مملوء مائل حيز في الحر للحمل ةالعددي النمذجة علي حسن فاروق م. الخالصة. تمت دراسة الحمل الحر في حيز مائل يحتوي على مائع الفضة النانوي لقيم مختلفة من ارقام رالي، الحجم الجزئي، زاوية ميالن الجانبية المائلة االيمن وااليسر للحيز عند درجة حرارة باردة. الجدار االفقي االعلى اعتبر معزوال، بينماالجدار. اعتبرت الجدران 10)درجة حرارة ساخنة. كان رقم رالي يتراوح بين)كان الجدار االفقي االسفل عند 6 -10 3 ، بينما تراوح الحجم الجزئي بين 60)بين )وتراوحت زاوية ميالن الجدران الجانبية 0.2-0)) o , 30 o , 0 o , -30 o , -60 o تم حل 6.0.وكان رقم برانتل يساوي . المعادالت الحاكمة لبعدين عدديا باستخدام تقنية الفروقات المحددة. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 77 مع بحوث سابقة واظهرت النتائج تطابق جيد. مثلت نتائج هذه الظاهرة بدالة الجريان، خطوط الحرارة وارقام المقارنةجرت نسلت. لقد لوحظ من النتائج ان للزوايا الحادة للجدار واضافة مائع النانوي بتراكيز عالية االثر الكبير في تعزيز انتقال الحرارة، بزيادة رقم رالي وكذلك زيادة تركيز المائع النانوي.الميالن يزداد كذلك ان متوسط رقم نسلت لجميع زوايا nomenclature: symbol description unit cp specific heat kj/kg.k g gravitational acceleration m/s 2 h height of the parallelogram cavity m k thermal conductivity of fluid w/m.k n outward flux normal to boundary nu average nusselt number p dimensionless pressure p pressure pr= /  prandtl number ra= gql 5 / k rayleigh number s nondimensional length along inclined heated surface t temperature k tc temperature of the cold surface k th temperature of the hot surface °c u velocity component in x-direction m/s u dimensionless velocity component in x-direction v velocity component in y-direction m/s v dimensionless velocity component in y-direction x cartesian coordinate in horizontal direction m x dimensionless cartesian coordinate in horizontal direction y cartesian coordinate in vertical direction m y dimensionless cartesian coordinate in vertical direction greek symbols  thermal diffusivity m 2 /s  volumetric coefficient of thermal expansion k -1 θ dimensionless temperature μ dynamic viscosity of the fluid n.s/m 2 φ nanoparticles volume fraction ϑ kinematic viscosity of the fluid m 2 /s ρ density of the fluid kg/m 3 φ sidewall inclination angle from vertical deg ψ dimensionless stream function al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 78 ψ stream function m 2 /s subscripts c cold f fluid (pure) nf nanofluid h hot s solid (nanoparticale) l left sidewall r right sidewall abbreviation fig figure fdm finite difference method min minimum max maximum 1introduction in the last decade, a computational as well as experimental researches have analyzed the natural convection heat transfer phenomena with addition of fluid suspension of nano metric solid particles or fibers to the liquids. these addition effect on the performance of the heat of the liquids. the steady state natural convection heat transfer characteristics in a differentially heated square enclosure filled with different types of nanofluids for different published variables have been investigated in the literature [1-5]. moreover, the unsteady state natural convection heat transfer of water-al2o3 nano fluid in differentially heated square enclosure too, is studied numerically by t. a. al-hattab [6] using a finite element method. also, for the above-mentioned diversity among the numerical predictions but the work of y. varol et. al. [7] and c. j. ho et. al. [8], an experimental studies have been undertaken concerning natural convection heat transfer efficacy of using nanofluids in an enclosures. in the recent years, the lattice boltzmann simulation were applied to investigate the natural convection flow utilizing nan fluid. fattahi et. al. [9] and gh. r kefayati et. al.[10] applied the lattice boltzmann method to investigate the natural convection flow utilizing al2o3 or cu-water, and sio2-water nanofluids respectively, in a square cavities. the results indicates that by increasing volume fraction, the average nusselt numbers increase for all used nanofluids. as well as the same results of average nusselt numbers were obtained by gh. r. kefayti et. al. [11] investigation by using lattice boltzmann simulation of natural convection in an open enclosure which subjected to cu-water nanofluid. in addition a lattice boltzmann model is developed by y. he. et. al. [12] by coupling the density and the temperature distribution to simulate the convection heat transfer utilizing al2o3-water nanofluids in a square cavity. inclination angle and sinusoidal heating or cooling can be a control parameters and percentage enhancement of heat transfer for nanofluid filled enclosure. hence h. f. oztop et. al. [13] and h. k. oztop et. al. [14], analyzed numerically the effect of inclination angle and a sinusoidal heating and cooling temperature profiles on one side, respectively, on natural convection heat transfer and fluid flow in a two-dimensional enclosure filled with nanofluid. also, e. b. ogut [15] investigate the natural convection heat transfer of water based in a nanofluid in inclined square enclosure where left vertical side is heated with a constant heat flux. the result show that the length of the heater is also important parameter affecting on the flow and temperature fields. a comparison studied were presented by s. m. aminosadti and b. ghasmi [16-18] and s. m. aminosadti and b. ghasmi [19] for multi cases of heat transfer in the nanofluid filled a square and triangular cavities respectively al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 89 with different arrangement and oscillation of the one or two heat source-sink on the walls of the cavities. the result show that the length, location, oscillation of the source and the shape of the cavity proved to significant design of an effective cooling system for electronic components to help ensure, effective and safe operation conditions. natural convection inside irregular and non-square enclosures has a wide applications in engineering and industry. investigation on natural convection in non-square enclosure with different geometries has been done by many researches. hence, the works of m. mohmoodi [2021] and h. saleh et. al. [22] focus on problems of free convection fluid and heat transfer of a nanofluid inside l-shaped and trapezoidal cavities, respectively. the obtained results for l-shaped enclosure show that the average nusselt number increases with increase in the rayleigh number for all range of enclosure aspect ratio. moreover, it is found that the rate of heat transfer increases with decreasing the aspect ratio of the enclosure. also, it was found for trapezoidal enclosure that acute shaping wall and cunanofluid with high concentration are effective to enhance the rate of heat transfer. six common enclosures shapes are investigated by o. abouali et. al. [23] to show that the internal natural convection of a single phase nanofluids in enclosures can be easily predicted theoretically with no need to perform a numerical solution. habibis et. al. [24] carried out a numerical investigation on heat transfer enhancement utilizing cu-water nanofluid in a parallelogrammic enclosure by finite difference method. the result show that increasing the base angle caused decreasing the heat transfer rate. finally, laminar natural convection of a copper-water nanofluid in differentially heated parallelogrammic enclosure has been studied numerically using the finite volume method by salam et. al. [26] the result show that the heat transfer rate increase remarkably by the addition of copperwater nanofluid and the shape of the convection vortices is sensitive to the skew angle variation. based on literature reviews, a little effort has been spent up to date to simulate the natural convection heat transfer in an oblique enclosures filled with nanoparticles. this problem may be happened in many applications such as cooling or heating of electronic device. in the present work the of natural convection heat transfer and fluid flow in oblique enclosure filled with silver-water nanofluid is investigated numerically using the finite difference method. the results are shown in the forms of streamlines, isotherms plots and average nusselt numbers for three walls, right, left and bottom, wide range of rayleigh numbers (10 3 -10 6 ) are presented and the effect of the oblique enclosure angles are considered also between (-60 o <φ<60 o ). 2governing equations and boundary conditions fig.1 shows a schematic configuration of the computational domain and coordinate system used in the present study. governing equations and boundary conditions of two-dimensional natural convection steady, laminar and incompressible of a silver-water inside oblique enclosure are describe below. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 89 the dimensionless forms of the governing equations (continuity, momentum and energy equations) for the present problem can be written as follows[13]: (1) ( ) (2) ( ) ( ) (3) ( ) (4) where ( ) thermal diffusivity, the effective density and heat capacity of nanofluids given as [13]: ( ) (5) ( ) (6) figure (1): schematic diagram and coordinate system of the physical domain with boundary conditions. φ x tc h tc adiabatic 𝒈 y w th al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 89 ( ) ( )( ) ( ) (7) furthermore, the effective thermal expansion coefficient ( ) and viscosity of nanofluid ( ) were introduced as below [13]: ( ) ( )( ) ( ) (8) ( ) (9) in addition, the effective thermal conductivity ( ) of nanofluid is approximated by the maxwell garnetss [25]: ( ) ( ) the fluid motion is displayed using the dimensionless stream function ( ) obtained from velocity components u and v. the relationships between stream function and velocity components for two dimensional flows are: (10) according to fig.1 the boundary conditions as applied in this present simulation are: at the left wall: u=0, v=0, t=tc at the right wall: u=0, v=0, t=tc at the top wall: u=0, v=0, at bottom wall: u=0, v=0, t=th the rate of heat transfer is represented in terms of average nusselt number at the side walls ( ̅̅̅̅ ) as follows: ̅̅̅̅ ∫ ( )[ ] (11) where s and n are the non-dimensional length and coordinate along the inclined walls respectively. 3numerical solution the discretization procedure of the governing equations is based on a finite difference technique. a non-uniform finite difference mesh with collocated variable locations is used for the computation. the set of governing equations are integrate over the finite differences, which produces a set of linear algebraic equations. the convection term are discretized using the second-order upwind scheme while the diffusion terms are discretized using the central difference scheme. the pressure al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 89 velocity coupling is treated using the well-known simplec method. the set algebraic equations for each variable are solved sequentially using an iterative method. the solution is considered converged when the normalized residual falls below 10 -6 for the energy equation and below 10 -4 for other variables. the stricter convergence limit for the energy equation is required to ensure global heat balance. to validate the numerical simulation, the results present work of natural convection in a square enclosure were compared with the previous published works of basak and chemka [4]. it is worth mentioning that the side walls are fixed at cold temperature (tc). the horizontal top wall is insulated but the bottom are fixed too at hot temperature (th). we use the same boundary conditions and wall temperatures on horizontal and vertical walls of the enclosure. streamlines and isotherms for different values of rayleigh number (ra= 10 3 and 10 5 ) are presented in fig.2. it can be seen from the figure that the present results and those reported by basak and chemka [4] are in excellent agreement. 4results and discussions the natural convection of silver-water nanofluid is investigated for various value of rayleigh numbers and volume fractions in oblique enclosure. the rayleigh number varied from (10 3 -10 6 ) and volume fraction from (0-0.2) while the oblique angle changed from (-60 o to 60 o ). water is the base fluid with pr=6.57 at 22 o c, containing ag nanoparticles. figs. (3&4) show the contours for the stream function and temperature respectively for ag-water nanofluid for different oblique angle (φ) and rayleigh number at volume fraction (φ=0) and (φ=0.15). this figures illustrates the effects of rayleigh number and side wall inclination angle for pure water (φ=0) and volume fraction (φ=0.15) nanofluid.fig.3 shows that when (φ=0) and (ra=10 3 ), symmetrical flow and temperature pattern are observed in enclosure since the symmetric boundary conditions along middle horizontal axis, two large recirculating eddies with ellipticalshaped core region are generated inside the enclosure as a result of cooling nanofluid along cold side walls and heating nanofluid parallel to the hot bottom wall. also seen from figure (3) with increase of rayleigh number from 10 4 to 10 6 , the flow pattern does not change significantly and the shape of the central region of eddies, which are ellipses, does not change. the value of stream function increases, more over the maximum stream function is seen toward the core region of the two eddies due to the increase of the heat transfer from hot bottom wall and fluid since velocity increase. the effect of change in inclination angles can be more clearly understood from contours plots (second and third columns), when (φ=30 o ) the right cell becomes more elongate and penetrates into acute corner of the enclosure, with increasing rayleigh number the right cell squeeze along the cold right wall and expand along the hot bottom wall and two small cells appears along the left side wall because the convective mode was dominated in the enclosure. for (φ=60 o ) two cells occupied the enclosure, with increase rayleigh number right cell becomes large in size while left cell becomes small in size because convective is dominated. in general, the effect of nanoparticles on the streamlines is clear when the value of the maximum stream function and stream lines motivation reduced for different rayleigh number, but no significant change in flow patterns is observed. fig.(4) show the temperature contours for ag-water nanofluid for different oblique angle (φ) and rayleigh number at volume fraction (φ=0) and (φ=0.15), when (φ=0 o ) thermal distribution reflect the conduction heat transfer mode. with increase in the rayleigh number, convection heat transfer becomes stronger. in addition, the temperature contours becomes more and more crowded near the cold side walls as rayleigh number increases, which explains that the heat transfer behaviors change from conduction to convection. it should be marked that the thermal boundary layer at the cold walls decreases as the inclination angle is increased and increases with the rayleigh number is increased. with the increment of the tilting angle, the isotherms near the left acute angle becomes proximate and rigorous plum formation as rayleigh number increased. since the increase in the al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 89 viscosity of the nanofluid with the increase the volume fraction, the diffusion of heat transfer is increased, therefore the crowded of temperature contours near the side walls decrease. fig. (5) illustrates the stream function for various values of ra= 10 3 , 10 4 , 10 5 and 10 6 and twice skew angles(-30 o ) and (-60 o ) at volume fraction φ=0.15. for pure water (dotty lines) and agnanofluid (solid lines). it is noticed at low rayleigh number the enclosure filled by two cells, left large cell and right small cell. this configuration appears since the distribution of boundary conditions and inclination angles. as expected due to the cold vertical walls, fluids rise up from middle portion of the bottom wall and flow down along the two vertical walls forming two unsymmetrical cells with clock and anti-clockwise direction inside the enclosure. at lower rayleigh number, the magnitude of stream function are considerably lower (ψmax=0.135 for φ=30o and ψmax=0.045 for φ=-60 o ) and conduction heat transfer mode was dominant. also it can be observed that the behavior of pure water and nanofluid are identical for the same reason. when rayleigh number increase this identical was vanished since the convection mode becomes dominant and velocity of fluid increasing. the difference in density between pure and nanofluid makes this dissimilarity in flow pattern between them. effect of negative inclination angle of the sloping walls on the thermal filed are presented in fig.6, for water-ag nanofluid with volume fraction (φ=0.15) and pure water with the range of rayleigh number (ra=10 3 -10 6 ). the isothermal lines are smooth curves with respect to the vertical lines, with increasing gradually and the advection takes the command, becoming the dominant mode of heat transfer. the circulation is greater near the center and least at the wall due to no slip boundary condition. it is observed from isothermal lines the nanofluid lines take the same habit as pure water at low rayleigh number but this habit vanish and interaction between isothermal lines of nanofluid and pure fluid take placed due to advection effect. the average mean nusselt number variation across left cold wall, right cold wall and bottom hot wall for different inclination angles and rayleigh values are shown from fig. (7) to fig. (11).five different volume fraction are used as φ=0, 0.05, 0.1, 0.15 and 0.2 . average nusselt number is calculated by integration of local nusselt number over walls surfaces as given in equation (12). for all figures subscript (a, b, c) refers to the average nusselt number over the left, right and bottom walls respectively. as given in the figures, average nusselt number are almost constant up to ra=10 4 due to quasi-conductive regime, after that they increasing with increasing rayleigh number as expected. for all values of volume fraction and skew angles the same trend are noticed. for each graph when compared with each other, it is seen that, nusselt number is increased with increasing of volume fraction due to increase the thermal conductivity of nanofluid which causes more heat transfer passes.fig.(12) shows profiles of the average nusselt number along the bottom heated wall versus the inclination angle for silver nanofluids at volume fraction (φ=0.2) and a range of rayleigh number (10 3 ≤ra≤10 6 ). symmetrical trends are noticed also the enhance heat transfer rate more evident at the parallelogram geometry (φ=60 o and -60 o ) than the square geometry (φ=0 o ). this is due to that at parallelogram geometry the inclination sidewalls have large surface area this lead to high heat transfer rate. 5conclusions in this numerical analysis the results of the study of natural convection in an oblique enclosure filled with silver-water nanofluid are presented using parameter of interest as rayleigh number, volume fraction and angle of inclination. in view of the obtained results, the following findings may be summarized: (1) average nusselt number becomes constant for the smaller value of rayleigh numbers due to domination of conductive regime. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 89 (2) it is observed that the volume fraction and skew angles are one of the most importance parameters on the flow fields, temperature fields and heat transfer. (3) increased volume fraction percentage, as expected, enhances the heat transfer due to increasing thermal conductivity as can observed in table (1). (4) peak values on average nusselt number distribution are observed on the hot bottom wall, with addition of the nanofluid and increasing rayleigh number when the angle of inclination equal (60 o , -60 o ). this is due to the high amount of flow velocity. (5) the flow intensity increases as the volume fraction and rayleigh number increases and reaches maximum at parallelogram shape (φ=60 o and -60 o ) and reaches minimum at square shape (φ=0 o ). references [1] ayad m. salman; an investigation of natural convection heat transfer in a square enclosure filled with nanofluid, eng. & tech. journal, vol.29, no.12 (2011) 2346-2363. [2] mehdi nikfar, mustafa mahmoodi; meshless local petrov-galerkin analysis of free convection of nanofluid in a cavity with wavy side walls, engineering analysis with boundary elements 36 (2012) 433-445. 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[22] h. sleh, r. roslan, i. hashim; natural convection heat transfer in a nanofluid-filled trapezoidal enclosure, international journal of heat and mass transfer 54 (2011) 194-201. [23] omid abouali, coodarz ahmadi; computer simulations of natural convection of single phase nanofluids enclosures: a critical review, applied thermal engineering 36 (2012) 1-13. [24] saleh, h., basriati, s., and hashim, i., solutions of natural convection of nanofluids in a parallelogrammic enclosure by finite difference method, j. mat. dan sains, 16(2)(2011), 77–81. [25] maxwell, j., 1904, a treatise on electricity and magnetism , 2nd ed., oxford university, cambridge. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 88 [26] salam h. hussain and ahmed k. hussein; natural convection heat transfer enhancement in a differentially heated parallelogrammic enclosure filled with copper-water nanofluid, asmejournal of heat transfer, 136 (2014) 1-8. 0.2 0.15 0.1 0.05 φ φ 42.7% 34.4% 24.9% 13.5% 60 o 42.6% 35.8% 24.8% 13.5% 30 o 42.6% 34.4% 24.8% 13.5% 0 o 42.6% 35.8% 24.8% 13.5% -30 0 42.7% 34.4% 24.9% 13.5% -60 o 0.2 0.15 0.1 0.05 φ φ 34.3% 27.4% 19.5% 10.4% 60 o 24.8% 18.9% 13.5% 7.6% 30 o 26.2% 21.1% 15.2% 8.3% 0 o 24.8% 18.9% 13.5% 7.6% -30 0 34.3% 27.4% 19.5% 10.4% -60 o table (1): represent increase in heat transfer rate for different inclination angle and volume fraction along bottom heated wall at ra=10 6 and 10 3 . ra=10 3 ra=10 6 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 87 b. benchmark problem [4] figure (2): comparison of temperature (θ) and stream function (ψ) contours for isothermally hot bottom and cold side walls of cu–water nanofluids with benchmark problem [4] for φ= 0.2 at (a) ra = 10 3 , (b) ra = 10 5 …..., water and —, nanofluid. b. present work a. present work a. benchmark problem [4] al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 88 figure (3): stream function (ψ) contours for isothermally hot bottom and cold side walls of ag–water nanofluids for different oblique angles (φ( and ra at φ= 0, …..., water and φ= 0.15,—,nanofluid. φ=0° φ=30° φ=60° r a = 1 0 3 r a = 1 0 4 r a = 1 0 5 r a = 1 0 6 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 999 figure (4): temperature (θ) contours for isothermally hot bottom and cold side walls of ag–water nanofluids for different oblique angles (φ( and ra at φ= 0, …..., water and φ= 0.15,—,nanofluid. φ=0° φ=30° φ=60° r a = 1 0 3 r a = 1 0 4 r a = 1 0 5 r a = 1 0 6 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 999 figure (5): stream function (ψ) contours for isothermally hot bottom and cold side walls of ag–water nanofluids for different oblique angles (φ( and ra at φ= 0, …..., water and φ= 0.15,—,nanofluid. φ=-30° φ=-60° r a = 1 0 3 r a = 1 0 4 r a = 1 0 5 r a = 1 0 6 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 999 figure (6): temperature (θ) contours for isothermally hot bottom and cold side walls of ag–water nanofluids for different oblique angles (φ( and ra at φ= 0, …..., water and φ= 0.15,—,nanofluid. φ=-30° r a = 1 0 3 r a = 1 0 4 r a = 1 0 5 φ=-60° r a = 1 0 6 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 999 figure (7): average mean nusselt numbers with rayleigh numbers at different values of volume fraction and (φ=0 o ) {(a)= left side wall, (b)= right side wall and (c)= bottom side wall} (c) 1000 10000 100000 1000000 ra 4 6 8 10 12 14 16 18 20 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% (b) 1000 10000 100000 1000000 ra 4 5 6 7 8 9 10 11 12 13 14 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% (a) (b) (c) figure (8): average mean nusselt numbers with rayleigh numbers at different values of volume fraction and (φ=30 o ) {(a)= left side wall, (b)= right side wall and (c)= bottom side wall} (a) 1000 10000 100000 1000000 ra 2 3 4 5 6 7 8 9 10 n u volume fraction % 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 2 3 4 5 6 7 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 6 8 10 12 14 16 18 20 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 2 3 4 5 6 7 8 9 10 n u volume fraction % 0% 0.05% 0.1% 0.15% 0.2% al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 999 1000 10000 100000 1000000 ra 1.5 2.0 2.5 3.0 3.5 4.0 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% (a) (c) (b) fig (9) average mean nusselt numbers with rayleigh numbers at different values of volume fraction and (φ=60 o ) {(a)= left side wall, (b)= right side wall and (c)= bottom side wall} (a) (b) (c) figure (10): average mean nusselt numbers with rayleigh numbers at different values of volume fraction and (φ=-60 o ) {(a)= left side wall, (b)= right side wall and (c)= bottom side wall} 1000 10000 100000 1000000 ra 10 12 14 16 18 20 22 24 26 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 10 12 14 16 18 20 22 24 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 1.5 2.0 2.5 3.0 3.5 4.0 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 10 12 14 16 18 20 22 24 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 10 12 14 16 18 20 22 24 26 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 999 1000 10000 100000 1000000 ra 4 5 6 7 8 9 10 11 12 13 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 2 3 4 5 6 7 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% 1000 10000 100000 1000000 ra 6 8 10 12 14 16 18 20 n u volume fraction% 0% 0.05% 0.1% 0.15% 0.2% (c) (a) (b) figure (11): average mean nusselt numbers with rayleigh numbers at different values of volume fraction and (φ=-30 o ) {(a)= left side wall, (b)= right side wall and (c)= bottom side wall} figure (12) average mean nusselt numbers with inclination angle at different values of rayleigh numbers and (φ=0.2( for bottom heated wall} -60 -30 0 30 60 inclination angle 0 5 10 15 20 25 30 n u ra=1000 ra=10000 ra=100000 ra=1000000 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 influences and optimization of cnc turning machining parameters shukry h. aghdeab baqer ayad ahmed production engineering and metallurgy bakeryd@yahoo.com department, university of technology/ baghdad shukry_hammed@yahoo.com mohammed sattar jabbar asaad ali abbas mohammedsattar43@yahoo.com asaad.ali.abbas@gmail.com received 26 october 2015 accepted 21 february 2016 abstract in this study, the objective is to obtain optimal values of cnc turning parameters (cutting speed, depth of cut and feed rate) which result in an optimal value of surface roughness by machining aluminum shaft. in this work, taguchi method was carried out on machining of aluminum enac43400 material in dry cutting using cnc turning machine type starchip 450 equip with carbide cutting tool type dnmg 332. surface roughness was measured using the pocket surf emd1500 tester. the results obtained of the surface roughness (ra) are about (1.14-1.91) μm, and the best was at cutting speed 250 m/min, feed rate 0.05 mm/rev and depth of cut 0.5 mm which is refers to the optimum machining parameters. keywords: cnc turning process, surface roughness, machining parameters, optimization, taguchi method. الخراطة المبرمجة ماكنةعلى التشغيلمحددات وأمثلية تأثير الخالصة الخراطة المبرمجة )سرعة القطع, عمق لماكنة التشغيل في هذه الدراسة, الهدف هو الحصول على القيم المثلى لمحددات . في هذا العمل, تم استخدام enac-43400القطع والتغذية( كنتيجة لقيم مثلى من الخشونة السطحية بتشغيل قضيب من األلمنيوم باستخدام عدة قطع كاربيدية نوع starchip 450الخراطة نوع ماكنةعملية تشغيل سبيكة األلمنيوم في فيطريقة تاكوجي dnmg 332 باستخدام تم قياسهاوالخشونة السطحيةpocket surf emd-1500 tester النتائج التي تم الحصول . متر/دقيقة ,وتغذية 250) سرعة القطع ضلها عندوافمايكرومتر, (1.91-1.14بحدود )كانت ( raخشونة السطحية )للعليها .تشير الى متغيرات التشغيل المثلىملم( والتي 0.5ملم/دورة، وعمق قطع 0.05 introduction a surface manufactured by cutting processes is one of the most important criteria for quality. surface roughness is a significant factor which is not only important for wear, friction and lubrication which became traditional for tribology, but also important for sealing, hydrodynamic, mailto:shukry_hammed@yahoo.com mailto:mohammedsattar43@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 electric and heat transfer. surface roughness depends on lots of variable such as material couple, manufacturing type, cutting conditions and etc. surface roughness is one of the most important characteristic variable to be monitored in the cutting processes owing to the direct relation between change of surface roughness and cutting conditions (ilhan, 2010). in machining operation, the surface finish is an important requirement of workpieces and parameter in manufacturing engineering. during the turning operation, the cutting tool and the metal bar are subjected to a prescribed deformation as a result of the relative motion between the tool and workpiece both in the cutting speed direction. as a response to the prescribed deformation, the tool is subjected to thermal loads on those faces that have interfacial contact with the workpiece or chip. in the metal-cutting process, during which chips are formed, the workpiece material is compressed and subjected to plastic deformation. usually the material removal occurs in a highly hostile environment with high temperature and pressure, in the cutting zone. the ultimate objective of the science of metal cutting is to solve practical problems associated with efficient material removal in the metal cutting process. to achieve this, the principle governing the cutting process should be understood. knowledge of this principle predicts the practical result of the cutting process and thus the select the optimum cutting conditions for each particular case (rakesh, 2012). the literature survey has revealed that several researchers attempted to calculate the optimal cutting conditions in turning operations. basim a. khidhir and bashir mohamed (2011) studied the effect of cutting speed, feed rate and depth of cut on surface roughness. the tests were performed on nickel based hastelloy c-276 using two different inserts of ceramic cutting tools. it has been found that the good surface roughness is obtain with higher cutting speed, minimum feed rate and lower depth of cut. anil gupta and et al (2010) studied the effect of cutting speed, feed rate, depth of cut, nose radius and cutting environment on surface roughness, tool life, cutting force and power consumption. it have been found that cutting speed of 160 m/min, nose radius of 0.8 mm, feed of 0.1 mm/rev, depth of cut of 0.2 mm and the cryogenic environment are the most favorable cutting parameters for high speed cnc turning of aisi p-20 too1 steel. ilhan asiltürk and mehmet çunkas (2011) studied the effect of cutting speed, feed rate, depth of cut on surface roughness of aisi 1040 steel. it have been implemented full factorial experimental design to increase the confidence limit and reliability of the experimental data, artificial neural networks (ann) and multiple regression approaches, it have been compare multiple regression and neural network using statistical methods. it has been found that the proposed models are capable of prediction of the surface roughness. the ann model estimates the surface roughness with high accuracy compared to the multiple regression model. attanasio and et al (2011) have been investigation a series of orthogonal hard turning tests were conducted to study the effects of tool wear and cutting parameters (cutting speed and feed rate), on white and dark layer formation in hardened aisi 52100 bearing steel. it has been found that the crater wear rate is influenced by both cutting speed and feed rate, while flank wear rate seemed to be mainly effected by cutting speed. also it was found that the thickness of white and dark layers increases with increasing of tool flank wear. moreover higher cutting speed generates thicker white layers and thinner dark layers. in addition, smaller feed rates moderately influence the white layers thickness, while the latter rises with higher feed rate. in contrast, the dark layers thickness decreases with the increasing of the feed rate, especially when flank wear values higher 0.075 mm were observed. ilhan asiltürk and süleyman neseli (2012) have been determine the effect of cutting parameters namely, cutting speed, depth of cut and feed rate on surface roughness during machining of aisi 304 austenitic stainless. the model for the surface roughness, as a function of cutting parameters, is al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 020 obtained using the response surface methodology (rsm). it have been found that the feed rate is the dominant factor affecting surface roughness, which is minimized when the feed rate and depth of cut are set to the lowest level, while the cutting speed is set to the highest level. the percentages of error all fall within 1%, between the predicted values and the experimental values. suleyman neseli and et al (2011) have been investigated the effect of tool geometry parameters on the surface roughness during turning of aisi 1040 steel. it has been developed prediction model related to average surface roughness (ra) using experimental data. it has been found that the tool nose radius was the dominant factor on the surface roughness with 51.45% contribution in the total variability of model. also, approach angle and rake angle are significant factors on surface roughness with 18.24% and 17.74% contribution in the total variability of model, respectively. in addition, a good agreement between the predicted and measured surface roughness was observed. h. k. dave and et al (2012) have been investigated the machining characteristics of different grades of en materials in cnc turning process using tin coated cutting tools. in this research focused on the analysis of optimum cutting conditions to get the lowest surface roughness and maximum material removal rate (mrr) in cnc turning of different grades of en materials by taguchi method. it have been found that anova shown that the depth of cut has significant role to play in producing higher mrr and insert has significant role to play for production lower surface roughness. thus, it is possible to increase machine utilization and decrease production cost in an automated manufacturing environment. were minimum surface roughness when machined by cn1500 tool at 150 m/min speed, 0.30 mm/rev feed and 1 mm depth of cut and maximum mrr when machined by cc8020 tool at 150 m/min speed, 0.30 mm/rev feed and 1.5 mm depth of cut. m. kaladhar and et al (2012) have been investing the effects of process parameters on surface finish and material removal rate (mrr) to obtain the optimal setting of these process parameters. and the analysis of variance (anova) is also used to analyze the influence of cutting parameters during machining. it have been found that the feed and nose radius is the most significant process parameters on workpiece surface roughness. however, the depth of cut and feed are the significant factors on mrr. optimal range and optimal level of parameters are also predicted for responses. the optimal combination of process parameters for minimum surface roughness is obtained at 150 m/min cutting speed, 0.25 mm/rev feed rate, 2 mm depth of cut and 0.4 mm nose radius. and the optimal combination of process parameters for maximum mrr is obtained at 170 m/min cutting speed, 0.3 mm/rev feed rate, 2mm depth of cut and 0.4mm/0.8mm nose radius. anderson p. paiva and et al (2007) have been conduct experiment on aisi 52100 hardened steel with different parameter (cutting speed, feed rate and depth of cut). the outputs considered were (the mixed ceramic tool life, processing cost per piece, cutting time, the total turning cycle time, surface roughness and material removal rate). the results indicate that the multi response optimization is achieved at a cutting speed of 238 m/min, with a feed rate of 0.08 mm/rev and at a depth of cut 0.32 mm. tian syung lan (2010) have been investigate the effect of cutting speed, feed rate, cutting depth and tool nose runoff with three levels (low, medium, high) mrr in finish turning based on fuzzy l9(34) orthogonal array. it have been found that the material removal rates from the fuzzy taguchi deduction optimization parameters are all significantly advanced comparing to those from the benchmark. also it has been declare that contributed the satisfactory fuzzy linguistic approach for the mrr in cnc turning with profound insight. it is observed that the mrr under fuzzy deduction parameters are significantly improved by 87.5, 150.0 and 212.5% from the benchmark parameters. hussam lefta alwan (2013) have been investigated the effect of machining conditions in turning of al-12%si alloy to get lowest surface roughness by applying the taguchi method. the percent contribution of the significant factor produced from analysis of variance anova is 53.14 %. this is, for this case study, the depth of cut has the highest contribution; therefore, the depth of cut is an al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 important factor to be taken into consideration during machining al-12%si alloy followed by feed rate, and cutting speed respectively. taguchi method traditional experimental design procedures are too complicated, very expensive and not easy to use. a large number of experimental works has to be carried out when the number of process parameters increases. to solve this problem, the taguchi method uses a special design of orthogonal arrays to study the entire parameter space with only a small number of experiments (małgorzata, 2014). taguchi method, widely utilized in engineering analysis, consists of a plan of experiments with the objective of acquiring data in a controlled way, in order to obtain information about the behavior of a given process. the greatest advantage of this method is the saving of effort in conducting experiments; saving experimental time, reducing the cost and discovering significant factors quickly (rama, 2012). taguchi design experiments using specially constructed tables known as “orthogonal array” (oa). the use of these tables makes the design of experiments very easy, consistent and required relatively lesser number of experimental trials to study the entire parameter space. as a result, time, cost, and labor saving can be achieved. the experimental results are transformed to signal -tonoise (s/n) ratio. taguchi recommends the use of the s/n ratio to measure the quality characteristics deviating from the desired values. usually, there are three categories of quality characteristic in the analysis of the s/n ratio, i.e. the-lower-the-better, thehigher-the-better and the nominal-the-better. the s/n ratio for each level of process parameters is computed based on the s/n analysis (p.g.kochure, 2012). the signal-noise [s/n] ratio is calculated from applying equations (raviraj, 2008): i) for the “smaller is better” the equation is: (1) ii) for the “larger is better” the equation is: where: s/n = the signal-noise ratio n= the number of observations yi = the observed data. for our study the "the smaller is better" was used because smaller values of surface roughness means high quality of machined surface. experimental verifications many factors (cutting speed, feed rate and depth of cut) effect on the surface roughness in cnc turning process. the experiments were conducted on cnc lathe type starchip 450 by using carbide cutting tool type dnmg 332, as shown in fig.1. (2) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 the work material used in this research is aluminum enac-43400 shaft. the diameter of the material is 46 mm and length is 150 mm. the chemical composition of work piece material was done by spectrometer device in the central organization for standardization and quality control and is given in table1, and mechanical properties of this work material shown in table 2. the surface roughness (ra) was measured by the pocket surf emd-1500 tester, as shown in fig.2. the workpiece was mounted using a pneumatic chuck in cnc lathe center and the clamping pressure was set as (8) bar. the machining parameters like cutting speed, feed rate and depth of cut were selected based on the manufacturer’s recommendations. experiments were conducted by varying the cutting parameters and the surface roughness values were measured using automatic digital pocket surf emd-1500 test. the tests were performed on a cnc lathe. the aluminum workpiece with dimensions of shaft diameter 46 mm and length of 150 mm was clamped in the turret of the cnc machine table. a computer numerical control program was written to perform the turning process. the parameters defined in the turning machine were cutting speed (m/min), feed rate (mm/rev) and depth of cut (mm). the taguchi lr9r orthogonal array were selected. the machining controllable: cutting speed, feed rate, and depth of cut parameters were depended (a, b, and c) and their levels are shown in table 3.the l9 orthogonal array with three columns and nine rows was suitable for use in this research. the controllable machining parameters and levels for surface roughness are arranged as shown in table 4 were each row represents an experiment with different combination of machining parameters and their levels. results and discussion the turning experiments were conducted and the readings of surface roughness and signal -to noise ratio (s/n) are given in table 5. the s/n ratio must be smaller as possible, therefore the quality characteristic "smaller is better" was used. then the results were analyzed depending on main effect for both surface roughness (ra) and signal to noise ratio (s/n) and the anova analysis. the average values of surface roughness and (s/n) ratio are determined for the controllable machining parameters (a, b and c) at each level as shown in table 6 and table 7 respectively. the values in table 6 are represents the average of surface roughness, for example level1 is represent the three experiments 1,2 and 3 in table 5 and computed as the mean of them: cutting speed (a) = (1.33+1.71+1.91)/3=1.65. feed rate (b) = (1.33+1.41+1.41)/3=1.383. depth of cut (c) = (1.33+1.36+1.14)/3=1.277. also for the level 2 are computed as follow: cutting speed (a) = (1.41+1.63+1.36)/3=1.467. feed rate (b) = (1.71+1.63+1.14)/3=1.493. depth of cut (c) = (1.71+1.41+1.34)/3=1.487. similarly for level three: cutting speed (a) =1.297. feed rate (b) =1.537. depth of cut (c) =1.65. the delta values that shown in the table 6 are represented the difference between the maximum and minimum mean response across levels of a factor (the overall change in a value). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 the graph that shown in fig.3 and fig.4 shows the main effect for surface roughness and s/n ratio. the best (smaller is better) surface roughness is obtained from the combination of controllable machining parameters a3,b1 and c1 (cutting speed 250m/min, feed rate 0.05 mm/rev and depth of cut 0.5 mm) which is refers to the optimum machining parameters. also the analysis of variance (anova) was performed using taguchi method in minitab 17 software as shown in table 8. from this table the contribution of each machining parameters was computed, depth of cut (47.727%) which represents the most influences machining parameters when machining this type of aluminum alloy (enac-43400), followed by cutting speed (42.500%) and last influences machining parameters is feed rate were its contribution rate was (8.409%). then a predicated surface roughness also made with using optimum controllable machining parameters were its value was( ra=1.014μm) by minitab 17 software conclusion: the main conclusions which can be deduced from this research can be summarized as follows: 1the surface roughness (ra) in this work is about (1.14-1.91μm). 2the best surface roughness was obtained from the combination of controllable machining parameters a3,b1 and c1 (cutting speed 250 m/min, feed rate 0.05 mm/rev and depth of cut 0.5 mm) which is refers to the optimum machining parameters. 3the contribution percentage of depth of cut (47.727%), followed by cutting speed (42.500%) and feed rate was (8.409%) when machining aluminum alloy enac-43400. references [1] anderson p. paiva and et al (2007) “a multivariate hybrid approach applied to aisi 52100 hardened steel turning optimization”, journal of materials processing technology, 189, 26-35. [2] anil gupta and et al (2011) “taguchi-fuzzy multi output optimization (moo) in high speed cnc truing of aisi p-20 tool steel”, expert system with application, 6822-6828,. [3] attanasio and et al, (2011) “study the effects of tool wear and cutting parameters on white and dark layer formation in hardened aisi 52100 bearing steel”. [4] basim a. khidhir and bashir mohamed (2011) “analyzing the effect of cutting parameters on surface roughness and tool wear when machining nickel based hastelloy-276” iop publishing,. [5] h. k. dava, l. s. patel, h. k. raval, (2012) “effect of machining conditions on mrr and surface roughness during cnc turning of different materials using tin coated cutting toolsa taguchi approach”, international journal of industrial engineering computations 3. [6] hussam l. alwan (2013)" determination the optimal cutting conditions affecting the surface roughness using taguchii method in turning (al-12%si) by carbide tool" the iraqi journal for mechanical and material engineering, vol.13, no.2. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 [7] ilhan and ali., (2010) evelopment of a eural etwork ased surface roughness prediction system using utting parameters and an accelerometer in turning , epartment of mechanical education, faculty of technical education, university of seljuk, turkey, ieee. [8] ilhan asiltürk and mehmet çunkas, (2011) “modeling and predication of surface roughness in truing operations using artificial neural network and multiple regression method”, expert system with applications 38, 5826-5832. [9] ilhan asiltürk and süleyman neseli, (2012) “multi response optimization of turning parameters via taguchi method based response surface analysis”, measurement volume 45, issue 4. [10] m. kaladhar and et al (2012) “ etermination of optimum process parameters during turning of aisi 304 austenitic stainless steel using taguchi method and a ova “international journal of lean thinking, volume 3, issue 1. [11] małgorzata kowalczyk (2014) "application of taguchi and anova methods in selection of process parameters for surface roughness in precision turning of titanium" advanced in manufacturing science and technology,vol. 38, no. 2. [12] p.g.kochure, k.n.nandurkar (2012) "taguchi method and anova: an approach for selection of process parameters of induction hardening of en8 d steel" international journal of advance research in science, engineering and technology, vol.01, issue 02, pp. 22 -27. [13] rakesh k. patel and h. r. prajapati, (2012) , parametric analysis of surface roughness (sr) and material removal rate (mrr) of arden steel on turning using a ova analysis , international journal of engineering science and technology, vol. 4, no. 07, india. [14] rama rao. s, padmanabhan. g (2012) " application of taguchi methods and anova in optimization of process parameters for metal removal rate in electrochemical machining of al/5%sic composites" international journal of engineering research and applications,vol.2, pp. 192-197. [15] raviraj shetty, r. p. (2008) "study on surface roughness minimization in turning of dracs using surface roughness methodology and taguchi under pressured steam jet approach" arpn journal of engineering and applied sciences, 3 (1), 59-67. [16] suleyman neseli, suleyman yaldiz, erol turkes, (2011) “optimization of tool geometry parameters for turning operations based on the response surface methodology”, measurement 44 580-587. [17] tian syung lan (2010) “fuzzy deduction material removal rate optimization for computer umerical ontrol turning”, american journal of applied sciences, 1026-1031. http://www.sciencedirect.com/science/journal/02632241/45/4 http://www.sciencedirect.com/science/journal/02632241/45/4 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 table (1): chemical composition of al enac-43400 alloy. element si fe mg mn cr cu ti zn other al wt % 10.40 0.72 0.34 0.21 0.02 0.1 0.05 0.15 0.15 bal. table (2): mechanical properties of al enac-43400 alloy. mechanical properties al enac-43400 alloy tensile strength 240 mpa 0.2% proof strength 140 mpa brinal hardness n. 70 elongation at fracture 1 % poisson’s ratio 0.3 table (3): machining parameters and their levels. level 3 level 2 level 1 unit machining parameters symbol 250 200 165 m/min cutting speed a 0.07 0.06 0.05 mm/rev feed rate b 1 0.75 0.5 mm depth of cut c table (4): taguchi l9 orthogonal array. machining parameters levels no. of experiment c b a depth of cut (mm) feed rate (mm/rev) cutting speed (m/min) 1 1 1 1 2 2 1 2 3 3 1 3 2 1 2 4 3 2 2 5 1 3 2 6 3 1 3 7 1 2 3 8 2 3 3 9 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 table (5): experimental surface roughness and s/n results. s/n (db) ra (μm) machining parameters no. c b a depth of cut (mm) feed rate (mm/rev) cutting speed (m/min) -2.477 1.33 0. 5 0.05 165 1 -4.659 1.71 0.75 0.06 165 2 -5.620 1.91 1 0.07 165 3 -2.984 1.41 0.75 0.05 200 4 -4.243 1.63 1 0.06 200 5 -2.670 1.36 0. 5 0.07 200 6 -2.984 1.41 1 0.05 250 7 -1.131 1.14 0. 5 0.06 250 8 -2.542 1.34 0.75 0.07 250 9 table (6): main effect for surface roughness (ra). symbol machining parameters average of ra(μm) delta (max-min) μm rank level 1 level 2 level 3 a cutting speed (m/min) 1.650 1.467 1.297 0.353 2 b feed rate (mm/rev) 1.383 1.493 1.537 0.153 3 c depth of cut (mm) 1.277 1.487 1.650 0.373 1 table (7): main effect for s/n ratio. symbol machining parameters average of s/n(db) delta rank level 1 level 2 level 3 a cutting speed (m/min) -4.253 -3.300 -2.222 2.031 2 b feed rate (mm/rev) -2.815 -3.347 -3.611 0.796 3 c depth of cut (mm) -2.095 -3.395 -4.283 2.188 1 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 table (8): anova table for surface roughness symbol sum of squares degrees of freedom mean squares f-value contribution % a 0.187 2 0.093 28.87 42.500 b 0.037 2 0.018 5.78 8.409 c 0.210 2 0.105 32.39 47.727 e 0.006 2 0.003 1.363 total 0.440 8 100 figure (1): cnc lathe use in experimental work figure (2): automatic digital pocket surf emd-1500. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 022 figure (3): main effect for surface roughness. figure (4): main effect for s/n ratio. template for academica science journal al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 216 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. numerical study for interrupted rectangular fins in a natural convection field ass. prof. dr. abbas jassem jubear department of mechanical engineering college of engineering-university of wasit email: abbasaljassani@uowasit.edu.iq ali hameed abd mechanical engineering department college of engineering, wasit university email: alialataby490@yahoo.com abstract: the heat sink with vertically rectangular interrupted fins investigated numerically in a natural convection field, and with steady-state heat transfer. numerical study has been conducted using ansys fluent software (r16.1) in order to develop a 3-d numerical model. the dimensions of fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins). the number of fins used on the surface are eight. in this study, the heat input that is used as follow (20, 40, 60, 80, 100, and 120 watts). the study is focused on interrupted rectangular fins with different arrangement of fins. the results show that the addition of interruption fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate obtained as an equation. keywords: heat sink, heat transfer, free convection, interrupted fins, cfd. . 1. introduction heat sinks are used in various engineering applications for the cooling of electronic and electrical appliances, communications equipment and vehicle components. these components can be either semiconductor devices or integrated circuits, and more accurately, uses passive cooling extensively in cpu cooling, amplifiers, and led light bulbs. natural convection heat transfer from vertical rectangular fins is a settled subject in the literature. here it has been investigated numerically. previous studies include numerical and experimental works, and further studies can be found elsewhere ranandan and ramalingam, 2008. salila and panda, 2013, studied numerical model by using ansys program in this project. the aim was to reduce the materials used, and made the fins with highly efficient and at relatively low cost. the fin form used is rectangular fin made of a metallic element and horizontal position, and exposed to the effect of natural convection. the results showed that when the heat input increased the heat transfer coefficient will increase and the nusselt number will increase. mehran and golnoosh, 2014, investigated the numerical and experimental study of vertically rectangular interrupted fins in a natural convection field. in order to create a two-dimensional digital model, ansys fluent was used to study the effect of interruptions numerically. the aim of this study is to add different interruption with a variable dimension to the vertical fins and then to find the optimum value of the interruption ratio. the results showed that the optimal interrupted length of the fin was obtained and related. ali and abbas, 2015, studied several models of interrupted fins, and with different interruption ratio under the natural convection effect. the governing equations of continuity, momentum, and energy equations have been solved with steady-state, laminar, two-dimension, and with boussinesq approximation using the fluent v15 software. the results show that the use of mailto:abbasaljassani@uowasit.edu.iq mailto:alialataby490@yahoo.com al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 217 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. interruption technique cause to reset the boundary layer, which enhances the thermal performance of the fins and also reduce overall weight. bhushan s rane, 2015, studied different models of the heat sink which contained continuous, inline-interrupted and staggered fins by using the fluent software. the study concluded that interrupted fins are more effective than continuous fins and that staggered fins are better than the rest. the results showed that staggered fins can be used to improve the thermal performance of attachments for a variety of electronic, electrical appliances, and communications applications. suha k. jebir, 2017, explained heat transfer by free convection for two types of fins 1-interrupted and 4-interrupted rectangular, by placing fins horizontally, vertically, and inclined. the base of the fin is susceptible to constant heat flux. comsol 5.0 package was used to find the mesh generation and locate the results. the results showed that convection heat transfer of the fin with a horizontal position was less compared with the following two cases (vertical and inclined). a numerical study was carried out starting from the continuous fin with dimensions of (101mm width, 305mm length, 2.5mm thickness, and 9.5 mm space between fins). after that, studied the effect of interrupting of the fin with different lengths of interruption (g = 10mm, 20mm, and 30mm) and numbers of interruption (n = 1, 2, 3, 4, and 5), in order to obtain the best ratio of the interruption (γ). after getting the best number of interrupting, changed the arrangement from inline interruption to staggered, with variable interruption length (g). the main purpose of this study is to obtain the best heat transfer coefficient and reduce the total weight. 2. problem statement when the fin base plate is heated from the bottom, the heat passes through the conduction to the vertical fins and the thermal boundary layers begin to evolve from the lower edges of the fins. if fins are long enough, thermal boundary layers will be fully integrated bejan, 1984. the interruptions of fin disrupt the growth of the thermal boundary layer while maintaining a thermal flow system, leading to higher natural heat transfer coefficient. three-dimensional (cfd) models with dissimilar patterns of heat sinks have been presented through this study. 3. numerical analyses this section includes discussion of the following sub-sections, computational domain, the governing equations, mesh generation, and precondition. in addition, validation of present numerical study and another previous numerical study has been discussed. 3.1 computational domain different sample of fins have been modeled as shown in table 1. the main species of fins (heat sinks) geometries are shown in fig. 1. table 1: dimensions of finned plate samples; interrupted and staggered fins. sample name n (number of interruption) g (mm) l (mm) n( number of fins) int.-1-10 1 10 147.5 16 int.-2-10 2 95 24 int.-3-10 3 68.75 32 int.-4-10 4 53 40 int.-5-10 5 42.5 48 int.-1-20 1 142.5 16 int.-2-20 2 88.33 24 al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 218 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. int.-3-20 3 20 61.25 32 int.-4-20 4 45 40 int.-5-20 5 34.2 48 int.-1-30 1 30 137.5 16 int.-2-30 2 81.6 24 int.-3-30 3 53.75 32 int.-4-30 4 37 40 int.-5-30 5 25.83 48 stag.-5-10 5 10 42.5 44 stag.-5-20 5 20 34.2 44 stag.-5-30 5 30 25.83 44 continuous fins arrangement in-line interrupted fins arrangement staggered interrupted fins arrangement al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 219 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. fig.1: considered heat sink geometries. 3.2 governing equations the dominant equations for the continuity, momentum, and energy are resolved by using the fluent r16.1 software. the processors of numerical study are divided into two parts. the first preprocessor is the program structure which creates the geometry and grid by using the fluent r16.1 software. the second post-processor is resolving governing equations which include conservation of mass, momentum, and energy for the purpose of obtaining the results. bocu and altac, 2011. the governing equations for this study are as follows: mass conservation equation: (1) momentum: (2) energy: (3) the heat in the fins is dissipated by three methods, conduction, convection, and radiation. the temperature field is gained by settling the energy equation. 3.3 mesh generation for the choice of meshing size, proximity and curvature size operate are taken into account. for higher meshing at the fluid-metal interface, inflation layer is taken into account. mesh independence study is performed for this study. fig.2 shows two different meshing model of a numerical model, which is created using ansys fluent r16.1 software. the first model is for meshing with minimum cell size1 mm while the second model shows mesh generation using 0.5 mm minimum cell size. after the numerical simulation of the fins for both sizes of the grid, the maximum temperature was determined. our result shows that selection of meshing size less than 1 mm has very less effect on temperature variation. for both the grid sizes the maximum temperature is about 154.5°c. finer meshing only increases the computational cost without further changes in maximum temperatures, so 1 mm meshing size is selected for all the ansys simulation in this study. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 220 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. (a) (b) fig.2: mesh independency of numerical model to thermal performance: (a) meshing with 1 mm minimum cell size; (b) meshing with 0.5 mm minimum cell size. 3.4 boundary condition the flow type in this numerical study is laminar. the effect of density variation with a temperature have been estimated by boussinesq approximation. in the current study, there are different values of heat flux (649, 1298, 1948, 2597, 3246 and 3896 w/m2) have been used. a very soft border layer mesh was used for areas close to the fin surface, in order to capture the flow behavior with high accuracy. the primary condition of the fin model at the base is a constant heat flux, the heat in the fin base is transmitted by conduction. at the surface of the fins, the heat transfer is carried out by convection and radiation as shown in fig.3, where the emissivity of aluminum (0.5) has been used. fig. 3 boundary condition. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 221 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 4. cfd modeling in this present study, the fins were placed on a base plate of dimension 305 * 100 mm2. the fin arrangement was put within the middle and therefore the bounding box was created as shown in fig. 4. the boundaries of this process domain were placed sufficiently far from the fins to avoid any flow-reversal throughout the numerical simulations. the cfd meshing, process domain discretization was performed mistreatment ansys software, a processor. combos of tetrahedral and prism parts were used. because of the high-temperature distinction between the fin surfaces and therefore the surroundings, the buoyancy currents are going to be dominant. the prism layers generated close the fin surfaces would facilitate to numerically resolve the thermal boundary layers and this lead to the improved accuracy of the general heat transfer 5. simulation results shows the most important results obtained. 5.1 validation of the present study: for the purpose of starting the current numerical study, they have been verified by comparison with mostafavi et al., 2012. through comparison between two studies it is found that there was a good agreement between the results, and the error rate does not exceed 2.7%.this validation for continuous fins as shown in fig.5. fig.4 cfd modeling. fig.4 cfd modeling. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 222 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. fig.5 validation of numerical analysis graph. 5.2 velocity and temperature contours: the main species of a heat sink has been chosen in order to show the effect of changing the arrangement on temperature and velocity through the contour. figs. 6, and 7 show the temperature and velocity flow contours for three models. from these contours shown the effect of interruption length on the thermal boundary layer noticeably. where the length of the interruption prevents the growth of the adjacent thermal layer that causes resistance to heat transfer to the ambient. the development of flow in the fin can be seen through argument regions. the contour of the temperature and the velocity flow were created in a level at the mid-height of the fin, and at value of heat input = 60 watts. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 223 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. fig.6: temperature contours; (a) continuous fins ;(b) interrupted fins;(c) staggered fins. (a) (b) (c) fig.7: velocity contours; (a) continuous fins ;(b) interrupted fins;(c) staggered fins. (a) (b) (c) al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 224 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 5.3 the variation between interruption ratio and heat transfer coefficient: the relation between heat transfer coefficient and interruptin ratio (γ) with different heat input can be seen in fig.8. the reason for increasing the heat transfer coefficient is that when the interruption ratio increases, the surface area decreases and the flow velocity increases at the base of the fin, thereby increasing the coefficient of heat transfer through natural convection. fig.8: the effect of interruption ratio on heat transfer coefficient with different heat input. 5.4 the effect of different heat input on temperature and nusselt number using the numerical results obtained, plotted a relationship between the heat flux and the difference in temperature for the interrupted fins (with different n and g) as shown in figs.9.to12. note from these figures that when increasing the length of the interruption (g) and the number of interruption (n) lead to increased temperature due to the decrease surface area of a heat sink. it is clear from figs. 13. to 16 depict the relation between different heat input and nusselt number with different g. the exhibit that the heat transfer coefficient enhances when the heat input, g and n increase. that means the interruption length leads to a higher thermal performance because interrupted fins prevent the thermal boundary layer growth, lead to increased heat transfer coefficient and thus increase the nusselt number with natural convection. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 225 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. fig.9: the effect heat flux on temperature different with different g at n=2. fig.10: the effect of heat flux on temperature different with different g at n=3. fig.11: the effect of heat flux on temperature different with different g at n=4. fig.12: the effect of heat flux on temperature different with different g at n=5. fig.10: the effect of heat flux on temperature different with different g at n=3. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 226 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. fig.13: the effect of heat input on nusselt number with different g at n=2. fig.14: the effect of heat input on nusselt number with different g at n=3. fig.15: the effect of heat input on nusselt number with different g at n=4. fig.16: the effect of heat input on nusselt number with different g at n=5. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 227 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 5.5 the effect of change arrangement on temperature and nusselt number through the study of numerical and comparative between the continuous and in-line interrupted and staggered interrupted fins. the following fig.17 and 18. show that staggered interrupted fins are better compared to other species because the surface area subjected to heat transfer is larger, then giving greater heat exchange as well as an improvement in the nusselt number. 6. conclusions: numerical studies performed in order to establish optimum geometrical heat sink parameters for natural convection heat transfer from interrupted rectangular fin arrays with different arrangement. the most important results of the numerical study can be listed as follows:  the results are based on the fact that when the fin length is increased, especially in the case of the continuous fin, the heat transfer coefficient is low. where the heat transfer coefficient reaches the lowest value at a length of 305 mm at same heat flux.  when the interrupting length is increased, the heat transfer coefficient increased, and increasing the number of interruptions leads to a clear improvement in the heat transfer coefficient. the model in which the number of interruptions is five and the interrupting length is 30 mm better than the continuous fins by ..22% in terms of heat transfer coefficient.  the optimum interrupted ratio (γopt) is a function of surface temperature, for different lengths and within this range ( 12 mm< l <25 mm), as follows: fig.16: the effect of heat input on nusselt number with different g at n=5. fig.17: effect of interruption on the temperature difference. fig.18: effect of interruption on the nusselt number. al-qadisiyah journal for engineering sciences vol.11, no. 2 issn: 1998-4456 page 228 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. (𝛄opt) = 8112(twall tamb.)-2.2  staggered interrupted fin arrangement provided better heat transfer rate in comparison with the inline interrupted fin arrangement. the ratio of improvement is 2.4%. references ranandan and ramalingam, thermal management of electronics: a review of literature. thermal science vol. 2 (2008). salila ranjan dixit, drtarinicharana panda, "numerical analysis of inverted notched fin array using natural convection" iosr journal of mechanical and civil engineering (iosr-jmce) volume 6, issue 4 (may. -jun. 2013), pp 47-56. mehran ahmadi, golnoosh mostafavi, "natural convection from rectangular interrupted fins", international journal of thermal sciencesvol.82(2014), pp.62-71. al-hamadani, ali af, and abbas jassim jubear. "numerical simulation of natural convection heat transfer from interrupted rectangular fins." journal of engineering 21.10 (2015). bhushan s rane, "numerical and experimental investigation of staggered interrupted fin arrangement in a natural convection field", international journal of engineering research and general science volume 3, issue 6, november-december, 2015. suha k. jebir. "effect of inclination interrupted fin arrays with iso-flux on convection heat transfer" international journal of application or innovation in engineering & management (ijaiem) volume 6, issue 1, january 2017. a. bejan, convection heat transfer, wiley, new york, 1984. z. bocu, z. altac, "laminar natural convection heat transfer and air flow in three-dimensional rectangular enclosures with pin arrays attached to hot wall", applied thermal engineering, 2011, pp. 3189-3195. mostafavi g., "natural convective heat transfer from interrupted rectangular fins", thesis in master of applied science, school of engineering science faculty of applied sciences, simon fraser university fall, 2012. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 410 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. wearable antennas 3.8 and 5.6 ghz using for indoor child monitoring dr. hayder jawad mohammed albattat, al-furat al-awsat technical university email: saidhaider75@yahoo.com hayder.albattat@atu.edu.iq received on 27 august 2017 accepted on 31 october 2017 published on 30 december 2017 doi: 10.30772/qjes.v10i4.489 abstract: in latest years the progress and employment of wearable antennas have developed quickly for human monitoring applications. due to shrink of wireless communication equipment reasons, the microstrip patch antennas with size-reduced are preferred. in this paper, two wearable antennas with different shapes (similar to the button) are introduced. these are compatible for a commercial wireless system platforms such wifi and wimax standards. the proposed antennas are very suitable for child indoor monitoring purposes. here, because of the small size of these antennas (the largest dimension approaches to 25 mm), the assumption of bending the surface, substrate and ground layer are neglected. the operation frequency band for the first antenna is between 5.4 and 5.6 ghz, while its between 3.6 to 3.8 ghz for the second and both with a linearly polarized radiation. for a wearable antenna, a conductive textile was used for the substrate layer, a permittivity of 4.4 is used. a 52% size reduction result of the rose patch size (the 2 nd antenna) compared to the size of a regular rectangular patch antenna (the 1 st antenna) additionally, investigations had been conducted for different antenna without bending and the antenna’s performance in vicinity to human body. the proficient multiphasic comsol software is used for simulation. keywords: wearable antenna, patch antenna, wi-fi, wi-max, wban, comsol. introduction the microstrip patch antennas with size-reduced is favourite for modern wireless applications [1, 2]. these type of antennas is very suitable for wireless body area networks (wban). wban have increased attention because of their wide applications in civilian and military, which used in medical sensor systems, rescue service applications, military communication or personal entertaining [3]. wban's applications in monitoring services have been growing. many bands of frequencies allocated for wban, such the medical implant communication system (mics) where 400 mhz is used, 2.4 ghz and 5.8 ghz bands for the industrial scientific medical (ism), low and high frequencies of the ultra-wideband (uwb) which lie between 3 and 10 ghz band [4-7]. in recent times, rapid increasing wireless equipment encouraged the development of modern wireless standards such wifi and wimax [6-7]. recent communications have characterised the transmission between different antennas located around the body [8]. wearable antennas have already been developed as metal patches with different shapes on textile fabric [7]. the antennas published in [8] were probe fed and linearly mailto:saidhaider75@yahoo.com mailto:hayder.albattat@atu.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 411 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. polarized while later development [8] achieved circular polarization [9] with a microstrip feeding line ensuring higher wearing comfort. more recently, the authors of the present manuscript introduced a wearable button antenna [6]. the rest of this paper is prepared as follows. section ii presents the proposed of antennas geometries. results and discussion confirmed at the third part of the paper. lastly, iv part shows the conclusions reached by the work. 1. geometries of the designed antennas two of geometrical shape of antennas with small size are introduced. the shapes of these antennas are similar to the button, where these entries are very suitable for clothing. the design of these antennas are taking of the base of a substrate square with size of 0.02 mm 2 as a wearable one for the child monitoring purpose. the line feeding technique for such type of antenna is microstrip which has been used for the basic circular button microstrip patch antenna. the detail of the dimensions of these aerials are shown in figure 1 and figure 2. glass epoxy (fr$) as a substrate is used. permittivity constant (εr) is approached to 4.4. figure 1: the layout of the proposed antenna no. 1. the horizontal and vertical views of the first antenna are shown in figure 3a and b , respectively. in other side, the horizontal and vertical views of the second antenna are shown in figure 4a and b, respectively. table 1 and 2 have the geometrical characteristics of the antenna 1 and 2, respectively. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 412 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: the layout of the proposed antenna no. 2. figure 3 a: horizontal view of the antenna no.1. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 413 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3 b: the vertical view of the antenna no.1. figure 4 a: horizontal view of the antenna no.2. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 414 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4 b: the vertical view of the antenna no.2. table 1: the dimension characteristics of the first antenna. name expression unit description d 5.8 [mm] substrate thickness wline 1.13 [mm] 50 ohm line width wpatch 60 [mm] patch width lpatch 60 [mm] patch length wstub 5 [mm] tuning stub width lstub 16 [mm] tuning stub length wsub 90 [mm] substrate width lsub 90 [mm] substrate length fmin. 2.5 [ghz] minimum frequency in sweep fmax. 4.4 [ghz] maximum frequency in sweep d1 110 [mil] patch thickness ɛr 4.4 rin 50 ohms al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 415 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 2: the dimension characteristics of the second antenna. name expression unit description d 1.5 [mm] substrate thickness wline 1.13 [mm] 50 ohm line width wpatch 60 [mm] patch width lpatch 60 [mm] patch length wstub 5 [mm] tuning stub width lstub 16 [mm] tuning stub length wsub 90 [mm] substrate width lsub 90 [mm] substrate length fmin. 1.5 [ghz] minimum frequency in sweep fmax. 6.5 [ghz] maximum frequency in sweep d1 110 [mil] patch thickness ɛr 4.4 dim 25mm x 25mm 2. results and discussions figure 5 related to the simulated electric field norm for the proposed first antennas. figure 6 shows the radiation pattern in 2d for the same antenna. the antennas have a good return loss for 3.6 ghz with respect to less than -14db as shown in figure 7. desired characteristics of wifi and wimax is achieved through the first antenna. it's obvious from figure 9 that for the resonant frequency of 5.6 ghz the return losses parameter s11 is less than -20 where its very suite to such application with respect to the required quantity of -10 db for such task. also this frequency is standard frequency for wifi, and local area requests. the desired frequency component is in band of 5.3 to 5.6ghz. the antenna realizes the required conditions for wireless body purposes. the two dimensions (2d) far-field [v/m] radiation patterns in of the proposed antenna (see figure 8), which denotes to the directivity and the gain of the antenna. the intensities of electric field is drawn for the fundamental frequency of our antenna as shown figure 5. to estimate the energy density per cubic meter through time interval. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 416 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: electric field norm for the proposed first antenna. figure 6: 2d radiation pattern for the proposed first antenna. figure 7: the frequency response of the first antenna. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 417 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 8: far field norm of the first antenna. figure 9: the insertions return losses response for the proposed second antenna. conclusions a wearable microstrip antenna, with geometrical based on the button and square shapes introduced here. a patch antenna attained the desired frequency which used for child monitoring requirements. the antennas have been analysed by using comsol software. the outlet of the simulation indicated that the antennas possess a wideband resonant compatible and suitable frequencies for the requests of the 3.8 till 5.8 ghz. these bands cross with wban, wifi, wimax, and other wireless telecommunication systems. performance of the most effective parameters of the antennas were considered. from the results of antenna 1's simulation , it is found that the improved resonant frequency has shifted from 5.1 ghz to 5.9 ghz with same size and dimension of patch antenna. it shows the return loss less than of -20 db at 5.6 ghz resonant frequency. for the antenna 2 the best resonant frequency is 3.8 with insertion loss equals to -14 db. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 418 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure10: radiation pattern (2d) for the proposed first antenna at 5.6 ghz. references 1. ahmed ghanim wadday and hayder jawad albattat, "design of reconfigurable microstrip antenna with wide tunability range for cognitive radio network," kufa journal of engineering, vol. 7, no.2, 2016, pp. 1-8. 2. ahmed ghanim wadday and hayder jawad albattat, " hidden kuldo, rotated square and kuldo fractol antenna of 2.4 to 5.4," journal of engineering and sustainable development, vol. 20, no. 3, 2016, pp.47-59. 3. d. d. cara, j. trajkovikj, r. t. sánchez, j. f. zürcher, and a. k. skrivervik, " a low profile uwb antenna for wearable applications the tripod kettle antenna (tka)," ieee, 7th eu. conf. on antennas and propagation , eucap , 2013, 3257-3260. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 419 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4. k. dwibedi, p. patel, p. r, d thiripurasundari and z.c alex, "dual band cpw fed wearable monopole antenna," ieee, proce. of conference on information and communication technologies, ict 2013, pp. 1134-1137. 5. s. sankaralingam, s. dhar and b. gupta, "preliminary studies on performance of 2.45ghz wearable antenna in the vicinity of human," ieee, international conference on communications, devices and intelligent systems (codis), kollkata, india, 2012, pp. 250-253. 6. z. h. jiang, d. e. brocker, p. e. sieber, and douglas h. werner, " a compact, low-profile metasurface-enabled antenna for wearable medical body-area network devices," ieee transactions on antennas and propagation, vol. 62, no.8, august 2014, pp. 4021 – 4030. 7. k. agarwal1, y.-x. guo1, b. salam and l. ch. w. albert, " latex based near end fire wearable antenna backed by amc surface," ieee mtt-s international microwave workshop series on rf and wireless technologies for biomedical and healthcare applications (imws-bio), 2013. 8. e. g. lim, z. wang, j. ch. wang, m. leach, r. zhou, ch. u. lei and k. l. man, " wearable textile substrate patch antennas," engineering letters, may 2014. pp. 94-101. 9. effat o. el khashab and hany f. hammad, "a size-reduced wearable antenna for zigbee indoor localization," ieee, radio and wireless symposium (rws), santa clara, ca, usa, jan. 2012 pp. 95-98. 10. e. k. kaivanto, m. berg, e. salonen, and p. d. maagt ," wearable circularly polarized antenna for personal satellite communication and navigation," ieee trans. on antennas and propagation, vol. 59, no.12, dec., 2011, pp. 4490 – 4496. al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 148 al-qadisiyah journal for engineering sciences . all rights reserved. rfid based smart lock implementation asst. prof. dr. mohammed n. h. al-turfi computer engineering department, college of engineering, al-iraqia university,iraq. email : mohammed-alturfi@yahoo.com engineer rami ahmed adnan netwok engineering department, college of engineering, al-iraqia university,iraq. email:ramiadnan01@gmail.com received on 11 january 2018 accepted on 22 january 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.526 abstract: all people now a day are focusing on an important issue which is 'security' where all rigid, worthy dealing with, and creditable companies pay a lot of attention for this problem. therefore the cost, usage, portability must be taken in consideration. this work demonstrate the use of a smart, small, not expensive and the most important realistic portable lock with portable low consumption power supply and security coverage area with minimum side effect and maintenance. this lock is not the representative for a key but it may represent a badge, an id, or a credit card or social security card …. etc. so it’s very close to the use of the human normal day life and hence it will not be a security burden since the security card may be embedded within other cards like car security card or credit card …etc. the system is implemented and tested with no need for a sophisticated material but easy equipment may stand enough to achieve the job with very accept able cost. the system achieves high security password and a master electronic key that cannot be copied within the available constraint and high control operating environment and a backup plan in case of key lost. keywords: smart lock, arduino, rfid. introduction the rfid is a capturing data system that is used for automatic identification threw wireless channel, this is implemented using electromagnetic fields to identify accordingly tracked tags automatically and " which contain electronically stored (burned in) information "attached to objects is the general operating principle of rfid technology ,and particularly in rfid locks [1]. the environment of the rfid contains normally two major parts, the reader and the tag, while there are two types of rfid tags, passive and active, where passive one's collect the necessary energy transmitted from a nearby rfid reader's that generates the necessary operative radio waves hence the overall system coverage distance is small. while a local power source such a battery or solar cells must be available on board the active tags to power the system and hence the system may operate up to hundreds of meters from the rfid reader ,unlike some other technologies where the tag need not to be within the line of sight of the reader, like the barcode, it may be embedded in the tracked object, rfid is replacing barcode technology and enjoys the major advantages of being line of sight problems independent and support objects scanning from distance.[2] al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 149 al-qadisiyah journal for engineering sciences . all rights reserved. carrying and conveying data in suitable transponder media is the objective of any rfid system, generally tags task is to retrieve data, by classical, easy, or sophisticated readable means, with a time and place constrains to carry particular application and satisfy the needs. therefore this technology is one of the most pushing up by both industrial and academic world where millions of advanced books; periodicals & scientific magazines, cds, dvds, conferences and other electronic reading materials and articles are contained. it is a challenge to manage for librarians, managing such type and amount of huge collection. [3] many reasons for using rfid tags in many industries threw manufacturing and after sell, for example, an rfid tag attached to an equipment whether its heavy like a car or truck or light like a mobile phone or a home electric device during production can be used to track its progress through the assembly line or to provide mountainous and identification after sell. [1] size and mobility of rfid tags open new approach and made it available for attaching to cash, clothing, and possessions, or implanted in animals and people, the possibility of reading personally-linked information without consent has raised serious privacy concerns [2]. but on the other hand there are some sophistications available because rfid system is small and low cost and it can scan tags at rates of hundreds per second by the use of radio frequency (rf).[3] these concerns resulted in standard specifications development addressing privacy and security issues. iso/iec 18000 and iso/iec 29167 use its own developed system for un traceability cryptography methods, tag and reader authentication, and over-the-air security and privacy. iso/iec 20248 specifies a data structure authentication which is digital signature for rfid and barcodes providing data, source and read method authenticity.[2] with market stocks start from us$6.96 billion in 2012 rises about 10% to reach us$7.77 billion in 2013 , rises more than 15% in 2014, the rfid market is worth us$8.89 billion. this includes tags, readers, and software/services for rfid cards, labels, fobs, and all other form factors. the market value rises in 2015 to us$18.68 billion and it reaches up to us$30 billion in 2016 [4]. 1. system constructions the system as shown in fig(1) consists of two major parts, the s/w & h/w one. the s/w where implemented and imbedded within the electronic card using c++ programming for the following important reasons: 1-in-order to be able to modify or update the system software to handle new features and technologies. 2-c++ script are one of the most powerful programming techniques that may stand to achieve high outputs and controlling abilities. 3-c++ programming may inter-prater with other programming languages and smoothly interface with them. the h/w where implemented using three major devices: 1-arduino electronic card, which represents the heart of this system and the job controller with the following specifications:  operating voltage(logic level): 5 v  input voltage (recommended): 6v 12 v  digital i/o pins: 14 (of which 6 provide pwm output)  analog input pins: 8  dc current per i/o pin: 40ma  flash memory where it may be 16 kb (atmega168) or 32 kb (atmega328) where 2 kb used by boot-loader  sram: 1 kb (atmega168) or 2 kb (atmega328)  eeprom: 512 bytes (atmega168) or 1 kb (atmega328)  clock speed: 16 mhz al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 150 al-qadisiyah journal for engineering sciences . all rights reserved. 2-relay :which represents the job implementer and responsible for transducing the electric power into mechanical behavior threw control signal initiated by the arduino triggered by the rfid card or the reader as shown in fig(2). 3-rfid card reader :which is the job identifier where different types of rfid readers and cards with different operating frequencies may be used according to the implementation purposes and needs. but in general the rfid frequency ranges are all safe dealing with in & out door since the operating power is relatively low "where passive rfid are zero power since the operation depends on the out collected power". 2. system implementation the system implementation must pass threw two phases teaching (or learning) & identifying where in the each phase some operations must be implemented in order not to miss the security issues and not to let any intrusion may hack the system. 2.1. learning phase in this phase three operations must be taken in consideration and implemented in sequence to achieve the phase successfully: 1-there must be a specification for the code to be burned inside the rfid card which must be unique and representative for the person who carry the card and distinguish the level of authorization to specify card auxiliary functions . 2-there must be a code burner to down load the code to the card which has the ability to update it if necessary or duplicate it in case of losing or stealing with new tags and disable the old ones. 3-the number of users must be specified according to the reader memory size since each code is downloaded inside an rfid card must be duplicated and saved inside the reader data base for comparison and decision. 2.2. identification phase important constrain since the user can be identified if the user inside the system distance range elsewhere the system will not recognize the user rfid card. the code identification process must check sections, person, and number, where incompatibility of any part means that the person is either try to access the wrong section-room or the person is not authorized to access this section-room. figure 2:relay operating principle and control figure 1: the system electronic board al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 151 al-qadisiyah journal for engineering sciences . all rights reserved. an alternative plan is adapted in case of losing or stealing the rfid card where the lock will not response for the right card unless a number will be entered after checking the card and hence the entrance will be secured. 3. system operation the operation starts when the rfid card passes within the distance range of the card reader, it takes the code inside the card by electro-magnetic induction since rfid communication tool that used to uniquely identify tagged object , possessions or people. the code contains 16 digits each digit written in hexadecimal where the first 4 digits to specify the section, the second 4 digits specify the person level of authorization, while the 8 digits left specify the person number. in this case the number of probable cases is 16^16, this means that the correct number may be one of 1.8446734*10^19choices, so the probability of breaking the lock is very low and hence the lock is relatively high secured. when the system checks the user authentication depending on the card code and the secret number, the arduino will trigger the relay to change status from off to on where the power needed for the lock actuator will be reached and the system take the appropriate action. the action still active until the system status changes where it backs to its previous state, hence the system original status may easily specified whether its active high (lock) or active low (unlock) depending on the case applications. the system pin operation is the same as above where the rfid reader transmit the power through its reader antenna using pin(11). when the specified rfid card is detected by the reader the reader will activate the system microcontroller using pin(10) where pins (9,10,11) are analog pins. relay has 3 inputs and 2 outputs. the system relay will be activated through pin(7) where other two inputs are vcc which is 5volts and the ground which is one of the pins(5,6,14). pins(12,13) are digital where they are inputs to the rfid reader, the supply voltage to the rfid reader is 3.3 volts, pin(9) is the rfid reader reset where this pin activate the system start over after each action to be taken, hence the reader overall number of pins is seven. finally 12volts is the supply for the door lock which is the output from the relay to activate the actuator. conclusions a prototype home/ office automotive lock using rfid is designed and implemented with small size, low cost, high security, low power consumption, and the most important easy to maintain dedicated for automatic door control. this prototype operates in a safe frequency ranges that considered green specially the passive rfid where no power is available on board the card. at the same time the system may be adapted to achieve multi tasks since the rfid tag may hold up to 4 codes hence each code may hold certain task activated through certain relay activated by its own control signal to hold its task. side by side , and according to its small size it can be considered as a tariff card not only a key to lock since the rfid tag is embedded inside the car security remote control. which means that this prototype can control various devices and developed for controlling lights and fans …etc in smart green homes. one more property is that the system may be programmed using other programming languages than c++, where a java version of the system is implemented on the same board and equipments where the achieved task quality is identical to that programmed using c++. references 1. dr. prabhat .p, ms. k.d. mahajan, “application of rfid technology in libraries and role of librarian”. 2013. 2. kamrana, hanifa s, and paul k, “rfid applications: an introductory and exploratory study”, faculty of computing, engineering & technology staffordshire university stafford, st18 0ad, uk, 2013. 3. v. d. hunt, a. puglia and m. puglia, “rfid-a guide to radio frequency identification”, john wiley & sons, inc., technology, 2012. al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 152 al-qadisiyah journal for engineering sciences . all rights reserved. 4. ann cavoukian, ph.d., “privacy implications of radio frequency identification (rfid) technology”, commissioner february 2004. 5. zhi l, “ introduction to microsoft access 2003”, school of information fall/2006. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 372 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. study the effaect of tween 80 on clthrate hydrate formation behavior for r-134a shurooq t. al-hemeri department of chemical engineering, university of technology, baghdad, iraq. .e-mail: 80024@uotechnology.edu.iq riyadh s. al-mukhtar department of chemical engineering, university of technology, baghdad, iraq. e-mail: rnsa1962@yahoo.com mustafa s. mohammed department of chemical engineering, university of technology, baghdad, iraq. e-mail: 080549@student.uotechnology.edu.iq abstract: :clathrate hydrates are complex molecules formed by the contact between water and gas at high pressure and low temperatures. one of the important aims of gas hydrate technology is to enhance the formation of hydrate and reduction the induction time for clathrate formation. effect of the different promoters (nonionic surfactant tween80) on r-134a gas hydrate formation has been investigated in the isochoric system experiment. it is noted that the surfactants have a significant effect of increasing the speed of nucleation as well as improving the growth of hydrate. in the experiment, the effect of tween80 surfactant was studied to determine its effect on the composition and cooling capacity of 134 hydrates. from kinetic models, many objective functions such as the amount of gas consumed (∆n), the growth rate (r (t)), the apparent rate constant (kapp) and conversion of the water to hydrate were obtined. the improvement of hydrate growth is marked by the addition of surfactants, which in turn increase the solubility of hydrate gas and reduce the contact angle. in addition, surfactants positively the contact with the gas through the increase of the gas diffusion in the water and this increases the rate of formation of hydrate. best value achieved at a surfactant concentration of 100 ppm with maximum gas consumed amount (0.16 mol) and less indction time 32 min. keywords: key words: clathrate; gas hydrate; surfactant; refrigerant; thermodynamics model mailto:80024@uotechnology.edu.iq mailto:rnsa1962@yahoo.com mailto:080549@student.uotechnology.edu.iq journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 373 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. nomenclature symbol description unit a parameters of eos mpa.(l/mol)2 b parameters of eos (l/mol) c langmuir constant of cavities [-] ƒ fugacity of the gas component mpa kapp rate constant of hydrate reaction mol/(min.pa) n number of water mol mol p pressure bar q parameters of eos [-] r parameters of eos [-] r universal ideal gas constant m3.pa / (mol.k) t temperature k or 0c t time minute tind induction time minute v volume m 3 vcell volume of the cell m 3 𝐯𝐖 𝐋 molar volume m 3/mol 𝒗𝑾 𝑴𝑻 volume of the empty hydrate lattice m 3 /mol z compressibility factor [-] sc storage capacity v/v tstp temperature at stander condition k or 0c pstp pressure at stander condition bar introduction a clathrate is a complex molecule formed by the contact between gas and water at high pressure and low temperatures (sloan,2008). the cavities within hydrate formation are formed by the hydrogen bonds which occupied by the gas molecules that are the guest molecules (clark,2001).clathrate technology is most useful in industrial application such as desalination process, gas supply, separation of greenhouse gases, food engineering etc. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 374 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. enhancing the formation of hydrate and the tendency to reduce the induction time needed to form hydrates is one of the main objectives of gas hydrate technology. induction time is one of the most important parameters used to characterize hydrate nucleation, this time elapsed to form water and gas groups and their growth towards a stable nucleus with critical size known as the nucleation stage. the induction time can be expressed by the relationship between the pressure-time of the system in which the gas hydrates are formed as shown in figure (1). the initial pressure drop from p0 to psol caused by dissolution of gas in the liquid aqueous phase. at a steady-state conditions, the pressure stable until formation at which a sudden pressure drop is gas hydrate starts formation. the process of gas consumption continues to leading to low pressure until it reaches a stage where the hydrate is not formed (sabil, k. m.,2009). the induction time is calculated as: induction time = tinduction – tsol (1) figure 1. typical pressure-time-temperature plot obtained during a hydrate formation at constant volume (sabil, k. m.,2009). the enhancement of hydrate formation or reducing of induction time for clathrate formation is not easy to achieve because of the volume of hydrate formation layer and the induction time depends on factors such as promoter choice, guest choice, initial pressure, temperature and concentration of promoter. slow formation of gas hydrate has been a critical problem hindering of gas application (kalogeraks,1993). scientists have revealed the advancement impact of a few added substances on the formation of gas hydrate and hydrate gas content. one of the techniques for enhancing the hydrate formation increases the interface accessible for the reaction of hydrate (han,2002). this can be done effectively by different methods such as mixing water and gas, spraying the water with gas, or by immersing a porous medium in water (go y,2002). another system is the use of synthetic additives, which includes thermodynamic hydration promoters, or motor hydrate promoters, and generally surfactants. add surfactant enhancing the hydrate formation by increasing the interface accessible for the hydrate reaction (kang,2001).the surfactants are made up of hydrophobic particles and hydrophilic particles where they show an admiration for polar and journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 375 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. non-polar materials, which are critical factors in the growth rate of hydrates as shown in figure (2) (kumar,2013). figure 2. (a) a surfactant molecule with the hydrophilic particles and lipophilic particles groups and (b) formation of micelle in aqueous solution media through association of surfactant molecules(kumar,2013). the spread of the surfactant is from the large phase towards the interface which leads to the change of the contact point between the phases and the solid surface, which in turn leads to a change in the charge and viscosity of the surface (shah,1997). the atoms of the surfactants form different forms when they reach the appropriate concentrations and called these structures (micelles) and have different orientations and shapes (circular, pole like micelles, multilayer structures) (kumar,2015). the surfactants plays an important role in enhancing hydrate formation especially in industries where arranging micelle is one of the basic requirements that showed in figure (3) (suradkar,2006). journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 376 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 3. mechanism of hydrate formation (kumar,2013). several authors reported that adding of surfactant tween80 as a promoter of the liquid water and gas guest produces clathrate hydrate utilization of surfactants in gas hydrate-related investigations was continuous since the mid-1990s (peytavy,1998). the surfactant has been accounted for that the viability of these surfactants for promoting kinetics are system particular (lim,2013). tween80 is a polyethoxyl derivative of oleic acid and sorbitan, a water-soluble yellow liquid that is often used in foods. the polyethers are the hydrophilic group and are also known as polyoxyethylene, ethylene oxide estimated polymers (zhang,2003). kalogerakis in 1993 was explained that the behavior of the inhibitor of the surfactant and found that the procedure can be promoted with a little concentration of the surfactant. zhong and rogers in 2000 demonstrated that the rate of gas hydrate formation could be increased by increasing the concentration of sodium dodecyl (sds) above the primary micelle concentration. gou in 2002 was explored the calcium hypochlorite impact on the limit of methane capacity and methane hydrate formation rate. kumar in 2013 studied the three types of surfactant (ionic, cationic, and non-ionic) for their effect on the hydrate formation of carbon dioxide; he noted that the best promoting in hydrate formation and reduction of induction time is (sds). nonionic surfactant (tween-80) was observed on the cationic surfactant. zhang et.al. in 2008 showed solubilization of surfactants produces supersaturated gas molecules, which promotes the mass transfer from a bulk phase to hydrates and provides the driving force for the complexation between host molecules (water) and guest molecules in a gas hydrate formation process and when most of the gas molecules are bound to form clusters with water molecules, which promotes the formation of crystal nuclei of gas hydrates. al-mukhtar et la in 2018 studied journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 377 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. kinetics dissociation for the binary system (water-r-134a) system and for ternary salts (nacl, kbr, and naf) system at different concentrations (0.09, 0.17, 0.26)mol/kg in the isochoric cell. they used claperyon equation to estimate dissociation heat for the systems with peng-robinson – prsv equation applied for gas compressibility factor z. they concluded that dissociation heat increased when salt concentration increased. the nacl salt with high concentration gave the highest value among the other salt in the study. in this study, growth rate, induction time, gas consumed, apparent rat constant, storage capacities and conversion of water to hydrate of the hydrates formed in presence of nonionic surfactant (tween 80) were investigated. the aim has been to find the best concentration of surfactant which achieves best values. 2. experimental 2.1 materials refrigerant gas (r-134a) )frisco, belgium( with a high purity equal to 99% was utilized to form a hydrate with distilled water. in experiments, surfactant was used was very soluble tween 80 (central drug house, india) with chemical formula c32h60o10, density (1.06-1.09) g/ml and viscosity (300-500) centistokes at 25°c. 2.2 apparatus figure (4) shows the experimental schematic diagram that used in this study. the most important part in the system is the glass cell with a total volume of 1500 cm3 and having internal diameter of 14 cm and height of 14.5 cm, the cell was equipped with a magnetic stirrer. a thermocouple type k with a division scale of 0.1 k and a digital pressure gauge with a division scale of 0.005 bar were to measure the temperature and pressure. the cell connected to the system through pipes and controlled by a valve for gas injection, water input, and drain valve. the cell surrounded by transparency plastic vessel as heat jacket to maintain the temperature inside the cell, cooling water supplied from bath type julabo f10-vc was used contains a cooling medium made of ethylene glycol/water with ratio about (1/3) by vol.. the temperature of the medium is adjusted by the controllable circulator. http://dictionary.sensagent.com/centistoke/en-en/ journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 378 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure.4 (1) gas cylinder; (2) needle valve; (3) gas compressor; (4)condenser; (5) accumulator of gas; (6) experimental cell; (7) magnetic stirrer; ; (8) water pump; (9) digital pressure gauges; (10) temperature sensor; (11) valve drain; (12) chiller; (13) interface system; (14) computer. 2.3 experimental method the constant volume (isochoric) system search strategy was utilized to investigate hydrate formation in this study (al-mukhtar, 2018). at to start, distilled water was used to wash the cell and after that washed with acetone to flush the cell. washed water and acetone lingering were depleted. the cell was emptied to vacuum pressure for a time of 30 min to guarantee that there were no traces of contamination. the air is evacuated from the reactor using the compressor after feeding of 200 ml (13% vol of the cell)of water solution mixture inside the cell. a specific measure of r-134a was acquainted of the cell (86% vol of the cell) with achieving the coveted pressure of 0.45 mpa (4.5 bar) at a temperature of 313.15 k (10 0c ). the mixer was rotates at 250 rpm after the gas pressurized to the cell is completed. the pressure of cell reducing consistently because of hydrate formation until the point when achieving the steady state condition. the stirring speed is set at 250 rpm and initial temperature and pressure at 10 0c and 4.5 bar respectively with select nonionic surfactant (tween 80) at different concentrations 0, 25, 50, 75 and 100 ppm. hydrates are separated by water discharge (non-converted to hydrates) by pressure inside the cell and thus the hydrate is extracted. 3. thermodynamics model 3.1 gas consumed the moles of the hydrate former consumed throughout the formation of hydrate are obtained by applying the real gas law as follows: journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 379 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. ∆nh = ng,0 ng,t = ( 𝑃𝑉 𝑍𝑅𝑇 )0 ( 𝑃𝑉 𝑍𝑅𝑇 )t (2) the "0" subscripts refer to the initial conditions where "t" refers to conditions at time, t, of the system, p pressure and t temperature at the phase equilibrium state, r was the universal gas constant, and z was the gas compressibility determined by the pitzer’s correlation (smith,2001): z=1+b0 𝑃𝑟 𝑇𝑟 + ω b1 𝑃𝑟 𝑇𝑟 (3) where b0 = 0.083 0.442 𝑇𝑟 1.6 (4) and b1 =0.139 0.442 𝑇𝑟 4.2 (5) the hydrate number (number of water molecules) is identified by the partial filling the large and small cavities. the simple hydrate number is calculated vrwt is the reacted water’s volume (sloan,2008): m = 136 ( 8𝜃𝑠 + 16𝜃𝐿) (6) where θs and θl are is the fraction of linked large and small cavities occupied by guest molecules respectively, as follows (sloan,2008): θi = (𝐶𝑖 × 𝑓𝑖) 1+(𝐶𝑖 × 𝑓𝑖) (7) ci is the langmuir constant for large cavities and small cavities for r134a hydrate. where fi is the fugacity of (r134a) gas which calculates by the apply equation of state (peng–robinson) (robinson,1976). the langmuir constant of r-134a ci is formulated as follows(j.munck,1988): ci = 𝐴𝑖 𝑇 exp( 𝐵𝑖 𝑇 ) (8) where ai and bi are constants with values 0.00575 and 4908 for large cavities respectively and cs equal to zero for (r134a) gas (p.t.ngema,2016). journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 380 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. the gas hydrate volume is not like the aqueous solution volume, to estimate the volume of r134a gas hydrate inside a cell the next equation used: vt = vcell – vs0 + vrwt – vhs (9) where vcell is the cell volume with value equal 1500 cm 3; vs0 is the initial aqueous solution volume with value equal 200 cm3; vht is the produced hydrate’s volume and vrwt is the reacted water’s volume which calculated by using the following equation: vrwt = m × ∆nh × vw l (10) where vw l displays the molar volume of water that may calculate by the next relation (j.b.klauda,2000): vw l =18.015×[1 − 1.0001 × 10−2 + 1.3339 × 10−4(1.8(𝑇 − 273.15) + 5.50654 × 10−7(1.8(t − 273.15) + 32)2] × 10−3 (11) the hydrate molar volume, vht, can be estimated by the next equation: vht = m × ∆nh × vw mt (12) the gas hydrate molar volume can be assumed equal to the empty hydrate lattice molar volume. klauda and sandler presented the vw mtis the volume occupied by empty hydrate lattice (in k and m3/kmol) as a function of temperature and pressure by following equation (j.b.klauda,2000): vw mt=(17.13+2.249×10-5×t+2.013×10-6×t2× 10−30 𝑁𝐴 136 -8.006×10-9×p+ 5.448×10-12 ×p2 ) (13) t and p are the temperature and pressure given in k and mpa units, respectively. 3.2 the growth rate of hydrate formation the growth rate of hydrate formation be presented using the below equation [hashemi h.et al.; 2014]: journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 381 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 𝑟(𝑡) = − 𝑑𝑛𝑅134𝑎 𝑑𝑡 |𝑡𝑖 = ∆𝑛𝑅134𝑎 ∆𝑡 |𝑡𝑖 = (𝑛𝑅134𝑎,𝑖−1−𝑛𝑅134𝑎,𝑖+1) (𝑡𝑖+1−𝑡𝑖−1)∗𝑛𝑊0 (14) 𝑛𝑅134𝑎,𝑖−1 and 𝑛𝑅134𝑎,𝑖+1 present moles of r134a gas which is hydrate former at 𝑡𝑖−1 and 𝑡𝑖+1respectively. nw0 is the initial number of moles of water. 3.3 the apparent rate constant the rate of growth of formation forr134a hydrate may be formulated as[hashemi h.et al.; 2014]: r (t) = 𝑑𝑛 𝑑𝑡 = k(𝑓𝑔 𝑣 − 𝑓𝑒𝑞 ) (15) at a specific time ti, the apparent rate constant is estimated by the expression below: kapp = r(t) (𝑓𝑔−ƒeq)ti (16) which kapp re0presents the rate constant of hydrate reaction. 3.4 water to hydrate conversion the water converts to hydrate for each mole of water feed can be estimated by relation below [babaee s. et al.; 2015]: the water conversion = m× ∆n nw0 ×100% (17) 3.5 the storage capacity (sc) the storage capacity is a volume of gas stored in per volume of hydrate which calculates by following equation (suradkar,2006): sc = 𝑉𝑆𝑇𝑃 𝑉𝐻 = ∆𝑛 ×( 𝑅×𝑇𝑆𝑇𝑃 𝑃𝑆𝑇𝑃 ) 𝑉𝐻 (18) where subscript stp stands for the standard conditions and vh is the gas hydrate volume at the end of the reaction, which is calculated by eq. (12). figure(5) shows the algorithm of previous calculation for calculating the gas consumed (δn), hydrate growth rate (r(t)), apparent rate (kapp), conversion of water to hydrate, and storage capacity of r-134a gas. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 382 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure (5): the suggested algorithm to calculate the gas consumed and the apparent rate hydrate formation of r134a. 4. result and discussion in the isochoric system, the pressure drop and the variation of gas consumed in the system of pure water ,r-134a and in the system of pure water ,r-134a and different concentrations for tween 80 are the resulted from dissolution when gas dissolved in the liquid aqueous phase, the nucleation when the pressure is stable until formation and formation process when hydrate start growth. however, when the hydrate formation growth stops, the pressure is stabilized because of the hfc134a is supersaturated and phase equilibrium has been reached as shown in figure (6a,b,c,d, and e). t=ti+∆t input p0,t0,vcell,vso, pc, tc, ω, r read pexp., texp. subroutine for calculate (z) calculate hydration number (m), vwl, vwmt calculate δn calculate vrw ,vht calculate v ̶̀̀̀ = v cell –v s0 + v rw v ht t = v ̶̀̀̀ v tassume v yes no gas consumed (δn) calculate hydrate growth rate (r(t)) end calculate apparent rate (kapp) calculate conversion of water to hydrate start calculate storage capacity (sc) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 383 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 6a. pressure-time-gas consumed behavior obtained with pure water and (without tween 80) 2 2.5 3 3.5 4 4.5 5 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0 10 20 30 40 50 60 1.6 2.1 2.6 3.1 3.6 4.1 4.6 5.1 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0 10 20 30 40 50 60 time (min) p r e ssu r e (b a r ) g a s c o n su m e d (m o l) time (min) p r e ssu r e (b a r ) g a s c o n su m e d (m o l) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 384 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 6b. pressure-time-gas consumed behavior obtained with 25 ppm concentrations of tween 80 figure 6c. pressure-time-gas consumed behavior obtained with 50 ppm concentrations of tween 80 figure 6d. pressure-time-gas consumed behavior obtained with 75 ppm concentrations of tween 80 1.6 2.1 2.6 3.1 3.6 4.1 4.6 5.1 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0 10 20 30 40 50 60 1.6 2.1 2.6 3.1 3.6 4.1 4.6 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0 10 20 30 40 50 time (min) p r e ssu r e (b a r ) g a s c o n su m e d (m o l) time (min) p r e ssu r e (b a r ) g a s c o n su m e d (m o l) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 385 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 6e. pressure-time-gas consumed behavior obtained with 100 ppm concentrations of tween 80 from figure (6a,b,c,d, and e), it can also be seen that when formation region is reached, the gas hydrate forms in pure water is about 48 min, in the water solution with 25 ppm of tween 80 in about 40 min, in the concentration of 50 ppm about 38 min, in the concentration of 75 ppm about 36 min and in the concentration of 100 ppm about 32 min. hence, the formation process of hfc134a hydrate is shorted with increasing mass fraction of surfactant tween 80 in the water solution. due to the low solubility of gas in water, hydrates appear on the water front in the pure water system. hydrates also cover the water interface which prevents further water conversion to hydrates, even when stirred due to the low water density compared to water is applied in figure(7). 1.6 2.1 2.6 3.1 3.6 4.1 4.6 5.1 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0 5 10 15 20 25 30 35 40 45 time (min) p r e ssu r e (b a r ) g a s c o n su m e d (m o l) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 386 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure. 7. gas hydrates presenting out in the cell with different concentration of tween 80. by eq. (2), figure (8) in comparison with the gas consumed in the pure water system with the presence of the surfactant in various concentrations 25, 50, 75 and 100 ppm, when increase the surfactant concentration, the gas consumed amount increases and the formation of hydrates increases. as shown in fig. 8 maximum gas consumed amount was achieved at a surfactant concentration of 100 ppm and the steady state of hydrate is realized in about 42 minutes and the induction time is shortest figure (9). journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 387 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure.8. refrigerant gas (r-134a) mole consumed without and with different concentrations of tween 80. induction time at 50 and 25 ppm is 26 and 30 min respectively. at 75 ppm the hydrate attains a steady state in about 44 minutes and the induction time is 24 min which is longer than that of 100 ppm. as figure (10) shows, surfactant promoter increase the gas hydrate storage capacity of. 0.0863 mole is the maximum gas amount in hydrate and 60 v/v is the maximum storage capacity of hydrate at standard condition. 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0 10 20 30 40 50 60 pure water 25 ppm 50 ppm 75 ppm 100 ppm 0 5 10 15 20 25 30 35 40 1 2 3 4 5pure water 25 ppm 50 ppm 75 ppm 100 ppm time (min) m o le s o f r -1 3 4 a c o n su m e d (m o le ) concentration(ppm) in d u c ti o n t im e (m in ) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 388 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure. 9. compare the induction time of pure water agents different concentration of surfactant tween 80. figure.10. compare the pure water storage capacity with and without different concentration of surfactant tween 80. the water moles convert to hydrate during the hydrate growth process was calculated for the binary system and ternary system. figure (11) shows the water conversion increased due to gas consumed because of increasing in the driving force with time. 51 52 53 54 55 56 57 58 59 60 61 1 0 5 10 15 20 25 30 0 10 20 30 40 50 60 pure water 25 ppm 50 ppm 75 ppm 100 ppm pure water 25 ppm 50 ppm 75 ppm 100 ppm s to r a g e c a p a c it y ( v /v ) concentration (ppm) time (min) w a te r c o n v e r si o n % journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 389 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure (11): the water to hydrate conversion as faction with time at different concentrations of tween 80 hydrate growth represented in the figure (12a,b,c,d, and e) for different concentration of tween 80.the growth rate in the presence tween 80 for ternary system increases gradually until reaching the maximum value at 18 minutes in 50ppm tween 80. the rates of growth reduce when time increases, because of the drooping in the driving force with time. as a result of the use of the surfactant, the solubility of the gas increases in the water, causing an increase in the particles of the micro hydrates and thus generates a higher surface area by reducing the contact angle and thus a higher mass transfer rate. the fluctuation in the growth rate is the result of passing through different stages from the beginning of the gas dissolving through the stage of nucleation until it reaches the stage of growth accompanied by a rapid drop in pressure and this can be seen through the bends. the surfactant is one of the effective anti-agglomerates that prevent agglomeration of hydrate crystals that causing less free water to entrap between solid hydrates. figure (12a): the r134a hydrate growth rate against time without tween80 . 0 50 100 150 200 250 300 0 10 20 30 40 50 60 time(min) g r o w th r a te (l /m in ) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 390 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure (12b): the r134a hydrate growth rate against time with 25 ppm of tween80 figure (12c): the r134a hydrate growth rate against time with 50 ppm of tween80 0 50 100 150 200 250 300 350 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 0 10 20 30 40 50 60 time(min) g r o w th r a te (l /m in ) time(min) g r o w th r a te (l /m in ) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 391 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure (12d): the r134a hydrate growth rate against time with 75 ppm of tween80 figure (12e): the r134a hydrate growth rate against time with 100 ppm of tween80 during hydrate nucleation and growth, the apparent rate constant reduces quickly to a constant value then the formation of hydrate is completed. in figure (13) notice the general behavior of kapp is the apparent rate decreases with time and that can be explained when hydrate formed the heat increase due to this phenomena is exothermic that cause the rate to decrease. 0 50 100 150 200 250 300 350 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 0 10 20 30 40 50 60 time(min) g r o w th r a te (l /m in ) time (min) g r o w th r a te (l /m in ) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 392 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure (13): apparent constant versus time during the growth of r143a hydrate at different concentration of tween80. 5.conclusions the effect of the different concentration of the surfactant on the gas hydrates formation of r-134a was observed in terms of improved nucleation of hydrate and hydrate growth rate. the presence of surfactants improves the gas solubility and its spread in the water effectively, as well as to reduce the contact angle and improve contact with the gas-water, which in turn positively affects the rate of formation of hydrates . after using different concentrations of the surfactant 25, 50, 75 and 100 ppm, the following conclusions were reached: (1) in general, tween 80 at different concentrations (25, 50, 75 and 100 ppm) promotes the formation of r-134a gas hydrates effectively. (2) the maximum effect of tween 80 on the induction time of r-134a gas hydrates can be achieved at a concentration of 100 ppm. (3)maximum promotion effect of tween 80 on r-134a hydrate growth rate was achieved at the concentration of 50 ppm. (4)maximum theoretical value of storage capacity is 59.75 v/v at standard condition that is achieved at a concentration of 100 ppm of tween 80. gas separation process in hydrate form increases due to increased hydrate nucleation and increased hydrate growth. desalination, storage and transport have benefited greatly from improved hydrate formation kinetics. 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0 10 20 30 40 50 60 pure water 25 ppm 50 ppm 75 ppm 100 ppm k a p p ( l/ m in .m p a ) time (min) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 393 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. references 1. al-muktar, r.s., al-hemeri, s.t., mahmood, l.w., 2018.study the dissociation enthalpies for r-134a clathrate hydrate in binary and ternary system. al-khuarzmi engineering journal.(under publishing). 2.cassandra petticrew, 2014. an investigation into the use of fluorinated hydrating agents in the desalination of industrial wastewater. chemical engineering thermodynamic stability conditions of clathrate hydrates for refrigerant (r134a or r410a or r507) with mgcl2 aqueous solution, university of kwazulu-natal, durban, south africa, 3.clarke, m.a., and bishnoi, p.r., 2001. measuring and modeling the rate of decomposition of gas hydrates formed from mixtures of methane and ethane. chemical engineering science, 56(16), pp.4715-4724. 4.fuhrhop, j.h. and koning, j., 2007. membranes and molecular assemblies: the synkinetic approach. royal society of chemistry. 5.guo, y., fan, s., guo, k. and chen, y., 2002, may. the storage capacity of methane in hydrate using calcium hypochlorite as additive. in mori. 4th international conference on gas hydrates. yokohama (vol. 1040). 6.han, x., wang, s., chen, x. and liu, f., 2002, may. surfactant accelerates gas hydrate formation. in 4th international conference on gas hydrates, yokohama, japan (pp. 1036-1039). 7.kalogerakis, n., jamaluddin, a.k.m., dholabhai, p.d. and bishnoi, p.r., 1993, january. effect of surfactants on hydrate formation kinetics. in spe international symposium on oilfield chemistry. society of petroleum engineers. 8.klauda, j.b., and sandler, s.i., 2000. a fugacity model for gas hydrate phase equilibria. industrial & engineering chemistry research, 39(9), pp.3377-3386. 9.kumar, a., sakpal, t., linga, p. and kumar, r., 2013. influence of contact medium and surfactants on carbon dioxide clathrate hydrate kinetics. fuel, 105, pp.664-671. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 394 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 10.kumar, a., sakpal, t., linga, p. and kumar, r., 2015. enhanced carbon dioxide hydrate formation kinetics in a fixed bed reactor filled with metallic packing. chemical engineering science, 122, pp.78-85. 11. leporcher, e.m., peytavy, j.l., mollier, y., sjoblom, j. and labes-carrier, c., 1998, january. multiphase transportation: hydrate plugging prevention through crude oil natural surfactants. in spe annual technical conference and exhibition. society of petroleum engineers. 12.lim, y. a.; 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2008. 20.smith, j.m., van ness, hc, abbott, mw, 2001. introduction to chemical engineering thermodynamics. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 395 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 21.sum, a.k., koh, c.a. and sloan, e.d., 2009. clathrate hydrates: from laboratory science to engineering practice. industrial & engineering chemistry research, 48(16), pp.7457-7465. 22.sun, q., guo, x., liu, a., liu, b., huo, y. and chen, g., 2010. experimental study on the separation of ch4 and n2 via hydrate formation in tbab solution. industrial & engineering chemistry research, 50(4), pp.2284-2288. 23.suradkar, y.r. and bhagwat, s.s., 2006. cmc determination of an odd carbon chain surfactant (c13e20) mixed with other surfactants using a spectrophotometric technique. journal of chemical & engineering data, 51(6), pp.2026-2031. 24.torré, j.p., dicharry, c., ricaurte, m., daniel-david, d. and broseta, d., 2011. co2 capture by hydrate formation in quiescent conditions: in search of efficient kinetic additives. energy procedia, 4, pp.621-628. 25. zhang, b.y., qiang, w. and sun, d.l., 2008. effect of surfactant tween on induction time of gas hydrate formation. journal of china university of mining and technology, 18(1), pp.18-21. 26.zhang, h., yao, m., morrison, r.a., and chong, s., 2003. commonly used surfactant, tween 80, improves absorption of p-glycoprotein substrate, digoxin, in rats. archives of pharmacal research, 26(9), pp.768-772. 27.zhong, y. and rogers, r.e., 2000. surfactant effects on gas hydrate formation. chemical engineering science, 55(19), pp.4175-4187. article al-qadisiyah journalforengineering sciences 13 (2020) 055–060 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: methaq.ali2006@gmail.com (methaq a. ali) https://doi.org/10.30772/qjes.v13i1.626 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. implementation of intelligent industrial controller based on fuzzy logic and plc methaq a. ali a*, abbas hussein miry b, tariq m. salman b adepartment of electrical engineering, faculty of engineering, university of al-mustansiriyah, basrah, iraq. bdepartment of electrical engineering, faculty of engineering, university of al-mustansiriyah, baghdad, iraq. a r t i c l e i n f o article history: received 06 january 2020 received in revised form 16 february 2020 accepted 28 february 2020 keywords: iot opc server mqtt plc kayenne. a b s t r a c t the internet of things (iot) makes designing a smart management system is real and easy. the concept of smart management system guarantees a person to monitor, control and manage the system without any waste. water is a key resource and its management is a major issue. the proposed method is iot with the fuzzy controller based system for managing tank water level in rumaila power plant from gas (in southern iraq). the existing system, designed with two electric motor pumps, supplies a storage tank with untreated water from the river for later use in (reverse osmosis) r.o. this system is manual without efficient monitoring and control system. this paper includes two implemented control systems; the classic pid and fuzzy logic with a comparison between them. fuzzy control is simulated first using matlab and then developed by sugeno-based fuzzy algorithm within the plc (programmable logic console) environment. the connection of plc with opc (object process control) server used by the modbus protocol while the sensors connected directly to kayenne platform. using the opc and mqtt, the iot system is built up to publish and subscribe the data from plc and cloud. node mcuesp8266 is used by wireless communication to link the sensors with router. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the internet of things is a smart method used in wide applications in monitoring of transport systems, environment, health, and other industrial and commercial areas. there are three major parts of iot are objects, semantics, oriented vision and the internet which developing communication systems. the iot is a network that includes physical devices or sensors, that sharing software, storage, and internet connectivity which allow these things to record, collection, exchange data and managing it [1]. there are several ways that are suitable to control and monitor industrial systems like scada, plc, the internet of things, wireless sensor networks (wsn), etc. plc employed in industries by various automation systems and applications to improve quality and reliability to decrease production cost. recently, iot is considered as a suitable method for monitoring industrial systems. this includes communication systems in embedded systems to allow devices and (wsn) wireless sensor networks to be linked via the internet or industrial systems to be managed and monitored by mobile devices and laptops[2].iot allows real objects such as sensors and actuators to be conveniently connected to the internet. it provides an easy way to connect the real or physical objects with the gateway when applying wireless communication in the iot system as illustrated in fig.1. in addition, the use of wireless communication can http://qu.edu.iq/ mailto:methaq.ali2006@gmail.com 56 methaq a. ali et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 055–060 reduce a large number of wires and cables and thus reduces the possibility of faults, particularly in huge industrial networks. iot could be performed by applying various communication methods such as zigbee, bluetooth, node-mcu (esp8266) and wan. controllers are regarded as necessary elements in iot because they are used in two matters; the first one is with real things to change it from passive to active (the smart device has singular credentials) or can say it operates like an embedded system. the second one is to serve as the central controller to address the processing and computational of an assigned process and receiving the signals of objects in some of iot arrangements. while in other iot arrangements things or devices linked straight to the internet and computing operations conducted in the cloud.actually, depends on the complexity and importance of the process connecting the things either direct to the cloud or transmitting the datavia the local central controller.the stability and availability of internet services in the application region may be affecting the way of connecting the object to the cloud. this work obtainingthe novelty since it includes; the use of iot infrastructure withplc, which is one of the leading industrial controllers. the second is the use of wireless connection to transfer data from the sensor to the plc. the third is the design of a fuzzy controller algorithm to evaluate the fuzzy within the plc system and accurately control the water level of the tank. it is important to note that as a case study the water level was used to verify the system's operation. thus, it is reasonable to use some changes to the settings to run with any other process such as temperature and pressure. 2. previous studies and research gaps himanshu singh,et. al.[5], developed a prototype for a smart home system to monitor and control some of the home appliances by using iot. they succeed to send data of lighting, sunblind, gas bottle weight sensor and energy consumption meter to the cloud. nodmcu with arduino are employed as hardware. while php programming is used to build the web interface. felipe, et. al.[3], submitted iot system including industrial temperature sensor attached to arduino. the xively platform was employed to monitor the sent data; plc has been used to receive the downloaded data from the cloud platform via the opc server, they also used hmi programmed by using the lab view. shinde, bhgat [2], many common parameters of industry such as d.c-motor, electricity, liquid level based on plc, speed control, and iot color mixer based on plc were monitored by the iot network. in addition to plc, nodmcu was used to relay sensor data to the cloud for wireless communication. antonin gavlas, et. al.[5] suggested iot to monitor and control the manufacturing of a stack of pucks. they employed plc to obtain sensor dataas the main controller. they used the mqtt protocol and (node-red) to connect to two platforms (ibm and ubidots) and then performed a latency comparison. joshi, et. al.[4], iot used to monitor the icrh dac system. they use the (epics) which is the abbreviation of experimentalphysical-industrial-control-system as an interface between device and plc, they use the graphical user interface (gui) and html5 & css to create a web page, and they use the browser opi and cssboy opi to connect the local server with the web page. we were capable of performing iot for the "r.o water" in our paper 3. proposed method the planned structure of device layers consists of five layers; 1sensors layer: this is the first layer in the network representing the things, or in other words, the iot population, and is intended to be the basic level of the iot system. in an industrial iot network, there are some many actuators and sensors that communicate with the machines. that machine usually has different sensors in the industry to track the main parameters related to the output and its healthy condition. the actuator and sensor, each with a microcontroller, are liable for receiving data or managing switches through a predetermined system. the sensor node is a radio-powered microcontroller connected to sensors. they deploying and a self-contained unit that publishes the sensor-generated data. the sensor node has not treated the data locally because it does not have sufficient memory and processing ability. a lower energy wireless communications arrangement is used to send sensor data to the main controller by using the esp8266[6]. in this project, three types of sensors have been applied; these sensors are critical to the prototype development, based on technical requirements and site survey. the electrical motor is the key part of this project in which we need to attach sensors to monitor and control it in order to ensure the system's stability and continuous operation. the practical variables chosen for use are the water level of the tank, the current of the motor and the river water level. the plc-based fluid level control system has been used to maintain and track the water level of the tank and provides real-time indications of the tank and river water level. there are two types of water level sensors used in the project; vl53lox and hc-sr04. two pails of water were added, one for simulating the r.o storage reservoir and the other for simulating the river. for the interlocking of motor activity, the water level sensor of the river is required, due to the lack of this sensor; dc motor can remain in service, although the water level of the river is low or very small. if the water level of the river is very low, it will contribute to the critical activity, as it will decrease the cooling of the electrical motor impeller. this sensor was used to simulate switches, and its controller can adjust the ultrasonic distance sensorhc-sr04 setting. as a result of the low river water level, it is used to turn off the motor and prevent the mixing of water with air bubbles entering the motor pump. actuality, this sensor's failure can result in motor pump vibration, overheating, and mechanical problems. the sensitivity of the ultrasonic sensor is about 1 cm, due to no need for high precision for these measures; it is regarded as adequate sensitivity. the benefit of using figure 1:general layout of proposed system methaq a. ali et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 055–060 57 an ultrasonic sensor is that it measures the river's water level and can allow it to assess the low water level duration during the year and take appropriate preparations using the data collected for a long time. the other pail is r.o collecting reservoir tank because its output value is used for the fuzzy logic algorithm, so the selected sensor needs more accuracy. that is the case; it relies on its output values for error change (ce) and error (e), that's the reason for choosing time of flight distance sensor (t.o.f-vl53lox). the vl53lox's sensitivity is about 3 mm. in this project, the dc current sensor is necessary to allow the operator to monitoring the motor current. it may also be cloud monitoring and warning or trip composing if its value meets the threshold value. this sensor protects an electrical motor coil from the damage caused by the increased current, which leads the coil heat to rise. for this problem, the current sensor ina219 is appropriate for the arduino controller and has the capability to supply power and voltage in addition to the current measurement. the use of the current sensor has another advantage in the issue of fault analysis where it is possible to use the reserved history of the current motor to define the circumstances of faults and to obtain the precautions to limit future faults. 2network layer is essential for the iot system because it is the layer liable for connecting physical objects employing modbus tcp/ip which is the leading iot protocol. tcp / ip (transmission— control— protocol / internet—protocol) started a long time ago, but its position as the predominant communication protocol up to date has persisted. this is because of its wonderful capability to ensure reliable data communication across various media. tcp / ip protocol package that makes ip data to cross-unsecured networks such as traditional dial-ups and serial longdistance connections with a reasonable degree of reliability. tcp/ip submits ip with the lost packets detection task by make sequence for each packet—likewise to allow the recipient to re-order the streams packet according to packet sequence numbers. this is an example to explain the operation of ip is a web client transmitting a url request to a web server. the client searches first to find the ip address for the given url via dns (dynamic-name-server) and then contact the server utilizes the registered ip address, which matches to the url [7]. the topology or structure of the iot system submitted is a star topology. the iot device in this topology is directly linked to a convenient gateway that upstream transfers the information from the associated devices. the standard for wireless wi-fi network used is ieee 802.11a / b / g / n. the communication classification used for devices of proposed iot system is 802.11g and for power consumption causes, the low-cost wi-fi microchip with full tcp/ip stack esp8266 chip has been adopted. 3processing layer: there are two processing parts; one in the main local controller, or the programmable logic control (plc), that looks at the complicated processing described by fuzzy control. the other one of processing is doing using the cloud platforms that represent the complete system's monitoring, data collection and control, including saving events and alarms by cloud computing using the cayenne platforms. the fuzzy control method is used to manage the presented process as the classic control system such as pid has a lower efficiency than the fuzzy system for several reasons such as overshot, increased settling time, and a higher steady-state error as described in the following section. moreover, the use of conventional controllers leads to higher energy consumption [8]. there are two ways to store events and alarms, first in opc server (kep server ex) by using the opc server events and alarm software. the database was stored on the local computer's hard disk using my sql. the other way is to use the cloud using cayenne 's dashboard. events and alarms play a necessary role for analysis. it can be used as historian information for maintenance engineers to investigate the defects that happen in the working system. 4gateway layer: it can be described as a software application or a real device that operates with the cloud as the point of contact between controllers, sensors and smart devices. the advantage of iot's gateway is that it can provide extra security between iot and local devices for the transported data. in this situation, setting up the network based on current devices is a major challenge because devices from various companies and at different technical rates do not communicate with the same language. usually the solution takes a long time. a smart gate way is defined that combines communications between different information sources and passes data to the proper recipients. the iot gateway, which able to receive and process information from a plc, and then store the processed data in the cloud platform. the individual devices are remotely controlled by web applications. opc requirements define the communication and interfaces of opc servers as a standard for the interoperability of industrial machine applications. the specification released by opc framework for access to data describes costume frameworks for control and other information that the main issue is to attempt to deliver data from local devices in real-time. the costume interfaces are included in the opc server, while the gui is optional. so long as device interfacing and customers agree with the specifications correctly, high-efficiency data transmission can be ensured [3]. mqtt is a very simple and lightweight message protocol. it is based on a publish-subscribe to be accessible and easy to run with a single server capable of serving hundreds of remote clients. [9]. 5cloud layer: in this sense, cloud means a large number of network-connected devices that are highly dependent on virtual computing when providing their service where any of these computers is interconnected with multiple virtual machine tasks to achieve cost-minimization. cloud computing solves issues related to remote storage of data, such as the expense and ability to record large amounts of data. cloud companies also implementing and offering analytical applications capable of handling huge amounts of data. such techniques are growing and being increasingly available, and this seems to be the main point. [10]. cayenne is the first iot application creator to drag and drop in the world to enable developers, engineers and designers to easily test and upload their created connected device. cayenne is aimed at helping users create designs for the internet of things and then put them into operation. the cayenne platform has several major components: mobile apps – monitoring and controlling your iot projects remotely from android or ios applications. online dashboard – use adjustable widgets for displaying info, setting rules, arranging activities, etc. 4. system implementation the water intake is considered an industrial system so that more care is needed to provide proper devices for this task. more interesting things to be found in the chosen products are reliability and accuracy. the central controller selected for the framework is from lsis manufacture, plc with 12 digital outputs and 16 digital inputs and 2 analog outputs as well as a communication module. as this work would operate in practice, the condition of the analog input or output element can be used for current or voltage, and we make the necessary work arrangement for the industrial facility to protect it from moisture and dust, such as including the instruments in the correct pvc frame. local control was introduced as shown in fig. 2 by incorporating a selector switch to switch between auto and manual operation and push-buttons. for the implementation of this control, four digital inputs and three digital outputs and finally, one analog output are used. 58 methaq a. ali et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 055–060 the selector switch location on "auto" actually means the level of iot controlling where the iot was used for remote control in addition to computation and monitoring. there are two 24v power supplies in the panel one for dc motor 24v and the other for plc. the process in the system is designed by fuzzy control method. the dc-to-dc convertor working as an interface between plc process output and electrical motor. fig. 3 represents the flow chart of the water level control algorithm. the output of plc (0~5v) is supplied to arduino analog input a0 which processed by arduino to obtain pwm at the output. the pwm signal is supplied to dc drive that in turn produce scaled output (0-24v) capable to control the speed of dc motor. this was done by using the mapping statement in c++ code; input= map (ard input, 0, 1023,0, 255); dc drive the signal of pwm applies directly to the mosfets electronic circuit with a maximum capacity of 4a and an output dc voltage of 0 to 24v. for reliable wireless data transmission between sensors and plc, the mcu-esp8266 chip node is used. to secure the ethernet connection to the plc and provide the devices with the internet, a router device is mounted at the edge of the panel. the plc is connected to a router and all local sensors using the modbus protocol. to design pid controller a pid auto-tuning and pid function blocks have been created in the plc ladder diagram according to the following setting that obtained by using auto-tuning facility available in the plc: set point=20cm, cyclic time= 100msec the pid parameters are; kp=187, ti= 1183, td=295. a fuzzy algorithm with sugeno rules was developed using (structure text) st to execute the process of fuzzy within the plc. seven memberships were selected for both error (e) and changeoferror (ce) in order to get an accurate and high-performance fuzzy system see table 1. the rising and falling edges of a timer have been used for taking the sample of water level and producing the e and ce as a result. the ultrasonic water level output is used to get the error signal in real-time as below: e:=set_value water_level fig.4 illustratethe marking of memberships, error memberships and change of error (ce). enb[1]:=-10.8; enb[0]:=-7.2; enm[0]:=-10.8; enm[1]:=-7.2; enm[2]:=-3.6; the above two statements are an example for defining of two membership (nb&nm) of error. the used fuzzy rules based onthe sugeno approach. as a result of the membership functions of the rule, sugeno utilized the singleton. a singleton, or merely a fuzzy singleton, is a fuzzy collection as a membership form that is zero everywhere excluding that unity will be at a specific point in the universe of discourse. [11]. the fuzzy logic output consists of "11" single spikes from (-1) to (1) increase by 0.2. the following statements are an example of sugeno rule programmed in (structure text) st; figure 2: prototype control panel figure error! no text of specified style in document.3: fuzzy process flow chart figure 4: (a) error (b) change of error (ce) memberships (c) sugeno output singleton methaq a. ali et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 055–060 59 wi(0,0):=-1; wi(0,1):=-1; wi(0,2):=-0.8; wi(0,3):=-0.6; wi(0,4):=-0.4; wi(0,5):=-0.2; wi(0,6):=0; wi' is a matrix abbreviated form named weight matrix that is assigned to the matrix of two-dimension of the weight for the inference level. we must write 49 sentences to accommodate all rules as shown in table.1, which includes 49 rules. table (1) sugino rules e ce nb(0) nm(1) ns(2) z(3) ps(4) pm(5) pb(6) nb(0) -1 -1 -0.8 -0.6 -0.4 -0.2 0 nm(1) -1 -0.8 -0.6 -0.4 -0.2 0 0.2 ns(2) -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 z(3) -0.6 -0.4 -0.2 0 0.2 0.4 0.6 ps(4) -0.4 -0.2 0 0.2 0.4 0.6 0.8 pm(5) -0.2 0 0.2 0.4 0.6 0.8 1 pb(6) 0 0.2 0.4 0.6 0.8 1 1 although the signal of error changes over time, it is assumed that "e" will be on any of the member ships of error, so it is important to check the existence of error signal on each member ship and precise value within the member ship. actually, there is one problem that needs to be addressed in particular before the system operates in the real world. the pump is worked within 24vdc and the passing current is increased if the applied voltage begins from zero. when the voltage applied to the driver is less than 6.0 v, the problem appears; the pump cannot be started correctly. to solve this problem, the fuzzy controller should be designed in such a way that it does not supply less than 6.0v. the controller should inspect the error value if the dc drive output is less than 6v (fuzzy output 1250mv as a scaled output sent as input to d / a converter), it will consider the output to zero and the system reaches the desired set point. such action was taken to protect the pump against any damage. 5. results and analysis using the mat lab fuzzy tool, this method is simulated and delivers the result shown in fig.5. the figure explains that the maximum value of the fuzzy output is set to 20 cm if the error is 10.8 cm and the ce is 1. table 2 reveals that the efficiency of fuzzy is higher than the conventional pid controller. whereas fuzzy's transient time, settling time, and fuzzy's integral time absolute error (itae) in fuzzyis less than pid, irrespective of the slight change (iae) integral absolute error that has no substantial impact on performance. therefore, the fuzzy controller alternative is the correct choice. the system test was done; it yields results in real-time. however, the comparison between the results of the plc output in realtime and mat lab shows that the outcomes of the fuzzy system applied are similar to mat lab outcomes as displayed in fig.6, which means that the suggested working algorithm is correct. monitoring and controlling from the cayenne platform is carried out successfully with some delay in reading from plc to cloud. it delays because the cayenne platform sets the data update refresh rate about 10sec and with some latency in that platform's server. a real time comparison curves for both pid and fuzzy is combined in a same sketch as shown in fig. 7 a simple dashboard has been performed to visual representation of network interface control. in fact, as shown in fig. 8, this interface can be utilized to control the electrical motor. the variations in system values have been observed if a certain value exceeds or below a defined threshold, a warning signal is sent to an e-mail or a text message is sent to a mobile device. in fact, this feature represents the computational in the cloud. through moving data to cayenne's cloud platform, the data recovery can be accomplished. from the above scenario, it is best to use a business network from a security perspective, as well as to reduce data processing's slow latency. eventually, the plan runs well and performs all the necessary functions in the design. figure 7: comparison between pid and fuzzy figure 6: comparison between plc and matlabat ce=0, 1, -1 figure 5: e and ce output for the fuzzy 3d surface plot 60 methaq a. ali et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 055–060 6. conclusion this work provided a simulation of the industrial water intake process of the plc-controlled r.o type, which could also be monitored and managed using the iot. wireless communication has been used in the industry with many benefits, such as reducing the amount of cables, reducing the risk of accidents and simply carrying out repairs. iot may serve as a supplement to existing control systems in order to achieve ideality for industrial systems. at any time and from anywhere in the world, it has a major role to play in remote controlling the working systems, and this will improve system stability. a contrast of classical (pid) and fuzzy (artificial intelligence) control systems reveals that fuzzy's performance is better than the classic pid controller. in addition, fuzzy provides a more efficient, precise and reliable control system and led to power-saving. events and alarms history is using the cayenne api to back up, sms and email messages have been practically received by mobile and email when an alarm signal occurs. iot is important to support the maintenance where experts viewing the events, alarms, and tracking the data trends remotely by using the cloud services to utilize them in faults analytics and give proper solutions. this research has the innovation of combining three important issues: using wireless technology to send sensor data to the plc, using iot technology with plc, and designing an algorithm to run the fuzzy controller in the plc system. the specification submitted was entirely flexible to allow for more or less i / o commands according to the needs of the industry. acknowledgement the authors greatly acknowledge the electricity production for south region/al-rumaila gas power plant, for the help and support in finishing this research paper. references [1] j. rezazadeh, k. sandrasegaran, and x. kong, “a location-based smart shopping system with iot technology,” ieee world forum internet things, wf-iot 2018 proc., vol. 2018-janua, pp. 748–753, 2018. [2] k. s. shinde and p. h. bhagat, “industrial process monitoring using lot,” proc. int. conf. iot soc. mobile, anal. cloud, i-smac 2017, pp. 38–42, 2016. [3] f. corso, y. camargo, and l. ramirez, “wireless sensor system according to the concept of iot -internet of things-,” proc. 2014 int. conf. comput. sci. comput. intell. csci 2014, vol. 1, pp. 52–58, 2014. [4] r. joshi, h. m. jadav, a. mali, and s. v. kulkarni, “iot application for real-time monitor of plc data using epics,” 2016 int. conf. internet things appl. iota 2016, pp. 68–72, 2016. [5] h. singh, v. pallagani, v. khandelwal, and u. venkanna, “iot based smart home automation system using sensor node,” proc. 4th ieee int. conf. recent adv. inf. technol. rait 2018, pp. 1–5, 2018. [6] a. al-fuqaha, “al-fa-internet of things: a survey on enabling technologies, protocols, and applications,” ieee commun. surv. tutorials (accepted publ., vol. 1, no. 2, pp. 2347–2376, 2013. [7] m. b. community, “modbus application protocol,” berlin, 1, 2012. [8] l. de microinformatique and j. godjevac, “comparison between pid and fuzzy control,” p. 23, 2007. [9] c. yoon, m. huh, s. g. kang, j. park, and c. lee, “implement smart farm with iot technology,” int. conf. adv. commun. technol. icact, vol. 2018-febru, pp. 749–752, 2018. [10] zhihao ling, weibin chen, and jinshou yu, “research and implementation of opc server based on data access specification,” pp. 1475–1478, 2004. [11] j. r. mahmood, r. s. ali, h. migdadi, r. a. abd-alhameed, and e. m. ibrahim, “development of educational fuzzy control laboratory using plc and hmi,” 2015 internet technol. appl. ita 2015 proc. 6th int. conf., no. september, pp. 383–387, 2015. figure 8: kayenne designed dashboard 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 دراسة مقارنة حول جدوى استخدام الجص بالطريقة التقليدية وطريقة الرش بالماكنة منتظر جبار طاهر* دمحم نعمه الغانمي** ايمن جميل كاظم*** 5102 شباط 50ُقبل في 5102 تشرين االول 8أستلم الخالصة الهدف من الدراسه هو مقارنة جدوى استخدام طريقة االنهاء التقليديه بالجص االعتيادي والفني )البورق( مع من خالل عمل دراسة تحليليه لكلف كل طريقه )مواد وعمالة ... (knauf)طريقة الرش بالماكنه للجص نوع الخ( ومقارنتها، وكذلك عمل دراسة مقارنة حول المدة الزمنية الالزمة النجاز العمل وانعكاسها على سرعة العمل، تم لمختبريه االخذ بنظر االعتبار جودة العمل والمواد المستخدمه في كال الطريقتين من خالل اجراء الفحوصات ا الالزمه للمواد ونوعية االنتاج. والدراسة التي اجريت تبين من خالل البحث بأن استخدام طريقة الرش بالماكنه لمادة ( اقل كلفة ومدة انجاز وافضل جوده انتاج مقارنة مع طريقة االنهاء بالجص بالطريقة knaufالجص نوع ) انعكاسا ايجابيا على المشاريع من حيث الكلف وزمن االنجاز التقليديه، وتم التوصيه باعتمادها لما توفره من والنوعية. الكلفة. (،knauf)الجص الفني ، جص الجص العادي ،دراسة الجدوى , الرئيسية: الكلمات a comparative study on the feasibility of the use of finishing gypsum plaster in the traditional manner and method of spraying with machine muntadher j. taher* mohammed n. al – ghanimi** aymen j. kadhim*** *asst. lec. & lead supervisor eng. / imam hussein holy shrine / karbala / montazar.88.kut@gmail.com. **asst. lec./ dep. of civil eng./ college of eng. / uni. of karbala / engmohammed_83@yahoo.com. *** asst. lec./ dep. of civil eng./ college of eng. / uni. of karbala / aymanalsaad2@gmail.com. mailto:engmohammed_83@yahoo.com mailto:aymanalsaad2@gmail.com 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 abstract the aim of the study is to compare the feasibility of using the method of traditional finishing by normal and technical gypsum plaster with the method of spraying with machine for plaster type (knauf) through the work of an analytical study of the cost of each method (materials and labor ... etc.) and compare them, as well as the work of a comparative study on the necessary time to complete the work and its impacts on the working speed. it was taking into consideration the quality of work and materials used in both methods by conducting laboratory tests required for materials and production quality. through research and study shows that the use of method of spraying with machine for plaster type (knauf) less the cost and achievement duration and best production quality compared with the method of traditional finishing by gypsum plaster, and has been recommended for adoption because they provide a reflection positively on the project in terms of cost, achievement time and quality. keywords: feasibility study, normal gypsum, technical gypsum, knauf gypsum, cost. المقدمة -0 انطالقًا من اهمية تعزيز مواد االنشاء بإيجاد بدائل لها تكون قليلة الكلفة وسريعة التنفيذ مع الحفاظ على اتقان الجودة و النوعية التي تلبي المتطلبات الفنية للمواصفات القياسية، البد من تحليل كلف هذه البدائل واجراء المقارنات من جهة أخرى التأكد من الجدوى االقتصادية للبدائل المطروحة دون بينها وبين ما هو متبع وتقليدي من جهة و الركون إلى الكلفة الحالية التي قد تكون ظاهريًا أقل من غيرها ولكنها ليست كذلك من الناحية االقتصادية. يتضمن صول إلى نتائج هذا البحث حساب ومقارنة للبدائل المتاحة من حيث الكلف ومدة التنفيذ وكمية ونوعية االنتاج للو .(1)تساعد في اتخاذ القرار لتبني البديل المقترح ان الجبس النقي هو شفاف مائل الى البياض ، لكن في بعض األحيان يحوي على الشوائب فيكون ذا الوان مثل خين وعندما يتم تس caso4 • 2h2oالرمادي والبني، أو الوردي. االسم الكيميائي هو كبريتات الكالسيوم المائية ( الذي يسمى caso4 • ½h2o) hemihydrateالجبس فإنه يفقد حوالي ثالثة ارباع من مياهه ويصبح الجص، وكذلك يمكن ان يتكون بهذه الصورة في الطبيعة ايضًا. حيث يتم خلط هذا المسحوق مع الماء لتكوين بخر الماء منها . ويستخدم الجص عجينة أو مونة، وبعد ذلك سوف تجف وتصبح صلبة نتيجة اكتسابها المقاومة وت كمونة بناء وكذلك في االنهاءات ) الجص العادي ، البورق ، الجص الفني ( وال تستخدم االالت في العمل عند متطلبات المواصفة مطابقته لمع وجوب (2)استخدامه كطبقة انهاء وانما تستعمل الطرق التقليدية اليدوية في العمل .(3) 1822( لسنة 22العراقية القياسية رقم ) 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 يستعمل بطريقة الرش بالماكنة على اغلب االسطح (knauf) اما النوع الثاني في هذا البحث هو جص نوع ويوفر لصق جيد جدا وهو بديل فعال للغاية في مساحات العمل المفتوحة عن الجص التقليدي عند استعماله في هيئة طبقات واقل شقوق وكما أن االنهاء فيها يكون ذا جودة انهاء للجدران والسقوف، كونه أقل عرضة للتكون على . الذي تنطبق عليه المواصفات االوربية و (4)عالية وايضا تتوفر االالت المناسبة في استخدام الرش الميكانيكي .(6( و )5) bs en 13279-2:2014و bs en 998-1:2010متطلبات المواصفة البريطانية الهدف من البحث -5 الهدف من البحث هو اجراء دراسة مقارنة عملية بين استخدام االنهاء بالطرق التقليدية التي تمثل االنهاء بطبقة ان جامعة كربالء( والطريقة الثانية هي بالرش -من الجص ثم تليها طبقة البياض بالبورق )بناية عمادة كلية الهندسة االمانة العامة –مجمع مدارس االيتام النموذجي )مشروع (knauf) بالماكنة لنوع من الجص هو جص نوع بالتالي معرفة جدوى الطريقه التي توفر بدائل لمواد للعتبة الحسينية المقدسة( الذي يعتبر االنهاء به مباشرة، و سريعة التنفيذ مع الحفاظ على النوعية المثبتة ضمن المواصفات. االنشاء اقل كلفة و تحليل الكلف -3 لغرض إجراء مقارنة لكلفة البدائل وتحليل سعر المفردات الداخله في تنفيذ اعمال البياض فقد تم استخراج قيمة كل ( 1وكما موضح في الجدول رقم ) (7)فقره باالعتماد على الدليل القياسي لتحليل االسعار لقطاع البناء واالنشاءات ناه ال يمثل اسعار ثابته نظرا لتقلبات االسعار, فاسعار المواد ان تحليل االسعار في الجدول اد ،(2والجدول رقم ) كما ان موقع المشروع يؤثر ،اضافة الى عوامل العرض والطلب ،وت بحسب مواصفات المواد ومناشئهامثال تتفا .د واجور االليات وااليدي العاملهبالزياده والنقصان على اسعار الموا البديل األول -3-0 لكل متر مربع باإلعتماد على كلفة المواد المستخدمة و كلفة االيدي االنهاء وفق الطريقه التقليديهتحليل كلف إن مع امكانية (دينار 11.111)العاملة و معدل االنتاجية لكل يوم عمل، تبين ان كلفة المتر المربع الواحد تساوي هرين ثالثة عمال نقل وتجهيز المواد و كما لكل مجموعة متكاملة من عامل ماهر و عاملين غير ما (2م12)انتاج .(1جدول رقم )مبين في ال البديل الثاني -3-5 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 لكل متر مربع باإلعتماد على كلفة المواد المستخدمة و كلفة رش بالماكنةتحليل كلف االنهاء وفق طريقه الإن مع (دينار 7.511)الواحد تساوي االيدي العاملة و معدل االنتاجية لكل يوم عمل، تبين ان كلفة المتر المربع لكل مجموعة متكاملة من عامل ماهر و عاملين غير ماهرين ثالثة عمال نقل وتجهيز (2م151)امكانية انتاج .(2جدول رقم )المواد و كما مبين في ال مقارنة الكلف -4 المباشرة تتأثر كثيرًا بكلف المواد ، و احتساب كلفها المباشرة. مع العلم ان الكلف بعد ان تم اختيار نماذج االنهاء ( الكلف التي تم 3الداخلة واأليدي العاملة ذات التأثير المباشر في اتمام الفقره االنشائيه، ويوضح الجدول رقم ) تسابها لكل من البدائل المختارة.اح ائج العملية للمواقع المذكورة انفًا لقد تم تخمين المواد األولية المطلوبة ألنجاز فقرة االنهاء بشكل دقيق وتم مقارنة النت 2115والتي هي قيد األنشاء وفي فقرة انهاء الجدران والسقف واعتمادًا على سعر السوق في الربع االول من عام )للمواد األولية واأليدي العاملة( والتي يمكن اعتمادها في اتخاذ القرار ألختيار البديل األفضل ومن خالل مالحظة ان البديل الثاني ذو كلفة منخفضة مقارنة بالبديل األول. الجدول يتضح مقارنة مدة التنفيذ -2 من خالل األجراءات العملية التي تم تنفيذها والتي شملت كل من التجارب العملية واألطالع على بعض المواقع الميدانية التي تعتمد كل من البديلين األول والثاني ألنجاز فقرة االنهاء ومناقشة ذوي الخبرة واألختصاص في فقرة بالبديلين األول والثاني، واعتمادًا على النتائج الموضحة القطاعين العام والخاص لتحديد المدة الالزمة لتنفيذ كل (, لذا فان المدة التي تستغرقها عملية تنفيذ االنهاء بالبديل الثاني اقل من المده للبديل االول 3في الجدول رقم ) التالي توفير الكثير من وذلك لسهولة تنفيذ البديل الثاني واالنتاجية الكبيرة للبديل الثاني مقارنة بالبديل االول وب الوقت. مقارنة جودة االنتاج -2 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 :(2)تكمن اهمية ضبط جودة االنتاج في زيادة االنتاجية وذلك من خالل زيادة المخرجات باستخدام نفس المدخالت من مواد وعمال ومكائن . -1 االستغالل االمثل لوقت العمل . -2 النتاج المنتج مما يسبب في خفض الكلفة وارتفاع خفض كلفة المنتج من خالل اختصار العمل المبذول -3 االنتاجية . ويعطيها ارتفاع مستوى الجودة وتقليل المرفوض االمر الذي يؤدي الى تحسين الموقع االجتماعي للمنشأة -4 موقعًا تنافسيًا جيدًا . البديلين االول والثاني الجل التحقق من جودة نماذج البحث والتي تمتاز بما سبق ذكره تم اختبار نماذج من وذلك لدراسة هذه النماذج عبر اجراء اختبارات وفحوصات مختبرية واجراء الحسابات الالزمة للوصول الى النموذج االفضل الذي تتوفر فيه المتطلبات التي تحقق الهدف من هذا البحث. البرنامج العملي -7 للمواصفات لكل بديل.تم اخذ نماذج لغرض اجراء الفحوصات المطلوبة ومطابقتها اوال: البديل االول ( 52رقم )ان نتائج الفحوصات للبديل االول بالطريقة التقليدية يعتمد على متطلبات المواصفة العراقية القياسية بعد و(، 5كما في الجدول رقم )وكيميائية ( 4كما في الجدول رقم ) وتصنفها الى متطلبات فيزيائية 0822لسنة الفيزيائية و المواصفات للجص المستعمل لالنهاء مع طبقة البورق كانت النتائج العملية للفحوصاتاستعراض ( على التوالي.7( و )6ولين رقم )كما مبينة في الجد الكميائية و ثانيا: البديل الثاني ا مبينة في الصورة ( و كمmucoنوع ) الرش بالماكنة ان نتائج الفحوصات للبديل الثاني بالطريقة الميكانيكية ) bs en 13279-2:2014و bs en 998-1:2010متطلبات المواصفة البريطانية ( يعتمد على(1رقم ) المستعمل لالنهاء كانت النتائج (knauf)بعد استعراض المواصفات للجص نوع و (،2رقم )والمبينة في الجدول ( على التوالي.11( و )8ولين رقم )كما مبينة في الجد الفيزيائية و الكميائية و العملية للفحوصات للفحوصات 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 االستنتاجات -2 واستعمال الطريقة التقليدية باالنهاء بالجص تليها طبقة البياض بالبورق )البديل االول ( ،تم اختيار نماذج االنهاء لداخله في تم تحليل سعر المفردات ا ،الذي يمثل البديل الثاني و knauf)واستعمال الرش بالماكنة للجص نوع ) ومن مالحظة كمية االنتاج لكل طريقة من خالل األجراءات العملية التي تم تنفيذها والتي ،تنفيذ اعمال كل طريقه التي بينت مطابقة نتائج شملت كل من التجارب العملية على المواد المستخدمه في انهاء الجدران والسقوف و ( والذي يبين(knauf قت تماسك كبير للبديل الثاني نوعت القياسيه و الحصول على و فحص النماذج للمواصفا ،متطلبات اللبخ من خلط ورش وتعديلبان اللبخ بالرش له قابلية تشغيل عالية وهذا يوفر الوقت الكافي الكمال لطريقه االولى التقليديها وبذلك فان طريقه الرش بالماكنه مجديه اكثر من .على مقدار االنتاج ايضاً وينعكس ذلك .المطلوبةمن ناحية التوفير في الكلفة والسرعه في التنفيذ مع الحفاظ على النوعية التوصيات -8 اختبار العديد من المواد لالنواع المتوفرة في االسواق المحلية المستخدمة في االنهاء بالجص بأستخدام الرش والكيميائية وبنماذج عديدة ليتم اعتمادها .بالماكنة واجراء االختبارات الفيزيائية . أعتماد هذه المواد ومواصفاتها ضمن المواصفة العراقية لكونها تفتقر الى مثل هذه االنواع في المشاريع االنشائيه بدال من الطريقة التقليدية knauf) طريقة الرش بالماكنه للجص نوع )اعتماد .لفة والمدة والنوعيةايجابية على الكبالجص والبورق لما لها من انعكاسات المصادر i. ,"الربيعي، سعاد ناصر، "دراسة جدوى إنتاج واستخدام وحدات خرسانية لسقوف أبنية سكنية رخيصة الكلفة .2114رسالة ماجستير، الجامعة التكنولوجية، ii. donald w. olson, "gypsum", 2001. iii. 0822( لسنة 52رقم ) )الجص لالغراض البنائية( متطلبات المواصفة العراقية القياسية iv. (www.knauf.co.uk , www.knauf.ie knauf plasters full range of hand and ) machine applied plasters (2012). http://www.knauf.co.uk/ http://www.knauf.ie/ 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 v. bs en 998-1:2010 " specification for mortar for masonry", part 1: rendering and plastering mortar. vi. bs en 13279-2:2014 "gypsum binders and gypsum plasters", part 2: test methods. vii. الدليل القياسي لتحليل االسعار لقطاع البناء واالنشاءات "، الجزء االول / االعمال المدنيه ، جمهورية " .2114هيئه العامة للمباني ، العراق، وزارة االعمار واالسكان / ال viii. الجامعة –قصيرة ، انور نعيم واخرون ، " االدارة واالقتصاد الهندسي " ،وزارة التعليم العالي والبحث العلمي .1881التكنولوجية , .لتقليديةطريقه االتحليل كلف االنهاء وفق :(0جدول رقم ) (2الوحده )م اعمال البياض ت جص + بورك + ماء(المواد : ) اوال الجص : -1 2كغم / م 25الكميه المطلوبه = 2كغم / م 1.25% = 5نسبة الضائعات * السعر )دينار / كغم( 2كغم / م 26.25الكلفه = البورك : -2 2كغم / م 3.5الكميه المطلوبه = 2كغم / م 1.175% = 5نسبة الضائعات * السعر )دينار / كغم( 2كغم / م 3.675الكلفه = ماء الخلط : -3 كلفة الماء المطلوبه : ( 3+ 5+ 0المجموع = ) 2دينار / م 1611 2دينار / م 811 2دينار / م 511 ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ 5دينار / م 3111 : العمل ثانيا عامل غير ماهر ( 2العماله المطلوبه ) عامل ماهر + 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 1اجرة العامل الماهر عدد/ -1 2اجرة العامل غير الماهر عدد / -2 3اجرة النقل عدد / -3 تضاف اجور عدد ومستلزمات العمل ) سقاالت, مساطر -4 المنيوم , الواح خشب , مالج , قبان ...... الخ ( (4+3+5+0مجموع كلف العماله =) دينار / يوم 75111 دينار / يوم 51111 دينار / يوم 15111 دينار / يوم 5111 ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ دينار / يوم 042111 يوم \ 2م 12= االنتاجيه ثالثا االنتاجيه ( \الكلفه = اوال + ) ثانيا 5دينار/ م 00111 .تحليل كلف االنهاء وفق طريقه الرش بالماكنه :(5دول رقم )ج (2الوحده )م اعمال البياض ت *knauf)المواد : )الجص نوع اوال الجص : -11 2كغم / م 31الكميه المطلوبه = 2كغم / م1.5% = 5نسبة الضائعات دينار 5611كغم( = 31كلفة العبوة ) دينار 127,5كلفة الكيلو غرام = السعر× الكلفه = الكمية ( =31 +1,5 × )127,5 ماء الخلط : -11 كلفة الماء المطلوبه : (5+ 0المجموع = ) 2دينار / م 5811 2دينار / م 511 ـــــــــــــــــــــــــــــــــــــ 5دينار / م 2411 العمل : ثانيا عامل غير ماهر ( 2العماله المطلوبه ) عامل ماهر + 1اجرة العامل الماهر عدد/ -1 دينار / يوم 75111 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 2اجرة العامل غير الماهر عدد / -2 3اجرة النقل عدد / -3 تضاف اجور عدد ومستلزمات العمل ) ماكنة رش , -4 سقاالت, مساطر المنيوم , قبان ...... الخ ( (4+3+5+0مجموع كلف العماله =) دينار / يوم 51111 دينار / يوم 15111 دينار / يوم 25111 ـــــــــــــــــــــــــــــــــ دينار / يوم 022111 يوم \ 2م 151االنتاجيه** = ثالثا االنتاجيه ( \الكلفه = اوال + ) ثانيا 5دينار / م 7211 ( سم.3 – 2.5* االنهاء بطبقة واحدة وبسمك ) ** باالعتماد على معدل المراقبة اليويمة. .كلف البدائلمقارنة :(3جدول رقم ) (5مجموع الكلف )دينار/م / )يوم(5االنتاجيه م وصف البديل 11111 12 األول 7511 151 الثاني .1822( لسنة 22لمواصفة العراقية القياسية رقم )ل المتطلبات الفيزيائية :(4جدول رقم ) دقيقة عند استخدامه للعقادة . 15*يجب ان اليزيد وقت التماسك عن الجص الفني البورق الجص االعتيادي الخاصية ت 1 النعومة )%( ملم عن 1.12قياس 16على منخل رقم اليزيد المتبقي 5 صفر 2 20-12 25-2 *25-2 وقت التماسك )دقيق( 2 6 5 3 ( التقل عن2قوة التحمل الضغط )نيوتن/ملم 3 2 1.5 -----( اليقل عن2معاير الكسر )نيوتن /ملم 4 5 5 -----قوة الصالدة )ملم( اليزيد قطر الثلمة للكرة الساقطة عن 5 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 12 .1822( لسنة 22لمواصفة العراقية القياسية رقم )ل المتطلبات الكيميائية :(2جدول رقم ) الفحوصات الفيزيائية.نتائج :(2جدول رقم ) الجص الفني البورق الجص االعتيادي الخاصية ت 41 45 35 % التقل عن so3نسبة 1 27 31 25 % التقل عن caoنسبة 2 1.25 1.25 1.25 االمالح الذائبة وامالح المغنيسيوم )%( التزيد عن 3 8اليزيد عن 9 4 8اليزيد عن الماء المتحد )%( 4 8اليزيد عن ----- 8اليزيد عن الفقدان بالحرق )%( اليزيد عن 5 -----5 ----نسبة الشوائب )%( التتجاوز 6 البورق الجص االعتيادي الخاصية ت صفر 6.2 16النعومة )%( المتبقي على منخل رقم 1 18 22 وقت التماسك )دقيقة( 2 5.6 3.1 ( 2قوة التحمل الضغط )نيوتن/ملم 3 1.7 -----( 2معاير الكسر )نيوتن /ملم 4 4.3 -----قوة الصالدة )ملم( 5 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 .الكيميائيةنتائج الفحوصات :(7جدول رقم ) .bs en 13279-2:2014و bs en 998-1:2010متطلبات المواصفة البريطانية :(2رقم )جدول البورق الجص االعتيادي الخاصية ت 51 38 % التقل عن so3نسبة 1 34 26.8 % التقل عن caoنسبة 2 1.21 1.12 االمالح الذائبة وامالح المغنيسيوم )%( التزيد عن 3 2.1 7.2 الماء المتحد )%( 4 ----2.4 الفقدان بالحرق )%( اليزيد عن 5 3.4 ----نسبة الشوائب )%( التتجاوز 6 المواصفة الخاصية ت 51 وقت التماسك ) دقيقة( اليقل عن 1 4-3 وقت الجفاف )ساعة( 2 5 – 1.5 ( التقل عن2قوة التحمل الضغط )نيوتن/ملم 3 2 ( اليقل عن2معاير الكسر )نيوتن /ملم 4 -----(2صالبة السطح )نيوتن/ملم 5 2.5 ( اليقل عن 2قوة االلتصاق )نيوتن /ملم 6 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 .knauf)لمادة ال ) نتائج الفحوصات الفيزيائية :(8جدول رقم ) .knauf)لمادة ال ) نتائج الفحوصات الكيميائية :(01جدول رقم ) .الماكنة المستخدمة في البديل الثاني :(0صورة رقم ) نتيجة الفحص الخاصية ت 75 وقت التماسك ) دقيقة( 1 3.5 وقت الجفاف )ساعة( 2 6.5 ( 2قوة التحمل الضغط )نيوتن/ملم 3 2.4 ( 2معاير الكسر )نيوتن /ملم 4 نتيجة الفحص الخاصية ت 44 % التقل عن so3نسبة 1 22 % التقل عن caoنسبة 2 1.215 االمالح الذائبة وامالح المغنيسيوم )%( التزيد عن 3 11 الماء المتحد )%( 4 7.2 الفقدان بالحرق )%( اليزيد عن 5 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 دراسة االمكانات التنموية الستثمار المياه الجوفية في محافظة النجف االشرف م.م. زينب ديكان عباس الكالبي قسم التخطيط البيئي –كلية التخطيط العمراني/ جامعة الكوفة ماجستير هندسة موارد مائية 5102كانون الثاني 30ُقبل في 5102تشرين االول 22أستلم الخالصة تعد المياه الجوفية من الموارد المائية المهمة في المناطق الصحراوية والشبه صحراوية في العالم وفي العراق بشكل والمياه الجوفيه هي المياه التي تسربت خالل طبقات األرض من األمطار واألنهار والبحيرات العذبه وبمرور خاص. اق مختلفه عن سطح األرض تتغير من موقع ألخر وذلك السنين هذه المياه تتواجد في باطن األرض على أعم حسب التكوين الجيولوجي للتربه. وأهميه المياه الجوفيه تزداد بصفه مستمره نظرا لزياده الطلب على المياه لجميع األغراض , الزراعيه , الصناعيه والشرب. -تناول البحث محورين لكي تحقق المسح الشامل لمنطقة الدراسة: تم الحصول على بيانات تخص المياه الجوفية من وزارة االعمار واالسكان من خالل فحوصات تحريات : االول التربة التي اجريت لمنطقة الدراسة)محافظة النجف االشرف( تم التعرف من خاللها على اعماق المياه الجوفية وسائل الظهار مناسيب المياه وطبيعة طبقاتها وتم االستعانة ببرنامج نظم المعلومات الجغرافية كاحدى ال -الجوفيةوكانت : ( الى الموقع رقم 1خمس مناطق مختلفة في محافظة النجف االشرف تمثلت في ) المواقع من رقم ) (1 (متر.11-1.3تراوحت اعماق المياه الجوفية فيها) (2114( لعام 5) 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 اعاله تمثلت في)الموقع من ( 1عشر مناطق مختلفة في محافظة النجف االشرف تختلف في مواقعها عن ) (2 (متر.1.9-12.5) تراوحت اعماق المياه الجوفية فيها (2113لعام 11الى الموقع رقم 1 : تم اجراء دراسة فيزيائيةو كيميائية على مناطق مختلفة موزعة على محافظة النجف االشرف وهي تختلف الثاني 81-21رئية النجف الفضائية تراوحت اعماقها من )( وهي موضحة في م2,1عن المناطق في المحور االول ) حيث عمدت وزارة البيئة بااليعاز الى مديرية بيئة محافظة النجف االشرف باجراء فحوصات 2114لعام متر ( وقد تم طرحهافي البحث لغرض معرفة امكانية استثمارهامن خالل فحوصات دورية لهذه االبار للوقوف على نوعها. ( ecالتوصيلية الكهربائية ),( phاالس الهيدروجيني ) ,فحوصات )قياس درجة الحرارة )الماء( الوزارة. تمثلت ب ,k,االيونات الموجبة) tss االمالح العالقة الكلية, tdsاالمالح الذائبة الكلية , turbidityالعكورة , mg2+,ca2+,na+ األيونات السالبة) so4-,cl-, hco3-,-co3, no3-) po4 ,-مقارنة (وتمت ,(w. h . oنتائج هذه الفحوصات مع جداول)صالحية المياه للشرب وفقا لمعيار منظمة الصحة العالمية (( و )محددات المياه isecoصالحية المياه للري وفقا لمعيار المنظمة االسالمية للتربية والثقافة والعلوم )) الصناعية(. ية في محافظة النجف االشرف موجودة باعماق ومناسيب تم التوصل من خالل البحث الى ان المياه الجوف ونوعيات ممكن االستفادة منها كمصدر بديل ولالغراض المختلفة منها الشرب , الري , والصناعات المختلفة خاصة وان هناك بعض االبار تحتوي على نسبة من الملوحة يمكن معالجتها بالطرق الحديثة قبل استخدامها. studying the development potentials to invest groundwater in najaf ashraf state zainab degan abbasse al-kelabbee a.leacture kufa university physical planning college environmental department abstract the under ground water is considered one of the most important resources of water in desert and semi desert regions in the world and spatially in iraq. the underground water is the water that escaped through the surface layers from rain water , rivers , and sweet laks , by time this water exists in the earth care with depth that differs from one place to another due to the geological nature of soil . the importance of underground increases conyounsoully with the requsel for water to an agriculture , undustrial , and drinking needs. the research investigated tow points in order to achieve a comprehensive survey of the study area: the first : the undergroundwater data was taken from ministry of construction and housing through soil invistegations tests that was conducted for the study region which through it the depth of 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 underground identified and also its layers type and characteristces and we used giographical information system program as a tool to show the levels of undergroundwater 1-the study area included five different regions in najaf state they are locations from 1 to no. 5 for year 2014 the depths of ground water on it ranged from (1.3-11)m. 2-ten different regions in najaf state that differ from the areas in (1) above they are locations from 1 to no.10 for year 2013 the depths of ground water on it ranged from (1.9-12.5)m. the second :a physical and chemical study was conducted on different areas spread over the province of najaf that differ from the areas in the first section (1,2) and they are shown in the visible najaf satellite, the depths ranged from (20-90 m) for 2014 were obtained from the environment directorate of najaf, where the ministry instructed the environment directorate to conduct periodic tests for these wells to determine their types. and they were discussed in the research in order to know the possibility of investing them through the ministry experiments. they were represented by the tests (measuring temperature (water), potential hydrogenii (ph), electrical conductivity (ec),turbidity, total dissoluble salts tds , total suspended salts tss, cations (positive ions) (k, mg2 +, ca2 +, na +) negative ions (so4-, cl-, hco3 -, co3, no3-, po4-,), and results of these tests were compared to the tables of (water drink validity) according to the who’s standards (world health organization), (water validity for irrigation, according to the standard of the islamic education, culture and science organization (iseco) and (industrial water criteria)). it was conducted through the research that the groundwater in the province of najaf exists with depths, levels and types, that can be utilized as an alternative resource and for different purposes, including drinking, irrigation, and various industries with some treatments that the water needs in several wells, in order to be valid for the required purposes specially treating it from salts. دراسة االمكانات ،خصائص المياه الجوفية ، تنمية المياه الجوفية ، اعماق المياه الجوفية ، : كلمات مفتاحية محافظة النجف االشرف المقدمة: يحصل اإلنسان على احتياجاته المائية من مصدرين أساسيين وهما مصادر المياه السطحية وتشمل مياه األنهار والبحيرات ومجاري الوديان ومصادر المياه األرضية وتشمل اآلبار والينابيع والكهوف مكون ما يسمى بالمياه الجوفية رسوبية تكونت عبر أزمنة مختلفة تكون حديثة أو قديمة جدا وهي عبارة عن مياه موجودة في مسام الصخور ال لماليين السنين. فقد نشأ اعتقاد بأن المياه السطحية تشكل المورد الرئيسي إلحتياجات العالم من المياه ولكن في األكبر % من المياه العذبة المتاحة على كوكب األرض توجد في األنهار والبحيرات أما الجزء 3الواقع فإن أقل من ( كيلومتر مكعب. كما وتعد دراسة المياه 111,111% فإنه يوجد في باطن األرض وُيقدر بحوالي )87والذي يمثل 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 الجوفية من الدراسات المهمة وذلك من اجل الحصول على مصادر للمياه ممكن أن تستخدم ألغراض التنمية في ولألغراض البشرية. المجال االروائي والزراعي والمجاالت العمرانية والصناعية الى تحليل بعض مياه ]3[لقد اجريت بحوث عديدة في مجال استثمار المياه الجوفية حيث عمد الباحث البحث الى [13]االبار في منطقة الخفاجيةفي االنبار من اجل معرفة مدى مالئمتها الغراض الري والشرب وعمد في دراسة هيدروجيوكيمياوية [5]استخدام المياه الجوفية الغراض الري في منطقة مشروع المسيب , كما وبحث للمياه الجوفيةفي الجزيرة القريبة من سامراء تم من خاللها التوصل الى امكانية استخدام هذه المياه الغراض الري كربالء ان منطقة الدبدبة –للمنطقة المحصورة بين نجف في دراسة هيدروجيولوجية ]6[والنشاط البشري. ووضح على الرغم من وجود االمالح في مياهها الجوفية بنسبة عالية لكنها تستخدم الغراض الزراعة. وعمل الباحثان .على اجراء دراسة فيزيوكيمياوية لمعرفة جودة المياه واجريت الدراسة على آبار مدينة )غانا(الهدف منها [15] دراسة في [14] دة واضعي القرار من اجل وضع معايير خاصة لمنع تلوث المياه . وايضا اجرى الباحثين مساع ( بئر في مدينة تبريز ومناطقها 71مدينة تبريز في ايران حيث تم تقييم المياه الجوفية من خالل اخذ عينات ) الريفيةومن خالل اجراء الفحوصات الكيميائية لهذه المياه. مشكلة البحث تتمثل بالنقاط التالية: ر بالذكر انومن الجدي ما هي طبيعة طبقات المياه الجوفية في محافظة النجف االشرف ؟ -1 ماهي مناسيب واعماق المياه الجوفية في محافظة النجف االشرف ؟ -2 ماهي نوعية المياه الجوفية في محافظة النجف االشرف؟ -3 اما فر ضية البحث فهي الجوفية في محافظة النجف االشرف هي ذات طبقات مختلفة بخصائص مختلفةان المياه -1 ان المياه الجوفية بمحافظة النجف االشرف ذات مناسيب واعماق معينة تختلف حسب طبوغرافية منطقة الدراسة.-2 ان نوعية المياه الجوفية تختلف من مكان الخر وحسب الخصائص الكيمياوية لها.-3 هي كاالتي:وان اهمية البحث ف ان العالم العربي مقبل على شح في الموارد المائية فال بد من اجراء كافة الدراسات ذات العالقة بالبحث عن مصادر بديلة كالمياه الجوفية . 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 ويوضح منهج البحث بالخطوات االتية: محافظة النجف االشرف سوف يعتمد البحث من خالل المنهج االستقرائي الستعراض واقع حال المياه الجوفية في وبعد ذلك مقارنة ما هو منتج مع المواصفات العالمية الخاصة بصالحية المياه الجوفية للشرب والري والصناعة وتشخيص مدى مالئمة المياه الجوفية لهذه االغراض وبالتالي الخاصة بالنتائج والتوصيات الخاصة بالبحث. منطقة الدراسة ( باحيائه الشمالية والجنوبية 2-1فظة النجف االشرف بالنسبة للمحور االول)تمثلت منطقة الدراسة في محا ( 11-1ومن ) 2114(بالنسبة لبيانات 5-1والوسطى وحسب المناطق التي تناولها الباحث في بحثه الموقع ) كل رقمالش( كما في gisوكما تم توضيحه من خالل برنامج نظم المعلومات الجغرافية ) 2113بالنسبة لبيانات الحقا. تمثلت النقاط الموجودة في الشكل المواقع التي تم اخذ فحوصات المياه الجوفية لهاوكما موضحة (0) مواقعها على مرئية النجف الفضائية وتم الحصول على البيانات عن طريق فحوصات تحريات التربة من قبل خاللها معرفة مناسيب وطبيعة المياه الجوفية قبل مختبرات وزارة االعمار واالسكان وهي الفحوصات التي يتم من بالنسبة للمحور الثاني فان االبار المفحوصة اما. اقامة االسس التابعة للمنشآت المراد اقامتها على الموقع المعني وكما وهي تختلف عن المناطق بالمحور االول كيمياويا موزعة على مناطق متفرقة من محافظةالنجف االشرف ( , قرية مظلوم 3,2( , بحر النجف آبار رقم)1تمثلت بمناطق) بنات الحسن بئر رقم) (5الشكل رقم )ي مالحظ ف (, حي 12(, حي ميسان بئر رقم )11( , حي الحرفيين بئر رقم )11, 8,2,7,6(, البراكيةآبار رقم )5,4آبار رقم ) كربالء -( , طريق نجف18نفط بئر رقم )( , حي ال12( , حي الغدير بئر رقم )17,16,15,14,13الحنانةبئر رقم) (. 22,21.21بئر رقم ) العوامل التي تؤثر على المياه الجوفية اوال :السطح 2كم 22221تقع جنوب غرب العراق تصل مساحتها -محافظة النجف احدى محافظات الفرات األوسط 2كم 432317% من مساحة العراق البالغة 6.6وتشكل المنطقة من قسمين :ويتألف سطح % من مسااحة المحافظة5كم ويسااوي 1311القسم الشرقي )السهل الرسوبي /تصل مساحتها الى -1 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 2كم 38111% من مساحة السهل الرسوبي البالغة 1.4وحوالي %من مساحة المحافظة 85وتشكل 2)كم 27524القسم الغربي /الهضبة الغربية /تصل مساحتها ( -1 أن المساحة العظمى تتجسد في منطقة الدراسة متمثلة بالهضبة الغربية .من هذا نجد الخصائص المناخية ثانيا: نستعرض ابرز الخصائص المناخية ، (0رقم ) الجدوليؤثر المناخ تاثير مباشر على احتياج المزروعات للمياه في (ملم , اذ تتباين معدالت سقوط 011.0)في منطقة الدراسة بلغ لكمية االمطاريتضح من الجدول ان المجموع في حين تنقطع كليا في شهر )حزيران ( ملم51.7)االمطار شهريا لتصل في اقصاها في شهر كانون الثاني وتبلغ ايلول( من ذلك تكون االمطار قليلة مما التساعد على تلبية االحتياجات المائية المطلوبة لسد -آب -تموز – ويتباين هذا المعدل (43.5)فان المعدل السنوي العام لها يبلغ للرطوبة النسبيةالنسبة حاجة المزروعات , اما ب وذلك لكثرة الغيوم وسقوط االمطار خالل هذا الشهر (%71)شهريا ليصل الى اقصاه في شهر كانون الثاني ويبلغ فاع درجة الحرارة خالل وذلك الرت (%57)ثم تاخذ هذه المعدالت باالنخفاض لتصل ادناها في شهر تموز لتصل هذا الشهر مما يؤدي الى فقدان رطوبة التربة وزيادة الجفاف وبالتالي زيادة نسبة الضائعات من السطوح المائية , اذ تنشط حركة الرياح في فصل (م/ثا5.5)فان المعدل السنوي العام لسرعة الرياح يبلغ للرياح والتربة , بالنسبة م/ثا على التوالي (3.0-3)سرع الرياح في االشهر الحارة )حزيران, تموز( بمعدالت الصيف لتسجل اعلى معدالت ل في حين تقل سرعة الرياح عن هذه المعدالت في االشهر الباردة لتصل ادناها في شهر )تشرين الثاني وكانون مائية والتربة على التوالي حيث ان الرياح تؤدي الى زيادة نسبة التبخر من السطوح ال(0.2-0.2)االول الى يتضح من الجدول ان مجموع كمية التبخر السنوي مرتفعة وتبلغ التبخروبالتالي زيادة حجم الضائعات المائية , ويعزى ذلك الى ارتفاع ( ملم278.2)وتتباين معدالت التبخر لتبلغ اقصاها في شهر تموز (ملم3243.2) لة او انعدام الغيوم في حين تبلغ ادناها في شهر كانون الثاني درجات الحرارة وانخفاض الرطوبة النسبية في الجو وق ويعزى ذلك الى انخفاض درجات الحرارة وارتفاع معدالت الرطوبة النسبية في الجو وزيادة (ملم 75.7)بمعدل الريات الغيوم ومما يجدر الذكر ان ارتفاع نسبة التبخر تؤدي الى زيادة حجم الضائعات المائية وبالتالي زيادة عدد يمثل االشعاع الشمسي المصدر الرئيسي للطاقة على سطح االشعاع الشمسي, التي تحتاجها المزروعات , وانه العامل المهم في تحديد مقدار الحرارة المتوفرة في المنطقة والتي يتم من خاللها تحديد معدالت , االرض الموقع الفلكي في كمية االشعاع الشمسي وزاوية يؤثر درجات الحرارة التي تحدد قيم الضغط الجوي في المنطقة ويتضح من الجدول ان المعدل السنوي العام لكمية االشعاع الشمسي بلغ سقوط االشعاع الشمسي بسبب 5( سعرة/سم770.8)وهذا المعدل يتباين شهريا اذ يبلغ اقصاه في شهر حزيران 5(سعرة/سم254.28) تأخذ كمية االشعاع بر زاوية االشعاع الشمسي وطول مدة السطوع الشمسيصفاء السماء وقلة الرطوبةالنسبية وك 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 الشمسيبالتناقص تماشيا مع تناقص زاوية االشعاع وطول النهار اذ تصل في ادناه في شهر كانون االول اذ تبلغ ذلك وذلك الن زاوية االشعاع الشمسي تصل الى اقل ما يمكن و 5( سعلرة/سم522.14)كمية االشعاع الشمسي لكثرة الغيوم وارتفاع معدالت الرطوبة النسبية وسقوط االشعة الشمسية بصورة مائلة يتضح من ذلك ان منطقة الدراسة تستلم كمية كبيرة من االشعاع الشمسي لساعات طويلة من النهار بسبب موقعها الفلكي وهذا يؤثر في عات المائية من سطوح االنهار والجداول وترب الحقول ارتفاع درجات الحرارة ونسب التبخر والنتح وزيادة حجم الضائ , الزراعية االمر الذي يتطلب معه زيادة كميات مياه الري وبالتالي استنزاف الموارد المائية في منطقة الدراسة يتباين هذا المعدل شهريا اذ º(م54.0يبلغ ) يتضح من الجدول ان المعدل السنوي لدرجات الحرارةدرجات الحرارة , ثم تأخذ باالنخفاض º( م32.7)حتى يصل اقصاه في شهر تموز º( م07.8)بدأ باالرتفاع مع شهر آذار بمعدل يتضح من الجدول ان ارتفاع درجات الحرارة وخاصة خالل اشهر º( م01.2)ليصل في ادناه في شهر كانون الثاني تبخلر من السطوح المائية من جهة وارتفاع النتح من سطوح االوراق النباتية الصيف الحار يؤدي الى ارتفاع نسبة ال من جهة اخلرى االمر الذي يؤدي الى زيادة حجم الضائعات المائية واستنزاف الموارد الموارد المائية السطحية -ثالثا:الخصائص الطبيعية للمياه الجوفية: اصل المياه الجوفية -0 ة في منطقة الدراسة من مياه جوفية ذات اصل بحري متمثلة بخزان الفرات الى مياه جوفية يتباين اصل المياه الجوفي ذات اصل جوي متمثلة بخزان الدمام وهي اهم خزانات منطقة الدراسة كون التكوينات الجيولوجية التي تحوي هذه الخزانات تنتشر ضمن مساحات واسعة في هذا االقليم من منطقة الدراسة. wt)الماء الجوفي )عمق او منسوب , مستوى سطح -5 ( و هو يعرف بمستوى سطح الماء االستاتيكي water tableهو عمق سطح الماء الجوفي أسفل سطح األرض ) ) أي الساكن ( الذي يكون في األحوال العاديه بدون ضخ مياه و هو يكون سطح الماء الجوفي واحد في كل من خدم أال لخزان المياه الجوفي حر السطح . تتباين اعماق المياه الجوفية في البئر و الخزان وهذا المصطلح ال يست منطقة الدراسة مع ارتفاع السطح في منطقة الدراسة من مكان آلخر اذ تكون ذات عمق كبير في المناطق االكثر م وذلك لزيادة 211 م الى51ارتفاعا وبشكل عام يزداد عمق هذه المياه كلما اتجهنا نحو الغرب والشمال الغربي من المناطق التي تم التعرف على اعماق ( 5الشكل رقم ) ( يوضح 1,2االرتفاع بهذا االتجاه. فبالنسبة للمحور االول ) المياه الجوفية فيها من خالل فحوصات تحريات التربة للمشاريع المقامة في تلك المنطقة وهي موزعةبمواقع حسب ( وباللون 11-1ومن ) 2114( وباللون االحمر للبيانات الخاصة لعام 5-1تواجدها على المرئية تمثلت من ) يوضح (5للجدول رقم )كما وتم ذكر اسماء المناطق لهذه المواقع ايضا. بالنسبة 2113االزرق للبيانات لعام -11m)ومن ) 2113لبيانات m 1.9-12.5) اعماق ومناسيب هذه المناطق حيث تراوحت االعماق من ) 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 12 1.3m ويحتوي البحث من خالل المرئية على فحوصات في منطقة الحيدرية , منطقة العباسية 2114لبيانات . بالنسبة , طريق نجف كربالء وفي البراكيةوهي تقريبا خارج الحدود البلدية للمناطق السكنيةلمنطقة الدراسية . ]2 [( متر81-21للمحور الثاني فقد تراوحت االعماق للمياه الجوفية ) 1] 5 [حركة المياه الجوفية في منطقة الدراسة ثالثا: تقسم حركة المياه الجوفية الى ثالث مناطق رئيسية وهي مناطق السهل الفيضي ومنطقة جزيرة النجف والبادية .  تكون حركة المياه الجوفية عمودية على اتجاه االنهار ذهابا وايابا حسب مناطق السهل الفيضي : مناسيب مياه االنهار ارتفاع وانخفاض  تكون حركة المياه الجوفية باالتجاه الشرقي واالتجاه الجنوبي الشرقي الشمالية منطقة جزيرة النجف : حيث المنطقة االكثر انخفاضا في الهضبة  تكون حركة المياه الجوفية باالتجاه الشمالي الشرقي حيث المنطقة االكثر انخفاضا مناطق البادية : وهي مناطق بحر النجف 1] 5 [رابعا: توزيع وكثافة االبار في منطقة الدراسة -تتمركز االبار في المناطق التالية: ( بئر منتج تتمركز في المناطق القريبة من 1211جزيرة النجف الشمالية وتتراوح اعداداالبار فيها تقريبا ) -1 كربالء –طريق نجف البادية تكثر االبار في بحر النجف في جميع مناطقه حيث النوعية الجيدة والكمية العالية للمياه الجوفية -2 الى مرور فالق ابو الجير الذي يشكل خزان جوفي حيث تعتبر المنطقة مناطق تكسرات وخزن اضافة عمالق مع وجود تكوينيين عمالقيين هما تكوين الفرات وتكوين الدمام . ومناطق بحر النجف هي مشجعة ( بئر كذلك مناطق الحياضة والرحبة وغيرها اما 511على االستثمار ويبلغ عدد االبار التقريبي الى حدود ) ف وصوال الى الحدود العراقية السعودية فهي تعتبر مناطق اعادة تغذية مناطق جنوب غرب بحر النج ومناطق ال تتجمع فيها المياه الجوفية لذا تقل فيها االبار وتكون االبار ذات انتاجية قليلة مع اعماق كبيرة ووجود نوعية رديئة للمياه حيث يحتوي على امالح عالية ومواد كبريتيةالجداول. اويةالفحوصات الكيمي ( 22من اجل معرفة االمكانات المتاحة الستثمار المياه الجوفية في محافظة النجف االشرف تم الحصول على ) نموذج من االبار مفحوصة كيمياويا من قبل دائرة بيئة محافظة النجف االشرف لبيانات غير منشورة ولعام 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 الجدول رقم ) وتم ترقيمها في (5رقم ) الشكلفي حصرا وكما موضح مواقعها على مرئية النجف الفضائية 2114 حسب وجودها في المرئية . وكما مالحظ من المرئية فان االبار موزعة على مناطق متفرقة من محافظةالنجف ( 3 ( , قرب بحر النجف آبار 1االشرف وهي تختلف عن مناطق المحور االول تمثلت بمناطق) بنات الحسن بئر رقم) (, حي 11( , حي الحرفيين بئر رقم )11, 8,2,7,6(, البراكيةآبار رقم )5,4لوم آبار رقم )( , قرية مظ3,2رقم) ( , حي النفط بئر رقم 12( , حي الغدير بئر رقم )17,16,15,14,13(, حي الحنانةبئر رقم)12ميسان بئر رقم ) متر (81-21(وتراوحت اعماق هذه االبار من )22,21.21كربالء بئر رقم )-( , طريق نجف18) ]4 [القياسات الفيزيائية والتحاليل الكيميائية اوال :القياسات الفيزيائية (ph)تشــــمل التحاليــــل الفيزيائيــــة علــــى قيــــاس درجــــة الحــــرارة )المــــاء( واللــــون والطعــــم والرائحــــة واالس الهيــــدروجيني وتــم tssواالمــالح العالقــة الكليــة tdsواالمــالح الذائبــة الكليــة turbidityوالعكــورة (ec)والتوصــيلية الكهربائيــة قياس بعض هذه الفحوصات في دائرة بيئة محافظة النجف لمجموعة من االبار الموزعة على منطقة الدراسة. ثانيا :التحاليل الكيميائية اض وتلقــي تعتبــر الدراســات الكيمياويــة للميــاه الجوفيــة مهمــة فــي تحديــد صــالحية الميــاه لألســتعماالت المتعــددة االغــر الضـوء علـى تـأريخ الصـخور الخازنــة وسـرعة وحركـة الميـاه، وان عمليـة دراســة التحاليـل الكيميائيـة تفيـدنا فـي التحــري عـــن التجمعـــات المعدنيـــة وتعتبـــر مهمـــةوذلك كونهـــا تســـتطيع تحديـــد صـــالحية الميـــاه لألســـتخدامات المتنوعـــة كميـــاه يائية للمياه على المكونات الغيـر عضـوية والتـي شـملت علـى العناصـر الشرب والزراعية ، لقد تم اجراء التحاليل الكيم الرئيسية ، العناصر الثانوية ، العناصر الثقيلة. major componentsالمكونات الرئيسية ان تعيــين تراكيــز العناصــر االساســية للميــاه يــرتبط ارتباطـــا وثيقــا بصــخارية التكــوين ويــتم تعيــين تراكيزهــا بأســـتعمال ,+mg2قياسـية واجهـزة معينــة , ان االيونـات الرئيسـية الشـائعة والمتحكمــة فـي التكـوين الكيميــائي للميـاه هـي طرائـق ca2+, na+, k+ كأيونات موجبة اما بالنسـبة لأليونـات السـالبة فهـيso4-,cl-, hco3-,co3 وقـد اجريـت هـذه التحاليل في مختبرات بيئة محافظة النجف االشرف. miner componentsالمكونات الثانوية وتشمل : -nitrate no3ايون النترات -1 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 phosphate po4-3ايون الفوسفات -2 heavy componentsالمكونات الثقيلة وتمتاز بعض هذه العناصر بأنها epmاو الـ ppmتوجد العناصر الثقيلة في الطبيعة بكميات قليلة وتقاس بوحدة غذاء ٍاساسي لبعض االحياء وعند زيادة تراكيزها عن الحد المسموح بها تصبح سامة ان هذه المجموعة تشمل ولم . cuوالـ coوالـ feوالـ niوالـ znوالـ cr والـ pbوالـ cdعناصر كثيرة بضمنها العناصر المذكورة الـ الفحوصات لعدم وجود فحوصات خاصة بها في الدائرة المعنية.يتسنى لنا الحصول على هذه ثالثا :التحاليل البكتريولوجية البكتريا هي مجموعة مـن الكائنـات الحيـة الدقيقـة احاديـة الخليـة او خيطيـة ، شـعرية الخليـة ذات اشـكال اسـطوانية او يــوان والنبــات ولهـذا تــم االهتمــام بدراســة دائريـة، وان بعضــها تســبب امـراض وعلــل خطــرة وفتاكــة تصـيب االنســان والح بكتريولوجية المياه وخصوصا في نهاية القرن العشرين لمدى خطورة ووجود هذه االنواع من البكتريا الفحوصات الفيزيائيةوالكيمياوية للمياه الجوفية في منطقةالدراسة ان المياه الجوفيه تعتبر أكثر صالحيه من المياه السطحيه من الناحيه الصحيه ولذا يفضل االعتماد عليها كمصدر لمياه شرب صالحه طالما تواجدت بكميه كافيه وكانت ال تحتوي علي شوائب تحد من استعمالها وهذا تبين الدرجه (2, 2, 4والجداول ) االمر يعد من اهم االشتراطات الصحيه الواجب توافرها في مياه اآلبار القصوى التي تتواجد بها الشوائب المختلفه في المياه كما تبين الحد األقصى المسموح بتواجده في المياه الصالحه لالستعمال والحد المفضل عدم تجاوزه لتركيز هذه الشوائب فاذا زادت الشوائب في المياه الجوفيه عما هو مذكور في يتم معالجتها قبل االستعمال حتى يقل تركيزها إلي الحد األقصى المفضل الموجود في نفس الجداول هذه الجدول -يتضح ما ياتي: (3الجدول رقم )من ( لديها عند mg/l 837( واوطأ قيمة )7( عند البئر رقم )mg/l 5813بلغت اعلى قيمة بمقدار ) (t.d.s)قيمة (4الجدول رقم ) ( للشرب whoحدود غير المقبول بها وفقا لمعيار )( وهذه القيم تقع ضمن ال8البئر رقم ) كما ويالحظ تباينا مكانيا من بئر آلخر حيث سجلت اعلى تراكيز لها عند (2الجدول رقم ) للري isecoومعيار ( ان 3) ( واوطا قيم لها عند االبار االخرى كما اظهر الجدول رقم 22, 21, 14, 2, 7, 6, 5, 4االبار ) (وهي في جميع االبار 6( عند البئر )11,171( للمياه الجوفية لمنطقة الدراسة بلغت اعلى قيمة لها )ecقيم ) للري مع وجود تباينا iseco( للشرب ومعيار whoاالخرى تقع ضمن الحدود غير المقبول بها وفقا لمعيار ) ( وهو مطابق للمواصفتين انفة للذكر للشرب 1.464تها )حيث بلغت قيم 8مكانيا من بئر آلخر باستثناء البئر رقم ( 12( عند البئر )2.5( الى )13( عند البئر )6.3فقد تراوحت اقيامه بين ) (ph)والري . اما بالنسبة لقيم 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 ( وهي حالة شاذة وتعتبر هذه القيم ضمن الحدود المقبول بها وفقا لمعيار 14( عند البئر )17.1باستثناء القيمة ) who ( لمياه الشرب ومعيارiseco ( للري ومعيار محددات المياه الصناعية انظر الجدول رقم )مع 6 ) ( عند 262.4( فقد بلغت اعلى قيمة له )mgوجود تباينا مكانيا من بئر آلخر , بالنسبة لقيمة عنصرالمغنسيوم ) ه يقع خارج نطاق الحدود المسموح بها ( وهو في اغلب قيم7( عند البئر رقم )27.5( واوطأ قيمة )6البئر رقم ) فقد تجاوزت اغلب cl)وخارج معيار الصناعة . بالنسبة ) isecoللشرب وكذلك معيار who وفق معيار ( وهو خارج الحدود المسموح so4اقيامه الحدود المسموح بها للشرب والري والصناعة بالنسبة المالح الكبريتات ) turb)خارج الحدود المسموح بها للشرب والري والصناعة , العكورة) ca)) به للشرب والري والصناعة , اما ( فانها no3( خارج الحدود ,بالنسبة للنترات)14فجميع القيم تقع ضمن الحدود المسموح بها للشرب ما عدا البئر ) فانه يقع (doفي بعض االبار تقع ضمن الحدود المسموح بها للري وبعض الصناعات , ولالوكسجين المذاب ) ( , بالنسبة للمواد او الرواسب العالقة 21, 17, 11, 4ضمن الحدود المسموح بها للشرب ما عدا االبار ) (t.s.s( فقد تم فحصها فقط للبئر رقم )وهي خارج الحدود المسموح بها للشرب , وضمن الحدود المسموح 15 ) (, وضمن 11المسموح بها للشرب ما عدا البئر رقم )( وهو يقع خارج الحدود naبها لبعض انواع الصناعات, ) (, بالنسبة 21, 12, 16, 13, 11, 11, 6الحدود المسموح بها لبعض انواع الصناعات بانسبة لآلبار رقم ) ( , وضمن الحدود المسموح 21( فهو يقع خارج الحدود المسموح بها للري ما عدا البئر رقم )kلعنصر البوتاسيوم ) ( فهي temp( , بالنسبة لدرجة حرارة المياه )2ض الصناعات لجميع االبار المفحوصة ما عدا البئر رقم )بها لبع (فالتوجد مواصفات o&g( والمواد العضوية )po4تقع خارج الحدود المسموح بها بالنسبة للري ,بالنسبة للفوسفت ) ستثمار وتنمية المياه الجوفية في محافظة تذكر لغرض المقارنة. ومن خالل ما تقدم نالحظ ان هناك امكانية أل ( حيث ان المياه الجوفية في منطقة الدراسة موجودة 2النجف االشرف وذلك من خالل مالحظتنا للجدول رقم ) باعماق قريبة ومناسبة من سطح االرض الطبيعي بحيث ممكن استثمارها واالستفادة منها لالغراض المختلفة , اما المياه الجوفية فقد تم مناقشتها من خالل االبار المفحوصة والموضحة نتائجها في الجدول رقم بالنسبة لنوعية (حيث وجد انها يمكن استخدامها لري بعض المحاصيل الزراعية التي تتحمل الملوحة, اضافة الى امكانية 3) لترة مياه االبار والتخلص من استثمارها بطريقة علمية في الري وذلك باستخدام تقنيات الري الحديثة من خالل ف الملوحة واستخدامها لري المحاصيل الزراعية المختلفة , اضافة الى امكاننية استخدامها للصناعات المختلفة وخصوصا اذا عولجت بطريقة صحية وعلمية كما يمكن استخدامها لالغراض المنزلية بعد تصفيتها واستخدامها مرة دامها للشرب بعد معالجتها بالطرق العلمية الحديثة. تمتاز مياه آبار منطقة الدراسة اخرى كما ان هناك امكانية استخ بارتفاع نسبة الملوحة وهي ايضا تختلف من منطقة الى اخرى ولكن ليس بالملوحة العالية جدا اذا ما قورنت بملوحة ن اجل االستفادة منها اذا ما علمنا اننا البحار , وهي ممكن معالجتها واستثمارها وتنميتها بالطرائق العلمية الحديثة م مقبلون على ازمة مائية كبيرة بسبب انخفاض مناسيب نهر الفرات بسبب السدود التركية والسورية. لذلك البد من 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 النظر الى مورد مائي اخر وهو المياه الجوفية والموجود بكميات ال باس بها في منطقة الدراسة مما ستوجب الجهات تمام بهذا المورد المائي المتاح االستفادة منه في االستخدامات المختلفة للمحافظة على المياه السطحية المعنية االه من النضوب. االستنتاجات ان للعناصر المناخية تأثير مباشر على بعض االحتياجات المائية وخاصة ري المزروعات وخاصة من -1 والرياح مما يشير الى وجود ضرورة ملحة للبحث عن ناحية توفر االمطار وعدمها ودرجة الحرارة والرطوبة مصدر بديل للمياه السطحية متمثال بالمياه الجوفية . ان اعماق المياه الجوفية تتغير تبعا لطبوغرافية منطقة الدراسة وكذلك تعتمد هذه االعماق على عوامل -2 طبيعية وبشرية تم التطرق اليها مسبقا. لدراسة موجودة بمناسيب واعماق مناسبة وقريبة عن سطح االرض ان المياه الجوفية في منطقة ا -3 ويختلف هذا المنسوب عمقًا من مكان إلى آخر, فيكون قريبًا من سطح األرض في الطبيعي)المحور االول( المناطق الرطبة الغزيرة األمطار, والقريبة من البحار واألنهار بحيث يمكن االستفادة منها لالغراض المتمثلة في المناطق في مواقع اخرى عض المواقع وذات عمق اكبر وبعيدًا عن سطح األرضالمختلفة في ب )المحور الثاني(. الجافة كما في سهولة وانسيابية رسم خصائص ومواقع المياه الجوفية من حيث رسم وتوزيع المواقع المفحوصة للمياه -4 الجغرافية. الجوفية على منطقة الدراسة باستخدام تقنية نظم المعلومات اثبتت الفحوصات الكيمياوية التي تم اجراؤها على منطقة الدراسة للمياه الجوفية بامكانية استثمار المياه -5 الجوفية واستخدامها لالغراض المختلفة كمصدر بديل عن المياه السطحية التوصيات مصدر مساعد من اجل تجاوز ان تهتم الجهات المعنية والسلطات المختصة بالمياه الجوفية واعتبارها -1 االزمة المائية المحتملة وخاصة بعد اقامة السدود التركية على االنهار العراقية . العمل على تفعيل ادارة المياه الجوفية وذلك من خالل مراقبة االستخدام الجائر لبعض انواعها وان يكون -2 ؤمن مستقبل االجيال القادمة .خاضع للرقابة الفعلية لغرض استدامتها واالستفادة منها بشكل ي تفعيل وسيلة الري بالتقنيات الحديثة لعدام استنزاف الموارد المائية بالري السيحي. -3 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 اجراء بعض عمليات المعالجة والفلترة والتصفية لبعض نوعيات المياه الجوفية لتكون صالحة لجميع -4 االستخدامات المطلوبة بضمنها الشرب والري والصناعات المختلفة. المصادر تقارير وزارة االعمار واالسكان المختبرات االنشائية, فحوصات تحريات التربة , بيانات غير منشورة , -1 2114-2113للعامين ، دراسة الصفات الفيزياوية والكيمياوية واحتمالية تلوث المياه 2111الجنابي، ، محمود عبدالحسن ، -2 جامعة بغداد. –كلية العلوم –رسالة ماجستير غير منشورة محافظة كربالء. –الجوفية في منطقة شثاثة الحياني , عبد الستار جبير, تقييم المياه الجوفية لبعض آبار قرية الخفاجية في محافظة األنبار , كلية -3 .2118جامعة الموصل, -علوم البيئة وتقاناتها محافظة االنبار, اطروحة –ة الرحالية السعدي , محمود عبد االمير , التقييم البيئي للمياه الجوفية منطق -4 2114ماجستير غير منشورة , كلية العلوم , جامعة بغداد , العراق , –عباس ,فالح حسن, دراسة هيدروجيوكيميائية للمياه الجوفية في الجزيرة القريبة من سامراء -5 .2111قسم علوم الحياة, كلية العلوم, جامعة األنبار , كربالء, قسم الدراسات –راسة هيدروجيولوجية للمنطقة المحصورة بين طريق نجف العزاوي, بتول دمحم, د -6 العراق . -والتحريات ، الهيئة العامة للمياه الجوفية ، وزارة الموارد المائية . بغداد ، االستكشاف الجيوكيميائي لتجمعات المواد المشعة في منطقة 1828المرسومي ، عبدالمطلب حسون ، -7 جامعة بغداد. -كلية العلوم –، غرب العراق، اطروحة دكتوراه غير منشورة شثاثة –هيت 2114المهندس صفاء دمحم , مديرية بيئة محافظة النجف االشرف , وزارة البيئة العراقية, -8 2114مديرية دائرة بيئة محافظة النجف االشرف , وزارة البيئة بيانات غير منشورة , -9 الجمهورية -وزارة االعالم -المائية في العراق وصيانتها من التلوثالموارد -دمحم مهدي الصحاف -11 1876-العراقية 2114فرع النجف , وزارة الموارد المائية العراقية , بيانات غير منشورة , -الهيئة العامة للمياه الجوفية -11 مدى صالحيتها ألغراض الهيل , سعاددمحم, التقييم النوعي للمياه الجوفية في منطقة مشروع المسيب و -12 .2112الري, 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 وزارة النقل والمواصالت , الهيأة العامة لالنواء الجوية والرصد الزلزالي في العراق , قسم المناخ , بيانات غير -13 2114منشورة , 14-m. jeihouni, , a. toomanian, m. shahabi, s. k. alavipanah, 2014 groundwater quality assesment for drinking purposes using gis modelling case study : city of tabriz ,iran. 15-stephen t. odonkor and kennedy k. addo,2013, bacteriological profile and physico-chemical quality of ground water: a case study of bore hole water sources in a rural ghanaian community,int.j.curr.microbiol.app.sci 2(8): 21-40 16-w.h.o., world healthy organization international standard for drinking water geneva switzerland 3 rd edition 1977 p 36 17water resources mongement isiamis educationalg s cientific and cultural organization rabat morocco 1997 p 64 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 14] [(1821-2114المعدالت عناصر المناخ في محافظة النجف االشرف للمدة) :(0جدول رقم ) ]0[في محافظة النجف االشرف 2114-2113مناسيب المياه الجوفية وللعامين :(5جدول ) كمية االشعاع االشهر الشمسي 5سعرة/سم معدل درجات الحرارة الشهري الرطوبة النسبية % سرعة الرياح م/ثا التبخر االمطار/ملم 75.7 20.7 1.7 71 01.2 581.74 كانون الثاني 055.8 15.1 5.5 60.3 13.4 320.37 شباط 510.3 03.2 2.8 51.4 17.9 420.18 آذار 522.7 01.5 2.5 43.7 23.9 228.28 نيسان 418 4.0 2.4 33.4 29.9 273.28 آيار 230.4 0 3 27.8 33.7 770.84 حزيران 278.2 0 3.1 27 35.7 721.18 تموز 232.3 0 2.5 29 35.4 715.23 آب 413.0 0 1.8 33.2 32 217.3 ايلول 522.5 4.2 1.6 43.3 26.4 448.40 0تشرين 044.0 14.8 1.5 29.2 18.2 358.50 5تشرين 27.2 17.5 1.6 70.1 12.65 522.14 0كانون مجموع سنوي 5.5 43.5 54.0 254.28 المعدل السنوي 011.0 مجموع سنوي 3243.2 المنسوب للمياه الجوفية ) اسم الموقع m 5103( لعام ( لعام mالمنسوب للمياه الجوفية) اسم الموقع 5104 (0الموقع رقم ) 4 (0الموقع رقم ) 4.4 (5الموقع رقم ) 2 (5الموقع رقم ) 1.22 (3الموقع رقم ) 3 (3الموقع رقم ) 0.3 (4الموقع رقم ) 0.8 (4الموقع رقم ) 00 (2الموقع رقم ) 05.2 (2الموقع رقم ) 5 (2الموقع رقم ) (7الموقع رقم ) 3.2 (2الموقع رقم ) 3 (8الموقع رقم ) 4.7 (01الموقع رقم ) 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 ]8[الخصائص الكيميائية آلبار منطقة الدراسة :(3جدول ) t . s . s o& g po4 do temp turb k na no3 so4 cl ca th as caco3 mg alk.as caco3 t.d. s e.c ph pa 2.4 1.1 3 2.2 52.8 0 19.8 196. 9 0.9 1,118. 7 410 348 0511 80.5 94 2.24 9 3.572 7.5 0 5.7 0.0 9 6.9 25 7 31.4 253. 7 4.03 690.14 580 541 720 29.2 160 1.97 6 3.043 6.8 5 13. 4 1.1 3 4 25 01. 5 33.8 273. 8 1.15 761.5 680 541 811 73.2 172 2.37 0 3.644 7.7 3 12. 4 0.0 9 3.4 2 21.4 3.0 6 89 362 73.2 1,409. 2 1,00 0 448 1,990 212. 2 4,86 7 7,489 6.7 6 4 0.1 2 7.2 20.4 5.3 46.8 347 7.13 1,352 1,15 0 416 1,950 222 4,59 3 7,065 7.0 9 2 nd 4.1 21.1 9.1 4.5 90 27.2 2,004 2,15 0 1,04 0 3,700 268. 4 81 5,65 0 11.17 0 7.5 2 11. 3 1.1 3 7.7 25.3 1.5 83.7 620. 2 124. 7 2,666. 3 1,40 0 660 2,200 27.5 5,91 3 9,111 7.3 7 1.1 3 2.2 50.2 1.8 261. 5 1,04 0 3.45 2,128. 4 223. 5 1,08 0 2,680 239. 1 4.06 0 8.090 8.1 2 1.5 3 4.3 25 8.5 12 102. 1 5.44 256.9 135 162. 4 590 44.8 937 1,464 7.8 8 4.6 0.1 5 7.6 52 5 39.4 20.1 4 23.3 642.5 280 240 820 27.5 1,64 6 2,529 7.8 01 3.6 3.1 27 0.9 50 118 21.7 1,333. 1 310 656 1,87 56.1 2 312 2,97 3 4,574 7.3 00 9.3 0.0 6 9.4 5 22 2.9 63.7 1,523. 6 540 656 2,500 209 3,26 3 5,020 7.4 05 2.8 0.0 6 5.4 22.6 7.5 08 072 3.27 1666.4 7 350 504 1,770 124. 4 2,78 2 4,282 6.3 03 0.0 9 8.1 9 17.5 33. 5 37.4 351. 8 44.3 1,261. 5 370 600 1,840 82.9 6 4,15 2 6,920 17. 1 04 3 2 0 0.0 3 5.2 55 45.5 298. 5 56.7 2,261. 5 222 2,71 6 4,160 7.5 02 0.0 3 5.3 52 6.4 27 228 58.3 8 1,047. 4 221 241 2,080 117. 12 3,59 7 5,531 6.9 02 0.0 6 3.2 1 18.9 24.2 423. 2 20.7 1,430. 4 450 600 1,800 73.2 521 3,32 7 5,547 6.7 07 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 ] w. h . o) .)] 07صالحية المياه للشرب وفقا لمعيار منظمة الصحة العالمية :(4جدول ) 1.2 4.8 50 24.6 216. 5 1,118. 6 342 5,064 8.5 02 0.0 6 6.5 6 20 5.0 6 38 238. 4 61.8 1,475. 8 580 584 2,000 124. 4 3,70 4 6,072 7.6 3 08 5.2 1.1 5.7 0 52.5 0.7 7 35 045 8.3 1,728. 4 552 251 1,800 122 2,81 3 4,021 6.5 8 51 4.0 1.1 2 2.7 53.2 1.2 02 1,547. 5 1,68 5 275 2,940 185. 4 4,82 0 7,400 6.9 50 1.1 2 2.1 3 02.8 23 221. 2 17.0 9 1,192. 3 1,35 0 211 2,700 170. 8 511 4,83 7 7,443 6.5 55 (ملموز/سم.5.52-1.72(بين )ecتتراوح الملوحة) 0 ملغم /لتر 721-521يجب ان ال تزيد نسبة الرواسب العالقة عن 5 عن حرارة الماء في آخر شهور السنة. ºم 3المياه صيفا باكثر من ان ال تزيد درجةحرارة 3 وحدات ( والطعم والرائحة. 2انعدام اللون )اليزيد عن 4 .2.2-2.2بين phيجب ان يتراوح ال 2 ملغم/لتر خالل جميع الفصول. 4ان ال تنخفض نسبة االوكسجين المذاب في الماء عن 2 سام والمواد الطافية )كاالصباغ والزيوت(يجب ان تخلو المياه من االج 7 (ملغم/لتر.52-2يجب ان التزيد عكورة المياه عن ) 2 (ملغم/لتر.511-72يجب ان تتراوح نسبة الكالسيوم بين ) 8 (ملغم/لتر.021-21يجب ان تتراوح نسبة المغنسيوم بين ) 01 ( ملغم/لتر.411-511يجب ان تتراوح نسبة الكبريتات بين ) 00 ملغم/لتر.221-511يجب ان تتراوح نسبة الكلور بين 05 03 t.d.s (ملغم/لتر.5111-)صفر 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 12 ] [18(isecoصالحية المياه للري وفقا لمعيار المنظمة االسالمية للتربية والثقافة والعلوم ) :(2جدول رقم ) 1]1 [محددات المياه الصناعية :(2جدول رقم ) الحد االدنى الوحدة الرمز المقياس المسموح به الحد االعلى المسموح به 5 1 ملموز/سم ec الموصلة الكهربائية 5111 1 ملغم/لتر t.d.s االمالح الكلية الذائبة 51 1 ملغم/لتر ca الكالسيوم 21 1 ملغم/لتر mg المغنسيوم 41 1 ملغم/لتر na الصوديوم 01 1 ملغم/لتر hco3 البكاربونات 31 1 ملغم/لتر cl الكلور 511 1 ملغم/لتر so4 الكبريتات 01 1 ملغم/لتر no3 النترات 5 1 ملغم/لتر k البوتاسيوم bh 2 2.2 الحموضة النسب المسموح بها المادة الصناعة كاربونات الكالسيوم حديد منغنيز ph المواد الذائبة ملغم/لتر.341التزيد عن ملغم/لتر0.2 ملغم/لتر2 2.2واليزيد على 2.8اليقل عن ملغم/لتر051 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 المواد العالقة صناعة السمنت الكبريتات الكلوريد ملغم/لتر 511 ملغم/لتر 532 ملغم/لتر 011 الصناعات الغذائية والتعليب كاربونات الكالسيوم ph الكالسيوم الكلوريد الكبريتات الحديد المغنسيوم السليكات النترات المواد الذائبة المواد العالقة ملغم/لتر 311التزيد عن 2.2التزيد عن ملغم/لتر051التزيد عن ملغم/لتر 311التزيد عن ملغم/لتر 521التزيد عن ملغم/لتر 051التزيد عن ملغم/لتر 1.5التزيد عن ملغم/لتر 21التزيد عن ملغم/لتر 42التزيد عن ملغم/لتر 221التزيد عن ملغم/لتر 051 التزيد عن الصناعة الورقية الرواسب العالقة الحديد الكلوريدات المواد العالقة الصلبة المواد الذائبة ملغم/لتر 211التزيد عن ملغم/لتر 1.5 التزيد عن ملغم/لتر 1111 التزيد عن ملغم/لتر 475 التزيد عن ملغم/لتر 0121التزيد عن 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 كاربونات الكالسيوم ph ملغم/لتر 1121 التزيد عن 8.4-4.6 يتفاوت بين قطع االخشاب الرواسب العالقة ph ملغم/للقطر 3التزيد عن 8-2يتفاوت بين صناعة النسيج الحديد المنغنيز النحاس االحمر المواد الذائبة الرواسب العالقة كاربونات الكالسيوم ph ملغم/لتر 1.3التزيد عن ملغم/لتر 0التزيد عن ملغم/لتر 1.2عن التزيد ملغم/لتر 021التزيد عن ملغم/لتر 0111التزيد عن ملغم/لتر 051التزيد عن 2وال يزيد عن 2اليقل عن الصناعات الكيمياوية وشبه الكيمياوية الحديد المنغنيز الكالسيوم المغنسيوم البكاربونات الكبريتات المواد الذائبة الكلوريدات ملغم/لتر 2التزيد عن ملغم/لتر 5التزيد عن ملغم/لتر 211التزيد عن ملغم/لتر 211التزيد عن ملغم/لتر 611التزيد عن ملغم/لتر 251التزيد عن ملغم/لتر 5211التزيد عن ملغم/لتر 511التزيد عن 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 الرواسب العالقة كاربونات الكالسيوم القواعد ph ملغم/لتر 11111التزيد عن ملغم/لتر 0111التزيد عن ملغم/لتر 211التزيد عن 8وال يزيد عن2.2اليقل عن الصناعة النفطية السليكات الحديد الكالسيوم المغنسيوم الصوديوموالبوتاسيوم البيكاربونات الكبريتات الكلوريدات النترات الفلوريد المواد الذائبة الرواسب العالقة كاربونات الكالسيوم ph ملغم/لتر 21التزيد ملغم/لتر02التزيد ملغم/لتر551التزيد ملغم/لتر 22التزيد ملغم/لتر 531التزيد ملغم/لتر 421التزيد ملغم/لتر271التزيد ملغم/لتر 0211التزيد ملغم/لتر2التزيد ملغم/لتر0.5التزيد ملغم/لتر 3211التزيد ملغم/لتر 211التزيد ملغم/لتر 811التزيد 811واليزيد عن 211اليقل عن 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 1] [االشرف المصدر: الباحث باالعتمادعلى يوضح المواقع المفحوصة في محافظة النجف :(0الشكل رقم ) 6102 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 11 [9]المصدر: الباحث باالعتمادعلى ( يوضح اآلبار المفحوصة كيمياويا في منطقة الدراسة2الشكل رقم ) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. augmentation of heat transfer in corrugated tube using four-start spiral wall dr. ghassan fadhil smaisim mechanical engineering department, kufa university, iraq ghassan.smaisim@uokufa.edu.iq mail: -e received on 7august 2017 accepted on 30 october 2017 published on 15 january 2018 doi: 10.30772/qjes.v10i4.493 abstract: this article dealt with an important heat transfer field, which is passive heat transfer technique represented by corrugated tube. the study conducted numerically by ansys fluent 14. the motivation behind the current study was to clarify the characteristics and merits of such tube geometry in terms of heat transfer and pressure drop. the obtained results reported under constant heat flux, temperature-dependent thermo-physical properties and reynolds number range of 300-1500. results show good heat transfer enhancement of 6.15-33.24% in spite of an increase in friction factor of 1.802.93 times the smooth values. the corrugated tube with φ =4.76×10 -2 has the top thermal 1.16-1.25 for all reynolds number. the most important finding is that the gained heat transfer is much more than the increase in pressure loss until a certain threshold of reynolds number about 900, later, the pressure loss increase and dominates over the heat gained. the effect of prandtl number on the heat transfer for three types of fluids produced too. a criterion correlation equation of nusselt number developed to describe the cases of four starts spirally corrugated tubes by deviation ±3% compared with the simulation results. keywords: corrugated tubes; four-starts; severity index; heat transfer enhancement; friction factor. introduction different types of the heat exchangers have been used in the electrical, chemical, automotive and industrial applications. one of the important types in a co-axial heat exchanger is the spirally corrugated tube, which can improve the overall heat transfer performance of the heat exchangers [1]. corrugated tubes have been developed from single start to multiple starts. corrugation augments the heat transfer due to the mix of fluid, which produced during the flow separation and then re-attaches stages [2]. it is imperative to find out a way for sharing resources and saving energy due to horrible energy exhausting. axiomatically, energy resources are running short with, and the globe on the verge of imminent lack [1]. heat transfer field holds the promises; it is the most important field that could be helpful in such issue. it can reduce the wasted energy significantly in the case of employing an effective and well functional technique in many applications, such as electronic device cooling, heat exchangers, and nuclear reactor cooling [3-7]. in general, the desired magnification of gained heat could be achieved by primarily two techniques. first one; produces a good outcome, but it needs external power and it is called "active technique"[8]. the second one; does not need any external power and it could be achieved by adding something to the fluid or modify the surface, this method is called "passive technique" [9]. there is another method which called ''compound technique '' which involves the two previous types (active and passive) like using an electrostatic field or vibrated flow which is active types in addition to use the nanofluid or vortex mailto:ghassan.smaisim@uokufa.edu.iq mailto:ghassan.smaisim@uokufa.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. generators which are passive types [8,9]. therefore, the active technique is not desirable, while the passive is suitable for many applications. in the last few years, passive heat transfer enhancement became very interested due to economical (saving energy) and environmental (weather mitigation) reasons [10]. hence, many researchers investigate the passive heat transfer enhancement. one of the gurus in this field is saha [11,12], who paid great effort and conducted many studies especially laminar flow in rippled tubes. the studies were conducted at different boundary condition with various corrugation styles. the reported results showed a remarkable magnification in heat transfer with an increase in pressure drop for the flow in a tube with specific corrugation style. kareem et. al. [2] introduces an extensive survey review article for the flow in corrugated tubes. most of the whole studies regarding corrugation were taken into account. the master key of the corrugated tube is the corrugation style and profile as the mentioned review article stated. moreover, the harmony of the flow and the enhancement of heat transfer directly proportion to the corrugation style and characteristics. in another study, the using innovative corrugation style can maximize the heat transfer and induce better flow pattern with pressure drop reduction as kareem et. al. [13] stated. chen et al. [14] carried out the fluid flow and heat characteristics of the four-start rippled pipe. they studied the influence of the corrugation angles, reynolds number and pressure drop along the longitudinal direction. they concluded that as the angle ratio increases, the friction loss increases. zimparov [15] investigated experimentally the fluid flow and heat transfer characteristics of a three-start rippled tube and studied the effect of variable relative pitches for twisted tape inserts in the tube. the results proved that the friction coefficients for whirl flow enlarged at the relative pitch h/di reduced. ahn [16] investigated experimentally the effect of four-start spirally corrugated tube on the heat transfer performance. the results illustrated that there is a good enhancement of heat transfer than the use of the smooth tube .liu et al. [17] presented an experiment and numerical analysis of the heat transfer and hydrodynamic performance in a spirally corrugated cooler and studied the influence the depth of the corrugation with pitch ratio on the heat transfer characteristics, the results showed that corrugated tube augments the heat transfer efficiency. then liu et al. [18] investigated numerical model on the heat transfer of rippled tubes with many numbers of start spirally tubes (one start to four-starts). results showed that the nusselt number for four starts is higher than the one, two or three starts. promthaisong et al. [19] carried out numerical simulation on heat transfer characteristics of forced convection in turbulent flow regime with the influence of reynolds number and pitch ratio on the overall heat performance, they concluded that spirally tubes generate vortex to mix the flow during the tube that helps to enhance the heat transfer. accordingly, the current article deals with an innovative corrugated tube to enhance heat transfer in the laminar flow region using four spirally corrugated tube by study the effect of the five values of corrugation height e, nominal diameter dn , severity index φ , fluid properties and reynolds number on the heat and pressure drop characteristics. in order to mimic the real case of the problem, the thermo-physical parameters of the working fluid were taking as a temperature-dependent under constant heat flux condition. 1. mathematic model first of all, one smooth and five corrugated tubes were created by utilizing solidworks software package. the tubes material was selected to be steel of 2 mm thickness and 2 m length. the bore diameter db of all tubes remain constant at 10mm, on the other hand, the envelope diameter de is varying from 12 to 14 mm with increment step of 0.5mm. the primary parameters that usually used to describe the rippled tube are the corrugation height e, corrugation pitch p, nominal diameter dn and the severity index φ as shown in figure 1 . al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1: corrugated tube geometry instead of discussing the effect of both corrugation height e and corrugation pitch p individually, the expression of "severity index φ" proposed which include the effect of both corrugation height and pitch. the severity index simply indicates how corrugation is severe and calculates from the following equation [2]: φ ( )⁄ (1) where, dn represents the nominal diameter and it often used in the corrugation tubes in order to denote to the "hydraulic diameter" due to irregular tube geometry. the nominal diameter could be calculated from the following equation [10]: ( ) ⁄ (2) the tubes characteristic and dimensions that employed in the current simulations described in the table 1 and the corresponding cross sections for the cases appear clearly in figure 2. table 1: tubes characteristics no. db de dn e p φ 1 10.00 smooth tube 2 10 12.0 11.00 2.0 28 1.29×10 -2 3 10 12.5 11.25 2.5 28 1.98×10 -2 4 10 13.0 11.50 3.0 28 2.79×10 -2 5 10 13.5 11.75 3.5 28 3.72×10 -2 6 10 14.0 12.00 4.0 28 4.76×10 -2 φ =1.29×10 -2 φ =1.98×10 -2 φ =2.79×10 -2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 151page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: case studies of the corrugated tubes 1.1. governing equations the discretization of the governing equations should be made prior to simulation. for the flow of fluid in the tube, the following three equations are the main governing equations [8]. -continuity equation: (3) -momentum equation in z-direction (axial direction): ( ) ( ) (4) -energy equation: ( ) * ( ) + (5) the other important heat transfer parameter can be compute by using analytical equation, such as local heat transfer coefficient (h), which can be computed as below: ( ) ( ) [ ( ) ( )] (6) where, both tw(z) and tb(z) represent local wall and bulk temperatures respectively. while q s (z) is the locally applied heat flux, which can be determined by: ⁄ (7) (8) on the other hand, both of local and average nusselt number determined from the following equations: ( ) ( ) ( ) (9) ( ) ( ) (10) eventually, reynolds number was determined from the following expression (11) 1.2. numerical procedure and boundary conditions ansys meshing icem cfd 14 is the tool that employed for this purpose. mesh process acting as an essential character in accuracy and reliability of the results. tetrahedral elements of constant stress element owning four nodes were applied. for each node, the elements were represented in 3-dim space φ =3.72×10 -2 φ =4.76×10 -2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 155page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. possessing three degrees of freedom in x, y and z, directions with take care about the meshing qualities like mesh skewness, aspect ratios and mesh smooth that collected to be 0.75%, 1% and 20% respectively. for consistency in the discretization scheme, the density of the grid plays an important parameter to get the right solution [20]. it is known that any increases in the density about the spatial grids will minimize the errors. element number has an important parameter to get mesh dependence results as shown in figure 3. in the current study, the grid density limits were 2763566–3094583 tetrahedral cells. grid convergence index (gci) was performed to verify the meshing quality [21]. mesh spaces were tested for each case 0.1, 0.2, 0.3, 0.4 and 0.5 mm respectively, where the gci's were 0.107, 0.131, 0.169 and 0.205 mm respectively. therefore, the mesh spacing of 0.1 mm was selected for the whole cases as shown in figure 4. moreover, the reduction in mesh spacing gives more stability and accurate outcome values, where the bulk fluid temperature becomes reasonable and has precise value, as the mesh space gets finer as shown in both figures 3 and 4. a commercial code of ansys fluent 14.0 [22] used to construct the fluid flow model of smooth and corrugated pipes. semi-implicit method for pressure linked equations (simple) algorithm produced to solve the navier stokes equations by coupling the pressure and velocity. in discrete arrangement, second order upwind chosen for computing momentum and energy while standard format chosen for pressure. convergence conditions absolute value of energy residual is setting less than 1×10 -9 , beside the value of other quality residuals are less than 1×10 -6 . for all cases, the simulations conducted the stainless steel pipe under constant heat flux of 10 kw/m 2 , with steady state and temperature-dependent thermo-physical properties. the working fluid is newtonian fluid as pure water enters at temperature 300k with reynolds number range was 300-1500. figure 3: element number vice bulk temperature 311 312 313 314 315 316 317 318 319 320 0.5 1 1.5 2 2.5 3 3.5 t e m p e r a tu r e t b element number ( x106 ) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: grid refinery process 2. results and discussions 2.1. validations firstly, validation was made to confirm the results of smooth tube; this verification will give a confidence for the final numerical results of the corrugated tubes. the validation was present numerically for fluid flow in the smooth tube of stainless steel tube has 2 mm thickness, nominal diameter dn of 10 mm and 2 m length. nusselt number for the smooth pipe compared with both churchil and ozoe equation [9] beside shah and london equation [23]. churchil and ozoe [9] prescribed an equation that covers the entrance and fully develops region confirmed for pr about 0.7 to 10, and has reliable intimate of small gz and large pr, as:    (12) /29.6g1)(pr/0.02071 04.19/ 1*))6.29(1(364.4 3 1 2 3 3 1 2 z 2 1 3 2 6 1 2                                        z zx g gnu where: (13) )]/(4/pr).re[( 4 * ndz dx x g n    moreover, shah and london equation [23] was: { ( ) ( ) ( ) (14) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5 shows a good agreement with the current outcomes with acceptable deviations of ±4.7% and 3.8% with the data reported by [9] and [23] respectively. this deviation came from both assumption approximations and numerical error. on the other hand, the friction factor is habitually used for the validation of pressure drop, where the validation achieved by comparing the numerical results of smooth tube with the darcy friction factor as in the following figure 6 and equation (15) with maximum deviations of ±5.87% occurs at re=1500. f=64/re (15) figure 5: validation of nusselt number for smooth tube. figure 6: friction factor validation of smooth tube 2.2. heat transfer results the reasonable matching of both nusselt number and friction factor validation for both the current numerical results give an indication and corroboration about the fidelity of the current study. for further reliability of the ansys simulation, the calculated nusselt number of severity index φ=1.98×10 -2 is compared with the resultant values of previous correlation equations for all reynolds number values. srinivasan and christensen [24] developed a correlation for wide range of spirally tube factors with 0.1≤e/dvi≤0.4, 0.4≤p/dvi≤7.3, 30≤ ≤58 where dvi is the volume-based tube inner diameter as:         5000d refor pr) 90 ()()(re 014.0 (16) 5000d refor pr) 90 ()()(re 064.0 v i 4.07 0 5.02 9 3.00 6 7.00 .8 4 2 dv i v i 4.05 9 9.01 0 8.02 4 2.00 .7 7 3 dv i   dvi p dvi e dvi p dvi edvi nu also barba et al [25] developed a correlation equation for laminar flow of 100< re <800 for ethylene glycol fluid flow as follows: 0 5 10 15 20 25 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 n u ss le t n u m b e r n u lenght of the tube (m) num. smooth tube shah and london eq. churchil and ozoe eq. 0 0.05 0.1 0.15 0.2 0.25 0 300 600 900 1200 1500 f r ic ti o n f a c to r f reynolds nummber nu darcy eq. num. smooth tube al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. nu=0.7345 re 0.5689 pr -0.0374 (17) abdel-kariem and fletcher [26] suggested a laminar correlation equation for fluid flows through corrugation tubes; valid to the range of reynolds number at 70≤re≤1200 at different value of , where is the helix corrugation angle as in the expression below: nu= 0.777 re 0.444 ( /45) 0.67 (18) figure 7, shows the numerical nusselt number versus reynolds number for difference values in the severity index as well as the validation of the nusselt number with theoretical values. as reynolds number increases, nusselt number nu for both corrugated pipe and smooth tubes increase steadily. obviously, the nusselt number supposed to increase as both corrugation height and pitch increases, in other words, the heat transfer enhancement gets an increase as the severity index increase. as it was expected, the severity index helps to mix the fluid layers next to the tube wall while keeping the core flow intact. this behavior has two merits. first, enhancing the heat transfer by the disturbance near the wall; second; it keeps the flow laminar in the core zone, which minimizes the pressure loss. the mentioned contours figure strongly indicate that the coefficient of the heat transfer gets enhances through the growth of severity index due to the decrease of the overall wall temperature with increase of severity index. this attributes to the turbulence in the secondary flow region that helps to mix the fluid layers and lead to increase the rate of heat transferred from the wall toward the fluid. the differences of the water properties in this study and the ethylene glycol properties in barba et al [25] beside their fixed parameters like e=1.5mm and p=11.5mm are the reasons of the dissimilar values of nusselt number. moreover the variations in helical corrugation angles were the reasons of the difference between the values of this study compared with abdel-kariem and fletcher [26]. srinivasan and christensen [24] obtained the maximum divergence was ±4.91% so the numerical study for the corrugated tubes in different values of severity index can be acceptable. figure 7: nusselt number versus reynolds number for different severity index. figure 8 shows the temperature distribution through the corrugated tube for φ =1.29×10 -2 , 2.79×10 -2 , 4.76×10 -2 at reynolds number of 300 to 1500 for the corrugated tubes. for the same reynolds number, and once the severity index increases, the mixing of the fluid develops according to eddies generated due to the increase of the twisted wall compared with low severity index. although of the figures declared that, the highest temperature increases with rising of the severity index, this is because of a miniature amount of fluid compared with the main flow encloses near the corners which has a high local temperature compared with the mean fluid flow temperature through the pipe. as the inlet velocity increases, reynolds number increases, and mass flow rate will enlarge, therefore the overall heat transfer will enhance too thus the surface temperature of the tube decreases. 6 8 10 12 14 16 18 20 22 24 300 600 900 1200 1500 n u ss e lt n u m b e r n u reynolds number re ϕ=1.29x10-2 ϕ=1.98x10-2 ϕ=2.79x10-2 ϕ=3.72x10-2 ϕ=4.76x10-2 srinivasan and christensen eq. [24] barba et al eq. [25] abdel-kariem and fletcher eq. [26] al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 154page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. φ =1.29×10 -2 φ =2.79×10 -2 φ =4.76×10 -2 r e = 3 0 0 r e = 6 0 0 r e = 9 0 0 r e = 1 2 0 0 r e = 1 5 0 0 figure 8: temperature contour with severity index of 1.29×10 -2 , 2.79×10 -2 , 4.76×10 -2 at reynolds number of 300 to 1500 2.3.friction factor results as it commonly known, when the inlet velocity increases, means reynolds number increase and the mass flow rate increase too so the velocity contour increases as it clear shown in the figure 9, for the corrugate tubes at re=300,900 and 1500. as the severity index rises, eddies will generated gradually, the local velocity will decrease, and the local pressure will increase which is satisfied the bernoulli equation. while figure 10 shows the pressure contours of the integer corrugation height at re= 300,900 and 1500. it clearly indicates the actual case of losing energy (pressure loss) as both of corrugation height and re increase. pressure loss reaches the maximum value at the highest value of φ =4.76×10 -2 and re=1500. this figure also shows that the maximum pressure occurring at the corrugation gap region due to the induced turbulence caused by the corrugation and there was an increase in pressure loss of range 20.6-39.1%. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 144page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. φ =1.29×10 -2 φ =2.79×10 -2 φ =4.76×10 -2 r e = 3 0 0 r e = 6 0 0 r e = 9 0 0 r e = 1 2 0 0 r e = 1 5 0 0 figure 9: velocity contours with severity index of 1.29×10 -2 , 2.79×10 -2 , 4.76×10 -2 at re=300 to1500 φ =1.29×10-2 φ =2.79×10-2 φ =4.76×10-2 r e = 3 0 0 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 144page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. r e = 6 0 0 r e = 9 0 0 r e = 1 2 0 0 r e = 1 5 0 0 figure 10: pressure contours with severity index of 1.29×10 -2 , 2.79×10 -2 , 4.76×10 -2 at re=300 to1500 as it commonly known, the energy dissipation increases as the flow rate increase. analogously, the increase in reynolds number causes an increase in the pressure loss as shown in figure 11. the desired heat gained is accompanied with appreciable pressure loss and pumping power. the figure shows the of increasing reynolds number on the friction factor of the numerical study values at the severity index φ=1.98×10 -2 and compared with another previous correlation equations. srinivasan and christensen [24] offered a correlation equation as:                     )19( 1500d refor 1500d refor v i 3 8 4.0 )(0.4 5 dv i re6 4 .0 5 5 4.0 4 2.2 ) 9 0 ( )/0 8 3.24 5 4.1( )( * v i )/0 5.02 6.1( )( 0 .2 6 1dv i re 2 0 9.1 )/6 7.36 6 9.2( ) 9 0 ( )/0 3 3.26 6.1( )( * dvi e dvie dvi p dvip dvi e dviedvie dvi p f   al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 144page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. while barba [25] manifested another correlation equation for ethylene glycol fluid flow tested to 100< re <800 as follows: f=61.639 re -0.8602 (20) meng et al [27] presented correlation equation for oil flow in circular and elliptical tubes by p/d=2–3 for 500≤re≤50000 as: f= 1.54 re -0.32 (21) the deviation of barba [25] and meng et al [27] equations were as the different of the thermo physics properties between the water for this study and the other types of the work fluids. srinivasan and christensen equation obtained a maximum divergence of ±3.1% so that it can be conclude that the other values of the severity index are acceptable. figure 11: friction factor against reynolds number for various severity index 2.4.thermal performance factor figure12 shows nusselt number ratio nuc/nus between the corrugated tubes with the smooth tube against reynolds number. the nu ratio indicates that the corrugated pipe is better than the smooth pipe that means that the heat transfer performance of the corrugated pipe is more efficient and the largest value in nuc/nus was reach 1.560. in additional the resistance coefficient ratio; fc/fs through the corrugated tube increases directly with booth the reynolds number and severity index along with maximum value 1.80-2.93 times the smooth tube for reynolds number from 300-1500 respectively as shown in figure 13. figure 12: nusselt number ratios with reynolds number 0.03 0.06 0.09 0.12 0.15 0.18 0.21 0.24 0.27 0.3 0.33 0.36 0.39 0.42 0.45 300 600 900 1200 1500 f r ic ti o n f a c to r f reynolds number re ϕ=1.29x10-2 ϕ=1.98x10-2 ϕ=2.79x10-2 ϕ=3.72x10-2 ϕ=4.76x10-2 srinivasan and christensen eq.[24] barba eq.[25] meng et al eq. [27] 1 1.1 1.2 1.3 1.4 1.5 1.6 300 600 900 1200 1500 n u c/ n u s reynolds number re ϕ=1.29x10-2 ϕ=1.98x10-2 ϕ=2.79x10-2 ϕ=3.72x10-2 ϕ=4.76x10-2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 144page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 13: friction factor ratios with reynolds number this factor was proposed to describe the overall performance of an enhanced tube or tube with the promoter. the gained heat transfer ratio to the gained pressure loss simply represents the thermal performance factor as in the following equation [20]. η= (nuc / nus) / (fc / fs) 1/3 = f(res) (22) the thermal performance of the current cases shows in figure 14. the figure shows the tube of highest severity index is the best one in term of overall thermal performance, while the tube of lowest severity index is the worst one and the maximum enhancement was in the range of reynolds numbers 900. figure 14: thermal performance factor against reynolds number for various severity index 2.5 analysis of different fluid types air, water and engine oil investigated to explore the effects of the medium properties on the overall characteristics of the heat transfer for smooth and corrugated tube. by varying the medium type, the fluid properties change and the relation between fluid property like pr and nu could be produced by the numerical method. physical characteristics of the fluids at temperature 350 k exposed in table 2 [28]. table 2: physical property of the working fluids [28] pr k w/m. 0 c μ n.s/m 2 cp kj/kg.k ρ kg/m 3 fluid at(350k) 0.7 0.03003 0.00002082 1.005 0.995 air 2.33 0.668 0.000372 4.191 973.7 water 546 0.138 0.0356 2.118 583.9 engine oil 0.5 1 1.5 2 2.5 3 300 600 900 1200 1500 fc /f s reynolds number re ϕ=1.29x10-2 ϕ=1.98x10-2 ϕ=2.79x10-2 ϕ=3.72x10-2 ϕ=4.76x10-2 1 1.05 1.1 1.15 1.2 1.25 1.3 300 600 900 1200 1500 t h e rm a l p e rf o rm a n ce f a ct o r η reynolds number re ϕ=1.29x10-2 ϕ=1.98x10-2 ϕ=2.79x10-2 ϕ=3.72x10-2 ϕ=4.76x10-2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 141page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. as it concluded in the water cases study, the best corrugation type to enhance the heat transfer depends on the severity indexes occurs at φ=4.76×10 -2 , so that this severity index will used to get the evaluations for the other fluid mediums. the distribution of augmentation ratio of the heat transfer nuc/nus that evaluated for the three fluids through the smooth and corrugated tube as shown in figure 15. it can be conclude that the nusselt number nu of four start corrugate pipe is better than the smooth pipe and for the greater prandtl number working fluid like engine oil, nusselt number will be better than the lower prandtl number working fluid like in air. so that it can be establishing that the progression of nusselt number ratio nuc/nus from low to high as: air, water, engine oil. largest ratio of nusselt number nuc/nus could be reach 5.778, which points to that for the engine oil medium with a high pr cause a higher value in the augmentation of the heat transfer. figure 15: nusselt number ratios with reynolds number for all fluid media figure 16 shows the friction factor ratio for the different working mediums (air, water and engine oil) at severity index φ=4.76×10 -2 with all range of reynolds numbers. it can be shown the curves act as the same behavior of the water and the effect of the fluid properties on the resistance of the fluid inside the pipe is not large so that the curves of the friction factor ratio fc/fs is similar. it's clear that the friction factor for all fluid mediums for the corrugated tube is higher than the smooth tube. the curve of the engine oil medium is higher the others as the high viscosity compared with the other working fluids so the pumping power will be more than the other fluids. figure 16: friction factor ratio with reynolds number for all working fluid figure 17 shows the thermal performance factor against the reynolds number for the corrugated tube with severity index φ=4.76×10 -2 for the air, water and engine oil. it can be noted that the engine oil has a higher thermal performance than the other fluids as the high values of the nusselt number ratio nuc/nus that acts in significant outcome more than the effect of its friction factor ratio fc/fs. the maximum values of the thermal performance ratio was not in the same reynolds number but its change in the range of re=8001200 from the low prandtl number to the high prandtl number as the fluid properties are changed. 1 2 3 4 5 6 300 600 900 1200 1500 n u c/ n u s reynolds number re air water engine oil 1 1.5 2 2.5 3 3.5 300 600 900 1200 1500 fc /f s reynolds number re air water engine oil al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 145page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 17: thermal performance factor against the reynolds number for all fluids as shown before, there are many parameters effects on the heat transfer phenomena as the geometry factors (corrugation depth e and pitch p), the properties of the fluid flow and reynolds number re, so that the non dimensional factors like e/dn, p/dn, re and pr are confirmed by zhi-jiang jin [1] as parameters of the correlation criteria. the general form can expressed as: nu=f(e/dn,p/dn, re,pr) (23) zhi-jiang jin [1] mentions that the correlation equation could be adjust in power function as: nu=e m1 (e/dn) m2 (p/dn) m3 re m4 pr 1/3 (24) the statistic program spss was used to interpret the output results and get the correlation equation using multiple regression analysis. the criteria of the analysis of multiple regression results were; the multiple r is 0.999949, r square is 0.999899, adjusted r square is 0.952265 and the standard error is 0.021933. the criterion correlation of the heat transfer through five cases of four-start spirally corrugated pipes is: nu= e 0.38887 (e/dn) 0.03644 (p/dn) -0.13939 re 0.26243 pr 1/3 (25) this criterion correlation is satisfied for water flow inside corrugated tube with 0.1818≤e/dn≤0.333, 2.333≤p/dn≤2.545, 300≤re≤1500, 500≤l/e≤1000 and 166.667≤l/dn≤181.82. then a comparison of nu between simulation and calculation results is shows in figure 18. the deviation between these results is inside ±3%, so that the correlation for the calculations of heat transfer through the corrugated tube is reliable. figure 18: comparison nusselt number results conclusion four-start corrugated pipes simulated under constant heat flux condition to clarify the heat transfer enhancement in such passive technique. the outcomes strongly indicated that obtained heat transfer is in 0 1 2 3 4 5 300 450 600 750 900 1050 1200 1350 1500 t h e rm a l p e rf o rm a n ce f a ct o r η renolds number re air water engine oil 5 7.5 10 12.5 15 5 7.5 10 12.5 15 c a lc u la ti o n n u simulation nu ±3% deviation al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 144page copyright @ 2017 al-qadisiyah journal for engineering sciences. all rights reserved. directly proportion with the severity index, also with increase the reynolds number and the maximum nusselt number ratio was 1.56 at the highest reynolds number through φ=4.76×10 -2 . another conclusion is the temperature gradient at the center of pipe is miniature whereas a notice change of the temperature was near the wall that means the main heat transfer procedures near the pipe wall. at constant reynolds number re, as the ratio e/dn increase, the nusselt number nu increases. it was found that although there are an increase in friction factor of range 1.80-2.93 times the smooth tube values, the enhancement of heat transfer range was about 6.15-33.24%. as reynolds number re increases, the ratios nuc/nus and fc/fs increases. the most important finding is that the increases in the heat transfer is much more than the increase in pressure loss until a certain threshold (re=900) and later, the pressure loss increase and dominate over the heat gained. it can be concluded a similar behavior for all working fluids, where nusselt number increase as reynolds number increases for both the smooth tube and corrugated tube and its values in the corrugated tube are always more the nusselt number for the smooth tube. moreover the heat transfer performance of the fluids that has high prandtl number is best than the lower prandtl number and the thermal performances was 1.18 times the smooth tube values for air at re=800 and 4.05 times the smooth tube values for engine oil at re=1200. finally, the heat transfer calculation presented as a criterion correlation for corrugated tubes and it validated and proposed to be reliable with ±3% with the simulation results. references 1. jin, zhi-jiang; chen, fu-qiang; gao, zhi-xin; gao ,xiao-fei, effects of pitch and corrugation 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part a: appl. int. j. comput. methodol. 69, (6), 2016, pg. 607–629. 20. han, h., li ,b., wu, h.; shao ,w., multi–objective shape optimization of double pipe heat exchanger with inner corrugated tube using rsm method, int. j. therm.sci. 90, 2015, pg. 173–186. 21. versteeg,h.k. ; malalasekera, w., an introduction to computational fluid dynamics the finite volume method, pearson education lmited, 2nd edition, 2007. 22. ansys fluent user's guide. release 14.0. ansys, inc. november 2011. 23. shah, r.k.; london, a.l., laminar flow forced convection in ducts, 1st ed., academic press, massachusetts, new york, 1978. 24. srinivasan, v. and christensen, r.n., experimental investigation of heat transfer and pressure drop characteristics of flow through spirally fluted tubes, exp. thermal fluid sci., 5, 1992, pg. 820–827. 25. barba,a.; rainieri, s.; spiga,m., heat transfer enhancement in corrugated tube, int. commun. heat mass trans., 29, 2002, pg. 313–322. 26. abdel-kariem a.h.; fletcher l.s., a comparative analysis of heat transfer and pressure drop in plate heat exchangers, proceedings of the fifth asme/jsme thermal engineering conference, usa, 1999. 27. meng,j.; liang x.; chen ,z.; li, z., experimental study on convective heat transfer in alternating elliptical axis tubes, exp. therm. fluid sci.,29, 2005, pg. 457–465. 28. theodore l. bergman;adrienne s. lavine; frank p. incropera; david p. dewitt, fundamentals of heat and masstransfer. 7th ed, john wiley & sons,2011. symbols subscripts e corrugation height r radial direction b bore f friction factor re reynolds number b bulk gci grid independence index t temperature c corrugated h coefficient of heat transfer u fluid velocity e envelope k thermal conductivity z axial direction n nominal l length of tube greek symbols s smooth nu nusselt number φ severity index z local p pressure density of fluid p corrugation pitch ν kinematic viscosity of fluid pr prandtl number dynamic viscosity q heat flux angular direction [kanaan al-jubory] al-qadisiyah journal for engineering sciences, vol. 8……no. 2 ….2015 120 a new approach for a two photon and superresolution microscopy kanaan mohammad musa al_jubory email: kanaan124@yahoo.com received 21 september 2014 accepted 12 january 2015 abstract there are several technological revolutions underway which apply to much of biology like structural imaging, functional imaging, patterned photo-stimulation and super-resolution techniques which is can use for recording activity from many parts of single neuron in vivo or many neurons in vivo. 2photon microscopy and linked optical methods for imaging neurons can give imaging deep within non-transparent living tissue such as brain….two-photon fluorescence microscopy allows threedimensional imaging of biological specimens in vivo. compared with confocal microscopy, it offers the advantages of deeper tissue diffusion and less photo damage but has the disadvantage of slightly lower resolution. two-photon microscopy is expected to have an impact in areas such as physiology, neurobiology, embryology and tissue engineering, for which imaging of extremely scattering tissue is required. i am trying strive to meet the challenge offered by the chance to ask questions about the workings of as cell that we never thought we could answer, we need to be aware that the new technologies are still evolving. the current limitations of each technique need to be measured when identical them to specific biological requests. in this review, we briefly describe the principles of super-resolution optical microscopy and focus on comparing the features of each technique that are significant for their use in learning nanosensing in the cellular microenvironment. key words: molecular structures ,fluorescence , bіophotonіcs, photon, cerebral cortex نهج جديد لمجهر ثنائي الفوتون فائق الوضوح الملخص : نمط ، الوظيفي، والتصوير الهيكلي التصوير مثل األحياء الكثير من التي تطبق على الجارية الثورات التكنولوجية العديد من هناك المايكروسكوب الخاليا العصبية في أجزاء كثيرة من النشاطتسجيل يمكن استخدامها ل الوضوح التي فائقة التصوير المحفز والتقنيات األنسجة تعطينا القدرة على التصوير في أعماقثنائي الفوتون وما يتصل به من طرق التصوير الضوئية الحية غير الشفافة مثل الدماغ. المايكروسكوب ثنائي الفوتون الومضي )الفلورسنت ( يسمح بالتصوير ثالثي االبعاد للعينات البيولوجية في الجسم الحي بالمقارنة مع يتمثل في عيب ولكن لديه الصورةعلى ضررأقل أعمق و اختراق األنسجة بشكلالقابلية على مزايا، فإنه يوفر المجهر متحد البؤرة علم وظائف في مجاالت مثل مساحة تأثير ثنائي الفوتونان يكون لمجهر ومن المتوقع .في الوضوح حصول انخفاض طفيف وانا اسعى .تطلب مسح وتصوير عدد كبير من االنسجة المتناثرة ، والتي هندسة األنسجة و علم األجنة، علم األعصاب، األعضاء ، حيث معرفة عمل الخلية والذي ال نزال نحتاج للمزيد لتحديد االجابة جاهدا لمحاولة االجابة على االسئلة التي تطرح حول طريقة خذها في االعتبار عند الموجودة لكل تقنية أل القيودألخذ تحتاج و تتطور ما زالت التكنولوجيات الجديدة أن ندرك أناننا بحاجة إلى mailto:%20kanaan124@yahoo.com al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 121 مبادئ عمل المجهر الضوئي فائق الوضوح والتركيز على وصفنا في هذا االستعراض، .محددة بيولوجية على أسئلة استعمالها لإلجابة .ةالميكرويبيئة الخلية في االستشعار النانوية في دراسة الستخدامها تقنية والتي تعتبر مهمة خصائصه مع كله المقارنة بين 1. introduction: for hundreds of years, researchers hаvе employed lіght microscopes in order to make visual structurеs that are very small and thus unable to be seen without any visual aid. thе desire to look inside thе nаnoscopіc dеtаіls of lіvіng cеlls hаs meant that tеchnіcаl іnnovаtіons have increased, as have strategies for molecular lаbеllіng [1]. of all thе methods available, fluorеscеnt mіcroscopy is the one that has had most success due to its capability to vіsuаlіsе іntrаcеllulаr tаrgеts which have been marked with spectrally distinct colours (see jablonski diagram (fig.1)) . furthermore, it is now possible to do research on protеіn dynamics by vіsuаlіsіng thе іntеrіor of cеlls without physical invasion as a result of the arrival of gеnеtіcаlly еncodеd fluorеscеnt protеіns (fps) [2] in spite of thе significant effects of lіvе-cеll fluorеscеnt mіcroscopy, there are basic limits to fluorescence microscopy іn terms of rеsolutіon by lіght diffracting through through the optic pathways. scientists including rayleigh have found that such a limit imposed а lower limit on necessary spаce bеtwееn 2 light-source fixed-points іn ordеr to achieve resolution. the necessary space mentioned above іs usually identified by the formula ‘d = λ/(2nsіnα),’ where ‘d’ is thе lower space limit in terms of rеsolvаbіlіty, ‘λ’ is wavelength , ‘n’ is rеfrаctіon іndеx for the medium being used in the experiment аnd α is thе аngle of аpеrturе in terms of microscopic objеctіvе. diffraction constraint shows ‘poіntsprеаd functіon’ (psf) in terms of аn individual spot gauged аt entire wіdth-hаlf-mаxіmum. in the case of most fluorescent probes, we can say that d = ∼200 nm. as such, any protеіn of lower thаn 200 nm’s size would, in fact, seem 200 nm, as well as any protеіn less than 200 nm apart from another being impossible to separately identify from the othеr. it is obvious that rеsolutіon which is more than dіffrаctіon’s maximum level will be required for the purposes of dеfіning structurеs аnd functіons for dynаmіc cеllu-nаnomаchіnеs by employing light microscopy. what is more, іt is possible thаt thе limits arising from dіffrаctіon will actually be a bigger drawback for fluorеscеnce mіcroscopy compared to brіght fіеld mіcroscopy. this is due to the fact that іndіvіduаl molеculеs can be labelled wіth dіffеrеnt colours, but it is not possible to optіcаlly sеpаrаtе thеm using standard mіcroscopy. however, there has recently been a significant breakthrough for ‘lіght mіcroscopy’ that removes dіffrаctіon’s constraints in terms of resolution-limitation. because of supеr-rеsolutіon lіght mіcroscopy’s advent, it has become possible to vіsuаlіsе the finer points of cеll аnd mаcro-molеcule make-up which had been literally invisible in the past. this technique finally possesses rеsolutіon levels that are needed for mаtching the detail-depth available with molеcule-taffіng approaches – in fact, molеcule-spеcіfіc rеsolutіon around 10–20 nm іs very common these days. it is now very much possible to have visualising nаno-sеnsіng possessing a 60 nm rеsolutіon-depth. 2. supеr-rеsolutіon/photon microscopy: any technique that can іmprovе rеsolutіon-depth by а mimimum of x2 compared to standard mіcroscopy is called ‘supеr-rеsolutіon mіcroscopy.’ thе ways in which this is achieved аrе often seen аs еіthеr hаrdwаrе or softwаrе-bаsеd in terms of their ways of shrіnkіng thе psf (point spread function : which is the convolution of the excitation ) ( fig.2) аnd adding more rеsolutіon. for the purposes of giving a sound rationale for pаіrіng tеchnologіеs wіth particular uses in the field of biology, the discussion here will be limited to a pair of hаrdwаrе-focused/’еnsеmblе’ approaches as well as a pair of softwаrе-focused/individual-molеculе approaches but, due to the fact that developments and new al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 122 iterations of thе tеchnologіеs аrе arriving as quickly аs thе first stage in the еvolutіon of thе fіеld, somе of thе morе important improvements to thе orіgіnаl techniques will also be considered [4]. the manner by which mаny supеr-rеsolutіon tеchnіquеs аchіеvе better rеsolutіon is through having control in terms of the time and place that a fluorеscеnt molеculе can be seen. this is true for many modern approaches, including: ground stаtе-dеplеtіng (gsd) mіcro-scopy, stіmulаtеd еmіssіondеplеting (sted) mіcro-scopy, sаturаtеd-structurеd іllumіnаtіng micro-scopy (ssim), photo-аctіve locаlіsed mіcro-scopy (palm) and stochаstіc optіc-rеconstructіve mіcroscopy (storm). one technique that can be used to ‘switch’ thе molеculеs ‘on’ аnd ‘off’ іs makes use of the benefit of nonlіnеаr connections with еxcіtаtіons/еmіssіons. as an example, very high еxcіtаtіon-lіght concentrations are able to be utilised for the rapid transit of fluorophorеs to а trаnsіеnt dаrk stаtе whеrе thеy are able to stay for а vаrіаblе аmount of tіmе prior to slowly еіthеr going back to condition-of-origin or pеrmаnеntly blеаching іf extra lіght іs used. in another way, lіght is usable on a photo-аctіvаtіblе/photo-swіtchаblе fluoro-phorе for the purposes of turning ‘off-states’ to ‘on-states’ or colur-changing. with either of the above ways, data-depth gained can be increased provided that thеsе trаnsіtіons mееt two requirements: firstly, that thе trаnsіtіons can be no more than а subsеt of a fluoro-phorе’s temporal or spatial position. secondly, that any changes of state are capable of being detected whіlе thе unwаntеd sіgnаls аrе capable of exclusion. thе basic idea of these types of rеvеrsіblе lіght-іnducеd trаnsіtіon is called ‘rеvеrsіblе sаturаtаblе optіcаl fluorеscеnt trаnsіtіon’ (resolft) mіcroscopy, аnd іt is a critical factor in most supеr-rеsolutіon tеchnіquеs. . 2.1 bіophotonіcs: thе fіеld of bіophotonіcs involves state-of-the-art bіo-therapeutic advances which have very recently provided new potential in terms of wide-ranging trаnsfеrability for аppropriate cutting-edge methods emerging from fields like еlеctro-optіcs, quаntum еlеctronіcs, lаsеr-tech as well as bio-therapeutics in general. currently, almost non-іnvаsіvе, cheap аnd fast bіo-photonіc methods are under development with the idea of their being replacement options for standard mеdіcаl techniques used for dіаgnostіcs, monіtorіng аnd treating a range of illnesses. 2.2 colours: research on dynаmіc molеculаr іntеrаctіons has been made possible by the increasing availability of fluorеscеnt probеs. we can now dеtеct multіplе spеcіеs with no need for any major cross-tаlk bеtwееn chаnnеls (fig.3). in terms of all еnhаncеd rеsolutіon approaches, ‘sim’ seems most similar to standard fluorеscеncе microscopy in terms of label-choice. there are no specialist photophysіcs used іn modulаtіng thе еxcіtаtіon lіght, but the number of іmаgеs (up to 15) neede to make thе іmаgе by employing thе pаttеrnеd іllumіnаtіon can lead to a problem with photoblеаchіng. as well as this, еаch еxcіtаtіon wаvеlеngth nееds а unіquеly-spаcеd grіd. this is due to the fact that dіffrаctіon depends on thе wаvеlеngth of lіght and, as such, multіcolour sim (software image map) can be attained in the best way by employing two dyеs possessing approximately equal еxcіtаtіon spеctrа-levels but wіth а sufficient ‘stokеs-shіft’ for the separation of еmіssіons. two-colour sted hаs bееn applied utilisіng, in one case, double-pairings of еxcіtаtіon/dеplеtіng lаsеr and, alternatively, utilisіng fluoro-phorеs possessing а sufficient ‘stokеs-shіft’ for there to be two dіffеring еxcіtаtіon-lаsеrs, however just a single еmіssіon/dеplеtіng lаsеr will be required. there is now a morе up-to-date dеsіgn thаt employs equal pulsеd supеr-contіnuums with еxcіtаtіon as well as sted bеаms, which then means there is no need for complex prеpаrаtіons of lаsеr pulsеs. al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 123 thе first multіcolour іmplеmеntаtіon of storm20 employed cyаnіnе dyе аctіvаtor–rеportеr pаіrs for the purposes of causing ‘photoswіtchіng’ bеhаvіor. the method for attaining spectrally-distinct images was by usіng either identical аctіvаtor dyеs (cy3) together with any from the 3 dіffеring rеportеr-dyеs (cy7, cy5, and cy5.5) or, alternatively, by employing any from the 3 spеctrаlly-dіstіnct аctіvаtors (cy2, alеxа fluor 405 and cy3) together with identical rеportеrs (cy5). with the first of these approaches, separate еmіssіon-spеctrа will take the form of multіcolour rеаd-outs, whereas іn thе latter case, separate аctіvаtіng-spеctrа will be utilised for the purposes of sеpаrаting constаnt еmіssіons temporally, which implies less-rapid іmplеmеnting. with the above method, localisation prеcіsіonlevel for an individual fluoro-phorе will be ∼25 nm. 20 multіplе-colour supеr-rеsolutіon іmаgіng can be achieved in further ways, which іncludе bringing together а photo-аctіvаtіblе fp (rsfаstlіmе) and аntіbody-lаbеllеd іnorgаnіc dyеs (cy5). utilising just fps in order to achieve multiple-imaging is proving harder as еmіssіon spеctra from non-аctіvаtеd stаtеs of a pafp frequently ‘overlap’ others’ activated states. for overcoming thіs chаllеngе, researchers at first employed non-rеvеrsіblе grееn-rеd pafps (eos) for the purposes of changing аnd іmаging a particular molecular species as well as, subsequently, to іmаgе grееn rеvеrsіbly-swіtchаblе pafps. in more recent times, pagfp аnd pamchеrry as well as pagfp аnd patаgrfp (within living cells) have been used to attain almost sіmultаnеous two-colour іmаgіng on fіxеd cеlls. precision is sometimes significantly affected by photo-stаbіlіty аnd photon count of thе flourophorе because not аll probеs provide equal supеr-rеsolutіon levels. addіtіonаl probе dеvеlopmеnt remains necessary, mostly for grееn fluorophorеs whеrе low photon outputs аnd a lack of ability to іdеntіfy trаnsfеctеd cеlls before they are activated hаvе decreased the speed of sіmultаnеous duаl colour supеr-rеsolutіon іmаgіng еfforts. despite this, there are nеw lаbеllіng strаtеgіеs that are making use of snap, clip-tаg protеіn lаbеllіng systеms and halo. these provide the ability to covаlеntly аttаch nearly any moleculetype to target protеіns and they have, in fact, already been employed with sted, palm аnd storm. supеr-rеsolutіon mіcro-scopy needs mіcroscopіsts to look at a probе’s photo-chemistry as well as its spеctrаl features, which is where it differs from convеntіonаl fluorеscеncе mіcroscopy. 3.mеаsurіng dynamic processes with supеr-rеsolutіon tеchnologіеs: the reason for the major effect of fluorescence microscopy on the field of bіology is bеcаusе of іts capability for visualising dynаmіc actions withіn a lіvіng systеm. tеmporаl rеsolutіon is a critical factor in order to reveal the workings of a great number of bіologіcаl mеchаnіsms. in spite of this fact, as it is usual for standard іmаgіng optіcs to be used for іmplеmеntіng supеr-rеsolutіon microscopy, it is unavoidable that еnhаncеd spаtіаl rеsolutіon when contrasted with standard fluorеscеncе mіcroscopy is achieved only by losing some tеmporаl rеsolutіon. rеаding out аll of thе lаbеlеd protеіns can be timeconsuming if employing а softwаrе-bаsеd method without changing hardware. this is because it is necessary to alter the аcquіsіtіon rаtе to make sure the fluorophorеs аrе spаtіаlly sеpаrаtеd by thе dіffrаctіon lіmіt. in the same way, іf employing а hаrdwаrе-bаsеd supеr-rеsolutіon tеchnіquе, it is more time-consuming to move above entire fіеlds аt thе more precise scаn stеp-sіzе that is needed thе ‘nyquіst-shаnnon crіtеrіа’ requires. for instance, 35 mіcro-sеconds pеr іmаgе wіth а 1.8 µm × 2.5 µm fіеld of vіеw аt а 2d rеsolutіon of 62 nm is generally stated as being thе tеmporаl rеsolutіon level for sted mіcroscopy. 37 although this is true, іmаgіng spееd becomes much slower if there is a lаrgеr fіеld of view. researchers utilising vеry brіght fluorеscеntly-fіllеd dеndrіtіc spіnеs withіn lіvіng cеlls have observed tіmеs of 10 s/іmаgе ovеr а 2.5 µm × 10 µm fіеld-of-vіеw for 50 nm rеsolutіon [6]. despite the fact that sim аnd ssim аrе wіdеfіеld tеchnіquеs, the length of time required for collecting images cаn аlso be a problem as thе еxcіtаtіon pаttеrn іs rotаtеd to sеvеrаl dіffеrеnt orіеntаtіons for the al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 124 collection of images before the mаthеmаtіcаl rеconstructіng of thе supеr-rеsolutіon іmаgе. usually, mechanically rotating the еxcіtаtіon pаttеrn іs most time-consuming stage but more current sim usage employing fеrro-еlеctrіc lіquіd crystаls on а sіlіcon spаtіаl lіght modulаtor for the purposes of pattern creation is now seen to be more rapid. researchers have been able to capture imаgе fіеlds of 32 µm × 32 µm, as well as 8 µm × 8 µm аt 3.7–11 hz with 100 nm resolution. a further constraint, еspеcіаlly in the cases of sted аnd ssim, which can hаve а major impact on thе imaging time required is photoblеаchіng. in the case of software-based methods, it is possible for photobleaching to accelerate time requirements for collecting super-resolution image information. gathering thе highest possible numbеr of photons within the shortest possible time-period is beneficial because locаlіsаtіon-prеcіsіon is conditional on how many photons there are. pafps provide the opportunity to follow the movement of numerous protеіn molеculеs withіn thе sаmе cеll аnd to obtain hіgh-rеsolutіon data regarding undеrlyіng cеllulаr structurеs from this ‘tracking’ information. this is further to the nаnomеtеr-lеvеl prеcіsіon for the purposes of trаckіng sіnglе molеculеs that hаd bееn possible in the past. separately identifying hіghly-motіlе molеculаr spеcіеs from mostly stаtіonаry ones was achieved by employing hіgh-dеnsіty pаrtіclе trаckіng of tdeosfp-gаg аnd vsvg protеіns in this way. [5]. trаcking sіnglе molеculеs and visulaising strucures have both become possible through the use of lіvеcеll supеr-rеsolutіon іmаgіng. rеtrogrаdе trаnsport, complеx morphologіcаl іntеrаctіons bеtwееn аdhеsіons and elongation have been shown by‘adhеsіon scаffold rе-modеllіng.’ direct characterisation of thе manner in which pаxіllіn molеculеs were transported іnto аnd away from аdhеsіon scаffolds has also become possible. such large-image-field films (of 28 µm × 28 µm) have been achieved over consecutive and repeated 25–60 sеcond-periods, аnd possess a 20nm precise sіnglе-molеculе locаlіsаtіon level (fig4), although the іmаgе possesses spаtіаl rеsolutіon of ∼60 nm. it is useful to remember at this point that ‘locаlіsаtіon prеcіsіon’ іs thе аccurаcy employed for identifying thе a point’s cеntroіd, while ‘spаtіаl rеsolutіon’ can be dеcided using a fеаturе’s size which is rеsolvable gіvеn thе numbеr of molеculеs which were possible to locаlіsе withіn а specific region. due to the fact that the laws governing аccurаtе sаmplіng іn spаcе are applicable to time as well, the acquisition-rates regarding complеtе іmаgеs need to be sufficiently rapid (twіcе as rapid as the fastest event) for the purposes of cаpturing thе target phеnomеnа and, at the same time, keep sufficiently high level of molеculаr dеnsіty for structurаl rеsolutіon purposes. 4.dеndrіtеs’ computational functions withіn thе cеrеbrаl cortеx: when reacting to stіmulаtіon by thе nеurotrаnsmіttеr glutаmаtе in brain slices, 20 mіcromеtеr long sеgmеnts of іndіvіduаl dеndrіtеs have the ability to create voltаgе discharges known as ‘nmda spіkеs’ or ‘plаtеаus’. occurences like these will possess voltаic аnd glutаmаtе ‘ceilings.’ it is therefore possible for іndіvіduаl dendrite sections to bе the same computаtіonаlly as dеcіsіon-mаkіng ‘unіts’ found іn nеurаl nеtwork modеls. due to the interaction between different sections, it is possible for a single dendrite to possess complicated аnd highly varied computаtіng powers, conditional on thе most up-to-date sequence of аctіvіty inside thе proximate nеuron nеtwork. it is possible that nmda spіkе/plаtеаus might give dеndrіtеs the chance to contrіbutе to ‘grаdеd pеrsіstеnt fіrіng,’ which is a process that scientists believe lies berneath workіng mеmory. further to this, they might give іndіvіduаl dеndrіtеs the power of orientation-selection as well as providing a ‘decoding’ ability for data which has been еncodеd in the form of ‘spіkе tіmеs’ over a series of аxons. a major research goal іs finding out if dеndrіtіc nmda spіkе/plаtеаus are important to thе іntаct brаіn durіng normаl functіon. this can be achieved through dendrite-observation іn-vіvo in order to monitor any bigger cаlcіum-trаnsіеnts connected to nmda spіkеs and plаtеаus. al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 125 moreover, some leading scientists have undertaken investigations into іntеrаctіons with nmda spіkеs and plаtеаus in numerous dеndrіte areas at the moment, by employing pаttеrnеd dual-photonic glutаmаtе-uncаgіng withіn brаіn segments. a locаlalised dеndrіtіc spіkе/plаtеаu potеntіаl аnd cаlcіum trаnsіеnt can be caused by focаl-іontophorеsіs for brіеf glutаmаtе-pulsеs on individual-cortіcаl pyrаmіdаl-nеuron bаsаldеndrіtеs. 4.1 data encoding within the cеrеbrаl cortеx? the majority of somаto-sеnsory nеurons discharge only 1/2 аctіon potеntіаls within a period of shorttime sеnse stіmulation like a ‘whіskеr dеflеctіon.’ therefore, data regarding thе stіmulating factor (like position or orientation) could be еncodеd via rеlаtіvе-аctіon potеntіаl-tіmіng over wide ranges of nеuron-types [7]. cаlcіum trаnsіеnts are a means of monitoring action potentials in neurons. action potеntіаls will most often be connected to cаlcіum trаnsіеnts within the call's body as well as proxіmаl-dеndrіtеs possessing fast-onsеt simultaneous with аctіon potеntіаl. the above makes it possible to determine the an аctіon potеntіаl up to an accuracy of just several mіllіsеconds, in the case of an іmаgіng tеchnіquеwith enough speed being usеd. it is possible to loаd cаlcіum-sеnsіng fluorеscеnt dyеs into mаny nеurons аt oncе. as an alternative to this, there are now strаіns of gеnеtіcаlly modіfіеd mіcе that еxprеss аrtіfіcіаl fluorеscеnt protеіns that can sense calcium withіn a neuronal sub-sеt. currently, attempts are being made to bring together thеsе methods wіth fast dual-photonic visualising for thе cеrеbrаl cortеx іnvіvo. this is for the purposes of gauging rеlаtіvе-аctіon potеntіаl tіmings over sections tens-hundrеds of nеurons-wide at times of stimulus to the sense. 5. conclusіon there іs not а constraining bаrrіеr anymore to the potential for achievement іn lіght microscopy. this is due to the circumventing of the dіffrаctіon lіmіt that was іmposеd by standard light microscopy. it is possible to visualise molecular structures аt thе right sіzе, аnd rеsolutіon levels sіmіlаr to еlеctron tomogrаphy have the capability of being achieved with thе benefit of vеry hіgh copy numbеr, molecularly -spеcіfіc lаbеllіng. despite this, challenges remain for the application of these new technologies. it is still necessary to attempt a balance bеtwееn fast аcquіsіtіon and іmаgе resolution quality. prеcіsе molеculаr locаlіzаtіon sometimes does not lead to аdеquаtе structurе resolution. it is possible that living cells can move molеculеs fаstеr thаn they can currently be imaged . due to the fact that thе currеnt colour pаllеt іs constrained, thеrе іs a constant requirement for morе probеs – this may slow down the rate аt whіch supеr-rеsolutіon іs аdoptеd іn the bіological sciences. what is more, placing supеr-rеsolutіon іmаgеs іn contеxt is going to be vital. as such, lіght or еlеctron mіcroscopy have the ability to give us a useful bаckground for іntеrprеtіng thе nеw lеvеl of ultrаstructurе wе can see. lastly, there is amazing potential for the biological sciences in supеrrеsolutіon mіcroscop. supеr-rеsolutіon can give crеаtіvе scіеntіsts the means to attain new lеvеls of undеrstаndіng regarding the molecular mechanisms involved in nanosensing. rеfеrеncеs: [1] westphal v, rizzoli so, lauterbach ma, kamin d, jahn r, hell sw. 2008. video-rate far-field optical nanoscopy dissects synaptic vesicle movement. science, 320: 246–249. [2] betzig e, patterson gh, sougrat r, lindwasser ow. 2006. imaging intracellular fluorescent proteins at nanometer resolution. science, 313: 1642–1645. al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 126 [3] harke b, ullal ck, keller j, hell sw. 2008. three-dimensional nanoscopy of colloidal crystals. nano lett, 8: 1309–1313. [4] hein b, willig ki, wurm ca, westphal v, jakobs s, hell sw. 2010. stimulated emission depletion nanoscopy of living cells using snap-tag fusion proteins.biophys j, 98:158–163. [5] micheva kd, smith sj. 2007. array tomography: a new tool for imaging the molecular architecture and ultrastructure of neural circuits. neuron, 55:25–36. [6] rayleigh l. 2006. on the theory of optical images, with special reference to the microscope.philos mag, xlii:28. [7] shtengel g, galbraith ja, galbraith cg. 2009. interferometric fluorescent super-resolution microscopy resolves 3d cellular ultrastructure. procnatlacadsci u s a, 106:3125–3130. figure(1): simplified jablonski diagram: sourcе: hаrkе, 2008, 1309[3] figure (2): (a) point spread function (psf) and sted resolution (b) specimen +illumination pattern = structured illumination (c) analysis for single plam image: sourcе: bеtzіg, 2006, 1645[2] al-qadisiya journal for engineering sciences, vol. 8……no. 2 ….2015 127 figure (3): use colour for dеtеct multіplе spеcіеs: source: mіchеvа,2007, 30[5] figure (4): mеаsurіng dynаmіc procеssеs wіth supеr-rеsolutіon tеchnologіеs: sourcе: shtеngеl, 2009, 3125[6] template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 10 -qadisiyah journal for engineering sciences . all rights reserved. utilizing a permanent-magnet alternator with the full converter in wind turbine increases the efficiency of supplying an active and reactive power to the electrical network muhammad al badri department of chemical engineering, university of al-qadisiyah, iraq. malbadrikut@gmail.com, eng.mohammed.abdalrodhal@qu.edu.iq received on 20 december 2017 accepted on 22 january 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.517 abstract: the alternator depends entirely on the conversion of kinetic energy into electrical energy by the presence of a magnetic factor. wind energy is defined as the process of converting wind energy into another form of energy that is easy to use. in this paper, a permanent-magnet-alternator (pma) with full-converter (fc) was used in the wind turbine (wt) generator instead of the excitation coil of the magnetic field. this method was used to save lost energy in the induction coil. a complete wind turbine model with a (fc) was connected to a generator with a fixed magnetic field and an electric grid was fed. this simulation system was completed by psim simulation program. in this work, the ip control system was used to operate the simulation system. in this study, a greater stable amount of real and reactive power was obtained from the wind turbine. keywords: wind energy, wind turbine (wt), permanent-magnet alternator (pma) and full-converter (fc). introduction today, the most important characteristics of the electric power system are being composed of ac threephase systems run at a constant voltage, synchronous machines (generators) operate at constant frequency and power transmits for long distances. in addition, all electric power systems with a variety of ac and dc systems are predicted to be integrated into all three stages: generation, transmission and the distribution. these power systems should also be able to handle all types of synchronous and asynchronous generators, centralized and decentralized resources (distributed) [1]. these networks still need various sources of energy in order to support them due to the incredible demand for power. therefore, the main goal of power mailto:eng.mohammed.abdalrodhal@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 11 -qadisiyah journal for engineering sciences . all rights reserved. generation engineers is to find more abundant, cheap and environmentally friendly sources. according to the energy law, this stipulates that the energy is not depleted and is not created, but turns from one form to another. there are many forms of energy such as kinetic energy, thermal energy, mechanical energy, nuclear energy, chemical energy and others [1], [2]. this energy can be converted from one form to another by using different devices such as electricity which is the mainstay of life. electricity is obtained from converting several energy sources like fossil fuels-petroleum, which is created by the pressuring and heating of the living organisms. in fact, these sources are harmful to the environment because they produce toxic gases when burned, and are not available in all regions of the world. currently, in most countries, wind power is increasing in demand for electric power production and is rapidly being planned for interconnection. it is expected to continue in this direction (i.e. the use of wind energy to produce electricity) for several reasons; including increasing concerns about the pollution of the environment and the warming of the globe, keep energy production safe, and provide jobs. there are a large number of advanced technologies to manufacture different types of wind turbines, which in turn compete for a larger share in the market for this booming industry [3]. as is generally known, the basic principle of the energy that is generated in the generator by spinning the rotor inside the stator where the electric magnetic field is there. the magnetic field for excitation is created by a low current (about 4 amps).this means; there is a dissipated energy (around 30 watts) in the coil due to this current [2]. the basic idea of this research is to solve this issue by using a permanent magnet instead of the coils in the alternator of the “full-converter” wind-turbine. the energized coils were replaced by a permanent magnet to produce constant magnetic and a special design uses for the stator in order to be able to increase the voltage when the rotation of the turbine is low (in case of the slow wind). the generated voltage of the wind driven, self – excited induction generator (seig) is mainly depending on the wind velocity fluctuations and load variations. by choosing, the proper value of the self-excitation capacitor banks achieves the reactive power requirements [3]. a combination of series and parallel capacitors are used to excite the induction generator while operating at variable speeds [4]. the (pm) has a flux that measures in "kwb for turns" [1]. each per-unit of a magnetic-strength produces a voltage at the terminal within the rated-range. this will happen during the rotating of the machine at normal speed and under "no-load" condition. in addition, this type of alternator is very appropriate to use in hydro power plants (high-speed turbines) [5], [6]. in other words, in order to maintain the amount of output power at maximum and not allow any amount of power to be dissipated. the advantages of this technology are actually as follow:  to improve the power quality of the network  to separate the generator from the network when a fault occurs and  to allow the wind turbines to work with a vast range of wind speeds. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 12 -qadisiyah journal for engineering sciences . all rights reserved. in addition, this topology needs a convertor, which is capable of carrying the entire output of the generator [7]. as a final output, wind energy extraction will be improved. this type is very expensive, but it provides a high amount of active-power and reactive-power to the network. in this research, a system of integrated wind turbine containing a control circuit, a magnetic generator and a (fc) to connect the turbine to the grid was simulated. this application was achieved by psim program. all results and curves were measured and plotted respectively by using the same simulation program. 1. technology’s classifications for wind turbine wind turbine technologies are amazingly developed and used in large numbers today. as well as most of the wind, power plants made up of large numbers of turbines are usually located in groups called wind farm, often using the same technology. to summarize these different technologies, consideration must be given to the cost, complexity of manufacturing, the type of equipment used for this process and, most importantly, the efficiency of extracting a large amount of energy from the wind. modern wind turbines often consist of a rotary part and blades connected to it to extract kinetic energy from the wind, the gearbox is used to increase the speed transferred from the rotor to the generator to be sufficient to rotate at its specified speed, and a generator to generate electricity. as a result, changing the speed of the wind continuously needs the generators that are inherently synchronous. thus, synchronous-induction generators are used in the most typical wind turbines. also, electronic converters are used in order to control the both parts of the power output (real and reactive) of the wind turbine [8]. in general, wind turbine technologies can be categorized into four main types: a) (wts) with fixed-speed (fs) b) (wts) with variable-slip (vs) c) (wts) with doubly-fed induction generator (dfig) d) (wts) with (fc). figure 1 shows all the above types of (wt) technologies. the most use for (wts) are the fixed speed type figure 1-a. they work with a little bit change in the speed of their rotor and they use the squirrel-cage type of the induction machines which are usually directly connected to the network. most of these turbines are not capable to control the pitching of the blades. despite being fairly strong and reliable, this technology has a huge disadvantage, vis that the extraction of energy from the wind is below the required level and therefore it needs the compensation for the reactivepower. variable speed wind turbines are designed in figure 1-b to operate the rotary with an extensive range of speed. usually these turbines use blades-monument in their work. for this reason, these turbines capture more wind energy than fixed-speed turbines. the resistance of the dynamic of the rotor or the variability of the slipping in the turbine is to control and to increase the range of the speed of operation and that can al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 13 -qadisiyah journal for engineering sciences . all rights reserved. cause a dissipated power in the rotor. the losing power in the slipping could be repaired by employing the (dfig) fig. 1-c and the back-to-back (ac/dc/ac) converter to the rotor circuit of the turbines [8]. the rotor current is controlled by the "flux vector" that can allow to decouple the output of the real power and reactive power. in addition, this can increase the extraction amount of energy from the wind and can reduce the stresses on the mechanical parts. as a result, the converter cannot operate at full capacity because the converter manages the power just in the rotary circuit. commonly, the flow of the power in turbines with full converter figure 1-d, a back-to-back (ac/dc/ac) converter, is one path to the grid. in addition, it is impossible to connect these turbine types directly to the network. in addition, they use either synchronous or inductive type of generators to offer an independent control to the real power and reactive-power. in this paper, another synchronous generator replaced the synchronous generator in the last type (full-converter) of the turbine, but it contains a permanent magnet for the “excitation field” instead of coils [8]. figure1. wind turbine technologies [6] al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 14 -qadisiyah journal for engineering sciences . all rights reserved. 2.the implemented model in psim figure 2 shows the full model of the (wt) that simulated by “psim” program, without the diversified control blocks, after each individual sub-system were compiled. based on that, in order to simplify the simulations in this work, the systems of conversion and control will be explained separately from the rest of the system. therefore, the fullconvertor permanent magnet alternator (pma) wind turbine consists of the following sub-systems: tables below (1, 2 and 3) show the characteristics of both the turbine and the alternator in (psim) program that used in this simulation. figure 2 the simulated model without the control circuits table 1: characteristics of the turbine made of the turbine enircen e84 3mw diameter of the rotor 80 m height of the hub 76 m number of the blades (3) (cut-in) speed of the wind (5 m/s) (cut-out) speed of the wind (27 m/s) speed rate of the wind (6 m/s) (17 m/s under used) speed of the rotor (4/20 rpm) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 15 -qadisiyah journal for engineering sciences . all rights reserved. table 2: rates of the pma mva ratio (3 mva) ratio of the voltage (4.6 kv l-l) ratio of the frequency (50 hz) table 3: parameters of the pma r-winding of the stator 0.018 pu xleakage of the stator 0.058 pu unsaturation of the x for the (d-axis) 0.49 pu unsaturation of the r for the (q-axis) 1.09 pu r-of the d-axis of the damper winding 0.63 pu xof the d-axis of the damper winding 0.179 pu rof the q-axis of the damper winding 1.09 pu xof the q-axis of the damper winding 1.182 pu intensity of the magnetic 4.9 pu converter: the duties of the rectifier and buck/boost converter in the models are to convert the ac output of the pma to a constant dc voltage. a three-phase diode-bridge uses to convert the output of the pma to a changeable dc-voltage. the maintaining of the dc-voltage level to be constant at 3.6 kv is the duty of buckboost converter. there is a link of a dc capacitor, a ground between two identical capacitors, due to the issues grounding of the reference of the psim, which are indicated in figure 3. figure 3: converter-circuit of rectifier and buck/boost. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 16 -qadisiyah journal for engineering sciences . all rights reserved. a proportional–integral (pi) control: the main idea of the controller depends on pi-control. this means that the output of the controller is directly proportional to the error of the signal. for this work, the duty-signal that runs the pi produces when there is an error between the required voltage, which sets at (3.6 kv), and the real voltage which drives the pi-controller. then, duty-signal compares with a square wave signal in order to send signals of firing to switch the insulated gate bipolar transistor (igbt) in the buck/boost converter on or off as cleared in figure 4. figure 4: the pi controller. inverter: figure 5 shows an implemented current controlled of the voltage-source inverter (vsi). this inverter should be able to separate the control of the real and reactive power, since the design of the controller for the inverter depends on the theory of the flux-vector. two controllers are independent pi, for comparing the "reference-signals" of the values of real, and the error, as indicated in the figure 5. the error of the real power drives the (iq) signal, whereas the error of the reactive-power drives the (id) signal. the domain values of dq0 are transformed to the reference (iabc values) as cleared in figure 5 (take into consideration the angle-signal this is calculated from the voltage-phasor. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 17 -qadisiyah journal for engineering sciences . all rights reserved. figure 5: real-power and reactive-power errors drive q and d controllers of current respectively for the control system, the switching of the igbts happened by the comparison between (ibec) currents of the reference and with both of the real currents. figure 6 shows the final stage of the controller of the real power and reactive power of the model due to the switching of the igbts of the inverter on. figure 6: switching-igbts controls p and q 3. results and discussion in order to verify if the independent control of the real power and reactive power is established or no, four tests performed on the simulated model: reduced real-power, reduced reactive-energy, increased real power and increased reactive-power. these models were changed individually a step-by-step, i.e., at a given moment, the change of the step was done by either the speed of the wind or the demand for reactive-energy. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 18 -qadisiyah journal for engineering sciences . all rights reserved. first test, the simulation was run by reducing the real power. the change to the speed of the wind was from 12 m/s to 10 m/s at t =11s. the demand for reactive-power was fixed at 0.6 mvar. figure 7 shows that the real power-output reduces and stabilizes to the new amount. reactive-power reduces at first, but improves to the main value. fig. 7: real-power-reduced ” second test, the simulation was run by reducing the reactive-power. figure 8 shows that the speed of the wind stays at 12 m/s during the run, but the demand for reactive-power was varied from (0.5 mvar to 0.2 mva r) at t =11s. the reactive-power reduced, as predicted. the output of the real power indicates a little disturbance, but improves to the real value. figure 8: reactive-power-reduced third test, the simulation was run by increasing the real power. the speed of the wind was varied from 10 m/s to 14 m/s at t = 11s. the demand for the reactive-power was fixed at 0.6 mvar. figure 9 shows that the output of the real-power increases and stabilizes to the new amount. reactive-power increases at first and improves to the main value. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 19 -qadisiyah journal for engineering sciences . all rights reserved. fig. 9: real-power-increased ” forth test, the simulation was run by increasing the reactive-power. figure 10 shows that the speed of the wind stays at 11m/s during the run, but the demand for the reactivepower was varied from (0.5 mvar to 0.7 mvar) at t =11s. the reactive-power increases, as predicted. the output of the real power once again shows a little disturbing, but improves to the main value. figure 10: reactive power increased in fact, the results of this research compared with the results of research no. 6 and 7 were more reasonable and within the applicable limits. most of the researches on this subject are use capacitors to compensate the dissipated energy as a result of starting the induction generator of the wind turbine to take off. conclusions and future work usually, in wind turbine the number of poles is low in order to increase the speed of the shaft and for this reason the gearbox is used. thus, any torque applied to the shaft starts to rotate the shaft, which means al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 20 -qadisiyah journal for engineering sciences . all rights reserved. energy transferred go and forth from the turbine to the grid during the change in the load. in other words, an oscillating in a torsional-mode will happen and if there is no way to protect the shaft, it may be damaged. finally, the research approved the possibility of using a (pma) with (fc) in (wt) to raise the amount of energy that transferred from wind turbines to the electrical grid, taking into account the change in wind speed. also, the results approved that after applying the different quantities of wind speeds in table 4 to the module, the maximum turbine output at maximum speed can be sustained and stable as cleared from the curve of the power in figure 11. in addition, we note from the same curve of power that the edge of the curve before the turbine reaches its specified speed is smooth and this is required to produce a stable capacity without creating an operating disturbance. table 4: wind speeds and power output for the simulated model wind speed (m/s) power out (mw) 4 0.21 5 0.34 6 0.47 7 0.65 8 0.87 9 1.23 10 1.50 11 1.85 12 2.0 13 2.0 14 2.0 15 2.0 16 2.0 17 2.0 18 2.0 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 21 -qadisiyah journal for engineering sciences . all rights reserved. figure 11: power curve for simulated model this research suggests that it is possible to increase the amount of energy produced by wind turbines when considering the design of their electric generator. references 1. gus wright, “fundamentals of medium/heavy duty diesel engines”, jones & bartlett publishers, 2015. 2. reed, stanley, "as wind power sector grows, turbine makers feel the squeeze" (november 2017). 3. swati devabhaktuni, “different self excitation techniques for slip ring self excited induction generator “, volume 38, no.2, january 2012. 4. t.r. ayodele, b.b. adetokun, “optimal capacitance selection for a wind-driven self-excited reluctance generator under varying wind speed and load conditions”, applied energy, volume 190, 15 march 2017. 5. mahinsasa narayana, keith m. sunderland, ghanim putrus, michael f. conlon “adaptive linear prediction for optimal control of wind turbines” renewable energy, volume 113, december 2017 6. a. honrubia-escribano, e. gómez-lázaro, j. fortmann, p. sørensen, s. martin-martinez, “generic dynamic wind turbine models for power system stability analysis: a comprehensive review” renewable and sustainable energy reviews, 2018. 7. yuan yuan, jiong tang, “on advanced control methods toward power capture and load mitigation in wind turbines” engineering, volume 3, issue 4, august 2017. 8. staffell, iain; pfenninger, stefan. "using a bias-corrected reanalysis to simulate current and future wind power output". energy. 08. 68 (2016). template for academica science journal journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 270 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. performance evaluation of single carrier frequency domain equilizer (sc-fde) over impulsive noise channel hussein abdullah leftah, h.a.leftah@stu.edu.iq southern technical university, basrah technical engineering college, electrical engineering, basrah, iraq. husham lateef swadi, hisham.romi@uobasrah.edu.iq basrah university, college of engineering, electrical engineering , basrah, iraq. abstract: impulsive noise is considered as one of the major source of disturbance in the state-of-the-art multicarrier (mc) communication systems. therefore, several techniques are being constantly proposed to eliminate the effect of such noise. in this work, a time domain matrix interleaved is compiled with a single carrier frequency domain equalizer (sc-fde) is proposed to reduce the deleterious effects of impulsive noise. a mathematical model for the proposed scheme is also presented in this paper. simulation results show that the proposed technique superiors the interleaved multicarrier system where the proposed scheme can completely avoid the error floors not only at high signal-to-noise ratio (snr) but also at heavily distributed impulsive noise. the bit-error-rate (ber) of the alternative proposed scheme decreases as the signal-to-noise ratio (snr) increases whereas the ber of the standard system suffers from error-floors with a constant ber at about 10-3 for about 8 db snr for medium and heavily impulsive noise. keywords: multicarrier (mc), single carrierfrequency domain equalization (sc-fde), impulsive noise (in), channel modelling, interleave. introduction single carrier-frequency domain equalizer (sc-fde) is a technique that has a noticeable attention among other wireless modulation schemes in the last ten years. the sc-fde system has compiled the popular attributes of both single carrier systems and multicarrier systems. as a single carrier, the sc-fde has low peak-to-average power ratio (papr), not sensitive to amplifier nonlinearity, tolerance to carrier frequency offset sensitivity. on the other hand, in comparison to multicarrier modulation, the sc-fde system is robust to multipath fading channels, efficient to intersymbol interference (isi) mitigation [1] and it has simple equalization. thus it has been taken up in several wireless applications such as long-term evolution (lte), ultra-wide band (uwb), ieee 802.11 and hiperlan/2. in the higher frequencies, additional attention will be recruited and highly frequency selective called impulsive noise, hence that the transmitted data may be damaged by impulsive noise in addition to the other noise like the colored gaussian noise and narrowband interference [2]. modelling of electromagnetic interference (emi) can be separated into two approaches, physical modelling and statistical-physical modelling. the statisticalphysical examples are chosen because they are more accurate models than the physical models due to the mix between natural and human-made sources [3]. noise generally limited the channel capacity where the system performance be downgraded. one of the most important character of noise is that affected by the new modulation schemes is impulsive noise. impulsive noise can be defined as relatively short duration “on/off” switching noise pulses, generated from a different of sources the sources of impulsive noise are generated for journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 271 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. all cases of trading operations in electrical devices [4]. the other source of impulsive noise came from the modelling of interferences between the adjacent channels in mobile communication [5]. asynchronous impulsive noise levels can reach 50db more than thermal noise so that this value causes a degradation in communication system performance [6,7]. thus, the communication system should be designed carefully to cope with the impulsive noise. this paper, proposes sc-fde modulation technique for applications over impulsive noise channel such as digital audio broadcasting (dab), digital video broadcasting (dvb) and power line communications (plc). also suggests an efficient interleaving technique to further reduction in the effects of the impulsive noise. to clarify the contribution of this theme, it is listed in four points equally  propose the sc-fde modulation for applications with impulsive noise effects instead of the multicarrier digital modulation systems.  presents an analytical, mathematical model for the proposed scheme in the presence of impulsive noise.  matrix-interleaved time domain sc-fde is also investigated in this paper as a solution to severe impulsive noise channel applications.  monte carlo computer simulations are implemented to establish the efficacy of the proposed sc-fde technique over the conventional multicarrier modulation technique. 1. impulsive noise model and effect a definition is required to identify an impulsive noise from colored (background) noise,when measuring impulse noise.there is a certain level (threshold) is identified, and any variation exceeds this threshold level is called impulsive noise. typical impulsive noise time period is from a few microseconds to milliseconds. within this paper,the middelston’s additive white class a noise (awcn) model is used as a statistical model for the impulse noise [8]. this model provides both the colored and impulse noise. where the received sample rk at time instant k is represented by 𝑟𝑘 = 𝑠𝑘 + 𝑤𝑘 + 𝜉𝑘 𝑟𝑘 = 𝑠𝑘 + 𝑖𝑘 where sk is the transmitted sample, 𝜉𝑘 and wk are the complex impulse and gaussian colored noise samples, and 𝑖𝑘 stands for the complex channel noise sample that collects the impulse noise and colored noise samples. a two states impulse noise model can be applied for modelling awcn channel where the colored and impulse noise is picked up with the probability distribution function ik is given by 𝑝(𝑖𝑘 ) = (1 − 𝑐) 1 2𝜋𝜎0 2 𝑒 (− |𝑖𝑘| 2 2𝜎0 2) + 𝑐 1 2𝜋𝜎1 2 𝑒 (− |𝑖𝑘| 2 2𝜎1 2) , 𝜎0 2 = 𝜎𝑤 2, 𝜎1 2 = 𝜎𝜉 2 𝐴 + 𝜎𝑤 2 where c is the impulse noise index and is given by the multiplication of the average count of impulses per unit time and the average duration of the emmitted impulses enering the receiver [9]-[11]. in other words c is the probability of appearance of impulsive noise, a is the lowest value of interest and b is the highest value of interest. the probability density function (pdf) of impulsive noise is written as 𝑓(𝑥) = 𝑐 𝑏 − 𝑎 + (1 − 𝑐)𝛿(𝑥) in this paper in order to test the propoesed sc-fde system over different types of impulsive noise distribution and conditions, the following parameters are set to be as: a=-10, b=10 and three types of impulsive noise levels (weak, medium and high) c=0.001, c=0.003 and c=0.006 respectively. it is worth to mention here that (1) (2) (3) (4) journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 272 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. the system performance will be changed as these values of c changed, however, the chosen values are the most practical and real case. as the impulsive noise power is much more eminent than the average power of the thermal noise, the use of fft in multicarrier modulation will average this high noise power among the all subcarriers spectrums which lead to whole system performance degradation. consequently, a sc-fde system is purported in this paper with effective interleaving technique to mitigate the ramifications effect of such interference on the system operation. 2. sc-fde system with the impulsive noise channel consider the sc-fde system mode [12], which is shown in figure 1. the input data are first mapped into a specific constellation and the ith time domain block of n-points incoming modulated data vector, which is chosen uniformly from qam or psk constellations. finally, the input data is passing through a mapper to produce a digitally encoded symbols. in the paperwork, we will use bpsk phase shift keying and qam. these mapped symbols are found in vectors, each of n symbols. it follows that, a cyclic prefix of length m=n/4 is added to each transmit symbol to make the vector this signal is then given through the plc channel with multipath effect, additive white gaussian noise (awgn) and driving noise 𝑤𝑘 (awgn) and impulsive noise (𝜉𝑛). the received signal is then written as 𝑥𝑛 𝑤ℎ𝑒𝑟𝑒 𝑛 = 0,1, … … . . (𝑁 + 𝑀 − 1) 𝑦𝑛 = 𝑥𝑛 ∗ 𝑔𝑛 + 𝑤𝑛 + 𝜉𝑛 where, 𝑔𝑛 is the channel impulse response, 𝑤𝑛 is the awgn and 𝜉𝑛 is the impulsive noise. figure 1. standard matrix-interleaved multicarrier (mi-mc) system block diagram. (5) journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 273 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 2. proposed matrix-interleaved sc-fde system block diagram. on the receiver side, the cyclic prefix is first removed to cancel the effect of inter-symbol interference (isi). under the assumption of perfect frequency 𝑟 = 𝐹𝑌 where 𝐹 is the discrete fourier transform matrix and 𝑌 = [ 𝑦1 𝑦2 𝑦3 … … . . 𝑦𝑛−1] 𝑇 thus, 𝑟𝑛 = 𝑆𝑛. 𝐺𝑛 + 𝑤𝑛. 𝜉𝑛 where 𝑆𝑛 = ∑ 𝑦𝑚𝑒 −𝑗2𝜋𝑚𝑛 𝑁𝑁−1 𝑚=1 , is the fourier transform of 𝑦𝑛 , 𝐺𝑛 is channel transfer function , 𝑤𝑛 and 𝜉𝑛 is fourier transform of awgn and impulsive noise respectively. frequency domain zero forcing single tap equalizer is then performed to remove the effect of the channel 𝑟𝑛 𝑍𝐹 = 𝑆𝑛 + 𝑤𝑛 𝐺𝑛 + 𝜉𝑛 𝐺𝑛 inverse dft is then applied on (8) to produce �̂�𝑛 = 𝑥𝑛 + ∑ 𝑤𝑚 𝐺𝑚 𝑒 𝑗2𝜋𝑚𝑛 𝑁 𝑁 𝑚=0 + ∑ 𝜉𝑛 𝐺𝑛 𝑒 𝑗2𝜋𝑚𝑛 𝑁 𝑁 𝑚=0 (6) (7) (8) (9) journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 274 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2.1. performance analysis of sc-fde the total error signal is the difference between transmitted and receive signal 𝑒 = ( 𝑥𝑛 − �̂�𝑛) then, 𝑒 = ∑ 𝑤𝑚 𝐺𝑚 𝑒 𝑗2𝜋𝑚𝑛 𝑁𝑁 𝑚=0 + ∑ 𝜉𝑛 𝐺𝑛 𝑒 𝑗2𝜋𝑚𝑛 𝑁𝑁 𝑚=0 the signal –to-noise ratio (snr) is 𝑆𝑁𝑅 = 𝑆𝑖𝑔𝑛𝑎𝑙 𝑝𝑜𝑤𝑒𝑟 𝑁𝑜𝑖𝑠𝑒 𝑝𝑜𝑤𝑒𝑟 = 𝐸[𝑥𝑛. 𝑥𝑛 ∗ ] 𝐸[𝑒. 𝑒∗] = 𝛿𝑆 2 𝛿𝑛 2 ∑ 1 |𝐺𝑚| 2 + 𝛿𝜁 2 ∑ 1 |𝐺𝑚| 2 𝑁−1 𝑚=0 𝑁−1 𝑚=0 = 𝛿𝑆 2 (𝛿𝑛 2 + 𝛿𝜁 2) ∑ 1 |𝐺𝑚| 2 𝑁−1 𝑚=0 where 𝛿𝑆 2 is the signal power, 𝛿𝑛 2 is the standard deviation of the awgn (awgn noise power), 𝛿𝜁 2 is the impulsive noise power. 2.2. numerical results to investigate the old and proposed systems under the awgn and impulsive noise, matlab (monte carlo) simulation is used to clear up the superiority of the time domain interleaved single carrier frequency domain equalizer (sc-fde) over the interleaved multicarrier system. number of subcarriers used in this simulation is 1024 with a 256 subcarriers are used as a guard interval to prevent the intersymbol interference (isi). the simulation is run for different impulsive noise level scenarios to certain the validity of our proposed scheme over the conventional system. the ber performance of the proposed sc-fde is introduced and compared with the conventional mc system over impulsive noise channel is shown in figures 1 and 2 for the qpsk and 16-qam modulation formats respectively. for fair comparison, time domain matrix interleaved is used in both proposed scheme and the classic mc system. it is clear from figure 1 that, for qpsk data mapping, the proposed matrix interleaved misc-fde is superior the standard mi-mc system for different levels of probability of appearance of impulsive noise c=0.001, c=0.003 and c=0.006. we take these three values of c (weak, medium and high) impulsive noise to validate the proposed scheme performance under different types of operating conditions. it is also clear that unlike the proposed mi-sc-fde system, the classic mi-mc system suffers from error floors for medium and high impulsive noise levels c=0.003 and c=0.006 at low signal-to-noise ratio (snr=8 db) whereas our proposed scheme ber still decreases rapidly as snr increases without any error floors for even medium and high impulsive noise levels. to further investigate the superiority of the proposed mi-sc-fde scheme over the standard mi-mc system, 16-qam data mapping is also taken into consideration and shown in figure 2. figure 2 shows the ber performance of the proposed mi-sc-fde and compared it with the ber performance of the standard mi-mc system for different levels of impulsive noise and 16-qam constellation. one can notice that the proposed scheme still better ber performance than the classic scheme. the classic mi-mc scheme still suffers from error floors at c=0.003 and c=0.006 at snr=13 db. however, the proposed mi-sc-fde scheme still robust to impulsive noise and error floors even for high snr and high impulsive noise levels. the superiority of the proposed scheme becomes more significant as the severity of impulsive noise increased. (10) journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 275 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 3. ber performance of the proposed mi-sc-fde and the standard mi-mc systems in the case of qpsk data mapping and over impulsive noise channel. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 276 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 4. ber performance of the proposed mi-sc-fde and the standard mi-mc systems in the case of 16qam data mapping and over impulsive noise channel. 2.3. conclusions a new time matrix interleaved sc-fde system is presented to cope with the severity of impulsive noise channels. simulation results proved the superiority of the proposed mi-sc-fde over the standard mimulticarrier system for different impulsive noise levels and data mapping. unlike the conventional mc system, the ber of the proposed system continues to decrease rapidly as the snr increases and does not suffer from any error floors. however, the conventional mi-mc system sufferes from error floors at low level of snr in the case of medium and high impulsive noise. the proposed mi-sc-fde has proved itself as an efficient technique to eliminate the deleterious effects of impulsive noise and achieved good ber performance in comparison to the standard mi-multicarrier system. . references 1. fabricio, p.; giorgio,m.v.; reza, k.; naofal. a; morat, u.; hakam, m.single., carrier frequency domain equalization,” ieee signal processing magazine”. sept. 2008. 2. thokozani, s.; han vinck, a.j; hendrik, c. f., a study on implusive noise and its models,” the 4th world conference on educational sciences”, wces-2012, barcelona, spain, 2-5 february 2012, pg. 128-132. 3. f. rouissi, h. gassara, a. ghazel and s. najjar, comparative study of impulse noise models in the narrow band indoor plc environment,” tenthe workshop on power line communications”, , 10-11 october, 2016, paris, france. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 277 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 4. kapil gulati, aditya chopra, brian l. evans and keith r. tinsley., statistical modeling of co-channel interference,” acoustics speech and signal processing (icassp)” 2010 ieee international conference on 14-19 march 2010 dallas, tx, usa. 5. marcel nassar, kapil gulati, yousof mortazavi and brian l. evans., statistical modeling of asynchronous impulsive noise in powerline communication networks,” global telecommunications conference (globecom 2011)” 2011 ieee, 5-9 dec. 2011, kathmandu, nepal. 6. namrata jain, namrata sahayam, iterative looping for impulsive noise channels in qam-ofdm based systems” international journal of emerging technology and advanced engineering” vol. 3, issue 11, november 2013 . 7. amit grover and **amit kumar kohli, simulation pf implusive noise environment for othogonal frequency division multiplexing wireless systems,” international journal of computing & business research” issn (online): 2229-6166. 8. vinay chakravarthi gogineni1, subrahmanyam mula., proportionate adaptive filtering under correntropy criterion in impulsive noise environments,” arxiv:1707.00315v1 [cs.sy] 2 jul 2017. 9. alexey ruchay and vitaly kober., impulsive noise removal from color images with morphological filtering,” the 6th international conference on analysis of images, social networks, and texts” (aist 2017), 27-29 july, 2017, moscow, russia. 10. jihad fahs, ibrahim abou-faycal., information measures, inequalities and performance bounds for parameter estimation in impulsive noise environments.” arxiv:1609.00832 . 11. marcel nassar, philip schniter, and brian l. evans., a factor graph approach to joint ofdm channel estimation and decoding in impulsive noise environments,” ieee transactions on signal processing,” arxiv:1306.1851. 12. a. al-dweik1 3, a. hazmi2, b. sharif3 and c. tsimenidis3 , effecient interleaving techniques for ofdm system over impulsive noise channels,” 2010 ieee 21st international symposium on personal indoor and mobile radio communications. http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=5487364 http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=6132211 http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=6132211 https://arxiv.org/abs/1609.00832 https://arxiv.org/abs/1306.1851 template for academica science journal journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 165 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. broadband microstrip antenna for 2g/3g/4g mobile base station applications wafaa mohammed hashim, college of engineering, al-mustansiryah university, baghdad, iraq, electrical engineering department, email: wafaa9896a@gmail.com asst. prof. dr. adheed hasan sallomi, college of engineering, al-mustansiryah university, baghdad, iraq, electrical engineering department, email: adalameed@yahoo.com abstract: — in this work, a staircase patch microstrip antenna with slots is proposed to cover the 2g/3g/4g cellular mobile base station bands, when the antenna is excited with a transmission line, creates several modes these modes are composite to obtain a large bandwidth. the proposed antenna operates in the band from 0.86 ghz to 4.78 ghz with an impedance bandwidth of 138%. the use of staircase patch antenna is to achieve more attractive performance such as wider bandwidth, better impedance matching and better radiation. inserting different slots to the patch of the antenna to enhance the gain and return loss. the gain is obtained ranging from 2.18 dbi to 5.3 dbi. good radiation efficiencies ranging from 70% to 97% is achieved. keywords: 2g/3g/4g mobile base station; broadband microstrip patch antenna; staircase patch; return loss; voltage standing wave ratio. introduction the fast growth of mobile communication systems needs both low cost and broadband antenna for base station [1]. microstrip patch antenna is utilized for its simplicity, low profile, inexpensive to fabricate using modernistic printed circuit technology, conformable to planar and non-planar surfaces. when mounted on rigid surfaces compatible with mmic (monolithic microwave integrated circiut) designs became mechanically robust [2]. main operational abuse of the microstrip antennas are contain low power gain, low efficiency, high quality factor (sometimes in excess of 100), very narrow frequency bandwidth, spurious feed radiation and poor scan performance [3]. a patch antenna is made by excavation metal on one part of dielectric substrate while on the other opposite side there is a metal which constructe a ground plane [4]. there are a great number of forms of microstrip patch antennas, they were designed to match particular characteristics. some of the common kinds are rectangular, square, and circular patches [5]. different feeding mechanisms are used to feed the antenna such as coaxial, stripline, aperture coupling or proximity [6].the size of the microstrip patch antenna is inversely commensurate to the operating frequency of the antenna and the bandwidth of the microstrip patch antenna is directly commensurate to the substrate thickness and inversely commensurate to the square root of the dielectric constant of the substrate [7]. 1. staircase patch antenna design the structure of the proposed staircase patch antenna is shown in the figure (1). the antenna is printed on (fr-4) substrate of thickness h=1.542mm with relative permittivity εr=4.3, fed by a microstrip feed line. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 166 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. the performance of the antenna can be estimated over a sweep frequency range from 0 ghz to 5 ghz. the antenna dimensions are (120mm× 100mm× 1.542mm), and it operates at minimum frequency fmin=0.86 ghz and maximum frequency fmax=4.67 ghz, the center frequency is fo =2.75 ghz, λ0 (wavelength of the center frequency) equal to 180.01mm. dimensions of the patch are chosen as w=61.5mm represent 0.565λ0, l=46.5mm represent 0.258λ0.the widths of the stairs w1, w2 , w3 equal to 6.5mm, 6.5mm and 7.58mm respectively and their lengths h1, h2 equal to 2.5mm. figure 1. the structure of the proposed staircase patch microstrip antenna. 2. the effect of different antenna parameters on its performance initial parameters of the proposed antenna give lousy performance, so that changing the antenna parameters and choosing the best values can be done, to improve its performance. 2.1. the effect of ground plan length figure (2) shows the s-parameter as a function of frequency for different values of ground plane length (lg), and fixing other values at w=61.5mm, l=46.5mm, lf=62mm, wf =2.5mm, wg=100mm. from the figure it can be noticed that the curve has good bandwidth with the best return loss at lg=61mm. figure 2. simulation of s11 versus frequency for different values of lg. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 167 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 2.2. the effect of ground plan width figure (3) shows the s-parameter as a function of frequency for different values of ground plane width (wg), with fixing other parameter at w=61.5mm, l=46.5mm, lf=62mm, wf=2.5mm, lg=61mm. it can be seen the best value is wg=100mm, because minimum return loss and good bandwidth can be obtained at this value. figure 3. simulation of s11 versus frequency for different values of wg. 2.3. the effect of feeder width figure (4) presents s-parameter for different values of feeder width (wf), and fixing other parameters at w=61.5mm, l=46.5mm, lf=62mm, lg=61mm, wg=100mm. the optimum value is wf=3 because it gives minimum return loss at first resonance frequency and at second resonance frequency. first resonance frequency f=1.06 ghz has return loss equal to -39.45 db, second resonance frequency f=2.4 ghz has return loss equal to -32.625 db. figure 4. simulation of s11 versus frequency for different values of wf. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 168 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 2.4. the effect of feeder length figure (5) illustrates s-parameter of the proposed antenna by varying the length of the feeder (lf ), and fixing other values at wf=3mm, w=61.5mm, l=46.5mm, lg=61mm, wg =100mm. the optimum value of feeder lenght is lf=62.5mm, because it gives good impedance matching better than other values at same bandwidth. figure 5. simulation of s11 versus frequency for different values of lf. the parameters of the optimized staircase patch are shown in table 1. . table 1. optimal parameters of the staircase patch antenna. the performance of the microstrip patch antenna can be further improved, by inserting multiple slots with different shapes and dimensions on the patch, because a slot is easy way to realize the redistribution of surface currents. design procedure for inserting the slot is to choice the best position that has minimum current distribution along the patch, after that it can be used as the proper slot with initial parameters, by optimization process, it can be chosen to achieve the best values that enhance the antenna performance. figure (6) shows the proposed staircase patch antenna with slots and the dimensions of each slot in the patch. parameter value description ls 120mm substrate length ws 100mm substrate width lf 62.5mm feeder length wf 3mm feeder width lg 61mm ground plan length wg 100mm ground plan width w 61.5mm patch width l 46.5mm patch length d 8.66mm the horizontal distance that is cut from the patch journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 169 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 6. the proposed staircase patch antenna with slots. figure (7) shows the influence of slots on the return loss, it is observed that without the slot there exist two poorly matched resonances at 3.1ghz and 4.1ghz. introducing of multiple slots into the patch improve the input impedance matching, at 3.1ghz the return loss is improved from -16 db to -39 db and at 4.1 ghz is improved from -12 db to -16 db. figure 7. simulation of s11 versus frequency for the staircase patch with and without slots. the proposed staircase patch antenna with slots is fabricated. figure (8) shows the photograph of the fabricated antenna. figure 8. photograph of the fabricated staircase patch antenna, (a) front view, (b) back view. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 170 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3. characteristics of staircase patch antenna with slots 3.1. s-parameter the fabricated staircase patch antenna is tested by using vna (vector network analyzer). figure (9) shows the simulation and measurement s-parameter of the proposed antenna. acceptable result between the measurement and simulation can be obtained, except from 3.5 ghz to 3.88 ghz became out of the proposed band. the variation in the measured and the simulated response is primarily due to fabrication errors, soldering of sma connector or ambient environment which the measurement are carried out. figure 9. simulation and measurement of s-parameter for the staircase patch antenna with slots. . 3.2. voltage standing wave ratio (vswr) the antenna has smaller vswr which means it is matched to the transmission line and can be considered the best antenna. the minimum vswr is 1, vswr =1 means no power reflected from the antenna, for practical applications vswr less than or equal to 2 can be taken into account [8]. figure (10) shows vswr for different frequencies, it is clear that from the curve, the value of vswr is less than 2 at all frequencies of the band and the best vswr can be obtained at resonance frequencies, at f=1ghz vswr =1.03, at f= 2.4ghz vswr = 1.02 and at 3.1ghz vswr =1. figure 10. simulation of vswr versus frequency of staircase patch antenna with slots. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 171 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.3. antenna gain figure (11) shows the effect of slots on the gain of the antenna, inserting slots to the patch also enhanced the gain of the antenna over a wide range of the frequencies. from 0.86 to 2 ghz the gain didn't change, from 2 ghz to 4.2 ghz the gain improved significantly, but for frequency range from 4.3 ghz to 4.8 ghz the gain slightly decreased. figure 11. the gain of the staircase patch antenna with and without slots. 3.4. input impedance from figure (12), it can be observed that the relative impedance matching between the feed line and the antenna, and the real part of the impedance at resonance frequencies (1ghz, 2.4ghz, 3.1ghz) are (48.9ω, 47.5ω, 48.15ω) respectively, while imaginary part of the impedance at resonances frequencies are (5.3ω, -1.3 ω, -1.7ω) respectively. figure 12. real part and imaginary part of input impedance against frequencies for staircase patch antenna with slots journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 172 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.5. current distribution the current distribution of the proposed staircase patch antenna with slots can be seen in figure (13). figure (13) offers the concentration of current in the antenna at frequencies 1ghz, 2.4 ghz, 3.1ghz and 4 ghz. figure (13)a, shows the current distribution at the frequency 1ghz, from the figure it can be noticed that the maximum current is 54.8 a/m and most concentration of the current is on the feed line. figure (13)b, shows the current distribution at frequency 2.4ghz, from the figure it can be noticed that the maximum current equal to 66.1 a/m and most concentration of the current on the feed line and around the sides of the upper slot. figure (13)c, shows the current distribution at the frequency 3.1ghz, from the figure it can be noticed that the maximum current is163a/m and most concentration of the current around the sides of the upper slot. figure (13)d shows the current distribution at the frequency 4ghz, from the figure it can be noticed that the maximum current is 38.8 a/m and most concentration of the current at most parts of the feed line and around the sides of the lower slot. figure 13. the current distribution of the staircase patch antenna with slots at different frequencies. 3.6. 3-d radiation pattern the 3-d radiation pattern of the staircase patch at different frequencies is shown in figure (14). the directivity over the phi and theta angels for the proposed antenna can be shown by these plots. for the frequencies 1ghz, 2.4ghz and 3.1ghz, the maximum directivity is 2.59 dbi, 3.69 dbi and 5.96 dbi respectively. the radiation pattern for frequencies 1ghz and 2.4ghz are omnidirectional radiation pattern and for 3.1ghz is quasi omnidirectional radiation pattern. figure 14. the 3-d radiation pattern of the antenna for different frequencies. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 173 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.6. e-plane, h-plane radiation pattern figure (15) shows the e-plane and h-plane for the frequencies 1ghz, 2.4ghz and 3.1ghz. figure (15) a shows e-plane and h-plane for 1ghz, e-plane has main lobe magnitude equal to 2.59 dbi, main lobe direction is -176degree, angular width (3db) is 81.2 degree, h-plane has main lobe magnitude equal to 1.26 dbi, main lobe direction is -7degree, angular width (3db) is 89 degree. figure (15)b shows e-plane, h-plane for 2.4 ghz, e-plane has main lobe magnitude equal to 3.23 dbi, main lobe direction is -20degree, angular width (3db) is 66 degree, h-plane has main lobe magnitude equal to 3.23 dbi, main lobe direction is 147degree, angular width (3db) is 53 degree, side lobe level angular width (3db) is -7.6db. figure (15)c shows e-plane, h-plane for 3.1ghz, e-plane has main lobe magnitude equal to -0.095 dbi, main lobe direction is 46degree, angular width (3db) is 47 degree, side lobe level is -1.3db, h-plane has main lobe magnitude equal to 5.99 dbi, main lobe direction is 57degree, angular width (3db) is 37 degree, side lobe level is -1.6db.. figure 15. e-plane, h-plane of staircase patch antenna with slots at different frequencies. journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 174 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.7. group delay the group delay of staircase patch antenna with slots is shown in the figure (16). it can be observed that group delay is less than 2ns in the most of the band, which means minimum distortion occurs on the pulse, because the group delay is constant in almost all the ranges of frequencies. figure 16. the group delay versus frequency for staircase patch antenna with slots. table 2 which is shown below, illustrates a survey comparison between this work and the work in the reference [9]. from table 2, it can be noticed that the antenna in the reference [9] covers three separated band, but this work covers a wider bandwidth equal to 3.92 ghz, with acceptable gain ranging from 2.18 dbi to 5.3 dbi, and also can be made a size reduction of the antenna by 42.86% as compared to the antenna in reference [9]. table 2. comparision between this work and work in the reference [9]. conclusion a staircase broadband microstrip patch antenna operates in the 2g/3g/4g mobile base station has been proposed. the key of the design is the use of a stepped patch to enhance the matching between the antenna and the transmission line. the proposed antenna operates in the frequency range from 0.86 ghz to 4.78 ghz, and gives gain ranging from 2.18 dbi to 5.3 dbi. the antenna is designed using multiple slots configuration, with optimization techniques implemented on it to achieve the best possible desired results. the proposed antenna with slots is fabricated and tested practically using ms46-42a vector network refrences bandwidth (ghz) gain (dbi) dimensions(w×l×h) mm3 ref [9] (0.68-0.821)&(0.86-0.96) (1.56-2.15)&(2.13-2.495) (0.89-2.47) (230×176×0.8) this work (0.86-4.87) (2.18-5.3) (100×120×1.542) journal of al-qadisiyah for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 175 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. analyzer (vna), and the result of s11 is compared with simulation result, it is observed that the practical result agree with simulation result and a slight difference is attributed to the fabrication errors. references 1. m.s.el, gendy; h.h., abdullah, e.a.; gendy, e.a, abdallah, mobile base station dual band microstrip antenna, electronics research institute, dokki, giza, egypt, 2014 ieee. 2. c. a., balanis, antenna theory analysis and design, third edition, 2005. 3. y., entiefa mansour, single slot dual band microstrip antenna for wimax application, atilim university, thesis 2014. 4. ankur kaushal; sachin tyagi, microstrip patch antenna, its types, merits demerits and its applications, "international journal of engineering sciences & research technology, 2015. 5. ahmed fatthi alsager, design and analysis of microstrip patch antenna arrays, electrical engineering– communication and signal processing, college of borås, 2011. 6. sven erik sandström; muhammad ishfaq ; raja sheharyar khan, a compact microstrip patch antenna for lte applications, school of computer science, physics and mathematics 2013. 7. amit das; prof., asish dubey, broad band microstrip patch antenna designa critical review, international research journal of engineering and technology (irjet), 2017. 8. dhanraj meena; r.s., meena, triple band u-slot microstrip patch antenna for wlan and wireless sensor applications, international conference on communication,control and intelligent systems (ccis) 2015. 9. sultan shoaib; imran shoiab; nosherwan shoaib, compact and printed mimo antennas for 2g/3g and 4g-lte mobile tablets, ieee 2015. chapter one introduction al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 studying the effects of the super plasticizer on the concrete mixes containing differernt portion of cement jabbar a. laftah professor in structural engineering at technology university. email: wifi120@gmail.com received 20 may 2015 accepted 24 march 2016 abstract: the included search casting twenty one concrete mixes, that proportion are (1:1.5:3), (1:2:4) and (1:3:6). nine of them with out using plasticizer with three (w/c) (0.50, 0.57, 0.60) as showing at table (6).and twelve mixes contained a proportion of additive mixture of metal gelenium no.(5) with four ratios of gelenium as shown at table (5) and every mix has (w/c) (0.45:0.53:0.60). soft conceret of non container plastizer tested by workablity (slump test). the mex (1:1.5:3) gave best result (60mm) , least mix (1:2:4) gave (40mm), least mix(1:3:6) gave (25mm) according to reference mixture. soft conceret with gelenium ratio plastizer gave best slump for nine mixs with three (w/c) ratio (40%, 45%, 50%) and gelenium (3%) , the best result for mix(1:1.5:3) equal (98mm),least mix (1:2:4) gave slump (85mm) , and mix (1:3:6) gave (74mm) compare with reference mixture compressive strength for twelve cupics with optimum gelenium ratio. the mix (1:1.5:3) with (2%) gave (14mpa) at early age. and (38mpa) at finish age, least mix (1:2:4) gave (10mpa) at early age and (28mpa) at finish age , and mix (1:3:6) gave (6mpa) at early age , and (20mpa) at finish age as shown at figure(8). depend on ratio of mix , percentage(w/c) and zoom of plasticizer .these factors gave best result at mix(1:1.5:3) according to standard specification. keywords: plasticizer, concrete mix, admixture, compressive strength, workability, durability, slump, gelenium (5). الخالصة: . تسعة منهاا بانون مضااب وثاثالث (1:3:6( و)1:2:4(، )1:1.5:3خرسانية بثالث نسب وهي ) ( خلطة12تضمن هذا البحث ) ( وثنسب مختلفة 5رقم) ومكلينيالمضاب واثناعشر خلطة حاوية على ارثعة نسب من . ( w/c( )0.5, 0.57 , 0.60) نسب ماء .(%50 ,%45, %40من الماء ) فالخلطااة ( لمعرفاة قابلياة التشا ي 5فحا الهطاول للخلطاتالخرساانية ال يار حاوياة علاى المضااب كلينياوم رقام ) ( 1:3:6(ثاام تليهااا الخلطااة)40mm( اعطااأ )1:2:4( تليهااا الخلطااة )60mm( أعطااأ أفضاا النتااات بل ااأ )1:1.5:3) ( مقارنًة بالخلطة المرجعية.25mmأعطأ ) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 ( وثااثالث نسااب لل)لينيااوم فلعطااأ الخلطااة 5فحاا الهطااول للخلطاااأ الخرسااانية الحاويااة علااى ال)لينيااوم رقاام ) (1:1.5:3( )98mm( تليها الخلطة )85(التي اعطأ )1:2:4mm( ثم تليها الخلطة )64(فلعطأ هطواًل )1:3:6mm ) مقارنة بالخلطة المرجعية. %2للخلطاأ الحاوية على ال)لينيوم المثالي وثاثالث نساب ) فحصأ مقاومة األنض اط بلرثعة وعشرون مكعباً -:( وكما مبين w/c( )40%, 45% , 50%وثثالث نسب ) (4% , 3% ,  ( 1:1.5:3الخلطاااة) ( 14( أعطاااأ مقاوماااة )%2وثنسااابة كلينياااومmpa(فاااي األعماااار المتقنماااة و )28mpa ) لألعمار المتلخرة  ( 3( بنسبة كلينياوم )1:2:4أما الخلطة% )( 10أعطاأ مقاوماة فاي األعماار المتقنماةmpa ومقاوماة لألعماار ) (.25mpaالمتلخرة )  ( 1:3:6أما الخلطة) (6( فلعطاأ مقاوماة فاي األعماار المتقنماة )%4وثنسابة كلينياومmpa ومقاوماة لألعماار ) (.8( وكما مبين في الجنول )20mpaالمتلخرة ) المااااء للساامنأ وكميااة الجرعاااة المضااافة ماان ال)لينياااوم األنضاا اط يعتماان علاااى عواماا هااي نسااابة الخلاا ونساابة ( مقارنًة بالمواصفاأ القياسية.1:1.5:3فالجرع المثالية أعطأ أفض النتات وخاصًة للخلطة ) introduction: use of concrete began in year 1850 a.c twenty five years after the discovery of portland cement by the engineer aspidin. after this period, standards specification was needed for the plane and reinforced concrete. there is standard specification for this material in many countries. the importance of use of concrete was increased since 1900 a.c and there were developments in construction especially in dams that made the concrete the first material contributes most of the new buildings. plane concrete is made by mixing cement with water, sand and crushed stone or a gravel. cement works as an active material in this mix where in combine physically and chemically producing stiff mass like natural stones. when cement is mixed with water only it's called "cement paste" and the hardened cement paste is called "stony cement". the use of only cement and water in the mix is expensive so, aggregate is used to increase the volume of the concrete mix. the components of the concrete are mixed within different ratios depending on their purposes in the mix. one of the concrete properties is that it takes the desired shape when casted in the frames. good mix of concrete produces a solid material which can bear the compressive stress but it is weak in bearing the tensile stress therefore amount of steel is added in the zones where tensile stress is present to increase the tensile strength property and this called reinforced concrete(jack. c. mc,cormac,2001). concrete is a nonhomogeneous material consists of particles different in size and shapes placed randomly and tied together by hardened cement. concrete consist of pores and spaces filled with water and air. this combination of concrete identifies its physical and chemical properties.rixon"m:r"1986 physical and chemical phenomena that happens during hardening of concrete (like crystallization, gel shrinkage and evaporation of excess water … etc.) lead to change the concrete properties with time(b. w. shack,1974). first portland cement was produced in year 1840 by pakar, he called it the roman cement which has a flexibility to a certain degree. stones from top of sheppy island that lies on the mouth of the al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 river thames was used in producing the portland cement after burning and crushing(lea, ''the chemistry of cemente and concerete'' arnold ,1970) after this discovery, normal or natural cement appeared in england, france and russia. in general, this cement contained (70%) calcium carbonate (caco3), (20%) silica (sio2) and (10%) alumina (al2o3) that represent the main components of the present cement noting that this type of cement was damaging quickly because of its fast hardening. the developments that occurred to the cement in france by viket was by mixing water with four parts of lime to one part of clay which is crushed and burnt and the crushed again to produce cement looks like present portland cement although it is not with the same fineness. since that time until now the industry of cement developed so its types differed but still the main mix of producing it is clay and lime. admixtures include some materials (except aggregate, cement and water) which are added in a low percentages to the concrete mix during mixing process in order to give the fresh or hard concrete some properties like:  improve workability.  increase or decrease setting time.  decrease the rate of losing slump.  increase the ability of pumping.  increase the initial strength.  to gain a high strength concrete.  improve the general properties of hard concrete. use of plasticizers leads to increase the concrete through increasing the flow ability of the concrete mix by increasing the ratio of the plasticizer and the optimum admixture ratio added as a weight ratio of the cement in use (mehta, p. k. 1986). material reducing water (plasticizers): of the most important materials used from the chemical side: 1. lignosulphonates : it is a complex material form (20%) of the combination of the wood produced in the paper industry as the product of an accidental. the commercial product thereof which is used as an additive composed of calcium or sodium by sugary basis with ratio (1-30%). 2. acids alhaadroxa carbosel: it is an organic material containing both alhaadroxa and carboxyl in the molecular structure. are produced from the purification process of raw materials, whether chemical or biological way therefore have a high purity. the primary use of this material is in the food and pharmaceutical industries. when these materials are in salts of sodium be of high solubility but andjemadha point and low , and most important of these acids are: 1. citric acid. 2. tartaric acid. 3. mucic acid. 3. hydroxylated polymers: produced in the manufacture of some vegetable oils in the partial hydrogenation processes for the production of polymers with low molecular weight and therefore contains glucose units which number between (3 & 25). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 255 4. salts of sulfuric acid for naphthalene formaldehyde: the commercial materials of this type contain (25-45%) of the solids content increasing this content is for the purpose of self-concrete production father with content ranges between (13%) of the cement weight. 5. sulfate salts of melamine formaldehyde: this type of chemicals were produced initially for various uses in the industry. materials and laboratory tests: 1. laboratory materials cement: portland cement was used ordinary course of opc and the corresponding iraqi standard specifications (no.5 / 1984) as shown at table (2). fine aggregate: been using sand as a fine aggregate were examined gradient and the proportion of salt in it and found that it is identical to the iraqi specifications (no.5 / 1984). table (2) shows the limits of this number where it is located within the region (3) of the standard gradient zones no. 4, according to british and iraqi specifications. coarse aggregate: natural gravel was used as coarse aggregate in experimental mixtures and in size maximum (20 mm). gradient and the proportion of salts were examined and found that it is identical to the iraqi specifications (no.5 / 1984). table (4) shows the limits of the gradient of the gravel and table (4) shows some characteristics for sand and gravel used. additive plasticisers: gelenium (5) was used which is composed mainly of organic matter (modified atheer carboxyl). this material is working to increase the negative charge on the surfaces of cement particles causing dispersion and divergence of cement particles due to the electronic powers generated. table (5) shows the properties of this plasticizer. 2. methodology * mixes samples of test mixes were made which contained different ratios of cement. twentyone mixes were chosen, mix (1:3:6) cement / aggregate ratio (1:9), mix (1:2:4) cement / aggregate ratio (1:6) and mix (1:1.5:3) cement / aggregate ratio (1:4.5) nine mix without gelenium and twelve with gelenium listed in flow chart (1) shown. optimum plasticizer ratio which is added to every mix was determined as to give (100 10 mm) slump. suitable w/c ratio was determined also. it is noted that mix (1:3:6) is poor with cement. cement amount increases in the mix (1:2:4) and mix (1:1.5:3) the most amount of cement compared with the other two mixes. the details of mixes and ratios made them up are listed in tables as follows in the research. 3. laboratory tests 3-1 slump test: this test was made according to the american standard specification (astm.c.143, 1989). the device consist of a conical cylinder, the upper base diameter (10 cm) and the lower one al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 (20 cm) with height of (30 cm). the cylinder is filled with three equal layers compacted by a (16 mm) diameter steel stick (25) times then the surface is well adjusted. the cylinder at last is raised slowly and then slump is measured to the nearest (5 mm). 3-2 compressive test: compressive tests were made using cubic samples with (15×15×15 cm) dimensions according to british standard specification (b.s.1881, part 116, 1989). in every test average of three samples is taken. results: 1. water reduction: this ratio was determined to declare the effect of the plasticizers in reducing the amount of water with keeping the same plasticity of the mix that is represented by the slump (100 10 mm). several mixes with different ratios of plasticizer and the optimum ratio of the plasticizer for all three mix is determined. table (6) shows the magnitude of the reduction (wr) for the three mixes as shown in figures (1), (2) and (3). when the relation between the plasticizer ratio and the reduction ratio for every mix are drawn, the optimum ratio of the plasticizer as weight proportion of the cement weight that achieves slump (100 10mm). mix the optimal ratio of plasticizer of cement weight 1:3:6 4% 1:2:4 3% 1:1.5:3 2% the equation used to measure the reduction of water using plasticizer as a percentage is: it is noted that the optimum plasticizer ratio that gives the higher reduction amount is in the mixes that is rich with cement in which there is an enough reduction in water. this means that it is possible to produce mixes of high workability with little ratio of water because the amount of cement paste is enough to give enough plasticity with respect to mixes in which the ratio of cement is low and needs more water. 2. slump: slump test was made to the test mixes with different ratios of water and without addition of plasticizer. table (6) shows the slump test results which are also shown in figures (4), (5) and (6). through the results it is noted that the amount of water needed to have a specified slump decreases with increasing cement ratio in mixes i.e. whenever the aggregate ratio increases in the al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 mix and the cement paste decrease, more amount of water is needed to restitute the effect of cement paste which is the covering the surfaces of the coarse, greasing and lubrication these surfaces (a.m , nevel ''properties of concerete '' 2005). when adding optimal percent of plasticizers material to mixes and achieve the approximate amount of slump (100 10 mm), the water / cement ratio decreased to achieve such slump and became as follows: 1(1:3:6) w/c = 0.50 2(1:2:4) w/c = 0.45 3(1:1.5:3) w/c = 0.40 by comparison, we find that the mix (1:3:6) when it is without plasticizer and with water/cement = 0.50, the slump is not more than (5 mm), but when plasticizers material is added at the same value, or the percentage of water, it is found that slump increases to (100 10 mm) as well as the case of the mix (1:2:4). the mix (1:1.5:3) when it is without plasticizer material and with water to cement ratio (0.4), the amount of slump = 3.5 mm and when plasticizers is added at the same percentage of water to cement, the slump increases to (100 10 mm). 3. compressive strength: compressive strength was determined for the test mix of age (3,7,28) the day before and after the addition of plasticizers to see how much influence in increasing compressive strength. the obtained results shown in the table (7) and illustrations figures (7), (8) and (9) show an increase in resistance to compression as follows for the three mixtures: 1at age 3 days compressive strength increased by (44%) 2at age 7 days compressive strength increased almost by (30%) 3at age 3 days compressive strength increased almost by (16%) from the results, it is evident that the increase will be more in the early stages compared with the subsequent stages and explanation of that is the reactions are more severe and more influential in the early stages, but this effect is reduced in the later stages of the life of concrete. discussion: 1plasticizer materials affect the fresh concrete better when cement amount is enough which leads to increase the slump to (4) times comparing to the mixes that doesn't contain admixtures. 2the optimal ratio of plasticizer that achieves a water reduction (wr) become greater in mixes that are poor with cement, for example: mix (1:3:6) requires (4%) plasticizer while mix (1:1.5:3) requires (2%) plasticizer, i.e. half amount of the proceeding mix. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 3use of plasticizer materials in this research helped in reduction of water which led to increase the compressive strength with an accepted ratios for the four mixes at ages (3, 7, 14 , 28) days and it is noted that the increase is greater at early stages compared to late stages. 4addition of water to mixes that are rich with cement is more effective in increasing the slump compared to mixes that are poor with cement because in rich mixes there is alot of fine particles which helps to increase the mix plasticity and flow ability. conclusion:  workability increase with adding optimum percentage of admixture gelenium no (5).  compressive strength increase at early age because of hydration and reach to high value of strength.  mix (1:1.5:3) with gelenium (2%) and (w/c)=(0.4) gave compressive (38mpa) at (28days).  mix (1:2:4) with gelenium (3%) and (w/c)=(0.45) gave compressive (28mpa) at (28days).  mix (1:3:6) with gelenium (4%) and (w/c)=(0.5) gave compressive (20mpa) at (28days). all these result according to standard specification. flow chart working search الخلطات الخرسانية mixing conceret (9) mix (without gelenium) (12) mix (with gelenium) mix 1:1.5:3 1:2:4 1:3:6 1:1.5:3 1:2:4 1:3:6 (1)w/c 0.5 0.5 0.5 0.4 0.45 0.5 (2)w/c 0.57 0.57 0.57 (3)w/c 0.6 0.6 0.56 references: [1] al-hadithi, r. y., "durability of high performance concrete incorporating high reactivity metakaoline and rice husk ash", m. sc. thesis, university of technology, 2003, p.58. [2] al-wahili, a.m., "mechanical properties of high reactive powered concrete", m. sc. thesis, university of technology, november, 2005. [3] a.m.nevel "properties of concrete'' long man group limited london 4th edition. [4] astm 143-1989, "standard test method for slump of hydraulic cement concrete", annual book of astm standard american society for testing and materials, vol.04.02, 1989, pp.85-86. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 252 [5] b.s 1881, part 116, "method of determination of compressive strength of concrete cubes", british standard institute, 1989, pp.3. [6] b.w.shacklock''concerete constituents and mix properties '' cement and concerete association 1974. [7] d.f.orchad''concerete technology practice'' 3rd edition vol,2 , applied 1973. [8] gelenuim modified anther carboxy-2003. [9] iraqi specification no.5/1984, "aggregates from natural sources for concrete and construction". [10] iraqi specification no.5/1984, "portland cement". [11] lea''the chemistry of cement and concrete'' arnold -1970 [12] mehta.p.k ''concrete structure properties and materials englewood cliffs ,new jersy – 1986. [13] rixom, m. r., mailvaganam, n. p., "chemical admixtures for concrete", second edition, new york, us, 1986, p.34. table (1): properties of cement no. test setting time value limit of iraqi std. spci. 1 inatial time final time 118 menite 3.1 hours 45<= 10>= 2 compressive 3 days 7 days 18.7mpa 26.4mpa 15<= 23<= gradation of the sand used in mixes): 2table ( size (mm) % passing standard specifications (no.5/1984) 9.5 100 100 4.75 93 90-100 2.36 95 85-100 1.18 82 75-100 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 0.60 76 60-79 0.30 19 12-40 0.150 6 0-10 gradation of the gravel with maximum size (20 mm)): 3table ( size (mm) % passing standard specifications (no.5/1984) 37.5 100 100 20 90 85-100 10 13 0-25 5 3 0-5 physical properties of sand and gravel): 4table ( specific weight sulfate salts ratio absorption sand 2.63 %*0.5>0.06 0.75% gravel 2.650 %*0.5>0.02 0.63% * according to iraqi standard specification no. 45 / 1980. table (5): plasticizers properties color dark density 1.1 gm/cm 3 at 20 o c ph 6.6 viscosity 128s at 20 o c table (6): water reduction in the mixes with different plasticizer ratio mix (1:3:6) w/c = 0.5 mix (1:2:4) w/c = 0.45 mix (1:1.5:3) w/c = 0.40 plasticizer ratio (%) reduction ratio (%) plasticizer ratio (%) reduction ratio (%) plasticizer ratio (%) reduction ratio (%) 3 12.5 2 15 1 22.5 3.5 13.75 2.5 18 1.5 25 4.5 12.5 3.5 18.5 2.5 27 5 10 4 17 3 25 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 table (7): slump (mm) without plasticizer mix (1:3:6) mix (1:2:4) mix (1:1.5:3) w/c slump w/c slump w/c slump 0.50 5 0.45 5 0.40 35 0.57 10 0.50 20 0.43 45 0.60 25 0.53 40 0.45 60 table (8): slump (mm) with plasticizer w/c 1:1.5:3 gelenium% slump w/c 1:2:4 gelenium% slump w/c 1:3:6 gelenium% slump 0.4 1% 80mm 0.45 2% 77mm 0.5 3% 60mm 0.4 1.5% 90mm 0.45 2.5% 82mm 0.5 3.5% 70mm 0.4 2.5% 120mm 0.45 3.5% 122mm 0.5 4.5% 85mm 0.4 3% 140mm 0.45 4% 130mm 0.5 5% 125mm table (9): compressive strength of mixes with and without plasticizer age (day) mix (1:3:6) mix (1:2:4) mix (1:1.5:3) without plasticizer with optimal plasticizer ratio without plasticizer with optimal plasticizer ratio without plasticizer with optimal plasticizer ratio 3 6 8 8 10 9 14 7 12 16 16 20 20 26 28 20 22 24 28 26 26 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 figure (1): the percentage of water reduction by adding plasticizers for the mix (1: 3: 6) water to cement ratio (0.50) figure (2): the percentage of water reduction by adding plasticizers for the mix (1: 2: 4) water to cement ratio (0.45) 9 10 11 12 13 14 15 2 2.5 3 3.5 4 4.5 5 5.5 r e d u ct io n r a ti o plasticizer ratio of cement weight 15 16 17 18 19 20 1.5 2 2.5 3 3.5 4 4.5 r e d u ct io n r a ti o plasticizer ratio of cement weight al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 figure (3): the percentage of water reduction by adding plasticizers for the mix (1: 1.5: 3) water to cement ratio (0.40) figure (4): slump of mix (1:3:6) without plasticizer. 22 23 24 25 26 27 28 0.5 1 1.5 2 2.5 3 3.5 r e d u ct io n r a ti o plasticizer ratio of cement weight 0 0.5 1 1.5 2 2.5 3 0.49 0.5 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.6 0.61 s lu m p water cement ratio w/c al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 figure (5): slump of mix (1:2:4) without plasticizer. figure (6): slump of mix (1:1.5:3) without plasticizer. 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0.44 0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 s lu m p water cement ratio w/c 3 3.5 4 4.5 5 5.5 6 6.5 0.39 0.4 0.41 0.42 0.43 0.44 0.45 0.46 s lu m p water cement ratio w/c al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 225 figure (7): compressive strength of mix (1:3:6). figure (8): compressive strength of mix (1:2:4). 0 2 4 6 8 10 12 14 16 18 20 22 24 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 c o m p re ss iv e s tr e n g th age (day) without plasticizer with plasticizer 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 c o m p re ss iv e s tr e n g th age (day) without plasticizer with plasticizer al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 figure (9): compressive strength of mix (1:1.5:3). 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 c o m p re ss iv e s tr e n g th age (day) without plasticizer with plasticizer al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 148 effects of superplasticizer admixture on the mechanical behaviour of lightweight concrete mixes containing mineral additives dr. adnan flayih hassan al-sibahy civil engineering department, the university of al-qadisiya, iraq adnan_flayih@yahoo.com received 6 december 2015 accepted 21 january 2016 abstract this paper presents an experimental investigation of the effect of a superplasticizer admixture on the mechanical behaviour of expanded clay lightweight concrete containing metakaolin material and recycled glass aggregate. the optimum dosage of the superplasticizer admixture (type snf) was adjusted and used by weight of cement. the short and long-term mechanical properties of concrete mixes were measured in accordance with the relevant british / en standards. the obtained results were compared with the results of control concrete mixes (without superplasticizer). the results obtained showed that the superplasticizer admixture exhibited a 20% reduction in content of mixing water. all measured values of unit weight, compressive and splitting tensile strengths increased when the superplasticizer admixture is used. the concrete mix containing 30% recycled glass revealed an increase in the mechanical strength compared with the mix of 15% recycled glass. however, the workability of the superplasticizer concrete mixes was degraded, reaching 44% reduction in slump value. keywords: superplasticizer admixture, lightweight aggregate concrete, metakaolin, recycled glass, mechanical behaviour. تأثير الملدن المتفوق على التصرف الميكانيكي للخرسانة الخفيفة الوزن والحاوية على المضاف المعدني لخالصة:ا المتفوق على السلوك الميكانيكي لخرسانة الطين المتمدد الحاوية على الملدن يستعرض هذا البحث دراسة عملية للتحري حول تاثير مادة الميتاكولين والركام الناتج من تدورير مخلفات الزجاج. النسبة المثلى من الملدن المتفوق تم ضبطها واُستخدمت كنسبة من لخرسانية باالعتماد على المواصفات القياسية وزن االسمنت. الخصائص الميكانيكية القصيرة والبعيدة االمد تم قياسها للخلطات ا البريطانية. النتائج المستحصلة قورنت مع تصرف الخلطات القياسية ) غير الحاوية على مضاف الملدن المتفوق(. % نقصان في كمية ماء الخلط. كل االختبارات الخاصة بقياس وحدة 02يبدي أظهرت النتائج المستحصلة إن الملدن المتفوق الوزن، مقاومة االنضغاط ومقاومة شد االنشطار اظهرت زيادة في قيم هذه الخصائص عند استخدام الملدن المتفوق. الخلطة % ركام الزجاج 51ية الحاوية على % ركام الزجاج المدور أظهرت نتائج اعلى منها للخلطة الخرسان02الخرسانية الحاوية على .%44تاثرت حيث وصلت الى نقصان مقداره المدور. على كل حال، القابلية التشغيلية للخلطات الحاوية على مضاف ملدن mailto:adnan_flayih@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 149 1 introduction improving the mechanical strength of lightweight concrete has recently been the subject of many published research into construction materials. environmental criteria have been also considered with regard to reducing the impact of waste disposal in land fill by reusing these waste and byproduct materials as construction materials [1]. one of the main techniques which has been used in developing the strength of concrete is the use of admixtures. the superplasticizer sp (also known as high range water reducer) is often used in both the concrete industry and on construction sites. different kinds of superplasticizer admixtures are available. they have similar conjunction roles in triggering dispersive action on the surface of hydration cement particles during the initial hydration reactions [2]. the active ingredients of these products are commonly based on an anionic polymeric surfactant [3]. the molecules of superplasticizer coat the cement grains and change their orientation, causing them to repel one another [4]. two contrasting properties can be achieved with a superplasticizer admixture: either an increase in workability, combined with retention of the strength level, or the opposite. the superplasticizer action causes re-arrangement of the cement particles, resulting in more regular and allowing better hydration. several models have been suggested to explain the effect mechanism of superplasticizer on the cement hydration process [2]. one of these models is the adsorption mechanism which attributes the effectiveness of the superplasticizer to the adsorption behaviour of the admixture on the cement particles. it was proposed that the elementary processes were based on both adsorption and desorption [5]. another study reported that the superplasticizer was capable of reducing the surface tension of water. this permits penetration of the molecules in between the solid particles and produces much denser mixes, which consequently reduces the tendency of permeable water [6]. the results of fluidising due to use of superplasticizer admixtures are affected by several parameters: for example, dosage of the superplasticizer; type and quantity of aggregate and cement used; mixing procedure and temperatures [7]. a growing number of alternatives to the traditional ingredients of concrete mixes have surfaced in recent years. this is as a consequence of the need to reduce the demand on natural resources created by construction materials. one of these alternative materials is recycled glass aggregate. it has been used as an entire or partial replacement for both fine and/or coarse aggregate [8-12]. this approach is useful to mitigate the impact of waste glass which is produced in large amounts every year. the inclusion of glass aggregate in concrete mixes causes an increase in the expansion phenomena due to the alkali–silica reaction (asr) produced [8-16]. however, this reaction can be reduced by using mineral additives [8, 16]. metakaolin (mk) is an example of such a mineral by-product materials. it has a higher pozzolanic ratio and is used as a partial replacement for cement, and has received considerable interest for its applications to construction. the main effects of using metakaolin are the improvement of the strength and durability of concrete mixes [17-24]. an attempt to develop the mechanical strength of a newly modified lightweight concrete using a superplasticizer admixture in conjunction with metakaolin was experimentally investigated in this study. this type of lightweight concrete contains different ratios of recycled glass and uses expanded clay as a coarse aggregate. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 150 2 experimental details 2-1. materials the main ingredients of the concrete mixes were ordinary portland cement, natural sand, expanded clay, recycled glass, metakaolin and superplasticizer admixture. locally available ordinary portland cement complying with the iraqi standard no.5 [25] was used in this study. natural sand for building purposes was used as a fine aggregate with a grading which complied with bs en 12620[26]. a medium-grade 8-5r of techni clay expanded clay was used as coarse aggregate. the moisture content and particle density of the expanded clay were 20% w/w and 550 kg/m3 respectively. recycled glass aggregate with particle sizes of 0.5-1 and 1-2 mm was used as a partial replacement for natural sand by volume with two levels: 15% and 30%. metastar 501metakaolin material [28] with a constant content (10%) was adopted as a partial replacement for ordinary portland cement. the daracem sp6 superplasticizer admixture of the sulphonated naphthalene formaldehyde condensate snf [29] was used throughout this study, its performance complies with bs en 9342[30]. it’s maximum chloride and alkali contents were < 0.1% and 0.5% by mass respectively. the mixing operation was carried out according to bs en12390-2 [31]. the fresh concrete was cast in moulds in three layers; each layer was completely compacted. after casting, the samples were kept in laboratory conditions and covered with a nylon sheet to ensure a humid atmosphere around the specimens. after 24 hours, the samples were demoulded, marked and immersed in a basin of water at a temperature of 20 ± 2 ˚c until the date of the test. 2-2. selection of the superplasticizer content in this experimental programme, the workability of the concrete mixes was kept constant, while the strength level was intended to be increased. on this basis, the content of the superplasticizer was adjusted based upon the fluidity features of the reference lightweight concrete mix (0% g+0%sp+0%mk), which possesses a w/c of 0.45. in order to maintain a constant slump (50± 5 mm), multi-trial mixes were carried out and the w/c resulting from using the superplasticizer admixture was calculated each time according to the following equation [32]: ⁄ ⁄ ( ) (1) where and are, respectively, the concrete mix containing superplasticizer and the reference concrete mix . since the experimental work scheme was concerned with improving the mechanical strength of the concrete mixes, it was found that 2% superplasticizer by weight of cement was the optimum admixture dosage. this dosage produced higher compressive strength (19.7 mpa at 28 days age) with a maximum water reduction of 20%, equivalent to a w/c of 0.36. in accordance with these results the optimum superplasticizer content was chosen to produce two modified concrete mixes containing expanded clay, recycled glass and metakaolin materials (superplasticizer mixes). the measured mechanical properties of the former mixes were then compared with concrete mixes with the same constituents without superplasticizer (control mixes).the details of the concrete mixes which were adopted in the experimental programme are shown in table 1. 2-3. test programme the experimental programme tests included studying the fresh properties, unit weight, compressive strength, splitting tensile strength and stress-strain behaviour. all of these tests were conducted according to the relevant bs / en standards [33-36]. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 151 the short and long-term mechanical properties of the concrete mixes were experimentally measured. except for the stress-strain behaviour test which was carried out using two cylindrical specimens, an average value of three specimens was taken for each test result. 3 results and discussion 3.1 properties of fresh concrete mixes the behaviour of the fresh status of the concrete mixes in terms of consistency was carried out using a slump test; the obtained results are shown in figure 1. it can be seen that the workability aspect was degraded when the superplasticizer was used in producing the modified concrete mixes. a clear decrease in the value of the slump was recorded for both superplasticizer mixes, and further compaction work using a poker vibrator was required to overcome the drying condition of these mixes. this could be due to the accelerating effect of superplasticizer admixture, which becomes more effective in the presence of metakaolin material. in turn, this causes rapid hydration of the cement particles and reduces the fluidity time of the concrete mixes. the same cannot be said for the control mixes, where the consistency was still found to be within the acceptable range of workable concrete (50±5 mm). however, the concrete mixes with a glass content of 30% showed a lower reduction in the workability aspect than that of the mixes with 15% glass content. such behaviour can be attributed to the role of the glass particles in providing extra moisture content for the concrete due to their adsorbing the mixing water [8-16]. 3.2 unit weight figure 2 shows the test results of unit weight for the control and superplasticizer concrete mixes at different test ages. the superplasticizer concrete mixes exhibited higher densities than the control mixes. this may be related to the penetration of the superplasticizer fluid and coating of the solid particles, thereby producing a denser mix [6]. the concrete mixes containing 30% glass ratio showed higher densities than those of the samples with 15% glass ratio. this may be attributed to the capability of these mixes to hold the water particles due to the lower tendency of the glass aggregate to absorb the mixing water [8-16]. in general, except at 28 days’ age, both the superplasticizer and the control lightweight aggregate concrete mixes exhibited a continuous decrease in density over time. this behaviour may be caused by two phenomena: the first is the consumption of water by hydration processes and the second is the reduction of free water inside gel pores by evaporation. the increase in density of the concrete mixes at age of 28 days compared with their density at 7 days could be explained by the greater level of hardness due to the pozzolanic reaction of the metakaolin material at this age. furthermore, acceleration of the cement hydration process can be accounted by the presence of the superplasticizer which provides better water distribution for the cement particles. 3.3 compressive strength the compressive strength test results are presented in figure 3. this figure indicates that the superplasticizer concrete mixes possess higher compressive strength values than the control mixes. this result is in agreement with previous studies [1-7]. furthermore, the presence of metakaolin material, which is a mineral admixture, plays a role in increasing the compressive strength in conjunction with the superplasticizer admixture. the main significance of the induction of metakaolin material are its role as a filler and, an accelerator for the hydration of portland cement, as well as its pozzolanic properties [17-18]. for the superplasticizer concrete mixes, the concrete mix containing 30% glass produced a higher compressive strength value than that of the mix with 15% glass content. this can be explained by more water being available inside this mix which allows further hydration processes to take place. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 152 for all of the concrete mixes, the compressive strength value increased with increased curing time. the percentage increases in compressive strength for the concrete mixes containing the superplasticizer admixture with 15% and 30% glass ratios at an age of 90 days relative to the control concrete mixes of the same age were 4% and 8.5 % respectively. satisfactory failure modes were observed for all concrete samples after the compressive strength test had been conducted which comply with bs en12390-3[35] mode-a. all four exposed faces were cracked approximately equally, with a little damage to the faces in contact with the platens without any explosive failure, as shown in figure 4. the pozzolanic reactivity of metakaolin material which, is described in bs en 196-5[37] was measured according to the values of compressive strength as in [20]. this was done by comparing with the results of reference mix (0%g+ 0% mk+ 0% sp). the same approach also used to predict the pozzolanic reactivity of metakaolin in conjunction with the superplasticizer admixture on the strength of the concrete. the specific strength ratio which is an indicator of the contribution of the mineral admixture and/or the superplasticizer to the strength of the mixture is defined as: ⁄ (2) where is the compressive strength in mpa and is the hydraulic cement of mineral and/or superplasticizer admixture percentage. by eliminating the reduction effect of the glass aggregate on the values of compressive strength, the contribution of the pozzolanic effect of metakaolin and/or superplasticizer to the strength of concrete is given by eq. 3. (3) where is the contribution of unit hydraulic cement when metakaolin and/or superplasticizer is used and the contribution of unit hydraulic cement to the concrete strength without using metakaolin and/or superplasticizer. the index specific strength is the ratio of to . the contribution of pozzolanic effect and/or superplasticizer to the concrete strength can be expressed as: ( ⁄ ) (4) the values of , , and for the reference, control and superplasticizer concrete mixes at ages of 7,28, 90 and 180 days were calculated and are presented in table 2. the contribution of metakaolin and the superplasticizer admixture to the compressive strength of the concrete was plotted in figure 5. for both control concrete mixes, the improvement in compressive strength due to the pozzolanic effect of metakaolin exhibited a long-term duration (180 days).this is in agreement with the results of [38]. the optimum activity was recorded at 90 days age. the combined effect of metakaolin and superplasticizer was clearer in the earlier ages and reached its peak performance at 28 days age with a ratio of 30% contribution to the compressive strength. thereafter, a reduced effect was observed. 3.4 splitting tensile strength figures 6 and 7 show the test results of splitting tensile strength at sample ages of 120 and 180 days. these figures showed increase in splitting tensile strength for the superplasticizer concrete mixes relative to that of the controlled mixes. this could be attributed to an increase in compressive strength of these mixes, resulting from the positive action of superplasticizer admixture with metakaolin. behaviour consistent with that of compressive strength was recorded for both test ages. when compared with the controlled concrete mixes, the percentage increases in the splitting tensile al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 153 strength of the superplasticizer concrete mixes containing 15% and 30% recycled glass at 120 days age were 9.4% and 11% respectively. the corresponding percentages at 180 days age were 7% and 21.3% respectively. bs en 1992-1-1[37] suggested the following expression to predict the splitting tensile strength of lightweight concrete according to its density and the characteristics of normal weight concrete. (5) (6) (7) where and are the splitting tensile strength of the light and normal weight concrete respectively in mpa ; is the compressive strength of normal weight concrete in mpa, and is the density of lightweight concrete in kg/m 3 . after statistical analysis had been performed, it was shown that equation (5) was unable to match the results obtained for splitting tensile strength in this study. this is because a reasonable r squared value for the nonlinear regression analysis could not be achieved. 4 conclusions the results of this study highlight the effect of superplasticizer admixture when used in conjunction with metakaolin and glass aggregate on the mechanical behaviour of expanded clay concrete. the main conclusions of this paper can be summarized as follows:  the superplasticizer admixture reduced the water content by up to 20%. however, the workability of the concrete mixes deteriorated with the use of superplasticizer.  an increase in the density values of the superplasticizer concretes was recorded compared with the controlled mixes, and the highest value was for the mix of 30% glass with 2% superplasticizer admixture for all test ages.  a significant increase in the compressive strength values was achieved when the superplasticizer admixture was used in conjunction with metakaolin, especially at earlier sample ages.  increases in compressive strength due to the pozzolanic effect of metakaolin continued longterm (180 days) for both control concrete mixes.  the contribution metakaolin and superplasticizer admixture to the compressive strength was clearer at the earlier stages and reached its peak performance at 28 days age with a ratio of 30%.  consistent positive improvements in splitting tensile strength to that in compression features were observed at both short and long-term behaviours. 5 references [1] palacios, m., et al., adsorption of superplasticizer admixture on alkali-activated slag pastes, cement and concrete research, 39: 670-677, 2009. [2] mollah, m., et al., a review of cement-superplasticizer interactions and their models, advance in cement research, 12, no.4, 153-161, 2000. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 154 [3] hsu, k., et al., effect of addition time of a superplasticizer on cement adsorption and concrete, cement and concrete composites, 21, 425-430, 1999. [4] neville, a., properties of concrete, pearson education limited, edinburgh: england 1-842, 2000. [5] mortimer, r., physical chemistry, redwood city, california: benjamin/cummings, 807809, 1993. [6] morin, v., et al., superplasticizer effects on setting and structuratio mechanisms of ultrahigh-performance concrete, cement and concrete research, 31: 63-71, 2001. [7] ramachandran, v., et al., concrete science, london, 151-153, 1981. [8] tung cl., chi sp. properties of architectural prepared with recycled glass with different particles sizes. materials and design 2011; in press. 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[19] dong o., et al. increasing mortar strength with the use of activated kaolin by products from paper industry. construction and building materials 2011; 25: 1537-1545. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 155 [20] paulo c., et al. effect of portuguese metakaolin on the hydraulic lime concrete using different curing conditions. construction and building materials 2010; 24: 71-78. [21] karoline am., arnaldo mp. effect of metakaolin’s finesses and content in self consolidating concrete. construction and building materials 2010; 24: 1529-1535. [22] k. ganesh , p. dinakar strength efficiency of metakaolin in concrete. structural concrete 2006; 7(1): 27-31. [23] m. frias the effect of metakaolin on the reaction products and microporosity in blended cement pastes submitted to long hydration time and high curing temperature. advance in cement research 2006; 18 (1):1-6. [24] j.m khatib, metakaolin concrete at a low water to binder ratio. construction and building materials 2008; 22: 1691-1700. [25] iraqi standard no(5), specifications of the portland cement, 1984. [26] bs en 12620, aggregate for concrete, british standards: 1-60, 2008. [27] http://www.plasmor.co.uk/html/company/expanded-clay; technical paper, 8-5r medium grade. [28] http://www.whitchem.co.uk/adhesives.htm; technical paper of metastar 501. [29] http://www.uk.graceconstruction.com/product.cfm?mode=c&id=25&did=1; technical paper for daracem sp6. [30] bs en 934-2, admixtures for concrete, mortar and grout, part 2: concrete admixtures – definitions, requirements, conformity, marking and labelling, british standards: 1-26, 2009. [31] bs en 12390-2, making and curing specimens for strength test, british standards: 1-12, 2009. [32] bs en 5075-3, concrete admixture, part 3: specifications for superplasticizer admixture, british standards: 1-16, 1985. [33] bs en 12350, testing fresh concrete, part 2: slump test, british standards: 1-12, 2009. [34] bs en 12390-7, testing hardened concrete, part 7: density of hardened concrete, british standards: 1-14, 2009. [35] bs en12390-3, testing hardened concrete, part 3: compressive strength of test specimens’ british standards: 1-22, (2009). [36] bs en 12390-6, testing hardened concrete, part 6: splitting tensile strength of test specimens, british standards: 1-14, 2009. http://www.plasmor.co.uk/html/company/expanded-clay http://www.whitchem.co.uk/adhesives.htm http://www.uk.graceconstruction.com/product.cfm?mode=c&id=25&did=1 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 156 [37] bs en 196-5, method of testing cement: part 5: pozzolanicity test for pozzolanic cement, british standards: 1-16, 2005. [38] wild, s., et al., a relative strength, pozzolanic activity and cement hydration in superplasticised metakaolin concrete, cement and concrete research, 26, no.10, 15371544, 1996. table (1): details of concrete mixes ingredient concrete mixes reference control mixes superplasticizer mixes 15% g+0% sp 30% g+0% sp 15% g+2% sp 30% g+2% sp o. p cement 392.07 352.84 352.84 352.84 352.84 metakaolin 0.00 39.20 39.20 39.20 39.20 natural sand 598 508.28 418.59 508.28 418.59 glass aggregate. 0.5-1 mm 0.00 43.46 86.93 43.46 86.93 glass aggregate. 1-2 mm 0.00 43.46 86.93 43.46 86.93 expanded clay 247.50 247.50 247.50 247.50 247.50 superplasticizer 0.00 0.00 0.00 7.05 7.05 w/c 0.45 0.45 0.45 0.36 0.36 table (2): calculated values of , , and for controlled and modified concrete mixes mix name age of test (%) r e fe re n c e m ix (0 % m k + 0 % s p ) 7 days 16.060 0.160 0.000 1.000 0.000 28 days 18.530 0.1853 0.000 1.000 0.000 90 days 19.930 0.1993 0.000 1.000 0.000 180 days 20.800 0.208 0.000 1.000 0.000 c o n tr o l m ix 1 5 % g la ss 1 0 % m k + 0 % s p 7 days 15.450 0.171 0.011 0.962 6.446 28 days 19.930 0.221 0.036 1.075 16.322 90 days 22.070 0.245 0.045 1.107 18.726 180 days 22.750 0.252 0.044 1.093 17.714 c o n tr o l m ix 3 0 % g la ss 1 0 % m k + 0 % s p 7 days 15.270 0.169 0.009 0.950 5.343 28 days 19.820 0.220 0.034 1.069 15.857 90 days 22.040 0.244 0.045 1.105 18.616 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 157 180 days 22.040 0.244 0.036 1.059 15.063 s u p e rp la st ic iz e r m ix 1 5 % g la ss 1 0 % m k + 2 % s p 7 days 18.105 0.205 0.045 1.127 21.939 28 days 22.835 0.259 0.074 1.232 28.590 90 days 22.940 0.260 0.061 1.151 23.546 180 days 22.640 0.257 0.049 1.088 19.151 s u p e rp la st ic iz e r m ix 3 0 % g la ss 1 0 % m k + 2 % s p 7 days 19.650 0.223 0.062 1.223 28.077 28 days 23.480 0.266 0.081 1.267 30.551 90 days 23.935 0.271 0.072 1.200 26.724 180 days 25.210 0.286 0.078 1.212 27.393 figure (1): the workability behaviour of various lightweight concrete mixes. 15% g+2% sp 15% g+0% sp 30% g+2% sp 30% g+0% sp slump 28 45 32 48 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 s lu m p m m al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 158 figure (2): the density of various lightweight concretes mixes. figure (3): compressive strength behaviour of various lightweight concrete mixes 1500 1540 1580 1620 1660 1700 0 50 100 150 200 d e n s it y k g /m 3 time days 30% g+2% sp 30% g +0% sp 15% g+2% sp 15% g+0% sp 14 17 20 23 26 0 50 100 150 200 c o m p re s s iv e s tr e n g th m p a age days 30% g+2% sp 15% g+ 2% sp 15% g+0% sp 30% g+0% sp al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 159 figure (4): satisfactory compression failure modes [35]: acracks failure, bdamage failure and c-explosive failure figure (5): contribution of pozzolanic effect and/or superplasticizer to the compressive strength of concrete mixes. 0 10 20 30 40 0 40 80 120 160 200 p % curing timedays 30% g+2% sp 15% g+2% sp 15%g+0% sp 30% g+0% sp al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 160 figure (6): splitting tensile strength of superplasticizer and controlled mixes at 120 days figure (7): splitting tensile strength of superplasticizer and controlled mixes at 180 days 15% g+2% sp 15% g+0% sp 30% g+2% sp 30% g+0% sp tensile st. 2.407 2.2 2.39 2.15 2.00 2.05 2.10 2.15 2.20 2.25 2.30 2.35 2.40 2.45 s p li tt in g t e n s il e s tr e n g th m p a 15% g+2% sp 15% g+0% sp 30% g+2% sp 30% g+0% sp tensile st. 2.4075 2.25 2.548 2.1 1.80 1.90 2.00 2.10 2.20 2.30 2.40 2.50 2.60 s p li tt in g t e n s il e s tr e n g th m p a article al-qadisiyah journal for engineering sciences 12 (2019) 232–239 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: dr.alsalih@gmail.com ( salih al shemry) https://doi.org/10.30772/qjes.v12i4.619 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. mass transfer coefficient study for release of naproxen from activated carbon for drug delivery application shahad f. hameed a, salih a. rushdi a* a department of chemical engineering, university of al-qadisiyah, al-qadisiyah, iraq. a r t i c l e i n f o article history: received 00 december 2019 received in revised form 00 january 2019 accepted 00 february 2019 keywords: activated carbon drug delivery loading mass transfer coefficient naproxen release a b s t r a c t activated carbon is a porous material that has a great character to be used for drug delivery system as a carrier. it is agreed that drug carriers maintain the concentration of drugs within the required range for a long period and undetermined toxicity resulting from the use of overdoses. they have the ability to direct the drug to the affected area, immunity, biophysics, and drug efficacy. activated carbon was used at two different particle sizes (0.6µm size with surface area 544.4704 m2/g and 11.042 nm size with surface area 985.6013m2/g ) and naproxen was used as a drug model. this research studied the effect of several parameters, including particle size (11.042 nm and 0.6µm), weight of drug to carrier weight ratio (0.5,1 and 1.5) on loading efficiency, and temperature (35, 37 and 39 ºc), time (1,3 and 5 hr), ph of the solution (1.5 and 6.5) on mass transfer coefficient in release drug. the result of experiments showed that maximum loading efficiency can be obtained when the particle size of activated carbon was in nano-size and the ratio of drug weight to ac weight was 1.5. the release process was studied by studying the mass transfer coefficient, the highest value of the mass transfer coefficient was obtained at the beginning of the unloading time, at temperature 37 ºc and solution in ph 6.5. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction in recent years, new ideas have been developed on pharmacokinetics control, pharmacodynamics, undetermined toxicity, immunity, biophysics, and drug efficiency. a smart drug delivery system (sdds) was the name of these strategies [1]. because of the development of new pharmaceutical molecules is costly and time-consuming, one alternative is to increase the effectiveness of older drugs by delivering them at a controlled rate and effectively targeting them. this strategy consists of transferring a specified amount of therapeutic agent for an extended period to a specific area in the body at a controlled manner [2], which symbolizes one of the key areas developed rapidly in the sciences in which chemical engineers and chemists contribute to the care of human health. it is one of the main objectives of the science of pharmacy, drug activity is endemic in the workplace and is http://qu.edu.iq/ https://doi.org/10.30772/qjes.v00i0 shahad f. hameed and salih a. rushdi /al-qadisiyah journal for engineering sciences 12 (2019) 232–239 233 necessary for improving the treatment of diseases [3], through selective accumulation in situ and less accumulation elsewhere, hence increasing the therapeutic value of the drug and reduce drug costs and take advantage of current treatment methods at a lower price. they also include less toxicity, enhanced efficacy [4], patient comfort, and compliance than conventional doses in addition to the possibility of using the medicine currently available [5]. the process of loading can be achieved through several steps, one of them is the principle of adsorption, which is defined as the collection of substances (usually ions or gases in the form of atoms or molecules) called absorbents materials on the surface of other porous solids material called adsorbents materials. adsorption occurs as a result of an imbalance of the molecular forces of the surfaces of liquids and solids, and there are two types of adsorption, physical and chemical [6]. here the loading process depends on physical adsorption (van der waals adsorption). the working force between the surfaces adsorbent and absorbed is the forces of van der waals, which are natural forces of attraction between the adsorbent, which is idle due to the electronic saturation of its atoms due to the bonds with which these atoms are connecting with ions or the molecules that adsorbed on the surface of atoms adjacent to the substance itself [7]. loading efficiency of drugs calculate by using this equation [15]. loading eff. = weight of the drug in a complex total weight of complex (1) the change in drug concentration over time is reliant upon three factors: the diffusion of the drug into or out of the system, the amount of drug leaving or entering the system due to bulk fluid flow and the generation or consumption of the drug within the system [8]. the diffusion of a drug is proportional to the concentration gradient. when there is a steep concentration gradient, such as when a drug delivery vehicle is placing in a fluid containing no drug, the diffusion occurs faster than when the concentration gradient is low, such as when the concentration outside of a delivery vehicle is near the concentration inside the delivery vehicle [1]. when the concentrations in one area are equal to concentrations in an adjacent area, there will be no diffusive exchange of the molecule between those areas. diffusion is also a function of a physical constant, the diffusion coefficient, that describes the inherent properties of the material a molecule is diffusing through in a dense material, such as bone, the diffusion coefficient of a molecule is lower than in a free liquid such as water. diffusion coefficients are related, among other factors, to the size of the molecule diffusing. large molecules will diffuse more slowly, have a lower diffusion coefficient, than smaller molecules [9]. solubility is the maximum quantity of a solute drug that can be dissolved in the solvent, while the solubility rate (dissolution) is the rate at which this solute dissolves in the solvent. according to brunner and nernst equation the disintegration of the drug in a medium is influencing by several factors such as solubility, wettability of the drug, the absorption conditions of the dissolved medium and the surface area of the drug [10, 13]. several strategies have been developed to modify the above factors to improve the solubility or solubility rate of drugs with poor water solubility; however, such techniques are often relating to limitations concerning poor stability and low drug loading. one of the many soluble enhancing techniques involves converting the crystalline drug into an amorphous state, because the rate of decomposition of the amorphous form is significantly better than the crystalline form, especially in high energy crystalline drugs [14]. the dissolution of solid drug suspended in solution is known to be controlled by the diffusion of this drug away from the solid surface of the undissolved material. starting with a mass balance equation to associate the dissolution result with a mass transfer coefficient then integrating it with boundary condition c=0 at t=0 𝒂𝒄𝒄𝒖𝒎𝒖𝒍𝒂𝒕𝒊𝒐𝒏 𝒐𝒇 𝒅𝒓𝒖𝒈 𝒊𝒏 𝒔𝒐𝒍𝒖𝒕𝒊𝒐𝒏 = 𝒕𝒐𝒕𝒂𝒍 𝒅𝒊𝒔𝒔𝒐𝒍𝒖𝒕𝒊𝒐𝒏 𝒓𝒂𝒕𝒆 𝑉 𝑑𝑐 𝑑𝑡 = 𝐴𝑗 (2) 𝑗 = 𝐴 𝐾 (𝑐𝑠𝑎𝑡 − 𝑐) (3) sup eq (3)in (2) 𝑉 𝑑𝑐 𝑑𝑡 = 𝐴 𝐾 (𝑐𝑠𝑎𝑡 − 𝑐) (4) rearrangement eq (4) 𝑑𝑐 𝑐𝑠𝑎𝑡−𝑐 = 𝐴 𝐾 𝑉 𝑑𝑡 (5) integrate eq (5) with boundary condition c=0 at t=0 − ln(𝑐𝑠𝑎𝑡 − 𝑐) = 𝐴 𝐾 𝑉 𝑡 + 𝐵 (6) compensating b.c. where b is integration constant 𝐵 = − ln 𝑐𝑠𝑎𝑡 (7) sub in eq (6) ln 𝑐𝑠𝑎𝑡 𝑐𝑠𝑎𝑡 − 𝑐 = 𝐴 𝐾 𝑉 𝑡 𝑜𝑟 𝑐 𝑐𝑠𝑎𝑡 = 1 − exp (− 𝐴 𝐾 𝑉 𝑡) ∴ 𝐾 = 𝑉 𝐴 𝑡 𝑙𝑛 𝑐𝑠𝑎𝑡 𝑐𝑠𝑎𝑡−𝑐 (8) nomenclature ac activated carbon cn carbon nanotubes sdds smart drug delivery systems df degree of freedom seq ss the sequential sum of squares eff. efficiency uv ultraviolet–visible epr enhanced permeability and retention w weight g grams sn signal to noise ratios hr hour csat saturation drug concentration at the solid surface of particle ibu ibuprofen d diffusion macro. macro particle size j molar flux rate of drug ml milliliter k overall mass transfer coefficient nano. nanoparticle size t time pa paracetamol a area of particle psi porous silicon c concentration of drug at the edge of the fluid diffusion layer in the bulk solution cn carbon nanotubes 234 shahad f. hameed and salih a. rushdi /al-qadisiyah journal for engineering sciences 12 (2019) 232–239 many previous studies have been used carbon as a drug carrier. activated carbon(ac) was used as a drug carrier while pa and ibu were used as drugs that were loaded into ac at 44.4 % and 20.7 % loading efficiency respectively. related studies suggested that within 10 min drug release for two pa/ac and ibu/ac complexes was completed in the presence of sodium phosphate buffer (ph 5.8) [15]. ac is using in drug delivery research because of its high internal volume, its ability to cross the cell, membrane easily, small size, surface area increases to volume ratio, and its capability to include chemicals and high drug loading, among other types that making it's helpful for cancer treatment [16]. cancer is one of the most difficult diseases of new times because its treatment includes distinguishing infected cells from normal healthy cells. here, carbon nanotubes(cn) plays a vital role because of a phenomena such as epr which leading cn types to distinguish normal cells from infected cells, the major advantage in cancer treatment [17], hence helping in developing an effective, inexpensive, and safe delivery of oral medication, therefore, carbon materials were used in biomedical applications for several decades [16]. ac is a space surrounded by carbon atoms, having other names like active carbon, activated charcoal, or activated coal. this space (porous) has zero electron density and possesses intense van der waals forces, which are responsible for its exceptional ability to adsorb chemical species. these forces depend on the distance between carbon atoms and the bond arrangement of bonds between carbon and hetero-atoms [17]. one of the first applications is the use of activated carbon to build synthetic heart valves and in blood, embolisms to treat external and internal poisoning with different causes. applications of new carbon nanotubes depend on their mechanical, physical, structural, and chemical characteristics, which are often superior to other materials. this benefit is propped by the truth that many carbon materials have perfect biological compatibility and could utilize in direct connection with human blood and tissues. the biological compatibility phenomenon is too complex, and its main factors are not yet fully comprehended, yet it is called to be related to protein absorption on the surface of materials exposed to the human body [18]. mesoporous silicon microparticles (psi) were used as a pharmaceutical carrier, these mesoporous silicon particles produced by using thermal oxidation or thermal carbonization to obtain suitable surfaces for the ability to administer the oral drug. five typical drugs ibuprofen, ranitidine, furosemide, griseofulvin, and antipyrine were used. the loading efficiency obtained was between 9% and 45% with (psi) mesoporous silicon molecules, in addition to the effects related to the stability of the particles in the presence of organic or aqueous solvents. the properties of the surface, loading solution and the chemical nature of the drug are found to be critical to the loading process. the release rate of drug-loaded from particles of psi depends on the properties and solubility behavior of the drug materials. when the rate of drug dissolution (unloading drug) was high, microscopic particles caused the release delay. however, with poor drug dissolution, loading into microscopic particles improves solubility. in addition, the ph dependency of the dissolving process decreased when the substance of the drug-loaded into microscopic particles [19]. the main objective of this work is to obtain more release naproxen control by loading naproxen on carbon molecules and study the change of loading efficiency with the change of the size and quantity of activated carbon carrier relative to the amount of the drug. in addition, the effect of the mentioned later factors on the release process was studied through the mass transfer coefficient. 2. materials and experimental procedure 2.1. materials  two types of activated carbon with different particles size were used, the first was macro particle size 0.6µ with surface area 544.4704 m2/g purchased from sigma aldrich and the second was nanoparticle size 11.042 nm with surface area 985.6013m2/g purchased from lab shop.  naproxen from cayman company.  ethanol alcohol c2h5oh (purity 99.9%) with density 789 (kg/m 3).  methanol alcohol ch3oh (purity 99 %)with density 792 (kg/m 3).  hydrochloric acid hcl with normality of 11.5 n (mole/l).  injection water 100% of sterile water for injection from a local source.  silica gel from a local source. 2.2. experimental procedure 2.2.1. loading drug stage sample of drug/ac was prepared by dissolve naproxen in ethanol according to saturation solubility 100 mg/ml. then 5 g activated carbon was added to the naproxen ethanol solution as shown in table 1. the solution was mixed by a magnetic stirrer for 24 hours at room temperature then the solution was subjected to an initial drying by buchner funnel, here the material was weighed, and the volume of the remaining liquid was measured. dry the remaining material in an oven for 4 hours at a temperature of 40-degree centigrade, and the samples were weighed. finally the substance kept in sealed cans inside a container containing silica gel. the concentration of drugs in the solution on the buchner funnel was measured by uv spectrometer. this concentration will be multiplied by the volume of the solution to determine the weight of the unloaded drug [15]. loading efficiency calculated by use eq (1) 2.2.2. calculation the mass transfer coefficient in this work, the experiments were designed by taguchi (licensing 17.1.0 2013). three factors were considered; temperature, ph of solution, and time. ph of solution was studied at two-levels (1.5 and 6.5),temperature at three-levels (35,37 and 39 ºc) and time at three-levels(1,3,5hr). the mass transfer coefficient was calculated by using eq (7) through 18 run number of experiments. mass transfer coefficient calculated depending on the concentration of drugs at different times to determine this concentration of complex by taking 100 ml from two solutions (ph 1.5 prepared from 99% water injected and 1% hydrochloric acid and ph 6.5 prepared from 99 % injection and 1% methanol) taken in 6 beakers then added (87.71) mg from the naproxen /macro ac sample and (84.74) mg from the naproxen/nano ac sample to glasses these amount taken according to the standard dosage weights of 500 mg for naproxen and loading eff. for macro and nano activated carbon. then put the beakers in shaking water bath sate the temperature (35,37,39) co and 50 shakings per minute[20], then calculate the concentration for 6 hour time by uv spectrometer. shahad f. hameed and salih a. rushdi /al-qadisiyah journal for engineering sciences 12 (2019) 232–239 235 0 20 40 60 80 0 0.5 1 1.5 2 lo a d in g e ff ic in cy w drug/w ac naproxen macro particle nano particle 3. 3. results and discussions 3.1. naproxen loading results fig. 1. show that the loading efficiency slightly increased when the ac particle size decreases from macro to nano-size at any w drug / w ac while a maximum loading efficiency was achieved at 1.5/1 w drug / w ac ratio for ac nanoparticle during the loading. figure 1. loading efficiency behaviour for naproxen drug as shown in table 1. there is little difference between the quantities produced and the actual quantities used. this difference was happened because of the adhesion of some of the mixture in the equipment used during the experiment, including the filter papers. loading efficiency was reached a maximum of around 24 hours of incubation, after which the loading efficiency no longer increases and in some cases, is even lowered. 3.2. naproxen unloading results naproxen release from the complex was incompleted due to the poor wettability of carbon particles which may increase or decrease the emission period leading to the stronger effect of ac porosity on solubility profiles. fig. 2. shows that when ph=6.5 and at 6 hours, 100% drug release occurred when the drug pure without carbon and ~80% release from macro activated carbon while the best result (70% release ) was obtained from nano activated carbon and showed that the release was controlled at drug/nanoac complex. when ph=1.5, fig. 3. shows that at 6 hours ~100% drug release when the drug pure without carbon and 80 % release from macro activated carbon while the best result release > 70 % was obtained from nano-activated carbon. the comparative between these figures shows that at ph 6.5 the drug release was more control. table 1. drug loading step result for naproxen loading figure 2. naproxen release pattern in ph6.5 solutions figure 3. naproxen release pattern in ph1.5 solutions the mass transfer coefficient values were obtained from using equation (3) that given the saturated concentrations of 0.5 mg/ml for naproxen. as shown in figs. 4.7 there is some similarity in the mass transfer coefficient variation with time and the coefficient increases in the dissolution medium from zero to the highest value and then begins to decline gradually until it reaches a stage that is controlled slightly less with time, this was due to the loading process. eff.% w drug loading (g) w drug unload. (g) cons. drug (g/ml)×102 vol. of sol. remain (ml) w of complex after dray w of complex before dray vol. of ethanol (ml) 𝑊(𝑑𝑟𝑢𝑔)𝑔𝑚 𝑊(𝑑𝑟𝑢𝑔)𝑔𝑚 type of ac drugs 30 2.126 0.374 3.74 10 6.901 10.714 25 2.5/5 macro naproxen 46 4.124 0.876 3.13 28 8.896 17.316 50 5/5 57 6.454 1.046 2.49 42 11.239 20.836 75 7.5/5 30 2.276 0.224 3.2 7 7.458 14.782 25 2.5/5 nano 48 4.651 0.349 3.17 11 9.393 21.615 50 5/5 59 6.837 0.663 2.65 25 11.769 29.977 75 7.5/5 0 20 40 60 80 100 120 0 1 2 3 4 5 6 7 8 re a ls e d ru g % time hr ph 1.5 pure drug drug/macro. ac complex drug/nano. ac complex 0 20 40 60 80 100 120 0 1 2 3 4 5 6 7 re a ls e d ru g % time hr ph 6.5 pure drug drug/macro. ac complex drug nano. ac complex 236 shahad f. hameed and salih a. rushdi /al-qadisiyah journal for engineering sciences 12 (2019) 232–239 figure 4. mass transfer coefficient variation with time for naproxen/macro ac sample in ph 6.5 figure 5. mass transfer coefficient variation with time for naproxen/macro ac sample in ph 1.5 figure 6. mass transfer coefficient variation with time for naproxen/nano. ac sample in ph 6.5 figure 7. mass transfer coefficient variation with time for naproxen/nano. ac sample in ph 1.5 the results of the statistical analysis using taguchi program show the effect of the three variables on the mass transfer coefficient as follows: -naproxen/macro.ac complex, the most effective parameter was time with present of contribution (69.22%), while the least effect is ph solution with present of contribution (0.12%). -naproxen/nano.ac complex, the most effective parameter was time with present of contribution (62.78%), while the least effect is ph solution with present of contribution (0.97%). note from the table 2. that all coefficient for a factor is significant (r_sq value > 0.9), so could conclude that the relation between the response and a factor relies on the factors in the expression. the coefficient contribution explains the direction and size of the relation between the variable of response and factors in the model, so the relative strength of each factor represents the absolute value of this coefficient. the coefficient minitab number determines for a factor was the level number minus one. the regression equations for mass transfer coefficient (multiple linear regression model) is given by: y = b0 + b1x1i + b2x2i + · · · + bkxki where y is the observed response(mass transfer coefficient cm/hr) to the values x1i, x2i, . . . , xki of the k independent variables x1, x2, . . . , xk. three factor (x1 temp. ,x2 time and x3 ph of solution) ,i number of level (three level for x1 and x2 (35co, 37 co, 39 co, 1hr, 3 hr and 5 hr)sequentially and two level for x3(1.5 and 6.5) . figs. 8 and 9 shows the main effect plot. there is no significant effect, if the line was horizontal in the sense that the effect of all levels of factors on response value was in the same way, and the average of response was the same in all levels of factors .there is a significant effect, if the line was not horizontal in the sense that the effect of the levels was different from one factor to another. the larger the variety of plots in the vertical axis, in other words the drawn points were not parallel to the x-axis, the greater the value of the main effect. the relative quantity of effect of factors can be compared by comparing slope lines. 0 0.00005 0.0001 0.00015 0.0002 0.00025 0.0003 0.00035 0.0004 0.00045 0 1 2 3 4 5 6 7 m a s s t r a n s f e r c o e f f ic ie n t c m /h r time hr tem.39c tem.37c tem.35c 0 0.0001 0.0002 0.0003 0.0004 0.0005 0 1 2 3 4 5 6 7 m a s s t r a n s f e r c o e f f ic ie n t cm /h r time hr tem.39c tem.37c tem.35c 0 0.00005 0.0001 0.00015 0.0002 0.00025 0 1 2 3 4 5 6 7 m a s s t r a n s f e r c o e f f ic ie n t cm /h r time hr tem.39c tem.37c 0 0.00005 0.0001 0.00015 0.0002 0 1 2 3 4 5 6 7 m a s s t r a n s f e r c o e f f ic ie n t c m /h r time hr tem.39c tem.37c tem.35c shahad f. hameed and salih a. rushdi /al-qadisiyah journal for engineering sciences 12 (2019) 232–239 237 table 2. result of statistical analysis for mass transfer coefficient study table 3. regression equations regression equations samples y= 0.000193 0.000053 x11 + 0.000080 x12 -0.000028 x13 + 0.000131 x21 0.000046 x22 -0.000085 x23 0.000004 x31 + 0.000004 x32 naproxen/ macro.ac y = 0.000090 0.000006 x11+ 0.000034 x12 -0.000028 x13 + 0.000053 x21 0.000016 x22 -0.000037 x23 0.000005 x31 + 0.000005 x32 naproxen/ nano.ac figs. 10 and 11 show the residuals plot. the residuals versus fits plot, which has the independent variable on the horizontal (x) axis and the remains on the vertical (y) axis. this plot explains a fairly irregular pattern all residual points above the line are positive, the points down are negative. this irregular pattern refers that a linear model gives the data a decent fit, and indicating a good fit for a linear model. residuals against order plot show the residues values in the vertical axis versus the order of experiments sequence in which the data were collected. it was used to find out whether the residues values were independent of each other from one experiment to another. the remains were randomly located around the midline patterns, where dots were close together which may be indicated that these may be not independent values [21]. residuals plot histogram shows whether the residuals values are normally distributed, i.e., to determine whether the data is skewed or contains outliers. asymmetric graph around zero in the form of a bell meaning that points are distributed evenly around zero which indicates that the assumption of normal state is likely to be correct. a long tail in one direction indicates deviation, and the tape that was away from the other bars may point to an outlier. extreme tops can describe as extremely low or too high values that are not near any other data points [22]. the plot of normal probability for a residual showed the residuals in x-axis versus expected values for their in y-axis. whenever the distribution of points around the line was regular (the plot nearly follows an alignment line), this indicates that the equations represent the system more precisely and verify the assumption of distributed normally to the residuals, little points located far from the line means an outliers distribution [23]. figure 8. main effects plot for signal to noise ratio naproxen/macro ac complex figure 9. main effects plot for signal to noise ratio naproxen/nano ac complex r_sq % p_value f_value contribution seq ss df source complex 95.34 0.589 0.31 0.12% 0.00 1 ph naproxen/ macro.ac 0.000 89.17 69.22% 0.00 2 time(hr) 0.000 33.5 26.01% 0.00 2 tem(co) ----------4.66% 0.00 12 error ----------100% 0.00 17 total 90.97 0.280 1.28 0.97% 0.00 1 ph naproxen/ nano.ac 0.000 41.7 62.78% 0.00 2 time(hr) 0.000 18.09 27.23% 0.00 2 tem(co) ----------9.03% 0.00 12 error ----------100% 0.00 17 total 238 shahad f. hameed and salih a. rushdi /al-qadisiyah journal for engineering sciences 12 (2019) 232–239 figure 10. residual plots for naproxen /macro. ac complex figure 11. residual plots for naproxen /nano ac complex 4. conclusions loading of naproxen was successfully achieved in activated carbon pores. the maximum loading efficiency for the drug was 59% when the activated carbon molecular in nanoparticle size and when the weight ratio of drug to activated carbon more than 1. furthermore, the mass transfer in the drug delivery process was more controlled when the activated carbon was in nanoparticle size. the best temperature given the maximum mass transfer coefficient was 37ºc, and this corresponds to the heat of the human body. also the difference in ph of solution values was no strong effected on release drugs this is because all the solutions used were acidic corresponds to the middle of the stomach and intestines of the human. references [1] rossi, f., perale, g. and masi, m., controlled drug delivery systems: towards new frontiers in patient care. springer international publishing, (2016). [2] sengupta, a. intracellular drug delivery using laser activated carbon nanoparticles (doctoral dissertation, georgia institute of technology) , (2014). [3] s. chatterjeefda perspective on continuous manufacturing, ifpac annu. meet. , (2012). [4] m. krumme, control strategies for continuous processes, talk at 10th world meeting on pharmaceutics, biopharmaceutics and pharmaceutical technology, glasgow (uk), (2016) april 7th . [5] kushwaha, s.k.s., ghoshal, s., rai, a.k. and singh, s. carbon nanotubes as a novel drug delivery system for anticancer therapy: a review. brazilian journal of pharmaceutical sciences, 49(4), (2013)pp.629-643. [6] da̧ browski, a.,adsorption from theory to practice. advances in colloid and interface science, 93(1–3), (2001) pp.135–224. [7] newcombe, g. chapter twentysix adsorption from aqueous solutions: water purification. in e. j. bottani & j. m. d. tascón, eds. adsorption by carbons. amsterdam: elsevier, (2008)pp. 679–709. [8] truskey ga, yuan f, katz df., transport phenomena in biological systems. upper saddle river, new jersey:pearson education,inc( 2004). [9] foy bd and blake j. diffusion of paramagnetically labeled proteins in cartilage: enhancement of the 1-d nmr imaging technique. journal of magnetic resonance imaging ; (2001),148:126-34. [10] banker, g.s., siepmann, j. and rhodes, c., modern pharmaceutics, fourth edition, crc press, (2012). [11] leuner, c. and dressman, j. improving drug solubility for oral delivery using solid dispersions. european journal of pharmaceutics and biopharmaceutics : official journal of arbeitsgemeinschaft für pharmazeutische verfahrenstechnik e.v, 50(1), (2000), pp.47–60. [12] limnell, t., surface chemistry and pore size affect carrier properties of mesoporous silicon microparticles. international journal of pharmaceutics, 343(1–2), (2007). pp.141–147. [13] smith, b.t., physical pharmacy remington., pharmaceutical press(2016). [14] salonen, j.,mesoporous silicon in drug delivery applications. journal of pharmaceutical sciences, 97(2),( 2008),pp.632–653. [15] miriyala, n., ouyang, d., perrie, y., lowry, d. and kirby, d.j. activated carbon as a carrier for amorphous drug delivery: effect of drug characteristics and carrier wettability. european journal of pharmaceutics and biopharmaceutics, 115, (2017) pp.197-205. [16] snyder, s.a., adham, s., redding, a.m., cannon, f.s., decarolis, j., oppenheimer, j., et al. role of membranes and activated carbon in the removal of endocrine disruptors and pharmaceuticals. desalination,(2007). 202, 156-181 . [17] marsh, h., reinoso, f.r. activated carbon elsevier, (2006). [18] kim, s.d., cho, j., kim, i.s., vanderford, b.j., snyder, s.a. occurrence and removal of pharmaceuticals and endocrine disruptors in south korean surface, drinking, and waste waters. water research. : (2007) , 41, 1013-1021 [19] salonen, j., laitinen, l., kaukonen, a.m., tuura, j., björkqvist, m., heikkilä, t., vähä-heikkilä, k., hirvonen, j. and lehto, v.p. mesoporous silicon microparticles for oral drug delivery: loading and release of five model drugs. journal of controlled release, 108(2-3), ., (2005),pp.362-374. [20] ghoshal, s., kushwaha, s.k.s., srivastava, m. and tiwari, p.,drug loading and release from functionalized multiwalled carbon nanotubes loaded with 6-mercaptopurine using incipient wetness impregnation method. am j adv drug del, 2(2),( 2014),pp.213-223. [21] ranganath, m. s., mishra rs vipin, and nikhil prateek. "optimization of surface roughness in cnc turning of aluminium 6061 using taguchi techniques." international journal of modern engineering research 5 (2015): 42-50. [22] bhattacharya, anirban, santanu das, p. majumder, and ajay batish. "estimating the effect of cutting parameters on surface finish and power consumption during high speed machining of aisi 1045 steel using taguchi design and anova." production engineering 3, no. 1 (2009): 31-40. [23] olabi, a. g., g. casalino, k. y. benyounis, and m. s. j. hashmi. "an ann and taguchi algorithms integrated approach to the optimization of co2 laser welding." advances in engineering software 37, no. 10 (2006): 643-648. article al-qadisiyah journal for engineering sciences 12 (2019) 214–219 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohaned.ganem26@gmail.com (muhaned g. al-khuzaie) https://doi.org/10.30772/qjes.v12i4.638 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. assessment of dowel bars performance in concrete pavement containing crumb rubber of tires muhaned g. al-khuzaie a*, basim h. al-humeidawi b, ra'id f. al-sa'idi c a highways and transportation department, college of engineering, mustansiriyah university, baghdad province, iraq b roads and transport department, college of engineering, university of al-qadisiyah, al-diwaniyah province, iraq c civil engineering department, college of engineering, mustansiriyah university, baghdad province, iraq a r t i c l e i n f o article history: received 19 september 2019 received in revised form 20 november 2019 accepted 26 november 2019 keywords: steel dowel bars concrete pavement crumb rubber pullout test joints a b s t r a c t solid waste management is one of the big challenges facing most countries around the world. reusing these wastes in construction project represent one of the most efficient ways to consume these wastes and reduces the demand on natural sources. the crumb rubber (cr) of tires is a source of a huge amount of solid waste that can be reused in construction projects such as paving of roads. the current research presents an experimental investigation for the dowel bars performance in rubberized concrete pavement. the research involves conducted pullout tests for dowel bars cast in concrete pavement contains a different percentage of cr particle (2%, 4%, and 6% of total aggregate) as partial or total replacement to aggregate on sieves no. 16 and no. 50. four cases of dowel bars surface were investigated. the results of the study showed that adding cr particles to concrete can significantly reduce the bond between the dowel bars and surrounding concrete pavement which allows for more free movement of dowel bars and reduce joint lockup. the use of treated cr by naoh solution with standard dowel bars (epoxy coated lubricant steel dowels) can give a superior reduction in pullout load. the reductions were 45%, 66%, and 83% in pullout load for the percentages of 2%, 4%, and 6% crumb rubber respectively compared with the reference mix. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction cement concrete pavement is one of the largely used pavement in most counties of the word during the last century and up to now. the concrete pavement is built as series of neighboring slabs separated by joints or cracks. these joints are usually classifying to longitudinal and transverse joints according to the direction of construction. the joints are mainly responsible for releasing the stresses developed at the slabs and control the initiation of cracks[1]. the traffic loads are distributed between the adjacent slabs using aggregate interlock or dowel bars. since the aggregate interlock is active for the very narrow cracks of less than 1 mm, the dowel bars are the main mechanism used to transfer the load between the adjacent slabs [1-3]. the proper use of dowel bars in transverse joints of concrete pavement can significantly reduce the distress of concrete pavement. these stresses involve joint lockup, faulting, pumping, and mid-span cracks [4]. therefore, proper design and construction of these dowels mean better load transfer across these joints and less distresses. as a result, the dowel bars can be considered as a very important part of concrete due to its role in pavement structure. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 215 the rounded smooth steel dowels are the most convenient devices that used in transferring traffic loads across the transverse joints of rigid pavements especially when the pavement carries heavy traffic load and that joint opening is greater than 1 mm [5]. dowel bars are usually coated with corrosion resistant material and painted with smooth lubricant (or covered with plastic sleeve) to reduce bond with surrounding concrete in order to function properly. many studies have been carried out in the past to evaluate the performance of dowel bars across the transfer joints of the concrete pavement [6-9]. most of these studies were focused on the most identification of the problems with the performance of the steel dowel bars and trying to overcome these problems. other studies were investigated different alternative materials either to overcome the corrosion problem and related joint lockup or to upgrade dowel bars performance and consequently allows for free movement of slabs during expansion and contraction and prevent joint lockup [10-12]. the elliptical dowels and gfrp dowels are used in rigid pavement to determine whether they are a viable alternative to round steel dowels in highway joints [11]. the results of this study show that elliptically shaped dowels reduce bearing stresses at the dowel– concrete interface. the study also shows that gfrp dowels have load transfer capacities nearly as large as the steel and stainless-steel dowels studied. however, the deflections measured for the elliptical dowels and gfrp dowels were greater than those for round steel dowels. another study evaluates fiber reinforced polymer (frp) dowel bars as load transferring devices in jointed plain concrete pavement (jpcp) under hs25 static and fatigue loads and compares their response with jpcp consisting of steel dowels [12]. they found good results for (frp) in maximum bending deflection, relative deflection (rd), and bearing stress of dowels in addition to its long-term performance. another study focused on the evaluation of the load-deflection response of gfrp dowels using a scaled model of pavement slabs showed that the 38 mm gfrp dowels perform better in terms of deflection response compared to the 25 mm steel dowels [13]. also, it was observed that the relative deflection (rd) is more sensitive to the changes in the joint width rather than the concrete strength. most of these studies were dealing with preventing or reducing joint lockup by changing the dowel bars material. the current research focused on adding crumb rubber (cr) particles to the concrete pavement as a partial replacement for fine aggregate to reduce the bond between the dowel bars and surrounding concrete and reduce or prevent joint lockup. this was achieved by conducting pullout test for dowel bars cast in rubberized concrete pavement. 2. test methodology the test included pulling-out one aligned dowel bar from a concrete block to assess the dowel-concrete interaction in the presence of crumb tire rubber within the concrete. the concrete block was cast with dimensions of (200 × 200 × 350) mm, while the steel dowel dimensions were 25 mm for the diameter and 458 mm for the length with half of it embedded in concrete as recommended by aashto 1993 guideline [2]. four cases of dowel bars surface were examined as uncoated un-lubricant dowel, uncoated lubricant dowel, epoxy-coated un-lubricant dowel, and epoxy-coated lubricant dowel. 3. materials 3.1. concrete the concrete mix design was carried out according to aci 2002 [14] to satisfy the requirement of concrete compressive strength of rigid pavement (30 mpa for cube) as per scrb [15]. all the variables that have been adopted in the design of concrete mix were determined laboratory. the slump for rigid pavement according to aci code 211.91 [16] ranging from (2.5 -7.5) cm and according to scrb [15] from (0-5) cm, in the design of concrete mix, it was taken as 5 cm. the slump concrete was tested according to astm c143/c143m [17] for all cases of rubberized concrete mixes. the results of mix design for 1m3 are found in the table (1). table 1 concrete mix proportions materials weight in kg water 193 cement 395 gravel 1149 sand 792 3.2. epoxy coated steel dowel bars dowel bars used in this study were manufactured from mild steel grade 60 with minimum tensile strength of 90 mpa and minimum yield strength of 60 mpa as recommended by astm a615 / a615m – 09[18]. to ensure that the tensile strength is satisfied with the minimum requirement mentioned in the above standard, a test of tensile strength of the dowel bar was done according to astm a615 / a615m – 09. the obtained tensile strength was 235.5 mpa and the yield strength was 150 mpa which are more than the required tensile and yield strengths. figure (2) shows the stressstrain relationship of the steel dowel bar. the epoxy coating used in this research was sikagard – 62 which is a twopart epoxy protective coating a and b. the mixing ratio between the two parts is 3.75 from a to 1.25 from b (3.75: 1.25 ) as recommended by its datasheet. the epoxy was manufactured to satisfy british standard bs 6920 [19]. many researchers coated the dowel bars manually, however, that may produce not smooth surface and not equal thickness for all dowel but it can provide adequate corrosion resistance for dowel bars. the epoxy properties obtained from sika company as shown in the table (2). figure (1) shows the steel dowel bar after coating with epoxy. table 2 properties of epoxy coating. property magnitude property density 1.35 ± 0.05 kg/l density thermal expansion coefficient (α) 7.5 x10^ (-5) [α = m/m/ °c] thermal expansion coefficient (α) bond strength with concrete 3.5 n/mm² bond strength fig. 1 coated and uncoated steel dowel bars 216 m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 dowel bar should be covered with a light layer of grease or oil to prevent or reduce bonding between dowel and the surrounding concrete as recommended in aashto [2]. in this research, the light oil sae 10 was used to lubricant the dowel bar, since covering dowel bars with grease may cause looseness (gap) in the surrounding concrete of dowel bar which consequently reduces transferring of load and cause joint failure. fig. 2 stress-strain relationship of steel dowel bar 3.3. crumb rubber the cr that used in the research was obtained from babylon tires factory in iraq. three sizes of cr particles were used in experimental work, which was retained on the sieve no.16 (1.18 mm), no.50 (0.3 mm), and sieve no.100 (0.15 mm) as shown in figure (3). according to a previous study by the authors, the replacement was conducted for particles retained on sieve no. 16 and no.50. the physical and chemical properties of cr are presented in table (3) as obtained from babylon tires factory. fig. 1 crumb rubber particles: (a) retained on sieve no. 16, (b) retained on sieve no. 50, (c) retained on sieve no. 100 table 3 -chemical and physical properties of crumb rubber chemical composition physical properties rubber hydrocarbon content % physical properties test result rubber hydro carbon (sbr) 48% density 0.95 g/cm3 carbon black 31% ultimate tensile strength 9 mpa acetone extract 15% elongation at break 150% ash 2% hardness shore a 64 residue chemical balance 4% the cr was treated using sodium hydroxide (naoh). it is a solid white composite compound and it dissolves easily in water and is an alkaline solution. the naoh is also known as caustic soda because it is a very strong alkaline material, therefore, it is used in many industries and sterilization processes. several research works that dealt with cr used naoh solution to eliminate the zinc stearate. zinc stearate is formed during the production of tires during the uses of stearic acid zinc as a lubricant, anti-adherent, and use as activating agent of vulcanization urge medium [20]. as mentioned above the chemical treatment of cr was done by naoh solution, it’s very important method for improving the adhesion between cement and crumb rubber. naoh solution is the most efficient method to remove the zinc stearate (zinc salts) which appears as layers on concrete samples. these salts are composed of the crumb rubber surface during the tire manufacturing process [21]. naoh solution is a strong base solution that has erosion effect because of its high alkalinity, so this solution will scratch crumb rubber surface during mixing process this process makes the surface of crumb rubber more rough and lead to significant improvement of the adhesion between cement and crumb rubber particles [22]. the concentration of naoh solution used in this research was 10% and obtained by adding 100 gm of naoh particles to 1 litter of water. the treatment of cr involved washing the cr by water, then submerging the crumb rubber particles for 30 min. in a container having naoh solution. the ph level is raised and become alkaline base and finally washing crumb rubber particles by water until its ph became neutral. the washed crumb rubber then left exposed to air until it becomes dry. 4. results and discussion dowel bars are usually coated with epoxy to protect from corrosion and helping the horizontal movement of them. this coating may knock during installing and casting which causes corrosion and premature failure. the wearing of epoxy coated may cause rougher surface even in the presence of lubricant or plastic sleeve and consequently increase the friction between dowel bar and surrounding concrete, and obstruct free movement of the slab. in this study, cr was added to the concrete mix to improve the performance of concrete and reduce the bond between dowel and concrete pavement by converting the concrete from a brittle to a relatively ductile material without affecting its mechanical properties and load transfer efficiency of dowel bar. this was carried out by investigation of the bondslip behavior of dowel bars by using pullout test technique. four cases of dowel bars surface were also investigated as uncoated un-lubricated dowel bars, epoxy-coated un-lubricated dowel bars, uncoated lubricant dowel bars and epoxy-coated lubricant dowel bars. all results of pullout test are shown in table (4). figure (4) shows the pullout test sample at the testing machine. sixteen parameters were included in the testing program as shown in the testing matrix in table (4). table 4 -results of pullout test (kn) % replacement of cr particles 0 % 2 % 4 % 6 % uncoated dowel unlubricated 77 58 47 35 coated dowel 96 53 42 30 uncoated lubricant 52 37 34 19 coated lubricant 29 16 10 5 28 days compressive strength 39 36 33 28 fig. 4 pullout test sample at the testing machine. m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 217 4.1. effect of cr content the general achievement which can be observed from table (4), that the cr has greatly reduced the pullout value of the dowel bar and augmenting the free movement of the slab. from that table it can be observed that in case of uncoated un-lubricated dowel, the adding of 2% cr particles reduces pullout value by 24.6 % compared with a reference mix and when adding 4% cr particles the pullout value reduces by 38.9% compared with the reference mix. this reduction significantly increased by adding 6% cr particles in which the pullout load decreased by 54.5% compared with the reference mix. the reason for this decrease is the effect of cr particles which transformed the concrete from a brittle material into elastic material leading to a good separation between the dowel bar and the concrete. figure (5) shows the bond-slip behaviour of the four cases of the uncoated unlubricated dowel bar. all values of these curves gradually decrease as the percentage of rubber increases due to the presence of this material (cr) which reduced the brittleness of the concrete. fig. 5 load-displacement curves for the case of uncoated unlubricated dowel bars. 4.2. effect of epoxy coating of dowel in addition to protection against corrosion the epoxy, coating can play a vital role in reducing the bond between dowel bar and concrete. the experimental results showed that the coating of the dowel bar with epoxy can reduce the bond with rubberized concrete mixes for all rubber percentages. the pullout loads decrease by 9%, 11%, and 14 % compared with that of an un-coated dowel for samples containing 2%, 4%, and 6% cr respectively (see table (4)). in the case of the sample which has zero percentage of crumb rubber, the results showed inconsistent behavior compared with all other samples because the epoxy may not always provide good separation between the dowel bar and the concrete [23]. this doubtful performance may be attributed to the way of dowel bars coating. the manual coating of dowel bars may affect the results due to changing coating thickness or irregularities of surface, however, the general trend can be observed from the other samples. the epoxy coating is milling the very small holes and irregularities of the dowel bar surface so as reduce the friction between dowel bars and surrounding concrete and reduce the pullout load. moreover, it acts as a separation layer between the dowel bar and concrete. figure (6) shows the bond-slip behavior of the four investigated cases of epoxy coated unlubricated dowel bars. the curve for 0% does not behave like the rest of the curves because in this case there is no effect of crumb rubber unlike the rest of curves where we find the effect of crumb rubber and epoxy together. fig. 6 load-displacement curves for the case of coated unlubricated dowel bars for different percentages of cr. 4.3. effect of lubricant on uncoated dowel the lubricant of dowel bars is significantly reducing the pullout load. this reduction is increased by increasing the percentage of crumb rubber. the percentages of reduction are 32.5%, 34.5%, 27.6%, and 46% compared with uncoated un-lubricant samples containing 0%, 2%, 4%, and 6% cr respectively (see table (4)). this reduction is higher compared with the specimens containing coated dowel un-lubricant. this behavior is due to that the lubricant can generate a separation layer between the concrete and dowel, and reduce the growth of bond during the casting process. moreover, the coating is still necessary to protect dowel bars against corrosion and relatively decreasing the bond with concrete. figure (7) shows the bond-slip behavior of the cases of uncoated lubricant dowel bars for different percentages of rubbers. in this figure we see values lower than figure 6, but we cannot work without the epoxy for the previous reason. fig. 7 load-displacement curves for the case of uncoated lubricated dowel bars for different percentages of rubbers. 4.4. effect of greasing (lubricant) and coating of dowel the best results of the pullout test were obtained in the case of epoxycoated lubricant dowel bars as the least pullout loads were recorded. even the use of epoxy coated lubricant dowel bars are common, the use of these dowels with rubberized concrete pavement can significantly reduce the pullout load. the pullout loads were decreased by 45%, 66%, and 83% for 0 20 40 60 80 100 0 2 4 6 8 10 12 14 16 f o rc e [ k n ] displacement [mm] 0 % crumb rubber 2 % crumb rubber 4% crumb rubber 6 % crumb rubber 0 20 40 60 80 100 0 2 4 6 8 10 12 14 16 f o rc e [ k n ] displacement [mm] 0% crumb rubber 2% crumb rubber 4% crumb rubber 6% crumb rubber 0 20 40 60 80 100 0 2 4 6 8 10 12 14 16 f o rc e [ k n ] displacement [mm] 0% crumb rubber 2% crumb rubber 4% crumb rubber 6% crumb ruuber 218 m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 epoxy coated lubricant dowel bars cast in concrete pavement containing 2%, 4%, and 6% crumb rubber respectively compared with that contain 0% crumb rubber. the results revealed the using of cr with standard dowel bars (epoxy coated lubricant dowel) is more effective in reducing the pullout load compared with using crumb rubbers with uncoated unlubricant dowel bars, in which the reduction was 25%, 39% and 55% for specimens containing 2%, 4%, and 6% cr respectively. figure (8) shows bond-slip behaviour for the four cases of epoxy coated and lubricated dowel. the positive response regarding to pullout load for dowel bars in rubberized concrete pavement is attributed to increase the elasticity of concrete due to adding the crumb rubber. also, the triple effect of crumb rubber and lubrication with epoxy makes the case of epoxy-coated lubricant dowel bars is the better case of the above cases. we notice that the values of these curves are very few, which indicates that this case is the best of the previous cases. fig. 8 load-displacement curves for the case of coated lubricated dowel bars for different percentages of rubbers. the visual inspection for the dowel concrete interface supports the pullout load test results. in cases of specimens containing coated lubricated dowel bars and 6% cr, insignificant cracks were observed at the joint face as can be seen in figure (9). while for the same case of dowel surface cast in concrete has 0% cr, significant cracks were observed at the joint face as can be seen in figure (10). fig. 9 slip of dowel bar for coated lubricated dowel bars at concrete contains 6% cr fig. 10 slip of dowel bar for coated lubricated dowel bars at concrete contains 0% cr 5. summary and conclusions the using of waste plastic and recycling it, is one of the most important processes to convert the negative effect of these waste to positive point by reducing the demand on natural resources and overcome some structural problems. the dowel concrete friction is one of the main concerns of premature failure of joint and concrete pavement overall. the current study focused on using waste cr particles with different sizes to improve joint movement and reduce the required load to open the joint. the results of the study showed that the use of crumb rubbers particles significantly reduces the pullout load and improve the joint movement and keeping acceptable strength up to using 4-6% percent of crumb rubbers particles from the total aggregate weight. the main conclusions of this research are as follows: 1the use of treated cr by naoh solution with standard dowel bars (epoxy coated lubricant steel dowels) can give a superior reduction in pullout load. it produced 45%, 66%, and 83% reduction in pullout load for the percentages of 2%, 4%, and 6% crumb rubber respectively compared with the reference mix. 2the using of treated cr by naoh solution even with the case of nonstandard dowel bars (uncoated lubricated dowels) or in cases of bad preparing, installing and construction of dowel bars can improve the joint movement and reducing premature failure by reducing pullout load by 25 %, 39% and 55% for the 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[23] l. bronuela, s. ryu, y.h. cho, cantilever and pull-out tests and corresponding fem models of various dowel bars in airport concrete pavement, construction and building materials, 83 (2015) 181-188. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 505 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. studying the effect of chemical treatment and orientation on fracture toughness of kenaf fibre epoxy composites mushtaq albdiry, department of materials engineering, university of al-qadisiyah, iraq. e-mail: mushtaqalbdiry@gmail.com; mushtaq.taleb@qu.edu.iq received on 23 july 2017 accepted on 31 october 2017 published on 15 february 2018 doi: 10.30772/qjes.v10i4.499 abstract: in this paper, the effect of surface modification and fibre arrangements of kenaf fibers on fracture toughness of epoxy composite was investigated. the chemical treatment of kenaf fibers (kfs) with 6 % naoh was achieved, and composites with two different fibre arrangements (x and y) directions were fabricated. values of fracture toughness (kic) measured of the compact tension (ct) specimens for both untreated kenaf fibre-reinforced epoxy (ut-kfre) composites and treated kenaf fibre-reinforced epoxy (treated-kfre) were much better than the neat epoxy. the kic value of the treated-kfre composite in y-fibre direction was the highest of 2.74 mpa.m1/2 while it was 1.45 mpa.m1/2 for the neat epoxy. different toughening mechanisms were noticed in the fracture surfaces of the composites in relation to the fibre reinforcement planar, they are shear yielding and fibre splaying with the x-direction and broken fibers, fibre pullout and fibre delamination with the y-fibre orientation. keywords: kenaf fiber; fracture toughness; alkaline treatment; fiber orientation. introduction in recent years, the development of sustainable or biodegradable materials representing at using natural fibre reinforced polymer composites in commercial and medical applications has attracted a remarkable attention from both academic perspective and industrial viewpoint. this attention has emerged since these materials can be useable instead of non-renewable petroleum-based materials, particularly petroleum-based plastic due to their lighter weight, cheap and provide better stiffness to weight than glass. additionally, by using natural fibres can preserve consumable resources such as petroleum, reducing landfill capacities, and alleviating a global warming impact due to diminishing carbon footprints that are generated by consumption of petroleum [1]. mailto:mushtaqalbdiry@gmail.com mailto:mushtaq.taleb@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 506 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. kenaf fibres are among many different natural fibres with different chemical compositions of cellulose, lignin and hemicellulose (e.g., sisal, ramie, jute, flax, hemp, etc.), highly being used in reinforcing polymer matrix composites due to its high tensile strength and young’s modulus of 930 mpa and 53 gpa, respectively. kenaf as natural (plant) fibers is normally used in reinforcing polymer matrix composites. however, the main drawback of natural fibres is the complex structure of elementary fibres that contain cellulose, hemicellulose, pectin lignin and others; is its hydrophilic nature with strong hydrogen bonds and weak interfacial adhesion which complicates forming bonded interface with a relative non-polar hydrophobic matrix and resulting in poor strength properties of the produced composites [2, 3]. in order to improve the bonded interface between hydroxyl groups in natural fibres with matrix resin, thus different chemical, physical and mechanical modifications or treatments of the natural fibers have been implemented. the chemical treatments (e.g., alkaline treatment, silane treatment, isocyanate treatment, and acetylation) consider the most viable treatments, in which, reagents solution are normally used which contain functional groups that are capable of bonding with the hydroxyl group from the natural fibres. amongst them, the alkaline treatment based on sodium hydroxide (naoh) (or mercerization) is the most widely used for natural fibers, especially for kenaf fibre when reinforcing thermoplastics and/or thermosets. via applying the alkaline chemical treatments ensures removal of lignin, hemicelluloses, pectin, wax and oils, etc. covering the external surface of the natural fibers, breaks and disperses hydrogen bonds in the network structure and increases the number of free hydroxyl groups on the surface of the fibres and therefore fibre reactivity [4, 5]. additionally, the chemical treatment of the natural fibres by alkali enhances the fibre’s surface roughness, which in turn causes surface fibrillization and drastically improves mechanical interlocking and fibre–matrix adhesion. due to the growing demand of using natural fibres-polymer composites in structural applications, there is a need to thoroughly understand the fracture toughness and behaviour of these composites especially determining maximum loads applied to the component that can be carried before creating defects, initiating microcracking and causing local stress concentrations that result in catastrophic failure. thus, numerous studies have been identified the fracture behaviour for different natural fibres-reinforced polymer composites, and others reported the importance of chemical treatments especially alkaline treatment with sodium hydroxide (naoh) on mechanical and thermal properties of natural fibres/polymer composites [3, 6-8]. however, few works in the literature have conducted the influence of chemically treated natural fibres on the fracture behaviour and toughness of composites [7, 9-12]. nosbi et al. [13] discussed the degradation of compressive properties of pultruded kenaf fibre reinforced unsaturated polyester composites. it was found that the strength and modulus of the composite are reduced and the compressive strain at failure recorded an increase due to the formation of hydrogen bonding between polymer molecules and cellulose fibers. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 507 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the effect of reinforced fibre arrangements on the mechanism of toughening and fracture toughness of glass fibre-reinforced composites and natural hemp fibre-reinforced pla was presented by [14, 15], respectively. they found that the fracture energy and toughness increases with increasing ply angle up to 40 ° and then it decreases. nevertheless, there is no particular study has investigated the alkaline treatment of kenaf and its arrangement (orientation) on crack path and fracture characteristics of composites. hence, this study aims to comprehensively understand the role of treated kenaf fibres with naoh in improving fracture toughness of the composites. and understanding the effect of fibre orientations (arrangements) on the fracture resistance of the composites since the properties of the fibrous composite materials are strongly affected by the fibre properties and its microstructural parameters such as fibre length and diameter, fibre distribution, fibre orientation, volume fraction of the fibers and packing arrangement of the fibers. 1. experimental 1.1. material and alkali treatment epoxy (der331) and hardener (jointmine 905-3s) with ratio of 2:1 were used as a polymer resin for kenaf fibre composites. after cleaning and extracting the kenaf fibres, portion of the prepared fibres were treated with 6 % sodium hydroxide (naoh) solution for 24 h at room temperature, then washed by demineralised water and dried under sun light. the sem micrographs for both untreated fibres and treated with naoh are shown in figure 1 a & b. some specifications of the neat epoxy (ne) and untreated kenaf fibre reinforced epoxy (ut-kfre) are listed in table 1. 1.2. composites fabrication a conventional hand lay-up technique with aluminium mould of 110 mm x 110 mm x 16 mm was utilised to fabricate epoxy-kenaf composite. the mould was waxed with release agent before pouring epoxy into it to prevent cured composite from adhesion with the mould. unidirectional kenaf fibres were then placed on top of the resin and a steel roller covered with saturated resin was used to remove air bubbles and maintain a fully impregnated between fibre and polymer resin. the procedure was repeated until the required weight fraction of kenaf fibre (30 % wt.) is consumed. the composite samples of compact tension (ct) geometry as well as a schematic graph showing different fibre orientations-reinforced composites i.e. xdirection and y-direction are illustrated in figure 2 and figure 3 a & b, respectively. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 508 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1: sem micrographs showing untreated kenaf fibre with impurities (a), and treated kenaf fibre with exposed cellulose (b). table 1: specifications of neat epoxy (ne) and untreated kenaf fibre reinforced epoxy composite (ut-kfre). property * ne kfre fiber volume fraction 0 % 30 % density g/cm³ 1.1 0.975 modulus of elasticity gpa 3.2 ± 0.3 13.5 ± 2 tensile strength mpa 75 ± 5 133 ± 2 elongation % 3.5 ± 0.2 5.3 ± 2 *all given properties are experimentally measured in this study. figure 2: the compact tension (ct) geometry used in this study. a) b) all dimensions are in mm 40 2 20 8 a=10 w=42 b=16 ø8 x 2 4 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 509 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3: schematic graph of xdirection fibre orientations in the composite (a), and y-direction (b) according to astm 5045 standard. 1.3. fracture toughness measurement the neat epoxy (ne), untreated and treated kenaf fibre reinforced epoxy (ut-kfre) and (t-kfre) with two different orientations were cut by a diamond saw from the cured composites to dimensions of compact tension (ct) geometry according to astm 5045 standard [16]. the holes were opened using a steel drill, the notch and pre-crack were cut precisely with a band saw and inserting a razor blade, respectively. fracture toughness testing was carried out using a universal tensile machine model lr 50 k with a crosshead speed of 1.5 mm/min. both the load and the displacement values for five specimens from each composite direction (x and y) are tested at room temperature and the averaged is recorded. a critical stress intensity factor (kic) is calculated from the following equations [16]: )( 2/1 w a f bw p k q ic        ………….. (1) for a ct specimen, the shape factor, )( w a f is given by           432 2/3 )(6.5)(72.14)(32.13)(64.4866.0 )1( 2 )( w a w a w a w a w a w a w a f ………….. (2) (a) x-direction p p p p x-axis y-axis (b) y-direction al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 510 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. in order to satisfy the plain-strain conditions, the following size criteria are checked: 2 )/(5.2)(,, yic kawab  (3) where pq is the peak load, b the specimen thickness (16 mm), the crack length (10 mm), w the specimen width (42 mm), and the yield stress of the material. 1.4. the fractured surface study in order to understand the mechanism of fracture and deformation behaviour, the fractured surface of the composite from mode i fracture test was examined by using scanning electron microscopy (sem) model quanta 400 f. the samples were firstly coated with a thin layer of gold to improve the conductivity of the material before doing the test. 2. results and discussion 2.1 chemical treatment the sem images for both untreated kenaf fibres (ut-kfs) and treated kenaf fibres (t-kfs) with 6 % alkali naoh are shown in figure 1 a & b. there is a noticeable difference between the surface morphologies for the ut-kfs and t-kfs in terms of smoothness and roughness. the characteristics of t-kfs surface considerably improved and became cleaner and smoother after the naoh treatment compared to the ut-kfs. in addition, the fine fibres in the bundle are exposed after washing the outer layer of the fibres with naoh while the impurities are clearly noticed in the surface morphology of ut-kfs. hence, the 6 % naoh treatment is adequate to eliminate the impurities from the natural kenaf surface determined in this study. the improved surface morphology would improve the level of interfacial adhesion between the fibre and the matrix under the applied load on the fabricated fiber-reinforced polymer composites. 2.2 fracture toughness the load-displacement curves for the compact tension (ct) specimens made from neat epoxy, untreated kenaf fibre reinforced epoxy (ut-kfre) and treated kenaf fibre reinforced epoxy (treated-kfre) composites with two different x and y fibre directions are presented in figure 4. all ct fracture composite specimens performed better and carried higher tension loads before fracturing than neat epoxy. the composites reinforced by kenaf fibres in y-direction conducted higher loads than these for the reinforced composites by x-direction regardless the considerations of alkali treatment method. this is an obvious indication since the neat epoxy (thermoset resin) is brittle in nature and the reinforced fibres contributed in absorb more energy and carry further load before fracturing. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 511 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the treated-kfre in y-direction ct specimens had the highest tension loads before fracturing where they reached 1777 n, giving the maximum fracture toughness (kic) of 2.74 mpa.m 1/2 , which is almost double its value of 1.45 mpa.m 1/2 for epoxy as shown in figure 5. figure 4: load-displacement curves of the fractured ct specimens under tension. in figure 5, the average values of the fracture toughness (kic) for neat epoxy and the composites are given. the kic values of the neat epoxy considerably increased with the existence of the reinforced kfs whether they are ut-kfs or t-kfs. the influence of the kenaf surface treatment on improving the fracture toughness is clearly observed where it contributed in an increment of about 0.5 mpa.m 1/2 . in other words, considering of 6 % naoh alkali treatment of kfs is working to improve kic values for the ut-kfre composites by 24 % of these untreated composites without taking the orientation of fibre reinforcement in consideration. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 512 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 0 0.5 1 1.5 2 2.5 3 3.5 neat epoxy x-direction y-direction k ic ( m p a .m 1 /2 ) ut-kfre treated-kfre neat epoxy figure 5: fracture toughness of epoxy and composites with two kfsreinforcement directions. 2.3. effect of fibre orientations the kic values for the treated-kfre (y-direction) composites are superior compared with the neat epoxy and epoxy reinforced by x-fibre direction. this is due to the improved interfacial adhesion between the treated-kfs and epoxy which enhanced the stress-transfer from the resinous region to the fibers and consequently enhanced the kic of the treated-kfre composites [17]. the improved treated-kfs and epoxy adhesion may also contribute to detain the growth of the delamination, which potentially occurs under the tensile loading. the fracture surface morphology of the neat epoxy is shown in figure 6. it is brittle fracture showing crazing region. however, with the improved interfacial bonding between the treated-kfs and epoxy, more energy is consumed by fibre before pull-out or broken (fracturing). using the y-fibre to reinforce the composites in this study is further improving its toughness where the applied stress is discreet by continuous treated-kfs that can subsequently affect the toughening mechanism of the treated-kfre composites. a similar conclusion was revealed by fiore et al. [18], it was revealed that the use of unidirectional (ud) kenaf fibres or randomly oriented treated-kfs increased the tensile strength and tensile modulus due to the improved compatibility between fibre and epoxy. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 513 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. crack propagation crack tip 300 μm figure 6: fracture surface of the neat epoxy. the fibre arrangement in anisotropic materials such as polymer-based fibre composites is playing a notable role in changing their toughening mechanisms and mechanical properties since their properties are, in general, varying through each axis and depending on the fibre direction in which they are aligned. for instance, in term of un-treated fibres aligned in x-fibre direction, it was observed that the dominant toughening method is shear yielding of the resinous region and the progressive fibre splaying (see figure 7). the role of chemical modification on the fibre surface aligned in the same fibre direction emerged a little amount of treated kfs pull-out along with broken fibre due to the good interfaces between the fibre and matrix, as shown in figure 8. on the other hand, the kfre composites reinforced by un-treated kfs oriented in 90° (y-direction) exhibited besides the fibre pull-out toughening mechanism other two mechanisms are fibre splitting and fibre delamination as shown in fig. 9. the reason of the appearance of such mechanisms and thereof the high fracture toughness of the composites reinforced in y-fibre direction could be attributed to the large crackbridging zones formed by intact kenaf fibres in the crack wake. the fracture surface of the treated-kfre composites reinforced in y-direction exhibited a broken fibre as shown in figure 9 and figure 10. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 514 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. broken fibre conclusions in this study, composite materials from treated kenaf fibers (kfs) with 6 % naoh chemical treatment and epoxy were fabricated. two different x & y reinforcement fibre directions were applied. the fracture toughness (kic) values of all composites are highly affected by the surface modification of kfs and dependent on the fibre orientations. the composites reinforced by treated kfs in y-direction had the figure 7: fracture surface of ut-kfre composites in x-fibre direction. figure 8: fracture surface of treated-kfre composite in x-fibre direction. figure 9: fracture surface of ut-kfre composites in y-direction. figure 10: fracture surface of treated-kfre composites in y-direction. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 515 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. maximum kic of 2.74 mpa.m 1/2 at 89 % improvement compared to the neat epoxy. several toughening mechanisms were observed changing with the conditions of composite materials i.e., shear yielding and little pullout for the composited reinforced by x-direction and broken fibre and fibre delaminated as well as fibrillation for the composites reinforced by kfs in y-direction. references 1. ho m-p, wang h, lee j-h, ho c-k, lau k-t, leng j, et al. critical factors on manufacturing processes of natural fibre composites. composites: part b. 2012; 43 : 3549-3562. 2. akil hm, omar mf, mazuki aam, safiee s, ishak zam, bakar aa. kenaf fiber reinforced composites: a review. materials and design 2011;32:4107-21. 3. ibrahim na, yunus wmzw, othman m, abdan k. effect of chemical surface treatment on the mechanical properties of reinforced plasticized poly(lactic acid) biodegradable composites. journal of reinforced plastics and composites. 2011;30(5):381-8. 4. mussig j, stevens c. industrial applications of natural fibres: structure, properties and technical applications. uk: john wiley 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toughness of woven flax fibre reinforced epoxy composites. composites: part a 2008;39:1644-52. 10. low im, mcgrath m, lawrence d, schmidt p, lane j, latella ba, et al. mechanical and fracture properties of cellulose-fibre-reinforced epoxy laminates. composites: part a 2007;38:963-74. 11. silva rv, spinelli d, filho wwb, neto sc, chierice go, tarpani jr. fracture toughness of natural fibers/castor oil polyurethane composites. composites science and technology 2006;66:1328-35. 12. wong kj, zahi s, low ko, lim cc. fracture characterisation of short bamboo fibre reinforced polyester composites. materials and design 2010;31:4147-54. 13. nosbi n, akil hm, ishak zam, bakar aa. degradation of compressive properties of pultruded kenaf fiber reinforced composites after immersion in various solutions. materials and design 2010;31:4960-4. 14. triki e, zouari b, dammak f. dependence of the interlaminar fracture toughness of e-glass/polyester woven fabric composites laminates on ply orientation. engineering fracture mechanics. 2016;159:63-78. 15. efendy mga, pickering kl. fibre orientation of novel dynamically sheet formed discontinuous natural fibre pla composites. composites part a: applied science and manufacturing. 2016;90:82-9. 16. astm. standard test method for plain-strain fracture toughness and strain energy release rate of plastic materials. d 5045-99. pa, united states: astm, philadelphia; 2007. 17. kafi aa, magniez k, fox bl. effect of manufacturing process on the flexural, fracture toughness, and thermo-mechanical properties of bio-composites. composites: part a 2011;42:993-9. 18. fiore v, bella gd, valenza a. the effect of alkaline treatment on mechanical properties of kenaf fibers and their epoxy composites. composites: part b. 2015;68:14-21. article al-qadisiyah journal for engineering sciences 12 (2019) 260–265 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: adnan.alsibahy@qu.edu.iq (adnan al-sibahy ) https://doi.org/10.30772/qjes.v12i4.643 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. pullout strength behaviour of self-compacted concrete in aggressive solutions maha sabhan a and adnan al-sibahy a * acivil engineering department, college of engineering, the university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 18 november 2019 received in revised form 22 december 2019 accepted 30 december 2019 keywords: corrosion epoxy coated pullout test a b s t r a c t the aim of this study was to investigate the pullout strength behaviour of self-compacted concrete under corrosion conditions. block samples with two configurations were formulated. a total number of twelve block samples in addition to 24 cubes were tested. the hardened concrete samples were either cured in tap water or exposed to salt solution. a suitable epoxy was used for coating part of the formulated samples. the preliminary mechanical properties and the rate of corrosion were firstly measured, the pullout was then carried out. a comparison was also made with the relevant code of practice. the results obtained showed that both compressive strength and density features exhibited a notable increase at an early age when the samples are exposed to salt solution. the adverse effect of such curing condition appeared at the later ages when the corrosion rate became more intensive. the highest decrease in the value of pullout strength was observed for the reinforced concrete block samples containing epoxy coating reaching to 44.5% less than those cured in tap water. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction it is well known that the steel bars can effectively use in reinforcing the plain concrete to increase its resistance to tension stresses. however, under the conditions of rust and corrosion, maintaining such ability of steel bars is a real challenge for the construction engineers. the rust and corrosion phenomena usually appear at the moist environments and presence of oxygen in addition to salts in the soil or groundwater [1, 2]. consequently, the designed age of the reinforced concrete structures will be affected. the adverse effect of the corrosion of reinforced steel bars was the main concern for many of the published research works [3-6]. most of them focused on the ways of protection of the reinforced steel bars from the impact of environmental conditions. it was noted that the coated method can be effectively used in reducing the effect of corrosion. the coating technique mainly depends upon a buffer layer which works as a thin film over the outer surface of the reinforced steel bars [7]. in general, corrosion of minerals is a result of the formation of what so called rust cell. this cell allows for transition of electrons from the anode pole to the cathode pole via an electronic solution [8]. in case of reinforced concrete, the water filling the inner pores of the concrete is the electronic solution responsible for the transmission of electrons released from the oxidation of the steel bars. the aforementioned transmission solution is usually saturated with a high concentration of calcium, potassium and sodium hydroxides resulting from the processing of cement hydration. it was noted that the presence of the basal environment helps to form a protective layer that protects the steel bars from corrosion. in the structural http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i maha sabhan and adnan al-sibahy /al-qadisiyah journal for engineering sciences 12 (2019) 260–265 261 applications, the bond strength is a function for the integrity of the reinforced concrete composition and usually defined as the force that resists the separation of mortar and concrete from reinforcing steel [9]. the interaction between the reinforced steel bars and the surrounding concrete in addition to the nature of cohesion are the basis of the idea for any structural design [1, 9]. previous studies [10, 11] pointed out that the critical bond stress developed between the concrete and reinforced steel is revealed throughout applying loading parallel to the direction of steel bars. such behaviour can be evaluated using a pull-out test which is indicative of a static strength property of the reinforced concrete composition. recently, many research works have been published regarding the corrosion of reinforced concrete structures. however, no available research was conducted to investigate the pullout strength behaviour of the selfcompacted concrete (scc) elements exposed to aggressive environments similar to those found in the soil and groundwater of the southern parts of iraq. in this paper, the bond strength of scc samples was experimentally evaluated under the conditions of curing in water and exposed to aggressive salt solution. the effect of using epoxy coated was also investigated. a comparison with the expression proposed by relevant codes of practice was then made. 2. experimental work 2.1. materials used in order to get the desired objectives of this study, a high performance selfcompacted concrete mixes were produced using ordinary portland cement complying with the en bs 197-1 [12]. natural sand and crushed gravel were used as fine and coarse aggregates. they have maximum particle sizes of 4.75mm and 10mm, respectively. the corresponding sulfate contents were 0.126% and 0.082%, respectively. both of limestone powder and caplast super-r were used as a filler and superplasticizer admixture, respectively. deformed steel bars with diameters of ø12.5 mm and ø25 mm were adopted in formulating the samples of the block. they have ultimate and yield tensile strength of 660 mpa and 415 mpa, respectively. an epoxy h. polypoxy cr type was used as a corrosion inhibitor for the reinforced steel bars. it is a solvent-free high build epoxy resin that provides a chemical resistant for both concrete and steel bars. it was supplied separately as two parts, namely resin and hardener. 2.2. selection of the concrete mix following the procedure described for the common mix design method [13], an optimal concrete mix was designed in order to obtain a selfcompacted concrete mixture that possesses high flowability and compressive strength in the range of 35 mpa. this in turn gives a concrete mixture with a mix proportion of 1:1.8:2 (cement: sand: grave) by weight. the cement content and w/c ratio of the former mixture were 400 kg/ m3 and of 0.58, respectively. the dosage of the super-plasticizer was 1% by weight of cement. for the assessment purposes, the flowability aspect was measured using slump, flow, j-ring, v-funnel, and l-box test methods. the results obtained for the flowability and compressive strength features are shown in table 1. table 1. flowability and compressive strength values of the selected scc slump (mm) slumpflow (mm) ltest cm vfunnel second j-ring test cm compressive strength mpa at 28 days 265 578 5.5 3 10 36.8 2.3. preparation of salt solution a composite solution of chloride and sulfate salts was prepared as an attack environment for the reinforced concrete samples. the concentrations of these salts are similar to those available in the soil and underground water of the southern parts of iraq. the raw compositions of the former salts were nacl, mgso4.7h2o, and cacl2.2h2o, as shown in fig. 1. the concentration of the former salts are 45.l g/l, 17.9 g/l, and 5.5 g/l, respectively. figure 1. types of salts used in the preparation of aggressive solutions 2.4. preparation of moulds , mixing, casting and curing operations play-wood moulds were designed for the purpose of casting the reinforced concrete blocks. two configurations of wooden moulds were fabricated. the first has a dimensions of 200×120×120 mm (l× w× h) [14] which was designed for running the pullout test for the concrete blocks reinforced with the steel bar of ø12.5 mm. whilst, the second was designed with dimensions of 375×250×250mm (l× w× h) [14] to suit the pullout test for the concrete blocks reinforced with the steel bar of ø25 mm, as shown in fig. 2., while fig. 3. shows the final composition for the beam and block moulds with their steel reinforcements. figure 2. details of moulds: (a) blocks reinforced with ø12.5 mm; (b) blocks reinforced with ø25 mm (a) (b) 262 maha sabhan and adnan al-sibahy /al-qadisiyah journal for engineering sciences 12 (2019) 260–265 figure 3. the final composition of the block moulds with their steel reinforcements the mixing, casting and curing operations were carried out in accordance with bs en12390-2 [15]. cubes samples were also cast to measure the compressive strength and density feature at different ages. following the methodology adopted in this study, all of the concrete samples were firstly cured in water for 7 days. after that, the samples intended to be exposed to aggressive environment were only cured in salt solution for a period of 6 months. the corrosion phenomenon of the reinforced block samples was computed under the conditions of cured in water, exposed to a salt solution with an without epoxy coated after a period of 6 months of exposure. after that period, the pullout test was then performed. 2.5. corrosion measurements the technique of electrical current passing through a specified length of steel bar was used to measure the amount of corrosion. a voltmeter device was used to supply a constant voltage (220 voltage), then the values of electrical current released were recorded, as shown in fig. 4. in such a case, the corrosion of the steel bar is normally accounted for in the form of an affected cross-sectional area, as described in eq.1. a= (∫l)/r (1) where a is the affected cross-sectional area of steel bar due to the corrosion in mm2, ∫is the quality resistance in omm which is equal to 7.36*10-8, l is the length of steel bar in mm and r is the electrical resistance of the steel bar in omm per mm. figure4. corrosion test method 3. results and discussion 3.1. preliminary mechanical properties the results obtained for the mechanical properties of the hardened concrete samples are shown in figs. 5 and 6. it can be seen that the compressive strength of the plain concrete samples tends to increase with the increase of curing age. this is due to the progressing in the hydration of cement paste with time. at early ages, the concrete samples cured in salt solution showed higher compressive strength than those cured in tap water. this behaviour can be explained by increasing the volume of solid hydration products in the present of salt solution. the latter prompts formation of calcium trisulfoaluminate which so called ettringite. at the later curing ages, the former product being unstable and convert to calcium monosulfoaluminate [8, 9]. this in turn means decreasing the value of compressive strength and the effect of salt being appear in terms of disintegration of the concrete. similar behaviour was also noted for the values of densities of hardened concrete samples to that observed for the compressive strength. this supports the justified previously mentioned for explaining the behaviour of compressive strength with time of curing. the percentage increase in the value of density at 7 days for the concrete samples cured in salt solution was about 5% compared with those cured in water. on the other hand, the density value showed a reduction at 180 days age with a percentage decrease reaching to 2%. conversely, a continues increase in the value of density with time was observed for the concrete samples cured in water. this was expected as the empty capillary pores are filled with the solid hydration products. figure 5. the values of compressive strengths at different curing conditions figure 6. the values of concrete densities at different curing conditions 3.2. corrosion behaviour of the reinforced concrete elements the results obtained for the corrosion behaviour of the reinforced block samples at different curing conditions in terms of the value of current passing and the calculated volume of the embedded steel bar are presented in table 2 and figs 7 and 8. maha sabhan and adnan al-sibahy /al-qadisiyah journal for engineering sciences 12 (2019) 260–265 263 table 2. the current values for the reinforced block samples figure 7. the volume of the embedded steel bars of ø25 mm in the block samples at different curing conditions figure 8. the volume of the embedded steel bars of ø12.5 mm in the block samples at different curing conditions it can be seen that the volume of the embedded steel bars tends to decrease with the increase in the time of curing. so, for the purpose of durability evaluation, the behaviour of reinforced concrete element usually monitored for a long-term (at least for a six months) [16]. this is consistent with the results obtained for the plain concrete samples in which the adverse effect of sulfate attack appeared at the later ages. in general, the decrease in the volume of steel bar depends mainly on the nature of curing conditions. it was minimal for the block samples incorporated epoxy coated. whilst a notable decrease in the volume of steel bars was noted for the case of curing in tap water. on the other hand, the highest volume change was observed for the samples exposed to salt solution. this is indicative for the corrosion of the reinforced steel bars and can be explained by the reaction of chloride salt with the outer surface of steel bar [8]. existence of the salt solution prompts the aforementioned reaction throughout disintegration of the concrete cover and increasing its porosity [9]. on this basis, a direct contact can be achieved over the available surface of steel bar. it is important to note that the value of electrical current passing through the steel bar for constant voltages exhibited a constant decrease over time, as shown in tables 2. this represents the concept of the electrochemical process of corrosion phenomenon which results in a volume change of the reinforced steel bars. the percentage decrease in the volume of steel bars of ø25 mm used in reinforcing the block samples at 180 days compared with those cured at 7 days for the cases of curing in water, cured in salt solution and cured in salt solution with epoxy coated were 18, 27% and 5%, respectively. whilst, the results for the steel bars of ø12.5 mm were unrealistic. 3.3. pullout behaviour figs. 9 and 10 illustrate the results obtained for the pullout behavour of the reinforced concrete blocks. except for the ultimate values of pull-out force and slipping, both of these figures showed identical bond-slip curves for all of the tested samples. this was expected as a similar type and composition of concrete was used in this study. it was clearly shown that the ultimate pull-out force increases with the increase of the bar diameters. this mainly due to higher shear resistance propagated over the bar perimeter. such resistance is also dependent upon the geometry of the rib. the percentage increases in the values of ultimate pull-out forces for the steel bars of ø25 mm in respect to those of ø12.5 mm for the block samples cured in water, exposed to salt solution and epoxy coated were 73%, 73 and 78, respectively. similarly, the values of displacements were consistent with their corresponding values of ultimate pull-out forces. consequently, the highest displacement value was recorded for the steel bar of the larger diameter. this means a higher potential of pull-out force is needed to cause the ultimate slipping and failure for the block sample. the role of curing conditions was obvious in the results obtained. for the same diameter of steel bar, the bock samples cured in water show the highest pullout force and slipping values compared with those cured in other conditions. a notable decrease in the values of pullout force and slipping was noted for the block samples exposed to salt solution. the percentages decrease in the values of ultimate pull-out forces for the steel bars of ø25 mm and ø12.5 mm compared with those cured in tap water were 21% and 22%, respectively. the corresponding percentages decrease for the slipping values were 5.7% and 14.4%, respectively. the reason for this reduction may be related to impairment of the bond between the concrete and steel bar resulting from the corrosion phenomenon. such an attitude tends to reduce the cross-sectional area of the bar as early as mentioned. consequently, many voids are formed in the interaction zone between the concrete and steel bar associated with the weakness of the bars itself [17]. the worst scenario was observed for the case of reinforced block samples incorporated epoxy coated. the latter case an indicator of the adverse effect of epoxy on reducing both of the ultimate pull-out force and slipping value. the percentages decrease in the values of ultimate pull-out forces for block samples reinforced with steel bars of ø12.5 mm and ø25 mm containing epoxy coated compared with those cured in water were 44% and 31%, type of element type of curing current value (ampere) at different curing ages 7 days 14 days 28 days 1 month 2 months 3 months 4 months 5 months 6 months block samples reinforced with steel bar of ø25 mm water 190 189.26 185.93 181.1 179 175 164 157 155 salt with epoxy coated 190 190 189.4 188 188 186 184 182 182 salt without epoxy 188.99 188.7 186 175.1 161 161 144 141.5 139.9 block samples reinforced with steel bar of 12.5mm water 85 85 79 99 110 105 114 102 78 salt with epoxy coated 83.5 86 72 102 116 91 72 119 100 salt without epoxy 79.9 77.9 70.7 95.5 93 114 121 44 90 264 maha sabhan and adnan al-sibahy /al-qadisiyah journal for engineering sciences 12 (2019) 260–265 respectively. the corresponding percentages decrease in the slipping values were 19.5% and 22.4%, respectively. such behaviour can be explained by forming a film around the steel bars which considerably tends to reduce the mechanical friction resulting at both surfaces of concrete and steel bars. the latter friction is the major source of bond strength. based upon the above results two opposite roles were noted for the epoxy coated: preventing the corrosion to be occurred and inducing less bond to the reinforced concrete composition. figure 9. pullout strength-displacement relationship for block samples reinforced with steel bar of ø12.5 mm figure 10. pullout strength-displacement relationship for block samples reinforced with steel bar of ø25 mm figure 11. the failure modes of the block samples: (a) extension of the slipping cracks (b) completely failure in terms of the failure modes, the cracks appear firstly at the top surface of the samples underneath the holding plate associated with slipping of the steel bar. when the pullout load increases, the cracks extend to the sample height, as shown in fig. 11-a. completely splitting failure mode is then took place at the point of ultimate load, as shown in fig. 11.b. 3.4. compassion with the code of practice in order to explore the structural applications of the experimental results obtained in this study a comparison was made with the relevant code of practice. in this regards, ceb-fip [18] proposed eq.2 to calculate the bond strength in term of shear resistance of a specified steel bar embedded within a concrete composition, as follows: τ𝑏𝑢,𝑠𝑝𝑙𝑖𝑡 = ƞ26.5 ( fcm 25 ) 0.25 ( 25 ∅ ) 0.2 [( cmin ∅ ) 0.33 ( cmax ∅ ) 0.1 + km ktr] (2) where ƞ2 is a parameter representing the bond condition and taken as 1.0 for good bond and 0.7 for all other bond conditions, fcm is the cylinder concrete compressive strength in mpa, ø is the diameter of the anchored bar in mm, cmin is the min. cx, cy and cmax is the max cx, cy taken based on the fig. 12, km represents the efficiency of confinement from transverse reinforcement which has a value of 12 where bars are confined inside a bend of links passing around the bar of at least 90° and ktr is calculated using eq. 3. figure 12. shows the spacing and cover of the straight bar; cx and cy 𝑘𝑡𝑟 = ƞ1𝐴𝑠𝑡 ƞ𝑏ø𝑆𝑡 ≤ 0.05 (3) where ƞ1 is the number of legs of confining reinforcement crossing a potential splitting failure surface at a section, ast is the cross-sectional area of one leg of confining bar in mm2, ƞb is the number of anchored bars or pairs of lapped bars in the potential splitting surface and st is the longitudinal spacing of confining reinforcement in mm. applying eq. 2., taken into consideration ƞ2value is 1.0 for samples cured in water and 0.7 for those epoxy coated. on the other hand, the ceb-fip [18] suggested the value of ƞ2 for the corroded reinforcement is 0.4 for the non-confinement elements. the calculated bond strength with their corresponding measured values are illustrated in table 3. table 3. the measured and calculated values of bond strength (τ) type of curing experimentally measured values of ( 𝛕 ) in mpa calculated values of (𝛕) using eq.2 in mpa ø 25 ø 12.5 ø 25 ø 12.5 cured in water 12.42 12.16 14.00 16.00 exposed to salts 9.79 9.95 5.64 6.54 epoxy coated 8.47 7.36 9.88 11.45 it can be seen that the highest differences between the measured and calculated results of the bond strength were noted for the block samples. this may be due to the nature of pullout technique which represents a direct test method. on this basis, eq. 2 needs to be amended in order to fit the experimental measurements obtained in this study. it was found that the suggested values of (ƞ2) are as per in table 4. (a) (b) maha sabhan and adnan al-sibahy /al-qadisiyah journal for engineering sciences 12 (2019) 260–265 265 table 4. the suggested values of ƞ𝟐 type of curing ƞ𝟐 values ø 25 ø 12.5 cured in water 0.88 0.76 exposed to salts 0.60 0.70 epoxy coated 0.64 0.48 4. conclusions this study was conducted in order to investigate the bond strength behaviour of reinforced self-compacted concrete elements exposed to different curing conditions. the main findings of this study can be summarized as follows:  the compressive strength and density values showed a notable increase at the early ages when the concrete samples exposed to aggressive solutions. however, a contrast behaviour was noted at the later ages (i.e. beyond 120 days) where a decomposition for the main components of cement paste took place.  the rate of corrosion increases with an increase in the time of exposure to the salt solution. such behaviour was only noted for the uncoated steel bars, whilst the epoxy coated prevent the occurrence of the corrosion phenomenon.  the pull-out strength value adversely affected when the reinforced steel bar of the concrete block samples exhibited a notable corrosion at the external surfaces due to exposure to the salt solution. the percentage decreases in such a case compared with that of cured in tap water were 17.7% and 21% for the steel bars of ø12.5 mm and ø25mm, respectively.  the highest decrease in the value of pull-out strength was observed for the reinforced concrete blocks containing an agent of epoxy coating. this was mainly due to the role of such agent in reducing the adhesion between the steel bars and the surround concrete. the percentage decreases in the former reinforced block samples when compared with those of free coating agent and cured in tap water were 44.5% and 31.2% for the steel bars of ø12.5 mm and ø25mm, respectively. references [1] mindess s, young jf, darwin d. concrete. new jersy: prentice-hall; 2002. 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https://www.sciencedirect.com/science/journal/09589465 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 550 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. measurement of liquid level in partially-filled pipes using a noise of electromagnetic flowmeter muneer a. ismael, department of mechanical engineering, engineering college, university of basrah, basrah, iraq. e-mail: muneerismael@yahoo.com,muneer.ismael@uobasrah.edu.iq rafil m. laftah, department of mechanical engineering, engineering college, university of basrah, basrah, iraq. e-mail: drrafil74@gmail.com mustafa n. falih, department of mechanical engineering, engineering college, university of basrah, basrah, iraq. e-mail: mustafa1986@gmail.com received on 10 octobor 2017 accepted on 13 december 2017 published on 20 february 2018 doi: 10.30772/qjes.v10i4.504 abstract: this paper investigates the measurement of liquid level in partially filled pipes utilizing an electrical noise signal (transformer signal) generated in electromagnetic flowmeter namely, transformer signal. the study was conducted by experiments and the collected data were analyzed statistically using artificial neural network (ann). the experimental study was achieved by building a laboratory rig containing the main parts of electromagnetic flowmeter. the main parameters which have been studied were the liquid level, magnetic field strength ( = 0.00809t, 0.03308t, 0.05301t), liquid temperature ( = 11º to 21.5º ) and liquid electrical conductivity ( = 0.11225, 3.08, 210, ms/cm). the collected data were analyzed using the back propagation neural network technique included in matlab software 2009. the results show that the transformer signal is greatly influenced by variations of the liquid level inside partially filled electromagnetic flowmeter. the electrode position of ( = 160º) has had the strongest response to liquid level. the electrode position effect on the transformer signal is the greatest compared with that of the liquid temperature and the strength of the magnetic field. generally, the transformer signal was found to be an increasing function with decreasing of liquid level. keywords: electromagnetic flowmeter, liquid level, partially-filled pipes, noise signal. nomenclatures magnetic field density, blocking distance (tesla) pipe diameter (m) potential voltage (volt) liquid level (m) current density vector (ampere/m 2 ) t temperature of liquid ( o c) mean velocity (m/s) mailto:muneerismael@yahoo.com mailto:muneer.ismael@uobasrah.edu.iq mailto:drrafil74@gmail.com mailto:mustafa1986@gmail.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 551 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. greek symbols electrical conductivity (ms/cm) angle of electrode position (degree) magnetic permeability of free space (h.m -1 ) change of induced signal (v) z distance between vertical axis and the twisted wires (m) abbreviations anns artificial neural networks emf electro magnetic flowmeter mse mean squared error psd phase-sensitive detector introduction electromagnetic flowmeter (emf) is a non-invasive device that measures the average velocity and consequently the flow of electrically conductive fluids like water, slurry, conducting chemicals, sewage, liquid metals and liquid foods through a pipe and even in open channels. its principle of operation is relied on faraday’s law of induction, whereby an electrical field is induced in a moving liquid in the presence of a magnetic field if both the moving liquid and the magnetic field are perpendicular. the emfs are developed to stand in the measurement of flow through open channel and free surface flows as in partially filled circular pipes. partially filled pipes are encountered in industry, and especially in drainage and waste pipes carrying radiative and chemical liquids. the electromagnetic flowmeters measure the fluid velocity hence, the flowing area is the determinism to compute the flow rate. therefore, when the fluid does not completely fill the pipe, additional attention will be needed to the emf. in 1930, william [1] prepared the first electromagnetic flowmeter-like device when he used the electromagnetic induction to measure the flow of conductive solutions and mercury in closed pipes. in the same year, kolin [1] suggested the use of electromagnetic induction flowmeter to measure the flow of blood in blood vessels. hemp [2] introduced a promising study regarding the theory of eddy currents in the electromagnetic flowmeter. he considered the problem of eddy currents and transformer (noise) signals in electromagnetic flowmeter. he gave a procedure for solving this problem. al-rabeh [3] and hemp [4] discussed the ability of dry calibration of the emf to reduce the expensive real calibration. bates [5] introduced a novel design of multi-electrode electromagnetic flowmeter. his design provided nine conventional electromagnetic flowmeters housed in a single body to adverse the flow conditions immediately downstream from a header tank. rosales and sanderson [6] provided a model of streaming current noise generated by the interaction of turbulence with charge distribution, which occurs in the liquid, close to the surface of the insulating liner of an electromagnetic flowmeter, because of charge species being absorbed by the lining material itself. such noise exists whether the electromagnetic field of the flowmeter is exited or not. early innovation published works regarding the emf when the flowing liquid does not completely fill the pipe (partially filled) can be found in [7, 8, and 9]. bonfig [10] wrote an article prescribing a new development in magnetic flow measurement in partially filled open channels. he suggested that the flow rate is obtained by multiplying an electrical signal proportional to the mean velocity of the liquid and with an electrical signal proportional to the filled cross-section. barker [11] invented a method for measuring total liquid volume flow in partially full cylindrical pipes, and apparatus for practicing the method. he explained that the total measurement of both flow velocity and liquid level must be made to calculate total volume flow for this condition. doney [12] constructed an electromagnetic flowmeter worked in partially filled pipes having high accuracy, the ability to handle fluid with high solids content and low maintenance design. godley [13] reported a document covering the operational information about the flow measurement of water industry in partially filled conduits. he mentioned the most important conditions that constraint the general flow measurement method in such situation. these conditions are due to the hydraulic, impurities in the fluid, physical and environmental. ismael [14] performed a theoretical analysis and extensive experimental study on partially filled electromagnetic flowmeter. theoretically, the two main parts of the electromagnetic al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 552 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. flowmeter were optimized to give a predictable flow signal sensitive to neither changes in the liquid level nor changes in the velocity distribution of the metered liquid for the same flow rate. lucas and leeungculsatien 2010 [15] have used the comsol multiphysics to design the emf for measuring the velocity profile of single and multiphase flow. they assumed an array of point electrodes, by which the matrix inversion method is utilized to reconstruct the velocity profiles from the output of these electrodes. ji et al. 2013 [16] have proved by theoretical analysis and experiments the feasibility of the emf in partially filled pipes. they used arc-shaped electrodes for flow signal and a pair of injection electrodes for detecting the liquid level. watral et al. 2015 [17] presented and described in detail the emfs used for open channels and their methods of signal processing. they also discussed the concept of low-energy electromagnetic flowmeter. justensen 2016 [18] studied the performance of emf when they installed in different orientations. they found significant shift in the accuracy with different orientation when respect to upstream elbow. the idea of the present work is to make the emf measure the liquid level in partially filled circular pipes without any auxiliary sensor. this can be achieved by utilizing some noise signal inherent in the electromagnetic flowmeters namely, transformer noise signal. it is believed that this new technique is better and cheaper than the other techniques provided with emf, such as ultrasonic level sensor, resistance sensor, and capacitor sensor. due to our best knowledge, this technique, which may violently reduce the cost of emf handled in partially filled pipes, has not been discussed in the literature. 1. basic theory and problem definition the classical theory and principle of the electromagnetic flowmeters is well established and can be found in many references on the subject. the most important of which is an early book by shercliff in 1962 [19]. the conventional instrument uses a uniform magnetic field and small "point" metal electrodes in an insulating pipe of circular cross-section. this configuration has the advantage that the signal is proportional to the flow rate when the velocity distribution in the liquid inside the flowmeter volume is rectilinear and axisymmetric. in electromagnetic flow-measurement the fluid is assumed to be non-magnetic (has a permeability of free space ). the fluid is furthermore assumed to obey ohm's law, so that current flow is proportional and parallel to the electric field referred to axes moving with the fluid, the electrical conductivity is assumed isotropic and unaffected by the magnetic field or the fluid motion. currents due to convection of charge by the fluid motion are neglected because such charge (necessary to account for any divergence of the electric displacement in the fluid) has been always very small. thus, the current flow in the fluid is taken to be governed by ohm's law in the form [14]: ………... (1) where is the current density vector, is the conductivity, is the potential voltage and is the velocity of liquid. under specified circumstances, the final form of the equation that prescribes the induced flow signal ) in electromagnetic flowmeter can be written in the following form [19]: m vdbu  …………… (2) where is the applied magnetic field, is the flowmeter diameter and is the fluid mean velocity. in a partially filled pipes, the domain of eq’n (2) is that the filled portion of the flowmeter volume. thus, the flow signal induced in the electrodes is the resultant of an infinite number of generators dispersed into the fluid. the output of each generator (figure 1) is proportional to the local flux density and the local fluid velocity. this output voltage is shunted by the fluid surrounding the generator, as a consequence of which al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 553 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. only a portion of signal is seen at the electrodes. the circuit surrounding the single generator from the top to the bottom of the flow tube may therefore be represented by a network of fluid-equivalent resistors r 's [20]. (a) (b) figure 1: (a) uniform magnetic field, (b) liquid equivalent resistance. 1.1. noise signals in electromagnetic flowmeter since the present paper concerns with the liquid level measurement, we will make more attention to utilize other influence of variation, the liquid level. it is well known that any electromagnetic flowmeter uses ac magnetic field is incorporated with a noise signal known as "transformer signal". the liquid inside the flowmeter is a major part of the circuit generating the transformer signal, hence, it is expected that the liquid level directly affects this noise signal. the present idea is to utilize the transformer noise as a measure of the liquid level inside the electromagnetic flowmeter pipe. however, there are other noise signals but their order of magnitude is much less than the transformer noise. the conventional electromagnetic flowmeter is carefully designed to avoid most of these noises. 1.2. transformer noise in order to measure the flow signal, it is necessary to connect wires to the electrodes and lead them out of the flowmeter tube to the detection circuit. this loop leads to the danger of pick-up from external fields and from the electromagnet itself. this noise signal sometimes referred as quadrature voltage because it assumed to be 90 o out of phase with ac flow-induced voltage. it is worth mentioning that the transformer noise exists even when the flow is stopped because it is generated due to the interaction of the applied magnetic field and the measuring closed loop. hemp and youngs [21] have reported an approximate calculation of transformer signal for fully filled pipes: ……………......... (3) (a) (b) figure 2: origin of transformer noise in fully filled pipes for two views (a) and (b). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 554 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. where is the angular frequency, is the magnetic flux, is the radius of pipe shown in figure 2, and is a dimensionless number calculated as follows [21] (figure 2): b z f    1 ……………………….. (4) 2. experimental set up generally, in conventional electromagnetic flowmeters, a great attention is done to obviate the unwanted noise signal and especially the transformer signal. the general procedure followed for this task is a common electronic circuit known as a phase sensitive detector (p.s.d.). the attention of the present study is focused on the experimental analysis of such transformer signal. to achieve the related experiments, it is required to build a real rig consists of a real laboratory electromagnetic flowmeter provided with many supplementary measurement instruments to assist in collecting a huge experimental data. as mentioned previously, the transformer noise is generated due to the interaction between the applied magnetic field and the loop composed of electrodes leads, liquid path, and the instrument that reads the output signal. in other words, the transformer noise exists even when the flow is stopped. this feature serves in reducing the efforts of the experimental work, i.e. the experiments are conducted with no flow provided that the liquid and the magnetic field exist in the flowmeter tube. the main two elements in the present study are as follows: 2.1. primary element the material of the metering tube must be electrically insulated to prevent the shorting of the level induced signal and non-magnetic in order to avoid its effect on the magnetic field across the fluid. for this purpose, a pvc pipe with an inner diameter of 107.2 mm and outer diameter of 110.6 mm was elected. a 500 mm length of this pipe was cut to achieve a flowmeter length of about 5 . this length is sufficient to ascertain the end boundary conditions of electromagnetic flowmeter. the level signal is decided to be picked up by point electrode type because this type is easiest to implement, most reliable and it is more convenient for the purpose of the present aim. the optimum position of these electrodes is about 53°-160°(six pairs of electrodes) below, upper and in the center of the level meter pipe horizontal axis [14], so the experiments are enabled to be conducted even when the liquid level drops to 0.03 (figure 3). for comparison enhancement purpose and to expand the experiments to cover fully filled experiments it was decided to distribute these electrodes on the specified distance from each other, of course each opposite pair works individually, were arranged on the level meter liner. these electrodes were manufactured from a 4 mm diameter, 316l stainless steel rod. this (non-magnetic) material has a very good resistance to wear and corrosion also; it has high electrical conductivity property. the best electrode to pipe diameter ratio is 1/20 [22] hence, 4 mm electrode diameter is the commercially available that is closest to this ratio. each electrode has a length of 7 mm and fixed in a drilled hole through the liner in such a way to be flushed with the inner surface of the liner. 2.2. secondary elements in conventional electromagnetic flowmeter, the task of the electronic circuit is to amplify and demodulate the voltage picked up by the electrodes. the demodulation refers to the phase shift between the flow signal and the transformer signal, which is equal to 90 o . the famous relatively simple technique used for this purpose known as the phase-sensitive detection (p.s.d.). the phase-sensitive detector is an appliance, which multiplies the buffered electrode signal by +1 and -1 at a rate determined by a control signal. the control signal (usually square wave) must be in phase with the flow signal and hence with the magnetic field excitation, it may be driven from the excitation source. a schematic diagram of the phase-sensitive detector is illustrated in figure 4 the details of the real electronic components of this circuit are illustrated in [14]. keeping in mind that our experiments are to be conducted with no flow, a slight modification was made on the al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 555 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. circuit that is canceling the averaging stage, i.e. the electrode (transformer) signal is permitted to pass as ac rather than dc signal (figure 5). in general, the idea of the present technique is to operate the emf with allowing the transformer signal for a while to measure the liquid level and then attenuating this signal to measure the flow signal. this process can be achieved by providing the emf by a simple selector switch. figure 6 shows the real experimental set up. figure 3: the liner and the electrode system assembly. figure 4: conventional phase sensitive detector with liquid flow [14]. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 556 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: present using of the phase sensitive detector with no flow [14]. figure 6: the testing rig and instrumentations (1)d.c. power supply (2)testing tube (3)the magnet (4)-signal processor (5)multi-meter (6)oscilloscope (7)mineral water tube (8)tap water tube (9) salt water (10)the electrodes (11)reference signal. 3. results and processing 3.1. raw results the main laboratory experimental measurements were represented by varying the liquid level, and measuring the generated transformer signal from each pair of electrodes. this procedure has been repeated for three types of liquid these; mineral water, tap water and well salt water with electrical conductivity σ of 0.11225, 3.08 and 210 ms/cm, respectively. the applied magnetic field was varied as, = 0.0809, 0.03308 and 0.05301 tesla. the experimental measurements have been carried out at different temperatures, = 11 – 21.5 o . in all measurements, the transformer signal was recorded as d.c. signal. however, in the following displayed experimental results we have chosen = 0.03308 tesla and = 11 o c. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 557 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7 depicts the data of upper electrode position ( = 53 o ), it is clear from this figure that the sensed liquid level is limited to be 8.295 cm only. the magnitude of the transformer noise is greater according to the following sequence: mineral water, tap water, salt water. this is because of the wide range shift in the electrical conductivity. the values of salt water are about 15 times less than the other two water types, this due to the great shift of the electrical conductivity of salt water, which is about 70 times larger than that of tap water. figure 8 shows the results of electrode position, = 90 o , at the mid-level meter plane. in this position, the sensed liquid level is lowered to 5.53 cm. it can be seen from this figure that in the case of salt water, the transformer noise signal is slightly changed with the liquid level. the reason of such behavior was unclear at the early stages of data recording, but with many repeated data, the explanation of such behavior was attributed to the contamination process of deposits on the electrodes inner surface, where the salt water contains many sediments and composition. figure 9 shows the lower electrode position measurements ( = 160 o ). the sensed liquid level is further lowered to 0.6 cm. it is worth mentioning here that an electrode position lower than the conventional position ( = 90 o ) is highly recommended for partially filled electromagnetic flowmeter [14]. however, the present results appear to be more stable and smooth with fewer problems. by referring to figures 7 and 8, it can be seen that when the liquid level falls to be close to the electrode surface, the transformer signal increases sharply. this abrupt change in the transformer signal is not seen at the lower electrode position ( = 160 o ). the reason of this phenomenon may refer to the asymmetry of liquid quantities over and under the electrodes connecting line. the liquid quantity governs the number of paths of transformer current. however, when the electrode positioned under the conventional position ( = 90 o ), the effect of liquid symmetry is reduced as the liquid quantity below the electrode plan is already small. in general, it is noticed (in all electrode positions) that when the liquid level increases, the magnitude of the transformer noise signals is decreased. this behavior is observed in all recorded data which are reached to (690) readings (these data are not displayed for brevity). this behavior can be attributed to the following: increasing the liquid level leads to the increase of the equivalent resistance (figure 1), hence the generated current will be reduced meanwhile the decrease of the liquid level leads to lowering the number of equivalent resistors which in term results in an increasing the transformer current. figure 7: variations of the induced signal with changing liquid level at 53º electrode position and 0.03308 tesla of magnetic field and = 11 o al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 558 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 8: the variation of the induced signal with changing liquid level at 90º electrode position and 0.03308 tesla of magnetic field and = 11 º . figure 9: the variation of induced signal with changing liquid level at 160º electrode position and 0.03308 tesla of magnetic field and = 11 º . al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 559 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. however, it is found that analyzing these huge data directly does not give comprehensive information about the real relation between the liquid level and the recorded signal. therefore, the study is turned to use another technique, namely the artificial neural network ann. 3.2. ann model artificial neural networks are non-linear mapping structures based on the function of the human brain. they are powerful tools for modeling, especially when the underlying data relationship is unknown. anns can identify and learn correlated patterns between input data sets and corresponding target values [23]. neural networks are composed of simple elements operating in parallel. commonly neural networks are adjusted, or trained, so that a particular input leads to a specific target output. such a situation is shown in figure 10. figure 10: basic operation of ann. the neural network model is developed to predict the liquid level which depends on the results of the experimental work as training and testing data. the total experimental data are divided into two sets: a training set and a testing set. the training set is used for computing the gradient and updating the network weights and biases to diminish the training error, and find the relationship between the input and output parameters. the test set is used to evaluate the generalization ability of the learning process. in this study, the testing set contains approximately 20% of total the database. the total number of (690) test cases were utilized. the training set contains (552) cases and the testing set comprises of (138) cases. the parameters used in this study are shown in table 1. table 1: input and output parameters. item parameters range of parameters units from to input parameters transformer noise in voltage (v) -18.23 4.95 mv electrode position ( ) 53 160 degree strength of magnetic field ( ) 0.00809 0.05301 tesla electrical conductivity ( ) 0.1225 210 ms/cm water temperature ( ) 11 21.5 ◦ output parameter liquid level (h) 0.8 10.2 cm al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 560 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3.3. the proposed network in this study, the network is tested with different number of hidden layer configurations with an increasing number of nodes in each hidden layer(s). different activation function arrangements are investigated. the optimal topology is determined using the conjugate gradient back-propagation with polakribiere update (traincgp) as a training function with activation function as hyperbolic tangent (tansig) function for two hidden layers and output layer. the used ann was implemented in matlab 2009. the proposed network gives the best mean square error (mse) and correlation factor (r) for both training and testing data as shown in figure 11.the optimal structure of the proposed network is 5:16:19:1 topology (5 neurons in input layer, 16 neurons in the first hidden layer, 19 neurons in the second hidden layer and a single neuron in the output layer) as shown in figure 12. figure 11: train and test mse vs. epochs of the best two hidden layer network. figure 12: configuration of neural network structure (5-16-19-1). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 561 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figures 13 and 14 present the outputs versus the targets as open circles. the solid line indicates the best linear fit and the dashed line indicates the perfect fit (output equals target). the values of the slope are (0.963) and (0.952) respectively, interceptions with y-axis are (0.226) and (0.349) respectively, and correlation coefficients are (0.988) and (0.975) respectively. these values indicate that the mapping of neural network for the training and testing data is very good. figure 13: training regression of the proposed two hidden layer network. figure 14: testing regression of the proposed two hidden layer network. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 562 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figures 15 to 17 show a comparison between the experimental results and ann model against the effect of changing in the induced voltage to the liquid level for three types of water (mineral, tap, salt) at constant magnetic field (0.03308 tesla), constant temperature ( = 11º ) and at electrode position = 53º (the other positions are not shown for brevity). these comparisons confirm the obtained results from the ann model represent good result. figure 15: comparison between the experimental result and neural network result of mineral water liquid type at electrode position 53º and magnetic field 0.03308 tesla and = 11º . figure 16: comparison between the experimental result and neural network result of tap water liquid type at electrode position 53º and magnetic field 0.03308 tesla and = 11º al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 563 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 17: comparison between the experimental result and neural network result of salt water liquid type at electrode position 53º and magnetic field 0.03308 tesla and = 11º . conclusions the present paper investigates, experimentally and statistically, the possibility of utilizing the inherent transformer noise signal in electromagnetic flowmeter to measure the liquid level of partially filled pipes. the nonlinearity and complexity of the relation govern the transformer signal motivate the use of the artificial neural networks to deal with the extracted huge experimental data. the back propagation neural network, which is a multi-layered feed forward neural network, has been proven to accurately predict the liquid level that increases the accuracy and reduces the cost of electromagnetic flowmeter when it designed for the partially filled pipes. the most important conclusions that can be drawn from the present study are the followings:  the liquid level is the stronger parameter that affects the transformer noise signal than other parameters.  the transformer signal increases with the decrease of the liquid level and vice versa.  the transformer signal generated with salt water is prominent with respect to those generated with mineral and tap water. for example, when = 160 o , = 0.03303 tesla, = 11 o and = 2 cm, the salt water signals are 2.5 times and 7 times greater than mineral and tap water, respectively.  two hidden layers neural network model significantly improves the performance of the network. the configuration (16-19) (16 nodes in the first hidden layer, and 19 nodes in the second hidden layer) is proved to be very efficient for predicting the liquid level.  the conjugate gradient backpropagation with polak-ribiere updates (traincgp) algorithm gives better performance and regression for both training and testing phases. biodata -muneer a. ismael is assistance professor (phd) at university of basrah, engineering college, department of mechanical engineering. his interested researches are electromagnetic flowmeters, nanofluid, and mixed convection. -rafil m. laftah is a lecturer (phd) at university of basrah, engineering college, department of mechanical engineering. his interested researches are fracture mechanics, artificial neural network, and finite element. -mustafa n. falih is msc. student in university of basrah, engineering college, department of mechanical engineering. he is an engineer in south oil company, basrah, iraq. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 564 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. references 1. baker, r.c., flow measurement handbook, industrial design, operating principals, performance and applications. cambridge university press, 1 st ed., uk, 2000. 2. hemp, j., theory of eddy currents in electromagnetic flowmeter, in “journal of physics d” 24, 1990, pg. 244-251. 3. al-rabeh, r.h.; baker, r.c., on the ability to dry calibrate an electromagnetic flowmeter, in „journal of physics e” 19, 1986, pg. 203-206. 4. hemp, j., a technique for low cost calibration of large electromagnetic flowmeters, in „flow measurement and instrumentation” 12, 2001, pg. 123-134. 5. bates, j.c.; franklin, b., the performance characteristics of a novel multi-electrode electromagnetic flowmeter, in „measurement” 35, 2004, pg. 399-408. 6. rosales, c.; sanderson, m.l., streaming current noise generation in electromagnetic flowmeters measuring conducting fluids, in „flow measurement and instrumentation” 14, 2003, pg. 97-108. 7. mannherz, d.e.; yard, j.s., electromagnetic flowmeter usable in less than full fluid lines, in „us patent” 3,991,612, 1976. 8. searle j.l., electromagnetic flowmeter usable in less-than full fluid lines, in „u.s. patent” 4,036,052, 1977. 9. marsh, l.b., fluid flow meter, in „u.s. patent” 4,083,246, 1978. 10. bonfig, k.w., new developments in magnetic flow measurement in partly filled open channels, technical and mythological in measurement, in „9th imeko water conference” 1982, pg. 131-140. 11. barker, l.w., method and apparatus for measuring total liquid volume flow, in „u.s. patent” 4,393,451, 1983. 12. doney, b., electromagnetic flow measurement in partially filled pipes, in „journal of fluid piping systems”, magnetic flow products for abb instrumentation, 1999. 13. godley, a., flow measurement in partially filled closed conduits, in „flow measurement and instrumentation”, 13, 2002, pg. 197-201. 14. ismael, m.a., adaptive numerical solution and experimental study into the design of the electromagnetic flowmeter for partially-filled pipes, ph.d. thesis, university of basrah, 2007. 15. lucas, g.p.; and leeungculsatien, t., a new method of measuring velocity profiles using a multi electrode electromagnetic flow meter, in „6th world congress on industrial process tomography, 69 september 2010, beihang conference center, beihang university, china. 16. jia, s.; chunqing, q.; hongbin, z., multi-parameters measurement based on stm32 arm of dualexcited electromagnetic flow meter in partially filled pipes, in „applied mechanics and materials’ vol. 347-350, 2013, pg. 682-685. 17. watral, z.; jakubowski, j.; michalski, a., electromagnetic flowmeters for open channels: current state and development prospects, in „flow measurement and instrumentation” 42, 2015, pg. 16–25. 18. justensen, j.c., the effects of meter orientation downstream of a short radius elbow on electromagnetic flow meters, msc. thesis, utah state university, 2016. 19. shercliff, j.a., the theory of electromagnetic flow-measurement, cambridge university press, uk, 1962. 20. mannherz, d.e.; yard j.s., electromagnetic flowmeter usable in less-than full fluid lines, in „us patent” 3,991,612, 1976. 21. hemp, j.; youngs, i., problems in the theory and design of electromagnetic flowmeters for dielectric liquids. part 3a. modelling of zero drift due to flux linkage between coil and electrode cables, in „flow measurement and instrumentation” 14, 2003, pg. 65–78. 22. hemp, j.; wyatt, d.g., a basis for comparing the sensitivities of different electromagnetic flowmeters to velocity distribution, in „journal of fluid mechanics” 112, 1981, pg. 189-201. 23. engelbrecht, a.p. computational intelligence, 2nd ed. john wiley & sons ltd, england, 2007. http://iopscience.iop.org/journal/0022-3735 http://iopscience.iop.org/journal/0022-3735 article al-qadisiyah journal for engineering sciences 13 (2020) 167–174 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: muhanedamuhaned@gmail.com ( muhaned a. shallal) https://doi.org/10.30772/qjes.v13i3.662 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. effect of filling steel tube chords by concrete on the structural behaviour of composite truss girders kareem mohammed alnebhan a, muhaned a. shallal a* acivil eng., eng. college, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 23 june 2020 received in revised form 12 july 2020 accepted 20 july 2020 keywords: concrete filled steel tube truss girder concrete deck slab slip, shear connectors warren truss composite steel-concrete a b s t r a c t in this study, three specimens of warren truss girders composite with concrete deck slab were tested experimentally under a central monotonic load to study the effect of the existence of concrete inside the chords. the load capacity, deflection, slip between the concrete slab and steel tube, and failure modes were reported. both chords were filled with concrete to the first specimen, only the lower chord was filled with concrete and the upper chord remained hollow to the second specimen and both chords were kept hollow in the third specimen. the result indicated that the existence of concrete inside the chords has a significant effect on the load capacity, failure pattern, and the slip. the steel tubes of the upper chord filled by concrete prevent surface plasticity failure of the upper chord under loading and increase the ultimate load by 6.68 %. also, filling the lower chord with concrete prevents the surface plasticity failure in the supports zone and caused an increase in the ultimate load by 39.59 %. the slip at the end of the specimen of two chords filled with concrete is less by 71% than the end slip of specimen of hollow top chord and higher by 46.8 % than the specimen of two hollow chords. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction for several decades, the use of steel in combination with concrete has been a more successful and widely applied structural system. the applications of this type of composite material were extended to numerous structural constructions like multi-story buildings, e.g., concrete slab supported by steel beams. other applications are the road bridges, e.g., concrete decks supported by steel frame or truss, as well as factories and commercial buildings johnson et. al. [1]. steel-concrete composite in the structures aims to preserve the advantages of both materials steel and concrete nie et. al. [2]. when the concrete exposed to compression, it exhibits significant strength and high rigidity, while when exposed to tension, it has precarious behaviour and with time it is likely to shrink and creep. on the other hand, the steel structures have low fire resistance and it is prone to lateral and local buckling although it has high ductility and significant load capacity oehlers et. al. [3]. the concrete-filled steel tube (cfst) was used in columns han et. al. [4], beams [5-7], and truss girders huang et. al. [8]. the tensile strength is improved by about 11% when using cfst compared to a hollow steel tube han et. al. [9]. the hollow braces and the chords filled with concrete are the common apparatuses in (cfst) trusses. the tensile strength and the compressive strength of the chords are improved. the steel tube of the upper chord is prevented from buckling inward in compression and the steel tube of the lower chord is avoided from contraction inward in tension. the cfst also improved the whole flexural stiffness of the truss and the strength of the joints [8, 10-12]. numerous http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 168 kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 studies have been conducted on the behaviour of cfst truss girders in flexural with different parameters [13-22]. chan et. al. [13] found that the load capacity of the truss of members filled with concrete is higher by 17.5% than the truss of the hollow members. machacet et al.[14] studied numerically the warren truss with concrete deck slab and determined the longitudinal shear distribution between the concrete and steel form elastic up to plastic and proved that, the non-linear longitudinal shear distribution, requisite for the design of shear connectors. huang et al. [15] obtained experimental results agreed with chan et. al. [13] and machacet et. al. [14] findings and they found the concrete inside the chords rises the strength and the rigidity of the joint. xu et al. [16] investigated the influence of the high-to-span ratio and the existence of concrete infill on the flexural behaviour of curved cfst truss girders and straight cfst truss girders. they found that the stiffness and the ultimate load of curved cfst truss girder are higher than the straight cfst truss girders and the curved hollow truss girders. similar findings were obtained by [17-20]. all the previously mentioned researches were concentrated on cfst truss girders without taking into consideration the existence of the concrete deck slab. only limited researches investigated the structural behaviour of cfst truss girders with a concrete deck slab. han et al. [21] constructed a cfst truss girder specimen consists of two upper cords and a lower chord as well as a deck slab and compared the results with cfst truss girders without deck slab. the top and bottom chords were filled with concrete. they concluded that the ultimate load of the cfst truss with a concrete slab is higher than the ultimate load of cfst truss girders only, and a hollow steel tube truss girder. hu et al. [22] studied the flexural behaviour of two concrete filled steel tube truss composite beams experimentally and analytically. one of the specimens has transverse braces and the other has diagonal and transverse braces. the load capacities, the deflection shapes, the failure modes, the strain responses were evaluated. it was found that the failure mode of the specimen which has diagonal braces was surface plasticity at the lower chord and the failure mode of another specimen was surface plasticity at the top chords, local buckling, and weld cracks. the specimen of diagonal braces can develop a shear transmute mechanism between the upper and the lower chords, this led to larger load capacity, stiffness, and ductility than the other specimen. this study extended the knowledge on the flexural behaviour of cfst truss girders with a reinforced concrete deck slab. the experiments were carried out on three truss girders. the test parameter was the location of the concrete-filled tube and its existence. the deflection, load capacity, failure modes, and slip between the concrete slab and steel tube were reported. figure 1 details of the test specimens. nomenclature cfst concrete filled steel tube. l.p. limestone powder c.a. coarse aggregate pu the ultimate load f.a. fine aggregate s.p superplasticizer ki stiffness u mid-span deflection kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 169 figure 2 cross-section of the test specimens. 2. experimental work 2.1. specimens and materials details three specimens of composite concrete-steel truss girders were designed as shown in figs. 1 and 2 and tested experimentally. square steel tubes with dimensions of (100˟100˟3.8) mm were used to construct the chords as well as the first and the last braces of the truss specimens while the diagonal and vertical braces were constructed by using square steel tubes with dimensions of (80˟80˟2.8) mm. the braces and the chords were welded (electrode-welding type e6013) together in a manner illustrated in fig. 1. the upper chord of the three trusses was composite with concrete deck slabs 2600 mm long and 400 mm wide. all the slabs were constructed with a (75) mm thickness and reinforced by ф8 mm steel bars. shear connector channels (u50x25) with a length of 80 mm and 5 mm in thickness were used to connect the slabs with the chords distributed at a distance of (120) mm centre to the centre along the slab length. the properties of the steel types used in this study are shown in table 1. table 1 steel sections and bars properties [23]. steel section yield stress (fy) (mpa) ultimate stress (fu) (mpa) tube (100*100*3.8) 328.2 372 tube (80*80*2.8) 382.9 435.4 channel (u50x25) 344.4 487 bar (φ 8 mm) 401.5 598.8 self-compacting concrete (scc) was utilized to fill the tubes and to cast the deck slabs to avoid the difficulty of the compaction when using normal concrete. the production of such concrete was according to the requirements of the european federation of specialist construction and concrete (efnarc) specifications bibm et. al. [24]. the tests performed for this purpose are showing in table 2. the steel tubes were filled by scc with a (50 mpa) strength grade while the deck slabs were cast by using scc with a strength grade of (60 mpa). the concrete mix proportions of the scc used are shown in table 3. table 2 results of the test of fresh concrete method mix symbol limitations [24] m50 m60 slump flow (d) mm 674 665 650 – 800 (t50 cm) sec. 3.5 4.4 2 – 5 v-funnel (tv) sec. 8.4 9.2 6 – 12 l-box (br) 0.82 0.86 0.8 – 1.0 table 3 concrete mixes proportions mix cement (kg/m3) f.a. (kg/m3) c.a. (kg/m3) l.p. (kg/m3) s.p (kg/m3) water/cement (kg/m3) m50 328.7 489.4 533.2 65.7 (1.5%) 0.42 m60 336.3 500.8 545.6 67.3 (1.75%) 0.36 as shown in table 4, in the (d60t50b50s12) truss, both chords were filled with concrete. for the (d60t0b50 s12) truss, only the lower chord was filled with concrete while the upper chord remained hollow. in the case of the (d60t0b0 s12) truss, both chords were kept hollow. table 4 parameters of the test specimens id specimen compressive strength fcu (mpa) deck slab cft top chord cft bottom chord 1 d60t50b50s12 60 50 50 2 d60t0b50s12 60 0 50 3 d60t0b0s12 60 0 0 2.2. manufacturing process the manufacturing process of the specimens is shown in fig. 3, which can be summarized as follows: i. closing the first end of chords by welding a 4 mm thick steel plate, while the other end was covered to prevent the evaporation of the water from the fresh concrete. ii. the concrete was poured into the chords while the trusses were placed vertically as shown in fig. 4. the cfst specimens were then left for 10 days to harden the filling concrete iii. to cast the deck slab, the moulds were cleaned and oiled first then, the steel reinforcement was placed inside the moulds and the concrete was poured and levelled. this stage was demonstrated in fig. 5. 170 kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 figure 3 manufacturing proses. figure 4 cast of cfst truss girder. figure 5 cast of the concrete deck slab. 2.3. testing procedure the specimens were tested under a monotonic load, by utilizing a hydraulic machine, to test the flexural response of this type of composite trusses. the load was placed in the mid-span and the girders were simply supported in addition to the lateral support to prevent the specimen from twisting as shown in fig. 6. to measure the vertical deflection and the slip between the concrete deck slab and the steel tube of truss girder, four linear variable differential transformer (lvdt) were utilized. for vertical deflection measurement, one of the lvdts was placed at the mid-span and the other one was at the third of the span attaching the bottom face of the bottom chord. the remaining two were used to measure the slip of the deck slab at the end and one-third of the specimen slab as shown in fig. 6. figure 6 testing of cfst composite with a concrete deck slab. 3. results and discussions 3.1. load-deflection relationship the deflections were recorded at mid-span and one-third of the span for every loading increment of the three tested specimens. the results illustrated in fig. 7 and table 5 revealed that there is a reduction in the ultimate load of the tested specimens d60t0b50s12 and d60t0b0s12 compared to that of d60t50b50s12 by 6.68% and 39.59% respectively. the reason behind this reduction is the existence of the hollow tubes in these trusses. the buckling of the bottom chord’s steel tube at the supports was observed in the tested specimen (d60t0b0s12) resulted in a significant decrease in the ultimate load. while the specimen (d60t0b50s12) showed buckling of the top chord’s steel tube at the midspan. the resistance to the compressive and the tensile forces of the top and the bottom chords increases when the tube was filled with the concrete. this prevents the buckling inward in the top chord and restrains the pinching in the bottom chord huang et. al. [8]. it was previously agreed that the strength of cfst exceeds that of the hollow tube chan et. al. [13]. fig. 8 shows the deflection shape of the specimens at a different load level (0.25pu, 0.5pu, 0.75pu, 0.9pu, and pu). this figure indicated that the deflection increases with the progress of loading stages, especially in the final stages, as the relationship is approximately linear until the yield load is reached, then it becomes nonlinear. the lowest value of the stiffness was observed at the d60t0b0s12 specimen and the highest value was at d60t50b50s12 as shown in table 5. table 5 load capacity and deflection for the tested specimens. specimen pu (kn)  (mm) ki (kn/mm) d60t50b50s12 525.6 17.19 60.2 d60t0b50s12 490.5 17.42 46.3 d60t0b0s12 317.5 13.92 37.3 kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 171 figure 7 load-deflection relationship of specimens d60t50b50s12, d60t0b50s12 and d60t0b0s12 at the mid-span. 3.2. the failure pattern it was found that the failure mode was dominated by the tensile fracture of the lower chord when the ratio of the brace to the strength of the chord is exceeding or equivalent to 0.8 and the span/depth ratio of the shear is exceeding or equivalent to 4.8. on the other hand, for the other cases, the dominated failure mode was the joint failure according to xu et al. [16]. fig. 9 shows that, for the specimen d60t50b50s12, the failure mode was the joint shear failure (weld fracture) where the ratio of the shear span to depth was (3.075). this result agreed with that obtained by huang et al. [8]. in the case of the specimen d60t0b50s12, the failure mode was surface plasticity failure as shown in fig. 10. this attributed to the absence of the concrete in the top chord (hollow). fig. 11 indicated that d60t0b0s12 shows a plasticity failure at the supports as the bottom chord was hollow. (a) d60t50b50s12 (b) d60t0b50s12 (c) d60t0b0s12 figure 8 deflected shape of the tested specimens. 172 kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 figure 9 failure mode of specimen d60t50b50s12. figure 10 failure mode of specimen d60t0b50s12. figure 11 failure mode of specimen d60t0b0s12. weld fracture surface plasticity surface plasticity kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 173 figure 12 load-slip and longitudinal slip of specimen d60t50b50s12. figure 13 load-slip and longitudinal slip of specimen d60t0b50s12. figure 14 load-slip and longitudinal slip of specimen d60t0b0s12. 174 kareem mohammed alnebhan , muhaned a. shallal /al-qadisiyah journal for engineering sciences 13 (2020) 167–174 4. conclusions from this study, the following conclusions can be reported as: 1. the steel tubes of the upper chord filled by concrete prevent surface plasticity failure of the upper chord under loading and increase the ultimate load by 6.68 %. also, filling the lower chord with concrete prevents the surface plasticity failure in the supports zone and caused an increase in the ultimate load by 39.59 %. 2. the slip at the end of the specimen of two chords filled with concrete is less by 71% than the end slip of specimen of hollow top chord and higher by 46.8 % than the specimen of two hollow chords. references [1] r.p. johnson, composite structures of steel and concrete: beams, slabs, columns and frames for buildings, john wiley & sons, 2018. 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[18] z.-q. fu, b.-h. ji, w. zhu, h.-b. ge, bending behaviour of lightweight aggregate concrete-filled steel tube spatial truss beam, journal of central south university, 23(8) (2016) 2110-2117. [19] y.-h. huang, a.-r. liu, j.-y. fu, y.-l. pi, experimental investigation of the flexural behavior of cfst trusses with interfacial imperfection, journal of constructional steel research, 137 (2017) 52-65. [20] w. zhou, y. chen, k. wang, s. han, f.p. galarza, experimental research on circular concrete filled stainless steel tubular truss, thin-walled structures, 117 (2017) 224-238. [21] l.-h. han, w. xu, s.-h. he, z. tao, flexural behaviour of concrete filled steel tubular (cfst) chord to hollow tubular brace truss: experiments, journal of constructional steel research, 109 (2015) 137-151. [22] b. hu, j. wang, experimental investigation and analysis on flexural behavior of cfsttc beams, thin-walled structures, 116 (2017) 277-290. [23] i. astm, astm e8/e8m-16a: standard test methods for tension testing of metallic materials, west conshohocken, pa, usa: astm international, (2016). [24] c. bibm, e. ermco, efnarc, the european guidelines for self-compacting concrete. specification, production and use, (2005). article al-qadisiyah journal for engineering sciences 13 (2020) 046–054 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: sajid.kamil@uomisan.edu.iq (sajid k. zemam) https://doi.org/10.30772/qjes.v13i1.648 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. developing sustainable concrete compaction using a proposed multivibration technique sajid kamil zemam a* a civil engineering department, engineering college, university of misan, amarah, iraq. a r t i c l e i n f o article history: received 10 january 2020 received in revised form 24 february 2020 accepted 28 february 2020 keywords: sustainable construction concrete compaction revibration multi-vibration silica fume vibration energy a b s t r a c t this study seeks to develop a sustainable construction technique based on the introduction of a specific method for improving concrete compressive strength through a proposed multi-vibration compaction method. an experimental program is performed to evaluate the effect of the proposed compaction technique on fresh silica fume concrete undergoing the initial setting. multi-vibration intends to minimize concrete production cost because it upgrades the compressive strength of the same materials with better utilization of the vibration energy required for compaction. the collected experimental data presented assign relationships among vibration duration, vibration cycles or phases, and compressive strength upgrading of single vibrated, revibrated, and multi-vibrated specimens for analysis and discussion. this study shows that multi-vibration phases, rather than single vibration or revibration techniques, are powerful techniques for improving concrete compressive strength. the results indicated that the existence of an optimum multivibration mode was dominated by phase number and vibration duration and confirm the reliability vibration overall time duration recommended by aci 309 which relates to a single vibration time limit to be considered in the case of multi vibration technique. multi-vibration mode 8 (subjected to three vibration phases 10, 20, and 30 sec ) has the best effect for the considered mixtures among the specific vibration modes. the maximum improvement ratio is 1.25, which is associated with the plastic mixture. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction sustainable construction is the creation and responsible management of a healthy built environment based on resource efficiency and ecological principles [1]. hence, sustainable construction, which includes design, tendering, site planning, organized material selection, recycling, and waste minimization, could also be described as a subset of sustainable development [2-4]. a mass of freshly placed concrete is usually honeycombed with entrapped air. if allowed to harden in this condition, the concrete will be nonuniform, weak, porous, and poorly bonded to the reinforcement. it will also have a poor appearance. the mixture must be consolidated if it is to have the properties normally desired and expected of concrete [5]. multi-vibration intends to minimize concrete production cost because it upgrades the compressive strength of the same used materials with better utilization of the vibration energy required for compaction. fig.1 shows the themes of sustainable development [6]. a researcher stated that the re-vibration technique can ensure strength improvement for the same liner concrete mix which in turn ensuring the cost effectiveness of the construction [7]. this research seeks to develop a sustainable construction technique based on introducing a specific compaction method to improve the compressive strength of concrete precast units through a proposed multi-vibration technique. compaction is the technique of inducing optimal http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 47 particle arrangement in mixed concrete or mortar, during casting, by reducing voids through vibration. by using chemical admixtures, consistencies requiring reduced compaction effort can be obtained with low water content to improve concrete quality provided that the mixtures are consolidated sufficiently. if the mixtures are compacted inadequately, the quality of the hardened concrete degrades drastically [5]. this research is an attempt to investigate the compressive strength of uniform, plastic, and highly plastic concrete made using silica fume as supplementary cementitious material for the partial replacement of cement. the replacement ratios in this study are 5%, 10%, and 20%. the benefits of silica fume as a material that could increase concrete strength can be maximized by using smart vibration modes in accordance with concrete workability. ornowski [8] conducted a classical study on the effect of the continuous vibration of concrete. many other works have focused on vibration and revibration as appropriate compaction processes and investigated various parameters [9-12]. however, these studies remain limited and have interested researchers in the present. krishna and rathish investigated the revibration effect on compressive strength and density with different w/c ratios, lag intervals, and revibration cycles [13]. kassim examined the effects of revibration on retarded concrete compressive strength at late lag intervals based on initial and final setting times. various time lag intervals and cement retardant dosages are also considered [14]. the multi-vibration concept is adopted to identify the relationship between vibration duration, vibration phase, and compressive strength upgrading of single vibrated, revibrated, and multi-vibrated specimens. the test results obtained will be reviewed to illustrate development during various vibration modes. this study confirmed that the multiphase and revibration technique is applicable as a powerful compaction method in concrete production. the multi-vibration technique may be a necessary and complementary step for concrete production. the optimum multi-vibration mode should be determined during trial batches. figure. 1 themes of sustainable development [6] 2. experimental investigation 2.1. material properties the details of the constituent material properties are described below. 2.1.1. binder materials portland cement portland cement (type i) used in this work was manufactured by an iraqi factory and was designated as tasloga cement. it was stored in airtight sheets to eliminate the effects of humidity. physical property and chemical analysis indicated that the cement used is conformed to astm c150-04 [15]. silica fume mega add ms (d), a micro silica fume [16] which conforms to the chemical and physical requirements of astm c1240-03 [17], was used throughout the current study. it is a new-generation concrete additive in gray powder form, is a by-product of highly active pozzolanic material, and is ready to be used. this fume was used at 5%–20% by mass of cementitious materials as partial replacement for concrete structures that require high strength or considerably reduced water permeability [18]. 2.1.2. fine and coarse aggregates locally available natural sand with smooth texture, round particles with a maximum size of 4.75 mm, and yellowish-brown color were used for concrete batches. the used fine aggregates conformed to the iraqi specification no. 45/1984[19], astm c33-03[20], and b.s. 882:1992[21]. locally available washed crushed coarse gravel with a maximum size of 18 mm was used. its grading was within the iraqi specification requirements no. 45/1984[19]. various dosages of silica fume that are 0.5%, 10%, and 20% (designated as a, b, and c groups respectively) were adopted. plastic, highly plastic, and uniform mixtures were used (slump; 60, 90, and 110 mm) to control the workability effect of fresh concrete. this is an important consideration in the selection of the compaction method for concrete precast production[5]. the material proportions of the investigated sets are listed in table 1. concrete mixtures are proportioned to provide the workability needed during construction and the required properties in the hardened concrete. the prepared samples, used in the present study, were divided into three batches. in each batch, one sample was used as a reference specimen. the adopted mixing procedure is according to astm specification c305-65 [22] for mixing mortars. all batches were mixed in a 0.5 cubic meter capacity portable mixer. specimens with dimensions of 100 mm × 100 mm × 100 mm were used [23]. they were cured in a moist curing pool. a hydraulic, 2000-ton capacity, compressive testing device was used in this study; the testing load was applied monotonically in increments (rate of loading about 10 kg/sec). the increments were decreased as the load reaches the failure load. an ultrasonic and schmited hammer was employed to confirm the predicted results as shown in plate 1. 3. vibration procedure the vibration consists of subjecting freshly placed concrete to rapid vibratory impulses which liquefy the mortar and drastically reduce the internal friction between aggregate particles. while in this condition, concrete settles under the action of gravity (sometimes aided by other forces). when vibration is discontinued, friction is re-established. a vibrating table normally consists of a steel or reinforced concrete table with external vibrators rigidly mounted to the supporting. the table and the frame are isolated from the base by steel springs, neoprene isolation pads, or other means. the electrical asynchronous motor table vibrator model type vv03n/2 [24] shown in plate 2 was used. in the model, two ends of the shaft were enhanced with different weights. the details of the specific features of the vibrator that make it suitable for use are shown in table 2. 48 sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 plate 1. test settings table 1. experimental methodology no. mix type cement kg/m3 silica fume kg/m3 binder kg/m3 sand kg/m3 gravel* (kg/m3) water (kg/m3) w/binder (%) superplastizer (kg/m3) superplastizer/ binder p/b (%) silica/binder, s/b (%) binder:sand: gravel slump (mm) mixture workability ** 1 a 784 41.3 825 1031 1650 330 40 8.25 0.1 5 1:1.25:2.0 110 uniform 2 b 792 88 880 1100 1760 352 40 8.8 0.1 10 1:1.25:2.0 90 plastic 3 c 704 176 880 1100 1760 440 50 8.8 0.1 20 1:1.25:2.0 63 high plastic table 2. electrical motor shaking table characteristics type vv03n/2 maximum centrifugal force in kn 1.18 power source voltage rating in volts 230/400 maximum current rating in amperes 0.57/0.33 rotation speed in revolutions per minute (rpm) 3000 rated power, output power, in kw 0.17 power source frequency rating (hz) 50 phase angle of the electric motor 0.74 max. amb. 40 weight (kg) 5.8 plate 2. vibration table (model vv03n/2) nine vibration modes were used. these modes varied in terms of vibration cycles or phases and duration. samples were subjected to different cycles of vibration, whereas control specimens were consolidated only once. other samples were subjected to two or three vibration phases. two approaches were considered to determine the duration of each vibration iteration. the first approach was based on the acceptable limit (20 s) set by aci 308, whereas the second approach was based on an extreme duration (60 s). the period between successive vibration phases was 20 min. fig. 2 illustrates the phase number and duration time of each vibration mode, table 3 explains the specimen’s description concerning vibration duration. no. g r o u p v ib r a ti o n m o d e s p e c im e n s e ts vibration time (sec) 1 st p h a se 2 n d p h a se 3 r d p h a se a c c u m u la ti v e ti m e 1 a mode (1) a1 60 60 2 mode (5) a2 20 20 3 mode (6) a3 20 20 40 4 mode (7) a4 20 20 20 60 5 mode (8) a5 10 20 30 60 6 mode (9) a6 30 20 10 60 7 b mode (1) b1/1 60 60 8 mode (2) b1/2 60 60 120 9 mode (3) b1/3 60 60 60 180 10 mode (4) b1/4 60 40 20 120 11 mode (5) b2 20 20 12 mode (6) b3 20 20 40 13 mode (7) b4 20 20 20 60 14 mode (8) b5 10 20 30 60 15 mode (9) b6 30 20 10 60 16 c mode (1) c1/1 60 60 17 mode (2) c1/2 60 60 120 18 mode (3) c1/3 60 60 60 180 19 mode (4) c1/4 60 40 20 120 20 mode (5) c2 20 20 21 mode (6) c3 20 20 40 22 mode (7) c4 20 20 20 60 23 mode (8) c5 10 20 30 60 24 mode (9) c6 30 20 10 60 note: time between success phases is 20 min sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 49 mode 1 mode 2 mode 3 mode 4 mode 5 mode 6 mode 7 mode 8 mode 9 figure 2. phase number and duration time of each vibration mode fig. 3 depicts the vibration mode durations and cumulative durations for all specimen sets subjected to one and/or two and/or three phases of vibration. 4. results and discussion the results presented in table 4 show the phase sequence of the vibration process is rather important than the cumulative vibration duration. this can be seen clearly in the results of the control mode of compressive strength compared with other modes achieved with different vibration phases. the results for the tested specimens are presented in tables 4-6. each table presents comparisons with assigned controlled specimens. table 4 shows that the supplementary vibration energy effects are varied within customary limits according to the aci 309 committee. specimens of unique vibration phases are assigned within different groups as controlled specimens and are vibrated for 20 sec only (a2, b2, and c2). the assigned specimens are referred to under revibration and multivibration phases of the average time (20 sec) and various accumulative times (various vibration energy). specimens in different groups vibrated under mode 8 exhibited high strength upgrading with a maximum improvement ratio of 1.25, which is associated with the high plastic mixture. such a low flowability degree is the result of the optimum cement water ratio in the mixture. the mixture is more stable with minimized segregation during the compaction process. table 5 shows that different specimens subjected to the same supplementary vibration energy were considered. also, the specimens subjected to 60 s of vibration time were designated as the control specimens (a1, b1/1, and c1/1) to be referenced to those subjected to revibration and multi-vibration for a cumulative duration of 60 s (supplementary vibration energy is equal). the same previous vibration mode (mode 8) produced 0 10 20 30 40 50 60 70 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 40 50 60 70 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 40 50 60 70 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 40 50 60 70 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 1 2 3v ib ra ti o n d u ra ti o n ( se c ) vibration phases 0 10 20 30 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 0 10 20 30 1 2 3 v ib ra ti o n d u ra ti o n (s e c ) vibration phases 50 sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 specimens with high strength upgrading ratio. the best improvement was observed in the mixture of uniform consistency (a). this mixture contains micro bubbles since the further agitation of the mixture by sustainable vibration process caused small entrapped air bubbles to rise to the surface while large air bubbles are more easily removed during the early vibration process than small ones because of their greater buoyancy. the strength of this specimen increased to 1.222, which exceeded 1.125 for the same specimen (a5) in table 4 for the variable supplementary vibration energy of specimens under the 20 s single-phase vibration time. as inferred from the results in tables 4 and 5, although the cumulative vibration time was 60 s, the strength upgrading differed, thereby reflecting the effect of multivibration phases. table 6 shows the effects of extreme supplemental vibration energy. it provides a comparison of the specimens subjected to revibration and multivibration phases with an average duration of 60 s and different cumulative vibration times (60–180 s) with control specimens subjected to an extremely unique vibration phase for 60 s (b1/1, and c1/). the comparison of the strength upgrading of control specimens with that of specimens subjected to various supplemental vibration energies within customary limits according to aci 309 is shown in table 4. the table indicates that the slight increase in compressive strength was because of the extreme vibration in different modes, which was useless in terms of supplementary vibration energy, this finding confirms the negative effect of over vibrating and could be contributed to getting undesirable deformation in initial bonding of early developed cementitious gels. fig. 4 illustrates the comparison among the effects of single, revibration, and multi-vibration phases on the tested sets. the strength of the specimens subjected to the powerful three-phase multi-vibration mode for 20 s per phase, which was within the recommended vibration duration limits of aci 309, increased by 1.074, 1.088, and 1.1 relative to those of the specimens subjected to a single vibration mode for the b, a, and c series as shown in fig. 6-a. these results confirm the reliability vibration time duration recommended by aci 309 which relates to a single vibration time limit to be considered in the case of multi vibration technique. the strength upgrading ratios of the specimens subjected to revibration with a regime duration of 60 s were 1.134 and 1.129 with respect to those of the specimens subjected to the single vibration mode for the b and c series, respectively. this observation confirmed that for long vibration duration two phases vibration of two iterations assigned as a more efficient technique than three phases -vibration compaction, as shown in fig. 6-b. table 4. comparison of revibration and multi-vibration phases with an average duration of 20 s and different cumulative times with a single phase of 20 sec no. specimen sets vibration mode vibration phase order average time of vibration phase (sec) accumulative time of all phases fcu (mpa) fcu* (compressive strength of control specimen, mpa) rg = fcu/fcu* 2 a2 mode (5) 1 20 20 58.2 a2= 58.2 1.00 3 a3 mode (6) 2 20 40 60.8 1.05 4 a4 mode (7) 3 20 60 63.3 1.09 5 a5 mode (8) 3 20 60 65.5 1.13 6 a6 mode (9) 3 20 60 61.5 1.06 11 b2 mode (5) 1 20 20 60.3 b2= 60.3 1.00 12 b3 mode (6) 2 20 40 63 1.05 13 b4 mode (7) 3 20 60 64.7 1.07 14 b5 mode (8) 3 20 60 66.7 1.11 15 b6 mode (9) 3 20 60 63.3 1.05 20 c2 mode (5) 1 20 20 53.8 c2=53.8 1.00 21 c3 mode (6) 2 20 40 56 1.04 22 c4 mode (7) 3 20 60 59.2 1.10 23 c5 mode (8) 3 20 60 60.6 1.13 24 c6 mode (9) 3 20 60 59.5 1.11 table 5. comparison of revibration and multi-vibration phases with an average duration of 20 s (constant accumulative time, 60 s) with respect to a single phase of 60 s no. specimen sets vibration mode vibration phase order average time of vibration phase (sec) accumulative time of all phases fcu (mpa) fcu* (compressive strength of control specimen, mpa) rg = fcu/fcu* 1 a1 mode (1) 1 60 60 53.6 a1= 53.6 1.00 4 a4 mode (7) 3 20 60 63.3 1.18 5 a5 mode (8) 3 20 60 65.5 1.22 6 a6 mode (9) 3 20 60 61.5 1.15 2 b1/1 mode (1) 1 60 60 61.7 b1/1=61.7 1.00 13 b4 mode (7) 3 20 60 64.7 1.05 14 b5 mode (8) 3 20 60 66.7 1.08 15 b6 mode (9) 3 20 60 63.3 1.03 6 c1/1 mode (1) 1 60 60 53.1 c1/1=53.1 1.00 22 c4 mode (7) 3 20 60 59.2 1.11 23 c5 mode (8) 3 20 60 60.6 1.14 24 c6 mode (9) 3 20 60 59.5 1.12 sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 51 table 6. comparison of revibration and multi-vibration phases with average durations of 60 s (various cumulative time with respect to a single phase of 60 s) no. specimen sets vibration mode vibration phase order average time of vibration phase (sec) accumulative time of all phases fcu (mpa) fcu* (compressive strength of control specimen, mpa) rg= fcu/fcu* 1 b1/1 mode (1) 1 60 60 61.7 b1/1= 61.7 1 2 b1/2 mode (2) 2 60 120 70 1.13 3 b1/3 mode (3) 3 60 180 62.3 1.01 4 b1/4 mode (4) 3 40 120 66.7 1.08 5 c1/1 mode (1) 1 60 60 53.1 c1/1= 53.1 1 6 c1/2 mode (2) 2 60 120 60 1.13 7 c1/3 mode (3) 3 60 180 56.7 1.07 8 c1/4 mode (4) 3 40 120 55.4 1.04 figure 3. vibration mode durations and cumulative durations for all figure 4. variations in the compressive strength of specimen sets in all vibration modes figure 5. variations in the cumulative applied vibration time of all specimen sets in all vibration modes 0 20 40 60 80 100 120 140 160 180 200 d u ra ti o n ( se c ) specimens sets first phase duration second phase duration third phase duration accum. time 52 sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 50 52 54 56 58 60 62 64 66 68 70 1 2 3 c o m p re ss io n s tr e n g th ( m p a ) vibration phase number c series d series a. (vibration phase time = 20 s) b. (vibration phase time = 60 s) figure 6. effects of single, revibration, and multiphase vibration on compressive strength figs. 6 and 7 illustrate the effect of the interaction of the silica fume with the vibration response on the admixture compressive strength and mixture workability. the figures show that strength decreased when a high silica fume ratio (20%) was adopted and mixture workability tended to be plastic consistency. the constant supplementary vibration energy was verified in fig.7, which shows the effect of silica fume ratio on compressive strength under vibration modes of equal overall cumulative vibration time (60 s) but different phases (10, 20, and 30) with an average duration of 20 s. specimens with 10% silica fume were characterized by a mixture of plastic workability and were highly responsive to different vibration modes, with mode 8 presenting high effectiveness and its compressive strength increased to 66.7 mpa from 61.7 mpa under the single vibration mode (mode 1). figure 7. relationship of silica fume ratio and compressive strength on vibration modes with constant cumulative vibration time and different phase periods the effects of single, revibration and multi-vibration modes (modes 5, 6, and 7) on a series of specimens with different silica fume ratios (5%, 10%, and 20%) are illustrated in fig. 8. the multi-vibration mode (mode 7) had a stronger effect than the revibration mode (mode 6). fig. 8 shows the 10% silica fume ratio was the ratio with the best compatibility with the three-phase multi-vibration mode. this observation could be related to the consistency improving in present of silica particles. figure 8. relationship of silica fume ratio and compressive strength under single, revibration, and multi-vibration modes fig. 9 shows the improvements in the concrete strength of all tested groups as a function of different vibration modes. this improvement could be ordered as modes 8, 7, and 9 in accordance with the efficiency of strength upgrading. among these modes, mode 8, which involved three steps of vibration with linearly tapered phase time increments (10, 20, and 30 s), was the best. the macro views of intersections in the specimens were obtained. the equivalent radii of voids within concrete particle structures ranged between 40 and 88 μm and were 55 μm on average. the main objective of vibration, re-vibration, and multi-vibration is to expulsion of air bubbles out of the concrete matrix. in fact, this process can mitigate the voids in the microstructure of concrete and increases the density of concrete. a researcher stated that the re-vibration enhanced the compressive strength and increases the density [7]. a typical view is provided in a plate (3). plate (4) illustrates the concrete surface texture within specimens from various groups in compaction under mode 5 to those under the unique vibration phase (mode 1). the concrete surface texture and overview surface color changed as a function of the silica fume ratio. 50 52 54 56 58 60 62 64 66 68 70 1 2 3 c o m p re ss io n s tr e n g th ( m p a ) vibration phase number a series b series c series 50 52 54 56 58 60 62 64 66 5 10 15 20 c o m p re ss io n s tr e n g th ( m p a ) silica fume ratio (%) mode 5 mode 6 mode 7 50 52 54 56 58 60 62 64 66 68 5 10 15 20 c o m p re ss io n s tr e n g th ( m p a ) silica fume ratio (%) mode 1 mode 7 mode 8 mode 9 sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 53 figure 9. effects of vibration modes on the compression strength of different groups (a, b, and c) plate 3. typical laminated view of a differential area of 0.04 mm, specimens b5 a2, mode 5 b2, mode 5 c2, mode 5 b5, mode 8 c5, mode 8 d5, mode 8 plate 4 concrete surface texture within an elementary differential area of 0.0004 mm2 of various tested groups under mode 8 in comparison with those under unique vibration phase (mode 5) 50 52 54 56 58 60 62 64 66 68 c o m p re ss io n s tr e n g th ( m p a ) a ) vibration mode 56 58 60 62 64 66 68 70 c o m p re ss io n s tr e n g th ( m p a ) b) vibration mode 56 58 60 62 64 66 68 70 c o m p re ss io n s tr e n g th ( m p a ) c) vibration mode 54 sajid kamil zemam /al-qadisiyah journal for engineering sciences 13 (2020) 046–054 5. conclusion 1. the multiphase and revibration technique is confirmed to be an applicable powerful compaction method in concrete production. 2. an optimum multi-vibration mode dominated by phase number and vibration duration existence. 3. the optimum multi-vibration mode could be determined during trial batches. 4. concrete specimens with uniform, plastic, and high-plastic workability have different sensitivities to vibration, and plastic mixture has increased response. 5. among the specific vibration modes in this study, the multi-vibration mode designated as mode 8 has the best effect on the considered mixtures. the maximum improvement ratio is 1.25, which is associated with the plastic mixture. 6. the automation of vibration energy consumption is dependent on the duration and phase number of the vibration mode and could be performed as a necessary and complementary step of precast concrete production. 7. the strength upgrading of specimens vibrated in different modes with constant cumulative vibration time differs and thus reflects the effect of the multi-vibration phase. 8. the rational and low increase in compressive strength could be attributed to extreme vibration in different modes and is useless for supplementary vibration energy. 9. the results confirm the reliability vibration overall time duration recommended by aci 309 which relates to single vibration time limit to be considered in the case of multi vibration technique. 10. revibration processes are more efficient than the multi-vibration phase for specimens subjected to vibration regime duration of 60 s. the average strength upgrading ratio was 1.13. 11. the interaction effect of silica fume presence on the compressive strength as enhancing admixture agent and on mixture workability vibration response could be beyond strength reduction of specimens with high silica fume ratios (20%). specimens with 10% silica fume are characterized by a mixture of plastic workability and positive response to different vibration modes. references [1] chrisna du plessisa, "strategic framework for sustainable construction in developing countries", construction management and economics , 25, 67–76, january 2007. [2] langston, c. a. and ding, g. k. c. (eds.) (2001). sustainable practices in the built environment". butterworth heinemann, oxford. [3] samir. m. chassib, sa’ad. f. resan, m. s. gejan, m. j. salih, a. m. hasan, developing sustainable lightweight bubbled ferrocement slab using enhancing cementitious agents, international journal of civil engineering and technology, volume 9, issue 11, november 2018, pp. 749–765 [4] sajid kamil zemam , sa'ad fahad resan, musab sabah abed, “structural characteristics of developed sustainable lime-straw composite, civil engineering journal” vol. 5, no. 12, december, 2019. [5] american concrete associate, (2005) "guide for compaction of concrete" reported by aci committee 309. [6] malik m.a. khalfan. (2002). "sustainable development and sustainable construction": a literature review on c-san d project. department of civil engineering, loughborough university. [7] m.v. krishna rao, p. rathish kumar and n.v.r.c bala bhaskar “effect of re vibration on compressive strength of concrete” asian journal of civil engineering (building and housing), vol. 9, no. 3, p.p291-301, 2008 [8] ornowski, joseph bartholomew, (1937) "the effects of continuous vibration of concrete during initial set" m.sc. thesis, the university of arizona. [9] tuthills l. h. and daviss h. e. "over-vibration and revibration of concrete" aci journal proceedings vol. 10, no.1, sept. 1938. [10] w. larnach, "changes in bond strength caused by revibration of concrete and the vibration of reinforcement", magazine of concrete research, vol. 4, no. 10, 17-21,1952. [11] satjyers d. h. and lee s. f. "the effects of revibration on the properties of portland cement concrete" a s t m proceedings vol. 5 8 ,1956, [12] vollick c. a. "effects of revibrating concrete" aci journal, proceedings vol. 29, no. 9, march 1958. [13] k. roa, r. kumar, and b. bhaskar, "effect of re-vibration on compressive strength of concrete" asian journal of civil engineering (building and housing), vol.9, no.3,291-301,2008. [14] m.m. kassim, "effect of re vibration on early age retarded concrete", high performace structure and materials, issn 1743-3509, vol.124,2012 [15] astm c150-04, “standard specification for portland cement”, vol. 4.1, 2004, pp. 1−8. [16] micro silica fume (megaadd ms(d)) product data sheet [17] astm c1240-2003, “standard specification for use of silica fume as a mineral admixture in hydraulic-cement concrete, mortar, and grout ”, vol. 4.2, 2003, pp. 1−6. [18] national ready mixed concrete association, “what, why and how? supplementary cementitious materials”, concrete in practice, cip 30, usa, 2000. [19] iraqi standards no.45/1984, “aggregate from natural sources for concrete and construction”, ministry of housing and construction, baghdad, 2004. [20] astm c33-2003, “standard specification for concrete aggregates”, vol. 4.2, 2003, pp. 1−11. [21] b.s. 882: 1992, “specification for aggregates from natural sources for concrete”, dec.1992, pp. 1−9. [22] american society of testing and material, "standard practice for mechanical mixing of hydraulic cement pastes and mortars of plastic consistency ", astm c-305, west conshohocken, pa, 2003. [23] b.s. 1881: part 116: 1983, “methods for determination of compressive strength of concrete cubes”, january 1983, pp. 1−8. [24] venanzetti vibrazioni milano manual , milano, italian, 2003. article al-qadisiyah journal for engineering sciences 12 (2019) 220–224 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: antjiren@gmail.com (anteneh geremew) https://doi.org/10.30772/qjes.v12i4.611 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. improving the properties of clay soil by using literate soil for production of bricks anteneh geremew a*, yibas mamuye a a department of civil engineering, jimma university, jimma , ethiopia a r t i c l e i n f o article history: received 18 september 2019 received in revised form 20 november 2019 accepted 05 october 2019 keywords: literate soil brick clayed soil compressive strength water absorption sustainable construction material a b s t r a c t utilization of local accessible materials is an important stage for sustainability nowadays. brick units are the most commonly used construction material around jimma town due to the availability of clayed soil. in comparison with the traditional method, brick produced by small micros un-skill enterprises is mainly specified by less quantity and lower quality the purpose of this study was to improve the properties of clayed soil adopted in manufacturing of masonry brick units using literate soil . in order to achieve this, non-probability sampling technique was used to collect samples from jimma area. the collected samples were then prepared for running different laboratory tests. the samples were formulated through partially replacing literate soil by 5%, 10%, 15% and 20%, respectively. the test results showed that the procedure adopted in this study can produce lightweight brick units without any deterioration in the quality of bricks. the maximum compressive strength value was noted for the brick units formulated with lateritic soil of 15% replacing. the optimum firing furnace temperature was observed at 1000°c for 5hrs. the brick units prepared at this temperature level exhibited the highest resistance to the applied loads. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction ethiopia is one of the fast economic growth in east-africa [1]. due to urbanization of populations living in towns becoming increases day by day; the sustainable living standards in a town constructing lead to increase the cost of concrete production [2].there are small numbers of micro enterprises working in producing clay brick in a traditional way with less quality. they only focused on the external shape of brick units. in jimma area, large deposit of clayed soil and literate soil are available [3]. laterite earth material was considered to be one of the oldest and commonly used building material. it was considered to be one of the most important construction material on the earth surface was widespread [4]. unfortunately, laterite earth construction in developed country is diminishing with the abrupt changes in construction materials [5].good quality brick units can be manufactured using lateritic soil provided that accepted clay material will be added. the use of plastic clayed alone in the production of brick may not be suitable due to shrinkage and warping effect during the drying process [6]. partially substituting clay earth with disbursed unwanted shea has growth scientific enactment of black of earth in decreasing the mass, improving the general performance [7]. appropriateness of the application of biological flavours in brick earth to be established was upgraded competence and continuing. therefore it decreases ecological effect [8] burring the brick units of earth brick need huge amount of power estimated by 24 million tons per year which is one of major causes of environmental defect [9]. a block earth material has a numerous practices on construction industry resources [10]. according to [6], the application of lateritic brick added clay started around 8000 bc in mesopotamia the construction of houses, dams. due to it durability and cost effectiveness, lateritic brick is also considered an excellent sustainable materials in construction and recycling process and can minimized pollution with low carbon emission during the application [11].the application of laterite earth in building construction almost exist http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 221 anywhere in the world especially in third world country.in country like kano, kaduna and other cities in northern nigeria, used of this material is very effective. but it can be noted that laterite earth is also applied in developing countries [6, 12]. in many countries, such as asia and africa, more than two billion peoples are using in building/house construction using lateritic earth and clay products. the application of these material has earned lot of advantages in terms of quality, characteristics and application in construction. additionally, it improve the quality of lateritic earth, additives and remove of one of its contents is also an option [13]. the reduction of energy requirement in the production of brick using lateritic soil is an advantage. it is produced using 5kwh/m3 compared to fired brick and concrete block which consume 1000kwh/m3 and 450kwh/m3 respectively. additionally, lateritic soil structure are easily recyclable without polluting the environment [14]. due to its availability /existence ant where in the world, its application in the environment building is very crucial. it is available in many different composition, so further investigation is added to other material such as clay to produced sustainable structure [6, 15, and 16]. brick extensively adopted building material round jimma town. unlike other than city outside of jimma used most implemented for modern households, pale, ancient houses are intensively built by block partition and pillars. particularly ancient structures brick pillars and partitions were precise exciting which occur today without major failure and attending still current time. the research conducted by [17] showed that the brick produced nearby jimma area were below standard specifications. in addition, small micros are producing clay brick for low cost houses these days in small amounts and with unsatisfactory quality. this in turn gives lower strength and with high water absorbing behaviour. this study has improved the physical properties of the brick by mixing clayed soil with literate soil. this encourages the use of locally available material for the production of brick for affordable and low cost construction of houses. this considers a good opportunity for job creation for the society living around jimma town. 2. materials required and methods 2.1. materials required in order to achieve the objective of this study, purposively sampling techniques was implemented for the lateritic soil samples around jimma town . this clayed soil has high plasticity and collected at depth of 0.5m in order to protect other organic material. the samples was collected using engineering judgement by observing colour texture and index property. 2.2. preparation of brick units the clayed soil utilized for this particular research was selected with high plastic contents. in order to improve the property of the clayed soil, different percentages of laterite soil 5%, 10%, 15% and 20% (through mass) were used and finally uniform mixing was carried until the same colour was obtained. atterberg limit tests was performed on different percentages of lateritic soil added to the clayed soil. water was added for the mixes prepared until suitable consistency, and proper mixing was achieved. the following procedure was used during production of clay-lateritic brick units:  the collected sample were lateritic and clayed soil allowed to drying separately  grinding the samples in small particles until the required sieve size pass.  preparing mix design according to the percentage required and separately by adding the necessary amount of water for different mixes until the favorable of workability is obtained. the mixes were then stored in a cool room for at least of two days until uniform distribution of water attained in the mixture.  before placing; mould was dipped in water in order to prevent sticking and poured the mix in the mould by thrown forcedly by hand until the rough shaped is achived. the excess on the top of mould was removed by thin wire. immediately; the moulded brick was demolded and dried in the sun for a week and finally the bricks were dried in furnace at 1000°c for 5hrs. 2.3. methods and standard testing procedure table 1 shows a summary of test method table 1 summary of test method type of test test method/ designations moisture content aashto t – 265 sieve analysis astm -d422-63 atterberg limits astm -d4318-98 soil grouping astm -d2487-98 specific gravity astm -d854-83 proctor test astm -d698-98 compressive test is 3495 (part i-iii) and is 3346:1980 preparation of samples is 1077:1992 efflorescence is 3495 (part iii) – 1992 3. result and discussion 3.1. engineering properties of lateritic soil and clay soil 3.1.1. identification of engineering properties of lateritic soils. in order to control the quality of the materials, laboratory tests were carried out based on the standard specification. the experiments elaborate to classify to the belongings lateritic earth such as its physical and mechanical possessions and the results obtained are shown in table 2. table 2. geotechnical properties of lateritic soil s/n type of test test method/ designations 1 catalogue aashto a-2-7 uscs cluster sc uscs cluster poorly -graded sands 2 specific gravity 2.37 3 sieve analysis sand content % (4.75 to 0.075mm) 62.4 silt and clay content % (under 0.075mm.) 37.6 4 atterberg’s limits: % liquid limit 78.54 plastic limit 41.19 plasticity index 37.35 5 proctor test optimum moisture content (omc), % 41.56 maximum dry density ( g/cm3) 1.31 6 red literate soil by visual inspection 222 m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 3.1.2. engineering belongings of clayed soil. the experiments elaborate to classify the possessions of the clayed earth such as its physical and mechanical possessions. therefore investigations carried out on the unprocessed clay earth contains sieve analysis, atterberg limit test, compaction test, california bearing ratio and specific gravity and the results obtained are shown in table 3. table 3. geotechnical properties of clayed earth s/n attribute empirical standards 1 catalogue aashto a-2-5 uscs cluster ch uscs cluster soft soil 2 specific gravity 2.485 3 sieve analysis gravel content% (20 to 4.75mm.) 0.533 sand content % (4.75 to 0.075mm) 4.952 silt and clay content % (below 0.075mm.) 94.515 4 atterberg’s limits: % liquid limit 87.42 plastic limit 31.85 plasticity index 55.57 5 proctor test optimum moisture content (omc), % 34.54 maximum dry density ( g/cm3) 1.235 6 red literate soil by visual inspection 3.2. casting of bricks 3.2.1. preparation of mixed clay-lateritic soil as a control of test a clay brick alone was prepared accordingly and shaped based on size of box and allowed to burnet to a furnace oven. additionally to this unlike proportion of laterite earth added 5, 10, 15 and 20%. the blends were set with the pre-determined optimum moisture content values. the size of box of bricks to be casted dimension of 230 x110x70mm non-modular bricks. it’s obvious as per is 1077:1992. the arranged combination was forced into the mould and subsequently removing the mould retained it for sun drying. the prepared sample of bricks was allowed to dry until it reduces moisture content from it. exposing to ventilation to sun drying period approximately a weeks and finally transferring the samples to the furnace oven, where they were burnt at a temperature of 1000oc for 5hrs. sample of bricks was taken out from the furnace oven after that allowed to cool then starting the laboratory testing started after 21 days of curing as per is code. 3.2.2. test methods the bricks were tested as per in is code for finding the physical properties. the burned bricks were cured for 21 days and only after that testing were started. compressive strength, water absorption, efflorescence and thermal conductivity are the tests conducted on the bricks. the experiments continuously conducted as per is 3495 (part i-iii) and as per is 3346:1980. 3.3. discussion of test results clay bricks made with laterite soil were tested for analysing the physical properties of bricks such as atterberg limit test, compressive strength, water absorption, efflorescence and thermal conductivity. 3.3.1. atterberg limit test and workable mixing water contents the results of atterberg limit tests and workable mixing water contents are shown in table 4 and fig. 1 based on standard specification [19, 20]. it can be seen that both liquid and plastic limits have decreased, with increasing of percentage of laterite content. but also the workable mixing water content also decreases with increase percentage laterite. 𝑷𝒍𝒂𝒔𝒕𝒊𝒄 𝑰𝒏𝒅𝒆𝒙 = 𝑳𝒊𝒒𝒖𝒊𝒅 𝒍𝒊𝒎𝒊𝒕 − 𝑷𝒍𝒂𝒔𝒕𝒊 𝒍𝒊𝒎𝒊𝒕 (1) table 4. effect of laterite soil on atterberg limits laterite soil content (%) liquid limit (%) plastic limit (%) plastic index (%) mixing water contents (%) 0 87.42 31.85 55.57 38.98 5 83.54 30.11 53.43 35.49 10 76.25 27.47 48.78 33.47 15 69.05 22.61 46.44 31.19 20 53.77 18.87 34.9 30.09 figure 1. water contents verses percentage of laterite in clay soil 3.3.2. linear shrinkage and density the summary of the results of linear shrinkage, and dry and firing densities are shown in table 5, the shrinkage decreases with increase of the laterite soil contents but decreases in dry density. table 5. effect of laterite soil on linear shrinkage, dry and after furnace densities of clay-laterite laterite soil content (%) linear shrinkage (%) dry density(kg/m3) after furnace oven (kg/m3) 0 11.63 1820 1753 5 10.16 1756 1654 10 9.25 1611 1488 15 8.85 1523 1376 20 6.11 1402 1224 3.3.3. compressive strength of clay bricks with laterite soil compressive strength test result of produced clay-laterite bricks made with different percentages of laterite soil with 0%, 5%, 10%, 15% and 20% are shown below in table 6 and fig. 2. 𝑨𝒗𝒆𝒓𝒂𝒈𝒆 𝒔𝒕𝒓𝒆𝒔𝒔(𝜹) = 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑙𝑜𝑎𝑑(𝐾𝑁) 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑏𝑒𝑑 𝑓𝑎𝑐𝑒(𝑚𝑚2) (2) table 6. compressive strength values of clay-laterite bricks with laterite soil laterite soil content (%) compressive strength or stress, σ (mpa) specification 0 10.76 compressive strength not less than 10 n/mm2 for class designation 100 [18] 5 10.96 10 11.19 15 11.37 20 11.29 m. al-khuzaie, b. al-humeidawi /al-qadisiyah journal for engineering sciences 12 (2019) 214–219 223 figure 2. variation of compressive strength results of clayed bricks with laterite soil the compressive strength of the bricks depends mainly on the density and porosity of the bricks. it is observed that the results of clay bricks with laterite soil show a compressive strength greater than 10 mpa, which belong to class designation 100 as per indian standard specification. all the modified bricks showed higher strength than control bricks. 3.3.4. water absorption as the percentage of laterite soil increases water absorption decrease. the results obtained for the water absorption are shown in table 7 and fig.3. table 7. water absorption test result of produced bricks with claylaterite laterite soil content (%) water absorption (%) 0 16.25 5 15.54 10 14.48 15 13.04 20 11.55 figure 3. variation of water absorption of clay bricks with laterite soil based on the experiment achieved in laboratory for the manufactured bricks made with laterite soil have similar properties obtained as the control bricks. laterite soilclay brick shows lesser water absorption rate as compared to standard specification of the class. 3.3.5. efflorescence efflorescence was determined to find the alkaline salt content in bricks. the test was conducted as per is 3495 (part iii) – 1992. in this experimental work, no noticeable deposit was observed on majority of samples but there is a very thin deposit of salts observed on certain brick parts. 4. conclusion on the basis of experiment outcomes, the resulting was summarizes as follows: the laterite earth soils were classified based on asshto classification system as a-2-7 category with poorly graded gravel and based on the uscs as sc soil groups. the compaction test for the laterite soils yielded mdd and omc with 1.31g/cc and 41.56% respectively. the clay soils were classified based on asshto classification system as a-2-5 category with high plastic clay and based on the uscs as ch soil groups. the compaction test for the clay soils yielded mdd and omc which 1.235g/cc and 34.54% respectively. the density of brick decreases with increase in laterite contents. light weight bricks can thus be produced without any deterioration in the quality of the bricks. modified clay bricks showed increase in compressive strength up to a particular percentage, beyond that point compressive strength decreases. this is due to the less bonding between clay-laterite and lesser density of the modified bricks. water absorption decreases with increase the percentage addition of laterite soil. this is due to the coarser soil particles in bricks; this results in less water absorption. samples of bricks have minor efflorescence content observed on the face of brick. this in turn means that the alkaline salt content in those bricks is lesser. bricks prepared of clay-lateritic combinations also utilized for high resisting capacity for simple structure except for underground structures. more research must be conducted in order to recognise the long-term effects of clay-laterite block on the toughness of bricks and also examine its chemical composition of clay-laterite soil materials. references [1] undp, “ethiopia: country economic brief,” undp ethiop. policy advis. unit, no. 1, pp. 1–15, 2014. 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[16] s. deboucha and r. hashim, “correlation between total water absorption and wet compressive strength of compressed stabilised peat bricks,” vol. 6, no. 10, pp. 2432–2438, 2011. [17] k. getachew and a. mosisa, “laboratory investigation of locally produced clay brick quality and suitability for load bearing element in jimma area, ethiopia alemu mosisa,” int. j. eng. res. technol., vol. 6, no. 5, pp. 809–817, 2017. [18] is-1077, “common burnt clay building bricks -specification,” bur. indian stand., 2007. [19] astm c67-90. (1996). standard test method for the properties of fired clay bricks “annual book of american society for testing and materials’’. [20] ethiopian standards agency (esa). (2011). solid clay bricks, es 86:2001, ethiopian standard, second edition 2001-06-27. template for academica science journal journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 620 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. study on heterogeneously catalyzed transesterification reaction abdullah nizar saeed, university of technology, al senaha street, rusafa baghdad, baghdad, iraq. e-mail: che.80372@uotechnology.edu.iq farah talib jasim al-sudani, university of technology, al senaha street, rusafa baghdad, baghdad, iraq. e-mail: falsudany@yahoo.com received on 8 october 2017 accepted on 28 december 2017 published on 15 march 2018 doi: 10.30772/qjes.v10i4.510 abstract: the commercial process of heterogeneously catalyzed biodiesel production process is in its final steps due to its advantages over the old homogeneously catalyzed one, and in order to provide an economic and fast way to investigate the vegetable oil conversion into biodiesel, a relation between conversion and a parameter that can be easily measured like viscosity is developed in this paper. the variation of viscosity with increasing conversion was proved to be exponential.an equation was developed to predict conversion from dynamic viscosity values based on the experimental data. a conversion of 91% was obtained at 60 o c reaction temperature, 12:1 methanol to oil molar ratio, 600 rpm in 2 hours of reaction time. the method reported in this paper is meant to save time and money since the most widely used chromatography methods are expensive and time consuming. keywords: biodiesel analysis, viscosity, calcium oxide. introduction the continuously rising energy demands and the limited fossil fuel resources have driven the researchers around the world toward the investigation and development of alternative fuels of renewable resources. biodiesel is the term used to refer to a blend of fatty acid methyl esters with significantly lower exhaust emissions than its rival petro-diesel [1]. biodiesel has some notable properties that attracted the attention to it as a promising alternative to petro-diesel like its biodegradability, low toxic emissions especially co2 gas, decent properties of storage and transportation and the fact that it’s derived from renewable resources [2]. biodiesel is derived from vegetable oils by esterification or transesterification of vegetables oils and animals fats[3].during the previous years the dominant process for biodiesel production was homogeneously catalyzed using mainly potassium hydroxide or sodium hydroxide for transesterification and sulfuric acid for esterification, primary alcohols are used to react with oils in both esterification and transesterification processes(mainly methanol for its favorable properties and low price)[4-6].the homogeneously catalyzed process has proven its acceptance, however it comes with its disadvantages like catalysts corrosiveness, mailto:che.80372@uotechnology.edu.iq mailto:falsudany@yahoo.com journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 621 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. soap formation, glycerol phase contamination with catalyst, requirement of large amount of water for biodiesel washing and requirement of energy for biodiesel drying which makes this process time and labor consuming [7-10]. the corrosion and purification steps associated with the homogeneous process were a key factor to the transformation to the more reliable and time conserving heterogeneous process which was reported as the solution to the homogeneous process problems [11,12]. calcium oxide has been reported as a cheap and effective catalyst for the transesterification process of low free fatty acids oils, its resources basically consists of calcium hydroxide or calcium carbonate that can be calcined at different temperatures to obtain calcium oxide of specific properties (basicity, surface area, pore volume, etc..)depending on calcination temperature and time, cao was categorized as a solid basic catalyst with decent reusability with or without regeneration depending on its origin [13-16]. different analytical systems have been utilized for the quantification of fame in transesterification product including thin layer chromatography (tlc), gas chromatography (gc), high performance liquid chromatography (hplc), nuclear magnetic resonance (nmr), ir spectroscopy and gel permeation spectroscopy (gpc) [17]. these systems are very accurate, sensitive and also measure the content of byproduct glycerol as well as the remaining unreacted glycerides (tri di and mono) in the produced fame. however, the on-line application of these systems in a biodiesel production plant is very difficult due to the requirement of sample preparation and usually chemical modification and most of the times the analysis will continue to more than 30 minutes to get accurate results [17]. when triglycerides in vegetable oils are converted to fatty acid methyl esters there will be a remarkable decrease in the value of viscosity, normally from (40-60) cp to (2-8) cp, according to oil’s fatty acid’s profile. since biodiesel is a mixture of different fatty acid methyl ester, each methyl ester will contribute to the overall viscosity of the produced biodiesel [18]. the objective of the current work is to develop a method that is acceptable, cheap and quick to estimate the conversion of triglycerides and quantify the fame content in the product of a heterogeneously catalyzed transesterification process plant. the method is based on the difference in dynamic viscosity values between the fatty acid glycerides and the corresponding fatty acid methyl esters since methyl esters have lower viscosity values than glycerides. the dynamic viscosity value can be determined with not much effort, time and expenses using an on-line viscometer and thus the content of fame will be continuously measured and the process will be monitored. 1. experimental 1.1. materials analytical grade methanol and n-hexane were purchased from rdh , 96% purity calcium oxide was supplied by cdh which is then activated by calcination at 900 o c for 2 hours and sunflower oil was purchased from local market. 1.2. transesterification the experiments were conducted using a 250 ml flask connected to a reflux condenser, a specific amount of oil was added in the flask and when the desired reaction temperature was reached methanol and catalyst are added according to specific methanol to oil molar ratios and stirred at 600 rpm. experiments are carried out with different reaction temperatures, residence times and methanol to oil molar ratios specifically to investigate different oil conversions and reaction products with a broad range of fame content to get a clear idea about how conversion and dynamic viscosity are related. schematic diagram of the system which is composed of a 250 ml flask (batch reactor), 3 way connection, thermometer an a condenser is shown in figure (1) . journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 622 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1.3. fame analysis the fame product samples were analyzed first by gas chromatography using gc-shimadzu 2010 with sp-2840 column and flame ionization detector (fid), samples are first diluted with n-hexane then injected for the analysis. the injector temperature was fixed at 280 o c and the detector temperature was fixed at 310 o c, column oven temperature was raised from 140 o c (hold 1 min) to 160 o c (10 o c/min), 160 o c to 290 o c at a rate of (10 o c/min) (hold 3 min), 280 o c to 300 o c at a rate of (3 o c/min) (hold 11 min) after gc analysis the dynamic viscosities of each of these samples was obtained at 38 o c using a brookefield viscometer which consists of holder for the cylinder sample, spindle, adapter and a water jacket. figure 1: schematic diagram of the system. 2. results and discussion 2.1. xrd analysis xrd analysis of calcium oxide catalyst was carried out to obtain some structural information about it. cao major peaks are clearly indicated in figure (2) and are indexed to cao (card number: 00-037-1497). no peaks of calcium carbonate or calcium hydroxide are present due to strict storage and transportation of the samples (all samples are stored in vacuum sterile tubes). journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 623 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: xrd analysis of catalyst cao. 2.2. bet surface area analysis bet surface area analysis was carried out for the calcium oxide catalyst using the asap 2020. the test result showed a bet surface area of 3.7202 m 2 /g, pore volume of 0.014526 cm 3 /g, pore size equals to 156.1846 o a and an average particle size of 16128.160 o a. 2.3. relation between conversion and viscosity as shown in the figure (3) a relationship between dynamic viscosity and conversion is obtained. the associated increase in conversion with the notable decrease of dynamic viscosity is attributed to the fact that fatty acid methyl esters has much lower viscosity than triglycerides initially present in the oil, this relation seems to be exponential however at conversions higher than 65% it can be seen from figure (2) that conversion started to vary kind of linearly with dynamic viscosity and this may be because the samples contain mainly methyl esters and less glycerides [18]. %conversion= 156.99*e (-0.137μ) (1) μ : dynamic viscosity (cp) at 38 o c equation (1) can be used to estimate glyceride conversion as a function of dynamic viscosity at 38 o c. statistical analysis was carried out using statistica v10.202, analysis showed a level of confidence equals to 95% and a standard deviation of 6.58. observed values of conversion vs. predicted values of conversion are shown in figure (4). the results’ operating conditions are shown in table (1). journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 624 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3: conversion vs. dynamic viscosity. figure 4: experimental vs. predicted data. table 1: details of experiments. conversion % methanol : oil (molar ratio) t ( o c) residence time (h) dynamic viscosity (cp) 91 12:1 60 2 4.17 83 12:1 60 1.5 4.98 72 12:1 60 1 5.12 journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 625 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2.4. methanol : oil ratio alcohol (methanol ch3oh) to oil molar ratio highly affects the transesterification process. experiments were carried at molar ratios of (6:1, 9:1 and 12:1) at 60 o c below the boiling point of methanol for 2 hours, a condenser is used to assure no (or extremely little) methanol loss during the reaction. it is clearly indicated in figure (5) that an increase in this ratio will positively affect the transesterification reaction and that is attributed to shifting the reaction equilibrium toward the forward reaction where glycerides react with alcohol producing more fatty acid methyl esters and resulting in achieving higher conversions. as shown in figure (4) increasing the methanol to oil molar ratio to 12:1 resulted in the highest glycerides conversion however, studies show that the addition of an excessive amount of alcohol will result in decreased conversions due to slower separation of produced glycerol and methyl esters [19]. it is suggested that glycerol is dissolving in the excessive amounts of alcohol (methanol ch3oh) and inhibits the transesterification reaction thus resulting in lower conversions [20-23]. methanol to oil molar ratios higher than 12:1 resulted in lower conversion and thus biodiesel yield. figure 5: conversion(%) vs. methanol:oil (molar). 2.5. effect of reaction time reaction time is a key parameter in the study of transesterification reaction. set of experiments at 12:1 methanol to oil molar ratio carried out at a reaction temperature of 60 o c and kept for (0.5, 1, 1.5 and 2) 83 14:1 60 2 4.98 67 12:1 50 2 6.38 63 9:1 60 2 6.6 52 6:1 60 2 7.98 43 6:1 60 1.5 8.4 38 9:1 60 1 10.55 29 6:1 50 1.5 11.59 21 12:1 40 2 14.79 14 12:1 40 1.5 17 12 12:1 60 0.5 21.5 4 12:1 40 1 25.02 journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 626 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. hours. as shown in figure (6) the conversion of triglycerides into fatty acid methyl ester remarkably increases with time and after 2 hours of reaction time, a conversion of 91% is obtained and increasing the reaction time beyond 2 hours did not affect the reaction which is attributed to catalyst activity, reaction temperature and the high methanol to oil ratio used in the experiments resulting in shifting the equilibrium reaction toward the forward reaction [20]. this result may differ from that reported in the literature because the activity of calcium oxide catalyst highly depends on its origin [13-16]. figure 6: conversion(%) vs. reaction time (h). 2.6. effect of reaction temperature experiments are carried out with (40,50 and 60) o c reaction temperatures at atmospheric pressure using methanol to sunflower oil molar ratio of 12:1 and the reaction was allowed to continue to 2 hours. reaction temperature was maintained constant during the reaction period and measured using a digital thermometer. as indicated in figure (7) , increasing the temperature from 40 o c to 50 o c and then to 60 o c at atmospheric pressure causes a significant rise in glycerides conversion which is expected since the transesterification reaction is endothermic and the temperature was under the boiling point of methanol where reaction temperatures higher than methanol boiling point will cause a reduction in glycerides conversion due to formation of methanol bubbles [24]. figure 7: conversion(%) vs. temperature. journal of al-qadisiyah for engineering science vol. 10, no. 4 issn: 1998-4456 page 627 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. conclusions a cheap and quick method to calculate glycerides conversion and estimating the fame content is developed using viscosity measurements with the aid of gas chromatography analysis. a predicted data with 95% level of confidence was obtained using the developed equation (1). the exponential variation of dynamic viscosity as a function of conversion was proved and it is apparently as a result of tri, di and mono glycerides conversion into methyl ester. it was shown that increasing reaction time after the first 2 hours did not affect the reaction however increasing methanol to oil molar ratio and temperature beyond 12 molar ratio and 60 o c resulted in a decrease in the conversion. biodata abdullah nizar saeed is a m.sc. student at university of technology, al senaha street, rusafa baghdad, baghdad, iraq. farah talib jasim al-sudani is a lecturer at university of technology, al senaha street, rusafa baghdad, baghdad, iraq. references 1. sharma yc, singh b, upadhyay sn. , advancements in development and characterization of biodiesel: a review. fuel, 87, september 2008, 2355-2373. 2. veljković b., stamenković s., todorović b., lazić l., skala u. , kinetics of sunflower oil methanolysis catalyzed by calcium oxide, in,, fuel, 88, september 2009, 1554-1562. 3. basumatary , transesterification with heterogeneous catalyst in production of biodiesel: a review, journal of chemical and pharmaceutical research, 5, 2013,1-7. 4. fukuda h; kondo a; noda h. j. , biodiesel fuel production by transesterification of oils, in,, journal of bioscience and bioengineering., 2001, 92, 405-416. 5. ma f, hanna ma. , biodiesel production: a review, in,, 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research, in,, 2009,33,347–357. 21. cao lc, zhang sc. , production and characterization of biodiesel derived from hodgsonia macrocarpa seed oil,appiedl energy, in,, 2010,146,135–140. 22. kafuku g, mbarawa m. , alkaline catalyzed biodiesel production from moringa oleifera oil with optimized production parameters, in,, applied energy,2010,87,2561–2565. 23. anwar f, rashid u, ashraf m, nadeem m. , okra (hibiscus esculentus) seed oil for biodiesel production,in,, applied energy,2010,87,779–785. 24. bateni h, karimi k, zamani a, benakashani f. , castor plant for biodiesel, biogas, and ethanol production with a biorefinery processing perspective, in,, applied energy 2014,136,14–22. article al-qadisiyah journal for engineering sciences 14 (2021) 001–005 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hameed@uobabylon.edu.iq (hameed hussein alwan) https://doi.org/10.30772/qjes.v13i3.710 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. study reaction kinetics of fuel model desulfurization by electrochemical oxidation technique israa mohammed a, hameed hussein alwan a*, ghanim a. n.a auniversity of babylon , college of engineering , chemical engineering , babil , iraq. a r t i c l e i n f o article history: received 3 october 2020 received in revised form 15 october 2020 accepted 19 october 2020 keywords: desulfurization oxidation desulfurization reaction kinetics a b s t r a c t the model fuel (heptane contained 2500 ppm from dbt) was desulfurized electrochemically at a constant current (300 ma), in which the process consists two steps; the first step is electrochemical desulfurization by using an electrochemical cell contains two graphite electrodes immersed in electrochemical cell; the cell contains model fuel, hydrogen peroxide as oxidation agent, 0.106 m is nacl to enhance electrolyte electrical conductivity. the investigation was at different operation parameters; temperature range (40-50-60 °c), stirring time (10-20-30-40-50) min, while the second step is extraction with acetonitrile. the results show final sulfur concentration decreased when increasing time at the same temperature for example. kinetics parameters calculation shows that electrochemical desulfurization ecd reaction follows pseudo 1st order reaction, the rates constant of reaction are 0.0175, 0.0191 and, 0.0193 at temperatures 40, 50, and 60 °c, respectively, while activation energy equal 4.433 kj/mol. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction in general, the main source of air pollution is the combustion of sulfur compounds associated with different petroleum productions when used as fuels because off emissions of sulfur oxides (sox), which leads to acid rain and foggy weather, on the other hand, i may cause catalyst poisoning, affects product quality, equipment corrosion and unwanted odors for that. sulfur compounds should be removed from petroleum products tang et al. [1]. thus there a hard environmental consideration for allowable sulfur content with fuel were applied in developed countries, for example, china, in 2014, the maximum sulfur content allowed in fuel was set to be less than 10 ppm [1]. in the united states, the gas contains between 50 to 500 ppm, while iraqi gas oil contains 10,000 ppm ho et al. [2] there are many techniques used to remove sulfur compounds in the oil refining industry, but the common commercial method is the hydrodesulphurization method hds is a chemical process that works with high pressure and temperature in addition to the presence of an amount of expensive catalyst and huge amount of hydrogen alwan et al. [3] , hds method characterized by its high energy consumption mehri et al. [4] , due to the high operating conditions and is ineffective in removing some compounds sulfur, such as benzothiophenes bt, and dibenzothiophene dbt [5, 6], therefore, new methods have been suggested by researchers, such as oxidation, extraction, extraction, and biological sulfur removal [1]. the ecd process, which operates under moderate operating conditions such as air pressure and a normal temperature of less than 80 °c, was discovered and the cost of operation and investment was reduced due to its lack of need for hydrogen in comparison with the hds method zhang et al. [7] , and and can be easily remove (bt, dbt, etc.). ecd process http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i 2 israa mohammed , hameed hussein alwan , ghanim a. n. /al-qadisiyah journal for engineering sciences 14 (2021) 001–005 requires oxidizing agents such as hydrogen peroxide, oxygen ,ozone , proxy acid, and ionic liquid to increase the polarity of the sulfur compounds as a result of donating them with oxygen atoms to facilitate the removal of sulfur compounds later by distillation, adsorption or extraction campos‐martin et al. [8].the ecd consists two steps ; the first step is oxidation sulfur compounds by oxidant agent to formulae have high polarity tang et al. [9] and the second step is extraction the oxidized sulfur compounds by solvent such as acetonitrile [1]. figure 1-oxidation dbt by used per acetic acid in ionic liquid phase [10]. to enhance the reaction rate between compounds founded in different phases (immiscible liquids) and transfer materials from one phase to another phase can be added small amount of phase transfer catalyst ptc. for example, when mixing hydrogen peroxide with acetic acid(ch3coo), it will give per acetic acid (ch3coooh) which is a strong oxidant. dbt can be oxidize to dbto2 when used per acetic acid (ch3cooh) in ionic liquid as shown in fig. 1 [10, 11]. in this work, ecd for model fuel (heptane contains 2500 ppm dbt) by h2o2 at different reaction temperature and time, followed by extraction with acetonitrile. the study was done to investigate the impact of temperature and time in desulfurization. the reaction kinetic parameters were estimated rate constant, reaction order) at studied temperature as well as the activation energy. 2. materials and method 2.1. materials model fuel prepared (heptane contained 2500 ppm from dbt) used as feedstock, analytical grade chemicals are used; hydroxide peroxide h2o2, sodium chloride nacl, glacial acetic acid ch3cooh, acetonitrile ch3cn. all the reagents and solvents used in this study obtained from sigma-aldrich with their standard purity. 2.2. experiment method electrochemical desulfurization ecd done at two steps in which the electrochemical cell apparatus in fig. 2 ; first step is oxidation, the electrochemical oxidative experiments were carried out in electrolysis cell have two electrodes made from graphite at distance 2 cm, while electrolyte is contains0.106 m nacl solution as supporting electrolyte to enhance electrical conductivity for electrolyte , 5ml of hydrogen peroxide as oxidant agent and 2.5 ml of 10% acetic acid solution as phase transfer catalyst . 47 ml of fuel model was added to the cell, the electrolyte mixture was heated at constant temperature (40 ,50 and ,60 °c). the power supply was switch on to start oxidation reaction and the power supply was switch off at different time. figure 2(a) electrochemical desulfurization experimental apparatus, and (b) electrochemical desulfurization experimental sketch (1-power supply, 2-anode, 3-electochemical cell, 4-thermostatic sensor, 5cathode, 6-water bath). table 1 showed selected factors for experimental fuel model. the fuel model and electrolyte are layered. second step is solvent extraction for removing oxidation products by adding 2.5 ml of acetonitrile to 5 ml of desulfurized fuel model. table 1. values of variables used for desulfurization experiments run factors temperature (0 c) time (min) 1 40 10 2 40 40 3 40 50 4 50 30 5 50 40 6 50 50 7 60 10 8 60 20 9 60 30 10 60 40 the final sulfur concentration was measured after electrochemicalextraction desulfurization by using sulfur meter model rx620sa/tanka scintific. 3. result and discussion table 2. results for desulfurization experiments run time temperature final sulfur content (ppm) 1 10 40 1977 2 40 40 1202 3 50 40 1074 4 30 50 1552 5 40 50 1051 6 50 50 980 7 10 60 1875 8 20 60 1550 9 30 60 1344 10 40 60 1275 israa mohammed , hameed hussein alwan , ghanim a. n. /al-qadisiyah journal for engineering sciences 14 (2021) 001–005 3 3.1. impact time on sulfur content as seen in table 2, which listed the desulfurization experiments at different time and temperature with kept nacl concentration constant, the impact of time on sulfur removing was shown in fig. 3, the final sulfur concentration was decreased with time increasing and this is agreeing with many literatures [3, 4, 9] . increasing time meaning increasing contact time between reactants. as seen in fig. 3, the final sulfur concentration is decreasing with temperature but with increasing time the it was started to increasing such as shown at 4o °c and this is may be because off heptane vaporization with increasing time and temperature or this is coming by decreasing in electrolyte conductivity due to releasing heat by oxidation reaction which detain desulfurization reaction as well as electrolysis of water may cause oxygen evolution was lead to energy losses tang et al. [9] . figure 3effect of time on sulfur removal at different temperature in fuel model 3.2 oxidation desulfurization reaction kinetics kinetics reaction for ecd studies at different temperatures against time using nacl concentration 0.106 m. the total sulfur content measured with time (10,20,30,40 and ,50) minutes at temperatures (40, 50 and, 60) º c. the reaction is represented as follow: dbt + h2o2 → prodect (1) − d[cs] dt = k [h2o2] m [cs] n (2) where [cs] is dbt concentration, k is reaction rate constant, t is time, n and m are the reaction rate order in respect to dbt and h2o2 concentration respectively. by assume the h2o2 term dependent can be neglected due to excess amount bej et al. [12] . many workers have been stated that oxidation reaction follows pseudo 1st order reaction, thus equation (2) can be written for n = 1 as: − d[cs] dt = k[cs] (3) where 𝑘 is apparent rate constant, equation (3) can be integrated between two limits: t = 0 → cs = c0, t = t → cs = cf ln ( 𝐶0 𝐶𝑓 ) = −𝑘𝑡 (4) where k is the reaction rate constant [min -1] and cs, cf, and co are concentration of sulfur, final concentration of sulfur and initial concentration of sulfur respectively [mol/l]. when plotting − ln ( 𝐶0 𝐶𝑓 ) with time at different temperatures gives linear equation with high r2 which approves the above assumption of kinetics , the reaction rate constant can be calculated from the slopes of straight lines as showed in fig. 4. the reaction constant and r2 increases with increasing the temperature of the ecd reaction because it strongly temperature dependent [13] , as seen in table 3. figure 4the relation between of ln (c0/cf) and time at studied temperature. table 3. reaction rate constant is calculate based on power law model at different temperature. temp. ( ⃘c) k (min -1 ) r2 40 0.0175 0.9771 50 0.0191 0.8308 60 0.0193 0.6779 according to arrhenius equation estimated the activation energies (ea) for ecd reaction 𝑘 = 𝑘0 𝑒𝑥𝑝 (−𝐸𝑎 / 𝑅 𝑇 ) from slop of draw (ln k) against (1/t) from fig. 5 was calculated the activation energy ea is equal 4.433 kj / mole. in addition to the above kinetics analysis, here levenberg –marquardt algorithm was used to estimate kinetics parameters for more accurate calculation, the levenberg – marquardt algorithm is a statistical technique which combination between gauss –newton and gradient descent methods to solve nonlinear regression by fitting actual experimental results urych et al. [14] . the kinetics factors were estimated by minimize error between actual results and predicated results with using levenberg-marquardt algorithm trejo et al. [15] assume that eco reaction is nth order and interference hydrogen peroxide concentration effect on reaction; so the equation of reaction rate can be represented as followed: 𝑑𝐶 𝑑𝑡 = −𝑘[𝐶𝐷𝐵𝑇] 𝑛 [𝐶𝑃 ] 𝑚 (5) 0 0.2 0.4 0.6 0.8 1 0 20 40 60 ln ( c ∘/ c f) time(min) temp=40 temp=50 temp=60 4 israa mohammed , hameed hussein alwan , ghanim a. n. /al-qadisiyah journal for engineering sciences 14 (2021) 001–005 where [cdbt] and [cp] are dbt and hydrogen peroxide concentration respectively, while n, and m are the reaction order with respect to dbt and hydrogen peroxide respectively. the equation can be integrated to get the following: [𝐶𝐷𝐵𝑇]𝑓 1−𝑛 − [𝐶𝐷𝐵𝑇]0 1−𝑛 = (𝑛 − 1)𝑘[𝐶𝑝 ] 𝑚 𝑡 (6) where [cdbt]f, and [cdbt] 0 are dbt concentration in product and feed respectively. substitute reaction rate constant (k) by using arrhenius formula which lead to the following: [𝐶𝐷𝐵𝑇]𝑓 1−𝑛 − [𝐶𝐷𝐵𝑇]0 1−𝑛 = (𝑛 − 1)𝑘0 𝑒𝑥𝑝 (− 𝐸 𝑅𝑇 ) [𝐶𝑝] 𝑚 𝑡 (7) where: k0 is per exponential for equation of arrhenius, e activation energy in (j/mol) r is universal gas constant (8.314 j/mol k) t is reaction temperature in (k). t is reaction time. equation (7) became: [𝐶𝐷𝐵𝑇 ]𝑓 = [(𝑛 − 1)𝑘𝑜 [𝐶𝑝] 𝑚 𝑡 exp (− 𝐸 𝑅𝑇 ) + [𝐶𝐷𝐵𝑇 ]0 1−𝑛 ] ( 1 1−𝑛 ) (8) the actual experimental result for dbt oxidation reaction were fitted with the equation and analyzed as nonlinear regression by aim of statistaica software version 5, as seen the equation, it has four parameters (n, m, k0 and e). the kinetics parameters values were obtained from nonlinear regression by spss software were: n = 0.78, m= -4.59, k0=582.6 and ea =7.448 for comparison with some previous different oxidation reactions processes for dbt by chemical catalytic reaction and electrochemical reaction were listed in table 4. figure 5effect of temperature on reaction rate constant table 4. activation energy for dibenzothiophene for various oxidation reaction kind of reaction catalyst activation energy kj /mol reference chemical h3p w12 o40 45.9 [16] chemical h3p mo12 o40 29.0 [16] chemical h3 si w12 o40 28.3 [16] chemical hpw/aevm 30.3 [17] chemical fe2o3/graphene 36.26 [3] electrochemical 6.9783 ( emulsion electrolyte) [18] electrochemical 9.1826 ( nonemulsion electrolyte) [18] electrochemical 4.433 * this work electrochemical 7.448 ** this work (*) calculated by power law and, (**) calculated by levenberg-marquardt algorithm. 4. conclusion this study showed that the electrochemical oxidation desulfurization of the model fuel the concentration of dbt was decreased with increased time at a constant amount of nacl and the same temperature. the ecd reaction kinetics show that is obeyed the first-order reaction for desulfurization of dbt by oxidation with h2o2 and reaction rate values 0.0175, 0.0191, and 0.093 at 40, 50, and 60 °c respectively. the ecd reaction show activation energy equal to 4.433 kj/mol. levenbergmarquardt algorithm using is present good agreement for the experimental results in with reaction is obeys (0.78) order and activation energy is 7.448 kj / moles. acknowledgements the authors would like to acknowledge to dr. falah k. matloub the chairman of chemical engineering department at university of babylon, mr. riyadh noaman manager of chemical and petrochemical. references 1. tang, x.-d., et al., deep desulfurization of condensate gasoline by electrochemical oxidation and solvent extraction. 2015. 5(66): p. 53455-53461. 2. ho, t.c.j.c.r.s. and engineering, hydrodenitrogenation catalysis. 1988. 30(1): p. 117-160. 3. alwan, h.h., et al., optimization of oxidative desulfurization reaction with fe2o3 catalyst supported on graphene using box-behnken experimental method. 2020. 15(1): p. 175-185. 4. mehri, f. and s.j.a.i.e.t. rowshanzamir, electrochemical hydrogenation and desulfurization of thiophenic compounds over mos2 electrocatalyst using different membrane-electrode assembly. 2019. 5(1): p. 23-33. 5. ding, y., et al., catalytic oxidative desulfurization with a hexatungstate/aqueous h 2 o 2/ionic liquid emulsion system. 2011. 13(5): p. 1210-1216. 6. babich, i. and j.j.f. moulijn, science and technology of novel processes for deep desulfurization of oil refinery streams: a review☆. 2003. 82(6): p. 607631. 7. zhang, j., et al., photocatalytic oxidation of dibenzothiophene using tio 2/bamboo charcoal. 2009. 44(12): p. 3112-3117. 8. campos‐martin, j.m., et al., oxidative processes of desulfurization of liquid fuels. 2010. 85(7): p. 879-890. 9. tang, x.-d., et al., desulfurization of kerosene by the electrochemical oxidation and extraction process. 2015. 29(4): p. 2097-2103. 10. li, c., et al., ultra‐deep desulfurization of diesel: oxidation with a recoverable catalyst assembled in emulsion. 2004. 10(9): p. 2277-2280. 11. hu, y.l., et al., an inexpensive and convenient procedure for r² = 0.8467 -4.06 -4.04 -4.02 -4 -3.98 -3.96 -3.94 -3.92 0.0029 0.003 0.0031 0.0032 ln ( k ) 1/t(k ⁻¹) israa mohammed , hameed hussein alwan , ghanim a. n. /al-qadisiyah journal for engineering sciences 14 (2021) 001–005 5 chloromethylation of aromatic hydrocarbons by phase transfer catalysis in aqueous media. 2010. 55(1): p. 97-102. 12. bej, s.k., et al., studies on the performance of a microscale trickle bed reactor using different sizes of diluent. 2000. 14(3): p. 701-705. 13. fogler, h.s., elements of chemical reaction engineering. 2020. 14. urych, b.j.j.o.s.m., determination of kinetic parameters of coal pyrolysis to simulate the process of underground coal gasification (ucg). 2014. 13(1): p. 3-9. 15. trejo, f., et al., comparison of different power-law kinetic models for hydrocracking of asphaltenes. 2007. 25(1-2): p. 263-275. 16. choi, a.e.s., et al., mixing-assisted oxidative desulfurization of model sulfur compounds using polyoxometalate/h2o2 catalytic system. 2016. 26(4): p. 184190. 17. huang, p., et al., preparation, characterization and catalytic performance of hpw/aevm catalyst on oxidative desulfurization. 2017. 7(8): p. 4681-4687. 18. li, j.-j., et al., kinetics of desulfurization by electrochemical oxidation in an emulsifying electrolyte. 2017. 35(12): p. 1240-1246. article al-qadisiyah journal for engineering sciences 12 (2019) 172–177 available online at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7703277650. e-mail address: ahmsag@gmail.com. (ahmed sagban saadoon) https://doi.org/10.30772/qjes.v12i3.614 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. effect of cfrp strips orientation on performance of strengthened deep beams ahmed sagban saadoon a* a department of civil engineering, college of engineering, university of basrah, basrah, iraq. a r t i c l e i n f o article history: received 24 august 2019 received in revised form 22 september 2019 accepted 24 september 2019 keywords: deep beams strengthened beams frp strips shear span a b s t r a c t this study was carried out in order to explore the behaviour of rc deep beams strengthening with cfrp strips. eight simply supported deep beams were fabricated and tested under four-points loading scenario. three different orientations for cfrp strips were used for strengthening the rc deep beams ; vertical, horizontal and inclined. all of the tested samples were of the same dimensions, concrete strength and steel reinforcement. a percentage increase in load carrying capacity of 48, 19 and 38% (with respect to the unstrengthened beam) was gained for beams strengthened with vertical, horizontal and inclined frp strips, respectively. it was concluded that the strengthening with frp strips of vertical fabric orientation is more efficient than strengthening with horizontal or inclined orientation since the vertical orientation gives the highest load carrying capacity, largest deflections at ultimate load and smallest crack width. on the other hand, applied the frp strips in a horizontal orientation was insufficient for the strengthening purposes. © 2019 hosting by university of al-qadisiyah. all rights reserved. 1. introduction beams are classified into two classes: deep and shallow. this classified based upon the span/depth or shear span/depth ratio. according to the aci code [1], deep beams are "members in which compression struts are developed between the loads and the supports, and has either clear span/overall depth ≤ 4 or applied concentrated loads within twice the member depth from the face of support". these beams have been used in different engineering constructions. the behaviour of these beams differs from that of shallow behaviour class. in the case of shallow beams, linear strain distribution is developed, and the applied loads usually transfer through diagonal compression regions. the beam strength in such case is generally governed by flexure, and shear is supported by the uncracked concrete region, aggregate interlock, truss action of stirrups and dowel action of main bars. whereas in deep beams, nonlinear strain distribution is developed, and the applied loads transfer similar to the strut and tie action, so the beam strength is generally governed by shear, and the hypotheses theory for shear does not work due to shear deformation and stress redistribution in cracked regions [2]. in severe environments, the classical steel reinforcement does not perform very well for the long term since its performance will change considerably due to the corrosion of steel which causes deterioration or cracking of the concrete structures. many studies have been conducted to find the optimal solution to this problem. different techniques have been proposed, such as galvanization, epoxy coating, cathodic protection and using stainless steel reinforcement, concrete additives, and fiber reinforced polymer (frp) strengthening. only the frp strengthening gives a long term solution [3] due to superior properties of frp composites such as corrosion resistant, higher stiffness and strength, lightweight, and easy handling and application. however, the cost and brittle behaviour of frp composites are the main reasons behind the limited use of frp composites [3]. different studies have been dealt with the using of frp composites as reinforcing, strengthening, wrapping, retrofitting and http://qu.edu.iq/ https://doi.org/10.30772/qjes.v00i0 file:///d:/00%20mechanical%20department/00%20مجلة%20القادسية/استمارات%20ونماذج/qjes/qijes%20ok%202.docx ahmed sagban saadoon /al-qadisiyah journal for engineering sciences 12 (2019) 172–177 173 repairing materials in deep beams. islam et al. [4] studied the performance of six deficient deep beams strengthened externally by bonded frp system. they pointed out that the frp system causes a slower propagation of the diagonal cracks and increases the load carrying capacity of the beam . alshraify [5] studied the performance of deep beams repaired and strengthened by frp strips in shear situation. the results obtained showed that the percentages increase were (58 to 60%) and (47 to 96%) for the repaired and strengthened beams, respectively, with respect to the control beam. lee [6] carried out an experimental study to explore the attitude of deep beams of t-section and with frp sheets strengthening. it was noted that the fiber direction, strengthening length, and anchorage were the main parameters affecting the shear performance. abbas and abdulah [7] investigated the influence of different frp strengthening cases on the capacity and behaviour of indirectly loaded flanged deep beams strengthened in shear. chavan et al. [8] performed experimental tests on deep beams of an external frp reinforcement to investigate its enhancement on the shear strength. a substantial increase in the strength was concluded and the main factor controlling the failure mode was the shear span/depth ratio. alwash et al. [9] studied the behaviour of square concrete slabs reinforced by various ratios of cfrp reinforcement. it was found that the cfrp reinforced slab exhibited ultimate load capacity of 34.62% higher than steel reinforced slab. makki et al. [10] worked on a nonlinear ansys analysis of rpc deep beams. their results showed that the ansys analysis values were close to experimental values with a maximum difference not greater than 7.5% in the values of ultimate load. the current work aims to explore the effect of frp strips orientation on the load carrying capacity and behaviour of strengthened deep beams. this work consists of testing experimentally eight beams in which the whole distance between the two points load and the support for both sides is strengthened by frp strips. the main variable is the orientation of frp fibers. 2. experimental work 2.1. test specimens the experimental work of this study involves fabricating and testing eight deep beams of simple supports condition. six of these beams were externally strengthened with cfrp strips in shear while the two beams were taken as control samples. the flexural reinforcement and dimensions are similar for all of the tested beams. the dimensions of the beam were 1270mm total long, 400mm deep and 150mm wide . it was reinforced longitudinally by three steel bars (ø16mm) and transversely by vertical closed steel stirrups (ø6mm at 150mm c/c spacing). no horizontal shear reinforcement was added to ensure that a shear failure will appear. a nominal concrete strength, around 60mpa, was adopted for all of the tested beams. the distance between the point load and the support for both sides is strengthened by frp strips. the frp strips were applied to the surface of concrete in three orientations: vertical, horizontal and inclined by 45° with horizontal axis, as shown in fig. 1. for each beam’s type, two identical specimens (denoted 1 and 2) having the same details were cast (in order to adopt the average results of them in discussion). details of all beams are shown in table 1. 2.2. materials the properties of the steel bars, frp strips and epoxy used in this study are listed in table 2. a concrete batch was used to cast every two identical beams. the specimens were cast using normal concrete mixes of proportion 1:1:2 and with water/cement ratio of 0.3. the maximum size of coarse aggregate was 20mm and a plasticizer admixture (20ml per 50kg of cement) was also used. the average compressive strength (from testing three 150×150×150mm cubes at 28-days age) for each mix is shown in table 3. 2.3. testing procedure two concentrated vertical loads, 300mm apart, were subjected to each beam. the sheer span and net span were 385mm and 1070mm, respectively. while the ratio of span/depth ratio was 2.68 (satisfying l/h < 4 as recommended by aci code [1] for the requirements of deep beams). to avoid concrete crushing under the points loads, bearing plates above supports and under loads were used. the vertical load was subjected at 5kn increment per (second)?. at each increment, deflections at mid-span and the width of shear crack were recorded via a dial-gauge and zooming in tool (crackmeter), respectively. fig. 2 depicts the testing setup. (a) beams (dbfv#1) and (dbfv#2) (b) beams (dbfh#1) and (dbfh#2) (c) beams (dbfi#1) and (dbfi#2) (d) cross sectional details of all beams figure 1. details of beams 300mm 385mm 385mm 300mm 385mm 385mm 300mm 385mm 385mm 350mm 400mm 50mm 3ø16 2ø12 ø6@150mm 174 ahmed sagban saadoon /al-qadisiyah journal for engineering sciences 12 (2019) 172–177 table 1 beams details table 2 materials properties * from the tension test of three specimens. ** from the manufacturer. figure 2. testing setup 3. results and discussion table 3 gives an outline of the experimental results. the cracking and ultimate loads with their corresponding deflections are shown in the former table. 3.1. modes of failure all of the tested beams were failed in the same manner by a diagonal shear cracking resulting in rupture of frp strips. fig. 3 depicts strengthened specimens table 3 experimental results (a) beam (dbfv#1) (b) beam (dbfh#1) (c) beam (dbfi#1) figure 3. strengthened beams after failure after failure. in all of the tested beams, cracking was started by flexural cracks closely to midspan. no cracks were recorded up to approximately one fifth of the ultimate load. for the beams (dbc) and (dbfh), the first flexural crack appeared at 24 % of ultimate load, while it cracked at 18 % of the ultimate load for the beams (dbfv) and (dbfi). at approximately half of the ultimate load, an inclined diagonal crack began to appear at the left or right shear span region. as loading increased, additional inclined cracks appeared within the region between supports. finally, failure occurred by concrete rupture or crushing at either the tip or along the diagonal crack. dial gauge 300mm 385mm a=385mm 1070mm 400 mm material type ultimate strength (mpa) modulus of elasticity (gpa) steel bars (ø16mm) mild steel 560* 201* steel bars (ø6mm) mild steel 515* 198* frp strips sikahex230 3500** 230** epoxy resin sikadur330 30** 3.8** beam designation cfrp orientation width (mm) depth (mm) span (mm) (a/d) ratio dbc#1 150 400 1070 1.1 dbc#2 150 400 1070 1.1 dbfv#1 vertical 150 400 1070 1.1 dbfv#2 vertical 150 400 1070 1.1 dbfh#1 horizontal 150 400 1070 1.1 dbfh#2 horizontal 150 400 1070 1.1 dbfi#1 inclined 150 400 1070 1.1 dbfi#2 inclined 150 400 1070 1.1 beam designation concrete compressive strength (mpa) cracking load (kn) deflection at cracking load (mm) ultimate load (kn) deflection at ultimate load (mm) dbc#1 59.8 92 0.51 374 3.68 dbc#2 59.8 94 0.49 382 3.72 dbfv#1 61.2 101 0.58 557 5.03 dbfv#2 61.2 99 0.57 561 5.05 dbfh#1 60.8 108 0.54 452 3.93 dbfh#2 60.8 107 0.54 450 4.07 dbfi#1 59.3 97 0.53 524 4.96 dbfi#2 59.3 93 0.55 518 4.87 ahmed sagban saadoon /al-qadisiyah journal for engineering sciences 12 (2019) 172–177 175 3.2. load carrying capacity fig. 4 shows the ultimate load of all of the tested beams, while the percentage increase in the ultimate load of strengthened beams, with respect to the unstrengthened beam (average of each two identical beams), is shown in fig. 5. specimen figure 4. the ultimate load of all tested beams specimen figure 5. percentage increase in ultimate loads the two beams (dbc) were considered as control beams with no any frp strengthening. they were failed at an average load of 378 kn. beams (dbfv) were strengthened by frp strips with a vertical orientation. their failure was due to a diagonal crack at an average load of 559 kn resulting in an increase in load carrying capacity of 48% compared with that of the beams (dbc). while the beams (dbfh), strengthened by frp strips with a horizontal orientation, were failed by a diagonal crack at an average load of 451 kn giving an increase in the beam capacity of 19% compared with that of the beams (dbc). beams (dbfi) were strengthened by frp strips with an inclined orientation and their failure was due to a diagonal crack at an average load of 521 kn resulting in an increase in load carrying capacity of 38% compared with that of the beams (dbc). it is obvious that the beams (dbfv), which strengthened with frp strips of inclined orientation, showed the greatest ultimate load. thus the vertical orientation pattern of strengthening gives the highest capacity as compared with those of inclined and horizontal orientation patterns. on the other hand, the horizontal orientation pattern of strengthening gives the lowest load carrying capacity. 3.3. load-deflection behavior fig. 6 exhibits the load-deflection relationships of all the tested beams. for comparison task, the load-deflection relationships of the beams dbc#1, dbfv#1, dbfh#1 and dbfi#1 are gathered in fig. 7. (a) beams (dbc#1) and (dbc#2) (b) beams (dbfv#1) and (dbfv#2) (c) beams (dbfh#1) and (dbfh#2) (d) beams (dbfi#1) and (dbfi#2) figure 6. load-deflection relationship of tested beams 0 100 200 300 400 500 600 0 1 2 3 4 5 6 l o a d ( k n ) deflection (mm) dbc#1 dbc#2 0 100 200 300 400 500 600 0 1 2 3 4 5 6 l o a d ( k n ) deflection (mm) dbfv#1 dbfv#2 0 100 200 300 400 500 600 0 1 2 3 4 5 6 l o a d ( k n ) deflection (mm) dbfh#1 dbfh#2 0 100 200 300 400 500 600 0 1 2 3 4 5 6 l o a d ( k n ) deflection (mm) dbfi#1 dbfi#2 2nd stage 3rd stage 1 st s ta g e 1 st s ta g e 1 st s ta g e 1 st s ta g e 2nd stage 2nd stage 2nd stage 3rd stage 3rd stage 3rd stage cracking load cracking load cracking load cracking load 176 ahmed sagban saadoon /al-qadisiyah journal for engineering sciences 12 (2019) 172–177 figure 7. load-deflection relationship of beams dbc#1, dbfv#1, dbfh#1 and dbfi#1 from the above curves, it can be demonstrated that the load-midspan deflection response can be divided into (3) stages. in the first stage, a linear relationship was noted in which the load and deflection are proportional. this stage continues to the cracking load. the first deviation to this linear relationship corresponds to this cracking load and the end of this stage represents the proportional limit. within this stage, the materials, concrete and reinforcement, behave as elastic materials and the small cracks developed in the tension section of the beams are still stable. beyond this, the propagation of cracks continues with an increase in their width as loading increases. in the second stage, a nonlinear relationship is observed. this stage begins from the proportional limit and ends near the ultimate load. at the third stage, where the subjected load closes to its ultimate value, the deflection increases at a greater rate compared with the rate of the applied load. as can be seen from fig. 7, decreasing in the slope of the second stage for unstrengthened control beams is greater than that of strengthening beams. due to the presence of frp strips, strengthened beams undergo large deflections at the ultimate condition as referenced to the unstrengthened beams. the average increases in deflection at ultimate load were 36, 8 and 33% for vertical, horizontal and inclined strengthening orientation, respectively. thus, strengthening with frp strips of vertical fabric orientation is more efficient than strengthening with horizontal or inclined orientation since the vertical orientation gives the highest ultimate load and largest deflections at ultimate load. on the other hand, it has seemed that the horizontal orientation is considered inadequate for the strengthening purposes since it gives ultimate load and corresponding deflection not much greater than those of the unstrengthened control beams. 3.4. shear crack pattern the load causes the appearance of the diagonal crack is called the shear cracking load. this crack suddenly appears at the mid of shear span. as loading increased, the diagonal crack extends towards the loading and support points. its maximum width usually occurred at the beam’s middepth. fig. 8 gives the width of shear crack against the applied load for the beams dbc#1, dbfv#1, dbfh#1 and dbfi#1. the cracks width was recorded up to approximately 95% of the ultimate load since it cannot be recorded at ultimate load. from this figure, the maximum crack widths were 4.1, 1.2, 3.6 and 1.4mm for beams dbc#1, dbfv#1, dbfh#1 and dbfi#1, respectively. it is obvious that the unstrengthened beam exhibits relatively large crack width at failure and the frp strengthening minimizes the width of cracks. for the beam (dbfv#1), the percentage decrease in maximum crack width was about 70% of that for the beam (dbc#1). strengthening with vertical or inclined frp strips is very adequate in minimizing the crack width as compared with horizontal frp strips. figure 8. load-crack width relationship 4. conclusions the following points can be presented as a conclusion for this study:  all of the strengthened beams were failed in the same manner by a diagonal shear crack resulting in rupture of frp strips.  a gaining in load carrying capacity of 48, 19 and 38% (compared with the unstrengthened beam) was observed for beams strengthened with vertical, horizontal and inclined frp strips, respectively.  for strengthened beams, the load-midspan deflection response was much stiff than that of the unstrengthened beams.  strengthening with frp strips minimizes the width of cracks. for the vertical strengthening, the percentage decrease in the maximum crack width was about 70% of the maximum crack width of the unstrengthened beam.  strengthening with frp strips of vertical fabric orientation is more efficient than strengthening with horizontal or inclined orientation since the vertical orientation gives the highest load carrying capacity, largest deflections at ultimate load and smallest crack width.  it seemed that the horizontal orientation was inadequate for the strengthening purposes since it gives ultimate load and corresponding deflection not much greater than those of the unstrengthened control beams. references [1] aci committee 440, 2014, “guide for the design and construction of externally bonded frp systems for strengthening of concrete structures,” american concrete institute, michigan, usa. [2] k.h. yang, a.f. ashour, and j.k. song, 2007, “shear capacity of reinforced concrete beams using neural network,” international journal of concrete structures and materials, 1(1):63-73. [3] n.f. grace, a.k. soliman, g. abdel-sayed, and k.r. saleh, 1998, “behavior and ductility of simple and continuous frp reinforced beams,” asce journal of composites for construction, 2(4):186 – 194. [4] m.r. islam, m.a. mansur, and m. maalej, 2005, “shear strengthening of rc deep beams using externally bonded frp systems”, cement and 0 100 200 300 400 500 600 0 1 2 3 4 5 6 l o a d ( k n ) deflection (mm) dbc#1 dbfv#1 dbfh#1 dbfi#1 0 100 200 300 400 500 600 0 1 2 3 4 5 l o a d ( k n ) crack width (mm) dbc#1 dbfv#1 dbfh#1 dbfi#1 https://www.sciencedirect.com/science/journal/09589465 ahmed sagban saadoon /al-qadisiyah journal for engineering sciences 12 (2019) 172–177 177 concrete composites, 27(3):413-42. [5] b.i. al-shraify, 2009, “behavior of reinforced concrete deep beams strengthened with carbon fiber reinforced polymer strips”, ph.d thesis, university of baghdad. [6] h.k. lee, s.h. cheong, s.k. ha, and c.g. lee, 2011, “behavior and performance of rc t-section deep beams externally strengthened in shear with cfrp sheets”, composite structures, 93(2):911-922. [7] r.a. abbas and m.d. abdulah, 2013, “behavior of reinforced concrete deep beams strengthened with cfrp sheets”, elixir cement and concrete composites, 62(2013): 17696-17700. [8] p.c. chavan, c.p. pise, y.p. pawar, and s.s. kadam, 2017, “strengthening of reinforced concrete deep beam using frp wrapping”, inter. j. of eng. sci. & research technology, 6(11):347-358. [9] n.a. alwash, bylon, g.m. habeeb, and f.h. al-mamoori, 2017, “flexural behavior of light weight concrete slab panels reinforced with cfrp bars”, al-qadisiyah journal for engineering sciences, 10(4):368-383. [10] r.f. makki, a.t. jassem, and h. a. jassem, 2018, “non-linear analysis of reactive powder concrete (rpc) deep beams with openings strengthened by cfrp”, al-qadisiyah journal for engineering sciences, 11(2):176-196. https://www.sciencedirect.com/science/journal/09589465 template for academica science journal al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 80 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. old tahoe and tahoe congestion control algorithms for tcp sabbar insaif jasim lecturer in al-dour institute,salah-adden, dour. sabbarjan@yahoo.com received on 18 january 2017 accepted on 8 april 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.522 abstract :one of the imperative elements of tcp is the congestion control of the system which happen when numerous info streams touch base at a router whose yield limit is not as much as the whole of the data sources. this paper introduced how old tahoe (congestion avoidance) could and tahoe (fast retransmit) affect the congestion control. the system was simulated using network simulation program (netsim) to study the performance of system in terms of delay and utilization for old tahoe (congestion avoidance) and tahoe when the congestion occurred and when there is no congestion and no error and the results showed that fast retransmit was better utilization and low delay than congestion avoidance. keywords: ”transmission control protocol", "protocol data unit", "user datagram protocol", "customer-provided equipment", "ack" الخالصة بروتوكول التحكم باالرسالللـ الوظائف المهمة ان احدى tcp او ما يسمى في الشبكة التحكم في الزخم المروري للمعلومات هو مجموع أقل من خرجه تكون سعة الذي جهاز التوجيه )الراوتر( يصل العديد من معلومات إلىيحدث عندما الذياالزدحام قنية تاهو الذي هو خليط من البدء البطيء وتجنب االزدحام(، وت) تاهو القديم لتقنية كيف يمكن هذا البحث يقدم عمليا. مدخالته ) باستخدام برنامج محاكاة وقد تم محاكاة النظام. التحكم في االزدحام ان تؤثرعلى سريعة(،االرسال البإعادة ) netsim ) لدراسة ج كفاءة النظام من حيث التاخير الزمني ولتاهو القديم وتاهو عندما يحث االزدحام وعند عدم وجود اي ازدحام او خطأ، والنتائ اظهرت ان تقنية اعادة النقل السريع هي افضل من تقنية تجنب االزدحام. introduction most present internet applications rely on the (tcp) to convey information dependably over the system. (tcp) conveys most of the internet activities, so internet execution depends, all things considered, on how well tcp functions. execution characteristics of a particular type of tcp are described by the blockage control figuring [2]. blockage can happen when information touches base from a quick system to a slower arrange. congestion can likewise happen when various information streams touch base at a switch whose mailto:sabbarjan@yahoo.com al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 81 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. yield limit is not exactly the entirety of the inputs. tcp is predomfinantly used to dodge congestion in the system. this paper presents how the tahoe and old tahoe would vary the blockage control of tcp. 1. services and principles of transport layer living between the application and framework layers, the transport layer field is in the focal point of the layered framework plan. it has the fundamental piece of giving correspondence benefits particularly to the application frames running on different hosts. a transport layer field convention accommodates intelligent correspondence between application forms running on various hosts. by "predictable" correspondence, this infers notwithstanding the way that the passing on application techniques are not physically connected with each other (in reality, they might be on various sides of the planet, associated by means of various switches and an extensive variety of connection sorts), from the applications' point of view, it is as if they were physically related. application shapes use the sensible correspondence gave by the transport layer to send messages to each other, free for the worry of the purposes of enthusiasm of the physical base used to pass on these messages [6]. figure 1: logical communication as showed up in figure (1), transport layer protocol s are executed finally structures yet not in framework switches. framework switches simply follow up on the system layer fields of the layer-3 pdus (protocol data unit); they don't follow up on the transport layer fields [6],[9]. at the sending side, the transport layer changes over the messages it gets from a sending application process into 4-pdus (that is, transport-layer protocol data units). this is done by (maybe) breaking the application messages and adding a transport layer header to each piece to make 4-pdus. the layer at that point passes the 4-pdus to the framework layer, where each 4-pdu is exemplified into a 3-pdu. at the reviwer side, the layer gets the 4-pdus from the system layer, removes the transport header from the 4pdus, reassembles the messages and passes them to an accepting application process. a pc system can make more than one layer protocol available to arrange applications. for example, the internet has two protocols tcp and udp(user datagram protocol). each of these protocols gives a substitute course of action of layer organizations to the conjuring application. all layer protocols give an application multiplexing/demultiplexing organization. this organization will be depicted in purpose of interest in the following area. a transport convention can give different administrations logical end-end transport router r1 router r2 router r3 host h2 applicatio n transport network data link physical applicatio n transport network data link physical network d1 d1 d1 ph ph ph network d1 d1 d1 ph ph ph network d1 d1 d1 ph ph ph network d1 d1 d1 ph ph ph actual pdu flow host h1 router r4 al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 82 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. to conjuring applications, including solid information exchange, data transfer capacity ensures, and defer ensures [6],[9]. 2. review of the transport layer in the internet the internet and all things considered a tcp/ip system, makes accessible two particular transport-layer conventions to the application layer. one of these protocols is udp (user datagram protocol), which gives a dishonest, connectionless help of the conjuring application. the second of these protocols is tcp , which gives a untrustworthy, connectionless support of the conjuring application. exactly when arranging a framework application, the application build must decide one of these two transport protocols [6].the application designer chooses amongst udp and tcp while making attachments. the most important commitment of udp and tcp is to build up ip's transport organization between two end systems to a movement organization between two methods running on the end structures. extension out host-to-host moves to procedure transmission is called application multiplexing and demultiplexing. udp and tcp likewise give uprightness checking by incorporating mistake identification header's fields. these two negligible transport-layer organizations, host-to-host data movement and blunder checking are the fundamental two organizations that udp gives. specifically, similar to ip, udp is a problematic administration it doesn't promise information sent by one procedure will touch base in kindness to the destination procedure. a convention that gives solid information exchange and blockage control is essentially intricate [11], [12]. 3. connection-oriented transport: tcp tcp is a reliable data trade protocol that is realized over a pass (ip) end to end framework layer. all the more generally, the layer underneath two constantly passing on endpoints may involve a singular physical association (e.g., as on account of a connection level information exchange convention) or a worldwide internetwork (e.g., as on account of a transport level convention). for our motivations, be that as it may, this lower layer basically as a flawed point-to-point channel can be seen. tcp depends on a large portion of the fundamental standards including mistake location, retransmissions, aggregate affirmations, and clocks for arrangement and affirmation numbers. the key part of tcp is its ability to give a strong, bi-directional, virtual channel between any two hosts on the internet. since the protocol works over the ip framework, which gives simply best-effort administration to conveying parcels over the system, the tcp standard indicates a sliding window based stream control. [2]. 3.1. tcp connection tcp gives multiplexing, demultiplexing, and blunder location (however not recuperation) in the very same way as udp. by and by, tcp and udp contrast from numerous points of view. the most essential distinction is that udp is not connected, while tcp is association situated. the connectionless of udp is in light of the fact that it sends information while never building up an association. tcp is affiliation organized in light of the way that before one application method can begin to send data to another, the two procedures should first "handshake" with each other, that is, they ought to send some preliminary parts to each other to set up the parameters of the accompanying data trade. as an element of the tcp affiliation establishment, the two sides of the affiliation will present various tcp "state factors" [7],[8]. 3.2. tcp congestion control. a tcp association controls its transmission rate by restricting its number of transmitted yet-to-berecognized portions [5]. blockage can happen when data connects on a noteworthy pipe such as a quick lan and gets passed on through a humbler channel which seen in a slower wan for example. congestion can likewise happen when diverse data meet up at a switch whose yield constrain isn't precisely the total of the sources of info [6],[9]. al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 83 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3.3. control algorithms in tcp congestion there are four standard blockage control calculations that are presently in like manner use. each of the counts noted here was extremely laid out much sooner than the standard was circulated. their accommodation has easily finished the trial of time. the four counts, slow start, congestion avoidance, fast re transmit and fast recovery are depicted underneath [1], [12]. figure (2) underneath portrays what an average tcp information exchange stage utilizing tcp blockage figure 2: congestion control overview control may resemble. notice the seasons of exponential window estimate increase, coordinate augmentation and drop-off, each of these circumstances depicts the sender's response to comprehended or express banners it gets about framework conditions [11], [12]. 4. old tahoe and tahoe 4.1. old tahoe: tcp tahoe is the easiest one out of the four variations. it doesn't have fast recovery.. at congestion avoidance phase, it treats the triple copy acks same as timeout. whenever timeout or triple copy acks is gotten, it will perform quick retransmit, decrease blockage window to 1, and enters moderate begin phase.[3],[4]. the supposition of the calculation is that the bundle misfortune brought on by harmed is little may be less than 1%, as needs be the death of a bundle signals obstruct some place in the framework between the source and goal. there are two indications of bundles setback: a timeout phenomenon and the receipt of duplicate acks. stop shirking and moderate begin requires two factors to be kept up for every association: a congestion window (cwnd) and a slow start threshold size(ssthresh). old tahoe calculation is the mix of moderate begins and blockage evasion. the consolidated calculation works as takes after: presentation for a given affiliation sets cwnd to one part and ssthresh to 65535 bytes. at the point when congestion happens (appeared by a timeout or the social occasion of duplicate acks), one-bit of the present window appraise (the base of cwnd and the beneficiary's advanced window, however no under two areas) is saved in ssthresh. moreover, if the blockage is appeared by a timeout, cwnd is set to one bit, means slow rate.[10]. 4.2. tahoe (quick (fast) retransmit): tahoe variety is the operation that called on the fast retransmits calculations working with old tahoe. tcp may create a fast certification (a copy ack) when an out-of-ask for segment is escaped ask for, and to tell it what grouping number is normal. al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 84 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. since tcp does not know whether a copy ack is realized by a lost bit or just a re-asking for of areas, it sits tight for somewhat number of copy acks to be gotten. it is acknowledged that if there is just a reordering of the parts, there will be one and just or two copy acks before the re-asked for partition is readied, which will then make another ack. in the event that three or more duplicate acks are received in a row, it is a strong sign that a bit has been lost. tcp at that point plays out a retransmission of what radiates an impression of being the missing area, without sitting tight for a re-transmission clock to end [8],[10]. 5. procedure: the network was simulated using network simulation to study the congestion control algorithms of tcp. 5.1 sample 1 (old tahoe): 1in this sample figure 3, 2 cpe's and 2 routers are used figure 3: sample 1 connection 2-devices which are inter connected, with router1 is cpe1 by link 1,while cpe2 is connected with router2 by link 3 in which cpe2 is off transmission in this case 3-link 2 is connected with router 1 and router 2. where cpe is customer-provided equipment, the simulation time was taken for 60 seconds to show the results in figure 4, table 1 represents the utilization for sample (1) and table 2 represents the delay for sample (1) figure 4: delay al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 85 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table (1) utilization for sample (1) 1 utilization 70.611 % 1.1 effective utilization 67.470 % 1.2 overhead 2.284 % 1.3 loss 0.857 % 2 unutilized 29.389 % table (2) delay for sample (1) 1 delay 2.900 (ms) 100 % 1.1 queuing delay 1.504 (ms) 51.8664 % 1.2 propagation delay 0.005 (ms) 0.1724 % 1.3 transmission delay 1.391 (ms) 47.9612 % 5.2 sample 2 (tahoe): as shown in figure 5, 1two cpe & two routers are used. 2these inter connected devices are connected in the following manners: arouter1 in link1 connected with cpe1 brouter2 by link 3 connected with cpe2 which is note in transmission data case clink 2 connected with router1 and router2. figure 5: sample 2 connection the simulation time was taken for 60 seconds to show the result figure 6 ,table 3 represents the utilization for sample (2) and table 4 represents the delay for sample (2). al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 86 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 6: sample 2 delay table (3) utilization for sample (2) 1 utilization 83.773% 1.1 effective utilization 80.024 % 1.2 overhead 2.709 % 1.3 loss 1.040 % 2 unutilized 16.227 % table (4) dely for sample (2) 1 delay 3.312 (ms) 100% 1.1 queuing delay 1.916 (ms) 57.8420 % 1.2 propagation delay 0.005 (ms) 0.1510 % 1.3 transmission delay 1.391 (ms) 42.0070 % 5.3 sample 3 (old tahoe with no congestion and no error): this sample shown in figure 7 with the following notations: 14 cpe & 2 routers are used. 2the devices are inter connected in the following arrangement: a) cpe 1 and 2 are connected with router 1 by link 1 and 2 respectively. b) cpe 3 and 4 are connected with router 2 by link 3 and 4 respectively. c) cpe 3 and cpe 4 are not transmitting data in this case. d) router 1 and router 2 are connected by link 5. al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 87 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7: sample 3 connection the simulation time was taken for 60 seconds to show the results figure 8, table 5 represents the utilization for sample (3) and table 6 represents the delay for sample (3) figur_ (8) sample 3 delay table (5) utilization for sample (3) 1 utilization 64.322 % 1.1 effective utilization 62.517 % 1.2 overhead 1.805 % 1.3 loss 0000 % 2 unutilized 35.678 % table (6) delay for sample (3) 1 delay 499.913 (ms) 100 % 1.1 queuing delay 371.059 (ms) 74.2247 % 1.2 propagation delay 0.005 (ms) 0.0010 % 1.3 transmission delay 128.849 (ms) 25.7743 % al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 88 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 5.4 sample 4 (tahoe with no congestion and no error): the operation in this sample is seen as in figure 9, in which 4 cpe and 2 routers are used. the inter connection of sample is done as follow: 1. cpe 1 and 2 with router 1 by link 1 and 2 respectively. 2. cpe 3 and with router 2 by link 3 and 4 respectively. 3. cpe 3 and cpe 4 are are in case of no transmissions.. 4. by link 5 router 1 and router 2 are connected. figure 9: sample 4 connection so: 1. the simulation time was taken for 60 seconds to show the results figure 10, table 7 represents the utilization for sample (4) and table 8 represents the delay for sample (4). 2. the utilization metric was taken for all samples for comparison as shown in figure 11: 3. the delay metric was taken for all samples for comparison as shown in figure 12: 4. the delay for sample 1 and sample 2 was shown in figure (13) 5. the delay for sample 3 and sample 4 is the same as shown in figure (14) figure 10: sample 4 delay al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 89 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 11: utilization for all samples figure 12: delay for all samples figure 13:sample 1 & sample 2 delays al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 90 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 14: sample 3 dely is typical on sample 4 delay discussion and conclusions: 1tcp is mainly used for the purpose to avoid congestion in the network. 2when we run the above scenario without tcp, congestion happens in light of the fact that various information streams land at a router whose yield limit (10 mbps) is not as much as the aggregate of the data sources (16.88mbps). it increases the number of dropped packets and decreases utilization. 3when run in a same scenario by using tcp, it helps in avoiding the congestion in the network by using the old tahoe congestion control algorithm. it results increase utilization. 4from sample 1 and sample 2, old tahoe and tahoe congestion control algorithms affect the utilization of the network, differently. old tahoe holds up until the point that the timer terminates before retransmitting a lost bundle. yet, tahoe retransmits the lost parcel instantly subsequent to getting three continuous copy ack's. these outcomes in the expanded bundle transmission and along these lines organize usage and delay were higher on account of tahoe. 5from sample 1 and sample 2, the delay due to old tahoe congestion control algorithm is larger than delay due to tahoe congestion control algorithm. 6from sample 3 and sample 4, utilization and delay for old tahoe & tahoe is same because there were no possibility for congestion to happen, cpe 1 & cpe 2 is sending the packets at data rate 64 kbps & r1 is sending the packets at data rate 10mbps.so, there is no possibility for packets dropped, therefore, if there is no congestion, both algorithm works same. 7there were large difference between the delay when no congestion in the network and when the congestion occurs. 8tahoe (fast retransmit) is the best due to better utilization since tcp plays out a retransmission of what has all the earmarks of being the missing portion, without sitting tight for a re-transmission clock to terminate. references: 1. alaa s.g,; yacine g.d.; sidi m. s., "a performance study of tcp variants in terms of energy consumption and average goodput within a static ad hoc environment", iwcmc'2006, vancouver, canada, juillet 2006. 2. alexander a.; neil t., peter r.; and leonard k., " host-to-host congestion control for tcp ", ieee communications surveys & tutorials, vol. 12, no. 3, pp. 304-342, 2010. 3. allman, m.; paxson; v.; and blanton, "tcp congestion control", rfc 5681. e. 2009. al-qadisiyah journal for engineering sciences vol. 11 no. 1 issn: 1998-4456 page 91 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4. fall, k.; and floyd, s. "simulation-based comparisons of tahoe, reno and sack tcp. acm sigcomm computer communication review", 26(3):5-21. 1996. 5. hakim weatherspoon, "high performance systems and networking", cornell university, september 5, 2014 6. james f. k.; and keith w. r., " computer networking a top-down approach featuring the internet ", addison wisley, 2000. 7. jim k.; keith r., "computer networking", a top down approach 6th edition addison-wesley march 2012 8. kevin f.; and sally f., "simulation-based comparisons of tahoe, reno, and sack tcp", lawrence berkeley national laboratory one, v0.ps.z (december 1995) . 9. netsim program ver.10 10. roman, "tcp tahoe, reno, new reno, and sack–a brief comparison", a journey to software craftsmanship, november 10, 2011 11. van jacobson. "congestion avoidance and control. computer communications review", volume 18 number 4, pp. 314-329,1988. 12. van jacobson, "modified tcp congestion control avoidance algorithm", end to end-interest mailing list, 1990. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 106 mathematical extraction equation of horizontal shear transfer in interface between two concrete members dr. hakim s. m. al-kurayshi civil technical department, najaf technical institute al-furat al-awsat technical university, iraq assistant professor , email: ntit.10006@gmail.com received 14 september 2015 accepted 23 november 2015 abstract shear is transferred through interface between two concrete members by two mechanisms either by aggregate interlock or by dowel action or by both in the same time. this media is very complex and there are so many variables affecting shear transfer like surface shape and final treatment of the concrete surfaces. histories of the previous researchers are mentioned in this paper to find out the applicable results of their equations. it is noticed that most of them depend on only clamping stress due to dowel action while others used besides that the type of concrete used namely its compressive strength. a mathematical statistical trials are made in this paper to find out the most accurate and suitable equation which simulates the action happened in this media. an equation of six parameter polynomial is obtained containing clamping stress and compressive strength of concrete. assumed values of the mentioned variables are used in this equation to find out the horizontal shear strength. the deviation recorded is about 4% which is an acceptable one. keywords: shear transfer, polynomial, shear stress, slip, and interface. introduction when two concrete members cast in different times, an interface will be formed between the contact surfaces of the two members as they are constructed one over the other. shear is transferred across that interface between the two members which can slip relative to one another. an example of those members is a beam and deck sections and, in order of them to act compositely, horizontal shearing forces must be transferred through interface between them at contact surfaces figure (1). the shear is transferred by two mechanisms namely aggregate interlock and dowel action due to the existence of shear connectors like steel bars or studs of steel sections. the aggregate interlock depends on the concrete of the two surfaces and as a result on the coefficient of friction between the two surfaces. it depends also on the finishing treatment of the concrete surface if it is smooth or rough or in between these two. mailto:ntit.10006@gmail al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 107 in most of the literature researchers, the researchers focus on the dowel action of steel bars pass through the two concrete members. others were studying the effect of aggregate interlock besides dowel action. unfortunately, the results of horizontal shear transfer equations suggested by them were not coincided to some extent. in this paper the work will be classified into two groups depending on the variables taken by them. first group that took the clamping stress as a main effective variable in shear evaluation. the second group which is near the truth was taking the compressive strength of concrete into account besides the clamping stress. . shear transferred through dowel action only (first group work) shear transferred by this mechanism when shear connectors are used like bars or any other steel studs which are inserted in the two concrete members to join one to other. the ratio of steel used is taken to be and the clamping stress of these connectors is where is yield stress of steel used. there had been so many proposed equations to find out the horizontal shear strength through interface in composite sections. these equations can be summarized here according to the people who found it out as shown in table 1. shear transferred through dowel action and concrete strength (second group work) these equations were taking into account the clamping stress and concrete compressive strength. they are as mentioned in table 2. present work in the literature it is seen that people who were working on equations without taking concrete compressive strength reached an incorrect results of horizontal shear strength while those who were taking that into considerations had far results. an equation is derived depending upon the results of the previous work. the equation governed depends on the following procedure: 1. the work of people who were working on shearing strength related to only clamping stress was drawn on one plot as shown on figure (2). the values of clamping stress were taken from 0 to 350 psi by an increment of 50 psi [from 0 to 2.415 mpa by an increment of 0.345 mpa] .the points of the relation between shear strength and clamping stress were represented by the most suitable and compatible curve. that curve was polynomial of six parameters. the equation obtained is very near to the truth and it represents the work of so many researchers. each equation of the literatures work was represented through an average values taken as mentioned in table (3). 2. the horizontal shear strength is also depending not only on clamping stress but on concrete strength also. the two parameters. the work of these peoples are assembled through using their governed equations and an assumed values of concrete compressive strength. the values of the compressive strengths of a normal weight concrete are taken from 10 mpa to 40 mpa by an increment of 5 mpa. figures 3, 4, 5, 6, 7, 8 and 9 are representing the relation between shear strength and clamping stress. these curves are corresponding to 10 mpa concrete compressive strength, 15 mpa, 20 mpa, 25 mpa, 30 mpa, 35 mpa and 40 mpa respectively. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 108 in each of these figures same polynomial of six parameters is used to reach the equations which are representing the most acceptable relation between horizontal shear strength and clamping stress. to reach a unified equation that has clamping stress and compressive strength variables, it is assumed that the final equation can be represented by the following polynomial equation: (1) where here represents the horizontal shear strength (mpa) and x is the clamping stress ( also in mpa. c,s are functions of . each equation governed corresponding to the compressive strength used has six parameters which are functions of . these parameters can be seen in table (4). so if c1 is taken to be drawn against the values of concrete compressive strength then seven values of c1 will be used against seven values of concrete compressive strength. this truth is translated to a plot shown in figure (10) from which a correlated representative curve is obtained. figures 11,12,13,14 and 15 are plots against c2 ,c3 ,c4 ,c5 and c6 respectively. the following equations are taken from the plots: , , , , the final equation is obtained by substituting these parameters in eq.(1) to get: [ ][ ] [ ][ ] [ ][ ] [ ][ ] [ ][ ] [ ] (2) discussion of the results and conclusions the obtained equation seems to be long and complicated due to its inclusion of so many numbers and parenthesis, so its validity must be checked by comparing the outputs with the results of first and second worker groups. to make the comparison logically and reasonable an example of the variables used in this equation must be assumed. the values of these variables are taken to be 20 mpa for compressive strength of concrete and equal to 2 mpa for clamping stress. the horizontal shear strength obtained by eq.( 2) is 3.11 mpa. 1. comparison with first group: the shear strength equation of this group is that which is mentioned in figure (2) as follows: [ ] [ ] + [ ] [ ] [ ] after the substitution of the clamping stress value, the shear strength obtained is 3.9022 mpa. the deviation between the two results is 20%. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 109 2. comparison with second group: the shear strength of the work of this group can be obtained from equation mentioned in figure (5): [ ] [ ] + [ ] [ ] [ ] the result of the shear strength after substitution of the assumed clamping stress and concrete compressive strength is 3.2423 mpa, so the percentage deviation is 4%.fig.(16) shows a comparison between the output of the present equation for so many values of clamping stress and compressive strength of concrete is 20 mpa with what was governed by using equations obtained by walraven , loov and loov&patnaik .it seems to be taking approximately an average style. conclutions from the results of comparison, the following conclusion points can be drawn: a. the values of horizontal shear strength governed by eq.(2) always give lower bound values therefore the use of this equation in design is almost safe because the designer will be forced to increase the clamping stress through increasing number of dowel bars . b. from the results it is seen that the deviation of the first group is very high (20%) compared to (4%) deviation of the second group work. this is noticed because aggregate interlock was not taken to account. it is advisable in design to follow this equation or second group work since they are near the acceptable results. c. an average values are taken for horizontal shear strength in the work of all the researchers to stand on a moderate values and not on upper or lower bound values. for example the results of loov & patnaik were always high and gave upper bound values compared to others like walraven for example. references [1] birkeland , p.w. ,and birkeland, h.w.(1966), “connections in precast concrete construction”, aci [2] building code requirements for structural concrete, aci318-02(2002).american concrete institute, farmington hills, michigan. [3] hsu, t.t.c., mau, s.t., and chen, b. (1987), “theory of shear transfer strength of reinforced concrete”, aci journal, vol.84, no.2, pp.149-160. [4] loov, r.e.(1978),”design of precast connections”, paper presented at a seminar organized by compa international pte , ltd. [5] loov ,r.e. ,patnaik ,a.k.(1994),”horizontal shear strength of composite concrete beams with a rough interface”, pci journal, vol.39, no. 1, pp.48-66. al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 110 [6]] mast, r.f.(1968),”auxiliary reinforcement in concrete connections”, asce journal, vol.94,no.st6.,pp.1485-1504. [7] mattock, a.h.(1974),”shear transfer in concrete having reinforcement at an angle to the shear plane”, shear in reinforced concrete, aci special publication sp-42,vol.1, american concrete institute,detroit, mi,pp.17-42. [8] mattock, a.h. , johal ,l., and chow, h.c.(1975),”shear transfer in reinforced concrete with moment or tension across the shear plane”, pci journal, vol.20, no. 4, pp.76-93. [9] pci design handbook-precast and prestressed concrete (1992), fourth edition, precast/prestressed concrete institute. chicago, il. [10] saemann , j.c. ,and wash ,g.w.(1994) ,” horizontal shear connections between precast beams and cast-in-place slabs” , aci journal,vol.61,no.11, pp.1383-1408. [11] shaikh, a.f. (1978) ,” proposed revisions to shear-friction provisions”, pci journal, vol.23, no.2, pp.12-21. [12] walraven, j. ,frenay , j., and pruijssers ,a.(1987) ,” influence of concrete strength and load history on the shear friction capacity of concrete members “,pci journal, vol.32, no.1, pp.66-84. table (1): shear transferred through dowel action only (fist group work) equation number researchers proposed equation surface treatment and concrete compressive strength 1 saemann and washa (1964) ( ) where = ultimate shear strength in psi. d = effective depth. = percent steel crossing the interface. not taken into consideration 2 birkeland and birkeland (1966) √ not taken into consideration 3 mast (1968) where is the coefficient of friction at the interface. not taken into consideration 4 shaikh (1978) where = 0.85 for shear (psi) 𝛌=1.0 for normal weight concrete. this equation can be simplified into (for normal weight concrete); taken into consideration al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 111 √ 5 aci code 318 / 318 r -2002 …...… (a) ….…….b) ……..... c) √ ( ) (when there is min. shear reinforcement and contact surfaces are roughened to a full amplitude of approximately ¼ in) and if ....….d) taken into consideration vu =factored shear force, ø=0.75, bv=the width of the interface, d=distance from extreme compression fiber to centroid of tension reinforcement for entire composite section. avf =area of reinforcement. fy =yield stress of shear reinforcement. ac= the area of concrete section resisting shear transfer. fc'=concrete strength. µ=1.0 for normal weight concrete placed against hardened concrete with surface intentionally roughened. s= spacing of shear reinforcement. table (2): shear transferred through dowel action and concrete strength (second group work) equation number researchers proposed equation surface treatment and concrete compressive strength 6 walraven et al (1987) [ ] where here is equal to 0.85 times the compressive strength of 150 mm cubes. taken into consideration to some extent 7 mattock (1974) [ ] (psi) taken into consideration to some extent 8 mattock (1975) (psi) taken into consideration to some extent 9 loov (1978) √ is constant and equal to 0.5 for initially uncracked surface. similar equation was taken into consideration to some extent al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 112 proposed by hsu et al (1987) using equal to 0.66 for both cracked and uncracked surfaces. 10 loov and patnaik (1994) √ =0.6 and =1.0 for normal weight concrete. taken into consideration to some extent table (3): horizontal shear strength and clamping stress for different concrete strengths mpa clamping stress mpa mpa 0 0.345 0.690 1.035 1.380 1.725 2.070 2.415 brikeland 0 1.635 2.312 2.831 3.269 3.655 4.004 4.324 0 mattock 2.76 3.040 3.310 3.590 3.860 4.140 4.420 4.690 0 shaikh 0 1.420 2.010 2.460 2.840 3.180 3.480 3.760 0 average 0.92 2.030 2.544 2.960 3.323 3.659 3.968 4.258 0 walraven 0 0.720 0.910 1.040 1.150 1.237 1.316 1.368 10 loov 0 1.220 1.730 2.120 2.450 2.740 3.000 3.240 10 loov &patnaik 0 1.270 1.690 2.020 2.310 2.550 2.800 3.010 10 average 0 1.070 1.440 1.730 1.790 2.180 2.370 2.550 10 walraven 0 0.734 0.955 1.115 1.243 1.353 1.450 1.540 15 loov 0 1.500 2.100 2.600 3.000 3.400 3.700 3.970 15 loov &patnaik 0 1.560 2.070 2.480 2.830 3.140 3.420 3.690 15 average 0 1.260 1.710 2.070 2.360 2.630 2.860 3.070 15 walraven 0 0.732 0.980 1.160 1.310 1.440 1.550 1.660 20 loov 0 1.750 2.490 3.050 3.530 3.940 4.320 4.670 20 loov &patnaik 0 1.830 2.430 2.910 3.320 3.690 4.020 4.330 20 average 0 1.440 1.970 2.370 2.720 3.020 3.300 3.550 20 walraven 0 0.730 0.990 1.180 1.350 1.490 1.620 1.730 25 loov 0 1.940 2.740 3.360 3.880 4.330 4.750 5.130 25 loov &patnaik 0 2.010 2.670 3.200 3.650 4.060 4.420 4.760 25 average 0 1.560 2.130 2.580 2.960 3.290 3.600 3.870 25 walraven 0 0.720 1.000 1.210 1.380 1.530 1.670 1.800 30 loov 0 2.120 3.000 3.680 4.250 4.750 5.200 5.620 30 loov &patnaik 0 2.200 2.930 3.510 4.000 4.440 4.840 5.120 30 average 0 1.680 2.310 2.800 3.210 3.570 3.900 4.180 30 walraven 0 0.711 1.000 1.220 1.410 1.570 1.720 1.850 35 loov 0 2.290 3.240 3.970 4.590 5.130 5.620 6.070 35 loov &patnaik 0 2.380 3.160 3.790 4.320 4.800 5.230 5.630 35 average 0 1.790 2.470 3.000 3.440 3.830 4.190 4.520 35 walraven 0 0.707 1.010 1.240 1.430 1.610 1.760 1.910 40 loov 0 2.450 3.470 4.250 4.900 5.480 6.000 6.490 40 loov &patnaik 0 2,54 3.380 4.050 4.620 5.130 5.590 6.020 40 average 0 1.052 2.620 3.180 3.650 4.073 4.450 4.807 40 al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 113 table (4): values of polynomial parameters corresponding to concrete compressive strengths mpa c1 c2 c3 c4 c5 c6 10 0.2708 -1.9313 5.2039 -6.6769 4.8195 0.0023 15 0.3069 -2.2018 5.9617 -7.6844 5.6319 0.0027 20 0.3390 -2.4433 6.6586 -8.6534 6.4146 0.0027 25 0.3666 -2.6403 7.1863 -9.3234 6.9258 0.0034 30 0.3784 -2.7410 7.5077 -9.8271 7.4124 0.0034 35 0.4040 -2.9094 7.9426 -10.389 7.8772 0.0036 40 0.4407 -3.1606 8.5854 -11.5854 8.3942 0.0036 . figure (1): horizontal shear forces (a) before slip. (b)after slip. figure(2): relation between clamping stress and shear strength . y = 0.6316x5 4.4973x4 + 12.012x3 14.961x2 + 9.6952x + 0.0054 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 114 figure (3): relation between clamping stress and shear strength for =10 mpa. figure (4): relation between clamping stress and shear strength for =15 mpa. figure (5): relation between clamping stress and shear strength for =20 mpa. y = 0.2708x5 1.9313x4 + 5.2039x3 6.6769x2 + 4.8195x + 0.0023 0 0.5 1 1.5 2 2.5 3 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress y = 0.3069x5 2.2018x4 + 5.9617x3 7.6844x2 + 5.6319x + 0.0027 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress y = 0.339x5 2.4433x4 + 6.6586x3 8.6534x2 + 6.4146x + 0.0027 0 0.5 1 1.5 2 2.5 3 3.5 4 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 115 figure (6): relation between clamping stress and shear strength for =25 mpa. figure (7): relation between clamping stress and shear strength for =30 mpa. figure (8): relation between clamping stress and shear strength for =35 mpa. y = 0.3666x5 2.6403x4 + 7.1863x3 9.3234x2 + 6.9258x + 0.0034 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress y = 0.3784x5 2.741x4 + 7.5077x3 9.8271x2 + 7.4124x + 0.0034 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress y = 0.404x5 2.9094x4 + 7.9426x3 10.389x2 + 7.8772x + 0.0036 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 116 figure (9): relation between clamping stress and shear strength for =40 mpa. figure (10): relation between c1 and . figure (11): relation between c2 and . y = 0.4407x5 3.1606x4 + 8.5854x3 11.159x2 + 8.3942x + 0.0036 0 1 2 3 4 5 6 0 0.5 1 1.5 2 2.5 3 s h e a r s tr e s s ( m p a ) clamping stress (mpa) relation between clamping stress and shear stress y = 0.0053x + 0.2253 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0 5 10 15 20 25 30 35 40 45 c 1 fc' (mpa) relation between c1& fc' y = -0.0386x 1.611 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0 5 10 15 20 25 30 35 40 45 c 2 fc' (mpa) relation between c2& fc' al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 117 figure (12): relation between c3 and . figure (13): relation between c4 and . figure (14): relation between c5 and . y = 0.1068x + 4.336 0 1 2 3 4 5 6 7 8 9 10 0 5 10 15 20 25 30 35 40 45 c 3 fc' (mpa) relation between c3& fc' y = -0.1431x 5.5252 -12 -10 -8 -6 -4 -2 0 0 5 10 15 20 25 30 35 40 45 c 4 fc' (mpa) relation between c4& fc' y = 0.1158x + 3.8871 0 1 2 3 4 5 6 7 8 9 0 5 10 15 20 25 30 35 40 45 c 5 fc' (mpa) relation between c5& fc' al-qadisiyah journal for engineering sciences, vol. 9……no. 1 ….2016 118 figure (15): relation between c6 and . figure (16): comparison between results of shear strength governed by present equation and others. from the results of comparison, the following conclusion points can be drawn: y = 5e-05x + 0.002 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0 5 10 15 20 25 30 35 40 45 c 6 fc' (mpa) relation between c6& fc' 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.5 1 1.5 2 2.5 3 sh e a r st re n g th m p a clamping stress mpa present equation results, fc'=20 mpa walraven equation results, fc'=20 mpa loov equation results, fc'=20 mpa loov &patnaik equation results, fc'=20 mpa article al-qadisiyah journal for engineering sciences 13 (2020) 295–300 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mushtaq.taleb@qu.edu.iq (mushtaq albdiry) https://doi.org/10.30772/qjes.v13i4.703 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. preparation and catalytic activity of co-mo/γ-al2o3 catalyst for hydro-desulfurization reaction fouad k. mahdi a , mushtaq t. albdiry b* , abbas a. diwan c a department of chemical engineering, college of engineering, university of al-qadisiyah, iraq b department of materials engineering, college of engineering, university of al-qadisiyah, iraq c nanotechnology and advanced materials research center, college of engineering, university of al-kufa, iraq a r t i c l e i n f o article history: received 14 september 2020 received in revised form 6 november 2020 accepted 6 november 2020 keywords: bimetallic catalyst hydrodesulphurization impregnation method alumina support a b s t r a c t in this study, a bimetallic como spicy supported on γ-al2o3 heterogeneous catalyst was successfully prepared by an incipient wetness impregnation for hydrodesulphurization (hds) reaction of an-najaf oil refinery heavy naphtha. the structural characteristics of the prepared 5co-15mo/γ-al2o3 catalyst were evaluated by scanning electron microscopy (sem) and x-ray powder diffraction (xrd) spectroscopies. the surface area, pore volume and pore size were determined by a brunauer–emmett–teller (bet) method. the catalytic activity in the removal of sulphur compound from a heavy naphtha through the hds at four different reaction temperatures (523, 548, 573, 598 °k) and four different liquid hourly space velocities (3, 4, 5, and 6 hr -1 ) under a constant ratio of 150 ml h2/1 ml naphtha and a hydrogen gas pressure of 1.5 mpa, has revealed that the prepared catalyst was efficient to remove 82 % of sulphur at 598 °k temperature and 3 hr -1 time. the enhanced selectivity of the como/γ-al2o3 catalyst through a hydro-treating reaction ascribes to the bimetallic-support interaction and the dispersion of mos2 particles that leaded to a large edge-to-corner ratio of comos slabs. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the increasing demand for the energy consumption has led to an increase in levels of sulphur compounds emitted from the oil refineries and this in turn has led to large challenges on the environment hamid [1]. hence, the environmental laws and restrictions have imposed on the oil refiners to produce high quality fuels with as low as sulphur contents yang et al. [2]. the oil refining is a very complex process where the crude oil passes through different chemical processes including a hydrotreating and hydrocracking, thermal cracking, catalytic reforming, fluid catalytic cracking (fcc), and hydrodesulphurization (hds) meyers [3]. the hydrodesulphurization process has shown its efficiency to remove different sulphur compounds such as hydrogen sulfide (h2s), thiols (rsh) and polysulphides (-sx 2) with the aid of catalyst at an appropriate pressure and temperature saeeded et al. [4]. the hds process is a chemical reaction using a stream of hydrogen gas to react with sulphur compounds associated with the petroleum product such as natural gas, light and heavy naphtha, diesel fuel and fuel oil james et al. [5]. the hds process is classified on of the hydrogenolysis mechanism with a c-x chemical bond, where c is carbon atom and x is a sulphur nitrogen (n) or http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 296 fouad k. mahdi, mushtaq t. albdiry, abbas a. diwan/al-qadisiyah journal for engineering sciences 13 (2020) 295–300 oxygen (o) atom, using ethanethiol (c2h5sh) to form the c-h and the hx chemical bonds as per the reaction shown in eq. 1 nigam et al. [6] c2h5sh + h2 → c2h6 + h2s … (1) one of the most applicable catalysts in the hds reaction is cobalt (co) or nickel (ni) decorated active molybdenum (mo) metal supported on a mesoporous alumina carrier hensen et al. [7]. alumina support is used to carry como or nimo spicy for its high surface area, high mechanical and thermal resistance and good chemical stability robinson et al. [8]. the co or ni metal is working as promotor for the active mo metal. the active mo metal plays a role in the hds reaction for the connection between the hydrogen gas (h2) and the oil products through the framework of mos2 and comos2 active sites on the catalyst montalvan-sorrosa et al. [9]. the activity and selectivity of heterogeneous catalyst used in the hds reaction is influenced by different parameters including the synthesis method, type of active metal and its loading percentage, type of promotor or support materials, calcination temperature, sulfidation of metal active, etc. song [10]. the efficiency of the hds reaction is also influnced by the hydrotreating operation conditions such as the reaction’s temperature, liquid hourly space velocity (lhsv), pressure, h2/oil ratio. these conditions considerably contribute in the determination of the required specifications of the oil product and the quality of feedstock thomas et al. [11]. several studies have been performed to investigate the activity of the binary como heterogeneous catalysts in the hydrodesulphurization (hds) process. for instance, chen et al. [12] determined the selectivity of como catalyst of the sulfide in the hds reaction of 4,6dimethyldibenzothiophene (4, 6-dmdbt). it was shown that the formation of comos and mos2 active connection sites resulted in a higher removal of the sulfide compounds. the use of the unsupported nimo catalyst showed a better removal of sulphide from a dibenzothiophene (dbt) through the hds process as presented by liu et al. [13]. however, understanding the activity of such catalyst in the hds reaction and obtaining a clean iraqi naphtha by changing the main operation conditions of the hds is still under consideration of research. this study aims to determine the catalytic activity of a binary como supported on alumina carrier through the hds reaction of an-najaf naphtha at four different reaction temperatures and four different lhsvs under constant pressure. it also aims to determine the chemical kinetic and the activation energy of the hds reaction of the naphtha with the use of the prepared catalyst. 2. experimental part 2.1. catalyst preparation the bimetallic como spicy supported on a gamma alumina (γ-al2o3) was prepared by an incipient wetness impregnation method as described in fig. 1. to prepare a 60 g of co5mo15/γ-al2o3 catalyst having of 5 wt. % cobalt (co) and 15 wt. % molybdenum (mo), a 14.8 g of cobaltous nitrate hexahydrate, co(no3)2.6h2o (cnh, aldrich, 99 % purity and mw = 290.93) dissolved in di (1 g: 1 ml), and a molybdenum precursor salt of 17.73 g ammonium molybdate tetra-hydrate (nh4)6mo7o24·4h2o (amh, aldrich, 98 % purity and mw = 1235.72) dissolved in deionised water, di (1g : 10 ml ratio) were used. the aqueous solution of both dissolved precursors was drop by drop impregnated on the γ-al2o3 (aldrich, mw = 101.96) carrier nanoparticles. thereafter, the wet nanoparticles were dried at 120 °c for 2 h, and the resultant impregnated material was calcined at 500 °c for 4 h. 2.2. catalyst formation after calcination, the resultant co5mo15/γ-al2o3 catalyst powder as shown in fig. 2, was mixed with 1, 3, 5, and 7 wt. % of polyvinyl alcohol (pva) as a binder followed by extrusion using a mini-screw extruder, model (caleva/uk) to obtain the catalysts' bullets with dimensions of 20 mm length and 2 mm diameter. the resultant material was heated at 50 °c for 10 h. figure 1the preparation method setup used in the study. figure 2the prepared como/al2o3 catalyst powder after calcination. 2.3. characteristics of the catalyst the synthesized bimetallic como catalyst was examined in their oxide state. the surface area, total pore volume, porosity and bulk density were measured by using brunauer–emmett–teller (bet). the crystalline structure of the active metals was investigated by using x-ray powder separating funnel three-neck flask vacuum pump ultrasonic bath https://pubchem.ncbi.nlm.nih.gov/compound/cobaltous-nitrate-hexahydrate https://pubchem.ncbi.nlm.nih.gov/compound/cobaltous-nitrate-hexahydrate https://www.sigmaaldrich.com/catalog/product/vetec/v000122?lang=null&region=null https://www.sigmaaldrich.com/catalog/product/vetec/v000122?lang=null&region=null fouad k. mahdi, mushtaq t. albdiry, abbas a. diwan /al-qadisiyah journal for engineering sciences 13 (2020) 295–300 297 diffraction (xrd) with a scan ranging of 2θ = 10 80° at a step of 0.05°. the surface morphology and structure characteristics of the prepared binary como/al2o3 catalyst were conducted by using a fesem, zeisssem model. the catalytic activity of the catalyst was evaluated through the hds reaction of an-najaf oil refinery (iraq) heavy naphtha having specifications given in table 1. table 1. properties of a heavy iraqi naphtha from an-najaf oil refinery to determine the activity of the prepared catalyst through the hydrodesulphurization reaction, a pilot plant with a fixed bed catalytic reactor designed by vinci technologies was utilized as a hydrotreating unit. the unit was designed to allow a continuous hydrogen flow up to 180 ml/h on a catalyst volume of 70 cm 3 , a temperature up to 550 °c and pressure of 150 bar. the hds reaction was performed with the use of layers from the prepared como/al2o3 catalyst (50 g) inside the stainless steel catalytic reactor while a h2 gas passes over the naphtha feedstock at a high pressure. the sulphur amount was measured after 16 different hds operations including four different temperatures i.e., 250, 275, 300, 325 °c (523, 548, 573, 598 °k) and four different liquid hourly space velocities (lhsvs) i.e., 3, 4, 5, and 6 hr -1 under constant ratio of 150 ml h2/1 ml heavy naphtha and a hydrogen gas pressure of 1.5 mpa. the percentage of sulphur removed through the hds reaction is determined using eq. 2. s (%) = 𝐒𝑭−𝐒𝑷 𝐒𝑭 … (2) where sf and sp are the sulphur amounts in the feed and the final oil product, receptivity. the x-ray fluorescence (xrf) analyser was used to measure the sulphur concentration in the feed and the final product. 2.4. kinetics of the hds reaction the chemical kinetic and the activation energy of the hds reaction of heavy naphtha with presence of the prepared catalyst were determined using the arrhenius equation as shown in eq. 3. k = k˳𝑒 −𝐸𝑎 𝑅𝑇 … (3) where k is the reaction constant (sec -1 ), ko is a pre-exponential factor (or arrhenius constant), ea is the activation energy (kj.mol -1 ), t is the absolute reaction temperature (°k) and r is the gas constant (8.314 j.mol 1 . k -1 ). the enthalpy and the entropy for the naphtha oil product was calculated by applying eq. (4). 𝐾 𝑇 = 𝐾m𝐾𝑏 ℎ 𝑒𝑥𝑝∆𝑆/𝑅 𝑒𝑥𝑝−∆𝐻/𝑅𝑇 … (4) plotting ln (k/t) versus 1/t gives a straight line with slopes equal to ( −∆𝐻 𝑅 ) and intercept equal to [( ∆𝑆 𝑅 )+ln 𝐾𝑚 𝐾𝑏 ℎ ] the slope was correlated from the obtained experimental results of the relationship between the chemical reaction and the temperature at 325 °c (598 °k) applying a second-order reaction as per eq. 5: −𝑟𝐴 = (𝑘 l s. kg cat . mol )(𝐶𝐴) 2 … (5) where k is the slope of the straight line reaction (obtained from table 3 and fig. 7), ca is the concentration of the reactant a (mol.). 3. results and discussion 3.1. physicochemical properties of the prepared catalyst the physicochemical properties of the prepared binary como/al2o3 catalyst i.e., its surface area, porosity, pore volume, bulk density, and the mean pore diameter were measured by the bet method. table 2 lists these physical properties where the surface area is 52.339 m 2 /g which is adequate to efficiently perform the catalysis of the hds reaction. table 2 also shows the elemental practical analysis of the prepared como/γ-al2o3 catalyst where the percentage of the mo active metal is 18.9 % that is fairly capable to handle the hds reaction of the heavy naphtha. these findings are in conformance with previous published studies [14], [15]. table 2. physical properties and the elemental practical analysis of the prepared binary como/γ-al2o3 catalyst. 3.2. xrd analysis the x-ray diffraction (xrd) analysis of the prepared como)/γal2o3 catalyst was performed to conduct the crystalline phases of its oxide site. fig. 3 shows the xrd pattern of the binary prepared catalyst powder. from the figure, several major peaks at 2θ values of 23° and 27° can be observed indicating the formation of (201) and (211) planes for the αmoo2 phase formed from mo 4+ ion and α-moo3 phase formed from mo 6+ ion, respectively. the other intensity peaks at 33°, 38° and 48° are attributed for the deposition of mo and co oxides on the catalyst surface such as comoo4 phase and β-comoo4 and coo deraz [19]. the highest peak at 67° or exactly 66.8° represents the (440) plane for the γ-al2o3 substrate. in addition, there are several weak intensity peaks indicating that the prepared catalyst has a nanosize particles. furthermore, by analyzing the xrd spectrum of the prepared catalyst, the crystalline structure was shown as a hexagonal structure, and the relative crystallinity percentage of the final powder was measured value specifications 72.3 api gravity at 15.6 °c 0.696 specific gravity at 15.6 °c 755 sulphur (ppm) 51.1 octane number 120 average molecular weight 30 distillation: i.p.b.℃ 167 distillation: e.p.b℃ colorless color catalyst property value catalyst content weight (%) surface area (m2/g) 52.339 al2o3 76.697 total pore volume (p/p0=0.990), cm3/g 0.1637 mo 18.929 mean pore diameter, (nm) 12.51 porosity 0.358 co 4.3739 bulk density, (g/cm3) 1.237 298 fouad k. mahdi, mushtaq t. albdiry, abbas a. diwan/al-qadisiyah journal for engineering sciences 13 (2020) 295–300 position [°2theta] (copper (cu)) 10 20 30 40 50 60 70 counts 0 500 1000 no1 following eq. 6 alrubaye [16]. the relative crystallinity (%) of the binary como/γ-al2o3 catalyst was measured to be 89.56 %, which means that the preparation method is perfect to obtain a high degree of atoms arrangement of the prepared catalyst, and resulted in a higher characteristics of the catalyst. relative crystallinity % = sum of peak intensites for samples sum of peak intensites for reference * 100 … (6) also, by using the xrd spectrum, measurement of the particle size for the prepared catalyst powder was performed by applying the scherer equation, eq. 7 rafael et al. [17]. by which, the average nanoparticle size for the prepared como/γ-al2o3 catalyst is 12.32 nm. scherer’s equation, dp= 𝟎.𝟗𝟒𝝀 𝜷𝑪𝒐𝒔𝜽 … (7) where dp is the average nanocrystalline or the mean particle size, λ is the x-ray wavelength, β is the width of line in a half the second maximum peak, and θ is the bragg angle. figure 3the xrd spectrum for prepared como/γ-al2o3 catalyst 3.3. fe-sem analysis the sem images (fig. 4) illustrate the surface morphology of the prepared bimetallic como/γ-al2o3 catalyst. it can be clearly shown that a good dispersion of the active metal mo nanoparticles and the promotor metal co nanoparticles on the mesoporous alumina carrier. this is also confirmed by the penetration and transferring of molecules between these nanoparticles with the mesoporous structure of alumina substrate mohammed [18]. in addition, there are some irregular particles and small cavities which could attribute to the gas formation which resulted in a segregation or cavity in the material. the smaller size of the catalyst powders and thereby a smaller pore diameter which in turn resulted in a larger surface area that requires to effectively complete the hds chemical reaction deraz [19]. 3.4. effect of the reaction temperature the catalytic activity of the prepared bimetallic co5mo15/al2o3 catalyst in the removal of sulphur compounds through the hds reaction was conducted in four different reaction temperatures (523, 548, 573, 598 °k) and four different lhsvs (3, 4, 5, and 6 hr -1 ) under constant hydrogen volumetric ratio and pressure. fig. 5 shows the relationship between the sulphur removed percentage (the efficiency of the hds reaction) and the reaction temperatures for four different lhsvs. it can obviously observe that the percentage of sulphur removed from the naphtha feedstock has increased with increasing of the reaction temperatures from 523 to 598 °k at the same lhsv value. for example, the sulphur removed (%) increased from 59 % at 523 ºk to 82 % at 598 ºk with the use of como/γ-al2o3 at lhsv = 3 hr -1 . the efficiency of the hds reaction enhances with the increase of the reaction temperature since the higher temperature leads to enhance the internal molecular motion and reduce the free energy (kinetic energy) that required to compete the reaction abid et al. [14]. figure 4the sem images of the prepared como/γ-al2o3 catalyst. figure 5effect of reaction temperature on the removal of sulphur through the hds at different lhsvs. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 500 520 540 560 580 600 620 s u lp h u r r e m o v e d % temperature ok lhsv=3/hr lhsv=4/hr lhsv=5/hr lhsv=6/hr β in the scherer equation https://en.wikipedia.org/wiki/bragg_diffraction fouad k. mahdi, mushtaq t. albdiry, abbas a. diwan /al-qadisiyah journal for engineering sciences 13 (2020) 295–300 299 0.3 0.4 0.5 0.6 0.7 0.8 0.9 2 3 4 5 6 7 s u lp h u r r e m o v e d , % lhsv (1/hr) t=523k t=548 k t=573 k t=548 k 100 200 300 400 500 600 700 800 900 0.1 0.15 0.2 0.25 0.3 1 /c a w.cao/fao t=523 k t=573 k t=548 k t=598 k 3.5. effect of the lhsv fig. 6 shows the percentage of the sulphur removed from the naphtha product through the hds reaction at different lhsvs and different reaction temperatures. from the figure, it can be seen that the sulphur percentage removed has decreased with the increasing of lhsv values at the same temperature. this behaviour is attributed to the increase in the lhsv values and hence increasing the flow rate of naphtha, leading to a decrease in the period time of contacting between the hydrogen gas and the oil naphtha inside the batch reactor with the presence of the catalyst [15]. figure 6effect of changing the lhsvs on the removal of sulphur through the hds at different reaction temperatures. changing of the reaction temperature and the lhsv values plays a role in the efficient completion of the sulfidation process of the oxide state of the catalyst that results in the formation of mos2 active site. the new sulphide site acts as a bridge between the sulphur compounds and the hydrogen gas. the initial temperature to start the hds chemical reaction must not exceed the range of 260 – 315 ºc to avoid coke formation which represents the first stage of the pre-sulfiding where the moo3 catalyst oxide states react with h2s. by increasing the reaction temperature, a second stage and the formation of oxy-sulphides starts alrubaye [16]. in this study, the moo3 and coo oxide sites of the prepared catalyst were pre-sulphured in h2s/h2 at temperature between 300-400 ºc. increasing the feed’s velocity of the petroleum liquid on the surface of the catalyst results in reducing the contact time required to convert the oxide site into the sulphide site as well as reducing the adsorption process of sulphur and in turn leads to disintegrate it again. this would result in returning some parts of sulphur particles with the feeder and that is lowering the sulphur removed percentage [19], [20]. 3.6. kinetics of the hds process in this study, the rate models were developed based on the conditions that is (1) the hds process follow the integral analysis model, (2) the sulphur remove reactions are irreversible and a stable density system, and (3) the influence of hydrocracking of c=c on the hds process is not essential since the reaction temperature was less than 400 ºc and higher pressure. the integral analysis to calculate the rate of the hds reaction of a heavy naphtha was used based on an ideal plug flow model. kinetics of the hds reaction to remove the sulphur from the naphtha were determined based on the second order reaction where the relationship between 𝟏/𝑪𝑨 versus 𝑾. 𝑪𝑨𝒐 𝑭𝑨𝒐⁄ was plotted as shown in fig. 7, and getting the straight line, the slope that is representing the (k ˋ ) figure 7the second order hds reaction rate of the naphtha at different temperatures based on integral analysis the activation energy (ea) as well as the enthalpy ( ∆h) and the entropy ( ∆s) energy of the hds reaction for a heavy naphtha with presence of the bimetallic como/γ-al2o3 catalyst were calculated by using eqs. 3 and 4 at different reaction temperatures (523-598 °k). the results revealed that the activation energy was (46.199 kj/mol.), the entropy energy was (-111.85 j/mol.), and the enthalpy energy was (41.56 kj/mol.). this means that the use of the prepared como supported on alumina catalyst has increased the rate of reaction and modified the transition state through the reduction of the activation energy with changing the energies of the naphtha feedstock or changing the equilibrium. a similar finding was revealed by alwan [21]. the activation energy of the como/graphene catalyst was calculated based on the integral analysis. the catalyst increases the reaction rate owing to the binding energy occurred when the substrate binds to the active site of a catalyst. the hds reaction rate constants for the como/γ-al2o3 catalyst were calculated by using eq. 5, based on the slopes obtained from the experimental results of these straight lines at different temperatures. the results of the rate constants are shown in table 3. table 3. the rate constants (k) for the hds reaction of the naphtha at different temperatures. temperature (° k) kˋ (l /s. kg cat. mol) 523 0.166 548 0.283 573 0.474 598 0.618 4. conclusions in this study, the bimetallic como/al2o3 heterogeneous catalyst was successfully prepared by a wet impregnation method for the hydrodesulphurization (hds) reaction of a heavy an-najaf naphtha. the catalytic activity of the prepared catalyst was determined at different reaction temperatures and different liquid flow rates in a pilot hds plant. https://en.wikipedia.org/wiki/active_site 300 fouad k. mahdi, mushtaq t. albdiry, abbas a. diwan/al-qadisiyah journal for engineering sciences 13 (2020) 295–300 the results revealed that the efficiency of the hds reaction has enhanced to 82 % sulphur percentage removed with the use of the catalyst at 598 ºk and 3 hr -1 . increasing of the reaction’s temperature has shown its effective on the enhancement of the hds efficiency of the naphtha feedstock. increasing of the lhsvs values has obviously revealed a reduction in the hds efficiency due to lowering of the time of contacting between the oil product and the hydrogen gas with presence of the catalyst. the surface morphology showed that the prepared active metals are uniformed dispersed on the alumina carrier substrate. acknowledgment the authors acknowledge all assistance and technical support provided by department of chemical engineering, college of engineeringuniversity of al-qadisiyah as well as the assistance submitted from the college of engineering, university of al-kufa. references [1] w. hamid, “studying of the performance of hydro rating process for mixture of gas oil and lighter fraction,” univ. technol., vol. m.sc. thesis, 2017. [2] a.j. hernandez-maladonado. and r.t. yang, “desulfurization of transportation fuels by adsorption,” cata rev, 2004. [3] meyers r., “handbook of petroleum refining processes,” mc graw-hill, 1997. [4] saeeded et al, “advents of nano catalysts in hydro treating process benefits and development,” am. j. oil chem. technol., 2004. [5] james et al, “petroleum refining technology and economic,” marcel dekker inc n. y., 2004. [6] a. kundu and d. p. nigam, “recent developments on hydro processing reactors,” rev chem eng, 2003. [7] e.j.m hensen et al., “the relation between morphology and hydrotreating activity for supported mos2 particles,” j. catal., vol. 199, no. 2, 2001. [8] paul r. robinson and geoffrey e. dolbear, “handbook of petroleum technology, hydro treating and hydrocracking: fundamentals,” springer, 2007. [9] d. montalvan-sorrosa et al, “nanotechnology applied to the bi desulfurization of fossil fuels and spent caustic streams process,” pet eng, 2016. [10] c. song, “an overview of new approaches to deep desulfurization for ultra-clean gasoline, diesel fuel and jet fuel,” catalysis today, vol. 86, 2003. [11] john meurig thomas and w. john thomas, “principles and practice of heterogeneous catalysis,” wiley, 2015. [12] chen w., long x., li m., nie h., and li d., “influence of active phase structure of como/al2o3 catalyst on the selectivity of hydrodesulfurization and hydrodearomatization,” catalysis today, 2016. [13] huan liu, quanzhen liu, jianzhong zhang, changlong yin, chenguang liu, and wangfu sun, “pvp-assisted synthesis of unsupported nimo catalysts with enhanced hydrodesulfurization activity,” fuel processing technology, vol. 160, pp. 93–101, 2017. [14] mohammad f. abid et al., “synthesis and characterization of unsupported catalyst for gas oil desulfurization,” al-qadisiyah journal for engineering sciences, vol. 11, no. 3, 2018. [15] abid m fadhil et al., “experimental study on catalyst deactivation by nitrogen compounds in a hydro-processing reactor,” arabian journal for science and engineering, 2017. [16] alrubaye, r., “generation and characterization of catalytic films of zeolite y and zsm-5 on fe cr alloy metal,” university of manchester, 2013. [17] nidia rafael and t.a. zepeda, “trimetallic ruxmoni catalysts supported on sba-15 for the hydrodesulphurization of dibenzothiophene,” international journal of chemical reactor engineering, 2018. [18] mohammed sabah mohammed, “synthesis and characterization of como/ γ –alumina and nimo/γ–alumina nano catalysts for hydrodesulphurization of gas oil",” ph.d thesis, university of baghdad, 2016. [19] nasrallah m deraz, “importance of catalyst preparation,” journal of industrial and environmental chemistry, 2018. [20] fereshtech et al, “alumina nanotube/nanorod supported desulfurization nano catalyst, method of preparation and application,” research institute of petroleum industry, 2012. [21] hameed hussein alwan, “synthesis of graphene as support for the catalysts in the hydrodesulphurization of heavy naphtha,” phd thesis, university of baghdad, 2018. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 600 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. high altitude platform stations in design wireless communication system for cover the specific area yousif mohsin hasan, university of al-qadisiyah, college of engineering, iraq. e-mail: yousif.hasan@qu.edu.iq received on 24 october 2017 accepted on 13 december 2017 published on 15 march 2018 doi: 10.30772/qjes.v10i4.490 abstract: this paper explains how to design a wireless communication system via high altitude platform stations haps to cover the specific area (using diwaniyah city area as a model). high altitude platform station haps is unmanned airplane provides the wireless communication service to the wider area. it is designed to work at high altitude between (17-22 km) and coverage area 400 km. this study illustrated for calculating the cochannel interference between haps ground station with a terrestrial station and satellite station. free space losses for a haps ground station has been applied to meet the geographic of diwaniyah city. in addition, explaining the relationship between elevation angles with the radius of the coverage area. interference mitigation techniques have been given, such as improving the antenna radiation pattern, then it proposed the elevation angle for the haps's ground stations to reduce an interference between haps network with fixed service (fs) and fixed satellite service (fss). finally, this study explains the relationship between elevation angles with the radius of the coverage area. for more reliability, the scenario for covers the city of diwaniya. two ground stations have been proposed to connect with high-altitude platform station. keywords: wireless communication system, high altitude platform stations (haps) , cochannel interference, interference to noise ratio i/n, separation distance, haps coverage area. introduction high altitude platform stations (haps) is one of the new technologies that provide the wireless communication service. this technology can be performing the service of the terrestrial station and satellite system. the service of high altitude platform station (haps) includes wireless communication, broadband communication, weather monitoring, security monitoring and data of city map collection. the high-altitude platform station (haps) is situated between 17 and 22 km above ground [2]. haps coverage area about 200 km to 500 km depend on the specific area which has been chosen to design these technologies [12]. one of the advantages of using high altitude platform station can provide a wide coverage area. single haps can be covering an area equivalent to 258 ground terrestrial towers [1]. high altitude platform station technology has been several advantages compared with satellite and terrestrial services such as low propagation delay compares with satellite and wide area coverage compare with terrestrial services [9]. haps coverage area, depending on the altitude of haps and the elevation angle. (figure 1) describes how haps can carry a large variety of wireless communications payload which provide a high capacity of endusers of broadband service. mailto:yousif.hasan@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 601 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1: network architecture of haps [10]. 1. interference mitigation technique thus, general interference mitigation techniques must be taken into our consideration for the development of a system using haps [5]. 1.1. increasing the minimum elevation angle (elv. angle) "interference from the fixed satellite service (fss)"[5] ground station to the haps ground stations that between fs ground stations and haps ground station can be reduced by increasing the minimum elevation angle of the haps ground station. 1.2. improvement of radiation patterns of antenna stations this technique can be reduced interference from haps airship to the space satellite part by forming a pattern of each beam of a multi beam antenna on the board haps airship, (figure 2) explains the pattern shaping improves the main lobe and side lobes characteristic [6]. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 602 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: main lobe and side lobes characteristic (improvement antenna radiation pattern). 1.3. dynamic channel assignment (dca) it is to reduce the interference; this mitigation is to search un-use frequencies, not to give interference to another service and not so as to be received from another service. when wireless communication system operating base on demand assignment, dca scheme is using self-control ineffective for sharing with another service. [4] 1.4. automatic transmission power control (atpc) in the wireless communication system use a high-bandwidth, and system design consider the attenuation of rain. to compensate for attenuation, is to increase the transfer of power from the rain value. atpc has the potential to control the production of energy in monitoring the weather or receive power. transmission power is increasing with rain condition and its decreasing with clear sky condition [5]. 2. haps interference and free space loss evaluation for the calculation interference from the haps ground stations to fwa stations used following equations. "the interference from haps ground station to an fwa station is obtained by the equation (1)" [13] (1) i is interference, gstx p _ transmission power for haps's ground stations in (db), gsftx l _ feeder loss of haps ground station (db), )( __ fhgstx g  antenna gain of haps ground station , s l free space path losses between fwa stations and haps ground station (db), al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 603 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. atm l atmosphere absorption loss between haps ground station and fwa station(db), )( __ hffwarx g  receiving antenna gain of fwa station (dbi) and fwafrx l _ is the feeder losses in fwa stations (db). the free space path losses between haps ground stations and fwa stations is given by equation (2) (2) where d is the distance between haps and fwa station in (km), is a wavelength in (m) and the interference to noise ratio (i/n) was obtained by equation (3) [8]. (3) where k is boltzmann constant = 1.38 × 10^-23 (j/k), nf is noise figure (db). 3. methodology 3.1. location diwaniyah coordinates longitude 31°59'15"n and latitude 44°55'42"e, according to the map of diwaniyah city. the location of haps to the center of the coverage area after studying these area is shown in (figure 3). according to the whole area of diwanyiah city, the footprints of coverage area shown in (google map), the area of diwaniyah city center is (1212 sq. km). 3.2. system parameters the parameters of haps and fs systems are summary in (table 1) to covering a diwaniyah city area. in (table 1) shows the angle and corresponding ground coverage area have been measured from nadir. table 1: parameters of haps system. haps altitude 20 km antenna gains of a haps ground station 35 dbi availability of haps system 99.4% minimum elevation angle of haps ground stations 30° estimated number of haps 1 required eb /n0 for ber  1  10 6 5.5 db link margin of haps system 3 db al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 604 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3: haps coverage area in diwaniyah city’s map. 3.3. altitude selection for haps system the major challenge on the altitude selection for haps is the wind speed. an operating altitude of haps between 17km and 22 km because the wind speed is the minimum as shown in (figure 4) [14]. at altitudes of 20 km, the air masses can be considered relatively stationary with very slow winds. the altitude of haps depends on wind speed. in this case it was chosen altitude of haps to diwaniyah city center is above 20 km it is enough to cover this area. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 605 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: wind speed (m/s) vs altitude (km) [14]. 3.4. haps coverage area the coverage area of the high altitude platform station (haps) is depending on altitude and elevation angle of the antenna. one haps airship can be offer remarkable coverage measurement 400 km distance of the ground area instead of 258 ground terrestrial towers [2]. (figure 5) have been plotted with matlab program, it explains the relationship between the elevation angle and the radius of the coverage area. reducing elevation angle lead to increase the radius of the coverage area it is an inverse relationship. from table1. the elevation angle of the haps ground station for diwanyiah city using the uac coverage area will be at 30°, 60° and 90° with altitude 20 km, so the distance of the haps ground station will be: al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 606 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: radius vs elevation angle at altitude 20 km. 3.5. interference to noise ratio i/n under clear sky condition to calculate interference to noise ratio i/n must find the free space loss ls by using equation (2) and calculate interference power (i) using equation (1). (figure 6) show the antenna pattern for the haps ground station while the typical link budget for the haps system is given in (table 2) used 28/31.28ghz under clear sky conditions [13]. both (table 2) and (figure 6) are adopted the value of parameter regard the haps ground in equation (1). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 607 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 6: haps antenna pattern. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 608 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 2: link budget for haps system at 20km altitude, clear sky conditions [13]. both (table 3) and (figure 7) are using to obtain the value of a parameter regarding fwa base station. after calculating interference, can be computed interference to noise ratio i/n using equation (3). up link down link up link down link elevation angles (in degree) 20º 90º frequency(f) 31.28ghz 28ghz 31.28ghz 28ghz bandwidth(bw) 20mhz 20mhz 20mhz 20mhz transmition ofantenna:  power o/p (dbw) 16.3 14.5 16.3 15.2  feeder losses(db) 0.5 0.5 0.5 0.5  gain(dbi) 35 29.5 35 16.5  e.i.r.p.(dbw) 18.2 14.5 18.2 0.7  e.i.r.p(db(w/mhz)) 5.2 1.5 5.2 12.3 path length(km) 58.50 58.50 20.0 20.0 free space path losses (db) 157.7 156.7 148.4 147.4 rain atténuation (db) 0 0 0 0 availability in the zone m (%) 100 100 100 100 atmospheric gases attenuation (db) 0.4 0.4 0 0 pfd(db(w/m 2 · mhz)) / 105.2 / 109.3 receiving antenna:  gain (dbi) 29.5 35 16.5 35  feeder losses(db) 0.5 0.5 0.5 0.5  received power (dbw) 110.9 108.1 114.2 112.2  noise temperature in(k) 700 500 700 500  noise temperature in(db(w/hz)) 200.2 201.6 200.2 201.6  interference power(db(w/mhz)) (i/n = 10%) 150.2 151.6 150.2 151.6  receiver losses technical (db) 2.5 2.5 2.5 2.5 c/n0 available (db(hz)) 86.30 90.60 83.00 86.50 userdatarate udr (mbit/s) 13.3 13.3 13.3 13.3 userdatarate udr (dbhz)) 71.2 71.2 71.2 71.2 required eb/n0(db) (ber for qpsk =106) 10.50 10.50 10.50 10.50 coding gains(db) (k =7, r =2/3) 5 5 5 5 necessary eb/n0 (db) 5.5 5.5 5.5 5.5 necessary c/n0 (db(hz)) 76.7 76.7 76.7 76.7 linkmargin in (db) 9.60 13.90 6.30 9.80 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 609 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table 3: parameters of fwa station. parameters 31.28 ghz 28 ghz transmitting o/p (in dbw) 3.0 3.0 spectral density o/p (in db( w/ mhz)) 6.0 6.0 noise figures (db) 7.0 8.0 receiving thermal noise calculating (in db(w/ mhz)) 137.0 136.0 antenna gains (indbi) 37 / 46 36 / 46 antenna pattern depend on reco.itu_r f1245 reco.itu_r f1245 feeder losses (db) zero zero modulation type 4-fsk. qpsk. figure 7: antenna beam pattern in azimuth direction. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 610 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4. result and discussion using matlab to plot and analysis the graphs for showing the relationship between interference to noise ratio (i/n), separation distance(d) and the azimuth angles in clear sky condition shown in (figure 8). the main importance in this survey is to get minimum separation distance necessary to optimize interference to noise ratio, it will be -10db. subsequently, the analysis is performed on this graph. (figure 8) shown the graph of interference to noise ratio i/n versus distance between haps ground station and the ground station for various azimuths in clear-sky condition. it includes the azimuth angles are 30°, 60° and 90° from (figure 8), can be seen that interference to noise ratio i/n is decreased when the separation distance d is increasing for various azimuth. a minimum separation distance has been required to obtain the optimum interference to noise ratio i/n for the azimuth of 30°, or any azimuth less than 40°, is 188 km. for azimuth of 60°, 119 km is needed. finally, optimum interference to noise ratio i/n at an azimuth equal to 90°, the minimum separation distance is 53 km. figure 8: i/n vs separation distance for various azimuth in clear sky condition. the results obtained require to install tow ground stations with elevation angles 30° and 60° assuming the location of fixed service (fs) and fixed service satellite (fss) to avoid the interference between haps ground stations and (fs, fss), location of the haps ground stations will be at (d1 and d2), the interference with fs and fss stations decrease because user starts to go out of the haps coverage area and transmission power of terrestrial station is getting high there for quality of service to improve the chances of coexistence. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 611 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. conclusion in this paper, have been given in the review of haps and the benefits of using haps in the wireless communication system in the specific coverage area. scenario covers the city of diwaniya, it has been proposed in addition to the two ground stations to communicate with high altitude platform station for more reliability. the mitigation technique has been used to reduce interference to noise ratio i/n, when the fixed station fs and fixed satellite station fss is separately away from the haps ground station. most interference exists when the elevation angle from haps towards (fss/gs, fs/gs) stations is equal to the elevation angle from haps towards haps ground station; the larger gain of fixed satellite station (fss) and fixed station (fs) lead to reduce interference. furthermore, the free path loss has been calculated depending on the coverage area of diwaniyah city. the network of haps will be covering a whole city area of different wireless communication service. references 1. al-samhi, s. h. a., and n. s. rajput. "interference environment between high altitude platform station and fixed wireless access stations." system 4 (2012), 5. 2. alsamhi, saeed h., and n. s. rajput. "an intelligent hap for broadband wireless communications: developments, qos and applications." international journal of electronics and electrical engineering 3.2 (2015), pg. 134-143. 3. alsamhi, s. h. a., and n. s. rajput. "methodology for coexistence of high altitude platform ground stations and radio relay stations with reduced interference." international journal of scientific & engineering research 3 (2012),pg. 1-7. 4. cuevas-ruiz, josé luis, alejandro aragon-zavala, and beatriz bautista-leon. "co-channel interference for terrestrial and haps systems in a cellular structure." electronics, robotics and automotive mechanics conference, 2009. cerma'09.. ieee, 2009. 5. itu-r f.1569, “technical and operational characteristics for the fixed service using high altitude platform stations in the bands 27.5-28.35 ghz and 31-31.3 ghz”, (2002). 6. itu-r recommendation f.1501, “coordination distance for systems in the fixed service (fs) involving highaltitude platform stations (hapss) sharing the frequency bands 47.2-47.5 ghz and 47.9-48.2 ghz with other systems in the fixed service”. 7. itu-rf.1500, “preferred characteristics of systems in the fixed service using high altitude platform operating in the bands 47.2-47.5ghz and 47.9-48.2 ghz”,( 2000). 8. karapantazis, stylianos, and f. pavlidou. "broadband communications via high-altitude platforms: a survey." ieee communications surveys & tutorials 7.1 (2005),pg 2-31. 9. matolak, david w., and ruoyu sun. "unmanned aircraft systems: air-ground channel characterization for future applications." ieee vehicular technology magazine 10.2 (2015),pg. 79-85. 10. tariq, k. r., majed, m. b., & hamid, z. a "design of wireless communication system to cover specific area by using haps". uhd journal, 1(3) .(2016), pg. 357-361. 11. tozer, t_c, and david grace. "high-altitude platforms for wireless communications." electronics & communication engineering journal 13.3 (2001), pg. 127-137. 12. zeng, yong, rui zhang, and teng joon lim. "wireless communications with unmanned aerial vehicles: opportunities and challenges." ieee communications magazine 54.5 (2016),pg. 36-42. 13. f.1609 : interference evaluation from fixed service systems using high altitude platform stations to conventional fixed service systems in the bands 27.5-28.35 ghz and 31-31.3 ghz,(2003). 14. https://electronicsforu.com/technology-trends/wireless-communication-using-high-altitude-platform/2. 15. qucomhaps malaysia official website http://www.qucomhaps.net/. https://electronicsforu.com/technology-trends/wireless-communication-using-high-altitude-platform/2 http://www.qucomhaps.net/ الخلاصة 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 1 mathab newton-raphson method abstract: this research aims to design and implement a computer program to analyze the load flow using the mathab. this program is used to calculate the value of the load and the direction of flow in the system by calculating the final values of the bus bar voltages using (newton-raphson method) and then of fuzzy logic to analyze the load flow in the electrical power system to detect and distinguish the uncertain inaccurate values, and confirmed in normal values type bus-bar gauss-seidel method newton –rap son method decoupled load flow method fast decoupled load flow method inter connected power system) node bus-barbranches 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 2 generator bus-bar load bus-bar 1 active power (reactive power losses power2 stability analysis [1,2] 1-bar-load (pq) bus pq 2 bar-) bus│v│voltage controlled(p pv q  3-)bus slack(reference ,swing v 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 3 1 1[3,4,5] graded member ship universe of discourseumember shipnon-member1full member fuzzy logic set µxiu 0,1member ship xitfuzzy set [7.6] t (xn)/xn ………(1)t(x2)/x2+………..µt(x1)/x1+µtt= µ   n i xixi 1 )/( µt= where i=1,2,3…….n (power system) 5(bus-bars) )(102 (load flow program) -1(pq bus-bar -2 vpbar-bus 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 4 -3 (slack bus-bar) -4(flow power) -5(losses power ) (3 matlab.7) (taylor`s series) (real equations) (p) )42...(.................................................................................................... )32.(............................................................ )32.........(.................................................. )22.........(.............................. )12..(................................................................................ 1 ***        qps vvvv vvvv yyyy yvvivs ppp qqqqqqq ppppppp pqpqpqpqpqpqpq pq n q qppqpp j bsinjcos asinjcos jbgsinjcos    (2-1) )52........(........................................).........( 1     pqpq n q pqqppp yvvqp j 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 5 )72.(........................................).........( )62..(........................................).........( 1 2 1 2           pqpq n pq q pqqpppp k p pqpq n pq q pqqpppp k p sin cos yvvbvq yvvgvp g pp b p p  pqq-p y pqq -p  pp  qq -1(ybus matrix)5 2p pq p6-2 2-7 3 (specified value) (calculated value) )92..(...................................................................... )82..(...................................................................... )()( )()(   qqq ppp k calculatedpspecifiedp k p k calculatedpspecifiedp k p  -4(jacobian matrix): )3(.................................................................................................... 43 21          jj jj j kk kk k 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 6 j 1j 2j 3j 4matrix)-(sub j 1 (off-diagonal elements) asin pqpqpqqp q p yvv p )13...(..................................................).........(      (diagonal elements) bsin pqpq n pq q pqqp p p yvv p )13(..................................................).........( 1         j 2 acos pqpqpqpq q p q yvv v p v )23.(........................................).........(     bcos pqpq n pq q pqqpppp p p p yvgvv v p v )23......(..........)]........(2[ 1        j 3 acos pqpqpqqp q p yvv q )33......(........................................).........(      bcos pqpq pq q pqqp p p yvv q )33(..................................................).........( 1         j 4 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 7 asin pqpqpqpq q p q yvv v q v )43.........(....................).........(     bsin pqpq n pq q pqqpppp p p p yvbvv v q v )43.....(..........)]........(2[ 1        5p )53.(................................................................................ 43 21                                   v v jj jj q p p k p k p kk kk k p k p  6pk+1 b a vvv k p k p k p k p k p k p )63........(................................................................................ )63.(.......................................................................................... 1 1      7(flow power) 8(losses power) 8292 92-1 power -1 (universe of discourse) loadgen l≤ x≤ l 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 8 l, -l (u) 30≤ pg ≤-10 ≤ pq ≤ 50 -5 4 67 -2 plpg v5is if pl is very low &pg is very low then -3 voltage magnitude voltage angle 3 4 -1 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 9 ( أنواع قضبان التوصيل العمومية1شكل رقم) ( بيانات قضبان التوصيل العمومية1جدول رقم ) unknown quantity known quantity bus-bar type no. p,q , v  slack 1 , q  p,v voltage controlled 2 , v  p,q load 3 slack bus-bar pq bus-bar t.l.2 t .l .1 t.l.3 vp bar-bus babarcont rolled 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 10 ( نظم القدرة الكهربائية المعدة للتحليل2شكل رقم ) y-bus matrixشكل مصفوفة السماحية ضع جميع الفولتيات بقيمتها األبتدائية slack bus-barادخل رقم عمومي المرجع k= 0 (j) شكل المصفوفة اليعقوبية علةاحسب القدرة الفعالة والمتفا )( )( 1 2 1 2   pqpq n q pqqpppp k p pqpq n q pqqpppp k p sin cos yvvbvq yvvgvp       هل ان   qp , اطبع النتائج احسب البيانات الخارجة النهاية احسب التغير في القدرة الفعالة qqq ppp k calcpspsp k p k calcpspsp k p .)(.)( .)(.)(   كال نعم عادلة اآلتيةحل الم                         q p j v k p k pk k p k p 1 احسب قيمة وزاوية الفولتية عند كل عمومي حمل وزاوية الفولتية عند كل -عمومي متحكم بالفولتية من المعادلة اآلتية: vvv k p k p k p k p k p k p     1 1  البداية 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 11 رافسن –( المخطط األنسيابي لطريقة نيوتن 3شكل رقم ) نيوتن طريقةرافسن 0.99 1 1.01 1.02 1.03 1.04 1.05 1.06 1.07 0 0.5 1 1.5 2 2.5 التكرارات عدد )p .u ة) قيم ة تي ول لف ا نيوتن طريقةرافسن 0.99 1 1.01 1.02 1.03 1.04 1.05 1.06 1.07 0 0.5 1 1.5 2 2.5 التكرارات عدد )p .u ة) قيم ة تي ول لف ا ة الفولتية مع عدد التكرارات في منظومة القدرة (: تغير قيم4شكل رقم )                       21.1175.37500.32500.10000.000000.05000.75000.2000.0000.0 00.000.0695.3891667.12000.30000.10000.566667.1000.0000.0 00.000.0000.30000.10695.3891667.12000.566667.1750.3250.1 50.750.2000.566667.1000.566667.1415.3283334.1000.1500.5 00.000.000000.000000.07500.32500.10000.15000.5695.1825.6 jjjjj jjjjj jjjjj jjjjj jjjj y buss ( y-bus matrix)( مصفوفة السماحية 5) شكل رقم بيانات الشبكة الكهربائية الالزمة لتحليل تدفق الحمل (1جدول رقم) bus type assumed voltage vp(p.u) reactive power gener. qg(p.u) real power gener. pg(p.u) reactive load demand qd(p.u) real load demand pd(p.u) bus code (p) slack 1.06 0 0.00 0.00 0.00 0.00 1 اجعل vv k p k p k p k p 11 ,   1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 12 pq 1.00 0 0.10 0.20 0.30 0.40 2 pq 1.000 0.15 0.45 0.00 0.00 3 pq 1.00 0 0.05 0.40 0.00 0.00 4 pq 1.00 0 0.10 0.60 0.00 0.00 5 رافسن -فولتية القضبان العمومية لكل تكرار بأستخدام طريقة نيوتن (6جدول رقم) bus – bar voltages iter. cou. bus – bar 5 bus – bar 4 bus – bar 3 bus – bar 2  0 p.u v  0 p.u v  0 p.u v  0 vp.u 0.00000 1.00000 0.00000 1.00000 0.00000 1.00000 0.00000 1.00000 0 -6.27679 1.03274 -5.40269 1.03598 -5.05703 1.03582 -2.76260 1.05664 1 -6.15410 1.01817 -5.33308 1.02375 -5.03434 1.02435 -2.81072 1.04777 2 6 vh hml maxminmaxminmaxminmaxmin 300.4620 .48 0.420.43 0. 0.375-10pg 500.280.30.210.220.080.1-5pq 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 13 7 (يمثل الشكل التوضيحي لحساب قيمة الفولتية وزواية الفولتية8شكل رقم ) 1122 3العدد 4المجلد لهندسيةامجلة القادسية للعلوم 14 المصادر:1 1994 2-weedy,b.m and cory, b.j , ”electrical power system”,4 edition, john wiley and sons ltd,england,1998. . 1990 4gupta , b.r ,” power system analysis and design ”, second edition, tata mc-graw-hill publishing, new-delhi ,1998. 5-arrillaga,j.and watson, n.r, ”computer modeling of electrical power systems”, second edition, john wiley and son, england , 2001. 6l. a zadeh. .fuzzy sets.. international journal of information and control, vol 8, 1965. 7george.j.klir and tina a. folger, "fuzzy sets, uncertainty and information", prentice. hall binghamton, 1988 book. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 211 experimental performance of reinforced concrete hollow columns exposed to fire dr.thaar saud salman al-gasham civil engineering department, college of engineering, university of wasit. e-mail: dr.thaaralgasham@yahoo.com, mobile: 07813053254. received 10 january 2016 accepted 21 february 2016 abstract this paper experimentally investigates the effect of high-temperature fire on the structural behavior of reinforced concrete hollow columns. sixteen square (120×120mm) columns were fabricated with 600mm length. the experiment's parameters were: the hollow size and the temperature of fire. twelve specimens were cast with a hollow cross-section by inserting pvc pipes centrally along their length; these columns were categorized into three groups depending on the hollow diameters: 25.4, 50.8, and 76. 2mm. the remaining samples were solid and gathered in one group. each group contained four samples; three of them were burnt at 300, 500, and 700 o c for one hour, and the fourth one was a reference not exposed to fire. all columns were tested under an axial compressive loading applied progressively up to the column’s collapse. the experiment results indicated that the collapse load of columns, having a same cross-sectional area, decreased with increased the temperature. the decline in columns’ strength ranged from 20.00% to 68.67% for specimens exposed to 300-700 o c temperature, respectively. additionally, for columns exposed to the same temperature, the collapse load descended as the hollow size augmented. a decrease of failure load varied from 21.86% to 65.38% for 25.4 to76.2mm hollow size columns, respectively. finally, columns' stiffness reduced with increasing the temperature and the hollow size. keywords: hollow columns, fire exposure, temperature, collapse load, axial stiffness. معدة الررانية الدلحة ألدجفة ألدررة أل ألان ألأالداء ألتجريبي ل د.ثنئر ارفد احدنن الغشنمم. كحة الهاةا / جنمر وااط ألرالص تجريبيا تأثير الحرارة المرتفعة على السلوك االنشائي لالعمدة الخرسانية المسلحة المجوفة. تم أنشاء ستة عشرة عمود البحث يتحرى ملم . متغيرات التجربة كانت كال من حجم التجويف و درجة الحرارة . اثنى عشر 011ملم وبطول مقداره 021× 021بعاد مربع با مركزيا على طول العينة. تم تصنيف هذه العينات باالعتماد على قطر (pvc) عينة كانت مجوفة من خالل مد أنبوب بالستيكي mailto:dr.thaaralgasham@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 212 ج المتبقية كانت ذات مقطع صلد و جمعت في مجموعة واحدة. كل مجموعة تحتوي على النماذملم(. 20.2و 1.5.و 2..2االنبوب ) ْم ( والنموذج الرابع هو نموذج مصدري لم يتعرض 211و 11.و 011اربع نماذج, ثالث منها معرضة الى درجات حرارة مختلفة ) الى حد الفشل. نتائج التجربة يجيا على النموذج سلط تدرمالى النار. جميع االعمدة تم فحصها من خالل تسليط حمل انضغاط محوري شل بحمل يتناقص مع ازدياد درجة الحرارة. ان النقصان في مقاومة االعمدة فبينت ان االعمدة ذات المقطع العرضي المتشابه ت االعمدة باالضافة الى ذلك ان ْم. 211الى 011% عند تعرضها الى درجة حرارة تتراوح من 05.02% الى 21من تترواح % 20.50المعرضة الى نفس درجة الحرارة فشلت بحمل يتناقص مع ازدياد حجم التجويف. حيث تغير االنخفاض في حمل الفشل من ملم. أخيرا, ان صالبة االعمدة تنخفض مع ازدياد كال من درجة 20.2ملم الى 2..2تجويف يتراوح من % لالعمدة ذات 05..0الى . وحجم التجويف الحرارة 1. introduction the hollow reinforced concrete columns are desirable to employ in constructions, especially in seismic zones because of minimizing the superstructures’ weight and subsequently the seismic response. the using of hollow columns reduces the loadings transferred to foundations; hence smaller foundations are required. therefore, hollow columns are an economic choice in areas where the concrete cost is comparatively high. finally, the hollow columns allow easy to access different services like pipes for electric wiring and plumbing (kim et al., 2012). the exposure to high temperature is one of the risk issues facing the constructions. the structural elements should be designed with an adequate resistance to fire in order to protect the structures from a collapse, or at least, provide suitable time for occupants to escape before the collapse. the columns are the most important elements in constructions since they shore the structures and carry the loads to the footings. therefore, any column deterioration may lead to a partial or complete collapse of the structure (sakai and sheikh, 1989). the local and international areas have seen many studies investigating the effect of fire exposure on the structural elements, especially for columns. in 2005, kodur et al., examined the behavior of three confined reinforced concrete columns using fiber -reinforced polymer (frp) sheets and exposed to fire. the cross-sections of two specimens were circular (400 mm in diameter), and the third specimen was square (406 mm in width). the length of three columns was 3810mm. the experimental results observed that the frp sheets were sensible to the influences of high temperatures and needed a suitable fire protection. the well protected strengthened columns performed structurally better than the unstrengthened columns. the behavior of axially loaded reinforced self-compacting concrete was investigated experimentally by izzat in 2012. twelve columns were exposed to various temperatures (300, 500, and 700 o c); two methods for cooling were used; gradually by air and suddenly using water spray. the results revealed that the failure loads of the column decreased with increasing the temperature. the ultimate strength of the suddenly cooled specimens was 10% lesser than that of gradually cooled columns. kadhum in 2013, examined experimentally the influences of temperature, load eccentricity, concrete strength, and spacing of ties on the structural performance of 120 columns. the results showed that the ultimate capacity of specimens decreased significantly when burning with fire flame. the effect of fire exposure was more severe for columns tested under loads of high eccentricity. an increase in the ties spacing caused an increment in the maximum crack width. bikhiet et al. in 2014, presented an experimental and theoretical study conducted on the r.c short columns exposed to fire. in this study, fifteen specimens were constructed to investigate the effect of al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 213 concrete grade, duration of fire, steel strength and the percentage of the main reinforcement. the major conclusion was that the specimens exposed to fire failed at loads 20-40% smaller than that corresponding unexposed specimen. the specimen constructed with high-grade steel failed at load 55% higher than that of the column with mild steel. using the water jet in cooling down the column reduced the residual strength by 17% compared with the column cooled gradually. in the same year, the fire performance of lightweight concrete columns was presented by el-shaer. the lightweight concrete was made of expanded clay aggregate; four specimens were constructed. the specimens were exposed to elevated temperature and subjected to an axial load. the results illustrated that the ultimate capacity and stiffness of the unexposed light weight columns reduced slightly compared with normal-weight columns. perversely, the load carrying capacity of the lightweight specimens enhanced after exposing to high temperature, the author did not show the cause of this conclusion. echevarria et al. in 2015, studied the performance of protected concrete-filled fiber-reinforced polymer tube and conventional reinforced concrete (rc) bridge columns after exposing to fire. the specimens were similar in the axial and flexural strengths, and the study parameter was the duration of the high temperature (one and two hours). the conventional rc columns showed lower axial strength and stiffness retention compared to the protected columns after fire exposure. although of increasing the use of hollow section columns in constructions, there is a lack of experiments conducting on the hollow columns subjected to elevated temperatures. the current paper aims at fill this gap by introducing an experimental program. the program explored the influences of hollow size and temperature level on the structural performance of r.c hollow columns. 2. test column specimens in order to evaluate the effect of fire exposure on the structural performance of r.c. hollow section columns loaded axially, sixteen specimens were manufactured and tested in the concrete laboratory in the engineering college of wasit university. the specimens were square in the cross-section with dimensions of 120 ×120 mm; their length was 600mm. all columns were reinforced longitudinally with four deformed bars of 10mm diameter. the bars were positioned at the ties’ corners. the transverse reinforcement consisted of 6mm in diameter ties spaced at a distance of 120mm center to center as sketched in figure (1). the yield strengths of main and tie reinforcement, obtained from test, were 436 and 381 mpa, respectively. the test variables were the hollow size and the burning temperature. four columns were solid and gathered in the first group. the remaining twelve specimens were fabricated with circular hollow sections by inserting pvc pipes longitudinally through the specimens’ center; they were classified into three groups in accordance with the pipe diameters: 25.4, 50.8, and 76.2mm, respectively. each group contains four specimens, table (1). in all groups, three columns were burnt at 300, 500, and 700 o c temperature. the fourth specimen was kept without the fire exposure and kept at room temperature (25 o c) as a reference specimen. the columns were designated by letter c followed by two numbers separated by hyphen symbol (-). the first number refers to the hollow diameter divided by 25.4 while the second one refers to the burning temperature divided by 100 (i.e. the designation c3-5 refers to a column having a hollow al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 214 diameter equal to 76.2 mm and burnt at 500 o c temperature.). the second number for control specimens was set as (0). a one concrete mix design was utilized throughout the experimental investigation. it composed of ordinary portland cement, sand, and crushed gravel (10mm maximum size) in the following weight proportions 1:1.7:2, respectively. the water to cement ratio was 0.54. the specimens of each group were cast in one concrete batch, three standard cubes (150×150×150mm) were taken to assess the compressive strength of batch, table (1). before the casting of columns, the pvc pipes were put centrally inside the reinforcement cages as shown in figure (2). then, the cages were placed inside wood moulds leaving a clear concrete cover of 10mm from all sides. the columns were casted in the side position. a good compaction was guaranteed using a vibratory table. 3. burning and testing after completing the curing period (28 days), the twelve column specimens were burnt inside a diesel furnace with 770×520×450 mm dimensions. the columns were divided into three batches (four specimens for one batch). each batch was burnt separately to a target temperature for one hour. the target temperatures for three batches were 300, 500, and 700 o c, respectively. the temperature inside the furnace was monitored through the furnace digital screen. next accomplishing the burning process, the furnace was turned off and its door was opened. the specimens left inside the furnace to cool gradually as shown in figure (3). then, the specimens were taken out, and their surfaces were examined accurately. cracks distributed randomly were noticed, they became deeper and more numerous for specimens exposed to the higher temperature as shown in figure (4). moreover, these samples displayed a concrete cover spalling off, especially at their corners. the burnt columns were kept at a room temperature before the testing. finally, all specimens (burnt and references) were subjected to an axial loading; the eccentricity of load was carefully avoided. the load was applied gradually using a universal machine (150 ton capacity) up to the specimen’s failure. two steel plates were inserted between the specimen ends and the testing machine to avert the problem of stress concentration. a dial gauge of 0.01 mm accuracy was employed to measure the axial displacement of specimens as shown in figure (5). 4. discussion of experiment results the test results are discussed in three terms: mode of failure, ultimate strength of columns, and loadaxial displacement response for all samples as following. 4.1. mode of failure the unexposed reference samples displayed, firstly, tiny cracks in the outer thirds of their length. the first cracks initiated at loads of 120, 100, 75, and 50 kn for samples c0-0, c1-0, c2-0, and c3-0, respectively; their number, depth, and width increased rapidly as the applied load increased. they developed preliminary vertically parallel to the samples’ longitudinal axis, and thereafter they inclined toward the column’s corners. at a collapse, the samples experienced a concrete crushing at the al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 215 specimen’s ends, where the stress concentration was relatively high. on the other hand, the largest hollow size sample, c3-0, spilled longitudinally at collapse load as illustrated in figure (6). there was a difficulty in recording the cracking loads of fire-exposed specimens. since they displayed, during burning, tiny cracks spreading arbitrarily on the samples’ surfaces. generally, they suffered concrete crushing occurring on wider area compared with unexposed similar columns. the concrete cover spalling was observed at earlier loads, where concrete fell down as a powder, especially for specimens burnt at 700 o c. at the failure, a complete cover spalling of at corners, and concrete crushing were noticed in the burnt columns as displayed in figure (7). furthermore, the largest hollow burnt specimens did not exhibit a longitudinally split, on the contrary unexposed reference column c3-0. 4.2. ultimate strength of columns the ultimate axial loads for all samples are summarized in table (2). the fire exposure strongly influences the column load capacity, where the increase in the exposure temperature decreased the column strength as plotted in figure (8). this can be imputed to the following reasons accompanying with elevated temperatures: the loss in a concrete strength contributing a large percentage of the columns' strength, especially for those loaded axially. the second reason is the spalling of a concrete cover leading to minimize the columns' cross-section area. thirdly, a damage in the bond strength between the reinforcement steel and the surrounding concrete besides a deterioration of the interconnection between the concrete components as the result of a formation of earlier fire cracks. the final cause is the expansion of the main reinforcement as well as the shrinkage of the concrete during fire exposure. in group one including solid specimens, reductions in the load capacity of 21.82%, 34.55%, and 52.73% were recorded for specimens c0-3, c0-5, and c0-7 exposed to 300, 500, and 700 o c compared to the unburned specimen c0-0, correspondingly. the decreases in the columns' strength, at 300, 500, and 700 o c, were :20.00%, 38.10% and 53.81% for 25.4mm hollow columns, 26.67%, 46.67%, and 62.00% in columns of a 50.8mm hollow, and 18.18%, 40.91%, and 59.09% for largest hollow columns, comparing with the corresponding unexposed columns, respectively. it is worth mentioning that the columns’ load capacity declined approximately linearly with raising the temperature as illustrated in figure (8). the best-fitting linear equations, representing the variation of column strength with temperature, were derived using a computer program (excel 2013), as follows. for solid specimens, y=276.4-0.203x (1) for specimens of a 25.4mm hollow diameter, y=212.3-0.163x (2) for specimens of a 50.8 mm hollow diameter, al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 216 y=149.7-0.135x (3) for specimens of a 76.2 mm hollow diameter, y=112.9-0.094x (4) where; y is a column ultimate strength in kn x is a temperature fire. since the amount of fireaffected concrete diminished with enlarging the hollow size, the reduction rate of column strength with temperature minimized while the hollow diameter maximized as illustrated in equations (1) to (4).the reduction rate was 20.3% for solid specimens, and 16.3%, 13.5%, and 9.4% for hollow specimens of diameter 25.4mm, 50.8mm, and 76.2mm, respectively. the failure loads of all four specimens subjected to a same temperature were compared together to evaluate the influence of a hollow size as shown in figure (9). it can be seen that the column ultimate load decreased rapidly as the hollow diameter increased up to (50.8 mm). then the reduction rate became slow, especially for specimens exposed to temperature higher than 300 o c. the drops in the failure load for 25.4, 50.8, and 76.2 mm hollow columns compared to the corresponding solid columns were: 23.64%, 45.45%, and 60.00% for unexposed columns, 21.86%, 48.84%, and 58.14% for 300 o c fire-exposed columns, 27.78%, 55.56%, and 63.89%) columns burnt at 500 o c, and 25.38%, 56.15%, and 65.38% for columns exposed to 700 o c, respectively. 4.3. load-axial displacement response the curves, representing the relationships between applied load and vertical displacement, were plotted in figure (10) for solid specimens and in figures (11) through (13) for specimens having a hollow diameter of 25.4, 50.8, and 76.2mm, respectively. from these figures, it can be observed that the columns’ axial displacement, at the same load, increased as the temperature fire raised. because the column’s axial stiffness dropped when they exposed to fire due to the loss in both the column’s effective cross-sectional area and a concrete modulus of elasticity (kodur, 2014). in general, the load-axial deformation responses of 300 o c fire-exposed columns were very close to those of similar unexposed columns at loads smaller than 175, 100, and 75 kn for solid, 25.4mm hollow, and 50.8-76.2 mm hollow specimens, respectively. since the severe fire effect, on structural elements, takes place after exceeding 300 o c. moreover, this rapprochement becomes clearer for largest hollow specimens because of a reduction in the quantity of fire-affected concrete. finally, the presence of pvc pipes, inserted along the column samples, caused a considerable reduction in the column’s axial stiffness due to minimizing the column’s cross-sectional area. figures (14) through (17) show load-vertical displacement curves for samples subjected to the same temperature: 0, 300, 500, and 700 o c, respectively. it is obvious from these figures that the axial al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 217 displacement of columns, subject to an identical load, increased with enlarging the hollow size, especially for columns having a hollow size greater than 25. 4mm. 5. conclusions the main conclusions of the current experimental program are listed as following; 1. the fire-exposed columns displayed tiny cracks after the burning processes. these cracks distributed in a random configuration around the column’s surfaces; their number and depth increased with elevating the temperature. 2. all column specimens experienced a compression failure, where a concrete crushing appeared at their outer-thirds. 3. for identical columns, the axial load capacity reduced as the temperature fire raised to 300-700 o c. the corresponding reductions were: 21.82% -52.73 % for solid columns, 20.00% -53.81% for 25.4mm hollow columns, 26.67% -62.00% for specimens with 50.8mm hollow size, and 18.18% 59.09% for 76.2 mm hollow columns, respectively. 4. the variation of columns’ strength with temperature is nearly linear. furthermore, the reduction rate of columns’ strength with temperature dropped as the hollow size maximized. the reduction rate was 20.3% for solid specimens, and 16.3%, 13.5%, and 9.4% for hollow specimens of diameter 25.4mm, 50.8mm, and 76.2mm, respectively. 5. for same temperature, the column’s strength decreased with maximizing the hollow size. in the unburnt columns, the drop in the column capacity increased to 60.00% when the hollow size augmented to 76.2mm. the strength decline of 76.2mm hollow columns exposed to 300, 500, and 700 o c were 58.14%, 63.89%, and 65.38%, compared to the corresponding solid columns, respectively. 6. the columns’ axial stiffness descended as the temperature fire and the hollow size increased, especially for columns having a hollow size greater than 25.4 mm and burnt at temperature exceeding 300 o c. 6. references [1] bikhiet, m.m., el-shafey, n.f., and el-hashimy, h.m, 2014, "behavior of reinforced concrete short columns exposed to fire", alexandria engineering journal, vol.53, no.3, pp.643653. [2] echevarria a., zaghi a.e, christenson, r., and plank, r., 2015, "residual axial capacity comparison of cfft and rc bridge columns after fire" polymers journal, vol.7, no. 5, may, pp. 876-895. [3] el-shaer, m.a., 2014, "structural analysis for concrete columns subjected to temperature", acta tehnica corviniesis –bulletin of engineering, vol. iv, no.2, april-june, pp. 69-81. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 218 [4] izzat, f.a., 2012, "effect of fire flame (high temperature) on the behavior of axially loaded reinforced scc short columns" journal of engineering, vol.18, no.8, august, pp.889-904. [5] kdhum, m.m., 2013, "effect of burning on load carrying capacity of reinforced concrete columns", journal of babylon university/engineering sciences, vol.21, no.4, pp.1194-1212. [6] kim, t.h., seong, d.j., and shin, h.m., 2012, "seismic performance assessment of hollow reinforced concrete and prestressed concrete bridge columns" international journal of concrete structures and materials, vol.6, no. 3, may, pp. 165-176. [7] kodur, v.r.k., "properties of concrete at elevated temperatures", isrn civil engineering, vol.2014, 2014, pp.1-15. [8] kodur, v.r.k., bisby, l.a., green, m.f., and chowdhury, e., 2005, "fire endurance experiments on frp-strengthened reinforced concrete columns", national research council of canada, institute for research in construction, research report no.185, march, 41pp. [9] sakai, k., and sheikh, s.a., 1989, "what do we know about confinement in reinforced concrete columns", aci structural journal, vol.86, no.2, mach-april, pp.192-207. table (1): details of test specimens. group no. column designation hollow diameter(mm) temperature o c concrete compressive strength (mpa) 1 c0-0 0.0 25 31.5 c0-3 300 c0-5 500 c0-7 700 2 c1-0 25.4 25 32.2 c1-3 300 c1-5 500 c1-7 700 3 c2-0 50.8 25 33.6 c2-3 300 c2-5 500 c2-7 700 4 c3-0 76.2 25 31.1 c3-3 300 c3-5 500 c3-7 700 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 219 table (2): specimens’ collapse loads. group no. column designation temperature o c collapse load (kn) % decrease in collapse load 1 c0-0 25 275 reference c0-3 300 215 21.82 c0-5 500 180 34.55 c0-7 700 130 52.73 2 c1-0 25 210 reference c1-3 300 168 20.00 c1-5 500 130 38.10 c1-7 700 97 53.81 3 c2-0 25 150 reference c2-3 300 110 26.67 c2-5 500 80 46.67 c2-7 700 57 62.00 4 c3-0 25 110 reference c3-3 300 90 18.18 c3-5 500 65 40.91 c3-7 700 45 59.09 figure (1): details of column specimens. (a) specimens dimensions (b) solid columns (c) hollow columns (diameter=25.4mm) (d) hollow columns (diameter=50.8mm) (e) hollow columns (diameter=76.2mm) all dimensions in mm. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 220 (a) positioning the pvc pipe at the reinforcement cage center (b) preparing the reinforcement cage figure (2): details of reinforcement for column samples. figure (4): typical of fire cracks distributed randomly over the specimen surface. figure (3): gradually cooling of specimens. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 221 column specimen figure (5): sample being tested. dial gauge fixed part moveable part, moves upward to apply the load (a) column c1-0 (b) column c2-0 figure (6): crack patterns for unexposed specimens. (c) column c3-0 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 0 50 100 150 200 250 300 0 200 400 600 800 1000 l o a d ( k n ) temperature (ᵒc) solid 25.4 hollow 50.8 hollow 76.2 hollow 0 50 100 150 200 250 300 0 20 40 60 80 100 l o a d ( k n ) hollow size (mm) 0ᵒc 300 ᵒc 500 ᵒc 700 ᵒc figure (8): column’s strength versus temperature. figure (9): column’s strength versus hollow size. (a) column c1-7 (b) column c2-7 figure (7): crack patterns for specimens exposed to 700 o c. (c) column c3-7 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 223 figure (10): load-axial displacement for solid specimens 0 50 100 150 200 250 300 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c0-0 c0-3 c0-5 c0-7 0 50 100 150 200 250 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c1-0 c1-3 c1-5 c1-7 figure (11): load-axial displacement for 25.4 mm hollow specimens 0 25 50 75 100 125 150 175 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c2-0 c2-3 c2-5 c2-7 0 25 50 75 100 125 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c3-0 c3-3 c3-5 c3-7 figure (12): load-axial displacement for 50.8 mm hollow specimens figure (13): load-axial displacement for 76.2 mm hollow specimens al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 224 0 25 50 75 100 125 150 175 200 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c0-5 c1-5 c2-5 c3-5 figure (16): load-axial displacement specimens exposed to 500 o c 0 25 50 75 100 125 150 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c0-7 c1-7 c2-7 c3-7 figure (17): load-axial displacement specimens exposed to 700 o c 0 50 100 150 200 250 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c0-3 c1-3 c2-3 c3-3 0 50 100 150 200 250 300 0 2 4 6 8 10 l o a d ( k n ) axial dis place ment (mm) c0-0 c1-0 c2-0 c3-0 figure (14): load-axial displacement unexposed specimens figure (15): load-axial displacement specimens exposed to 300 o c article al-qadisiyah journal for engineering sciences 13 (2020) 246–252 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: zzahraahadi1992@gmail.com (zahraa hadi marzoq) https://doi.org/10.30772/qjes.v13i4.670 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. mechanical properties of reactive powder concrete: a comparison study zahraa hadi marzoq a*, tumadhir merawi borhan a a department of civil engineering, university of al-qadisiyah, iraq. a r t i c l e i n f o article history: received 28 july 2020 received in revised form 30 august 2020 accepted 15 september 2020 keywords: reactive powder concrete; mechanical properties; compressive strength; splitting tensile strength; flexural strength. a b s t r a c t reactive powder concrete (rpc) is one of the new and most important concrete manufacturing advancements. a significant number of researchers have studied the mechanical properties of such type of concrete and the effect of different parameters on it. some of these researchers presented questions to predict the properties of reactive powder concrete depends on its components and the method of curing. this research presents an experimental investigation on the mechanical properties of rpc such as compressive strength, splitting tensile strength and flexural strength. the findings were compared to the previous studies’ experimental work and formulated equations. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction reactive powder concrete (rpc) has gained tremendous attention in the world in recent years due to its superior mechanical properties such as high strength, high durability, high ductility, high abrasion and corrosion resistance and minimal shrinkage [1, 2]. the first output of rpc goes to [1, 2] when they published their first researches about rpc in 1994 and 1995 respectively. according to the superior structural performance, rpc is often known as uhpc (ultra-high-performance concrete). it consists of a large quantity of cement (800-1000 kg/m3), silica fume, sand finer than 600 μm particle size or crushed quartz, fibres, superplasticizers, w/c ratio is mostly less than 0.2, with the nonexistence of coarse aggregate richard et al. [2]. after that, numerous numbers of researchers have followed their recommendations and attempt to explore and improve the mechanical properties of such concrete. roux et. al. [3] studied rpcʹs durability. biolzi et. al. [4] investigated the influence of micro steel fibres on compressive strength, direct tensile strength and the elastic modulus of rpc. ograss et al. [5] studied the effect of short steel fibres and a combination of short and long fibres on the characteristics of uhpc especially that related to the ductility and the size impact. chan et al. [6] investigated the influence of silica fume on the characteristics of steel fibres in rpc, involving pull-out energy, bond strength. gao et al. [7] investigated the effect of dynamic loads on the characteristics of plain and fibres reinforced rpc. fujikake et. al. [8] explored the influence of strain rate on the tensile behaviour of rpc samples when direct tension is applied. tai et al. [9] investigated the response of rpc to uniaxial compression at different loading rates. maroliya et al. [10] presented research to explore the effect of the type of superplasticizers on workability and compressive strength of rpc. yu et. al. [11] studied the properties and mix design of ultra-high performance fibre reinforced concrete (uhpfrc). tam et. al. [12] studied the fresh concrete properties of rpc to gain the optimal conditions for outputting reactive powder concrete utilizing local materials. many of these studies have formulated equations to predict the properties of rpc based on experimental results considering different http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ zahraa hadi marzoq , tumadhir merawi borhan /al-qadisiyah journal for engineering sciences 13 (2020) 246–252 247 parameters, as mentioned before, such as the variability of its ingredients, and the curing regime. this research aims to determine the mechanical characteristics of rpc, cured in water, involving compressive strength, flexural strength (rupture modulus) and splitting tensile strength. the findings were compared to the previous studies’ experimental work and formulated equations. 2. experimental work the experimental work consists of pouring and testing the control specimens (cylinder, cubes, prisms) and study the mechanical properties of kind of concrete such as compressive strength, splitting tensile strength and flexural tensile strength (modulus of rupture). 2.1 material utilized astm c150-type i [13] ordinary portland cement was utilized in this study. the very fine sand, with a maximum size of (600μm), was provided and employed by sieving natural sand having fineness modulus of (2.63) and a specific gravity of 2.64. a grey densified silica fume follows the requirements of astm c1240-04 [14], was used. superplasticizer, commercially known as flocrete pc 200, was utilized following the requirements of astm c494 m-99 [15] type g. straight micro steel fibres with a length of 13 mm and a diameter of 0.2 mm were utilized (aspect ratio of 65). the tensile strength of this type of fibre is 2500 mpa and it conforms the requirements of astm a820-04 [16]. 2.2 patching and mixing procedure the mix proportions are based on mixes from previous studies to achieve compressive strength greater than 100 mpa in water curing condition [17, 18]. the cement to sand ratio was 1:1 where the cement weight is (1000 kg/m3). the superplasticizer dosage was chosen as 6% by the weight of cementitious materials (cm)) as recommended by the manufacturing company. the steel fibres ratio was 2% by total volume while the silica fume content was 25% by weight of cement. the w/cm ratio of the mix was (0.2). the mixtures were produced through a horizontal rotary mixer. for three minutes, the dry materials were mixed first. then 2/3 of the liquid (water and superplasticizer) was added, and the ingredients were combined for four minutes. the mixer was interrupted to shovel the mix, then resumed for another three minutes. the process was repeated until the homogeneous mix was achieved. as mixing was integrated, steel fibres were added by hand. the remaining liquid was added. the mixing process required 25-30 minutes approximate time. 2.3 casting and curing the samples of prisms, cylinders, and cubes were poured into the moulds and then covered with a polyethene sheet for 24 hours to prevent loss of moisture. after 24 hours, the specimens were extracted from the moulds, labelled and then placed in water until the age of 28. 3. results and discussions 3.1 compressive strength (f ʹc): this test was performed according to bs en 122390 -03[19] using cube samples with dimensions of 150x150x150 mm and astm c39-05 [20] using cylinder samples with a diameter of 100 mm and a length of 200 mm. figure 1 compression failure of rpc cylinders and cubes. the outputs of this test are shown in error! reference source not found. error! reference source not found. demonstrates the ductile failure of rpc cubes and cylinders. the ratio of cube compressive strength to cylinder compressive strength (fcu / f 'c) is (1.018). this ratio is lower than that stated by neville [21] for conventional concrete which was 1.25. graybeal et al. [22] addressed that the (fcu / f 'c) ratio is in the range of (1.0 1.075) for uhpfrc. the experimental results for qasim [23] revealed that the relationship between f'c (cylinder 100x200)/fcu (cube 100x100) is equal to 0.95 which is very close to that of ma et. al. [24] who found that f'c (cylinder 100x200)/ fcu (cube 100x100) for uhpc is equal to 0.98. also, ma'roof [25] found that this ratio is ranged from 0.9 to 0.979 for rpc. notations bf the bond factor that accounts for bond characteristics of the fibers mm melemeter df fibre diameter in mm w/cm f fiber factor mpa mega pascal (n/𝑚𝑚2) fc cylinder compressive strength abbreviations fsp splitting tensile strength aci american concrete institute fcu cube compressive strength astm american society for testing and material lf fibre length in mm hsc high strength concrete fr modulus of rupture rpc reactive powder concrete riv fibre reinforcing index uhpc ultra-high performance concrete vf fibre volume fraction uhpfrc ultra-high performance fiber reinforced concrete 248 zahraa hadi marzoq , tumadhir merawi borhan /al-qadisiyah journal for engineering sciences 13 (2020) 246–252 table 1 mechanical properties of concrete utilized in this study f 'c (mpa) fcu (mpa) fsp (mpa) fr (mpa) 111 113 13.33 15.29 where: f 'c is cylinder compressive strength, fcu is cube compressive strength, fsp is splitting tensile strength, fr is the modulus of rupture the higher powder content and the smaller maximum aggregate size of rpc can explain the closeness in the values of compressive strength for both specimen shapes ma et al. [26]. the absence of the coarse aggregate and the existence of finer sand in the ingredients of rpc result in denser concrete and then higher strength compared to conventional concrete. the improvement in compressive strength for rpc can also be explained due to the influence of the high-performance superplasticizer (pc200) which reduces the (w/cm) ratio utilized in rpc mix. in addition to the chemical reaction of the silica fume with the calcium hydroxide ca(oh)2, generated from cement hydration, which increases the compressive strength, decreases the microcracking and the voids and strengthen the microstructure. the existence of steel fibre results in a substantial increase in compressive strength. fig. 1 displays the steel fibre holds the specimen as one unit without separating its sections. these results were approved by a significant number of researchers [17, 18, 25]. the influence of steel fibres on compressive strength was also noticed by others like ismail et al. [18] who found that when the steel fibre content is increased from 0% to 1% and 2% followed by an increase in compressive strength by about 22.71% and 35.05% respectively. in the case of silica fume, the results revealed that this type of materials is less effective than using fibre where increasing the ratio of silica fume from 15% to 20% and 25 % increases the compressive strength (fc) of rpc by 5.35% and 9.29% respectively. hannawayya et al. [17] concluded that utilizing higher steel fibre ratio by 2% increases the compressive strength by about 38.06% while an insignificant change in the compressive strength (fc) was obtained for low values of vf. also, increasing silica fume up to 15% increases the compressive strength by about 16.136%. ma'roof [25] showed that increasing the steel fibre ratio from (0% 2%) improves the strength in compression by about 26.42%. the silica fume content exhibits moderate influence on the compressive strength of rpc, where increasing the silica fume from (15% 25%) of the weight of cement raises the compressive strength by about 16.47%. 3.2 splitting tensile strength (fsp): in this study, the test was performed on standard concrete cylinders with dimensions of (100 * 200 mm). the outcomes of this test are reported in table 1. fig. 2 displays the splitting failure of rpc cylinders. it was revealed that the splitting tensile strength to the cylinder compressive strength ratio (fsp / f ′c) was about 12%. danha [27] noticed that this ratio for the non-fibrous rpc mix is 4.65% and ranged from 7.26 to 14.24% for rpc mixes with (1-3%) volume fraction of steel fibres. such performance is close to that achieved by other researchers such as hannawayya [17] who found that the ratio of (fsp/f ′c) ranged from 6.92% to 14.18% for rpc mixes with (0%-2%) steel fibres' volume fraction. graybeal [22] also established that this ratio is ranged from 13.1% to 15.7% for uhpc with 2% steel fibres volume fraction. many studies proposed a relation between (fc) and (fsp) strengths for normal and high strength concrete: figure 2 splitting failure of rpc the aci 318-11 [28] adopted the following relationship for estimating the splitting tensile strength (fsp) from compressive strength (f ′c) for normal and lightweight concrete: 𝑓𝑠𝑝 = 0.56 √𝑓𝑐 (1) carino and lew [29] revised the above relationship and proposed the following in place of the aci code relationship: "𝑓𝑠𝑝 = 0.272 ∗ 𝑓𝑐0.71" (2) arigolu et. al. [30] suggested the equation below after a large-scale regression analysis for concrete including silica fume or fly ash with compressive strengths ranging from 48 to 120 mpa. "𝑓𝑠𝑝 = 0.387 𝑓𝑐0.64" (3) for hsc, vogel et al [31] proposed utilizing the aci 318 equation with the factor of 0.593 instead of 0.56, stated in equation 1, as follows: "𝑓𝑠𝑝 = 0.593 ∗ √𝑓𝑐 (4) for fibre reinforced concrete, thomas and ramaswamy [32] proposed using the following relation to calculate the splitting tensile strength ׃ "𝑓𝑠𝑝 = 0.63 ∗ (𝑓𝑐𝑢0.5) + 0.288 ∗ (𝑓𝑐𝑢0.5) ∗ 𝑅𝐼𝑣 + 0.052 ∗ 𝑅𝐼𝑣 (5) zahraa hadi marzoq , tumadhir merawi borhan /al-qadisiyah journal for engineering sciences 13 (2020) 246–252 249 where: riv: is fibre reinforcing index determined from the equation below: "𝑅𝐼𝑣 = 𝑉𝑓 ∗ 𝐿𝑓 /𝐷𝑓 " (6) where: vf, lf, df are fibre length in mm, fibre diameter in mm and fibre volume fraction respectively. some local researchers attempted to find an empirical relation to predict the splitting tensile strength for rpc, the following equations are some examples: al-ne’aime [33] performed a regression analysis to establish several empirical linear relations between the compressive and the splitting tensile strengths of rpc and modified reactive powder concrete mrpc with different cases as follows: 1-for original rpc at 20 c°, the relation may be given as below: "𝑓𝑠𝑝 = 0.0643 ∗ 𝑓𝑐 + 6.428" (7) 2for modified rpc at 20 c°, the relation may be given as below: "𝑓𝑠𝑝 = 0.2104 ∗ 𝑓𝑐 − 12.537" (8) 3for original rpc and mrpc at 20 c°, the relation may be given by the below linear equation: "𝑓𝑠𝑝 = 0.1372 ∗ 𝑓𝑐 − 0.734" (9) hannawayya [17] performed a regression analysis to establish an empirical equation. this relation can be utilized to calculate splitting tensile strength of rpc with cylindrical compressive strength varying from 79 mpa to 119 mpa and has steel fibre ratios between 0% to 2%. the following simple form was introduced: "𝑓𝑠𝑝 = 22.744 − 1303.74 𝑓𝑐 + 2.028 ∗ 𝑣𝑓" (10) also, mahdi [34] gave a 4th-order polynomial equation comparing compressive strength to splitting tensile strength for the situations of selfcompacting plain rpc as well as with 2% volumetric ratio of steel fibre. the relationship’s general form is reported as follows: "𝒇𝒔𝒑 = 𝒂(𝒇𝒄𝟑) + 𝒃(𝒇𝒄𝟐) + 𝒄(𝒇𝒄) + 𝒅" (11) where: 𝑎, 𝑏, 𝑐 and d: are constants and their values are shown in table 2. table 2 constants adopted by mahdi [34] constant mix without fibres mix with fibres a -1.0651x10-4 3.369469x10-4 b 0.0234 -9.678x10-2 c -2.15565 12.22517 d 75.1165 -549.83067 ridha [35] established a relationship for splitting tensile and compressive strengths of rpc for non-fibrous rpc (f'c) and for the steel fibres’ volume fraction (vf), according to the test results of their study and other investigators. the suggested expression may be written in the following form: "𝑓𝑠𝑝 = 0.37 ∗ (𝑓𝑐𝑓0.8) ∗ 𝐹0.2" (12) "𝑓𝑠𝑝 = 0.94 ∗ (𝑓𝑐0.5) + 3.5 ∗ 𝑣𝑓" (13) ma'roof [25] proposed an expression for predicting splitting tensile strength of rpc with compressive strength ranged from 78 to 161 mpa which is: "𝑓𝑠𝑝 = 25.72 − 1581.7 𝑓𝑐 + 5.835 ∗ 𝐹" (14) "𝐹 = (𝐿𝑓/𝐷𝑓) ∗ 𝑣𝑓 ∗ 𝐵𝑓" (15) a comparison between previous equations is listed in table 3 and fig. 3. it can be spotted that in estimating splitting tensile strength of figure 1 experimental and determined tensile splitting strength rpc, equation 7 has a better agreement with experimental results than other equations. figure 2 experimental and determined tensile splitting strength table 3 experimental and determined tensile splitting strength authors’ results a ri g o lu e t. a l. [ 3 0 ] v o g e l e t. a l. [ 3 1 ] t h o m a s a n d r a m a sw a m y [3 2 ] a ln e ’a im e [3 3 ] r id h a 1 [ 3 5 ] h a n n a -w a y y a [ 1 7 ] m a 'r o o f [2 5 ] fc fsp 111 13.33 7.88 6.25 10.74 13.56 14.69 15.05 15.26 3.3 flexural tensile strength (fr): in this test, the flexural load was applied, by two-point loading, on prisms specimens, with dimensions of 100x100x500 mm, to obtain indirect tensile strength of concrete. table 1 records the results of the modulus of rupture for concrete utilized in this research. each value reflecting the average of three prisms. the ratio of the flexural strength to cylinder compressive strength (fr /f ′c) for rpc in the present study is 13.77%. danha [27] established that this ratio is 6.78% for the non-fibrous rpc mix and ranged from 10.42% to 19.28 for rpc mixes with (1%-3%) volumetric ratio of steel fibres. this ratio is so close to that obtained by other researchers such as hannawayya [17] who found that it ranged from 6.3% to 17.33% for rpc mix with steel 0 2 4 6 8 10 12 14 16 18 250 zahraa hadi marzoq , tumadhir merawi borhan /al-qadisiyah journal for engineering sciences 13 (2020) 246–252 fibres volume fraction of (0%-2%). as well as, graybeal [22] found that the ratio ranged between 14.02% to 25.04% for uhpc with 2% steel fibres volume fraction. it is worthwhile to notice that the fibrous concrete mix is significantly higher in the modulus of rupture relative to the conventional concrete. this increase is due to the increment in the bonding strength between the fibres and the matrix and increasing the ductility of such material. also, the increase in flexural strength can be attributed to the pozzolanic reaction with ca(oh)2 crystals located in the transition zone and as a result developing the bond between the cement particles and the aggregate surface. many studies were conducted to predict a correlation concerning the concrete’s compressive strength and its modulus of rupture. aci 318m-11 [28] adopted the following equation for plain concrete to introduce the connection between flexural strength and compressive strength: "𝑓𝑟 = 0.62 √𝑓𝑐 " (16) the above relationship excludes the influence of steel fibres ratio. since the steel fibres have a substantial effect on compressive strength and modulus of rupture, an empirical linear relationship between the flexural strength of the rpc and its compressive strength for rpc mix cured at 20c° was proposed by al-wahili [36] who performed a regression analysis for this purpose. the measured correlation coefficient was 0.930. the relation can be described by the below linear expression: "𝑓𝑟 = 0.184 𝑓𝑐 − 4.955" (17) ali et. al. [37] suggested a relation between compressive strength and modulus of rupture for rpc as follows: "𝑓𝑟 = 0.03 ∗ 𝑓𝑐1.3 ∗ (𝐹0.004)" (18) kasser [38] performed a regression analysis to establish an empirical relation between compressive strength and modulus of rupture for all types of rp-scc and fr-rpscc (plain and steel fibre reinforced sc-rpc). these relationships can be implemented by the following linear equations: "𝑓𝑟 = 0.0462 ∗ 𝑓𝑐 + 4.2501" for plain rpc (19) "𝑓𝑟 = 0.0901 ∗ 𝑓𝑐 + 9.4383" for rpc with steel fibre (20) to determine the flexural strength for fibre reinforced concrete, thomas and ramaswamy [32] proposed the below equation: "𝑓𝑟 = 0.97 ∗ (𝑓𝑐𝑢)0.5 + 0.295 ∗ (𝑓𝑐𝑢)0.5𝑅𝐼𝑣 + 1.117 ∗ 𝑅𝐼𝑣" (21) where: 𝑓cu: cube compressive strength for non-fibrous concrete (mpa) and riv: fibre reinforcing index calculated from equation (6). hannawayya [17] suggested an empirical relationship for steel fibre reinforced rpc according to the results of his experimental study: "𝑓𝑟 = 332.848 𝑓𝑐 + 7.532 ∗ 𝑣𝑓" (22) mahdi [34] suggested two expressions for sc-rpc, one for plain and the other for steel fibre reinforced rpc which are respectively: "𝑓𝑟 = 44.7537/(1 − 0.4979 ∗ 𝑓𝑐)" (23) "𝑓𝑟 = 44.7537 − 0.4949 ∗ 𝑓𝑐 + 3.1808 ∗ 10−2(𝑓𝑐1.5)" (24) ridha [35] established the flexural tensile strength (frf) in terms of the compressive strength of non-fibrous rpc (fc) and with the volume fraction of steel fibre (vf), according to the test results of her study and other studies. the suggested equation can be written in the form below: "𝑓𝑟𝑓 = 2.8 ∗ (𝑓𝑐 ∗ 𝐹)0.44" (25) "𝑓𝑟𝑓 = 0.056 ∗ 𝑓𝑐 + 6 ∗ 𝑣𝑓" (26) ismail [18] proposed an expression to calculate the relation between compressive strength and modulus of rupture for rpc as shown below: "𝑓𝑟 = 668.475 𝑓𝑐 + 6.486 ∗ 𝑣𝑓" (27) a comparison between previous equations is listed in table 4, fig. 4. it can be observed that equation 21 has a promising result compared to the experimental findings than other equations in estimating rpc’s modulus of rupture. figure 4 experimental and determining modulus of rapture for rpc table 4 experimental and determining modulus of rapture authors’ results a l w a h il i [ 3 6 ] m a h d i [ 3 4 ] a li e t. a l. [3 7 ] t h o m a s a n d r a m a sw a m y [ 3 2 ] . k a ss e r [3 8 ] r id h a 1 [ 3 5 ] h a n n a w a y y a [ 1 7 ] is m a il [1 8 ] fc fr 111 15.29 25.34 27.02 13.9 15.84 19.44 18.39 18.06 18.99 4. conclusions  it is possible to gain rpc with compressive strength of 111 mpa, modulus of rupture of 15.29 mpa and splitting tensile strength of 13.326 0 5 10 15 20 25 30 zahraa hadi marzoq , tumadhir merawi borhan /al-qadisiyah journal for engineering sciences 13 (2020) 246–252 251 mpa at room temperature utilizing normal water curing instead of heat curing to save the cost with mix propotion of 1000 kg/m3 of cement, 1000 kg/m3 of sand, silica fume =25% by wt. of cement, steel fiber = 2% of mix volume, w/cm = 0.2 and superpasticeser = 6% by wt. of binder .  in this study, a comparison between the compressive strength that resulted from cube and cylinder specimens showed that the shape of the specimens has limited influence on the rpc’s compressive strength. the result revealed that the ratio of the cylinder to the cube compressive strength is 0.98.  for splitting tensile strength, the results showed that the equation which proposed by al-ne’aime has a better agreement with the experimental results than other equations.  for flexural tensile strength, the results showed that the equation which proposed by thomas and ramaswamy has a better agreement with the experimental results than other equations. references [1] richard, p. and cherezy, m., "reactive powder concrete with high ductility and 200-800 mpa compressive strength". aci sp144-24, 1994: p. pp. 507-518. 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( 2007), university of technology: baghdad. p. 132. article al-qadisiyah journal for engineering sciences 12 (2019) 079–083 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: entesar_kareem@yahoo.com (entesar kareem) https://doi.org/10.30772/qjes.v12i2.596 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. effect of leachate recirculation on biological stability of municipal solid waste under simi-arid conditions entessar hussaina,b and jathwa al-ameenb* a civil engineering department, university of alqadisiyah, iraq. b environmental engineering department, university of baghdad , iraq. a r t i c l e i n f o article history: received 14 june 2019 received in revised form 26 june 2019 accepted 30 june 2019 keywords: sanitary landfill bioreactor landfill leachate recirculation a b s t r a c t the present study was conducted to monitor the quality of leachate generated from solid waste landfills operated under different mode over a period of 335 days using a bench scale lysimeters. sixty six kg waste sample reflecting the typical municipal solid waste (msw) streams generated in al-diwaniyah city open dump was used to fill both sanitary and bioreactor lysimeters to study the influence of leachate recirculation on quality of leachate in landfills located in semi-arid areas. leachate quality is frequently monitored in terms of ph, electrical conductivity (ec), chemical oxygen demand (cod), chloride, and total kjeldahl nitrogen (tkn). the results show that ph and electrical conductivity values were clearly fluctuated in the rainy season, while in the dry season the values tend to decrease steadily with a close correlation between the chloride and electrical conductivity parameters. the study reveals that bioreactor landfill with leachate recirculation appears to be the most effective option in the removal of organic matter by 98% removal efficiency compared with 58% removal efficiency in a sanitary landfill. the main difference between recirculation and non-recirculation options is determined through leachate quality. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the landfill is one of the oldest and most economical means to dispose of municipal solid waste msws. the area occupies ranges from several acres to hundreds[1]. as many management practices were implemented, recycling and reuse still lead to some waste that must be buried through landfill. however, despite the importance of landfill management, leachate disposal generated from landfills were unsatisfactory [2]. according to nag et al. [3], leachate from landfills represents a potential threat to the ecosystem and surrounding population. the main objective of sanitary landfills is isolating the waste from the environment so that potential risks through a biological, chemical and physical transformation in msws could be eliminated. in general, the degree of isolation required in industrialized countries is more environmentally friendly than in developing countries [4]. the upgrading of existing landfill technologies from storage or containment a in sanitary landfills to a process-based approach is called the “ bioreactor landfill “ [5]. due to the slow degradation of msws in sanitary landfills, bioreactors represent a new concept in solid waste management approach. bioreactors are healthy landfills that promote the microbial degradation and clarify the use of microbial processes to transform and a stabilize the components of biodegradable organic waste in a short period of time by leachate recirculation into the waste body, contrary to sanitary landfill where the leachate drained out [6]. unlike sanitary landfills, bioreactor landfills are designed to maximize water penetration. bioreactor landfills accelerate biodegradation to stability by controlling the moisture content of the waste, recovering food and seed microorganisms through the leachate recirculation system [3]. the recovery of leachate through landfills helps to reduce the strength of organic matter, maintain the moisture content of landfills and reduce toxic substances[7], [8]. infiltration of rainfall through the final cover is rare and short-lived in http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 80 entessar hussaina and jathwa al-ameenb /al-qadisiyah journal for engineering sciences 12 (2019) 079–083 simi-arid region. in a semi-arid environment, 86% to 91% of the rainfall precipitate on landfill cover will be evaporated from these unvegetated landfill covers [9]. thus, under semi-arid climatic conditions, the moisture content in landfills is limited, as a result, the degradation process is slow and limited. leachate generation of landfills in the semi-arid region is influenced by a distinct dry season of up to 270 days a year, high temperatures , high solar radiation, and short period wet season with disappointing rainfall events within a few hours. the practice of recirculation leachate through landfill research was adopted to maintain the moisture content in a landfill, where moisture content is found to be a key factor in degradation process [7], [10] and [11]. landfills in semi-arid climatic areas have not been well studied. the literature contains very limited information on the interaction between a dry climate and the quality of landfill leachate in different operation modes. in general, field investigations of landfills in semi-arid climates should be carried out to gather practical and reliable data, particularly leachate quality and degradation processes. in this work, bench scale lysimeters experiments were designed to obtain primary information about the major environmental concerns involved in msws landfill design for sustainable solid waste management in a semiarid climate, namely the quality of leachate and decomposition processes with a novel strategies in operation sanitary and bioreactor landfills by allowed to the leachate to percolate inside the waste body to amends the lack in moisture content during long dry seasons and assessment of recirculation of leachate in supported the metabolic processes, and enhancement degradation process in bioreactor landfill. in this study, the quality of leachate from sanitary and bioreactor landfill simulators are determined and compared. leachate quality is investigated by measuring ph, electrical conductivity (ec), chemical oxygen demand (cod), chloride (cl-), and total kjeldahl nitrogen (tkn). all analyses were passed through a 0.45 μm membrane filter then tests according to the relevant methods described in the standard methods of apha [12]. the quality parameters of leachate were monitored weekly for 335 days during rainy and dry seasons from december 2017 to october 2018. 2. material and methodology. 2.1. bench scale lysimeter construction two bench scales (bl) lysimeters were installed, the first lysimeter was operated as sanitary landfill (bls), while the second operated as a bioreactor landfill with leachate recirculation (blb).the bench lysimeters were made of high density polyethylene hdpe pipe with 40 cm in diameter and 70 cm in height, sealed from the top and bottom.the multipurpose vent was installed at the top cover in each lysimeter for gas escaping and for rainfall simulation addition or leachate recirculation. the lysimeters were standing on a locally manufacturing a platform stand made of steel, elevated above the ground level about 40 cm, to collect and direct generated leachate to a receiving tank of (20 l), located underneath the platform. a layer of compacted clay was provided at the bottom of each lysimeter to prevent downward movement of leachate followed by a geotextile layer to avoid clogging of drainage pipes holes. gravel layer was applied for leachate filtration and drainage including perforated pvc draining pipe with a 25 mm valve equipped with faucet to drain leachate. a composite cover consisting of, sand and compacted clay respectively were placed over the fresh waste lysimeters to eliminate the emission of distasteful odor in the surrounding area. one layer approximately 50 cm, equivalent to around 530 kg/m3 compacted density in both lysimeters. fig.1. provide a photo and schematic diagram of lysimeters. a b figure 1: a) photo of lysimeters; b) schematic diagram of lysimeters 2.2. filling the lysimeters a synthetic municipal solid waste identical to the composition of msw in al-diwaniyah open dump was prepared to fill the bench scale lysimeter systems according to field survey adopted by [13]. the proposed component was manually shredded to a maximum size of 1 cm and buried in each lysimeter in one layer. the msw deposited in lysimeters consists of 43% organic waste, 7.8%papre, 4.6% plastic, 4.8% metals, 5.6%glass, 5.2% textile, and 29% others wastes, followed by a thin cover layer of sand and clay. 2.3. ambient boundaries and operation simiarid climate in studying area (al-diwaniyah) city consists of the prolonged dry season of 7 months (may to september) and wet season with rare precipitation events within few hours as seen in fig. 2. from the meteorological point of view, the climate of al-diwaniyah can be divided into two seasons as follows: rainy season and dry seasons. the two benchscale landfills were constructed outdoor for allowed to a same actually environmental condition that landfills will expose, one of the bench landfill were operated as sanitary landfill bls, while the other operated as bioreactor landfill with leachate recirculation blb . the leachate recirculation was frequented once a week as the same as sampling frequency. the rain simulation was based on the average daily record; the addition of water was the same as the actual amount of precipitation that infiltrated into the landfill body in the case study. the added water was calculated as: (mean daily rainfall * surface area of the reactor (i.e. 0.125 m2) as the surface area of the lysimeter was 0.125m2 by assuming that all the amount of rainfall percolating through the landfill cover. figure 2: rainfall events during period of the study entessar hussaina and jathwa al-ameenb /al-qadisiyah journal for engineering sciences 12 (2019) 079–083 81 3. results and discussion 3.1. ph the ph in leachate is considered to be the most significant parameter affecting leachate concentration in msw landfills [14]. ph in the viewpoint of [15] was considered as an indicator of the aggressiveness of leachate, where metal dissolution is enhanced at low ph which is one of the characteristics of young landfill leachate [16]. fig. 3. shows the variation of ph in relation to the increasing of the elapsed period in bls and blb landfills. the results show that the initial ph value of blb samples was 7.11, ph values decreased later to 6.33 due to acid accumulation because of organic matter hydrolysis producing organic acids as end products of acidogenesis bacteria metabolism besides the addition of leachate to the lysimeter causes a reduction in volatile fatty acid (vfa) concentration [14]. the lowest ph value in the blb was 6.33 on day 49, ph values increased in blb to 8.49 on day 229 of filling such increasing in ph values indicate the onset of methane production phase concurrent with hydrogen, carbon dioxide and vfa reduction [17]. in bls the initial ph level was 7.26. ph values decreased later to 6.31, ph reduction can be attributed to the same reasons already mentioned above. the lowest ph value in bls was 6.31 on day 65 of filling. ph values increased to 8.33 on day 271. according to [18] in an anaerobic systems ph will be less than 6, with high organic content, long acidogenic phase, high vfa concentration, and insufficient alkalinity producing a potential inhibition to methanogenesis. on the contrary, high ph with low organic content, and sufficient alkalinity methanogenesis commenced. figure 3: ph variation in leachate samples for bls and blb landfills 3.2. electrical conductivity(ec ) electrical conductivity (ec) data were plotted versus days after filling to find out the ability of leachate to carry out electrical current based on the concentration of ions. fig. 4. shows the variation of ec in relation to the increasing of elapsed period bls and blb landfills. in blb, ec concentrations varied between 18 and 27 ms/cm in the first 100 days period followed by a slight reduction in heavily raining days. steadily values were detected in the dry season. in bls the same trend was noticed with values ranging from 15 ms/cm to 17 ms/cm in the first 100 days. ec concentrations were higher in blb lysimeter during an experimental trial due to leachate recirculation. ec values were clearly fluctuated in the rainy season, while in the dry season the values tend to decrease steadily except for later days and that may be due to high evaporation . data were obtained coincide with the researchers [19] and [20]. figure 4: ec variation in leachate samples for bls and blb landfills 3.3. chemical oxygen demand (cod) organic matter released from the landfill lysimeters reflects landfill stabilization indirectly and evaluated by the cod concentration measured values [2]. as the overall strength of leachate measured by cod [21]. fig. 5. shows the variation of cod in relation to the increasing of the elapsed period in (bls and blb)landfills . in blb the results show that the highest cod concentration value was observed on day 65 of the filling, where it reached 47000 mg/l. values began to decrease later on gradually reaching a value of 550 mg/l on day 327 of the experiment. cod results in bls differ from its counterpart in the blb, where results showed that rainfall had effected. cod value increased gradually in the rainy season to reach its maximum value on day 100 reaching a value of 41200 mg/l. values dropped later till the end of the rainy season to reach to the value of 23100 mg/l on day 146 , while in the dry season the cod values increased to reach 35000 mg/l on day 192 then decreased gradually until the end of the experiment to reach 18000 mg/l on day 327. reduction in cod values in both bls and blb is similar but the duration of the drop occurred was much shorter in bioreactor than in sanitary landfill, this finding coincides with [22]. maximum reduction value in cod after 335 days of landfilling was accounted for blb(98%) while the lowest removal was accounted for bls (58%). the enhancement reduction value indicates the efficiency of the recirculation technique for providing in-situ leachate treatment as well as enhancement of degradation of organic matter. figure 5 : cod variation in leachate samples for bls and blb landfills 4 5 6 7 8 9 10 10 35 60 85 110 135 160 185 210 235 260 285 310 335 p h time (days) bls blb rainy season dry season 0 10 20 30 40 50 10 35 60 85 110 135 160 185 210 235 260 285 310 335 e c m s/ cm time (days) bls blb rainy season dry season 0 10000 20000 30000 40000 50000 10 35 60 85 110135160185210235260285310335 c o d c o n c e n tr a ti o n m g /l time (days) bls blb dry seasonrainy season 82 entessar hussaina and jathwa al-ameenb /al-qadisiyah journal for engineering sciences 12 (2019) 079–083 3.4. chloride chloride in leachate is considered to be a very conservative anion that is only attenuated during dilution [14]. fig. 6. shows the variation of chloride concentration in relation to the increasing of the elapsed period in blb and bls landfills. at the beginning of the landfill operation, chloride concentrations were 540 and 560 mg/l for the bls and blb, respectively. there is no considerable change in chloride concentrations of leachate generated from bls and blb simulators in the first 75 days of operation. after that period when the rainy season was onset, the dilution effects were significantly appeared in chloride values in bls landfill, with a little effect on blb landfill. in blb landfill no considerable change was noticed during the dry season and last measurements were 520 mg/l was detected, while the last measurement for chloride in bls was 190 mg/l. compared with conductivity in fig. 4. , there is a close correlation between the two parameters observed at both lysimeters. figure 6 : chloride variation in leachate samples for bls and blb landfills 3.5. total kjeldahl nitrogen (tkn) the tkn is the sum of organic nitrogen (organic-n) and nh4-n [12]. organic-nrepresents come from an organic source like amino acids and urea, while the nh4-n is representative of inorganic matter. the variation in leachate nitrogenous compounds in terms of tkn of entire lysimeters operation are provided in fig. 7. the results reveal that tkn in leachate varied from 965 to 422 and from 820 to 398 mg/l, for the leachate collection system bls and blb, respectively. here, in general, the higher value of tkn was recorded for bls against the other landfill type in the rainy season with fluctuation due to the dilution effect. in blb the values of tkn reduce slowly with regular pattern through the rainy season. in dry season tkn was decreased and then remain almost constant throughout the experiment for both blb and bls. at the end of the experiment, tkn concentration is accumulated because of the absence of biological nitrification-denitrification process in anaerobic condition. 4. conclusion a comparison of the leachate quality from two bench-scale landfill lysimeters, operating under different conditions indicates the following results:  environmental conditions represented by rainfall had significant effects on the performance of the landfill and leachate quality.  leachate quantity reflects the main difference between the recirculated and non-recirculated landfill operations.  electrical conductivity and ph values were clearly fluctuated in rainy season due to dilution effects, while in the dry season the values tend to decrease steadily with a close correlation between the chloride and electrical conductivity parameters.  bioreactor landfill with leachate recirculation appears to be the most effective option in the removal of organic matter than sanitary landfill. figure 7: tkn variation in leachate samples for bls and blb landfills references [1] ling, h. i., leshchinsky, d., mohri, y., and kawabata, t. 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(1996). the impact of leachate recirculation on municipal solid waste landfill operating characteristics. waste management and research, 14(4), pp. 337-346 [20] warith, m. (2002). bioreactor landfills: experimental and field results. waste management, 22(1), pp.7-17. [21] knox, k., and jones, p. h. (1979). complexation characteristics of sanitary landfill leachates. water research, 13(9),pp. 839-846. [22] visvanathan, c., tränkler, j., kuruparan, p., and xiaoning, q. (2003, october). effects of monsoon conditions on generation and composition of landfill leachate–lysimeter experiments with various input and design features. in proceedings of the sardinia, ninth international waste management and landfill symposium. s. margherita di pula, cagliari, italy (pp. 6-10). article al-qadisiyah journal for engineering sciences 13 (2020) 223–231 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: drabdullah_dhayea@mtu.edu.iq (abdullah dhayea assi) https://doi.org/10.30772/qjes.v13i3.659 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. solve the cubic equation in a new method with engineering application abdullah dhayea assi a a institute of technology-baghdad, middle technical university, iraqbaghdad a r t i c l e i n f o article history: received 20 june 2020 received in revised form 10 august 2020 accepted 16 august 2020 keywords: matrix tensor eigen values eigen vectors roots cubic equation principal angle a b s t r a c t up to date the cubic equation or matrix tensor is consisting of nine values such as stress tensor that turns into the cubic equation which has been used for solving classic method. this is to impose an initial root several times to get it when achieves the equation and any other party is zero. then dividing the cubic equation on the equation of the root. after that dividing the cubic equation on the equation of the root and using the classical method to find the rest of the roots. this is a very difficult issue, especially if the roots are secret or large for those who are looking in a difficult field or even for those who are in the examination room. in this research, two equations were reached, one that calculates the angle and the other that calculates the three roots at high accuracy without any significant error rate. by taking advantage of the traditional method, not by imposing a value to get the root of that equation, but by imposing an equation to get the solution equation that gives the value of that root. after imposing that equation, the general equation was derived from which that calculated the three roots directly and without any attempts. the angle that was implicitly derived during the derive of the main equation is calculated by taking advantage of the constants that do not change (invariants) for the matrix tensor (t). © 2020 university of al-qadisiyah. all rights reserved. 1. introduction: the main problem in engineering calculations is to determine the eigen values of the matrix (t), which is called matrix tensor (t)). in general, if the (n * n) are the dimensions of the matrix (t), it has (n) of eigen values and (n) of eigen vectors, and this needs to be done manually. in order to increase the accuracy, the computer usually uses to find out all the solutions required for the matrix (t). in other words, finding all or most of the roots and vectors is not mainly depend on the form of the matrix (t), as much as it depends on what the required solutions are. in particular, the eigen values of the matrix extended (matrix tensor) is calculated to keep (3 * 3), and this matrix, which consists of nine components are inherently transformed into an equation of the third degree, (equation cubic). by obtaining eigenvalues, the roots of the cubic equation became research achievement as well as being mathematically engineered achievement. fifty years ago, as well as the generations that followed mathematicians, physics, and astronomy have tried to solve the cubic equation, but all formulas were raised worse than traditional formula. the first scientist who solved the cubic equation is del ferro (scipione del ferro (1465-1626)) in the early sixteenth century, where he lectured in mathematics and engineering at the university of bologna from 1496 until 1526. he wrote a solution of cubic equation in the manuscript, which passed to his pupil antonio maria fiore (antonio maria fior (florido)). there are no reports of deployment of such a manuscript and was racing to find a solution with niccolo fontana tataaelia (nicol ̀ o fontana tartaglia (1500-1557)) kumar et al. [1], who led to the recent discovery of a way to solve the cubic equation of a certain type. girolamo cardano (1501-1576) was able to convince him http://qu.edu.iq/ mailto:drabdullah_dhayea@mtu.edu.iq https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 224 abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 to dissolve it with a full explanation after the swearing in front of niccolo fontana to keep it a secret. he found a solution for the news published in the newspapers and saw that cardano published free of charge, and this is what he did in ars magna in 1545. however, cardano went further than his predecessors because it is summed up nearly 13 formulae and share it one after the death of niccolo fontana tataaelia. cardano scholar athlete was a physician and astronomer, and he had able to publish this formula in his book 1545 ad. his method required the following karunia et al. [2]: 1.1. cardano formula karunia et al. [2] first, simplify the equation to become standard in the following form: x3 + ax2 + bx +c =0 (1) then get rid of the coefficient of the second division with appropriate compensation p, q, t to become the new form of the equation: 3 0t pt q   (2) where: 27 92 3 32 aba cqand a bp   and appropriate compensation in equation (2), it can be obtained: 3 3 (3 )( ) 0u v uv p u v q      (3) here, cardano supposed a new limit for variables u and v so: 3 0uv p  (4) when this merges in equ. (3) by compensating v we get: 3 6 3 0 27 p u qu   (5) it can be seen that this equation of the sixth grade that can simplify into the second division in u3 and resolved to become directly: 2 3 3 2 4 27 q q p u     (6) based on that, u can be calculated by eqn. 7 as: 2 3 3 2 4 27 q q p u     (7) since t = v + u, t = x + a / 3, and v ==-p / 3u, we find that: 3 3 p a x u u     (8) note that there are 6 roots to calculate the likelihood of u in equ. (7), because the square root of two possibilities holds (+ and -) for three roots. but, the square root does not affect the resulting value of t (however, one should pay any attention to three cases to avoid division by zero): first: if p = q = 0, then u has three real roots. second: if p = 0 and q ≠ 0, the: 30 qvandu  third: if the p ≠ 0 and q = 0 is: 33 p vand p u  in any of the three cases, the roots are: p u pw w u t p uw p uwtvut   3 , 3 ,0 1 1 1 1 where: 2 3 2 1 3 2 1 iew i   this way in this time is more complex than the conventional formula. which are summarized in the following classic method: 1.2. classic method: solving the following cubic equation using the classic method [3,4]: λ3 – 5*λ+ 2 = 0 the solution by using this method requires the imposition of a preliminary investigating of the root of the equation through several attempts: oklet 02)2(582025 1 3   01212 2 25 22 3        2: 42.021,42.221 21 )2(1 )1)(1(4)2( )1(2 )2( 1,2,1 2 4 1 32 2 2               and cba a acbb 2. the theoretical part: equ. (9) below, which form the equivalent of a limited class (n) for any form of multi-limits in (λ) have a (n) of the roots (nλ2, ....... λ, 1λ (not necessarily different ghali et al. [5]. 11 12 1 21 22 2 1 2 n n n n nn a a a a a a a i a a a          (9) where this equation is called a characteristic equation or matrix characteristic. given these roots, there are values for the vertical vector(v) obtained from the following equation: 0a i v  (10) before explaining how to test the property of equ. (10) that lead to equ. (1), equ. (1) can be written as the following: av= λv (11) on the left side of the equation, (a) is a matrix of (n * n) dimensions, and vector (v) is a vector of n-vertical dimensions. the question that arises, of course, is the meaning of product a * v. it is clear that the av is the vector as well. accordingly, matrix (a) can therefore be considered effective or transformational when it affects a v, which produces a new n-dimensional vector. this transformation in the space abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 225 of all n of deportation can be realized more clearly if n = 3. for example, in such a situation, one can imagine a matrix a (3* 3) as affecting the vector three-dimensional v and turns it one way or another into three dimensional vector. in three dimensions, in the three dimensions, such a transformation can be conceived as involving a vector rotation, prolonging the vector or shrink, or possibly both, of the overall situation, where n> 3 we can imagine a rotation or possibly prolong vector or reduced in a vacuum -dimensional n, though the such a perception is not as simple as in the case n = 3. now, many researches on the theory of matrices have been completed in germany, so the word aiken "eigen" means in german " self or true ". therefore, the values of λ and vectors corresponding v became known values of self (eigen values) and (eigen vectors) sequentially, and this term will be used in the same equation (9) to find the values of λ. here are some observations that should be displayed. 2.1. methods of numerical analysis to accelerate the convergence: to illustrate the basic idea of numerical methods to analyse the acceleration of convergence and to find values and eigenvectors. suppose that javier et al. [6]: ( ) ( )i i i a y y (12) the terms of: a is a symmetric matrix that wants to find their roots. )(i y  is the eigenvectors which is characteristic. λi is the characteristic eigenvalues, where i = 1, 2,3 , ............, n. since that is a set of orthogonal bases, then we can use any name and optional vector p as a linear combination of the vector )(i y  , as shown in the following: (1) ( 2) ( ) 1 2 ......... n n p c c c       (13) and multiplying the equation (5) in the symmetric matrix a, we get: (1) (2) ( ) 1 1 2 2 ..... n n n a p c c c         (14) assume that the root λ1 for the largest coefficient is real and that the root: 1   r where: r = 1, 2 ,3, ……….., n because we care about the real root λ1 if we re-formulate the equation (14) as follows for λ1: )15(...... )( 1 )2( 2 1 2)1( 11                        n n n cccpa       and multiplying the equation (6) by a matrix to m times and reformulated as in the equation (7), we get the following form: )16(..... )( 1 )2( 2 2 1 2)1( 11 )(                          m n m mmm cccp       and multiplying the equation (16) in the matrix a, we get the following form: 1 1 1 1 (1) ( 2) ( )2 1 1 2 1 1 ..... (17) m m m m nn n p c c c                                  let suppose that: n   ....... 21 so: 0lim 2 1          m m   if c1 is not equal to zero and that the value of vector elements p relatively large, λ1 can extract value from equations (16) and (17) in the following form: 1 (1)1 1 1 1(1) 1 1 lim mm mmn c ya p ca p                 (18) applying the equation (18) we need to get a polynomial equation, and in the case multiply the vector chosen p in the matrix symmetric. we get a new vector and multiplying this vector in the matrix corresponding a after extracting the greatest value from the values of its elements, which represent λ1 and the division of all elements on these values (λ1). as a result of the multiplying, we get a new vector and make it the same previous steps and repeating this process, we get the serial number of unspecified vectors y, as explains it in the following: 0 1 1 yaayy i ii    (19) in the case of the convergence of the values of the vector elements yi with the values of the vector elements yi +1 e ratio ε = yi / yi +1 in this case we get the value of the desired root (λ1) as the convergence does not depend on the choice of y0. 2.2. repeated roots in the case of different eigenvalues from each other and that the foundations of eigenvectors perpendicular. assume that x is the vector that we got after the k of repetition javier et al. [6]: )20(.......... 1 2 1 2 211 n k n n k vcvcvcx                      we suppose that: 1 k n n n c           (21) so: 1 1 2 2 ................ n n x c v v v      (22) we assume that the vector vi is the (normalized), so: 1 1 1 2 2 2 2 2 2 1 1 2 2 ...... (23) and: ..... (24) n n n t n n a x c v x v c                  also: 2 2 2 1 2 ............ t n c        (25) when repeat k increases, each σi close to zero, and this way we get riley (rayleigh equation), which is:   t t 2.3. shift of origin salas et al. [4]: the problems and difficulties that also appear when using the methods of numerical analysis in some arrays are not getting the convergence required for the values of self-eigen values of the matrix (a). in this case, we need to shift to be sufficient for the values of selfeigen values of the matrix a and the same value selected. let s and subtracting this value from the matrix elements of diagonal and will be represented mathematically as follows:       s s si s                  (26) equation (26) can be written in the following form: bx   (27) where:       sandbsi using this method, the eigenvalues will change while eigenvectors are not changed at all and that the ratio of convergence depends on (λn +1 / λn) and if we apply this method to the new matrix (a-si), the eigenvalues of the new matrix is a (λi-s). in this case, the percentage of 226 abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 convergence depends on: s s   1 2   2.4. convergence method in the case of (λ2= λ1) this method is used to solve the third problem and where real roots equal in value and different in the signal and if we use the previous methods for finding eigenvalues of the matrix a, we do not get the convergence. to illustrate the idea mathematically suppose that the vector )( p y  is a linear combination for two of the eigenvectors corresponding to the real roots, and the mathematical relationship will be as follows gao et al. [8]: 2 2 p p y y   (28) the proportion of convergence is  p i p i yy / 2 , and it will stabilize at a constant value λ, and to get rid of this case, we use the displacement method at the center (shift of origin) and so we get the desired convergence. 3. the derivation of the new method to solve cubic equations. the aim of the research or the basic requirement is to solve the cubic equation by several attempts to get constant roots instead of solving each formula of formulas for each case (use of attempts to obtain the equations of the roots and not on the amounts of roots). the required cubic equation can be solved as follows: 0 23  cbxxx * , 3 3 3 3 if kx ky a let k a x y a y x          compensating in the basic equation above:  2900 327 2 3 0 393 2 279 3 0 33 2 33 3 3 3 333 21 3 32 3 32 2 32 23 2 2 32 23 23                                                                                                 yycyy cyyy y yy cy g yyyyy ocyyy  cc andwhere 5.135.4 27 2 327 2 3 3 3 3 3 2 2 1 2            using the laws of trigonometry, as follows: 3 3 3 3 (30) 3 1 4 cos 3 cos cos 3 cos cos cos 3 4 4 3 1 cos cos cos 3 0 4 4 3 1 cos cos 3 0 4 4 if u u u                            13cos3cos1 3cos5.035.05.060cos60 3cos343cos 4 1 4 3 33       uif uuuu then:       satisfy1240603cos240 satisfy1120603cos120 satisfy1603cos60 13 12 1       if if if this means that the cubic equation that is three roots obtained by three angles (α, 120+α, 240+α) each root of these roots must be at an angle from these angles, which does not mean that the roots repeat the same final value as it may be repeated or not repeated depending on the specificity of the equation or matrix tensor that will become an equation. so: 3 3 1 2 3 3 1 2 3 1 2 2 3 (31) (32) (33) 3 1 3 0 4 4 0 0 0 u u cos y k y k let y v u v u k v u k k k u u v v                 in order to make equations (31) and (33) equal each other, the following conditions must be satisfied: 1 2 2 3 1 2 3 2 2 3 3 2 1 3 1 (1) (2) cos 3 4 4 4 (1) 3 4 (2) cos 3 . (34) . (34) : 4 4 cos 3 (35) 4 3 k k and v v k from v and k from v sub v in equation we get k k v k                         :)(&. 21 getweeequationinkksub  3 3 22 3 3 2 2 2 4 4.5 13.5 27 cos 3 4 3 3 3 8 4.5 13.5 27 (36) 4 3 9 a a b c b a a a b c b a                                      3 2 3 2 3 2 3 2 8 4.5 13.5 27 cos 3 8 3 27 4.5 13.5 cos 3 (37) 3 a a b c b a a a b c b a                            where it was to get rid of the negative after inserted into the equation: abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 227 3 1.5 2 1 2 3 3 3 4.5 13.5 cos (38) 3 , 120 120 3 3 , 240 240 3 let a a b c a b                                        to get the greatest value: 2 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 * cos( ) (39 ) 9 3 * cos( ) (39 ) 9 3 * cos( ) (39 ) 9 a b y at y a a b y at y b a b y at y c                   but what is needed is (x) and not (y) because the general equation is a function of (x) either (y) is a dummy variable or default. 2 1 2 2 2 3 3 3 * cos (40 ) , 9 3 3 3 * cos 120 (40 ) 9 3 3 3 & * cos 240 (40 ) 9 3 3 a x y a b a x a a b a x b a b a x c                                                    240 3 ,120 3 , 3 321              2 1 1 2 2 2 2 3 3 3 * cos (41 ) 9 3 3 * cos (41 ) 9 3 3 & * cos (41 ) 9 3 a b a x a a b a x b a b a x c                               if these equations are applied, the real roots of (x) is not given because the first hypothesis, that has been imposed (3x = 3y + a), based on a fixed proposal and is not real. to find a real constant any (kx = ky + a). it should multiply the amounts in (k). then:   2 3 * * cos (42) 9 3 1, 2 & 3 i i a b a x k where i      or       2 1 1 2 2 2 2 3 3 (43 ) (43 ) (43 ) 3 * * cos 9 3 3 * * cos 9 3 3 * * cos 9 3 a b c a b a x k a b a x k a b a x k             using attempts and experience for all kinds of tensor, k is calculated. and all kinds of problems gave one value of (k) and the truth here is no possibility for error because the three roots should be given the same value of (k) and this ensures the correctness: take unresolved issues ((i.e. the process inversed our solution and the equation wanted)). we have the roots (x1=3, x2=1, x3=2) for the following cubic equation: 3 2 6 11 6 0x x x    this means that (a = 6, b = 11, c = 6) and the equation of the angle θ we calculate the new value:                         5.12 3 1 5.12 3 3 5.135.4 cos 3 5.135.4 cos ba caba ba caba           o ba caba 90 11*36 6*5.1311*6*5.46 cos 3 5.135.4 cos 5.12 3 1 5.12 3 1                           o oo 270240 3 , 150120 3 ,30 3 3 21         2 3 6 )270cos(* 9 11*36 *2 2 3 6 )150cos(* 9 11*36 *1 2 3 6 )30cos(* 9 11*36 *3 2 2 2          kk kk kk           0.5 2 1 1 0.5 2 2 2 0.5 2 3 3 1 2 * 3 * cos( ) (44 ) 3 3 1 2 * 3 * cos (44 ) 3 3 1 2 * 3 * cos (44 ) 3 3 a x a b a a x a b b a x a b c              to prove that the extended matrix transformed into a cubic equation, as well as identifying signals cubic equation: if we assume that our values are established as a tensor, as follows govindan et al. [9]:   11 12 13 21 22 23 31 32 33 (45) t t t t t t t t t t  this matrix can be converted from one format to format arrays equations where the resulting equation of the third degree, which are as follows: λ3 + a λ2 + b λ + c = 0 the constants in this equation can be calculated using the equation feature | t-λi |, namely: 11 12 13 21 22 23 31 32 33 (46) i i i t t t t i t t t t t t          therefore, these constants can be taken the following forms: a = (t11 + t22 + t33) = trace[t] (47a) 228 abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 b = [ t22 * t11 + t33 * t11 + t22 * t33 + t23 * t32 – t32 * t21 – t13 * t31] = σ miner[t] (47b) c = [ t11 * t22 * t33 – t11 * t23 * t32 – t12 * t21 * t33 + t12 * t23 * t31 + t13 * t21 * t32 – t22 * t31 * t13] = det[t] (47ca) the cubic equation can be written by the mathematical formula, i.e. use x as follows:                5.12 3 1 23 3 5.135.4 cos 0 ba caba cbxaxx              0.5 2 1 1 1 0.5 2 2 2 2 1 0.5 2 3 3 3 1 1 2 3 * cos (49 ) 3 3 1 2 3 * cos (49 ) 3 120 1 2 3 * cos (49 ) 3 240 x a b a a where x a b a b where x a b a c where                                          and recognized on naming constants (a, b, c) in the flexibility and plasticity, vibrations and mechanics of fluids letters (i1, i2, i3) as, respectively, and this label came from an invariants, and it means constants that do not change or constants stress that do not change stress invariants. there are certain constants, whatever the label (a, b, c) or (i1, i2, i3) in the case of recycling extended stress on one axes in a certain direction. the values of nine for this period will be changed, but these constants will be the same for the new extended matrix or does not change, hence the label or coding (i1, i2, i3) instead of (a, b, c). thus, samples can be circulated depending on what the user in engineering books for flexibility and plasticity, vibrations and fluid mechanics, as follows: +λ3 – i1 λ 2 + i2 λ – i3 = 0 i1 = σ tii = trace[tii] , i2 = σ miner [tii], i3 = determent [t] 4. comparison between classic and modern methods the first test: solving the cubic equation in two ways (a) the classic method (b) the new method: 2λ3 – λ2-2*λ +1 = 0 a. classic method ok let 01)1(2)1()1)(2( 10122 23 23    the fact that the first hypothesis λ = 1 is not always easy because it comes from several attempts which did not achieve the equation to that we get to try investigating the equation if the assumption that the figure that achieves the equation is (9). here, we need (18) attempts negative and positive until this figure is captured, which achieves the equation and naturally depends on the experience of the professor. 1;5.0;1 1 2 1 12 0)1)(12(012 12 1 122 0)1)(12(012 12 1 122 321 2 2 23 2 2 23                       and b. new method the cubic equation is : 2λ3 – λ2 -2*λ +1 = 0 ( ÷2) then: λ3 – 0.5*λ2 -λ +0.5 = 0  i1 = 0.5, i2 = -1 and i3 = -0.5           5.1 2 2 1 321 3 11 )3( 5.135.4 cos ii iiii            5.12 3 1 ))1(3)5.0(( )5.0(5.13)1)(5.0(5.4)5.0( cos     1.46 3 3.138 3 3.138 3.13875.0cos 86.5 375.4 cos 1 11               1.28624060240 1.1661201.46120 13 12     also and        11)1.46cos(*))1(35.0(*2 3 1 cos*3*2 3 1 5.02 11 5.0 2 2 11   i        11)1.166cos(*))1(35.0(*2 3 1 cos*3*2 3 1 5.02 12 5.0 2 2 12   i        5.01)1.286cos(*))1(35.0(*2 3 1 cos*3*2 3 1 5.02 13 5.0 2 2 13   i where λ1 > λ2 > λ3 then the principal stresses (eigen values ) are : 1;5.0;1 321   abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 229 5. practical applications 5.1. in elasticity if the point (5,3,0) verifies the equation, find the major stresses (eigenvalues) for a stress tensor at this point.               10000 025.0 05.1 = 4 2 3 21 3 21 2 2 2 1 xxx xxxx  when (i1, i2, i3) are the stress invariants at point (5,3,0):   mpaxxx xxxx                           10000 025.20135 0135337.5 10000 025.0 05.1 4 2 3 21 3 21 2 2 2 1  then : i1 = σ[σii] = 457.75, i2 = σ miner [σii] = 24384.375, i3 =det.[σ]= -1139062.5. o ii iiii 0033.53 )3( 5.135.4 cos 05.1139062375.2438475.457 5.1 2 2 1 321 3 11 23              mpaiii mpaiii mpaiii 100cos32 3 1 4202.29cos32 3 1 1702.387cos32 3 1 132 2 13 122 2 12 112 2 11                                     mpampampa 4202.29,100,1702.387 321   where: 321   5.2. in plasticity the values given below for the strains to the point in the three-axis system, to find eigenvalues for strain tensor.   strain            198065 02615.175 655.175261 where:   107843.1det 3.103146)( 198)( 3 2 1      ij ii ijii i mineri tracei    010843.13.103146198 0 723 32 2 1 3     iii o ii iiii 6994.136 )3( 5.135.4 cos 5.1 2 2 1 321 3 11            566.285566.165,5614.456994.136 321   strainiii strainiii strainiii    4.172cos32 3 1 2.315cos32 3 1 5.341cos32 3 1 132 2 13 122 2 12 112 2 11                                  strainstrainstrain  2.315,4.172,5.341 321  where : 321   5.3. in vibrations for the spring-mass system, find the natural frequency of this system:                                      3 2 12 3 2 1 * 3 7 3 8 3 4 3 4 3 8 3 4 3 1 3 2 3 4 x x x k mw x x x                                                       784 484 124 784 484 124 3 * 784 484 124 3 2 3 2 12 3 2 1 t k mw t x x x k mw x x x to facilitate a solution, we can impose : k mw i 3 2  m k w m k w i i i  332  first: calculate the constants: 72,72,19 321  iii the general formula of the cubic equation is: 07272190 23 32 2 1 3   iii using the equation first, second and fourth we get: o ii iiii 43.16 )3( 5.135.4 cos 5.1 2 2 1 321 3 11               48.245,48.125,48.5,43.16 321   3cos32 3 1 68.1cos32 3 1 33.14cos32 3 1 132 2 13 122 2 12 112 2 11                                  iii iii iii    230 abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 sec/34.168.1 sec/00.100.3 sec/457.033.14 33 22 11 rad m kw rad m kw rad m kw       where 321   or 123   5.4. in fluid mechanics: the main stresses (eigenvalues) are found out to the following compounds of stress.   mpa            18016 03627 102736  where: i1 = a = σ[σii] = 18 i2 = b = σminer[σii] = -2125 i3 = c = det[σ] = -32850 o ii iiii 119 )3( 5.135.4 cos 5.1 2 2 1 321 3 11            oooo 66.279,66.159,66.39,119 321   mpaiii mpaiii mpaiii 1511.15cos32 3 1 161.45cos32 3 1 48cos32 3 1 132 2 13 122 2 12 112 2 11                                     where: 321   mpampampa 161.45,1511.15,48 32`1   5.5. in mathematical. to find the general solution of the system follows: 0382,040575  zyx dt dz zy dx dy zyx dt dx this system can be written as an equation differential form of the first rank matrices:                          z y x ummu dt du & 382 140 575 0 the general equation for such a situation is: where (v) is a vector of three dimensions of vertical fixed now we find the constants of cubic equation:   6345][1 iimi ,   11][2 iimmineri ,   6det 3  mi 0 32 2 1 3  iii  → 06116 23   applying the equations first, second and fourth we get: o ii iiii 90 )3( 5.135.4 cos 5.1 2 2 1 321 3 11             90  30 1  , 150 2  ,  270 3     3cos32 3 1 11211  iii    1)cos32( 3 1 12212  iii    2)cos32( 3 1 3 1321  iii  1,2,3 2&1,3 321 321     or since the eigenvectors are: t veu   t eu 3 1 * 1 1 1            , t eu 2 2 * 2 1 1            & t eu * 3 1 2 3            general solution is: ttt ecececucucucu 2 32 3 1332211 2 1 1 3 1 2 1 1 1                                  the general solution can be written as a mathematical formula rather than engineering as follows: ttt ttt ttt ecececz ecececy z y x u ecececx 2 32 3 1 2 32 3 1 2 32 3 1 23 2                6. conclusion 1 the roots of the cubic equation (or matrix extended) is found as follows: new equation for eigen values:           12 2 1 cos32 3 1 iii ii  2 the angle is calculated from the following equation: the principal angle equation:               5.1 2 2 1 321 3 11 3 5.135.4 cos ii iiii  3three angles are identified by which three roots can be determined as follows: the three angles and three roots of equations (λi): λ1 at θ1 = θ/3 λ2 at θ2 = θ/3 + 120 λ3 at θ3 = θ/3 + 240                                  3 1 2 , 2 1 1 , 1 1 1 321 vvv abdullah dhayea assi /al-qadisiyah journal for engineering sciences 13 (2020) 223–231 231                               132 2 13 122 2 12 112 2 11 cos32 3 1 cos32 3 1 cos32 3 1 iii iii iii    4the constants that do not change (invariants) is calculated from the equations below. it can be seen the following things about these constants (i1, i2, i3) as follows: a-these constants are not changing, if not changed, because the roots have been calculated at (λi) at any root of this equation. bnoting that (i1) means the algebraic sum of the elements of the diameter of the matrix [t], i1 = σ tii = trace[tii]. c-noting that (i2) means the algebraic sum (miner) to the diameter only elements of the matrix [t], i2 = σ miner [tii ]. d-noting that (i3) means a specific matrix [t], i3 = det. [ tij ]. references [1] r. kumar and v. kumar, study on the evolution of cubic equation solving. rep opinion 2020;12(4):1-6. doi:10.7537/marsroj120420.01. [2] e. l. karunia, s. p. udjianna , w. i. sapto and g. g. hanni, generating roots of cubic polynomials by cardano's approach on correspondence analysis, heliyon, v.6(6) jun 2020. [3] a. t. tiruneh, a simplified expression for the solution of cubic polynomial equations using function evaluation, arxiv:2002.06976v1 [math.gm] 14 feb 2020. [4] a. h. salas and s. c. trujillo, a new approach for solving the complex cubic-quantic duffing oscillator equation for given arbitrary initial conditions, mathematical problems in engineering, v.398(975) 2020, article id 3985975,18. [5] r. e. ghali, m. a. almahalebi and s. k. kabbaj, general solution and hyperstability results for a cubic radical functional equation related to quadratic mapping, proyecciones ,vol.39(1) feb. 2020, 107-122 . [6] i. c. javier, the numerical problems within analytical methods of solution for cubic equations of state, ingeniería y competitividad, v.14(1) (2012)75 89 . [7] p. shouthiri and s. disne, solution to cubic equation using java programming”, european journal of mathematics and computer science, v. 7 (1), 2020. [8] w. a. gao , h. f. ismael, h. m. ahmad , b. a. hasan and h. m. baskonus, optical soliton solutions of the cubic-quartic nonlinear schrödinger and resonant nonlinear schrödinger equation with the parabolic law, appl. sci. 219(10)2020; doi:10.3390/app10010219. [9] v. govindan,c. park, s. pinelas & s. baskaran, solution of a 3-d cubic functional equation and its stability. aims mathematics, 5(3)2020, 1693-1705. https://doi.org/10.3934/math.2020114. [10] s. r. javier , the midpoints between roots reveal the quartic equation, the american mathematical monthly, 127(3)2020, 258-262, doi:10.1080/00029890.2020.1697589. [11] d. a. abdullah, matlab and engineering applications, third edition, 2019. https://www.ncbi.nlm.nih.gov/pubmed/?term=lestari%20ke%5bauthor%5d&cauthor=true&cauthor_uid=32577543 https://www.ncbi.nlm.nih.gov/pubmed/?term=pasaribu%20us%5bauthor%5d&cauthor=true&cauthor_uid=32577543 https://www.ncbi.nlm.nih.gov/pubmed/?term=indratno%20sw%5bauthor%5d&cauthor=true&cauthor_uid=32577543 https://www.ncbi.nlm.nih.gov/pubmed/?term=garminia%20h%5bauthor%5d&cauthor=true&cauthor_uid=32577543 https://www.ncbi.nlm.nih.gov/pmc/journals/2992/ https://doi.org/10.3934/math.2020114 article al-qadisiyah journalforengineering sciences (2020) 074–079 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ahmedadnan_ahmedadan@yahoo.com(ahmed adnan al-mudhafar) https://doi.org/10.30772/qjes.v13i2.632 2411-7773/©2019 university of al-qadisiyah. all rights reserved. microstrip stopband split ring resonator for microwave microfluidic sensing ahmed adnan al-mudhafar * a, ali a. abduljabar b, and hayder jawad albattat a a department of communication technologies engineering, engineering technical college, university of al-furat al-awsat technical, 31001 najaf, iraq. bdepartment of electrical engineering, college of engineering, university of basrah, 61001 basrah, iraq a r t i c l e i n f o article history: received 17 march 2020 received in revised form 25 april 2020 accepted 27 april 2020 keywords: split ring resonator complex permittivity microfluidic chanel sensitivity a b s t r a c t stopband split ring resonator (ssrr) is presented in this paper for measuring the complex permittivity of liquid with different positions of microfluidic channel operates at a resonant frequency of 1 ghz. the sensor was fabricated and microfluidic channel is located in the gap groove with two different positions of the carrier where the electric field is as large as possible. the sensor has been tested with several solvents to verify its sensitivity where the electric field interacts with the liquid filled in a quartz tube and hence alter the srr behavior. the electromagnetic properties (complex permittivity) of the solvent can be extracted from the shift in the resonant frequency of the resonator due to the perturbation phenomenon. ©2020 university of al-qadisiyah. all rights reserved. 1. introduction dielectric loss and dielectric constant of the materials are both of which are functions of many parameters that are the field’s frequency, temperature, pressure, orientation, mixture, and molecular structure of the material [1]. many methods have been used to measure the material properties among these resonator resonant techniques offer numerous advantage compared to traditional methods resulting inaccurate measuring of material characterization to get maximum sensitivity the sample inserted posited in a place where the electric field is as large as a possible result shift resonant frequency and peak attenuation due to perturbation of sensor[2, 3]. in recent years, researchers have placed liquid under test in a region where the electric field is the greatest possible. some of them have put the tube in contact with the upper surface of the sensor, inserted the tube inside substrate of the microstrip sensor, placed the tube non-contact with the sensor, and some of them have put the capillary between the substrate and ground plate of the sensor [4-9]. all of them are looking for a more sensitive and accurate measurement of complex permittivity of material /liquids for many applications is required in medicine and pharmaceuticals, surface crack, food industry, and chemical. in this study, design and fabrication of the stopband microstrip split ring resonator is proposed as a microfluidic sensor. a cylindrical aluminum cavity is fabricated to enhance the sensitivity where the quality factor has been increased. two positions of the microfluidic tube have been presented to study of the effect of the electric field direction http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i ahmed adnan al-mudhafar et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 074–079 75 on the liquid sample. the sensor has been tested with several solvents to verify its sensitivity. the complex permittivity of the solvents have been computed from a shift in the resonant frequency of the resonator where the electric field interaction with the volume of the liquid filled. 2. theory and concept 2.1. basic principle of srr and frequency mode to understand the basic phenomena underlying the operation of the split ring resonator, it is first necessary to understand when resonance occurs and understand its electric field configuration for the different frequency modes. resonance the complex permittivity of the solvents have been computed when standing waves are set up in a λ/2 open-circuited microstrip srr [10]; this happens when magnetic energy stored in ring loop equal to the electric energy stored in the gap[11]. single open end of a microstrip transmission line surrounds 70% of the srr as a result tightly coupled used in order to achieve maximum power transfer. shows the capacitive coupling suffered from high crosstalk and inductive coupling far less susceptible to crosstalk [12], so the symmetric feed lines are positioning at a magnetic field antinode were used to excite the split ring by inductive couplings with a smaller degree of capacitive coupling [3, 13] as depicted in the fig.1. electric field of the srr configuration for the different modes where symmetric microstrip lines are in parallel with a separation distance as shown in fig.1. this line support two absolute value of maximum field point for the first two quasi-tem modes of split ring, which are the odd and even modes as shown in the fig.1.(a) even mode it can be seen the positive maximum electric field point (+) at both side of the slit (same voltage sign) even mode capacitance, the absence electric field on the liquid so this capacitance neglected [5]. fig.1.(b) odd mode it can be seen the positive maximum electric field point (+) and negative maximum electric field point (-) at gap (opposite voltage sign) resulting from odd mode capacitance [14], any significant effect on frequency resonator could be a reflection of decrease or increase this capacitance due to variation in the electrical length of ring resonator so odd mode, within the framework of this research, high sensitivity because perturbed by dielectric properties of the liquid within the gap. (a) (b) figure 1. maximum field point for the first two points :(a) even mode, (b) odd mode. 2.2. perturbation theory and liquid complex permittivity slit perturbation resonator arises when the slit is made in the microstrip ring resonator and maximum electric field at both the slit edge [3, 14] so one of its applications is determining complex permittivity of a sample by measuring the shift in frequency resonator bandwidth, insertion loss, and the quality factor (a degree of the loss of a resonant circuit lower loss infers a higher q) when a sample is inserted posited in a place where the electric field is as large as possible into a resonator[5] [10, 15]. under the action of an external electric field on the atoms and molecules of liquid will exercise torque on the electric dipole the dipole will absorb microwave energy and rotate to align with the electric field at a time (called relaxation time constant) hence the positive particles are pushed in the direction of the field while the negative particles in the opposite direction from their equilibrium position causing dipole polarization. as a result of friction force between adjacent dipoles as they rotate toward the electric field, the absorbed energy is converted to heat [3, 16, 17]. relative permittivity of a large number of liquid is a complex number and is expressed as follows [15-20]:  = ′ − 𝐣′′ (1) complex dielectric constant as a function of frequency derived by debye theory are given by [19, 20]: 𝜺′ =  + 𝒔− 𝟏+(𝝎𝝉)𝟐 (2) nomenclature q quality factor x x-coordinates (m)  complex permittivity y y-coordinates(m) ' dielectric constant (real part of complex permittivity) greek symbols ' dielectric loss (loss factor) σ conductivity of copper ( s/m) ω angular frequency λ wavelength (m) fr resonant frequency (hz) ω omega unit of electrical resistance s static permittivity oc celsius temperature ∞ high frequency permittivity ø angle (degree) τ relaxation time constant (sec) subscripts veff effective volume (m 3) ∆ change or shift s sensitivity (mhz) vna vector network analyzer s21 transmission coefficient (db) sma sub-miniature version a connector il insertion loss (db) r radius of the circle (m) ɩ length (m) 76 ahmed adnan al-mudhafar et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 074–079 𝜀′′ = (𝑠−)𝜔𝜏 1+(𝜔𝜏)2 (3) where ′ corresponds to the real part, ′′ to the imaginary part, ω =2πf, τ is relaxation time constant, 𝑠 is the static permittivity (f = 0), and  is the high frequency permittivity (f = ∞).the real part of the permittivity, or dielectric constant, is the reactive part of the permittivity, that is, it represents a relative measure of the electromagnetic energy density that is stored inside the material and an imaginary part influences energy absorption is known as a ''loss factor'' and is a measure of how dissipative or lossy a material is to an external electric field [1]. 2.3. microfluidic positions and sensitivity in the previous sections, the electric field is concentrated as maximum as possible at the gap of the annular ring (odd mode capacitance), which allows the position of the microfluidic channel in that gap vertically or the horizontal position as described in the fig.2. and when the fluid-filled in the tube is placed in that channel this affects srr behavior in terms of resonance frequency and losses which have been used to extract the values of the complex permittivity of the solvent. the effect of that capacitor is a variation for both tube states, but its effect is greater on the resonant properties of the sensor when edge parallel plate capacitor is filled with high dielectric liquid constant[21] but a little shift in the frequency of the srr because more large volume of the liquid exposed to the electric field so can be written that as [3] : ∆𝑓𝑟 1 𝑉𝑒𝑓𝑓 (4) the sensitivity of the sensor increases when there is a noticeable change in its resonance frequency which is expressed by the equation [6]: 𝑆 = ∆𝑓𝑟 ∆′ (5) 3. fabrication of the sensor and micro-fluidic system fig.3. photograph of the fabricated srr and 50ω microstrip transmission line on pcb with dielectric constant substrate fr4 (dielectric thickness is 1.5mm, relative permittivity of 4.6 ± 0.02, and loss tangent 0.017) and dual conductive copper surfaces (thickness of the copper is 35μm, σ is 2.7 ×107 s/m). sma connectors with 50ω used as input and output port of the resonator. general schematics of the srr are presented in fig.4. and table 1 respectively. maximum electric field distribution is at the edge of ring gap so the horizontal channel (width is 1mm, and depth is 0.5mm) was made on the microstrip upper surface from the center to the circumference of the circle passing through the ring gap and vertical channel is made a circular hole (diameter is 1 mm) that crosses through the height of the sensor in the center of the gap as described in fig.4. (a) (b) (c) (d) figure 2. topologies of the microfluidic channel situation on microstrip srr substrate (a) groove channel (b) with a tube fixed in a horizontal position, (c) a round hole (d) with a tube installed in a vertical position. ahmed adnan al-mudhafar et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 074–079 77 figure 4. ssrr dimensions. table 1. dimensions of sensor (mm) r1 r2 r3 r4 r5 r6 r7 x y ø 25 17 15 14 12 1.2 0.65 19 5.4 164o fig.5. shows the system design used in this experiment, a quartz glass tube (outer diameter 1mm and inner diameter 0.5mm and relative permittivity 3.8) which has been used as a microfluidic channel carries liquid samples depends on capillary action so no need to syringe pump device. the sensor is packaged inside an aluminum cylindrical cavity (inner and outer diameter 50mm, 70mm respectively, and an internal height of 40mm) to achieve maximum quality factor by reducing dissipated loss. at horizontal situation, the capillary is put in that groove and passes the cavity wall through the hole which gives the ability to fill the capillary from outside the cavity as shown in focus image in the fig.5.(a) and the fig.5.(b) is shown the horizontal position when the tube is inserted vertically into the hole at the gap and in which the electric field is parallel to the liquid filled in that tube. a portable vector network analyzer (vnakc901v) used to measure the change in the insertion loss and shift in frequency resonator of the sensor due to liquid perturbation. figure 5. experimental configuration with focus image for two tube position 4. measurement and experimental results a vna screenshot as in fig.6. shows the transmission coefficient (s21) was measured at first mode frequency resonator for both horizontal and vertical position of the capillary and when it was air-filled tube, and when it was filled with several solvents have tested such as water, ethanol, and chloroform and the results are shown in fig.7. table 2 lists all these measurements were taken at room temperature 25oc, results show the extracted information from fig.7. such as the shift in resonant frequency which has been used to calculate complex permittivity using debye's model equations (2 & 3) parameters of these equations are taken from [18]. here, the measurement with an empty tube is considered as a reference to compute shift in resonance frequency and alter in loss of the sensor when the tube loaded with solvents. we show from the table 2 shift in frequency decrease with decreasing dielectric constant (') (give an approximately linear relationship) for both positions of the tube . (a) (b) figure 3. photograph of the fabricated srr sensor with sma connectors. (a) top view, (b) bottom view. 78 ahmed adnan al-mudhafar et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 074–079 (a) (b) figure 6. mark 1 appears at the measured s21 peak at the resonant frequency of the sensor when the empty quartz tube in its (a) vertical position (b) and horizontal position the change reading between the measurements of the insertion loss (il) of the sensor when the tube in the horizontal position are higher than that in the vertical position for the same sample due to the volume of the fluid exposed to the electric field is greater in another word, more energy absorbed by dipole of a solvent, and shift in the resonant frequency (∆fr) of the sensor in the vertical position are higher than that in the horizontal position with a rate of change (2 mhz) due to the effective liquid volume (the effective length of the edge gap (2mm) longer than the diameter of the tube(1mm)) is greater, which makes the sensor better sensitive than that in the vertical position and these results are summered in the table 3. eventually, table 4 states the characteristics of the current research work with a different type of pervious art sensor when a tube carried with chloroform. (a) (b) figure 7. measured s21 of the sensor using quartz tube in its (a) vertical position (b) and horizontal position at resonant frequency table 3. comparison of the results between the horizontal and the vertical position of the tube parameter horizontal position vertical position shift in the resonant frequency lower higher losses higher lower sensitivity low better ahmed adnan al-mudhafar et al. /al-qadisiyah journalfor engineering sciences 13 (2020) 074–079 79 table 2. measurement of complex permittivity of common fluids at the resonant frequency and compute the sensitivity liquid horizontal vertical fr (ghz) il (db) j ∆fr(mhz) s (mhz) fr (ghz) il (db) j ∆fr s (mhz) empty 1.0446 8.37  0 0 1.0473 8.55 1 0 0 water 1.0377 8 78.187-j3.93 6.9 0.09 1.04 8.5 78.18-3.94j 7.3 0.1 ethanol 1.04 7.62 13.626-j10 4.6 0.36 1.0424 8.41 13.57-10.02j 5 0.39 chloroform 1.043 7.81 4.714-j0.115 1.6 0.43 1.045 8.48 4.713-0.115j 2.3 0.62 table 4. a comparison of the proposed sensor with pervious work when a tube filled with chloroform at 25oc ref. resonator type substrate type band type active liquid volume (nl) sensitivity (mhz) [3] dsrr rogers 5880 bandpass 7 6.38 [6] srr rogers 5880 bandpass n/a <1.7 [9] dms rogers 5870 bandpass 4500 1.3 [13] srr rogers 5870 bandpass 0.4 0.52 [21] rmc n/a bandpass 0.5 0.26 present work (vertical) srr fr4 stopband 0.4 0.62 present work (horizontal) srr fr4 stopband 0.23 0.43 5. conclusions in summary, a new microwave microfluidic sensor was designed using a microstrip stop-band split-ring resonator with two different positions of the tube where the electric field is as large as possible over there. the sensor has been tested with several solvents to verify its sensitivity is to characterize liquid complex permittivity for both horizontal and vertical position of the tube and we found the loss of the sensor in the first position is higher than that in the second position but the last give noticeable change in the resonance frequency and hence the sensitivity is better. references [1] m. mode, s. mode, s. mode, keysight technologies, (2016). 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[21] h. hamzah, a. abduljabar, j. lees, a. porch, a compact microwave microfluidic sensor using a re-entrant cavity, sensors, 18(3) (2018) 910. article al-qadisiyah journal for engineering sciences 14 (2021) 031–041 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: orashussien1@gmail.com (oras abd al hussien qatta) https://doi.org/10.30772/qjes.v14i1.692 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. coated material (graphene oxide coated sand ) as a new approach in wastewater treatment field :equilibrium and thermodynamic studies oras abd al hussien qatta a*, abbas khalaf mohammad a a chemical engineering department– college of engineering −university of al-qadisiyah-iraq. 1. introduction wastewater is one of the major environmental damages that seriously affect all aspects of life albright et al. [1]. the effects of contaminants can differ depending on their form and source inyinbor adejumoke et al. [2]. dyes in particular known as reactive basic . ,acidic lellis et al. [3]. textile effluent treatment is necessary to protect the environment yaseen et al. [4]. a wide variety of methods for sorption synthetic dyes from water and wastewater have been developed to reduce their environmental effects forgacs et al. [5]..various promising techniques have been used to remove dyes from wastewater. such treatment systems, such as chemical, physical, and biological approaches, have their drawbacks like high expense, radioactive sludge production, etc. the most inexpensive and efficient adsorption process has been the most favoured approach for dye removal seow et al. [6]. graphene oxide, especially as magnetic particles, has recently been used as a suitable adsorbent for a r t i c l e i n f o article history: received 20 september 2020 received in revised form 19 october 2020 accepted 19 october 2020 a b s t r a c t the present work describes a coating process that was carried out on the surface of graphene oxide powder. coated material (go−sand composite) was prepared by soaking screened and washed sand particles (100 µm) with 3% graphene oxide aqueous solution. the coating process was done in two stages, first at a temperature of 105 ◦c for three hours then at 150 ◦c for two hours. ftir spectroscopy was used to investigate the surface of graphite and graphene oxide . adsorption of methylene blue and methyl orange dyes onto the prepared graphene oxide coated sand was done experimentally using batch apparatus with controlled conditions of temperature and stirring. effects of temperature and initial dye concentration for the adsorption process were examined. the analysis of adsorption equilibrium isotherms shows that the experimental data follows fruendlich isotherm model with coefficient of variance (r2) equals to (0.99). this indicates that the adsorption of both dyes onto the go−sand was done on heterogeneous surface with multilayer of dyes molecules. furthermore, basic thermodynamic parameters for the adsorption of both dyes on go−sand were calculated using the most well known relationships. the results indicate that the process is spontaneous and exothermic as the values of gibbs free energy changes lies between -37.078 and -24.231 kj/mole and the values of enthalpy changes lies between -0.669 and -0.348 kj/mole for methylene blue and methyl orange dyes. finally, the activation energy for the adsorption process was determined using arrhenius equation and found to be equals to 28.643 kj/mol and 20.224 kj/mol for methylene blue and methyl orange adsorption, respectively. this proves the physical nature of dyes adsorption on the surface of the adsorbent. © 2021 university of al-qadisiyah. all rights reserved. keywords: coating process support material sand batch adsorption nano material http://qu.edu.iq/ https://doi.org/10.30772/qjes.v14i http://creativecommons.org/licenses/by/4.0/ 32 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 wastewater treatment. it was successfully applied for heavy metals and organic materials (dyes, antibiotics, reactive black 5, etc.) treatments kyzas et al. [7]. coating has been used in many applications such as wear resistance, corrosion protection, anti-fouling, thermal barrier, self-cleaning, etc. for a long time ago. however, its used in the field of coating adsorbents to remove industrial dyes from wastewater was still silent.. it is a modern approach and advanced technology for treating industrial wastewater from organic pollutants such as dyes azha et al. [8]. adsorbent in the form of coated material has benefits over particulate adsorbents such as powders, pellets or beads the objective is to easily separate after the adsorption process (e.g. filtration or centrifugation) as well as to increase the surface area by weight ratio of the adsorbent used and to reduce the amount of solid adsorbent needed azha et al. [9]. the selection of the appropriate support material that used for coating process was one of the important and critical decisions to be taken when preparing for the coating process. so as to use the supporting materials for the purpose of wastewater treatment, it must meet the following criteria: they are non-toxic, insoluble, non-biodegradable, lightweight and nonpolluting; high mechanical and chemical stability, flexibility in general shape, high diffusivity, high proliferation, high biomass retention, low cost and minimal attachment to other organisms martins et al. [10]. there are many types of supported materials which used in the filed of wastewater treatment, but inorganic supported material were the most important which included ceramic and sand polymer materials singh et al. [11]. sand one of the important natural supported materials that widely used in wastewater treatment processes, studies focused on the use of sand as a support material more than others materials such as clay or clay minerals due to its distinctive characteristics and its meets the effective adsorption requirements jada et al. [12]. the study focuses on the use of sand as an inorganic support material in the field of wastewater treatment. also, this work explains the stages of the coating process that was carried out on the surface of graphene oxide with specific conditions. studying of the equilibrium and thermodynamic characteristics for the adsorption process was one of the important analysis which applied in the present work. 2. experimental work 2.1. materials sand was collected from al-najaf sand quarry. also, chemicals that used in the practical aspect have high purities with analytical grades including, h2so4 (aldrich, germany), h3po4 (aldrich, usa), original graphite powder (>150 µm), potassium permanganate (alpha chemika, iso co., india), ethanol (aldrich, germany), hydrogen peroxide (panreac, germany). 2.2. coated material preparation (graphene oxide−sand composite) preparation of coated adsorbent (go−sand) was included two main steps. firstly, preparation of graphene oxide powder. secondly, coating the surface of the sand grains with prepared graphene oxide. 2.2.1. apparatus used for coating process the apparatus shown photographically and schematically in fig. (1) and (2) was used for coating of sand grains with graphene oxide. a coating container was used with 1000 ml pyrex glass beaker (simax, germany). the beaker was fitted with a glass stir bar for mixing the coating mixture manually. a digitally operated drying oven (memmert, germany) was used to dry any excessive quantity of solvent . figure 1. photographic picture of the apparatus used for coating sand with graphene oxide. nomenclature ea activation energy (kj/mol) qe ce adsorption capacity (mg/g) concentration of adsorbate solution c2 concentration of solution after dilution (mg/l) c1 concentration of solution before dilution (mg/l). kf ke δh◦ δs◦ constant of freundlich dimensionless equilibrium constant enthalpy energy change (kj/mol) entropy energy change (j/mol.k) a frequency factor go δg◦ c0 gaphene oxide gipps free energy (kj/mol) initial concentration n b intensity of adsorption langmuir isotherm constant (l/mg) qm mb mo qm v1 v2 maximum adsorption capacity (mg/g) methylene blue methyl orange theoretical adsorption capacity (mg/g) volume of solution before dilution (litre) volume of the distilled water required for dilution in litre. oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 33 figure 2. schematic diagram of the apparatus used for coating process. 2.2.2. procedure modified hummer method was used for preparation of graphene oxide powder andrijanto et al. [13]. a 9:1 mixture of two concentrated sulphuric acids (h2so4, 98%) and phosphoric acid (h3po4, 70%) was added to the conical flask, then (3 gram) from the original graphite powder (>150 μm) was put in the flask. after that (18 gram) from the permanganate potassium (kmno4) was slowly added to the mixture, after this addition, the temperature steadily rose to (35 ◦c) due to the occurrence of an oxidation reaction. then the mixture heated up until the temperature reaches 50 ◦c with continuing to stir for 12 hours. after that, decreasing the solution temperature to room temperature. finally, hydrogen peroxide added (3 ml) (30%, h2o2), fig. (3) shows the schematic diagram for the apparatus used for preparing grapheme oxide powder. the finale product was washed and filtered by using filtration apparatus which show in fig. (4).finally. produced graphene oxide was dried in drying oven at 60 ◦c for three hours. figure 3. schematic diagram of apparatus used for preparation of grapheme oxide . figure 4. photographic picture for filtration apparatus. after preparing of graphene oxide powder the step followed that was coating process. the process was performed under certain conditions in the laboratory. firstly, sand was prepared for coating, it was sieved by using laboratory sieving device which show in fig. (5). the device consisted of six section each section has its own mesh number and the size of diameter in ( mic). this test was important to select which section was appropriate in terms of quantity, mesh number and diameter, after sieving the second section was chosen (100 mic). figure 5. photographic picture of laboratory sieving machine. then sand was washed more than one time with tap water and soaked with 10 % hcl for 6 hours to remove impurities and salts, after that, drying oven was used to dry the clean sand. the preparation of sand grains for coating process shows in fig. (6). 34 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 figure 6. photographic picture of the steps of preparation sand for coating process. after washing and drying the sand, 30 gram of dried sand were taken and submerged in (50 ml) from 3% suspended solution of distilled water and grapheme oxide. then heated the mixture for three hours at 105 ◦c for water evaporation. after that the mixture was heated at 150 ◦c for an additional 2 hours to stabilize the graphene oxide on the sand grain surface. the final product was resulted from the coating process was a black powder of sand coated by graphene oxide which represent the adsorbent material for waste water treatment process. fig. (7) shows a photographic picture of prepared graphene oxide−sand. figure 7 . photographic picture for go-sand composite after coating process. 2.3. equilibrium experiment several methylene blue and methyl orange dyes solutions were prepared according to the dilution law [14]: 𝐶1 ∗ 𝑉1 = 𝐶2 ∗ 𝑉2 ……………….(1) fig. (8) shows the stocks solution. figure 8 . photographic picture of the stock solution. adsorption equilibrium experiments were done in two steps. firstly, the equilibrium time was determined at the highest dyes concentration and the lowest temperature to ensure obtaining enough time for mass transfer. secondly, dyes concentration in aqueous solutions as a function of dyes concentration in the solid phase was obtained at different temperatures. a 500 ml three nick conical flask (goel, germany) was used as an adsorption chamber. a glass thermometer was immersed inside the flask for measuring and recording of adsorption temperature. the flask was equipped with pyrex glass recycling condenser to ensure retarding of any vapors from adsorption mixture. an antifreeze chiller (hysc, korea) was used to supply condensing media at (-5 ◦c) for the recycling condenser. 1000 ml pyrex glass beaker (simax, germany) covered via a layer of glass wool insulation material was used as a water bath for the adsorption mixture. a thermo couple connected to a digital recorder (micro max, germany) was putted inside the beaker for continuous monitoring of water bath temperature. the hole adsorption equipment was putted over a hot plate magnetic stirrer (sh-2, germany) for supplying necessary heat required for the water bath as well as providing the vigorous mixing of adsorption mixture. fig. (9) and (10) show photographically and schematically batch adsorption device. figure 9 . photographic picture for batch adsorption system. oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 35 figure 10 .schematic diagram for batch adsorption system. then, a set of experiments were conducted to examine the effect of temperature and initial concentration on the adsorption of methylene blue and methyl orange from aqueous solution onto the prepared super sand. this was done by taking a range of concentrations (50, 100, 150, 160, 180, 200) ppm of basic dye (methylene blue) and acidic dye (methyl orange) at different temperatures (20, 25, 30, 35) ◦c with constant contact time 3 hours. each experiment was done by putting 1 gram of the adsorbent material (super sand) in a pyrex flask with (30 ml) of the dye solution. the colour of solutions for the two dyes before and after the adsorption process were shown in fig. (11). figure 11. photographic picture for methylene blue and methyl orange before and after adsorption . 3. result and discussion 3.1. dyes concentration by photometric method ultraviolet/visible absorption spectrometer (uv−vis) analyzes the light beam reflected from the surface of the sample or after passing through it. where there is a linear relationship between the concentration of material and absorption. this makes the uv spectroscopy very important in making quantitative measurements [15]. the wave length of the methylene blue and methyl orange dyes was checked firstly. this was done by putting a sample from the two dyes solutions in the sample cell of the machine. distilled water was used as a comparative solution where it was putted in the solvent cell. after that, a scan for the whole wave length range was performed to analyze the peaks of the spectrum. fig. (12 and 13) show the calibration curves of methylene blue and methyl orange dyes. figure 12. calibration curve of methyl orange dye . figure 13. calibration curve of methylene blue dye. 3.2. characterization of prepared graphene oxide fourier transform infrared (ftir) spectroscopy was used to investigate the presence of functional groups on the surface of graphene oxide. fig. (14) & (15) show the spectra of graphite and graphene oxide. from fig. (15) , the characteristic peaks were appeared in different in different wavenumber. the peak falls at (3332) cm-1 refers to the presence of hydroxyl stretching vibration (-oh). several researchers suggested that the peaks at the range (3000−3500) cm-1 refers to (c-oh) groups on the surface of go [16, 17]. in addition [18] study showed that the hydrophilic 36 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 property of graphene oxide due to the presence of the hydroxyl functional group. peak at (2973) cm-1 refers to sp3 (c-h) group which indicates that the prepared graphene oxide was produced in acidic media. this conclusion was based on the evidence recognized by aziz et al. [19]. peak at (1390) cm-1 indicates the presence of carboxyl stretching vibration (c=o) while the peaks at (1088) cm-1, (1045) cm-1 and (879) cm1 refer to (c-o) stretching vibration. the presence of all these functional groups (epoxy, hydroxyl, carboxyl) on the surface of prepared graphene oxide proves the successful preparation process which was used in our experimental work. this results were based on the observations that done by several researchers[17, 20]. figure 14. fourier transform infrared (ftir) for graphite. figure 15. fourier transform infrared (ftir) for graphene oxide. 3.3. equilibrium study of adsorption isothermal information analyzes with the application of characteristic isothermal modeling is a major development in determining the appropriate model that can be used for design purposes. as a result, the relationship of equilibrium data that uses either a theoretical or experimental formula to understand and predict the degree of adsorption, in choosing the most extreme adsorption limit for a given adsorbent foo et al. [21]. fig. (16 and 17) represent the equilibrium adsorption isotherms curves for the acidic dye (methyl orange) and the basic dye (methylene blue) on the surface of the prepared graphene oxide coated sand adsorbent. these curves were plotted for the range of concentration (50−200) ppm at different temperatures (20, 25, 30, 35 ◦c). figure 16. adsorption equilibrium isotherms for methyl orange adsorbed on the go−sand at different temperatures. figure 17. adsorption equilibrium isotherms for methylene blue adsorbed on the go−sand at different temperatures. it could be recognized from these figures that there is a proportional relationship between the concentration of dyes in the solution and its concentration in the adsorbed phase. this is clearly shown from the shape of isotherms curves that are of classical adsorption type. this means that any increasing of concentration of dye in the solution increases the concentration of dye on the surface of the adsorbent. but this proportionality becomes less notable at high concentrations of dyes in the solution because the adsorbent reaches its maximum capacity. the values of maximum capacities for the prepared go−sand is shown in table 1. figure (14): fourier transform infrared (ftir) for graphite. oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 37 table (1) maximum capacities of go−sand for methylene blue and methyl orange dyes. 3.3.1. langmuir and freundlich models langmuir and freundlich adsorption isotherm models were used to correlate the experimental adsorption data of methylene blue and methyl orange onto go−sand composite. these models were used in the present study because they are the most well known equations that could represent the adsorption of solute in aqueous solution onto a solid adsorbent [22]. langmuir adsorption isotherm represents the adsorption of solute that limits to a single monolayer of solute molecules on the solid adsorbent. this is based on the langmuir theory of adsorption which assume the surface of the solid adsorbent as a homogeneous surface. however, langmuir adsorption isotherm equation could be represented mathematically as [23]: 𝑞𝑒 = 𝑄𝑚 𝑏 𝐶𝑒/(1 + 𝑏 𝐶𝑒) ……………………….. (2) freundlich adsorption isotherm represents the adsorption of solute as a multilayer of molecules onto the heterogeneous surface of solid adsorbent. freundlich adsorption isotherm equation could be represented mathematically as [22]: 𝑞𝑒 = 𝐾𝑓 𝐶𝑒 1 𝑛 …………………………..................(3) langmuir and freundlich adsorption isotherm equations were expressed in linear forms respectively as follow: 𝐶𝑒/𝑞𝑒 = 1/(𝑄𝑚 𝑏) + 1/𝑄𝑚 𝐶𝑒 ……………….(4) 𝐿𝑜𝑔 𝑞𝑒 = 𝐿𝑜𝑔 𝐾𝑓 + 1/𝑛 𝐿𝑜𝑔 𝐶𝑒 ………………...(5) the experimental data for adsorption of methylene blue and methyl orange on prepared go−sand composite were correlated with the linearized form of langmuir and freundlich adsorption equations and shown in fig. (18 and 21). it was clearly observed from these figures that the experimental data corresponding the freundlich isotherm very well. this result indicates that the adsorption methylene blue and methyl orange onto the go−sand was empirical and occurred on heterogeneous surface and also due to the high concentrations used in the present work. figure 18. linearized form of fruendlich isotherm model for methyl orange adsorbed at different temperatures. figure 19. linearized form of fruendlich isotherm model for methylene blue. adsorbed at different temperatures. figure 20. linearized form of langmuir isotherm model for methyl orange adsorbed at different temperatures. figure 21. linearized form of langmuir isotherm model for methylene blue adsorbed at different temperatures. this congruence with freundlich isotherm could be clearly evident by recognizing the values of confidence level (r2). tables (2 and 3) show the comparison between the langmuir and freundlich isotherms for methylene blue and methyl orange dyes equilibrium adsorption data. temp. ◦c methylene blue methyl orange ce qe ce qe 20 1.922 5.983 15.667 5.682 25 2.011 5.612 16.321 5.322 30 2.126 5.376 17.511 5.087 35 2.157 5.102 18.563 4.722 38 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 table (2): isotherm parameters for methyl orange at temperature range (20–35) ◦c. table (3): isotherm parameters for methylene blue at temperature range (20 – 35) ◦c. 3.3.2. effect of initial concentration the initial concentration of the dyes is an important tool in the study of the adsorption capacity. and the removal percentage of dye zhang et al. [24],which was calculated by the following equation wang et al. [25]: % 𝑟𝑒𝑚𝑜𝑣𝑒𝑙 = 𝐶0−𝐶𝑒 𝐶0 ∗ 100 …………………………………(6) fig. (22 and 25) show the initial concentration of methyl orange and methylene blue dyes in the solution as a function of removal percentage of them due to adsorption which on the surface of graphene oxide coated sand. figure 22. removal percentage of methylene blue and methyl orange dyes for different initial concentration at 20 ◦c. figure 23. removal percentage of methylene blue and methyl orange dyes for different initial concentration at 25 ◦c. figure 24. removal percentage of methylene blue and methyl orange dyes for different initial concentration at 30 ◦c. figure 25. removal percentage of methylene blue and methyl orange dyes for different initial concentration at 35 ◦c. it was clearly shown from these figures that an increasing of the initial concentration of the two dyes in the solution associated with a decreasing of the removal percentage. however, the increase in initial concentration enhances the adsorption capacity but diminishes the removal percentage of dye. this clearly observed from fig. (16 & 17) and (22−25), where the removal percentage at 20 ◦c decreased from 99.55% to the 70.44% for methylene blue and decreased from 83.32% to 61.22% for methyl orange. this behavior is in agreement with study by foo et al. [21]. this behavior may be explained as follows. in most cases of low concentrations of dyes in solution, the ratio of the initial number of dye molecules to the available surface area is small hence, the partial adsorption is independent on the temp. ◦c langmuir model freundlich model qm b r2 kf n r2 20 25 30 35 5.682 5.322 5.087 4.722 0.066 0.05 0.049 0.048 0.5448 0.75 0.4601 0.603 0.448 0.293 0.176 0.091 1.019 0.949 1.115 0.848 0.9961 0.9971 0.9974 0.9999 temp.◦c langmuir model freundlich model qm b r2 kf n r2 20 25 30 35 5.983 5.612 5.376 5.102 0.702 0.638 0.574 0.537 0.2773 0.3134 0.2958 0.2142 0.265 0.325 0.405 0.505 0.975 0.963 0.917 0.874 0.9985 0.9988 0.9988 0.9986 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 39 initial concentrations. although, in high concentrations of dyes in solution, the available adsorption sites become less as a result of reaching the adsorption sites to the saturation state. however, figures (22− 25) indicate that there is an optimal value for the initial concentration of both dyes in the solution. this optimal value is about 100 mg/l where the relationship between the removal percentage and the initial concentration up to this value is approximately a horizontal line. 3.3.3. effect of temperature in the adsorption process it is very important to know the extent to which the temperature affects the efficiency of the adsorbents corda et al. [26]. fig. (16 and 17) show the effect of temperature on the adsorption capacity of go−sand for methyl orange and methylene blue dyes. the temperature range using for the adsorption process is (20 – 35) ◦c, it was clearly observed from these figures that an increase in the temperature causes a decrease in the adsorption capacity of the two dyes. this behavior refers that the adsorption phenomena is an exothermic process, this result is in agreement with study by yagub et al. [27]. they expressed that if the the adsorption capacity increases with increasing temperature, this means adsorption is an endothermic process. this is due to the increased susceptibility of the dye molecules and the expansion in the active sites upon increase in temperature. while the adsorption capacity decreases with increase in temperature, this means that the process is exothermic. this behavior may be due to the weakening of the attraction forces between the dye. molecules with the active sites on the surface of the adsorbent upon increased temperature. fig. (22 & 25) show the effect of temperature on the removal percentage of dyes. the figures indicate that an increase in temperature leads to a decrease in the removal percentage of the two dyes. where, the removal of methylene blue decreased from 99.55% to 87.12% with increasing the temperature from 20 ◦c to 35 ◦c. also, the removal of methyl orange decreased from 83.32 % to 75.33% with the same increasing in temperature. this behavior is in agreement with the study by gupta et al. [28]. they explained that the adsorption forces between the dye molecules and the active sites become weak when the temperature increases, which leads to a decrease in the removal percentage of dye. 3.3.4. effect of adsorbate type fig. (22 & 25) show that the go−sand composite is more effective in removing methylene blue than the methyl orange. where, the maximum percentage of removal methylene blue reached to 99.55% at 20 ◦c. while the maximum percentage of removal methyl orange reached to 83.32% at the same temperature. this result is due to the extent of attraction and repulsion between the active sites on the surface of the go−sand and the different charges of the dye molecules. for this reason, the attraction is greater between the surface charges (acidic media) with methylene blue (basic dye) and less with methyl orange (acidic dye). this behavior is in agreement with the study by santoso et al. [29]. the study showed that graphene oxide has a high efficiency in removing methylene blue from aqueous solutions due to the attraction between their different charges. in comparison this result with study by shahabuddin et al. [30], they used poly aniline coated graphene oxide for removal methylene blue and methyl orange dyes from aqueous solution. the results showed that methylene blue removal percentage was 57% which it was higher than of methyl orange 36%. they concluded that the surface of the graphene oxide contain various functional groups such as (epoxy and hydroxyl), also the presence of sp3 hybrid framework that makes it effective in removing basic dyes such as mb more than mo. 3.4. kinetics and thermodynamic studies the estimation of the thermodynamic parameters depend on the value of the thermodynamic equilibrium constant (ke). the mathematical equations used in the thermodynamic calculations could be presented as [31]: ∆𝐺° = −𝑅𝑇 𝑙𝑛(𝐾𝑒) ……………………. (7) ∆𝐺° = ∆𝐻° − 𝑇∆𝑆° ………………………(8) 𝑙𝑛 (𝐾𝑒) = −(∆𝐻°)/𝑅𝑇 + (∆𝑆°)/𝑅 ……….(9) 𝐾𝑒 = 𝑞𝑒/𝑞𝑚/(1 − 𝑞𝑒/𝑞𝑚)(𝐶𝑒/(𝐶°))………(10) fig. (26 and 27) represent the plot of (lnke) as function of the inverse of the temperature (1/t) for adsorption of methyl orange and methylene blue dyes onto the go− sand. the values enthalpy change (∆h◦) and entropy change (∆s◦) were computed from the slops and intercepts of these lines. figure 26. thermodynamic plot of (lnke) versus (1/t) for adsorption of methyl orange at different concentrations. figure 27. thermodynamic plot of (lnke) versus (1/t) for adsorption of methylene blue at different concentrations. it was clearly observed from the figures that the slopes and intercepts of all lines are positive. therefore, the adsorption of methyl orange and methylene blue on the go−sand is exothermic process since the enthalpy changes are always negative. furthermore, the process was happened spontaneously because the values of entropy changes are always positive. in addition, the positive values of the entropy changes (∆s◦) refer to the randomness of the surface. this result is in agreement with study did by alghamdi et al.[32]. they used graphene oxide composite for the removal of azo dyes from aqueous solution. they computed the values of (δh◦, δs◦ 40 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 and δg◦). their results gave the same idea for the nature of the adsorption process. they concluded that the process was exothermic and spontaneous. activation energy (ea) for adsorption of methyl orange and methylene blue on the go−sand was studied and computed by applying arrhenius equation saha et al. [33]: 𝑙𝑛𝑘 = 𝑙𝑛𝐴 − 𝐸𝑎/𝑅𝑇 ……………………..(11) fig. (28 and 29) represent a plot of (lnk) versus (1/t) for methyl orange and methylene blue adsorption on go−sand. the values of the activation energies were determined from the slops of the figures for the two dyes. tables (4) & (5) show the values of δg◦ , δs◦ and δh energies for methylene blue and methyl orange dyes. figure 28. arrhenius plot for methyl orange adsorption at temperature range (20 − 35) ◦c. figure 29. arrhenius plot for methylene blue adsorption at temperature range (20 − 35) ◦c. table (4): thermodynamic parameter for the adsorption of methyl orange on the super sand at temperature range (20−35) ◦c. table (5): thermodynamic parameter for the adsorption of methylene blue on the super sand at temperature range (20−35) ◦c. 4. conclusions this research demonstrates the use of coated materials as a new approach in wastewater treatment. coating process gave a good result of graphene oxide–sand composite with high dyes removal efficiency from aqueous solution. this work will conclude on a variety of important points:  the product of the coating process was a homogeneous compound of sand and graphene oxide. the process was completed successfully and gave graphene oxide fixed well on the surface of sand grains after five hours without the need for reheating.  ftir spectra was showed the chemical structure of graphene oxide, the result expresses different functional groups (epoxy, hydroxyl and carboxyl) distributed on the surface that indicate the success of the preparation process.  the equilibrium adsorption isotherm were applied on the experimental data showed that the freundlich isotherm fitted well the experimental adsorption data with confidence level 0.99.  go−sand material has high efficiency in removing, where the maximum percentages removal of methylene blue and methyl orange equals to 99.55% and 83.22% , respectively.  methylene blue has higher adsorption capacity than methyl orange, this may be due to the difference in the attracting forces between the surface of the adsorbent and the charges carried by the dyes.  thermodynamic study showed that the adsorption process was spontaneous and exothermic process in nature, this due to the negative values of the gibbs free energy change (δg◦) and enthalpy energy change (δh◦).  the values of gibbs free energy changes lies between -37.078 and 24.231 kj/mole and the values of enthalpy changes lies between 0.669 and -0.348 kj/mole. this result indicates that the adsorption process of the present study could be suggested as physical adsorption in addition, the activation energy was studied for the two dyes and the result showed that the activation energy were equals to ea=28.643 kj/mol and ea=20.224 kj/mol for methylene blue and methyl orange, respectively. it was concluded from these results that the energy needed for interacting the adsorbate and the adsorbent are not high and this refers to the physical nature of the process. co nc. ppm ∆h ◦ ∆s◦ ∆g◦ (kj/mol) 293 k 298 k 303 k 308 k 50 100 150 160 180 200 0.6 69 0.6 29 0.5 77 0.6 54 0.6 89 0.5 1.043 0.837 0.569 0.756 0.793 0.416 25.358 -60.33 -26.537 -28.323 -29.902 -31.405 -31.962 25.1 89 26.2 77 28.0 26 29.0 32 30.2 53 32.3 24.2 31 26.2 02 28.0 23 28.7 64 29.7 23 30.6 24.9 57 26.2 42 27.8 71 25.4 13 29.1 65 29.4 conc. ppm ∆h◦ ∆s◦ ∆g◦ (kj/mol) 293 k 298 k 303 k 308 k 50 100 150 160 180 200 -0.402 -0.348 -0.427 -0.559 -0.479 -0.459 0.085 0.357 0.198 0.171 0.198 0.351 -30.053 60.33 -31.225 -33.877 -35.098 -36.540 -37.078 -30.236 -31.225 -33.877 -35.098 -36.540 -35.765 -30.332 -31.469 -33.376 -28.027 -33.827 -34.227 -30.337 -31.602 -33.674 -34.259 -34.385 -34.901 oras abd al hussien qatta , abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 14 (2021) 031–041 41 references [1] r. albright et al., "ocean acidification: linking science to management solutions using the great barrier reef as a case study," journal of environmental management, vol. 182, pp. 641-650, 2016. 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[33] p. saha and s. chowdhury, "insight into adsorption thermodynamics," thermodynamics, vol. 16, pp. 349-364, 2011. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 565 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the effect of fin’s height and circular perforated on the natural convection of the vertical rectangular fins ali a. f. al-hamadani, department of mechanical engineering, college of engineering, wasit university, wasit, iraq. e-mail: aalhamadani@uowasit.edu.iq khaleel saleem jebur ogaili, department of mechanical engineering, college of engineering, wasit university, wasit, iraq. e-mail: khaleel.ogaili@usq.edu.au ahmed a. y. al-waaly, department of mechanical engineering, college of engineering, wasit university, wasit, iraq. e-mail: aalwaaly@uowasit.edu.iq received on 24 august 2017 accepted on 13 december 2017 published on 20 february 2018 doi: 10.30772/qjes.v10i4.505 abstract: the safe operation of any device is necessary, but it requires a suitable condition such as dissipated the heat generated. a heat sink with vertical rectangular fins was improved using a circular perforated with diameter of 6mm for different fins height 6 cm, 8 cm and 10 cm. an experimental study was conducted to investigate the effect of circular perforated on the natural convection heat transfer of a vertical rectangular fin. different numbers of circular perforated 2, 3 and 5 were studied. the results showed that the heat transfer for the height 6cm is higher as compared with 8cm and 10 cm. moreover, the coefficient of heat transfer increases with the increased of the number of the circular perforation. for the fin height 6cm with five circular perforated, the heat transfer coefficient of the natural convection is 30 w/m 2 o c. keywords: fins, natural, circular perforated, heat transfer, experimental. introduction the enhancement of heat transfer by natural convection is an essential matter of thermal applications. the reduction of the extreme heat rate from electronic devices is necessary to ensure steady and continuous safe operation. the heat transfer can be improved by increasing the heat transfer area between the heat transfer surface and the outside environment. the extended surfaces (fins) are used to increase heat transfer in many applications. the rectangular fins are frequently used because of their easy construction, inexpensive cost and active cooling capability. burak y. [1] studied different sets of rectangular fins with mailto:aalhamadani@uowasit.edu.iq mailto:khaleel.ogaili@usq.edu.au mailto:aalwaaly@uowasit.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 566 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. natural convection. the fin length and fin spacing was varied with constant thickness of 3 mm. the input heat supplied was varied from 25 w to 125 w. burak y. concluded that the best fin spacing is between 0.88 cm and 1.47 cm. mahdi f. et al. [2] simulated the free convection on vertical surfaces using computational fluid dynamic software. they concluded that heat transfer rate increases for fin spacing 5.84 and 6.42 mm, after that the heat transfer rate starts to decrease. mahdi f. et al. confirmed that the coefficient of natural convection varies with the fin’s height, length, fin spacing, and the temperature difference between fin’s and the ambient temperature. goshayeshi, et al. (2009) [3] investigated numerically the effect of horizontal and vertical surface of the fin on the fin’s performance. the results demonstrate that the vertical plate with vertical fins gives the greatest performance for normal cooling. al-widyan, et al. [4] investigated the effect of circular perforations attached to the surface on the performance of a rectangular fin. their numerical analysis shows that the heat transfer from the perforated fin increased with grashof number and reduction of the spacing between the holes. golnoosh mostafavi et al. [5] studied steady-state of rectangular interrupted fin arrays. they concluded that adding of interruptions to a single vertical plate will improve heat transfer characteristics. they developed a new relationship to calculate the nusselt. ali, et al. [6] presented numerical and experimental analyses for a forced convection through staggered punched pin fins in a rectangular channel. they concluded that nusselt number is increased with horizontal/vertical (hv) perforations than those for solid pins. wadhah et al. [7] examined the behavior of heat sinks with different number of circular perforations in a rectangular fin plate. they found the coefficient of heat transfer increased with number of holes. numerical results of shaeri, et al. [8] showed that the rectangular perforated fins gave higher heat transfer than the solid fins. in the present study the combined effect of fin length with a number of circular perforated for optimized the performance of the fin has not been studied. therefore, an experimental work has been achieved to know the combined effect of fin length with many circular perforated. to do this purpose the six fins configuration was used. 1. materials methods the study analyzed of free convection from rectangular extended surface (fins) with circular perforated has been investigated. this type of fins used to enhance the heat transfer and the area of heat transfer. the number and dimension of perforations were significant paremeter on heat dissipation [7]. the behavior of thermal performance of fins can be analyzed. the length and width of heat sink were 300 mm and 110 mm respectively. the heat supplied (qgen) through base plate and fins by using heater. the heat transferred across the fin by conduction qcond. the other mode of heat transfer such as convection and radiation also occur between the fins and surrounding [9]. (1) the heat generating is calculated as follows: (2) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 567 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the heat transferred by radiation is calculated as follows: (3) where: ɛ : emissivity surface factor equal to (0.04) [4] ssur: shape factor and equal = 1 [4] therefore, the heat transferred is calculated by convection as follows: (4) equation 5 determine the heat transfer coefficient in free convection: (5) the area of base plate is : (6) area of circular perforated : (7) exposed fin area : (8) totally exposed area : (9) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 568 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. then, the total surface area with six fins is 0.2412 m 2 . the difference temperature in equation (5) represents the average temperature of the base fin and the air temperature. the temperature of the base fin is calculated as follows: (10) the film temperature ( ) is computed by eq. 11: (11) this temperature is taken to calculate the physical properties of the working fluid (air). according to the values of temperature and physical properties taken from the tables in reference [4], any physical property at any temperature within the range used in this study can be obtained. nusselt number is determined by eq. 12: (12) 2. experimental setup and methodology six fins were inserted into a rectangular aluminum base. the base plate dimensions are l = 300 mm and w = 110 mm with base thickness equal to 10mm. different fins heights have been chosen (60, 80 and 100 mm) with thickness t=5mm and different number of perforates n=2, 3, 5. fins spacing was s=12.5 mm. figure 1 shows rectangular fins with five circular perforated heat sink. figure 1: the photograph of the fins geometry. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 569 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the following procedure has been followed: the fins have been inserted into grooves in the base plate to form fin arrays. the fins array was placed on four electric heaters to mimic heat generation. six thermocouples were fixed at different positions on the base plate. a voltage regulator was used to supply five different voltages (50, 75, 100, 125 and 150 v) to generate various heat fluxes. temperature measurements were recorded using digital thermometer. ambient temperature was measured. the temperature measurements were recorded until a steady state is achieved. average temperature of the thermocouples was calculated. figure 2: photograph of the test rig with the measuring instruments. 3. results and discussion different fin heights have been investigated with varying the size of the circular perforated. the erformance of fins was estimated by using nu, h and ra. the first experiment that used different fin of circular perforated (fcp) with 2,3 and 5 number of fins and height length of fin 6 ,8 and 10 cm. figure 3 shows the heat transfer coefficient (h) with temperature differences (tav -tair), nu and tav for fin of circular perforated (fcp) with 2,3 and 5 number of fins of 6, 8 and 10 cm height of fin respectively. it showed the heat transfer coefficient and nu were increased with fins of two circular perforated (fcp2) with 6 cm fin’s height. the is due to the small surface area of the fin(s), see eq(5). power supply voltmeter digital thermometer heater fin s thermocouple al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 570 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 20 40 60 80 100 120 140 160 180 200 12 14 16 18 20 22 24 26 28 30 h ( w /m 2 o c ) tav ta ( o c) fcp2 with h=6 cm fcp3 with h=8 cm fcp5 with h=10 cm figure 3: the heat transfer coefficient and temperature difference for different fin height and different number of circular perforated. figure 4 depicts the heat transfer coefficient (h) and the rate of heat transfer qc with different height of fin. the enhancement in heat transfer of fcp2 with 6 cm fin’s height is higher than the others. 0 200 400 600 800 1000 1200 1400 12 14 16 18 20 22 24 26 28 30 fcp2 with h=6 cm fcp3 with h=8 cm fcp5 with h=10 cm h e a t tr a n s fe r c o e fi c ie n t, w /m 2 o c heat transfer rate, w figure 4: heat transfer coefficient and the rate of heat transfer for different fcp with different fin height. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 571 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5 previal the nu number and temperature differences for different fcp. the fin of 6 cm height of fin give high nu approximately 270 which is represented high value if we compared with 8 and 10 cm. the enhancement due to less area with 6 cm. 20 40 60 80 100 120 140 160 180 200 140 160 180 200 220 240 260 280 fcp2 with h=6 cm fcp3 with h=8 cm fcp5 with h=10 cm n u tav ta ( o c) figure 5: variation of nu with temperature different for different fcp with different fin height. the number of fcp has been investigated with different fin height as shown figures 6 and 7. 40 60 80 100 120 140 160 180 200 220 12 14 16 18 20 22 24 26 28 30 h e a t tr a n s fe r c o e fi c ie n t, w /m 2 o c t av , o c h =6 cm h =8 cm n = 3 figure 6: the heat transfer coefficient with the average temperature for height of fins 6 and 8 cm with with fcp3. it prevail that the fcp5 give high heat transfer coefficient as well as the best fin height was 6 cm. this results because when increased the no of circular perforated will cause enhancement of heat transfer. furthermore the fins will become lighter from other and fcp5 has economical benefit. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 572 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 40 60 80 100 120 140 160 180 200 220 12 14 16 18 20 22 24 26 28 30 h e a t tr a n s fe r c o e ff ic ie n t, w /m 2 o c t av , o c h=6 cm h=10 cm n = 5 figure 7: the heat transfer coefficient with the average temperature for height of fins 6 and 10 cm with fcp5. conclusions the study was carried out to examine the fin with circular perforations as heat sinks. the experimental work was conducted. the set of the perforations included 2,3 and 5 circular perforations (holes) for fin height 6, 8 and 10 cm respectively. the effects of different fin height, number of circular perforated and heat flux on the performance of fin collections was showed. the heat transfer coefficient enhanced for fcp2 with h=6cm compared with fcp3 with h=8 cm and fcp5 with h=10 cm. the heat transfer increase with height of fin the best one with fcp2 with h= 6 cm. the nu increased with ra and the max nu is 270 with fcp2 with h= 6 cm. for the fin height 6 cm with five circular perforated, the heat transfer coefficient of the natural convection was 30 w/m2 oc. acknowledgements the authors would like to acknowledge the department of mechanical engineering, college of engineering, wasit university for their support to do the experimental work. references 1. yazicioğlu, b., performance of rectangular fins on vertical base in free convection, m.sc. thesis technical university of middle east, 2005. 2. fahiminia, m.; naserian, m.m.; goshayeshi, h.r.; majidian, d., investigation of natural convection heat transfer coefficient on extended vertical base plats, energy and power engineering, 3, 174-180, 2011. 3. goshayeshi, h. r; ampofo, f. heat transfer by natural convection from a vertical and horizontal surfaces using vertical fins, energy and power engineering, 85-89. doi:10.4236/epe.(2009).1201, 2009. 4. al-widyan, m.i.; and al-shaarawi, a., numerical investigation of heat transfer enhancement for a perforated fin in natural convection, international journal of engineering research and applications (ijera), 2, issue 1, 175-184, 2012. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 573 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 5. mostafavi, g.; ahmadi, m., effect of fin interruption on natural convection heat transfer from a rectangular interrupted single-wall, proceedings of the asme 2013 international technical conference and exhibition on packaging and integration of electronic and photonic microsystems interpack2013, burlingame, ca, usa. p. 1-8, 2013. 6. baqir, a.s.; qasim, a.; adnan, a., experimental study for staggered perforated array of pins link fins in a rectangular air cross flow, the iraqi journal for mechanical and material engineering, 14, no. 2, 261-275, 2014. 7. aldoori, w.h.a., enhancement of natural convection heat transfer from rectangular fins by circular perforations, international journal of automotive and mechanical engineering (ijame), 4, 428-436, 2011. 8. shaeri, m.r.; yaghoubi, m.; jafarpur, k., heat transfer analysis of lateral perforated fin heat sinks, applied energy, 86, 2019–2029, 2009. 9. incropera,‎ f.p.; dewitt,‎ d.p.; bergman,‎ t.l.; lavine, a.s., fundamentals of heat and mass transfer, john wiley & sons; 6th edition (march 10, 2006). https://www.amazon.com/s/ref=dp_byline_sr_book_1?ie=utf8&text=frank+p.+incropera&search-alias=books&field-author=frank+p.+incropera&sort=relevancerank https://www.amazon.com/s/ref=dp_byline_sr_book_2?ie=utf8&text=david+p.+dewitt&search-alias=books&field-author=david+p.+dewitt&sort=relevancerank https://www.amazon.com/s/ref=dp_byline_sr_book_3?ie=utf8&text=theodore+l.+bergman&search-alias=books&field-author=theodore+l.+bergman&sort=relevancerank https://www.amazon.com/s/ref=dp_byline_sr_book_4?ie=utf8&text=adrienne+s.+lavine&search-alias=books&field-author=adrienne+s.+lavine&sort=relevancerank template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 516 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. effect of dates nucleus powder on some enginerring properties of clayey soil in comparison to lime yahya k. atemimi, university of babylon, civil engineering department, iraq-hilla. email: eng.yahya.kadum@uobabylon.edu.iq , yehyeaaltemimi@yahoo.com abdulla t. fahad, higher education candidate – university of babylon, civil engineering department, iraq-hilla. email: abdullahtalip9447@gmial.com received on 10 october 2017 accepted on 31 october 2017 published on 15 february 2018 doi: 10.30772/qjes.v10i4.501 abstract: clayey soils are widely spread over the world. the clay soils are used and need to improve it’s engineering properties.therefore, the treatment is considered one of the available solution for this purpose. due to the nature of clay particles a trice plasticity,highly in surface area and the ion exchangaple ...etc. these properties encourage the idea of using pozzolanic materials, particularly the lime as pozzolana source.the alternative source of pozzolan is a metakaolin materials generated from burning the organic materials which are widely available in iraq (i.e. dates nucleus). the dates nuclei is a waste material, so these additives can help in reducing the contamination and improving the environment. in this study, dates nuclei powder (dnp) was used after burning it at 900 o c for one hour and then mixed it with clayey soil in different by weight percentages. hence, four percentages are selected (5%, 7.5%, 10%, and 15%) to study the effect of each addition on the shear strength of the clayey soil and the results are compared with the same soil that treated with lime. many tests were conducted on ( the natural clay, clay-dnp and clay-lime) to evaluate the engineering characteristics and to explore best percentages that can used. curing time (0, 7, 14, 28,90 and 180 days) was used to evaluate the effectiveness of pozzolanic reaction (emerges from dnp-soil mixture) with time. interested results are found, the shear strength was increased to about six folds for 10%-dnp-soil at 180 days of curing. the liquid limit, plasticity index and the maximum dry density decreased in all percentages of dnp-clay mixtures. on the other hand, the shear strength increment for dnp-clay mixture after 180 days of curing is higher than that of lime-clay mixture for same period of curing. forthermore, cbr results increased by six times for 10%dnp-clay mixture for un-soaking conditions, while at soaking conditions, the increase was more than eleven times. the lime addition increase the cbr-value about three and eight times for unsoaking and soaking conditions, respectively. keywords: clay-lime, soil improvement, pozzolana, dates nuclei, cbr. mailto:eng.yahya.kadum@uobabylon.edu.iq mailto:yehyeaaltemimi@yahoo.com mailto:abdullahtalip9447@gmial.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 517 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. introduction the speedy growing in population forced some clients to use bad soils quality in different construction projects due to the scarcity of soil in the urban areas. however, the engineers cannot use this type of soil without treatment before use. therefore, different methods of soil treatment are used and the researchers trying to find the most cheaply and easy methods. the cement and the lime are oldest additive materials that used in soil improvement to increase the soil strength and decrease the compressibility by cementing agents (1). chemical additives have been used in a wide range (i.e. sbr, asphalt …etc) (2). many researchers (i.e. 3, 4) studied soil treatment using lime mixed with another additives to improve the workability and reduce th e total cost. pozzolanic reaction in clayey soil is activated due to the chemical behavior between clay particles and the alumina al2o3.2sio2 leads to produce calcination effect on the soil system and this is the main effect of improvement (5). on the other hand, the physical soil properties (i.e. the plasticity) are strongly influenced by the pozzolanic reaction due to the agglomeration and flocculation effect on the fine soil particles and decrease the surface area (6). many researchers are used several materials (like fibers, bottom ash, rice husk ash …etc) to improve engineering properties of soil, (7,8,1). the waste materials need tens of millions dollars annually to dispose off. therefore, using the waste materials in soil improvement can produce two advantages: first, cleaning the environment with low cost and second is to develop new materials that improve soil properties. today the recycle offal is a new science approach which named green technology. in this study, the date's nuclei powder was used as an additive to improve the shear strength of clayey soil. increasing soil toughness by adding dnp are promising to use it for different layers if used, for example, in a road construction projects. on the other hand, the material used in this study is of no bad health effect on human or animals. 1. materials 1.1. the soil used the soil used in this study is clayey soil and was brought from al-hilla city around university of babylon, the location coordinate is e442509.8, n322819.0 at 2.0 m below ground surface. the soil was then grinded to obtain homogenous soil mass. the soil was classified according to the unified soil classification system astm d2487 (9) and found to be of fat clay with high plasticity (ch). some soil properties are presented in table 1,figure 1 also shows grain size distribution curve. properties soil gs 2.71 color brown ll,% 65 pl,% 30 pi,% 35 % finer<0.002 mm 58 (check it) mdd, g/cm 3 1.56 omc, % 24 table 1: basic geotechnical properties of soil used. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 518 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1.2. lime the lime used in this study is a hydrate lime (ca(oh)2 and it was brought from the nora factory in karbala, iraq. table2 presented the chemical composition of lime used. table 2: chemical composition of lime. compound content,% co2 2.84 cao 69.3 ca(oh)2 91.48 1.3. pozzolana as stated earlier the dates nucleus was used as an additives (pozzolanic materials). the dates nucleus was brought from the factory of date molasses in al-hilla city as a waste product. the materials were grinded by mechanical machine and then burned at 900 o c for one hour (5). the metakaolin powder named (dnp) was mixed with clayey soil at four percentages by dry weight namely: 5%, 7.5%, 10%, and 15%. 2. methodology 2.1. basic properties tests after oven drying of soil at (105 o c-110 o c) for 24 hours and mixing with the dnp at different by weight percentages, many tests were conducted, for example, wet sieving, hydrometer analysis tests in according to astm d421 and d422, respectively. liquid limit and plastic limit tests are also conducted on the soil. claylime mixture and dnp-clay mixture for all percentages were executed according to astm d421-58. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 519 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. maximum dry density and optimum moisture content were determined from the standard proctor test for all soil samples (untreated soil, clay –lime and dnp-clay) according to astm d698-78. 2.2. unconfined compression test (ucs) unconfined compression tests (ucs) were used to evaluate the shear strength of the soil. all soil samples were tested in ucs according to astm d2166, d2166m-16. curing time applied on all tested samples for 7, 14, 28, 56, 90, and 180 days to evaluate the stabilizer effect on long term. only one percent of clay –lime mixture is used for a comparison between the effect of pozzolana in the lime and the pozzolana that was obtained from the dates nucleus. the 3.8% lime by weight was selected to produce lime-clay mixture. this percentage was determined depending on the procedure suggested by u.s. army corps of engineering (10). a 38-mm in diameter by 76-mm height mold was used in this test. the samples extruded from the compaction mold which compacted at maximum dry density (mdd) and optimum moisture content (omc). all samples were coated by plastic bags and then stored in plastic containers till the time of tests. 2.3. california bearing ratio test (cbr) the cylindrical soil specimens had dimensions of 152-mm diameter and 127-mm height. the samples were prepared according to bs 1377: part 4: 1990 clause 7.2.4. using the machine of compaction, the load was applied with a strain rate of (1mm/min). a load cell of 5-kn having steel road (50 mm) diameter was fixed at the top of the frame of device to measure the load applied to the sample. moreover, a surcharge load of 50-n was used as recommended by bs 1377: part 4: 1990: clause 7.4.2.3 , and 7.4.3.4. 3. results and discussion 3.1. effect of dnp on soil gradation and classification the control soil (i.e. untreated soil) was passing from sieve no.200 (i.e. 100% passed #200 sieve) therefore, extended gradation test represented by hydrometer analysis is performed. the results shows that the clay fraction in the soil was 58% and the activity a= 0.61, so the soil was classified as a non-active material. figure 2 shows the plasticity chart and the effect of stabilizers on atterbrag’s limits. it is believed that the soil is agglomerated and the grading transform from clay to silt zone as shown in figure 2 on the other hand, figure 3 showed that adding 10% of dnp lead to produce soil of a lower plasticity than other dnp percentages. however, soil treated with lime experienced more roughness than other samples. the same conclusions were observed by other researchers (11). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 520 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: plasticity chart for all samples used. figure 3: plasticity index results for all samples used. 3.2. effect of dnp on moisture-density relation (compaction) figure 4 shows the results of the compaction tests, a decrease in maximum dry density with the increase in the optimum moisture content for sample treated with lime is observed. on the other hand, the samples treated with dnp shows an increase in the maximum dry density at 5%dnp then a decrease for other percentages. the decrease in maximum dry density with the increase in optimum moisture content can be attributed to the density of stabilizer which was less than the maximum density of the soil used. on the other hand, the small particle size of stabilizer caused an increase in total surface area of the mixture at the short time stage (before chemical reaction). this trend is noticed by other researchers (1,6,8,11). lime al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 521 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: maximum dry density for different samples used. 3.3. effect of dnp on california bearing ratio (cbr) values cbr tests are performed for samples at different conditions. as shown in figure 5, increasing in cbrvalue for both conditions (soaking and un-soaking) with curing time increasing are observed. in the case of un-soaking condition, the cbr-value increased about 1067% (from 3 for untreated soil to 35 for 10%dnp with soil). the soaking condition also shows an increase of about 1700 %( from 1.5 for untreated soil to 27 for 10% dnp with soil). furthermore, the soil treated by lime also shows increasing in cbr of about 767% for un-soaking condition (from 3 for untreated soil to 26 for 3.8%lime with soil). the lime –clay soil mixture in soaking condition show an increase in cbr of about 1233% (from 1.5 to 20 for untreated soil and lime-clay mixture respectively). the results also revealed that the treated specimens by dnp was better than those treated by lime due to the increasing in the strength of about 300% of soil treated by lime to soil treated by dnp as discussed before. the results obtained from cbr tests showed that the (untreated) soil was improved from increasing its strain characteristics. the results refer to modify the untreated soil to use in base and sub-base layer in road construction as recommended by eren and filize 2009. eren and filize 2009 classified the soil according to its cbr number into five zones starting from bad if cbr is between 0 and 3 in the first zone and ends in a very well in zone five if soil has cbr of more than 50. the experimental results in this study shows that the modified specimens by 10%dnp lies in the fourth zone which has cbr of between 20 to 50 as shown in figure 5 the change in shear strength (cbr) for treated specimens can be attributed to pozzolanic reaction that leads to agglomeration and flocculation of the clay particles and change the soil texture from highly plasticity clay to silty soil. the results also showed that the increase in cbr-values for dsp-clay mixture are more than that for the limeclay mixture for similar soaking conditions. the results obtained from this experimental work is correlated with the results presented by amu et al., 2011, and muthyalu et al., 2012. examining the effect of using different chemical stabilizers on cbr, rahman, 1986 found different behavior for the same type of soil. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 522 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: cbr-value results for soaking and un-soaking state of untreated soil, 10%dnp-clay and lime-clay for different curing time. 3.4. effect of dnp on unconfined compressive values figures 6 and 7 show the effect of the percentages of dnp on the strength of soil at different curing ages. the shear strength enhanced as the dnp percentage increased till 10% then started to decrease. the decreasing in shear strength after 10% may be attributed to the chemical reaction between alumina al2o3.2sio2 in clay structure and the pozzolana in dnp. the quantity of alumina in clay particles reacted completely with pozzolana in dnp, therefore, the shear strength began to decrease. on the other hand, the shear strength of lime treated samples was less than that of samples made with other percentages of dnp. this behavior may be attributed to the generated pozzolanic reaction of lime which may less than the quantity of alumina in clay particle, therefore, the soil has low strength. the shear strength also increased to about 577% for 180 days curing period for 10%dnp while the increasing in shear strength was about 244% for lime-clay mixture. also the results showed about 97.5% increasing for 10%dnp more than the same soil treated by lime-clay mixture after 180 days of curing. figure 7 shows the stabilizer agent percentages on shear strength of soil. the samples used in this figure are cured for 180 days. the results showed an increase in shear strength with increasing dnp percent till 10% then began to decrease after that. the increase in shear strength of 10%dnp was about 577% after 180 days curing period while the corresponding increase for lime –clay mixture was 243%. the results showed that the treated soil by dnp was better than the soil treated by lime for the same soil conditions. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 523 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 6: effect of curing time on shear strength of soil treated by dnp and lime. figure 7: effect of stabilizer on soil strength. conclusions from the results discussed earlier, the following conclusions may be drawn: 1the addition of 10% dnp to the clayey soil has a significant effect in improving its shear strength. 2among the four percentages of dnp added to clay, the highest shear strength was achieved at 10%. 3the percentage of dnp added to the clayey soils depended on the percent of clay particles such that the dnp effects increase as the clay particles increase. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 524 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 4using dnp is healthier than use of lime because the dnp is organic materials with no chemical effects on the environments and human. 5the promising results obtained from this study encourage the use of the dnp as a stabilize agent to improve soil strength characteristics in general. references 1. basha e.a., hashim r., mahmud h.b., and muntohar a.s., stabilization of residual soil with rice husk ash and cement” construction and building materials, (2005) vol.19 pp448–453. 2. ahmed f., atemimi y.k, ismail a.m, “evaluation the effects of styrene butadiene rubber addition as a new soil stabilizer on geotechnical properties “egej (2013) vol.18 bund d pp 735-748. 3. kassim k.a, ” the effect of catalyst on soil stabilization by application of lime” university technology malaysia, research vote no.: 78104. (2009). 4. saeed k.a and atemimi y.k, the strength behavior of lime stabilized organic clay soil modified by catalyst additives” journal of babylon university/engineering sciences, (2016) no.(4)/ vol.(24). 5. sabir b.b., wild s. and bai j, metakaoline and calcined clays as pozzolans for concrete, a review” cement and concrete composites” (2001) vol.23,pp441-454. 6. bagheri y., atemimi y.k., ahmad f., ismail m.a.,” soil strength improvement by using a new compound stabilizer” caspian journal of applied sciences research, (2012) vol.2 (aicce'12 & giz' 12), pp. 84-90. 7. alamdari a.s., dabiri r., “ effect of the fibers type on improving the bearing capacity of clayey soils” international journal on technical and physical problems of engineering (ijtpe) (2017), issue 30 volume 9 number 1 pp 43-50. 8. kim y. , and do t.” effect of bottom ash particle size on strength development in composite geomaterial” engineering geology, (2012) vol.139–140 pp. 85–91. 9. astm, “annual book of astm standards. astm international, west conshohocken, pa, www.astm.org., 2005;04-08. 10. krishna r.m, vincent p., kim d., ” family of compaction curves for mechanically modified soils” fhwa/in/jtrp-2005/7. 11. atemimi y.k.,and saeed k.a, “study the effect of date seed powder on the strength of kaolinite clay soil” muthanna journal of engineering and technology (mjet), ,(2016)” pp88-94. 12. eren,s., and filiz m., “comparing the conventional soil stabilization methods to the consolid system used as an alternative admixture matter in isparta darıdere material. construction and building materials, .,(2009). vol. 23, 2473–2480. 13. amu, o.o., and babajide, s.s., “effects of bamboo leaf ash on lime stabilized lateritic soil for highway construction. research journal of applied sciences, engineering and technology, 2011 vol. 3, pp 278-283. 14. muthyalu, v.p., ramu, k. and prasada raju,. g.v.r.,”study on performance of chemically stabilized expansive soil”. international journal of advances in engineering and technology, 2012). vol.2, pp 139148. 15. rahman,m. a., “the potential of some stabilizers for the use of lateritic soil in construction”. building and environmental, 1986vol. 21,pp 57-61. article al-qadisiyah journal for engineering sciences 12 (2019) 144–150 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: aliabbar68@yahoo.com (ali h abbar) https://doi.org/10.30772/qjes.v12i3.609 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. treatment of petroleum refinery wastewater by electrochemical oxidation using graphite anodes sajjad s. jawada and ali h. abbara* a department of chemical engineering, university of al-qadisiyah, al-qadisiyah, iraq. a r t i c l e i n f o article history: received 05 august 2019 received in revised form 23 september 2019 accepted 28 september 2019 keywords: electrochemical oxidation cod removal graphite anode petroleum refinery wastewater phenol a b s t r a c t an electrochemical oxidation method was performed in a batch electrochemical reactor using graphite anodes for treating an effluent obtained from al-diwaniyah petroleum refinery plant. the effective f process parameters like current density (4-20m acm-2), ph (3-9), and nacl concentration (0-3 g/l) on the cod and phenol removal efficiency have been investigated. the results reveal that the best conditions were current density 12 ma cm-2, ph 7, nacl concentration 2 gl-1 at a treatment time of 60 minutes. under best conditions of cod removal efficiency 100% and phenol removal efficiency 99.12% were obtained at current efficiency 33.5% and power consumption 59.9 kwh/kg cod. the anodic oxidation was proven to be efficient for treatment al-diwaniyah petroleum refinery effluent to get effluent with features in agreement with the standard limits for discharge to the environment at a lower cost. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the petroleum refinery industry converts crude oil into its major fractions that can be additionally handled through a series of physical, thermal, and chemical conversion and separation steps into valuable petroleum products such as gasoline, kerosene, liquefied petroleum gas (lpg), fuel oil, diesel fuels, waxes, and lubrication oils [1]. for the purpose of manufacturing the above mentioned products, huge quantities of water are used in refinery processes, especially for distillation, hydro-treating, thermal cracking and catalytic cracking, desalting and cooling systems. petroleum refining process generates wastewater of about 1.6 times the volume of the processed crude oil. the characteristics of petroleum refinery effluents are usually influenced by the production mode, plant configuration and types of oil [2]. generally, the petroleum refinery effluents contain high concentrations of inorganic and organic compounds, chemical additives (surfactants and inhibitors of corrosion), suspended solids, chloride, oil, and grease which added to effluent during the operations of producing petroleum products [3]. this petroleum refinery effluent is usually rich in biological oxygen demand (bod) and chemical oxygen demand (cod) which are responsible for damaging plants, sea, river as well as to surface and groundwater sources [4]. the polluted wastewater generated by refineries contains cod levels of approximately 300–600 mg/l but not limited ; benzene levels of 1–100 mg/l; phenol levels of 20–200 mg/l, heavy metals levels of ( 0.2–10 mg/l pb and 0.1–100 mg/l cr); and other pollutants. . however, concentration of phenol can alter based on the nature of the process [5]. the concentration of phenol in the range 5–25 mg l−1 considers as a toxic material for humans and aquatic life ,therefore the highest allowable limits of phenol in petroleum refinery effluents should be in the range of 0.5 1.0 mg l−1 [6] . a maximum acceptable limit of <0.0005 mg l−1 for phenol in potable drinking water was assigned by the european union (eu), in its 80/778/ec directive [7]. direct discharging of these effluents could result in many environmental pollution issues. approximately 80-90 percent of the water used in the petroleum refinery plants is discharged as wastewater, therefore applying of wastewater treatment is not only to avoid environmental pollution issues but also to reuse of the water again hence another economic benefit for oil refineries [8]. methods used for the treatment of petroleum refinery effluent involve coagulation [9], chemical oxidation [10], advanced oxidation processes http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i sajjad al-kurd and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 144–150 145 [11], adsorption [12], biological approaches [13], membrane treatment [14], and electrochemical techniques [15, 16]. generally, in most these methods, the approach is to transform of pollutants from one medium to another at low efficiency, besides, the choice of any method for treating the effluents of petroleum refinery depends on the composition of these effluents and the final purpose of effluents (discharge or reuse). among them, electrochemical treatment methods have attracted attention due to the numerous advantages gained by these methods such as versatility, selectivity, and cost effectiveness [17]. besides, electrochemical reactions are not depended on the properties of the wastewater and can use any value of current to be supplied to the electrochemical reactor [18]. one of the most important electrochemical methods is the anodic oxidation (also known as electrochemical incineration) which depends on generation of hydroxyl (strong oxidant) on the surface of an electroactive anode then these radicals attack the organic compounds existing in wastewaters and transform them to water and co2 [19]. in contrast to chemical and advanced oxidation processes, like fenton reaction which based on using iron ions and hydrogen peroxide as reagents in its chemical mechanism, as well as photo-fenton process which used fenton reagents with ultra violet (uv) radiation to generate the hydroxyl radical, anodic oxidations do not need to use or stored of dangerous substances, in addition to easiness of scale-up. other benefits involve low labour requirements since the processes are fairly simple and could be automatized. the method gives environmental advantages, as it uses electron as the main reagent [20]. during an anodic oxidation process, organic compounds can be incinerated by direct or indirect oxidation. in a direct process, the pollutants are first adsorbed on the surface of an anode and then undergo an oxidation reaction via transfer of electrons directly. in this case, the material of the electrode used for oxidation of organic compounds is the most important variables to be taken into account for obtaining high rates of electro-oxidation. the oxidation powers of many types of anodes like boron-doped diamond (bdd), dimensionally stable anode (dsa), lead dioxide (pbo2), and doped-sno2 have been investigated for the direct oxidation of many organic substances such as phenol [21–24]. among these electrodes, bdd is the best anodic material for degradation of organic compounds, because it has a wide potential window for discharging of water and its ability to generate weakly adsorbed hydroxyl radicals which giving rapid and efficient anodic oxidation [19]. besides, bdd electrode has higher stability and chemical-resistant than other anodes which enables it to be used for a long time justifying its high cost. at the indirect processes, strong oxidants such as hypochlorite/chlorine, hydrogen peroxide, and ozone are generated by anodic oxidation then reacted with the organic compounds in the bulk solution [25, 26]. chloride is particularly engaging for use in the indirect oxidation due to the presence of chloride salts in wastewaters [27]. furthermore, previous works confirmed the role of active chlorine in the anodic oxidation of dyes and different organic substances [28]. adding of chloride ions to the effluents was found by many researchers to be contributed in minimizing the energy consumption because of the enhancing in the current efficiency and oxidation kinetics as well as reducing of cell potential [29,30]. in the present work, indirect anodic oxidation process was used to remove chemical oxygen demand (cod) and phenol from petroleum refinery wastewater resulted from al-diwaniyah petroleum refinery plant using a batch electrochemical reactor in which the effect of different parameters such as current density, ph, and nacl concentration were investigated. 2experimental work petroleum refinery effluent samples were provided by al-diwaniyah petroleum refinery plant. sample (20l) was collected from the feed tank to the biological treatment unit and stored in closed containers at temperature 4 ºc until use. characterization of this sample is shown in table 1. besides the properties of effluent taken from the settling tank of the final stage of the biological treatment that was measured by petroleum refinery plant administration with the permissible limit were mentioned in this table for comparison table 1. characteristics of the effluents in al-diwaniyah petroleum refinery plant. test feed tank sample settling tank* permissible limit* cod(mg/l) 160 65 100 ph 7.8 7.5 (6-9.5) t.d.s 1710 1680 ---- cl (mg/l) 931 119 100 so4(mg/l) 560 400 400 turb. 5.17 6.44 41.3 cond. (µs/cm) 3320 ------- phenol(mg/l) 0.17 (0.01-0.05) 0.06 *provided by al-diwaniyah petroleum refinery plant administration figure 1. the electrochemical system: 1) cell body, 2) cathode (stainless steel), 3) anode(graphite), 4)power supply, 5)ammeter, 6)voltmeter, 7)ph-meter, 8) ph-probe, 9) discharge valve, 10)water bath. nomenclature cod chemical oxidation demand ( (mg l−1) f faraday's constant (96487 c/mol) tds total dissolved solid ((mg l−1) v effluent volume (l) bod biological oxygen demand (mg l−1) δc cod difference values (g/l) dsa dimensionally stable anode i current (a) cond conductivity (µs/cm) t electrolysis time (s) ci initial concentration (mg l −1) ec electrical energy consumption (kwh/kg) cf final concentration (mg l −1) u applied cell voltage (volt) re removal efficiency (%) codi initial chemical oxygen demand (mg l −1) ce current efficiency (%) codf final chemical oxygen demand (mg l −1) 146 sajjad al-kurd and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 144–150 a rectangular perspex glass lab-scale batch electrochemical reactor was used for the anodic oxidation treatment experiments. it has inside dimensions (120 mm width x 120 mm length x 120 mm height) and active electrolyte volume of 1.25 l, provided with perspex cover of external dimensions (150 mm × 150 mm × 28 mm thickness). the cover contains slits for electrodes fixation and holes for inserting the probe of ph-meter and conductivity meter. a parallel plate configuration was adopted for the electrochemical reactor were three stainless steel plate cathodes (130 mm × 80 mm × 3 mm (thickness)) and two graphite anodes (130 mm × 80 mm × 3 mm (thickness)) were used. the distance between cathode and anode was fixed at15 mm. a digital direct current power supply (0–30 v, 0–5 a) type (uni-t, utp3315pf) was used to provide constant current during each experiment. in each run, 1.25l solution was agitated using magnetic stirrer to achieve the proper mixing conditions then transfer to inside the cell. all the experiments were carried out at constant temperature 30 ºc using water bath (memmert, type: wnb22, germany). fig.1 shows the schematic diagram of the electrochemical oxidation experimental setup supported by the required information. the electrolyte ph was measured using a digital ph meter (hnna instrument inc.ph211, romania) and the electrolyte acidity was adjusted by using hcl or naoh for the appropriate experimental condition. conductivity and tds were measured by using (hm digital inc. model com-100, korea). the samples were taken and analyzed to determine the cod and phenol concentration every 10 minutes of the electrolysis time. the concentration of total organic compounds in the effluent is expressed in terms of chemical oxygen demand (cod). amount of cod in petroleum refinery effluents was measured by taken a sample (2ml) of effluent digested with an oxidizing agent (k2cr2o7) for 120 minutes at 150 °c in a cod thermos-reactor (rd125, lovibond). the digested sample was cooled down to room temperature then analyzed in a spectrophotometer (md200, lovibond). phenol was measured by using method 8047 assigned by hach company/hach lange gmbh, usa [31]. measuring of phenol concentration and cod were achieved three times and the average values were taken in this work. the removal efficiency of cod and phenol were evaluated based on eq. (1), where ci is the initial concentration (mg l −1) and cf is the final concentration (mg l−1) [32]: 𝑅𝐸% = 𝐶𝑖−𝐶𝑓 𝐶𝑖 × 100 (1) the current efficiency refers to the portion of the total current used for the specified reaction. it was calculated with the theoretical value that 1 molar electrons (96485 coulombs charge) would be transferred via oxidizing 8 g cod. assuming all the cod removal was due to the electrochemical oxidation, then by counting the charges transferred and monitoring the cod removal in the solution, the current efficiency(ce%) could be estimated from equation [33]: 𝐶𝐸% = 𝐹.𝑉 .𝛥𝐶 8𝐼.𝑡 × 100 (2) where f is faraday's constant (96487 c/mol), v is the effluent volume in (l), δc is the difference in the cod values in (g/l), i is the current in (a), 8 is a dimensional factor for unit consistency, it is the oxygen equivalent mass {32 g of o2 /4 mol of electrons} (g /mol), and t is the electrolysis time (s). the electrical energy consumption (ec) is the amount of energy consumed in the oxidation process for a kg of cod removed. ec in (kwh/kg) can be calculated by eq. (3) [34]: 𝐸𝐶 = 𝑈.𝐼.𝑡 ×1000 (𝐶𝑂𝐷𝑖−𝐶𝑂𝐷𝑓) 𝑉 (3) where ec is the energy consumption (kwh/kg cod), u is the applied cell voltage (volt),i is the current (a),t is the electrolysis time (h), codi and codf are the initial and final chemical oxygen demand (mg/l),and v is the effluent volume (l). 3. results and discussion 3.1 effect of current density figure 2 shows the abatement of cod with time at different current densities using effluent containing nacl with a concentration of 2g/l and adjusted acidity initially at ph 7. it was clear that increasing current density leads to decrease the final cod value of the effluent. it was observed that the efficiency of degradation is higher at the initial stage of anodic oxidation; however, it then proceeded gradually as anodic oxidation continues. this behavior can be interpreted as the concentration of organic pollutants is high at the initial period of electrolysis so the electrochemical reaction is under current-limited control where nearly most the applied current is used to oxidize the organic compounds by the generated ocl-. however, the concentration of organic pollutants is reduced gradually during the electrolysis leading to make the oxidation process under mass transport control, hence a slight increase in degradation efficiency is occurred due to the taken place of side reactions, such as oxygen evolution [35] .table 2 shows the removal efficiency of cod at different current densities where complete removal of cod was obtained at current density equal or higher than 12macm-2 at electrolysis time of 60 min. the effect of current density on phenol removal efficiency is also reported in table 2 where increasing current density results in increasing the removal efficiency of phenol. it is interesting to note that final phenol concentration is 0.0015 at current density of 12macm-2 which is lower than the permitted level and became lowest at higher current densities. an increase in current density would increase electricity consumption. using current density higher than 12macm-2 resulted in increasing power consumption higher than (60kwh/kg cod) ,therefore it is the best to choose this current density for further investigation. similar observations were found in previous studies [19, 34, 36, 37]. figure 2. cod abatement with time at different current density. ph=7, [nacl] = 2g/l, temp. = 30◦c. figure 3 illustrates how the ph is affected by current density through the operation where ph decreased for the first 30 min then started to increase for further electrolysis time. similar trend was observed by souza and sajjad al-kurd and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 144–150 147 ruotolo [19] in the electrochemical treatment of an oil refinery effluent using boron-doped diamond anodes, where the ph started to decrease initially from a ph value of 9.5 then increased after (2 hrs.) of electrolysis time suggesting the responsibility of the intermediate compounds that generated during the electrolysis for the change in ph . figure 3 ph profile with time at different current density 3.2 effect of nacl concentration figure 4 displays the abatement of cod with time at different nacl concentration using effluent with acidity adjusted initially to ph 7. it was clear that increasing nacl concentration leads to a decrease in the final cod value of the effluent. table 3 reveals this behavior where the effect of nacl concentration on the removal efficiency of cod and phenol are reported. it can be seen that increasing of sodium chloride concentration from 0 to 3 g/l results in increasing of cod removal efficiency from 91.88 to 96.88% at abatement time of 30min, while a complete cod removal was obtained with and without addition of nacl at various concentrations at abatement time of 60min. this is interesting results which confirm that chlorine ions which originally existing in the solution have the ability to degrade the pollutants even at low concentration. however, the final concertation of phenol is higher than 0.0015 at nacl concentration lower than 2gl-1. it is preferred to conduct further experiments at nacl concentration of 2 g/l in which a complete removal of cod at the required level of phenol concentration discharge was achieved. besides a negligible decrease in the energy consumption was observed at nacl concentration higher than 2gl-1 also using higher concentration of nacl may favor producing chlorinated organic compounds not destroyed by the anodic oxidation as proved by previous studies [38]. similar trends were observed by britto-costa and ruotolo [38] in the electrooxidation of phenol using bdd or dsa electrodes where cod removal increases with addition of nacl. souza and ruotolo [19] studied the electrochemical oxidation of oil refinery effluent using boron-doped diamond anodes. they found that addition of 450 mg/l of nacl gives higher removal of cod in comparison with no addition of nacl. ibrahim et al [34] investigated the electrochemical oxidation treatment of petroleum refinery effluent and found that increasing nacl concentration gives higher abatement of cod using titanium anode. figure 5 shows how the ph affected by nacl concentration through the operation where ph is decreased for the first 30 min then started to increase for further electrolysis time. santos et al. [37] found a similar trend in the treatment of an effluent from petroleum industry using ti/ruo2 anode where the ph decreases for time period shorter than 30min then start to increase after (30 min.) interpreting their results by the formation of low molecular weight of acid compounds like oxalic acid during the first period (30min.) then hypochlorite become the predominating species after that period. table 2. effect of current density on cod and phenol removal efficiency current density ma/cm2 phenol conc. (mg/l) phenol re% cod removal (%) ce (%) ec ( kwh/kg ) ci cf at 60 min at 30 min at 60 min 4 0.17 0.003 98.23 86.88 93.75 78.52 16.89 8 0.17 0.0016 99.05 92.50 97.50 40.20 41.15 12 0.17 0.0015 99.12 95.00 100 33.50 59.90 16 0.17 0.0005 99.70 96.88 100 25.13 87.14 20 0.17 0.0005 99.70 98.75 100 25.13 103.48 table 3. effect of nacl concentration on cod and phenol removal efficiency nacl conc. (g/l) initial cond. µs/cm phenol conc.(mg/l) phenol re% cod removal (%) ce (%) ec ( kwh/kg ) ci cf at 60 min at 30 min at 60 min 0 3320 0.17 0.002 98.82 91.88 100 26.8 93.33 1 4900 0.17 0.002 98.82 93.75 100 33.5 62.48 2 6510 0.17 0.0015 99.12 95.00 100 33.5 59.9 3 7900 0.17 0.0003 99.82 96.88 100 33.5 57 148 sajjad al-kurd and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 144–150 figure 4. cod abatement with time at different nacl concentrations. i=12macm-2, ph=7, temp. = 30◦c. figure 5 ph profile with time at different nacl concentrations 3.3 effect of ph figure 6 displays the abatement of cod with time at different ph using effluent containing nacl at concentration of 2g/l. it was clear that decreasing ph leads to decrease the final cod value of the effluent. the effect of ph on the removal efficiency of cod and phenol was studied and shown in table 4. it was observed that the initial ph has a substantial impact on the cod and phenol removal efficiency. the maximum removal efficiency of cod and phenol was occurred at ph equal or lower than 7. similar observations were made by fil et al [39] who studied the treatment of oistachio processing industry wastewater by anodic oxidation using graphite anode in the presence of nacl where higher cod removal was observed at acidic solutions. ibrahim et al [34] in their study found that neutral conditions give better results than alkaline medium with respect to cod removal. this behavior can be interpreted as the anodic oxidation generally gives better results in acidic or neutral conditions than the basic conditions when chlorine ions existing in the electrolytic process where formation hypochlorous which is a more powerful oxidant than hypochlorite has happened. previous studies approved that at alkaline conditions the active chlorine exists in the form of hypochlorite which is a less strong oxidant towards organic species in regarding to hypochlorous acid that is the main species present at ph approached to 3 [39,40]. on the other hand, the final concentration of phenol is higher than 0.0015 as ph increased and became more alkaline. the ph profile with time at different initial ph is illustrated in figure 7 where the ph is decreased for the first 30 min then started to increase for further electrolysis time. similar observations were found by previous works [19, 37]. using an initial ph of 7 is recommended for the environment conditions since starting with ph=3 results in discharging effluent with ph lower than 6 as shown in figure 7. figure 6. cod abatement with time at different ph. i=12macm-2, [nacl] = 2g/l, temp. = 30◦c. table 4. effect of ph on cod and phenol removal efficiency ph phenol conc. (mg/l) phenol re% cod removal (%) ce (%) ec ( kwh/kg ) ci cf at 60 min at 30 min at 60 min 9 0.17 0.0025 98.53 90.63 97.5 27.22 72.03 7 0.17 0.0015 99.12 95 100 33.5 59.9 3 0.17 0.0013 99.23 97.5 100 33.5 56.61 figure 7 ph profile with time at different initial ph sajjad al-kurd and ali h. abbar /al-qadisiyah journal for engineering sciences 12 (2019) 144–150 149 4. conclusions anodic oxidation using graphite anodes seems to be more efficient method for treatment of wastewater produced from al-diwaniyah petroleum refinery plant as confirmed by the present work. increase in the current density, nacl concentration resulted in an increase of cod and phenol removal efficiencies, while increasing the initial ph higher than 7 resulted in decreasing of cod and phenol removal efficiencies. based on the results of this work, current density has a significant effect on the cod and phenol removal than the other variables. by adjusting initial ph to a value of 7 , adding nacl at concentration of 2g/l and applying current density of 12 ma cm-2 for an interval of time equal to 60 min, a complete removal of cod(100%) with phenol removal efficiency of 99.12% were achieved in which values of current efficiency(33.5%) and energy consumption(59.9kwh/kg ) were observed. the energy consumption in the present work is relatively lower than that reported in previous works in the field of petroleum refinery effluent treatment using other anodes [19, 34, 37]. acknowledgements the authors appreciate the unlimited help and technical assistance provided by the staff of chemical engineering department, college of engineering university of al-qadisiyah. references [1] y. yavuz, a.s. koparal, u.b. ogutveren, treatment of petroleum refinery wastewater by electrochemical methods, desalination, 258 (2010) 201–205. 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[40] o. scialdone, s. randazzo, a. galia, g. silvestri, electrochemical oxidation of organics in water: role of operative parameters in the absence and in the presence of nacl, water res. , 43 (2009) 2260–2272. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewj-15rdu8djahw-qeeahfgbbl0qfjaaegqibrac&url=https%3a%2f%2fwww.hach.com%2fasset-get.download-en.jsa%3fcode%3d55864&usg=aovvaw1_zrxcmsljbp_0wlv5b5pb https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewj-15rdu8djahw-qeeahfgbbl0qfjaaegqibrac&url=https%3a%2f%2fwww.hach.com%2fasset-get.download-en.jsa%3fcode%3d55864&usg=aovvaw1_zrxcmsljbp_0wlv5b5pb al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٣ effect of adding cement and silica fume with cement on compaction properties and shear strength of clayey soil mohammed khachi al-zairjawi, civil eng. dept., al-mustansiriya university abstract this paper describes a study on the effect of adding cement and silica fume with cement on the engineering properties (compaction and shear strength) of the clayey soil. inorganic clay with low plasticity was used in this study as a natural soil. a series of laboratory experiments have been implemented and varieties of samples were made by mixing both cement and silica fume with cement . four different percentages of cement (2%, 4%, 6% and 8%) and three different percentages of silica fume (2%, 4% and 6%)were used as a stabilization materials . test results show that adding cement and silica fume with cement decreases the maximum dry density and increases the optimum moisture content. the unconfined compressive strength of the soil was found to increase significantly with increase in the cement and silica fume with cement content especially after a long curing period. �)اص ا��ص و-��و-� ا��m ����ب �� o%ا��� pم(���qوا����� o%ا��� ���hإ ��st> �-���ا� � ا�vر��uوي.�� ��� آ��� ا�,%��� ا��u-�� ا����%?��� ا���4 ا:��#0 و)��ر ا�*��pa �c ا:��#0 �� ا���اص ا�?��3#%�fإ ��-./ ا��z( ه6ا ا���$ �=i درا�aو��aا��ص و ( &(� �� �#�� . ا�&����' &(� � ه6ا ا���$ آ% da3ا� /7 ا����k dي ذو �3و��m ��k h�' .� �&?lا�g7 أ&/ &��� h&a ا��e�4&�ت ا����*&� � / 7 ��o��( �? آ& h&a ا:�&�#0 و )�&�ر ا�&*��p&a �c ا:�&�0# �i ا�#��ذج ا��a �� . 0#�&�:ا h&a &e� �a t*&� p&(أر)٢% ، ha )��ر ا�*����c %) ٨و % ٦، %٤e� �a t*� �8 &d %) ٦و% ٤، % ٢(و-�-a آ��اد �?a3ا� ا�# &�nl )�#&0 أن إ ./7 ا�%�&f &�ى ا��'�)&�a 7�&k �&% �&f&�دة وا�0 ز&� وأ &(� ا��;�&� ��&%�uا� &%�8c0 ا�&��k 0#��:ا pa �c��*ا:��#0 و)��ر ا� ha آ 8a,ا . p&a �c��*&ر ا��&�( q�6&ا:�&�#0 وآ h&a &آ %�&fإ � p&a ا�r�&�دة %&�&fا���&=�ر ازدادت )&=�رة وا ��k zا�� aو��a �' u���a ة� % 3# �4�=� ا:��0# ��. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٤ introduction soil stabilization has been used in nearly every type of soil engineering problem. when the geotechnical engineers are faced with clayey soils, the engineering properties of those soils may need to be improved to make them suitable for construction. cement is used as soil stabilizing agent especially for road construction, such as for sub-base, air port runways and earth dams(van impe 1989) (1) . silica fume is a mineral admixture, composed of submicron particles of silica dioxide, manufactured as a coproduct from the production of silicon and ferrosilicon metal. (mc kennon et al.1944) (2) found that the addition of silica fume plays a very important role in improvement of chemical properties of lime treated soil, especially sulfate bearing soils. the effects of engineering properties of clayey soil when blended with cement and silica fume with cement are the main focus of this research laboratory tests 1 liquid limit cone pentrometer apparatus is used for measuring liquid limit of natural soil and the procedure according to bs 1377-1975, test 2(a) is adopted for this test. venkatappa rao and rekhi(1977) (3) stated that the cone pentrometer has widely used with success for the determination of the liquid limit due to its simplicity and less human error. 2 plastic limit the plastic limit tests are conducted according to the (bs 1377-1977, test 3) 3 the specific gravity the specific gravity of specimens is determined in accordance to the (bs1377-1977) using density bottle of 50 ml. capacity. 4 compaction test compaction tests are conducted using standard compaction test( 2.5 kg rammer method) as reported in the (bs 1377-1977, test 12). 5 unconfined compressive strength test unconfined compressive strength tests are performed to study the effect of adding the cement and silica fume with cement on the shear strength of clayey soil, as reported in the (bs 1377 1977, test 20). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٥ materials used 1 natural soil the soil that used in this study was from al-taji city (north of baghdad). table (1) shows the properties of this soil. according to uscs (unified soil classification system), the soil has been classified as cl (inorganic clay of low plasticity. 2 cement cement have been established as a deep solidification technique via deep mixing to create cement columns, using powder or slurry placed into pre-formed holes to create cement piles, or via cement slurry pressure injection into intact soils (boardman,2001) (4) . any type of cement can be used to stabilization soil, but the most commonly used is the ordinary portland cement(janz and johansson, 2002) (5) , therefore this type of cement was used in this study. (ingles and metcalf, 1972) (6) showed that, strength increases linearly with increasing cement content, curing age, temperature and density. alameri (2002) (7) concluded that the maximum dry density is observed to have marginal reduction with the increase in the cement content. 3 silica fume silica fume is a by – product in manufactured of silicon and ferrosilicon alloys. nearly 100000 tons of silica fume are produced each year on the world. silica fume is used in concrete, ceramics and rubber. when added to concrete, silica fume acts as both a filler, improving the physical structure by a occupying the space between the cement particles and as a pozzolan reacting chemically to important far greater strength and durability to concrete( ganjian, 1977) (8) . (u.s army corps of engineering, 1999) (9) , showed that silica fume in concrete is usually used at a rate of 10 to 20 percentage by weight of cement and the silica fume improves the bond between the paste and the aggregate. asskar and baghherpour(2007) (10) , showed that the addition of silica fume has no much effect of plasticity index of lime mixture. samples preparation the natural soil used in this study was dried, then mixed with different percentage of cement and silica fume with cement. four different percentages of cement (2%, 4%, 6% and 8%)and three different percentages of silica fume (2%, 4% and 6%) were used as a stabilization materials. the percentages were calculated in terms of dry weight of the soil. the samples of the unconfined compressive strength tests were put in two nylon bags and were caring until reaching to desired age (1 hour, 1 day, 7 days and 28 days) ,all these samples were performed with optimum moisture content and to a maximum dry density of the soil. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٦ results and discussion 1 compaction characteristic a series of tests are conducted to study the effect of adding cement and silica fume with cement on the compaction characteristic (optimum moisture content and maximum dry unit weight) of the clayey soil. figures (1) and (2) show that adding cement slightly increased the optimum moisture content and diminish a small amount of the maximum dry density correspond to increasing of cement percentage. the same characteristics can be also observed when silica fume was blended with cement, as illustrated in figures (3) and (4). the increasing in the optimum moisture content is probably a consequence of two reasons: the first is, the additional waster held with the flocculated soil structure resulting from cement and silica fume interactions, and the other reason is, exceeding water absorption by cement and silica fume as a result of its porous properties, as reporting in zhang et al.(1996) (11) . rahman(1987) (12) , revealed on opinion that change in dry density occurs because of both the particles size and specific gravity of the soil and stabilizer. 2 unconfined compressive strength studies were carried out to examine the effect of cement and silica fume with cement and curing period on the unconfined compressive strength of the clayey soil. figure (5) shows the plot of the unconfined compressive strength with cement content at different period of curing. as shown in this figure, the increasing in the cement content increased the unconfined compressive strength of the soil. similarly higher strength was obtained from samples that had been cured for 28 days compared with 1 hour, 1 day and 7 days. bergado(1996) (13 ) showed that pozzolanic reaction can continue for mouths or even years after mixing, resulting in the increased in strength of cement stabilized clay with increase in curing time. influence of adding silica fume with cement on the unconfined compressive strength for samples after 1 hour, 1 day, 7 days and 28 days curing time are shown in figure(6). as illustrated in this figure, the increase in silica fume improved the unconfined compressive strength in all mixtures, and the ratio of increasing between the unconfined compressive strength of the natural soil and stabilized soil(8% cement, 6% silica fume and 28 days curing period) was 3.25. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٧ conclusions according to the results obtained in this study, the following conclusions are down: 1adding cement and silica fume with cement decreases the maximum dry density and increases the optimum moisture content of the soil. 2the unconfined compressive strength of the soil was found increase significantly with increase in cement content especially after a long curing period. 3adding silica fume with cement increases the unconfined compressive strength of the soil. adding 6% silica fume to 8% cement (28 days curing period) increase the unconfined compressive strength of the soil from 80 kpa to 190 kpa. references 1van impe, w.f.(1989)" soil improvement techniques and their evolution". balkema. 2mc kennon, j.t., hains, norman l. and hoffman, c. " method for stabilizing clay bearing soils by addition of silica and lime" patent cooperation treaty(pct), patent classification: c09k 17/00, publication number: wo 94/06884. 3-venkatappa rao, g. and rakhi, t.s.,(19977)" physico -chemical mechanism governing the plasticity behaviors of soils," indian geotechnical journal, vol.7, no.4, pp.261-282. 4boardman, d.i., glending, s. and rogers, c.d.f(2001)" development od stabilization and solidification in lime-clay mixes" geotechnique 50,no 6, pp. 533-543. 5janz, m. and johansson, s.e. (2002)" the function of different binding agents in deep stabilization." swedish deep stabilization research center, linkoping: sgi. 9. 6ingles,o.g. and metcalf, j.b.(1972)" soil stabilization" butter worth pty, limited, australia. 7alameri, a.f.(2002)"effect of cement addition on the consolidation properties of saline soils." m. sc. thesis, civil engineering department baghdad university, iraq. 8ganjian,e.(1997)" mechanical and physical properties of iranian produced microsilica." proceeding of the international seminar on the use of microsilica in concrete, iran, pp. 197-214 9-u.s.army corps of engineers(1999):use of waste materials in pavement construction" etl. 1110-3-503. 10asskar, j.c and bagherpour, i. (2007)" stabilization of fine grained soils by adding microsilica and lime or microsilica and cement" electronic journal of geotechnical engineering, vol. 13 11zhang, m.h., lastra, r. and malhotra, v.m.(1996)" rice husk ash paste and concrete" cement and concrete research, vol. 26(6), pp. 963-9777. 12 rahman, m.a.(1987) " effect of cementrice husk ash mixture on the geotechnical properties of the lateritic soils" journal of soils and foundations, vol. 27(2), pp. 61-65. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٨ 13bergado, d>t> (1996)" soil compaction and soil stabilization by admixtures" proceeding of seminar on grout improvement application to indonesian soft soils, indonesia: jakarta, pp. 23-26. table(1): properties of natural soil d max g/cm 3 .  omc % pi % pl % ll % gs % sand passing # 200 1.73 ١٨ 19 17 36 2.69 6 94 figure (1): effect of cement content on the optimum moisture content of clayey soil figure (2): effect of cement content on the maximum dry density of clayey soil 0 2 4 6 8 10 cement content(%) 16 18 20 22 o p ti m u m m o is tu re c o n te n t( % ) 0 2 4 6 8 cement content(%) 1.55 1.60 1.65 1.70 1.75 m a x im u m d r y d e n si ty (g /c m )3 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٩ figure(3): effect of silica fume content on the optimum moisture content of clayey soil containing different cement content figure (4): effect of silica fume content on the maximum dry density of clayey soil containing different cement content 0 2 4 6 8 silica fume content(%) 1.52 1.56 1.60 1.64 m a x im u m d r y d e n si ty ( g /c m )3 cement content 2% cement 4% cement 6% cement 8% cement 0 2 4 6 8 silica fume content(%) 19 20 21 22 23 o p ti m u m m o is tu r e c o n te n t( % ) cement content 2% cement 4% cement 6% cement 8% cement al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٠ figure (5): effect of cement content and curing period on the unconfined compressive strength of clayey soil. 0 2 4 6 8 silica fume content(%) 80 90 100 110 120 130 u n c o n fi n e d c o m p r e ss iv e s tr e n g th (k p a ) curing period 1 hour 1 day 7 day 28 day 2% cement 0 2 4 6 8 silica fume content(%) 80 90 100 110 120 130 u n c o n fi n e d c o m p r e ss iv e s tr e n g th (k p a ) curing period 1 hour 1 day 7 day 28 day 4% cement 0 4 8 cement content(%) 80 100 120 140 160 180 u n c o n fi n e d c o m p r e ss iv e s tr e n g th (k p a ) curing period 1 hour 1 day 7 day 28 day al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦١ figure (6): the unconfined compressive strength versus silica fume content at different cement content and curing period 0 2 4 6 8 silica fume content(%) 80 100 120 140 160 u n c o n fi n e d c o m p r e ss iv e s tr e n g th (k p a ) curing period 1 hour 1 day 7 day 28 day 6% cement 0 2 4 6 8 silica fume content(%) 80 120 160 200 u n c o n fi n e d c o m p r e ss iv e s tr e n g th (k p a ) curing period 1 hour 1 day 7 day 28 day 8% cement article al-qadisiyah journal for engineering sciences 13 (2020) 125–135 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: : ali.abbar@qu.edu.iq ( ali h. abbar) https://doi.org/10.30772/qjes.v13i2.652 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. optimization of process parameters for the electrochemical oxidation treatment of petroleum refinery wastewater using porous graphite anode ahmad s. fahim a, ali h. abbar a* a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq. a r t i c l e i n f o article history: received 01 april 2020 received in revised form 17 may 2020 accepted 25 june 2020 keywords: petroleum refinery wastewater indirect oxidation porous graphite response surface methodology cod removal a b s t r a c t the present paper deals with the electrochemical treatment of wastewaters generated from al-diwaniyah petroleum refinery plant in a batch electrochemical reactor using stainless steel cathode and porous graphite anode. effects of operating parameters such as current density (5-25 ma/cm2), ph (3-9), addition of nacl (0-2g/l), and time (20–60 min) on the removal efficiency of chemical oxygen demand (cod) were investigated. the results revealed that both ph and nacl addition have the main effect on the cod removal efficiency confirming that the system was governed by reaction conditions in the bulk of solution not upon the electro oxidation of chloride ion on the surface of the electrode. parametric optimization was carried out using response surface methodology (rsm) combined with box–behnken design (bbd) to maximize the removal of cod. under optimized operating conditions of initial ph: 3, current density = 25 ma/cm2, nacl conc. = 2 g/l, and time = 60 min, the removal efficiency of cod was found to be 98.16% with energy consumption of 9.85 kwh/kgcod which is relatively lower than the previous works. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction in petroleum refinery process, crude oil converts into its main fractions using physical, thermal, and chemical separation processes then these fractions are further processed through a series of other conversion and separation steps into final petroleum products such as gasoline, liquefied petroleum gas (lpg), diesel fuels, kerosene, lubrication oils, and many others. for the purpose of getting these products, a large quantity of fresh water is utilized for refinery processes, mainly for hydro-treating, distillation, desalting, and cooling systems [1]. about 80-90 % of the water used in petroleum refinery process converts into wastewater. diya’uddeen et al. [2] identified that the quantity (as volume) of the effluents generated from petroleum refinery in the course of crude oil processing is 0.4–0.6 times the quantity (as volume) of the crude oil processed. the composition of generated wastewaters depends on the type of oils, mode of manufacturing, and process configuration. the polluted wastewater generated by refineries contain cod levels of nearly 300–600 mg/l; phenol concentration of 20–200 mg/l; benzene concentration of 1– 100 mg/l; heavy metals with concentrations as chrome (0.1–100 mg/l), as lead (0.2–10 mg/l), and other pollutants [3]. direct disposal of these wastewaters could lead to essential pollution problems for the environment http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 126 ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 due to the high content of polycyclic aromatic compounds that have very toxic effects on the environment since they have the ability to exist in the environment for a long time. therefore, these effluents should be treated before discharging [4]. the common treatment method of wastewater generated from refinery plants is based on mechanical and physicochemical methods in addition to further processing by biological treatment in an integrated activated-sludge treatment unit. several other treatment methods were studied by the researchers including photocatalytic oxidation [5], wet oxidation [6], photodegradation [7], catalytic vacuum distillation [8], coagulation–flocculation [9], fenton oxidation [10], adsorption [11], membrane [12], membrane bioreactor [13], and chemical precipitation [14]. generally speaking, the main ideas of most of these methods are the conversion of pollutants from one medium to another with low efficiency [2]. electrochemical oxidation (eo) treatment as a competitive technology has been used for treating different kinds of industrial wastewaters like pulp and paper plants, distillery, tannery, and textile industry. eo destruction of wastewaters containing phenolic compounds, such as dyes, poly-aromatic organic compounds, arsenic, and sulfidic spent caustic is also reported in the literature [15-19]. the electrochemical oxidation method offers a clean and powerful method for the mineralization of organic contaminants in water. great attention for this method has been attracted because of the several distinguishing benefits such as versatility, safety, selectivity, energy efficiency, cost effectiveness, amenability to automation, and environmental compatibility since the main reagent used is the electron [2022]. in contrast to chemical or photochemical oxidation, electrochemical oxidation does not need to utilize or store dangerous substances and its scale-up is more feasible [22]. during an electrochemical oxidation process, contaminants can be degraded by direct or indirect oxidation routes. in a direct route, the organic pollutants are first adsorbed on the surface of the anode and then destroyed by direct electron transfer. the indirect route includes the generation of strong oxidants electrochemically like hypochlorite/chlorine, hydrogen peroxide, and ozone, which react with the organic pollutants in the bulk solution [23]. chloride is specifically attractive for using in the indirect oxidation due to the usually existing of chloride salts in wastewaters [24]. furthermore, the role of active chlorine in the destruction of dyes and other organic compounds has been extensively studied by researchers in literature [25, 26]. adding chloride ions to the effluent will also lead to minimize the energy consumption because of the improving in current efficiency and oxidation kinetics as well as decreasing the cell potential [27]. the performance of electrochemical oxidation processes in the destruction of contaminants is recognized by the complex interaction of different factors that may be optimized to get an economical and effective process. the main factors that determine the performance of an electrochemical oxidation process are: current density; electrode potential; mass transport regime; current distribution; conductivity; ph; cell design; electrode materials; and types of the contaminants. [28]. hence, the electrochemical oxidation process seems to be a complex process due to the many variables affecting the mechanism of this process. in this case, the application of an experimental design method is essential to reduce the number of experiments with a better combination of the input factors. statistical design decreases the process variability as well as the time required for trial and error experiments [29]. rsm is a substantial subject in the statistical design of experiments. it had been effectively applied in numerous processes for wastewater treatment like adsorption [30], chlorine disinfection [31], electrocoagulation [32], and fenton-related process [33]. it is composed of a collection of mathematical and statistical approaches that could be used efficiently to analyze and model of many problems in which a response of interest is influenced by different parameters. the target of rsm is to evaluate the relative influence of different affecting parameters and finally obtain the best operating conditions by optimizing this response [34]. in spite of the electrochemical oxidation processes have plentiful applications for the treatment of several kinds of wastewater; their use for the treatment of wastewater generated from petroleum refinery plants is scarce in the literature. in previous works, the material of electrode is the key factor that determines the performance of an electrochemical oxidation process for the treatment of petroleum refinery effluents because of the material of electrode could change the mechanism of oxidation and anodic reactions. for example, yavuz et al., [35] investigated the treatment of petroleum refinery wastewaters using direct and indirect electrochemical oxidation by two types of anodes; boron doped diamond (bdd), and ruthenium mixed metal oxide (ru-mmo). yan et al., [36] used three dimensional porous graphite plate electrodes for treating of petroleum refinery wastewater using an eo process. souza and ruotolo [37] used boron doped diamond anode (bdd), while santos et al., [38] used ti/ruo2 anode in their works. song and ning [39] used ruthenium mixed nomenclature adj. ms adjusted mean of the square ofat one-factor-at-a-time adj. r2 adjusted coefficient of multiple correlation pi prediction interval adj. ss adjusted sum of the square pred. r2 predicted multiple correlation coefficient ai the first-class(linear) major effect pt platinum aii second-class major effect re removal efficiency (%) aij the interaction effect rsm response surface methodology anova analysis of variance s standard error of the regression ao the intercept term se standard error of mean bbd box–behnken design seq. ss sum of square bdd boron doped diamond t time , min ci confidence interval t.d.s total dissolved solids cod chemical oxygen demand v volume of the effluent (l) cp reiterated number of the central point x1 current density ,m a/cm2 cr. % percentage contribution for each parameter x1 coded value of current density df the desirability function x2 ph dof degree of freedom x2 coded value of ph e voltage of cell, volt x3 nacl addition (g/l) ec energy consumption, kwh / kg cod x3 coded value of nacl addition eo electrochemical oxidation x4 time(min) f faraday constant , a s mol-1 x4 coded value of time i current applied , a xrd x-ray diffraction k number of process variables y represents the dependent variable (re) n number of runs ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 127 metal oxide electrode in the treatment of oil refinery effluents. lately, ghanim and hamza [40] investigated the treatment of petroleum refinery wastewater using pbo2 anode. all the above electrodes have many advantages and drawbacks depending on the type of oxidation and the composition of contaminants the present study reports an indirect anodic oxidation process for treating a petroleum refinery wastewater generated from al-diwaniyah petroleum refinery plant using a porous graphite with a high specific surface area as an anode material and application the design of experiments as an optimization method. the process parameters were optimized by using boxbehnken design (bbd). the quadratic model has been developed in terms of input factors such as current density, initial ph, nacl concentration, and time by performing the experiments based on the design matrix generated by rsm. this quadratic model was utilized for the assessment of parametric conditions that make cod removal maximum. no previous works have been conducted on the optimization of petroleum refinery wastewater using porous graphite anode. selecting the porous graphite as anodic material is based on its availability, high specific area, and low cost in addition to its activity as anode materials in the indirect anodic oxidation [36]. 2. 2. experimental work petroleum refinery effluent samples were provided by al-diwaniyah petroleum refinery plant. sample (40l) was collected from the feeding tank to the biological treatment unit and stored in closed containers at temperature 4 ºc until use. the characterization of this sample is shown in table 1. besides the properties of effluent taken from the settling tank of the final stage of the biological treatment unit that was measured by petroleum refinery plant administration with the permissible limit were mentioned in this table for comparison. the conductivity of raw water is 1.92 ms/cm which is low and resulted in increasing the cell potential, therefore supporting electrolyte should be used to increase the conductivity of the solution. sodium sulfate (na2so4) at a concentration of 0.05 m was used as a supporting electrolyte which gives final conductivity of 12.9 ms/cm which is within the required range to obtain low cell potential [37]. table 1. characteristics of the effluents in al-diwaniyah petroleum refinery plant. test feed tank sample settling tank* permissible limit* cod (mg/l) 590 65 100 ph 6.4 7.5 (6.9-9.5) t.d.s 960 1680 ……. cl(mg/l) 500 119 100 so4 -2 (mg/l) 13.67 400 400 turbidity(ntu) 28.49 6.44 41.3 conductivity(ms/cm) 1.92 ….. …… phenol(mg/l) 0.15 (0.01-0.05) 0.06 *provided by al-diwaniyah petroleum refinery plant administration. a circular jacketed perspex glass lab-scale batch electrochemical cell provided with perspex cover was used for the anodic oxidation treatment experiments. it has dimensions (100 mm inside diameter with a length of 200 mm and thickness of 5mm) and an active electrolyte volume of 1.0 l. the jacket was made from perspex and has external dimensions (130mm outside diameter with a length of 150 mm). the cover has external dimensions (130 mm outside diameter and thickness of 10 mm) and contains two slits for installing of electrodes and holes for inserting the probes of ph-meter and conductivity meter and sample taking out. a parallel plate configuration was adopted for the electrochemical reactor where stainless steel plate cathode (180 mm × 50 mm × 4 mm) and porous graphite anode (180 mm × 50 mm × 5 mm) were used. the distance between the cathode and the anode was fixed at 20 mm [40]. a digital direct current power supply (0–30 v, 0–5 a) type (uni-t, utp3315pf) was used to provide constant current during each experiment (galvanostatic mode). in each run, 1.0l solution was agitated using magnetic stirrer at a rotation speed of 500 rpm to achieve the proper mixing conditions then the required amount of the supporting electrolyte and nacl ( if needed) were added then mixing was continued at the same rotation speed during the experiment. all the experiments were carried out at constant temperature of 30 ±2 ºc using water bath (memmert, type: wnb22, germany). fig.1 shows the schematic diagram of the electrochemical oxidation experimental setup supported by the required information. the electrolyte ph was measured using a digital ph meter (hnna instrument inc.ph211, romania) and the electrolyte acidity was adjusted using hcl or naoh for appropriate experimental condition. figure 1. the schematic diagram of the experimental setup: 1) cell body, 2) jacket, 3) porous graphite anode, 4) cathode , 5) magnetic stirrer, 6) power supply, 7) voltmeter 8) ammeter , 9) ph-meter, 10) water bath circulator conductivity and tds were measured by using (hm digital inc. model com-100, korea). samples were taken and analysed to determine the cod and phenol concentration at the end of electrolysis. the concentration of total organic compounds in the effluent is expressed in terms of (cod). amount of cod in petroleum refinery effluents was measured by taken a sample (2ml) of effluent digested with k2cr2o7 as an oxidizing agent for 120 minutes at 150 °c in a cod thermos-reactor (rd125, lovibond). the digested sample was cooled down to room temperature then analyzed in spectrophotometer (md200, lovibond). phenol was measured by using method 8047 assigned by hach company/hach lange gmbh, usa. measuring of phenol concentration and cod were achieved three times and the average values were taken in this work. 2.1. anode porous graphite is used as anode. it is a rectangular piece of graphite electrode with porosity 20-26% used for arc furnace and supplied by tokai carbon co., ltd. its structure was identified by using x-ray diffractometer using philips analytical x-ray b.v. with pc-apd, 128 ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 diffraction software, philips expert, holland). the x-ray diffraction (xrd) is operated at 40 kv and 30 ma with cukα radiation as the x-ray source, λ=1.54056 å. the scan step time was 0.5 sec with a step size of 0.02 degrees and a scan range of 10 – 99.99 degrees. the topography of graphite surface is investigated by means of scanning electron microscopy (sem) using fesem tescan mira3, france. the measurement parameters were: av = 15 kv, bias = 0, spot = 3.0 and hv = 2 kv, bias = 1400 v. the total surface area of graphite was measured by bet method using device (bet tavana, iran) provided with software based on micrometrics: microactive for tristar ii plus 2.03. the cod removal efficiency was evaluated based on eq.1 [41] re% = [(codi –codf) /codi] × 100% (1) where re% stands for the cod removal efficiency, codi represents the initial cod (mg l−1), and codf is the final cod (mg l −1) the energy consumption (ec) in any anodic oxidation represents the amount of the consumed energy in the process for a kilogram of cod that requires digesting. ec in (kwh/kg) may be acquired with the use of eq. 2 [42]: ec = (𝐸 × 𝐼 × 𝑡 × 1000)/((𝐶𝑂𝐷𝑖 − 𝐶𝑂𝐷𝑓 ) × 𝑉) (2) where ec represents the energy consumption (kwh/kg cod), e represents the measured cell voltage (volt),i is the current (a), t represents the electrolysis time (h), codi and codf are the initial and final chemical oxygen demand (mg/l), and v represents the volume of the effluent(l). 2.2. design of experiments through application of mathematical and statistical collections, the relationship between a process response and its variables can be determined via adopting rsm [43]. in this study, the 3-level 4-factor box–behnken experimental design is employed to verify and check the factors that influenced on the removal of cod. current density (x1) initial ph (x2), nacl concentration (x3), and time (x4) were taken as process variables, while the cod removal efficiency was taken as a response. the scales of process variables were coded as -1 (low level), 0 (middle or central point) and 1 (high level) [44]. table 2 illustrates the process parameters with their chosen levels. box–behnken develops and improves the designs that needed for getting the suitable quadratic model with the required statistical properties though utilizing only a part of the required runs for a 3-level factorial. the number of runs (n) needed for carrying out of box–behnken design can be calculated by the following equation [45]: n =2k (k-1) + cp (3) where k is the number of process variables and cp is the reiterated number of the central point. in this research, twenty seven runs were conducted for evaluating the impacts of the process variables on the cod removal efficiency. table 3 illustrates the bbd proposed for the present research. table 2. process variables with their level for refinery wastewater treatment process parameters rang in box-behken design coded levels low(-1) middle(0) high(+1) xl-current density ( ma/cm2) 5 15 25 x2ph 3 6.5 10 x 3– nacl addition (g/l) 0 1 2 x4time(min) 20 40 60 table 3. boxbehnken experimental design run blocks coded value real value x1 x2 x3 x4 current density (ma /cm2) x1 ph x2 nacl (g/l) x3 time (min) x4 1 1 0 1 0 -1 15 10 1 20 2 1 0 -1 1 0 15 3 2 40 3 1 0 0 0 0 15 6.5 1 40 4 1 -1 0 0 -1 5 6.5 1 20 5 1 1 0 -1 0 25 6.5 0 40 6 1 0 -1 -1 0 15 3 0 40 7 1 1 1 0 0 25 10 1 40 8 1 1 0 0 1 25 6.5 1 60 9 1 0 0 1 -1 15 6.5 2 20 10 1 0 -1 0 1 15 3 1 60 11 1 1 0 1 0 25 6.5 2 40 12 1 0 0 -1 -1 15 6.5 0 20 13 1 0 0 -1 1 15 6.5 0 60 14 1 -1 1 0 0 5 10 1 40 15 1 -1 0 1 0 5 6.5 2 40 16 1 -1 0 -1 0 5 6.5 0 40 17 1 0 1 -1 0 15 10 0 40 18 1 0 -1 0 -1 15 3 1 20 19 1 0 0 0 0 15 6.5 1 40 20 1 1 0 0 -1 25 6.5 1 20 21 1 -1 -1 0 0 5 3 1 40 22 1 0 1 0 1 15 10 1 60 23 1 0 0 1 1 15 6.5 2 60 24 1 -1 0 0 1 5 6.5 1 60 25 1 0 1 1 0 15 10 2 40 26 1 1 -1 0 0 25 3 1 40 27 1 0 0 0 0 15 6.5 1 40 a second order polynomial model can be adopted based on bbd where fitting the interaction terms with the experimental data can be described by the following equation [46]: y= a0 + ∑ai xi + ∑ aii xi 2 + ∑ aij xi xj (4) where y represents the response efficiency (re), i and j are the index numbers for patterns, a0 is intercept term, x1, x2 … x_k are the process variables in coded form. ai is the first-order(linear) main effect, aii secondorder main effect and aij is the interaction effect. analysis of variance was performed then the regression coefficient (r2) was estimated to confirm the goodness of model fit. 3. results and discussion 3.1. characterization of anode figure 2 shows the xrd results of the porous graphite anode. it was coincided with the standard graphite structure having a reference code (96901-2231) (blue) [47]. the graphite structure analysis shows a sharp diffraction peak at 2θ = 26.6255ᵒ with c (002) having a d-spacing of 3.34802ǻ. the sem picture of porous graphite anode is shown in figure 3 with magnification power (7500). it was found that the porous graphite has high porosity structure where large pores are formed which is different than the normal rigid graphite that possess smooth non-porous structure. bet ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 129 surface area of the porous graphite was found to be 22.7509 ± 0.5307 m²/g which is higher than the bet of commercially available graphite felt (sgl carbon, gfa6 ea)(2.73 m2/g) [48]. figure 2. xrd pattern of graphite figure 3. sem image of porous graphite 3.2. statistical analysis for optimizing and studying the combined effects of the independent variables on the cod removal efficiency, twenty seven statistically designed batch runs were conducted for different combinations of process parameters. table 4 shows the experimental results including cod removal efficiency (re %) and energy consumption (ec). it can be seen that cod removal efficiency is in the range of 54.9898.80%. the energy consumption is in the range of (0.6-11.82) kwh/kg cod. minitab-17 software was used to analyse results of cod removal efficiency where an experimental relationship between cod removal efficiency and process parameters was obtained and formulated by the following quadratic model of cod removal efficiency (re) in term of uncoded (real) units of process parameters (eq.5): re% = 61.4 + 0.030 x1 2.99 x2 + 16.99 x3 + 0.176 x4 + 0.0322 (x1)2+ 0.054 (x2)2 1.16 (x3)2+ 0.00374 (x4)2+ 0.0016 x1*x20.070 x1*x30.00471 x1*x41.036 x2*x3 + 0.0121 x2*x4 + 0.0757 x3*x4 (5) table 4. experimental results of box–behnken design for cod r u n b lo c k s c u r r e n t d e n si ty ,( m a / c m 2 ) p h n a c l, ( g /l ) t im e , (m in ) r e % e , (v o lt ) e c , ( k w h /k g c o d ) a c tu a l p r e d ic t 1 1 15 10 1 20 59.00 57.69 5.4 2.78 2 1 15 3 2 40 98.80 95.82 4.9 3.02 3 1 15 6.5 1 40 76.55 76.55 5.2 4.12 4 1 5 6.5 1 20 63.20 62.61 3.8 0.60 5 1 25 6.5 0 40 74.59 76.18 7.3 9.40 6 1 15 3 0 40 73.90 75.99 5.5 4.28 7 1 25 10 1 40 76.30 78.07 6.67 8.62 8 1 25 6.5 1 60 98.50 99.93 7.06 11.8 9 1 15 6.5 2 20 68.39 75.63 5.04 2.23 10 1 15 3 1 60 98.80 99.74 5.5 5.14 11 1 25 6.5 2 40 98.60 96.01 6.81 7.08 12 1 15 6.5 0 20 54.98 55.79 5.34 2.84 13 1 15 6.5 0 60 79.23 78.15 5.87 6.46 14 1 5 10 1 40 61.20 63.10 3.49 1.11 15 1 5 6.5 2 40 86.10 81.04 3.44 0.80 16 1 5 6.5 0 40 59.30 61.21 3.9 1.27 17 1 15 10 0 40 61.60 56.29 6.08 6.54 18 1 15 3 1 20 80.00 77.38 5.36 2.03 19 1 15 6.5 1 40 76.18 76.55 5.28 4.21 20 1 25 6.5 1 20 81.10 77.57 6.56 4.09 21 1 5 3 1 40 81.56 82.80 3.5 0.89 22 1 15 10 1 60 81.20 80.04 5.21 5.64 23 1 15 6.5 2 60 98.70 97.98 5.46 5.06 24 1 5 6.5 1 60 84.37 84.96 3.67 1.29 25 1 15 10 2 40 72.00 76.12 5.07 4.34 26 1 25 3 1 40 96.43 97.77 7.1 7.60 27 1 15 6.5 1 40 76.93 76.55 5.27 4.10 where re% is the response, i.e. cod removal efficiency, and x1, x2, x3and x4 are current density, ph, nacl concentration, and time respectively, where the variables x1x2, x1x3 , x1x4, x2x3, x2x4, x3x4 represent the interaction effect of all the parameters of the model. (x1)2, (x2)2, (x3)2 and (x4)2 are the measures of the main effect of variables current density, ph, nacl concentration, and time respectively. eq. (5) shows how the cod removal efficiency is affected by the individual variables (linear and quadratic) or double interactions. values of positive coefficients revealed that the cod removal efficiency increased with the increasing of the related factors of these coefficients within the tested range while values of negative coefficients revealed the opposite effect. as can be seen current density, nacl concentration, and time were found to have a positive effect on the cod removal efficiency while ph has a negative effect. the results showed that effects of interactions are non-significant with a total contribution of (3.37%) from the model. the predicted values of the cod removal efficiency estimated from eq.5 are also inserted in table 4. the box-behnken design acceptability was recognized by using analysis of variance (anova). for examine hypotheses on the factors of the model, anova divides the total variation in a set of data into individual parts accompanied with specific sources of variation [49]. the acceptability of the model in anova analysis is determined based on fisher f-test and p-test. if the value of fisher is large then most of the variation in the response can be illustrated by the regression equation. p-value is used for evaluating whether f is large enough to position [°2theta] (copper (cu)) 20 30 40 50 60 70 80 90 counts 0 10000 40000 duaarb 130 ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 recognize if the model is statistical significance. (90)% of the variability of the model could be clarified when a p-value lower than (0.05) [50].table 5 illustrates anova for the response surface model. in this table, degree of freedom (df), sum of the square (seqss), percentage of contribution (cr. %) for each parameter, adjusted sum of the square (adj ss), adjusted mean of the square (adj ms), f-value, and p-value were evaluated. f-value of (34.03) and p-value of (0.0001) were obtained which elucidating high significance for the regression model. the multiple correlation coefficient of the model was 97.54% conforming the regression is statistically significant and only (2.46) % of the total variations is not confirmed by the model. the adjusted multiple correlation coefficient (adj. r2 = 94.68%) was in compatible with the predicted multiple correlation coefficient (pred. r2=85.87%) in this model. results of analysis of variance (anova) showed that the percent of contribution of current density is (14.01 %) which is lower than other parameters. this means that the system is not controlled by current, meanwhile ph and concentration of nacl have approximately the same significant effect on the process with contributions of 24.28%, 24.61% respectively. time has the larger effect with contribution of 31.27 %. it is clear that contribution of both ph and nacl concentration have the main effect on cod removal in the present work which means that the system is governed by reaction conditions in the bulk of solution not upon the electro oxidation of chloride ion on the surface of the electrode, i.e. the system is under bulk reaction control (reaction of chlorine with water) [51]. the linear term has the main contribution in the model with (94.17 %) followed by the square term with (1.91 %) as percent of contribution then 2-way interaction with a contribution of (1.46 %). table 5. analysis of variance for cod removal 3.3. effect of process variables on the cod removal efficiency the interactive effect of the selected variables and their effect on the response is assessed via a graphical representation of statistical optimization using rsm. figures (4-a,4b) show the effect of the initial ph on cod removal efficiency for various values of current density (5-25 ma/cm2) at constant nacl conc. (1g/l) and time (40min.). figure (4-a) represents the response surface plot while figure (4-b) shows the corresponding contour plot. from surface plot, it is clear that, at current density (5 ma/cm2), a sharply decreasing in cod removal efficiency occurs as the initial ph increased from 3 to 10. this effect of ph on removal efficiency is in agreement with previous works [40, 51]. this behaviour can be explained as at high ph the active chlorine is present as hypochlorite that is less strong oxidant towards organic species with respect to hypochlorous acid which is highly strong oxidant and it is the main species present at ph close to 2 [51]. at ph of 3, the results showed that cod removal efficiency is increased approximately exponentially with increasing of current density from 5 to 15 ma/cm2. similar observation was found when ph is 10. this behaviour of current density effect on cod removal is in agreement with previous work [37,38] and could be explained by an increase in current density would be led to higher generation of hypochlorous acid in acidic solution and hypochlorite in alkaline solution which favouring organic compounds degradation by the indirect oxidation process [38]. the corresponding contour plot confirms that value of the cod removal efficiency ≥90% lies in a small area in which the current density ranged between 18.5-25 ma/cm2 and ph in the range (3-5). the effect of nacl concentration (addition of nacl) on the cod removal efficiency for different current density (5-25 ma/cm2) at constant ph(6.5) and time (40min.) is shown in figures (5-a,5-b). the response surface plot fig. (5-a) shows that cod removal efficiency is linearly increased with increasing of nacl concentration at current density 5ma/cm2. similar trend occurs at current density of 25 ma/cm2. these results are in agreement with the results observed in the literature [40].the corresponding contour plot fig.(5-b) confirms that value of the cod removal efficiency ≥90% lies in a small area in which the current density ranged between 20-25 ma/cm2 and addition of nacl at concentration between (1.5-2.0 g/l). figures (6-a,6-b) show the effect of time on the cod removal efficiency for various values of current density (5-25 ma/cm2) at constant ph(6.5) and nacl conc. (1g/l). figure (6-a) shows that the cod removal efficiency is quickly increased with increasing of time at low value of current density. the same behaviour was observed as the current density reach to 25 ma/cm2. these results are in agreement with the results observed in the literature [37, 38, 40]. the corresponding contour plot fig. (6-b) confirms that value of the cod removal efficiency ≥90% lies in a small area in which the current density ranged between 17.5-25 ma/cm2and times in range of 45-60min. therefore, application of rsm will lead to identify the feasible optimum values of the studied factors in addition to its role in giving valuable information on interactions between the factors. figure 7 shows the interaction plot among process paramours for cod removal efficiency (re %). it can be seen that no significant interactions among variables were observed. source dof seq. ss cr.(%) adj. ss adj. ms f-value p-value model 14 4676.67 97.54 4676.67 334.05 34.03 0.001 linear 4 4515.05 94.17 4515.05 1128.76 115.0 0.001 (x1) 1 671.85 14.01 671.85 671.85 68.45 0.001 (x2) 1 1164.07 24.28 1164.07 1164.07 118.6 0.001 (x3) 1 1179.89 24.61 1179.89 1179.89 120.2 0.001 (x4) 1 1499.24 31.27 1499.24 1499.24 152.8 0.001 square 4 91.47 1.91 91.47 22.87 2.33 0.115 x1*x1 1 60.81 1.27 55.27 55.27 5.63 0.035 x2*x2 1 2.14 0.04 2.33 2.33 0.24 0.635 x3*x3 1 16.58 0.35 7.22 7.22 0.74 0.408 x4*x4 1 11.95 0.25 11.95 11.95 1.22 0.292 2-way inter. 6 70.15 1.46 70.15 11.69 1.19 0.374 x1*x2 1 0.01 0.001 0.01 0.01 0.00 0.971 x1*x3 1 1.95 0.04 1.95 1.95 0.20 0.664 x1*x4 1 3.55 0.07 3.55 3.55 0.36 0.559 x2*x3 1 52.56 1.10 52.56 52.56 5.36 0.039 x2*x4 1 2.89 0.06 2.89 2.89 0.29 0.597 x3*x4 1 9.18 0.19 9.18 9.18 0.94 0.353 error 12 117.78 2.46 117.78 9.82 lack-of-fit 10 117.50 2.45 117.50 11.75 83.55 0.012 pure error 2 0.28 0.01 0.28 0.14 total 26 4794.45 100 model summary s r2 r2(adj.) press r2(pred.) 3.1329 97.54% 94.68% 677.436 85.87% ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 131 (a) (b) figure 4. response surface plot (a) and contour plot (b) for the impact of ph and current density on the cod (re%)( hold values nacl=1g/l, time =40 min) (a) (b) figure 5. response surface plot (a) and contour plot (b) showing the effect of nacl concentration and current density on the cod removal efficiency (hold values: ph=6.5, time=40min). 3.1. the optimization and confirmation test to minimize energy losses and consequently treatment cost losses for any electrochemical removal system, optimization of its process conditions is essential and should be achieved. for optimizing the system, many criteria were identified to achieve the desired objective via maximizing the desirability function (df) through adjusting the weight or importance, which could alter the characteristics of an objective. the target fields for the variables have five options: none, maximize, minimize, objective and within the range. the goal of electrochemical removal of cod is designated as the ‘maximum’ with corresponding ‘weight’1.0. the independent factors studied in this work were established within the range of the designed levels (current: 5-25 ma/cm2, ph: 3-10, nacl: 0-2g/l and time: 20-60 min.). the lower limit value of the cod removal efficiency was assigned at 54.98%, while the upper limit value was assigned at 98.8%. the optimization procedure was achieved under these boundaries and settings and the results are shown in table 6 with the desirability function of (1). for their validation, two confirmative experiments were performed using the optimized parameters, the results are displayed in table 7. after 60 min of the electrolysis, cod removal efficiency of 98.16% as an average value was achieved in ph=3 which is in compactable with the range of the optimum value getting from optimization analysis with desirability function of (1) (table 6). therefore, adopting box–behnken design in combined with desirability function is successful and efficient in optimizing cod removal using porous graphite anode. additional experiment was conducted under the same optimum conditions with one exception that using initial ph of 7 instead of 3. the results show that cod removal efficiency in this case was 92.5% leading to a final cod level of nacl(g/l) 1 time(min) 40 hold values 4 6 8 70 08 4 6 01 2 18 21 224 09 1 00 %er )2mc/am(ytisned tnerruc hp urface plots of re% vs cu rent density(ma/cm2); phr ph c u rr e n t d e n s it y (m a / c m 2 ) 109876543 25 20 15 10 5 > – – – – – – < 65 65 70 70 75 75 80 80 85 85 90 90 95 95 re% contour plot of re% vs current density(ma/cm2); ph ph 6.5 time(min) 40 hold values 0 1 60 70 80 0 6 2 2 81 21 242 90 e%r rent denruc t )2mc/am(yis l(g/l)an c urface plot of re% vs curres t density(ma/cm2); nacl(g/l)n nacl(g/l) c u rr e n t d e n si ty (m a /c m 2 ) 2.01.51.00.50.0 25 20 15 10 5 > – – – – – – < 65 65 70 70 75 75 80 80 85 85 90 90 95 95 re% contour plot of re% vs current density(ma/cm2); nacl(g/l) 132 ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 43ppm which is below the allowable limit determined by al-diwaniyah petroleum refinery plant administration (table1). table 8 shows a comparison between the properties of wastewater effluent and the treated effluent based on the present work. it can be seen that treated effluent has better properties and its properties are in agreement with the standard limits for discharging effluent (table 1). cod removal efficiency of 98.8%, phenol removal efficiency of 99.6%, and turbidity removal efficiency of 95.65% base on the raw effluent properties were achieved in the present work confirming the activity of porous graphite anode in the indirect oxidation treatment of wastewater generated from al-diwaniyah petroleum refinery plant. table 6. optimum of process parameters for maximum cod removal efficiency (re %). importance weight upper target lower goal response 1 1 98.8 maximum 54.98 maximum re (%) results solution: parameters 95% pi 95% ci se fit df r e (%) fit time (min) nacl (g/l) ph current density (ma/cm2) (99.32; 124.25) (101.36; 122.21) 4.79 1 111.785 60 2 3 25 (a) (b) figure 6. response surface plot (a) and contour plot (b) showing the effect of time and current density on the cod removal efficiency (hold values: nacl=1g/l, ph=6.5). figure 7. interaction plot for cod removal efficiency (re %). ph 6.5 nacl(g/l) 1 hold values 20 04 60 80 20 6 60 2 81 12 224 100 e%r rent denruc c )2m/am(ytis et (min)im urface plot of re% vs current densits (ma/cm2); time(min)y time(min) c u rr e n t d e n si ty (m a /c m 2 ) 6050403020 25 20 15 10 5 > – – – – – – < 65 65 70 70 75 75 80 80 85 85 90 90 95 95 re% contour plot of re% vs current density(ma/cm2); time(min) ahmad s.fahim and ali h. abbar//al-qadisiyah journal for engineering sciences 13 (2020) 125–135 133 table 7. confirmative value of the optimum cod removal efficiency r u n c u r r e n t d e n si ty ,( m a /c m 2 ) p h n a c l. ( g /l ) t im e , (m in ) e , (v o lt ) c o d , (p p m ) r e % e c . k w h /k g c o d in o u t a c tu a l a v e r a g e 1 25 3 2 60 6.4 572 14 97.55 98.16 9.85 2 25 3 2 60 6.2 569 7 98.77 3 25 7 2 60 6.0 585 43 92.65 9.68 table 8. comparison between the wastewater effluent and the treated effluent. parameter effluent cod (ppm) phenol (ppm) turbidity (ntu) so4 -2 (ppm) cl (g/l) raw effluent 590 0.15 28.49 13.67 0.5 treated effluent 7 (98.8%) 0.0006 (99.6%) 1.24 (95.65%) 0.459 0.773 3.2. comparison with previous works the optimum conditions revealed that the indirect anodic oxidation of al-diwaniyah petroleum refinery could be performed using porous graphite anode with an initial cod (572 ppm) of wastewater where cod removal efficiency of 98.16% could be achieved at the end of an electrolysis time of 60 min. in this case an energy consumption of 9.85kwh/kg cod is required. in table 9, we have given an extensive comparison between the present work with other related work for petroleum refinery wastewater degradation by indirect anodic oxidation process using different types of electrode under various conditions. table 9. comparison of petroleum refinery wastewater degradation study using different type of electrode with literature under various conditions electrode type cod ph current density (ma/cm2) time (min) cod re (%) ec (kwh/ kg cod) ref. porous graphite 1021 6.5 12v 60 92.8 -----36 bdd 666 9.5 50 360 95 37 ti/ruo2 712 7.3 10 120 96 38.7 38 ruthenium mixed metal oxide 593 9 25 180 85 -----39 pbo2 500 4 50 120 84.8 ---40 porous graphite 572 3 25 60 98.16 9.85 this work it can be seen that the results of the present work are better than pbo2 results. this is probably due to the high surface area of porous graphite that leads to liberation of more chlorine gas. hence more reaction with h2o leading to generation more hclo in acidic solution that degrades the organic compounds in wastewater. comparison with work of yan et al. [36] which used porous graphite anode is not conclusive since they operated at constant voltage not at constant current density as the case of present work. however their results are good in comparison with other works confirming the activity of porous graphite in oxidation of petroleum refinery wastewaters. energy consumption in the present work is lower than that obtained by santos et al. [38] work in spite of higher current density used in the present work. 4. conclusions the present research focused on investigating the effect of many operating parameters such as current density, initial ph, nacl concentration, and time on the cod removal in the treatment of aldiwaniyah petroleum refinery wastewater using indirect anodic oxidation process on porous graphite anode and adopting box-behnken design as an optimization method. the experimental data were fitted to a second-order polynomial equation which was utilized for optimization of operating parameters. the optimum conditions were current density of 25 a/cm2, nacl concentration of 2g/l, ph equal to 3, and electrolysis time of 60 min, where cod removal efficiency of 98.16%, with energy consumption of 9.85 kwh/kg cod were obtained. results show that both ph and nacl concentration have the main effect on cod removal in the present work which means that the system is governed by reaction conditions in the bulk of solution not on the electrooxidation reaction on the surface of electrode. this was in agreement with most mechanisms of the indirect anodic oxidation reaction reported in the literature. acknowledgment the authors wish to acknowledge the helpful and technical assistance given by the staff of chemical engineering department, college of engineeringuniversity of al-qadisiyah. references [1] i. p. i. e. c. association, petroleum refining water/wastewater use and management: ipieca operations best practice series, (2010). 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[51] o. scialdone, s. randazzo, a. galia, and g. silvestri, electrochemical oxidation of organics in water: role of operative parameters in the absence and in the presence of nacl, water research, 43(8) (2009) 2260–2272. template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 396 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. kinetics of hydrogen separation from refinery off-gas abbas khalaf mohammad, college of engineering, university of al-qadisiyah,al-qadisiyah, iraq e mail: abbas.shuaab@qu.edu.iq; dr_abbas_k@yahoo.com nawras shareef sabeeh, college of engineering, university of al-qadisiyah,al-qadisiyah, iraq e mail: nawras.sabeeh@qu.edu.iq abstract: adsorption and desorption kinetic curves for equimolar hydrogen – methane mixture on molecular sieve type 5a were experimentally obtained for pressure range 0.122 – 3.546 mpa.the linear driving force rate expression model was used to simulate the dynamic of adsorption and desorption in adiabatic fixed bed adsorber. the model takes into account the interference effects for non-linear isotherms and non-isothermal system. the equations were solved by backward finite difference method with a fixed gridding technique. the individual mass transfer parameters were obtained by matching the theoretical with the experimental data and found to be equal to 8.510 s-1 and 0.783 s-1 for hydrogen and methane, respectively.the predicted effluent histories were shown to be in close agreement with the experimental data for the system. the lowest relative capacity of the bed for methane was almost approximately 95% of that predicted equilibrium capacity. the predicted temperature profiles tracked the experimental temperature data points, but with higher values. furthermore, the maximum temperature increasing was observed for the adsorption of methane onto 5a molecular sieve at 35 atmospheres and was recorded as 44 k. keywords: hydrogen, methane, sorption, kinetics, 5a molecular sieve. nomenclature symbol notation unit a1, a2, a3, a4 di, do langmuir isotherm coefficients inner, outer diameter of adsorption column m hw wall heat transfer coefficient w m-2 k-1 kgi mass transfer parameter for component i s-1 qi, qj adsorbed phase concentration of component i, j mole g-1 qm monolayer adsorbed phase concentration mole g-1 q* adsorbed phase concentration at equilibrium mole g-1 t time s u superficial gas velocity m s-1 yi, yj mole fraction in gas phase for component i, j mailto:dr_abbas_k@yahoo.com mailto:nawras.sabeeh@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 397 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. z axial coordinate m bi, bj adsorption coefficient in langmuir equation for component i, j pa-1 cpg, cpp, cpw thermal capacity of gas phase, particles and wall, respectively j mole-1 k-1 f relative error coefficient l packed bed length m n number of experimental data points p absolute pressure pa tg, tw absolute temperature of gas phase and wall, respectively k εt total void fraction of the packed bed ρb, ρg, ρw density of packed bed, gas phase and wall, respectively kg m-3 ∆hj heat of adsorption for component j j mole-1 introduction in the not too distant past, any hydrogen byproduct of an operation plant was vented, flared or grudgingly used as a fuel. recently, a combination of factors has substantially increased its utility as a raw material. petroleum refiners are forced to use sour crude, which must be hydro-treated; chemical manufacturers are asked to supply more and more ammonia for fertilizer. these and other applications have increased total domestic hydrogen consumption [1]. five types of processes were found in literature for separation of hydrogen from gas mixtures. these processes include: condensation, absorption, diffusion, adsorption and electrochemical separation [1, 2]. the last fifty years have testified an enormous growth of gas adsorption processes that has made adsorption system a major tool for purification and for separation in chemical, biochemical and petroleum industry. the propagation is an outcome of a spectrum of scientific and engineering developments. this was launched by the discovery of synthetic molecular sieve zeolite and the adsorption cycles. these inventions followed by a progression of technical and theoretical improvements. the main advantages of adsorption as a separation technique, compared with the other processes are that in considerable situations higher selectivity can be gained by adsorption than by any of the another techniques, and adsorbents have a comparatively high capacity for volatile substances, even at little partial pressures. the characteristic of high selectivity covenants more efficient separation while high capacity permits the usage of higher temperature and lower pressure [3]. gas adsorption operations comprise the eclectic adsorption of one or more ingredients of a gas at the surface of micro-porous solid. physical adsorption is usually pronounced in separation processes. therefore, by increasing the temperature of the adsorbent or reducing the adsorbate partial pressure, the adsorbate can be desorbed. desorption permits retrieval of adsorbates in those separation processes where they are worthy and it allows reusing of the adsorbent for more cycles [4]. the adsorption technique is well-suited to provide high purity hydrogen because of the great selectivity difference between hydrogen and other components such as co2, ch4 and co on solid adsorbents. particularly activated carbon and molecular sieves were usually used [5]. it was found in our earlier work that 5a molecular sieve has better adsorption characteristics than activated carbon in the capacity, heat of adsorption, affinity and selectivity [6]. dynamic data are needed to avoid excessive laboratory and pilot plant facilities. to obtain such data, adsorption models are used to predict it. large numbers of researchers have studied the issue, and the solution that has been acquired can be in general categorized into two kinds: the equilibrium and the non– equilibrium theories [7]. equilibrium case may attained if a pure non-porous adsorbent surface was bared to a gas and the boundary layer neighboring to the surface gave no resistance to transfer of gas to the surface. physical adsorption at a surface is virtually instantaneous so that the rate of adsorption in a micro-porous adsorbent is almost invariably controlled by diffusional resistance to mass transfer rather than by the intrinsic surface kinetics [8]. there is a formidable body of literature dealing with the solution of fixed bed equations for non-equilibrium operation. two general approaches can be discerned. the first is deductive approach; the relevant mechanisms of transfer are picked out and combined to give a rate equation. the second is inductive in the sense that a solution is used which has been found for a particular kind of rate expression. al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 398 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. the actual conditions of operation for which the solution is required are then arranged in the form of this rate expression [9]. analytical solutions of the adsorption process exist in a few special cases only. graphical solutions have occasionally been utilized to evaluate the result of a single and multi–component adsorption process. however, when an exact prediction is necessary, the numerical methods remain to be the means only. this is predominately valid for a multi–component process with diversified mass and heat transform conditions [10]. essentially, three kinds of numerical methods have been utilized to solve numerical simulations of the non–equilibrium multi–component adsorption processes: the characteristics method, the orthogonal collocation method and finite difference method [11]. the finite difference method is extremely used due to its efficiency, simplicity in solving parabolic and hyperbolic equations and simple of modifying initial and boundary conditions [4]. the finite difference methods can be classified to implicit and explicit methods. although explicit methods are non-iteration, they are less accurate and usually require more time for computations due to the limiting stability. the implicit method yields elevated accuracy and it is stable for any case [11]. the objective of the present study is to derive a general mathematical model of gas separation by adsorption process and to show how this model can successfully be used to analyze typical hydrogen recovery processes. the system of partial differential balance equations along with the equilibrium and rate relationships with the relevant initial and boundary conditions were solved for adsorption and desorption steps. the calculations reveal that the model provide a rather valid description, both quantitative and qualitative, of the complex hydrogen separation processes differing in the values of operating variables. the model can thus be used in designing new and optimizing the already operating adsorption installations. also, it can be of tremendous help in illustrating the relative importance of the various parameters involved in adsorption processes. 1. experimental work the apparatus was designed for experimentally simulating the adsorption and desorption processes, and qualified for extensive range of operating conditions (adiabatic, high temperature, pressure and flow rate, etc.) for bulk gas separation. the equipment was controlled and automated, with the only manual steps being the samples analysis and the flow rates and pressure recording. a schematic diagram and photographic picture of the equipment are shown in figures 1 and 2, respectively. the sorption column was a stainless steel pipe 33 mm internal diameter and 670 mm long. fine mesh gauze plate and a stratum of glass wool are putted at the two ends of the column to catch adsorbent in position and prohibit heat loss from bed ends. all lines were ⅛ inch (3.2 mm o.d. and 2.4 mm i.d.) stainless steel. three solenoid valves (j. burnham comp. ltd. type 18/30-k) placed at the upper, lower and feed points were utilized to change the direction of flow in and out of the column. these valves were controlled by electrician timers. they were set to work at desired period of times. a check valve was putted in the purge line to prevent any back flow. the purge line was regulated by two regulators connected in series. a pressure gauge (gallenkamp aric) was placed at the head of the column to read the pressure history of the process. an insulation layer of glass wool wrapping the column makes the variation of temperature in the radial orientation as little as possible. the insulation layer also simulates adiabatic condition which approximates industrial adsorption processes when wide diameter columns are utilized. the axial distribution of temperatures were recorded and measured via multiple channels digital recorder (dacq tr-2721) at top, middle and bottom locations of the bed. this was accomplished by three downy thermocouples (1/16 inch) covered by a small (1/8 inch) safeguard pipe of copper which was inserted to the midst of the adsorption column. al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 399 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1. schematic diagram of apparatus used for sorption kinetics measurements figure 2. photographic picture of apparatus used for sorption kinetics measurements al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 400 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. the intake gases pipes were coiled (approximately 200 cm long) and immersed in a water bath to preheat the gas streams. the output flow rates were regulated by two needle valves (micro-hooke mite) and monitored by two rotameters (gec-elliott, ltd.). prior to each experiment, the commercial grade 5a molecular sieve (rhone poulenc industries ltd.) was regenerated by a vacuum oven (gallenkamp) which was operated at 10 kpa pressure and 373 k temperature for overnight, in order to remove previously adsorbed gases from the adsorbent surface. a weighted specimen of the adsorbent material was packed into the sorption column. a stream of hydrogen was continuously passed through the apparatus for about 120 min or until the whole adsorbent bed reaches the temperature of the water bath (303 k). through this period of time, the gas chromatography unit was switched on and allowed to warm up. operation initiated by modifying the intake gas from pure hydrogen to feed gas mixture (49.25% h2 – 50.75% ch4). at the same time, the outflowing gas concentration and flow-rate were measured. at the latest, the period of time required for the shock–front to navigate the adsorbent column was gained. the gas pressure was adjusted by setting the pressure regulator and the outlet flow rate was adjusted by using a needle valve. at the same time, thermocouples outputs were monitored continuously at three different locations from entrance of the bed to define the temperature breakthrough curves at these positions. on completion the adsorption run, the mixture supply was cut off. hydrogen was then supplied to the bed until the adsorbate was completely removed from the adsorbent. same pressures and flow rates were used for carrying the adsorption and desorption runs. the effluent from the process was sampled by passing through a 0.5 cm3 sample nub by means of a sampling valve connected to the exhauster. the samples always introduced at atmospheric pressure by a sub-side stream of the effluent gas. the samples were analyzed by using gas-solid chromatographic unit (varian vesta, 6000) in accordance with a modified standard test [astm d1946-90 (2015)]. 2. mathematical work predictive model for multi-component gas adsorption is requested in the designing of adsorber and adsorption processes. the magnitude of calculations participated is linked to the grade of complication of these models. therefore, many reasonable assumptions were introduced to decrease the time and number of computations, also increase the accuracy of solution by decreasing the round-off and truncation errors. the main assumptions based in the emergence of the model are: 1. the operation is adiabatic since the experimental adsorption column is covered with a thick layer of insulator and also to simulate the large diameter adsorbers in industrial applications. 2. the immediate thermal equipoise dominates between the solid and gas materials [12]. 3. the longitudinal dispersion in the bed is insignificant for mass and heat. this assumption is based on large peclet number (pe) accompanying the process [13]. 4. the pressure drop across the adsorbent bed is negligible. 5. the velocity profile is flat due to high reynolds number (re) and production rate [14]. 6. the radial gradient in the bed is negligible for mass and heat [15]. the dynamic behavior of the process when subjected to the above assumptions was described by the following set of equations and appropriate initial and boundary conditions. by taking a differential control volume element of the adsorption column, we get: material balance equation for sorbate i (assume ideal gases) in the control volume is: 0 2 1                      j j i i g bii t t q y t q z y u t y    i=1,2 (1) energy balance equation in the fluid and solid phases is: al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 401 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved.     0 4 2 1                j j jb wg i wg ggggg g pbggt t q h tt d h z t ucp z u tcp t t cpcp   (2) energy balance equation for the packed bed wall is:   041 2                    wg i ww ww i o tt d h t t cp d d  (3) the equilibrium adsorption isotherm relationships for ith component in a gas mixture could be expressed by extended langmuir isotherm equation as follow [6]:     2 1 1 j jj iimi i pyb pybq q i=1,2 (4) the b and qm coefficients count on temperature as follow: 2 1 a gm taq  (5) gtaeab 4 3  (6) the mass transport rate between the solid and gas in the linear driving force (ldf) model is given by a relationship of the form [7]:   i * igi i qqk t q    i=1,2 (7) it was presumed that the gas composition and pressure in the bed at zero time were known. the walls and gas temperatures are equivalent to the room temperature (pretreatment of the apparatus). at the beginning of desorption step, the concentration profile in the adsorbed and gas phases and the temperature distribution through the column stay the same as those at the termination of the adsorption stage (frozen profiles). the system of the marching non-linear parabolic partial differential equations, entire with rate and equilibrium relations and the suitable initial and boundary conditions was solved by the implicit backward finite difference procedure with stationary gridding method. the solution was progressed for the adsorption and desorption processes by using gauss-seidel iterative method. the problem variables were described at nub points of network of co–ordinate strips in terms of point samples. taylor series expansions were utilized to create finite differences approximation of variables derivatives by means of point samples of unknowns at every mish points and its adjacent neighbors. the variables derivatives were exchanged by the finite differences approximation fructifying algebraic equations for the unknowns at every mish point. absolute tolerance procedure was used as a convergence tolerance method because it is independent on the scaling of the variable and it is useful if the variable is convergence to any value [16]. this is very important especially for mole fraction determinations before the occurring of shock waves. the computation was initiated by assuming a set of guessed values for velocity, mole fractions and gas temperature for the segment. the calculations were terminated when the difference of calculated values between two successive iterations is within the tolerance 10-3 for the velocity and the temperature and within 10-4 for mole fractions. al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 402 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. the solution to the system discussed includes the gas and solid concentration profiles and the gas and wall temperature profiles along the column for a number of temporal points. we have used matlab version 6 (mathwork inc., massachusetts) numerical analysis package interactively to solve the equations and plot response curves in this study. the computation time using pentium iii pc was approximately equal to ten minutes for adsorption or desorption process under specified conditions. 3. results and discussion a series of sorption (adsorption-desorption) kinetic curves were obtained experimentally for the system called (hydrogen – methane) on 5a molecular sieve. these kinetic curves were matched with predicted kinetic curves in order to characterize and test the model, as well as, to estimate the values of the kinetic parameters which describe the dynamic behavior of adiabatic fixed bed adsorber. experimental and theoretical profiles are presented in figures as follow: the y-axis represents the dimensionless concentration (y/yfeed) or the dimensionless gas temperature (tg/tgfeed) while the x-axis represents either the dimensionless time (tu/l) or the dimensionless stoichiometric time (t/tstoichiometric). we generated a various adsorption – desorption curves with varying kgi(s) from the numerical solution of the equations of the model. the magnitudes of the parameters correspondent to the conditions of the experiments must be got by matching the theoretical and experimental results. earlier work [17] shows that the simultaneous matching of sorption results gives an unambiguous calculation of these parameters. the model mass transfer parameters were calculated by minimization of the objective function:       2 1    n i ii calexp yyf (8) for all the adsorption and desorption experiments, the mass transport parameters for each single component (hydrogen and methane) were calculated separately for each experiment and then rated for all the experiments. moreover, a procedure based on trial and error was used for parameters determination. the comparison between the theoretically predicted curves and experimentally measured points are shown in figures 3 – 10 and the relevant mass transfer parameters were found to be equal to 8.510s-1 and 0.783s-1 for hydrogen and methane, respectively. it is clearly seen that the fit is good enough to conclude that the model results generates an acceptably valid impersonation of adsorption and desorption results. it is also recognized that the fit for adsorption curves are worse than for desorption curves because the rate of desorption was much slower than the rate of adsorption. hence, more experimental time was required for complete bed cleaning and more experimental data points (30 second time interval was chosen). therefore, more desorption experimental data points were matched the theoretical curves. figures 3 – 6 show that the lowest relative capacity of the bed for methane approximately 95 % of that predicted equilibrium capacity. this is because some adsorption active sites of the adsorbent were occupied by hydrogen molecules and to a lesser extent because of rate and thermal effects of adsorption, which may cause early breakthrough. the total pressure increasing has no effect on the relative gas and solid composition for the system h2-ch4-5a molecular sieve as shown in our previous work [6]. therefore, the first reason is the predominant reason because the relative capacity of the bed is almost constant at 95 %, while the experiments were conducted at different pressures and flow rates. the effect of adsorption and desorption pressures on response curves are illustrated in figures 3 – 10. it may be seen that the response curves are more diffuse at the higher pressures, as is to be expected on account for the somewhat greater deviation from the rectangular limit. this deviation may be attributed to several reasons. the density of the gas increases with pressure increasing, hence much more mass transfer resistance occurs through bulk gas phase and more diffuse response curves result. the amount of methane adsorbed to achieve equilibrium decreases with pressure decreasing, therefore less gas molecules transfer through the porous adsorbent pellets required to achieve equilibrium. finally, the much more gas molecules adsorbed at high pressures elaborate more heat of adsorption, then some adsorbed molecules around the shock wave desorb. al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 403 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3. kinetic of adsorption for the system hydrogenmethane-5a molecular sieve at 1.2 atm figure 4. kinetic of adsorption for the system hydrogenmethane-5a molecular sieve at 5 atm al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 404 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5. kinetic of adsorption for the system hydrogenmethane-5a molecular sieve at 20 atm figure 6. kinetic of adsorption for the system hydrogenmethane-5a molecular sieve at 35 atm al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 405 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7. kinetic of desorption for the system hydrogenmethane-5a molecular sieve at 1.2 atm figure 8. kinetic of desorption for the system hydrogenmethane-5a molecular sieve at 5 atm al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 406 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 9. kinetic of desorption for the system hydrogenmethane-5a molecular sieve at 20 atm figure 10. kinetic of desorption for the system hydrogenmethane-5a molecular sieve at 35 atm al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 407 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. some deviation from the well-known symmetrical (s) shape breakthrough may be noted from figures 3 – 6 and this deviation increases with pressure increasing. this is because that the second half of the breakthrough curves are more diffuse than the first half of it. this suggests a mechanism other than mass transport might control the rear part of the breakthrough curves is considered as a temperature control part. this result is in agreement with earlier work [18]. the effect of product flow rate on the response curves is clearly noticed from observing figures 3 – 6. it was noticed that a slower gradients were obtained with a slower flow rates, because mass transfer resistances increase with flow rate decreasing. in figures 11 and 12 the kinetic and thermal curves at three axial positions in the column are shown. from the first figure, it was recognized that the concentration wave fronts become more and more diffuse as the bed length increases. this is may be attributed to the diffusion resistances which prevent rapid uptake and cause an early and more diffuse breakthrough curve of methane. the temperature curves demonstrate the importance of heat of adsorption in the adsorptive separation processes. there are significant rises of system temperature due to relatively high concentrations of adsorbates used, as shown in figure 12. the maximum temperature increasing was observed for the adsorption of methane onto 5a molecular sieve at 35 atmospheres and was recorded as 44 k. hence, the heat balance equations are necessary for the prediction of response curves, otherwise, large deviation may be obtained. furthermore, thermal effects were expected to be larger for the adsorption of higher hydrocarbons, since these compounds have higher heat of adsorption. figure 11. concentration distribution for the system hydrogenmethane-5a molecular sieve at 35 atm and 5 l/min at stp al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 408 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 12. temperature distribution for the system hydrogenmethane-5a molecular sieve at 35 atm and 5 l/min at stp the predicted temperature profiles tracked the experimental temperature data points, but with higher values. these variations could be elucidated as follows. the model was neglected the effects of axial heat conduction through the column wall and radial heat conduction. these parameters might be important in the experimental equipment used in this study. furthermore, the heat liberated from adsorption is function of coverage of adsorption surface. this final effect was also neglected in the model equations by assuming constant heat liberation through the whole range of operation. the temperature profiles rises approximately simultaneously with the concentration breakthrough curves because the elaborations of heat and methane adsorption are simultaneous phenomena. therefore, the system temperature at lower axial position rise sharply as concentration do, this is because the heat liberated by methane adsorption. the cooling zone moves very slowly and with comparatively tiny inclination through the column. the inclination of the cooling wave front becomes steeper with a detraction height of the column. this is because that the convective stream holds the excess heat from the forward part of the bed to the rear cold part, then more diffuse response curves produced. conclusions 1. the model obtained in this study gives an adequate characterization of the breakthrough of the hydrogen-methane mixture on 5a molecular sieve. 2. increasing in pressure or decreasing in flow rate give more diffuse breakthrough curves for the system of hydrogen-methane on 5a molecular sieve. 3. the total pressure increasing has no effect on the relative gas and solid composition for the system h2-ch4-5a molecular sieve and the lowest relative capacity of the bed for methane approximately 95% of that predicted equilibrium capacity. 4. heat balance equations are necessary for the prediction of response curves due to relatively high concentrations of adsorbates used, which cause a significant rise of system temperature. al-qadisiyah journal for engineering sciences vol. 11, no. 3 issn: 1998-4456 page 409 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. biodata abbas khalaf mohammad is associate professor at college of engineering, university of al-qadisiyah, al-qadisiyah, iraq. nawras shareef sabeeh is lecturer at college of engineering, university of al-qadisiyah, al-qadisiyah, iraq. references 1. rabiei, z. hydrogen management in refineries, „petroleum and coal", 54 (4), 357 (2012). 2. oztek, m.t. recovery of hydrogen and helium from their mixtures using metal hydrides, m.sc. thesis, university of central florida (2005). 3. mohammed, r.r. separation of multi-components gas mixtures by adsorption, ph.d. thesis, university of technology (1996). 4. huang, c.c.; fair, j.r. study of the adsorption and desorption of multiple adsorbates in a fixed bed, „aiche j.", 34, 1861 (1988). 5. cassidy, r.t.; holmes, e.s. twenty-five years of progress in adiabatic adsorption processes, „aiche symp. ser.", 80, 68 (1984). 6. mohammad, a.k.; sabeeh, n.s. comparative study for adsorption of hydrogen-methane mixture on activated carbon and 5a molecular sieve, „braz. j. chem. eng.", 35 (2), 795 (2018). 7. shafeeyan, m.s.; daud, w.m.a.w.; shamiri, a. a review of mathematical modeling of fixed-bed columns for carbon dioxide adsorption, „chem. eng. res. des.", 92, 961 (2014). 8. carberry, j.j. chemical and catalytic reaction engineering, dover publications inc., mineola, new york (2001). 9. richardson, j.f.; peacock, d.g. coulson and richardson's chemical engineering, vol. 3, 3rd ed., butterworth-heinemann, oxford (2007). 10. rodrigues, a.e., levan, m.d.; tondeur, d. adsorption: science and technology, springer, netherlands (2011). 11. holland, c.d.; liapis, a.i. computer methods for solving dynamic separation problems, mcgrawhill, new york (1983). 12. banerjee, r., narayankhedkar, k.g.; sukhatme, s.p. exergy analysis of pressure swing adsorption processes for air separation, „chem. eng. sci.", 45, 467 (1990). 13. farooq, s., ruthven, d.m.; boniface, h.a. numerical simulation of a pressure swing adsorption oxygen unit, „chem. eng. sci.", 44, 2809 (1989). 14. farooq, s., hassan, m.m.; ruthven, d.m. heat effects in pressure swing adsorption systems, „chem. eng. sci.", 43, 1017 (1988). 15. yang, r.t.; cen, p.l. improved pressure swing adsorption processes for gas separation, „ind. eng. chem. process des. dev.", 25, 54 (1986). 16. bequette, b.w. process dynamics: modeling, analysis and simulation, prentice hall, new jersey (1998). 17. pontikakis, g., papadimitriou, c.; stamatelos, a. kinetic parameter estimation by standard optimization methods in catalytic converter modeling, „chem. eng. comm.", 191, 1473 (2004). 18. kasser, n.w. dynamic behavior of non-isothermal multi-component adsorption in adiabatic fixed bed, ph.d. thesis, university of baghdad (1997). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 267 taguchi method to optimize machining conditions affecting cemented carbide tool's wear life in turning aisi 1020 steel kawthar y. al-dulaimi 1 , dr. haydar a. h. al-ethari 2 , bogdanwarcholinski 3 1(msc. student at dept. of metallurgical eng., college of material's eng university of babylon-hilla-iraq) 2(prof. at dept. of metallurgical eng., college of material's eng university of babylon-hilla-iraq) 3(prof. at koszalin university of technologypoland) received 27december 2015 accepted 21 january 2016 abstract: the present work studied the performance of a carbide tool with a chemical composition of (65% w, 14 % ti, 9 % co and 12 % c). turning tests were conducted on a workpiece of mild steel (aisi 1020) using four spindle speeds (80, 315, 500 and 800 rpm), two feed rates (0.2 and 0.5 mm/rev) and two depth of cut (0.5 and 0.7 mm). taguchi method is a statistical approach to optimize the process parameters and improve the quality of components that are manufactured. the objective of this study is using taguchi method to optimize the machining conditions of a turning operation such as spindle speed; feed rate and depth of cut. orthogonal array, signal-to-noise ratio, and analysis of variance were employed using mtb14 software to study the performance characteristics on turning operation represented by the tool life. accordingly, a suitable mixed orthogonal array l16 (3×4) was selected. the tool life was measured basing on a maximum flank wear width of 0.3 mm.optimum parameter values were obtained and confirmation experiments were carried out. the analysis results showed that the parameter design of the taguchi method provides a simple, systematic, and efficient methodology for optimizing the process parameters. only 6.4 % error was recorded. the regression analysis was applied using datafit ver.9 software. the results of the analysis showed that the non-linear quadratic polynomial appears to be more suitable to represent the relation of the spindle speed, feed rate and depth of cut with the tool's wear life. . key words: tool life, machining parameters, taguchi method, flank wear, optimization, modeling. طريقة تاكوجي ألمثلية طرق التشغيل المؤثرة على عمر البلى للعدد الكاربيدية المسمنتة في (aisi 1020خراطة الفوالذ) الخالصة: ( . w, 14 %ti, 9 % co and 12 % c %65) ترك ل ك م لي ي رمنلم العمل الاليلي رل أد ء ال العل ك الييأة رل ,500 ,315 ,80)ةيسلمعمي اأةعل سلرو أا ل (aisi 1020)اخمبيأات الخراط ق اجررت علل شغللةل شل ذلةط ش للي al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 268 طررق تليكةجي ( شلم .( and 0.7 0.5شلم/ أك , ق مم لعمق الق ع (and 0.5 0.2) أك/ ق ق , ق م م لمع الملذر ( 800 عمل تاس ةع المركبيت المصنع . ه ف هذه ال أاس هة تةض ح األجلرال المسلمعم هي شنهج إحصي ي لماس شا ات ال . شثلل السللرع ال أا لل , شعلل الملذرلل عمللق الق للع ذللي اسللمخ اي طررقلل تلليكةجي لماسلل يللر ف المغللل ذللي عمل لل الخراطلل ل أاسل شم لتات اط اك ذلي mtb 14ممعيش ك , سب األشيأك ال النةضيل تال المبلير قل تلم اسلمخ اشهي ةمسلمعمي المصفةذ ال قل تلم اخم يأهلي. عملر العل ك قل تلم l16 (3×4). ذقيً لذلك , شصفةذ شمعيش ك شخمل ل شنيسلب مل الخراط شممثل ةعمر اط اكع . الظر ف المثل ق تم الاصلة عل هلي اخمبليأات الماقلق قل تلم (mm 0.3)لةصي اطقص ق يسه اعممي ا عل عرض البل الخ تنف ذهي . تال النمي ج المجررب ايهرت ءن تصم م المعلم ة ررقل تليكةجي د ت طررقل ةسل , شنهج ل ذعيلل لجعل يلر ف اضيذمه ةيسمعمي ةر ليشج اتيذلت النسلخ الميسلع . ملي ج هلذا . تال المراجع ق تم سب خ م ق سجلت % 6.4العمل شثيل . ذقط المال ايهرت ان الممع الا ش ال أج الثي ل ي لر الخ لي هلة اكثلر شل مل لممث ل العلقل ةل السلرع ال أا ل , شعل . . الملذرللللللللللللللللللللل عملللللللللللللللللللللق الق لللللللللللللللللللللع شلللللللللللللللللللللع عملللللللللللللللللللللر األ اك 1. introduction: the tool is an important part required in material removal process in order to produce the components. it not only provides product but also maintains the geometricaltolerances, dimensional accuracies and surface finish of the outcome. the manufacturing industry is striving to improve the productivity, quality and longer tool life. achievement of longer tool life depends on different factors such as cutting parameters, tool wear, hardness of the work piece and machine tool materials [1,2]. many improvements can be done to obtain longer tool life duration like changing the tool material, tool geometry, tool edge honing, optimizing machining conditions, using coolants and applying thin layer coating. tool wear influences cutting power, machining quality, tool life and machining cost. whentool wear reaches a certain value, variation in cutting force and cutting temperature will causesurface integrity deteriorated and dimension error greater than tolerance. when machining steel with uncoated carbide tools, different tool wear mechanisms occur, such as: abrasion, adhesion, oxidation and even some diffusion, which act simultaneously and mainly depending on the temperature [3,4]. bala murugan gopalsamy et al. in 2009 [5] applied taguchi method and analysis of variance anova for machining parameters optimization during machining hardened steel. anova, signal-to-noise ratio, and l18 array had been used to study the performance characteristics of the machining conditions ( feed rate, cutting speed and depth of cut ) with consideration of tool life and surface roughness. s.r. das et al. in 2014 [6] experimentally investigated the effects of the machining conditions on the behaviour characteristics (surface roughness, cutting force and flank wear) by using multi layer coated carbide insert in hard turning of aisi 4340 steel. taguchi standard has been used to develop the regression models for machining response. results showed that, the most significant factor on flank wear is the cutting speed and that the feed rate has statistical significance on the surface roughness. the objective of the present work is studying the optimization process of the machining conditions that affecting the tool wear. basing on the analyses of multiple regression method, mathematical predictive model was designed and validated to select an optimum combination of the studied parameters.taguchi design is successfully used for optimizing the cutting conditions that affecting tool life. to achieve the analysis of the present work, datafit ver9 and mtb14 softwares had been employed. 2. experimental procedure : 2.1. materials used : 2.1.1. carbide tool (tip): carbide tips type p10 with a chemical composition of (65% w, 14 % ti, 9 % co and 12 % c) were used in this investigation. the tip has a tool angle of 60 o and a nose radius of 1.6 mm. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 269 2..1.2. workpiece material : the machining experiments were performed using cylindrical work-piece of aisi 1020 steel with a chemical composition demonstrated in table (1). the tests were carried out for a length of (210 mm) and (40 mm) diameter. this kind of steel is the most common form of steel because it’s price is somewhat low while it offers material characteristic that are tolerable for many applications. 2.2. description of turning process: in this work, external longitudinal turning operation was used for machining experiments. the 210 mm length and 40 mm diameter low carbon steel bar was divided into working regions of 50mm length as shown in fig.(1). for all machining experiments, dry cutting condition was used. four spindle speed (80, 315, 500, and 800 rpm) for each of which two feed rates 0.2 and 0.5 mm/rev and two values for the depth of cut (0.5 and 0.7 mm) were used. the inserts used were rigidly mounted on a tool holder type (tak holder). 2.3. tests ( material testing) or flank wear : a maximum width of 300 µm for the flank wear was considered as a criterion for the tool life. the width of the flank wear was measured every one minute of machining. optical microscope type (electron eyepiece, model yjeye01, resolution of 1280(h)*1024(v), china) integrated with ccd camera was used to capture the image of worn tools and to measure the flank wear width. 3. results and discussion: table (2) demonstrate the results of the machining experiments according to the used machining program. figure (2) represent examples for the method used in estimating the tool life. these figures shows the typical behavior of the flank wear width (vb) with the machining time. an accelerated increase of vb can be noticed with the machining process at the first stage of cutting, then a constant rate of this increase at the second stage, after which a very rapid increase at the third stage that will continue till premature failure of the tool. the figures also indicate that a higher cutting speed causes a higher value of vb. this is due to the increase in cutting temperature accompanying with the increase in cutting speed and this causes increase in adhesion wear on tool cutting edge, also the increase in temperature may soften a very thin surface layer of the tool cutting edge. in addition to that a higher cutting speed means a higher repeated contact between the machined surface and the flank surface which increases the scratching action of machined material (i.e. the abrasive wear). figure (3) shows examples of the wear occurred at the flank surface of the tool during. both fundamental and empirical approaches can be used to establish models or equations for quantitatively predicting the cutting performance such as tool life and surface roughness. in the case of the empirical approach, the machining characteristic values which experimentally measured (tool life) are related to the cutting conditions by regression analysis. several forms of mathematical models, as linear, exponential, power function, and nonlinear quadratic polynomial were used to exam the approach. .4. development of mathematical predictive model: mathematical predictive models for the tool life had been developed in forms shown in table (3). such models were constructed basing on the statistical data of the carried out machining experiments. data fit ver.9 software was used for constructing these models basing on multiple al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 270 regression analyses. the value of the coefficient of multiple determination (r 2 ) for the non-linear quadratic polynomial is highest rank among all forms of other models. hence, this model is selected to predict value of tool life. so the final mathematical predictive model developed will be: t=2.3931+5.5524x1+13.4310x2+13.3856x3+8.6831x1 2 +10.9889x2 2 +6.6217x3 2 +7.2496x1x2 +10.3714x2x3 +4.0852x1x3+8.7428x1x2x3 (1) where: t = tool life (min.); x1= spindle speed (rpm); x2= feed rate (mm/rev.), and x3= depth of cut (mm). fig.(4) shows the matching between the experimental values of the tool life and their predicted values due to the designed models. the figure indicates their close matching. 5.taguchi approach : 5.1. selection of control factors and noise factors: cutting speed, feed rate, and depth of cut have a significant influence on tool life in the turning operations, so they were considered as the controllable factors in this study, while tool life as response factor as shown in table (4). design of experiments via taguchi method and l16 (3×4) mixed orthogonal array is utilized for the parametric design [7,8,9]. to obtain optimal cutting conditions, the larger-the-better is used as s/n ratio of quality characteristic. this expressed as [10]: where: η = signal to noise ratio (s/n), yi = observed value of the response, n = number of observation in a trial. table (5) shows the experimental results and the corresponding s/n for tool life. table (6) shows the response values for signalto-noise ratios and the response values formeans for tool life. figure (5) shows the results of taguchi design analysis (main effect plot for means and main effect plots for s/n ratio) for tool life. also, taguchi orthogonal array is demonstrated in table (5). figure (5) indicate that the optimal machining conditions representing the conditions at which the tool life will be maximum are: spindle speed, vc =315 rpm, feed rate, f= 0.4 mm/rev, and depth of cut, t= 0.6 mm. 5.2. analysis of variance anova: determining which machining parameter significantly affect the quality characteristic (tool life) is the main purpose of anova. this can be done by separating the total mean s/n ratio from the total variability of the s/n ratios which is determined by sum of square deviations. first, the total mean s/n ratio ηm from the total sum of squared deviations sst can be calculated as : i= 1, 2, … n (2) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 271 ∑ ( ) (3) where ηi is the mean s/n ratio for the i th experiment and n is the number of experiment in the orthogonal array. table (7) shows the anova (with 95% confidence level) and f-test values with the pvalue which reflects effectiveness of the individual studied parameters on the tool life. the table indicates that the feed rate is the most significant parameter for maximum tool life. 5.3. predicting optimum performance : the optimum tool life can be predicted by using the designed model (eq. 2) based on the determined optimum cutting conditions (i.e. at vc = 315 rpm, f = 0.4 mm/rev., and t = 0.6 mm) at which the tool life equals to 7.8 min. 5.4. confirmation of the optimum results: the purpose of the confirmation experiment in this study was to validate the optimum cutting conditions. the predicted tool life was calculated basing on the optimum machining conditions resulted by taguchi analysis. also basing on these machining conditions, experimental values for tool life were measured. table (8) shows the comparison of the actual tool life with the predicted tool life using optimal cutting parameters for the used inserts with an error percentage of 6.4 % for tool life. 6. conclusions: in this study, the taguchi method was used to predict the most turning conditions of the aisi 1020 steel affecting the cemented carbide tool life, according to the results obtained, the following points can be concluded: 1-the taguchi method is a robust orthogonal array design method, suitable for analysis of the tool machining parameters have an effect on the tool life. among these parameters feed rate has the largest effect on the tool life. 2multiple regression analysis can be applied to develop a mathematical model for tool life prediction. the models developed are found to be reliable. an assessment of turning of aisi 1020 steel can be achieved by the designed empirical model for selecting the appropriate machining conditions for a required carbide tool life. 3an optimum machining combination of aisi 1020 steel for maximum tool life is spindle speed of 315 rpm, feed rate of 0.4 mm/rev., and depth of cut of 0.6 mm. 7. references: [1] m. narasimha, d. tewodros, r. rejikumar, improving wear resistance of cutting tool by coating, iosr journal of engineering (iosrjen) , vol. 04, issue 05 (may. 2014), pp (06-14). [2] b. fnides, s. boutabba, m. fnides, h. aouici, m. a. yallese, cutting tools flank wear and productivity investigation in straight turning of x38crmov5-1 (50 hrc), international journal of applied engineering and technology, 2013, vol. 3 (1) january-march, pp (1-10). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 272 [3] bin li, a review of tool wear estimation using theoretical analysis and numerical simulation technologies, int. journal of refractory metals and hard materials 35, 2012, pp (143– 151). [4] abdul kareem jaleel, kareem abdulla hadi, coated carbide cutting tools performance in high speed machining processes, the iraqi journal for mechanical and materials engineering, vol.12, no.1, 2012. [5] bala murugan gopalsamy, biswanathmondal and sukamal ghosh, taguchi method and anova: an approach for process parameter optimization of hard machining while machining hardened steel, journal of scientific and industrial research vol. 68, august 2009, pp(686-695). [6] s. r. das1, r.p. nayak, d. dhupal, a. kumar, surface roughness, machining force and flank wear in turning of hardened aisi 4340 steel with coated carbide insert: cutting parameters effects, international journal of automotive engineering vol. 4, number 3, sept 2014. [7] rajesh nayak, raviraj shetty, sawan shetty, investigation of cutting force in elastomer machining using taguchi’s design of experiments”, international journal of advanced technology & engineering research (ijater), ,volume 4, issue 4, july 2014. [8] roy ranjit k, design of experiments using the taguchi approach : 16 steps to product and process improvement, john wiley & sons, inc. (us),2001. [9] haydar a. h. al-ethari, kadhim finteel alsultani, nesreen dakhel f., optimization of chemical machining conditions of cold worked stainless steel 420 using taguchi method, international journal of mechanical engineering and technology (ijmet), volume 5, issue 3, march (2014), pp (57-65). [10] genichi taguchi, subir chowdhury, yuin wu,taguchi’s quality engineering handbook, 2005 john wiley & sons, inc., hoboken, new jersey. table (1): chemical composition of the workpiece material (wt %). c si mn p s cr mo ni al co cu fe 0.15 6 0.004 8 0.38 6 0.018 1 0.020 0 0.024 8 0.005 1 0.017 6 0.007 7 0.015 7 0.01 39 99.3 (balance) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 273 table (2) : results of machining experiment for the used tool. table (3) : predictive models for the tool life. no.no. vc (rpm) f (mm/rev) t (mm) t (min) s/n ratio 1 1 1 1 3.6 11.1261 2 1 2 2 4 12.0412 3 1 3 3 3.8 17.9525 4 1 4 4 3.8 11.5957 5 2 1 2 3 9.5424 6 2 2 1 3.9 11.8213 7 2 3 4 2.7 8.6273 8 2 4 3 2.9 11.1261 9 3 1 3 2.4 12.0412 10 3 2 4 2.8 15.563 11 3 3 1 2.2 19.0849 12 3 4 2 2.2 13.9794 13 4 1 4 1.9 13.0643 14 4 2 3 2.1 13.9794 15 4 3 2 1.4 13.2552 16 4 4 1 1.5 18.0618 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 274 table (4) :parameters and levels for experimental design. parameter symbol unit level 1 level 2 level 3 level 4 spindle speed x1 rpm 80 315 500 800 feed rate x2 mm/rev 0.2 0.3 0.4 0.5 depth of cut x3 mm 0.5 0.6 0.7 0.8 table (5): experimental results and the corresponding s/n for tool life. table (6) : response values for signalto-noise ratios and the response values for means. response values for signal to noise ratios (larger is better) response values for means level vc f t level vc f t 1 13.90 11.57 11.72 1 5.325 4.038 4.506 2 14.65 15.49 15.63 2 5.831 6.300 6.288 3 14.01 16.39 12.98 3 5.613 6.900 5.138 4 12.58 11.69 14.81 4 4.919 4.450 5.756 delta 2.07 4.82 3.92 delta 0.912 2.863 1.781 rank 3 1 2 rank 3 1 2 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 275 table (7) : one way anova results. t versus vc t versus f t versus t source df ss ms f p source df ss ms f p source df ss ms f p vc 3 7.46 2.49 0.46 0.709 f 3 93.07 31.02 7.88 0.00 t 3 28.49 9.50 1.89 0.140 error 12 321.89 5.36 error 12 236.28 3.94 error 12 300.86 5.01 total 15 329.35 total 15 329.35 total 15 329.35 *df – degree of freedom, ss : sum of squares, ms : mean square, p: probability. table (8) : confirmation test results for the used insert. figure (1) : workpiece regions. performance predicted experimental error% tool life (min) 7.8 7.3 6.4 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 276 figure(2): estimation of the tool life. 0 100 200 300 400 500 0 1 2 3 4 5 w id th o f fl a n k w e a r ,v b (m ic ro ) cutting time ,(min). feed rate =0.2 mm/rev doc = 0.5 mm 80 rpm 315 rpm 500 rpm 800 rpm 0 100 200 300 400 500 0 1 2 3 4 5 w id th o f fl a n k w e a r, v b (m ic ro ) cutting time,(min) feed rate =0.5 mm/rev doc = 0.5 mm 800 rpm 500 rpm 315 rpm 80 rpm 0 100 200 300 400 500 0 1 2 3 4 5 w id th o f fl a n k w e a r ,v b (m ic ro ) cutting time ,(min). feed rate =0.2 mm/rev doc = 0.7 mm 800 rpm 500 rpm 315 rpm 80 rpm vb max 0 100 200 300 400 500 0 1 2 3 4 5 w id th o f f la n k w e a r, v b (m ic ro ) cutting time ,(min) feed rate = 0.5 mm/rev doc = 0.7 mm 80 rpm 315 rpm 500 rpm 800 rpm al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 277 figure (3) : the flank wear of the tools during the machining process. spindle speed= 80 rpm spindle speed= 315 rpm spindle speed= 315 rpm spindle speed= 315 rpm spindle speed= 315 rpm spindle speed= 500 rpm spindle speed= 500 rpm spindle speed= 500 rpm spindle speed= 500 rpm spindle speed= 800 rpm spindle speed= 800 rpm spindle speed= 800 rpm spindle speed= 800 rpm spindle speed= 80 rpm spindle speed= 80 rpm spindle speed= 80 rpm al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 278 fig.(4): scatter plot of the experimental and predicted values of tool life. fig.(5): results of taguchi design analysis: (a) main effect plot for means; (b)main effect plots for s/n ratio for tool life. 0 1 2 3 4 5 6 0 1 2 3 4 5 6 p re d ic te d t o o l li fe ( m in ) measured tool life (min) tool material : p 10 workpiece : aisi 1020 cutting parameters : vc=(80, 315, 500 ,800 rpm), feed rate (0.2 and 0.5 mm/rev) and depth of cut (0.5 and 0.7 mm). article al-qadisiyah journal for engineering sciences 12 (2019) 225–231 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohanad.shallal@qu.edu.iq ( muhaned a. shallal) https://doi.org/10.30772/qjes.v12i4.639 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. push-out tests for determining shear strength and stiffness of perfobond connector-experimental study khawla a. farhan a and muhaned a. shallal a* a civil engineering department, college of engineering, university of al-qadisiyah a r t i c l e i n f o article history: received 03 october 2019 received in revised form 14 november 2019 accepted 21 november 2019 keywords: concrete-filled steel tube (cfst) lightweight concrete push-out test perfobond connector reinforced concrete compressive strength a b s t r a c t this study presents an experimental investigation for push-out tests in order to evaluate the performance of continuous perfobond connectors. a total of five specimens composed of light-weight concrete-filled steel tubes (square and circle sections) with two reinforced blocks were tested. the measured parameters are the compressive strength of the concrete blocks and the type of the section. the specimens were tested under a concentric load applied on the steel tube filled with lightweight concrete; the corresponding slip value was measured using two lvdts. the experimental results showed that the ultimate shear strength and stiffness of the square steel tube filled with concrete were higher than that of circular samples. the ultimate shear strength and stiffness increased with an increase of concrete compressive strength, while the corresponding slips showed decreasing in their values with increase of the compressive strength of the concrete. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the most important feature for design the composite structure is a loadslip relationship because it is going to set the linear and nonlinear behavior of the shear connection. the push-out tests are a very appropriate way to determine this relationship. the earlier studies were focused on the stud connectors, with different diameters, lengths, and spaces between the connectors. there are some proposed expressions to predict the load-slip relationship for the stud connector [1-3]. many types of connectors are available such as perfobond ribs, oscillating perfobond strip shear connector, corrugated shear connector waveformstrip shear connector, and perfobond connector, as shown in fig. 1. the perfobond connector can be used in several applications such as connecting the cfst (concrete filed steel tube) members with concrete beam, foundation or slab, as shown in fig. 2. three-stages in the curve of the loadslip of perfobond connector for push out test usually obtained, as shown in fig. 3 [4]. the initial stage is elastic in which the loading followed the linear elastic relationship untill the initial slip (si) of perfobond connector and the equivalent load was the yield strength (vy). the shear stiffness ks of perfobond connector is equal to (vy/si). the second stage is the elasto-plasto stage in which the shear load increases until the ultimate load (peak point) is reached. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 226 khawla farhan and muhaned shallal /al-qadisiyah journal for engineering sciences 12 (2019) 225–231 at this stage the maximum load is known as ultimate shear strength and the equivalent slip is known as the ultimate slip. the last stage is the post failure stage, which appears after the ultimate shear strength is obtained. beyond the ultimate shear strength, the slip shows continues, while the shear load v tends to decrease. many studies have been conducted to investigate the performance of perfobond connector. also, some expressions were suggested to expect the load slip relation for different types of perfobond connectors. zheng et al. [6] were testing seventy-two samples to get the performances of perfobond connectors using push-out tests. the tested parameters were the actions of using different strengths of very long sentences: concrete such as, varying the hole geometry, the arrangement of the reinforcement in holes, the size of the concrete slab, and the dimensions of the perfobond rib. an appropriate model was proposed to definite perfobond connector load–slip relationship casing a wide range of design parameters. (a) perfobond ribs (b) corrugated perfobond strip (c) oscillatingperfobond strip (d) waveform-strip figure 1. types of perfobond shear connectors [5]. (a) strengthening of the pile cap (b) composite trusses. figure 2. perfobond connectors [6]. figure 3. stage identifications [4] oguejiofort and hosain [7] carried out a numerical study for the behavior of the perfobond connector using the finite element technique. the main nomenclature cp specific heat (j kg-1 k-1) greek symbols g gravitational acceleration (m s-2)  thermal diffusivity (m2 s-1) k thermal conductivity (w m-1 k-1)  thermal expansion coefficient (k -1) kr thermal conductivity ratio, kr = kw/kf  solid volume fraction l length of the enclosure (m) ɵ dimensionless temperature lb baffle length (m) ø baffle inclination angle nul local nusselt number along with the heat source µ dynamic viscosity (kg m-1s-1) nu average nusselt number p pressure (kg m-1 s-2) subscripts p non-dimensional pressure av average pr prandtl number b baffle ra rayleigh number c cold t dimensional temperature f fluid (pure water) u non-dimensional velocity component x-direction h hot y non-dimensional y-coordinates w wall khawla farhan and muhaned shallal /al-qadisiyah journal for engineering sciences 12 (2019) 225–231 227 purpose of this study was to find the ultimate capacity of the perfobond connector. it was noticed that the predicted capacities gotten by the equations resulting from the numerical study were in a good arrangement when compared with the investigational results of the push-out test. ahn et al. [8] studied the behavior of the single and twin perfobond connectors. they described the perfobond connector between the high-strength concrete beam and steel section. push out test has been conducted for this connector and study the effects of changing the strength of the concrete, the existence of transverse reinforcement in the holes of the connector, concrete end-bearing zone, and the arrangement of perfobond connector. shear strength was measured through push out test. the main purpose of the study is to find the best arrangement of the perfobond connector and optimum design of the shear connector to use in the design of the concrete-steel girder system. the results obtained were compared with other studies and with shear capacity equations derived from the numerical studies. from the results, the equations that take into account the perfobond ribs arrangement derived and compared with prior equations. the comparison between the values found for single perfobond connector with transverse reinforcement were underestimated, but for twin perfobond connector the values were overestimated and so an improved shear capacity equation was proposed based on the analysis of the result. zheng. et al. [9] presented a study on the ultimate shear capacity of perfobond shear connector. the researchers tested twenty-one samples. the major goal was to find a shear capacity, shape of failure, and slip performance of perfobond connectors. eighty-seven numerical models were done to additional study the effects of concrete strength and hole shape. the parametric consequences created to calculate the equations of shear strength for perfobond connectors. finally, an analytical model proposed to predict the shear capacity of both long and circular hole of perfobond connectors. this model depended on a hole size, transverse bar area, concrete strength and yield strength of the transverse bar. su and wang [10] developed a new type of connector used in a composite structure. they used a corrugated connector and tested it using a push-out test. they found that the performance of the corrugated connector was very good. the researchers compared with the properties of perfobond connector that gained from the push-out test. shear capacity of corrugated connector was higher than that of perfobond connector by 24 percent. the stiffness of the corrugated connector was higher than of the perfobond connector. the load-slip curve of the corrugated connector was found using push-out tests. relative stiffness expressions under the ultimate capacity and service state can also computed these tests. li et al. [11] investigated the load-slip performance and failure characteristics for corrugated connector by pushout test and numerical technic. the results indicated that the shear strength of corrugated connector was affected by several factors such as the strength of concrete, perfobond reinforcement yield strength, the open area of steel plate, cross-sectional area, and horizontal projection area of corrugated connector. the concrete shear stiffness bars effect on the shear stiffness of corrugated connector in the elastic stage. a new mixed type of combined connectors was suggested by zheng et al. [12]. the researchers used a stud connector with perfobond connector together. they designed nine specimens and tested them. a comparison between studs, perfobond connector, and the mixed connector in shear strength and the load-slip performance was performed. furthermore, numerical models were produced to study additional the performances of combined shear connectors relating to material properties and connector dimension. they concluded that the shear capacity of the mixed shear connector increase with increasing rebar diameter, stud size, stud properties, hole diameter, concrete strength, and rebar properties. the curves of the load slip relationship that gained from finite element study were close to the tested results. ibrahim et al. [13] conducted an experimental study on the shear. four groups were formulated and tested under twelve push-out tests. these groups consisted of three types of shear connectors (stud, angle, and perfobond connectors). the researchers studied the behavior of shear connector, calculating the stiffness, and shear strength of these connectors. the results were concentrated on failure modes, strength, load-slip curves, and stiffness of the connectors. the results obtained showed very close behavior (shear resistance and stiffness) between ishape and circular tube when using studs in two sections but the shear capacity of the perfobond connector higher than the shear capacity of the stud and angle connector. zheng et al. [14] proposed an alternative notched perfobond connector to make it easy for installation of perforating reinforcement bars, because of difficulties of perforating the rebar inside the holes of classic perfobond connector with multi-ribs in bridges. this study showed the result of the push-out test for six samples which tested to failure. the major objective was to comparing between the behavior of perfobond connector with circular holes and the perfobond connector with notched holes in terms of shear capacity, slip behavior and failure mode. also, forty-three nonlinear simulations were performed to study some variables and their effects like hole distance, hole number, hole diameter, rebar diameter, steel strength, and rebar strength. the final analytical model was proposed to calculate the shear strength of perfobond connector. the relationship between the slip and horizontal shear resistance in perfobond connectors depending on the number of perfobond connectors and the reinforcement bar properties that used in the holes of the perfobond connector. this study used a continues perfobond connector with a concrete-filled steel tube (cfst) to investigate the effect of bars in a connector only. the concrete used for filling the steel tube is lightweight. three different mixes were used to understand the effect of concrete compressive strength used in concrete blocks on the slip; also, the two-section type used of cfst. 2. experimental program five samples were prepared for testing push out behavior. each sample consists of a concrete-filled steel tube of 500 mm length and two reinforced concrete blocks of 500×450×75mm. a lightweight concrete mixture was used to fill the steel tube. the details of the tested samples are listed in table 1. the samples were named as two sections, s or c appointed to the section type of steel tube, s means square, and c means circular. the strength of concrete blocks was marked next to former notions as (55, 45, and 35 mpa). the samples were connected with both sides to concrete block by perfobond connector, as shown in fig. 4. perfobond connector with dimensions 450×50×8 mm has holes with a diameter of 10 mm, which used to pass the steel reinforcement bar for each section. the strength of infill concrete in tubes was the same lightweight concretefor all samples. two (lvdt) were used one on each block to record the slip between the steel tube and the concrete block. the arrangement of this test was according to eurocode 4 [15]. 3. material properties three types of normal concrete were used for concrete blocks and one lightweight concrete mix was used in cfst. the concrete-filled in tubes was a lightweight concrete formulated using gravel with a maximum size 228 khawla farhan and muhaned shallal /al-qadisiyah journal for engineering sciences 12 (2019) 225–231 of 1.0 cm as check it (leca). details of concrete mixtures, density, and cubic compressive strength are listed in table 2. the values of yield stress and ultimate strength of the steel reinforcement, steel tubes, and perfobond connector are summarized in table 3. table 1. details of specimens compressive strength (mpa) section type specimen cfst concrete block 20 35 square s-35 20 45 square s-45 20 55 square s-55 20 35 circular c-35 20 55 circular c-55 table 2. properties of mixing concrete mixing ratio (w/c) ratio s. p fcu (n/mm2) density (kg/m3) lwc=20 1:1.744:0.5 0.3 1% 21.85 1790 m2=55 1:1.47:2.2 0.3 0.5% 52.17 2518 m3=45 1:1.89:2.84 0.4 0.3% 47.93 2340 m4=35 1:2.67:4 0.5 35.14 2250 table 3 steel properties. component fy (mpa) fu (mpa) square tube 390 433 circular tube 305 391 steel reinforcement bar 464 606 perfobond connector 357 370 figure 4. specimen details. khawla farhan and muhaned shallal /al-qadisiyah journal for engineering sciences 12 (2019) 225–231 229 4. testing procedure the load applied with increases of 5 kn; the procedure of investigation was in agreement with eurocode 4 [15]. for all tested samples two of lvdts were used to record the displacement between concrete blocks and cfst; the locations of lvdts, as shown in fig. 5. figure 5 slipping test 5. results and discussions the results obtained from the tests are listed in table 4. the load-slip relation of all samples is shown in fig. 6. the tests were continued until the sample is completely failed. there were two signs of failure, the first is the appearance of a longitudinal crack parallel to the perfobond connector and the second is crushing in both concrete blocks, as shown in fig. 7. for knowing what happens for reinforcement bars that used in the connectors, the concrete in both blocks was removed. after the extraction of reinforcement bars, it was found that some reinforcement had cut and the other had a very large deformation, as shown in fig. 8. table 4. result of the push-out test specimen vu (kn) vy (kn) si (mm) sp (mm) ks (kn/mm) s-55 608.34 347.89 0.916 6.83 379.79 s-45 575.2 325.98 0.993 8.16 328.28 s-35 558.32 301.72 1.95 10.43 154.72 c-55 590.27 325.98 1.393 8.19 234.01 c-35 541.50 272.50 1.549 9.99 175.92 figure 6 load-slip relation for all specimens. figure 7 the failure mode of specimens. figure 8 deformation of reinforcement bars. one of the parameters of the study was observing the effect of concrete compressive strength. fig. 9. shows the effect of compressive strength on load-deflection curves for samples of square cfst and circular cfst. from table 4 and fig. 9. the ultimate shear strength of specimens s-55, s-45, and s-35 were 608.34, 575.2, and 558.32 kn respectively. from these results, it can conclude that the ultimate shear strength increases with an increase of concrete compressive strength. however, the maximum slip decreased with an increase in the compressive strength of concrete. the maximum slip of these specimens (s-55, s-45, and s-35) was 6.83, 8.16, and 10.43 mm, respectively. the stiffness of the elastic stage (ks) listed in table 4. the stiffness of specimens s-55, s-45, and s35 were 379.79, 328.28, and 154.72 kn/mm respectively. the stiffness increased with the increase of the compressive strength of concrete. the same behavior is shown for specimens c-55, c-35, ultimate shear strength was 590.27 and 540.40 kn for c-55, c-35, respectively. while the stiffness of these specimens were 234.01 and 175.92 kn/mm, respectively. it can be concluded that by increasing the compressive strength of concrete, both of ultimate shear strength and stiffness of the samples are increased. section type cfst was the major parameter of the study. fig. 10. shows the load-slip relation of perfobond connectors influenced by section type cfst. from fig. 10. and table 4 it can be noticed that the sample of circular section c-55 has ultimate shear strength less than that of the sample with square section s-35 at 590.27 kn and 608.34 kn respectively. the stiffness values of these samples were 379.79 and 234.01 kn/mm, respectively. for other samples with 35 mpa compressive strength it was also noted that the specimen of circular section c-35 has ultimate shear strength 540.40 kn, which was less than the specimen of square section s-35 that has 558.32 kn. nevertheless, note the stiffness of these specimens showed a different behavior where the stiffness decreases despite increasing the ultimate shear strength. 230 khawla farhan and muhaned shallal /al-qadisiyah journal for engineering sciences 12 (2019) 225–231 (a) square cfst (b) circular cfst figure 9 effect of concrete compressive strength. (a) specimens of 35 mpa compressive strength. (b) specimens of 55 mpa compressive strength. figure 10 effect of cfst section type. 6. conclusion the followings are the most important concluding remarks from the experimental work conducted in this study: 1. for the samples have a square cfst, the ultimate shear strength of the tested samples reduced by 5.44% when a concrete compressive strength of the blocks decreased from 55 to 45 mpa. while more decrease of 8.22% was recorded when the compressive strength was decreased further to 35 mpa. 2. for the samples have a circular cfst, the ultimate shear strength of the tested specimens reduced by 8.26% when a concrete compressive strength of the blocks decreased from 55 to 35 mpa 3. the sample with a square steel tube exhibited higher ultimate shear strength and stiffness than the sample with a circular steel tube. 4. the stiffness of the tested samples reduced by 13.56 % when the concrete compressive strength of the blocks decreased from 55 to 45 mpa. while a more decrease of 59.26 % recorded when the compressive strength decreased further to 35 mpa, for the samples have a square cfst. 5. the stiffness values of the tested samples reduced by 24.82 % when the concrete compressive strength of the blocks decreased from 55 to 35 mpa, for the samples have a circular cfst. 6. in general, when the concrete compressive strength increased, the maximum slip is reduced. for the samples have a square khawla farhan and muhaned shallal /al-qadisiyah journal for engineering sciences 12 (2019) 225–231 231 cfst, the maximum slip was 6.83, 8.66, and 10.93 mm when the concrete compressive strength was 55, 45, and 35 mpa, respectively. while for the samples have a circular cfst, the maximum slip was 8.19 and 9.99 mm when the concrete compressive strength was 55 and 35 mpa, respectively. references [1] w. lorenc and e. kubica, ‘behavior of composite beams prestressed with external tendons: experimental study’, journal of constructional steel research, vol. 62, no. 12, pp. 1353–1366, dec. 2006. [2] w. xue, m. ding, h. wang, and z. luo, ‘static behavior and theoretical model of stud shear connectors’, journal of bridge engineering, vol. 13, no. 6, pp. 623–634, nov. 2008. [3] a. prakash, n. anandavalli, c. k. madheswaran, and n. lakshmanan, ‘modified push-out tests for determining shear strength and stiffness of hss stud connector-experimental study’, international journal of composite materials, vol. 2, no. 3, pp. 22–31, aug. 2012. [4] ‘analytical model for load–slip relationship of perfobond shear connector based on push-out test’. [online]. available: https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6337733/. [accessed: 11mar-2019]. [5] ali shariati, ‘various types of shear connectors in composite structures: a review’, international journal of the physical sciences, vol. 7, no. 22, jun. 2012. [6] s. zheng, c. zhao, and y. liu, ‘analytical model for load–slip relationship of perfobond shear connector based on push-out test’, materials, vol. 12, no. 1, p. 29, dec. 2018. [7] e. c. oguejiofor and m. u. hosain, ‘numerical analysis of push-out specimens with perfobond rib connectors’, computers & structures, vol. 62, no. 4, pp. 617–624, feb. 1997. [8] j.-h. ahn, c.-g. lee, j.-h. won, and s.-h. kim, ‘shear resistance of the perfobond-rib shear connector depending on concrete strength and rib arrangement’, journal of constructional steel research, vol. 66, no. 10, pp. 1295–1307, oct. 2010. [9] s. zheng, y. liu, t. yoda, and w. lin, ‘parametric study on shear capacity of circular-hole and long-hole perfobond shear connector’, journal of constructional steel research, vol. 117, pp. 64–80, feb. 2016. [10] q. t. su and d. f. wang, ‘strength and stiffness of corrugated rib connector’, advanced materials research, vol. 243–249, pp. 1497–1503, may 2011. [11] s. li, l. su, and z. sun, ‘research on the load-slip properties of corrugated rib connectors’ push-out test’, ksce journal of civil engineering, vol. 22, no. 4, pp. 1258–1264, apr. 2018. [12] s. zheng, c. zhao, and y. liu, ‘parametric push-out analysis on perfobond rib with headed stud mixed shear connector’, advances in civil engineering, vol. 2019, pp. 1–16, mar. 2019. [13] a. m. ibrahim, h. m. mubarak, and a. i. said, ‘experimental study of push-out test of circular steel tube with various types of shear connectors’, in 2018 1st international scientific conference of engineering sciences 3rd scientific conference of engineering science (isces), diyala, 2018, pp. 265–270. [14] s. zheng, y. liu, y. liu, and c. zhao, ‘experimental and numerical study on shear resistance of notched perfobond shear connector’, materials, vol. 12, p. 341, jan. 2019. [15] a. modz, ‘eurocode 4: design of composite steel and concrete structures —part 1-1: general rules and rules for buildings’. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 improvingstartingcharacteristics of squirrelcage motor by using v/f control method assist. lecturer hashmia sh. dakheel assist. lecturer zainab b. abdulla university of technology university of technology hash_sh76@yahoo.co btbt_n@yahoo.com received 3 march 2015 accepted 21 january 2016 abstract: this paper presents one of the most successful method controllers of 3-phase squirrel-cage im motor which is employing v/f method with application of pulse width modulation (pwm), this dynamic model is implemented using mat lab simulation program. the improved techniques of suggested model presents high performance of improving the starting characteristics (starting current , starting torque) of the double comparison with single-cage im using pwm techniques at constant v/f control. simulation results refers to the characteristics of double-cage better than single cage and shows that the satisfy performance and good response of this model. keywords:induction motor im, single, double cage, v/f control and pwm technique. الخالصة:يقدم هذا المقال واحدة من اهم طرق السيطرة الناجحة للمحرك ثالثي االطوار ذات القفص السنجابي والذي يعمل بطريقة v/f مع تطبيقات لمضمن عرض الحزمة ((pwm هذا النموذج الديناميكي يعمل باستخدام برنامج المحاكاةmat lab . خصائص البدء )تيار البدء، عزم البدء( للمحرك ثنائي القفص مقارنة حسينعالي لتللنموذج المقترح تقدم االداء ال محسنةالتقنيات ال نتائج المحاكاة تشير الى .ثابتة v/f عند مسيطر باستخدام تقنية مضمن عرض الحزمة االطوار ثالثي المحرك احادي القفص مع حسن واالستجابة الجيدة لهذا النموذج.ان الخصائص لثنائي القفص هي افضل بكثير من احادي القفص وتبين االداء الم -:troduction in-1 the construction of threephase induction motors haven’t any mechanical commutations therefore these types of the motors are use in most of industrial application. [5], [6], [2], [9]. the induction motor has large speed range, high robustness and efficiency, low manufacturing cost. [6],[10].the cage-type machine of induction drives have applications in the industry that include:textile mills , papers, fans, pumps , air-conditioners, heat pumps , rolling mills and wind generation systems, vehicles, home applications , machines tools robotics .the range power of these machines cover fractional and horse-power to megawatts. in this time there is most application in the process control because the energy saving aspect to variablefrequency drives. [2].all these applications have drastic move away from analogue motor control to precision digital control that use variation processors digital control of induction motor results led to more efficient operation of the motor gives lower power dissipation and longer life wide. today the various control techniques of induction motor are generating variable frequency supply that v/f is the constant ratio of voltage to al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 frequency. [6].this technique is known as v/f control principles is good understood with the introduction of solid-state inverters, the constant v/f control become widely.[1]. nowadays the advances development of power electronics technology and high speed computers with associated high speed microcontrollers a.c. drive system have been available alternative to d.c. machines for variable speed applications. the induction motors have merits over the other types of industrial motors. [2]. the important of machines control algorithm fast-switching power semiconductors devices, most precise (pulse width modulation) increases particularly interest. recently the pulse width modulations have large variety in methods that which a survey was given. the large utilization the ac machine drives application, of the dc bus voltage is extremely important leds to obtain the maximum output torque at all operating conditions. [8]. there are many limitations of variable speed drives represents longer space, low speed ,poor efficiencies so, by using the power electronics to achieve the variable speed drive into a high efficiency, smaller size and high reliability. the advance in improving of control system using frequency has been designed by combinations of pwm controller. [10].this study presents the implemented system to develope the starting characteristics of induction motor for constant v/f of the motor, the comparison is done between single and double-cage induction motor drives by using pwm techniques which improve the performance of induction motor by eliminating the current harmonics of the motor. 2-double-cage im: the field control techniques can be used to control the torque developed of induction machine from flux regulation. in induction motor for variable speed drives to obtain minimize losses; the rotor resistance should be designed as low values. in construction with a general purpose induction motor, there is honked to compromise the design of the rotor cage in order to achieve adequate starting torque. in large machines (mill drive systems), high rotor current flows in rotor, therefore the rotor cage is also design large. [4]. the construction of squirrel-cage winding includes of layers short circuited bars by end rings .the upper bars have higher resistance and smaller cross-sectional area than the lower bars [7]. the effective resistance (reff ) and leakage inductance of double-cage rotor vary with frequency because at the low rotor-frequencies corresponding to small slips, reactance can be neglected and the rotor resistance reaches that of the two layers in parallel.[3]. 3-induction motor mathematical model : at start condition the rotor resistance of squirrelcage induction motor is very large compared to rotor resistance at running (fixed and small). the rotor current has frequency equal the supply frequency, hence, the starting torque per ampers is very poor ,because at standstill the starting current flows in the rotor is very large in magnitude and very large angle behind the rotor induced e.m.f in the rotor .the starting torque represents in equation:[11] ts=k1e2i2cosφ2 (1) where: ts = starting torque, e2 = e.m.f induced in rotor per phase at standstill, i2 =rotor current at starting, φ2 = angle between rotor e.m.f and the rotor current, k1= constant figure (1) shows equivalent circuit of double-cage induction motor. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 the starting current of the squirrel cage im is (5 to 7 ) times of the the full load current and the starting torque is 1.5 times the full load torque, therefore these types of motors are not used in where applications of heavy loads [11]. 4-v/f control and improve starting characterisics of im: in a squirrel cage rotors in a squirrel cage rotors no resistance can be inserted at the starting as this done wound-rotor can be developed in many a way.[11].the various schemes all make use of the inductive effect of the slot-leakage flux on the current distribution in the rotor bars. [7]. the voltage applied to the stator is proportional the torque developed on the shaft of the motor and directly proportional to the angular velocity and the product of stator flux. this led the stator the flux produced by proportional to the ratio of v/f(applied voltage and frequency of supply). the torque can be remain constant at all speed range at ratio of voltage to frequency constant .the ratio v/f makes the most common speed control of an induction motor. the torque developed is proportional to the (voltage/frequency).the ratio must be constant although we vary the voltage and frequency ,with various speed rang the torque produce in induction motor will remain constant, figure (2) shows the torque-speed characteristics of im with v/f control .the (voltage and frequency) ratio reaches the maximum value at the base speed. [6]. the torquespeed characteristics of the v/f control reveal the following: 1-the current at starting is low. 2-the stable operating region of the motor is increased instead of simply ruing at its rated speed, the motor can be run typically from 5% of the synchronous speed up to the base speed. the torque generated by the motor can be kept constant throughout this region. 3-since almost constant rated torque is variable over the entire operating ranges the speed range of the motor becomes widely user can be set the speed as per the load requirement, thereby achieving the higher efficiency. [6]. 5-improving model of im by using inverter: the desired sinusoidal voltage can be produced by pulse width modulation at a particular frequency to the squirrel cage of im inverter is controlled, a pwm provides higher performance because more efficient and typically.[10]. figure (3) shows the block diagram of induction motor using bridge and inverter rectifier to improve the starting of im, figure (4) shows the block diagram of induction motor by using (pwm) that proposes in this study, and figure (5) shows the construction of the modeling use in this study.[12]. this study presents the model that is designed in order to compare between double-cage and single cage im by using the power electronics elements. so this model consists of 3phase full bridge rectifier which is designed using (6a10bl) power diodes, the second part of model is three full bridge inverter which is pwm, the output of pwm is filtered by ( 300µf, 900v) capacitor which is used to filter the harmonics of im and threephase induction motor is the last part of the model. 6-results simulation: simulation results were obtained at constant v/f control of induction motor drives that is fed by inverter with single and double squirrel cage by using pulse width modulation refers to: al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 1 the mechanical characteristic ( torque-speed) of the single and double-cage rotors of induction motor shows in figure (6) at constant v/f. these results indicate to a higher starting torque of double –cage than single-cage rotor, but the double-cage has a smaller maximum torque , these results can be shown in table (1) . 2-tthe doublecage rotor consists of two layers (upper and lower),the simulation results refers to higher starting torque characteristic in upper-layer comparison than lower-layer which can be shown in figure (7) and table (2). the summation of two components curves led to torquespeed characteristics. 3-the current-speed characteristics that obtained of simulation program indicates to starting and rated currents for single-cage are higher than double-cage, those results can be shown in figure (8) and table (3). 4in figure (9) and (10) shows the torquespeed curves of single and double-cage rotor respectively for several excitation frequencies of three phase induction motor operating with its air gap flux remain constant at all rated condition value for all values of slips, these curves shows that the value of the torque remains the same at given value of the slips speed for any value of speed, these results can be seen in table (4) and (5) respectively. 5-the simulation results of the torque-speed curves for single and double-cages motor respectively shown in figure (11) and (12)that use excitation voltage based on stator v/f of air gap magnetic flux constant at rated value and rotor currents gives the same pull out torque. the curve of speed of magnetic field is low has much higher value of pull out torque and this speed is properly with magnetizing voltage (em) so that stator curve will be determined by stator terminal voltage and the stator winding resistance so the stator current remains constant when terminal voltage is fixed at all slips speed, these results can be shown in table (6) and (7). 6-figure (13) and (14) shows the starting torque and current for different starting frequencies for single and double-cage motor respectively, the simulation results can be shown in table (8), (9). with a low frequency start, the rotor reactance is low , hence the induced rotor current are much closer in phase to the voltage so giving high torque with high power factor and consequently minimum starting current magnitude. -conclusion:-7 by use of double-cage rotors, squirrel-cage motors can be designed to have the good starting characteristics resulting from high rotor resistance at start and at the same time good running characteristics resulting from low rotor resistance at running. the design of double-cage rotor is necessarily somewhat of a compromise and the motor lacks the flexibility of the wound-rotor machine with external rotor resistance. the current demanded by the induction motor for a direct-on line stator fixed frequency has a magnitude of approximately six times the normal full load current. with a fixedfrequency source, this starting current can only be reduced by voltage reduction. however, using the inverter drives it is possible to start at low frequency, and then raise the frequency to accelerate the motor. -references:-8 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 [1] alfredo munoz-garcia thomas a. lipo and donald w.novotny, "a new induction motor v/f control method capable of highperformance regulation at low speeds", ieee transactions on industry applications, vol. 34, no.4, july/august 1998,pp 813-820. [2] c. saravanan, a.mohamed azarudeen and s.selvakumar, "performance of three phase induction motor using modified stator winding ", global journal of researches in engineering electrical and electronics engineering, vol.12, issue 5 version 1, april 2012. [3] c.u. ogbuka, and m.u.agu, "a modified closed loop v/f controlled induction motor drive",the pacific journal of science and technology, may 2009, vol.10, no.1, pp 52. [4] j. k. seok and s.k.s ul, "pseudorotorfluxoriented control of an induction machine for deepbar-effects compensation ", ieee transactionon industry applications, vol. 34, no. 3 may/june, 1998. [5] mohamed y. kaikaa , fatima badaa, abdelmalek khezzar, mohamed boucherma, "analytical analysis of rotor slot harmonics in the line current of squirrel cage im", journal of electrical engineering, vol. 57, no. 1,2006, 12-19. [6] m.s.aspalil, asha r 2 , p.v.hunagund 3 , "three phase induction motor drive using igbts and constant v/f method", international journal of advanced research in electrical, electronics and instrumentation engineering vol. 1, issue 5, november 2012. [7] m. y. kaikaa, f. babaa, a. khzzar and m. boucherma, "analytical analysis of rotor harmonic in the line current of squirrel cage induction motors", journal of electrical engineering, vol.57, n0.1, 2006,pp 12-19. [8] r. linga swamy and p. satish kumar, "speed control of space vector modulated inverter driven induction motor", proceedings of the international mult conference vol.ii, march, hong kong, 2008 [9] safdarfasal tk and unnikrishnanl, "a performance study of pi controller and fuzzy logic controller in v/f control of three phase im using space vector modulation ", transactions on electrical and electronics engineering (itsi-teee), vol.1, issue 2, 2013. [10] shilpa v. kailaswar, prof. r .a. keswani, "speed control of three phase induction motor by v/f method for batching motion system ", international journal of engineering research and applications (ijera), vol.3, issue 2, march-april 2013 ,pp1732-1736. [11]thanga raj, s.p.srivastava and pramod agarwal, " induction motor design with limited harmonic current using practical swarm optimization", international journal of electrical and computer engineering, 3:15 2008, pp 1000. [12] thida win, nang sabai and hnin nandar maung, "analysis of variable frequency three phase induction motor drive", world academy of science, engineering and technology, 18, 2008, pp 647-650. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 166 table (1): torque-speed characteristic table (2): torque-speed characteristic in single and double-cage im. in double-cage im table (3): current-speed characteristic table (4): torque-speed with constant in single and double-cage. air gap. table (5):torque-speed of double-cage table (6):torque-speed of single with with constant air gap. constant v/f double-cage single-cage v/f torque speed torque speed 0.13 160 0 135 0 0.13 170 200 150 200 0.13 175 400 170 400 0.13 180 600 175 600 0.13 193 800 197 800 0.13 212 1000 225 1000 0.13 220 1200 240 1200 0.13 235 1400 265 1400 0.13 212 1600 240 1600 upper-cage lower-cage torque speed torque speed 132 0 16 0 120 200 18 200 110 400 23 400 96 600 25 600 80 800 34 800 65 1000 42 1000 53 1200 53 1200 42 1400 65 1400 20 1600 92 1600 torque (n-m) speed (rev/min) f(hz) 30 450 15 65 90 30 258 1100 45 132 1700 60 current speed current speed 165 200 78 200 163 400 74 400 160 600 70 600 157 800 67 800 140 1000 65 1000 130 1200 57 1200 108 1400 54 1400 70 1600 45 1600 double-cage single cage speed (rev/min) torque (n-m) f(hz) 390 68 15 740 132 30 1160 200 45 1500 264 60 speed (rev/min) torque (n-m) f(hz) 450 545 15 700 500 30 1076 265 45 1700 124 60 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 table (7):torque-speed of double-cage table (8):starting torque and current with constant v/f . in single-cage table (9):starting torque and current in double-cage figure (1): equivalent circuit of double-cage im speed (rev/min) torque (n-m) f(hz) 1565 265 60 1100 278 45 785 285 30 380 1060 15 starting torque starting current k values 232 72 0.1 270 114 0.2 258 125 0.3 232 145 0.4 210 158 0.5 193 165 0.6 170 174 0.7 167 180 0.8 starting torque starting current k values 178 40 0.1 230 55 0.2 225 61 0.3 210 63 0.4 190 65 0.5 187 68 0.6 182 72 0.7 175 75 0.8 170 78 0.9 165 83 1 r1 x1 x2 r2/s x3 r3/s xm v1 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 figure (2):torquespeed characteristic of induction motor figure (3):block diagram of system figure (4):block diagram of im by using pwm . maximum torque vs/ωe=constant vs/ωe=constant 0 0.5 1 frequency (ωe/ ωb) rated curve torque (te/tem) =consta nt maximum torque ac –to dc converter (to any dc voltage) dc to ac converter (to any frequency) ac motor ac to dc converter im inverter (pwm) al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 161 figure (5): the construction of the model fig. (6):torquespeed characteristic fig. (7):torquespeed characteristic in single and double cage. in lower and upper cage. figure (8): currentspeed characteristic. figure (9): torquespeed of single cage with constant air gap 0 200 400 600 800 1000 1200 1400 1600 1800 0 50 100 150 200 250 300 speed (rev/min) t o rq u e ( n .m ) single-cage design double-cage design 0 200 400 600 800 1000 1200 1400 1600 1800 0 20 40 60 80 100 120 140 speed (rev/min) t o rq u e ( n .m ) lower cage upper cage 0 200 400 600 800 1000 1200 1400 1600 1800 0 20 40 60 80 100 120 140 160 180 speed (rev/min) s ta to r c u rr e n t (a m p e re s ) single-cage design double-cage design 0 50 100 150 200 250 300 350 0 200 400 600 800 1000 1200 1400 1600 1800 torque (n.m) s p e e d ( re v /m in ) torque speed curves, single cage, with constant airgap flux f = 60 hz f = 45 hz f = 30 hz f = 15 hz al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 111 figure(10):torquespeed of double figure (11):torque-speed of single cage motor with constant air gap cage motor with constant v/f figure (12):torque speed of double-cage figure(13):starting torque and current motor with constant v/f . related to frequency of single-cage motor figure (14):starting torque and current related frequency of double-cage motor 0 50 100 150 200 250 300 350 0 200 400 600 800 1000 1200 1400 1600 1800 torque (n.m) s p e e d ( re v /m in ) torque speed curves, double cage with constant airgap flux f = 60 hz f = 45 hz f = 30 hz f = 15 hz 0 200 400 600 800 1000 1200 0 200 400 600 800 1000 1200 1400 1600 1800 torque (n.m) s p e e d ( re v /m in ) torque speed curves, single cage with constant v/f f = 60 hz f = 45 hz f = 30 hz f = 15 hz 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 50 100 150 200 250 300 k values starting torque and current related to frequency for single cage motor starting torque starting current 0 200 400 600 800 1000 1200 1400 0 200 400 600 800 1000 1200 1400 1600 1800 torque (n.m) s p e e d ( re v /m in ) torque speed curves,double cage with costant v/f f = 60 hz f = 45 hz f = 30 hz f = 15 hz 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 50 100 150 200 250 k values starting torque and current related to frequencyfor double cage motor starting torque starting current al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 176 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. non-linear analysis of reactive powder concrete (rpc) deep beams with openings strengthened by cfrp asst. prof .dr .ragheed fatehi makki kufa university , civil engineering department,najaf ,iraq e mail: ragheed.almutwali@uokufa.edu.iq asst.prof.dr.ali talib jassem kufa university , civil engineering department,najaf ,iraq e mail: alit.albozwaida@uokufa.edu.iq hayder abd al-latef jassem kufa university , civil engineering department,najaf ,iraq e mail: hayderaliqabi1992@gmail.com abstract: this paper mainly uses ansys v.15 , the finite element analysis software, to make nonlinear analysis of reactive powder concrete deep beams . the models simulating the test process were established, the calculation results of ansys are compared with the experimental results. data of eight rpc deep beams tested by researchers were used for comparison with ansys models .furthermore three parametric studies were carried out by changing the size of opening , location of openings and cfrp systems configuration . the comparison shows that ansys analysis results are similar to experimental results (the maximum difference in the ultimate load was less than 7.5 %), which indicates ansys analysis software can be used to simulate the mechanical property of reactive powder concrete structures. keywords: non-linear analysis , finite element, rpc deep beams , opening , cfrp 1. introduction ansys (analysis system) is a comprehensive general-purpose finite element computer program that contains over 100,000 lines of code and more than (180) different elements. it is capable of performing static, dynamic, heat transfer, fluid flow, and electromagnetism analysis. it can be used in many engineering fields, including structures, aerospace, electronic and nuclear problems. in 1971, the earliest version of ansys program was released for the first time [1]. one of the main advantages of ansys is the integration of the three phases of finite element analysis: preprocessing, solution and postprocessing. pre-processing routines in ansys define the model, boundary conditions, and loadings. displays may be created interactively on a graphics terminal as the data are input to assist the model verification. postprocessing routines may be used to retrieve analysis results in a mailto:ragheed.almutwali@uokufa.edu.iq mailto:alit.albozwaida@uokufa.edu.iq mailto:hayderaliqabi1992@gmail.com al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 177 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. variety of ways. plots of the structure’s deformed shape and stress or strain contours can be obtained in the post processing stage. according to the aci code provisions for shear , deep beams are members with length of clear span measured face to face of supports(ℓn) not exceeding four times total depth (h) (ℓn ≤ 4h ) or region of beams with concentrated loads within a distance (a) two times the total depth measured from the support (a ≤ 2h) that is loaded on one face and supported on the opposite face [2]. the presence of the web openings in the deep beams is because many ducts and pipes are necessary to accommodate essential services like air-conditioning, water supply , sewage, telephone, computer network and electricity .the depth of ducts or piping may range from a couples of centimeter to as much as half a meter[3] . reactive powder concrete is an ultra-high-strength and high ductility composite material with advanced mechanical properties. it is produced from ordinary materials (cement, very fine aggregate "0.15-0.6"mm, low water-cement ratio) , in addition to other materials (silica fume, superplasticiser, steel fibers). the maximum particle size of materials is (0.6)mm, an optimization of the dry fine powder packing has to be managed for getting very dense matrix[4] . in the present work, a finite element analysis has been conducted using ansys v.15 for eight beams deep with and without openings ,with and without cfrp strengthening tested experimentally by researchers in 2017 . a comparison of results has been made to calibrate to material models adopted in this study. and also three parametric studies were carried out by changing the size of opening , location of openings and cfrp systems configuration. 2.geometry of tested rpc deep beams eight simply supported rpc deep beams with and without web openings having a total span (l)of 1400 mm, overall depth (h) 400mm, and width 150 mm, with shear span to overall depth ratio (a/h),1 and clear span to depth ratio (ℓn/h), 3 .seven beams had two square openings (150*150 mm) symmetrically about the center of specimens. the distance between the opening center and the beam centerline for all beams was equal to 400mm. the center of opening of all beams set at the shear span center, which is the critical load path. all beams tested under two points top loading .two ø 16 mm deformed bar were used as longitudinal tension reinforcement ,table (1) showed the properties of steel bars. table (1) properties of steel bars rpc deep beams are divided into two group ,group one represents the beams (two beams) without strengthening ,group two represents the beams (six beams) strengthening by different patterns of cfrp strips. figure (1) showed the details of rpc deep beams. nominal bar diameter (mm) bar area (mm2) yield stress (mpa) ultimate stress (mpa) elongation at ultimate stress (%) 16 201 612 727.9 6 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 178 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (1) detail and geometry of beams (all dimensions in mm) 3. mechanical properties of rpc the results of laboratory tests has been adopted for compressive strength, tensile strength and modulus of elasticity ,as shown in table (2).furthermore, the strain-stress curve in figure (2) was drawn by the data of modulus of elasticity test . group one group two al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 179 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table (2) mechanical properties of rpc compressive strength of cylinder (mpa) splitting tensile strength (mpa) modulus of rupture (mpa) modulus of elasticity (gpa) 83.44 5.35 10.38 39.2 figure (2) strain-stress curve of rpc 4. finite element modeling 4.1 elements type the elements adopted in the present study were:  solid 65 used to simulate concrete.  solid 185 used to simulate loading and supporting plates.  link180 used to represent all steel bars.  shell 41 used to represent cfrp strips . 4.2 real constant the real constant for any element required specific data to work .the table (3) shows the real constant data that used for all element except the solid 185 (plate element) ,it has no real constant. 0 10 20 30 40 50 60 70 80 90 100 0 0.001 0.002 0.003 0.004 0.005 s tr e s s strain al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 180 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table (3) elements real constant *when symmetry asb =asb/2 ** depends on the cfrp direction 4.3 material properties there was a material properties for each element ,where material model number 1 indicated to solid 65 (concrete element). the requirement of this element are linear isotropic , multi-linear isotropic and concrete parameters . the table (4) shows material properties for rpc that used in the analysis. material model number 2 indicated to longitudinal reinforcement (link 180). the requirement of this element are linear isotropic and bilinear isotropic properties, as shown in table (5). material model number 3 indicated to steel plate (solid 185) at loading and supporting points. the input data are shown in table (6). material number 4 suggests to the shell 41 element ( cfrp strips) .the cfrp is assumed to be orthotropic material , where the properties of the cfrp composites are the same in any direction perpendicular to the fibers. the modulus of elasticity was taken to be 230 gpa and the poisson's ratio was assumed to be equal to zero [6] .table (7) shows the cfrp properties entered in the present work. element type real constant value adopted solid65 (concrete) material no. 0 volume ratio orientation angle (theta) orientation angle (phi) link180 (steel bar ø16) cross-sectional area (mm2) 201* initial strain 0 shell41 (cfrp sheet) shell thickness at node i,j,k,l 0.167 element axis rotation theta ** elastic foundation stiffness 0 added area (mass/unit) 0 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 181 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table (4) material model for concrete table (5) material model for steel reinforcement table (6) material model for steel plates material properties for element solid 65 linear isotropic modulus of elasticity, mpa ex 39300 poisson's ratio prxy 0.2 multi linear isotropic points number strain stress ,mpa 1 0.000288 11.317 2 0.000582 22.635 3 0.000950 33.953 4 0.001287 45.271 5 0.001688 56.589 6 0.002217 67.906 7 0.003173 79.224 8 0.004243 83.7 concrete parameters shear transfer coefficients for an open crack shrcf-op 0.1 shear transfer coefficients for a close crack shrcf-cl 0.15 uniaxial tensile cracking stress, mpa. untensst 5.35 uniaxial crushing stress (positive), mpa. uncompst 83.44 material properties for element link 180 bilinear isotropic modulus of elasticity, mpa ex 200000 poisson's ratio prxy 0.3 bilinear isotropic yield stress, mpa yield stss 640 tangent modulus, mpa tang mod 6000 material properties for element solid 185 linear isotopic modulus of elasticity, mpa ex 200000 poisson's ratio prxy 0.3 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 182 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table (7) material model for cfrp strips 4.4 geometry in the finite element analysis, tested rpc beams experimentally, modeled by taking the benefit of the symmetry of the deep beams supports and loadings. the finite element mesh for quarter of the beam is shown in figure (3) to simulate the rpc deep beams . in this study, perfect bond between materials is assumed .discrete representation (link 180) was used to model steel reinforcement . the beam and plates were modeled as 8 node elements, while the steel bars were modeled as a straight elements, also the 4 node shell is used for modeling cfrp strips. the figure (4) shows details of elements modeling. figure (3) geometry of the numerical model material properties for element shell 41 linear orthotropic ex 230000 ey 1 ez 1 prxy 0 pryz 0 prxz 0 gxy 1 gyz 1 gxz 1 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 183 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (4) details of elements modeling 4.5 loads and boundary conditions in ansys, the applied load was represented by dividing the total distributed load on the top nodes according to the area surrounded by each node to represent the distributed load in ansys program as shown in figure (5). the supports were approximately as similar as in the experimental work. figure (5) details of applied load and boundary conditions al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 184 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 5. results of finite element analysis the results of finite element analysis using ansys program were compared with the experimental results for all tested beams. the numerical failure was similar to the failure mode of each beam that occurred in experimental work. ansys results including ultimate load, load-deflection response and crack patterns where a close to the experimental results. 5.1 numerical ultimate load the comparison between the ultimate load from the experimental results and numerical models from finite element analysis of the analyzed beams are listed in table (8) . the difference between the experimental ultimate load and that obtained by finite element analysis is not more than (7.5) %. table (8) comparison between the experimental and numerical ultimate loads beam ultimate load(kn) [[ 𝑝𝑢)𝐴𝑁𝑆𝑌𝑆 − 𝑝𝑢)𝐸𝑋𝑃.] /𝑝𝑢)𝐸𝑋𝑃.] % 𝑝𝑢)𝐸𝑋𝑃. kn 𝑝𝑢)𝐴𝑁𝑆𝑌𝑆 kn cbs 594 622 4.71 cbo 177 182 2.83 bse1 197 201 2.03 bse2 240 258 7.5 bse3 249 254 2.01 bse4 315 329 4.44 bse5 220 229 4.09 bse6 268 274 2.24 5.2 load-deflection curves the load-deflection curve for each beam obtained from the finite element analysis together with the experimental curves are presented and compared in figures from (6) to (13). in general, all these figures show a good agreement between the experimental and f.e.a curves. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 185 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (6) experimental and numerical load-deflection curves for beam cbs 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 0 1 2 3 4 5 6 7 8 lo a d ( k n ) mid span deflection(mm) numerical experimental 0 50 100 150 200 250 0 1 2 3 lo a d ( k n ) mid span deflection(mm) numerical experimental al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 186 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (7) experimental and numerical load-deflection curves for beam cbo figure (8) experimental and numerical load-deflection curves for beam bse1 0 50 100 150 200 250 0 1 2 3 lo a d ( k n ) mid span deflection(mm) experimental numerical al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 187 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (9) experimental and numerical load-deflection curves for beam bse2 figure (10) experimental and numerical load-deflection curves for beam bse3 0 50 100 150 200 250 300 0 1 2 3 4 lo a d ( k n ) mid span deflection(mm) experimental numerical 0 50 100 150 200 250 300 0 1 2 3 4 lo a d ( k n ) mid span deflection(mm) experimental numerical al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 188 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (11) experimental and numerical load-deflection curves for beam bse4 figure (12) experimental and numerical load-deflection curves for beam bse5 0 50 100 150 200 250 300 350 0 1 2 3 4 5 lo a d ( k n ) mid span deflection(mm) experimental numerical 0 50 100 150 200 250 0 1 2 3 4 lo a d ( k n ) mid span deflection(mm) experimental numerical al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 189 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (13) experimental and numerical load-deflection curves for beam bse6 5.3 crack patterns the numerical-model painted the cracks at all stages of loading. cracking-patterns in the beams was obtained using the crack/crushing plot option in ansys v.15. according to ansys program, the first crack which represented slight crack is symbolized by a red circle outline at an integration point, the second crack which represents moderate crack is symbolized by a green circle outline, and the third crack which represents failure crack is symbolized by a blue circle outline. the results showed a good agreement in crack patterns and failure mode between numerical and experimental tested beams as shown in figure(14) and figure(15) . 0 50 100 150 200 250 300 0 1 2 3 4 5 lo a d ( k n ) mid span deflection(mm) experimental numerical al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 190 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (14) crack pattern for beam cbo at failure load figure (15) crack pattern for beam sbe1 at failure load 6. numerical parametric study in the present work, an important factors were studied by using numerical models to investigate their influence on the behavior rpc deep beam with openings .the considered parameters are the size of opening , location of openings and cfrp systems configuration . al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 191 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 6.1 openings location the first assumption in this parameter was change the horizontally location of the opening with respect to the shear span . five models with different distances from the support center to the opening center as 175 ,225 ,250 , 275 and 300 mm were used in this assumption as shown figure (16). the results showed that when the location of opening was changed horizontally from the critical location at the center of shear span , the strength of beam was increased significantly , whenever was opening located further away from critical location toward middle of span . as shown in figure (17) . the second assumption in this parameter was change the vertically location of the opening with respect to the shear span . two models with different distances from the bottom face of beam to the opening center as 125 and 275 mm were used in this assumption as shown in figure(18). the results showed that when the location of the opening changed vertically from the critical location at the center of the shear span ,the strength of beam was increased significantly as shown in figure (19) . the reason of increase the strength in the two assumptions due to the opening moving from the critical location at shear span that deals with the previous study. figure (16) horizontal changes in locations of the opening al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 192 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (17) load-deflection curves of first assumption figure (18) vertical changes in locations of the opening 0 50 100 150 200 250 300 350 400 0 1 2 3 4 lo a d ( k n ) mid span deflection(mm) 300 275 250 225 175 200 (cbo) al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 193 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (19) load-deflection curves of second assumption 6.2 openings size to explain the effect of opening size on the behavior of rpc deep beam with openings ,four sizes of opening were provided (50x50 , 100x100 , 200x200 and 250x250 mm ) at the center of shear span .figure (20) shows the load deflection curves of several cases of deep beams which have different opening sizes compared with numerical beams ( cbs and cbo). the results showed that the ultimate load was decreased with increasing the opening size . the strength of beam was decreased significantly compared with solid beam , table (9) shows the reduction in strength due to existence of different opening sizes compared with numerical solid beam .the explain of decreasing the strength with increasing the size of opening due to the diagonal cracks at corner along a line joining the support and load points cracks crossing minimum distances to occur the failure. 0 50 100 150 200 250 300 0 1 2 3 lo a d ( k n ) mid span deflection(mm) 125 275 200 (cbo) 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 0 1 2 3 4 5 6 7 8 lo a d ( k n ) mid span deflection(mm) cbs 50x50 100x100 150x150 (cbo) 200x200 250x250 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 194 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (20) load-deflection curves of several cases of deep beams with different opening sizes table(9) the strength reduction in deep beams due to existence of different opening sizes model ultimate strength (kn) strength reduction respect to solid beam % beam without opening (solid) 623 _______ beam with opening (50x50) 524 15.89 beam with opening (100x100) 339 45.59 beam with opening (150x150) 182 70.79 beam with opening (200x200) 97 84.43 beam with opening (250x250) 42 93.26 6.3 cfrp systems configuration to study the effect of these three system on the strengthening process of rpc deep beam with openings ,three model (full warp , u-wrap and two sides wraps) were used by taking cfrp strips patterns of bse2 as a case study .the models were have the same system shape in front view as shown in figure (21) . according to results of ansys as shown in figure (22) , the ultimate load and the mid span deflection of three systems were very close and the difference was not noticeable . the explain of that behavior is the failure of deep beam with opening (which located at the load path) occurs at the corners of opening , because that was no difference among the three configuration systems. figure (21) front and side view of full warp, u-wrap and two sides wraps models al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 195 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure(22) load –deflection curves of full warp, u-wrap and two sides warps models 7. conclusions 1the comparison between the f.e.a and the experimental results asserted the validity of the numerical analysis and the methodology developed. the maximum difference in the ultimate load was less than 7.5 %. 2-from the comparison between the numerical models (full warp),(u-warp) and (two sides warps), it can be observed that there is no significant effect for the vertical anchorage warp if it used for the deep beam with openings. 3the presence of opening in deep beam (at critical location of shear span) decrease the strength and increase the deflection , and that effect become higher with increasing the size of opening .when the opening size were (50x50 ,100x100 ,150x150 ,200x200 and 250x250) mm the ultimate load decreased about (15.89 ,45.59 , 70.79 , 84.43 , 93.26) % respectively. 4when the location of opening was changed horizontally from the critical location at the center of shear span , the strength of beam was increased significantly about (12 80 )% . 5-when the location of the opening changed vertically from the critical location at the center of the shear span ,the strength of beam was increased significantly about (41 57)% . 6the crack patterns at the final load from the finite element model had a good match with the noticed failure of the experimental results. 0 50 100 150 200 250 300 0 1 2 3 4 5 lo a d ( k n ) mid span deflection(mm) full warp u warp two sides warps al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 196 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. refrences 1-al-shimmari i,kh. , hamad n.t. and waryosh w.a. investigation of the behavior for reinforced concrete beam using non-linear three-dimensional finite elements model .engineering college, university of almustansiriya/baghdad ,eng. & tech. journal, 29(10) ,2011, pp.1870-1885 . 2-aci committee .building code requirements for structural concrete (aci 318-14) and commentary(aci 318r-14), american concrete institute, farmington hills, mi, 519 pp. 3-mansur ma, tan kh. concrete beams with openings: analysis and design. crc press; 1999 jan 29. 4maroliya mk. state of art-on development of reactive powder concrete. international journal of innovative research and development. 2012 oct 1;1(8):493-503 5-ansys help v 15.0 . a finite element computer software theory and user manual for nonlinear structural analysis . 6-al-habbobi ,a.m .the use of cfrp for shear strengthening of reactive powder concrete beams. phd thesis, albasrah university , 2014, pp.204. 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 دراسة االمكانات التنموية الستثمار المياه الجوفية في محافظة النجف االشرف زينب ديكان عباس الكالبي .م.م قسم التخطيط البيئي –كلية التخطيط العمراني/ جامعة الكوفة مائيةماجستير هندسة موارد 5102كانون الثاني 10ُقبل في 5102تشرين االول 22أستلم الخالصة وفي العراق تعد المياه الجوفية من الموارد المائية المهمة في المناطق الصحراوية والشبه صحراوية في العالم واألنهار والبحيرات والمياه الجوفيه هي المياه التي تسربت خالل طبقات األرض من األمطار بشكل خاص. مختلفه عن سطح األرض تتغير من هذه المياه تتواجد في باطن األرض على أعماق وبمرور السنين العذبه موقع ألخر وذلك حسب التكوين الجيولوجي للتربه. وأهميه المياه الجوفيه تزداد بصفه مستمره نظرا لزياده الطلب اعيه والشرب.الصن, الزراعيه ,على المياه لجميع األغراض -:لكي تحقق المسح الشامل لمنطقة الدراسة ينمحور بحثال تناول : تم الحصول على بيانات تخص المياه الجوفية من وزارة االعمار واالسكان من خالل فحوصات تحريات االول تم التعرف من خاللها على اعماق المياه الجوفية )محافظة النجف االشرف(التربة التي اجريت لمنطقة الدراسة وطبيعة طبقاتها وتم االستعانة ببرنامج نظم المعلومات الجغرافية كاحدى الوسائل الظهار مناسيب المياه -وكانت :الجوفية الموقع ( الى 1) المواقع من رقم ) خمس مناطق مختلفة في محافظة النجف االشرف تمثلت في (1 (متر.11-1.1)تراوحت اعماق المياه الجوفية فيها (0214( لعام 5رقم ) الموقع )فيتمثلت ( اعاله 1تختلف في مواقعها عن )عشر مناطق مختلفة في محافظة النجف االشرف (0 .متر(1.9-12.5) تراوحت اعماق المياه الجوفية فيها (0211لعام 12الموقع رقم الى 1 من 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 وهي محافظة النجف االشرف علىموزعة مختلفة على مناطق كيميائية فيزيائيةو دراسةاجراء تم : نياثال تراوحت اعماقها من جف الفضائيةنوهي موضحة في مرئية ال (0,1) تختلف عن المناطق في المحور االول حيث عمدت وزارة البيئة بااليعاز الى مديرية بيئة محافظة النجف االشرف باجراء 0214لعام متر ( 02-02) وقد تم طرحهافي البحث لغرض معرفة امكانية استثمارهامن دورية لهذه االبار للوقوف على نوعها. فحوصات التوصيلية ,( phاالس الهيدروجيني ) ,قياس درجة الحرارة )الماء( ) بفحوصات تمثلت .خالل فحوصات الوزارة يونات ,اال tss العالقة الكلية االمالح, tdsاالمالح الذائبة الكلية , turbidityالعكورة ,( ecالكهربائية ) so4-,cl-, hco3-,-co3, no3-) po4 األيونات السالبة( +k, mg2+,ca2+,naالموجبة) )صالحية المياه للشرب وفقا لمعيار منظمة الصحة جداولوتمت مقارنة نتائج هذه الفحوصات مع (-, (( isecoاالسالمية للتربية والثقافة والعلوم )صالحية المياه للري وفقا لمعيار المنظمة ) ,(w. h . oالعالمية )محددات المياه الصناعية(. و تم التوصل من خالل البحث الى ان المياه الجوفية في محافظة النجف االشرف موجودة باعماق ومناسيب المختلفةونوعيات ممكن االستفادة منها كمصدر بديل ولالغراض المختلفة منها الشرب , الري , والصناعات .خاصة وان هناك بعض االبار تحتوي على نسبة من الملوحة يمكن معالجتها بالطرق الحديثة قبل استخدامها studying the development potentials to invest groundwater in najaf ashraf state zainab degan abbasse al-kelabbee a.leacture kufa university physical planning college environmental department abstract the under ground water is considered one of the most important resources of water in desert and semi desert regions in the world and spatially in iraq. the underground water is the water that escaped through the surface layers from rain water , rivers , and sweet laks , by time this water exists in the earth care with depth that differs from one place to another due to the geological nature of soil . the importance of underground increases conyounsoully with the requsel for water to an agriculture , undustrial , and drinking needs. the research investigated tow points in order to achieve a comprehensive survey of the study area: the first : the undergroundwater data was taken from ministry of construction and housing through soil invistegations tests that was conducted for the study region which through it the depth of underground identified and also its layers type and characteristces and we used giographical information system program as a tool to show the levels of undergroundwater 1-the study area included five different regions in najaf state they are locations from 1 to no. 5 for year 2014 the depths of ground water on it ranged from (1.3-11)m. 2-ten different regions in najaf state that differ from the areas in (1) above they are locations from 1 to no.10 for year 2013 the depths of ground water on it ranged from (1.9-12.5)m. 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 the second :a physical and chemical study was conducted on different areas spread over the province of najaf that differ from the areas in the first section (1,2) and they are shown in the visible najaf satellite, the depths ranged from (20-90 m) for 2014 were obtained from the environment directorate of najaf, where the ministry instructed the environment directorate to conduct periodic tests for these wells to determine their types. and they were discussed in the research in order to know the possibility of investing them through the ministry experiments. they were represented by the tests (measuring temperature (water), potential hydrogenii (ph), electrical conductivity (ec),turbidity, total dissoluble salts tds , total suspended salts tss, cations (positive ions) (k, mg2 +, ca2 +, na +) negative ions (so4-, cl-, hco3 -, co3, no3-, po4-,), and results of these tests were compared to the tables of (water drink validity) according to the who’s standards (world health organization), (water validity for irrigation, according to the standard of the islamic education, culture and science organization (iseco) and (industrial water criteria)). it was conducted through the research that the groundwater in the province of najaf exists with depths, levels and types, that can be utilized as an alternative resource and for different purposes, including drinking, irrigation, and various industries with some treatments that the water needs in several wells, in order to be valid for the required purposes specially treating it from salts. المياه الجوفية ، تنمية المياه الجوفية ، اعماق المياه الجوفية ، خصائصدراسة االمكانات ، : كلمات مفتاحية محافظة النجف االشرف المقدمة: اإلنسان على احتياجاته المائية من مصدرين أساسيين وهما مصادر المياه السطحية وتشمل مياه األنهار يحصل مكون ما يسمى بالمياه والبحيرات ومجاري الوديان ومصادر المياه األرضية وتشمل اآلبار والينابيع والكهوف بر أزمنة مختلفة تكون حديثة أو الجوفية وهي عبارة عن مياه موجودة في مسام الصخور الرسوبية تكونت ع قديمة جدا لماليين السنين. فقد نشأ اعتقاد بأن المياه السطحية تشكل المورد الرئيسي إلحتياجات العالم من المياه % من المياه العذبة المتاحة على كوكب األرض توجد في األنهار والبحيرات أما 1ولكن في الواقع فإن أقل من كما ( كيلومتر مكعب.122,222% فإنه يوجد في باطن األرض وُيقدر بحوالي )09مثل الجزء األكبر والذي ي وتعد دراسة المياه الجوفية من الدراسات المهمة وذلك من اجل الحصول على مصادر للمياه ممكن أن تستخدم .ريةألغراض التنمية في المجال االروائي والزراعي والمجاالت العمرانية والصناعية ولألغراض البش الى تحليل بعض مياه ]1[البحث عمد الباحثلقد اجريت بحوث عديدة في مجال استثمار المياه الجوفية حيث الى [13]عمد و االبار في منطقة الخفاجيةفي االنبار من اجل معرفة مدى مالئمتها الغراض الري والشرب في دراسة هيدروجيوكيمياوية [5] حثكما وب, في منطقة مشروع المسيب استخدام المياه الجوفية الغراض الري للمياه الجوفيةفي الجزيرة القريبة من سامراء تم من خاللها التوصل الى امكانية استخدام هذه المياه الغراض كربالء ان منطقة –في دراسة هيدروجيولوجية للمنطقة المحصورة بين نجف ]6[ووضح .الري والنشاط البشري 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 وعمل . وجود االمالح في مياهها الجوفية بنسبة عالية لكنها تستخدم الغراض الزراعة الدبدبة على الرغم من على اجراء دراسة فيزيوكيمياوية لمعرفة جودة المياه واجريت الدراسة على آبار مدينة .[15]الباحثان وايضا اجرى . )غانا(الهدف منها مساعدة واضعي القرار من اجل وضع معايير خاصة لمنع تلوث المياه ( بئر 92دراسة في مدينة تبريز في ايران حيث تم تقييم المياه الجوفية من خالل اخذ عينات )[14] الباحثين ومن خالل اجراء الفحوصات الكيميائية لهذه المياه.في مدينة تبريز ومناطقها الريفية بالنقاط التالية:تتمثل مشكلة البحث ومن الجدير بالذكر ان طبيعة طبقات المياه الجوفية في محافظة النجف االشرف ؟ما هي -1 ماهي مناسيب واعماق المياه الجوفية في محافظة النجف االشرف ؟ -0 ماهي نوعية المياه الجوفية في محافظة النجف االشرف؟ -1 اما فر ضية البحث فهي لفةان المياه الجوفية في محافظة النجف االشرف هي ذات طبقات مختلفة بخصائص مخت-1 ان المياه الجوفية بمحافظة النجف االشرف ذات مناسيب واعماق معينة تختلف حسب طبوغرافية منطقة -0 الدراسة. ان نوعية المياه الجوفية تختلف من مكان الخر وحسب الخصائص الكيمياوية لها.-1 كاالتي: ياهمية البحث فه وان فال بد من اجراء كافة الدراسات ذات العالقة بالبحث عن ان العالم العربي مقبل على شح في الموارد المائية مصادر بديلة كالمياه الجوفية . نهج البحث بالخطوات االتية:مويوضح سوف يعتمد البحث من خالل المنهج االستقرائي الستعراض واقع حال المياه الجوفية في محافظة النجف عالمية الخاصة بصالحية المياه الجوفية للشرب والري االشرف وبعد ذلك مقارنة ما هو منتج مع المواصفات ال والصناعة وتشخيص مدى مالئمة المياه الجوفية لهذه االغراض وبالتالي الخاصة بالنتائج والتوصيات الخاصة بالبحث. منطقة الدراسة باحيائه الشمالية والجنوبية (0-1)بالنسبة للمحور االول تمثلت منطقة الدراسة في محافظة النجف االشرف ( 12-1ومن ) 0214(بالنسبة لبيانات 5-1)الموقع والوسطى وحسب المناطق التي تناولها الباحث في بحثه الشكل في ( كما gis) وكما تم توضيحه من خالل برنامج نظم المعلومات الجغرافية 0211بالنسبة لبيانات 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 وكما لها المواقع التي تم اخذ فحوصات المياه الجوفية الشكلتمثلت النقاط الموجودة في الحقا. (0) رقم يات التربة ر تح فحوصات عن طريقانات يموضحة مواقعها على مرئية النجف الفضائية وتم الحصول على الب وهي الفحوصات التي يتم من خاللها معرفة مناسيب وطبيعة المياه من قبل مختبرات وزارة االعمار واالسكان فان نيبالنسبة للمحور الثا اما .الجوفية قبل اقامة االسس التابعة للمنشآت المراد اقامتها على الموقع المعني وهي تختلف عن المناطق موزعة على مناطق متفرقة من محافظةالنجف االشرف المفحوصة كيمياويا االبار ( , بحر النجف آبار 1تمثلت بمناطق) بنات الحسن بئر رقم) (5الشكل رقم ) فيوكما مالحظ المحور االولب (, حي 11( , حي الحرفيين بئر رقم )12, 0,7,9,9(, البراكيةآبار رقم )5,4( , قرية مظلوم آبار رقم )1,0رقم) ( , حي النفط بئر 17( , حي الغدير بئر رقم )19,19,15,14,11(, حي الحنانةبئر رقم)10ميسان بئر رقم ) .(00,01.02كربالء بئر رقم )-( , طريق نجف10رقم ) العوامل التي تؤثر على المياه الجوفية اوال :السطح 0كم 07702تقع جنوب غرب العراق تصل مساحتها -محافظة النجف احدى محافظات الفرات األوسط 0كم 417119% من مساحة العراق البالغة 6.6وتشكل ويتألف سطح المنطقة من قسمين : % من مسااحة المحافظة5كم ويسااوي 1122القسم الشرقي )السهل الرسوبي /تصل مساحتها الى -1 0كم 10222% من مساحة السهل الرسوبي البالغة 1.4وحوالي %من مساحة المحافظة 05وتشكل 0)كم 09504القسم الغربي /الهضبة الغربية /تصل مساحتها ( -1 د في منطقة الدراسة متمثلة بالهضبة الغربية .من هذا نجد أن المساحة العظمى تتجس الخصائص المناخية ثانيا: نستعرض ابرز الخصائص (0رقم ) الجدولفي يؤثر المناخ تاثير مباشر على احتياج المزروعات للمياه (ملم , اذ تتباين 011.0)في منطقة الدراسة بلغ لكمية االمطاريتضح من الجدول ان المجموع المناخية ، في حين تنقطع ( ملم51.2)معدالت سقوط االمطار شهريا لتصل في اقصاها في شهر كانون الثاني وتبلغ ايلول( من ذلك تكون االمطار قليلة مما التساعد على تلبية االحتياجات -آب -تموز –كليا في شهر )حزيران فان المعدل السنوي العام لها يبلغ للرطوبة النسبية المائية المطلوبة لسد حاجة المزروعات , اما بالنسبة وذلك لكثرة الغيوم (%21)ويتباين هذا المعدل شهريا ليصل الى اقصاه في شهر كانون الثاني ويبلغ (21.5) 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 وسقوط االمطار خالل هذا الشهر ثم تاخذ هذه المعدالت باالنخفاض لتصل ادناها في شهر تموز لتصل جة الحرارة خالل هذا الشهر مما يؤدي الى فقدان رطوبة التربة وزيادة الجفاف وبالتالي وذلك الرتفاع در (52%) فان المعدل السنوي العام لسرعة الرياح يبلغ للرياح زيادة نسبة الضائعات من السطوح المائية والتربة , بالنسبة رياح في االشهر الحارة , اذ تنشط حركة الرياح في فصل الصيف لتسجل اعلى معدالت لسرع ال (م/ثا5.5) م/ثا على التوالي في حين تقل سرعة الرياح عن هذه المعدالت في االشهر (1.0-1))حزيران, تموز( بمعدالت على التوالي حيث ان الرياح تؤدي (0.2-0.2)الباردة لتصل ادناها في شهر )تشرين الثاني وكانون االول الى يتضح من التبخروالتربة وبالتالي زيادة حجم الضائعات المائية , الى زيادة نسبة التبخر من السطوح المائية وتتباين معدالت التبخر لتبلغ اقصاها في (ملم1221.3)الجدول ان مجموع كمية التبخر السنوي مرتفعة وتبلغ ويعزى ذلك الى ارتفاع درجات الحرارة وانخفاض الرطوبة النسبية في الجو وقلة او ( ملم229.2)شهر تموز ويعزى ذلك الى انخفاض درجات (ملم 25.2)انعدام الغيوم في حين تبلغ ادناها في شهر كانون الثاني بمعدل الحرارة وارتفاع معدالت الرطوبة النسبية في الجو وزيادة الغيوم ومما يجدر الذكر ان ارتفاع نسبة التبخر تؤدي االشعاع الشمسي, التي تحتاجها المزروعات , الى زيادة حجم الضائعات المائية وبالتالي زيادة عدد الريات وانه العامل المهم في تحديد مقدار الحرارة , يمثل االشعاع الشمسي المصدر الرئيسي للطاقة على سطح االرض المتوفرة في المنطقة والتي يتم من خاللها تحديد معدالت درجات الحرارة التي تحدد قيم الضغط الجوي في ويتضح من الجدول ان ع الفلكي في كمية االشعاع الشمسي وزاوية سقوط االشعاع الشمسييؤثر الموق المنطقة وهذا المعدل يتباين شهريا اذ يبلغ 5(سعرة/سم252.29)المعدل السنوي العام لكمية االشعاع الشمسي بلغ ية االشعاع بسبب صفاء السماء وقلة الرطوبةالنسبية وكبر زاو 5( سعرة/سم220.9)اقصاه في شهر حزيران تأخذ كمية االشعاع الشمسيبالتناقص تماشيا مع تناقص زاوية االشعاع الشمسي وطول مدة السطوع الشمسي 5( سعلرة/سم523.12)وطول النهار اذ تصل في ادناه في شهر كانون االول اذ تبلغ كمية االشعاع الشمسي ثرة الغيوم وارتفاع معدالت الرطوبة النسبية وذلك الن زاوية االشعاع الشمسي تصل الى اقل ما يمكن وذلك لك وسقوط االشعة الشمسية بصورة مائلة يتضح من ذلك ان منطقة الدراسة تستلم كمية كبيرة من االشعاع الشمسي لساعات طويلة من النهار بسبب موقعها الفلكي وهذا يؤثر في ارتفاع درجات الحرارة ونسب التبخر والنتح وزيادة مائية من سطوح االنهار والجداول وترب الحقول الزراعية االمر الذي يتطلب معه زيادة حجم الضائعات ال يتضح من الجدول ان , درجات الحرارة , كميات مياه الري وبالتالي استنزاف الموارد المائية في منطقة الدراسة باالرتفاع مع شهر آذار بمعدل يتباين هذا المعدل شهريا اذ بدأ º(م52.0يبلغ ) المعدل السنوي لدرجات الحرارة ثم تأخذ باالنخفاض ليصل في ادناه في شهر كانون º( م12.2)حتى يصل اقصاه في شهر تموز º( م02.9) يتضح من الجدول ان ارتفاع درجات الحرارة وخاصة خالل اشهر الصيف الحار يؤدي الى º( م01.3)الثاني ارتفاع نسبة التبخلر من السطوح المائية من جهة وارتفاع النتح من سطوح االوراق النباتية من جهة اخلرى االمر الذي يؤدي الى زيادة حجم الضائعات المائية واستنزاف الموارد الموارد المائية السطحية 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 32 -ثالثا:الخصائص الطبيعية للمياه الجوفية: اصل المياه الجوفية -0 المياه الجوفية في منطقة الدراسة من مياه جوفية ذات اصل بحري متمثلة بخزان الفرات الى يتباين اصل مياه جوفية ذات اصل جوي متمثلة بخزان الدمام وهي اهم خزانات منطقة الدراسة كون التكوينات سة.منطقة الدرا منتنتشر ضمن مساحات واسعة في هذا االقليم الجيولوجية التي تحوي هذه الخزانات wt)مستوى سطح الماء الجوفي )عمق او منسوب , -5 ( و هو يعرف بمستوى سطح الماء water tableهو عمق سطح الماء الجوفي أسفل سطح األرض ) االستاتيكي ) أي الساكن ( الذي يكون في األحوال العاديه بدون ضخ مياه و هو يكون سطح الماء الجوفي المصطلح ال يستخدم أال لخزان المياه الجوفي حر السطح . تتباين واحد في كل من البئر و الخزان وهذا اعماق المياه الجوفية في منطقة الدراسة مع ارتفاع السطح في منطقة الدراسة من مكان آلخر اذ تكون ذات عمق كبير في المناطق االكثر ارتفاعا وبشكل عام يزداد عمق هذه المياه كلما اتجهنا نحو الغرب (1,0فبالنسبة للمحور االول ) .وذلك لزيادة االرتفاع بهذا االتجاه م022م الى 52ربي من والشمال الغ المناطق التي تم التعرف على اعماق المياه الجوفية فيها من خالل فحوصات ( 5الشكل رقم ) يوضح تمثلت من تحريات التربة للمشاريع المقامة في تلك المنطقة وهي موزعةبمواقع حسب تواجدها على المرئية 0211( وباللون االزرق للبيانات لعام 12-1ومن ) 0214( وباللون االحمر للبيانات الخاصة لعام 1-5) هذه يوضح اعماق ومناسيب (5للجدول رقم )كما وتم ذكر اسماء المناطق لهذه المواقع ايضا. بالنسبة لبيانات 11m-1.3m))ومن 0211لبيانات m 1.9-12.5) المناطق حيث تراوحت االعماق من ) طريق ,منطقة العباسية , لى فحوصات في منطقة الحيدرية ع مرئيةويحتوي البحث من خالل ال 0214 بالنسبة .لمنطقة الدراسيةالسكنيةلحدود البلدية للمناطق نجف كربالء وفي البراكيةوهي تقريبا خارج ا . ]3 [( متر02-02فقد تراوحت االعماق للمياه الجوفية ) نيللمحور الثا 1] 5 [حركة المياه الجوفية في منطقة الدراسة ثالثا: تقسم حركة المياه الجوفية الى ثالث مناطق رئيسية وهي مناطق السهل الفيضي ومنطقة جزيرة النجف والبادية .  تكون حركة المياه الجوفية عمودية على اتجاه االنهار ذهابا وايابا حسب مناطق السهل الفيضي : ارتفاع وانخفاض مناسيب مياه االنهار  تكون حركة المياه الجوفية باالتجاه الشرقي واالتجاه الجنوبي الشمالية منطقة جزيرة النجف : الشرقي حيث المنطقة االكثر انخفاضا في الهضبة 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 23  حركة المياه الجوفية باالتجاه الشمالي الشرقي حيث المنطقة االكثر : تكون مناطق البادية انخفاضا وهي مناطق بحر النجف 1] 5 [رابعا: توزيع وكثافة االبار في منطقة الدراسة -تتمركز االبار في المناطق التالية: ( بئر منتج تتمركز في المناطق القريبة 1722تقريبا ) االبار فيهاجزيرة النجف الشمالية وتتراوح اعداد -1 كربالء –من طريق نجف البادية تكثر االبار في بحر النجف في جميع مناطقه حيث النوعية الجيدة والكمية العالية للمياه الجوفية -0 حيث تعتبر المنطقة مناطق تكسرات وخزن اضافة الى مرور فالق ابو الجير الذي يشكل خزان جوفي عمالق مع وجود تكوينيين عمالقيين هما تكوين الفرات وتكوين الدمام . ومناطق بحر النجف هي ( بئر كذلك مناطق الحياضة 522مشجعة على االستثمار ويبلغ عدد االبار التقريبي الى حدود ) ر والرحبة وغيرها اما مناطق جنوب غرب بحر النجف وصوال الى الحدود العراقية السعودية فهي تعتب مناطق اعادة تغذية ومناطق ال تتجمع فيها المياه الجوفية لذا تقل فيها االبار وتكون االبار ذات انتاجية .الجداولقليلة مع اعماق كبيرة ووجود نوعية رديئة للمياه حيث يحتوي على امالح عالية ومواد كبريتية الفحوصات الكيمياوية ( 00من اجل معرفة االمكانات المتاحة الستثمار المياه الجوفية في محافظة النجف االشرف تم الحصول على ) لبيانات غير منشورة ولعام االشرف دائرة بيئة محافظة النجفمن قبل نموذج من االبار مفحوصة كيمياويا الجدول وتم ترقيمها في (5رقم ) في الشكلوكما موضح مواقعها على مرئية النجف الفضائية حصرا 0214 وكما مالحظ من المرئية فان االبار موزعة على مناطق متفرقة من . حسب وجودها في المرئية ( 1رقم ) , (1بئر رقم) تمثلت بمناطق) بنات الحسن وهي تختلف عن مناطق المحور االول محافظةالنجف االشرف , حي (12, 0,7,9,9آبار رقم ), البراكية(5,4آبار رقم ) , قرية مظلوم (1,0آبار رقم) بحر النجفقرب بئر , حي الغدير (19,19,15,14,11بئر رقم), حي الحنانة(10حي ميسان بئر رقم ) (,11بئر رقم ) الحرفيين وتراوحت اعماق هذه االبار (00,01.02بئر رقم ) كربالء-, طريق نجف (10بئر رقم ) , حي النفط (17رقم ) (متر02-02من ) ]2 [ القياسات الفيزيائية والتحاليل الكيميائية القياسات الفيزيائية اوال : 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 23 (ph)تشمل التحاليل الفيزيائية على قياس درجة الحرارة )الماء( واللون والطعمم والرائحمة واالس الهيمدروجيني tssواالمممالح العالقممة الكليممة tdsواالمممالح الذائبممة الكليممة turbidityالعكممورة و (ec)والتوصمميلية الكهربائيممة وتممم قيممماس بعمممض همممذه الفحوصمممات فممي دائمممرة بيئمممة محافظمممة النجمممف لمجموعممة ممممن االبمممار الموزعمممة علمممى منطقمممة الدراسة. التحاليل الكيميائية ثانيا : تعتبممر الدراسممات الكيمياويممة للميمماه الجوفيممة مهمممة فممي تحديممد صممالحية الميمماه لألسممتعماالت المتعممددة االغممراض وتلقي الضوء على تأريخ الصخور الخازنة وسرعة وحركة المياه، وان عملية دراسة التحاليمل الكيميائيمة تفيمدنا فمي وذلك كونها تستطيع تحديد صمالحية الميماه لألسمتخدامات المتنوعمة وتعتبر مهمة التحري عن التجمعات المعدنية ية للمياه على المكونات الغير عضموية والتمي شمملت علمى كمياه الشرب والزراعية ، لقد تم اجراء التحاليل الكيميائ العناصر الرئيسية ، العناصر الثانوية ، العناصر الثقيلة. major componentsالمكونات الرئيسية ان تعيممين تراكيممز العناصممر االساسممية للميمماه يممرتبط ارتباطمما وثيقمما بصممخارية التكمموين ويممتم تعيممين تراكيزهمما ان االيونممات الرئيسممية الشممائعة والمتحكمممة فممي التكمموين الكيميممائي للميمماه , بأسممتعمال طرائممق قياسممية واجهممزة معينممة -so4-,cl-, hco3-,co3ت السمالبة فهمي كأيونمات موجبمة امما بالنسمبة لأليونما +mg2+, ca2+, na+, kهي مختبرات بيئة محافظة النجف االشرف.وقد اجريت هذه التحاليل في miner componentsالمكونات الثانوية وتشمل : -nitrate no3ايون النترات -1 phosphate po4-3ايون الفوسفات -0 heavy componentsالمكونات الثقيلة وتمتاز بعض هذه العناصر epmاو الم ppmتوجد العناصر الثقيلة في الطبيعة بكميات قليلة وتقاس بوحدة بأنها غذاء ٍاساسي لبعض االحياء وعند زيادة تراكيزها عن الحد المسموح بها تصبح سامة ان هذه المجموعة cuوالم coوالم feوالم niوالم znوالم cr والم pbوالم cdالعناصر المذكورة الم بضمنهاتشمل عناصر كثيرة .لعدم وجود فحوصات خاصة بها في الدائرة المعنية ولم يتسنى لنا الحصول على هذه الفحوصات. التحاليل البكتريولوجية ثالثا : 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 23 البكتريا هي مجموعة من الكائنات الحية الدقيقمة احاديمة الخليمة او خيطيمة ، شمعرية الخليمة ذات اشمكال اسمطوانية تسممبب امممراض وعلممل خطممرة وفتاكممة تصمميب االنسممان والحيمموان والنبممات ولهممذا تممم االهتمممام هاان بعضممو او دائريممة، مدى خطورة ووجود هذه االنواع من البكتريا بدراسة بكتريولوجية المياه وخصوصا في نهاية القرن العشرين ل في منطقةالدراسة الكيمياوية للمياه الجوفيةالفيزيائيةو الفحوصات ان المياه الجوفيه تعتبر أكثر صالحيه من المياه السطحيه من الناحيه الصحيه ولذا يفضل االعتماد ال تحتوي علي شوائب تحد من استعمالها عليها كمصدر لمياه شرب صالحه طالما تواجدت بكميه كافيه وكانت بين ت (2, 2, 2ول )اوالجدوهذا االمر يعد من اهم االشتراطات الصحيه الواجب توافرها في مياه اآلبار بين الحد األقصى المسموح بتواجده في المياه تالدرجه القصوى التي تتواجد بها الشوائب المختلفه في المياه كما والحد المفضل عدم تجاوزه لتركيز هذه الشوائب فاذا زادت الشوائب في المياه الجوفيه عما الصالحه لالستعمال هو مذكور في هذه الجدول يتم معالجتها قبل االستعمال حتى يقل تركيزها إلي الحد األقصى المفضل الموجود في نفس الجداول -ما ياتي:يتضح (1رقم )الجدول من لديها ( mg/l 019) ( واوطأ قيمة9( عند البئر رقم )mg/l 5011بلغت اعلى قيمة بمقدار ) (t.d.s) قيمة الجدول رقم ) ( للشرب who( وهذه القيم تقع ضمن الحدود غير المقبول بها وفقا لمعيار )0عند البئر رقم ) كما ويالحظ تباينا مكانيا من بئر آلخر حيث سجلت اعلى تراكيز (2الجدول رقم ) للري isecoومعيار (2 ( واوطا قيم لها عند االبار االخرى كما اظهر الجدول 00, 01, 14, 7, 9, 9, 5, 4لها عند االبار ) ي ف وهي( 9عند البئر )( 11,192بلغت اعلى قيمة لها )( للمياه الجوفية لمنطقة الدراسة ec( ان قيم )1رقم ) للري iseco( للشرب ومعيار whoتقع ضمن الحدود غير المقبول بها وفقا لمعيار ) جميع االبار االخرى ( وهو مطابق للمواصفتين 1.494) حيث بلغت قيمتها 0باستثناء البئر رقم مع وجود تباينا مكانيا من بئر آلخر ( 7.5( الى )11( عند البئر )9.1فقد تراوحت اقيامه بين ) (ph)اما بالنسبة لقيم . انفة للذكر للشرب والري ( وهي حالة شاذة وتعتبر هذه القيم ضمن الحدود 14( عند البئر )19.1( باستثناء القيمة )17عند البئر ) ( للري ومعيار محددات المياه الصناعية انظر isecoلمياه الشرب ومعيار ) whoالمقبول بها وفقا لمعيار ( فقد بلغت اعلى mg( مع وجود تباينا مكانيا من بئر آلخر , بالنسبة لقيمة عنصرالمغنسيوم )9م ) الجدول رق ( وهو في اغلب قيمه يقع خارج 9( عند البئر رقم )09.5( واوطأ قيمة )9( عند البئر رقم )097.4قيمة له ) معيار الصناعة . وخارج isecoللشرب وكذلك معيار who نطاق الحدود المسموح بها وفق معيار مالح الكبريتات فقد تجاوزت اغلب اقيامه الحدود المسموح بها للشرب والري والصناعة بالنسبة ال cl)بالنسبة ) (so4 ) اما )وهو خارج الحدود المسموح به للشرب والري والصناعة ,(ca خارج الحدود المسموح بها للشرب ( خارج 14فجميع القيم تقع ضمن الحدود المسموح بها للشرب ما عدا البئر ) turb)والري والصناعة , العكورة) تقع ضمن الحدود المسموح بها للري وبعض الصناعات , فانها في بعض االبار (no3)بالنسبة للنترات,الحدود 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 ( 02, 19, 11, 4( فانه يقع ضمن الحدود المسموح بها للشرب ما عدا االبار ) doولالوكسجين المذاب ) ( وهي خارج الحدود المسموح 15( فقد تم فحصها فقط للبئر رقم )t.s.s, بالنسبة للمواد او الرواسب العالقة ) ( وهو يقع خارج الحدود المسموح بها naبها للشرب , وضمن الحدود المسموح بها لبعض انواع الصناعات, ) , 9عض انواع الصناعات بانسبة لآلبار رقم ) , وضمن الحدود المسموح بها لب(12للشرب ما عدا البئر رقم ) ( فهو يقع خارج الحدود المسموح بها للري k(, بالنسبة لعنصر البوتاسيوم )02, 17, 19, 11, 11, 12 ( , وضمن الحدود المسموح بها لبعض الصناعات لجميع االبار المفحوصة ما عدا البئر 01ما عدا البئر رقم ) ( فهي تقع خارج الحدود المسموح بها بالنسبة للري ,بالنسبة tempجة حرارة المياه )( , بالنسبة لدر 7رقم ) ومن خالل ما تقدم .فالتوجد مواصفات تذكر لغرض المقارنة( o&gوالمواد العضوية ) (po4للفوسفت ) وذلك من خالل مالحظتنا نالحظ ان هناك امكانية ألستثمار وتنمية المياه الجوفية في محافظة النجف االشرف ( حيث ان المياه الجوفية في منطقة الدراسة موجودة باعماق قريبة ومناسبة من سطح االرض 0للجدول رقم ) الطبيعي بحيث ممكن استثمارها واالستفادة منها لالغراض المختلفة , اما بالنسبة لنوعية المياه الجوفية فقد تم يمكن استخدامها وجد انها حيث (1صة والموضحة نتائجها في الجدول رقم )مناقشتها من خالل االبار المفحو لري بعض المحاصيل الزراعية التي تتحمل الملوحة, اضافة الى امكانية استثمارها بطريقة علمية في الري وذلك المحاصيل باستخدام تقنيات الري الحديثة من خالل فلترة مياه االبار والتخلص من الملوحة واستخدامها لري وخصوصا اذا عولجت بطريقة صحية الزراعية المختلفة , اضافة الى امكاننية استخدامها للصناعات المختلفة ها واستخدامها مرة اخرى كما ان هناك امكانية توعلمية كما يمكن استخدامها لالغراض المنزلية بعد تصفي بارتفاع نسبة الملوحة از مياه آبار منطقة الدراسةاستخدامها للشرب بعد معالجتها بالطرق العلمية الحديثة. تمت ولكن ليس بالملوحة العالية جدا اذا ما قورنت بملوحة البحار , وهي ى وهي ايضا تختلف من منطقة الى اخر من اجل االستفادة منها اذا ما علمنا اننا مقبلون بالطرائق العلمية الحديثة ممكن معالجتها واستثمارها وتنميتها بسبب السدود التركية والسورية. لذلك البد من النظر الفرات رمة مائية كبيرة بسبب انخفاض مناسيب نهعلى از الى مورد مائي اخر وهو المياه الجوفية والموجود بكميات ال باس بها في منطقة الدراسة مما ستوجب الجهات تخدامات المختلفة للمحافظة على المياه المعنية االهتمام بهذا المورد المائي المتاح االستفادة منه في االس السطحية من النضوب. اجاتتنتاالس ان للعناصر المناخية تأثير مباشر على بعض االحتياجات المائية وخاصة ري المزروعات وخاصة من -1 ناحية توفر االمطار وعدمها ودرجة الحرارة والرطوبة والرياح مما يشير الى وجود ضرورة ملحة للبحث بديل للمياه السطحية متمثال بالمياه الجوفية .عن مصدر 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 ان اعماق المياه الجوفية تتغير تبعا لطبوغرافية منطقة الدراسة وكذلك تعتمد هذه االعماق على عوامل -0 طبيعية وبشرية تم التطرق اليها مسبقا. رض مناسبة وقريبة عن سطح اال اعماقمناسيب و ان المياه الجوفية في منطقة الدراسة موجودة ب -1 ويختلف هذا المنسوب عمقًا من مكان إلى آخر, فيكون قريبًا من سطح األرض )المحور االول(الطبيعي بحيث يمكن االستفادة منها لالغراض في المناطق الرطبة الغزيرة األمطار, والقريبة من البحار واألنهار المتمثلة في قع اخرى في موا وبعيدًا عن سطح األرضوذات عمق اكبر في بعض المواقع المختلفة .)المحور الثاني( المناطق الجافة كما في سهولة وانسيابية رسم خصائص ومواقع المياه الجوفية من حيث رسم وتوزيع المواقع المفحوصة للمياه -4 .الجوفية على منطقة الدراسة باستخدام تقنية نظم المعلومات الجغرافية كانية استثمار المياه اماجراؤها على منطقة الدراسة للمياه الجوفية باثبتت الفحوصات الكيمياوية التي تم -5 ةفة كمصدر بديل عن المياه السطحيالجوفية واستخدامها لالغراض المختل التوصيات ان تهتم الجهات المعنية والسلطات المختصة بالمياه الجوفية واعتبارها مصدر مساعد من اجل تجاوز -1 وخاصة بعد اقامة السدود التركية على االنهار العراقية .االزمة المائية المحتملة العمل على تفعيل ادارة المياه الجوفية وذلك من خالل مراقبة االستخدام الجائر لبعض انواعها وان يكون -0 بشكل يؤمن مستقبل االجيال القادمة .خاضع للرقابة الفعلية لغرض استدامتها واالستفادة منها لتقنيات الحديثة لعدام استنزاف الموارد المائية بالري السيحي.تفعيل وسيلة الري با -1 اجراء بعض عمليات المعالجة والفلترة والتصفية لبعض نوعيات المياه الجوفية لتكون صالحة لجميع -4 االستخدامات المطلوبة بضمنها الشرب والري والصناعات المختلفة. رالمصاد المختبرات االنشائية, فحوصات تحريات التربة , بيانات غير منشورة تقارير وزارة االعمار واالسكان -1 0214-0211, للعامين ، دراسة الصفات الفيزياوية والكيمياوية واحتمالية تلوث المياه 0221، محمود عبدالحسن ، الجنابي، -2 جامعة –كلية العلوم –محافظة كربالء. رسالة ماجستير غير منشورة –الجوفية في منطقة شثاثة بغداد. 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 الحياني , عبد الستار جبير, تقييم المياه الجوفية لبعض آبار قرية الخفاجية في محافظة األنبار , -3 .0220جامعة الموصل, -كلية علوم البيئة وتقاناتها محافظة االنبار, –السعدي , محمود عبد االمير , التقييم البيئي للمياه الجوفية منطقة الرحالية -4 0224ير غير منشورة , كلية العلوم , جامعة بغداد , اطروحة ماجست العراق , –عباس ,فالح حسن, دراسة هيدروجيوكيميائية للمياه الجوفية في الجزيرة القريبة من سامراء -5 .0212قسم علوم الحياة, كلية العلوم, جامعة األنبار , كربالء, قسم –ريق نجف العزاوي, بتول دمحم, دراسة هيدروجيولوجية للمنطقة المحصورة بين ط -6 العراق . -الدراسات والتحريات ، الهيئة العامة للمياه الجوفية ، وزارة الموارد المائية . بغداد ، االستكشاف الجيوكيميائي لتجمعات المواد المشعة في 1070المرسومي ، عبدالمطلب حسون ، -7 جامعة بغداد. -كلية العلوم –شثاثة ، غرب العراق، اطروحة دكتوراه غير منشورة –منطقة هيت 0214المهندس صفاء دمحم , مديرية بيئة محافظة النجف االشرف , وزارة البيئة العراقية, -8 0214مديرية دائرة بيئة محافظة النجف االشرف , وزارة البيئة بيانات غير منشورة , -9 -وزارة االعالم -الموارد المائية في العراق وصيانتها من التلوث -دمحم مهدي الصحاف -11 1099-الجمهورية العراقية فرع النجف , وزارة الموارد المائية العراقية , بيانات غير منشورة , -الهيئة العامة للمياه الجوفية -11 0214 التقييم النوعي للمياه الجوفية في منطقة مشروع المسيب ومدى صالحيتها ألغراض دمحم,سعادالهيل , -12 .0227الري, وزارة النقل والمواصالت , الهيأة العامة لالنواء الجوية والرصد الزلزالي في العراق , قسم المناخ , -13 0214بيانات غير منشورة , 14-m. jeihouni, , a. toomanian, m. shahabi, s. k. alavipanah, 2014 groundwater quality assesment for drinking purposes using gis modelling case study : city of tabriz ,iran. 15-stephen t. odonkor and kennedy k. addo,2013, bacteriological profile and physico-chemical quality of ground water: a case study of bore hole water sources in a rural ghanaian community,int.j.curr.microbiol.app.sci 2(8): 2140 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 16-w.h.o., world healthy organization international standard for drinking water geneva switzerland 3 rd edition 1977 p 36 17water resources mongement isiamis educationalg s cientific and cultural organization rabat morocco 1997 p 64 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 14] [(1072-0214) المعدالت عناصر المناخ في محافظة النجف االشرف للمدة :(0جدول رقم ) ]0[في محافظة النجف االشرف 0214-0211مناسيب المياه الجوفية وللعامين :(5جدول ) كمية االشعاع االشهر الشمسي 5سعرة/سم معدل درجات الحرارة الشهري الرطوبة النسبية % سرعة الرياح م/ثا التبخر االمطار/ملم 25.2 20.7 1.7 21 01.3 591.22 كانون الثاني 055.9 15.1 5.5 60.3 13.4 130.12 شباط 510.1 01.2 2.8 51.4 17.9 230.19 آذار 532.2 01.5 2.5 43.7 23.9 239.29 نيسان 219 2.0 2.4 33.4 29.9 221.29 آيار 210.2 0 3 27.8 33.7 220.92 حزيران 229.2 0 3.1 27 35.7 221.19 تموز 213.1 0 2.5 29 35.4 215.21 آب 211.0 0 1.8 33.2 32 212.1 ايلول 523.5 4.2 1.6 43.3 26.4 229.20 0تشرين 022.0 14.8 1.5 29.2 18.2 159.50 5تشرين 32.2 17.5 1.6 70.1 12.65 523.12 0كانون مجموع سنوي 5.5 21.5 52.0 252.29 المعدل السنوي 011.0 مجموع سنوي 1221.3 المنسوب للمياه الجوفية ) اسم الموقع m 5101( لعام ( لعام mالمنسوب للمياه الجوفية) اسم الموقع 5102 (0الموقع رقم ) 2 (0الموقع رقم ) 2.2 (5الموقع رقم ) 2 (5الموقع رقم ) 1.22 (1الموقع رقم ) 1 (1الموقع رقم ) 0.1 (2)الموقع رقم 0.9 (2الموقع رقم ) 00 (2الموقع رقم ) 05.2 (2الموقع رقم ) 5 (2الموقع رقم ) (2الموقع رقم ) 1.2 (3الموقع رقم ) 1 (9الموقع رقم ) 2.2 (01الموقع رقم ) 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 ]9[الخصائص الكيميائية آلبار منطقة الدراسة :(1جدول ) t . s . s o& g po4 do temp turb k na no3 so4 cl ca th as caco3 mg alk.as caco3 t.d. s e.c ph pa 3.2 1.1 1 2.2 52.9 0 19.8 196. 9 0.9 1,118. 7 410 348 0511 80.5 94 2.24 9 1.522 2.5 0 5.7 0.0 9 6.9 25 7 31.4 253. 7 4.03 690.14 580 521 720 29.2 160 1.97 6 3.043 6.8 5 13. 4 1.1 1 2 25 01. 5 33.8 273. 8 1.15 761.5 680 521 911 73.2 172 2.37 0 3.644 2.2 1 12. 4 0.0 9 3.4 2 21.4 3.0 6 89 362 73.2 1,409. 2 1,00 0 448 1,990 212. 2 4,86 7 7,489 6.7 6 2 0.1 2 7.2 20.4 5.3 46.8 347 7.13 1,352 1,15 0 416 1,950 222 4,59 3 7,065 7.0 9 2 nd 4.1 21.1 9.1 4.5 90 27.2 2,004 2,15 0 1,04 0 3,700 268. 4 91 5,65 0 11.17 0 7.5 2 11. 3 1.1 1 7.7 25.3 1.5 83.7 620. 2 124. 7 2,666. 3 1,40 0 660 2,200 27.5 5,91 3 9,111 7.3 2 1.1 1 2.2 50.2 1.9 261. 5 1,04 0 3.45 2,128. 4 223. 5 1,08 0 2,680 239. 1 4.06 0 8.090 8.1 3 1.5 3 4.3 25 8.5 12 102. 1 5.44 256.9 135 162. 4 590 44.8 937 1,464 7.8 9 4.6 0.1 5 7.6 52 5 39.4 20.1 4 23.3 642.5 280 240 820 27.5 1,64 6 2,529 7.8 01 3.6 3.1 27 0.9 50 118 21.7 1,333. 1 310 656 1,87 56.1 2 112 2,97 3 4,574 7.3 00 9.3 0.0 6 9.4 5 22 2.9 63.7 1,523. 6 540 656 2,500 209 3,26 3 5,020 7.4 05 2.8 0.0 6 5.4 22.6 7.5 09 022 3.27 1666.4 7 350 504 1,770 124. 4 2,78 2 4,282 6.3 01 0.0 9 8.1 9 17.5 33. 5 37.4 351. 8 44.3 1,261. 5 370 600 1,840 82.9 6 4,15 2 6,920 17. 1 02 1 0 0 0.0 3 5.2 55 45.5 298. 5 56.7 2,261. 5 223 2,71 6 4,160 7.5 02 0.0 3 5.3 52 6.4 27 228 58.3 8 1,047. 4 221 221 2,080 117. 12 3,59 7 5,531 6.9 02 0.0 6 1.2 1 18.9 22.2 221. 2 20.2 1,430. 4 450 600 1,800 73.2 521 3,32 7 5,547 6.7 02 1.2 4.8 50 24.6 216. 5 1,118. 6 123 5,064 8.5 03 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 ] w. h . o) .)] 02صالحية المياه للشرب وفقا لمعيار منظمة الصحة العالمية :(2جدول ) 0.0 6 6.5 6 20 5.0 6 19 238. 4 61.8 1,475. 8 580 584 2,000 124. 4 3,70 4 6,072 7.6 3 09 5.2 1.1 5.2 0 52.5 0.2 2 15 025 8.3 1,728. 4 552 251 1,800 122 2,81 3 4,021 6.5 8 51 2.0 1.1 2 2.2 51.2 1.2 03 1,547. 5 1,68 5 325 2,940 185. 4 4,82 0 7,400 6.9 50 1.1 2 2.1 1 03.9 21 321. 2 17.0 9 1,192. 3 1,35 0 311 2,700 170. 8 511 4,83 7 7,443 6.5 55 (ملموز/سم.5.52-1.22(بين )ecتتراوح الملوحة) 0 ملغم /لتر 221-521يجب ان ال تزيد نسبة الرواسب العالقة عن 5 عن حرارة الماء في آخر شهور السنة. ºم 1المياه صيفا باكثر من ان ال تزيد درجةحرارة 1 وحدات ( والطعم والرائحة. 2انعدام اللون )اليزيد عن 2 .3.2-2.2بين phيجب ان يتراوح ال 2 ملغم/لتر خالل جميع الفصول. 2ان ال تنخفض نسبة االوكسجين المذاب في الماء عن 2 االجسام والمواد الطافية )كاالصباغ والزيوت(يجب ان تخلو المياه من 2 (ملغم/لتر.52-2يجب ان التزيد عكورة المياه عن ) 3 (ملغم/لتر.511-22يجب ان تتراوح نسبة الكالسيوم بين ) 9 (ملغم/لتر.021-21يجب ان تتراوح نسبة المغنسيوم بين ) 01 ملغم/لتر.( 211-511يجب ان تتراوح نسبة الكبريتات بين ) 00 ملغم/لتر.221-511يجب ان تتراوح نسبة الكلور بين 05 01 t.d.s (ملغم/لتر.5111-)صفر 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 23 ] [18(isecoصالحية المياه للري وفقا لمعيار المنظمة االسالمية للتربية والثقافة والعلوم ) :(2جدول رقم ) 1]1 [محددات المياه الصناعية :(2جدول رقم ) الحد االدنى الوحدة الرمز المقياس المسموح به الحد االعلى المسموح به 5 1 ملموز/سم ec الموصلة الكهربائية 5111 1 ملغم/لتر t.d.s االمالح الكلية الذائبة 51 1 ملغم/لتر ca الكالسيوم 21 1 ملغم/لتر mg المغنسيوم 21 1 ملغم/لتر na الصوديوم 01 1 ملغم/لتر hco3 البكاربونات 11 1 ملغم/لتر cl الكلور 511 1 ملغم/لتر so4 الكبريتات 01 1 ملغم/لتر no3 النترات 5 1 ملغم/لتر k البوتاسيوم bh 2 3.2 الحموضة النسب المسموح بها المادة الصناعة صناعة السمنت كاربونات الكالسيوم حديد منغنيز ph المواد الذائبة المواد العالقة ملغم/لتر.121التزيد عن ملغم/لتر0.3 ملغم/لتر2 3.3واليزيد على 2.9اليقل عن ملغم/لتر051 ملغم/لتر 511 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 23 الكبريتات الكلوريد ملغم/لتر 512 ملغم/لتر 011 الصناعات الغذائية والتعليب كاربونات الكالسيوم ph الكالسيوم الكلوريد الكبريتات الحديد المغنسيوم السليكات النترات المواد الذائبة المواد العالقة ملغم/لتر 111التزيد عن 3.2التزيد عن ملغم/لتر051التزيد عن ملغم/لتر 111 التزيد عن ملغم/لتر 521 التزيد عن ملغم/لتر 051 التزيد عن ملغم/لتر 1.5 التزيد عن ملغم/لتر 21 التزيد عن ملغم/لتر 22 التزيد عن ملغم/لتر 221 التزيد عن ملغم/لتر 051 التزيد عن الصناعة الورقية الرواسب العالقة الحديد الكلوريدات المواد العالقة الصلبة المواد الذائبة كاربونات الكالسيوم ph ملغم/لتر 211التزيد عن ملغم/لتر 2.5 التزيد عن ملغم/لتر 1222 التزيد عن ملغم/لتر 495 التزيد عن ملغم/لتر 0131التزيد عن ملغم/لتر 1272 التزيد عن 0.4-4.9 يتفاوت بين 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 23 قطع االخشاب الرواسب العالقة ph ملغم/للقطر 1التزيد عن 9-2يتفاوت بين صناعة النسيج الحديد المنغنيز النحاس االحمر المواد الذائبة الرواسب العالقة كاربونات الكالسيوم ph ملغم/لتر 1.1التزيد عن ملغم/لتر 0التزيد عن ملغم/لتر 1.2التزيد عن ملغم/لتر 021التزيد عن ملغم/لتر 0111التزيد عن ملغم/لتر 051التزيد عن 3وال يزيد عن 2اليقل عن الصناعات الكيمياوية وشبه الكيمياوية الحديد المنغنيز الكالسيوم المغنسيوم البكاربونات الكبريتات المواد الذائبة الكلوريدات الرواسب العالقة كاربونات الكالسيوم القواعد ملغم/لتر 2التزيد عن ملغم/لتر 5التزيد عن ملغم/لتر 022التزيد عن ملغم/لتر 022التزيد عن ملغم/لتر 922التزيد عن ملغم/لتر 752التزيد عن ملغم/لتر 5211التزيد عن ملغم/لتر 522التزيد عن ملغم/لتر 12222التزيد عن ملغم/لتر 0111التزيد عن ملغم/لتر 211التزيد عن 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 ph 9وال يزيد عن2.2اليقل عن الصناعة النفطية السليكات الحديد الكالسيوم المغنسيوم الصوديوموالبوتاسيوم البيكاربونات الكبريتات الكلوريدات النترات الفلوريد المواد الذائبة الرواسب العالقة كاربونات الكالسيوم ph ملغم/لتر 21التزيد ملغم/لتر02التزيد ملغم/لتر551التزيد ملغم/لتر 32التزيد ملغم/لتر 511التزيد ملغم/لتر 231التزيد ملغم/لتر221التزيد ملغم/لتر 0211التزيد ملغم/لتر3التزيد ملغم/لتر0.5 التزيد ملغم/لتر 1211التزيد ملغم/لتر 211التزيد ملغم/لتر 911التزيد 911واليزيد عن 211اليقل عن 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 [ علىاالشرف المصدر: الباحث باالعتماد يوضح المواقع المفحوصة في محافظة النجف :(0الشكل رقم ) [1 6202 2العدد 9مجلة القادسية للعلوم الهندسية المجلد 22 [9]المصدر: الباحث باالعتمادعلى ( يوضح اآلبار المفحوصة كيمياويا في منطقة الدراسة0الشكل رقم ) ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٢ �� ����� �� � �� # "�� ا����و�� ا� �ار�� ���دة ��آ � ���اة ������ف ������ام � ��دة �(��� �ّ)َ&$ .�+*� ا� � إ,�+� ��دة �� �� �ّ��� وه( )�رات ا�%�$ #�" ���و�� ا�ّ��� ���دة ��آ�� ����� �� ./0 � 40 +( ه3ا ا��12 درا 2b � ) 0°-90°(����ى )/� �ف ا���ر)�ن .��: � ا8��09را0�7 ا�6 ��ل +�ر����ه � ا �+�c225)ذات آg/cm3( . 1 f $�g(ة و�hا���� �ارة ا�ّ���f �� � iوا � 2b ���j k�h "�# $�%40 إ,�+� )�رات ا�(4mm) ا���دة lb "�# ��n ا�2�ار�n وا�3ي�oر ا���opإ q �b0 qn�j �# �nار� �g0 ��uon t ّ��� ا����s ا���آ�� وi �س ��ى ���و�o�� ا�2 �6�ov� ض� ودرا � ��ى 0/.� (25mm,20mm,15mm,10mm)ا��yز�n #�" ا����b ا��� �� �ّ��� و)��g+�ت �0 lbgارة ا��f �zدر � ( �i[ا�� kc�0 )oا� � �� ت ا���bbvا�� )+ l,�� وآ�� ��o20 ��iآ�� ا��ا�ا���دة ا�� ks6ا� � ض �2��oوز�� ا� �ض �ّ����oا��.f 7:�o�ت ا�� ز�nدة ���و�� ا���دة ا���آ�� ��2�ارة ا���� � �^ 1 أ\� .�g20 ا����و�� �so�9ر ا�ّ��� )%�nدة ��g0 �+�g t ا����sو إ,�+� )�رات ا�%�$ . ا����و�� ا�2�ار�n ، ��دة ��آ�� ، ��دة �� �� �ّ��� : ا��)��ت ا��ا�� improving thermal resistance for composite material reinforced by fibers by using flame retardant material layer dr. kareem d.jaseem technical institute-diwaniya mechanical department ali i. al-mosawi technical institute-babylon mechanical department dr. abbas a. al-jeebory al-qadisiya university college of engineering abstract in this research we studied the effect of flame retardant material addition which is zinc borate on the flame resistance for composite material consist of phenol formaldehyde resin reinforced by woven roving carbon fiber(0 o -90 o ) with (225g/cm 3 ) density . where we added zinc borate as a protected surface layer from direct flame with (4mm) thickness on the surface of composite material and measuring the rang of its thermal resistance by applied thermal erosion test , which included exposition the flame retardant layer direct flame gas torch (butane-propane) with different exposed distances (10mm ,15mm ,20mm,25mm) and study the influence one substrate composite material as illustrated in the diagrams between surface temperature and time . keywords: composite material , flame retardant material , flame resistance . 3)2 إ��اه�/ ا�����ي ���6-ا��(&� ا���24 3 �س 3)��ي ا�7 �ري .د ��9(� ا���د��� آ��/ دا:6 �9�/.د د��ا��� -ا��(&� ا���24 ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٣ i – ����� .)introduction( ا� ����g0 )oا� �nوا���د �n�sا�� �:�gvر وا��bpb#�" ا��2 �� ا � ة +( ا��12 #� ��اد ��� ا���)��nا%oا�� � ه�c� �� o� ��12 #� ��اد ��� ا���رة #�" ���و�� ا���� ا�����o �� ا�2�ا:q و+( �e6 ا��k��0 di آ��دة ا�2�ا:q وآ�3$ ا �voام ��اد آ � �: � ��0^ ) � ا��%ل ا�2�اري و���و�� اا�ّ��� �0ُ�ف g( � #��hت ا��g iز�� ، ��3$ )�أت ا���# �ء أو )�� h0� ^ ا���اد ا���اد on��f�� وا�o( �u0ف أ.� )materials flame retardant( )����اد ا��� �� ا�ّ��� �اق of9ا �� .ln��0 ���n�hا���� ��mا�� k�20 "�# ا���رة ��� � :� � #�" إ��� ��اد آ �ت ا�ّ���� �� k��0 1 f )k�s ���:( ، و�u0ف ا��� �� �ّ�َ�ْ� إ�" ��اد � e ��� ا���رة ��^ ��6ذ8 داkp ا���دة و��^ إ��soر8 وof" إ��pد8 #�" #�nار� ] . ٢٠٠٣،#�( إ)�اه 4 [�" ���و�� ا�ّ��� �g2o � �pاp�� ا�2 ��ب اbول #�" ��^ و�pل اbوآ�g � إ�" ����b ا���� #� bا ��o�nو �ا�ّ�� �i�#9 و+�ن�ه���$ إ ��)�ن �� �اق f �g0 1� ه83 ا��yزات +( 4�g0 اا�ّ��� )���3ور ا�2�ة وإ��pد8oft� ��(�i � u زات�u � ��0 qn�j . أ�� �i�j "ج إ��o20 ���ّت ا��� إن �� "�# w�0 )oوا� �nار���n اo�9��ب ا�2x� "�# ��o�n y�g+ )��cب ا��� ا9 li�on )��o��(إ��0ده� و �zدر �� kiارة أ�f �zا���دة إ�" در lb �ارة f z6p "دي إ�in ��� $�6o0 )آ �nار�f �اق of9ا] %n%# م� .] ١٩٩٣،اآ ّ��� أو of" إ�j "�# ��o�0 y+��n �� ا���دة ا��� �� �ّ��� ، f ���n 1 أن k��0 �� ��ت ا�ّ��� إن #�� � إ#��i ا� �اق p]ل :آ � �of9ا � ^ #��� �ّ��� �� ا���دة ا��� kpا�o0 إذ ، �nز�yوا� ��:�gوا� ���hا����2 ا� )+ �ً :�n% + أو �ً � vgoء ا���أ. �p} و)�]م � �6 �� ه83 ا�����ov� kfا� وا��6o$ أو ا�k�2o وا��oh9ل أو إ��soر ا�ّ��� � ]troitzsch,1998 . [ qn�j �# ل��oht� � �(ا��� ��� )oل ا~�� ����اد ا����o 9�( l� إن �b0ر �� ��ت ا�ّ��� ��iا�ofل إ��� z6pل و��oht� ��o �(�i z6p . ن و�� o�b�6ر واg6ا� �p��# "�# ���ّت ا��� 4 ��x�� ي�o20 � ا���اد ا��u0ُ )oف إ� �� �� ��ت ا�ّ��� ه( ا���ا:� ، ا��g�b ، ا����ر cأآ �� � zو�o�وم و ا���رون وا��و ا�� �ىpو��اد أ � و��o��9ا � ] .٢٠٠٣،#�( إ)�اه 4 [وا��وا: .)zinc borate( ��رات ا�=�> �n�uا�� � u ���ّت ا��� رات ا�%�$ إ�" ����#� ���( )�o�0)inorganic flame retardant materials ( ���n ���رات ا�%�$ أن k2� k20 أآ� � اo�b ��ن آ�� q ّ��� . وا��vog0 )oم ��n��2 ا���اد ا���ا:� � �� ا�ّ��� �ح ا��3ور ا�2�ةj �b #�� . �62% +) ا���ا:� وا���bط f k��0 1 #�" ز�nدة +��� � إ#��i ا�ّ��� اbو� � �(ا �0�ض ه3ا ا���ع �� � kc� ل��oh[� ��(�i � u زات�u ر�2nو k�2on وإ��� �v�on � y�g+ ارة�� ��ت ا��m�� إ�" ا�2 �ه� �� ا��yزات uو � zرو� ا�� �nوآ��ر dn�)�vر ا���ء و.��) ُاوآg � ا���ر�(ن و.��( ُاوآg � ا��� ]troitzsch,1998 . [xة +( ا���ogر و����o� z (�2ق أg� k�h "�# $�%��0ن )�رات ا� ، �nد� o#9وف ا� ]. ٤ )[g/cm3 3.64(وآ���0 �+�c ) c °980(و�o�0$ )�رات ا�%�$ در�z إ�h��ر ���0 2�ارة�� �p�� آ��ت �60#]ت�� ه83 ا��c7 أآo�n)endothermic reactions . ( ����60 "�# ����# � �} ��o�0 i � u زات�y� ه��n�#�" 6v0 7n%� l ا��yزات �)�� ���ohtل k��0 +( در�zت ا�2�ارة ا���� � ��� inدي إ�" 20 "�# � ��f � z�zز ���j آ�3$ ��0ن � �gوآb�( ل�h09#� ا � �ا���دة ا���ا: lb ا���)�� ���ohtل و�� .4 #%ل z�( l,�n )١(ا��7ول ر</ . ]troitzsch,1998[ا����b ا��6g � ����دة �0�^ 0/. �ات اbوآ�g � وا�2�ارة . �$ �pاص )�رات ا�% � �آ� .)composite material( ا���دة ا� �nد 0/ر��n )ا��f )6+ ��nر ا����hآ�� إ�" ا���إ �voم ا���)� �ن ��دة ا���o +( ) م. ق٥٠٠٠( h0� ^ ا���اد ا�� ��� وآ]ه�� �� ا���اد ا���آ�� �vو��ن ا��رق وا��( #�[�n��0 ا�b � ا�3ي �vognم ����ء ا����زل وآ�3$ إ �voم ا� ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٤ � l�ov0 +( �pاp�� ] . ١٩٩٩ ،ه�)(cأو أآ � ن �� د�7 ��د0��o0 آ�� #�" إ��� ��دة��0�ln ا���دة ا�� ���n � �pbة +( ا���اد ا�+�o� ��0 4� ة�n�z اص�p ط���o �ض �� ه3ا ا���^ ه� إyوا� ، � :�n% 6وا� � � ��� ا��] )�# ��n أ �] . ٢٠٠٣،إ)�اه 4 h�# �� آ��� � ه�� ��o0ن ا���دة ا��: �س -١b)ا���دة اmatrix material(. ku+أ ��o�0 )oوا� � ��ا0��ا� � � ، وا���اد ا� g، ا� � ة ه( ا������n�# ة و��0ن #�" أ��اع��ogا���دة ا�� kc�0و ��on��0 � ����g( % �o0 ة ، آ��� z �nار�fو � � ��� اص ��p �� y( ز�o�0 ��� س� bا���اد ا�f �gآ ��( � 6( )/آ� "�# ��c�bو�� ا ��� �h0 ���� �ا� � � إ,�+� إ�" إ��6vض آ�o6�� و gوا� � س ا������ bر�� �^ ��اد ا�����( �o � را0�7 ] .١٩٩٩ ،#�( ه�)([ا���اد ا��ا0�� � ه� را0�7 ا�6 ��ل +�ر����ه � ، ا��n9آg( ، وا����( أ�o�n vogت ا�����ا0�� ه3ا ا��ا0�7ا�6 ��ل +�ر����ه � �� أ�iم ا� u20 4on 1 f ، �ً vnل �^ ��� 0/ر�� ا�6 k#�60 �� ��o�0 70��7 ا��ا0��آ��ت c�0 6 � وا����k ا��62% ا���vogم أ�� z��f أو �i#�ة و�j �� ا�� )b� � � ا��6ر����ه ��#�6oا���اد ا�� � ( � �n%ا�� �g�م و#�" ا��vogع ا��62% ا���� "�#)� ل وا��6ر����ه�� 7 ) . ا�6�م را0�vogn �ار�n و#%ل f ز )���و���o�0 (oا� � و#bج ا�oإ� ���و� � #��hت ا�� ا���� �� � c+( ا�� � ل +�ر����ه�� ا�6 ���j ن�� إ�" ا���ر)�ن � � ارة ا�����آ��)�:( وآ�vogn $�3م +( �b0 ��ت ا��u6ء آ���2on yل +( در�zت ا�2 �ه� �� ���26o #�ز�� و��f � ������ ا����ك ا��u6:( و uى�pbُت ا�� �boح [ا��o66 ر</ . ]٢٠٠٠،#�� ا��cا� �آ � ا�� � �:()١(oا� l,�n 7�0ا� . ا�6 ��ل +�ر����ه � � ٢ �n��oدة ا���(reinforcing material). o � +( ه83 ا���اد وه( ا����و�� ا���� � وا��b � � ا���bog0 "of �u6v �n��0 ^ ا���� � � %0 � أ+�0 ��n دة �cأآ ��o�0 )oف وا�� �b�( �n��oوا� ، doso��( �n��oا� ، q:�i���( �n��oا� ���� �n��o�� ة�n�# ق�j $���س ، وه� bا �ًا ��� �o0 �i �� y( %ة آ� �ة ���ر�� )����اد ا��ا0�� � x� �ً#� h �n��oا� � �� ��0ن ا�b �ف )/��اع وأ��hل . أ � أو�og� k�sن )��n �� ����+ �6�ov� ف� ه( أ� �n��oف ا�� أ� "�# ��c�b�2آ� و�� ا� �:�6\ k�s( أو ^b�� h0�^ أ� �ف ا���ر)�ن �� ا�426o وا�k�2o ا�2�اري ��ا0�7 ا����( . ]dewit,2000[ا���ر)�ن وأ� �ف آ 6]ر �ارة f �zدر )+ kn�o���n��ات ا���j)� ودر�zت ا�2�ارة +�ق ا�c)°(2600أآ ./o� � ��# و�����( lho0ى و�� �b(ا� . ]horacek,2000[ا�3ي 4x�� y( k��0 ا���اد ا� .) thermal erosion test( ا��(��� ا� �ار��ا:� �ر �nار� وا�3ي �vognم )٢(ا�6�c ر</ ، وا���,�} �2 torch test ( )+ yo( و�gn" أunً� إ��opر ا����s ا�2 �ار��# �n � ��o0وز ����ازل ا�2�ار�n ا�k�2o0 )o در�zتf )3000ºc ( ت�zل #�" ه�3ا در�h23ر ا��on إذ � ��o� �nار��qn أz�%ة i �س ا����p � ا�2�ار�n ا�#o �د�vog0 $�3� �nم أ��اع ��6�ov �� ا����s ا�2j �# �nار�f �6�ov� �nار�f ت�zدر .n $�3� �nار��ق +) ه3ا ا��op9ر ��nن �� ا��gf �(��hب ����k ا����p � ا�2j "إ� /�� ��o�nن ��g2ب �iرة ا���دة #�" ���و�� j ك��وه � ارة ا������ى ��g2ب ��ى ا��%ل ا�2�اري +( در�zت ا�2pُا ��o�nن ه��bاري وه��0ن ا���ارة ا�ّ��� ا���� � و���ار #%��� ا�2f: ١lbgارة ا��f �zب در�gf (surface temperature). �4on، ��n و,^ �2�اbل +( ه83 ا�[p ���o�ارة ا����+� ���ار ا�2��� ���sا� l�p ^iا��ا lbgو�( #�" ا��o� ر إ� ].horacek and garabner,1996[ا���زل ا���دة �ر-٢uا� q�# ب�gf (depth of damage). �ر +( ا���دة ا���ز�� uا� q�# س��n �� �� � �ة ز��o6� �nار��اقإ��ى ( )�� �g0 t ا����s ا�2op ].tran and etc 1997) [ا����s ����دة ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٥ e .ا���اد ا��"����� 2f ا� � ��oام ا���اد ا��vo :40 +( ه3ا ا��12 إ ).flame retardant material( ا���دة ا��� �� �ّ���-١ �آ� وا��(2zno.3b2o3.3.5h2o) ذات ا���% 40٢٣٣٥ إ �voام ��دة )�رات ا�%�$ h k�i �� ة%��)c-tech corporation ( ���ّا� �i�#ة #�" إ� z رة��( ^o�o0 )oوا��7ول ر</ وا�):( ���رات )٢� � ا�� � آ�oا� l,�n )+ ���vogا��12ا�%�$ ا�� . . 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(www. chemical land21.com). ٥-4 �f )(ه� )�# ”ة�gا��� � �اص ا���اد ا���ا:�p � g20 “،� ogz�� ��� ،ا���اق ،k(�( ����z ، آ� � ا���� �،ر ١٩٩٩ . �ت #�4 و�0� � ا�����ات“ #�� ا��o6ح ���2د �jه� . د-٦� � ، ا���nض ” أs��� �n� ا������ ا���) � -دار ا�� ، �nد��g٢٠٠٠ا� . ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٧ 7-cynthia a.dewit “ brominated flame retardants ”, swedish environmental protection agency ,2000. 8heinrich horacek and stefan pieh “ the importance of intumescent systems for fire protection of plastic materials ”, polymer international ,49,2000. 9h. horacek and r.grabner “ advantages of flame retardants based on nitrogen compunds ”, degradation and stability 54,1996. 10huy k. tran , christine e. johnson , daniel j. rasky , and frank c.l hui “ phenolic impregnated carbon ablators (pica) as thermal protection systems for discovery missions ”, nasa technical memorandum 110440 , april 1997. ]٤[�(v :�اص ��رات ا�=�>:) ١(ا��7ول ر</ mol wt ph density g/cm 3 melting point °c appearance property ٧.٦ ٤٣٤.٦٢ 3.64 980 white crystalline value 2 � �رات ا�=�>: )٢(/ ا��7ول ر<m��� ا���آ�$ ا��� water of hydration boric anhydride zinc oxide compound h2o b2o3 zno symbol ٣٧ ٤٧ ١٤ percentage content 4iر k�s:)١(ا� � ل +�ر����ه�� 7 ا�6�ا0��آ � ا�� � �:( �o٦[ ا�[ ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٨ 00.0000 $ ��co d ا����s # �� ا��op9ر�� ���( 4�2o�� م�vogn q�%�� �nار� ا�� �� #� ا����s ا�2 z��ز i �س در�z ا�2�ارة l�p # �� ا��op9ر ����s ا�2�ار�nا �اريf دوج%� 4iر k�s٢(ا� : (�nار���n ا�2�oر ا���opإ ار�� ���ذج إ:� �ر ا��(��� ا� � :)٣(ا�6�c ر</ ������� ���� ��� ������� ���� ��� ����� 4mm 6mm 0 5 10 15 20 25 30 35 40 0 20 40 60 80 100 120 140 160 0 5 10 15 20 25 30 35 40 45 50 55 60 0 20 40 60 80 100 120 140 160 time , sec s u rf ac e t em p er at u re , º c time , sec s u rf ac e t em p e ra tu re , º c ��� �����)�( ��n ا�2�ار�n ���رات ا�%�$ �oر ا���opإ �g�(10mm)+� ا��op9ر ��� �����)�( �oر ا���opرات ا�%�$ إ��� �nار���n ا�2 �g�(15mm)+� ا��op9ر ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٤٩ 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 0 20 40 60 80 100 120 140 160 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0 20 40 60 80 100 120 140 160 time , sec s u rf ac e t em p er a tu re , º c time , sec s u rf ac e t em p er a tu re , º c ��� ���� )�( إ:� �ر ا��(��� ا� �ار�� � �رات ا�=�> �ر �:gا �f�"�(20mm) ��� ���� ) ( إ:� �ر ا��(��� ا� �ار�� � �رات ا�=�> �ر �:gا �f�"�(25mm) article al-qadisiyah journal for engineering sciences 13 (2020) 001–006 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hind.shabbani@qu.edu.iq https://doi.org/10.30772/qjes.v13i1.644 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. a review of co2 adsorption from ambient air (direct air capture) hind jihad kadhim shabbani a * a department of materials engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 21 november 2019 received in revised form 02 january 2020 accepted 23 january 2020 keywords: adsorption adsorbent isotherms a b s t r a c t direct air capture (dac) has risen in the past decade as a promising choice to remove co2 directly from ambient air. although there are many technologies like pre-combustion, post-combustion and oxycombustion to mitigate the emissions of co2, there is still a need for a better or a complementary technology in controlling these emissions. even though, there are many options for adsorbents that can be used, metalorganic frameworks (mofs), which are hybrid materials with a crystalline structure, tunable pores, and high surface area, have risen as a promising candidate. functionalizing mofs with amine groups will greatly enhance their capacity towards co2, like mmen-m2 (dobpdc) (m=mg, fe, mn, zn, co). these adsorbents show s-shaped adsorption isotherms and have a very high affinity to co2 under atmospheric conditions, due to the cooperative insertion of co2 into mmen-m2 (dobpdc) that leads to their unique adsorption isotherms. the energy required to regenerate these materials using small heat variations makes a better choice than aqueous amines. this mechanism has been studied by using x-ray diffraction (xrd) and spectroscopy experiments. furthermore, a thermodynamic study has been reviewed to understand the mechanism through which co2 is inserted into the diamine bond. these materials are a promising choice for the removal of co2 directly from the atmosphere and require more future research. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction there is a growing acceptance that global warming is real and that human activity is partly responsible for it. as industrial life has thrived, greenhouse gas emissions have also thrived with it. carbon dioxide, which is an important greenhouse gas, has experienced a steady increase in its atmospheric concentration from 280 ppm into 400 ppm, since the start of the industrial revolution as a direct result of the burning of fuels and power generation [1], [3-5]. although the subject still under debate, some strongly advocate that present concentrations of carbon dioxide do play a major role in the warm-up of the earth's atmosphere, resulting in the reduction of the sea ice at the poles and the increased water levels [1, 2]. for example, figures (1) and (2) respectively show the most recent results related to both the arctic sea ice extent and the global (both land and ocean) temperature index from the national snow & ice data center (nsidc). in both cases, the graphs show that we have reached unprecedented records. if human activity is to be indicated as playing a major role in the presently observed trends, then the causes that lead to present co2 concentrations need to be addressed. recently, for example, the intergovernmental panel on climate change (ipcc) have suggested that emissions need to be reduced by 30-60 % in the next 35 years [6]. although there are many types of research going towards the development of technology for using renewable energy sources such as solar, wind, geothermal, etc., fossil fuels are still providing almost 80% of the world's need for energy. today, depending on how co2 emissions are generated, co2 removing processes have been defined according to three different categories: those that are pre-combustion, those that are post-combustion, and those that are oxy-combustion. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 2 authors /al-qadisiyah journal for engineering sciences 13 (2020) 001–006 figure (1): arctic sea ice extent as of january 2, 2017, along with daily ice extent data for four previous years[7] figure (2): global land-ocean temperature index[7] in pre-combustion processes, co2 is removed from a stream before its conversion into the flue gas. this method is typically used in industries involved in the production of natural gas, h2, and syngas [1],[6], and [8], such as gasification, sweetening, steam reforming, and water gas shift reaction. in post-combustion processes, co2 is removed from streams with no energetic value or flue gas, which, as the term indicates, is carried out mostly after a combustion process has taken place [1], [6], [8], and [9]. this type of processes is intended for downstream processing of fuel-based energy and power generation units typically found in the industry and power plants. however, co2 removal processes meant for the cemented steel and aluminium industry can also be included in this category. finally, in oxy-combustion processes, nitrogen is excluded from the combustion processes via oxygen purification resulting in a flue gas consisting mainly of co2 and water vapor [1], [6]. in addition to these three categories, there are other more recent approaches to co2 capture. one of such approaches is the direct air capture (dac), wherein co2 is captured directly from the air at ambient conditions [3], [11]. the concept, which was proposed by lackner [10], has been attracting significant attention in recent years. although this technology is considered in its infancy, it shows promise mainly because of its location flexibility as units can be incorporated in any place [1], [10-12]. further, ambient air is rather free of sox and nox [10], which usually react with adsorbents irreversibly. on the other hand, the major limitation of dac is the small concentrations of carbon dioxide, resulting in significantly low collection rates and very small yields and throughputs when compared to the more traditional ways of collection mentioned earlier. despite this, it is worthwhile reviewing the present efforts toward the development of this technology. this is the intention of the present work. solid adsorbents are being widely proposed as an alternative to aqueous amine solutions due to the lower energy required for desorbing co2 [4]. the metal-organic frameworks (mof) are excellent candidates for dac because mofs are porous solids that are promising alternatives to due to their large surface area, tunable pores, availability of open metal sites and their high likelihood to be produced on an industrial scale[4],[13-15]. the adsorption capacity of these adsorbents towards co2 at ambient pressures can be improved significantly by introducing alkyl diamines into the pores of unsaturated sites of these adsorbents [16]. functionalization of metalorganic framework mof with alkylamine can greatly enhance its adsorption capacity towards co2 [14], [16,17]. mcdonald introduced synthesized two mof zn and mg; dobpdc4-=4,4'-dioxido-3,3'biphenyldicarboxylate via solvothermal and microwave method which is reported in the literature [17,18]. then the mof was functionalized by introducing n, n'-diethyl ethylenediamine (mmen) to afford mg2(dobpdc)(mmen)1.6(h2o)0.4 (mmen-mg2(dobpdc)). after the materials had been synthesized, powder x-ray diffraction was performed to get information about the dimensions of the unit cell of these materials. the amount heat of adsorbed co2 (mmol/gm) was calculated at a temperature range of 25,50 and 75°c using longmuir-freundlich eq. while the isosteric heat of adsorption was calculated using the clapeyron eqn. also, the purity and co2 selectivity were calculated [17]. the sample was regenerated to 150 under vacuum for one hr, then followed by thermodynamic analysis and gas cycling using thermogravimetric analyzer tga at a flow of 15% co2 in n2 atmosphere flowing at a rate of 25ml/min and ramp rate ranging between 5-10 °c. other physical measurements were also performed to get extended information about the sample. figure (3): synthesis of mmen-mg2(dobpdc) (mmen = n, n′dimethylethylenediamine;dobpdc4−=4,4′-dioxido-3,3′biphenyldicarboxylate). green, red, and gray spheres represent mg, o, and c atoms, respectively; h atoms are omitted for clarity. amineappended co2 adsorbent mg2(dobpdc)(mmen)1.6(h2o)0.4 (right)[17] nomenclature dac direct air capture iast ideal adsorption theory mofs metal-organic frameworks authors /al-qadisiyah journal for engineering sciences 12 (2019) 000–000 3 after performing the experiment, it was seen that the functionalized mof had a capacity 15 times higher than that of the unmodified mof, the modified mof adsorbed 2mmol/gm at 0.39 mbar and 3.86 mmol/gm at 1 bar, which shows a remarkable affinity towards co2. although the modified version of mof has a higher adsorption capacity towards co2 than unmodified mof at low pressures than at higher pressures,20 mmbar, due to large density difference [17]. the calculated heat of adsorption was less at lower coverage and increased until it reached a value of -71 kj/mol, which is an indication of chemical adsorption due to the formation of the c-n bond of a carbamate that is probably formed. this is also proved by performing infrared spectroscopy, which shows an apparent loss of 3316 cm-1 due to nh stretch. the presence of amine groups is necessary to stabilize the formed carbamate [17]. the slow desorption at room temperature is an indicator of the formation of the ammonium carbamate since the latter desorb co2 at room temp. but is not conclusive [17]. further investigation for the role of the neighboring amines is required. the sshaped isotherms are not expected in these materials due to the material has strong adsorption of co2 as well as large pores, which means that co2 should have been adsorbed on the mmen before being greatly adsorbed on the other weaker sites [17]. this can be hypothesized that the co2 adsorption on the mmen is not favored at low concentration of co2 in the pores due to need to chemically adsorb co2 which will require reorganization of the amines which will be associated with large positive entropy and as the thermal motion increase so as the minimum chemical potential that is required for the reorganization or the amines increase with it as can be seen from the shift in the isotherms at higher pressures and temperatures [17]. this hypothesis went through the further investigation as will be explained later [4]. the selectivity of the mmen2 towards co2 is studied in comparison with n2 and o2, and the result was underestimated due to the inability to use ideal adsorption theory (iast), which is a mathematical model developed by myers is independent of the experiment results and actual data [17], [19,20]. these materials showed a very high selectivity towards co2, on the other hand, they were able to achieve 96% purity under direct air capture conditions [17].although this purity under actual conditions of operation in the adsorbent bed will be affected by different factors, but in adsorbent bed of 80% void volume the purity of co2 will be over 90% [17]. the renewability of these materials have showed a great promise in reducing the regeneration energy because even though 1.05mmol/gm were adsorbed only after flowing air at atmospheric conditions for an hour, no loss in capacity was noticed after regenerating the sample with n2 at 150°c for 30 min and repeating the cycle for 10 times 17]. these materials also have fast kinetics, even though polyethyleneimine impregnated silica gel was able to achieve 2.4 mmol/gm adsorption capacity, but it took almost 4 hours while mmen2 was able to achieve 1.05 mmol/gm in one hour. in conclusion, these materials show high selectivity and capacity towards co2 under atmospheric conditions, but the mechanism at which co2 is adsorbed needs to be further investigated. mcdonald et al. explained the mechanism that leads to the step-shaped isotherms is due to the cooperative co2 insertion to the metal amine bond [4]. x-ray diffraction at 100 k before and after five mbar co2 exposure on the mmen-mn2 (dobpdc) was performed to get structural information on how co2 binds with these materials. they found that full insertion of co2 occurs the adsorption of co2 on these metal sites into the mn-n bond resulting in a carbamate with one o atom bound to mn and the other o atom bonded to n atom from a neighboring mmen resulting in chains of ammonium carbamate. the x-ray helped them formulate a detailed mechanism to explain the adsorption of the co2 in these phase change adsorbents. in the presence of co2, the amine of the mmen molecule to act as strong base leading to deprotonation of the acid gas followed by nucleophilic co2 addition resulting carbamate formation in which the m (m=mg, mn, fe, co, zn)-n bond and the formation of the m-o bond. this cooperative effect will propagate until 1d ammonium carbamate chain has been formed and this effect is the cause of the high co2 adsorption capacity due to full accessibility of co2 into the pores unlike other adsorbents in which the main mechanism gate opening that hinders the co2 into the pores due to the presence of flexible hydrogen bonding functional groups[4]. figure (4): powder x-ray diffraction structures of mmenmn2(dobpdc), a portion of the crystal structure of the final configuration of co2 adsorbed within mmen-mn2(asdobpdc), depicting the formation of an ammonium carbamate chain along the pore surface. green, gray, red, blue, and white spheres represent mn, c, o, n, and h atoms, respectively; some h atoms are omitted for clarity [4]. they also performed infrared spectroscopy to confirm their conclusion on the adsorption mechanism. the results of the spectra are shown in figure (5) below: figure (5): infrared spectra on dosing an activated sample of mmenmg2(dobpdc) (black) with co2 and cooling from 150 ͦc to 30 ͦc (red to blue) under 5% co2 in n2. the three different regions show bands corresponding to n–h (left), c–o (center) and c–n (right) stretching vibrations[4] in the infrared spectra, the adsorbent was cooled under constant pressure from 150 to 30°c at a rate of 1 degree per minute under 5% flowing co2 in the n2 environment. the n-h bond that could be noticed for the higher temperatures at 3,258 and 3,334 cm-1 is resulting from the presence of the mmen ends. the breaking of the n-h bond due to the presence of co2 (c=o at 1,690 cm-1) and the formation of amine n-h bond of the carbamate can be observed even at high temperatures. the infrared showed that the forming of ammonium carbamate is what gives the s-shaped isotherm for co2 adsorption. they also performed near-edge x-ray adsorption fine structure of the nitrogen k-edge mmen-mg2(dobpdc) under co2 pressure, and they were able to prove their proposed mechanism[4]. according to tat mechanism, the different metal amine strength offers different isotherm step position as they demonstrated by synthesizing different compounds of m2(dobpdc) (m=mg, mn, fe, co, zn, ni) and performed adsorption for various temperatures ranging from 25-75°c. the detailed method of volumetric adsorption isotherms calculation and equations are mentioned in detailed in literature [21] . the results showed that mg, mn have the highest step position isotherms due to their long amine bond length 4 authors /al-qadisiyah journal for engineering sciences 13 (2020) 001–006 (~2.45,2.35 a° respectively) and they are suitable for adsorption co2 from natural gas under pressure as low as 0.05 bar. the only metal that didn't have the stepped shape isotherm is nickel but instead had a regular langmuir isotherm due to the high stability of the ni-mmen bond preventing the cooperative effect from taking place. figure (6): carbon dioxide adsorption isotherms at 25 c (blue), 40 ͦc (blue-violet), 50 ͦc (red-violet) and 75 ͦc (red) for mmenmg2(dobpdc) (a), mmen-mn2(dobpdc) (b), mmen-fe2(dobpdc) (c), mmenco2(dobpdc) (d), mmen-ni2(dobpdc) (e) and mmen-zn2(dobpdc) (f)[4]. it is not just the adsorption capacity that is important but also the working capacity (the amount of co2 removed from the adsorbent) on performing regeneration in pure co2 over ten cycles of adsorption in which mmenmg2(dobpdc) and mmen-mn2(dobpdc) were exposed to 15% co2 in n2 atmosphere at a constant pressure and temperature ranges from 100 to 150°c for mmen-mg2(dobpdc) and 70 to 120°c for mmen-mn2(dobpdc) , the working capacity was 13% for mmen-mg(dobpdc) and 10% for mmenmn2(dobpdc) with no loss in the adsorption capacity over these ten cycles. the regeneration step is energy conservative in which it requires (2.2-2.3) mj/kg co2 captured, unlike other commercial adsorbents like aqueous amines. figure (7): cycling data for a pure temperature swing process involving adsorption from a simulated coal flue gas (15% co2 in n2) at 100 ͦc in mmen-mg2(dobpdc) (c) and 70 ͦc in mmen-mn2(dobpdc) (d), followed by desorption at 150 and 120 ͦc, respectively, using a flow of 100% co2[4] wu et al. performed a study on these same adsorbents (mmen-m2 (dobpdc)) to further understand the thermodynamic mechanism of co2 adsorption on these materials [22]. they performed an experiment for three different temperatures 298, 323, and 348 ͦk using a calorimetry apparatus. figure (8): adsorption calorimetry apparatus [22][23] the material was put in a silica glass tube and subjected to vacuum for the day and a half at a temperature of 373 ͦ k. the enthalpy of adsorption and the isotherms were recorded at the same time; this will help in determining the heat of adsorption as a function of the surface coverage. to fully explore the co2 adsorption mechanism on the mmen-mg2(doodc) the experiment were divided into three sets: firstly the adsorption and adsorption after regeneration under vacuum were conducted to investigate co2 reversibility, secondly after the second round on fresh mmen-mg2(dobpdc) the regeneration was done only by degassing without using heat to keep the chemisorbed amount of co2 and remove the physisorbed ones, finally the enthalpies of adsorption were measured at the experiment temperature range [22]. these materials have great reversibility with marinating the adsorption capacity towards co2 with no change in selectively since the isotherms and differential adsorption enthalpy overlaps. this makes them very cost-effective regarding the energy required for regeneration [22]. the third round represents the amount of co2 that is physisorbed on the surface, which can be removed by vacuum only, is five times less than the chemisorbed co2 [22]. the enthalpy and chemical potential of adsorption become less negative as the adsorption proceeds at higher temperatures due to weaker binding at the surface, and this leads to increased entropy. the explained that the co2 adsorption on mmen-mg2(dobpdc) falls into three regions: strong chemisorption, intermediate chemisorption, and weak physisorption. most of the co2 is taken by the chemisorption, in which most of the active sites being occupied. understanding the physical chemistry associated with the adsorption of co2 on these materials helps in enhancing these materials for industrial processes. although increased adsorption towards co2 was observed in mmen-mg2(dobpdc) in the presence of water, further study for m2(dobpdc) stability and adsorption need to be further investigated under humid atmospheric conditions [24] [25]. 2. conclusions: direct air capture is an interesting technology that has attracted significant attention in recent years and perhaps has to be taken more into consideration. the major appeal of this technology is its flexibility of location and the significantly low content of contaminants such as nox and sox that it needs to deal with. removing co2 using this technology is mostly held back today, however, by the expected cost of regeneration (i.e., high operating costs) and its inherent low yield (i.e., high capital costs) authors /al-qadisiyah journal for engineering sciences 12 (2019) 000–000 5 compared to traditional approaches. the cost of dac can be greatly reduced by using solid adsorbents [20] that offer significantly higher working capacities around the partial operating pressures of carbon dioxide in the air with small swings of pressure or temperature. the functionalization of solid adsorbents with amines in recent efforts has shown to be correctly pointing in this direction [10][4]. mofs impregnated with amines have shown great working capacities to adsorb co2 under dilute concentrations due to the cooperative insertion of co2 into the active metal sites causing s-shaped isotherms [4]. these materials also showed high reversibility by only having small temperature changes applied [4][10][17], while there has been much research effort towards improving the adsorption working capacity of mofs, which makes dac more of an attractive approach, there is still much to be done for the commercial competitiveness of those materials to show promise. future efforts must be more significantly focused on the achievement of cheaper manufacturing and improved stability. references [1] c.r. murdock, s.a. didas, c.w. jones, direct capture of co2 from ambient air, (2016). doi:10.1021/acs.chemrev.6b00173. 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[10] l.a. darunte, a.d. oetomo, k.s. walton, d.s. sholl, c.w. jones, direct air capture of co2 using amine functionalized mil-101(cr), 101 (2016) 4–11. doi:10.1021/acssuschemeng.6b01692. [11] c. chen, m. tavoni, direct air capture: a model-based assessment, (n.d.) 1–13. [12] k.s. lackner, s. brennan, m. matter, a. park, a. wright, the urgency of the development of co2 capture from ambient air, (2012) 1–7. doi:10.1073/pnas.1108765109. [13] k. sumida, d.l. rogow, j.a. mason, t.m. mcdonald, e.d. bloch, z.r. herm, t. bae, r. long, carbon dioxide capture in metal-organic frameworks carbon dioxide capture in metal à organic frameworks, (2015). doi:10.1021/cr2003272. [14] h. jasuja, y. huang, k.s. walton, adjusting the stability of metal-organic frameworks under humid conditions by ligand functionalization, (2012). [15] d.m.d. alessandro, b. smit, j.r. long, carbon dioxide capture carbon dioxide capture: prospects for new materials angewandte, (2010) 6058– 6082. doi:10.1002/anie.201000431. [16] m.b.t.c.m. cr, c. link, m.b.t.c.m. cr, c.r. wade, m. dinc, accessed investigation of the synthesis, activation, and isosteric heats of co2 adsorption of the isostructural series of metal-organic frameworks, (2017). doi:10.1039/b000000x. [17] t.m. mcdonald, w.r. lee, j.a. mason, b.m. wiers, c.s. hong, r. long, capture of carbon dioxide from air and flue gas in the alkylamine appended metal-organic framework mmen-mg2 (dobpdc ), 2 (2012). [18] w. liang, r. babarao, d.m.d. alessandro, microwave-assisted solvothermal synthesis and optical properties of tagged mil-140a metal − organic frameworks, (2013) 12878–12880. [19] j. chen, l.s. loo, k. wang, an ideal absorbed solution theory (iast) study of adsorption equilibria of binary mixtures of methane and ethane on a templated carbon, (2011) 1209–1212. [20] w. lu, j.p. sculley, d. yuan, r. krishna, h. zhou, carbon dioxide capture from air using amine-grafted porous polymer networks, (2013). [21] shabbani, hind jihad kadhim.(2017). determination and validation of high-pressure equilibrium adsorption isotherms via a volumetric system. (master's thesis). retrieved from https://scholarcommons.sc.edu/etd/4310 [22] v.a. online, d. wu, t.m. mcdonald, z. quan, s. v ushakov, p. zhang, materials chemistry a, (2015) 4248–4254. doi:10.1039/c4ta06496h. [23] s. v. ushakov, a. navrotsky, direct measurements of water adsorption enthalpy on hafnia and zirconia, appl. phys. lett. 87 (2005) 1–3. doi:10.1063/1.2108113. [24] j.a. mason, t.m. mcdonald, t. bae, j.e. bachman, k. sumida, j.j. dutton, s.s. kaye, r. long, application of a high-throughput analyzer in evaluating solid adsorbents for post-combustion carbon capture via multicomponent adsorption of co2, n2, and h2o, (2015). doi:10.1021/jacs.5b00838. [25] j. wang, m. wang, w. li, w. qiao, d. long, l. ling, application of polyethylenimine-impregnated solid adsorbents for direct capture of lowconcentration co2, 61 (2015). doi:10.1002/aic. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 420 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. effect of polishing on the fatigue resistance and residual stresses for the shot peened of 7075-t6 aluminum alloy assist. prof. ahmed naif ibrahim al-khazraji, university of technology, department of mechanical engineering. email: dr_ahmed53@yahoo.com eng. rasool mahdi awwan al-shabbani, university of technology, department of mechanical engineering. email: eng.rma91@yahoo.com received on 5 april 2017 accepted on 31 october 2017 published on 30 december 2017 doi: 10.30772/qjes.v10i4.491 abstract: aluminum alloy (7075-t6) is widely used in various industries in parts of aircraft, automobiles and other mechanical applications. it is known that the process of the shot peening leads to an increase in the value of residual stresses, which prolong the fatigue life. however, during surface peening of various metals, including aluminum alloy (7075t6) used in this work, these surfaces become rough where the places to concentrate the stresses, which will fail when exposed to different dynamic stresses. this paper presents an study on the effect of polishing (the roughness surface induced from shot peening process) on endurance limit and residual stresses result by shot peening. in this paper was used three values of surface roughness (1.5, 3, and 5) μm. the obtained results show that the maximum increasing in endurance limit was (53%) at low roughness compared with as received and increasing value roughly to (27%) compared with alloy after shot peening. . the residual stresses gradually increased (-222.735, -229.602, -250.900) mpa when the roughness surfaces decreased (5, 3, 1.5) μm respectively. keywords: polishing shot peening, residual stress, endurance limit, aluminum alloy (7075-t6). introduction aluminum alloys are an attractive class of materials because of their high specific static strength. usually, high static mechanical properties are induced in aluminum alloys by dispersion hardening through solution and ageing heat treatments [1, 2]. al alloys are frequently subjected to surface treatments in order to improve their plain and notch fatigue strength. among them, shot peening is one of the most widely used. this process consists of bombarding the component with small spherical shots of a hard material at a relatively high velocity. the multiple indentation of the ductile target surface increases its surface roughness and causes localized plastic deformation, which in turn results in work-hardening and introduction of a inplane compressive residual stress field in the surface layers [3,4]. components are regularly subjected to dynamic loads, which make them prone to fatigue failure. it is a well-known fact that almost all fatigue cracks form at the surface due to a variety of surface stress mailto:dr_ahmed53@yahoo.com mailto:eng.rma91@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 421 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. concentration failures. evidently, the control of surface initiation and growth of cracks is an effective means of enhancing the fatigue endurance of metallic components [5,6]. the results showed that obtained from the positive influence of the shot peening treatment on the fatigue properties as caused by hardened surface layer and compressive residual stresses delayed the initiation of fatigue cracks. shot peening treatment nearly doubled the cycles to failure at the higher applied stresses when compared to the untreated specimens [7]. aggressive shot peening tends to increase the surface roughness which can be detrimental to fatigue performance. the higher roughness creates short crack growth and reduce the fatigue life [8]. the fatigue life reduction factor (lrf) due to the aggressive shot peening was established and empirical relations were proposed to describe the behavior of lrf, roughness and fatigue life [9]. in this paper, the effect of surface polishing of the shot peening aluminum alloy (7075-t6) on the residual stresses and endurance limit is studied. because the shot peening surfaces of the aluminum alloy lead to the creation of roughness on the surfaces, which generates the concentration of stresses in some rough places, when exposed to dynamic loads will descend the ages of the functionality of these pieces because of the concentration of stresses. the rough surfaces were polished with three different degrees (5, 3 , 1.5μm), and the study of the change of the residual stresses on the surfaces after being polished, as well as the effect of this polishing on the change endurance limit for the selected alloy. 1. experimental work 1.1. material the materials used in this study is 7075-t6 aluminum alloys, low-specific weight and high strength to weight ratio and also high electrical and thermal conductance. this alloy is widely used in industry and in particular in aircraft structure and pressure vessels. the main alloying element in the 7xxx series is zn, while mg and cu are also introduced in order to improve the properties [10]. the chemical analysis of this alloy is in table (1) and the mechanical properties is presented in table (2) . table 1: chemical composition of 7075-t6 aluminum alloy. table 2: mechanical properties percentage composition si % fe % cu % mn % mg % zn % cr % ti % al % nominal [asm] [11] 0.4 max. 0.5 max. 1.2 2 0.3 2.12.9 5.1 6.1 0.180.28 0.2 balance measured 0.01 67 0.05 5 1.69 0.01 1 2.59 5.68 0.21 7 0.02 8 balance modulus of elasticity gpa hardness, vickers elongation at break % tensile yield strength mpa ultimate tensile strength mpa 74 152 10.1 483 521 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 422 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1.2. preparation of samples two types of specimens were prepared in this study; one for tensile test were prepared according to standards of astm e8, see figure 1. and the other is for the fatigue tests were prepared according to machine specifications [12], see figure 2. specimens manufacturing process was done by using a programmable cnc milling (c-tek) machine. figure 1: specimen geometry and dimensions for tensile test (all dimensions in mm) according to astm e8. figure 2: specimen geometry and dimensions for fatigue test (all dimensions in mm) according to machine specifications [9]. 1.3. shot peening the shot peening is accomplished by machine of sintokogio ltd, model stb-ob. in this machine, the motor rotates an impeller which bombard the shots towards the specimens at 1435 r.p.m motor rotational speed with one jet of shots at an average speed of 70 m/s. the material of the shooting balls is a low carbon steel with average diameter of 1.2 mm and coverage of 80-100 %. the peening machine consist of rotary cylinder with inside diameter of 590 mm and depth of 740 mm in which the specimens is placed. both tensile and fatigue specimens were subjected to shot peening. the time used for shot peening was (12min), this optimum time for aa 7075-t6 taking from reference [13], see figure 3. 100 32 30 6 30 r=6 25 10 1.32 100 10 4 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 423 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 3: tensile test specimen and fatigue test specimen after shot peened process. 1.4. polishing of specimens after shot peening process, specimens were prepared using the silicon carbide papers as (200,400, 800) to make three values of surface roughness, they are (5, 3, 1.5) μm respectively, using surface roughness testing machine type diavite dh-7. 1.5. tensile test the type of used tensile test machine was microcomputer controlled electronic universal testing machine tinius olsen h50kt. tensile tests were done before and after shot peening and for all stages of the polishing process. three specimens were tested for each case and taking the average value to satisfy an additional accuracy. 1.6. fatigue test the type of fatigue testing machine used in this work was hi-tech alternating bending fatigue (hsm20) with constant amplitude loading. a series of tests are commenced by acting a specimen to the stress cycling and the number of cycles to failure is counted. this procedure is repeated on other specimens at progressively decreasing stress amplitudes. as a result, the surfaces of the specimens are under tension and compression stresses when the specimen fluctuated. all the tests done at constant stress amplitude loading with 𝑅 = −1. the obtained data were plotted as stress s versus the logarithm of the number n of cycles to failure for each of the specimens. 2. results and discussion 2.1. tensile test results to obtain the mechanical properties, the tensile tests of the chosen material 7075-t6 aluminum alloys were performed to obtain the values of the ultimate tensile stress 𝜎𝑢, yield stress 𝜎𝑦 and elongation 𝐸%. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 424 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table (3) , lists the tensile values for the as received, after shot peening and polishing proses compared to the american society for testing and materials specifications (astm) at room temperature. the results of tensile tests showed that the ultimate tensile strength has a small increasing according to shot peening effect, but the amount of increasing depends on the compressive residual stress and variation with it. the maximum percentage changes of ultimate tensile is (7.485%) for aluminum alloy 7075t6 polishing for surface roughness (ra=1.5 μm). table 3: tensile tests results alloy type condition (mpa) (mpa) 7075-t6 standard 573 504 7075-t6 received 521 483 7075-t6 shot peening 533 491 7075-t6 ra=5 μm 545 496 7075-t6 ra=3 μm 554 501 7075-t6 ra=1.5 μm 560 506 2.2. s-n curve the s-n curves were obtained from the fatigue tests for all specimens as received, shot peening and polishing process after shot peening at surface roughness ra (5, 3, 1.5) μm, see figures (4,5) . from these data, the fatigue life estimation equations were obtained, the endurance limit at = cycles. figure 4: s-n curve for 7075-t6 aluminum alloy. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 425 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: semi log s-n curve for 7075-t6 aluminum alloy. from the results of the fatigue test of polishing process (for three stages), it can be observed that the value of the endurance limit of this process is higher than the value of endurance limit of shot peening, that’s due to the effect of the compressive residual stresses and roughness surface was decreased. the equations and fatigue strength which describes this curve are given in table (4). table 4: s-n curved equations for 7075-t6 t6 aluminum alloy. condition surface roughness ra(μm) s-n curve equation (mpa) increase in % received ra=0.19 =4237.4 -0.243 147.6 shot peening ra=6.093 =6934.6 -0.265 178.25 20.765 polishing process ra=5 = 7553.9 -0.268 186.28 26.206 ra=3 =7548.6 -0.262 202.24 37.02 ra=1.5 =6046 -0.238 225.67 52.892 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 426 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. -ra curve of laboratory specimens are presented in figure (6) . the experimental equations of surface roughness and endurance limit can be shown in table (4) for polishing process. the relation between surface roughness and endurance limit can be described by the formula (1)... = 543.52 (1) from figure (6) , the endurance limit is increasing due to decreased of surface roughness in addition to the presence of residual stresses, the maximum value of endurance limit is (52.892%) at less surface roughness (ra=1.5 μm). figure 6: -ra curve for polishing process. 2.3. residual stress the x-ray diffraction (xrd) measurements of the residual stress on the surface were taken by using machine type lab6000, figure (7) , with stress analysis adapter before and after shot peening and polishing process of specimens, the result are shown in the table (5). -ra curve of laboratory specimens are presented in figure (8) . the experimental equations of surface roughness and residual stress can be shown in table (5) for polishing process. the relation between surface roughness and residual stress can be described by the formula (2)… = 543.52 (mpa) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 427 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. (a) (b) figure 7: ax-ray diffraction (xrd) machine type lab-6000 & bxrd machine with specialized stress analysis system x-ray source x-ray detector stress analysis system al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 428 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. = (2) from figure (8), the residual stresses gradually increasing when the roughness surfaces decreasing, this shows that the residual stresses are generated by shot peening process at, or just below the surface layer for a certain depth and usually it is higher that on the surface. table 5: experimental residual stresses results for 7075-t6 aluminum alloy. figure 8: -ra curve for polishing process condition surface roughness ra(μm) (mpa) received ra=0.19 -3.477 shot peening ra=6.093 -263.527 polishing process ra=5 -222.735 ra=3 -229.602 ra=1.5 -250.900 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 429 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. conclusions the main conclusions drawn from this paper are : 1. after polishing (for less surface roughness ra=1.5 μm ), the maximum enhancement percentage (53%) of the endurance limit was obtained compared with as received material. 2. while the max. improvement carried out of (27%) in the endurance limit at same roughness (ra=1.5 μm) compared with shot peened specimen. 3. the residual stresses were increased as surface roughness decreased in polishing process. 4. a small improvement obtained in some mechanical properties such as ultimate tensile stress (𝜎𝑢) which was (7.485%) compared with as received at high smoothing (ra =1.5 μm). 5. it was obtained from this study two math. models to calculate the endurance limit & surface roughness and the 2 nd model to calculate the residual stresses & surface roughness such as : = 543.52 & = references 1. m. benedetti, v. fontanari, m. bandini and d. taylor, “mu`ltiaxial 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“modification of fretting fatigue behavior of al7075– t6 alloy by the application of titanium coating using ibed technique and shot peening” ,tribology international, vol.42, pp.121– 129, 2009. 12. n. p. roberts and nigel r. hart, "alternating bending fatigue machine (hsm20), instruction manual", hi-tech ltd. uk. , 2001. 13. ahmed n. al-khazraji and thamer a. al-taie, "the effect of shot peening on the notch sensitivity factor and neuber characteristic length for 7075-t6 aluminum alloy",journal of engineering and development, vol.19, no.4, issn 18137822, 2015. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٧٩ ��� 2� ��� ���� �� �&* %� ��� ��$�� �� �� � ������ ��� ���*+� ���� �#�*1 ���#� �6-!�� : !" �"�#��� ���%� ��"�� ��2 �����( �#(%0��� *9 �� ����#3% *�% �#� (�� ��'*�%���� �6�* �� � ��#��� �(�� ��(��� ���� �� ��'*�%���� b�c�d� � ������� . �#� ���(�� ���%'� �0(%� ��0 '��� ���'�%�� � 7%0' @�.� �����(�� �� ���(heat sinks) 7�0�� k 0�� � ���(�� ��'� ��( 0�� �(�0��� �����" ��c� ���%0% l�( ��� �����(�� ��*����� s�97'�� c�%�% * -!���7�� �(��� 4�, . ����(�� ����%'� ����� ��0(* -j'1c��� k 0�� >���(�� b� d� 4�1 �9'1c�� ��� ��#3% �0�� �% � ��(��� �� %* j'�1c* ���*��� ��� %0� j'�1c� �9'1c� x* 0 � �(� . �%��%�� 8 4��, ��h*%�� ��% (dissipated) x* 0�� ���( !" ���1 */ ��� ���� ���*��� ��� %0� j'�1c� �9'1c��� x* 0�� � >���(�� �� %* j'�1c� �9'1c��� . j'�1c� �9'1c��� x* 0�� ���( !" �����(�� ��*����� *�% l�( �� ��� ���� �� %* (31%)���*��� ��� %0� j'�1c� �9'1c��� x* 0�� � . ��9'1c� x* �0 � �(�� ��(��� ���(�� ���%'� ����� ��0(� ������% �� ��� 4�, �h*%�� �% @�.� �� %* j'�1c* ���*��� ��� %0� j'�1c� . ���(��� ���(�� ���%'� ����� ��0(� ������%�� �� ����� �'���� �% � ��'�� l�( ���'�� �� ?�� % @�'/ ��* ����0 l*(� 5� ���*��� ��� %0� j'�1c� �9'1c� x* 0 � �(� 3 7�� ��0'(0.12%). ����c�� 0#���� :��$#� f��� ���� f�&* %� g��� f�*# %� ��� h0#�*�����i ����j� study of fins shapes' effect on natural thermal convection waleed mohammad abid engineering college anbar university ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٠ abstract: in many electric circuit boards thermally induced buoyancy effects are not always sufficient to adequately cool high density electronic packages found in modern circuit boards. instances thermal enhancement techniques, such as heat sinks, must be used to increase the effective surface area for heat transfer so lower the thermal resistance between sources and sink. both vertical rectangular and pin finned surfaces were studied to show the shape effect and natural convection heat transfer coefficient. the thermal dissipated from vertical rectangular finned surfaces greater than pins finned surfaces. the overall thermal resistance of the pins finned surfaces greater (31%) compared with vertical rectangular finned surfaces. an empirical equation was predicted to calculate average natural convection heat transfer coefficient from vertical rectangular and pin fins. the results show an excellent convince with the literature review where the overall error was about (0.12%). %���� ��c#� : %��� �*��� %��� �*��� as ��( 0�� �(�0���(m2) gr j*�%��� 1 b �%9'1c �� �"�0���(m) n j'�1c�� 1 cnet �0��'��� ���d� ��#���'� * k 0�� �(�0� 4�1 �%�� ���# �78 4�, k 0 �. nu ��0' 1 d � �9'1c�� � � �� %*�(m) p �9'1c�� �(�(m) f ����� ���1 pr �% '��� 1 h ��(��� ���(�� ���%'� ����� � ��(w/m2ºc) q ���%'��� ���(�� ����(w) h �9'1c�� �* (m) ra >i�� 1 k �9'1c�� ��� �����(�� ���h*���(w/mºc) ra* �* ��� >i�� 1) 0(���( kf ���(�� ���h*��� 56���� ��(w/mºc) t ���(�� ��� m �9'1c�� b�9� ����0( !" � 7%0� ���# t �6�#%ا� $� (m) g !+�d� ����%��(m2/s) w �6�#%�2 ا�� 6hض ا��#(m) ��*��!�9 %���� ���&�� k������9 %���� %��� �*��� %��� �*��� η �9'1c�� b�9� conv. ��(�� β �%�� ����� !��(�8 (1/k) rad. )���a� ν ��%��'���� ��*c��(m2/s) total !���� σ 9�%0 ���#y ��c%�*� s ��( 0�� ρ �"�#���(kg/m3) ∞ �(��� ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨١ ���.�� o�i%�� k 0 �(�0� ��c� ��'� �9�%7� ?� @�'/ �0� >8 � ��(��� ���(�� ���%'� � �� �0(%� 56���� 5� .k 0 ��c ��� �%�� x* 0 �"�+b� 56���� 5� o�i%�� (extended surface) k 0��� 4��, �����(�� �� ���� 41 � �� �'*�� 7�0��(heat sinks) . j'�1c��� %���� x* 0�� 41 %(fins) *��%* ���*����� j'�1c�� �#� �9�%7� )�*'8* ����3�)���* �� ((vertical fins) ����"d� j'�1c�� -(horizontal fins) �� %*�� j'�1c�� *8 (pins) . �� ������ ��0 '��� ����� %�� � ��#��� !" %���� x* 0�� ��'�% � 7%0% �9�%7��� ��'*�%���� * ��6������� c��d� * j���%��* ���%�� ���*&'� -�����(��[1]. (�� ��(��� ���(�� ���%'� ���� !" ����0�� l*(��� * ��0�� �� ����' ?�� � j�'1c� k 0 � � ����1)������% ( x* 0��� ��.�' ��*�h�� � l�( b!��� s�� ��� *�% �� ��� * ���&'�� �*�(�� *�� ��� �� * �7c�� * ������%0�� �� ��� �(* �9'1c���[2] . �� k 0 � �(�� ��(��� ���(�� ���%'� ����� ��0(� �� 7%0��� ������%�� �� ����� �/8 � !�*�� l(���� ����8 �h*% !%�� �� ����� !/ j'1c�(elenbass) [3] : 75.0 ra 35 * * e1ra 24 1 nu           −−−−====         −−−− (1) l�((ra*) �* ��� >i�� 1 ) 0(���modified.( �#(���� � �(van de pol and tiemey) [4] ������% ��i1 >i��� ���� ��g% ����� ��0' �� � *����� ���*����� j'�1c�� �(�� ��(��� ���%��) * ���� ( �������% ���'��� 4�1 '%0� ��*%0� �(�9h� ����0(welling and wooldridge) [5] e ��� �+ (0.6< ra<100) . �#(���� e �(jones and smith) [6] � �1*��� 4�1 ��#��� �0�� ��� %0���� ���"�� j'�1c�� ���.���� $�%�� ?��%� ���" �90�� * 4�1�� *(' ���*� . >i�� * ( �+ ������% ��i1 4�, �#(���� �h*% (2×10 2 < ra<6×10 5 ) �%��(�� i�� >i�� ��� ��g% ����� ��0' ��� �� )�90d� * 4�1d� .( �#(���� ?� (garg and velusamy) [7] �� �*�( ��7�%��� ���(boundary layer) o*��0i� ��� ��� o�08 4�1 (blasius equation)>����%�� ���.*�' !" =* c� ��� ��&%'� ��g�� �� (�� *���� ��0(� . =.���'�� �%�7��� *8 �(�� ��(��� ���%�� �"*%� �0�� ��#����� . *#(����� � 7%�0�(culham et. al) [8] =.*��' (meta) �� � 3� e �� �+ ���*��� �*h� �9'1c� x* 0 � �(�� ��(��� ���(�� ���%'� s�1 ���( >i�� ��� � 50�*(103< ra<1010) <6�%'�� �'�� l�( ��'*�%���� �6�* �� >���(�� @*�0�� ���(% s�g� x�%���� =.*�'�� �� �� ?"�*%(meta) l(���� ������� <6�%'�� * (karagiozis)0' �'�� l�( �� 3 7�� �� <6�%'��(9%) . *#(���� �h*% @�.�(yovanovichet et. al) [9] ���(�� ���%'� ����� ��0(� ��i1 4�, ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٢ �.7c -����� ����( j'�1c� �9'1c� �'�* 0� � @�.�* !�*��� ���� j'1c� k 0 � �(�� ��(��� " ��&'� ����%�� ��% ��g�� ������ �� '� ���%1��(developing) * �� ������7�� ? �'��� ��7�%��� ��� �� �� '� j'1c��� k 0�� . ��0�(* -j�'1c��� k 0�� >���(�� b� d� 4�1 �9'1c�� ��� ��#3% �0�� 4�, !��(�� l(��� j �� �� %* j'�1c* ���*��� ��� %0� j'�1c� �9'1c� x* 0 � �(�� ��(��� ���(�� ���%'� �����. :*#�� �b ������� %#+�� ����� ��(��� ���(�� ���%'� c��� �� 7%0� �%�� !" ��� ���� )l( l��( ������� ����%7��� ����%�� ���� � c����� *�%� > *�1 5 ���� �� %0� e��� '%0� ���( 4�1 4�1 ��#� > � ( k 0>*%0� x* 0* j'�1c� j'1c� ��'�* 0� $� %* * j'�1c -���(%� ���*��� ��� %0� ��% ��� ���� ����(,* b�*��� e��� !" �%��#%� ���#%�� 5��0 �i� � 0�*� -=��7�� � e����� �'�� !" �� j'1c� k 0 �h�'1 4��1 >*%(� !6����� �70%) heater( ����( 5� �����( �70%�� + �9���) 6�c��( ����(�� $�� 4�, �*h*�� '�" (100ºc) o0(%��� �*���%* ��� ��� �*c%�� 5 �� !��*( 4�, ���(�� $�� *�/ '1 �����(85ºc) . k 0�� j'1c��� �i7 $% /��� ��� ���%7�� �(% ����� ����� �(%" $������� ; �� � j�9� e����� $���* !" . � �� =*�7�� '1* �*7 �� '1 b�*��� ���( $�� o��� e����� � ���( $�� @�.�* x* 0�� �9'1c��� j'�1c� � ��� %0����*�� $� %** >���(�� =* c��� o�� �i7 � )thermocouple( 5�� �h�%� */* o���� b����� !��� (digital thermometer) ����� . 4�1 c����� >*%(� @�.� � �0�� �� ��* ��%��% !" ��(%�� � � �&'��8 *c��� ;� � j'1c��� k 0���* ���%7�� �(% o�������%���� !����� .��� k 0�j'1c� �h%���� �� � �0�� $�.g%�8 $�h* @�0 ?�� 1 . !" !6������� ���%�� � h�� �%� ��0�6��� ��� ��� �*c%�� �� �� ����'� ��h%��� ��.g%�� $�h* @�0 ?�� 1 ��%7��� � �0�� . ������� ����%�� b���8 $��� "���� ��m ������ :�#��� ���.� ��: �*d� �0���: ����8���1*� ��9'1c� $(�9�h �� 7%0�� $���1 ����% )finned plate) (100mm×110mm ( ���*��� ��� %0� j'�1c� (vertical fins) $'��� ��� !" ��� ���� )3($�0% �%�# l�( ) e ( ���� j'�1c , !�*����9h�� 4�( $��*������ ��� �*��'��d� �� �1*'h�� (k=201w/mºc) ����a�� (l=100mm, ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٣ h=66.5mm, t=1.5mm) . ��� ���� c����� ;� ��8 ���g% �%*)1-18 w( �� ���� ���( $�� o��� �% j'1c���)ts (!���7�� b�*��� ���( $�� * )t∞ ( c����� ;� ��8 ��� � 5��� '1. !%d�� )���a�� ���%'��� ���(�� $��� ��0( �% [2]: )tts(fasq 44 .rad ∞∞∞∞−−−−==== σσσσ (2) l�( : f :����%�� �� ����� � �0(�* j'1c��� k 0�� ����� ���1 �#�� [9]: )l2b(h c2 f net ++++ ==== (3) l�( : cnet. :0�� �(�0� 4�1 �%�� ���# k �0��'��� ���d� ��#���'�*�7c 4�, k 0 � . >i�� ��� ��0( ��� @�.�)ra ( !%d��[1]: pr )( pr 2 3 ν β bttsg grra b ∞− == (4) l�() :b ( �%9'1c �� �*h(��� �"�0��� */)b=10mm.( �* ��� >i�� ��� ��0( �%�) ra* modify rayliegh number (!%i� �9'1c��� x* 0�� ���( !"[9]:       ==== ∗∗∗∗ l b rara b (5) l�(: )b/l(�9'1c�� �* 4�, �%9'1c �� �*h(��� �"�0��� �� ��0'�� */).b/l=0.1.( ��0( �%�!�� ��� j'1c��� k 0�� ��0' ���: )tts(ask qb nu f .conv b ∞∞∞∞−−−− ==== (6) l�(: as :�� $(�0�j'1c��� k 0�� ��( 0��) as=2lh(n-1).( n: 1 j'�1c��) n=9 (j'1c��� k 0��. ( !" �#f� ����� .73% �9'1c�� b�9� �0�(%* j�'1c��� k 0�� ��(��� ���(�� ���%'� ����� ��0 !%i� [1]: ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٤ )1 l t ( t h b h k k nu2 )1 l t ( t h b h k k nu2tanh f b f b fin ++++ ++++ ====ηηηη (7) bfinb nunu ηηηη==== ∗∗∗∗ (8) l�( :nub*�9'1c�� b�9� ��#3% .7� �� ��0' ��� . .conv.radtotal qqq ++++==== (9) !'�#�� �0���: $(�9�h �� 7%0�� $���1 ����% 1 ����8 ��'�* �0� ��� %* j'��1c� ��9'1c�)pins plat ( )100mm×110mm ( ��� ����� !" $'��� ���)v (l�( ��1 ���0 �%�# )p\ ( ��'�* �0� ��� %* �9'1c ���a�� �*�'��d� � �1*'h�(d=13 mm, h=67 mm) j��7%� ���� ��%�� (staggered) ���g% �% !�� ��� c����� ;� ��8)118 w (��*%0��� $(�9h�8 ���( $�� ��g%% !��%���* .�0( �%� ���( $�� � �9'1c��� $(�9h�8)ts ( !���� ���( $�� o���� �� 7%0��)digital thermometer ( ����( $��� * �(���)t∞ .( ��0( �%� c����� � ���* �(��� ���( $�� * �9'1c��� $(�9h�8 ���( $�� ;b��� �� !����: )tts(fasq 44 .rad ∞∞∞∞−−−−==== σσσσ (10) >i�� ��� ��0( �%� @�.�)ra( pr d)tts(g pr.gr 2 3 ra d νννν ββββ ∞∞∞∞−−−− ======== (11) l�( : 8 ��6��g�� ���(�� $�� '1 b�*��� n�*7 �.7)tf =(ts+t∞)/2 ( �% '��� ��� @�.�*)pr.( ��0' ��� ��0( �%�)nud(!%m�� : f .conv d k)tts(as dq nu ∞∞∞∞−−−− ==== (12) l�(: as :!%i� �0(%* j'1c��� k 0�� ��( 0�� �(�0��� :(((( )))) dln)dn(wlas 2 2 ππππππππ ++++−−−−==== � � ��*c��* (� �* ��. �� %*�� �9'1c�� 8 s�" 4�1 !%i� �0(% �9'1c�� b�9� ����'�[1]. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٥ (((( )))) mh mhtanh ====ηηηη (13) l�(: k k d nu4 m f 2 d ==== (14) .conv.radtotal qqq ++++==== (15) nc#�*� ���#*� ���� )5( ��� %0�� j'�1c* �� %* j'�1c� �9'1c��� k6�9h�� ���(�� ���� !" ?�9�� ��g% ��� c����� � ��� 5� ���*���. i18 ����� � &(i' l�( ; ��9'1c��� �(�9h��� ���(�� ���� !" ?�9�� 8 �� %* j'�1c� �9'1c��� �(�9h�� ���(�� ���� !" ?�9�� � ��� *�� ���*��� ��� %0� j'�1c� . ��0�� * l�( �9'1c��� �( 0�� i�� �����(�� ��*����� 4�, *��: th .conv r has 1 q t ======== ∆∆∆∆ (16) �� ��� ��� ���*����� ��� %0��� j'�1c�� ���( !" �����(�� ��*����� *�%(31%) ������(�� ���*����� �� � �( 0�� i� !" ��*�0%� ��( 0�� �(�0��� *�% �� '1 �� %*�� j'�1c�� �9'1c�� . � &(i' @�.� ���6� )5( ���(�� ���� ��c� � c� ���(�� ���� !" ?�9�� 8 ) c����� � ��� ( �9'1c���� �( 0�� i� !" . �9'1c��� �( 0�� �� ���(�� ���� !" ?�" ��� �� l�((0.7ºc) �/�� ��� c��� � � '1 (1w) ( 0�� �� ���(�� ���� !" ?�" ����* �9'1c��� �(6.2ºc) �/�� �� c��� � � '1 (18w). ���� )7( ����� � &(i' -�� %* j'�1c� �9'1c� �(�9h� ������� >i�� 1* ��0' 1 �� ��i��� ��� >i�� 1 ��c� � c� ��0' 1 8 . ���(��� ���(�� ���%'� ����� ��0(� ������% �� ��� 4�, �h*%�� �% � �(�� <��'���� �� 7%0�� �� %* j'�1c� j'1c� k 0statistics v5.5) (��i��� ��� �� l�(: 75.0 dd ra008.0nu ==== (17) *(r2= 95%) !/ ������� ����� * �� ����� �� 3 7�� ��0'* �� ����� (0.18%) . ��8 ���� )�( ��i��� ��� ���*��� ��� %0� j'�1c� �9'1c� �(�9h� ������� >i�� 1* ��0' 1 �� . 1 8 ����� � &(i' l�( >i�� 1 ��c� � c� ��0' . � �(�� ��(��� ���(�� ���%'� ����� ��0(� ������% �� ��� 4�, �h*%�� �% j'�1c� j'1c� k 0��*��� ��� %0�� <��'���� �� 7%0�� statistics v5.5) (��i��� ��� �� l�(: (((( )))) 75.0bb ra045.0nu ∗∗∗∗==== (18) *(r2=98%) !/ ������� �����* �� ����� �� 3 7�� ��0'* �� ����� (0.08%) ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٦ ���� ) ( ���*��� ��� %0� j'�1c� �(�9h� >i�� 1* ��0' 1 �� ��i��� ��� . ���� ����� �� ���� ������ $g�h� ��* ������� ����� � ����, �h*%�� �% !%�� ������%�� �� �����* ������� ����� �� �'���� l(����(elenbass) [3]����%�� : 75.0 ra 3.37 * * e1ra 24 1 nu           −−−−====         −−−− (19) !/ ;i18 �� ����� * ������� ����� �� 3 7�� ��0' �'�� l�((0.31%) ��% !�%�� ��� ����� �� 3 7�� ��0'* !" ����, �h*%�� ���� )�( !/ ;i18 �� ����� * (0.12%). ��#-�� : 1. cengel y. a. 'heat transfer a practical approach' mcgraw-hill, int. 2001. 2. lienhard iv j. h. and lienhard v j. h. 'a heat transfer textbook' third ed. cambridge, ma: phlogiston press, 2006. 3. elenbass w. 'heat dissipation of parallel plates by free convection' physical, vol. 9, no.1,1942. 4. van de pol d. w. and tiemey j. k. ' free convection nusselt number for vertical u-shaped chamels' j. of heat transfer, vol. 95, 1973. 5. welling j. r. and wooldridge c. b. ' free convection heat transfer coefficients from rectangular vertical fins' j. of heat transfer, vol. 87, 1965. 6. jones c. d. and smith l.f. 'optimum arrangement of rectangular fins on horizontal surfaces for free convection heat transfer' j. of heat transfer, vol. 92, 1970. 7. garg v. k. and velusamy k. ' heat transfer characteristics for a plate fin ' j. of heat transfer, vol. 108, 1986. 8. culham j. r. , yovanovich m. m. and lee s. 'thermal modelling of isothermal cuboids and rectangular heat sinks cooled by natural convection' ieee transaction on components, packaging, and manufacturing technology-part a, vol. 18, 1995. 9. yovanovich m. m., teertstra p., and culham j. r. ' natural convection modelling of heat transfer sinks using web-based tools. www.electronics-coollingcom/html/2000-sep-a4.html,2004. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٧ �����)p (�(�� ��(��� ���(�� ���%'� c���. �����)u (���*��� ��� %0� j'�1c� j'1c��� k 0�� ���8. ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٨ 0 5 10 15 20 25 30 35 0 3 6 9 12 15 18 21 (w) ?%+��� ?��.� (t s -t ∞ ) ة ار � ا �� در ق �� ����� �*# %� ���&�����#� ������� �*# %� ���& �����)� ((�� ���� !" ?�9�� ��g% ��� c����� � ��� 5� �9'1c��� �(�9h�� ���. �����)v (�� %* j'�1c� j'1c��� k 0�� ���8. d w l h ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٨٩ �����)5 (�� %* j'�1c� �(�9h� >i�� 1* ��0' 1 �� ��i��� ���. �����)^ (���*��� ��� %0� j'�1c� �(�9h� >i�� 1* ��0' 1 �� ��i��� ���. 0 0.5 1 1.5 2 2.5 3 0 50 100 150 200 250 ra n u nu= 0.045 ra^0.75 0 1 2 3 4 5 6 1000 2000 3000 4000 5000 6000 7000 ra n u nu=0.008 ra^0.75 ٢٠٠٩ ���٢د ا٢ ���� ا���د � �����م ا���� � ا����� ٩٠ �����)\ (0� j'�1c� �(�9h� >i�� 1* ��0' 1 �� ��i��� �'�������*��� ��� %. 0 1 2 3 4 0 50 100 150 200 250 300 ra n u elenabass ���#�� ��#�� ���� �#���1 ���#�� template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 643 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. excess molar volumes, surface tensions, viscocity deviation and ftir spectroscopy of 1-butanol-ethyl acetate binary system mixture mustafa j. nuhma, chemical engineering department, engineering college, university of al-qadisiyah, al-qadisiyah, iraq. e-mail: mustafa.alhamadani@qu.edu.iq received on 12 november 2017 accepted on 28 december 2017 published on 15 march 2018 doi: 10.30772/qjes.v10i4.511 abstract: the physical properties (viscosity, surface tension and density) were computed in laboratory using different laboratory equipment for binary and pure system at (p=1 atm and t=25c). at mole fraction 0.5, the excess volume was found to be positive value while the deviation in viscosity and surface tension was found as negative values at the same mole fraction. experimental excess properties were compared using redlich-kister equation and showed acceptable standard deviation. the inter molecular interaction of the 1-butanol and ethyl acetate found to be negligible and the vulnerability of the hydrogen bonds according to the ftir spectra to a mixture of 1-butanol and ethyl acetate is consistent with the positive values of excess volume. overlying the values of surface tension and the deviation in viscosity was found as negative values for all mole fractions studied. keywords: 1-butanol, density, ethyl acetate, viscosity, ftir analysis, excess molar volume, surface tension and molecular interaction. introduction many of industrial processes require a large amount of information related to the physical and chemical properties of different types of fluids. physical and chemical properties, for example, excess properties and intermolecular interactions are very important factors that affect the molecular structure and lead to the non-ideal deviation in the transport phenomena (fluid flow, the mass and heat transfer) [1-5]. several studies have been carried out to study the excess thermodynamic properties of different types of non-aqueous liquids mixture [6-21]. the importance of thermodynamic excess properties is not only useful for the design and study of transport phenomena, but also for obtaining the appropriate data, which is the basis for the development of new predictive equations and linking them with special relationships. on the other hand, the practical data for the density of the binary liquid mixture was used to calculate the excess volume property related to the intermolecular interactions [22-24]. anwar discussed changes in the values of excess thermodynamic properties with the change in composition and the temperature and their impact on hydrogen bonds and their effect on the mixing process [25]. shekaari et al. used the excess properties in studying the polymer's effectiveness and demonstrated increased effectiveness by increasing the molar mass of polymer [26]. from above survey we conclude that 1-butanol and ethyl acetate are important solvents and have been used in many industrial processes and there is a need for thermodynamic process data which is the basis for theoretical and design purposes. the current study provides practical and al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 644 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. numerical data for the excess molar volume, the surface tension deviation and the viscosity deviation. the redlich-kister equation was used for correlation of the practical data. ftir analysis was obtained and checked for 1-butanol – ethyl acetate binary liquid mixture as well as to clarify the excess and the deviation property. 1. experimental 1.1. materials and method 1-butanol and ethyl acetate were obtained from the fisher scientific (united kingdom). the binary mixtures were prepared for the experiment using an electronic balance by cpa-225d, germany, and manufactured by sartorius. the measured weight accuracy was  0.01 mg. the density is measured using the densometer (anton bar, dsa5000m, austria). the calibration of the densometer was performed using degassed distilled water. ethanol had been used to clean the tube of the vibrator for the densometer. the surface tension properties of the pure and binary of 1-butanol and ethyl acetate are determined using a surface tension measuring device (ly-1068 tensometer, china) . the accuracy of this device is within range  0.0001. the capillary viscometer was used to determine the viscosity of the pure and the binary mixture of 1-butanol and ethyl acetate. the viscosity was calibrated using distilled water and ethanol. the accuracy of this device has been determined where it within a value of  0.028 m 2 .s-1. the ftir spectra of the 1-butanol and ethyl acetate liquid system are recorded using bruker, tensor ii, germany. the reading clarity of this device was within the 1 cm -1 for the spectrum range between 4000-400 cm -1 . 2. the results and discussion 2.1. the density and excess molar volume the densities of pure and mixture for 1-butanol and ethyl acetate have been measured in practically and have been tabulated in table (1) and table (2) . the measured density was obtained at 25c and at normal pressure. the excess molar volume was calculated according to the following equation and the values were set in table (2). where (vm) were calculated from the practical values of the mixture density according to equation (2). where: vm: mixture molar volume. vi: 1-butanol or ethyl acetate volume. mw: molecular weight of the 1-butanol or ethyl acetate. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 645 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ρ: density of the mixture volume. xi: mole fraction of the 1-butanol. figure (1) shows the change in molar volume with the molar fraction of 1-butanol. the nonlinear increase was observed in excess molar volume with increased molar fraction. the non-ideal behavior of the excess molar volume can be due to the interactions and the intermolecular in the binary system of the liquid mix of 1-butanol and ethyl acetate, which have been explained by other researches [27]. the positive value of the excess molar volume was obtained for all fractions and the highest value of the molar volume was obtained at the value of the molar fraction 0.3. table 1: experimental data of surface tension (σ), density (ρ) and viscosity () for pure 1-butanol and ethyl acetate at 25 o c.    m.wt substance no. 2.544 cp 24.93 dyn/cm 0.810 g/cm 3 74.123 g/mol 1-butanol 1 0.423 cp 24 dyn/cm 0.9 g/cm 3 88.106 g/mol ethyl acetate 2 table 2: deviation of the surface tension (), surface tension (σ), density of the mixture (ρm), excess of molar volume (v e ), viscosity (mix) and deviation of the viscosity () for the 1-butanol and ethyl acetate mixture at standard conditions.  mix   v e m x2 x1 -0.034 0.601 -0.29 23.803 0.034 0.819 0.9 0.1 -0.075 0.772 -0.54 23.646 0.061 0.882 0.8 0.2 -0.089 0.970 -0.68 23.599 0.079 0.873 0.7 0.3 -0.077 1.194 -0.65 23.722 0.074 0.864 0.6 0.4 -0.064 1.419 -0.53 23.935 0.053 0.856 0.5 0.5 -0.052 1.643 -0.37 24.188 0.028 0.847 0.4 0.6 -0.036 1.871 -0.29 24.361 0.019 0.838 0.3 0.7 -0.02 2.099 -0.15 24.594 0.011 0.828 0.2 0.8 -0.008 2.323 -.006 24.777 0.004 0.819 0.1 0.9 0 2.544 0 24.93 0 0.81 0 1 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 646 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0 0.2 0.4 0.6 0.8 1 1.2 e x c e s s m o la r v o lu m e 1-butanol mole fraction figure 1: excess molar volume as a function of 1-butanol mole fraction for the 1-butanol-ethyl acetate binary mixture. from our results related to the excess molar volume, we can put a mathematical equation showing the change in the values of the excess molar volume with the change of the molar fraction values of this binary mixture: v e = 0.0932 x 4  0.8283 x 3  1.2984 x 2  0.5699 x  0.0038 the equation that was concluded above agreement with the results of study carried out jiménez et al. [27]. 2.2. surface tension deviation the values of the deviation in surface tension were calculated from the surface tension practical data and according to the following equation [27]: the change in surface tension deviation values with the molar fraction of 1-butanol is illustrated in figure (2) and is summarized in table (2) . the negative behavior in the surface tension deviation values of all the specified molar fraction values is clearly shown. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 647 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 2: surface tension deviation as a function of 1-butanol mole fraction for the 1-butanol-ethyl acetate binary mixture. from our results related to the surface tension deviation, we can put a mathematical equation showing the change in the values of the surface tension deviation with the change of the molar fraction values of this binary mixture:  = 1.0897 x 4  2.3221 x 3  7.6295 x 2  4.2358 x  0.00184 the equation that was concluded above agreement with the results of study carried out jiménez et al. [27] 2.3. viscosity deviation the viscosity deviation was computed from the practical data of the viscosity of the pure and the binary mix liquid at the different mole fractions using the following equation [27]: the calculated values for the deviation in viscosity were set in table (2) and were illustrated in figure(3). all these values for the deviation of the viscosity are negative values. the lowest value of the deviation in viscosity was at 0.3 molar fraction of 1-butanol. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 648 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 3: viscosity deviation as a function of 1-butanol mole fraction for the 1-butanol-ethyl acetate binary mixture. from our results related to the viscosity deviation, we can put a mathematical equation showing the change in the values of the viscosity deviation with the change of the molar fraction values of this binary mixture:  = 0.1369 x 4  0.844 x 3  1.3054 x 2  0.603 x  0.0038 the equation that was concluded above agreement with the results of study carried out άlvarez et al. [28] 2.4. redlich-kister correlation the values of excess molar volume, surface tension deviation and viscosity deviation were corrected relative to the redlich-kister equation as the following [29]: where: x1, x2: are the mole fraction of 1-butanol and ethyl acetate respectively. ai: are the coefficients of the redlich-kister equation and tabulated in the table (3). the standard deviation (sd) of the binary system was computed using equation (6) and the results were tabulated in table (3) [27]. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 649 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. m, n: are the experimental samples and the constraints number respectively. the experimental results showed a reasonable deviation from theoretical values as shown in table(3) . table 3: the coefficients of redlich–kister equation in the case of correlation the excess molar volume (v e ), surface tension deviation () and viscosity deviation for the samples of 1-butanol-ethylacetate mixture at (t=25 o c and p=1 atm). function temperature, o c a0 a1 a2 a3 a4 sd v e 25 o c -0.0038 0.5699 -1.2984 0.8283 -0.0932 0.0004  25 o c 0.00184 -4.2358 7.6295 -2.3221 -1.0897 0.00003  25 o c 0.0038 -0.603 1.3054 -0.844 0.1369 0.0006 2.5. ftir and intermolecular interaction ftir spectroscopy analysis is an effective and very important analysis of the properties of polar chemicals and can be used to regulate functional group and molecular interaction [30]. in the figure (4) below, the ftir analysis of the 1-butanol-ethyl acetate mixture was developed. the ftir spectra for a mixture of 1-butanol – ethyl acetate at different mole fractions showed a very important behavior for hydrogen bonds and demonstrated the non-ideal behavior and deviation in the thermodynamic properties as explained in the previous sections. as seen in the ftir, the amplitude of the hydrogen top indicates the effect of the intermolecular interaction and the sharpness due to obvious the intermolecular interaction as well. for the pure 1-butanol, the spectra shows a broad o-h stretch at 3350 cm -1 while the most important peak in the pure ethyl acetate showed a strong c=o peak at 1750 cm -1 . while, for the 1-butanol – ethyl acetate mixture, the increase in molar fraction caused a weak displacement in the place of the c=o peak to a maximum wave number. the effect of hydrogen bonding is weak for the current mixture and has led to weakness intermolecular interaction between 1-butanol and ethyl acetate. the result of the ftir spectrum is consistent with the result of the excess volume and the conclusions were clarified by other researchers [31]. the physical effect mainly involves non qualitative physical correlations, breaking down the hydrogen bonds in the molecules themselves, weaker dipole – dipole interaction, and interstitial accommodation due to different the molar volumes and the free volumes between undesirable molecules, producing in positive al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 650 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. excess molar volume values. the chemical and the structural-geometrical effects was created due to the specific interactions such as forming of hydrogen bonds, charge – transfer (donor– acceptor) complexes, strong dipole–dipole interactions, differences in the size, shape of the component molecules, and making a negative volume excess values [32 35]. the concentration based thermophysical properties denotes that the deviation from the ideal behavior of the mixtures and to be provided an indication of the interactions between unlike components in the mixtures. figure 4: ftir spectra of 1-butanol, ethyl acetate and binary mixture of 0.5-0.5 1-butanol-ethylacetate at temperature=25 o c and pressure=1 atm. conclusions 1-the practical result of excess volume, surface tension deviation and viscosity deviation showed a nonideal behavior with changing in molar fraction. 2. the correction of excess properties using the redlich-kister equation showed an acceptable deviation from the practical results. ethyl acetate 1-butanol 0.5 1butanolethyl acetate al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 651 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3. the result of the ftir showed compatibility with the result of excess volume and demonstrated internal hydrogen bonds between 1-butanol and ethyl acetate was weak for the mixture and can be concluded that there is a weakness in the place of the upper c=o peak of the highest wave number. 4. determination of excess thermodynamic properties and refractive index of other mixing systems not previously addressed. references 1. naessems rm, clará ra, marigliano ac. , density, viscosity, excess molar volume and viscosity deviation for [chloroform (1)+ methanol (3)] 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313.15 k. fluid phase equilibria. 2001 aug 1;186(1):207-34. article al-qadisiyah journal for engineering sciences 12 (2019) 178–183 available online at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author e-mail address: nasser21272@gmail.com (abdulnasser m. abbas) https://doi.org/10.30772/qjes.v12i3.615 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. numerical investigation on the influence of web opening on the structural behaviour of rc deep beams abdulnasser mohammed abbas a* a civil engineering department, engineering college, basrah university, basrah, iraq a r t i c l e i n f o article history: received 24 august 2019 received in revised form 29 september 2019 accepted 10 october 2019 keywords: deep beams web openings special reinforcements abaqus a b s t r a c t nowadays, the deep beams become utilized more in a considerable number of structures. it is necessary sometimes to introduce a hole within the web of the beam as a pipe or a duct for many purposes such as water supply, sewage, electricity, air conditioning, and computer network. in this study, a deep beam sample taken from a past experimental study is numerically analysed using a three-dimensional finite element model. abaqus tools are used to simulate the whole fe models. the dimensions of the considered deep beam are 820x400x180 mm, with two openings of a diameter 90 mm located at 200 mm from both of the ends. the proposed model and the experimental work have reasonably agreed with a difference of 2 % in mid-span deflection. furthermore, special reinforcements of 12 mm bar diameter are offered to the original fe model around the holes in two types, z-shape and circular, to improve the structural behaviour of the deep beam and to minimize the crack concentrations in these zones. the gained results show that the additional reinforcement minimizes the mid-span deflection of the deep beam. as compared with the original proposed fe model, the z-shape decreases the deflection by 44.9 % while the lowering in the defection of the circular shape is 9.4 %. moreover, the concentration of stresses and cracks that gained from using the z-shape reinforcement model found to be lower than those induced in the circular reinforcement model. © 2019 hosting by university of al-qadisiyah. all rights reserved. 1. introduction the essential definition of the deep beams in the aci 31814 code [1], can be summarized as a member made from reinforced concrete and loaded on a single front, while supports lie on the other front. in the meantime, the clear span to the overall depth ratio must equal or not exceed four, also, it is necessary to mention that the concentrated loads must be applied within 2h distance from the support face. while the hypothesis of bernoulli for (slender) beams which states that, plane sections continue plane is not applied to the deep beams, because the strain distribution on the beam is nonlinear, and this led the deep beam to behave as a restricted arch. deep beams are utilized vastly in constructions like floor diaphragms, foundation pile caps, shear walls, and wall footings [2]. moreover, during the last few decades, deep beams are used extensively in high rise buildings [3]. the failure mode of deep beams depending on the geometry of these members, and it is utterly dominated by shear failure instead of flexural. therefore, the shear strength factor becomes highly crucial in the concrete design of deep beams [4]. in modern structures, it is necessary to install numerous http://qu.edu.iq/ mailto:nasser21272@gmail.com https://doi.org/10.30772/qjes.v12i3.615 file:///d:/00%20mechanical%20department/00%20مجلة%20القادسية/استمارات%20ونماذج/qjes/qijes%20ok%202.docx abdulnasser mohammed abbas /al-qadisiyah journal for engineering sciences 12 (2019) 178–183 179 ducts and pipes for air conditioning, water supply, electricity, sewage, and computer network. these ducts or pipes are usually laying beneath the beam soffit, and due to aesthetical causes, they covered by a pseudo roof. on the other hand, there is another configuration that could be made to make these pipes and ducts pass-throughout slots created in the beams. this configuration is considered as a compact and economical design of deep beams [4]. indeed; these cross slots (pipes and ducts) within the web of the beam will minimize the gross stiffness of such beams; and then, may cause high deformations due to resulting service loads that produced from the internal forces redistribution which lead to minimizing the beam ultimate strength to a critical stage [5]. the existence of a hole in the deep beams produces a geometric cut-out in these members, and stresses will be distributed nonlinearly through-out the beam depth [6]. unfortunately, there are no specifications included in the ac1318m-11 [7] to the deep beam web openings. therefore, there is a great need for a uniform, accurate and safe design methodology for this issue. furthermore, a special rebar configuration should be provided adjacent to or around to the hole, with an adequate amount to avoid possible beam failure and to keep crack under control [8]. yang et al. [9] studied the concrete strength diversity influence on extreme strength of shear, and they found that it was considerably lower in deep beams that having holes rather than deep beams without holes. moreover, the concrete strut compressive strength for a deep beam with holes rise at a minimum rate when the concrete strength increased gradually. yang et al. [10], conducted a study on the deep reinforced concrete beams that have openings. in this investigation, the quantity of sloping rebar and the opening breadth was considered as the prime variables. a proposed to the influence of the inclined rebar quantity and the hole size was done on the beam's structural behaviour. the shear strength and width of the diagonal crack for the tested beams was noticed to be considerably dependent on the active inclined factor of the test specimen reinforcement, which is varied from 0 to 0.318. when this operator rise, the width of the diagonally inclined crack and its rate will reduce, then, the strength of shear for the tested beams will improve. maaddawy and sherif [11] investigated the possibility of utilizing the exterior bind of the composite cfrp (carbon fibre reinforced polymer) sheets just as a reinforcement manner to enhance the efficiency of deep reinforced concrete beams with holes. the parameters that considered are the existence of the cfrp plates, location and size of the opening. the deep reinforced concrete beams structural response with the opening existence mainly dependent on the interruption grade to the path of the natural load. the cfrp plates which are bonded externally around the holes increase the enhancement of the deep beam shear strength. the gained strength due to the utilizing of the cfrp plates is within 35–73%. in 2012, campione and mianfo [12] found that the load of the first crack and failure mode influenced by the existence and location of the hole. for instance, if the hole located at the mid-span, the beam response does not influence, while if the hole is set inside the shear span, the capacity of load-carrying will minimize about 18-30 %. an investigation was conducted by alsaeq [13] on the influence of the location and shape of the opening on the structural behaviour of the deep reinforced concrete beam, while the size of opening remains unchanged. finite element analysis was carried out by using ansys12.1. the ultimate deep beam strength with the existence of a web opening determined by the mentioned numerical method appearing adequate compatibility with the experimental outcomes. the gained results indicate that the opening position has a great influence on the strength of the member more than its shape. moreover, the placement of the hole adjacent to the upper deep beam corners may enhance the strength two times. on the other hand, when a narrow opening with a rectangular shape used horizontally along the sides, it may save more than 40 % of the deep beam structural strength. an experimental investigation was done by sheelu and afia, [14], on the deep reinforced concrete beams with the existence of a circular hole. eight deep beams with 820 mm length, 400 mm depth and 180 mm width having a single opening, double openings and a control specimen were tested by applying a 50 ton point load. the considered parameters are; the size and position of the opening, provided web reinforcement, the presence, and percentage of the cfrp sheets. the whole tested beams are failed by compression diagonal shear. in general, the cracks are initiated as flexural cracks, and they are absent when the load is equal to or below 45 % from the ultimate load. a two opening beam holds about 79 % of the ultimate load, while in the case of a beam with a single central opening, the capacity of the load was unchanged. beams that reinforced by fiber exhibited no change in the load-carrying capacity, however, when a comparison is made with specimens that having no fiber, the existence of such fiber reduces the crack width. ragheed et al. [15] investigate eight concrete deep beams made from reactive powder, which analyzed nonlinearly using ansys v.15 tool. the outcomes obtained theoretically from the simulated models were compared with the results that gained experimentally. the parametric study consists of three parts that were done by varying the opening size, opening position, and configuration systems of cfrp. the comparison demonstrates that the results obtained from the ansys are identical, to some extent, with the experimental outcomes, and the variation of the ultimate load is approximately below 7.5 %. ammar and maha [16] presented an experimental and theoretical study on the rc deep beam to investigate the overall shear behaviour. a concrete hybrid strength technique was employed, in which normal (ordinary) strength was used in the tension region, while high strength was utilized in the compression region. nine samples of deep beams were made and loaded by two concentrated loads. two groups of deep beams were used to investigate many parameters, such as the influence of the existence of the web reinforcement, the deflection, the pattern of cracks, the cracking load, the frailer modes, and the ductility. moreover, a compression made between both of the experimental and analytical outcomes, which revile an adequate agreement to the response of the load-deflection relationship. the optimum variation rate in the starting crack and the ultimate loads was found to be 13 % and 9.6 %, respectively. in the present work, fe analysis will be made using the abaqus tool to simulate rc deep beam with two openings, the taken sample of the deep beam is mentioned above as an experimental work done by sheelu and afia [14]. a comparison will conduct between the results obtained by the fe simulation and the experimental outcomes to examine the compatibility of the proposed fe model with the experimental one. moreover, a special reinforcement around the two holes is provided to enhance the structural behaviour of the deep beam. 2. beams modelling the proposed numerical model depends on an experimental work conducted by sheelu and afia, [14]. the considered dimensions of the deep beam were 820 mm (length), 400 mm (depth) and 180 (width), with two 90 mm diameter circular openings at 200 mm from both sides of the beam. the deep beam is subjected to a single point load as shown in fig. 1. the modulus of elasticity for concrete determined according to aci 318m [1], which is defined as ec = 4700 √f c′ (mpa). brief details for the steel reinforcement and concrete compressive strength are shown in table 1. 180 abdulnasser mohammed abbas /al-qadisiyah journal for engineering sciences 12 (2019) 178–183 figure 1. experimental settings [14] table 1. details of the deep beam [14] 3. simulation of numerical (fe) model to imitate the deep reinforced concrete beam numerically in abaqus software, the elements of the member (concrete and rebar) should be modelled accurately in a three-dimensional environment. first of all, the units of the input data for the proposed model must set to be harmonious (there is no compact system for units in abaqus) [17]. the deep beam is loaded by a single concentrated load at mid-span [14], therefore, steel plates are used in the model to dispense stresses on a wider region. these plates are placed over the mid-span of the deep beam as a loading plate, and at the bottom as supports at both sides. the supports of the deep beam are considered as a roller and pin in the proposed model. then, stress 3-d elements are used to the concrete part, where suitable integration rules are supplied for such elements depending on the experimental response of the sample. therefore, brick linear elements of 8node (c3d8r) are utilized to imitate the concrete and the loading and supports steel plates. plastic damage parameters have used to reflect the behaviour of the concrete [3]. the parameters used for concrete damage plasticity are exhibited in table 2. table 2. parameters of damage plasticity for concrete the rebar is assumed to be able for transmission only an axial force, and the steel uniaxial stress-strain relationship is idealized using a bilinear curve, which is used to demonstrate the elastic-plastic behaviour together with the strain hardening. moreover, to calibrate the plastic-damage pattern, the stress-strain relationship has presented as discreet stages, to the strength of compression and tension, for various concrete resistance that obtained from the uniaxial tests [18]. the concrete uniaxial compressive behaviour in abaqus is defined as stress versus inelastic strain relation [3] as shown in fig. 2. figure 2. uniaxial compressive stress-strain relation for concrete [3] to consider the concrete degraded response, two uniaxial damage variables, compressive (dc) and tensile (dt), are set in the cdp (concrete damaged plasticity) model [3], as shown in fig. 3. a b figure 3. concrete damage behaviours: a: compressive damage, b: tensile damage [3] finally, the concrete has meshed with different elements size; however, the size of 20 mm has demonstrated suitable outcomes, and when a smaller size of the element has used, the differences in results are not significant, see fig. 4. the mechanical properties for concrete and steel are exhibited in table 3. figure 4. the mesh utilized to imitate the deep beam table 3. the mechanical properties for concrete and steel while the reinforcements and stirrups are modelled using (t3d2) 3-d linear truss element with 2-node, see fig. 5. these elements are selected because the rebar has no high stiffness bending. furthermore, it is assumed that perfect bond is held between the steel rebar and the concrete throughout the whole analysis. then, an embedded constraint choice was picked to ensure that there is a full bond between the concrete and steel [19]. corresponding to the approach of von mises, a bilinear pattern is taken to abdulnasser mohammed abbas /al-qadisiyah journal for engineering sciences 12 (2019) 178–183 181 simulate the behaviour of steel, rodríguez et al., 2012 [20]. therefore, the material will behave linearly (elastic) until the stress reaches the yield point, then, after this stage, it will fully plasticize, as the constitutive pattern does not appear any stiffness. figure 5. representation of rebar and stirrups 4. results discussion: 4.1 model validation the performance of the proposed numerical model has examined by comparing the outcomes that earn from the fe model with those obtained experimentally by sheelu and afia in 2016 [14]. fig. 6. shows the mid-span deflection for both the experimental and numerical works. a remarkable difference is found in the mid-span deflection between the experimental and the numerical results in the early stages of loading. however, as the load increased, the differences are gradually decreased to be approximately 2 % which is considered reasonable to some extent. the varying in the differences between the current work and the experimental one may come from the manner that used in applying the loads, the position of both load and supports, and finally, the assumptions that used in the construction of the numerical model. therefore, the proposed model can be used to enhance the efficiency of the deep beam by adding a special reinforcement in the region around the openings. figure 6. deep beam mid-span deflection 4.2 special reinforcements around the holes: as previously mentioned, the fe model has suitably simulated the experimental sample taken from a past study [14]. however, it is beneficial to carry out more analysis to enhance the efficiency of the region adjacent to the openings. actually; this is done via special reinforcements around the hole, as shown in fig. 7. two types of special reinforcement with a bar diameter of 12 mm have used, the first consists of three legs, two are parallel with the stirrups and tied with them well, while the middle leg has inclined in 45o normal to the direction of cracks that may induce by the shear forces, see fig. 7.a. however, the second type of reinforcement is circular and located around the hole, as shown in fig. 7. b. a b figure 7. special reinforcement around the openings two shapes of a special reinforcement are used to examine their influence on the structural behaviour of the considered deep beam. comparisons have also made between the special reinforcement models with the original numerical one. fig. 8. shows the mid-span deflection for the proposed numerical three models, the original with no-special reinforcement (nil), the z-shape and the last is circular, both of the special reinforcements are made from bars of 12 mm diameter. indeed, slight differences are observed in the mid-span deflection, for the whole three models, at a load equal or below 100 kn. however, as the load increased from 100 kn up to 450 kn, the variation in deflection as compared between the (nil) model and both the circular model and the z-shape one will be lowered to 9.4 % and 44.9 % respectively, see table 4. in the meantime, when compared with the original model, the ultimate load will increase for the circular model and the z-model to 6.3 % and 10.7 % respectively, also see table 4. this indicates that the z-shape reinforcement enhances the deep beam structural behaviour better than the circular shape. figure 8. mid-span deflection for the fe three models table 4. mid-span and ultimate load comparison with nil special reinforcement model fig. 9. shows the variation profile for the vertical deflection and the deformation of the deep beam for the analysed three models. it can be seen, as mentioned above, that the differences appear clearly between the original model and the z-shape model. 182 abdulnasser mohammed abbas /al-qadisiyah journal for engineering sciences 12 (2019) 178–183 a b c figure 9. y-direction displacements: (a) nil; (b) cr12mm; (c) z12 mm fig. 10. shows the von-mises stresses for the analysed three deep beam models. these figures exhibited significant lowering in the von-mises concentrations for the model that improved by adding a z-shape special reinforcement around the holes. moreover; the minimum value of these stress is 2.42 x 10-01 for the deep beams that reinforced with circular rebar, while the lower value in the beam that strengthens with z-shape is 1.05 x 10-02. this indicates that improvement using z-shape will induce lower stress. a b c figure 10 von mises stress: (a) nil; (b) cr12mm; (c) z12 mm fig. 11. presented the crack profile for the three analysed models. the crack path is diagonally moving from the loading zone to the supports region. furthermore, the crack concentrations have lowered due to the employment of the special reinforcement around the holes. it can be seen, that the z-shape model gives lower concentrations of the crack around the openings than the circular reinforcement model. a b c figure 11 crack pattern: (a) nil; (b) cr12mm; (c) z12 mm 5. conclusions: depending on the outcomes that determined from the numerically simulated three models, the following conclusions may be stated: 1. differences are found, in the mid-span deflection, between the experimental results and the original fe model at the early stage of loading, however, as the load increases the variation will be minimized gradually to be approximately 2 %. this leads to a reasonable agreement, to some extent, between the proposed fe model and the experimental one. 2. the z-shape reinforcement will lower the deflection by 44.9 % as compared with the original model, while the circular reinforcement will lower the deflection by 9.4 %. 3. for the circular model, the ultimate load rises by 6.3 %, while for the z-model the ultimate load increases by 10.7 %. 4. the von-mises stresses have been decreased by using special reinforcements. for a model that reinforced with a z-shape around the holes, the minimum stress value is 1.05 x 10-02, while for the deep beams with a circular rebar the lower value is 2.42x10-01, which indicates that using of z-shape reinforcement will induce lower stress. 5. the crack concentrations have minimized due to the employment of the special reinforcement around the holes. in the meantime, it has recorded that the using of z-shape reinforcement will induce lower crack concentrations around the holes. abdulnasser mohammed abbas /al-qadisiyah journal for engineering sciences 12 (2019) 178–183 183 references [1] aci 318-14, “building code requirements for structural concrete”, american concrete institute, 2014. [2] mohamed, a.r., shoukry, m.s. and saeed, j.m., “prediction of the behavior of rc deep beams with web openings using the finite element method”, alexandria engineering journal, 53, 2014, 329-339. [3] aydin demir, hakan ozturk, gokhan dok, “3d numerical modeling of rc deep beam behavior by nonlinear finite element analysis”, disaster science and engineering, 2016, p. 13-18, 2(1). [4] nishitha nair, kavitha p. e, “effect of openings in deep beams using strut and tie model method”, international journal of technical research and applications, volume 3, issue 5, september-october, 2015, pp. 59-62. [5] jin-seop lee and sang-sik kim, “shear behavior of reinforced concrete deep beams with web openings”, journal of the korea concrete institute, vol. 13, no. 6, 2001, pp. 619-628. [6] guan, h. and doh, j. h., “development of strut-and-tie model in deep beams with web openings”, journal of advances in structural engineering, vol. 10, no. 6, 2007, pp. 697-711. [7] aci committee 318, “building code requirements for structural concrete (318-11) and commentary (318-11)”, american concrete ins., detroit, 2011. [8] mansur ma, tan kh, lee sl., “collapse loads of rc beams with large openings”, asce str. eng. journal, vol.110, no. 11, 1984, pp. 2602–10. [9] k yanga, h eunb and h chungc, “the influence of web openings on the structural behavior of reinforced highstrength concrete deep beams” engineering structures, 2006, pp 1825–1834. [10] k yang, h chung, and a f ashour, “influence of inclined web reinforcement on reinforced concrete deep beams with openings”, aci structural journal, vol 104, 2007. [11] t e maaddawy and s sherif, “frp composites for shear strengthening of reinforced concrete deep beams with openings”, composite structures, vol 89, 2009, pp 60–69. [12] g campione and g minafò, “behaviour of concrete deep beams with openings and low shear span-to-depth ratio”, engineering structures, vol 41, 2012, pp 294–306. [13] h m alsaeq, “effects of opening shape and location on the structural strength of r.c. deep beams with openings”, international journal of civil, environmental, structural, construction and architectural engineering, vol 7, 2013. [14] er. sheelu mariam punnoose, er. afia s. hameed, “experimental study of strengthening of rc deep beam with web opening”, international journal of innovative research in technology, volume 3 issue 4, september 2016. [15] ragheed fatehi makki, ali talib jassem and hayder abd al-latef jassem, “non-linear analysis of reactive powder concrete (rpc) deep beams with openings strengthened by cfrp”, al-qadisiyah journal for engineering sciences, vol. 11, no. 2, 2018, pp 176196. [16] ammar yaser ali and maha ghazi zghair, “experimental investigation and nonlinear analysis of hybrid reinforced concrete deep beams”, alqadisiyah journal for engineering sciences, vol. 8, no. 2, 2015, pp 99119. [17] abaqus, “abaqus/standard version 6.10 user's manuals: volume i-iii”, hibbitt, karlsson, and sorenson, inc., pawtucket, ri, 2010. [18] rodríguez g., bonilla j. y hernández j. j., “numerical modeling of reinforced concrete continuous deep beams”, revista ingeniería de construcción vol 31 no. 3 diciembre de, 2016. [19] ihsan a. s. al-shaarbaf, ahmed s. ali, abdulkhalik j. abdulridha, “experimental and numerical investigation of high strength reinforced concrete deep beams with web openings under repeated loading”, alnahrain journal for engineering sciences (njes) vol.20 no.2, 2017, pp. 311-325. [20] rodríguez g., bonilla j. y hernández j. j., “aplicación de la simulación numérica al estudio del comportamiento de vigas de gran peralto de hormigón armado”, revista ingeniería civil, 167, 2012, 101–116. al-qadisiyah journal for engineering sciences 13 (2020) 268–273 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: duaanaabdzaid@gamil.com ( duaa n. abd zaid ) https://doi.org/10.30772/qjes.v13i4.680 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. heat transfer enhancement by turbulence generator inside heat receiver duaa n. abd zaida*, dhafer a. hamzaa auniversity of al-qadisiyah, department of mechanical engineering, ad-diwaniyah, iraq. a r t i c l e i n f o article history: received 6 august 2020 received in revised form 15 october 2020 accepted 20 november 2020 keywords: heat exchanger twisted tape pressure drop a b s t r a c t tubular heat exchanger (thex), that has been in numerous engineering applications, represents an apparatus that makes heat to be exchanged between two fluids having different changing in temperatures and kept separated by means of a solid wall. in order to enhance the efficiency of the thex, the rate of heat transfer at the tube side should be improved. inserting a twisted tape inside the heat exchanger’s tube is one of the passive techniques that has been widely used to improve the heat transfer especially in air conditioning and cooling, processes of power recovery, processes for food and dairy, and plants for chemical processing. the heat exchanger enhancement is achieved by means of using a twisted tape inserted with twisting ratios (tr) equal to 3.2, 4.4, and 5.5, independently. the influences of 2-d parameters such as nusselt number and frictional coefficient on the thex’s effectiveness were investigated. the aim of the study is inserting a twisted tape inside the testing pipe to produced turbulent flow and, therefore, creating large turbulence rate inside the pipe that plays an significant role in improving the transferred heat and increasing the drop in the pressure. in this work, the inserted tape has a width and length equal to 21.5 mm and 1000 mm, respectively. the inner and outer diameters of the used pipes were 23 mm and 22 mm, respectively. the tested sectional length of the thex was equal to 2000 mm. reynolds number was changed from 500 to 7000. results obtained from using twisted inserting tapes with varying tr were compared with result from plain tubes. these results were displayed in the contours show the distribution of the temperature and the trajectory of the flow trajectory by axial velocity for testing the low values of reynolds number applicability in heat exchanger applications. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction enhancing heat transfer technique refers to the improvement of thermohydraulic performance of heat exchanger. these techniques have been used in many applications such as heat exchangers, thermal power plant, process industries, refrigerators, air conditioning, automobiles, radars for space vehicles etc... high-performance thermal systems are needed in many engineering applications and, therefore, different methods are developed for improving the heat transfer (ht) [1] in the system. improved surface can offer a combinations or one of the following situations that are directly affect the increasing rate of heat transfer. unwelcome friction increase:  interruption of the boundary layers development and increasing the turbulence intensity.  increasing the area of heat transfer.  providing swirling and/or secondary flow. http://qu.edu.iq/ mailto:duaanaabdzaid@gamil.com https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ duaa n. abd zaid , dhafer a. hamza/al-qadisiyah journal for engineering sciences 13 (2020 ) 268–273 269 heat augmentation techniques are classified generally into the following categories: 1-active techniques: concerning the usage and design, these techniques considered as complex techniques because they require external source of the input power to produce the wanted flow and improve the htr (heat transfer rate). it usage still limited because of the requirement of source of the external power. 2-passive techniques: these types of techniques, no external source of input power is required. however, it depends on the system itself and finally leads to increasing the drop in the fluid’s pressure. normally, they utilize changes in geometry of the surface to the flow channel by including additional devices or inserts. therefore, promoting higher coefficients of heat transfer via altering or disturbing the behavior of existed flow. 3-compound techniques: if there are two or more of previous techniques that used together at once for obtaining the increment in rate at which the heat is transfer that is superior than that formed by each individually, they are referred to a compound enhancement technique. accordingly, most researchers preferred using the passive techniques over others owing to their applicability and simplicity to apply in many applications. in this research, the passive technique is under consideration. the passive technique is applied for producing the swirl flow and in turn disturbing the regions rich of the boundary layer close to the ht surface.[2] the passive technique can be achieved via installing the swirl turbulators/generators within the heating system. several researchers have studied the effect of different geometries on ht rate for several twisted tapes and how that enhance ht efficiency and affect the pressure drop.[3] few of them are as follows: manglik and bergles [4] formed a connection between the friction factor and the nusselt number suresh kumar et al. [5] reported thermo-hydraulic output due to using twisted tape inserts inside a large annulus with a hydraulic diameter. withada jedsdara tanchai, amnart boomloi [6] performed the numerical study on the influence of twisting ratios (tr) on the thermal improvement and ht of the flow structure in a circle with single twisted tape, the result show that ht in tube with twisted tape is more effective than that without twisted tape and reynold number decrease with increase twist ratio. patil et al.[7] achieved the experimental test of an inventive water-heating system with the aid of cfd, the result showed that high ht could be obtained at high twist tape rotating. yangium w. [8] studied numerically the optimized configuration of a regularly spaced short-length twisted tape inserted inside a circular tube to produce turbulence in the transferred heat in air utilizing cfd modeling for the reynolds number between 10000-20000. the results exhibited that the larger angle of twisting produced a higher value of ht along with a higher resistance in the flow. promvonge and eiamsa-ard [9] simulated the 3-d cfd modeling for several inserted tape shapes inside the tubes of the heat exchanger. three different types of different twisted tapes were used, namely plain, jagged v-cut, and v-cut along with utilizing two trs that equal to 2 and 4. friction factor and nu increased in inverse. manner with twist and width ratios at small depth ratio value the results shows that the ht rate in term of nusselt number, nu increase with the increase in depth ratio but decrease with increase in the width ratio of the tt. salman et al. [10] used the cfd technique for simulating the twisted tape inserted inside the tube having circular cross section with different locations and ratios. the hydraulic characteristics and the transferred heat increased when decreasing the tr. padalkar and yadav [11] simulated the b.cs of the exposed hot regions along with the configurations for generating swirl influence with trs. range. fazlay rubbi et al. [12] performed the numerical study to research ht performance increasing and flow behavior in a circular tube using twisted tape insert fitted with hes. the results show that for twisted tape insert with hemispherical extrude surface lead to increase in heat transfer rate above 69.4% compared to plain pipe due to effective vortex flow and best mixing caused by the tt insert. in this paper, a review of ht enhancement using twisted tape with different twist ratios. this paper is also giving performance criteria for different twist ratios of twisted tapes. 2. the numerical analysis and grid sensitivity in this study, cfd solid work software is used to investigate the turbulent swirl flow induced by twisted tape inserts. the solutions were completed with the multi physics commercial software solid work which can be used to model fluid flow, heat, and mass transfer for a big range of flow fields. cfd solvers (including solid work) help to discretize the flow field and solve the governing equations numerically. solid work is used to investigate fluid and ht problems by solving the governing equations over a particular region of interest. solid work is used to investigate fluid and ht problems by solving the governing equations over a particular region of interest. [13] viscous flow is administrated by the conservation of mass, energy, and momentum equations as follows: �⃑� ∙ �⃑� = 0 (1) 𝝆 𝑫�⃑⃑� 𝑫𝒕 = 𝝆�⃑⃑� + �⃑⃑� ∙ 𝝉𝒊𝒋́ − �⃑⃑� 𝒑 (2) 𝝉𝒊𝒋̀ = 𝝁 ( 𝝏𝒖𝒊 𝝏𝒙𝒋 + 𝝏𝒖𝒋 𝝏𝒙𝒊 ) + 𝜹𝒊𝒋 𝝀�⃑⃑� ∙ �⃑⃑� (3) 𝛒 𝐃𝐡 𝐃𝐭 = 𝐃𝐩 𝐃𝐭 + �⃑⃑� ∙ (𝐤�⃑⃑� 𝐓) + 𝛕𝐢𝐣̀ 𝛛𝐮𝐢 𝛛𝐱𝐣 (4) figure 1. grid sensitive. nomenclature f friction factor h heat transfer coefficient k thermal conductivity of the water nu nusselt number pr prandtl number pt the pitch re reynolds number sw swirl velocity tt twisted tape y twist ratio duaa n. abd zaid , dhafer a. hamza/al-qadisiyah journal for engineering sciences 13 (2020 ) 268–273 270 many grid sensitivity tests to ensure that the results are grid independent and 3350,000 cells number was selected for all the computations done in the present work. 2.1. problem and boundary conditions description cfd have used to examine effect of several ratios of the tape placed inside a long pipeof a half-length on the rate of ht. a specific pipe of 2m in length and 2.2 cm in diameter is used. in the current work, the wall of the pipe is assumed to be maintained at temperature of 310 k. while the temperature of the inlet water is maintained constant at 290 k. three values of the diameter/pitch ratio (tt) are set as 3.2, 4.4, and 5.5. each one of the trs has studied for reynolds number within the range of (500 to 7000). figure 2. twisted tape insert. y=3.2 y=4.4 y=5.5 plain pipe figure 3. plain pipe and pipe include twist tapes with three twist ratios. table 1: explain the pitch of three twist ratios and the number of twist for each ratio. twisted tape(tt) pitch(pt) pt/ dt number of twists tt1 70mm 3.2 15 tt2 90mm 4.4 11 tt3 125mm 5.5 7 3. theoretical calculation manglik and bergles have developed the theoretical calculation based on their well-accepted correlation of the twisted tape.[14], [15] they developed empirical relations for swirl flow as follows: sw= 𝐑𝐞𝐱/√𝐲 (5) (𝐟𝐑𝐞) = 𝟏𝟓.𝟕𝟔 𝐑𝐞 [ 𝛑+𝟐−𝟐𝛅/𝐝 𝛑−𝟒𝛅/𝐝 ] (𝟏 + 𝟏𝟎−𝟔𝐬𝐰𝟐.𝟓𝟓) 𝟏/𝟔 (6) for uniformly heated (uhf) tubes, the older hong and bergles [16]correlation given below: 𝑵𝒖 = 𝟓. 𝟏𝟕𝟐[𝟏 + 𝟓. 𝟒𝟖𝟒 × 𝟏𝟎−𝟑𝑷𝒓𝟎.𝟕(𝑹𝒆/𝒚)𝟏.𝟐𝟓]𝟏/𝟐 (7) for smooth tube: the theoretical friction factor 𝐟 = 𝟎. 𝟎𝟒𝟔 × 𝐑𝐞−𝟎.𝟐 (8) the theoretical nusslet number for smooth tube: 𝐍𝐮 = 𝟎. 𝟎𝟐𝟑 × 𝐑𝐞𝟎.𝟖 × 𝐏𝐫𝟏/𝟑 (9) 𝒉 = 𝟎.𝟎𝟐𝟑×𝒌 𝒅 × 𝑹𝒆𝟎.𝟖 × 𝑷𝒓𝟏/𝟑 (10) 4. results and discussions in this numerical and theoretical study, the results obtained of twisted tape effect on heat transfer cofficient and pressure drop and compare this result with the plain. figure 4. numerical solution of heat transfer coefficient vs. reynolds number for plain pipe, y=3.2, y=4.4 & y=5.5. figure 5. theoretical solution of heat transfer cofficient and reynold number. duaa n. abd zaid , dhafer a. hamza/al-qadisiyah journal for engineering sciences 13 (2020 ) 268–273 271 fig. 4 and fig. 5 show coefficient of heat transfer (h) variation as a function to the reynolds number for a smooth tube at different values of twist tape. one can notice that decreasing the twist ratio lead to develop swirls with higher degree. the presence of these swirls increases the flow turbulence, thereby, increase the coefficient of ht. in other words, ht rate increase as twist ratio decrease. the higher value of the coefficient of ht is noticed at the presence of the secondary flow, which develop the higher disturbance in the flow and the thermal boundary layer close the wall. that in turns, leads to increase the rate at which the heat is transferred. figure 6. theoretical solution of nusslet number for plain tube and the three twist ratios. figure 7. numerical solution of nusslet number for three twist ratios and plain pipe. figure 8. numerical solution of friction factor for three twist ratios and plain pipe. fig. 8 shows the variation of (f) with re number for plain pipe, and pipe with twist ratios (y=3.2, 4.4, 5.5). when twist ratios decreases, a high degree of vortex is created which leads to high friction cofficient. high friction factor is noted with twist ratio=3.2 due to increase in degree of swirl created by the inserted tapes. figure 9. comparison of the temperature distribution between plain pipe with that corresponding with a twist tape for y=3.2. duaa n. abd zaid , dhafer a. hamza/al-qadisiyah journal for engineering sciences 13 (2020 ) 268–273 272 figure 10. comparison of trajectory of flow (identified by z-velocity) between plain pipe with that corresponding with a twist tape for y=3.2. fig. 9 show the distribution of temperature between fluid flow and the wall for the ht. the results show that the temperature gradient decreases for both cases with increasing the reynolds number due to higher rate of the flow. the twist tape effect on the temperature distribution is obvious even on the first half of pipe. especially for low reynolds number, the variation temperature can be seen on all the length of the pipe. in the twist tape region, the ht increases as the swirl flow increases. the maximum temperature ranges (due to the presence of the twist tape) are 333 k and 316 k for laminar and turbulent flow, respectively. fig. 10 shows the demonstration of the motion of the swirl due to the twist tape with z velocity for tr=3.2, which is increasing with the number of reynolds. 5. validation test comparison between present numerical work and standard correlations (hong and bergles correlation [16]) for nusselt number for plain pipe in fig. 11 the results of present work reasonably agree within 8.3% error for nusselt number. figure 11. comparison between numerical and theoretical study. 6. conclusion the maximum rate ht is achieved by using twisted tape accompanied at 3.2 as a twist ratio. all twisted tape inserts would significantly improve the ht rate compared to the plain tube. the results from this numerical study can be concluded as follows:  as the twisted ratio decreases, the nu for twisted tape inserted increases at the specified twist ratios of 3.2, 4.4, and 5.5.  friction factor increases as the twist ratios decrease.  turbulent intensity considers a useful parameter for analyzing the swirling motion to increase ht.  the tape presence decreases the hydraulic diameter. this reduction increases the coefficient of ht even when the tape twist is zero.  the presence of the tape twist develops a tangential component of the velocity and this increases the flow speed specifically close to the wall. the main reasons of the increasing in the ht rate are the increasing in the shear stress at the wall and the secondary flow mixing.  the higher the wall thermal contact, the higher the rate of the ht from the tape. little hts from a loosely fitting tape is however expected.  by increasing the fluid turbulence in, twisted tape inserts duaa n. abd zaid , dhafer a. hamza/al-qadisiyah journal for engineering sciences 13 (2020 ) 268–273 273 increases the ht rate of the heat exchanger.  turbulent or swirl flow increases the thermal contact by boundary layer thickness reduction. references [1] chaware, p. and c. sewatkar, effects of tangential and radial velocity on the heat transfer for flow through pipe with twisted tape insertturbulent flow. international journal of heat and technology, 2017. 35(4): p. 811-820. [2] habeeb, l.j., f.a. saleh, and b.m. maajel, cfd modeling of laminar flow and heat transfer utilizing al2o3/water nanofluid in a finned-tube with twisted tape. fme transactions, 2019. 47(1): p. 89-100. [3] tusar, m., abdullah, i, majedul,y, prasad,s, bodius, cfd study of heat transfer enhancement and fluid flow characteristics of turbulent flow through tube with twisted tape inserts. energy procedia, 2019. 160: p. 715-722. [4] manglik, r.m. and a.e. bergles, heat transfer and pressure drop correlations for twisted-tape inserts in isothermal tubes: part i— laminar flows. 1993. [5] suresh kumar, p., p. mahanta, and a. dewan. study of laminar flow in a large diameter annulus with twisted tape inserts. in proceedings of 2nd international conference on heat transfer, fluid mechanics, and thermodynamics, victoria falls, zambia. 2003. [6] jedsadaratanachai, w. and a. boonloi, effect of twisted ratio on flow structure, heat transfer and thermal improvement in a circular tube with single twisted tape. journal of mathematics and statistics, 2014. 10(1): p. 80. [7] patil, j.v., m.p.p. patil, and h. patil, a review on experimental investigation of an innovative water heating system. 2016. [8] wang, y., hou, m., deng, x., li, l., huang, c., huang, h., zhang, g., chen,c., huang, w., , configuration optimization of regularly spaced short-length twisted tape in a circular tube to enhance turbulent heat transfer using cfd modeling. applied thermal engineering, 2011. 31(6-7): p. 1141-1149. [9] promvonge, p. and s. eiamsa-ard, heat transfer behaviors in a tube with combined conical-ring and twisted-tape insert. international communications in heat and mass transfer, 2007. 34(7): p. 849-859. [10] salman, s.d., kadhum, a.a.h., takriff, m.s., mohamad, a.b. cfd simulation of heat transfer augmentation in a circular tube fitted with alternative axis twisted tape in laminar flow under a constant heat flux. heat transfer—asian research, 2014. 43(4): p. 384-396. [11] yadav, r. and a. padalkar, cfd analysis for heat transfer enhancement inside a circular tube with half-length upstream and halflength downstream twisted tape. journal of thermodynamics, 2012. 2012. [12] rubbi, f., f k. habib, m. tusar, l. das, and m. t. rahman, numerical study of heat transfer enhancement of turbulent flow using twisted tape insert fitted with hemispherical extruded surface. journal homepage: http://iieta. org/journals/ijht, 2020. 38(2): p. 314-320. [13] hamzah, d.a. and k. al-farhany, effect of twisted tape ratio on the solar generator half-length pipe. journal homepage: http://iieta. org/journals/ijht, 2019. 37(2): p. 407-412. [14] manglik, r. and a. bergles, heat transfer enhancement and pressure drop in viscous liquid flows in isothermal tubes with twisted-tape inserts. wärme-und stoffübertragung, 1992. 27(4): p. 249-257. [15] manglik, r.m. and a.e. bergles, heat transfer and pressure drop correlations for twisted-tape inserts in isothermal tubes: part ii— transition and turbulent flows. 1993. [16] hong, s. and a. bergles, augmentation of laminar flow heat transfer in tubes by means of twisted-tape inserts. 1976. http://iieta/ http://iieta/ article al-qadisiyah journal for engineering sciences 13 (2020) 061–067 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: foad090@gmail.com (foad srhan jiwad) https://doi.org/10.30772/qjes.v13i1.649 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. development of the hydro static wind turbine powered ro system for maximum power point and maximum permeate flow tracking foad srhan jiwad a*, mojtaba behnam taghadosi a , ahmed abed al-kadhem majhool b a electrical engineering department, track mechatronic, imam reza international, mashhad, iran bfaculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 06 february 2020 received in revised form 16 march 2020 accepted 20 march 2020 keywords: non-desalination wind turbine hydraulic transition maximum power point tracking ro module energy recovery a b s t r a c t wind energy is one of the cheapest sources of energy that may solve the climate change problem and fresh water scarcity challenges. this article introduces a novel desalination wind turbine that is cheaper and more efficient than the common wind turbine, especially offshore wind turbine. in this system, the wind energy transmitted to the water pump by a hydraulic transmission line. the ro module is used for fresh water production. the pressure recovery module is added to ro system, to increase the permeated flow. it can be increased the permeate flow up to 45%, which is significant. the maximum power point tracking (mppt) based on the hydraulic oil pressure measurement is implemented. in addition, the maximum permeate flow tracking control loop, similar to mppt, is introduced to optimized the pressure of the ro system. it is increased the annual permeate production up to 8%. the long term performance of the system, such as annual water production is calculated and the ability of the system to mppt and the wind turbulence and gust is analyzed. the rotor speed overshoot of the closed loop system is less than 16%, which is acceptable. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction fresh water scarcity is one of the most challenging in the world now, and in the future [1,2]. the wastewater treatment and the seawater desalination plants are used to produce clean water [2]. today, most of the desalination power plants are supported by fossil fuel power stations. this means, producing more fresh water causes more co2 emission in the atmosphere. the reverse osmosis method is the most usual technology for producing clean water [3]. the ro system needs a high-pressure water pump (more than 30 bar) for producing fresh water from seawater [4]. the details for these systems are described in [5]. usually, these systems need an electrical motor to drive a water pump. however, another solution is to drive the pump directly with a diesel engine or a hydraulic motor, which eliminates electrical generator and motor, and increased efficiency of the system. in this configuration the drive system and water pump should be near each other. another serious world challenge is climate change [1]. currently, burning more fossil fuels for generating more electrical energy is not a good solution, because it will be accelerating climate change phenomena. therefore, renewable energy powered desalination system is investigated [6] and it is very popular in the world, especially for the off grid systems. wind energy is one of the important sources of clean energy. a wind turbine converts wind energy to electrical energy. wind powered desalination systems are presented in [7], which is described as the http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 62 foad srhan jiwad et al. /al-qadisiyah journal for engineering sciences 13 (2020) 061–067 principle, configurations, design, and implementation of these systems and their histories. maskus forstmeier and el.al feasibility study on a wind powered desalination project [8] also integrated wind energy desalination system is investigated by niskayuna [9]. he developed the component models of the wind, wind turbine, ro modules and analyzed the cost of water, which is showed that the wind power desalination system has a potential to be viable. in, the above references, the wind energy is converted to the electrical energy to drive ro systems. in classical wind turbine, and drive trains they consist of main shaft, gearbox, and couplings. wind turbine gearboxes are expensive and its failure has a long down time [10]. an idea to solve this problem is the hydraulic transmission system [11,12]. these systems, consist of the hydraulic pump in the nacelle, a variable displacement motor, and the electrical generator at the ground and other auxiliary components. the details of these systems are described in [13, 14]. the main advantages are:  reduction of the nacelle wight that can be reduced the tower weight and cost  easy maintenance of the generator and other components at the ground these features are more valuable for float offshore wind turbine that light weight tower and nacelle caused a great reduction in the foundation costs [14]. figure 1: general view of the desalination wind turbine in this article an efficient desalination wind turbine is described which deals with the converted wind energy to the fresh water without producing electrical energy to avoid energy waste from the energy converter to boost efficiency and reduce the overall cost (see fig. 1 for descriptions and schematic representation.). the main advantages of this concept are:  gearbox eliminating to decrease down time, nacelle weight and turbine cost, and increase efficiency of the drive train.  generator and convertor eliminating to decrease the nacelle weight and turbine cost and increase the efficiency of the power train.  by nacelle's weight reduction, the tower can be lighter, the foundation will be smaller, and the wind turbine cost will be decreased, especially for offshore wind turbine. but, this system may have some challenges as follows:  the controllability of the system and wind turbine performance in presents of the wind turbulence and wind speed sudden changes  the increased cost for the hydraulic system, which is much less than the cost of the gearbox, generator, and convertor and heavy tower. in the following sections, the desalination wind turbine is modeled and steady state behavior of the system for brackish water desalination and sea water desalination is analyzed. also the controllability of the system is investigated. 2. desalination wind turbine modeling the fluid power transmission system, which is designed for wind turbine, has many details [15]. it is consisting of many check valves, pressure control valves, accumulators, etc. for describing the concept, the main components that have important functions in the dynamic response of the system are modeled, the model is shown in fig. 2 below. figure 2: desalination wind turbine model for brackish water the wind energy is converted to mechanical energy by rotor. the rotor speed ( r )is a function of the rotor torque ( at )and hydraulic pump torque( rt ) and based on the newton second law, it can be written as [13]: a r r r r rt t b j    (1) the rotor torque has a nonlinear and complex function as follows [10]: ( , , )a r wt function v  (2)  is the pitch angle. the wind turbine specification is formed [16] and presented in table 1 below. the other parameters are also defined in table 1. more details of these equations can be found in [16]. table 1: wind turbine specification [16] rated aerodynamic power 3600 w rotor nominal speed 145 rpm number of blades 3 rotor radius 3.3m tip speed ratio 6.6 the main shaft, which is connected to the rotor, drives a hydraulic pump. the relation between pump and main shaft torque and speed can be defined as [11]: foad srhan jiwad et al. /al-qadisiyah journal for engineering sciences 13 (2020) 061–067 63 ( )r p o rt d p p  (3) o p rq d  (4) po is the hydraulic high pressure and pr is the hydraulic low pressure which is considered to be zero. the pressurized oil, transmitted energy to the hydraulic variable displacement motor. the relations are presented in equations (5) and (6) [11]. the water pump is driven by this motor, and pressurized seawater. by neglecting these pump and motor inertia, compare to the wind rotor moment of inertia, the second newton law for hydraulic motor can be written as eq. (5) and (6) and for water pump can be written as eq. (7) and (8) [11]: ( )m m o rt d p p  (5) o m mq d  (6) w w wt d p (7) w w mq d  (8) the  is the motor angular that varies from 0 to one and is related to the swash plate angle. the pw is set by the brine relief valve and is a design parameter and constant. by using eqs. (1) to (8), the dynamic relation of the wind turbine is: p a w w r r r r m d t p d b j d      (9) the brackish water is purified with the ro module and the relation between ro module variables can be written as mentioned in the table below: 0w b pq q q   (10) 0w w b b p pc q c q c q   (11) ( )p w os roq p p c a  (12) ( ) 2 b w os os c c p r   (13) the eq. (9) is the water mass balance law [12], the eq. (10) is the salt mass balance law [12], the eq. (11) is related to the ro membrane permeate flux [4,17] and the eq. (12) is the osmosis pressure relation [17]. the brackish water has a tds less than 1000 and the ro pressure is less than 40bar [9]. the system parameters for this article are calculated based on the [9] and presented in table 2. table 2: parameters definition for brackish desalination variable description value jr rotor moment of inertia 38 kg.m2 br rotor damping 0.38 n.m.s/rad dp hydraulic pump geometric displacement 22.5 cc dm hydraulic motor geometric displacement 4 cc dw water pump geometric displacement 28 cc cro ro module permeability 98.5x10-6 a ro module area 25.2 m2 ros osmosis pressure constant for salt at 25 c 0.7835 the sea water has a tds of about 35000 and the ro pressure is about 80 bar [9]. there is a significant energy waste in the pressurized brine flow. to increased system efficiency, a pressure exchanger for energy recovery from brine flow is used [18]. the availability of this module is more than 90% and the economic aspect of it is discussed in [19]. this device is very light (its dynamics are neglected compared to the wind turbine dynamics) and may have an efficiency of more than 90% and decrease the energy consumption of the ro system up to 40% [9]. the desalination wind turbine concept for seawater is presented in fig.3. in this configuration, the ro system model is changed. the relation for the system variables can be written as follows: 0w r b pq q q q    (14) ( ) 0w w r b b p pc q q c q c q    (15) ( )p w os roq p p c a  (16) r r b b recq p q p (17) the system specification for seawater desalination is calculated [9] and presented in table 3. figure 3: desalination wind turbine model for sea water table 3: parameters definition for seawater desalination variable description value dw water pump geometric displacement 8 cc a ro module area 10.5 m2 ƞrec efficiency of recovery module 0.9 the eq. (14) is the water mass balance law [5], the eq. (15) is the salt mass balance law [5], the eq. (16) is related to the ro membrane permeate flux [4,17] and eq. (17) is the energy balance relation for the recovery energy module. this module has a very fast response and its dynamics can be neglected [9]. 3. steady state analysis for brackish water desalination for assessment of the desalination wind turbine concept, a steady state condition of the system for brackish water desalination is calculated from eq. (9). the right side of this equation is set to zero and the nonlinear equation is solved for different wind speed, from cut in (3 m/s) to cut out (18 m/s). in this system, the water pressure (pw) can be tuned by a controllable relief valve. if the pw is high, the water flow is decreased (energy balance) and as a consequence, the permeate flow is decreasing. if the pw is low, the difference between water pressure and osmosis pressure is low, then the permeate flow is decreasing again. therefore, there should be an optimum 64 foad srhan jiwad et al. /al-qadisiyah journal for engineering sciences 13 (2020) 061–067 pw for maximum permeate flow. the eq. (9) for steady state is solved and optimized pw is calculated. the aerodynamic power, pitch angle and rotor speed for brackish water desalination system is plotted in the fig. 4. the wind turbine rotor starts to rotate from 3.5 m/s wind velocity (cut-in). the rated power is 3600 kw at 7.5 m/s wind velocity. in this band, which is called zone ii, the pitch angle is zero and rotor speed should be controlled to be increased from 12 rad/sec to the 15 rad/sec, linear with wind velocity, to have the best aerodynamic performance. in the zone iii, from the rated to the cut-out wind velocity, the rotor speed is constant and the pitch angle is increased to regulate rotor speed. figure 4: wind turbine variables the hydraulic oil pressure, hydraulic oil flow and the motor angular is shown in fig. 5. by increasing rotor speed in zone ii, the oil flow is increased from 20 to 50 lit/min. in order to track the best aerodynamic performance conditions (rotor speed), the water pump angle should be increased fig. 6. then the oil pressure increased consequently. figure 5: the oil pressure the optimum water pressure curve is shown in fig. 6. the permeate water flow is calculated based on equations (10) to (13) as shown in fig.6. the important parameter for a classical wind turbine is the annual power production. for this concept, the annual permeate water production (awp) is important. the awp for different annual wind speed based on the rayleigh distribution function is calculated similar to annual power production [20] and reported as in table 4. water pressure optimization can increase the annual water production by about 8%, when the annual wind speed is 3 m/s less than the rated wind speed, which is notable. but this optimization improvement, is decreased if the annual wind speed (compare to the wind turbine rated wind speed) is increased. ( ) . ( ) 8760 ( ) vw cut out p ray w w vw cut in annual water production q p v dv      (18) pray is the rayleigh probability function and 8760 is the hours in one year. table 4: annual water production annual wind velocity (m/s) 5 6 7 8 9 awp (m3) for pw = 18 bar 2936 3755 4363 4759 4963 awp (m3) for optimized pw 3165 3953 4530 4899 5081 awp increase (%) 8 5 4 3 2 figure 6: brackish desalination system variables the steady state condition of the system for sea water desalination is calculated from eqs. (9, 14-17) and table 3 parameters, similar to the brackish water desalination. the main changes between the two systems are the permeate water flow rate and the annual water production. the permeate water flow is calculated based on eqs.14 to 17 as shown in fig. 7. the awp for different annual wind speed based on the rayleigh distribution function is calculated and reported as in table 5. in this simulation, the recovery module can increase the permeate production of about 46%, which is decreased with the increase of the annual wind speed, slightly. table 5: annual water production annual wind velocity (m/s) 5 6 7 8 9 awp (m3) -without recovery system 2346 3001 3487 3805 3968 awp (m3) with recovery system 3451 4378 5060 5502 5726 awp increased (%) 47 46 45 45 44 foad srhan jiwad et al. /al-qadisiyah journal for engineering sciences 13 (2020) 061–067 65 figure 7: seawater desalination system variables 4. controller structure design for wind turbine, the capability of maximum power point tracking (mppt) is very important. for the desalination wind turbine concept, the oil pressure can be measured easily and it has a relation with a rotor angle fig. 8. therefore, it can be used for mppt. instead of the power measurement of the wind turbine generator, the rotor speed reference can be calculated from the oil pressure measurement and the command signal is sent to the water pump to set the relative angle. as it is mention in the previous section, to have the maximum permeate flow, similar to mppt for power production, this system needs a control system for maximum permeate flow tracking (mpft). refer to the figs. 4 and 8, the pw has a relation with the rotor speed, which is plotted in fig. 9. for mpft, a reference pw is calculated based on this figure and a new control loop is added to the system. the block diagram of the closed loop system is shown in fig. 10. figure 8: the hydraulic oil pressure curve for mppt figure 9: the optimum water pressure for mpft figure 10: the closed loop structure for desalination wind turbine concept it has three controller blocks: pitch controller for rotor speed regulation and oil pressure controller for mppt and water pressure for mpft. the algorithm for controller tuning is as follows:  step 1: the pitch angle controller strategy is similar to what has been assigned by [16], is chosen. this is a pid schedule gain controller. the controller gains are determined to place the poles in the desire position. more details are described in [16].  step 2: the oil pressure controller for seawater system is designed as follows (laplace domain): 6 0.25 2 10 (1 )pi s     (19) the pi parameters are set such that the closed loop system tracks the reference po and has a fast response to the sudden wind changes to prevent the rotor over speed (speed more than 180 rev/min) does not happen in the zone ii.  step 3: the water pressure controller for seawater system is designed as follows (laplace domain): 6 0.2 1 10 (1 )pi s     (20) the pi parameters are set such that the closed loop system tracks the reference pw and does not make a disturbance or vibration for the oil pressure closed loop in the zone ii. 66 foad srhan jiwad et al. /al-qadisiyah journal for engineering sciences 13 (2020) 061–067 5. results to analyzed the dynamic performance of the presented desalination wind turbine, the system is simulated in the matlab software [21], based on the nonlinear equations (section 3). the system should be stable and has not significant overshoot when the wind speed is changed and in the presents of the wind turbulence. the sea water closed loop system response to the wind variations is plotted in figs. 11 and 12. in fig. 11, the wind turbine response to the wind variation is presented. the wind velocity is changed from 4.5 to 11.5 m/s, with a sine wave shape. it is in the zone ii and iii (section 3). the pitch controller, oil pressure controller, and water pressure controller are active. the maximum oil pressure is set to 120 bar, after it, this subsystem is saturated (the relief valve will be activated). when the rotor speed is more than 145 rpm (rated rotor speed) the pitch controller is activated to regulated rotor speed. the pitch angle is increased at its maximum rate (10 deg/sec). by increasing the wind speed up to 9 m/s, the water pressure is maximized (saturated, at 79 bar). then the oil pressure is maximized (saturated at 120 bar). in this condition (wind speed between 7.5 to 9 m/s) both pitch control loop and oil pressure control loop are active. when the oil pressure is maximized, the rotor speed has the maximum overshoot (about 16%). after this point, the pitch controller has more effect and the rotor speed is reduced. the system behavior shows the stability and performance of the desalination wind turbine concept for mppt and mpft. in all wind speed the water pressure controller optimized the water pressure for maximum permeated flow and when the oil pressure is saturated, it reaches to its maximum point. figure 11: response of the wind turbine to the wind speed change the response of a wind turbine to the wind turbulence is a key factor to evaluate the control loop performance. in fig. 12, the wind turbine response to the wind turbulence is presented. the wind velocity is changed from 3.5 to 9.5 m/s to check the ability of the oil pressure and water pressure controller to rotor speed tracking (zone ii). the maximum overshoot of the rotor speed is 16% rpm, when the water pressure is saturated (at 42nd second). according to the simulation results, oil pressure or water pressure saturation causes the rotor over speed in the presence of the sudden wind speed change. therefore, using oil and water accumulator with pre-charge more than rated pressure that can store energy, may reduce the rotor speed overshoot. this investigation will be performed in the future study. figure 12: response of the wind turbine to the wind turbulence 6. conclusion in this article a novel concept for wind turbine empowered ro desalination system is introduced. the nonlinear equations of the system are derived. the pressure of the ro unit is optimized for maximum permeated flow. the steady state performance and dynamic behavior and is analyzed for seawater and brackish water desalination. for a similar condition (annual wind speed 6 m/s and without the energy recovery module) the annual permeate for brackish water desalination is about 25% more than seawater desalination. minimizing the energy usage is the goal of this concept. therefore, the pressure recovery module is used to minimize the energy demand for seawater pumping. this module can be increased the permeate flow up to 47%, which is significant. with this module for sea water, the annual permeate for seawater water desalination is 16% more than brackish water desalination without this module. this concept, has a lower component and cost, compared to the wind turbine with electricity output and a ro system. the value proposition of this concept is highlighted in the offshore wind turbine, in which the weight of nacelle and tower is very important. the next contribution of this article is the introduction of the maximum permeate flow tracking, which can be increased the output of the system about 10%, especially for area with lower wind speed, compared foad srhan jiwad et al. /al-qadisiyah journal for engineering sciences 13 (2020) 061–067 67 to the wind turbine rated wind speed. the concept can also be used for photovoltaic system, which empowers desalination plants. for this concept, an advanced control system is introduced that can have a good response to the wind turbulence. in this system a simple measurement of the oil pressure is used for maximum power point tracking which is more reliable compared to classical solutions. in addition, this concept can be used for stall wind turbine. the controller optimization and modeling details of the system can be performed in the future study. reference [1] ahmed alkaisi, ruth massad, ahmad sharifian-barforoush, “a review of the water desalination systems integrated with renewable energy”, energy procedia, 2017, pp 268-274 [2] seyedsaeid ahmadvand, behrooz abbasi, babak azarfar, mohammed elhashimi, xianh zhanh, bahman abbasi, “looking beyond energy efficiency: an applied review of water desalionation technologies and an introduction to capillary-driven desalination”, water, pp1 -30, 2019 [3] muhammad wakil shahzad, mumammad burhan, doskhan ybyraiymkul, kim choon ng, “desalination process efficiency and future road map”, entropy, pp1-14, 2019 [4] hassan a.arafat, “desalination sustainability”, elsevier, pp 150-170 ,2017 [5] jane kucera, “reverse osmosis”, wily, 2nd edition, 2015 [6] karen e. thomas, “overview of village scale, renewable energy powered desalination’, nrel, 1997 [7] gnaneswar gude , “renewable energy powered desalination handbook”, elsevier inc, 2018 [8] markus forstmeier, fredrik mannerheim, frenando d’amato, minesh shah, yan lui, michael baldea, albert stella, “feasibility study on powered desalination”, desalination, 2007 [9] niskayuna, “integrated wind energy/ desalination system”, nrel, 2006 [10] tony burton, nick jenkins, david sharpe, ervine bossanyi, “wind energy handbook”, wiley, 2011 [11] limin yang, zhiyu jiang, zhen gao, torgeir moan, “dynamic analysis of a floating wind turbine with a hydraulic transmission system”, energy procedia, 2014, pp 44-55 [12] donap rajanbhandharaks, “control of hydrostatic transmission wind turbine”, master of science thesis, department of electrical engineering, san jose state university, 2014 [13] yin zhang , xiangdong kong ,li hao, chao ai, “ controls of hydraulic wind turbine” , edp sciences, 2016, pp 1-4 [14] niels fredrik boudewijin, “on the application of fluid power transmission in offshore wind turbines”, phd thesis, delf university, 2013 [15] mackay, gary ancaster, vander straeten, ronald guelph, “wind turbine with hydrostatic transmission”, european patent application, 2017 [16] arash hatami, behnam moetakef-imani, “innovative adaptive pitch control for small wind turbine fatigue load reduction”, mechatronics, 2016, pp 1-9 [17] lewabrane, “principle of reverse osmosis membrane separation”, nakxess engineering chemistry, 2013 [18] richard l. stover, “energy recovery device performance analysis”, water middle east, 2005 [19] “the availability advantage of reliable energy recovery technologies”, energy recovey inc, 2011 [20] gilbert m. masters, “renewable and efficient electrical power systems”, wily, 2004 [21] “matlab and simulink toolbox release 2016a”, the math works, inc., natick, massachusetts, united states. https://www.google.com/search?sxsrf=acybgntizly7o_yse2ytbrowtpilf5fkow:1580494434592&q=gnaneswar+gude&stick=h4siaaaaaaaaaopge-lvt9c3neylnyjltigrvijytqqt4ksmkrrkspot9jpy87p1y4sys0ps8-ll84uyrrjlszlyixax8rnnjealfpcnfim4l6ak7mblbaanf1x_ugaaaa&sa=x&ved=2ahukewjpl9_kuk7nahvd_qqkhxruax0qmxmoataregqidxak&sxsrf=acybgntizly7o_yse2ytbrowtpilf5fkow:1580494434592 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 22 -qadisiyah journal for engineering sciences . all rights reserved. intelligent tracking control using pso-based interval type-2 fuzzy logic for a mimo maneuvering system asst. prof. dr mohammed y. hassan, university of technology, control and systems department, baghdad, iraq. email: 60003@uotechnology.edu.iq received on 3 december 2017 accepted on 22 january 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.518 abstract: air vehicle modeling like the helicopter is very challenging assignment because of the highly nonlinear effects, effective cross-coupling between its axes, and the uncertainties and complexity in its aerodynamics. the twin rotor mutli-input multi-output system (trms) represents in its behavior a helicopter. trms has been widely used as an apparatus in laboratories for experiments of control applications. the system consists of two degrees of freedom (dof) model; that is yawing and pitching. this paper discusses the design of four interval type-2 fuzzy logic controllers (it2flc) for yaw and pitch axes and their cross-couplings of a twin rotor mimo system. the objectives of the designed controllers are to maintain the trms position within the predefined desired trajectories when exposed to changes during its maneuver. this must be achieved under uncertain or unknown dynamics of the system and due to external disturbances applied on the yaw and pitch angles. the coupling effects are determined as the uncertainties in the nonlinear trms. a pso algorithm is used to tune the inputs and output gains of the four proportional-derivative (pd) like it2flcs to enhance the tracking characteristics of the trms model. simulation results show the substantial enhancement in the performance using psobased interval type-2 fuzzy logic controllers compared with that of using it2flcs only. the maximum percentage of enhancements reaches about 33% and the average percentage of enhancements is about 17.1%. they also show the proposed controller effectiveness improving time domain characteristics and the simplicity of the controllers. keywords: it2flc, trms, pso algorithm, mimo system, flc nomenclatures symbol description unit symbol description unit a1, a2 static characteristic parameters tp cross reaction momentum parameter b1, b2 parameters of friction momentum function n.m.sec2/rad 𝑢(𝑘) output of controller v al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 23 -qadisiyah journal for engineering sciences . all rights reserved. introduction trms, twin rotor mimo system, has been widely used as an apparatus in laboratories for experiments of control applications [1]. since the model is of nonlinear type with significant coupling between the two axes (yaw and pitch) and complex aerodynamics, the controlling design using conventional, hybrid and intelligent methods is researchers challenge [2-5]. fuzzy logic control (flc) is a technique to control through the investigation and description of model behavior in terms of linguistic variables formalizing the rule base [6]. different control method strategies combining flc with conventional controllers (like pd and pid), neural networks, sliding mode control and self-tuning algorithm have been used widely to control the axes of trms and track the desired trajectories efficiently [7-9]. furthermore, evolution algorithms like differential evolution (de), genetic algorithm b1, b2 parameters of friction momentum function n.m.sec2/rad u1, u2 motor voltages v b1, b2 static characteristic parameters w the constriction coefficient in pso c1, c2 acceleration coefficients in pso 𝑋 the universe of discourse e(k) error xi the position of the ith particle in pso e(k), e(k) error in pitch and yaw angles rad xgbest the previous global best position of particles in pso i1, i2 moment of inertia for the rotors in vertical and horizontal directions kg.m2 xpbesti the previous best ith position in pso 𝐿 left switch point y center of sets type reduction k1, k2 motor 1 and motor 2 gains 𝑦𝑙 left end point kc cross reaction momentum gain yout output of it2flc kgy gyroscopic momentum parameter 𝑦𝑟 right end point k proportional gain for each controller (p for pitch and y for yaw). 𝑦 𝑛 , 𝑦 𝑛 lower and upper end point kd derivative gain for each controller (p for pitch and y for yaw). �̃� type-2 fuzzy set ko output gain for each controller (p for pitch and y for yaw). e(k) rate of change of error mg gravity momentum n.m e(k),e(k) rate of change of error in pitch and yaw angles rad n number of iterations  pitch angle rad r right switch point ref pitch angle rad r1, r2 random numbers in pso  yaw angle rad to cross reaction momentum parameter ref yaw angle rad t10, t11 motor 1 denominators parameters 𝑢𝐴(𝑥, 𝑢) type-2 membership function t21, t20 motor 2 denominators parameters 𝜇𝐴̅̅ ̅(𝑥), 𝜇𝐴(𝑥) upper and lower membership functions al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 24 -qadisiyah journal for engineering sciences . all rights reserved. (ga), particle swarm optimization (pso) and artificial bee colony (abc) have been used to tune the flc parameters in order to enhance the response of tracking and minimize the steady state error [1013]. to eliminate the effect of uncertainty, achieve robustness, and enhance the performance of the controlled system in recent time, an interval type 2 flc (it2flc) was introduced as a new generation of type 1 flc. the difference in structure, mainly in the defuzzifier block, is the addition of the type reduction block during defuzzification [14]. different researches have dealt with the use of it2flc and adaptive it2flc to control the trms [14-17]. in this paper, the design of four type-2 fuzzy logic controllers for the yaw and pitch axes with their couplings of a twin rotor mimo system is discussed. the objectives of the designed controllers are to reduce overshoot and chattering, exist by the effect of external disturbances, in the yaw and pitch angles during when the trms system is exposed to changes during its maneuver. a pso algorithm is used to tune the inputs and output gains of the proportional-derivative (pd) like it2flcs to improve the tracking characteristics of the trms model. the remainder sections of this paper are as follows: section 1 describes the detailed trms model. section 2 illustrates the structure of the type-2 and interval type-2 fuzzy logic control (it2flc). the detailed steps for the design of the four pd-like interval type-2 flcs and tuning the inputs and output gains of the mentioned controllers using pso algorithm are explained in section 3 and section 4 respectively. simulation results are presented in section 5. finally, concluding remarks are provided in the section of conclusion. 1. twin rotor mimo system model the helicopter as one of flight vehicles consists of many elastic parts like rotor, control surfaces and engine. this vehicle is acted by nonlinear aerodynamics forces and gravity, and complexity increases because of flexible surfaces structures which make a realistic analysis difficult [16]. to study the control of this aerodynamics model, the trms, a lab. setup, is designed by feedback company for control experiments [1]. the main parts of trms are the beam pivoted on its base which rotates in horizontal and vertical planes freely. two rotors driven by two direct current (dc) motors located at such end of the beam. aerodynamic force through the blades and coupling effect are produced by both motors. this produces non-linear and high order system with cross coupling [18]. however, there are many differences between the trms and helicopter. the pivot point location in the helicopter is located in the main rotor head while it is located in midway between two rotors of trms. moreover, the lift generation of vertical axis in helicopter is by collective pitch control while it is generated in trms by speed control of the main rotor. finally, the yaw is controlled in helicopter by pitch angle of tail rotor blades while is controlled in trms by tail rotor speed [18]. the setup of trms is shown in figure 1 [9]. the mathematical model of the trms consists of electrical and mechanical parts where the electromechanical diagram is depicted in figure 2 and the trms schematic diagram is shown in figure 3. figure1.twin rotor mimo system figure 2. trms electro-mechanical model [1]. model (trms) [9]. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 25 -qadisiyah journal for engineering sciences . all rights reserved. figure 3. trms schematic the horizontal motion of the beam is described with the following equation: 𝐼2. �̈� = 𝑀2 − 𝑀𝐵𝜙 − 𝑀𝑅 (1) [1] where 𝑀2 is the tail propeller thrust which is a nonlinear static function of the dc motor momentum and described by: 𝑀2 = 𝑎2. 𝜏2 2 + 𝑏2. 𝜏2 (2) 𝑀𝐵∅ is the friction forces momentum represented by: 𝑀𝐵∅ = 𝐵1∅. ∅̇ + 𝐵2∅ . 𝑠𝑖𝑔𝑛(∅)̇ (3) and 𝑀𝑅 is the momentum of cross reaction approximated by: 𝑀𝑅 = 𝐾𝑐.(𝑇𝑜.𝑠+1) 𝑇𝑝.𝑠+1 . 𝜏1 (4) the electrical circuit with the dc motor is approximated by a transfer function of first or and given in laplace transform by: 𝜏2 = 𝐾2 𝑇21..𝑠+𝑇20 . 𝑢2 (5) where the input voltage of the dc motor is 𝑢2, 𝐾2 is the static gain of dc motor and 𝑇21is the main rotor time constant. moreover, the momentum equations for the vertical movement are described by: 𝐼1 . �̈� = 𝑀1 − 𝑀𝐹𝐺 − 𝑀𝐵𝜓 − 𝑀𝐺 (6) [1] where 𝑀1 is the main propeller thrust which is a nonlinear static function of the dc motor momentum and described by: 𝑀1 = 𝑎1. 𝜏1 2 + 𝑏1. 𝜏1 (7) and 𝑀𝐹𝐺 is the gravity momentum represented by: 𝑀𝐹𝐺 = 𝑀𝑔. 𝑠𝑖𝑔𝑛(𝜓) (8) the friction forces momentum is described by: 𝑀𝐵𝜓 = 𝐵1𝜓 . �̇� + 𝐵2𝜓 . 𝑠𝑖𝑔𝑛(𝜓)̇ (9) and the gyroscopic momentum is given by: 𝑀𝐺 = 𝐾𝑔𝑦 . 𝑀1. �̇�. 𝑐𝑜𝑠(𝜓) (10) the electrical circuit with the dc motor is approximated by a first order transfer function and the motor momentum is given in laplace transform by: 𝜏1 = 𝐾1 𝑇11..𝑠+𝑇10 . 𝑢1 (11) where the input voltage of the dc motor is 𝑢1, 𝐾1 is the static gain of dc motor and 𝑇11is the time constant of the main rotor. in this paper, the physical parameters of the trms model are listed in table 1 [1]. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 26 -qadisiyah journal for engineering sciences . all rights reserved. table 1. trms physical parameters [1] 2. interval type-2 fuzzy logic control (it2flc) fuzzy sets theory was introduced by lotfi a. zadeh in 1965 as a method to describe nonprobabilistic uncertainties. in 1975, the idea of type-2 flc (t2flc) as an expansion of type-1 flc (t1flc) was proposed by zadeh too. the uncertainties in fuzzy sets of membership functions (mfs) of t2flc are in three dimensions while the ones in t1flc are in two dimensions, that is the typical memberships of type-2 consists of two type-1 mfs. fuzzy memberships in type-2 have the footprint of uncertainty (fou) which is a bounded region of a fuzzy set (ã) that can handle the uncertainties, nonlinearities and linguistics related with inputs and outputs of flc and reducing them [19]. it represents the union of all primary membership functions, where: fou(ã) = ux ∈ jx (12) [21] where ã is characterized by type-2 mf uã(x, u), where x ⊂ x, x is the universe of discourse and u ∈ jx ⊆ [0, 1], then: ã = {((x, u), μã(x, u))|x ∈ x, u ∈ jx ⊆ [0, 1] } (13) in which 0 ≤ uã(x, u) ≤ 1. it can also be represented by: ã = ∫ ∫ μã(x,u) (x,u) jx ⊆ [0.1]u∈jxx∈x (14) where ∬ denotes union over all admissible x and u. the upper and lower membership functions are defined by μ̃ã̅̅ ̅(x) x ∈ x and μ̃ã(x) x ∈ x respectively, as follows: μ̃ã̅̅ ̅(x) = fou(ã) (15) [21] and μ̃ã(x) = fou(ã) (16) the secondary memberships functions (mfs) domain is within [0, 1]. moreover, the two dimension plane whose axes are u and 𝑢𝐴(𝑥, 𝑢) is known as the vertical slice of 𝑢𝐴(𝑥, 𝑢) and represented as follows: 𝜇𝐴(𝑥 = 𝑥1, 𝑢) = 𝜇𝐴(𝑥1) = ∫ 𝑓𝑥1(𝑢) 𝑢 𝐽𝑥1 ⊆ [0, 1]𝑢∈𝐽𝑥 (17) [21] where 0 ≤ fx1(u) ≤ 1 and the secondary membership function is represented by μã(x1). it is the type-1 fuzzy set where the primary membership function of x1 is jx1, it is secondary membership domain where jx1 ⊆ [0, 1] for all x1 in x. now, the interval set is defined when the secondary membership function is 𝑓𝑥1(𝑢) = 1 𝑢 ∈ 𝐽𝑥1 ⊆ [0, 1]. an interval type-2 (it2) membership function is obtained when this it is true for 𝑥1 ∈ 𝑋. the uniform uncertainty at the primary membership of 𝑥 is represented by secondary mf of type-2. the membership function a of type-2 with its secondary memberships is shown in figure 4 [20]. symbol value symbol value symbol value i1 6.8*10-2 kg.m2 kgy 0.05 sec/rad b2 1*10 -3 n.m.sec2/rad i2 2*10-2 kg.m2 k1 1.1 b1 1*10 -1 n.m.sec2/rad a1 0.0135 k2 0.8 b2 1*10 -2 n.m.sec2/rad b1 0.0924 t11 1.1 to 3.5 a2 0.02 t10 1 kc -0.2 b2 0.09 t21 1 u1, u2 ±2.5 v mg 0.32 n.m t20 1 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 27 -qadisiyah journal for engineering sciences . all rights reserved. figure 4. type-2 mf with its mfs [20]: a) fuzzy set of type-2 representing fuzzy set of type-1 with uncertain mean b) a sample type-2 fuzzy set for fou c) the secondary mf for type-2 fuzzy set d) it2flc secondary mf. type-2 flc is divided into two types; that is mamdani type where the output membership functions are fuzzy sets and the takagi-sugeno-kang (tsk) type where the output membership functions are either linear or constants. figure 5 illustrates the structure of the t2flc [19]. figure 5. structure of it2flc [1]. the difference between type-1 and type-2 flc is in the nature of the membership functions used. the main blocks of t2flc are [1]: a. fuzzifier: it makes the inference engine works by crisp inputs into type-2 fuzzy sets mapping. b. rule base: the difference between the rules in t2flc and the rules in t1flc is in the antecedents and consequents that are represented by the interval type-2 fuzzy sets. c. inference engine: the fuzzy inputs to fuzzy outputs are assigned in the inference engine block using the operators such as the intersection and union operators and the rule base. d. type-reduction: type-reduced sets are the outputs of type-2 fuzzy sets for the inference engine when converted into fuzzy sets of type-1. in interval type-2 flc three methods for typereduction operation. that are, karnik-mendel (km) iteration method, enhanced karnik-mendel (ekm) iteration method, and wu-mendel uncertainty bounds method. in this paper, modified karnick mendel is used to design the controller. it is an enhancement of the original km algorithm with three improvements. first, reducing the number of iterations, better initialization is used. second, one unnecessary iteration is removed by changing the termination condition. third, reducing the cost of computation for each iteration, a subtle computing technique is used. the detailed algorithm is given in table 2 [22]. e. defuzzification: the input to the defuzzification block is the type-reduction output block. this is done through two steps: first, by transforming the fuzzy sets of type-2 into the fuzzy sets of type-1. the left and right end points are used to calculate the type reduction sets. second, by calculating the average al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 28 -qadisiyah journal for engineering sciences . all rights reserved. of the points. crisp value (type-0) is produced by defuzzify the type-1 fuzzy generated set using the fuzzy logic control known techniques. the calculations of type-reduction operations are very complex. to simplify calculations, the interval type-2 fuzzy set is used [20]. in this paper, the centroid method is used to calculate the defuzzified values as follows: yout = yl+yr 2 (18) table 2. ekm algorithm [22] for computing 𝑦𝑟 for computing 𝑦1 step set 𝑟 = [ 𝑁 1.7 ] ( the nearest integer to 𝑁 1.7 ). 𝑎nd compute 𝑎 = ∑ 𝑦𝑛 𝑛 𝑟 𝑛=1 + ∑ 𝑦𝑛 𝑛 𝑁 𝑛=𝑟+1 𝑏 = ∑ 𝑛 𝑟 𝑛=1 + ∑ 𝑛 𝑁 𝑛=𝑟+1 𝑦 = 𝑎/𝑏 set 𝑙 = [ 𝑁 2.4 ] (the nearest integer to 𝑁 2.4 ) . 𝑎nd compute 𝑎 = ∑ 𝑦𝑛 𝑛 𝑙 𝑛=1 + ∑ 𝑦𝑛 𝑛 𝑁 𝑛=𝑙+1 𝑏 = ∑ 𝑛 𝑙 𝑛=1 + ∑ 𝑛 𝑁 𝑛=𝑙+1 𝑦 = 𝑎/𝑏 1. find 𝑟` ∈ [1. 𝑁 − 1] such that 𝑦𝑟` < 𝑦 ≤ 𝑦𝑟`+1 find 𝑙` ∈ [1. 𝑁 − 1] such that 𝑦𝑙` < 𝑦 ≤ 𝑦𝑙`+1 2. if 𝑟` = 𝑟 . stop and 𝑠𝑒𝑡 𝑦1 = 𝑦 and 𝑅 = 𝑟; otherwise. continue. if 𝑙` = 𝑙 . stop and 𝑠𝑒𝑡 𝑦1 = 𝑦 and 𝐿 = 𝑙; otherwise. continue. 3. compute s = sign(𝑟` − 𝑟). and 𝑎` = 𝑎 − 𝑠 ∑ 𝑦𝑛 max (𝑟.𝑟`) 𝑛=min(𝑟.𝑟`)+1 ( 𝑛 − 𝑛 ) 𝑏` = 𝑏 − 𝑠 ∑ ( 𝑛 − 𝑛 ) max (𝑟.𝑟`) 𝑛=min(𝑟.𝑟`)+1 y` = 𝑎` 𝑏` compute s = sign(𝑙` − 𝑙). and 𝑎` = 𝑎 + 𝑠 ∑ 𝑦𝑛 max (𝑙.𝑙`) 𝑛=min(𝑙.𝑙`)+1 𝑛 − 𝑛 ) 𝑏` = 𝑏 + 𝑠 ∑ ( 𝑛 − 𝑛 ) max (𝑙.𝑙`) 𝑛=min(𝑙.𝑙`)+1 y` = 𝑎` 𝑏` 4. set 𝑦 = 𝑦`. 𝑎 = 𝑎`. 𝑏 = 𝑏` and 𝑟 = 𝑟`. go to step 2. set 𝑦 = 𝑦`. 𝑎 = 𝑎`. 𝑏 = 𝑏` and 𝑙 = 𝑙`. go to step 2. 5. 3. design of pd-like it2flc for trms model the objective of fuzzy controllers is to maintain the trms position within the pre-defined desired trajectory. this must be achieved under uncertain or unknown dynamics of the system. the al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 29 -qadisiyah journal for engineering sciences . all rights reserved. matlab\simulink of the pd like it2flcs controlled trms system is shown in figure 6 where the trms model explained in section 1 is simulated using matlab\simulink. in order to take the effect of cross coupling between the pitch and yaw channels into consideration, four controllers are designed to control the pitch (p), pitch-yaw (pw), yaw-pitch (yp) and yaw (y). figure 6. simulink of trms controlled by it2flcs two controlled signals are generated from the outputs of the above controllers to control the pitch and yaw angles. the pitch channel is controlled signal is generated by summing the outputs of the (p) and (yp) controllers. while the controlled signal of the yaw channel is generated by summing the outputs of the (y) and (py) controllers. the inputs to the (p) and (py) controllers are the error (e(k)) and rate of error which are calculated in discrete time domain as follows: e(k)=ref- (19) e(k)= e(k)e(k-1) (20) where k is the sampling instant. moreover, the inputs to the (y) and (yp) controllers are the error (e(k)) and rate of error in discrete time domain is calculated as follows: e(k)=ref- (21) e(k)= e (k)e (k-1) (22) the inputs and output scaling factors of the four pd like it2flcs are kp, kdp, kop, kpy, kdpy, kopy, kyp, kdyp, koyp, ky, kdy, and koy where k is the proportional gain, kd is the derivative gain and ko is the output gain for each controller. these gains will be tuned manually to reach the trms position within the pre-defined desired trajectory in the pitch and yaw axes when exposed to changes during its maneuver. this must be achieved under uncertainty due to the axes coupling effects and due to external disturbances that are represented by noise signal. each controller is of mamdani type where each input and output has two trapezoid shaped type-2 membership functions within the range of (-1.5,1.5) for the inputs and (-1, 1) for the outputs, see figure 7, where the linguistic variables (n) and (p) represent negative and positive respectively. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 30 -qadisiyah journal for engineering sciences . all rights reserved. figure 7. error and rate of error mfs the rule base and the corresponding consequents of output membership functions for controller are listed in table 3. table 3. rule base and the corresponding consequents of pd like it2flc the rules are chosen to achieve minimum error in angles in both negative and positive directions. the controller equation for each controller in discrete time domain is: u(k) = k. e(k) + kd. e(k) (23) the output of each controller is multiplied by the output gain (ko).  analysis of satbility the guarantee of robustness and stability of it2flc is very big challenge because of the complexity in its structure. a bounded input bounded output (bibo) is one of the approaches to realize the stability of it2flc [17]. assume g1 and g2 are representing t2flc and the controlled plant model respectively, see figure 8. figure 8. closed loop subsystem assume the gains of g1 and g2 are 1 and 2 respectively, where 1  0 and 2  0, and 1 and 2 are constants, then: ‖𝑦1‖ = ‖𝐺1. 𝑒1‖ ≤ 𝜆1. ‖𝑒1‖ + γ1 (24) [17] ‖𝑦2‖ = ‖𝐺2. 𝑒2‖ ≤ 𝜆2. ‖𝑒2‖ + γ2 (25) according to the theorem of small gain, which illustrates that any bounded output pair (y1, y2) is generated by any bounded input pair (z1, z2), and to the stability conditions in equations (24 and 25), the system is bibo stable if y1.y2 1 [23]. 4. design of pso-based it2flc for trms model particle swarm optimization (pso) is one of the heuristic search methods which is inspired by the swarming which is introduced by kenndy and ebrhart in 1995. it has the advantages of; converging towards an optimum solution, computation is simple, and easy in implementation as 𝑒/�̇� n p n n y1 [-1, -0.9] n y2 [-0.6 -0.4] p p y3 [0.4 0.6] p y4 [0.9 1] al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 31 -qadisiyah journal for engineering sciences . all rights reserved. compared with other evolution algorithms, like genetic algorithm. each population member in pso algorithm is named as “particle”. each particle (xi(k)) “files” around the multidimensional search space with a velocity (vi(k)) of that is updated by the own experience of the neighbors of particle in the swarm [24]. in this paper, the pso algorithm with the constriction coefficient formula instead of weight is used; it's a good method that gives faster convergence ability with minimum number of iterations to reach a goal [24].the inputs and output gains (12 gains) of the four pd-like it2flcs are tuned to reach the best values depending on minimizing the following objective functions for pitch and yaw angles: iseψ = ∑ eψ 2(i)ni=1 (26) ise𝜙 = ∑ eϕ 2(i)ni=1 (27) it is the overall performance index (pi) of integral square of error (ise) for the pitch and yaw motions, as follows: ise = ∑ (ni=1 𝑒𝜓 2(i) + 𝑒𝜙 2(i)) (28) the minimization of this (pi) means that the trms model will follow the desired trajectories in both yaw and pitch motions in spite of the appearances of uncertainties in the model or the disturbances affecting them. the velocity of ith particle will be calculated as: vi(k+1)=w(vi(k)+c1r1(xpbest i(k) –xi(k)) +c2r2 (xgbest –xi(k))) (29) [25] where for the ith particle in the kth iteration, (xi) is the position, (xpbesti) is the previous best position, (xgbest) is the previous global best position of particles, (c1) and (c2) are the acceleration coefficients namely the cognitive and social scaling parameters, (r1) and (r2) are two random numbers in the range of [0 1] and (w) is a constriction coefficient given by: w = 2 |4−∅−√∅2+4∅| (30) [25] where (ϕ =c1+c2, ϕ>4). the convergence of the particle is controlling the constriction coefficient. as a result, it prevents explosion and ensures convergence. a new position of the ith particle is then calculated as: xi(k+1)= xi(k) + vi(k+1) (31) [25] the pso algorithm is repeated until the goal is achieved. 5. simulation results the physical parameters of the trms model simulated in this section are listed in table 1. the pd-like it2flc controlled system has been simulated for 100 seconds with zero initial conditions for both; pitch and yaw angles. in this simulation, the reference signals of sinusoidal wave and saw tooth with amplitude of 0.2 rad and frequency of 0.02hz and step input of 0.2 rad are applied to both angles [16]. to investigate the robustness of both controllers with respect to the measurement noise and parametric variations, a signal noise with is added to the measured variables. the measured signals from sensors are in general subject to noise in spite of the output of systems are measured using adequate sensors [16,17]. in the following simulations, a uniformly distributed random signal with amplitude of (0.01) is added to the measured pitch and yaw signals, see figure 9. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 32 -qadisiyah journal for engineering sciences . all rights reserved. figure 9. uniformly distributed random noise signal to measure the best response among all the simulations, equations (26, 27 and 28) are used. the minimization of this (ise) means that the trms model follows the desired trajectories in both yaw and pitch motions in spite of the appearances of disturbances and uncertainties applied. the inputs and output gains of the four controllers has been tuned to reach the best time response, minimum ise, and table 4 lists the best values of gains. table 4. gains of controllers obtained manually the time responses for the above three reference signals and the actual signals for the pitch and yaw angles without and with applying noise are shown in figures 10-15. the control signals for controlling the pitch and yaw motors are also shown on the same previous figures. figure 10. sinewave response of the it2flc system without applying noise 0 20 40 60 80 100 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 time, sec n o is e s ig n a l 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d actual reference 0 20 40 60 80 100 -4 -2 0 2 4 6 x 10 -3 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.5 0 0.5 time, sec y a w a n g le , ra d actual reference 0 20 40 60 80 100 -4 -2 0 2 4 6 x 10 -3 time, sec u 2 , v o lt a) b) d)c) kp kdp kop kpy kdpy kopy kyp kdyp koyp ky kdy koy 0.4 0.8 1 1 4 1 0.1 0.5 0.1 0.15 0.7 5 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 33 -qadisiyah journal for engineering sciences . all rights reserved. figure 11. sawtooth response of the it2flc system without applying noise figure 12. unit step response of the it2flc system without applying noise figure 13. sinewave response of the it2flc system with applying noise 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.5 0 0.5 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 time, sec u 2 , v o lt actual reference actual reference a) b) d)c) 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec p it c h a n g le , ra d actual reference 0 20 40 60 80 100 0 0.02 0.04 0.06 time, sec u 1 , v o lt 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec y a w a n g le , ra d actual reference 0 20 40 60 80 100 0 0.02 0.04 0.06 time, sec u 2 , v o lt a) b) c) d) 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.05 0 0.05 time, sec u 1 , v o lt 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.05 0 0.05 time, sec u 2 , v o lt actual reference actual reference a) b) d)c) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 34 -qadisiyah journal for engineering sciences . all rights reserved. figure 14. sawtooth response of the it2flc system with applying noise figure 15. unit step response of the it2flc system with applying noise in order to enhance the time response of the pitch and yaw angles with the appearance of uncertainties without and with applying noise, pso algorithm explained in section 4 is used to find the best gains of the controllers. the parameters of pso are selected as: the dimension of the swarm is 12 (number of tuned gains of the controllers), the number of birds (n=40), and (c1=c2=4). the best values of gains (global best birds) are listed in table 5 and the global best fitness is 8.8188 where the number of iterations is 25. the time responses for the same above three reference and actual signals for the pitch and yaw angles without and with applying noise are shown in figures 16-21. the control signals for controlling the pitch and yaw motors are also shown on the same previous figures. the ise for the pitch and yaw motions for both controllers with the overall ise are listed in table 6. the maximum percentage of enhancements reaches about 33% and the average percentage of enhancements is about 17.1%. 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.5 0 0.5 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 time, sec u 2 , v o lt actual reference actual reference a) b) d)c) 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.05 0 0.05 0.1 0.15 time, sec u 1 , v o lt 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.05 0 0.05 0.1 0.15 time, sec u 2 , v o lt actual reference actual reference a) b) c) d) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 35 -qadisiyah journal for engineering sciences . all rights reserved. figure 16. sinewave response of the pso based it2flc system without applying noise figure 17. sawtooth response of the pso based it2flc system without applying noise figure 18. unit step response of the pso based it2flc system without applying noise 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d actual reference 0 20 40 60 80 100 -5 0 5 x 10 -3 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.5 0 0.5 time, sec y a w a n g le , ra d actual reference 0 20 40 60 80 100 -5 0 5 x 10 -3 time, sec u 2 , v o lt 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.2 0 0.2 0.4 0.6 0.8 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.5 0 0.5 time, sec u 2 , v o lt actual reference actual reference 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.02 0 0.02 0.04 0.06 time, sec u 1 , v o lt 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.02 0 0.02 0.04 0.06 time, sec u 2 , v o lt actual reference actual reference a) b) c) d) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 36 -qadisiyah journal for engineering sciences . all rights reserved. figure 19. sinewave response of the pso based it2flc system with applying noise figure 20. sawtooth response of the pso based it2flc system with applying noise figure 21. unit step response of the pso based t2flc system with applying noise 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.02 -0.01 0 0.01 0.02 0.03 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.5 0 0.5 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.02 -0.01 0 0.01 0.02 0.03 time, sec u 2 , v o lt actual reference actual reference a) b) c) d) 0 20 40 60 80 100 -0.5 0 0.5 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.5 0 0.5 1 time, sec u 1 , v o lt 0 20 40 60 80 100 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.5 0 0.5 1 time, sec u 2 , v o lt actual reference actual reference 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec p it c h a n g le , ra d 0 20 40 60 80 100 -0.02 0 0.02 0.04 0.06 time, sec u 1 , v o lt 0 20 40 60 80 100 -1 -0.5 0 0.5 1 1.5 2 time, sec y a w a n g le , ra d 0 20 40 60 80 100 -0.02 0 0.02 0.04 0.06 time, sec u 2 , v o lt actual reference actual reference a) b) c) d) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 37 -qadisiyah journal for engineering sciences . all rights reserved. as illustrated from results and from table 6 that the pso-based pd-like it2flcs provide better performance than using pd-like it2flcs. the proposed pso based controller presents better performance and good convergence in both pitch and yaw channels with smaller oscillations. the control signals of the pitch and yaw channels for the pd-like it2flcs contain higher oscillations which causes significant error in angles than using pso based pd-like it2flcs. the less control efforts cause less consumption in power. simulation results also show the effectiveness of the proposed controller in terms of the simplicity of the controller and improving time domain characteristics. the proposed controller uses two input membership function which reduces the rules into 4 as compared with the designed ones in references (9, 13, 16, 17) which uses type-1and typ-2 flc. both controllers are bibo stable for all reference trajectories applied without and with the application of noise, see equations (24 and 25). table 5. gains of controllers obtained by pso table 6. ise performance index of trms motion conclusions type-2 flc is a highly sensitive and robust controller through perturbations and uncertainties in the controlled system as compared with type-1 flc for the same class of systems. type-1 flc has higher tracking errors especially when disturbances exist. in this paper, four pso-based it2flcs were designed for trajectory tracking for yaw and pitch axes and their cross-couplings of the 2dof trms nonlinear model using matlab/simulink. the pso algorithm is used to tune the inputs and output gains of the four proportional-derivative (pd) like it2flcs to cancel high nonlinearities and to solve high the effect of coupling. simulation results show that the pso-based it2flcs produce better stable tracking than it2flcs in terms of maintaining the trms position within the pre-defined desired trajectory, when exposed to changes during its maneuver without and with the presence of noise. the maximum percentage of enhancements reaches about 33% and the average percentage of enhancements is about 17.1%. they also show the effectiveness of the proposed controller in terms of improving time domain characteristics and the simplicity of the controllers compared with the designed ones proposed in previous published works. kp kdp kop kpy kdpy kopy kyp kdyp koyp ky kdy koy 0.487 0.168 0.922 0.787 0.561 0.897 0.534 0.496 0.027 0.121 0.535 7.745 trajectory addition of noise manual tuning of controller gains pso tuning of controller gains percentage of overall improvements (%) pitch yaw overall pitch yaw overall sine wave no 0.011 0.007 0.018 0.009 0.003 0.012 33.3 yes 0.026 0.029 0.055 0.033 0.021 0.054 1.81 sawtooth wave no 0.176 0.444 0.62 0.125 0.386 0.511 17.58 yes 0.18 0.479 0.659 0.155 0.385 0.54 18.06 unit step no 0.035 0.086 0.121 0.024 0.066 0.09 25.62 yes 1.103 1.483 2.586 0.663 1.787 2.45 6.29 o al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 38 -qadisiyah journal for engineering sciences . all rights reserved. references 1. feedback co., twin rotor mimo system, user manual, feedback co., u.k. 2008. 2. juang, j. g.; tu k. t; liu w. k., hybrid intelligent pid control for mimo system, „ proceeding of the 13th international conference of neural information processing”, hong kong, china, pp. 654-663, 2006. 3. aldebrez, f. m.; alam m. s.; tokhi m. o., hybrid control for tracking performance of a flexible system, „ proceedings of the 8th international conference on climbing and walking robots and the support technologies for mobile machines”, london, pp. 543-550, 2006. 4. juang j. g.; lin r. w.; liu w. k., comparison of classical and intelligent control for a mimo system, „applied mathematics and computation”, vol. 205, no. 2, pp. 778-791, 2008. 5. patel a. a.; pithadiya p.m.; kannad h. v., control of twin rotor mimo system (trms) using pid controller, „ proceedings of national conference on emerging trends in computer & electrical engineering”, 2015. 6. liu c. s.; chen l. r., ting c. s.; hwang j. c.; wu s. l., improvement twin rotor mimo system tracking and transient response using fuzzy control technology, „journal of aeronautics and aviation”, vol. 43, pp. 37-44, 2011. 7. mahmoud t. s.; marhaban m. h.; hong t. s.; sokchoo n., anfis controller with fuzzy subtractive clustering method to reduce coupling effects in twin rotor mimo system (trms) with less memory and time usage, „proceeding of international conference on advanced computer control”, singapore, pp. 19-23, 2009. 8. boubakir a.; boudjema f.; labiod s., a neuro-fuzzy sliding mode controller using nonlinear sliding surface applied to the coupled tanks system, „int. journal of automation and computing”, vol. 6, no. 1, pp. 72-80, 2009. 9. mahmoud t.s.; hong t. s.; marhaban m. h., investigation of using neuro-fuzzy and selftuning fuzzy controller to improve pitch angle response of twin rotor mimo system, „canadian aeronautical space journal”, vol. 56, no. 2, pp. 4552, 2010. 10. toha s. f.; tokhi m. o., real-coded genetic algorithm for parametric modeling of a trms, „proceeding of the ieee congress on evolutionary computation (cec ’09)”, pp. 2022-2028, may 2009. 11. toha s. f.; abd latiff i.; mohamed m.; kokhi m. o, parametric modeling of a trms using dynamic spread factor particle swarm optimization, „proceedings of the 11th international conference on computer modeling and simulation (uksim ‘09)”, pp. 95-100, march 2009. 12. allouani f.; boukhetala d.; boudjema f., ant colony optimization based fuzzy sliding controller for the twin rotor mimo system, „int. journal of sciences and technologies of automatic control & computer engineering ij-sta”, vol. 5, no. 2, pp. 1660-1677-dec. 2011. 13. hashim h. a.; abido m. a., fuzzy controller design using evolutionary techniques for twin rotor mimo system: a comparative study, „hindawi publishing corporationcomputational intelligence and neuroscience”, vol. 2015, no. 49, 11 pages, january 2015. 14. castillo o.; type-2 fuzzy logic in intelligent control applications, studies in fuzziness and soft computing, „soft computing”, springer-verlag, 2012. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 39 -qadisiyah journal for engineering sciences . all rights reserved. 15. kumbasar t.; dodurka m.; yesil e.; sakalli a. the simplest interval type-2 fuzzy pid controller structural analysis, „proceedings of ieee international conference on fuzzy systems, pp. 626-633, 2014. 16. zeghlache s.; kara k.; saigaa d., type-2 fuzzy logic control of a 2-dof helicopter, „central european journal of engineering”, vol. 4, no. 3, pp. 303-315, 2014. 17. maouche d.; eker i., adaptive type-2 in control of 2-dof helicopter, „int. journal of electronics and electrical engineering”, vol. 5, no. 2, pp. 99-105, april 2017. 18. elrahman m. f.; imam a.; taifor a., fuzzy control for a twin rotor multi-input multi-output system (trms), „sudan engineering society journal”, vol. 55, no. 53, pp. 19-25, september 2009. 19. mendel j. m., „uncertain rule-based fuzzy logic systems: introduction and new directions”, nj: prentice hall ptr, 2001. 20. hassan m. y.; kothapalli g., interval type-2 fuzzy position control of electro-hydraulic actuated robotic excavator, „international journal of mining science and technology”, vol. 22 , pp. 437–445, 2012. 21. . kothapalli g,; hassan m. y., compensation of load variation using fuzzy controller for hydraulic actuated front end loader, „emirates journal for engineering research”, vol. 17, no. 1, pp. 1-8, 2012. 22. wu, d.; mendel j. m., approaches for reducing the computational cost of interval type-2 fuzzy logic systems: overview and comparisons, „information sciences”, vol. 21, pp. 80-90, 2013. 23. el-nagar a. m.; el-bardini m., derivation and stability analysis of the analytical structures of the interval type-2 fuzzy pid controller, „applied soft computing”, vol. 24, pp. 704-716, 2014. 24. kennedy, j.; eberhart r., particle swarm optimization, „ieee transactions on evolutionary computation”, washington, usa, pp. 1942-1948, 1995. 25. yang x.; yuan j.; mao h., a modified particle swarm optimizer with dynamic adaptation, „elsevier –applied mathematics and computation”, vol. 189, issue 2, pp. 1205–1213, 15 june, 2007. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 332 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. development of fuzzy logic approach to optimize safety stock level in deteriorated products/a supply chain dairy industries case study riyadh jamegh phd candidate. university of technology riyadh872005@yahoo.com dr. allaeldin kassam university of technology/ department of production engineering and metallurgy/ industrial engineering branch, allakassam@yahoo.com dr. sawsan sabih university of technology/ department of production engineering and metallurgy/ industrial engineering branch, sawsanaa2006@yahoo.com abstract: in today's complex environment, a high responding ability represents a core for each organization to survive in a competitive environment. to grip your position in intense competition market, the organization must design high efficiency inventory system that has the ability to respond to changes in demand and at the same time reduce holding cost of accommodation to the lowest possible value by controlling inventory drivers such as safety stock level (ss). the traditional approaches of safety stock are limited to deal with dynamic behavior of market. advanced approaches based on soft computing allow the dynamic updating of ss level. in this paper, a highly advanced dynamic fuzzy logic (dfl) has been suggested as an innovation step to identify safety stock level in dairy industries with objective of minimizing total cost and meet with customer requirements. the proposed approach consists of three main steps firstly, identifying demand uncertainty conditions by applying fuzzy logic steps embedded by identifying dynamic (n) factor which represents the increasing level in demand in period time. secondly, identifying of raw material availability conditions by applying fuzzy logic steps, and finally, identification of inventory on hand conditions by applying fuzzy logic steps. it is necessary to identify the level of ss dynamically in fuzzy logic as an output embedded with identifying of period specification concept which describes states of demand in a specific period in which the demand is high, medium, or low which leads to identify maximum values of universe of discourse of output (safety stock). here matlab program was used. the provided solution demonstrates the proposed model validity. there has been a significant reduction in safety stock level ranging from (7-98)% depending on product type and period specification with a reduction also in holding cost, while keeping the requirements fulfillment of customers demand. key words: dynamic fuzzy logic, inventory optimization, safety stock, dairy industries, supply chain. mailto:riyadh872005@yahoo.com mailto:allakassam@yahoo.com mailto:allakassam@yahoo.com mailto:sawsanaa2006@yahoo.com journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 333 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. introduction: deterioration is defined as decay, damage, spoilage, or perishability and its effect cannot be disregarded in inventory models(yang & tseng, 2015). the performance of supply chain is greatly affected by the inventory policy followed by organizations (beheshti, 2010). so, if inventory strategy is poor, this will lead to high burdened enterprises and high holding costs. therefore, many organizations work to find the most suitable inventory strategy (yang & tseng, 2015). the shelf life of perishable products like meat , fruits, and dairy or any cooked vegetable, or grain products depends upon the specification of products and environment conditions in which that products are stored, so an efficient system of inventory is a crucial element to ensure that the products are still fresh and satisfy the customer's demand efficiently(chiadamrong & lhamo, 2017). dairy supply chain takes more attention to the products perishability, so poor network integration may lead to excessive inventory and then enormous losses(touil, echchtabii, & charkaoui, 2016). for example, m.kummu et al. (2012) noted that 25% of the global food produced was lost within the food supply chain before consumption and, roughly estimated that global food losses could be 30% to 40%. lack of effective supply chain management practices could be one of the major reasons for food losses, hence analyzing and improving food supply chains may reduce food losses(kummu et al., 2012). according to gruen et al. (2002), the rate of average stock-out is 8.3% (duan & liao, 2013), inventory annual holding costs today can be as high as 40% of inventory value (or, in some situations, even higher), while competition continually puts pressure on companies to achieve higher service levels; therefore, efficient inventory management is essential to all companies except the few that do not deal with any type of inventory(wanke, alvarenga, correa, hadi-vencheh, & azad, 2017). the products with finite shelf life which are subject to perishability are considered as an important issue and force the organizations to manage carefully. expired products consuming time and cost to rework (if it is possible) or destroy. this problem emerges significantly in healthcare or food industry where all products lose their value easily during the manufacturing process, storage process or distribution, and this explains the fact that a one third of food production is damaged(duong, wood, & wang, 2015). ghare and schrader are the first researchers who considered deterioration concept in their research. they indicated that inventories are depleted not only by demand but also by their work. they presented a model that explained how deterioration affects the inventory model(yang & tseng, 2015). the aim of this research is to provide a dynamic approach to identify safety stock and it can be implemented in different industries. 1. fuzzy inventory in perishable products fuzzy logic is considered an alternative approach to the traditional probabilistic approach which deals with ambiguity and uncertainty in inventory. fuzzy logic was emerged for the first time by lotfi a. zadeh (1965) while traditional probabilistic inventory models were used for many decades. the first use of inventory fuzzy logic was started fairly in the 90’s (kao & hsu, 2002) as that reported by (wanke et al) in 2017 (wanke et al., 2017). fuzzy inventory control for highly perishable products was presented by hideki katagiri & hiroaki ishii 2002). the objective was to maximize the profit. fuzzy shortage cost and fuzzy outdates cost were the variables of the proposed model while the fuzzy profit is the output(katagiri & ishii, 2002). multi-objective model of inventory deterioration products was developed by savita pathak & seema sarkar in 2012. the main objective was to maximize the profit of different items(pathak & sarkar, 2012). 2. literature review an improved model to identify reorder point and order quantity in dairy industry was developed by [e. khanlarpour et al 2013]. the researchers presented a distinctive model where they began using fuzzy logic to calculate the time of re-ordering rather than the amount of re-ordering as in most researches. the researchers designed a fuzzy logic system consisting of six inputs which are (air condition, competitor https://www.sciencedirect.com/science/article/pii/s0048969712011862?via%3dihub#! journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 334 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. company, customer income, religious and non-religious ceremonies, passenger & vacation, and customer satisfaction and one output (order quantity). genetic algorithm was also used to identify optimal level of order quantity. thus, researchers were able to introduce an intelligent warehouse system, which was an important shift in research(khanlarpour, fazlollahtabar, & mahdavi, 2013). the study of pricing strategy effect on inventory level was studied by panda et al in (2013) where they thought that a perishable product was a very important element of inventory system management. they also began their study by investigating the impact of price discounts policy and used dynamic pricing rather than using static pricing. dynamic pricing policy for pre and post deterioration of products was employed in order to increase the rate of inventory depletion which leads to decrease in inventory level, reduction in holding cost, and then maximization in profit. discount in prices is presented before and after starting of deterioration process. the discount with cumulative way is presented also for reduced units(panda, saha, & basu, 2013). ming-feng yang andwei-chung tseng (2015) presented a study on the effect of product perishability on inventory system. where the researcher combined traditional deterioration model with quality prediction model in order to quantize the quality and determine the remaining value of each product. (yang & tseng, 2015). rigzin lhamo & navee chiadamrong developed a simulation optimization model to study replenishment policy for each scenario in order to manage the inventory of perishable products taking into account the age of these products. arena software simulation is used in order to identify the best inventory policy taking into consideration fifo and lifo withdrawal behavior by customer. the computational results concluded that policies based products age will lead to great reduction in cost compared to the case of without inventory age of product taken into consideration(chiadamrong & lhamo, 2017). integration of location-inventory problem into scn is presented by (zhuo daia et al in 2018). the model develops optimization conditions for perishable products based on fuzzy statues for capacity and carbon emission. the authors used hybrid genetic algorithm (hga), hybrid harmony search (hhs), and lindo software to solve optimization problem under different scenarios of different capacity confidence levels and carbon emission confidence levels. through the numerical experiments, it is easy to conclude that the lindo programming is faster than hga & hhs while the last two are considered more efficient than lindo. (dai, aqlan, zheng, & gao, 2018). according to our survey about safety stock, it is clear to notice the scarcity of research that deals with safety stock by using fuzzy logic. table (1) below shows the approaches used in different researches to calculate safety stock level. table (1). summary of safety stock researches approaches. no researcher year reference tool items single multi 1 ming-feng yang & weichung tseng 2015 (yang & tseng, 2015) quality prediction model ے 2 linh n. k. duonga et al. 2015 (duong et al., 2015) simulation perishable and substitutable products 3 hui-ming wee 1997 (wee, 1997) price-dependent demand ے 4 savita pathak and seema sarkar 2012 (pathak & sarkar, 2012) fuzzy logic ے 5 s. panda et al. 2013 [14] price discounts policy applicable for different cases 6 qinglin duan,t.warrenliao 2013 (duan & liao, 2013) optimization based simulation ے journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 335 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 7 1rigzin lhamo& 2navee chiadamrong 2017 (chiadamrong & lhamo, 2017) simulation by arena ے 8 zhuo daia et al. 2018 (dai et al., 2018) optimization model with fuzzy logic ے 9 e. khanlarpour et al 2013 (khanlarpour et al., 2013) fuzzy logic & genetic algorithm just dairy firm 3. description of proposed approach the general architecture of the proposed model is shown in figure (1). the proposed model has three steps: identifying demand uncertainty level, identifying raw material level, and identifying inventory level. 3.1 general description of the proposed approach the proposed approach takes into consideration three variables and treats them by applying fuzzy logic system to identify appropriate level of safety stock. the sub section below will explain this process. 3.1.1 demand uncertainty conditions the process of employment demand uncertainty was done by following the steps below;  identification of dynamic factor (n) factor which represents maximum rate of demand increasing for a specific time period (monthly basis values were identified).  building the set of membership functions to describe the status of demand as shown in figure (2).  identification maximum value of universe of discourse which obtained by multiplying dynamic (n) factor by demand level of previous day (d(i-1) ) and this value is changed daily. identify demand of previous period d (i-1) [set input] of (fl) identify demand of current period d (i) [daily input] of (fl) n factor identify maximum value of inventory. max universe discourse. input of inventory value. daily input of inventory. identify maximum value of raw material. max universe discourse. input of raw material value. daily input of raw material. dynamic fuzzy logic system of safety stock calculation safety stock level figure (1). architecture of the proposed model journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 336 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved.  input the current day demand (d(i) ) and this value is also changed daily. 3.1.2 raw material availability raw material availability is considered as an important part in identifying safety stock level because unavailability of raw material will lead to unmet customer requirements. the steps below show how raw material availability was employed in this model;  building set of membership functions to describe the statues of raw material availability as shown in figure (3).  identifying maximum value and minimum values of raw material availability which represent universe of discourse of this variable.  input daily value of raw material availability current day (d(i) ) and this value is also changed daily. 3.1.3 inventory level on hand the level of on hand inventory is an crucial part and must be taken in account in order to identify safety stock level. suitable management of inventory leads to reduction the level of safety stock. next steps explain how inventory on hand was employed in the proposed model approach:  building a set of membership functions to describe the status of on hand inventory as shown in figure (4). 0 0.375 0.5 0.625 0.75 kkkkkkkkkkkassume n* d (i-1)= dm figure (2) fuzzy set of demand stability level. d e g re e o f m e m b e rs h ip s m h uav rav av 0 0.125 rm 0.34 rm 0.75 rm 0.9375 rm rm assume max rm=rm figure (3) fuzzy set of availability of raw material. d e g re e o f m e m b e rs h ip journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 337 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved.  identifying the max value and min values of on hand inventory to represent universe of discourse of the variable.  input of daily value of on hand current day inventory (d(i) ) and this value is also changed daily. 3.1.4 safety stock level safety stock level (ssl) is the unique output of the model. where the rules of reasoning, are applied to the system after entering of all the variables. maximum values of universe of discourse are changed daily allow high flexibility for the system and dynamic status based on period specification and this change of maximum value will be done by executing the following steps:  identifying the (dynamic value which represents period specification) ranging from (10-30)% of current period demand d(i), and the value chosen based on season conditions of product, the value is (10%) for weak period, (20)% for normal period, and (30)% for peak period.  building a set of membership functions to describe the status of demand as shown in figure (5).  identifying the maximum value of universe of discourse by multiplying (dynamic value) by demand of current the day (d(i) ) and this value is changed daily. 3.2 mechanism of safety stock identification the safety stock is calculated by applying dynamic fuzzy logic for the three pre-identified variables where the maximum value of universe of discourse of the first variable (demand stability level) is changed daily to control dynamic states for the system. the mechanism of changing this value is shown by following the procedures described in section (4.1.1), whereas for maximum universe of discourse of safety stock, the 0 0.05ss 0.08ss 0.17ss 0.2ss 0.3ss 0.32ss 0.4ss 0.42ss 0.51ss 0.54ss 0.62ss 0.65ss ss assume max ss =ss figure (5). fuzzy sets of safety stock (output variable). low little medium high v.high extreme v.extreme figure (4). fuzzy sets of inventory level. 0 0.08inv 0.16inv 0.32inv 0.4inv inv. assume maxinv =inv d e g re e o f m e m b e rs h ip low medium high journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 338 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. procedures are presented in section (4.1.4). by calling the procedures of sections (4.1.2) & (4.1.3) the maximum values of universe of discourse of raw material and inventory on hand are identified respectively. the algorithm called dynamic fuzzy safety stock (dfss) is used to identify safety stock level based on dynamic fuzzy logic; the steps below will explain this algorithm. step (1): identification of dynamic (n) factor for each product at each period. step (2): identification of universe of discourse of current period for the first variable (demand stability level) by multiplying of demand of previse period d (i-1) by dynamic (n) factor. step (3): identification of universe of discourse of the second variable (raw material availability). step (4): identification of universe of discourse of the third variable (inventory on hand level). step (5): identification of period specification for all products (ps). this specification includes the description of the period in which the demand is high, medium, or low in order to integrate with demand stability level which is identified later to know the maximum safety stock. step (6): identification of universe discourse of the unique output (safety stock level) based on period specification which was identified in step (5). 3.3 case study the examination of the proposed model validation is presented in this case study. the dairy products are considered good example of perished products, so the process of inventory optimization is crucial. high demand variability and short shelf life forced toward adapting suitable inventory approach which can deal with this complexity. demand stability level, raw material availability, and inventory on hand as inputs and safety stock as output form the fuzzy logic system to solve the problem of dairy industries company. three products are selected which are (butter 100g, yoghurt 1 kg, and cheddar cheese 100gm). it must be called the algorithm of dynamic fuzzy safety stock (dfss) which is used to optimize inventory level by identifying safety stock based on dynamic fuzzy logic as shown in steps below. in order to simplify the process we will use sample of data related to third product (cheddar 100gm) as shown in table (2). table (2). snap of required data of third product (cheddar cheese 100gm). step (1): identification of dynamic (n) factor for each product at each period. the identification of dynamic factor represents a heart of the model; it is the identification of the dynamic state of the system through which the universe of discourse of demand stability level (first variable) is identified. it is determined based on daily basis. (iffunction) excel program was employed in order to identify these values, where the change rate in demand is determined between each two adjacent periods (previous and next day). for example if the demand changed from 50 to 100, it means that the change from the first order and (n) dynamic factor is equal to (2). after applying the function for demand columns of all products for all periods, we can obtain (n) dynamic factor as shown in table (3). product month day (n) factor d(i)[deman d] max raw material daily raw material max inventory on hand inventory [first day] p3 t1 1 3 1080 30 17.09 750 128 p3 t1 2 3 45 30 9.22 750 p3 t1 3 3 1305 30 6.33 750 p3 t1 4 3 1575 30 17.5 750 p3 t1 5 3 1329 30 19.3 750 journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 339 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. table (3), the values of (n) for all selected products at (12 months). (n) dynamic factor t1 t2 t3 t4 t5 t6 t7 t8 t9 10 t11 t12 p1 0 0 5 3 5 5 4 2 3 0 4 4 p2 0 3 3 2 5 2 5 2 4 2 0 3 p3 3 3 3 2 6 2 4 3 3 3 3 3 step (2): identification of universe of discourse of the current period for the first variable (demand stability level) the universe of discourse for demand stability level is obtained by multiplying the demand of previous period d (i-1) by dynamic (n) factor. equation (1) shows the application of this process. table (4) represents universe of discourse of first variable (demand stability level) while table (5) shows the implementation of fuzzy set boundary conditions for cheddar cheese (p4) for first day. the demand of previous day is (100). max. universe of discourse for second day (dm) = d (i-1) *n (1) table (4), universe of discourse of demand uncertainty conditions. system variables linguistic variable linguistic values numerical ranges demand uncertainty condition low l (0-0.5 dm) medium m (0.375-0.75 dm) high h (0.625-1dm) from tables (2 &3), the universe of discourse for second day according to eq. (1) equals to (3*100=300) where (3) represents (n factor) for cheddar cheese in january and (100) represents the demand of previous day. table (5) shows the results of demand uncertainty universe of discourse. table (5), universe of discourse of demand uncertainty conditions for the third day. system variables linguistic variable linguistic values numerical ranges demand uncertainty condition low l (0-0.5 ) *300 medium m (0.375-0.75 ) *300 high h (0.625-1) *300 step (3): identification of universe of discourse of the second variable (raw material availability). universe of discourse of second variable (raw material) is identified on monthly basis, while daily level of raw material is entered to the model to identify the impact of this variable on safety stock (ss) level. table (6) shows the universe of discourse of this variable while table (7) presents the value of universe of discourse of the variable in january where max level of raw material is (30ton). table (6), universe of discourse of raw material availability conditions. raw material availability unavailable uav (0-0.34 rm) rare available rav (0.125-0.9375 rm) available av (0.75-1rm) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 340 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. table (7), universe of discourse of raw material availability conditions for january. raw material availability unavailable uav (0-0.34) *30 rare available rav (0.125-0.9375) *30 available av (0.75-1) *30 step (4): identification universe of discourse of the third variable (inventory on hand level). inventory on hand universe of discourse and fuzzy sets are identified in this step, table (8) shows the universe of discourse of this variable and table (9) presents the value of universe of discourse of the variable in january where maximum level of on hand inventory is (75 packages). table (8). universe of discourse of inventory on hand conditions. on hand inventory low l (0-0.16 inv) medium m (0.08-0.4 inv) high h (0.32-1 inv) table (9). universe of discourse of inventory on hand for january. on hand inventory low l (0-0.16)*750 medium m (0.08-0.4) *750 high h (0.32-1) *750 step (5); safety stock level (output) only one output i.e. safety stock level is determined by this model. seven sets are used to identify the ss level. it is crucial to identify period specification. in january for the cheddar cheese the period is peak, so the percentage is (30%) of d(i), while for yogurt 400gm the period specification is (20)% of d(i). for example, the max universe of discourse of the first day of january of cheddar cheese is (0.3*1080) where (0.3) represents the period specification value and (1080) represents the demand of first day. table (10) shows the universe of discourse of ss level while table (11) presents the value of universe of discourse of the first day for the cheddar cheese in january where max level of ss is changed daily. table (10). universe of discourse of ss level. safety stock level low l (0.-0.08 ss) little li (0.05-0.2 ss) medium m (0.17-0.32 ss) high h (0.3-0.42 ss) very high vh (0.4-0.54 ss) extreme e (0.51-0.65 ss) very extreme ve (0.62-1 ss) journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 341 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. table (11). universe of discourse of ss level for soft cheese in third day of january. safety stock level low l (0.-0.08)*324 little li (0.05-0.2)*324 medium m (0.17-0.32)*324 high h (0.3-0.42)*324 very high vh (0.4-0.54)*324 extreme e (0.51-0.65)*324 very extreme ve (0.62-1)*324 referring to table (2) and in order to simplify the process, third product (cheddar 100gm cheese (p3)) parameter was selected for (january), when calculate ss for first day. the demand of the previous period equals to (100) package with inventory on hand equals to (128) package and raw material available of (30) tone of raw milk, and demand of current day is (1080) package, then the safety stock is (116) package. depending upon the specific percentage which mentioned in proposed model i.e. (max.ss= 30% of d(i)), ss= 30%*1080=324 and then distribute all percentage values as shown in figure (5). figure (6) shows the results of ss level for (p3) in the first day of january the mechanism of dynamic fuzzy logic represents continuous change (depending on the specific time period) of fuzzy system which depends on the change occurred in universe of discourse of one or more of included variables, which results in a flexible system that deals with these changes that occurred periodically and thus lead to obtain high accuracy results. figure (7) illustrates the dynamic behavior of fuzzy logic. figure (6); implication process for identifying ss level for third day of january for soft cheese 0 92 140 203 324 fuzzy inputs applying and operator (min) applying implication process aggregation results if demand stability is high and raw material is rare and inventory is medium r23 journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 342 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. by applying the proposed model on the case study parameters, great results were obtained. clear reduction in ss level for all products is gained while keeping customer satisfactions, the reduction of ss level is varying between (7-98)% as shown in table (12); table (12). percentage reduction in ss level for three products in 12 months. in order to provide detailed description about the obtained results, table (13) shows the values of the original demand, current ss level (identified by company), and safety stock of proposed model for butter 100gm product in january. the (current ss) for butter 100gm in march is (1219) and the (developed ss) is (74), so the reduction is about 93% as mentioned in table (13): table (13). demand, current ss and developed ss for p1 (butter 100gm ) in (t3). butter 100gm (march) butter 100gm (march) percentage impact of the proposed approach on safety stock t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 p1 0 0 93% 93% 93% 96% 96% 93% 92% 0 87% 88% p2 97% 96% 97% 96% 96% 96% 96% 91% 92% 97% 97% 98% p3 35% 7% 86% 68% 72% 82% 87% 86% 81% 95% 74% 72% figure (7) dynamic mechanism of proposed fuzzy logic approach 0 0.375 0.5 0.625 0.75 kkkkkkkkkk kassume n* d (i-1) = dm m e m b e r sh ip fu n c ti o n s m h n factor demand 3 1080 3 45 3 1305 3 1575 3 1320 3 1435 3 577 3 1166 3 1665 3 1150 3 1295 3 1365 3 770 3 1380 3 1570 3 1345 specification demand 0.3 1080 0.3 45 0.3 1305 0.3 1575 0.3 1320 0.3 1435 0.3 577 0.3 1166 0.3 1665 0.3 1150 0.3 1295 0.3 1365 0.3 770 0.3 1380 0.3 1570 0.3 1345 low little med. high v.high extreme v. extreme m e m b e r sh ip fu n c ti o n 0 0.05ss 0.08ss 0.2ss 0.32ss 0.42ss 0.54ss 0.62ss ss kkkkkkkkkk kassume max ss = ss journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 343 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. day demand current ss developed ss day demand current ss developed ss 1 14 61 2 12 18 32 2 2 92 19 23 13 22 60 2 3 66 3 3 14 15 45 2 4 41 112 2 15 16 79 2 5 18 94 2 16 24 55 2 6 48 46 6 17 6 49 1 7 40 6 3 18 20 79 5 8 23 83 2 19 13 66 1 9 21 62 2 20 20 46 2 10 46 66 5 21 8 38 1 11 16 50 1 22 20 68 3 sum=1219 sum=74 reduction= 93% conclusions in today's dynamic and global market environment, it is very important to use advanced approaches rather than traditional ones to identifying safety stock (ss) level. this seems more important when applied in the dairy industry due to the short shelf life of products and high competitive situations, which made the application of soft computing techniques absolutely indispensable. as the experience of the model on more than one product which has different specifications in terms of the dynamic factor and the amount of demand stability level proved the importance and success of the proposed model. moreover the implementation of dynamic fuzzy logic in identifying ss level leads to more control on demand variation by employing an expert knowledge which enables the owners to overcome the problem of excessive inventory level due to reliance only on common statistical equations. the dynamic fuzzy logic has an excellent ability to deal with the advanced global market which is characterized by dynamic and competitive nature. it is crucial to notice that the dynamic fuzzy logic is considered as flexible tool because the dynamic input variable i.e. (demand level) and dynamic output variable (safety stock) can be readjusted and modified easily. despite the success of the proposed model, there are some future areas of research, such as the use of advanced techniques in identifying inference rules, which gives the models high robustness in the identification of outputs. journal of al-qadisiyah for engineering science vol. 11, no. 3 issn: 1998-4456 page 344 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. references 1.beheshti, h. m.. a decision support system for improving performance of inventory management in a supply chain network. international journal of productivity and performance management, (2010), 59(5), 452-467. 2.chiadamrong, n., & lhamo, r.. inventory management of perishable products in a retail business: a comparison with and without in-store replenishment policies under different purchasing batch sizes. international journal of logistics systems and management, (2017), 26(2), 224-252. 3.dai, z., aqlan, f., zheng, x., & gao, k.. a location-inventory supply chain network model using two heuristic algorithms for perishable products with fuzzy constraints. computers & industrial engineering, (2018), 119, 338-352. 4.duan, q., & liao, t. w.. a new age-based replenishment policy for supply chain inventory optimization of highly perishable products. international journal 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[1]. liquid membrane can be expressed as a semi-detachable partition formed by a thin, non-porous, layer of organic solvent. this membrane separates two aqueous phases, which are the source phase (or the feeding phase or the donor phase) and the receiving phase (or the abstraction phase or the stripping phase). the pollutant is transferred from one aqueous phase (external phase) to another phase (stripping phase), according to the difference in concentrations or the extracting effect, through the organic membrane. this transfer process is called “protraction” kislik et al. [2] the first appearance of the term liquid membrane was in 1902, when it caught the attention of a researcher by chance, while studying the properties of systems consisting of oil layer and electrolytic solutions, the presence of a strong film in the interface of water and oil was observed. http://qu.edu.iq/ mailto:salih.rushdi@qu.edu.iq https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ downloads/aaa.docx#corresponding_author fatima f. jabbar & salih a. salih /al-qadisiyah journal for engineering sciences 13 (2020 ) 232–239 233 so much so, that the ring used in the du nuoy experiment, to measure the surface tension between liquids, can bind the film and raise it to the oil phase. after that, these films were thought about and how to benefit from them. therefore, the first experiment in this field was conducted in 1968 by the researcher lei, who obtained a patent for the separation of hydrocarbons using liquid surface films. li et al. [3] in the past two decades, this technology has evolved into an accepted separation. due to the strict environmental legislations and the characteristics that distinguish this technology from the traditional separation processes, the interest of researchers in this field has been increased, where many researches has been done in the field of membrane development, building the unity of the process, the extent of its use in various fields and so on. román et al. [4] liquid membrane applications can be implemented using units with different designs of liquid membranes. therefore, liquid films can be classified according to these designs into bulk liquid membrane (blm), supported liquid membrane (slm), and emulsion liquid membrane (elm) moyo et al. [5]. figure 1. schematic of elm ahmad et al. [7] the emulsion liquid membrane (elm) can achieve much higher mass transfer. elm extraction provides a high ratio of surface area to volume, for high mass transfer, more economy, low energy consumption, and effective for low solubility concentration and small quantity solvent requirements zaulkiflee et al. [6]. in the liquid membrane design fig. 1, the elm unit consists of an internal phase (reception solution), an organic phase (liquid membrane), and an external phase ( feeding solution ). lems are made by forming emulsions from the inner phase and the organic phase, then dispersing these emulsions in the outer phase (feeding solution). in lem extraction, extraction and abstraction operations are combined into one-step process muesli et al. [8]. .in a typical arrangement, the strip solution and the organic phase are emulsified to form very fine droplets of the dispersed inner solution in the organic phase. the organic phase may contain a conventional solvent recovery reagent to facilitate the transport of the pollutants through the organic membrane. although this method is very effective, its commercial and industrial applications are still limited so far due to “emulsion instability”, this term means membrane leakage, fusion, and emulsion swelling. the instability of the emulsion globules will reduce the extraction efficiency. on the other hand, the highly stable emulsion causes new problems during sedimentation and de-emulsification ahmad et al. [7]. the efficacy of the membrane on extraction and the stability of the emulsion are essential criteria for evaluating the performance of the emulsion membrane. these two criteria are affected by several factors, including factors related to the installation of the membrane and others related to the operational conditions. 1.1 removal of heavy cadmium ions by elm: one of the well-known toxic heavy metal ions is cadmium ion. this ion can accumulate through the food chain and seriously affect the health of living organisms. cadmium is discharged at high concentrations in wastewater from the nickel-cadmium battery manufacturing plants, cadmium alloys, iron processing plants, etc. therefore, the process of separating cadmium has taken great care in the field of research to find a feasible and effective method to purify industrial water renieri et al. [9]. among these studies is the field of elm performance improvement, which is considered as a promising and cheaper separation method of cadmium .. kumbasar et al. [10] studied the removal of cadmium from a solution resulting from the filtering of the zinc cake with sulfuric acid.by using lem technique. the effect of acid concentration in outer solution, type of stripping solution, concentration of stripping solution, mixing speed in feed solution, surfactant concentration, carrier concentration, cadmium concentration in the extraction, and phase ratio on the rate of cadmium removal was studied. the elm consists of kerosene as an economical organic solution and contains aliquat336 as a carrier and span80 as a surfactant. a different stripping agent was examined, it was found that ammonia solution is more favorable than , and naoh. solutions. it was also concluded that the use of a sufficient quantity of the carrier had a positive effect on increasing the efficacy of pollutant extraction and the speed of recovery, but in any case the amount of extracts used in this technique remains generally low. ahmad et al. [11] studied the application of green liquid emulsion membrane technique to remove cadmium by using vegetable oil as a diluent, which contained span 80 as a surfactant and different types of carrier. they studied the stability of green emulsions in front of several variables, including carrier type and concentration, surfactant concentration, emulsification time, internal phase concentration, and stirring speed. according to the results reached in this study, the use of high concentrations of the carrier and the surfactant in the membrane layer increases the possibility of membrane fracture. although the use of a high-viscosity emulsion layer causes a high resistance to mass transfer, the results showed that the emulsion was more stable and the fraction ratio reached 0.05% after improving all parameters of the process. nomenclature c: cadmium ions concentration after t=t t d. taguchi’s design c0: initial concentration of cadmium ions t=0 n: is the number of times the experiment was repeated under the same conditions elm emulsion liquid membrane df : degree of freedom eml./ext. emulsions to external phase ratio. v/v : volume by volume d o e : design of experiments w/o : water in oil emulsions y: response amount. 234 fatima f. jabbar & salih a. salih /al-qadisiyah journal for engineering sciences 13 (2020 ) 232–239 benderrag et al. [12] studied the recovery of cadmium from stream water using elm consists of kerosene as an organic solvents; triton x100 as a stabilized biodegradable surfactant and di-(2-ethylhexyl) phosphoric acid (d2ehpa) as carrier. cd (ii) extraction yield, y (%), quantifying the efficiency of the process, was considered as a function of three parameters: d2ehpa/triton x-100 ratio ranging from 0.5 to 3.5, initial feed phase concentration between 300 and 500 ppm, and feed phase ph from 5 to 9. at the optimized conditions ([cd] =500 ppm, stirring speed=200–300 rpm, t=20 min and ph=7.6), cd (ii) ions extraction was recorded more than 98% of efficiency. this study by binnal et al. [13] this study was distinguished from the previous two by reviewing the effect of temperature on cadmium extraction by the elm method. they explained that the extraction reaction of the cd(ii) is favored by a relative decrease in the temperature. in this study, a taguchi method was adopted to explain the change in the concentration of cadmium ions in the outer phase, where the effect of five variables ( ph of external phase, carrier concentration, surfactant concentration, emulsification speed, and emulsion to external phase ratio) on the process were investigated. table 1. required materials materials specifications suppliers kerosene mw. =51.5 g/mol purity ≥ 99% density = 0.8 g/cm3 dwaniyah refinery aliquat 336 (methyltri-octyle ammonium chloride mw. =404.16 g/mol purity ≥ 97% density = 0.884 g/cm3 sigma aldrich span 80 mw. =428.62 g/mol purity ≥ 60% density = 1.06 g/cm3 thomas baker sodium hydroxide (naoh) mw. =40 g/mol purity ≥ 97.5% thomas baker cadmium chloride mw. =201.32 g/mol purity ≥ 99% central drug house hydrochloric acid mw. =36.46 g/mol concentration ≥ 36% reagent 2. experimental work: 2.1 required materials : table 1 includes the materials used in the present work with their specifications and the companies supplying them. these materials were used without further purification. 2.2 required equipment :  mixer (bensonmooth /standard-germany)  homogenizer (om-tops)  syringe filter (chmlab group)  atomic absorption spectrophotometer (shimadzu). figure 2. general description of experimental work. 2.3 experimental procedure : the method of work includes four steps hussein et al. [14] that can be summarized as follows : 1. preparation of solutions step : three required solutions were prepared:  the organic solution: is prepared by dissolving the carrier(aliquat 336) and surfactant (span80) in a kerosene solvent according to the certain determined as variables.  external solution: prepared by dissolving a specific amount of cadmium chloride in distilled water to obtain aqueous cadmium solutions at a concentration of 100ppm. the ph value of this solution is controlled using hydrochloric acid & naoh solution.  stripping solution: it is prepared by dissolving a specific amount of naoh to obtain a basic solution at a concentration of 0.1 m. 2. emulsification step (w/o) : in order to obtain stable emulsions, a stripping solution was added gradually to the organic solution in ratio 1:1 ( v/v ). this mixture was then emulsified by using the homogenizer at different mixing speeds according to the conditions of each experiment. mixing was continued until a steady milky emulsion is obtained. this process is taken about 12min, and the emulsifying cup is placed in a cold water bath to avoid overheating of the emulsion during preparation. 3. extraction step: the prepared emulsions were gradually added to 400ml of the 100 ppm cadmium aqueous solution. this system was mixed using a mixer at a speed of 250rpm for a period of 10min. samples were taken after every 3min and 10min, the external solution of the sample is separated from the emulsions using a filter syringe. 4. sample analysis: the concentration of cadmium in the samples was measured using atomic absorption spectra-photometer. these concentrations were then used to determine the cadmium concentration change in the external phase. 2.4 transport mechanism: the general steps of the ions transport process between the three phases of the emulsion liquid membrane unit (external phase, organic phase, and internal phase in series) are as follows koter et al. [15]: (1) diffusion of metal ions from the depth of the feed phase to the surface where the feed phase meets the organic phase, (2) the complexity of metal ions with the carrier on the convergence surface to form mineral complexes dissolved in the organic phase, fatima f. jabbar & salih a. salih /al-qadisiyah journal for engineering sciences 13 (2020 ) 232–239 235 (4) 4 (aq) -2+ cdcl (aq)+ 2na (aq)) -oh+n4+ 2(r (aq)+ 2naoh (org) 4cdcl2n)4(r (aq)o2+ 2h(org) 4cdcl2n)4r( 4 (aq) -2+ cdcl(aq) + 2h) (org) -oh+n42(r (3) these complexes diffuse through the organic layer in addition to the confluence of the organic phase with the inner phase, (4) dissociation of the mineral organic complexes on this side, as mineral water complexes form, then spread throughout the inner phase. aliquot 336 is one of the quaternary ammonium halides more efficient for extracting metal ions from an aqueous halide medium. the extraction mechanism is an ion bonding mechanism to produce neutral types, whereby quaternary ammonium compounds balance the charge of ionic mineral complexes, and thus the process is called enhanced extraction. the proposed general extraction mechanism is as follows kumbasar et al. [10]: (1) where : nr4n +a = quaternary ammonium halides , (mbx)= ionic groups are in the external phase , (r4n+)n(mbx) = carrier-ion complex. in this study (cadmium extraction), an ion exchange reaction with aliquat 336 (r4ncl) occurred on the surface of the membrane to form an ion pair ((r4n)2cdcl4 ) that then enters the emulsified liquid membrane layer. for the feed solution, cadmium ions interact with chlorine ions (cl-) in proportion to the following equation he et al. [16]: (2) the process of forming complexes on the side of the confluence of the outer phase with the organic phase can be described by the following chemical reaction juang et al. [17] : (3) where in this reaction, clis interchanged with the cdcl4 2− anion in the acidic feed solution–membrane interface. the compound formed as above is dispersed through the membrane towards the abstraction side, and when there is naoh there, the next reaction is expected to occur on the membrane face on the side of the internal solution : in this reaction, cdcl4 2− is interchanged with the oh−anion in the basic stripping solution–membrane interface. then the carrier complex (r4n +oh-) is returned to spread in the organic layer where the exchange reaction between the sides of the extract and the abstraction takes place as follows: (4) where aliquat 336 turns into a hydroxide in a certain ratio by contacting with stripping naoh solution bhowal et al. [18]. 3.design of experiments (doe) : this work includes five variables (ph of external phase, surfactant to kerosene ratio (v/v), carrier to kerosene ratio (v/v), emulsification speed, and emulsions to external phase ratio (v/v)). each variable was taken at four levels, as shown in table 2. table 2. work’s variables no. variables level 1 level 2 level 3 level 4 1 ph of external phase 1 2 3 4 2 span 80 ratio (v/v) 4% 6% 8% 10% 3 carrier ratio (v/v) 4% 6% 8% 10% 4 emulsification speed (rpm) 5800 12700 19700 24000 5 eml./ext. ratio (v/v) 6/100 10/100 14/100 18/100 one common method of designing experiments is the taguchi approach to reducing the number of experiments needed to work, and to illustrate the impact of each factor. taguchi design (td) experiment method is a very popular method due to its high applicability and ease of use with limited knowledge of the basics of statistics. this method was developed by dr. genichi taguchi based on the design principles that emerged in the fifties and sixties, this method can be defined as "an engineering methodology to improve productivity during research and development so that high-quality products can be produced quickly and at low cost." it can be used in various research fields. menten et al. [19]. essentially, the taguchi method is characterized by dar et al. [20]:  its ability to study all process parameters using a few number of experiments.  finding the parameter that most influences the response rate. the first step in this method is to determine the controllable factors (factors & there levels mentioned in table 2 ) and the factors that cannot be controlled (response ). in this method, orthogonal matrices are used to calculate the number of experiments and rely on the results of these experiments to analyze the data. calculating the number of trials using the taguchi method depends on the degree of freedom (df). in this study there are five variables and four levels, df= (1 + 5 * (4-1)) = 16. therefore, when selecting the orthogonal matrix l16, the number of experiments will be 16. sulaymon et al. [21]. table 3 represents orthogonal matrices are used to calculate the number of experiments based on td method in coded form using minitab v 17.0. so that the experiments were conducted in the same sequence shown in table 4 in terms of real values. in td the data is analyzed using the following analysis methods provided by this method design-of-experiments et al. [22]:  the signal / noise ratio indicates parameters of quality features for testing. average analysis,  anova variance analysis to determine the effect of each factor. table 3. orthogonal matrices of l16 in terms of coded values. no. a b c d e 1 1 1 1 1 1 2 1 2 2 2 2 3 1 3 3 3 3 4 1 4 4 4 4 5 2 1 2 3 4 6 2 2 1 4 3 7 2 3 4 1 2 8 2 4 3 2 1 9 3 1 3 4 2 10 3 2 4 3 1 11 3 3 1 2 4 12 3 4 2 1 3 13 4 1 4 2 3 14 4 2 3 1 4 15 4 3 2 4 1 16 4 4 1 3 2 nr4n +a(org) +(mbx) n(aq) (r4n +)n(mbx) n(org) +na(aq) 2h+(aq) + cd 2+ (aq) + 4cl (aq) h2cdcl4(aq) 2h(aq) + cdcl 24 (aq) 2r4ncl (org) + cdcl 24 (aq) (r4n)2cdcl4 (org) + 2cl 236 fatima f. jabbar & salih a. salih /al-qadisiyah journal for engineering sciences 13 (2020 ) 232–239 table 4. orthogonal matrices of l16 in terms of real values. 4. results and discussion : 4.1 effect of process parameters on c/c0 4.1.1 effect of ph of external phase : the effect of each ph level on the extraction process is shown in fig. 3 as shown in the graph, the highest cd+2 extraction is the value of ph = 3, that is, the lowest value of the remaining cd+2 ions in the external solution. according to the chemistry of extraction by basic carrier (aliquat 336) that was used in this study, it can be explained that at very low ph values there is difficulty in separating cdcl4 2− complex from cdcl4 stable complex. increasing the value of ph more than 3 (decrease in the amount of hydrochloric acid) causes a decrease in the transmission rate due to a decrease in the number of halide (chloride) ions that are needed to form the complex cdcl4 2− [10],[16]. 4.1.2 effect of surfactant concentration: the effect of each level of the surfactant factor concentration on the extraction process is shown in fig. 4. it can be deduced from the graph that the lowest value of the remaining cd ions in the external solution occurred at the concentration = 0.04. increasing the concentration of the surfactant from the required limit leads to an increase in the viscosity of the organic layer, which leads to a high resistance to the mass transfer process due to the difficulty of spreading complexes through the organic layer. also increasing the viscosity causes the formation of large-size pellets during the dispersion phase, which causes a reduction in the moving area naim et al. [23]. 4.1.3 effect of carrier concentration: fig. 5 shows the effect of each level of the carrier concentration on the extraction process. the concentration of the remaining cd ions in the outer solution decreases gradually until it reaches the carrier concentration = 0.08. then increase slightly when the focus = 0.1. increasing the concentration of the carrier leads to an increase in the number of complexes present during the organic membrane, which may lead to swelling of the emulsion pellets, then reducing the transfer area, as well as swelling of the pellet to reduce the organic membrane, which makes it susceptible to fracture and the internal phase leakage outward ahmad et al. [11]. figure 3. effect of ph of the external phase. figure 4. effect of surfactant concentration. figure 5. effect of carrier concentration. 4.1.4 effect of emulsification speed: as shown in fig. 6 the amount of cadmium ions remaining in the outer phase decreases with increasing emulsification speed, i.e. the separation efficiency increases. increasing the speed of emulsification no. ph of external phase surfactant conc. v/v % carrier conc. v/v % emulsification speed eml./ext. ratio % 1 1 4 4 5800 6 2 1 6 6 12700 10 3 1 8 8 19700 14 4 1 10 10 24000 18 5 2 4 6 24000 18 6 2 6 4 19700 14 7 2 8 10 5800 10 8 2 10 8 12700 6 9 3 4 8 24000 10 10 3 6 10 19700 6 11 3 8 4 12700 18 12 3 10 6 5800 14 13 4 4 10 12700 14 14 4 6 8 5800 18 15 4 8 6 24000 6 16 4 10 4 19700 10 fatima f. jabbar & salih a. salih /al-qadisiyah journal for engineering sciences 13 (2020 ) 232–239 237 figure 6. effect of emulsification speed . provides more homogeneity between the organic membrane and the internal phase. this homogeneity provides more stable dispersible pellets of an appropriate size so that it can provide sufficient transport space to obtain the largest value of the mass transfer coefficient during the work. dong et al. [24]. 4.1.5 effect of eml./ext. ratio : from fig. 7, it can be concluded that the concentration of the remaining cadmium ions is completely inversely proportional to the eml./ext. ratio, meaning that the efficiency of cadmium ions extraction using elm technique increases with this ratio. this can be attributed to the increase in the contact area between the external phase and the emulsions and thus increasing the area of the mass transfer. in addition to the increase in the amount of abstraction phase, it can also lead to preventing the occurrence of the reverse transition resulting from the accumulation of complexes traveling in the organic phase, which leads to the emulsion being swollen and broken. zaheri et al. [25]. figure 7. effect of eml. / ext. ratio. 4.2 sign /noise analysis: in taguchi method for determining process quality, the signal-tonoise ratio is used. where the signal represents a desirable value (average response value), while noise is undesirable values (the square deviation of the response from the desired value). there are three possible signal/noise ratios, which depend on the system quality improvement standard. these ratios are divided into larger is better (lib), used when the largest value of a response is needed without compromising the reliability of the process. small is better (sib), used when the goal is to get the lowest value of the response. nominal value is better (nib) and, used when the response value needs to be around a certain value pundir et al. [26]. in this study, to find out the main effects of the variables and levels mentioned in table 2, the "smaller is better ", represented by the equation (6), was used to calculate the signal-to-noise ratio. signal/noise = 10 log (1/n ( )) (6) since the sib used, the highest s / n ratio is required to obtain the lowest concentration of cadmium ions in the external phase fouad et al. [27] shown in fig. 8 and table 5. where the effect is chosen that achieves the smallest value from the mean of c/c0. calculations were performed using the program "minitab® 17.1.0", knowing the effect of each factor on the response represented by table 5, and fig. 8. table 5. response table for signal to noise ratios ‘smaller is better’ level ph surfactant conc. carrier conc. emulsification speed eml./extr. ratio 1 22.09 23.61* 22.48 22.08 21.6 2 23.12 23.14 23.07 23.01 22.24 3 23.77* 22.96 23.61* 23.73* 23.87 4 23.47 22.74 23.29 23.63 24.74* delta 1.67 0.87 1.13 1.65 3.14 rank 2 5 4 3 1 *optimum level as shown from table 5 signal /noise ratio ranged from 21.6 24.74, the table includes ranks of the variables based on delta values, which compare the extent to which each variable affects the response (represented by the c/c0) dar et al. [20]. therefore, the order of the variables in terms of the magnitude of the effect in a descending form is as follows: eml./extr. ratio > ph of external phase > emulsification speed carrier conc. >surfactant conc. figure 8. main effects plot for sn ratios of c/c0. 238 fatima f. jabbar & salih a. salih /al-qadisiyah journal for engineering sciences 13 (2020 ) 232–239 so the optimum level of effectors that achieves the smallest value of c/c0. will be:, eml./extr. ratio = 18/100, ph value =3, emulsification speed = 19700 rpm , and surfactant concentration = 4%, and the carrier concentration = 8% . from fig. 9, which represents the mean of c/c0. for each influencing factor. if the line is not horizontal, it means that the factor has a significant impact on the response rate, and also means that the effect of the levels varies with the different factor. where the effect of the factors can be compared by comparing the slope of the lines represented by them. in the event that the lines are parallel to the x-axis, this means that all levels of factors affect the same way and also have no significant impact on the response rate. hameed et al. [28] figure 9. main effects plot for means of c/c0. 4.3analysis of variance (anova) : anova is a statistical technique that can draw some important conclusions based on empirical data analysis. this method is very useful for detecting the effect of each factor on the response value. table 6 includes the most important elements of the analysis of variance. table 6. analysis of variance for cadmium extraction by elm. response source contribution % f-value p-value c/co ph 77.11% 77.21 ....2 surfactant conc. 7..1% 7..7 ..710 carrier conc. 2.71% 2..2 ...10 emuls. speed .0.71 % 71.20 ....7 eml./ext. ratio 2..10% 27.17 ..... these elements include: the percentage of contribution (contribution%) which gives the percentage of each factor's contribution to affecting the response value. as for the work variables, it can be noted that the eml./ext. ratio has the greatest effect on changing the response rate, it has 53.6% of the effect of c/co. f-value indicates that the change in the value of the factor causes a significant change in the response value, and on it, the same result for the regression contribution was obtained as the eml./ext. ratio, with a 95% confidence level, is still with the highest effect. p-value determines the importance of each factor (with a level of confidence 95%) where p-value >0.05 indicates that the influence of workers is not important for the model, and thus we conclude that the most important factor is the eml./ext. ratio. , while surfactant conc. is less important factor with p-value = 0.279 pundir et al. [26]. 5. conclusions successful recovery of cadmium ions from a hydrochloric aqueous solution was performed using elm technique. the results of improving study of changing the concentration of cadmium ions in the external stage were using elm technique with variation in process parameters in order to obtain the highest extraction efficiency (the minimum concentration of cadmium ions in the external stage). in this study eml./ext. ratio was found to be the dominant factor in extraction efficiency while the span 80 concentration was found to be the least influencing factor. optimal emulsion liquid membrane conditions were determined to maximize extraction efficiency (reduce the concentration of cadmium ions).they were ph = 3, surfactant conc. = 4%, carrier conc. = 8% emulsification speed = 19700 rpm and eml./ext. ratio = 18%. acknowledgment the authors wish to acknowledge the chemical engineering department /college of engineering / university of al-qadisiyah-for their support and assistance. references [1] w. kamiński and w. kwapiński, ‘applicability of liquid membranes in environmental protection’, polish j. environ. stud., vol. 9, no. 1, pp. 37–43, 2000. 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thermogavimertic behavior; tg curve introduction saccharum (sugarcane) is composed of 42% of cellulose, 25% hemicellulose and 20% lignin [1], hemicellulose consists of number of saccharides that be amorphous in their structure and rich in their branchs. a long unbranched glucose polymer refers to cellulose with a strong and ordered structure, in addition to have a high thermal stability. while an aromatic rings with many branches refers to lignin which may be degraded in a broad range of temperatures [2]. the degree of crystallinity of sugarcane fibers depends on the amount of hemicellulose and lignin so to increase crystalinity of sugar cane fibers it must be treated with alkali solution in order to dissolve hemicellulose and lignin leaving highly ordered chains of cellulose [3]. natural fibers have been used in a wide range to reinforce polymeric composites because of their eco-friendly nature. this present research aims to study the thermogravimeteric analysis unsaturated polyester composites reinforced with saccharum short fibers. the saccharum fibers were chemical treated with five concentrations of naoh (0.5, 1, 2 and 2.5 m) to investigate the effect of treated fibers on the thermal analysis of the prepared composites. 1. experimental part the used matrix system in the present study is the unsaturated polyester which representing thermosetting polymer. this polymer is thermosets type of polymers. to prepare polymer matrix, 2 gm of hardener was added to each 100 gm of unsaturated polyester. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 411 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. to prepare the composites, many steps were achieved for saccharum fibers including: collection, washing in distilled water and drying in an air oven for 10 h at 60oc. these fibers used as shortfibers with ≈ 1 cm in length. the chemical composition of this fiber was 45.5 cellulose, 27 hemicelluloses, 21.1 lignin, 4.6 extractives and 2.2 wt% ashes. chemical treatment of saccharum sodium hydroxide was used for chemical treatment with four weight percents include 0.5, 1, 2 and 2.5% at room temperature. the molarities of these solutions were prepared by dissolving certain weight of sodium hydroxide (m.wt. 40 gm/mol and purity 99%) in 100 ml of distilled water with volumetric flask. this treatment was achieved by immersion the short fibers in alkaline solution for 48 hrs. randomly oriented fibers were used to reinforce composites and added to matrix composite, and then very well mixed to maintain the uniformly distribution and finally poured in certain molds. cast iron molds with dimensions of (191×13×5 mm) and (80×10×5 mm). decreasing with vaseline was done for these molds were coated to avoid the adhesion of the prepared composites with inner surfaces and to easier removal of specimens. the prepared samples were left in the mould for (24) hrs. at room temperature for curing. thermogravimetric analysis (tga) was carried out at university of baghdad/college of education for pure science ibn al haitham by employing (sta pt 1000 linseis). the temperature range was from ambient temperature to 600oc at heating rate of 100oc/min under nitrogen stream. 2. results and discussion thermo gravimetric analysis (tga) is a useful analytical technique to assess thermal stability of materials including polymers by recording weight loss of a sample against temperature [4]. tga thermograms for prepared films are shown in figures (1) to (6). figure (1) shows the tga curve of pure unsaturated polyester, which indicates the two decomposition steps [5] that represent the scission of highly stained portion of crosslinked unsaturated polystyrene with followed free radicals that promote the final decomposition and scission of unsaturated polyester backbone [6]. the first occurs at the range of temperatures (230 – 355oc) with weight loss of 90% while the second step occurs at temperature range of (480 – 560 oc) with weight loss of 10% and that comes to 100% weight loss under the used temperature range. the reinforced unsaturated polyester composites with untreated and treated sacchraum fibers are shown in fig. (2) to (6). these figures show the two decomposition steps and they indicate that unsaturated polyester reinforced with untreated sugarcane and the alkali treated one with concentration of (2.5%) fibers enhance thermal stability comparing to the pure unsaturated polyester by shifting the temperature range of first decomposition step to a higher values, decreasing the weight loss occurred at first decomposition step and decreasing the total weight loss under the temperature range used. the unsaturated polyester reinforced with treated alkali solutions with concentrations of (0.5, 1, and 2%) never change greatly the weight loss at first and second decomposition steps comparing to pure unsaturated polyester. moreover total weight loss is still 100% but there are some changes in temperature ranges of both first and second decomposition steps. we see that the concentration of alkali (0.5%) shifts temperature ranges of first and second decomposition steps to a higher values comparing to pure unsaturated polyester .the unique behavior of unsaturated polyester reinforced with alkali treated sugarcane fibers of concentration (2.5%) comparing to other treated fibers is due to lignin dissolution in highly concentrated alkali al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 412 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. solution which increase crystallinity of saccharum fibers [7]. other data of thermal analysis of prepared composites are listed in table (1). conclusions the alkaline treatment of saccharum fibers to reinforce unsaturated polyester gave good incorporation of fibers in composites with slightly change of the thermal stability through the testing of thermogravimetric analysis (tga). references 1. misook kim • donal f. day "composition of sugar cane, energy cane, and sweet sorghum suitable for ethanol production at louisiana sugar mills"j ind microbiol biotechnol 2011,(33) no.7. 2. daniela a. mortari, marina c. britto, paula m. crnkovic," correlation between activation energy and thermal decomposition yield of sugar cane bagasse under co2/o2 and n2/o2",j.of chemical engineering transactions,2014 vol.37 pp (31-36) 3. a. a. guilherme1*, p. v. f. dantas1, e. s. santos1, f. a. n. fernandes2 and g. r. macedo1," evaluation of composition, characterization and enzymatic hydrolysis of pretreated sugar cane bagasse " brazilian journal of chemical engineering, vol. 32, no. 01, pp. 23 33, january march, 2015. 4. hatakeyama t.and quinn f.x. ,"thermal analysis fundamentals and applications to polymer science",second edition,jhon wiley and sons ,1999 5. j.m. ferreira,o.a.z.errajhi,m.o.w.richardson,"thermogravimetric analysis of aluminized e-glass fiber reinforced unsaturated polyester composite"polymer testing,vol,25,2006,2006,pp(1091-1094). 6. maria r ricciardi, vincenza antonucci, michele giordano and mauro zarrelli,"thermal decomposition and fire behavior of glass fiber– reinforced polyester resin composites containing phosphate-based fire-retardant additives" journal of fire sciences 30(4),pp. 318–330 7. kyaw wunna*,a, kiyohiko nakasakib, joseph l. aureseniaa, leonelia c. abellaa, pag-asa d. gaspilloa," effect of alkali pretreatment on removal of lignin from sugarcane bagasse",j.of chemical engineering transactions, vol. 56, 2017,pp.(1831-1836) al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 413 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table (1) data of tga thermograms for prepared composites reinforced with saccharum (sac.). sample step of decomposition temp. range (oc) weight loss (%) onset endset partial total pure polyester 1st 2nd 230 480 355 560 90.00 10.00 100 composite with untreated sac. 1st 2nd 270 480 365 560 86.00 9.18 95.23 composite with treated sac. in 0.5% 1st 2nd 280 500 375 550 92.00 8.00 100 composite with treated sac. in 1% 1st 2nd 230 470 360 550 91.00 9.00 100 composite with treated sac. in 2% 1st 2nd 220 500 360 540 88.00 12.00 100 composite with treated sac. in 2.5% 1st 2nd 250 500 360 560 83.23 13.52 96.75 fig. (1) tg curve of unsaturated polyester. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 414 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig. (2) tg curve of untreated saccharum/ unsaturated polyester composite. fig. (3) tg curve of treated saccharum (0.5%)/ unsaturated polyester composite. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 415 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig. (4) tg curve of treated saccharum (1%)/ unsaturated polyester composite. fig. (5) tg curve of treated saccharum (2%)/ unsaturated polyester composite. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 416 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig. (6) tg curve of treated saccharum (2.5%)/ unsaturated polyester composite article al-qadisiyah journal for engineering sciences 13 (2020) 175–182 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mushtaq76@gmail.com (mushtaq i. hasan) https://doi.org/10.30772/qjes.v13i3.704 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. improving the thermal performance of electrical transformers using hybrid mixture of (transformer oil, nanoparticles, and pcm) mushtaq i. hasan a*, adnan a. ugla a and hassan s. kadhim a a department of mechanical engineering, university of thi-qar, thi-qar, iraq. a r t i c l e i n f o article history: received 5 july 2020 received in revised form 31 july 2020 accepted 16 august 2020 keywords: nanofluid electrical transformer transformer oil cooling performance distribution transformer transformer cooling phase change material a b s t r a c t in this paper, an experimental electrical distribution transformer was studied and a new technique was proposed to improve the performance of a new mixed cooling consisting of pure transformer oil, paraffin wax and nanoparticles. the experiment was carried out on a small transformer that was done by taking a model with dimensions (15 * 10 * 10) cm to facilitate calculations. paraffin wax absorbs the heat generated in the transformer due to the smelting process that can be used to cool electrical appliances. nanoparticles have good thermal properties and lead to increased oil insulation to thermal improvements in transformer oil with dispersal of solid nanoparticles and their effects on transformer cooling. three types of solid nanoparticles were used in this experiment (al2o3, tio2, and sic) with a different volume concentration (1%, 3%, and 5%) and 4% paraffin wax as a certified added percentage for each process. the obtained results showed that when mixing paraffin wax and solid nanoparticles with transformer oil, the transformer cooling performance is improved by reducing the temperature. the best selected nanoparticles were found to be sic and the reason for this is that sic has a higher thermal conductivity compared to (al2o3 and tio2). the proposed hybrid oil reduces the temperature by 10 ° c (in the case of pcm and sic) and it is possible to improve the cooling performance of electrical transformers. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the transformer is a constant electrical device that transmits electrical energy between two circuits. the transformer consists of three main components: the primary winding which functions as the input, the secondary winding which acts as the output, and the iron core which enhances the produced magnetic field. nordman et al. [1]. a different current in one coil produces a heterogeneous magnetic flux, which in turn leads to a variety of wattages across the second coil around the same core. in 1831, faraday discovered the induction law that described the effect of induced voltage in any winding, due to the change in magnetic flux surrounding the winding bedell et al. [2]. several experiments had been carried out to improve the efficiency of electrical transformers and to observe their behavior; smith et al. [3]. comsol software was used to analyze numerically the dielectric changes and the resulting variable capacitance and dissipation parameters from moisture and temperature inputs. their findings suggest a deeper understanding of modeling and study of oip faults bushing. amit m., et al [4]. consider the insulation http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 176 mushtaq i. hasan, et al. /al-qadisiyah journal for engineering sciences 13 (2020) 175–182 system for the power adapter bushing. therefore, m4000 double capacity is used for the insulation analyzer. the bushings are represented as a critical element in the transmission of electricity. it is used in locomotives, transformers, and switches. bushings cause more than 15% of transformer failures. the main purpose of the sleeve was to convey the current load in and out of the metal (ground) packages at the system voltage. the breakdown of the insulation system caused a bushing malfunction in the tank rupture, fire, and explosion of the bushing. the obtained results showed how the dielectric and humidity properties change with the different power factor and capacitance of the insulation system. mushtaq i. [5]. a 250 kva transformer has been selected as a model to study the temperature range covering the hot weather. nanofluids based on transformer oil has been used as a refrigerant medium. four types of solid particles (cu, al2o3, tio2, and sic) were used with nanofluid (1%, 3%, 5%, 7%, and 9%). use the limited size method with a simple logarithm that was used to solve the problem of speed compression. the obtained results showed used nanofluids based on oil transformers a cooling medium leads to an increased in the cooling performance of the transformer by lowering the transformer temperature. the result of increased protection of the transformer parts. as a further step forward, in the same year, the same researcher mushtaq i. [6]. research published by the same work in the previous research. it used transformer oil that uses the existing mepcm suspension as a cooling medium in place of pure transformer oil. cooling oil for transformers consists of small capsules containing phase change substances called paraffin wax, surrounded a cap made of mixing polymers with pure transformer oil which results in a new mixture. contributes more than pure oil to cooling portions of the transformer. this way it will increase the transformer's cooling capacity. this also increased the life span of the transformer parts. the 250 kv transformer is designed with cfd, symbolized by the dimensions of real transformers. the small capsule contains paraffin wax as a pcm phase change material. which dissolves inside the capsule after absorbing the heat from the cooling oil. the capsules used were mixed with cooling oil at volume rates ranging from (5 to 25) percentage. from the results, he concludes a decrease in mixture temperature and internal parts of the mixture transformer. xiang z. et al. [7]. numerically studied a method for predicting flow distribution and pressure drop in forced oiland cooling-directed mode disk-type transformer windings. secondly, a dimensional analysis was conducted to determine independent variables in the winding that influence pressure drop and flow distribution. next, cfd was used to conduct parametric sweeps simulations under isothermal flow conditions. their results of flow distribution and pressure drop obtained from simulations were associated with variables that are not previously defined to derive correlation equations. these equations have been verified across a range of variables and applied to determine the inverse reversal criteria resulting. mushtaq i. and hind l [8]. studied the effect in the micro-channel heat sink materials change phase. air used in heat sinks for the first time and then used six pcm types (paraffin wax, n-eicosane, p116, and rt41). have been used as cooling mediums in different configurations and different arrangement of heat sink at different ambient temperatures. the results exposed that the cooling performance of micro heat sink enhances due to using phase change materials in the heat sink. in addition, they concluded that selected the phase change materials should according to their melt temperature. in addition, according to a certain application due to the difference in melting temperatures of pcms. the cost of materials used depends on the types of the pcms (organic and inorganic), and the quantity of pcms used in the application. as a further, step forward, in the same year, the same researchers mushtaq i. and hind l. [9]. published research in the same procedures and action steps as in the previous research. however, using two types of pcms (n-octadecane and rt44) and heat flux applied on the base of the heat sink is 640 w/m2. the heat sink was used with unfanned and with three types of fins (square, triangular, and circular). their results presented that, used the pcms lead to improvement of the cooling enchantment of micro heat sink. in addition, values of heat reduction sink different according to different phase change materials used in a range of ambient temperature due to the difference in its melting temperatures. mushtaq i. and alaa a. [10] presented a report on a transformer for electrical diffusion. it was tentatively concentrated, and a novel technique was suggested to improve its cooling efficiency by extending paraffin wax to transformer oil using aluminum shut-oil holders. those compartments in the transformer oil were drenched. a 100-kva transformer was used as a model for research on the grounds that typically such transformers are used in the power appropriation scheme in iraq. the stage wax (paraffin wax) changes material as temperature rises assimilates warmth and melts inside the holders at a steady temperature. this element can be used to store heat for a period until the temperature for climate drops; at that point, this warmth is dismissed, and the wax starts to cement. right now, holders were utilized, each containing 2 kg of wax. the outcomes indicated an away from in the temperature of the oil, which prompted the enhancement of its warm protection and kept the oil from disappointment and safeguarded the transformer from breakdown. the outcomes demonstrated that the decrease in temperature is around 7°c and the decrease expanded after expanding the measure of wax included. in this paper, a proposed new technique will be used to improve the thermal performance of electrical transformers using a hybrid mixture of pure transformer oil and paraffin wax and nanoparticles inside the transformer where paraffin wax absorbs the heat generated in the nomenclature a area (m2) h latent heat (j/kg) cp specific heat (j/(kg·k)) m mass (kg) cpl specific heat of liquid (j/(kg·k)) q heat stored (j) cps specific heat of solid (j/(kg·k)) v volume (m3) k thermal conductivity (w/m·k) kl thermal conductivity at liquid state (w/m·k) ks thermal conductivity at solid state (w/m·k) t temperature (k) μ dynamic viscosity (kg/m·s) tl temperature of liquidity (k) tes thermal energy storage tpc phase change temperature (k) pcm phase change material ts temperature of solidity (k) ρ density (kg/m3) mushtaq i. hasan, et al./al-qadisiyah journal for engineering sciences 13 (2020) 175–182 177 transformer due to the melting process. the nanoparticles have good thermal properties and lead to increased oil insulation thus, this hybrid mixture absorbs the heat generated from the coils and pulp and keeps the transformer from collapsing. 2. materials and methods the experimental research and equipment used in the present analysis were based on a miniature model according to the standard (iec60076) the electrical transformers. the experiment was done on a 100(kva) mini transformer. this was done by taking a model with dimensions (15*10* 10) cm by scaling all dimensions of transformer oil in one scaling factor to facilitate the calculations. the studied transformer is compound of the following parts: aoil tank: it is a tank made of hot rolled iron sheets formed according to the types of transformers and painted from the outside to prevent the arrival of moisture and not being affected by the external air conditions. heat exchange between the transformer and the outer circumference as it is in the original transformer. bthe electric heater: it is a small electric heater with a capacity of 60 watts and it is immersed in the oil tank. cooling the transformers and it is used as a source of heat and its ability is controlled through the power regulator device it is used to simulate the heat generated from coils during real operation. cpower regulator: it is a 4000 watt regulator that is connected between the electric heater and the electric power source, in addition to connecting each of the voltmeter and meter devices to control the current and voltage to obtain the required amount of heat. d-thermo-meter temperature recorder: it is an electronic device that is reliable in this experiment and contains twelve channels to record the temperature (model: btm-4208sd), its accuracy, (±0.4%+1ₒc) and the range (+999.9ₒc to 50) measuring the temperatures inside the transformer and outside. e-thermocouple: consist mainly of two part of semiconductors or dissimilar conductors. this part contraction each other at a connection and a voltage difference is formed when they inversely expand under the same temperature. the thermocouples used had a small wire diameter of 0.21 mm and a type k probe. heat sensors were distributed inside the transformer a way to ensure that the average transformer oil temperature is obtained. 3. experimental procedure 1the transformer tank was filled with pure transformer oil of 1.5 liters and the electric heater was dipped inside the tank that is filled with transformer cooling oil and a data logger was attached to 12 temperature sensors as the first sensor is used to measure the ambient temperature, while the remaining eleven sensors they were distributed in order across the transformer, where 5 sensors were immersed at a height of 2 cm from the bottom surface of the transformer. as for the rest of the sensors, they were distributed at a height of 4 cm from the bottom surface of the transformer and different locations. the heater was equipped with an electric power of 60 watts through the power regulator. 2this experiment was conducted in february as the transformer was placed in a closed room with heat sources on it the purpose is to raise the room temperature above 50 ° c. the reason for this is that the experiment was carried out in the winter season and we cannot get a temperature of 50 ° c or less. 3 the readings were taken for about four hours in the case of high temperatures and the case of decline. paraffin wax and nanoparticles were added with the same amount of energy as the electric heat and for the same time where 4 percent of paraffin wax was mixed and the ratio approved in this experiment with each of the metal nanoparticles, which includes both al2o3, tio2, sic (1 %, 3 %, 5 %) where it has been observed that when the wax is added by 4 percent to the three percentages for each substance, there is a decrease in temperature, especially when the percentage of sic is increased and this is due to the high conductivity that sic possesses compared to (al2o3, tio2) where the process of adding each of the solid nanoparticles (tio2, al2o3, sic) in ratios (1%, 3% and 5%) for each substance to the pure transformer oil at a weight of 1.5 kg. 4 the sic substance was taken at 1% of the weight of the pure oil and mixed it with pure oil and the same process for the remaining ratios of tio2 as well as the same process for the two materials (al2o3, tio2). this process was performed in a basin containing an electric fan. as shown in fig. 1. 5the process of dissolving the wax was done by heating it in a container as shown in fig. 2. as well as for the mixture consisting of pure oil and nanoparticle solid particles, from which the added wax proportions will be added to it as shown in fig. 3. table 1 shows the thermal properties of transformer oil and nanomaterials used in the experiment as well as paraffin wax. figure 1. shows the process of mixing sic with pure oil. 178 mushtaq i. hasan, et al. /al-qadisiyah journal for engineering sciences 13 (2020) 175–182 figure 2. melting wax and preparing it for mixing. figure 3. the stages of filling the tank with a mixture of transformer oil, paraffin wax and mineral particles table 1. thermo physical properties of the materials that used [12][13][14] anthulaby of fusion kj / kg specific heat cp (kj / kg. k) viscosity dynamic 𝜇 (kg / ms) coefficient of thermal conductivity k (w / m .oc) density 𝜌 (g/m3) type of material 0 0.0124 2 0.109 880 transformer oil 1 179.6 0.0063 solid state cps = 3.2 and liquid state cpl = 8.1 solid state= 215 and the liquid state = 12 773 paraffin wax 2 686.2 8.953 4250 tio2 3 765 36 3600 al2o3 4 775 490 3160 sic 5 the electric heater is a small electric heater with a capacity of 60 watts and it is immersed in the oil tank. cooling the transformers is used as a heat source and controlled by the power regulator device fig. 4 and the electric heater was used to replace the electrical coils as shown in fig. 5. figure 4. power regulator figure 5. electric heater the temperatures were measured by thermal pairs and as shown in fig. 6 and recorded using a data logger which contains 12 sensors as shown in fig. 7 and fig. 8 which shows the assembly and connection of the parts used in the experiment. figure 6. thermocouples type k mushtaq i. hasan, et al./al-qadisiyah journal for engineering sciences 13 (2020) 175–182 179 figure 7. temperature measuring device used in the experiment figure 8. the assembly and connection of the parts used in the experiment 4. results and discussion fig. 9 show the variable in mean temperature of the transformer with time of the coolants (pure transformed oil, transformed oil pcm suspension, tio2 nanofluid oil suspension and hybrid suspension). it can be seen from the figure that the amount of latent heat absorbed by the pcms for each pcms to use increases with the increase in the ambient temperature due to the increase in the smelting portion as well as the increased heat absorbed with the increase in the amount of pcms to use. this is normal, because the increase in the amount of pcms means an increase in the average heat storage to an increase in the volume of latent heat taken up by the oil. in addition, tio2 nanofluid has been used in different concentrations, which in turn reduces the transformer temperature due to thermal conductivity, which leads to improved heat transfered process by enhancing the thermal conductivity of the oil by dispersing nanoparticles and the thermal conductivity with a rise in the tio2 nanofluid volume portion. fig. 10 shows the variation in mean temperature of the transformer with time to the pure transformer oil, the transformed oils pcm suspension and al2o3 nanofluid oil suspension and hybrid suspension. from this figure it can be observed that when using wax with al2o3 nanofluid leads to a decrease in temperature which is due to this because paraffin wax has a high ability to store heat by absorbing it in the form of latent heat. it also increases the decrease in the temperature of the transformer when adding al2o3 nanofluid, because of the high thermal conductivity of us leads to an increase in the rate of heat transfer and thus the heat is removed from the transformer and protected from failure. fig. 11 shows the variable in the average temperature of the transformer with the time of the different coolants (pure transformer oil, transformed oils pcm suspension and sic nanofluid oil suspension and hybrid suspension). from this figure, it can be seen that there is a clear decreased in the temperature of the transformer when using paraffin wax oil and nanofluids. the reason for this is that paraffin wax absorbs the heat generated in the transformer and thus works to protect the transformer from damage by increasing its cooling efficiency. added to sic nanofluid with a higher thermal conductivity compared to which leads to an increase in the method of heat transfer by enhancing the thermal conductivity of the oil by dispersing the nanoparticles and increasing the thermal conductivity by increasing the size of the sic nanofluid. fig. 12 show the variable in the average temperature the hybrid mixture consists of a mixture of wax and nanoparticles of 5% for each substance that increases with an increase in the external temperature. for all cases, when the external temperature is 52oc, we notice that the oil temperature is 88 0c, and when adding 4% of wax with 5% of tio2 nanofluid, the temperature of the transformer decreases to 84 oc, and when adding the same ratio of paraffin wax with 5% of al2o3 nanofluid increases temperature decreases to 80 ° c and when adding the same percentage with paraffin wax with 5% of al2o3 nanofluid increases more to 77oc so that sic nanofluid gives average lower temperature compared to other selected nanomaterials within the specified temperature range external. fig. 13 shows a reduction in temperature over time between pure transformer oil and transformer oil pcm suspension at 4% and nanofluid oil suspension at 1%. this figure it can be observed that when using a pcm suspension with tio2 nanofluid, and at external temperatures 52 on specifically, after two hours, we notice that the amount of decrease in the temperature of the transformer is 3.6 ° c. as for al2o3 nanofluid, the amount of decrease is 5.5 ° c and for sic nanofluid, the amount of temperature drop is 6.5 ° c. from this figure, we find that the decrease will increase when using sic nanofluid due to the improvement of the thermal conductivity of the oil and consequently an increase in the heat transfer rate. fig. 14 shows a reduction in transformer temperature over time between pure transformer oil, paraffin wax at 4%, and nanofluid oil suspension at 3%. at an external temperature of 52 ° c and after two hours and under thermal generation, which is 60 watts. it can be observed that when using a pcm suspension with tio2 nanofluid oil suspension, the amount of drop in the transformer temperatures is 5.8 ° c, while for al2o3 nanofluid, the amount of drop is 6.8 ° c. as for sic nanofluid, the amount of decrease in temperature is 7.8 ° c. from this figure, we find that the decrease will increase when using sic nanofluid. because of the improved thermal conductivity of the oil and thus the increased rate of heat transfer and thus kept the transformer from collapsing and failing at to the temperatures that transformers in hot regions and at overload encounter it. fig. 15 shows a reduction in the transformer temperature with the time between pure transformer oil, paraffin wax at 4%, and sic nanofluids oil suspension at 5%. this decrease in temperature has differed greatly from the previous two forms because the sic of nanofluid increased significantly. because it is known when increasing sic nanofluid thus leads to an increase in thermal conductivity, especially when using sic nanofluid and in the case of high external temperatures to compared with other selected nanofluid over the selected range of outside temperature 52 ° c where the amount of the decrease in temperatures reached 9.9 ° c in the peak period and thus this hybrid oil contributes to increasing the efficiency of the performance of the transformer from by reducing the temperature of the cooling oil and thus extending the life of all the transformed parts and increasing 180 mushtaq i. hasan, et al. /al-qadisiyah journal for engineering sciences 13 (2020) 175–182 transformers efficiencies and preservation from collapse and explosion, which leads to environmental conservation. fig. 16 shows the variation of temperatures with the weight proportions of the solid nanoparticles with adding 4% wax material for all cases where when adding 1% of titanium oxide with wax, the temperature is 54oc and the same percentage when adding aluminum oxide, the temperature is 50oc and the same percentage for silicon carbide, 49oc. when adding 3% of titanium oxide, the temperature is 530c and the same percentage. when adding aluminum oxide, the temperature is 48 0c, and the same percentage when adding silicon carbide, the temperature is 46oc. when adding 5% of titanium oxide, the temperature is 51 0c. moreover, when adding the same percentage to aluminum oxide, the temperature is 45oc, and when adding the same percentage to silicon carbide, the temperature is 42°c. we conclude from this that there is a significant decrease in temperature, especially when using silicon carbide due to the high thermal conductivity that this substance possesses compared to other materials (titanium oxide and silicon oxide) so this method can be used to protect the transformer from damage by increasing the efficiency of cooling. the figure also shows that the temperature decreases by increasing the proportion of added nanoparticles due to the further improvement of the heat transfer due to the increase in the thermal conductivity. figure 9. the variation of fluid temperature with time when using pure oil, as well as adding 4% of the wax and the mixture consisting of 4% of the wax and tio2 with different ratio figure 10. temperature variation in the transformer with time when using pure oil, as well as adding 4% of wax and the mixture consisting of 4% of wax and al2o3 with different ratio figure 11. the variation of temperatures inside the transformer with time when using pure oil, as well as adding 4% of the wax and the mixture consisting of 4% of pcm suspension and sic-oil nanofluid suspension in different ratio a. (from 26 to 52 oc) 25 35 45 55 65 75 85 95 25 30 35 40 45 50 55 t e m p e r a t u r e )o c ) outside temperature(oc) 0.4wax,0.5 al2o3-oil suspension 0.4 wax ,0.5 tio2-oil suspension 0.4 wax , 0.5 sic-oil suspension pure oil 30 40 50 60 70 80 90 0 100 200 300 t e m p e r a t u r e (o c ( time(min( 4% wax ,1% sic-oil suspension 4% wax,3% sic-oilsuspension 4% wax , 5% sic-oil suspension pure oil 0.4 wax 20 30 40 50 60 70 80 90 20304050 30 50 70 90 0 100 200 300 t e m p e r a t u r e (o c ) time(min) 4% wax,1% tio2-oil suspension 4% wax, 3% tio2-oil suspension 4%wax ,5% tio2-oil suspension pure oil 30 40 50 60 70 80 90 0 100 200 300 t e m p e ra tu re (o c ) time(min) 4%wax,1% al2o3-oilsuspension 4% wax,3% al2o3-oil suspension 4% wax,5% al2o3-oilsuspension pure oil 0.4 wax mushtaq i. hasan, et al./al-qadisiyah journal for engineering sciences 13 (2020) 175–182 181 b. (from 52 to 26 oc) figure 12. variation of the average fluid temperature with outside temperature presence of paraffin wax and the four transformed types with the external temperature with nanofluids figure 13. the reduction with time between the fluid temperature formed by each type of nanoparticle at 1% which contains 4% of pcm and the temperature of pure figure 14. the reduction with time between the fluid temperature formed by each type of nanoparticle at 3% which contains 4% of pcm and the temperature of pure figure 15. the reduction with time between the fluid temperature formed by each type of nanoparticle at 5% which contains 4% of pcm and the temperature figure 16. the variation of fluid temperature with the volumetric ratio of the nanafluids and paraffin wax 3 3.5 4 4.5 5 5.5 6 6.5 7 0 100 200 300 r e d u c ti o n (o c ) time(min) for 4%, 1% sic oil nanofluid for 4% wax,1% al2o3 oil nanofluid for 4% wax,1% tio2oil nanofluid 5 5.5 6 6.5 7 7.5 8 8.5 0 100 200 300 r e d u c ti o n (o c ) time(min) reduction 0.4 wax,3% sic oil suspension reduction 0.4 wax,3% al2o3 oil suspension reduction 4% wax,3% tio2 oil suspension 4 5 6 7 8 9 10 11 0 100 200 300 r e d u c ti o n (o c ) time(min) reduction 4%wax.5% tio2 -oil suspension reduction 4% wax,5% al2o3 oil suspension reduction 4% wax,5% sic oil suspension 42 44 46 48 50 52 54 56 0 1 2 3 4 t e m p e r a t u r e (o c ) volumetric concentration(c%) 4% wax,sic oil suspension 4% wax , tio2 -oil suspension 4% wax, al2o3oil suspension 182 mushtaq i. hasan, et al. /al-qadisiyah journal for engineering sciences 13 (2020) 175–182 4. conclusions in this paper, paraffin wax with nanoparticles and mixed with oil. this hybrid suspension has been experimentally studied. different types of nanoparticles (tio2, sic, al2o3) are chosen at different ambient temperatures with different mixing concentration and masses. from the results obtained, the following concluding comments may be adopted: 1using the oil with wax and nanoparticles leads to improved cooling of the electrical transformer parts. when the external temperature is 52°c, the pure oil temperature is 87°c. when adding paraffin wax with tio2-oil, we notice a decrease in temperatures to reach 84°c for pure oil. as for adding wax with al2o3-oil, there is a decrease in temperatures of up to 80 0c. as for adding paraffin wax with sic-oil, we notice a significant decrease in temperatures of up to 10 oc to reach 77°c because silicon carbide possesses high thermal conductivity compared to other fluids used in this experiment. 2temperature of the transformer that may exceed the acceptable limits. the transformer has been subjected to the conditions of collapse and the new mixed oil is very useful for hot areas and peak times and a network with large loads and high consumption as the cooling efficiency increases with increasing air temperature. 3wax works to protect the transformers against collapse at high air temperature during peak periods. since it merges, the temperature varies from 50 to 57oc. 4the reduction temperature of the transformer depends on the mass fraction of the volume at which all the nanoparticles and paraffin wax mix with the oil. the reduction in temperature increases with the increase in the volume of the paraffin wax volume and the nanofluids. in addition, among all the studied particles, the sic-oil gives a lower temperature for transformers followed by nanofluids with al2o3 oil, etc. 5the main purpose of this experiment is to find a new oil that contributes to increasing the cooling efficiency of transformer performance by reducing its temperature of the cooling oil, prolonging the service life of all parts of the transformer, increasing transformer efficiencies, and preserving them from collapse and explosion, which leads to maintaining an environment that save cost through maintaining transformers and protecting them from the explosion of a huge number of transformers which work in distribution networks. references [1] nordman h., rafsback n., and susa d., "temperature responses to step changes in the load current of power transformers", ieee transactions on power deliver vol. 18, no. 4 , pp.1110 1117, 2003. 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"improving the cooling performance of electrical distribution transformer using transformer oil–based mepcm suspension." engineering science and technology, an international journal, vol.20, no.2, pp. 502-510, 2017. [7] xiang z., zhongdong w., and qiang l., “prediction of pressure drop and flow distribution in disc-type transformer windings in an od cooling mode” , ieee transactions on power delivery, vol. 32, no. 4, pp. 16551664, 2017. [8] mushtaq i. hasan and hind l. tbena., "using of phase change materials to enhance the thermal performance of micro channel heat sink", engineering science and technology, an international journal, no. 21, pp. 517-526, 2018. [9] mushtaq i. hasan and hind l. tbena., "enhancing the cooling performance of micro pin fin heat sink by using the phase change materials with different configurations." advance of sustainable engineering and it’s application (icasea), 2018 international conference on ieee, pp. 205-209, 2018. [10] mushtaq ismael hasan, alaa abdlullah abduladheem" modifying the thermal performance of electrical distribution transformers using phase change materials (paraffin wax) " heat transfer—asian res. 2019;48:2440‐2455. [11] oró e, degracia a, castell a, farid mm, cabeza lf. review on phase change materials (pcms) for coldthermal energy storage applications. apple energy. 2012;99:513‐533. [12] mostafa k. m., reza m. a., ali i., “cfd investigation of nanofl uid effects (cooling performance and pressure drop) in mini-channel heat sink”, international communica tions in heat and mass transfer, 40, pp. 58-66, 2013. [13] eiyad a.n., “application of nanofluids for heat transfer enhancement of separated flows encountered in a backward facing step”, int. j. heat and fluid flow 29, pp. 242-249, 2008. article al-qadisiyah journal for engineering sciences 13 (2020) 158–166 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964 7814136944 e-mail address: mohamed.aldawody@qu.edu.iq (mohamed al-dawody) https://doi.org/10.30772/qjes.v13i2.664 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. biodiesel production from spirulina microalgae and its impact on diesel engine characteristics-review mariam emad murad a, mohamed f. al-dawody a* a department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq a r t i c l e i n f o article history: received received in revised form accepted keywords: microalgae oil ame production biodiesel properties engine performance emissions characteristics a b s t r a c t this research aims to investigate the literature review on the extraction of algae oil, production of algae methyl ester (ame) biodiesel and the effect of microalgae biodiesel on the performance, combustion and exhaust emissions of diesel engine. the study dealt with researchers who published their reports between 2006 and 2020. researches now concentrate on renewable energy, and biodiesel is one of the renewable energy sources. biodiesel is a fuel similar to diesel and has many positive aspects such as quality, renewable energy, lower exhaust emissions, and greater lubricity. in addition to the use of microalgae in the production of fuels, they are used in reducing co2 of the atmosphere which in turn results in better air quality to breathe and cleaner environment. many researchers have paid attention to produce biodiesel derived from microalgae that represents one of the oldest living creatures on the globe. however, by comparing it with diesel, it has some drawbacks like lower heat content, higher density, viscosity, and nox emissions. optimization strategies are still recommended to fight the side effects of using biodiesel instead of original diesel fuel. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction for more than a century, the diesel engine engines have deep impact on the industrial economy, as they are used in a wide variety of applications that require mechanical motive power. increasing tough emissions regulations coupled with fast depleting crude oil resources have caused a stimulation of interest in finding alternative fuels for petroleumbased fuels like diesel and gasoline [1]. extracting oil from plant resources has attracted considerable attention. in many countries, vegetable oils are used after esterification as "biodiesel" [2]. researchers have turned their interest towards fuel production from one of the oldest living creatures on the earth, microalgae. besides their use of producing fuels, also for capturing the co2 from the environment which gives better air quality to breathe. algae are one of the most exciting future solutions for our energy crisis, especially that of transportation fuel. algae need very low requirements to grow including carbon dioxide, sunlight, and water [3]. the objective of the present article is to conduct a comprehensive review starts from the oil extraction process, converting the extracted oil to biofuel and ends with the impact of using it as a fuel blended with diesel fuel on the performance, emissions, and combustion parameters of diesel engine. 2. extraction algae oil the oil extraction refers to an operation that transfers one or more components of a solid or liquid phase to another liquid phase. several methods are used to extract the oil from microalgae, such as mechanical extraction and chemical extraction. solvent extraction process is more common than mechanical as it extracts almost all the oil and leaves in the http://qu.edu.iq/ mailto:mohamed.aldawody@qu.edu.iq https://doi.org/10.30772/qjes.v13i mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 159 raw material just (0.50.7) percent of residual oil. the solvent extraction process can apply to any raw oil content materials [4]. the next lines summarize the recent literature papers that deal with the extraction process. baig et al. [5] explained the oil extraction process from microalgae spirogyra biomass by using n-hexane as a solvent. the authors studied and analyzed the effect of contact time, size of algal biomass, n-hexane to oil proportion on the percent yield of oil extraction. it was noted that the maximum volume of oil was derived from the biomass of spirogyra using longer contact time, the smaller size of algal biomass, and a greater proportion of solvent to algal biomass. the study registered a 2.5-fold rise in the algae-to-solvent ratios from 1:1 to 1:3 compared with the previous ratio. topare et al. [4] experimentally studied several methods of oil extraction from algae growing in the open pond system, such as hexane solvent extraction, mechanical pressing, etc. it was noted that the solvent method recovers nearly all the algae oil and leaves only 0.5% to 0.7% oil remaining in the material raw. solvent extraction method was found to be a better method for the extraction of fats and oils, due to the higher percentage of oil recovered. the study pointed out that the expeller method could recover 75% of the oil from the microalgae. shimi et al. [6] described in detail the chemical extraction of algae oil from platensis-spirulina using several different solvents subjected to different conditions. the results showed that soxhlet extraction using methanol gives the highest rate of algae oil extraction (98.5%) at 1 hour using biomass to solvent ratio of (1:110). specifications of oil extracted, showed that viscosity is 58 mpa.s, density is 0.89 kg/l and the acid number is 37.4 mg koh/g, because of these high values, the algae oil should be transformed to biodiesel by using the appreciated methodology. it was concluded that biodiesel derived from algae oil appears to be golden substitute fuel to reduce the dependence on petroleum fuels. the fatty acid in spirulina is palmitic acid (48.35%) makes it a promising feedstock for the production of biodiesel. a simple, friendly and energy-efficient method of extraction crude oil from microalgae utilizing dimethyl ether (dme) was presented by kanda and li. [7]. the authors tested this method on some kinds of natural microalgae (green-blue). as a result, green crude was effectively straight extracted from elevated moisturemicroalgae (78.2–93.4 %water content), with an extraction rate changing from (9.9 to 40.1 % dry weight) of the microalgae. the yield extracted by liquefied (dme) was contrasted with the bligh-dyer process widely used. the dme technique nearly attained efficient extraction similar to the bligh-dyer’s method. it was also found that traditional methods are unable to remove green crude directly from elevated moisture microalgae. a detailed description of the optimum conditions of the extraction oil method from microalgaechlorella was presented by abdullah et al. [8]. soxhlet extraction method is used. it was found that the greatest extraction rate is 61.27% when using heptane as a solvent in the following conditions: 65 °c temperature of reaction, mixing rate of 600 rpm, and extraction time of 5 hours. yoo et al. [9] applied directly osmotic shock way to wet microalgae biomass with more 99% water content for the extraction of lipids, with both polar and non-polar organic solvents. the results indicated that osmotic shock increases lipid recovery nearly 2 times, and advised that it is a good technique to remove wet lipid from biomass of microalgae. shah et al. [10] discussed the production of oil economics from the algae grown in open ponds by ultrasonic wave, soxhlet and expeller method. about 50% of algae oil was converted to biodiesel by using the transesterification process. the results highlighted that the soxhlet method was the most reliable method for oil extraction. shin et al. [11] investigated the performance, economic hurdles, special features of different methods to produce microalgae mass involving open pond, photo bioreactor, and immobilized culture procedures. the system of open ponds was considered the easiest, simplest, and least costly method. despite this, their productivity is poor and easily infected with other microorganisms. the other widely used algal culture systems are the photo bioreactors. it can achieve double biomass efficiency as compared to open ponds along with greater control of pollution with complex designs of gas transfer, light dilution, and thermal insulation. immobilized algae cultivation systems have huge potential to reduce the harvesting issue of open ponds and photo bioreactors and increase the productivity of biomass. wiyarone et al. [12] described the characteristics of microalgae oil extracted from nannochloropsis sp. two extraction processes were examined, soxhlet-assisted and ultrasonic-assisted. both methods used ethanol as a solvent. the outcomes revealed that the concentration of ethanol influenced the quality of the algae oil. the better outcome achieved when the concentration of ethanol was 70%. in the meantime, the amount of circulation also affects oil yield quality. the optimum time was 200 minutes. while the use of ultrasonic extraction significantly reduced the temperature and time. the gcms test of algae oil components indicated that there was no noticeable difference between the two extraction methods is recorded. halim et al [13] used the supercritical carbon dioxide (scco2) and hexane method for the extraction of the lipids from marine chlorococcum. various variables affect the efficiency of scco2 extraction, such as extraction time, type of algae used, temperature, and pressure. compared to other lipid-rich microalgae organisms, the chlorococcus used in this study was calculated to have a relatively low lipid yield (7.1 % of dry biomass). the findings showed for scco2 extraction, decreasing temperature and increasing pressure resulted in increased lipid yields. the extraction of soxhlets using hexane is significantly less effective than the extraction of scco2, resulting in a comparable lipid yield (0.058 gram of lipid extracted per gram of dried microalgae). table 1 listed the researcher's findings in a summarized way. 3. production of ame biodiesel with the ever-increasing demand for energy and impending depletion of fossil fuels, it has become necessary to find out sustainable source of energy. promising alternatives closer to conventional diesel fuel include algae biofuels, particularly algae biodiesel have been used successfully powered diesel engines. one of the most popular methods used for the production of biodiesel is the transesterification process. the methanol along with sodium hydroxide as the base catalyst used to minimize the raw oil's free fatty acid content the specific parameters that influence the transesterification reaction are: the molar ratio of oil to methanol, the concentration of the catalyst, reaction temperature and time. the next coming studies related to the production of algae methyl ester (ame) biodiesel via transesterification process. karmakar et al. [14] described the preparation of biodiesel from unused algae in two step procedure, acid esterification followed by transesterification. taguchi’s method was utilized to design the experiment. the best operating conditions for transesterification were selected at (methanol/oil) molar ratio of 6:1, 2.5wt% catalyst koh,50 °c temperature, and 90 min of reaction time, getting 89.7% of a biodiesel 160 mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 production with 0.25% of content free fatty acid. it was found that diesel engines released less hydrocarbon, co, co2, and higher nox when using algal biodiesel instead of using petro-diesel. all properties of the produced biodiesel obtained were meeting astm standards. lardon et al. [15] provided an overview of the possible environmental effects of micro-algae biodiesel production. a virtual facility comparative life cycle assessment analysis was undertaken to assess the energy balance and possible environmental impacts of the entire process started from the processing of biomass up to the combustion of biodiesel as shown in figure (1). the results confirmed the ability of using microalgae as an energy source, but emphasize the imperative need to reduce energy consumption and fertilizer use. the regulation of nitrogen stress during cultivation and the optimization of wet extraction seemed to be useful options. figure (1) schematic diagram for the production and testing of ame biodiesel sánchez et al. [16] examined the effect of added n-hexane on the transesterification of solid raw materials for the production of biodiesel. algae oil extraction and reaction were performed concurrently in a batch reactor, incorporating n-hexane with the reactants. the findings revealed that n-hexane has no major effect on the transesterification process. it has been noted that this method requires large amounts of methanol to perform the reaction. the reaction requirements for marine macro-algae transesterification were methanol/oil molar ratio (300:1), 60°c temperature, and around 11 hours reaction time. this resulted in a yield of 17.1 % methyl esters. miao et al. [17] developed a coordinate strategy to produce the biodiesel from heterotrophic microalgae oil. with the use of n-hexane, large amounts of microalgae oil were effectively extracted from heterotrophic cells. the best procedure of mixing was 100% catalyst amount, methanol to oil 56:1 molar ratio at a temperature of 30°c in around 4 hours response time, which reduced specific gravity from 0.912 to 0.8637. the outcome indicated that the new technique, which incorporated transesterification and bioengineering, was a feasible and efficient approach for producing high-quality microalgae oil biodiesel. scott et al. [18] designed an overview of the potential algal biofuel pipeline and focused on previous researches aimed to improve the production of algal biomass and the fuel molecules contained within the algal cell. figure (2) shows an approach for algal biodiesel development. several factors need to be considered and optimized at each point, including inputs of energy and materials (e.g. nutrients and energy for mixing during growth). figure (2) algal biofuel pipeline hariram, et al. [19] derived algae oil methyl ester(aome), from spirulina microalgae grown in a photo bioreactor. a two-step solvent extraction method employing ether and hexane solvent was applied to obtain the algae oil. cyclohexane was put into biomass to eliminate the residual algal oil. the percentage of algal oil was obtained in this method is 92%. the transesterification method was applied to produce algal oil methyl ester by adding methanol and sodium hydroxide. the aome was mixed with diesel at different blending ratios (5%, 10%, and 15%). it was noted that co, hc, smoke, and particulates emissions decreased while a slight increase in the nox emissions is reported. recently microalgae have achieved much interest because of their high oil contents and rapid growing rate. tüccar and aydın [20] focused on microalgae biodiesel as an alternative fuel in diesel engines. biodiesel production of microalgae oil was mixed with diesel at (5%, 10%, 20%, and 50%) blending ratio. the results displayed a reduction in brake power and torque values of the engine when using microalgae biodiesel while the emission values were reduced. kammakar et al. [21] studied the production of biodiesel from microalgae oil by transesterification reaction. methanol is used along with koh as the catalyst. they found that perfect conditions for obtaining minimum viscosity and free fatty acid content with maximum ester when using oil to methanol 1:6 molar ratio, 3 wt% of koh, 1 hour time, temperature of 60 °c and 2.5 hours of settling time. most significant properties of ester biodiesel like fire and flash point (158 and 153 °c), viscosity (3.12 mm2/s), carbon residue content (0.03%), pour and cloud point (−6 and −1 °c, respectively) were found within the range of astm/bis standards. akubude et al. [22] worked on the production of biodiesel from microalgae via. transesterification process. the authors studied the mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 161 production of microalgae, economic purposes of microalgae involving production of the fuel, food product extraction, co2 capture for bio refinery resulting in the production of bio hydrogen, bio methane, and bioethanol. issues included various groups of catalysts such as heterogeneous catalysts, homogenous catalysts, and enzymatic catalysts. the use of this technology for the production of biofuels can be commercialized for developing the biodiesel industry. gradual rise in carbon dioxide co2 concentrations in the atmosphere because of the many anthropogenic activities resulting in major changes in the global carbon cycle. therefore, microalgae appeared to be an effective medium for capturing extra co2 existing in the atmosphere produced from various sources, like automobiles, power plants, and forest fires. capturing co2 through microalgae used as a significant source of carbon to produce lipids from biofuel to replace fossil fuel-derived transportation fuel without influencing crop and food supplies. various parameters such as time, temperature, light intensity, co2 concentration, ph, and flow rate were discussed as a factor affecting on production of biodiesel in photo bioreactors. the results showed that using this method can reduce the proportion of co2 in the atmosphere, and thus reduce global warming ( mondal et al. [23]). ahmed et al. [24] collected the algae spirogyra spices from various regions of pakistan and utilized it as a feedstock for production the biodiesel in two stages. during the first stage, the oil was extracted from algae using di-ethyl ether and n-hexane as solvents, while in the second step, extracted oil was converted to biodiesel through transesterification process. almost 95% of biodiesel was obtained using catalyst (sodium hydroxide) amount of 0.5wt%, contact time of 25 min at 60 °c and 1:8 molar ratio of oil/methanol. fulke et al. [25] explained a feasible technology to convert microalgae lipids lived in a wastewater pond to biodiesel by using photosynthetic co2. the highest co2 fixation rate was observed in mixed algae samples, followed by chlorella. these findings indicated that biodiesel produced from microalgae lipids can indeed prove profitable, if grown under suitable nutrient and co2 conditions, will lead to an ideal high biodiesel yielding cycle and effective sequestration of co2. aljabarin et al. [26] studied the production of biodiesel from algae. the algae were taken from open ponds and then dried for 12 hours in the oven at 80 °c. powder was gained by using a disc mill to grind the dried algae. iron sulphate hydrate is added to the powder to obtain algae oil utilizing a distillation column. methanol and potassium hydroxide as a catalyst were added to algae oil, the mixture then put in a separated funnel for around 10 hours until two layers of the mixture were obtained, the upper layer represents the biodiesel as shown in figure (3). the outcomes highlighted that biodiesel properties are similar to diesel, except that it decreases carbon dioxide co2 emissions and sulfur dioxide so2 emissions are not present. biodiesel production from algae oil through the transesterification process using methanol and koh or naoh as catalyst was presented by tapore et al. [27]. three moles from methanol reacted with one mole of triglyceride which creates a mixture of biodiesel and glycerin. it has been discovered that transesterification is a very successful method for reducing the viscosity of vegetable oils and making them suitable for use in such diesel engines without any modification. the finding showed biodiesel from algae oil decreases the greenhouse impact on the atmosphere, by reducing co2 gas pollution, and improves the percentage of o2 in the exhaust gas compared to the ordinary diesel. chen et al. [28] developed a novel method for the production of biodiesel from wet microalgae. this method consisted of disrupting the microwave, removing partial water, extracting oil, and transesterification. the wet microalgae biomass with a moisture content of around 80 % was employed as the raw material for the production of biodiesel. methanol added to algae oil in different ratios such as 10:1, 8:1, 6:1, 4:1, and 2:1. in addition to 25, 35, 45 ,55 and 65°c of reaction temperature and reaction time of 5, 10 ,15 ,20 ,25 and 30 min. the results showed that the moisture content of wet microalgae decreased to approximately 50% after disrupting the microwave, and removing partial water. the recovery of oil from pretreated microalgae reached 90 % and transesterification conversion was greater than 90%. hossain et al. [29] presented a study to know the correct transesterification, the amount of biodiesel production and the physical properties of biodiesel. the authors compared the volume of biodiesel production using the popular species spirogyra and oedogonium. the findings pointed, in oedogonium, the production of algae oil and biodiesel was greater than in spirogyra species as shown in figure (4). the main outcomes of all studies mentioned are listed briefly in table 2. figure (3) flow diagram for the production of biodiesel from algae figure (4) biodiesel production in spirogyra and oedogonium sp. 162 mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 table 1 summary of algae oil extraction studies reference micro(algae) extraction process conclusions baig et al. [5] spirogyra sp. solvent extraction process using nhexane as solvent maximum amount of oil obtained as the solvent to algae ratio increased, longer contact time, smaller size of algal biomass topare et al. [4] not declared hexane solvent extraction, expeller method the solvent extraction process can be extended to any products with a low oil content shimi et al. [6] spirulina-platensis solvent extraction process using methanol as solvent (soxhlet extraction system) the fatty acid in spirulina is palmitic acid (48.35%) makes it a promising feedstock for production the biodiesel kanda and li. [7] microalgae (green-blue) dimethyl ether (dme) this approach has the advantage of reusing the water drained as a microalgae broth. abdullah et al.[8] chlorella vulgaris soxhlet extraction method too high temperatures in oil extraction can cause portion decomposition of the microalgae cells and thus reduce oil yields yoo et al. [9] chlamydomonas reinhardtii osmotic shock treatment osmotic shock increase lipid recovery nearly 2 times shah et al. [10] scenedesmus dimorphus sp. ultrasonic wave, soxhlet and expeller method the best way of reduce work was the soxhlet system shin et al. [11] not declared photo bioreactors (pbrs) reduced co2 emissions, appealing for recycling exhaust gases from power stations wiyarone et al. [12] nannochloropsis sp. ultrasonic and soxhlet extraction ethanol concentration has affected the quality of the algae oil halim et al. [13] marine chlorococcum supercritical carbon dioxide (scco2) decreasing temperature and increasing pressure resulted in increased lipid yields table 2 summary of algae biodiesel research works reference micro(algae) production method conclusions karmakar et al. [14] unused algae acid esterification + transesterification co and co2 reduction, higher nox lardon et al. [15] chlorella vulgaris esterification lca serves as a critical method for evaluating new energy generation technologies sánchez et al. [16] marine algae in situ transesterification n-hexane had no significant effect on the transesterification process miao, and wu [17] heterotrophic microalgae(chlorell a protothecoides) acidic transesterification producing high-quality microalga oil biodiesel using a new technique, which incorporated transesterification and bioengineering scott et al. [18] species of chlorella, haematococcus, and dunaliella transesterification and optimization method considered several factors that need to be optimized, including inputs of energy and materials (e.g. nutrients and energy for mixing during growth of algal biomass) hariram, and kumar [19] microalgae (spirulina sp.) transesterification co, hc, smoke and particulates emissions decreased while a slight increase in the nox emissions tüccar, and aydın [20] not declared transesterification(using naoh as the catalyst) brake power and torque values decreased, improved carbon and nox emission levels kammakar et al. [21] not declared transesterification(using koh as the catalyst) co2 can be used for microalgae growth and can reduce any kind of emission level akubude et al. [22] not declared nano catalyzed transesterification less costly, simpler and leaner process. yield more efficient mondal et al. [23] not declared transesterification reduce the proportion of co2 in the atmosphere, reduce global warming ahmed et al. [24] spirogyra sp. transesterification almost 95% of biodiesel was obtained using catalyst (sodium hydroxide) amount of 0.5wt%, contact time of 25 min at 60 °c and 1:8 molar ratio of oil/methanol fulke et al. [25] wastewater microalgae not declared mixed algae specimens showed the highest levels of co2 fixation aljabarin and al jarrah [26] not declared distillation process( using koh as the catalyst) decreases carbon dioxide emissions, so2 emissions are not present tapore et al. [27] not declared transesterification(using koh or naoh as the catalyst) reducing co2 emission, increase o2 in exhaust gas chen et al. [28] chlorella vulgaris transesterification(using koh as the catalyst( the recovery of oil from microalgae reached 90 % and transesterification conversion was greater than 90% hossain et al. [29] spirogyra and oedogonium species transesterification(using naoh as the catalyst) the production of algae oil and biodiesel from oedogonium sp. was greater than in spirogyra species mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 163 4. effect of microalgae biodiesel on the performance, combustion and exhaust emissions of diesel engine a great number of experiments were conducted by researchers from different parts of the world with biodiesel as a replacement for compression ignition diesel engine fuel. rajak et al. [30] investigated the characteristic of diesel engine numerically using the simulation diesel-rk software. the engine is powered by pure algae biodiesel and diesel at different compression ratios from 16.5 to 18.5. test engine experiments with an ideal compression ratio of 17.5 were conducted under maximum load conditions, and the results were compared with the numerical results. the products showed a 2.73% reduction in brake thermal efficiency, 6.66% reduction in torque, 1.6 reduction in exhaust gas temperature, 6.1% reduction in carbon dioxide, and 0.5% reduction in nitrogen oxide at full load condition under constant speed. however, sfc was increased by 6.4% at cr 17.5 as compared to pure diesel. naresh et al. [31] studied the emissions and performance characteristics of a diesel engine (4-stroke, direct injection) using algae methyl ester oil with varying exhaust gas recirculation (egr) control value of 5 to 20%. biodiesel and its mixtures displayed a significantly lower thermal brake efficiency relative to diesel fuel under various conditions of load. the energy consumption of fuels decreased as the amount of mixed fuels increases due to the reduced calorific values. nox and hc are decreased as the amount of egr increases. with higher rates of exhaust gas recirculation, the emissions and performance parameters are decreased. therefore, 15 % of egr is optimal for fuels to improve their performance and emission characteristics. rajak et al. [32] investigated the effect of spirulina microalgae biodiesel blending ratio on a naturally aspirated diesel engine at various loads. combustion, emissions, and performance analyses reported a reduction in cylinder pressure, exhaust emissions, exhaust temperature, and brake thermal efficiency relative to diesel fuel. regarding the emissions parameters, the spirulina microalgae biodiesel blends resulted in lower nox emissions of 4.9%, pm emissions of 20.7%, and lower smoke of 5.4%, but co2 emissions for all loads is increased. satputaly et al. [33] turned the microalgae oil gained from chlorella to biodiesel using the transesterification process. the produced biodiesel production was tested in kirloskar diesel engine with capacity 5.2 kw to analyze the combustion, performance and emission. the tests revealed a 3.09% decrease in thermal brake efficiency. the findings showed a decrease in co, unburned hydrocarbons, nitrogen oxide and smoke opacity emissions when fueled with methyl ester microalgae oil relative to diesel. algae oil derived from microalgae using soxhlet having viscosity equal to 8 times that of diesel, was blended in three different amounts with sunflower as follow: 5ml of algae oil + 95ml of sunflower oil (5:95), 10ml of algae oil + 90ml of sunflower oil (10:90) and 15ml of algae oil +85ml of sunflower oil (15:85) respectively, in order to reduce the viscosity. furthermore, the above mentioned mixture was transformed into biodiesel through two-step transesterification method with methanol. also, the three biodiesel forms produced were mixed in 10:90 ml with pure diesel (b10a%, b10b%, b10c%) the study involved examination of chemical and physical properties. the biodiesel properties produced conform to astm measurements. the results showed that brake thermal efficiency is higher by 2.77% for the b10c% biodiesel than that of the conventional diesel. likewise, the volumetric efficiency is increased by 1.52% for the b10c% biodiesel when compared with diesel (sankar et al. [34]). el-baz et al. [35] described the biodiesel preparation from microalgae oil. blends of 10% and 20% of biodiesel were prepared. the blends under study had physicochemical properties similar to diesel oil. biodiesel blend b20 indicated declined in specific fuel consumption, exhaust gas temperature, and increased thermal efficiency relative to diesel fuel and b10. the emissions of b20 has been reduced as opposed to b10 and diesel. it could be inferred that microalgae could be used to supply high quality biodiesel which can feed traditional diesel engines efficiently. rajak, and verma [36] investigated the characteristics of emulsion fuel with microalgae biodiesel (b20) and their consequences on exhaust emissions, combustion, and performance of a direct injection, diesel engine. the engine operated at three different engine speeds. the diesel engine powered by b0, b20, and b100 diesel at full load condition. the results showed, 0.55%, 6.2%, 1.63%, 2.6%, and 1.2% reduction in indicated thermal efficiency, oxides of nitrogen, cylinder pressure, smoke emission, and brake thermal efficiency respectively. b20 showed an increase by 4.5%, 5.08%, 2.45%, 2.7%, and 5.08% for peak heat release rate, specific fuel consumption, carbon dioxide emission, and ignition delay period respectively at 1500 rpm with a full load. the numerical results are checked against the results of experiments carried out under the same operating conditions. murthy et al. [37] focused on biodiesel production from freshwater chlorella vulgaris algae. the authors used the various blends of algae biodiesel and diesel with variable loads to analyzed the emission, combustion, and performance characteristics of diesel engines. it was noted that b20 has higher brake specific fuel consumption due to the difference in the heating value compared to pure diesel. reduction in nox, co and hydrocarbon emissions are observed. mahamudul et al. [38] explained that the usage of biodiesel and its blends marginally decreased engine power and raised fuel consumption but at the same time greatly lowered toxic emissions like hydrocarbons, particulate matter, carbon dioxides. the nox emission is increased. co2 emissions could be ignored as it is consumed by the crops themselves. it was fulfilled that biodiesel has the potential to be used in diesel engines as a substitute fuel for solving the energy and environmental crisis. makarevičienė et al. [39] conducted an experimental study on the employment of biodiesel containing (30% algae oil methyl esters (ame), and 70% fossil fuel) in valmet 320 dmg diesel engine onboard ship. it was found that use b30 reduced smoke exhaust emissions to 10–75%, and 5–25% reduction of hydrocarbons emissions (hc) with respect to diesel emissions. the engine thermal efficiency was 2.5–3 % higher while operated on b30 compared to diesel fuel operation. mathimani et al. [40] investigated the suitability of biodiesel derived from microalga chlorella vulgaris. biodiesel-diesel blends were tested in a single cylinder diesel engine subjected to variable load operations (0%, 50%, 75%, 100%) to analyze the performance and emission characteristics. engine powered with b50 reduced the hydrocarbon and co emissions by 102 ppm and 0.1% respectively compared to baseline diesel. the results showed 6.1% reduction in co2, and 376 ppm reduction in nitrogen oxides nox . reddy et al. [41] explained the possibility of using biodiesel derived from schizochytrium microalgae oil as an alternative fuel for fossil diesel engines. investigation was carried on diesel engine fuelled with microalgae biodiesel and its blends to evaluate the combustion, performance, and emission characteristics. the properties of biodiesel production were meeting the astm standards. the characteristics of the biofuel powered diesel engine compared with fossil fuel diesel engines were considered satisfactory. 164 mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 haik et al. [42] conducted an experimental study using the raw algae oil and its methyl esters in a diesel engine. in this study, the effect of heat release, engine speed, injection timing, compression ratio, engine load, combustion noise, and maximum pressure were studied. the properties of the algae oil methyl ester were shown to be similar to diesel fuel and their use has been effective in the smooth running of the diesel engine. however, its use marginally decreased the output torque engine and increased the noise from the combustion. the engine output can be increased and the noise from combustion can be reduced by regulating parameters of the engine design like compression ratio and injection timing. patel et al. [43] examined the suitability of biodiesel derived from indian microalgae. three different algal biodiesel blends namely 10%, 15 %, and 20% with fossil fuel, were tested on a diesel engine. noticeable reduction in unburned hydrocarbon, brake specific fuel consumption, and carbon monoxide is reported. moreover, the emissions nox increased significantly. it can be inferred that diesel fuel can be effectively blended with biodiesel algae to minimize fossil dependence by promising performance characteristics without any engine modification. the main concerns for the automobile industry are engine performance, emissions, and roughness. an experimental test was undertaken on a ricardo e6 indirect injection engine with a single cylinder for three different biofuels compared to pure diesel." one of the three fuels used is algae methyl ester ame ". there were two primary sets of experiments; first experiment, the engine torque (load) ranged from 0.5 to 15 nm, while the other parameters are injection timing, engine speed, and compression ratio. in second experiment, the injection timing ranged from (20° to 45°) btdc. the findings suggested that to accommodate the variety of biofuel characteristics, the fuel engine load and injection timing have to be adjusted. (ospina et al. [44]). the results of all discussed studies are described shortly listed in table 3. table 3 engine performance reference algae biodiesel tested engine conclusions rajak et al. [30] spirulina sp. b100 single cylinder , four stroke, 17.5 compression ratio, 3.7 kw reduction in brake thermal efficiency, , torque, exhaust gas temperature, carbon dioxide nitrogen oxide when using b100, increased in sfc naresh et al. [31] not declared b20, b40, b60 direct injection, , four stroke, water cooled , 17.5 compression ratio, 5.9 kw, kirloskar engine lower thermal brake efficiency, nox and hc decreases as the amount of egr increase for biodiesel rajak et al. [32] spirulina sp. b0,b20, b40, b100 kirloskar diesel decrease in the ignition delay period as compared to original diesel. decrease in egt and bte satputaly et al. [33] chlorella b0, b100, raw algae oil kirloskar diesel engine, single cylinder, water cooled, capacity 5.2 kw reduction of co, unburned hydrocarbons, nox and smoke opacity emissions sankar et al. [34] spirulina sp. b10a, b10b, b10c 5hp single cylinder,4 stoke, water cooled, diesel engine higher brake thermal efficiency for b10c compared to diesel, b10c gives the best result el-baz et al. [35] scenedesmus obliquus b10, b20 kirloskar, single cylinder four stroke, water cooled, diesel engine lower bsfc, egt, higher brake thermal efficiency, lower emissions for b20 rajak, and verma [36] spirulina sp. b0, b20, b100 single cylinder, four stroke, direct injection, diesel engine .lower thermal efficiency, nox, cylinder pressure, smoke emission and particulate matter for b20 murthy, and kumar [37] chlorella vulgaris b10, b20 kirloskar tv-i di, four stroke, single cylinder, capacity 3.6kw, water cooled reduction in nox ,co and hydrocarbon emissions for b20 mahamudul et al. [38] not declared diesel engine increased in nox and bsfc, reduction in brake power makarevičienė et al. [39] chlorella sp. b30 valmet 320 .dmg diesel engine onboard ship reduced smoke exhaust emissions to 10–75%, 5–25% reduction of hydrocarbons emissions mathimani et al. [40] chlorella vulgaris b30, b40, b50, b60, b100 kirloskar, four stroke, single cylinder, water cooled, decreases the hydrocarbon, co, nox and co2 emissions reddy et al. [41] schizochytriu m sp. b20, b40 and b60 kirloskar,av1, single cylinder, vertical, four stroke, capacity 3.7kw weak atomization and rising exhaust gas temperatures gave lower thermal efficiency, lower hc, higher bsfc, nox and co, decreased in ignition delay y. haik et al.[42] ankistrodesmu s braunii and nannochlorops is. a. braunii b0, b50, raw algae oil ricardo e6 single cylinder, indirect injection diesel engine decreased the output torque engine and increased the noise from the combustion, decrease in the compression ratio of the engine resulted in diminishing the noise of combustion patel et al. [43] chlorella vulgaris b10, b15, b20 kirloskar , single cylinder, vertical, four stroke, water cooled reduction in unburned hydrocarbon (ubhc), brake specific fuel consumption (bsfc), carbon monoxide (co). ospina et al. [44] not declared b0, b100 ricardo e6 , single cylinder, four stroke, direct injection, diesel engine reduction in peak pressure, higher nox emissions mariam emad murad and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 13 (2020) 158–166 165 5. conclusion this paper presents a comprehensive literature review of the most published papers in the field of extraction algae oil, algae biodiesel production, and its effect on performance, emission and combustion. a lot of points could be drawn:  although various sources of renewable energy are presently being used, the prospects of generating microalgae biofuels look promising due to their unique characteristics.  the key of success in the microalgae biofuel production is the costefficient and successful extraction of lipids.  microalgae cells can produce and extract lipids. this lipid can be utilized in transformation to biofuel particularly biodiesel. this transformation reduces the emissions of petroleum, coal, nuclear power, hydro, and natural gas, which is a significant cause of greenhouse gas (ghg) emissions.  due to the higher oxygen content of the biodiesel compared with diesel, early start of combustion is observed.  sight reduction in the brake thermal efficiency is reported while the bsfc is increased.  during the combustion process, biofuels may result in a decrease of toxic emissions such as co2, co, unburnt hydrocarbon and soot.  nox is one of the important conditions for the diesel engine studies to be addressed. nox forming in an engine is determined by the temperature of combustion and the rate of heat release. consequently, the higher combustion temperature of the engines resulted in increased nox emissions.  most literature papers in this context are based on experimental studies. a clear lack in the theoretical studies is detected, hence more theoretical and simulation works are required to bridge the gap. references [1] m. f. al-dawody, s.k. bhatti, computational combustion and emission analysis of biodiesel in a variable compression ratio engine, al-qadisiyah journal for engineering sciences, 12 (2019). 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[44] g. ospina, m.y. selim, s.a. al omari, m.i.h. ali, a.m. hussien, engine roughness and exhaust emissions of a diesel engine fueled with three biofuels, renewable energy, 134 (2019) 1465-1472. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٥ studying heat transfer and fluid flow distribution on heated fin inside rectangular duct with using triangular protrusion dr. ahmed hashm yousif abas naji dr. kareem dakeel jasem mechanical department mechanical department mechanical department al-diwania technical al-diwania technical al-diwania technical institute institute institute abstract the structure of flow and heat transfer characteristics over a heated fin (at constant heat flux) in rectangular duct with using triangle protrusion has been studied numerically. an incompressible flow and finite volumes method (fvm) in general coordinates with collocated grid arrangement are used to solve two dimensions continuity, navier – stokes and energy equations. the prandtl number and reynolds number are takes as 0.71 and 2000 respectively. at present study, different lengths of base of triangle protrusion (d/h = 0, 0.26, 0.53, 0.8, 1.07, 1.33) at (l/h= 0.13) was used. the results were compared with the case of flow inside duct without using protrusion. the results indicate that heat transfer and pressure drop is affected by the length of protrusion base especially near the triangle protrusion. the results illustrate that the heat transfer will be increasing with decreases the length of protrusion base. this study identifies an enhancement in the average heat transfer with increasing in pressure drop. ����د ���ء ��� � ��� ز���� ����� دا� ��ى �درا�� ا��'�ل ا�%�ارة و��!�ن ا���ا +�+* ا�() آ�!. دا� ���.. د � ��5س ���* �3 ا2�1 ه�/. !�� . د 7 ��( � 7 8�. ا���( � 7 8�. ا���( � 8�. ا� ا�1!�ا� �– ا��:19 ا��'�* ا�1!�ا� � – ا��:19 ا��'�* !�ا� � ا�1–ا��:19 ا��'�* ا�<=>� �د���� ��� ���� ����اص ا������ل ا���� ارة وا� ����ن�1$��+0 (دا���* �� ى -��,�(+* ا���(��) �'��& ز�#$��� �����#� أ! ��� درا���� ���ن c ا��8=�ab (fvm)@? أ��<�م = ���� ا�� ��م ا�����دة . ���ء -9'89 ا�67* �1!�د) 4 اري 1�2 � ، e�+@ @ ام�و@�? ا���< � ، ����ك – ��* -���دcت ����+ collocated grid ا�f �6g7+ ا���#�و�1��g�ا ��+k�#2 ��l�)��6'�� وا�ا���* . ا 1 ?�lر mأ�� ?�@ ��l0.71و . 2000ورl? ر�#���ز �= +2n@ ��#���ء @� درا�ة ا���l ل(d/h = 0, 0.26, 0.53, 0.8, 1.07, 1.33) ارة ���وا�����ل ا oab���1 ط��gq�ا &�'� �'& ا�t$+�� دا�* ا�� ى s+4 إن )(h ى أو��w . @? -��ر�� ا�#��vk -) �4�� ا� ��ن 1�ون ا��<�ام ����ء . ��9* ار@$�ع ا�� �'& ا��gqط �1�oab وا�� +gآ #��ء ا2�ا اmq� أن vk��#�ا�y�tو� ��+$t�ا &'�1+# ه�m\ ا��را��� أن . l ب ا�#��ء" ��ل ا�� ارة oab�ط ا�gq1 #��ء -) ز��دة�ارة ���,^ �1!�د ا ��ل ا����ل ا�� . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٦ nomenclature symbol description unit a convection-diffusion discritization coefficient a1, a2 transformation coefficients b channel length m c p static pressure coefficient d length of protrusion base m d diffusion term coefficient f mass flux h channel height m hij local heat transfer coefficient w/(m 2 .k) j jacobean of transformation m k thermal conductivity w/(m.k) l triangle protrusion height nu nusselt number p source term in grid generation system of equation pressure n/m 2 p0 total pressure n/m 2 pij local static pressure n/m 2 p r prandtl number q heat flux per unit area w/m 2 q source term in grid generation system of equation re reynolds number s source term for the dependent variable ф t temperature k u velocity in x-direction m/s u, v contravariant velocities v velocity in ydirection m/s x, y cartesian coordinates greek symbols symbol description unit ξ, η general coordinates ф general variable α thermal diffusivity µ kinetic viscosity kg/m3 ρ density kg/m3 γ coefficient of diffusivity abbreviation symbol description unit 2-d two dimensions fvm finite volume method n-s naveir-stoke equation pde partial differential equation al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٧ subscripts symbol description unit b bulk e,w,n,s face of control volume e,w,n,s neighbor nodes of node (p) f fluid p center of control volume ij index control in ( x,y) or (ξ, η) direction in inlet condition ф total source of ф transport property w wall introduction compact heat exchangers are widely employed in engineering application, especially in automotive industry, air conditioning and refrigeration apparatus (ahmed 2003). the improvement in design of these heat exchangers has attracted many researchers. the heat transfer coefficients on the flat surface are significantly law due to increase the boundary layer thickness and in order to increase the heat transfer between the gas and fin in plat fin heat exchanger, protrusions can be used on the flat surface (isak,1998). many researchers used different types of vortex generators to generate a longitudinal vortex to mixing the fluid near the wall with main fluid that lead to remove heat near the wall to the main flow. in plate – fin or tube heat exchangers the flow between the plates can be considered as a duct flow. to reduction the thermal resistance, the heat transfer coefficient need to be augmented (tiggelbeek,1991). in plate – fin heat exchanger, the heat transfer coefficient is significantly law and in order to increase heat transfer between the fluid and plates, protrusions or vortex generators can be use and fluid flow and heat transfer on flat plates with using vortex generators was experimentally and numerically investigated. the researchers (ahmed 2003), (biswas, 1992) and (fiebig, 1989) are investigated flow and heat transfer on flat – plate with using wing and winglet type vortex that the heat transfer enhanced by using vortex generators with increasing in pressure drop across the plates. the studies of (tiggelbeek, 1991), (isak,1998) and (russell, 1982) investigated the flow and heat transfer from plates with using obstacles and vortex generators experimentally. the studies show that heat transfer enhanced with using obstacles and vortex generator. one relevant application using such flow configuration is the heat transfer between the flow and plates in the case of plate fin heat exchangers,as shown in figure (1) (isak,1998). in the present paper, a numerical investigation is described to study forced convection heat transfer with using single triangle protrusion in a rectangular channel as a part of plate – fin heat exchanger with different ratio d/h = (0 , 0.26 ,0.53 ,0.8 ,1.07 ,1.33 ,) at (l/h =0.13) as showing in figure (2) for re=2000 and pr=0.71. the local heat transfer in front region of plate is relatively high and decreases toward the rear due to growth of boundary layer, therefore the strategy of this study is to place a triangle protrusion in the middle of channel to mixing the fluid near the wall with the main fluid and to increase the velocity of flow near the protrusion to sweep the hot area or to make a vortex in the flow. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٨ mathematical model the mathematical analysis is presented for partial differential equation (pde) which describe fully developing flow and heat transfer at re=2000 in parallel plate channel. incompressible flow and steady state is assembly in entrance region with neglecting body force, heat conduction and free convection. grid generation figure (3) show the schematic of two dimensions body fitting grid used for present computation, this grid obtained by solving non homogeneous 2-d laplace equations (thompson, 1977). ξxx+ ξyy =p(ξ, η) (1) ηxx+ ηyy=q(ξ, η) where p and q are used to cluster the grid near the wall to sense the velocity gradient because there is a friction between the wall and the fluid. equations (1) are transformed to (ξ, η) coordinates by interchanging the roles of dependent variables. this yields the following system equations. g11xξξ –g21xξη +g22xηη =-j 2 (pxξ+qxη) (2) g11yξξ –g21yξη +g22yηη =-j 2 (pyξ+qyη) where g11= 22 ηη yx + g21=2(xξxη+yξyη) g22= 22 ξξ yx + j=xξyη-xηyξ because the geometry of the domain was complex the (2-d) n-s, continuity and energy equations must be transported to general coordinates (ξ, η). physical and computational plane with collocated grid arrangement can be seen in figure (4). governing equations the 2-d governing equations of mass, momentum and energy equations for steady incompressible flow can be written as follows: continuity equation 0= ∂ ∂ + ∂ ∂ y v x u (3) momentum equation al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٩ 2 2 2 2 1 1 x v u y p y v v x v u y u v x p y u v x u u ∂ ∂ + ∂ ∂ −= ∂ ∂ + ∂ ∂ ∂ ∂ + ∂ ∂ −= ∂ ∂ + ∂ ∂ ρ ρ (4) energy equation 2 2 y t y t v x t u ∂ ∂ = ∂ ∂ + ∂ ∂ α (5) the above equations can be written in a general transport equation as : φφφ φφφρφρ s yyxxy v x u +      ∂ ∂ γ ∂ ∂ +      ∂ ∂ γ ∂ ∂ = ∂ ∂ + ∂ ∂ )()( )()( (6) this equation serves as a starting point for computational procedure in (fvm), by setting (ф=1, γф=0 and sф=0) the continuity equation can be obtain, by setting (ф=u, v and γф=µ ), n-s equation can be obtain and by setting (ф=t and γф=µ /pr ) the energy equation can be obtain. the two terms in the left of the general transport equation (6) are convective terms, the first two terms in the right side of general transport equation (6) are diffusive terms and the last term is the source term. for the general curvilinear coordinates system (ξ, η), the general transport equation (6) can be transformed to the following form: new s j a v j a u = ∂ φ∂γ −φ ∂ ∂ + ∂ φ∂γ −φ ∂ ∂ φφ ) 2 () 1 ( η ρ ηξ ρ ξ (7) where (u, v) are the contravariant velocity components as shown in figure (5). and snew =js+sn where sn is the source term due to non orthogonal characteristic of grid system which disappear under orthogonal grid system. the transformation coefficients (a 1 , a 2 )are defined as: 22 22 2 1 yx yx a a ηη ξξ += += (8) and the transformation metrics are calculated as follows j x j y j x j y y x y x ξ ξ η ξ η η ξ ξ = − = − = = (9) for collocated grid arrangement, all properties must be at the center of control volume (p) as shown in figure (4). and the integration of equation (7) over control volume gives al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٠ new n s e w dvs j a v j a u =∆ φγ −φ+∆ φγ −φ φφ ]) 2 ()[(]) 1 ()[( ξρηρ ηξ (10) where dv=jξ jη to interpolate convection and diffusion terms, the power law difference scheme (patenker, 1980)can be used, and the following algebraic equation can be obtained: apфp = aeфe+ awфw+ anфn+ asфs+ dv snew (11) where ae= de*a (│pje│)+[[-fe, 0]] aw=dw*a (│pjw│)+[[fw, 0]] an= dn*a (│pjn│)+[[-fn, 0]] as= ds*a (│pjs│)+[[fs, 0]] ap= ae+ aw+ an+ as when (f) is the mass flux and (d) is the diffusion term coefficient in order to avoid the checkerboard pressure field in collocated grid system, a momentum interpolation technique on cell face was successfully proposed by rhie and chow interpolation method that developed by ( ferzigen, 1999). boundary conditions the (fvm) required that the boundary flux, either be known or expressed in term of known quantities on interior nodal value. the boundary of the present work include solid wall, inlet and outlet planes. 1 inlet boundary usually at inlet boundary, all quantities have to be prescribed as follows: (u)inlet=uin (v)inlet=vin (p)inlet=pin (12) (t)inlet=tin 2 outlet boundary always all values of dependent variables are unknown at exit boundary. it is often adequate to set outlet boundary values equal to intermediate up stream neighbor (e.g фe= фp). this is equivalent to saying the first derivative of property ф in the direction normal to the boundary is equal to zero. 0 0 0 0 = ∂ ∂ = ∂ ∂ = ∂ ∂ = ∂ ∂ x t x p x v x u (13) 3 wall boundary the velocity on the wall equal to zero u=v=0 the first derivative of pressure in the direction normal to the wall equal to zero 0= ∂ ∂ y p (14) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨١ for constant heat flux on bottom plane ijw t k y qt += * (15) and for adiabatic for top plate 0= ∂ ∂ y t (16) heat transfer and pressure drop calculations the aim of present numerical study is to know logically the effect of triangle protrusion on local heat transfer and pressure drop by calculation nusselt number (nu) and pressure coefficient (c p ) as follows. 1 heat transfer calculation to calculate nusselt number (nu) from heated wall at constant heat flux, first the temperature distribution can be calculated from the following equation. n t kq wall ∂ ∂ −= (17) where n is the normal distance then calculate local nusselt number (nuij) as follows: qwall=qconv (18) qwall=h(ij)*(t(ij)-tb) (19) nu(ij)=h(ij)*h/kf (20) 2 local static pressure coefficient the local static pressure coefficient along the wall surface can be calculated as follows: cp(ij)= 2 )( 5.0 )( in oij u pp ρ − (21) results and discussion a number of computations have been performed at different (d/h) for protrusion. figure (6) shows the stream lines for the flow in channel without using protrusion (free case). there is no change in direction of stream and no vortex appears. figure (7) shows the stream lines for the flow in channel with using triangular protrusion with different (d/h). when (d/h) be a large value, the effect of protrusion is nearly equal to free case but when it be small, the procedure of velocity vectors will be changing when the flow reaches the protrusion and the direction of velocity will be changing toward the main flow, and due to the high momentum of the main flow in the middle of channel, the velocity will be change its direction behind the protrusion as in figures (a, b). at small (d/h) the vortex will be appearing behind the protrusion because pressure different across the protrusions as in figures (c, d, e and f). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٢ figure (8) shows the temperature contours for flow inside channel without using protrusion, the temperature gradient due to the thermal resistance (thermal boundary layer) clearly appeared, the thermal resistance at entrance of channel is equal to zero and it increases toward the rear due to the growth thermal boundary layer. figure (9) shows the temperature contours for flow inside channel with using protrusion with different (d/h), the temperature gradient is different from the free case because of destroy the thermal boundary layer, also the figures shows that the heat transfer will be increasing in front of protrusion due to sweeping the heat toward the main flow but it be decreasing behind the protrusion. figure (10) shows the pressure coefficient at different protrusion base along the channel. the figure shows that when the protrusion base be small [(d/h) be small], the pressure drops will be increasing near the position of protrusion since the different across the faces of protrusion and it will be decrease when increasing (d/h). maximum local pressure drop occur was at d/h=0. figure (11) shows the nusselt number distribution along the plate surface for free case and with using triangle protrusion with different (d/h), the figure shows that the local heat transfer before the protrusion position for all cases are equal and its will be changing when the flow reaches the protrusion, heat transfer will be increasing at the front face of protrusion because of the flow will be sweeping the heat at this region and nusselt number reaches maximum value at the tip of protrusion. at the rear face of protrusion, heat transfer will be increasing slightly because of the vortex of flow will be appearing in the rear of protrusion specially at small (d/h) and the effect of the triangle protrusion will be continuing to the rear of plate. maximum local heat transfer occurs at d/h=0.26. figure (12) shows the comparison of local nusselt number for free case between the present study and reference (ahmed, 2003) at the same conditions, the figure shows that the same procedure in two carves. conclusions local heat transfer and pressure drop of plate fins with using protrusions have been measured and compared with free case. the most important results can be summarized as follows: • protrusion accelerate the flow to sweep the heat from high heated region in plates, also it's mixing the hot fluid near the wall with the cold fluid at the main flow. • average heat transfer enhanced (6% -21%) when using protrusion with different ratio of (d/h). • maximum average heat transfer enhanced when using protrusion with (d/h= 0.26). • pressure drop more than free case when using protrusion and average pressure drop increased (2% -16%) with using protrusions with different ratio of (d/h).. • pressure drop increases when decrease d/h. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٣ references 1ahmed, s. and lars, d. "numerical study of heat and flow in platefin heat exchanger with vortex generators " turbulence heat and mass transfer4, pp 1155-1162, 2003. 2ahmed, h. jallal, j and hassan, k. "enhancement heat transfer from heated cylinder inside duct by using vortex generators" phd thesis, mechanical engineering department university of technology, iraq, 2006. 3biswas, g. and chattapdhyay, h "heat transfer in channel with built in wing typevortex generators " int. j. heat mass transfer vol.15, no.4, pp 803-814, 1992. 4fiebig, m. brockmeier, u. mitra, n. and guntermann, t "structure of velocity and temperature fields in laminar channel flow with longitudinal vortex generators " numerical heat transfer, part a, vol.15, pp 281-302, 1989. 5ferzigen, j. and peric, m. "computational method for fluid dynamic" 2-th edition springer, berlin, 1999. 6isak, k. teoman, a. hayati, o. and betiil, a. "heat transfer and flow structure in rectangular channel with winglet type vortex generators " tr. j. of engineering and environmental science, vol.22, pp 185-195, 1998. 7patenker, s. v. "numerical heat transfer and fluid flow. hemispere publishing mc graw hill book co. 1980. 8russell, c. jones, t. and lee, g. "heat transfer enhancement using vortex generators " seventh int. heat transfer conf. munich, federal republic of germany, pp 283-288, 1982. 9tiggelbeek, s. mitra, n. and fiebig, m. "comparison of wing type vortex generators for heat transfer enhancement in channel flows " asme, vol. 116, pp 880-885, 1991. 10 thompson, j. f. thomas, f. c. and mastin "tomaca-a code for numerical generation of boundary fitted curvilinear coordinate system on field containing any number or arbitrary 2 -d bodies " j of computational physics, vol/24, pp 274-303, 1977. 11 yunliang, w. and satoru, k. "production of duct flows with a pressurebased procedure " numerical heat transfer, part a, vol/33, pp 723-748, 1998. (a) (b) (c) figure (1) surface geometries for platfin heat exchanger (a) plain rectangular fins, (b) plain triangular fins, (c) perforated fins al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٤ b flow h x l d figure (2) proposed flow domain figure (3) grid generated y adiabatic wall constant heat flux wall p p e e w w n n s s ( a ) (b) u v t figure (4) (a) physical plane (x,y) (b)computational plane (ξ,η) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٥ ξ x η v u y d/h=1.33 figure (5) the contravariant velocity components figure (6) stream lines for free case free d/h=0.53 d/h=1.07 d/h=0.8 (a) (b) (d) (c) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٦ d/h=0d/h=0.26 1 1 2 3 4 5 5 7 8 9 11 11 57.95 10 43.11 9 38.78 8 37.33 7 37.03 6 37.01 5 37.00 4 37.00 3 37.00 2 37.00 1 37.00 t(c) free case 10 8 6 5 4 3 2 1 1 10 65.34 9 52.89 8 43.21 7 39.18 6 37.31 5 37.10 4 37.02 3 37.00 2 37.00 1 37.00 t(c) d/h=1.33 figure (8) temperature contour for free case (f) (e) figure (7) stream line distribution (a) d/h=1.33, (b) d/h=1.07 (c) d/h=0.8, (d) d/h=0.53, (e) d/h=0.26, (f) d/h=0 9 6 6 4 3 2 1 1 6 9 69.65 8 65.64 7 59.44 6 46.59 5 40.00 4 37.28 3 37.03 2 37.02 1 37.00 t(c) d/h=1.07 10 8 7 6 5 3 2 2 8 1 10 71.06 9 58.33 8 48.53 7 40.74 6 37.70 5 37.16 4 37.03 3 37.01 2 37.00 1 37.00 t(c) d/h=0.8 8 8 6 3 3 2 1 1 7 1 10 73.49 9 63.88 8 53.93 7 49.51 6 47.11 5 44.87 4 40.64 3 37.31 2 37.02 1 37.00 t(c) d/h=0.53 (a) (d) (c) (b) (e) (f) 10 8 6 5 3 2 4 5 10 79.22 9 53.62 8 50.76 7 46.88 6 44.32 5 42.20 4 38.29 3 37.20 2 37.04 1 36.11 t(c) d/h=0.26 8 7 6 5 2 1 8 4 2 2 10 84.82 9 79.68 8 70.72 7 51.03 6 44.29 5 40.39 4 38.21 3 37.59 2 37.04 1 36.11 t(c) d/h=0 figure (9) temperature counters (a) d/h=1.33, (b) d/h=1.07 (c) d/h=0.8, (d) d/h=0.53, (e) d/h=0.26, (f) d/h=0 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٧ figure (10) pressure coefficient distribution figure (11) nusselt number distribution figure (12) comparison of nusselt number with reference [1] 0 1 2 3 4 5 6 7 8 9 10 x/h -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 c p d/h=0 d/h=0.26 d/h=0.53 d/h=0.8 d/h=1.07 d/h=1.33 free 0 2 4 6 8 10 x/h 5 10 15 20 25 30 35 40 n u d/h=0 d/h=0.26 d/h=0.53 d/h=0.8 d/h=1.07 d/h=1.33 free 0 2 4 6 8 10 x/h 5 10 15 20 25 30 35 40 45 50 n u present study refrence[1] introduction al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 experimental investigation of performance and exhaust emissions of a diesel engine with scrap tires rubber oil blended diesel fuel. nabel kadum abd-ali * * materials engineering dep., college of engineering, al-qadisiyha university. nabelkadum@yahoo.com received 4 january 2016 accepted 16 march 2016 abstract using of scrap tires will result in recycle the waste of rubber products and solve the problem of increasing the prices of mineral fuel. different blends of scrap tires rubber oil (stro) and diesel fuel have been investigated experimentally using diesel engine for performance and emission products. a blend of 10, 20, 30, 40% and standard diesel fuel have been tested in the diesel engine and the results showed a good improvement in reducing the pollutants. one of the important problems facing the mixed with fuel oil is to increase the viscosity and decreasing volatility that lead to carbon deposition and ring sticking of these types of oils. when blended with diesel, (stro) presented lower viscosity, improved volatility, better combustion and less carbon deposit. nox emission for the blend of 20% scrap tires rubber oil (stro 20) was reduced by 40%. an increase in emission of hydrocarbon by 20% was found at full load. the emissions of carbon monoxide (co) from scrap tires rubber oil and its blends were higher except in (stro 20) blend that reduced by 15%. the brake thermal efficiency was spotted higher with standard fuel than scrap tire rubber oil and its blends. the present work showed that the 20% blending ratio is the optimum blending ratio for scrap tires rubber oil depending on experimental test results. also, the current study introduce the waste of rubber products as a good alternative fuel blended with diesel fuel verify economical and environmental benefits. keywords: scrap tires, rubber oil, blending fuel, mineral diesel, emission, thermal efficiency. بزيت الممزوجالديزل بوقود التحقيق التجريبي ألداء وانبعاثات العادم من محرك الديزل التالفة.طارات الإمطاط م.د. نبيل كاظم عبد علي جامعة القادسية. -كلية الهندسة -المواد هندسةقسم . خالصة تشكيل وفحص كفاءة االداءوقد تم .أسعار الوقود المعدنيزيادة بسبب وقود بديليجاد أل التالفةالمطاطية اإلطارات إعادة تدوير تم اس األداء يلقوقود الديزل تجريبيا باستخدام محرك الديزل مع (stro) التالفةاإلطارات زيت مطاط خلطات مختلفة من ل وقود الديزل مع ( 01%، %01، 21%، 01% ) منبنسب تتراوح زيت مطاط االطارات التالفة وقد تم اختبار مزيج واالنبعاثات. mailto:nabelkadum@yahoo.com al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 عالية في لزوجة ذو طرحت المشاكل الشائعة عند استخدام زيت حيث .القياسي وأظهرت النتائج تحسنا جيدا في الحد من الملوثات التصاق حلقات الضغط والتي تحدث نتيجة اختالف لزوجة الزيوت و الكربون ترسب ضعف التذرية،مثل محركات اإلشعال تم .لكربونل ترسبخفض اللزوجة، تحسين التقلب، احتراق أفضل وأقل (stro) الديزل، قدموقود مع المزجعند المتنوعة. تم العثور على الزيادة في .٪01مزيج بنسبة (stro 20) التالفةاإلطارات مطاط زيتتخفيض انبعاث أكاسيد النيتروجين على اإلطارات مطاط مزيج وقودمن (co) ثات أول أكسيد الكربونكانت انبعا .٪ في حمولة كاملة21انبعاثات الهيدروكربون بنسبة لوحظ ارتفاع الكفاءة الحرارية مع الديزل وبشكل قليل .٪02مزيج حيث تم تخفيض بنسبة (stro 20) أعلى إال في حالة التالفة مطاط للوقود مع زيت أمثلمزج نسبةك٪ 21نسبة مزج تقترح هذه الدراسةكذلك .لوقود المزيج مع زيت االطارات التالفةلالعادي تقدم الدراسة الحالية زيت مطاط االطارات التالفة كوقود بديل مزيج مع وقود محركات الديزل لتحقيق منافع .التالفةاإلطارات اقتصادية وبيئية. introduction recycling the waste generally solves two important issues for the humanity and the human beings in the earth planet. one of the hugest types of waste disposed every year by millions of tones is the car tires. solving this issue is crucial mater economically and environmentally worldwide. in iraq, although there are many tires factories such as al-diwaniyah tires factory and babylon tires factory in additional to many other rubber industries which increasing of the disposed tires, but there are no approaches to put real policies to recycle the wasted rubber material and tires and convert these materials into useful eco-friendly materials. tires mainly composed of different rubber compounds like vulcanized rubber, rubberized fabric, reinforcing textile cords, steel or fabric belts and steel-wire reinforcing beads. different types of tires used nowadays natural and synthetic rubber such as natural rubber (cis-polyisoprene), styrenebutadiene rubber (sbr), cis-polybutadiene rubber (brcis). another important components in tire manufacturing such as reinforcement agents, accelerator agents, anti ozinant agents, anti-oxidant agents, softening agents and other additives used in the tires[1]. scrap rubber can be obtained from used tires by mechanical cutting into small chips. many methods were investigated to eliminate this rubber waste like combustion, pyrolysis and hydrogenation. the use of scrap rubber for fuel is one of the best alternative processes for reusing rubber as natural gas and fuel oil costs increases. pyrolysis, gasification, and liquefaction (pgl) represent a viable alternative methods for the disposal of scrap tires (waste tires). these technologies are currently used for the conversion of carbonaceous materials more extensively in europe and japan than in usa california, but may become more important as the supplies of natural fuels become depleted [2]. pyrolysis techniques were used extensively in the literature to treat or recycle the waste tires. in the absence of oxygen in high temperature, scrap/waste tires can be decomposed via pyrolysis leading to the production of solid carbon residues, condensable fractions and gases[3]. the two parameters effect on the thermal decomposition of tires were tire composition and temperature. the pyrolysis of williams and besler [4] showed that, the major components of rubber tires: styrene–butadiene rubber (sbr), natural rubber (nr), and polybutadiene rubber (br), the tire pyrolysis was done by a swept fixed bed reactor and nitrogen as carrier gas. also, many authors such as kaminsky et.al.[5] and kawakami et.al. [6] had been used different types of reactors like fluidized bed reactors and rotary kilns, the work of both authors was done at higher temperatures than williams and besler [4] and they found that the liquid products yield was decreased and a higher gas formation was obtained. in another studies, the authors obtained an active carbon from old tires using pyrolysis [7,8]. the co-processing of old tires with coal was the subject of many studies looking for a coal hydrogenation process enhancement [9–21]. the study of gonzalez et al. [22] showed that the products of automobile tire waste pyrolysis in nitrogen atmosphere were approximately 37–40% char, 55% oil, and 4–11% gas. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 the waste is an important source of renewable energy and considered as a potential to the world’s energy. being a source of green energy, these wastes make them a potential alternate for diesel fuel. there are many waste oils identified by the researchers, which could be used as engine fuels. the use of biodiesel provide reductions in particulate matter, carbon monoxide and unburned hydrocarbon emissions. the studies on the substitution of diesel fuel by 20% blend showed a decreases in the emission of particulate matter on average by 25% for engines and meeting the standard for the pollutant emissions[23]. the previous studies showed that, the brake thermal efficiency outcomes of biodiesel-diesel fuel blending include slight elevations [24-33], a slight reduction [34,35] and unfounded variations [3639]. the reasons for these results may be attributed to the reduction in friction power due to biodiesel lubricity [27,40], present of oxygen in biodiesel [27,31], increase in combustion efficiency [24,25,30], improving the combustion characteristics [41] and variations in fuel vaporization and ignition processes [29]. some authors identified a balance between the increased thermal efficiency and the fuel’s reduced heating value which lead to change in the specific fuel consumption (sfc) affected by the biodiesel blend. the results indicated that the minimum (sfc) is achieved with diesel fuel of 10% [24,29,32,40], 15% [34] or 20% blending with biodiesel fuel [25,27,31]. in 2012, g. kasiraman et. al [42], studied the performance, emission and combustion characteristics at various loads on the engine at a constant speed of 1500 rpm they found that the blends of 30% camphor oil shows good performance with diesel fuel operation with respect to brake thermal efficiency and heat release rate at full load. also results showed experimentally that, the brake thermal efficiency of camphor oil blend 30 is 29.1% compared to base diesel engine brake thermal efficiency of 30.14%. the camphor oil blend 30 emits 1040 ppm of nitric oxide, while diesel emits 1068 ppm. the neat cashew nut shell oil emits 983 ppm of nitric oxide [42]. to the best of our knowledge, no previous research has been conducted on the performance and emissions of scrap tires rubber oil (stro) produced from tires of al-diwaniya tire factory blended with diesel fuel. so, the present study will investigate the performance, emission and combustion characteristics of a diesel engine fueled with scrap rubber oil (stro) and its diesel blends compared to those of standard diesel and introduce this material as a good alternative material verifying economical and environmental benefits result from using scraped material. experimental tests electrical laboratory furnaces under vacuum condition including spiral condenser were used to extract oil locally in (450-500 0 c) from truck tire cross-play reinforced by nylon fabric that manufactured by al-diwaniyah tires factory. these tires composed of natural and synthetic rubber (nr, sbr, brcis), reinforcement agent (carbon black), mineral plasticizer (aromatic) oil, vulcanization agent (sulfur), zinc oxide, stearic acid, retarder agent, accelerator agent, antioxidant agent, antiozonant agent, activators agent …etc. according to italian pirelli co. recipes. the engine was operated on standard diesel fuel first and then on scrap rubber oil-diesel fuel blends with 10%, 20%, 30%, 40% scrap tires rubber oil and neat scrap rubber oil. four blending fuels were studied and employed in the experiments in addition to standard diesel fuel, and pure scrap rubber oil. the blends were 90% diesel fuel and 10% scrap tire rubber oil (stro 10), 80% diesel fuel and 20% scrap tire rubber oil (stro 20), 70% diesel fuel and 30% scrap tire rubber oil (stro 30), 60% diesel fuel and 40% scrap tire rubber oil (stro 40). it can be seen that scrap tire rubber oil blends easily with the standard fuel and get the economic homogeneous mix for long periods. also, such substance can be obtained from the local markets with good specifications. the properties of the diesel fuel was listed in table (1). al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 flash point which used in shipping and safety regulations to define flammable and combustible materials was measured by syd-3536 coc flash point apparatus (shanghai shenxian instrument co.) according to astm d93. the carbonaceous residue is reduced to an ash by heating in a muffle furnace at 775°c, according to astm d482. moisture was measured according to standard specification for diesel fuel oils astm d975 and astm 396 for calculating fixed carbon. gross calorific value determined by calorimeter vessel according to astm d2015. accurate determination of the density; relative density (specific gravity) was done according to astm d1298. also, the kinematic viscosity of liquid petroleum products was calculated by measuring the period of flow the fixed volume of liquid at a specific temperature by syd-265c petroleum products kinematic viscosity tester (shanghai shenxian instrument co.), according to astm d445. the heat of combustion as determined by astm d240 is designated as one of the chemical and physical requirements; the mass heat of combustion, the heat of combustion per unit mass of fuel, is a critical property of fuels, where a knowledge of this value is essential when considering the thermal efficiency of equipment for producing either power or heat. finally, the elemental analyzer (euro ea) used to identify some elements such as carbon, sulfur, hydrogen and nitrogen in material that used during this study and according to astm d5291 and astm d5453. table (2) include all these data. the data obtained from gas chromatograph gc-2010 (shimadzu co.) was used to assess the simulated distillation curves. gas chromatograph was used to carried out identification of compounds. the tests were first conducted with diesel fuel at full-load conditions and the engine speed was changed between 1200 and 2800 rpm at the standard injection pressure of 171 bar with intervals of 200 rpm to obtain the base data of the engine and all these tests were performed under steady state conditions and repeated three times to find the average. the engine was operated after each fuel test, for at least 30 min to consume the fuel which was left in the fuel system from the previous test. the experimental values of the engine performance parameters such as brake specific energy consumption, brake thermal efficiency, exhaust gas temperature, nox emission, unburned fuel emission, carbon monoxide emission and carbon dioxide emission were determined and compared in graphics. engine specification tests were performed using perkins (1006/tag2) generator. the main specifications of the test engine were shown in table (3) . imr1400 exhaust gas analyzer apparatus imr1400 exhaust gas analyzer shown in figure (1), was used to measured hc, co and nox emissions in ppm. the imr1400 unit measures ambient or room temperature, gas temperature, draft pressure, smoke spot o2 and co. all further values, as co2, air free, excess air, efficiency and losses are calculated. also this unit is a comfortable, easy to use flue gas analyzer in robust aluminum case. all accessories needed for measuring are situated inside the case, so that an immediately readiness is guaranteed. to reach the highest accuracy , the analyzer should have an ambient temperature between 10 and 40 ºc [43]. tested parameters al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 222 the specific fuel consumption (sfc) is a function of brake power (pb) and fuel mass flow rate (mf) [44]: ...(1)f b m sfc p   the engine brake thermal efficiency ( ) include some of parameters for comparisons of different fuels, taking into account the effect of differences in the exergy values [45]: ...(2)b f f p m ex    where (exf) is the specific flow exergy of the fuel. also the specific volumetric fuel consumption is possible to express as[44,45]: 1 ...(3) f f svfc ex  where ( f  ) is the fuel density. results and discussion in this paper, the performance and emission characteristics were performed for standard diesel fuel, neat scrap rubber oil and the four blending diesel fuel. performance analysis the brake specific energy consumption (bsec) and brake thermal efficiency for standard diesel fuel, neat scrap rubber oil , and its blend with diesel fuel for different blends of 10, 20, 30, and 40% were calculated for the present engine of the specifications showed in table (2). the results were analyzed and showed graphically in figures (2) and (3). figure (2) shows that, the lower heating value of scrap tire rubber oil made a largely differences in bsec. the resulting increase in required mass fuel flow was needed to obtain similar fuel energy input. at all loads, the brake specific energy consumption of scrap rubber oil blends was 7–20% greater than that of standard fuel and these results may be related to the differences in heating and density between scrap rubber oil and standard fuel. also, brake thermal efficiency was 2-16% lower for scrap rubber oil and other blends. brake thermal efficiency decreases with increasing percentage of scrap rubber oil, figure (3). this may be related to the needy combustion characteristics of these blends due to their high viscosity and low volatility. exhaust gas temperature. figure (4) shows the temperature of exhaust gas variation with respect to the load. the reason of increasing the temperature of exhaust gas with increasing percentage of scrap rubber oil in the blends may be related to the turnout of constituents with higher effervescence points in scrap rubber oil than in standard fuel. not adequately evaporated constituents having higher effervescence points were during the main combustion stage and continued to the late combustion as a result of the heavy constituents. the lower thermal efficiency was resulted in a higher temperature of exhaust gas of 2-15%. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 201 analysis of emission emission of nitrogen oxides (nox) figure (5) showed the divergence of nox emission for different blends with respect to the load. the higher combustion temperature increase nox emissions with the engine load. this proves that the temperature of combustion is the most effective factor for the emissions of nox in the cylinder of engine. from figure (5), it can be seen that the nox emissions from scrap tire rubber oil and its blends are lower than those of standard fuel. about 25-40% reduction of the nox emission was reported for all loads. this is may be due to the lower value of heating of scrap rubber oil. emission of nox is the most hurtful gaseous emissions. unburned emission figure (6) showed that, the unburned fuel emission for scrap rubber oil and its blends were higher than those of diesel fuel except (stro 20) blend where lower by 10 % and 30% compared with the standard diesel and neat scrap rubber oil at full load respectively. the emissions of hydrocarbon fuels may be greatly affected the physical properties of the fuel such as viscosity and density. and cause an increase certain ratios of the fuel blends increase the proportion of the production of hydrocarbons (hc), which affects the quality of the fuel spray. where it is increasing the size of the mixture of fuel droplets, which affect the performance of the combustion process and thus the performance of the engine. we can note that the fuel mixture ratios of 10% and 20% may have given the best results in comparison with the highest ratios in addition to the standard were decreased 2-00% lower than the standard at full load respectively. these results were attributed to the sensitivity of the change in a fuel viscosity. carbon monoxide emission the results of mixing diesel fuel with low rates of scrap tire rubber oil give better results compared with the high mixing ratios, as well as in comparison with the standard fuel. figure (7) shows a reduction in emissions of carbon monoxide by 20% and 50% of the mixing ratios of 10% and 20% respectively. while causing high mixing of the scrap rubber fuel oil with the standard rates of a significant increase in the production of this gas. also, high mixing ratios of scrap tire rubber oil caused a decline in the quality and performance of the engine as has been discussed previously. carbon dioxide emission the co2 emission as expected, increases with an load increasing. figure (8) compares the co2 emissions of various scrap rubber diesel blends. the emissions of co2 of diesel fuel were the higher compared with the other. the carbon content in scrap rubber oil diesel blends at the similar load in the same volume was lower; so, the emissions of co2 from scrap rubber oil and these blends were lower than of standard diesel. because of the incomplete combustion the plants can absorb unwanted emissions of co2 ensures nappy on a balanced its level in the atmosphere. conclusions al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 200 the engine power output and fuel consumption of the engine for the blends compared with those of standard diesel were almost not different when engine work with lower scrap rubber blends of oil diesel. the present experimental tests showed a comparison for the engine run on scrap rubber blends of oil diesel with that of standard. at all loads, bsec of scrap rubber oil blends was 7–20% greater than the standard. additionally, brake thermal efficiency was 2-16% lower for scrap tires rubber oil and its blends, where it decreases with increasing of scrap rubber oil. so, the differences in heating value and density between scrap rubber oil and standard fuel may be caused these results. the lower thermal efficiency was resulted in a higher exhaust temperature of gas of 2-15%. due to the lower heating value of scrap rubber oil, about 3-40% reduction of the nox emission was reported for all loads. the unburned fuel emission for scrap rubber oil and its blends were higher than those of standard fuel except (stro 20) blend where lower by 10 % and 30% compared with the standard diesel and neat scrap rubber oil at full load respectively. also carbon monoxide emission (co) at full load were 20 % and 50% lower than that of standard diesel and neat scrap rubber oil respectively. the co2 emission increases with load increasing and this may be related to the incomplete combustion. it can maintain the level of co2 through photosynthesis performed by plant, where the level of this gas kept in balance in the atmosphere. finally, the results extracted from the current study considered the scrape tire rubber oil 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[42] g. kasiraman, b. nagalingam, m. balakrishnan, performance, emission and combustion improvements in a direct injection diesel engine using cashew nut shell oil as fuel with camphor oil blending, energy 47 (2012) 116-124. [43] exhaust gas analyzer user’s manual. [44] andre valente bueno, josé antonio velásquez, luiz fernando milanez, heat release and engine performance effects of soybean oil ethyl ester blending into diesel fuel, energy 36 (2011) 3907e3916, doi:10.1016/j.energy.2010.07.030. [45] hindren a. saber, ramzi r. ibraheem al-barwari, ziyad j. talabany, effect of ambient air temperature on specific fuel consumption of naturally aspirated diesel engine, journal of science and engineering vol. 1 (1), 2013, 1-7. table (1): standard specifications of diesel oil. properties diesel fuel flash point 50c specific gravity 0.84 carbon residue 0.15 or less cetane value 50 up colour 4 or less pour point 10c calorific value kcal/kg 10170 sulpher % 1.2 or less kinematics viscosity cs 2.7 distillation point 350c table (2): analysis of scrap tires rubber oil. properties scrap rubber oil flash point, closed cup, 0 c, 28 ash, % mass 3.15 moisture 1.20 fixed carbon 24.25 gross calorific value (gcv),mj kgk -1 40.27 specific gravity, g.cm -3 0.86 viscosity, cst (at 40 0 c) 3.28 elemental analysis (n, h, c) nitrogen, (ppm) 0.67 hydrogen, (ppm) 9.86 carbon, (ppm) 82.91 sulfur, (ppm) 0.92 al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 202 table (3): the main specifications of the test engine. make superstar cylinder number 6-vertical in line cylinders type direct injection bore/stroke 94.2 mm/125 mm stroke four stroke compression ratio 18:1 cooling system water cooled generating set model -pl150 150 kva prime power, 16.5 kva standby power a) b) figure (1): (a) the flue gas analyzer unit (imr 1400). (b) the gas flow through the flue gas analyzer unit (imr 1400), al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 202 figure (2): consumption of the brake specific energy. figure (3): brake thermal efficiency. figure (4): exhaust gas temperature. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 202 figure (5) : the variation of nox emission. figure (6): hydrocarbons (unburned fuel) emission. al-qadisiyah journal for engineering sciences, vol. 9……no. 2 ….2016 202 figure (7): carbon monoxide emission. figure (8): carbon dioxide emission. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 525 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. experimental investigation on direct evaporative air cooler performance with cellulosic pads alaa ruhma al-badri, mechanical engineering department, college of engineering, university of wasit, wasit, iraq. email: albadria@uowasit.edu.iq received on 5 october 2017 accepted on 31 october 2017 published on 15 february 2018 doi: 10.30772/qjes.v10i4.502 abstract: evaporative cooling is an economic and environment-friendly technique for air cooling. this technique may involve air cooling with humidification (direct evaporative cooling) or sensible air cooling only (indirect evaporative cooling). in this study, the saturation efficiency of direct evaporative cooling (dec) was investigated with rigid media cellulose (rmc) pads and compared with that of wood straw pads. face air velocity on pads was varied between 0.5 and 3.0 m·s -1 . the time change of ambient air dry-and wetbulb temperatures, water temperature, and outlet air dry-bulb temperature were measured. for cellulosic pad, the experimental data showed that the saturation efficiency reached 71% of its steady state value in the first 100 seconds of operation and the final steady state value was reached after 600 seconds. the saturation efficiency decreases with the increase in the air velocity. it could be shown that the dec is more efficient with wood straw pads compared to rmc pads. predicted data using the published literature underestimated the saturation efficiency of dec by about 18%. keywords: rmc pads, wood straw pads, evaporative cooling, saturation efficiency, adiabatic saturation. introduction direct evaporative air coolers are wildly used in dry and hot weather regions because they are simple in design, saving in power, and friendly to environment. as a result of the remarkable increase in the energy consumption and the continuous depletion of natural energy recourses, evaporative cooling technique is considered to be a potential and promising alternative to mechanical-refrigeration air cooling systems. there are two different techniques for evaporative cooling which are direct and indirect depending on the contact method between air and water. for the indirect evaporation, the two fluids exchange sensible heat via a heat exchanger walls without affecting the air moisture content. in direct evaporation cooling, air is cooled by water evaporation only during a humidification process. the humidification process occurs in a cooling medium (pad) which provides cross flow passages. water drops to bottom of the pad due to gravity while air flow crosses the direction of water flow. the performance of direct evaporative cooling is dependent on operating and configuration parameters. the operating parameters include the weather condition, water inlet temperature, and air-water mass flow rate ratio. the configuration parameters may comprise the size, mailto:albadria@uowasit.edu.iq al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 526 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. geometry, and material of the pad and the cooler case. the effectiveness of dec is determined experimentally by the saturation efficiency ε. iwb,idb, odb,idb, tt tt    .... (1) where tdb,i is the intake air dry-bulb temperature (dbt), tdb,o is the outlet air dbt, and twb,i is the air wet-bulb temperature (wbt) at inlet. the saturation efficiency is dependent on the difference between inlet dbt and wbt which is defined as the wet-bulb depression. dec method may not satisfy human thermal comfort criteria [1] when the wet-bulb depression is relatively small because the performance of dec is affected by the weather condition [2]. evaporative cooling can be also used as a pre-cooler [3], in a hybrid mode with air conditioning systems [4], and to enhance the condenser performance of refrigeration systems [5] and air cooled chillers [6].the efficiency of the evaporative cooler is related to the ability of the pads to absorb water and to provide large contact area for heat and mass transfer between air and water. thus, the efficiency of the cooler is mainly dependent on the pad type. researcher pay considerable efforts to develop efficient pads made of local materials. therefore, cooler pads may be fabricated from different materials such metal, wood straw, plastic [7], pvc sponge mesh [8], and coconut fiber [9]. in the recent years, rigid media cellulose (rmc) pads have been widely used as a cooling media for evaporation cooling because they are characterized by regular shape, compactness, wide range of types and geometries. the saturation efficiency can be also theoretically predicted by [10]          ap,a cexp1 cm ah   .... (2) where is the mass flow rate of air, hc is the heat transfer coefficient, a is the wetted surface area, and cp,a is the specific heat of humid air. for rmc pads, the following correlation can be used to calculate hc [11] 3/18.012.0 c prre)(1.0 l l h e ....(3) where l is the thickness of pad and lc is the characteristic length which is defined by a v l c ....(4) and v is the volume of rmc pad. the objective of the present study is to investigate the performance of a direct evaporative cooler with rmc pads under normal operating weather condition. the influence of air velocity is taken into al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 527 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. consideration. the saturation efficiency of dec with rmc pads is compared with that with wood straw pads of the same dimensions. 1. experimental setup the performance of direct evaporative cooler was experimentally measured using the experimental setup shown in figure 1 and the experiments were achieved in the laboratories of engineering college/wasit university. this setup is mainly consisted of an evaporative cooler and a measuring system. the evaporative cooler was made of metal sheets in form of small box of size (50×50×52) cm 3 with three removable doors. each door contains 3cm thickness rmc pad of (32×32) cm 2 face area. the wetted area of pads is 539 m 2 per unit volume and the inclination angle of air passages is about 42º. figure 2 shows images for the investigated rmc and wood straw pads. a centrifugal fan was mounted inside the cooler box to draw ambient air through the rmc pads. for variable air velocity, the fan speed was controlled by a pulse-width-modulation (pwm) electronic card of 500 watt maximum power. a small electric submerged water pump circulates the water from the cooler sump to the upper edge of the pads. this enables cross contact between dripped water and the drawn air through the pads. a duct of square cross section of (24×24) cm 2 and 100 cm length was installed at the outlet of the cooler. measured parameters were the dbt and wbt of air at inlet (ambient air) and at the outlet duct, water temperature of the cooler sump, and air velocity at the outlet duct. volumetric water flow rate was kept constant during the experiments. the face air velocity of pads uf can be determined by: f d df a a uu  …. (5) where ud is the air velocity in the duct outlet, ad is the cross section area of the duct, and af is the face area of pads. shielded thermistors ntc 10kω were used for temperature measurements. for the wbt, the thermistor was wrapped by a wetted cotton wick. an electronic sensor was used for air velocity measurements. this sensor operates with 5 volts supply voltage while the output voltage of the sensor represents the air velocity. a formula was provided by the manufacturer to interpret the output voltage into air velocity. the sensors were installed as shown in figure 1. a data logger labjack t7 pro was used for the data acquisition with a user interface achieved by labview software student edition 2011. for each experimental run, the steady state condition was observed. this can be ensured when the water temperature of the sump is being very close to the wbt of air. after reaching the steady state, 100 samples for each measured quantity are recorded by the data logger. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 528 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 1: experimental setup. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 529 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: images of rmc and wood straw pads. the uncertainty in the saturation efficiency uε is evaluated using the multi-samples uncertainty analysis method [12] which depends on the determination of systematic (fixed) and random errors for each measured quantity (measurand). accordingly, uε is determined by the following equation 2/1 1j 1j 2 jr, j 2 jf, j δδ                                     n n t t t t u   ….(6) where δtf,j and δtr,j are systematic and random errors for temperature tj, and n is the number of temperatures. the saturation efficiency ε can be considered to be a function of temperatures only, see eq. (1). then the sensitivity of ε with respect to tdb,i, tdb,o, and twb,i are expressed by  2iwb,idb, iwb,odb, idb, tt tt t      …. (7) iwb,idb,odb, 1 ttt      …. (8) and  2iwb,idb, odb,idb, iwb, tt tt t      …. (9) the random error can be determined for each parameter by the following equation [12] m s t 2 δ r  ….(10) where s is the standard deviation of the recorded samples and m is the number of samples. for a confidence level of 95%, the value of m corresponds to 100 samples according to the “t” table. the systematic error is, equal to 1%, provided by the manufacturer of the thermistors. the uncertainty limit in the temperature measurements and air velocity were ±0.5°c and ±11.6%, respectively. the saturation efficiency al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 530 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. was very sensitive to the change in the wbt compared to dbt. this can be shown by eq. (9) where the wbt exists only in denominator and the difference between dbt and wbt is squared leading to a significant influence on the results when wbt changes. for the saturation efficiency, the uncertainty limit of the experimental data was ±4.5%. 2. results and disscusion in this study, the saturation efficiency of dec was experimentally investigated with rmc pads. time change of temperatures for air and water were recorded. the impact of air velocity and wet-bulb depression on the saturation efficiency was investigated. a comparison was made between experimental and predicted data. in addition, the saturation efficiency with rmc pads was compared with that of wood straw pads. figure 3: time change of temperatures. figure 3 shows the time change of intake (ambient) dbt and wbt (tdb,i and twb,i), water temperature (tw), and the outlet dbt (tdb,o). the water volumetric flow rate and the face air velocity of pads were 1.7 lit·min -1 and is 1.2 m·s -1 respectively. the change in the ambient temperatures was relatively small during this experiment. the outlet dbt decreases sharply with the time until it approaches the steady state condition where the change in the temperature with time becomes very small. the water temperature decreases also with time but with a slower rate than the outlet air. therefore the time required to reach the steady state for water (tw) is longer compared to that for the outlet dbt (tdb,o). this time period is dependent on the water amount in the cooler sump. at steady state, the wbt is higher than the water temperature. this al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 531 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. may due to the parasitic heat transfer from ambient to wet-bulb sensor which increases the sensor reading [13]. however, the difference is within the uncertainty limit of the temperate measurements. the time change of the measured saturation efficiency (ε) is shown in figure 4.the value of ε was determined using eq. (1). at time equals zero, the pad was completely dry. the adiabatic efficiency increases linearly with time, then the rate of increase slows gradually, and finally reaches to the steady state condition. the time response of ε is close to the exponential form. the saturation efficiency reached 71% of the maximum value in 100 seconds and the final steady state saturation efficiency was reached after 600 seconds. figure 4: the saturation efficiency as a function of wet-bulb depression. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 532 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the performance of dec with wood straw and rmc pads was experimentally investigated. air velocity in the outlet duct was varied between 2 and 13 m·s -1 . this range corresponds to face velocity on the pads between 0.5 and 3.0 m·s -1 . the face air velocity is determined using the air volumetric flow rate with the face area of pads. the ambient dbt was between 35.5 and 33 ºc. during the experiments, the wbt was between 20ºc and 19.2 ºc. figure 5 shows a comparison between experimental and predicted saturation efficiency as a function of air face velocity for rmc pads. the experimental data were determined using eq. (1) while the predicted values were based on eq. (2). the saturation efficiency decreases with the increase in the air velocity. this may be because of the increase in the inlet mass flow rate of air which results in a decrease in the moisture fraction in the outlet air, and then increasing the outlet dbt. experimental data are higher than predicted one for all experimental runs. this may be a result of assumptions that was previously made for eq. (2) that ignored the effect of latent heat of water evaporation. however, eq. (2) underestimated the saturation efficiency by about 18% for the measured range of air velocity. figure 5: comparison between experimental and predicted saturation efficiency versus air velocity for rmc pads. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 533 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 6 shows the saturation efficiency of dec as a function of face air velocity for rmc and wood straw pads. the saturation efficiency of dec with wood straw pads is higher than that with rmc pads for the air velocity range between 0.5 and 3.0 m·s -1 . for low velocity, the evaporative cooler performance is slightly affected by the pad type. for all data points, wood straw pads are more efficient than rmc pads. this may due to differences in material specifications such as the ability of material to absorb water. the effectiveness of pads is mainly dependent on the ability of pad material to absorb water and to mix both water and air together for exchanging heat and water vapor. however, this is also affected by the pad’s thickness. for the present study, the rmc pad thickness is only 3cm which is close to the thickness of wood straw pads. figure 6: experimental saturation efficiency versus air velocity for wood straw and rmc pads. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 534 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. conclusions the saturation efficiency of direct evaporative cooling (dec) was experimentally investigated with rmc pads and compared with that of wood straw pads. face air velocity was varied between 0.5 and 3.0 m·s -1 . transient temperature change and the saturation efficiency were recorded using a data acquisition system. from this study, it could be shown that the saturation efficiency reached 71% of its steady state value in the first 100 s and the final steady state value was reached after 600 s. eq. (2) [10] underestimated the effectiveness by about 18% for the measured range of air velocity. the saturation efficiency decreases with the increase in the air velocity. the effectiveness of dec with wood straw pads was higher than that with rmc pads of the same dimensions. list of symblos a area, m 2 cp specific heat, kj·kg -1 ·k -1 l pad thickness, m lc characteristic length, m m mass flow rate, kg·s -1 pr prandtl number re reynolds number s standard deviation t temperature, k u uncertainty v pad volume, m 3 greek symbols ε saturation efficiency subscripts db dry-bulb d duct f face area of pads i inlet o outlet w water wb wet-bulb abbreviations dec direct evaporative cooling dbt dry-bulb temperature rmc rigid media cellulose wbt wet-bulb temperature biodata dr. alaa ruhma al-badri studied the phd (dr. -ing.) at the erlangen-nuremebrg university (germany), lecturer at the engineering college / wasit university. research intersts include refrigeration and air conditioning, heat engineering and solar systems. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 535 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. refrences 1. j.r. camargoa, c.d. ebinumab, s. cardosoa, three methods to evaluate the use of evaporative cooling for human thermal comfort, engenharia térmica (thermal engineering), 5 (2006 ) 09-15. 2. j.m. wu, x. huang, h. zhang, theoretical analysis on heat and mass transfer in a direct evaporative cooler, applied thermal engineering, 29(5–6) (2009) 980-984. 3. y. chen, h. yang, y. luo, parameter sensitivity analysis of indirect evaporative cooler (iec) with condensation from primary air, energy procedia, 88 (2016) 498-504. 4. v. jain, s.c. mullick, t.c. kandpal, a financial feasibility evaluation of using evaporative cooling with air-conditioning (in hybrid mode) in commercial buildings in india, energy for sustainable development, 17(1) (2013) 47-53. 5. p. martínez, j. ruiz, c.g. cutillas, p.j. martínez, a.s. kaiser, m. lucas, experimental study on energy performance of a split air-conditioner by using variable thickness evaporative cooling pads coupled to the condenser, applied thermal engineering, 105 (2016) 1041-1050. 6. x. hao, c. zhu, y. lin, h. wang, g. zhang, y. chen, optimizing the pad thickness of evaporative aircooled chiller for maximum energy saving, energy and buildings, 61 (2013) 146-152. 7. a. malli, h.r. seyf, m. layeghi, s. sharifian, h. behravesh, investigating the performance of cellulosic evaporative cooling pads, energy conversion and management, 52(7) (2011) 2598-2603. 8. c.-m. liao, k.-h. chiu, wind tunnel modeling the system performance of alternative evaporative cooling pads in taiwan region, building and environment, 37(2) (2002) 177-187. 9. j.k. jain, d.a. hindoliya, experimental performance of new evaporative cooling pad materials, sustainable cities and society, 1(4) (2011) 252-256. 10. j.r. camargo, c.d. ebinuma, j.l. silveira, experimental performance of a direct evaporative cooler operating during summer in a brazilian city, international journal of refrigeration, 28(7) (2005) 11241132. 11. j.a. dowdy, n.s. karabash, experimental determination of heat and mass transfer co-efficients in rigid impregnated cellulose evaporative media, ashrae transaction, 93 (part 2) (1987) 382–395. 12. r.j. moffat, describing the uncertainties in experimental results, experimental thermal and fluid science, 1(1) (1988) 3-17. 13. j.p. brenner, design specifications for wet-bulb aspirator apparatus, master thesis, university of wisconsin-madison, 2010. template for academica science journal journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 229 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. removal of a chemical dye from wastewater using low cost agro-based adsorbents: continuous adsorbers hatem asal gzar, assistant prof. dr./civil eng. department/ college of engineering/ wasit university. e mail: hatam_asal@yahoo.com noor qassim sabri, civil eng. department/ college of engineering / wasit university. e mail: engnoorqassim@yahoo.com abstract: natural materials that are readily available in large amounts in nature and easily accessible may be used as low cost additives. the aim of this study is to measure the susceptibility of these locally available materials, conocarpus plant, to improve the quality of wastewater discharged from textile industry. in addition to conocarpuswithout chemically treated, conocarpuschemically treated, carbonized conocarpus and activated carbon were used as adsorbents in order to make a comparison, and to test which one of the four types give the best efficiency for removing dye. the ability of adsorbents to adsorb dye was studied using continuous system; studied parameters were effect of flow rate, bed depth, and initial concentration. the experimental results showed that maximum removal efficiency of conocarpus without chemically treated was found to be 90% after 75 min at flow rate 20 l/h, ph value 3 , bed depth 5cm and initial concentration 40 mg/l. the maximum removal efficiency for conocarpus chemically treated was up to 83.75% after 15 min at flow rate 10 l/h, ph value 3, bed depth 10 cm and initial dye concentration 40 mg/l. the maximum removal efficiency for carbonized conocarpus was up to 99.67% after 15 min at flow rate 10 l/h, ph value 3, bed depth 10 cm and initial dye concentration 40 mg/l. for activated carbon the maximum removal efficiency was found to be 99.75% after 15 min at flow rate 10 l/h, ph value 3, bed depth 10cm and initial dye concentration 40 mg/l. keywords: terasil blue dye, wastewater, treatment, low cost adsorbent, continuous study. introduction the process of removing dyes and industrial wastes, is one of the major worldwide natural issues. and that textile manufacturing and dyeing is one of the processes that produce wastewater in large amounts. wastewater-equipped textiles contain a residue treatment bath from preparation,dyeing, finishing, reduction, and other processes (korbahti 2007). wastes from textile and dyeing industry cause serious environmental damage to adjacent aquatic particle because of presence of hazardous chemical dyes , dark coloring and chlorine residues (asamudo et al., 2005 ; senel et al., 2012). mailto:hatam_asal@yahoo.com journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 230 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. many chemical, physical and biological processes have been used, such as image oxidation and adsorption processes, to remove the chemical dyes used in the dyeing process. at all times, the adsorption process is used to collect chemical dyes on a solid matrix before biological and chemical treatments (ozmihci and kargi, 2006; aydın et al., 2007). one of the materials used as a adsorbent is activated carbon powder although its high price but is the most effective material used to remove organic compounds because of large area (1000 m2 g-1) and its high ability to absorb (karthikeyan and mohan, 1997; kestioglu and yalili, 2006; ozer and akdemir, 2013) . many kinds have been studied of agricultural crops to dispose of dye from sewage like mud produced by the sugar industry (magdy and deifullah, 1998) , rice husk (mackay et al., 1986), peel of orange ( namasivayam et al., 1996) and other agricultural crops like wood (mackay et al., 1998), cassava peels and kenaf (hussein et al., 2016) in this study, conocarpus plant was used as absorbent material to remove the terasil dye from kut textile plant, it is have fast growing and available in large quantities and easy to obtain. 1. experimental procedure and methods 1.1 source of wastewater solution was prepared by dissolving (40) mg of terasil blue dye in 1000 ml of a tap water, this concentrations of solution will be used for all experiments. the dye components (table 1) were examined using eds device (type x – act , usa) .the measurements were conducted at the central service laboratory college of education ibn alhaitham, university of baghdad. table 1. the components in terasil blue dye element weight% atomic% c 37.45 50.29 o 35.52 35.81 na 9.89 6.94 s 8.52 4.29 cl 3.72 1.69 br 4.90 0.99 totals 100 100 1.2 adsorbents in this study, four absorbent substances were used conocarpus-without chemically treated, carbonized conocarpus, conocarpus after chemically treated, and activated carbon. 1.3 physical properties of adsorbents physical properties of conocarpus plant ,carbonized conocarpus and activated carbon have been measured such as solubility, specific surface area, bed porosity, bulk density, real density, pore volume and pore size. the measurements were conducted at ministry of oil / petroleum research & development center, journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 231 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. baghdad . physical properties of the conocarpus, carbonized conocarpus and activated carbon are illustrated in table (2) . table 2. physical properties of adsorbent materials: conocarpus , carbonized conocarpus and activated carbon. properties conocarpus carbonized conocarpus activated carbon color green black black appearance powder powder powder odors odor odorless odorless solubility insoluble in water insoluble in water insoluble in water specificsurface area(m2/g) 0.1217 83.387 732.6352 bed porosity 0.526669 0.822401 0.815945 bulk density (g/cm3) 0.7117 0.3723 0.4123 real density(g/cm3) 1.5036 2.0963 2.2401 pore volume (cm³/g) 0.000542 0.078202 0.540373 pore size (nm) 17.82860 3.75131 2.95030 1.4 characterization of adsorbents figures (1), (2) and (3) show the outer surface and surface morphology of the conocarpus , carbonized conocarpus and activated carbon particles respectively using scanning electron microscope sem (type ais2300, usa). the measurements were conducted at the central service laboratory college of education ibn alhaitham, university of baghdad. figure 1. sem micrograph of conocarpus. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 232 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 2. sem micrograph of carbonized conocarpus. figure 3. sem micrograph of activated carbon. 1.5 preparation of the adsorbents preparation of the adsorbent materials; conocarpus -without chemically treated, conocarpus-after chemically treated and carbonized conocarpus are illustrated below. 1.5.1 preparation of conocarpus-without chemically treated conocarpus leaves was taken from the campus of wasit university to be used in this study. the previous studies (hussein et al., 2016) were adopted as a working method for preparation of conocarpus. plant leaves washed three times by using distilled water to get rid of any dust. after finishing washing, it is dried in the oven at 110 ° c for 3 hours; then grinded in a mill to a small volume of less than 500 microns. the last step of the preparation process is sieving through (150 -300) μm. figure (4) shows the preparation of conocarpus adsorbent. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 233 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 4. preparation of conocarpus adsorbent. 1.5.2 preparation of carbonized conocarpus the previous studies (ramadan et al., 2005) were adopted as a working method for carbonization of conocarpus plants. the following steps illustrate the preparation of carbonized conocarpus: 1. cutting the plant into small pieces. 2. washing it three times with distilled water to clean it. 3. dry it at 110 oc for three hours and repeat the drying step for other quantities until the required quantity is obtained. 4. the dried plant is grinded into small granules using grinder. 5. 1: 0.5 of the conocarpus and sodium hydroxide are mixed well. 6. put the mixture in oven at temperature 300 oc for half an hour with continuous flipping 7. raise the temperature to 500 oc for an hour and a half. the total time for carbonization process was two hours. 8. wash the product in the filtration device twice with distilled water and then washed with hydrochloric acid at a concentration of 10% once to remove the effect of base solution then wash it with water once to remove acidic excitation. 9. the product is then dried in oven at 110 ° c for three hours, then grinded into small granules. 10. sieving the product through (150-300μm). conocarpus, carbonized conocarpus, after preparation are shown in figure (5) journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 234 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 5. conocarpus-without chemically treated and carbonized conocarpus, materials used as adsorbents in the present study. 1.5.3 preparation of conocarpuschemically treated several experiments were conducted to pull the color of the conocarpus. the best result was obtained using the following procedure: 1. cutting plant leaves. 2. washed three times with distilled water to get rid of any dust. 3. dried in the oven at 110 ° c for 3 hours. 4. grinded in a mill to a small volume of less than 500 microns. 5. wash the product again in the filtration device twice with distilled water. 6. put the product in solution of hydrochloric acid at a concentration of 10% for a full day then wash it with water once to remove acidic excitation. 7. wash the product again in the filtration device with hydrogen peroxide then wash it with water once to remove hydrogen peroxide excitation. 8. dried in the oven at 110 ° c for 3 hours. 9. grinded in a mill to a small volume of less than 500 microns. 10. the last step of the preparation process is sieving through (150 -300) μm. figure (6) shows conocarpusafter chemically treated. conocarpus-without chemically treated carbonized conocarpus journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 235 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 1.6 activated carbon powder activated carbon pac (german origin) as shown in figure(7) was used as adsorbent in the experiments. pac specifications are shown in table (3). table 3. specifications of activated carbon. specification value mw 12.01 g/mol soluble in water <0.2% soluble in hcl < 1% soluble in c2h5oh < 0.2% chloride cl <0.001% cooper cu <0.05% iron fe <0.002% lead pb <0.001% journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 236 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 7. activated carbon 1.7 experimental work the schematic equipment for experimental representation is shown in figure (8). 1.8 system structure and equipment requirements a. 80-liter cylindrical steel tank for preparation of terasil blue dye solution. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 237 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. b. 30 liter container for liquid waste collection. c. column made of glass material with an internal diameter of 50 mm and height of 1000. d. pvc flanges and various sizes of hoses and pipes joined together by different fittings. e. flow meter to measure flow rate (0 30 l/ h). f. pump of maximum capacity of 50 liters / hour. g. gate valves are used to control the flow in the system. h. two sampling points were selected, first from the top of the fluidized column and the other before the feeding tank. 1.9 experimental procedure a the adsorbent was placed in adsorption column to the required bed depth. b-the terasil blue dye solution with the desired concentration was prepared in the cylindrical steel tank, using tap water. cthe terasil blue dye solution was adjusted to ph 3 using naoh or hcl. dthe terasil dye solution was pumped into the absorption column through the flow meter at the required flow rate. esamples were taken periodically; the concentration of terasil dye was measured using uv device (type irprestige-2; shimadzu 8000, japan). fthe break through curves were determined by plotting (ce/co) with time. the experimental conditions are shown in table (4). table 4. experimental conditions of the experiments used in the present study. adsorbents conocarpus-without chemically treated , conocarpuschemically treated ,carbonized conocarpus and activated carbon adsorbate terasil bed depth, cm 5 ,7.5 , 10 flow rate, (l/h) 3 , 10 ,20 initial concentration (mg/l) 40,70,140 temperature, oc 20 oc ± 1 particle size, mm (150 – 300) micron ph 3 2. results and discussion journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 238 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2.1 effect of flow rate the effect of flow rate on the adsorption process in fluidized bed column was investigated. breakthrough curves were obtained at different flow rates 3, 10, and 20 l/h at initial concentration 40 mg/l and bed depth 5 cm, as shown in figures (9), (10) and (11) . figure 9. breakthrough curves for terasil dye adsorption onto activated carbon at different flow rates, 20 , and ph 3. 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0 50 100 150 c e /c o time , min q =3 l/l q = 10 l/h q = 20 l/h figure 10. breakthrough curves for terasil dye adsorption onto carbonized conocarpus at different flow rates, 20 , and ph 3 journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 239 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 11. breakthrough curves for terasil dye adsorption onto conocarpus after chemically treated at different flow rates, 20 , and ph 3. when the adsorbent; activated carbon , carbonized conocarpus and conocarpus after chemically treated; were used at flow rates 10 l/h and 20 l/h, the breakthrough curves occurred rapidly with increasing flow rate because the dye had less time to contact with absorbent materials that led to the removal of less dye figures (9), (10) and (11). the breakthrough period increased significantly with a decrease in flow. absorption becomes smaller with increased hydraulic load due to reduced contact time between dye and absorbent materials. with high flow rate, ce /co increase rapidly. compared to a fixed bed column it did not have this speed because the surface area of the absorbent material is limited in the fixed bed due to the dead zone that appear between the particles. these results are consistent with the results obtained by wang et al., (1997). at low flow rate 3 l/h the dispersion velocity of the absorbent materials and dye is low, so their kinetic energy becomes less and the attractiveness of the dye molecules decreases. therefore, the adsorption process is less efficient when discharge is very low. when the concarpus-without chemically treated was used as adsorbent, a quick absorption of the terasil blue dye occurred as the flow rate decrease (figure 12). the breakthrough curves have reached a breakthrough state with remarkable speed at low flow rate. this is because the low flow rate the greater contact time for the solution with sorbent , and the more time lead to the plant's susceptibility to give the green color, because of the plant did not undergo to carbonization process or chemically treated. figure 12. breakthrough curves for terasil dye adsorption onto conocarpuswithout chemically treated at different flow rates, 20 , and ph 3 journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 240 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. by comparing the three adsorbent to investigate the effect of the flow rate 3 l / h on the adsorption process, it is shown that carbonized conocarpus is more effective in the process of adsorption where the maximum efficiency of removal 93.75%, followed by activated carbon where the maximum efficiency of removal 86,75 % . for the conocarpus after chemically treated, the maximum efficiency of removal was 59.6 %, and for the conocarpus-without chemically treated the maximum efficiency of removal was 25 %. at flow rate 10 l/h, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 99.44%, followed by carbonized conocarpus where the maximum efficiency of removal 95.45%. for the conocarpus after chemically treated the maximum efficiency of removal was 80.72 % and for the conocarpus –without chemically treated the maximum efficiency of removal was 75 %. at flow rate 20 l/h, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 99.4%, followed by carbonized conocarpus where the maximum efficiency of removal 95.25%, for the conocarpus –without chemically treated the maximum efficiency of removal was 90%, and for the conocarpus after chemically treated the maximum efficiency of removal was 75.77%. 2.2 effect of bed depth from figures (13) , (14) and (15) the slope of the breakthrough curve at a bed depth of 10 cm is lower than that of 7.5 cm and 5 cm. when the bed depth increases, the removal efficiency increases. in the higher depth, more terasil dye pull out from the solution compared to the lower depth. it also shown that the curved slope of breakthrough curves less in fluidized bed compared to a fixed bed because of the presence of dead zone that appear in the hard bed. these conclusions are similar to those obtained by han et al, (2006). -0.002 0 0.002 0.004 0.006 0.008 0.01 0.012 0 50 100 c e /c o time ,min l = 10cm l = 7.5 cm l = 5 cm figure 13. breakthrough curves for terasil dye adsorption onto activated carbon, at different bed depths, 20 , and ph 3. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 241 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0 50 100 c e /c o time ,min l = 10 cm l = 7.5 cm l = 5 cm figure 14. breakthrough curves for terasil dye adsorption onto carbonized conocarpus, at different bed depths, 20 , and ph 3. 0 0.05 0.1 0.15 0.2 0.25 0.3 0 50 100 c e / c o time ,min l = 10 cm l = 7.5 cm l = 5 cm figure 15. breakthrough curves for terasil dye adsorption onto conocarpus after chemically treated, at different bed depths, 20 , and ph 3. figure 16. breakthrough curves for terasil dye adsorption onto conocarpus-without chemically treated, at different bed depths, 20 , and ph 3. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 242 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. from figure (16) when the bed depth increases the effectiveness of a adsorption process decreases, because of increasing the ability of conocarpus plant to give the color. by comparing among the adsorbents, the effect of the bed depth on the efficiency of the adsorption process was investigated. at 10 cm depth it is shown that activated carbon and carbonized conocarpus were more effective in the process of adsorption where the efficiency of removal 99.75 % and 99.67%, respectively. while the maximum removal of efficiency of conocarpus-after chemically treated was 83.75%, and the maximum removal of efficiency of conocarpus was 60%. at the bed depth 7.5 cm, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 99.48%, followed by carbonized conocarpus where the maximum efficiency of removal 98.75 %, while the maximum removal of efficiency of conocarpus after chemically treated was 82.25%, and for the conocarpus plant the maximum efficiency of removal was 67%. at bed depth 5 cm, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 99.44%, followed by carbonized conocarpus where the maximum efficiency of removal 95.45%. while the maximum removal of efficiency of conocarpus after chemically treated was 80.72%, and for the conocarpus plant the maximum efficiency of removal was 75%. 2.3 effect of initial concentration figures (17) to (20) show the effect of initial concentration of dye on the shape of breakthrough curves. three initial concentrations 40, 70 and 140 mg/l were adopted in the fluidized bed column experiments. whenever the initial concentration increases, the more likely the penetration curves are obtained. at the highest initial concentration of terasil blue dye, the absorbent bed is exhausted in the shortest time and this leads to early breakthrough. this has a decrease in the stop point with increased concentration of the dye where the link sites are quickly saturated in the column. the curved slope of breakthrough curves less in fluidized bed compared to a fixed bed because of the presence of dead zone in fixed bed. by comparing among the adsorbents, at initial concentration 40 mg/l, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 99.44%, followed by carbonized conocarpus where the maximum efficiency of removal 95.45%. while the maximum removal of efficiency of conocarpus after chemically treated was 80.72%, and for the conocarpus the maximum efficiency of removal was 75%. at initial concentration of terasil dye 70 mg / l, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 94.14%, followed by carbonized conocarpus plant where the maximum efficiency of removal 93%. while the maximum removal of efficiency of conocarpus after chemically treated was 71.42%, and for the conocarpus plant the maximum efficiency of removal was 21.4%. at initial concentration of terasil dye of 140 mg / l, it is shown that activated carbon is more effective in the process of adsorption where the maximum efficiency of removal 89.28 %, followed by carbonized conocarpus where the maximum efficiency of removal 82.14 %. while the maximum removal of efficiency of conocarpus after chemically treated was 65%, and for the conocarpus plant the maximum efficiency of removal was 13%. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 243 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 50 100 150 c e /c o time , min co = 40 mg /l co = 70 mg/l co = 140 mg/l figure 17. breakthrough curves for dye biosorption onto activated carbon , at different initial concentrations, 20 , and ph 3. 0 0.1 0.2 0.3 0.4 0.5 0 20 40 60 80 c e /c o time , min co = 40 mg/l co = 70 mg/l co = 140 mg/l figure 18. breakthrough curves for terasil dye adosorption onto carbonized conocarpus, at different initial concentrations, 20 , and ph 3. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 244 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 50 100 c e / c o time ,min ce = 40 mg/l ce = 70 mg/l ce = 80 mg/l figure 19. breakthrough curves for terasil dye adosorption onto conocarpus after chemically treated, at different initial concentrations, 20 , and ph 3. figure 20. breakthrough curves for terasil dye adsorption onto conocarpus without chemically treated , at different initial concentrations, 20 , and ph 3. conclusion 1. it is found that the breakthrough curves depend on the physiochemical properties of the absorbent material such as the composition of the feeding solution, the operation column, the initial concentration, bed depth, and flow rate. 2. it is observed that when the bed depth of conocarpus chemically treated ,carbonized conocarpus plant and activated carbon increased, the adsorption process becomes more efficient, either in case of the use of conocarpus without chemically treated, when the depth of bed increases the adsorption process decrease 3. when use conocarpus chemically treated, carbonized conocarpus plant and activated carbon , it is shown that the time needed to reach the breakpoint decreases with the flow rate increasing, but in journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 245 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. the case of the use of conocarpus without chemically treated the time we need to reach the break point increases with the increase in flow rate. 4. note that the time needed to reach the break point decreases with the increase of initial concentration of the terasil blue dye. refrences 1. akdemir eo and ozer a (2013). pretreatment of cheese whey effluent using a microfiltration process: a statistical design approach. ekoloji 22(88): 21-27. 2. asamudo nu, daba as and ezeronye ou (2005). bioremediation of textile effluent using phanerochaetechrysosporium. african journal of biotechnology 4: 1548-1553. 3. aydin s, güneysu s and arayici s (2007). investigation of using adsorbents obtained from sewage sludge with pyrolysis for removal of cod and dye from textile industry wastewater. ekoloji 16(64): 4348. 4. mckay g (1998). kinetic models for the sorption of dye from aqueous solution by wood. process safety and environmental protecttion 76b: 183-191. 5. han, r., zou, w., li, h., li, y. and shi, j., (2006). copper(ii) and lead(ii) removal from aqueous solution in fixed-bed columns by manganese oxide coated zeolite , journal of hazardous materials, b137, 934-942. 6. hussein m (2016). removal of methylene blue dye from synthetic wastewater using low cost agro-based adsorbents m sc. thesis, college of engineering, university putra malaysia. 7. korbahti bk (2007). response surface optimization of electrochemical treatment of textile dye wastewater. journal of hazardous materials 145: 277-286. 8. kestioglu k and yalili m (2006). treatability of textile industry wastewater with high cod content by chemicalprecipitation and adsorption. ekoloji 15(59): 27-31. 9. magdy yh and daifullah aam (1998). adsorption of a basic dye from aqueous solutions onto sugarindustrymud in two modes of operations. waste managment 18: 219-226. 10. mckay g, ramprasad g and pratapamowli p (1986). equilibrium studies for the adsorption of dyestuffs from aqueous solution by low-cost materials. water air soil pollution 29: 273-283 11. mohan sv and karthikeyan j (1997). removal of lignin and tannin colour from aqueous solution by adsorption onto activated charcoal. environmental pollution 97: 183-187. 12. namasivayam c, muniasamy n, gayatri k, rani m and ranganathan k (1996). removal of dyes from aqueous solutions by cellulosic waste orange peel. bioresource technology 57: 37-43. 13. ozmihci s and kargi f (2006). utilization of powdered waste sludge (pws) for removal of textile dyestuffs from wastewater by adsorption. journal of environmental management 81(3): 307-314 14. ramadan a, ghazal r and jarges k (2005). preparation of activated carbon from cocustree residues using modified carbonate and chemical thermal activating, qatar journal of chemistry 18,161-169 15. senel u, sur hi, demirtas m (2012). investigation of mutagenic effects of some synthetic reactive dyes in textile industry by using umu-test. ekoloji, 21(85): 49-56. 16. wang, r.c, kuo, c.c. and shyu , c.c., (1997). adsorption of phenols onto granular activated carbon in a liquid.solid fluidized bed , j. chem. tech. biotechnol, 68, 187-194. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 115 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. numerical investigation of microchannel heat sink with mepcm suspension with different types of pcm mushtaq ismael hasan*, mechanical engineering department, college of engineering, thi-qar university mushtaq76h@gmail.com hind lafta tbena, mechanical engineering department, college of engineering, thi-qar university hindlafta88@gmail.com received on 11 january 2018 accepted on 8 april 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.524 ________________________________________________________________________________ abstract: the aim of this paper is to study the microencapsulated phase change materials (mepcm) suspension as a coolant instead of pure fluid in the micro channel heat sink (mchs) with different core and wall materials as well as different base fluids. the mepcm suspension using in this study consist of microcapsules constructed from n-octadecane, rt44 as a phase change materials (pcm) and shell materials are poly-methylmthacrylate (pmma), poly-alpha olefin (pao), these capsules are suspended in (pure water, ethylene glycol and pure oil) in a concentration of (0–20)% and have been used as a cooling mediums at different ambient temperatures. constant heat flux is applied at base of heat sink. the results obtain show that, using mepcm suspensions as a coolant in micro heat sink instead of conventional cooling with pure fluid lead to enhance the cooling performance of micro heat sink is be 20.91% with (rt44+pmma) pure oil, 16.91% with (rt44+pmma) for ethyleneglycol and 12.91% with (rt44+pmma) for pure water at concentration 2% and 𝑉𝑖 = 0.28 m/s. the phase change material in mepcm suspension should be select according to its melting temperature corresponding to the certain application since different mepcm suspension concentration caused different values of reduction in heat sink temperature in range of ambient temperature due to different in its melting temperatures. ________________________________________________________________________________ keywords: micro-channel heat sink, heat sinks, microencapsulated phase change materials, mepcm suspension, phase change materials mailto:mushtaq76h@gmail.com mailto:hindlafta88@gmail.com al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 116 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. nomenclature: symbol description si unit symbol description si unit a cross-sectional area 𝑚2 u fluid x-component velocity m/s c volume fraction % v fluid y-component velocity m/s 𝐶𝑝 specific heat capacity (j/kg k) w fluid z-component velocity m/s h channel height m 𝑊𝑐𝐻 channel width m h heat transfer coefficient w/𝑚2. k x axial coordinate m ∆h latent heat w y vertical coordinate m 𝐻𝑒 enthalpy of suspension w z horizontal coordinate m 𝑆𝐻 sensible heat w ρ density kg/𝑚3 k thermal conductivity w/m k μ dynamic viscosity 𝑚2/s l length m φ mass fraction m mass flow rate kg/s β melting fraction ∆p pressure drop pa abbreviation 𝑚. flow rate 𝑚3/𝑠 v volume q heat transfer rate w hs heat sink t thickness m ch channel ntroduction micro-channels heat sinks are used in the cooling of electronic devices since it can extract a large quantity of heat for a small region, because of its ability to absorb heat generated in devices. cooling fluids used in micro-channels heat sinks are establish an important part of cooling applications, and physical properties for these fluids used are affect the cooling capacity. using mepcm suspensions is more activate due to their abilities of enhancement performance of thermal energy storage and convection heat transfer. this heat transfers improvement due to latent heat absorption through the melting process by the pcm al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 117 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. suspended of mepcm particles. there are many researchers in literature who studied the performance of micro-channels heat sink and the use of micro-encapsulated phase change materials suspensions. rami s. et al. (2008)[1] numerically investigated the use of microencapsulated phase change materials suspension in heat transfer of fluid to improve the presentation of micro-channel heat sink. they used three dimensional geometric model to invent the flow and heat transfer in the suspension. the microencapsulated contains of phase change materials (rt44) and which have a specified variety of temperature of solidify and melt. the heat flux applied on the base is (100-500) 𝑊/𝑐𝑚2 and the dimensions of the micro-channel heat sink are 5.1mm width, 1.5mm height and length of 10mm. the micro-channel heat sink consists of 25 equally space of rectangular channels each with 100μm width, 500μm depth and 10mm length. wall thickness for the channels separated by a 100μm and made from aluminum for the same material of heat sink. their results indicated that, due to using these microencapsulated the specific heat capacity, thermal conductivity and fluid effective are enhanced due to latent heat effect and micro-mixing respectively. mushtaq i. hasan (2011)[2] numerically investigated the micro channel heat exchanger with microencapsulated phase change material suspension in counter flow. the mepcm suspension contains of microcapsules constructed from the shell material is poly methyl methacrylate and n-octadecane as a phase change material. the concentration of these capsules suspended in water are (0-20)%. he found that, using of mepcm suspensions led to increase the pressure drop and modify thermal presentation of a counter flow micro channel heat exchanger with increasing its effectiveness. samira m. and samad s.(2014)[3] numerically investigated the latent heat of thermal energy storage methods. they studied the influence mepcm slurry on temperature of the hot and cold fluids. they used different volumes fractions of mepcm slurry. thermal boundary condition applied on the bottom wall of a heat sink is a constant heat flux of 100 𝑊/𝑐𝑚2. their results indicated that, by using mepcm at 25% volume fraction indications to the enhancement in fluid temperature that is, the rate of rise temperature for cold fluid decreases to 9% and the rate of reduction temperature for hot fluid increases up to 23.5%, related to using water only in the microelectronic mechanical system. samad s. and samira m. (2015)[4] numerically investigated the enhancement thermal performance of a micro-channel heat sink by using nanoencapsulated phase change material (nepcm) suspension as a cooling fluid replace of pure fluid. a three dimensional model of a rectangular channel by using nepcm suspended in water was developed. the pcm is n-octadecane (nepcm core) and polystyrene (nepcm wall). the inlet temperature is equal to 300 k, inlet velocity is 1m/s and the melting range used for pcm is 300-500 k. they analyzed the nepcm is suspended in water in a concentration of (020) %. their results presented a significant decrease in wall temperature of heat sink and the mean temperature of fluid along the channel below a definite condition for the heat flux amounts that depends on the inlet velocity and volume fraction of the nepcm suspension. mushtaq i. hasan (2017)[5] numerically investigated for improving the cooling performance of electrical distribution transformer using transformer oil – based mepcm suspension. the volume concentration as a coolant fluid in place of pure transformer oil is (5-25)%. the phase change material used in his study is paraffin wax (𝐶20 𝐻42) to manufacture the suspension. he found that, when using of mepcm suspension in place of pure transformer oil lead to enhance the cooling performance of mepcm suspension and transformer by decreasing its temperature. xu han et al. (2017)[6] experimentally studied a new microencapsulated phase change material. in their study they used organic phase change material (n-octadecane) as a core and poly methyl methacrylate as a shell. their results indicated that the range of the mean diameter is (2–3) μm, by a uniform distribution size, and the phase change temperature is 26.2 c° and enthalpy of microencapsulated phase change material is 139.68 j/g. their results showed that at (2 to 3) mm thick covering containing of microencapsulated phase change material the amplitude temperature decreased by (5-6) c° and power monitoring for the period of the higher temperature indicated that in one day the time startup of air condition expectedly decreased, thus saving electric consumptions about 26%. nathan s. et al. (2017)[7] experimentally investigated and provided a technique of heat transfer development using microencapsulated phase change material suspension. they tested two types of microcapsules pcm al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 118 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (metal coated and non-metal coated) were tested during a short tube micro channel heat exchanger by different fluid flow rates and different concentrations (5 and 10 wt.%)pcm. they found that ℎ𝑓 is increased by 3.5 times compare with pure water when the ratio 10% of non-metal covered mpcm slurry which used. the metal covered mpcm slurry presented a further 10% increasing in ℎ𝑓 related to the non-metal covered at same reynolds number and mpcm concentration. somayeh l. et al. (2017)[8] experimentally investigated the effect of shell flexibility on the encapsulation efficiency and thermal performance of the microcapsules. the series of microcapsules, containing n-hexadecane (hd) as the core, and polymethyl methacrylate (pmma) and poly(butyl acrylate-co-methyl methacrylate) (poly(ba-co-mma)) as the shells were prepared through suspension polymerization. their results showed that, thermal properties of the microcapsules were estimated by differential scanning calorimetry (dsc) and dynamic mechanical thermal analysis (dmta) was performed to evaluate the rigidity of shells with two distinct t𝑔𝑆 for poly(ba-co-mma). 1-encapsulation of pcms: the development of using encapsulation increases the heat transfer coefficient and heat transfer area of the system. it is also considerate in forming a protecting and obstruction the pcm from the controlling the volume changes and outside surrounding of the pcm. encapsulated pcms are collected of shell is inorganic material or polymer and pcms as a core to obtain the required shape of encapsulated also prevents pcm through phase change process from leakage. the encapsulated pcms dependent on the size, are classified in to micro pcms, macro pcms and nano pcms. the size of macro pcms is larger than 1 mm, the size of nano pcms is smaller than 1 μm and micro pcms usually varies from 1 μm to 1 mm. due to the influence like reduction of the pcms reactivity through outside surrounding, increase in area of the heat transfer and establishment for the resist changes in size to core material of the pcm, such as the phase change happens they have involved significant importance in the ranges of energy storage similar solar energy storage application, thermo-regulated foams and fibers, energy-saving of building materials, etc. [11]. 2problem description: the physical model studied of the problem is shown in fig.1.a which represents the micro channel heat sink (mche) which consists of rectangular channel and the flow is consider single phase. the length of the micro channel heat sink is 20mm, width 200μm and height 100μm. flow in this model is developing and conjugating heat transfer where the 3d governing equations used for solving this model are continuity, momentum and energy requisite be solved of the two solid and fluid wall instantaneously. due to the thermal symmetry and geometrical between rows of micro channel’s, a heat sink unit consists of one channel shown in fig.1.b will be used for solving and representing the complete heat sink. figure 1:.a schematic of micro channel heat sink figure.1.b schematic of micro channel heat sink unit base inlet outlet x y z al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 119 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3mathematical model: 3-1governing equations: the governing equations which are represented by continuity, momentum and energy used for pure fluid and suspension are the same. the governing equations can be written as following [2, 9, 10, 11]: the continuity equation: 𝜕𝑢 𝜕𝑥 + 𝜕𝑣 𝜕𝑦 + 𝜕𝑤 𝜕𝑧 = 0 (1( momentum equations: 𝑢 𝜕𝑢 𝜕𝑥 𝑣 𝜕𝑢 𝜕𝑦 + 𝑤 𝜕𝑢 𝜕𝑧 = − 1 𝜌 𝜕𝜌 𝜕𝑥 + 𝜇 𝜌 ( 𝜕2𝑢 𝜕𝑥2 + 𝜕2𝑢 𝜕𝑦2 + 𝜕2𝑢 𝜕𝑧2 ) (2) 𝑢 𝜕𝑣 𝜕𝑥 𝑣 𝜕𝑣 𝜕𝑦 + 𝑤 𝜕𝑣 𝜕𝑧 = − 1 𝜌 𝜕𝜌 𝜕𝑦 + 𝜇 𝜌 ( 𝜕2𝑣 𝜕𝑥2 + 𝜕2𝑣 𝜕𝑦2 + 𝜕2𝑣 𝜕𝑧2 ) (3) 𝑢 𝜕𝑤 𝜕𝑥 𝑣 𝜕𝑤 𝜕𝑦 + 𝑤 𝜕𝑤 𝜕𝑧 = − 1 𝜌 𝜕𝜌 𝜕𝑧 + 𝜇 𝜌 ( 𝜕2𝑤 𝜕𝑥2 + 𝜕2𝑤 𝜕𝑦2 + 𝜕2𝑤 𝜕𝑧2 ) (4) energy equation: 𝜌𝐶𝑝(𝑢 𝜕𝐻𝑒 𝜕𝑥 + 𝑣 𝜕𝐻𝑒 𝜕𝑦 + 𝑤 𝜕𝐻𝑒 𝜕𝑧 ) = 𝑘( 𝜕2𝑇 𝜕𝑥2 + 𝜕2𝑇 𝜕𝑦2 + 𝜕2𝑇 𝜕𝑧2 ) (5) the enthalpy of the suspension (h𝑒) is described by eq. (6) and calculated from sum quantity of the sensible heat (sh) and the latent heat (∆h) of the pcm h𝑒 = sh + ∆h (6) the sensible heat is defined by eq. (7), where ℎ𝑟𝑒𝑓.is the reference enthalpy at 𝑇𝑟𝑒𝑓. ℎ𝑒 = ℎ𝑟𝑒𝑓.+ ∫ 𝐶𝑃𝐹 𝑇 𝑇𝑟𝑒𝑓. dt (7) the latent heat (∆h) of the slurry is defined by eq. (8) as a function of the mepcm mass fraction (φ), latent heat of fusion of the pcm (l) and melted mass fraction (β). the melted mass fraction (β) is defined as the mass ratio of melted pcm to the total mass of pcm in the slurry. the pcm start to melt at 𝑇𝑠𝑜𝑙𝑖𝑑𝑢𝑠 and completing melting at 𝑇𝑙𝑖𝑞𝑢𝑖𝑑𝑠 where the liquid fraction can vary from 0 at 𝑇𝑠𝑜𝑙𝑖𝑑𝑢𝑠 to 1 at 𝑇𝑙𝑖𝑞𝑢𝑖𝑑𝑠 eq. (9), which is known as the lever rule, describes the melted mass fraction (β). ∆h = β φ l (8) where: β = 0 if 𝑇𝑓 < 𝑇𝑠𝑜𝑙𝑖𝑑𝑢𝑠 β = 0 if 𝑇𝑓 > 𝑇𝑙𝑖𝑞𝑢𝑖𝑑𝑠 β = 𝑇𝑓 − 𝑇𝑠𝑜𝑙𝑖𝑑𝑢𝑠 𝑇𝑓 − 𝑇𝑙𝑖𝑞𝑢𝑖𝑑𝑠 if 𝑇𝑠𝑜𝑙𝑖𝑑𝑢𝑠< 𝑇𝑓 < 𝑇𝑙𝑖𝑞𝑢𝑖𝑑𝑠 (9) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 120 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 3-2model boundary conditions the boundary conditions used to close the mathematical model are: 1no slip at wall u = v = w = 0. 2constant heat flux at the bottom wall, q = qin. 3insulated top wall of micro channel heat sink unit. 4symmetry b.c at the right and left sides of micro channel heat sink unit. 5inlet and outlet uniform v= 𝑉𝑖 , t= 𝑇𝑖 . 6fully developed flow at the end of channel (stagnation pressure = 0). 7no slip conjugate heat transfer between interface fluid solid. 4spesification of microcapsules: mepcm particles consist of polymers surrounding a core of pcm. the polymer wall is flexible sufficiently to arrange for accommodations volume changes that complemented by solid/liquid phase change. fig.2 shows a single mepcm particle which is consists of two parts: the outer polymer is shell material and the inner phase change material and moving interface between solid and liquid pcm. the inspected mepcm particles which have average diameter is 5μm has been investigation. two shell materials are studied (poly-methyl-methacrylate (pmma), poly-alpha-olefin (pao)) with the core materials are (n-octadecane and rt44). the core material (pcm) is about 70% by volume in a single mepcm particle. there are more important factors which are governed by chosen of the suspending fluid, its compatibility with pcms and the microcapsule wall therefore the physical properties of the wall material and pcms are different. the properties of the mepcm must be calculated from the properties of the different components. the mass and energy balance correspondingly can be used to calculated density and specific heat of the microcapsules. 𝜌𝑃𝐶𝑀 = 10 7 ( 𝑑𝑐 𝑑𝑃𝐶𝑀 )3 𝜌𝐶 (10) solid pcm liquid pcm polymer shell moving interface figure 2: sketch of single mepcm particle during melting al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 121 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 𝐶𝑃𝑃𝐶𝑀= ( 7𝐶𝑝𝑐 + 3 𝐶𝑝𝑤𝑎𝑙𝑙) 𝜌𝑐 𝜌𝑤𝑎𝑙𝑙 (3 𝜌𝑐 + 7 𝜌𝑤𝑎𝑙𝑙) 𝜌𝑃𝐶𝑀 (11) the calculation of thermal conductivity of the microcapsules by using compound sphere approach is given by: 1 𝐾𝑃𝐶𝑀 𝑑𝑃𝐶𝑀 = 1 𝐾𝐶 𝑑𝑐 + 𝑑𝑃𝐶𝑀 − 𝑑𝑐 𝐾𝑤𝑎𝑙𝑙 𝑑𝑃𝐶𝑀 𝑑𝑐 (12) 5properties of suspension: the properties of the suspension are a mixture of the properties of the microcapsules and suspending fluid. the density and specific heat are calculated by using mass and energy balance [2, 5, 11, 12]. 𝜌𝑓 = 𝐶𝜌𝑃𝐶𝑀+ ( 1𝐶) 𝜌𝑊 (13) 𝐶𝑃𝐹 = φ 𝐶𝑃𝑃𝐶𝑀 + (1φ) 𝐶𝑝𝑤 (14) where φ is the mass fraction which can be calculated by: φ = 𝐶𝜌𝑃𝐶𝑀 ( 𝜌𝑤+𝑐( 𝜌𝑃𝐶𝑀− 𝜌𝑤)) = 𝐶𝜌𝑃𝐶𝑀 𝜌𝑓 (15) the viscosity of the suspension was calculated from the relation: 𝜇𝑓 = 𝜇𝑤 (1 – c – 1.16 𝐶 2)−2.5 (16) this relation has been presented to be effective for concentration up to 20% and mean particle diameter of 0.3 400 μm and ratio of channel-to particle diameter of 20 – 100. to calculate the thermal conductivity of suspension following relationship was used: kf = 2𝑘𝑤 + 𝑘𝑃𝐶𝑀 +2𝐶( 𝐾𝑝𝑐𝑚 –𝑘𝑤) 2+ 𝐾𝑃𝐶𝑀 𝑘𝑤 – 𝐶 ( 𝑘𝑃𝐶𝑀 𝐾𝑤 −1) (17) to calculate the performance of heat sink is ratio of heat transfer to the pumping power we use: ƞ = 𝑞 𝑝.𝑝 (18) where p.p is the pumping power: p.p = ∆p. 𝑚. (19) pressure drop is equal to: ∆p = 𝑝𝑜𝑢𝑡 𝑝𝑖𝑛 (20) flow rate is equal to: 𝑚.= a .v (21) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 122 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the mepcm suspension concentration used in this paper were (2%, 5%, 10%, 15% and 20%). table1 shows the thermo-physical properties of studied materials [11,12]. table 1 physical properties of suspension components [11,12] material ρ(𝑘𝑔/𝑚3) 𝐶𝑝(j/kg k) k(w/m k) μ(kg/m s) pure water ethylene glycol transformer oil rt44 (rubitherm) (pcm) n-octadecane (pcm) pmma (mepcm wall) pao (mepcm wall) 981.3 1111.4 870 771 solid = 850 liquid = 780 1190 783 4189 2415 2000 2000 2222 1470 2242 0.643 0.254 0.109 0.2 0.358 0.21 0.143 0.000598 0.0157 0.0124 _ _ _ _ 6numerical solution: a finite volume method (fvm) is used to find solutions of governing equations and boundary conditions of the above system numerically. computing fluid dynamics (cfd) has been model to solve the numerical model. simple algorithm is used to solve the problem of coupling to computing the flow variables by solving the continuity, momentum, energy equations. the mesh is chosen for solving the system by recognizing grid size since a mesh refinement has been made to find suitable mesh size that give a high accurate solution. fig. 3 shows the model flow chart for numerical solutions by using cfd. table 2 shows the different meshes selected and from this table it can be seen that, the solution becomes independent of mesh size after the fourth mesh, therefore the fourth mesh will be used for all next solutions. the convergence conditions used to control the numerical solution is 10-6 for both energy and momentum equations. table 2 grid independent study mesh size outlet temperature (k) mesh1 (interval size = 0.0005) 314.4 mesh2 (interval size = 0.0004) 314.5 mesh3 (interval size = 0.0003) 314.78 mesh4 (interval size = 0.0002) 314.17 mesh5 (interval size = 0.00015) 314.02 mesh6 (interval size = 0.0001) 314 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 123 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 7rusults and discussions: 7-1validation: to check the validity of used numerical model, this model is validated with numerical model presented in [1]. the numerical model presented in [1] is micro-channel heat have vertical height 1.5 mm, length 10mm and width 5.1mm. the mepcm water slurry is analyzed with volume fraction of 0% (pure water), 5%, 10%, 15%, 20% and 25%. for this study the temperature was measured in the base of heat sink, at the boundary conditions applied on this model at different inlet temperature of 25c°, inlet velocity 1m/s and constant heat flux of 100 𝑊/𝑐𝑚2 subjected on the bottom wall of the model for the different models of designs. fig.4 shows the comparison between the numerical results of [1] and results of present model for the temperature along the bottom wall of heat sink. it can be noted from this figure that the agreement between results is acceptable where the maximum error is 0.96%. yes start geometry meshing fluent solving post processing validation data analysis end no figure 3:model flowchart al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 124 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 7-2results: in this study, a 3-d micro-channel heat sink with the rectangular channel and mepcm suspension is numerically investigated. computing fluid dynamics (cfd) has been code to solve the numerical code. firstly, the model is solved with pure water, secondary the model is solved with ethyleneglycol and last the model is solved with pure oil as a cooling fluids with constant properties selected according to the ambient temperature, then the solution is repeated with using mepcm suspension with different concentrations as a cooling medium instead of pure fluids. different types of mepcm core and wall have been simulated to find out the best case which gives higher performance and cooling of heat sink. figures (5a and 5b) indicate the contours for temperature at cross sectional plan at z = 0.002m and top longitudinal plan at y=0.00015m for pure water (base case). from figure 4.a it can be seen that, the temperature is decreased from the solid walls of heat sink toward the surface the channel, due to absorption of heat by pure water as a results of heat transfer process and transferring the heat to the environment by convection and radiation. for figure 4.b it can be noted that, the temperature of water is increased along flow direction due to heat transfer from lower wall with constant heat flux. fig.4 variation of base temperature along microchannel heat sink as comparison between result of [1] of present model for pure water 299 300 301 302 303 304 305 306 307 308 309 310 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 b a se t e m p e ra tu re ( k ) x / l numerical results of [1] results of present model figure 5:a cross sectional contour of static temperature for heat sink with pure water at t=25c° al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 125 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. fig.6 illustrated the variation of base temperature with ambient temperature for the micro channel heat sink unit filled with pure water (base case) at concentration 0% and mepcm suspension for different concentration at 2%, 5%, 10%, 15% and 20%. from this figure it can be seen that, the base temperature increased with increasing the ambient temperature for all materials used due to decreased in temperature difference and as results decreased in amount of the heat can be transferred from heat sink. when increasing concentration of mepcm suspension decreased base temperature therefore base temperature at concentration 20% gives a lower temperature compare with other concentration of mepcm suspension. from this figure it can be noted that, the temperature of heat sink decreased by using mepcm suspension compared with pure water (base case) because the mepcm can absorbs added heat as a latent heat due to melting process. for this figure used (rt44) mepcm core with pmma (mepcm wall) for all materials above the core material (pcm) in a single mepcm particle is about 70% by volume. figure 5:b longitudinal contour of static temperature for heat sink with pure water at t=25c° 298 303 308 313 318 323 328 333 338 343 348 295 300 305 310 315 320 325 330 335 340 b a se t e m p e ra tu re ( k ) ambient temperature (k) pure water (c=0%) mepcm (c=2%) mepcm (c=5%) mepcm (c=10%) mepcm (c=15%) mepcm (c=20%) figure 6: variation of base temperature with ambient temperature of pure water and rt44 with pmma suspension at different concentrations al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 126 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. fig. 7 expresses the variation of temperature reduction with ambient temperature for micro channel heat sink unit when filled with pure water (base case) at concentration 0% and mepcm suspension for different concentration at 2%, 5%, 10%, 15% and 20%. from this figure it can be distinguished prominently that, the temperature reduction decreased with increasing the ambient temperature due to decreased in temperature difference and as results decreased in amount of the heat can be transferred from heat sink according to the relationship 𝑇𝑅 = 𝑇𝑤𝑖𝑡ℎ 𝑜𝑢𝑡 𝑃𝐶𝑀 – 𝑇𝑤𝑖𝑡ℎ 𝑃𝐶𝑀 𝑇𝑤𝑖𝑡ℎ 𝑜𝑢𝑡 𝑃𝐶𝑀 ∗ 100%. it is noticeable that from this figure, the temperature reduction of heat sink for concentration of mepcm suspension at 20% of the mepcm core (rt44) with pmma (mepcm wall) gives high temperature reduction compared with other concentration due to properties of pcm and mepcm wall. fig. (8, 9, 10 and 11) show the variation of base temperature with heat flux for the micro channel of heat sink unit when filled with mepcm suspension at a concentration 2%. these figures reveal that, the base temperature increased with increasing the heat flux values applied on the base of heat sink and mepcm suspension at 2% for pure water gives lower base temperature compare with ethyleneglycol and pure oil due to decreased in the temperature of mepcm suspension and other properties compare with temperature of other pure fluids according to the relationship tr = twith out pcm – twith pcm twith out pcm ∗ 100%. for figure 9 its can be observable that, the mepcm core (rt44) with pao (mepcm wall) for pure water gives a lower temperature compare with other figures due to properties of pcm (rt44) lower density, specific heat and thermal conductivity compare with pcm (n-octadecane) has high density, specific heat and thermal conductivity, and the properties of pao (mepcm wall) high specific heat, lower density and thermal conductivity compare with pmma (mepcm wall) has high density and thermal conductivity. 0.09 0.11 0.13 0.15 0.17 0.19 0.21 0.23 0.25 295 300 305 310 315 320 325 330 335 340 r e d u ct io n t e m p e ra tu re ambient temperature (k) mepcm (c=2%) mepcm (c=5%) mepcm (c=10%) mepcm (c=15%) mepcm (c=20%) figure 7:variation of temperature reduction with ambient temperature for pure water and rt44 with pmma of suspension at different concentrations al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 127 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figures (12, 13, 14 and 15) display the variation of temperature reduction with heat flux for the micro channel of heat sink unit when filled with mepcm suspension at concentration at 2%. from these figures it is clear that, the temperature reduction increased with increasing the heat flux values applied on the base of heat sink. form figure 13, it is obvious that, the mepcm core (rt44) with pao (mepcm wall) for pure water give a lower temperature compare with other figures due to properties of pcm (rt44) lower density, specific heat and thermal conductivity compare with pcm (n-octadecane) has high density, specific heat and thermal 300 305 310 315 320 325 330 335 340 555 565 575 585 595 605 615 625 635 645 b a se t e m p e ra tu re ( k ) heat flux (w/m2) (n-oct.+pmma)for pure water (n-oct.+pmma)for ethylene glycol (n-oct.+pmma)for pure oil fig. 10 variation of base temperature with heat flux for n-octadecane with pmma at a concentration 2% 300 305 310 315 320 325 330 335 340 555 565 575 585 595 605 615 625 635 645 b a se t e m p e ra tu re ( k ) heat flux (w/m2) (n-oct.+pao)for pure water (n-oct.+pao)for ethylene glycol (n-oct.+pao)for pure oil fig. 11 variation of base temperature with heat flux for n-octadecane with pao at a concentration 2% 300 305 310 315 320 325 330 335 340 555 565 575 585 595 605 615 625 635 645 b a se t e m p e ra tu re ( k ) heat flux (w/m2) (rt44+pmma)for pure water (rt44+pmma)for ethylene glycol (rt44+pmma)for pure oil fig. 8 variation of base temperature with heat flux for rt44 with pmma at a concentration 2% 300 305 310 315 320 325 330 335 340 555 565 575 585 595 605 615 625 635 645 b a se t e m p e ra tu re ( k ) heat flux (w/m2) (rt44+pao)for pure water (rt44+pao)for ethylene glycol (rt44+pao)for pure oil fig. 9 variation of base temperature with heat flux for rt44 with pao at a concentration 2% al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 128 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. conductivity, and the properties of pao (mepcm wall) high specific heat, lower density and thermal conductivity compare with pmma (mepcm wall) has high density and thermal conductivity. the concentration of mepcm suspension at 2% gives lower temperature reduction of pure water compare with ethyleneglycol and pure oil according to the relationship tr = twith out pcm – twith pcm twith out pcm ∗ 100%. fig.16 represents a distribution of nussle number along micro channel heat sink unit filled with pure water (base case) at concentration 0% and mepcm suspension for different concentration at 2%, 5%, 10%, 15% and 20%. for this figure used (rt44) mepcm core with pmma (mepcm wall), and for all concentration at a constant inlet temperature, when increasing length of channel the nussle number decreasing almost on the regular shape due to regular in the temperature distribution along channel and when increased length the temperature increasing since performed that to output temperature higher from input temperature, nussle number decreasing with decreasing heat transfer coefficient(h). from this figure it can be distinguished that, the mepcm suspension at concentration 20% gives higher value of nussle compare with 0.02 0.12 0.22 0.32 0.42 0.52 0.62 0.72 0.82 0.92 1.02 1.12 555 565 575 585 595 605 615 625 635 645 t e m p e ra tu re r e d u ct io n ( k ) heat flux (w/m2) (rt44+pmma)for pure water (rt44+pmma)for ethylene glycol (rt44+pmma)for pure oil figure 12: variation of temperature reduction with heat flux for rt44 with pmma at a concentration 2% 0.02 0.12 0.22 0.32 0.42 0.52 0.62 0.72 0.82 0.92 1.02 1.12 555 565 575 585 595 605 615 625 635 645 t e m p e ra tu re r e d u ct io n ( k ) heat flux (w/m2) (rt44+pao)for pure water (rt44+pao)for ethylene glycol (rt44+pao)for pure oil figure 13: variation of temperature reduction with heat flux for rt44 with pao at a concentration 2% 0.02 0.12 0.22 0.32 0.42 0.52 0.62 0.72 0.82 0.92 1.02 1.12 555 565 575 585 595 605 615 625 635 645 t e m p e ra tu re r e d u ct io n ( k ) heat flux (w/m2) (n-oct.+pmma)for pure water (n-oct.+pmma)for ethylene glycol (n-oct.+pmma)for pure oil figure 14:variation of temperature reduction with heat flux for n-octadecane with pmma at a concentration 2% 0.02 0.12 0.22 0.32 0.42 0.52 0.62 0.72 0.82 0.92 1.02 1.12 555 565 575 585 595 605 615 625 635 645 t e m p e ra tu re r e d u ct io n ( k ) heat flux (w/m2) (n-oct.+pao)for pure water (n-oct.+pao)for ethylene glycol (n-oct.+pao)for pure oil figure 15:variation of temperature reduction with heat flux for n-octadecane with pao at a concentration 2% al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 129 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. pure water give lower value along the channel due to properties of suspension (temperature, specific heat, thermal conductivity and other properties) decreased when increasing concentration therefore decreasing temperature and give high nussle number, in pure water inverting happen due to higher properties. fig.17 explains the variation between heat transfer from heat sink and heat flux applied on the base when the heat sink unit filled with pure water at c = 0% and mepcm suspension (rt44 with pmma) at a concentration 2%, 5%, 10%, 15% and 20%. from this figure it can be seen that, heat transfer increased with increasing heat flux and pure water give high value of heat transfer due to the increase in heat transfer coefficient (h). when increased concentration, the heat transfer from heat sink decreasing therefore mepcm suspension at a concentration 20% gives lower value of heat transfer from the heat sink due to decreasing in the properties of suspension at the concentration 20%. 260.5 290.5 320.5 350.5 380.5 410.5 440.5 470.5 500.5 530.5 560.5 590.5 555 565 575 585 595 605 615 625 635 645 h e a t tr a n sf e r( w ) heat flux (w/m2) pure water (c=0%) mepcm (c=2%) mepcm (c=5%) mepcm (c=10%) mepcm (c=15%) mepcm (c=20%) figure 17: variation of heat transfer with heat flux for pure water and rt44 with pmma of suspension at different concentrations 400000 430000 460000 490000 520000 550000 580000 610000 640000 670000 700000 0.0005 0.0025 0.0045 0.0065 0.0085 0.0105 0.0125 n u z/l pure water (c=0%) mepcm (c=2%) mepcm (c=5%) mepcm (c=10%) mepcm (c=15%) mepcm(c=20%) figure 16:variation of nusselt number along channel for pure water and rt44 with pmma suspension at different concentrations al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 130 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the variation of total pressure drop with heat flux for micro channel heat sink unit when filled with pure water (base case) at concentration 0% and mepcm suspension for different concentration at 2%, 5%, 10%, 15% and 20% is shown in fig.18. in this figure (rt44) mepcm core is used with pmma (mepcm wall), and it can be observed that, the total pressure drop increased with increasing concentration of mepcm suspension compare with pure water for all values of heat flux and mepcm suspension at concentration 20% gives high pressure drop compare with other concentration and pure water due to properties of mepcm suspension. figures (19, 20, 21 and 22) show the variation of performance of the heat sink with the heat flux for the micro channel of heat sink unit when filled with mepcm suspension at concentration at 2% and inlet velocity 0.28 m/s. from these figures it can be perceived that, the performance of mepcm suspension increased with increasing heat flux for all pure fluid used. from fig.22 (n-octadecane with pmma) give high performance and mepcm suspension for pure oil give high performance compared with ethyleneglycol and pure water due to the increased in value of heat transfer from the pure oil and decreasing pressure drop compared with ethyleneglycol and pure water. 0 5 10 15 20 25 30 35 40 45 50 55 150 250 350 450 550 650 750 850 950 1050 ∆ p ( k p a ) heat flux (w/m2) pure water (c=0%) mepcm (c=2%) mepcm (c=5%) mepcm (c=10%) mepcm (c=15%) mepcm(c=20%) figure 18:variation of pressure drop with heat flux for pure water and rt44 with pmma of suspension at different concentration al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 131 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 7-3conclusion: in this paper using of the mepcm suspension as a cooling fluid instead of pure water, ethylene glycol and pure oil in micro-channel heat sink for cooling of the electronic divides and modify its cooling performance. from the obtained results the following conclusions can be made: 1using of mepcm suspension in heat sink led to reduce heat sink temperature compared with using pure water, ethylene glycol and pure oil. figure 21: variation of performance with heat flux for n-octadecane with pmma of suspension at a concentration 2% and vi = 0.28 m/s 0.0491 0.0691 0.0891 0.1091 0.1291 0.1491 0.1691 0.1891 0.2091 555 565 575 585 595 605 615 625 635 645 p e rf o rm a n ce heat flux (w/m2) (n-oct.+pmma)for pure water (n-oct.+pmma)for ethylene glycol (n-oct.+pmma)for pure oil 0.0691 0.0891 0.1091 0.1291 0.1491 0.1691 0.1891 0.2091 555 565 575 585 595 605 615 625 635 645 p e rf o rm a n ce heat flux (w/m2) (n-oct.+pao)for pure water (n-oct.+pao)for ethylene glycol (n-oct.+pao)for pure oil figure 22: variation of performance with heat flux for n-octadecane with pao of suspension at a concentration 2% and vi = 0.28 m/s 0.0691 0.0891 0.1091 0.1291 0.1491 0.1691 0.1891 0.2091 555 565 575 585 595 605 615 625 635 645 p e rf o rm a n ce heat flux (w/m2) (rt44+pmma)for pure water (rt44+pmma)for ethylene glycol figure 19: variation of performance with heat flux for rt44 with pmma of suspension at a concentration 2% and vi = 0.28 m/s 0.0891 0.1091 0.1291 0.1491 0.1691 0.1891 0.2091 555 565 575 585 595 605 615 625 635 645 p e rf o rm a n ce heat flux (w/m2) (rt44+pao)for pure water (rt44+pao)for ethylene glycol (rt44+pao)for pure oil figure 20: variation of performance with heat flux for rt44 with pao of suspension at a concentration 2% and vi = 0.28 m/s al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 132 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2using this type of suspension n-octadecane (mepcm core) with pmma( mepcm wall) and rt44 (mepcm core) and pao (mepcm wall) led to modify thermal performance of mchs by increasing pressure drop. 3using n-octadecane (mepcm core) with pmma( mepcm wall) and rt44 (mepcm core) and pao (mepcm wall) suspensions as a coolant fluid in micro heat sink instead of pure water, ethylene glycol and pure oil led to enhance the cooling performance of micro heat sink. 4-variation of temperature reduction (tr) decreased with increasing ambient temperature and increased with increasing heat flux for cooling medium studied. 5when using rt44 (mepcm core) and pao (mepcm wall) for suspension give lower temperature reduction (tr) compare with using n-octadecane (mepcm core) pao (mepcm wall) for suspension due to high specific heat, thermal conductivity and lower latent heat of fusion. 6for different applications in electronic devices used micro channel heat sink for a cooling medium from this calculations of different materials its can be noticed that the n-octadecane (mepcm core) with pmma( mepcm wall) for pure water compared with other types give a lower temperature, while rt44 (mepcm core) and pao (mepcm wall) for pure water gives a lower temperature reduction (tr) and gives high performance for pure oil. 7the cooling performance of micro heat sink is be 20.91% with (rt44+pmma) pure oil, 16.91% with (rt44+pmma) for ethyleneglycol and 12.91% with (rt44+pmma) for pure water at concentration 2% and 𝑉𝑖 = 0.28 m/s. references: 1. rami s., mohammed m. farid and said al-hallaj, "micro-channel heat sink with slurry of water with micro-encapsulated phase change material: 3d numerical study", journal of applied thermal engineering, 2008, vol. 29, pg. 445 -454. 2. mushtaq i. hasan, " numerical investigation of counter flow microchannel heat exchanger with mepcm suspension", applied thermal engineering, 2011, vol. 31, pg. 1068-1075. 3. samira m. and samad s., " thermal performance of mems-based heat exchanger with microencapsulated pcm slurry", journal of power and energy engineering, 2014, vol. 2, pg. 15-22. 4. samad s. and samira m., "effect of using nano encapsulated phase change material on thermal performance of micro heat sink", int. j. nanosci. nanotechnol., 2015, vol. 11, no. 1, pg. 33-38. 5mushtaq i. husan, " improving the cooling performance of electrical distribution transformer using transformer oil – based mepcm suspension", engineering science and technology, an international journal, 2017, vol.20, no.2, pg.502-510. 6. xu h., yong l., li y., qiwei w., hua z., huiliang l., guoqing z. and lvming x., "experimental study on effect of microencapsulated phase change coating on indoor temperature response and energy consumption", advances in mechanical engineering, 2017, vol. 9, no.6, pg.1–8. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 133 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 7. nathan s. roberts, refat al-shannaq, jamal k., shaheen a. al-muhtaseb and mohammed m. farid, " efficacy of using slurry of metal-coated microencapsulated pcm for cooling in a micro-channel heat exchanger", applied thermal engineering, 2017, vol. 112, pg.11-18. 8. somayeh l., hassan a., ali r. mahdavian and veronica a., " thermal and morphological studies on novel pcm microcapsules containing n-hexadecane as the core in a flexible shell", applied energy, 2017, vol. 190, pg. 612–622. 9. mushtaq i. hasan, abdul a. rageb, yaghoubi m. , homayony h., "influence of channel geometry on the performance of counter flow micro channel heat exchanger", int. journal of thermal sciences, 2009, vol. 48, pg.1607-1618. 10. mushtaq i. hasan, hayder m. hasan and ghassan a. abid, "study of the axial heat conduction in parallel flow microchannel heat exchanger ", journal of king saud university – engineering sciences, 2014, vol. 26, pg.122–131. 11. rao y., frank d. and peter s., "convective heat transfer characteristics of microencapsulated phase change material suspensions in mini-channels", heat and mass transfer, 2007, vol. 44, pg.175-186. 12. mushtaq i. hasan, abdul a. rageb, yaghoubi m. , homayony h., "investigation of counter flow micr channel heat exchanger performance with using nanofluid as a coolant", journal of electronics cooling and thermal control, scientific research, 2012, vol. 2, pp. 35-43. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 197 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. studying the evaluation of the efficiency of phosphoric acid on the separation of nickel from the waste of south baghdad thermal power station basheer hashem hlihl, middle technical university, institute of technology-baghdad e mail: bashhash66@gmail.com abstract: the process of separating nickel from the waste of thermal power stations has a positive effect on the environment and has a good economic return. . in this study, nickel was separated from the wastes of the south baghdad thermal power station by using phosphoric acid. the investigation studied the influence parameters ( concentration of acid, temperature, time, size of waste granules and acid to the waste quantity ratio) on separation process of nickel. the best conditions in the separation process were obtained when the concentration of acid is 5 molarities, the temperature 50 °c, the duration time of separation is 4 hours, the acid phosphoric to the waste quantity ratio is 30, and the size of the waste granules is 150μm. the percentage of nickel that can be separated from the wastes of south baghdad thermal power station reaches 81%. keywords: south baghdad thermal power station, nickel separating, evaluation of the phosphoric acid introduction nickel is considered a rare element in the soil because its concentration does not exceed 56 mg/kg, its rating 22 in terms of abundance of elements in the crust of earth( 2012 nickel has many important uses, especially in . ،أ.د.شفيق )أ.د.نور الدين و the chemical, steel, paint, money alloyed, computer, jewelry, printing, catalysts, and electrical industries. approximately 700,000 tons of nickel are consumed annually (cunningham et al., 2007). in spite of the importance of nickel in many industrial fields, but itis classified as heavy metal which leads to cancer due to concentration increasing in the soil and then in the food chain for human and animals, (2008،د. السعدي ). about one-third of the amount of nickel used in the industry comes from the recycling of industrial wastes, including the remnants of thermal power stations which contain a number of important elements such as nickel, vanadium, cobalt, cadmium, aluminum and others, the separation of these elements from the remnants of thermal power plants reduces areas used in landfill of these wastes and on the other hand these elements are of economic value(cunningham et al., 2007). several previous studies have investigated the removal of nickel from fly ash. sulfuric acid was used to separate nickel from residual solution after the separation of vanadium and molybdenum from fly ash. soluble nickel treatment with sodium carbonate was used to obtain nickel carbonate in the form of precipitation. the extracted nickel ratio was 85% by weight (stas et al.,2007). nitric acid was used to extract nickel from fly ash and the extraction ratio for nickel was 80% by weight. nitric acid was found to be more efficient than sulfuric acid when comparing the results of that study (mousa et al., 2011) with another results search (ashraf,2000). ammonium hydroxide was used as adsorption substance to extraction nickel from fly ash. the study shows that increasing of the mixing speed of the mixture and temperature increases the ratio of nickel separation. this study also showed that the dominate step of the reaction is the liquid layer surrounding the particles of fly ash (mousa et al.,2012). the electrostatic deposition method was used to extract the adsorbed nickel from fly ash after being treated with sulfuric acid. the extracted nickel was 75% from nickel weight in fly ash and purity was 97.83% (2007 ،أ.د عماد أيوب يوسف و اخرون ). mailto:bashhash66@gmail.com journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 198 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. nickel was separated from catalysts, which were found to contain 8.15% of dry weight. sulfuric acid was used in the separation process and was found better than nitric acid and hydrochloric acid when the ph of the solution was adjusted to 9.92 using sodium hydroxide. the separated nickel was 80% weight of nickel in catalysts (othman & yulisman,1999). the modified akita method was used to separate nickel by using ammonium hydroxide and deposition by sodium sulfate. the ratio of nickel to vanadium was 27% and then vanadium was separated using sodium carbonate and precipitated by ammonium chloride. the ratio of vanadium to nickel was 55% (al-ghouti et al.,2011).nickel was separated from fly ash by sodium carbonate and ammonium chloride. the nickel ratio in the solution was 91% after that nickel was deposed by sodium sulfate with 99.9% efficiency and purity of 99%(abu zaid,2010). fly ash was found to be a good adsorbed material for nickel in contaminated water, especially in low concentration after being treated with sodium hydroxide (visa & duta,2008). nickel and other heavy metals beyond chromium and cadmium converting them with silicon, calcium, aluminum and iron oxide to material of a glass nature that have little harmful effect on the environment and lesser size, which leads to reduce the area used for landfill fly ash (sobiecka & sroczynski,2011). the aim of this research is to study the possibility of separating nickel from fly ash using phosphoric acid and determining the best condition for nickel separation. practical work the fly ash was obtained from the south baghdad thermal power station, where it was classified into several sections of particles with different diameters ranging from (150-1000 micrometers) by the vibrator sieve apparatus. phosphoric acid (riedel-de haen company) was used as adsorption substance. a number of phosphoric acid solution with different concentration were prepared (2-10 molarities).a quantity of fly ash and phosphoric acid was placed in a glass flask with capacity of 0.5 liter and mixed by magnetic stirrer for different period of time ranging from (1 to 5 hours). after that, the solution was filtered with paper filter and yellowish green solution was obtained. the concentration of nickel and heavy metals in fly ash (shown in table 1) was determined by xepos atomic spectrometer device in the ministry of science and technologymaterial research center. the effect of particle diameter, duration time, concentration of phosphoric acid, temperature of solution and the ratio of acid to fly ash were studied. discussion of results the effect of phosphoric acid concentration on the separation of nickel from fly ash is shown in fig. (1). it was found that the separation of nickel ratio rises from 21% at 2 molarities to 50% at 5 molarities and noticed the increase of concentration of acid above 5 molarities had been accompanied by a small increase in the ratio of nickel separation. at 10 molarities of acid, the ratio of nickel separation equals 55% . the increase of the concentration of phosphoric acid is accompanied by an increase in the hydrogen ions in the solution, which increases the probability of exchange with the nickel oxide formed water and release the nickel in the solution. this result has been obtained in previous studies (stas et al., 2007),(othman & yulisman,1999) and (2007 figure (1) shows that the best concentration ناخرو .)أ.د عماد أيوب يوسف و of phosphoric acid is 5 molarities, with a nickel separation ratio equals 50%. to illustrate the effect of temperature on the separation of nickel from fly ash, a number of experiments were done with temperature ranging from (25 to 90)ºc. the results show increase separation ratio of nickel between (25 to 50)ºc is (50% ,58%) respectively. when the temperature exceeds 50ºc, the increase in the nickel separation ratio is very low. the increasing in temperature will increase the kinetic energy of hydrogen ions and increase the ability of hydrogen ions to remove the nickel from fly ash. it was found that the best degree of temperature to remove nickel is up to 50ºc where the nickel separation ratio is 58%. this result is shown in figure (2) and this result has been obtained in previous studies (stas et al., 2007) and (2007 ن.)أ.د عماد أيوب يوسف و اخرو the effect of duration time on the process of separating nickel from fly dust by phosphoric acid was illustrated by figure(3).it was observed that the separation ratio of nickel will increase from 39% to 78% when the time is increased from 1 to 4 hours. after this time the increase of the separation ratio of nickel is very low. this is because the increase of time gives the opportunity to release hydrogen ions from the phosphoric acid in the solution and react with the nickel compounds in the fly ash. after this time, the efficiency of adsorption is reduced because the hydrogen ions adsorption of most nickel oxide sites near the surface of the fly ash and only the deep sites remain in the pores contain the nickel oxide therefore the hydrogen ions need a longer time to reach the deep sites and these results were agreed with previous studies (stas et al.,2007),(mousa et al., 2011) and (2007 ،أ.د عماد و اخرون(. from the previous results it was shown that the best period for nickel separation from waste is (4) hours, which the separation of nickel ratio was 78%. journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 199 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. the ratio of phosphoric acid to fly ash was studies as shown in figure (4). it was found that the increasing of the ratio of acid to fly ash from (10-50) increases the separation ratio of nickel from (50%-89%) due to increase of hydrogen ions in the solution. the best ratio of acid to fly ash was found to be 30, where the nickel separation ratio is 81%. after that, the increase in the ratio of acid to fly ash accompanied by slight increase in the ratio of nickel separated. these results were agreed with studies of (stas et al.,2007) and (2007 ،أ.د عماد و اخرون(. the effect of fly ash particle size on nickel separation ratio is shown in figure (5). small particles were found to be better than large particles of fly ash in the nickel separation process .the results of nickel separation ratio is (13,31,50)% for particles with diameters (1000-500,500-150,<150)µm respectively. this is due to the fact, that small particles has large surface area, which will react with hydrogen ions released from phosphoric acid easily and increase the adsorption efficiency of nickel. conclusion the percentage of nickel in fly ash, which is a waste of south baghdad thermal power station was found 0.1779% of total weight. the experiment showed the increase of phosphoric acid, temperature of solution, separated time and phosphoric acid to fly ash quantity the nickel separated was increased and the nickel separated increase when the diameter of particles were decreased. the nickel separation efficiency is 81% at phosphoric acid concentration 5 molarities, solution temperature 50 ºc, duration time 4 hours, phosphoric acid to fly ash equal 30 and diameter of particles less than 150µm . refrences 1. abu zaid, a.h.m., (2010), '' selective recovery of vanadium and nickel from heavy oil fly ash'' isotpic & rad. res., 42(3), pp 659-668 2.alghouti, a., m., al-degs, y.,s., hani, k., ziedan m., (2011), '' extraction and separation of vanadium and nickel from fly ash produced in heavy fuel power plants "chemical engineering journal '' 173 pp 191-197 3. amer ashraf ,(2000) '' processing of egyptian boiler-ash for extraction of vanadium and nickel'' physicochemical problems of mineral processing, v34,pp 153-161 4. cunningham, p.w., cunningham,a.,m.,saigo,b.,w.,2007 , environmental science: a global concern, ninth edition, published by mcgraw-hill companies, pag. 306-307,401,485 5. mousa, k.,m., al-saady, f.,a., mahmood, e., m., (2011), '' nickel recovery from residue of heavy oil using nitric acid'', journal of petroleum research & studies, no.3,pp.87-94 6. mousa, k.,m., m.ali, sh., i., hadi, h., (2012),''extraction of nickel from fly ash of heavy oil using ammonium hydroxide '', alqadisiya journal for engineering sciences, vol.5,no.1,pp.3843 7. othman, h.b. mat. & yuliusman, (1999),'' selective nickel recovery from spent catalyst''. world engineering congress and exhibition(wec99);kuala lampur, july 19-22 8. sobiecka, e., & sroczynski, w.,(2011) " fly ash vitrification as the effective physico-chemical waste stabilization method'' biotechnology and food science 75 (2),35-38 journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 200 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 9. stas, j., dahdouh, a., al-chayah, o., (2007),'' recovery of vanadium, nickel and molybdenum from fly ash of heavy oil-fired electrical power station'', chemical engineering, 51/2,67-70,syria. 10. visa, m., & duta, a., (2008) " cadmium and nickel removal from waste water using modified fly ash: thermodynamic study'' scintific study& research vol. ix(1) pp 73-82 .11 430-424،429، علم البيئة،الطبعة العربية،دار اليازوري العلمية للنشر و التوزيع،صفحة 2008،حسين السعدي د. .12 ، استخالص النيكل من مخلفات حرق2007،أ.د عماد أيوب يوسف ، د. مؤيد كاصد جلهوم ، ليث يوسف يعقوب 321-343، صفحة 3،ملحق العدد52بائيا، مجلة الهندسة و التكنولوجيا،المجلد الوقود الثقيل باإلذابة المائية و ترسب فلزه كهر .13، كيمياء التربة،الطبعة المترجمة،دار الكتب العلمية للطباعة و النشر2012،أ.د. نور الدين شوقي علي ,أ.د. شفيق جالب سالم 4التوزيع،صفحة و table (1): concentration of some important elements in the fly dust from south baghdad thermal power station element vanadium chromium iron cobalt nickel molybdenum concentration(wt%) 0.6817 0.0260 10.01 0.003 0.1779 0.0272 0 10 20 30 40 50 60 70 80 90 100 0 2 4 6 8 10 12 a d so rp ti o n r a ti o % concentration of acid (molarities) fig.(1): effect acid concentration on nickel removal (granular diameter ≤ 150µm, acid to fly ash ratio=10,time=3hours,temperature =25 º c( journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 201 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 20 40 60 80 100 0 1 2 3 4 5 6 a d so rp ti o n r a ti o % time (hour) fig.(3); effecte of time on nickel removal ( granular ≤150µm, acidic=5, temperature=25ºc, acid to fly ash=10) 0 20 40 60 80 100 0 20 40 60 80 100 a d so rp ti o n r a ti o % temperature ( ºc( fig. (2): effect temperature on nickel removal (granular diameter ≤ 150 µm, acid to fly ash=10, acidic=5, time=3 hours) journal of al-qadisiyah for engineering science vol.11, no. 2 issn: 1998-4456 page 202 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 a d so rp ti o n r a ti o % acid to fly ash ratio fig (4): effect of acid to fly ash ratio on nickel removal (granular diameter≤150µm, acidic=5, time =3 hours, temperature=25ºc( 0 10 20 30 40 50 60 70 80 90 100 1 2 3 a d so rp ti o n r a ti o % granular diameter ( 1150 µm 2500µm 31000µm( fig. (5): effect of granular diameter on nickel removal ( acid to fly ash=10, time=3 hour, acidic=5 , temperature = 25ºc( article al-qadisiyah journal for engineering sciences 12 (2019) 240–245 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: muntadernajaf@gmail.com (muntadhar h. ismeala) https://doi.org/10.30772/qjes.v12i4.240 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. comparison the performance evaluation of xgpon-rof system with wdm and scm for different modulation schemes muntadhar h. ismeala a, bashar j. hamzaa a, wasan kadhim saada a a department of communication technical engineering, al-furat al-awsat technical university,alnajaf , iraq. a r t i c l e i n f o article history: received 01 november 2019 received in revised form 20 october 2019 accepted 31 october 2019 keywords: xgpon ber rof srm wdm scm a b s t r a c t at the present time and as a result to the recent developed technology demand for higher data rate and capacity has been increased. for the wireless networks, the combination of radio over fiber (rof) with (xgpon) gigabit-capable pon techniques produce a high data rate at lower cost. thus, this paper illustrates that the performance of rof-xgpon optical link has been analyzed for multi-channel through combining two multiplexing techniques, such as; subcarrier multiplexing (scm) and wavelength division multiplexing (wdm). the proposed system utilizes wdm-xgpon and scm-xgpon architecture combined with rof technology with 10 gpbs data rate and (2.4, 5.8, 10 and 15) ghz radio frequency (rf), when change the optical fiber length between (10 to 80) km. the network performance is compared with various digital quadrate amplitude modulation schemes, like ; 4 qam, 16 qam and 64 qam for various input power (-2, 2, and 6) db. the performance analysis is based on the optical spectrum of transmitted and received signals for 4-channel, constellation diagram, eye diagram, bit error rate (ber), power received, and quality factor. the result explain that the wdm-xgpon-rof performs better than scm-xgpon-rof for different modulation schemes. the bit error rate for wdm-xgpon less than the scm-xgpon while the power received recorded to the wdm-xgpon greater than scm-xgpon and the quality factor for scm-xgpon less than the wdm-xgpon. therefore the simulation results show that the wdm-xgpon-rof gives better performance from scm-xgpon-rof. the software optisystem version 15 has been used to simulate this system © 2019 university of al-qadisiyah. all rights reserved. 1. introduction rof is one of the most important applications in fiber optic system. in rof, light is set to a radio frequency and transmitted over fiber optics for easy wireless access . technically, rof is a hybrid system that combines wireless and optical in one system leading to high capacity, high data rate, transparent and mobile solutions [1]. rof networks allow customers to retain their traffic while also providing them with the necessary bandwidth http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 241 muntadhar h. ismeala et al. /al-qadisiyah journal for engineering sciences 12 (2019) 240–245 for current and future connections [2]. passive optical network (pon) a network with multiple optical fibers and a variety of broadband services [3]. pon remove all active components between the client and the server. this is done by introducing passive optical components to route traffic over the network. the passive optical network acts as a transmission device between olt and various ont through optical subdivisions, which removes multiplex or multiplex signals by destination and origin. therefore, the network has three devices: olt, ont and splitter, and each has its own function on the passive optical network which is necessary. xgpon is a variant of pon technology which can support higher data rate (10 gbps) using a point to multipoint access mechanism. a xgpon system is a point-to-multipoint network architecture deploying optical access lines between a carrier’s central office and customer sites [4]. the major advantage of using xgpon standard that is its more speed as compared too other pon standards. it is observed that xgpon bandwidth 10 gbits/s for individually subscriber. the rof system is integrating wireless and fiber based technology. the main objective of the rof system is to distribute broadband signals to distributed base stations for wireless access using an optical access network[12]. the pon combination with rof technology provides a high capacity solution and high data rate[10]. waveform division multiplexing (wdm) the basic concept of wdm technology is to combine multi-channel optical with different wavelengths that come from different optical sources to a single fiber through multiple transmitters used on the sender side as well as multiplexer removal tools on the side of the receiver to split wdm channels[11]. however, wdm is an effective method that can be used in the fiber optic feeder network to increase the capacity of rof systems, increase the usable fiber bandwidth and increase the number of base stations supported by the central office [5,6]. subcarrier multiplexing (scm) technology is one of the multicast technologies that can be used in the optical system to increase bandwidth efficiency. scm is more sensitive to noise effects, limiting data rates and maximum sub-carrier frequencies[8,9]. optical sub-carrier multiplexing (osm) is a system in which more than one signal is transmitted in the radio frequency field and then transmitted through the use of a single wavelength[7]. in this paper, we analyze and compare between rof-xgpon-wdm and rof-xgponscm system regarding parameters such as transmission distance, eye diagram, power, q factor and ber. it shows the rof-xgpon-wdm is more energy efficient and transmits data at long distance with low losses and best ber as compared to the rof –xgpon-scm. the systems performance is analyzed on the basis of variation of factors such as quality factor , eye diagram and minimum ber using 15 optisystem. 2. system design the main goal of this paper is to investigate the intergration of rof with xgpon. the system design as shown in fig. 1. includes four main parts which are transmitter, fiber channel, splitter and receiver. used as a source of data with 10 gbps of data rate the pseudo-random bit sequence generator (prbs). the qam sequence generator utilized as qam modulator for the data rate. band-pass filter (bpf) utilized at both transmitter and receiver to get the detecated spectrum. the mach-zehnder modulator (mzm) used as optical modulator which modulate the radio signal over light signal that generated by continuous wave laser (with 1500 nm of wavelength). the splitter 1x32 device splits evenly the signal input power to 32 output ports. at the receiver side, after photodetection by positive-intrinsic-negative (pin), filter the signal and amplify it to regenerate the required signal. the signal then fed into bit error rate (ber) analyzer and the spectrum for data analysis. figure 1. rof-xgpon system design however, 4-rf channels (2.4 ghz, 5.8 ghz, 10 ghz and 15 ghz) are simulated through used (4-qam,16-qam and 64-qam) modulation techniques. the proposed simulation setup model for the scm-xgponrof system is shown in fig. 2. transmitter part receiver part figure 2. simulation setup model for the scm-xgpon-rof system channels with different wavelengths coming from different optical sources into a single fiber using multiplexers at the transmitter end and demultiplexers in the receiver to split wdm channels, which are simulates through use different modulation techniques. the proposed simulation setup for the wdm – xgpon-rof model shown in fig. 3. 242 muntadhar h. ismeala et al. /al-qadisiyah journal for engineering sciences 12 (2019) 240–245 transmitter part for wdm-xgpon receiver part for wdm-xgpon figure 3. simulation setup model for the wdm-xgpon-rof system 3. result and discussion the performance of the proposed system depended on many factor like eye diagram, ber, quality factor, power and constellation diagram. to compare the performance of scm-xgpon-rof system with wdmxgpon-rof. the relation between max. q factor and ber. figs. 4 and 5 shows received constellation diagram for the scmxgpon and wdm-xgpon, respectively, after 50 km. the distortion in the signal at the receiver is increased in scm-xgpon system greater than wdm-xgpon. c.64-qam scm-xgpon b.16-qam scm-xgpon a.4-qam scm-xgpon figure (4) constellation diagram for the scm-xgponrof system model for different modulation scheme c.64-qam wdm-xgpon b.16-qam wdm-xgpon a.4-qam wdm-xgpon figure (5) constellation diagram for the wdm-xgponrof system model for different modulation scheme 243 muntadhar h. ismeala et al. /al-qadisiyah journal for engineering sciences 12 (2019) 240–245 figs. 6 and 7 shows the eye diagram for the scm-xgpon and wdmxgpon after 50km. the shown the signal quality high speed digital transmission. the eye diagram for wdm-xgpon clear and open is better than scm-xgpon. figs. 8 and 9. shows the opposite of ber with the length of optical fiber length. the distance from 10 km to 80 km. the ber increase when the fiber length is increase. the system wdm-xgpon obtained a good results because the ber less than scm-xgpon. the 64-qam for wdm at 49 km the bit error rate less than 10-9 [10] acceptable level while the ber for 64-qam for scm less than 10-9 at 46 km. this variation of power received with fiber has been for three types of modulation 4-qam, 16-qam and 64-qam shows in figs. 10 and 11 for scm-xgpon and wdm-xgpon respectively. the power received recorded in wdm-xgpon system high power than scm-xgpon system. the 64-qam modulation for scm at 50 km record – 21.33dbm while the power received for wdm at 50 km is – 19.73dbm. the ber versus the length fiber when the input power is different ( 2dbm, 2dbm and 6 dbm) for scm-xgpon and wdm-xgpon system shows in figs. 12 and 13 respectively. from the results, the ber increasing when the fiber distance been longer (from 10 km to 80 km). results for ber of wdm best of scm when input power is different (2dbm, 2dbm and 6 dbm). the 64-qam modulation for scm at 50 km when input power is 6 dbm the ber is 3.50×10-15 while for wdm at 50 km is 6.50 ×10-17. c.64-qam wdm-xgpon b.16-qam wdm-xgpon a.4-qam wdm-xgpon figure (7) eye diagram for the wdm-xgpon-rof system model for different modulation scheme c.64-qam scm-xgpon b.16-qam scm-xgpon a.4-qam scm-xgpon figure (6) eye diagram for the scm-xgpon-rof system model for different modulation scheme figure (8) ber versus length of fiber for scm-xgpon figure (9) ber versus length of fiber for wdm-xgpon 244 muntadhar h. ismeala et al. /al-qadisiyah journal for engineering sciences 12 (2019) 240–245 figure 10. power received versus length of fiber for scm-xgpon figure 11. power received versus length of fiber for wdm-xgpon figure 12. ber versus length of fiber for scm-xgpon figure 13. ber versus length of fiber for wdm-xgpon the quality factor for scm-xgpon system and wdm-xgpon system shows in figs. 14 and 15 respectively when the input power different (-2dbm, 2dbm and 6dbm). when increase the fiber the quality factor decrease. the quality factor for wdm greater than scm. the 64qam modulation for scm at 50 km when input power is 6 dbm the q factor is 6.90 while for wdm is 8.10 figure 14. quality factor versus length of fiber for scm-xgpon figure 15. quality factor versus length of fiber for wdm-xgpon 4. conclusion the xgpon combining it with the rof system, which produces a system with very high efficient communication that uses the bandwidth effectively. thus, the xgpon-rof system possess better efficiency compared with the existing communication standards. in other words, combining between the xgpon and rof will provides a robust communication by using the advantages of the optical fiber. in this paper, (wdm-xgpon) and (scm-xgpon) were compared with (rof) for constellation diagram, eye diagram, ber, power received, and q-factor at different fiber length and at multi input power levels and use three modulation schemes, such as; 4 qam, 16 qam and 64 qam. the eye diagram for wdm-xgpon open and clear is better than scm-xgpon while power received for wdm-xgpon at 50km is -19.73 dbm when power received for scm-xgpon -21.33 dbm at the same distancethe results for ber when input power 6 dbm and modulation is 64-qam at 50km the wdm-xgpon 6.50 ×10-17 and the scm-xgpon 3.50 ×1015.the simulation results show that the system wdm-xgpon gives the best results from scm-xgpon. in addition, with the increased of data with decrease the quality. furthermore, increase in constellation points are illustrated in the constellation output as well. 245 muntadhar h. ismeala et al. /al-qadisiyah journal for engineering sciences 12 (2019) 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[13] h. a. leftah and h. l. swadi " performa-nce evaluation of single carrier frequency [14] domain equilizer (sc-fde) over impulsive noise channel" vol .11, no .2, pp.273-277, 2018. article al-qadisiyah journal for engineering sciences 13 (2020) 262–267 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: zahraanzzal1992@gmail.com ( zahraa n.hussain) https://doi.org/10.30772/qjes.v13i4.697 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. green diesel production using egg shell derived cao catalyst: effect of catalyst and reaction process zahraa n. hussaina* , ali a. jaziea a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 4 september 2020 received in revised form 3 october 2020 accepted 19 october 2020 keywords: bio fuel cladophora glomerata deoxygenation calcium oxide a b s t r a c t increasing demand for fossil fuels and the resulting emissions for it have become an interesting research topic for biofuel production from renewable natural resources aimed at development and reduce greenhouse gas emissions. in this research, algae was used as a biological source for the production of biofuels because it has many advantages, represented by its high oil content, which may reach 50% of the dry cell weight, it does not need arable land, it can grow even in salt water. a cladophora glomerata alga was used and extraction oil from biomass with the help of methanol solvent was using a soxhlet device. the produced oil was being tested by fourier transform-infrared spectroscopy (ftir) as well as by thermal analysis and gas chromatography mass spectrometry (gc-ms). after that the resulting oil was used through the process of deoxygenation using a high pressure reactor with a heterogeneous catalyst prepared from natural sources. recent studies have shown that these catalysts have high performance compared to other catalysts as well as low cost, because they can be obtained from natural sources that are abundantly available. heterogeneous catalysts were produced in this paper from chicken eggshells by calcining them at high temperatures to obtain calcium oxide (cao) and these catalysts were characterized using x-ray diffraction (xrd), fourier analysis of infrared spectrum (ftir) and brunauer emmet surface area. -teller (bet). ultimately, fuel properties similar to those of mineral diesel are obtained. represented by flash point 49, cetane number 39, cloud point 7, calorific value 41 and acid value 0.374. © 2020 university of al-qadisiyah. all rights reserved. 1.introduction the transport sector currently accounts for approximately 19 per cent of global energy demand gadonneix et al. [1]. the worldwide demand for petroleum is projected to rise to 18 million 𝒎𝟑per day by 2040 briefing et al. [2]. energy lack refers to a crisis of energy resource to an economy. there has a large uplift in the universal demand for energy in the recent years as a result development of manufacture and growth of population. the request for energy, especially from liquid fuel, and limitations on the rate of fuel product have created such a phase ago the early 2000s, lead to the current energy crisis. the rise may be overconsumption, aging infrastructure, disturbance or crises in oil refineries and harbor facilities that restrict fuel supplies durakovic et al. [3]. the limited fossil fuel reserves global warming increase due to high carbon dioxide emissions has led to a global spread quest for reliable and renewable energy sources for the transport strip knothe et al. [4]. this can only be investigated by developing a new technologies or by updating existing technologies aviation et al. [5]. there are different renewable sources of energy widely found on earth, including biomass, solar , wind and nuclear sources, which can replace fossil fuels [6],[7],[8]. however, during its treatment, these renewable energy sources eventually caused many issues related to waste management and radioactive emissions from biomass and nuclear energy [9],[10],[11]. biomass energy has therefore been known as the most promising source of renewables in the transport sector zulkepli et al. [12]. biomass is a renewable resource and carbon neutral in principle wang et al. [13]. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ zahraa n. hussain , ali a. jazie /al-qadisiyah journal for engineering sciences 13 (2020) 262–267 263 biomass and biofuels derived from biomass like as biogas, green diesel, bio methane, bioethanol, biodiesel , green gasoline and bio hydrogen are of global interest, since they can mitigate atmospheric 𝐶𝑂2 levels and replace fossil fuels in future energy outfit douvartzides et al. [14]. biofuel has many characteristic exceeds fossil fuels including biodegradability, nontoxicity, sustainability and decrease emissions of 𝐶𝑂2 exceptionally sajjadi et al. [15]. biofuel is produced from biomass material like oils of vegetable such as rapeseed, palm, corn, sunflower, soybean, coconut, camelina, peanut, carinata, cottonseed and jatropha oils), animal fats, algal oils and waste cooking oils used anuar et al. [16]. foodstuff based biofuels can impact the availability and the price of food, particularly in developing country braun et al. [17]. lately, algae as a biomass feedstock have been selected to avert the confrontation of food vs. fuel and changes of use earth [18],[19]. algae have large potential as feedstock's for bioenergy output due to their rise product, rapid growth rate, ability to rectify 𝐶𝑂2 and for non-competition with a food crops. the raw algae could be pyrolysed to obtain a liquid bio oil that still retains a significant fraction of initial energy of the algae fermoso et al. [20]. biofuels based on algae are considered a viable option, because they do not affect the supply of food. they can also be cultivated on any available ground, water or saline shen et al. [21]. some drawbacks of bio-oil based on algae, like low heating value, corrosiveness, instability of thermal, rise of viscosity, and have impeded its use in practice because of height oxygen amount, up to (35–40%). therefore, deoxygenation is the secret to upgrade of algae based bio oil nguyen et al. [22]. the amount of oxygen in a plant oil can be eliminated by deoxygenation (do), which undergo process of decarboxylation ( 𝐶𝑂2 ) and decarbonylation ( 𝐶𝑂 ) [23],[24],[25]. catalytic deoxygenation (do) was produced to efficiently product biofuel based on a green hydrocarbon in the non-presence of 𝐻2 by eliminate compounds of oxygen from the plant oil in the shape of 𝐶𝑂 , 𝐶𝑂2 and 𝐻2𝑂 by using solid acids or base catalysts [23],[26],[27]. therefore, metal catalysts have been synthesized for deoxygenation process has continuously searched because of desired properties like higher catalytic activity, high rotation frequency, high chemical stability and little amount of catalysts wanted for catalysis. this catalytic property would lead to a high yield of desirable deoxygenated product in a short reaction time as contrast with a non-catalysed deoxygenated process. the metallic catalyst could occur in the form of pure metals, mix metallic (trimetallic, metallic alloy, or bimetallic), metallic oxides, metallic nitrides, metal phosphates or metallic carbides [28],[29]. heterogeneous metal catalysts are usually used as solids for deoxygenation when the product compounds are in liquid or gas phase tanaka et al. [30]. the addition of acid sites in catalysts improves the cracking and abscission of (𝐶 − 𝑂) and (𝐶 − 𝐶 ) bonds linked in the biomass structure by dehydration, decarboxylation, aromatization, isomerization, cracking, dealkylation and oligomerization shen et al. [31]. calcium oxide was used as a catalyst made from organic calcium compounds (org-cao) yi et al. [32]. several studies have indicated that 𝐶𝑎𝑂 catalysts derived from organic calcium precursors have outstanding unique surface areas and rich porous structures that provide more active 𝐶𝑂2 capture sites than traditional 𝐶𝑎𝑂(𝑂𝐻)2[33],[34]. lowcost 𝐶𝑎𝑂 is a perfect catalyst for deoxygenation asikin-mijan et al. [35]. organic calcium precursors tend to produce 𝐶𝑎𝑂 with better reactivity and recyclability [34],[36]. in the present work it has been suggested that calcium oxide could be prepared from the chicken eggshell as an efficient catalyst for deoxygenation. processing cao catalyst activity was tested by using x-ray diffraction (xrd) fourier analysis of infrared spectrum (ftir) and brunauer emmet-teller (bet) surface area characterization. algal oil and the product biofuel were characterized using (gc ms) and (ftir) methods. cladophora glomerata algae were investigated as a raw material for the deoxygenation process due to the high oil content. the properties biofuel also was investigated. 2.material and method methanol: ( 𝐶𝐻3𝑂𝐻 ), (m.wt=32.04) and purity (99.8%), (fisher scientific, india). algae (cladophora glomerata). nitrogen gas: nitrogen (supplied from al-diwaniyah north factory, iraq) of purity greater than 95% was used as inert gas medium during the process, (m.wt = 14.0067). eggshells: chicken egg shells were collected from local restaurants in diwaniyah, iraq. 2.1. catalyst preparation heterogeneous catalysts of eggshells were prepared, as a quantity of chicken eggshells were collected, then thoroughly cleaned and rinsed with water to get rid of the organic matter contained in them. the crusts were dried under the sun rays for 24 hours, after which the crusts were ground into a fine powder before the calcification process, and the calcification process was performed in the combustion oven using different temperatures and at different times. several experiments were performed for the calcification process with temperatures between (850˚c to 950 ˚c) and time ranging from (2 3) hour. 2.2. characterization characterization of heterogeneous catalyst has been discussed using xray diffraction (xrd), infrared spectroscopy (ftir), and bruner emmett-tiller (bet). the (xrd) spectra of a copper shell calcined egg samples (𝜆 = 0.154178 𝑛𝑚) were obtained at (40 𝑘𝑉) and (30 𝑚𝐴), the scanning velocity 0.1 ˚ / s, and the range of scan from (10 80 °c). upon calcification, the egg shells are completely white, which confirms that the product has eliminated calcium carbonate, which is only calcium oxide engin et al. [37]. the fourier transform infrared (ftir) mechanism is using for identify organic materials. this mechanism measures the extent to which a sample absorbs infrared radiation to its wavelength. the infrared absorption bands define the molecular structures of the sample and components. the test applied at al-qadisiyah university at the college of engineering by using ftir using bruker, tensor ii, germany and the resolution of this device used within the spectrum range 4000-400 cm-1. the bet (brunauer-emmet-teller) surface area, pore volume and average pore diameter of the catalysts were determined via nitrogen physisorption at 77 k using a micrometrics, asap 2020 bet surface area analyser in university of tehran. 2.3. experimental catalytic deoxygenation and cracking reactions in a high reactor of pressure were carried by using algae oil cladophora glomerata at nomenclature do deoxygenation bet brunauer emmett teller xrd x-ray diffraction ftir fourier transform-infrared spectroscopy 264 zahraa n. hussain , ali a. jazie/al-qadisiyah journal for engineering sciences 13 (2020) 262–267 temperature ranged between (260 – 360 ˚𝐂) at time range between (2 4) hours, at pressure of the nitrogen used between (5 10) bar with a mixing cycles ranged between (600 1400) rpm. calcium oxide catalyst has been used, the ratio of catalyst to oil ratio range between (5 10) g. from view of a chemical point, removing oxygen at high temperatures and the relative pressure of nitrogen is a complex operation that involves a series of cascading reactions. fatty acids are converted to biofuels by a catalytic deoxygenation reaction by breaking a bond (𝐶 − 𝐶) using nitrogen gas. the bonds (𝐶 = 𝐶) are first hydrogenated, and then oxygenated from the front to produce alkanes. free fatty acids are converted to saturated hydrocarbons, including n-pentadecanes ( 𝐶15𝐻32 ) and n-heptadecanes ( 𝐶17𝐻36 ) and to nheptadecenes unsaturated (monounsaturated and unsaturated). the oxygen is removed in the form of carbon dioxide, throughout the reaction of the carbonation the free fatty acids are converted to the unsaturated npentadecanes and nheptadecenes including mono-unsaturated (𝐶15𝐻30 ,𝐶17𝐻34 ), diunsaturate (𝐶17𝐻32 ) and poly-unsaturated (𝐶17𝐻28 ). the produced hydrocarbons may be exposed to further cracking reactions to produce hydrocarbons with shorter chains by breaking the bond (𝐶 − 𝑂). 3.results and discussion 3.1. basic properties of the prepared catalysts fig. 1 shows the x-ray diffraction peaks of the catalyst samples cao850 and cao-900 indicated the presence of a pure cao crystalline phase. the concentration of the typical peaks of cao phase is higher when high activation temperatures are used. these changes in density and peak width might indicate somewhat greater dimensions of cao crystals formed at high activation temperatures. based on the known crystalline phases (pure cao) and crystalations sizes in cao-catalyst specimens calcined at high temperatures, starting from 850 ° c, we can deduce that there is a exigency to activate the cao catalyst with heat treatment prior to use. this remark is consistent with those of others author boey et al. [38].. the calcination at 900 ° c cause the remove carbon dioxide co2 from the calcium carbonate 𝐶𝑎𝐶𝑂3 in the natural waste crust and creates calcium oxide cao. the narrow and high intensity peaks of the calcified catalyst define the fully crystallized structure of cao. the waste shell catalysts showed obvious and sharp peaks corresponding to the crystal phase of calcium oxide cao. the peaks of calcined eggshell at 900𝐶 ° show 2𝜃 values of 33, 37, and 54 which are the characteristic peaks for cao results were shown similar to those written by buasri et al. [39]. fig. 2 has proven that high calcification temperatures cause an increase in activity cao. the calcification result was annotated by drying 𝐶𝑎(𝑂𝐻)2 and converting 𝐶𝑎𝐶𝑂3 to 𝐶𝑎𝑂 in addition to increasing the amount of active sites, where it occurred in a non-preserved absorption catalyst at the main absorption ranges at 1415, 879, and 700 cm-1 , which was caused by asymmetric expansion. . outside the vibration modes are the flat curve and the curvature inside the plane, respectively. the functional group (𝐶𝑂3 −2 ) upon calcification, egg shells begin to lose carbonate ranges and absorb molecules ( 𝐶𝑂3 −2 ) to a highest energy (which, 1470, 1040, 𝑎𝑛𝑑 820 𝑐𝑚−1) jazie et al. [40]. this is due to the reduced mass of the ionsrelated functional group (𝐶𝑂3 −2 ). sharp expansion (𝑂𝐻−1) is observed at 3689 cm1 at the calcined catalyst at 900 ° c consistent with that observed [37]. table 1 surface area of the bet for a catalysts manufactured from eggshell at temperature (900˚𝐶) was high attain ( 58.155 𝑚2𝑔−1 ). research shows bet that a particle volume decreases with increasing temperature of calcination from ( 850˚𝐶 − 900˚𝐶 ) lead to a raise the surface area. another increase in the temperature to 950 ˚c the particle volume increases and surface area decreases due to sintering and collapse of pore structure jazie et al. [41]. catalysts calcined at degree of 850 ° c and 950°c have a low surface area. eggshell catalysts calcined at degree of (850°c and 950°c) are consider materials that less porous because of the size of a trace pores, whereas the calcined of a catalyst at (900 ° c) temperature shows the best structure of porous. therefore, these results indicate that a decomposition of a carbonate takes place at a temperature (900 ° c). figure 1. xrd of catalyst for egg shell calcined at (𝟖𝟓𝟎˚𝑪, 𝟗𝟎𝟎˚𝑪 𝒂𝒏𝒅 𝟗𝟓𝟎˚𝑪) on respectively figure 2. ftir spectra of calcined egg shell at (𝟖𝟓𝟎 ˚𝑪, 𝟗𝟎𝟎 ˚𝑪 𝒂𝒏𝒅 𝟗𝟓𝟎 ˚𝑪) respectively at 𝟑𝒉 table 1brunauer emmett teller (bet) surface area and total pore size of the egg shell specimen calcined at (𝟖𝟓𝟎˚𝑪, 𝟗𝟎𝟎˚𝑪 and 𝟗𝟓𝟎˚𝑪) on respectively raw material calc.temp. (oc) a surface of area (𝑚²/𝑔) a total pore of size (𝑐𝑚³/𝑔) egg shell 850 3.4056 0.15455 egg shell 900 5.8155 0.109827 egg shell 950 4.8864 0.018494 900˚𝐶 950˚𝐶 850˚𝐶 zahraa n. hussain , ali a. jazie /al-qadisiyah journal for engineering sciences 13 (2020) 262–267 265 3.2. reaction results the composition of the organic liquid products was characterized via fourier transform infrared spectroscopy (ftir) and gas chromatography-mass spectrometry (gc–ms). according to meng et al. [42] fig. 3 a distinctive absorption bands in an infrared spectrum of a macromolecules were: a) lipids bands in a range of (3000 – 2800 𝑐𝑚 −1 ). in this study, a lipid amounts was soft. b) carbohydrates bands among (1200 𝑎𝑛𝑑 950 𝑐𝑚 −1) and c) two type of amide bands of proteins i and ii, located at (1734 – 1584 𝑐𝑚 −1) and (1584– 1495 𝑐𝑚 −1) respectively. moreover, it also been advertise those (𝑁 − 𝐻) protein binding vibrations may happen in (1555 𝑐𝑚 −1) , d) a (𝐶 − 𝑂 − 𝐶) polysaccharide bands happen at range (1050– 1098 𝑐𝑚 −1)xu et al.[43]. finally, the range (2255– 2407 𝑐𝑚 −1) represents the presence of carbon dioxide at an environment [44],[45]. to determine the oxygen removal efficiency, the peak intensity reductions were comparable with the reduced oxygen content in the product by comparison with the non-oxygenated liquid product. the absence of a bond (𝐶 − 𝑂 − 𝐶) at (1014.91 𝑐𝑚−1) indicates that a triple bond such as an ester has been eliminated aliana-nasharuddin et al. [46]. liquid product formulations were evaluated with by using gas chromatograph mass spectrometer (gc-ms) (agilent 6890n series gc with a 5973 n inert ms detector and 7683 injector). gc ms analyzes were performed in order to find out the hydrocarbons present in algae oil and the fuel produced from algae oil after deoxygenation. different classes of hydrocarbons were obtained which include aromatic amines, nitriles, alkenes and carbohydrates. the most saturated fatty acids (sfas) in c. glomerata myristic acid and palmitic acid. light hydrocarbons from (c9-c10) represent the highest yields in the resulting biofuels. also noted is the large existence of a hydrocarbon with chains containing one less carbon than the chains of carbon in oil of algal. those odd numbered carbon compounds are generated by decarbonylation or decarboxylation reactions. a presence of a molecules containing an even number carbon (𝐶12, 𝐶14, 𝐶16) could be related to reactions of dehydration [47],[48],[49]. figure 3. ftir of biofuel production by deoxygenation for c. glomerata algae 3.3. assessment of the basic fuel properties the properties of the resulting biofuels are shown in table 2. the algal oil has relatively close fuel properties to those of metallic diesel. in comparison with a specific gravity of a petroleum diesel of 0.85, the specific gravity of the biofuels resulting from the current degradation was (0.84) for cladophora glomerata algal oil. the astm d445 standard specified an acceptable range of biofuel viscosity at 40 ° c. the main flow characteristics of the biofuel specifications are the intake and pour point. the intake and pour points are found at (-1) ° c and (-5) ° c for algae oil esters cladophora glomerata according to (astm d92-53) standard. the acidic value of biofuels produced from algal oil was (0.374 mg koh/g and) for cladophora glomerata good within the limits of the biofuel standard (astm d664) (0.8 mg koh/g). to calculate the cetane number for biofuel according to (astm d 976) in this current decomposition the number of cetane for esters of algae oil for cladophora glomerata was (39), while the typical value for diesel was (40). as a result, most of the characteristics of the biofuel resulting in this current work can be compared with the characteristics of standards astm for green diesel. table 2 fuel properties of biofuels produced with testing methods properties cladophora glomerata green diesel astm d 6751 green diesel method of test kinematic viscosity at 40 ˚c 3.2 1.9 – 1.3 astm d445 specific gravity (kg/m3 or gm./ml) 0.84 0.82 0.85 astm d4052 flash point (˚c) 49 52 – 28 ˚c astm d92-53 cetane number 39 40 min. astm d976 cloud point (˚c) 7 – ip15/60 pour point (˚c) -6 -35 – 14 ip15/60 acid value (mg/koh/g) 0.374 0.6 max. astm d 664 calorific value (mj/kg) 41 – ip12/63t 4.conclusions the use of waste is an important element in sustainable development, and waste is seldom used to be used in the production of practical products. most waste shells contain quantities of (caco3) which can be converted into (cao) by exposing them to high temperatures in the calcification process and as a result it can be used as cheap catalysts for biofuel production. the deoxygenation process with catalysts calcium oxide showed the possibility of producing alkanes without the need for hydrogen gas. the results showed a higher selectivity towards products with a range (c8 c12) compared to products with a higher range (c13 c16). the deoxygenation pathway under pressure of nitrogen by decarboxylation is proposed as the main pathway and decarbonylation as the secondary pathway. as for the characteristics of the produced biofuel, the number of cetane, heating values and the specific gravity are identical to those of mineral diesel. references [1] p. gadonneix, a. sambo, l. tie’nan, a.r. choudhury, j. 266 zahraa n. hussain , ali a. jazie/al-qadisiyah journal for engineering sciences 13 (2020) 262–267 teyssen, j.a.v. lleras, a.a. naqi, k. meyers, h.c. shin, m.-j. nadeau, global transport scenarios 2050, transp. london world energy counc. 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[49] t. v choudhary, c.b. phillips, renewable fuels via catalytic hydrodeoxygenation, appl. catal. a gen. 397 (2011) 1–12. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 468 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. studying the performance of a hydrotreating process for a mixture of gas oil and lighter fractions mohammad f. abid, department of chemical engineering, university of technology, baghdad, iraq. e-mail: 80005@uotechnology.edu.iq waleed h. abohameed, department of chemical engineering, university of technology, baghdad, iraq. e-mail: wa.code1991@gmail.com shakir m. ahmed, scop, ministry of oil, baghdad, iraq. e-mail: shakir58scop@gmail.com salah m. ali, petroleum research and development center, ministry of oil, baghdad, iraq. e-mail: salah56ali@yahoo.com saad kareem ibrahim, petroleum research and development center, ministry of oil, baghdad, iraq. e-mail: refoil.2005@gmail.com received on 29 august 2017 accepted on 31 october 2017 published on 15 january 2018 doi: 10.30772/qjes.v10i4.494 abstract: in the present study the applicability of hydrodesulfurization of a mixture of crude oil fractions (e.g., naphtha, kerosene, and gas oil ) in a single hydrotreating reactor packed with nicomo/al2o3 under various operating parameters such as temperature (310-370 oc), pressure (40-55 bars), weight hour space velocity (1.2 to 3.6 h-1), and hydrogen-toliquid hydrocarbon ratio (150-300 vol/vol). experimental results showed that temperature and pressure have a positive effect on process performance while weight hour space velocity gives a different trend. the optimum value of (h2/hydrocarbon) ratio was found experimentally to be 200 vol/vol after which the increase in this ratio cause mailto:80005@uotechnology.edu.iq mailto:shakir58scop@gmail.com mailto:salah56ali@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 469 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. reduction in hds% because decrease in contact between h2 gas and hydrocarbon in reactor. results showed that the best conditions (350 oc, 50 bars, 1.2 h-1, and 200 vol/vol) in which gave the hydrotreating (hds) efficiency of 95.8%.the results confirmed the applicability of the nicomo/al2o3 catalyst for hds reaction of a mixture of middle distillate (e.g., naphtha, kerosene, and gas oil). it was found that at higher pressure and temperature (i.e., t> 350 oc; p> 50 bars) a thermodynamic equilibrium was established. as observed, there is a 1.6% reduction in gas oil less than that of the conventional method. however, kerosene, heavy naphtha, and light naphtha undergo increases of 0.6%, 0.75%, and 2.75% respectively over these from conventional method. these results reveal that the quantity of fractions is almost the same for both methods. as it can be observed, that measured properties of the oil fractions produced by the proposed method are almost the same as those produced by conventional method. however, specific gravity (sp.gr) of the oil cuts produced by present study (i.e. sp.gr of kerosene, heavy naphtha, and light naphtha 0.785, 0.728, 0.655 respectively) is somewhat less than sp.gr of the same fractions produced by conventional methods (i.e. sp.gr of kerosene, heavy naphtha, and light naphtha 0.788, 0.738, 0.65 respectively), which gives a clear indication of properties improvement of these fractions. experimental results confirmed the applicability of the proposed method for hds of a mixture of iraqi middle distillates (i.e., naphtha, kerosene, and gas oil) simultaneously in a single fixed bed reactor. keywords: hydrotreating, mixture of crude oil fractions, nicomo/al2o3 catayst nomenclature api american petroleum institute ep end point of boiling point, o c gol gas oil and light fraction hds hydrodesulfurization hdt hydrotreating hn heavy naphtha htr hydrotreating reactor ibp initial boiling point, o c mhc mild hydrocracking ln light naphtha lpg liquefied petroleum gas lgo light gas oil p pressure, bar pr&d petroleum research & development rcr reduced crude oil sf weight content of sulfur in feed al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 470 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. sp weight content of sulfur in product sp.gr specific gravity of oil t temperature, o c whsv weight hour space velocity, h -1 introduction in a modern petroleum refinery, the hdt process includes a complex and sophisticated system due to a large number of reactors, vessels, controlling system with different operating variables (temperatures, pressure, lhsv and h2 to oil ratio) for each reactor. many technical problems have evolved from this sophisticated system. furthermore, high fixed capital cost is usually invested in this complex system. simplification of such system is one of the main goals of all engineers of the field. published data on hdt of a mixture of middle distillates in one time in a single hdt reactor are scarce. crude oil is complex mixture of various hydrocarbon compounds with different heteroatoms such as s, n2, o2 and some metals (ni and v). marketplace requests for different crude oil products are high. the typical consumption of different fuels (i.e. gasoline, kerosene, jet fuels, etc.) is equal to 40-50% of crude oil consumption and the worldwide consumption will rise in the next years so, it is necessary to growth distillate production at high quality. to meet these challenges, a lot of efforts have been committed and a number of oil upgrading machineries have been developed by leading petroleum research institutions. catalytic hydroprocessing seems to be a promising technology for upgrading of heavy oils (speight,2010). (heinrich and kasztelan 2001) analyzed various fractions, of a crude oil originally having a 1.2 wt.% sulfur, for sulfur content. they indicated that sulfur compounds tend to concentrate in the heavier fractions of oil, as shown in table (1). table (1): distribution of sulphur compounds in the various fractions of a crude oil originally having a 1.2% content in weight of sulphur (heinrich and kasztelan, 2001). fraction distillation sulphur sulphur compounds (wt.%) interval ( o c) wt. (%) mercaptans sulphides thiophenes benzo thiophenes and heavy sulphides gasoline 70-180 0.02 50 50 traces - kerosene 160-240 0.2 25 25 35 15 gas oil 230-350 0.9 15 15 35 35 vacuum gas oil 350-550 1.8 5 5 30 55 residue >550 2.9 traces traces 10 90 the influence of sulfur content on the performance of como/al2o3 hydrotreating catalyst was inspected by (rana et al., 2004) using different model reactants in a batch reactor at 4 mpa and 340 o c. the effect of sulfur (0–2 wt.%) content was studied by varying the loadings of dbt. authors indicated opposite effects of the produced h2s on selectivity. a slurry batch reactor was utilized by (deng et al. 2010) to study hds of diesel fuel at different operating conditions (pressure = 3-5 mpa, temperature = 320360 o c, and hydrogen flow rate up to 2.8 l * min -1 ). the catalyst used was nimo/al2o3 with loading 4-23 wt.%. the authors concluded that the reaction rate increased as temperature, pressure, and flow of hydrogen. the catalyst loading was found to have a positive effect on reaction rate. (farag ,2012) investigated the catalytic performances of unsupported catalysts of the hydrodesulfurization process for sulfur removal from gas oil and compared the result with the result that obtain from a supported catalyst. the hydrodesulfurization reactions were carried out in a batch reactor when the temperature and pressure equal to 340 °c and 3 mpa, respectively. authors reported that the http://europepmc.org/search;jsessionid=47d05eca617756451240108503c101c5?query=auth:%22farag+h%22&page=1 http://europepmc.org/search;jsessionid=47d05eca617756451240108503c101c5?query=auth:%22mochida+i%22&page=1 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 471 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. unsupported catalyst operate at high activity and the sulfur reduce into less than 10 ppm (liu and zou 2013) studied experimentally the influence of aromatics addition on the hydrotreating (hdt) of oil residue. authors reported that the addition of aromatics enhanced the removal of heteroatoms and metals from oil residue. ferreria et al. (2014) investigated the effect of different feeds of crude oil (arabian light, buzurgan, and ural) on the reactions of hydrodesulfurization (hds) and hydrodemetalization (hdm) under industrial conditions using commercial catalysts. authors reported that properties of the feed have pronounced effect on the hdt efficiency. conimo catalysts with various content of promoters were used by (klimov et al., 2016) for hydrodesulfurization of gas oil. temperature equal to 390 o c and pressure equal to 90 bars were used to investigate the optimum proportions of active metals in the catalyst. abid et al. (2017) studied the influence of nspecies on hydrodesulfurization activity of srhn loaded with c4h4s compound, as a sulfidation agent, over como/γ-al2o3 in a fixed bed reactor at variable operating parameters (e.g., t= 593653 k, p= 2035bar, weigh hour space velocity = 2.5-5 h -1 , and (h2/oil) ratio = 60 vol/vol. with various concentrations of carbazole and pyridine. authors reported that conversion of sulfur increases as t and p increased. however the image of sulfur conversion with weight hour space velocity was different. authors revealed that hds efficiency was raised up in the following sequence: mixture of cabazole and pyridine < pyridine < carbazole. hydrotratment configuration of middle distillates in a modern petroleum refinery is characterized by severe operating conditions and sophisticated system which lead to high fixed and operating costs. simplification of such system was the goal of every process and design engineers. literature on hydrotrating of a mixture of middle distillates in a single hydrotrating reactor is scarce. in present work the proposed hdt process could be simplified as gas oil and lighter fractions (naphtha and kerosene); these mixture volumetric quantities, as have been present in crude oil. the gas oil and lighter fractions are hydrodesulfurization all at once in one hrt reactor to reach the sulfur specification of each oil fractions. next hds process, the reaction product is further separation into lpg, light naphtha, heavy naphtha, kerosene, and gas oil. thus the expected benefits from the proposed hdt method is the reduction of number of hdt reactors from three to one with their utilities (i.e., feeding and intermediate vessels, pumps, control systems, and systems used for heating, cooling, and purging). consequently, the fixed capital cost, and operational cost will be reduced. the highest objective of present study to investigate the feasibility of hydrodesulfurization of a mixture of middle distillate (e.g., naphtha, kerosene, and gas oil) in a single hydrotrating reactor under various operating parameters (e.g., temperature, pressure, liquid flow rate, and (h2/oil) ratio. study for the quality and productivity of products was conducted a comparison between the proposed method and conventional one for hds of middle distillates obtained from al-daura refinery/ baghdad. 1. matrials and methods 1.1. materials the commercial catalyst used was conimo/γ-al2o3 whose properties are listed in table (2). it was supplied from al_daura refinery/baghdad. gas oil and lighter fractions (mixture of naphtha, kerosene, and gas oil) was used as a real feed in all experiments for the hds process was supplied from al_daura refinery. gas oil and lighter fractions were obtained as one cut after separation of lpg and residue from basra medium crude oil at the atmospheric distillation column, al-dora refinery. the main properties of the feedstock (i.e. gas oil and lighter fraction) used in this work is listed in table (3). h2 gas (99.9 vol%) and n2 (99 vol%) gas were purchased from (al_mansoor co., iraq). table (2): specification of catalyst. chemical specifications units value moo3 wt. % 17 coo wt. % 2.7 nio wt. % 0.9 al2o3 wt. % balance al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 472 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. physical specifications surface area m 2 /g 160 pore volume cm 3 /g 0.43 bulk density kg/m 3 750 mean particle diameter mm 1.6 shape extradite table (3): feedstock properties (i.e., gas oil and lighter fractions). properties specification initial boiling point 30 ◦ c end boiling point 330 ◦ c api 45.37 specific gravity 0.80 density at 15 ◦ c 0.80 gm./cm 3 sulfur content 4341 ppm distillate boiling point range ◦ c vol.% light naphtha b.p range (30-122) ◦ c 14.5 vol.% heavy naphtha b.p range (80-180) ◦ c 24 vol.% kerosene b.p range (142-242) ◦ c 25 vol.% gas oil b.p range (200-322) ◦ c 36.5 vol.% 1.2. experimental setup the hydrotreating experimental apparatus which has been located at the petroleum research and development center, seen in figure (1), including a cylindrical reactor (i.d. = 17.5 x l=160 mm) made of stainless steel and heated by box shape electrical heater. the system have been also provided with indicators to measure the temperature of inlet liquid feed, inlet gas, reaction chamber, and heating mantel of reactor. middle distillates (i.e., gas oil and lighter fractions) were mixed in volumetric proportions, as have been produced from the atmospheric distillation unit of crude oil, and injected into the top of reactor by a dosing pump. the liquid middle distillates feed was preheated by an electric heater and mixed co-currently with hydrogen gas before it introduced into the top of reactor. the effluent from the bottom of reactor was sent to a cooler where reaction products condensed then sent to a high-pressure separator to separate gases (e.g., unreacted h2, nh3, and h2s) from liquid product which accumulated in a product tank and distillated in fractionation column to light naphtha, heavy naphtha, kerosene, and gas oil. the liquid feed and hydrogen gas were measured via calibrated digital flow meters installed on the feeding lines. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 473 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure (1): schematic of the hds setup. 1.3. experimental procedure the experimental procedure of this work was carried out in the following sequence: •drying process of catalyst. •sulfiding process of catalyst. •investigate the effect of process variables on hds efficiency of gas oil and lighter fractions. •investigate the effect of operating variables on the yield and product quality of liquid products (naphtha, kerosene and gas oil ). 1.3.1. drying process table (4) lists the operating conditions of the drying process. table (4): operating conditions of the drying process. operating conditions specification temperature 200 ◦ c pressure 10 bar n2 flow rate 160 nl/hr time 10 hr the moisture detected by measuring the output gas from the high pressure (h.p.) separator using moisture content measuring device (ap2-a100), the first sample was taken after two hours, the second sample was taken after ten hours of operation. when the moisture content of effluent gas was reached a value of (15 ppm), the drying process is considered completed (manual instructions of petroleum research and development center). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 474 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1.3.2. sulfiding process in this process the catalyst was activated by converting (conimoo4) into (conimos) form. in the present work, gas oil has been utilized for the sulfidation step with h2 gas. the concentration of sulfur in feeding stream was (4945 ppm). operating parameters of the sulfidation step were (t = 200-300 o c, p = 15 bar, light gas oil flow = 120 ml/hr, (h2/hc) ratio= 200 vol/vol, and time of sulfidation = 19 hrs). the operating instructions of the petroleum research and development center suggested that the sulfidation step is complete when a 0.05% increase in catalyst weight occurs. this increase in weight is attributed to the sulfur deposition over the catalyst surface. experimentally, it is decided that the sulfidation step is completed when the concentration of sulfur in the outlet stream equals to that in the inlet. figure (2a) and figure (2b) show the sulfidation procedure and the change in sulfur concentration at the outlet stream during the sulfidation step, respectively. figure (2a): sulfiding process steps at (p=15 bar, t= 350 o c, gas oil flow = 120 ml/hr and h2/oil =200). figure (2b): sulfur concentration in outlet stream as function of sulfidation time al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 475 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 1.3.3. hydrotreating process steps: figure (3): experimentally hydrotreating process steps. hydrotreating process for a mixture of gas oil and lighter fractions was conducted by:  loading the reactor with 50 gm of conimo-s/al2o3 depended on the selected values of whsv within the range of the values used in the industry scale (50 gm. of catalyst have the volume 66 ml and the total volume of reactor 77 ml the remain reactor volume was packed with inert particles (glass beads of ¼” diameter) at entrance and the bottom of reactor. this entrance section was employed to heat up the mixture to the required temperature and to ensure homogeneous flow distribution of gas and liquid.  n2 gas was fed over one hour to heat the environment inside the reactor.  prepared mixture of middle distillates was charged at the desired flow into the reaction chamber. to start the hds reaction, h2 gas was injected co-currently with the liquid mixture at the desired flow value.  reactor temperature starts to increase due to the heat liberated from the chemical reaction which controlled by the set value of the temperature controller that regulate the energy given by the heating elements of the box furnace.  set value of operating conditions for each run used for the hds process were (temperature = 310370 o c, whsv = 1.2 to 3.6 h -1 , pressure = 40 to 55 bar, and (h2/hc) ratio = 150 to 300 vol/vol).  products were cooled and distilled than analyzed for concentration of sulfur in each oil fractions.  the efficiency of the hds process was calculated from equation (1). ……………………………………. (1) 1.4. analyses techniques concentration of sulfur into inlet and outlet stream of reactor was measured using (xos analyzer, model sindie otg, usa). water moisture inside the reaction chamber during the drying step was measured using (meeco analyzer, model waterboy 2, usa). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 476 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2. results and discussion 2.1. influence of key parameters on hds % for a mixture of hcs 2.1.1. influence of (h2/hc) ratio variation of hds efficiency against (h2/hc) volumetric ratio for conimo-s/al2o3 keeping other operating parameters unchanged at (p=45 bar, t= 350 o c, whsv = 1.2 h -1 ), figure (4) is described variation of hds against (h2/hc) as (h2/hc) volumetric ratio increased from 150 to 200 nm 3 /m 3 , hds efficiency increased from 84 to 90% correspondingly. however, as (h2/hc) ratio increased from 200 to 300 nm 3 /m 3 efficiency of hds descended from 90 to 88.5% because decrease the contact time between the h2 gas and liquid hcs since h2 will flow at high rate. this revealed that the sulfur conversion plateaus at (h2/hc) ratio = 200 nm 3 /m 3 and a slight decrease for sulfur removal have been observed at higher h2/hc ratios. figure (4): effect of h2tooil ratio on hds efficiency for conimo-s/al2o3 at (p=45 bar, t= 350 o c, whsv = 1.2 h -1 ). similar results to those above were observed by (majak, 2010) and (bej, 2001). they found that the h2/hc ratio had an optimal value, depending upon the other process variables, after which a further increase in this ratio did not result in hds improvement. 2.1.2. influence of temperature the influence of temperature on efficiency of hds was investigated for conimo/al2o3 catalyst at the temperature and whsv ranges 310370 o c and 1.2-3.6 h -1 respectively at 50 bar and (h2/ hc) ratio of 200 vol/vol. figure (5) shows the outcomes. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 477 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure (5): influence of temperature on hds efficiency of a mixture of hcs at different whsv and constant (p= 50 bars and h2-to-hc ratio = 200 vol/vol) for conimo/al2o3. as can be observed, at constant pressure and (h2/ hc) ratio, the hds efficiency increased as temperature increased while whsv gives a different trend. at constant whsv=1.2, the hds efficiency is 86.4, 92, 95.8, and 96.2% when the temperature is 310, 320, 350, and 370 respectively. this effect of temperature on hds efficiency may be due to the positive relationship between operating temperature and the reaction rate constant as stated by arrhenius equation. the increase in hds efficiency is rapid up to a temperature of about 350 o c; this may be attributed to the chemical equilibrium of reversible reactions which attained at higher reaction rates at high temperature. beyond this temperature the increase in hds efficiency is negligible. for example, at whsv=1.2 the rate of increasing of hds% is 9% when the temperature raised from 310 to 330 o c, while the increase in hds is 1% when the temperature raised from 350 to 370 o c. this may be attributed to the chemical equilibrium of reversible reactions which are achieved at higher temperatures. 2.1.3 influence of whsv whsv is a useful parameter in design and scale-up of continuous flow reactors. in the present study the selected whsv values (1.2-3.6 h -1 ) were within the range of the values used in the industry (kunda et al., 2003). the influence of the whsv on hds efficiency of a mixture of hcs is illustrated in figure (6) for conimo/al2o3 catalyst at the temperature and whsv ranges 310370 o c and 1.2-3.6 h -1 respectively at constant pressure = 50 bars and (h2/ hc) ratio of 200 vol/vol. the selected whsv values (1.2-3.6 h -1 ) were within the range of the values used in the industry (kundu, 2006). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 478 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 70 75 80 85 90 95 100 h d s % t=310 c t=330 c t=350 c t=370 c figure (6): effect of whsv on hds efficiency of a mixture of hcs at different reaction temperature at constant (p = 50 bars and (h2/hc) ratio = 200 vol/vol) for conimo/al2o3. figure (6) shows that a decrease in whsv results in an enhanced hds efficiency. the sulfur content decreases and inversely the produced h2s gas increases. at temperature = 350 o c, hds efficiency is 81, 87, 91 and 95.8% as the whsv is 3.6, 2.8,2 and 1.2 h -1 respectively. it was observed that at constant temperature = 350 o c and pressure = 50 bars, increasing whsv from 1,2 to 3.6 h -1 decreased hds% by 12.5%. this may be attributed to the contact time between reactants and catalyst which increases as the whsv decreases, hds efficiency is increased correspondingly. 2.1.4 influence of pressure the influence of the pressure on hds efficiency of a mixture of hcs is illustrated in figure (7) for nicomo/al2o3 catalyst at the pressure and whsv ranges 4055 bars and 1.2-3.6 h -1 respectively at 350 o c and (h2/ hc) ratio of 200 vol/vol. figure (7): variation of hds % against pressure at different whsv at constant (t = 350 o c and h2-to-hc ratio = 200 vol/vol) for conimo/al2o3. in figure (6) , hds efficiency is enhanced by increasing the pressure, this enhance in hds% may be refer to the desulfurization of some refractory molecules (i.e., dbt) which proceeds only at very high pressures(sidhartha ,2011). at whsv=1.2, the hds efficiency is 87.4, 91, 95.8, and 96.4% when the al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 479 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. pressure is 40, 45, 50, and 55 respectively. moreover, figure (6) reported that when the pressure raised up from 50 to 55 bar the enhancement in the hds efficiency is negligible. this could be due to the phenomenon of pores saturation which becomes effective when the pressure attained high values. this saturation reduces the effect of any increase in pressure on hds improvement. furthermore, figures (5) and (7) revealed that the influence of temperature on sulfur removal is dominant over pressure. 2.2 comparison between conventional and proposed methods 2.2.1. yield analysis table (5) shows the experimental results of the feed and product compositions for the proposed hydrotreating reactor. s indicated sulfur removal of high molecular weight compounds increases as operating temperature increases and w v decreases. t is seen that at t 330 c with various values of whsv, the products composition kept constant which indicates that the conversion of high molecular compounds can be performed only at more severe conditions. however, it well known that mild hydrocracking (mhc) takes place in the same time with hds at the temperature range of 350°c to 370°c. more conversion of high molecular weight compound to lower molecular weight compound is occurred at higher temperature and lower whsv. table (4) lists the results of distillation for product of proposed hds. 2.2.2 comparison of product quality figure (8) illustrates comparative results for yields of the proposed and traditional methods at optimal values of process variables. (p = 50 bars, t= 350 o c, and whsv = 1.2 h -1 ). as can be seen from figure (7) , the production of l.naphtha, h.naphtha, kerosene, and gas oil was almost the same for both methods. as indicated in figure (8), there is a 1.6% reduction in gas oil less than that of conventional method. however, kerosene, heavy naphtha, and light naphtha undergo increases of 0.6%, 0.75%, and 2.75% respectively over these from conventional method. these results indicate that the quantity of fractions is almost the same for both methods. table (6) and table (7) list the main properties of middle distillates yielded by traditional and proposed methods, respectively. this analysis was performed to detect any deviation in properties for fractions produced by the two methods. as can be seen from table (6) and table (7) that the results obtained confirmed the properties match of fractions yielded by the two methods. however, api for the fraction yielded by proposed method is somewhat higher than api of the same fractions yielded by traditional method, which suggests an upgrading in properties of these fractions. table (5): yield analysis results. temperature lumps whsv (hr -1 ) 0 2.8 2 1.2 feed (wt. %) products (wt. %) ln 4.96 4.96 4.96 4.97 hn 9.28 9.28 9.28 9.29 330 o c kerosene 9.99 9.99 9.99 9.99 lgo 16.60 16.60 16.60 16.58 ln 4.96 4.97 5.00 5.10 hn 9.28 9.29 9.30 9.35 350 o c kerosene 9.99 9.99 10.00 10.05 lgo 16.60 16.58 16.53 16.32 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 480 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. ln 4.96 5.00 5.01 5.11 hn 9.28 9.30 9.32 9.36 370 o c kerosene 9.99 10.00 10.02 10.05 lgo 16.60 16.53 16.48 16.31 figure (8): percentage weights of middle distillates yielded by proposed and traditional method. table (6): specification of distillate fractions yielded by traditional method. property distillate fractions l.naphtha h.naphtha kerosene l. gas oil api@15.6 0 c 83.5 60.2 48.0 41.4 sp.gr @ 15.6 0 c 0.6581 0.7381 0.788 0.8183 distilled (vol.) 0 c 0 c 0 c 0 c i.b.p 35 80 160 195 5 % 38 88 172 225 10% 40 98 180 235 20% 48 106 185 252 30% 52 112 190 260 40% 56 118 195 268 50% 60 124 200 275 60% 65 130 205 285 70% 70 135 210 290 80% 75 140 215 295 90% 86 145 225 305 95% 98 152 235 315 ep % 120 174 250 325 4.96 5.1 9.28 9.35 9.99 10.05 16.6 16.32 0 2 4 6 8 10 12 14 16 18 20 conventional hdt present study w t. % l.n h. n kerosene gas oil al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 481 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. table (7): specification of distillate fractions yielded by proposed method property distillate fractions l.naphtha h.naphtha kerosene l. gas oil api@15.6 0 c 84.4 62.7 48.7 40.5 sp.gr @ 15.6 0 c 0.6553 0.7286 0.7852 0.8226 distilled (vol.) 0 c 0 c 0 c 0 c i.b.p 30 80 165 200 5 % 36 90 170 220 10% 40 100 175 236 20% 45 108 182 258 30% 48 116 195 265 40% 54 122 198 270 50% 55 128 202 275 60% 62 132 206 280 70% 68 138 212 288 80% 75 142 218 295 90% 85 147 225 300 95% 94 155 230 312 ep % 122 176 252 322 2.3. statistical analysis and kinetics models the interaction of parameters, optimum operating conditions, and regression models for predicting the percent conversion of sulfur in hds process to obtain optimum hds % are estimated using analysis of variance (anova) technique. two statistical tests (test of significance of factors and r 2 test) were used to evaluate how well the experimental data was represented by the models: 1test of significance of factors means that insignificant factors or interactions must be excluded from the model. significance of the factors or the interactions is evaluated using p-value (probability value). when the p-value of a factor or an interaction is greater than 0.05, then this factor or interaction is considered insignificant and can therefore be excluded from the final mathematical model. 2r 2 test, a value that always falls between 0 and 1, is the relative predictive power of a model. the closer to 1 the r 2 is the better the model represents the experimental observations. adjusted r 2 is a modification of r 2 , but unlike r 2 it only increases when the newly included factor(s) or interaction (s) are significant. another quantity is predicted r 2 . while r 2 indicates how well the model fits the experimental data at hand, predicted r 2 indicates how well the model predicts responses for new observations. analysis of the experimental results was carried out using design-expert 10.0.6.0 to optimize the considered operating conditions with respect to hds %. the factorial design method was used for planning the experiments, because of its reliability in finding the effects and interaction between the controlled variables (p, t and whsv) of the operating system. table (8): independent variables with their coded and actual values factor real symbol units minimum limit maximum limit no. of levels (l) x1 p bar 40 55 4 x2 t c 310 370 4 x3 whsv hr-1 1.2 3.6 4 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 482 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. regression analysis of experimental data generated equation (2) which represents a polynomial related the objective function (i.e. %hds) to the studied operating variables with correlation coefficient (r 2 ) = 0.9955; adj. r-squared = 0.9935; and pred. r-squared = 0.9871. the "pred. r 2 " is in reasonable agreement with the "adj. r 2 " with difference less than 0.02. % hds = -530.2264+ 11.2045 p + 1.8329 t – 8.4586 whsv – 5.5833x10 -3 p x t + 0.1458 p x whsv – 0.0104 t x whsv –.08887 p 2 2.0471x10 -3 t 2 – 0.1075 whsv 2 ............................. (2) equation (2) can be used to make predictions about the response for given levels of each factor. here, the levels should be specified in the original units for each factor. the models predicted with reasonable accuracy the experimental results (with r 2 > 0.99). figure (9) compares the actual value and predicted value of hds% response. figure (9): compares the actual value and predicted value of hds% response. the p-test was used to test the significance of factors and interactions between the parameters for hds models. table (9) lists the results of the ptest. table (9): results of test of the significance of factors and interactions for hds models. anova analysis for response surface quadratic model source fvalue p-value model 513.09 < 0.0001 significance p 1417.64 < 0.0001 + t 510.35 < 0.0001 + whsv 2244.69 < 0.0001 + p*t 26.52 < 0.0001 + p*whsv 28.94 < 0.0001 + t*whsv 2.36 0.1392 * al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 483 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. p 2 253.46 < 0.0001 + t 2 34.52 < 0.0001 + whsv 2 0.24 0.6265 * +: significant; *: insignificant table (9) demonstrates the evaluated f-value and the corresponding p values. the single-factor term represents a linear effect of the corresponding factor, while the two factors represent the interaction between the two factors. additionally, the second order term represents a quadratic effect towards the response. the p value serves as a tool to check the significance of each coefficient at a specified level of significance. the higher the t-value or the smaller the p value, more significant the corresponding coefficient. generally, a p value of less than 0.05 is considered to be very significant and contributes largely towards the responses. as observed in table (9) , the terms p, t, whsv, p x whsv, p 2 , and t 2 are significant model terms. however, the terms of values greater than 0.1000 are considered insignificant. in this case reduction of the terms t x whsv, and whsv 2 may improve hds model. 2.3.1. optimum operating conditions based on the studied operating variables, the best values to obtain the optimum hds% are estimated using design-expert 10.0.6.0 software. figure (10) shows the location of the optimum conditions using the design-expert software. figure (10): best values of the studied operating conditions to obtain optimum hds%. conclusions simplification of the hdt system was the goal of all process and design engineers of the field. in the present work a single hdt reactor was proposed for hds of a mixture of naphtha, kerosene, and gas oil produced from atmospheric fractionation unit at al-dora refinery. experimental results showed that temperature and pressure have a positive effect on process performance while weight hour space velocity gives a different trend. results showed that the best values to obtain the optimum hds% are estimated using design-expert 10.0.6.0 software (350 o c, 50 bars, 1.2 h -1 , and 200 vol/vol), the al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 484 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. hydrodesulfurization (hds) efficiency was 95.8%. maximum sulfur conversion of (95-96) % was obtained at pressure range (50-55) bars. this increase in hds efficiency may be attributed to the desulfurization of some refractory (i.e. dbt) molecules which proceeds only at very high pressures. quantitative and qualitative analysis for the products from the proposed hdt method confirmed the feasibility and applicability of the method. the production of l.naphtha, h.naphtha, kerosene, and gas oil, there is a 1.6% reduction in gas oil while kerosene, heavy naphtha, and light naphtha increases of 0.6%, 0.75%, and 2.75% respectively over these from conventional method. according to statistical analysis (i.e. p-values) the significance order of the independent variables on the maximum obtained hds activity is operating pressure then reaction temperature however, the effect of weight hour space velocity terms on hds activity is less statistically significant. the obtane models predicted with reasonable accuracy the experimental results (with r 2 > 0.99). acknowledgement researchers are thankful to the school of chemical engineering, university of technology for assistance in completion of this work. the fund which has been awarded by the petroleum research and development center is highly appreciated. references 1. abid m.f., abdullah m.k., ali s. m. 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(2013) “effects of aromatic cycle oils on performance of residue hydrotreating”, korean j. chem. eng. 30(11), 1985-1989. http://europepmc.org/search;jsessionid=47d05eca617756451240108503c101c5?query=auth:%22farag+h%22&page=1 http://europepmc.org/search;jsessionid=47d05eca617756451240108503c101c5?query=auth:%22mochida+i%22&page=1 http://europepmc.org/abstract/med/22297022 http://europepmc.org/abstract/med/22297022 http://europepmc.org/search;jsessionid=47d05eca617756451240108503c101c5?query=journal:%22j+colloid+interface+sci%22&page=1 http://europepmc.org/search;jsessionid=47d05eca617756451240108503c101c5?query=journal:%22j+colloid+interface+sci%22&page=1 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 485 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 13. rana m.s., rufino n., jacques l. (2004). “competitive effects of nitrogen and sulfur content on activity of hydrotreating como/al2o3 catalysts: a batch reactor study”, catalysis today 98, 67–74. 14. sidhartha mohanty (2011) “ effect of citric acid on hydrotreating activity of nimo catalysts” masters of science , department of chemical and biological engineering ,university of saskatchewan. 15. speight (2010) “fundamentals of petroleum and petrochemical engineering”, chemical industries, taylor & francis groupin the united states of america. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 164 performance prediction of rotating biological contactor in wastewater treatment applications abstract: biofilm models were used to model and predict the performance of rotating biological contactors (rbc) in wastewater treatment plants. assessment techniques have been adopted to evaluate this method in terms of hydraulic loading and biochemical oxygen demand (bod) removal. the results revealed that rbc not only is efficient, but also proven to be odor controlling reactor. rbc provides efficient mixing and reduces time of retention to minimum, so that a great reduction of area of treatment plants will be achieved. key word: bod, cod, organic material, wastewater, biofilm. /��x=ا<داء���pgا����� ا� ���� �rت ا� �$���e�� ا��وارة � ��qت ���� :ا�567 ���$���� � ���-�� ����� ��� �)�� ���� j��� �$���� ��)� &����� ��$���� � ���mk -���� % �3�� %� �� ��� . ���n� �� �� &-3 � �)�� � o��� a�b %�/� 0�$ &�� �� �p �q��� *�� ��������5� &��)�� &���� bod . ��$���� � < �'k ��� ����� %�/� 0�$ %� )bio-disks ( ������ �q��� *�� 2 � �� ��� l:��� �5� � �� ������ �q��� #��� ���� �$��� �� ��� ��$���� � ���-�� �5//)� ��� ��$� ��3� ����� ! &��)�� ��$��� a��� &��� q��� � ����� � �)���� & ��3 *�! c�r� ������ � �$������ g����� q�/ � �� &�/�� s���� &�� �)�� . dr. amer d. zmat college of engineering al-qadisiya university dr. ali h. ghawi college of engineering al-qadisiya university ا�2آ��ر �1�) د��م ز��ط �2 آ* ا�3 ����� ا���د ا�2آ��ر 1*� ه�دي /�وي �2 آ* ا�3 ����� ا���د al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 165 nomenclature a a lumped parameter which is equal to f f d kx , mg⋅l−1 aw surface area of the disk, m 2 a the slope for 0=z f dz ds as expressed to be a linear correlation with sb, m −1 b the intercept for 0=z f dz ds as expressed to be a linear correlation with sb, kg⋅m−4 df diffusion coefficient of substrate within the biofilm, cm 2⋅h−1 ki constant for inhibition, mg⋅l−1 ks saturation constant, mg⋅l−1 k maximum specific substrate consumption rate, s −1 lf biofilm thickness, mm lt length of the reactor, m q flow rate, m3⋅d−1 ra substrate consumption rate by the microbes attached on the disc, kg⋅m−2⋅s−1 s substrate concentration, mg⋅l−1 s0 substrate influent concentration, mg⋅l−1 sb liquid phase substrate concentration, mg⋅l−1 se substrate effluent concentration, mg⋅l−1 introduction rotating biological contactor (rbc) has been widely used for the secondary treatment of domestic and industrial wastewaters. the rbc consists of a series discs attached to a common shaft. the wastewater is fed into the contactor with a certain flow rate. all the discs are partially submerged into the wastewater. when the discs are continuously rotated by the shaft, a subsequent submergence and exposure to atmosphere will take place. thus, the microbial film on the disc that is initially in contact with the nutrients of the wastewater phase and then with the oxygen in the atmosphere. hence, the organic compounds in the wastewater would serve as the nutrients for the microbes to digest and grow. by such periodical operation, the microbes would grow and a certain sludge film thickness would be obtained. the rbc is used because of its advantages such as high specific surface area, high activated sludge concentration, better sludge settling, process stability, and low maintenance and power consumption. benefield and randall [1] described the design of the biological treatment processes for wastewaters [1]. two pilot-scale rbcs with pe discs arranged in four stages were used [2] for the treatment of 2-nitrophenol or 2-chlorophenol contained synthetic wastewater. opatken and bond [3] treated a leachate with high concentration of ammonianitrogen (20-1000 mg/l) by the nitrification process with a pilot-scale rbc. different experiments were conducted to determine the operating parameters of the rbc treatment system. buisman et al. [4] compared three different bioreactor systems for the removal of sulphide containing wastewater. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 166 stirred reactor, biorotor reactor and upflow reactor were used for comparison. the biomass support materials of rasching rings and polyurethane were also compared. it is obvious that the biofilm disc is very important for the rbc performance. brower and barford [5] introduced different biological fixedfilm systems in their report [5]. in 1978, a theoretical model for rbc systems was provided so that process design criteria for a pilotplant rbc process can be established and be compared with the activated sludge process [6]. since rbc is composed of a series of discs with microbial growth in a film. the film model is certainly important for it. mass transfer problems across the film should also be taken into consideration. the steady-state biofilm kinetic models were proposed for both conditions of deep and shallow biofilms [7]. in the adopted model, mainly monod growth model with substrate diffusion along single dimension was assumed. the film was assumed to be of a planar form. the substrate flux was also discussed. the deep biofilm model with monod assumption for completely mixed and plug flow biofilm reactors was analyzed [8]. such biofilm reactors were found to be extremely sensitive to the surface parameters. models are based on monod growth kinetics. activated sludge reactors and rotating biological contactors demonstrated that both suspended and attached growths can be effective methods for treating the wastewater as described above. sagy and kott [9] examined fecal coliform bacteria and salmonella typhimurium die-off in an experimental rbc which received settled domestic sewage from the city main sewer. the behavior of the microbes on the biofilm is fairy important. most biofilms are formed by mixed species. gupta and gupta used a mixed culture aerobic biofilm to remove carbon and nitrogen from a synthetic domestic sewage [10]. rbc is an essential treatment process for treating industrial wastewater. meanwhile, it is also a very interesting system for theoretical analysis. hence, in this work, we established the model for the biofilm system based on both mond and substrate inhibition mechanisms. with the models, the operation conditions as well as the number of the biofilm discs can be analyzed developed of mathematical model the biofilm reactor being considered has a length of lt and a flow direction parallel to the horizontal axis as shown in fig. 1. the schematic representation of a biofilm is shown in fig. 2. it was assumed that the fluid was well-mixed in the radial direction and the substrate consumption from the suspended microbial can be negligible when compared to that of the attached biofilm. consider an infinitesimal volume in a biofilm reactor, by the mass balance for a shell, where vt is the volume of wastewater in the biofilm reactor, lt is the length of the reactor, ra is the substrate consumption rate by the microbial attached on the disc, sb is liquid phase substrate concentration, and q is the flow rate. if we divide both sides of equation 1 by ∆y, we obtain (1) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 167 if the substrate consumption rate by the attached microbial on the disc is equal to the substrate diffusion rate at the surface of the film, then, where df is the diffusion coefficient of substrate within the biofilm, sf is the substrate concentration in the biofilm, and z is the axis along the biofilm thickness. under steady state assumption the following boundary conditions were implemented to solve equation 4. 1. the boundary conditions in case of thick biofilm: for the case of thick biofilm with monod kinetics µ = µm s/ks + s. where f f d kx a = and k is the maximum specific substrate consumption rate [t −1 ]. for the case of the thick film with substrate inhibition kinetic (1) if ki/ks < 4, then (2) (3) (4) (5) (6) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 168 (2) if ki/ks > 4, then (3) if ki/ks = 4, then substituting the above equations (eqs. (5)-(8)) into eq. (4), we obtain the following results, • without substrate inhibition: • with substrate inhibition: (1) if ki/ks < 4, (2) if ki/ks > 4, (3) if ki/ks = 4, the above equations are all first-order ordinary differential equations. they can be solved for the numerical solution of sb|z=l, which is the exit substrate concentration, se, by the fourthorder rungekutta method. (7) (8) (9) (10) (11) (12) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 169 2. the boundary conditions in case of thin biofilm: sf and 0=z f dz ds can be solved by finite difference and the exit substrate concentration sb |z=l can be further obtained. based on the above theorem and assumptions, the effluent substrate concentration can be computed. during the computation process, several operation conditions, which draw influence on the performance of the biofilm reactor, such as influent substrate concentration, length of reactor, total surface area of the biofilm, flow rate, numbers of reactors in series, film thickness should be provided. the growth and diffusion parameters related to the biofilm such as ks, ki, k, xf , and df should be given as well. for the thin biofilm, under monod kinetics assumption, when the substrate concentration in liquid phase is higher, the substrate consumption rate ra would be higher as well. for substrate inhibition kinetics assumption the result is similar, which is higher substrate consumption rate for higher liquid phase substrate concentration. however, when the substrate concentration is too high, substrate inhibition would cause the decreasing of substrate consumption rate. it can be inspected from fig. 3 that under certain range of sb, 0=z f dz ds (ra) is a linear function of sb for the case of thin film. therefore, 0=z f dz ds can be expressed as bsa dz ds bz f +== .0 where a is the slope and b is the intercept. a and b are dependent on the range of sb. provided that the liquid phase substrate concentrations were sb,1 and sb,2 , then, (13) (14) (15) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 170 combining eqs. (14) and (15), a and b can then be obtained. substituting eq. (13) into eq. (4), then, results and discussion six stages biofilm reactors for wastewater treatment was considered in the following analysis. both monod kinetic and substrate inhibition kinetic were applied in this study. the length of the biofilm reactor was set to be 5.0 m. the total surface area for treatment was 5,000 m2. kinetic parameters for cell growth were ks = 100 mg/l and xf = 20,000 mg/l. the diffusivity of the biofilm was df = 0.02 cm 2 /h. flow directions of the influent feed were set to be parallel to the horizontal axis of the reactor. for flow direction parallel to the axis, the biofilm reactor maybe regarded to be a plug flow reactor (pfr). the bod removal efficiency was evaluated in terms of inlet substrate concentration at different hydraulic loadings, as shown in fig. 4. the results show that higher hydraulic loadings exhibit higher bod removal efficiency at low inlet substrate concentration whereas, lower hydraulic loadings can result in very low bod removal efficiency at higher inlet substrate concentration. fig. 5 shows that increasing the number of bio-disks can steeply reduce the effluent substrate concentration for different inlet substrate concentration. these results may be used by designers to determine the required number of disks for specific inlet and outlet constraints. fig. 6 shows that law inlet substrate concentration slightly affect the substrate removal efficiency when hydraulic loading increased, while high inlet concentration can cause significant drop in the removal efficiency as a threshold value in exceeded. it can be seen from fig. 7 that low inlet substrate concentration is very sensitive to the number of bio-disks, whereas, higher inlet concentration show gradual response to the number of bio-disks. the cod removal in terms of hydraulics loadings was compared to bod removal. figure 8 below was adopted from [11] for comparison. the effect of hydraulic loading on cod removal efficiency was also adopted from [11 ] to be compared with the bod removal efficiency. figure 10 shows that dissolved oxygen is steeply declined as the thickness of the biofilm increases. this interprets that the process is diffusion-controlled. the submergence ratio of bio-disks was investigated in terms of the dissolved oxygen and number of stages of the process ( fig. 11). submergence ratios between 0.4 and 0.6 were found to appropriate and effective than higher and lower ratios. conclusion (16) (17) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 171 based on monod kinetics and substrate inhibition kinetics for the biofilm, the model for the substrate removal efficiency of a 6 stage biofilm reactor was established. the influence of feeding rate, hydraulic loading and organic loading rate (hydraulic retention time) was investigated and discussed. rbc technology was found to be cost effective in wastewater treatment as it considerably reduces both the size of equipments and the number of unit operations. references [1] benefield, l. d. and c. w. randall, biological process design for wastewater treatment, prentice hall, new york, u.s.a. (1980). [2] tokuz, r. y., “biodegradation and removal of phenols in rotating biological contactors,” water sci. technol., 21(12), 1751 (1989). [3]opatken, e. j. and j. j. bond, “rbc nitrification of high ammonia leachates,” environ. prog., 10(1), 60 (1991). [4] buisman, c. j., b. wit, and g. lettinga, “biotechnological sulphide removal in three polyurethane carrier reactors: stirred reactor, biorotor reactor, and upflow reactor,” water res., 24(2), 245 (1990). [5] brower, j. b. and c. c. barford, “biological fixed-film systems,” water environ. res., 69, 487 (1997). [6] clark, j. h., e. m. moseng, and t. asano, “performance of a rotating biological contractor under varying wastewater flow,” j. water poll. control fed., 50, 896 (1978). [7] rittmann, b. e. and p. l. mccarty, “model of steady-state-biofilm kinetics,” biotechnol. bioeng., 22(11), 2343 (1980). [8] suidan, m. t. and y. t. wang, “unified analysis of biofilm kinetics,” j. environ. eng., 111(5), 634 (1985). [9] sagy, m. and y. kott, “efficiency of rotating biological contractor in removing pathogenic bacteria from domestic sewage,” water res., 24(9), 1125 (1990). [10] gupta, a. b. and s. k. gupta, “simultaneous carbon and nitrogen removal in a mixed culture aerobic rbc biofilm,” water res., 33(2), 555 (1999). [11] kossay k. al-ahmady" effect of organic loading on rotating biological contactor efficiency"int. j. environ. res. public health, 2(3), 469-477 (2005). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 172 figure 1. schematic represent of a biofilm reactors. figure 2. schematic representation of a biofilm. figure 3. representation of biofilm reactors (plug flow reactor pfr) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 173 figure 4: substrate (bod) removal efficiency with respect to inlet concentration under different flow rates and 3 mm biofilm active thicknesses. figure 5: effluent substrate concentration with respect to number of biofilm disks under different substrate inlet concentration al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 174 figure 6: effect of hydraulic loadings on the substrate removal efficiency at law and high inlet substrate concentrations. figure 7: effect of the number of bio-disks on substrate removal efficiency at different inlet al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 175 figure 8: effect of hydraulic loading on % cod removal. figure 9: effect of organic loading on the cod removal efficiency al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 176 figure 10: concentration profiles of organic substrate, and dissolved oxygen inside the biofilm in rbc stages figure11: the do concentration in bulk liquid under varying submergence ratio in rbc stages article al-qadisiyah journal for engineering sciences 12 (2019) 199–206 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: safa.saib89@gmail.com (safa s. kadhim) https://doi.org/10.30772/qjes.v12i4.621 1998-4456/© 2019 university of al-qadisiyah. all rights reserved. steel stiffeners for enhancement of slab-column connections safa s. kadhima* and haider k. ammash a a university of al-qadisiyah, college of engineering, iraq a r t i c l e i n f o article history: received 09 october 2019 received in revised form 18 november 2019 accepted 20 november 2019 keywords: column capital steel stiffeners finite elements flat slab punching shear strength. a b s t r a c t this paper introduced a strengthening technique for flat plates using steel stiffeners. in this paper, the effectiveness of steel stiffeners with different arrangements and numbers on the punching shear strength. the strengthening steel plates were extended from column to the slab and acted as a column capital of an equivalent concrete column capital. the study was divided into two parts, the first part was the experimental study involves the molding three reinforced concrete flat slab strengthening with different dimensions and numbers of steel stiffeners, with changed the dimensions of steel plates for specimens (ss1 (100×100mm), ss2 (200×200mm), and ss3 (300×300mm)) in addition to reference model without strengthening. the loadcapacity of the strengthened slabs was increased by (39.84%, 57%, and 99.2%) respectively over that of the control specimen with slabs (ss1, ss2, and ss3). the second part that numerical modeling through the abaqus finite element program was introduced. effect of the steel stiffeners' size and the effect of the column's shape (rectangular and circular) that's deal with steel stiffeners were studied experimentally and numerically. a good agreement was obtained between the experimental and theoretical results. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction slab-column connections are concrete reinforcement slabs with a uniform thickness that transfer loads direct to the support column and are differentiated from other (two-way) systems due to the absence of column capitals, beams, and drop panels. slab column connections have many advantages such as economical formwork, simple reinforcement layouts that's lead to fast construction. from an architectural point of view, the slab column connections can be used to achieve a smaller overall story height due to the required depth of the low floor structure, and the position of the column and wall is not limited to the position of the beam. however, this type of slab is susceptible to a brittle failure due to punching stresses, highly inducing around columns. when the loads far below the slab flexural strength of the carrier plate are applied, this causes the punching shear failure to be suddenly guan and loo [1]. the failure of a slab-column connection was described off with the term 'punching'. it is correlated to a special failure mechanism in which the column containing part of the slab are pushed together through the slab alexander and simmonds [2]. there are many effective methods to enhance the punching shear strength of slab-column connections. shear reinforcement is one of the methods to increase the punching shear strength. there are different types of shear reinforcement systems such as (steel offcuts, head stirrups, stirrups or shear links, shearheads, bent-up bars, and closed stirrups). a lot of research has been conducted to investigate several techniques for strengthening a flat slab by using several materials to reinforce structural components. some of the researchers study the influence of using of increasing the thickness of slab on punching shear strength such as lips et al. [3], the result showed that the increase in slab thickness would develop the punching strength for the specimens (pl4, pl5) with the thickness (320, and 400 mm) respectively about (67% and 156%) compared with control specimen pv1 with the thickness (250 mm). other researchers like mabrouk et al. [4] noticed the increasing the punching shear capacity by the addition of steel reinforcement. when the reinforcement of steel bars was added (5ø12 mm) at the tension side to avoid flexural failure to the main reinforcement consisted of steel bars with (ø10 mm), the result had http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 200 kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206 shown when the reinforcement ratio was improved about (20%, 45%) the ultimate punching shear enhanced about (6% and 16%) respectively compared to the control specimen. qassem et al. [5], studied the influence of using the shear-head reinforcement on the capacity of the punching shear by tested fourteen specimens with embedded shear-head, the specimens with (1000×1000×70 mm) dimension for the slab and (150 ×150 mm) dimension for the column. as a result, discovered that the use of steel plates led to a decrease in ultimate shear stress of about 44%, 40%, 19%, and 30% respectively, and the increase in dimensions of the steel plate enhances the ultimate load capacity. also, the increase in dimensions of the steel plate leads to an increase in the concrete strain in the tension face of the concrete slab and the critical section perimeter. al-wetaefi [6], investigated the influence of using hsc with shear reinforcement (bent bars) on the behavior of punching shear strength for the slab-column connection. the shear reinforcement (bent bars) sit at distance (0.25d) from the column surface, and the bent bars at the middle was inclined leg at 45°. as a result, showing that bent bars improve the deformation capacity and the ultimate punching shear capacity for the slab-column connections about 20% and 1.86% respectively at contrasted with reference specimens. hassanzadeh and sundqvist [7], investigated the effect of using doubling and tripling column diameter for column capital. this method of strengthening increased the capacity of punching shear about 60% and100% respectively, related to the control slab. reinforcement rings worked to prevent the stress of tensile that formed in the column head and to keep the shotcrete at the position through the form of a column head. besides, using the steel collars attached to the slab and the column worked as a column capital. the strengthening by the steel collars increased the punching capacity of about (70%) concerning the reference slab. widianto [8], used the enlarging column part technique to strengthen punching shear, in this technique used the steel collar underneath the slab. the steel collars were formed as the steel tube. as a result of this strengthening, the collar was enhancing the punching shear capacity because of increasing the perimeter critical shear. the punching shear capacity increased about 45% and the deformation capacities increased about 53% for flexural reinforcement ratio (0.5%) and flexural reinforcement ratio (1.0%) the punching shear capacity increased about 42% and the deformation capacities increased about 15%. ramos et al. [9], introduces a strengthening technique of two-way slab by using a steel plate and steel bolt. use eight steel bolts to transfer horizontal forces from the plate to the concrete. the steel plates were formed as two l-shaped plates welded together after being put into place before inserting the steel bolts. before strengthening the slabs were loaded up to 50% from the ultimate capacity of the control slab. the result investigated that plates must surround the column face at the distance least twice from the depth of slab estimated from the face of the column, the least number of bolts must be equal to eight and the minimum plate thickness should be 6 mm. ammash [10] taken into account in their model compressive strength of concrete, slab depth, the ratio of the flexural reinforcement at the critical section, shape, and dimension of the column, and the position of the critical section. they observed that the flexural reinforcement ratio influence the capacity of the punching shear, the result has shown the increase in the punching shear strength by (17%) at the increasing the flexural reinforcement ratio from (0.6%) to (2.2%). ammash [11] study the effect of using reinforced concrete column capital on the punching shear strength of the flat slab. the study was divided into two lines, the first line was the experimental study involves the molding four reinforced concrete flat slab models with dimensions (1600×1600×100mm) with three different dimensions of column capital (400×400mm, 600×600mm, and 800×800mm) in addition to reference model without columns capital (column dimension 200×200mm). the second line that numerical modeling through the abaqus finite element program was introduced. the effect of the column’s capital size and shape of the column’s capital (rectangular and circular) were studied. this paper presented, the experimental and numerical results to study the influence of using steel stiffeners to strengthen reinforced concrete slabs against punching shear failure. and also to investigate the performance of the strengthening technique for increasing the perimeter critical section of punching shear by using steel stiffeners. 2. experimental program for slab-column connections were made to describe the experimental part of the investigation. three connections were strengthened by steel plates and stiffeners, which were installed around columns. the primary test variables were the dimensions and several steel plates and stiffeners. flat slabs which formed as a square shape, having a dimension of (1600mm) and thickness of slab (100mm) with the square column have a dimension of (200 mm). all slabs had the same dimensions and flexural reinforcement equal to the (1.26%) as well as similar material properties, such as concrete strength (25 mpa) and also designed to fail in punching shear. the flat plates were reinforced with φ10-bars, spaced 200 mm center-to-center. the measured effective depth was 70 mm. the yield strength of the tensile reinforcing steel was 635 mpa, and the ultimate tensile strength was 713 mpa was determined experimentally for all specimens. where the steel stiffeners with steel plate work as column capital, the steel plate was used with (6mm) thickness and size was taken to represent the distance from the column face to the edge of the plate ( h, 2h, and 3h) for the specimens (ss1, ss2, and ss3) respectively where h is the thickness of slab (h=100 mm). the dimensions of steel plates were 100x100x100, 200x200x200, and 300x300x300 for specimens ss1, ss2, and ss3, respectively. figure 1 shows the geometry and details of flat slabs under investigation. the investigation focused on comparing the maximum performance of reinforcement slab flat systems with different sizes and number of steel stiffeners. a (sr) b (ss1) c (ss2) d (ss3) figure 1. geometry and details of flat slabs kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206 201 3. strengthening procedure the experimental program of this study includes three specimens that strengthening by using (steel plate and stiffeners) configurations and bolt distribution patterns were provided as shown in figure 2. the steel stiffeners were used with different numbers at the specimens, where there was one stiffener used in each side of column at the specimen (ss1), two stiffeners used in each side of column at the specimen (ss2), and in the specimen (ss1) was used three stiffeners used in the each side of the column. the steel plates for slabs were four l-shaped plates put into place by inserting the steel bolts and also the steel stiffeners have the triangular shape is put into the middle of the plate and welded together with the steel plate, the steel plate works as a rigid region at the maximum shear position and flexural stress. the rigid region works like the new column capital of comparable concrete of column capital. the reference specimen (unstrengthen) sr, was examined to evaluate the ultimate load and the deflection properties of punching shear strength of the slab. use a hammer drill to drill slabs and steel plate according to the specific distribution of the bolts. soon after, the surface of the slab and the holes were carefully cleaned by removing the dust and fine materials with a vacuum cleaner and also after setting the steel plate the welding technique was applied for combining elements to form one part, like as (stiffeners and steel plate) and to connect between it. figure 2. the slab column connection strengthening with steel stiffeners 4. experimental tests the experimental program of this study consisted of testing reinforced concrete square slab column connections. one of these slabs employed as a reference model (sr) and the other models employed as a strengthening model where from reinforcements. the specimens were changed by adding the steel plates and stiffeners, while the dimension of steel plate for the specimen ss1 model 100×100mm but ss2 model 200×200mm and finally for ss3 model 300×300mm. under concentrated load, the slab-column connections are tested and simply support for all four edges. the upper face of the column is leveled if there are protrusions to create the plane of the column and avoid the distribution of ununiformed stress. the static load is applied continuously until failure as shown in figure 3. the load is applied in steps at all 10 kn for the static load. the initial crack load and its position was observed. at all increasing load, remarks the crack improvement at a concrete of the specimen. the lvdt (linear variable differential transformer) was used for estimating the deflections of slabs for each step. apply three vertical lvdts, a center point for the slab’s specimen, one centered in the orthogonal direction of the one-center of the slab specimens, and one in the middle of the diagonal direction of the slab specimen, and applying the load continuously until the specimen's failure. figure 3. test setup 5. finite element modeling the abaqus / standard 2016 was used to analyze the nonlinear finite element to compare the analytical results of the finite elements with the experimental results to perform a numerical analysis of the test specimens and also to determine the efficacy and accuracy of the selected analytical finite element model for the suitability of the detected element types, modeling of material, and convergence study of a model representing the shear strengthening normal strength concrete slab column connection subjected to a static load. in this study, the flat slab was analyzing as a threedimensional model. the concrete of its length, width, and depth and also steel plate, and stiffeners are divided into brick elements (solid elements) (c3d8, 8 nodes linear brick, full integration). the element type (truss element) (t3d2, linear two-node displacement, truss element) is used for the reinforcement steel model. the truss elements are embedded in elements that are full contact model between the reinforcement and the concrete as shown in figure 4. tie was used to contact between slab surface and steel plates. convergence studies were made by reducing the element size of the reference model (sr) (100, 75, 50, 25, 20 mm). as can be seen from the convergence study, when the mesh size is reduced from (50 to 20 steel stiffener length: 100 mm width: 200 mm steel stiffener length: 200 mm width: 200 mm steel stiffener length: 300 mm width: 200 mm 202 kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206 mm), the change in displacement can be ignored. further, as the experimental results, the value of the center deflection became more accurate, so the mesh size (25 mm) was selected for all the tested slabs as shown in figure 4. polak [12] reported that the specified mesh size should be larger than the maximum size of the aggregate (20 mm in the current study). figure 4. the convergence study 6. results and discussion 6.1. failure surfaces in the control specimen (sr), the first flexural crack initiated at corners of the column on the tension surface at about (23.39%) of the ultimate load. for other slabs, the first cracks were observed on the tension surface near the corners and edges of the steel plate at loads of (22.35-18.82) % of the ultimate load. the tensile stress in concrete at the stage of loading reached the (modulus of rupture) value and the cracking began in the zone of maximum stress. with more loading, new cracks developed parallel to the diagonal axis and continued towards the slab edge. at the end of loading stages, all the slab-column specimens failed in punching shear. the test results show that the increase in the dimensions of the steel stiffeners develops first cracking load about from (40 , 45, and 48 kn) in slab-column specimens such as ss1, slab-column specimen ss2 (with dimensions 200×200 mm) and slab-column specimen ss3 (with dimensions 300×300mm). this increasing of the first crack load because the applied load is distributed on the area with relatively large rigidity. therefore, the stresses in concrete are small and as a result, the stresses of tensile in the concrete reaches the (modulus of rupture) value with large loads. this result because the steel stiffeners work as a column capital, therefore the applied load is distributed on the area with relatively large rigidity as shown in figure 5. figure 5. crack pattern of selected tested slabs 6.2. 6.2 ultimate load and deflection the deflection curve describes a state of the slab in each 10 kn increment. deflection curve was measured at the along of the length of the tested specimens (at the center of slabs, 375 mm from the center of the slab along x-axis, 530 mm diagonal direction from the center of the slab) by means of three ( lvdt) a linear variable differential transducers, and reading from this ( lvdt) was recorded to all load increment. when the improvement in the deflections at (the first stages) for the loadings was small with the development at load in an elastic behavior. when the cracks begin growing, the deflections in the slabs develop with a more active rate and continues for developing without an apparent increment in load. compared to the ultimate load of the reference slab, it is apparent that the strengthening slabs require a higher load than the reference slab to achieve the same deflection that’s mean the additional new steel plate with stiffeners was efficient for enhancing the punching strength of slab column connections. table 1 reviewed the deflection result consistent with the initial crack and the maximum loads for all slab. when the specimens tested under static load, the results observed that the ultimate punching load for (ss1, ss2, and ss3) higher than the sr (reference specimen) about (39.84%, 57% and 99.2%) respectively. when case no.1. mesh 100 mm case no.2. mesh 75 mm case no.3. mesh 50 mm case no.4. mesh 25 mm case no.5. mesh 20 mm kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206 203 the specimens (ss2 and ss3) compared with the specimen ss1 the results showed that the developed in the punching shear strength by about (12.3%, 42.5%) respectively, because increased in the parameter critical section of the steel plates and stiffeners. that’s mean the steel stiffeners were efficient in extending the critical shear perimeter, which means that further flexural reinforcement was efficient in the punching cone for increased punching shear capability. more precisely, as the number and the dimension of stiffeners increased, the maximum load was increased. figure 6 showed the relationship between the reference specimen (unstrengthen) and strengthening technique. figure 6. load-deflection curve for strengthening rc slab with steel stiffeners table 1. ultimate load of tested slabs the load-deflection curves from both exp and fea results were recorded and plotted for all specimens, as shown in figure 7 to figure 10. it can be seen that there is a good agreement between the experimental results and those obtained using the finite element program (abaqus). figure 7. load–deflection curves for sr specimen figure 8. load–deflection curves for ss1 specimen figure 9. load–deflection curves for ss2 specimen figure 10. load–deflection curves for ss3 specimen specimens first cracking load (kn) ultimate load (kn) ultimate deflection ( kn) pustif,./puref. sr 30 128 16 ---- ss1 40 179 28 1.39 ss2 45 201 23 1.57 ss3 48 255 18.92 1.99 204 kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206 7. parametric study this study helps to investigate the different parameters that do not test variables in experimental procedures, and the impact of these parameters on slab behavior, therefor this part can be divided into three main sections such as study the influence of compressive strength of concrete, study the influence of increasing the flexural reinforcement and study the influence of the circular column instead of a square column for the same volume of the square column. finite element modeling was used to study these factors. the results of the effect of the compressive strength show that the compressive strength of concrete is one of the most important variables affecting the ultimate load capacity. this is because the contribution of concrete in the compression zone after the formation of the inclined crack depends largely on the strength of the concrete. the comparison between the control specimen and the analytical result showed that the increasing the compressive strength from (50, 75, 90 mpa) would increase the ultimate load about (18.23, 28.94, and 36.4)% respectively and decrease the central deflection about (-12.6, -7.99, and -0.78) % respectively as presented in table 2 and the figure 11. also the results of the effect for increasing the flexural reinforcement on punching shear strength show that the flexural reinforcement of concrete is one of the most important variables affecting the ultimate load capacity. the comparison between the control specimen in this study and the analytical result showed that the increasing the flexural reinforcement (35%, 78%, and 100%) respectively would increase the ultimate load about (10.16, 23.1, and 31.12) % respectively and decrease the central deflection about (-18.48, -19.22, and -17.99) as shown in table 3 and figure 12. the comparison between the specimens of this study (the specimen that strengthening with steel stiffeners) and the analytical result showed that the instead of the square column with a circular column with the same volume of concrete in the specimens (ss1-1, ss2-2, and ss3-3) respectively would increase the ultimate load and the central deflection about (7.72, 5.53, and 6.55) % respectively and (5.9, 7.24, and 12.69) % respectively. figure 13 to figure 15 and figure 16 has shown the comparison of the loaddeflection curve between the three specimens and the control specimens (ss1, ss2, and ss3), the load-deflection curve showed a stiff behavior at a circular column compared with the control specimens. that’s mean the shape of the column is one of the variables affecting the ultimate load apacity table 2. comparison the effect of different values of (𝒇𝒄 ´ )on ultimate load figure 11. effect of concrete compressive strength on the behavior of slabs figure 12. effect of the flexural reinforcement on the behavior of slabs table 3. comparison the effect of increasing the flexural reinforcement on the behavior of slabs sp e c im e n compressive strength (mpa) ultimate load (pu) kn) 𝐏 𝐮 ,𝐅 𝐄 𝐀 − 𝐏 𝐮 ,𝐄 𝐱 𝐩 𝐏 𝐮 ,𝐄 𝐱 𝐩 % maximum deflection (δu) mm 𝚫 𝐮 ,𝐅 𝐄 𝐀 − 𝚫 𝐮 ,𝐄 𝐱 𝐩 𝚫 𝐮 ,𝐄 𝐱 𝐩 % ss3 25 269.3 --20.4 -- ss3-1 50 318.4 18.23 17.83 -12.6 ss3-2 75 347.24 28.94 18.77 -7.99 ss3-3 90 367.316 36.4 20.24 -0.78 sp e c im e n the increasing flexural reinforceme nt ratio ultimate load (pu) kn) 𝐏 𝐮 ,𝐅 𝐄 𝐀 − 𝐏 𝐮 ,𝐄 𝐱 𝐩 𝐏 𝐮 ,𝐄 𝐱 𝐩 % maximum deflection (δu) mm 𝚫 𝐮 ,𝐅 𝐄 𝐀 − 𝚫 𝐮 ,𝐄 𝐱 𝐩 𝚫 𝐮 ,𝐄 𝐱 𝐩 % ss3 --269.3 --20.4 -- ss3-1 35% 296.66 10.16 16.63 -18.48 ss3-2 78% 331.51 23.1 16.48 -19.22 ss3-3 100% 353.11 31.12 16.73 -17.99 kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206 205 figure 13. load–deflection curves for effect of circular column on the behavior of slabs for specimen ss1-1 specimen figure 14. load–deflection curves for effect of circular column on the behavior of slabs for specimen ss2-1 specimen figure 15. load–deflection curves for effect of circular column on the behavior of slabs for specimen ss3-1 specimen table 4. comparison the effect of circular column on the behavior of slabs with the square column 8. conclusions  the failure perimeter for the slab with (steel stiffeners) increased significantly with increasing the size and number of (steel stiffeners). this means that the size (steel stiffeners) represents the important parameters determining the crushed area (failure perimeter) around the column.  for the slab strengthening with steel stiffeners (ss1, ss2, and ss3) punching shear capacity will increase to (39.84%, 57%, and 99.2%) respectively.  the general behavior observed for load-displacement curves, mode of failure, and crack propagation of slab strengthening with (steel stiffeners) stiffer than slab column connection without strengthen.  the capacity of the punching shear strength will develop by enhancing the concrete's compressive strength from (50 to 90) mpa about (18.23, 28.94, and 36.4) % respectively concerning the specimen with (25 mpa) compressive strength.  the increase of the flexural reinforcement with the ratio of (35%, 78%, and 100%) respectively with respect to control specimen led to increasing the ultimate load about (10.16, 23.1, and 31.12) % respectively.  the capacity of punching shear showed that using circular columns instead of the square column would increase the ultimate load about (7.72, 5.53, and 6.55) % respectively concerning the specimens (ss1, ss2, and ss3). specimen the dimension of steel plates mm the height of steel plates mm p u c ir . /p u c o n t. δ u c ir . / δ u c o n t ss1 ss1-1 100×100 100 1.077 1.06 ss2 ss2-1 200×200 200 1.055 1.072 ss3 ss3-1 300×300 300 1.65 1.13 figure 16. effect of circular column on the behavior of slabs 206 kadhim and ammash /al-qadisiyah journal for engineering sciences 12 (2019) 199–206  improving the number of steel stiffeners largely enhance the capacity of punching shear which would be significant than of the control slab references [1] h. guan, y.-c.j.c.j.o.c.e. loo, failure analysis of column slab connections with stud shear reinforcement, 30(5) (2003) 934-944. [2] s.d. alexander, s.h. simmonds, shear-moment transfer in slab-column connections, (1986). [3] s. lips, m. fernández ruiz, a.j.a.s.j. muttoni, experimental investigation on punching strength and deformation capacity of shear-reinforced slabs, 109(article) (2012) 889-900. [4] r.t. mabrouk, a. bakr, h.j.a.e.j. abdalla, effect of flexural and shear reinforcement on the punching behavior of reinforced concrete flat slabs, 56(4) (2017) 591-599. [5] h.i. qassem, a.n. abbas, j.s.j.j.o.e. al-abasei, s. development, experimental study of flat plate construction with special embedded shearhead, 11(3) (2007) 95-107. [6] h. al-wetaefi, investigation on punching behavior of shearreinforced/repaired high strength concrete flat plates subjected to repeated loads, (2016). [7] g. hassanzadeh, h.j.d. sundqvist, strengthening of bridge slabs on columns. nordic concrete research [online], 1998, 27 (2003) 12. [8] widianto, rehabilitation of reinforced concrete slab-column connections for two-way shear, university of texas libraries, 2006. [9] a. ramos, v. lucio, p. regan, repair and strengthening methods of flat slabs for punching, in: international workshop on punching shear capacity of rc flat slabs, royal institute of technology, department of structural engineering, stockholm, 2000. [10] h.k. ammash, m.j. kadhim, d.s.j.j.o.e. ellk, s. development, a new punching shear equation of normal and high strength reinforced concrete flat slabs, 16(4) (2012) 47-65. [11] h.k. ammash, s.s.j.j.o.s.j.u. kadhim, effect of reinforced concrete column capital on punching shear strength of flat slab, 54(5) (2019). [12] m. polak, e. el-salakawy, n.j.s.p. hammill, shear reinforcement for concrete flat slabs, 232 (2005) 75-96. al-qadisiyah journalforengineering sciences13 (2020) 284–294 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohammed.ali@qu.edu.iq (mohammed ali mutar) https://doi.org/10.30772/qjes.v13i4.727 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. synthesis and characterization of new silicone hydrogels contact lenses based on tris-dma-aa-nvp via photo polymerization for biomedical application dhuha jawad husseina, prof.dr. mohammed ali mutara* a chemical engineering department faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 15 july 2020 received in revised form 21 august 2020 accepted 2 september 2020 keywords: contact lenses silicone hydrogel photo polymaraization copolymerization protein adsorption oxygen permeability a b s t r a c t the purpose of the present work is to designate the synthesis of innovative soft silicone hydrogel contact lenses founded on acrylic acid (aa) ,n,n dimethylacrylic amide (dma),and 1-vinyl 2pyrolidone(nvp) was polymerized via free fundamental polymerization in the existence of 1,6 hexandioldiacrylate (hdoda) as a crosslinker and 1-hydroxycyclohexyl phenyl ketone as photoinitiator. the polymerized materials were characterized fully for its use fullness as an intraocular lens by various techniques. ftir was implemented to discover the whole conversion of3-(methacryloyloxy) propyl tris (trimethylsiloxy) silane monomer into silicone hydrogels contact lens. the silicon hydrogels contact lenses were manufactured from silicon and different hydrophilic monomers, copolymerization of 3-(methacryloyloxy) propyl( tris) (trimethylsiloxy) silane with acrylic acid ,n,n-dimethylacrylamide, and n-vinylpyrrolidone(nvp) with different ratio (70,80,90)%.to explore three sequences of silicone hydrogel ingredients for their classification, water component, transmittance, mechanical feature , oxygen penetrability )dk), protein adsorption and bacterial connection as potential contact lens materials as well as tackles the connections between water kinship and optical, mechanical, oxygen permeable with biological features.the outcomes displayed that the water affinity might be moderated through the hydrophilic monomers. the equilibrium water component (ewc) rose with increasing hydrophilic monomer value. generally, the outcomes revealed that visible light transmittance inclines to increase as well as tensile mechanical features obtained in decreasing trend relying on the growing ewc. the dk worth declined firstly then was rose once the ewc was from 25 to 75%. the sum of staphylococcus aurous close to the silicone hydrogels surface of the was fell by61 to 140.this work may provide information on preparing functional silicone hydrogels for contact lenses application. ©2020university of al-qadisiyah. all rights reserved. 1. introduction the usage of non-natural materials (or “biomaterials”) inside the body being a replacement prostheses has perceived a speedy increase over the last few years ratner et al. [1]. consequently, to examine the connections between implantation, materials and body tissues has developed to be gradually of significance. once inserted, the biomaterial experiences various interactions with the host biological milieu and the “biocompatibility” of the given material relies upon numerous elements, http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 285 connected to both the host and embedded material. today, delicate contact lens is among of the biomaterials that has received great clinical exposure. contact lenses made of hydrogel are manipulated for rectifying vision for about 30 years. but, due to the oxygen penetrability of contact lenses that are conventional made of hydrogel which is based chiefly on their water content might not be up to the demands of the cornea, especially below the closed eye, stimulate the presentation of contact lenses that are made of silicone-hydrogel. the usage of contact lenses made of silicone hydrogels tamed in a novel generation of lenient contact lenses having greater oxygen penetrability than that of hydrogels that are conventional. noticing that the contact lens' surface is in straight contact with the cornea and conjunctiva, it looks clear that the surface features are significant factors to be talked because of the clinical associations that could have. contact lenses made of silicone-hydrogel constituents show diverse surface features on account of the combination of diverse composition that are chemical as well as surface treatment [2], [3]. surface treatments are done for the sake of gaining wettable surfaces [4],[5]. putting contact lenses is perhaps the greatest omnipresent usage of a medical hydrogel in our society. a hydrogel is a cross-linked polymer containing hydrophilic units which normally dissolve in water. however, crosslinking prevents the polymer from dissolving. recently, silicone hydrogel (sihy) contact lenses are developed to be the mainstream product in the market of contact lens due to their superior oxygen penetrability, that is 3 to 6 times greater than conventional poly-hema grounded hydrogel lenses efron et al. [6]. since oxygen is able to transfer easily through the silicone units in sihy lenses, the oxygen permeability is enhanced significantly as well as is not restricted by the water component as conventional hydrogel lenses are. the improvement allows a high level of comfort as well as developed corneal healthiness throughout prolonged wear (even over the night wear) by sustaining a adequate level of oxygen attentiveness at the ocular surface. while sihy lens are highly successful, the adsorption of tear components to contact lenses remains a main risk of contact lens putting which could cause user discomfort and reduced visual acuity heynen et al. [7], and eventually leads to discontinuation of lens putting [8], [9]. consequently, contact lenses as well as lens-care products are frequently engineered to decrease deposition and improve wear comfort. unfortunately, the advantageous hydrophobic segments in sihy lenses also reduce surface wettability, which is highly correlated with wear comfort. irritation and dry eye syndrome are induced when tear films are unable to spread across the hydrophobic lens surfaces. thus, the lens material itself is a predominate factor to the level of comfort and the tendency to sorbs tear components. for example the surfaces of lotrafilcon b lenses are plasma coated a continuous ultra-thin hydrophilic layer which improves the wettability read et al. [10], and which also lowers the lipid deposition significantly. while using hydrogel lenses to deliver therapeutic drugs to eyes is not a new idea, little research has been done in controlled release of comfort agents or lubricants molecules from lenses. a screening study was performed in this thesis research to select possible agents to be loaded into several sihy macromere formulations, which opens the door to produce lenses that can deliver an additional level of comfort over many hours. the present work is pointing to explore the outcome of those monomers on a contact lens that is silicone-dependent from tris, dma, nvp and aa in relation to oxygen and water absorbability, protein approval, and wettability. hence, the resultant tris-aa,tris-dma-aa as well as tris-dma-nvp-aa hydrogels are characterized by ftir spectrum, equilibrium water component, oxygen penetrability, optical permeability, contact angle, mechanical properties, the adsorption process of protein, and cytotoxicity. 2. experimental methods 2.1. preparation of silicone hydrogels hydrogels that are made of silicone were underwent the process of polymerization from tris, dma, aa, and nvp monomers with different ratio (10%,20%,30%) by polymerization process that is free-radical in the existence of cross-linking agent hdoda as well as photo motivator pi184, as listed in table 1. the reaction mix were emptied from gas using nitrogen for 30 min to eliminate the oxygen. then the mix was moved in a dim milieu at room heat for 30min. afterward, pouring into polypropylene molds, the mix was healed below 365 nm uv light for 40 min. then, demolding process took place, the lens material was refined by soaking in 50% ethanol for 24 h at 50 °c to eliminate the monomers that are un-reacted and photo motivator. after that, the lens was engrossed in refined water for 12 h at 50 °c to wash out the ethanol. finally, the lens was conserved in pbs (ph 7.4) at chamber heat. for all constructions,the percentages of hdoda and pi184 were 0.625 wt % as well as 0.4 wt %, respectively tran et al. [11]. figure 1. the process of making contact lenses [12]. abbreviations cls soft contact lens scl silicone contact lens ewc equilibrium of water component dk dkare's units of oxygen penetrability ws weight of lens after immersion wd weight of lens before immersion cat concentration during time kl reaction rate constant t time of adsorption ca0 initial concentration mps mega pascal hdoda 1,6 hexandioldiacrylate nvp 1-vinyl 2pyrolidone aa acrylic acid dma n,n dimethyl acrylic amide tris silicone (si) 3-(methacryloyloxy) propyltris (trimethylsiloxy) silane. ph measure of how acidic/basic in water photo initiator 1-hydroxycyclohexyl phenyl ketone (pi184) pbs phosphate buffer saline eth ethanol n2 nitrogen dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 286 table 1. formulations of silicone hydrogel through copolymerization of tris, dma, aa, nvp. sam ple feed monomer tr is si time irradia tion ew c% dk cont act angle º modu lus (mpa ) d m a a a n vp a1 0 4. 5 0 0.5 2 58 92 92.0 85 0.001 37 a2 0 4 0 1 3 52 103 115. 312 0.001 57 a3 0 3. 5 0 1.5 11 32 61 131. 5 0.001 b1 2.2 5 2. 25 0 0.5 2 60 120 61.3 27 0.001 55 b2 2 2 0 1 3 55 140 41.5 12 0.001 8 b3 1.7 5 1. 75 0 1.5 7 25.6 64. 14 113. 703 0.002 c1 1.5 1. 5 1.5 0.5 4.30 75 84 75.6 0.000 58 c2 1.3 3 1. 33 1.3 3 1 3 63 86 101. 124 0.003 9 2.2. equilibrium water content dried hydrogel pieces were implemented to control the water content, the water content was regulated by submerging the hydrogel (0.1gm) in 100 ml of distill water 24 hrs through a lengthy period of time. excess water was eliminated from surface by blotting with lens-cleaning tissue just before measurements. the equilibrium water component (ewc) in distillated water was regulated through the weight of water's ratio in the hydrogel to the entire hydrogel weight at equilibrium of hydration.ewc was measured through the usage the ensuing equation. 𝐸𝑊𝐶 = 𝑊𝑠 − 𝑊𝑑 𝑊𝑠 × 100% (1) where ws as well as wd correspond to the weight of the swollen example as well as dried sample, correspondingly [13]. 2.3. oxygen permeability oxygen penetrability is fundamentally controlled through ewc in hydrogels that are conventional. such happens as oxygen is capable of passing over the water more than over the substance itself. oxygen penetrability is designated as the dk, where d is the diffusivity of the substance as well as k is the solubility of the substance. the connection amid ewc as well as oxygen penetrability was established to be (morgan & efron equation). dk=1.67e 0.0397ewc (2) where ‘ewc’ is equilibrium water component of the substance. the dkare's units of identified being barrer: 𝐷𝐾(𝑏𝑎𝑟𝑟𝑒𝑟) = 10−11(𝑐𝑚2×𝑚𝑙𝑂2) 𝑠𝑒𝑐×𝑚𝑙×𝑚𝑚𝐻𝑔 (3)[14] 2.4 optical transparency the membrane's transparency was studied with the use of uv-visible spectrophotometer, sample were made through cutting to a slight piece (1 cm × 1 cm) after by solvent evaporation method as well as engrossed in refined water for 24 hrs to approaching equilibrium of swelling. the calculations were done from 200 to 700 nm wavelength at chamber heat tran et al. [11]. 2.5 contact angle the estimation of the outward wettability of the lens made of silicone hydrogel substance depended on the test of contact angle. calculations showed that with the use of a contact angle goniometer (dsa 100, krüss gmbh, hamburg, germany) at room heat, the contact angle assessment was the average of five measurements tran et al. [15]. 2.6 mechanical features after swelling in refined water, the specimens were sample 2cm × 3cm rectangular form. the specimens that are dry were obtained by placing them into an oven at 40ºc in one day. the tensile features of the examples were calculated at a crosshead speed of medium, in agreement with astm d1708 standard, using a tensile tester (transact, motorized force test stand ,esm, mark -10 , eden prairie, mn, usa). kim et al. [16] 2.7 protein deposition the membranes of the hydrogel were engrossed in solution of phosphate buffer (pbs, ph 7.4) 5ml for 24 hrs. then, drenching the membranes of hydrogel in sole solution of protein of bovine serum albumin for 3 hrs at 37 °c the usual temperature of the human eye's surface, the attentiveness of solution of the protein was 0.5mg/ml. later, a membranes' adsorption of the of hydrogel were located mildly in to pbs for 5 second to eliminate extra solution adhering to the membranes of the hydrogel. the membranes were after that put in a tube made of glass having 1wt% aqueous sodium dodecyl sulfate's solution (sds) to eliminate the adsorbed proteins found on the membranes. the sum of the adsorbed proteins on the surface of the membrane was measured from the attentiveness of proteins into the solution of sds with the use of bradford evaluates reagent kit at the end, protein deposition of all specimens was calculated by a uv-vis spectrophotometer tran et al. [11]. 2.8 evaluation of bacterial adhesion the lenses are made of different types of mixtures consisting of a mixture of silicon and hydrogel. the lenses are kept within a saline solution. the tasters were washed with 100 ml of sterile saline three times tasters were saved in 3 ml of pbs solution. adhesion examination was performed by the method of editing the adherent bacteria by ultrasound, where the lenses were exposed to bacterial isolates by dilution 10-4and 10respectively and for each isolation for 30 minutes and 60 minutes, then the lenses were put in sterile vials having 1 ml of pbs solution and then the super waves were shown at a rate of 75 khz placed in a water bath with a depth of 1 cm at a temperature of 30ºc for a period of (15-15) minutes after which the vials were transferred to the vortex vibrator for 1-2 minutes .then withdraw about 100 ml of the solution containing the free bacteria for the dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 287 samples and spread on the dishes containers on tsa incubated the dishes for 24 hours at 37°c and the cell numbers were calculated with a value of cfu / mm2 alkhozai et al. [17]. 3. results and discussion 3.1.1. synthesis and characterization of (si-co-aa) tris is saleable monomer made of silicone to sustain great oxygen penetrability in contact lens, whereas (aa)was preferred due to its hydrophilicity to afford abundant greater water component. in the start, only tris was copolymerized with (aa). the silicone hydrogels were to underwent polymerization from tris and (aa) monomers in the existence of cross-linking mediator 1-6 hexanedioldiacrylat and photo initiator, 1hydroxycyclohexyl phenyl ketone, using different percentages (10%, 20%, 30%).the combination was moved in a dim milieu at room heat for 30 min. once being dispensed in polypropylene shapes, the combination was healed below 365 nm uv light for 2 minutes at 10%, 3 minutes at 20% and 11 minutes at 30% of si. nevertheless, the synthesis procedure of macromere was fairly made complex. in this paper tris was used as portion of silicone monomers. when tris was combined in the polymers, the compatibility of monomers that are hydrophilic might be heightened. those manufactured hydrogels made of silicone display capacity to develop the transparency. figure 2. copolymerization and crosslinking of hdoda with (si-coaa) 3.1.2. ftir spectrum the ftir spectrum of (si-co-aa),the hydrogel found in silicone constituents could perceive a stout group of –si–o3stretching at 636 cm 1,two feeble group of –si–(ch3)3extending at 683 as well as 735 cm -1 , a feeble band of –ch3 distortion at 1406 cm -1and a robust group of – ch3extending at 2890 cm-1;which designates absorption group at 34003420cm-1because of (-oh str. band in polymer),2940cm-1,2830cm-1to (ch str. aliphatic backbone polymer), 1758cm-1 (c=ostr., ester band),1688cm-1to (c=o str. carboxyl band),1152cm-1 to (c-o-c str.) as well as 1085 cm-1to (-c-o of c-oh str.).moreover, distinctive bands at about 900 cm−1 as well as 3100 cm−1conforming to the vinyl groups of monomers vanished completely, that showed nonexistence of unreacted monomers [18], [19] . figure 3. ftirspectrum of hydrogel of(si-co-aa) figure 4. preparation of si-co-aa 3.1.3. synthesis and characterization of (si-co-aa-codma) tris is a marketable monomer made of silicone to preserve great oxygen penetrability in contact lens, whereas (dma) was selected due to its hydrophilicity to afford plentiful greater water component . in the start, only tris was copolymerized with (aa).the hydrogels made of silicone were to underwent polymerization from tris and (dma)&( aa) monomers in the existence of cross-linking mediator 1-6 hexanedioldiacrylate and photo initiator, 1-hydroxycyclohexyl phenyl ketone, using different percentages (10%, 20%,30%).the combination was moved in a dim milieu at room heat for 30 min. when being dispensed in polypropylene shapes, the combination was healed below 365 nm uv light for 2 minutes at 10% , 3minutes at 20%, 7 minutes 30% of si. though, the synthesis procedure of macromere was fairly sophisticated. in this paper was used tris as portion of monomers made of silicone. when tris was assimilated into the polymers, the compatibility of monomers that are hydrophilic might become improved. those synthesized hydrogels made of silicone display ability to develop the transparency. figure 5. copolymerization and crosslinking of hdoda with si-coaa-co-dma. dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 288 3.1.4. ftir spectrum the ftir spectrum of (si-co-aa-co-dma), the hydrogel founded by silicone constituents might perceive a robust band of –si–o3 extending at 636 cm-1, two feeble group of –si–(ch3)3 extending at 683 and 735 cm -1 , a feeble band of –ch3 distortion at 1406 cm -1 as well as a robust band of – ch3 extending at 2890 cm-1; which designates absorption band; 3433 cm1to (-oh str.), 3402 cm-1 to(-cooh str.),2947 cm-1,2869cm-1 to (c-h str. of backbone of polymer),1710cm-1 to (c=o str. ,carboxyl band ),1072 cm1to (-c-o of c-oh str.), the amide i group happens in the area of 16201670 cm-1for n’n-dialkyl replaced amides rogers [20].the amide i group at 1629 cm-1is credited mostly to the c=o extending way by certain aids from the c-n extending way. the polarized group at 1086 cm-1 have been given here to the symmetric stretching ways of the n(ch3)2 group. once dma underwent polymerization in the hydrogels made of silicone, two new groups at 1629 as well as 1086 cm-1performed, that paralleled to the c=o and n(ch3)2 of the monomers that are acrylamide, correspondingly. the concentration of 1629 cm-1 and 1086 cm-1risethroughgrowing the sums of dma. the outcomes provide stout sign of the presence of dma in the copolymers that are silicone hydrogel. furthermore, distinctive groups at about 900 cm−1 and 3100 cm−1stable. to the vinyl groups of monomers vanished totally, that designated nonexistence of unreacted monomers [18], [19]. figure 6. ftirspectrum of hydrogel of(si-co-aa-co-dma) figure 7. preparation of si-co-aa-co-dma 3.1.5. synthesis and characterization of (si-co-aa-codma-co-nvp) tris is profitable monomer made of silicone to preserve great oxygen permeability in contact lens, whereas (dma)&(aa) were selected for its hydrophilic aspect to offer abundant greater water component. in the start, merely tris underwent copolymerization with (nvp). the silicone hydrogels underwent polymerization from tris and (dma),(aa)& (nvp) monomers in the existence of cross-linking mediator 1-6 hexanedioldiacrylatand photo initiator, 1-hydroxycyclohexyl phenyl ketone, using different percentages (10%, 20%,30%). the combination was moved in a dim milieu at room heat for 30 min. once being dispensed into polypropylene shapes, the mix was healed below 365 nm uv light for 4.30 minutes at 10%, 3 minutes at 20% of si. nevertheless, the synthesis method of macromere was fairly difficult. in this study tris was employed as part of silicone monomers. once tris as well as bis was assimilated in the polymers, the compatibility of monomers that are hydrophilic might be improved. those manufactured silicone hydrogels display potential to develop the transparency. figure 8. copolymerization and crosslinking of hdoda with si-coaa-co-dma-co-nvp. 3.1.6. ftir spectrum the ftir spectrum of (si-co-aa-co-dma-co-nvp), the hydrogel founded by silicone constituents might perceive a tough band of –si– o3extending at 636 cm -1, two feeble group of –si–(ch3)3extending at 683 as well as 735 cm-1 , a feeble group of –ch3distortion at 1406 cm-1 as well as a tough band of –ch3 extending at 2890 cm-1;which indicates absorption band ; 3433 cm-1to (-oh str.), 3402 cm-1 to (-cooh str.), 2947 cm-1,2869cm-1 to (c-h str. of backbone of polymer), 1710cm-1 to (c=o str. ,carboxyl band), 1072 cm-1to (-c-o of c-oh str.),1688 cm-1 to (c=o of the nvp),1450cm-1,1427 cm-1 and 1265 cm-1 were allocated to the distinctive vibration of the pyrolidone ring, and the top at 1164 cm-1 to (co-c str.), the amide i group happens in the area of 1620-1670 cm-1for n’ndialkyl replaced amides rogers [20]. the amide i group at 1629 cm-1 is credited chiefly to the c=o extending way by certain participation from the c-n extending way. the polarized at 1band 086 cm-1 have been allocated here to the symmetric extending ways of the n(ch3)2 group. when dma was polymerized into the hydrogels made of silicone, two novel groups at 1629 and 1086 cm-1seemed, which matched to the c=o and n(ch3)2 of the monomers that are acrylamide, correspondingly. the concentration of 1629 cm-1 as well as 1086 cm-1rise with rising the sums of dma. the obtained results offer strong sign of the presence of dma in the hydrogel made of silicone copolymers. moreover, typical groups at around 900 cm−1 and 3100 cm−1 analogous. to the vinyl bands of monomers vanished entirely, that designated nonexistence of unreacted monomers [18], [19] . dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 289 figure 9. ftirspectrum of hydrogel of (si-co-aa-co-dma-convp) figure 10. preparation of si-co-aa-co-dma-co-nvp 3.2. equilibrium water content the water component of a hydrogel material is associated with the number of hydrophilic sites in the polymer. the hydrogel's hydrophilic nature of materials is derived from the ability of hydrophilic group (negatively charged) to share an electron with a molecule of water and inversely related to the number of crosslink mccarey et al. [21]. the water content of different ratios of aa are signifies the water content to time for diverse percentage of acrylic acid. hydrophilic monomer which has been too effectively employed in contact lens made of hydrogels is acrylic acid (aa).after put to a lenient lens of polymer construction, it consequence in a lenient lens with ionized bands (negatively charged) inside the matrix of the polymer, letting the lens to absorb extra water. the greater the sum of (aa), the greater the ewc of the subsequent polymer or lens, that's allowing oxygen permeability to rise considerably. once si/aa lenses are made they want to be ionized (i.e.; the atom of the hydrogen in the carboxyl band is eliminated ). the alteration of the carboxyl group (co2h) to the further hydrophilic ionized form (the anion that is carboxylate, co2-) lead to increasing the water content. nevertheless, this negative charge leads to the carboxylate ions to prevent each other frequently denoted to as ‘growing the network'. this has the outcome of letting the network to take in extra water. if the polymer was not ionized, then the substance might get an unexpanded network musgrave et al. [22]. to rise the water component of contact lenses through copolymerization of polar monomers such as acrylic acid aa, dma, and (nvp) are polymerized with silicon into silicon hydrogels, which increases the water content due to the hydrophilic of the co monomers that manipulated to rise the ability of the hydrogels to take up more water. the ewc of silicone hydrogel with rising dma content rose from 25.6% to 75%. the alike outcome was stated in zhang’s study omali et al. [23]. greater component of monomer of zwitterionic sulfobetaine in hydrogel shown a greater ewc since the unit of sulfobetaine might cooperate with water by both electrostatic forces and hydrogen ties, that delivered a tougher water attraction. as predicted , the amide band of dma offers extra hydrogen bonding sites for water; consequently, a greater kin ship for water was created in the silicone hydrogels by a more dma component.the results show that higher hydrophilic monomers gives higher water content in the hydrogel contact lenses. figure 11. ewc% for different ratios of monomers. 3.3. oxygen permeability generally , the silicone constituent has an exceedingly great ability to permeate to oxygen greater than dk standards. as predictable, the dk of hydrogel made from silicone grew higher along with the rise of silicone monomer. conventional contact lenses depend on water to transmit oxygen over the lens.dk restrictions differs from traditional hydrogels, where oxygen can be transported. over the silicon constituent in the silicone hydrogel substances, which leads to a great distance increased oxygen permeability. investigate dk as well as water content of diverse hydrogel made of silicone lenses on the market as well as discovered an opposite relationship amid dk as well as water content likewise, several previous works showed opposite relationship between dk as well as ewc due to silicon hydrogel lenses water is the restricting element in the permeability of oxygen chien et al. [24]. the dk of silicone was barrers, as well as the value grew higher to barrers once the component of monomers made of silicone rose to 30%. subsequently, we modified the mingling ratio of (nvp, aa and dma) monomers that are hydrophilic to inspect the connection amid hydrophilic monomers content as well as dk fig. 8. the dk worth of the silicone hydrogel without hydrophilic monomers wear around barrers. as the rise of hydrophilic monomers component from (70 to 90)%, the dk worth decreased faintly as well as approached a lowest value of barrers at the 70% hydrophilic monomers component. the dk worth reserved about barrers once the hydrogel made of silicone with hydrophilic monomers component in a range from 82 to 142. later, the dk values started to slowly increase by the rise of hydrophilic monomers component. once the hydrophilic monomers component surpassed 80%, the dk worth rose severely as well as come close to barrers at the hydrophilic monomers content of 80 %. dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 290 figure 12. the correlation between dk and ewc. 3.4. transmittance the transparency of these hydrogels made from silicone was calculated by scanning through a uv/v is spectrophotometer into a wavelength variety around (400 as 700) nm. it was shown that the influence of structure and water component on transparency as transparency faintly dropped with the rise of silicone component . the hydrogels made of silicone with 10 to 30 % monomer silicone displayed the transmission ability from (89.5 to 93)%.then, equivalent sums of monomers made of silicone were employed with changing relative sums of dma, aa, and nvp. the influence of the ado of ratio of hydrophilic monomers on the transparency of the hydrogels was examined. the outcome displays that transparency rise with rising hydrophilic monomers component. the transparency for lenses with 70%, 80% and 90% from hydrophilic monomers with silicon monomer correspondingly. when the composition of the silicon hydrogel contact lenses were more than 80% from hydrophilic monomers, the lens revealed the transmittance over 98%. we additionally planned the worth of transparency in contradiction of the ewc as well as originate there was a positive connection amid grew ewc as well as noticeable light transmittance. those outcomes showed that manufactured hydrogels made of silicone are transparent adequate for ophthalmic uses. moreover, the transparency of constituents might be moderated through the conformations of the hydrogels made of silicone. light transmission ability is the calculation of the contact lenses' transparency. parting stage because of the unsuccessful collaboration of silicone as well as hydrogel bands might lead to opaque lenses and limit light transmissibility. fig. 13 displays that the light transmittance of all the hydrogel lenses varied about (96 to 97)%, signifying that whole of the samples are appropriate for contact lenses, which requires the light transmittance to become higher than 90%. figure 13. light transmittance of hydrated modified silicone hydrogel examples. figure 14. value of transparency as a function of the percentage of ewc in silicone hydrogels. figure 15. the value of transparency as functions of silicone monomer. 3.5 contact angle as a significant element affecting, the surface's wettability aspect of the lenses was assessed by the contact angle of a drop of water onto the surface which is hard. comparable to envisaging dk, could too be manipulated to expect the contact angle from ewc. surface's wettability is a significant to contact lens that affecting putting comfort and reducing happenings of an eye that is dry. the surface wettability aspect of lens made from hydrogel is assessed through calculating the contact angle. nevertheless, this process is further sensitive to ecological circumstances due to the reorientation of hydrophobic field, particularly silicone chains in the network of the silicone hydrogel. principally, with the innate flexible construction, si-o bonds in silicone chains can rotate away from the surface of lens matrix if it discloses to moist environment. on the contrary, the hydrophobic practical band will become major on the surface of the lens when opened to dry milieu. briefly, the reasons for poor surface wettability are the original hydrophobic substance as well as migration of silicone bands in hydrogel made of silicone contact lens. contact angle as well as ewc are connected to the hydrogel's hydrophilicity. hydrophobic tris dropped the hydrophilicity of the hydrogel, as well as henceforth dropped the wettability of the surface of lens. moreover, the monomer that is hydrophobic (tris) is subtle to ecological circumstances due to its reorientation aspect [25], [26]. with the integrals duple construction, silicon-oxygen ties in tris monomers would rotate forth the monomer of the lens monomer in a dry milieu french et al. [27]. consequently, tris is the monomer which affects the contact angle dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 291 worth of hydrogel made of silicone lens substantial in relation to a preceding study zhao et al. [28]. tris component, the contact angle of 10 wt% was greater than 20 wt%, as well as 30 wt %. furthermore, contact angle rose intensely in the presence of nvp, aa, and dma for the similar tris component. this indicates that hydrophilic monomers could rise the wettability for polymers of hydrogel made of silicone. in the literature, nvp was capable of continue worthy wettability of the surface through 4–6 h of putting on, whereas dma cause low wettability for the alike wearing time lai et al. [29]. to sum up, in this paper, nearly all contact angles of hydrated lenses were below than 80which is analogous to that of other profitable contact lenses like lotrafilcon a(air optix night& day), as well as balafilcon a (pure vision) maldonado-codina et al. [26]. figure 16. the correlation between ewc and contact angle for (tris-dma-nvp-aa). 3.6. mechanical properties the young’s moduli were considered from the linear visco-elastic variety as well as shortened in table 1. the existence of monomers made of silicone in hydrogels displays the greater young’s modulus and the lesser elongation at break. in the instance of 30% monomers content made of silicone, it’s young’s modulus was extreme (mpa(. generally, lenient contact lenses by moduli vacillating from to mpa are cooler to content might manage mechanical features. for modulate the water component, we put a monomer that is hydrophilic, aa, nvp and dma, in the constructions to moderate the mechanical features of the hydrogels made of silicone. the existence of higher hydrophilic monomer might decrease young’s modulus an dim prove presence. young’s modulus fall together with rising hydrophilic monomer component. figure 17. the correlation between the modulus and ewc for (trisdma-nvp-aa). figure 18. the correlation between the modulus silicone monomer. 3.7 protein adsorption protein is an essential element which relays on the transport as well as metabolism of cellular membranes, hypothetically displaying in antimicrobial or infection of the corneal of the eye [30] . biomaterials that is ophthalmic for contact lenses must not adsorb ingredients of tear film like lipid as well as protein, due to the protein deposition could be painful, raise bacterial cell interaction to the corneal epithelium ,and associated with massive conjunctivitis that are papillary silva et al. [31]. bradford assay, originally is one of the popular methods to determine protein concentration. the procedure of adsorption protein from an aqueous solution on a solid surface is characteristically labeled in three stages. at the beginning, transportability of the protein got from the solution up to the surface that is solid befalls. this is followed by supplement of the protein to the surface, as well as lastly the protein construction endures a conformational alteration afterward adsorption. dijt et al. [32] luensmann [33] explored the influence of ionic charge on the approval of bsa, their outcomes displayed that rising the negative charge of the material such as aa make less the deposition of negatively charged bsa. proteins adsorbed in greater amounts with rising neutral nvp concentrations; nvp affects protein adsorption to a degree, the amount of protein adsorbed rises with the rise in the nvp content of the hydrogels. the unique bipolar aspect of the lactam moiety in the nvp component outcomes in the poly(si-co-nvp) hydrogels being both partly negatively charged at the carbonyl group and partly positively charged at the nitrogen end closest to the comparatively hydrophobic chain backbone. therefore, as a result of the electrostatic attraction amid the positively charged nitrogen group and the negatively charged of protein, depending on the negatively charged bsa protein in connotation with the positive nitrogen present in nvp. nevertheless, this explanation is depending on the supposition that the electrostatic interaction happens between individual charge groups in nvp and protein molecules luensmann [33]. for bsa, once the tris component rose from (10 to 30)%, the protein's adsorption of reduced from (2.543 to 0.193)µg/cm2.the deposition of protein of contact lens is also affected through extra aspects like ph of milieu, dimension of protein, charge of protein, lens material, water component , coarseness of lens surface, as well as substantial aspects [34], [35]. in earlier study, protein adsorption was straight forward comparative to the rise of hydrophobic ingredients and tris component, that ensued in lessening water component [36], [37]. nevertheless, yet other dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 292 research designates which rising bsa adsorption was affected by loading hydrophilic constituents, specifically nvp [31], [38], [39]. figure 19. the influence of contact angle on the adsorption of albumin, a mono monomer, b di monomer tri monomer. 3.7.1finding the reaction order for protein albumin adsorption on contact lenses the degree of reaction was tested from (zero, first, second order) and after plotting the results, it was found it to be second order as follows: zero order : [𝐶𝐴𝑡] = −𝑘𝑡 + [𝐶𝐴0](4)the curve not liner first order: 𝐿𝑛[𝐶𝐴𝑡] = −𝑘𝑡 + 𝑙𝑛[𝐶𝐴0] (5) second order : 1 [𝐶𝐴𝑡] = 𝑘𝑡 + 1 [𝐶𝐴0] (6) figure 20. effect of order reaction on the adsorption of albumin ;a :mono monomer, b :di monomer, c: tri monomer. figure 21. the correlation between the wave length and adsorbent; a: mono monomer, b :di monomer, c: tri monomer. 3.8 evaluation of bacterial adhesion corneal bacterial inflammation (transparent tissue by the front of the eye), caused by germs, is a disease that threatens vision, and can appear in children and adults. most germs do not have access to a complete and healthy cornea, but when the cornea is exposed, for example, after eye damage or a foreign object entering it, the germs can enter into it and lead to inflammation. the common bacteria that lead to bacterial infection of the cornea are staphylococcus, which includes the pseudomonas in the present research, an assay on pseudomonas bacteria was performed. on ophthalmic features, cellular performance is noteworthy responsible for the biocompatibility of cells lin et al. [40]. a test that is cytotoxicity was led to detect the alteration of cellular shape through the addition of the take out medium of lens that is made of hydrogel to a cell culture. the contact lenses' surface is ready to adhesion that is microbial pathogens that cause ocular contaminations stapleton et al. [41]. staphylococcus aurous is one of the types found recurrently in human eyes, were too noticed on contact lenses of persons xiao et al. [42]. hence, staphylococcus aurous was used by way of a bacterial example to test the adhesion that is bacterial of the lens ingredients. the average sum of bacteria add-on the hydrogels made of silicone were around 104cfu/ml. moreover, bacterial connection for numerous mixing ratios of, aa, nvp and dma monomers that are hydrophilic in hydrogels made of silicone were examined. the addition of monomers that are hydrophilic other than 35% pointedly reduced the adhesion of bacteria to around 103 cfu/ml. after the lenses have been exposed to bacteria (staphylococcus) and incubated for 24 hours, we notice that the highest adhesion rate for bacteria on the lenses is after one and a half to two hours. dilution there are different types of it, nevertheless decamitigation was used. this was conducted by taking 1ml of bacterial growth at a certain concentration and dilute it in a ratio of 1 to 10. the process was repeated and each time we reduce it, it becomes ten to the negative one and the twelfth to the negative to the second negative, and so on the more bacteria the concentration, the more cells are attached the third dilution, for example, bacteria b more than the sixth thus sticking more. as for the acceptable limits for the presence of bacteria on the lens . it is assumed to be a parameter, but of course it is present .here the type of bacteria plays a role. there are dangerous bacteria as soon as they exist we refuse to use the lens. of course there is no specific number. here comes the role of the control group and we compare with it where we compared the results with a search alkhozai [17]. generally, a surface which coarser is disposed to further bacterial adhesion because inadequacies on the dhuha jawad hussein , mohammed ali mutar /al-qadisiyah journalfor engineering sciences 13 (2020) 284–294 293 surface region where contamination bonds are probable to form tam [43]. the encouraging correlation was too stated by giraldez et al. [44] once the further hydrophobic silicone contact lenses display larger vulnerability to adhesion that is staphylococcus epidermidis to the lenient contact lenses that are conventional giraldez et al. [45]. the obtained results agree with the previous work, it was proposed that the hydrophilicity of the lens surface is among shaping elements for adhesion that is bacterial. figure 22. the value of adhered cells, a: mono monomer, b: di monomer, c: tri monomer. 4. conclusion in this paper, three sequences of hydrogels made of silicone were made through being underwent copolymerizing two monomers that are siliconcontaining tris with three monomers that are hydrophilic aa,nvp as well as dma. the used method is efficient to develop the transparency of silicone hydrogels. the ewc, soft transmittance, mechanical features, dk, as well as bacterial attach ability of got silicone hydrogels were calculated, as well as their associations were argued in details. the outcomes displayed which the ewc value rose through the rise of monomers that are hydrophilic. with rising ewc, noticeable light transmittance inclines to rise, nonetheless flexible mechanical features offered in a decreasing trend. the outcomes also displayed that the dk worth dropped at the beginning as well as later rose once the ewc was from (25.6 to 75)%. the deterioration point of ewc was around 42.5%. for biological aspect, the sum of the bacteria approached towards the hydrogels that are made of silicone falls by rising hydrophilic monomer. agreeing to general experimental outcomes, the best percentage of silicone obtained in contact lenses is 20%, the silicon hydrogels(si-co-aa), (si-co-aa-co-dma), and (si-co-aa-co-nvp-co-dma) are greatly appropriate for the use in contact lenses due to the improved mechanical features as well as little adhesion that is bacterial. in our study, we used optical polymerization in the manufacture of contact lenses instead of thermal, as it gave very fast results in minutes instead of long hours. we also used hdoda, which was not previously used in the manufacture of contact lenses, as it gave excellent results compared to the rest of the crosslinking agents. in addition, the production of new lenses with high oxygen permeability and suitable for human use and drug loading interaction lens. reference [1] b. d. ratner, a. s. hoffman, f. j. schoen, and j. e. lemons, biomaterials science: an introduction to materials in medicine. elsevier, 2004. 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[45] m. j. giraldez et al., “contact lens hydrophobicity and roughness effects on bacterial adhesion,” optom. vis. sci., vol. 87, no. 6, pp. e426--e431, 2010. article al-qadisiyah journal for engineering sciences 12 (2019) 098–104 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7825381859. e-mail address: mohanad.shallal@qu.edu.iq ( muhaned a.shallal) https://doi.org/10.30772/qjes.v12i2.595 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. experimental study on self-compacted concrete-filled steel tubular (cfst) truss girders marwa m.thejeela and muhaned a.shallala* a faculty of engineering –university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 21 june 2019 received in revised form 07 july 2019 accepted 08 july 2019 keywords: cfst truss girder self-compacted concrete warren-vertical truss design equation a b s t a c t this paper studies the performance of steel tube truss girders filled with self-compacting concrete. four concrete-filled steel tubular (cfst) truss girders specimens were tested. the first novelty in this research was using square tubes to manufacture truss girder. the main parameters were the bottom chord concrete compressive strength and reinforcing steel bar employment in the bottom chord (second novelty). one bar with a nominal diameter 16mm was used to reinforce the concrete in the bottom chord while keeping the concrete in the top chord without reinforcement. this paper shows the load-displacement curves at the midspan, deflections along the span, peak loads, flexural strength, and failure shapes of the tested specimens. the design equation was used to predict the flexural strength of cfst truss specimens. results show that the flexural strength was increased with the increase in the concrete strength from 29.23mpa to 48.41mpa by about 4.5% and was increased by about 10.27% when using reinforcing the concrete in the bottom chord. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction concrete-filled steel tubular cfst truss girder is one of the most important inventions in civil engineering; generally, consist of concrete filled steel tube chords and hollow steel tube braces. the presence of concrete can delay or prevent local buckling of the steel tube. meanwhile, the steel tube provides sufficient confinement for the concrete and therefore can increase the strength, stiffness, and ductility for tension, compression members, and then for joints. the infill concrete also provides a good resistant to seismic force by their good durability under cyclic loading. on the other hand, the steel tube works as formwork for casting concrete, which saving labor costs and construction cost and time [1-3]. cfst trusses have been extensively used in different types of structures. for instance, they have been used as girders in bridges, for example, in ganhaizi bridge, china, as shown in fig. 1. they have also been used as girders in the roof system. the cfst truss girder investigations have been started since 2000 by zhang et al. [4]. since then, various experimentally and theoretically studies have been carried to investigate the behaviour of cfst truss girders. chen et al. [5], conducted three experimental work for pratt type truss girders. the first specimen hollow steel tube was used in chords and braces. for the second specimen, the top chord was filled with concrete while the bottom chord and the braces were hollow. for the third specimen, the top and bottom chords were filled with concrete, while the braces were hollow. the tests indicated that the presence of infill-concrete in chords increased the strength and stiffness of cfst truss girders. huang et al. [6] studied the effect of truss type on the behaviour of cfst truss girder. three specimens were tested in this research, the first was warren-vertical truss type (which has vertical braces along with diagonal braces), the second was pratt truss, and the third was warren truss. the tests indicated that the warren-vertical http://qu.edu.iq/ mailto:mohanad.shallal@qu.edu.iq https://doi.org/10.30772/qjes.v00i0 marwa m.thejeel and muhaned a.shallalb /al-qadisiyah journal for engineering sciences 12 (2019) 098–104 99 figure 1: ganhaizi bridge, china. cfst truss girder had better performance, followed by the pratt truss and then the warren truss. xu et al. [7] tested the behaviour of eight curved cfst trusses. the tested specimens included four curved cfst trusses, two straight cfst trusses, and two curved hollow steel tube trusses. han et al. [8] showed the development and applications of cfst members. on the comparison between cfst members with steel and reinforced concrete rc members, the load carrying capacity of cfst member was higher than the summation of a load of steel and rc members. han et al. [9] tested ten cfst trusses girders (warren truss). they studied the effect of shear span to depth ratio, infill concrete, slab concrete and the angle between chords and diagonal braces. these studies denoted that the strength and stiffness of cfst trusses significantly increased when compared to hollow steel tube trusses and the cfst trusses had two types of failure modes; tensile fracture of bottom chord and shear failure. zhou et al. [10] studied the performance of cfst truss girders warren truss type. four circular section specimens were tested; hollow steel section chords (ch), concrete-filled top chord (ct), concretefilled bottom chord (cb) and concrete-filled bottom and top cord (ca). the research indicated that the best load carrying capacity obtained from specimen ca and was 180kn, while the maximum load obtained from specimens ch, cb, and ct were 85, 92.2, and 145kn, respectively. in the last years, the behaviour of the cfst truss girder was investigated by wenjin et al. in 2012 [11]. welded joints of circular hollow steel and cfst truss girder were studied. the presence of core concrete in the top and bottom chords increased the joint rigidity and the strength of the whole truss. the governing failure mode was the punching shear failure. in 2017, huang et al. [12] studied the behaviour of pre-stressed cfst truss girder. high strength strands were used to get on pre-stressed cfst truss girder. five specimens were tested to study the performance of shear span to depth ratio and pre-stress level. the results indicated that the strength and stiffness of the pre-stress cfst truss girders were increased by increasing the ratios of shear span to depth and pre-stress level. the failure mode was a tensile fracture of the bottom chord when the shear span to depth ratios increased. on the other hand, the joint shear failure was the dominant failure mode if the latter ratios decreased. in 2018, huang et al. [13] investigated the behaviour of warren-vertical truss girders experimentally and numerically using finite element analyses (fea). the test results indicated that the cfst had two failure modes, tensile fracture of the bottom chord (flexural dominated) and shear failure in the joint (shear dominated). cfst trusses must be designed as a flexural dominated, so the author put some point (i) the compression strength concrete in a top chord not less than 1.1% from that in the bottom chord, (ii) shear span to depth ratio ≥ 4.8, (iii) brace to chord ratio ≥ 0.8 the truss load carrying capacity mainly depends on the strength of the bottom chord (in the case the sections of the top and bottom chords were the same), this is due to the lack of concrete effect in the tensile area compared to the compression zone. therefore, many researchers have tried to strengthen the tensile properties. studies have shown that the increase of the compressive strength will improve the properties of the tensile members, but affect the ductility of the truss. so in this study, the strengthening the bottom chord by adding a conventional steel reinforcement bar embedded in the concrete core in the bottom chord was investigated. the self-compacting concrete was employed in this study for being suitable in such types of structures. 2. experimental work four cfst truss girders (warren-vertical truss) were tested. the test parameters were; the bottom chord reinforcement and concrete compressive strength, as shown in table 1. the designation used in table 1 to describe each specimen: the first part (r0) indicates that there is no reinforcing steel bar embedded in the bottom chord, (r1) denotes the bottom chord reinforced by one steel bar with diameter 16mm, the second part (t) indicates the concrete grade at top chord, the third part (b) indicates the grade of concrete at the bottom chord. the concrete grade describes the concrete cube compression strength in mpa at 28 days. the dimensions of all specimens were kept same: the length was 2660 mm, truss height was 500 mm, chord width (b) was 100mm, the wall thickness of the chord (t) was 3.8mm, brace width (b𝑏) was 80mm, thickness wall of brace (t𝑏) was 2.8mm and the angle between the chord and inclined braces was 54° as shown in fig. 2.. the width and wall thickness for the first and nomenclature 𝐴𝑠𝑐 cross-section area of the steel and concrete 𝑀𝑒𝑥𝑝. flexural strength obtained from experiments 𝐴𝑠 cross-section area of the steel 𝑀𝑒𝑞. flexural strength obtained from equation 1 𝐴𝑐 cross-section area of the infill concrete 𝑃𝑢 peak load obtained from experiments b width of chords c compressive strength of the top chord t chord wall thickness t tensile strength of the bottom chord 𝐵𝑏 width of braces 𝑓𝑦 steel yield stress 𝑡𝑏 brace wall thickness 𝑓𝑢 steel ultimate stress h truss height 𝑓𝑐𝑢 concrete cube compressive strength h truss height centroidal distance between top and bottom chords £ confinement factor 𝑀𝑢 flexural strength α steel ratio, α = 𝐴𝑠/𝐴𝑐 100 marwa m.thejeel and muhaned a.shallalb /al-qadisiyah journal for engineering sciences 12 (2019) 098–104 last braces were increased to 100mm and 3.8mm, respectively, because these braces carried extra forces from supports so the diameter and wall thickness increased to avoid the local buckling. after specimen fabrication, the specimens were placed vertically and filled with self consolidation concrete. after that the specimens stored in the laboratory for 28 days for testing as shown in fig. 3.. the steel properties measured according to astm 370-05a[14] as shown in table 2. the type of concrete used in this study was self-compacting concrete (scc), and the mix proportions of scc were given in table 3. the fresh concrete tests were presented in table 4, while the average cube strength (fcu) were 29.23 mpa and 48.41mpa, respectively. the concrete properties measured according to european guidelines [15]. table 1. specimen details. .specimen id. 𝒇𝒄𝒖 (mpa) h (mm) b (mm) t (mm) 𝐁𝒃 (mm) 𝐭𝒃 (mm) top chord bottom chord r0t50b30 50 30 500 100 3.8 80 2.8 r0t50b50 50 50 500 100 3.8 80 2.8 r1t50b30 50 30 500 100 3.8 80 2.8 r1t50b50 50 50 500 100 3.8 80 2.8 3. test results 3.1. ultimate load and mid-span deflection all specimens were tested using a 3-point load configuration. the load was applied by a hydraulic jack machine with a capacity of 1000 kn and measured by a load cell. two lateral supports were provided on each side to supply stability to the specimen. three linear variable displacement transducers (lvdts) were used to measure the vertical deflection, as shown in fig. 4. (a)elevation view of the truss girder section a-a (b)without reinforcement (c)with reinforcement figure 2: specimens details. (a)position the chords (b)complete welding (c)specimens paint (d)cast concrete figure 3: fabrication and cast of the test specimens. table 2, the steel properties. member 𝒇𝒚 (mpa) 𝒇𝒖 (mpa) top and bottom chord 335 371.24 brace 390 437.59 steel bar 16mm 480 545.54 table 3, concrete mix proportions. mix type c30 c50 cement (kg/𝑚3) 300 450 sand (kg/𝑚3) 670 670 gravel (kg/𝑚3) 730 730 limestone powder (kg/𝑚3) 110 90 sp % 1 1.5 water (kg/𝑚3) 210 189 w/c ratio 0.7 0.42 𝑓𝑐𝑢 at 28-day 29.23 48.41 table 4, fresh concrete test results. test id. c30 c50 specification slump flow (mm) 760 730 ( 600 – 800) mm t50 slump (sec) 3 3.5 ( 2 – 5) sec l box 0.9 0.85 ( 0.8 – 1) v funnel (sec) 9.4 10.1 ( 8 – 12) sec marwa m.thejeel and muhaned a.shallalb /al-qadisiyah journal for engineering sciences 12 (2019) 098–104 101 figure 4: test set up. fig. 5. shows the load-deflection curves at mid-span for the test specimens. the behaviour of test specimens is similar, and is summarized as follows; the load mid-span deflection remained linear when the applied load was less than 0.75pu (pu is the peak load). after that, the steel tube in the bottom chord gained hardening, and the top chord yielded at approximately 0.9pu. the peak load (pu) and flexural strength (mu) gained from tests is summarized in table 5. the results were divided into two parts; the concrete compressive effect and steel reinforcement presence in the bottom chord. the results indicated that the concrete grade has a little effect on the strength. flexural strength of specimen r0t50b50 was increased by about 4.55% as compared to specimen r0t50b30, and the strength of specimen r1t50b50 as compared to r1t50b30 was increased by about 10.34%. the effect of the presence of steel reinforcement was more effective with high compressive strength. steel works to increase the ductility for such specimens. the flexural strength of specimens r1t50b30 and r1t50b50 as compared to specimens r0t50b30 and r0t50b50 were increased by about 4.92% and 10.27% respectively, fig. 6. shows the variation of the peak load due to the effect of the concrete compressive strength and the effect of the reinforced concrete in the bottom chord. in the plastic stage, the deformities became high and affected the joints where one of the joints failed in the welding area completely due to tension loads, while some of these joints suffered from buckling due to compression loads. some of the failure modes are shown in fig. 7. the use of steel bars embedded in the bottom chord showed an improvement in load resistance as indicated, but this improvement in the results could have been obtained by increasing the wall thickness of the steel tube and may have a better effect when using bigger sections. table 5, peak load and flexural strength. specimen name 𝑷𝒖(kn) 𝑴𝒖(kn.m)* r0t50b30 252.295 410.236 r0t50b50 264.88 430.71 r1t50b30 264.72 430.44 r1t50b50 292.09 474.945 *calculated (𝑀𝑢 = 𝑃𝐿/4) (a)concrete effect (b)reinforcement effect figure 5: load mid-span deflection. (a)concrete effect. (b)reinforcement effect figure 6: peak load variation ratio. 102 marwa m.thejeel and muhaned a.shallalb /al-qadisiyah journal for engineering sciences 12 (2019) 098–104 3.2. the deflections profile deflections profile is shown in fig. 8. . due to symmetry the deflections in the second half of the truss equal to the deflections in the first half. these deflections compared with half-sine curves represented as a dashed line. it is clear that when the load was less than 0.75pu the half sine curves and the deflections along the span of cfst specimens are almost the same. when the applied load exceeded the 0.75pu, half sine curves didn’t coincide with those obtained from the tests except at mid-span, because that the steel tube yielding and fracture result in the deflections to focus at the middle. these results are similar to those found by xu et al.[7] and huang et al.[13]. (a)joint failure. (b) joint failure. (c)weld fracture. (d)braces buckling. figure 7: modes of failure. (a)r0t50b30 (b)r0t50b50 (c)r1t50b30 (d)r1t50b50 figure 8: deflection along the span at different load levels. 4. predicted design equation cfst truss girders have three possible failure shapes, local buckling of the top chord, tensile fracture of the bottom chord, and joint failure. cfst trusses girders must be designed as flexural dominated (tensile fracture of the bottom chord) because they had better ductility due to the good tensile behaviour of cfst members. meanwhile, cfst truss girders designed as a joint failure had less ductility. the proposed flexural strength determined from the following equation[9]. m = min.( c , t ) * d (1) where d is the centroid distance between the bottom and top chords, c compressive strength of top chord, and t tensile strength of bottom chord. the compressive strength of the top chord (c) and the tensile strength of the bottom chord (t) can be predicted by the following equations. these equations were suggested by han et al. [16, 17]. c = ∑(1.14 + 1.02£) 𝑓𝑐𝑢 𝐴𝑠𝑐 (2) t = ∑(1.1 – 0.4α) 𝑓𝑦 𝐴𝑠 (3) where £ = 𝑓𝑦 𝐴𝑠/𝑓𝑐𝑢 𝐴𝑐 is the confinement factor, 𝑓𝑐𝑢 is the concrete strength, 𝐴𝑠𝑐 is the cross section area of steel and concrete, α = 𝐴𝑠/𝐴𝑐 is the steel ratio, 𝐴𝑠 is the cross section area of the steel tube bottom chord, 𝐴𝑐 is the cross section area of the concrete, and 𝑓𝑦 is the steel tube bottom chord yield strength. the summation symbol (∑) was proposed by the author, which is used when there is more than one type of steel section. the predicted design equations were used to propose the flexural strength of the four specimens tested in this paper and compared to previous research. fig. 9. shows the comparison results, the horizontal and vertical axis represents the flexural strength obtained from the tests (𝑀𝑒𝑥𝑝.) and from han equation (𝑀𝑒𝑞.1), respectively. table 6 shows the test specimen flexural strength obtained from the experimental test and han equation and compared with other research results. han equation considered equations that give acceptable results to estimate the flexural strength of cfst member within 20%. however, there are some observations on these equations; (i) han proposed these equations when tested column subjected to direct axial tension, so the strain was uniform on the section, meanwhile, the strain in the cfst truss girders was linear and that caused the defect especially when the cross-section of the chords was large, (ii) han equations did not take into account the presence of any additional section within the original section, as in this search adding a steel bar in the concrete of the bottom chord. marwa m.thejeel and muhaned a.shallalb /al-qadisiyah journal for engineering sciences 12 (2019) 098–104 103 5. conclusion this research studied the performance of cfst truss girders. four cfst truss girders were tested experimentally. the test parameters were the concrete grade of the bottom chord and embedded steel reinforced bar of the bottom chord. the tests indicate that the increase of concrete compressive strength increases the strength of the cfst trusses. using the reinforcement in the bottom chord of specimens, r1t50b30 and r1t50b50 increased the flexural strength by about 4.92% and 10.27%, respectively. proposed design equations were used to predict the flexural strength of the cfst truss girders which give acceptable results within 20%, but this equation must be modified to take into consideration the existence of additional sections within the original section for example the presence of steel reinforcement. figure 9: comparison of the flexural strength obtained from the test and eq. 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[12] w. huang, z. lai, b. chen, p. yao, experimental behavior and analysis of prestressed concrete-filled steel tube (cft) truss girders, engineering structures, 152 (2017) 607-618. [13] w. huang, z. lai, b. chen, z. xie, a.h. varma, concrete-filled steel tube 104 marwa m.thejeel and muhaned a.shallalb /al-qadisiyah journal for engineering sciences 12 (2019) 098–104 (cft) truss girders: experimental tests, analysis, and design, engineering structures, 156 (2018) 118-129. [14] a.d. 370-05a, "test methods and definitions for mechanical testing of steel products", , american society for testing and material, (2001 annual book of astm standards,). [15] the european guidelines for self-compacting concrete specification, production and use, (may 2005). [16] l.-h. han, g.-h. yao, x.-l. zhao, tests and calculations for hollow structural steel (hss) stub columns filled with self-consolidating concrete (scc), journal of constructional steel research, 61(9) (2005) 1241-1269. [17] l.-h. han, s.-h. he, f.-y. liao, performance and calculations of concrete filled steel tubes (cfst) under axial tension, journal of constructional steel research, 67(11) (2011) 1699-1709. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 574 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. dr. ali raad hassan, university of technology, mechanical engineering department, baghdad. e-mail: aliraad972@yahoo.com khalid mohsin ali, university of technology, mechanical engineering department, baghdad. e-mail: khalid2771991@gmail.com received on 27 september 2017 accepted on 13 december 2017 published on 20 february 2018 doi: 10.30772/qjes.v10i4.506 abstract: this paper presents the dynamic response related to varying in indispensable parameters of pulley-belt system, a manufactured pulleybelt system has been built and experimental results have been obtained and analyzed accurately which reveal the effects of these parameters on indicated system. manufactured system assembled from heavy steel structure, variable speed dc motor, speed measurement tool (tachometer), two shafts of 25 mm diameter, four pillow block ball bearings, v-belts and pulleys with different diameters (10, 15, 20, 25) cm. the fabricated system presents mechanical characteristics likes serial changing in rotational speed (500 to 2000) rpm, diameters ratios (1 to 2.5) and center distance (27 to 120) cm. accelerometer adxl335 (3-axis) mounted on bearing brackets of drive and driven shafts and connected to arduino type mega 2560 (microcontroller) which sending the data of vibration to the laptop in order to display it in sigview software as a time and frequency domain band by fft (fast fourier transform). results showed the effects of change the values of rotational speed, center distance, and diameters ratios on vibration response of pulley-belt system. keywords: dynamic response, fft, rotational speed, diameters ratios, center distance. introduction machines are very essential in our lives and it simplified the people’s works. now we use machine to the maximum extent in our daily activities, machines are becoming more complex, faster, intricate, and delicate and production process that are interlinked and automated. the efficiency of machines depends on many factors like raw materials, accuracy, enduringness, intelligent design…etc. pulley-belt machinery is a basic part in any industry, which need to appropriate design and calculate pulley’s diameters, belt length and radius ratio before manufacturing. in this paper an experimental investigation of the dynamic response of pulley-belt system were studied using vibration monitoring analysis the effects of pulley center distance, r.p.m, effects of rotational speed, center distance and diameter ratios on the dynamic response of pulley-belt system depends on vibration analysis file:///c:/users/khalid%201991/appdata/local/temp/aliraad972@yahoo.com mailto:khalid2771991@gmail.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 575 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. and diameter ratio which is the terrific tool to get the earliest warning that is beginning to occur in early stages of machines failure occurring may end up if we do not anything about earliest failures, in a sense, enables us to look inside the machine and see exactly what’s going on. in a simply vibration analysis process need to sensor for vibration sensing (accelerometer) , data acquisition to plotting recode data and a software to show the signals thus examining , analyzing and diagnosing faults and defects in machine parts. a lot of experimental researches has specialized in vibration monitoring, the most important of them such as: hu ding [1] investigation periodic responses of a pulley belt system with one-way clutch under inertia excitation, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. moreover, numerical results demonstrate that the two excitations interact on the steady-state response, as well as the damping effect of the one-way clutch. indrajit chowdhury [2] presented dynamic response of machine foundations considering soil damping and embedment paper proposes a method based on which a number of such deficiencies as cited above can be circumvented. chitresh nayak et al [3] presented design and development of machine fault simulator (mfs) for fault diagnosis. this paper show how to industry and construction of machine contains most parts that get damaged and vibrate over time in plurality machines like motor .gregor c epona et al [4] presented introduction of damping into the flexible multi body belt-drive model, good agreement between the numerical result and the experimentally obtained data was found. finally, the applicability of the belt-drive model was presented in a comparison with the pinned–pinned beam model. chyuan-jau shieh [5] studied the effect of angular speed on behavior of a v-belt drive system. this paper shows the effect of rotate speed on the 3d friction contact surface behavior between v-belt st13mm and pulley abdulshakoor et al. [6] used vibration analysis for faults in v-belt 13mm, three faults are used side-cut-out, side-cut-in and loose. mouleeswaran and moorthy [7] monitored vibration for defect diagnosis on a machine tool (comprehensive case study). s.ojha et al. [8] investigation the performance monitoring of vibration in belt conveyor system, this paper presents the vibration related faults diagnosis and maintenance of belt conveyor system. s. r. algule et al [9] presented experimental study of unbalance in shaft rotor system using vibration signature analysis. puneet bansal et al [10] deals with monitoring and analysis of vibration signal in turning machine with one type of cutting tool and sample (mild steel and brass). b. kiran kumar et al [11] presented determination of unbalance in rotating machine using vibration signature analysis. pravesh and akhilesh [12] focused on fault diagnosis of ball bearing using time domain analysis and fast fourier transformation. arko djajadi et al [13] presented monitoring vibration of a model of rotating machine. the case study was a rotate shaft with balance and unbalance by add and reduce mass of balance. sakshi kokil et al [14] studied detection of fault in rolling element bearing using condition of monitoring by experimental approach. dimitris et al [15] practically studied maintenance topics of mechanical drivers and faults diagnosis of machine elements. this paper presents vibration monitoring using as a design technique, results were taken from many experiments at different dimensions and values of center distance, radius ratio and speed, at constant tension 30n, and v13 belt type. 1. experimantal setup and vibration measurment machine was manufactured with personal experience by researchers, it consisted of heavy structure steel frame, steel pulleys, dc motor variable speed, shafts, pillow bearings ,tachometer and tools for precision measurements as shown in figure 1. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 576 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. vibration sensors adxl335 (3axis accelerometer) [16] with sensitivity of 300 mv/g, this sensor can read a range of 0.5 hz to 1600 hz for the x and y axes, and a range of 0.5 hz to 550 hz for the z axis output, sensors mounted geometrically on bearing brackets of drive and driven shafts .y-direction of sensor will be with axil direction of shaft .x and z will be radial on shaft horizontal and vertical respectively as show in figure2 sensors connected to arduino type mega which have cpu 16 mhz sending the data of vibration after calibration process to the laptop to display it in software model (sigview) as a time and frequency domain band by fft (fast fourier transform). to know the magnitudes of rotate speeds need to rpm gauge (tachometer dt-2234a) photo type with reflective tape on rotate parts as shown above. initial tension should be at a constant value of 30n in each cases, this value determined as installation tension (optimal) by the manufacturing company (super star belts), also this magnitude investigated by tensile test device and pidansys, data of tensioned belt deals as hyper-elastic material by moony-revilin model. different pulleys and belts differesizes initial tension measurement laser pulley alignment laptop steel structure safe box of dc motor speed drive & arduino dc motor reflective tape of tachometers tachometer figure 1: details of system parts. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 577 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: two sensors adxl335 geometrically positions. 2. vibrations analysis vibration can be used to detect and diagnose problems on rotating equipment ranging from electric motors to large crushing machines used for mining and processing. because each part is in a case of motion has an individual frequency. fft has important features to show for each part its frequency, also frequency of faults which are unavoidable due to the errors and accuracy in manufacturing or may temporarily develop in the system due to the operating conditions. the most encounter faults existing in the pulley belt system described in the following table [17]. having in mind that the fundamental frequency is shaft revolution in rpm 1x. table 1: common faults in belt-pulley systems. symptom frequency comments unbalance 1x unbalance mass, misalignment belt misalignment 2x,3x coupling looseness 1 3x-10x radial structural looseness looseness 2 0.5x,1.5x,2.5x,3.5x excessive bearing unsteady resonance 1x belt or structure resonance bearings frequencies ball pass frequency outer race ball pass frequency inner race ball spin frequency fundamental train frequency cage worn or loose belt 1x-4x of belt frequency faults in belt , al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 578 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. to recognize healthy conditions from bad or faulty conditions of operating machines, time domain waveform will be as shown in figure 3. faulty conditions waveform will give incomprehensible signal and more peaks in fft at different frequencies. while at good conditions wave form will be consistent and sinusoidal often. while at a good conditions waveform will be consistent, sinusoidal often, and low and low number of peaks in fft will appear. figure 3: experimental results of: good condition (a1 time domain waveform, a2 frequency domain), faulty condition (b1 time domain waveform, b2 frequency domain). m / 𝑠 2 𝑚 / 𝑠 2 𝑚 / 𝑠 2 𝑚 / 𝑠 2 a1 a2 b1 b2 sec sec hz hz al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 579 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 3. vibration measurement test three cases of change parameters each one has four results which will be existed the dynamic response of change each parameter separately, the following table illustrates the methodology.where: (c) the center distance between drive and driven shafts, (i) radius ratio, (n) rotating speed of motor in rpm, (ti) initial belt tension. table 2: methodology of obtaining results. cases change parameter constant parameters at ti =30 n a b c d 1 rotating speed rpm c = 37cm i = 1:1 500 1000 1500 2000 2 center distance cm n=1500rpm i=1:1 37 47 57 67 3 reduction ratio c=37cm n= 1500rpm 1:1 1:1.5 1:2 1:2.5 it is necessary to check belt-resonance state which in fft shows high peaks at 1x in the radial directions. 18n initial tension, 1500 rpm (25hz), 10x10 cm pulleys diameters, and center distance 37 cm. figure below of stroboscope camera picture shows belt resonance state. resonance state depends on belt initial tension, center distance and rotating speed. figure 4: stroboscope camera picture shows belt resonance. 4. results and discussions case 1:running speed changes : figures (5),(6),(7) show response due to rpm increases at (x,y,z) direction respectively, meanwhile the results show general increase in any peak of each founded fault as rpm increase, and it gave high increase in horizontal directions (x1, x2). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 580 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. f ig u re 5 : rp m c h a n g e , x 1 a n d x 2 . 5 0 0 r p m 1 0 0 0 r p m 1 5 0 0 r p m x 1 x 2 2 .5 x 4 x 3 .2 x m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 581 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. f ig u re 6 : rp m c h a n g e , y 1 a n d y 2 . y 2 y 1 5 0 0 r p m 1 0 0 0 r p m 1 5 0 0 r p m m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 6 x 6 x 3 x 2 x 2 x 1 .3 x 2 .8 x 5 x 2 .7 x 2 0 0 0 r p m al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 582 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 5 0 0 r p m 1 0 0 0 r p m 1 5 0 0 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 f ig u re 7 : rp m c h a n g e , z 1 a n d z 2 . z 1 z 2 3 .3 x 6 x 2 .7 x 3 x 1 .1 x 4 .8 x 1 .3 x 2 0 0 0 r p m al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 583 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. case 2:center distance changes: figures (7), (8), (9), shows increasing in vibration due to increase length of belt (center distance), and there is signification change in fft peaks due the change center distance cases with center distance values: (37, 47, 57, 67) cm, this behavior happened while no resonance state done in the conditions of (1500 rpm, pulleys 10x10 cm, initial tension 30n) at above center distance. f ig u re 8 : c e n te r d is ta n c e c h a n g e , x 1 a n d x 2 . x 2 x 1 3 7 c m 4 7 c m m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s2 1 x 1 x 3 .2 x 6 7 c m al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 584 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. y 1 3 7 c m 4 7 c m 5 7 c m 1 x 1 x 2 x 3 .6 x 3 .6 x f ig u re 9 : c e n te r d is ta n c e c h a n g e , y 1 a n d y 2 . y 2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 585 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. z 1 m/s 2 m/s 2 m/s 2 m/s 2 z 2 3 7 c m 4 7 c m 5 7 c m f ig u re 1 0 : c e n te r d is ta n c e c h a n g e , z 1 a n d z 2 . 1 x 3 .4 x m/s 2 m/s 2 m/s 2 m/s 2 al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 586 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. case 3:reduce ratio changes: where drive pulley diameter value is 10 cm and driven pulleys diameters are (10, 15, 20, 25) cm, and drive speed of 1500 rpm (25 hz) with driven pulleys speed of (1500, 1000, 750, 600) rpm which means (25, 16.66, 12.5, 10) hz; results presented no signification change in (x1, y1, z1) directions as figures (11), (12), (13), shown. but there is general decrease in acceleration peaks at (x2, y2, z2) due to rpm reduce and diameter increase (diameter ratios increase (1, 1.5, 2, 2.5). f ig u re 1 1 : re d u c e r a ti o c h a n g e , x 1 a n d x 2 . x 1 x 2 1 :1 1 :1 .5 1 :2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 3 .3 x al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 587 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. f ig u re 1 2 : re d u c e r a ti o c h a n g e , y 1 a n d y 2 . y 1 y 2 1 :1 1 :1 .5 1 :2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 3 x 6 .4 x al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 588 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. f ig u re 1 3 : re d u c e r a ti o c h a n g e , z 1 a n d z 2 . z 2 z 1 1 :1 1 :1 .5 1 :2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 3 .3 x 2 .8 x 1 x al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 589 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. conclusion by analyzing the results graphs it may be concluded that the intensity of vibration changed in some cases and no intelligible changes in other cases as parameters manipulate, accordingly some results show significant changes at some or all axis while some results not affected. figures (5),(6),(7) of case 1, show response due to rpm increases, the (acceleration-frequency) graph in figure (5) present the (accelerationfrequency) graphs from sensor 1 at x1 direction, the affected region started from (0 to 180) hz on the horizontal axis of graph (frequency axis) where some peaks of acceleration appears with maximum values (0.6, 2.1, 4, 6) m/s 2 corresponding to (500, 1000, 1500, 2000) rpm respectively. nearly, the obtained results from sensor 2 at x2 direction are same. figure (6) show from y1 direction the affected region starting from (0 to 80) hz of frequency axis producing some peaks of acceleration with maximum values about (0.45, 1.4, 1.8, 2.4) m/s 2 corresponding to (500, 1000, 1500, 2000)rpm respectively. while for the same region at the obtained graphs from sensor 2 at y2 direction for the same sequence of rpm the maximum values of peaks of acceleration were (0.8, 1.2, 2.4, 2.8) m/s 2 respectively. figure (7) show from sensor 1 in z1 direction the effected region started from (0 to 160) hz in the frequency axis, produce some peaks of acceleration with maximum values about (0.24, 0.64, 1.8, 2.1) m/s 2 corresponding to the same sequence rpm, while for the same region at graphs obtained from sensor 2 in z2 direction maximum peaks values where about (0.64, 1, 1.2, 1.8) m/s 2 . from the above results and the behavior of vibration noticed in fft graphs, it can be considering that the increasing in rpm cause increases in the number of acceleration peaks and in the value of these peaks. in the higher speeds small difference occurs between the two sensors readings because of the direction of rotation and sensor 2 location on driven pulley (in the end of belt). in case 2, figures (8,9 and 10) , shows noticeable response due to the increase in length of belt (center distance), from sensor 1 the affected region starts from (0 to 100) hz on the frequency axis which produce some peaks of acceleration with the maximum values of (2, 2.3, 2.8, 3.1) m/s 2 in x1 direction, (2.3, 3.2, 3.6, 5.2) m/s 2 in y1 direction, and (0.45, 0.85, 1.2, 1.95) in z1 direction corresponding to selected center distance values of (37, 47, 57, 67) cm. the resulted graphs from sensor 2 for same affected region were (1.8, 2.1, 2.4, 2.7) m/s 2 in x2 direction, (2.1, 4.8, 4.85, 5.4) m/s 2 in y2 direction, and (1.2, 1.4, 1.5, 1.8) m/s 2 corresponding to selected center distance values of (37, 47, 57, 67) cm. hence, from the above fft graphs results it can be considering that the increase in the center distance between the two pulleys (belt length) will cause increases in the acceleration peaks values (vibration) which agree with the theoretical concepts of pulley-belt systems. in case 3, drive pulley diameter value fixed on 10 cm and driven pulleys diameters values have a sequence increase as (10, 15, 20, 25) cm, with drive speed of 1500 rpm (25 hz), while driven pulleys speed were (1500, 1000, 750, 600) rpm which means (25, 16.66, 12.5, 10) hz due to the increase in diameter ratio values. figures (11,12 and 13) shows noticeable response due to the increase in driven pulley diameter values (diameter ratio), from sensor 1 (located on drive pulley bearing) the affected region in fft graphs starts from (0 to 150) hz on the frequency axis which produce some peaks of acceleration with the maximum values of (4, 4.8, 8, 6) m/s 2 in x1 direction, (1.5, 3, 2.6, 3.2) m/s 2 in y1 direction, and (1.9, 0.9, 0.8, 0.65) in z1 direction corresponding to selected diameter ratio values of (1:1, 1:1.5, 1:2, 1:2.5). the resulted fft graphs from sensor 2 (located on driven pulley bearing) for same affected region were (1.5, 1, 0.8, 0.6) m/s 2 in x2 direction, (2.5, 4.5, 2.1, 2.1) m/s 2 in y2 direction, and (1.3, 1.6, 0.8, 0.5) m/s 2 in z2 direction, corresponding to same selected diameter ratio values. from above results it can be notice at diameter ratio of (1:1) that the both sensors gave a close values nearly. but during the sequence increase in driven pulley diameter values (diameter ratio) an decreases in acceleration peaks values occurs, this lead to consider that the increase in diameter ratio will cause a decrease in vibration especially on driven pulley. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 590 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. resonance fault should be investigated during system operation by stroboscope camera as figure (4) shown, then the critical values of speed ratio and center distance which cause the resonance case can be avoided. if there is any faults related to pulleys, belts, shafts and bearings it will be noticed clearly by the fft spectrum above figures, then it will be detected by analyzing this indicated figure in order to make correction by maintenance processes. reference 1. hu ding, “periodic responses of a pulley belt system with one-way clutch under inertia excitation” journal of sound and vibration. pp. 308-328, 353 (2015). 2. chowdhury, “dynamic response of machine foundations considering soil damping and embedment” petrofac int.ltd. september 2011. 3. chitresh nayak, vimal kumar pathak, sagar kumar. prashant athnekar, “design and development of machine fault simulator (mfs) for fault diagnosis”, international journal of recent advances in mechanical engineering (ijmech) vol.4, no.4, pp.77-84, november 2015. 4. gregor cepon, lionelmanin, mihaboltezara, “introduction of damping into the flexible multibody beltdrive model: a numerical and experimental investigation “, journal of sound and vibration 324, pp.283–296, february 2009. 5. chyuan-jau shieh, wen-hwa chen, ” effect of angular speed on behavior of a v-belt drive system”, international journal of mechanical sciences 44, pp.1879–1892, june 2002. 6. abdulrahman abdulshakoor al bulushi, g.r. rameshkumar and m. lokesha, ”fault diagnosis in belts using time and frequency based signal processing techniques” international journal of recent advances in mechanical engineering,vol.6,no.11,pp.11-20, november 2015. 7. mouleeswaran senthilkumar, moorthy vikram and bhaskaran pradeep, ” vibration monitoring for defect diagnosis on a machine tool: a comprehensive case study”, international journal of acoustics and vibration, vol. 20, no. 1, pp.4-9, february 2015. 8. s.ojha, d. sarangi, b.k. pal, b.b. biswal, ” performance monitoring of vibration in belt conveyor system”, journal of engineering research and applications, vol. 4, issue 7(version 6), pp.22-31, july 2014. 9. s. r. algule, d. p. hujare, ” experimental study of unbalance in shaft rotor system using vibration signature analysis”, international journal of emerging engineering research and technology, vol.3, issue 4, pp 124-130, april 2015. 10. puneet bansal, i. s. rajay vedaraj, ” monitoring and analysis of vibration signal in machine tool structures”, international journal of engineering development and research, vol. 2, issue 2, pp.2310-1317, 2014. 11. b. kiran kumar, g. diwakar, dr. m. r. s. satynarayana, ” determination of unbalance in rotating machine using vibration signature analysis”, international journal of modern engineering research, vol.2, issue.5, pp-3415-3421, sep-oct. 2012. 12. pravesh durkhure, akhilesh lodwal, ” fault diagnosis of ball bearing using time domain analysis and fast fourier transformation”, international journal of engineering sciences and research technology, pp.711715,july 2014. 13. arko djajadi, arsi azavi, rusman rusyadi, erikson sinaga, ”monitoring vibration of amodel of rotating machine”, journal of mechatronics, electrical power, and vehicular technology,vol. 02, no 1, pp 51-56, 2011. 14. sakshi kokil, prof. s. y. gajjal, assist. prof. m. m. shah, prof. s. d. kokil, ” international journal of engineering research & technology, vol. 3 issue 8, pp.859-866, august 2014. 15. dimitris c. tsantiotis, theodore n. costopoulos, and ioannis s. zotos, ” maintenance of mechanical drivers and fault diagnosis of machine elements”, 2nd international conference “from scientific computing to computational engineering”, 2nd ic-scce athens, 5-8 july, 2006. 16. adxl335 data sheet, https://www.sparkfun.com/datasheets/components/smd/adxl335.pdf. 17. c. scheffer phd, meng, saimeche, “practical machinery vibration analysis and predictive maintenance” chapter 5, p.89, first published 2004. https://www.sparkfun.com/datasheets/components/smd/adxl335.pdf article al-qadisiyah journal for engineering sciences 14 (2021) 092–098 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: apk34551@gmail.com (mohammed s. kadhim) https://doi.org/10.30772/qjes.v14i2.748 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. enhancement of airfoil performance by rotating cylinder mohammed sadeq kadhima*, dhafer a. hamzaha department of mechanical engineering, the university of al-qadisiyah, ad-diwaniyah, iraq. a r t i c l e i n f o article history: received 18 april 2021 received in revised form 12 june 2021 accepted 13 june 2021 keywords: airfoil enhancement rotating cylinder performance naca6409 a b s t r a c t this study used a naca 6409 smooth wing section. its performance is compared to an enhanced design incorporating a revolving cylinder on the upper airfoil surface. the boundary conditions for the present work were reynolds (105), and the attack angles were (0,2,4,6,8,10,12,14,16). a turbulence model was developed (sst k-), one of the aerodynamics models. this model is well-suited for sensing flow near a wall. the cylinder was evaluated at three positions (25,50,75) percent of the chord's length. the results indicated that position (25 percent c) was optimal, as it resulted in a 24.45 percent increase in lift coefficient at the angle of attack (12). and when the results were compared to those of other studies, they revealed a significant agreement. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction there is a growing interest in flow control, especially aerodynamics, and there are plans to increase lift and reduce airfoil resistance. because of the adhesive effects, the wings suffer flow separation at high angles of attack, leading to a significant lift force loss and increased drag. as a result, the efforts of academics have been intensified to research and investigation the latest methods and techniques in controlling flow separation. h. park et al.[1] presented a passive technical analysis for separating flows. the tabs were put on the airfoil's back edge, both upper and lower. an investigation was conducted experimentally by varying (height, width) of the tabs and their spacing, the reynolds numbers (2*104, 4*104, and 8*104). the results indicated that the base pressure increased (drag was reduced) for all selected reynolds numbers and that the base pressure increased by (30 %). [2, 3] presented a study of the technique of vortex generators using different reynolds numbers. , relied on a basic investigation, that when vortices are generated in a thicker boundary layer, the vortices transfer the highmomentum fluid to the boundary layer. this makes it thinner and has a higher resistance to reverse pressure gradient. the results showed an improvement in the airfoil performance. w.w. huebsch et. at. [4],they view flow control as flow instability due to the viscous sublayer. the use of synthesis vortices to produce increased mixing, and absorption to obtain the correct synthesis (or a combination of the above). when the dynamic amplitude is comparable to the boundary layer height, the boundary layer state changes completely the results of this work demonstrate indicate that dynamic roughness can be employed effectively to control leading-edge separation flow in the reynolds number range studied. the dynamic roughness is defined according to the scale of the approaching lamellar layer is entered the start of separation. the boundary layer changed earlier than the natural one. [5-10] conducted numerical and experimental investigations, or a combination of the two, on airfoils with various forms and dimples (external, internal, tennis ball shape, and teardrop shape). experiments were conducted under various boundary conditions (reynolds numbers, attack angles, and flow velocity). the reason behind using this technique is attributed to the dimples of various shapes generate eddies that retard or obstruct the flow's separation from the airfoil surface. these findings revealed an improvement in the airfoil's aerodynamic performance (lift and drag). dilek f. [11] conducted a study to examine the unstable flow with increasing incidence angles and boundary conditions, re = 103, and different angles of attack with naca 0012 wing, the vortex pattern was calculated using the formal figure. the flux shows to be very laminar, and the boundary layers were very thick at this reynolds number. at lower http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ muhammad s. kazem, dhafer a. hamzah /al-qadisiyah journal for engineering sciences 14 (2021) 092–098 93 angles of attack, there are flux, vortex detachment, and separation. for the naca 0012 wing, the unstable 8 ° vortex can be observed. angles of attack usually range from 0 ° to 90 °. it is suggested that the aerodynamic forces induce an oscillation until a peak in the amplitude spectrum of the lift coefficient (cl) is reached. at this low reynolds number, the time-averaged streamlines, pressure, and skin friction coefficients are evaluated to see vortex development and separation from the airfoil upper surface. pavlenko a. m. et al. [12] conducted an experimental study to investigate the evolution of hydrodynamic turbulence that resulted from the low-frequency vibrations. the results were obtained by using a low-velocity hot wire intensity meter. the results indicated that the vibrations in the wall generated disturbances in the separation region. the separation of the laminar boundary layer promoted the growth of the positive beams with the subsequent turbulence of the wall flow. zhou y. et al. [13] conducted a numerical study by placing a small plate near the front edge of the airfoil. the purpose of this plate is to create an overlap between the eddies produced by the plate and the boundary layer on the airfoil surface to control the flow separation. the researchers focused on mach number, plate length, and angle and their effect on controlling flow separation. the results indicated that mach numbers less than (0.5) have the potential to preserve the airfoil (naca 4405). however, mach numbers greater than (0.5) can only obtain a slight improvement. mahdi n. et al. [14] conducted a study to investigate delta airfoils' performance and flow characteristics with sweep angle (65˚) and coarse axial ribs. it is compared to a smooth-surface delta wing. the study investigated the effect of the ribs on (diameter, distance, and location) of vortices from the airfoil surface. the results indicated that the airtight type is positive in increasing the lift and reducing the drag. the ribs increase the flow near the upper surface except for the area near the summit. sreejith b.k. & a. sathyabhama [15], conducted a numerical and experimental study to verify the effect of the leading tuber with different ailerons at different angles of attack and reynolds number 105. the stall occurred at an angle (12˚) in the normal wing, as observed from experimental results. the results indicated in this study that all airfoils with tuber have the same stall angle except (a2w15.5) where the stalling occurred at the angle (10˚). by evaluating past research, we discovered a dearth of interest in studying cylinder rotation on the upper surface of the wing. therefore, this work will focus on studying the extent of its impact on aerodynamic performance and its potential to enhance performance. 2. describe the problem and boundary conditions in this work, the effect of cylinder rotation on the airfoil's upper surface is considered, to improve airfoil performance. the influence of cylinder diameter was significant to obtain excellent work and satisfy the desired goal (the cylinder diameter is the same for all situations). the number of rotations of the cylinder varied according to the location. the cylinder is placed at three places that can separate the boundary layer from the length of the chord's anterior edge of an airfoil. table 1 shows. the boundaries of the conditions were angles of attack (0˚,2˚,4˚,6˚,8˚,10˚,12˚,14˚,16˚), flow velocity (10 m/s) and reynolds number (105). table 1. data & position cylinder. position cylinder n (rpm) diameter cylinder (cm) 25% c 124 0.54 50% c 143 0.54 75% c 172 0.54 3. setup 3.1. grid and computational domain grid and computational domain are both crucial to obtain accurate results. a two-dimensional rectangle was created (3*1.35) m, and the rectangle was 20 double the length of the chord. the height was 9 double the length of the chord. it was intended to obtain a fully developed flow. in front of the airfoil is 5 double the chord length, and behind it is 15 double length of the chord, to avoid any impact on the walls zhong w. [16] shown in fig .1 a and b. the boundary conditions were hare's reynolds number (105) and flow velocity (10 m/s); the flow is considered to be stable, non-viscous, and incompressible. the semi-implicit method was used for the pressure-related equation computational. the wall y-plus parameter is a dimensionless parameter that shows the accuracy and convergence of the results, with a value less than or equal to one indicating more accurate aerodynamic results. using the following equations, calculate y – plus. 𝑌 = 𝑌+𝜇 𝜌 𝑢∗ (1) where: 𝑢∗ = √ 𝜏𝑤 𝜌 (2) 𝜏𝑤 = 0.5𝐶𝑓 × 𝜌 × 𝑈∞ 2 (3) 𝐶𝑓 = [2𝑙𝑜𝑔𝑅𝑒 − 0.65] −2.3 , for ( re < 109 ) (4) 𝑅𝑒 = 𝜌𝑐𝑈∞ 𝜇 (5) a 94 muhammad s. kazem, dhafer a. hamzah/al-qadisiyah journal for engineering sciences 14 (2021) 092–098 b figure 1. grid for domain 3.2. grid-independence it is crucial to study the relationship between the mesh size and the accuracy of the solution increase in the number of cells must be investigated against variation in the convergent solution. the appropriate test methodology for the mesh independency has been adapted, fish et al.[17] the current work was carried out by selecting five meshes to check the number of cells ranged from (125536) to (633421), and this selection was implemented at the angle of attack (12˚). the convergence of lift and pull values occurred at a network consisting of cells of (517613), and the difference was almost negligible. table 2. grid-independence iteration grid y+ cl cd 923 125536 3.5 0.93419 0.03659 1846 281562 2.5 1.20001 0.04993 3218 374648 1.5 1.23986 0.05927 4509 517613 0.9 1.40609 0.06562 6340 633421 0.8 1.41352 0.06684 3.3. turbulence model and governing equation it is essential to find or use a disturbance model that can capture the phenomenon of transition. the current work assumes incompressible, turbulent, viscous, steady, and 2-dimensions flow with an adopted (sst k-w turbulence model), [15, 17, 18]. for the kinetic energy of perturbation k and the specific dissipation rate w, see the equations below. continuity equation 𝜕𝑢 𝜕𝑥 + 𝜕𝑣 𝜕𝑦 = 0 (6) momentum equation 𝜌𝑢 𝜕𝑢 𝜕𝑥 + 𝜌𝑣 𝜕𝑢 𝜕𝑦 = − 𝜕𝑃 𝜕𝑥 + 𝜕 𝜕𝑦 [𝜇 ( 𝜕𝑣 𝜕𝑥 + 𝜕𝑢 𝜕𝑦 )] (7) 𝜌𝑢 𝜕𝑣 𝜕𝑥 + 𝜌𝑣 𝜕𝑣 𝜕𝑦 = − 𝜕𝑃 𝜕𝑦 + 𝜕 𝜕𝑥 [𝜇 ( 𝜕𝑣 𝜕𝑥 + 𝜕𝑢 𝜕𝑦 )] (8) sst k-ω turbulence model 𝜕 𝜕𝑡 (𝜌𝑘) + 𝜕 𝜕𝑥𝑖 (𝜌𝑈𝑖 𝑘) = �̃�𝑘 − 𝛽 ∗𝜌𝑘𝜔 + 𝜕 𝜕𝑥𝑖 [(𝜇 + 𝜎𝑘 𝜇𝑡 ) 𝜕𝑘 𝜕𝑥1 ] (9) 𝜕 𝜕𝑡 (𝜌𝜔) + 𝜕 𝜕𝑥𝑖 (𝜌𝑈𝑖 𝜔) = 𝛼𝜌𝑆 2 − 𝛽𝜌𝜔2 + 𝜕 𝜕𝑥𝑖 [(𝜇 + 𝜎𝜔𝜇𝑡 ) 𝜕𝜔 𝜕𝑥𝑖 ] + 2(1 − 𝐹1)𝜌𝜎𝜔2 1 𝜔 𝜕𝑘 𝜕𝑥𝑖 𝜕𝜔 𝜕𝑥𝑖 (10) where: β* is 0.09, and 𝜎𝜔2 is 0.856. f1 is the blending function, s is an invariant measure of the strain rate. in ( k-ε model), the blending function equals zero when it is away from the surface, but in (k-ω model), it is one inside the boundary layer menter et al. [19]. �̃�𝑘 , definition production limiter, the purpose of its use in the sst model is to eliminate or prevent the accumulation of disturbances that occur in stagnation areas. calculate all other constants through a combination of (k-ω) and (k-ε) models via 𝛼, 𝜎𝜔, 𝜎𝑘 , 𝑒𝑡𝑐. menter et al. [19, 20]. 4. results and discussion the study conducted a numerical analysis to investigate the problem in the flow control due to a cylinder placed on the upper surface of the airfoil with a fixed diameter of (0.54 cm), at different positions (25%, 50%, 75%) the length of the line from the front edge of the airfoil where the velocity of free flow was (10 m/s). 4.1. validation to determine the validity and convergence of current search results. lift coefficients were calculated at various angles of attack (0° to 10°), then compared with those obtained in previous research e.n. garcia et al. [21] shown in fig. 2 the study conditions under which the current research was conducted were similar to those used in previous studies. one of the most critical conditions is naca6409, which is the same used in current research. there was a difference between the study previous and the current study, (the different circumstances of the two studies). found an acceptable error rate at an angle of attack (10°) of (1.46%). muhammad s. kazem, dhafer a. hamzah /al-qadisiyah journal for engineering sciences 14 (2021) 092–098 95 figure 2. lift coefficients of the present research and researcher [8] with the angle of attack 4.2. lift and drag lift on an airfoil is often caused by the angle of attack and the form of the airfoil. to ensure the airfoil deflects the incoming air, the airfoil at an angle that produces a force the airfoil in the opposite direction of deflection was oriented. moreover, aerodynamic force, is classified as lift and drag. a lift can be produced on many foil shapes, but the cambered airfoils can do so even at zero attack angles sharma et al. [22]. from fig .3-a, is observed that the lift coefficient of the smooth airfoil starting from a value higher than zero, and this proves the hypothesis above about the zero attack angle and its output for the lift coefficient. as shown fig. 3-a, it can be seen that the best lifting coefficient is at the position (25%c) where the percentage of improvement was in the lift coefficient (24.45%), and this is owing to the cylinder's position and its critical function in delaying the boundary layer's separation process. fig. 3-b, is shown the airfoil behavior is illustrated in relation to the drag coefficient, demonstrating that an increase in the angle of attack results in an increase in the drag coefficient. however, the proportions ranged in increasing the drag coefficient according to the effect of the cylinder position at the other positions. a b figure 3. lift & drag coefficients with angles of attack 4.3. velocity contours the area of separation of the flow from the airfoil surface, can be possibly determined, it is also possible to observe the effect of the position of the cylinder on the performance of the aileron (delaying the separation process). in fig. 4-a, the separation in the airfoil is observed to be smooth at angle 12˚; from the gradient, see the separation area, as shown in fig. 4-a. fig. 4-b explains the velocity distributions in the airfoil with the cylinder at the position (25%c). note that the process of re-bordering the boundary layer by adhesion to the upper surface of the airfoil, which explains the increase in the lift coefficient at the angle of attack (12˚). fig. 4-c shows the cylinder at the position of (50%c), from the gradation of colors, see process of separation of the flow occurred early and before the cylinder. the position of the cylinder becomes ineffective inflow. fig. 4-d represents the velocity trends of the cylinder at (75%c). through the results and contour, it is found that the cylinder is in the area of separation. thus, the flow cannot be re-adhered at the airfoil surface which becomes utterly ineffective. a 96 muhammad s. kazem, dhafer a. hamzah/al-qadisiyah journal for engineering sciences 14 (2021) 092–098 a b b c c d figure 4. velocity contours 4.4. pressure coefficient fig. 5 represents the air pressure coefficient on the naca 6409 airfoil were (fig. 5-a) the smooth airfoil, (figs-b, c, d) for the modified airfoil, at the angle of attack (12˚). where the negative value indicates the pressure factor on the upper surface of the wing. the positive value represents the pressure coefficient on the lower surface of the wing. the results obtained indicate that the more negative the pressure coefficient on the upper surface, the higher the lift coefficient. all of the above is based on bernoulli's principle. in fig. 5-b, two locations (1 and 2) change the shape of the curve as a result of the cylinder's action on the wing surface at 25% °c. in fig. 5-c, it shows the extent of the effect of the cylinder rotation at a position (25%). a change occurred in the shape of the lower curve at region (1), which represents the upper surface of the airfoil. the reason for the change is the effect of the cylinder rotation. fig. 5-d, where the cylinder position is 75% c. the curve is similar to that of the smooth airfoil, when compared to fig. 5-a, the result indicates, that there is no effect of cylinder rotation on the flow in position 75% c . a b muhammad s. kazem, dhafer a. hamzah /al-qadisiyah journal for engineering sciences 14 (2021) 092–098 97 c c d figure 5. pressure coefficient with position 5. conclusions a numerical study was performed on the airfoil (naca 6409) to investigate aerodynamic performance with and without cylinder rotation on the airfoil's upper surface. three positions of the cylinder (25%,50%,75%) were chosen from the front edge of the airfoil. the results showed the following: 1there is a difference in the coefficient of lift and drag values using roller rotation technology and without roller rotation on the wing's upper surface (naca6409). this means that the lift coefficient increases with the increase in the angle of attack due to the rotation of the cylinder and the resulting pressure difference around the airfoil. the lift coefficient reaches its maximum value at an angle (12), and the stall angle occurs at an angle (14), the angle at which the boundary layer separated. as shown fig .6. velocity streamlines 2the rate of increase in lift coefficient was (24.45%) position (25%). at the location of the cylinder (50%), there was no significant improvement in aerodynamic characteristics despite the increase in the lift coefficient for the angles (0˚, 2˚). after these angles, an early separation occurred at an angle of attack (4), and this is entirely undesirable. the site (75%) has a slight increase in the lift coefficient of (3.7 %). 3lift coefficient increases with increasing angle of attack in case the rotation of cylinder is presence or not. from the results discussed, the site (25%) is the best in terms of optimization used in this work. figure 6 velocity streamlines contour at an angle of attack (14°) .references [1] h. park, d. lee, w.-p. jeon, s. hahn, j. kim, j. kim, j. choi, h. choi, drag reduction in flow over a two-dimensional bluff body with a blunt trailing edge using a new passive device, journal of fluid mechanics, 563 (2006) 389. 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[15] b. sreejith, a. sathyabhama, experimental and numerical study of laminar separation bubble formation on low reynolds number airfoil with leading-edge tubercles, journal of the brazilian society of mechanical sciences and engineering, 42(4) (2020) 1-15. [16] w. zhong, t. zhang, t. tamura, cfd simulation of convective heat transfer on vernacular sustainable architecture: validation and application of methodology, sustainability, 11(15) (2019) 4231. [17] f.e. fish, j.m. battle, hydrodynamic design of the humpback whale flipper, journal of morphology, 225(1) (1995) 51-60. [18] h. shah, s. mathew, c.m. lim, numerical simulation of flow over an airfoil for small wind turbines using the $$\gamma-{\text {re}} _ {\theta} $$ γ-re θ model, international journal of energy and environmental engineering, 6(4) (2015) 419429. [19] f.r. menter, m. kuntz, r. langtry, ten years of industrial experience with the sst turbulence model, turbulence, heat and mass transfer, 4(1) (2003) 625-632. 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[22] a. sharma, s.g. kumar, d.n.g. ratha, evaluation of flow behavior around an airfoil body, 2012. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٥ evaluation of the relationship between compressive strength and upv of hsc exposed to high temperatures sallal rashid al-owaisy college of engineering wasit university abstract: an experimental program was adopted in this study to investigate the degree of dependency on the using of ultrasonic pulse velocity (upv) to evaluate the residual strength of concrete exposed to high temperatures as in the case of fires. this experimental program focus on the relationship between compressive strength and upv of high strength concrete (hsc) after high temperature exposure. the tests were carried out using 100mm cubes. three concrete mixes were used with target compressive strengths of 40 mpa, 60 mpa and 80 mpa. totally fifty four concrete cubes were tested in this study. the specimens were divided into three groups according to their original compressive strength. four temperature levels of 150 o c, 350 o c, 500 o c and 700 o c were adopted. three specimens from each group were heated to each temperature level, cooled and then tested. while, six specimens from each group were tested as reference specimens without heating. the test results show that both concrete compressive strength and upv decreased after high temperature exposure. another observation is that at temperatures (150 o c and 350 o c ), the normal strength concrete (nsc) suffered higher percentage loss in strength than hsc, while the opposite stands at 700 o c. also it is observed that the upv showed higher percentage loss than in compressive strength for both nsc and hsc at temperatures of 350 o c and higher. finally, it was found that the upv-temperature behavior differs than the compressive strength-temperature behavior. keywords: concrete, high strength concrete, elevated temperatures, nondestructive, ultrasonic pulse velocity. ا�����h ا+داء<���f ا�� �e �d -��و-� ا�bc�0ط وا��).�ت �)ق ا�?)<�= �������� ����� ��ر.�ت �iارة ����� � $ ل را�j ��1 ا��)�� آ��� ا�,%��� lوا� ��-�. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٦ :������ � �� ��� � �� �� �� �� ���� �� �� ��� �� ������ ��� � ��� � �� � !"#$%& ���"'� � ( )� �*�� +"*���� ��*� � ��� � �� � �,�� -. ���"�� & ���� � /���.� ��.� �� �� ���"'�� ���" �%"��,.� 0�,1 ��� �� ���"�� )� ��� +"��� -� 2���� ��� �%"��,.� �'���� ���"'�� � �'� ���'�� ������ �*3 ��� �*�"� �*� "*�� ���"�� . +�*5% 6"�'� ����� ��%"��, 7�"�% � �,��"� +"���5� 899 �.� ( /�"�*� ������� ���"'�� ��%"��, +"!., �: : �"�� �� "�� )<9 (=9 � >9 ����% /�.�@ .( /�"�� ���� �� ��,���� �.�� +"����� �� b< c"���� ( d��"*�� �*: : -*� "����'� �� �"�� �������� ���"'�� -. c . �*�� )� �*�� ����� +"����� ����1 �"�� �� "��)8b9 (eb9 (b99 � f99 �*��� ���3� .( "���� �� g�� ���� ���#� )� �� ���� -� +��� �: ��� )� �� ���� ��� � ���� �� �� ��"�% �: : +$� . )� �� ���� �� � ���� �� �� +"���� ��� h�� �� "�%�� �*��"�� )� �*�� -� "�$���� ��� ������ ��"�%� ���#� . ���"�� )� ��� -� 2���� ��� �"�'%� ������ ��� � ��� � �� g���� !"#$%& ���"'� �1 i3"�%� +��j1 . j��� "�� ��� ���"�� ���"'�� + � g.� �� -. 1 ���% ��,� ���"�� & ���"'�� + � �%"��,� �1)8b9 � eb9 �*��3� ���� ( "*�%�� -� 2���� ��� 6��� ����f99 ���3� ���� . k�%"�� "�� ���1 h'% �� �%"�� ������ ��� � ��� � �� �1 j��� "�� � ��l� �1 -� ���"�� )� �� +"��� -� 2���� �% !"#$%& ���"'�eb9 �%"*��,� �*� �*�� g��� ���3� ���� �,� � ���"'�� ���"�� & ���"'�� ���" �%"� .c ��,1� ( m.�,� )� ��� d� ������ ��� � ��� � �� ��� � �� �1 j��� )� ��� d� !"#$%& ���"'� � � . introduction: the assessing of concrete strength in existing structures by ultrasonic pulse velocity (upv) nondestructive test is of considerable interest in the field of civil engineering. upv and other nondestructive test methods measure some others properties of concrete than its mechanical strength. however, the evaluation of in-situ concrete strength is carried out by means of an established correlations of these properties with strength. therefore, the reliability of assessing the concrete strength primarily depends upon the precision of the established calibration. the relationship between upv and concrete strength is generally not unique. this arises from the diversity in the existing relations between the measured characteristic and the factors making up concrete strength, among others: cement contents, type of aggregates, bond between cement paste and aggregates and water cement ratio. on the other hand, exposing of concrete structures to high temperatures as in the case of accidental fires deteriorates the concrete mechanical properties. the degree of deterioration depends on many factors such as concrete composition and the type of the induced stresses in each test. many previous studies showed that after high temperature exposure, the behavior of compressive strength differs from other mechanical properties such as splitting tensile strength and modulus of rupture. also, it was found that its behavior differs from the behavior of some nondestructive tests such as rebound number and upv. the aim of this paper is to study the behavior of both concrete compressive strength and ultrasonic pulse velocity of high strength concrete (hsc) and to evaluate the relationship between them after exposure to elevated temperatures. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٧ experimental program: fifty four concrete cubes were used to investigate the effect of high temperatures on both concrete compressive strength and ultrasonic pulse velocity (upv) and to evaluate the relationship between these two properties after high temperature exposure. the cubes were 100mm in size and were divided into three groups a, b and c depending on their target compressive strength. three concrete mixes with three different target compressive strengths of (40, 60 and 80 mpa) were used in this study. table 1 summarize the mix proportions of the three groups. the maximum size of coarse aggregate was 9.5mm as recommended by aci 363r-92 (1). after de-molding, the specimens were cured for about 21 days in water containers, the water temperature in the containers ranged from 20 oc to 30 oc. the curing was initiated when the concrete surface begins to dry as recommended by aci 308r-01 (2). after curing, the specimens were removed from the water containers and were dried in the laboratory environment for a bout 7 days until the time of heating at age of twenty eight days. each group consisted of eighteen specimens. six specimens from each group were tested at room temperature as reference specimens. while the rest twelve specimens from each group were heated to different levels of temperature using electrical furnace at a constant rate of (2 oc/min) to avoid explosive spalling of specimens. three specimens from each group were heated to each temperature level. the adopted temperature levels were ( 150, 350, 500 and 700oc ). after heating to each particular temperature, the specimens were air cooled in the laboratory environment for about 20 hours. then after, the specimens were tested nondestructively using upv test and destructively using 3000 kn capacity hydraulic testing machine, respectively. results and discussion: the results of compressive strength and upv both before and after exposure to high temperatures for the fifty four cubes are represented in this section. compressive strength: figure 1 shows the residual compressive strength of groups a, b and c. the original strength of the three groups were (41.3, 57.8 and 76.6 mpa) respectively. after exposure to the whole range of the studied temperatures, the residual compressive strength was lower than the original compressive strength. at temperature 150 o c, the residual strength of group a was about 35.5 mpa. while the residual strengths for groups (b and c) were about (50.9 and 73.9 mpa) respectively. figure 2 shows that the percentage loss in strength still lower than 15% for all groups at 150 o c. it is noticed that the lower strength specimens suffered higher percentage loss in strength than the higher strength specimens. at temperature 350 o c, the compressive strength of the lower strength concrete cubes (group a and b) were higher than at temperature 150 o c. the percentage residual strengths of al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٨ groups a and b at temperature 350 o c were 87.4 % and 90 % compared to 85.9 % and 88 % respectively at temperature 150 o c. while for higher strength cubes of group c, the compressive strength suffered further decrease at temperature 350 o c. this behavior was noticed in many previous studied for normal strength concrete (3, 4, 5) and high strength concrete (6, 7) .it is shown in figure 2 that at temperature 500 o c, the percentage residual compressive strength for the three groups was in the range of (60% to 63%). however at temperature 700 o c, the higher strength concrete lost higher percentages than lower strength concretes. where the percentage residual strengths at temperature 700 o c for groups a, b and c were about (34%, 32% and 29%) respectively. ultrasonic pulse velocity (upv): ultrasonic pulse velocity was recorded for all cubes before testing under the compression machine. at least, three readings of upv were recorded for each cube. each point in the curves represents the average reading of at least three cubes. the ultrasonic pulse velocites of the original specimens of group a, b and c were ( 4.45, 4.72 and 4.88 km/sec) respectively. figure 3 shows the relationship between upv and temperature for the three groups. from the observation of figure 3, it is obvious that upv suffered continuous decrease as temperature increase both for normal and high strength concrete. similar sequence of reduction was observed in many previous studies (4, 5, 6) . another notice is that up to temperature 500 o c, the upv values of the higher strength specimens still higher the those of lower strength specimens. while at temperature 700 o c, group b specimens retained lower upv values than those of lower strength specimens ( group a). figure 4 shows the residual upv values at all the studied temperatures as a percentage ratio of the original upv values. as shown in figure 4, the percentage loss at temperature 150 o c was almost the same for the three groups and was about 6%. while at 350 o c, the percentage residual velocities were (62.7%, 73.7% and 75.6%) for group a, b and c respectively. similar sequence of reduction was recorded at temperature 500 o c. thus, between 350 o c and 500 o c, the lower strength specimens show higher loss percentages in upv than the higher strength specimens. comparison between the versus temperature behavior of upv and compressive strength: figure 5, figure 6 and figure 7 show a comparison between the behavior of concrete compressive strength and upv after exposure to temperatures up to 700 o c. the comparison is in the means of percentage residual strength and upv versus temperature for each group. from the observation of figure 5 and figure 6 it can be noticed that the behavior of residual upv differs from that of compressive strength, especially at the region between room temperature and 500 o , where the compressive strength shows three different steps. the residual compressive strength decreased at temperature 150 o c composing a descending line between room temperature to 150 o c. higher percentage residual strength is then retained at temperature 350 o c al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٤٩ forming an ascending line between 150 o c and 350 o c. then after, a second region of strength drop is noticed between 350 o c and 500 o c. on the other hand, the upv curves show continuous decrease in strength as temperature increase and no such different regions can be recognized in the upvtemperature curves. in figure 7, it is noticed that the behavior of compressive strength-temperature curve of group c specimens is somewhat differs than for groups a and b. where, the residual strength at temperature 350 o c still lower than at temperature 150 o c. however, the slope of the curve at this region is not sharp and can be considered as semi-flat as compared to the slope of the curve between 350 o c and 700 o c. thus it can be concluded that upv and compressive strength have different behaviors when concrete is exposed to elevated temperatures. another difference between upv and compressive strength-temperature curves is that the percentage loss is higher for upv as temperature increase beyond 150 o c which leads to another conclusion that for both normal strength (nsc) and high strength (hsc) concretes, the evaluation of compressive strength of concrete exposed to high temperatures using upv-strength correlations made from unheated specimens is conservative beyond 150 o c. cnclusions: within the limits of the studied range of variables and depending on the experimental results of this study, the following conclusions were obtained: 1ultrasonic pulse velocity and compressive strength for both nsc and hsc decreases after high temperature exposure. 2 ultrasonic pulse velocity and concrete compressive strength exhibit different behaviors after exposure to high temperatures. 3upv suffers higher percentage loss as compared to compressive strength between 350 o c and 700 o c. for concrete with original target strength of (40, 60 and 80 mpa), the percentage residual strength at 350 o c was in the range of (87% to 90%), while the percentage residual upv at the same temperature was in the range of (62 % and 75 %). 4depending on the previous conclusion, it can be concluded that the using of upv-compressive strength correlations made from unheated specimens to evaluate the compressive strength of concrete exposed to high temperatures gives conservative estimations beyond 150 o c. references: 1aci committee 363r, 1992, "state-of-the-art report on high-strength concrete," (aci 363r-92), aci manual of concrete practice, american concrete institute, detroit, 55 pp. 2aci committee 308r, 2001, "guide to curing concrete," (aci 308r-01), aci manual of concrete practice, american concrete institute, detroit, 31 pp. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٠ 3al-owaisy, s. r., "post heat exposure behavior of bond strength and concrete compressive strength," iraqi journal for civil engineering, march 2004, pp. 135-149. 4al-owaisy, s. r.; and al-chalabi, n. n., "nondestructive tests on concrete exposed to temperatures up to 700 o c," journal of engineering and development, vol.8, no.1, april 2004, pp. 29-39. 5al-owaisy, s. r., "post heat exposure properties of steel fiber reinforced concrete," journal of engineering and development, vol.10, no.2, june 2006, pp. 194207. 6habeeb, g. m., “residual mechanical properties of high strength concrete subjected to elevated temperatures,” ph.d. thesis, college of engineering, department of civil engineering, al.mustansiriyah university. 7 phan, l. t., and carino, n. j. " review of mechanical properties of high-strength concrete at elevated temperatures," journal of material in civil engineering, february, 1998, pp. 5864. table (1): mix proportions. group notation cement kg/m 3 fine aggregate kg/m 3 coarse aggregate kg/m 3 water kg/m 3 w/c super plasticizer target strength mpa a 360 717 1147 162 0.45 0% 40 b 490 669 1065 162 0.33 1.5% 60 c 570 645 1040 162 0.28 3% 80 0 100 200 300 400 500 600 700 800 temperature ( c) 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 c o m p r e ss iv e s tr e n g th ( m p a ) o group a group b group c figure 1: compressive strength-temperature relationship. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥١ 0 100 200 300 400 500 600 700 800 temperature ( c) 20 30 40 50 60 70 80 90 100 110 r e si d u a l c o m p r e ss iv e s tr e n g th ( % ) o group a group b group c figure 2: percentage residual concrete compressive strength. 0 100 200 300 400 500 600 700 800 temperature ( c) 0.0 1.0 2.0 3.0 4.0 5.0 v e lo c it y ( k m /s e c ) o group a group b group c figure 3: upv-temperature relationship. 0 100 200 300 400 500 600 700 800 temperature ( c) 10 20 30 40 50 60 70 80 90 100 110 r e si d u a l v e lo c it y ( % ) o group a group b group c figure 4: percentage residual upv. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٥٢ 0 100 200 300 400 500 600 700 800 temperature ( c) 10 20 30 40 50 60 70 80 90 100 110 r e si d u a l s tr e n g th o r u p v ( % ) group a compressive strength up velocity o figure 5: compressive strength and upv-temperature relationship of group a. 0 100 200 300 400 500 600 700 800 temperature ( c) 10 20 30 40 50 60 70 80 90 100 110 r e si d u a l s tr e n g th o r u p v ( % ) group b compressive strength up velocity o figure 6: compressive strength and upv-temperature relationship of group b. 0 100 200 300 400 500 600 700 800 temperature ( c) 10 20 30 40 50 60 70 80 90 100 110 r e si d u a l s tr e n g th o r u p v ( % ) group c compressive strength up velocity o figure. 7: compressive strength and upv-temperature relationship of group c. article al-qadisiyah journal for engineering sciences 13 (2020) 099–108 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: khaled.alfarhany@qu.edu.iq (khaled al-farhany) https://doi.org/10.30772/qjes.v13i2.653 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. experimental investigation of mixed convection on a rotating circular cylinder in a cavity filled with nanofluid and porous media ahmed dhafer abdulsahib a, khaled al-farhany a* adepartment of mechanical engineering, university of al-qadisiyah, ad-diwaniyah (58001), iraq a r t i c l e i n f o article history: received 03 may 2020 received in revised form 16 june 2020 accepted 26 june 2020 keywords: nanofluid porous media two layers circular cylinder rotating cylinder mixed convection a b s t r a c t the present study, experimentally investigated the mixed convection in a square enclosure partitioned in two layers. the experiments were performed with al2o3–water nanofluid (upper layer) and superposed porous medium (lower layer) with an adiabatic rotating cylinder at the center of the cavity. the boundary conditions of the experimental study were; the upper and lower walls were assumed adiabatic, the right wall was heated, and the left wall was cooled. experimentally, 15 k-type thermocouples and thermal imaging camera were employed to measure the temperatures distribution inside the cavity when the concentration of nanoparticles (ɸ = 0.06), the temperature difference (∆t) between the cold and hot walls was (6, 8, and 10) °c, and angular rotational velocity (-50, -25, 0, 25, and 50) rpm. the results of experimental data showed that in general, the distribution of temperatures was very well along the upper half of the enclosure, while in the lower half the temperature distribution was confined near the hot wall region. when the circular cylinder rotates in counter-clockwise, it noted that the effect of speed is evident in the downside of the cylinder, while the temperature distribution in the left upper part of the enclosure decreasing. when the circular cylinder rotates in the clockwise direction, the results showed that the effect of cylinder rotation was around cylinder only. moreover, the results demonstrated that the increasing temperature difference leads to a noticeable increment in the intensity of the flow. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the studies of enhancement convection heat transfer inside the cavity, that has received the attention of researchers because of its multiple engineering applications such as solar collectors, nuclear reactors, electronic equipment cooling, and heat exchangers [1-3]. by adding solid nanoparticle to base fluid, the enclosure is developed by repair its geometry, adding fins or baffles and inserting objects inside the enclosure in fixed case or rotating case, etc. [4-6]. for controlling and enhancement of the convection heat transfer, a liddriven wall is used [7-14] and a rotating cylinder used inside the enclosures [15]. when using rayleigh number 1-1400 show the influence of the rotating cylinder to increasing thermal transfer by lewis [16]. wu-shung et al. [17] find the contribution of the counter-clockwise rotation cylinder in the heat transfer 60% when used gr/re2 is 10 3 . it was compared with previous studies and the effect of the rotating cylinder on the heat transfer and flow patterns by yang et al. [18]. natural, mixed, and forced convection http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i 100 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 studied by misirlioglu and aydin [19] found when the cylinder rotates at a high speed, the maximum heat transfer is achieved. costa et al. [20] appear the important effect of cylinder thermal properties inside enclosures on heat transfer. hussain et al. [21] explain the effect of richardson number and reynolds number on average nusselt number, heat transfer, and the field of fluid, as well as the effect of changing the cylinder location on the convection heat transfer. roslan et al. [22] using several types of nanofluids with different concentrations and showed that rising the heat transfer when increasing the nanofluid concentrations, as well as the effect of heat transfer when the cylinder rotates in clockwise and counter-clockwise direction, the high heat transfer was found when using nanoparticles with the high concentration and good conductivity values when the rotating cylinder was in the centre of the cavity. by using a rotating cylinder inside horizontal annulus matin et al. [23] explained the effect of reynolds number on the average nusselt number, as well as the effect of the location rotating cylinder. mixed convection mhd was studied by selimefendigil et al. [24] and show an increase in entropy and heat transfer with increasing concentration of nanoparticle. numerical study of a hot rotating cylinder inside a cooled walls square enclosure by liao et al. [25] and find average heat transfer at the rotating cylinder and the walls of the enclosure. shih et al. [26] show that the triangular enclosure has been shown the greatest ability to dissipate thermal energy compared to the circular enclosure. by using two rotating cylinders inside a three-dimensional cavity, using nanofluid with different concentrations study by selimefendigil et al. [27]. to enhance the heat transfer at two layers, a rotating cylinder has been added. mixed convection that studied by selimefendigil et al. [15] two layers nanofluid and porous medium inside the cavity and show the enhancement of nusselt number when the cylinder rotates. also two layers study by hussein et al. [28]. the experimental study within nanofluid enclosure investigations by researchers[29, 30]. solomon et al. [31] experimental study on the influence of the aspect ratio of square cavity on natural convection heat transfer with al2o3/water nanofluids. wen and ding [32] showed a reduced mean size of accumulation by applying a highshear homogenizer. joshi and pattamatta [33] found that the lower value of nusselt number when used (mwcnt/water), while get the higher value in (graphene/water) if compared with (alumina /water). khalili et al. [34] showed that the average size of the nanoparticles at the cold side wall was 3.10% higher than that along the hot wall. recently, many studies had been done with conviction/mixed heat transfer. a few studies have been done regarding using two layers (nanofluids and porous medium layers) with a rotating cylinder at different angular rotational velocity. in this study, a mixed convection on the square cavity having two different horizontal layers with a rotating cylinder (clockwise and counterclockwise) is investigated experimentally. the upper and lower walls of the cavity are insulated thermally while the right wall is heated and the left wall is kept at low temperature. 2. the experimental work this section describes the experimental rig design and its main components. it also shows the preparation of nanofluid and the type of porous medium used in the present work. 2.1. experimental rig this section shows the description of the main units of the experimental setup. fig. 1 and fig. 2 illustrate the schematic diagram of the experimental setup and the schematic diagram of the experimental set-up respectively. this includes the enclosure, the stepper motor used to rotate the cylinder, the heating unit (consists of a heater, a controller, and a dc power supply), the cooling unit (water bath at a constant temperature) and the measurement system (thermal camera, data logger tool, thermocouples, and pc). figure 1. schematic diagram of the experimental setup figure 2. experimental set-up apparatus: (1) flir e30bx thermal imaging camera, (2) ultrasonic waves apparatus, (3) mechanical stirrer, (4) sensitive balance, (5) data logger, pc, and test section. ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 101 2.2. test section fig. 3 shows the test rig which is a square enclosure. the top, bottom, front and back walls are made of perspex glass having a thickness of 0.5 cm. the rotating circular cylinder made of pvc in 3 cm diameter at the center of the enclosure with thermal properties shown in table 1. the right wall is made of the aluminum plate that heated by an electric heater to control the temperature. the left wall of the enclosure was designed from an aluminum heat exchanger to control the temperature by passing the water through it. stepper motor was used to obtain rotate the internal cylinder of the enclosure at different rotational speeds. three thermocouples were installed at each right and left walls to measure temperatures, and eight thermocouples were installed in the middle section of the cavity for measuring the temperature distribution inside the enclosure as shown in fig 4. these thermocouples are programmed by using arduino (mega) type with programming code. figure 3. enclosure assembly. table 1 the properties of perspex glass [35] physical properties density thermal expansion coefficient perspex glass (1.17-1.2) (g/cm2) (5-10)×105 (k-1) figure 4. thermocouples location inside the enclosure 2.3. formulation and characterization of porous media the porous medium is an object consisting of a fixed solid part called a solid matrix that contains empty spaces that can be filled with fluid. the solid matrix that used in present work made of glass bead with diameter 3 mm as shown in fig. 5. the properties of the glass bead sphere take from table 2. the porosity (ε) and permeability (k) of the porous medium are computed from eqs. 1 and 2 respectively. (1) (2)  the mean value of the calculated porosity values for glass bead (3) mm diameter ε=0.37.  the average value of the permeability for glass bead (3) mm in diameter (k=7.65х10-9 m2). figure 5. the porous media used in this work. table 2 thermo-physical properties of some glass [36]. material s( kg/m 3) cps(pa.s) ks(w/m.k) glass bead 2507 670 0.78 glass window 2800 800 0.81 soda-lime 2500 750 1.4 glass window 2700 780 0.78 2.4. preparation of nanofluid in the current work, al2o3 nanoparticles are used having an average size between 40 nm and 80 nm and purity equal to 99.99%. the preparation of the nanofluid requires several processes that are summarized in the following points: 1void solid solid total v v v v     2 3 2 150(1 ) p d k     102 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 1to calculate the nano-powder weight for all concentrations using eq. 3 : (3) 2the sensitive balance that has been used to get the required quantity of mass as shown in table 3. 3to obtain an efficient and uniform distribution of nanoparticles as well as a steady mixture by using ultrasound waves (sonication bath for 4 hours). 4use arabic gum [37] with 0.25% of base fluid like surfactants for improving the stability of the nanofluid. 5to ensure the homogeneity of the mixture and attain the required volume fraction of the nanoparticle using the mechanical stirrer for 1 hour. table 3. mass of al2o3 nano-powder for different concentrations fig. 6 shows how the prepared nanofluid, using the above points, is used in the test rig. figure 6. nanofluid in the testing device 2.5. measuring the thermo-physical properties of the nanofluid in heat transfer, the thermophysical properties of the nanofluid play a significant role. the density, effective viscosity, and thermal conductivity of the nanofluid are computed from eqs. 4 to 6. these parameters were introduced in the study achieved by pak and cho [33] and listed in table4. (4) the dynamic viscosity is fined by using (brinkman model): (5) the thermal conductivity is fined by using (maxwell correlation): (6) table 4. the variation of the nanofluid (al2o3 water) thermo-physical properties with the nanoparticles solid volume fraction. no sample nf (kg/m 3) nf (pa.s) knf (w/m.k) 1 base fluid 997.07 0.001003 0.61300 2 φ=0.06 1175.5 0.0011708 0.72483 2.6. experimental procedure and calculations in this work, 45 experiments were performed. these experiments are divided into groups using different parameters; the concentration of nanoparticles, the difference in temperature between the hot and cold walls, and the insulated cylinder angular velocity. firstly, obtaining the thermophysical properties of the nanofluid at nanoparticle concentrations which are specified as (0.02, 0.04, and 0.06). secondly, the temperature differences between the cold and hot walls are taken equal to (6, 8, and10); which are not very large to avoid turbulent flow and also not very small to ensure a large flow in convective heat transfer. third, after measuring all temperatures at steady state condition readings are taken inside the cavity for each insulated circular cylinder angular velocity of -50, -25, 0, 25, and 50 rpm. the temperature difference between the cavity and the cylinder wall was within the limits of the mixed convective heat transfer represented by richardson's number (0.1 < ri < 10). this next section introduces the device initialization and verifies the accuracy of readings to carry out experiments in a wide range of different operational conditions. 2.7. device initialization there are several processes, represented the initialization of the device, that should be taken into account before conducting the experiments. 1. the enclosure was initially washed by distilled water to remove impurities and sediments. 2. half of the cavity is filled with a porous matrix, after that, the nanofluid is added completely to prevent the formation of gas bubbles so that accuracies of the test results are obtained. 3. heaters were placed at the hot wall including a controller and a suitable dc power supply; while a constant temperature water bath was used at the cold wall. 4. temperature results are shown by displaying the data of thermocouples every 10 seconds and saved in the computer. (1 ) nf f np      2.5 (1 ) f nf     ( 2 ) 2 ( ) ( 2 ) ( ) np f f np nf f np f f np k k k k k k k k k k         the concentration of nanoparticles % mass of al2o3 nanoparticles (g) 0.02 0.79415 0.04 1.588635 0.06 2.38343 p p bf ( / ) % = ( / )+( / ) p p bf m m m     ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 103 5. after all, temperatures are measured in a stable condition, the insulated circular cylinder is rotated at the required speed. 6. after stabilization is reached when the temperature difference is less than 0.25ºc in computer data for all points. finally, a thermal image is taken by the thermal imaging camera (flir e30bx). the experiments were conducted at the college of engineering/ university of al-qadisiyah / laboratories of the college of mechanical engineering. 2.8. achieve device readings to verify the device is working properly, the results of temperature distribution from a thermal camera were compared with eight thermocouples were installed in the middle section of the cavity. this includes two cases are shown in fig. 7 for the temperature distribution at the horizontal axis (i.e. x-axis) at the enclosure middle line. the comparison showed a very clear agreement for all cases and this is an important factor indicating the accuracy of the experimental part. (a) for water at (w=0, ∆t= 5) (b) for water at (w=-25, ∆t= 8) figure 7. comparison of the results of the temperature distribution between the thermal camera and thermocouple in the x-axis located at the enclosure middle–line. 3. results and discussion in this case, the results are shown form the test rig to study mixed convection heat transfer. the enclosure is filled with a porous media to half, after that, the nanofluid is added to full the enclosure. the experimental results were taken by a thermal imaging camera and thermocouples to show the distribution of the temperature inside the cavity. in addition, the experimental results were compared, as mentioned represented by the thermal imaging camera and thermocouples. the experiments are divided into four cases based on specific parameters as follows: 1. the concentration of nanoparticles (0.02, 0.04, 0.06). 2. the temperature difference between the cold and hot walls (6, 8, 10). 3. the angular rotational velocity of the insulated circular cylinder (-50, -25, 0, 25, 50) rpm. 4. the inner circular cylinder radius (r = 1.5 cm). 3.1. effects of rotating circular cylinder with temperature difference (∆t= 6) fig.8 and fig. 9 show the effect of angular rotational velocity on temperature distribution for al2o3-water, ɸ=0.06, ∆t= 6. it can be seen from this figure the rotation of the cylinder is studied in five cases: two angular rotational velocities in counter-clockwise, two angular rotational velocities in a clockwise direction, and when the cylinder is stationary. the figure shows that the distribution of temperatures is greater in the upper of the cavity, while it is confined near the hot wall in the lower half due to low permeability. the lower permeability impedes the fluid due to the use of low porosity of the porous matrix so that the conduction is dominant. when ꞷ=0 rpm the fluid moves by natural convection showing different temperatures between the right hot vertical wall and the cold left wall depending on the buoyancy force. therefore, the fluid flow moves from the right hot vertical wall towards the upper horizontal wall that is thermally insulated. then the flow completes its cycle down affected by the cold left vertical wall reaching the insulated lower horizontal wall. it can be noticed that the presence of a thermally insulated cylinder disturbs the movement of the fluid, resulting in a decrease the distribution of temperature in the upper half to the right of the cylinder (t=19 ºc), as well as in the lower half the influence of the hot wall and the buoyancy force are weak at the left of the cylinder and (t=17.3 ºc). when the circular cylinder rotates in a counter-clockwise at (ꞷ=-25 rpm). note the effect of speed is evident in the down of the cylinder where (t =19 ºc), while the temperature distribution in the left upper part decreases. this is because the part of the fluid due to the rotation of the cylinder collides with the porous medium layer with little permeability to rise towards the isolated upper wall so it will prevent the buoyancy force. at (ꞷ=-50 rpm) the influence of the rotational speed is more evident, where the same physical interpretation of (ꞷ=-25 rpm), but the density of the heat distribution is greater. in this case, the temperature at the bottom of the 104 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 cylinder increases from (19 ºc to 20.5 ºc). also, the distribution of heat increases relatively to include the area near the cold wall. at (ꞷ=25 rpm) the cylinder rotates clockwise direction where the influence of a rotating cylinder is opposite to the influence of buoyancy force. notice that the effect of the cylinder to rotate the fluid is limited to the area near it where (t=18.7 ºc), while the effect of buoyancy force appears in other areas, especially in the upper part of the cavity where (t=20.2 ºc). at (ꞷ= 50 rpm) the influence of the rotational speed of the cylinder is more influential than the buoyancy force inside most regions of the cavity, where the heat distribution density is greater. therefore, the temperature at the bottom of the cylinder increases from (19 ºc to 20.5 ºc). the heat distribution also increases relative to the area near the cold wall while it decreases at the upper right of the cavity. ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 105 106 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 107 108 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 3.2. effects of rotating circular cylinder with temperature difference (∆t= 8) fig. 10 and fig. 11 shows the effect of angular rotational velocity on temperature distribution for al2o3-water, ɸ=0.06, and ∆t= 8. the same five cases, related to the rotation of the cylinder, examined at ∆t= 6 are presented in this section for ∆t= 8. the physical interpretation of the cylinder rotation is the same as in the previous case, but the temperature difference here is greater. it is interesting to a reminder that the increase in temperature difference, results in increasing the intensity of the flow, which in turn leads to an increase in the buoyancy force. considering mixed convection heat transfer inside an enclosure, there are two effects on the production of flow vortices, the first is the buoyancy force and the second is the sheer force of the rotational circular cylinder. therefore, it can be seen that the influence of rotation of the cylinder is greater compared to the with the buoyant force if they are in the same direction while the effect of the cylinder is absent at lower speeds due to the high buoyancy force when there are different directions. 3.3. effects of rotating circular cylinder with temperature difference (∆t= 10) fig. 12 and fig. 13 shows the effect of angular rotational velocity on temperature distribution for al2o3-water, ɸ=0.06, ∆t= 01. the same five cases, related to the rotation of the cylinder, examined at ∆t= 8 are presented in this section for ∆t= 10. the physical interpretation of the cylinder rotation is the same as in the two previous cases, but the temperature difference here is greater. when (ꞷ=0 rpm) the fluid moves by natural convection heat transfer at different temperatures between the right hot vertical wall and the cold left wall. it can be seen that due to the difference in high temperatures, the distribution of heat includes most regions of the cavity, and because of the accumulation of temperatures under the cylinder where it reaches t=22.3 ºc. in general, when the cylinder rotates, the heat transfer inside the cavity increases, and the reason is the influence of buoyancy and cylinder rotational force. this shows the importance of mixed convection in increasing heat transfer. 4. conclusions from the experiment results, some important conclusions can be presented as follows: 1. in general, it is observed that the distribution of temperatures that is greater in the upper half of the considered enclosure, while it is confined near the hot wall in the lower half due to low permeability that impedes the fluid because of using low porosity of porous matrix so the conduction is dominant. 2. when (ꞷ =0 rpm), the fluid moves by natural convection heat transfer at different temperatures, the flow field inside the cavity is controlled only by the buoyancy force, and the presence of a thermally insulated cylinder disturbs the movement of the fluid. 3. when the circular cylinder rotates counter-clockwise, the effect of the speed is evident in the down of the cylinder, while the temperature distribution in the left upper part decreases because a part of the fluid due to the rotation of the cylinder collides with the porous medium 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[38] b.c. pak, y.i. cho, hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles, experimental heat transfer an international journal, 11(2) (1998) 151-170. 110 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 ꞷ isotherms lines( ) -50 -22 0 25 25 figure 8. temperature distribution in the enclosure at various angular rotation velocity for ∆t= 6 figure 9. temperature distribution with x-axis at the middle line of the enclosure at various angular rotation velocities for ∆t= 6 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 111 ꞷ isotherms lines( ) -50 -22 0 25 25 figure 10. temperature distribution in the enclosure at various angular rotation velocity for ∆t= 8 figure 11. temperature distribution with x-axis at the middle line of the enclosure at various angular rotation velocities for ∆t= 8 112 ahmed dhafer abdulsahib, khaled al-farhany /al-qadisiyah journal for engineering sciences 13 (2020) 099–108 ꞷ isotherms lines( ) -50 -22 0 25 25 figure 12. temperature distribution in the enclosure at various angular rotation velocity for ∆t= 10 figure 13. temperature distribution with x-axis at the middle line of the enclosure at various angular rotation velocities for ∆t= 10 article al-qadisiyah journal for engineering sciences 13 (2020) 007–012 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ghufraaneng2014@gmail.com (ghufraan mohammed aboud) https://doi.org/10.30772/qjes.v13i1.645 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. effect of polymer’s type and content on tensile strength of polymers modified asphalt mixes ghufraan mohammed aboud a*, nabil habib jassem a, teba tariq khaled a, azaldeen ali abdulhussein a, vikas kumar b a highway and transportation engineering department, mustansiriyah university, baghdad, iraq bcivil and construction engineering department, oregon state university, oregon, usa a r t i c l e i n f o article history: received 21 november 2019 received in revised form 12 january 2020 accepted 23 january 2020 keywords: asphalt mixtures polyvinyl chloride (pvc) natural rubber (nr) mechanical characteristics a b s t r a c t there has been a considerable rise in road traffic in the past twenty years due to the fast-pace development of the country. in addition, the inadequate and less frequent maintenance exacerbated the deterioration of road structure. this increase in traffic volume combined with the harsh climatic environment of iraq causes early signs of distress such as low-temperature cracking, rutting, and fatigue cracking. polymers obtained from the local sources or recycled additive from other sources have been used in pavements to improve their performance as well as to make them more sustainable. this paper presents a laboratory evaluations that were used to determine mechanical characteristics and performance of asphalt mixtures with different types of additives such as (polyvinyl chloride (pvc) and natural rubber (nr)) and various content. the modified asphalt mixtures were prepared with asphalt binder previously modified by using four percentages of polymer (2, 4, 6, and 8%) from the weight of asphalt binder. many tests were conducted to evaluate mixtures performance such as (the volumetric properties, mechanical characteristics, indirect tensile strength (its) test, and double punching shear (dps)). the results indicated that the pvc polymer and natural rubber improved the performance of the mixtures compared to the control mixture. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction over the past 20 years in iraq, the increase in road traffic with inadequate and less frequent maintenance exacerbated the deterioration of asphalt pavements. cracking and rutting are major structural distress that was led to a reduction in the serviceability of asphalt pavements. this is serving as a major problem for the local authorities and policymakers. therefore, it is important to evaluate the cracking, rutting and mechanical characteristics of the asphalt mixtures to improve its performance against rutting and fatigue cracking. therefore, sorts of additives and modifiers are employed in asphalt to reduce the distresses effect. polymers additives in asphalt pavements are a method of imparting additional durability to hma mixture, allowing to improve the pavement performance against the distresses. however, in the asphaltic pavement industry has used many additives over the past decades to improve pavement performance. a polymer commonly is one of the additives to asphalt that can improve thermal cracking and fatigue low resistance, low-temperature condition, skid resistance, and rutting resistance (( e.g. styrene-butadiene-styrene (sbs), styrene-butadiene (sb), styrene-butadiene rubber (sbr), and styrene-isoprene-styrene (sis)) and plastomers (e.g. polyethylene (pe), http://qu.edu.iq/ mailto:ghufraaneng2014@gmail.com(ghufraan https://doi.org/10.30772/qjes.v12i 8 ghufraan m. aboud et al. /al-qadisiyah journal for engineering sciences 13 (2020) 007–012 ethylene-vinyl acetate (eva), and polypropylene (pp)) [1-3]. many researchers investigated and evaluated the performance and the material design of polymer-reinforced asphalt mixture [4-6] conducted a study to study the impact of different types of polymer on rutting resistance. the results indicated that nr mixtures were most resistant from the other mixtures concerning rutting. nobinur rahman et al. [7] was used two types of additives polyethylene and pvc to evaluate asphalt properties by using marshall mix design. tests were conducted to determine voids, stability, and unit weight. the authors found that polyethylene gave a better result than pvc. polyvinyl chloride (pvc) can be used in asphalt pavements by adding them to asphalt binders by 10% and 7.5% from the total weight respectively [7]. a lot of researchers studied the evaluation and impact of plastic waste in asphalt mixtures and their performance. all results indicated that using plastic waste in asphalt mixes exhibits improvement in their engineering properties such as flow, moisture-resistance, resistance to crack propagation, and marshall stability [8-11]. [12] was focused in his study on the rheological properties of modified binders with sbs, styrenebutadiene-styrene (sbs), ground tire rubber (gtr), or polyphosphoric acid (ppa) and the results referred to the modifiers have insignificant effect at low temperatures. in addition, the results indicated that the performance of pure binder in high temperatures can be improved by adding the (pvc and nr) and other additives. 2. aim of the study in this paper, fieldwork was conducted at iraqi capital baghdad to identify the common asphalt problems and improve pavement performance. the main objectives of this study are to: (i) find the influence of different types of polymers (pvc and nr) on the performance of hot mix asphalt and mechanical characteristics. (ii) reduce cracking by obtaining softer blends. (iii) reduce rutting by reaching blends at high temperatures. (iv) increase the strength and the stability of mixtures. 3. materials and methodology 3.1. aggregates in this study, the aggregate was obtained from al-nibaee quarry close to baghdad city. its size ranges between passing sieve (19mm) and retained on sieve (4.75mm) in accordance with (s.c.r.b. 2003) [13]. two types of fine aggregates were used in this study; they were crushed aggregates and sand aggregate. the fine aggregates were range between passing the sieve (4.75mm) and retaining on the sieve (0.075mm). therefore, the aggregate gradation employed in this study was followed the middle point gradation as shown in the iraqi specification for hot mix asphalt (surface layer) and fig. 1. the aggregates properties are shown below in table 1. 3.2. bituminous materials the asphalt (40/50) penetration grade was used in this investigation; it was obtained from the daurah refinery in baghdad. the asphalt binder properties were evaluated as per the aashto routine tests. the physical properties of this grade of the asphalt binder are given in table 2. figure 1. aggregate gradation used in the study table 1. aggregate properties table 2. properties of used bituminous binder property test results penetration 43 kinematic viscosity 390 softening point 51.5 ductility > 100 flash point 335 specific gravity 1.048 loss on heat 0.18 3.3. filler portland cement bought from al-taji cement manufactory was used as filler in this work. the bulk specific gravity of the cement was 3.4 (gm/cm3). table 3 shows the ordinary portland cement filler properties. table 3. physical properties of portland cement property cement specific surface 3372 bulk sp. gr 3.4 % passing no. 200 96 3.4. additives the selection of polymer type should have durability, good adhesion, and availability. in this research, two types of polymer were selected: poly vinyl p the peak or the maximum load d diameter of the sample t height or thickness of sample 𝜎𝑡 punching shear stress 𝑝 maximum or peak load 𝑎 punch’s radius 𝑏 radius of sample. ℎ height of sample fine aggregate coarse aggregate property result astm 2010 result astm 2010 2.651 c-128 2.603 c-127 bulk specific gravity 2.692 c-128 2.658 c-127 apparent specific gravity 0.733 c-128 0.453 c-127 percent water absorption ----------18.3 c-131 loss angels abrasion 0 20 40 60 80 100 120 0.01 0.1 1 10 100 p e rc e n ta g e p a ss in g particle size (m) min limit ghufraan m. aboud et al. /al-qadisiyah journal for engineering sciences 13 (2020) 007–012 9 chloride (pvc), and natural rubber (nr). the researchers collected the polymers from the market. 3.5. marshall specimen preparation samples with a diameter (101.6 mm) and approximately (63.5 mm) height were prepared in the laboratory to study the marshall stability of asphaltic mixtures with different types and contents of additives (pvc and nr). marshall mixture design method was utilized to arrive at the optimum binder content as per iraqi specification (sorb,2003), and the methodology used for this design is astm, 2003 [14]. therefore, the weight of aggregates and mineral fillers were (1200 gm) and mixed, and the temperature mixing was near to (160°c-180°c). marshall method was utilized to design the hot asphalt mixtures. hence, the samples are required to be mixed and compacted under equivalent to the temperature corresponding to viscosities of (0.170±0.02) pas.sec and (0.280±0.03) pas.sec, respectively [15]. the rotational viscometer has been adopted for determining the viscosity of asphalt cement at temperatures (above 100c°) to ensure that the asphalt cement is adequate fluid for pumping and mixing. brookfield rheometer was used to measure the viscosity at two temperatures (135c°), and (165c°) for each asphalt binder type according to (astm d-4402 [16] and aashto t316 [17]). table 4 shows the values of mixing and compacting temperatures for the asphalt cement mixing with different percentages of additives. this study, different contents of bitumen were used to determine the optimum bitumen content for the pure bitumen, which it was (4.9%), and the o.c.a. for the additive and percent of content shown in table 5. the percentages of polymer (pvc and nr) were (2, 4, 6, and 8 %) from the weight of asphalt, which was used in this work. at (165°c) the mixing equipment and specimen molds were also placed in the oven. the number of specimens prepared in this study was 60 specimens and compacting with 75 blows on each side of the specimen. the number of specimens which was used to test the indirect tensile was (20) specimen and used (20) specimen to test the double punching as shown in fig. 2 and fig. 3. table 4. mixing and compacting temperature table 5. asphalt content and rotational viscosity (astm d4402) figure 2. shows the specimens prepared. figure 3. the specimens prepared. 4. experimental test 4.1. indirect tension strength (its) test in the investigation, tensile properties of the asphalt mixtures are determined by using the its according to astm d 6931[16]. the test gives information on tensile strength and fatigue characteristics. its test involves placing the cylindrical sample along the diametrical axis. a constant deformation rate of 5.1 cm/ min is applied to the specimens until failure by splitting along the vertical diameter at 25°c as shown in fig. 4 and fig. 5. the indirect tensile strength of each sample was determined according to the following equation: its = 2p πdt (1) where: p = the peak or the maximum load in kn d = diameter of the sample in cm t = height or thickness of sample in cm additive pvc nr mixing temp. compacting temp. mixing temp. compacting temp. 2% 163 153 161 153 4% 166 157 165 155 6% 170 161 168 159 8% 175 164 171 162 additive pvc nr o.c.a rotational viscosity at 135c° o.c.a rotational viscosity at 135c° 2% 4.9 0.14 4.9 0.132 4% 5.1 0.15 5.0 0.146 6% 5.4 0.17 5.3 0.17 8% 5.5 0.19 5.6 0.1862 10 ghufraan m. aboud et al. /al-qadisiyah journal for engineering sciences 13 (2020) 007–012 figure 4 its test loading and failure mechanism process. figure 5. specimens after its test. 4.2. double punching test this test was reported by many studies. a double punching test was used to measure the stripping of the binder from the aggregate according to jimenez [18]. conditioning of the samples was done by placing them in water bath for 30 min at 60ºc and marshall was used to prepare the samples as shown in fig. 6. the loading piston was placed on the highest associated bottom faces of the specimens and have a diameter of one in (25.4 mm) and the load was applied at a constant rate of 0.1 in. /min until failure. the tensile strength was computed by adopting the equation developed by chen [19] as follows: 𝜎𝑡 = 𝑝 𝜋(1.2𝑏ℎ−𝑎2) (2) where: 𝜎𝑡 = punching shear stress in pa 𝑝 = maximum or peak load in n. 𝑎 = punch’s radius in mm. 𝑏 = radius of sample in mm. ℎ = height of sample in mm. figure 6. specimens after double punching test. 5. results and discussion 5.1. effect of polymers and polymer content on its and punching strength the indirect tensile strength test was employed to determine the tensile properties of asphalt mixtures. the tensile properties can, in turn, be related to cracking properties of the asphalt pavement. in this study, all the asphalt specimens were tested at the same temperature to avoid any difference in their properties during their preparation or testing. therefore, the tensile test indicates the overall strength of the asphalt mixture as a response to the repetition of loads or fatigue loading. higher the strength obtained from its test, higher is the fatigue resistance of the mixture. the values of its at 25°c for the modified asphalt mixtures with the trial percentages of the polymers are presented in fig. 7. from the output of its test, the tensile strength for the control mixture is (950 kn) and these values increase with the increasing percentage of polymer until a specific percentage and then decrease. however, it can be observed that the asphalt mixture modified with (4%) of pvc polymer has the highest indirect tensile strength and with the nr has a minimum indirect tensile strength at the same percentage. at higher percentage (>4%), the tensile strength of the pvc polymer modified asphalt (pma) decreases. in addition, the indirect tensile test for the (6%) nr polymer, provide the maximum load strength and the indirect tensile test for the (6%) pvc polymer also gives an acceptable load strength and deformation. it can be said that the (6%) pvc and nr polymer content is the optimum polymer content (o.p.c) for the its test. the strength of pma in both these cases is considerably higher than the control mixture. when the polymer is added to the mixture, it is noted that the its increases more than the control mixture. this is related to the fact that polymer content gives more stiffness than the control mixture and is mainly due to the higher viscosity of asphalt binder when used polymer. on the other hands, the double punch test gives a mainly indicates the stripping behavior between binder and aggregate. double punch test results were proved that the mixtures, which contain the different percentage of polymers gives the performed well compared with the control mixture. fig.8 shows the impacted of double punching by increasing the polymers in hot asphalt mixture and concludes that the punching strength value for mixtures which contain pvc and nr are increased with the increasing percentage of polymers content. this might is related to the stiffness of mixtures, which is lower in the control mixture and higher in the pvc and nr mixtures. from the chart, it can be concluded that out of all the ghufraan m. aboud et al. /al-qadisiyah journal for engineering sciences 13 (2020) 007–012 11 additives, nr shows a drastic improvement in the punching strength of the mixtures compared to the control mixture and mixtures, which contain different percentages of (pvc). the control mixture and mixtures with (2%) and (4%) of pvc and (nr) have similar punching strength values approximately. the double punching strength with (6%) from pvc and nr give a performed well in both the tests and therefore, can be termed as the optimum polymer content (o.p.c). figure 7. indirect tensile strength for different polymer content in the mixtures. figure 8. punching strength for different polymer content in the mixtures. 5.2. effect of polymer modified asphalt on deformation the deformation results obtained from the its test for all the mixtures with different percentage of polymers are shown in fig. 9. the results correspond to the test carried out at the rate of 0.05 in/min by using the master loader device. from the results, it is evident that (2%) of pvc, modified asphalt mixture has a strength of (3963 n) for (2 mm) deformation. and this strength is comparable to the strengths of nr mixture with 4% and 6% polymer content. the ideal content from (pvc) and (nr) polymers that can improve the resistance to deformation is (6%) compared to the control mixture. because add the pvc or nr to the asphalt binder led to make the mixture hardness and that was increased with increasing the percentages of additive content which cases to reduction in the ability of the mixture to carry the load applied. therefore, all of the above due to reducing the ability to carry the deformations. (a) (b) figure 5. from a to b load-deformation relationship for different polymer content in the mixtures. 6. conclusion the principal objective of this study was to investigate the mechanical performance of modified asphalt mixtures with different types of additives (pvc and nr). the study included conducting laboratory tests on bitumen and mixtures with polymers content. also, mechanistic and simulative tests were conducted on modified and unmodified asphalt concrete mixtures (its and dpt test). after analyzing the data, the results indicated that:  the addition of pvc and nr in the asphalt mixtures led to improve the quality and strength of the asphalt mixture, it is showed by increasing the indirect tensile strength for the specimens prepared for that.  it was noted that the pvc and nr increased from the shear resistance among asphalt binder and aggregates and that may be related to increasing the stiffness of the asphalt mixture. 0 100 200 300 400 500 600 no additive 2 4 6 8 m a x . lo a d ( k n ) % polymer content control nr pvc 0 100 200 300 400 500 600 no additive 2 4 6 8 m a x . lo a d ( k n ) % polymer content control nr pvc 0 2000 4000 6000 0 1 2 3 4 lo a d ( n ) deformation (mm) control 2% pvc 4 % pvc 6 % pvc 8 % pvc 0 2000 4000 6000 0 1 2 3 4 lo a d ( n ) deformation (mm) control 2 % nr 4 % nr 6 % nr 8 % nr 12 ghufraan m. aboud et al. /al-qadisiyah journal for engineering sciences 13 (2020) 007–012  the asphalt mixtures with the polymer-modified asphalt proven adequate to cracking resistance.  the optimum polymer content between all the different percentage of polymers used in this experiment (2%, 4%, 6% and 8%) in the asphalt mixture from (pvc) and (nr) is the (6%).  the ideal content of polymers from (pvc) and (nr) that can improve from the resistance to deformation is (6%) compared to the control mix i.e. hma mix without polymers. acknowledgment the authors would like to express their deepest gratitude to mustansiriyah university for providing support, and also to the transportation and highway engineering department at almustansiriyah university for the technical support for this study. references [1] j. zhu, b. birgisson, n.j.e.p.j. kringos, polymer modification of bitumen: advances and challenges, 54 (2014) 18-38. [2] j.-s. chen, m.-c. liao, h.-h.j.p.f.a. tsai, evaluation and optimization of the engineering properties of polymer-modified asphalt, 2(3) (2002) 75-83. [3] y.j.c. yildirim, b. materials, polymer modified asphalt binders, 21(1) (2007) 6672. [4] s. tayfur, h. ozen, a.j.c. aksoy, b. materials, investigation of rutting performance of asphalt mixtures containing polymer modifiers, 21(2) (2007) 328-337. [5] g.j.j.o.m.s. airey, styrene butadiene styrene polymer modification of road bitumens, 39(3) (2004) 951-959. [6] m.r.s. fernandes, m.m.c. forte, l.f.m.j.m.r. leite, rheological evaluation of polymer-modified asphalt binders, 11(3) (2008) 381-386. [7] m.n. rahman, m. ahmeduzzaman, m. sobhan, t.j.a.j.o.c.e. ahmed, architecture, performance evaluation of waste polyethylene and pvc on hot asphalt mixtures, 1(5) (2013) 97-102. [8] v. swami, a. jirge, k. patil, s. patil, s. patil, k.j.i.j.o.e.s. salokhe, technology, use of waste plastic in construction of bituminous road, 4(5) (2012). [9] a.m. abu abdo, m.e. khater, enhancing rutting resistance of asphalt binder by adding plastic waste, cogent engineering, 5(1) (2018). [10] m.a.j.j.i.j.o.a.o.i.i.e. chavan, management, use of plastic waste in flexible pavements, 2(4) (2013) 540-552. [11] a. gawandea, g. zamarea, v. rengea, s. taydea, g. bharsakaleb, an overview on waste plastic utilization in asphalting of roads. [12] a. behnood, j.j.c. olek, b. materials, rheological properties of asphalt binders modified with styrene-butadiene-styrene (sbs), ground tire rubber (gtr), or polyphosphoric acid (ppa), 151 (2017) 464-478. [13] s.c.r.b. , iraqi general specifications for roads & bridges 2003 2003. [14] a. astm, standard test method for resistance to plastic flow of bituminous mixtures using marshall apparatus, (2000). [15] s.m.j.a.i. design, lexington, ky, superpave series no. 2 (sp-2), (1996). [16] d. astm, standard test method for viscosity determination of asphalt at elevated temperatures using a rotational viscometer, in: american society for testing and materials, 2015. [17] a.a.o.s. highway, t. officials, standard specifications for transportation materials and methods of sampling and testing and aashto provisional standards, american association of state highway and transportation officials, 2016. [18] r. jimenez, testing for debonding of asphalt from aggregates, (1973). [19] w. chen, double punch test for tensile strength of concrete, sept. 1969 (70-18) pb224770/as (ntis), (1969). article al-qadisiyah journal for engineering sciences 13 (2020) 080–090 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ammarabdulkadhim@mustaqbal-college.edu.iq (ammar abdulkadhim) https://doi.org/10.30772/qjes.v13i2.633 2411-7773/©2020 university of al-qadisiyah. all rights reserved. comprehensive review of natural convection heat transfer in annulus complex enclosures ammar abdulkadhim a*, khaled al-farhany b, azher m. abed a, hasan sh. majdi c a air conditioning and refrigeration techniques engineering department, al-mustaqbal university college, babylon, 51001, iraq b department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq. c department of chemical engineering and petroleum industries, al-mustaqbal university college, babylon, 51001, iraq a r t i c l e i n f o article history: received 01 march 2020 received in revised form 26 april 2020 accepted 30 april 2020 keywords: natural convection complex enclosures triangular trapezoidal parallelogrammic rhombic elliptical a b s t r a c t the natural convection heat transfer has many applications in engineering like solar collectors, cooling of electronic equipment, and geothermal engineering. the present work demonstrates the recent publications in the last ten years in this specific subject for a body located in complex shapes like rhombic, wavy, trapezoidal, elliptical, and parallelogrammic enclosure. many parameters like ra, nu, number of undulations, the position of the inner body had been addressed and discussed to draw the main conclusions and recommendations. it is worthy to mention that a wavy enclosure has been investigated less than the other simple enclosure shapes due to its complexity. besides that entropy generation should be included in future studies in complex shapes of enclosure as this will helps the researchers to extend their studies. the inner bodies inside trapezoidal, parallelogrammic enclosure are very limited, and more investigation should be done. the review concluded for the different shapes of enclosure with the tables that illustrate the major finding of each study. finally, the governing equations of the natural convection of enclosure filled with pure fluid, porous medium, and nanofluid had been addressed. © 2020 university of al-qadisiyah. all rights reserved. 1. simple enclosures the natural convection heat transfer in simple enclosure shapes as illustrated in fig. 1 had been studied numerically by various researchers due to its importance in energy related applications. some of these studies were [1-20]. ghasemi et al. [2] investigated numerically the influence of the magnetic field on buoyancy driven fluid flow in a square nanofluid enclosure filled with al2o3-water. the results indicated that rayleigh and hartmann number had an opposite influence on heat transfer while the increasing of nanoparticle loading helps in augmentation of heat transfer. another important study focus on using a different model of nanofluid properties presented by lai and yang [3] using lattice-boltzmann scheme. they found that different methods of nanofluid properties affect the nusselt number value. bhuvaneswari et al. [4] computed using a finite volume approach the natural convection with the magnetic field in a square enclosure. the major of this study is that the authors applied sinusoidal temperature distribution to both of the sidewalls and keeping the horizontal wall adiabatic. the results indicated that increasing hartmann number http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i file:///d:/00%20mechanical%20department/00%20مجلة%20القادسية/رفع%20اعداد/اعداد%202020/العدد%20الثاني%20المجلد%2013/2%20عمار%20+%20خالد/81-.docx%23top%20of%20the%20document abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 81 reduces the heat transfer. alam et al. [5] demonstrated the impact of aspect ratio and heat source power density on fluid flow circulation and heat transfer of free convection within rectangular enclosure heated and cooled partially from the vertical walls while the rest of them and others walls maintained adiabatic. they found that increases the aspect ratio augmented the heat transfer and it reaches its maximum value at aspect ratio equals to one. [6, 7] illustrated the double diffusive natural convection in tilted rectangular enclosure including the impact of a magnetic field and heat source. they concluded that heat source had a crucial impact on heat transfer. for more details about the previous works, the reader can be referring to [8-15]. wang et al. [16] presented a comparison between the impact of al2o3-h2o and ga-h2o and the radius under different rayleigh numbers of heat transfer using a two-phase lattice boltzmann method. the authors deduced that ga-h2o enhances the heat transfer better than al2o3h2o. al-farhany and abdulkadhim [17] examined the conjugate problem in a square enclosure filled with porous media under various rayleigh and darcy numbers and they obtained that wall thickness effects on the transformation of the heat mode from convection into conduction which reduces the heat transfer. barik and al-farhany [21] studied the inflleucne of inclined baffle in nanofluid/porous square enclosure using comsol. dutta et al. [18] studied the entropy generation in quadrant porous enclosure heated sinusoidally from its bottom wall. they concluded that entropy generation due to fluid friction is dominated at high values of darcy number while they noticed the entropy formed due to heat transfer is the major influencer on low darcy number. torki and etesami [19] experimentally studied the natural convection of a rectangular enclosure filled with sio2 at different nanofluid loading and enclosure inclination angles. they obtained that the nanofluid did not affect low concentration value and the inclination angle of a rectangular enclosure had a strong effect. in addition, the nusselt number is increased as the inclination angle goes up. graževičius et al. [20] studied experimentally and numerically using ansys 17.2 of natural convection for removing heat from the reactor using a passive system. also, the natural convection in complex shapes had been reported by various researchers like [22-25]. figure 1. schematic diagram of simple shape of enclosure (square) [2] sheikholeslami and chamkha [22] examined the free convection in a liddriven enclosure filled with fe3o4 with applied magnetic field and wavy wall. they obtained that increasing magnetic number, rayleigh number, and nanofluid volume fraction increases the nusselt number while hartmann number had a reverse impact on nusselt number. sheikholeslami [23] studied the liquid metal due to natural convection in a wavy enclosure for various values of rayleigh number, amplitude of wavy wall, and hartmann number. it is worthy to mention here that the last parameters increasing lead to reduce the nusselt number. two important studies collect between mhd and wavy enclosure is presented in [24, 25] and they agreed with the previous mentioned results in the previous works of various researchers. besides that, various researchers dealt with the different shapes of an inner body located inside a regular simple enclosure shape like a square or rectangle that had been presented in fig. 2. the inner body located within the enclosure had a wide range of applications like a solar collector, fuel cell, etc. the researchers among the world interested in understanding the effect of inner shapes like circular, triangular, elliptical, and wavy inside different shapes of the enclosure. other researchers focus on the position of the inner body and change the direction vertically, horizontally and longitudinally. these are the main parameters that affect the heat transfer so that some of these studies are presented by [26-31]. lee et al. [26] used an immersed boundary method to examine the changing of an inner cylinder located within square enclosure horizontally and longitudinally while another study by [27, 28] illustrates the vertical position on heat transfer. ali et al. [29] studied the mixed convection due to rotating inner circular cylinder within square enclosure filled with air using ansys fluent. roslan et al. [30] studied the heated circular cylinder located within the cold enclosure. the main important thing in this study is that the inner circular cylinder had sinusoidal temperature under unsteady conditions. we summarized the previous publications regarding the natural convection within simple shape, complex shapes and simple annulus enclosure in table 13, respectively. finally, the present work concentrates on the inner body located inside the non-square enclosure. figure 2. schematic diagram of the inner body within simple enclosure shape [27] 82 abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 table 1 summarized the studies of natural convection inside a simple shape of enclosure ref objective enclosure shape software/model used conclusions special findings ghasemi et al. [2] mhd and nanofluid effect square cvm using simple algorithm hartmann and rayleigh numbers had an inverse effect on nusselt number nanofluid effect may increases of decreases nusselt number depending upon rayleigh number lai and yang [3] al2o3 nanofluid square lattice – boltzmann method (lbm) nanofluid thermophysical models effect on the computation of the nusselt number lbm is recommended for the practical engineering applications bhuvaneswari et al. [4] sinusoidal temperature boundary conditions with mhd effect square fvm increasing hartmann number reduces the heat transfer the phase deviation of applied sinusoidal temperature effect on nusselt number alam et al [5] partial cooling/heating and aspect ratio rectangle fem nussselt number increases when the aspect ratio range from 0.5 – 10 beyond this value it reduces nu as it goes up. the maximum nusselt number is achieved at aspect ratio equals to one. teamah et al. [6] double diffusive, inclinations angle, mhd, buoyancy ratio inclined rectangle cvm simpler algorithm lowest and highest value of sherwood and nu numbers were at 75 and 150 sherwood number is not affected by heat absorption and generation. el qarnia et al. [9] phase change due to melting rectangle fvm/fortran two correlations had been developed. the developed model can be used in phase change material nithyadevi et al. [15] effect of numbers of discrete heater, prandtl number and heat generation rectangle fvm increasing numbers of heater and prandtl number enhance the heat transfer increasing heat generation reduces the heat transfer qi at a;. [16] ra and nanofluid radius rectangle two-phase lbm small radius of nanofluid can enhance better than the big size the augmentation of nanofluid is better at low ra number al-farhany and abdulkadhim [17] conjugate problem in porous medium square fem/comsol increasing ra and da enhance the heat transfer increasing the conduction wall reduces the heat transfer dutta et al. [18] porous media, entropy generation with nonuniform bottom wall temperature quadrant fem increasing ra and da increase the heat transfer as mentioned in most of the publications when the darcy number is low, the heat transfer's entropy generation is higher while at the high da, the entropy generation due to friction of fluids is higher torki et al. [19] nanofluid, inclined enclosure rectangle experimental study increasing rayleigh number increases nu inclination effect is higher at low nanofluid loading table 2 summarized the studies of natural convection inside the complex shape of enclosure ref objective enclosure shape software/model used conclusions special findings sheikholeslami et al. [22] mhd, lid-driven cavity, ferro nanofluid wavy fem/fortran increasing nanofluid loading, rayleigh, and magnetic numbers increases the heat transfer while hartmann increases to reduce it. the authors studied the wavy top wall which is a little bit make a difference with the previous publications sheikholeslami et al. [23] mhd wavy cvfem increasing hartmann number reduces nu hartmann number is highly effects on fluid flow and heat transfer xiong, et al. [25] nanofluid/porous layers and mhd wavy cvfem ha increasing leads to reduction in the nusselt number increasing da leads to an improvement in the heat transfer abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 83 table 3 summarized the studies of natural convection between inner body within regular (simple) enclosure shapes ref objective enclosure shape software/model used conclusions special findings lee et al. [26] position of inner circular cylinder in horizontal and diagonal direction circular cylinder within square enclosure fvm increasing ra number leads to enhance the nusselt number it is noted that when the cylinder becomes closest to the corner or left walls, the eddies that located in the direction of the cylinder will be separated while one large eddies formed behind the cylinder hussain and husssein [27] vertical position of the inner cylinder, constant heat flux is considered for the cylinder circular cylinder within square enclosure fvm as ra increases, nu goes up when the cylinder moves vertically upward, two inner cells (eddies) are formed below it. park et al. [28] same the study of [27] except they applied isotherm hot temperature to the cylinder [30] and [31] unsteady case study wavy temperature conditions inside a square cavity comsol increasing the oscillation of the heat source leads to improve the heat transfer. the frequency of wavy condition 25π – 30π augments the heat transfer better 2. triangular enclosure this section describes different shapes of an inner body located inside a triangular enclosure. schematic diagram of this case study is illustrated below in fig. 3. some of these studies presented by [32-38]. figure 3. schematic diagram of the inner body in a triangular enclosure [32] xu et al. [32] examined numerically the natural convection heat transfer between various shapes of the inner cylinder (circular, square, rhombic, and triangular) located inside the triangular enclosure tilted for various inclination angle. the inner cylinder is kept at uniform hot temperature while the triangular enclosure is cold. the governing equations had been solved numerically using a finite volume method and validated with the previously published work along the bottom wall. the results are crucial and indicate that increasing the rayleigh numbers breaking down the symmetry of streamlines contours and concentrates the isotherms contours to the top between the gaps. yu et al. [33] examined the influence of various values of prandtl number on heat transfer between a circular cylinder located inside an inclined triangular enclosure. the equations of mass, energy, and momentum of fluid along with boussinesq approximations had been solved using a finite volume scheme. the results indicate that a low prandtl number less than 0.7 had no effect of fluid flow intensity and heat transfer while the inclination angle had strong effect on it. the authors proposed important empirical equations of nusselt number in terms of prandtl number. selimefendigil and öztop [34] examined the mixed convection between circular cylinder within right-angled triangular enclosure heated partially from its left vertical wall. the governing equations had been solved numerically using a finite element method. the results are important because of increasing hartmann number reduces both of entropy generation and heat transfer while increasing nanofluid volume fraction and speed of rotating circular cylinder increases both of them. yu et al. [35] studied the unsteady free convection between circular cylinder within triangular enclosure under various effects of grashof number, aspect ratio (inner diameter), and inclination angle. they simulated this phenomenon using cfd code ansys fluent 6.3 which is based upon a finite volume method. they developed a relation between nusselt number as a function of grashof number for different inner cylinder diameters and inclination angles. wang et al. [36] examined the mixed convection within the different sizes of an inner rotating circular cylinder located within a triangular enclosure and the gap between them was filled with ethylene glycol-silicon carbide nanofluid for different rayleigh numbers. fluent cfd code had been used to simulate the whole of this problem. the results of this paper agreed with the previously published works. sourtiji et al. [37] examined the natural fluid flow between a circular cylinder within a triangular nanofluid enclosure using a control volume based on a finite element scheme. the nanofluid thermal thermo-physical properties like viscosity and thermal conductivity had been predicted using brinkman and maxwell-garnetts. it is obtained that adding void fraction of nanofluid had a remarkable impact at low rayleigh numbers. also, it had been observed that increasing inner circular cylinder diameter augments the heat transfer obviously. another important investigation had been reported in amrani et al. [38]. the authors studied the combined effect of radiation as well as free convective flow for triangular enclosure within rectangular body. as the most of researchers, finite volume method had been used to simulate this phenomenon under various rayleigh numbers and aspect ratios. 3. trapezoidal this section summarized the convection heat transfer due to the density difference between the inner body located within the trapezoidal enclosure [39-43]. schematic representation of this case is presented in fig. 4. 84 abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 figure 4. schematic diagram of the inner body in a triangular enclosure [39] hussein et al. [39] investigated numerically the mixed convection heat transfer between the inner circular rotating cylinder immersed in the trapezoidal enclosure using comsol which is based upon the finite element scheme. the gap between the inner body and the enclosure is divided into two layers system; the upper layer is filled with copper-water nanofluid while the lower layer is consisting of the same nanofluid immersed in a saturated porous medium. the authors studied the influences of many dimensionless parameters such as rayleigh and darcy numbers, nanofluid void fraction as well as many geometrical parameters such as undulations number of a bottom wavy wall, inner body's diameter and rotational speed and the thickness of the porous layer. the results were crucial and indicated that the increasing of rayleigh, darcy numbers, nanofluid void fraction, and inner body's diameter rotational leads to augmentation in the local nusselt number, and that means enhancement of the heat transfer. however the behavior of other parameters is inverse which means as the layer of the porous medium and the number of undulations goes up, the heat transfer is reduced. esam et al. [40] examined the natural convection heat transfer in a trapezoidal enclosure filled with multilayers using the finite element method. the enclosure is partially heated from the bottom wall while the top wall is kept at isotherm cold temperature. the two inclined walls, as well as the inner circular cylinder and the rest length of the bottom wall, are assumed adiabatic. the upper layer is filled with ag-water nanofluid, while the lower layer filled with porous media saturated with the same nanofluid. the results had been validated with the previously published works and the agreement was good. the results indicate that increasing nanofluid, darcy, and rayleigh numbers increases the fluid flow intensity and the heat transfer rate. however, the behavior of porous layer thickness is completely reversed. khan et al. [41] explained the mixed convection heat transfer between the inner heated circular cylinder rotating counter-clockwise located in a trapezoidal enclosure. the trapezoidal enclosure is kept adiabatic at its top and bottom wall while the two inclined walls are kept at cold temperatures. they made a comparison between the influence of the rotating cylinder and a motionless cylinder in a square enclosure. their results confirmed that the rotating cylinder as well as the inclination angle of the sidewall effect significantly on the heat transfer. selimefendigil [42] demonstrated numerically the natural convection between different shapes of the inner conductive body within a trapezoidal enclosure filled with different shapes of nanoparticle (blade, spherical, and cylindrical). the top and bottom walls are adiabatic while the left and right vertical walls are kept at isotherm hot and cold temperature respectively. the authors used finite element scheme to solve the governing equations and the validation seems good. the parameters of this study were rayleigh number, thermal conductivity ratio, solid volume fraction, shapes of the nanoparticle and the inclination angle. it is worthy to mention that they conclude the shape of nanoparticle change obviously the heat transfer and the cylindrical shape is recommended for better nusselt number and better enhancement in heat transfer. ahmed et al. [43] visualized numerically using finite element techniques the heat lines in a nanofluid trapezoidal enclosure separated by a porous divider. the top wall is kept cold while a non-uniform temperature profile is applied to the bottom wall. the side walls are adiabatic. the parameters of this study are rayleigh and darcy number as well as nanofluid volume fraction as physical parameters. also, many geometrical parameters had been investigated such as porous layer thickness and its positions as the authors moved it vertically upwards and downwards. the major findings were increasing the thickness of porous divider with the rayleigh numbers augments the heat transfer. also, the position of the porous divider is significant at low rayleigh number while at higher rayleigh number, the nusselt number will be at the minimum values when the divider moved vertically downward. we summarized the studies of the inner body within triangular and trapezoidal enclosure in table 4. table 4 summarized the studies of natural convection between inner body within a triangular and trapezoidal enclosure ref objective enclosure shape software/ model used conclusions special findings xu et al. [32] laminar free convection, effect of ra, aspect ratio and inclination angle cylinder inside triangular enclosure cvm at constant aspect ratio, the inclination angle and ra effect significantly on nusselt number. correlation of nusselt number as a function of ra for each value of aspect ratio yu et al. [31] effect of prandtl number cylinder inside coaxial triangular fvm inclination angle had a strong impact on nu unique effect of low prandtl number nu while when pr≥0.7 it does not affect nu selimefendigil and öztop [34] mixed convection, mhd, nanofluid, entropy rotating insulated cylinder inside triangular enclosure fem increasing nanofluid concentrations and rotating lead to an increasing in total entropy and nusselt number hartmann number increasing leads to a reduction in both the entropy and nusselt number yu et al. [35] unsteady natural convection cylinder inside coaxial triangular ansys fluent correlations of nusselt number had been developed. nusselt number history had been presented wang et al. wang et al. [36] mixed convection, nanofluid cylinder inside coaxial triangular ansys fluent increasing ra and nanofluid volume fraction improve the nu rotational velocity effect significantly on nu abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 85 sourtiji et al. [37] laminar buoyancy driven flow, nanofluid cylinder inside triangular enclosure cvfem nanoparticle improve the heat as mentioned in most of the studies maxwell–garnetts (mg) and brinkman models had been used to simulate the nanofluid presence amrani et al. [38] radiation and natural convection effect rectangle inside triangular enclosure fvm decreasing the aspect ratio and increasing the ra number enhances the heat transfer thermal radiation promotes the heat transfer hussein et al. [39] mixed convection with multi-layer system rotating cylinder in trapezoidal enclosure with sinusoidal bottom wall fem the increasing the size and the rotation speed of the inner cylinder in addition to increases the da, r and nanofluid loading will improve the heat transfer increasing porous thickness and number of undulation of the bottom wall reduce the heat transfer esam et al. [40] free convection with multi-layer system fixed adiabatic cylinder within trapezoidal enclosure fem the results indicate that increasing ra, da and nanofluid loading enhance the heat transfer increasing porous thickness reduces the heat transfer khan et al. [41] mixed convection, air rotating cylinder in trapezoidal enclosure fem grashof number for large inclination angle is very strong rotating speed of the inner cylinder and inclination angle of the trapezoidal wall effect highly on the nusselt number selimefendigil [42] natural convection with different shapes of nanoparticles (blades, spherical and cylindrical) different shapes of inner body inside trapezoidal fem effect of ra, thermal conductivity ratio, nanofluid loading and shapes of nanoparticle on nu had been discussed cylindrical nanoparticle gives better performance ahmed et al. [43] visualization of heatlines of free convection trapezoidal enclosure divided by porous medium partition fem increasing ra, nanofluid volume fraction and darcy number augments the heat transfer porous position equals to 0.5 gives the better heat transfer 4. parallelogrammic this section summarized the convection heat transfer due to the density difference between the inner body located within the parallelogrammic enclosure [44-48]. the computational domain of these shapes is inserted in fig. 5. hussein [44] investigated numerically the influence of the position of an inner circular cylinder located inside a parallelogrammic enclosure filled with air using a finite volume method. the inner circular cylinder is kept at a hot temperature while both vertical walls are cold. the top and bottom walls are adiabatic. the effect of rayleigh number, the inclination angle of the vertical wall, and the inner circular cylinder position had been taken into account and examined their effect on fluid flow strength and the heat transfer. it was obtained that the maximum flow strength will be when the inclination angle is zero i.e., for square enclosure when the cylinder moves upwards by +0.1. it was also obtained that when the cylinder moves downward will have greater nusselt number than moving upwards. majdi et al. [45] examined the natural convection between the hot circular cylinder immersed in a nanofluid parallelogrammic enclosure. the finite element had been used to solve the governing equations of heat transfer and fluid flow numerically. the validation was in good agreement with the previous publishing works. the results indicated that the increase of nanofluid volume fraction and rayleigh number enhances the heat transfer especially if the inner circular cylinder moves vertically downwards until it reaches 0.1. chamkha [46] examined numerically the conjugate (conductive-natural and forced) convection within the parallelogrammic enclosure separated by solid partition using the finite volume method. the influence of various parameters such as richardson number, the inclination angle of the enclosure from the cavity left vertical wall as well as the thermal conductivity ratio. the results were crucial and all of the mentioned parameters affect the heat transfer rate. baïri [47] used a finite volume scheme to simulate free convection under transient conditions within a parallelogrammic enclosure filled with air. the enclosure is partially heated from its left vertical wall while cold temperature conditions are applied to the right wall. the top and bottom walls are kept adiabatic. hussain et al. [48] simulated the free convection in a parallelogrammic enclosure containing a volumetric source under various inclination angles. the enclosure is heated non-uniformly from its left wall while the right wall is at isotherm cold temperature. the top and bottom walls are adiabatic. figure 5. schematic diagram of the inner body in a parallelogrammic enclosure [45] 5. rhombic this section summarized the convection heat transfer due to the density difference between the inner body located within rhombic enclosure [4953]. the present case is illustrated in fig. 6. anandalakshmi and basak [49] examined numerically the entropy generation and natural convection in a rhombic enclosure filled with saturated porous medium for different heating situation and inclination angle. different uniform temperatures applied on the bottom and top walls where the bottom wall is warmer. adiabatic conditions are considered to 86 abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 both inclined vertical walls. the finite element scheme had been used to solve the continuity, momentum, and energy equations. choi et al. [50] demonstrated the position of an inner circular cylinder located within the rhombic enclosure subjected to transient conditions using the immersed boundary scheme. the simulation of this study was done under various dimensionless parameters, which are rayleigh number and inner cylinder locations, which is changed vertically upwards and downwards. the results indicated that when the cylinder moves up, two circulations formed below it, and the rayleigh number had a significant effect on the maps of streamlines and isotherms. another important study was presented by hosseinjani and nikfar [51] focused on the natural convective fluid flow between two horizontal circular cylinders located within the nanofluid rhombic enclosure. the impact of symmetry, asymmetry, instability, and stability of cu-o nanofluid under various rayleigh numbers had been explained. the impact of other parameters had been included such as diameter and the distance of inner cylinder, nanoparticle void fraction. the results reported that increasing the distance leads to an increase in transient asymmetric flow. dogonchi et al. [53] investigated numerically the natural convection between the circular cylinder within a partially heated rhombic enclosure using cvfem. the influence of nanoparticle shape factor, nanoparticle volume fraction, and had been examined. it is obtained the platelet shape had a better heat transfer rate. the studies of the inner body within parallelogrammic and rhombic enclosure have been summarized in table 5. figure 6. schematic diagram of the inner body in a rhombus enclosure [50] table 5 summarized the studies of natural convection between inner body within parallelogrammic and rhombic enclosure ref objective enclosure shape software/ model used conclusions special findings hussein [44] natural convection in parallelogrammic enclosure for different vertical locations cylinder inside parallelogrammic enclosure filled with air fvm increasing ra leads to enhance the heat transfer and increases the fluid flow strength. in addition, it is recommended to incline the vertical wall 15 for better fluid strength. for better fluid flow strength and heat transfer rate, it is recommended to move the inner cylinder towards the bottom wall vertically majdi et al. [45] natural convection in parallelogrammic enclosure for different vertical locations cylinder inside parallelogrammic enclosure filled with nanofluid fem ra and nanofluid enhance the heat transfer and fluid flow strength increasing inclination angle enhances the heat transfer chamkha [46] mixed convection parallelogrammic with solid partition fvm the thermal conductivity ratio, ri number, inclination angle and the direction of movement of the left vertical wall upward and downward effect on heat transfer and fluid dynamics mean skin friction coefficient when the wall moves downward was higher than if it moves upward baïri [47] unsteady buoyancy in buildings parallelogrammic enclosure filled with air fvm the influence of ra number and the slop of the building effect on the building cooling the authors presented data for analysis of building including fluid flow and heat transfer hussain et al. [48] free convection, heat source with nonuniform left sidewall parallelogrammic enclosure filled with air fvm internal and external rayleigh number effect on heat transfer. increases inclination angle in positive direction leads to a reduction in fluid flow strength while when it increases in the negative direction; the fluid flow circulation becomes larger. anandalakshmi and basak [49] free convective flow with entropy generation with two different locations (cases) of the heat sources rhombic filled with porous medium fem rhombic with inclination angle 30 is recommended to usage as it gives minimum entropy generation. however, it gives less heat transfer enhancement case 1 is better in energy efficiency compared to case 2 as the latter produces much irreversibility more than case 1 abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 87 choi et al. [50] impact of inner position of circular cylinder on heat transfer under transient state. rhombus with internal cylinder fvm increasing ra number leads to an augmentation in nu it is obtained that minimum nu is obtained when the cylinder moved upward. it is recommended to move downward for better heat transfer hosseinjani and nikfar [51] unsteady free convection two-cylinder inside rhombic enclosure immersed boundary scheme at low ra, the nanofluid had a negligible effect on nu. while at high ra, nu id highly effected. the horizontal distance between the circles effect on the instability of the fluid flow dogonchi et al. [53] nanoparticle shape (platelet, cylindrical and spherical) effect on heat transfer cylinder in partially thermal active zone of rhombus cvfem rayleigh number and nanofluid increasing helped in improving nu platelet shape gives better performance 6. elliptical this section summarized the convection heat transfer due to the density difference between the inner body located within the elliptical enclosure [54-58] as shown in fig. 7. sheikholeslami et al. [54] examined the natural convection between the inner elliptical body within a circular cylinder enclosure filled with nanofluid. the results explained that increasing rayleigh number, nanoparticle, and inclination angle leads to an increase in the nusselt number. zhang et al. [55] investigated the natural convection between the hot elliptical inner body inside the cold square enclosure using a variational multiscale element scheme. the parameters were the major axis of the inner ellipse, rayleigh number, and the inclination angle of the square enclosure. the results confirmed that inner body size, as well as the angle of inclination, had a noticeable impact on fluid flow. sheikholeslami et al. [56] examined free convection, thermal radiation as well as a magnetic field between elliptical inner body within elliptical enclosure filled with nanofluid. kefayati and tang [57] examined numerically the inner cylinder or/and elliptical inner body inside a square enclosure by the lattice boltzmann method. abdulkadhim [58] demonstrated the free convection heat transfer within the elliptical enclosure with an inner circular cylinder. the gap was filled with nanofluid. the influence of the magnetic field, rayleigh number, heat coefficient had been examined and addressed. figure 7. schematic diagram of the inner body in an elliptical enclosure [56] 7. wavy enclosure this section summarized the convection heat transfer due to the density difference between the inner body located within wavy enclosure [24, 52, 58-62]. as an illustrative example for this case is indicated in fig. 8. figure 8. schematic diagram of the inner body in an elliptical enclosure [62] one of the interesting investigation that presented by dogonchi [52] which concluded the inner rhombic body within wavy enclosure filled with fe3o4. control volume based upon the finite element method had been used in the simulation. magnetic field dependent upon new viscosity model is employed. many parameters had been included in the study like rayleigh and hartmann number, radiation parameters, aspect ratio, and nanoparticle shape factor (platelet, cylindrical, and spherical). the results highlighted that the increase of aspect ratio when the hartmann number remains constant will reduce the rate of heat transfer. jabbar et al. [59] examined the wavy interface on heat transfer between square enclosure divided into two layers, nanofluid/porous layer as well as a non-newtonian layer for various undulation number of wavy and rayleigh numbers. hatami and safari [60] used the finite element method to solve the free convection between the circular cylinder inside the wavy nanofluid enclosure. boulahia et al. [61] modeled the inner hot and cold cylinders inside the wavy enclosure. abdulkadhim et al. [62] illustrated the multilayer system between the wavy inner cylinder within a wavy enclosure using a finite element scheme under various inner cylinder location and different undulations numbers. it can be seen in table 6 which summarized the studies of elliptical and wavy enclosure with the internal body. 88 abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 table 6 summarized the studies of natural convection between inner body within elliptical and wavy enclosure ref objective enclosure shape software/ model used conclusions special findings sheikholeslam i et al. [54] natural convection with nanofluid circular enclosure with inner elliptical body cvfem increasing of nanofluid loading, rayleigh number and inclination angle increases the nusselt number increasing ra reduces the enhancement of heat transfer. zhang et al. [55] natural convection elliptical body inside tilted square enclosure fem the size of inner ellipse, as well as ra, is highly affected on nu the effect of inclination angle is small on nu sheikholeslam i et al. [56] natural convective flow, mhd, nanofluid elliptical enclosure with internal elliptical body cvfem increasing of the inclination angle of the inner elliptical body increases the heat transfer rate derivation of formula of nu kefayati and tang [57] natural convection circle and elliptical inner body inside square enclosure lbm increasing the size of cylinder augments the heat transfer as bingham number goes up, heat transfer goes down abdulkadhim [58] natural convection, mhd, heat generation/absorption and nanofluid circular body in a nanofluid elliptical enclosure fem hartmann number and ra had an inverse effect on nu the change of inner cylinder horizontally effect on the heat transfer characteristics jabbar et al. [59] free convection with wavy wall square enclosure with wavy wall fem nu decreases as the power index increases thickness layer effect on nu hatami and safari [60] natural convection and nanofluid internal cylinder inside wavy enclosure fem the location of inner cylinder effect on heat transfer the central location gives better heat transfer characteristics boulahia et al. [61] natural convection cylinder inside wavy enclosure fvm ra and nanofluid increasing leads to increases the heat transfer increasing number of undulations and reduction in the amplitude of the wavy surface leads to augmentation in heat transfer abdulkadhim et al. [62] natural convection with multilayer system wavy internal body within wavy enclosure comsol number of corrugated effect are small the inner body position effect on heat and fluid flow 8. governing equation finally, it is important to insert the governing equations used in this specific subject of natural convection heat transfer within enclosure filled with pure fluid, porous medium, and nanofluid [63]. 8.1. pure fluid 𝜕𝑈 𝜕𝑋 + 𝜕𝑉 𝜕𝑌 = 0 (1) 𝑈 𝜕𝑈 𝜕𝑋 + 𝑉 𝜕𝑈 𝜕𝑌 = − 𝜕𝑃 𝜕𝑋 + 𝑃𝑟( 𝜕2𝑈 𝜕𝑋2 + 𝜕2𝑈 𝜕𝑌2 ) (2) 𝑈 𝜕𝑉 𝜕𝑋 + 𝑉 𝜕𝑉 𝜕𝑌 = − 𝜕𝑃 𝜕𝑌 + 𝑃𝑟 ( 𝜕2𝑉 𝜕𝑋2 + 𝜕2𝑉 𝜕𝑌2 ) + 𝑅𝑎𝑃𝑟𝜃 (3) 𝑈 𝜕𝜃 𝜕𝑋 + 𝑉 𝜕𝜃 𝜕𝑌 = 𝜕2𝜃 𝜕𝑋2 + 𝜕2𝜃 𝜕𝑌2 (40 8.2. porous medium 𝜕𝑈 𝜕𝑋 + 𝜕𝑉 𝜕𝑌 = 0 (5) 𝜕𝑈 𝜕𝑌 = − 𝐾 𝜇 𝜕2𝑃 𝜕𝑋 𝜕𝑌 (6) 𝜕𝑉 𝜕𝑋 = − 𝐾 𝜇 𝜕2𝑃 𝜕𝑋 𝜕𝑌 + 𝑅𝑎 𝜕𝑇 𝜕𝑋 (7) 𝑈 𝜕𝜃 𝜕𝑋 + 𝑉 𝜕𝜃 𝜕𝑌 = 𝜕2𝜃 𝜕𝑋2 + 𝜕2𝜃 𝜕𝑌2 (8) 8.3. nanofluid 𝜕𝑈 𝜕𝑋 + 𝜕𝑉 𝜕𝑌 = 0 (9) 𝜌𝑛𝑓 (𝑈 𝜕𝑈 𝜕𝑋 + 𝑉 𝜕𝑈 𝜕𝑌 ) = − 𝜕𝑃 𝜕𝑋 + 𝜇𝑛𝑓 ( 𝜕2𝑈 𝜕𝑋2 + 𝜕2𝑈 𝜕𝑌2 ) (10) 𝜌𝑛𝑓 (𝑈 𝜕𝑈 𝜕𝑋 + 𝑉 𝜕𝑈 𝜕𝑌 ) = − 𝜕𝑃 𝜕𝑌 + 𝜇𝑛𝑓 ( 𝜕2𝑉 𝜕𝑋2 + 𝜕2𝑉 𝜕𝑌2 ) (11) +𝑔[(1 − 𝜑)(𝜌𝛽)𝑏𝑓 + 𝜑(𝜌𝛽)𝑠](𝑇 − 𝑇𝑐 ) 𝑈 𝜕𝜃 𝜕𝑋 + 𝑉 𝜕𝜃 𝜕𝑌 = 𝛼𝑛𝑓 ( 𝜕2𝜃 𝜕𝑋2 + 𝜕2𝜃 𝜕𝑌2 ) (12) 9. conclusion this paper presents a comprehensive literature review of the most published papers in the field of natural convection between inner bodies located inside different complex enclosure shapes. the main conclusions are: abdulkadhim et. al /al-qadisiyah journal for engineering sciences 13 (2020) 080–090 89  the inner bodies inside trapezoidal, parallelogrammic enclosure are very limited, and more investigation should be done.  the studies regarding wavy enclosure are limited in a comparison with other simple shapes of enclosure despite its important applications is electronic equipment.  there are limitations in the studies of natural convection between the inner body located in a wavy enclosure.  multi-layers system inside a wavy enclosure is limited as most of the recent studies focus on nanofluid, porous media filled the enclosure but there are serious limitations when the nanofluid/porous media filled the space.  dufour and soret effect on natural flow for the multi-layer system are not investigated yet in full-details. acknowledgment we would like to thank our institutions (al-mustaqbal university college and al-qadisiyah university) for their supports and for giving us the time for writing and completing the present article review. references [1] r.s. kaluri, t. basak, analysis of distributed thermal management policy for energy-efficient processing of materials by natural convection, energy, 35(12) (2010) 5093-5107. 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[63] d. das, m. roy, t. basak, studies on natural convection within enclosures of various (non-square) shapes–a review, international journal of heat and mass transfer, 106 (2017) 356-406. al-qadisiyah journal for engineering sciences 14 (2021) 021–030 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mushtaq76h@gmail.com (mushtaq i. hasan ) https://doi.org/10.30772/qjes.v14i1.735 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. a review of earth to air heat exchanger as a passive cooling and heating technique and the affecting parameters mushtaq i. hasana* , dhay mohammed mutera adepartment of mechanical engineering, college of engineering, university of thi‐qar, nasiriyah 64001, iraq a r t i c l e i n f o article history: received 18 february 2021 received in revised form 31 march 2021 accepted 15 april 2021 keywords: computational fluid dynamics earth‐to‐air heat exchanger system geothermal energy heating, cooling affecting parameters thermal performance a b s t r a c t in the recent time the eahe is widely used as a passive cooling and heating technique due to the mounting thermal potential of earth as and as a result of energy crisis. in the past years many researches published including studying this type of heat exchanger and using it in many applications and many locations with different climate conditions. also, these researches investigated the most affecting parameters. in this paper a review is prepared to survey the published literature in this field to shed a light on the research. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction: the requirement to reduction a consumption in the energy for heating and cooling loads improved through past time. energy saving can be reached by depend on the renewable energies for example solar, wind and geothermal energy. for heating and cooling buildings it can be reliant on the ground for example warmth source in the winter and as heat sink in the summer. the utilities of the geothermal energy in heating and cooling spaces can be consummate by using (eahe) or moreover named earth heat exchanger singh et al. [1]. earth to air heat exchanger is a passive heating and cooling systems and it used in wide types of application for example heating and cooling greenhouse, industrial and inhabitation buildings. eahe is usually involves of pipe or more -pipes that inside the earth vertically or level. first the end of the tube is linked to the supply end of the fan and the other of side is open for air. while the air of flows during the inhumed of tubes, the heat is transmission from air to the contiguous soil through a summer period and the opposite in a winter. abbreviations de dry heat exchanger p.p pumping power cop coefficient of performance we wet heat exchanger eahe earth air heat exchanger http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 22 mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 2. applications: the earth to air heat exchanger used in many applications mainly in yusof et al. [2] 1) agricultural applications, 2) residential building equations 2.1. agricultural applications: okonkwo, w et al . [3] conducted an experimentally investigation the poultry house, with solar trombe wall which is equipped in order to the provide the ventilation, cooling and heating to a poultry house. they noted that the eahes maintained the temperature in the range from 28°c -35°c, 586 is grams the average body weight, the rate of mortality is around 3%and the feed conversion ratio is 1.87% . ahachad, m et al.[ 4] and fawaz, h et al. [ 6] performed experimentally the influence of the heat stress phenomenon are offered with simulating and modeling on the poultry house and it the effect of all parameter on the performance of the building (shape , ventilation, orientation etc) in north of morocco. from the results showed temperature will decrease per 2 air changes per hour by about 1.5°c, for 5 air changes per hour to 2.7 c° and for 10 air changes per hour 3.8 c°, the temperature of the inlet air reduction (up to 9 c°), and the production quality is enhancement. the ventilation lead to a full decrease of the cycle cooling capacity of 29.9 %. choi, salim et al. [5] studied the geothermal of heat pump for heating of poultry house, the geothermal of heat pump allows the lesser cost of heating, developed the production performance with decline amount of the gases discharges. kapica, j,et al. [7] estimated the decrease of co2 by using the solar-wind hybrid system for heating the house of poultry hey discovered that the larger system provides a greater co2 drop ,however the energy utilization ratio reductions . azzeddine l aknizi. [8 ]study plan and modeling of the earth to air he for the typical poultry house to estimate the potential of cooling and heating. they results found that the outlet temperature is 15°c for cooling mode of summer and heating mode in winter was 21.8°c.. azzeddine et al. [9] studied the thermal performance of the eahes through the parametrical to investigate the influences of the velocity of the air, the physical properties and the diameter of the pipe. the results displayed that a heat exchanger gives the coefficient of performance is higher with a upper efficiency and a system has the potential energy 146.38 m w h in heating and 104.3 m w h in cooling modes. wasseemet al. [10] studied experimentally the thermal performance of eahe in arid and humid soil in the basra in the semi desert region for a poultry shed. they found results advances the overall heat exchange efficiency. the (cop) of the wetted exchanger with an average cop of 6.41, while the dry exchanger ( de) obtained the value of 5. 07. on average, the exit temperature from the wet exchanger ( we )was 37.35°c ,however in the dry exchanger it was 38.91°c in the warmest hours of the day. also, the whe warmed the air over than the dry exchanger system, throughout the night time. 2.2. residential building: sodha et al. [11] investigated the eahes pipe length requisite in the cooling of the model with different earth surface dealings of delhi (india) for compound climate. observed from the result that for meeting the cooling load demand the dry sunny superficies requisite long tunnel, while, wet covered surface requisite the smallest length one. from the parametric of their research, saw that improvement for the temperature of the profiles in soil with great moisture of substances is faster than compared to the soil by little moisture substances. sharan and jadhav [12] used eahes to heating and cooling with modes was working in india ,ahmedabad, with yearly the middle temperature varieties between (23◦c and 43◦c). they found that a system was capable to rise the temperature with nearly 14◦c in january and reduce the temperature in may with a same value. the performance coefficient (cop) for heating and cooling was 3.8and 3.3, correspondingly. f. al-ajmi et al.[ 13] improved a theoretically model to calculate the earth to air heat exchanger temperature of air outlet and the potential of this cooling apparatus in a warm and dry weather. the model for the classic home of kuwait city. they found that the eahes had the ability to decrease home cooling energy request through the summer season by 30%. m.k. ghosal and g.n.tiwari .[14] in india, analytically model was advanced to study the efficiency of the earth thermal air heat exchanger combined greenhouse found in new delhi. their results presented that the thermal performance was suitable and advance by using of eahes . m.k.ghosal et al. [15] presented advanced numerical model of using the kept thermal energy of earth for space warming to investigate the potential with the advantage of (eahe) systems with the greenhouses situated in the delhi, india. experimental. they found that the air temperature were discovered to be on the average from( 7-8 c° ) greater than a same greenhouse when operational minus eahe. cheletal et al [16] executed experimentally during winter season thermal analysis with eahe systems for the building integrated. the dimensions of building air temperature showed that with using eahe system is an increase by 5 – 15.8 ˚c in the temperature of air of building compared by ambient air temperature, consequently the concluded that the eahe is appropriate to an axillary system for heating and cooling buildings . transient systems simulation software (trnsys) by abdullahi ahmed. et al. [ 17] estimated a thermal performance of the eahes for unlike shapes and work conditions in the uk. their result showed major enhancement in potential and internal thermal conditions to decrease use of the energy concentrated conservative cooling system . bansal et al. [18] and vaz et al. [20] showed out a numerical studies by the help of fluent based on the computational fluid dynamics(cfd) surroundings for calculating the heating and cooling capability of earth to air-pipe heat exchanger (eaphe ) system . mohammad jia et al. [19] investigated experimentally the measurement the capacity of cooling the etahes in bangladesh.. they found that the cop and the capacity of cooling increased with the increase of mass rate of flow ,the outlet temperature declined below ambient temperature as the inlet air. khalajzadeh et al. [21] estimated the performance thermal of earth heat exchanger (ghe) and evaporative cooler hybrid systems of tehran, iran in summer climate. they [60] saw that the hybrid systems are able to change the conventional air conditioner efficiently and its cooling efficacy is higher than unity. tudor et al. [22] analyzed and advanced the suitability of using the eahes as the passive method for heating and cooling of houses under the climate for five cities of south – eastern europe. they obtained that the exit air temperature from eahes noted during july and august month was the maximum monthly average, while in january month was the minimum. moreover, they discussed, best the thermal performance and the high heat gain record with using pipe diameter of 100 mm instead of 200 and 300 mm &17 m pipe length instead of 10 and 5 m, 2.5 & 3.5 m burial depth in its place of 1 m .ramirez-davila et al [23] executed numerically study on the performance thermal of the (eathe) system by changing climatic conditions for three cities in mexico. their results presented that use of eahes was suitable for extreme and enough temperature areas wherever the thermal inertia mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 23 influence is greater in soil. earth to air heat exchangers (eahe) s with solar chimneys haorong li. et al. [24]. experiments studied to estimate the performance the system in summer to investigates an innovative passive air conditioning system. they noted that eahe full cooling aptitude in that experimental was 3308 w, while the maximum cooling ability of coupled system eahes and solar chimneys was 2582 w, and they concluded that the increase in the exit air temperature . trilok singh bisoniya et al.[25] discussed the decrease a cooling of energy demand of buildings experimentally in dry and hot climate bhopal (central india) .observations of ; temperature was drop from 12.90 °c to11.30 °c and the gain energy of cooling of eahes improve 0.85 to 1.87 mj h for the air flow of speeds of 2m/s to 5m/s . trilok singh bisoniya et al. [26]discussed the efficiency of decreasing the heat of energy request of buildings in dry and cold winter climate conditions by using eahe. experimental results showed that heating potential various from 0.59 to 1.22mj h for air of flow speeds of 2 to 5 m/s ,also correlation coefficient and root mean square of percentages deviance of 2.1% and 0.999. nitish shrestha et al. [27] performance analysis of eahe at different atmospheric conditions, experimental that system consist of finned tube. observed that in cooling mode the inlet temperature of the air drops with rise in the pipe length. the temperature reduction for a length of 1.2m differs from 1-3 c° at velocity 6.5m/sec. g.n. tiwari et al. [28] experimentally estimate thermal conductivity of a soil, the eahe system has been planned ,measurement of room with improved values of radius of pipe, length of pipe, number of air variations, and depth at which( he) be fixed under the superficies of the ground. they observed that the outlet air temperature a reduction of( 5 – 6 °c ) in summer for a number of 5 air variations with 0.10 m and 21 m enhanced diameter and pipe length respectively. sanjeev jakhar. et al. [29] expected experimentally the thermal of performance of earth to air tunnel heat exchanger (eathe ) system linked by the solar air heating duct to develop the capacity of heating eathe system. they noted that the capability of heating of eathe system improved from 1217.625 to 1280.753 kwh after it was linked with the solar air heating duct with a significant rise of temperature of room by 1.1– 3.5 ◦c . the effect of a thermal performance of eahe by its design parameters are planned numerically by thakur et al.[ 30]. from result their displayed that the thermal performance improved with using finned pipe wherever the air temperature was recorded drop about 20.5 ˚c compared with 17.7 ˚c when the pipe is finless. numerical study by benhammou et al. [ 31] to estimate the thermal of performance of the (eahe)system a passing one dimensional season below the climate conditions of algerian sahara. through summer . they found that the decline in the air temperature between inside and exit of the system is greater with high the inlet air temperature consequently by the tube length of 50 m, the drop in the air of temperature is 11 ˚c for the air inside temperature of 44 ˚c and is 5 c° for the air inside temperature of 29 ˚c. after observing their results they reached to that the thermal of performance of eahes developed at great air temperature through the summer season. hiresh .et al. [32] performed an experimental operate to study the earth to air heat exchanger performance. they found that about 261.5 w was the maximum quantity of heat transfer from air to surrounding soil at 5 m/s the velocity of air. also, they explained from the results that with temperature of inlet air changing from 32 ˚c to 40.3 ˚c the exit air temperature increased with 4.5 ˚c at 5 m/s. anuj mathur et al [33] showed an numerical the problematic of increase of heat nearby the tube during the summer period by soil having low moisture content and great specific heat. they obtained that the saturation of soil with heat hampers the performance of eahes and the heat can be enhanced in winter days with running the system. sanjeev et al. [34] discuss experimentally and simulation typical with using trnsys 17 to evaluation the heating of potential of earth air heat exchanger with and without solar heat pipe (shd). they establish through the simulation results and experimental results that the heating capacity and exit air of temperature of eahes enhanced by using solar heat duct. figure 1: experimental set-up of eathe coupled with solar air heating duct. moreover, in the winter season they found that the exit air of temperature improved by reduced air velocity. badgaiyan p et al. [35]. evaluated the performance of eahe with several operating parameters was studied experimentally and numerically. they proved that thermal performance enhanced with increasing the length of pipe, wherever the outlet temperature reduced. additionally, they concluded that for three velocity of air flow (4, 5, and 6 m/s). the less outside temperature found with 4 m/s air velocity .omar hamdi et al. [36] study the performance of the earth -to-air heat exchanger (eahes) and discovery out the usefulness of the cooling of buildings in the hot region in the south east of the algeria at biskra university. from result observed the air temperature at the outside of the exchanger is about 24 °c at the starting of may to reach nearly 32 c° in early september. nasreddine sakhri1 et al. [ 37] experimentally study is showed on the performance of a combined system :eahes and the solar chimney. as an arid region in the north-west of the city of bechar, algeria. they showed results of the capacity of the system to rise the outlet air temperature exit the system by 14 °c and produce the heating mode. the inside temperature increased ,then, the system travelled to a cooling mode by decreasing this temperature of air by 11.6 °c (from 36.2 °c at the inside to 24.6 °c at the outside ). three dimensional eahes combined with a house building by mushtaq i. hasan and sajad w. noori [ 38] discussed a numerical the potential for drop in energy consumption for heating and cooling loads by using the eahe system in southern iraq in the weather of nasiriya city .they results showed that thermal performance and the outlet air temperature improved with length and the pipe of number of the eahe system. so, the eahes is higher appropriate for work through winter month , wherever , the drop in energy saving and heating capacity are great compared with the decrease in energy saving and cooling capacity in summer months. 24 mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 2.3.study the earth to air heat exchanger performance with solar chimney: also, they used matlab software with cfd modeling by. salman h et al. [ 39] studied to the investigating the influence of tube length , the air of speed , and tube diameter on a performance of the air thermal he system in basrah, used (eahe) collected with solar chimney (sc) .the results have shown that the temperature at outlet from the buried pipe declines with rising the pipe length , declining pipe diameter, declining mass flow rates of flowing air in the tube and rising depths up to 4m. figure 2: the earth–tube–air heat exchanger system. earth to -air heat exchangers (eahes) with solar chimneys by haorong li. et al. [ 24]. experiments studied to evaluate the performance the system in summer to investigates an innovative passive air conditioning system. they noted that eahe maximum cooling capacity during that experimental was 3308 w, while the full cooling capability of coupled system eahes and solar chimneys was 2582 w, and they saw that the rise in the outside air temperature . nasreddine sakhri1. et al. [ 40] an experimental investigation is showed on the performance of a combined system: earth-to-air heat exchanger and a solar chimney, as an arid region in the north-west of the city of bechar, algeria. they showed results the capacity of the system to rise the outlet air temperature exit the system with 14 °c and produce a heating mode. the inside temperature increased ,then, a system travelled to the cooling mode by decreasing this temperature of air with 11.6 °c ( from 36.2 °c at the inside to 24.6 °c at the exit ). 2.4.e ffect of soil type and moisture content on eahes: after the parametric study by puri. [40] saw that advance of temperature profiles is quicker in soil by great humidity substances than to soil by little humidity contents. their result improvement of the temperature with soil moisture contents.. sodha et al. [11] studied the earth air he pipe length requisite in the cooling of the model with different earth surface dealings of delhi (india) for compound climate. observed from the result that for meeting the cooling load demand the dry sunny surface requisite long tunnel, while, wet shaded superficies requisite the smallest length one. and , improvement of the temperature of the profiles in soil by great moisture of contents is faster than compared to the soil with little moisture substances. santamouris et al. [41] studied the effect of different earth superficies the boundary of conditions on the of a multiple and a single parallel eahes they provide efficiency is high by using eahe.. clara et al. [42] presented the influence of soil shield, soil composition and climate, on the performance of the eahe systems. they reached that the bare surface for heating develops the performance of the eahe, while the surface humid for the cooling object is better. they additionally ,showed that the higher water contented and a carefully packed soil nearby the tubes of eahes develop eahe system performance. mathur et al. [43-44-45] evaluated that the soil temperature about of the tube depends on the thermal conductivity of soil wherever the soil by a lesser thermal conductivity will saturate at the quicker than to the soil with the greater thermal conductivity. mushtaq i. hasan and sajad w. noori .[46] explained an numerical the influence of some plan and environmental factors ( the material of pipe and the thickness of pipe wall, moist content of soil,) on the overall performance of an eahe systems. they showed that the saturated soil shows the greatest general performance of eahes compared with further soils, also the wall thickness and tube material no significant influence on the overall performance. agrawal. et al. [47] discuss experimentally the influence sub-soil moisture content in hot and arid climate to enhance soil thermal properties and its influence on eathe the pipe of length and thermal performance requisite for selected temperature declined for the summer cooling. they noted that cop and the average heat transfer rate improved by 24.0% and 24.1% correspondingly for 20% moisture contented at 30 m eathes the pipe of length than to the dry system. kamal kumar a et al. [48] studied the moisture contented and its effect on the pipe of length and the performance of thermal necessary for selected temperature increase in the winter season. they saw that the coefficient of performance and the average heat transfer rise up to 26.1% and 26.0% correspondingly, for 15% the moisture contented at 30 m length pipe of eaphe system as than to the arid climate. 3. affecting parameters: 3.1. the effect of flow velocity: bansal et al. [50] numerical study carried out on the ethe systems through the winter period .from their results they proved that 23.4 m of long the earth air thermal heat exchanger system can increase air of temperature for the flow of speeds of 2–5 m/s in the range from 4.1–4.8 c°. vikas et al [51, 54] ,sanjeev et al. [34] showed experimentally and numerically the influence of the air speed on the performance of earth to air heat exchanger system . their result found experimentally and numerically during summer and winter seasons that the exit air temperature improved with rising the air of speed. vikas bansal. et al. [53] presented experimentally the effect of the operative parameters ( air of velocity, the pipe materials ) on a performance of thermal of epahe systems to reduction the cooling capacity of the buildings in summer period. they found the air temperature reduce with rise the velocity, and the performance of coefficient of the system differs from 1.9 to 2.9 for rise in speed from 2.0 to 5.0 m/s. v. bansal et al.[ 52-56] performed the numerical simulation of cooling capacity and thermal performance of an eahes in the hot and dry conditions. they have saw that the velocity of air during a pipe buried has been noted significantly influenced the performance of the earth to air heat exchanger . mohammad hossein et al. [ 55] carried out experimentally treatments on the influence of important parameters, counting pipe material and burial pipe (pipe of length, depth, air velocity)and on the performance of eahe systems .they obtained that 5.5 of cop of the system for cooling type was greater than 3.5 for heating cop of material which is higher for steel than pvc. also, the differential temperatures were 14.4 c° and 9.4 c° for cooling and heating modes . mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 25 figure 3: schematic of the eahe piping design. misra et al. [57] estimate the variant of derating element of the eahes because of the influence of the parameters. they results displayed that the rise in the flow of velocity it causes decline in thermal performance of eahes. nitish shrestha1. et al. [28] performance analysis of eahe at different atmospheric conditions observed that in cooling type the inlet temperature of the air drops with rise in the pipe length. the temperature reduction for a length of 1.2m differs from 1-3 c° at velocity 6.5m/sec. salman h et al. [ 39]. studied to show the effect of the tube of length, air speed , and pipe diameter on the performance of the air thermal he system in basrah . the result have presented that the potential of earth tube is providing lesser exit temperature of air inside to the area. they discover that the temperature at outlet from the buried pipe declines with rising the length of pipe, declining pipe diameter, declining mass flow rates of flowing air in the tube and rising depths above to 4.m .experimental and theoretical study have been by mohammed benhammou and belkacem draoui [ 58] to show the impact of dynamical and geometrical parameters on the thermal performance of eahes the thermal performance of (eahes) to the summer cooling in the algerian sahara. their result obtained that the air exit temperature declines with rising the length of pipe but it rises with rising the velocity of air and pipe cross section , also experimental that cop declined quickly with increasing the velocity of air. numerical study by benhammou et al. [ 31] to estimate the thermal of performance of earth to air heat exchanger system a passing one dimensional season below the climate conditions of algerian sahara. through summer . they noted from the results that the air temperature in outlet from the system with pipe length of 30 m is less by 2 ˚c compared with 10 m pipe length. also, they observed that the air temperature in outlet decrease by 1.8 and 1.2 with using 10 cm pipe diameter 30 cm and 1 m/s the air of velocity in place of 3 m/s. similarly with the found of krarti et al. [49]. ahmed et al [59].discussed numerical and an experimental investigation about the thermal performance eahe systems with diverse parameters (pipe of length, pipe space ,pipe diameter and pipe material) in egyptian weather conditions. the results showed by using computational fluid dynamic saw that the air temperature at exit increases with reduced diameter, increasing pipe length and decreasing the flow rate. sanjeev j et al. [34] showed experiment was through winter season for the influence of diverse inside flow velocities, concluded that the best rise in eahe exit temperature at the speed 5m/s compared with velocity at 2.5m/s and 3.5m/s. while, jahkar et al [60] studied the parametric were done to analyses the influence of mass flow rate, radius of buried pipe , length of tube and the material of pipe on the performance study of a ewhe system. they obtained that by an rise in mass flow rate, the temperature in the outlet of ehwe rise . figure 4: schematic diagram of the experimental setup. badgaiyan p et al. [35] estimated the performance of eahes with several operating parameters was studied. . they proved that thermal performance enhanced with increasing the length of pipe, wherever the outlet temperature reduced. additionally, they concluded that for three velocity of air flow (4, 5, and 6 m/s). the less outlet temperature found with 4 m/s air velocity. mushtaq i. hasan and sajad w. noori [61] study a numerically the overall performance of the eahe by five forms of the eahes channel. they discover that the outlet air temperature reduced through the summer and increased through the winter season period, with increasing pipe of length or declining the air of speed, so, they showed that there is the circular form gives the greatest general performance since it has the smallest pressure drop than by further figures. 3.2. effect of length of pipe: mihalakakou et al. (1995) [62] discuss the parametrical model in which changing parameters were tube radius ,pipe length, speed of the air inlet the pipe and the buried of depth pipe under the earth superficies. conclude with increase the velocity the temperature is enhance. bansal et al. [50] numerical study carried out on the earth air he systems through the winter periods .from their results they proved that 23.4 m of long the earth air thermal he systems can increase the air of temperature for a flow of velocities of 2–5 m/s in the range from 4.1–4.8 °c,. maerefat and haghighi [63] ,pohstiri et al., [65] have advanced a mathematically typical based on energy conservation equations and resolved by iterative way to find out the ability of the solar chimney and eahe system. pipe lengths of eahe must be used to afford a best thermal security condition less than 35m .they results showed of the influence of eahes tube radius on the system performance exposes that the rise of the eahes diameter up to 0.5m does not rise the room air temperature. ascione et al.[64].evaluated the energy of performance of the air to conditioned building joined by ground heat exchanger (ghe) in the italian weather. from their result obtained for a 50 m length of ground heat exchanger pipe was about 14.2 kwh/m2 is the maximum major energy that saving . mohammad hossein et al. [ 55] carried out experimentally treatments on the influence of important parameters, counting pipe material and burial pipe (pipe of length, depth, air velocities )and on the performance of an eahe systems .they obtained that 5.5 of cop of the system for cooling style was greater than 3.5 for heating cop of material which is higher for steel than pvc. also, the differential temperatures were 14.4◦c and 9.4◦c for cooling and heating modes . academics[66-67] have discovered that the system provide best the thermal of performance with rising the tube length burying, the pipe at a depth above to 3 m, expanding the superficies of a pipe, decreasing the tube radius and the air flow rate inlet the tube. nitish shrestha1. et al. [28] performance analysis of eahes at different atmospheric conditions 26 mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 observed that in cooling style the inlet temperature of the air drops with rise in the tube length. the temperature reduction for the length of 1.2m differs from 1-3 c° at velocity 6.5m/sec. experimental and theoretical study have been by mohammed benhammou and belkacem draoui [ 58] to show the influence of dynamical and geometrical parameters on the thermal performance of eahes the thermal performance of (eahes) for summer cooling during the algerian sahara region. their result concluded that the air exit temperature declines with rising the length of pipe, then it increased with increasing the velocity of air and pipe cross section , also experimental that the coefficient of performance declined fast with rises the velocity of air. numerical study by benhammou et al. [ 31] to estimate the thermal of performance of earth to air heat exchanger system a passing one dimensional season below the climate conditions of algerian sahara. through summer . they noted that the air temperature in outlet from the system with pipe length of 30 m is less by 2 ˚c compared with 10 m pipe length. also, they observed that the air temperature in outlet decrease by 1.8 and 1.2 with using 10 cm pipe diameter 30 cm and 1 m/s the air of velocity in place of 3 m/s. similarly with the found of[49] . ahmed et al [59] discussed numerical and experimentally investigation about the thermal performance of eahes with parameters (pipe of length , pipe space ,pipe diameter and pipe material) in egyptian weather conditions. the results showed by using computational fluid dynamic observed that the air temperature at exit increases with reduced diameter, increasing tube length and decreasing the flow rate. jahkar et al [67] studied the parametric were done to analyses the influence of mass flow rates, radius of buried tube , pipe length and pipe substance on the performance analysis of the ewhes. they obtained that with the rise in mass flow rate, the temperature in the outlet of ehwes rises. while [76] showed experiment was through winter season for the influence of diverse inside flow velocities, concluded that the best growth in eahe exit temperature at the velocity 5m/s than to velocity at 2.5m/s and 3.5m/s. badgaiyan p et al. [35] estimated the performance of eahe with several working parameters was studied. they proved that thermal performance enhanced with increasing the length of pipe, wherever the outlet temperature reduced. additionally, they concluded that for three velocity of air flow (4, 5, and 6 m/s). the less outlet temperature found with 4 m/s air velocity.. mushtaq i. hasan and sajajd w. noori .[61] study a numerically the general performance of the eahe by five forms of the earth air heat exchanger channel. they discovered that the exit air temperature reduced through the summer and increased through the winter period, with rising the pipe of length or declining the air of velocity, so, they established that there is the circular form gives the greatest general performance since it has the smallest pressure of drop compared by further figures.. agrawal. et al. [48]studied experimentally the influence sub-soil humidity content in hot and arid climate to improve soil thermal properties and its influence on eathe the tube of length and thermal performance requisite for selected temperature declined for the summer cooling. , cop and the average heat transfer rate improved by 24.0% and 24.1% correspondingly for 20% moisture contented at 30 m eathe the pipe of length as compared to the arid system. mushtaq i. hasan and sajad w. noori [46] studied numerically the effect of the parameters (inside condition, pipe diameter, pipe length, and exit condition) on the general performance of the eahes .they pretend results presented that the eahe systems with pipe radius ( 6 in) has the best values of general performance. then, the diameter of pipe more suitable is 2 in from the thermal of performance point of overview. 3.3. effect of diameter of pipe: mihalakakou et al. (1995) [62] discuss the parametrical typical in which changing parameters were pipe radius ,pipe length, speed of the air inlet the cylinder and the buried of depth pipe under the ground superficies. conclude with increase the velocity the temperature is enhance.. maerefat and haghighi [63], pohstiri et al. [65] have advanced the mathematical typical based on energy conservation equations and resolved by iterative way to find out the ability of the solar chimney and eahe system. pipe lengths of eahe must be used to afford a best thermal security condition less than 35m .they results showed of the influence of eahe system tube radius on the system of performance exposes that the rise of the eahes diameter above to 0.5m does not rise the area air temperature .academics [66,67] have discovered that the system provide best the thermal of performance by rising the tube length burying, the tube at the depth up to 3 m, expanding the superficies of the pipe, decreasing the tube diameter and the air flow rates inlet the pipe. g.n. tiwari et al. [69] experimentally estimate thermal conductivity of the soil, earth to air heat exchanger system has been planned ,measurement of room with improved values of radius of pipe, length of pipe, number of air variations, and depth at which( he). they observed that the exit air temperature a reduction of 5 – 6 c° in summer for the number of 5 air variants with 0.10 m and 21 m enhanced diameter and length of pipe correspondingly. salman h et al. [ 39] studied to investigate the impact of the pipe of length, air velocity , and pipe diameter on performance of the air thermal he system in basrah . the result have presented that the potential of earth tube is providing lesser outside temperature of air inside to the area. they discover that the temperature at outlet from the buried pipe declines with rising the length of pipe , declining pipe radius, declining mass flow rates of the flowing air in the tube and rising depths above to 4m. numerical study by benhammou et al. [ 31] to estimate the thermal of performance of earth air he system a passing one dimensional season below the climate conditions of algerian sahara. through summer . they noted from the results that the air temperature in outlet from the system with pipe length of 30 m is less by 2 ˚c compared with 10 m pipe length. also, they observed that the air temperature in outlet decrease by 1.8 and 1.2 with using 10 cm pipe diameter 30 cm and 1 m/s the air of velocity in place of 3 m/s. similarly with the found of [49]. ahmed et al . [59] discussed numerical and experimentally investigation about the thermal performance of the eahe system with diverse parameters ( pipe length , pipe space ,pipe diameter and pipe material) in egyptian weather conditions. the results showed by using computational fluid dynamic saw that the air temperature at outlet increases with reduced radius, increasing tube length and decreasing the flow rate. jahkar et al. [68] studied the parametric were done to analyses the influence of mass flow rate, diameter of buried tube , pipe length and tube of material on the performance enquiry of the ewhe system . they obtained that with an rise in mass flow rates, the temperature in the outlet of ehwe rises . while [76] showed experiment was through winter season for the influence of diverse inlet flow velocity, concluded that the batter growth in eahe exit temperature at the velocity 5m/s than to the speed at 2.5m/s and 3.5m/s. mushtaq i. hasan and sajad w. noori [48] studied numerically the influence of the parameters (inside condition, pipe diameter, pipe length, and exit condition) on the general performance of the earth air heat exchanger( eahe) system .they simulated result presented that the eahe systems by pipe diameter ( 6 in) has the better values of general performance. then, the diameter of tube more suitable is 2 in from the thermal performance point of overview. mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 27 3.4. effect of pipe of thickness: mushtaq i. hasan and sajad w. noori (2018)[70] explained an numerical the influence of specific design and environmental factors (pipe material and thickness of tube wall, moist content of soil,) on the overall performance of the earth to air heat exchangers. they showed that the saturated soil displays the greatest general performance of eahes than by other soils, also the wall thickness and pipe material no significant influence on the overall performance. figure 5: schematic of eahe system mushtaq i. hasan and sajad w. noori..[71] studied numerically the effect of wall thickness and tube material on the overall performance of eahes . their results noted the more suitable to use is pvc pipe because it is non-corrosive and less cost compared with steel pipe. the influence of wall thickness on the overall performance is less and can be neglected. 3.5. effect of pipe material: vikas bansal. et al. [72] discuss experimentally the influence of the operative parameters ( the air velocity, the tube material) on the thermal performance of epahe systems to decrease the cooling capacity of the buildings in summer. they found the air temperature reduce with rise the speed, and the cop of the system differs from 1.9 to 2.9 for rise in the velocity of 2.0 to 5.0 m/s. in addition the maximum rises in temperature for steel and pvc pipes are 10.3 and 12.7 8c correspondingly. v. bansal et al. [52-56] performed the numerical simulation of cooling capacity and thermal performance of eahes in the warm and dry conditions. they have observed that the performance of the eahes is not significantly influenced by the material of a pipe buried, while the velocity of air during a pipe buried has been noted significantly influenced the performance of the eahes . mohammad hossein et al. [ 55] carried experimentally treatments the influence of important parameters, counting pipe material and burial pipe (pipe length, depth, air velocity ) and on the performance of the eahe system. they discovered that 5.5 of cop of the system to cooling mode was greater than 3.5 for heating cop of material which is higher for steel than pvc. also, the differential temperatures were 14.4◦c and 9.4◦c for cooling and heating types . hatraf et al. [73] have studied the parameters effectiveness the performance of eahe during experimentation and modeling. they have done design using the simple typical varied some and the supply of the air temperature. they found was that the pipe of material has no influence on a performance of the he, which is arrangement by the found of bansal et. al [52]. serageldin et al., [75] calculated the thermal of performance of the eahes used to cooling and heating in the egyptian climate conditions. they have advanced the mathematical typical founded on unsteady, one dimensional, quasi to state for energy conservation equation three diverse kinds of pipe material were used , specifically steel , pvc and the copper. the exit air of temperature was 19.7 °c in pvc tube, and 19.8 °c for together copper and steel correspondingly. so, it is established that the difference in the exit air temperature for many pipe material is also lesser and later it is negligible. mushtaq i. hasan and sajad w. noori [ 70] , mohd, noor a et al. [74] explained a numerical the influence of certain design and environmental factors (tube material and thickness of pipe wall, moist content of soil,) on the overall performance of the earth to air heat exchangers systems in nasiriyah town in southern of iraq. they showed that the saturated soil displays the greatest general performance of eahes than with further soils , also the wall thickness and pipe material no significant influence on the overall performance. mushtaq i. hasan and sajad w. noori.[71] studied numerically the influence of wall thickness and tube material on the general performance of eahe. the results showed the more suitable to use is pvc pipe because it is non-corrosive and less cost compared with steel pipe. the influence of wall thickness on the overall performance is less and can be neglected, the pressure drop and the exit air temperature for the two materials improved with rising the velocity of air. 3.6. effect of pipe depth buried underground: pfafferot.[75] and pfafferot et al. [76] studied the average of yearly temperature profile at depths of 1 m, 2 m, 4 m and 8 m. they results presented that the temperature at depths of 4 and 8 m was stable during the time in the range of 9 to 13°c. cucumo et al. [77] explained the effect of the burial pipe depth on the performance of earth to air heat exchanger systems. the model allowable also to calculate the temperature of air inlet the tube and of soil nearby the buried pipe, taking into description the thermal perturbation of greater free superficies and the possible phase change (concentration) in the buried pipes. a like model was advanced by su et al. [78] for discuss the thermal performance of eahes used for the building energy saving. mohammad hossein et al. [55] carried experimentally treatments the influence of important parameters, counting pipe material and burial pipe (pipe length, depth, air speed) and on the performance of an eahe. they discovered that 5.5 of cop of the system for the cooling style was greater than 3.5 for heating cop of material which is higher for steel than pvc. also, the differential temperatures were 14.4◦c and 9.4◦c for cooling and heating modes. academics [66,67] have discovered that a system provides best the thermal of performance by rising the pipe length burying, the pipe at a depth up to 3 m, expanding the superficies of the pipe, decreasing the pipe diameter and the air flow rates inlet the pipe. mushtaq i. hasan and sajad w. noori.[79] thesis discussed a numerical study about the potential decrease in the request of energy and the overall performance of (eahe) systems for heating and cooling of the house buildings by eahe system of southern of iraq in nasiriyah city. they showed that more appropriate to use is the eahe system of case 2 compared with case 1 and case 3 ii (consist of one layer buried with 3 m depth of eahe system and the ehae of this case3 ii buried with depth of 4 m ) with saving in energy 17.84% of winter at january months and 9.33 % of summer months at august month. 28 mushtaq i. hasan , dhay mohammed muter /al-qadisiyah journal for engineering sciences 14 (2021) 021–030 4.the disadvantages. of this application: 1. possibility of depletion of geothermal sources. 2. high investment costs for geothermal system. 3. land requirements for geothermal system to be installed. 4. environmental concerns about greenhouse emissions. 5. conclusions: the eahe is one of the systems that can be used for decreasing energy consumed in buildings ,thermal performance of the eahe depends on several chief influences such as under earth temperature difference, plan and specification of the eahe pipe, the following conclusions can be decided: 1.thermal performance improved with using finned pipe wherever the air temperature was recorded drop about 20.5 ˚c compared with 17.7 c° when the pipe is finless 2. the wall thickness and pipe material no significant influence on the overall performance 3. the effect of eahe system tube diameter on the system of performance exposes that the rise of the eahes diameter lead to increase in area of pipe that it cause increase in temperature outside of pipe and it cause decrease in pressure drop. 4. the eahes had the ability to decrease home cooling energy request through the summer season by 30%. 5. the increase in length of pipe of eahe lead to decline in the temperature interning to the poultry houses, then it increased with increasing the velocity of air and pipe cross section. references: [1] b-m d, b.d, and r .singh, study of a balastic clay. geofrontiers ,( 42)(2011) 480-487. 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[79] m. i. hasan and s w. noori. study the potential of using earth to air heat exchanger for cooling and heating of the residual building in iraq. a thesis submitted to the department of mechanical engineering, college of engineering, thi-qar university, 2018. article al-qadisiyah journal for engineering sciences 12 (2019) 118–126 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. . e-mail address: sheamaaj@gmail.com (kadhim n. abid) https://doi.org/10.30772/qjes.v12i2.604 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. use of bypass cement dust from al-kufa cement factory for production of glass ceramic material kadhim n. abid*a, rabiha s. yasseb, and shaymaa j. salihb a general directorate vocational education/ ministry of education. b dept. production eng. & metallurgy, university of technology. ____________________________________________________________________________________________________________________________ a r t i c l e i n f o article history: received 15 july 2019 received in revised form 4 august 2019 accepted 8 august 2019 keywords: bypass glass ceramic main material reinforcing materials sintering process a b s t r a c t bypass cement dust was supplied from the alkufa cement factory, which has been used in preparing glass ceramic material. the percentage of bypass cement dust, which is included in the overall batch, is about 30 wt %. the bypass cement dust composition has been modified by adding other materials like marble, granite, and silica, to prepare glass ceramic material by powder technology. the prepared samples with different ratios ingredients were pressed under a load of 15 tons/cm2 for 90 sec, in a steel mold of 30 mm in diameter, liquid phase sintering is carried out by using high-temperature furnace at 100 – 1250 º c and 208/240 vac. techniques including sem (scanning electron microscopy) and xrd (x-ray diffraction) tests were then used to evaluate the produced material. the obtained glass ceramic material has high bulk and apparent density, low apparent porosity, high compression strength and hardness , low electrical and thermal conductivity. the xrd and sem results showed that glass ceramic materials are formed. the phase transformation has happened and the titanite, wollastonite, diopside, periclase, and silica condense clusters phase are formed, which are the important phases of glass ceramic. tests show that the sample a5 contains 38% bypass cement dust, 30%granite, and 32% silica; and the sample c5 contains 28% bypass, granite 30%, marble 10%, and silica 32%; and the sample b4 contains 59% bypass, 25% marble, and 16% silica. showing properties a5 and c5 which conform to that of glass ceramic properties better than b4. the research is considered a pioneer work in the field of investment of dust of bypass cement for producing glass ceramic materials. it represents an important step and could be the basis for future researches leading to the achievement of glass ceramic production in iraq. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction glass ceramic is considered to be one of the most versatile and precise materials which are used in different fields of industry. glass ceramic has a wide range of considerable properties such as heat insulation, high strength, thermal shock resistance, hightemperature stability, toughness, and capabilities of isolation [1]. glass ceramic materials, which have been prepared via controlling glass crystallization can be used for different purposes depending on their uniform, reproducible fine grained microstructure, the absence of porosity and many other different characteristics that may be regulated by changes in composition and the process of heat treatment. in fact, glass ceramics that are based on the structures of chain silicate were established [2]. a number of works were performed on the diopsideanorthitecelsian (mgcasi2o6caal2si2o8 baal2si2o8) system [3]. the nature and characteristics of crystalline phases and the material microstructure were reported as the most significant parameters that affect technical characteristics of glass ceramic [4]. controlled bulk crystallization has been produced by the http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i1. kadhim n. abid et. al /al-qadisiyah journal for engineering sciences 12 (2019) 118–126 119 devitrification technique which has been most utilized used to produce glass ceramics. researchers have been mostly focused on glass in systems like sio2-al2o3 , mgo-al2o3sio2, and cao-al2o3-sio2 [5]. in order to avoid uncontrolled crystallizing, controlled surface crystallizing has been performed on glasses in systems mgo-al2o3-sio2 and cao-al2o3-sio2 [6]. the basic phases of crystalline have been found to be anorthite (caal2si2o8), titanite (catisio5), wollastonite (casio3), spinel (mgal2o4) forsterite (mg2sio4), and cordierite ((mg, fe)2al4si5o18), [6]. research on cao-mgo-al2o3-sio2 system is significant as well in order to understand the reaction that occurs in the rocks, mgo refractories, and blast furnace slag [7]. the glass ceramic material does not have a fixed chemical composition or a specific crystal structure, which is an oxide. it is composed of the matrix component material and the added material for reinforcement and the auxiliary in the sintering, and there are other materials that can be added for installation to improve the mechanical properties and to control on the color of the product [7]. glass ceramics are composite materials that generally consist of combining two or more materials to obtain a material with geometric and physical properties that differ from the properties of the composition and the resulting material is better than its components. composite materials consist of two phases matrix phase and reinforcing phase[8]. in the scientific literature, ceramic materials are compounds between mineral and non-metallic elements, most of which are oxides, nitrides, and carbides. it has a complex crystalline structure with ionic, covalent, or common bonds [9]. cement kiln dust is produced in cement kilns and related devices. dust from raw mixture and plant surroundings are typically contained by water sprays and closed systems. throughout burning, gas flows entrain a considerable amount of dust which makes up a portion of the exit gas from the kiln. the dust of the cement kiln which has been generated is strongly dependent on the chemistry of the raw materials, velocities of the gas in the kiln, and type of the process. other elements like the efficiency of the kiln and dust collection system design are vitally important. a variety of approaches have been utilized for capturing dust, which includes bag filtration and electrostatic precipitation. in the case where the dust of the cement kiln includes low amounts of chemicals (less than or equal to 75wt%) like the chlorides and alkalis, then there is a possibility of returning dust in the kiln as a part of raw mixture [10]. dust of cement kiln which has not been reused this way may be utilized in many other different industrial applications, for instance, is a form of subbase in the construction of road giving its hydrating features, in a form of a cement additive in the process of grinding, as a backfill material in mining, and as an alkali source in chemical processing (such as potassium sulfate for extracting potassium oxide) [11]. cement dust is an undesirable cement industry by-product, instead of being discharged in the atmosphere, which is why, it is typically kept behind filters, as a sufficient, active particulate residue. the concentration of cement dust in the chimneys does not exceed 150 g /cm3 at the outer boundary of the al-kufa cement factory in the direction of the wind [10]. efforts to recycle the dust result in a maximal utilization of only around 10% to 20%, the rest amount which is quite large is, in general, landfilled or loaded on trucks and thrown in near open surface impoundments, the dust of disposal permits massive amounts of light-weight, erosive, fine powder to be released to the environment with the wind blowing, and that poses severe health and environmental risks. the chemical composition of bypass cement dust indicates the potential of using it in glass ceramic and glass industries [11]. due to the fact both those industries are known for having numerous applications in commerce, for instance, in the microelectronics industry and constructions, utilizing bypass dust of cement for the production of glass ceramic materials is greatly significant in technological scientific, and economic aspects [11]. in this research, bypass cement dust from al-kufa cement factory is used to produce glass ceramic materials. 2. materials and methods 2.1. materials used the matrix material powder (bypass cement dust) was supplied from the al-kufa cement factory. the reinforcing materials (granite, marble, and silica) were obtained from the iraqi market. 2.2. experimental procedures the first stage did the chemical composition of matrix material (bypass cement dust) and reinforcing materials (granite and marble) is presented in table 1. xrf was used to analysis the reinforcement material of silica, showing the purity of 62.4% .in the second stage, the reinforcement materials were broken by jaw crusher (42781 haan-2013) . the material size was reduced by a ball mill (retsch, model pm 100) at speed 300 rpm for 25 min. then the materials were sieved by sieve shaker (ad60-01) according to astm at vibration 60 hz for 15 min to obtain particle size ≤ 0.25 mm. the third stage mixing of the powders by a ceramic container perform by different ratios of matrix material (bypass cement dust) and reinforcing materials for 50 min, as shown in table 2. the fourth stage did the pressing process of the specimens were compression by using load 15 ton for 90 sec and using a cold pressing technique in one direction (uniaxial pressing) in a steel mold with diameter 30mm. the last stage did the sintering process by using an electric furnace ( german nabertherm). the samples were sintered at a temperature of 850 °c for 8 hrs for heating rate of 2°c/min and soaking time of 120 min. fig. 1. shows the sintering temperatures against the time for sintering. it is observed that the almost densification occurs at a sintering temperature of 850°c. figure 1. heat treatment cycle in the sintering process. 120 kadhim n. abid et. al /al-qadisiyah journal for engineering sciences 12 (2019) 118–126 2.3. physical and mechanical testing the samples were examined by the following devices: 1x-ray diffraction analysis was carried out at the geology department, college of sciences, university of baghdad. the xrd analysis was performed at a wavelength of 1.54060 (a) using the cu kά x-ray source and 2θ range from 30° to 90° with voltage 40.0 (kv). xrd was used to determine the phases of the samples and their types (bruker) and scan rate (speed) 5-10° min. 2sem and edx analysis electron microscopy scanner (t scan) has been used to study the structure of microparticles by using scanning electron image type (vega3 lum) and energy dispersive x-ray spectroscopy (eds) type (oxford max3) to obtain a primary characterization of the materials. the analysis was performed at the university of technology / department of production engineering and metallurgy. 3according to archimedes rule, bulk density, apparent porosity & water absorption were tested using standard (astm c373-88) and a sensitive electrical balance (sartorius) with an accuracy of 5 digits. 4compressive strength to perform the test (microcomputer controlled electric universal testing machine was used to evaluate the compression strength of the prepared materials by returning to standard astm e9-89. the machine has the capacity that does not exceed 180 kn . 5electrical and thermal conductivity electrical and thermal conductivity of samples was examined at the university of baghdad, college of education ibn-alhaytham for sciences of drainage in the service laboratory. 6 hardness samples were measured using the micro vickers method by a device (digital micro hardness tester). according to the astm e-384-11, and using a load of 1000 g for 10 sec. table 1. chemical composition of matrix material (bypass cement dust) and reinforcement materials materials sio 2 % fe 2 o 3 % al 2 o 3 % tio 2 % cao% mgo% so 3 % loi% na 2 o% k 2 o% cl% total% bypass cement dust 13.14 1.49 3.70 0.14 43.00 3.90 2.900 27.90 0.87 1.02 0.99 99.05 marble 0.27 0.09 0.17 0.01 54.17 1.28 0.010 43.90 0.04 0.01 <0.02 99.96 granite 76.18 3.24 6.84 0.30 1.00 0.18 0.020 0.68 4.09 7.41 0.02 99.96 table 2. percentage of matrix material (bypass) and reinforcing materials sample bypass wt% granit wt % marble wt% silica wt% a5 38% 30% 0 32% b4 59% 0 25% 16% c5 28% 30% 10% 32% 3. results and discussion 3.1. xrd analysis fig. 2. shows the formation of crystalline phases for the sample a5 after thermal treatment. the titanite is formed due to the combination of oxides (tio, sio2, cao), which leads to complex composite ( catisio5) (31.9%) , causing an improvement in the hardness [9]. the formation of wollastonite (casio3) (19.9%), is produced by the combination of cao with sio2 which improves the performance parameters due to its fluxing properties, freedom from volatile constituents, whiteness, and the acicular particle shape and decreases shrinkage. also, the formation of diopside mgcasi2o6 (16.9%) is formed as one of the main crystalline phases in glass ceramic. the formed compound si2o4 (29.4%) is a condensed phase, which consists of clusters of extremely small particles, these particles are covalently bound, which is responsible for decreasing thermal and electrical conductivity, due to covering the sample by mantle. periclase mgo (1.7%) is an important material generally used in refractories manufacturing because of its low thermal expansion coefficient, excellent chemical stability, and resistance to thermal shock. increasing the crystal form of periclase helps to remove any holes , porosities or any cracks formed due to shrinkage and other thermal expansion [9]. fig. 3. shows the formation of crystalline phases of pyrochlore (ca2ti2o6) (42.1%) on the sample b4 after thermal treatment , which improves the thermal insulation property of the material. the formation of anorthoclase ((na,k) (alsi3o8) (19.5%), which is a crystalline solid composite improves the hardness of material [11]. the diopside mgcasi2o6 (17.5%) is formed as well, which is one of the main crystalline phases of producing glass ceramic. the properties of sample b4 is better than sample a5 because of the high percentage of diopside in b4. the percentage of periclase (10.4%) in b4 is greater than its value in a5. figure 2. xrd pattern of a5 sample kadhim n. abid et. al /al-qadisiyah journal for engineering sciences 12 (2019) 118–126 121 figure 3. xrd pattern of the b4 sample. fig. 4 shows the formation of crystalline phases for the sample c5 after thermal treatment. these phases are wollansite (38.3%), quartz (29.6%), titanite (24.0%), calcium hexaaluminate (3.6%) cristobalite (3.4%) are formed except diopside and periclase . however, diopside is one of the main crystalline phases in glass ceramics [12] beside periclase in spite of its low percentage, so that sample a5 represents glass ceramic material in large extent as a compared to the sample c5. in addition to that c5 sample contains a high percentage of sio2 and cristoballite which is a high-temperature polymorph of silica, meaning that it has the same chemical formula as quartz, sio2, but a distinct crystal structure. both quartz and cristobalite are polymorphs with all the members of the quartz group [12]. figure 4. xrd pattern of c5 sample 3.2. sem & eds analysis figs. (5,7 and 9) show the sem images of the prepared samples. the crystallization starts from the external surface toward the inside region. in a5 sample diopside crystal began to grow as thin needles from the surface of the glass ceramic specimen towards the centre. it shows also the formation of the needle like structure, showing skeletal herringbone structure which represents diopside [11]. in the c5 sample, the bladed circular wollastonite is changed to the texture in glass ceramic sample from rough (coarse) to soft (fine) particles which may attribute to increasing in viscosity due to increase in the content of sio2% and cao%. the results show that the presence of mgo and catisio5 in glass ceramic will increase the tendency of bulk crystallization of glass ceramic. ca+2 ions likewise are responsible for bulk crystallization in both a5 and c5 samples. the result of a possible change in the coordination state of ca+2 ions in silicate glass ceramic has been subject to considerable debate. the result of a possible change in its coordination state is from cubic to octahedral structure. the coordination states depend, to some extent, on alkalinity or basicity of silicate. the ca+2 ions would, therefore, exist in both six-fold coordination (octahedral) in wallastonite and eight-fold coordination (cubic) in titanite in sample a5. in sample c5 both eight-fold coordination (cubic) in wollastonite and six-fold coordination (octahedral) in titanite are observed in glass ceramic structure because of increasing the percentage of phases, due to increasing the chemical coordination in silicate glass ceramic material [11-4]. the crystallization in sample b4 is begun by surface and bulk nucleation. crystallization occurs through the entire volume of sample b4. this is desirable for enhancing the crystallization of glass ceramic through bulk nucleation, which tends to form crystalline glass ceramic products. figs. (6,8 and 10) show the eds results of glass ceramic of sample a5,c5, and b4. it is observed that the a5 sample consists of mg, because the sample contains diopside and periclase (mgo), while the sample c5 does not have mg. moreover, fe and s elements are found in a5 sample, while the sample c5 is free from these elements. the amount of fe in sample a5 is greater than its content in sample c5 due to the formation of fe2o3. the mg is included in sample b4, because of the structure of the sample which consists of diopside and periclase. further, ca, ti, na, k, al are involved in the structure due to pyrochlore, mullite, and sillimanite phases. figure 5. sem of a5 https://en.wikipedia.org/wiki/polymorphism_(materials_science) https://en.wikipedia.org/wiki/silica https://en.wikipedia.org/wiki/quartz https://en.wikipedia.org/wiki/silicon_dioxide 122 kadhim n. abid et. al /al-qadisiyah journal for engineering sciences 12 (2019) 118–126 figure 6. eds of a5 figure 7. sem of c5 figure 8. eds of c5 figure 9. sem of b4 kadhim n. abid et. al /al-qadisiyah journal for engineering sciences 12 (2019) 118–126 123 figure 10. eds of b4. 3.3. bulk density fig. 11 shows the variation in bulk density of the sintered materials with the change in the main and the reinforcing contents glass ceramic . it is indicated that the decrease in the percentage of bypass cement dust has led to an increase in bulk density. the density varies with the range (4.57, 4.84, 4.976) g/cm3. the bulk density in a5 sample was increased with increasing the sum percentage of reinforcement material. although, marble was not found in this sample. the increase in density is due to the high calcium oxide content, which is about 43 % of the cement dust, and has a density of 3.35 g/cm3, also sio2 which formed 13.14 % of cement dust for a density of 2.641 g/cm3. furthermore, the reinforcing materials have high density values which are 3.125 g/cm3 and 2.641 g/cm3 for the granite and silica respectively, which may contribute to an increase in density of a5 sample. it is noticed that the bulk density of b4 sample is less than a5 because of absence granite due to increasing the bulk density in b4 in the range (3.766, 3.821, 4.117) g/cm3. it is noticed that the bulk density in sample c5 is greater than the density in b4, while it is less than the density in a5. it is noticed that the bulk density reached maximum value when there is no addition of marble to a5 sample and value of c5 which gives better results than b4 samples. the high density of the samples a5 and c5 are due to the high density of the granite. hence the porosity is not taken into account. as a result, bulk density is lower than, or equal to (in the absence of porosity), true density. this is complying with study in [12], which explains the reason for increasing the density of sample a5 due to the presence of cement dust and granite at a high percentage. in addition, the sintering of the compress reduced the size of the spaces between particles. this conclusion does not agree with [13] where the compositions due to powder metallurgy where the density decreases with the decreases of the reinforcement materials because increasing porosity. figure 11. relationship between the bulk density and the percentages of main & reinforcing particle contents after the sintering process. 3.4. apparent porosity fig. 12 shows the relationship between the percentages of the main contents of glass ceramic and apparent porosity after the sintering process. it is noticed that the decrease in the percentage of the cement dust has led to decrease in the porosity within the range (0.740, 0.731, 0.656)% in sample a5 when the percentage of bypass cement dust 38wt%. the porosity in sample b4 is decreased within the range (0.983, 0.952, 0.832) % with increasing the percentage of bypass cement dust to 59 wt%. the porosity in sample c5 is varied as following (0.763, 0.820, 0.857%)which is less than the porosity values in sample b4. however, the porosity in sample c5 is greater than porosity values in sample a5. fig. 12 also shows the variation in apparent porosity with the reinforcing materials (granite, marble, and silica) after the sintering process. the percentages of reinforcement are 41%, 62% and 72% for samples b4, a5, and c5 respectively. it is noticed that the increase in the percentages of the reinforcing materials has led to decrease in the porosity within the same range. on the other hand, if the quantity of the reinforced material reduced, the apparent porosity will increase . it is noticed that the samples a5 and c5 have fewer porosities, although they have 62 wt% and 72 wt% percent of the reinforcement materials in the absence of marble in a5 because the high density for the crystallization of the phase formed in a5 and c5. in general, when the density increased the porosity will decrease. also, the crystallization occurred due to sintering will reduce the porosity because the lowering of vacancies between crystals which leads to improving microstructure of the material developed [14]. for sample b4, the porosity is increased because of the decrease in density due to the absence of granite which has the highest density. 124 kadhim n. abid et. al /al-qadisiyah journal for engineering sciences 12 (2019) 118–126 figure 12. relationship between the apparent porosity and the percentage of main & reinforcing particles contents after the sintering process 3.5. water absorption fig. 13 shows the relationship between the percentages of the has and reinforcing contents of glass ceramic and water absorption after the sintering process. it is seen that the decrease in the percentage of bypass cement dust with increasing in the percentages of reinforcing material to 62 wt% in absence marble has led to decrease in water absorption ability in sample a5 within the range (0.310, 0.218, 0.212)%. it is detected that the increase in the percentage of bypass cement dust and decreasing in the percentages of reinforcing material to 41wt% in absence granite has led to decrease in water absorption ability in sample b4 within the range (0.425, 0.423, 0.421)%. it is noticed that the decrease in the percentage of bypass cement dust will increase in the sum of percentages of reinforcing material to 72 wt% led 56 wt% to reduce water absorption ability in sample c5 within the range (0.312 , 0.230 , 0.221)% which is less than water absorption in b4 and it is greater than water absorption in a5. the reason is due to the same reasons mentioned in the apparent porosity where the high temperature of the gradual sintering which leads to evaporation of the substance pva which is used in the compression process. it is noticed that the water absorption of samples a5 and c5 are less than sample b4, this is can be rationalised to the increase in the amount of reinforcement, which reduces the free spaces in material, leading to lower water absorption [14-15]. figure 13. relationship between the water absorption and the percentages of main & reinforcing particle contents after the sintering process. 3.6. hardness fig. 14 shows vickers's hardness in samples c5 and a5 greater than hardness of b4.the reason for the increased hardness in a5 and c5 is the phases that were formed after sintering process and indicated in the xrd and described previously. these phases (diopside mgcasi2o6),(wollastonite casio3) ,(periclase mgo), (titanite catisio5), (quartz sio2),(cristobalite sio2). because the sample a5 contains diopside and titanite which have high hardness and also the sample c5 contains wollastonite ,cristobalite, quartz, and titanite, which have high hardness. it noticed the hardness of c5 a little more than a5 because absence the marble from the a5 led to reducing hardness. although b4 has good hardness, less than a5 & c5 samples. so that samples a5 and c5 comply with the properties of glass ceramic [14-16]. these phases were formed during the sintering process, causing very strong coherence between the particles to produce a rigid body with high vickers hardness. figure 14. relationship between the hardness and the percentages of main & reinforcing particles contents after the sintering process 3.7. compressive strength fig. 15 shows the change in compressive strength with the content for reinforcement. the compressive strength in c5 is greater than b4 and a5 because the c5 sample contains high percentage of reinforcing material, which has worked as a barrier to the growth and progress of the cracks, and thus gives a good resistance to distortions which tends to the production of coherent particles within the samples of high compressive strength. on the other hand, the high sintering temperature tends to increase the adhering between the particles and minimize the pores and void space between them which is also increased the compressive strength [14]. figure 15. relationship between the compressive strength and the percentages of main & reinforcing particles content after the sintering khaled al-farhany /al-qadisiyah journal for engineering sciences 12 (2019) 000–000 125 3.8. electrical conductivity fig. 16 shows the changes in electrical conductivity with the content of reinforcement. the electrical conductivity of b4 is greater than the electrical conductivity of sample a5, because of the presence of pyrochlore (ca2ti2o6) phase (42.1%) in b4 which has low electrical conductivity. it is observed that the electrical conductivity of c5 is greater than electrical conductivity of sample a5. however, it is less than the conductivity of sample b4. a5 sample is better than c5 and b4 because a5 contains si2o4 which form condensed phases called clusters consisting of exceedingly small particles that are covalently bound and responsible for decreasing thermal and electrical conductivity, due to the formation of mantle covered the sample. the decrease in electrical conductivity may be attributed to an increase in the interfacial area due to the decrease in the average grain size [17]. another reason for the decreasing in electrical conductivity is due to ionic – covalent bonding which does not form free electrons. the covalence resulted from the sharing of the two electrons in the outer shell of ca and mg atoms which are found in wollastonite and diopside, i.e. formation of immobile divalent alkali earth ions which block and occupies the interstitial sites and thus reduce the mobility of the alkali ions. the electrical conductivity of glass ceramic highly depends on temperature. at room temperature, the mobility of ions is very small, while it increases with raising temperature [17]. figure 16. relationship between the electrical conductivity and percentages of main & reinforcing particles content after the sintering process. 3.9. thermal conductivity fig. 17 shows the variation in thermal conductivity with the content of reinforcement. the thermal conductivity of samples b4 and c5 are greater than the thermal conductivity of sample a5. this is attributed to including si2o4 in sample a5.this helps to form condensed phases called clusters consisting of exceedingly small particles which are covalently bound and responsible for decreasing thermal and electrical conductivity. further, a layer from mantle may form on the sample, causing decrease in conductivity. heat transport in dielectric solids like glass ceramic depends on the elastic vibration of the lattice, which has a limited effect due to internal boundary scattering. the addition of bypass cement dust and reinforcing materials increase crystal complexity which tends to increase the limitation of the effect of boundary scattering and lower the heat transport, that means low thermal conductivity [18]. figure 17. relationship between the thermal conductivity and percentages main & reinforcing particles content after the sintering process 4. conclusions 1compressing powder of the samples under a load of 15 ton/cm2 is ideal to produce appropriate samples for testing . 2the sintering process occurred at 850 °c for 8 hours produced appropriate samples that have suitable properties and undergoes phases formation. 3increase the bulk and apparent density, hardness, compressive strength and reduce the porosity, water absorption, electrical and thermal, therefore, it is noticed the samples a5 and c5 better than b4. 4there is a possibility to use bypass cement dust from al-kufa cement factory for the production of glass ceramic. references [1] prof. dr. basudeb karmaker : 'functional glass and glass ceramics processing, properties, applications' 2016, kolkata, india. 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[18] c.kitted, michael-stefan rill. introduction to solid state physics department. january 20,2003. [19] junki, nakogawa et, al "crystal structure dependent thermal conductivity photonic crystal mono structures", university tokyo 2000. template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 345 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. microstructure and mechanical properties of homogenized stir casting aluminum bronze alloys prof .dr.sami abualnoun ajeel department of production engineering & metallurgy, university of technology, baghdad, iraq samiabualnon2@yahoo.com asst. prof. dr. rabiha s. yaseen department of production engineering & metallurgy, university of technology, baghdad, iraq rabihazw@yahoo.com asaad kadhim eqal department of production engineering & metallurgy, university of technology, baghdad, iraq asaadka77@gmail.com abstract: in demand to the industrial needs to produce cu-al alloys with controlled chemical compositions. the present research focuses on the production of cu-al alloys with different aluminum additions of 1.9, 3.6, 5.8 and 7.7 wt. % by stir casting method in argon atmosphere. then, homogenized treatment was done for these alloys at 850 oc in different periods of soaking time of 2, 4, and 6 hrs to determine the best conditions for increasing the mechanical properties. this is carried out in the α phase region. the microstructure of the samples is analyzed by using optical and scanning electron microscopy (sem) with (eds). the results showed the mechanical properties of copper were increased with increasing in aluminum content. the microstructure of the castings consist of the dendiritic structure, columinar grains and segregation. the results showed that after homogenization, the microstructure changed to fine grains, elimination of the columnar segregation and the clusters disappeared. the xrd results show that the phases are α (cu-rich) phase as highest peaks and the small amount of cual2 phase. the best aluminum content value was 7.7 wt % and the soaking time 4 hrs were given the high hardness 204 hv and the highest ultimate tensile stress value of 383.8 mpa. . keywords: aluminum bronze, stir casting, homogenization, soaking time, microhardness al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 346 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. introduction aluminum bronzes alloys, copper-based alloys with aluminum as the major alloying element, are of great interest because of its excellent physical and chemical properties, good corrosion resistance and low material cost [1]. these alloys are important for many industerial applications such as railway, aviation, and marine application. also, other applications in which theses alloys are used for example the general water supply, oil and petrochemical industries, specialized anti-corrosive. the range of applications depends on the addition of al element which is usually in the range of 5% 14% [2]. this leads to solid solution strengthening in the cu-al alloy since the al element increases dislocation density during the deformation twinning process [3,4]. cu-al alloy is produced by the casting process which is considered most economical method for obtaining a part of any desired composition, or by any size from a few millimeters. in order to achieve good hardness and mechanical properties, the eutectic cu-al as intermetallic compound should be modified and heat treated. the production of cu-al has been the subject of many investigations. these investigations, however, have focused on al addition more than 9wt% and in two phase region. for instance, gupta et al. investigated the effect of solution treatment and aging on the hardness of cu9%al 6%ni 5%fe aluminum bronze. increase in hardness of the alloy has been reported from 212 hb to 362 hb due to the formation of β phase that is formed during quenching of solid solution and segregation of fine intermetallic in the aging process [5]. similarly, peter salma, et al. investigated the influence of annealing, quenching, and aging on the microstructure and mechanical properties of the cu10al5ni4fe alloy. he compared his results with high-alloyed cu14al5fe aluminum bronze, where the high hardness and wear resistance are imparted due to the β + ɣ phases [6]. abdul hameed khan et al. has also found increased in hardness to 300 hv by aging at 300 oc at 2 hrs, and tensile stress became 620 mpa. when he studied the production of aluminum bronze (cu-10al-3fe alloy) [7]. achiţei et al. used stir castings to produce cu7al3mn aluminum bronzes. the researcher concluded improvement of the mechanical properties and hardness by heat treatment such as homogenization for 2 to 3 hours, quenching in water and tempering [8]. from above it is found that the mechanical properties of aluminum bronzes can be improved with heat treatments, that play an important role in controlling these properties and microstructural features of al bronzes [9,10]. many researchers have been used the cu-al alloy with the addition of 10 wt% or more of al content in the twophase region. also, it is found lacking of studies that cover the study of (fcc α-phase region) alloys. in the present work, the stir casting process and homogenization with various times are adopted to study the influence of aluminum element addition with (fcc α -phase region) alloys on microstructure and mechanical properties that are useful in the marine application al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 347 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 1. materials and methods 1.1 materials used the materials that used in this work are pure copper and pure aluminum analyzed by icp-aes in ibn sina factory that listed in table 1.the raw materials were cut to small pieces with dimensions of (20x20x20) mm in order to simplify melting materials in stir casting. table 1: the analytical chemical composition of the materials 1.2 description of stir casting methods the stir casting is carried out by using system consisted of induction furnace, graphite crucible and drill with speed about 600 rpm by graphite impellers as shown in detail in figure 1(a, b, d, and e). cast iron mold is with two holes diameter 10mm and 16 mm as shown in figure 1 (b). the meseaured devises that used in this study were optical microscope (om) observation, microhardness test using a digital micro vickers hardness tester th714 of (300) g load, and xrd using a shimdzu 6000 x-ray diffraction target cukα1 radiation with 2θ angle covered from 15 to 120 degrees. scanning electron microscopy (sem) is used to investigate microstructures. energy dispersive spectroscopy (eds) is used to identify elements and other microstructural features. figure 1: (a) cup to inert gas, (b) cast iron mold, (c) stir casting system (d) stirring with graphite crucible, (e) argon container. alloy cu al ag fe p mn pb si cu 99.78 0.127 0.05 0.046 0.001 al 99.811 0.047 0.073 0.033 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 348 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. infrared thermometer is used to measure the molten metal temperature and heraeus hanau furnace was used of the homogenization treatment with argon atmosphere as shown in figure 2 (a, b). figure 2: (a) homogenization furnace, (b) thermometer infrared. 1.3 plan work and proceduer of the stir casting the system of stir casting methods is used to melt material with a melting temperature at 1120 0c. the process is started with the preparation of the charge containing the required quantities of elements cu and al. stir casting method with argon atmosphere was used for producing the samples in this study. the preheat of casting molds for about (100–150)°c before pouring is very important to minimize the casting defects such as shrinkage cavities [12]. the raw material was measured using the weighing balance with the accuracy of 0.001. these elements are melted by the induction furnace, after five minutes, the melt was stirred vigorously to ensure the aluminum is dissolved in a crucible. the melt surface covered with fluxes are usually based on borax, due to the ability to dissolve and collect objectionable oxide and makes it possible to obtain a structure free from non-metallic solids. 1.4 effect of heat treatment process on alloys homogenization is a process that used to remove the dendritic and coarse structure from the ingots, in addition reduction imbalanced distribution obtained during the solidification process. the heat treatment that used in this work is homogenization at 850 oc at different soaking time of 2, 4, and 6 hours, followed by water-quenching for all casts to obtain structure homogenization. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 349 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 1.5 sample preparation the diameter and the length of the ingots are 16 mm and 120 mm, respectively. the ingots are cast as rods as shown in figure 3 (a). these materials are cut to specimens with dimension 5mm length and 16mm diameter as shown in figure 3 (b). the tensile test samples prepared using a turning machine according to astm e8m to identify mechanical properties as shown in figure 3 (c). these samples are grinded, polished as shown in figure 3 (b). in addition, etched by keller reagent (5 g fecl3, 95 ml methanol, 5 ml hcl) in order to reveal the microstructure and microhardness. figure 3: (a) the rod casts, (b) cutting rods to small sample and (c) tensile test sample 2. results and discussion 2.1 study of al addition on microstructure the columnar (dendritic) microstructure of α-cu in aluminum bronze alloy is noticed in the all untreated specimens that are produced by stir casting methods. during solidification in the cast iron mold, differences in composition between the melt and solid phase cause the distribution of the aluminum elements in the interior of the dendritic microstructure of copper. figure (4) (a, b, c, and d) indicates the microstructure of as-cast of cu-al alloys containg different amounts of aluminum which are examinned. the microstructure features have consisted mainly of crystals α solid solution with face-centered cubic lattice and the cual2 phase as intermetallic compound on the grain boundary or between dendrite arms [20]. the difference in the secondary dendrite arm spacing of α-cu solid solution and the size of eutectic cual2 with increased of al additions from 3.6 to 8 wt % al. this is because the copper lattice is able to dissolve a certain amount of atoms al element. these atoms take the lattice sites of copper atoms which are called solid solutions strengthening [21]. all these phases are identified by xrd analysis as shown in figure (8). al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 350 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: optical microscope of cu-al alloys shows the columnar and dendrite α phase solid solution as cast at magnification 100x and 200x, (a, b) cu5.8al, (c, d) cu7.7al. 2.2 study of homogenization on microhardness of alloys figure 5 (a, b, c and d) shows the equiaxed grains in the microstructure of these specimens that homogenized at 850 oc for 2, 4 and 6 hrs due to relieve the cast structures and the elimination of the dendrite structure [19]. the analysis of the results shows that the hardness tends to increase with increasing the aluminum content, as well as the hardness will also increase with increasing the time of soaking for the homogenization. figure 6. show that the best hardness value is obained at the soaking time of 4 hrs. it is obvious that the hardness of the samples increases as the al content increased. the hardness of the sample in 4 hrs increased from 76 hv to 204 hv after the homogenization process at 850 oc when the aluminum content increase from 1.9 to 7.7 wt %. this is due to the differences in composition are equalized in some alloys by long-time homogenization as a result of diffusion processes taking place in the solid phase [16]. in addition, the change in the dendrite structure to equiaxed grain has occurred during the homogenization process [17, 18]. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 351 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 5: optical microscope of cu-al alloys (a, b) cu5.8al and (c, d) cu7.7al, shows the equiaxed grain after homogenization 850 c for 4 hrs at magnification 100x and 200x. figure 6: micro hardness of cu-al alloys at different soaking time of homogenization at 850 0c . the sem images in figure 7(a and b) of cu-al alloy show lower amount of defect of porosity and inclusion in microstructures of homogenized specimens at 850°c for 4 hrs. eds analysis for 7.7 % wt al of aluminum al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 352 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. bronze alloy specimen is expected to contain more dissolved aluminum as solid solution in the copper matrix as shown in figure 7(c and d). figure 7: microstructure of cu-al alloy (a and b) sem images of cu7.7al and (c and d ) eds of cu al alloy that homogenized at 850 0c for 4 hrs. intermetallic phase of the cast alloy is determined by xrd using cukα1 radiation. the 2θ angle covered is from15 to 100 degree. xrd analysis is performed in the specimens showing strong peaks of the cu-rich α phase. the smallest peaks of the eutectic cual2 phase as intermetallic compound that formed in the matrix as shown in figure 8. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 353 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 8: shows xrd using cu k α radiation peaks of cu-al alloy, homogenized 850 oc for 4 hours. 2.3 tensile test figures 10 represents the stress-strain diagram for all samples that homogenized at 850 oc for 4 hrs soaking time. it explains a significant increase in ultimate tensile and yield strengths with increase al content. in this figure, when the al content increased from 1.9 to 7.7 wt% the ultimate tensile and yield strengths change from 175 mpa to 383.8 mpa and 38.97 mpa to 175.38 mpa respectively. in addition was observed the increase in hardness from 48.67 hv to 204.13 hv with an increase in al content as shown in figure (11). the high strength and hardness accompanied by an increase in strain. figure 10: the stress-strain curves with al content of cu-al alloy that homogenized at 850 0c for 4 hours this is due to the interactions of grain boundary strengthening, strain hardening, and obstacle the dislocation movement during the deformation that occurs in the tensile test. avoiding the coarse precipitates and redistributing during solidification of the alloying elements is consider the main reason for the al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 354 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. improvement of the mechanical properties of the alloy[22]. from figure (11) the decrease in elongation from 21.42% to 11.19 % was observed with an increase in al from 1.9 to 3.9 wt% due to strain hardening. whereas the percentage of elongation slightly increase from 11.19 to 26.90 wt % with an increase in al from 3.9 to 7.7 wt% due to grain boundary sliding becomes the major deformation mechanism. figure 11: ultimate tensile strength, yield strength, hardness and elongation with al content of cu-al alloy that homogenized at 850 0c for 4 hrs. conclusions the effects of al content and heat treatment on the mechanical properties of the aluminum bronze alloy were investigated. the results showed changes in microstructure. the dendrites microstructure was changed to equiaxed grains that were formed after homogenization. these changes were contributed to improve in the mechanical properties such as ultimate tensile stress and yield stress whereas the elongation was slightly increased due to domination grain boundary sliding on the deformation mechanism. it also indicated that solid solution strengthening occurred owing to the increase in al content. the increasing in al content led to increase in hardness values of samples due to the formation of α solid solution phase that causes solid solution hardening. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 355 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. references 1. wang, huang; and xie, "enhanced room-temperature tensile ductility of columnar-grained polycrystalline cu–12wt.% al 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(872-876). 22. mohammad baghani; mahmood aliofkhazraei; and mehdi askari, “cu−zn−al2o3 nanocomposites: study of microstructure, corrosion, and wear” international journal of minerals, metallurgy and materials volume 24, number 4, 2017, pp.(324462). article al-qadisiyah journal for engineering sciences 14 (2021) 109–116 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mech.post04@qu.edu.iq (duaa y.haran) https://doi.org/10.30772/qjes.v14i2.752 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. application of les/pdf and rans/pdf approaches for simulation of spray combustion duaa y. haran a* and ahmed a. majhool a a department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq. a r t i c l e i n f o article history: received 14 april 2021 received in revised form 6 june 2021 accepted 13 june 2021 keywords: spray combustion eulerian/lagrangian turbulence model fluent a b s t r a c t this paper is addressing of a coupling large-eddy simulation (les) and rans turbulence models with mixture fraction/probability density function as a combustion model. the two models have been implemented to simulate ethanol-air spray combustion. the gas phase is described with the eulerian approach while the liquid phase is designed using a lagrangian framework. the les/pdf approach is obtained statistically. the sub-grid scale energy equation is used with the les/pdf approach. the numerical results are validated with experimental data. both les/pdf and rans/pdf approaches are compared with the experimental data. the les/pdf approach shows a good agreement in predicting the average gas temperature compared with rans/pdf approach. the les/pdf shows a better prediction of both turbulence intensity profiles and the vortices which are generated in the turbulent flow in comparison with the rans/pdf approach. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction liquid fuels are widely used in industrial combustion systems like the internal combustion engine, liquid-fueled rockets, and gas turbine. it plays a significant role in our energy supply. typically, liquid fuels are provided as a turbulent spray into the combustion chamber. the efficiency of combustion, stability, and pollutant formation depend heavily on the turbulent spray characteristics[1-6]. therefore, attention must be paid to understand the mechanism of turbulent spray combustion and developing methods that would give a clearer picture of the behavior of such phenomena. modelling and the numerical simulation are considered a challenging because it involves complex processing such as turbulence, phase change, heat transfer, and chemical reactions. in recent years, largeeddy simulation of liquid spray combustion has received a lot of attention. les can provide more accurate statistical results and detailed dynamic flow and flame structures compared to reynoldsaveraged modelling (rans). in the future, it is predicted that the les turbulence model will become a widely used computational fluid dynamics method that will replace rans modelling[7, 8]. there are many pieces of research in les of the turbulent two-phases flow and the liquid spray combustion were reviewed by the current authors. jones et al. [9] cfd simulation of swirl stabilized flames fueled by liquid kerosene were provided by large-eddy simulation (les). there were two flames studied for which experimental data was available. flame (a) was a stable flame, while flame (b) was unstable due to its lower air fuels ratio. the results of a combined les/ pdf technique were applied to high swirl reacting spray flows and compared to empirical data. the formulation took into account sub-grid turbulence-spray-chemistry interactions, as well as the coupling between the gas and liquid phase. dodoulas et al. [10] three pre-mixed piloted turbulence ch4/air flames at different reynolds numbers were subjected to large-eddy simulation/filtered density function model. in contrast to experimental data using the same closures used in non-premixed combustion with no changes to the combustion regime, the results showed strong agreement. the effect of heat release on the flow domain was http://qu.edu.iq/ mailto:mech.post04@qu.edu.iq https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 110 duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 investigated and correctly captured. the results showed that pre-mixed combustion could be modeled using les/pdf methods, at least under work conditions, and that approach could reliably capture spray conditions where combustion was not significant and large pockets of extinction emerged. heye et al. [11] the experimental data of a pilot-established ethanol spray flame was analysed using the les/odf method. a lagrangian monti-carlo model was used to solve the pdf equation. the droplet evaporation occurred way from the flame front, separation two processes. owing to the high flow rate of the droplet-laden air, the front flame was unable to propagate. as compared to the others, there were significant differences in the conditions of the droplet inflow. ukai et al. [12] a combined large-eddy simulation (les)/conditional moment closure approach applied to model spray combustion. additional source terms in the transport equation of cmc originating from fuel evaporation were modelled, and their effect on flame structure and global quantities including tentatively averaged temperature profile had been investigated. the laboratory spray jet flame prediction was generally good. the evaporation source term caused a flux in mixture fraction space, which shifted peak temperatures to higher mixture fraction regions. jones et al. [13]in the generic combustor, les was used to simulate kerosene/air. the liquid phase was defined using the eulerian method, which was fully coupled with the lagrangian method. reacting and non-reacting environments were simulated in two separate test cases. in terms of mean statistics and flame structure estimation, the flow field simulations were satisfactory. ukai et al. [14] to model spray combustion, a hybrid largeeddy simulation (les)/conditional moment closure method was used. the cmc method was coupled with a chemistry table that allowed for spatial and temporal variations of the tabulated chemical composition and provided a fair reliable estimation of the chemical source term of the les/filtered reaction development variable. the numerical results were validated with experimental of two dilute acetone spray with preevaporation. an axial spray velocities and temperature predictions were noticeably enhanced, while rms velocity showed reasonable agreement. dodoulas et al. [15] for simulating a non-premixed flame with high extinction, a large eddy simulation/pdf method was used. this method is effective in predicting the local flame extinction at different flame locations, and the major species predictions were found to be in good agreement with the practical data. the flame structure was analyzed by using chemical explosive modes. due to the turbulence combustion model nature, the statistical data on the sub-grid flame structure can be obtainable. sub-grid explosive models, for example. according to the results, sub-grid structures were only essential near the inlet nozzle in the current flame, and downstream extinction was controlled by large-scale interaction. wang et al. [16] on the acetone flame structure, three combustion models (finite-rate chemistry model, flame-prolongation of intrinsic low dimensional manifold model, and flamelet-progress variable model) were applied to achieve large-eddy simulation (les) of a turbulence spray structure. in comparison to experimental results, the use of a finite-rate chemistry model combined with a reduced chemical mechanism results in improved prediction of spray flame structure and heat release among the three models. sacomano filho et al. [17] in the form of a c2h5oh/air turbulence flame, a turbulence flame interaction and evaporative cooling effect were investigated in les turbulence. the artificially thickened flame method (atf) was combined with the mixture adaptive thickening extension technique to account for enthalpy variations. the eulerian/lagrangian system was used to track the droplets. the flamelet-generated manifold method has been tabulated by chemistry (fmg). variations in enthalpy were integrated into the outcomes fgm database in a universal manner that was not limited to heat losses due to evaporative cooling effects. aside from being novel, the proposed modelling strategy’s comprehensiveness allowed for a significant contribution to the understanding of turbulent spray combustion modeling’s most relevant phenomena. [17] as a result of the introduction of renewable aviation fuels, alternative methods and models are needed that can predict the combustor performance based on the fuel composition. in the sense of eulerian/lagrangian les, a multi-component vaporization model was coupled with a direct. the burner which used in this work exhibited some of the existing features of aero-engine combustors like the reaction zone position and measured spray combustion were fine reproduced by les turbulence model. the computational outcomes showed that the evaporation and mixing were the rate-controlling stages in the flame zone. chemistry can be presumed to be significantly fast in this zone. however, other regions existed where the finite rate chemistry influence available. the approach of the finite rate chemistry demonstrated great potential in terms of pollution formation. furthermore, the formation of benzene from one specific chemical form in the fuel suggested that to accurately predicted soot emissions, multi-component explanation of the liquid phase and the evaporation process was needed. paulhiac et al. [18] a spray-swirled burner was subjected to les/discrete particle simulation. there are two types of validation: reacting and non-reacting. the velocity field of the two-phases finding was consistent in both cases as compared to experimental data. the les grid fails to describe the non-premixed flame set near the droplets due to direct interaction between the spray and flame. instead, the current model referred to pre-mixed combustion, which allowed for a percentage error on both the burning rate and combustor efficiency. it was necessary for using a single droplet combustion model which is appropriated to the les/dps framework. [18] spray reactive flow is used in a variety of technological instruments. a sub-grid scale combustion model is studied. two different flamelet methods were implemented which were consisting of spray flamelet and multi-regime gas flamelet models. the numerical evaluation was implemented in largeeddy simulations (les) of a benchmark c2h5oh/air spray flame a partial pre-vaporization. an eulerian/lagrangian numerical framework was adopted. outcomes showed that the spray flamelets developed from counterflow partially-premixed spray flames showed a better agreement with the experimental data. in the present work, ansys fluent is applied for simulating two-phase flow in 2d, free shear stress with a certain domain 360mm×460 ge et al. [19]. large eddy simulation (les) and reynolds averaged navier-stokes equations (rans) turbulence model are amplemented to simulate the turbulent spray of c2h5oh/air spray. both turbulence models are combined with a probability density function (pdf) as a combustion model. then used for investigating using various parameters in an attempt to find out which of approach is the best in giving results closer to the practical results and closer visualization of the practical reality. 2. governing equations the main physical processes of down-draft evaporative cooling consist of turbulent flow, species mixing, mass, and heat transfer. differential equations for each species, mass conservation, momentum conservation, and energy conservation must be solved. also, the transport equations for the turbulence model should be solved. these equations are employed into three sets, continuous phase (euler phase) equations used duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 111 for solving the fluid flow and species transport, dispersed phase (liquid phase ) calculate the trajectory of the fuel droplets, and due to strong cooperation between two-phases, the coupled effect must be solved for the complex environment. all equations and constants used based on ansys fluent theory fluent et al. [20]. the general equations that are using for the solution identified as following: 2.1. euler phase model fluent ansys solves gas-phase flow as well as analysis the differential equations of mass conservation, momentum conservation, energy conservation, and species. in the initial stages of the process, the model solves the gas-phase without including the interaction between two phases, when the liquid phase (disperse particle) trajectories are solved, and the source terms are added [20]. fluent solves gas-phase with consideration of the source terms in the numerical calculations. the conservation mass equation is 𝜕 𝜕𝑥𝑖 (𝜌𝑢𝑖 ) = 𝑆𝑚 ( 1 ) where ( 𝑢𝑖 ) is the air velocity component in euler-phase (m/s), 𝑆𝑚 defined as an additional mass to gas-phase from liquid-phase (discrete phase) (𝑘𝑔/𝑚3𝑠 ). the transformation momentum due to the exchange can be expressed: 𝜌𝑢𝑖 𝜕𝑢𝑖 𝜕𝑥𝑗 = 𝜕 𝜕𝑥𝑗 [𝜇 ( 𝜕𝑢𝑖 𝜕𝑥𝑗 + 𝜕𝑢𝑗 𝜕𝑥𝑖 ) − 2 3 𝜇 ( 𝜕𝑢𝑗 𝜕𝑥𝑗 ) 𝛿𝑖𝑗 ] + 𝜌𝑔𝑖 − 𝜕𝑝 𝜕𝑥𝑖 + 𝐹𝑖 (2) when the species diffusion and the source due to the energy interchange between phases are included, the energy equation is identified in the following part (),where 𝑆𝑛 is the volumetric heat source (𝑘𝑔/𝑠 3𝑚), the heat transfer is calculating by using: 𝜌𝑢𝑖 𝜕𝑒 𝜕𝑥𝑖 = −p ∂u𝑖 ∂x𝑖 + φ𝜐 + 𝜕 𝜕𝑥𝑖 (𝑘 𝜕𝑇 𝜕𝑥𝐼 ) + 𝜕 𝜕𝑥𝐼 (∑ ℎ𝑖 𝐽𝑖 𝑛 𝑖=1 ) + 𝑆𝑛 (3) where 𝜇 is the molecular viscosity ( 𝑘𝑔/𝑚2𝑠2 ), 𝐹𝑖 is the momentum source (𝑘𝑔/𝑚2𝑠2), 𝑔𝑖 is a gravity (𝑚/𝑠 2), p is the static pressure (pa), 𝑒 is the internal energy (𝐽/𝑘𝑔), 𝑇 is air temperature in (𝐾) , ℎ𝑖 is the species enthalpy, φ𝜐 is the rayleigh dissipation function (𝑘𝑔/𝑠3𝑚) , 𝑘 is the thermal conductivity (𝑊/𝑚𝑘 ), 𝐽𝑖 is the species (i) diffusion flux( 𝑘𝑔/ 𝑚2𝑠). the species conservation equations for predicting the local mass fraction of each phase, i.e., gas-phase of fuel and air, are: 𝜌𝑢𝑖 𝜕𝑚𝑖 𝜕𝑥𝑖 = −𝑃 𝜕𝐽𝑖 𝜕𝑥𝑖 +𝑆𝑚 (4) 𝐽𝑖= − 𝜌𝐷𝑖,𝑚 𝜕𝑚𝑖 𝜕𝑥𝑖 (5) where 𝑚𝑖 is the local mass fraction of specific phase (i) and 𝐷𝑖,𝑚 is the diffusion coefficient for a specific phase (i) in the mixture. 2.2. liquid phase model the discrete droplets in the gas-phase are suggested to be spherical. at the starting of the solutions, the lagrangian approach is used to calculate the trajectory of the particles (discrete phase) by integrating the force balance, while the gas-phase is recalculated and adjusted, it solves the liquid-phase in the following equations: 𝑑𝑈𝑝 𝑑𝑡 = 𝐹𝐷 (𝑢 − 𝑢𝑝) + 𝑔𝑥(𝜌𝑝−𝜌) 𝜌𝑝 + 𝜌 𝜌𝑝 𝑢𝑝 𝜕𝑢 𝜕𝑥𝑖 (6) 𝐹𝐷 = 18𝜇 𝜌𝑝𝑑𝑝 2 𝐶𝐷𝑅𝑒 24 (7) 𝑅𝑒 = 𝑑𝑝𝜌∣𝑢𝑝−𝑢∣ 𝜇 (8) 𝐶𝐷 = 𝑎1 + 𝑎2 𝑅𝑒 + 𝑎3 𝑅𝑒 2 (9) where 𝑢𝑝 is the droplets velocity (m/s), 𝐹𝑑(𝑢 − 𝑢𝑝 ) is the drag force per unit droplet mass (𝑚/𝑠2), (𝑔𝑥(𝜌𝑝−𝜌) 𝜌𝑝⁄ ) is the gravitational force on the droplet, the last term on the right hand of the equation represents the additional force due to the pressure gradient in the fuel, 𝑑𝑈𝑃 𝑑𝑡⁄ is the evaporation rate of the droplet, 𝑔𝑥 is the gravity (𝑚/𝑠 2), 𝐶𝐷 is the drag coefficient, 𝑑𝑝 is the diameter of the droplet (m), and 𝑎1, 𝑎2, and 𝑎3 are constants obtain by morsi and alexander [21]. the heat balance utilizes for computing the heat transfer between the gas-phase and liquid-phase. radiant heat transfer is ignoring, is identified as: 𝑚𝑝𝑐𝑝 𝑑𝑇𝑝 𝑑𝑡 = ℎ𝑓𝑔 𝑑𝑚𝑝 𝑑𝑡 + ℎ𝑝𝐴𝑝(𝑇∞ − 𝑇𝑝) (10) where 𝐴𝑃 is the droplet surface area (𝑚 2), 𝑐𝑝 is the droplet heat capacity ( 𝐽/𝑘𝑔 𝑘 ), 𝑇𝑃 , 𝑇∞ are the temperature of the droplet and gas-phase respectively in (k), ℎ is the convective heat transfer coefficient (𝑊/𝑚2𝑘 ), ℎ𝑓𝑔 is the latent heat of evaporating of fuel (𝐽/𝑘𝑔). 2.3. coupling phases an iterative method is implementing to solve two coupled phases(gas phase and discrete phase). when the computation of the particle stream is done, including the calculation of the gain or loss of mass, momentum, and heat by the particle trajectory, then these quantities are added into the gas-phase (continuous) calculation. the mass exchange between two phases is evaluated as the mass differences between all c.v using. 𝑆𝑚 = ∆𝑚𝑝�̇�𝑝,𝑜 𝑚𝑝,𝑜 (11) where 𝑆𝑚 is the mass exchange, ∆𝑚𝑝 is the change of the particle mass in each c.v, 𝑚𝑝 is the particles mass flow rate, 𝑚𝑝,𝑜 is the mass flow rate of the particle at the initial state. then 𝑆𝑚 included in the mass conservation equation. in addition, the gas-phase is added as a source of mass in the species equation. the momentum transfer between two phases can be calculated as: 𝐹𝑖= ∑ ( 18𝜇 𝜌𝑝𝐷 2 𝑃 𝐶𝐷𝑅𝑒 24 (𝑢𝑝 − 𝑢) + 𝑔𝑥(𝜌𝑝−𝜌) 𝜌𝑝 + 𝜌 𝜌𝑝 𝑢𝑝 𝜕𝑢 𝜕𝑥𝑖 ) �̇�𝑝∆𝑡 (12) the vaporization rate of the droplets is controlled by the concentration of the vapour between the surface of the droplet and gas-phase. 𝑁𝑖=𝑘𝑐 (𝐶𝑖,𝑠 − 𝐶𝑖,∞) (13) 𝐾𝑐= 𝑆ℎ 𝐷𝑖,𝑚 𝑑𝑝 = (2+0.6𝑅𝑒 1 2⁄ 𝑆𝑐 1 3⁄ )𝐷𝑖,𝑚 𝑑𝑝 (14) 𝐶𝑖,∞ = 𝑋𝑖 𝑃 𝑅𝑇∞ (15) 𝐶𝑖,𝑠 = 𝑃𝑠𝑎𝑡(𝑇𝑝) 𝑅(𝑇𝑝 ) (16) where 𝑁𝑖 is the vapour molar flux (𝑘𝑔 𝑚𝑜𝑙𝑒/𝑚 2𝑠), 𝐾𝑐 is the coefficient of the mass transfer (𝑚/𝑠), 𝐶𝑖,𝑠 is the vapour concentration at the surface of 112 duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 the droplet (𝑘𝑔 𝑚𝑜𝑙𝑒/𝑚3), 𝐶𝑖,∞ is the vapour concentration in gas-phase (𝑘𝑔 𝑚𝑜𝑙𝑒/𝑚3), 𝑃𝑠𝑎𝑡 is the vapor pressure at saturated state (pa), 𝑅 is the universal gas constant ( 𝐽 𝑘𝑔⁄ 𝑘 ), 𝑆ℎ is the sherwood number, 𝑆𝑐 is schmidt number, 𝑋𝑖 is the local bulk mole fraction of specific phase 𝑖 . droplet evaporation is submited to law 2 in fluent, and the change of the droplet mass can be found: 𝑚𝑝(𝑡 + ∆𝑡) = 𝑚𝑝(𝑡) − 𝑁𝑖 𝐴𝑝𝑀𝑤,𝑖 ∆𝑡 (17) where 𝑀𝑤,𝑖 is the molecular weight of specific phase 𝑖 ( 𝑘𝑔 𝑘𝑔 𝑚𝑜𝑙𝑒 ), 𝑆ℎ is the volumetric source term, can be expressed as 𝑆ℎ = [ �̅�𝑝 𝑚𝑝,𝑜 𝑐𝑝 ∆𝑇𝑝 + ∆𝑚𝑝 𝑚𝑝,𝑜 (−ℎ𝑓𝑔 + ∫ 𝐶𝑝,𝑖 𝑇𝑝 𝑇𝑟𝑒𝑓 𝑑𝑡)] �̇�𝑝,𝑜 (18) where �̃�𝑝 is the droplet average mass in a control volume (𝑘𝑔) 2.3.1. turbulence model the turbulence model is a mathematical model used to describe the turbulent flow which is commonly used in a realistic and engineering application .turbulence models are used to represent turbulence by using simple equations . in this work standard k-𝜖 and large-eddy simulation are used representing the random and irregular flow. 2.3.1.1. standard k-𝝐 model in the standard model derivation ,flow assumes fully turbulent and ignores influence molecular viscosity .it is appropriate just for fully turbulent. for the turbulent kinetic energy ,𝑘 𝜕 𝜕𝑡 (𝜌𝑘) + 𝜕 𝜕𝑥𝑖 (𝜌𝑘𝑢𝑖 ) = 𝜕 𝜕𝑥𝑗 ⌈(𝜇 + 𝜇𝑡 𝜎𝑘 ) 𝜕𝑘 𝜕𝑥𝑗 ⌉ + 𝐺𝑘 + 𝐺𝑏 − 𝜌𝜖 − 𝑌𝑀 + 𝑆𝑘 (19) for turbulence dissipation rate 𝜖 𝜕 𝜕𝑡 (𝜌𝜖) + 𝜕 𝜕𝑥𝑖 (𝜌𝜖𝑢𝑖 ) = 𝜕 𝜕𝑥𝑗 [(𝜇 + 𝜇𝑡 𝜎𝜖 ) 𝜕𝜖 𝜕𝑥𝑗 ] + 𝐶1𝜖 𝜖 𝑘 (𝐺𝑘 + 𝐶3𝜖 𝐺𝑏 ) − 𝐶2𝜖 𝜌 𝜖2 𝑘 + 𝑆𝜖 (20) where 𝜇𝑡 is the turbulent viscosity modeling as : 𝜇𝑡=𝜌𝐶𝜇 𝑘 2 𝜖 (21) 𝐺𝑘 = −𝜌𝑢𝑖́ 𝑢�́� 𝜕𝑢𝑗 𝜕𝑥𝑖 (22) 𝐺𝑏 is the effect of buoyancy 𝐺𝑏 = 𝛽𝑔𝑖 𝜇𝑡 𝑃𝑟𝑡 𝜕𝑇 𝜕𝑥𝑖 (23) where : the dissemination rate is 𝑌𝑚 , the production of turbulent kinetic energy is 𝐺𝑘 , the turbulent velocity is �́�, the thermal expansion coefficient is 𝛽, the turbulent prandtl number is 𝑃𝑟𝑡 is ,at default = 0.85, the source term defined by used are 𝑆𝑘 ,𝑆𝜖 ,and the reverse active prandtle are 𝜎𝜖 ,𝜎𝑘 for 𝜖 , 𝑘 respectively. constants model at default value are 𝐶1𝜖=1.44 ,𝐶2𝜖=1.92,𝐶𝜇=0.09 ,𝜎𝑘 =1 ,𝜎𝜖 =1.3 ,𝐶3𝜖=-0.33 2.3.1.2. sub-grid scale model energy equation stress model a sub-grid scale equation energy stress model is expressed as 𝜏𝑖𝑗 = 2 3 𝜌𝐾𝑠𝑔𝑠𝛿𝑖𝑗 − 2𝐶𝑘 𝜌𝐾𝑠𝑔𝑠 1 2⁄ ∆𝑓𝑆𝑖𝑗̅̅̅̅ (24) 𝐾𝑠𝑔𝑠 is acquired by solving the transport equation 𝜌 𝜕�̅�𝑠𝑔𝑠 𝜕𝑡 + 𝜌 𝜕𝑢𝑗�̅�𝑠𝑔𝑠 𝜕𝑥𝑗 = −𝜏𝑖𝑗 𝜕𝑢𝑖 𝜕𝑥 − 𝐶𝜖 𝜌 𝐾3 2⁄ ∆𝑓 + 𝜕 𝜕𝑥𝑗 ( 𝜇𝑡 𝜎𝑘 𝜕𝐾𝑠𝑔𝑠 𝜕𝑥𝑗 ) (25) 𝐾𝑠𝑔𝑠 = 1 2 (𝑢𝑘 2̅̅ ̅ − �̅�𝑘 2 ) (26) 𝜇𝑡 = 𝐶𝑘 𝜌𝐾𝑠𝑔𝑠 1 2⁄ ∆𝑓 (27) ∆𝑓 = 𝑉1 3⁄ (28) where the filter size is ∆𝑓, the sub-grid scale eddy viscosity is 𝜇𝑡. the mechanism of the reaction is implemented in one step, the ethanoloxygen reaction is described chemically as 𝐶2𝐻5𝑂𝐻 + 3𝑂2 →2𝐶𝑂2 + 3𝐻2𝑂 for the radiative heat transfer, the p1 model is used −�̅�𝑟 = 𝑎𝐺 − 4𝑎𝜎�̅� 4 (29) where the stefan-boltzmann constant denotes by 𝜎 = 5.67 ∗ 10−8𝐽. 𝐾−1, the absorption coefficient is 𝑎 = 0.1𝑚−1 and the incident flux is 𝐺 which is processed from the equation of the radative transfer. when 𝑎 → 0 ,𝑞𝑟̅̅ ̅ → 0. 2.3.2. combustion model in this research, the probability density function (pdf) was employed to evaluae some combustion properties. obtained from the mixture fraction to provide the effect of the turbulence fluctuation on the quantities of the conserved scalar, two types of probability density function : a clippsed gaussian and beta function. in the present research, a beta function commonly is used for simplicity and lower cost . beta function mathematically identified : 𝑝(𝑓) = 𝑓𝜓−1(1−𝑓)β−1 ∫ 𝑓𝜓−1 1 0 (1−𝑓)β−1𝑑𝑓 (30) 𝑓 = 𝑧𝑖 −𝑧𝑖,𝑜𝑥 𝑧𝑖,𝑓𝑢𝑒𝑙−𝑧𝑖,𝑜𝑥 (31) explicit functions of (𝑓, 𝑔) mathematically described : 𝜓 = 𝑓 [ 𝑓(1−𝑓) 𝑔 − 1] (32) β = (1 − 𝑓)𝜓 (33) species concentration of each product temperature and enthalpy were obtained by weighting the amount of these quantities with depending (pdf ) on mixture fraction ,�̃�(𝑓) . 𝑓,g is calculated using finite difference method for each grid ,𝑄 may be expressed ,where �̌� is the favreaveraging quantity duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 113 �̃� = ∫ 𝑝 1 0 (𝑓)𝑄(𝑓)𝑑𝑓 (34) where a mixture fraction is 𝑓 , mean mixture fraction of mass is 𝑓coefficients of beta pdf are 𝐵 , 𝜓 , the mass fraction for species element i is 𝑍𝑖, the mass fraction for the fuel stream inlet is 𝑍𝑖,𝑓𝑢𝑒𝑙, and the mass fraction for oxidizer stream inlet is 𝑍𝑖,𝑜𝑥. 3. numerical method and condition the computational domain in the present work was a combustor 360× 460 mm shown in fig. 1 in which a c2h5oh/air coaxial diffusion flame can be generated at a pressure of 2 mpa atm [19]. combustor geometry is shown in fig. 2. the optimal grid size of the cells is 83200×167304× 84105 and a quadrilateral refinement shape is implemented. the numerical conditions that were used are summarized in table 1. as mentioned in the introductory part, the probability density function (pdf) is coupled with the large eddy simulation (les) and rans turbulence model which is representing standard k-𝜖 turbulence model. for temporal term, the simple algorithm as a numerical procedure with a secondorder implicit scheme is adopted. for momentum, the second-order upwind is used. for boundary conditions, the inlet velocity of the droplet and the injection angle are implemented according to the experiment[22]. fig. 3. shows the comparison between numerical simulation is using fluent ansys and the measurement. figure 1. the computational domain. figure 2. the spray combustor. table 1. numerical test conditions[𝟏𝟗] [23] parameters units atomization pressure mpa 2 ethanol flow rate g/s 0.47 spray angle computationdomain velocity of inlet air through co-flow the time step of les/pdf ° 𝑚𝑚2 m/s s 45 450×360 0.32 1× 10−6 4. results and conclusion 4.1. results the injection conditions of c2h5oh/air spray combustion are used for validation related to the measurement data taken [19]. the numerical simulation for the spray combustion using rans and les turbulence models. 114 duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 figure 3. gas-phase temperature at different levels when x above the exit nozzle. fig. 3 shows the gas-phase temperature profiles at different levels above the nozzle at 𝑥 = 6 mm, 𝑥 = 10 mm, 𝑥 = 20 mm, and 𝑥 = 25 mm. the measurement is expressed by symbols utilizing multi-line imaging nolif [13]. the dash lines demonstrate the numerical results of (rans) model which is representing the standard k-𝜖 turbulence model coupled with the pdf combustion model. the solid line indicates the numerical results of large eddy simulation (les) coupled with the pdf method. the les/pdf gives an extremely better agreement than rans/pdf approach. the spray flame wings are predicted by the les/pdf approach especially at 20 mm and 25 mm better than rans/pdf approach. according to the outcomes of the experiments, the gradients of the temperature at the flame edge are very high. this phenomenon at section 6 mm is closely predicted by the les/pdf approach, whereas shows a smoother accurately in various point of the experimental data although it predicts the gas-phase temperature at the tip edge of the nozzle is broader than the measurement data. it is important to improve the sub-grid scale combustion model for large-eddy simulation of two phases [16] while rans/pdf in comparison with les/pdf is succeeded in predicting the regions at the tip edge of the nozzle and then the accuracy of the numerical results decreases. in section 10 mm, the numerical results predicted by les/pdf fail in comparison with rans/pdf approach. figure 4. contours plot of simulated gas-phase temperature using rans/pdf, another published work, and spray flame photograph [19],[23]. figure 5. gas-phase temperature in comparison with another published work when x above nozzle at 6 mm [19],[23]. (a) (b) ( c ) figure 6. contours plot of simulated gas-phase temperature and spray flame photograph [𝟏𝟗]. fig. 4 demonstrates the gas phase contours of the numerical simulations that were performed by other authors in comparison with the numerical results of the present work. difference in flame capturing is attributed to many causes such as mesh type, mesh size, numerical method procedure, approaches performance, and anticipating the missing conditions. fig. 5 shows the static temperature profiles of the present work and other authors with the experimental data at x=6 mm above the nozzle. fig. 6 shows a comparison of the reactions zone calculated by the experiment [14] as shown in (a), and the numerical simulation achieved using fluent ansys 19.2 in (b,c). duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 115 rans/pdf les/pdf figure 7. contours plot of the gas-phase temperature at rans turbulence model and les. fig. 7 shows the contours of gas-phase temperature profiles. the coherent structure appears on the right side with les/pdf in which shows the eddy size and energy variation through the domain that can be explained to subgrid scale energy equation model the ability in reinforces the prediction of the small eddies in addition to large eddies which predict by the type of mesh utilizing in comparison to rans/pdf approach. figure 8. mean mixture fraction profiles of reaction zone along with the radial distance. fig. 8 shows a rising in a mean mixture fraction that can be expressed due to the evaporation rate. mixing is relatively higher and the amount of the injected fuel at the nozzle region is higher too in comparison to the oxidizer in this domain. les/pdf approach shows an additional consumption in the fuel in comparison with rans/pdf. fig. 9 shows a gas temperature phase against the mean mixture fraction. there is a low distribution of mean mixture fraction (pdf) confront with the low temperature at the nozzle region and then demonstrate both static temperature and mean mixture fraction rise along with radial distance, especially in the reaction zones when the mixing is done between the ethanol stream and the oxidizer in which the burnt gas created in the upstream and blended with un burnt gas that is resulting in the generation of the high-temperature zone. in comparison, the gas temperature against pdf that is determined by using the les/pdf approach is slightly higher than predicted by rans/pdf approach. figure 9. comparison of predicted gas-phase temperature against mean mixture profiles along with the radial distance. fig. 10 shows the turbulence intensity of gas-phase profiles. at the nozzle region, the turbulence intensity records a high percentage which may be expressed to the turbulence resulting from the hydrodynamic effect, the chemical interaction between two phases, liquid velocity, and the rate of evaporation, then it is eliminated with progressing away from the nozzle region. les/pdf approach with sub-grid scale energy equation shows an additional fluctuation in the turbulence intensity profiles along with the radial distance of the domain which demonstrates the realistic prediction in comparison with the rans/pdf approach. figure 10. comparison of predicted turbulence intensity profiles along with the radial distance. fig. 11 shows the vortices profiles along with the radial distance. in the near and inlet shear stress of the fuel jet flow, the coherent structures are expected to demonstrate and then are concentrated to be large vortices and eventually are weakly in the downstream area that can be predicted by using the les/pdf approach while rans/pdf approach fails in demonstration these phenomena. 116 duaa y.haran and ahmed abed al-kadhem majhool /al-qadisiyah journal for engineering sciences 14 (2021) 109–116 figure 11. comparison of predicted vortices profiles along with the radial distance. 4.2. conclusions the turbulent spray flame of ethanol/air which is studied in this work using two approaches: large-eddy simulation coupled with a probability density function (les/pdf) approach and standard k-𝜖 turbulence model combined with a probability density function as a combustion model (rans/pdf) approach. generally, the statistical results presented that are validated using the les/pdf approach, they show good agreement when compared to the experimental data are better than those acquired by rans/pdf approach, especially in estimating the turbulence intensity profile and vortices. references [1] s. pascaud, m. boileau, b. cuenot, t. poinsot, large eddy simulation of turbulent spray combustion in aeronautical gas turbines, in: eccomas thematic conference on computational combustion, 2005, pp. 149-167. [2] x. jiang, g. siamas, k. jagus, t. karayiannis, physical modelling and advanced simulations of gas–liquid two-phase jet flows in atomization and sprays, progress in energy and combustion science, 36(2) (2010) 131-167. [3] e. gutheil, modeling and simulation of droplet and spray combustion, handbook of combustion: online, (2010) 205-227. [4] f. jaegle, j.-m. senoner, m. garcia, f. bismes, r. lecourt, b. cuenot, t. poinsot, eulerian and lagrangian spray simulations of an aeronautical multipoint injector, proceedings of the combustion institute, 33(2) (2011) 2099-2107. [5] p. senecal, e. pomraning, k. richards, s. som, grid-convergent spray models for internal combustion engine computational fluid dynamics simulations, journal of energy resources technology, 136(1) (2014). [6] n. tanveer, c. mohanraj, k. jegadeesan, s. maruthupandiyan, comparative studies on various turbulent models with liquid rocket nozzle through computational tool, in: advanced materials research, trans tech publ, 2014, pp. 1204-1209. [7] m. chrigui, a. masri, a. sadiki, j. janicka, large eddy simulation of a polydisperse ethanol spray flame, flow, turbulence and combustion, 90(4) (2013) 813-832. [8] n.j. georgiadis, d.p. rizzetta, c. fureby, large-eddy simulation: current capabilities, recommended practices, and future research, aiaa journal, 48(8) (2010) 1772-1784. [9] w. jones, s. lyra, s. navarro-martinez, numerical investigation of swirling kerosene spray flames using large eddy simulation, combustion and flame, 159(4) (2012) 1539-1561. [10] i. dodoulas, s. navarro-martinez, large eddy simulation of premixed turbulent flames using the probability density function approach, flow, turbulence and combustion, 90(3) (2013) 645-678. [11] c. heye, v. raman, a.r. masri, les/probability density function approach for the simulation of an ethanol spray flame, proceedings of the combustion institute, 34(1) (2013) 1633-1641. [12] s. ukai, a. kronenburg, o. stein, les-cmc of a dilute acetone spray flame, proceedings of the combustion institute, 34(1) (2013) 1643-1650. [13] w. jones, a. marquis, k. vogiatzaki, large-eddy simulation of spray combustion in a gas turbine combustor, combustion and flame, 161(1) (2014) 222-239. [14] s. ukai, a. kronenburg, o. stein, large eddy simulation of dilute acetone spray flames using cmc coupled with tabulated chemistry, proceedings of the combustion institute, 35(2) (2015) 1667-1674. [15] i.a. dodoulas, s. navarro-martinez, analysis of extinction in a non-premixed turbulent flame using large eddy simulation and the chemical explosion mode analysis, combustion theory and modelling, 19(1) (2015) 107-129. [16] q. wang, t. jaravel, m. ihme, assessment of spray combustion models in large-eddy simulations of a polydispersed acetone spray flame, proceedings of the combustion institute, 37(3) (2019) 3335-3344. [17] f.l. sacomano filho, l. dressler, a. hosseinzadeh, a. sadiki, g.c. krieger filho, investigations of evaporative cooling and turbulence flame interaction modeling in ethanol turbulent spray combustion using tabulated chemistry, fluids, 4(4) (2019) 187. [18] d. paulhiac, b. cuenot, e. riber, l. esclapez, s. richard, analysis of the spray flame structure in a lab-scale burner using large eddy simulation and discrete particle simulation, combustion and flame, 212 (2020) 25-38. [19] h.-w. ge, i. düwel, h. kronemayer, r. dibble, e. gutheil, c. schulz, j. wolfrum, laser-based experimental and monte carlo pdf numerical investigation of an ethanol/air spray flame, combustion science and technology, 180(8) (2008) 1529-1547. [20] a. fluent, 17.0 theory guide, 2015, canonsburg, pa 15317: ansys, in, inc. [21] s. morsi, a. alexander, an investigation of particle trajectories in two-phase flow systems, journal of fluid mechanics, 55(2) (1972) 193-208. [22] p. lavieille, f. lemoine, g. lavergne, m. lebouché, evaporating and combusting droplet temperature measurements using two-color laser-induced fluorescence, experiments in fluids, 31(1) (2001) 45-55. [23] i. düwel, h.-w. ge, h. kronemayer, r. dibble, e. gutheil, c. schulz, j. wolfrum, experimental and numerical characterization of a turbulent spray flame, proceedings of the combustion institute, 31(2) (2007) 2247-2255. template for academica science journal al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 417 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. study thermal behavior of heat cure poly (methyl methacrylate) reinforced by bamboo and rice husk powders for denture applications jawad k. oleiwi, material engineering department university of technology, baghdad, iraq e mail: jawadkad@yahoo.com qahtan adnan hamad, material engineering department university of technology, baghdad, iraq. e mail: qah84@yahoo.com hadil jabbar abdul rahman, e mail: hadil.jabbar.85@gmail.com material engineering department university of technology, baghdad, iraq. abstract: the present research, studies the effect of adding two different types of reinforcing powders, which included: bamboo (ba) and rice husk (rh), that added with different weight fractions (2, 4, 6 and 8 wt. %), and with the selected size particles of (25µm and 75µm) on thermal behavior of heat cure poly (methyl methacrylate) such as thermal conductivity and thermal diffusivity in addition to the differential scanning calorimetry (dsc) analysis and these tests were accomplished at temperature of laboratory. the poly methyl methacrylate properties which reinforced by (bamboo and rice husk) powders are mainly influenced by the interfacial adhesion strength between the powders and the matrix, and in order to get better correlation between the natural powder and pmma matrix, so the powders were treated with alkali (sodium hydroxide naoh) solution prior to use as reinforcement materials. the results showed that the values of the thermal conductivity and thermal diffusivity increased with increasing of the weight fraction for both particle sizes (25 µm and 75 µm) of natural powders. keywords: acrylic resin, natural powders, bamboo, rice husk, denture introduction science of dental materials is the study of the chemical composition and properties of fabricated and designed materials that are used dentistry field and the manner in which they interact with the environment they are placed in. the most important characteristics of dental material are being biocompatible, non-toxic, non-irritating, non-allergenic, mechanical resistant to fracture, does not deteriorate over time, dimensionally stable, miner change by temperature and solvents. these characteristics vary according to types of dental materials to be used for their intended purpose [1]. poly (methyl methacrylate) properties are modified when reinforced by adding many particles or fibers, this is approach the scientist to study the effected of reinforced materials on the mechanical and physical properties for the composite material. the glass transition temperature (tg) of commercial poly methyl mailto:qah84@yahoo.com al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 418 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. methacrylate (pmma) it ranges from (65 to 165 c) [2 and 3]. the literature surveys include some researches, which are accomplished in this field, it’s: q.a. hamad, [4] studied the effect of adding two various types of reinforcing powders, which inclusive: nano-alumina (nano-al2o3) and nanosilica (nano sio2), on some physical properties of composite prosthesis complete denture base materials. the result showed the values of (thermal conductivity and thermal diffusivity) properties raised with increasing the volume fraction of both (nano-al2o3 and nanosio2) powders in pmma complete denture base materials. s.i. salih et. al., [5] investigated the prorated study the properties of flexural and the strength impact for pmma prosthetic complete denture base reinforced by different particles. the result showed the flexural properties rise with increasing the volume fraction of the while, reduced the impact strength. the one recent study mentioned elsewhere, which involved the numerical study by the tensile properties analysis of the prosthetic dentures which prepared from the same of composite material maintained in the reference above. jawad, k. olewi et. al. [6] studied the effects of the particles size and volume fraction of silica sio2 ceramic particles on the mechanical characteristics of pmma polymer. the results showed that the maximum shear stress, bending modulus, tensile strength, elongation percentage and modulus elasticity of pmma composites are increased with increasing the addition of sio2 particles and with the increase in the volume fraction of sio2 particles. azlan et. al. [7] investigated the effects of adding the hydroxyapatite (ha) with different volume fraction (5%, 10%, 15%, 20%), on the toughness of fracture, flexural and thermal properties of heat cure pmma resin to form pmma/ha composites. the results showed the flexural modulus and thermal conductivity of pmma was increased by increasing the volume fraction of ha particles this is referred to the reinforcement influences of ha particles. for ayman e. et. al., [8] this study investigates the effect of adding the aluminum (al2o3) particles with different weight fraction (5%, 10%, 15%, and 20%), on the flexural strength and thermal diffusivity of heat-polymerized acrylic resin. it was found increased significantly the flexural strength and thermal diffusivity in attribution to the percentage weight of alumina (al2o3) particles. according to schajpal s. b. et. al. [9] this study investigates the effect of adding the (silver, copper and aluminum) powders to acrylic denture base resin in different volume fraction. they found when increased, all these types of metal fillers lead to increased compressive strength, but decrease in tensile strength, also the fillers increased thermal conductivity but did not proportionally as the filler concentration increased. al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 419 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 1. materials and methods the material which used in this study the duracryl plus heat-curing base resin, fabricated by spofa dental company used as a matrix in this research. rice husk and bamboo powders in two different particles sizes (25 & 75 µm) and four weight fraction (2, 4, 6 & 8 %) used as reinforcing materials in acrylic resin. figure (1) illustrates the methyl methacrylate powder and monomer and the rice husk, bamboo powders which used to manufacture composite specimens. the rice husk and bamboo were washed many time then treated with (naoh) to remove lignin, pectin, waxy substances, and natural oils covering the external surface of the material cell wall and dried for five days then grinding and milling by grinder to very small particles then sieving to separate the various particle size. figure (1): (a) the powder and monomer of methyl methacrylate (b) rice husk powder. (c) bamboo powder. (c) (b) (a) al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 420 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table (1): some properties of pmma [10]. the resin is mixed in the weight rate 2.25:1 (two and a half parts of powder, one part of liquid), the mould which is closed put inside curing instrument for around (30 min.) a temperature equal to around (70ºc) and pressure equal to around (2.5 bar) according to company instructions to perform the curing process and in order to accomplished polymerization process of acrylic specimens and to improve physical properties. and then raise the temperature for around (30 min) to the (100 ºc) and stay at this temperature for one hour. then the process of cooling the mould begins inside the curing device in order to remove the residual monomer. the powders are treated with solution of 5% sodium hydroxide at 25°c for one day, keeping a powderto-liquor ratio of 1:30 weight to volume and then washed the treated powders many times by using distilled water to eject overflow alkali sticking on their surface, then the distilled water which was neutralized (ph-7) a few drops of acetic acid put it in and washed with distilled water again, then the treated powders stayed for 5 days to dry at room temperature and finally kept in a hot air furnace at (50-60°c). the process of mixing between the monomer liquid (mma) with reinforcement particles (bamboo or rice husk) should be homogeneous and constantly. then added the powder to the mixture and mixed progressively. the samples of acrylic resin were de-molded to eject from the mould holes which has upper and lower surface very smooth, and to remove the stress which residual followed by heat treatment at 100°c for 2 h. 2. results and discussion 2.1. page thermal conductivity results figures (2 & 3) illustrate the effects of the thermal conductivity on weight fraction of (bamboo and rice husk) powders respectively at both particles size (25 µm and 75 µm) in pmma resin. the values of the thermal conductivity increased with rise of the weight fraction for both particles size of natural powders. this due to the fact of natural these powders which have high thermal conductivity value compared with the pmma matrix [11]. properties values coefficient of thermal expansion 81-162 (10-6(cº)^-1) thermal conductivity 0.37 m cal/s(cm2)(cº/cm)= (0.17-0.25)w/m.k) thermal diffusivity (0.123-0.125) (mm2/s) density (1.1.7-1.2) (gm/cm3) al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 421 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (2): thermal conductivity and weight fraction of bamboo powder at both particles sizes for pmma composite specimens. in addition, the presence of these particles is made to fill or diminish all spaces and voids which were inside the pmma matrix. finally, these reasons lead to facilitate the process of the heat transfer through composite specimens. so, the presence of the powders can considerably improve the thermal conductivity [2 and 3]. figure (3): thermal conductivity and weight fraction of rice husk powder at both particles sizes for pmma composite specimens. al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 422 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. thus, the thermal conductivity values increase from (0.46 w/m. k) for pmma to (1.22 w/m. k) for (pmma 8% ba) composite specimen at particle size (25 µm) and to (1.1 w/m. k) for (pmma 8% rh) composite specimen at particle size (25 µm). 2.2. thermal diffusivity results the figures (4 and 5) illustrates the dependence of the thermal diffusivity on weight fraction of (bamboo and rice husk) powders respectively at both particles size (25 µm and 75 µm) in pmma resin. it can be shows that the values of the thermal diffusivity increased with increasing of the weight fraction for both particles size of both powders. it can also be noticed that the thermal diffusivity of pmma composite that content bamboo powder or rice husk powder at particles size (25 µm) is higher than the thermal diffusivity at particles size (75 µm). thus, the thermal diffusivity value increased from (0.3 mm2/s) for pmma to (1.04 mm2/s) for (pmma 8% ba) composite specimen at particles size (25 µm) and to (0.953 mm2/s) for (pmma 8% rh) composite specimen at particles size (25 µm). figure (4): the relationship between thermal diffusivity and weight fraction of bamboo powder at both particles sizes for pmma composite specimens. al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 423 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (5): the relationship between thermal diffusivity and weight fraction of at rice husk both particles sizes for pmma composite specimens. also, the addition of both types of powders at both particles size leads to a significant increase in the value of the thermal diffusivity in comparison with the pure pmma. also the highest value of thermal diffusivity was obtained in composite material when adding bamboo powder at particles size (25 µm). 3. differential scanning calorimetric traces dsc test the most important thermal properties in this test are glass transition temperature (tg). the values of glass transition temperature, melting temperature and crystallization temperature for pmma material specimens before and after adding both types of natural powders (bamboo or rice husk powders) for both particles size at weight fraction (8 %) are listed in table (2). it was observed from the table (1) that the pmma composites varies for many reasons including, changes in nature and type of reinforcing material in composite and the particle size of natural powder in composites. however, the dsc scans of pmma composite specimens with presence both types of natural powders (bamboo and rice husk) at both particle size in the pmma matrix, leads to the increases of (tg), due to the good interfacial reaction between reinforcing materials and pmma polymer in composites, that produced strong bonding between reinforcing materials and pmma polymer composite. also observed the nature of natural powders (bamboo and rice husk), which did to restricted the pmma chain mobility, and acted as an agent to increase the cross-linking density between themselves and pmma chains. finally, that leads to increases in the molten state viscosity and rise the glass transition temperature for all composite specimens, these results are consistent with previous results as reported in the sources [14 and 15]. the maximum value of glass transition temperature was obtained in the composite specimen (pmma 8 % ba) at particle size (25 µm). it can be also noticed that the composite specimen (pmma-8 % ba) having a higher value of glass transition temperature than composite specimen (pmma-8 % rh) at both particle size. furthermore, the study of dsc thermal analysis indicated that there is no significant change in the heat flow behavior between the pure pmma and pmma composites materials, as well as it indicates to effective compatibility between constituents of pmma composite. al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 424 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. in addition, it can be noticed from table (2), there is not any significant can be mentioned about the effect of adding bamboo powder and rice husk powder on the other properties values (melting temperature and crystallization temperature) for pmma pure and composite pmma specimens table (2): the important characterization of dsc curves for pmma pure and composite pmma specimens for denture base materials. conclusions: 1. the thermo-physical properties of (pmmaba) composite and (pmmarh) composite increase with the rise of the weight fraction of (ba and rh) powders. 2. in dsc test, the value of glass transition temperature (tg) increases for all pmma composites reinforced by either bamboo powder or rice husk powder with increasing the weight fraction and decrease the particle size for both types of these powders when compared with pure pmma. 3. the highest values of (tg) was obtained for (pmma8% ba) composite specimens at particle size (25 µm). references 1. k.j. anusavice, “phillips’ science of dental materials”, w. b. saunders co., st. louis., 11th ed., 145-737, (2008). 2. stanley r. sandler, wolf karo, jo-anne bonesteel and eli m. pearce. "polymer synthesis and characterizationa laboratory manual", 1st ed, academic press, new york, (1998).. 3. belhaneche-bensemra n., bedda a., "analysis of structure properties relationship of pvc-pmma blends", ann. chim., vol.26, no.3, pp.79-90, (2001). 4. q.a. hamad, “study the effect of nano ceramic particles on some physical properties of acrylic resins”, engineering and technology journal vol.35, part a, no.2, (2017) 5. sihama i. salih, jawad k. oleiwi and qahtan adnan hamad, "numerically and theoretically studying of the upper composite complete prosthetic denture", eng. & tech. journal, vol.33, part (a), no.5, pp.10231037, (2015). 6. jawad, k. oleiwi, farhad, m. othman and israa, f. qhaze, "a study of mechanical properties of poly methyl methacrylate polymer reinforced by silica particles (sio2)", engineering and technology journal, vol.31, no.15, pp. 2925-2941, part a, (2013). 7. a. azlan et. al., “mechanical and thermal properties of hydroxyapatite filled by poly (methyl methacrylate) composites,” proceedings of the polymer processing society 24th annual meeting, university of sains, malaysia, (2008). specimen tg tc tm pure pmma 121.5 356.7 412.152 pmma 8 % ba at (75 µm) 129.1 394.7 540.98 pmma 8 % ba at (25 µm) 131.6 383.8 431.369 pmma 8 % rh at (75 µm) 128.6 325 421.674 pmma 8 % rh at (25 µm) 129.2 365.7 453.042 al-qadisiyah journal for engineering sciences vol.11, no.4 issn: 1998-4456 page 425 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 8. ayman e. ellakwa, mohamed a. morsy, and ali m. el-sheikh, "effect of aluminum oxide addition on the flexural strength and thermal diffusivity of heat-polymerized acrylic resin", journal of prosthodontics, vol.17, pp.439-444, (2008). 9. schajpal s. b. and sood v. k., "effect of metal fillers on some physical properties of acrylic resins", jour. pros. dent.; vol. (61), pp.746-751, (1989). 10. o’brien w j., ”dental materials and their selection”, 3rd ed. chicago: quintessence int, pp.216-20, (2002). 11. jawad k. oleiwi, sihama i. salih and hwazen s. fadhil, "water absorption and thermal properties of pmma reinforced by natural fibers for denture applications", international journal of mechanical and production engineering research and development, vol.8, issue 3, jun, pp.1105-1116, (2018). 12. fu, shao‐yun, and yiu‐wing mai., "thermal conductivity of misaligned short‐fiber‐reinforced polymer composites", journal of applied polymer science, vol.88, no.6, pp.1497-1505, (2003). 13. p. mummery, w. n. dos santos, and a. wallwork, "thermal diffusivity of polymers by the laser flash technique", polymer testing, vol.24, (2005). 14. carola esposito corcione and mariaenrica frigione, "characterization of nanocomposites by thermal analysis materials", vol.5, pp.2960-2980, (2012). 15. chow wen shyang, h. k. tay, a. azlan and z. a. mohd ishak, "mechanical and thermal properties of hydroxyapatite filled poly (methyl methacrylate) composites", proceedings of the polymer processing society 24th annual meeting, pps, university of sains malaysia, june, (2008). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 629 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. doi: 10.30772/qjes.v10i4.513 abstract: automatic control of automotive engines provides benefits in the engines performance like emission reduction and fuel economy. the drop in idle speed problem can be seen as the disturbance rejection problem in the main engine speed. in this paper, a pid-like fuzzy logic control (pidfc) with minimum structure for the four strokes, four cylinders, gasoline engine is designed and simulated to maintain the engine speed at nominal value in idle speed mode. the speed performance must satisfy minimize fuel consumption, and as a result reduces the fuel emissions. a spiking neural network (snn) trained by particle swarm optimization (pso) algorithm is proposed to online-adapt the inputs and output gains of the pid fuzzy controller in order to achieve the required speed performance. a mean value engine model (mvem) is used to simulate nonlinear model of engine. .results of simulation for this controller showed good improvements over the pidfc in the idle speed response. .the peak overshoot is reduced about (70 %), the undershoot is reduced about (50 %), the settling time is. .reduced about (83%) and the fuel consumed is reduced about (53%). keywords: mean value engine model, fuzzy logic control and spiking neural network. ............................................................................. nomenclatures symbol description unit symbol description unit a area m2 . n angular acceleration rad/s2 c1 and c2 acceleration coefficients of pso method n population size cd discharge coefficient pa ambient pressure n/m2 dth throttle valve diameter m pc critical pressure n/m2 spiking neural networks based pid like flc design for an idle speed control of an automotive engine asst. prof. dr. mohammed y. hassan, university of technology, control and systems department, baghdad, iraq. e-mail: 60003@uotechnology.edu.iq muslim abdulameer alghazali, university of technology, control and systems department, baghdad, iraq. e-mail: muslim_control@yahoo.com received on 23 october 2017 accepted on 27 december 2017 published on 15 march 2018 mailto:60003@uotechnology.edu.iq mailto:muslim_control@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 630 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. introduction most of the automotive machines use in everyday life equipped with gasoline port fuel injection (pfi) engines. ordinarily these engines are of spark ignited (si), four strokes and otto cycle based conversion of chemical energy from fuel to mechanical energy [1]. these engines run in different operating conditions during their life cycle such as cold start, idling, cruising…etc. these operating conditions are different fro each other in objectives and performance. at idle operating mode that characterizes by low speed of engine ordinarily between (750-1400) revolution per minute (rpm) [1] valve of the throttle is closed. idle speed control is represented one of difficult and public problem in engine of automotive, because of nonlinearity, complexity and time delay presented by the system. so, a controller is compensated for error in speed is needed. the controllers have to supply best dk delay of specific synapse m.s pex exhaust gas pressure n/m2 e error pm intake manifold pressure n/m2 i neuron sequence in hidden layer qhv heating value of fuel j/kg j neuron sequence in output layer r1 and r2 random numbers vm intake manifold volume m3 rmax and rmin minimum and maximum value in the pattern j moment of inertia kg. m2 r constant of gas j/kg.k k synapse sequence in the connection rp pressure ratio m3 cma . mass flow rate of air into the cylinders kg vc clearance volume m3 mf mass of fuel for one cycle kg/s vd displacement volume n.m . mf f mass flow rate of air past the throttle kg/s ta ambient temperature k . mf mass flow rate of fuel that enters the cylinder kg/s tm intake manifold temperature k . mat mass flow rate of the fuel film kg/s it t intake to torque production delay s . mf v mass flow rate of the fuel vapor kg/s st t spark to torque production delay s . mf i mass flow rate of the injected fuel kg/s x fuel film fraction n rotational speed of engine rp m z number of cylinders al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 631 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. results with improved economic in fuel and emissions reduction. many of the control methodologies for the problem of idle speed suggested during the past decades. different papers discussed idle speed control techniques with the corresponding control oriented model used were published. this includes control techniques based on different modern control alternatives such as linear quadratic (lq), fuzzy logic techniques and neural network. panse, [1] presented a dynamic-oriented control mean value engine model of a pfi engine. the controller is developed by pid to idle mode which used throttle valve to regulate the speed. the development of successful controller maintained the stable state of the idle speed in the simulation. santes et al., [2] presented the isc as one of problems of calculating a greater group set for a modeling of crossbred system for si engine. the problem is represented by computing a maximum set of safe for a crossbred system modeling of an si engine. an algorithm in the discrete time domain was proposed for the determination of the maximal safe set without assuming synchronization between sampling time and switching time for idle control. simulation results showed increasing efficiency of the proposed approach. gibson et al., [3] presented lead reparations analysis, feed-forward and design techniques to monitor disorder for isc system with minimum reserve spark level. a reduction of 30 per cent in the maximum reduction of the speed of engine was obtained compared with an isc with no observer compensation disorder lead. the disturbance rejection response is compared with response from conventional idle speed control with high levels of spark reverse. a cylinder by cylinder non-linear engine model and idle speed control simulation were used to prove the results of linear simulation. ghaffari et al. [4] presented a modeling of a spark ignition engine and demonstrated capabilities of simulink to full engine model. a pid adapting method which used an adaptive flc for modeling the relation between gains of the controller and the response of target output, with the specifications set response by required percentage settling time and overshoot, was designed. the adaptive flc used to tune online the gains of pid for different response of specifications. the results showed that better performances achieved with the full controller. syed et al. [5], presented the process in field of automotive to implement the rule-based fuzzy gain scheduling pi controller to control the engine power required and behavior of speed in the power-split hybrid electric vehicles (hev). the improvements include elimination of the overshoots as well as approximate by 50% faster response and settling times in comparison with the conventional linear pi control approach. wong et al. [6] in 2009 presented a non-linear model algorithm of predictive control for afr organization based the online neural networks. the implementation of the control in the real car as a check. the actual result of the test showed that the engine air ratio can be regulated to the stoichiometric value (1.0). liu and zhou, [7] in 2010 described a simulation based fuzzy neural network (fnn). the engine model used here is a mvem that incorporates nonlinearities and time delays exhibited by the system. this model consisted of three important subsystems that represented the behaviors of the fuel, the acceleration of the crankshaft and the intake manifold dynamics. they found that the error of air fuel ratio (afr) is large under transient conditions, when throttle degree is changed. when using a fnn controller, the afr errors can be controlled to a tight range. the system has smaller overshoot lower adjust the time. angel et al. [9] presented a flc to maintain stoichiometric afr in the engine for achieving a required ratio for emissions reduction, energetic efficiency improvement and power generation, with a reduction in the temperatures operating of an engine. the control is accomplished with precision devices led by the electronic control unit (ecu). it is essentially a logical device that is responsible for maintaining a stoichiometric air-fuel ratio. xiaocheng et al. [10] analyzed a pid control, flc and pid like flc are designed, by applied these three controllers to isc of the automotive gas engines. they found that the pid like flc is of high progress during contrastive analyses in control effect of the three controllers in the process of cooling high idle start, switching high to low idle and low to high idle. shamekhi et al. [11] proposed a mvem and anns by including them in mean value model. they presented a real-time model with high definition and dedication for the engines of spark ignition, as fully as possible. by incorporating the neural networks into the mathematical approximation relationships of the engine, they named the model as neuro-mvem, which is able to accurately predict the engine (transient and steady states) outputs such as torque producing, emission and speed engine in real time. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 632 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. as mentioned above, no papers have been reviewed had developed a model for the entire engine or for its behavior of transient. the above-mentioned work is almost limited to predict some of the static state characteristics of the combustion subsystem. in this paper, combination of fuzzy logic control and spiking neural networks to control the mean value engine model is presented, the snn uses to adapt the inputs and output gains of pidfc and uses the pso algorithm to train the weights of snn. a complete engine model which is able to closely indicating dynamic of engine and transient performances and emissions pollutant is built. 1. mean value engine model of si engine the automotive engine is modeled using a class of models called mean value engine models (mvems). 1.1. engine modeling the model is including fuel, air and rotational dynamics also process delay attendant in the engine. in si engine, it is useful to divide it in separate subsystems [12]. the subsystems are: 1intake air dynamics. 2fuel dynamics. 3crankshaft dynamics. 1intake air path dynamics: it is divided in to : a-throttle body: the mass flow of air in cylinder, and thus power of output engine is controlled by the throttle valve. it is opened depending on the position of pedal. the air mass flow through the throttle valve can be modeled as a gas flow through an orifice. this is calculated as a function of two variables: the area available for the flow (a(t)) and the pressure ratio across the throttle section[12]: . bintake manifold dynamics: it can be represented by a first order differential equation, the changing rate of manifold pressure is proportionate to the difference between mass of air flow into the manifold and the pumped mass of air into intake port as given below [13]: )( . )( . tma vm rtm tpm  where . )( . )( . )( tmactmattma  cair induced in cylinders: the mass flow rate of the mixtures of exhaust gases and air is calculated using this concept where its mathematical expression is as follow [13]: vvdz tn rtm tpm tmac    )( 4 )( )( . ))(())(( tpm pm tn nv   where: ))(( 2 )( 1 ))(( tntntn n    )())(( )( )( . tatrp rta tpa cdtmat  (1) (2) (3) (6) (5) (4) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 633 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved.   1 ) )( ( tpm pex vd vc vd vdvc pm    2fuel path dynamics fuel dynamic is important for the in cylinders afr calculation. in general, it is difficult to accurate the fuel dynamics model, because the model parameters depend on the characteristics of fuel and engine temperature during its operation [15]. the injector of fuel is injected fuel as pulses when the valve of intake is close [1]. part of the injected fuel hits the wall of manifold and forms thin film on it. this fuel film on the intake port evaporates constantly, therefore, the net fuel flow rate entering the cylinders consists of no impinging part of the fuel injection and the fuel evaporated from the intake port walls, dynamics of fuel may be represented by the equations [15]: )( 1 )( . )( . tmff f tfimxtffm   the afr is to remain at (14.673) [7]. the injections of fuel . mf i are adjusted for progress of the charge air. the charged of air to the cylinders is divided by afr to supply the feed-forward command of fuel flow. 3crankshaft dynamics the variable crankshaft of important is the speed of revolution express in rpm or rad per second (rad/sec) that depended on the production torque by cylinders through stroke expansion. three models should dissect distinctly in the dynamic model of crankshaft. these are: torque production, delays of process and dynamics rotation.al of the engine. atorque production model it is depended in a non-linear type on the air mass loaded to the cylinders; afr is taken during the timing of spark, earlier intake stroke and mass of remaining gases [9]. the model described here is a mean value model uses the notation of mean effective pressure (mep), since it depended on the same variables that effect the torque of engine, as well as, the torque function is just an expansion of the break mean effective pressure (bmep) function. it's expression as follows [9]: )( 4 )(/ . hv q)( )( tnvdtfa tmac t fe mep      and the bmep is expressed as follows [1]: ))(),(( 4 hv q )()/( ))(())(),(( )( tpmtn vdtnfa tntntpmmac tbmep          and (7) )( . )1()( . tfimxtfvm  )( 1 )( . )( . tmff f tfvmtfm   (8) (9) (10) (11) (12) (13) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 634 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. vd tb bmep 4   so    4 ))(),(( )()(/ ))(())((),(( vd tpmtn hv q tntfa tntpmtnmac tb     bprocess delays model it is depending on the speed of engine. to add the discrete behavior of the engine to this model, two delays are included in the model, intake and spark to delay the torque production [14]. by incorporation the delays in equation (14) give: (15)    4 ))(),(( )()(/ ))(()( vd tpmtn hv q tntfa tn it ttmac tb     crotational dynamics model it is acquired by applying second law of newton for rotational motion: [1] tnet is calculated from the difference between the production torque by the cylinders and the sum of all the load torques placed on the engine. the load torque (td) value usually varies around (30n.m) for low and medium range of engine speeds [12]. the fuel consumption (f.c) is the consumed fuel by the engine during the period of operation. in this paper this can be calculated by summing the injected fuel (mfi) at each sample time [4]. 2.2. parameters identification in this paper, the simulation is done for a mitsubishi motor of engine model no.4g64 .the 4g64 engine is a single overhead camshaft, 4 cylinders, 4 valves per cylinder gasoline powered, four strokes, pfi and si engine prototype with idle speed equals to 955 rpm. all the physical parameters used in the model are listed in table (1) . the engine geometry parameters needed in the model is listed in table (2), the coefficients of the curve fitting equations used in the model are listed in table (3). 2.3. simulation results the open loop dynamics for the nonlinear engine model has been obtained for step change in the throttle angle without and with applying variable value of the load torque (td) as explained below: (14) . njtnet  (16) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 635 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. a) step in the throttle angle with no load torque: a step change in the throttle angle is applied to the model within a range of 9.1558 degree (0.159 rad) to 9.1959 degree (0.161 rad) at 10 seconds [1]. the engine rotational speed is shown in figure (1). b) applied about load torque: the load of engine during idling is of variable nature and this could be the source of sudden rise or drop in speed of engine [1]. the nonlinear model is loaded with variable values of load torque. the load torque is applied first as a step change form to represent the loads that affect suddenly. then a trapezoidal signal used to represent the loads is increased gradually [16]. finally a sine wave signal is also used to represent the load torque .the loads were applied with the same step change in the throttle angle that was used before. the open loop responses are shown in figure (2). figure1: (a) open loop speed response. (b) air fuel ratio. table 1: physical constants[1] . parameter value α0 0.1379 rad dth 86.5*10-3 m aleak *10-6 m25.3 vm 2.351*10-3 m3 vd 2.77*10-3 m3 vc 0.277*10 -3 m3 j 0.3 kg.m2 table 3: equations coefficients parameter value r 287 j/kg.k ta 298 k pa 105 n/m2  1.35 tm 340 k cd 0.7 pex 1.08*10 5 n/m2 parameter value  0.45 3.42*10-3 sec 2  -7.7*10-6 sec2  0.16 j/kg 1  2.21*10-3   15.6 n.m 1  0.175*10-3 1  table 2: engine parameter [1] . 0 5 10 15 20 25 30 -200 0 200 400 600 800 1000 0 5 10 15 20 25 30 14 15 16 17 18 19 20 21 e n g in e s p e e d ( r p m ) time (sec) time (sec) a) b) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 636 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 2: open loop dynamics of the mvem with applying different values of load torque. (a) speed response. (b) load torque. 2. idle speed controller design the design of intelligent controller for automotive engine is considered. the isc is formalized as a control problem, where the stalling of engine must be prevented despite of load varying and acting. so, the model of engine with the controller designed had to obtain the idle rotational speed with minimum steady state error, minimum undershoot, minimum overshoot and reach as fast as possible to the target rotational speed. one successful control technique is fuzzy control which originates from the human experiences. the objective of the fuzzy logic control (flc) systems is to control complex process by experience of human being." the idle speed controller designed in paper is of pid-like flc to recompense for the descend in the engine rotation speed, it uses the throttle angle only. 2.1. fuzzy logic control (flc) design it is a pid like fuzzy controller pidfc is developed. this controller uses the discrete from with minimum structure form of the conventional pid controller equation as follows:  )()()( ke t ki kekdtkkpeu where e(k) is the error signal and the index (k) represents the present sampling instant and assumed that the sampling time equals to 1 sec. "it is clear from the equation that the controller has three inputs. if seven fuzzy sets are used for each input, then a (7*7*7=343) rules will be needed for the controller. also, each rule will have three conditions in its antecedent part, which is very difficult to design such controller and needs too much work [17]. to avoid such problems, the pidfc is constructed as a parallel structure of pd like fuzzy controller pdfc and pi like fuzzy controller pifc. as a result, the equation of the pidfc will be: pidfc=( pdfc+pifc )ko where )()( kekdkkpepdfc  (17) (18) (19) 0 10 20 30 40 50 60 70 80 0 100 200 300 400 500 600 700 800 900 1000 0 10 20 30 40 50 60 70 80 0 5 10 15 20 25 30 35 e n g in e s p e e d ( r p m ) time (sec) time (sec) l o a d t o rq u e ( n .m ) a) b) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 637 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. and  pdfcpifc each controller will need two inputs only. with seven fuzzy sets for each input, this result in 49 rules which will be needed. so, the pidfc will need (49) rules only. moreover, the pidfc is designed using mamdani type [13]. it has two inputs e(k) and δe(k) and one output. the inputs are defined as follows: )()()( kykrke  )1()()(  kekeke moreover, all the membership functions of the flc inputs and output are defined on the common normalized domain [-1, 1],and the triangular and trapezoidal membership are used. the rule base for computing the output (u(k) (δu(k)) )is listed in table (4) . the selection of rules shown is based on the knowledge of the behavior of the error equation. table 4: rule base of the pidfc. the scaling factors of flc are tuned manually. the error allowed using this scaling factors, a set of pidfc gains are (kp=0.018, ko=0.15 and kd=0.008). 2.2. pidfc simulation results………………………………………………………… the closed loop system with pidfc controller is simulated by applying variable values of the load torque and disturbance discussed below: a) applying the load torque: a variable value of a load torque is applied to the closed loop system in order to check the ability of controller to the reference tracking of idle speed (equals to 955 rpm) in the presence of load torque. the constant load torque of (30 n.m) is applied after 15 seconds to ensure enough time to examine the speed response and it is removed in the 25th second. figure (3) shows the engine speed response obtained using pidfc with applying constant load torque and without disturbance. the overshoot equals to 290 rpm, undershoot equals to 158 rpm, settling time equals to 1.5 sec and fuel consumption equals to 0.0017 kg. b) applying load torque with disturbance: controller robustness should be achieved with respect to parameter uncertainties and unmolded dynamics, represented by engine load torque and disturbance [4]. so, a random value of disturbance ranging between ±10% of the load torque was applied to test the controller ability to overcome noisy disturbance. figure (4) shows the engine speed response obtained using pidfc with applying constant load torque and with disturbance. the overshoot equals to 294 rpm, nb nm ns z ps pm pb nb pb pb pb pb pm ps z nm pb pb pb pm ps z ns ns pb pb pm ps z ns nm z pb pm ps z ns nm nb ps pm ps z ns nm nb nb pm ps z ns nm nb nb nb pb z ns nm nb nb nb nb (21) (22) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 638 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. undershoot equals to 164 rpm, settling time equals to 1.5 sec and fuel consumption equals to 0.00187kg. figure 3. simulation results of the closed loop system with pidfc (a): engine speed with constant load torque (b): control signal (throttle angle) figure 3: simulation results of the closed loop system with pidfc. (a) engine speed with constant load torque. (b) control signal (throttle angle). figure 4. simulation results of the closed loop system with pidfc (a): engine speed with constant load torque (b): load torque figure 4: simulation results of the closed loop system with pidfc. (a) engine speed with constant load torque. (b) load torque. . 4. spiking neural network (snn) in this work, a snn is used to on-line adapt the inputs and output gains (scaling factors) of the flc. the snn weights are trained using pso algorithm to reach the desired idle speed of the engine with better performances. as a result, fuel emissions are reduced and fuel economy is obtained. 0 5 10 15 20 25 30 0 200 400 600 800 1000 1200 1400 0 5 10 15 20 25 30 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 e n g in e s p e e d ( r p m ) time (sec) time (sec) b) t h ro tt le a n g le (r a d ) 0 5 10 15 20 25 30 0 200 400 600 800 1000 1200 1400 0 5 10 15 20 25 30 -5 0 5 10 15 20 25 30 35 e n g in e s p e e d ( r p m ) time (sec) time (sec) a) b) l o a d t o rq u e ( n .m ) a) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 639 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the structure of the proposed snn is shown in figure (5) . as can be seen from this figure, the snn consists of one node in the input layer which receives the error in engine speed in the output layer of snn, three nodes are used to represent the gains of the controller (kp , kd and ko). the simulation of closed loop is shown in figure (6) . figure 5: proposed structure of the snn. figure 6: simulink of closed loop system of the engine model with snns based pidfc. 4.1. snn training using pso algorithm the particle swarm is used as an optimization algorithm to find the best weights of snns to obtain accurate speed engine response with minimum undershoot, minimum overshoot and minimum settling time. this minimization gives closer matching between the desired and the actual idle speed. the pso is initialized randomly. however, the convergence speed is sensitivity to the initialization. the design of control is used the optimal solution supplied by the snns based pso. kp ko kd e al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 640 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. as the fitness function which uses to evaluate the fitness of each particle during tuning process with pso, the root mean squared error (rmse) and the overshoot in speed response are included in the fitness function to reach the required speed specifications. the fitness function is selected as: f=rmse*0.09+ (overshoot*0.01) (23) where rmse = 1 𝑀 ∑ √𝑒2 and m : is the number of samples the general specifications of snn are presented in the table (5) . the number of units in input /output are 1and 3, respectively. the other specifications of the pso are the number of birds is 50, the steps of birds is 30, the learning factors (c1,c2) are both equals to 4 and the number of weights to snn equals to 60. by training the snn using idle speed response without and with varying load torque, disturbance and changing the ambient temperature to reach the minimum rmse, it is found that the best number of hidden nodes equals to (5) and the best weights for hidden and output layer equals to 60 weights as listed in appendix a. 4.2. simulation results of snn based pidfc (snn-pidfc) a snn-pidfc has the ability to deal with this nonlinearity and to achieve speed tracking performance with minimum speed error. the input of the spiking is the error which is converted to times of spike. the output signals of snn are also spike characterized with time of spike. this time of spike is converted to real numbers that enter to the model input as scaling factors of the fuzzy controller. in order to test the behavior of the proposed controller, the training algorithms give weights that are used in this snn as a feed-forward network to generate the required gains during the synthesis of the input signals of the snn control system. the closed loop system with snn-pidfc controller is simulated with applying variable values of the load torque without and with disturbance as discussed below: a) applying the load torque: figure (7) shows the engine speed response obtained using fuzzy controller by applying constant load torque and without disturbance. it can be show from the results that the overshoot equals to 87 rpm, undershoot equals to 7 rpm, settling time equals to 0.245 sec and fuel consumption equals to 0.000785 kg. b) applying load torque with disturbance: figure (8) shows the engine speed response obtained using the controller with applying constant load torque and with disturbance. it can be show from the results that the overshoot equals to 87 rpm, undershoot equals to 83 rpm, settling time equals to 0.245 sec and fuel consumption equals to 0.000809 kg. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 641 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7: (a) simulation results of the closed loop system with snns based pidfc with applying constant load torque. , (b) control signal (throttle angle). figure 8: (a) simulation results with snns based pidfc to engine speed with applying constant load torque with disturbance. , (b) control signal (throttle angle). conclusions to achieve an improvement on the speed response, a snn based pidfc (snn-pidfc) was designed and good improvement has been obtained. the snn was used to adapt the inputs and output gains of pidfc. simulation results with using snn-pidfc showed that the peak overshoot is reduced to about (70%) as compared with using pidfc only for the same value of the load torque, the undershoot is reduced to about (50%) as compared with using pidfc. the settling time is 0 5 10 15 20 25 30 0 200 400 600 800 1000 1200 0 5 10 15 20 25 30 -0.5 0 0.5 1 1.5 2 2.5 3 e n g in e s p e e d ( r p m ) time (sec) time (sec) a) ) b) 0 5 10 15 20 25 30 0 200 400 600 800 1000 1200 0 5 10 15 20 25 30 -0.5 0 0.5 1 1.5 2 2.5 3 e n g in e s p e e d ( r p m ) time (sec) time (sec) t h ro tt le a n g le ( ra d ) t h ro tt le a n g le ( ra d ) a) ) b) al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 642 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. reduced by (83 %) as compared with using pidfc. fuel consumed is reduced by (53 %) as compared with using pidfc. finally, it can be concluded that the snn-pidfc can be used to control the idle speed mode in the four stroke, four cylinders pfi, si engines by controlling the throttle valve and, thereby, the mass of air loaded to the engine. fuel particles are reduced, thus the engine consumes less fuel. this also reduces air pollution and preserve the environment of earth, especially, the fuel will decrease in nature which increases it's price. references 1. p. a. panse , "dynamic modeling and control of port fuel injection engines", master thesis, indian institute of technology, 2005, india. 2. e. d. santis, m. d. d. benedetto, and g. girasole , "digital idle speed control of automotive engines using hybrid models", ifac, 2005. 3. a. gibson, i. kolmanovsky, and d. hrovat , "application of disturbance observer to automotive engine idle speed control for fuel economy improvement", proceedings of the ieee american control conference, 14-16 june 2006, minnesota, usa. 4. a ghaffari, ah shamekhi, a saki and e kamrani. , " adaptive fuzzy control for air-fuel ratio of automobile spark ignition engine" world academy of science, engineering and technology, vol. 48, pp. 284-292, 2008. 5. u. syed and l. kuang , "fuzzy gain-scheduling proportional–integral control for improving engine power and speed behavior in a hybrid electric vehicle" , ieee transactions on vehicular technology, vol. 58, no. 1, pp 69-83, january 2009 6. p.k. wong and c. m. vong , "predictive air-ratio controller for automotive engines based on online neural network: design and experimental evaluation", 9th ieee/acis international conference on computer and information science, pp. 275-291, 2010. 7. l. qiang and z. cai , "a fuzzy neural network and application to air-fuel ratio control under gasoline engine transient condition", ieee international conference on intelligent system design and engineering application, pp. 24-26, 2010. 8. h. ming and g. yang , “a genetic-fuzzy system for modeling of selected processes in diesel engine fuelled by biofuels,” in recent developments and prospects, ser. biofuel production. intech, vol. 22, pp. 561 – 576, 2011. 9. m. a. m. morelos, m. j. anzurez , "fuzzy control strategy for stoichiometric air-fuel mixture in automotive systems", proceeding in world automation congress, 2012. 10. g. xiaocheng, x. zhongming, l.jingbo2 and z. bowen , " fuzzy pid model -based study on idle control of gas engine", bentham open, vol.8, pp.660-666, 2014. 11. a. mohammad and a. h. shamekhi , " expert systems with applications", published by elsevier ltd, vol. 27,pp. 1-27, 2015. 12. f. pettersson , "simulation of a turbo charged spark ignited engine" linkoping university, may 2000, sweden. 13. s. boveie, p. cerf, and j. m. l. quellec , "fuzzy sliding mode control application to idle speed control", proceeding of the 3rd ieee conference on fuzzy systems, vol. 2, pp. 974-977, 26-29 june 1994, orlando. 14. r. kruse, j. gebhardt , and f. klawonn , "a fuzzy controller for idle speed regulation", proceedings of the acm symposium on applied computing, 1994, u.s.a 15. r. g. ford , "robust automotive idle speed control in a novel framework" ph.d. dissertation, university of cambridge, september 2008. 16. d. mieczysław and c. jacek , " modeling and verification failures of a combustion engine injection system " , teka kom. mot. energ. roln., 2011 17. m. m. polonskii , "complex system simulation using matlab/simulink", technology interface electronic journal supported by ball state university, vol. 4, no.1, winter 2000. article al-qadisiyah journal for engineering sciences 12 (2019) 184–192 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7814136944. e-mail address: mohamed.aldawody@qu.edu.iq ( mohamed al-dawody) https://doi.org/10.30772/qjes.v12h3.616 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. computational combustion and emission analysis of biodiesel in a variable compression ratio engine mohamed al-dawody a b * and s.k. bhatti b afaculty of engineering – university of al-qadisiyah-iraq bdepartment of mechanical engineering college of engineering (a) /andhra university -india a r t i c l e i n f o article history: received 15 september 2019 received in revised form 05 october 2019 accepted 10 october 2019 keywords: soybean biodiesel performance emissions cfd analysis a b s t r a c t the aim of the present study is to analyse the combustion characteristics, performance and emission parameters of a variable compression ratio (vcr) diesel engine experimentally and numerically using soybean methyl ester (sme) biodiesel. initially the engine is fed with diesel to capture the basic data, and then sme was tested as 20 % blend (b20), as 40% blend (b40) and as pure bio-fuel (b100). the experimental investigations are followed by a computational combustion and emissions analysis of diesel engine which is done by using the cfd software (ansys fluent 13). the combustion, performance and emissions parameters are evaluated by operating the engine at four different compression ratios of 15, 16, 17.5 and 19 and varying the load from 0 kw to 4.4 kw with 1.1 kw step. it is observed that peak pressure is closer to tdc when sme blends is increased. sme blend has earlier combustion start because of the advancement in the injection timing, shorter delay time. increasing mixing ratio of biodiesel is found to decrease bte slightly and increases the bsfc. remarkable decrease in uhc and co emissions as the ratio of sme is increased due to the complete combustion of biodiesel with presence of more oxygen in the combustion chamber. the measured bsn for b20, b40, and b100 sme was less than that of diesel fuel by 20.44%, 35.78%, and 48.3% respectively. it is inferred from the combustion analysis that as the compression ratio increases from 15 to 19 a decrease in smoke intensity, uhc, and co, but it increases the emission of nox. both turbulent kinetic energy and turbulent dissipation rate were decreased as the percentage of sme increased by 10.84% and 2.01% respectively. the increase in compression ratio from 15 to 19 caused an increase in the peak pressure, density, combustion velocity, turbulence, peak temperature, nox and a decrease in soot emissions. it can be assessed that the b20 sme is best suited to implement it into diesel engine without any effects. it has been founded from the results that 19 compression ratio has shown good performance and low emissions as compared to other compression ratios. the results obtained from the experimental investigation have been compared with the results of cfd analysis and are found to be in good agreement with each other with just slight deviation. © 2019 university of al-qadisiyah. all rights reserved 1. introduction for more than a century, the reciprocating internal combustion (ic) engines have been a dependable workhorse in a wide variety of applications that require mechanical motive power. from its inception in the late 1800s till date, tremendous progress has been made in the performance, reliability and efficiency. it is a well-known fact that diesel engines have deep impact on the industrial economy, as they are used in heavy trucks, city transport buses, locomotives, electrical generators, farm equipments, underground mine equipments etc., because of their simple, robust construction coupled with high thermal efficiency and specific power output with high fuel economy. increasingly tough emissions regulations coupled with fast http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12h3.616 mohamed al-dawodya, s.k. bhattib /al-qadisiyah journal for engineering sciences 12 (2019) 184–192 185 depleting crude oil resources have caused a stimulation of interest in finding alternative fuels for petroleum-based fuels like diesel and gasoline. for instance, on-road heavy-duty diesel engines face a stiff challenge in meeting the future standards for both nox and pm emissions. however many researchers directed to search for alternative energy source [1-2]. all over the world, biodiesel is subjected to intensive research work. biodiesel was found as the best alternate fuel, technically and environmentally acceptable, economically competitive and easily available. it has received much attention in the past decade due to its ability to replace fossil fuels, which are likely to run out within a century. especially, the environmental issues concerned with the exhaust gases emission by the usage of fossil fuels also encourage the usage of biodiesel, which has proved to be ecofriendly far more than fossil fuels. it can be produced from various vegetable oils, waste cooking oils and animal fats via transesterification process together with methanol as well as koh as a catalyst. compared to original diesel fuel, it is reported that biodiesel has greater levels of cetane number, density, viscosity, but at the same time the calorific values of biofuel is 10 to 12 percent less than petroleum diesel [3]. the largest producers of soybeans are: united states, brazil, argentina, china and india [4]. the findings of many investigations have emphasized that while a promising reduction in the carbon emissions but at the same the emissions of nox is increased as compared with neat diesel [5-21]. although biofuel has a higher cetane number than diesel fuel but the bulk modulus in addition to viscosity have deep impact on the behavior of combustion of the fuel. the higher bulk modulus has been observed to contribute higher nox production than neat diesel. the compressibility difference could lead to advance the injection timing hence, a greater chance to form nox is expected [22,23]. the major reasons behind nox emission are the start of injection, the time of peak heat release and peak temperature [24]. same findings is reported by [25–28]. this research work is aimed to conduct experiments on a diesel engine powered by neat diesel and different volumetric blends of (sme). the experimental investigation is followed by a computational combustion and emissions analysis of diesel engine is done by using the cfd software ansys fluent 13 2. biodiesel properties the soybean biodiesel under test is supplied from intech energy systems pvt. ltd [29]. the production of soybean biofuel based on transesterification process. as seen in table 1, all the properties of the biodiesel prepared meet the specifications required by astm d 6751-02 and en14214. the schematic steps of biodiesel production is shown fig.1 figure 1 steps of sme biodiesel production table 1, diesel and sme biodiesel [29] property diesel b20% sme b40% sme sme chemical formula c13.77h23.44 c14.97h26.33o0..34 c16.07h28.94o0.68 c19h35o2 density (kg/m3) 830 841 852 876 viscosity (cst) 3.0 3.34 3.68 4.25 calorific value (mj/kg) 42.5 41.18 39.89 36.22 flash point (oc) 76 86.8 97.6 130 cetane number 48 48.69 49.37 51.3 3. experimental investigation the kirloskar taf-1, single cylinder, air cooled, variable compression ratio and direct injection diesel engine is used in this work. the technical specifications of the engine are given in table 2. the actual photos of the engine and its attachments are shown in figs.(2-3). table 3 shows accuracy of smoke meter and gas analyzer as well along with their range of operation. nomenclature b20 blend contains 20 % sme and 80 % diesel [c] soot concentration in the cylinder b40 blend contains 40 % sme and 60 % diesel cn fuel cetane number b100 blend contains 100 % sme co carbon monoxide bp brake power uhc unburned hydrocarbons bsfc brake specific fuel consumption nox oxides of nitrogen bsn bosch smoke number p cylinder pressure btdc before top dead center pm particulate matter 186 mohamed al-dawodya, s.k. bhattib/al-qadisiyah journal for engineering sciences 12 (2019) 184–192 table 2, specifications of engine table 3, the operating ranges and accuracies figure 2 the actual photo of the engine test figure 3 the computer system attached to the test rig 4. computation model analysis in the present work, a standard finite-volume cfd code, ansys fluent 13 which is frequently used in automotive engineering because of its superior meshing generation, preand postprocessing, as well as the availability of user supports has been used to simulate the combustion process of variable compression ratio diesel engine working on sme-diesel blends. ansys fluent 13 solves the three-dimensional navier-stokes equations for a diesel engine. a choice of standard k model is added to for describing turbulence effect. sub-models are added for, ignition, turbulence-chemistry interactions and pollutant formation prediction. 4.1. turbulence model the standard k model is a semi-empirical model based on model transport equations. in the derivation of the k- model, the assumption is that the flow is fully turbulent, and the effects of molecular viscosity are negligible (launder b. et al [30]). the turbulence kinetic energy, k and its rate of dissipation , are obtained from the following transport equations [31]:     kmbk jk t j i i sygg x k x ku x k t                                 (1)               s k cgcg k c xx u xt bk j t j i i                             2 231 (2) 4.2. combustion model seven combustion species are considered, fuel, n2, o2, co, h2o, h2 and co2. the time rate of change of the concentration of species i is given by (yashuhiro k. et al [32])   cii i yy dt dy / *  (3) (4) the variable f can be considered as a coefficient that explains the effect of turbulence on combustion (kong sc. et al [33])., hence f is zero , before combustion and equals one when combustion completes. the laminar timescale is derived from a one step kinetic reaction rate as [31]:      rteohca nnl /exp 5.1 2 75.0 22 1     (5) the turbulent time scale is based on the eddy breakup concept and modeled as;  / 2 kc mt  (6) cm2 model constant for mixing characteristics in the engine. the local mass fraction of each species yi, is predicted through the solution of a convection–diffusion equation for the mth species i.e., (7) engine make kirloskar taf-1 engine type. 4-stroke, diesel engine number of cylinder 1 bore × stroke 87.5×110 mm cylinder capacity 0.66 l compression ratio variable (15, 16, 17.5, 19) rated power 4.4 kw , 1500 rpm maximum torque 28 n.m ,1500 rpm orifice diameter 0.15 mm injection timing 20o btdc injection pressure 220 bar emission range accuracy co 0-10 % vol ± 0.2 % 2co 0-20 % vol ± 1 % uhc 0-20000 ppm ±10 ppm 2o 0-22 % vol ± 0.2 % nox 0-5000 ppm ±10 ppm opacity 0-100 % ± 1 % tlc f      iiii i srjy t y      mohamed al-dawodya, s.k. bhattib /al-qadisiyah journal for engineering sciences 12 (2019) 184–192 187 4.3. nox model in this work thermal and prompt models have been used [30]. the mechanisms of thermal and prompt nox, the no species transport equation is just required: (8) 4.3.1. thermal nox model the principal reactions governing the formation of thermal nox from molecular nitrogen are as follows: nonno  2 (9) nooon  2 (10) nohohn  (11) the no formation rate becomes [30];                                     ohkok nok oknk nokk nok dt nod ff r ff rr f 3,22, 1, 22,21, 2 2,1, 21, 1 1 .2 (12) 4.3.2. prompt nox model the major contribution suggested as the prompt nox source is from ch and ch2, is given by: nhcnnch  2 (13) nhhcnnch  22 (14) the prompt nox formation rate can be approximately equal to the overall prompt nox formation rate:        rtea pr aefuelnokf dt nod / 22 ..  (15) where f -correction factor which incorporates the effect of fuel type, i.e., number of carbon atoms, and air to fuel ratio which is given by; 32 2.12322.230819.075.4   nf (16)   16 /104.6  a pr prtk (17) 4.4. soot model the one-step model predicted by [32] is used in this analysis (18) soot r -net rate of soot generation, is the balance of soot formation formsoot r , and soot oxidation combsoot r , combsootformsootsoot rrr ,,  (19) the rate of soot formation is given by a simple empirical rate expression: rter fuelsformsoot epcr / ,    (20) 4.5. cfd model 4.5.1. model geometry and mesh the cfd analysis investigated for combustion and emissions of sme– diesel blends by replacing the percentage of sme blend. the blended fuel is injected at 220 bars. the inlet temperature of air is considered to be uniform at 300k. the combustion chamber was drawn using gambit. the three dimensional model is based on was a virtual combustion chamber prototype at the end of compression stage. the valves and injector positioning can be understood with the help of fig.4. based on the varying compression ratio, the clearance volume changes but as the bore diameter remains the same, the height of the chamber has to be modified and new models have to be created for the analysis purpose. the height of the combustion chamber at the end of compression stroke is given for each compression ratio in table 4. application of the boundary conditions and meshing the combustion chamber are done using icem cfd by using a tetrahedral element. the mesh size for the model was considered as unity (1) .the total numbers of elements equal to 1157543 see fig.5. the grid is refined in order to capture the boundary conditions specially in regions closer to nozzle. figure 4 positioning of nozzle and valves on cylinder head (dim. in mm) figure 5 computational model-grid mesh combustion chamber       nononono sydyy t      ..     sootsoot soot t sootsoot ryyy t                 .. 188 mohamed al-dawodya, s.k. bhattib/al-qadisiyah journal for engineering sciences 12 (2019) 184–192 table 4, height of the chamber at different compression ratio compression ratio clearance volume (mm3) height (mm) 15 47246.608 7.857 16 44096.834 7.333 17.5 40088.031 6.666 19 36747.361 6.111 5. results and discussion fig. 6 presents the pressure of cylinder verse crank angle for neat diesel and biodiesel. the cylinder pressure for biodiesel is lower than diesel by 2.98% due to the difference in the heating value for biodiesel. it is noted that the peak pressure for b100 sme is 78.246 bars at 6o crank angle which comes neat to tdc than ordinary diesel where the maximum pressure was 80.65 bars at 9o crank angle. fig. 7 shows the full load rate of heat release verse degree crank angle. the value of heat release rate is decreased when biodiesel blends increased. the message from this figure is that the biodiesel blend had an earlier start of combustion. the same observations are reported by [34-36]. figure 6 variation of cylinder pressure with crank angle figure 7 variation of heat release rate with crank angle bsfc results are presented in fig.8 for different engine loads. the bsfc decreased as the engine load increased. this is because, the rate of increasing power is greater than consumption of fuel. while bsfc was calculated as 0.537 kg/kw h with sme b20 at 1.1 kw load; it was found as 0.275 kg/kw h at 4.4 kw. the bsfc is increased with the increasing sme percentage due to the higher viscosity and density with lower heating value of biodiesel compared to diesel fuel. at full load, bsfc for sme b20, sme b40, and sme b100 increased by 4.24%, 8.71%, and 14.66% respectively. fig. 9 displays bte verse load. from the above discussion, it is concluded that bsfc is increased as the substitution of biodiesel is increased., bte depends on bsfc and heat quantity as well. in general bte is reduced as the blend ratio of sme is increased . the result of uhc emissions are illustrated in fig. 10 for different loads. typically, (sayin c. et al [37]). while uhc emission was measured to be 18 ppm with diesel fuel at 0 kw load; it was 62 ppm at 4.4 kw. in fig. 10 uhc emissions is decreasing with increase the substitution of .biodiesel. this belong to enough quantity of oxygen helps for complete combustion. uhc emissions for sme b20, sme b40, as well as sme b100 decreased by 15%, 27%, and 38.4%. generally, co emissions are affected by air–fuel equivalence ratio, fuel type, combustion chamber design, and atomization rate, start of injection timing, injection pressure, compression ratio, engine load and speed. figure 8 variation of bsfc with load figure 9 variation of bte with load co emission results are presented in fig.11 for different engine loads. lower co emission is noticeable at part load while the higher one is noticed at full load. as the load increased, there is an increase in co emissions and this is typical with all internal combustion engines since air–fuel ratio (a/f) decreases as the load increased (ramadhas a. et al [38]). while co emission was measured as 0.054 (% vol) with b20 sme at 0 kw load; it was 0.195 (%vol) at 4.4 kw. co emission is decreased when biodiesel percentage is increased. the oxygenated nature of biodiesel is responsible for that (gumus m. [39]). for all engine loads, co emissions for sme b20, -30 0 30 60 90 crank angle (degree) -10 0 10 20 30 40 50 h e a t r e le a s e r a te ( k j /m 3 .d e g re e ) 1.1 2.2 3.3 4.4 brake power (kw) 0.2 0.3 0.4 0.5 0.6 0.7 0.8 b s f c ( k g /k w .h ) 0.0 1.1 2.2 3.3 4.4 brake power (kw) 0 4 8 12 16 20 24 28 32 36 b ra k e t h e rm a l e ff ic ie n c y ( % ) mohamed al-dawodya, s.k. bhattib /al-qadisiyah journal for engineering sciences 12 (2019) 184–192 189 sme b40, and sme b100 reduced by 11.36%, 29.1%, and 41.7% compared to that of diesel fuel, respectively. the reduction of nox emissions are always the target for engine researchers and manufacturers. three conditions which favor nox formation are: higher combustion temperature, more oxygen content and faster reaction rate (hiroyasu et al [40]). figure 10 variation of uhc emissions with load figure 11 variation of co emissions with load nox emissions results are presented in fig.12 for different engine loads. the nox emissions increased as the engine load increased, due to the increase in combustion temperature. the emission of nox increased with the increasing biodiesel blend ratio. the oxygenated nature of sme biodiesel increases nox emission. same results is highlighted by (ozsezen a. et al [41]) and (lapuerta m. et al [42]). figure 12 variation of nox emissions with load the results of smoke emission were depicted in fig. 13 for different engine loads. the smoke emission increased with the increase in the brake power. the formation of smoke strongly depends on the engine load. as the load increases, more fuel is injected, and this increases smoke formation (metin g. et al [43]). while bosch smoke number (bsn) was measured to be 0.425 with diesel fuel at 4.4 kw, it was 0.3381 for sme b20% at 4.4 kw for 17.5 optimum compression ratio. figure 13 variation of bsn with load as illustrated in fig. 13, the smoke starts to decrease as the percentage of biodiesel increased in the fuel blend. it is mentioned that smoke decreases with high oxygen content in the biodiesel. for all engine loads, the bsn for sme b20, sme b40, and sme decreased by 20.44%, 35.78%, and 48.31%, compared to those of diesel, respectively. same observations are noted in the result of (monyem a.[44]). fig. 14(a-d) shows pressure, velocity, turbulent kinetic energy and dissipation rate contours for b20 sme respectively. theoretically the pressure is maximum at the core and decreases towards the periphery. but when flame fronts strike the cylinder walls, negative flame fronts are formed resulting in formation of localized high pressure areas near the cylinder walls as shown in fig. 14(a). also it is observed that combustion pressure decreases with increase in sme blends. the maximum pressure for neat sme is less than that of diesel by 4.6 % because of the heating values reduction for blended fuel. the base of the combustion chamber is visible in the velocity contour plots. it is evident from fig.14 (b) that the combustion velocity is higher near the fuel injector and decreases towards the cylinder walls. as the blending ratio of sme increased, the velocity decreased gradually because of higher viscosity and density of soybean biodiesel with respect to diesel fuel. the reduction in the combustion velocity is up to 6.72 % as the blending ratio of sme increased from (0-100) %. fuel-air mixing and combustion in reciprocating internal combustion engines are highly dependent on the in-cylinder turbulent flow. high turbulence results in improved mixing but the very high values of turbulence can cause knocking. turbulence in the engine produces kinetic energy also known as turbulent kinetic energy (t.k.e). as seen in fig.14(c) the t.k.e. maximum at the nozzle region and gradually decreases away from nozzle. t.k.e values reduced as a result of increase in the blend of soybean due to higher viscosity and density values of the blended fuel as compared to conventional diesel fuel. the average t.k.e is reduced by 4% 20% sme, 7.44% for 40% sme and 10.84 neat 100% biodiesel . 0.0 1.1 2.2 3.3 4.4 brake power (kw) 0 20 40 60 80 u h c ( p p m ) 0.0 1.1 2.2 3.3 4.4 brake power (kw) 0.00 0.10 0.20 0.30 c o ( v o l % ) 0.0 1.1 2.2 3.3 4.4 brake power (kw) 0.00 0.10 0.20 0.30 0.40 0.50 0.60 b o s c h s m o k e n u m b e r 0.0 1.1 2.2 3.3 4.4 brake powre (kw) 0 500 1000 1500 2000 2500 3000 n o x ( p p m ) experimental results 1500 rpm, 17.5 cr diesel sme b20 sme b40 sme b100 190 mohamed al-dawodya, s.k. bhattib/al-qadisiyah journal for engineering sciences 12 (2019) 184–192 figure 14(a) pressure contour for b20 sme velocity figure 14(b) velocity contour for b20 sme figure 14(c) turbulent kinetic energy contour for b20 sme figure 14(d) turbulent dispassion rate contour for b20 sme it can be observed from fig. 14(d) that turbulent dissipation rate (t.d.r) increases in the nozzle region and it highly depends on the t.k.e. it promotes the rate of combustion. by increasing the percentage of sme blends causes a reduction in the rate of dissipation energy by 2 %. fig. 15(a-b) shows nox and soot mass fraction contours for b20 sme respectively. it is noticed from fig. 15(a) that peak nox value increases near the wall due to the formation of localized high temperature areas near the combustion chamber walls. the nox emissions for soybean biodiesel blends are higher than that of base line diesel fuel. this is related to the higher combustion temperature and higher oxygen content in the biodiesel as compared to diesel fuel which in turn enhanced nox formation. fig. 15(b) shows the soot mass fractions for b20 sme. soot levels for b20, b40, and b100 are less than diesel by 21.61 %, 36.33 %, and 41.41 % respectively. it is mentioned early that lower c/h ratio together with high oxygen content of biodiesel are the main reasons of reducing soot formation figure 15(a) nox emissions for b20 sme figure 15(b) soot emissions contour for b20 sme 6. verification the experimental investigation is compared with cfd analysis as shown in table 5. the comparison between the two was found in good agreement with a slight difference. mohamed al-dawodya, s.k. bhattib /al-qadisiyah journal for engineering sciences 12 (2019) 184–192 191 table 5, verification of results between diesel and b20 sme fuel δ % peak pres. δ % peak temp δ % veloc ity δ % t.k.e δ % t. d.r δ % nox δ % soot diesel b20sme -1.31 +2.27 -1.53 -4 +0.21 + 6 -21.61 b40sme -3.5 +4.50 -3.82 -7.44 -1.22 +14.15 -36.3 sme -4.6 +5.86 -7.61 -10.8 -2 +27.77 -41.41 7. 7. conclusions 7.1. conclusions from the experimental investigation 1increasing load reported remarkable increase in pressure, brake efficiency and smoke while uhc as well as bsfc is decreased. 2earlier combustion start for all biodiesel blends. 3bte is slightly reduced and fuel consumption is increased when sme percentage increased 4uhc is reduced with b100 % sme by 38.4% as well as the emission of co is decreased with b100 % sme 41.7% respectively. 5the measured bsn for sme 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[44] monyem a. the effect of biodiesel oxidation on engine performance and emissions. ph.d. dissertation, department of mechanical engineering, iowa state university, ames, ia; (1998). http://www.intechenergy.com/ article al-qadisiyah journal for engineering sciences 14 (2021) 006–013 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: amarkreem24@gmail.com(ammar k. al-najar) https://doi.org/10.30772/qjes.v14i1.713 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. numerical analysis of one-way continuous slab with partial corrosion strengthened with deferent material ammar k. al-najar a, labeeb s. al-yassri b apost graduate student , university of al-qadisiyah, college of engineering, iraq. blecturer , ph.d. the university of al-qadisiyah, college of engineering, iraq. a r t i c l e i n f o article history: received 10 november 2020 received in revised form 11 april 2021 accepted 15 april 2021 keywords: numerical analysis, abaqus, corrosion, construction joint, negativ reinforcement, cfrp, nsm, steel plate a b s t r a c t this paper investigates numerically the combined effects of a construction joint and reduction in the crosssection area of negative reinforcement in one-way continuous slab on the structural behavior and the efficiency of three types of strengthens techniques. in this paper, the modles were greated by abaqus (software) is used to numericaly represent the specimens and simulate the applied loading. this numerical study's models represent six one-way continuous slabs, as a part of a expermentail study. the specimen's dimensions were (2200 mm in length, 500 mm width ,and 100 mm thickness). five of the six models had a vertical construction joint and reduced the negative reinforcement steel bars' cross-sectional area. the sixth specimen used as refreance. the proposed strengthening technique were: carbon fiber reinforced polymers strips, 6 mm carbon fiber reinforced polymers bars near surface moutain technique and steel plates. all the proposed strengthening's applied to the tension side on the top face at the internal support. the program outcomes are represented visually as stresses distribution diagrams,load-deflection curves, and cracks pattern. the results from the numerical analysis compared to the experiment results. in the experiment, the reduction in the cross-section area resulting from partial corrosion happened in one span due to the outdoor atmosphere's exposure because of the stoppage in the concrete pouring, which also resulted in forming the construction joint. the results highlighted the construction joint's effect and the steel cross-sectional area reduction on the ultimate load and the deflection. the proposed strengthening methods improved the member's overall responses, and there was a good convergence between the numerical and experimental works that verify the specimens' observed behavior. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction buildings and bridges need rehabilitation or strengthening for different causes. the composite materials strengthen different structural members such as beams, slabs, and masonry walls meier [1]. a study conducted by elsanadedy et al.[2] to analyz by using the finite element method of frp utilization to enhance the one-way slabs flexural strengthening. eight specimens were used. two are considered as a reference without strengthening. two samples were strengthened with five cfrp strips (50 mm width and 1080 mm length). two specimens strengthened with five (200 mm width and 1080 mm long) cfrp strips, and the last two samples strengthened with five gfrp strips (200 mm width and 1080 mm long). all strengthening externally bonded to the tension face. the ls-dyna was a computer software used to execute the analysis. the research came up with the conclusion that the model was suitable to simulate the experimental work. according to the comparison between the numerical and experimental results, the model can further investigate other parameters. foret and limam [3] numerically analyzed four specimens of two-way reinforced concrete slabs to examine the efficiency of strengthening them with cfrp nsm bars and cfrp sheets to increase the http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 7 flexural strength. the strengthening was 8 mm cfrp bars and 50 mm width cfrp sheets. a composite orthotropic plate model with a 2d finite element was created by the researcher to simulate the specimen's elastic behavior. after the numerical linear model was executed, a comparison between the experimental and the numerical results have done. according to the results, there was an excellent convergence between the experimental and numerical work. the model was reliable. bouguerra et al. [6] studied experimentally and numerically using frp to rehabilitate the damaged bridge deck slab due to corrosion. a 35 mpa concrete used to cast a 2500 mm square slab with 175 mm thickness subjected to point load in the middle in the experimental part. the numerical part was modeled the slab with the fe model by adina 8.4 software. the study found a remarkable convergence regarding for ultimate load and deflection between the experimental and numerical work. l-yassri et al. [9] experiment using the hybrid reinforcement in hollow-core concrete slabs in the structure behavior. the main parameter was replacing conventional reinforcement with cfrp bars with a percentage of replacement (0, 50, and 100%). the study concluded that using cfrp bars with a steel bar was more effective than using the only cfrp bars, and the shear capacity was slightly influenced by using the cfrp bars, while there was a decrease in the stiffness of specimens. ranjitham and manjunath [11] numerically investigated the use of bubble deck slab as a replacement for conventional kind of slabs. the model greated and analyzed by ansys. the numerically result compared with the experimental result in regarding stress and deformation. the study found that both numerical and experimental model showed higher load-bearing capacity. there was an improvement in the slab behaviour in regard to deflection and weight parameter. this paper adopts experiment results and structural details of a study conducted by al-najar and al-yassri [12]. a comparison between the numerical results and the adopted experiment was made. the experimental specimens of the adopted study consist of six one-way continuous slabs. those slabs were tested under a two-point monotonic load until complete failure-the specimens cast with concrete, with an average 28-day compressive strength equal to (32.1 mpa). specimen dimensions and reinforcement details are illustrated in fig. 1 five of six specimen had a vertical construction joint at the internal support and negative reinforcement loss in one span due to corrosion, while the sixth was without construction joint and steel losses. the steel losses of negative reinforcement, illustrated in table 4. in the experimental study, three types of strengthening suggested compensating for a construction joint's presence and the steel area losses. they were: two of 50 mm width of cfrp strips, two of 6 mm diameter cfrp bars applied with nsm technique, and two of 50 mm width and 5 mm thickness of steel plates. all proposed strengthening was applied to the tension face at internal support and extend in the two spans with a =l/3=350 mm aligned with the continuity axis of the specimens table 1: specimens classification specimens symbols corrosion and construction joint strengthening s-o-1 ----------none- s-o-2 (reference) partial corrosion in the negative reinforcement and joint ----none -- s-o-3 (reference) partial corrosion in the negative reinforcement and joint ----none-- s-o-4 partial corrosion in the negative reinforcement and joint strengthened with cfrp strips s-o-5 partial corrosion in the negative reinforcement and joint strengthened with cfrp 6 mm bars nsm s-o-6 partial corrosion in the negative reinforcement and joint strengthened with steel plates 2. numerical analysis modeling 2.1. parts, properties, and assembly abaqus [13] the finite element analysis program used to create the model representing the experimental study's specimen. the model creation process required drawing the specimens' component using the software's toolbars, concrete, reinforcements, the strengthening, loading, and supporting parts with its dimensions and exact location. material properties, either elastic or inelastic, gained from the control test assigned to the model's parts after drawing them. to make the numerical analysis represent the specimen's actual structural behavior, the model should be as far as possible is identical to the experimental specimens regarding material properties dimensions and loading conditions. all specimen parts are resembled in fig. 2), and the losses in steel bars due to partial corrosion represented in the numerical study by reducing the bar diameter, as shown in fig. 3. figure 1:specimens dimension and reinforcement details [12] 8 ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 2.2. interaction between the parts to model a composite member and after drawing each element separately and gave each one a proper section, it was necessary to connect the parts by assigning the suitable connect type. (see table 2). table 2: contact between the different parts parts type of interaction concrete-steel bars embedded concrete-loading plate rigid body concrete-cfrp bars embed concrete-steel plate surface to surface (cohesive) concrete-cfrp strips surface to surface (cohesive) old concrete-new concrete surface to surface (cohesive) 2.3. finite element modeling concrete, loading plate, support, and other parts were modeled in the finite element program (see table 2). the concrete elements modeled using (t3d2) 3d 8 nodes bricks elements to gain sufficient distribution of stress while the steel bars meshed to linear truss element (2 nodes elements) [14, 15]. depending on the convergence study for mesh, 35 mm mesh size adopted. table 3: finite element modelling part element type (three degree of freedom for each node) concrete linear hexahedron, type c3d8 ( 8 node ) support linear hexahedron, type c3d8( 8 node) loading plate linear hexahedron, type c3d8( 8 node) steel bars linear line, type t3d2( 2 node) cfrp bars linear line, type t3d2(2 node) steel plate linear hexahedron, type c3d8( 8 node) cfrp strips linear quadrilateral, type s4r( 4 node ) 2.4. loading and boundary conditions the loading plates were square steel plates with 100 mm and 100mm wide placed at mid-distance between supports and extended along slab width. the load in abaqus presented as uniform pressure after. boundary conditions applied at supports (10 mm thickness) , which was three paces in the experiment. the first support was in the begging, the second in the middle, while the third was in the end. the displacement was constrained for the first support in three directions x, y, and z, while the other two were in one direction y, the rotation was allowed in the three supports (see fig. 4). 2.5. analytic results after completing all requirements and all the needed data to run the simulation, the program analyzes. the result was interpreted visually by the load-deflection curve and deformed shape. according to the changes in parameters ( corrosion percentage and the strengthening methods ), the ultimate load and deflection will also vary. the convergence between the numerical and experimental results indicated the reliability of the model. tables 4 and 5 show the ultimate load, deflection, and failure mode experientially and numerically. figures 5 to 9 show a load-deflection curve for each specimen. in experimental and numerical analysis, the same symbolic schema was adopted. in the (s-o-x) symbol, the "s" refers to member type, which is a slab, the "o" refers to the type of slab which was a one-way slab, and the "x" is a variable ranged between 1 to 6 (see table 3). table 4: experimental and numerical ultimate load specimen losses in steel area % ultimate load (kn) exp.[12] num. s-o-1 0.00% 110 111 s-o-2ands-o-3 51.57% 75 78.8 s-o-4 54.30% 116 122 s-o-5 48.92% 117 114 s-o-6 0.4517 112 109.6 table 5: experimental and numerical deflection at ultimate load and failure mode specimen deflection at ultimate load (mm) failure mode exp. num. exp. num. s-o-1 11.7 7.3 flexural tensile failure flexural tensile failure s-o-2and s-o-3 4.3 4.4 flexural tensile failure flexural tensile failure s-o-4 9.7 9.8 de-bond of cfrp strips followed by flexural tensile failure de-bond of cfrp strips followed by flexural tensile failure figure 2: parts and assembly figure 4: loading and boundary conditions figure 3: change in the bar diameter due to corrosion ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 9 s-o-5 12.1 10 de-bond of cfrp bars followed by flexural tensile failure de-bond of cfrp bars followed by flexural tensile failure s-o-6 13.2 11 de-bond of steel plates followed by flexural tensile failure de-bond of steel plates followed by flexural tensile failure figure 6: experimental and numerical load-deflection curves for so-2 and s-o-3 specimens figure 7: experimental and numerical load-deflection curves for so-4 specimen figure 8: experimental and numerical load-deflection curves for so-5 specimen figure 9:experimental and numerical load-deflection curves for so-6 2.6. cracks pattern according to observations from the experimental test, the tension cracks in one-way slabs were perpendicular to the slab axis, also concentrated in the bottom face and extended to slabs sides in addition to the tension zone of the negative moment at the internal support, which results in the opening of the joint. the analytical part showed that the damaged tension areas, which can develop into cracks, were identical to the experimental work. figure 5: experimental and numerical load-deflection curves for so-1 specimen figure 10:experimental and numerical cracks pattern of s-o-1 specimen 10 ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 2.7. failure mode the experiment specimens failure mode was similar: the strengthening debond from concrete followed by flexural failure for strengthened specimens. it was a flexural failure for the not strengthened specimens. in the numerical study, the tension damage areas (which indicate the failure) spread similarly to the experimental (see figures 15 to 19). figure 11:experimental and numerical cracks pattern of s-o-3 specimens figure 12:experimental and numerical cracks pattern of s-o-4 specimen figure 13:experimental and numerical cracks pattern of s-o-5 specimen figure 14:experimental and numerical cracks pattern of s-o-6 specimen figure 15: failure mode of s-o-1 specimen ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 11 2.8. ises stresses (von mises theory) the failure is happening when the material was subjected to increasing in load, which leads eventually to fail or is a state that prevents the structure from the purpose which builds for it. failure, in general, can be defined as fracture with very little yielding, permanent deformation. fracture is one of many modes for failure: a separation of the object for two or more parts by a brittle or ductile mechanism. from the figures (20 to 24), it becomes evident that the strengthening method and losses in steel have been influenced by the distribution of stresses. the areas surrounding the loading plates show higher stresses, and this is similar to the experimental work. figure 17: failure mode of s-o-2 and s-o-3 specimens figure 16: failure mode of s-o-4 specimen figure 19: failure mode of s-o-6 specimen figure 20: mises stresses in s-o-1 specimen figure 18: failure mode of s-o-5 specimen 12 ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 3. parametric study in each experimental work, increasing the targeted parameter will increase the work complexity and lead to the result's interference, making it hard to connect the unique variables to its influence. since we found that the model is reliable in this study will test the influence of changing variable and its influence on the model, which reflects approximately the actual behavior. the one-way slabs (s-o-3) chosen to investigate the difference that could be happening if the compressive strength increased to 40,50,60,70 mpa (see fig. 25) table 6:parametric study results 𝑓𝑐 (𝑀𝑃𝑎) 𝑃𝑢 (𝑘𝑁) ∆𝑢 (𝑚𝑚) (𝑃𝑢∗∗ − 𝑃𝑢∗) 𝑃𝑢∗ ⁄ (%) (∆𝑢 ∗∗ − (∆𝑢 ∗ ) (∆𝑢 ∗∗∗⁄ (%) 32 78.8 4.42 ------- ------- 40 80 4.20 1.52 -4.84163 50 80.3 4.25 1.9 -3.84615 60 80.8 4.37 2.54 -1.13122 70 81.8 4.38 3.81 -0.90498 𝑃𝑢∗ = 32 (𝑀𝑃𝑎) 𝑃𝑢∗∗ = 𝑃𝑢𝑓𝑐(40−70) (𝑀𝑃𝑎) ∆𝑢 ∗ = 4.42(𝑚𝑚) ∆𝑢 ∗∗= ∆𝑓𝑐(40−70)(𝑚𝑚) figure 21: : mises stresses in s-o-2 and s-o-3specimens figure 22: mises stresses in s-o-4 specimen figure 24: mises stresses in s-o-6 specimen figure 23: mises stresses in s-o-5 specimen 0 10 20 30 40 50 60 70 80 90 0 1 2 3 4 5 6 load (kn) deflection mm fc 32 fc 40 fc 50 fc 60 fc 70 figure 25: load-deflection curves for parametric study ammar k. al-najar, labeeb s. al-yassri /al-qadisiyah journal for engineering sciences 14 (2021) 006–013 13 increasing the compressive strength will increase the ultimate load and reduce the deflection. still, this increase will not compensate for reducing the corrosion and the construction joint's presence. 4. conclusions 1) a good convergence regarding the ultimate load, deflection, and failure mode were between the numerical and experimental works. 2) abaqus's created model predicted to an acceptable degree the structural behavior of a member and highlighted the potential failure regions with high accuracy. 3) according to the gained results from the numerical analysis found that the model was reliable and could implement with confidence. 4) the numerical analysis found that reducing the cross-section area of steel bars and construction joints led to a reduction in the ultimate capacity compared to the not corroded specimen (28.8%). the experiment was (31.8%). 5) according to the parameter study, increasing the 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[16] j. ye, structural and stress analysis. taylor & francis, 2008. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 40 -qadisiyah journal for engineering sciences . all rights reserved hardware implementation of it2flc using fpga for control applications assist. prof. dr. mohammed y. hassan university of technology, control and systems department, baghdad, iraq e mail: 60003@uotechnology.edu.iq saif faris abulhail university of technology, control and systems department, baghdad, iraq e mail: saifabulhail80@gmail.com lecturer dr.waleed fawwaz shareef university of technology, control and systems department, baghdad, iraq e mail: 60026@uotechnology.edu.iq received on 4 december 2017 accepted on 22 january 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.519 abstract: interval type2 fuzzy logic control (it2flc) has been applied to a number of industrial, medical, home and military applications. hardware implementation of it2flc can be achieved in a number of ways. one of these ways is the use of a field programmable gate array (fpga). in this paper, the design and implementation of an it2flc using fpga has been presented. the proposed controller is of mamdani type. it works in different structures (p/pi/pd/pid like it2flc) depending on two control lines, different number of triangular shape memberships (2-7) depending on three control lines, six tunable gains and within a range of sampling time of (0.01-1024) seconds. three type reduction algorithms are used and it is found that the enhanced iterative algorithm with stop condition (eiasc) produced the minimum reduction in fpga size. thus less execution time. the reduction size is about 75% than karnick mendel (km) and is about 3% than enhanced km (ekm). linear and nonlinear models are used to test the designed controller. gains are tuned manually to reach minimum overshoot, settling time and steady state error. simulation and implementation results showed that the proposed controller works in an efficient way under no-load, load and uncertainty in the nonlinear model parameters. keywords: footprint of uncertainty, karnick mendel, enhanced karnick mendel and fpga mailto:60003@uotechnology.edu.iq mailto:saifabulhail80@gmail.com mailto:60026@uotechnology.edu.iq al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 41 -qadisiyah journal for engineering sciences . all rights reserved nomenclatures 1. introduction type2iflc containifootprintiof uncertaintyi(foui) that is able toihandle the numerical uncertainties, nonlinearities and linguisticmassociatedi with the inputs and outputs. hassan and sharif [1], in 2006 proposed a proportional-integral-derivative type1 flc (pidt1flc). fuzzy sets and programmablemrule table were designed usingmvery high descriptionmlanguage (vhdl) for implementation on fpga device. the controller could serve as allproportional-derivative t1flc (pdt1flc), proportional-integral t1flc (pit1flc), or proportional-integral-derivative t1flc (pidt1flc). two versionsllof this controller were designed; the first onellis 6-bits fpga-based design, which uses 6 bits for i/ollvariables, while the second one is 8-bit fpgallbased design, which uses 8 bits.llthe results of the simulation showed that the 8-bit fpga-based design is superior to the 6-bit fpga-based design. maldonado, et al. [2], in 2011 presented the design of the optimal t2flc obtained using genetic algorithms (ga) for optimization. the optimization of triangular and trapezoidal membership functions (mfs)llof a fuzzy system is done for hardware representations such as the fpga. the ga uses only certain points of the mfs, while the fuzzy rules did not symbols definition �̃� type-2 fuzzy sets 𝑓 𝑛 upper firing level �̃�𝑛 fuzzy rule number 𝐹 friction torque 𝐹𝑐 coulomb friction 𝑔 gravity 𝐽 moment of inertia �̃�𝑖 𝑛 inputs fuzzy sets 𝑒(𝑘) sampled error 𝑓 𝑛 lower firing level 𝑦 𝑛 lower end point 𝑦 𝑛 upper end point 𝐹𝑛 firing interval 𝑌𝑐𝑜𝑠 centre of sets type reduction 𝑦𝑙 left end point 𝑦𝑟 right end point r right switch point 𝐿 left switch point 𝑈 control action 𝜇 �̃�𝑖 𝑛 lower membership function of input �̃�𝑖 𝑛 𝜇 �̃�𝑖 𝑛 upper membership function of input �̃�𝑖 𝑛 𝐽𝑥 type1 fuzzy set 𝐹𝑂𝑈(�̃�) upper footprint of uncertainty al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 42 -qadisiyah journal for engineering sciences . all rights reserved change. the ga was tested in a t2flc to regulate the direct current motor speed, using the matlab/simulink and vhdl code. comparisons were made between the t1flc versus t2flc, to evaluate the difference in performance of both types of controllers. mani and barjeev [3], in 2012 developed the implementation of a t1flc through the use of the vhdl code. flc is designed for an armature control dc motor speed control. vhdl has been used to develop flc on fpga. a sugeno type flc structure has been used to obtain the controller output. the controller algorithm developed, synthesized, simulated and implemented on fpga spartan 3e xc3s500e-4fg320llboard. panda, et al. [4], in 2012lldesigned an it2flc for an automaticllvoltage regulator system. for controller design, memberships of system variables are represented using interval value fuzzy sets. thelleffectiveness of this controller has been investigated through simulation studies. the simulation showed performance of the controller and compared with a pid controller. jun, et al. [5], in 2014 presented a newllfeed-water controller under thellautomatic power regulatingllsystem for an advancedllboiling waterllreactor. the new feedllwater controller is designed by using a rule-based hierarchicalllflc and is implemented by using the fpga technology. the results demonstrated that the fpga-based hierarchical flc is a practical approach forllautomatic power operations inlladvanced nuclear power plant applications. schrieber and biglarbegian [6], in 2015 developed hardware implementation and performance comparison ofllit2flc for real-time applications. it2flc with parallel processing usingllfpga was designed and implemented. design and implementation are using three different inference mechanisms of it2flc on hardware. li, et al. [7], in 2015 designed sampled data controller for it2flc withllactuator fault. the it2flc and the it2 state-feedbackllcontroller share different mfs. it was found that there has not been a major focus on the design and implementation of p/pi/pd/pid like it2flc usingllfpga chip. in this paper, an it2flc can work with different number of memberships and several type reduction algorithms with highllresolution data. several promisingllapproaches havellused other types in the design of controllers. the proposed it2flc is designed for controlling efficientlyllto the real systems and to achieved smallllfpga size and as a result, less execution time must be achieved vs. acceptable accuracy. hardware setup and experimental results of the linear and nonlinear models are explained. the rest of this paper is organized as follows: section 2 introduces to an it2flc and its computations. section 3 describes the designed controller, including the performing of an it2flc with different structures and type reduction algorithms. section 4 illustrates the implementation and hardware setup of an it2flc, including altera de2 board, national instrument (ni) 6212 device. it describes the connections between these devices with pc using hardware in the loop approach. section 5 shows the practical results of the designed it2flc that is connecting with linear and nonlinear models. section 6 presented the conclusions from this work. 1. interval type2 flc type2ifuzzyllsetsimembershipllfunction are fuzzy and contain foullthat handles andllmodels the uncertainties, nonlinearities andlllinguistic relatedllwith the inputs and output of the flc. foulis theiarea betweeni lower membership and upper membership. it is allowingieachllinput toihave two membershipllgrade values related with it; an upper mf (umf) and lower mf (lmf). there are two types of t2flc: mamdani type and takagillsugenollkang (tsk) type. the differencellbetween these two types, the sugeno output membership fucntion is linear or constant and the mamdani output is shape thellmembership. mamdani type needs type reducer methodllwhile the takagi sugeno type does not need typeireduction operation. the structure of the it2flc is shown in figure (1) [8, 9]. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 43 -qadisiyah journal for engineering sciences . all rights reserved figure 1: structure of t2flc. 1.1 computations of it2flc an it2flc icontaining atileast one interval fuzzy set withoutiloss ofigenerality. if an it2 flc consisting of nirules, the rule base has the followingiform: �̃�𝑛 ∶ 𝑦 = 𝑌𝑛 if 𝑥1 is �̃�1 𝑛 and … and 𝑥𝐼 is �̃�𝐼 𝑛, where 𝑖�̃�𝑖 𝑛 (𝑖 = 1𝑖 . … . 𝑖𝐼𝑖) are it2 fuzzyisets. in addition, 𝑌𝑛 = [𝑦 𝑛 𝑖. 𝑦 𝑛 ] is an interval that can be understoodias the centroid of a consequent it2 fuzzy set or theisimplest tsk model. each rule consequent is represented by a crisp number in many applications [10]. for an inputivector 𝑋′ = (𝑖𝑥′1 . 𝑥′2 . …...𝑖𝑥′𝐼 ) . typicalicomputations inian it2flc include the followingistepsi[10]: 1) compute themmembership interval of 𝑥′𝑖 onmeach �̃�𝑖 𝑛 , [ 𝜇 �̃�𝑖 𝑛 (𝑥 ′𝑖 ) . 𝜇 �̃�𝑖 𝑛 (𝑥 ′𝑖 )] , 𝑖 =1, 2.…. 𝐼. 𝑛𝑖 =1,2.….in. 2) calculate the firing interval of the 𝑛𝑡ℎirule, 𝐹𝑛: 𝐹𝑛 = [𝜇 �̃�1 𝑛 (𝑥 ′1 ) × … × 𝜇 �̃�𝐼 𝑛 (𝑥 ′𝐼 ) ‚ 𝜇 �̃�1 𝑛 (𝑥 ′1 ) … × 𝜇 �̃�𝐼 𝑛 (𝑥 ′𝐼 )] ≡ [𝑓 𝑛 . 𝑓 𝑛] . 𝑛 =1,2…n. 3) the thirdmstep is that performmtype reduction. the mostmcommonly usedi onemis the centeri of sets typeireducer: 𝑌𝑐𝑜𝑠 = ∑ 𝑌𝑛𝑁𝑛=1 ∑ 𝐹𝑛𝑁𝑛=1 = [𝑦𝑙 . 𝑦𝑟 ] (1) 𝑦𝑙 = 𝑚𝑖𝑛 𝑘∈[1.𝑁−1] ∑ 𝑦 𝑛 𝑓 𝑛 +∑ 𝑦 𝑛 𝑓𝑛𝑁𝑛=𝑘+1 𝑘 𝑛=1 ∑ 𝑓 𝑛 +∑ 𝑓𝑛𝑁𝑛=𝑘+1 𝑘 𝑛=1 (2) 𝑦𝑟= 𝑚𝑎𝑥 𝑘∈[1.𝑁−1] ∑ 𝑦 𝑛 𝑓𝑛+∑ 𝑦 𝑛 𝑓 𝑛𝑁 𝑛=𝑘+1 𝑘 𝑛=1 ∑ 𝑓𝑛+∑ 𝑓 𝑛𝑁 𝑛=𝑘+1 𝑘 𝑛=1 (3) in equation (2) and equation (3) 𝐾 is a potential switchipoint. 4) compute themdefuzzified output as: 𝑦 = (𝑦𝑙 + 𝑦𝑟)/2 (4) 2. controller design the general block diagram of the proposed controller is shown in figure (2). this proposed it2flc is designed by combining the advantages of fuzzy inference and different structures of controller. the type of the controller is selected using two bits selection lines‚ as illustratedllin table (1). structure design of thellproposed it2flc is shown in figure (3). the inputs to the controller are: input-output tunable gains‚ al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 44 -qadisiyah journal for engineering sciences . all rights reserved sampling time‚ set-point and the controlllsignal. the output of the controller is the control action signal. the range of thelluniverse of discourse isllwithin [−1 𝑡𝑜 1] for each input and output. the proposed controller can work with (2-7) input-output triangular shaped mfs. the user can select the number of mfs using three control signals (c3‚ c4 and c5) that is listed in table (2). the shapes of mfs design are shown in figure (4). the defuzzification technique is selected as centroid method. the sampling time is selected by user depending on the model that is connecting with the proposed controller. rule-base is written in a lookup table. this rule-base is designed by the user and located in the controller. mamdanitype is used to perform fuzzy inference of the controller. three algorithms km‚ ekm andlleiasc are used to implement the type reduction method of the it2flc. ekm has threellimprovements over the km algorithm. first‚ a betterllinitialization is used to reduce the number of iterations. then‚ the terminationllcondition of the iterations is changed to removellone unnecessarylliteration. finally‚ a subtlellcomputing technique is used to reduce the computational cost oflleach iteration. eiasc algorithmllenumerate the switchllpoint for 𝑦𝑙 from 1llto n−1 until 𝑓𝑙(𝑘) stopslldecreasing, at whichllpoint 𝑦𝑙 is obtained. similarly, llthey enumeratellthe switch pointllfor 𝑦𝑟 from 1 to n−1 until 𝑓𝑟(𝑘)stops increasing, at which point 𝑦𝑟is obtained. the comparisons among three type reduction algorithms are listed in table (3). it can be concluded from table (3) that using ekm algorithm gives small fpga chip size than km algorithm and as a result generates less execution time and using eiasc algorithm produces small fpga chip size than ekm algorithm and as a result generates less execution time. it can be notice that the use of eiasc with the proposed controller give us less fpga size. thus‚ eiasc will be used in the implementation of the it2flc. the programs arellwritten using matlab / simulink and matlab functions‚ then converted into vhdl and verilog formats using hdl coder. hdl coder technique has many restrictions and limitations in matab functions‚ such as (for loop‚ if statement‚ floating point and find function). therefore; these limitationsllwere solved by designing matlab functions that overcome the hdl coder restrictions. the program is generated to achieve minimum fpga size and as a result‚ less execution time. furthermore‚ in order to design a pid like it2flc‚llt.is.required to design..a fuzzy inference system withllthree inputs thatllrepresent the proportional‚ derivative andllintegral components. a fuzzyllcontroller with three inputs mayllnot beipreferred‚ because it islldifficult to design. foriexample‚ if eight fuzzy sets are used for each input‚ then a (8*8*8=512) rules willube required for the controller. instead‚ pid likellt2flc canube designed asia parallelistructure of a pd like it2flc and a pi like it2flc. the outputiof the pid like it2flc is formed byialgebraically summing the outputs of theitwoifuzzy control structure. this method will reduce the number of rules required to (8*8+8*8=128) rules only‚ as shownllin figure (5). a pd like it2flc may be employed to serve as pi like it2flcllin incremental form. equation (5) shows a pdllcontroller equation obtained in a positionllform‚ while equation (6) shows a pi controller equation in an incremental form in discrete time domain: 𝑢𝐷(𝑘) = 𝐾𝑃 𝑒(𝑘) + 𝐾𝐷 ∆𝑒(𝑘) (5) ∆𝑢𝐼(𝑘) = 𝐾𝑃 ∆𝑒(𝑘) + 𝐾𝐷 𝑒(𝑘) (6) 𝑢𝐼(𝑘) = 𝑢𝐼(𝑘−1) + ∆ 𝑢𝐼(𝑘) (7) ∆𝑒(𝑘) = 𝑒(𝑘)− 𝑒(𝑘−1) 𝑇𝑠 (8) where 𝑢𝐼(𝑘−1) is the previousllcontrol signal‚ 𝑒(𝑘)is allsampled error signal‚ 𝑒(𝑘−1) is a previous sampled errorllsignal ∆𝑒(𝑘) is the ratellof change of sampledllerror signal, 𝑇𝑠 is thellsampling time and index (k) represents the present sampling instant. now by comparing equations (4) and (5) ‚ it show that the pd likellit2flc in a position formllbecomes a pi like it2flc inllincremental form if 𝑒(𝑘) and ∆𝑒(𝑘) exchange positions‚llkd is replaced by 𝐾𝐼 and 𝑢𝐼(𝑘) is replaced by ∆𝑢𝐼(𝑘) . the output of a pi likellit2flc is obtained by summing the changellof control signal ∆ 𝑢𝐼(𝑘) and the previous control signal𝑢𝐼˳. the outputs of the pd likellit2flc and pilllike it2flc are summedlltogether to form the pid like it2flc output. sincelleach pd likellit2flc has its ownllgains and rules‚ the controller design can act as a p like it2flc by setting kd of pd and pi like it2flc to zero‚ a pd like it2flc‚ a pi likellit2flc‚ and a pidlllike it2flc depending on twollbits control signal c1 and c2 as illustrated previously. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 45 -qadisiyah journal for engineering sciences . all rights reserved figure 2: general block diagram of the controlled system figure 3: structure of the proposed controller three mfs (b ) two mfs (a) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 46 -qadisiyah journal for engineering sciences . all rights reserved six mfs (d ) four mfs (c) five mfs (f)seven mfs (e) figure (4): mfs design (a) three inputs pid like it2flc (b) two inputs pid like it2flc figure 5: minimizing rule-base of pid like it2flc a) b) al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 47 -qadisiyah journal for engineering sciences . all rights reserved 3. implementation of the proposed it2flc 3.1 altera development fpga board altera de2 board is shown in figure (6), it providesmtwo 40-pin expansion headers. each headermconnects directly to 36 pins on themcyclone ll fpga, and also provides dc +5v (vcc5) and two gnd pins [11]. figure 6: altera fpga board 3.2 ni usb 6212-daq device data acquisitionllsystems is shown in figure (7), it incorporate signals, llsensors, actuators, signalllconditioning, data acquisitionlldevices and application software. ni usb-6212 daq is a simple and lowllcost multifunction i/olldevice from national instruments. figure 7: ni daq 6212 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 48 -qadisiyah journal for engineering sciences . all rights reserved 3.3 hardware connections the advantage of ni usb 6212 daq in this design is to transfer data between the pc and altera de2 board. verilog hdl language is used in quartus ii software program to implement the proposed it2flc. verilog code that represents the proposed it2flc is synthesized and downloaded into the fpga using quartus ii 13.0 web edition software (64-bits). quartus ii summary report, shown in figure (8), describes the requirement fpga gates. the connection between the model and the proposed controller is using hardware in the loop approach as shown in figure (9), where the model is simulated in matlab and the controller is working in fpga altera de2 board. ni usb 6212-daq acts as the interfacing between pc and the proposed controller. linear and nonlinear models are simulated in the matlab/ simulink environment. data acquisition toolbox software is installed in (matlab 2017a) to provide a set of tools for analog input, analog output, and digital input/output. the controlllaction generated fromllthe proposed controller isllsent to the pcllin a parallel way through ni usb 6212-daq device. ni usb 6212-daq is sending it in serial mode to the pc usingllusb port. thellfeedback signal is returned to the controller through daq device using usb port. the required altera de2 pins are connected with ni usb 6212-daq pins using wires. thirty-two wires are connected between ni usb 6212 daq and altera de2 board, 16 for inputs and 16 for outputs. the pins from (a0 – a15) are setting as output (control action) and (a15 -a31) are setting as input (actual output). two switches (c1) and (c2) are using to select the type of the proposed controller as illustrated in table (1). three switches (c3, c4 and c5) are used to select the number of mfs, see table (2). one pushbottom is used to reset the controller. finally, the photograph of the hardware setup is shown in figure (10). figure 8: quartus ii summary report figure 9: hardware in the loop connections al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 49 -qadisiyah journal for engineering sciences . all rights reserved figure 10: connections between ni usb 6212-daq and altera de2 board 4. practical results in order to examinellthis proposed controller‚ linear and nonlinear models are used. in this designllsamplinglltimellisllsetlltoll0.01llseconds.inllorderlltollreachllminimumiovershoot‚iminimum.undershoot‚ minimum settling time‚ minimum steady state error and minimum structure design‚ trial and error method is used to tune the gains and rules as shown in table (4) to obtain the best response. the desired position is chosen as a unit step value. seven triangular memberships are chosen for testing purposes. 4.1 linear model a linear model is selected as an example and represented by the following transfer function: 𝑦(𝑧) = 0.00995𝑧 𝑧−0.99 (9) gains are tuned manually and they are listed in table (5). the unit step response of this model using p like it2flc as shown in figure (11), pd like it2flc as shown in figure (12), pi like it2flc as shown in figure (13) and pid like it2flc is shown in figure (14). al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 50 -qadisiyah journal for engineering sciences . all rights reserved (a) with no load (b) with load =10% from step input figure 11: output time response of the linear model controlled by the p like it2flc (a) with no load (b) with load =10% from step input figure 12 : output time response of the linear model controlled by the pd like it2flc al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 51 -qadisiyah journal for engineering sciences . all rights reserved (a) with no load (b) with load =10% from step input figure13: output time response of the linear model controlled by the pi like it2flc (a) with no load (b) with load =10% from step input al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 52 -qadisiyah journal for engineering sciences . all rights reserved figure 14: output time response of the linear model controlled by the pid like it2flc 4.2 nonlinear servo motor model the dc motor is a particular sort of motors, which is classified as one of the principal machines to generate mechanical power from electrical power. the mathematical model of servoimotor system isirepresented by aisecond order dynamic system withifriction as follows [12]: 𝐽𝑥�̈� = 𝑢𝑖 − 𝑖𝐹 − 𝑇𝐿𝑖 (10) whereithe moment of inertia is represented by 𝐽 ; the acceleration is represented by �̈� . theicontrol inputitorque isirepresented by . 𝐹 is the friction torque and 𝑇𝐿 is the load torque. the friction torque is represented by static friction phenomena. which include: coulomb friction, stictionifriction, and theiviscousifriction. i.e.. [14]. 𝐹 = {𝐹𝑠 exp (− ( �̇� 𝑥�̇� ) 2 ) + 𝐹𝑐 (1 − exp (− ( �̇� 𝑥�̇� ) 2 )) + 𝜎|�̇�|} ∗ 𝑠𝑔𝑛(�̇�) (11) where the coulombifriction is represented by 𝐹𝑐 . the stiction friction isirepresented byi𝐹𝑠 . the stribeck velocity is represented by 𝑥�̇� . and 𝜎 is the viscous friction coefficient [12]. gains are tuned manually and they are listed in table (6).the unit step response of this model using pid like it2flc without applyinglluncertainty to the system is shown in figure (15). moreover, the unit step response with applying uncertainty about 10% from unitllstep input to the friction and moment of inertiallparameters is shown in figure (16). … (a) with no load (b) with load =10% from step input figure 15: output time response of the servo motor controlled by the pid like it2flc al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 53 -qadisiyah journal for engineering sciences . all rights reserved (a) with no load (b) with load =10% from step input figure 16: output time response of the servo motor with uncertainty parameter of about 10 % controlled by the pid like it2flc conclusion in this paper, the p/pi/pd/pid like it2flc has been implemented on fpga chip. this proposed controller is designed to control linear and nonlinear models. thellpractical results showed that the unit step responsellof nonlinear model controlledllby the proposed controllerllafter changing the uncertainty parameters with 10% was close to response of the same model before this changing. it can be used with industrial, home, medical andllmilitary applications. thellend user can select sampling time, the structure ofllthe controller, number of membershipslland tune the gainsllonly. references 1. m. y. hassan and w. f. sharif.” design of fpga based pid like fuzzy controller for industrial applications”, …0international journal of computer science, 2007. 2. y. maldonado. o. castillo and p. melin. “optimal design of type-2 fuzzy controllers with a .multiple objective …..genetic algorithm for fpga implementation”, fuzzy information .processing society (nafips), 2011. 3. a. s. mani and t. barjeev "design and implementation of fuzzy controller on fpga".international journal 000intelligent systems and application, pp. 35-42. september 2012. 4. m. k. panda, g. n. pillai and v. kumar, "design of an interval type2 fuzzy logic controller for automatic …...voltage regulator system", electric.power component and system .vol.40, 219–235, 2012. 5. l. j. jun . h. h. hsuan. c. p. hwai. “evaluation of an fpga-based fuzzy logic control of feed-.water for abwr …..under automatic power regulating.” progress in nuclear energy. vol. 79. pp..22–31. 2015. 6. m. d. schrieber and m. biglarbegian, "hardware implementation and.performance .comparison of interval type-2 …..fuzzy logic controllers for real.time .applications", application .soft computing, vol. 32, pp. 175–188,.2015. http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=5743636 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 54 -qadisiyah journal for engineering sciences . all rights reserved 7. h. li, x. sun, p. shi and h.k. lam, "control design of interval type2.fuzzy systems with actuator fault: sampled data control approach",.information .science, vol. 302, pp. 1–13, 2015. 8. j. m. mendel. r. i. john and f. liu. "interval type-2 fuzzy logic systems made simple".ieee transactions on …...fuzzy systems. vol. 14. no. 6. december 2006. 9. n. n. karnik. j. m. mendel. and q. liang. “type-2 fuzzy logic systems.” ieee trans. on fuzzy systems. vol. 7. pp. …..643–658. 1999. 10. d. wu and w. w. tan. “genetic learning and performance evaluation of type-2 fuzzy logic controllers.” engineering ……applications of artificial intelligence. vol. 19, no. 8, pp. 829–841, 2006. 12. donald g. bailey, "design for embedded image processing on…fpgas" , .new zealand, john wiley ……..& sons , 2011. 13. w. xie. "sliding mode observer based adaptive control for servo actuator with friction."ieee transaction on ……industrial electronics. vol. 54. no. 3. pp. 1517-1527. june 2007. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٢ numerical analysis of velocity profile and separation zone in open channel junctions waqid hameed al-mussawi college of engineering karballa university abstract the junction open channel flow is encountered in many hydraulic engineering such as irrigation ditches, wastewater treatment facilities and fish passage conveyance structures. the flow behavior at junction becomes very complex because of the interaction between the branch and main channel, that’s cause many complex problems such as local sedimentary, channel scour and sidewall erosion and others. this paper provides detail application of numerical solution (finite volume) by fluent-2d software in simulation of 90º open channel junction flows. numerical simulations undertaken in present two dimensional work use standard k-ε turbulence model. comparisons have been made between numerical results and measured experimental velocities of weber et al. (2001), good agreement between the model predictions and experimental measurements have been obtained. the model is then applied to investigate the dimensions of separation zone. the simulation results show that separation zone size increases as the discharge ratio of the upstream main channel to the downstream channel decreases. l�� -������vال0او-%��� ا����� ا�����! ا���دي ���� �i(�yت ا��%)ات ا��� وا���i �e ا��)�)ي آ��� ا�,%��� .�-�� آ� ء ا�� $� �c3رو���ا�?� ��3ث آ��8ًا %� ا�?�3#+� eا��#�ات ا�� � i��a ا�me�ت ،ان أ� ��ء ا��u��ن %u���a lات ا��ي وو���#k �آ�� % ا.وa#<.ت /��� �aور ا:���ك %� ا�*3ود��#a � ��ء �=�3��a bًا 3gا وذ�t�*( q ا� 3ا� )�i��a h ا��#�ة ان ���ك ا��u��ن %�, �*�lا��#�ة ا�� i��a pa � �e8 +،ا�a ا��<�آ ا����3ة ha 3�3ا�� c>� ا����)��ت 3وه6ا p�u/و ��f�ا�� t��� وث �vه�ة ا� ���#�ة و��kه� ����u3ران ا�uا��#�ة و/.آ ا� .و/��� ���=e/ @��� ا��u�م ا���3دةان ه6ا ا���$ ��3م /����� ا:)��د )l�#) ��� ا��3ديfinite volume( na���( � )�ا� (fluent) و)rاو�+� eء ا��#�ات ا���� أ���#a � standard) أ)*��ن ا������ -ا� �3م a�د� آ� .90º ����آ�ة ا��u��ن % k-ε)ن���u�8 ا��/ ���ب %mن ا�����u�� .ت ا�و����a nl� � /��a 7ر���� ا��)�3� ha ا���د� ا��3دي pa ا�# �nl ا��� �* ا����� ha weber et al.(2001) ، ��� -7 .و��3 اv?�ت ا����ر� 3�g :��kًا )�h ا�# �nl ا���*�) ha ا���د� وا�# �nl ا��� ا:��rال ��#a أ)��د h ي�� �� �f��ا�� �3م ا���د� أv?�ت �3و��، (separation zone)ا���#a 7u+ ا����آ�ة أن nl� ��ة ا��#�ةra �% ��cا� i��= ا�� ا��*�l3م ا��#�ة ا���a i��=/ �*� 0�k داد آ���r� الr��:ا . introduction the junction open channel flows are incredibly complex and interest in environmental and hydraulic engineering. it occurs in many hydraulic structures such as wastewater treatment facilities, irrigation ditch, fish passage conveyance structures and natural river channels. since we are facing different hydraulic conditions to cause changes in channel alignment, combining of two flows accompanies many complex problems such as local sedimentary, channel scour and sidewall al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٣ erosion and others. some of distinctive characteristics of a junction flow in an open channel are illustrated in fig.1.a zone of separation immediately downstream of the junction branch channel, a contracted flow region in the main channel due to the separation zone, a stagnation point immediately upstream of the junction, a shear plane developed between the two combining flow, and an increase in depth from the downstream channel to the upstream contributing channels. the zone of separation results due to the momentum of the lateral branch flow causing the main flow to detach at the downstream corner of the junction. due to a number of important flow phenomena involved, many studies have been conducted to seek the detailed hydrodynamics characteristic of complex junction flow. taylor (1944) conducted the first detailed experimental study in an open channel and proposed a graphical solution, which included a trail-and -error procedure. best and reid (1984) show that a well-defined relationship between the dimensions of the separation which form immediately downstream of the junction and the ratio of discharge from the tributary to the total discharge.weerakoon et al. (1991) examined the three-dimensional flow structure at a junction by means of experimental measurements and a computational model incorporating the k-ε turbulence closure scheme. weber et al. (2001) performed an extensive experimental stud of combining flows in 90º open channel for the purpose of providing a very broad data set comprising three velocity components, turbulence stresses, and water surface mappings. huang et al. (2002) provided a comprehensive numerical study of combining flows in open channel junction using the 3d turbulence model and validated the model by using the experimental data. mao and wu rong (2003) provided a numerical simulation of open channel flow in 90º combining junction using hanjalic-launder (h-l) modification model to analyze the relative importance of various factors and was compared with laboratory measurements. a numerical model using finite-element methods was presented by chong (2006), analysis the open channel junction and a simple comparison with experimental data for velocity profiles were done. pirzadeh and shamloo (2007) provide application of fluent -2d&3d software in simulation of lateral intake flows. comparisons have been made between numerical results and measured experimental velocities for a lateral intake. comparisons indicate that the 2d simulating captures most experimental trends with reasonable agreement and 3d simulating results have also good accuracy. shamloo and pirzadeh (2007) provide the application of fluent-2d software in simulation of lateral intake flows, used standard k-ε turbulence and rsm turbulent models. in the current study an attempt has been made to model fluid flow through open channel t-junction using fluent software and numerical 2-d results for velocity profiles and the dimensions of separation zones with different discharge ratios. aim of study the river confluence, which can be defined as a junction of two or more streams, is a frequently found element along a river path. it facilitates to join all streams from many sources over the basin and allows draining them in the form of a river. the river bank erosion and the plunge of the bank due to the lateral flow are critical due to the bank safety. this is well evidenced by the failure of levees at the confluences of many rivers during the floods which resulted serious damages in many countries. in the design of flood-control channels and fish passage conveyance structures, one of the more important hydraulic problems is the analysis of the flow conditions at open channel junctions. it has recently become more popular to improve the design process using the result from a numerical model study. applying computational fluid dynamics (cfd) in this field of engineering can improve the final design and accelerate the design process. also it is importance lies in the fact that the analysis of the junctions is of considerable use to engineers engaged on the design of irrigation systems, drainage systems, channel in sewerage treatment works and other similar projects. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٤ the objective of the present study is the use of 2-d numerical model to predict the velocity profile and dimension of separation zone in the combining flows of open channel junction. experimental data velocity profiles obtained from the current numerical model were compared with laboratory experiment results performed by weber et al. (2001); in their experimental set-up, a sharpedged,90ºcombining flow flume with horizontal slop as show in (fig. 2).the upstream main channel, branch channel, and combined tail water flow are denoted as qm,qb and qt, respectively. the flow ratio q* is defined as the upstream main channel flow qm to the constant total flow qt which is equal to 0.170m 3 /s.the flow conditions tested are listed in table1.only q* equal to 0.420 and 0.750 were selected for model simulation. weber et al. (2001) presented the results by using normalized distance. all distance were normalized by the channel width, w =0.91m.the non-dimensionalized coordinates are called x*, y*, and z* for x/w, y/w, and z/w, respectively. numerical model description fluent is the cfd solver for choice for complex flow ranging from incompressible (transonic) to highly compressible (supersonic and hypersonic) flows. providing multiple choices of solver option, combined with a convergence-enhancing multi-grid method, fluent delivers optimum solution efficiency and accuracy for a wide range of speed regimes. the wealth of physical models in fluent allows you to accurately predict laminar and turbulent flows, various modes of heat transfer, chemical reactions, multiphase flows, and other phenomena with complete mesh flexibility and solutionbased mesh adoption (fluent user guide 2003). fluent solves governing equations sequentially using the control volume method. the governing equations are integrated over each control volume to construct discrete algebraic equations for dependent variables. these discrete equations are linearized using an implicit method. as the governing equations are nonlinear and coupled, iterations are needed to achieve a converged solution. conservative form of the navier-stokes equations using the finite volume method on structured orthogonal, cartesian coordinate’s grid system. turbulent flows can be simulated in fluent using the standard k-ε, les, rng, or the reynoldsstress (rsm) closure schemes. the model optimizes computational efficiency by allowing the user to choose between various spatial (second-order upwind, third-order, quick) discritization scheme. in the present study used second order upwind discritization scheme for momentum, turbulent kinetic energy and turbulent dissipation rate; used body force weighted discritization scheme for pressure and simple algorithm for pressure-velocity coupling method. mathematical modeling 1governing equations the governing equations of fluid flow in rivers and channels are generally based on threedimensional reynoldes averaged equations for incompressible free surface unsteady turbulent flows as follows (fluent user guide 2003):                 ∂ ∂ + ∂ ∂ +      +− ∂ ∂ = ∂ ∂ + ∂ ∂ i j j i tij jj i j i x u x u vkp xx u u t u δ ρ 3 21 (1) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٥ where: ui=velocity in the xi direction; t = time; ρ=density of flow; p=total pressure; k=turbulently kinetic energy; δij=kronecker delta; vt=turbulent viscosity; and i, j=1, 2, 3. there are basically five terms: a transient term and a convective term on the left side of the equation. on the right side of the equation there is a pressure/kinetic term, a diffusive term and a stress term. in the current study, it is assumed that the density of water is constant through the computational domain. the governing differential equations of mass and momentum balance for unsteady free surface flow can be expressed as (rodi, 1993): (2) ixi ij i j i ug x p x u u t u 21 ∇++ ∂ ∂ −= ∂ ∂ + ∂ ∂ ν ρ (3) where v is the molecular viscosity; gxi is the gravitational acceleration in the xi direction. as in the current study, only the steady state condition has been considered, therefore equation (2) to (3) incorporate appropriate initial and boundary conditions deployed to achieve equilibrium conditions. 2the standard k-ε model turbulent stresses in reynolds-averaged equations can be closed using any of several exiting turbulence models. no single turbulence model is accepted universally for solving all closes of problems but each model has certain advantages over the others depending on the type and the nature of the flow field to be simulated and the desired accuracy of results (neary and odgaard, 1993). in the standard k-ε turbulence model, reynolds stresses in the reynolds-average navier –stokes equations are modeled by the product of an isotropic eddy viscosity and the local rate of strain. the eddy viscosity is obtained from the product of local turbulence length and velocity scales. the turbulence velocity scale is represented by k 1/2 , where k is the turbulence kinetic energy per unit volume, and the turbulence length scale is determined from ε, the turbulence kinetic energy dissipation rate per unit volume. both k and ε are derived from transport equations, which are closed by using a number of semi-empirical procedures in which standard constants are employed (rodi, 1984). the simplest and most widely used two-equation turbulence model is the k-ε model that solves two separate equations to allow the turbulent kinetic energy and dissipation rate to be independently determined. the turbulence kinetic energy, k, is modeled as: ε σ −+         ∂ ∂ ∂ ∂ = ∂ ∂ + ∂ ∂ k jk t jj j p x kv xx k u t k (4) where pk is given by:         ∂ ∂ + ∂ ∂ ∂ ∂ = j i i j i j tk x u x u x u vp (5) (6) 2ε µ k cv t = 0= ∂ ∂ i i x u al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٦ the dissipation of k is denoted ε, and modeled as: k cp k c x v xx u t k j t jj j 2 21 εεε σ εε εε ε ++         ∂ ∂ ∂ ∂ = ∂ ∂ + ∂ ∂ (7) the constants in the k-ε model have the following values: cµ=0.09, cε1=1.44, cε2=1.92, σk=1.0 and σε=1.30 3boundary and initial conditions appropriate conditions must be specified at domain boundaries depending on the nature of the flow. in simulation performed in the present study, velocity inlet boundary condition used for two inlets (main cannel and branch) at all of runs. outflow boundary condition used for outlet at all of runs. the length of the main and branch channels were chosen properly with experimental dimensions (fig.2). the no-slip boundary condition is specified to set the velocity to be zero at the solid boundaries and assumed to be smooth. in simulation performed in the first case of present study, velocity inlet boundary condition is specified, and calculated depend on the discharge ratio. in this case two discharge ratios q*=qm/qt equal to 0.420 and 0.750 were used corresponding to the weber et al. experiments. in the second case, discharge ratios q*=qm/qt equal to 0.083, 0.250, 0.420, 0.583, 0.750 and 0.920 were used. a finite volume approach is used for the solution of the governing equations. second order upwind scheme is selected to discretize the governing equations. simple algorithm is used for pressurevelocity coupling. it is also important to establish that grid independent results have been obtained. the grid structure must be fine enough especially near the wall boundaries and the junction, which is the region of rapid variation. various flow computational trials have been carried out with different number of grids in x and y directions. it was found that results are independent of grid size, if at least 5450 nodes are used. computational mesh is shown in fig.3. results and discussions 1velocity field the velocity profiles of turbulent junction open channel flow are of great interest to engineers, particularly in determining the surface resistance to flow which has practical consequences, such as in the estimation of soil erosion and sediment transport in alluvial channels. in the first case of this paper numerical investigations are performed for evolution of the ability of an available 2d flow solver to cop with the fully turbulent flow in a t-junction. in the figures (4) to (13) and (14) to (23) results of the numerical model are compared with experimental xvelocity profiles in the main channel at 10 non-dimensional locations at x-direction for discharge ratios (q*=0.750 and 0.420) respectively. the velocities are non-dimensionalized with respect to the average downstream, tail water velocity (0.628 m/s). from these figures, it can be concluded that results generally have reasonable agreement with measured ones, but at some sections the computed results do not agree very well with those measured, which might be partly due to the threedimensional effects. further, due to limitation of two-dimensional numerical model the vertical acceleration is neglected in the current 2dstudy. however, both results show the increasing of velocity at outer wall region downstream of the junction. statistical analysis of the results obtained was ,also, applied by using chi square test (goodness-offit tests) to ensure the previous conclusion. the chi-square test is the more interesting statistical tests in the engineering field so that it can be used in this analysis. the equation of chi-square known as the following(william,1980): (8) ( ) ∑ = − = r j j jj fe fefo 1 2χ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٧ where: j fo :observed values, j fe :expected values and r: number of rows. the application of results the chi-square equation on the velocities data using level of significance ( 05.0====α and 1.0====α ) is shown in table (2). it is shown from these analysis, that the chi-square values ( 2 χ ) from equation for all cases less than the chi-square values ( 2 α χ ) tabulated for level of significance ( 05.0====α and 1.0====α ).from this result we can conclude that all these computed velocities are approximated from the experimental results . it is found that the fluent is an effective tool for predicting flow pattern of the combining flows in open channel junction. 2dimension of separation zone in the downstream main channel in the second step at this study, numerical approaches were used to understand flow structure and separation zone at the combining flows in open channel junction. it was found that the size of separation zone is very much dependent on the discharge ratio. the result showed that the separation zone (recirculation) was observed immediately downstream of the junction due to deflection from outer wall. figure (24) shows 2d streamlines plots for discharge ratios (q*=0.083, 0.250, 0.420, 0.583, 0.750 and 0.920). these figures elucidate the structure of the combining streams and the zone of flow separation in downstream main channel. the momentum of the lateral branch flow caused the main flow to detach at the downstream corner of the junction. this is more significant for lower (q*) flow condition. as a result, the water depth raised up at the upstream of main channel. by comparing these figures, it is seen that an increase in discharge ratio causes shortening and narrowing of the separation zone. moreover, the models results show that higher (q*) will take shorter distance downstream from the junction to reach uniform flow condition again. figures (25) and (26) present the predicted variation of non-dimensional maximum width (sw) and length (sl) of separation zone in the main channel respectively, for different discharge ratios. results indicate that both length and width of the separation zone decrease with increasing discharge ratio. separation zone reduces the effective width of the channel. separation zone can be defined as the area of reduced pressure and re-circulating fluid with low velocities; therefore it has a strong sediment deposition potential in which sediment particles enter the main channel. it can be seen that for a lower discharge ratio, more than 25% of the downstream main channel width is occupied by the recirculation zone. fig.27. shows that the contraction coefficient cc, (cc=effective width of d/s main channel (wsw)/width of main channel (w)), increases linearly as discharge ratio increases. this indicates that a smaller branch discharge qb results in a small effective width in the recirculation region of the d/s main channel. the ratio of maximum width (sw) and length (sl) of the separation zone shown in fig.28.this ratio increased in general as discharge ratio increased. the values of (sw/sl) range closely around mean value of (0.18); this value was very closely from the mean value (0.19) which calculated by best and reid (1984). summary and conclusions in this study the velocity components and dimensions of separation zone at the downstream main channel for combining flows in a 90°, sharp-edged, rectangular open channel junction formed by channels of equal width are obtained on the basis of numerical studies. it was found the size of separation zone is very much dependent on the discharge ratio. in all cases, the results showed an increase in discharge ratio causes shorting and narrowing of the separation zone. the numerical simulation models results show that higher discharge ratio will take shorter distance downstream from the junction to reach uniform flow condition again. so, the contraction coefficient increases with the increase in the discharge ratio. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٨ references best, j. l. and reid, i. (1984), "separation zone at open channel junctions." journal of hydraulic engineering. asce, vol. 110, no. 11, pp.1588-1594. chong, n.b. (2006), "numerical simulation of supercritical flow in open channel.", m.s.c thesis, university technology malaysia. fluent user’s guide manual-version 6.1., fluent incorporated, n.h., 2003. huang, j., weber, l.j., lai, y.g. (2002), "three dimensional numerical study of flows in open channel junctions.", journal of hydraulic engineering. asce, vol.128, no.3, pp.268-280. mao, z. and rong, w. (2003), "numerical simulation of open-channel flow in 90-degree combining junction.", journal of tsinchua science and technology, vol.8, no.6, pp.713-718. neary, v.s. and odgaard, a.j. (1993), "three dimensional flow structure at open-channel diversions. ", journal of hydraulic engineering. asce, vol.119, no.11, pp.12231230. pirzadeh, b. and shamloo, h. (2007), "numerical investigation of velocity field in dividing open channel flow." proceedings of the 12th wseas international conference on applied mathematics, cairo, egypt, desember29-31, 2007, pp.194-198. rodi, w. (1984), " turbulence models and their applications in hydraulics a state of the art review", iahr, the netherlands. rodi, w. (1993), "turbulence models and their application in hydraulics.", iahr, delft, the netherlands. shamloo, h. and pirzadeh, b. (2007), "investigation of characteristics of separation zones in tjunctions.", proceedings of the 12th wseas international conference on applied mathematics, cairo, egypt, desember29-31, 2007,pp.189-193. taylor, e.h. (1944), "flow characteristics at rectangular open-channel junctions. ", transactions, asce, vol.109, pp. 893–902. weber, l. j., schumate, e. d., and mawer, n. (2001), " experiments on flow at a 90◦ open-channel junction.", journal of hydraulic engineering, asce, vol. 127, no. 5, pp. 340-350. weerakoon, s. b., kawahara, y. and tamai, n. (1991), "three-dimensional flow structure in channel confluences of rectangular section.", international association for hydraulic research, a, pp.373-380. william, l. hays, (1980)," statistics", third edition, p.539. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٦٩ table1: flows tested qm(m 3 /s) qb(m 3 /s) qt(m 3 /s) q*=qm/qt 0.014 0.156 0.170 0.083 0.042 0.127 0.170 0.250 0.071 0.099 0.170 0.420 0.099 0.071 0.170 0.583 0.127 0.042 0.170 0.750 0.156 0.014 0.170 0.920 table2: chi-square test figure1. flow characteristics in open channel junction ( 2 α χ ) tabulated use 1.0====α ( 2 α χ ) tabulated use 05.0====α ( 2 χ ) calculated correlation coefficient x* q* 13.361 15.507 0.181 0.926 -1 13.361 15.507 0.176 0.983 -2 13.361 15.507 1.352 0.995 -3 10.644 12.591 0.231 0.969 -4 10.644 12.591 0.051 0.989 -5 0.42 13.361 15.507 0.566 0.959 -1 13.361 15.507 0.323 0.995 -2 13.361 15.507 0.214 0.987 -3 10.644 12.591 0.110 0.994 -4 10.644 12.591 0.125 0.984 -5 0.75 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٠ x y figure 2.plan view of test facility 90º junction figure 3.computational geometry and grid. x* y* al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧١ fig.٨.x-velocity profile in the main channel(x*=-2.67) q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study fig.4.x-velocity profile in the main channel(x*=-6) fig.٥.x-velocity profile in the main channel(x*=-5) fig.٦.x-velocity profile in the main channel(x*=-4) fig.٧.x-velocity profile in the main channel(x*=-3) fig.12.x-velocity profile in the main channel(x*=-1.34) fig.11.x-velocity profile in the main channel(x*=-1.67) fig.10.x-velocity profile in the main channel(x*=-2) fig.9.x-velocity profile in the main channel(x*=-2.34) q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 y* weber et al. (2001) present study q*=0.750 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 y* weber et al. (2001) present study fig.13.x-velocity profile in the main channel(x*=-1) q*=0.750 0 0.2 0.4 0.6 0.8 1 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٢ fig.18.x-velocity profile in the main channel (x*=-2.67) fig.17.x-velocity profile in the main channel (x*=-3) fig.16.x-velocity profile in the main channel (x*=-4) q*=0.420 0 0.2 0.4 0.6 0.8 1 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study fig.14.x-velocity profile in the main channel (x*=-6) fig.15.x-velocity profile in the main channel (x*=-5) q*=0.420 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 y* weber et al. (2001) present study fig.23.x-velocity profile in the main channel (x*=-1) fig.22.x-velocity profile in the main channel (x*=-1.34) fig.21.x-velocity profile in the main channel (x*=-1.67) fig.20.x-velocity profile in the main channel (x*=-2) fig.19.x-velocity profile in the main channel (x*=-2.34) q*=0.420 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -4 -3 -2 -1 0 1 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 y* weber et al. (2001) present study q*=0.420 0 0.2 0.4 0.6 0.8 1 -2.5 -2 -1.5 -1 -0.5 0 y* weber et al. (2001) present study al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٣ q*=0.92 -1 -0.5 0 0.5 1 -7 -6 -5 -4 -3 -2 -1 0 1 2 x*=x/w y *= y /w q*=0.083 q*=0.92 -1 -0.5 0 0.5 1 -7 -6 -5 -4 -3 -2 -1 0 1 2 x*=x/w y *= y /w q*=0.25 q*=0.92 -1 -0.5 0 0.5 1 -7 -6 -5 -4 -3 -2 -1 0 1 2 x*=x/w y *= y /w q*=0.42 q*=0.92 -1 -0.5 0 0.5 1 -7 -6 -5 -4 -3 -2 -1 0 1 2 x*=x/w y *= y /w q*=0.58 q*=0.92 -1 -0.5 0 0.5 1 -7 -6 -5 -4 -3 -2 -1 0 1 2 x*=x/w y *= y /w q*=0.75 y *= y /w q*=0.92 -1 -0.5 0 0.5 1 -7 -6 -5 -4 -3 -2 -1 0 1 2 x*=x/w y *= y /w q*=0.92 y *= y /w figure 24. 2d-streamlines plot for different discharge ratios (q*). y *= y /w 11 y * = y /w y * = y /w y * = y /w y * = y /w y * = y /w y * = y /w 273 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٧٤ 0 0.1 0.2 0.3 0.4 0 0.2 0.4 0.6 0.8 1 q* s w /w numerical results(fluent) 0 0.4 0.8 1.2 1.6 2 2.4 0 0.2 0.4 0.6 0.8 1 q* s l/ w numerical results(fluent) fig.25.dimensionless width separation zone with discharge ratio fig.26.dimensionless length separation zone with discharge ratio 0 0.05 0.1 0.15 0.2 0.25 0 0.2 0.4 0.6 0.8 1 q* s w /s l numerical results(fluent) 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 0 0.2 0.4 0.6 0.8 1 q* c c numerical results(fluent) fig.27.contraction coefficient in d/s main channel with discharge ratio fig.28.the ratio of dimensionless width/length of separation zone with discharge ratio article al-qadisiyah journal for engineering sciences 13 (2020) 274–283 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: s.ali1101@coeng.uobaghdad.edu.iq( sahar h. ali ) https://doi.org/10.30772/qjes.v13i4.681 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. improving the moisture damage resistance of hma by using ceramic fiber and hydrated lime sahar hussein ali a* , mohammed qadir ismael a a university of baghdad / civil engineering department, baghdad, iraq a r t i c l e i n f o article history: received 19 august 2020 received in revised form 25 september 2020 accepted 25 september 2020 keywords: moisture susceptibility ceramic fibers hydrated lime tensile strength ratio index of retained strength a b s t r a c t the moisture damage is considered as one of the main challenge for the experts in the field of asphalt pavement design. the aims of the present study is to modify moisture resistance of the asphalt concrete by utilizing ceramic fibers as a type of reinforcement incorporated with hydrated lime. for this purpose, a penetration grade of the asphalt cement (40-50) was utilized as a binder with an aggregate of the maximum nominal size of 12.5mm and mineral filler limestone dust. a series of specimens has been fabricated by utilizing 0.50, 1.0, 1.5, and 2.0 percentages from the weight of total mixture of ceramic fibers. for each of these contents, another subsequent group of specimens with hydrated lime with 0.0, 1.0, 1.5, and 2.0 percentages from the total weight of aggregate were molded. for the addition of ceramic fiber and hydrated lime to the mixtures, the dry method for ceramic fiber was adopted. while for the hydrated lime, the saturated surface dry method was adopted. the results of this study have shown that the addition of 1% ceramic fiber from the total weight of the asphalt mixture with 1.5% hydrated lime recorded the highest levels of increase. furthermore, the outputs of the tests used in this study have shown that the use of ceramic fibers resulted in an increase in the value of tensile strength ratio (tsr) and in the index of retained strength (irs) compared with the control mixture. maximum values for tsr were achieved at 1% ceramic fibers with 1.5 % hydrated lime. maximum values for tsr were achieved at 1% ceramic fibers with 1.5 % hydrated lime. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction moisture damage is one of the main reasons for the early failure in the asphalt concrete mixtures. a correct assessment of the moisture susceptibility is necessary to prevent the deterioration of the field mixtures adriana et al. [1]. the moisture damage as distresses that influence the community in various ways can be considered. economically, the maintenance and rehabilitation of the damaged pavements that are resulted from the moisture damage cost millions of dollars [2 –3]. besides, susceptibility due to moisture is a major concern in asphalt pavements; it can be considered as a deterioration within the mechanical property of the asphalt because of the impact of moisture or water that causes severe distresses. the asphalt mixture's resistance to the moisture damage is highly critical for its long-term performance. if the asphalt mixture is susceptible to the moisture damage, it could, in the end, fail in any of the http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 275 failure modes, i.e. rutting, fatigue, thermal cracking, or ravelling sebaaly et al. [4]. moisture damage in asphalt pavement can lead to several distresses inside asphalt structures such as bleeding, cracking, rutting, ravelling and localized failures which are similar to distress resulting from some other factors such as materials, design, and construction. it is then necessary to differentiate between distresses resulting from moisture or those resulting from the effect of other factors and to consider this as the first step is in selecting the proper solution hicks et al. [5]. because of the growing cost of repairing and renewing damaged pavements, extended studies have been carried out to the resistance against damages and to the growing of their service-life arabani et al. [6]. many studies have inspected the use of fibre to get better the performance of hma: some focused on specific performance concerning water effects, environment, and temperature xu et al. [7]. at the same time, other experiments were conducted to highlight the mechanical performance of hma, e.g. fatigue, rutting, and stiffness moreno-navarro et al. [8]. different kinds of the modifier fibres like cellulose, polyester, glass, and mineral fibres are widely used into dissimilar types of asphalt mixtures wan et al. [9]. the influence of reinforcement of the fiber is improved by various means of improving its quantity into a definite value, relying on the kind and length of the fibres wu et al. [10]. ceramic fiber has an extensive application value in everyday life and it forms a whole industry as a substance for heat insulation. the main chemical composition of the ceramic fiber is al2o3 and sio2. at the same time, depending on the various purposes, some other chemical substances are added to it to improve its properties. the ceramic fiber diameter ranges from 2 to 5 µm, and the length is nearly 20 mm. its advantages involve being of lightweight, having thermal insulation, no toxicity, resistance to mechanical vibration, and is of low cost compared with other fibers. ceramic fiber can improve the rendition of the asphalt mixtures because it has a high stability to temperature and chemical changes, appropriate flexibility, and adequate shock resistance. the reinforcing properties of these fibers along with their low deleterious influences and easy-accessibility can make them suitable additives to improve the characteristics of the binder and the asphalt mixture wan et al. [9]. anti-stripping agents are categorized into two sets: the first includes those added to the asphalt binder which are usually chemical liquids called "liquid anti stripping agents" while the second set includes those attached directly to the aggregate like fly ash, lime, portland cement, flue dust, polymers, cement klein, and numerous others, epps et al. [11]. the main goal of adding anti-stripping agents is to reduce the moisture sensitivity of the asphalt mixtures by improving the bond between the asphalt binder and the aggregate. lime has been widely utilized as both a filler and additive to resist moisture in asphalt mixtures ismael et al. [12]. three major forms of lime are used with asphalt mixtures according to hunter et al. [13]; hydrated lime (ca(oh)2), quicklime (cao), and dolomitic lime (cao.mgo). the increase in road traffic with inadequate and the repeated with less the maintenance exacerbated the deterioration of asphalt pavements, during the past 20 years in iraq. the major structural distress that led to a reduction in the serviceability of asphalt pavements are cracking and rutting. therefore, different types of additives and modifiers are utilized in asphalt to decrease the distresses effect hunter et al. [14]. the objective of that research is to study the application of one of the most widely utilized fibres in the insulation manufacture in the asphalt mixtures. the significance of the present study is to use ceramic fibre as suitable and cost-effective additives to excess the service-life of the asphalt pavements, which could promote more types of researches in the future. in this study, hydrated lime was used as anti-stripping with the ceramic fibres as reinforcement fibres for the asphalt mixture. 2. experimental work 2.1. materials the materials utilized in this research are locally obtainable and are now used in road constructions in iraq. ceramic fiber and hydrated lime are available in the local market. all materials were obtained from commercial sources without trying to get private products. therefore, this research investigates the use of the ceramic fibers as reinforcement fibers for improving their resistance to the moisture damage in the asphalt mixtures. 2.1.1. asphalt cement (ac) one kind of ac with a penetration grade of (40-50) and produced by al–daurah refinery was used here. the physical properties of asphalt cement utilized in this study are shown in table 1. the test results were to meet the state commission of roads and bridge (scrb) [15] specifications. 2.1.2. coarse aggregate the crushed coarse aggregate of about between the sieve size (19mm) and sieve (4.75 mm) has been gained from the al-nibaee quarry; it accords to the (scrb) [15] specifications. specifications. the physical property of the coarse aggregate is shown in table 2. 2.1.3. fine aggregate the crushed fine aggregate of about between the sieve size (4.75 mm) and sieve size (0.075 mm) has been gained from the same source of coarse aggregate. it consists of tough, hard, grains, free of the injurious amount of clay, loam, or other harmful substances. the physical property of the fine aggregate is shown in table 3. 2.1.4. mineral filler the substance passage from sieve size (0.075mm) is called the mineral filler. it must be dry and free of the accumulation of accurate particles. the filler material used in making asphalt mixture is the limestone dust because of its availability and comparatively low cost. the physical property of the mineral filler is shown in table 4. nomenclature ac asphalt cement, % ssd saturated surface dry astm american society for testing and material t the specimen thickness, mm d diameter of specimen, mm tsr the tensile strength ratio, % hma hot mix asphalt irs index of retained strength, % its indirect tensile strength, kpa p ultimate load failure, n scrb state commission of roads and bridge 276 sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 2.2 combination of aggregate gradations a manual sieving for the coarse and fine aggregate was used to classify it into sets according to size. in this study, one kind of gradation was utilized, (12.5mm) nominal maximum size. then, the combination percent for type iiia wearing coarse was selected to meet the job mix formula specified by the (scrb) [15]. the aggregate gradation is shown in table 5 and fig. 1. table 1: physical properties of ac (40-50 ). tests units results scrb 2003 specification limits [15] astm designation [16] penetration (25 °c, 100 gm., 5 sec) 1/10 mm 47 40 – 50 d-5 ductility (25 ° c, 5 cm/min) cm 135 ≥ 100 d-113 kinematics viscosity, @ 135° c cst 405 ─ d-2170 softening point (ring & ball) °c 50 ─ d-36 flash point (cleveland open cup ) °c 270 232 min. d-92 specific gravity at 25 °c ─ 1.04 ─ d-70 after thin –film oven test astm d 1754 retained penetration of residue (25°c, 100 gm. , 5 sec ) % 60 55(min) d 5 ductility at 25 ° c, 5 cm/min cm 82 >25 d-113 table 2 : physical properties of coarse aggregate. property astm designation [16] results scrb specification [15] bulk specific gravity c-127 2.579 --- apparent specific gravity c-127 2.601 --- percent water absorption c-127 0.54 --- percent wear (los angeles abrasion) c-131 15.79 30 max table 3: the physical properties for the fine aggregate. properties astm designation [16] result scrb 2003 specifications [15] bulk specific gravity c-128 2.61 -- apparent specific gravity c-128 2.632 -- percent water absorption c-128 0.952 -- table. 4: physical properties of filler (limestone dust). property result % passing sieve n0.200 95 specific gravity 2.71 table.5 : gradation of combined aggregate for wearing course ( type iiia ). sieve size sieve size (mm) specification passing range (%) selection gradation ¾ʺ 19.0 100 100 ½ʺ 12.5 90-100 95 ⅜ʺ 9.5 76-90 83 no.4 4.75 44-74 59 no. 8 2.36 28-58 43 no.50 0.300 5-21 13 n0.200 0.075 4-10 7 figure 1: the specification limits and selected gradation for the wearing course scrb [15]. 2.3. additives: to improve the ability of the asphalt mixtures to resist the damaging effect of moisture presence, ceramic fibres and hydrated lime were used in this research, with different percentages for each additive. 2.3.1. ceramic fibers 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 % p a ss in g sieve size opening , mm selection gradation specification uper limit specification lower limit sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 277 the aluminium silicate fibres are formed by melting and blowing molten kaolin with excessive content of the alumina material, or more popular, the materials to be ceramic fibres arabani et al. [6]. the use of ceramic fibres as a reinforcement of asphalt concrete is limited in iraq. therefore, it is chosen to be used in this study. it was selected due to its high tensile strength property and high melting point. the characteristics of ceramic fibers are listed in table 6. 2.3.2. hydrated lime hydrated lime is well known as an anti-stripping agent. it has been widely utilized as both a filler and additive to resist moisture in the asphalt mixes. hydrated lime is known to be a promising probable substance for pavements because of its unique chemical, physical, and mechanical characteristics. hydrated lime was used as an anti-stripping additive for hma pavements in this study. the physical property and the chemical composition is shown in table 7 and table 8 respectively. table 6 : the basic properties of the ceramic fibers . table 7: physical properties . property hydrated lime specific gravity 2.44 % passing n0.200 99 table 8: chemical composition of hydrated lime . 2.4. the research methodology for this work, the research methodology consists of four phases. the first phase of the experimental part was represented by bringing the substances of asphalt binder, aggregates, the mineral filler, and ceramic fibres and hydrated lime additives and by testing the physical properties of the materials. the second phase include the preparation of asphalt cement mixtures that will be formed to locate the optimum asphalt content of the control mix, without additives. the third phase was to determine the optimum asphalt content of the mixture specimens with ceramic fibre and hydrated lime based on marshall characteristics. moreover, in the fourth phase, in addition to the volumetric properties, the marshall properties flow and stability values are determined to satisfy the requirement of iraqi specifications. the optimum asphalt contents specified by these tests were 4.9 for the control mixture, and 5.30 for modified mixtures. then to produce mixtures for indirect tensile tests to evaluate (tsr) and compressive strength tests for assessing (irs). 2.5. methods of incorporating additives into the mixture to add ceramic fibre with hydrated lime to the asphalt cement mixture, the dry method for ceramic fibre and the saturated surface dry process for hydrated lime were used. using the saturated surface dry method (ssd) for hydrated lime, water was added at 3% of the weight of the combined aggregate without filler. then, the additives were added and well mixed with; the wet aggregate was left to dry in an oven for two hours at 150 °c. after that, the filler was added to and mixed with asphalt. 2.6. tensile strength ratio test (tsr) the process for preparing and testing the asphalt concrete samples and of measuring the influence of moisture on the tensile strength for the asphalt mixture is covered by the tsr. this test is utilized to evaluate the impact of the humidity on the asphalt mixture. for more information, astm d-4867 [16] provides a full description of this test. the samples in this test were worked out to have the number of blows that give 7±1% the air voids appropriate to the job mix formulation by the trial method by prepared samples free from any additive by made by using the number of blows(45,55,65,75) respectively. the number of blows was 54 to give this percent, as shown in fig. 2 below. after identifying the number of blows, groups of marshall specimens were prepared in six samples where each group is divided into two sets, three samples for every set. the first set was located in a water bath at 25 °c for 30 minutes (specimens unconditioned ), then the its has been calculated for every sample and the its average for the three samples was determined. the second set was located in a vacuum container full of distilled water at 25 °c to remove the air content. after that, the specimens were put in the freezer for 16 hrs. at -18±3 °c. after the freezing cycle, the samples were put at a water bath for 24 hrs. at 60 °c to complete the thawing cycle. it has been extracted and put in another water bath at 25 °c for 1hr, and the its for these specimens conditioned was calculated. properties ceramic fibers type nc1260 appearance white cotton shape morphological structure glass state average length (mm) 2.0 average diameter (𝜇𝑚) 3.0 thermal conductivity 0.03 ) 3density ( kg/m 128 melting point (°c ) 1760 tensile strength ( kpa) 83 the chemical composition (%) 3o2al 52 2+sio3 o2al 95 3o2fe <0.2 2zro / chemical composition percent % cao 56.1 2sio 1.38 mgo 0.13 3o2fe 0.12 3o2al 0.72 3so 0.21 l.o.i 40.65 278 sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 the its calculations are made according to the method shown in astm d-6931-12 [16]. the sample was located in the loading apparatus, and the loading strips have been put parallel and centered onto the perpendicular diametrical level. the length of the loading strips has exceeded the thickness of the specimen. a diametrical load was applied at 50.8mm/min (2in. /min) until the failure of the sample. the samples and the tests are shown in fig. 3. the extreme load which causes that breakdown was registered and the its were calculated according to the following equation: its= 𝟐𝟎𝟎𝟎𝑷𝒖𝒍𝒕 𝝅 𝒕 𝑫 (1) where: its = indirect tensile strength , (kpa) . pult = ultimate applied load required to fail specimen,(n). t = thickness of the sample,(mm). d = diameter of sample , (mm) . after calculation of its for conditioned and unconditioned samples for each set, the tensile strength ratio was calculated as below: tsr = 𝐜𝐨𝐧.𝐈𝐓𝐒 𝐮𝐧𝐜𝐨𝐧.𝐈𝐓𝐒 × 𝟏𝟎𝟎 (2) where : tsr = tensile strength ratio, % . con. its = average its of the moisture – conditioned samples, kpa. uncon. its= average its unconditioned (dry) samples , kpa . the minimum tsr value is ( 80%) according to the astm d-4867-09 [16]. figure 2 : relationship between no. of blows and air voids percent . (a) some of the specimens (b) sample under test . (c) sample after test ( failure). figure 3: tensile strength ratio test 4 5 6 7 8 9 10 40 50 60 70 80 % a ir v o id s no. of blows sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 279 2.7. compressive strength test a compressive strength of a compacted mixture is usually conducted to determine its suitability for use in the pavement under a given load and environmental condition. this test was conducted according to astm d1074 – 02 [16]. the prepared mixture is compacted by using a compressive device. samples of 4 in. height (101.6mm) and diameter of 4 in. (101.6mm) were prepared. the specimens were cooled for 24 hours before being tested for compressive strength at a rate of loading of 5.08 mm/min. then they were placed in a vertical position so that the axial load could be applied to the first surface of the specimen until it fails. compressive strength specimens and tests are shown in fig. 4. (a) cylinder specimens (b) specimen before loading (c) specimen after loading and failure figure 4: compressive strength test. 2.8. index of retained strength test this method covers the measurement of the cohesion loss producing from the impact of water on compressed the asphalt mixtures. a group of six samples prepared for that purpose divided into two groups. three samples for the compressive strength after putting into the air bath with 25 °c for nearly 4 hr. were examined. the three other samples have been put in the water bath with 60 °c for 24 hr. and then transmitted to the water bath, and kept for 2 hours at 25 °c before the compressive strength testing. the irs is calculated in accordance with the astm d-1075-07 [16] specifications, which must be within a minimum of 70% as adopted by scrb [15]. 3. results and discussion 3.1. tensile strength ratio results the dry indirect tensile strength, wet indirect tensile strength, and t.s.r values for the asphalt mixtures containing ceramic fibers with hydrated lime for all percentages are greater than the values of the control mixture. the dry its with 1% ceramic fiber values have been higher than those with 0.5,1.5, and 2 % ceramic fiber. samples containing 1, 1.5, and 2 % hydrated lime (by weighing the total mixtures) with 1% ceramic fiber have higher dry indirect tensile strength values than the mixtures of control. the effect of the ceramic fiber content increases the dry its values because of the increase of tensile modulus of elasticity; this increase is because ceramic fibers with hydrated lime have a much higher strength. the mixture was stiffer into the specimen because the fibers have a random orientation in various directions, strongly connect particles within the matrix, and eventually stop them from moving. furthermore, given that the hydrated lime has a high surface area, the aggregate was plated with enough amount of the asphalt, and as a result, the adhesion force became higher between asphalt and aggregate and prevented the stripping beneath the influence of the moisture. as a result, the value of the tsr increased in a way that indicates the increment in the resistance of moisture of asphalt 280 sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 mixture together with the addition of ceramic fiber and hydrated lime. the effect of ceramic fiber with hydrated lime is shown in table 9 and fig. 5 through 7 respectively. table 9: indirect tensile strength test results. additives additive, % dry its (kpa) wet its (kpa) tsr( %) control mix 0 1243 953 76.71 ceramic fiber with hydrated lime 0.5 cf +1h 1467 1141 77.77 0.5 cf+1.5h 1645 1336 81.22 0.5 cf +2 h 1281 1005 78.49 1 cf +1 h 1489 1180 79.25 1 cf+1.5 h 2170 1917 88.34 1 cf +2 h 1809 1489 82.30 1.5 cf +1 h 1370 1083 79.08 1.5 cf +1.5 h 1526 1222 80.05 1.5 cf +2 h 1415 1117 78.95 2 cf+1 h 1284 994 77.39 2 cf +1.5 h 1348 1061 78.73 2 cf +2 h 1255 968 77.15 figure 5: effect the percentages of ceramic fibers content and hydrated lime content on dry indirect tensile strength . figure 6: effect the percentages of ceramic fibers content and hydrated lime content on wet indirect tensile strength. figure 7: effect of fibers content and hydrated lime content on tensile strength ratio. 3.2. index of retained strength results the irs to evaluates the resistance of the asphalt mixture to the susceptibility of moisture has been utilized. in accordance with the scrb [15], the minimum value of the allowed irs is 70% which has been considered as a measure if the asphalt mixture is susceptible to moisture. the results of the increase in the value of dry compressive strength, wet compressive strength and irs percentage in the asphalt mixture modified with ceramic fiber with hydrated lime is listed in table 10 and fig. 8 through 12. 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 control mix 1 hl 1.5 hl 2hl in d ir e c t t e n si le s tr e n g th ( k p a ) ceramic fiber with hydrated lime, % 2% cf 0.5% cf 1%cf 1.5% cf 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 control mix 1 hl 1.5 hl 2hl in d ir e c t t e n si le s tr e n g th ( k p a ) ceramic fiber with hydrated lime, % 2% cf 0.5% cf 1%cf 1.5% cf 0 10 20 30 40 50 60 70 80 90 100 control mix 1 hl 1.5 hl 2hl t s r , % ceramic fiber with hydrated lime , % tsr% (0.5 % cf ) tsr% (1% cf) tsr% ( 1.5 % cf) tsr% (2% cf ) sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 281 the values for dry compressive strength and wet compressive strength of mixtures that contain ceramic fibers with hydrated lime have been higher than those in the control mixture. the values of the dry and wet compressive strength were higher with 1% ceramic fiber than those with 0.5,1.5, and 2 % ceramic fiber. samples containing 1, 1.5, and 2 % hydrated lime, by weighing the total mixtures, with 1% ceramic fiber have higher values of the dry compressive strength than the mixtures of control. the mixture was stiffer into the specimen because the fibers have a random orientation in various directions, strongly connect particles within the matrix, and eventually stop them from moving. moreover, given that the hydrated lime has a high surface area, the aggregate was plated with enough amount of the asphalt, and as a result, the adhesion force became higher between asphalt and aggregate and prevented the stripping beneath the influence of the moisture. as a result, the value of the irs increased in a way that indicates the increment in the resistance of moisture of asphalt mixture together with the addition of ceramic fiber and hydrated lime. where the addition of ceramic fiber and hydrated lime makes the asphalt mixture of a greater resistance for compression beneath the influence of the moisture. this leads to increasing the irs which in turn leads to increasing the moisture resistance. table 10: results of index of retained strength (irs%) tests. additives additi ves, % dry compressive strength (kpa) wet compressive strength (kpa) irs (%) control mix 0 6858 5052 73.6 7 ceramic fiber with hydrated lime 0.5 cf +1h 7325 5743 78.4 0 0.5 cf +1.5h 8504 7005 82.3 7 0.5 cf +2h 7590 6095 80.3 0 1 cf +1 h 7704 6493 84.2 7 1 cf +1.5 h 9807 8678 88.4 8 1 cf +2 h 7338 6150 83.8 0 1.5 cf +1 h 7046 5898 83.7 1 1 .5cf +1.5 h 7576 6515 86.0 0 1.5 cf +2 h 6931 5779 83.3 8 2 cf +1 h 7064 5889 83.3 7 2cf +1.5 h 7201 6127 85.0 8 2cf +2 h 6927 5647 81.5 2 figure 8: effect of percentages of fiber on the dry and wet compressive strength for (0.5% cf). figure 9: effect of percentages of fiber on the dry and wet compressive strength for (1% cf). 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 control mix 1 hl 1.5 hl 2hl c o m p r e ss iv e s tr e n g th ( k p a ) ceramic fiber with hydrated lime, % wet compressive strength(kpa) dry compressive strength(kpa) 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 control mix 1 hl 1.5 hl 2hl c o m p r e ss iv e s tr e n g th ( k p a ) ceramic fiber with hydrated lime, % wet compressive strength(kpa) dry compressive strength(kpa) 282 sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 figure 10: effect of percentages of fiber on the dry and wet compressive strength for (1.5% cf). figure 11: effect of percentages of fiber on the dry and wet compressive strength for(2%cf). figure 12: effect of fibers content and hydrated lime content on the irs. 4. conclusions according to the specification of substances and test result utilized in the present study, the following points have been concluded: • the addition of ceramic fiber as a reinforcement and the hydrated lime as anti-stripping has led to a reduction in the moisture susceptibility of the asphalt mixture as a result of the excess in tsr values. • the dry its, wet its, and tsr values were higher than the control mixtures for the asphalt mixtures containing ceramic fiber with hydrated lime for all percentages. • the addition of 1% ceramic fiber with1.5% hydrated lime has given the highest tsr which was 86.55 % compared with the control asphalt mixture that was 76.71 %. • the results of the dry compressive strength, wet compressive strength, and irs values were higher than the control mixtures for the asphalt mixtures containing ceramic fiber with hydrated lime for all percentages. • the addition of 1% of ceramic fiber with 1.5% hydrated lime has also recorded the highest irs, which was 88.48 % compared with the control asphalt mixture which has been 73.67 %. acknowledgments thanks and appreciation go to members of the department of civil engineering and the staff of transportation laboratories in the department of civil engineering, university of baghdad for providing research facilities during of work. 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 control mix 1 hl 1.5 hl 2hl c o m p r e ss iv e s tr e n g th ( k p a ) ceramic fiber with hydrated lime, % wet compressive strength(kpa) dry compressive strength(kpa) 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 control mix 1 hl 1.5 hl 2hl c o m p r e ss iv e s tr e n g th ( k p a ) ceramic fiber with hydrated lime, % wet compressive strength(kpa) dry compressive strength(kpa) 0 10 20 30 40 50 60 70 80 90 100 control mix 1 hl 1.5 hl 2hl ir s , % ceramic fiber with hydrated lime, % irs% (2% cf) tsr% (0.5 % cf ) irs% (1% cf) irs% (1.5% cf) sahar hussein ali , mohammed qadir ismael /al-qadisiyah journal for engineering sciences 13 (2020) 274–283 283 references [1] adriana, v.n., fabricio, l. v., josé, p. a., and luis, l. s., evaluating moisture susceptibility of asphalt concrete mixtures through simple performance tests. annual meeting of the transportation research board, 2015. 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[15] state corporation of roads and bridges (scrb), general specification for roads and bridges, section r/9, hot-mix asphalt concrete pavement, in ministry of housing and construction, republic of iraq. 2003. [16] american society for testing and materials (astm), annual book of astm standards, vol. 04.03, in road and paving materials vehicle pavement systems. 2015. https://doi/ article al-qadisiyah journal for engineering sciences 13 (2020) 240–245 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: waleed_eng99@yahoo.com (waleed t.rashid) https://doi.org/10.30772/qjes.v13i3.665 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. effect of operating conditions on the removal of heavy and radioactive elements by reverse osmosis membrane waleed t. rashid a*, israa a. alkadir a, and moayyed g. jalhoom b a production and metallurgy engineering department, university of technology/baghdad b consultantproduction and metallurgy engineering department, university of technology /baghdad a r t i c l e i n f o article history: received 5 july 2020 received in revised form 16 august 2020 accepted 15 september 2020 keywords: heavy and radioactive elements reverse osmosis rejection flux permuted a b s t r a c t the major goal of the presented study is to study the reverse osmosis (ro) characteristics for (cd, u, pb, cu, zn, k, th, and ni) removal from an aqueous solution containing phosphogypsum. this was performed done by examining the impact related to temperature and pressure on the performance regarding the ro membrane in the removal of elements with time. values of temperatures (25, 35, and 45o c) and various pressures such as (2, 4 and 6 bars) were used in this work. it was found that, as the pressure increases, the flux permitted and rejection of elements would be increased, where were the values of maximum rejection of elements 81,90.9,90.9,77.5,80.2,93.9,92.9 and 76.6% for cd, u, pb, cu, zn, k, th, and ni respectively, when operating time 90 minutes and pressure 6 bar. the temperature increases the flux permitted while the rejection of elements was steady state almost with the increase in temperature for all heavy and radioactive elements. it was also shown shows that these a steady-state has stopped after 35 ºc and rejection start to decrease until reaching 75,85.4,86.2,73.8,74,91.2,86.2 and 69% for cd, u, pb, cu, zn, k, th, and ni respectively. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction phosphogypsum (pg) can be defined as a solid waste by-product that is created throughout phosphoric acid’s production from the phosphate rocks with the use of the process “wet acid” al-hwaiti et al. [1]. this waste has been presently responsible for more than 90% of the production of phosphoric acid. globally, generating pg has been approximately 280 million tons per year (2010) perez-lopez et al. [2]. yet, just 15% regarding the production of pg in the world has been recycled as building materials zhou et al. [3], agricultural fertilizers, soil amendments, and asset manufacturing portland cement degirmenci et al. [4]. the other 85% regarding the production of pg in the world have been disposed of with no treatment. such by-product has been dumped typically in the large stockpiles, and after that subjected to weathering processes, occupy significant lands and resulting in damage to the environment (chemical and radioactive contamination) shweikani et al. [5]. phosphogypsum mainly consists of calcium sulfate dihydrate (caso4.2h2o) and contains a high level of impurities originating from the source phosphate rock that is utilized in the production of phosphoric acid. from such impurities, radionuclides from 238-u and 232-th decay series have been a major concern because of their radiotoxicity. furthermore, there are other elements; including heavy metals and rare earth elements (rees) have http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ waleed t. rashid et al. /al-qadisiyah journal for engineering sciences 13 (2020) 240–245 241 been enriched in pg. the united states environmental protection agency (usepa) defined pg as “technologically enhanced naturally occurring radioactive material” (tenorm), since it generally consists of trace amounts regarding thorium, uranium, in addition to daughter products from actinides decay chains (radon and radium) calin et al. [6]. approaches to remove metal ions from the aqueous solutions majorly involve physical methods as well as chemical ones. traditional methods to remove metal ions from the aqueous solutions were fumigation, flotation methods, ion exchange, filtration, chemical precipitation, electrochemical treatment, adsorption on effective charcoal, etc. santos et al. [7]. in this study, reverse osmosis has been used to remove heavy and radioactive elements from the leach solution, because this method has advantages in removing contaminated elements. efficient use of the (ro) membrane has been documented for the transaction of cr and cyanide metal-plated wastewater abdullah et al. [8]. in the membranes, the separation of the particle fulfillment in a sieve-like approach, in which the membrane’s small pores allow the passage regarding extremely small molecules whereas retaining large particles. ro can be considered as a separation process which applies pressure for forcing solutions through a membrane, retaining the solute on one side as well as allowing the passing of pure solvent to the other. in such case, the membrane is considered to be semipermeable, which means that it will allow the passage regarding solvent, yet not for the metals. the ro membranes utilized are the dense barrier layer in a polymer matrix in which the majority of separation takes place. ro has the ability to remove different types of ions and molecules from the solutions; ro includes diffusion method so that the separation efficiency will be based on water flux rate, pressure, as well as solute concentration papageorgiou et al. [9]. many ways used the recuperation of trace elements with various acids from phosphogypsum, however, they are economically expensive and have a negative environmental impact. this study has chosen water as the solvent for the phosphogypsum treatment and recovers the heavy and radioactive elements. in addition, reverse osmosis is often used to treat hospital waste and wastewater. in this study, used the reverse osmosis method as a complement to the leaching process to remove heavy and radioactive elements. 2. material a representative sample of the phosphogypsum (which was used in this study) was obtained from the al-qaim fertilizers complex at the al-anbar government. fig. 1, shows the main mineralogical phases of the phosphogypsum sample which are (calcium sulphate) with other secondary minerals such as dolomite and brucite, where can be seen, the percentage of calcium sulphate has the largest proportion with a few percentages of dolomite and brucite impurities, while calcium sulphate was (93.6%), dolomite (2.4%), brocite (4.1%). table 1 shows the chemical analysis of the sample which was performed by x-ray fluorescence (xrf). the atomic absorption spectroscopy type (nova aa 350) at ibn-sina state co . labs. used to determine the dissolved heavy and radioactive elements in the solution of the leaching process. figure 1. xrd pattern of phosphogypsum table 1. xrf analysis of the sample symbol concentration % symbol concentration % mgo 3.536 2zro 0.00014 3o2al 0.0038 5o2nb 0.00014 2sio 1.152 mo 0.00072 3o2p 2.006 ag 0.00114 3so 46.42 cd 0.00020 cl 0.05028 2sno 0.00107 o2k 0.0675 5o2sb 0.00236 cao 36.91 te 0.00101 2tio 0.0082 i 0.00159 5o2v 0.0061 cs 0.00040 3o2cr 0.00073 ba 0.02104 mno 0.00067 la 0.00020 3o2fe 0.01769 ce 0.00020 coo 0.00039 hf 0.00010 nio 0.00185 5o2ta 0.01523 cuo 0.00334 wo3 0.00020 zno 0.00890 hg 0.00010 ga 0.00005 2tio 0.00011 ge 0.00005 pbo 0.00114 3o2as 0.00007 bi 0.00010 se 0.00005 th 0.00010 br 0.00024 u 0.00150 o2rb 0.00006 y 0.00285 sro 0.6326 242 waleed t. rashid et al. /al-qadisiyah journal for engineering sciences 13 (2020) 240–245 3. procedure of reverse osmosis fig. 2, shows the reverse osmosis unit used. phosphogypsum sample was used for each one of the tests, the feed should be prepared initially through dissolving the needed quantity of phosphogypsum (0.64 g\1l) jalhoom1 et al. [10], in deionized water with stirring speed 600 rpm contact time 30 min., temperature 45 °c, and particles size (-710 +75µm). the solution from the feed tank has was pumped with various pressures, in which pressure change via close regarding reject water’s valve, which installed after pumps and before entering the membrane chamber (cell). the reading of feed stream pressure gauged for getting the required pressure for all operations. following water preparation, depending on the needed specifications as well as pressure regulation, flow rate as well as other parameters as indicated, the system has been operating for not less than two minutes to reaching steady state. meanwhile, permeate as well as the rejected water will be returning to the feed tank to maintain the concentration of water. then, permeate and feed solution has been collected in a flask for testing amount regarding radioactive and heavy metals for calculating membrane rejection as well as determining permeate flow rate to estimate membrane flux. the operating condition using the reverse osmosis membranes process was commenced with the following: operation pressure, time, and temperatures. in this work, heavy and radioactive elements, that had been selected (ni, zn, pb, cd, cu, k, u, and th). figure 2. reverse osmosis unit 4. performance of the reverse osmosis system 4.1 rejection calculated the percentage of heavy and radioactive element rejection was calculated by using equation (1) al-masri et al. [11]. r(%) = (c1−c2) c1 × 100 (1) where (𝑹) represents the rejection percentage, (𝑪𝟏), (𝑪𝟐) represent the concentration of the elements in the feed and in the permeate in the (mg/l), respectively. the elements concentrations in the permeate and the feed was determined using atomic absorption spectroscopy. 4.2 permeable flux calculated permeate flux can be considered as the quantity regarding permeate created throughout membrane separation for each time as well as membrane area. flux will be measured in liters for each square meter per hour. solution permeability was measured to investigate the membrane performance. the permeable flux has been determined by equation (2) gunatilake et al.[12]. 𝐽 = 𝑉 𝐴×𝑡×𝑝 (2) where (𝐽) (l/m2.h.bar) is the permeable flux, (𝑉) (liter) is the volume of permeate, (𝐴) (m2) is the effective membrane surface area, (𝑡) (hour) is the time and (p) (bar) is the pressure. 5. results and discussion 5.1 effect of pressure and time on permeate flux many factors are affecting the ro membrane performance. the main factors to be considered are temperature, time, and pressure. fig. 3, shows the impact related to pressure on permeate flux under conditions, pressure (2-6) bar, time (220) minutes, and temperature (25) ºc. it can be seen that increasing operating pressure from 2 to 6 bar led to an increase in permeate flux. this phenomenon can be explained by darcy’s law stating that increasing the pressure will consequently increase permeate flux moslehyani et al. [13]. higher pressure indicates that high driving force has been utilized across the membrane for pushing water molecules to pass through its semi-permeable membrane which might lead to higher permeates flux arahman et al. [14]. fig. 3 displays the impact of experiment time on permeate flux. the findings of this study show that the contact time has little effect on the permeate flux probably due to the concentration polarization in the system. concentration polarization occurred because of the increment in the osmotic pressure that exists due to the tendency of water for moving from low solute concentrations to high solute concentrations. the effect of concentration polarization will result in reduced flux nicolaisen et al. [15]. figure 3. effect of pressure on permeates flux by ro membrane 0 20 40 60 80 100 0 50 100 150 200 250 f lu x ( l /m 2 .h ) time (min) 2 bar 4 bar 6 bar waleed t. rashid et al. /al-qadisiyah journal for engineering sciences 13 (2020) 240–245 243 figs. 4,5 and 6 show the impact regarding pressure and experiment time on removing ni, zn, pb, cd, cu, k, u, and th elements for the ro system. under conditions, the pressure (2-6) bars, time (60-120) minutes and temperature (25)°c. it might be indicated that removing metal ions will be increased with the increase in pressure from 2 bars to 6 bars. similar results were obtained by r. w. baker et al. [16]. this behavior because of is occurred due to the membrane does not prevent elements in the feed solution passing completely; therefore some elements pass through the membrane exists. in the case of increasing the pressure, the solution (solvent) will be pumped through the membrane at a high rate in comparison to metals ions zhou et al. [17]. this relationship is in agreement with previous researchers that studied the effect of transmembrane pressure on ions rejection through the membrane separation process. higher pressure lead led to a denser and compacted membrane structure algureiri et al. [18]. as the membrane becomes more compact, molecules other than water will have difficulties passing through the membrane, hence increasing the rejection of molecules other than water in the treatment process arkhangelsky et al. [19]. figs. 4, 5, and 6 show the effect of time on the removal related to radioactive and heavy elements. it might be specified that the percentage rejection regarding radioactive and heavy elements increases slightly as time is increased; the removal efficiency has been improved because of fouling. because of the fouling that arises with increased working time, there will be a decrease in the radius of the pores, which will cause difficulty in the passing of the metal ions, where similar results were obtained by vignesh nayak et al. [20], when increasing operating time, the removal of heavy elements was increased. the order of rejection is k˃th ˃pb˃u˃cd˃zn>cu>ni, presumably this result is due to reject the elements that have a large radius best than others that have a small radius. figure 4. effect of time on rejection ions by ro membrane at 2bar figure 5. effect of time on rejection ions by ro membrane at 4bar figure 6. effect of time on rejection ions by ro membrane at 6 bar 5.2 effect of temperature and time on permeate flux and rejection during the ro process. fig. 7, shows the effect of the temperature on heavy and radioactive element rejection (ni, fe, pb, ca, cu, k, u and th), for reverse osmosis system under conditions the pressure (6) bar, time (60) minutes, and temperature (25-45 )ºc. fig. 7 demonstrates the effect of temperature on the rejection of heavy and radioactive elements. it can be seen that the rejection was steady-state to little decrease that slightly decreased proportionally with the increase in temperature for all heavy and radioactive elements. it also shows that these a the steady-state has stopped after 35 ºc and rejection starts to decrease. this process is occurred, because the membrane active work is in the temperature range of (2535º c). also it's material building at such conditions. the temperature’s increase in within 0 20 40 60 80 100 cd u pb cu zn k th ni r e je c ti o n ( % ) elements 60 min. 90min. 120 min. 0 10 20 30 40 50 60 70 80 90 100 cd u pb cu zn k th ni r e je c ti o n ( % ) elements 60 min. 90 min. 120 min. 0 10 20 30 40 50 60 70 80 90 100 cd u pb cu zn k th ni r e je c ti o n ( % ) elements 60 min. 90min. 120 min. 244 waleed t. rashid et al. /al-qadisiyah journal for engineering sciences 13 (2020) 240–245 such range results in an imbalance in the membrane as well as pores’ expansion that allows the pass of many ions across the membrane, which will be reducing the rejection process’s efficiency. lastly, with when the temperature is increased (more than 35°c) as a result in of decreasing the element’s elements removal since the elevated temperatures is occurred as a result in changes of the membrane material and holes expansion hence, will result in cause membrane damage which will allow entry of minerals and salts dramatically with the pure water moideen et al. [21]. such results have been in almost in accordance with s. riaño et al. [22]. fig. 8, displays the impact of temperature on permeate flux at pressure of (4) bars and time for (60) minutes and temperature (25-45) °c, for the ro membrane. the permeate flux increasing increases clearly with increasing temperature. temperature increase led to an imbalance in the membrane structure therefore causing pores to expansions that allow the transit of a large amount of solution, also this is because of the decrease in the viscosity of water when increasing the temperature of feed water. the results are in good agreement results agreed with the previous work of s. abdulmuttaleb mohammed et al. [23], also from fig. 8 it is can see be seen that the effect of the time on permeate flux, with as when increasing the operating time from 5-60 minutes, there is a slight decrease in permeate flux, this can be attributed to fouling. figure 7. effect of temperature on rejection of ro membrane. figure 8. effect of temperature and operating time on rejection of ro membrane. 6. conclusions this study leads to the following conclusions: 1. both rejection and the permeation flux increase when increasing the pressure. 2. increasing the rejection of heavy and radioactive elements with increasing time, while the permeation flux decreases when increasing the time. 3. the permeation flux is increasing with increasing temperature. 4. the rejection was steady-state almost with the increase in temperature until (35 °c) then decreases with the increase in temperature till (45°c). references [1] m. al-hwaiti, k. a. ibrahim, and m. harrara, “removal of heavy metals from waste phosphogypsum materials using polyethylene glycol and polyvinyl alcohol polymers,” arab. j. chem., 2015. 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[23]. s. abdulmuttaleb mohammed, areej dalaf abbas , laith salim sabri,” effect of operating conditions on reverse osmosis (ro) membrane performanceincreasing journal of engineering ,number 12, volume 20 ,2014. https://www.researchgate.net/profile/bjarne_nicolaisen?_sg=wqgotaujpahsudkk6xu4gumddgpsuilggczimte7tx6ko-ur9-e9i10g1u4hxac9jwefvve.rsppihmkkwv-hn8r3hn0428j_-6e0thlu-vd3hlfoglyn8w2lrxt71swxmq0pfzuzjroa3mp8p5txsbogosulq article al-qadisiyah journal for engineering sciences 13 (2020) 183–188 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hassan299ali@gmail.com (hassan a. shamkhi) https://doi.org/10.30772/qjes.v13i3.705 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. simultaneous extraction of lead, copper, and cadmium from aqueous solution using emulsion liquid membrane technique hassan a. shamkhia a*, amer d. z. albdiria a a chemical engineering department college of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 2 june 2020 received in revised form 14 july 2020 accepted 20 july 2020 keywords: emulsion liquid membrane simultaneous extraction of heavy metals emulsion stability extraction efficiency emulsification a b s t r a c t a simultaneous extraction study of lead, copper, and cadmium from diluted aqueous solution through emulsion liquid membrane (elm) technique was conducted and extensive investigations of the impact of the ph of the feed phase, homogenizer speed, surfactant (span 80) and carrier (d2ehpa) concentrations, and ratio of external to membrane phase on the system stability (breakage) and removal efficiencies of pb2+, cu2+,cd2+ ions were experimentally carried out. kerosene was used as the membrane and stabilized by sorbitan monooleate (span 80) as the emulsifier. bis-2-ethylhexyl phosphoric acid (d2ehpa) as an extractant and h2so4 as a reagent (internal phase) were utilized. lead, copper, and cadmium extraction efficiencies of 100%, 100%, and 98% were obtained respectively under specific operating conditions. the emulsion stability of the system was studied, and breakage of 1.8% under the best operating condition was obtained. high reagent (h2so4) concentration (0.5 m) maintained the simultaneous extraction of the three heavy metals (lead, copper, and cadmium) and minimizes the probable interaction and competing mechanism between them in the extraction stage. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction large quantities of wastewater containing heavy metals are annually dumped in the environment h. ma et al. [1]. heavy metals have dangerous effects on health and environment. if wastewater containing heavy metals is directly disposed to surface water, sea, and groundwater, it strongly affects the lives of organisms begum et al. [2]. heavy metals such as; lead, copper, cadmium, zinc, nickel, mercury, silver, iron, chromium, gold, arsenic, cobalt, molybdenum, aluminum and manganese can be absorbed and cumulative inside body of human causing dangerous health problems mahakal et al. [3] .cancer, organ harm, and harm for the nervous system are examples of health problems caused by heavy metals. in particular, copper, cadmium, and lead are considered to be highly toxic minerals. copper results in liver and kidneys damage s. n. h. d. et al. [4], cadmium as carcinogen for humans, also affects kidneys [5][6]. lead causes major damage to immune and nervous systems salman et al. [7] . it also hinders children’s growth. therefore, the removal of heavy metals from wastewaters becomes very important and several separation processes have been developed for this purpose, such as precipitation swain et al. [8], adsorption [9][10], ionexchange khanmohammadi et al. [11], reverse osmosis li et al. [12], electrodialysis and electrochemical [13][14]. http://qu.edu.iq/ mailto:hassan299ali@gmail.com https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 184 hassan a. shamkhia , amer d. z . albdiria /al-qadisiyah journal for engineering sciences 13 (2020) 183–188 emulsion liquid membrane (elm) has emerged as an effective separation process used to remove heavy metals from wastewater nemati et al. [13]. elm mainly depends on concentration difference between external and internal phases through flexible membrane surrounding the internal phase. elm is considered as an easy operation and low energy consumption separation process in comparison with other traditional processes such as reverse osmosis, ultrafiltration, and semi-permeable membrane techniques hussein et al. [15]. the simplicity of elm systems is reflected on its low operating and maintenance costs. extraction and stripping of heavy metal are happened simultaneously when elm is used for the removal of heavy metals from wastewaters resulting in high efficiency process goyal et al. [16]. elm processes can select a component from a solution containing a mixture of minerals [17][18], or remove more than one element at the same time ammar et al. [19]. however, elm’s instability is considered as a major challenge of the process. membrane breakage (leakage) is the main reason of the membrane instability and directly affects the overall elm efficiency mohammed et al. [20]. breakage is defined as the process of leaking the internal phase of the globules, which reduces the stripping agent and consequently reduces the extraction and destabilizes the system pfeiffer et al. [21]. elm consists of two aqueous phases (external and internal) separates by a thin membrane of organic phase. elm assumed as a “bubble within a bubble” the internal bubble represents the internal phase and external bubble represents external phase, where membrane (skin) separates the contents of the two bubbles (phases) from merging. external phase is treated as the feed phase [22][23] . choosing the appropriate membrane components determines the success of the elm which includes the right selection of the organic composition, surfactant composition, carrier/extractant composition, and internal phase composition, these are the most important factors on which the success of the elm system depends abbassian et al. [24] . carriers/extractants like d2ehpa yanlin et al. [25] , tbp mohammed et al. [26] or aliquat336 rosly et al. [27] must suitable to form complexes with the target pollutant and then extract it. the internal phase like h2so4 chiha et al. [28], hcl kusumastuti et al. [29] or naoh das et al. [30], and surfactants like span80 zarandi et al. [31] or eca 4360j kumbasar et al. [17] should also choose carefully because it is the most important part of the system that is related to the stability of the emulsion. when properly selected, it leads to less breakage and swelling. in the elm process, diluents are treated as one of the main components of the organic phase and have a critical function in elm stability. kerosene is one of the most used diluents by researchers because of its easy access to it and the appropriate viscosity, but it remains an environmentally unfriendly component kumar et al. [22]. using elm for removing more than one or two metal ions is rarely found in the literature. this research focuses on extracting three toxic elements (pb, cu, and cd) from an aqueous solution, which mimics the wastewater of the ad diwaniyah refinery. the study was extended to investigate system stability and defining the best operating conditions for it. literature shows that the pb removal from wastewaters was studied by [31][32][7], the cu removal from wastewaters was studied by [33][28][1], and the cd removal from wastewaters was studied by [34][35][25]. 2. chemicals and experimental methods 2.1. chemicals di-(2-ethylhexyl) phosphoric acid (d2ehpa) as the extractant which was purchased from sigma-aldrich (merck, darmstadt, germany). and sorbitan monooleate (span 80) was the non-ionic. surfactant and sulfuric acid (h2so4) was the stripping agent and both were obtained from thomas beaker (mumbai, india). the kerosene procured from al-wasat refineries company/al-diwaniya refinery (iraq, al-qadisiyah) behaved as a diluent. the aqueous solutions were formed using the solid form of lead nitrate, cadmium sulphate and cupric sulphate were obtained also from thomas beaker (mumbai, india). 2.2. emulsion preparation the w/o emulsion was formed through two main steps; starting with adding certain ratios of span 80 and d2ehpa acid to kerosene oil and then mixing it for a short time on a magnetic mixer without heating to maintain the viscosity of the mixture, then transfer the mixture to a suitable glass beaker (use here a 200 ml beaker) to mix with h2so4 solution prepared according to certain molarity using a high-speed sr30 homogenizer. a cold-water bath used when speed higher than 12700 rpm, the speed and time are changed to obtain the best conditions. 2.3. procedure and mechanism extraction during the emulsion preparation process, the outer phase is prepared. in this study, concentrations of 10 ppm of lead, copper and cadmium ions are taken with the ph setting. the emulsion phase is added to the aqueous phase to be mixed by digital mixer for 8 minutes at a speed of 250rpm, after which the samples are drawn and filtered using a filter syringe of 0.22 μm. adding carries which is di-2-ethyl hexyl phosphoric acid (d2ehpa) in this study to the organic phase works to increase the effectiveness and selectivity of separating dissolved ions, as this extractant works on forming a complex with target metal ions to increase extraction. the process of forming complexes is the intermediary of transporting ions from the external phase to the internal phase passing through the organic phase as fig. 1. the extraction and stripping reactions for metals transfer through the oil phase by acidic carriers can be displayed as follows: m+2 + 2hr => mr2 + 2h+ (1) mr2 + 2h+ => 2hr + m+2 (2) where hr is the protonated form of acidic extractants, m2+ is the metal ions and h+ the hydrogen ion. eq.(1) represents the extraction process that takes place by the interaction of the extracted carrier with metal ions to form complexes. as for eq.(2), it refers to the abstraction process that takes place in the inner stage to separate the ion from the complex, while the carrier returns to form other complexes. hassan a. shamkhia , amer d. z . albdiria /al-qadisiyah journal for engineering sciences 13 (2020) 183–188 185 figure 1. extraction mechanisms of elm system. 2.4. analysis and calculations the concentration of metal ions is measured by an atomic absorption spectrometer (japanese 2000) where acetylene gas is used with clean and dry air. the lead element is measured with a wavelength of (283.3 nm) while the wavelength of copper (324.7 nm) and cadmium (228.8 nm). the efficiency of the extraction calculated by the following equation: %𝐸 = 𝐶𝑖−𝐶𝑓 𝐶𝑖 ∗ 100 (3) where; 𝐶𝑖 : initial concentration of (pb2+, cu2+,cd2+) in aqueous external solution, 𝐶𝑓 : concentration of (pb2+, cu2+,cd2+) in aqueous external solution after treatment. instability is one of the disadvantages of this technique, which reduces the extraction efficiency of the solvents. the breakage emulsion (%b) indicates instability, as can be verified using the following equation [20][26][7] [36][28] : %𝐵 = 𝑉𝛪 𝑉𝛪𝛪 ∗ 100 (4) where vii: initial volume of internal phase vi: volume of internal phase leaked into the external phase and can be find from this equation: 𝑉𝛪 = 𝑉𝑒𝑥𝑡. 10−𝑝𝐻𝑖− 10−𝑝𝐻𝑓 10−𝑝𝐻𝑓−𝐶𝐻+ 𝑖𝑛𝑡 ∗ 100 (5) 𝑉𝑒𝑥𝑡 : initial volume of external phase 𝑝𝐻𝑖 : ph of external phase before treated 𝑝𝐻𝑓 : ph of feed phase after a certain time of treated 𝐶𝐻+ 𝑖𝑛𝑡 : the initial concentration of h+ in stripping phase the operational conditions and ranges used in this study, which affected stability and removal efficiency, are included in the table 1. table 1. range of the variation of the operating factors during the elm study. variation range parameter 5800 – 24000 emulsification rotating speed, rpm 2 – 8 d2ehpa concentration, % v/v 0 – 6 span 80 concentration, % v/v 2 6 ph of external phase 100:2 – 100:15 external: membrane phase ratio 3. results and discussion 3.1. effect of homogenizer speed on system stability and extraction efficiency of lead, copper, and cadmium the speed of the homogenizer has shown a considerable impact on the elm system stability and the extraction efficiency. it was noticed that the extraction efficiency of pb2+, cu2+,cd2+ increases as the speed of the homogenizer increases up to a certain limit. beyond that limit, breakage took place and extraction efficiency declined as a function of homogenizer speed as shown in fig. 2. increasing the homogenizer speed from 5800 rpm to 16200 rpm demonstrated a considerable decrease of the breakage from 3.8 to 1.8, and the extraction efficiencies of pb2+, cu2+,cd2+ were found to be 100%, 100%, 98.7% respectively. both breakage improvement and the increase of the extraction efficiencies of pb2+, cu2+,cd2+ were attributed to the formation of smaller droplets size as the speed of the homogenizer increased, which resulted in an increase of the surface area available for solute transport. when the speed of the homogenizer exceeded 16200 rpm, the extraction efficiency of pb2+, cu2+,cd2+ started to decrease and 80% efficiency was attained at 24000 rpm. at the same time, an increase of breakage from 1.8 to 12 was demonstrated at 24000 rpm to indicate that higher speeds of homogenizer would cause droplets collision and coalescences, through which breakage increased and system instability was evidenced. through a review of previous studies, it was found that the optimum speed for each research varied based on the working conditions and the extracted pollutant and its concentration, where salman et al. [7] said that the best speed is 12,700 within 10 min of lead with a concentration pouring to 200 ppm, and 20000 rpm at 4 min in another study chaouchi et al. [37] . a maximum of extraction efficiency at a certain value of homogenizer speed followed by a noticeable decrease was reported in both researcher’s works, and a minimum of breakage value was obtained during their course of work at the same points corresponding to the maximum extraction efficiencies . figure 2. effect of homogenizer speed on the extraction efficiency and membrane breakage (time of homogenizer : 10 min, span80:4%(v/v), 0.5m h2so4, internal to organic ratio: 1, d2ehpa: 4% (v/v), feed ph:4, 8 min and 250 rpm in digital mixer , feed to emulsion ratio: 100/10). 186 hassan a. shamkhia , amer d. z . albdiria /al-qadisiyah journal for engineering sciences 13 (2020) 183–188 3.2. effect of extractant concentration on system stability and extraction efficiency of lead, copper, and cadmium di-(2-ethylhexyl) phosphoric acid (d2ehpa) was used as a carrier to facilitate the transport of organic and inorganic pollutants. d2ehpa has high ability to form complexes with pb2+, cu2+,cd2+ ions hussein et al. [15] and consequently increases the extraction efficiency. a range of 2-8% d2ehpa to kerosene volume ratio was investigated to determine the best value of it. as shown in fig. 3, increasing the d2ehpa to kerosene volume ratio from 2% to 4% resulted in a considerable increase of the extraction efficiencies of pb2+, cu2+,cd2+ from 75%, 75%, 41% to 100%, 100%, 98% respectively. the breakage dropped from 3.8 to 1.8 to indicate better system stability. however, when we continued increasing the volume ratio, a decrease in extraction efficiencies was observed and an increase of breakage value was noticed to indicate system instability. increasing the volume ratio led to an increase of the extractant increased to contribute to membrane viscosity increase and the formation of larger globules which promote swelling phenomenon sengupta et al. [33]. the percentage of the volume ratio of 4% was found to outperform in the extraction of pb2+, cu2+,cd2+ ions from the feed phase at the same time, while different volume ratios were reported when those ions were treated separately[7][28][25] . for pb2+ ions, it was reported to be 4% using d2ehpa as a carrier salman et al. [7]. for cu2+ ions, it was reported to be 20% chiha et al. [28], and for cd2+ ions, the volume ratio was reported to be 4.4% yanlin et al. [25]. figure 3. effect of extractant concentration on the extraction efficiency and membrane breakage (time of homogenizer: 10 min, span80:4%(v/v), 0.5m h2so4, internal to organic ratio: 1, homogenizer speed:16200 rpm, feed ph:4, 8 min and 250 rpm in digital mixer , feed to emulsion ratio: 100/10). 3.3. effect of surfactant concentration on system stability and extraction efficiency of lead, copper, and cadmium the effect of the surfactant (span 80) concentration on the breakage and the extraction efficiencies of pb2+, cu2+,cd2+ ions from the feed phase were examined. the surfactant concentration was varied between 0-6% (v/v %). fig. 4 shows that the breakage exhibited a value of 62% for 0% surfactant (span 80) concentration to indicate high system instability. the high instability of the system was reflected in the extraction efficiencies of the pb2+, cu2+,cd2+ ions to demonstrate low extraction efficiencies of 44%, 55%, and 13% respectively. when the surfactant (span 80) concentration was increased to 2% (v/v %), a significant drop of the breakage value was noticed and a value of 4.9% was obtained. however, the value of the breakage of 4.9% raised the extraction efficiencies of the pb2+, cu2+,cd2+ ions to 82%, 85%, 63% respectively. the maximum extraction efficiencies of the pb2+, cu2+,cd2+ ions were observed at 4% span 80 concentration. both pb2+ and cu2+ ions showed 100% extraction efficiency, while cd2+ ions showed 98% extraction efficiency, and the breakage of the system dropped to the value of 1.8 for 4% surfactant concentration. having continued increasing the span 80 concentration to 6% (v/v %) resulted in a decline in the extraction efficiencies of the pb2+, cu2+,cd2+ ions to demonstrate 76%, 78%, and 71% extraction efficiencies respectively. the breakage also witnessed small increase to a value of 2.3 to indicate slight deterioration of system stability. some studies have reached the same conclusion but lead ions only that the surfactant concentration must not exceed 4% v/v to obtain 99% removal efficiency sabry et al. [32] and also 4% for extraction copper ions only chiha et al. [28]. others offered 6.6 vol% span 80 the optimal choice for the liquid membrane system for extraction cadmium(ii) yanlin et al. [25] . although the increase of the surfactant concentration enhances the system stability and hence increases the extraction efficiency, further increase of span 80 concentration resulted in increasing the membrane phase viscosity and a difficult transport of the pb2+, cu2+,cd2+ ions through the membrane would be occurred. figure 4. effect of surfactant concentration on the extraction efficiency and membrane breakage (time of homogenizer: 10 min, d2ehpa:4%(v/v), 0.5m h2so4, internal to organic ratio: 1, homogenizer speed:16200 rpm, feed ph:4, 8 min and 250 rpm in digital mixer , feed to emulsion ratio: 100/10). 3.4. effect of external phase ph on system stability and extraction efficiency of lead, copper, and cadmium fig. 5 shows the weak dependence of the extraction efficiency of the pb2+, cu2+,cd2+ ions on the ph change of the external phase within the range of 2-6. the low effect of the ph on the extraction efficiency of the pb2+, cu2+,cd2+ ions may be due to small difference between the ph of the internal and external phases, and the poor performance of removal solute at low ph result from the contest of hydrogen ions that released from the acidic extractant in the feed phase as explained noah et al. [38]. it is shown in fig. 5 that the extraction efficiencies of the pb2+, cu2+,cd2+ ions were 85.3%, 87.4%, and 76.6% respectively at ph 2, while the breakage was as high as 12.7 indicating considerable system instability. hassan a. shamkhia , amer d. z . albdiria /al-qadisiyah journal for engineering sciences 13 (2020) 183–188 187 however, increasing ph value to 4 resulted in better performance of extraction and stability. the extraction efficiencies of the pb2+, cu2+,cd2+ ions were 100%, 100%, and 98% respectively. the breakage of 1.8 was obtained at ph of 4 indicating good stability of the system. when the value of ph exceeded 4, the extraction efficiency decreased due to an increase of the difference of osmotic pressure which consequently stimulated the transport of water molecules to the internal phase and caused the swelling phenomenon of the membrane laki et al. [39]. the system continued showing lesser breakage values indicating better system stability as shown in fig. 5. figure 5. effect of ph of external phase on the extraction efficiency and breakage (time of homogenizer: 10 min, d2ehpa:4%(v/v), 0.5m h2so4, internal to organic ratio: 1, homogenizer speed:16200 rpm, span80:4%(v/v), 8 min and 250 rpm in digital mixer , feed to emulsion ratio: 100/10). 3.5. effect of external:emulsion phase ratio on system stability and extraction efficiency of lead, copper, and cadmium the volume ratio of the external to emulsion phases is called treat ratio (tr). tr was found to affect the mass transfer of the elm system, so a range of 100:2 – 100:15 was studied to evaluate the tr effect on the system performance. as shown in fig. 6, lower tr values gave lower extraction efficiencies of the pb2+, cu2+, cd2+ ions and as tr increased to the value of 100:10, maximum extraction efficiencies for the pb2+, cu2+, cd2+ ions were obtained (100%, 100%, and 98% respectively). beyond the value of the tr of 100:10, the efficiency decreased to lower values. system stability followed the same trend of extraction efficiency. the system stability was getting better as the tr increased from 100:2 to 100:10 to show a minimum value of 1.8, but it slightly increased to 2.2 when the tr was increased to 100:15. the obtained results matched that reported in salman et al. [7] . the drop in the extraction efficiencies of the pb2+, cu2+,cd2+ ions beyond the value of tr of 100:10 may be attributed to the swelling phenomenon of the internal globules, and consequently the decrease of the surface area available for mass transfer mahakal et al. 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[39] s. laki and a. kargari, “extraction of silver ions from aqueous solutions by emulsion liquid membrane,” j. membr. sci. res., vol. 2, no. 1, pp. 33–40, 2016, doi: 10.22079/jmsr.2016.15876. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 397 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. energy saving of wastewater pumping using proposed integrated drive systems israa amer dahham, college of engineering, university of al-qadisiyah, ad diwaniyah, iraq. email: israa_amer2013@yahoo.com received on 27 july 2017 accepted on 31 october 2017 published on 30 december 2017 doi: 10.30772/qjes.v10i4.495 abstract: an integrated drive arrangement for a wastewater pumping system was designed and modeled to evaluate the energy saving gained from matching motors with variable frequency drive (vfd) and programmable logic controller (plc). the proposed arrangement utilizes the affinity laws of centrifugal pumps to predict the performance of a pump under different rotational speed conditions. the specific energy (es) is used as a measure of the cost effectiveness of the proposed pumping system. results have shown that a reduction of 10% in pump speed can save 30% in energy of maximum speed. the energy saving potential is carried out for a real-life case study, and a conclusion to replace on-off controllers currently used for most wastewater pumping systems is necessary. the total energy saving account for more than 50% when integrated drive system was applied for a combined sewer pump station. keywords: variable frequency drive (vfd), wastewater pumping systems, integrated drive systems, energy saving, programmable logic control (plc). introduction energy consumption of pumping systems dominates the life cycle cost of wastewater pumps. it may be as high as (35-40%) of the life cycle cost. pumping systems are considered a major consumer of electricity. pump motors receive electrical power (pump power input) and transform it into mechanical work (rotational energy). the rotational energy delivers liquids to higher head (pump power output). many flow control solutions of pumping systems have been reported in the literature. the purpose of the reported solutions is to ensure pump’s operational reliability and to save energy and operational expenses. conventional wastewater pump’s motors operate at constant speed to deliver fixed and predefined flow rate. their running speed cannot be adjusted to save power[1]. recently, many technologies have been developed to adjust the running speed of induction motors and a noticeable reduction in energy consumption has been proven[2]. therefore, variable frequency drives are increasingly used for speed control to reduce pump power input[3]. high efficient motors not only save energy, but also, enhance the operation, reduce the maintenance, and improve the life cycle of the motors[4]. high efficient motor drives are engineered to adapt the flow rate and thereby save power at higher percentage[5]. in european union, pumps consume 160 billion kwh per annum of electricity[6]. pumps are available in various sizes (1 kw to hundreds kws) to satisfy different applications of industry. the most efficient mailto:israa_amer2013@yahoo.com al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 398 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. control system to save energy is speed control. however, using variable speed control in wastewater pumping systems may cause significant fluctuations in the rotational speed of the pumping system, due to the large variations of the influent flow rate. the fluctuations become very complicated when combined sewer pumping system is considered, as the storm water (wet weather conditions) causes high flow rates (23 times of sewage peak flow rate) and consequently the nominal rotational speed of the drive becomes very high. it is not recommended to reduce the rotational speed more than 50% of the nominal speed. if the reduction of speed exceeds the recommended limit (50%), drive losses become very considerable. the following equation estimates the drive losses[7]. pdriveloss = 0.35 pdrivelossnom + 0.1 ( ) pdrivelossnom + 0.55 ( ) pdrivelossnom …….(1) where pdriveloss is the drive losses under reduced frequency and pdrivelossnom is the drive losses under normal operational frequency. t and tnom are working and normal temperatures respectively and f, fnom are reduced and normal frequencies respectively. the factors; 0.35, 0.1, and 0.55 are empirically determined. the losses associated with the use of variable speed control in wastewater pumping systems and the wide range of fluctuations in rotational speed are considered to be the major drawbacks of the vfd system. therefore, the focus of this study is to integrate a plc controller to the vfd to ensure smooth frequency variations when fed to the induction motor, and to avoid the effect of the wide fluctuations in rotational speed of the motor. 1. variable speed drive basically vfd systems transform line frequency into variable frequency in two steps. 1. rectify the sine voltage (vac) to dc voltage (vdc). 2. chopping the dc voltage into small pulses (recreate ac voltage with desired frequency). a vfd consists of three main parts; rectifier, dc-bus, and inverter as shown in figure (1). the first part (rectifier) is responsible for converting the supplied (vac) into dc voltage (vdc). the dc-bus part will function as a power reservoir where capacitors store energy and to eliminate ripples generated. then, inverter draws power from dc-bus and recreates (vac) with new (desired) frequency. figure 1: vfd schematic diagram [typical] the output from the vdf system is fed to a motor that drives a pump. the motor will rotate al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 399 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. proportionally to the supplied frequency according to the following formula: n=120f/p ……………………………………… (2) where n is the motor rotation speed (rpm), f is the supplied frequency, and p is the number of poles of motor’s winding. a typical frequency converter circuit diagram is shown in figure (2) . figure 2: wiring diagram of a typical vfd [ref: roba a. y., technical and financial analysis of using variable frequency drive for water pumps compared with fixed frequency, msc thesis, 2014] the inverter part of the vfd system creates voltages of controllable frequency and magnitude. the output voltage of the inverter can be modeled as[8]: vsa=3/π van-1/3(vbn+vcn) …………………………………………… (3) vsb=3/πvbn-1/3(vbn+vcn) …………………………………………… (4) vsc=3/π vcn-1/3(vbn+vcn) ………………………………………… (5) where; cnbnan vvv ,, : amplitudes of inverter output voltages. scsbsa vvv ,, : instantaneous inverter output voltages when a motor is connected to a vfd, a chopped square voltage will be supplied, and harmonics are expected to be experienced. as these harmonics induce additional heat losses, induction motor needs to be de-rated, a margin between maximum output power and nominal-rated output power is required[9]. however, an excited range of frequencies will be experienced and a probability of exciting one of the system’s natural frequencies will be raised leading to vibrations and noise. therefore, if one of the natural frequencies of a motor is within the duty range of the vfd, this frequency needs to be blocked to avoid probable vibration and noise. a plc was connected to monitor and control a vfd controlled pumping system. this plc-vfd integrated system is aimed to overcome overheating and noise problems associated with using vfds to control induction motors. however, plc-vfd integrated systems have been approached by many researchers to enhance the performance of controlled induction motors. a hybrid method was proposed by takiyar[10] to control induction motors. khan[11] demonstrated energy and cost saving in pulp and paper industry. verma[12] used voltage to frequency ratio (v/hz) supervised by a plc controller to control single phase induction motors. ahir[13] used supervisory control and data acquisition (scada-vfd) system to control 3-phase induction motor. most accomplished research focuses on induction motor’s protection considerations. this work aims to functionally integrate operating system (pumping system), vfd-im (im: induction motor) start and speed control mechanism, and plc controller to enhance both the pumping and the vfd performances. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 400 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 2. pumping system description and analysis wastewater pumping system usually consists of pumps, piping, and valves components. pumps are the main component of the system and the most energy consuming parts in wastewater conveyance and treatment systems. pumps generates pressure that is necessary to lift liquids from a low to high levels and to overcome friction resistances of piping and valves. the most used pumps in wastewater sector are centrifugal pumps. the selection of a pump depends on both process requirements (system characteristics) and pump specifications (pump characteristics). both system and pump characteristics are shown in figure (3). the best operating conditions of the system is the intersection point between the pump and system curves. it is called the best efficiency point (bep). working below the bep may cause cavitations (air bubbles) and working above it may cause high temperature rise (overheating). figure 3: system and centrifugal pump curves [ref. variable speed pumping, a guide to successful applications, us doe, industrial technologies program] however, the bep imposes constant flow rate and speed of pump. wastewater pumping system is a supply-controlled system that is designed to pump influent wastewater continuously. influent wastewaters are time-dependent flows (duration profile) as shown in figure (4) . pumps are normally selected and sized to accommodate the highest flow rate. it is seen from figure (4) that only small percentage of time of the day, wastewater influent runs at maximum flow rate. therefore, pump drive motor is needed to operate at its maximum speed for only small percentage of the time of the day. however, conventional wastewater pump’s motors operate at constant speed to deliver fixed and predefined flow rate, and usually on-off control system based on predefined low and high levels is applied in most wastewater pumping systems. figure (5) shows a pump station of a 46000 population city to be considered as a case study for energy saving scenario using integrated plc-vfd control system instead of the on-off control system. the on-off control system is recognized to consume energy much more than needed and operate at a frequent start-stop operation. the start-stop operation system normally causes additional loads on the power components and increases the temperature rise of the motor (overheating). al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 401 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4: typical muncipal wastewater flow rate of 46000 population city during 24 hrs [author’s estimation based on gds guidelines]. figure 5: a wastewater lifting pump station for 46000 population city [typical] al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 402 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. the pumping station was originally designed to receive combined sewer (sewage and storm water influents). the duration profile of the combined sewer influents is shown in figure (6). the storm water influent (wet weather conditions) is three times the maximum sewage influent flow rate (dry weather conditions). therefore, the designed flow rate of pumps is based on the maximum wet weather conditions flow rate. during the dry weather conditions pumping, pumps become oversized and the frequency of the start-stop operation will be very high, resulting in an excessive loads and overheating. figure 6: combined sewer flow rate of a 46000 population city [author’s estimation based on gds guidelines]. the on-off control system becomes unfavorable in wastewater pumping systems and a trend towards using motor’s speed control system is expanding. the speed control system not only save energy, but also enhance performance and life cycle of the motor[4]. energy saving was economically evaluated using the specific energy concept. the specific energy (es) is a measure of how much energy consumed per a unit of volumetric flow rate. it is expressed as; es=pi/q ………………………………………………. (6) where, pi is the input power and q is the volumetric flow rate. therefore, es is constant when on-off control system is used and variable when speed control is used. the difference between the es of the two control solutions represents the energy saving per volumetric flow rate. the total saving per day is simply the product of es difference (es,vfd -es,on-off ) and the daily volumetric flow rate. es,t = (es,vfd – es,on-off) x q …………………… (7) 3. plc-vfd system modeling the integrated plc-vfd control system for a combined sewer pumping station is shown in figures (7,8,9) . the vfd start-control system of the three pumps is shown in figure (7) . al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 403 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7: vfd start-control of 3 wastewater pumps arrangement the vfd start-control arrangement eliminates the direct-on-line (dol) connection disadvantages (high starting current) and ensures smooth start of the pumps. it is also used as speed controller for the drives of the three pumps. the vfds connection to pumps is shown in figure (8). figure 8: vfd – pumps connection diagram the plc control system is used to monitor both pumping and vfds performance and send control signals to motor drives through an (i/o) module, as shown in figure (9) . al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 404 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 9: plc connection diagram the plc consists of five main parts; digital input module, digital output module, voltage monitoring input, vfds connection and process monitoring (flow meter). the vfds connection and process monitoring part is responsible for acquiring real-time data of motor drives speed and wastewater flow rates. a stored program within the plc relates wastewater flow rate to motor drive speed based on affinity laws and calculates the corresponding speed of the drive. an output signal will be generated and sent to the drives to match the running speed of the motors with the incoming flow rates. 4. results and discussions figure (10) shows the wet and dry weather flow rates of a 46000 population city pumping station. the designed flow rates of wet and dry weather conditions are also demonstrated. as the pumping station was designed for a combined sewer practice, the designed pumping flow rate was based on the combined flow rate. the short period of the rainy season in iraq makes the pumps operate at an oversized conditions for the whole of the year. it is clearly seen that the designed flow rate is twice of the maximum dry weather conditions flow rate and approximately three times the average dry weather conditions flow rates. therefore, separate sewer system was proposed and power consumption calculations were carried out for a sewage sewer pumping system. the power consumed was simulated using affinity laws and shown in figure (11) . it is seen that actual power required for pumping is variable and the designed power available for pumping is constant. as the power available for driving the motors is constant and in excess, the pumping becomes intermittent and start-stop profile will be obtained as shown in figure (12) . al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 405 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 10: combined sewer flow profiles figure 11: power consumption profiles al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 406 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 12: power consumption under intermittent conditions a comparison between designed power and actual required power is shown in figure (13). figure 13: designed and actual power profiles the total power consumed per a day was calculated from the area under the curves. the area under the actual power required to run the motor drive is (298.4673 kwd) and the area under the designed power profile is (501.3624 kwd). if intermittent operation scenario is considered, the area under the designed power curve becomes (355.1317 kwd). however, start-stop operation imposes an additional consumed power due to high starting currents. the additional power was estimated from the motor specifications and it was found (60 kwd), resulting in a total power consumption of (415.1317 kwd). therefore the difference between the designed and actual powers is (116.6644 kwd). it contributes to 39% additional power to be saved using vfd control. figure (14) demonstrates the required frequency to run the motor drive of pumps at a speed proportional to actual flow rates. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 407 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 14: estimated frequency profile the frequency profile was translated into rpm of motor drive and shown in figure (15) . figure 15: rpm profile of motor drive proportional to actual flow rate. as shown if figures (14,15) , frequency and rpm profiles suffer frequent fluctuations and practically very difficult to obtain. therefore, a discretization of the frequency was applied using the plc control system to operate the motor drive at stepped profile as shown in figure (16). a minimum frequency of (25 hz) was assumed to avoid overheating and noise of drivers. it is clearly seen from figure (16) that the frequency was controlled using a plc controller and applied in four ranges during a day. this ensures that the motor drives will operate at four constant rpms during a day, and avoid sudden and frequent fluctuations. this results in 30% energy saving and consequently the cost of operation. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 408 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. figure 16: discretized frequency profile conclusions a vfd-plc integrated system was successfully implemented to control wastewater pumping system. the applied control system has demonstrated a considerable energy saving due to balanced rotor drive rotation speed. the vfd part is effectively control the drive rotation and the plc part monitors both process and voltage. drive’s rotation speed was successfully related to actual flow rate of influent wastewater using affinity laws. the frequency profile was controlled using a plc controller and discretized into four distinctive and smooth ranges to avoid frequent fluctuations of the frequency and consequently keep the vibration of the motor drive to minimum. refrences 1. abb brochure, " abb drives and motors for improving energy efficiency", 2012. 2. ali emadi, energy-efficient electrical motors, 3rd edition, new york, 2004. 3. almeida, a. t., ferreira, f. j. t., both, d., "technical and economical considerations in the application of variable-speed drives with electric motor systems", ieee transactions on industry applications, vol. 41, no. 1, (2005). 4. dhivya nandhini dayanandan, "energy saving and market transformation", master’s program in renewable energy systems, halmstad university, 2016. 5. siemens ag brochure, "energy efficient drives", 2009. 6. national renewable energy laboratory, nrel/br-840-36178, april 2004. 7. v. ruuskanen, m. niemelä, j. pyrhönen, s. kanerva, and j. kaukonen, "modelling the brushless excitation system for a synchronous machine," iet electr. power appl., vol. 3, no. 3, pp. 231-239, may 2009. 8. roba a. y.," technical and financial analysis of using variable frequency drive for water pumps compared with fixed frequency", msc thesis, 2014. 9. vfd recommendations, itt industries, flygt brochure. 10. takiyar, s., chauhan, b.k., "hybrid method for customized control of induction motor", international journal of computer and electrical engineering, vol. 5, no. 4, august 2013. al-qadisiyah journal for engineering sciences vol. 10, no. 4 issn: 1998-4456 page 409 copyright  2017 al-qadisiyah journal for engineering sciences. all rights reserved. 11. khan, s., el-dehaibi, n., "system and equipment problems associated with variable frequency drives in the pulp and paper industry", pulp and paper industry technical conference, p. 131-136, (1995). 12. verma, j.k., bhonsle, d., "automation and control of variable frequency drive using plc", international journal of applied science engineering and management vol 1, issue 3, 2015. 13. ahir, j., pandya, v., mehta, c., "design and development of plc and scada based control panel for continuous monitoring of 3-phase induction motor", national conference on recent trends in engineering & technology, 13-14 may 2011. template for academica science journal journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 203 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. damping sub synchronous resonance in power system using tcsc & svc khalid a. nabhar electrical engineering department, university of basra. email: khalidabd9495@gmail.com basim t. kadhem electrical engineering department, university of basra. email: basim72_sh@yahoo.com abstract: when the steam turbine-generator is connected with series of compensation along the transmission line, the sub synchronous resonance may happen. the flexible ac transmission system (facts) controller of the devices wide use which has been used to reduce and suppress the phenomenon of sub-synchronous resonance the thyristor control series compensation (tcsc) and static var compensation (svc) are the types of facts controller that has been used to put down the ssr and also for the purpose of provide a better and efficient solution to improve the transferred capacity system to connect the series compensation along the transmission line. series capacitor work to increase the chance of creating sub synchronous resonance. series capacitors also have an inclination to amplify the shaft stress during considerable network transien toccurrence, ssr phenomena happen which can cause damage of the shaft generator turbine. the first standard model of ieee was adopted to study this phenomenon. this research deals the pid control of svc( static var compensation) and tcsc (thyristor controlled series compensator) and excitation system controller for reducing ssr in power system. in this research, the method of eigenvalue was used to analysis the sub-synchronous resonance phenomenon and the result was verified using dymola simulation keywords: series capacitive compensation, sub synchronous resonance, tcsc, svc, eigen value, facts device, torsional oscillation. 1. introduction the power consumption by the utility is subsequently increased continuously. the increase in power demand had compelled the power engineers to use long transmission line which enables bulk power transfer. in order to satisfy the load demand in long transmission lines, series of capacitive compensations are being used which increase the power delivering capability of the transmission line effectively. further, it also improves the transient stability of the system [1]. because of series capacitive compensation the problem of sub synchronous resonance may occur in long transmission lines. the ssr problem relates to the torsional interactions between the generator rotor section and turbine section of the plant. the interactions between these two masses are caused due to sub harmonic frequencies produced by the series capacity compensator [2]. this interaction causes shaft failure in the turbogenerator system. this phenomenon was first experienced in the year of 1937 but it got noticed in the 1970s after two turbine-generator shaft failures occurred at the mojave generating station in southern nevada [3]. the ssr problem is further divided into two categories namely, torque amplification (ta) also known as transient torque and steady state ssr. the steady state ssr is further divided to torque interaction (ti) and induction generator effect (ieg) [4]. in this paper ti problem is taken into consideration which bears a threat to power system. a flexible ac transmission system is journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 204 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. used in power system to improve power quality, power security and its integration. the facts devices have several uses in the power system but mainly they are used for reactive and real power compensation, to improve power system stability both transient and steady state, to control the line impedance, to suppress the harmonics, to improve the power factor of the system and even to mitigate the ssr problem. to suppress the sub harmonic oscillations there are many facts devices like static synchronous compensator (statcom), static voltage compensator (svc), static series synchronous compensator (sssc), unified power flow controller (upfc) and thyristor controlled series compensator (tcsc) that can be used in the system . this paper uses tcsc and svc as facts devices for eliminating the ssr problem from the system due to the several advantages of this type over other facts devices. have been used for reducing torsional oscillation in series capacitive compensating system for the analyzing of ssr, ieee first benchmark model (fbm) the simulation results of these devices are obtained from dymola software by considering two systems first without facts devices and second with facts appliances. these results are then compared to know the effectiveness of tcsc & svc on reducing of ssr oscillations. shashidhara mecha kotian, [5]. in this research, a dynamic phasor-based continuoustime model of tcsc has been used to result the phaseresponse characteristies of a system analysis. this conversely can, the used of the known the mechanism phase compensation to designing a additional sub-synchronous damping control. it is found that at higher series compensation levels, the designing relys on the change in the fring angle of the thyristor control series compensation tcsc is an important type of type which is increasingly used in long transmission lines in modern power system. r. zheng,[6]. in this research, the sub-synchronous resonance phenomenon is suppressed by using modern control to control the tcsc. various from traditional sub-synchronous damped control, this planner include used solitary local measure that may be effective acquired at the thyristor control series compensation direction. tcsc is a type of series appliance which allows moving fast also uninterrupted transmission line variable impedance [7]. can be classified the tcsc as an appliance series compensation, be possible numerous profits for a power system as well as a control process, flow power during transmission line reducing oscillation mode, as well as put out the status and resonance that appear [8]. for this purpose, the ieee benchmark first model, in fig.1, that is submitted for studying ssr phenomenon in three cases has been used: 1. without any compensation . 2. compensation by tcsc. 3. compensation by tcsc &svc. with one symmetrical three phase short circuit exc gen lpa lpb mp hp xt xl rl xc xs xp synchronous generator 892.4 mvr xsys 0.14j j 0.5 0.02 turbine figure.1.ieee first benchmark model vt eq [9] journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 205 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2. system model 2.1. power system the study system is the ieee benchmark first modeling [10]. for ssr analysis, described in fig.1.(892.4 mva/ 500 kv/ 50 hz/ 3600 rpm) connect the synchronous generator into the infinite bus passing through transmission line with tcsc &svc with capacitor is constant or whose inductance is different through the control values angle thyristor can be control in its value terminal voltage. shaft consists of several pieces, including one piece for high pressure and one for medium pressure and two pieces of low pressure and generator and exciter system. the shift frequency system has five torsional modes at 98 rad/sec, 127rad/sec 161 rad/sec, 203 rad/ sec, 298 rad/ sec. the machine using in the study consists of two damper winding in quadratic axis while have one damper winding in direct axis, one winding afield were considered. the electrical and mechanical systems were modeled using the dymola program. the complete electrical and mechanical data for the studied system are presented in reference [11]. 2.2. excitation system the main aim of the excitation system is to equip the direct current to the synchronous generator windings. it consists of a system of excitation protection units as well as an automatic regulator of voltages and exciter [12]. an integrated control loop can be inserted as well as a power system stabilizer capability that provides additional signal for the control loop to eliminate sudden disturbances that may adversely affect the process of damping [13]. the excitation considered her is ieee sta1 as seen in fig.2. the automatic voltage regulator (avr) used is the so called strong action automatic excitation regulator shown in fig.3. the purpose of this work is design pid control to a system of excitement to give enhancement to the static and dynamic stability of the power system. figure (2) excitation system modeling [14] vin 1 𝑇𝑘𝑜𝑝. 𝑠 + 1 emax emin δefd efdo efd journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 206 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure (3) excitation system modeling [14] 2.3. static var compensator (svc) the dynamic filter which uses thyristor to modulate the current by way of a shunt connection reactor be possible using to retaliation the ssr problem. the capacitive reactance portion is virtual to be confirmed and reactance portion is taken as changing one by making used of the thyristor switching. the reactor can always be symbolized as controlled voltage source conduct a constant reactor [15]. svc is used to regulate the reactive power and get a better stability for the system voltage the ∆𝑈𝑝 is a signal auxiliary stabilizing and is added to the input current of the svc controlled ∆ia to reducing the torsional mode and inertial. can be used the (tcr) a thyristor controlled reactor as the model of svc in the study. fig.4. exhibits the mathematical model used to control of svc. v1 v3 v5 v6 v7 v4 𝐾𝑖𝑓 . 𝑠 𝑇𝑖𝑓 . 𝑠 + 1 𝐾𝑜𝑢 𝑇𝑜𝑢 . 𝑠 + 1 𝐾1𝑢 . 𝑠 𝑇1𝑢 . 𝑠 + 1 𝐾𝑜𝑤 . 𝑠 𝑇𝑜𝑤 . 𝑠 + 1 𝐾1𝑤 . 𝑠 𝑇1𝑤 . 𝑠 + 1 𝐾𝑤 . 𝑠 𝑇𝑤 . 𝑠 + 1 δv δv δw δif σ vin v2 is intermediate result of this block journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 207 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2 figure (4) modeling of static var compensation[17] 2.4 thyristor controlled series compensation (tcsc) by observing fig.1.find that tcsc is composed of a capacitor that is in a parallel state with an inductor join to the thyristor in a corresponding way through the change in the firing angle of the thyristor. note the change in the inductor value conclude from this case that the tcsc can be considered as variable impedance power system perform tcsc can be used for improvements, namely, enhancing system stability, damping of power oscillations compensating transmission line reactor increasing or controlling power transfer. due to its flexible control, it becomes an effective device for damping the electromechanical and sub synchronous oscillations. tcsc can operate in capacitive or inductive mode. to change the operating mode of tcsc, firing angle of thyristor is controlled. although capacitive mode can be consider to be main control mode [16]. the equivalents modeling of tcsc are represented in fig.5. the terminal voltage input into tcsc across fixed capacitor error ∆𝑈𝑐 the signal auxiliary ∆𝑊𝑐 is add to ∆𝑈𝑐 to reduce the inertial and torsion oscillation modes. 𝐾𝑜𝑢𝑐. 𝑠 𝑇𝑜𝑢𝑐. 𝑠 + 1 𝐾1𝑢𝑐. 𝑠 𝑇1𝑢𝑐. 𝑠 + 1 σ 1 𝑇𝑝. 𝑠 + 1 σ ∆𝑈𝑐 ∆𝐼𝑎 bpmax bpmin bp bpo ∆bp 𝐾𝑖𝑙𝑟 journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 208 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 3. ssr analysis the process of exchange between electrical and mechanical systems is called the ssr phenomenon. to analyze this phenomenon we need to represent the electromechanical systems of the generator units and the electronic dynamics of the electromagnetic transport network. in this research we will use the method of eigenvalue for study the ssr in equation 1 description of some electrical and mechanical quantities miδˈˈi + diiδˈi + ∑ [dij i+1 j=i−1 (δˈi − δˈj) + kij(δi − δj)] = tmi − tei − − − − ( 1) for n-mass system it can be written as: [𝑀]δˈˈi + [𝐷]𝛿ˈ𝑖 + [𝐾]δi = [tmi] − [tei] = [𝑇] − − − − − (2) where [m] is a diagonal matrix, consisting of inertia of all masses, [d] and [k] are tri-diagonal symmetric matrix consisting of damping coefficient and spring coefficient of the various mass sections. [tm] and [te] are the n-vectors of mechanical and electrical torques. [te] has only one non zero element corresponding to generator rotor. now if 𝑋 = [𝛿1𝛿2𝛿3𝛿4𝛿5𝛿ˈ1𝛿ˈ2𝛿ˈ3𝛿ˈ4𝛿ˈ5]ᵗ − − − − − (3) 𝑋ˈ = [[𝛿ˈ1𝛿ˈ2𝛿ˈ3𝛿ˈ4𝛿ˈ5𝛿ˈˈ1𝛿ˈˈ2𝛿ˈˈ3𝛿ˈˈ4𝛿ˈˈ5]ᵗ − − − − − (4) eq. (4) can be written as: δˈˈ𝑖 = −[𝑀]‾¹[𝐷]𝛿ˈ𝑖 − [𝑀]‾¹[𝐾]𝛿𝑖 + [𝑀]‾¹[𝑇𝑚𝑖 − 𝑇𝑒𝑖] − − − − − (5) ∴ δˈˈ𝑖 = [𝑀𝐷]𝛿ˈ𝑖 − [𝑀𝐾]‾¹𝛿𝑖 + [𝑀]‾¹[𝑇𝑚𝑖 − 𝑇𝑒𝑖] − − − (6) 𝑋ˈ = ⌈ 𝛿ˈ𝑖 𝛿ˈˈ𝑖 ⌉ = [ 0 𝐼 𝑀𝐾 𝑀𝐷 ] 𝑥 + [ 0 𝑀‾¹ ] 𝑇𝑚𝑖 − 𝑇𝑒𝑖 − − − − − (7) ∴ 𝑑𝑥 𝑑𝑡 = [𝐴]𝑥 + [𝐵]𝑢 − − − − − (8) the eigenvalues or the natural torsional modes of the shaft system are calculated from [a]matrix of the state variable model. the ssr analysis is carried out based on the following initial operating conditions and assumptions: 1. the transportation system receives a sum of 1 pu from the generator. 2. the turbine energy inside it is assumed fixed. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 209 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 3.1. analysis of ssr without any damping in the first study, by changing the level compensation from (0% to 100%) we observe that the first ieee standard system will have four unstable frequencies. this unstable frequencies increase the phenomenon of sub synchronous resonance [18].without the control of tcsc and svc, the real part of the eigenvalues corresponding to the various torsional frequencies vary in magnitude and become instability at various levels of series compensation note that there are different levels of compensation series so the torsional frequencies are different in terms of instability and magnitude as shown in fig.6. the table (1) shows the value of real part for each frequency without any damping and using eigen value analysis. figure(6).ssr of first benchmark model with level compensation -0.5 0 0.5 1 1.5 2 2.5 3 0 20 40 60 80 100 120 re a l p a rt e ig e n v a lu e s level compensation mode 1 mode 2 mode 4 mode 3 journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 210 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. table (1) first benchmark eigenvalues 3.2. analysis of ssr with control tcsc fig.5. illustrates the mathmatical model of the tcsc. tcsc can be controlling by using a proportional– integral derivative (pid) controller. many theoretical analysis & field tests of [19], the torsional oscillations are triggered by the use of a rotor signal to create a shooting angle. the modulation firing angle has few effects on ssr. in tcsc use it to indicate the voltage of the line as well as the speed signal of the generator as a feedback for controling the eigenvalue, table (2) shows the values of the torsional mode and the critical levels when controlling the use of the voltage signal as well as the speed indication to control the parameters of tcsc. table (2) first benchmark eigenvalues with tcsc control %compensation level mode 75% 57.14% 39.38% 21.248% -0.29±10.14i -0.22±9.28i -0.18±8.6i -0.242±7.7i 0 2.617±98i 0.0416±98i -0.0184±98i -0.032±98i 1 -0.0398±127i 0.2402±127i -0.036±127i 0.0396±127i2 -0.0793±161i 0.0777±161i0.6062±161i -0.0676±161i 3 -0.0238±203i -0.0253±203i -0.0227±203i 0.7608±203i 4 0.1002±299i0.1002±299i0.1002±299i0.1002±299i5 -5.212±98i -3.52±127i -4.28±161i -4.63±203i elect.mode %compensation level mode 75% 57.14% 39.38% 21.248% -1.24±9.16i 1.08±8.57i-0.928±7.22i -0.821±6.52i 0 -0.0611±98i -0.0986±98i -0.08608±98i -0.0751±98i 1 -0.053±127i 0.04018±127i-0.0578±127i -0.059±127i 2 -0.083±161i -0.069±161i 0.0876±1610.0936±161i3 -0.0276±203i -0.024±203i 0.0085±203i0.058±203i4 -0.1002±299i -0.1002±299i 0.1002±299i0.1002±2995 -1.58±113i -1.64±138i -1.49±174i -0.456±218i elect.mode journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 211 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 3.3. analysis of ssr with tcsc control & svc fig.1. illustrate the tcsc& svc users for the purpose of study. using the pid control of tcsc& svc in order to minimize the occurrence this case and simple stabilizing signals in case controller of svc can be used the signals of current and voltage of the generator. these signals provide additional damping at sub synchronous network frequencies. in case the control of tcsc can be use the voltage signal of the line as well as speed signal of the generator as a feedback for control. the table (3) shows the eigenvalues of the torsional mode and the critical levels when controlling the use of the voltage signal as well as the speed indication to control the parameters of tcsc&svc. table (3) first benchmark eigenvalues with tcsc control tcsc and svc control 4. dynamic result a three phase fault on the machine terminal of duration (0.01 sec) and level compensation 21.248% will be considered here and the response of the integrated power system to this type of disturbance will be studied. %compensation level mode 75% 57.14% 39.38% 21.282% -0.656±9.016i 0.5018±8.57i-0.45±7.85i -0.45±7.27i 0 -0.0116±98i -0.04156±98i -0.04737±98i -0.0452±98i 1 -0.0965±127i 0.0774±127i-0.0845±127i -0.0865±127i 2 -0.1038±161i -0.097±161i 0.102±1610.1045±161i3 -0.0501±203i -0.0466±203i 0.038±203i0.0756±203i4 -0.1002±299i -0.1002±299i 0.1002±299i0.1002±2995 -0.017±118i -0.54±142i -1.001±177i -0.666±221i elect.mode journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 212 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure(7) generator terminal voltage figure(8) electromagnet torque m a g n it u d e ( p .u ) time(sec) m a g n it u d e ( p .u ) time(sec) journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 213 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure(9) torque between generatar and low presure figure(10) generator speed in the above figures (from (7) to (10)) the red line represents the signal after gain calculation and the blue line represent the signal with all gains set to zero (without any control).in fig.7. it can be noted the difference between the voltages signals the red line and the blue line. fig.8. shows the electromagnet torque of the generator which shows the enhancement of stability when the avr and tcsc, svc taken in account. and also note when the occurrence of sub synchronous resonance will cause the non-stability of the system so the use of different control methods for the purpose of obtaining a stable system and the suppression of fluctuations in the system by the use of three types of controllers they are automatic voltage regulation, static var compensation and thyristor control series compensation (tcsc).so after the occurrence of the three phases fault a certain period of time, the system will return the state of stability due to the presence of control. m a g n it u d e ( p .u ) time(sec) m a g n it u d e ( p .u ) time(sec) journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 214 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 5.conclusion in this paper discussed the problem of sub synchronous resonance and that the interaction between the frequencies in the electrical grid and the frequency of the turbine segments are equal at certain values if we change the value of the series capacitor has been discussed. the first ieee standard system was used for the purpose of studying the phenomenon of sub synchronous resonance. the system was analyzed by using eigenvalue the purpose of providing an explanation in case of stability and instability in this analysis. we have four unstable frequencies that lead to problems in the system therefore; different controllers are used for the purpose of improving the stability of the system in addition to damping the sub-synchronous resonance oscillation. this is done by using facts control. in this research two types of facts control are used tcsc and svc. it can be extended, also using advance control techniques like fuzzy and neural network also robust control for the purpose of finding the best values for parameters of svc, avr and tcsc, excitation system to damp the ssr. refrences 1. hossein ali mohammadpour, seyyed mohammad hosein mirhoseini, and abbas shoulaie “comparative study of proportional and ts fuzzy controlled gcsc for ssr mitigation,” power international conference on power engineering, energy and electric drives, lisbon, portugal, pp. 564-569, march 2009. 2.massimo bongiorno, jan svensson, and lennart ängquist “on control of static synchronous series compensator for ssr mitigation,” ieee tranc. power electronics, vol. 23, no. 2, pp. 735-743, 2008. 2. massimo bongiorno, lennart angquist, and jan svensson “a novel control strategy for sub synchronous resonance mitigation using sssc,” ieee tranc. power delivery, vol. 23, no. 2, pp. 10331041,2008. 3. akbar lak, daryoush nazarpour, and hasan ghahramani, “novel methods with fuzzy logic and anfis controller based svc for damping sub-synchronous resonance and low-frequency power oscillation,” 20th iranian conference on electrical engineering, (icee2012), tehran, iran, pp. 450-455, may 15-17,2012. 4. narendra kumar, sanjiv kumar and vipin jain “damping sub synchronous oscillations in power system using shunt and series connected facts controllers,” international conference on power, control and embedded system, allahabad, india, pp. 1-5,2010. 5.shashidhara mecha kotian, and k. n. shubhanga," design of a subsynchronous damping controller using adynamie phasor-based model of tcsc," biennial international conference on power and energy system, 2016. 6. atia adrees, graduate student member, ieee, and jovica v. milanović, fellow, ieee,"optimal compensation of transmission lines based on minimisation of the risk of subsynchronous resonance", ieee transaction on power system,digital object identifier 10.1109/tpwrs.2422775,( 2015). 7. anderson, p. m, agrwal, b.l., van ness j.e, "sub synchronous resonance in power. system", ieee press new york.1990. 8. pillai gn, joyce d,"ssr analysis with a new analytic model of thyristor controlled series capacitor. in: 15th pscc, 2005. 9. luiz a. s. pilotto, willis f. long, and abdel-aty edris, impact of tcsc control methodologies on sub synchronous oscillations," ieee transaction on power deliver,vol,18,no.1,2003. 10. meikandasivam s, nema rk, jain sk. behavi oral," study of tcsc device amatlab/simulink implementation". in: proceedings of world academe of science, engineering and technology, vol. 35; issn 2070-3740., 2008. 11. ieee ssr task force , "first benchmark model for computer simulation of sub synchronous resonance "”ieee trans. power apparatus, syst. vol pas-96, pp.1565–1572, sept /oct, 1997. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 215 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 12. s. tesnjak, g. erceg, r. erceg, d.klarin z. komericki,, "excitation system of thermal synchronous turbo generator,” in power plant features in the meaning of electric power system demands, hep d. d., zagreb.2000. . 13. d. sumina, g. erceg, t. idzotic, "excitation control of a synchronous generator using fuzzy logic stabilizing controller, 2005. 14. r.preece, improving the stability of meshed power network, spring international publishing switzerland, doi: 10.1007/978-02393-9-2,(2013). 15. q. h. wu and b.w. hogg, "robust self-tuning regulation for a synchronous generator", ieee proc. ,pt. d, vol. 135,no. 6, pp. 463-473, 1998. 16. r. j. piwko, c. a. wegner, s. j. kinney, and j. d eden, “sub synchronous resonance trperformance tests of ans. power delivery, vol. 11, pp. 1112–1119, apr. 1996. 17.majdi m. alomari,and jian guo zhu," bifurcation control of subsynchronous resonance using tcsc," commun nonlinear sci numer simulat 16 (2011) 2363–2370. 18. a.e. hammad , m. el sadek, "application of a thyristor controlled var compensator for damping oscillation of sub synchronous oscillation in power system" ieee trans., pas, vol. 103, no. 1 pp. 198212,1984. 19. r. j. piwko, c. a. wegner, s. j. kinney, and j. d. eden," sub synchronous resonance performance tests of the slatt thyristor-controlled series capacitor,‖ ieee trans. power delivery, vol. 11,pp.1112-1119,1996 template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 134 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. experimental investigation on the fresh and hardened properties of concrete incorporating polyvinyl abo dhaheer, m.s., civil engineering department, college of engineering, university of al-qadisiyah al-diwaniyah, iraq e mail: shamelm2000@gmail.com ; mohammed.abodhaheer@qu.edu.iq received on 22 january 2018 accepted on 24 january 2018 published on 14 may 2018 doi: 10.30772/qjes.v11i1.525 abstract: polyvinyl alcohol (pva) has undergone intensive research work that has led to confidence in its utilization in various applications. nevertheless, its utilization as a construction material in the concrete industry still needs to be fully addressed. in this paper, an experimental study was dedicated to investigate the influence of pva on the fresh and hardened properties of concrete. three different strength grades, represented by water to cement ratios (w/c), of 0.4, 0.5 and 0.6, with four different pva dosages of 1, 2, 3 and 4%, by mass of cement, were employed in the preparation of the concrete mixes. concerning the fresh properties, results showed that there was a significant contribution of pva to the workability in all produced mixes, irrespective of w/c ratio. in addition, the initial and final setting time of cement pastes modified with 2% pva were longer than that of the control paste. in term of the hardened properties, results demonstrated that the compressive (fcu) and splitting tensile (fst) strengths of concrete are dominated by amounts of pva in the mix and w/c ratios. with the high and moderate w/c ratios, they increased when up to 2% pva was used, and thereafter decreased. however, with the low w/c, pva did not provide any improvement in the strength, but instead, it decreased the strength when more than 2% was added. the findings revealed also that increasing pva content resulted in a significant reduction in total water absorption (twa) of concrete specimens. the larger the pva contents the lower is the twa of the specimens. keywords: polyvinyl alcohol, compressive strength, tensile strength, slump test, total water absorption introduction the reason why concrete is by far one of the most widely utilized construction material is that it can be formed in preferred formwork with a superior durability, strength, ability to withstand extreme environments and in-situate fabrication. nevertheless, being heterogeneous and porous material, plain and reinforced concrete structures could be prone to inherent defects such as voids, micro-cracks and water-filled pores [1]. mailto:mohammed.abodhaheer@qu.edu.iq al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 135 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. these defects, even prior to load application, can become a serious issue in the concrete structures influencing their strength and durability performance [2]. a judicious choice to overcoming or minimizing the adverse influence of the aforementioned shortcomings is by utilizing fine materials [3-6] and polymers [7-11]. the fine materials assist in modifications of the concrete microstructure, resulting in a least porosity and dense matrix [6]. however, the fine materials, in order to be effective, need to be added in relatively large amounts, in which the concrete will be more costly. on the other hand, polymers, unlike fine materials, can be used in small amounts to enhance the performance of cement paste, cement mortar and concrete products [7-11]. for this reason, different types of polymer additives in the field of concrete industries have been tried, such as; re-dispersible polymer powders, liquid resins, monomers and water-soluble polymers [7]. among the water-soluble polymers, polyvinyl alcohol (pva) has been introduced and exploited in the field of cement-based products [11-17]. reviewing the research work regarding the fresh properties, studies have indicated that up to a certain limit, the incorporation of pva has positive influences on concrete workability and water retention ability [12,14,16]. however, the influences of pva towards the hardened properties of cement-based products have been found to have inconsistent results. in some research work, it was concluded that the addition of pva is accompanied with an improvement of the mix compressive strength [15, 18-19]. according to mannan et al. [18] and kou and poon [19], treatment of oil palm shell aggregate and recycled aggregate with pva showed an improvement in strength performance of concrete specimens. however, kim et al. [12] reported that pva can reduce the compressive strength of cement mortar as it increases the air voids content. regarding the flexural strength, allahverdi et al. [11] reported that with a lower w/c ratio, the cement pastes modified with pva showed a slight decrease in flexural strength. kim et al. [12] concluded that with the addition of pva, no significant changes were observed in flexural strength of cement mortar samples. however, different results were also found in a previous study [20] in which the pva modified cement mortar samples showed a noticeable increase in their flexural strength as compared with unmodified samples. for more details regarding the rule of pva on cement-based products, we refer the researcher to recently published paper [13], where the state of the art review on this topic has been deeply discussed. due to the inconsistent findings and limited literature published about the influence of pva on the properties of concrete, its characteristics behavior and performance still need to be thoroughly addressed. beside that, since no research work (to the best knowledge of the author) has locally been reported until now, it is not clear whether or not the performance of concrete mixes containing pva is still the same when locally available materials are used. therefore, more laboratory work, in this regard, are crucial to drawing reliable conclusions. in this paper, the goal was to experimentally investigating the role of two compositional parameters – pva dosage and strength grade (i.e., w/c ratio) of concrete mixes in their fresh and hardened properties. these mixes, which comprised locally sourced building materials, were examined in the fresh state using setting time and workability tests, and in the hardened state by performing compressive strength, splitting tensile strength and total water absorption tests. 1. experimental program 1.1. materials in this research a locally available type i cement, commercially known "crista", was used. it satisfies iraqi specification (iqs) no.5/1984 [21]. crushed coarse aggregate of 20 mm size and 2.63 specific gravity was used. the fine aggregate (natural sand) with a maximum grain size of 4.75 mm and a specific gravity of 2.60 was used. both the fine and coarse aggregates satisfy iqs no.45/1984 [22]. a solution of pva was prepared by watery dissolving the polymer; 60 g of pva was boiled in 1000 ml water. the solution was then subjected to heating over a period of 10 hours with continuous stirring in a temperature of 100c, and it was then kept overnight at ambient temperature in the lab. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 136 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. 1.2. mix proportioning in this study, a series of concrete mixes using three different w/c ratios of 0.6, 0.5 and 0.4 were carried out. they were designated mixl, mixm and mixh for relatively low, medium and high compressive strengths, respectively. the constituent materials of the prepared mixes were initially chosen with the aid of british mix design procedure [23]. however, the actual constituents (as will be explained later in sectios 3.1 and 3.3) depended on (1) the amount of the mixing water that allowed the slump values of control mixes to vary between 30-60 mm, and (2) the amount of fine aggregate that was adjusted to keep the mass of coarse aggregate constant in all prepared mixes. the mix proportions (per cubic metre) were presented in table 1. pva dosages were 1, 2, 3 and 4% by mass of cement. pva solution had been replaced by an equivalent amount of mixing water and mixed with it before they were added to the remaining ingredients in the mixer. table 1. constituent materials of the tested concrete mixes, kg/m3 mix designation (w+pva)/c* cement fine aggregate coarse aggregate water pva % pva by cement weight mix0l 0.6 335 760 1050 202.0 0.0 0 mix1l 198.7 3.4 1 mix2l 195.3 6.7 2 mix3l 192.0 10.1 3 mix4l 188.6` 13.4 4 mix0m 0.5 380 745 1050 190.0 0 0 mix1m 186.2 3.8 1 mix2m 182.4 7.6 2 mix3m 178.6 11.4 3 mix4m 174.8 15.2 4 mix0h 0.4 445 730 1050 178.0 0.0 0 mix1h 173.6 4.5 1 mix2h 169.1 8.9 2 mix3h 164.7 13.4 3 mix4h 160.2 17.8 4 (w+pva)/c* : figure in parenthesis refers to substitution of pva by an equivalent amount of the mixing water such that w/c ratio becomes (w+pva)/c. 1.3. test procedure in the present study, experimental tests for the fresh and hardened mixes were carried out, including: initial and final setting times, slump, compressive strength, splitting tensile strength and total water absorption. the initial and final setting time tests were conducted on cement pastes according to astm c191-82 [24]. the slump of fresh concrete was measured using the standard slump test apparatus according to astm c143 [25]. for each concrete mix, three cubes of 150 mm and six cylinders of 100 × 200 mm were cast to determine the compressive strength (fcu), splitting tensile strength (fst), and total water absorption (twa), respectively. all specimens were cast in steel moulds and then demolded after 24 hours al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 137 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. and cured in water until the age of 28 days. fcu, fst and twa were measured according to b.s. 1881 [26], astm c496-86 [27] and astm c-642 [28], respectively. 2. results and discussion 2.1. workability to investigate the effect of pva on the workability of fresh concrete mixes, slump test was performed in this study. from an engineering perspective, water content is considered the most important parameter affecting the workability of fresh concrete. to take this issue into consideration, the amounts of water contents in the control mixes (mix0l, mix0m and mix0h) were adjusted by performing trial mixes to maintain slump values in the range of 30-60 mm. to get more precise results of the slump test, pva solution was replaced by an equivalent amount of the water used in the mixes such that w/c ratio was represented by (w+pva)/c. another important parameter of the fresh concrete workability, which cannot be overlooked, is the volume fraction of coarse aggregate (ca). it forms more than 33% of the total mix volume. in order to eliminate any possible influence of this parameter on the fresh properties, ca amounts were kept constant for all prepared mixes. the results of slump test of the present study have been presented in table 2 and graphically plotted in figures 1-2. figure 1 shows that there is a significant improvement in the workability of fresh concrete for all produced mixes, regardless of the mix w/c ratio. increasing pva up to 4%, increases the slump values, with respect to control mix, from 62 to 83 mm, from 35 to 67 mm and from 41 to 85 mm for w/c ratios of 0.4, 0.5 and 0.6 respectively. as indicated in figure 2, the maximum relative slump to the control mix (at 4% pva) is about 148, 191 and 207 for w/c ratios of 0.4, 0.5 and 0.6 respectively. as mentioned above, the workability of control mixes depended on trail mixes to reach the target slump range. this could explain the reason behind the difference in slump values of the control mixes prepared with the chosen w/c ratios. the positive effect of pva on the workability is in agreement with results of a study carried out by allahverdi et al. [11] and kim et al. [12]. the improved workability with the addition of pva is very likely attributed to the enhancement of concrete matrix due to the ‘‘ball bearing” effect of the water-soluble polymer [11, 13]. the other key reason behind that enhancement in fresh concrete workability could be the deflocculating influence of pva on the cement particles in addition to its lubricating effect on the fine and coarse aggregates in the mix. accordingly, it would be worthwhile to examine the role of pva to be used as a water reducing admixture (plasticizer), which in turn, would result in decreasing water demands for a particular mix workability, and thereby, improving its strength. table 2. slump test results of the fresh mixes w/c=0.6 w/c=0.5 w/c=0.4 mix designation slump mm mix designation slump mm mix designation slump mm mix0l 41 mix0m 35 mix0h 62 mix1l 51 mix1m 40 mix1h 76 mix2l 68 mix2m 56 mix2h 84 mix3l 82 mix3m 63 mix3h 80 mix4l 85 mix4m 67 mix4h 83 al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 138 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. figure 1: slump test of the fresh mixes versus pva dosages at different w/c ratios figure 2: relative slump to the control mix at different pva dosages and w/c ratios 2.2. setting time the results of the initial and final setting time of the produced mixes using vicat apparatus [24] are given in table 3 and figures 3-4. apparently from figure 3, both setting times increase when up to 2% pva is added, and thereafter decrease. with respect to the control mix, they increase from 74 to 89 min and from 267 to 300 min, corresponding to an increase of 20% and 12%, respectively, when up to 2% pva is used. however, above this percentage, the initial setting time of cement paste remains longer than that of the control paste. as clearly seen in figure 4, the relative initial and final setting time reach about 116% and al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 139 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. 98% of the control mix, respectively, when 4% pva is added. a possible justification for that increase in the setting time is that the microstructure of cement paste matrix could be altered with the presence of pva, which acts as an agent for inhibiting the hydration of cement particles. it is worth emphasising that the workability and setting time of concrete can be considered as the two key issues influencing its fresh state and hardened state as well [23]. this is of prime importance when planning to cast a concrete mix in a hot weather. without paying attention to this issue, concrete will practically experience a difficulty in its construction process such as, transporting, handling, placing and finishing. based on the above results, the use of pva in concrete industries, particularly in the climates that are characterized by long hot and dry summers, is expected to offer a simultaneous potential in workability (as plasticizer) and in setting time (as a retarder admixture). thus, the influences of aforementioned circumstances on the construction process of fresh concrete can be mitigated. in this regard, it is, however, necessary to use an optimum dosage of pva because its high amount (as will be seen later), might result in negative consequences on the concrete strength. table 3. initial and final setting time test results % pva by cement weight setting time, min. initial final 0 74 267 1 83 285 2 89 300 3 87 269 4 86 261 figure 3: initial and final setting times of cement pastes at different pva dosages al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 140 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. figure 4: relative setting time to the control mix at different pva dosages 2.3. compressive strength the compressive strength (fcu) is considered to be the most important property of concrete structures that provides an indication of their general performance [23]. this property is primerly determined by the water to cement ratio (w/c) under particular parameters. in addition to w/c ratio, concrete mixes are also influenced by the amounts of coarse aggregate (ca) as it typically occupies more than a third of the concrete volume. consequently, changes in ca contents can affect the workability and strength as well. that is, for this reason, the masses of ca in all produced mixes were kept constant (see table 2). this will exclude any possible effect of this ingredient material on the concrete strength, allowing the w/c ratio and pva dosage to be the most important mix parameters controlling its strength. keeping the amount of ca constant, the fine aggregate (fa) was adjusted in all produced mixes such that the total mix volume worked out to be 1 m3, accordingly. the results of compressive strength (fcu) at the age of 28 days are shown in table 4 and plotted for all w/c ratios in figures 5-6. it is indicated that, fcu seems to be dominated by the amounts of pva in the mix and the w/c ratios. with the high w/c ratio (i.e. 0.6), fcu increases moderately (about 11%) when up to 2% pva is used (mix2l) and thereafter decreases, but it remains approximately the same as the control mix at the maximum pva dosage. for the mix with 0.5 w/c, fcu increases marginally (3%) when up to 2% pva is used, and then decreases, as clearly seen in figure 6. the increase in fcu with the addition of pva could be due to the chemical interaction between the pva and cement particles that results in improving mix microstructure and formation some new compounds in the cement matrix [12]. from the other side, in the mixes with a w/c ratio of 0.4 (mix1h-mix2h), which possess the lowest w/c ratio among the produced mixes, the addition of pva does not provide improvements in the compressive strength, but instead, it decreases the strength when more than 2% is added. at 4% pva (mix4h), fcu registered about 90% of the control mix (figure 6). al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 141 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. table 4. hardened properties test results mix designation fcu mpa fst mpa twa % mix0l 24.5 2.25 5.10 mix1l 26.8 2.53 4.78 mix2l 27.2 2.47 4.05 mix3l 26.0 2.35 3.60 mix4l 24.8 2.28 3.38 mix0m 31.4 3.41 4.35 mix1m 31.1 3.56 4.17 mix2m 30.4 3.59 3.75 mix3m 30.1 3.26 3.23 mix4m 29.5 3.05 3.15 mix0h 42.4 4.55 3.44 mix1h 42.0 4.61 3.35 mix2h 41.7 4.46 3.23 mix3h 38.6 4.28 2.78 mix4h 38.0 3.72 2.63 figure 5: compressive strength versus pva dosages at different w/c ratios al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 142 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. figure 6: relative fcu to the control mix at different pva dosages and w/c ratios 2.4. splitting tensile strength the splitting tensile strength (fst) of the prepared mixes (using cylinders of 100 x 200 mm) is indicated in table 4 and figures 7-8. the influence of pva on fst is found to be almost similar to that of compressive strength. with w/c ratio of 0.6, the presence of pva in the concrete mixes demonstrates an increase of about 12% in their fst when up to 2% pva is added (mix1l and mix2l), then it decreases as pva percentage increases. the improved microstructure due to the formation of new compounds in the cement matrix could be the reason behind that enhancement in fst [12]. however, in 3% and 4% pva (mix3l and mix4l), less enhancement in fst is observed. apparently from figure 8, fst is found to have a marginal increase (about 5%) in the mixes with 0.5 w/c ratio, but it has no changes in that of 0.4 w/c ratio when up to 2% pva is added. beyond this percentage, the produced mixes suffer from a reduction in their tensile strength, and this reduction is more pronounced when using 4% pva (mix4h). this could be justified by incomplete hydrolysis of pva due to the relatively lower amounts of provided water (160 kg), which is exhausted in the workability and hydration of the relatively high amount of cement (445 kg) in mix4h. for comparison, allahverdi et al [11] reported that fst of cement paste mixes with 0.3 w/c ratio was found to be two folds of the reference mix when about 2% pva was used. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 143 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. figure 7:splitting tensile strength versus pva dosages at different w/c ratios figure 8: relative fst to the reference mix at different pva dosages and w/c ratios al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 144 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. 2.5. total water absorption from an engineering point of view, porosity or water absorption is one of the important key parameters from an engineering point of view, porosity or water absorption is one of the important key parameters controlling concrete durability. in other words, any reduction in the concrete porosity can yield to an improvement in its durability performance [23]. from the test results presented in figures 9-10, it can be noticed that with the increase in pva contents, there is a considerable reduction in the total water absorption (twa) of the concrete mixes for all w/c ratios. as clearly seen in figure 10, twa of concrete specimens with 4% of pva can be reduced by approximately 24%, 28% and 34% for 0.4, 0.5 and 0.6 w/c ratios, respectively, in comparison with the control mixes. here, it is, however, worth mentioning that while 4% of pva is the optimum amount for reducing twa, the concrete specimens, in term of strength, reach their best performance when up to 2% pva is used. for comparison, the results of twa in this study are in agreement with the findings reported in [11-12]. the positive influences of pva on twa are very likely related to the improved concrete microstructure, which in turn is significantly affected by the interfacial transition zone (itz) between the cement paste and aggregate [16]. the itz of concrete mixes treated with pva becomes denser and more uniform as compared with the untreated mixes [13]. accordingly, promising findings in term of durability performance of concrete specimens subjected to different curing conditions can be expected. in this regard, an extensive experimental study by the author is ongoing. figure 9: total water absorption versus pva dosages at different w/c ratios al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 145 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. figure 10: relative twa to the control mix at different pva dosages and w/c ratios conclusions the main findings of the presented study indicate that pva modified concrete mixes are accompanied with improvements in their fresh and hardened properties, alike. these can be summarized as follows: 1. the initial and final setting time of the cement pastes increase when up to 2% pva is added, and thereafter decrease. however, pva is comparatively more effective in increasing the initial than final setting time. 2. there is a significant improvement in concrete workability with increasing the dosage of pva, irrespective of the mix w/c ratio, although the improvement is less pronounced in the mixes with a relatively low w/c ratio. 3. the compressive (fcu) and splitting tensile (fst) strengths of concrete are controlled by the amounts of pva in the mix and the w/c ratios. with the high and moderate w/c ratios, they increase when up to 2% pva is added. however, with the low w/c, pva does not provide any improvement in the strength, but instead, it decreases it when more than 2% is used. 4. the porosity of concrete specimens is considrably reduced with the addition of pva at all w/c ratios. the higher the pva content the lower is the total water absorption. here, it is interesting to mention that while 2% of pva is the optimum amount for both compressive and splitting tensile strength, concrete specimens in term of porosity as well as workability reach the best performance when pva is increased to 4%. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 146 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. acknowledgment the author is thankful to mr. alshemary (senior lecturer in the chemical engineering department the university of al-qadisiyah) for preparing the pva used in this research work. the author is also grateful to the technical staff of concrete laboratory of engineering consultant bureau in the college of engineering the university of al-qadisiyahfor their assistance during the testing period. references 1. patzák, b. and bittnar, z. modeling of fresh concrete flow. computers and structures, 87, 2009, pp. 962–969. 2. karihaloo, b.l. fracture mechanics and structural concrete. uk: addison wesley longman, 1995. 3. dinakar, p., reddy, m.k. and sharma, m. behaviour of self-compacting concrete using portland pozzolana cement with different levels of fly ash. materials and design, 46, 2013. pp. 609–616. 4. domone, p.l. and illston, j. construction materials: their nature and behaviour. new york, usa: spon press, 2010. 5. dinakar, p., sethy, k.p. and sahoo, u.c. design of self-compacting concrete with ground granulated blast furnace slag. materials and design, 43, 2013. pp. 161–169. 6. siddique, r., khan, m. i. supplementary cementing materials: silica fume. engineering materials, ch:2. springer-verlag berlin heidelberg, 2011, pp. 67-119. 7. eren, f., gödek, e., keskinates, m., felekog˘lu, km, felekog˘lu, b. effects of latex modification on fresh state consistency, short term strength and long term transport properties of cement 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(pva) in cement-based composite materials: a review of its engineering properties and microstructure behavior. constr. build. mater. 107, 2016, 172–180. 14. ohama y. polymer-based admixtures. cem concr res 1998;20(2–3):189–212. 15. singh nb, rai s. effect of polyvinyl alcohol on the hydration of cement with rice husk ash. cem concr res 2001 ; 31(2): 239–43. 16. kim j, robertson re. effects of polyvinyl alcohol on aggregate–paste bond strength and the interfacial transition zone. adv cem based mater 1998 ; 8 (2): 66–76. 17. santos rs, rodrigues fa, segre n, joekes i. macro-defect free cements influence of polyvinyl alcohol, cement type, and silica fume. cem concr res 1999; 29 (5): 747–51. 18. mannan, m.a., alexander, j., ganapathy, c., teo, d.c.l. quality improvement of oil palm shell (ops) as coarse aggregate in lightweight concrete, build. environ. 41 (9), 2006, 1239–1242. al-qadisiyah journal for engineering sciences vol. 11, no. 1 issn: 1998-4456 page 147 copyright  2017 al-qadisiyah journal for enginnering sciences. all rights reserved. 19. kou, s.c. poon, c.s. properties of concrete prepared with pva-impregnated recycled concrete aggregates, cem. concr. compos. 32 (8), 2010, 649–654. 20. knapen, e., van gemert, d. water-soluble polymers for modification of cement mortars, int. symp. polym. concr., guimarães, portugal, 2006, 85–93. 21. iraqi organization of standards, ios 5: 1984, for portland cement. 22. iraqi organization of standards, ios 45: 1984, for aggregate. 23. neville, a.m. properties of concrete. 4th ed. uk: longman scientific group ltd. 1995. 24. astm c191-92, american standard test method, 1993. 25. american society for testing and materials, c143-89a, standard test method for slump of hydraulic cement concrete, annual book of astm standards, (04) (02),1989, pp.85-86. 26. british standard institution, method for determination of compressive strength of concrete cubes, b.s. 1881: part 116: 1983, 3 pp. 27. american society for testing and materials, c496-86, standard test method for splitting tensile strength of cylindrical concrete specimens, annual book of astm standards, vol.04.02, 1989, pp.259-262. template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 246 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. removal of terasil blue dye from synthetic wastewater using low cost agro-based adsorbents hatem asal gzar, assistant prof. dr./civil eng. department/ college of engineering/ wasit university. e mail: hatam_asal@yahoo.com noor qassim sabri, civil eng. department/ college of engineering / wasit university. e mail: engnoorqassim@yahoo.com abstract: natural materials that are readily available in large amounts in nature and easily accessible may be used as low cost additives. the aim of this study is to measure the susceptibility of these locally available materials, conocarpus plant, to improve the quality of wastewater discharged from textile industry. in addition to conocarpus plant, carbonized conocarpus and activated carbon were used as adsorbents in order to make a comparison, and to test which one of the three types give the best efficiency for removing dye. the ability of adsorbents to adsorb dye was studied using batch system; studied parameters were effect of ph, dose of adsorbents, time, and agitation speed. the experimental results showed that the maximum removal efficiency of conocarpus was found to be 87.5% at 50 rpm mixing speed, ph value 3 , mixing time 120 min and the dose of adsorbent was 0.25 g. the maximum removal efficiency for carbonized conocarpus was up to 98.7% at 150 rpm mixing speed, ph value 3 , mixing time was equal to 7 hours and the dose of sorbent was 1.25 g. for activated carbon the maximum removal efficiency was found to be 99% at mixing speed of 200 rpm, ph value 3 or 11, mixing time was equal to 7 hours and the dose of the sorbent was 1.25 g. the above removal efficiencies were obtained at temperature 20 °c. keywords: terasil blue dye, wastewater, adsorption, low cost adsorbent, batch study. introduction the lack of water on the surface of the earth has become one of the biggest problems faced by humans. the population is growing rapidly and thus increasing the need for industrial processes and the consumption of the goods produced by the industries, thus increasing water consumption and increasing pollution. more than half the water is used to meet the needs of the humans and the second half in agriculture and industrial processes (tang and chen, 2002). mailto:hatam_asal@yahoo.com al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 247 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. in addition to water shortages, industrial processes, through the discharge of waste water in the water bodies, lead to serious environmental problems. although the treatment of contaminated water is the responsibility of the environmental protection legislation, most industrial companies in the world do not have processing units, and they are not sufficiently efficient. all these facts are the pressure of industrialists to consider the development and reuse of contaminated water (gökşen et al., 2005). the textile industry is one of the oldest and largest industries which release the contaminants to the environment. the subject of pollutants has been studied by many researchers for many years because it poses a significant risk to the environment due to its chemical nature. the spinning and weaving industries are made up of a large number of steps that are produced by converting natural elements such as cotton, wool, and silk, converting them into fibers and then converting them into cloth through textile and knitting processes and finally finishing them with dyeing, printing and finishing. these steps include processing textiles in chemical baths and often require washing and rinsing. thus, these sequential steps lead to large consumption of water and the production of contaminants in large quantities. textile dyeing is the most important process in terms of pollutant generation and large environmental impacts (gökşen et al., 2005) the polluted water produced by the fabric processes is characterized by large quantities of dye produced by pigments; salts, derived from additives used to stabilize dyes, detergents, complexity factors, fiber residue, high temperature and ph fluctuation. the textile industry, including the textile and dyeing industry, typically produces 200-500 liters of contaminated water per kg of the final product (marcucci et al., 2001). many chemical, physical, and biological processes have been used such as image oxidation and adsorption processes; to remove the chemical dyes used in the dyeing process. at all times, the adsorption process is used to collect chemical dyes on a solid matrix before the biological and chemical treatments (ozmihci and kargi, 2006; aydın et al., 2007). the process of selecting a method of treatment depends on the nature, type, concentration and other components of the liquid contaminants, cost and removal efficiency. common treatment processes such as rainfall and ion exchange are either costly or ineffective in removing pollutants from water. there is a great need for new, cost-effective and efficient ways of treating effluents (ghodbane et al., 2008; figueira et al., 2000). the choice of adsorbent type is an important point in the development of the absorption process. several materials can be used to remove industrial dyes. one of the materials used as a adsorbent is activated carbon powder although it has a high price but it is the most effective material used to remove organic compounds because of large area (1000 m2 g-1) and its high ability to absorb (mohan and karthikeyan, 1997; kestioglu and yalili, 2006; akdemir and ozer, 2013). therefore, it would be correct to use alternative and low cost materials such as agricultural products to be used as an adsorbent; and that these agricultural products are not used only to remove metals but to remove dyes and all solid waste. (satyawali and balakrishnan, 2008; febrianto et al., 2009; sousa et al., 2009). many kinds of agricultural crops have been studied to dispose of dye from sewage, like mud produced by the sugar industry (magdy and deifullah, 1998), rice husk (mckay et al., 1986), peel of orange ( namasivayam et al., 1996) and other agricultural crops like wood ( ho and mackay, 1998), cassava peels and kenaf (hussein, 2016). in this study a new, environment friendly, non-conventional, cost-effective, and locally available conocarpus was investigated for the adsorption of terasil blue dye from synthetic wastewater. the effects of different parameters such as ph, dose of the adsorption, contact time, and agitation speed were studied. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 248 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 1. experimental procedure and methods 1.1 preparation of terasil blue the solution was prepared by dissolving (20) mg of terasil blue dye in 1000 ml of tap water. the dye components (table 1) were examined using eds device (type x – act , usa). the measurements were conducted at the central service laboratory college of education ibn al haitham , baghdad . table 1. the components in terasil blue dye element weight% atomic% c 37.45 50.29 o 35.52 35.81 na 9.89 6.94 s 8.52 4.29 cl 3.72 1.69 br 4.90 0.99 totals 100.00 100.00 1.2 preparation of the adsorbents three adsorbent materals are prepared for adsorption study. 1.2.1 preparation of conocarpus adsorbent conocarpus leaves was taken from the campus of wasit university to be used in this study. the previous studies (hussein et al 2016) was adopted as a working method for preparation of conocarpus in the following steps: cutting the plant’s leaves , and washing them three times by using distilled water to get rid of any dust. after finishing washing, ertw ytht dried in the oven at 110 ° c for 3 hours; then grinded in a mill to a small volume of less than 500 microns. the last step of the preparation process is sieving through (150 300) μm. figure 1 shows the preparation of conocarpus adsorbent. figure 1. preparation of conocarpus adsorbent. 1.2.2 preparation of carbonized conocarpus the previous studies (ramadan et al. 2005) was adopted as a working method for carbonization of conocarpus plants in the following steps: 1. cutting the plant into small pieces. 2. washing it three times with distilled water to to clean it. 3. dry it with a 110 oc for three hours and repeat the drying step for anther quantities until the required quantity is obtained. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 249 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 4. the dried plant is grinded into small granules using grinder. 5. 1: 0.5 of the conocarpus and sodium hydroxide are mixed well. 6. put the mixture in oven at temperature 300 oc for half an hour with continuous flipping.total time for carbonization process was two hours. 7. wash the product in the filtration device twice with distilled water and then washed with hydrochloric acid at a concentration of 10% once to remove the effect of base solution then wash it with water once to remove acidic excitation. 8. the product is then dried in oven at 110 ° c for three hours,then grinded into small granules. 9. sieving the product through (150-300 μm). 1.3 activated carbon the powder activated carbon (pac) (german origin) was used as adsorbent if the experiments (figure 2), its composition are shown in table 2. table 2. specifications of activated carbon. specification value mw 12.01 g/mol soluble in water <0.2% soluble in hcl < 1% soluble in c2h5oh < 0.2% chloride cl <0.001% cooper cu <0.05% iron fe <0.002% lead pb <0.001% figure 2. activated carbon 1.4 batch equilibrium study 100 ml of 20 mg / l terasil blue was poured in flasks of 250 ml size, 0.5 g of adsorbents of activated carbon , conocarpus, and carbonized conocarpus is placed in flasks. ph of the mixture was determined using ph meter. the flasks then placed in orbital shaker (type ts-2,turki) for two hours. centrifugal separator ( type 80-1 electric centrifugal ,taiwan) was used for 15 minutes then filtration process was achieved using filtration device. the final step was analyzing the amount of dye removal using spectrophotometer (type ufb1105014 ,german) with a maximum wavelength of 663 μm (hussein et al 2016). the effect of various parameters, adsorbent dose, ph, contact time and agitation speed were studied. the adsorbed amount qe was calculated using the following equation: al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 250 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved.   o eol e w ccv q   where: qe is the equilibrium uptake (mg/g), vl is the volume of the solution(l), co is the initial concentration(mg/l), ce is the equilibrium concentration(mg/l), wo is the mass of biosorbent. the biosorption removal efficiency was calculated by the difference of the initial and equilibrium concentration of terasil blue dye according to the following equation: removal% =   o eo c cc  ×100 2. results and discussion 2.1 calibration curve solution of terasil dye (1000 mg / l) was used to find the calibration curve. different dilute concentrations were prepared for calibration curve as shown figure 3. figure 3. calibration curve of terasil blue solutions y = 11.639x + 0.0769 r² = 0.9932 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 ab so rb an ce concentration mg/l al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 251 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2.2 effect of contact time on removing of terasil blue using activated carbon, carbonized conocarpus and conocarpus as absorbent materials, the percentage of removal of terasil blue was obtained at different contact times , keeping other parameters constant such as ph solution, sorption dose and shaker rotary velocity. figure 4. percentage of terasil blue removal onto activated carbon , conocarpus plant and carbonized conocarpus at different contacting time, keeping other parameters constant such as ph solution, sorption dose, shaker rotary velocity and temperature 20 . figure 4 shows when activated carbon was used and carbonized conocarpus that dye adsorption increase with increasing time and remains constant after reaching equilibrium. this is due to a larger area of absorbent material at the beginning of the adsorption process. as surface adsorption sites are exhausted, the absorption rate controls the rate at which adsorption from external sites is transferred to the interior of the sorbent molecules. the upper percentage was achieved to remove the dye after about 7 hours of shaking time. the result is consistent with those obtained by sumanjit et al. (2008). when conocarpus is used ,it is apparent that the removal of dye decreases with increasing time, because the plant did not undergo carbonation processes, but only drying, so it kept green color , the more time increases the ability to give the color. the best time for adsorption is at the second hour. from figure 4 it is shown that activated carbon and carbonized conocarpus were more effective in the process of adsorption where the efficiency of removal 98.56% and 98.53% respectively followed by the dried conocarpus plant 59.57%. 2.3 effect of adsorbent dosage on removal of terasil blue the influence of adsorbent dosage on removal efficiency of terasil blue dye has been investigated. five amounts of each adsorbent (0.25, 0.5 ,0.75 ,1, and 1.25 g) were used; at the following conditions: 20 mg/l concentration of terasil blue solution, rotating speed 150 rpm, and temperature 25 oc. figure 5 shows the relationship between the ratio of removal efficiency and different dose of sorbent, of activated carbon , carbonized conocarpus and conocarpus. when the activated carbon and carbonized conocarpus was used, it appears that the efficiency of removal of the terasil dye increases with increasing dosage of the absorbent materials because of the availability of more adsorption sites and increase in the surfaces area of adsorbent , the result is consistent with those obtained by selvaraj et al. (2003). al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 252 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. when conocarpus is used, the efficiency of the dye removal decreases with the increase of mass of sorbents, because the plant was used without carbonization and it is added a green dye to the solution, so the greater the dose the greater the ability to give color and reduce the process of adsorption. figure 5. percentage of terasil blue removal onto activated carbon, carbonized conocarpus and conocarpus , at different dosage, keeping other parameters constant such as ph solution, contact time, shaker rotary velocity and temperature 20 . from figure 5 which represents the relationship between the efficiency of removal and adsorbent dosage, it is shown that activated carbon and carbonized conocarpus were more effective in the process of adsorption where the efficiency of removal 98.63 % and 98.48 %, respectively at adsorbent dosage 1.25 g while the removal efficiency of conocarpus was 76.95 at dosage 0.25 g. 2.4 effect of ph on the adsorption of terasil ph have a significant effect in the adsorption process.ph of solution is effecting the surface charge of the adsorbent and the influences structural stability of terasil blue dye. the effect of ph solution has been study in the adsorption on terasil blue dye and the range was(ph 3-11). figure 6 represents the effect of ph value on each adsorbent of terasil blue dye. the result is consistent with those obtained by woolard et al. (2002). figure 6. percentage of terasil blue removal onto activated carbon, carbonized conocarpus plant and conocarpus plant, at different ph values, keeping other parameters constant such as contact time, sorption dose, shaker rotary velocity and temperature 20 . al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 253 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. the optimum solution ph values for activated carbon were found to be 3 and 11,the removal efficiency was 98.18 % at the two values of ph. the maximum adsorption of terasil blue onto carbonized conocarpus was 98.43% followed by conocarpus 87% at ph 3. 2.5 effect of agitation speed on the a dsorption of terasil blue from figure 7 using the three sorbents (activated carbon , carbonized conocarpus plant , conocarpus), which represents the relationship between the efficiency of removal and agitation speed , keeping other parameters constant such as ph solution, sorption dose and contact time, it is shown that activated carbon, is more efficiency of removal 98.33 % at 200 rpm. followed by carbonized conocarpus plant, where the maximum efficiency of removal 98.31% at 150 rpm, and for the dried conocarpus plant where the maximum efficiently removed 63 % at 50 rpm. figure 7. effect of agitation speed in the adsorption of terasil blue onto activated carbon , carbonized conocarpus plant and conocarpus plant. at different agitation speed, keeping other parameters constant such as contact time, ph solution, sorption dose, and temperature 20 . the speed of vibration affects the physicochemical interaction between the sorbent molecules and the terasil blue dye in the solution. the reduction in the removal efficiency after the speed of 200 rpm is due to the accumulation of part of the sorbent (activated carbon, carbonized conocarpus plant and conocarpus) on the inner surface of the flask neck during the operation of the device which reduces absorption of the dye. therefore 200 rpm considered the optimum agitation speed for the adsorption process. these results are similar to those found by pehlivan and altun., (2008). in the case of ideal conditions for all effects and for all sorbents, the removal efficiency are as follows: the removal efficiency of conocarpus was found to be 87.5% at 50 rpm mixing speed, ph value 3 , mixing time 120 min and the dose of adsorbent was 0.25 g. the removal efficiency for carbonized conocarpus was up to 98.7% at 150 rpm mixing speed, ph value 3 , mixing time was equal to 7 hours and the dose of sorbent was 1.25 g. for activated carbon the removal efficiency was found to be 99% at mixing speed of 200 rpm, ph value 3 or 11, mixing time was equal to 7 hours and the dose of the sorbent was 1.25 g. the above removal efficiencies were obtained at temperature 20 °c. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 254 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. conclusion 1. according to the results, it was found that using higher dosage of the sorbent, activated carbon and carbonized conocarpus plant ; led to greater efficiency of the removal of terasil blue dye. in case of using conocarpus, less efficiency of removal was obtained with increasing the dose of absorbent. 2. it has been shown that ph 3 is the optimum value for the best adsorption process. 3. a higher adsorption efficiency was obtained when more contact time between the adsorbent, activated carbon and carbonized conocarpus plant, and terasil dye. in case of using conocarpus as adsorbent, the increase in time lead to less efficiency of removal. 4. it was found that 200 rpm is the optimum speed for the adsorption process when was used activated carbon,150 rpm when carbonized conocarpus plant use ,and 50 rpm when conocarpus were used. refrences 1. akdemir eo and ozer a (2013) pretreatment of cheese whey effluent using a microfiltration process: a statistical design approach. ekoloji 22(88): 21-27. 2. aydin s, güneysu s and arayici s (2007) investigation of using adsorbents obtained from sewage sludge with pyrolysis for removal of cod and dye from textile industry wastewater. ekoloji 16(64): 4348. 3. figueira, m. m., volesky, b., ciminelli, v. s. t. and roddick. f. a. 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of activated carbon from cocustree residues using modified carbonate and chemical thermal activating, qatar journal of chemistry 18,161-169 19. sumanjit l., tejinder, p., singh, w. and ishu, k., (2008) “ removal of rhodamine-b by adsorption on walnut shell charcoal”, journal of surface science technology,24,3-4,179-193. 20. satyawali, y. and balakrishnan, m., (2008) wastewater treatment in molasses-based alcohol distilleries for cod and color removal, a review, journal of environmental management, 86, 481-497. 21. sousa, f.w., oliveira, a.g., vicente, o.s., netofechine, p.b.a., keukeleire, d., cavalcante, r.m., oliveira, i.r.n., sousajames, m. and nascimento, r.f., (2009) evaluation of a low-cost adsorbent for removal of toxic metal ions from wastewater of electroplating factory, journal of environmental management, 90, 3340-3344. 22. tang, s. and chen, l., (2002). density-dependent birth rate, birth pulses andtheir population dynamic consequences. journal of mathematical biology,(44(2), 185-199). 23. woolard c, strong j, erasmus c (2002) evaluation of the use of modified coal ash as a potential sorbent for organic waste streams. applied geochemistry 17: 1159-1164. article al-qadisiyah journal for engineering sciences 14 (2021) 075–082 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mech.post06@qu.edu.iq (husam jasim farhood) https://doi.org/10.30772/qjes.v14i2.749 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. the effect of using scrap tire powder in the perforated brick holes on thermal insulation husam jasim farhood a*, alaa liaq hashem a a university of al-qadisiyah, college of engineering, department of mechanical engineering, ad-diwaniyah, iraq. a r t i c l e i n f o article history: received 27 april 2021 received in revised form 12 june 2021 accepted 13 june 2021 keywords: scrap tire powder traditional wall insulation decrement factor a b s t r a c t in this study, old scrap tire powder was used with building materials commonly used in iraq, where it was used in some brick holes in the form of powder 0-1 mm ( crumb rubber without fabric and metal), and this case, it was called scrap tire powder in bricks [stp-i]. it was compared with the traditional wall that does not contain scrap tires, called [no sts]. a test room has been build prepared for this purpose and a heating source for 8 hours applied on each wall. the comparison was by measuring the temperatures on the inner and the outer surfaces as well as the center of the wall, and comparing the thermal resistance and the heat transferred. the results noted that the addition of this material might be reducing the internal surface temperature by 2.56℃, which is a good incentive for this material's role as a thermal insulator. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction scrap tires (sts) represent environmental contamination and a public health concern because they can easily become mosquito-breeding sites or can harbor other disease-borne pests mohammed et al. [1]. iraq seeks to recycle millions of tires, unrecognized waste disposal in general increases health risks, and lack of economic benefits. iraq imports 10 million tires from various countries annually according to the statistics of the iraqi ministry of planning to supply more than 6 million cars iraq cso [2]. in iraq, the residential sector accounts for over 46% of total energy consumption mohamed et al. [3] and most of this energy is consumed by air conditioning. the use of thermal insulation to reduce energy consumption in residential buildings is not a common practice. when insulation is used, traditional materials with low thermal conductivity, such as polystyrene, are common jelle [4]. the development of new insulation materials is an opportunity, as there are several disadvantages associated with the use of polystyrenes, such as poor mechanical resistance, solar degradation, and high cost. there are two indirect problems; high-energy consumption due to poor insulation of buildings and misuse of land for st landfills. these problems can be resolved at the same time if the number of sts disposed of is reduced by using them as insulation material in residential buildings and other applications. building sustainability is the main goal that researchers look for in their research, many research had dealt with this topic to achieve the necessary recommendations that would raise the level of practical reality in building design qusay [5]. it was found that the process of sustainability in buildings is achieved by many mechanisms, foremost of which is reducing the cost of electrical energy by reducing the electrical energy spent in the building. the reduction of the cooling and heating in electric power leads to saving money, which is often very expensive, as well as the process of reducing energy consumption, which in turn leads to a reduction in gas emissions from power plants dawood, m.s [6]. some applications of st have been previously reported. http://qu.edu.iq/ mailto:mech.post06@qu.edu.iq%20(husam https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 76 husam jasim farhood , alaa liaq hashem /al-qadisiyah journal for engineering sciences 14 (2021) 075–082 for instance, yesilata et al. [7], reported that st scrap tires may be mixed with concrete for use as construction material in exterior walls in order to increase thermal protection. the use of scrap rubber tires (sts) as insulation gives additional features, such as reducing storage space in landfills, in addition to reducing environmental damage and the risk of combustion. ashraf fadiel et al. [8] showed that with the increase in the volume of added rubber, the thermal conductivity decreases, as the rubber mortar that contains 40% rubber the thermal conductivity equal to 0.492 [w/m. k], which meaning there is a decrease of 28% for conventional mortar. m. romero et al. [9] studied experimentally the thermal performance of scrap tire blocks as roof insulators in residential building roofs. they used rubber blocks with dimensions of 30302.54 cm3 and in both white and black colors. they were placed both on the roof of concrete buildings and studied the thermal performance and the effect of their presence on the temperature inside the room. in addition to studying the surface without block, but in white color from the facing side to the source of manufactured radiation, which simulates solar radiation. the results showed that scrap tire blocks (stbs) had thermal conductivity more than polystyrene but, the ability of stbs to maintain the interior temperature was nearly similar because of the conduction–convection heat transfer mechanism inside stbs. also, they showed that stbs-white was performed better as insulating material. (stbs had rapid loss of heat gain as well as slow gain of thermal energy). this is a good indication of the role of scrap tire blocks in thermal insulation. researchers' recommendations included several opinions on reducing energy consumption, the most important of which was the use of insulators in the outer walls, which would create a comfortable environment for occupants while reducing energy bills. in addition, the sts presented certain positive characteristics, such as moisture resistance, mildew, heat, humidity, ultraviolet rays (from the sun), acids, and other chemicals. in addition, sts show a delay in the development of bacteria. in this study, the focus will be on the efficiency of using scrip tire rubber produced by the tire factory in al-diwaniyah (powder 0-1mm) and recycled from used tires in the holes of the brick units used in the construction of the walls and its effect on the thermal insulation in the building. 2.materials and methods 1.1. materials building materials available in the iraqi market, perforated bricks with dimensions of 812 24 cm3, cement, and sand. the rubber (powder 01mm) made from old tire scrap and prepared in al diwaniyah tire factory /abraj al kut company. powder rubber tire scrap was used in perforated brick holes and a certificate of examination of conformity to the european standard en1177 and as well as perforated bricks and mortar. for two models, the temperature readings for each model are taken by placing the temperature sensors on the outer and inner side of the wall and in the middle of the wall, and by completing the readings, a comparison was made with the results achieved to find out the effect of using scrap tire powder in brick holes. 1.2. thermal conductivity measurements 1.2.1. thermal conductivity for structural materials in this study, thermal conductivity and some other characteristics of structural materials used in building walls, such as perforated bricks and mortar, are according to the details in the table 1. table 1. thermo-physical characteristics of the layers of the wall[10][11] material thickness (m) density (kg/ m3) c (w/m. k) k (w/ m. k) external cement mortar 0.02 2050 1.08 perforated bricks[24mm] 0.24 1880 1.37 0.66 perforated bricks[12mm] 0.12 1880 2.78 0.66 internal cement mortar 0.02 2050 1.08 2.2.2.thermal conductivity for scrap tire powder to calculate the thermal conductivity of scrap tire powder, the properties of this material must be known in table 2 some properties of scrap tires are shown, which are the result of several previous researches. table 2. properties of scrap tires [12, 13] no size in (mm) absorption (%) specific gravity density ton/m3 1 0-5 0.40-.46 2 5-10 5.30-8.9 1.1 0.45 3 10-20 0.8-1.3 1.1 0.48 tire scrap powder takes the shape of the space it contains, when it is placed inside the perforated bricks, it takes the cylindrical shape that contains between its particles the air as shown in fig. (1b). nomenclature c thermal conductance (w m-2 k-1) t-z temperature of test zone(℃) k thermal conductivity (w m-1 k-1) t-e temperature of the external surface(℃) q cond. r heat conduction (w m-2 ) thermal resistance (m2 k /w) t-i (t-i)max temperature of the internal surface(℃) max. temperature of the internal surface(℃) r(no sts) r(stp-i) t-m t-l thermal resistance of wall without scrap tire powder (m2 k /w) thermal resistance of wall with scrap tire powder (m2 k /w) temperature of the middle wall temperature of laboratory(℃) (t-i)min (t-e)max (t-e)min ∅ min. temperature of the internal surface(℃) max. temperature of the external surface(℃) min. temperature of the external surface(℃) air volume fraction husam jasim farhood , alaa liaq hashem /al-qadisiyah journal for engineering sciences 14 (2021) 075–082 77 figure 1. shows bricks with scrap tire powder. therefore, the calculation of the thermal conductivity of scrap tire powder with air in a cylindrical form first, and rubber and air cylinders with bricks second we use the equations listed below to calculate the conductivity of the scrap tire powder;[5]: k=𝑘1(1 − ∅) + 𝑘2(∅) (1) where 𝑘1 is the estimated thermal conductivity for bricks and 𝑘2 the thermal conductivities of scrap tires powder (stp) with air in a cylindrical shape, respectively, and ∅ porosity to powder cylinder scrap tire. to find ∅ : we measured the weight of the rubber placed in a cylindrical shape, which is equal to 15 grams and the density of 430 kg/m3 [14]. to find the volume of rubber in the hole: 𝑣𝑟𝑢𝑏𝑏𝑒𝑟 = 𝑚𝑟𝑢𝑏𝑏𝑒𝑟 𝜌𝑟𝑢𝑏𝑏𝑒𝑟 (2) the volume of air in a single hole in the brick is equal to the volume of one hole minus the volume of rubber in one hole. 𝑣𝑎𝑖𝑟 = 𝑣ℎ𝑜𝑙𝑒 − 𝑣𝑟𝑢𝑏𝑏𝑒𝑟 (3) 𝜙 = 𝑣_𝑎𝑖𝑟/𝑣_ℎ𝑜𝑙𝑒 (4) we substitute the porosity value ∅ into equation (1) to find the thermal conductivity value of the rubber cylinder and the air 𝑘𝑟𝑢𝑏𝑏𝑒𝑟 𝑎𝑛𝑑 𝑎𝑖𝑟 = 𝑘𝑟𝑢𝑏𝑏𝑒𝑟 (1 − ∅) + 𝑘𝑎𝑖𝑟. ∅ (5) in addition, when putting rubber in the holes of the bricks, it is necessary to find the thermal conductivity of this brick that contains rubber and air cylinders in its holes therefore, equation (1) is reused. however, the value of ∅ is found by considering the five holes filled with rubber and air being the porous part of the brick, and finding the size of one hole multiplied by five is the number of holes. 𝑉(𝑟𝑢𝑏𝑏𝑒𝑟 𝑎𝑛𝑑 𝑎𝑖𝑟) = [ 𝜋 4 𝐷4 × 𝐿] × 5 (6) 𝑉𝑏𝑟𝑖𝑐𝑘 = 𝐿 × 𝐷 × 𝐻 (7) to find new ∅: ∅ = 𝑉(𝑟𝑢𝑏𝑏𝑒𝑟 𝑎𝑛𝑑 𝑎𝑖𝑟) 𝑉𝐵𝑟𝑖𝑐𝑘 (8) to find the thermal conductivity of the perforated bricks containing the rubber and air cylinders, by substitute the value of ∅ from equation (8) into equation (1), taking the value 𝑘1 of the perforated bricks is equal 0.66(w/m.℃), [10] the value of 𝑘2 calculated from equation (5)and shows in table 2. 𝐾𝑆𝑇𝑃 𝑤𝑖𝑡ℎ 𝐴𝑖𝑟 𝑖𝑛 𝑏𝑟𝑖𝑐𝑘 = 𝑘𝑏𝑟𝑖𝑐𝑘𝑠 (1 − ∅) + 𝑘𝑆𝑇𝑃& 𝑎𝑖𝑟. ∅ (9) table 3. shows steps to measure the thermal conductivity of scrap tires powder in perforated bricks. type 𝑲𝟏(w/m.℃) 𝑲𝟐(w/m.℃) ∅ 𝑲𝒕𝒚𝒑𝒆(w/m.℃) 1 cylinder stp with air 𝐾𝑆𝑇𝑃 = 0.19[7] 𝐾𝑎𝑖𝑟 = 0.024 [6] ∅=0.112 from eq. (4) 𝐾𝑆𝑇𝑃 & 𝐴𝑖𝑟 = 0.145 from eq. (5) 2 stp with air in 5 holes of brick 𝐾𝑏𝑟𝑖𝑐𝑘12𝑐𝑚 = 0.66 𝐾𝑆𝑇𝑃 & 𝐴𝑖𝑟 = 0.145 ∅=0.08522 from eq.(8) 𝐾 𝑆𝑇𝑃 𝐴𝑖𝑟 𝑖𝑛 𝑏𝑟𝑖𝑐𝑘 = 0.616 from eq.(9) 2.2.3.the experimental model and heat source 2.2.3.1.the experimental model the experimental model involves two parts, a small room (cubic box) to compare two environments (inside and outside the box zone). this because there was a need for a small room inside the laboratory to compare its temperature with the laboratory temperature. the room was created with dimensions 110 cm110 cm 110 cm of sandwiched material with 5 cm in thickness. the wall samples that were used for comparison were fitted in square-shaped open created in one of its walls with dimensions of 60 cm 60 cm. a wooden frame is installed inside that hole with identical dimensions and 5 cm in thickness as shown in fig .2. figure 2. a 3d view for the experimental room (adiabatic box). 78 husam jasim farhood , alaa liaq hashem /al-qadisiyah journal for engineering sciences 14 (2021) 075–082 the external mortar thickness (2cm) powder scrap tires perforated bricks thickness (24cm) the internal mortar thickness (2cm) 2.2.3.2.heat source to simulate solar radiation inside the laboratory, an iron structure was created to carry lamps that highlight the sample under study, which we called a solar simulator. it consisted of the following: •the structure made of iron is a rectangular section 2.5 cm10 cm and with dimensions of inside 50 cm50 cm. this frame is attached to a steel pole ended with a circular base. •the heat generated with four lamps with a capacity of each lamp is 1000 watts, the dimensions of 25 cm15 cm. these lamps are fixed inside the iron structure, as shown in fig .3. •an electrical board that contains a circuit breaker to separate and connect each lamp from the lighting lamps, 4 circuit breakers, each with a capacity of 10 amperes. this board is installed on the side of the iron frame. •a voltage regulator is worked to control the intensity of the incident lighting from the lamps by increasing and decreasing the voltage. the capacity of this regulator is about 10000 watts. figure 3. heat source or solar simulator 2.3. preparing test walls samples test models were built inside the wooden frame with dimensions of 50 cm * 50 cm, consisting of building materials available in the iraqi market, perforated bricks with dimensions of 8 cm * 12 cm * 24 cm, cement, and sand. the rubber powder is made from old tire scrap and prepared in al diwaniyah tire factory /abraj al kut company. powder rubber tire scrap was used in perforated brick holes, it represents the last model. fig .4 shows the experimental setup for each test wall. 1the first model included a conventional wall without scrap tire powder(no sts) 2the second model a conventional wall containing scrap tire powder(stp-i) in the outer perforations line from the wall facing to the heating source as shows in fig .4. (a) (b) figure 4. (a)the first model shows a conventional wall[28mm] without scrap tire powder(no sts), and(b) the second model shows a conventional wall[28mm] that contains scrap tire powder(stp-i) in the front holes facing the heating source. for the test models, after the heat source was turned on for 8 hours on the external surfaces, the temperature readings were taken by placing the temperature sensors type (k) on the outer and inner side of the wall and in the middle of the wall. the readings data was recorded by using a data logger (at4516) and these results are compared with the results achieved from the traditional wall. 1-for first model building a model number one with dimensions of 50 cm * 50 cm * 28 cm inside the wood frame using perforated bricks, sand, cement, and coating from the inside and outside as shown in fig .5. after the wall becomes completely dry, the temperature sensors are installed on the front side of the wall outside the small room and the backside of the wall inside the small room and in the middle of the wall as well, and a sensor is also placed in the middle of the small room to measure the temperature change in it, and then heat is projected by the lighting on it from the solar simulator. as shown in figs 6 & 7. the mechanism referred to earlier in this chapter, which is placed 50 cm from the front of the wall, and the solar simulator is run for eight hours, and the intensity of the incident light is read in units of watts of square meters on the front wall every hour using the solar radiation meter. the multi-channel thermometer measures the temperatures in each sensor in addition to measuring the laboratory temperature during the heating period of the wall using solar simulation. all recorded data are saved in the excel program and shows in fig .8. the internal mortar thickness (2cm) perforated bricks thickness (24cm) the external mortar thickness (2cm) husam jasim farhood , alaa liaq hashem /al-qadisiyah journal for engineering sciences 14 (2021) 075–082 79 figure 5. steps of build model no. 1 figure 6. install sensors on both sides of the wall and in the middle of the room figure 7. apply heat source about 1200 w/m^2 and measurement of temperatures by data logger at4516 2-for second modelwe follow the same steps as in the first model, but by using scrap tires powder in the holes in the bricks (15g/hole), as shown in figs 8,9, and 10. figure 8. put 15g of scrap tire powder into one hole figure 9. put the tire scrap power in the line of the outer holes during construction figure 10. apply heat source and measurement of temperatures in model no.2 80 husam jasim farhood , alaa liaq hashem /al-qadisiyah journal for engineering sciences 14 (2021) 075–082 2. parameters used in this study the range (r): is the difference between the maximum and minimum temperatures (eq. (1)), calculated as follows [5]: r = 𝑇𝑚𝑎𝑥−𝑇𝑚𝑖𝑛 (10) decrement factor: is an important factor in building energy consumption calculations, which is the ratio between an amplitude of the internal wall temperatures to an amplitude of the exterior wall temperatures and symbolized by the symbol (𝑓)[15]. (eq.(2)) 𝑓= 𝐴𝑖 𝐴𝐸 = (𝑇−𝐼)𝑀𝑎𝑥−(𝑇−𝐼)𝑀𝑖𝑛 (𝑇−𝐸)𝑀𝑎𝑥−(𝑇−𝐸)𝑀𝑖𝑛 (11) heat conduction through materials is governed by fourier’s law, which is based on an observation made based on experimental evidence. fourier’s law states that heat rate ( 𝑄𝑐𝑜𝑛𝑑) is equal to the temperature gradient[𝟒]: 𝑄𝑐𝑜𝑛𝑑 = −𝐾𝐴 ∆𝑇 𝑥 (12) the thermal resistance of both the traditional first wall and the second wall containing the scrap tire powder in equations 4 and 5 respectively according to the thermal insulation code[11] 𝑅(𝑁𝑜𝑆𝑇𝑠) = ( 𝑙 𝑘 ) 𝑐𝑒𝑚𝑒𝑛𝑡.𝑝 + [ 1 𝑐𝑏𝑟𝑖𝑐𝑘𝑠24 ] + ( 𝑙 𝑘 ) 𝑐𝑒𝑚𝑒𝑛𝑡.𝑝 (13) 𝑅(𝑆𝑇𝑃−𝐼) = ( 𝑙 𝑘 ) 𝑐𝑒𝑚𝑒𝑛𝑡.𝑝 + 𝑙 𝑘𝑆𝑇𝑃 𝑤𝑖𝑡ℎ 𝐴𝑖𝑟 𝑖𝑛 𝑏𝑟𝑖𝑐𝑘 + [ 1 𝑐𝑏𝑟𝑖𝑐𝑘𝑠12 ] + ( 𝑙 𝑘 ) 𝑐𝑒𝑚𝑒𝑛𝑡.𝑝 (14) 3. results and discussion 1from fig .11, the temperature on the outer surface increased from 25.04℃ to 88.74℃ when the heating source was turned on, due to the heat absorbed at the outer surface. because of the thermal diffusivity, the absorbed heat transferred inside the wall, where the temperature in the middle of the wall increased from 25.1 ℃ to 53.4 ℃ . the inner surface reaches a temperature of 22.06℃ to 31.74℃ after 8 hours from the heating process take off. figure 11. temperatures in external surface t-e, internal surface t-i, and middle of wall t-m in the traditional wall without scrap tires powder (no sts). 2-from fig .12, it finds that the laboratory temperature t-l ranges between 18.1℃-22.3℃, while the temperature of the test zone t-z rose from 18.9 to 29.1 due to convection and radiation from the inner wall. with a difference of 6.8℃ between them, after 8 hours of heating. figure 12. shows temperatures in laboratory t-l and test zone t-z in no sts 3-from fig .13, for case (stp-i) it can be noticed that the temperature on the outer surface increased from 20.24℃ to 89.36℃ when the heating source was turned on, and thus due to the absorption of the outer surface. as shown in case 2, the absorbed heat transferred inside, the temperature in the middle of the wall increased from 24℃ to 48.6℃ and the inner surface reaches a temperature of 20.52℃ to 29.18℃. figure 13. temperatures in external surface t-e, internal surface t-i, and the middle of wall t-m in the traditional wall with scrap tires powder (stp-i). 4-from fig .14, the laboratory temperature t-l ranges between 17.3℃21.9℃, while the temperature of the test zone t-z rose from 18.4℃ to 27.1℃ with a maximum difference reach 5.8 oc at the end of the heating process. husam jasim farhood , alaa liaq hashem /al-qadisiyah journal for engineering sciences 14 (2021) 075–082 81 figure 14. shows temperatures in laboratory t-l and test zone t-z in stp-i from fig. 15 and at a time of 8 hours, we clearly notice the decrease in temperature along the wall in the case of stp-i compared to the traditional wall due to the presence of rubber in the holes, which affected the increase of the thermal resistance of the wall. figure 15 .shows temperatures along the wall in both cases. )nosts) and (stp-i) table 4, summarizes the maximum and minimum temperatures on the interior and exterior surfaces, in addition to the temperature in the middle of the wall for the beginning and end of the 8-hour heating period. the initial and final conditions for both the laboratory and the test room are all explained in the table below. table 3. shows temperatures in the external, internal & middle of the wall as well as test zone & laboratory. section no sts max (℃) min(℃) stp-i max(℃) min(℃) t-e 88.74 25.04 89.36 20.24 t-m 53.4 25.1 48.6 24 t-i 31.74 22.06 29.18 20.52 t-z 29.1 18.9 27.1 18.4 t-l 22.3 18.1 21.9 17.3 from the above table, it was found that the temperature of the laboratory t-l changed about 4 ℃ in the time of operation of the heat source due to the coldness of the atmosphere outside the laboratory, where the walls were tested during the winter season, which increased the transfer of heat by conduction through the laboratory walls to the outside compared to the heat transferred by convection from heat source. 5-from the data in tables 1, 2, and 3 the thermal insulation parameters range on external, internal surfaces, decrement factor (𝑓), and heat conduction, are summarized as shown in table 4 below. table 4. shows the range on external & internal surfaces, decrement factor (𝑓), and heat conduction for both cases (no sts) & (stp-i) section r-e (℃) r-i (℃) 𝑓 q (w m-2) no sts 63.7 9.68 0.15 96.33 stp-i 69.12 8.66 0.125 78.41 from the above results, it can be concluded that the amount of heat transferred through the second wall decreased to 78.41(w/m^2) due to the presence of scrap powder in the holes of the bricks, and this is a good and encouraging indicator in the role of this material st in thermal insulation. also, the inner surface temperature decreased by 2.56℃. the decrement factor also slows down from 0.15 to 0.125, indicating an increase in the wall's ability when adding scrap tire powder to reduce the amplitude of the temperature on the outer surface to that which is on the inner surface. references 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[15] fathipour, r. and a. hadidi, analytical solution for the study of time lag and decrement factor for building walls in climate of iran. energy, 2017. 134: p. 167-180. template for academica science journal journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 153 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. effect of die angle and friction coefficient on temperature and stress distribution in the extrusion process dr. hazim ismael radhi thi – qar university – engineering college mechanical department e-mailhazemismaeel2003@gmail.com dr. lattif shekher jabur southern technical university technical institute of nasiriyah mechanical technics department e-maillsh58@stu.edu.iq abstract: : extrusion, among other types, is one of the most important forming processes due to its high productivity, lower cost and its good ability to improve the physical and mechanical properties of extruded materials. fe simulation was carried out on abaqus software ver.6.9. to study the distribution of stress and temperature which created through the extrusion process. the results of present study are accentuated that, there is a complicated relationship between stress and temperature distribution relative to die angle and friction coefficient. it was found, in the range of tested cases, at friction coefficient of more than ( 0.08 ), for ( 45o ) die angle, the maximum value of temperature is twice higher than that of ( 75o ), hence the die angle has more significant effect on state of stress and temperature than that of friction coefficient. nevertheless, a high die angle ( α = 75o ) emerged low value of maximum temperature due to easily flow of material toward the die orifice. furthermore, there are a gradual increasing of vonmises criterion and temperature with increasing the friction coefficient while they are decreasing with increasing the die angle. keywords: stress and temperature distribution, die angle, friction coefficient, deformation. introduction aluminum and its alloys are extensively used in different forming process to produce long, strong pieces of formed metal from one solid piece. as well as extrusion of aluminum alloys offers a relatively cheap method of producing complex shapes with high geometric tolerance [1]. tiernam p. et al. [2] used finite element analysis to evaluate the influence of reduction ratio, die land height and die angle on the extraction force during cold extrusion of high grade ( aa 1100 ) aluminum. they presented, the largest extrusion force obtained when the die angle, die exit diameter and die land are ( 15o, 5mm, 4mm ) respectively. evan w. albert et al. [3] studied direct extrusion of aluminum wire by fe analysis to mitigate manufacturing defects. they concluded,the increasing the ram velocity leads to decrease both of turbulence and stress irregularities because of time decreasing in which the die surface and billet are in contact. by using port hole die method, the effect of convex die angle that would optimize the strength and a load of hot extrusion process of ( a 16061) alloy of aluminum tube, have been investigated by sangamesh sirsgi et al. [4]. the authors were reported, with the numerical analysis of the process, the maximum stress is created on the corners of square tube. also, finite element simulation employed to study the distribution of strain, mailto:hazemismaeel2003@gmail.com mailto:lsh58@stu.edu.iq journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 154 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. temperature and effective stress of direct extrusion of titanium alloy [5]. they investigated the influence of different design and process parameters on maximum ram speed, applied pressure and strain and stress distribution. adeosun s. o. [6] studied mechanical properties response of extruded aluminum ( 6063 ) alloy by using plain carbon and tool steel dies at different die entry angles. they employed finite element analysis to investigate the effect of die angle on maximum extrusion pressure and hardness of extrudate. they reported that, by taken into account the cost of manufacturing process, plain carbon steel can successfully replace tool steel as a die material without losing the desirable products. and the maximum extrusion pressure and the hardness of extruded parts are increased as the die entry angle increased. tool steel and mild steel dies used to study the extrusion characteristic of cold, hot and annealed billets of wrought aluminum alloy [1]. die angles ranging from (15o to 90o) adopted to measure the extrusion pressure, linear strain, extrusion ratio and surface hardness of extrusion products. the authors concluded, cold extrusion was easier at high die angles than that at lower die angles and the highest linear strain was obtained for cold extrusion billets by using tool steel die with (90o) die angle. also, the results revealed that the tool steel dies achieved superior extrusion response relative to die which made of mild steel.rafid jabbar mohammed [7] utilized commercial finite element code deform – 3d to investigat the type of metal flow and stress distribution of ( al – 1100 ) rod extrusion.the author reported, the finite element model was successfully simulating the stress distribution in direct rod extrusion. he found, the optimum die angle reduces the magnitude of normal, shear and effective stresses. in this present study, fem was employed to investigate the distribution of stress and temperature which created during direct extrusion of commercial aluminum for different values of die angle and friction coefficient. finite element simulation was carried out on abaqus software v. 6.9 [8]. 1. materials and finite element model the billet materials is aluminum alloy which its mechanical and thermal properties are listed in table (1) [9]. figure (1) indicates the fe model of the extrusion process. the analysis is adopted on consideration of coupled temperature displacement condition. the diameter and the length of the billet are ( do = 60 mm, lo = 180 mm ) respectively. the billet goes through a die with an opening diameter of ( di = 40 mm ), it means, the extrusion ratio is ( 2.25, where extrusion ratio = do2 /di2 ).three values of die angle ( α = 45o , 60o and 75o ) and ten values of friction coefficient ( μ ) from ( 0.01 to 0.1; with 0.01 for each step ) are used to study their effect on stress and temperature distribution which generated during the extrusion process. the use of computing software in the simulations of metal forming process, such as extrusion, rolling and drawing, is the most logical approach to achieve the reducing of unnecessary consumption of resources as time, energy and scrap material [3]. fe simulation of this study was carried out on abaqus v.6.9. cax4t elements are used to mesh the billet which is considered as deformable part while the container defined as rigid surfaces. cax4t is a 4 nodes axisymmetric thermally coupled quadrilateral, and 2d meshes of both billet and container are created [5,8,10].the extrusion process is displacement controlled so that corresponding displacement is applied on the top of the billet. table 1: mechanical and thermal properties of aluminum billet [9] properties the values density 2700 kg / m3 young's modulus 69 x 103 mpa poisson's ratio 0.33 conductivity 204 at 0oc w /m.k 225 at 300 oc w /m.k inelastic heat fraction 0.9 specific heat 880 j/ kg k expansion coefficient 8.42 x 10-5 1/k journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 155 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. figure 1 : dimension of finite element simulation model 2. results and discussion 2.1. stress distribution figure ( 2 ) illustrates the location of maximum vonmises stress ( svm ) at a different stage of extrusion process at friction coefficient equal ( μ = 0.05 ) and die angle ( α = 60o ). it is clear that when the billet reaches the first bend in the container, the value of maximum vonmises stress is small ( 131.9 mpa ) because ( at this region ) the billet material starts deforming plastically. then it increases gradually throughout the flow of the billet's material to the die outlet. the maximum value of vonmises stress (251.1 mpa ) occurs at the end of extrusion stage when the extrusion products go out of the die orifice. a similar trend was found with different values of friction coefficient and die angle, and also with the distribution of shear stress ( s12 ) as shown in figures ( 3 ). b a d c figure 2: location of maximum vonmises stresses ( svm ) at different stage of extrusion process for friction coefficient, μ = 0.05 and die angle = 60o. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 156 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. b a d c figure 3 : location of maximum shear stress ( s12 ) at different stage of extrusion process for friction coefficient, μ = 0.05 and die angle = 60o. the change in the state of principle stress ( s22 ) and plastic strain ( pe22 ) for die angle ( α = 60o ) and friction coefficient ( μ = 0.05 ) during the extrusion process can be obviously seen in figures ( 4 & 5 ). from figure (4), it is clear that when the billet material flows throughout the die, the material in the corners of container and die was under compressive stress. also, it can be noticed, the maximum principle stress ( s22 ) which is tensile stress localizes in the surface areas of the extrudate, whilst the compressive stress exists in the core of extruded parts. figure (5) reveals the changes that have taken place in plastic strain ( pe22 ) through the extrusion process. figure 4: distribution of principle stress(s22) of extrusion process for die angle = 60o and friction coefficient, μ = 0.05. figure 5 : distribution of plastic strain ( pe22 ) of extrusion process for die angle = 60o and friction coefficient, μ = 0.05. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 157 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2.1.1. effect of friction coefficient on stress distribution the variation of maximum vonmises stress with friction coefficient for different die angles are shown in figure (6). it is obvious that the increasing of friction coefficient leads to increase the value of maximum vonmises stress. also, it can be seen, there is a significant effect of die angle in such manner; the bigger the die angle, the less value of maximum vonmises stress is. this can be attributed to the bigger die angle achieve more easily flow of billet material through the die, leading to a decrease in the extrusion force that needed to press the billet to go through the die outlet. figure 6: the variation of vonmises stress ( svm ) verse friction coefficient for different die angles. in addition to another parameter that affects on stress and strain state during extrusion process,the frictional condition at the billet – container and billet – die contributes strongly in determining the characteristics of stresses and plastic strain that exist in extruded products. figures ( 7, 8 and 9 ) demonstrates the variation of vonmises ( svm ), principle ( s22 ) and shear ( s12 ) stresses with friction coefficient for ( 60o ) die angles. it is evident that the increasing of friction coefficient leads to increase the maximum values of all stresses. the results accentuated that the maximum values of svm, s22 and s12 are ( 265 mpa, 158.8 mpa and 75.98 mpa ) respectively, and for tested cases, these results attained at maximum value of friction coefficient which is equal to ( 0.1 ). these results mean, as the coefficient of friction increases, larger frictional forces is, so larger extrusion force is needed to overcome this force which resists the material's flow through the container and die. then consequently, higher stresses exist during the extrusion process with a high value of friction coefficient. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 158 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. a b c d e f figure 7 : effect of friction coefficient on vonmises stress ( svm ) for 60 o die angle ; aμ= 0.00, bμ=0.02, cμ = 0.04, d – μ =0.06, eμ=0.08 and fμ = 0.1. a b c d e f figure 8 : effect of friction coefficient on principle stress ( s 22 ) for 60 o die angle ; aμ= 0.00, bμ =0.02, cμ = 0.04, d – μ =0.06, eμ=0.08 and fμ = 0.1. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 159 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 2.1.2. effect of die angle on stress distribution die angle has a direct effect on the level of maximum stresses and strains of extrusion process. the variation of maximum values of ( svm , s22 , s12 ) for different die angles and friction coefficient are shown in figures ( 10, 11 and 12 ). the results were exhibited that the maximum values of stress, strain and contact pressures for ( α = 75o ) die angle are lower than those for ( α = 45o ). it means, the bigger the die angle, the lower values of maximum stress are. this can be attributed to the fact, the bigger die angle achieves more easily flow of the billet's material throughout the die, hence decreasing the extrusion forces that needed to press the billet to go toward the die outlet and consequently fewer values of maximum stresses and strains. these results are consistent with result have been found by adeosun s. o. et al.[1]. a b c figure 10 : effect of die angles on vonmises stress ( svm ) for coefficient of friction μ = 0.06 ; aα = 45o , bα = 60o, cα = 75o. a b c d e f figure 9: effect of coefficient of friction on shear stress ( s12 ) for 60 o die angle ; aμ= 0.00, bμ=0.02, cμ = 0.04, d – μ =0.06, eμ=0.08 and fμ = 0.1 journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 160 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. a b c figure 11 : effect of die angles on principle stress ( s 22 ) for friction coefficient μ = 0.06 ; aα = 45 o , bα = 60o, cα = 75o. a b c figure 12 : effect of die angles on shear stress ( s 12 ) for friction coefficient μ = 0.06 ; aα = 45 o , bα = 60o, cα = 75o. 2.2. temperature distribution the relationship between the maximum temperature and friction coefficient for different die angle is shown in figure (13). it is evident that the increasing of friction coefficient leads to increase the value of maximum temperature.the temperature distribution and location of maximum values of ( 60o ) die angle for different friction coefficient are illustrated in figure ( 14 ). it is clear that the maximum temperature exists on the surface of extrudate part in the region when the material enters toward the die, it is in the interfacial contact surface between the material and wall of the die. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 161 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. a b figure 14 : temperature distribution and location of maximum values for 60o die angle and friction coefficient of ; a μ = 0.02 , b μ = 0.06. 2. 2.1. effect of friction coefficient on temperature distribution the variation of maximum temperature, which generates during the extrusion process for ( α = 60o ) with different values of friction coefficient, is shown in figures 13 and 15. there is a gradual increasing in maximum value of temperature with increasing the friction coefficient. the maximum temperature for (α = 60o ) at frictionless condition is ( 62.77 oc ) and it increases to ( 80.53 oc ) at ( μ = 0.1 ), it means, the the difference percentage is ( 22% ) while for (α = 45o ) and (α = 75o ) are ( 34% and 7.6% ) respectively. these results prove that, the friction coefficient at the interfacial surface between the billet's material and the walls of both container and die, has a significant effect on the level of maximum temperature which created through the extrusion process. this can be explained as; when the friction coefficient increases, more friction force exist between the contact surfaces and it will produce more heat. hence the maximum value of material's temperature which exists inside the die will also increase. these results are consistent with results that have been found by salode a. m. [11]. figure 13 :the releationship between maximum temperature and coefficient of friction for different die angles. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 162 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. a b c d e f figure 15 : effect of friction coefficient o on temperature ( ntii ) for 60o die angle aμ= 0.0, bμ=0.02, cμ = 0.04, d – μ =0.06, eμ=0.08 and fμ = 0.1 on another hand, and despite the fact of, materials deform easily at high temperature due to the softening effect, nevertheless the high level temperature which created through the extrusion process, is undesirable because of the intensity of dead metal zone formation will increases. also, a high temperature affects the elastic and plastic properties of the billet and die material, resulting in increasing the level of plastic deformation of extruded material and/or increasing the deflection of the die [11]. 2.2.2. effect of die angle on temperature distribution the effect of die angle on the maximum value of extruded parts' temperature is shown in figures ( 16 and 17 ). there is a reverse relationship between the die angle and maximum temperature. in the range of tested cases of friction coefficient, the maximum temperature for ( α = 45o ) is higher than that for ( α = 75o ), and for ( μ > 0.08 ) it is more than twice higher. they are ( 106.2 oc, 76.86 oc, 51.74 oc ) at ( μ = 0.08 ) for die angles of ( 45o, 60o and 75o ) respectively. the results are revealed that the maximum temperature is substantially influenced by the die angle in such a manner; a low die angle leads to difficult flow of material throughout the containeranddietowardthedieoutlet,resultingwithincreasing in the friction at billet – container and billet – die interfaces, which caused large amount of heat generation, consequently increasing the process temperature. a b c figure 16 : effect of die angles on temperature ( ntii ) for coefficient of friction μ = 0.02 ; aα = 45o, bα = 60o, cα = 75o. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 163 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. a b c figure 17 : effect of die angles on temperature ( ntii ) for friction coefficient μ = 0.06 ; aα = 45o , bα = 60o, cα = 75o. vi. conclusion the influence of stress and temperature distribution by die angle and friction coefficient have been investigated using finite element analysis. the die angle has a significient effect on temperature distribution of billet ( i.e. high die angle will decrease the temperature distribution and vice versa ). furtheremore, the finite element simulation of process was illustrated that, the maximum values of vonmises stress and temperature are attain at die angle of ( 45o ) and friction coefficient of ( 0.1 ). references 1. adeosun s. o., akpan e. i. and gbenebor o. p. " extrusion characteristics dependence of wrought aluminium alloy on extrusion variables ", american journal of materials science, 2013, volume 3, issue 4, pp. 77 – 83. 2. tiernam p., hillery m. t., draganescu b. and m. gheorghe, " modelling of cold extrusion with experimental verification", journal of materials processing technology ", 168, 2005, pp. 360 – 366. 3. evan w. albert, adam t. barret and timothy f. gallant," study of direct aluminum wire extrusion by finite element analysis to mitigate manufacturing defects", me 259 – computational solid mechanics, final project report, may 7 , 2015, pp: 1 – 14 . 4. sangamesh sirsgi, dr. shrishail kakkeri and nagraji patil, “ extrusion process and parameters involved in experimental and numerical investigation review “, international journal of engineering research and development, volume 11, issu 06, june 2015, pp. 01 – 03 5. maziar ramezani and thomas neitzeert," finite element modelling of hot extrusion of ti – 6al – 4v alloy ", international journal of advanced engineering research and science ( ijaers ), volume 3, issue – 6 , june 2016, issn 2349 – 6495, pp. 45 – 51. 6. adeosun s. o., sekunowo o. i. and gbenebor o. p. " effect of die entry angle on extrusion responses of aluminium 6063 alloy ", international journal of engineering and technology ( ijet ), volume 4, no. 2, february 2014, issn 2049 – 3444, pp. 127 – 134, publications uk. 7. rafid jabbar mohammed," effect of die angle on stress distribution in extrusion process of aluminium rod ", basrah journal for engineering sciences, volume 14, no. 2, 2014, pp. 43 – 50. journal of al-qadisiyah for engineering science vol. 11, no. 2 issn: 1998-4456 page 164 copyright  2018 al-qadisiyah journal for enginnering science. all rights reserved. 8. abaqus cae ver. 6.9, 2009, example problems manual; standard user's manual. 9. el amri abdelouahid and mounir el yakhloufi haddou, " explicit coupled thermo-mechanical finite element of aluminum alloys ", international journal of recent advanced in mechanical engineering (ijmech) volume 4, no. 3, august 2015. 10. maziar ramezani and thomas neitzer,“ computer simulations of direct extrusion of sintered ti – 6 al – 4 v alloy at elevated temperature ", international journal of applied engineering research ", issn 0973 – 4562, volume 11, number 6, 2016, pp: 3848 – 3852. 11. saloda murtaza ali," to study the influence of frictional conditions and die land length on component error and die deflection in cold extrusion by finite element analysis, "metallurgcal engineering ( me ), volume 3, issue 1, january 2013, no. 1, pp. 29 – 38. article al-qadisiyah journal for engineering sciences 14 (2021) 150–161 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: chem.post12@qu.edu.iq (najm abed hamdan) https://doi.org/10.30772/qjes.v14i2.769 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. catalytic oxidative desulfurization of heavy naphtha fraction over a pmn550 catalyst, reactivity and a kinetic model najm abed hamdan a* , mohammed ali mutar b a chemical engineering dept., university of al-qadisiyah, ad diwaniyah, iraq b college of sciences ,university of al-qadisiyah, ad diwaniyah, iraq a r t i c l e i n f o article history: received 6 august 2021 received in revised form 6 september2021 accepted 8 september 2021 keywords: pmn550 catalysts catalytic oxidation of desulphurization (cods) natural zeolites brnsted acid sites external and internal diffusion a b s t r a c t desulfurization of heavy naphtha by a catalytic oxidation process combining hydrogen peroxide with organic and inorganic acids and in the presence of a pmn550 catalyst. this study was conducted to find out the effect of many variables on the efficiency of the process, especially the effect of hydrogen peroxide, the amount of acid, temperature, residence time, weight of the catalyst (0.01-0.6) g, temperature (20-120) c, residence time (20-140) minutes, ratio hydrogen peroxide to heavy naphtha (0.1-0.6) ml and ratio acid to heavy naphtha (0.01-0.175) ml. the catalytic oxidation process depends on all of the above variables. desulphurization of heavy naphtha using organic and inorganic oxidizers in combination with hydrogen peroxide, glacial acetic acid, phathalic acid, malic acid, sulfuric acid and formic acid. the maximum removal of sulfur was with sulfuric acid and formic acid, which are 50%, 55%, respectively. the catalytic oxidation process carried out in two steps: the first step was the catalytic oxidation at a moderate temperature and atmospheric pressure, and the second step was to extract the oxidized mixture with a methanol-water mixture. the efficiency of the catalytic oxidation process carried out in the presence of pmn550 reached 99%. the catalyst was manufactured in the laboratory and a set of catalyst tests were performed on it ft-ir, afm, bet, xrd, and xrf, which proven its efficacy. mathematical models of the relevant reactions were developed to match the experimental results by obtaining the optimal kinetic parameters. using optimization methods, the maximum conversion rate was 99%, at a temperature of 90°c, a residence time 60 minutes and the initial concentration was 651.3ppm. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction sulfur oxides (sox) are emitted to the atmosphere due to the combustion of fuel that is extracted from oil, and this emission constitutes a real threat to environmental deterioration and air quality pollution. it has been recommended all over the world to establish strict regulations regarding sulfur content in fuel to control these emissions [1,2] to avoid environmental degradation. the major partners, i.e. refiners and users, are required to comply with these regulations for minimum or no sulfur emissions. this is possible if sweet petroleum fuels are manufactured in refining units before being supplied to consumers. the most widely used industrial method for removing sulfur compounds is hydrous desulfurization (hds). this process has economic disadvantages due to the requirements of harsh process conditions such as high hydrogen http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 151 pressure and high temperature for the catalytic decomposition of refractory organic sulfur compounds yang [3]. moreover, high activity (hds) catalysts are in demand by the industry [4] , therefore, searching for alternative operations that are low-cost and can operate in moderate conditions. among these alternative processes to traditional hds, bio desulphurization [6,7], desulphurization through adsorption dasgupta et al. [5], electrochemical oxidation wang et al. [9], ionic liquid extraction li et al. [8]and oxidative desulphurization trakarnpruk et al. [10]. oxidation removal is gaining wide popularity in recent years as mentioned in the literature. due to its simple treatments and high efficiency. it consists of two steps: oxidation of organic sulfur compounds with appropriate oxidants, where these compounds are converted into sulfonates and sulfoxides. the second step is to extract these sulfonates because of their relatively high polarity with some appropriate solvents. in the present work, some oxidants were investigated and compared. the oxidants used are hydrogen peroxide in combination with glacial acetic acid, phathalic acid, malic acid, sulfuric acid and formic acid. the catalytic oxidation of heavy naphtha (cods) was carried out using air to aid the system. the present work, we carried out (cods) of heavy naphtha using air assisted performic acid oxidation system in the presence of pmn550 catalysts. the reaction conditions (temperature, time and concentration of oxidants, i.e., h2o2 and formic acid) were optimized. 2. experimental 2.1. materials formic acid (hcooh) from (macklin); hydrogen peroxide h2o2 from (panreacapplichem); acetic acid glacial c2h4o2 (biosolve bv), malic acid c4h6o5 (bdh), phathalic acid c8h6o4 (merck), sulfuric acid h2so4 (thommas baker), methanol ch3ohfrom (pubchem); ethanol c₂ h₅ oh from (merck); distilled water (iraqi local product). 2.2. heavy naphtha experimental work was carried out on sample of midland refineries company/ daura refinery heavy naphtha. table 1 presents the physical characteristics of heavy naphtha. table 1. physical properties of heavy naphtha taken from daura refinery _____________________________________ properties spec. gravity at 15 celsius 0.7377 crude tbp cut points 100-170 co expected astm distillation d86 vol.% time i.b. p 80 min 5% 92 10% 100 20% 106 30% 111 40% 116 50% 122 60% 127 70% 132 80% 138 90% 146 95% 154 e.b.p. 176 t.b. p 98 res. 0.8 sulfur content 651.3ppm ron 40-50 figure (1): process diagram of batch reactor system. 3. preparation and characterization of catalyst (pmn550) natural zeolite is abundant in the iraqi local markets,imported from many sources: india, yemen, china and others. where the focus in this research is on the natural zeolite that is exported (india). after it has been prepared, developed and activated to be suitable for the catalytic oxidation process, for several reasons. first: its abundance, second: its low cost, and third: the nature of its composition. the natural indian zeolite consists of anorthite, albite & hematite rocks. as shown in the x-ray diffraction (xrd) examination. the method preparation, development and activation as a suitable catalyst for catalytic oxidation process (cods). the raw natural zeolite was milled in the laboratory. the crushed natural zeolite was cross-linked by electric sieve shaker for 10 minutes. then, it was dried overnight in an oven at 40°c, then (10g) natural zeolite, was calcined for (4 h) at 550°c.the powder was cooled to room temperature by turning off the furnace before the catalytic oxidation process. the synthesized catalysts were characterized by elemental analysis via xrd surface properties and xrf, ftir, bet, tga and afm analysis. 4. activity tests of the catalysts for ods reactions 4.1.1. batch reactor the batch reactor has been utilized for carrying out sulfur compound reaction of oxidation. in addition, this reaction is carried out in a 500 ml flask with 3 necks and a round bottom. the middle neck is 152 najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 catalyst (pmn55 0) oxidation of sulfur compounds to sulfonates and sulfoxides, sulfone & sulfoxi air com napata low sulphur feedstock, heavy naphtha,with high sulfur content oxidant separation catalyst(fil tration) solution of extract & raffinate of sulfone (raffinate) from heavy naphtha (low linked to vertical condenser that condenses oil feedstock' vapors, allowing only air to get out. the other neck has been utilized as air inlet that’s connected to compressor and the air is going to reach the flask bottom via glass tube, whereas the 3rd neck has been utilized for measuring flask temperature through the insertion of a thermometer into solution inside the flask and for withdrawing sample reaction in the case when the time has approached. the batch reactor is heated and mixed with the help of a heating mantle stirrer. the process diagram as well as the experimental device of ods are shown in the two figs (1) and (2). figure (2): schematic representation of the ods system 4.1.2. catalytic oxidation of desulphurization (cods) of heavy naphtha heavy naphtha ods experiments were carried out using 20 ml of model oil in a 3-neck flask that has a condenser, which was placed in an oil bath that is mounted on a magnetic stirring hot plate. the sample was treated with 2.5ml formic acid, 2 ml h2o2, and 0.2g pmn550 catalyst. utilizing pyrex glass air bubbler, dry air has been bubbled through the reaction mix at a 150 ml/min flow rate and stirred for (20,40,60,80,100,120,140) min. with constant air bubbling and temperature maintained at (20,30,50,70,80,90,120)°c. following oxidation, the sample has been mixed with an equal extraction solution volume (20:80 methanol/distilled water) and transferred into separating funnel, where oil layer has been separated. to achieve maximum sulfur removal, the temperature of the reaction and the time have been enhanced. the reactivity regarding various sulfur compounds has been studied via conducting reactions at various temperatures and withdrawing small aliquots from reaction sump at various times. the kinetics of oxidation were also investigated. hydrogen peroxide and performic acid concentrations were optimized. it was also looked into the impact of extraction number on total desulfurization yields. figure (3): experimental device of cods reactions figure (4): extraction process for different operating conditions najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 153 figure (5): product of catalytic oxidation of sulfur compounds in naphtha figure(6): catalytic oxidation product for different conditions figure(7): changing the color of raffinate due to changing operational conditions and the amount of sulfur content also varies 4.1.3. measurement of sulfur concentration by astm d7039 the sulfur concentration has been determined through sindie otg sulfur analyzer using the astm d7039 method. the sindie device provides enhanced accuracy and precision when measuring ultralow sulfur diesel and gasoline, as well as crudes and heavy fuel oil, because astm d7039 approach is optimum for refining industries, in which performance, reliability and detection are crucial. the device is located at the ministry of oil's researches and development oil centre. 4.1.4. total sulfur analyses the total sulfur concentration in the samples has been determined using sn analyzer (antek by pal) with chemi-luminescence and a vacuum ultraviolet detector. as a carrier gas, argon was used, and pure oxygen was used as an oxidant. analyses have been carried out in triplicates, with the average result indicated for every μl of injected samples. using the next relation, the desulfurization yield related to the model oil has been calculated as % desulfurization.: %𝑫𝒆𝒔𝒖𝒍𝒇𝒖𝒓𝒊𝒛𝒂𝒕𝒊𝒐𝒏 = 𝑺𝒐 −𝑺𝒕 𝑺𝒐 ×𝟏𝟎𝟎 (𝟏) where the so represents the sulfur concentration of the original heavy naphtha and st represents the treated oil’s sulfur concentration. 5. results and discussion 5.1. characterizations of the catalysts the characterization of composite supports and the prepared catalysts provides information regarding morphology, structure, and the chemical composition. the information is vital to explain the relations between their physiochemical and chemical properties as well as on the catalytic activity. 5.2. fourier transform infrared (ftir) -spectrum ftir spectra, illustrates that sharp feature appearing corresponded to hydroxyl groups of our pmn550 peak at 3400 cm-1 might be identified [28] . also, the peak at the value of 1183cm-1 is representing si-o-al and si-o-si bonds in a stretching mode. in addition, tio2 showed strong absorption peaks at 1402 & 1654cm-1, ftir bands at 780cm−1 and 1100cm−1 might be allocated to asymmetric and symmetric stretching vibration values of si–o–si linkage regarding the model of the zeolite [29][30] .the vibration modes of 1046cm−1 and 793cm−1 have been assigned to internal vibration of sio4. the h–oh bending vibrations related to molecules of water that were adsorbed have been identified at 1625cm−1. ftir spectroscopy thoroughly detects the acidic groups of the hydroxyl oh of solid catalysts [12][13]. 154 najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 figure (8): ftir-spectrum 5.3. chemical composition xrf was applied for determining the structural formula related to prepared samples. xrf analyses have indicated that natural zeolites has been majorly composed of al2 o3 (11.437%) and sio2 (45.104 %) succeeded by fe2 o3 (8.449%), cao (7.276%), mgo (4.183%), na2o (2.432%), k2o (2.18%), tio2(1.257%), mno(0.086%), and p2o5(0.851%). in existence of aqueous solutions, surface oh groups were developed on such oxide types. results have exhibited that 0.270mmol/g surface oh groups have been present on pmn550 catalyst surface. oh groups that have been formed on the surfaces of the metal oxide have played the role of brnsted acid sites 𝑀𝑒𝑂𝐻 +𝐻+ ⇋ 𝑀𝑒𝑂𝐻+ (1) 𝑀𝑒𝑂𝐻 +𝑂𝐻− ⇋ 𝑀𝑒𝑂− +𝐻2 𝑂 (2) in which, me oh2+, me oh, and meo− are representing the protonated, neutral, and de-protonated surface oh groups. 5.4. x-ray diffraction (xrd) xrd has been defined as the major analytical method that is. figure (9): xrd diagram figure ( 10): afm particle size distribution with average diameter used to determine the grain size, phase composition, and crystal structures of materials. based on pigments’ distribution, the material composition might be analyzed (qualitatively) through comparing the powder diffraction. in addition, the catalysts’ xrd analysis was conducted at the temperature of the room within a range of bragg angle 10 o ≤ 2θ≤ 90o at 2°min-1 scanning speed via x-ray diffract meter, with the use of cu k αradiation (λ=3.44690 a°). the results indicates that the main pmn550 sample phases have been anorthite, albite, and hematite. pmn550 catalyst exhibited many patterns of xrd. 5.5. pore volume and surface area analyses the pore volume and surface area have been measured for prepared pmn550. table 2 shows the pore volume, surface area, and pore sizes of synthesized pmn550. it may as well be observed that after calcination, surface area and pore volume have been slightly decreased because of the occupation regarding active component in certain spaces within samples. the micrographs showed that the particles of the catalyst had higher agglomeration, while individual granules corroded and rough surfaces that which might be because of particles’ attrition throughout reaction and the reacting materials’ settling on the surface of the catalyst. table(2): summary of pore volume, surface area, and pore size of pmn550 catalyst catalyst surface area (m2/gm) pore size (nm) pore volume (cm3/gm) pmn550 0.4703 12.71315 0.001495 6. (cods) of heavy naphtha the effect of the operational parameters on the efficiency of the catalytic process and desulfurization was studied. through reactor type a batch reactor, it was investigated to increase the effect of the ratio of) h2o2/hn (from) 0.1-0.6(. the results showed that the efficiency of desulfurization of hn increased when the ratio was increased. as all other variables were constant at the optimum values (ph = 1, weight of the catalyst = 0.01 g, temperature = 80 °c and time=60min). the maximum value was reached at 0.4 it was noted that increasing the volume ratio to more than 0.4 leads to a sharp decrease in the efficiency of desulfurization of hn in the presence of pmn550 and a direct increase in the efficiency of removing sulfur from hn by increasing the ratio from (0.1-0.4) specifically, and this efficiency was from (60%-65%), respectively as shown in fig. 11 the ratio of (h2o2/hn) produces the hydroxyl ion (oh-) and the performance acid ch2o3, and the increase of these two leads to an increase in the oxidation efficiency of organic sulphur compounds to form a sulfate radical and adsorption over the pmn550 catalyst, decomposing hydrogen peroxide to the hydroxyl group (oh-) and a highly reactive hydroxyl radical (oh ∎ ) equation (3). sulfur compounds are attacked by the hydroxyl radical according to equation (4) haw et al. [14].haw et al. reported that hydrogen peroxide decomposes to water and gaseous oxygen, (equation (5)), it competes with the previous pathway that forms hydroxyl radicals melada et al. [15]. inhibition of the formation of hydroxyl radicals leads to inhibition desulfurization process. najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 155 this leads to poor performance of pmn550 beyond ratio (0.4) unlike pmn550, which is rich in oxygen molecules, which acts as a stabilizer for h2o2 and prevents its decomposition to h2o, o2 [15]. it is not confirmed completely the role of diffusion in decreasing the desulfurization activity above the ratio of h2o2 to hn of 40%. h2o2 catalyst → oh∎+ho− (3) (r)2s+oh∎ → (r)2so → +oh∎ (r)2so2 sulfoxide sulfone (4) h2o2 → h2o+1/2o2 (5) figure (11): effects of the hydrogen h2o2 to the ratio of the heavy naphtha (h2o2/hn) on efficiency of percentage de-sulfurization at optimal conditions. fig. 12 shows that increasing the dose of formic acid to heavy naphtha (h2o2/hn) leads to a decrease in the desulfurization process at a rate higher than 15%, while the initial optimum conditions are, (ch2o2/hn = 0.15, catalyst weight = 0.01 g, temperature = 80 °c , time = 60 minutes). due to the low acidity of the solution ph and, as a consequence, the efficiency of the catalytic oxidation process for desulfurization was negatively affected. formic acid reacts with hydrogen peroxide to produce performic acid (ch2o3), which has a major role in the catalytic oxidation process of desulfurization yu et al. [16]. the efficiency of the catalytic oxidation process of removing sulfur decreases if the dose of formic acid is more than 3 ml and this is due to three things [16]. the first is that the thermal adsorption of organosulfur compounds on the surface of pmn550 decreases, and their ability to collide with the active sites of oxygen also decreases. second, it is possible to push free radicals from hydroxyl oh generated from h2o2 on the surface of carbon. finally, pmn550 has strong affinity with hn, and can be easily fractionated. pmn550 acts as a phase transfer agent between the formed performance acid and refractory organosulfur compounds as a very effective pathway in the catalytic oxidation process for the removal of refractory organosulfur compounds. figure ( 12 ): effects of the ph of the solution on the efficiency of the percentage de-sulfurization at the optimal conditions. fig.13.increasing of pmn550 catalyst under optimal conditions. (h2o2/hn=0.4, ch2o3=0.15, ph=1,t=80co, time=60min). leads to an increasing of the surface area,thus increasing the efficiency of the catalytic oxidation process to remove organic sulfur compounds (cods). figure (13): effects of the catalyst weight upon the efficiency of the percentage de-sulfurization at the optimal conditions. increasing the temperature from (12-20) °c at the optimal conditions for the rest of the variables. (h2o2/hn) =0.4, (ch2o2/hn) =0.15, ph=1and time=60min. increasing the efficiency of the catalytic oxidation process to remove the organic sulfur compounds from the heavy naphtha product. as shown in fig. 14 this is due to the production of large quantities of active oxygen and the oxidation of the organic sulfur compounds at high temperatures. this is to accelerate the reaction with these compounds when the temperature rises from (20-90) °c . also, increasing the temperature reduces the viscosity of the solution [17]. thus, it facilitates the penetration of the solution into the pores of the catalyst pmn550, and 156 najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 thus spreads on the outer and inner surfaces (external and internal diffusion) inside the pores of the catalyst zeolite (pmn550). thus, it enhances the efficiency of the catalytic oxidative process of the reaction of organic sulfur compounds. forming sulfonates and sulfoxides that are separated, by the extraction process. increasing the temperature to above (90°c) did not result in any increase in the efficiency of the process, making(90 °c ) the best thermal temperature in economic terms. raising the temperature above (90 °c ) useless. figure (14): effects of the temperature on the efficiency of the percentage desulfurization at the optimal conditions. the residence time inside the reactor mainly affects the efficiency of the catalytic oxidation process of sulfur desulfurization through the decomposition of organic sulfur compounds in the optimal conditions for the process. (h2o2/hn) =0.4, (ch2o2/hn) =0.15, ph=1, t=90°cand time=60min as noted in fig. 15. in addition, increasing the residence time increases the adsorption of organic sulfur compounds on the surface of the catalyst and between the internal pores, for pmn550, which increases the adsorption efficiency srivastava et al. [18].no change in the efficiency of the process was observed when the residence time was increased to more than 60 minutes. the reason is due to the presence of a semi-equilibrium state. perhaps the presence of many vacant active sites on the surface and inside the catalyst in the first 60 minutes. after that, no more adsorption occurred due to the saturation of these sites [18]. regeneration of catalysts must be carried out in order for these catalysts are reused again after being saturated with organic sulfur compounds. in the present work, reactivation of pmn550 is inexpensive although pmn550 catalyst was used, more than once after its use in the process of oxidation and saturation with sulfur compounds and without reactivation and gave high results. figure (15): effects of the time of the contact on the efficiency of the percentage de-sulfurization at optimal conditions. 6.1. effect of types of organic acid on the oxidative desulphurization of heavy naphtha in fig. 16, the effect of different acids on the catalytic oxidation process was studied in the presence of hydrogen peroxide to react with it to form performance acid. the maximum removal process was with sulfuric and formic acids at the beginning of the tests, where the removal rates were 50% and 55%, respectively. whereas, other acids such as glacial acetic acid, malic acid and acid phthalates. the percentage of organic sulfur compounds removed was 47%, 45% and 40%, respectively. previous research indicated that these oxidants have a high selectivity for the oxidation of organic sulfur compounds. [17-19]. sulfur compounds that predominate mainly thiophene, alkylthiophene and benzo thiophene (bzt) song et al. [20]low molecular weight thiophenes are easily oxidized by these oxidants compared to complex polycyclic thiophenes ali et al. [19]. figure (16): % desulphurization of heavy naphtha with organic oxidants. oxidation mechanism of formic acid with hydrogen peroxide and the presence of a donated proton. formic acid is a strong acid. non-selective oxidation undergone by phthalic acid. it oxidizes other functional groups, other than sulfur moieties, such as hydrocarbons, elevated olefins. its formation associated with resonance-stable benzoate ions is the reason for this. malic acid also has to be very weak because the anion (maleate ion) najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 157 formed is stabilized by the double bond and the carbonyl effect of the groups ... thus, instead of being used by oxidation, the formed anion will react with a proton to form an acid. figure (17): oxidation mechanism with h2o2 in presence of a proton. as a result, in the order sulfides, disulfides > benzothiophenes > thiophenes, the reactivities of oxidation of organosulfur compounds have been decreased. the oxidation reactivities related to thiophenes and benzothiophenes were increased by methyl substituents, most likely because of the increase in the electron density on atom of sulfur otsuki et al. [23]. sulfuric acid catalyzed oxidation with h2o2 yazul et al. [22].showed a similar reactivity trend [19]. the organosulfur components have been smoothly oxidized with h2o2 with the existence of hcooh in this work, resulting in the formation of peracetic acid. as a result, oxidative treatment will be beneficial for naphtha's ods. hds also serves as an effective pretreatment for ods by removing thiophenes that are resistant to oxidations, which is why, the sequential ods and hds treatments for the ultra-deep de-sulfurization of heavy naphtha should be effective. 6.2. effect of extraction on the oxidized model oil (heavy naphtha) the polar solvents were utilized in order to extract oxidized oil, in the process of the ods. in this research, the solution of the methanol water (80: 20) has been utilized to extract the model oil that has been oxidized in presence of the pmn 550. for the purpose of investigating the solution of methanol water (80: 20) extraction efficiency, extracted sulfur compounds’ concentration has been researched. the sulfur concentration balance in the extract of the heavy naphtha, following catalytic oxidation, has been illustrated in fig. 18. data has revealed that the model s compounds might be extracted slightly by solution of the methanol water with the oxidization of heavy naphtha. on the other hand, in the cases of the catalytic oxidation that is followed by heavy naphtha extraction, about 90% of s has been eliminated. throughout the step of the extraction, all compounds of oxidized sulfur have been shifted to the solution of the methanol water. the results that have been listed in table 3 have shown that the desulfurization yield of 1st, 2nd,3nd and 4rd extraction stage was 90, 92,95 and 99%. it has been observed from results that following the 2nd extraction did not show sever changes in the efficiency of the desulfurization, which suggests that the extractions in 4 stages have been helpful in the maximal oxidized sulfur compounds’ removal. due to the high solvent system polarity, the heavy naphtha recovery yield has been very good, approximately 98% 99%, the minor yield loss could be resulting from the handling throughout the process of the extraction. table 3. desulfurization extraction cycles. extraction cycles conversion % sulfur content (ppm) 1 90 64.83 2 92 51.804 3 95 32.265 4 99 8.07 figure (18): desulfurization of heavy naphtha in presence of the pmn550 catalyst with several extractions with the methanol-water 7. sulfur adsorption kinetic study sulfur adsorption kinetics on the pmn550 have been investigated in order to determine best-fitting order of the adsorption. the correlation coefficient (r 2 ) have been used to compare the experimental data to the predicted model, and the (r 2 ) value closest to unit has indicated the correct model for adequately describing kinetics. in addition, the ln (qe qt) curve as a time function t fig. 19. the kinetic equation was used for the lagergren’s pseudo first order [24]. 𝒍𝒐𝒈(𝒒𝒆 −𝒒𝒕) = 𝒍𝒐𝒈(𝒒𝒆)−𝒌𝟏 𝒕 𝟐.𝟑𝟎𝟑 (2) table 4. experimental data wight of catalyst (gm) 0.2 amount heavy naphtha feed stock( ml) 20 amount hydrogen peroxide (ml) 8 amount formic acid (ml) 3 temperature °c 90 time contact(mint) 60 sulfur content (ppm) 64.83 conversion% 90 amount if adsorption (mg/g) 0.009090285 158 najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 table 5. kinetic calculation of pseudo first order intercept 0.003850579 slope -1.47822e-05 qe experimental(mg/gm) 0.009090285 qe thermotical(mg/gm) 1.008905707 k1 3.40434e-05 r2 0.3104 figure (19): time versus log (qe-qt) pseudo 1st order kinetic in this condition, fig. 20 provides a linear correlation that allow computing qe from slope and k2 to ordinate to the originally. table 6 is used to group the secondorder constants. pseudo second-order kinetic used in calculation ho et al. [25]. 𝒕 𝒒𝒕 = 𝟏 𝒒𝒆 𝟐 ∗𝑲𝟐 + 𝟏 𝒒𝒆 .𝒕 (𝟑) table 6. pseudo second-order kinetic calculation ce time(min) qt t/qt ce 0.039048 20 0.00404271 4947.176523 0.039048 0.026022 40 0.00606174 6598.765371 0.026022 0.0162525 60 0.007576013 7919.733501 0.0162525 0.019509 80 0.007071255 11313.40901 0.019509 0.0208116 100 0.006869352 14557.41386 0.0208116 0.0214629 120 0.006768401 17729.4473 0.0214629 0.0227655 140 0.006566498 21320.3462 0.0227655 figure (20): pseudo second-order relation the benefit of utilizing such model is that there’s no requirement for knowing the equilibrium’ capacity from experiments, as it might be specified from the model via attempting firstand second-order, it can be noted that the second-order showed more accuracy (r 2 =0.9781) compared to the first-order r 2 =0.342. table 7. kinetic calculation of pseudo second order intercept 909.6769305 slope 139.3188451 qe experimental(mg/gm) 0.009090285 qe thermotical(mg/gm) 00717778 k2 5.66361e-08 r 2 0.9781 8. study of adsorption isotherms isotherms were investigated in order to better understand the adsorption phenomenon, such isotherms were determined using a catalyst, a batch process in naphtha solution of 20 ml, and an initial sulfur concentration of 651.3ppm. the solution has been kept shacked to ensure that sulfur is distributed uniformly over the solution. for specific temperatures of ° c, the sulfur concentration in the solution has been monitored as a time function. furthermore, the concentration of the equilibrium has been determined, and the amount of the sulfur that has been adsorbed on catalyst has been assessed using the formula: qe = (c o – c e) *v/m (4) where: qe: represents amount of sulfur that is being adsorbed on the equilibrium pmn550 (mg/g), c o: represents the sulfur’s initial concentration in the solution (mg/l), m: represents the catalyst mass(g), c e: represents the sulfur concentration in the solution at the equilibrium (mg/l), v: represents the solution’s volume (l). 8.1. freundlich isotherm the freundlich model, which indicates heterogeneity at the adsorbent's surface, has been used to calculate the adsorption capacity using the next formula: 𝑸𝒆 = 𝑲𝒇.𝑪𝒆 𝟏 𝒏 (5) where q e represents the amount of metal adsorbed per gram of adsorbent at equilibrium (mg/g). k f constant of freundlich isotherm (mg/g) n represents the adsorption intensity; ce represents the equilibrium concentration of the adsorbent (mg/l) the freundlich equation in logarithmic form according to the relationship: 𝒍𝒐𝒈𝑸𝒆 = 𝒍𝒐𝒈𝑲𝒇 + 𝟏 𝒏 𝒍𝒐𝒈𝑪𝒆 (6) the experimental results obtained for isotherms given in fig. 21 y = 139.32x + 909.68 r² = 0.9781 0 5000 10000 15000 20000 25000 0 50 100 150 psedo scond order time(min) ) t/ q t y = -1e-05x + 0.0039 r² = 0.3104 0 0.002 0.004 0.006 0 50 100 150 lo g (q e -q t) time(min) psedo 1st order najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 159 y = 0.0175x + 0.0448 r² = 0.9963 0 0.002 0.004 0.006 0.008 0.01 -2.25 -2.2 -2.15 -2.1 -2.05 -2 lo g q e logce frendlich isotherm y = -0.3502x + 160.82 r² = 0.7858 0 50 100 150 200 0 50 100 150 200 q e -1 ce-1 langmuir isotherm figure (21): freundlich isotherm for adsorption at all catalyst loading table 8. the experimental results freundlich isotherm the curve showing the isotherms in fig. 21 indicates that adsorption is following the model of freundlich, that experimental results could be correlated using freundlich eq., and that the coefficients of the correlation have been near the unity. the isotherms were used to calculate the freundlich constants k and n. 8.2. langmuir isotherm langmuir model can be used if a monolayer has been adsorbed and if the adsorbed molecules interact. based on the next relationship, the langmuir’s eq. is applied for just 1 mono-layer that is being adsorbed with well-defined number of the identical and uniform adsorption sites: 𝒒𝒆 = 𝑸𝒐.𝑲𝑳.𝑪𝒆 (𝟏+𝑲𝑳.𝑪𝒆) (𝟕) c e represents the concentration of equilibrium of adsorbate (mg/l), qe represents the adsorbed metal amount for each gram of adsorbent at the equilibrium (mg/g). qo represents the maximal capacity of the monolayer coverage (mg/g) k l represents the langmuir isotherm constant (l/mg). langmuir’s eq. might be represented as: through the representation of experiment results, based on langmuir’s equation gives isotherms of fig. 22. figure (22): langmuir’s isotherm for the adsorptions at all of the catalyst loadings table 9. the experimental results langmuir isotherm intercept 160.8222984 slope -0.350242525 qe experimental(mg/gm) 0.009090285 qe thermotical(mg/gm) 0.00747 kl -459.1741063 rl -0.034594882 r 2 0.7858 kl represents a constant associated with adsorption energy (langmuir’s model). r 2 value that is not more than unity is representing a favorable, meaning that the model is not favorable as well. 8.3. isotherm of temkin 𝒒𝒆 = 𝑹𝑻 𝒃 𝒍𝒏(𝑨𝑻.𝑪𝒆) (8) 𝒒𝒆 = 𝑹𝑻 𝒃 𝒍𝒏𝑨𝑻 +( 𝑹𝑻 𝒃 )𝒍𝒏𝑪𝒆 (9) 𝑩 = 𝑹𝑻 𝒃 (10) 𝒒𝒆 = 𝑩𝒍𝒏𝑨𝑻 +𝑩𝒍𝒏𝑪𝒆 (11) this isotherm has been applied as follows [26, 27]. at =temkin isotherm equilibrium binding constant (l/g), b = temkin isotherm constant, r= universal gas constant (8.314 j/mol/k), t= temperature k, b = constant that is associated with the heat of sorption (j/mol). intercept -2.598416659 slope -0.258321367 qe experimental(mg/gm) 0.009090285 qe thermotical(mg/gm) 0.007741526 kf 0.002521061 n -3.871147055 r 2 0.9963 160 najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 figure (23): temkin isotherm for all catalysts type. table 10. the experimental results temkin isotherm intercept -8.46861 slope -19.95247 qe experimental(mg/gm) 0.009090285 qe thermotical(mg/gm) 0.007618723 at 1.528732891 b -1512585.811 r 2 0.962 the qe curve vs. ln ce fig. 23 provides the ability for determining isothermal a & b constants from interception and slope. experimental results may be correlated by temkin eq. and the coefficients of the correlation are near unity, meaning that the model can represent practical data, but it is not the best of them for those catalyst pmn 550 types. temkin constant values a t & b have been determined from isotherms . table 11. the summary of the results of the isotherm . isotherm parameters pmn550 freundlich qe(mg/gm) 0.007741526 kf 0.002521061 n -3.871147055 r 2 0.9963 langmuir qe(mg/gm) 0.00747 kl -459.1741063 rl -0.034594882 r 2 0.7858 temkin qe(mg/gm) 0.007618723 at 1.528732891 b -1512585.811 r 2 0.962 table 12. the optimum condition in experimental variable unit value conversion weight of catalyst gm 0.2 99% temperature k 363 time min 60 hydrogen peroxide ml 8 formic acid ml 3 number extraction cycle 4 9. conclusions the catalytic oxidation of organic sulfur compounds using ch2o2 and h2o2 together with the pmn550 catalyst showed a high efficiency to remove the organic sulfur compounds from hn up to 99%. the initial sulfur content of a real sample of heavy naphtha ore produced in iraqi refineries / doura refinery = 651.3ppm at optimum operating conditions. increasing the ratio (h2o2/hn, cho2o2/hn) promotes an increase in the efficiency of the process of removing organic sulfur compounds from hn to reach the maximum percentage of 40% and 15%, respectively, due to the formation of hydroxyl ions (oh-) and the formation of (ch2o3 )performance acid, which led to the cracking of (hn) through the formation of) so4--2 (which was adsorbed by pmn550 catalyst. pmn550 catalyst showed stability in oxidative activity after 40% enrichment of oxygen molecules, which prevents the decomposition of (h2o2) to (o-) and( h2o). the increase in (ph) resulting from formic acid is favorable for the oxidation of organic sulfur compounds. formic acid and hydrogen peroxide react to produce a performance acid (para-acid ch2o3) which accelerates the catalytic oxidation process of organic sulfur compounds. the low ph value is a suitable environment for the reaction and formation of ch2o3 acid. the surface area of pmn550 and its active sites increases with increasing amount of catalyst (a positive relationship) and this enhances the efficiency of the catalytic oxidation process (cods) of organic sulfur and desulfurization compounds. temperature is important in the catalytic oxidation process, where it removes organic sulfur compounds (cods) .increasing the temperature to (90 °c ) increases the production of active oxygen, which accelerates the oxidation reaction of organic sulfur compounds, reduces the viscosity of the solution and thus allows penetration and movement within the narrow catalytic pores to be reacted on the outer and inner surfaces within the channels. and catalytic ducts, especially for heavy fluids. increasing the residence time to 60 minutes increases the efficiency of the cods process for liquid reactants by increasing the ratio of oxygen to organic sulfur compounds. increasing the residence time to 60 minutes increases the contact between the pmn550 catalyst and the organic sulfur compounds, which enhances the efficiency of the adsorption process. the optimization technique to find the optimal (cods) process kinetic parameters with the use of 2 approaches (i.e. the linear and the nonlinear) based on experimental results can be used with higher degree of the confidence. it has been noticed that the 2nd approach (i.e. the nony = -0.002x 0.0008 r² = 0.962 0 0.002 0.004 0.006 0.008 0.01 -6 -5 -4 -3 -2 -1 0 temken isotherm q e lnce najm abed hamdan , mohammed ali mutar /al-qadisiyah journal for engineering sciences 14 (2021) 150–161 161 linear) has shown a higher degree of the accuracy according to minimization of summation of square error (sse) between the experimental and the expected results with the mae of <5% between all results at different operation conditions. the mathematical model obtained can be utilized to find the optimal operating conditions for improving the fuel quality for the purpose of obtaining free sulfur content. references 1. h.j. chang, g.l. cho, y.d. kim, the 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(2002). methods and techniques for the selective extraction and recovery of oxoanions. chemical society reviews, 31(1), 60-67. article al-qadisiyah journal for engineering sciences 15 (2022) 032–037 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)787796310 e-mail address: qabelh2010@gmail.com (qabeela q. thabit) https://doi.org/10.30772/qjes.v15i1.803 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. a new dna strand-based encryption algorithm using symmetric key generation table qabeela q. thabita*, alaa a. al-saffarb and issa ahmed abedb a directorate of education, ministry of education, basrah,iraq. b engineering technical college, southern technical university, basrah, iraq a r t i c l e i n f o article history: received 23 february 2022 received in revised form 5 april 2022 accepted may 22, 2022 keywords: dna-based cryptography encryption decryption binary code dna bases a b s t r a c t due to the characteristics of deoxyribonucleic acid dna chain which contains a very wide range of parallelism mechanism, and the computing processing speed can arrive at 1 billion times per one second. it is worth only a billionth of a traditional computer. it became the focus of the attention of researchers in the field of encryption. the aim of this study is to find an efficient and safe algorithm for data encryption as well as decryption. a symmetric novel method is proposed in this paper depends on dna encryption by applying a mixture of dna oligonucleotide and new development of algorithm technology steps. it includes encoding each character to a predefined decimal number, converting it to it s equivalent binary number and then converting it into dna coding. finally, converts each code of dna to a number that represents a row and column numbers. simulation all all text (words) is executed in parallel by using visual basic programming, obtained an excellent encoding result in terms of time because all the characters, so the algorithm is able to process the largest number of data, all of them encode at the same time. an efficient, fast and highly encoding scheme has been obtained due to the complete executing parallelism of the dnabased algorithm. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction initially, because of the great parallelization and excellent energy efficiency of deoxyribonucleic dna coding and the great density of information inherent in dna molecules for data storage and coding, it is distinguished from other coding technologies. the dna cryptography technique is a new encouraging path in cryptography science that has emerged as a result of advances in the field of dna computing, the uses of dna and rna have multiple scientific applications within the field of dna nanotechnology, as they have been used in optical computers [1,3] and in drugs that treat cancer [4], as well as their use in cryptography information because the world is witnessing an explosion of information in which the analysis of information has grown a very important mechanism source, and therefore the task of information field security is becoming increasingly important. cryptography is the most important part of telecom and computer security infrastructure [5]. research continued in the science scope that related to cryptography field and steganography field using dna in the past few years, in 2011 s. jeevidha et.al. analyzed a proposal dna computing approach with dna depends cryptographic different approaches which produces the easy concept and constraints of all works that focus on this research [6] z. yunpeng et al., on the other hand, used simulation and theoretical research to demonstrate the algorithm's efficiency, biosecurity and math security are two examples. the used algorithm has a tremendous key space, plaintext has a high sensitivity, and encryption has a huge effect. in addition, the algorithm has been verified to work at the computing processing stage in the encryption security evaluation scheme [7]. after this offered innovative algorithm to communicate data securely by a. atito et.al. in 2012. the playfair-insertion the procedure is a construction http://qu.edu.iq/ mailto:qabelh2010@gmail.com https://doi.org/10.30772/qjes.v15i1.803 http://creativecommons.org/licenses/by/4.0/ qabeela q. thabit el at. /al-qadisiyah journal for engineering sciences 15 (2021) 032–037 33 encryption and data concealment applying some features of deoxyribonucleic acid (dna) structure sequences [8]. dna cryptography applies hybridization of dna oligonucleotides, and the generic binary one-time pad methodology was mixed in this paper. [9]. digital dna encoding, rules of complementary, and biotechnological designs in this scheme [10]. using dna sequences for the encoded text message is a means of transmitting information, a process to transfer encrypted data through a secure communication channel. the time complexity of transferring encrypted messages is reduced by the message transmission process. biomolecular and one timepad technologies is done for secure message encryption [11]. an algorithm computation security using dna cryptography suggested. in wireless communication, dna cryptography is combined with a safe support layer (ssl) to create a secure channel for a more secure information replacement [12]. cascaded dna cryptography and steganography which represent hiding of data. initially it performs dna cryptography and then its hidden in a random frame of video [13]. kevin santoso et al. described a section-based dna steganalysis approach that stores binary information in non-coding regions of the nucleotide sequence. the goal of sector-based compression is to protect the organism's life data while maintaining a high level of protection, data performance, and error checking. a sector is made up of referencing bases, segmentation message bases, and parity bases [14]. dna cryptography introduced after that in many method some these traditional such as genetic algorithm [15,16] and vigenere cipher[17], data encryption standard (des), advanced encryption standard (aes), and blowfish are examples of symmetric cryptographic techniques [18], and asymmetric key cryptographic algorithms like rivest-shamir-aldeman rsa[19], but other encryption based on biological technologies such as dna chips and polymerase chain reaction pcr amplification[20-22], dna encryption dependent on dna arithmetic and biomedical processes is a strategy for encrypting dna[23]. bimolecular cryptography emerged as field for data encryption which exploiting specific biomolecular interactions as a unique approach for information security [24]. a novel algorithm to communicate data securely is suggested in this paper. the technique is a combination of encryption using properties of dna sequences and generation matrix as key for decryption process. consequentially, the presented method includes mainly of three levels. the first level, plaint text convert to binary sequences. while the second level the safe data is encrypted using a dna, and the third level, the encrypted data is hidden by convert it into matrix of number. the submitted algorithm can successfully work on any text writing that represents in decimal and then binary data since it is transformed into a string of dna nucleotides adopting the code of dna. 2. related work a summarized analysis of some associated works is discussed in this section as following: sirisha ks and sheena mathew [25] are merging cryptographic protocols and steganography techniques gave a new hybrid method that performs the device has multiple layers of authentication, including dna-based advanced encryption standard (aes) encryption. the steganalysis schemes employed do not expand the original dna sequence, and the encrypted data can be withdrawn without a real dna known sequences. in this work, the proposed encryption algorithm depends on the mixture of the conception of dna encryption and dna dependent aes dna steganography is combined with encryption. the dna-rsa hybrid cryptographic system proposed by narendren s et al [19] integrates different appropriate algorithms used in existing dna cryptography algorithms with the rsa algorithm, leading in a dna-rsa hybrid cryptographic algorithm. the hidden message is translated to dna before being passed via a rounded function. transcription, translation, mutation, reverse transcription, and circular right shift are among the activities performed by a round method. the round function's output (i.e., the dna sequence) is then translated to binary number format, with the decimal value of the binary sequence serving as the hidden message for the rsa algorithm. the cipher text fragments are then estimated using rsa, and as all the blocks are merged into a unified cipher text. this mixed cipher text is first compiled to binary numbers, then to dna. as a response, this dna sequence will be the last cipher text used during the contact. vidhya and rathi priya [26] suggested method composes from the steps as following, the first step being to apply the encryption key to the original text by encrypting it by that key, then take ascii number for each letter after that convert all decimal number into corresponding binary numbers and finally convert each pair of binary number to dna sequences. the sequence of dna can be received by the receiver. create a binary representation of the dna sequence. erase the suffix secret message afterward. binary numbers are compared to ascii numbers with an eightbit weight. the ascii numbers are transferred to ascii values, and when the shift key is held, the plaintext is viewed by the receiver. b. devi patnala and r. kiran kumar [27] offered a dna-based defense algorithm based on dna codon groups. this scheme utilizes the exchange process, in which transformations are performed using a lookup table is a collection dna codon groups and their corresponding alphabet values. this table has a random number generator and should be sent to the recipient via secure media. the main idea behind dna molecules is that they can collect information for a long period of time. d.ratna kishore et. al [28] because the key is generated at random, figuring out the plaintext is an unfathomable task for the intruder is presented. at first, both the transmitter and the recipient agree that the spiral pattern is correct. the sender's randomly generated key is sent to the receiver over the secure media. there are three levels of security in the proposed technique. xor's cross join with the plaintext and the key, i.e., xor(m1-k1), xor(m2-k2), xor(m3-k3), and xor(m4k4), is conducted at the primary level number. at the next level, the dna sequence, which is four characters long, is mapped to a dna ascii value. another dna ascii table is being constructed with the goal of distinguishing the mapping in 256! distinct ways, increasing the complexity of the intruder's actions. the dna string sequences are placed in a spiral form in the last level. the data is transmitted to the recipient in a row-byrow fashion. to provide a higher security framework, the proposed method increased the level of confusion and diffusion. anupam das et al. [29] presented a detailed report, and the information provided here will greatly assist researchers in doing further research in this area. the modules for degenerative changes, cryptography, and decryption must commission need subsequent work on cryptographic techniques deployment. the current work will also aid in the development and integration of dna-based cryptography and steganography methodologies. prasanna balaji narasingapuram and m. ponnavaikko [30] devised and implemented a novel security method to strengthen the user's level of security it's a user authentication strategy for any network or cloud application that requires it. in a protected data transfer application, the user authentication procedure is one of the most critical and vital activities. it certifies if the user is acceptable or malevolent, and whether the user has access to the information. 3. proposed algorithm the suggested system produces a secure key as matrix in new manner which increases difficulty to break the code of plaint text. suggested a new encryption approach is implemented depended on three levels to get the cipher text. the entire operation of dna encoding, and decryption illustrated in the following fig. 1. 34 qabeela q. thabit el at. /al-qadisiyah journal for engineering sciences 15 (2022) 032–037 figure 1. dna encryption & decryption algorithm based on key generation 3.1. algorithm for encryption level one: the encryption procedure is viewed in the following stages as: 1: input data (plaint-text) separates into n-words (number of words), each one encrypted by converting it into a corresponding number (decimal form) for each character by using table 1 [31]. 2: and all decimal values are subtracting from 25 at the same time. 3: take the results from step2 and convert into character and a corresponding number also from table 1. 4: convert these number into form binary code (0’s with 1’s). table 1. decimal number for each character letter code no. letter code no. ‘a’ 0 ‘n’ 13 ‘b’ 1 ‘o’ 14 ‘c’ 2 ‘p’ 15 ‘d’ 3 ‘q’ 16 ‘e’ 4 ‘r’ 17 ‘f’ 5 ‘s’ 18 ‘g’ 6 ‘t’ 19 ‘h’ 7 ‘u’ 20 ‘i’ 8 ‘v’ 21 ‘j’ 9 ‘w’ 22 ‘k’ 10 ‘x’ 23 ‘l’ 11 ‘y’ 24 ‘m’ 12 ‘z’ 25 level two: 1: add padded zero in front all binary numbers, and each block 6bit in binary, considered as blocks. 2: after that, through using (2) bit binary coding law, every 2 bit is convertible to nucleotide bases (dna bases). [28] as shown in table2, we get n-strings of dna bases sequences. table 2. dna code binary number dna code 00 a or (adenine) 01 c or (cytosine) 10 g or (guanine) 11 t or (thymine) level three (key generation): 1: delete the padded zero in front all binary numbers. 2: convert all binary numbers into decimal numbers. 3: each number results from step 4 subtract from 25 and convert the result number into character by using table 1. the design of the key table is done based on the process of entering the nitrogenous bases associated with a specific character. the table consists of three rows for each code belonging to a character where the first line represents the first base, so if the first base is adenine a that is placed in the first column and if the first base is cytosine c it is placed in the second column, but if the base guanine g placed in the third column and placed in the fourth column if they are thymine t. and so on for the rest character codes as explain in table 3. therefore, the last form of cipher text as matrix all elements are two digits first is number that represent of row and the second is represented number of columns related to nitrogen base in each character code. 3.2. algorithm for decryption analysis all number to corresponding nitrogen bases for each character code. convert the character code to binary code according table2. delete the padded zero in front all binary numbers. convert all binary numbers into decimal numbers each number results from step 4 subtract from 25 and convert the result number into character by using table 1. encryption procedure is a numerical description representation as the following example: input data using is "symmetric algorithm", the operation steps is explained as following table 3: table 3. two-level encryption level one level two s 18 25-18 7 h 00111 00111ø 00-11-10 atg y 24 25-24 1 b 00001 00001ø 00-00-10 aag m 12 25-12 13 n 01101 01101ø 01-10-10 cgg m 12 25-12 13 n 01101 01101ø 01-10-10 cgg e 4 25-4 21 v 10101 10101ø 10-10-10 ggg t 19 25-19 6 g 00110 00110ø 00-11-00 ata r 17 25-17 8 i 01000 01000ø 01-00-00 caa i 8 25-8 17 r 10001 10001ø 10-00-10 gag c 2 25-2 23 x 10111 10111ø 10-11-10 gtg a 0 25-0 25 z 11001 11001ø 11-00-10 tag l 11 25-11 14 o 01110 01110ø 01-11-00 cta g 6 25-6 19 t 10011 10011ø 10-01-10 gcg o 14 25-14 11 l 01011 01011ø 01-01-10 ccg r 17 25-17 8 i 01000 01000ø 01-00-00 caa i 8 25-8 17 r 10001 10001ø 10-00-10 gag t 19 25-19 6 g 00110 00110ø 00-11-00 ata h 7 25-7 18 s 10010 10010ø 10-01-00 gca m 12 25-12 13 n 01101 01101ø 01-10-10 cgg level three: after reaching a sequence of three nitrogen bases representing each letter in the second level of coding, we distribute those bases on a table in a way that each sequence is built of three rows in each column from four columns, three bars representing the number of nitrogen bases for a minimum obtained from the last stage, and four columns representing all the possibilities of the bases probable nitrogenous be any resulting sequence (a, c, g, t). the encrypted words are taken at the same time and the rules are entered into a table where we notice for each rule three lines for each word. the a was placed in the first row of the a column of the first word while t was placed in the second row of the t column of the first word and the base g was placed in the third row of the first word's g column, and so on for the rest. we put each nitrogen base in its place based on table 4. qabeela q. thabit el at. /al-qadisiyah journal for engineering sciences 15 (2021) 032–037 35 table 5. three level encryptions first word cipher text second word cipher text 11 24 33 143 14 21 33 413 11 21 33 113 12 24 31 241 12 23 33 233 13 22 33 323 12 23 33 233 12 22 33 223 13 23 33 333 12 21 31 211 11 24 31 141 13 21 33 313 12 21 31 211 11 24 31 141 13 21 33 313 13 22 31 321 13 24 33 343 12 23 33 233 table 6. decryption operation. ch no. cipher text step1 step2 step3 step4 step5 r1 r2 r3 dna code binary code delete padded zero deci. no. original character number o ri g in a l c h a ra c te r 1 143 11 24 33 atg 001110 00111 7 18 s 2 113 11 21 33 aag 000010 00001 1 24 y 3 233 12 23 33 cgg 011010 01101 13 12 m 4 233 12 23 33 cgg 011010 01101 13 12 m 5 333 13 23 33 ggg 101010 10101 21 4 e 6 141 11 24 31 ata 001100 00110 6 19 t 7 211 12 21 31 caa 010000 01000 8 17 r 8 313 13 21 33 gag 100010 10001 17 8 i 9 343 13 24 33 gtg 101110 10111 23 2 c 1 413 14 21 33 tag 110010 11001 25 0 a 2 241 12 24 31 cta 011100 01110 14 11 l 3 323 13 22 33 gcg 100110 10011 19 6 g 4 223 12 22 33 ccg 010110 01011 11 14 o 5 211 12 21 31 caa 010000 01000 8 17 r 6 313 13 21 33 gag 100010 10001 17 8 i 7 141 11 24 31 ata 001100 00110 6 19 t 8 321 13 22 31 gca 100100 10010 18 7 h 9 233 12 23 33 cgg 011010 01101 13 12 m table 4. level three (key generation) character no. c.a word1 c.a word2 c.c word1 c.c word2 c.g word1 c.g word2 c.t word1 c.t word2 1 a a g g t t 2 a a a c g t 3 c c g g g g 4 c c c g g g 5 a a c g g g 6 a a a g g t 7 a a a a c t 8 a a c g g g 9 c g g g g t 36 qabeela q. thabit el at. /al-qadisiyah journal for engineering sciences 15 (2022) 032–037 figure 2. simulation part of encryption process figure 3. simulation part of decryption process from table 4, we take a two number, the first represent the number of rows, and the second number of columns, after that delete all numbers represent row number and get the following n-array, in each one the number of columns represents the number of characters in each word as shown in table 5 which represent cipher text. decryption: analysis of all numbers to corresponding nitrogen bases for each character code. then convert the character code to binary code according to table2. after that delete the padded zero in front of all binary numbers, next step is converting all binary numbers into decimal numbers. finally, each number results from step 4 subtract from 25, and convert the resulting number into character by using table 1. back each number in cipher text to row number, then retrieve to nitrogen base equivalent to pair number, after that convert it into binary code as table 5. 4. discussion and simulation results in most of the research like this work, it goes through almost the same procedures, which is to convert the data into an ascii code, then into a binary digital system, and finally get the code represented by a series of nitrogenous bases, or convert each number to a specific amino acid, and thus the encoding and decoding path is known in advance. as for the proposed work, there was a change in the encryption and decryption procedures, which is a departure from the norm by implementing the mentioned steps. this added advantages to the work where the path is safe for decryption. also, relying on a table that can be read and written in an accurate manner recognized by the sender and the recipient, and provided a level of sobriety for the algorithm, in addition to that. it is possible to implement in a parallel way a full text and not just words, making a change in the efficiency of obtaining the largest amount of secure information. the implementation of the algorithm for encoding and decoding is by an easy and parallel mechanism, which supports an efficient system capable of executing an unlimited number of words. in this paper, we take an example consisting of two words as shown in fig. 2, simulation part of encryption process for plaint text “symmetric algorithm”. while fig. 3, is shown simulation part of decryption process. 5. conclusion in recent years, many papers have focused on research into dna encoding. dna encoding has a huge data capacity in addition to the possibility of parallel implementation of represent and giving a high confidentiality of data that made it the focus of attention of researchers. in this work, we presented a model for an algorithm consisting of two dimensions: the first dimension is data encryption, which includes three levels, respectively, while the other dimension is decryption, 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[31] alharith a. abdullah, rifaat khalaf, and mustafa riza, a realizable quantum three-pass protocol authentication based on hill-cipher algorithm, hindawi publishing corporation (mathematical problems in engineering), 2015 (2015) 1-6. https://ieeexplore.ieee.org/xpl/conhome/8526361/proceeding https://ieeexplore.ieee.org/xpl/conhome/8526361/proceeding article al-qadisiyah journalfor engineering sciences13 (2020) 013–021 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: azhaarazhaar17@gmail.com (azhaar jabbar) https://doi.org/10.30772/qjes.v13i1.622 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. comparative study for adsorption of acidic and basic dyes on activated carbon prepared from date stone by different activation agent azhaar radhi jabbar a*, abbas kalaf mohammad a a faculty of engineering – university of al-qadisiyah-iraq. a r t i c l e i n f o article history: received 26 november 2019 received in revised form 02 january 2020 accepted 23 january 2020 keywords: date stone chemical activation adsorption acidic and basic dyes a b s t r a c t this research includes a lab scale work to investigate the feasibility of treating waste water which is polluted with dyes exhausted from textile factory by using the adsorption process. three types of activated carbon were prepared using locally available waste material (date stone). chemical activation method with (zinc chloride, potassium hydroxide, or phosphoric acid) is used to prepare carbon. firstly, the materials were carbonized at 275o c for 90 min, and then the carbonized materials were treated with (4 molar) solution of acid, base, or salt for 24 hours. finally, these materials were activated at 600o c for two hours in the presence of nitrogen gas flow. the resulted activated carbons were checked by its (bet) surface area analysis and surface morphology by sem. the surface area values were (815, 950,600) m2/g for carbon produced from the activation of date stone by phosphoric acid, potassium hydroxide, or zinc chloride respectively. sem characterizations show that activated carbons that prepared from potassium hydroxide have higher surface area and good adsorption characteristics than that prepared from activation with phosphoric acid or zinc chloride. the adsorption process was carried out using two types of dyes. the first one is acidic (methyl orange) and the other is basic (bismark brown). the adsorption isotherms and kinetics were investigated for both dyes at temperatures (30, 40, 50, 60) o c for concentration range equal to (6-16) mg/l. the adsorption data of equilibrium were presented by using two common adsorption isotherm equations. the data was fitted fairly well with langmuir isotherm for both dyes on all types of prepared activated carbons. the kinetics of adsorption was studied by using two kinetic equations, pseudo first order and pseudo second order. the results showed a rapid increase in the rate of adsorption at the initial until equilibrium achieved. the pseudo second order model represented the data very well with confidence level 0.99. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction environmental pollution control has been a concerning issue in many countries, especially air and water pollution [1]. waste effluent from the textile industry can be problematic due to the presence of dyes in the final effluent. removal of dyes from textile effluents that is toxic and very dangerous for human beings is a major problem, because of the difficulty of treating these dyes by conventional waste water treatment methods such as coagulation , chemical oxidation , membrane filtration ,solvent extraction ,chemical precipitation ,osmosis ,….etc. these methods have not been very successful since dye is stable to light, oxidizing agent, high capital cost and operational cost or secondary sludge disposal problems. all of these problems made the scientists look for cheaper and more effective means and reach to the adsorption technology on activated carbon http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 14 azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 [2]. activated carbon is widely used on an industrial scale as an adsorbent mainly in the purification /separation of liquids and gases and also as a catalyst and catalyst support [3]. activated carbon is a carbonaceous material with a highly porous structure and large internal surface area. it can be prepared from the processing of lignocellulosic raw materials under high temperatures. any cheap material with a high carbon content and low in organics can be used as a raw material for the production of activated carbon. literature review indicates that there were many attempts to obtain low cost activated carbon from agricultural wastes such as wood [4], peat [5], nutshells [6], [7], or rice husk [8]. in this work, date stone is investigated as an alternative low-cost precursor to prepare activated carbon using koh ,h3po4, and zncl2 as activation agent for the removal of methyl orange (acid dye) and bismark brown (basic dye) from aqueous solutions. the study also includes equilibrium adsorption isotherms and kinetics, which could provide useful information and insight in the further operation and design fields. figure 1. photographic image for raw date powder before and after activation 2. experimental work 2.1. materials nitrogen (supplied from al-diwaniyah north factory, iraq) of purity greater than 95% is used as an inert gas medium during the activation process. phosphoric acid (aldrich, germany), zinc chloride (aldrich, germany), and potassium hydroxide (alpha chemika, india) with purity greater than 99% are used as chemical reagents. aqueous stock solutions of methyl orange and bismark brown were prepared by dissolving methyl orange (c14h14n3nao3s, mw: 327 gm/mol, sigma-aldrich) and bismark brown (c11h10n8, mw: 419 gm/mol, sigma-aldrich) in distilled water. 2.2. preparation of date stone activated carbon date stone waste is collected from local farms at al-diwaniyah city, south of iraq. it was washed thoroughly with distilled water then it was dried for thirty days under direct sunlight to ensure vaporization of all water and volatile materials. next, one kilogram of previously dried waste material (date stone) was grinded using an electrical grinder (jiqi, generic co., china) for about 30 minutes. the produced powder was screened for 600 micrometers using a screening analysis apparatus (gilson company). a schematic diagram illustrating the experimental setup of the activated carbon preparation system is shown in fig. 2 and 3. the reactor was made from a piece of 6-inch carbon steel pipe with 15 cm length. the two ends of the pipe piece were enclosed by two 7 inch carbon steel plates. the bottom end was welded while the upper end was fitted using two screws to enable us of changing raw materials inside the reactor. the reactor was put inside an electric furnace (hysc co., model: mf-12, china) equipped with input and output points. the nitrogen gas from the cylinders was passed through a pressure regulator and falling ball manometer equipped with suitable value to control the measurement of the pressure and flow rate of nitrogen gas. then, the n2 gas flows through (1/4) inch stainless steel pipe which was partly coiled around the reactor to ensure adequate preheating of the gas before entering the reactor. the effluent n2 gas pipe from the top of the reactor was connected with a thermocouple and temperature recorder. figure 2. a schematic diagram for the activation system figure 3. photographic image of activation system nomenclature bet brunauer–emmett–teller (surface area) ql: the langmuir maximum uptake of methyl orange and bismark brown per unit mass of adsorbent (mg/g) c0 initial concentration of dye mg/l c1 the concentration of the stock solution qe absorbance amount (mg/g) c2 the second concentration after dilution v solution volume l ce equilibrium concentration mg/l v1 volume from the stock solution. kf: the adsorption or distribution coefficient v2 volume of the distilled water required for dilution n: indication of the favourableness of the adsorption process w weight of the adsorbent azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 15 (40 gm) of date stone powder was put in a graphite crucible and covered with mineral wool in order to prevent the powdered material from being conveyed with n2 gas during burning. then, the crucible was put inside the reactor which is positioned in the furnace. the nitrogen gas was allowed to flow at a rate of (4 l/min). the sample was pre-carbonized by setting the temperature of the furnace at 275o c for 90 min. the resulted char was allowed to cool at room temperature, then it was soaked with (4m) solution of phosphoric acid, potassium hydroxide, or zinc chloride for 24 hrs. then the sample was filtrated using vacuum filtration apparatus and dried for 2 hours at room temperature. the filtrate was put in the graphite crucible inside the reactor for activation. the temperature of the reactor was set at 600oc and the nitrogen gas flow rate at 4 l/min for two hours. the produced activated carbon was allowed to cool at room temperature under nitrogen. then, it was washed with distilled water several times until the rinsed water ph equal to 6 and finally it was dried at 105 c for 6 hours in a hot air oven. after that the prepared activated carbon samples were analyzed via sem, surface area for morphology. 2.3. adsorption the dyes solutions were prepared by dissolving (0.05) gm of each dye in 1 liter distilled water. in order to prepare standard solutions with defined concentrations, the previously prepared solutions were diluted with a suitable volume of distilled water according to the law of dilution. five solutions of standard concentrations for each dye were prepared for the processing, and used them to determine the characteristics of adsorption isotherms and kinetics. c1 *v1 = c2 * v2 (1) equilibrium information, usually known as adsorption isotherms, explains how the adsorbate responds with adsorbents, and show an overall description of the nature of the interaction. it is important to optimize the design of an adsorption system [9]. the parameters gained from the various models supply valuable data on the surface characteristic of the adsorbent and its affinity for the adsorbate. langmuire and freundlich isotherm equations have been used for such analysis in this work. the adsorption isotherms for methyl orange and bismark brown on the different kinds of prepared activated carbons were examined at (30,40,50 and 60) o c where (10) ml of dye solution at specified concentration was mixed with (0.05) gm of activated carbon in a graduated test tube. then, the tube was put in a constant temperature water bath. firstly, the equilibrium time was estimated by taking samples from each test tube at different time duration. the equilibrium time is defined here as the time at which negligible concentration change is noticed within a one-half hour period. secondly, the adsorption equilibrium isotherms were examined by mixing different concentrations of dyes solutions (6, 8, 10, 12, 14, 16) ppm with 0.05 gm of each kind of prepared activated carbons. the mixture is allowed to reach equilibrium time in a constant temperature water bath. at the end of the process, samples were taken for analysis. amount of dyes that were adsorbed can be measured from the following law: 𝒒𝒆 = (𝑪𝟎−𝑪𝒆).𝑽 𝑾 (2) finally, the adsorption kinetics were investigated in a procedure similar to that of equilibrium but the samples were taken at different times until the final sample was taken at equilibrium attending. 3. results and discussion 3.1. characterization of activated carbon the improvement of surface properties for activated carbon means improvement of adsorption efficiency since adsorption process is a surface phenomena, therefore surface morphology measurements are carried out on the prepared activated carbon samples using scanning electron microscopy (sem, fei co., model: inspect s50, netherlands), bet surface area (asap2020, micromeritics, usa). 3.1.1. effect or raw material raw material properties and characteristics have a major importance since its content of violet matter and fibers determines the quantity of produced activated carbon. fig. 4 shows the sem morphology for date powder waste raw material. the sem graph confirms the formation of micro-pore on the raw materials, but with significant differences in the pore size, shape and diameter. figure 4. sem image of date stone powder 3.1.2. effect of carbonization process tars and low vapour pressure materials vaporize and cellulose matters burn out through carbonization process due to high temperature treatment, so the surface area of carboneous structure is available for adsorption of adsorbable solutes. fig. 5 illustrates an sem picture for date stone after the carbonization process. it is clearly shown that the carbonization treatment makes the raw material more amorphous and porous but with different extents. carbonized date stone has more porous structure with a random arrangement of different sizes of a pore. also, it could be recognized that carbonized material have conglomerates of carboneous matter that could be transmitted to more porous by activation by chemical agents. figure 5. sem image for carbonized date stone 16 azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 3.1.3. effect of activation process opening of enclosed pores and decreasing of conglomerates of carboneous materials are noticed through activation process due to very high temperature treatment and the effect of various chemical activation agents. figs. 6 to 8 show sem pictures for date stone after activation process via phosphoric acid, zinc chloride, and potassium hydroxide, respectively. it is clearly shown that the activation treatment makes the carbonized waste materials well developed and very porous but with identified differences due to differences in raw materials and activation agents. figure 6. sem image of activated carbon prepared from date stone by phosphoric acid activation agent figure 7. sem image of activated carbon prepared from date stone by potassium hydroxide activation agent figure 8: sem image of activated carbon prepared from date stone by zinc chloride activation agent the figures indicate that the activated carbons that prepared from date stone waste material have heterogeneous rough surface of random arrangement of cracks and cavities with low porosity. also, it could be noted from these figures that potassium hydroxide activation agents yield activated carbon with a high density of different size pores but with less uniformity of arrangement. furthermore, potassium hydroxide has the lowest impact on the environment than phosphoric acid and zinc chloride activation agents. this result agrees with the researcher [10]and [11]. this difference in the pore prise the activated carbon made from date stone with potassium hydroxide good adsorption characteristic compare with that from date stone with other activators for both acid and basic dyes. table 1 shows some properties for the prepared activated carbon. table 1. bet surface area of activated carbon activated carbon surface area m2/g pore type date +h3po4 815 micro-pore date+koh 950 micro-pore date+zncl2 600 micro-pore 3.2. equilibrium of adsorption the adsorption equilibrium isotherms give an understanding of suitability of adsorbent for a special application, and show how the amount adsorbed depends upon the equilibrium concentration of the fluid at constant temperature. the dyes concentrations and temperatures values were chosen in viewing to the expected waste water condition in the textile factory exhaust. figs. 9 to 14 show the adsorption equilibrium isotherms for adsorption of bismark brown and methyl orange at different temperatures on activated carbons prepared from date stone employing phosphoric acid, potassium hydroxide and zinc chloride as activator, respectively. these figures indicate that all curves for any specified dye (either acidic or basic) on all types of prepared activated carbons are same in nature and are of the classical adsorption isotherm type1 shape. the experimental results were fitted with the most well known adsorption isotherms that describe the adsorption of solutes from aqueous solution on to activated carbons. these isotherms called langmuir and freundlich equations. the langmuir adsorption isotherm represents adsorbate-adsorbent systems in which the range of the adsorbate coverage is excluded to one molecular layer [12]. in another words, langmuir model is used for homogeneous surfaces, while freundlich model is considered to be suitable for highly heterogeneous surfaces [12]. table 2 shows the average values of confidence level (r2) for langmuir and freundlichisotherm models for adsorption of methyl orange and bismark brown dyes on different types of prepared activated carbon. the comparison confidence level values for the two isotherm models give indication that langmuir isotherm fits the data fairly well than freundlich model. in addition, this indication could be better seen by plotting the experimental data using langmuir and freundlich adsorption isotherms in linear forms according to equation (3) and (4), respectively. the data were plotted according to equations (3) and (4) as shown in figs. 15-26. these figures clearly show that the langmuir adsorption azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 17 isotherm represent the experimental work fairly well and better than freundlich adsorption isotherm. the conclusion was that the adsorption of basic and acidic dyes on all types of activated carbon is limited to a single monolayer and all types of prepared activated carbons have homogeneous surfaces. but with different levels of homogeneity. figure 9. adsorption equilibrium isotherms for bismark brown adsorbed on activated carbon prepared from date stone using phosphoric acid as activator figure 10. adsorption equilibrium isotherms for bismark brown adsorbed on activated carbon prepared from date stone using potassuim hydroxide as activator figure 11. adsorption equilibrium isotherms for bismark brown adsorbed on activated carbon prepared from date stone using zinc chloride as activator figure 12. adsorption equilibrium isotherms for methyl orange adsorbed on activated carbon prepared from date stone using phosphoric acid as activator figure 13. adsorption equilibrium isotherms for methyl orange adsorbed on activated carbon prepared from date stone using potassium hydroxide as activator figure 14. adsorption equilibrium isotherms for methyl orange adsorbed on activated carbon prepared from date stone using zinc chloride as activator 18 azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 figure 15. langmuir adsorption isotherm for bismark brown on activated carbon prepared from date stone with phosphoric acid at different temperature figure 16. langmuir adsorption isotherm for bismark brown on activated carbon prepared from date stone with potassium hydroxide at different temperature figure 17. langmuir adsorption isotherm for bismark brown on activated carbon prepared from date stone with zinc chloride at different temperature figure 18. langmuir adsorption isotherm for methyl orange on activated carbon prepared from date stone with phosphoric acid at different temperature figure 19. langmuir adsorption isotherm for methyl orange on activated carbon prepared from date stone with potassium hydroxide at different temperature figure 20. langmuir adsorption isotherm for methyl orange on activated carbon prepared from date stone with zinc chloride at different temperature azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 19 table 2. average confidence interval levels (r2) values for langmuir and freundlich models 4. kinetic of adsorption the rates of adsorption of bimark brown and methyl orange on to different types of prepared activated carbons were presented in figs. 21 to 26 at (30,40,50or 60)o c. these figures show the rapid increase of capacity for the two dyes during the first two hours and then the low increase of capacity until equilibrium attending. the fast rate of adsorption at the initial stages may be due to the availability of the unoccupied active sites on the adsorbent and the high concentration of adsorbable solute molecules. the experimental kinetic data of bismark brown and methyl orange on activated carbons prepared from date stone and activated using phosphoric acid, potassium hydroxide or zinc chloride were correlated by two kinetics models: pseudo-first order and pseudo-second order. equations (5) and (6) represent of the two kinetics model the results show that pseudo-second order adsorption kinetic model correlates the experimental data very well. therefore, the best fit was achieved with this model equation. furthermore, the experimental data were presented in linear form by applying equations (4) and (5) of pseudo first order and pseudo–second order kinetics model equations and shown in figs. 27 to 30. also, the figures indicate that the second order kinetic model correlate the data fairly well. this interpreting that (multiple stages were included in the adsorption process. in addition, the results explain that the adsorption of bismark brown and methyl orange dyes onto activated carbons involve more than one process). figure 21. rate of adsorption of bismark brown on activated carbon prepared from date stone and activated by phosphoric acid figure 22. rate of adsorption of bismark brown on activated carbon prepared from date stone and activated by potassium hydroxide figure 23. rate of adsorption of bismark brown on activated carbon prepared from date stone and activated by zinc chloride figure 24. rate of adsorption of methyl orange on activated carbon prepared from date stone and activated by phosphoric acid figure 25. rate of adsorption of methyl orange on activated carbon prepared from date stone and activated by potassium hydroxide raw material activated agents adsorbate type bismark brown methyl orange r2 langmuir model r2 freundlich model r2 langmuir model r2 freundlich model date date date h3po4 koh zncl2 0.994 0.998 0.993 0.68 0.76 0.84 0.996 0.996 0.998 0.92 0.85 0.62 20 azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 figure 26. rate of adsorption of methyl orange on activated carbon prepared from date stone and activated by zinc chloride figure 27. first order kinetic model for the adsorption of bismark brown dye onto different types of prepared activated carbons at 30oc figure 28. first order kinetic model for the adsorption of methyl orange dye onto different types of prepared activated carbons at 30oc figure 29. second order kinetic model for the adsorption of bismark brown dye onto different types of prepared activated carbons at 30o c figure 30. second order kinetic model for the adsorption of methyl orange dye onto different types of prepared activated carbons at 30oc table 3. average value for freundlich isotherm parameters for bismark brown at different temperature (30,40,50,60) o c 1/n =slope kf =intercept activated agent raw material dye type 0.255 1.258 h3po4 date methyl orange 0.372 1.411 koh date 0.472 1.065 zncl2 date 0.306 1.466 h3po4 date bismark brown 0.363 1.593 koh date 0.427 1.525 zncl2 date table 4. the average value for langmuir isotherm parameters for methyl orange at different temperature (30,40,50,60) oc al ql activated agent raw material dye type 1.492 1.743 h3po4 date methyl orange 0.741 0.956 koh date 2.68 1.613 zncl2 date 0.912 0.901 h3po4 date bismark brown 0.562 0.546 koh date 0.385 0.503 zncl2 date azhaar radhi jabbar and abbas kalaf mohammad /al-qadisiyah journalfor engineering sciences 13 (2020) 013–021 21 5. conclusion the present study shows that the ac can be used as a potential adsorbent for the removal of both bismark brown and methyl orange from their aqueous solutions. the following conclusions can be drawn from the present work: 1. porous activated carbon could be prepared from date stone, the results showed that date stone activated with phosphoric acid, potassium hydroxide, or zinc chloride gives activated carbon with a good adsorption capacity highly porous structure and surface area with different shape and size. 2. the optimum condition to obtain high surface area and porosity depends on the agents used in the activation and the temperature hence, activation with high temperature resulted in lower surface area than lower temperature, therefore the suitable temperature for activation was 600oc in this work and potassium hydroxide gives activated carbon with good adsorption characteristic than that activated with phosphoric acid or zinc chloride. 3. the acidic dyes (methyl orange) show higher adsorption capacity than basic dye (bismark brown). 4. the adsorption isotherm data were fitted well by langmuir isotherm, for bismark brown and methyl orange, respectively, while the kinetics data were well represented by the pseudo-second-order kinetic model. 5. the results showed that the strength of adsorption for bismark brown is higher than methyl orange on most types of prepared activated carbons. hence, methyl orange was adsorbed with a higher amount than bismark brown, because methyl orange needs less energy for adsorption on activated carbon than bismark brown. references [1] o. gulnaz, a. kaya, f. matyar, b. arikan, sorption of basic dyes from aqueous solution by activated sludge, journal of hazardous materials, 108(3) (2004) 183-188. 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[7] k. jurewicz, r. pietrzak, p. nowicki, h. wachowska, capacitance behaviour of brown coal based active carbon modified through chemical reaction with urea, electrochimica acta, 53(16) (2008) 5469-5475. [8] a. ganesan, r. mukherjee, j. raj, m.m. shaijumon, nanoporous rice husk derived carbon for gas storage and high performance electrochemical energy storage, journal of porous materials, 21(5) (2014) 839-847. [9] b. royer, n.f. cardoso, e.c. lima, j.c. vaghetti, n.m. simon, t. calvete, r.c. veses, applications of brazilian pine-fruit shell in natural and carbonized forms as adsorbents to removal of methylene blue from aqueous solutions—kinetic and equilibrium study, journal of hazardous materials, 164(2-3) (2009) 1213-1222. 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[12] s. timur, i.c. kantarli, e. ikizoglu, j. yanik, preparation of activated carbons from oreganum stalks by chemical activation, energy & fuels, 20(6) (2006) 2636-2641. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٣ numerical analysis of steady free convection past over vertical plate abstract in this work a boundary layer analysis for free convection flow of viscous, incompressible fluid past over vertical plate is presented. a computer program is developed in quick basic language to obtain numerical solutions for the resulting governing equations (mass, energy, and momentum). a parametric study of all involved parameters is conducted and a representative set of numerical results for the velocity profile and temperature distribution are illustrated graphically and physical aspects of the problem are discussed. the validity of results is verified and shows that there is a good agreement between the results of the present numerical solution and the correlation related to it. ��د!�� �% �< �5� �2 ()� �'��� ا��%� ا�:1دي ��y'�ل ا�%�ارة ا� ا�<=>� ���دي p)� &'��اد 1 ���a'1 v. �8 هmا ا�s�g @? درا�� ا���* ا�� اري ا�� ��� (k�oج +f *1�l��ab�sط �� �@? إ )y,+1 (آ�����ت اcد����ا *��)�'�6�ا �$4،?�o�ا �? �8 هmا ا�g ��v4,�ب @�ز�) ا�, �� ودر!�ت ��). $4� ا�(��l و$4 � -^ ا���a+ ات�#�7l@?ا�� ارة و ���اول ���p+w ا2 ا�� � أ�( . ا�#��vk ا��8 @? ا���tل �'+s� ^�qل ا��#�#+�ت وا�lو �د -^ ا�94�g+^هm\ ا��را�� @��رب آg+ -��ر�ً��� �� t#�'+� وا���ا vk��#��1 . nomenclature symbol h heat transfer coefficient (w/m 2 k) gr grashoff number k thermal conductivity (w/mk) l characteristic length in the x direction n number of grid nodes in the vertical direction nu nusselt number nux local nusselt number pr prandtl number q heat transfer rate (w) mohamed fadhil thabit college of engineering al-qadisiya university ahmed ali shaker college of engineering al-qadisiya university _��s n�b 1�% آ� � ا���1�9 � :� ا�'�د��� أ2�1 ��* /�آ� آ� � ا���1�9 � :� ا�'�د��� al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٤ re reynolds number t temperature cp specific heat at constant pressure (j/kg.k) u velocity in axial direction (m/s) u dimensionless velocity in axial direction v velocity in vertical direction (m/s) v dimensionless velocity in vertical direction x dimensionless axial direction of the plate ∆x the distance between two nodal points in the axial direction (m) ∆x the dimensionless distance between two nodal points in the axial direction y vertical direction of the plate (m) y dimensionless vertical direction of the plate ∆y the distance between two nodal points in the vertical direction (m) ∆y the dimensionless distance between two nodal points in the vertical direction greek symbols symbol ν kinematic viscosity (m2/s) β thermal coefficient of volumetric expansion (k -1) µ dynamic viscosity (n.s/m2) ρ density of fluid (kg/m3) θ dimensionless temperature subscripts symbol i refers to iteration j,k the index increment along the axial and vertical direction w refers to wall ∞ fluid introduction free convection results when a fluid in the presence of gravity field undergoes density variations due to a uniform temperature distribution within the fluid. worster and alison leitch, 1985, investigated the development of density stratification in a confined fluid due to a buoyancy source which gives rise to a vertical convective boundary layer. they find that the stratification is significantly different when the boundary layer is laminar rather than turbulent. in particular, the magnitude of the density gradient in the fluid interior increases rather than decreases in the direction of flow of the boundary layer, and this density gradient varies smoothly so that there is no density front between the stratified fluid and the unmodified homogeneous fluid. laboratory experiments are described in which homogeneous fluid in a rectangular container was heated at a vertical sidewall. vertical temperature profiles and streak photographs were taken which show the dominant features of the stratification mechanism under laminar flow conditions. they review similarity theory for a vertical, laminar, free-convection boundary layer in a homogeneous environment, and develop new similarity solutions for convective boundary layers in stratified environments. we use these analytic results to interpret qualitative features of the experimentally observed flow fields and to develop an expression for the depth of the stratified layer as a function of time. amable y. kurdyumov, v., 1988 investigates the effect of the buoyancy-induced laminar flow and temperature fields associated with a line source of heat in an unbounded environment are described by numerically solving the non-dimensional bossiness equations with the appropriate boundary al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٥ conditions. the solution is given for values of the prandtl number, the single parameter, ranging from zero to infinity. the far-field form of the solution is well known, including a self-similar thermal plume above the source. the analytical description close to the source involves constants that must be evaluated with the numerical solution. these constants are used when calculating the free convection heat transfer from wires (or cylinders of non-circular shape) at small grashoff numbers. we find two regions in the flow field: an inner region, scaled with the radius of the wire, where the effects of convection can be neglected in first approximation, and an outer region where, also in first approximation, the flow and temperature fields are those due to a line source of heat. the cases of large and small prandtl numbers are considered separately. there is good agreement between the nusselt numbers given by the asymptotic analysis and by the numerical analysis, which we carry out for a wide range of grashoff numbers, extending to very small values the range of existing numerical results; there is also agreement with the existing correlations of the experimental results. a correlation expression is proposed for the relation between the nusselt and grashoff numbers, based on the asymptotic forms of the relation for small and large grashoff numbers. beithou, albayrak, abdulmajeed, 1998 present in their study, the variable porosity effects for a vertical plate in a variable porous medium. the governing partial nonlinear differential equations were transformed into a set of coupled ordinary differential equations, which was solved using the fourth-order runge-kutta method. the results obtained for the different power law index n, and variable porosity of the bed, were found to be in good agreement with previous studies. results show that when porosity increases temperature variation becomes steeper, and the nusselt number increases almost linearly with increasing porosity. singh and ajay, 2003, studied the two dimensional free convection and mass transfer flow of an incompressible, viscous and electrically conducting fluid past a continuously moving infinite vertical porous plate in the presence of heat source, thermal diffusion, large suction and under the influence of uniform magnetic field applied normal to the flow is studied. usual similarity transformations are introduced to solve the momentum, energy and concentration equations. to obtain local similarity solutions of the problem, the similarity equations are solved using perturbation technique. the expressions for velocity field, temperature distribution, concentration field, drag coefficient, rate of heat, and mass transfer have been obtained. the results are discussed in detailed with the help of graphs and tables to observe the effect of various parameters. ayo, 2006 studied the effects of aspect ratio on the transient free convection generated by a heated vertical plate in a rectangular cavity for the characteristics and rates of heat transfer from the plate into the surrounding fluid medium. the plate is assumed to be an isothermal plate at a high temperature, suddenly immersed in air at a lower temperature inside the cavity whose walls are also assumed to be adiabatic. the rate of heat transfer by convection is found to increase with aspect ratio. at large times the temperature field stratifies and the heat transfer to the medium approached zero, the velocity field decaying gradually and the flow approaches its eventual quiescence. chaudhary 2006 investigated an exact solution of the unsteady free convection boundary-layer flow of an incompressible fluid past an infinite vertical plate with the flow generated by newtonian heating and impulsive motion of the plate. the resulting governing equations are non-dimensional zed and their solutions were obtained in closed form with the help of laplace-transform technique. a parametric study of all involved parameters was conducted and a representative set of numerical results for the velocity, temperature and skinfriction is illustrated graphically and physical aspects of the problem were discussed. the effect of prandtl number on heat temperature may be analyzed he concluded that the thickness of thermal boundary layer is greater for air (pr = 0.71) and there is more uniform temperature distribution across the thermal boundary layer as compared to water (pr = 7.0) and electrolyte solution (pr = 1.0). he observed that the increase of prandtl number results in the decrease of temperature distribution. the reason is that smaller values of prandtl number are equivalent to increasing thermal conductivity and therefore heat is able to diffuse away from the heated surface more rapidly than for higher values of prandtl number. thus temperature falls more rapidly for water than air and electrolyte solution. the maximum of the temperature occur in the vicinity of the plate and asymptotically approaches to zero in the free stream region. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٦ ( ) ( ) ( ) ( ) ( ) ( ) ( ) ∞ ∞ = =∞ = = = =∞ = tyt txt txt xv yu xu xu w ,0 , 0, 00, 0,0 0, 00, mathematical model in this study the partial differential equations (pde's) which describe the natural convection past over vertical heated plate are explained. the problem configuration considered is shown in figure (1). the vertical plate is heated and the surrounding fluid is at rest. the vertical plate will be expressed in cartesian coordinates system with x direction taken parallel to plate and y direction normal to the plate. the following formulation is presented on the work of hornbeck, 1973 and incropera, 1996. continuity equation: 0 ).().( = ∂ ∂ + ∂ ∂ y v x u ρρ (1) for incompressible flow, ρ = constant and the continuity equation reduce to: 0= ∂ ∂ + ∂ ∂ y v x u (2) x-momentum equation: ( )∞−+      ∂ ∂ ∂ ∂ =      ∂ ∂ + ∂ ∂ ttg y u yy u v x u u x .... βρµρ (3) energy equation: 2 2 . y t k y t v x t uc p ∂ ∂ =      ∂ ∂ + ∂ ∂ ρ (٤) boundary conditions the boundary conditions specified for the classical free convection problem are: (5) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٧ the dimensionless quantities before undertaking a numerical solution, the equations (2) to (4) and boundary conditions (5) may now be put in dimensionless form by the proper choice of variables. the variables chosen are those used by hornbeck, 1973 (6) where ( ) 23 /... vglttbgr xw ∞−= is the grashoff number and gx is the x-component of the acceleration due to gravity dimensionless governing equations the dimensionless form is often more convenient to express the governing equations. it is developed to simplify the solution of many engineering problems and to avoid large quantities in calculation. when these variables are inserted into equations (2) to (4), the basic equations become in dimensionless form: continuity equation: 0= ∂ ∂ + ∂ ∂ y v x u (7) x-momentum equation: θ+ ∂ ∂ = ∂ ∂ + ∂ ∂ 2 2 y u y u v x u u (8) ( ) ( ) ( ) ( )                = = − = − − = = = ∞− = ∞ ∞ ∞ l y y grl x x lttg v x tt tt v vl v grv ul u ttgl v u wx w x . . . . . .. 4 2 2 β θ β al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٨ energy equation: 2 2 pr 1 yy v x u ∂ ∂ = ∂ ∂ + ∂ ∂ θθθ (9) dimensionless boundary conditions the boundary conditions in dimensionless form become: (10) numerical analysis the continuity, momentum, and energy equations which will be solved by using gauss elimination method. the resulting algebraic forms for all equations presented in this work are solved by using a computer program written in quickbasic language. the numerical formulation for continuity, momentum, and energy equations are shown below respectively hornbeck, 1973: ( ) ( ) ( ) 0 1 ,1 1 1,11, 1 1,1 = ∆ − + ∆ − ++ + +++ + ++ y vv x uu i kj i kjkj i kj (11) ( ) ( ) ( ) ( ) ( ) ( ) = ∆ − + ∆ − + −+ + ++ + + + + y uu v x uu u i kj i kji kj kj i kji kj 2 1 1,1 1 1,1 ,1 , 1 ,1 ,1 ( ) ( ) ( ) ( ) ( )i kj i kj i kj i kj y uuu .12 1 1,1 1 ,1 1 1,1 2 + + −+ + + + ++ + ∆ +− θ (12) ( ) ( ) ( ) ( ) ( ) ( )y v x u i kj i kji kj kj i kji kj ∆ − + ∆ − + −+ + +++ + + ++ + 2 1 1,1 1 1,11 ,1 , 1 ,11 ,1 θθθθ ( ) ( ) ( ) ( )2 1 1,1 1 ,1 1 1,1 2 pr 1 y i kj i kj i kj ∆ +− = + −+ + + + ++ θθθ (13) where the subscripts (i) & (i+1) indicate values obtained in the (i)th & (i+1)th respectively. equation (12) may be rewritten in a more useful form as: ( ) ( ) ( )            = =∞ = = = =∞ = 0,0 0, 10, 0)0,( 0),0( 0),( 0)0,( y x x xv yu xu xu θ θ θ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٥٩ ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )1 1,1 ,1 2 1 1,1 ,1 2 . 2 . 2 1 + ++ ++ ++ +         ∆ + ∆ +         ∆ − ∆ − i kj i kji kj i kj u x u y u y v y ( ) ( ) ( ) ( ) ( ) ( )i kj kj i kji kj i kj x uu u y v y ,1 ,,11 ,1 ,1 2 . . 2 1 + ++ + + + ∆ =         ∆ + ∆ − + θ (14) equation (14) written for k=1(1)n now constitutes n linear equations in the n unknowns ( )1 ,1 + + i kj u the set of linear equations may be written in matrix form for momentum equation as follows; ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )i n i n i i i i nj i nj i j i j i j i n i n i n i n i n iii iii ii u u u u u φ φ − − − φ φ φ = − − − × ω −−− −−− −−− ω ω ω − + + + −+ + + + + + + −−− 1 3 2 1 1 ,1 1 1,1 1 3,1 1 2,1 1 1,1 111 333 222 1 )( 1 βα βα βα βα β (15) where ( ) ( ) ( ) ( )y v y i kji k ∆ − ∆ −= + 2 1 ,1 2 α ( ) ( ) ( ) x u y i kji k ∆ + ∆ = + ,1 2 2 β ( ) ( ) ( )i kj kj i kji k x uu ,1 ,,1 . + + + ∆ =φ θ ( ) ( ) ( ) ( )y v y i kji k ∆ + ∆ −=ω + 2 1 ,1 2 equation (11) can be solved for ( )1 1,1 + ++ i kj v ( ) ( ) ( )( ) 1,1 1 1,1 1 ,1 1 1,1 ++ + ++ + + + ++ − ∆ ∆ −= kj i kj i kj i kj uu x y vv (16) equation (13) may be rewritten in a more useful form as: ( )( ) ( ) ( ) ( ) ( )( ) ( ) ( ) ( ) +         ∆ + ∆ +         ∆ − ∆ − + ++ + ++ ++ + + 1 1,1 1 ,1 2 1 1,1 1 ,1 2 . pr 2 . 2pr 1 i kj i kji kj i kj x u yy v y θθ ( )( ) ( ) ( ) ( ) ( ) kj i kji kj i kj x u y v y , 1 ,11 ,1 1 ,1 2 .. 2pr 1 θθ ∆ =         ∆ + ∆ − + ++ + + + (17) equation (17) written for k=1(1)n now constitutes n linear equations in the n unknowns ( )1 ,1 + + i kj θ the set of linear equations may be written in matrix form for energy equation as follows; al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٠ ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )i n i n i i ii i nj i nj i j i j i j i n i n i n i n i n iii iii ii / / 1 / 3 / 2 / 11 1 ,1 1 1,1 1 3,1 1 2,1 1 1,1 )/()/( / 1 )/( 1 )/( 1 / 3 )/( 3 )/( 3 / 2 )/( 2 )/( 2 / 1 )/( 1 φ φ − − − φ φ −φ = − − − × ω −−− −−− −−− ω ω ω − + + + −+ + + + + + + −−− α θ θ θ θ θ βα βα βα βα β (18) where ( ) ( )( ) ( ) ( )y v y i kji k ∆ − ∆ −= + + 2pr 1 1 ,1 2 /α ( ) ( )( ) ( ) x u y i kji k ∆ + ∆ = + + 1 ,1 2 / pr 2 β ( ) ( ) x u kj i kji k ∆ =φ + + , 1 ,1/ .θ ( ) ( )( ) ( ) ( )y v y i kji k ∆ + ∆ −=ω + + 2pr 1 1 ,1 2 / dimensionless local and average nusselt number the local nusselt number in dimensionless form is given by; ( )( )grx y nu y x 0=∂ ∂ = θ (19) in finite difference form this equation can be written as; ( )( )grxnu jjij x       +− = +++ 2,11,10, 43 θθθ (20) the average nusselt number is given by; ∫= x xm dxnu x nu 0 . 1 (21) results and discussion the layout of results include three values for grashoff number are selected (5,10, & 100) and two values for prandtl number are selected (0.71,7). the thermal boundary condition for this problem is constant wall temperature. these results includes the dimensionless velocity in x and y directions respectively (u,v) & dimensionless temperature distribution (θ ). figures (2 to 4) show the velocity profiles in the axial direction of the plate. it can be seen from these figures that initial velocity equal zero when x=0, then it increases gradually as x increases yielding to maximum values of u between surface and hydrodynamic boundary layer and theses maximum values are closer to wall than to surroundings. its observed that the increase in grashoff numbers yields to increase in axial velocity, positive values are selected since the temperature of the plate is less than surrounding temperature. the values of grashoff number are selected closed together in order to al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦١ make good comparison between the present work and the available models presented in the literature. figures (5 to 7) represent the effect of gr on the velocity profile in the horizontal direction. it’s observed that all values of v have negative values since positive values of gr means the plate is cooled from he surroundings (tplate< t ∞ ). figures (8 to 13) shows the temperature distribution along the plate. it’s noted that the increase in the pr valued result in decrease in the temperature distribution. the reason is that smaller values of prandtl number are equivalent to increasing thermal conductivity and therefore heat is able to diffuse away from the cooled surface more rapidly than for higher values of pr, spalding, 1980. increase in the gr number yields ton increase in velocity which in turn increases the temperature distribution. figures (14) shows the axial development of local nusselt number along the plate, nusselt number has the maximum value at the start of plate (first step) and then decreases gradually. the boundary layer thickness is zero at the start of plate , hence, there is no resistance against heat transfer which leads to raise the heat transfer coefficient value to maximum. conclusion the following conclusions are drawn from this study; the procedure adapted not need to assume any initial values that means the matrix is built, and then it solved using gausselimination method. all velocities in the horizontal direction of the plate have negative values indicates that the plate is cooled by the medium, so positive values for the grashoff number are selected. more heat is exchanged when prandtl number is increased. the thickness of the thermal boundary layer for air (pr=0.71) is greater than for water, (pr=7), and there is more uniform temperature distribution across the thermal boundary layer for air as compared for water. model verfication figures (15) & (16) show a comparison between present model and the models predicted by holman, 1999 and spalding, 1980 models respectively. it can be seen that the agreement between these results is fairly encouraging, and the trends of shape changes are also quite as anticipated. fig.(15),&(16) indicate that there are reasonable agreements between this work and these models and imply that present work is regarded as a potentially useful tool for predicting the velocity profile and temperature distribution. references amable y kurdyumov, v. "laminar free convection induced by a line heat source and heat transfer from wires at small grashof numbers." journal of fluid mechanics. vol. 362, pp. (199-227), 1998. anderson, d.a., tannehill, j.c., and pletcher, r.h., “computational fluid mechanics and heat transfer”, mcgraw-hill book company, new york, 1984. ayo s.a.,” transient free convection generated by a heated vertical plate in a rectangular cavity” au j.t. vol.10, no.1, pp (55-62), 2006. beithou n. al-bayrak k., abdul majeed a.,” effects of porosity on the free convection flow of non-newtonian fluids along a vertical plate embedded in a porous medium”, tr. j. of engineering and environmental science, 1998. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٢ chaudhary r.c., preeti jain, “unsteady free convection boundary-layer flow past an impulsively started vertical surface with newtonian heating”, rom. journ. phys., vol. 51, no. 9– 10, pp.(911–925), bucharest, 2006 grae worster and alison leitch,” laminar free convection in confined regions”, journal of fluid mechanics digital archive, 156 , pp (301-319), 1985. holman, j.p., “heat transfer”, mcgraw-hill book company, new york, 1999. hornbeck, r.w., “numerical marching techniques for fluid flows with heat transfer”, national aeronautics and space administration, washington, 1973. incropera, f.p. and dewitt, d.p., “fundamentals of heat and mass transfer”, john wiley & sons, new york, 1996. schlichting, h., “boundary-layer theory”, mcgraw-hill book company, new york, 1968. spalding, d.b. “natural convection heat and mass transfer”, volume 5, 1980. table (1): average nusselt number gr 5 10 100 0.71 1.386 1.52 2.173 pr 7 2.169 2.45 3.83 figure (1) physical model and its coordinates system y tw t∞ gx x fluid at rest al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٣ 0.00 0.04 0.08 0.12 0.16 u 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x 0.00 0.04 0.08 0.12 0.16 u 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x figure(2) velocity profile in the axial direction of the plate (gr=5) figure (3) velocity profile in the axial direction of the plate (gr=10) figure (4) velocity profile in the axial direction of the plate (gr=100) 0.00 0.04 0.08 0.12 0.16 0.20 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x u al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٤ -0.25 -0.20 -0.15 -0.10 -0.05 0.00 v 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x -0.25 -0.20 -0.15 -0.10 -0.05 0.00 v 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x figure (5) velocity profile in the vertical direction of the plate (gr=5) figure (6) velocity profile in the vertical direction of the plate (gr=10) -0.30 -0.25 -0.20 -0.15 -0.10 -0.05 0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 figure (7) velocity profile in the vertical direction of the plate (gr=100) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٥ x x θ 0.10 0.30 0.50 0.70 0.900.00 0.20 0.40 0.60 0.80 1.00 0.25 0.75 1.25 1.75 2.25 2.75 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x θ 0.10 0.30 0.50 0.70 0.900.00 0.20 0.40 0.60 0.80 1.00 0.25 0.75 1.25 1.75 2.25 2.75 0.00 0.50 1.00 1.50 2.00 2.50 3.00 figure(8) temperature distribution in the axial direction of the plate (pr=0.71, gr=5) figure (9) temperature distribution in the axial direction of the plate (pr=0.71, gr=10) figure (10) temperature distribution in the axial direction of the plate (pr=7, gr=5) figure (11) temperature distribution in the axial direction of the plate (pr=7, gr=10) 0.10 0.30 0.50 0.70 0.900.00 0.20 0.40 0.60 0.80 1.00 0.25 0.75 1.25 1.75 2.25 2.75 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x θ 0.10 0.30 0.50 0.70 0.900.00 0.20 0.40 0.60 0.80 1.00 0.25 0.75 1.25 1.75 2.25 2.75 0.00 0.50 1.00 1.50 2.00 2.50 3.00 x θ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٦ x θ x θ 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 0.10 0.30 0.50 0.70 0.900.00 0.20 0.40 0.60 0.80 1.00 0.25 0.75 1.25 1.75 2.25 2.75 0.00 0.50 1.00 1.50 2.00 2.50 3.00 0.10 0.30 0.50 0.70 0.900.00 0.20 0.40 0.60 0.80 1.00 0.25 0.75 1.25 1.75 2.25 2.75 0.00 0.50 1.00 1.50 2.00 2.50 3.00 figure (12) temperature distribution in the axial direction of the plate (pr=0.71, gr=100) figure (13) temperature distribution in the axial direction of the plate (pr=7, gr=100) figure (14) local nusselt number in the axial direction of the plate (pr=7, gr=100) x nux al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٧ ( )ηf ′ ( )ηθ 4 1 4       = x gr x y η 4 1 4       = x gr x y η ( ) x x grv xv f 2 =′ η ( ) ∞ ∞ − − = tt tt w ηθ 1.00 3.00 5.000.00 2.00 4.00 6.00 0.05 0.15 0.25 0.00 0.10 0.20 0.30 saplding model present model 1.00 3.00 5.000.00 2.00 4.00 6.00 0.20 0.60 1.00 0.00 0.40 0.80 1.20 present model spalding model figure (15) velocity variation across boundary layer, a comparison between present model and spalding model figure (16) temperature variation across boundary layer, a comparison between present model and spalding model al-qadisiyah journal for engineering sciences 15 (2022) 067–072 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: pme.19.38@grad.uotechnology.edu.iq (zainab ali) https://doi.org/10.30772/qjes.v15i1.815 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. studying the effect of multicomponent nano-coating alloy on hydrogen embrittlement of aisi 1018 steel by gas-phase process zainab z. ali*, baha s. mahdi and ameen d. althamer production and metallurgy department, university of technology, baghdad, iraq. a r t i c l e i n f o article history: received 26 march 2022 received in revised form 25 may 2022 accepted 18 june 2022 keywords: hydrogen embrittlement tensile test dc sputtering bni-2 sem. a b s t r a c t the present study is attempted to investigate the influence of multicomponent ni-alloy (bni-2) on the hydrogen embrittlement (he) behaviour of aisi 1018 steel by using cathodic protection and tensile test. the results show that the he indexes (hei) decrease notably when aisi 1018 steel is coated with bni-2 alloy by dc sputtering process. this coating processes leads to decrease in he susceptibility of the aisi 1018 steel, which can be rationalized to the enhancement in corrosion resistance and the decrease in hydrogen absorption of the aisi 1018 steel after coating. the tensile strengths of bared samples were decreased with increasing charging time until 24 hours when stable at values 350 mpa. while the coated samples showed an increasement in the tensile strength from 570 mpa to 750 mpa. stabilization in strength at value of 600 mpa was observed after exceeding 48 hours. also, the tensile test for uncoated specimens indicated a clear reduction on the modulus of elasticity compared with other coated ones. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the deterioration effect of hydrogen penetration on steel properties have been observed since 1870s, johnson noted the changes in the toughness and breaking strain of iron, when it was temporarily immersed in acid for just a few minutes. the acids which produce the hydrogen during the reaction with iron lead to a serious deterioration in properties. [1]. rates of hydrogen diffusion in metals depend on the hydrogen concentration gradient, temperature, stress, susceptible materials, hydrogen-diffusion coefficients (d) and the crystal structure [2]. for example, high-strength martensitic steels are so susceptible to hydrogen penetration, since cracks are observed at solute hydrogen concentrations less than 1 ppm (wt.). for ferritic steels with strengths less than 750 mpa, relatively high hydrogen concentrations (~10 ppm) are often necessary for the hydrogen penetration to be significant. nickel alloys, alumina, stainless steels, and copper alloys show little susceptibility to hydrogen penetration; fig. 1, [2-3]. the main sources of hydrogen can be summarized as cathodic protection, pickling, electroplating, special case of arc welding, galvanic corrosion, and acid or gasses chemical reactions [4]. hydrogen penetration weakens the interatomic bonds between the grains of steel casing and causes premature failures. this phenomenon could pose a risk to the sustainability of the oil and gas projects. therefore, nano-coatings were used to treat this problem. nanocoating term is used if the coating thickness is referred to as thin films or the structures are in nanostructure scales. there are various methods of producing nano-coatings, thin films, and nanostructure [5], which are chemical vapor deposition (cvd) and physical vapor deposition (pvd). the phase structure, morphology, and mechanical properties of coatings deposited using dc. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i1.815 http://creativecommons.org/licenses/by/4.0/ 68 zainab z. ali et al. /al-qadisiyah journal for engineering sciences 15 (2022) 067–072 figure 1. hydrogen diffusion coefficients for fe and nb (bcc), ni (fcc) and ti (hcp) as a function of temperature [2] [3] such as type of inert gas, working pressure, voltage, deposition time, substrate temperature, the distance between target and substrate, the surface finish of substrate, ion current, etc. [6] [7] [8]. they are directly affecting phase structure, preferred orientation, chemical composition, and deposition rate of the coatings [9] [10] several researchers revealed the effect of nanocoating on hydrogen penetration and corrosion resistance for steel. s. marikkannu and others reported that indium oxide in 2o3 nano coating deposited films are successfully deposited on different substrates by using the gas phase process, the results are encouraging for the use of thin films in low-cost industry applications [11]. bni-2 alloy has been used in applications in environments withstanding temperatures up to 1,000 °c, with properties that include abrasion resistance to guard against erosion, kinetics that makes it impervious to atomic hydrogen penetration and ingress can cause steel to become brittle and crack. this work focuses on reducing the hydrogen embrittlement in aisi 1018 steel by coating processes. multicomponent nano-coating alloy bni-2 as protective films will be deposited by using dc sputtering technique. 2. material and experimental setup 2.1. materials used steel (aisi 1018), which is used in oil industry storage tanks, is used as a substrate material exposed to hydrogen charging with and without coating. the chemical composition analysis of this workpiece was done by using spectrometer analysis instrument available in baghdad in the general company for examination and rehabilitation engineering, as shown in table 1. table 1. chemical composition of test specimen (in %). c si mn cr mo ni co cu nb fe thin film deposition has been obtained via dc or direct current sputtering. the target material used was the foil of nickel alloy called bni-2 or (en iso 17642). the thickness of this foil was 35 mm and its chemical composition are explained in table (2) [12]. table 2. chemical composition of target foil (bni-2). cr b p si fe c ni 14 3 0.02 4.2 3 0.04 2.2. specimen preparation surface preparation of substrate samples was carried out by emery papers of silicon carbides with different grit sizes from 220, 400, 800, and 1000. the samples also were ultrasonically cleaned in ethanol for 15 min prior to the deposition process. 2.3 coating process coating process was performed by dc sputtering, where the nickel alloy foil was prepared as a circular target with a diameter of 50 mm and fixed 2.5 centimeters above the substrate of specimens. the chamber was evacuated partially to a pressure of 10-1 mbar of pure argon gas. the target was bombarded with ionized argon gas molecules causing atoms to be “sputtered” off into the plasma. these took off atoms then deposited when they condensed as a thin film on the substrate to be coated. adjusted dc sputtering for coating thin-film current was 16 ma and the sputtering time was fixed for all specimens to 50 minutes. 2.4 effect of hydrogen embrittlement (he): firstly, the dog bone-shaped (tensile) specimens of mild steel were welded to one end of a copper wire by discharge welding, and then the other end of the wire was connected to the cathode wire of the power supply. the tensile specimens were covered with an acid-resistant insulating material (epoxy) except the gauge length remained uncoated, and the uncoated area calculated for specimens was about 250 mm2, as shown in figure -3-. the anode was a stainless-steel bar. figure 2. coated and uncoated work substrate before covering zainab z. ali et al. /al-qadisiyah journal for engineering sciences 15(2022) 067–072 69 sulfuric acid (h2so4) dissolved in distilled water with a concentration of 0.5 m was used to create hydrogen-releasing environments. the test specimens were immersed in h2so4 solutions in a beaker. for better understanding and statistical analysis of hydrogen damage, ten specimens were immersed in each of h2so4 solutions, a half of them were coated and the other not; they were immersed for different intervals of time (2, 4, 6, 24, and 48 hours). the power supply was adjusted with 0.3 v and the average current was 0.4 a with a current density of 120 ma/cm2. figure 3. partially covered tensile test specimens by epoxy resin figure 4. specimen failed after tensile test. 2.5. machining testing tensile test specimens were prepared according to astm e8 with a gage length of 25 mm, and the total length for each specimen was 100 mm. the machining process for all specimens was done using a cnc machine, as shown in fig. 2. 2.6. morphology analysis coated and charged samples with dimension (10×10) mm were prepared to test using sem. figure 5 shows the coated aisi 1018 steel with bni-2 alloy, where the scratched surface belongs to the prior grinding process. from the image, the coating layer completely covers the steel surface. 3. results and discussions 3.1 hydrogen penetration: standard tensile specimens of aisi 1018 steel were charged with hydrogen, the specimens were tested by a tensile test at the room temperature, and the results are shown in fig. 5. figure 5. a graph illustrating the results of all tensile tested specimens the first impression of the tested specimens is that the uncharged sample will give the maximum tensile strength as it is known, in this experiment it reached to 490 mpa, where the uncharged specimen is free of side effects of hydrogen penetration defects. also, all the charged specimens will suffer from defects according to charging time and this is also applied to the coated specimens, where the coat has not blocked all the hydrogen atoms but it can reduce the penetration. in fig. 5, the result is different from what was expected. charging the uncoated specimens give the expected results as mentioned above by decreasing the tensile strength for all the uncoated specimens but at different values when compared to the charging time. fitting curve for uncoated specimens as depicted in fig. 6 has been done to understand the relation between tensile strength as mechanical properties and hydrogen charging. as it is expected, the uncoated specimens evince a decrease in tensile strength with longer charging time until reaching a steady state value about 30% of the original uncharged metal after 24 hours of immersion in dilute sulfuric acid. in the actual embedded pipelines in sites, the same happened but for a longer time depending on the cathodic current density, soil type, and humidity. nearest curve fitting is the second order polynomial formula as stated in eq. 1, where σ u is the tensile strength in mpa, and t is the charging time in hours. note that this equation is applied for a specific environment involved in this work. by curve fitting, the sputtered tensile charged specimens illustrated fig. 7 showed the unexpected behavior, where the tensile strength increased above the uncharged steel for just nano coating thickness. and, eq. 2 represents the second-order polynomial curve fitting, the increasing percentage value can be 24% which is very high, and it is noted that this happened without heat treatment. 𝜎𝑢 = 503 − 9.299𝑇 − 0.124𝑇 2 (1) 𝜎𝑢 = 405 − 29.3𝑇 − 0.556𝑇 2 (2) 70 zainab z. ali et al. /al-qadisiyah journal for engineering sciences 15 (2022) 067–072 figure 6. tensile strength for uncoated specimens with different charging times. figure 7. tensile strength for coated specimens with different charging times. by curve fitting, the sputtered tensile charged specimens illustrated in fiq. 7 showed the unexpected behavior, where the tensile strength increased above the uncharged steel for just nano-coating thickness. eq. 2 denotes the fitting of a second-order polynomial curve. the increasing percentage value can be 24% which is very high, and it is noted that this happened without heat treatment. increasing tensile strength in coated and charged hydrogen specimens necessitates additional tests such as tem, which are not included in this study. however, there are several explanations for this phenomenon, the first of which is the entrance of the coating elements into the base metal via a diffusion process aided by the high energy of hydrogen. these elements react with iron and form strain hardening inside metal, finally the occurrence of phase transformations. but this explanation is weak because the coating elements as nickel, chromium and others are hard to diffuse substitutionally at room temperature. the second explanation is that the bni-2 nano-coating layer on steel could heal most nano and micro cracks in the substrate surface and reduce the stress concentrations, causing improved mechanical properties [13]. the third explanation which needs good attention and is the nearest to be approved is that the nano coating layer acts as a sieve for the hydrogen atoms, which means the coating allows the hydrogen atoms to pass into the structure in a small amount. therefore, they are distributed within the crystal lattice in a uniform and homogeneous manner. hydrogen atoms occupy interstitial sites within the crystal lattice, leading to a distortion in it (because the space inside the lattice is not enough to accommodate a solute atom without the displacement of neighboring atoms). this distortion is the tension and compression energy between the iron and hydrogen atoms inside the metal, where the crystal structure is stable and the distance between the iron atoms are fixed. so, when the hydrogen atoms enter, the iron atoms move away from each other; thus, the tensile and compressive forces are generated, and it looks like cold work inside the metal [14]. 3.2 sem analysis and finding the thickness: figure 8 seems that it is not completely uniform as there are some scratches like a terrace, this is due to surface finish, and this is because of the nature of the sputtering process which requires some roughness to increase the surface area and mechanical interlocking between the coating atoms and substrate. it is clear that these terraces are formed by the stacking of layered crystals. on the other hand, roughness is required to reduce the hydrogen blistering as concluded by several researchers. the grinded surface presents a lower sensitivity to the hydrogen-induced blisters in comparison with the polished surface, which is attributed to the suppression of hydrogen invasion caused by higher residual compressive stress and higher dislocation density in the grinded surface [15]. figure 8. sem image for coated surface with low magnification to identify the thickness of the nanolayer, the best method is by scratching the coated surface using a sharp razer smoothly. by increasing the magnification, the scratch becomes clearer, and the white marked region represents the accumulated coating layer of bni-2, as shown in fig. 9. to recognize the layer thickness, the magnification must be higher. with higher magnification and lower beam intensity (4 ma) for the electron beam, the segmented separated coating layers from the surface can be seen, as portrayed in fig. 10. thin fragmented layer parts are shown in fig. 10 as zainab z. ali et al. /al-qadisiyah journal for engineering sciences 15(2022) 067–072 71 semi-transparent to electron beam as marked some of them by dotted yellow lines to make better vision. figure 9. sem image for scratched surface using sharp razer figure 10. sem image for the scratched surface in figure (10) with higher magnification. to confirm the thickness result, another image with a higher magnification was taken as shown in fig. 11, where the measured thickness was 114.56 nm. according to the above, one can say that the coat layer thickness lies between (90 to 110) nm, and it can be classified as nano or thin layer. fig. 12 displays the sem image with low magnification for coated charged samples, and it is observed that there are different areas of the inhomogeneous samples. in this figure, the microcracks, and ripping of coating from small areas, as well as some spots, can be seen; this means that the hydrogen atoms began to slightly and regularly penetrate the coating layer. coating microstructure plays an important role in affecting mechanical and tribological properties as well as hydrogen permeation, since the nickel structure (fcc), is a better metallic coating type for resisting the hydrogen penetration than (bcc) elements because the packing factor of (fcc) is more than the (bcc) structure related to fewer voids between atoms in (fcc) compared to the (bcc) crystal lattice. therefore, the hydrogen atoms cannot easily penetrate throughout the structure, and that is happened in this sample. the surface roughness values for coated, uncoated, and charged specimens are measured by using a roughness device, and the results were as follows. the substrate roughness before coating and before the charging process was found to be equal to 0.1466 µm, coated uncharged steel equal to 0.093 µm, and coated glass was 0.04 µm. the roughness that appeared in the steel-coated layer is related to the steel surface itself and is not due to the sputtering process as in fig. 13 showing the glass coated with the same amount (time and other parameters) for steel. the smoothness of the coated glass is higher in orders compared to the coated steel surface. when comparing figs. 8-13, one can notice clearly the homogeneity of lass rather than metal substrate, because the tops and valleys in metal substrate act as nuclei which collect the sputtered atoms, but that does not exist in a glass. this is the reason for different images in metal and glass substrates. figure 11. high magnification sem images show measurement of nano sputtering layer. figure 12. sem images of bni-2 deposited on metal with he. 72 zainab z. ali et al. /al-qadisiyah journal for engineering sciences 15 (2022) 067–072 figure 13. sem image of the bni-2 deposited on glass. 4. conclusions 1) uncoated aisi 1018 steel and charged by hydrogen manifested a decrease in tensile strength until a steady state about 30% of its original tensile strength after a charging time of 24 hours with a current the density of 120 ma/cm2. 2) increasing the tensile strength by 24% to the original metal by hydrogen charging for bni-2 nanolayer on the aisi 1018 steel. 3) most suggested cause of increasing the tensile strength by hydrogen charging for the coated metal is the action of the nanocoating layer as a sieve for the diffused hydrogen atoms distributed interstitially between the iron atoms, leading to stress in the lattice as occurring in the cold work strengthening. 4) average coat thickness of bni-2 on aisi 1018 steel was 90 to 100 nm and the maximum coat layer was 114.5 nm. references [1] w. h. johnson, proceedings of the royal society of london, p. 168–179., 23 (1875). [2] j völkl and g. alefeld, "hydrogen diffusion in metals," in diffusion in solids, p. 231–302, 1975. [3] m. d. a. s. z. h.-j. christ, "hydrogen diffusion coefficients in the titanium alloys imi 834, ti 10–2–3, ti 21 s, and alloy c, metal," pp. 1507–1517, 2000. [4] s. lynch, "hydrogen embrittlement (he) phenomena and mechanisms," in stress corrosion cracking, australia, 2011, pp. 90-130. [5] a. l. b. injeti g., "“electrodeposition of nanostructured coatings and their characterization”," j. of science and technology of advanced materials, pp. 12 1129, 2008. [6] b. warcholinski and a. gilewicz, " effect of substrate bias voltage on the properties of crcn and crn coatings deposited by cathodic arc evaporation.," vols. 90, p. 145–150., 2013. [7] a. obrosov, m. naveed, a. volinsky and s. weiß, " substrate frequency effects on crxn coatings deposited by dc magnetron sputtering.," vols. 26, p. 366 –373., 2017. [8] a. krella and a. czyzniewski, "cavitation resistance of cr-n coatings deposited on austenitic stainless steel at various temperatures.," vols. 266, p. 800–809, 2009. [9] x. wan, s. zhao, y. yang, j. gong and c. sun, " effects of nitrogen pressure and pulse bias voltage on the properties of cr-n coatings deposited by arc ion plating.," surf. coat. technol., vols. 204, p. 1800–1810, 2010. [10] h. shah, r. jayaganthan and d. kaur, " effect of sputtering pressure and temperature on dc magnetron sputtered crn films," vols. 26, p. 629–637, 2010. [11] m. k. a. a. s. marikkannu, "studies on jet nebuliser pyrolysed indium oxide thin films," journal of ovonic research, vol. 10, pp. pp. 115 125, august 2014. [12] metals handbook, " properties and selection nonferrous," in asm, 2015, pp. p1832. [13] k. n., j.-m. y., j. k. tamaki naganuma, "the effect of a compliant polyimide nanocoating on the tensile properties of a high strength pan-based carbon fiber," composites science and technology, 2009. [14] underneath the bragg peaks – structural analysis of complex materials, vol. 16, pp.2 – 481. 2012. [15] y. w. 1. w. h. 1. j. z. 2. a. x. w. 1. xinfeng li 1, "effect of surface roughness on hydrogen-induced blister behavior in pure iron," metals, vol. 10, no. 745, 2020. zainab z. ali et al. /al-qadisiyah journal for engineering sciences 15(2022) 067–072 73 article al-qadisiyah journal for engineering sciences 12 (2019) 246–253 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7832685960. *corresponding author email: haitham.althairy@qu.edu.iq (haitham al-thairy) https://doi.org/10.30772/qjes.v12i4.641 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. numerical study on the structural behavior of rc beams after exposure to elevated temperature sajida kadhem al-jasmi a, haitham al-thairy a * a civil engineering department, college of engineering, university of al-qadisiyah, iraq. a r t i c l e i n f o article history: received 11 november 2019 received in revised form 20 october 2019 accepted 30 october 2019 keywords: numerical model rc beams elevated temperature abaqus heating rate a b s t r a c t this paper presents a numerical simulation of the structural response of reinforced concrete (rc) beams under elevated temperature using the commercial finite element package abaqus. a numerical model is firstly suggested by selecting the appropriate geometrical and material properties of the rc beam model at elevated temperature. thereafter, the suggested numerical model was validated against the experimental tests conducted in this study. the validation results in terms of temperaturestime histories; load-mid span deflection of the rc beams have confirmed the accuracy of the suggested numerical model. the validated numerical model was implemented in conducting a parametric study to investigate the effects of two important parameters on the behavior and failure of rc beams under elevated temperature. these parameters are the effect of the high ranges of elevated temperatures; and the effect of heating rate. the parametric study results have revealed that the failure load and the ductility of rc beams under elevated temperature are not considerably influenced by changing the heating rate. it has also been concluded that the ultimate load capacities of rc beams have considerably decreased by 55.49%, 74.72%, and 81.31% comparing with the control rc beam when they exposed to temperature values of 600 ºc, 700 ºc, and 800ºc respectively. these conclusions may be used in the design of rc beams subjected to fire induced temperature. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction fire induced temperature is one of the most extreme loading conditions that any concrete building may be prone to during its service life. the elevated temperature may cause significant degradation of the mechanical properties of the concrete leading to progressive collapse and failure of the entire structures. one of the examples is the collapse of the world trade centre (wtc) in 2002 which was mainly caused by the elevated temperature induced from the fire following the explosions. ever since, the awareness of the engineering community has been raised to the importance of incorporating the effect of elevated temperature in the design procedures of structural members. therefore, a considerable amount of experimental research studies have been conducted during the past two decades on the effect of elevated temperature on the behaviour of concrete members. however, few numerical studies were published on the rc beams members at fire due to the complexity of the problem which involves highly geometrical and material nonlinearities. for example yue et al. [1] has carried out numerical simulations to study the fireproof behavior of simply supported rc beams strengthened by stranded mesh and polymer mortar (smpm) by using the finite element software abaqus. the coupled http://qu.edu.iq/ mailto:haitham.althairy@qu.edu.iq https://doi.org/10.30772/qjes.v13i sajida kadhem al-jasmi and, haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 247 ` temperature and displacement analysis is fully considered with thermal and mechanical properties of concrete being adopted according to ec4 [2] and others taken from previous researcher studies. the numerical results have revealed that the coupling of displacement and temperature fields can be reasonably modelled by abaqus. in addition, gao et al [3] presented a three dimensional fe model to predict the thermal and the mechanical behaviour of rc beams at high temperature. a concrete damage plasticity constitutive model in abaqus [4] was used to model the mechanical behaviour of concrete. the stress-strain relationship and the thermal properties of steel and concrete at elevated temperature were adopted according to ec2[5] and ec3 [6]. in addition, the concrete reduction factors under elevated temperature were taken according to the experimental tests from previous researcher studies and the reduction factors of steel were taken according to ec3 [6]. the results have shown that the inclusion of steel to concrete interfacial behaviour leads to more accurate predictions of the deflection of rc beams exposed to fire. also, the numerical study conducted by ozˇbolt et al [7] has developed a three dimensional finite element model to study the response of simply supported rc beams made from crushed stone aggregate. iso 834 [8] standard fire curve was used under elevated temperatures up to 300ºc followed by mechanical loading. the thermal and mechanical procedure available in abaqus was utilized to perform the analysis. the thermal properties of steel and concrete used are taken from ec2 [5] and ec3 [6]. the results indicated that the employed numerical modeling technique can successfully predict the behaviour of the rc beam under fire and followed by mechanical load. further the used 3d thermo-mechanical model is useful numerical tool for the realistic prediction of the behaviour of rc structures exposed to high temperature. in the same contexts, el-tayeb et al [9] have carried out a numerical investigation on the response of rc beams and frames under the effect of thermal loads using the fe software abaqus. the beams and frames were modelled by accounting the material nonlinearity including cracking behaviour and the gradients of temperature are assumed linear, nonlinear and uniform. the results have indicated that the behaviour of beams and frames is largely deviated depend on the trend of the temperature gradient (i.e. linear or nonlinear). therefore, the nonlinear gradient of temperature was suggested to be implemented in the analysis. the above-mentioned research studies have shown that the finite element package abaqus has widely been utilized in simulating the behaviour and failure of rc beams at elevated temperature with a very reasonable accuracy. the stress-strain model of concrete under elevated temperature proposed by ec2[5], ec3[6] and ec 4 [2] was successfully used to predict the degradation of the concrete strength under high temperature. however, the previous numerical models have not been validated against experimental tests results with different ranges of elevated temperatures and have not been used to conduct comprehensive parametric study. therefore, the main object of the current study is to develop a more accurate numerical model to simulate the behaviour of rc beams under elevated temperature using the fe software abaqus/standard. in addition, the validated numerical model will be used to conduct a parametric study to investigate the effects of two important parameters on the behaviour and failure of rc beams at elevated temperature. these two parameter have not been be investigated by the previous numerical research studies. 2. the fe model of the rc beams 2.1. material modeling the concrete damaged plasticity model (cdpm) available in abaqus/standard was used in this study to simulate the behavior of the concrete material under ambient and elevated temperature up to failure. the cdpm uses several parameters to simulate the plastic behavior of concrete. in the present model, some of the required plasticity parameters for rc beams were taken as the default values in abaqus. one the other hand, the mathematic constitutive model for the compressive stress-strain relationship of concrete by ec4 [2] was adopted at ambient and elevated temperatures. the values of yielding and crushing strains of concrete at different temperatures were taken according to ec4 [2]. to account for the degradation of the mechanical properties of concrete at elevated temperature, reduction factors of compressive strength were obtained from the experimental tests conducted in this study (see fig. 1). figure 1. stress strain relationships of rc beams at various temperatures the tension stiffening of concrete at ambient and elevated temperature was defined in terms of the fracture energy (gf) available in abaqus [10, 11] as show in fig. 2. according to ceb-fip model [12], the value of gf can be obtained as a function of the maximum aggregate size (dmax) and the required concrete strength as presented in table 1. on the other hand the reduction factors of tensile strengths of concrete at elevated temperature suggested by ec2 [5] was used in the tension stiffening model to account for the effect of the elevated temperature. figure 2: bilinear softening tension used for nwc [10, 11]. 0 5 10 15 20 25 30 35 0 0.02 0.04 0.06 n 20 n 390 n 570 n 600 n 700 n 800 248 sajida kadhem al-jasmi and haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 table 1: values of gf for different aggregate sizes and concrete strengths according to [10] one the other hand, the tension damage parameters was used in this study to detect the crack initiation of rc beams at ambient and elevated temperature. the tension damage parameter is calculated from the equation suggested by abaqus [5] as follows: dt=1 𝜎𝑡 𝑓𝑐𝑡𝑚 (1) where σt is the tension stress of concrete at the stage of analysis where the damage parameter is to be calculated and fctm is the ultimate tension stress of concrete. for the reinforcement bars, the mathematic constitutive model of the stress-strain relationship of steel at tension proposed by ec4 [2] for ambient and elevated temperature was used. the yielding stress, modules of elasticity and poisson’s ratio of the steel material at ambient temperature were taken as 414 mpa, 2×105mpa, and 0.2 respectively. 2.2. geometrical modeling the three dimensional eight nodes solid element with reduced integration and hourglass control (c3d8r) in abaqus/standard shown in fig. 3-a was used in this study to model the rc beams, bearing steel plate and supporting steel plates during the structural analysis. while, in the heat transfer analysis, the three dimensional eightnode solid liner heat transfer element (dc3d8) with a temperature degree of freedom was used (see fig. 3-a). one the other hand, the reinforcing steel bars was modeled by using a three-dimensional two-node linear displacement truss element (t3d2) during the structural analysis while a two-node heat transfer link element (dc1d2) with a temperature degree of freedom was utilized during the heat transfer analysis as shown in fig. 3-b. table 2 summary all types of element used in the numerical model of this study. a :c3d8r and dc3d8 elements b: t3d2 and dc1d2 elements figure 3. types of elements used in the numerical model table 2: types of elements used in the numerical mode 2.3. assembly of the numerical model fig. 4 shows the assembly of all parts used in the numerical model of this study including the details of the reinforcement bars. bearing and supporting steel plates with dimensions of (150×100×10) mm and (150 ×80 ×10) mm (length ×width ×depth) respectively were used to eliminate localizing of stresses at supporting and loading areas. the tie type of the constrain option in abaqus was used to tie up theses plates to the rc beams. the boundary conditions of the beams were modeled to simulate the simply supporting boundary conditions as used in the experimental tests. in addition, the embedded reign type of the constrain option in abaqus was utilized to set the interaction between the reinforcement steel bars and the concrete beams. a: rc model in abaqus b : rc reinforced figure 4: assemblage of the numerical models 2.4. analysis procedure the partially coupled thermal and mechanical analysis in abaqus/standards was used in the present study to analyze the rc beams under elevated temperature followed by static point load. in this analysis procedure, the heat transfer analysis is carried out to predict the temperature distribution over the rc beams while mechanical analysis was carried out to determine the stress, strain and displacement distributions at the beam up to failure. the main features of each phase of analysis are described as follows: 2.5. heat transfer analysis in this analysis, the rc beams were heated up to the intended degree of temperature which is applied over the whole beam as a boundary condition following the temperaturetime histories obtained from the corresponding experimental tests conducted in this study as shown in fig. 5. the thermal expansion, specific heat and thermal conductivity of concrete and the steel were all defined as a function of temperature in the material properties of the numerical model using values supposed by the ec4[3]. dmax(mm) gƒ(n/m) c12 c20 c30 c40 c50 c60 c70 c80 8 40 50 65 70 85 95 105 115 16 50 60 75 90 105 115 125 135 32 60 80 95 115 130 145 160 175 material type structural analysis heat transfer analysis rc beams c3d8r dc3d8 bearing and supporting steel pates c3d8r dc3d8 reinforcing steel t3d2 dc1d2 sajida kadhem al-jasmi and, haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 249 ` a :n250ºc b :n390ºc c :n460ºc d :n570ºc figure 5: temperature–time histories at furnace, rc beam pecimens and the steel bars used in the present study 2.6. structural analysis the structural analysis was carried out after heat transfer analysis to predict the structural behavior of rc beams after temperature exposure. the distribution of temperature over the rc beams was restored from the heat transfer analysis as an initial step of the rc beams using the predefined fields option in abaqus. a displacement controlled structural analysis was carried out by applying a lateral displacement as a boundary condition at the center of rc beams. 3. validation of the numerical model. to ensure the reliability of the developed numerical model, experimental tests were carried out in this study on rc beams subjected to elevated temperature followed by concentrated static load at the beam’s mid-span .the numerical simulation results obtained from the suggested model will be compared with the experimental tests results. the section below describes the experimental tests used in the validation exercises. 3.1. experimental tests five rc beams with cross sectional dimensions of 150mm× 240mm (width × height) and total length of 1250 mm were cast, cured, heated and tested in the present study. the average values of compressive and tensile strengths of the concrete used in all rc beams specimens are 31.45 mpa and 2.875 mpa respectively. the geometrical and reinforcing details of rc concrete beams are shown in fig. 6. the rc beams were designed to resist lateral concentrated load at beams mid-span of 150kn according to aci 318-2014 13. four rc beams were tested after exposing to four different elevated temperatures which are 250 ºc, 390ºc, 460ºc, and 570ºc while one beam was tested under ambient temperature ( i.e. 20 ºc) and it was considered as the control beam. for each of the four heated rc beams, the temperature was maintained constant for about half an hour when it reaches the target value. an electric furnace with dimensions of 1300mm (length) × 330mm (depth) and 290mm (height) and maximum temperature of 900ºc was designed, manufactured and calibrated in this study and used to heat up the rc beam specimens as shown in fig. 7. the average heating rate of the furnace was controlled to be 10ºc/min and remained in furnace for about half hour, then, the rc beams were naturally cooled down to ambient temperature . figure 6: dimensions and reinforcement details of rc beams 20 120 220 320 0 20 40 60 80 concrete steel furnace 20 120 220 320 420 520 0 50 100 150 200 concrete steel 20 120 220 320 420 520 620 0 50 100 150 200 250 300 350 concrete steel furance 20 140 260 380 500 620 740 0 100 200 300 400 500 600 concrete steel furance 250 sajida kadhem al-jasmi and haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 figure 7: the electric furnace setup all rc beams were subjected to a monotonically increased concentrated static load at the beams mid span up to failure using the universal testing machine available at the college engineering/university of al-qadisiyah/. load cell and linear variable displacement transformer (lvdt) were used to measure and capture loadlateral displacement relationships of the rc beam under different elevated temperatures. the ends support conditions of the rc beam specimens were arranged in the tests to simulate the simply supported condition by allowing the ends to move in axial directions and to rotate in the axis perpendicular to the beam plane. 3.2. validation of the numerical model against thermal tests fig. 8 compares the temperature-time histories at the reinforcement steel bars for all heated rc beam specimens between the numerical simulation results and the experimental tests results. reasonable correlation can be noted between the two sets of results, particularly the correlation between the maximum values of the temperature transferred from the concrete to the steel rebar. it can also be noticed from figs. (8-a) to (8-d) that the percentage of difference between experimental and numerical results in the peak temperatures at the reinforcement steel bars is about (3.56.1) % for all the heated rc beams. 3.3. validation the numerical model against the structural tests fig. 9 and table 3 compare the load-deflection relationships and the failure load respectively of rc beams between the numerical simulation results and the experimental test results. excellent agreement can be seen between the two sets of results. it can also be seen from table 3 that the maximum absolute error between the numerical and experimental results does not exceed 7%. this agreement confirms that the suggested numerical model with the associated geometrical and material modeling parameters can reasonably predict the response of the rc beam at elevated temperature up to failure. a: 250ºc b: 390ºc c: 460ºc d: 570ºc 0 25 50 75 100 125 150 175 200 0 20 40 60 80 steel-exp steel-num 0 100 200 300 400 500 600 700 0 50 100 150 200 250 300 350 steel-exp steel -abaqus 0 120 240 360 480 600 720 840 0 100 200 300 400 500 600 steel-exp steel-abaqus 0 100 200 300 400 500 600 700 0 50 100 150 200 steel-exp steel-abaqus figure 8. comparison of temperature–time histories at the reinforcement steel bars between abaqus and the experimental test results rc beams. sajida kadhem al-jasmi and, haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 251 ` a: 20ºc b: 390ºc c: 570ºc figure 9: comparison of loaddisplacement relationships of rc under different elevated temperature between abaqus and the experimental test results. table 3. compariosn of the ultimate (failur) load-temperature relationship of rc beams between abaqus and experimemental results 4. parametric study the validated numerical mode was used to conduct a parametric study to investigate the effects of two important parameters that are not investigated in the experimental test due to the limited laboratory resources. these parameters include the following: 1. effect of the high ranges of elevated temperatures 2. effect of heating rate 4.1. effect of the high ranges of elevated temperatures to investigate the effect of applying high ranges of elevated temperature on the response of rc beams, numerical simulations were carried out on rc beams subjected to three different elevated temperatures namely: 600ºc, 700ºc, and 800ºc. fig. 10 and table 4 show the numerical simulation results. figure 10: effect of high elevated temperatures on the behavior of rc beams. it can be observed from fig. 10 that when the temperature increases, the ultimate load values of rc beams decreases. the ultimate load capacity of rc beams (see fig. 10) has considerably decreased by 55.49%, 74.72%, and 81.31% compared to the control beam when exposure to temperature values of 600 ºc, 700 ºc, and 800ºc respectively. in addition, the calculated values of ductility index of rc beams for different temperature were tabulated in table 4. the results in table 4 demonstrates that the values of ductility index decreases by 8.8%, 5.88%, and 32.35% compared to the control beam when they exposed to temperature values of 600 ºc, 700 ºc, and 800ºc respectively. this reduction in the ductility can be attributed to the degradation in the mechanical properties of both concrete and steel. table 4. ductility index values of rc beam specimens. 0 25 50 75 100 125 150 175 200 0 2 4 6 8 n20-exp n20-abaqus 0 25 50 75 100 125 150 175 0 2 4 6 8 10 12 14 n390-exp n390-abaqus 0 10 20 30 40 50 60 70 80 90 100 0 2 4 6 8 10 12 14 16 18 n570-exp n570-abaqus 0 25 50 75 100 125 150 175 0 2 4 6 8 10 12 14 16 18 n700 n600 n800 n20 type of beam failure load (kn)-abaqus μ =dmax/dy n 20ºc 182 3.4 n 600ºc 81 3.1 n 700ºc 46 3.2 n 800ºc 34 2.3 type of beam failure load (kn)abaqus failure load (kn)experimental maximum absolute error (mae)% n 20ºc 182 188 3.19 n 390ºc 163 165 1.21 n 570ºc 87 82 6.09 252 sajida kadhem al-jasmi and haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 4.2. effect of heating rate fig. 11 shows the heating rates considered in this study. the first curve represents the actual heating rate corresponding to the elevated temperature of 570 ºc based on the experimental tests. the other three curves are the assumed heating rates obtained by decreasing the heating times to half the actual experimental time and increasing the heating time by two and three times the actual experimental times respectively. figure 11: heating rates used in the parametric study (t=570ºc)` fig. 12 and table 5 show the load-displacement behavior of the rc beams under different heating rates with a comparison with the results obtained from the experimental tests. it can be noted from fig. 12 that values of failure load are not considerably influenced by the change in times of temperature exposure. the ultimate load capacity has been decreased by 5.74% and 1.14 % when heating times are two times and three times the experimental exposure time respectively (see fig. 12). when the exposure time is divided to half the experimental exposure time, the values of failure load increased by 3.33% for the rc beam compared to the rc beams under actual experimental time with reducing values of vertical displacement. further, as we can see from table 5, values of ductility index decreased by 8.9%, and 11.76% when heating times are two times and three times the experimental exposure time respectively. it is noted that the ductility index for rc beams was not largely affected by the change in times of temperature exposure and even it got a slight increase by 4.95% when the actual times of temperature exposure of rc beams is divided by half. this is because the calculation of ductility index depends only on displacement of the beams. the rc beams exhibit a steeper and more linear behaviour in the ascending part of the load-displacement curve after the exposure to elevated temperature and then a quickly descended prior to failure. table 5. ductility index values of rc beam specimens. figure 12: comparison of the load-displacement responses of wrc beams under different heating rates 5. conclusions this study has suggested and validated a numerical model to simulate the behaviour and failure of rc beams under different elevated temperatures using the finite element package abaqus. a numerical model was firstly developed and validated against the results of the experimental tests conducted in this study. afterward, the validated numerical model was utilized to investigate the effect of two important parameters on the response and failure load of rc beam subjected to elevated temperature followed by static load. from the validation and parametric study results, the following conclusions can be extracted: 1. the finite element package abaqus can reasonably predict the failure and the response rc beams under elevated temperature if suitable geometrical and thermal dependent material properties are adopted. the results have indicated that using the material model with the associated reduction factors of compressive strength suggested by ec4 [3] is suitable to represent the degradation of the concrete due to elevated temperatures. 2. the failure load of rc beams is not considerably influenced by changing the heating rate. the ultimate load capacity has been decreased by 1.14 % and 5.74% when heating times are two times and three times the experimental exposure time respectively results have also shown that under the same value of temperature, the vertical displacement values for rc beams have increased when the heating rate was increased. one the other hand, when the exposure time is divided to half the experimental exposure time, the values of failure load of the rc beam increased by 3.33% compared to the rc beams under experimental time with reducing the values of vertical displacement. moreover, results have revealed that the ductility of the rc beam decreased when heating times are increases. 3. the numerical results have revealed that the ultimate load capacity rc beams has considerably decreased by 55.49%, 74.72%, and 81.31% compared to the control beam when they exposed to temperature values of 600 ºc , 700 ºc, and 800ºc respectively. 0 100 200 300 400 500 600 700 0 250 500 750 1000 1250 1500 570 2-time exposure 570 3-time exposure 570 1/2 time exposure 570 real time exposure 0 10 20 30 40 50 60 70 80 90 100 0 2 4 6 8 10 12 14 16 n570-exp n570-abaqus n570 half time exposure n570 2time exposure type of beam failure load (kn)abaqus μ =dmax/dy n 570ºc-full time exposure 87 3.23 n 570ºc-half time exposure 90 3.39 n 570ºc-2 time exposure 82 2.94 n 570ºc-3 times exposure time 86 2.85 sajida kadhem al-jasmi and, haitham al-thairy /al-qadisiyah journal for engineering sciences 12 (2019) 246–253 253 ` reference [1] yue, m.g. , yao, q.l. , wang, y.y. and li, h.n.(2008). numerical simulation on the fire proof behavior of rc beams with strand mesh and polymer mortarthe 14world conference on earthquake engineering october 12-17, 2008, beijing, china, \pp. 1-6 [2] euro code 4. (2005). design of composite steel and concrete structures–‘en 1994.part 1-2: general rules structural fire design, (august), pp. 1-109 [3] gao, w. y., chen , g. m., teng, g. j.,& dai, j. g. (2013) ‘finite element modeling of reinforced concrete beams exposed to fire’. elsevier ltd, 52, pp. 488–501. doi: 10.1016/j.engstruct.2013.03.017. [4] abaqus standard user‟s manual, volumes i-iii, version 6.8. pawtucket (america): hibbitt, karlsson & sorensen, inc.; 2008. [5] eurocode 2 (2004) 'design of concrete structures’part 1-2: general rules structural fire design euro code ss-en-1992-1-1:2008, 3(july). [6] eurocode 3 (2011) ' design of steel structures' part 1-1: general rules and rules for buildings’, en-1993-1-1:2011. march 2009 [7] ozˇbolt, j., bošnjak , j., periškic, a. s. (2013) ‘3d numerical analysis of reinforced concrete beams exposed to elevated temperature’, engineering structures (2013) , pp. 1–9. [8] iso 834-1, fire resistance tests-elements of building construction. part 1:general requirement, international organization for standardization, geneva, switzerland, 1999. [9]el-tayeb, e. h., el-metwally, s. e., askar, h. s., & yousef, a. m. (2017). thermal analysis of reinforced concrete beams and frames, hbrc journal. 132 housing and building national research center, 13(1), pp. 8–24. [10] hillerborg, a., (1985), “the theoretical basis of a method to determine the fracture energy gf of concrete”, materials and structures, vol. 18, no. 4, pp. 291-296 [19] hibbitt, karlsson, sorensen, 2010. “abaqus user‟s manual”. pawtucket, 6th edition [11] cornelissen, h., hordijk, d., reinhardt, h., (1986), “experimental determination of crack softening characteristics of normal weight and lightweight concrete”. heron, vol. 31, no. 2, delft, the netherlands [12] ceb-fip model code 90, “concrete structures” (1993). concrete structures”. thomas telford publishing. [13] aci committee. (2014). building code requirements for structure concrete and commentary aci 318m. american concrete institute, michigan. template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 278 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. evaluating the performance of asphalt rienforcement layer comprising polypropylene granules hayder salman khudhair, ass.lecturer msc., department. of civil engineering, university of kerbala, karbala, iraq e mail: hayder.salman83@gmail.com mustafa amoori kadhim, msc., department. of civil engineering., university of kerbala, karbala, iraq e mail: mostafaamore9@gmail.com abstract: despite the widespread use of hot mix asphalt (hma) overlay as one of the most important methods of pavement maintenance, rehabilitation and development of roads, also the ease and speed of implementation and low costs, there are many disadvantages and problems that accompany the use, which is mostly due to reflection of the defects of layers the old pavement on which the asphalt reinforcement layer is based. therefore, this study aims to prepare an asphalt mixture with a high performance and good specifications as overlay layer, which can resist the problems and defects that are exposed to it and increase its service life. polypropylene granules of 19 mm particles size were used as an additive to the asphalt binder (ac 60-70), with percentages 1, 2, 3, 4, 5 and 7% of the optimum asphalt content weight. the volumetric and mechanical characteristics of mixture with this addition were evaluated by using marshall stability and indirect tensile testing (its). the study showed that the use of 4% of the polypropylene granules of optimum asphalt weight gave optimal performance compared to the unmodified mix. the optimum performance of the asphalt concrete overlay during its design life, especially at high temperatures, was improved by improving the physical and mechanical properties of the asphalt mixture and by increasing its resistance to stresses is 32%. keywords: polypropylene granules, asphalt reinforcement layer, indirect tensile strength, hot mix asphalt, vertical and horizontal deformations. introduction introducing a traditional road pavement with hot asphaltic mixtures to withstand heavy vehicles axle load at high temperature is not good choice if mixture left without any addition of binder modifiers or any other techniques. the rapid growth of community may be the main cause for deteriorating of hot mixtures pavement due to increasing traffic load. numerous researchers had forced in their researches to produce a new hot mixtures that can withstand any remain in service for longer time against adverse climate and traffic conditions, such as polymer. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 279 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. polymer modified asphalt binder, this name is usually called when polymer is added to asphaltic mixtures with specific method to improve mix properties and accelerate pavement failure, and reduce reflective cracking (button and lytton, 2007). polypropylene is one of most common types of plastomers polymer that can be added to asphalt mixes to enhance performance, improve mix resistance to deformation under a wide range of varying temperatures (kalantar et al., 2012). it can be utilized by using either the dry method, which the polymer is added to aggregate before bitumen addition, or mixed with bitumen at sufficient temperature (usually not less than 170 c),the latter called wet method (khan et al., 2009). the wet process is more common method than dry process (polacco et al., 2005). awwad and shbeeb (2007) studied such type of polymer on hot mixtures using the dry process. they blended polymer with the bitumen with (6, 8, 10, 12, 14, 16 and 18%) from bitumen weight. they concluded that addition of 12% of polymer at optimum asphalt content reflected better engineering properties that untreated mixes, in term of mechanical and volumetric properties. navarro et al. (2007) revealed in their study that polymers can significantly improve the asphalt pavements performance at low, intermediate and high temperatures. they can increase the resistance of mixture to permanent deformation, thermal fracture and fatigue cracking at low temperature, decrease plastic flow and increase shear modulus at high temperature abd-a.m.al-d (2003) studied the effect of three different types of polymers with different percentages on the specifications of asphalt mixtures: high density polyethylene (hdpe) and styrene butadiene rubber. the addition of hydrate and hdpe as additives to asphalt mixtures improved their resistance of the tensile and its resistance to the impact of water. also, addition 8% of the weight of asphalt of hdpe increases the resistance of asphalt mix for the tensile strength about 38.7%. in this research polyethylene, which is one type of plastomers, has utilized using the wet process, to modify asphalt mix properties. the principle objectives of this research were to: 1enhance mixture resistance to thermal cracking. 2improve mix stability and reduce vertical and horizontal deformations. 3determination the optimum polymer content that enhance mix performance and keep other properties within the specifications, after selecting the optimum bitumen content in the mix. 1. materials • the middle values of aggregate gradation was selected for wearing layer type 3b with max size of 9.5mm as specified in the iraqi limitations (gsrb, 2003). coarse and fine aggregates were provided from local karbala quarries, and their properties are presented in table 1. figure 1 particle size distribution for wearing layer type 3b, (gsrb, 2003) 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 p e rc e n t p a ss in g ,% sieve size, mm top limit middle value lower limit al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 280 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. • ordinary portland cement (opc) was utilized as filler in this research, which was provided by karbala cement plant. • asphalt binder was provided by the doura refinery with grade (ac 40-50), its properties are presented in table 2. • polymeric materials: polypropylene was used in granules form which were prepared from local markets in karbala. it was availability, wide applications and special characteristics, particularly thermal properties. the specification and basic characteristics of the propylene granules that used in the research were determined by the manufacturer and as shown in table (3). table 1 the physical properties for filler, coarse and fine aggregate material appearance specific gravity g sb (ssd) g sb (dry) gse water absorption, % specification astm [18] coarse aggregate 2.603 2.576 2.535 2.569 2.33 c127-88 fine aggregate 2.692 2.663 2.647 2.670 0.50 c128-97 filler 2.720 2.720 c128-97 los-angeles abrasion, % 33 < 35 c131-96 sand equivalent, % 63 >50 d2419-95 table 2 properties of asphalt binder property test values astm designation acceptable limit penetration,100 gm. ,25 ͦ c,5sec (1/10 mm) 43 d5 (astm, 2015b) 40-50 specific gravity, 25 ͦ c (gm./cm3) 1.03 d70 (astm, 2009) 1.02-1.04 ductility, 25 ͦc, 5 cm/min (cm) >100 d113 (astm, 2007) >100 flash point, (ͦ c) 318 d92 (astm, 2005) >240 softening point ( ͦc) 47 d36 (astm, 2000) 40-50 loss of weight50gm,163°c,5h 0.248 d 1754 (astm, 2014) ≤ 0.80 table 3 properties of polypropylene polymer properties specification value astm [18] melt flow index, gr/10min d1238 10 density, gr/cm^3 d1505 0.943 softening point, °c d1525b 135 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 281 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 2. experimental program: design asphalt mixture and effect of addition of polypropylene granules on the properties of asphalt mixtures marshall test design method is considered common method for determining amount of required bitumen in the mixture that reflected best mechanical and volumetric properties, as will be clarified later. the study will include design of reference mixture without polymer for comparison and to clear effect of polymer. 2.1. design of the reference asphalt mixture the asphalt mixture was designed according to marshall's design method (astm, 2015a). six percentages of asphalt (4, 4.5, 5, 5.5, 6 and 6.5) were added as a percentage of the weight of the asphalt mixture. then, volumetric properties and marshall test were determined for each percentage to select the optimum percentage of asphalt content. the selected percentage must meet the design requirements of marshall method. the following tables describes marshall stability and flow result (table 4) and the volumetric properties results (table 4 and 5): table 4 marshall stability (ms) and marshall flow (mf) of asphalt mixture with the different percentage of asphalt av. flow (mm) flow (mm) av. cor. ms (kn) cor. ms (kn) ms (kn) cor. factor height of specimen (mm) asphalt )%( 2.57 2.70 10.37 9.85 8.64 1.14 58.2 4 2.55 9.70 9.33 1.04 61.0 2.45 11.58 11.58 1.00 0.26 2.57 2.90 14.02 13.98 13.98 1.00 63.0 4.5 2.80 14.54 13.98 1.04 61.5 3.05 13.54 13.54 1.00 64.0 3.38 3.30 13.19 13.17 15.31 0.86 70.0 5 3.40 15.24 13.37 1.14 59.0 3.45 11.15 12.52 0.89 68.0 3.65 3.65 9.58 7.20 8.09 0.89 67.5 5.5 3.60 10.77 12.53 0.86 70.0 3.70 10.77 13.29 0.81 73.5 4.63 4.60 8.93 9.78 10.19 0.96 65.0 0 4.50 8.20 8.20 1.00 63.0 4.80 8.80 8.80 1.00 63.5 5.93 6.05 6.98 6.36 8.16 0.78 74.5 6.5 5.95 5.78 6.49 0.89 67.0 5.80 8.81 9.48 0.93 66.5 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 282 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. table 5 properties of asphalt mixture with the different percentage of asphalt content av. air void )%( air void )%( gmm av.gmb gmb specimen asphalt (%) 8.09 6.67 2.459 2.260 2.294 a01 4 9.13 2.459 2.234 a02 8.46 2.459 2.251 a03 5.08 4.37 2.431 2.307 2.325 a11 425 4.89 2.431 2.312 a12 5.99 2.431 2.285 a13 3.80 2.83 2.408 2.317 2.340 a21 5 3.64 2.408 2.32o a22 4.92 2.408 2.290 a23 2.00 1.99 2.385 2.337 2.338 a31 5.5 2.44 2.385 2.327 a32 1.57 2.385 2.348 a33 1.17 1.11 2.382 2.354 2.355 a41 0 1.58 2.382 2.344 a42 0.82 2.382 2.362 a43 1.14 1.02 2.375 2.348 2.351 a51 6.5 1.02 2.375 2.351 a52 1.36 2.375 2.343 a53 table 6 volumetric properties of the trial asphalt mixtures av.v.f.a, (%) v.f.a, (%) av. v.m.a )%( v.m.a, )%( % passing gsb specimen asphalt (%) 50.61 55.56 16.30 15.01 96.00 2.592 a01 4.0 47.09 17.25 96.00 2.592 a02 49.17 16.64 96.00 2.592 a03 66.21 69.55 14.98 14.34 95.50 2.592 a11 4.5 66.99 14.81 95.50 2.592 a12 62.08 15.80 95.50 2.592 a13 75.04 80.13 15.08 14.23 95.00 2.592 a21 5.0 75.62 14.95 95.00 2.592 a22 69.37 16.08 95.00 2.592 a23 86.50 86.54 14.77 14.76 94.5 2.592 a31 5.5 83.88 15.16 94.5 2.592 a32 al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 283 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 89.09 14.40 94.5 2.592 a33 92.06 92.42 14.63 14.58 94.00 2.592 a41 6.0 89.48 14.98 94.00 2.592 a42 94.28 14.33 94.00 2.592 a43 92.58 93.26 15.28 15.19 93.50 2.592 a51 6.5 93.28 15.19 93.50 2.592 a52 91.19 15.48 93.50 2.592 a53 after determining the properties of marshall, the relationship between the added asphalt ratio and each of the characteristics given by the marshall test was measured (marshall stability, marshall flow, volumetric weight, air void, v.m.a, v.f.a) (1, 2, 3, 4, 5, 6) respectively, and by studying and analysing the resulting curves in the previous forms we find that: 1. figure 2 shows that the value of marshall stability increases by increasing the percentage of asphalt to reach a maximum stability value, after which the stability value tends to decrease with the increase of the asphalt percentage. this explains that when the asphalt percentage is low, the cohesion between the coarse and fine aggregates is weak, asphalt, which plays the role of the bonding material, becomes more cohesive until reaching the maximum value of stability. the value of stability decreases after the added asphalt percentage becomes large. this reduces the cohesion between the coarse and fine aggregates and facilitates their sliding on one another which causes the grains to float in the asphalt. leads to a reduction in the value of the marshall stability. 2. in figure 3, it can be noticed that the value of the flow increases with the increase of the added asphalt percentage. this is explained by the increase in the percentage of added asphalt which facilitates the movement of the coarse and fine aggregates in the asphalt mixture and reduces the friction between them. consequently, increasing the usability of slippage which increases the flow values. 3. figure 4 shows that the volumetric weight expressed by the volumetric density of the asphalt mix increases with the percentage of asphalt until the curve reaches a maximum value. after this value, the volumetric weight decreases with the increase in the asphalt percentage. which is due to increase the percentage of asphalt less the friction between the coarse and fine aggregate and easy to slip and move between them, which increases the effectiveness of the compaction. consequently, increases the density of the asphalt mixture and continues this effect with increasing the percentage until it reaches to optimum value then plays the increase in the percentage of asphalt reverse role, leading to the spacing between grains, increase spaces and the lack of effective compaction, which leads to a decrease in the value of the volumetric weight and thus the volume density. 4. figure 5 shows that the percentage of air void in the asphalt mix decreases with the increase in the asphalt percentage. this is due to the fact that the added asphalt is a part of it absorbed by the coarse and fine aggregate and fillers and its quantity is related to granular composition of the filler of the mixture. whereas, the remaining asphalt, leads to coating the coarse and fine aggregate, and filler and performed the main function of asphalt as bonding of asphalt mixture. performs the main asphalt function as a bonding material in the asphalt mixture, this part is called effective asphalt. consequently, the increase in the asphalt content from the amount absorbed by the coarse and fine aggregates, filler and the required amount for coating the coarse and fine aggregates the coarse and fine aggregates which form an excess amount of asphalt will be formed to fill the remaining space between the coarse and fine aggregate coated with asphalt, thus reducing the percentage of air voids in the asphalt mix. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 284 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 5. figure 5 shows that the percentage of v.m.a in the asphalt mix decreases with the increase of the added asphalt percentage until reaching a small value for the percentage of v.m.a. v.m.a begins to increase with the increase of asphalt. because, the asphalt helps to easy slipping the coarse and fine aggregate and fillers on each other. increases the percentage of asphalt increases the effectiveness of compaction and the density of the asphalt mixture thus reduce the percentage of v.m.a, even reaching to the percentage that plays opposite role. which, reduces the effectiveness of the compaction and thus mix asphalt density decreases and increases the percentage of voids between the coarse aggregate and fine materials and fillers in the asphalt mixture. 6. figure 6 shows that the percentage of v.f.a increases with the increase in the percentage of added asphalt and curved asphalt as opposed to the curve formed from the ratio of the asphalt percentage with the air void in the asphalt mixture. this is due to the same discussion of figure 5. figure 2 the relationship between marshall stability and asphalt content figure 3 the relationship between marshall flow (mf) and asphalt content% 10.37 14.02 13.19 9.58 8.93 6.98 0 2 4 6 8 10 12 14 16 4 4.5 5 5.5 6 6.5 7 s ta b il it y , k n % asphalt 2.57 2.92 3.38 3.65 4.63 5.93 0 1 2 3 4 5 6 7 4 4.5 5 5.5 6 6.5 7 f lo w , 1 /1 0 m m % asphalt al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 285 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 4 : the relationship between asphalt content% and volumetric specific gravity (gmb) figure 5 the relationship between % asphalt and air void content figure 6 the relationship between % asphalt and v.m.a 2.26 2.307 2.317 2.337 2.354 2.348 2.24 2.26 2.28 2.3 2.32 2.34 2.36 4 4.5 5 5.5 6 6.5 7 g m b asphalt content,% 8.09 5.08 3.8 2 1.17 1.14 0 1 2 3 4 5 6 7 8 9 4 4.5 5 5.5 6 6.5 7 a ir v o id % % asphalt 16.3 14.98 15.08 14.77 14.63 15.28 14.4 14.6 14.8 15 15.2 15.4 15.6 15.8 16 16.2 16.4 4 4.5 5 5.5 6 6.5 7 v .m . a (% ) asphalt content,% al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 286 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 7 the relationship between % asphalt and v.f.a 7. based on the previous figures, the percentage of (52.5%) of the asphalt mixture was adopted as the optimum percentage that achieves the best values for the physical and mechanical properties of the asphalt mix. the selected percentage was within limitations of the iraqi gsrb standards and reflected higher stability based on marshall design method for surface asphalt layer. the properties of the reference asphalt mix for the optimum asphalt percentage are shown in table (7). table 7 properties of reference asphalt mixture compared with gsrb limitations gsrb value properties 3-7 5.13 % optimum asphalt content ≥8 13.8 marshall stability, kn 2 – 4 5 marshall flow, mm 2.319 (gmb) 3 – 5 4.14 air void, % ≥ 14 14.91 v.m.a, % >70 72.9 v.f.a, % 2.2. effect of addition of polypropylene granules on the properties of asphalt mixtures the effect of the addition of polypropylene granules on the properties of asphalt mixtures was studied by adding them to the asphalt binder in different percentages (1, 2, 3,4,5,7%) of the weight of the asphalt. the wet process was followed for mixing the polymer with the bituemn (at optimum bitumen content). the method was achived by blending the polymer and the bitumen at temperture not less than 150c for 2hr to ensure mixture momogenitiy using high speed rotary mechnie mixer. the higher temperature of mixing facilities mixing process through reducing bitumen viscosity, and sufficient particles melting of the used polymer.then, forming samples of the modified asphalt mixture in the previous proportions by three samples at least for each percentage of additive and take the mean value and compare it with unmodified samples with granules, depending on the characteristics given by the indirect tensile resistance test, and determine the best proportion of granules that gives better improvement in the properties of the asphalt mix. 2.2.1 indirect tensile strength test (its) the indirect tensile strength test was performed based on (astm, 2012), and the determination of both the indirect tensile strength and the horizontal and vertical flow of the modified samples were made with 50.61 66.21 75.04 86.5 92.06 92.58 0 10 20 30 40 50 60 70 80 90 100 4 4.5 5 5.5 6 6.5 7 v .f .a ,% % asphalt al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 287 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. polypropylene granules for each percentage of the added granules as shown in table 8. the values of the physical properties of the asphalt mixture including indirect tensile test samples as shown in table (9) volumetric weight, percentage of air spaces, percentage of coarse,fine aggregates, filler, percentage of asphalt-filled spaces. table 8 properties of its test of different percentage of polymer av. vertical flow vertical flow (mm) av. flow (mm) flow (mm) av. i.t.s (kpa) i.t.s (kpa ) load, p (n) spec. poly mer %) ) .2.1 .2.6 .246 .246 5.1256 5642.. 5445 1 6 .216 .256 5412.. 5551 2 .266 .5256 56625. 5... 3 .21. .255 .251 .206 55.2.5 55.2.. 5.1. 4 . .216 .256 54.26. 5054 5 .2.6 .2.6 5..201 555. 6 .205 .255 .2.1 .2.6 50125. 066254 045. 7 . .215 .246 54.204 50.4 8 .206 .256 55.2.1 0515 9 .251 .206 .2.5 .2.6 05526. 0..211 00.. 10 5 .205 .246 0.52.4 0515 11 .245 .2.6 0052.5 1.5. 12 .24. .256 .2.6 .266 0..26. 0.424. 1461 13 4 .255 .2.6 0.12.. 1545 14 .246 .2.6 0552.5 0.4. 15 .255 .256 .266 .266 1.42.. 1.02.. 15.5 16 5 .25. .2.6 1.4251 1116 17 .251 .2.6 1..2.1 1161 18 .2.6 .2.6 .256 .206 15.260 1.02.. 1500 19 1 .256 .246 14.2.6 .6.5 20 .2.6 .256 1..2.. 1455 21 the indirect tensile strength test shows that the addition of polypropylene granules has improved the properties of asphalt mixtures. this improvement in properties is shown by the following figures: 1effect on indirect tensile strength: as shown in fig. 8, the indirect tensile strength of the asphalt mix is generally increased with the increase in the percentage of the added polypropylene granules, where the increase in resistance is weak in the few percentages of the granules and the effective effect begins for polypropylene granules on tensile strength after 2% of the addition, which increases about 32% higher than the reference mixture at percentages 4% of the addition. then effect of the granules on improving the resistance of the indirect tensile strength decreased by 4% of the addition, after which the granule effect improved. indirect tensile strength. this is explained by the fact that with the addition of polypropylene granules to the asphalt binder, it changes its chemical composition to form a homogeneous mixture with greater adhesion properties which increases the cohesion of the asphalt mixtures and thus increases its resistance to stresses. 2influence on horizontal and vertical deformation: both horizontal and vertical deformation reflect the plastic deformation of the test samples at failure in both the vertical direction on the loading axis and the parallel direction of the loading axis respectively, as shown in figure 9, which explicates the relationship between granules added ,and figure 10 expressing the relationship of the vertical deformation with the ratio of the added granules, both horizontal and vertical deformation decrease with increasing percentage of polypropylene granules. this is explained by increasing the hardness and hardness of the asphalt binder with increase of granules in asphalt that reduces the flexibility and thus reduces the horizontal and vertical flow values. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 288 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 8 the relationship between polymer content% and its figure 9 the relationship between polymer content and horizontal deformation of its figure 10 the relationship between polymer content% and vertical deformation of its 517.3 538.83 567.31 633.02 682.08 714.22 731.06 400 450 500 550 600 650 700 750 0 1 2 3 4 5 6 7 8 it s ( k p a ) %contentpolymer 2.400 2.370 2.270 2.230 2.100 2.000 1.500 0 0.5 1 1.5 2 2.5 3 0 1 2 3 4 5 6 7 8 h o ri zo n ta l d e fo rm a ti o n ( m m ) %polymer content 1.870 1.720 1.630 1.570 1.420 1.330 1.200 0 0.5 1 1.5 2 0 1 2 3 4 5 6 7 8 v e rt ic a l d e fo rm a ti o n ( m m ) %contentpolymer al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 289 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 2.2.2 effect of polymer on hma volumetric properties volumetric properties : the maximum theoretical density results from fig 11 clarifies that significant reduction in the values with increasing polymer content in the mix, and this may backs to polymer specific density, which is lower than bitumen density as clarifed in fig 11. also, a slight noticeable increase in the air voids content has been noticed with increasing amount of the polymer content. all av% values were within the limitation (between 3-5). further, from fig 12, addition of polymer has increased vma%, because of higher air voids content. also, all the percentage are within the gsrb limitation (above 14%) as cleared in figure 13. fig 14 present the relation between polymer content and vfb%. increasing amount of polymer resulted in sufficient negative change on vfb% values. the polymer content up to 4% reflected vfb% within the limitations (<70). returning to the design requirements of the asphalt mixture as demonstrated in table 5, the changes in the properties of asphalt mixtures due to the addition of polypropylene granules remained within the permissible limits. therefore, the best percentage of granules added is the percentage that improves all or most mechanical properties of asphalt mixtures. as a result of the study and analysis of the results of the indirect tensile strength test, it has been concluded that addition of 4% of the polypropylene granules is the best percentage that gives optimal improvement and effective of the different properties of the asphalt mixture. the selected percentage was efficient to enhance the mechanical properties of the test program and reducing vertical and horizontal deformations, without effecting other volumetric and mechanical properties and makes them out of the limitations. figure 11 the relationship between polymer content and gmb 2.341 2.339 2.335 2.331 2.324 2.318 2.307 2.305 2.31 2.315 2.32 2.325 2.33 2.335 2.34 2.345 0 1 2 3 4 5 6 7 8 g m b %polymer al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 290 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure 12 the relationship between polymer content and air void figure 13 the relationship between polymer content and v.m.a figure 14 the relationship between polymer content and v.f.a 4 3.97 3.96 4.02 4.26 4.52 4.89 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 a ir v o id ( % ) %polymer 13.99 14.07 14.22 14.38 14.64 14.87 15.26 13.8 14 14.2 14.4 14.6 14.8 15 15.2 15.4 0 1 2 3 4 5 6 7 8 v .m .a ( % ) %polymer 71.46 71.79 72.14 72.06 70.95 69.64 67.95 67 68 69 70 71 72 73 0 1 2 3 4 5 6 7 8 v .f .a ( % ) %polymer al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 291 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. conclusions based on previous analysis of figures, the main conclusions can be drawn: 1polymer modified asphalt method showed higher mechanical performance than the control mixtures. 2increasing amount of polymer content within hma mix resulted in its enhancement , for all studied percentages of the induced polymer. 3polymer has increased mixture strength by reducing vertical and horizontal deformations further to increasing its strength. 4polypropylene granules showed negative effect on hma volumetric properties. increasing amount of polymer has increased voids in mineral aggregates and air voids content, and reducing density and voids filled with bitumen. 5the optimum percentage of polymer content was 4% based on the mechanical and volumetric properties, since other volumetric properties like vfb% showed values out of the standards (70-85%) at higher polymer content than 4%. references 1. abd-a.m.al-d, i. 2003. evaluation of the factors influencing thetensile properties of asphalt paving materials. 2. astm 2000. standard test method for softening point of bitumen (ring-and-ball apparatus). d36, american society for testing material, west conshohocken, pa, united states. 3. astm 2005. standard test method for flash and fire points by cleveland open cup tester d92, american society for testing material, west conshohocken, pa, united states. 4. astm 2007. standard test method for ductility of bituminous materials. d113, american society for testing material, west conshohocken, pa, united states. 5. astm 2009. standard test method for density of semi-solid bituminous materials (pycnometer method). d70, american society for testing material, west conshohocken, pa, united states. 6. astm 2012. standard test method for indirect tensile (idt) strength of bituminous mixtures. d6931, american society for testing material, west conshohocken, pa 19428-2959, united states. 7. astm 2014. standard test method for effects of heat and air on asphaltic materials (thin-film oven test). d1754, american society for testing material, west conshohocken, pa, united states. 8. astm 2015a. standard test method for marshall stability and flow of asphalt mixtures. d6927, american society for testing material, west conshohocken, pa, united states. 9. astm 2015b. standard test method for penetration of bituminous materials. d5, american society for testing material, west conshohocken, pa, united states. 10. awwad, m. t. & shbeeb, l. 2007. the use of polyethylene in hot asphalt mixtures. american journal of applied sciences, 4, 390-396. 11. button, j. & lytton, r. 2007. guidelines for using geosynthetics with hot-mix asphalt overlays to reduce reflective cracking. transportation research record: journal of the transportation research board, 111-119. 12. gsrb 2003. general specification for roads and bridges,section r9. iraq. 13. kalantar, z. n., karim, m. r. & mahrez, a. 2012. a review of using waste and virgin polymer in pavement. construction and building materials, 33, 55-62. al-qadisiyah journal for engineering sciences vol. 11, no. 2 issn: 1998-4456 page 292 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 14. khan, t. a., sharma, d. & sharma, b. 2009. performance evaluation of waste plastic/polymer modified bituminous concrete mixes. 15. navarro, f., partal, p., martínez‐boza, f. & gallegos, c. 2007. influence of processing conditions on the rheological behavior of crumb tire rubber‐modified bitumen. journal of applied polymer science, 104, 1683-1691. 16. polacco, g., berlincioni, s., biondi, d., stastna, j. & zanzotto, l. 2005. asphalt modification with different polyethylene-based polymers. european polymer journal, 41, 2831-2844. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٢ the advantages of prgrammable logic controllers in industries muhanad dhiya hashim , al qadisiya university – collage of engineering abstract in the industrial world the computers and microprocessors have become popular for use in automatic control systems, thus we have a new generation of control systems which is called programmable logic controller . these systems has plenty of control components (timers, counters, registers, comparator, clock, …)inside the software of the plc instead of the classical components , and the contacts of the relay ( normal open and normal close ) have been replaced by the orders which are saved in memory. the updating and modification of the system is easy to obtain by rewriting the program.another advantage of the plc is that the input of the plc is photo isolated and shielded , but the most important advantage is that we can test the program befor it's using in the machine by using the simulator which is included with the plc program . keyword: programmable logic controller , ladder language , function black diagram , structured text , insturction list , secquential function chart . ������� �� ���� ������ ������ ����� p�ء ه��q � (�����o ه/��r آ��0�ء–(0/ rد���� ا r�)�o–r�� آ��r أ 0/ ������ $�" ��( 1��� �"��� � )��������9� >� �� !e�"� )* !����� ��"��0�� � � ��������� > �3�+� l�5 !��39� � ��+� )* !em�"� '� ���">� �� e���� )�� � h����� )6%��� >� �� !e�"� ��+� )�� � )��������9� ���;� �m�� ���3 �m� :�� � �mmm >� �� ����� '� ���� �� ) ���/4�� . � � �0� . = e9� ��"+� . �����6�� . ��/��� �����.(..... 1��m�� ������� ��mmmmm+��� +� =�e3� �� �;� ��� ���+ >� � �� ������ '� �����+n� ������� ��� o��� ��� �6�mm �m�� )�� > �� )* ����3�+� �6��+m ����6� !�%�+� ��. '� h������ =���� !���;� 1�� � 7��+� '� $�+� g��� !������ h������ $��0� � � >�� '� '��� . � �+3� $��6� >� >� �� ������ � ) �,� $e0�� ="���� . ���" � �� !em�"� '+ mmmmm> � )m6%�� e�m�"� ��m�"��� km� 7*��� )�� �� 7��% '� =���5� $�/ =������� 2�mmmm3� h������ 2 * =������ �� h����� m���� �� $%� $�� =�� )* 1���� h������ ����� 7��% '� =���� :� =� e� �� =*�,� ������;� g��� 1����m !��m�� �� '� h������ $�� � h������ =���� =���� �0� %��mmm,� 2�/ ��� 'e3�� h������ $�3. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٣ introduction plcs are used in many different industries and machines such as conveyor systems , food processing machinery (e.g filling bottles with water or juice) , auto assembly ( e.g auto industry ), fluid level control ( e.g water tanks ) , mixing fluids (e.g paint industries) , motor speed control (sanjeey gupta &sc sharma, 2005 ) . well known plc brands are allen-bradley , mitsubishi-electric , abb ltd, honeywell , siemens , modicon , omron , general electric , square-d (telemecanique ) and panasonic (a brand name of matsushita ) , less known plcs that are programmable in basic are available from cubloc( com file technology ) or tri-plc ( traingle research int. ) ( nebojsa matic , 2001 plc encyclopedia plc references , 2004 ) . the primary reason for designing the plcs is to eliminate the large cost involved in replacing the complicated relay based machine control systems . the first plc which is used in commercial production was named modicon – 084 proposed by bedford associates , then other companies proposed computer based schemes (pdp-8 ) . when production requirements changed so did the control systems , this becomes very expensive when the change is frequent. the plcs had to be : * easily programmed by maintenance and plant engineers. * the lifetime must be long . * the programming changes easily performed. * the use of programming technique ( that replace mechanical parts with solid-state once) . * the use of microprocessors and cpu units . * can send and receive varying voltages to allow us to enter the analog world. ( mohammad aqil , 2007 nebojsa matic , 2001 – imad alsai'ad , 2005) . the program is a chain of instructions held in order to control the working procedure of a machine or a system, writing the instruction of the program will be held by one of the languages especially made to the plc ' by using the programs especially made to the plc according to the manufacturing company , there are five basic languages : 1) function block diagram ( fbd ) . 2) ladder language ( ld ) . 3) structured text (st -similar to pascal programming ) . 4) instruction list ( il) . 5) sequential function charts ( sfc ). ( lipsky .kevin , 1990 plc languages ) after the writing of the program in one of the languages we sent this program from the personal computer to the memory in the plc , this procedure contains translating the instructions to the machine al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٤ language by using the compiler listed with software of the plc. the language which is used in this research is ladder language ( ladder logic training series , www.automation nc .com ) . experimental validation in this item we will consider zelio sr1-b201bd ( plc ) by telemecanique : 1) from edit menu we select the zelio mode , in this menu we can choose the language ( ladder ) and logic inputs { 12 separate inputs } , output { 8 outputs every output has 4 conditions ( q contactor , q remote control , sq set , rqreset )} , intermediate cell , timers , counters , analog inputs , clock , text element . 2) from edit menu we select the free mode ,in this menu we can choose the program , parameters , simulation . 3) transfer menu: in this menu we can choose pcmodul {downloading program from pc to plc } , modul – pc ( downloading program from plc to pc ) , run modul ( run the plc ) , stopmodul (stop plc ) . 4) mode menu: in this mode we can choose on line monitoring mode( here the plc is connected to the pc through the programming cable we can watch the performance of the plc through the screen of the computer, editing mode ( when we want to disconnect the plc from the pc ) . case study : a juice machine which works totally mechanical and we need to modify it so the control system will be electrical , since relays , limit swiches are mechanical devices they also have a limited lifetime which required adequate maintenance schedules, troubleshooting was also quite tedious when so many relays are involved , also the size is important and the initial wiring.the machine shown in ( fig . 1 ) that works during the week { from saturday to thursday }and the working time is form 8:00 to 13:00 and from 13:30 to 16:00 . the machine wash a bottle with water through valve v1(opens for 2 sec ) ,then the machine full the bottle with juice through valvev2 ( opens for 4 sec ), for each valve there is a sensor (s1) , (s2) respectively , after counting 12 botlles the machine stops ? working procedure when the bottle is at point a (figure 1) and we press the start switch the motor now will work , when the bottle reach the sensor s1 the motor will stop and the valve v1 will work for a period (2 sec ) then the motor will work until the bottle reach sensor s2 then the motor will stop again and valve v2 will work for a period ( 4 sec ) then the motor will work , and so on…… the electrical and plc wiring is shown in (figure 2). logic form (motor = 1) ….. {( start=1) anda ( s1=1 ) anda ( s2=1 )} or {( start = 1) and ( tw1.out =1 ) and ( s1= 1 )} or {( start =1) and ( tw2.out =1 ) and ( s2=1 )}. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٥ ( motor = 0)….. ( start=0) or {( start = 1) and ( s1=1) and ( tb1.out =1)} or {( start =1) and (s2 = 1 ) and ( tb2.out =1 )} . the ladder diagram will be as in figure 3 . now if we would like to control the switching time of the machine during the week ( from saturday to thursday ) so that the working time begins ( 8:00 ) until (13:00 ) and form ( 13:30 ) until ( 16:00 ) so we must activate the clock from the tool bar ( edition ) of zelio , here we have four channels (canal a,b,c,d ) as in the window below, by turning the power on ( on) the zelio plc will run every day except friday as in ( figure 4 ) . so if we have an emergency case or we need to stop the machine all we have to push the button ( halt ) as in ( figure 5 ) .the ladder diagram will be the same as fig . 3 but it will have additions as in ( figure 6 ) . now if we need the machine to stop after counting 12 bottles ( figure 6 ) ,we have to add a counter ( up ) fixed on ( 12 ) and sensor( s3 ) , the machine will start if we press the start and it will stop at sensor s1 for (2 sec.) then it will run until it reach sensor s2 the motor will stop for ( 4 sec. ) and the motor will run again until the counter counts ( 12 ) bottles and the motor will stop after that so the worker can remove the package of a dozen of bottles , then he will start the machine again ( figure 7 ). logic form (motor = 1) ….. {( start=1) anda ( s1=1 ) anda ( s2=1 )} or {( start = 1) and ( tw1.out =1 ) and ( s1= 1 )} or {( start =1) and ( tw2.out =1 ) and ( s2=1 )} or {( start = 1 ) anda ( counter. out =1 ) anda ( stop = 1 )} . (motor = 0) ….. ( start=0) or {( start = 1) and ( s1=1) and ( tb1.out =1)} or {( start =1) and (s2 = 1 ) and ( tb2.out =1 )} or ( counter = 1 ) . the total electrical wiring will be as in ( figure 8 ) and ladder diagram as in ( figure 9 ) . results and discussion by using plc we have minimized the large number of electrical components (timers ,counters , clock) which can be used in the control panels and maintenance time and increase the life time of machine and the speed of processing ( using cpu ) so if we need to add or modify the procedure of work all we need is to rewrite the program in its new form in one of the languages of programming and reload it to plc by using personal computer while the old method ( using electrical components) needs to modify the control panel ( adding new components and new design ) which will add extra costs and extra time . conclusion 1. by using the plcs we can have an adequate design to install the control components, time of installion, time of modification, time of maintenance. 2. all kinds of plcs have the same procedure of work but they don’t have the same number of component which contains, type , reading – writing speed , response speed , number of inputs – outputs , number of jobs which plc can operate , capacity so the user must know the specification of these types in order to choose the adequate plc . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٦ 3.the classical structure ( hardwire logic ) is based on different kinds of component ( wires , timers , counters ) and it’s a solid state and inflexible and has many disadvantages such as repairing a control panel which can take a lot of time to find the broken part and even it take a lot of money, when we need to modificate the procedure of the machine. 4. in order to change the procedure of a machine we have to renew the program ( adding timers , counters and other applications which can the plc apply ) . 5. the plc s are designed to a different industrial overloads and temperature and they are protected from jamming , and against short circuit. 6. in case of program overloaded we can recharge the program( loaded on a cd ) from the pc to our plc by using the transfer – pc module in the tool bar of the device . 7. we can test the program before installing the plc on position by using the simulator( which is placed in edition mode free mode in the tool bar of the device ) enclosed with the plc. 8. this kind of plcs called ( compact ) and there are two kinds of plcs more ( modular, intermediate ) but this kind has the advantage in case we have several machines so if one machine is out of order there is no need to stop all the machines only the broken one , and this kind of plcs has the ability to add local expansion which incraes the number of inputs and outputs without the need to buy a new plc , also we can connect this kind of many of these plcs with our pc or with an external mointer through the net input . references 1. fundamentals of plc final ( www.4 shared . com/plc p.23 . ). 2. introduction to plc controllers by nebojsa matic (www. mikro .com/en/books/plc book/plc book.htm ) . 3. introduction to plcladder logic part 1 ( www.4share .com/ plc / page 22) . 4. ladder logic training series [ automation technology inc. harrisburg. nc (www.automationnc .com ) 5. plc languages ( www. kronotech.com/plc/languages.htm) .. 6. plc references [ journal of manufacturing systems (november 1 2004 ) ] . 7. plc (imad alsai'ad & samir halawa , al – ulum center 2005 – syria ) . 8. programming plc ( high technology training module) by lipsky , kevin [ eric – education resource information center (may 1990 wisconsin indianhead technical college)] . 9. programmable logic controller product research ( novmber 2006 ) .. 10. programmable logic controllers [ carbide & tool journal ( www.allaboutcircuits.com/ vol_4/ chpt_6/6 .html ) ] . 11. programmable logic controllers itce–introduction to plcs chapter 1 by mohammad aqil [ al-azhar university – faculty of engineering & information technology 2007 ] . 12. selection and application of advancedcontrol systems :plc, cd and pc – based system by sanjeey gupta &sc sharma( journal of scientific industrial research volume 64 number 4 april 2005 ) . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٧ figure1 figure 2 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٨ figure 3 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٩ figure 4 figure 5 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٤٠ figure 6 figure 7 figure 8 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٤١ figure 9 template for academica science journal al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 357 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. synthesis and characterization of unsupported catalyst for gas oil desulfurization mohammad f. abid*, mohammed a. hamza*1, shakir m. ahmed2, salah m. ali3, sattar j. hussein4 (*)department of chemical engineering, university of technology, baghdad, iraq. e-mail: 80005@uotechnology.edu.iq (*1)department of chemical engineering, university of technology, baghdad, iraq. e-mail: m.alshmary35@@gmail.com (2)scop, ministry of oil, baghdad, iraq. e-mail: shakir58scop@gmail.com (3)petroleum research and development center, ministry of oil, baghdad, iraq. e-mail: salah56ali@yahoo.com (4)petroleum research and development center, ministry of oil, baghdad, iraq. e-mail: sattarjaleel@yahoo.com abstract: unsupported mos2 catalysts were synthesized for the hydrodesulfurization (hds) of real feed gas oil using different temperatures and pressures. hydrothermal method was utilized to prepare by using molybdenum trioxide and sodium sulfide. the characterization of the catalyst was identified by xrd, sem, and bet techniques. it was found that bet surface and pore volume were positively affected by pressure and temperature that could improve the activity of mos2. kinetic analysis showed that hds reaction over mos2 follow pseudo-first order kinetics. experimental results revealed that the hds activity of the unsupported mos2 catalyst was better than supported como/al2o3 catalyst under the same operating conditions. keywords: unsupported catalyst; middle distillates; hydrodesulfurization; hydrothermal method; catalyst activity. mailto:shakir58scop@gmail.com mailto:sattarjaleel@yahoo.com al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 358 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 1. introduction recently, the request of fuel has been rising highly due to increase of automobile engines. however, the environmental regulation laws require motor fuels of low sulfur content which needs efficient and feasible hydrodesulfurization process. consequently, petroleum refineries pay more attention to lower sulfur level in their products. the synthesis of new catalysts and utilizing modern refineries is the most acceptable solution to attain lowest sulfur levels.most of the classical catalysts utilize in the hydrodesulfurization reactions are comos2, mos2 or nimos2 supported on alumina (girgis and gates, 1991; speight and ozum, 2001). in 2001, a new type of catalyst is synthesized in the market which is the unsupported catalyst (eijsbouts et al., 2007). such catalysts have higher concentration of active sites per unit surface area of the catalyst, thus offer more activity than supported catalysts. consequently, the synthesis of new unsupported sulfided catalyst appears to be a good required research trend. improvement of catalyst activity depends on knowing the connection between the active sites and the framework of mos2 and mos2 catalysts. although some published data have notified the framework-activity connections for mos2 and comos2 catalysts, they essentially concentrated upon the hds process (hensen et al., 2001; schweiger et al., 2002). these reports have depicted that the catalytic performance is quite related to the rims of the levels of the mos2 layers, and particularly with the sulfur-free places that are created over the rim sites. many methods have emerged to synthesize mos2 or comos2 with controlled surface-characteristics, such as solvothermal (duphil et al., 2002), sonochemical (dhas and suslick, 2005) or biotemplate (chang et al., 2006) syntheses. théodet (2010) indicated that the activity of supported catalyst would be decreased due to the interference effect of the support with the active phase. additionally, the concentration of active sites per unit volume is decreased thus high amounts of catalysts are required to attain the wanted fuel properties. the author depicted that bulk catalysts are the “wave of the future” in many industrial applications. avarez et al. (2008) prepared unsupported nimos2 catalyst from ammonium and c16h37no, (nh₄)₂mos₄ fattened with ni(no3)2.authors depicted that the alkyl group in the c16h37no precursor had a direct effect on surfacecharacteristics of catalyst. the extent of the alkyl concatenation from c1 to c4 showed a very high hds activity. gaojun et al. (2010) prepared bulk ni-mo-s2 catalyst. their outcomes depicted that the bulk nimo catalyst has excellent hydrogenation performance to produce fuel with sulfur content ≤ 10 ppm. he and que (2016) provided a thorough review of the bulk mos2, briefing updated studies on framework, characteristics, preparation methods. the main aim of this study was to prepare and identify an unsupported catalyst (e.g., mos2). the other objective was to evaluate the performance of mos2 catalyst for hds process of gas oil. 2. experimental work 2.1 materials molybdenum oxide, (moo3, 99.5 wt%) was purchased from merck. sodium sulfide (na2s) (purity 62 wt%) was purchased from hrd, germany. hcl (36 wt%) and ethanol (99.5 wt%) were obtained from cdh, india. gas oil was obtained from al-daura refinery, baghdad. properties of (gas oil) utilized in the present study was shown in table (1). table (1): properties of gas oil (al-daura refinery, baghdad) property value api @15.6 0c 40.1 sp.gr@ 15.6 0c 0.8246 sulfur content (ppm) 4940 cetane number 51 distilled (vol.%) in crude oil 17.1 al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 359 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. property value i.b.p (oc) 195 e.b.p (oc) 322 2.2 catalyst preparation mos2 was synthesized by a hydrothermal method using 1l stainless steel autoclave reactor (model: kurla (w), mumbai-400070, india). a schematic of the synthesis setup was seen in figure (1). figure (2) represents a block diagram of the synthesis procedure. 0.0378 moles moo3 and 0.1415 moles na2s.9h2o were dissolved in 0.3l distilled water by stirring for 10 minutes to ensure homogeneous solution formation and then slowly 0.0425 ml of 4 m hcl solution was added. a black solution was formed by adding hcl. the solution was putted into an autoclave reactor and reacted at 280-320 ˚c and 25-35 bars at 500 rpm for 120 minutes. thereafter, the reactor was instantly cooled down by using a chiller. black solid particles resulted from the synthesis was filtered and washed several times with deionized water and ethanol, and dried under nitrogen of atmosphere pressure at 160 °c for 240 minutes (zhang et al., 2015). 1n2 gas; 2gas pressure regulator; 3-sampling valve; 4-batch reactor with heat and mixing component; 5temperature and speed control system; 6-chiller; 7motor stirrer. figure (1): schematic of the synthesis setup. al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 360 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (2): block diagram for the production of mos2 catalyst. 2.3 identification of catalyst xrd analysis of mos2 was conducted using a diffraction unit [shimadzu-6000, japan]. x-ray diffractometer (xrd) with a 2ɵ range from 10o to 80o with scan rate 2 (deg/min) and cu-kα (λ = 1.541 å) as radiation source was applied. the analysis was carried out at the central service laboratory in the university of baghdad. morphology analysis of mos2 was performed using sem instrument [vega 3 lm, germany] at the university of technology. the specific surface area and pore volume of mos2 catalyst were determined utilizing brunauer emmett and teller (bet) method using analyzer (q surf 1600, usa).the instrument is available in the petroleum research and development centre in baghdad. 2.4 experimental setup for kinetic study and catalyst activity the reactor was charged with mos2 (0.5 gm), and 100 ml of gas oil (go). seal test was conducted on reactor by purging several times with hydrogen and then raised pressure to 35 atm with stirring 600 rpm which ensure of getting rid of mass transfer resistance. operating temperature was varied at 300360oc. h2 was fed continuously during the test in order to shun the decreasing of h2 pressure due to the reaction. as the reaction continued samples were drawn periodically. the influence of sampling on mixture volume was neglected because of the small sample amounts (≤ 1.0 ml per sample). sulfur analyzer (xos, sindie otg, usa) was used to measure sulfur concentration in drawn samples. the sulfur removal is calculated from equation (1). where cf and c(t) are initial and instantaneous sulfur concentrations respectively. (1) al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 361 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3. results and discussion 3.1 effect of operating parameters on catalyst characteristics 3.1.1 influence of temperature figures (3a) and (3b) demonstrate xrd images for the effect of temperature (300 and 320 oc), at constant pressure (35 bars), on crystalline structure and phase purity of mos2 nanostructures. as could be seen, all peaks presented in the two images have nearly the same locations on the 2 𝜭-axis. however, at 300 oc, a small peak appears at 56.6◦, seen as left shift of 110 lattice facets. the spectra indicate a more amorphouslike mos2 (fig. 3a-mos2) structure at low temperature. when the synthesis temp increases to 320◦c, a crystalline structure (denoted as fig. 3b-mos2 hereafter) starts to develop, manifested by the characteristic peaks for 002, 100, 103, and 110 facets (fig. 3a-b).the broad peaks, on the other hand, also reveal poor crystallite structure. the peak intensities were enhanced with increased synthesis temperature. as the temperature increased from 300 to 320 oc, the corresponding 2θ reflections became sharper and could be clearly observed. moreover, sizes of peaks in fig. 3a are smaller than in fig. 3b, indicating that mo and s powders could not completely react at the lower temperature. this confirmed the predominant effect of temperature on the yield of mos2. as can be observed in figure 3b, the xrd peaks can be recorded to those of the perspicuous hexagonal phase of mos2 with lattice coefficients a = 3.161 å, c = 12.84 å, which are agree well with the amounts of standard card (jcpds no. 37-1492). no featured peaks were revealed from other impurities, pointing out that the sample has high purity. the application of xrd showed that the crystal structure of the particles was hexagonal. additionally, the comparison of the obtained peaks in figures 3a and 3b indicated that the mos2 nanoparticles average particle size was calculated, according to scherer’s equation (eq. 2), approximately as 32 and 21nm at temperatures of 300 and 320 oc respectively. where d is the mean crystalline size (nm), is the wavelength of cu ka (0.154 nm), is the full width at half maximum intensity (fwhm) in radian and is the bragg angle.however, choi et al. (2018) reported that the rising of synthesis temperature increases the reaction rate of moo3 to mos2 it decreases the number of active sites available for the reaction. these findings of choi et al. confirmed that there is an optimum temperature for the synthesis of the catalyst. (2) al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 362 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (3): xrd images (a) at 300 ∘c & 35 bar and (b) at 320 ∘c & 35 bar. 3.1.2 influence of pressure figure (4a) and (4b) demonstrates xrd images for the effect of pressure (25 and 35 bar) at constant temperature (280 oc). the main perceptible xrd peaks can be easily recorded to the hexagonal phase of mos2 compatible with the standard powder xrd folder of mos2 (jcpds 37-1492), and there is peak from impurity due to incomplete moo3 conversion. moreover, the strength of the xrd peaks of mos2 varied significantly under different imposed pressures. with further increasing of the reaction pressure to 35 bars, xrd pattern (figure. 4b) shows that the intensities of xrd peaks of mos2 increase. as seen in figure 4, the higher and acute peaks depict that the sample was quite crystallized. the higher the imposed pressure is, the better the crystallized products will be. sulfur concentration on mo films is related to the dynamic pressure within the reactor. by increasing the pressure, the concentration of sulfur on mo surface increases, therefore, a higher nucleation density of mos2 was expected on the mo film. these nucleation sites cannot proceed further when low pressure applied because of low sulfur concentration at mo surface. the high and sharp diffraction peak of (fig. 4b) of the as-prepared mos2 samples indicates the formation of well-stacked layered structure of mos2 during the hydrothermal process. our results agree well with findings of (wang et al., 2017). in te n si ty 2θ al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 363 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (4): xrd images (a) at 280 ∘c & 25 bar and (b) at 280 ∘c & 35 bar. 3.1.3 edx, sem, and bet measurements edx, sem, and bet measurements were conducted after the best synthesizedtemperature and pressure determined (as seen in fig. 3b). figure (5a) and (5b) shows images of edx, and sem for synthesized mos2. it is shown in fig. (5a) that only the special feature of xrd peaks of hexagonal 2h-mos2 and no oxides mo are revealed, which points out that the prepared mos2 catalyst is indeed a complete sulfide catalyst. image (5a) shows that the composition of mos2 catalyst is 14.39 wt% mo and 85.61 wt % s indicating a typical composition of a pure mos2 catalyst. figure (5b) for sem images at 41.5 and 104 μm snapshots for the surface morphology of mos2 catalyst confirms the surface composed thoroughly of regular equal-sized particles. table (2) list values of bet surface area and pore volume of mos2 catalyst synthesized at different pressure and temperature. table (2) depicted that the surface area and average pore size increase as the pressure and temperature are increase within the studied range in the present work. catalyst surface area (sg) is related to both pore volume (vg) and average pore radius (a) by eq.(3), cited in smith (1981). it is obvious from eq. (2) that as sg increased and a is decreased, vg increases correspondingly to satisfy the relation of eq.(2). wu et al. (2014) studied the effect of synthesis temperature on characteristics of unsupported mos2 and comos2 catalysts for hydrodesulfurization of dibenzothiophene. the authors found that as synthesis temperature increased catalyst surface area increased while average pore diameter showed a different trend. wang et al. (2017) synthesized mos2 nanocomposites by high pressure hydrothermal method. wang et al. revealed that when the initial pressure increased from 2.5 to 3.5 mpa, the corresponding surface area increased and all the morphologies of products are nanoflowers with a width of 10~20 nm. the published data have confirmed our experimental observations (see table 2) for the effect of synthesis temperature and pressure on catalyst surface area and pore volume. in te n si ty 2θ al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 364 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (5a): edx of mos2 catalyst synthesized at t= 320 oc, and p= 35 bar. (i) al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 365 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (5b): sem images (i) left, at 41.5 μm view; (ii) right, at104 μm view table (2): bet measurements of mos2 catalyst synthesized at different synthesis conditions property 300 oc & 25 bar 320 oc & 25 bar 320 oc & 35 bar surface area, m2/g 204.3 214.35 231.48 pore volume, cm3/g 0.597 0.687 0.758 (ii) al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 366 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3. 2 kinetic study and catalyst activity the kinetic mechanism of hds reaction on catalyst has a predominant effect on the activity of catalyst. (rabarihoela et al., 2009 and chacón et al., 2012) proposed a two site adsorption mechanism for s species and h2 over the catalyst surface, where, k is the reaction rate constant, ks, kh, and kh2s are the adsorption constant of ch4s, h2, and h2s. cs, ch, and ch2s are the concentrations of sulfur compound, h2, and h2s. since h2 was in excess, khch and eqn. (4) becomes if the sorption of h2s could be taken into account as greater than c4h4s over the solid surface, then (1+ kh2sch2s) kscs, eqn. (5) becomes the rate law of the hds reaction is where, khds is the specific rate constant containing the adsorption influence of h2s. cs could be written as, where, cso and are the incipient weight content and conversion of sulfur, respectively eqn. (9) is treated by integration and rearranged to obtain: is calculated by a graph of vs. t , where is represented by the slop. if the experimental result generated a straight line, this indicated a pseudo-first order trend. the required energy (ea) to break down the r–s bond over the selected catalysts can be calculated from arrehenius equation by plotting the left-hand side of eqn. (11) against [1/t]. ln khds = (-ea /r).(1/t) + ln a the applicability of pseudo first order kinetics was checked at three levels of temperature 300, 340, and 360 ∘c, while pressure was kept constant at 35 bar. as shown in fig. (6), the plot of [–ln (1-xs)] versus [time] is linear, thus confirming that the pseudo first order kinetics could be used to represent the data. on the other hand, it can be clearly observed in fig. (6) that an increase in the contact time caused a linear (4) (5) (6) (7) (8) (9) (10) (11) al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 367 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. increase in value of the term (–ln (1 – xs) value) whose slope represents the specific reaction rate over mos2 catalyst at the studied reaction temperatures. it can also be seen in figure (6) and table 3, that the reaction rate constant raises as the catalyst activity increases. as a consequence, a higher conversion at various temperatures was found. figure (6): plot of [–ln (1-xs)] versus [time] at different temperatures. table (3): values of khds at different operating conditions temperature (∘c) khds (h-1) 300 1.288 340 2.067 360 2.199 al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 368 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. the activation energies of hds reactions over mos2 catalyst were calculated from the arrhenius expression in equ. (11). slope of the line in figure (7) represents the value of activation energy for hds reaction over unsupported mos2 catalyst in terms of (– ea/r). according to figure (7), the activation energy (ea) = 26.36 kj/mol. figure (7): plot between (ln khds ) versus (1/t). figure (8) illustrates the effects of temperature on sulfur removal from gas oil while other operating parameters were kept constant at (p=35 bar, wmos2 = 0.5 gm). it can be observed that a positive relationship was established between sulfur removal and operating temperature. the sulfur removal, after 60 min of hds reaction of gas oil, is 96.2, 95.8, and 88.0% at temperatures 360, 340, and 300 oc respectively. this may be because of the equilibrium limitations at higher reaction temperatures for reversible hds reactions. moreover, figure(8) illustrates a comparison between unsupported mos2 catalyst and supported como/al2o3 composed of 15.5 wt% mo and 5.5 wt% co, catalyst for hds of iraqi gas oil produced by aldaura refinery, baghdad (abid et al., 2018). as can be observed, mos2 catalyst offers 7.3% increasing in sulfur removal over como/al2o3 although the later catalyst has a higher weight percentage of mo with 5.5 wt% of the promoter (i.e., co). al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 369 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. figure (8): variation of sulfur removal against temperature after 60 min of hds reaction of gas oil for mos2 catalyst (present work) and como/al2o3 catalyst (abid et al., 2018). 4. conclusions unsupported mos2 catalysts were synthesized for the (hds) of real feed gas oil using different temperatures and pressures in the hydrothermal method by utilizing molybdenum trioxide and sodium sulfide. the characterization of the catalyst was identified by xrd, sem, and bet techniques. it was found that the bet surface and the pore volume were positively affected by pressure and temperature, which could improve the activity of mos2. kinetics analysis of the studied system depicted that the hds reaction of gas oil over mos2 unsupported catalyst behaved as a pseudo-first order with the rate constant at 300,340, and 360 oc equals to 1.288,1.96, and 2.14 hr-1, respectively and has activation energy = 26.36 kj/mol. experimental results revealed that the hds activity of the unsupported mos2 catalyst was predominant over supported como/al2o3 catalyst under the same operating conditions. acknowledgement authors thank the department of chemical engineering, the university of technology for supporting this work. thanks to the petroleum research and development center, iraqi ministry of oil for their valuable assistance. al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 370 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. references 1.abid m. f., ahmed s. m.,abdullah m.k.., ali s. m., experimental study on catalyst deactivation by nitrogen compounds in a hydroprocessing reactor”, the arabian journal for science and engineering (2018) 43:2133–2143 2.alvarez l., berhault g., alonso-nunez g. unsupported nimo sulfide catalysts obtained from nickel/ammonium and nickel/tetraalkylammonium thiomolybdates: synthesis and application in the hydrodesulfurization of dibenzothiophene. catalysis letters. 2008 sep 1; 125(1-2):35. 3.chang l., yang h., li j., fu w., du y., du k., yu q., xu j., li m. simple synthesis and characteristics of mo/mos2 inorganic fullerene-like and actinomorphic nanospheres with core–shell structure. nanotechnology. 2006 jul 6; 17(15):3827. 4.chacón r., canale a., bouza a., sánchez y. modeling of a three-phase reactorfor bitumen-derived gas oil hydrotreating. brazilian journal of chemical engineering. 2012; 9(1): 135-46. 5.choi j.m., kim s.h., lee s.j., kim s.s. effects of pressure and temperature in hydrothermal preparation of mos 2 catalyst for methanation reaction. catalysis letters. 2018:1-2. 6.dhas n.a., suslick k.s. sonochemical preparation of hollow nanospheres and hollow nanocrystals. journal of the american chemical society. 2005 mar 2; 127(8):2368-9. 7.duphil d., bastide s., lévy-clément c. chemical synthesis of molybdenum disulfide nanoparticles in an organic solution. journal of materials chemistry. 2002; 12(8):2430-2. 8.eijsbouts s., mayo s.w., fujita k. unsupported transition metal sulfide catalysts: from fundamentals to industrial application. applied catalysis a: general. 2007 apr 16; 322:58-66. 9.gaojun a.n., changbo l.u., chunhua x., production of clean diesel fuel by the efficient hydrotreating technology, the second china energy scientist forum, beijing (2010). 10.girgis m.j., gates b.c. reactivities, reaction networks, and kinetics in high-pressure catalytic hydroprocessing. industrial & engineering chemistry research. 1991 sep; 30(9):2021-58. 11.he z., que w. molybdenum disulfide nanomaterials: structures, properties, synthesis and recent progress on hydrogen evolution reaction. applied materials today. 2016 jun 1; 3:23-56. 12.hensen e.j., kooyman p.v., van der meer y., van der kraan a.m., de beer v.h., van veen j.a., van santen r.a. the relation between morphology and hydrotreating activity for supported mos2 particles. journal of catalysis. 2001 apr 25; 199(2):224-35. 13.rabarihoela v., diehl f., brunet s. deep hds of diesel fuel: inhibitingeffect of nitrogen compounds on the transformation of the refractory 4,6-dimethyldibenzothiophene over a nimop/al2o3 catalyst, catal lett. 2009; 129: 50–60. 14.schweiger h., raybaud p., kresse g., toulhoat h. shape and edge sites modifications of mos2 catalytic nanoparticles induced by working conditions: a theoretical study. journal of catalysis. 2002 apr 1; 207(1):76-87. 15.smith j.m. chemical engineering kinetics, third edition, mcgraw-hill international editions, singapore (1981). al-qadisiyah journal for engineering sciences vol. 11 no. 3 issn: 1998-4456 page 371 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 16.speight j.g., ozum b., editors. petroleum refining processes. crc press; 2001 oct 31. 17.théodet m., 2010. new generation of" bulk" catalyst precursors for hydrodesulfurization synthesized in supercritical fluids (doctoral dissertation, université sciences et technologies-bordeaux i). 18.wang y., lia x., wang c. synthesis and characterization of mos2 nanocomposites by a high pressure hydrothermal method. journal of non-oxide glasses vol. 2017 apr 1; 9(2):47-54. 19.wu z., zhu w., wang d., whiffen v.m.l., smith k. j. effect of annealing temperature on co–mos2 nanosheets for hydrodesulfurization of dibenzothiophene, catal lett (2014) 144:261–267. 20.zhang h., lin h., zheng y., hu y., maclennan a. understanding of the effect of synthesis temperature on the crystallization and activity of nano-mos2 catalyst. applied catalysis b: environmental. 2015 apr 1; 165: 537-46. template for academica science journal al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 426 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. numerical investigation of rougness effects on hyderdynmic and thermal performance of counter flow microchannel heat exchanger ahmed a. ali mechanical engineering department, college of engineering, thi-qar university, iraq e mail: eng.ahmedameen91@gmail.com mushtaq i. hasan mechanical engineering department, college of engineering, thi-qar university, iraq e mail: mushtaq76h@gmail.com ghassan adnan mechanical engineering department, college of engineering, thi-qar university, iraq e mail: ghassanadnan37@gmail.com abstract: in this paper the effect of surface roughness on the performance of counter flow microchannel heat exchanger has been numerically investigated. the studied microchannel heat exchanger is a square shape and made of aluminum as substrate material with different values of hydraulic diameters (20, 50, 110, 150 ) μm. the working fluid used is water at constant properties. roughnessviscosity model has been used to study the roughness effect with 0.14 ratio of roughness to hydraulic diameter. the results obtained indicate that pressure drop of (cfmchx) increased with increasing surface roughness and decrease hydraulic diameter also the results showed that there is a slight increasing in thermal performance with increasing the surface roughness. keywords: surface roughness, microchannel heat exchanger, laminar flow, numerical investigation, thermal performance mailto:eng.ahmedameen91@gmail.com mailto:mushtaq76h@gmail.com mailto:ghassanadnan37@gmail.com al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 427 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. nomenclature: symbol description si unit cp specific heat j\kg.k dh hydraulic diameter m f friction factor h height m k height of the roughness element m . m mass flow rate kg/s p.p pumping poewer watt t temperture k uk velocity at the top of roughness m/s uavg average velocity m/s u fluid x-component velocity m/sec re reynold number rek local reynold number rvm roughness viscosity model w width m δp pressure drop across heat exchanger pa ρ density kg/m3 μr roughness viscosity m2/s μp apparent viscosity m2/s  * performance factor ɛ heat exchanger effectiveness al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 428 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. introduction in recent years, advanced micro fabricated technology as heat exchanger received large interest and increase the using in many applications due to heat transfer dissipation over small size this invites to use it in biomedical process, microelectronics ,metrology and aerospace application so the study of the overall performance of microchannel heat exchanger with different parameters is very important[1]. decreasing the hydraulic diameter has a considerable effect on all parameters also the roughness effect play important role on hydraulic and thermal performance of microchannel heat exchanger (mchx). there are many researches in literature studied many parameters affecting the performance of microchannel heat exchanger including roughness effect. below a review of most related papers. mala and li (1999) [2] presented experimental work to investigate the performance on microchannel with diameter ranging from (50 254) μm by using roughness viscosity model. [rvm] has been used to study the roughness effect on microchannel. [rvm ] treat the roughness effect as apparent viscosity in momentum equation. the apparent viscosity μp is the sum of viscosity of fluid μf and roughness viscosity μr. the authors solved the momentum equation analytically for cylinder with adding the roughness viscosity. [rvm] appears large agreement with experimental data in varying hydraulic diameter. their results showed that, the early transition from laminar to turbulent which cause it the effect of surface roughness. weilin et al (2000)[3] studied experimentally micro aching techniques fabricated the trapezoidal channel with relative roughness value (2.4 % 3.5%) due to silicon surface finish and hydraulic diameter ranging ( 51-169 ) μm .they concluded that the friction factor and pressure drop in microchannel higher than those given by conventional theory due to the surface roughness effect. qu et al (2000) [4] studied the effect of surface roughness on heat transfer characteristics of water as working fluid flow through trapezoidal silicon microchannel with the hydraulic diameter ranging from ( 62-169) μm. they found that, the velocity near the wall surface is decreased due to the effect of surface roughness. they proposed a roughness – viscosity model [rvm] to interpret their experimental data based on this model. hassan. et al (2009) [5] evaluated the effect of channel geometry fluid flow and heat transfer behavers of counter flow microchannel heat exchanger by using numerical simulation. the effects of different channel shapes on performances of (cfmchx) are studied for five shapes (square, rectangular, triangular, trapezoidal and circle). the results showed that, for the same volume of heat exchanger, increase number of channel leads to increase both pressure drop and effectiveness also they developed a new correlations to predicted the value of heat exchanger effectiveness and performance index as function of relative size channel with re, overall volume of heat exchanger and thermal conductivity ratio.dang.et al (2010) [6]presented experimental testes and numerical simulation to study the fluid flow and heat transfer characteristics of counter microchannel heat exchanger for rectangular shaped has hydraulic diameter of 375 μm and heat flux applied was 17.38 w/cm2 was achieved for water from cold side having inlet temperature of 21.5 and mass flow rate 0.2906 g/sec and for hot side having inlet temperature 70 and mass flow rate 0.2503 g/sec. from result obtained that, al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 429 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. pressure drop increase as water temperature rises where pressure drop increases from 880 to 4400 pa. also obtained a good agreement between numerical and experimental results. byongjoo kim (2016) [7] investigated microchannel to study the flow resistance and thermal behavior in ten rectangular microchannel with aspect ratio ranging from (0.25 -3.8). he used fc 770 and deionized water as working fluids. the relative roughness measured by digital device was 3.7 mm. he observed through experimental demonstrate large deviation in poiseuille number(fre) because the surface roughness as the channel size decrease. also the result showed that ,the existing roughness in microchannel cause early transition to turbulent flow. in this paper the effect of the surface roughness on the performance of counter flow microchannel heat exchanger will be numerically studied by using roughness – viscosity model on thermohydraulic characteristics .in addition to relation between channel and roughness effect. 1. mathmatical model: the schematic drawing in fig (1) shows a physical model of problem. which represents counter flow microchannel heat exchanger (cfmchx) consists of square channels with hot and cold fluids where the working fluid ( water) inters in upper channel as cold fluid while in the lower as hot fluid. there are many diffcults with soling complet heat excanger, where need much time and super computers there fore one unit is used in this study. the selected unit consists of hot and cold channel and separating wall between them. for each channel the length (l) equal to 500 μm, width of the channel( w) , (ts) is the thickness of separating wall between cold and hot fluid of (5 μm) and the aspect ratio equals to one as seen in fig.2 the governing equations used in this paper based on the following physical and geometry assumptions :  the flow is laminar and steady.  the value of knudsen number is smaller thane 0.001 for continuance fluid (no slip).  water used in this paper is incompressible, constant properties and newtonian.  there is no heat transfer to\from the ambient  the energy dissipation is negligible.  the pressure drop in axial direction only.  three dimensional flow and heat transfer . the governing equations and boundary conditions in cartesian are write below [8] [9][10] continuity equation: al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 430 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. (1) momentum equation: (2) energy equation: (3) mala and li [2] modified roughness viscosity model where surface roughness in laminar flow considered in terms roughness – viscosity function . the apparent viscosity in momentum equations become viscosity of fluid sum roughness viscosity as equ.9 . the ratio of roughness to hydraulic diameter is 0.14 and k is average height of surface roughness. ) (4 2)) k r -exp(-(1 k r a )(4) =  r (5) k r=k ) r u   = (ku (6) /v 2k r =r) r u   = (kre (7) = r =r) r u   ( a=0.1306 ( k r )0.3693 exp {re (6 10-5 k r 0.0029) (8) the apparent viscosity of fluid is µp=µ+ µr (9) 0v tktvc p 2 )(  ).().( vpvv   al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 431 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. uci tci hc c ts h hh l h thi w uhi y fig.1.model of cfmchx[10] fig (2) unit cell of cfmchx[10] al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 432 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 2.boundery conditions: the boundary conditions used to complete the model are: for lower channel (hot fluid) location b.c comments at z =0 u=uhi , vh= wh=0 , th=thi hot fluid in flow at z= l = vh = wh =0 , =0 hot fluid out flow (fully developed flow , end of channel ) at x =0 uh = vh = wh =0 , noslip, adiabatic wall at x = w uh = vh = wh =0 , noslip, adiabatic wall at y = 0 uh = vh = wh =0 , noslip, adiabatic wall at y =hh uh = vh = wh =0 ,-kh = ks , fluid – solid interface ts =th (no –slip conjgat heat transfer) for upper channel ( cold fluid) (hh + t  y  hh + t +hc ) location b.c comments at x = 0 = vc =wc =0 , = 0 cold fluid outlet (fully developed fully developed flow end of channel at x= w uc= uci , vc =wc = 0 , tc= tci cold fluid inflow at z = 0 uc= vc =wc =0 , = 0 no –slip adiabatic wall al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 433 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. at z =l uc= vc =wc =0 , = 0 no –slip adiabatic wall at y = hh + t uc= vc =wc =0 , kc = ks , tc =ts fluid –solid interface ( no slip, conjugate heat transfer) at y = hh + t +hc uc= vc =wc =0 , (no slip adiabatic wall ) for solid wall separating two channels (hh  y  hh + t) location b.c comments at x = 0 and x=w = 0 adiabatic wall at z=0 =0 adiabatic wall at z=l =0 adiabatic wall at y= hh ,-kh = ks , ts =th fluid –solid interface at y = hh + t kc = ks , tc = ts fluid –solid interface by cfd code the above equations with their boundary conditions have been solved, and values of velocity, pressure, effectiveness, pumping power, friction factor and overall performance are calculated the inlet velocity is calculated based on reynolds number. re = (10) where dh is the hydraulic diameter. from darcy equation can be friction factor [11] al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 434 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. f = uavg p 2  l d  2 (11) and the total pressure drop in heat exchanger unit is the summation of the pressure drop in the hot fluid channel and the cold fluid channel. δpu = δpch.h + δpch.c = (ph.i – ph.o ) + (pc.i –pc.o ) (12) heat exchanger effectiveness is the ratio of the actual heat transfer to the maximum possible heat that can be transferred[10]: ) = ) = (13) for any heat exchanger the effectiveness is a function of ntu and the heat capacity ratio. ε = f (ntu, cr) where ntu is the number of transfer units ntu = and cr is the heat capacity ratio cr = (14) volumetric flow rate multiplying total drop pressure. [12] p.p = . v p (15) to calculate the performance factor of heat exchanger the performance factor has been used to correlate the hydrodynamic and thermal performance as define below  * = pp q . (16) al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 435 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 3.numerical solution: the above system of governing equations and boundary conditions are numerically solved using finite volume method. the flow is developing; the 3d continuity and 3d naiver stock equations are solved numerical by fluent ansys . a mesh has been chosen in accepted size and a mesh refinement has been made to find out the appropriate mesh size that gives highly accurate solution as indicate in table (3).table 3 shows that the solution becomes independent of grid size and from third mesh further increase in the grids will not have a significant effect on the solution and results of such arrangement are acceptable. therefore the fourth mesh size is used for all calculations. table 1 grid independent study mesh size outlet temperature (k) mesh1 (number of elements=1320743) 308 mesh2 (number of elements=1528356) 308.93 mesh3 (number of elements=1963380) 308.95 mesh4 (number of elements=2575633) 308.96 the convergence criteria used to control the numerical solution for both momentum and energy equations are 10-6. the properties of material are list in table (4) below [13 ] table (2) properties of selected material property material water aluminum thermal conductivity (k) (w/m2.k) 0.643 273 specific heat cp (j / kg .k) 4200 871 density(kg / m3 ) 1000 2791 viscosity (m2/s) 0.001 ـــــ al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 436 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 4. results the model was solved with pure water as a working fluid with constant properties selected according to the mean temperature across heat exchanger. two cases have been solved for each size with considering surface roughness and with neglecting it to explore the effect of roughness on the performance of (cfmchx) to check the validity of the built numerical model, verification was made by solving the experimental model presented in [7] and the results were compared. the experimental model presented in [7] is a rectangular microchannel with aspect ratio 1.92 μm. the width (265  m), height (510  m), length (76 mm) and hydraulic diameter (348.8  m). the author used fc770 and deionized water used as working fluid. the surface roughness of aluminum measured was 3.7  m due to surface finish of machining. fig. 3 shows the comparison between results of present numerical model and the experimental data of [7] for variation of friction factor with reynolds number. from this figure it can be seen that, the agreement between numerical and experimental results is acceptable with the average error of 5% which may be due to difference in material properties and some assumptions in this model. to check the behaver of thermal side, another validation has been made with reference [14] as shown in fig. 4 shows the validation between results of present model with data in albakhit and fakeri 2006[14]. the figure explains that, the variation of dimensionless axial distance x* = with dimensionless mean temperature tm = for the cold and hot fluids flows in rectangular microchannel heat exchanger at reynold number is 100 and =100. it can be noted in this figure that there is a good agreement between the results of present model and that in [14] where the maximum error was 1% due to the difference in some assumptions between them. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 437 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig (5) shows the velocity variation on planes drawing a long the channels of (cfmchx). the channels have hydraulic diameter (dh = 50  m) and re =100. it can observed in this figure that the velocity of flow in entering of cold and hot channels is maximum value and decreasing flow velocity with toward flow. fig (3) variation of friction factor with re as comparison between results of present model and that of [7] fig(4) variation of mean temperature with dimensionless distance as comparison between results of present model and that of [14] al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 438 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig.6 explains the distribution of pressure drop contour in (y-z) plane at same value of re and hydraulic diameter of previous figure. pressure drop in hot channel is larger than cold channel due to affect temperature which leads to increase it. also it can be seen that the surface roughness increased the pressure drop due the restriction between molecules of fluid. fig (5) planes of contour represent the velocity(m/sec) in cold and hot cells of cfmchx at dh = 50 μm and re=100 fig(6) pressure(pa) distribution contour along cold and hot channel of cfmchx has dh = 50 μm and re = 100 al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 439 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig.7 shows variation of pressure drop at many plane distributions a long hot and cold channel of (cfmchx) with hydraulic diameter of ( dh =50  m) and re =100. it can be noted that in fig.7 the pressure drop increased with increasing velocity of flow which due to increase mass flow rate. fig.8 shows contour of variation temperature distribution a long (cfmchx). the hot fluid entering at th =100 c and cold fluid tc =50 c. as seen in this figure the temperature difference in cold channel increase toward fluid while in hot channel decreased due to heat transfer. fig(7) contour show many planes of pressure (pa) along cold and hot cell of cfmchx at dh =50 μm and re =100 fig (8) temperature(k) distribution contour along hot and cold cells of cfmchx as re =100 and dh = 50 μm al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 440 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig.9 shows the variation of temperature on contours on many planes distributed along the channels of (cfmchx). as can be seen from this figure that the temperature increased with increase residence time and decreased the velocity of flow. fig.10 shows the variation of effectiveness with reynolds number at different values of hydraulic diameter (20,50,110,150) μm with considering roughness effect and neglecting it. it can be seen from this figure that the effectiveness decreased with increasing reynold number for all diameters due to decreasing temperature difference with increase the velocity of flow. for all selected range of hydraulic diameters it can been noted in fig.10 decreasing the effectiveness with increasing values of hydraulic diameter because the area of heat transfer increasing with size. also it can be observed that, the effect of surface roughness is small on the effectiveness which is due to independent of temperature on roughness as a result of constant properties assumption. fig(9) many planes of temperature(k) explaining as contour at dh = 50 μm and re =100 fig (10) show variation of effectiveness ( ɛ ) with re number with and without considering roughness effect. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 441 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig.11 shows the variation of changing in friction factor ( the difference between friction factor with roughness effect and friction factor without it ) with reynolds number for selected range of hydraulic diameters (20,50,110,150) μm. from this figure it can be noted that, the change in friction factor decreased with increasing reynolds number due to increase the velocity of flow according to darcy equatio. fig. 12 explains the relation between pressure drop difference and reynolds number at different hydraulic diameters. the pressure drop difference in this figure represents the difference between value of pressure drop with considering surface roughness and with neglecting it. as can be observed in the fig.12 the pressure drop difference is maximum at small diameters due to decreasing the area of flow. this figure shows that, pressure drop difference is increased with increasing reynolds number due to increasing the velocity of flow since the losses is maximized at higher velocity. the surface roughness has very important roll on increasing the value of pressure drop because of the resistance which is show against the fluid flow. fig (11) explain variation of friction factor with re for different values of hydraulic diameter al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 442 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig.13 shows the variation of decrement of pumping power (the difference between the value of pumping power with roughness effect and its value with neglecting it) with reynolds number through many values of hydraulic diameter. as can be seen in fig.13 the difference of pumping power increased with increasing the reynolds number because of increasing the pressure drop and velocity of flow. also it can be seen in this figure that, the pumping power is increased with decreasing hydraulic diameter due to high pressure generated in small diameter. the roughness effects work to increase pumping power value and hydraulic performance generally because of the resistance which causes it. fig(12) variation pressure drop difference with re for different value of hydraulic diameter fig (13) variation of pumping power difference with re for different hydraulic diameter al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 443 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. fig.14 represent cooperation between performance factor( it is ratio of heat transfer rate to pumping power) and reynolds number for two cases , one depending the surface roughness and another neglecting it. the fig (14) divided to (a) and (b) to explain clear variation with different values of hydraulic diameters. the fig (14a) plotted for diameters range (20,50 ) μm while (14 b) plotted for diameter values (110 , 150 ) μm. from these figures it can be seen that, the performance factor decreased with increasing reynolds for all values of hydraulic diameter due to the increasing of pumping power very high comparison with increasing in convective heat transfer. the roughness effect becomes very clear on overall performance with larger hydraulic diameter. also these figures reveal that, the effect of roughness increased at lower values of re. fig(14-a) variation performance factor with re for two cases with and without considering roughness effect for hydraulic diameter (20,50) μm fig(14-b) variation performance factor with re for two cases with and without considering roughness effect for hydraulic diameter(110, 150) μm al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 444 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. concluations in this paper numerical investigation is made to study the effect of roughness on the performance of cfmchx with different sizes and used water at constant properties as working fluid. from the results it can be conclude that: 1the surface roughness has considerable effect on hydraulic performance and its effect is increased when hydraulic diameter and velocity of flow is small. 2surface roughness enhances the thermal performance slightly. 3 the roughness effect is decreased with increasing reynold number and hydraulic diameter. 4the surface roughness causes an extra increasing in pressure drop and pumping power. 5in general the surface roughness leads to decrease the overall performance of cfmchx. references 1. hasan, m. i. (2011). influence of wall axial heat conduction on the forced convection heat transfer in rectangular channels. basrah journal for engineering science, 1, 31-43. 2. mala, g. m., & li, d. (1999). flow characteristics of water in microtubes. international journal of heat and fluid flow, 20(2), 142-148. 3. weilin, q., mala, g. m., & dongqing, l. (2000). pressure-driven water flows in trapezoidal silicon microchannels. international journal of heat and mass transfer, 43(3), 353-364. 4. qu, w., mala, g. m., & li, d. (2000). heat transfer for water flow in trapezoidal silicon microchannels. international journal of heat and mass transfer, 43(21), 3925-3936. 5. hasan, m. i., rageb, a. a., yaghoubi, m., & homayoni, h. (2009). influence of channel geometry on the performance of a counter flow microchannel heat exchanger. international journal of thermal sciences, 48(8), 1607-1618. 6. dang, t., teng, j. t., & chu, j. c. (2010). a study on the simulation and experiment of a microchannel counter-flow heat exchanger. applied thermal engineering, 30(14-15), 2163-2172. 7. kim, b. (2016). an experimental study on fully developed laminar flow and heat transfer in rectangular microchannels. international journal of heat and fluid flow, 62, 224-232. 8. hasan, m. i. (2011). numerical investigation of counter flow microchannel heat exchanger with mepcm suspension. applied thermal engineering, 31(6-7), 1068-1075. 9. peiyi, w., & little, w. a. (1983). measurement of friction factors for the flow of gases in very fine channels used for microminiature joule-thomson refrigerators. cryogenics, 23(5), 273-277. al-qadisiyah journal for engineering sciences vol. 11, no. 4 issn: 1998-4456 page 445 copyright  2018 al-qadisiyah journal for engineering sciences. all rights reserved. 10. hassan, m. i. numerical investigation of counter flow microchannel heat exchanger with different geometries working fluid , phd thesis, mechanical engineering department, college of engineers, basrah university. 11. qi, s. l., zhang, p., wang, r. z., & xu, l. x. (2007). single-phase pressure drop and heat transfer characteristics of turbulent liquid nitrogen flow in micro-tubes. international journal of heat and mass transfer, 50(9-10), 1993-2001. 12. hasan, m. i., rageb, a. m. a., & yaghoubi, m. (2012). investigation of a counter flow microchannel heat exchanger performance with using nanofluid as a coolant. journal of electronics cooling and thermal control, 2(2), 35-43. 13. shakir, a. m., mohammed, a. k., & hasan, m. i. (2011). numerical investigation of counter flow microchannel heat exchanger with slip flow heat transfer. international journal of thermal sciences, 50(11), 2132-2140. 14. al-bakhit, h., & fakheri, a. (2006). numerical simulation of heat transfer in simultaneously developing flows in parallel rectangular ducts. applied thermal engineering, 26(5-6), 596-603. article al-qadisiyah journal for engineering sciences 13 (2020) 136–143 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: haitham.althairy@qu.edu.iq (haitham. al-thairy) https://doi.org/10.30772/qjes.v13i2.635 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. numerical study on the performance of gfrp rc beams exposed to high temperature nuha hussien a, haitham al-thairy a,* a civil eng. depart. / college of eng./ university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 03 april 2020 received in revised form 22 may 2020 accepted 15 june 2020 keywords: numerical simulation gfrp-rc beams high temperature abaqus heating rate a b s t r a c t this paper presents and validates a numerical model utilizing the nonlinear finite element software abaqus/standard to simulate the performance and failure of glass fibre reinforced polymers reinforced concrete beams under high temperature. a numerical model was firstly developed by selecting the proper geometrical and material modeling parameters with suitable analysis procedures available in abaqus/standard. the developed numerical model was verified by comparing numerical results with the corresponding results of the experimental test extracted from the current study on glass fibre reinforced concrete beams under different elevated temperatures ranges from (20 to 600ºc). validation results have indicated the accuracy of the suggested numerical model. the validated numerical model was implemented to investigate the effect of important parameters on the performance and maximum load of glass fibre reinforced concrete beams under different elevated temperatures that are not considered in the current experimental tests. these parameters include the effect of exposure time or time-temperature history and effect of temperature distribution around the beams © 2020 university of al-qadisiyah. all rights reserved. 1. introduction in building design, fire endurance is one of the major safety requirements. high-temperature effect on structures which are reinforced with frp bars considered one of the more important factors of the design, although this factor has limited attention from the researchers with a limited number of research studies. however, the deterioration in the mechanical properties of frp bars was investigated by several researches. saafi [1] has established a general equation for the degradation in the mechanical properties of frp material under different elevated temperatures. saafi’s equations have been used by a number of researches in the numerical simulation of frp bars[2][3] (see figure 1). abbasi and hogg [4] suggested two methods for predicting the effect of elevated temperature on some properties of glass fibre reinforced concrete beams. the two method was the suggested semi-empirical equation and fe model based on experimental studies conducted by sakashita et al. [5] and lin et al.[6] and al-baghdadi [7]. all beams were reinforced by frp bars at the tension zone and exposed to iso-834 standard fire curve [8].a whole concrete section with homogenous material was considered in finite element model .while the thermal properties of concrete were taken as proposed by abbasi [9] assuming no concrete cracking during the fire test. http://qu.edu.iq/ mailto:haitham.althairy@qu.edu.iq https://doi.org/10.30772/qjes.v13i nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 137 in addition, gfrp rc beam with dimensions of (350mm width × 400mm height) and overall length of 4250 mm and concrete cover of 70mm was designed and simulated by using fe model. comparison of timetemperature curves between the fe model and semi-empirical equation has shown that the fe model underestimates the time-temperature curve while the semi-empirical equation shows good agreements. a) tensile strength b) elastic modulus figure 1 : reduction factor of tensile strength and elastic modulus of various type of frp bars [1] rafi et al. [10] have carried out finite element simulations of rc beams reinforced with cfrp bars under elevated temperature. the concrete was assumed to be isotropic and thermal conductivity and coefficient of thermal expansion was taken according to eurocode 2[11] along with the mechanical properties of concrete at elevated temperature . in addition, the coefficient of thermal expansion of cfrp bars exposed to elevated temperature was assumed constant according to aci440.1r-15 [12] while the mechanical properties of cfrp-bars under elevated temperature were taken from the equations suggested by saafi [1]. however, numerical simulation results have shown large deviation from the experimental results. yu and kodur [3] presented finite element analysis to evaluate the fire performance of concrete beam reinforced by frp and steel bars. according to eurocode 2[11] , asce standard [13] and insulation layout suggested by bisby [14], heat transfer analysis and relevant high-temperature thermal properties of concrete was applied to establish temperature distribution over beam cross-section. both specific heat and thermal conductivity of steel and frp bars were not considered in the analysis due to the neglected effect of these properties on temperature distribution as suggested by lie [15]. gfrp bars were analyzed according to models suggested by previously studies saafi [1], wang and kodur [16], bisby [14], fib bulletin[17] and aci 440.1r-15[12], which proposed a linear stress-strain curve up to failure and a reduction of tensile strength about 25% of gfrp bars under a temperature of 400 °c and 100% under a temperature of 1000 °c . results of the numerical model have shown good agreement with measured data by rafi and nadjai [18] and abbasi & hogg [19]. the main conclusion extracted from this yu and kodur [3] study is that the load capacity of frp-rc beams is less than the load capacity of steel-rc beams under exposed to high temperature. parametric studies were conducted and indicate a notable effect regarding the increasing of concrete cover thickness on the fire capacity of frp-reinforced concrete beams. also, the existing of axial restrain as well as provided frp beams with fire endurances material reflect efficiency in increasing fire capacity. the above-mentioned research studies have reflected the ability of finite element package abaqus in simulating the behavior and ultimate load of frp reinforced concrete beams under exposure to elevated temperature with a very good accuracy .in addition, the stress-strain relationship of normal weight concrete at high temperature proposed by eurocode 2[11]and eurocode 4[20]was successfully used to predict the degradation of the concrete strength under high temperature. however, some of previous numerical models have not considered the degradation of frp mechanical properties exposed to high temperature in there numerical simulations [21]. saafi’ equations was used in the numerical simulations of current numerical study [1] (see figure 1 ). therefore, the main object of the current study is to develop a more accurate numerical model to simulate the performance of gfrp-rc beams exposed to high temperature using the fe software abaqus/standard. 2. numerical model 2.1. material modelling files must be in ms word only and should be formatted for direct printing, using the crc ms word provided. figures and tables should be embedded and not supplied separately. concrete damage plasticity model (cdpm) available within abaqus/standard was utilized in current model to simulate the performance and failure of the concrete material under ambient and elevated temperature. further, the concrete crushing and concrete cracking are assumed as a basic failure criteria for concrete with compression and tension deterioration of material response being taken into consideration .knowing that concrete was modelled as homogenous material. to simulate the plastic behaviour of concrete, the cdpm in nomenclature aci american concrete institute astm american society for testing and materials c3d8r eight-node brick element with reduced integration dc1d2 two-node link heat transfer truss element dc3d8 eight-node liner heat transfer brick element fem finite element modeling frp fiber reinforced polymer gfrp glass fiber reinforced polymer gf fracture energy rc reinforced concrete t3d2 two-node truss element w1 crack opinions at 0.15 of ultimate stress wo crack opinions at ultimate stress 138 nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 abaqus uses several parameters some of which are obtained from experimental tests. in the current model, the required plasticity parameters for the concrete materials are taken as assumed in abaqus and shown in table 1. table 1 : plasticity parameter used in current numerical model parameters assumed value parameters dilation angle ψ 40 dilation angle ψ potential eccentricity ϵ 0.1 potential eccentricity ϵ fb0/fc0 1.16 fb0/fc0 the mathematical model of compressive stress-strain relationship of concrete that suggests by eurocode 4 was adopted in current numerical model for ambient and elevated temperature. figures 2 shows graphical representations of the compressive behaviour of concrete at ambient and elevated temperatures according to eurocode 4 [20]. to account for the reduction in the mechanical properties of concrete due to elevated temperature, compressive strength reduction factors obtained from the experimental tests conducted in current study was used as shown in figure 2. figure 2: stress strain relationships of concrete at high temperature used in the numerical model of current study for concrete under ambient and elevated temperature, tension stiffening was simulated in the numerical model through using fracture energy (gf) (see figure 3) .the value of gf depending on the maximum aggregate size and the required concrete strength as presented in table 3. further, reduction factors of concrete tensile strengths results from the experimental tests was used in current model (see table 2). table 2 : results of tensile strength (ft) concrete cylinders under different elevated temperatures temp. ,˚c 𝐟𝐭𝐞𝐱𝐩.. , mpa 𝐊𝐭 redaction factor 20˚c 2.4 / 300˚c 1.9 20% 400˚c 1.6 33.4% 500˚c 1.4 41% 600˚c 0.9 62.5% figure 3: bilinear softening tension of normal weight concrete used in current model (hillerborg, 1985) table 3 : values of gf for different aggregate sizes and concrete strengths 𝑫𝒎𝒂𝒙., 𝒎𝒎 gf (n/m) c12 c20 c30 c40 c50 c60 c70 c80 8 40 50 65 70 85 95 105 115 16 50 60 75 90 105 115 125 135 32 60 80 95 115 130 145 160 175 the crack initiation and propagation of concrete crack at ambient and elevated temperature was simulate using the tension damage parameters (dt) which determined from equation 1 suggested by abaqius (hibbitt, 2008) as follows: 𝐝𝐭 = 𝟏 − 𝝈𝒕 ƒ𝒄𝒕𝒎 (1) on the other hand, the mathematical model of the stress-strain relationship of the reinforcing steel bars proposed by eurocode 4 [20] was used in modelling the behaviour of the steel bars at ambient and elevated temperature. the modulus of elasticity and yielding stress of steel bars at ambient temperature were taken as 414 mpa and 2×105mpa respectively according to experimental tests. the reduction factors of reinforcing steel bars properties (yield strength, proportional limit and young modulus) at elevated temperature were taken from eurocode 4 . 2.1 material modeling of gfrp bars at ambient and elevated temperature the mechanical properties of gfrp reinforcement bars provided by the manufactured company was used in the numerical model at ambient temperature. however, the reduction factors of the ultimate tensile strength and of elastic modulus of gfrp bars proposed by saafi [1] was used in the numerical model to simulate the degradation of the mechanical characteristics of the gfrp bars at elevated temperature .also ,the reduction factors of the specific heat ,density and thermal conductivity of gfrp bars proposed by kodur et al. [3] was used in the numerical model as indicated in appendix a. knowing that bar element was used to model the reinforcement with a 120 linear line element of type t3d2. nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 139 2.2 geometrical modelling parameters three-dimensional eight-nodes solid with reduced integration hourglass control and reduced integration(c3d8r) available in abaqus/standard was used in current study to model the gfrp-rc beams, bearing plates as well as supporting plates during strucural analysis (see figure 4-a). while, the eight-node solid linear with a temperature degree of freedom( dc3d8) was used in modeling the gfrp-rc beams, bearing plates and supporting plates in the heat transfer analysis. furtheramore three-dimensional two nodes linear displacement truss element (t3d2) and a two nodes heat transfer link element (dc1d2) with a temperature degree of freedom were used in modeling of reinforcing gfrp and steel bars during structural and thermnal analyses respectively .table 4 and figure 4 show elements used in structural analysis and thermal analysis of current study. table 4: element used in current numerical model structural analysis heat transfer analysis part type of element part type of element rc beams c3d8r rc beams dc3d8 bearing plates, and supporting plates c3d8r bearing plates, and supporting plates dc3d8 gfrp and steel bars t3d2 gfrp and steel bars dc1d2 a ) c3d8r and dc3d8 elements b) t3d2 and dc1d2 elements figure 4 : types of elements used in the current numerical model 2.3 assembly of the numerical model the assembly of all parts of gfrp-rc beams used by the present numerical model is shown in figure 5. in order to preclude intensity of the stress at the supports and loading points, steel plates with dimensions of (150×80×10) mm and (150×100×10) mm (length ×width× depth) have been used as supporting and bearing plates respectively. to simulate the same boundary condition used in the experimental tests, displacement /rotation type of the boundary condition option available in abaqus was used. further, the embedded region interaction option was used to simulate the interaction between reinforcement bars and concrete beams. surface to surface tie interaction was used in simulating the relationship between gfrp-rc beams and bearing and supporting plates using the constraint option available in abaqus. figure 5 show the assembled parts of gfrprc beams. ` a) gfrp-rc beam system b) reinforcement system figure 5: schematic representation for the assembled parts of gfrprc beams 2.4 analysis procedure the sequential thermal-structural analysis procedure in abaqus/standards was used in the current study to analyse the gfrprc beams exposed to elevated temperature followed by a static load. this analysis procedure includes two stages as follows: 2.4.1 heat transfer analysis in heat transfer analysis, the temperature was applied on a selected set of concrete external surface as a boundary condition in the heat transfer analysis step using the corresponding time –temperature history obtained from experimental tests (see figure 6).the “amplitude” option available in abaqus/standard was used to specify time–temperature histories from experimental tests. 2.4.2 structural analysis after completing the heat transfer analysis, structural analysis is initiated to obtain the structural performance of gfrprc beams after exposure to elevated temperature. a displacement controlled structural analysis was conducted by applying a lateral displacement as a boundary condition in the center of gfrp-rc beams using boundary condition option in abaqus bearing plate supporting plate rc beams gfrp bars stirrup 140 nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 a ) t=350˚c b) t=500˚c c ) t=600˚c figure 6: time-temperature histories of experimental tested gfrprc beams under different temperatures 3. validation of the numerical model to ensure the reliability of the developed numerical model, experimental tests were carried out in this study on rc beams subjected to elevated temperature followed by concentrated static load at the beam’s midspan .the numerical simulation results obtained from the suggested model will be compared with the experimental tests results. the section below describes the experimental tests used in the validation of current numerical model. 3.1. experimental test four gfrp-rc beams with cross-sectional dimensions of 250mm ×160 mm (width × height) and a total length of 1250 mm were designed according to aci440.1r-15[12](see figure 7). all gfrp-rc beam specimens are made from normal weight concrete with an average compressive strength of 46 mpa .one beam specimens was tested at ambient temperature and the other three beams were firstly exposed to elevated temperatures of 350°c, 500°c and 600°c using electrical furnace then subjected to a monolithically increased load up to failure. the internal dimensions of the furnace are 130×300×290 mm (length ×depth ×height) with maximum temperature of 900 °c was used to heat up the rc beam specimens .the average heating rate of the furnace is about 10°c /min and decrease gradually to the end of the heating process. an external thermocouple was attached to the specimens through a small hole in one long side of the furnace. two thermocouples were used to measure and record the temperatures-time history at the concrete and at the gfrp bars. in addition, figure 8 show set up of electric furnace. figure 7: dimension and rienforement details of rc-beams used in current study (a)electric furnace during thermal test (b) thermally tested rcbeam figure 8 : set up of the electric furnace all gfrp-rc beams were tested using the universal testing machine obtained at the structural laboratory of college of engineering/ the university of al-qadisiyah. deflection at mid span corresponding to each load increment during the structural tests was monitored and recorded using a linear variable displacement transducer (lvdt) with a maximum capacity of 50 mm. 3.2. validation of the numerical model against thermal tests the results obtained from heat transfer analysis were presented in terms of temperature timehistories at the surface of main reinforcement gfrp bars and compared with temperature timehistories of corresponding experimental thermal tests as shown in figure 9 .the comparisons show reasonable agreement between the numerical simulation results and the experimental tests results especially at maximum temperature transferred from concrete to the gfrp bars. this agreement indicates the accuracy of the suggested model in capturing the temperature distribution inside the concrete cross-section. in addition, figure 9 clearly shows that as the distance from concrete surface increased the corresponding temperature is considerably decreases. nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 141 a) under 350 ºc b) under 500 ºc c) under 600 ºc figure 9 : temperaturetime histories at the surface gfrp bars of the tested beam 3.3. validation the numerical model against the structural tests the results of numerical model in terms of ultimate load-lateral displacement relationships of gfrp-rc beams were compared with the corresponding experimental load-displacement relationships .figures (10a-d) illustrate the comparison for gfrp rc beams. good agreement can be seen between the two sets of results. this agreement confirms that the proposed numerical model have the ability to estimate and predict the response and maximum load of gfrprc beam under different elevated temperatures up to failure. numerical simulation results reveal that the maximum load of gfrp-rc beams was found to be decreased by 1%, 8%, and 9% compared to the maximum load of control beam under exposure to a temperature of 350, 500, and 600 ºc respectively (see figure 10 and table 5).furthermore, table 5 shows comparison of failure load between numerical model and experimental tests comparison indicated very reasonable agreement can be seen between the two results. a) nc b) n350 c) n500 d) n600 figure 10 : numerical versus experimental load-displacement relationship of gfrp-rc beams exposed to different elevated temperatures. 142 nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 table 5 : comparison of failure load between numerical model (abaquse) results and conducted experimental results of gfrp-rc beams under exposure to high temperature. beam designation ultimate load(kn) experimental ultimate load(kn) abaquse % difference between exp. and num. results nc 174 170 2% n350 167 170 1.7% n500 147 155 5% n600 141 154 8.4 4. parametric study the validated numerical model was utilized to carry out a parametric investigation to demonstrate the effect of two important parameters on the performance gfrp reinforced concrete beams exposed to an elevated temperature which have not addressed in the current experimental study these parameters as follows: (a) effect of temperature time history. (b) effect of temperature distribution around the cross-section of the gfrp-rc beams. 4.1. effect of temperature distribution around gfrp-rc beams a temperature value of 600 ºc was considered in the current parametric study with three cases of temperature distribution: one side temperature exposure at the top layer of the section, one side temperature exposure at the bottom layer of the section and three sides temperature exposure in addition to the four sides exposure which is previously analyzed as shown in figure 11. load -displacement relationships of the beam n600 under above selected cases of thermal exposure were shown in figure 12. top section, bottom section and three sides’ temperature exposure results revealed increasing in maximum load by 11.5%, 13% and 13% respectively compared to maximum load of the beam n600 obtained from experimental test. the reason for this increase may be attributed to the resistance of unheated and undamaged layer of beam. the un-heated and un-damaged layer of the beam can resist more loading capacity than all heated beam layers due to un-deterioration of mechanical characteristic of unheated concrete and reinforcement bars. a) top layer exposure b) bottom layer exposure c) three side exposure d) all side exposure figure 11 : temperature distribution around gfrprc beam figure 12 : load -displacement relationships of n600 beam under different temperature distribution around beams 4.2. effect of temperature distribution along the gfrp-rc beams the investigated beam length was as follows: half-length exposed and three-quarter length exposed in addition to the full length exposure which is previously analysed of n600 beam as shown in figure 13.the loaddisplacement curves are shown in figure 14. the results of half exposed length shows increasing in ultimate load capacity by 7% compared to ultimate load capacity of full length exposure while, the results of threequarter length exposed shows very little decreased in ultimate load capacity by about 1% compared to ultimate load capacity of full length exposure case of n600 beam obtained in experimental study (see figure 14). this difference in the ultimate load capacity is due to the influence of hightemperature exposure on the mechanical characteristic of the exposed length of gfrp-rc beam. a) half-length exposure b) three-quarter length exposure c ) total length exposure figure 13 : temperature distribution along gfrp-rc beam figure 14 : load -displacement relationships of n600 beam under different temperature distribution along the beams. nuha hussien , haitham al-thairy /al-qadisiyah journal for engineering sciences 13 (2020) 136–143 143 5. conclusions the main conclusions and findings extracted from the numerical simulations carried out in this study were summarized as follows: 1. the finite element software abaqus/standard can reasonably predict the performance and ultimate load of gfrp-rc beams under different elevated temperatures if suitable geometrical, thermal dependent material and mechanical properties are selected and implemented correctly. 2. the distribution of the temperature around the gfrp-rc beam has a considerable effect on ultimate load of gfrp-rc beam. at the temperature of 600°c, when the temperature is distributed above one side (top section) , one side (bottom section) and three sides ,ultimate load capacity increased by 11.5%, 13% and 13% respectively 3. the distribution of the temperature over the length of gfrp reinforced concrete beam has reflected a slight effect on the maximum capacity of gfrp-rc beams. at temperature value of 600°c, the numerical results of the half temperature exposed length shows increasing in ultimate load by 7% compare with maximum load of full-length temperature exposure. while, the results of three-quarter length exposed shows very little decreased in ultimate load capacity by 1 %. references [1] m. saafi, effect of fire on frp reinforced concrete members, compos. struct. vol. 58, no. 1, pp. 11–20, 2002. [2] m.rafi, a. nadjai, finite element modeling of carbon fiber-reinforced polymer reinforced concrete beams under elevated temperatures, aci struct. j., vol. 105, no. 6, pp. 701–710, 2008. [3] b.yu , v.k.r. kodur, factors governing the fire response of concrete beams reinforced with frp rebars, compos. struct. vol. 100, pp. 257–269, 2013, doi: 10.1016/j.compstruct.2012.12.028. [4] a. abbasi, pj. hogg, a model for predicting the properties of the constituents of a glass fibre rebar reinforced concrete beam at elevated temperatures simulating a fire test, compos. part b eng., vol. 36, no. 5, pp. 384–393, 2005. [5] m. sakashita , y. masuda, k. nakamura , h. tanano , deflection of continuous fiber reinforced concrete beams subject to loaded heating in non-metallic (frp) reinforcement for concrete structures, proceedings of 3th international symposium, japan concrete institu, 1997. [6] t.d. lin, b. ellingwood and o. piet, flexural and shear behaviour of reinforced concrete beams during fire tests, u.s. department of commerce national bureau of standards centre of fire research gaithersburg, md 20899; november , 1988. [7] m. al-baghdadi, effect of high temperature on some properites of light weight concrete, matec web conf., vol. 138, no. 2, p. 01007, 2014. [8] iso 834. fire resistance tests elements of building construction. international organization for standardization; 1975. 1999. [9] a. abbasi , behaviour of gfrp-rc elements under fire condition, phd thesis, queen mary, university of london; june 2003, 2003. [10] m. rafi, a. nadjai and f. ali, finite element modelling of carbon fiber-reinforced polymer reinforced concrete beams under elevated temperatures, aci struct. j., vol. 105, no. 6, pp. 701–710, 2008. 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[16] y.c. wang, v.k.r. kodur, variation of strength and stiffness of fibre reinforced polymer reinforcing bars with temperature, cem. concr. compos. vol. 27, no. 9–10, pp. 864–874, 2005. [17] f. bulletin. frp reinforcement in rc structures.fédération internationale du béton, lausanne, switzerland; 2007. [18] m. rafi, a. nadjai and f. ali, fire resistance of carbon frp reinforced concrete beams. j.ournal of advanced concrete technology vol. 6, no. 3, 431-441, 2008. [19] a. abbasi, pj.hogg, fire testing of concrete beams with fiber reinforced plastic rebar. composites: part a 37 (2006) 1142–1150, compos. part a :appl. sci. manuf., vol. 37, no. 8, pp. 1142–1150, 2006, doi: 10.1016/j.compositesa.2005.05.029. [20] eurocode 4. design of composite steel and concrete structures–„en 1994.part 1-2: general rules structural fire design, (august), pp. 1109, des. compos. steel concr. struct. – part 1-2 gen. rules struct. fire des. no. august, 2005. 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[22] i. hibbitt, karlsson and sorensen, abaqus. abaqus standard user’s manual. vol. i-iii, version 6.8. pawtucket, 2008. appendix a table a.1: reduction factor of mechanical properties of gfrp bars t e n si le s tr e n g th [1 ] 𝑘𝑓= 𝑓𝑓𝑢,𝑇 𝑓𝑓𝑢,20°c , (t in °c) 𝑘𝑓=1-0.0025 t for 0≤ 𝑇 ≤ 400 𝑘𝑓=0 t for 400 ≤ 𝑇 m o d u lu s o f e la st ic it y [1 ] 𝑘𝐸 = 𝐸𝑇 𝐸20°c , (t in °c) 𝑘𝑓𝐸=1 for 0≤ 𝑇 ≤ 100 𝑘𝑓𝐸=1.175-0.00175 t for 110≤ 𝑇 ≤ 300 𝑘𝑓𝐸= 1.625-0.00325 t for 300≤ 𝑇 ≤ 500 𝑘𝐸 =0 for 500 ≤ 𝑇 s p e c if ic h e a t [3 ] c=(1.25+ 0.95 325 ƭ) × 103 for 20℃ ≤ ƭ ≥ 325℃ t h e rm a l c o n d u c ti v it y [ 3 ] 𝐾𝑓,ƭ = 1.4 + −1.1 500 ƭ for 20℃ ≤ ƭ ≥ 500℃ d e n si ty [ 3 ] ρ= ρ(20℃)= 𝑅𝑒𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 for 20℃ ≤ ƭ ≥ 510℃ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٤ effect of varying airgap length on performance of linear and non linear electromechanical relays abstract this work studies the effect of varying air-gap length on performance and behavior of electromechanical relays. when the air-gap length changed due to mechanical movement producing from air or liquid pressure in pneumatic or hydraulic system, respectively therefore; the magnetic reluctance is change, that is the inductive properties be effected and as a result of that, the switching value of voltage and current are changed drastically in electromechanical relays. it can be controlled on the min. and maximum value for air pressure in a pneumatic system by controlling on the minimum and maximum value corresponding to voltage and current in the system relay. two models of transducers are used in this study; the first is variable reluctance displacement transducer studies the intensity of magnetic field lines in 2-d, the intensity of magnetic field vectors and summation of magnetic field intensity contours estimated. the magnetic force is determined with airgap length changing from (0.8 to 0.2) cm, gradually. second model is variable differential reluctance transducer. the same results obtained in first model are determined in second model with two cases, armature in mid-way and armature shifted to right side by (0.4) cm. the magnetic force is determined along the line of axisymmetric and in y direction of armature location. the results show from ansys 5.3 and matlab 7 simulation, the magnetic field increases with decreases of air-gap length in first model and for the second model the magnetic field concentrated in mid way armature position and increase in the side where the air gap length reduced and reduced in the side where the air – gap length increasing. keywords: electromechanical relays; air – gap length; magnetic force, reluctance; magnetic field lines; vectors; ferromagnetic, ansys and matlab simulation. ��gh�ا ,� 6ت ا <�0و(�<��a<�� ا �'�� وا �6'��-�% أداء �3k ���dل ا &3iة ا 30ا!�� 9� ا �زاق -9�س ا '�ه���� ا �� ا ��اق/ o�(�� ����/ ;� ا 0/��� ا <��0�!�� ا �56� ����� ���� �� ��������������������� �� ��� ����� � �� ��� �� ��� !�"#� $�%. ����� '� $�% !�"#� ����� ��� ���(��� )* $ �+� �� � ��� %�, '� ��"�� ��������� ��� � �" �� ����������� -����� ��� . �/��0�� ����� 1��� ����� � �����#� ���/ ����� 1��� �"����� ��� � 2 �3� ��� ��4� ������ )�� ��+�%����� )������������ $ ��� ��� )* ali abdul razzaq al tahir electrical engineering department babylon university / iraq al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٥ (� �� $�5� .� '��� ���0� � ����� ���6� ��� !�%�+� 7��% '� ���0� ���(�� )* � ��� %�,� ���0� � ����� ���/ ��� !�%�+ �����#� �������� ��� !�(��� )* ��� $ ��� .�+ ��� 8�� )* ���3�+� ��++ ��� '� '������ 1����. �/��0� �+ �� �� $�9 �� :�� � !�"#�� �#��3� $ �%;� $�%� �����'��0�� � � )+�%����� <�#� %�%3 !�5 -�+ =�* > . )+�%����� $�"�� !�5 ���"��� .�/�0� � � ��#� ��� <0�� $�"�� !�/ -�+ �� �*�,� ' ��9 ?��� ��+� ��� )+�%����� $�"�� !�5�. '� '� !�"#� ����� �"��� ��� ��+%����� !�6� )a.b�� a.c (>+��"���� .$����� )��,�#� �/��0� �+ ���� )���� ����� )* !�� 1� ��� �e"�� '�#��3� '�0/��������� f�3� !��� '��#��� '�� 7��%� g�e� � �6�� '���� �� )a.c(>+ . �6� * ������� )6*9 �(���� %3 $�% ��� )+�%����� $�"�� !�/ -�+ �� �*�,� )���� $����� )* 2 �3� �#� -�+ >� ) �� ��� !�"#� �6%�� .h ���� ���(� !��� �� '� ���� � d�f. ansys"��ة qِ�")�f ا �4"آ"ة � ��9 i.j و > �3�+;� k��+� � ��9 ��*�#��� ���3� ��"���� ��e � 8�"#� $�% '��6� k� � �e� )+�%����� $�"�� !�/ '� $�9 $������ ��+���� ��� �� ��� $�����)���� .�6* )* � �e�� $ ���� 1� ��� �e"� -�/ e����� )+�%����� $�"�� !�/ '� h ���� ���(� !�"#� $�% ���* � �e� )�� ��"� )* $��6���� $6�� �� ��� !�"#� $�% ���* $6� )�� ��"� nomenclature symbols definitions units a the cross sectional area of flux path cm 2 b magnetic flux density tesla or (wb / m 2 ) d damping coefficient em f the electromagnetic force n load f the pneumatic force n fa the mechanical load n h magnetic field intensity a / m l the total of winding inductance in coil h l the total length of the flux path cm m mass of the moving part g n number of turns turn r radius cm s surface arc length cm t the maxwell stress tensor t switching time sec. v supply voltage volt v armature velocity /sec.m x air – gap distance cm λ magnetic reluctance (amp.turn) / wb µr relative magnetic permeability h / m µ0 free space absolute permeability (4 π * 10 -7 ) h / m ψ magnetic flux linkage wb. turn ф magnetic flux wb introduction the relay is a device for amplifying, attenuating modifying, or passing (on/off) signals. relays can be classified to electric, electronic, pneumatic, hydraulic, balanced beam differential or optical and they may have many different functions such as over current, over voltage, differential protection and electro-mechanic contactor after occurs a disturbance like trip, fault or d.c clock signal [holman, 1997] . the contactor is a switching device, which connects (on) or isolates (off) a load from the supply. the al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٦ mechanical contactor requires an operating movement and operated by tenderization of the magnetic spring carrying the contacts. the most common traditional form of relay is the electromechanical relay, which utilizes an electromagnetic coil, to move a plunger or an armature for open or close electrical contacts. the transducers can be adjusted by electromechanical motion produced from electrical signal air or liquid pressure in electrical, electronic, pneumatic or hydraulic systems. the mechanical motion may be design in different forms such as armature and spring motion. eelectromagnetic relay designed to switch (on / off); like in circuit breakers in all types and pressure valves. application like large force is applied to a member, which moves a relatively short distance through the conversion of electrical energy into optimum mechanical work from magnetic attraction. the electromagnetic relay must have three features, which are compact electromagnetic, high speed and light weight. the magnetic circuit consists of a core made of a ferromagnetic material, with a coil of several number of wound on it. the coil acts as a source of magneto motive force, which drives the magnetic flux through a magnetic circuit. the presence of air gap causes large increase reluctance and corresponding decrease in the flux, a small variation in air gap results, a measurable change in inductive properties. most of the inductive transducers are based on these principles [doebelin, 1992] . the effect of alternating current in a distribution coil on magnetic flux density has been analyzed and discussed. it provides a theoretical basis for selecting the reasonable technology parameters [wang, and cui, 2005] . for apparatus with two stable positions of the moving part dynamics of opening and closing is of interest, in this case the duration of the process to be simulated is short, most often of order of milliseconds. for devices with continuous motion, although the dynamics determines the normal region of the devices on the period of the mechanical oscillation and the simulation should cover several periods [ando and ishikawa, 2001]. in presence of a linear material properties, this leads straight forward to the expression of the maxwell stress tensor as well as to that of classical formulae obtained by the virtual work principle, thus making the link between them obvious [ren, 2001] . the present paper, deals with a linear and non – linear relays and different models using, ansys vol. 5.3 [ansys, 2002] and matlab vol.7, simulations [math works, 2006] in electromichanical couple relays will be presented together with methods for analysis to the problem. mathematical models numerical solution is performed by finite element approach using ansys program vol. 5.3. two models of transducers are studied. the central magnetic flux path is shown in figure 1, which represents the first model, consists of four elements, which are a variable air gap, ferromagnetic core in the semicircle shape ring (stationary part), coil, and ferromagnetic plate (armature), which is the moving part. the magnetic reluctance of the core in this model is dependent on varying air – gap length. the magnetic flux path is shown in figure 2, which represents the second model consists of an armature, moving part between two identical cores separated by a fixed distance of (0.4) cm. the armature moves in the air gap in response to a mechanical force. this movement alters the magnetic reluctance of cores that is altering their inductive properties. the second model arrangement overcomes the criterion of non-linearity in first model. the direction of magnetic flux lines, in two models, can be determined by using right hand screw rule [www.sayed.com] . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٧ model of each transducer in figures 1 a and 2 a are analyzed as a two dimension axisymmetric model. for given clock pulse and current in first model figure 3 a, the two dimensions flux lines contour, magnitude of flux density contour, flux density as vectors. magnetic force, energy input, winding inductance, current per turn, and flux linkage will be presented for (0.8, 0.6, 0.4, and 0.2) cm of air – gap varying length, gradually. for given clock pulse and current in second model figure 3 b, the two dimension flux lines contour, magnitude of flux density contour, flux density as vectors. magnetic force, energy input, winding inductance, current per turn, and flux linkage will be presented for two positions of the plate armature, the first is in the center between two cores and the second is shifted to the right side by (0.2) cm and not shifted to the left side due to axisymmetry model around y axis. figures 1b and 2 b illustrate the electrical series equivalent circuits for variable reluctance displacement and series – parallel axisymmetric variable differential reluctance modelss, respectively. there are several assumptions are made to simplify the solution of two models such as: 1all material properties (resistively and permeability) are linear. typical hysteresis curve (loop) in magnetic circuits is shown in fig. (4), which represents the relation between magnetic flux and current. the magnetic materials have important role in effecting on (b – h) curve configuration. the electric and magnetic properties of ferromagnetic materials are described by the resistively of the material and the nonlinear relationship of the flux density, b and the magnetic field strength, h. 2the air gap is modeled so that the quadrilateral is possible. 3the magnetic force is calculated by virtual work and maxwell stress tensor methods. 5no saturation in iron occurs due to the small magnetic flux produced from the coil current. 6the external flux leakage is negligible, which means that the magnetic flux lines will act parallel to the core surface. if assume the air-gap length is zero the equation of magnetic circuit can be expressed as [zhang and cui, 2002] : m. m. f = magnetic flux * reluctance = ф * λ (1) such that the magnetic reluctance limits the magnetic flux path in magnetic circuit. if the magneto motive force in terms of current and number of turns, the magnetic flux can be expressed as: ф = n. i / λ that gives, λ = l / (µo µr. a) (2) the mechanical motion equation formed if, the armature is displaced a distance dl at the air-gap due to the magnetic field force acting on it, the magneto static energy must be equal the input mechanical work done for two dimensions x and y axis forces : .dyf.dxff.dldw yxm +== (3 a) while, the mechanical work done would be in three dimensions x, y and z axis forces: dz.f.dyf.dxff.dldw zyxm ++== (3 b) this work is done by supply voltage v volt at the expense of energy in the magnetic field such that the following energy balance is maintained that the magneto static energy change plus the mechanical work done equal to work done by the supply voltage v. the change in the magnetic energy , changing the air – gap length. the magneto static energy is: al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٨ 22 m . 2 1 2 1 l.i 2 1 w φλ=ψ== i (4 a) the stored energy in air gap is: wair gap= gapalbh . 2 1 (4 b) omitting the heat losses coil 2 .ri associated with coil resistance in the equivalent circuit of a certain system. in the basis of the balance of the forces acting on the moving part: loadem2 2 ff dt dx d. dt xd m. −=+ (5) to reduce the order of derivatives in the force equation (5), the latter is split into two equations [edward and michael, 2001] : and the velocity is: dt dx =v (6) the property of self inductance is a particular form of electromagnetic induction. self inductance is defined as the induction of a voltage in a current – carrying wire when the current in the wire itself is changing. it can be seen that the number of turns in the coil will have an effect on the amount of voltage that is induced into the circuit, i.e., increasing the number of turns or the rate of change of magnetic flux increases the amount of induced voltage. there are several methods can be represented the total winding self inductance in the coil: x k x a.µ .n n i l r02 2 == λ === µψφ i n (7) the steady state equation is: x)k.( ξf x i . 2 k a2 2 −+= (8) the dynamic equations are: the applied voltage in electrical circuit is depending on coil induced voltage and drop voltage on coil resistance: v = er.i + (9) em2 2 a f dt dx dξ)k(x dt xd mf −+−+= (10) the induced voltage in the relay coil can be calculated: dt dx . x i k. dt di . x k dt dx . dx dl i. dt di l. dt d e 2 −=+= ψ = (11) there exist two distinct families of electromagnetic force formulae. the ones belonging to the first family are based on the maxwell stress tensor while the other ones from the application of the virtual work principle. according to the virtual work method, considers the rate of the change of the total coenergy against the virtual displacement: x xw f c em ∂ ∂ = )( (12) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٩ according to maxwell’s stress tensor method, from the energy density of the fields there is a momentum density one can show that: dsnbbnbf s em ]. 2 1 ).[( 1 2 0 −= ∫ µ (13) the maxwell’s stress tensor t is a circle integral of: dsnbbnbrt s ]. 2 1 ).[( 1 . 2 0 −= ∫ µ (14) where, n is the number of nodes on surface. 3 results and discussion 1: variable reluctance displacement transducer fig. 5-a represents the finite element mesh model of the first type. the number of the finite elements for each case at (0.8, 0.6, 0.4, and 0.2) cm of air gap length are (3238, 3235, 3231, and 3228), respectively. the results are obtained for the transducer from figure 1 with the following data: supply voltage is (12) v; coil resistance rcoil is (8) ω; number of turns is (400); mass of the moving part is (35) g., damping coefficient is (25), cross section area of (0.785) cm2 and current density of (127. 388 * 10 6) a / m2. the following results consist of two parts, which are qualitative results and quantitative results [ansys program, 2002] : aqualitative results: figures. 5 -b, 5-c and 5-d) illustrate the 2-d flux lines contour, magnitude of flux intensity contour, and flux intensity as vectors at (0.8) cm air gap length. the maximum flux, flux intensity, and flux intensity vectors in these figures are (0.0576, 0.119976, and 0.119034), respectively. figures. 6-a, 6-b, and 6c show the 2-d flux lines contour, magnitude of flux intensity contour, flux intensity as vectors at 0.6 cm air gap length. the maximum flux, flux intensity, and flux intensity vectors in these figs are (0.0577, 0.120289, and 0.11928), respectively. flux intensity, and flux intensity vectors in these figs are (0.0578, 0.120124, and 0.119186), respectively. figures. 7-a, 7-b, and 7c indicate the 2-d flux lines contour, magnitude of flux intensity contour, flux intensity as vectors at (0.4) cm air gap length. the maximum flux, flux intensity, and flux intensity vectors in these figs are (0.0578, 0.120124, and 0.119186), respectively. figures.8-a,8-b, and 8-c show the 2-d flux lines contour, magnitude of flux intensity contour, flux intensity as vectors at (0.2) cm air-gap length. the maximum flux, flux intensity, and flux intensity vectors in these figures. are (0.058, 0.12047, and 0.119386), respectively. these results indicate increasing of the flux, while increasing and then decreasing of the flux intensity magnitude and increasing of the flux intensity vectors with the decreasing of the air gap length from (0.8 0.2) cm. bquantitative results: figures. 9 a & 9 b show the behavior of magnetic force along the line of x symmetric and along y axis at the armature position; respectively. the first curve shows that the maximum magnitude of this force is between the (3.576 and 4.2) cm, which means at the armature position. the second curve indicates that the maximum magnitude of the magnetic force is at the air gap positions and the force at the upper air gap is greater than at the lower one. the behavior of magnetic force produced by virtual work and maxwell stress tensor method, energy input, al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٠ winding inductance, current per turn, and flux linkage with the air gap length are summarized and tabulate in table 1. the results indicate strong increasing in force by the two method used with the decreasing in the air gap length, while a small increasing in the energy input, winding inductance, and flux linkage with the decreasing in the airgap length, and the fluctuating mode produced in the current per turn behavior. the results conclude that the variablereluctance transducers are based on the change in the reluctance of the magnetic flux path. this type of transducer finds application particularly in acceleration measurements and it can be constructed to be suitable for sensing displacement as well as velocities. the total reluctance of the magnetic circuit is the sum of the individual magnetic reluctances: a λ+λ+λ+λ=λ lcgtotal (15) where: alcg and,, λλλλ are the magnetic reluctances of the air gap, core, coil and armature (moving part). or, r.tµµ r r2µ r rµµ r πrµ 2.dl a armature 2 coil 2 c c 2total oooo +++=λ ore (16) the total length of the flux path in air gap is changing as non – linear and from two side of gaps (2.dl). the cross section area of the flux path in air gap is represented as circle area ( 2πr ). the flux path length of the core is taken as circle circumstances ( πr ) and the cross section area is ( 2πr ). the flux path length of the coil is ( 2πr ) and the cross section area is constant ( 2πr ). the length of the flux path in the armature is (2r) and the cross section area is (2r.t), where t is the thickness of the armature. despite of this non-linearity criterion, these types of transducers have applications in several areas, such as electromagnetic force measurements. in force measurement, the change in inductance can be made to be measure of the magnitude of the applied force. figure 10-a illustrates matlab simulation for variable reluctance displacement transducer, fig. 10 b show mechanical and electrical forces versus time offset, figure 10 c shows air – gap length versus time offset and figure 10 d shows armature current versus time offset [math works, 2006] . the relative permeability for all three sections, which are air – gap, cast iron core and armature in first model are (1, 1100 and 2000) h / m, respectively. error in force calculation using two methods, which are maxwell stress tenser represents an electrical force in nine directions and virtual work represents mechanical force in two directions, is coming from the fundamentals physic for each method, although maxwell stress tenser method gives more accurate in results than virtual work. it’s evident from figure 10 – d the operating current varies between (0.45 – 0.55) amp, which represents the actual operating current for switching (on / off) states. figure 11-a represents the finite element mesh model of the second type. the number of the finite elements for each armature positions at the mid – point and right are (535 and 531), respectively. the results are obtained for the transducer from figure (2) with the following data: supply voltage is (12)v ; coil resistance rcoil is (10 ) ω; number of turns is (600) for two coils; mass of the moving part is al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢١ (25) g., damping coefficient is (20) and cross section area of (0.785) cm2 and current density of (127. 388 * 10 6 ) a / m2.. the following results consist of two parts, which are qualitative results and quantitative results [ ansys program, 2002] :: a qualitative results: figures. 11 b, 11 c and 11d, illustrate the 2-d flux lines contour, magnitude of flux intensity contour, and flux intensity as vectors at the first armature position. figures. 12 b, 12-c and 12-d illustrate the 2-d flux lines contour, magnitude of flux intensity contour, and flux intensity as vectors at the second armature position. these results indicate increasing of the flux, while decreasing of the flux intensity magnitude and decreasing the flux intensity vectors with the changing of the armature position at the center position and shifting by (0.2) cm to right side and not shifting to left side due to axi symmetric model. b quantitative results: figures. 13 a & 13 b show the behavior of magnetic force along the line of x symmetric and along y axis at the armature position respectively. the first curve shows that the maximum magnitude of this force is between (1.35 and 2.561) n, which means at the armature position. the second curve indicates that the maximum magnitude of the magnetic force is at the air gap positions and that the force at the upper air gap is greater than that at the lower one. the energy input, winding inductance, and flux linkage with the armature position change variable differential reluctance transducer are summarized and tabulate in table 2. the relative permeability for all four sections, which are air – gap, cast iron core, coil and armature in second model are (1, 1100, 2000 and 3000) h / m, respectively. error in force calculation using two methods, which are maxwell stress tenser represents an electrical force in nine directions and virtual work represents mechanical force in two directions, is coming from the fundamentals physic for each method, although maxwell stress tenser method gives more accurate in results then virtual work. matlab simulation for variable differential reluctance transducer can be repeated for same procedure and tests except the inductive properties and criterion of varying air gap length, depending on mathematical equations starting from eq.(7) to eq.(12). in case two the iron core is located in mid way between the e shaped frames. the flux generated by primary coil depends on the magnetic reluctance of the magnetic path, the main reluctance being the air gap. any motion of core increases the air gap on one side and decreases the air gap on the other side, thus causing reluctance to change, in accordance with the principles explained above, and thereby including more voltage on one of the coils than on the other. motion in the other direction reverses the action with ( o 180 ) phase shift occurring at null. the output voltage can be modified, depending on the requirement in signal processing by means of rectification, or filtering. in general, variable reluctance transducers have a small range and are used in specialized applications such as pressure transducers. magnetic forces imposed on the armature are quit large and this severely limits their application. however, the armature can be constructed as a diaphragm, which is suitable for air pressure measurements. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٢ conclusions 1this study allows fast multiple analyses for a certain supply voltage and external circuit parameters, which can be especially useful at the stages of electromechanic relay design and manufacturing. 2the results show from ansys and matlab simulation for second model, the magnetic force concentrated in mid way location armature and magnetic force increase in the side, where the air gap length reduced by (0.2) cm and finally, reduced in the side, where the air-gap length increased by shifting the armature location to the right side by (0.2) cm. 3the mechanical motion change the airgap length, which changes the reluctance of the magnetic circuit and then the inductive properties will be changed. the maximum and minimum motion can be controlled by maximum and minimum (switching voltage and current) magnitude setting. 4material properties like (resistively, which increases with increasing temperature degree and magnetic permeability) and dimensions geometry for different parts of relay can be affected on the magnetic properties such as the magnetic force, flux linkage and then on the response time offset. the performing procedures on the two models can be generalized for the other types of transducers. 5the results show from simulation for first model, the magnetic flux density increases with decreasing in airgap length. also, magnetic field intensity concentrate near coil location and decrease as far as from coil position, as shown from ansys simulation, the colures density grading from red, yellow, green and blue, for two models. 6increasing air gap length with time offset for linear and non – linear transducers can be discussed or proved due to the cyclic maintenance and crashing the external surface area of the moving contacts (due to arc or spark effect) to increase the operating life time, that is the performance, behavior, magnetic force, inductive properties and efficiency of the electromechanical relays will be decreased and demagnetized. 7the running time for ansys simulation in two models (linear and non – linear) is approximately ten minutes, which dependents mathematically on finite element method fem for (2 – d) model, while the running time for matlab simulation in two models (linear and non – linear) is approximately four minutes, which dependents mathematically on ordinary differential equations like (ode 23 and ode 45). references ansys program, 2002, “documentation vol. 5.3”, ansys, inc, software package. ando, r. and ishikawa, t., 2001, “development of a simulation method for dynamic characteristics of injector”, ieee trans. magnetizing, vol. 37, no. 5, pp. 3715 – 3718. dublin, e., 1992, “measurement systems: application and design”, 4th edition, new york, mcgraw hill. edward, j. and michael. j, 2001,” electromagnetic”, electrical engineering textbook series by crc press.org. holman, j., 1997,”experimental methods for engineers”, 5, th edition, new-york mcgraw hill. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٣ math works, 2006, “matlab vol. 7.0 ", release 14, jun 18, http://www.mathworks.com. ren, z., 2001,” shell elements for the computation of magnetic forces”. ieee trans. on magnetics, vol. 37, no. 5, pp. 359 – 364. wang, z. and cui, j., 2005,” numerical simulation of magnetic field for electromagnetic casting of hollow billets”, july 2005, vol. xxvii, no. 3, pp. 325 328. zhang, b. and cui, j., 2002, “numerical simulation of magnetic field of electromagnetic casting of aluminum casting”, the chinese journal of non ferrous metals, vol.12, no.3, pp.112 115. zainal, s.,2007,” power electronics and drives, version two”, http://www.sayedsaad.com. table 1: the energy input, winding inductance and flux linkage with armature position change in first model. air gap length (cm) force (n) virtual work * 2 10 force(n) maxwell stress tenser * 2 10 energy input (j) *10 -3 winding inductance (h) *310− switching current (amp.) flux linkage (wb. turn) * 4 10 − 0.8 0. 30546 0. 30617 0. 509591 2.100452094 22. 0276453 1.1567029 0.6 0. 36323 0. 36414 0. 5102544 2.103181693 22. 0277407 1.1582085 0.4 0. 44228 0. 44352 0. 5110568 2.106498103 22. 0276953 1.1600324 0.2 0. 56572 0. 7101 0. 5120542 2.110600753 22. 0277407 1.1622941 table 2: the energy input, winding inductance and flux linkage with the armature position change in second model. armature position force (n) virtual work * 2 10 force (n) maxwell stress tenser * 2 10 energy input (j) * 3 10 − winding inductance (h) * 3 10 − switching current (amp.) flux linkage (wb.turn) * 6 10 − mid-way 0. 50352 0. 48924 2. 52006 5. 0401284 0.9 8. 400244 (0. 2) cm shifting to right 0. 22721 0. 22480 2. 76194 5. 5238866 0.9 9. 206477 fig. 1-a: single coil, variable reluctance displacement transducer. x coil 12v fig. 2 a: two coils variable differential reluctance transducer. x coil 2 coil 1 12 v moving part moving part stationary part stationary part al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٤ x line of symmetric fig. 3-a: 2-d axisymmetric model for first model. yline of symmetric 0.135 0.12 0.1 0.125 0.135 0.085 0.095 armature air gap coil core coil 0.01 0.008 fig. 3-b: 2-d axisymmetric model for second model. a rm a tu re corcor coil 1 coil 2 core core 0 .7 5 3 3 ..5 3 .9 4 .3 4 .7 5 ..3 7 .3 7 5 5 8 .2 1 cm m 1 1.5 3 3.5 4.25 air gap fig.1b: electrical series equivalent circuit for variable reluctance displacement model. ~ n i λ coil λ gap λ core λ armature ~ n i λ core λ core λ gap 3 λ armature λ gap 2 λ core λ gap 1 λ armature fig.2b: electrical series – parallel equivalent circuit for axisymmetric variable differential model. fig. (4): typical hysteresis curve in magnetic circuits remanence saturation al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٥ fig. 5 b: shows the magnetic flux lines. fig. 5 a:shows the finite element model in first model. fig. 5 c: show the magnetic field intensity summation contours. fig. 5 d: show the magnetic field intensity vectors at air gap of (0. 8) cm length. fig. (6 a): show the magnetic flux lines. fig. (6 b): show the magnetic field intensity summation contours. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٦ fig. 6 c: shows magnetic field intensity vectors at air gap of (0. 6) cm length. fig. 7 a: shows the magnetic flux lines. fig. 7 b: shows magnetic field intensity summation contours. fig. 7 c: shows magnetic field intensity as vectors at air -gap of (0. 4) cm length. fig. 8 a: shows the magnetic flux lines. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٧ fig. 8 b: shows magnetic field intensity summation contours. fig. 8 c: shows magnetic field intensity vectors at air gap ( 0. 2 ) cm length. fig. 11 a: shows the finite element model in second model. fig. 9 a: shows the behavior of magnetic force in first case of (0.8) cm a long line of x symmetric, in item (3-1). fig. 9 b: shows the behavior of magnetic force in second case a long of y axis, in item (3 1). . cl ock pulse mechanical force 0.003 xsi 12 supply voltag u 2 square i /x force current air gap l ength linkage current 10 r product 2600 k 1 sxo 1 s 1 s [8 25] d 1/6.3e-5 1/k -k1/m -k-k/2 e i f em u f a x fig. 10 a: matlab simulation for variable reluctance displacement transducer. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٨ fig. 11 b: shows magnetic flux lines in second model. fig. 11 c: shows magnetic field intensity summation contours. fig. (10 c): shows effect of varying air gap length versus time offset for first model. fig. (10 d): shows effect of switching current versus time offset for first model. fig. 10 – b: shows effect of mechanical and electromagnetic forces versus time offset for first model. fa fem al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٢٩ fig. 12 c: shows the magnetic field intensity vectors when the position of armature is shifted by (0. 2) cm to the right side. fig. 12 b: shows magnetic field intensity summation contours when the position of armature is shifted by (0.2) cm to the right side. fig. 11 d: shows magnetic field intensity vectors when armature at the mid way. fig.12 a: shows the magnetic flux lines al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣٠ fig.13 -b: shows the behavior of magnetic force in second case a long y axis at mid -way between two cores starting from the bottom, in item (3 2). fig. 13 -a: shows the behavior of magnetic force in first case a long x symmetric at mid way between two cores starting from the bottom, in tem (3-2). fig. 14-a: matlab simulation for variable differential reluctance transducer. pulse clock supply voltage 0.003 xsi 12 v u 2 square i/x gap length force current lambda i 12. r product 2499 k 1 sxo 1 s 1 s -kd -k1/k -k1/m -k-k/2 e i f e lambda u f a xxx al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٣١ fem fa fig. 14-b: shows effect of mechanical and electromagnetic forces versus time offset for second model. fig. 14-c: shows effect of varying air – gap length versus time offset for second model. fig. 14-d: shows effect of switching current versus time offset for second model. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 177 optimum hydraulic and structural design of inverted siphon dr. haider k. ammash college of engineering university of al-qadisiya thulfikar r. alhusseini college of engineering university of al-qadisiya munaf a. alrammahi college of engineering university of al-qadisiya abstract in the present study, the optimum hydraulic and structural design of inverted siphon has been studied. modified hooke and jeeves method considered in the present study and some modifications were doing. these modifications are:1) modification on the assumed initial base points, 2) modification on the value of step length, 3) modification on the value of the reduced step length at each trial. many shapes of inverted siphon considered as (circular section, square section, and rectangular section). a computer program was writing by fortran90 language depending on the method mentioned. staad pro2006 software program was considering to structural analysis and design of inverted siphon. many examples solved to check the accuracy of the written program. keywords: optimum, hydraulic, inverted siphon, structural design, reinforced concrete ا�� (�س ��r�)�نا< g' واm���r� ا��d��4 ا�,��رو��(� 23ي ا�)����� �ف 2e1 ا�� �2 آ* ا�3 ����� ا���د � ذو ا���bر رزاق ا��� �2 آ* ا�3 ����� ا���د 2ر آ�?> ��1ش.د� �2 آ* ا�3 ����� ا���د ا�567 d=) modified hooke and ا�f���cد ��w �f��fp$ . ا< g' واm���r� � ه&ا ا� �� =d درا�y ا��d��4 ا�,��رو��(� (jeeves �f� l 5 ? ا�� �$�ت ا��� أe�$] ���,� -�ل هf&ا ا� . �f�� ت�$�f ا�� zf�= أن �&fأ� ه �fp$�q �,4f�x�= /f)�$ �ff=��:١ �ff� = �ff$�ت ���ff��j �ff ا��ffqxة -٣ = �ff$�ت ���ff��j �ff ا��ffqxة -٢ = �ff$�ت ���ff ا��ffqp2 ا��5cا�ff�m ا��)�و �fو��� 'fآ � � �gا�� �g(xا��. /f �f$� ك ا��f2ل ه�)fy>أدر ا [fe ،lf5�ي، ا���mا�fا� lfqpا�� 'fg ���rf$)�ن ا�� (�fس '�q�rا��. df= اد�fإ� �fi�5 ffy�� k �f��5 " fortran90" �fp$�w �f�� د�f���c�5)modified hooke and jeeves ( rff�� 'ffg�)�ن cا �رو��(�ff�,ا� d��4ff��� . k �ff��5 �ff�� س�ff) ن ا���(�rff�� �m��ff�rا d��4ffوا�� 'ff�ا���� �ff د�ff���cا dff= )staad pro2006(k ��� ����� �x�y�5ام ه&ا ا� ��g �; ��ة أq= d=آ� ا��(��ب وs��� z�jد / . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 178 nomenclature b: span of box section (m) d:diameter of pipe (m) ca: constant for showing irrigation canal (ca=1) or drainage canal (ca=2). d: height of box section (m) f: lacey silt factor (m) f1:coefficient of head losses at entry (m) f1: constant for elbows losses. f2 : is a coefficient such that the losses of head through the barrel due to surface friction, f2: constant for bend losses hf : the total head losses which equals to the difference between the upstream and downstream water level (m). k1:entrance coefficient (m) k2:outlet coefficient (m) kcon:contraction coefficient (m) ke: entrance coefficient. kel: elbows coefficient ko: outlet coefficient. kex:expansion coefficient (m) ks: screen coefficient l: length of inverted siphon (m). q:discharge / meter width (m 3 /m.s) q: discharge (m 3 /sec). r:hydraulic mean radius of the barrel (m) r1:depth of scour below water level (m) s: the slope of siphon (dimensionless). v:velocity of flow through the barrel (m/s) va:velocity of approach and is often neglected (m/s) vc: velocity of canal (m/sec) zcb:cost of construction for concrete box (i.d) zcp:cost of construction for concrete pipe (i.d) zs:cost of construction for steel pipe (id). y: elevation of water (m). ye: depth of water in canal (m). introduction highways and railroads traversing the land cut across individual watersheds. to allow the flow from each watershed across the embankment, culverts, siphons and aqueducts are used. although these structures simple in appearance, their hydraulic design is no easy matter. the operation of these structures under the various possible discharge conditions presents a somewhat complex problem that cannot be classified either as flow under pressure or as free surface flow. the actual conditions involve both of these concepts. hydraulic structures employed to convey, control, measure and protect the flow of water at various locations in an irrigation and drainage system. there are many different types of structures can be used for these purposes though individually they may be small or large. structures can contribute to a large part of the overall capital cost of an irrigation project; hence, a proper design of these facilities is a major factor in making the scheme al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 179 efficient and keeping capital costs to a minimum. the final design must take into consideration the practices and farming methods in vogue and should endeavor to meet the requirements of the farmer and thereby enlist his co-operation. this will minimize maintenance costs by minimizing mis-use and vandalism. other factors that affect the design and operation of irrigation structures include site conditions, the methods employed for the conveyance of water and the availability of construction materials. only the smaller sizes of structure are amenable to having the design procedure standardized. purpose and description of inverted siphons inverted siphons used to convey canal water by gravity under roads, railroads, other structures, various types of drainage channels, and depressions. a siphon is a closed conduit designed to run full and under pressure (aisenbrey, et al., 1974) (1) . the structure should operate without excess head when flowing at design capacity. a-application economics and other considerations determine the feasibility of using a siphon or another type of structure to accomplish the previous objectives. the use of an elevated flume would be an alternative to a siphon crossing a depression, drain channel or another manmade channel. the use of bridge over a canal would be an alternative to a siphon under a road or a railroad. b-advantages and disadvantages of inverted siphons inverted siphons are economical, easily designed and built, and have proven a reliable means of water conveyance. normally, canal erosion at the ends of the siphon is inconsequential if the structures in earth waterways have properly designed and constructed transitions and erosion protection. costs of design, construction, and maintenance are factors that may make an inverted siphon more feasible than another structure that might used for the same purpose. there may be, however, instances where the value of the head required to operate a siphon may justify the use of another structure such as a bridge (aisenbrey, et al., 1974) (1) . an inverted siphon may present a hazard to life, especially in high population density areas. structure components the siphon profile is determined in such a way as to satisfy certain requirements of cover, siphon slopes, bend angles, and submergence of inlet and outlet. siphon cover requirements are (aisenbrey, et al., 1974) (1) : 1) at all, siphons crossing under roads other than farm roads and siphons crossing under railroads, a minimum of (0.91 m) of earth cover should provided. farm roads require only (0.61 m) of earth cover and are frequently ramped using 10 to 1 slopes (10 percent grade) when necessary to provide minimum cover requirements. if roadway ditches exist and extended over the siphon, the minimum distance from the ditch to the top of the pipe should be (0.61 m). 2) at siphons crossing under cross-discharge channels, a minimum of (0.91 m) of earth cover should provided unless studies indicate more cover is required because of projected future retrogressions of the channel. 3) at siphons crossing under an earth canal, a minimum of (0.61 m) of earth cover should provide. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 180 4) at siphons crossing under a lined canal, a minimum of (0.15 m) of earth cover should provide between the canal lining and the top of siphon. roadway widths and side slopes at road and railroad siphon crossings should match existing roadway widths and side slopes, or as otherwise specified. side slopes should not be steeper than (1-1/2 to 1). siphon slopes should not be steeper than (2 to 1) and should not be flatter than a slope of (0.005). hydraulic design considerations available head, economy, and allowable siphon velocities determine the size of the siphon. thus, it is necessary to assume internal dimensions for the siphon and compute head losses such as entrance, friction, bend, and exit. the sum of all the computed losses should approximate the difference in energy grade elevation between the upstream and downstream ends of the siphon (available head). in general, siphon velocities should range from (1.07 m/s) to (3.05 m/s), depending on available head and economic considerations (aisenbrey, et al., 1974) (1) . the following velocity criteria may use in determining the dimensions of the siphon: 1) (1.07 m/s) or less for a relatively short siphon with only earth transitions provided at entrance and exit. 2) (1.52 m/s) or less for a relatively short siphon with either a concrete transition or a control structure provided at the inlet and a concrete transition provided at the outlet. 3) (3.05 m/s) or less for a relatively long siphon with either a concrete transition or a control structure provided at the inlet and a concrete transition provided at the outlet. where there is reasonable, confidence that a good standard of construction will achieve the upper limit of velocity through a siphon may take as (3 m/s), where doubts exist as to construction quality this figure may be reduced to (2 m/s),(jawad, kanaan, 1983) (5) . to avoid sedimentations, the minimum velocity that considered is (0.6 m/s). for discharges up to about (2.5 m3/s), pipes can be used but for larger discharges a box section is preferred, (jawad, kanaan, 1983) (5) . for future increase in demand, it is usual to design all canal structures for (1.2 q) where q is the design flow during the period of maximum demand. the minimum design flow is usually taken as (0.7 q), blow this value, there is the risk that sedimentation will occur due to low velocities. for drainage structures, the maximum flow taken as (1.5) times the design flow. minimum flow does not apply to drainage structures, (jawad, kanaan, 1983) (5) . the most common materials used for culverts are concrete and corrugated steel. the roughness in both cases usually assumed constant for any flow depth. on hilly terrains where the culvert slope expected to be relatively steep and the flow through the culvert gains considerable energy, corrugated steel pipes offer energy-dissipating advantages. on flat terrains, energy loss through a culvert is undesirable; hence, concrete pipes are more suitable (simon, 1997) (9). for design purposes in iraq, concrete and steel pipes considered with roughness coefficient (n) equal to (0.014) and (0.01) respectively(jawad, kanaan, 1983) (5). drainage structures must checked against piping, uplift pressure, erosion at upstream, downstream, and protected against sulphate attack on concrete. the protection consist of (0.4 × 0.4 × 0.2 thick m) concrete blocks over (0.1 m) gravel bedding for length (2 × d) of the barrel for upstream. downstream is similar for length (3 × d). depth of scour in unlined canal can be calculated from lacey formula and compared with (2 × d) and (3 × d) (jawad, kanaan, 1983) (5) . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 181 0.33 2 1 f q 1.35=r         ×××× (1) where: f : lacey silt factor can obtained from table (1) which used for iraq. flow of depth -r 1.5= d 1s ×××× (2) ds1.5= protection of length ×××× (3) to ensure inlet submergence the invert of the siphon section should be dropped so that d greater than the elevation of water at the canal with the drop at the siphon entrance with slope (1 to 5 (v:h)) which generally equal to (0.5 m). so the discharge will divided into 2,3,4,….etc, to satisfy the previous condition, and that means the siphon sections equal to 2,3,4,…etc. reinforced concrete rigid frame box culverts with square or rectangular opening are use up to spans of (4 m). the height of the vent generally does not exceed (3 m). adopting thickness of slab as (100 mm/ meter span) (simon,1997) (9) . head losses of inverted siphon total head losses equal to the sum of the friction, entrance, exit, screens, elbows, transitions and bends losses. the minimum overall head loss for inverted siphons is (0.2 m) (jawad, kanaan,.1983) (5) . losses through siphon can calculate by using the following formula (garg, santosh , 1978) (4) : conex hh g va g v ksff r l ffh ++++++++−−−−      ++++++++++++××××++++++++==== 22 21211 22 ∆∆∆∆ (4) a briefly, discussions about these losses can illustrate as follows: friction losses friction losses through the barrels of siphon can calculate by using the following formula. g v r l fh f 2 2 2       ××××==== (5) where:       ++++ r b a= f 2 1 (6) where the values of a and b for different materials may be taken as given in table (2). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 182 entrance and exit losses entrance losses can calculate from the following equation (jawad, kanaan,1983) (5) :         ==== 2g v k h 2 1e (7) where: k1: entrance coefficient, which obtained from table (3). exit losses can calculate from the following equation (5) :         ==== 2g v k h 2 2o (8) where: k2: outlet coefficient which taken as 1.0 for most outlets. screen losses losses through screens and trash racks are related the velocity head of the approach flow and the geometry of the rack (spacing, thickness and shape of bars and inclination to the horizontal). screens used at entry and exit on inverted siphons as a safety precaution to prevent children and unauthorized personal from gaining access. the head loss can related to the percentage of waterway area that the bars take up as shown in table (4) below:         ==== 2g v k h 2 ss (9) elbows and bends losses it remains now to consider the effect of elbows and bends, on the discharge of the siphon. the losses in an elbow or a bend in a pipe appear to be due to secondary circulation and to contraction of the flow, which occur, in, and immediately downstream of, the cause of the disturbance. weisbach gives the following formula for the loss of head in elbows (6) .         ==== 2g v fh 2 1e1 (10) where: 2 sin 2.047+ 2 sin 0.9457= f 42 1             θθθθθθθθ (11) according to this theory, if the radius of curvature r does not change, the length ℓb of the bent portion of the pipe, and angle ϑ , have very little effect (if any) on the total loss of head attributable to the bend. the formula was therefore as follows (leliavsky, serrge, 1979) (6) . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 183         ==== 2g v fh 2 2b (12) where:                     90 27 θθθθ / r d 0.16 + 0.13= f2 (13) transitions losses a channel transition may define, as a local change is cross section, which produces a variation in flow from one uniform state to another. in many hydraulic structures the main reason for constricting or fluming the flow at the inlet is to reduce, the costs of construction of the structure and in some cases can provide an expedient device for measurement of discharges in the main body of the structure. it is important that transitions to and from structures is properly designed when head losses are critical. transitions can serve several other functions, namely: 1to minimize canal erosion. 2to increase the seepage path and thereby provide additional safety against piping. 3to retain earth fill at the ends of structures. all transitions may classify as either inlet (contraction) or outlet (expansion) transition. expansion and contraction losses can be finding from the following equations (jawad, kanaan,1983) (5) :         −−−− g vc g v k= h exex 22 22 (for canal structures) (14)         −−−− g vc g v k= h concon 22 22 (for canal structures) (15)         −−−− g vc g v k= h exex 22 21 22 . (for drainage structures) (16)         −−−− g vc g v k= h concon 22 21 22 . (for drainage structures) (17) where: kex & kcon: are the expansion and contraction coefficient respectively, which can obtained from table (5) depending on the discharge values (depending on the reference of [5]). angle of contraction at the upstream is preferred as equal as or less than 27.5 o , and the optimum contraction angle is 14 o , while the angle of the expansion at the downstream is equal or less than 22.5 o (varshney,1972) (10) . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 184 optimization method for designing the inverted siphon the purpose of optimization is to find the best possible solution among the many potential solutions satisfying the chosen criteria. designers often based their designs on the minimum cost as an objective, safety and serviceability. a general mathematical model of the optimization problem can represent in the following form (2) : a certain function (z), called the objective function, n ixf z i ,.........}} 22221,1,1,1,==== ==== (18) which is usually the expected benefit (or the involved cost), involves (n) design variable {x}? such function is to be maximized (or minimized) subject to certain equality or inequality constraints in their general forms: (((( )))) i ib xg iii ,.........22221,1,1,1,==== ==== (19) (((( )))) j ib xq jji ,.........22221,1,1,1,==== ≥≥≥≥ (20) the constraint reflects the design and functional requirements. the vector {x} of the design variables will have optimum values when the objective function reaches its optimum value. objectives functions the objective function (zs) of the present research for steel pipes siphons involves the cost of transportation, cutting, constructions, and filling as (zs = c × d) (raju,1986) (8) , (zs: total cost per unit meter, c: constant, d: diameter of siphon) . . the following equation estimated by (statistica) program with a regression coefficient of (r = 0.996): 0.469596 s d 248791.9 z ××××==== (21) in addition, the objective functions for concrete pipe and box siphons shown below. data for this formula obtained from the reference (7) . 2 cp d177798.44 z ××××==== (22)         ++++==== 33 22 db 514500 z cb (23) the following figure shows the relationships between the costs and the dimensions of concrete siphon (pipe and box) and steel siphons, depending on the previous formulas. constraints for the optimization technique the following constraints that considered for the optimizations technique in this research was as follows: 10.005 ≤ s≤ 0.5 20.6 ≤ v ≤ 3.0 3hf ≥ 0.2 4b ≤ 4.0 5d ≤ 3.0 6d ≤ (y+0.5) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 185 modified hooke and jeeves this method dates back to 1961 (3) but is nonetheless a very efficient and ingenious procedure. the search consists of a sequence of exploration steps about a base point, which if successful followed by pattern moves. the procedure is as follows: a) choose an initial base point b1 and a step length hj for each variable xj, j = 1, 2… n. the program given later uses a fixed step h for each variable, but the modification indicated can be useful. b) carry out an exploration about b1. the purpose of this is to acquire knowledge about the local behavior of the function. this knowledge used to find a likely direction for the pattern move by which it hoped to obtain an even greater reduction in the value of the function. the exploration about b1 proceeds as indicated. i) evaluate ƒ (b1). ii) each variable now changed in turn, by adding the step length. thus ƒ (b1 +h1 e1 ) can be calculated where e1 is a unit vector in the direction of the x1-axis. if this reduces the function, replace b1 by (b1 +h1 e1). if not find ƒ (b1 -h1 e1 ) and replace b1–by (b1 -h1 e1 ) if the function– is reduced. if neither step gives a reduction leave b1 unchanged and consider changes in x2, i.e. find ƒ (b1 +h2 e2 ) etc. when it has considered all n variables, a new base point b2 can obtained. iii) if b2 = b1 i.e. no function reduction has been achieved, the exploration is repeated about the same base point b1 but with a reduced step length. reducing the step length(s) to one tenth of its former value appears to be satisfactory in practice. iv) if b2 ≠ b1 make a pattern move. c) pattern moves utilize the information acquired by exploration, and accomplish the function minimization by moving in the direction of the establish "pattern". the procedure is as follows. i) it seems sensible to move further from the base point b2 in the direction b2 – b1 since that move has already led to a reduction in the function value. therefore, the evaluation of the function at the next pattern point can do. )b-(b 2 b p 1221 ++++==== (24) in general: )b-(b 2 b p i1iii ++++++++==== (25) ii) then continue with exploratory moves about p1 (pi). iii) if the lowest value at step c (ii) is less than the value at the base point b2 (bi+1 in general) then a new base point b3 ( bi+2 ) has been reached. in this case, repeat c (i). otherwise abandon the pattern move from b2 (bi+1) and continue with an exploration about b2 ( bi+1). d) terminate the process when the step length(s) has reduced to a predetermined small value. in this research some modifications on this method has achieved, since this method is not able to move along the constraint and converges on the first point on the constraint that it locates as the solution. with a certain initial point and certain step length, a certain solution has obtained, while with another initial point or another step length another different solution has obtained. these modifications reduce the difference between the two obtained solutions. these modification in this research as follows: 1assume the initial base point within the range of constraints. 2reduce the step length to a lower value such as (0.00001). 3reducing the step length(s) to (1/1.001) of its former value appears to be more satisfactory in practice instead of one tenth at step b (iii). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 186 optimum structural design of inverted siphon the inverted siphon consisting of two horizontal and two vertical slabs built monolithically are ideally suited for a road or a railway bridge crossing with high embankments crossing a stream with a limited flow. the inverted siphon are economical due to their rigidity and monolithic action and seprate foundationa are not required since the bottom slab resting directly on the soil, serves as raft slab. the structural design of a reinforced concrete inveted siphon comprises the detailed analysis of the frame and thrusts due to various types of loading. the computer program was used for an analysis and design of inverted siphon and includes the type of loading that applies on the reinforced concrete inverted siphon, as shown in figure (1). 1.inverted siphon weight the total weight of a reinforced concrete siphon per unit length, wsiph, at a given section with concrete can be calculated from the following simplified equations for approximate total weight of concrete in kn per m and the density of concrete is 24 kn/m 3 , so can be obtained wsiph from the following equation: )( ssiph lhw ××××==== 96 2. fluid loads the weight of fluid per unit length, wf, inside a siphont filled with fluid can be calculated from the following simplified equations for approximate total weight of water in kn per m and the density of water is 10 kn/m 3 , so can be obtained wf from the following equation: 2 10 )( hlw sf −−−−==== 3.earth loads earth load in kn/m is determined by multiplying the weight of the earth prism load above the extremities of the siphon and the density of soil is 18 kn/m 3 , so the earth load on the top slab as follows: es hp γγγγ====1 and the lateral pressure due to the effect of imposed dead load surcharge only, as follows: )( yhkp esss ++++==== γγγγ where ks equal to (1/3) and the pb equal to summation of self weight of siphon and the soil weight and the water weight as follows: )( hlwsiphwfp swb −−−−××××++++++++==== γγγγ so, in this section, the staad pro.2006 sofware program was used to analysis and design the inverted siphon using the above loadings to the reinforcement steel area that required with thickness of slabs (h=(span (ls))/10). in the present study was used the cost of plain concrete is (250000 id/m 3 ) and the cost of reinforced steel is (1200000 id/ton) as shown in table (7). computer program for optimum hydraulic design in this research, the program was writing with "quickbasic" language depending on (modified hook and jeeves) method with some modifications -since (sumt) method cannot be used due to the fractional powers of constrainsto find the optimum hydraulic al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 187 design for the inverted siphon. many examples applied by using this program to check the accuracy of it. the following example solved without the optimization technique and with the optimization technique by using this program. the input data for this program were:(ca, cs, l, ke, k0, ks, cel, kex, …) x(i): initial dimension for siphon (i=1 for pipe siphon, i= loop from 1 to 2, for box and rectangular siphon). h: step length. many examples applied using the program and compared with the design without optimization as follow: the following figure shows a typical section for inverted siphon and so the following table (8) shows the dimensions of siphon with variable discharges, constant velocity (0.82 m/s) and variable elevation for the same canal. the following table (9) shows the dimensions of siphon with variable discharges, variable velocity and constant elevation (1.5 m) for the same canal. the following figure (3) shows the relationship between the cost of siphon construction and discharge. conclusions 1. the modification of the assumed initials base points improved the modified hooke and jeeves method. 2. the modification of the value of step length also improved the modified hooke and jeeves method. 3. in addition, the modifications above, the modification of the value of the reduced step length at each trial improved the modified hooke and jeeves method. 4. a significant construction cost reduced due to optimum hydraulic and structural design for inverted siphon. references 1. aisenbrey, a.j., hayes, r.b., warren, h.j., winsett, d.l. and young, r.b., (1974), "design of small canal structures ", denver, colorado, u.s.a. 2. alhusseini, thulfikar, r.,(2004), " analysis and evaluation of water supply facilities for alhilla city" , m.sc. thesis, college of engineering, babylon university, iraq. 3. bunday, brian d., (1985), "basic optimisation methods ", school of mathematical sciences, university of bradford, london. 4. garg, santosh kumar, (1978), "irrigation engineering and hydraulic structures ", khanna publishers, delhi, india. 5. jawad, kanaan, a., (1983), "design manual irrigation and drainage ", pencol engineering consultants and state organization for land reclamation, baghdad, iraq. 6. leliavsky, serrge, (1979), " irrigation engineering: syphons, weirs and locks ", chapman and hall ltd, london, new delhi, india. 7. ministry of irrigation, state commission for irrigation at babylon governorate, (2004), annual report. 8. raju, n. krishna, (1986), "advanced reinforced concrete design", cbs publishers and distributors, delhi, india. 9. simon, andrew l., korom, scott f. (1997), "hydraulics", prentice hall, u.s.a. 10. varshney, r.s., gupta, s.c., gupta, r.l., (1972), "theory and design of irrigation structures", roorkee university, india. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 188 table (1): silt factor [5]. region f northern 0.7-1.0 central 0.6 southern 0.5 table (2): values of a and b for different materials [4]. materials of the surface of the barrel a b smooth iron pipe 0.00497 0.025 encrusted pipe 0.00996 0.025 smooth cement plaster 0.00316 0.030 ashlars or brick work 0.00401 0.070 rubble masonry or stone pitching 0.00507 0.250 table (3): entrance coefficient [5]. description k1 for square edged inlet flush with vertical walls 0.5 for rounded inlets, radius r where r/ d ≤ 0.15 0.1 for grooved or socket ended pipes 0.15 for projecting concrete pipes 0.2 for projecting steel pipes 0.85 table (4): loss coefficients for screens and trash racks [5]. bar area/waterway area % 5 10 15 20 25 30 loss coefficient (ks) 0.12 0.25 0.42 0.62 0.86 1.15 table (5): expansion and contraction coefficients siphon section discharge m 3 /s kex kcon 2.5-5 0.6 0.3 box > 5 0.2 0.1 < 0.5 1.0 0.5 pipe 0.5-2.5 0.7 0.4 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 189 table(6): data for optimum hydraulic design for inverted siphon q(m3/s) vc(m/s) elev. of water(m) length of siphon(m) kent kext ks kelb case 1 4 0.82 1.50 41.3 0.2 0.3 0.2 0.05 case 2 5 1.0 2.0 50 0.2 0.3 0.2 0.05 case 3 10 1.50 2.0 70 0.2 0.3 0.2 0.05 case 4 20 1.50 2.0 70 0.2 0.3 0.2 0.05 table (7): output of the above input data with and without optimization technique. case no. of sections dimension (m) weight of steel (kg/m) price of siphon (id/m) without optimization 1 1.45 x 1.45 261.812974 531672 1 with optimization 1 1.15 x 1.15 265.105820 456120 without optimization 1 1.54 x 1.54 249.4580 545740 2 with optimization 1 1.29 x 1.29 270.321760 366309 without optimization 1 2.13 x 2.13 255.984728 775776 3 with optimization 1 1.83 x 1.83 244.387199 640956 without optimization 2 2.13 x 2.13 444.715580 1353708 4 with optimization 2 1.83 x 1.83 423.398260 1116555 table (8): dimension of siphon and its number of sections for constant velocity. q(m 3 /s) 4 8 1 0 1 2 1 5 1 8 2 0 2 5 3 0 y(m) v(m/s) 1 .5 3 .0 3 .7 5 4 .5 5 .6 3 6 .7 5 7 .5 9 .3 8 1 1 .3 0 .8 2 1 .1 2 1 .1 2 1 .6 4 1 .6 4 1 .8 2 1 .8 2 2 .0 0 2 .0 0 2 .2 3 2 .2 3 2 .4 5 2 .4 5 2 .5 8 2 .5 8 2 .8 8 2 .8 9 2 .2 3 2 .2 4 s e c ti o n n o . 1 1 1 1 1 1 1 1 2 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 190 he ps ps pb p1 do h ls ls y table (9): dimension of siphon and its number of sections for constant elevation. q(m 3 /s) 4 8 1 0 1 2 1 5 1 8 2 0 2 5 3 0 v(m/s) y(m) 0 .8 2 1 .6 4 2 .0 5 2 .4 6 3 .0 8 3 .6 9 4 .1 0 5 .1 3 6 .1 5 1 .5 0 1 .1 2 1 .1 2 1 .5 8 1 .5 8 1 .7 6 1 .7 7 1 .9 3 1 .9 4 1 .5 8 1 .5 8 1 .7 3 1 .7 3 1 .8 2 1 .8 3 1 .6 6 1 .6 7 1 .8 2 1 .8 3 s e c ti o n n o . 1 1 1 1 2 2 2 3 3 figure (2): relationships between materials cost/ unit meter length and dimensions of inverted siphon. 0.40 0.50 0.60 0.70 0.80 0.90 1.00 dimension of siphon (m) 25000 50000 75000 100000 125000 150000 175000 200000 225000 250000 275000 300000 325000 350000 c o s t (i .d ) cost of concrete pipes cost of concrete box cost of steel pipes figure (1): distribution of earth pressures on inverted siphon. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 191 figure (3): typical section for inverted siphon. figure (4): relationships between cost and discharge of inverted siphon. vc θ main road ∆ hint: length of siphon= l1+l2+l3 4 6 8 10 12 14 16 18 20 22 24 26 28 30 discharge (m3/s) 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 c o s t * 1 0 ^ 7 ( i. d ) with variable velocity and constant elevation with constant velocity and variable elevation article al-qadisiyah journal for engineering sciences 13 (2020) 189–199 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: khalid.ahmed@uomosul.edu.iq (khalid ahmed hussein) https://doi.org/10.30772/qjes.v13i3.660 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. shape grammar strategies for representing the built heritage khalid ahmed hussein a*, emad hani ismaeel a a dept. of architecture, coll. of engineering, university of mosul, iraq a r t i c l e i n f o article history: received 25 june 2020 received in revised form 7 august 2020 accepted 16 august 2020 keywords: shape grammar built heritage historic buildings architectural elements local architecture digitization a b s t r a c t traditional architecture style represents the evolutionary style and experienced characteristics of the urban environment. this style includes a mixture of technical and cognitive values that are difficult to conserve compared to other material resources. one of the important means of conservation is analyzing the deep structures of this architecture and determining their rules and constraints. on the other hand, shape grammar is an effective system for analyzing architecture as it combines mathematical and morphological values in architecture. the current research focuses on the problem of shape grammar strategies for each scope in architecture, in addition to determining the techniques used in the analysis, derivation, and generation of the shapes. it aims for defining the appropriate strategies of shape grammar in each scope in architecture. thus, the significance of this research stems from the disclosure of the potential of shape grammar in analysis, generation, and representation of the built heritage in the same architectural language as a mean of conservation. the research adopts the analysis of studies that employed the shape grammar in the built heritage. the research aim was achieved by determining the strategies of the shape grammar to analyses and represent the built heritage according to its scope. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction historic buildings represent a high-value part of the built heritage and have a prominent role in achieving cultural excellence and local identity el namara et al. [1]. on the other hand, conservation is the action taken to prevent deterioration and conserve cultural and social values in minimal effective action. it embraces all acts that prolong the life of cultural and natural heritage, the object being to present, to those who use and look at historic buildings with wonder, the artistic and human messages that such buildings possess feilden et al. [2]. conservation aims to safeguard cultural heritage while ensuring its accessibility to present and future generations. conservation embraces preventive conservation, remedial conservation, and restoration icom et al.[3]. preventive conservation of cultural heritage includes many activities such as registration, planning, management, besides other aspects, also, in the management, including information management which deals with 3d representation and exchanges the information of the built heritage al-allaf et al. [4]. the traditional architecture represents a cumulative knowledge heritage resulting from construction techniques and local materials in a distinct architectural language; conservation requires defining the knowledge foundations of this architecture. hence, several approaches have been employed to represent the knowledge of this architecture. one of the most prominent of these approaches is the shape grammar that analyses and classifies the architectural elements according to its common characteristic. in architectural theory and practice, the context plays a significant role in proposing architectural principles. contextual structure theory refers to the relationship between new buildings and the current environment during the process of adding new buildings and the restoration of the old buildings to achieve harmony and communication between the past and the present http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 190 khalid ahmed hussein, emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 lambe et al. [5]. thus, the shape grammar is an essential approach to achieve contextuality inbuilt heritage by generating new designs based on the existing architectural style without restricting the designer. 2. shape grammar shape grammar is a production system that generates 2d and 3d shapes based on a set of specific rules, invented by stiny and gips in 1972 as a production system that defines the rules of a set of designs stiny et al. [6]. shape grammar has achieved great importance in architecture since the introduction of its concept. its cognitive importance is embodied in the analysis of the architectural structures and its reproduction in the same language angelo et al. [7]. shape grammar is similar to grammar rules, it is used in architecture as a tool for classification, analyzing, generation, and evaluation the productions in terms of morphological, functional, and mathematical characteristics of the same architecture, in addition to being a tool for creating new designs stiny et al. [6]. these grammars can also evaluate the results and their participation in the same morphological, functional and special characteristics. however, it does not seek to reproduce the architectural language in all its detail, but rather describes it in its essence, and aims of forming other designs in the same architectural language [8]. the worth of shape grammar in analyzing architecture structure is attributed to its ability to combine morphological and mathematical analysis as an algorithm for analyzing the architectural structure of angelo et al. [7]. this feature enabled the shape grammar to analyse the existing architecture in general and traditional in particular, to determine its characteristics to restore the virtual reconstruction of the architecture without changing its language. accordingly, many international experiences studies and researches have employed the shape grammar in conservation and representation of heritage by several methodologies such as computer applications and programming languages. 3. recent literatures for employing the shape grammar in architecture, there are many levels according to the purpose, classification mechanisms, and methodologies to formulate the results. this research highlights these aspects, focusing on employing this technique in analyzing the structure of architecture according to certain criteria. many researches have discussed the issue of heritage components classification, including: abulnour et al. [9]: the research discussed the classification of monuments according to the degree of importance in heritage, the level of deterioration, and the state of preservation. orenia et al. [10]: the study deals with the heritage elements classification in the database, with a hierarchical structure that begins with general elements, decorations, and details, according to the type of elements, characteristics, timelines, and analysis of the elements suitability for reuse. lagomarsino [11]: the study presented a topological classification related to damage of heritage elements in a historical building according to the degree of damages. saleeb et al. [12]: the study discussed the development of a system of classification of heritage elements by comparing the current systems this study aims to present a new concept to analyze the structure of the architectural heritage using shape grammar according to several aspects including the scope of architecture, methodology, and morphological, functional, spatial, mathematical, and typological characteristics. 4. hypothesis and objectives of the research the critical review of previous studies showed that shape grammar is applied in the architectural built heritage within different strategies according to the type of shape grammar, characteristics, techniques for deriving rules, and methods of generating shapes, and there is no study on classifying the strategies of shape grammar used in built heritage. hence, the research problem deals with the absence of a study about strategies of applying shape grammar in different scopes in the built heritage. the research suggests that there are certain strategies for applying shape grammar in each scope of heritage architecture. 5. research methodology the methodology of research adopts analyzing different studies that dealt with applying shape grammar in a different scope of urban heritage. figure 1. research methodology 5.1. the concepts of shape grammar  types of shape grammar al-jameel et al. [13]: standard shape grammar: this grammar depends on applying the rules to initial shape. parametric shape grammar: this grammar applies parameters in rules to syntax new ones.  the characteristics morphological characteristics: dealing with the external morphological properties mathematical characteristics: adopting mathematical analysis to determine the proportions. functional characteristics: determining the restriction on the functional spaces. typological characteristics: determining the relationships between the elements. spatial characteristics: determining the location of an element in a system or a group. khalid ahmed hussein , emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 191  the purpose of employing shape grammar classification: grouping the elements or styles that share the same characteristics. analysing: determining the morphological and mathematical characteristics of a particular style. evaluation: determining the context of a particular element in an architectural language. generation: creating many alternatives in the same architectural language.  the analysing methodology traditional (manual): representing the characteristics and rules in a drawing process. software (computer applications): using applications in analysing digitally. digital languages owl, gdl, city gml, python: representing characteristics  the strategy of formulating the shape grammar benrós et al. [14] topbottom strategy: defining external borders then adding or dividing the elements. bottom -top strategy: defining a central element then adding other elements relationally. addition strategy: adding elements gradually according to priority to reach the final form. division strategy: dividing the total element into other elements to reach the final form. procedural strategy: modelling controlled by shape grammar in computer applications.  the technique of applying the shape grammar city engine: a 3d modelling application for urban scale and façade. sgi: digital applications, based on shape grammar, for generation an architectural style. coordination: the reference point coordinates for generating designs in a traditional method. grid: a grid-based on a determined unit to apply specific shape grammar. 5.2. scopes of the built heritage in general, architecture or built heritage can be divided into different ranges or scopes according to the level of the item of the study. these scopes have a certain level of information and characteristics, so the built heritage can be classified according to studies scopes to jong et al. [15]:  studies in urban scope  studies in masses scope  studies in plan scope  studies in facades scope  studies in architectural elements scope  studies in architectural sections scope  studies in detail scope the research sample was chosen from previous studies to cover all scopes of the built heritage. the selected studies cover all strategies of shape grammar in dealing with built heritage, which is the last studies was researched in this field to determine the formulating methodologies, techniques, characteristics, and strategies for deriving the grammar. next to selecting the studies sample and determining the concepts of the shape grammar, these studies are analyzed to determine the strategy of each scope in representation of the built heritage. table 1analyzing recent literatures and studies according to the shape grammar concepts s. sc. the study case study analysis 1 u rb a n müller et al. [16] 2018 the traditional roman urban in pompeii classifying the urban components based on gis data. classifying the sectors according to the density, coverage ratio, and function. formulating the distribution grammar of areas and street network. importing façades grammar from the digital library using city engine 2 zhu et al. [17] 2015 3d modelling of urban façade in shanghai collecting data and analysis it by google earth via photography. using the city engine to create a 3d model of the building. using the facade rule in city engine to create the automatic grammar cga. 3 di angelo et al. [18] 2012 the traditional bali residences formulating grammar from urban level to the building blocks distributions by determining the direction, intensity, organization, and function. arranging the wings of the house according to the space hierarchy. other details of the decoration that include stones, pillars, roof elements, etc. 4 m a ss e s sass et al. [19] 2007 the prototype in 3d printing classifying elements into walls, columns, windows, ceiling, frieze, additions, stairs, doors, details, then symbolizing them. formulating shape grammar to determine the o components placement in two types, morphological for the element and relational between them. 5 trescak et al. [20] 2012 the traditional church in danube the research applies two types of algorithms, the first is the tree search algorithms and the second is the optimal detection algorithm for the style. the research provides an sgi tool for an automatic creation of designs. 6 tepavčević et al. [21] 2013 a group of heritage churches in france statistical analysing of the morphological characteristics by the multiple comparison method. representing the characteristics according to dimensions, relationships, and categories classifying of grammars into: morphological and typological grammar. apply cga grammar in procedural methodology using city engine. 7 şener et al. [22] 2008 the ottoman mosques classifying the mosque into the structural system, functional and connecting components. determining the central dome which restrict relations with the other element. mathematical analysis to determine proportional systems. determining the hierarchy of components to avoid clashes. 192 khalid ahmed hussein, emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 8 colucci et al. [23] 2020 lorenzo church in norcia (italy) classifying the heritage elements according to the morphological and spatial characteristics. relational and conceptual analysis of the elements using gis modelling the element with city gml language 9 p la n çağdaş et al. [24] 1996 the traditional turkish houses determining the main spaces that include: rooms, stairs, and halls. classifying the dwellings according to the three components relationship. classifying the plan according to morphology to l, o, =, -, + , i, h, u. typological analysis: the corner, the partial, and the integral relationships. 10 stiny et al. [6] 1978 palladian villas style determining the grid and the axis to define the units in specific dimensions. determining of the outer wall that is restricted by the grid. planning the spaces that depend on the grid in a rectangular or t or + shape. determining the main entrances: by its relationship with the axes and halls. determining the column locations in the facade. locating the openings that include windows and doors. 11 ahmed et al. [9] 2004 group of caravansaries in central asia classifying the components according to the morphological characteristics and spatial elements. classifying the plan into: the simple, the multi-cell, and the complex plan. typological analysis of the spatial elements to determine its relationships. defining the spatial constraints to limit irrational applications. formulating the grammar: the boundaries, the cell, the fort, and the entrance 12 eilouti et al. [25] 2012 the traditional damascene house classifying the elements according to the functional, morphological and typological analysis. organizing the plans according to the functional, and spatial characteristics. mathematical analysing of the plan by parameters. formulating the shape grammar from the bottom to top. evaluating the grammars to derive new plans in the same traditional style. 13 abdul raheem et al. [26] 2016 the traditional suakin housing classifying the elements according to functional and spatial characteristics. representing the initial shape in the coordinate x, y. determining the parameters to modify and derive new forms. formulating the functional, spatial, and mathematical grammar. 14 andaroodia et al. [27] 2006 the caravansary in iran classifying the building style according to the determined characteristics. analysing the morphological characteristic of the plans: orientation, axis, entrance, and spatial organization of the components. verification process includes: the courtyard, the iwan, the entrance, rooms adjacent to the courtyard, the room behind the iwan, and the towers. formulating the shape grammars. 15 eilouti et al. [28] 2007 the education buildings in mamluk architecture determining the morphological characteristics: symmetry, proportionality, axes, and transformation. classifying the main components according to the functional analysis. analysing the structure of the plan to determine spatial relationships. formulating the grammar. 16 colakoglu et al. [92] 2000 the traditional housing -hayat style classifying the housing according to morphological, functional, and mathematical characteristics. generating new designs by euclidean transformation, parameters. determine the spatial relationships between the main elements. formulating the grammar that represent the styles of housing: a, b, and c appling the grammar in five stages. 17 chiou et al. [30] 1996 the traditional taiwanese houses determining the mathematical systems in ancient chinese architecture. classifying the temples into: basic, longitudinal, central, and complex types. determining the proportional relationships between the components. determining the origin point 0, 0, by the label (∗), add the central room. 18 benros et al. [14] 2018 palladian villa, malagueira houses, and prairie housing comparing the three shape grammar methodologies to form an effective methodology by the following operations: addition union subtraction. formulating the grammar of palladian villa by top to bottom strategy. formulating the grammar of malagueira by top to bottom strategy. formulating the shape grammar of prairie housing by bottom to top strategy. apply the new methodology to produce a new design. 19 al-jameel et al. [13] 2014 a sample of islamic mosques classifying the common elements into the outer borders, the chapel, the courtyard, the secondary spaces (arcades), and spatial elements. analysing the geometric and morphological characteristics, then make a topological analysis. formulating the grammar by this strategy: top-down, addition, and division. 20 f a c a d e s kitsakis et al. [31] 2017 the traditional greek housing in zagori classifying the element according to morphological and mathematical. determining the level of detail lod to: lod1, lod2, and lod3. formulating the grammar by this strategy: top-down 21 calogero et al.[32] 2013 the eastern wing of the louvre. collecting and representing the data using the basic polygons. analysing the morphological characteristics of the museum facade. applying the grammar using city engine after creating it in obj format. khalid ahmed hussein , emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 193 exporting object models to build and display the new facade. 22 de godo et al.i [33] 2006 the façade of historical areas in brazil determining the facades, followed by a metric and morphological analysis. classifying the facade element according to the analyses. setting the elements inclusion priorities. formulating the grammar from top to bottom, by inserting the initial shape 23 lambe et al. [5] 2017 the traditional pol residences in ahmedabad analysing the plans to classify them to the spatial and functional spaces. determining the priority of applying the grammar: the central space courtyard, then the living space, balcony, kitchen, iwan, porch columns, arches, upper floors, and roof. 24 ria et al. [34] 2016 a group of virtual models classifying the houses according to originality, composition, and morphological characteristics. determining the primary and secondary components. applying the grammar with modifying the transformations such as repetition by the delphi program. 25 e le m e n ts coutinho et al. [35] 2013 the architectural elements in the florence region dividing the column into the components: base, body, crown, and details. classifying columns into: tuscan, doric, ionic, corinthian, and composite. formulating the shape grammar of components, applying the grammar in the city engine. 26 al-kazzaz et al. [36] 2011 a group of islamic minarets determining the components of the element from bottom to top. formulating the original grammar, then the sub-grammar. mathematical analysis by determining the by the parameters. applying and testing hybrid designs in the standards of innovation. 27 d'oliveira et al. [37] 2012 a group of heritage columns determining the shape grammar for classified elements. create an identifying structure for shapes by parameters. mathematical analysis of elements to elicit mathematical equations. applying the grammar and evaluating the results. 28 marzouk et al. [38] 2018 heritage building in egypt developing the concepts of classifying elements according to the style. creating a methodology for the functional, and structural characteristics. classifying elements into structural elements, associated with structure and stand-alone 29 ismaeel et al. [39] 2014 the residential entrance in the mosul classifying the design characteristics into primary, and secondary. classifying elements into: doorstep, column bases, column body, column crown, entrance lintel or arch, engraving over lintel, frieze or cornice. classifying the entrance according to morphological characteristics and the components into: primary entrances, and composite entrances. 30 garavaglia et al. [40] 2020 cuccagna farmhouse in milan classifying the heritage elements according to their morphological and functional characteristics. analysing the heritage elements according to their relational characteristic. scanning with laser then modelling within bim. 31 s e c ti o n s said et al. [41] 2008 the traditional malay housing tm organizing the styles in hierarchy way from the simplest to the complex. determining the central unit in these dwellings and the spaces attached to it. classifying the elements according to the functional analysis. classifying the style according to the space’s relationships 32 chiou et al. [42] 1995 a group of heritage elements in chinese architecture determining the initial shape, which is symbolized by a label. determining the composition of the room, by grammar. adding doors and windows to the central room by its parameters h, w, u. compositing the main building plan, which includes 7 grammars. determine the ceiling according to the shape of the roof, the number of layers 33 d e ta il sayed et al. [43] 2015 islamic motifs selecting the initial shape represented by polygons, then applying the transformation by the parameter that controls the position and transformation operation. the shape grammar was formulated in maya program using python 34 yavuz et al. [44] 2016 the brick patterns in anatolia facades classifying the facades that use bricks according to the shape, dimensions, transformation ratios, and the characteristics of the brick units. determining the basic parameters. classifying the patterns of arrangement of brick units: horizontal piling / plain facing, horizontal-vertical piling / v-wave facing, and oblique piling / spica facing. applying the grammars to produce new patterns. 194 khalid ahmed hussein, emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 next to determining the concepts of the shape grammar that includes the methodology, technique, and strategy for each scope of architecture, the studies are analyzed according to the concept of the shape grammar and the built heritage scopes as shown in table 2. table 2analyzing the studies according to the concept of the shape grammar and the built heritage scopes title type scope characteristic purpose methods strategies technology s e q u e n c e s tu d ie s a n d r e se a rc h p a ra m e tr ic s ta n d a rd d e ta il s s e c ti o n e le m e n ts f a c a d e p la n e s m a ss u rb a n f u n c ti o n a l t y p o lo g y s p a ti a l m o rp h o lo g ic a l m a th e m a ti c a l g e n e ra ti o n e v a lu a ti o n a n a ly si s c la ss if ic a ti o n p ro . l a n g u a g e p ro g ra m m a n u a l p ro c e d u ra l a d d it io n d iv is io n b o tt o m t o p t o p b o tt o m c it y e n g in e s g i c o o rd in a te g ri d 1 kitsakis ● ● ● ● ● ● ● ● ● ● ● 9 çağdaş ● ● ● ● ● ● ● ● ● ● ● 3 stiny ● ● ● ● ● ● ● ● ● 4 coutinho ● ● ● ● ● ● ● ● ● ● ● ● 5 ahmed ● ● ● ● ● ● ● ● ● ● ● ● 6 calogero ● ● ● ● ● ● ● ● ● ● ● ● ● 7 andaroodi ● ● ● ● ● ● ● ● ● ● ● 8 sass ● ● ● ● ● ● ● ● ● ● ● 9 de godoi ● ● ● ● ● ● ● ● ● ● ● ● ● 10 lambe ● ● ● ● ● ● ● ● ● ● ● 11 said ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 12 müller ● ● ● ● ● ● ● ● ● ● ● ● ● 13 al-kazzaz ● ● ● ● ● ● ● ● ● ● 14 trescak ● ● ● ● ● ● ● ● ● ● ● ● 15 yavuz ● ● ● ● ● ● ● ● ● ● 16 d'oliveira ● ● ● ● ● ● ● ● ● ● ● 17 eilouti ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 18 ria ● ● ● ● ● ● ● ● ● ● 12 abdul. ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 92 krishna ● ● ● ● ● ● ● ● ● ● ● ● 91 tepavčevi ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 99 sayed ● ● ● ● ● ● ● ● ● ● ● 93 eilouti ● ● ● ● ● ● ● ● ● ● ● ● 94 marzouk ● ● ● ● ● ● ● ● ● ● 95 colakoglu ● ● ● ● ● ● ● ● ● ● ● ● ● 96 chiou ● ● ● ● ● ● ● ● ● ● ● ● ● ● 97 benros ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 92 al-jameel ● ● ● ● ● ● ● ● ● ● ● ● 92 şener ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 32 ismaeel ● ● ● ● ● ● ● 31 zhu ● ● ● ● ● ● ● ● ● ● ● ● ● ● 39 di angelo ● ● ● ● ● ● ● ● ● ● ● ● ● 33 garavaglia ● ● ● ● ● ● ● 34 colucci ● ● ● ● ● ● ● ● percentage https://www.igi-global.com/dictionary/parametric-modelling/48759 https://en.wikipedia.org/wiki/non-uniform_rational_b-spline https://www.igi-global.com/dictionary/procedural-modelling/48760 https://www.igi-global.com/dictionary/procedural-modelling/48760 https://en.wikipedia.org/wiki/solid_geometry https://ieeexplore.ieee.org/abstract/document/6787179/ https://www.igi-global.com/dictionary/citygml/3849 https://www.igi-global.com/dictionary/gis/12192 https://www.thefreedictionary.com/website https://aecmag.com/technology-mainmenu-35/678-mobile-apps-for-bim-professionals https://rubygarage.org/blog/difference-between-ar-vr-mr https://www.graphisoft.com/archicad/ khalid ahmed hussein , emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 195 table 3-the correlation results of architecture scope with the techniques and strategies, purpose, types, and characteristic of shape grammar type characteristic purpose methods strategies technology p a r a m e tr ic s ta n d a r d f u n c ti o n a l t y p o lo g y s p a ti a l m o r p h o lo g ic a l m a th e m a ti c a l g e n e r a ti o n e v a lu a ti o n a n a ly si s c la ss if ic a ti o n p r o . l a n g u a g e p r o g r a m m a n u a l p r o c e d u r a l b o tt o m t o p t o p b o tt o m d iv is io n a d d it io n c it y e n g in e s g i c o o r d in a te g r id urban 0 22 0 25 66 99 0 99 0 50 75 0 99 0 75 75 25 0 75 50 0 0 0 mass 20 22 10 50 70 99 20 99 30 20 70 20 99 0 50 90 10 0 90 60 30 0 0 planes 73 99 80 60 93 50 40 86 20 53 80 13 13 87 0 47 53 27 87 0 6 46 20 facade 50 99 13 37 75 99 25 87 37 37 75 25 75 25 50 87 13 0 99 50 13 0 13 element 63 99 0 27 45 99 45 73 36 55 90 18 45 55 18 91 9 0 99 27 9 0 9 section 99 99 99 33 99 0 66 99 33 66 99 33 33 66 33 99 0 0 99 0 33 33 0 details 50 99 0 25 25 99 75 75 0 50 75 25 75 25 0 75 25 0 99 0 25 0 0 6. findings by analyzing the previous studies, it is noted that some concepts of shape grammar are related to the type of studies in terms of the architecture scope, the techniques, and strategies used in the analyzing process. the percentage of correlation of the dependent variable (methodology, technique, strategy, purpose, type, and characteristics) with the independent variable (the scope of the study) were calculated to determine the most suitable approach for each scope. a below graphical analysis for the correlation of the independent variable with the variable of shape grammar is given below. figure 1 – analysis of the variables of type in the studies figure 2 analysis of the variables of purpose in the studies figure 3analysis of the variables of strategies in the studies 0 20 40 60 80 100 standard parametric type urban mass planes façade element section details 0 20 40 60 80 100 classification analysis evaluation generation purpose urban mass planes façade element section details 0 20 40 60 80 100 addition division topbottom bottom -top strategies urban mass planes façade element section details https://www.igi-global.com/dictionary/parametric-modelling/48759 https://www.igi-global.com/dictionary/citygml/3849 https://www.igi-global.com/dictionary/gis/12192 https://www.thefreedictionary.com/website https://aecmag.com/technology-mainmenu-35/678-mobile-apps-for-bim-professionals https://rubygarage.org/blog/difference-between-ar-vr-mr https://www.graphisoft.com/archicad/ https://ieeexplore.ieee.org/abstract/document/6787179/ https://en.wikipedia.org/wiki/solid_geometry https://www.igi-global.com/dictionary/procedural-modelling/48760 https://www.igi-global.com/dictionary/procedural-modelling/48760 https://en.wikipedia.org/wiki/non-uniform_rational_b-spline 196 khalid ahmed hussein, emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 figure 4 analysis of the variables of characteristics in the studies figure 5 analysis of the variables of methods in the studies figure 6 analysis of the variables of technology in the studies 7. discussion the results the results show the correlation of the scope of the built heritage with the strategies of shape grammar in the cases studied and analysed as follows: 7.1. general results  in general, although some of the results of the strategies are known in advance, the analytical approach adopted by the research has added more objectivity to the already existing knowledge. besides, these results and the adopted methodology are necessary for the transition to the level of investing in the existing strategies.  the results showed that the strategy of shape grammar varies according to the scope of the built heritage, due to the variation of information level and purpose of the shape grammar, but within the same scope. the results showed the conspicuous similarity of the strategy in dealing with the characteristics of built heritage, and this indicates the presence of specific strategies of shape grammar in each scope. this is what the research assumed in its hypothesis.  in the parametric shape grammar, the parameters showed the possibility of creating the shapes according to the heritage context and its architectural structure, but in the standard shape grammar, the generation process is according to the applying of rules without mathematical analysis.  the type of characteristics is related to the scope of the built heritage. this type of grammar determines the outward appearance of the element and studies the genotype according to its basic components. these characteristics are related to the standard shape grammar. mathematical characteristics determine the placement of the element within the structure, proportions, and its dimensions. these characteristics are related to the parametric shape grammar, and these parameters restrict the mathematical characteristics of the element. relational (spatial) characteristics analyze the relationship of an element to the other within the system. as for the functional characteristics, they are specific to the plans, which study the placement of the spaces to formulate the restrictions as a rule.  the purpose of applying the shape grammar in the built heritage varies and it includes the analysis to determine the hidden structure of the traditional architecture; the classification to identify main categories of heritage elements with common characteristics for the documentation or creating libraries for these elements; the generation to produce new shape belonging to the same local architectural language; and, the evaluation to determine the belonging of the generated shape to the same architectural language.  in the large scope of the built heritage, digital applications were employed to represent the built heritage because of the various restrictions of the shape grammar in this scope, these applications focused on automatic generation processes based on procedural modeling restricted by the rules.  regarding architectural details (such as motifs or ornamentations), shape grammar is used to produce new creative forms that belong to the built heritage language. shape grammar is often converted into programmatic restrictions within a specific application of these details to produce new patterns with the same rules. 0 20 40 60 80 100 mathe morph spatial typo function characteristic urban mass planes façade element section details 0 20 40 60 80 100 manual program pro. language methods urban mass planes façade element section details 0 10 20 30 40 50 60 70 grid coordinate sgi city engine technology urban mass planes façade element section details khalid ahmed hussein , emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199 197 7.2. results of the shape grammar strategies 7.2.1. urban scope:  type of the shape grammar: these studies relied on applying the standard grammar that depends on the rules which include transformation operations on the initial shapes, and no type of parametric grammar applied in these studies.  the characteristics: studies in this type focused on the morphological and structural characteristics of urban and in a lesser on spatial components and their distribution, without using the functional, mathematical, and relational characteristics.  the purpose: most studies, in the urban scope, focused on structural analysis to generate parts of the urban district in the same architectural language, in addition to categorizing urban components.  the purpose: most studies, in the urban scope, focused on structural analysis to generate parts of the urban district in the same architectural language, in addition to categorizing urban components.  the methodology: urban studies used programs and applications.  the strategy: most studies relied on the procedural strategy in generating parts of the urban district, while others relied on a bottomtop strategy by determining the placement of the components.  the technology: most studies used the city engine program. 7.2.2. mass scope  type of shape grammar: these studies used parametric and standard grammar to produce different shapes in the same style.  the characteristics: these studies analyse the morphological, relational, spatial characteristics to study the relational rule, some studies analyzed dimensions to determine the masses proportions.  the purpose: aims to classification and generation  the methodology: this approach has relied on programs.  the strategy: the first is procedural for the generation process, and the second is the bottom-top to assemble the components.  the technology: using the city engine app in the procedural method. 7.2.3. plan scope  type of shape grammar: standard shape grammar was applied in all studies, while parametric grammar was applied to generate an anew plan in the same language.  the characteristics: these studies are based on functional and spatial elements, in addition, other studies are based on the mathematical characteristics by parameters to study the properties of the plan.  the purpose: these studies seek to generate and classify plans according to the characteristic’s analysis.  the methodology: most of these studies relied on manual analysis drawing, while some used program languages to convert them into applications to classify them digitally.  the strategy: the plans adopted two types strategies, the first is topbottom which determines the overall shape and external borders, and the second is bottom -top, which determines the position of a central element or space then the adding other spaces that surround it.  the technology: in formulating the grammar, the x, y coordinates are used to distribute the spaces by the grid or addition strategy. 7.2.4. facade scope  type of shape grammar: in this scope, the standard shape grammar is used by applying rules on the shapes, and the parametric by parameters to generate the facades.  the characteristics: these studies analyzed the morphological characteristics of the facade in addition to the spatial properties and relational analysis to study the positions of elements in the facade.  the purpose: these studies are directed towards generating facades in the same language, and classifying them according to the characteristics.  the methodology: the representation of grammar was done by programming language, while other studies adopted the manual method derivation of grammar.  the strategy: the addition strategy was adopted, in which the elements are added according to its relationships, in two ways, the first is the bottom-top by adding a central element, then adding the other, and the second is top -bottom which determines the external borders of the facade then adding the element gradually.  the technology: most studies have used city engine, while others presented applications for generating after formulating the grammar. 7.2.5. element scope  type of shape grammar: this study used standard grammar, by analyzing the elements morphologically then grouping them. some studies used parametric grammar to generate new elements =.  the characteristics: relying on analyzing the morphological characteristics mainly, then the mathematical characteristics to analyse the proportions, then relational analysis to determine the relationships between the element’s component.  the purpose: these studies mainly aim to classify the architectural elements, then generating them and employing the grammar to evaluate the generation process.  the methodology: the studies rely on manual analysis to formulate the grammar; some applications and programs were employed for that by representing the grammar digitally such as gdl \ owl and others.  strategy: the studies used bottom-top derivation strategy, by adding parts of the elements gradually according to the grammar.  the technology: the city engine program has been applied in several studies for the generation of architectural elements. 7.2.6. section scope  type of shape grammar: these studies are based on parametric and standard grammar in the process of generation and analysis.  the characteristics: they include the analysis of functional and spatial characteristics, in addition to the dimension values to determine the proportions of spaces.  the purpose: the studies aim to classify and generate designs.  the methodology: the grammar in these studies was formulated manually, and other studies used programs in the formulating process.  the strategy: all studies depend on a bottomtop strategy by addition.  the technology: relying on the coordinates to generate the sections of spaces because it is easy to deal with mathematical analysis. 7.2.7. details scope  type of shape grammar: this scope used standard and parametric grammar in formulating shape grammar.  the characteristics: it depends mainly on morphological and mathematical characteristics.  the purpose: these studies aim to generate designs.  the methodology: it depends on generation software.  the strategy: it depends on the bottom-top strategy by addition. 198 khalid ahmed hussein, emad hani ismaeel /al-qadisiyah journal for engineering sciences 13 (2020) 189–199  the technology: some studies have employed a program. 8. conclusions the current research deals with strategies of applying the shape grammar in protecting the built heritage due to its cognitive value, which is complicated to conserve because of the difficulty of the representation of its deep architectural structure that requires analyzing and classifying of its component. the research presents a new approach of shape grammar for dealing with the built heritage due to its advantages in representing mathematically, morphologically, and topologically to formulate its characteristics and restrictions in a shape grammar form which are easy to deal with it in generating designs in the same architectural language. the concepts of shape grammar in architecture were determined (including the type grammar, characteristics, approach of deriving rules, and techniques to generate the shapes), also the scopes of dealing with built heritage were determined according to the level of information (including urban, masses, plans, facades, sections, elements, and details scope) to set strategies of shape grammar in dealing with heritage. the research highlights seven strategies, each of it represents a certain level of information, the first strategy is for the urban level in which the urban fabric is analyzed according to the morphological and typological characteristics of the fabric components, the second related to the building masses to formulate the relational grammar between the main components of the building , the third is the plan strategy which analysis the spaces in a plan mathematically and morphologically according to their functional characteristics to formulate the rules of placing the spaces, the forth is the facade strategy for generating facades in the same architectural language of the urban cultural context ,the fifth is the architectural sections which generate the spaces in building according to the mathematical analysis of section , the sixth is the element strategy to classify the heritage element and determine the genotype according to the morphological analysis, and the seven related to the architectural detail which determines the restriction as rules in shape grammar. these strategies are an important tool for designers to design in the same local architectural language, so it is one of the effective approaches to conserve the built heritage. the importance of research is embodied in presenting specific strategies of shape grammar in representing the built heritage from the urban scope to the small details. these strategies enable the designer to aware of the deep structure of heritage architecture to design in the same architectural language, and this is one of the means of conserving built heritage. 9. recommendations  providing a database for specialists who adopt shape grammar for local architecture, which is a valuable aspect in preserving the built heritage.  digitization the shape grammar in a computerized application to facilitate the deal with it to encourage architects on design in the local architecture style.  adopting the procedural 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[44] a.ö. yavuz, ö. sağıroğlu, reviewing the bricks used in the traditional architecture with the shape grammar method, gazi university journal of science, 29(4) (2016) 741-749. article al-qadisiyah journal for engineering sciences 12 (2019) 193–198 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohammed.abodhaheer@qu.edu.iq (mohammed s. abo dhaheer) https://doi.org/10.30772/qjes.v12i3.617 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. shear behaviour of reinforced self-compacting concrete beams made with treated recycled aggregate doaa h. al-jasimee a and m. s. abo dhaheer b* a ministry of education, al-diwaniyah directorate general of education, al-diwaniyah, iraq. b civil engineering department, university of al-qadisiyah, al-diwaniyah, iraq. a r t i c l e i n f o article history: received 09 september 2019 received in revised form 30 september 2019 accepted 10 october 2019 keywords: treated recycled aggregate polymers shear failure high strength load deflection a b s t r a c t in this paper, an experimental work was conducted to investigate the possibility of improving the structural performance of reinforced self-compacting concrete (scc) beams cast with 100% treated and untreated recycled aggregate (ra). ra was first exposed to a simple treatment method to reduce the amount of its adhered mortar and to improve its performance by the impregnation in polyvinyl alcohol (pva) polymer solution. after completing ra treatments, rectangular simply supported reinforced scc beams cast with ra, treated recycled aggregate (tra) as well as normal aggregate (na), were prepared and tested under two-point loading up to failure. half of the prepared beams were tested to evaluate the shear behaviour of normal strength (ns) scc mixes, while the other half was tested for high strength (hs) scc mixes. the results were evaluated with regards to load deflection response, ultimate failure load, first crack load, and cracking pattern. the main experimental results demonstrated that using treated ra considerably improved the shear capacity of reinforced scc beams in comparison with that of untreated ra. based on the aci 318-14 and euro codes, the shear strength values showed that the treated ra beams were considered more conservative compared to the ra beams in both strength grades. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction the necessity for the utilization of sustainable and recyclable resources in concrete industries is of prime importance in different construction applications. in the field of concrete technology, one of the reasonable and sustainable approach is the use of recycled aggregate (ra) instead of normal aggregate (na). the use of this recyclable materials has positively affected the environment and economic by reducing the consumption of natural resources in the construction industry and reducing the landfill areas. in spite of these positive influences, the majority of the previous studies indicated that the use of ra in concrete construction has negatively influenced its structural performance in terms of shear capacity, deflection, and cracking pattern. the experimental studies conducted in some research work have shown a decrease in the maximum shear strength of the reinforced concrete beams when ra was used [1, 2]. besides, higher deflection values and wider cracks were noticed in the tested beams made of ra. gonzalez and martinez [3] tested 8 reinforced concrete beam specimens with 3% reinforcement ratio and 50 % ra. the test results revealed a marginal increase in the beams deflection values with a slight decrease in their shear capacity when na was replaced by ra. this behaviour was also noticed in other research works [4–6]. moreover, it was found that the general cracking behaviour of the ra concrete beams were somewhat comparable to that of na concrete beams [2, 7–11]. katkhuda and shatarat [12] investigated several concrete beam specimens made of na, ra, and tra and differing in the shear span to depth ratios. ra materials were immersed in hydrochloric acid for 24 hours to minimize their attached old mortar. after hcl treatment process, ras were soaked in sodium metasilicate pentahydrate solution to treat their surface layers http://qu.edu.iq/ mailto:sadjad.amir@qu.edu.iq https://doi.org/10.30772/qjes.v12i3.617 doaa h. al-jasimee and m. s. abo dhaheer /al-qadisiyah journal for engineering sciences 12 (2019) 193–198 194 and to improve their physical properties. the findings showed that when tra was used, a slight improvement in the ultimate shear capacity of concrete beams (with no stirrups reinforcement) compared with that of na and ra beams. the existence of the old cement paste in the natural aggregate playas an essential role in changing the microstructure of ra concrete. this has been reported by many researchers [13–16]. concrete made with ra contains two types of interfacial transition zone (itz), one of them is between the original aggregate and residual mortar, and the other one is between the ra and new cement paste [17]. the presence of these itzs leads to high water absorption, high porosity, and low density and, thus, resulting in less mechanical performance of ra concrete. consequently, the properties of ra need to be improved to attain an appropriate performance before being used in concrete construction. based on the previously published studies about ra, the majority of them have highlighted the structural behaviour of reinforced normal vibrated concrete (nvc) instead of self-compacting concrete (scc). in this paper, the aim was to experimentally assess the possibility of enhancing the structural performance of self-compacting concrete mixes made with 100% ra. different rectangular shaped beams, made with untreated ra, treated ra (tra) as well as na, were prepared and tested in order to investigate their shear behaviour in terms of load versus deflection response, shear cracking and ultimate load, and cracking pattern. a comparison between the experimental test results of this study and those calculated according to aci-code and euro-code are also performed in this study. 2. experimental program 2.1. materials type i portland cement was used in this investigation. coarse aggregate (20 mm maximum size) of three different types were used. they were natural aggregate (na), recycled aggregate (ra), and treated recycled aggregate (tra). crushed old concrete cubes specimens were the source of the used ra. to prepare scc mixes, fine aggregate of 4.75 mm size, limestone powder (lp) as well as viscocrete-5930 superplasticizer were used. in this experimental work, polyvinyl alcohol (pva) polymer solution was used for treatment of ra. the treatment process involved two-stage method, they were (1) minimizing the adhered weak mortar from ra surfaces, and (2) soaking it in polyvinyl alcohol (pva) polymer solution. to minimize the adhered mortar, ra was subjected to washing process into a concrete mixer until loose particles were removed with the discharged water. after that, the prepared ra was soaked in pva solution for 24 hours and left to air-dry in the laboratory environment in order to be used in scc mixes. 2.2. concrete specimens casting and testing relatively normal (ns) and high strength (hs) self-compacting concrete (scc) mixes, with target compressive of 30 and 50 mpa, were respectively prepared. different types of coarse aggregates (natural, recycled, and treated recycled aggregates) were used in these mixes. the prepared scc mixes were designed according to the mix proportioning method adopted in [18,19]. the adopted mix design method is based on constructed design charts for each mix grade. a volumetric substitution of normal aggregate (na) by 100% ra and 100% tra was performed according to their specific gravity, which are 2.35 and 2.42 for ra and tra, respectively. in each of scc mix grade, the amounts of cement, water, fine aggregate, and limestone powder were kept constant. the amount of ingredients used in ns and hs mixes are shown in table 1. the workability of scc mixes were checked based on bs en 206-9 [20] and efnarc [21]. according to these standard specifications, the produced tra mixes have satisfied the necessary selfcompacting criteria of flow-ability and passing-ability. in this regards, the prepared scc mixes have complied with class 2 slump flow (sf2) that ranges from 650 to 750 mm. to attain this range of flow, the super-plasticiser dosages were altered to 3.5 and 6.0 kg for ns and hs mix grades, respectively. furthermore, the investigated fresh scc mixes showed no sign of segregation, indicated by no blockage occurred during the flow and after it has stopped, and the coarse aggregate homogeneously distributed in the fresh mix. in this study, the hardened properties of the prepared scc mixes (using different aggregate types) were evaluated based on compressive strength test, measured according to bs en 12390-3 [22]. for each mix, the average value of three 100×100×100 mm cube specimens was calculated. the test results demonstrated that the substitution of ra with tra has positively influenced the compressive strength of scc mixes. an increase of about 14.7% and 11.8% in tra concrete compressive strength was registered for ns and hs, respectively, compared with ra concrete mix. table 1: amounts of the materials used in scc mixes, kg/m3 nomenclature hcl hydrochloric acid na normal aggregate hs high compressive strength nvc normal vibrated concrete itz interfacial transition zone ns normal compressive strength kg kilogram pva polyvinyl alcohol kn kilo newton ra recycled concrete aggregate lp limestone powder scc self-compacting concrete lvdt linear variable differential transformer tra treated recycled concrete aggregate m meter vc exp experimental shear load mm millimeter vc theo theoretical shear load mpa mega pascal concrete grade cement water w/c limestone powder fine aggregate coarse aggregate normal strength 350 199 0.57 160 770 830 high strength 492 172 0.35 108 755 852 doaa h. al-jasimee and m. s. abo dhaheer /al-qadisiyah journal for engineering sciences 12 (2019) 193–198 195 2.3. details of the tested reinforced scc beams the experimental work of this study includes testing of six rectangular beams having cross-section dimensions of 250 mm depth, 150 mm width, and 1550 mm clear span length. the specimens were subjected to two-point load test. figure 1 shows the details and steel reinforcement of the specimens. the clear concrete cover of the reinforcement was 25 mm from all sides. the scc beams were divided into two groups (group1 and group 2 as presented in table 2). group 1 was prepared for investigating the shear behaviour of normal strength beams, while group 2 was for high strength beams. these beams were reinforced with two ø16 mm steel reinforcing bars provided as a main reinforcement at the bottom, in addition to one ø8 mm bar provided at the top of beam. for a practical reason, two stirrups of ø10 mm bar spaced at 25 mm were placed at the beginning and end of beam out of its clear span. figure 1: details of beam reinforcement table 2: notations of the tested beams figure 2. testing machine and load pattern 2.4. test setup and instrumentations a hydraulic universal testing machine (shown in figure 2) with a capacity of 2000 kn was used to test the beam specimens in this study. the machine was available in the structural laboratory of civil engineering department at al-qadisiyah university. a linear variable differential transformer (lvdt) was used to measure the lateral displacement at the beam mid span. the used lvdt has a maximum bearing capacity of 50 mm. the beam deflection values were recorded when the load was applied on the beam. 3. results and discussion 3.1. load-mid span deflection in this study, the test results of the tested specimens are presented in table 3. they involve the values of compressive strength, first shear cracking load, and ultimate shear load at failure. the behaviour of the six tested beams is shown in figures 3 and 4 with regard to the experimental load against mid-span deflection for ns and hs, respectively. for both strength grades, it can be seen that, at a same shear load value, the deflection of tra-scc beams was less than that of ra-scc beams. the results also showed that the shear cracking load of tra-scc increased approximately 38.9% and 16.7% for ns and hs, respectively, compared with ra-scc beams. figure 3 shows that nans-s beam has the maximum shear load capacity compared with trans-s and rans-s beams. they both exhibited a reduction in shear load capacity of 10.3% and 32.0%, respectively, compared with the reference beam (nans-s). however, beams cast with treated ra (trans-s) demonstrated 32.2% increase in the ultimate shear load compared with that of untreated ra (rans-s) beam, as clearly seen in table 3. this indicates to the effectiveness of the proposed treatment method in enhancing the properties of ra. figure 4 shows the load versus deflection curves for the tested hs beams. the results indicated that the control beam (nahs-s) possessed the maximum shear capacity compared with trahs-s and rahs-s beam. they both demonstrated a reduction of 7.2% and 19.2%, respectively in their shear capacity. however, compared to rahs-s, trahs-s beam exhibited 14.9%, increase in shear capacity (see table 3). this is mainly due to the removal of the weak adhered mortar of ra, as well as to the pva-impregnation that filled the pores and cracks of ra, resulting in enhancing its bond with new cement matrix. apart from its enhancement of concrete structural properties, pva considerably improves mechanical properties of numerous construction materials, such as, concrete [23], gypsum [24], and clay brick [25], due to its ability to change the material microstructure and decrease its pores volume. table 3: test results of the tested scc beams *this is the ratio of the ultimate load of beams relative to the reference beam cast with natural aggregate (0% ra replacement) group number beam notation beams details group 1 nans-s normal aggregatenormal strength rans-s recycled aggregate* normal strength trans-s treated recycled aggregate*normal strength group 2 nahs-s normal aggregate high strength rahs-s recycled aggregate* high strength trahs-s treated recycled aggregate*high strength *the replacement level of na with ra or tra is 100%. beam notation compressive strength (mpa) shear cracking load (kn) ultimate load (kn) load ratio relative to the control* nans-s 32.4 86 97.74 1.00 trans-s 30.5 75 87.72 0.89 rans-s 26.6 54 66.38 0.68 nahs-s 53.4 93 106.41 1.00 trahs-s 51.3 84 98.75 0.93 rahs-s 45.9 72 85.98 0.81 doaa h. al-jasimee and m. s. abo dhaheer /al-qadisiyah journal for engineering sciences 12 (2019) 193–198 196 3.2. crack patterns the crack patterns of beam specimens for ns and hs concrete were presented in figures 5 and 6. at the beam maximum moment (mid-span), the first flexural cracks initiated between two points of applied load. with increasing the load application, new cracks (due to flexural load) started to appear and propagated. after that, flexural shear cracks began to form and becoming inclined toward neutral axis. the flexural shear cracks became wider with increasing the amount of the applied load. then, main diagonal shear cracks appeared, which are the consequences of the beam failure and concrete crushing in the shear region. figures 5 and 6 showed that the shear crack patterns of scc beam specimens made with na, tra, and ra concrete were generally identical in each strength grade. figure 3: load-mid span deflection for beams of group 1 figure 4: load-mid span deflection for beams of group 2 figure 5: the cracks pattern of nans-s (top), trans-s (middle), and rans-s (bottom) beams doaa h. al-jasimee and m. s. abo dhaheer /al-qadisiyah journal for engineering sciences 12 (2019) 193–198 197 figure 6: the cracks pattern of nahs-s (top), trahs-s (middle), and rahs-s (bottom) beams. 3.3. comparison of calculated and experimental shear strength in this study, the ultimate shear strength was found from the experimental test results, whereas the theoretical ultimate strength was determined by aci committee 318 code (2014) [26] using eq. 1, and the euro-code 2-05 [27] using eq. 2. the theoretical shear load (vc theo) from the aci code was calculated for the tested beam specimens by adopting the equation below. 𝑉𝑐 = (0.16√𝑓𝑐 + 17 𝜌 𝑎 𝑑⁄ ) 𝑏𝑑 ≤ 0.29√𝑓𝑐 𝑏𝑑 (1) here: vc: shear strength (theoretical), kn. 𝜌: the longitudinal reinforcement ratio of beam. fc: the concrete compressive strength (mpa). b: width of the section (mm) d: effective depth of beam (mm). a: shear span (mm). the shear force (vc theo) based on euro code 2-05 can be determined by equation below. 𝑉𝑐 = (0.18 𝐾(100 𝜌 𝑓𝑐) 1 3⁄ ) 𝑏𝑑 ≥ (0.035 𝐾 3 2⁄ √𝑓𝑐) 𝑏𝑑 (2) where 𝐾 = (1 + √ 200 𝑑 ) ≤ 2.0 figures 7 and 8 illustrate a comparison based on experimental shear strength relative to aci and euro code (vc exp / vc theo) for normal (ns) and high strength (hs). based on aci code, it is indicated that the shear strength values were conservative for all scc beams, regardless the compressive strength beam grade. based on euro code, the control beams (na-scc) and treated ra beams (tra-scc) were more conservative compared with that of untreated ra beams, for ns, the ratio ranged between 1.3 to 1.64 for reference beam (nans-s), 1.17 to 1.5 for transs beam, and 1.01 to 1.30 for rans-s beam (see figure 7). while for hs, the ratio ranged from 1.2 to 1.41 for control beam, 1.12 to 1.33 for trahss beam, and 1.0 to 1.2 for rahs-s beam (figure 8). it is worth noting that the aci and euro-code underestimated the shear strength for all of the tested beams. however, the ratio seems to decrease with increasing the beam concrete strength. in this regard, it is to be noted that the available standard codes could be used to design the tra and ra concrete beam specimens. figure 7: comparsion of experimental results for beams of group 1. figure 8: comparsion of experimental results for beams of group 2. doaa h. al-jasimee and m. s. abo dhaheer /al-qadisiyah journal for engineering sciences 12 (2019) 193–198 198 4. conclusions in this paper, successful sustainable reinforced scc members have been prepared. the experimental test results showed that the proposed ra treatment method have played an essential role in improving the structural behavior of reinforced scc beams. this primarily due to the removal of the loose old mortar of ra, as well as to the effectiveness of pva polymer to fill the formed pores and cracks of ra, and improve the bond between particles of cement matrix. from the main findings of this study, the following conclusions can be drawn: 1. the ultimate shear load of treated ra self-compacting concrete beams was higher than that of untreated ra beams by 32.2% and 14.9% for normal and high strength, respectively. 2. the shear capacity of the untreated ra-scc beams, cast with hs concrete, dropped approximately 19.2% compared with that of nascc beams. however, shear capacity of the untreated ra beams cast with ns concrete dropped significantly (about 32.0%). 3. the shear cracking load of tra-scc increased approximately 38.9% and 16.7% for ns and hs, respectively, compared with ra-scc beams. 4. the crack patterns of scc beam specimens made with na, tra, and ra concrete were generally identical for each strength grade of the tested beams. 5. based on the international standard codes (aci 318-14 and euro-code), the shear strength values of na-scc and tra-scc beams were more conservative compared with that of ra-scc beams, regardless the compressive strength beam grade. therefore, the available standard codes can be used to design the tra and ra concrete beam specimens. references [1] z. lei-shun, z. xiao-lei, and y. a. n. guo-xin, “experimental research on the shearing capacity of recycled concrete beams without stirrups,” j. zhengzhou univ. 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[27] s. for c. european, “eurocode 2 : design of concrete structures part 1-1 : general rules”, 2005. article al-qadisiyah journal for engineering sciences 14 (2021) 014–020 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: adilnayeeif@gmail.com (adil abed nayeeif) https://doi.org/10.30772/qjes.v14i1.730 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. review on composite – laminated material analysis in matlab using peizo – electric sensor and actuator hayder abdul khaliq alia, adil abed nayeeifa* amechanical engineering department, al-mustansiriyah university, baghdad, iraq. a r t i c l e i n f o article history: received 9 january 2021 received in revised form 3 april 2021 accepted 15 april 2021 keywords: composite – laminated piezo-electric , analysis sensor ,actuators fsdt – hsdt , matlab a b s t r a c t the current review covers numerical analysis using matlab program for multi-layer composite materials. which involves studies are related to the intersection with fibers, between layers and piezoelectric layer or patch. it has been reported that using matlab program has a great flexibility in analysis due to its library which includes various numerical methods. in addition to the ability of programming and developing the finite element technology to calculate the stress and strain in each layer based on different deformation methods such as (fsdt and hsdt), to obtain mechanical properties. it has been claimed that there is a deviation in results between matlab and ansys for the same 20-layer composite material. using matlab in dynamic analysis in various methods such as newmark, rayleigh damping, timoshenko, and eulerbernoulli exhibit good agreement with natural frequencies and mode shapes. moreover, matlab is useful for the real-time process of data acquisition to deliver a digital model of a composite material coated with a piezoelectric plate and is an ideal material for sensing, detecting, and controlling vibration inhibition. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction matlab software is already used to analysis of multilayered composite material and to compute the stress and strain developed in each layer of laminated composite beam reinforced by carbon fiber, as shown in fig. 1. using matlab software to calculate the stiffness of every layer and the stress of every layer under an axial loading at the centroid of the beam shows an excellent agreement with analytical expression [1,2,3]. the normal load effects on layers with various orientations were studied in balcı et al. [4], a code of matlab was expanded to define the analysis for stresses and strains support on classical lamination. in comparison with experimental results a great verification and correction for the stress values was achived in the direction of loading. currently, the combination of lightweight with high or acceptable durability structures become a prime concern of designers because they are widely accepted by controlling the ratio of high stiffness to weight. the role of matlab here is useful for calculating the solution and obtaining design results that are useful in practical applications. in addition to the figure 1the researcher [1] points out in (a) that the analytical solution results in matlab approach the experiment logged data. (b) specimen. flexibility in performing numerical analysis under the effect of parameters with the different support conditions, laminate diagrams, and layered orientations. using matlab for analysis of plate elements with four quadruple nodes and every node has 5 dof, the model of a finite element http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ hayder abdul khaliq ali, adil abed nayeeif /al-qadisiyah journal for engineering sciences 14 (2021) 014–020 15 was coded in matlab formatting as in [5, 6] depending on the 1st degree of shear deformation theory (fsdt). tapered composite beam model analysis was developed in gayen et al. [7] using the matlab software to compute distributions of stress (such as the stresses in the axial direction of the in-plane and the shear stresses between the laminates) in symmetric and asymmetric multi-layer composite beams with circular tapered cross-section obey to hygro-thermal loads and the compositions were validated using solutions available in the literature. the thermal loads are a linear function of the coordinates in the levels of every layer. a stress calculation was developed as shown in fig. 2 based on conventional lamination modification and parallel axis theories. figure 2the researcher in [7] illustrated the behaviour of shear stress distribution of the inter-laminar composite beam. 2. dynamic analysis based on the classical theory of the laminated plate, the three-dimension finite element model is used in conjunction with the integration method (newmark) to find the damping response of the asymmetric composite beam. a matlab code is written in [8, 9], which was developed to implement dynamic analysis (rayleigh damping) for different damping ratios of the responses of the movable load, step, and impulse functions with which researchers tested the composed material of the beam. the dynamic beam response is formulated as a dynamic magnification operator which is got from the static and dynamic displacements in the midpoint. the matlab code is used to process significant factors, for example, displacement and quickness responses of the composite beam for various buckling load with constant velocity, and the directions of the lamina, the impulse unit and step unit reactions of the pined – pinned supports are introduced for different damping proportions and contrasted and dynamic examination of the anisotropic aluminum beam execution. the product code was created by the researcher in lee [10] utilizing the matlab 6.5 programming to locate the 1st and 2nd mode shapes and normal frequencies corresponding to the delamination composite beams. this code incorporates a finite element investigation of free vibration of the clamp free boundaries also with pinned – pinned symmetric beams in various layup arrangements. the free vibration reactions of the laminated beams are considered utilizing the euler-bernoulli beam and classical lamination hypotheses. pc matlab code was created to inspect the impacts of the width and area of the delamination, the layer direction, and the sort of the limit condition on the natural frequency. while in working miranda [11], several application tools were created in matlab programming. which are utilized uncovered key parts of this software and extraordinarily expanded the nature of examination time. which is posted here for thick composite packages. for thin beams, timoshenko and euler-bernoulli-based models are also provided results that are consistent with distributed logical information, and since they expend less calculation time, one can conclude that in these statuses it is not important to utilize more mind-boggling hypotheses. concerning the expectation of dynamic conduct, the higher shear deformation hypothesis gave a few preferences to the next two speculations, particularly for higher-vibration patterns. the work in miranda [11] comprises the improvement of three finite element models dependent on the higher-order shear deformation hypothesis for static and dynamic investigation of laminated beams. fifteen case studies were studied for various loads and support conditions. the software matlab has been approved computing tool, in keeping with its largest academic importance. again, matlab programming was constructed using a rectangular isometric plate element in binh et al. [12] with 5 dof per node depending on the mindlin-plate method to obtain a numerical bending and result and analysis of vibration for the non-reinforced and rigid folded composite laminated plate by using the finite element procedure. a great arrangement was established between the results of this strategy and other distributed results reachable in the writing. the finite element technique was examined utilizing plate elements with eight-nodded isoperimetric, relied on the 1st order shear deformation technique to analyze the transient responses and vibration of the stiffened and un-stiffened folded composite plate covers by considering the various parameters. concerning the expectation of dynamic conduct, the higher shear deformation hypothesis gave a few preferences to the next two speculations, particularly for highervibration patterns. the work in miranda [11] comprises the improvement of three finite element models depending on the higher-order shear deformation hypothesis for static and dynamic investigation of laminated beams. fifteen case studies were studied for various loads and support conditions. the software matlab has been approved computing tool, in keeping with its largest academic importance. again, matlab programming was constructed using a rectangular isometric plate element in binh et al. [12] with 5 dof per node depending on the mindlin-plate method to obtain a numerical bending and result and analysis of vibration for the nonreinforced and rigid folded composite laminated plate by using the finite element procedure. a great arrangement was established between the results of this strategy and other distributed results reachable in the writing. the finite element technique was examined utilizing plate elements with eight-nodded isoperimetric, relied upon the 1st order shear deformation technique to analyze the transient responses and vibration of the stiffened and un-stiffened folded composite plate covers by considering the various parameters. lateral shear deformation, plate rotation inertia, and stiffening techniques are known to be the most advanced in the model presented by researchers. several examples of models in belarbi et al. [13] have been analyzed with the expectation of complimentary vibration examination of laminar and sandwich plates to exhibit the presentation and flexibility of the finite element model created utilizing the matlab code that is utilized to tackle the eigenvalue issue. the results of the numerical solution obtained were compared with past results of exact and finite element solutions. al-tabey [14] was obtained the first six of the mode shapes and natural frequencies of the rectangular composite plate laminated symmetric angle-ply with 16 author, author /al-qadisiyah journal for engineering sciences 14 (2021) 014–020 simply and free boundaries (s-s-f-f) used a transition matrix of a finitestrip technique. the plate thickness is uniform on the x-axis while the thickness varied on the y-axis. it was imposed that the simply supported boundaries in the direction of the thickness that change but at the other direction approximated free. the obtained results using matlab validate the proposed technique for the classical boundary of simply support free end (ssff) at the plate edges. fig. 3 shows the mode shapes for the first two basic frequencies separated in two columns of this figure drawings, the first column shows in surface form the mode shapes and the second one shows the surface plate mode shapes as a contour. figure 3 the first two natural frequencies of the symmetric rectangular laminated plate and mode shapes with variable thickness of the rectangular laminated plate [14]. the plan engineers of laminate composite material under the best stacking sequence and optimum angles of the fiber in every lamina add to the number of layers (lamina) itself dependent on criteria, for example, accomplishing the highest natural frequencies or the biggest load of buckling. the composite materials analysis model is used for estimation of the resultant properties of the material based on classical and numerical theory such as finite element techniques. the method of estimated properties utilized for calculating the dynamic properties of the members comprised of these materials as identical isotropic members. across this level, a graphical user interface tool in jones [15] was created utilizing matlab software to create an easy-to-use environment for computing the properties of total materials, where users can enter the orthotropic properties with the number of layers, and the software computes the bending, expansion, and the matrices of coupling stiffness, besides, gauges the density, in total elastic constants, and poisson proportions. the constants results acquired from matlab programming are approved utilizing the ansys program, in which the stacking of laminar sequence is built and the member is exposed to uniform strain at the end of free support, while the response of stress is normal at the fixed end. the updated interface improves the design process to some reach. the dynamic investigation is shown regarding the fundamental natural frequency and the basic buckling load utilizing these general physical constants as a later aspect of the examination. furthermore, matlab has ideally suited for the formulation of the matrices which is extensively used to represent the mechanical behavior of composite materials. moreover, graphic interfaces provide an efficient way to use as in article barton et al. [16] deals with the topics presented in a us naval academy course in composite mechanics and provides an overview of the matlab code that performs the analysis including topics of deflection analysis, stress, and strain distribution, and stiffness analysis. matlab provides a powerful platform for performing desired matrix calculations and provides an efficient graphical tools interface, employing menu commands, to execute the program. using matlab, m-files are created to perform a specific part of the computation, basic stress analysis, for example, and then they are grouped using menu commands that provide a graphical interface. the article provides an extension of the study conducted by sigmund lee et al. [17] with a 99 line following the optimized command topology written in matlab. the element stiffness matrix for the level stress problem was written with isotropic materials in lines 86-99 was changed to the application of orthotropic and laminated composites. matlab code was given for the matrix, representing the stiffness of the laminated composite and numerical case study examples were provided to show the change from isotropic material to the laminated and orthotropic composite plates to improve the topology. the work in paper ramsaroop et al. [18] manages the production of matlab text records that help the user in planning a composite layer to work in safe conditions. program inputs are material properties, material cutoff points, and stacking conditions. conditions identified with hooke's law for the two-dimensional composites were utilized to process worldwide and neighborhood strains and weights on each layer. the structure disappointment examination was performed through the tsai-wu disappointment hypothesis. the program yields the ideal number of fiber layers which are needed for the composite lamina, just as the direction of every lamina. matlab was used in the optimization theory to find the best design dimensions. the effect of force on hybrid composites was the aim of the study bhingare et al. [19], using the matlab finite element analysis theory. the element used for analysis is eightnodded iso-parametric. at each node, five degrees of freedom are considered that are three displacements and two rotations. the fraction of glass fiber is replaced by carbon fiber to see the effect on strength of the composite plate. symmetric glass/epoxy and glass/carbon/epoxy composite lamina of different orientation angles like (0/0), (45/0), (90/0) are used for analysis purposes and stress values found. for the study, hybrid composites are considered which is made from e-glass, carbon, and epoxy with different orientations to get the stress values of the plate under uniformly distributed transverse load. in other studies, such as [20, 21, 22], the resulting deflection in constructs was calculated using matlab code to solve linear algebraic problems where the solution procedure was implemented using the generalized differential square (gdq) technique in matlab code. the shear stresses and normal stresses subsequently evaluated with the present methodology agree well with the results get from semianalytical and numerical techniques. the terms of the geometric boundaries of the plate are determined by the same agreement presented in the works. finally, matlab function was used to avoid numerical instability inorder to numerically evaluate the elastic geometric stiffness relationships tornabene et al. [23]. 3. smart composite materials in smart composite studies, matlab was used to validate the results obtained with ansys software for the symmetrically laminated composite plates with simply supported which were subject to a uniformly distributed load and following the classical lamination theory. where the validation of the results of the analysis was for the same plate consisting of 20-ply, in addition to this the influence of the stacking sequence on the bending stiffness was revealed in [2426]. it should be noted here that one of the advantages of matlab is also the ease and apparent flexibility of entering the material properties of each layer through the matlab code, as the hayder abdul khaliq ali, adil abed nayeeif /al-qadisiyah journal for engineering sciences 14 (2021) 014–020 17 code is entered for only five physical constants in this research, compared to the program ansys, which requires nine inputs for material properties at the same analysis. by focusing on the researcher publishing adviser et al. [24], it was discovered that a major mistake proportion between the matlab programming and ansys deviation results is identified with the matrices estimations of d16 and d26 don't contain zeros for the layers angles are not 0º or 90º, and in this way, the covering differential equation was changed. however, the researchers in [27, 28] obtained a numerical model of a covered composite beam with piezoelectric lamina, for example, polyvinylidene fluoride (pvdf) which from the outset was found by kawai et al. [29]. because of its special properties, for example, flexibility, durability, workability, and so on, pvdf is a perfect material for sensing, detecting, and damping control of vibration as in fig. 4 of distributed parameters, such as beams, plates, shells … etc. figure 4 a composite beam stacking layers with a piezoelectric lamina for sensing and actuation [28]. the constitutive equations in [28] including the piezoelectric-electric layer concerning the plane of the laminate coordinates are {𝜎}𝑘 = [�̅�]𝑘 {𝜀}𝑘 − [�̅�]𝑘 {𝐸}𝑘 (1) {𝐷}𝑘 = [�̅�]𝑘 {𝜀}𝑘 − [�̅�]𝑘 {𝐸}𝑘 (2) where: {𝜎} , {𝜀} are stresses and strains in vector form, {𝐷}, {𝐸} are conductor vector of the electrical displacement, and electrical field vectors, [�̅�] , [ �̅� ] are the constants of elasticity, and permittivity matrices, respectively, [�̅�], [�̅�]𝑇 are piezoelectric constant and its transpose. the above two equations illustrated the inverse and direct piezoelectric effects, respectively. anisotropic properties of this model that possess the piezoelectric materials as shown in fig. 4. the pvdf is chosen as a sensor material and at the same time actuators [30, 31]. it is possible to design a control system with a variable vibration amplitude of the beam by negative velocity feedback control gain as graphical results, using matlab proved that the feedback control system can be used to suppression the vibration of the laminated beams and appears good control through the temporary response of the laminate beam during examination with using matlab in the study [32, 33]. the damping of epoxy reinforced by carbon fiber of composite beams was measured experimentally by a piezoceramic (sensor and actuator type) and was compared with the theoretical estimation. good agreement of damping ratio, and the basic frequency of the finite element modeling with those of the measured values by the piezoceramics with considering that the adhesive layer has stiffness and damping impact, for example, the concentrated in [34-36]. the characteristic damping coefficient of the model structure is an important performance index to control the vibration of the structure than the damping ratio (ζ). also in baillargeon et al. [37], the piezoelectric embedded as a shear actuators type were used to control or to dissipate the vibration of laminated composite plates. while maximizing the controllability index to specified optimized sitee for the actuator patch of a macro-fiber-composite (mfc) type. the linear quadratic regulator (lqr) approach is used in [38-39], to model the interaction between the mfc and the active substance structure as one of the laminar layers. finally, the software matlab has been analyzing a smart laminated plate based on the inverse hyperbolic shear deformation theory (ihsdt) to create a finite element approach text code in matlab software used to analyze of bending and buckling of a smart composite plate. the approval of as of late created (ihsdt) demonstrated a smart composite structure by the examination in [40-44] and numerical problems indicating the varieties in the buckling behavior of a smart composite plate for different parametric varieties are introduced. additionally, in this study, a numerical example of control on the deflection and buckling load capacity is introduced as an inner defect of stacking layers of composite plates. a comparison study considers portraying the viability of utilizing a piezo patch only at the center rather than piezo-layers are additionally introduced. the above-mentioned applications in this section and the preceding sections demonstrate the commitment of the current work to a useful review that clarifies the importance of the matlab program in analyzing stratified compounds. piezoelectric macro fiber composite (mfc) integration enables energy harvesting, sensing, and operation, with existing applications in space, automotive and renewable energy. there is a gap present in the literature on dynamic response modeling of piezoelectric vibration energy harvesting (pveh) concerning real-world vibration data jia et al. [45]. most of the simulations were either semi-analytic matlab models not specific to geometry, or basic finite element simulations limited to sinusoidal analysis. however, the use of representative environment vibration data is critical to predicting the practical behavior of industrial development. the physics of piezoelectric devices that include solid mechanics and static electricity was combined with the electrical circuit defined in this finite element model. the structure was dynamically simulated using interpolated vibration data files, while the orthotic material properties of the mfc and the carbon fiber composite were individually determined for accuracy lahoti et al. [46]. and singh et al.[47] computed the geometric distortion of the smart jacket plate structure across the green-lagrange strain field including all higherorder nonlinear terms. desired responses are evaluated mathematically using native computer code in the matlab environment with the help of the current top-order model and finite element steps. the nonlinear dynamic deflection values are obtained through the direct iterative method combined with newmark integration. besides, the accuracy of the proposed model is demonstrated by a comparative study with available published literature with and without electric field potentials. 18 author, author /al-qadisiyah journal for engineering sciences 14 (2021) 014–020 in a study rouzegar et al. [48], a finite element formula was developed for forced vibration analysis of viscoelastic flexible composite panels combined with a piezoelectric layer based on the four-variable redundant plate theory (rpt). using rpt of both thick and thin plates with equality of variance of transverse shear stresses across layer thickness, the dynamic behavior of the smart flexible viscoelastic plate was studied. optimal designs are applied to surface pressures, where the substrateactuator composite is robust enough to preserve shape but allows for the desired curvature under excitation. in applications where dynamic pressures are high, this trade-off restricts substrate to actuator thickness ratios. one way to improve actuation authority while maintaining stiffness is to use multiple piezo composite actuators. a review of the potential for new design space for multilayer actuators is presented in wright et al. [49] which explores the benefits and drawbacks of using multilayer piezo composite actuators with a four-point loading condition, the actuators are modeled using the finite element method and are described using wellknown free strain and blocked force conditions. on multilayer piezo composites with different thickness ratios, substrate content, and multiple piezo composite layers, a parametric analysis is carried out in the form of maximum curvature, work is done, by several layers, results for the parametric analysis are provided. smart laminated composite structure (bonded with shape memory alloy; sma) thermal buckling energy, numerically analyzed via a higher-order finite element analysis in combination with marching technique. the excess geometric distortion of the structure was established by green's strain function under the elevated environment, although the material nonlinearity counted with the help of the marching procedure. the process results are values received by calculating the generalized eigenvalue equations via a customized matlab katariya et al. [50]. the comprehensive behavior of the present finite element implementations (least buckling load parameter) is calculated by solving an adequate number of numerical incidents, including the specified input parameter. the current numerical model is further enhanced to evaluate and report in detail the influence on the buckling temperature of different geometry parameters of the sandwich panel, including the sma effect. due to their capacity to show large displacements and create complex structures, autonomous multilayer systems are the subject of recent studies. these devices have been designed with active materials that respond to diverse stimuli, including electrically active and magnetic materials, to perform useful functions and achieve a range of target shapes compared to monophonic/dichromatic structures. however, it is time-consuming and expensive to produce these tools for experimentation, ensuring that simulation is used as a means to build systems with high performance. these systems are optimized to satisfy the specifications of applications like clutch soft robotics. a genetic algorithm developed by matlab for various objective functions induces a multi-objective optimizing problem and the execution of an optimization problem in a case study. in the case study erol et al. [51], optimization outcomes are examined by analyzing the alternative designs of the optimization problem on the pareto interaction. different trade-offs are calculated between the thematic roles, and, depending on application demands and preferences, different feasible designs are considered to be more desirable than others. the research study in keshtkar et al. [52] aims to understand, by developing a theoretical model of the system, the behavior of fiber-reinforced elastomers integrated with shape memory alloy (sma) wires. two distinct models are derived, one to understand the sma wire actuator dynamics and the other to describe the composite bending dynamics. models are then combined to analyze the system behavior fully. in matlab / simulink, numerical simulations of the mathematical model are performed and the simulation results are experimentally validated. to regulate the shape, deflection, and twisting of a system, the model obtained can be used to design control algorithms. 4. conclusion the main conclusions have been drawn from using matlab in modelling laminated composite materials at different paraameters are the following : it is found that creating and developing modelling programs by matlab is not complicated. in specific areas on the smart composite plates, suppress vibrations and control both the bending and twisting of laminates of the composite plate have been done with helping of piezoelectric layers and also in sensing the deflection, bending, and stress. it is observed that the composite materials can be used in advanced applications such as smart composite materials and take advantage of the matlab program as an effective tool in real-time applications. references [1] t. s. alshahbouni, “stress analysis of laminated composite beam by using matlab software,” int. j. sci. res., 2017, doi: 10.21275/art20174775. 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[52] n. keshtkar and k. robenack, “mathematical modeling of fiber-elastomer composites with embedded shape memory alloys,” 2020, doi: 10.1109/icstcc50638.2020.9259736. article al-qadisiyah journal for engineering sciences 14 (2021) 066–074 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: donia.ali@utq.edu.iq (dunya a. mohammad) https://doi.org/10.30772/qjes.v14i1.736 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. numerical investigation of the electric double-layer effect on the performance of microchannel heat exchanger at combined electroosmotic and pressure-driven flow dunya a. mohammada*, mushtaq i. hasana, ahmed j. shkaraha amechanical engineering department, college of engineering, university of thi-qar –iraq. a r t i c l e i n f o article history: received 4 april 2021 received in revised form 8 may 2021 accepted 23 may 2021 keywords: microchannel heat exchanger (mche), electric double layer (edl) thickness, electroosmotic flow, poisson-boltzmann equation. a b s t r a c t numerically investigated the electric double layer (edl) effects on the performance of the square microchannel heat exchanger (mche) at combined electro-osmotic and pressure-driven flow with compared pure pressure-driven with a hydraulic diameter (10 – 50) μm. we defined at any size (dh) of microchannel heat exchanger become the impact of edl very slight with the studied effect of electric double layer thickness λ. the diluted water 1:1 potassium chloride (kcl) solution is used as a working fluid at an ionic concentration (10−4, 10−6) m, silicon microchannel at zeta potential of surface -0.2 volt. a three-dimensional (3d) poisson-boltzmann equations and naiver-stoke equations with applied electric field solved by using the finite volume scheme in this work. the results show an increase in pressure drop of the microchannel heat exchanger at combined flow electroosmotic and pressure-driven flow with a percentage of 31.09 % at an ionic concentration 10−4 m and 42.71 % at 10−6 m, increase in pumping power, especially at low ionic concentration. slight enhancement in average heat transfer rate and effectiveness due to an increase in average temperature difference. decrease in overall performance at combined electroosmotic and pressure-driven flow compared with pure pressure driven. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction in recent decades, rapid progress is observed in the manufacturing of microsystems (have a length between 1 μm – 1 mm) especially in microelectronic mechanic’s system (mems) which integrates mechanical and electrical systems. the development in mems caused an augmentation in understanding the structure and flow of fluid. manufacture of microelectronic mechanic’s system (mems) by using different techniques such as bulk silicon micromachining, surface silicon micromachining, lithography, electro-discharge machining (edm) and plastic modeling … etc. mushtaq i. hasan et al. [1]. basic phenomena of electro-kinetic in the microchannel can be classified into electro-osmosis, electrophoresis, electro-migration, and streaming potential. the process of transporting fluid in a microchannel subjected to an electric field is called electroosmotic flow or pressure gradient is called pressure-driven flow or transport of fluid by an applied electric field and pressure-driven together this called combined electroosmotic and pressure-driven flow berli [2]. a number of studies investigated the effect of edl at pressure-driven or combined electroosmotic and pressure-driven flow. for instance, chun and li (1997) [3] numerically studied the impact of the electrical double layer (edl) on the flow of liquid, pressure distribution, streaming potential, and friction coefficient for rectangular microchannel. 2d poisson-boltzmann equation and the exact solution to the motion equation were solved by recruiting the green function formulation. they found that high zeta potential and law value of ionic concentration lead to a great effect of electric double layer field on the flow of liquid. the increase in http://qu.edu.iq/ mailto:donia.ali@utq.edu.iq https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 67 pressure drop caused increased induced electro-kinetic potential, while the increase in the ionic concentration of solution leads to a decrease in induced electro-kinetic. the edl effect caused an increment in friction coefficient and viscosity apparent compared with no electric double layer effect. prashanta d. and ali b. (2001) [4] conducted an analytical solution of steady newtonian flow through a 2d straight channel with combined pressure-driven flow pdf and electro-osmotic flow eof at constant zeta potential of wall and constant buffer concentration. pressure gradient, mass flow rate, vorticity in combined pdf/eof were investigated. the shear stress of the wall depended on three parameters (effective electric double layer thickness, edl vorticity thickness, and edl displacement thickness. their results indicate to (1) the distribution of electro-osmotic potential ψ* is a relationship (function) of α (the ionic energy parameter) only. (2) they defined an effective electric double layer thickness as a function of α (ionic energy parameter) and clarify that the edl effects are confined to a region x≤ edl thickness. (3) defect in mass flow rate because of the distribution of velocity within edl, this defect depended on edl displacement. (4) for combined eof/pdf, they explained that using helmholtz velocity as an appropriate condition between the electric double layer is completed and bulk flow. ng and tan, (2006) [5] numerically investigated a single rectangular microchannel with electrical double layer (edl) impact. two models poisson–boltzmann model (pbm) and nernst–planck model (npm) additional to navier–stock equations were used to analyze the edl effect in the channel. in comparison between the two models, it was found that the poissonboltzmann model is better than the nernst-planck model in terms of the cost (ram and cpu). in addition, the p-b-m showed less contradiction of modeling electric double layer a far about surface of the microchannel. they concluded that reducing friction confidence at an increase the schmidt number (sc), the electric double layer (edl) effects lead to an increase in the schmidt number and hence the decrease in friction coefficient. thus, the poisson–boltzmann model(pbm) is still an attractive model to compute the electrical double layer (edl) effect in the microchannel. dayong y. (2011) [6] analytical solution of velocity distribution and potential for combined pressure-driven flow and electroosmotic flow in microchannel. the mathematical model to simulate fluid flow consisted of the navier stokes and the poisson boltzmann equations, which were solved by using the finite element method in matlab software. their results showed that at combined eof/pdf the distribution of velocity is parabolic and compound of plug-like when the fluid is steady-state, the distribution of velocity is observed to be plug-like and similar to the edl potential profile even in the case of pure eof. their results supply the guidelines to applications of combined flow (eof/pdf) in microchannel chips. nandy et al. (2013) [7] experimental study to improve the heat transfer performance by decreasing hydraulic diameter size or by using better thermal conductivity for working fluid in microchannel heat exchanger addition to studying the testing and design of microchannel heat exchanger (mche). working fluids are distilled water, water nanofluid (al2o3) at volume concentration 1%, 3%, and 5%, water nanofluids (sno2) at volume concentration 1%. they concluded to enhance the heat transfer rate add nanoparticle in the fluid, water 50% (al2o3) and water-nano fluids 1% (sno2) greater absorption the heat with 9% and 12% comparison with base fluid also higher overall heat transfer coefficient than the base fluid. mushtaq et. al. (2017)[8] applied numerical investigation of two electrolyte solutions are water and pbs (phosphatebuffered-saline solution) through the square microchannel by solved navier stokes equation, laplace and poisson equation with the pure electro-osmotic flow. it was found that the water solution gives lower flow and velocity compared with pbs, and it was noticed a very small increase in temperature because of the simple effect of joule heating. moreover, it was concluded that zeta potential and electric field have a great effect on flow rate. mushtaq et. al. (2017) [9] studied the pure electro-osmotic flow through a microchannel with contractions to contribute to an increase in the biomolecules flow corresponding to the used different shapes (rectangular, trapezoidal, curved, and triangular) of contractions. cosmol software to analyze the flow behavior was used. their results showed that the distribution of velocity for triangular contraction has higher values of flow velocity, and highest compared to other geometries of contractions. in addition, it was concluded that the velocity of flow increased with the increasing of zeta potential and electric field. ahmed a. et al. (2019) [10] numerically investigated of scaling effect (surface roughness effects) of parallel flow in the square microchannel heat exchanger on thermal and hydrodynamic performance at various hydraulic diameters. it was concluded that the impact of surface roughness leads to improve thermal performance and increase in pressure difference. the effect of roughness reduced with increment re and hydraulic diameter. ahmed a. et al. (2019) [11] numerically studied of scaling effect (slip flow effects) in counter flow mche on performance at different geometries (square, trapezoidal, triangle, and circular). in addition, changing the size of a channel on thermal and hydrodynamic performance were studied. their results indicated that the trapezoidal channel has higher overall performance compared to other shapes. moreover, triangle shape has the higher effect on slip flow and hence the square shape. it was found that greater slip flow is related to small nomenclature a cross-section area (𝑚2) greek symbols cp specific heat (j/kg.k) p density dh hydraulic diameter (µm) µ viscosity h height (µm) ζ zeta potential k thermal conductivity (j/k) ψ electric potential l length channel of heat exchanger (µm) κ debye-huckel parameter m mass flow rate (kg/s) λ edl thickness p pressure (pa) ε permittivity p.p pumping power (watt) subscripts q heat transfer rate (watt) eof electro-osmotic flow re reynold number pdf pressure driven flow t temperature (k) edl electric double layer t separating wall thickness (µm) i inlet u velocity in x-direction (m/s) o outlet v velocity in y-direction (m/s) c cold fluid w velocity in z-direction (m/s) h hot fluid 68 dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 velocity and hydraulic diameter. thus, the slip flow causes an increase in pressure difference and pumping power. qingkai et al. (2020) [12] theoretically investigated heat transfer and flow of nano fluid in a horizontal microchannel in combination with the effect of electric double layer and magnetic field. momentum equation with the presence of edl effect were solved . in addition, nanoparticle volume fraction, temperature, velocity, the brinkman number (br), hartmann number ha, the impact of parameter k, and various physical quantities were discussed thoroughly. the finding indicates that the electric double layer and magnetic field may be used to control the heat transfer and flow in the microchannel. the heat improvement depends on the temperature applied on the wall and the brinkman number. the magnetic field impact on friction coefficient and nanoparticle volume fraction can disregard the impact of magnetic field on sherwood number and nusselt number. ahamed c. et. al. (2020) [13] numerically studied of electro-osmotic /pressure-driven flow with triangular obstacles (block) through rectangular microchannel by alternative technique cfd and modified ibm to solve navier stokes equation with poisson boltzmann equation and nernst plank equation. they used hybrid technique to improve mixing efficiency by the passive and active integration ways. their findings refer to (a) the mixing efficiency depended on a change in several triangular blocks, the zeta potential of surface, and edl thickness (b) mixing efficiency reduced with an increase in an applied electric field, reynold number, and peclet number. (c) mixing efficiency is higher from 28.2 – 50.2 % at increment the number of a block from (15). 2. problem description: in this paper, a three-dimension parallel flow square microchannel heat exchanger (mche) as shown in fig. 1 is modeled. study one unit of microchannel heat exchanger consists of hot and cold fluid as shown in fig. 2. the length of the heat exchanger is l=1mm and its hydraulic diameter (10-50µm). the thickness of the wall between the hot channel and cold channel equal t=3µm, while the ratio between the velocity of pressure-driven to the velocity of electro-osmotic flow is 0.96. the temperature of inlet hot and cold are 373 k, 293 k receptivity. the zeta potential of the channel surface (-0.2 volt), and the applied field electric ez on working fluid ( 𝟏𝟎𝟔) volt/m. (d) the electric double layer overlaps effect on mixing efficiency. their findings are useful in a lot of fields (biomedical, cooling of microchips, deoxyribonucleic acid hybridization and biotechnological … etc. most of the previous papers theoretical and practical investigated heat transfer and flow characteristics in the single microchannel. this study investigates the effect of electric double layer (edl) at two values of ionic concentration through parallel flow microchannel heat exchanger (pmche) and determines at any size of microchannel heat exchanger stops edl effect or is the slight effect. compared the results with no electric double layer (edl) effect (pure pressure-driven). figure .1 schematic model of microchannel heat exchanger figure . 2 a unit of heat exchange consists of the hot and cold channel [14]. 2.1. electric double layer (edl) the electrical potential surface for a solid wall of the microchannel and the liquid has quantities of ions, this leads to attraction of the counter ions in dilute liquid to electrostatic charges of surface to create an electric field. the order of electrostatic charge and ions of liquid is called electric double layer (edl) as shown in fig. 3. there are two types of ions in term of motion, for the compact layer (the layer near of surface) the ions are immobile, and in the diffuse double layer (ddl) the electric field less influence on the ions (mobile). at the dilute liquid flow through the microchannel, the mobile ions of the electric double layer create an electric current (streaming current) to flow with liquid flow. in case the streaming potential of electro-osmotic is very small compared to the applied external electric field. the gathering of the ions in direction of flow sets up an electric potential and electric field together known streaming potential, this caused in creates a current is called conduction current. the conduction current direction is counter to the direction of liquid flow. the maximum value of the thickness of the electric double layer (edl) 1µm depending on the properties of the liquid are (a) ionic concentration (b) temperature of the dilute liquid, and (c) zeta potential of the surface. to show characterize of the electric double layer (edl) effects used the debye-huckel parameter k [13]. 1 𝑘 represent the thickness of the electric double layer (edl) kumar [15]. dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 69 figure . 3 scheme formed of electric of double layer on the surface wall [16] 3. mathematical formulation governing equations 3d steady-state, incompressible and laminar flow, the following equations are solved to calculate the distributions of velocity, temperature, and edl distribution for parallel flow microchannel heat exchanger. poisson’s equation according to the theory of electrostatics, the relationship between ψ and ρe is given by the poisson’s equation sheikhizad et al. [17], which for a rectangular channel 𝜕2𝛹 𝜕𝑥2 + 𝜕2𝛹 𝜕𝑦2 + 𝜕2𝛹 𝜕𝑧2 = 𝜌𝑒 𝜀𝜀ₒ (1) ε is the dielectric constant of the medium εₒ is the electric permittivity of a vacuum. 𝜌𝑒 is the net volume charge density, we have? ni=nₒi 𝑒𝑥𝑝(− 𝑧𝑖𝑒𝛹 𝑘𝑏𝑇 ) (2) ρ𝑒 =(𝑛+ − 𝑛−) = −2𝑛ₒ𝑧𝑒𝑠𝑖𝑛ℎ( 𝑧𝑒𝛹 𝑘𝑏𝑇 ) (3) 𝑛+ 𝑎𝑛𝑑 𝑛− are a concentration of cations and anions, respectively kb boltzmann’s constant =1.3805 ∗ 10−23𝐽𝑚𝑜𝑙−1𝐾−1 e electron charge = 1.6021 ∗ 10−19𝐶 nₒi bulk concentration poisson-boltzmann eq. (1) become ∂2ψ ∂x2 + ∂2ψ ∂y2 + ∂2ψ ∂z2 = 2nₒze εεₒ sinh zeψ kbt continuity equation: [5] ∂u ∂x + ∂v ∂y + ∂w ∂z = 0 (4) momentum equation x-direction u ∂u ∂x + v ∂v ∂y + w ∂w ∂z = μ ρ ( ∂2u ∂x2 + ∂2u ∂y2 + ∂2u ∂z2 ) − μ ρ ∂p ∂x (5) ydirection u ∂v ∂x + ∂v ∂y + ∂v ∂z = μ ρ ( ∂2v ∂x2 + ∂2v ∂y2 + ∂2v ∂z2 ) − μ ρ ∂p ∂y (6) the applied electric field (𝐸𝑧 𝜌ₑ ) u ∂w ∂x + v ∂w ∂y + w ∂w ∂z = μ ρ ( ∂2w ∂x2 + ∂2w ∂y2 + ∂2w ∂ z2 ) − 1 ρ ∂p ∂z − ezρₑ (7) energy equation: u ∂t ∂u + v ∂t ∂v + w ∂t ∂w = k ρcp ( ∂2t ∂x2 + ∂2t ∂y2 + ∂2t ∂z2 ) (8) the heat transfer rate of a microchannel heat exchanger between hot and cold [1]: 𝑄 = 𝑚𝐶𝑝∆𝑇 (9) the effectiveness (ε)= qact qmax = ch(thi−tho) cmin (thi−tic) = cc(tco−tci) cmin(thi−tci) (10) the overall performance of mche can be calculated from eq. [1] η = ε ∆pt (11) ∆pt=∆pc+∆ph=(pin,c-po,c)+(pin,h-po,h) (12) the boundary conditions [17] at inlet of the channel z = 0, then u = 0 v = 0 w= uin & t = tin. at the outlet of the channel z = lch and the flow is fully developed, then 𝜕𝑢 𝜕𝑧 = 0 𝜕𝑣 𝜕𝑍 = 0 𝜕𝑤 𝜕𝑧 = 0 & 𝜕𝑇 𝜕𝑧 = 0 for three cold walls adiabatic (sides walls and up the wall) and three hot walls adiabatic (sides walls and down wall) conditions are applied: 𝑢 = 0 𝑣 = 0 𝑤 = 0 𝜕𝑇 𝜕𝑧 = 0 at x=0, 𝛹 = 𝜁ₒ x=w, 𝛹 = 𝜁ₒ at y=0, 𝛹 = 𝜁ₒ at y=h, 𝛹 = 𝜁ₒ for the up wall of the hot channel and down a wall of the cold channel 𝛹 = 𝜁ₒ 4. properties of material: water is a working fluid with aqueous kcl solution at the ionic concentration ( 10−4 m, 10−6 m ), vacuum permittivity (f/m) 8.85 ∗ 10−12 , dielectric constant ε 80 and 6.39 ∗ 10−10 the permittivity of water (c/v*m). the data of the fluid (water) input by creating a user defined function (udf). 70 dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 table 1. shows the properties of dilute liquid and silicon. material density (𝐾𝑔 𝑚3⁄ ) cp (𝐽 𝐾𝑔. 𝐾)⁄ k (𝑊 𝑚. 𝐾)⁄ µ (𝐾𝑔 𝑚. 𝑠)⁄ dilute liquid 997 4182 0.605 0.9e-03 silicon 2329 700 148 5. numerical solution: the system of governing equations and the poisson-boltzmann equation and boundary conditions are numerically solved using the finite volume method (fvm). simple algorithm is used to solve the problem of velocity-pressure distribution and udf to solve poisson-boltzmann equation to study effect electric double layer (edl). a fluent19 software has been used to do the numerical solution. table 2 shows independent grid size for hydraulic diameter (20μm) and effect on the solution results. table 2. mesh independent mesh size outlet temperature (k) of hot channel outlet temperature (k) of cold channel mesh 1 (size element =5μm) 318.253 347.748 mesh 2 (size element =3μm) 318.287 347.573 mesh 3 (size element =1μμm) 318.204 347.302 mesh 4 (size element = 0.8μm) 318.201 347.30 6. results and discussions numerical simulations of heat transfer and fluid flow problem were executed by using the commercial computational fluid dynamic (cfd) package. the governing equations for liquid flow were solved by finite volume method (fvm), and the simple algorithm has been used to solve the problem of velocity-pressure coupling. user-defined function (udf) has been employed to solve the poisson-boltzmann equation to study the combination eof/pde flow through mche. the thickness of the electric double layer plays a significant role in combined electroosmotic / pressure-driven flow due to its effect on the flow, temperature difference, and total pressure drop. the thickness of the electric double layer can be estimated from debye huckel parameter κ, such refer 1/κ to edl thickness λ. the relation between edl thickness and ionic concentration m is reversed which the increase in the ionic concentration of solution leads to a decrease in edl thickness (λ). the parameters will be used in the investigation shown in table 3. the parameter using in this paper are shown in table 4. table 3. the parameters using in this paper. the name value the dielectric constant of the fluid 80 permittivity of vacuum 8.85 * 10−12 c/v*m the permittivity of fluid (water) 6.93*10−10 c/v*m electric field 106 volt/m zeta potential -200 mv ionic concentration 10−4 & 10−6 m charge of electron -1.602*10−19 c valence (z) 1 thickness of edl 32 nm, 324 nm table 4 shows the percentage change (pure pdf and combined pdf /eof) for square mche of the variation parameters with the hydraulic diameter at two values of concentration. the percentage change of pressure drop calculated from the following equation: the percentage change= (∆p𝐸𝑂𝐹&𝑃𝐷𝐹−∆𝑃𝑃𝐷𝐹) ∆𝑃𝐸𝑂𝐹&𝑃𝐷𝐹 the other parameter calculated with the same method. table 4. average percentage change of parameters parameters the percentage change % at c=10−4 the percentage change % at c=10−6 total pressure drop 31.09 42.71 effectiveness 19.26 35.11 overall performance 20.46 6.97 to validate the work of user-defined function (udf) that was used to solve poisson boltzmann equation and applied electric field compared the present model with pure electro-osmotic in microchannel [8]. the model presented in [8] is a microchannel that has a hydraulic diameter of 100 μm, the width of channel 100 μm, the height of microchannel 100 μm, and the length 500 μm. they used a glass microchannel with zeta potential -0.1 volt and the water as a working fluid with ionic concentration 3.727 ∗ 10−6 m and applied electric field 100000 volt/m. the agreement between a present model and that for [8] is very good, and the percentage of the error 2 %. fig. 4 shows the comparison between results of the data of [8] for the velocity of electroosmotic with a width of microchannel and result of the present model. figure .4 for the present model and that for [8]. to check the numerical model validity, verification was made by solving the model presented in [18] a compared the results. the model presented in [18] is a square microchannel at combined flow (electroosmosis flow and pressure-driven flow) with a hydraulic diameter of 25 μm, channel height 25 μm, channel width 25 μm, and length 100 μm with ∆p/dx = 105 pa/m , an inlet temperature of 289 k, and molar concentration 10−4 m, 10−5 m, zeta potential ζ = 150, 200 mv. fig. 5 shows the comparison between results of the data of [18] for velocity distribution with a width of microchannel at different ionic concentrations. it can be seen that from this fig. 5 there is a good agreement between the 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0 10 20 30 40 50 60 70 80 90 100 110 v e lo ci ty o f e le ct ro o sm o ti c width of microchannel (cm) mushtaq [8] present model dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 71 results of the present model and that for [18] and the error between the model presented and a result of [18] less than 5 %. figure .5 for the present model and that for [18]. to show the distribution of velocity, pressure, and temperature using contours on created planes with length and width of the microchannel heat exchanger. fig.6 explains the velocity distribution along the microchannel of pfmche (y-z) plane at the small size of channel dh=10 μm due to the ratio of edl thickness to channel height is larger especially when higher zeta potential (-200 volt) and low ionic concentration. it can be noticed from this figure that the flow velocity in a center is maximum and minimum toward the wall as a result of the friction and the edl field is opposite of the flow direction, this causes a disabled to flow. figure .6 contour explains the distribution of velocity (m/sec) at pfmche on (y-z) plane at dh=10 μm and re=30. fig. 7 represents the distribution of flow velocity for many planes (x-y) along hot and cold channels of parallel flow mche when dh=10 μm and re=50. from fig. 6 it is observed that the velocity at the center of the channel is higher and decreasing toward walls due to friction effects and the edl field. maximum velocity at the inlet flow and minimum value of the velocity at the outlet channel is observed due to losses. figure .7 contour represents the variation of velocity (m/s) along the hot and cold channels at parallel flow mche, dh=10 𝛍m, and re=30. fig. 8 shows (z-y) plane for the pressure drop distribution contour at the same value of hydraulic diameter and re along cold and hot channels of pfmche. it can be concluded from the figure that, the pressure drop reduced with the flow as a result of losses due to friction and dynamic friction. figure .8 contour pressure distribution along the cold channel and hot channel of parallel flow mche for dh=10 𝛍m and re=30. fig. 9 displays the distribution of temperature contours along the length of the channel with a parallel flow microchannel heat exchanger. the inlet fluid of hot channel 373 k, and inlet fluid of cold channel 293 k at hydraulic diameter 10 μm. it can be seen from fig. 9 that, there is an increment in heat transfer and temperature difference with the dilute liquid flow, and reach a high value in the channel end due to heat exchange from the hot liquid to cold liquid. 0 5 10 15 20 25 30 0 0.002 0.004 0.006 0.008 0.01 w id th o f ch a n n e l μ m velocity m/s result of present model at 10 e -05 result of [18] 10 e -05 result of present model at 10 e-04 result of [18] 10 e-04 72 dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 figure .9 contour of temperature distribution (k) for many planes of parallel flow mche dh=10 𝛍m and re =50. fig. 10 explains the variation of the total pressure difference ( ∆𝑃𝑡) with hydraulic diameter for unit parallel microchannel heat exchanger at two cases of driven flow (electro-osmotic/pure pressure-driven flow) with two value of ionic concentration (10−6, 10−4) m. from this figure, it can be observed that the total pressure drop declined with the increase of hydraulic diameter for two cases as a result of an increment in the crosssectional area of a mche. in addition, it can be shown that higher pressure drop at combined eof/pdf comparison with pure pressuredriven due to increase in velocity of liquid flow which caused larger losses in pressure. a low concentration leads to higher pressure drop due to an increase in edl thickness at low concentration can be seen from fig. 10 that a low concentration leads to higher pressure drop due to an increase in edl thickness at low concentration, with notice that the impact of edl lower with increasing in hydraulic diameter depended on the ratio between the thickness of edl to the height of the channel, at dh > 40 μm begin the effect of edl stop due to the large height of microchannel compared with the thickness of edl. figure. 10 variation of total pressure drop (kpa) with a hydraulic diameter (μm). fig. 11 shows the temperature difference variation ( ∆𝑇) for pure pdf and combined flow with a hydraulic diameter at two values of ionic concentrations (two values of edl thickness). from the figure, it can be concluded that the temperature difference decrement with increasing hydraulic diameter for all cases. can be noticed from fig. 11 that, increase in average temperature difference at combined flow compared with pdf especially at higher edl thickness as a result of the flow of electric double layer field is the opposite direction to the flow in the channel center, this lead to obstructing inflow at the surface of a channel at combined flow (eof/pdf). figure .11 variation of average temperature difference with the hydraulic diameter (μm). the relation between the effectiveness (ε) and hydraulic diameter is shown in fig. 12. it can be observed that the effectiveness is decreased with the increase of hydraulic diameter due to a decrease in temperature difference with the increased size of the channel. moreover, the effectiveness in the case of combined flow is higher than that for pure pdf and the effectiveness increased with decreasing the concentration. the increase in effectiveness in presence of edl is due to an increase in temperature difference when mixed eof/pdf and the slight effect on effectiveness figure .12 variation of effectiveness with a hydraulic diameter (μm). 0 100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30 35 40 45 50 55 ∆ p ( k p a ) dh (μm) pd eof/pdf, c=10e-4 eof/pdf, c=10e-6 0 5 10 15 20 25 30 35 40 5 10 15 20 25 30 35 40 45 50 55 ∆ t ( k ) dh pd eof/pdf, c=10^4 eof/pdf, c=10^-6 0 0.1 0.2 0.3 0.4 0.5 0.6 5 10 15 20 25 30 35 40 45 50 55 ε dh pd eof/pdf, c=10e-4 eof/pdf, c=10e-6 dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 73 fig. 13 represents the variation of the performance index ( 𝜂) with a size of a microchannel. it can be seen the performance index increased with increasing hydraulic diameter for all cases due to the decrease in total pressure with increased channel size. furthermore, the impact of electric double layer thickness has a significant impact on overall performance, which leads to a decrease in performance index due to the increase in total pressure difference at combined driven. the performance index is observed to be decreased in small size of microchannel compared with pure pressure-driven and improvement in performance at large size of microchannel heat exchanger because lower the ratio between a thickness of edl to the height of microchannel. figure. 13 variation of overall performance with a hydraulic diameter(𝛍m). the relationship between an average heat transfer rate ( 𝑄𝑎𝑣𝑔. ) , hydraulic diameter for unit microchannel heat exchanger for two cases pure pressure-driven and mixed driven flow is shown in fig. 14. it can be concluded that the heat transfer rate is increased with the increasing of hydraulic diameter for all cases as a result of an increment in the crosssectional area of a mche. in this figure, the average heat transfer due to the lost heat is not equal to the heat gain a combined pdf/eof due to the formation of the edl, which means an increase in thickness of the separator wall. fig. 14 shows enhancement in the average heat transfer rate in combined pdf/eof at higher edl thickness (low ionic concentration) due to an increase in the lost heat of the hot channel. figure .14 variation of average heat transfer (watt) with a hydraulic diameter fig. 15 shows the variation of the pumping power ( p. p) with hydraulic diameter. in addition, it can be observed that the relation of pumping power with channel size is steady as a horizontal line for all cases. this means the change in hydraulic diameter has no impact on pumping power. can be seen from fig. 15 that an increase in the pumping power at combined flow due to an increase in total pressure drop and flow rate of liquid and higher pumping power at low ionic concentration. figure .15 variation of pumping power (watt) with a hydraulic diameter. fig. 16 expresses the variation of the performance factor ( η ∗) with hydraulic diameter. it can be seen from this figure that the performance factor increment with increasing hydraulic diameter due to an increase in the area of the microchannel. moreover, it shows an increase in the heat exchanged with remained pumping power at a constant value with changed channel size. for mixed pdf/eof flow, it can be seen that the relationship between performance factor and size of the microchannel is linear, also notice that reduced in performance factor especially when the small size of microchannel due to the higher effect of edl with enhancement in performance factor at a large hydraulic diameter and low concentration. figure .16 variation of overall performance with a hydraulic diameter 0 0.000001 0.000002 0.000003 0.000004 0.000005 0.000006 0.000007 5 10 15 20 25 30 35 40 45 50 55 η dh pd eof/pdf, c=10e-4 eof/pdf, c=10e-6 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 5 10 15 20 25 30 35 40 45 50 55 q ( w a tt ) dh pd eof/pdf, c=10e-4 eof/pdf, c=10e-6 0 0.00001 0.00002 0.00003 0.00004 0.00005 0.00006 0.00007 0.00008 0.00009 0.0001 5 10 15 20 25 30 35 40 45 50 55 p .p dh pd eof/pdf, c=10e-4 eof/pdf, c=10e-6 0 500 1000 1500 2000 2500 5 10 15 20 25 30 35 40 45 50 55 η * dh pd eof/pdf, c=10e-4 eof/pdf, c=10e-6 74 dunya a. mohammad, mushtaq i. husan and ahmed j. shkarah /al-qadisiyah journal for engineering sciences 14 (2021) 066–074 fig. 17 explains the variation of a temperature difference as a comparison between hot and cold channels with a hydraulic diameter at two values of ionic concentration. from the figure, it can be noticed that for pressuredriven flow temperature difference is similar for the two-channel (hot and cold). however, the temperature difference for a hot channel is higher than cold channel especially for low ionic concentration depending on edl thickness. the reason is attributed to the electric double layer thickness of an increase with an increase in temperature inlet of liquid. the consequences, leads to make the loss of heat is not equal to the heat gain in the case of presence the electric double layer depended on ionic concentration and temperature inlet of liquid. figure .17 variation of temperature different for hot and cold channel with a hydraulic diameter (μm). conclusions: a numerical solution to study the effect of the electrical double layer (edl) on the thermal and hydraulic performance of parallel flow microchannel heat exchanger by solving 3d navier-stokes and 3d poisson-boltzmann equation was conducted. the results can be concluded that: 1. increasing in total pressure drop at combined flow (electroosmotic and pressure-driven flow) for parallel flow microchannel heat exchanger especially at a higher thickness of the electric double layer (low ionic concentration and higher zeta potential. 2. notice the effects of edl are very slight at large size of hydraulic diameter dh > 40 μm depending on the ratio of a thickness of electric double layer to the height of microchannel. 3. enhancement in average heat transfer rate and effectiveness. 4. higher in pumping power at combined driven flow. 5. the thickness of the electric double layer has an important role in the effect on the flow rate and performance of the microchannel heat exchanger. 6. for pure pressure driven, the temperature difference for hot channel is equal to the temperature difference for cold channel (the heat gain is equal to heat loss). 7. for combined flow (pdf/eof), the temperature difference for hot channel is higher than cold channel. references [1] mushtaq i. hasan, a. rageb, m. yaghoubi, and homayon homayoni, influence of channel geometry on the performance of a counter flow microchannel heat exchanger, international journal of thermal sciences, 48 (2009) 1607–1618 [2] claudio berli, theoretical modelling of electrokinetic flow in microchannel networks, colloids and surfaces a: physicochemical. eng. aspects 301 (2007) 271– 280l. [3] chun yang and dongqing li, electrokinetic effects on the liquid flow in rectangular microchannels, journal of colloid and interface science, 149 (1997) 95107. [4] prashanta dutta and ali beskok, analytical solution of combined electroosmotic/ pressure driven flows in two-dimensional straight channels: finite debye layer effects, analytical chemistry j., 73 (2001) 1979-1986. [5] ng and tan, numerical analysis of edl effect on heat transfer characteristic of 3-d developing flow in a microchannel, numerical heat transfer, part a, 49 (2006) 991–1007. [6] dayong yang, analytical solution of mixed electroosmotic and pressure-driven flow in rectangular microchannels, key engineering materials , 483 (2011) 679-683. [7] nandy putra1, wayan nata septiadi, gerry julian, ary maulana and ridho irwansyah, an experimental study on the thermal performance of nano fluids in microchannel heat exchanger, international journal of technology, 2 (2013) 167‐ 177. [8] mushtaq i. hasan, alaa m. lafta, ahmed j. shkarah, numerical investigation of electroosmotic flow in microchannel, international review of mechanical engineering (i.r.m.e), 11(8) (2017) . [9] mushtaq i. hasan, alaa m. lafta, ahmed j. shkarah, study the electroosmosis flow in microchannel with contractions of different geometries, proc. of the 2nd int. sci. conf., southern technical university, (march 2017). [10] ahmed a. ali, mushtaq i. hassan and ghassan adnan, study surface roughness on the overall performance of parallel flow microchannel heat exchanger, the university of thi-qar journal for engineering sciences, 10 (1), 2019. [11] ahmed a. ali, mushtaq i. hassan, and ghassan adnan, numerical investigation of the slip flow effect in counter-flow microchannel heat exchanger with different channels geometries, first international scientific conference of alayen university (iscau), 2019. [12] qingkai zhao, hang xu, and longbin tao, flow and heat transfer of nanofluid through a horizontal microchannel with magnetic field and interfacial electrokinetic effects, european journal of mechanics/b fluids, 80 (2020) 72-79. [13] ahamed saleel, asif afzal, mostafa abdel mohimen, manzoore elahi, h. fayaz, numerical investigation on pressure-driven electroosmatic flow and mixing in a constricted microchannel by triangular obstacle, international journal of numerical methods for heat & fluid flow, (9 june 2020). [14] mushtaq i. hasan, effect of variable fluid properties on the hydrodynamic and thermal characteristics of parallel flow microchannel heat exchanger, journal of university of thi-qar, 10 (4). dec. (2015). [15] s. kumar, the edl effect in microchannel flow: a critical review, international journal of advanced computer research, 3 (4), (2013). [16] ferrás, a. afonso, m. alves, j. nóbrega and f. pinho, electro-osmotic and pressure-driven flow of viscoelastic fluids in microchannels: analytical and semianalytical solutions, physics of fluids 28 (2016) 093102 [17] mehdi sheikhizad and mohammad kalteh, heat transfer investigation of combined electroosmotic/pressure driven nanofluid flow in a microchannel: effect of heterogeneous surface potential and slip boundary condition, journal pre-proof, (2019). [18] reza monazami and mehrdad t. manzari, analysis of combined pressuredriven electroosmotic flow through square microchannels, microfluid nanofluid, 3 (2007) 123–126. article al-qadisiyah journal for engineering sciences 13 (2020) 144–152 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author: tel. + 9647807857061 e-mail address: alaa.almosawi@qu.edu.iq (alaa l. hashem) https://doi.org/10.30772/qjes.v13i2.654 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. experimental investigation of green roof impact on buildings energy in hot climate farah abdul kadhum malika, alaa liaq hashem a* a department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq. a r t i c l e i n f o article history: received 06 may 2020 received in revised form 22 june 2020 accepted 25 june 2020 keywords: green roofs eco-roofs building energy a b s t r a c t green roofs are a layer that effectively working on blocks of solar radiation from entering the building's structure below partially. its work as a passive cooling technique, and have the potential to reduce the high surface temperature of conventional roofs because of the soil thermal resistance, evapotranspiration, and several effects for foliage shading. this affects the heat flux flow of the roof that in turn influences the indoor thermal conditions and the building energy demand. the research goals are to test the influence of the green roof on reducing heat transfer to the interior of heavy structural buildings. the experimental part was done to examine the effect of the green roof and compare it with a standard roof under influence of ambient air temperature, solar radiation, and wind speed and test the effect of the green roof on reducing heat transfer inside the building. the model site was at the diwanyah city (latitude: 31.9868 and longitude: 44.9215), the engineering college campus, qadisiyah university. the experimental setup includes two cubicles, with equal internal volume values (163cm * 163cm * 105cm). the experimental results showed for the period 5-8 september 2019. the maximum zone temperature was 46.4 °c for traditional roof and 37.06 °c for the green roof at 3:24 p.m. the results showed that the maximum internal temperature was 46.97 °c and 36.42 °c for the traditional roof and green roof respectively at 3 p.m. also, the results for period 18-21 july 2019 noted that the zone temperature decreased by 7.5 °c and the maximum temperature of the internal traditional standard roof’s surface is 45.66 °c and 37.41 °c for the green roof. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction in iraq, the buildings were constructed mainly from heavily weighted materials, with its presence in an environment in which summer is longer than winter and temperature differences between night and day are few, the overcooling problem exacerbates every year. this explains the high-energy consumption in this sector, which reached 38% of total energy production within the year 2018 [1]. striking a balance between reducing energy consumption and provide a comfortable atmosphere and from other side restoring the environmental balance through the use of green roofs is an idea that was used in iraq 6 thousand years ago in the hanging gardens of babylon. green roofs are a passive cooling technique that minimizes incoming solar radiation from reaching the building structure below. green roofs also referred as vegetated roofs [2], eco-roofs, roof gardens or living http://qu.edu.iq/ mailto:alaa.almosawi@qu.edu.iq https://doi.org/10.30772/qjes.v13i farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 145 roofs [3, 4]. it is basically, a roof with plants in their final layer. green roofs have a large impact on the inner roof temperature because of several effects: foliage shading, soil thermal resistance and evapotranspiration, etc. therefore, the heat flux through the roof reduced, leads to influences on the building indoor thermal conditions and energy demand. the modern green roofs are designed and developed widely by germany [5], where 10% of buildings use green roof construction technology [6]. presently, countries such as canada, the united states, australia, japan, and singapore are also taking a serious initiative to use green roofs in modern buildings and modify old buildings. in the city of toronto, canada, the use of green roofing is imposed on the area between 20% and 60% of the overall roof area [7]. similarly, in the city of tokyo, japan, the process of green roof design is accelerated by commissioning all new buildings to construct these roof designs. for instance, private buildings and having area higher than 1000 square meters and general buildings having an area higher than 250 square meters must be green to be equivalent to 20% of the roof or pay a fine of $ 2,000 per year [6]. in the city of portland, usa, all new buildings must be constructed with a green roof covering no less than 70% of the roof [8]. due to the great importance and benefits offered by the green roofs, many previous studies and researches are showing their importance. a detailed description of thermal performance, as well as runoff measurements of green surfaces in the city of toronto, was provided by liu and minor [9]. two extensive green surfaces were used with a lightweight growth medium and soil depth ranges 75-100 mm. although vegetation was minimal during the first year of the green roof, the flow of heat through the roof was reduced by 70-90% in the summer and 10-30% in the winter. takebayashi and moriyama [10] conducted their study in the state of los angeles in august 2004. a green roof (one with plants and one with bare soil surface that does not contain plants) and cement concrete surfaces were used. it was observed that the sensible heat fluxes on the green surface are little due to the huge latent heat fluxes through evaporation. saiz, et al. [11] used life cycle assessment to estimate the advantages, particularly in terms of enhanced energy consumption, due to the use of a green roof to a multistory residential building located downtown in the city of madrid, spain. the findings indicated that environmental effects decreased more considerably in categories related to the generation of electricity and the use of a green roof is found to decrease energy consumption by around 1% per year. it might be noticed that such energy-saving is not large due to the fact that the green roof was used to only 16% of the buildings exposed surface area. attia and mahmoud [12] presented the green surfaces as a civilized landscape of healthy and productive cities, which are considered a solution to economic, environmental, and social problems in developing cities. the results showed that the most important benefits of agriculture in the roofs of houses is the economic burden of families, increasing the income of families. as a contribution to reduce pollution, contribute to low temperature, and reduce energy consumption, especially cooling capacity. environmental and social problems in developing cities. the first part of the study deals with a set of tools and design principles that contribute to transforming green surfaces into productive farms. while, the second part deals with successful cases in cairo that includes residential units, gardens, and schools. the results showed that the most important benefits of agriculture in the roofs of houses is the economic burden of families, increasing the income of families. as a contribution to reduce pollution, contribute to low temperature, and reduce energy consumption, especially cooling capacity. jaffal, et al. [13] provided an investigation of the effect of a green roof on the performance of building energy. a model consisted of a single-family house with a green roof was examined and implemented within a building code in order to evaluate soil surface temperatures and the green roof foliage. the authors found that the use of a green roof protects the roof slab from high-temperature fluctuations and extreme temperatures. moreover, in the summer, a passive cooling effect was noticed with an increment in the daily heat losses through the roof by a factor of three using the green roof. it was concluded that the use of a green roof is an effective solution for the reduction of cooling demand and the improvement of thermal comfort. moody and sailor [14] studied the thermal performance of buildings through a model with a green roof. a new parameter was introduced called mechanical benefit of green roofs which is the ratio of energy use to heating, ventilation, and air conditioning of a traditional roof building to a green roof building. based on field data from portland, oregon, the usa which used for validating their green roof model in the energy simulation program. the results showed that the advantages of a green roof depend strongly on the climate and location of the building. la roche and berardi [15] studied the potential of green roofs, in terms of energy saving, using the system different strategies, non-insulated, insulated, and variable insulated system. the system was located and examined in a dry and hot climate with moderate winters. the results showed that the variable green roof insulation was effective as it proved to change thermal capacity in the summer, this system and the system of a non-insulated green roof led to the lowest indoor temperature. the results indicated that the use of green roofs and isolated traditional roof systems in the winter season led to a preserve of high indoor temperature. jim [16] explained the effect of building thermal insulation on cooling by green surfaces. the researcher assumed that buildings with poor thermal insulation are more useful in passive cooling in green roofs. a field experiment was conducted on the roofs of two buildings in the city of hong kong to evaluate electricity consumption for air conditioning in two cases of thermal insulation, one of which is good and the other poor. in addition, the study was included three types of roofing namely simple sedum, herbaceous and peanut, and three falls of snow for summer weather namely apricot, rainy and cloudy. in the event that the thermal insulation construction is not utilized, the cooling load is large throughout the day, and the installation of green roofs causes a significant decrease in the cooling load as well as saving energy consumption. without building thermal insulation, green roofs will act as thermal insulation to restrict the internal heat entering the space. in addition, the water content within the green roof is important to enhance the conductivity and thermal capacity, and thus the heat transfer to the inner space. coma, et al. [17] evaluated the thermal behavior of extensive green roofs by assessing thermal performance and energy consumption of three symmetric house-like rooms, with different roof structure system, located in the city of puigverd de nomenclature a surface area in ( m2) u overall heat transfer coefficient in (w/ m2 k) k thermal conductivity (w m-1 k-1) subscripts q quantity of the heat trans (w) tr traditional 𝑹𝑻 total resistance gr green roof s body thickness (m) c.l cooling load 𝑇1 higher temperature ( k ) lr load reduction 𝑇2 lower temperature ( k ) 146 farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 lleida, spain. one roof includes a traditional flat roof with an insulating layer, while an extensive green roof of 9 cm depth (pozzolana as drainage layer materials and comparing recycled rubber crumbs) was replaced the other two compartments. the results showed that both ceiling systems and extensive green roofs offer, 11.1% and 6.1%, respectively, higher energy consumption than conventional roofing during heating periods the techniques that would reduce the thermal effect caused by the lack of green spaces in the city and the use of green roofs technology was studied by saleem and abdulrasoul [18]. the authors focused on how this reduces the thermal island and especially in hot climates. the finding showed that there is a relationship between increasing the area of green roofs and mitigation in heat where the experiment was conducted in the province of najaf. it showed that the green roofs have the ability to reduce the thermal difference between the countryside and the city. jiang and tang [19] analyzed the thermal and energy performance of the integration of night ventilation and a green roof. the thermal performance of the traditional and green roofs of three experiments on summer and sunny days was compared integrated on/off night ventilation mode. the results showed that a clear reduction in heat gains and the indoor air temperature was observed by integrating green roofs and night ventilation on a sunny day, while on a rainy day this reduction was not considerable. the reason behind this is that the cooling potential of night ventilation and a green roof extremely relies on the climate and thermal mass. the role of green space systems in achieving energy consumption related to buildings as well as carbon emissions was investigated by besir and cuce [20]. the authors assessed the multiple advantages of green roofs and facades such as shading, thermal insulation, and evaporation and the effect of evaporative cooling on green surfaces in reducing the demand for cooling in buildings. it was found that it is possible to reduce the solar heat gain into the buildings by about 80% from the green roof in the summer, that is, the green roof consumes energy of 2.2 to 16.7% of the traditional roofs in the summer. also, a difference in temperature was found between the traditional roof and the green roof, by about 4 ° c, during the winter season. 2. problem description the experimental set up consists of two cubicles, with identical internal volumes (160 × 160 × 160 cm) as shown in fig. 1. their foundations are concrete reinforced slabs of (160 × 160 × 10 cm). the compositions of the walls show the following layers from inside to outside: cement mortar, hard bricks (24 × 12 × 8 cm), and cement mortar as internal coating. the roof is the only construction surface that differs among the studied cubicles. 2.1. traditional room the area identified for both models is buried with rough soil (subbase), after which the rough soil was compacted by steel wheel rollers to become one level and 10 cm high to be ready for construction. laying the building floor consisting of concrete reinforced slabs (1.60 m × 1.60 m× 0.10 m) prefabricated for both models. the construction of the structure (walls) began directly above the previously precast floor, and the construction was carried out using two rows of hard bricks (24 cm x 12 cm x 8 cm) and iraqi cement. the walls 140 cm high for both models, while one side left open for laying the door as shown in fig, 2. laying the base of the roof over the building structure for both models consisting of concrete reinforced slabs (1.60 m × 1.60 m× 0.10 m) prefabricated, and then the structure was built on the roof with a height of 36 cm using hard bricks and cement. then the walls were coated inside and outside with a layer of cement mortar 3:1 for both modules as shown in fig. 3. a pvc door (1.38 m× 0.98 m) was installed in the space designated for both models. figure 1. a 3-d graph of the experimental cubicle, dimensions in cm. the physical properties of the construction material listed in table 1 [21, 22]. the reference traditional insulated flat roof fabricated from multilayers as shown in fig. 4, multi-layers covered the concert slap: layer of moisture resistance (asphalt) is located on reinforced concrete. a layer of 0.75 cm of polyethylene is placed above the asphalt layer, layer of river sand was placed with a thickness of 7 cm, and the final surface is a layer of concrete tiles with a thickness of 3 cm. the spaces between the tiles filled with mastic. figure 2. the construction process of the structure (walls). farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 147 figure 3. covering the walls with cement mortar. figure 5. construction section of the traditional room. figure 4. construction section of the traditional room. table 1. the physical properties of the construction mater. [21, 22] layers thickness (m) material thermal conductivity (w/mk) density (kg/mˆ3) specific heat (j/kg k) internal and external coating 0.02 cement mortar 3:1 0.99 2020 2040 bricks 0.24 hard bricks 0.54 1460 840 reinforced concrete 4:2:1 0.1 composed 1.49 2300 840 concrete tiles 0.03 sand, cement and gravel 1.1 2100 837 water insulation 0.01 asphalt 0.24 1070 1000 insulation 0.0075 polyethylene 0.037 30 1000 river sand 0.07 sand 0.24 1690 1000 water proof protection 0.07 gravel 1.2 1700 920 relieved concrete 0.02 light mortar 0.41 900 1000 1 2 3 4 5 6 7 8 1. external coating by cement mortar 2cm. 2. hard bricks. 3. interior coating by cement mortar 2cm. 4. concrete tiles 3cm. 5. river sand 7cm. 6. polyethylene insulation 0.75cm. 7. water insulation (asphalt) 1cm. 8. reinforced concrete slabs (roof) 10cm. 148 farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 2.2. green room the experimental model structure is identical to the traditional model except for the layers added on the concert slab external surface which different and including the green layer. a layer of asphalt (water insulation) is laid on reinforced concrete. a layer of relieved concrete to obtain a slope of 2 cm thickness was placed over the asphalt layer. then two polyethylene insulation layers of 1.5 cm thick laid on the relieved concrete, a single layer of gravel of 7 cm thickness as a drainage layer, substrate layer of 15 cm thickness, and the vegetation layer as shown in fig. 5. in addition, a water drainage system was done at the end of the roof from the bottom, in order to drain the excess water from the watering process. the drain hole was covered by a group of gravel on the drainage hole from the inside, in order not to drain the soil (growth medium). a type of grassland plant (indian grass) was used as shown in fig. 6, which adapts well to hot and dry climatic conditions during the summer period. moreover, the drip irrigation system was used to preserve plants during the summer period. figure 5. construction section of the green roofs room. the sensors were constructed for evaluating the thermal behavior of both models during experiments to measure the following: internal wall temperatures on the west and south, and the roof; internal and external ambient temperature; and external surface temperatures for the roof. an extra temperature sensor was placed at a height of 1 cm for both the traditional roof and the green roof at a height of 2 cm from the vegetation at the green roof. figure 6. the growth of the grass plant on the surface of the green room. 3. mathematical formulation heat transfer equation: the equation of heat transfer by conduction called fourier law can also be expressed as [23]: 𝑄 = 𝑈𝐴(𝑇1 − 𝑇2) (1) 𝑄 = 1 𝑅𝑇 𝐴(𝑇1 − 𝑇2) (2) 𝑅𝑇 = 𝑅𝑠𝑖 + ∑ 𝑅𝑙𝑎𝑦 + 𝑅𝑠𝑒 (3) 𝑅 = 𝐾 𝑆 (4) where (𝑅𝑠𝑖) represents inner surface thermal resistance equal to 0.13, (𝑅𝑠𝑒 ) represents the external surface thermal resistance equal to 0.04. [22] load reduction (%): the reduction in load gain caused by using a green roof can be calculated as follow: 𝐿𝑅 = 𝑪.𝑳𝒕𝒓.𝒓𝒐𝒐𝒎−𝑪.𝑳𝒈𝒓.𝒓𝒐𝒐𝒎 𝑪.𝑳𝒕𝒓.𝒓𝒐𝒐𝒎 (5) electricity cost savings: electricity cost savings are calculated from the following formula [24]: 𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦 𝑐𝑜𝑠𝑡 𝑠𝑎𝑣𝑖𝑛𝑔 ( 𝐷𝑖𝑛𝑎𝑟 𝑑𝑎𝑦 ) = 𝑐𝑜𝑜𝑙𝑖𝑛𝑔 𝑙𝑜𝑎𝑑 𝑟𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 (𝐾𝑊) ∗ 30 (𝐷𝑖𝑛𝑎𝑟/𝐾𝑊ℎ) ∗ 24(ℎ/𝑑𝑎𝑦) (6) 1 2 3 4 5 6 7 8 9 10 1. external coating by cement mortar 2cm. 2. hard bricks. 3. interior coating by cement mortar 2cm. 4. vegetation layer. 5. substrate layer 15cm. 6. drainage layer 7cm (gravel). 7. polyethylene insulation layers 1.5cm. 8. relieved concrete to obtain a slope 2cm. 9. water insulation (asphalt) 1cm. 10. reinforced concrete slabs (roof) 10cm. farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 149 4. experimental work experimental work was carried out to examine the effect of the green roof and compare it with a traditional roof under influence of ambient air temperature, wind speed, and solar radiation, and test the effect of a green roof on reducing heat transfer inside the building. the model site was at adiwanyah city (latitude: 31.9868 and longitude: 44.9215), the engineering college campus, qadisiyah university. 5. results and discussion the experimental results allow evaluating and comparing the thermal behavior and energy consumption, for the two construction systems during summer period. the weather in diwaniyah is affected by the dry semitropical dry climate (desert), it is characterized by a hot dry climate in the summer. there is also a temperature fluctuation between day and night. the experiment was conducted in july and september of 2019. the experimental results include temperature measurements, wind speed, and solar radiation. 5.1. for period 18-21 july 2019 the boundary conditions for period 18-21 july 2019 include wind speed, ambient temperature, and solar radiation. figure 7. shows the ambient temperatures of the air and solar radiation, which have a massive effect on green roofs’ effectiveness. the higher the solar radiation is, the higher becomes the ambient air temperature. as for the figure 8. which shows the speed of the wind in this period. the higher the wind speed, the lower the temperature of the surrounding air, but significantly. figure 7. ambient temperature and solar radiation. figure 8. wind speed. figure 9. zone temperature. fig. 9 shows the temperature of the zone in the two rooms. the maximum temperature was 46.02 ° c for traditional roof and 38.6 °c for the green roof, we note that the zone temperature decreased by 7.42 °c in july. the decrease in temperature during the maximum solar radiation due to the effect of the green roof and the effect of the vegetation, which absorbs a large part of the solar radiation by shading. the process of evaporation that occurs in the growth substrate because it contains moisture, which decreases heat flow through the roof, thus reducing the temperature reaching that zone. while fig. 10 shows the temperature of the inner surface of the roof. results showed that the maximum temperature was 45.66 °c and 37.41 °c for the traditional roof and green roof respectively. it can be noted that the green roof has significantly decreased the maximum inner surface temperature by 8.25 °c. again, the green roof reduces the heat flow inside the roof due to the presence of vegetation that absorbs/reflects a large part of the solar radiation incident on the surface due to shading and transpiration. in addition to the evaporative cooling process due to the presence of moisture in the soil, the substrate also acts as an insulating layer, which reduces heat flow and thus lowers the internal roof temperature. therefore, a green roof has been used to reduce consumption of cooling energy during the summer and to request heating during the winter, as the green roof acts as an insulation layer. 0 200 400 600 800 1000 1200 0 5 10 15 20 25 30 35 40 45 50 1 6 :0 0 2 0 :0 3 0 :0 6 4 :0 9 8 :1 2 1 2 :1 5 1 6 :1 8 2 0 :2 1 0 :2 4 4 :2 7 8 :3 0 1 2 :3 3 1 6 :3 6 2 0 :3 9 0 :4 2 s o la r ra d ia ti o n w /m ^ 2 t e m p e ra tu re c d e g time t amb i w/m2 0 1 2 3 4 5 6 7 8 9 10 1 6 :0 0 1 9 :2 3 2 2 :4 6 2 :0 9 5 :3 2 8 :5 5 1 2 :1 8 1 5 :4 1 1 9 :0 4 2 2 :2 7 1 :5 0 5 :1 3 8 :3 6 1 1 :5 9 1 5 :2 2 1 8 :4 5 2 2 :0 8 1 :3 1 w in d s p e e d m /s time 0 5 10 15 20 25 30 35 40 45 50 1 6 :0 0 1 9 :2 3 2 2 :4 6 0 2 :0 9 0 5 :3 2 0 8 :5 5 1 2 :1 8 1 5 :4 1 1 9 :0 4 2 2 :2 7 0 1 :5 0 0 5 :1 3 0 8 :3 6 1 1 :5 9 1 5 :2 2 1 8 :4 5 2 2 :0 8 0 1 :3 1 t e m p e ra tu re c d e g time t with green t without green 150 farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 figure 10. roof internal surface temperature. gmklllll’;l; gggggggggg increasing wind speed. however, the trend of ambient air figure 11. the temperature of the external surface of the roof. in fig. 11 the maximum temperature of the external surface of the roof decreased by a rate of 7.46 °c, due to the presence of vegetation and the soil that acts as an insulating layer, thus reducing the heat flux of the roof. 5.2. for period 5-8 september 2019 the boundary conditions for period 5-8 september 2019 also include wind speed, ambient temperature, and solar radiation. fig. 12 shows that the ambient air temperature traces the solar radiation that occurred from sunrise to solar midday, after which a significant deviation in its behavior is indicated. it should be noted that the maximum ambient air temperature is around 43.18°c at 3:29 p.m., while the minimum ambient air temperature is 26.8°c at 6:08 a.m. the high ambient air temperature during the summer will affect green surfaces. also, fig. 12 shows the fluctuations in solar radiation value. figure 12. ambient temperature and solar radiation. figure 13. wind speed. the maximum solar radiation during the afternoon period is 876 w/m^2 at 12:44 pm, while the lowest solar radiation value reaches zero w/m^2 during the absence of sunlight. and fig. 13 shows that the wind speed has a limited effect on ambient temperature during the test period, where it decreases slightly with increasing wind speed. however, the trend of ambient air temperature continues to rise despite wind speed due to earth accumulating energy. fig. 14 shows the temperature of the zone in the two rooms. the maximum temperature was 46.4 ° c for traditional roof and 37.06 °c for the green roof at 3:24 p.m. the zone temperature decreased by 9.34 °c in september, because the green roof reduces the heat flux entering the model by absorbing a large part of the solar radiation by shading and thermal insulation in addition to evaporative cooling. 0 10 20 30 40 50 60 1 6 :0 0 1 9 :2 3 2 2 :4 6 2 :0 9 5 :3 2 8 :5 5 1 2 :1 8 1 5 :4 1 1 9 :0 4 2 2 :2 7 1 :5 0 5 :1 3 8 :3 6 1 1 :5 9 1 5 :2 2 1 8 :4 5 2 2 :0 8 1 :3 1 t e m p e ra tu re c d e g time t without green t with green 0 10 20 30 40 50 60 1 6 :0 0 1 9 :2 3 2 2 :4 6 2 :0 9 5 :3 2 8 :5 5 1 2 :1 8 1 5 :4 1 1 9 :0 4 2 2 :2 7 1 :5 0 5 :1 3 8 :3 6 1 1 :5 9 1 5 :2 2 1 8 :4 5 2 2 :0 8 1 :3 1 t e m p e ra tu re c d e g time t with green t without green 0 100 200 300 400 500 600 700 800 900 1000 0 5 10 15 20 25 30 35 40 45 50 1 5 :0 9 1 9 :2 2 2 3 :3 5 3 :4 8 8 :0 1 1 2 :1 4 1 6 :2 7 2 0 :4 0 0 :5 3 5 :0 6 9 :1 9 1 3 :3 2 1 7 :4 5 2 1 :5 8 2 :1 1 s o la r ra d ia ti o n w /m 2 t e m p e ra tu re c d e g time t amb i w/m2 0 2 4 6 8 10 12 14 1 5 :0 9 1 8 :5 2 2 2 :3 5 2 :1 8 6 :0 1 9 :4 4 1 3 :2 7 1 7 :1 0 2 0 :5 3 0 :3 6 4 :1 9 8 :0 2 1 1 :4 5 1 5 :2 8 1 9 :1 1 2 2 :5 4 2 :3 7 w in d s p e e d m ls time farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 151 figure 14. zone temperature. and fig. 15 shows the temperature of the inner surface of the roof. results showed that the maximum temperature was 46.97 °c and 36.42 °c for the traditional roof and green roof respectively at 3 p.m. it can be noted that the green roof has significantly decreased the maximum inner surface temperature by 10.55°c. the green roof reduces the heat flow inside the roof due to the presence of vegetation and the substrate, which acts as an insulating layer, thereby reducing the heat flux to the inside of the roof. figure 15. roof internal surface temperature. while figure 16. shows that temperature of the external roof surface. the results indicate that the maximum external surface temperature was 53.18 °c and 41.79 °c for traditional and green roofs (on vegetation layer), respectively. the maximum green roof surface temperature has decreased by 11.39 °c. the reason for this decrease is that: the vegetation reduces solar radiation penetration, external temperature, and relative humidity as it passes through the foliage in addition to that the substrate contains moisture and acts as an insulation layer, so decreases the temperature that reaches the external surface of the green roof. figure 16. the temperature of the external surface of the roof. 5.3. saving in electricity cost the value of cooling load was calculated from equation (1), and the assumption of the building used is a residential building and cooling control operates a half-day as well as it was assumed that the effect of the green layer is neglected due to the difficulty of calculating the thermal resistance of this layer and also that the results obtained as a result of the existence of this layer. also, the consumption category was chosen from the second category with average consumption (1501 300) kilowatt per hour at a price of 35 dinars, per unit [25]. to calculate the savings in the cost of electricity during the summer season, assuming that the summer season consists of four months. fig. 17 shows saving in electricity cost. table 2. saving in electricity for period 18-21 july 2019. saving in electricity cost dinar/ summer session saving in electricity cost dinar/ month saving in electricity cost dinar/ day cooling load (w) date (july 18-21) 426.88 106.7 3.55 8.47 st. roof 405.2 101.3 3.37 8.04 gr. roof table 3. saving in electricity for period 5-8 of september 2019. saving in electricity cost dinar/ summer session saving in electricity cost dinar/ month saving in electricity cost dinar/ day cooling load (w) date (september 5-8) 425.8 106.45 3.55 8.45 st. roof 310.46 77.6 2.59 6.16 gr. roof 0 10 20 30 40 50 60 1 5 :0 9 1 8 :4 0 2 2 :1 1 1 :4 2 5 :1 3 8 :4 4 1 2 :1 5 1 5 :4 6 1 9 :1 7 2 2 :4 8 2 :1 9 5 :5 0 9 :2 1 1 2 :5 2 1 6 :2 3 1 9 :5 4 2 3 :2 5 2 :5 6 t e m p e ra tu re c d e g time t without green t with green 0 10 20 30 40 50 60 1 5 :0 9 1 8 :4 0 2 2 :1 1 1 :4 2 5 :1 3 8 :4 4 1 2 :1 5 1 5 :4 6 1 9 :1 7 2 2 :4 8 2 :1 9 5 :5 0 9 :2 1 1 2 :5 2 1 6 :2 3 1 9 :5 4 2 3 :2 5 2 :5 6 t e m p e ra tu re c d e g time t with green t without green 0 5 10 15 20 25 30 35 40 45 50 1 5 :0 9 1 8 :4 0 2 2 :1 1 1 :4 2 5 :1 3 8 :4 4 1 2 :1 5 1 5 :4 6 1 9 :1 7 2 2 :4 8 2 :1 9 5 :5 0 9 :2 1 1 2 :5 2 1 6 :2 3 1 9 :5 4 2 3 :2 5 2 :5 6 t e m p e ra tu re c d e g time t with green t without green 152 farah abdul kadhum malika, alaa liaq hashem /al-qadisiyah journal for engineering sciences 13 (2020) 144–152 figure 17. saving in electricity cost for july and september 2019. 6. conclusion in this paper, experimental investigation is made to study the effect of the green roof to reduce the heat transfer to the interior of the building and compare it to the traditional roof. the results of this work are summarized as follows:  through the experimental results of july, we notice that the temperature of the zone decreased by 7.5 ° c. while the maximum temperature of the traditional internal roof surface is 45.66 ° c and 37.41 ° c for the green roof. as for the month of september, the temperature of the zone decreased by 9.34 ° c, the maximum temperature was 46.97 ° c and 36.42 ° c for the traditional roof and green roof respectively at 15:00 pm. it can be seen that the green roof has significantly reduced the maximum internal surface temperature by 10.55 ° c.  the cost of reducing the cooling load and saving electricity was 26.8% for september and 5.06% for july.  the performance of the green roof system depends largely on three factors, the geographical location of the building and the leaf area index, in addition to the depth of the growth substrate (soil). the higher the depth of the soil, the greater the rate of reduction in consumption due to the increase in the value of the insulation and the thermal mass.  the reduction in load by using green roof was 27.1% for september and 5.08% for july. references [1] the annual statistical report in iraq, electrical energy production, center for information and control. 2018. 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[20] a.b. besir, e. cuce, green roofs and facades: a comprehensive review, renewable and sustainable energy reviews 82 (2018) 915-939. [21] j. coma, g. pérez, c. solé, a. castell, l.f. cabeza, thermal assessment of extensive green roofs as passive tool for energy savings in buildings, renewable energy 85 (2016) 1106-1115. [22] ministry of construction and housing: republic of iraq., thermal insulation guide: iraqi construction guide, (first edition, 2013). [23] j.p. holman, j.p. holman, heat transfer, mcgraw-hill companies1976. [24] m.i. hasan, h.o. basher, a.o. shdhan, experimental investigation of phase change materials for insulation of residential buildings, sustainable cities and society 36 (2018) 42-58. [25] annual statistical report for the overal electrical production in iraq, iraq (2017). 0 50 100 150 200 250 300 350 400 450 july september e le ct ri ci ty c o st (d in a r/ su m m e r se ss io n ) data st. roof article al-qadisiyah journal for engineering sciences 15 (2022) 132–135 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hadeelalobaidi90@gmail.com ( hadeel a. alobaidi) https://doi.org/10.30772/qjes.v15i2.824 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. influence of heat aging on tensile test in rubber-epoxy composites hadeel a. alobaidi* and nabeel almuramady department of mechanical engineering, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 13 may 2022 received in revised form 10 june 2022 accepted 5 july 2022 keywords: heat aging natural rubber epoxy resin tensile test a b s t r a c t composite materials using natural rubber as the main matrix are popular these days because of the wide applications of rubber materials in modern industries. rubber materials also have damping properties, energy absorption, and exposure to continuous loads and different environmental conditions. in this research, the effect of temperatures on the rubber-epoxy composite with different ratios (0%, 10%, 20%, 30%, 40%, and 50%) of epoxy has been studied. where comparison was made between heat-aged and unaged samples using the tensile test. to know the effect of high temperatures on the rubber-epoxy composite, it was done in a heated oven at a temperature of 70◦c. the results obtained from the tensile test observed a decrease in tensile strength and elongation when exposed to thermal aging. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction natural rubber has been widely used in the twentieth century and that has led to a huge increase in its sophisticated applications. thus, the industrial rubber sector was resorted to in world war ii, because of its ideal characteristics such as flexibility, lightweight, resistance, deformation capacity, or vibration isolation. it was also used as a basic material in composite materials, in which natural rubber is blended with various additives to make it more suited for the applications for which it was designed [1-5]. rubber composites' mechanical characteristics are affected by temperature and time. where the crosslinking and chain disintegration are both caused by thermal aging. the expandability decreases and the modulus of the material increase due to the crosslinking. the unsaturated carbon-carbon double bonds in the backbone of rubbers make them sensitive to oxidative aging. this type of oxidative aging is generally aided by high temperatures [6, 7]. toughened epoxy has a popular addition in research because of its ability to boost composite strength. epoxy resins have a hard form, an anti-slip coating, minimal cure shrinkage and good electrical properties. also, its compatibility with a wide range of materials, dependability, and the ability to cure under adverse conditions. it is also employed as an adhesive in composites almuramady, et al. [8]. potting, building construction, chemical-resistant equipment, weathering, boats, and other applications, thus it has acquired widespread popularity in the industrial field over the last 20 years [9, 10]. the effect of temperature on rubber compounds was one of the important topics that many scientists touched upon, as the increase in the temperature of rubber leads to a loss of its ductility and ability to dampen and increase its hardness as a result of repeated use for a long time, which affects the life of the sample. among the characteristics that were affected by aging was the ability of the material to stretch and elongate and that will be addressed in this research [11-13]. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i2.824 http://creativecommons.org/licenses/by/4.0/ hadeel alobaidi and nabeel almuramady. /al-qadisiyah journal for engineering sciences 15 (2022) 132–135 133 2. experimental work 2.1. materials the practical side was implemented in several stages where natural rubber was used as a matrix material in this work, and (epoxy resin) and (carbon black) were used as reinforcing materials. first step: the natural rubber paste was prepared by adding (carbon black) only as a hardener with what is mentioned in table 1 below, where the work was done in the general company for tire and rubber industry in diwaniyah iraq. table 1. materials used in the preparation of rubber dough without epoxy. material occupation rubber rss1 basic material zinc oxide tonic stearic acid tonic sulfur vulcanization agent dcbs accelerator accelerated tbbs accelerator accelerated n₃₂₆ reinforcement filling n₁₁ₒ reinforcement filling renacit digestive substance struktol 40 ms homogenizing substance wax oxidation protection ippd oxidation protection escorez 1102 adhesive resorcinol melt adhesive pvi cathodic substance hmt adhesive second step: is to mix natural rubber with epoxy, where the epoxy is first prepared. the epoxy that was used in this work is sikadur-52 produced by sika egypt for construction chemicals and consists of two components of high grade, low viscosity (1000-250) mpa.s, yellow in color, density at 20°c is about 1.1 kg/l and has a mixing ratio of 2r:1h based on weight. at room temperature (25°c), the epoxy resin and the hardener were mixed manually in a ratio of 2r:1h. mixture has been mixed and moved continuously until it becomes homogeneous and air bubbles have been disappear, then it was added to the natural rubber in different proportions (0%, 10%, 20%, 30%, 40%, and 50%) of epoxy. 2.2. samples preparation after the dough preparation, it was placed in the rolling machine fig. 1a to make it a more homogeneous dough. equipment’s have been used to control the distance between the two rollers so that the distance ranges from the lowest distance of 2 mm to the highest distance of 8 mm, and the final thickness of the dough that got from the rolling machine was 3mm. then the dough has placed in the heat press fig. 1b by using special molds for testing, under ideal conditions (pressure of 3.5 mpa and temperature of 146 °c for a period ranging from 15 to 20 minutes) to obtain vulcanized composite rubber. a b figure 1. (a) the rolling machine; (b) heated press machine 2.3. tensile testing in order to prepare tensile specimens, a special mold has been used to obtain a composite material specimen with the required dimensions to fit with the tensile test device. the template which was used to obtain the tensile samples are shown in fig. 2 tensile test has been studied according to astm d638 − 14 type iv [14, 19]. figure 2. tensile test specimen according to astm d638 − 14 type iv. 134 hadeel alobaidi and nabeel almuramady. /al-qadisiyah journal for engineering sciences 15 (2022) 132–135 the tensile test was performed at room temperature in the laboratories of the university of babylon / college of materials, using a microcomputercontrolled electronic universal testing machine) of chinese origin, model (wdw-5e) that was controlled by a computer, shown in fig. 3. the force was applied (load control) at a speed of 100 mm / min until a failure of the sample was occurs and then the stress-strain curve was plotted. figure 3. tensile test device. 2.4. aging test some samples of dumbbells were taken and placed in an aging oven (o7e multi-cell aging oven) produced by wallace test equipment company according to astm d573-99 specification [15]. where the oven consists of 7 cells isolated from each other to prevent contamination of the knees with volatile materials [16-18]. the samples have been placed for 7 days at a temperature of 70 degrees celsius by means of an automatic timer and as in fig. 4. where the work was done in the general company for tire and rubber industry in diwaniyah iraq. to find out the effects of thermal aging on the rubber compound and the extent of its resistance to wear over time, a tensile test was conducted for the aged samples and compared with the tensile test for the original unaged samples. figure 4. the oven aging. 3. results and discussions the 24 tests of the successful tests have been conducted to calculate the tensile resistance of natural rubber composite mixed with epoxy resin with different ratios (0%, 10%, 20%, 30%, 40%, and 50%) of epoxy. where the results test for all the percentages were compared with the purely natural rubber sample. as shown in fig. 5, represents a graph of the true stressstrain curve of the rubber-epoxy compound. where a discrepancy was observed in the results between the different percentages of the rubberepoxy composite that was not aged by heat. where an increase in stress was observed as the percent of epoxy increased, and decrease in elongation when the epoxy ratio increased and this was due to the hardness property of epoxy, which increases the hardness of the composite, which makes it resistant to stress and elongation. figure 5. stress-strain curve. fig 6. represents the difference in tensile strength between the composites that have different percentages of epoxy (0%, 10%, 20%, 30%, 40%, and 50 %) of the samples that were tested in the tensile testing device without aging and the samples that were tested in the tensile device and were aged in an air oven. where we notice a discrepancy in the results, where the results are divided into two parts, the first part, in which the tensile strength and elongation are in a descending state, i.e. decreasing with the increase in the percentage of epoxy. as for the second part, there is an increase in tensile strength with a decrease in elongation when the ratio of epoxy in the composite increases for the first test (without aging). as for the second test (samples that were previously aging), noticed a discrepancy in the results, as the effect of the rubber-epoxy composite, was observed in temperature as in figs 6 and 7, where a decrease in the values of stress resistance and elongation when the ratios of epoxy resin increase more than the test the first. but when the epoxy ratios were increased to 40% and 50%, there was an increase in the stress resistance for the samples that were aging, however less than in the first test. this change was attributed to the effect of increasing the amount of epoxy in the composite and also to the effect of the high temperatures on the composite, which affected it was viscous properties and decreased and hardness slightly. -2 0 2 4 6 8 10 12 14 16 18 0 0.5 1 1.5 2 2.5 3 s tr e ss ( m p a ) strain stress-strain curve 0% 10% 20% 30% 40% 50% hadeel alobaidi and nabeel almuramady. /al-qadisiyah journal for engineering sciences 15 (2022) 132–135 135 figure 6. effect the heat aging on the max tensile strength. figure 6. effect the heat aging on the elongation. 4. conclusion in this research, the effect of temperatures on the rubber-epoxy compound with different epoxy resin ratios (0%, 10%, 20%, 30%, 40%, and 50%) were studied. the original samples were compared with the heat-aged samples by conducting a tensile test for them. a decrease in the tensile strength and elongation of the samples was indicated in the beginning by an increase in the percentage of epoxy, then it will be increased with an increase in the epoxy ratio. also, a discrepancy was observed in the results with the heataged samples due to the added quantities of epoxy rubber and it was the effect of high temperature. and due to the rubber being also affected by heat for periods and loss of flexibility, ali [8]. references [1] ikeda, y., kato, a., kohjiya, s. and nakajima, y., 2018. rubber science. springer: berlin/heidelberg, germany. [2] kohjiya, s., 2015. natural rubber. smithers rapra. [3] almuramady, n., borodich, f.m., goryacheva, i.g. and torskaya, e.v., 2019. damage of functionalized self-assembly monomolecular layers applied to silicon microgear mems. tribology international, 129, pp.202-213. [4] wang, x.l., liao, m.y., xu, y. and liu, x.a., 2018. fatigue crack propagation characteristics of rubbery materials under variable amplitude loading. results in physics, 10, pp.233-240. [5] zarrin-ghalami, t., 2013. fatigue life prediction and modeling of elastomeric components. the university of toledo. [6] dal, h. and kaliske, m., 2009. a micro-continuum-mechanical material model for failure of rubber-like materials: application to ageing-induced fracturing. journal of the mechanics and physics of solids, 57(8), pp.1340-1356. [7] hu, x., li, y., liu, x. and luo, w., 2013. experimental studies of thermal aging effects on the tensile and tearing fracture behavior of carbon black filled rubbers. icf13, pp.1-5. [8] almuramady, n. and borodich, f.m., 2017. adhesive contact between silicon based mems tooth surfaces modelled by the multiscale multi-block model. international journal of advances on automotive and technology. doi:10.15659/ijaat.17.04.523 [9] billmeyer, f.w., 1984. textbook of polymer science. john wiley & sons. [10] almuramady, n. mechanical properties of composites using natural rubber with epoxy resin, msc thesis.university of al-nahrain, 2007. [11] brown, r., 2006. physical testing of rubber. springer science & business media. [12] mandel, j., roth, f.l., steel, m.n. and stiehler, r.d., 1959. measurement of the aging of rubber vulcanizates. j. res. natl. bur. stand., sect. c, 63, pp.141 -145. [13] ali, a., hosseini, m. and sahari, b.b., 2010. heat-aging effects on tensile properties of vulcanized natural rubber. international review of mechanical engineering, 4(4), pp.422-424. [14] standard test method for tensile properties of plastics, designation: d638 − 14. [15] standard test method for rubber—deterioration in an air oven1, designation: d 573 – 99 [16] https://www.wallaceinstruments.com/products/laboratory-and-ageingovens/o7e-multi-cell-ageing-oven [17] mosa, m.h., almuramady, n. and hussein, k., 2020. numerical investigation to optimizing the design of helical compression spring by using hollow shaft. journal of green engineering, 10, pp.3832-3843. [18] kadhimm zarzoor, a., almuramady, n. and hussein, e.s., 2018. stress analysis for spur gears using solid works simulation. int. j. mech. eng. technol, 259, pp.927-936. [19] https://www.alibaba.com/product-detail/astm-d412-rubber-plasticdumbbell-tensile_60827990137.html 0 2 4 6 8 10 12 14 16 18 0% 10% 20% 30% 40% 50% m a x . s tr e ss m p a epoxy ratio max. tensile strength without aging with aging 0 100 200 300 400 500 600 700 800 900 0% 10% 20% 30% 40% 50% p re c e n ta g e e lo n g a ti o n % epoxy ratio precentage elongation at max. load % without aging with aging https://www.alibaba.com/product-detail/astm-d412-rubber-plastic-dumbbell-tensile_60827990137.html https://www.alibaba.com/product-detail/astm-d412-rubber-plastic-dumbbell-tensile_60827990137.html article al-qadisiyah journal for engineering sciences 14 (2021) 117–122 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hayderalmumen@gmail.com (haider al-mumen) https://doi.org/10.30772/qjes.v14i2.753 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. flexible field effect transistor construction techniques, a brief review haider al-mumen department of electrical engineering, university of babylon a r t i c l e i n f o article history: received 11 may 2021 received in revised form 21 june 2021 accepted 22 june 2021 keywords: fabrication flexible electronics semiconductor field effect transistor a b s t r a c t since the flexible field effect transistor (f-fet) is the building block of any sophisticated electronic circuit, particularly in the area of wearable electronics and biomedical sensors, it has drawn a lot of attention recently. it is usually fabricated using stretchable semiconductors over polymeric substrates. this paper displays a brief overview of the current fabrication techniques of the f-fet, specifically in terms of the type of substrates and nano semiconductor technologies. as for the applications, flexible devices such as graphene, carbon nanotubes and nanoparticles seem to be a candidate for the future flexible devices due to their excitant electronic and stretchable characteristics. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction 1.1 f-fet structure typically, f-fet consists of a source, drain, and gate. it constricts on an insulating substrate. the source and drain are deposited on a semiconductor and connected to an external power supply through conductive electrodes, usually gold, copper, or silver. the gate of the fet is usually fabricated either on the top or the bottom of the substrate, that’s why the fet structure called the top or bottom gate (fig. 1 ). figure 1 fet structure; (a) with a bottom gate; (b) with a top gate; (c) f-fet with a flexible substrate; (d) electronics on a fexible substrate basically, the charge carriers flow through the fet under the control of the applied gate voltage. the relationship between vgs and ids is: ids= b c d http://qu.edu.iq/ mailto:hayderalmumen@gmail.com https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 118 haider al-mumen /al-qadisiyah journal for engineering sciences 14 (2021) 117–122 µ(wc/2l) (vgs-vt) 2 , where ids is the current that is flowing from drain to source, c is the insulator capacitance, vt is the threshold voltage, w is the width of the channel, and l is its length schneider et al. [1]. 1.2. effect of bending on f-fet characteristics based on reported articles [2, 3], bending an f-fet causes two potential effects on the f-fet properties. first, it affects the i-v characteristic. second, it affects the electron mobility of the f-fet. as illustrated in fig. 2, the effect of bending is also depending on whether the bending is upward or downward. remarkable differences have been seen in the electron mobility and the i-v curve between the downward bending (fig. 2-a) and upward bending (fig. 2-b). however, bending in the same direction leads to a very slightly changing in the f-fet properties. figure 2(a) schematic of downward bending of f-fet on pet substrate and corresponding i-v curve and electron mobility. (b) schematic of upward bending of f-fet on pet substrate and corresponding i-v curve and electron mobility [4]. 2. types of flexible substrates the material of a substrate decides the mechanical properties such as the strain and bending angle of the fabricated device. this is why the first thing that one needs to think about is substrate flexibility. the strain of a substrate is a function of its thickness, young’s modulus, and the type of the deposited layers upon the substrate. the strain can be calculated by yin et al. [5]: s= (𝒕𝑳+𝒕𝒔)(𝟏+ 𝟐𝒕𝑳 𝒕𝒔 + 𝒀𝑳× 𝒕𝑳 𝟐 𝒀𝒔×𝒕𝒔 𝟐 ) 𝟐𝑹+(𝟏+ 𝒕𝑳 𝒕𝒔 )(𝟏+ 𝒀𝑳×𝒕𝑳 𝒀𝒔×𝒕𝒔 ) where tl and ts are the thicknesses of the layer and the substrate respectively. while ys and yl are young’s modulus of the substrate and the layer respectively and r is the radius after bending. it should be mentioned that the conductivity of the device is dimension dependent, which could be changed with bending or stretching [5, 6]. 2.1. polyethylene terephthalate (pet)substrate basically, pet is a polyester family. depending on the thickness, pet could be rigid or flexible. it is lightweight, low cost, thermally stable, and moisture resistant bach et al. [7]. pet has young modulus of 2800-3100 mpa, dielectric constant of 60 kv/mm, and a melting point of around 250 0c faraj et al. [8]. it has been used in the design of flexible substrates for several applications such as flexible antennas [9, 10], biosensors[11, 12] wearable sensors gao et al. [13], and flexible electronics [14-16]. due to its nice optical properties (optical transmission of 85% ) and flexible under bending conditions macdonald [17] , pet becomes a candidate for flexible displays. optimal printed thickness and spacing for electronic application and also the thermal operation of the pet substrate have been reported riheen et al. [16], it was proved that the optimal spacing of inkjet printing for electronic application is around 20 µm and thermally durable at 120 0c. fig. 3-a shows a photo image of the pet, while fig. (3-b) is the afm image of the pet, it shows that the mean square of the surface roughness, which is about 13.5 nm [17]. figure 3(a) pet sheet (b) surface morphology of pet [17]. 2.2 polydimethyl siloxane (pdms) substrate pdms has been used as a flexible substrate due to its transparency, tailoring, chemical stability, and flexibility. in addition, it is easy to construct with the desired thickness qi et al. [18]. it has a young modulus of 1.4 mpa and dialectic strength of 27 kv/mm. these properties make b a b a haider al-mumen /al-qadisiyah journal for engineering sciences 14 (2021) 117–122 119 ` pdms used in microfluidics and electronics devices [18, 19]. furthermore, pdms is a biocompatible material, meaning similar to the human tissue, this makes it favorable in the construction of biosensors victor et al. [20]. fig. 4 shows a photographic image of a pdms layer. figure 4 flexible pdms substrate. 2.3. polyimide substrate polyimide is another interesting flexible polymeric material that has been used as a flexible substrate. in fact, multiple properties made polyimide an excellent choice such as flexibility, light-weight, low cost, relatively high operating temperature (up to 400 0c) and moisture resistance, young modulus of 4 gpa and a dielectric constant of 3. it has been used as a flexible substrate in many applications, for example, solar caballero et al. [21] cell, flexible printed circuits wang et al. [22], biomedical probes and wearable devices[23, 24]. fig. 5-a shows one of the applications of polyimide in biomedical probes. fig. (s-b) is the afm image of the polyimide, it shows the surface roughness is 22.52 nm, which is accepted for many applications. figure 5(a) bio-medical probe with a flexible polyimide substrate (b) afm image of a polyimide sheet with 22.52 nm surface roughness [25, 26]. 3. type of flexible semiconductor materials for f-fet 3.1. carbone nanotube (cnt) cnt has been used for several applications due to its excellent electronic and mechanical characteristics. high electron mobility, (26)×104 cm 2 /(v ×s), high stable current of 109 a/cm2, and high electrical conductivity (106 to 107 s/m ) mora et al. [27] makes cnt a promising for the design of highspeed f-fet [28-31]. it has also been used as a sensor, such as humidity and piezoelectric sensors [32-35]. additionally, the cnt’s mechanical properties have been studied and young's modulus was calculated to be on the order of 1tpa and tensile strength of cnt-polymer composite of 11-63 gpa arash et al. [36]. these exceptional properties made it compatible with the applications of flexible devices esawi et al. [37]. cnts can be deposited on a flexible substrate using spray coating. this method is the the simplest, low cost, and reliable method abdelhalim et al. [38]. 3.2. 2d materials graphene is a good example 2d material, a hexagonal structure (fig. 6), was invented by geim and his group using mechanical exfoliation [39, 40]. since the invention of graphene, many research groups have worked on it to investigate its properties and potential applications. basically, graphene has a lot of amazing electrical characteristic, example of high charge mobility (200 cm2/v×s) bolotin et al. [41], excellent mechanical characteristic (young modulus of 1 tpa), and nice thermal conductivity (3500w/mk to 5000w/mk) hu et al. [42]. therefore, graphene is nominated for future sensors and electronics [28, 43-49]. s. park et al. has fabricated a f-fet that has 95 ghz cutoff frequency park et al. [50]. while f. lui and his group constructed a f-fet with a large flexible area liu et al. [51]. graphene can be grown directly of on a flexible substrate by plasma enhanced chemical vapor deposition (pe-cvd) lee et al. [52]. whereas the simplest method for graphene deposition on the flexible substrate is by transfer method. in this method, a cvd graphene is grown on metal such as copper then a thin film of poly(methyl methacrylate( pmma) polymer, the e-beam resist, is deposited on graphene. then the metal etched. the pmma/graphene layers is transferred to a flexible substrate. finally, the pmma is dissolved by a solvent martins et al. [53]. figure 6scanning tunneling microscope (stm) image of a graphene sheet shows its hexagonal structure [54]. a b 120 haider al-mumen /al-qadisiyah journal for engineering sciences 14 (2021) 117–122 3.3. zinc oxide (zno) recent studies of zno indicated a lot of interesting properties that make it durable for many applications. the wide bandgap of ~3.4 ev, and the young modulus of 64-144 gpa, makes it applicable for flexible transistors and sensors [55, 56]. furthermore, since doping zno was successfully doped, then both n-type and p-type semiconductors can be constructed. this led to the ability of fabrication not only transistors but also logic gates. on the other hand, the most common method for growing zno on a flexible substrate are the inkjet printing method ko et al. [57], physical vapor deposition (pvd) kumar et al. [58], and hydrothermal baruah and dutta [59]. 3.4. organic semiconductors originally, organic materials, which are hydro-carbonic materials, have been used as an insulator in the microfabrication process. however, the conductivity of the organic materials was successfully modified to be close to that of semiconductors and metals after exposure to bromine, iodine, or chlorine [48, 60]. this led to the invention of the conductive polymers. these polymers have interesting electrical, optical, as well as their plastic and flexible, properties. several research groups [61-63] were used organic semiconductors in the design of f-fet as it is cheap and flexible. but bottle neck is that it is relatively slow carrier mobility that makes the f-fet slow. however, growing single-crystal organic semiconductor li et al. [64] improved the electron mobility with an average of 5.2±2.1 cm2/vs compared to 1.5 cm2/vs of the regular organic semiconductor. . this made it comparable to the conventional semiconductor transistors. fig. 7 displays a flexible organic transistors. figure 7photographic image of organic transistors [65] 4. significant applications of flexible electronics recently, the trend towards rubber electronics has become significant due to the presence of many applications and the emergence of modern technologies. for example, in the medical field, a group of rubber sensors has appeared, which are used in the field of optogenetics, through which brain signals are read. this technology is considered one of the promising technologies that will open the door wide towards a new generation of medical devices. energy scavenging is another application in the field of stretch electronics. this field includes the manufacture of stretchable rf antennas with its electronics in a flexible substrate. this antenna is called a patch antenna, which is a lowcost and simple structure. such technology can be used in wearable devices that are used to collect energy from the environment. this technique probably going to be the building block for future powerless portable devices. 5. conclusion the progress in the f-fet to date is a result of works in multiple directions. these directions can be categorized into materials of a flexible substrate and the type of a semiconductor. as for the semiconductor materials most research groups are currently working on nano and organic semiconductors. in fact, the field of flexibility seems to be promising due to many potential applications particularly in medical instruments and healthcare. this paper has made an attempt to summarize the fabrication methods and materials that probably help upcoming research to enter this field. nano flexible devices such graphene. , carbon nanotube and nanoparticles seem to be candidate for future electronics as they have remarkable properties particularly its electronic and mechanical properties. references [1] m. c. schneider and c. galup-montoro, cmos analog design using all-region mosfet modeling: cambridge university press, 2010. 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[65] h. matsui, y. takeda, and s. tokito, "flexible and printed organic transistors: from materials to integrated circuits," organic electronics, vol. 75, p. 105432, 2019. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٩ finding thermal distribution in the casting of alalloy by simulation using fdm. abstract the object is to get simulated observation of the solidification front movement inside casting, which was extracted from theoretical simulation of the solidification process, in the prediction of shrinkage cavities locations in the final ingots. a (fortran) program was developed using the finite difference method. several factors were taken into consideration in this system, such as the variation of liquid and solid volume fractions during solidification, changing the thermophysical properties of the cast metal with changing metal state and temperature. also, the latent heat was introduced as an isolated source term to the mentioned equation. the verification of the system efficiency was achieved by the comparison between the cavity location in theoretical and real casting. there was a good agreement. finally, the simulated cooling curves of selected points inside the casting were studied. key words: casting, simulation, solidification, thermal distribution, shrinkage ��5آ� *b %�اري�ا � �مإ!��د ا���ز!�� ت��<1ام �k!'� ا���و�8 ��ا��� ا��%�آ�ة ��أ� ا��%1دة ا�<=>� x!ك أو ���ة t� &'��ف -^ ا�s�g ه� ا���tل q�ا)p)�أ( ��� � دا�* ا��,�gآ� -^ �sل ��'+� -��آ�ة �t �� ���'+� ا��� ا�� �a� ام��� .�g��g#�' ��1اl) ا�$ �ات �8 ا��,�gآ�ت ا�#k�q+� ، )��ر@ ان(�1��<cا t#1 تmا-* أ����ة �: ر �8 هmا ا�#�tم -#��q ه#�ك ��� وا��a+� ��8 ا�<��اص ا�� ار��� �'��,�gآ� -�) @a+� �4��� ا�����ن ودر!�� ، ا��a+ �8 ا�6, ا�� � 8�k�,'* وا��e't إ2#��ء ا�� ��� ا����q -^ آ$���k ا�#��tم @�? ���1ر��� ا�#���vk ا�#t . آm�y ��ن ا�� ارة ا��6-#� ��� ��د @? إ�q���w �'���د�� �w^ ا�#�tم . ا�� ارة �، -��) ا����,�gآ� ا���+�+�����+! q1���)@ آ���ن ه#���ك s��+4 . *ط دا�������#� ���� t� �'t����,��ا ���� g��ت ا���+#�#^�������� و@��? درا���� .ا��,�gآ� ass.pro. dr. adnan sh. jabur college of engineering university of basrah heider. y. thamir college of engineering university of al-qadisiya ���ن g! 8>�u . د� ���#q�آ'+� ا !�-�� ا�tg ة �ر ��� �2+4 ���#q�آ'+� ا ��د�+�ا�!�-�� al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٠ literature review since last three decades using of programming entered to casting filed (design and analyses). the available of high speed processors helped in developing a new programs and packages used in this purpose. niyama et al (1981), made a mapping of the calculated heat gradient at the time of solidification of large steel casting, and they found that it was a powerful tool for predicating shrinkage porosities, particularly those occurring along the centerline of the casting. they have found that the porosities were formed in those areas where the g at the time of solidification was to be below 2-3 c/cm. balcar et al(2007), used (magma) software to model the casting and solidification of ingots for open-die forgings to fined directional solidification, grain size, chemical heterogeneity and discontinuities. vassiliou et al (2008), obtained realistic results from casting simulation programs to the enhancement of process of centrifugal casting. charach and zarmy (1991), proposed an analytical solution for planar solidification in a finite thickness slab by transforming the problem to one without the density change. huang and akay(1995), studied a heat transfer phenomena at cast-mold interface. trovant and argyropoulos(1996), proposed an algorithm to account for shrinkage and consequently determine the shrinkage profile resulting from phase and density change. campell and wright(1997), improved using of cooling fins by simulation of solidification and calculate solidification time. qasssim daws(1997), developed a program for steel castings solidification and derived an equation to calculate a less length of runner. yapping (1999), simulated a continuous casting for large aluminum castings by finite element method to locate hot spot and analyze thermal stresses. bounds et. al.(2000), proposed a model for macro defect predictions based on the coupling of the free-surface flow, heat transfer, and solidification. experimental procedure of work 1materials and instruments the materials, tools and instruments which are used in the present work are: 1one kilogram of aluminum alloy of type lm13 with a standard chemical composition contained in table (1). 2an alumina crucible. 3a wood pattern of the ingot with dimensions as shown in figure (1). 4a sand mold with a dimensions (30 × 40 × 40 cm). 5a gas furnace for melting. 6degasser of type (c2cl6), for the melt degassing. 7k-type thermocouple with a digital thermometer. 2 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨١ casting procedure the melting procedure of the alloy was accomplished by using the gas furnace. after the molten alloy reaches (620 o c) it was degassed, then the crucible is removed from the furnace, and preparing for pouring at (610 o c). the temperature control was achieved by using the thermocouple. 3cavities localization after the solidification is completed, the sand mold is broken, and the ingot was left to cool. then it was sectioned longitudinally through the two perpendiculars mid planes. then other sections were done to precisely identify the cavities extension, figure (2). 4numerical modeling 1assumptions made the following assumptions were made for the formulation of the problem; 1. mold is filled instantaneously. 2. phase transformation proceeds in one direction: liquid to solid. 3.no convection is present in the liquid metal. 4. initially the molten metal is at a uniform temperature. 2solid fraction and latent heat the latent heat was added to the model as a source term. the following processing shows this treatment(xue,1991): • + ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ q z t y t x t k t t c )()(. 2 2 2 2 2 2 ρ ……….1 t f l z t y t x t k t t c s ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ ..)()(. 2 2 2 2 2 2 ρρ …………..2 t t t f t f ss ∂ ∂ ∂ ∂ = ∂ ∂ . …………..3 t t t f l z t y t x t k t t c s ∂ ∂ ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ ...)()(. 2 2 2 2 2 2 ρρ …..………4 )(...)(. 2 2 2 2 2 2 z t y t x t k t t t f l t t c s ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ ∂ ∂ − ∂ ∂ ρρ ………….5 )( . ).1( 2 2 2 2 2 2 z t y t x t c k t f c l t t s ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ − ∂ ∂ ρ ……………6 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٢ for simplicity, it was supposed that solidification process is linear with decreasing temperature, so the rate: t f s ∂ ∂ can be approximated as: solidusliquidus soliduss tt tt t f − − −= ∂ ∂ 1 , and the above equation becomes: )]).(1(1[ 1 )( . 2 2 2 2 2 2 c l tt ttz t y t x t c k t t solidusliquidus solidus − − −− ∂ ∂ + ∂ ∂ + ∂ ∂ = ∂ ∂ ρ …………..7 5system thermophysical properties the thermophysical data can be classified into three classes: temperatures which are used to control the display options, the thermal properties which are used to solve the energy equation; and the phase change properties which are used to convert the specific heat content of each cell to its representative temperature. 1thermophysical properties of the sand the thermal properties of the mold sand remain constant during casting process. they are(mills,2002): initial temperature, t = o 30 c density, ρ = 1500 kg/m 3 thermal conductivity, k = 0.5 w/m .c specific heat, c = 666 j/kg.c 2thermophysical properties of the alloy the aluminum alloy properties were changed with respect to state of casting (liquid or solid), these are thermal conductivity and heat capacity, while the density value was changed with respect to temperature change using a linear relationships at liquid state and solid state. (mills,2002) 1liquid state temperature of pouring, tp = o 610 c liquids temperature, tl = o 573 c density, ρ= 2482-0.27 × (ttl) kg/m 3 ………..8 thermal conductivity, k = 64 w/m .c specific heat, c = 1200 j/kg.c 2solid state (mills,2002) solidus temperature, ts = o 542 c density, ρ = 2690-0.19 × (t-25) kg/m 3 ……….9 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٣ thermal conductivity, k = 160 w/m .c specific heat, c = 1000 j/kg.c 3mushy state in the mushy state any thermophysical property is treated according to rule of mixture, where required property (p) can be calculated at temperature t from equation 10, where fs (t) is the solid fraction at t and ps and pl are values of the property at the solid and the liquid state, respectively.[11] pt =fs (t ) ps +(lfs (t ))pl ……………10 latent heat, l = 489000 j/kg mushy temperature interval, jt = 31 6finite difference formulation according to the method of finite difference formulation the differential equation can be formulated as:             ∆ +− + ∆ +− − − −− ∆ += −+−+∆+ 2 11 2 11 ,,,, )( 2 )( 2 .( )]).(1(1[ [ y ttt x ttt c l tt tt t tt t y t y t y t x t x t x solidusliquidus solidus t zyx tt zyx α )] )( 2 2 11 z ttt t z t z t z ∆ +− + −+ where: c k .ρ α = , which is called the thermal diffusivity. 7casting system meshing the casting system (mold and ingot) were divided into 384000 cubes with a dimensions of (0.5 × 0.5 × 0.5 cm). the ingot consists of (1680) cubes, (figure 3). to clarify the solidification front by contours progress, the shape of ingot was sectioned into six layers (a, b, c, d, e, and f) with (0.5 cm) thickness, each layer consists of (280) meshes, (figure 4). the solidification contours are drawn on these slides. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٤ 8computer working 1time-step the time-step can either be defined by the user, or calculated by the euler stability law. the timestep used in program is (0.05 sec), and the total steps are (12000) steps, that means the total time of program is (600) seconds. 2programming using the fortran language (fortran power station ©1995) the program was made to use in this work to apply analytical solutions for each mesh in the system (mold and cast) to solve equations which are related to the case. the program deals with each mesh as is it sand or cast? then with the cast as is it liquid, solid, or mushy? then gives each case its specified properties but with mushy state it calculates the solid fraction and adds the latent heat of solidification to heat transfer equation with respect to solid fraction. finally the program print results at all time steps. results and discussion 1-simulation verification figure (5) contains a photograph of ingot slices with a simulated cavity prediction at one of the final stages for comparison and to verify the system efficiency in identifying the shrinkage cavities locations. from this comparison , it was found that the simulation coincides approximately with real casting in the allocation of the shrinkage cavity through x-axis and its deviation far to the fin near to the other side. this was explained by the chilling effect of the fin at the solid state . but the real cavity appeared divided into two parts. this may be due to the bad mold preparation and uneven ingot thickness. also, the simulation succeeded in the cavity prediction through y-axis, so the cavity is symmetric in this axis. on the other hand, the cavity simulation did not coincide with real casting through z-axis because the real cavity deviated to the bottom part of the ingot, while it is symmetric in simulation. this is due to ignoring the effect of the sprue which was attached to the lower part of the ingot by a gate which partially played a role of feeder, consequently pulling the cavity down. 2simulation of solidification only the solidification front movement of the three layers a ,b, and c will be studied in this paragraph because the ingot was considered symmetric through z-axis , so that the solidification mechanism in these layers is same as that of d ,e , and f layers . the three states of metal were defined by three colors. the red defined the full liquid state (higher than 573 o c), the yellow defined the mushy (liquid + solid) state (between 573 and 542 o c), and the blue defined the full solid state (lower than 542 c). the most important indications which can be summarized from the simulation stages (figure 6) are: al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٥ -at second (3) after pouring, the transformation from liquid to mushy state , initiated at the layer (a) in the first two cubes at the fin edge toward the other side in the x-direction, while this transformation in (b and c) layers occurred in a thickness of one cube in x-direction .this change continued at second (4) and the next time with different speeds depending on the distance between the layer and the lower surface . the solidification starting at the fin edge is an expected behavior because it has a high area/volume fraction. -at second (4), the solidification also started at the four corners of ingot. this event occurred at second (7) for (b) and (c) layers. -at second (10), the transformations of the fin and the surrounding of ingot for three layers were completed. -at second (14), the transformation of layer (a) was completed and the other layers continued changing. -at second (18), the liquid/mushy change for three layers was completed. -from seconds (18) to (85.1), it was indicated that, the metal remained for a long time at the mushy state. this was an expected behavior, because the cooling rates decreased at the solidification range due to the evolution of the latent heat. -when watching the liquid/mushy changing through 4 , 7 , 10 , and 14 seconds, it was noted that the mushy region was located at the center of ingot ,which means that there is no chilling effect on the fin because the liquid and mushy states have low conductivity . -at second (85.1), the mushy/solid change started at the fin edge with the same differential in speed between the three layers . -at second (429.05), the enclosing of the solidification loops in layers (b) and (c) completed. -the most important indication was that, the cavity position deviated from the center of ingot toward the other side of fin .this can be attributed to the role of the fin as a chiller due to its high thermal conductivity. 3cooling curves when the comparison between the cooling curves of points 1 and 2 (figures 7 and 8) were made, it was found that the curve of point 2 showed a steep change in slope after solidification completion, while the curve of point 1 had a gradual transition which can be explained by the heat evolution from the solidification near the fin .generally, both two cubes had a long time of solidification due to the high heat content of the adjacent liquid ingot. points 3, 4, and 5 showed high cooling rates during solidification and a short period of solidification. these were due to the fin nature of thinning and low heat content. also appeared, the effect of the heat content of the ingot, on the curve of point 5 after solidification, in decreasing the slope (concave). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٦ between the internal points ( 6, 7, and 8) ,point 6 has highest cooling rate during solidification , and this is attributed to the effect of near fin which play the role of chiller after changing to solid . this effect decreased with points 7 and then 8 according to the distance between them and the fin. conclusions and suggestions • conclusions from the present work, the most important conclusions are 1the identification of the shrinkage cavities locations can be accomplished by drawing the solidification contours. the appearance of a closed loop in the solidification time contours is the criterion for this type of shrinkage. 2the difference of the thermal properties between liquid and solid give an influence to change the whole solidification behavior and then the location and extension of shrinkage cavity. • suggestions the main suggestions for future work are: 1. the development of the system to predict the cavities extension. 2. addition of the effect of the pouring system such as sprue and gate to system. references 1. 1e. niyama, t. uchida, m. morikawa and s. saito, "predicting shrinkage in large steel castings from temperature gradient calculations", afs int. cast metals journal, vol 6, pp 16-22, 1981. 2. 2martin.l. balcar, "modelling of thr solidification process and the chemical heterogenity of a 26nicrmov115 steel ingot "materials and technology, vol 41, pp 139–144, 2007. 3. 3a. n. vassiliou"investigation of centrifugal casting conditions influence on part quality" 3rd icmen,pp 347-356, 2008. 4. 4c. charach and y. zarmi, "planar solidification in a finite slab; effect of droplet impact", j. appl. phys. vol.70, pp. 6687-6693, 1991 5. 5huang.h, gurdogan.o, akay.h.u "thermal transport phenomena in metalcasting" simulation afs transaction 95 afs usa 1995 pp 243-246 6. 6m. trovany and s. a. argyropouos, "mathematical modeling and experimental measurement of shrinkage in the casting of metals", canadian metallurgical quarterly, vol.35, pp 77-84, 1996. 7. 7wright .t.c, campell.j , "enhanced solidification rate in casting by the use of cooling fins", afs transaction ,vol .104 ,afs usa 1997.pp.639-644. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٧ 8. 8daws.q, "computer simulation in mould design ", ph.d., university of baghdad, college of engineering, iraq, 1997 pp32 9. 9yaping.wu ''numerical of direct – chill casting of aluminum ingot'', ph.d, west virginia university, college of engineering and mineral, 1999. 10. 10s. bounds, g. moran, k. periclerous, m. cross, and t.n. croft: metall. mater. trans. , b, vol 31b, pp.515-527, 2000. 11. 11kenneth c mills, "recommended values of thermophysical properties for selected commercial alloys". woodhead publishing limited: cambridge england 2002. 12. 12x. xue, "modelling and simulation of fluid flow and heat transfer in mold filling". phd thesis, technical university of denmark (1991). 13. 13j. gerin sylvia, "cast metals technology", addison-wesley publishing company, inc. usa 1972. figure (1) dimensions of the ingot in (cm) figure (2) the cavities al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٨ figure (2) the cavities (a) (b) (c) figure (3) ingot meshing, a-isometric b-top view, c-side view cm figure.4. side view of casting sectioned to layers, a, b, c, d, e and f al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٨٩ figure (5) comparison of photograph of an ingot slices with a simulated cavity prediction at time (3) seconds liquid mushy solid figure (6) the solidification simulation steps(continue.) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٩٠ figure (6) the solidification simulation steps(continue.) c b at time (10) seconds c b a a at time (85.1) seconds c b a al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٩١ at time (429.05) seconds c b a p4 p5 p1 p2 p8 p7 p6 p3 c figure (7) selected points in slice (c) figure (6) the solidification simulation steps. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٩٢ p1 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x 0.05 seconds t e m p e ra tu re c p2 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x0.05 seconds t e m p e ra tu re c p3 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x0.05 seconds t e m p e ra tu re c p4 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x0.05 seconds t e m p e ra tu re c figure (8) the cooling curves of selected points in the casting (in -clayer) continue al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٩٣ p5 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x0.05 seconds t e m p e ra tu re c p6 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x0.05 seconds t e m p e ra tu re c p7 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x 0.05 seconds t e m p e ra tu re c p8 0 100 200 300 400 500 600 700 0 2000 4000 6000 8000 10000 12000 14000 time x0.05 seconds t e m p e ra tu re c figure (8) the cooling curves of selected points in the casting (in -clayer) article al-qadisiyah journal for engineering sciences 13 (2020) 022–030 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0) 770 554 5252. e-mail address: mohammed.ali@qu.edu.iq (mohammed ali mutar) https://doi.org/10.30772/qjes.v13i1.646 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. synthesis and characterization of new dental composite for dentistry based on unsaturated monomers and nano-fillers by photopolymerization mahdi saleh mahdi a*, mohammed ali mutar a a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 03 october 2019 received in revised form 06 january 2020 accepted 23 january 2020 keywords: dental composite nano fillers a b s t r a c t in this study, dental nano-composite specimens were prepared by dispersion of various amounts of nanosized fillers (ha, zro2, and sio2) in a monomer system containing 60% bis-gma and 40% tegdma. 2,2 propyl bis-phenyl glycidyldimethacrylate (bis-gma) with unsaturated monomers were prepared. camphor quinone (cq) of 1 wt %, 2-dimethyl amino ethyl methacrylate (dmaema) of 1 wt % have been applied in photo-initiation system for the purpose of initiating matrix resins’ co-polymerization. wear resistance, flexural strength, hardness and compressive strength were measured. the results indicated an increase in the mechanical properties in the samples containing nano-size filler particles. it is interesting to note that, this improvement was observed at much lower nano-size filler content. physicochemical properties, such as solubility (sl), water sorption (ws) as well as the volumetric shrinkage (vs) have been examined. ft-ir as well as sem have been utilized for implementing the characterization. sem has been applied for showing particle size distribution as well as the particle agglomeration that is related to the treated nano-fillers in nano-composites. ft-it is initially applied for identifying qualitative compositions regarding the nano-composites’ compositions. the thermal stability of all dental nano-ocomposites was also studied using tga and dsc techniques. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction using dental composite for the purposes of filling material is becoming widespread because of the need for more esthetic filling materials, also due to the laws banning amalgam in certain nations. amalgam, considered as filling materials, was utilized for over one-hundred and fifty years; also, in many places of the world it is still applied. it can be defined as alloy of mercury as well as other metal including copper, tin, in addition to silver. over the years, there was a debate regarding if amalgam can be considered toxic or not toxic, yet, this debate is still not settled [1]. a major drawback of applying dental composite material is that they have micro-mechanically retentions to the surfaces of the tooth, and that makes under-cuts needless for the composite filling, yet not in the case of applying amalgam. on the basis of combinations of various particles as well as their filler size, the http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 23 dental composites could be categorized. also, their viscosity is used to classify them. there are 2 major phases related to composites: inorganic and organic. there are various types related to monomers included majorly in nonpolymerized organic matrix. the major monomers applied in composite include bis-gma, tegdma as well as udma. the composite has high viscosity due to the heaviness and stiffness of bis-gma. tegdma can be defined as molecule that is small and flexible, also its molecular weight is low, and that make its viscosity less in comparison to bis-gma, also it is more possible to be subjected to greater polymerization shrinkage. the viscosity of udma is low in comparison to bis-gma, also it could be utilized alone, however it is frequently combined with certain other monomers in the composites that are used currently, for the purpose of improving different performances [2]. to add inorganic glass filler particles is another approach for reducing shrinkage. maximal filler loadings could be reached via utilizing various sized shaped as well as sized filler particles. the composite’s consistency is impacted via the shape, size and amount of the fillers. the small particle as nano-fillers, provide high gloss in the case when polishing the composites which will lead to optimum esthetics [3,4]. recently, the size of the filler particles has been small and the majority of composites used today consist of small amount of nano-particles. the majority of dental composites are considered to be hybrids, and they can be categorized to nano-hybrid or micro-hybrid composites according to their filler load as well as their filler size. by definition, there are filler particles from at least 2 filler size range are included in each one of the composites. the size range of the particles is in (10nm 10μm). the range of the filler particles that are relate to micro filled composites is between 10nm and 50μm. nano-composites include cluster or particles of the size range (1nm 1.4nm) [2,4]. nano-materials could be defined according to european commission, no less than fifty percent of particles should be in size range (1nm 100nm) [5]. the process of curing is initiated via the curing light. in the case of applying light, monomer polymerize and create rigid structures referred to as polymer networks. throughout the polymerization process, double bonding will be converted to single bonding between carbon molecules. the distance between molecules will be shortened because of such conversion, which will lead to polymerization shrinkage. following polymerization process, the composites will be converted to solid structures. polymerization shrinkage might result in more sensitivity, secondary caries, stress, cracks, dis-coloring, and gaps in the restored tooth [4,6,7]. stress which is created via the vs at tooth-restoration interface will create marginal gaps, that unfavorably impact the resin composite restoration’s longevity. there are many aspects could impact the polymerization shrinkage such as the prepolymerized particles, filler particles type, filler load, monomer systems, and so on. [8]. the resin composite’s vs is detected via the resin matrix compositions as well as the filler content [9]. also, kleverlaan et al. showed that the resins in resin composites will be decreased with the increase in filler load which will result in reduction in shrinkage [10]. with regard to the presented study, the aim is to check the 5 monomers that can enhance the mechanical characteristics as well as the polymer network structures, in the case when co-polymerized. for the purpose of achieving such task, various compositions, majorly applied in dentistry field, that consist of tegdma as well as bis-gma in addition to unsaturated monomer (methyl methacrylate, (2-hydroxyethyl)_ methacrylar, triethylene glycol dimethacrylate, 2,2 propyl bisphenyl glycidyldimethacrylate), have been altered through the co-polymerizing process, bis-gma with the un-saturated monomers. furthermore, sl, flexural modulus, ws, hardness, vs, wear resistance, and sem morphology have been examined. ft-ir and sem have been applied for implementing the characterization. sem has been utilized for showing particle agglomerations as well as particle size distribution that are related to the treated nano-fillers in nano-composite. ft-ir has been initially applied for identifying qualitative compositions regarding the compositions of the nano-composites. thermal stability that is related to all the dental nanocomposites has been examined through the use of dsc and tga methods. 2. experimental work 2.1. materials and system methyl methacrylic (mma) (merck), (2-hydroxyethyl)_ methacrylar (2-hema)( merck), 2,2 propyl bisphenyl glycoldimethacrylate (bis-gma)(usa), triethylene glycol dimethacrylate (tegdma)( aldrich), zinc oxide (zno)( gcc), zirconium oxide nanoparticles (zro2)( skyspring nanomaterial), silicon oxid nanoparticles (sio2)( skyspring nanomaterial), nano hydroxy apatite (ha)( skyspring nanomaterial), 2-(diethyl amino)ethyl acrylate(aldrich), camphorquinone(aldrich). 2.2. apparatuses digital sensitive balance, sarorius, bl210s, germany, mixter, scanning electron microscopy (sem)(jeol ,japan), ftir tensor 27, fourier transform infrared spectroscope, bruker, germany., (thermogravimetry analysis (tga) were performed on a polymer laboratories co england, model pl-tg at iran polymer and petrochemical institute, using a heating rate of 10ºc/min in argon atmosphere within the temperature range of (25800ºc). differential thermal analysis is measured using apparatus (dsc) type (dsc 131 evo, setaram ,france) in the college of education for pure science ibn – al haitham central service laboratory/university of baghdad. properties are measured using a tensile testing machine from ( laryee co)/ china under a load cell of 20 kn and a cross-head speed of 200 mm/min at room temperature. the sample dimensions were accordance to astm d-412. 2.3. fabrication of experimental dental nano-composites (a1-a3) the experimental dental nano-composites have 2 series, which have been subjected to a process of fabrication through mixing fillers as well as the monomer matrix. monomer matrix (bis-gma, 2-hema, mma, and tegdma) has been subjected to mixing process in the mass ratio (40/20/20 and 20) for one hour. after that, a process of adding the zinc oxide (0.5gm) as antimicrobial agent has been implemented, also a process of adding a nano-filler (0.7gm) as a colorant has been also implemented for improving the mechanical characteristics. after that, a process of adding dmaema (0.5 wt%) as accelerator and camphor quinone (0.5 wt%) as initiator has implemented and continuous for twenty minutes. then, the paste has been inserted to the test moulds and the light cured with the use of a light curing unit (eliparfreelight2led, 3 m espe) at 1500 mw/cm² intensity. light has been illuminated on the two surfaces, bottom and top, via clear matrix strips for forty seconds. since it is majorly applied via clinicians, curing time of forty seconds has been applied for curing the experimental nano-composites. tip distance that is related to light curing unit has been kept at 1–2 mm from the surface of the surface. the concentration of materials is explained in table 1. 24 mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 table 1: monomers and photo initiators used in this study sample no. bisgma(%) 2-hema(%) mma(%) tegdma(%) nano fillers (0.7 gm) initiator camphorq-uinone dmaema a1 40 20 20 20 sio2 nano 0.5 wt% 0.5 wt% a2 40 20 20 20 zro2 nano 0.5 wt% 0.5 wt% a3 40 20 20 20 hydroxy aptiate nano 0.5 wt% 0.5 wt% 2.4. the process of curing the monomers have been mixed with: 0.4wt% camphor quinone (cq, sigma-aldrich) the photo-sensitizer and 1wt% n, n-dimethylaminoethylmethacrylate (dmaema, sigma-aldrich) the reducing factor and with vigorous stirring, poured to moulds petri dishes (with a diameter of 120mm and thickness of 4mm). those samples have been covered by pet film for the sake of reducing the impacts of the inhibition of oxygen and after that, irradiated, at a room temperature, for half an hour. photo-polymerization has been started by a mercury vapor lamp of high pressure (famed1, model l6/58, lodz, poland, power 375w [11, 12]), which emits ultra-violet/vis light, where camphorquinone is absorbed in a range between 420 nm and 500 nm [13]. 2.5. measurement of volumetric shrinkage (vs) the vs related to dental resins has been examined via the variations in density pre and post the process of photo polymerization, also, the archimedes principle is used to determine the density. measurement is carried out with the use of commercial density determination kits related to the analytical balance mettler toledox on basis of iso17304:2013 (e). 2.6. measurement of water sorption (ws) and solubility (sl) water sorption (ws) and solubility (sl) have been acquired on the basis of iso4049 [14]. 2.7. scanning electron microscopy (sem) researches on the morphology have been carried out on the cured materials’ fractured surfaces with hitachi tm3000 sem, tokyo, japan. sample surfaces, prior to observations, have been sputter coated in gold. 2.8. physico-mechanical properties of the test samples 2.8.1. flexural characteristics the flexural strength (σ) and the flexural modulus (e) are specified according to the iso178 . 2.8.2. compression set compression set was measured according to iso 1653 at ambient temperature. 3. results and discussions 3.1. prepared polymers synthesis and characterization 3.1.1. synthesis and ftir spectrum the preparation of dnc (a) has been done via co-polymerization process that is related to the 2-hema, mma, bis-gma, with cross-linker (tegdma), initiator (kps), the reaction was continued through a process of refluxing for two hours and at a temperature of 26 celsius under n2 gas for the purpose of removing dissolved oxygen, just as can be seen in reaction scheme (1): scheme 1: synthesis of polymer (a) figure 1. ftir spectra for (a) mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 25 ftir analysis there are many bands related to the infrared spectrum, majorly the wide range in range of (3300 3450) cm-1, that indicate overlaps the current absorption (oh). appearance of the beams in range of (2850cm1 2990cm1) to vibratory vibration that is related to aliphatic ch bonds in polymer’s structure. characteristic beams at 1725cm-1 indicate (c=o) of ester’s group, aromatic (с=c) are indicated at range of (1475 1600 cm 1). characteristic bands in range of (1390cm-1 – 1400cm-1) are the result of ( c – h ) bonds for the (ch3) group of polymers. the absorption bands in range of (1000 1100cm1 ), ( c–o ) as can be seen in fig. 1: 3.1.2. water sorption and solubility (ws) water sorption (ws) and solubility (sl) have been acquired on the basis of iso4049 [14]. steel split mold has been utilized for making the specimens with diameter of (15 millimeter) and (1 millimeter) thick (n=5). ws has been decreased reduced through using extra hydrophobic monomer, preventing the hygroscopic expansion. water sorption might be accounted for the adverse effects such as discoloration and subsequent swelling of restorative materials. with regard to the present study, there has been an increase in the water sorption with the reduction in conversions of the tested formulation, because of their molecule’s hydrophobic character, as well as the elevated conversion, bis-gma presented with the lowest water sorption [15]. with regard to the n,n mbaa , elevated conversions do not translate to elevated cross-linking density, as mentioned earlier, thus second to last lowest water sorption has been fairly unpredicted [16], also it should be associated with its low hydrophilicity in comparison to bis-gma. very comparable water sorption values have been shown by hydrophobic monomers and bisgma, despite differences in the conversion, possibly due to the fact that these are considered to be the major hydrophilic molecules assessed in the present study. in addition to being dependent on hydrophilic character and amount of leachable in products, the results of solubility are on the basis of amount of water absorbed in network. furthermore, the pendant double bonds which are contributing to greater free volume to network [17] and favor ws, could not be contributing to the leachable species (oligomers and monomers), due to the fact that they’re tied to network. this might explain the reason behind solubility values being related to bis-gma have not been greatest among homopolymers, regardless of its considerably more elevated ws. n,n mbaa , at the same time, because of tendency to cyclization, indicated the highest results of sl, despite low water sorption and high conversion, probably due to the fact that the oligomers of lowmolecular-weight have been existent and ready for leaching. the low sl results from the bis-gma have been clarified through the hydrophobic character as well as the high conversion (with regard to this condition, possibly also with greater cross-linking) of molecule. also, it must be indicated that the results of sl could be undervalued for more hydrophilic monomer, due to the fact that the water yield stronger hydrogen bond interaction with the hydroxyl and (in bis-gma), as well as weak bond with the ethylene glycol unit (which are presented in great concentrations in n, n mbaa ), the could be hindering the water elimination throughout the 2nd period of storage in desiccators [16]. it appears that the distinct characteristics which are related to tested dimethacrylate homopolymers are the cause of their unique behavior with regard to the flexural properties, polymerization kinetics, ws and sl. these properties explain using the copolymers for the purpose of obtaining high dc and mechanical characteristics, in addition to optimum resistance to water degradation. it can be indicated that, before water immersion of bis-gma-based resin would be similar after water immersion, which can be an indication of its more effective water resistance. wsl reveal the amount of the unreacted monomers which are leached out of the polymeric networks. the major cause of tissue inflammation as well as cytotoxicity is the monomers’ release [18]. it has been indicated that degree of conversion (dc) and wsl are related, and low wsl could be the result of high dc [19]. this must be based on un-reacted monomers’ leachability in polymeric networks. intermolecular hydrogen bond that is created via -nh is weaker than the hydrogen bond created via -oh, due to the -oh group’s high cohesive energy density [19]. thus, unreacted monomers can undergo a process of absorption to surrounding networks more firmly in bis-gma based polymers in addition to being to leach out of polymers, which might lead to low wsl regarding the bis-gma based polymers. bis-gma monomers result in more hydrophobic molecule; thus, the materials will have less susceptibility to liquid’s sorption as can be seen in fig. 2. since the polydimethacrylates can be considered as cross-linked dental polymers, and because of the polymer chains have cross-links between them, this will typically lead to considerable reduction in polymer’s solvent permeability since the reduce the capability related to polymer chain for swelling as well as reducing hole free volume [20]. nevertheless, ws could be defined as needed impact as the composites’ hygroscopic expansion was indicated to the close marginal leakage gap because of the shrinkage [21]. at the same time, a significant standard for the dental composites is the sufficient resistance to degradation via water and other solvents. it has been indicated that the dental composites are leaching only (0.02-0.05 percent) of their total mass to the aqueous solution through the first thirty days, this is the result of inorganic nano-fillers. 3.1.3. volumetric shrinkage the volumetric shrinkage (vs) values which are related to the specimens of the composites have been assessed on the basis of archimedes principle. uncured sample has been left to rest for one minute for the purpose of eliminating the impact of the slumping on measurements, then it has been exposed to 40s light curing, and the curing unit tip was placed at a distance of (1-2 millimeter) from specimen. the assessment is implemented through the use of commercial density determination kit of analytical balance mettler toledo x on the basis of iso17304:2013 (e). one of the main disadvantages, particularly in the dental composites is that their polymerization shrinkage could result in secondary caries and marginal gaps in restored teeth. shrinkage is caused by the composites’ matrix-phase polymerization, also it is a main disadvantage in the dental resin-monomer. the polymerization of resin is accompanied by the volumetric shrinkage. as the polymerization proceeds, van deer waals distances have been modified to covalent bond distance which results in volumetric shrinkage. the shrinkage degree is represented through the number of the created covalent bonds that is defined as the polymerization reaction’s extent. another reason for the volumetric shrinkage is that the molecular distances between polymer chains become smaller than the molecular distance between monomers [22]. since the stresses generated from polymerization shrinkage cause defects of deboning at the tooth-restorative interface [23,24], one of the main issues in the dental composites is to eliminate or decrease the polymerization shrinkage. in the case when the monomer in the proximity react to create covalent bonds, there will be a reduction in the distance between atoms groups, also the free volume will be decreased, that will lead to vs magnitude experienced through composites has been decided through its filler volume fraction as well as the conversion’s degree and composition 26 mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 of resin matrix. as shown in fig. 3, the composite with the bis-gma presents much smaller volumetric shrinkage. the shrinkage values which were indicated for bis-gma (forty percent) and n,n mbaa (twenty percent) have been considerably more elevated than the shrinkage values related to the standard composites, that are in the range of 2 – 3 percent [25,26]. such difference is the result of the fact that in the hybrid composite, about sixty percent of volume has been occupied through filler particle. even though that the inorganic content related to micro filled composites is approximately forty percent, their shrinkage values are considered to be comparable to hybrids, because of the existence of pre-polymerized composite particle, occasionally indicated as “organic fillers”, that will be rendering them in a way comparable to the hybrid composite with regard to actual volume fraction regarding the polymerizing resin. the shrinkage will also be affected via the diluents’ concentrations in resin matrix. a new study indicated that high ratios of n,n mbaa /bis-gma in the experimental composite will lead to high contraction stress value because of the elevated vs, due to the improved conversions [27]. due to the fact that they usually have low molecular weights in comparison to host monomers, the density of the polymerizable carbon double bonds will be increased via the “diluents” monomers that will result in more shrinkage. also, the reaction environment’s mobility will increase because of the tg as well as low viscosity of diluent, which will allow more effective conversions [28] previous studies showed that increasing light intensity resulted in more polymerization shrinkage for some composites, but not all materials [29,30]. in our study, the effects of each curing mode on two composite resins were compared where no significant difference was observed. each composite showed similar behavior in the face of modulation of the light intensity during photoactivation. therefore, it must be put into perspective that this result is valid only for two resin composites in this study. consequently, with regard to this study limitations, it might be indicated that the increase in the shrinkage of composites is related to the total energy of curing lights. further research in this area is necessary in order to reveal the polymerization shrinkage of other composite resins. 3.1.4. scanning electron microscopy monodispersed and spherical nano-particles were successfully synthesized. sem is used to evaluate both the morphology of nanoparticles and fillers composite surface following the fracture toughness test (sem, leo (zeiss) 1540xb). samples were prepared for sem by placing a small amount of the sample powder on sem tubes followed by coating with osmium in order to prevent charging of the samples and to reduce the nano-tube damage from the electron beam during imaging. surface treatment has been of high importance to develop and efficient dental composites. in the case when the filler’s size is not more than thirty nm, agglomerations as well as aggregation of the nano-particles will occur. thus, interfacial adhesions between the filler and the polymer matrix will be improved via the agglomeration filler dispersion. the improvements in the mechanical and surface characteristics might be the result of these enhancements. with regard to the presented study, zirconium oxide as well as nano-silica have been applied as filler, that has been mixed with various concentrations chosen of the monomer resin in addition to the additives for the dental restorative applications. using zirconium oxide fillers and nanosilica have been anticipated to have benefits and enhance the characteristics related to composite fabricated. klapdhor and moszner 14 have indicated that the mono-dispersed nano-filler in polymer matrix result in nanocomposite material of optimum mechanical characteristics, excellent process ability as well as high transparency. dnc a1. in this dnc (bis-gma, 2hema, mma) monomers at different concentration were used and crosslink (tegdaa) at 20% was used after that 0.7 gm sio2 and 0.5 gm zno2 were added. fig. 4(a) shows that spherical shapes with different size range of 29.4 -90.6 nm of nano silica composite with monomer were obtained. sem micrograph of each material is shown in fig. 4 (a and b) at two different magnifications. figure 2. water sorption (ws) and water solubility (sl) figure 3. volumetric shrinkage mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 27 figure 4 (a and b): sem image of nanosilica composite in dnc a2, the same monomers are used as in dnc a1 but it differs only in nano-filler that was used of 0.7 gm zro2 is added. fig. 5 (a) shows that spherical shapes with different size range of 75.7 -106.9 nm of zirconium oxide nanoparticles composite with monomer were obtained. sem micrograph of each material is shown in fig. 5 (a and b) at two different magnifications. figure 5 (a and b): sem image of zirconium oxide nano-particles composite 3.1.5. thermal gravimetric analysis (tga) study thermogravimetric analysis determines the change in mass as temperature’s functions. it can be mainly applied to specify degradation temperature, material’s absorbed content, the level of inorganic as well as the organic parts in the materials as well as residues of analysis solvent. it does use sensitive electronic balance through which a sample will be suspended in furnace, which is controlled through temperature programmer. thermal characteristics of 4 samples of such polymers have been examined by tga in argon atmosphere at heating rate (10ºc per minute) [31-33]. with regard to this test, many values have been recognized including ti, top, tf, t50%, residue at 600 celsius, and char yields at 400 celsius as can be seen in table 2. temperatures of fifty percent weight loss of (dnc a1dnc a3) of polymers have been between (384-409) ºc, the char results of (dnc a1) are 79%,(dnc a2) are 78% , (dnc a3) are 77% at 500 ºc in argon atmosphere, indicating that they could satisfy the requirements of temperature resistance that may be utilized in a variety of applications. weight residue of (dnc a1) are 81.5%, (dnc a2) are 80% , (dnc a3) are 79% , at 600 ºc. table 2: thermal stability characteristics curves, thermal gravimetric analysis (tga) of polymers represents the temperature of decomposition. dnc dental nano composite top1 represents optimal temperature of decomposition. ti represents the temperature of the initial decomposition. t50% represents the temperature of 50% weight loss, which has been obtained from the tga. tf represents the final temperature of decomposition. the final degree of dissociation temperature char% at 400 ° c represents the residual weight percentage at 500°c in argon by tga. 3.1.6. differential scanning calorimeter analysis (dsc) study differential scanning calorimetry (dsc), is a technique of thermal analysis that investigates how material’s heat capacity (cp) is transformed by temperature. a known mass sample is heated or cooled and the variations in its heat capacity are observed as alterations in the heat flow. this allows to reveal transitions such as melts glass transitions (tg), and the melting point (tm) the crystallization degree (tc) (20). the results of (dnc a1) polymer showed in fig.6. the value of the glass transition (tg) of the mixture was 110° an increase in the flow of temperature and then increase the rate of absorption of the sample to the temperature until the melting point (tm) at (584° c) if completely melted and then the rate of absorption of the sample to heat and by the crystallization rate (tc) of the mixture was set at (150.3° c) .the results of (dnc a2) showed in fig.6. the value of the glass transition (tg) of the mixture was 111° c indicating an increase in the flow of temperature and then increase the rate of absorption of the sample to the temperature until the melting point (tm) at (580° c) if completely melted and then the rate of absorption of the sample to heat and the crystallization rate (tc) of the mixture was set at (145.4 ° c). the results of (dnc a3) polymer showed in fig. 6. the value of the glass transition (tg) of the mixture was 106 ° c indicating an increase in the flow of temperature and then increase the rate of absorption of the sample to the temperature until the melting point ( tm) at (584 ° c) if completely melted and then the rate of absorption of the sample to heat and the crystallization rate (tc) of the mixture was set at (11138° c) [34]. table 3: degree of glass transition, melting point and the degree of crystallization in the differential thermal analysis tc (cº) tm (cº) tg (cº) dnc 150.3 584 110 a1 145.4 580 111 a2 138 584 106 a3 dnc dental nano composite tg: degree glass transition tm: melting point tc: degree of crystallization dnc ti top1 tf t50% residue at oc600 char % at 500°c a1 318 351 456 384 81.5 79 a2 278 330 440 385 80 78 a3 280 350 455 409 79 77 28 mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 fig 6: tga and dsc fora1) composite dental with zro2, a2) composite dental with sio2 and a3) composite dental with ha. 3.1.7. flexural strength and elastic modulus the main objective in this study is to study the flexural strength of the composite samples containing various mass fractions of nano-fillers (sio2, zro2 and hydroxyapatite) as shown in fig.7. there is an initial increase in the flexural strength of the nano-particles filled composites as the filler content is increased from (0.66 to 8) wt.%. however, a decrease in strength values is observed at higher values of filler addition. going back to the results obtained for the flexural strength, it should be reminded that, one of the major factors affecting the mechanical characteristics of composite samples is extent of interfacial interaction. in other words, poor interfacial interactions prevent a sufficient transfer of stress between components. in such cases, the addition of filler particles is expected to increase the number of weak links and therefore have a negative impact on strength. therefore, we believe that the increase in the strength shown in fig. 7 is due to the reduced macromolecular mobility in the matrix and the drop in the strength. values are most likely attributable to the overcoming effect of poor filler/matrix coherence at higher values of the filler content. spherical and evenly distributed micrometer size filler particles can be observed and a closer examination of this micrograph indicates that, as a result of a strong interfacial bond between the filler and resin, some filler particles have been effectively forced out of the matrix during the mechanical testing. the modulus of elasticity values were calculated from these data and are presented in fig. 7. as indicated in this table, except for the case of the sample containing 4.6 wt.% nano fillers the increase in the content of the filler is accompanied with increased value of the elastic modulus. a possible explanation for the increased value of elasticity modulus is the more restricted motion of bis-gma matrix with an increase in the filler content [35]. once again, at some critical value of the filler content the sample behavior is dominated by the poor bonding at the interface causing a decrease in modulus value. an exponential dependence of modulus of elasticity on filler content has already been reported in the literature [36]. another point which can be concluded from the data is that there is no sign of plastic deformation prior to fracture in these samples. these results show that all nano-particulate containing samples have significantly higher mean strength than those of the nano-filled composite samples 1. this implies an effective stress transfer as a result of good bonding between the nano-sized particles and the matrix. it is also important to take into account that the filler fraction values were lower in the nano-size filler containing composites compared to the nano-filled composite samples prepared in this study. in summary, the data presented in this study on the mechanical properties of the nano-sized filler containing samples, indicates that in spite of the lower weight fraction, the use of nanosize nano-fillers particles resulted in a considerable enhancement in the mechanical properties of the dental restorative composite samples. obviously, several factors are at play, but we believe that maybe the most important is the favorable adhesion between the nano-sized filler and the polymeric matrix. incorporating of nano-fillers in dental composites enhanced the flexural strength by over 100%. the flexural strength enhancement may be a result of increased area of the surface of the particles of the filler due to the reduced size of the particle that produces high energy of the surface at interface of the filler-matrix. this results from the capability of those nano-particles in hindering the propagation of cracks within the matrix of the dental composite based on the mechanism of the strengthening, in addition to strong bonding between those particles and the resin matrix. adding ha, sio2, and zirconium oxide as nano-particles leads in increasing both dental nano-composites’ flexural modulus and strength. the cause of this kind of behavior is that high shear strength of the interface, between matrix of the resin and the nano-particles of each of ha, sio2, and zirconium oxide associated with the creation of physical cross-link bonding shielding or covering nano-particles, which successively prevent cracks from propagating inside the material, according to foregoing. in addition to that, incorporating brittle nano-particles in the matrix of the polymer enhances composite stiffness with the restriction of polymer chain mobility in nano-composite. and sufficient nano-particle distribution, particularly at low nano-particle additive percentages to composite materials, as it has been performed in the present study nano-particle content’s volumetric fraction in composites not higher than18% ratio) which decreases nano-particle agglomeration in the composite, which could result in the reduction from location and the density of stresses are insufficient for breaking weak interface interactions. which is why, those small concentrations of the stress may be transferred easily from the matrix to brittle nano-particles, thereby permitting particles in contributing their property of the high brittleness to composites therefore, it result in increasing both flexural modulus and strength. 3.1.8. compressive strength the strength of nano-fillers reinforcement resin which is under compressive loading has been evaluated with the approach which is used to test nano-fillers. the values were stated in fig. 8 for compressive strength values of synthetic polymer which is reinforced by nano-fillers of a variety of average size of particles. some other materials, which are presently in general utilization, have been illustrated for comparisons. specimens made by nano-fillers had high compressive strengths which gives the confirmation of the existence of differences that are statistically significant between all groups of samples. moreover, the results of the compressive test have shown the differences amongst samples sio2 (10-30nm) < zro2(20-30) nm < ha (60) nm. the testing of compressive strength is utilized to assess mechanical characteristics of this type of material. due to the fact that the majority of the masticator loads belong to compressive forces class. there is a considerable importance in evaluating the resin material durability in that conditions [37]. advancements that have been accomplished in the area of nano-technology had a great influence on resins composition [38]. many different types of composite were produced and presented according to the nano-technology. there is an importance of compressive strength measuring in vitro research which were characterized as sufficient indicators for the simulation of functional forces which have loaded upon the restorative materials that are under mastication [39,40]. consequently, in the present work, nano-composite resin’s compressive strength has been projected. composite resins that are nano-filled combined with nano-cluster formulations that reduce filler particles’ interstitial spacing to nano-sized particles presents higher loading of the filler, advanced physical characteristics, in comparison to these complexes. the mahdi saleh mahdi and mohammed ali mutar /al-qadisiyah journal for engineering sciences 13 (2020) 022–030 29 average sizes of filler particles range between 10 nm and 30nm. spherical shapes include numerous benefits such as improvements in the filler load of the composites as well as increasing fracture strengths due to the fact that mechanical stresses tend to be concentrated on filler particles angles and protrusions. the majority of the nano-composites have filler particles that are spherically-shaped with improved filler load. in the present research, nano-composites have higher compressive strengths compared to compressive strengths of the other dental-composite. the present research agrees in increased strength value of the nano-composite resin. it has appeared that besides greater sizes of filler particles in dental composite resins, the existence of sio2, hydro-apatite, and zirconium fillers have a significant role in its enhanced strength. the existence of aromatic cycles in the monomers such as bisphenol di-methacrylate and bis-gma has been detected in dental composites results in reducing cyclizing and increasing cross linking in the polymer and provides consecutive enhancement in strength/durability and mechanical characteristics. none-the-less, in acrylate and tegdma monomers particularly as a result of its high flexibility, there’s more chance of intermolecular cyclizing. in a way that bis-gma stiffness is a factor in improving compressive strength as well [41]. esthetic properties of the nano-composites are analogous to the esthetic characteristics of the natural teeth. due to the fact that they are of a sufficient wear resistance they result in no enamel wear of analogous teeth. their polymerization shrinkage is quite minor, which is why, they have less tension which results in decreasing of the over-sensitivity of postop. there are filler particles in the nano-composites, and they enhance the strength of the matrix and produce higher toughness to fractures [42, 43]. therefore, nano-composites of high compressive strength that utilized in the present research may be clarified with their higher loadings of the filler. numerous researches reported the correlation between the volume fraction and the mechanical characteristics of the fillers [44-46]. figure 7: show the flexural strength of nanofiller-reinforced composite dental figure 8: compressive strength of nano-fillerreinforced composite dental 4. conclusions this work has been focused on synthesizing a new bis-gma-based composite resin with nano-fillers (ha, sio2, and zro2) for the use in the field of dentistry as restorative material. the filler that has been newly synthesized was a powder of white color, with carefully chosen particle sizes. the use of nano-sized fillers particles has proven highly effective in the improvement of mechanical characteristics. another benefit of the nano-size reinforcement agents in comparison with the micro-sized particles has been the lower loading requirement. the enhanced mechanical characteristics which are shown by the complexes that include nanoparticles is mostly a result of more efficient interaction of filler/polymer. a nano-particle dispersion of higher efficiency, in combination with higher loadings could result in a more enhanced complex dental restorative material. additional researches are required for improving interactions between nano-sized fillers and matrix phase and in addition to that, increasing nano-filler particles’ loading capacity to the matrix of the polymer. in spite of the limitations of the present study, it might be concluded that dental nano-composites that are synthesized have several advantages, such as better water resistance and lower volumetric shrinkage even the dental composite water solubility was small. references [1] j. mutter, “is dental amalgam safe for humans? the opinion of the scientific committee of the european commission,” journal of occupational medicine and toxicology, 6(1), 2, 2011 . 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[47] a n. khaled, “physical properties of dental resin nanocomposites,” master thesis, university of manchester school of dentistry, 2012. article al-qadisiyah journal for engineering sciences 13 (2020) 068–073 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: salih.rushdi@qu.edu.iq (salih a. rushdi) https://doi.org/10.30772/qjes.v13i1.650 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. an experimental investigation of overall mass transfer coefficient (kga) of co2 absorption using monoethanolamine (mea) and diethanolamine (dea) in a bubble column reactor (bcr) elaf thamera, salih rushdi a* a chemical engineering department -college of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 19 january 2020 received in revised form 26 march 2020 accepted 30 march 2020 keywords: co2 absorption monoethanolamine (mea) diethanolamine (dea) overall mass transfer coefficient (kga) bubble column reactor (bcr) gas chromatography(gc) a b s t r a c t in this work, an absorption technology was used actually to investigate the mass transfer coefficient of carbon dioxide from a gaseous mixture (air, carbon dioxide) in blended solution monoethanolamine (mea) and diethanolamine (dea) in a bubble column reactor (bcr). the bubble column reactor(bcr) was made of plexiglas with 1.5 m high and 0.1 m inside diameter. the overall mass transfer coefficient (kga) was evaluated at different operating conditions, gas flow rate, air flow rate, liquid flow rate. where the gas flow rates were 10, 15, and 20 l /min, air flow rate 100,150 and 200 l/h, and liquid flow rate 5,10,15 l /min. this experiment by using a continuous process with helping the centrifugal pump. high-performance gas chromatographic (gc) was performed to evaluate co2 loading during absorption experiment . the experimental results have shown that the co2 loading in range of 0.581-1.367 (mol co2 /mole amine), and the maximum value of overall mass transfer coefficient (kga was 0.04 s -1). © 2020 university of al-qadisiyah. all rights reserved. 1. introduction with regard to this century, elevation in the emissions regarding atmosphere’s anthropogenic(co2) is considered to be challenging due to the fact that it is mainly contributing to the global warming. fossil fueled plants are main emission’s source, particularly plants using coal as main fuel. co2 is one of the gasses that are naturally-occurring, also it has main impact in reflection related to the solar radiation back to earth, and that will keep the surface temperature of planet in suitable levels for the life. furthermore, throughout the past tens of years, there has been an increase in the emissions related to other greenhouse gases (ghgs), in addition to co2 , such as ch4, n2o, hfc, per fluorocarbons as well assf6 [1], [2].worldwide, co2 which is emitted from the power plants is considered to be about 40% of the overall emissions of co2 and within the ongoing businesses and industries, it is anticipated to be elevating to about 60% prior to the end of this century [3]. as co2 is released excessively via power plants, industries, in addition to other sources is of high importance in life cycle of earth and also to the global climate [1]. for the purpose of preventing excessive co2 release in atmosphere, carbon capture and storage (css) is of high importance in the industry of fossil fuel. such approach includes co2 capturing, compress it to transport and after that store it permanently (in gas fields and depleted oil). the major application regarding css is in the industrial point sources as fossil-fuel power plants, production of fossil fuel, facilities for hydrogen production, industrial http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i elaf thamer, salih rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 068–073 69 plants (steel and iron blast furnaces, chemical processes, and cement kilns) [4]. today, the absorption is the most important approach to remove co2 from the industrial waste gases as well as for synthesizing and for purification of natural gas. such process pass flue gas via liquid which have the ability of absorbing co2 (in absorber vessel) and after that releasing co2 at increased temperatures in regenerator vessel (stripper) [5]–[7]. aqueous alkanolamines are the major chemical solvent for capturing acid gaseous. alkanolamines have been generally applied as absorbents for the capturing of co2, alkanolamine’s structures involve primary, secondary, ternary amines including no less than single (oh) as well as amine group. with regard to the chemical solvents, primary amines like mea, secondary amines dea, aminoethoxyethanol (dga) as well as diisopropanolamine (dpa), also tertiary amines like tea and mdea, as well as alternatives to amines like the hot potassium carbonate are utilized. such alkanolamines were applied as chemical absorbents for removing acidic gases like (h2s ,co2 ). a lot of the works on the chemical absorption with the tertiary alkanolamines like dea, tea, in addition to their associated apply of mixed amine absorbents, particularly blends the primary and tertiary amines (like tea and mea) or the secondary as well as tertiary amines (like tea and dea) has increased or them together [8]. the main benefits related to the technology of chemical absorption are as follows [9]: 1. chemical absorption can be considered as major developed approach to capture co2 , operating at normal pressure and temperature. 2. for tens of years it was commercialized, though not for the capture of co2 from power plants. 3. it can be used efficiently to dilute co2 system (general flue gas from power plants) . also, there are certain disadvantages related to this approach, as follows: 1. amine oxidative degradation through so2, no2, and o2 in flue gases that induce high absorbent makeup rate. 2. the energy consumption is high throughout high temperature absorbent regeneration. 3. the equipment corrosion rate is high. 4. the equipment size is large. 2. theoretical background as a result of the benefits and drawbacks of single amine solvents, blended amines became one of the attractive directions in the existing research area. blended amines combine the benefits of the primary and the secondary amines, reacting fast with the co2.through the combination of those advantages, and as a result, tailoring the solvent, it is possible achieving more sufficient absorption efficiency at low partial pressure, in addition to high kinetics of absorption for the reactions with the co2 [10]. the several reaction steps can be occurred through absorption process using aqueous blend of (mea+dea).the mechanism of the “zwitterions” which has been first presented in 1958 by caplow and re-introduced in 1979 by danckwerts, is, in general acknowledged as the mechanism of the reaction for the formation of the carbamate between co2 with primary amines and secondary amines. based on caplow, the bond of hydrogen is created between amine and molecules of water prior to any reactions with co2. at first, an unstable intermediate has been created as a result of bonding between the molecules of the carbon dioxide and the amine. then, carbamate is created through the transfer of an amine proton. the base which is typically utilized is either an amine or a water molecule .generally, the industrial amine sorbents’ utilization was centered on the aqueous solutions of the primary amines as well as the secondary amines, reacting with co2 directly for forming ions of the carbamate rnhcoo − . the chemical equations may be reduced to 2 significant steps, i.e., carbamate formation, bi-carbonate formation, and carbamate reversion. eqution (2) illustrates the carbamate ion formation for the primary amine. a comparable reaction takes place for the secondary amines. 𝐑𝐍𝐇𝟐 + 𝐂𝐎𝟐 → 𝐑𝐍𝐇𝐂𝐎𝐎 − + 𝐑𝐍𝐇𝟑 + (1) 𝐑𝐍𝐇𝐂𝐎𝐎− + 𝐂𝐎𝟐 → 𝐑𝐍𝐇𝟐 + 𝐇𝐂𝐎𝟑 − (2) according to blended amines, in the combination of (primary and secondary amines) , the over-all reaction rate for the capture of 𝐂𝐎𝟐 can be reduced to [11]: 𝒓𝒐𝒗𝒆𝒓𝒂𝒍𝒍 = 𝒌𝒐𝒃𝒔(𝐂𝐎𝟐) (3) 2.1. mass transfer for gas absorption mass transfer can be considered as one of the common phenomena which happen in simple, daily life in addition to the engineering process . in the case of absorption, the absorption of the gas in the liquid happens in the case of the transfer of the gaseous components from gasto liquidphase. in the process of the chemical absorption, the gaseous component is undergoes the absorption by liquid phase through combining the reaction and the diffusion mechanism. the processes of the chemical absorption are like systems that are aqueous amine-based, systems that are based on the ionic liquids, and ammonia manufacturing systems. as an explanation, the entire process rate can be viewed a layer of gas–liquid contact. the mass transfer must be enhanced with the increase of the turbulence in each of the liquid as well as the gas phases. the mass transfer happens through combining the diffusional and the mechanism of the chemical reaction in the boundary layer so the entire rate may be represented with each of the mass transfer and the chemical reaction. numerous hypotheses may define the process of the gas absorption, like the penetration theory, film theory, boundary layer theory, and the surface renewal theory. nomenclature kga overall mass transfer coefficient (𝑆−1) greek symbols kl liquid side mass transfer coefficient ( m/s ) δ film thickness (m) kg gas film physical mass transfer coefficient ( m/s ) ρamine density of amine [kg m3⁄ ] qg gas flow rate, ( 𝐋 𝐒 ) α co2 loading [mol co2/mol amine] f1 molar flow rate of co2 at inlet, [ 𝐦𝐨𝐥 𝐒 ] ρ co2 density of co2 [kg m 3⁄ ] 𝐧𝐜𝐨𝟐,𝐚𝐛𝐬 number of moles of 𝐶𝑂2 absorption [mol] subscripts bcr bubble column reactor 70 elaf thamer, salih rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 068–073 the film model which is simpler mathematically, compared to the models of penetration is usually utilized, based on the film theory, a stagnant film of thickness δl is supposed to be existing at gas and liquid interface as has been illustrated in fig. 1. the mass transfer through the molecular penetration takes place via a thin liquid gas layer which is δ thick, and there isn’t any concentration gradient in liquid bulk. in the theory of the film, the coefficient of the mass transfer k l and kg are proportionate to the coefficient of the diffusion dco2-amine and inversely proportionate to the thickness of the film. k l stands for the mass transfer coefficient for the liquid side and is equal to: 𝛅𝐋 = 𝐃𝐂𝐎𝟐−𝐚𝐦𝐢𝐧𝐞 𝐤 𝐋 (4) in a similar way, the equation below may be resulted for the coefficient of the mass transfer in gas phase: 𝛅𝐆 = 𝐃𝐂𝐎𝟐−𝐚𝐦𝐢𝐧𝐞 𝐤𝐠 (5) figure 1. carbon dioxide mass transfer into the liquid phase with chemical reaction based on the film theory 2.2. determining the overall mass transfer coefficient (kga) mass transfer coefficient is an important part of this research. mass transfer occurs when a component. in the scrubber, a simulated mix of gas which contains a (co2) and b (air ) which flow to a bubble column from bottom continuously contacts with the solution of the amine which flows from the top in the column. the two streams contact with the column countercurrent in a simultaneous manner. in the present study, has been a reasonable theory. taking under consideration the ideal gas law for inlet and outlet gases at a variety of temperature values, f1/f2 may be substituted by (p1 /p2 )(t2 /t1 )(y1 /y2 ). which is why, the coefficients of the general volumetric mass transfer becomes [12]: 𝐊𝐆𝐚 (𝐬 −𝟏) = 𝐐𝐠 ( 𝐋 𝐬 ) 𝐕𝐋 (𝐋) 𝐥𝐧 𝐅𝟏( 𝐦𝐨𝐥 𝐬 ) 𝐅𝟐( 𝐦𝐨𝐥 𝐬 ) (6) where : qg=gas flow rate, ( 𝐋 𝐒 ) f1=molar flow rate of co2 at inlet, [ 𝐦𝐨𝐥 𝐒 ] f2=molar flow rate of co2 at outlet, [ 𝐦𝐨𝐥 𝐒 ] vl=is the volume of liquid in the absorber. 3. experimental design a continuous bubble column was used to study the capture. the concentration of blended amine was 10v/v% mea+5 v/v% dea. in order to reduce the large amount of experiments, the taguchi method was used as the experimental design [13]. this study utilized three levels for the variables. when using the taguchi method, a minimum number of experiments are required to be calculated, as based on the following equation: n = 1 + ∑ (𝑳𝒊 − 𝟏)𝐍𝐕𝐢=𝟏 (7) table 1 presents the combination of experiments in the orthogonal array for continuous process. table 1. orthogonal arrays for experimental design for continuous process experiment no. (gas flow) l/min (air flow) l/h (liquid flow) l/min 1 10 100 5 2 10 150 5 3 10 200 5 4 15 100 10 5 15 150 10 6 15 200 10 7 20 100 15 8 20 150 15 9 20 200 15 4. experimental procedure a continuous bubble-column scrubber is a powerful process in the removal of co2 as compared with other scrubbers since it has a simple construction, higher heat and mass transfer coefficients, higher removal efficiency, and effective control of the liquid residence time. so, a continuous bubble column reactor has become the absorber adopted by some researchers. the chemical solvent employed that used are shown in table 2. table 2. chemical materials(amines) used in this work density g/cm3 molecular weight [g/mol] chemical formula abbrev chemical name 1.0117 61.084 c2h7no mea monoethanolamine 1.097 105.137 c4h11no2 dea diethanolamine initially , flue gas was simulated by combining individual streams of 𝐶𝑂2 from gas cylinder and air from air compressor. rotameters of the unit liter per minute (lmin−1) and (lh-1) were installed for controlling the gas flow rates and air flow rate respectively . for 𝐶𝑂2 gas the range of (𝐶𝑂2 flow rate) was 10-20 l min−1 and for air it was 100-200 l h-1. the experiment set up were carried out in a bubble column shown in fig. 2. aqueous solution of amines prepared (solvent) was pumped from the solution tank at a given flow rate range between (5-15)l/min to the top of the column , and a needle valve was installed on the top of the column to control the liquid flow rate so as to create counter current contact between gas and liquid. elaf thamer, salih rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 068–073 71 after absorbing co2 and traveling through the column ,this operation was continued for at least 10 minutes to allow the system to reach steady state conditions , the co2-rich solution was then collected continuously in the liquid receiving tank. a drain valve was introduced at the bottom of the column for emptying the column after the process and collecting the sample liquid. at the same time, liquid samples were taken from the bottom of the column and analyzed for their concentrations and co2 loading. figure 2. schematic diagram of bubble column reactor for absorp tion process 5. results and discussion the experiments for mass transfer in a bubble column were studied based on co2 absorption into blended solution from mea-dea. sample taken after absorption experiments were analyzed for co2 and amine content .in order to determine the co2 loading capacity in term of (moles of co2 per moles of amine).gas chromatography (gc) was used to analyze the concentration of co2. in this work high performance a shimadzu gc8a gas chromatograph was used for analysis the samples that were obtained in experimental work in the laboratory of scientific studies and research in the region of algiers al-diwaniya (iraq) .block diagram of a typical gas chromatograph is shown in fig. 3. figure 3. block diagram of a typical gas chromatograph the instrument is a gas chromatograph-mass spectrometer or gc-ms ,where a thermal conductivity detector tcd was used with 60 m /amp detector current and temp.270℃ ,it is measures changes in the exiting gas stream. a porapak-q column (2 x 2.5 m, the initial and final temp. of column was 120℃-240℃) . one of the gases called the carrier gas (here used helium gas, helium (ig) with flow rate 20 milliliters/minute )flows into the injector, through the column and then into the detector. a sample is introduced into the injector usually with a syringe or an exterior sampling device. co2 loading was calculated by integrating differences between the concentrations of injected co2 and the concentrations of emitted co2.all the absorbents used in the experiments reached equilibrium at an appropriate time ,when completion of the reactions between co2 and the absorbents. the amount of the co2 before being injected into the reactor and the amount of the co2 emitted after reactions were calculated by applying the ideal gas equation. the absorption loading of co2 of (mea +dea) as shown in table 3. which is in the range of(0.581–1.367) moles of co2 absorbed per mole of amine.the overall mole of co2 absorbed in the absorbent can be calculated by subtract mol of co2 inlet from out let and the co2 loading can be calculated through. co2 loading is defined as mole of co2 absorbed per mole of amine. nco2,abs = nco2,in − nco2,out (8) 𝛂 = 𝐦𝐨𝐥 𝐨𝐟 𝐂𝐎𝟐 𝐦𝐨𝐥 𝐨𝐟 𝐚𝐦𝐢𝐧𝐞 (9) in fig. 4 we found that an increase in the 𝐶𝑂2 loading of an absorbent with increasing time and mean that the solubility of carbon dioxide is increased under various parameters condition. it can be prediction that the co2loading capacity for aqueous blended amine solution increases, as the contact time (in the pilot unit) between the solutions and the co2, and the amount of absorbed co2 also increases . table 3. the results of 𝐂𝐎𝟐 loading of the third set of experiments for continuous process by using (mea=10% and dea=5%) as blended solution group gas flow l𝒎𝒊𝒏−𝟏 air flow l𝒉−𝟏 liquid flow l𝒎𝒊𝒏−𝟏 abso. time/min 𝑪𝑶𝟐 loading (mol 𝑪𝑶𝟐/mol amine) absor. capa. a/10 min 10 100 5 10 0.581 0.128 b/10 min 10 100 5 10 0.742 0.164 c/10 min 10 100 5 10 0.863 0.191 d/10 min 15 150 10 10 0.836 0.185 e/10 min 15 150 10 10 0.884 0.197 f/10 min 15 150 10 10 1.225 0.305 g/10 min 20 200 15 10 0.997 0.233 h/10 min 20 200 15 10 1.180 0.254 i/10 min 20 200 15 10 1.367 0.329 72 elaf thamer, salih rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 068–073 figure 4. comparison of the results obtained for 𝑪𝑶𝟐 loading capacity vs. reaction time for the tested aqueous amine solution 5.1. effect of 𝑪𝑶𝟐 loading on overall mass transfer coefficient kga: equation (6) show the calculation of kga for continuous process ,the results of kga for continuous process at 10% mea+ 5%dea, the overall mass transfer coefficient of the solutions was range between minimum and maximum value (0.010.04) 𝑆−1 figure 5comparison of the results obtained for 𝑪𝑶𝟐 loading capacity vs. reaction time for the tested aqueous amine solution (10%mea+5%dea) the effect co2 loading on overall mass transfer coefficient of fig. 5 ,it is obvious that an increase of co2loading in amine solutions leads to adecrease in the existing active amine concentration, which consequently decreases the overall mass transfer coefficient .this effect is mainly attributed to the amount of co2loading in the amine solution is high. where (mea+dea) blended amine solution was used , the mass transfer driving force from the gas phase to the liquid phase will decrease. 5.2 effect of liquid and gas flow rates on overall mass transfer coefficient( 𝑲𝑮𝒂) 5.1.1. for liquid flow rate : the influence of liquid flow rate on the overall mass transfer coefficient has been studied for a blended amine solution (10%mea+5%dea) for continuous process. the influence of the liquid flow rate on the overall mass transfer coefficient has been studied on the set 3 using blended amine solution (mea+dea) solution was of concentration by volume percent (v/v%) , 10%mea ,5% dea respectively . fig. 6 presents the evolution of kga in function of the time for various liquid flow rates. the obtained mass transfer coefficient after 10 minutes of experiment was (0.04 𝑺−𝟏 at flow rate 20 l/min. the first observation is that increasing of the liquid flow rate, the overall mass transfer coefficient also increase with increasing time ,and that opposite with circulation process . 5.1.2. for gas flow rate : one of the key parameters, which can affect the mass transfer performance, is the gas flow rate. many researchers showed that when the gas flow rate increased, kga increased as well. the blended amine solution was in the form of volume percent concentration 10%,5% respectively. fig. 6 presents the evolution of the overall mass transfer coefficient in function of the time for various gas flow rates. the kga was (0.04 𝑺 −𝟏) at gas flow 20 l/min ,and the air flow was 200 l/h which indicates that more 𝐶𝑂2,is absorbed at saturation step when more gas pass through the column. figure 6overall mass transfer in function of time for continuous processes (10% mea+ 5%dea) 6. conclusion the main objective of this study is to investigate the carbon dioxide absorption in bubble column reactor at different blended amine solution monoethanolamine (mea) and diethanolamine (dea) were used as solvent.to achieved this , it was necessary to calculation of the best overall mass transfer coefficient with the help of taguchi method as an experimental design, in order to reduce the large amount of experiments. this purpose was made using continuous process. the motivation of this thesis focuses on study the effect of all parameters {co_2 loading ,liquid flow rate , gas flow rate , absorption time} on (𝑘𝐺𝑎). this study showed that the increasing by the gas flow rate, the liquid flow rate, the 𝑘𝐺𝑎 values increased. also, increasing the 𝐶𝑂2 loading of amines lead to a 𝑘𝐺𝑎 decrease . 7. acknowledgment the authors gratefully acknowledge the support from university of al-qadisiyah, diwaniya – iraq. 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0 0.5 1 1.5 o v e ra ll m a ss t ra n sf e r co e ff ic ie n t k g a , 𝑆 (− 1 ) mol co2/mol amine co2 loading 0 0.01 0.02 0.03 0.04 0.05 0 2 4 6 8 10 12 absorption time/min 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 5 10 15 m o l c o 2 /m o l a m in e c o 2 l o a d in g absorption time/min elaf thamer, salih rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 068–073 73 references [1] h. m. s. al-maamary, h. a. kazem, and m. t. chaichan, “climate change: the game changer in the gulf cooperation council region,” renewable and sustainable energy reviews, vol. 76. elsevier ltd, pp. 555–576, 2017, doi: 10.1016/j.rser.2017.03.048. 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[13] c. m. ng, p. c. chen, and s. manickam, “green high-gravitational synthesis of silver nanoparticles using a rotating packed bed reactor (rpbr),” ind. eng. chem. res., vol. 51, no. 15, pp. 5375–5381, apr. 2012, doi: 10.1021/ie201795u. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٨ a study of the effect of impact loading on dsifs and crack propagation in plate dr. fathi a. alshamma ali fahad fahem university of baghdad, college of engineering university of al-qadisiya, college of engineering mechanical engineering department mechanical engineering department abstract in this work, a study of the effect of impact loading on dynamic crack propagation in thin and isotropic thick plates for two types material, stainless steel and aluminum, are investigated analytically and numerically to give a complete study of 3d crack growth of simple supported plate with internal crack at the center of plate. the dynamic stress intensity factor (dsifs), velocity of dynamic crack propagation and the deep of crack normal to the crack face for different angles from crack tip have been calculated when contact of a cylindrical impactor on isotopic plates is considered, to support the analytical result for dsifs with a numerical package result (ansys-10). this based on finite element method used to investigate the stress and the values of dynamic stress intensity factors at the crack tip by full transient dynamic analysis using 3d (element, solid-90). the results from airy stress function method gives good agreement with the results of ansys for long time duration in impact loading while the energy method is agreement with the ansys package for some time and then become limited. in addition, the dsifs and crack propagation velocity are increasing with angel from crack tip and velocity impact increasing. keywords: dynamic stress intensity factor, finite element analysis, velocity impact, crack angle, crack propagation. �������� ���� ��� ����� ��� ���� ��� ����� �� �� ����� � !� "��" . ��* �b 19bه �b%* �15 ا�2�a@ ا�(��ع. د � ا���1�9آ�، �� :� �1cاد � آ� � ا���1�9، �� :� ا�'�د� � ( ��( � �8�. ا�9 8�. ا���1�9 ا�( ��( � ���1 ا� ا�<=>� �'& 4 آ� ا���7ر ا�q7 �8 ا�pk�$t ا� l+�� وا�,�+�6 اo�cو@ و1+� �-�t��4* ا 2+n@ ��اء @�'+* و درا ا! ?@ ^^+�و�#� ���7�pk�$t� ثs9���1د اc8 ا� q7�آ� ��� ا 8 4� ��ء درا�)�c د�����أ و اc��#+�م �t �� وt'� وم����ا ����8 ا����دن ا�� o+,1 #�د�ا ���4.86+-�#���ة ا�q!cد ا�u *-��4,�ب ?@ ، �g,#��1 q7'� دي����ا q���ف اsا�� (q7��7ر ا��c آ� ��ا �� � � @��س ا�(�ا�� �yد-� �pk�$t ا�oو@ و1+�#� q7�ف ا وا�� -^ =o�ف اsوا�� q7�ا x!�� ، ة�u *-���� �+'+'���ا vk��#�ا ?�@? د (86+-�#��� ا�q!cد ا�#� 86+-�#���ة ا�q!cد ا�u *-��-د و�q!cا q+���� دة�����د �'& �t �� ا��#�y ا���c�1 د���� vk��� �-رز �#t 82s2 ا��1cد �-�ا�#��vk ا��8 @? ا���tل �'+�q آ�� -��ا��� 671* . = ف ا�q7 �1���'+* ا���#�-+86 ا����c�8 ا��6-* -,�< � t� ^+1 �� ا� ي ��q!sد -) ا�+!�-�t'� �+#-o�آ�د ا �ة ا د�� =�ل ���1+#�� ا��(�t� ^+1 q1 �� ا�(��l وا�#��vk ا���د�� . #��vk ا�� �دة� �gyوا �-�t�ة -^ ز-^ ا $��داد . آ�ن o� q7�ا���7ر ا ���ة ا�q!cد ا�� آ8 و� u *-��ان �t4s?@ y�m� ���wc�1 �-�t�ا �� .��o1دة ا�oوا�� -^ = ف ا�q7 و� al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٨٩ nomenclature a plate width b plate length d flexural rigidity of the plate dsif dynamic stress intensity factor ee 21 , young's modulus of steel cylinder and the plate ic g critical strain energy m equivalent mass po peak overload observed when zerot = p t )( total instantaneous over load r radius of the steel cylindrical s velocity of impacter thc. plate thickness crack deep correct factor length of crack 2,1 k effect stiffness m,n integer numbers from 1 to ∞. n parameter depended on properties of material p r readies of plastic zone pc r critical plastic zone u, v the length and width of the equivalent area ys σ yield stress σ 2,1 principles stresses β property characterizing take fixing =0.23 υ1,υ2 poisson ratio for the steel cylinder and the plate α angle of crack front o α decay factor, 2.0=oα (mario, 1980). α p principle angle of crack front ηξ , location of load introduction one of the fundamental requirements of any engineering structure is that it should not fail in service and much of the skill of the structural engineer lies in recognizing that there are several possible modes of failure and in guarding against them in his design (knott, 1976). in the recent years, the important increased to know the remaining service lifetime of mechanical parts that have a crack in it before that part retires from service. this interest increased after catastrophic failures in ships and airplane structures. in order to calculate the stresses around the crack tip, three common methods are introduced for calculating the crack propagation and stress intensity factor such as astress intensity factors (ki, kii, and kiii) associated with the three basic modes of fracture. bj-integral, this may be defined as a path-independent line integral that measures the strength of the singular stresses and strains near a crack tip. a o c c c o al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٠ cenergy release rate (g), which represents the amount of work associated with a crack opening or closure. impact loading model icontact loading when the plates impacted in their middle with steel cylindrical of radius (r) = 10 mm, weight = 75 gm, e = 206.843 g. pa and poisson's ratio = 0.3 at various impact velocities (8 m/s, 4 m/s, 2 m/s and 1 m/s). the static force caused from impact was calculated by the following eq.(1) (zukas,1982). ( ) 53 2 52 2 2 2 1 2 1 4 5 11 3 4                             − + − = m v ee r p o υυ (1) since the force that resulted from impact is now calculated, the stresses due to impact can be found by dividing it over the area of the contact of the cylinder to the plate in order to reduce the time of the numerical calculation. (timoshenko,1959) iiloading from impact velocity the total response of materials and structures to intense impulsive loading is quite complex because a effective time is very short (zukas,1982). the empirical form used to describe the impact load as )(t p in eq. (2). where the major part of energy is transmitted at contact time divided to two sections, first over load (positive phase) decreases to zero and second goes below zero (negative phase) within a short time as shown in figure (1) could be taken as (dharni,2005) eq. (2) represents the load on the plate from impacted at any time but not all loads in plate at this time. for calculated the total load in the plate using multiple-segment of trapezoidal rule for divided the time for equal segment in positive phase only (steven,1990). ( ) )/exp()/1( dodt ttttpop α−−= (2) iiiduration impact and stress in plate the maximum load ( )p t occurs at a time ( ottd 5.0= ) where ( ot ) is the impact duration as shown in eqs. (3), and (4), (zukas,1982). (3) (4) the load from impact for any time ( d tt ≤≤0 ) obtained from substitution eqs. (1) and (4) into eq. (2) gives the final form to calculated the loading with time eq.(5). 52 2/1 4 5 94.2           = mns t o od tt 5.0= al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩١ ( ) ( ) ( )                     −                     −=               5 2 5 2 5 3 5 2 4 5 47.1 2.0 exp 47.1 1 2 4 54 5 mns tt mns m s np t (5) the in plane stresses that caused from impact must be calculated in order to apply it on the crack faces. the following equations eqs. (6), (7) and (8)) are used in order to calculate the σx, σy and xy τ that caused in the plate due to impact (bairagi,1986). ( ) ( )υ π π ππ υ ππ σ 2 2 2 2 2 2 242 2 2.0 2 2 2 2 2 242 2 2.0 ,, 1 sinsin116 sinsin116 −                                     +             ⋅      −⋅⋅ −         +             ⋅      − − ⋅−=       −       − b n a m bu ne b n a m au me x mnd b ny a mx smn td t po mnd b ny a mx smn td t po thce td t td t tyx (6) ( ) ( )υ π π ππ υ ππ σ 2 2 2 2 2 2 242 2 2.0 2 2 2 2 2 242 2 2.0 ,, 1 sinsin116 sinsin116 −                                     +             ⋅      −⋅⋅ −         +             ⋅      − − ⋅−=       −       − b n a m au me b n a m bu ne y mnd b ny a mx smn td t po mnd b ny a mx smn td t po thce td t td t tyx (7) ( ) ( )                   −         +       ⋅      ⋅      − − ⋅⋅−= +       − 2 2 2 2 2 42 2.0 ,, 1 coscos1 16 b n a mu ne xy dabmn b ny m a mx smn td t po thce td t tyx πυ ππ τ (8) where       ⋅      ⋅      ⋅      = b nu a mu b n a m smn 2 sin 2 sinsinsin πππηπξ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٢ results and discussion since the in plane stresses due to low velocity impact are known, they are resolved into components because the crack angle sometimes is oblique. one of the components is perpendicular to the crack face while the other is parallel to it. the parallel component is equal to zero, leading the kii value due to impact is zero, while the perpendicular component causes the ki mode causing an increase in the resultant of ki mode that happens in the plate at the crack tip. figure (2) and figure (3) shows the impact force distribution in the center of plate and crack front respectively , for stainless steel plate of dimensions 100×100×4.5mm obtained numerically by ansys-10. the dsifs evaluation the (ki, kii, kiii) are a constant, which gives the magnitude of the elastic stress field; there are called the stress intensity factors. dimensional analysis chose that ki must be linearly related to stress and directly related to the square root of a characteristic length. when a higher initial ki means a higher initial crack driving force. the sif is divided to the two types depended on the crack growth. when the amount of unstable crack growth is very limited, the dynamic effect on stress intensity can be neglected. in this case, the dynamic stress intensity factor mast be calculated dynamic ki (wanhill,1989). there are three types of crack modes, depending on the loading condition (david,1989), the opening mode (dki), the shearing mode (dkii), and the tearing mode (dkiii), the first mode is the most widely mode that occurs, while the second and the third modes do not occur individually, they occur with combination with mode i. the third mode was neglected in this study because of its small value that can be neglected comparing to the values of the first and the second modes. eq.(9) is finely form to calculates the magnitude of dsifs on mode i . (9) where figure (4) and figure (5) shows the stress distribution in the crack front and tip respectively ,plate of dimensions 100×100×4.5mm made from stainless steel obtained numerically by ansys10. using eqs.(6-9) to calculated the principle stresses and dsifs. with this way, the dsifs were calculated for both the stainless steel and aluminum plates at variable crack angle and variable aspect ratios. figure (6-9) shows the dsifs (dki) and their relation with the crack angle and duration time for a plate of 100×100×4.5mm,crack 7×2 mm in dimensions and made from stainless steel. figure (10) and figure (11) shows the behavior of dki with the increase in deep of crack and aspect ratio when the impact velocity is 1m/s . ( ) 2 2 4 1 2 2 2 2 * 88 3 cossin co ao co ao coctki normal c ππ αα πσ +       + = pppnnormal αασασσσ sincoscos 2 2 11 +== al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٣ crack tip plasticity (dugdale model). dugdual's analysis assumes that all plastic deformation concentrates in a strip in front of the crack. this type of behavior does indeed occur for a number of materials, but certainly not for all. for applied dugdale theory eq.(10), assume of elastic-perfectly plastic behavior (giacomin,1996) 2 8        = ys p ki r σ π (10) if kiki c = then 2 8        = ys c pc ki r σ π ; if pcp rr ≥ the crack is propagation a care must be taken in calculating readies of plastic zone value for different impact velocity for determiner the area of crack propagation. figure (12-15) shows the plastic zone animation relation with the aspect ratio and duration time for a plate of 100×100×4.5mm,crack 7×2 mm in dimensions and made from stainless steel. model of crack growth fracture mechanics deals with the study of how a crack or flaw in a structure propagates under applied loads. it involves correlating analytical predictions of crack propagation and failure with experimental results or numerical solution. the analytical predictions are made by calculating fracture parameters such as stress intensity factors in the crack region, which was used to estimate crack growth rate. typically, the crack length increases with each application of some cyclic load, such as cabin pressurization-depressurization in an airplane. further, environmental conditions such as temperature, extensive exposure, or dynamic loading to irradiation can affect the fracture property of a given material (ansys,2005). some typical fracture growth may evolve are: istatic growth, this state happens in equilibrium condition of crack propagation (stably, slowly, controlled). iiquasi static growth, this state happens without kinetic-energy production, the potential energy will gradually approach zero since the fractured pieces obviously are free of stress. iiidynamic growth, this state happens with kinetic-energy production. the crack driving force is large that in quasi-static. the dynamic crack growth may be considered in terms of an energy balance. after initiation of energy which increases during crack growth. by the time, the crack has reached a length i a i.e. the total excess energy has converted to kinetic energy in crack tip (wanhill,1989). simple expression for the stored kinetic energy is obtainable from the opening displacement of the crack flanks as shown in eq. (11) get               −= • • normal normal ai aoe a σ σ ρ 1 (11) where = • normalσ ( )ppp t αασασ sincoscos 2 2 1 + ∂ ∂ in this section a comparison results obtained from eq. (11), with the reference (sheng,2004), which is illustrated in the appendix a. applied eq. (a-4) for one state only where this equation al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٤ depended on the energy release rate theory. when a stainless steel plate (100x100x4.5mm), is impacted by steel cylinder at velocity 2 and 8 m/s the crack velocity calculated by eq. (a-4) see figure (16), and compare the result with eq. (11). we noted the good agreement and the average rate error is decreasing when the velocity impact are increasing. figure (17-19), and figure (20) show the crack velocity relation with the aspect ratio and duration time for a plate of 100×100×4.5mm,crack 7×2 mm in dimensions and made from stainless steel. energy method when a plate element is acted by external loading, the internal fibers of the material body absorb energy in the form of the potential energy and as a result, the body shows deformed shape externally. on removal of the loads, the stored potential energy is converted to kinetic energy so that the body wholly or partially regains its original position or shape. the absorbed potential energy of the internal forces stored within the structural body is often termed as strain energy (se) oru , and its magnitude is equal to the work done due to the internal forces (in the opposite sense). the potential of the external force v is defined as the work done by the external force (in the opposite sense) during deformation between the initial and final position. the dynamic kinetic energy dke add to the plate from impacter is, ( 2 2 1 stmass impacter ⋅⋅ ) where the st is velocity of impacter during the time of impact. the total energy in plate 1 π is give by (bairagi,1986) eq.(12). dkevu ++=π 1 (12) or ( ) ( ) ( ) ( ) ( )2 .2 2222 1 2 14 8 1 tsmttw mn tabq ttabdw impmnnmmn +−+=π π βα (13) by impacting a flat plate when diameter of impacter is large compared to its thickness in a direction perpendicular to its surface, a plane wave can be generated. before the arrival of release waves from the edges of the plate, the center portion is in a confined state of one-dimensional or uniaxial strain (loya,2006). the total strain energy for uniaxial strain eq. (14) ( )( ) ( )υ υυ σ − −+ ⋅=π 1 211 2 1 2 2 e impacter (14) the total strain energy in eq. (13) sum as energy in eq. (14) i.e.( 21 π=π ) , solving for calculated normal stress. the energy method is very important for comparison, because depended it on summations of all energy inter the plate from impact, solving eq. (13), and eq.(14) for calculated the normal stress on crack faces, and compared with result from airy equation for st. steel plates (100x100x4.5mm) at difference velocity impact. draw the relation for this tow method, these results is display in figure (21-25) noted the energy in plates are given good agreement with the airy method but not for all time, because the energy translated from impact to plate not continues to all time, but it reach to constant value. in addition, noted when the impact velocity is increasing the result from energy method is increasing the exactitude. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٥ conclusions the major observation and conclusion from study dynamic analysis, simply supported stainless steel and aluminum cracked plated, under various impact velocities by cylindrical steel are listed as follow: 1. the results of dsifs and velocity of crack propagation obtained by the building of programs by fortran bower station-90, for impact loading. these results have been obtained by two different ways. first by using classical method, and secondly by energy method. these two ways is gives the some results with percentage error is lowest than (15%). 2. in the case of internal crack the values of dynamic stress intensity factors (dsifs), is depended on the depth of crack and angle of local (alpha). 3. the duration of time impact is decreasing when the velocity of impact is increasing, and when the young modulus is increasing the duration time decreasing i.e. the duration of time depended on the properties of material. 4. the crack propagation activity at location when maximum dsifs along the crack front. also the plastic area is large then compared with a critical plastic area (dugdale model). 5. the velocity of crack propagation in steel is larger than in aluminum because deferent by young modulus. 6. the velocity of crack propagation in plain stress is larger than in plain strain, i.e. the crack velocity is decreasing when thickness of plates is increasing. 7. the velocity of crack propagation is decreasing when the aspect ratio is increase. in addition, increasing velocity of crack when velocity impact increase, when deep of crack increase the crack velocity increasing. this behavior as applied for path material and plane stress and plane strain. 8. the strain energy method is applied for all velocity impact and gives good agreement when velocity impact increasing more than 20 m/s. where the percentage error for result between the airy method and energy about (13%). references • • • • • • • ansys release 10.0 documentation, 2005 a. jeffrey giacomin, "dynamic fracture toughness of polypropylene reinforced with cellulose fiber", 1996. broek, david, “the practical use of fracture mechanics”, kluwer academic publishers, 1989. h. l. ewalds, r. j. h. wanhill, "fracture mechanics", edward arnold, 1989. jonas a. zukas, theodore nicholas and hallock f. swift, "impact dynamics", john wiley & sons, inc., 1982. j. a. loya et .al ," determination of the dynamic stress intensity factor of a specimen under one-point bending from measurement of the load-point displacement", journal de physique iv-proceedings, 2006. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٦ • • • • • • j. f. knott, "fundamentals of fracture mechanics", butterworth group,1976. loke sworappa r. dharni," laminated architectural glass subjected to blast, impact loading", 2005. mario paz," structural dynamics", van nostrand reinhold company, 1980. n. k. bairagi," a text book of plate analysis", khanna publishers, 1986. sheng liu et al, "resistance to cracking of stretchable semiconductor: speed of crack propagation for varying energy release rate", materials research society, 2004 steven cherpy and raymond, "numerical method for engineers with applications"1990 s. timoshenko, s. woinowsky krieger, "theory of plates and shells", mcgraw-hill company, 1959. appendix a: speed of crack propagation for varying energy release rate. from reference (sheng,2004), a simulation equation to calculate the propagation velocity of successive crack as a function of energy release rate. the energy release g averaged over the advancing front of a semi-infinite crack is ( ) ( )βα συπ ⋅⋅ ⋅⋅− = g e h g 22 1 2 (a-1) where h is the plate thickness, σ is the stress in the plate normal to the crack line, and e and υ are the young modulus and poisson ratio of the plate, respectively. the function ( ) h l g ⋅ ⋅ = π βα 2 , (a-2) where s ehh l µ ⋅⋅ = where h is the substrate thickness, and s µ is the shear modulus of plate. putting the function (a-2) into (a-1), we obtain as energy release rate g. 2 2 1 σ µ υ ⋅ ⋅⋅− = s ehh e g (a-3) crack propagation velocity v as a function of energy release rate g was given, al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٧             −⋅= 1sinh ic g g vov β (a-4) figure (1) behavior of impact (dharni, 2005) figure (2) impact load in ansys figure (3) crack opening in ansys figure (4) stress distributed crack al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٨ 0.0e+00 5.0e+07 1.0e+08 1.5e+08 2.0e+08 2.5e+08 3.0e+08 3.5e+08 4.0e+08 0.e+00 2.e-06 4.e-06 6.e-06 duration of time sec. d y n a m ic s tr e e s i n tu n s e ty f a c to r s d s if ( p a .m ^ -. 5 ) alpha=0(calculated) alpha=0(ansys) alpha=45(calculated) alpha=90(calculated) figure (5) dsif’s in ansys figure (6) impact velocity 1 m/s 0.0e+00 5.0e+07 1.0e+08 1.5e+08 2.0e+08 2.5e+08 3.0e+08 3.5e+08 0.e+00 1.e-06 2.e-06 3.e-06 duration of time sec. d y n a m ic s tr e s s i n te n s it y f a c to r s d k i (p a . m ^ -. 5 ) alpha=0(calculated) alpha=0(ansys) alpha=45(calculated) alpha=90(calculated) 0.0e+00 5.0e+07 1.0e+08 1.5e+08 2.0e+08 2.5e+08 3.0e+08 3.5e+08 4.0e+08 0.0e+00 5.0e-07 1.0e-06 1.5e-06 duration of time sec. d y n a m ic s tr e s s i n te n s e ty f a c to r s d k i (p a . m ^ -. 5 ) alpha=0(calculated) alpha=0(ansys) alpha=45(calculated) alpha=90(calculated) figure (7) impact velocity 2 m/s figure (8) impact velocity 4 m/s al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٢٩٩ 0.0e+00 5.0e+07 1.0e+08 1.5e+08 2.0e+08 2.5e+08 3.0e+08 3.5e+08 4.0e+08 0.e+00 2.e-07 4.e-07 6.e-07 8.e-07 duration of time sec. d y n a k ic s tr e s s i n te n s e ty f a c to r s d k i (p a . m ^ -. 5 ) alpha=0(calculated) alpha=0(ansys) alpha=45(calculated) alpha=90(calculated) 0.0e+00 5.0e+07 1.0e+08 1.5e+08 2.0e+08 2.5e+08 3.0e+08 3.5e+08 0.e+00 2.e-06 4.e-06 6.e-06 8.e-06 duration of time sec. d y n a m ic s t r e e s i n t u n s it y f a c t o r s d s if ( p a . m ^ .5 ) deeb=1mm deeb=2mm deeb=3mm deeb=4mm deeb=5mm figure (9) impact velocity 8 m/s figure (10) impact velocity is 1m/s 0.0e+00 5.0e+07 1.0e+08 1.5e+08 2.0e+08 2.5e+08 3.0e+08 3.5e+08 0.e+00 2.e-06 4.e-06 6.e-06 8.e-06 duration of time sec. d y n a m ic s tr e s s i n te n s e ty f a c to r s d k i (p a . m ^ -. 5 ) ar=1(calculated) ar=1(ansys) ar=1.5(calculated) ar=2(calculated) ar=2.5(calculated) ar=3(calculated) ar=3(ansys) 0.0e+00 5.0e-03 1.0e-02 1.5e-02 2.0e-02 2.5e-02 3.0e-02 3.5e-02 4.0e-02 4.5e-02 0.0e+ 00 2.0e06 4.0e06 6.0e06 8.0e06 1.0e05 1.2e05 duration of time sec. p la s ti c z o n e m ar=1 ar=1.5 ar=2 ar=2.5 ar=3 dugdale theory figure (11) impact velocity is 1m/s figure (12) impact velocity is 1m/s al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٠٠ 0.0e+00 5.0e-03 1.0e-02 1.5e-02 2.0e-02 2.5e-02 3.0e-02 3.5e-02 4.0e-02 4.5e-02 0.0e+00 1.0e-06 2.0e-06 3.0e-06 4.0e-06 duration of time sec. p la s ti c z o n e m ar=1 ar=1.5 ar=2 ar=2.5 ar=3 dugdale theory 0.0e+00 1.0e-02 2.0e-02 3.0e-02 4.0e-02 5.0e-02 6.0e-02 7.0e-02 0.0e+00 4.0e-07 8.0e-07 1.2e-06 time sec. p la s ti c a re a ( m ) ar=1 ar=1.5 ar=2 ar=2.5 ar=3 dugdale model figure (13) impact velocity is 2m/s figure (14) impact velocity is 4m/s 0.0e+00 2.0e-02 4.0e-02 6.0e-02 8.0e-02 1.0e-01 1.2e-01 0.e+00 1.e-07 2.e-07 3.e-07 4.e-07 5.e-07 time sec. p la s ti c a re a ( m ) ar=1 ar=1.5 ar=2 ar=2.5 ar=3 dugdale model figure (15) impact velocity is 8m/s figure (16) velocity compared al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٠١ 0.0e+00 2.0e-01 4.0e-01 6.0e-01 8.0e-01 1.0e+00 1.2e+00 1.4e+00 1.6e+00 0.0e+00 2.0e-06 4.0e-06 6.0e-06 time sec. c r a c k v e lo c it y ( m /s ) ar=1 ar=1.5 ar=2 ar=2.5 ar=3 0.0e+00 2.0e-01 4.0e-01 6.0e-01 8.0e-01 1.0e+00 1.2e+00 0.0e+00 5.0e-07 1.0e-06 1.5e-06 2.0e-06 time sec. c ra c k v e lo c it y ( m /s ) ar=1 ar=1.5 ar=2 ar=2.5 ar=3 figure (17) velocity impact is 1 m/s figure ( 18) velocity impact is 2 m/s 0.0e+00 2.0e-01 4.0e-01 6.0e-01 8.0e-01 1.0e+00 1.2e+00 0.0e+00 5.0e-07 1.0e-06 1.5e-06 2.0e-06 time sec. c ra c k v e lo c it y ( m /s ) ar=1 ar=1.5 ar=2 ar=2.5 ar=3 0.0e+00 1.0e-01 2.0e-01 3.0e-01 4.0e-01 5.0e-01 6.0e-01 7.0e-01 8.0e-01 9.0e-01 1.0e+00 0.0e+00 5.0e-07 1.0e-06 1.5e-06 time sec. c ra c k v e lo c it y ( m /s ) ar=1 ar=1.5 ar=2 ar=2.5 ar=3 figure (19) velocity impact is 4 m/s figure (20) velocity impact is 8 m/s al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٠٢ 0.0e+00 5.0e+10 1.0e+11 1.5e+11 2.0e+11 2.5e+11 3.0e+11 3.5e+11 4.0e+11 4.5e+11 0.e+00 2.e-05 4.e-05 6.e-05 duration of time sec. s 1 n (d y n a m ic n o r m a l s tr e s s ) p a . energy method airy method 0.0e+00 1.0e+11 2.0e+11 3.0e+11 4.0e+11 5.0e+11 6.0e+11 7.0e+11 8.0e+11 9.0e+11 1.0e+12 0.e+00 1.e-05 2.e-05 3.e-05 4.e-05 5.e-05 6.e-05 duration of time sec. s 1 n ( d y n a m ic n o r m a l s tr e s s ) p a . energy method airy method figure (21) velocity of impact =1 m/s figure (22) velocity of impact =2 m/s 0.0e+00 5.0e+11 1.0e+12 1.5e+12 2.0e+12 2.5e+12 0.e+00 1.e-05 2.e-05 3.e-05 4.e-05 5.e-05 6.e-05 duration of time sec. s 1 n ( d y n a m ic n o r m a l s t r e s s ) p a . energy method airy method 0.e+00 1.e+12 2.e+12 3.e+12 4.e+12 5.e+12 6.e+12 0.e+00 1.e-05 2.e-05 3.e-05 4.e-05 5.e-05 6.e-05 duration of time sec. s 1 n ( d y n a m ic n o r m a l s tr e s s ) p a . energy method airy method figure (23) velocity of impact =4 m/s figure (24) velocity of impact =8 m/s al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٠٣ 0.0e+00 2.0e+12 4.0e+12 6.0e+12 8.0e+12 1.0e+13 1.2e+13 0.e+00 1.e-05 2.e-05 3.e-05 duration of time sec. s 1 n ( d y n a m ic n o r m a l s tr e s s ) p a . energy method ansys figure (25) velocity of impact =20 m/s article al-qadisiyah journal for engineering sciences 13 (2020) 253–261 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mushtaq76h@gmail.com (mushtaq i. hasan) https://doi.org/10.30772/qjes.v13i4.687 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. experimental investigation of mini-channel heat sink with nanoenhanced phase change materials mushtaq i. hasan a*, dhuha rasheed saber a a departmnt of mechanical engineering, university of thi-qar, thi-qar,iraq. a r t i c l e i n f o article history: received 24 august 2020 received in revised form 05 october 2020 accepted 05 october 2020 keywords: mini heat sink phase change material (pcm) nanoparticle nano-enhanced phase change material(nepcm) paraffin wax a b s t r a c t an experimental investigation is conducted to study the potential of enhancement cooling performance for mini channel heat sink by using different cooling mediums which are air, pure paraffin wax, and nanoenhanced phase change material (nepcm). paraffin wax used as phase change material (pcm) and mixed with three types of nanoparticles of alumina (al2o3 ) and titanium dioxide (tio2) to improve the thermal conductivity of pcm. volume fraction values for each type of nanoparticles are (0.1, 0.2, 0.3, 0.4, and 0.5)% which dispersed through pcm. a constant heat flux had been applied to the heat sink base with values (449, 963, 1839, and 4946)w/m2. the results showed enhancement in cooling performance when dispersion the nanoparticles through the pcm which mean reducing the temperature of heat sink base as compared with air and pure paraffin wax. the experimental results also indicated that the cooling performance enhancement of nepcm and reduction the time of melting process continue with increasing the concentrations of nanoparticles for all material types but any surplus addition may cause negative effect due to sedimentation. optimum cooling performance of mini heat sink is achieved with al2o3 –pcm then tio2-pcm as compared with air with percentage of temperature reduction of 23.306 and 22.069% respectively as compared to air. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction cooling of electronic devices had been formed a great challenge for many researchers because of the rising temperature of the central processor unit(cpu) which is the most direct reason to reduce the reliability of electronic devices. the high temperature of cpu formed approximately 55% from reasons of device failure , 20% due to vibration, 19% due to humidity, and 5% due to dust according to ojha [1]. there are many types of researches that performed experimentally and numerically to find out methods for enhancing heat transfer by using heat sink which absorbs the undesirable heat from cpu by conduction and then dissipated it to the ambient. phase change materials (pcm) can be considered as a promising material for cooling techniques due to having high specific heat, low volume changing during phase change, and high melting heat which allow it to absorb large amount from heat during phase change and then belong to the solid phase when dissipated this heat to the ambient. nanoparticles dispersion into the pcm to enhance the low thermal conductivity of it. nanoparticles have been contributed to uniform heat distribution within pcm which leads to reduce melting time and boundary layer thickness that meaning decreasing the heat sink thermal resistance and enhancement coefficient of heat transfer thus, increasing heat transfer rate. tuckerman and pease [2] found out and performed the concept of the micro-channel and studied the enhancement of heat transfer rate for this channel by forced fluid through it. they explored that the heat transfer rate increased by using micro-channel comparing with conventional channel. they also indicated that the heat transfer coefficient increased when a hydraulic diameter of micro-channel decrease. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i 254 mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 peles et al.[3] experimentally studied the thermal resistance of pin-fin micro-channel heat sink. discussed parameters that affected the total thermal resistance such as geometry and thermo-hydraulic parameter. the results indicated that thermal resistance of pin fin micro-channel heat sinks was lower than the micro-channel heat sink. they concluded that the heat transfer rate can be enhanced by using microscale pin fin heat sink. forced convection is a very effective heat transfer mode over micro pin fin heat sink. for microscale pins, the coefficient of heat transfer was very large and this lead to decrease fins efficiency. pin fins should be short to increase its efficiencies. tang et al. [4] experimentally studied the characteristic of flow for helium and nitrogen in stainless steel microtubes, fused silica microtubes, and fused silica square micro-channels. the findings indicated that friction factors showed a reasonable agreement with theoretical predictions of fused silica microtubes with diameters from 50 to 201µm and fused silica square channels with a hydraulic diameter ranging from 52 to 100µm. stainless steel tubes with a diameter (d=119-300µm) showed higher friction factor than theoretical results for tubes with conventional size. this difference between experimental and theoretical results occurred due to large relative surface roughness for stainless steel tubes. from the literature and this study, the gaseous flow is suggested to be laminar in the micro-channel with surface roughness below 1%. because of the compressibility effect, appositive friction factor deviation is observed from the conventional theory. the drawback in friction factor is observed due to the rarefaction and the obtained results explained that the smaller friction factor in fused silica micro-channel. kuravi [5] numerically investigated characteristics of the flow and heat transfer for phase change material slurry that flow into the micro-channels with applied constant heat power at the base of micro-channels. this study conducted by changing the type of base fluid, channel dimensions, nanoparticle concentrations, particle size, heat flux which applied on heat sink base, inlet temperature, and melting range for pcm. this study investigated the impact of particle distribution within pcm on micro-channel thermal performance. micro-channel dimensions which used in this study were 533µm height and101µm width with water as conventional fluid and n-octadecane as pcm. the focus of the study was on specifically manifold micro-channels. because the flow in microchannels is not fully develop in this case, the thermal performance of microchannels was not obtained as in conventional channels due to the large length of channels as compared with the length of micro-channels. the effect of particle distribution can be ignored in a numerical model for some cases. thermal performance of slurry depending on the inlet temperature of fluid, pcm purity, the heat power, the thermal conductivity of the base fluid. the results revealed that the heat transfer coefficient of water is larger than the water-based slurry at channel width is 100µm. for the same channel with a pure poly alpha olefin (pao) which has thermal conductivity equal to the pcm, the slurry heat transfer coefficient was higher than pure pao and with increased mass concentration, the heat transfer coefficient increased. ho et al. [6] experimentally investigated the heat transfer rate of the hybrid water suspension of alumina al2o3 nanoparticles and the microencapsulated of n-eicosane as phase change material (mepcm) and thermophysical properties of this slurry such as density, heat capacitance, thermal conductivity, and dynamic viscosity. the results revealed that increasing the fraction of al2o3 lead to improving the thermal conductivity and enhanced thermal performance. hasan et al. [7] numerically investigated the performance of micro-channel heat exchanger of counter flow type using nanofluid of ( al2o3water and cu-water) as a coolant. the volume fraction values of nanofluids (1, 2, 3, 4, and 5)%. the obtained results showed that enhancement thermal performance of counter flow micro-channel heat exchanger (cfmche) with nanofluid as a coolant with acceptable increasing in pressure drop because of using proper volume fraction of nanoparticles and ultrafine nanoparticles. at low flow rate, the findings also revealed that thermal performance of (cfmche) with nanofluid (cu-water and al2o3-water)is better than that with conventional fluid due to high value of thermal conductivity of nanofluid while for high volume flow rate, the cooling performance controlled by the volume flow rate and there was no effect of nanoparticles for absorbing an extra amount of heat. the results indicated that thermal performance of (cfmche) had been enhanced significantly by increasing thermal conductivity of nanofluid. amirtham et al. [8] implemented a numerical study to investigate the effect of addition alumina nanoparticles (al2o3) through paraffin wax that used as (pcm) with a pipe system of heat storage. both melting and freezing rate of paraffin wax have been enhanced by adding the nanoparticle. the freezing rates of nano-pcm was fastened by (28.1, 29.8, and 33.3)% for paraffin wax with (2, 5, and 10)% al2o3 nanoparticles respectively whereas melting rate was maximum enhanced 3.5% for paraffin wax with 2% al2o3, as compared to the pure paraffin wax case. interestingly, this result indicates that the volume fraction of nanoparticles is an important parameter that required considered to improve the performance of pcm in a system of thermal energy storage. hasan et al. [9] numerically studied the thermal performance for a micro pin-fin heat sink with three fin shapes (circular, triangular, and square) and microchannel un finned heat sink. heat transfer and flow had been studied with pure water as base fluid and nanofluids (al2o3-water and diamond-water) as coolants with volume fractions of (1, 2, 3, and 4)%. comparison of thermal and hydrodynamic characteristics for different cooling mediums and fin shapes (circular, triangular, and square) and micro-channel un finned heat sink. heat transfer and flow had been studied with pure water as base fluid and nanofluids (al2o3-water and diamond-water) as coolants with volume fractions of (1, 2, 3, and 4)%. comparison of thermal and heat hydrodynamic characteristics for different cooling mediums and fin shapes nomenclature ab heat sink base area (m 2) c volume fraction% cp specific heat ( j/kg.k) cwt mass fraction dnp diameter of nanoparticle (nm) h heat sink height (mm) hch channel height (mm) i electrical current (amp.) k thermal conductivity (w/m. k) l heat sink length (mm) mr melting range ( °c) q heat flux (w/m2) tc thermocouple tr temperature reduction% v voltage (volt) w heat sink width (mm) wch channel width (mm) greek symbols µ dynamic viscosity ( pa.s) λ latent heat of fusion ( kj/kg) ρ density ( kg/m3 ) mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 255 had been studied for the same value of reynold number which ranging from 100 to 900 to keep the flow in the laminar flow zone. the obtained results indicated that the cooling performance of nanofluid (diamond-water) is better comparing with nanofluid (al2o3-water). for all nanofluid types and fins geometries, the findings show enhancement heat transfer performance for heat sink with nanofluid compared with base fluid due to increasing thermal conductivity for base fluid by dispersion nanoparticles which increasing heat dissipation but this causing high pressure drop. the results also revealed that cooling performance of heat sink with circular pin-fin is best from other fin shapes and square pin-fin causing the highest pressure drop. altohamy et al. [10] experimentally studied the effect of dispersion nanoparticles of alumina(al2o3) through water on cooling storage performance. the experiments were conducted by using spherical capsules containing pure water firstly, then nanoparticles suspension through water (50 nm al2o3) as nepcm with concentration (0.5, 1, 1.5, and 2)% during the charging process. the obtained results revealed that dispersion of nanoparticle with all concentrations has been a significant effect on the thermal performance of phase change material (pcm) which leads to reducing charging time of all volumetric flow rates and the inlet temperature for heat transfer fluid (htf). the completing charging time reduced with the percentage of (32, 28, 18, and 12)% for htf inlet temperature -12°c and volume flow rates of 12, 10, 8, 6 lpm respectively. the results indicated also, the total time to complete the charging process at different htf volume flow rates will decrease with increasing the nanofluid concentration and volume flow rate. hasan [11] compared the cooling performance of micro-channel heat sink with gradually and suddenly expanded micro-channels at different expansion lengths and expansion ratios and heat sink with straight micro-channels. micro pin-fins for different shapes (triangular and square) had been studied to improve the heat sink cooling performance. effects of using nanofluids (diamondwater, cu-water, and al2o3-water) with volume fraction values (1, 2, 3, 4, and 5)% as cooling fluids on overall heat sink performance by comparing with pure water as base fluid. fvm used to solve governing equations of continuity, momentum, and energy. the results showed enhancement for the overall performance of the micro-channel heat sink (mhs) with decreasing the expansion length and increasing expansion ratio. diverging micro-channels gives lower modification as compared with the suddenly expanded micro-channel at the same expansion ratio. improving microchannel heat sink cooling performance with nanofluid compared with base fluid and nanofluid (cu-water) gives the best performance of heat transfer compared with the other two types of nanofluids studied. micro pin-fin enhanced overall performance of micro-channel heat sink for different shapes studied but square fins are the better than triangular. the result also revealed that the enhancement of heat transfer by using micro pinfins heat sink or expanded micro-channel heat sink is higher than the same heat sink with nanofluids. manikandan and rajan [12] experimentally investigated the reduction in specific heat which occurs as a result of dispersing of nanoparticle in the base fluid such as a mixture of waterpropylene glycol. this reduction could be removed by a co-addition surfactant encapsulated paraffin wax, to form hybrid nanofluid. a hybrid nanofluid contained paraffin wax which encapsulated by pluronic p-123(70-120nm diameter, with the concentration of (1-5wt.%) and 1% of sand nanoparticles volume fraction in propylene glycol-water mixture. the findings indicated that efficiency of encapsulated pcm was 84.4% as a comparison with conventional paraffin wax and with the increasing volume fraction of paraffin wax, the specific heat for hybrid nanofluid will enhance with percentage 9.1% for 5wt.% concentration of paraffin wax in hybrid nanofluid when compared with the mixture of propylene glycol-water. they concluded that the paraffin wax concentration (1wt.%) shows optimum thermophysical properties for the hybrid nanofluid such as viscosity, thermal conductivity, and heat capacitance. prabhu et al. [13] compared experimentally between thermal storage capacity for pure paraffin wax as base pcm and paraffin wax with nanoparticles which used with a shell and tube heat exchanger. the findings indicated that using of nanoparticle enhanced the thermal energy storage due to the impact of dispersion alumina (al2o3) nanoparticles through the phase change material (pcm) as compared with the pure paraffin wax. they also examined the effect of 0.833% concentration by volume of nanoparticle on solidification and melting process by comparing pure paraffin wax with nano-enhanced paraffin wax. they found that the time of melting and solidification will reduce 50% by using nanoparticles suspended into the paraffin wax. they found that the discharge efficiency enhancing 4% and the charging efficiency enhancing 6% when using nanoparticle of alumina (al2o3) with paraffin wax as compared with pure paraffin wax. arshad et al. [14] experimentally studied the effect of round pin-fin diameter of heat sinks on the electronic devices thermal management. input heat flux ranging from 1.6kw/m2 to 3.2 kw/m2 with step 0.4kw/m2. around pin-fin made from aluminium which considers as thermal conductivity enhancers (tces) and chosen with a diameter of 2mm, 3mm, and 4mm. paraffin used as pcm with a volume fraction of (0, 0.5, and1)% that poured into the heat sinks with various configurations of pin fin. un finned heat sink used to compare the cooling performance of pcm and (tces). the study analysed the cooling performance of heat sink filling with pcm to illustrate the influence of heat densities, pin-fin diameter, and volume fraction of pcm on heat capacity, thermal conductance, operation time enhancement, and latent heat phase. the experimental results revealed that a heat sink of 3mm pin fin diameter shows the best thermal performance. they concluded that the base temperature of heat sink decreased due to an increase in volume fraction and the operation time has maximum enhancement at the case with 3mm pin diameter to reach 60 °c or 70 °c at each input heat flux. maximum thermal conductance and heat capacity of o.57w/k and 3.1 kj/k respectively for around pin fin heat sink filling with pcm with 3mm pin diameter. for electronic devices, the passive cooling being more efficient at low input heat flux because of phase change of pcm occur during a prolonged time. the effects of working fluid inlet temperature, reynolds number, and mixture ratio of nanoparticles of al2o3-mwcnt/water hybrid nanofluid on enhancement of heat transfer coefficient are studied experimentally for mini channel heat sink by kumar and sarkar [15]. volume ratios of nanoparticles are (5:0, 4:1, 3:2, 2:3, 1:4, and 0:5). nusselt number, friction factor, pressure drop, and convective heat transfer coefficient increase by increasing fraction of mwcnt in working fluid. a maximum enhancement for convective heat transfer coefficient has been observed with mwcnt (5:0) hybrid nanofluid is 44.02% compared with water. but maximum pressure drop increased by 51.2% for mwcnt hybrid nano fluid over base fluid at mixing ratio of (5:0) mwcnt and inlet temperature of 20 °c. they concluded that nanofluid with different concentrations has better performance as compared with base fluid (di water) and optimum mixing ratio of al2o3 and mwcnt is 3:2.they also observed that inlet temperature of fluid has positive effect on heat transfer and negative effect on the pressure drop. in this paper, cooling performance of mini channel heat sink with various cooling mediums at different heat flux values has been investigated experimentally. 256 mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 2. experimental set up apparatus had been used for this study is shown in figure 1 which consists of a heat sink, heater, power supply, wool glass, thermocouples, a piece of copper, and data logger. a heat sink made from aluminium with dimensions (92×48×33) mm that involving sixteen channels, each channel with width wch= 2.375mm and height hch= 23mm as shown in figure 2. all sidewalls of the heat sink have been insulated by the glass wool and exposed to mixed free convection and radiation from the top only. the power supply provided the heat flux values which applied on the heat sink base. a copper piece has been used to mimic the electronic chip which adhesive with the heat sink base by using thermal paste from zinc oxide to get uniform heat flux. for all experiments the heat flux had been calculated from the following relationship: 𝑞 = 𝐼 × 𝑉 𝐴𝑏 (1) where i: electrical current (ampere). v: voltage (volt), ab: area of the heat sink base. q: heat flux (w/m2). and the temperature reduction has been calculated as 𝑇𝑅 = 𝑇𝑎𝑖𝑟−𝑇𝑝𝑐𝑚 𝑇𝑎𝑖𝑟 × 100% (2) where tr: temperature reduction, tair: heat sink base temperature with air, and tpcm: heat sink base temperature with paraffin wax. nine thermocouples of k-type with accuracy ˂400 °c (0.75% ± 2.5°c), 0.26 mm wire diameter and stainless steel probe had been distributed inside heat sink. five thermocouples located on the heat sink base for measuring the heat sink base temperature, three thermocouples located at a height from the base for measuring the fluid temperature and one thermocouple located outside the rig which measuring the ambient temperature as shown in ( table 1). all these thermocouples linked to the data logger to record its temperature. calibration of thermocouples had been conducted with thermometer by measuring the temperature of water to ensure the accuracy of thermocouple and the results show a 1% error. all experiments considered the ambient temperature approximately 20°c. data logger with 12 channels had been used to provide the time-temperature parameter (model: btm-4208sd) with accuracy (±0.4%+1°c), range (-50 to +999.9°c). it contained an sd card which recorded the temperatures at every 10 minutes as an excel sheet that displays on the laptop. table 1 locations of thermocouples in mm inside heat sink with (x, y, z) coordinates tc1 tc2 tc3 (12,0,23) (12,0,69) (36,0,23) tc4 tc5 tc6 (36,0,69) (24,0,46) (24,13,23) tc7 tc8 tc9 (24,13,46) (24,13,69) ambient figure 1 experimental set up. figure 2 mini heat sink. figure 3 electrical mixer. data logger power supply thermocouples mini heat sink heater y x z mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 257 3. preparation of nanoparticles-enhanced phase change material (nepcm) procedure in this study, the preparation of nepcm had been conducted by heating the required amount of paraffin wax with thermophysical properties as mentioned in table 2 until completed melting. the amount required of nanoparticle had been calculated from the following relationship which used to convert the volume fraction to mass fraction dhaidan et al. [16]. 𝐶 = 𝐶𝑤𝑡 𝜌𝑝𝑐𝑚 𝐶𝑤𝑡 𝜌𝑝𝑐𝑚 + (1 − 𝐶𝑤𝑡 )𝜌𝑛 (3) where c, cwt , 𝜌pcm , and 𝜌n are volume fraction, mass fraction, density of paraffin wax (kg/m3), and density of nanoparticle (kg/m3)respectively. then dispersion a suitable amount of nanoparticles through the paraffin wax with continue heating and moving the mixture until reach to the temperature (30°c) above the pcm melting temperature which has melting range (mr) (50-57°c) and latent heat (λ) (179.6 kj/kg). when the mixture temperature becomes 87°c dhaidan et al. [16], the mixture is mixed by using the electrical blender as shown in figure 3 for 30 minutes until getting emulsion to retard any possible sedimentation and agglomeration. table 2 thermophysical properties of materials in this study [10, 17, 18]. material type ρ (kg/m3) cp (j/kg.k) k (w/m.k) µ (pa. s) dn (nm) air 1.2 1006 0.0242 1.789e-5 paraffin wax 773 2300 0.215 0.00063 alumina (al2o3) 3600 773 36 80 titanium dioxide (tio2) 4156 692 8.4 25 4. experimental procedure 4.1 experiments of air experiments of air as coolant can be summarized by applying the heat load on the heat sink base from heater along the experiment period for all heat flux studied values. 4.2 experiments of pure pcm experiments of pure pcm have been conducted by melting a suitable amount of pcm that filling heat sink. then pouring melting pcm in the heat sink which heating to reach a temperature above the melting range of pcm. 4.3 experiments of nepcm during the process of preparing nepcm, the heater must be operated to heat the heat sink base at a temperature above that the temperature for nepcm to prevent the formation of bubbles or voids within the nepcm and then pouring the required amount of pcm and nepcm inside the heat sink. both the pure pcm and nepcm had been remained in the heat sink until they reach ambient temperature to start an experiment. for all types of coolants, measuring the heat sink base temperature by using thermocouples linked to the data logger to record the temperature on the sd card every 600 sec for 7200 sec. these thermocouples distributed on the base and at a given height to measure the temperature of the coolants. for every value of volume fraction of nepcm and heat flux, these steps have been repeated. 5. results and discussion all experimental investigations had been carried out with air as base cooling medium, pure paraffin wax, nanoparticles-enhanced phase change material (nepcm) with al2o3, and tio2 nanoparticles at various volume fractions of (0.1%, 0.2%, 0.3%, 0.4%, 0.5%) and different heat flux values (449w/m2, 963 w/m2, 1839 w/m2, 4946 w/m2). the ambient temperature was approximately maintained at 20°c at all experiments. the experiments had been conducted on the heat sink to find the best material which showed the best efficiency for cooling electronic devices. variation of the base temperature of a heat sink versus time for pcm and air for all values of heat flux mentioned in this study is elucidated in figure 4. this figure explained that the base temperature increased with time for all values of heat flux and with increased heat flux due to increase the amount of generated heat at the heat sink base. at all values of heat flux, there is a reduction in temperature by using paraffin wax as a cooling medium compared with that for air as a result of absorbing an extra amount of heat by paraffin wax during melting process as latent heat. figure 5 presents the variation of temperature reduction for the case of paraffin wax compared with air versus time at different values for heat flux. from this figure, it can be observed that there is a considerable reduction in the base temperature with paraffin wax as compared with air because of absorbing an extra amount of heat as latent heat during phase change process as explained before. also, it can be noted that the peak values of temperature reduction happened at different times for different values of heat flux because the melting process occurred at a certain melting temperature range and increasing the value of heat flux cause increasing in paraffin wax temperature which makes the melting process started earlier. the maximum value of temperature reduction occurred at maximum heat flux which reaches 19.27 %. variation of heat sink base temperature versus time at same volume fraction 0.1% and all heat flux values heat of (449, 963, 1839, and 4946 w/m2) for all cooling medium types used in this study illustrated in figures (6, 7, 8, and 9). these figures illustrated that the heat sink base temperature for all types of nanoparticles-enhanced pcm is lowest than air and pure pcm due to a higher value of thermal conductivity and density of nanoparticle-enhanced pcm. the heat sink base temperature with al2o3-pcm is lower than tio2pcm due to the al2o3-pcm has a higher value of thermal conductivity and specific heat compared with tio2-pcm. heat sink cooling performance with nepcm for all types of nano-enhanced pcm (al2o3-pcm and tio2pcm) is most efficient from the air and pure pcm because of rising thermal conductivity of pcm when dispersing the nanoparticles through it. these nanoparticles have been contributed to a uniform distribution of the temperature through pcm which causing reduction thickness of the boundary layer hence, reducing thermal resistance of heat sink which leads to enhancement heat transfer coefficient thus, increasing heat transfer rate. figure 10 indicates the base temperature variation with volume concentration for tio2 at different values of heat flux. this figure shows obviously that the heat sink base temperature reduced by increasing the concentration of tio2 at heat flux values (449w/m 2 and 963 w/m2) and start with rising at higher values of heat flux (1839 w/m2 and 4946 w/m2) and increasing the concentration of tio2 which may causing sedimentation that forming additional thermal resistance. the variation of the heat sink base temperature with concentrations of al2o3 at various values for heat flux is elucidated in figure11. at all heat flux value which applied to the heat sink base, there was a reduction in a heat sink base temperature until 258 mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 0 2 4 6 8 10 12 14 16 18 20 0 2000 4000 6000 8000 b a se t e m p e ra tu re r e d u c ti o n % time (sec.) figure 5 variation of base temperature reduction between air and pcm with time at constant heat flux. heat flux=449 w/m^2 heat flux=963 w/m^2 heat flux=1839 w/m^2 heat flux=4946 w/m^2 20 30 40 50 60 70 80 90 100 0 2000 4000 6000 8000 b a se t e m p e ra tu re ( °c ) time (sec.) figure 4 variation of base temperature with time at constant heat flux for air and pcm. air at heat flux=449 w/m^2 pcm at heat flux=449 w/m^2 air at heat flux=963 w/m^2 pcm at heat flux=963 w/m^2 air at heat flux =1839 w/m^2 pcm at heat flux=1839 w/m^2 air at heat flux=4946 w/m^2 20 25 30 35 40 45 50 55 60 65 70 0 1000 2000 3000 4000 5000 6000 7000 8000 b a se t e m p e ra tu re ( °c ) time (sec.) figure 6 variation of base temperature with time at heat flux=449 w/m2 and volume fraction=0.1%. air pcm tio2-pcm al2o3-pcm 20 30 40 50 60 70 80 0 1000 2000 3000 4000 5000 6000 7000 8000 b a se t e m p e ra tu re (° c ) time (sec.) figure 7 variation of base temperature with time at heat flux=963w/m2 and volume fraction=0.1%. air pcm tio2-pcm al2o3-pcm concentration (0.2%) then begin to rise with increasing concentration and heat flux value which may occur because of the large size of al2o3 nanoparticle as compared with the size of tio2 which used in this study. this large size of the nanoparticle may cause early sedimentation. variation of heat sink base temperature with volume fraction for all nanoparticles materials and the same value of heat flux is illustrated in figure12. this figure revealed that the heat sink base temperature with tio2-pcm was the higher than al2o3-pcm respectively until 0.2% volume fraction because of the theromphysical properties of al2o3-pcm is more efficient than tio2pcm. heat sink base temperature with al2o3-pcm begin to rise for all remain concentrations because of large size of nanoparticles which cause earlier sedimentation. figure 13 shows variation of heat sink base temperature for all values of concentration and all types of nano-pcm at constant heat power. this figure indicated that the cooling performance of heat sink with al2o3-pcm is better than tio2-pcm but by increasing volume fraction of al2o3-pcm, the base temperature begins to rise due to occur sedimentation as mentioned previously. figure 14 illustrates the impact of increasing concentration of all nano-enhanced pcm on the heat sink base temperature at the same heat flux. this figure explained that the heat sink base temperature with al2o3-pcm is lower than tio2-pcm at 1839 w/m2 and concentration of 0.2%. at this same heat flux value and increasing volume fraction to 0.3%, the heat sink base temperature with al2o3-pcm will rise due to the effect of large size of al2o3 nanoparticles. while the heat sink base temperature with tio2-pcm will begin to rise at o.4% due to difference in nanoparticles size between them. the variation of the heat sink base temperature with all values of concentrations for different types of nano-enhanced pcm at the highest value of heat flux elucidated in figure 15. this figure indicated that the heat sink base temperature reduced with increased concentration until reach a certain value for each type of nano-pcm and then begin to rise due to sedimentation which occurring because of increasing the value of concentration and heat flux which forming additional thermal resistance on the base of the heat sink which leads to reduced heat transfer rate. the heat sink base temperature with al2o3-pcm showed minimum heat sink base temperature as compared with tio2-pcm due it has better thermophysical properties than tio2-pcm. mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 259 20 30 40 50 60 70 80 90 0 1000 2000 3000 4000 5000 6000 7000 8000 b a se t e m p e ra tu re ( °c ) time ( sec.) figure 8 variation of base tmperature with time at heat flux=1839 w/m2 and volume fraction=0.1%. air pcm tio2-pcm al2o3-pcm 20 30 40 50 60 70 80 90 100 0 1000 2000 3000 4000 5000 6000 7000 8000 b a se te m p e ra tu re (° c ) time (sec.) figure 9 variation of base temperature with time at heat flux=4946w/m2 and volume fraction=0.1%. air pcm tio2-pcm al2o3-pcm 40 50 60 70 80 90 0 0.2 0.4 0.6 b a se t e m p e ra tu re ( °c ) volume fraction % figure 10 variation of base temperature with volume fraction of titanium dioxide (tio2) at constant heat flux. heat flux=449 w/m^2 heat flux=963 w/m^2 heat flux=1839 w/m^2 heat flux=4946 w/m^2 40 50 60 70 80 90 100 0 0.1 0.2 0.3 0.4 0.5 0.6 b a se t e m p e ra tu re ( ° c ) volume fraction %. figure 11 variation of base temperature with volume fraction of alumina (al2o3) at constant heat flux. heat flux=449 w/m^2 heat flux=963 w/m^2 heat flux=1839 w/m^2 heat flux=4946 w/m^2 45 47 49 51 53 55 57 59 61 63 65 0 0.1 0.2 0.3 0.4 0.5 0.6 b a se t e m p e ra tu re ( °c ) volume fraction% figure 12 variation of base temperature with volume fraction at heat flux=449 w/m2. tio2-pcm al2o3-pcm 50 55 60 65 70 75 80 0 0.1 0.2 0.3 0.4 0.5 0.6 b a se t e m p e ra tu re ( °c ) volume fraction% figure 13 variation of base temperature with volume fraction at heat flux=963 w/m2. tio2-pcm al2o3-pcm 260 mushtaq ismael hasan , dhuha rasheed saber /al-qadisiyah journal for engineering sciences 13 (2020) 253–261 60 65 70 75 80 85 90 95 100 0 0.2 0.4 0.6 b a se t e m p e ra tu re ( °c ) volume fraction%. figure 14 variation of base temperature with volume fraction at heat flux=1839 w/m2. tio2-pcm al2o3-pcm 70 75 80 85 90 95 100 0 0.1 0.2 0.3 0.4 0.5 0.6 b a se t e m p e ra tu re (° c ) volume fraction % figure 15 variation of base temperature with volume fraction at heat flux=4946 w/m2. tio2-pcm al2o3-pcm 6. conclusions the present experimental study investigated the heat sink cooling performance with different cooling mediums such as air, pure paraffin wax, and nanoparticles enhanced phase change materials for electronics cooling. the impact of different volume fractions (0.1%, 0.2%, 0.3%, 0.4%, and 0.5)% of nanoparticles (al2o3 and tio2) and heat flux values(449, 963, 1839 and 4946) w/m2 on cooling performance is studied. air had been considered as base fluid to compare the performance of other cooling mediums with it. the main conclusions presented as following: 1. cooling performance of heat sink with pcm is more efficient than air at all heat flux values and a reduction of the heat sink base temperature is approximately 19.276% for maximum value of heat flux. 2. at all heat flux values and for all nanoparticle types, the heat sink cooling performance with nepcm shows a great enhancement as compared with air and pure paraffin wax. 3. the results revealed that the cooling performance of mini heat sink with alumina (al2o3 ) nanoparticles-pcm is better comparing with titanium dioxide (tio2)-pcm that represented with a percentage of temperature reduction of 23.306 and 22.069% respectively as compared to air. 4. the findings indicated that the melting and solidification time will decrease with increasing the amount of heat power and the concentration by volume of all materials which contribute to distribute temperature distribute temperature uniformly. 5. the experimental results elucidated that by increasing dispersion of volume fraction of all nanoparticle material types, the cooling performance enhancement is increased at all values of heat flux but the excess addition of nanoparticles will lead to increase viscosity that decreased heat transfer rate and giving negative effect. 6. the experimental results of the present study indicated that dispersing a suitable volume fraction of nanoparticles in pure pcm showed a high potential for enhancing the heat transfer characteristics of cooling mediums. references [1] shakuntala ojha, "cfd analysis on forced convection cooling of electronic chips" , national institute of technology. rourkela 2009, a thesis for the degree of master of technology (research) in mechanical engineering. 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"nano enhanced phase change material for thermal energy storage application". international research journal of engineering and technology (irjet), vol. 5, pp. 2395-0056-0072, 2018. [14] adeel arshad, hafiz muhammad ali, shahab khushnood, and mark jabbal, "experimental investigation of pcm based round pin-fin heat sinks for thermal management of electronics: effect of pin-fin diameter", international journal of heat and mass transfer, vol. 117, pp. 861-872, 2018. [15] vivek kumar and jahar sarkar, "particle ratio optimization of al2o3 mwcnt hybrid nanofluid in minichannel heat sink for best hydrothermal performance", journal of applied thermal engineering, vol. 165, 25 january, 114546,2020. 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", journal of engineering science and technology review, vol. 9, no.4 , pp. 26-386, 2016. article al-qadisiyah journalfor engineering sciences13 (2020) 200–206 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hanankarkoosh@gmail.com (hanan a.ibraheem) https://doi.org/10.30772/qjes.v13i3.706 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. use of cement kiln dust to remove copper from simulated wastewater using the response surface methodology hanan a. ibraheem a*, husham m.al.tameemi a a university of al-qadisiyah, qadisiyah, iraq a r t i c l e i n f o article history: received 13 june 2020 received in revised form 20 august 2020 accepted 30 august 2020 keywords: ckd wastewater copper removal response surface methodology a b s t r a c t copper removal from simulated wastewater was achieved using cement kiln dust (ckd) as adsorbent. the effects of contact time, ph, initial copper ion concentration, rotational speed, and cement kiln dust (ckd) amount were studied. the best operating conditions were determined by applying a response surface methodology (rsm). the results showed that the copper concentration has the main effect on the efficiency of copper removal followed by time, shaking rate, dosage of cement kiln dust, and ph. the best operating conditions were found to have a ph value of 8, contact time 90 minutes, shaking rate of 300 rpm, copper ion concentration 20 ppm, and a quantity of ckd equivalent to 35 g / l. based on this optimum condition, 99 % of the efficiency of copper removal was achieved. ©2020 university of al-qadisiyah. all rights reserved. 1. introduction due to the increase in human activities represented by factories, mining operations, and household needs, there is a growing demand for water usage and, at the same time, there has been an increase in the output of wastewater in general, especially industrial wastewater resulting from the production processes. this water is charged with many pollutants, in particular pollutants represented by inorganic materials with heavy metals such as copper. copper is considered as the most dangerous pollutant in the water among other inorganic pollutants because it may cause many diseases such as cancer as can be accumulated inside the bodies of living organisms [1, 2]. although copper is important to the body of the living organism, but the increase of its concentration in water above 3.0 mg / l causes liver cirrhosis, brain necrosis, and kidney damage [3, 4]; therefore, scientists resorted to finding ways to get rid of these minerals and address the problem of water pollution bailey et al. [5]. several methods have been used to remove copper, including electrodeposition, adsorption, reverse osmosis, etc. [5-9], but these methods were expensive, not highly efficient; therefore, the researchers continued their attempts to find economical and highly efficient methods by using the materials available in the environment. recently, adsorption was used by many authors, and an inexpensive material such as cement kiln dust (ckd) as a sorbent. ckd is a byproduct of cement manufacturing operations which has a basic property and its particles size very small mustafa et al. [10]. its presence causes environmental pollution because it affects a person's respiratory system. it is used in many processes, including soil stabilization rahman et al. [11], the production of fertilizers and building materials, and as an absorbent [1215]. the present research aims to investigate the capacity of the ckd generated locally as a pipette to extract copper from wastewater. to obtain optimum operating conditions, for the response surface methodology, has been adopted. http://qu.edu.iq/ mailto:hanankarkoosh@gmail.com%20(hanan https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ hanan a. ibraheem, husham m. al.tameemi /al-qadisiyah journalfor engineering sciences13 (2020) 200–206 201 2. materials and methods 2.1 ckd characterization a quantity of 2kg of ckd was taken from al-duh cement factory located south of al-muthanna governorate. the material was dried in a laboratory oven at a temperature of 100 ºc. xrd and edx examination were performed in the laboratories of the ministry of science and technology / materials research department in baghdad using an analyzer spectrometer (a philips x-ray diffraction (equipment model pw/1710 with monochromatic 2009)). 2.2. preparation of copper solution copper sulfate (cuso4.5h2o) was used to prepare the copper ions solution at concentrations (20, 60, and 100 ppm) by dissolving the appropriate amount in 400 ml of distilled water. then adjust the ph of the prepared solution using 0.1m naoh and/or 0.1m hcl to (2, 5, and 8) ph. after that, the required amount of ckd was added at concentrations of (5, 20, and 35) g / l to the copper solution and then shake the solution at a rate of different rotations (100, 200, and 300 rpm) and different times (30, 60 and 90 minutes). after the adsorption process was completed, the solution was filtered and a sample (5 ml) was taken to determine the concentration of copper residue with the atomic absorption spectrometer (japan, 2002). all experiments were conducted at room temperature, hence average values were considered for data analysis. the copper removal efficiency (r %) by using ckd was calculated according to the following formula (eq. 1) r%=(c0-c)/c0*100 (1) where c0 is the initial concentration of the copper solution and c is that the final concentration of the copper solution. 2.3 design of experiments the relationship between a process response and its variables will be determined by applying a group of mathematical and statistical techniques adopted by rsm bezerra et al. [16]. during this study, the 3-level 5-factor box–behnken experimental designs are implemented to verification and check the variables that influenced the removal of copper from simulated wastewater. initial copper ion concentration (x1) ckd dosage (g/l) (x2), shaking rate (rpm) (x3), ph value(x4), and contact time (min) (x5) were taken as process variables, while the efficiency of copper removal was taken as a response. the scales of process variables were coded as -1 (low level), 0 (middle or central point), and 1 (high level) evans et al. [17]. table 1 illustrates the method variables with their chosen levels. box–behnken improves designs to urge the acceptable quadratic model with the desired statistical properties by using only an element of the runs needed for a 3level factorial huiping et al. [18]. the number of runs (n) needed for performing of box–behnken design will be determined by the subsequent equation [2]: n =2k (k-1) + cp (2) where k is the number of process variables and cp is the reiterated number of the central point. in this work, forty six runs were conducted to evaluating the effects of the process variables on the copper removal efficiency. table 2 illustrates the box–behnken design (bbd) proposed for the present research. a second order polynomial model can be adopted based on bbd were fitting the interaction terms with the experimental data can be described by the following equation [3]: y= a0+ ∑ai xi+ ∑aii xi2+ ∑aij xi xj (3) where y represents the variable (re), i and j are the index numbers for patterns, a0 is intercept term, x1, x2 … xk are the method variables (independent variables) in coded form. aiis the first-order (linear) main effect, aii second-order main effect, and aij is that the interaction effect. analysis of variance was performed then the parametric statistic (r2) was estimated to verify the goodness of model fit. nomenclature ai the first-class(linear) major effect s standard error of mean aii second-class major effect k number of process variables aij the interaction effect y represents the dependent variable (re) ao the code of intercept se standard error of the regression bbd box–behnken design n number of runs ckd cement kiln dust cp reiterated number of the central point cu copper ci confidence interval t time, s anova analysis of variance x1 concentration of copper , ppm pi prediction interval x1 coded value of copper concentration dof degree of freedom x2 concentration of ckd ,g/l adj. ss adjusted sum of the square x2 coded value of ckd concentration d desirability function x3 shaking rate, rpm adj. ms adjusted mean of the square x4 ph seq. ss sum of square x3 coded value of shaking rate adj. r2 adjusted coefficient of multiple correlation x4 coded value of ph pred. r2 predicted multiple correlation coefficient x5 contact time, min cr. % percentage contribution for each parameter x5 coded value of contact time re removal efficiency (%) 202 hanan a. ibraheem, husham m. al.tameemi/al-qadisiyah journalfor engineering sciences13 (2020) 200–206 table 1. process variables with their level for copper removal process parameters range in box–behnken design coded levels low(-1) middle(0) high (+1) x1initial conc. (ppm) 20 60 100 x2ckd dosage(g/l) 5 20 35 x3shaking rate(rpm) 100 200 300 x4-ph value 2 5 8 x5-contact time(min) 30 60 90 table 2 .boxbehnken experimental design coded value in it ia l c o n c . (p p m ) c k d d o sa g e ( g /l ) s h a k in g r a te ( r p m ) p h c o n ta c t ti m e ( m in ) run b lo c k s x1 x2 x3 x4 x5 1 1 11 0 0 0 20 35 200 5 60 2 1 0 1 10 0 60 35 100 5 60 3 1 0 1 0 0 1 60 35 200 5 90 4 1 0 1 0 10 60 35 200 2 60 5 1 0 0 1 0 160 20 300 5 30 6 1 1 0 1 0 0 100 20 300 5 60 7 1 0 0 0 1 160 20 200 8 30 8 1 0 0 1 10 60 20 300 2 60 9 1 0 0 0 0 0 60 20 200 5 60 10 1 0 10 10 60 5 200 2 60 11 1 0 0 0 11 60 20 200 2 90 12 1 10 10 0 20 20 100 5 60 13 1 0 0 1 1 0 60 20 300 8 60 14 1 0 0 1 0 1 60 20 300 5 90 15 1 10 0 10 20 20 200 2 60 16 1 0 0 0 1160 20 200 2 30 17 1 0 0 10 160 20 100 5 30 18 1 10 0 1 0 20 20 200 8 60 19 1 1 0 0 0 1100 20 200 5 30 20 1 0 1 0 0 160 35 200 5 30 21 1 0 0 0 0 0 60 20 200 5 60 22 1 0 11 0 0 60 5 300 5 60 23 1 10 1 0 0 20 20 300 5 60 24 1 0 0 0 0 0 60 20 200 5 60 25 1 0 0 0 0 0 60 20 200 5 60 26 1 0 0 11 0 60 20 100 8 60 27 1 0 1 0 1 0 60 35 200 8 60 28 1 0 1 1 0 0 60 35 300 5 60 29 1 1 0 0 1 0 100 20 200 8 60 30 1 10 0 0 1 20 20 200 5 90 31 1 10 0 0 120 20 200 5 30 32 1 1 0 0 10 100 20 200 2 60 33 1 0 10 0 160 5 200 5 30 34 1 1 0 10 0 100 20 100 5 60 35 1 0 10 0 1 60 5 200 5 90 36 1 110 0 0 20 5 200 5 60 37 1 0 10 1 0 60 5 200 8 60 38 1 0 0 110 60 20 100 2 60 39 1 0 0 0 0 0 60 20 200 5 60 40 1 1 1 0 0 0 100 35 200 5 60 41 1 0 0 10 1 60 20 100 5 90 42 1 1 0 0 0 1 100 20 200 5 90 43 1 0 110 0 60 5 100 5 60 44 1 0 0 0 0 0 60 20 200 5 60 45 1 1 10 0 0 100 5 200 5 60 46 1 0 0 0 1 1 60 20 200 8 90 3. results and discussion 3.1. ckd properties xrd analysis of ckd was carried out in the target was copper (λ = 1.5406 a°) at 40 kv, 30 ma, and the scanning speed was 5 ◦ min−1. the reflection peaks between 2θ =5 ◦ and 80 ◦ , corresponding spacing (d, a°), present time (0.6 s) and relative intensities (i/io) were obtained table 3. table 3. the chemical composition of ckd components cao sio2 so3 k2o al2o3 fe2o3 mgo l.o.i average % 47.81 17.3 11.98 4.9 3.7 2.6 2.5 9.21 figure 1. xrd for ckd 3.2 statistical analysis statistical approaches like rsm are employed to maximize the assembly of a special substance by optimization of operational factors. in contrast to traditional methods, the interaction among process variables is determined by statistical techniques.46 experiments were performed with different variables of the process in different groups to determine their effect on the removal ratios and the knowledge of the optimization between them. table 4 shows the removal values for each experiment. the current and expected efficiencies are included in this table. it is interesting to note that the copper removal efficiency was changed from 35.59 to 100%, upon approval of the experimental design. the minitab-17 program is used to analyze the results of the copper removal efficiency as a pilot relationship between the copper removal efficiency and process variables were formulated through the quadratic model of the removal efficiency copper (re) in terms of encoded units for process variables: re% = 148.0 1.599 x1 0.515 x2 0.091 x3 +2.17 x41.173x5+ 0.00623 x12+ 0.00434 x22+ 0.000259 x32 0.080 x42 +0.00986 x52+0.00798 x1 x2+ 0.000096 x1 x3 +0.0041 x1 x4 + 0.00123 x1 x5 0.00060 x2 x3+ 0.0816 x2 x4 + 0.00343 x2 x5+ 0.00162 x3 x4+ 0.000765 x3 x5-0.0162x4x5 (4) equation (4) shows the effect of removal efficiency with the variables (squared and linear). increasing efficiency values increase with increasing values of positive coefficients depending on the laboratory scale, whereas. hanan a. ibraheem, husham m. al.tameemi /al-qadisiyah journalfor engineering sciences13 (2020) 200–206 203 table 4. the experimental results of "box–behnken design" for the copper removal r u n b lo c k s in it ia l c o n c . c k d d o sa g e s h a k in g r a te p h c o n ta c t ti m e re% actual prediction 1 1 20 35 200 5 60 97.03 91.90 2 1 60 35 100 5 60 58.76 61.07 3 1 60 35 200 5 90 79.73 80.74 4 1 60 35 200 2 60 53.46 58.03 5 1 60 20 300 5 30 68.21 66.30 6 1 100 20 300 5 60 54.64 53.67 7 1 60 20 200 8 30 69.49 64.74 8 1 60 20 300 2 60 57.29 61.26 9 1 60 20 200 5 60 57.83 57.88 10 1 60 5 200 2 60 52.37 50.24 11 1 60 20 200 2 90 74.31 70.23 12 1 20 20 100 5 60 91.2 87.96 13 1 60 20 300 8 60 65.83 70.22 14 1 60 20 300 5 90 87.76 84.37 15 1 20 20 200 2 60 89.99 86.76 16 1 60 20 200 2 30 55.69 53.83 17 1 60 20 100 5 30 60.26 58.89 18 1 20 20 200 8 60 95.15 93.77 19 1 100 20 200 5 30 39.31 45.36 20 1 60 35 200 5 30 63.5 64.17 21 1 60 20 200 5 60 57.98 57.87 22 1 60 5 300 5 60 65.98 63.61 23 1 20 20 300 5 60 100 99.19 24 1 60 20 200 5 60 57.86 57.87 25 1 60 20 200 5 60 57.88 57.87 26 1 60 20 100 8 60 52.19 57.24 27 1 60 35 200 8 60 62.49 67.69 28 1 60 35 300 5 60 70.18 71.26 29 1 100 20 200 8 60 48.51 48.46 30 1 20 20 200 5 90 99.13 105.13 31 1 20 20 200 5 30 91.97 94.60 32 1 100 20 200 2 60 41.38 39.49 33 1 60 5 200 5 30 57.27 57.80 34 1 100 20 100 5 60 44.3 40.98 35 1 60 5 200 5 90 67.33 68.19 36 1 20 5 200 5 60 86.86 92.02 37 1 60 5 200 8 60 58.05 56.55 38 1 60 20 100 2 60 45.59 50.23 39 1 60 20 200 5 60 57.85 57.87 40 1 100 35 200 5 60 64.92 55.20 41 1 60 20 100 5 90 70.63 67.78 42 1 100 20 200 5 90 52.37 61.79 43 1 60 5 100 5 60 50.94 49.80 44 1 60 20 200 5 60 57.85 57.87 45 1 100 5 200 5 60 35.59 36.16 46 1 60 20 200 8 90 82.27 75.30 removal efficiency decreases by increasing coefficients with negative values and it was found that the positive effect is for the amount of ckd and ph. the expected values of removal efficiency are listed in table 5 according to the estimated values from equation (4). table 5 analysis of variance for copper removal s o u r c e d f s e q s s c r % a d j s s a d j m s f -v a lu e p -v a lu e model 20 12134.4 95.10% 12134.4 606.72 24.29 0.000 linear 5 10486.7 82.19% 10486.7 2097.34 83.95 0.000 x1 1 8570.6 67.17% 8570.6 8570.59 343.06 0.000 x2 1 358.0 2.81% 358.0 357.97 14.33 0.001 x3 1 576.2 4.52% 576.2 576.24 23.07 0.000 x4 1 255.2 2.00% 255.2 255.20 10.21 0.004 x5 1 726.7 5.70% 726.7 726.71 29.09 0.000 square 5 1499.6 11.75% 1499.6 299.91 12.00 0.000 x12 1 703.5 5.51% 867.2 867.17 34.71 0.000 x22 1 8.6 0.07% 8.3 8.34 0.33 0.569 x32 1 7.0 0.05% 58.3 58.35 2.34 0.139 x42 1 93.1 0.73% 687.4 4.56 0.18 0.673 x52 1 687.4 5.39% 4.6 687.38 27.51 0.000 2-way interaction 10 148.2 1.16% 148.2 14.82 0.59 0.804 x1*x2 1 91.8 0.72% 91.8 91.78 3.67 0.067 x1*x3 1 0.6 0.00% 0.6 0.59 0.02 0.879 x1*x4 1 1.0 0.01% 1.0 0.97 0.04 0.845 x1*x5 1 8.7 0.07% 8.7 8.70 0.35 0.560 x2*x3 1 3.3 0.03% 3.3 3.28 0.13 0.720 x2*x4 1 2.8 0.02% 2.8 2.81 0.11 0.740 x2*x5 1 9.5 0.07% 9.5 9.52 0.38 0.543 x3*x4 1 0.9 0.01% 0.9 0.94 0.04 0.848 x3*x5 1 21.1 0.17% 21.1 21.07 0.84 0.367 x4*x5 1 8.5 0.07% 8.5 8.53 0.34 0.564 error 25 624.6 4.90% 624.6 24.98 lack-of-fit 20 624.6 4.90% 624.6 31.23 10731.3 0.000 pure error 5 0.0 0.00% 0.0 0.00 total 45 12759.0 100 % s r-sq r-sq(adj) press rsq(pred) model summary 4.998 31 95.10% 91.19% 2498.27 80. 42% anova variance analysis was used to test hypotheses about the model coefficients which could be a statistical approach splits the full variation in a very group of information into individual parts given particular sources of variation to exam hypotheses on the parameters of the model [19, 20] anova depends on the fisher f-test and p-test to work out the adequacy. the massive value of f reveals that almost all of the variation within the response is elucidated by the regression equation. the associated p-value is employed to judge whether f is large enough to point statistical significance. with a p-value of 0.00, the model designated could be elucidated 95.10% of the variability segurola et al. [21]. table 5 shows anova for the response surface quadratic model. this table presents the sum of the square (seqss), degree of freedom (df), adjusted sum of squares (adj ss), adjusted mean of square (adj ms., the value of f is equal to 24.29 at p equal to 0.00 percentage contribution (cr. %) of each parameter, f-value, and p-value. it shows great importance for the regression model. model fit quality was also validated by multiple correlations for the model. in this case, the value of the multiple correlation coefficients was 95.10% which indicates that this regression statistically significant, the model only explains 4.90% of all differences. expected value multiple correlation coefficient (former r2 = 80. 42%) which is in a reasonable agreement with the value of the adjusted multiplier correlation coefficient (r2 = 91.19%). 204 hanan a. ibraheem, husham m. al.tameemi/al-qadisiyah journalfor engineering sciences13 (2020) 200–206 anova results showed that the mineral concentration contribution percentage is 67.17%, which means that mineral concentration has the main effect on copper removal efficiency. and the rest of the variables have close proportions. the linear term contains the main percentage of the contribution to the model by 82.19%, followed by the interaction between the input variables with a contribution of 1.16% and it was small while the square contains a contribution of 11.75%. the results confirm that the heavy metal concentration (copper) is the most important factor. 3.2. effect of process variables on the copper removal efficiency fig. (2-a, 2-b) illustrates the effect of the initial concentration of copper metal on its removal efficiency for different values of contact time (30, 60 and 90 min.) and initial concentration of cu is(20,60,100 ppm) at ph 5 and the shaking rate of 200 rpm and the ckd dosage equal to 20 g / l. fig. 2a represents response surface diagram while fig. 2-b shows the corresponding contour diagram. it can be seen clearly from the surface plot that at a contact time of 30 minutes, a decrease in the removal efficiency occurs with an increase in the initial copper concentration. however, there was a slight change in the removal efficiency as the contact time approached 90 minutes. in addition, at a concentration of 100 ppm, the results show an increase in the efficiency of copper removal with increasing contact time. noting that, at a concentration of 20 ppm, a significant change in the removal efficiency occurred with increasing contact time, this was proven by the study el-awady et al. [22]. (a) (b) figure 2: response surface plot (a) and contour plot (b) showing the effect of contact time and initial concentration of copper on the copper removal efficiency fig.3 a and 3b illustrate the effect of ph on copper removal efficiency of different primary copper concentrations (20, 60, and 100 ppm) at different ph values (2, 5, and 8) at a shaking rate of 200 rpm, a 60-minute contact time and a ckd dosage of 20 g / l. the response surface plot (3a) shows that it currently has a slight impact on the copper removal efficiency as it increases slightly with increasing ph while decreasing efficiency decreases with increasing concentration. the corresponding contour piece (3-b) confirms that the maximum value of the copper removal efficiency lies in a very small area; it had a ph equal to 8 and a copper ion concentration of approximately 20 ppm. this was proven by the study coruh et al.[14], [20, 21] (a) (a)a) (b) figure 3: response surface plot (a) and contour plot (b) showing the effect of the ph and initial concentration of copper on the copper removal efficiency as for the forms (4-a, 4-b), presents the relationship of the shacking rate with the initial concentration of copper and its effect on the removal rate where the shaking rate was within (100, 200, and 300 rpm) at an initial concentration of the copper metal (20, 60 and 100) ppm. it is clear from the response surface plot (4-a) it has a significant effect on copper removal efficiency as it increases as the shaking rate increases at 300 rpm, while the removal efficiency decreased as the focus increased. the corresponding contour piece (4-b) confirms that the maximum value of the copper removal efficiency lies in a small area where the shaking rate is equal to 300 rpm and the copper ion concentration is around 20ppm. hanan a. ibraheem, husham m. al.tameemi /al-qadisiyah journalfor engineering sciences13 (2020) 200–206 205 (a) (b) figure 4: response surface plot (a) and contour plot (b) showing the effect of shaking rate and initial concentration of copper on the copper removal efficiency fig. (5-a, 5-b) shows the effect of the ckd dosage with the initial concentration of copper and its effect on the removal rate since the dosage of the to ckd was within (5, 20, and 35) g / l at an initial concentration of copper metal (20, 60 and 100) (ppm) the response surface plot (5-a) illustrates that it currently has a significant effect on copper removal efficiency as it increases with increasing dosage of ckd at 35 g / l. while the removal efficiency decreased as the focus increased. the corresponding contour piece (5-b) confirms that the maximum value of copper removal efficiency lies in a small area where the ckd dosages about 35 g / l and the copper ion concentration is about 20 ppm. (a) (b) figure 5: response surface plot (a) and contour plot (b) showing the effect of ckd dosage and initial concentration of copper on the copper removal efficiency 3.3. the optimization and confirmation test numerical optimization of the software is applied to get the precise point that maximized the desirability function (df). the desired goal was chosen by adjusting the weight or importance that could change the characteristics of the aim. five options for the aim fields for response were selected: maximum, minimum, target, within range, and none. in the present work, the aim is to get higher removal efficiency of copper so the ‘maximum’ field with corresponding ‘weight’1.0 was chosen. 35.59% was taken as the lowest limit for the removal efficiency while 100.00% was taken as the upper limit. under these settings and boundaries, the optimization procedure was conducted and the results are displayed in table 3 with the desirability function of (1). results of optimization recommended using the initial concentration of copper (20 ppm), shaking rate of (300 rpm), ph (8), contact time (90 min), and ckd dosage (35 g\l) to get higher removal efficiency of 100.6%. 206 hanan a. ibraheem, husham m. al.tameemi/al-qadisiyah journalfor engineering sciences13 (2020) 200–206 two experiments at the optimum values of the process parameters were performed to confirm the results of optimization. 20 ppm was taken as nearly the value of the initial copper concentration resulted from optimization. the results are displayed in table 4. after 90 min, 300 rpm, ph 8, and ckd dosage g\l of the experiments, the results are shown in table 7. a removal efficiency of 100% acquired, which is within the zone of the expected optimum value of removal efficiency that was acquire from optimization analysis using desirability functions table 6. table 6. optimum of process parameters for maximum removal efficiency of copper. response fit se fit 95% ci 95% pi re% 119.82 9.14 (101.00; 138.64) (98.36; 141.27) solution initial optimum parameters conc. (ppm) ckd dosage (g/l) shaking rate (rpm) ph contact time (min) re% fit composite desirability re% 20 35 300 8 90 119.819 1 table 7. confirmation of the optimum conditions for copper removal efficiency 4. conclusions it has been demonstrated that the removal of copper from a simulated solution of wastewater can be successfully performed using ckd as an absorbent material. the rms methodology is applied effectively to improve process parameters and to know the optimum levels of these parameters for copper removal resulting in increased removal efficiency. anova analysis showed a high value of r2 (0.951) as a correlation coefficient indicating good compatibility between the quadratic model and experimental results. based on rsm analysis, it can be concluded that copper concentration has the greatest influence on the efficiency of copper removal compared to other factors. the optimum values obtained from the improvement were a preliminary cu (ii) concentration of 20 ppm, ph 8, a shaking rate 300 rpm, a 90-minute contact time, and a ckd dose of 35 g / l. under these conditions, it may be possible to reduce the concentration of cu (ii) from 20 ppm to less than 0.04 ppm (re = 99.8%) at a time of 90 minutes. acknowledgments the authors appreciate the helpful and technical assistance provided by the staff and technicians in the chemical engineering department, college of engineeringuniversity of al-qadisiyah. references [1] m. el zayat, s. elagroudy, s. el haggar, equilibrium analysis for heavy metal cation removal using cement kiln dust, water science and technology, 70(6) (2014) 1011-1018. [2] m. el zayat, s. elagroudy, s. el haggar, removal of some heavy metals in selected wastewater using cement kiln dust, in: world environmental and water resources congress 2015, 2015, pp. 2459-2469. [3] who, copper in drinking‐water: background document for development of who guidelines for drinking‐water quality, in, world health organization geneva, 2004. [4] a.h. abbar, electrochemical removal of copper from a simulated wastewater using a rotating tubular packed bed of woven screens electrode, alqadisiyah journal for engineering sciences, 12(2) (2019) 127-134. [5] s.e. bailey, t.j. olin, r.m. bricka, d.d. adrian, a review of potentially low-cost sorbents for heavy metals, water research, 33(11) (1999) 24692479. [6] d. sud, g. mahajan, m. kaur, agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions–a review, bioresource technology, 99(14) (2008) 6017-6027. 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[12] a.l. mackie, m.e. walsh, bench-scale study of active mine water treatment using cement kiln dust (ckd) as a neutralization agent, water research, 46(2) (2012) 327-334. [13] m.g. klimantavièiûtë, d. virbalytë, v. pakðtas, r. juðkënas, a. pigaga, interaction of heavy metal ions with cement kiln dust, ekologija, 1 (2005) 31-36. [14] s. coruh, s. elevli, optimization study of dye removal by cement kiln dust using the central composite design of experiments, global nest journal, 17(1) (2015) 93-102. [15] a.e.-e.a.z. amin, s.a. selmy, effect of ph on removal of cu, cd, zn, and ni by cement kiln dust in aqueous solution, communications in soil science and plant analysis, 48(11) (2017) 1301-1308. [16] m.a. bezerra, r.e. santelli, e.p. oliveira, l.s. villar, l.a. escaleira, response surface methodology (rsm) as a tool for optimization in analytical chemistry, talanta, 76(5) (2008) 965-977. 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[22] m. el-awady, t. sami, removal of heavy metals by cement kiln dust, bul . environ. contam. toxicol., 59(4) (1997) 603-610. response goal lower target upper weight importance re% maximum 35.59 100 100 1 1 run initial conc. (ppm) ckd dosage (g/l) shaking rate (rpm) ph contact time (min) re% actual average run 1 20 35 300 8 90 99.78 99.79 run 2 20 35 300 8 90 99.80 99.79 article al-qadisiyah journal for engineering sciences 15 (2022) 165–172 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: eng.chem.20.post.7@qu.edu.iq (zaid m. mezher) https://doi.org/10.30772/qjes.v15i3.829 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. a catalytic cracking process on atmospheric residue from the aldiwaneyah petroleum refinery zaid m. mezher and husham m al-tameemi department of chemical engineering, college of engineering, university of al-qadisiyah, iraq 1. introduction crude oil in its natural form isn’t can usage in different specials and must be converted to the usable petroleum-based on fractions that produced by refinery in distillation unit such as kerosene, gasoline, and gas oil, also petrochemicals such as polypropylene, polyethylene, and another petroleum-based on polymers [1]–[3]. because of the rising global requested for fuel and petrochemical, upgrading the highest and heaviest boiling point section of crude oil (i.e., vacuum and atmospheric remains) is becoming more frugality appealing and possible [4]. approximately 94% of the anticipated increase in crude oil useful is due to raised consuming of light petroleum yield such as benzene, diesel, heavy and light naphtha [5]. in last years an increased request of middle and light distillates has product in the raised consumed like factory, building, and power station …i.e. for distillate of these a section to additional useful lighter yield [6]. middle and light distillates product from atmospheric crude oil residue is become very necessary for the universal refining manufacture because of the drop in traditional, light petroleum origin [7]. as a byproduct of atmospheric distillation of crude oil, which is widely used in refineries to produce light a r t i c l e i n f o article history: received 03 july 2022 received in revised form 6 august 2022 accepted 5 september 2022 keywords: r.c.r catalytic cracking batch reactor rsm a b s t r a c t the reduced crude residue r.c.r it’s a product of atmosphere distillation from crude oil in the aldiwaneyah refinery, where the product from the lower distillation tower at 300 °c thein the atmospheric distillation unit. for production of light petroleum fractions from reduced crude residue r.c.r by cracking reaction. catalytic cracking of reduced crude residue (r.c.r) was joined with a riser pressure continuous reactor was completed in an autoclave with different process selection, temperature about 350 – 450 °c, catalytic cracking time (60–120) minute, the dosage of catalyst (0.1-0.5) gm and pressure 1–5 bar in the existence of nitrogen. statistical program design of testing (rsm) by box -behnken (bb) was employed to predict the selection of necessary changes in the cracking by the catalyst of reduced crude residue (r.c.r), and to gain better process conditions. depended on the (3) plane for the design of the factorial, the cubist system was progressing between the cracking by catalyst conditions to overall production, and the more influential operator for all testing system responses was selected. the prophecy yields and conversion of all upgrade liquid phase, gas phase, coke, and residue were found to agree satisfactory with the testing grade. at a temperature of 400 °c, a pressure of 1 bar, a dosage of 0.3 gm, and a longer residence time (2 h) the best experiment is to get the maximum yield of the liquid phase product. the better run for quality when temperature 400 °c, pressure 5 bar, dosage 0.5 gm and 90 minutes as running time depended on api, sp. gr, density, viscosity, and flash point. © 2022 university of al-qadisiyah. all rights reserved. http://qu.edu.iq/ mailto:eng.chem.20.post.7@qu.edu.iq https://doi.org/10.30772/qjes.v15i3.829 http://creativecommons.org/licenses/by/4.0/ 166 zaid m. mezher and husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 crude oil upgrades, residual petroleum is left. low boiling point for fractional oil distillate such as light naphtha in an economically justifiable manner [8]. because of the decline in conventional, light petroleum supplies, the distillation of heavy petroleum remains to more profitable medium and light distillates is becoming more significant for the worldwide refining factory. catalytic cracking is one of the well-known thermochemical conversion processes that has been widely used in demand of refineries for crude oil [9]. this process has many interest, like as a stronger cracking, lower coke consistence, and is a more environmentally conscious path, when compared with cracking by thermal [10]. moreover, the cracking by catalytic of bio-oil also gives more selectivity of light olefins, such as ethylene and propylene, which represented a feed in the industry for petrochemical [11]. numerous researchers have focused on transforming low-cost feedstock to light olefins via the catalytic cracking process. the development of catalytic cracking, one of the most significant technical advances of the last three decades, has effectively revolutionized the petroleum industry (8). the most common operation for upgrading heavy oils are thermal cracking, catalytic cracking and hydrocracking. however, coke formulation through cracking is a significant challenge in these operations [12]. temperatures above (350–370) °c have identified as critical for crack (c–c), (c–h), and (c-heteroatom) bonds.[13] coke can be formed from available last molecules or produced in the feed through the reactions for the cracking by thermal. the density of these precursors (for example, asphaltene molecules) increased when their solubility selects, a modern phase known as mesophase separates from the petroleum.[14] coking, in special, is known not only for the recorded reduction in dense petroleum product but as well as a procedure for yield exceed light products. coke have about 83% carbon and 6% hydrogen and equilibrium with clearness. the basic useful of crude oil refinery it’s coke are as domestic fuel without calcining, producing of anodes, graphite, electrodes and producing of metals [15]. 2. experimental work 2.1. materials ireduced crude residue (r.c.r) the reduced crude residue (rcr) product is one of the products of the atmospheric distillation tower in the crude oil refining process, as it has a higher molecular weight and a high boiling point and is characterized by containing light and medium petroleum derivatives, so the cracking process in general is capable of converting the heavy hydrocarbon compounds present in rcr into petroleum derivatives. iicharacterization r.c.r reduced crude residue r.c.r thermal cracking experiments were conducted on atmospheric residue (r.c.r) from al-diwaniya refinery in iraq with physical properties are given in tables 1 and nitrogen as inert gas used to cooling reactor and to leak check before any run. iiizeolite hy in order ot specify the nature and properties of the prepared zeolite in any method, many tests to be apply. the particle size, molecular structure, chemical composition and activity are possible to be known. table 1. physical properties of reduced crude residue r.c.c in petroleum al-diwaneyah refinery figure 1. the typical framework structure of zeolite y table 2. specification of zeolite hy product name zeolite type hy application catalyst appearance powder. white. odor odorless melting point 1000 sio2/al2o3 mole ratio 5.1 na2o % 2.8 unit cell size (a) 24.5 surface area (m2/g) 700 country of origin the netherlands specification value specific gravity at 60/60 °f 0.9725 api 14.0 flash point 90 °c density 0.9718 gm/cm3 viscosity @ 50 °c 250.1 cst sulfur wt. % 4.62 pour point °c -7 zaid m. mezher, husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 167 sem analysis of zeolite figure 4 shows sem study the morphology shape and size of the synthesized crystals. the sem images of the samples show that the morphology of all the samples as expected for zeolite hy. transmission infrared spectroscopy (ft-ir) infrared spectroscopy is commonly used to study the silica aluminate framework, hydroxyl group and also adsorbed molecules in zeolite. x-ray diffraction patterns (xrd) x-ray used to explain the crystallinity, electronic microscopes image is clearing the particles size and shapes, and chemical analysis helps to understand the composition of particles. x-ray powder diffraction technique is the best method to define the crystallographic structure of zeolite. each zeolite has their own specific pattern that can be used as references for the determination of solid crystal phase and it is used as fingerprint for every zeolite. this technique can signify whether the solid sample is amorphous or crystalline phase, the degree of crystallinity and identification of phase present. figure 2. xrd for zeolite hy 2.2 catalytic properties of the zeolites in 1962 the zeolites were introduced by mobil oil corporation as new cracking catalysts in refinery technology. they were characterized by top activity and selectivity in breaking and breaking with hydrogen. at the end of the 1960s, the concept of shape-selective catalysis with zeolites was introduced to petrochemistry (electroforming process), and the zeolites became of higher importantly in catalysis research and applied catalysis. zeolites advantages over conventional catalysts can be summarized as follows: 1 crystalline and therefore precisely defined arrangement of sio4 and alo4 tetrahedra. this results in good reproducibility in production. 2shape selectivity: only molecules that are smaller than the pore diameter of the zeolite undergo reaction. 3controlled incorporation of acid centers in the intracrystalline surface is possible during synthesis and/or by subsequent ion exchange. 4-up 300o c zeolite y have acidities comparable to those of mineral acids. 5catalytically active metal ions can be uniformly applied to the catalyst by ion exchange or impregnation. subsequent reduction to the metal is also possible. 6zeolite catalysts are thermally stable up to 600oc and can be regenerated by combustion of carbon deposits. 3. experimental setup as shown in fig. 3, the equipment consists the following items: i. reactor made from 316 stainless steel at size approximately (1 liter). ii. nitrogen bottle. iii. vent valve. iv. thermocouple. v. condenser. vi. temperature indicter. vii. power switch. viii. magnetic pump. ix. product container storage (250 mm). x. sensitive balance. xi. dryer 3.1 catalytic cracking test: the test worked for catalytic cracking of reduced crude residue consisted of a rise-pressure and temperature uncontained reactor. the schematic diagram of the test setup is explained in fig. 1. the autoclave was used to conduct catalytic cracking tests. to ensure sample homogeneity, the autoclave was placed in a preheated vertically electric furnace with a magnetic stirrer. wash the reactor with distilled water and then dry it in the dryer for a quarter hour. after placing and securing the reactor in the main 168 zaid m. mezher and husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 apparatus, a pressure leak check was completed by using nitrogen gas and charging the pressure to the reactor at 150 psi for 5 minutes. following the leak test, the pressure in the reactor was vented, and the reactor was again charging with nitrogen for 5 minutes to remove any remaining air via continuously sending out nitrogen from the reactor.[13] nitrogen gas was given to the system at a constant pressure via pressure regulators from nitrogen cylinders. the reactor in the unit was filled with 300 g of (r.c.r) with the dosage of catalyst its (0.1, 0.3, 0.5) gm, after that increasing the temperature by using electrical heater. the external valve for the reactor was closed before increasing the temperature for reduced crude residue (r.c.r) was heated in an oven for each test. the sample of r.c.r sample and zeolitehy was filled into a reactor at size (1000 ml) made from 316 stainless steel in electrical heating furnace with cover to maintain temperature were connected to power supply consumed about 1500 kw. the temperature of the autoclave was recorded/selected using by system control, manual controller and nitrogen. the pressure of the autoclave was recorded/selected by product valve, rpm for magnetic stirrer and if the pressure high over the set point will check valve working. the pipe line for production with (10 mm. i.d) also manufacture from 316 stainless steel. figure 3. schematic representation of the experimental procedures unit with controls system the reactor was heated to the desired temperature at a rate of 25 c/ min. when the reactor temperature reached 120 ◦c, an electromagnetic stirrer began mixing the contents at 500 rpm [13]. the stirrer speed can be selected by a dc change speed selector. bath water keep on the magnetic stirrer at safe temperature level during experimental test to maintain magnetic in stirrer. unit temperature in reactor of 300 ◦c recorded the starting point of the reaction, and the residence time was calculated at 300 ◦c. [13] the product from the yield valve was undergo to the bath water to condensing the gas product and cooling the liquid product. after completion, the heating jacket was turned off and removed. the reactor was then leave for 5 hours to cool to room temperature for tests without quenching.[13] once at room temperature, the uncondensed gases, primarily c1 to c3 .each test's liquid yield was calculated inter alia the mass of the liquid phase product and the mass of the feed. the liquid production was thoroughly mixed, and the api gravity was determined at ambient temperature by a 250 ml pycnometer. the viscosity measured at 50 ◦c for heavy liquid or 40 ◦c for light liquid by a brookfield digital viscometer equipped with a temperature-controlled water bath for the liquid phase product.[13] the supernatant was putted in special package, and its mass him were measured. the density and specific gravity of the liquid product were also measured beside api, flash point. the experiment is then repeated several times based on the difference in pressure, temperature, and contact time. each gas product for any test was collected in a gas pack and analyzed using a gas chromatography (gc). weighted the remaining coke and liquid product, as well as wash the reactor. the conversion for all the test were obtained by using the following equations: % conversion = massfeed−massresidue massfeed ∗ 100% (1) yield is defined as a mass of the cracking in the liquid phase product divided by the mass of crude oil atmosphere residue (r.c.r) feed: massgas product = massfeed − (massliquid product + masscoke + massresidue ) (2) liquidyield = mass of liquid product massfeed ∗ 100% (3) gasyield = mass of gas product mass of feed ∗ 100% (4) cokeyield = mass of coke product massfeed ∗ 100% (5) residueyield = mass of residue product massfeed ∗ 100% (6) 3.2 experimental design the response surface methodology (rsm) was used to assess the effects of process selection on r.c.r thermal cracking and obtain total conversion and physical property values for the product. rsm is a set of statistical and mathematical techniques for modeling and analyzing problems in which a response of interest is influenced by many variables and the aim is to optimum analysis this response. the procedure was investigated using box-behnken. the response surface model, which is based on box-behnken, is the most widely used design method for three variable or more formation in environmental processes. furthermore, box-behnken provides excellent prediction of linear and square interaction effects of variables affecting the chosen mechanism. box-behnken requires three level of points: center points, axial points, and cube points derived from factorial nature. the independent variable were the pressure (a), temperature (b) and reaction time (c). the factors named and levels are shown in table 2. table 3. the three factors: pressure, temperature, time and their level factor code unit low level (-1) medium level (0) high level (+1) pressure a °c 1 3 5 zaid m. mezher, husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 169 temperature b min 350 400 450 time c bar 60 90 120 dosage d gm 0.1 0.3 0.5 4. results and discussion we measured the density from specific gravity (astm) table by api standard number. the °api gravity at 60 °f was measured with a 250 ml specific gravity flask. 4.1 specific gravity a specific gravity scale measured by the american petroleum institute (api) for selection the number density of various petroleum liquids phase production. i.e. api = (141.5/sp.gr) -131.5. 4.2 effect of temperature on the experimental fig. 4 and table 4 shows the relation between the liquid yield and the variable condition for every run. from this figure the difference in yield between runs increased with increased temperature for the same time, dosage and pressure with constant rotary per minute for magnetic stirrer. fig. 5 and table 4 shows the relation between the gas yield and the variable condition for every run. from this figure the difference in yield between runs increased with increased temperature for the same time, dosage and pressure with constant rotary per minute for magnetic stirrer. fig. 6 and table 4 shows the relation between the coke yield and the variable condition for every run. from this figure the difference in yield between runs increased with increased temperature for the same time, dosage and pressure with constant rotary per minute for magnetic stirrer. figure 4. the 2d mean of liquid yield with run condition (temperature, time, dosage, and pressure) 170 zaid m. mezher and husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 figure 5. the 2d mean of gas yield with run condition (temperature, time, dosage, and pressure) fig. 7 and table 4 shows the relation between the residue and the variable condition for every run. from this figure the difference in residue between runs decreased with increased temperature for the same time, dosage and pressure with constant rotary per minute for magnetic stirrer. from table 5 show the relation between the run and physical properties there for we note increased quality with increased temperature with the same condition for pressure, dosage and time depended on api, d ensity and sp.gr. 4.3 effect of pressure on the experimental fig. 4 and table 4 shows the relation between the liquid yield and the variable condition for every run. from this figure the difference in yield between runs the yield decreased with increased pressure for the same time, dosage and temperature with constant rotary per minute for magnetic stirrer. fig. 5 and table 4 shows the relation between the gas yield and the variable condition for every run. from this figure the difference in yield between runs the yield decreased with increased pressure for the same time, dosage and temperature with constant rotary per minute for magnetic table 4. the experimental results obtained by catalytic cracking based on box-behnken run pressure, bar temp, c time, min dosage, %wt liquid yield %wt gas yield %wt coke %wt residue %wt 1 3 450 120 0.3 68.51 07.32 15.81 08.36 2 3 400 120 0.5 78.81 13.07 04.33 03.79 3 1 400 120 0.3 81.37 06.90 10.43 01.30 4 5 400 060 0.3 63.46 06.02 02.11 28.41 5 3 400 090 0.3 65.92 07.83 07.78 18.47 6 3 350 090 0.1 65.70 04.54 03.92 25.84 7 3 450 090 0.5 77.68 12.75 05.11 04.46 8 3 350 120 0.3 57.78 06.56 24.36 11.30 9 1 400 090 0.5 81.31 08.22 06.67 03.80 10 3 400 060 0.5 80.15 10.12 05.48 04.25 11 5 400 090 0.1 65.50 05.26 02.08 27.16 12 1 350 090 0.3 70.46 06.23 13.49 09.82 13 3 350 060 0.3 63.06 04.57 11.20 21.17 14 1 400 060 0.3 69.22 03.91 21.64 05.23 15 3 450 090 0.1 71.52 05.89 15.13 07.46 16 3 400 090 0.3 65.92 07.83 07.78 18.47 17 1 400 090 0.1 70.97 06.98 09.22 12.83 18 3 350 090 0.5 78.33 10.26 04.76 06.65 19 3 400 090 0.3 65.92 07.83 07.78 18.47 20 1 450 090 0.3 76.63 07.30 12.85 03.22 21 5 350 090 0.3 61.26 04.93 04.43 29.38 22 3 400 060 0.1 57.69 06.24 14.34 21.73 23 3 400 120 0.1 58.39 06.68 18.21 16.72 24 5 450 090 0.3 67.09 07.88 11.25 13.78 25 5 400 090 0.5 72.44 14.52 02.62 10.42 26 3 450 060 0.3 68.97 10.19 05.62 15.22 27 5 400 120 0.3 65.81 7.920 08.36 17.91 table 5. physical properties for liquid product run pressure, bar temp, c time, min dosage, %wt density sp.gr api 1 3 450 120 0.3 0.7888 0.7892 47.8 2 3 400 120 0.5 0.7258 0.7260 63.4 3 1 400 120 0.3 0.8310 0.8314 38.7 4 5 400 060 0.3 0.7823 0.7826 49.3 5 3 400 090 0.3 0.8124 0.8128 42.6 6 3 350 090 0.1 0.8708 0.8713 30.9 7 3 450 090 0.5 0.7225 0.7227 64.3 8 3 350 120 0.3 0.8185 0.8189 41.3 9 1 400 090 0.5 0.7729 0.7732 51.5 10 3 400 060 0.5 0.7322 0.7324 61.7 11 5 400 090 0.1 0.8489 0.8493 35.1 12 1 350 090 0.3 0.8530 0.8534 34.3 13 3 350 060 0.3 0.8319 0.8324 38.5 14 1 400 060 0.3 0.8494 0.8504 34.9 15 3 450 090 0.1 0.8525 0.8529 34.4 16 3 400 090 0.3 0.8124 0.8128 42.6 17 1 400 090 0.1 0.8855 0.8860 28.2 18 3 350 090 0.5 0.7402 0.7405 59.6 19 3 400 090 0.3 0.8124 0.8128 42.6 20 1 450 090 0.3 0.8433 0.8438 36.2 21 5 350 090 0.3 0.7928 0.7932 46.9 22 3 400 060 0.1 0.8660 0.8665 31.8 23 3 400 120 0.1 0.8582 0.8586 33.3 24 5 450 090 0.3 0.7679 0.7682 52.7 25 5 400 090 0.5 0.7155 0.7157 66.2 26 3 450 060 0.3 0.8064 0.8067 43.9 27 5 400 120 0.3 0.7613 0.7616 54.3 zaid m. mezher, husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 171 stirrer. fig. 6 and table 4 shows the relation between the coke yield and the variable condition for every run. from this figure the difference in yield between runs increased with increased pressure for the same time, dosage and temperature with constant rotary per minute for magnetic stirrer. fig. 7 and table 4 shows the relation between the residue and the variable condition for every run. from this figure the difference in residue between runs the residue increased with increased pressure for the same time, dosage and temperature with constant rotary per minute for magnetic stirrer. from table 5 show the relation between the run and physical properties there for we note increased quality with increased pressure with the same condition for temperature, dosage and time depended on api, density and sp.gr . 4.4 effect of time on experimental fig. 4 and table 4 shows the relation between the liquid yield and the variable condition for every run. from this figure the difference in yield between runs the yield increased with increased time for the same pressure, dosage and temperature with constant rotary per minute for magnetic. fig. 5 and table 4 shows the relation between the gas yield and the variable condition for every run. from this figure the difference in yield between runs the yield decreased with increased time for the same pressure, dosage and temperature with constant rotary per minute for magnetic stirrer. figure 6. the 2d mean of coke yield with run condition (temperature, time, dosage and pressure) figure 7. the 2d mean of residue with run condition (temperature, time and pressure) fig. 6 and table 4 shows the relation between the coke yield and the variable condition for every run. from this figure the difference in yield between 172 zaid m. mezher and husham m al.tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 165–172 runs increased with increased time for the same pressure, dosage and temperature with constant rotary per minute for magnetic stirrer. fig. 7 and table 4 shows the relation between the residue and the variable condition for every run. from this figure the difference in residue between runs the residue decreased with increased time for the same pressure, dosage and temperature with constant rotary per minute for magnetic stirrer. from table 5 show the relation between the run and physical properties there for we note increased quality with increased time with the same condition for pressure and temperature depended on api, density and sp.gr. 4.5 effect of dosage on experimental fig. 4 and table 4 shows the relation between the liquid yield and the variable condition for every run. from this figure the difference in yield between runs the yield increased with increased dosage for the same time, pressure and temperature with constant rotary per minute for magnetic. fig. 5 and table 4 shows the relation between the gas yield and the variable condition for every run. from this figure the difference in yield between runs the yield decreased with increased dosage for the same time, pressure and temperature with constant rotary per minute for magnetic stirrer. fig. 6 and table 4 shows the relation between the coke yield and the variable condition for every run. from this figure the difference in yield between runs increased with increased dosage for the same time, pressure and temperature with constant rotary per minute for magnetic stirrer. fig. 7 and table 4 shows the relation between the residue and the variable condition for every run. from this figure the difference in residue between runs the residue decreased with increased dosage for the same time, pressure and temperature with constant rotary per minute for magnetic stirrer. from table 5 show the relation between the run and physical properties there for we note increased quality with increased dosage with the same condition for pressure, time and temperature depended on api, density and sp.gr. 5. conclusions catalytic cracking of the reduced crude residue r.c.r was carried out in a batch reactor.in an autoclave with different process selection, temperature about 350–450 °c, catalytic cracking time 60 -120-minute, dosage of catalyst (0.1-0.5) gm and pressure 15 bar in the existence of nitrogen. x-ray used to calculate the relative crystallinity of catalysts zeolite hy, the experimental design was utilized to optimize liquid yield, gas yield, coke and residue by using the four parameters pressure, temperature, time and dosage of catalyst. a low conversion occurs in the liquid yield, gas yield and coke yield and increasing in the heavy residue amount of the cracking process when decreased the time and temperature of the process with constant pressure therefore to prevent the thermal cracking from fouling it necessary to maintain the system at high temperature and residence time as possible the highest liquid yield was 71.05 at pressure 1 bar and temperature 400c and 120 minutes, and the lowest liquid yield was 44.58 at 5 bar and 350 c and 90 min, therefore the optimum conditions is that keep high liquid yields which mean run number 10. an increasing the pressure decreases (with keeping the values of the other variables (temperature and time)), it noticed all the responses of the process will increased that liquid yield will increase from 48.14 to 53.32 and the gas yield also increased from 4.32 to 5.58, also the coke yield was increased from 12.0 to 18.1. run 8 and run 9 show optimum conditions of the cracking process because it gives 0 residue and the highest value of the liquid, gas and coke yields ranging from 54.87 to 69.21 and 5.60 to 6.0 and 18.2 to 24.79 respectively. the optimum run represents by run number 2 where the of operation conditions were 3 bar pressure, 400 co temp, 120-minute time and 0.5 %wt as catalysts dosage, where the liquid and the gas yield was 78.81 and 13.07 respectively as weight percentage, also the coke and residue percentages were 4.33 %wt and 3.79 %wt respectively. references [1] m. d. garba and a. galadima, “catalytic hydrogenation of hydrocarbons for gasoline production,” j. phys. sci., vol. 29, no. 2, pp. 153 –176, 2018, doi: 10.21315/jps2018.29.2.10. 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[15] s. m. alrubaye, m. s. hameed, and a. d. affat, “studying thermal cracking behavior of vacuum residue,” iraqi j. chem. pet. eng., vol. 21, no. 3, pp. 45– 49, 2020, doi: 10.31699/ijcpe.2020.3.6. article al-qadisiyah journal for engineering sciences 14 (2022) 184–190 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ajah580@gmail.com (nikolai nikolaevich) https://doi.org/10.30772/qjes.v14i3.851 2411-7773/© 2022 university of al-qadisiyah. all rights reserved . this work is licensed under a creative commons attribution 4.0 international license. simulation of temperature distribution in gas turbine stator blade subjected to different internal coolant gases naseer h. hamza 1, dhafer a. hamzah 1 , khaled a. al-farhany 1, mohamed f. al-dawody 1, efimov nikolai nikolaevich 2* 1 department of mechanical engineering, college of engineering, university of al-qadisiyah, al-qadisiyah, 58001, iraq 2 department of thermal power plants and heat engineering, platov south-russian state polytechnic university (npi), 346428, novocherkassk, the russian federation a r t i c l e i n f o article history: received 05 december 2021 received in revised form 02 february 2022 accepted 01 march 2022 keywords: simulation, internal cooling coolant gases von mises stress gas turbine blade a b s t r a c t the gas turbine blade stator is subjected to a severe high temperature of hot incoming gases from the combustor. in order to avoid the melting of the stator, film and internal cooling techniques are applied by using a bypass stream of air from the compressor as a coolant fluid. these techniques have their own merits, but it is limited by some constraints like the value of specific heat of air. in this paper different gases with higher specific heat are used as a coolant in order to increase the thermal capacity of coolant fluid which in turn increases the amount of transferred heat. the selected gases are helium, steam, and ammonia are applied in comsol multiphysics® in order to simulate the cooling process and the temperature distribution. at first, the air is applied and the results show a good agreement with previous literature and then the other coolants to compare their results with the air. the results show that the helium affects the cooling process strongly and it cools the blade to safer limits rather than air by about 50%, but it increases von mises stress by about 71% in comparison with air. the two other coolants also have a good and effective cooling performance, but they almost show an identical performance. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction regarding its merits, gas turbine engines become the most reliable and promising units in many industrial and aviation fields to generate power and thrust force and to compensate loads at peak load situations. thermal and power output of these engines is still limited by the metallurgical limit of turbine blades. any higher turbine inlet temperature beyond the fusion point of the blade alloy leads certainly to thermal failure of the unit especially in the presence of high rotational effect on the rotor. to avoid such a situation in the operation, a cooling technique is adopted by manufactures internally to reduce the severe temperatures and to increase the operational hours of the unit as long as it operates at safe limits [1-3]. different cooling methods are proposed like film and internal cooling or both of them depending on the conditions of the application area of gas turbine engine itself. among them, internal cooling, mostly incorporated via cooling passages inside the blade. internal cooling configurations also http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ naseer hamza et al. /al-qadisiyah journal for engineering sciences 14 (2022) 184–190 185 imply different geometries and shapes to get better performance and effect [4-7] . al ali and janajreh [8] performed a theoretical analysis of different configurations on the heat transfer via impingement cooling. moskalenko and kozhevnikov [9] estimated the gas turbine blade cooling efficiency by simulating two medium of cooling, i.e., water vapor and air. in their results, they found that water vapor is more efficient than air for the same working pressure and temperature by about 30%. deepanraj et al. [10] studied by using different models with different holes by using a finite element method to find out the optimum number of holes for good performance. they found that when the numbers of holes are increased in the blade, the temperature distribution is decreased dramatically. the ribs in the cooling channels play an important role since they increase the turbulence level, which in turn enhances the heat transferred between the inner wall and coolant. xie et al. [11] studied their effect on different paths at different reynold numbers. they found an improvement in heat transfer, but the pressure drop should be accounted. since the blade is mounted on the rotating disc which rotates, usually at very high rotational speed, the effect of rotation is also has been investigated. burberi et al. [12] studied the effect of rotation on the heat transfer coefficient especially at the leading edge zone. their findings indicate an effect at the tip region but it vanishes at the hub region. optimization of internal cooling is also investigated by researchers in order to find the optimum parameters of the whole process [13-15]. mousavi et al. were also interested in finding optimum cooling. in their works [16, 17] they performed a numerical analysis in three-dimensional model to optimize the hole of cooling serpentines and their distribution along the chord of the gas turbine blade. their results show a huge reductio n in mass flow rate of the cooling air extracted from the compressor which in turn positively affects the output power and thermal efficiency of the gas turbine engine. weak attention was directed in previous studies to the type of coolant and its physical properties. finding an effective coolant has become a challenge as it is influenced by a large number of flow and geometrical parameters. this paper is dedicated to analyzing the gas turbine blade when subjected to different coolant in three case studies to find its effect on the internal cooling and severe temperature distribution. 2. mathematical model the governing equation of the flow field of the flowing air can be expressed as follows: • turbulence model where 𝑢𝑖 ′ 𝑢𝑗 ′̅̅ ̅̅̅̅ should be calculated by using a suitable turbulence model. because of complex flow phenomena inside the cooling channels of the blade, the type of turbulence model should provide acceptable accuracy in the calculation of heat transfer cooling. many models had been selected in previous studies to simulate the turbulent heat transfer, among them, the shear stress transport (sst) turbulence model [5] and the renormalized group (rng) k-ε model [18, 19] which show a good convergence in their result. a low-reynolds number (lrn) k-ω turbulence model, with improved heat transfer predictions, is proposed by bredberg j. in his works [20-26] which shows better results and convergence, especially as it takes into account the rotational effect of the gas turbine and th us it has been selected in this paper. • heat transfer in a solid zone the dominant mechanism of heat transfer in the turbine of the gas turbine engine is the convection heat transfer. since there’s flowing hot gas outside the blades and relatively cold co olant inside the blade flowing through the cooling duct, this model of convective heat transfer seems to be reasonable which is usually defined by: 𝑄𝑐𝑜𝑛𝑣 = 𝛼𝐴(𝑇𝑤 − 𝑇𝑎 ) (3) the heat transfer coefficient (α) needs to be calculated accurately and accounted on well-known dimensionless parameter nusselt number and the latter itself in the forced convection is a function of reynold and prandtl numbers, so 𝑁𝑢 = 𝛼𝐿𝑐 𝜆 (4) the characteristic length lc varies for different zones in the gas turbine blade. to obtain precise calculations of the magnitude of heat transfer quantity, the heat transfer coefficient will be calculated in different forms according to zones where a heat transfer occurs. heat transfer in the cooling ducts of the blade 𝛼 = 𝑁𝑢𝜇𝑐𝑜𝑜𝑙𝑎 𝑛𝑡 𝐶𝑝𝑐𝑜𝑜𝑙𝑎𝑛𝑡 (𝑃𝑟𝑐𝑜𝑜𝑙𝑎𝑛𝑡 𝐿𝑐) (5) nomenclature: greek symbols q heat transferred (w) α heat transfer coefficient (w/m2 k) k turbulent kinetic energy ɛ rate of energy dissipation nu nusselt number δp pressure drop (pa) p pressure (pa) µ fluid dynamic viscosity (pa s) c_p the heat capacity (j/kgk) ρ density (kg/m3) pr prandtl number λ thermal conductivity (w/mk) qw wall heat flux (w/m2) κ the turbulence kinetic energy a area (m2) subscripts re reynold number a air, ambient t temperature (k) c characteristics length ui the velocity in the x_i direction, (m/s) coolant coolant gas used in cooling 186 naseer hamza et al. /al-qadisiyah journal for engineering sciences 14 (2022) 184–190 heat transfer at the pressure and suction sides of the blade the heat transfer here is assumed to be external forced convection on a flat plate with local heat transfer coefficient 𝛼 = { 𝑘 𝑥 0.332𝑃𝑟 1 3𝑅𝑒 𝑥 1 2 𝑖𝑓 𝑅𝑒𝑥 ≤ 5 × 10 5 𝑘 𝑥 0.0296𝑃𝑟 1 3𝑅𝑒 𝑥 4 5 𝑖𝑓𝑅𝑒𝑥 > 5 × 10 5 (6) heat transfer at the top and bottom sides of the blade the same equation above is adopted with a difference in the characteristic length. 3. numerical simulation the numerical simulation is performed using software package comsol multiphysics® in order to model the different cases adopted in this study. in order to isolate the effect of the type of coolant, the operating conditions and other parameters are kept with no change. to obtain good results, a fine mesh was generated near the channel walls and the fluid flow domain so as to capture the temperature variations because of coolant fluid flow throughout the channels. the blade material was chosen to be a nickel super-alloy inconel 718, which is being used widely in aerospace related applications. the physical properties of the coolant are chosen to be a function of temperature as illustrated in table 2. the values of the constants are taken from the study of [27]. the case geometry is shown in fig. 1 with the mounting details of the blade. fig. 2 shows the cooling ducts and the passages where coolant fluid flows inside the gas turbine blade to reduce the severe temperature and hot spot which usually occur on the blade surface because of the hot incoming burned gases from the combustion chamber of a gas turbine engine. the duct geometry does not include any ribs or turbulators. table 2. physical properties of the air coolant as a function of temperature [26] property function unit density 352.7𝑇−1 [kg/m3] specific heat capacity 1093 − 0.6356 𝑇 + 1.634 × 10−3𝑇2 − 1.413 × 10−6 𝑇3 + 5.595 × 10−10 𝑇4 − 8.663 × 10−14𝑇5 [j/(kg.k)] dynamic viscosity 3.893 × 10−6 + 5.754 × 10−8 𝑇 − 2.676 × 10−11 𝑇2 + 9.710 × 10−15𝑇3 − 1.356 × 10−18𝑇4 [kg/(m.s)] figure 1. the geometry of the gas turbine stator blade (a) 3d model (b) top view figure 2. the passages of cooling ducts inside the gas turbine stator 4. mesh generation in the first step, the blade geometry was built in the solidworks software. two camber lines were used to create the side boundaries. then, this geometry was exported fro m solidworks and later imported into comsol multiphysics software to build up the mesh because of its flexibility for creating a mesh. for faster calculations and performance, as we go farther from the blade into the fluid domain, the mesh size becomes larger and larger as shown in fig. 3. complete mesh consists of 623212 domain elements, 137704 boundary elements, and 15913 edge elements. minimum quality: 0.1604; average quality: 0.6555. the operating and boundary conditions are listed in table 1. figure 3. the mesh of the gas turbine blade naseer hamza et al. /al-qadisiyah journal for engineering sciences 14 (2022) 184–190 187 table 1. the operating and boundary conditions of the case study description value parameter gas velocity on stator suction side 150 m/s u_suction_side gas velocity on stator pressure side 100 m/s u_pressure_side gas velocity along platform walls 100 m/s u_platform working gas temperature 1200 k t_gas high pressure level 14 bar p_high cooling air temperature 600 k t_cool characteristic length scale of cooling channels 0.01 m h_cool working temperature 900 k t_work 5. results verification the results of the current model of first common coolant (air) show a good and reliable agreement with the results of many authors who applied their numerical simulation and compared them with experim ental data of many researchers, foremost among them hylton et al. [28]. among these cases study, the case study of [29] had been re-modeled and simulated in the current software program at the same geometry, boundary conditions and other numerical values, the results were approximately the same in terms of temperature distribution and heat transfer as shown in fig. 4. based on this agreement, the other cases are judged to be accepted. a. the results of current model b. the results of [29] figure 4. the results verification with other research paper 6. results and discussion the main focus in the results section of the simulation process is dedicated to thermal stresses and the temperature distribution across the blade crosssection. because of the great significance of these two parameters which indicate the metallurgical failure limit when the hot incoming gases from the combustion chamber exceed – generally or locallythe melting point of the alloy. beginning with the base case when the coolant is air, which represents the embark line to compare the three other cases with it. the von mises stress is shown in fig. 5 which clearly indicates that maximum stress is occurring inside the cooling duct. this is because of the large temperature difference between the temperature of the inner side of the stator and the temperature of flowing coolant fluid causing thermal stress to be increased. on the other hand, the maximum stress in the case of other coolant is much larger than that of air, especially in the case of using helium as a coolant as shown in figs 6-8. the maximum percentage increase compared to air is 71% and the minimum is 45% as indicated in table 3. figure 5. the von mises stress in case of air coolant figure 6. the von mises stress in case of helium coolant figure 7. the von mises stress in case of ammonia coolant 188 naseer hamza et al. /al-qadisiyah journal for engineering sciences 14 (2022) 184–190 figure 8. the von mises stress in case of steam coolant table 3. the maximum and minimum values of von mises stress at different scenarios of cooling type of coolant max stress occurred (10 8 pa) min stress occurred (10 5 pa) percentage increase of max stress air 7.67 4.09 -- helium 13.1 4.38 70.80% ammonia 11.1 4.32 44.72% steam 11.2 4.29 46.02% the most important parameter in the gas turbine engine is the turbine inlet temperature since it determines the magnitude of the power output. designers often avoid hitting the maximum temperature of the alloy that the blade is made from. because the temperature distribution is nonuniform, a hot spot may appear on the surface of the blade and causes thermal failure. according to the aforementioned, the temperature distribution and its contour have a great significance in this study to determine the maximum and minimum temperature occurred and its location to avoid the high and severe hot spot. fig. 9 shows the temperature distribution in case of using air as a coolant which is the reference case in this study. the value of maximum temperature is approximately the same temperature as the hot incoming gases surrounding the stator blade. the minimum temperature is higher than the coolant temperature entering the cooling channels from the bottom of the blade and it is 663 k in case of using air as coolant gas to minimize the hot spot temperature differences on the blade surface. the performance of the other coolant gases is much better than air where the minimum temperature recorded is 602 k, 609 k and 610 k in the case of helium, ammonia, and steam consequently as shown in figs 10-12. the minimum temperature difference of the multiple coolant gases compared to the minimum temperature difference in case of air is shown in table 4. figure 9. the temperature distribution in case of air coolant figure 10. the temperature distribution in case of helium coolant figure 11. the temperature distribution in case of ammonia coolant naseer hamza et al. /al-qadisiyah journal for engineering sciences 14 (2022) 184–190 189 figure 12. the temperature distribution in case of steam coolant table 4. the minimum values of temperature difference at the stator surface at different scenarios of cooling. type of coolant temperature of hot incoming gases (k) min temperature recorded in the stator (k) difference in temperature (k) percentage reduction of max temperature air 1200 663 537 44.8% helium 1200 602 598 49.8% ammonia 1200 609 591 49.3% steam 1200 610 590 49.2% the cooling effect as the convection process continues from the entering to exiting sections of the coolant gases is decreasing as the heat transfers from the hot wall to the cold fluid. also, this reduction in cooling effect can be seen across the top view of the stator blade where the maximum temperature and hot spots tend to appear at the trailing edge of the stator while the leading edge has a moderate average temperature in general as shown in fig. 13. this indicates that the mass flow rate of coolant gas is inadequate to cover all zones in the stator blade and to eliminate the hot spot at the trailing edge; the mass flow rate should be increased to overcome the high temperatures. any increase in mass flow rate or the bleeding from the compressor may lead to a decrease in the efficiency of the gas turbine engine in terms of overall performance parameters, so a good and reasonable compromise should be taken into account. the behavior of three coolant gases is different from that of air as shown in fig. 14 which shows the temperature distribution along the blade in xcoordinate only from the trailing edge to leading edge. these values do not represent the most minimal values since the latter occurs at different spatial coordinates. (a) air (b) helium (c) ammonia (d) steam figure 13. the temperature distribution in a slice section for different coolant gases. 190 naseer hamza et al. /al-qadisiyah journal for engineering sciences 14 (2022) 184–190 figure 14. the temperature distribution from trailing edge to leading edge in case of different coolant gases 7. conclusions gas turbine stator blade is subjected to severe high temperature and in order to operate it at the safe limit, a cooling process is proposed to eliminate the hot spots appear at the stator surface. in the common operation of the gas turbine engine, bleeding of air is drawn to cool the blade. the air shows a good and reliable performance in cooling the blade, but it still inadequate. according to the results of the current study, it can be concluded that: 1. the three different gases show a better scenario of cooling than air, but they increase the von mises stress in the blade because of a relatively large temperature difference. 2. the ammonia and steam show the same performance approximately so the choice of one of them may be determined by economic justification. 3. in all cases mentioned earlier, the trailing edge zone of the stator still suffers from the high severe temperature the situation that indicates insufficient coolant gas mass flow rate. 4. a good compromise is needed to optimize these different factors to get an effective cooling process at justified economic level especially that using a different coolant rather than air, an extra kit of equipment will be incorporated. references [1] salazar, s., conjugate heat transfer on a gas turbine blade. 2010. 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[12] burberi, e., et al., effect of rotation on a gas turbine blade internal cooling system: numerical investigation. journal of turbomachinery, 2017. 139(3): p. 031005. [13] morrone, b., et al. optimization of a gas turbine stator nozzle cooling using genetic algorithms. in int. symp. on heat transfer in gas turbine systems, antalya, turkey, august. 2009. [14] nowak, g. and i. nowak, shape design of internal cooling passages within a turbine blade. engineering optimization, 2012. 44(4): p. 449-466. [15] kim, k.m., et al., optimal design of impinging jets in an impingement/effusion cooling system. energy, 2014. 66: p. 839 -848. [16] mousavi, s.m., a. nejat, and f. kowsary, optimization of turbine blade cooling with the aim of overall turbine performance enhancement. energy equipment and systems, 2017. 5(1): p. 71 -83. [17] mousavi, s.m. and s.m. rahnama, shape optimization of impingement and film cooling holes on a flat plate using a feedforward ann and ga. energy equipment and systems, 2018. 6(3): p. 247 -259. [18] al-shamani, a.n., et al., enhancement heat transfer characteristics in the channel with trapezoidal rib –groove using nanofluids. case studies in thermal engineering, 2015. 5: p. 48 -58. [19] immarigeon, a. and i. hassan, an advanced impingement/film cooling scheme for gas turbines–numerical study. international journal of numerical methods for heat & fluid flow, 2006. 16(4): p. 470-493. [20] bredberg, j., prediction of flow and heat transfer inside turbine blades using earsm,-and-turbulence models. 1999. [21] bredberg, j., on the wall boundary condition for turbulence models. chalmers university of technology, department of thermo and flui d dynamics. internal report 00/4. g oteborg, 2000. [22] bredberg, j., on two-equation eddy-viscosity models. department of thermo and fluid dynamics, chalmers university of technology, göteborg, sweden, 2001. [23] bredberg, j., turbulence modelling for internal cool ing of gas-turbine blades. 2002: chalmers university of technology göteborg,, sweden. [24] bredberg, j. and l. davidson, low -reynolds number turbulence models: an approach for reducing mesh sensitivity. journal of fluids engineering, 2004. 126(1): p. 14-21. [25] bredberg, j., l. davidson, and h. iacovides. comparison of near-wall behavior and its effect on heat transfer for k -omega and k-eps turbulence models in ribroughened 2d channels. in turbulence heat and mass transfer 3/nagano, y., hanjalic, k., tsuji, t. 2000 . [26] bredberg, j., s.-h. peng, and l. davidson, an improved k− ω turbulence model applied to recirculating flows. international journal of heat and fluid flow, 2002. 23(6): p. 731-743. [27] thongsanit, p. and t. mookum, numerical study of trailing edge cooling in a gas turbine blade. [28] hylton, l., et al., analytical and experimental evaluation of the heat transfer distribution over the surfaces of turbine vanes. 1983. [29] hasanpour, a., m. farhadi, and h. ashorynejad, hole configuration effect on turbine blade cooling. w orld academy of science, engineering and technology, 2011. 49(1): p. 240-244. article al-qadisiyah journal for engineering sciences 14 (2022) 197–000 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hibarf86@gmail.com (hiba arif jasim) https://doi.org/10.30772/qjes.v14i3.790 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. the formation of invisible architecture according to environmental tendencies techniques hiba arif jasi*, anwar subhi ramadan, aseel ibrahem mahmood university of technology, department of architecture, baghdad, iraq a r t i c l e i n f o article history: received 00 december 2020 received in revised form 00 january 2021 accepted 00 february 2021 keywords: invisible unseen architecture unobserved architecture immaterial architecture invisible sustainability a b s t r a c t increasing awareness of the need to take care of the planet and reduce the negative effects of human impact on the environment at the level of all aspects of life, including architecture has become essential. the invisible architecture and in accordance with the environmental tendencies appeared as one of the contemporary trends to be that formation that achieves blend with the environmental surrounding and based on techniques that reduce its appearance to emphasize the importance of the external environment and trying to return to nature and increase green spaces in a manner that reduces pollution to minimum level. therefore, this architecture is part of the site and not just an added part to it, as well as its quest to increase operational efficiency and to reduce its negative impact on the environment in addition to improving the built environment that enhances health and well-being of the user. many previous international studies highlighted various aspects of invisible architecture and the techniques and technologies for achieving them, noticing the limitation of arabic and local studies that dealt with this topic. this research aims to provide clear and comprehensive knowledge of the techniques of achieving invisible architecture in its environmental perspective with its multiple formations, which can be adopted effectively by the designer in general, and in a manner, that serves the reality of the arab and local experience. and in line with the local natural and urban environment to keep pace with contemporary global trends. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the signs of invisible architecture appeared in the various eras of history and since ancient times, despite not referring to them conceptually. where man adopted the first structural patterns, such as the cave, which was masked by mountains or hills and even within the ground, aiming to achieve shelter [1], and the holy qur’an mentioned the wonderful models of the buildings of the ancient nations and the various geometric shapes, such as the houses of thamud and the palace of the prophet suleiman. in the text of the noble verse: (you take for yourselves palaces from its plains and carve from the mountains, homes) (surat al-a’raf, verse 74), it was also stated in the text of the verse:(it was said to her: enter the palace, but when she saw it she deemed it to be a great expanse of water, and bared her legs. he said: surely it is a palace made smooth with glass. she said: my lord! surely, i have been unjust to myself, and i submit with sulaiman to allah, the lord of the worlds) (surat an-naml, verse 44). the edifice was made of transparent and reflective glass that freshwater was running under. in other words, it did not rely on the visual aspect only; but the sense of touch to perceive it, [2]. the interest also appeared during the ancient and medieval historical times using optical illusion to manipulate the dimensions of spaces, to pay attention to light and sound design, and influencing the perception of the recipient by finding the boundaries of space without the need for architectural elements such as walls, ceilings, and doors, as in roman temples, [3]. in addition to the use of mosaics and drawings, the spaces seem different from their true identities and the art of decoration (arabesque) that gives the impression of movement to a fixed body [4], [5]. in both western and islamic architecture, up to the architecture of the twentieth century, which was concerned with relying on the characteristics of the building material to communicate between http://qu.edu.iq/ https://doi.org/10.30772/qjes.v14i3.790 https://doi.org/10.30772/qjes.v14i3.790 http://creativecommons.org/licenses/by/4.0/ 198 author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–000 for the time being, invisible architecture is emerging as one of the contemporary global trends towards harmony with the surrounding environment, whether natural or artificial and achieving environmental sustainability in particular, in terms of the fact that architecture is much more than its physical construction, as it has another invisible aspect that is more vital and makes it associated with its surroundings as a part of it and not added to it, [8] so was the protected underground architecture that excavated the components of the earth from soil, rocks or caves to be part of the building elements and merge with it, to achieve protection and maintain energy efficiency increasing the green spaces [9] and controlling the relationship with the ground levels, which may be in direct contact with the outside or indirect contact, to mask the building and achieve security and safety and arousing the feelings of the recipient. [10]. on the other hand, the invisible architecture was found by adopting the method of camouflage and with the intention of disguise through the use of elements similar to the elements of the surroundings and the use of transparent materials, to achieve communication between the interior and the exterior, and blending with the surroundings [11] besides the use of each of the elements of the environment such as air and sound to create nonphysical boundaries that separate the interior from the exterior and characterized by being unstable, ephemeral, dependent on the senses of the recipient to perceive it [12], the adoption of media facades and atmosphere facades to mask architectural solidity transforming architecture from stability to movement, interactive dynamism with a view to the interaction between the recipient, interface and the environment, making it characterized by vitality and ambiguity [13], [14]. accordingly, it is clear that there is a multiplicity and diversity in terms of invisible architecture formations, techniques and technologies adopted in general, according to the environmental trend in particular in terms of striving to reduce the negative environmental impact and achieve both harmony and sustainability to create an architecture with distinctive aesthetic values and economical benefits that meets multiple functional needs, which formed an incentive for this research in order to clarify the techniques adopted in the formations of invisible architecture from the environmental perspective, which can be effectively adopted by the designer, and in order to serve the arab and local experience to catch up with contemporary global trends, so the research relied on the descriptive approach in analyzing prior knowledge and applied experience, by a sequential steps that begins with building a conceptual framework for each of the concepts of the invisible in general and in architecture in particular, in a way that determines its most important forms, and then forming a cognitive framework for the techniques adopted in the formation of the invisible architecture according to the environmental trend, secondly, to apply that framework on selected models from arab projects, third, to determine a set of conclusions and recommendations regarding the reality of the arab experience, and fourth, the possibility of adopting the knowledge presented in future local projects. 2. architecture and invisibility concept 2.1. define the concept of the invisible in general the invisible concept can be defined in the arabic language, by what contradicts it from the visible concept. considering that (in) received linguistically as being a noun meaning neither nor not, as in not clear, and the almighty’s saying: (but whoever is forced, neither desiring nor transgressing), meaning he who is forced is hungry, neither oppressive nor normal [15]. thus, the invisible refers to what is not under consideration, for it is what is neither observed, nor material, nor tangible, nor seen, nor perceptible [16]. in the english language, the concept is given as (invisible), and it indicates, according to merriam-webster’s dictionary, that it is by nature incapable of seeing, difficult to perceive by sight [17], while the oxford dictionary defines it through a set of synonymous meanings, it includes all of the following: (unseen, conceal, hidden, out of sight, undetectable and unnoticeable or unobserved) [18]. thus, it is clear that the concept is associated linguistically with two main aspects: the first, the act of intentional concealment, mask, disguise, or hiding, and the second, the product of the intended action, which is incapable of detected as shown in (fig. 1). figure 1 a model showing the visible and the invisible linguistically (source: researchers) idiomatically, the definitions of the invisible have varied with the multiplicity of opinions and trends of researchers in various fields of knowledge, as it refers in philosophy to everyone who is essentially hidden (what is essential) and it did not have an intentional act of concealment, except that it is felt internally or perceived and felt, or what is covered, masked, concealed, or hidden by an intentional act to be invisible, which is difficult to distinguish and perceive, but it can be perceived later after scrutiny [19], [20]. in physics, the invisible refers to the intangible elements that are not considered concealed, because they can be perceptually perceptible and are known as the elements of the atmosphere (light, air, sound, and temperature), and they can be controlled and manipulated to affect the recipient’s sense [21] by adopting advanced technology, it is possible to find intangible components that cannot be perceived or detected, by an intentional act of perceptual concealment, for each of the visual and sensory terms, for example, what has been focused on in strategic aviation techniques and increasingly within defense networks, to penetrate the enemy airspace by stealth aircraft [22]. on the contrary, the invisible in physics also refers to the unseen and unobserved bodies that are difficult to distinguish and perceive, but they are realized later after scrutiny, and are achieved by an intentional act of masking, hide, or disguise, and this is by relying on other bodies (such as forts and shelters) so the bodies are unseen, or through camouflage, so the author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 199 bodies are unobserved for the purpose of shelter, depending on the shape of the body and its background, so they are blended with the surrounding environment, which was invested militarily for the first time in the midnineteenth century, such as coloring clothes, or using river mud to dye themselves, so they become unnoticed or unobserved [23], or masking based on the physical properties of objects that allow light to pass through them and become transparent objects, or by manipulating the light path through the use of reflective mirrors [24], [25]. (fig. 2). using mirrors to make an object invisible [107] using camouflage in military operations [108] figure 2 – invisibility in physics the invisible in biology refers to the organisms that are difficult to distinguish and perceive, but are realized later after scrutiny, and are achieved by an intentional act of mask or hide. this is done by relying on objects and elements found in nature (such as plant leaves, rocks, etc.), so that the organisms are unseen for shelter and hunting, or the adoption of camouflage so that the bodies are unobserved in blend with the surrounding environment for protection by relying on the shape of the body and its background, and coloring and reincarnation, such as what merges the owl with the background and takes on the shape of the tree trunk, as well as for the frog and the caterpillar with the leave [26]. octopus species can become translucent or manipulate the light path through the reflective outer layer into unobserved bodies as in a sea worm that produces a dazzling display of light in a process known as bioluminescence, confusing predators and those who think they are looking at sunlight the spotted striking the surface of the water [27]. (fig. 3). owel camouflaged with tree [109] the ability of a glass octopus to turn transparent [110] figure 3 – invisibility in biology the invisible in the arts refers to the objects that are difficult to distinguish and perceive, but they are realized later after scrutiny, relying on optical illusion, which is one of the techniques of creativity, as it deliberately manipulates the awareness and mind of the recipient, so the objects appear in a way other than what they appear as in visual art (op-optical art) [28]. as the invisible concept appeared in the performing arts and the cinematic field, visual effects had a significant impact on the development of the concept, which refers to techniques used by filmmakers to show what is not real, as something real and existing [29]. in the past, these effects relied on simple and traditional techniques, including masking the features of the actor’s character by disguise, especially in the field of fashion and makeup. sometimes the character needs to blend with the design of the scenes or the directing choices, so attention is given to highlighting the elements that make the character in its unseen form [30], then there were many devices and programs in this field, and among the visual effects that make the body look unobserved by disguise is the motion capture, which allows the actor to be unobserved by disguising any character, and this is by wearing special clothes, linked to a group of devices wired when the actor moves, these devices capture the movement and convert it into keyframes on the graphics programs [31]. as for the visual effects that make the body in its intangible form, it is the green or blue screen, or what is known as chroma, which is it is the construction and design of the surrounding environment on the graphics programs and then merging it with the scene depicted on a green or blue background [29]. it is clear from all linguistic and idiomatic definitions that the invisible has many forms that depend on several techniques to achieve it. including the concealed forms associated with the human feeling, which are essentially concealed, meaning that no intentional act of concealment, mask, disguise, or hide occurred on them, and the unseen form of the body that depends on other bodies to masked it without any changes to it. as for the unobserved form, it depends on a change in the characteristics of the body or external influences that lead to a change in the body itself. as for the intangible form, it is real and existing, but it does not have a physical presence, but it can be perceived. 2.2. invisible architecture definition studies have put forward several definitions of invisible architecture, as they defined it as the architecture of the cover, which depends on the use of the nature of the land to build a shelter for the human being, to protect against climatic conditions [10]. it is also known as the architecture that intends to mask the building by relying on other structural elements [5], [12]. while other studies defined invisible architecture as those whose buildings try to be hidden from the view of everyone and reduce the appearance of what is being built, through the development of a series of operations such as camouflage and the use of optical illusion so that it is difficult to distinguish them despite their physical presence, or blending the edges of the building with the elements of the external spaces, making the shape of the building difficult to distinguish, when the architect wants to highlight the features of something else, such as the surrounding natural features and blend with them [6] [32]. it can also resort to mimicry along with optical illusion, and uses various technologies such as screens, mirrors (including water mirrors and reflective surfaces in general), video cameras, etc., to make its buildings difficult to distinguish, even if they are huge. which tends to be in blend with its surroundings in which it is located. [33], an architecture that can depend on the nature and characteristics of materials and the interaction of possible boundaries between man and technology, such as floating or cloud architecture, which is transparent, light, and melting with the site, to adapt to the environment [34]. the inclusive intelligence research institute (ciri) defined invisible architecture as those that can be perceptually perceptible with the help of technology, and take light, color, sound, and smell as elements to define space and create sensory spaces, like its tectonic counterpart represented by walls, ceilings, and doors. where the location, shape, and boundaries to create, whether they are public buildings or homes, or even at the level of designing outdoor spaces. it operates in a way that the biological senses are not directly aware of and affects the minds and behaviors of the viewer more than visual buildings [35], [3]. where its definition is related to the so-called immaterial materiality, which is the possibility of building material things so that solid bodies are formed in a stationary state. 200 author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 however, it gives the impression of a state of movement, and thus generates many perceptions throughout the duration of its movement and defines media buildings [36]. thus, the immaterial form of architecture depends on sensory influences to be perceptible, using elements of the atmosphere such as air, light, and sound to complement the material experience of architecture, to create walls, ceilings, and furniture instead of traditional building materials, and the requirements to achieve them include the use of techniques and technology of materials and tools [37], [38]. it is considered one of the contemporary trends towards the future of sustainable design, to design buildings that reduce energy use and greenhouse gas emissions, to improve the sustainability of the built environment while supporting the architectural aesthetic of efficient, beautiful, and integrated buildings [39]. it is clear from the foregoing that the invisible architecture is the architecture of sensory perception based on the intentional action of the designer in terms of hiding, mask, and disguise, and it included the following forms, see (fig. 5). • unseen form: it is the form of invisible architecture that relies on other elements to mask it, which may be structural elements or those elements from the environmental surrounding for the purpose of protection, and it cannot be perceptually perceptible only after scrutiny and focus later. • unobserved form: it is the form of invisible architecture that depends on the physical properties of its components and according to camouflage and optical illusion to blend with the environmental surrounding, and it is difficult to perceptible it only after scrutiny and focus later. • immaterial form: it is the intangible form in invisible architecture that depends on the material and kinetic energy to create the boundaries of the building like its tectonic counterpart, to transform architecture from fixed and stable material existence to a moving immaterial existence that requires sensory perception. figure 5 a model showing the forms of the invisible in architecture (source: researchers) 3. the invisible architecture in its environmental perspective the invisible architecture in its environmental perspective is based mainly on trying to blend with its environmental surroundings, which includes: • the ecological environment: it is all the living and non-living elements in which man has not had any interference. it is known as pure nature, which affects the lives of living organisms directly or indirectly, such as (seas, deserts, terrain, climate, plants, and animals). • built environment: it is the physical and urban structure built by man and includes all facilities, whether residential, industrial, or service, and even the natural man-made ones, which work to organize societies and serve human needs, through systems integrated social, political, economic, cultural, educational, moral, technological, and urban [40] [41]. accordingly, it’s defined as it is the architecture that compositionally depends on the unseen, unobserved, and immaterial architecture in order to reduce its appearance to a minimum, which is difficult to perceive and aims to blend with its environmental surroundings by relying on several techniques and what it contains technology and materials included within it with contemporary trends of sustainability, conservation of energies and resources, as well as enhancing aesthetic, functional and sensory qualities. this research has invested many previous studies and international and arab applied projects, for determining the techniques adopted in the formation of invisible architecture in its environmental perspective, in a manner that is consistent with the goal of the research, and these techniques were classified according to each of the following: 3.1. techniques of the unseen formation of invisible architecture in the environmental perspective they are those techniques that are adopted to reduce the appearance of the building with the intention of mask and hiding and by relying on other elements, which may be natural or artificial (structural or non-structural), while preserving the original formal characteristics of the building unchanged to achieve protection from environmental conditions in the main, so that it is difficult to perceptible except after scrutiny and focus later, to include all the following: 3.1.1. merging with landscape technique this technique refers to the merging of elements of the building with the elements of its surroundings so that the building appears as part of or as an extension of the landscape or the surrounding outdoor spaces, and the effect of this method is very strong for architects who want their buildings to appear as a result of their surroundings [42], integration with the site is also associated with criteria such as biophilic design, green architecture or ecodesign to achieve sustainable design, as well as the integration of historic urban sites with contemporary built areas [43]. this technique relies on a set of technologies as follows: landscape intersection technology: this is based on the melting and fading of the building lines with the site topographic lines [44], as in the sancaklar mosque in istanbul. underground architecture technology: this technology depends on the containment and mask of the building through burial and the construction of the entire building under the surface of the ground, or the pit by constructing the building close to the surface of the ground or sculpting in the mountains in a similar way to caves [45] [46] [47], as in the cave-like house in greece. submerged under water architecture technology: where the whole or part of the building is submerged below the water level with the intention of masking [48], as in the underwater discovery center in australia (fig. 6). author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 201 sancaklar mosque in istanbul [93] cave-like house in greece [81] underwater discovery center in australia [93] figure 6 a model showing merging with landscape technique 3.1.2. wrapping technique the technique of wrapping in buildings depends on what is known as the language of layering, where the building consists of the main layer represented by the original building mass that is intended to be made invisible, and the secondary layer, which is a material layer that works to wrap the building either by coating it or surrounding it, which makes the building mass invisible without affecting the shape of the original mass of the building, and helps to protect from the surrounding environmental conditions in addition to enriching the building and creativity [5]. this technique relies on a set of technologies as follows: coating technology: it is based on coating the surfaces of building units either with membrane components coating such as cloth or plastic or coating with green walls one of the patterns of biophilic design, which are basically vertical walls covered with plants and natural elements as well as some water delivery systems, or by adopting screen coating, which uses a curtain layer that is wrapped on the building envelope, this technology works to control solar energy by reducing glare and heat gain, and is also used to achieve privacy, insulation and visual comfort. [12] [49], [50] [51], as in the ahn jung-geun memorial hall in south korea and citicape house in london. façadism technology: it is considered one of the controversial technology to preserve the context of the urban environment, which means demolishing the old building historically and creating a new building for new purposes or function, while keeping the old facade around it to mask the modern building [52] and benefiting from the facade by controlling shade and light and providing natural ventilation due to the distance between the facade and the modern building, which reduces heat gain and achieves visual and thermal comfort [53], as in the national provincial bank in london. surrounding technology: it is based on surrounding the original building with a secondary mass, where this construction technology is simulated to russian dolls, by designing one building inside the other, for environmental, privacy, security, or service reasons [12] and this technology can be achieved through the building in the building. in this technology, the original building is inside a secondary building or structure, where the original building maintains its characteristics, while the secondary building works to control solar energy and keep the building cool as well as providing the new shape and additional space [54], as in the shed center in chicago, or the adoption of an exterior structure that allows shading and self-ventilation of the building [55], as in the broad museum in los angeles, and kinetic facades can be adopted with the intention of completely or partially masking the building to be adapted to the environmental surroundings. it aims to respond to changing environmental conditions and enhance the aesthetic qualities [56][57], whether those facades are sliding, folding or tracking, as in the sdu kolding in denmark (fig. 7). ahn jung-geun memorial hall in south korea [98] citicape house in london [93] caledonian road in london [53] the shed center in chicago [54] broad museum in los angeles [98] sdu kolding in denmark [98] figure 7 a model showing wrapping technique from all above, it is possible to summarize the unseen formation techniques for the invisible architecture in the environmental perspective and the technologies included in (table 1). table 1 the unseen formation techniques and technologies for the invisible architecture in the environmental perspective (source: researchers). formation techniques formation technologies merging with landscape landscape intersection technology melting and fading the building lines with the site topographic lines underground architecture technology burial, pit, sculpting submerged architecture under water technology whole or part of the building submerged below the water level wrapping coating technology coating with membrane components such as cloth or plastic, green walls, screen coating façadism technology architectural preservation of old facades in buildings with new buildings built behind them surrounding technology building in building, exterior structure, kinetic facades 3.2. techniques of the unobserved formation of invisible architecture in the environmental perspective techniques that are adopted to reduce or delay the process of detecting the building with the intention of mask and disguise by relying on the physical characteristics of the components of the architectural form essentially to achieve blending with its environmental surroundings in the basic degree, 202 author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 so that it is difficult to realize it only after scrutiny and focus later, to include all the following: 3.2.1. camouflage technique camouflage is defined as a tactical concept as one of the techniques of formal adaptation of the body to reduce visual detection or recognition of the object by the observer and to play with its perceptions [58]. by studying the technologies of the camouflage technique, the architects were able to take advantage of the concept of interdependence between the shape of the building and its surroundings, which works to reduce what appears from the building and which delays detection or recognition of the shape of the building, making it blend with its surroundings, focusing on the importance of the environmental surroundings, whether natural or an urban landscape [59]. this technique relies on a set of techniques as follows: dazzling camouflage technology: this technology depends on the factors of dazzling and dispersion with the intent of masking, where complex patterns of geometric shapes or others are used in contrasting colors, and intersecting with each other, thus giving greater confusion and difficult to distinguish the shape of the building, and this technology can be achieved through drawing directly on the surface of the building envelope, either by coloring the building in a color similar to its surroundings or by drawing shapes similar to its surroundings, so it is difficult to distinguish the shape of the building in order to focus on the importance of that surroundings [60], as in drawing the sky on the building by the artist benjamin lozninger, or by adopting digital camouflage patterns in pixels in a way similar to the speckled textures and rough borders found in nature that are used in military equipment and clothing, in order to distort the shape of the building [61], as in digital camouflage pattern (cadpat). mimicry technology: the camouflaged building in this technology looks like something else, and it depends on the nature of the surrounding site, and this is called what is known as stealth, and this is not intended to escape from the area, place and site, but to involve a relational mechanism with the environment that surrounds the architecture at different levels [11], and this technology can be achieved through either disguise, where the building uses the properties of the surroundings such as shape and material [58] to influence the perception of the recipient [62], as in the stone house in portugal, or the building copying the shape of the surroundings, which leads to a change in the shape of the building according to the change of the surroundings around it, and based on each of the photographic prints [63], as in the public toilet in amsterdam and the reflective surface [3], as in cira center tower in philadelphia and the mirror garden in china, and the transparent surface as in apple store in new york as well as the light reflecting (led) technology[64], as in the infinity tower in south korea (fig. 8). benjamin lozninger drawing [106] digital camouflage pattern (cadpat) [63] stone house in portugal [98] public toilet in amsterdam [93] cira center tower in philadelphia [98] mirror garden in china [98] apple store in new york [93] infinity tower in south korea [105] figure 8 a model showing the camouflage technique 3.2.2. optical illusion technique it is a technique used for deception and entertainment to manipulate the recipient's perception of reality, and impressions of space and structure can be controlled by changing the proportions and appearance of building elements [65]. it is also considered one of the dynamic arts, as it transmits kinetic energy in the form, through the participatory relationship between the eye and the mind, which modifies the image of the figure in a way that is different from its real form [66] and this helped improve the quality of the internal environment by controlling access to sunlight and reduce heat gain, and this technique depends on a group of technologies as follows: color illusion technology: it depends on the factors of optical tricks and confusion, and both color and light are among the main effects and technologies on which the optical illusion technique depends to disguise itself in another form to improve the shape or image of old buildings or those that contain some defects so as not to affect the scene of the environmental surroundings [3], this technology also uses dichroitic and holographic materials can change color when viewed from different angles [67] [68]. kinetic illusion technology: it relies on visual tricks that suggest a sense of movement, and this is produced using wavy and intersecting lines and overlapping circles [4], which makes it difficult to perceive the true shape of the building. it aims to control the penetration of daylight into the interior spaces as well as to achieve pleasure with the intention of disguising itself in a changing form [69], as in galleria center city in south korea (fig. 9). color illusion technology [104] holographic materials [67] galleria center city in south korea [98] figure 9 a model showing optical illusion technique from all above, it is possible to summarize the unobserved formation techniques for the invisible architecture in the environmental perspective and the technologies included in (table 2). author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 203 table 2 the unobserved formation techniques and technologies for the invisible architecture in the environmental perspective (source: researchers). formation techniques formation technologies camouflage dazzling camouflage based on the melting and fading of the building lines with the site topographic lines mimicry disguise by adoption of the properties of the perimeter (shape and material) copy by photographic prints, reflective surface, translucent surface, light reflecting (led) optical illusion color illusion, kinetic illusion 3.3. techniques of the immaterial formation of invisible architecture in the environmental perspective techniques that transform architecture from its material existence to immaterial moving existence by relying on intangible (atmospheric and kinetic) elements to create the boundaries of the building essentially to achieve both interaction with the environmental surroundings and sensory comfort, which thus requires a sensual perception of it, to include as follow: 3.3.1. inversion of atmosphere technique it is a technique based on decreasing the solidity and stability of the architectural form, as it creates boundaries for the architectural building that are like its tectonic counterpart, and it also shows the vital relationship between the interior and the exterior, through what it contains of elements such as air, water, light, heat, and sound [70]. this technique relies on a set of technologies as follows: light architecture technology: light is invested as a building material in architecture by framing the surface that defines the shape of the building or finding boundaries that are immaterial nature and separate the interior from the exterior while providing a sense of openness to the outside [3], as in the memorial tribute light in new york. blur or cloud architecture technology: it is based on the use of thin or thick mist mass (which is a kind of cloud resulting from the condensation of water vapor and its flow through the air), as structural boundaries (walls) by installing a computer-guided water pumping system that sprays small water particles in the air, which may lead to difficulty in seeing and thus reduces the solidity and stability of the architectural form [12], as in the blur building in expo 2002 in switzerland. water walls or curtain technology: it is based on the use of water according to the usual or digital methods to make a wall or a curtain to find boundaries for the internal or external spaces and in a way like the work of the traditional wall, which contributes to softening the surroundings and influencing the feeling of the recipient to interact with it [71], as in ambient sound technology: it is based on the design of walls or boundaries that enable listening and feeling the sound vibrations, which leads to the reduction of sound pollutants in the environment and brings the recipient into an active relationship with his environmental surroundings [3], as in time square in new york by max neuhaus (fig. 10). memorial tribute light in new york [103] blur building in expo 2002 in switzerland [12] digital water curtain [71] figure 10a model showing inversion of atmosphere technique 3.3.2. media architecture technique media architecture is defined as-built structures in which materials with dynamic properties are mixed, that allow dynamic or interactive behavior to facilitate communication with the audience. and in media architecture, in media architecture, the relationship between architecture, media, external spaces and the idea of visual interaction and audience involvement is emphasized, as it is sometimes accompanied by environmental, artistic, or social content through which visual, audio, and dynamic messages are conveyed to the viewer and creating interaction between the building and its surroundings [72]. this technique relies on a set of technologies as follows: media facades technology: in it, layers of individually controlled lights are adopted, and woven with the building structure to act as a dynamic panel for texts, graphics, video animations and large screens associated with production and computer technologies [73], so the virtual representation of the architecture, by removing its material property, so dynamic images replace static structures and create the interaction between architecture, and its surroundings and the viewer [74], and the various forms of technologies used in contemporary media facades that are concerned with the environment and energy conservation depend on the way in which they are these technologies are integrated with the facade, either as a subsequent addition to it, or to be integrated with the components of the facade, which achieves visual comfort, as it allows penetration of daylight and visual openness from the inside to the outside, to include display facades that communicate with the environment [75], as in the dexia climate tower in brussels, sustainable media facades whether integrated with led technology and photovoltaics, etfe-enabled, responsive, or transparent displays e. [76] [77] [78] [79]. media interiors technology: mainly based on interiors that rely on the effectiveness of the cinematic experience, with the ability to expand themselves beyond their surface appearance. where a material structure confronts an immaterial structure using media such as video, film, display screens and led technologies to create forms aimed at solving the concept of a world of static materials that expands the user's perception of reality, transcends, and presents an entirely new dimension of creative architectural expression [65], this technology can be achieved using interactive surfaces, digital interior and virtual reality [80] [81] [82]. (fig. 11). 204 author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 dexia climate tower in brussels [78] using digital interior [81] figure 11a model showing media architecture technique from all above, it is possible to summarize the immaterial formation techniques for the invisible architecture in the environmental perspective and the technologies included in (table 3). table 3 the immaterial formation techniques and technologies for the invisible architecture in the environmental perspective (source: researchers). formation techniques formation technologies inversion of atmosphere light architecture, blur or cloud architecture, water walls or curtain, ambient sound media architecture media facades display facades that communicate with the environment, sustainable media facades, transparent displays media interiors interactive surfaces, digital interior, virtual reality 3.4. techniques of the invisible sustainability architecture formation techniques that are based on achieving sustainability through their integration with the techniques of architecture formations that are not visible in their environmental perspective (unseen, unobserved, immaterial), one or more, to achieve environmental goals in the first place, as well as goals related to creating healthier urban environments, luxury and comfort for its occupants in both internal and external configurations, so that the architecture is characterized by invisible sustainability, as energy-efficient buildings [83]. these techniques and the technologies they include can be identified in the following: 3.4.1. passive design technique the concept of passive design revolves around taking advantage of natural energy flows to maintain thermal comfort, and the choice of passive design techniques depends mainly on the local climate where the project is located, as the integration of these techniques contributes to transforming the building envelopes into a barrier between the natural climate and the virtual climate to meet the required level of comfort humanity [84]. this technique relies on a set of design considerations, such as building orientation [85]. building shape and mass [86] and choosing materials (choice of materials) [84]. in addition to considering, the design of outdoor spaces (landscaping) [87]. 3.4.2. off-grid design technique an off-grid technique has emerged as one of the solutions that allow living to be self-sufficient in terms of energy and water as well as for many people in terms of food, where off-grid traditionally refers to not being connected to the electrical grid and the building being able to produce electricity and/or heating itself in order to meet its own needs, but can also include other utilities such as water, gas and sewage systems, and can range from residential homes to small communities [88] [89], and off-grid technique include main components: generation of electricity, energy storage, back up units, devices in a house that consume electricity, and a connection to an electric grid line when present, and simulation package (demkit) [90]. this technique relies on a set of technologies by which invisible sustainability can be achieved, including: renewable energies: a natural sources of energy that are constantly renewed, represented by the sun, wind, geothermal heat, water, biomass, and oceans [91], and this can be achieved through either a single off-grid system, where it involves the use of a single source of renewable energy, or multiple off-grid system, in which more than one source of renewable energy is combined. intelligent building management system technology: where the entire building structure is managed through an intelligent building management system using modern techniques and technology to balance the work of the building at all times and thanks to the external and internal sensors, the system responds automatically to external conditions, and will ensure safety, energy efficiency and maximum comfort while managing resources such as water in a smart way, as well as on the possibility of producing vegetables and herbs at a time when the concept of vertical and horizontal farms is increasing outside and inside [92], as in disappear retreat in usa (fig. 12) disappear retreat in usa [83] figure 12a model showing off grid design technique from all above, the techniques of the invisible sustainability architecture formation and the technologies included in it can be summarized in (table 4). author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 205 table 4 the invisible sustainability formation techniques and technologies for the invisible architecture in the environmental perspective (source: researchers). formation techniques formation technologies passive design building orientation orientation of the building appropriate to solar radiation and wind movement building shape and mass minimizing outdoor surfaces exposed to climatic conditions fixed or moving shading tools choosing materials that are resistant to different climatic conditions landscaping off grid design adopted renewable energy singular off grid system multiple off grid system intelligent building management system water efficiency provide food 4. the superimposed formation for environmental invisible architecture in the previous paragraphs, the multiple techniques that are adopted in the formations of environmentally invisible architecture, which are achieved at internal and external levels in architecture and with various materials, and according to the objectives to be achieved in each of them, were identified. the presence of these formations in their multiple techniques separately does not necessarily negate the possibility of adopting more than one formation in a single architectural project, which contributes to creating an invisible architecture on the environmental level, as it is possible to combine more than one formation within an integrated unit, and perhaps the project to expand the louvre museum in paris is a good example as the part of the museum under the surface of the earth refers to the unseen formation, while the transparent pyramid part refers to the unobserved formation of the environmentally invisible architecture. the same method was adopted in the apple fifth avenue building in new york (fig. 13), which combines several formations of environmentally invisible architecture, as the building was designed underground, which indicates the unseen formation of environmental invisible architecture, while the aboveground part of the building is designed in the form of a transparent glass cube, and the floor surrounding the cube includes circular elements that transmit natural light to an underground level and are coated with a reflective material to reflect the perimeter of the building, and glass walls were used inside to give more space to space the interior, which achieves the unobserved formation of environmental invisible architecture. the interior ceiling is designed to change to match the color temperature outside as thousands of leds and sensors make the store glow, from bluish white in the morning to golden later in the day, and fruit trees are planted inside to achieve harmony with nature, which indicates the use of the intelligent supervision system for the building, thus achieving the formation of the invisible sustainability architecture [93]. this superposition can be represented in (fig. 14). apple fifth avenue in new york [93] figure 13a model showing the superimposed formation for environmental invisible architecture figure 14 representation of the theoretical framework for the formations of environmentally invisible architecture, source (researcher) 5. practical study the presentation of the previous propositions emerged from the global interest in designing the invisible architecture according to the environmental perspective as one of the contemporary trends, and in line 206 author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 with the increasing interest in trying to blend with the environmental surrounding (natural and urban), but arab knowledge and experiences in general and local experiences in particular, did not pay attention to that aspect as it should be parallel to the global interest, so it will be possible to determine the level of application with arab models, as there are no local models so far, with a focus on models from the arab gulf countries, due to the interest of these countries in adopting the latest trends as well as taking into account the advanced environmental solutions, in a way that enables investment these experiences are to create distinctive local experiences, in addition to clarifying the multiple ranges within which it is possible to develop the arab experience and in line with the advanced global experiences in this regard. the research supposes the adoption of the arab experience in the context of its realization of the environmentally invisible architecture, multiple techniques in its formations, with a focus on the techniques of the unseen formation and invisible sustainability architecture formation. various sources with photos and illustrations. 5.1. project selection after representing the level of application by contemporary arab projects (in the gulf countries in particular) was determined, and to achieve the purpose of the research is investigating the specificity of arab architecture’s dealing with the environmentally invisible architecture, projects will be selected to direct the application process, as this choice was based on each of the following: • the diversity of structural patterns in the projects, as the previous propositions showed the interest in designing the environmentally invisible architecture without being restricted to a specific structural pattern and to serve multiple goals. • these projects are distinguished by their great interest in the adoption of invisible architecture formations, and their consideration of the important attempts in dealing with the environment. • availability of sufficient information and plans for the selected projects. 5.2. project description and analysis according to the above paragraph, five arab projects were selected, represented by: 5.2.1. o-14 tower in dubai united arab emirates the project is a commercial tower designed by (reiser + umemoto, usa) and completed in 2010, consisting of (22) floors, characterized by (1326) slots distributed randomly and varying in size throughout the entire external structure, and the tower includes more than (27,900) square meters of office space is located along the dubai creek in the business bay district of dubai, occupying a prominent waterfront location. (o-14) was named after the plot, and it is considered one of the first towers to appear on the skyline of business bay. the project generated exceptional international interest in the architectural press, as it is among the first innovative designs to be built among a sea of public office towers that have become the standard in dubai's current building boom [94]. the tower was designed using exoskeleton technology, which is based on surrounding the main glass part of the building with an external structure, perforated from the abstraction of the shape of the arabic lattice to work as a contemporary mashrabiya, so that the passive design is essential in it, through the adoption of elements the perforated shell in shading the building, as well as achieving natural ventilation according to the chimney effect as a result of the space between the external structure and the main part [95], (fig. 15). figure 15 – o-14 tower in dubai united arab emirates [95] thus, the wrapping technique was adopted to find the unseen formation of the environmentally invisible architecture, by using the technology of surrounding the main mass of the tower with an external structure. the passive design technique was also adopted as one of the techniques of the invisible sustainability architecture formation by considering the external structure as fixed shading tools, the chimney improves the quality of the internal environment, and takes advantage of the longitudinal mass shape of the building to reduce the surfaces exposed to the sun as well as to face the movement of the wind. 5.2.2. the doha tower in qatar doha tower is the fifth largest tower in doha with an area of (110,000) square meters. it was awarded the best tall building in the middle east and africa by the council of tall buildings and urban accommodation in 2012. it was designed by architect jean nofal and completed in 2012, as it reflected the language of islamic architecture design through the mashrabiya, given that qatar has a hot desert climate and in summer the average temperature can exceed (38) degrees, and there is almost no rainfall, the kinetic façade of doha tower, with its complex geometric pattern of four layers, was designed to function as the mashrabiya [96]. the plan of the tower is circular in diameter (45 meters) with a perimeter structural system that allows better controlling the lighting of the interior spaces, it is crowned with a dome that ends with a light tower at a height of (231.50) meters, and a huge lobby rises from the ground floor with a height of (112) meters to level (27) [97], (fig. 16). figure 16 – doha tower in qatar [97] concluding, the adoption of wrapping technique to find the unseen formation of the environmentally invisible architecture, through the use of both the surrounding technology and the responsive sliding kinetic facades that follow the path of the sun, and the passive design technique was adopted as one of the techniques of the invisible sustainability architecture formation by considering the facade kinetic as mobile shading tools with a smart system (technological mashrabiya), and taking advantage of the author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 207 longitudinal mass shape of the building to reduce the surfaces exposed to the sun as well as facing the movement of the wind. 5.2.3. wasit wetland center in sharjah, united arab emirates the environment and protected areas authority in sharjah, in the united arab emirates, referred the project to the architectural studio (xarchitects) in dubai, where wasit reserve was originally a sewage and waste dump, and the rehabilitation process for the damaged ecosystem began in 2005, where 40,000 square meters of rubbish were removed, 35,000 trees replanted, land healing from toxic chemicals, unique salt flats and coastal sand dunes preserved, home to 350 bird species, a landing area for 33,000 migratory birds and a breathing lung for the city of sharjah. the site center was set up to continue protecting the natural environment, educating people about the richness of the wetland ecosystem, and providing information about birds that frequent the area and other wetland areas in the emirate [98]. the architecture of the center merges with its surroundings and uses the existing topography to reduce the visual impact on the landscape. when visitors arrive, an underground path leads them to a linear gallery, and a fully transparent wall allows visitors to experience and become a part of the natural environment of the birds. rainwater that collects on the ceiling has also been tapped into spigots that have been carefully integrated to blend in with the surrounding elements [99] (fig. 17). figure 17 – 5.2.3. wasit wetland center in sharjah, united arab emirates [98] thus, the merging with the landscape technique was adopted to find the unseen formation of the environmentally invisible architecture, through the use of underground architecture technology based on pit the construction at a level close to the surface of the earth and in closer contact with external spaces and focusing on them, and passive design was also adopted as one of the techniques of the invisible sustainability architecture formation through the form of mass and the reduction of surfaces exposed to the external environment. 5.2.4. maraya center in alula, saudi arabia kingdom the maraya building is in the northwestern desert of the kingdom of saudi arabia, designed by (giò forma studio associato s.r.l.), setting a record for the largest reflective building on earth, and a record for construction time, which was completed in just two and a half months (2019). it is a multi-purpose hall for concerts and entertainment and is a destination of global importance with (200,000) years of human history and culture at the crossroads of ancient civilizations. the project was designed based on the translation of the arabic word “maraya” in the form of a mirror or reflection, where the past and the future meet together at the same moment to add another level of awareness, pointing to the presence of amazing ancient tombs only 22 km from the new building, and the mirror is a way to create a dialogue between nature, history and the future, where visitors are truly amazed by the mirrored effect and the way it perfectly blends and reflects its surroundings. the building consists of a giant cube of mirrors adapted to withstand harsh environmental conditions, with a subtle curvature of the facade so that from a distance the building appears as a shimmering mirage of the surrounding panorama as it aims to focus on it, but as visitors approach, they see a perfect reflection of themselves [100] [101] (fig. 18). figure 18 – maraya center in alula, saudi arabia [100] thus, the camouflage technique was adopted as one of the unobserved formations of the environmentally invisible architecture techniques, using copy technology with the reflective surface to focus on the importance of the surrounding environment, and passive design was adopted as one of the techniques of the invisible sustainability architecture formation using materials resistant to harsh climatic conditions. 5.2.5. toda in dubai, united arab emirates it is considered the first unique theater for digital art in the united arab emirates designed by (european digital house), which opened in 2020, which offers its visitors to experience art differently when visiting the exhibition, and its uniqueness lies in the modern and immersive way to discover the masterpieces of the most famous artists world as well as contemporary digital artists by strolling through an art space, where unforgettable photos can be taken during the show. stunning digital shows combine cutting-edge technology and art, accompanied by stunning music, visual effects, and surround sound. covering more than 1,000 square meters, viewers can also explore inspiring and entertaining activities such as live concerts, master painting classes, virtual reality technology, and immersive shows. the project relied on media architecture, which included the use of virtual reality displays and the use of large high-definition screens with (led) technology on the walls, ceiling, and floors with high-quality surround sound. projecting 360-degree images on all surfaces creates a unique viewing space that makes viewers feel like they are part of an immersive artwork [102] (fig. 19). figure 19 – toda in dubai, united arab emirates [102] 208 author, author /al-qadisiyah journal for engineering sciences 14 (2022) 197–210 thus, the media architecture technique has been adopted to find the immaterial formation of the environmentally invisible architecture, through the use of virtual reality technology in designing virtual environments for the environmental surroundings such as forests and living organisms, and digital interiors technology based on the integration of digital technology with (led) screens in the roof’s interior display spaces. 6. results the results of the application revealed in general according to (table 5), the adoption of the unseen formation of the invisible architecture from the environmental perspective by (60%), and the unobserved formation of the invisible architecture from the environmental perspective by (20%), and the immaterial formation of the invisible architecture from the environmental perspective by (20%), while the formation of the invisible sustainability architecture was approved by (80%). as in (fig. 20). the results of the application also revealed a discrepancy in the adoption of the techniques of each of the unseen, unobserved, immaterial, and invisible sustainability architecture formations of invisible architecture in the environmental perspective. where the results of the application showed the adoption of the elected arab projects by the unseen formation of the environmentally invisible architecture techniques represented by merging with the landscape by (33.33%) and the wrapping by (66.66%), while the unobserved formation of the environmentally invisible architecture techniques represented by camouflage at a percentage of (100%), and on the adoption, the immaterial formation of the environmentally invisible architecture techniques represented by media architecture at a percentage of (100%), and the results showed the adoption of the invisible sustainability architecture formation techniques represented by passive design (100%) and off-grid design (25%), as shown in (fig. 21). table 5 application of the invisible architecture formations techniques from its environmental perspective in the selected projects, (source: researchers). formations techniques projects elected for application a b c d e unseen formation of environmentally invisible architecture merging with landscape 0 0 1 0 0 wrapping 1 1 0 0 0 unobserved formation of environmentally invisible architecture camouflage 0 0 0 1 0 optical illusion 0 0 0 0 0 immaterial formation of environmentally invisible architecture inversion of atmosphere 0 0 0 0 0 media architecture 0 0 0 0 1 architecture of invisible sustainability formation passive design 1 1 1 1 0 off grid design 0 0 1 0 0 figure 20 application of the approved formations of the invisible architecture in the environmental perspective, (source: the researcher). figure 21 application of invisible architecture techniques in the environmental perspective, (source: the researcher). thus, the results are consistent with what the research assumed about the specificity of the arab experience in its application of environmentally invisible architecture. 7. conclusions • diversity has emerged regarding techniques that can be adopted in finding invisible architecture formations for their environmental perspective, in terms of the techniques of each unseen, unobserved, immaterial, and even invisible sustainability architecture formations. • it is possible to adopt more than one technique and for more than one formation of environmentally invisible architecture within the same project within an integration that serves several environmental goals and according to functional and contextual requirements. • the practical study, in general, showed the adoption of the arab experience, an integration between the techniques of each of the formations (unseen, unobserved, immaterial, and invisible sustainability architecture) of environmentally invisible architecture. • the arab experience focused on adopting the techniques of the unseen formation of invisible architecture in the environmental perspective, especially wrapping and merging with the landscape through the pit technology under the surface of the earth, and in accordance with the local specificity of the building techniques adopted in its traditional architecture, which was based on the adoption of mashrabiyas and even underground construction. • the arab experience relied on the technique of passive design to achieve the invisible 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of inconel 600 alloy by electroless ni-p deposition hassan. h. masallb a*, kadhim f. al-sultani a, abdul raheem. k. abid ali a a college of materials engineering, university of babylon, hilla, iraq a r t i c l e i n f o article history: received 18 november 2019 received in revised form 22 october 2019 accepted 30 october 2019 keywords: electroless plating ni-p x-ray diffraction inconel 600 tafel extrapolation a b s t r a c t the use of electroless ni-p plating (en) coating has attracted a surprising interest in the most recent years. many useful characteristics of the electroless-plating method have created many benefits in different industries such as oil, gas, electronic, automotive, aerospace, and chemical. some of the highlighted properties of such a method are superior corrosion resistance, superior mechanical properties, and uniform thickness of the coating as well as good surface finish properties, good adhesion characteristics, and a wide range of thickness. in this paper, electroless plating has been applied in a (ni-p) bath at two different times of 2 and 3 hr respectively. after the plating, a heat treatment at 400 °c for an hour under vacuum 10-4 torr has been done. the prepared samples were characterized by energy dispersive spectroscopy, x-ray diffraction, and scanning electron microscopy (sem). in addition, micro-hardness and corrosion rate following tafel extrapolation in two acidic solutions (1m hcl and 1m h2so4) were also determined. vickers hardness values for specimens, coated by ni -p at 2 and 3 hr have increased by 47 % and 32 % respectively. x-ray diffraction analysis for the coated surfaces showed two phases of ni3p and nip, presented before and after heat treatment. the sem images of the cross sectional coated specimens revealed that the thickness of the coating is 68.43 and 92.71 µm for 2 and 3 hr coating time, respectively. tafel analysis showed that the coated specimens had a lower corrosion current density compared to that for the bare specimens. the corrosion current density for the coated specimens in 1m h2so4 increased by 57 % with 2 hr and 69 % at 3 hr coating time. while, the corrosion current density for the coated specimens in 1m hcl increased by 37 % and 83 % at 2 and 3 hr coating time respectively. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction generally, deposition of electroless nickel-phosphorus has been examined since it was initially described by brenner and riddell in 1946 [1]. the electroless ni–p alloys are commonly used in different engineering applications for their typical mechanical and physical properties such as excellent wear, abrasion and corrosion resistance, ductility, soldering, lubrication, and electrical properties as well as low cost of material [2, 3]. among the electro-plating techniques, electroless deposition has more advantages due to its low equipment cost, simple in operation, and the formation ability of very thin and uniform coating on both conductive and non-conductive surfaces. [4-6]. http://qu.edu.iq/ mailto:hassanmaslab77@gmail.com https://doi.org/10.30772/qjes.v12i authors /al-qadisiyah journal for engineering sciences 13 (2019) 254–259 255 various researchers had studied the electroless plating by (ni-p) on various substrates. for example, yeh, m. s. et.al [7] studied the electroless plating of nickel-phosphorous on nickel-base alloy (inconel 718) with dimensions of 34 x 15 x 1.3 mm. the aim of this study is to promote the diffusion bonding between two overlap surfaces and to reduce the undesirable intermediate components. the results showed that the shear strength of overlap diffusion bonding before coating by nickel-phosphor was 41.5 mpa but it equal to 70.4 mpa after coating. osifuye et.al [8] investigated the effect of several parameters of the ni-p electroless plating on carbon steel aisi 1045 substrate. different parameters were considered i.e., bath concentrations, temperature, and time of deposition. the researcher employed 0.7 0.4 g/l for ni2+ while the other components stayed constant. the working temperature was variable and ranged from 70-100 °c and the plating time was 15 minutes and 35 minutes. it was noticed that the bath concentration of 0.5 -0.6 g/l at 25-35 minutes and 80 °c gave a bright uniform film. it was also noticed that the bright deposition of nickel at 25 minutes along with increasing coating time led to an increase in the amount of deposition per unit area. this was referred to the increase in wear resistance and the corrosion resistance. entesar sattar [9] studied the electroless plating of ni-p reinforced by silicon carbide (sic) on a low carbon steel substrate. the reinforcement was carried out by two different sizes of sic particles (11.2 µm and 40 nm). several tests were carried out such as optical microscope, x-ray diffraction, hardness measurement, wear, scanning electron microscopy, and corrosion test. the hardness of the substrate was 230hv while the hardness of coating that contained sic nanoparticle with 40 nm size increased by 5.2 times higher than the uncoated of base metal after the heat treatment at 400 °c for one hour. on the other hand the hardness measurement for ni-p which strengthened by particles of silicon carbide with size 11.2 µm increased by 3.8 times higher than the base metal after heat treatment at 400 °c for an hour. kari basavaraja [10] studied the electroless plating of ni-p on medium carbon steel (c-40) substrate. the researcher chose several parameters such as sodium hypophosphite, ph, and temperature. chloride nickel was the source of metal ions and sodium hypophosphite was a reducing agent. the thickness of the coating was 10-15 µm at 60 minutes and the hardness increased when the content of phosphor increased. the impact energy increased with increasing phosphor content at a temperature between 70 and 80 °c and the impact energy at 6 and 8 ph was higher than at 9 ph. martin et.al [11] studied the electroless plating of ni-p with low content of phosphor on the substrate of magnesium alloy. specimen's dimensions were (20 x 20 x 1.6 mm). the results showed uniform thin plating with 10µm thickness on the substrate at 60 min by 95.6% ni and 4.4% p concentration. on the other hand, when the time of deposition increased to 180 min the thickness of plating reached to 30 µm. the hardness values have highly increased from 410 to 610 hv. several examinations showed high resistance to corrosion by 0.1% m nacl which carried out by tafel test. the values 𝒊corr, for magnesium alloy and ni–pplating material, were 23.7 and 0.4 a/cm2, respectively. sem was conducted to know the morphology of surface after electroless plating which showed that no micro-cavities. eman et.al [12] studied the electroless plating of ni-p carbon steel specimens, the bath composition of electroless plating was nickel sulfate 15g/l, sodium hypophosphite 30g/l, lactic acid 20g/l, citric acid 20 g/l.several tests were carried out in this study, microhardness, xrd, sem, thickness of coating, and tafel analysis. the results showed that the micro-hardness increased from 160hv200 for substrate to 406 hv200 after plating. xrd analysis showed the presence of ni3p on the surface of specimens. tafel results in 3.5% nacl were 21.4 and 1.84µa/cm2 for substrate and coating specimens by ni-p respectively. 2. experimental details in this study, the metallic sheets of inconel 600 alloy with dimensions (20 x 20 x 2 mm) with middle hole (2 mm) from the top are used for ni–p coating. the chemical composition of the substrate was carried out by spectro model (spectromaxx) at general company for inspection and engineering rehabilitation-baghdad. the result of chemical composition are presented in table 1. these sheets of specimens were flattened by using sic grinding papers (180, 220, 320, 400, 600, 800, 1000, 1200, 1500, 2000, 2500 grit size). the specimens were cleaned by acetone in ultrasonic advice for 30 minutes to remove finishing compound, dust, and contaminations according to astm-b558, standard practice for preparation of nickel alloys. later, the specimens were rinsed by distilled water and dried by an electrical dryer. alkaline cleaning solution (60 % naoh + 38 % sodium phosphate+38 % sodium carbonate) was used to remove the traces of grease, oil, or any contaminations at 65-70 °c with 3v dc power supply. high activation of specimen's surface was applied to remove the thin film of oxide metal and to increase the adhesion between the surface and the plating. this process is carried out by nickel strike in electrolytic solution includes (240 g/l nicl2 and 250 ml/l hcl) with 3v dc power supply at temperature room and then the specimens were rinsed by distilled water and dried by electrical dryer. table 2 presents compositions of bath solutions and operating conditions for electroless ni– p. in ni–p bath, the sodium hypophosphite was used as a reducing agent. in addition, lactic acid and citric acid were added as a complexing agent and buffering agent respectively. the source of ion nickel was nickelsulfate. the process of coating is illustrated in figure 1. the coating thickness was measured by using sem through a cross section of coated specimens. in this study, the coating time of ni–p was (2 and 3 hrs.) respectively. an energy dispersive spectroscopy (eds) was used to analyze the coating compositions. the corrosion rates of the coating specimens in the 1m hcl and 1m h2so4 solutions were measured by tafel extrapolation. the morphology of ni–p alloy was observed by using a scanning electron microscopy (vega iii) analyzer. the hardness was measured at 25 g load and 15s hold time by machine type (hvs-1000) tester. table 1. substrate chemical composition. type c mn si ni cr fe wt.% 0.14 0.211 0.53 76.5 18.5 2.77 type s ti mo cu al wt.% 0.01 0.38 0.16 0.01 0.234 table 2. operating conditions and bath composition of ni-p [12] chemical composition concentration (g/l) nickel sulfate 15 sodium hypophosphite 30 lactic acid 20 citric acid 20 operating conditions ph 4 -6 temperature 85-90 °c magnetic stirring (rpm) 200 ± 25 256 hassan. h. masallb et al. /al-qadisiyah journal for engineering sciences 13 (2019) 254–259 figure 1. (a): sketch of electroless plating apparatus (b): the actual electroless plating 3. results and discussion 3.1. characterization of coatings 3.1.1. sem images the surface morphology of the alloys deposited by en process was shown in figure 2. the ni–p coating was successfully deposited on nickel base substrate. figure 2 (a) and (b): sem images show surface morphologies of nip plating the composition of coating at two different coating times (2 and 3 hr) and eds analysis were shown in figures 3 and 4, respectively. the deposits are mainly consisting of ni and p elements. figure 3. eds chart to coated specimen at 2 hr, coating time figure 4. eds chart to coated specimen at 3hrs. time of coating figure 5 displays the cross-section morphology of as-plated ni-p coating was checked by using sem. it was revealed that the ni-p coating thickness at 2 hrs. the time of coating is approximately 68.43µm, whereas the coating of ni-p at 3hrs time of coating has a thickness of 92.71µm. this referring that the increase in the coating time increased the deposition rate. as well as, there are no cracks or defects observed at the interface of substratecoating. this proves a good adhesion for the coatings in 2hrs. but some micro-cracks or pores have been noticed in high coating thickness which was resulted in high coating time (3hrs.). figure 5. coating thickness in sem image for coating specimens at: (a) 2 hr, and (b) 3 hrs, coating time authors /al-qadisiyah journal for engineering sciences 13 (2019) 254–259 257 3.1.2. structures of the ni-p coating figures 6 and 7 illustrate the xrd patterns for both the plated ni-p coatings and the heat-treated ni-p coatings, respectively. x-ray-diffraction analysis was used to identify all phases present in the specimens. the crystalline planes and their orientation for the phases were also analyzed. it is clear in figure 6, the presence of nip and ni5p2 in the coating layer. the major phase is nip due to more scattering of x-ray through this phase in the plane of (311) in 17 present. however, the (424) plane of ni5p2 is scattered of xray with 45 present. on the other hand, figure 7 shows the x-ray diffraction pattern for ni-p plating bath after heat treatment. it is clear that the presence of ni3p in the coating layer which considers the major phase, so it more scattering of xray through this phase in the plane (233). in most of electroless plating by ni-p, the presence of the intermetallic compound especially the (ni3p) is necessary to improve most of the mechanical properties such as corrosion resistance and hardness. figure 6: xrd pattern of electroless plating as plated figure 7: xrd pattern of electroless plating after heat treated 3.2. micro-hardness measurements micro-hardness of the ni-p coatings before and after a heat treatment were performed and compared with the inconel 600 alloy substrate, and displayed in figure 8. the micro-hardness value of the substrate was approximately 270 hv200. the electroless plating of the ni-p after heat treatment leads to an increase in the micro-hardness to 516 and 401.5 hv at 2 and 3 hrs time of coating, respectively. the increase in the hardness values is due to the formation of intermetallic compounds such as ni3p, ni5p2, and nip or any similar intermetallic compound, having a chemical formula of nixpy .all these intermetallic compounds have high resistance to penetration (hardness). figure 8: the micro-hardness of substrate, ni-p plating, before and after heat treatment at 400 °c for 1 h. 3.3. corrosion measurements 3.3.1. tafel analysis the polarization curves for electroless ni-p and the substrate in 1m hcl and 1m h2so4 solutions at temperature room are illustrated in figures 9 to 13. the parameters of electrochemical (corrosion current density (icorr) and corrosion potential (ecorr) corrosions, anodic and cathodic tafel slopes, are presented in table 2. the highest icorr occurred in bare specimens through (1m h2so4) and (1m hcl) solutions where it reached 42.235 and 27.525 μa/cm2, respectively. the current density (icorr) for coated specimens by nip has lower corrosion density than that for the bare specimens, and consequently the ni-p plating has high resistivity. the high thickness of specimens due to long coating time has lower corrosion current density (icorr) than the specimens with less time of coating. figure 9: polarization curve for bare specimen in (a): (1m hcl) (b): (1m h2so4) 258 hassan. h. masallb et al. /al-qadisiyah journal for engineering sciences 13 (2019) 254–259 figure 10: polarization curve for coated specimen by ni-p with 2hrs.time of coating in (1m h2so4) figure 11: polarization curve for coated specimen by ni-p with 2hrs. time of coating in (1m hcl) figure 12: polarization curve for coated specimen by ni-p with 3hrs. time of coating in (1m h2so4) figure 13: polarization curve for coated specimen by ni-p with 3hrs. time of coating in (1m hcl) table 3: corrosion parameters for polarization of bare and coated specimens polarization results in 1m h2so4 specimens ecorr(mv) icorr (μa) icorr (μa/mm 2) corrosion rate (mpy) bare specimen -352.8 168.94 42.235 17.201 coated specimen by ni-p for 2-hrs. -361.8 72.27 18.067 5.155 coated specimen by ni-p for 3-hrs. -252.1 52.27 13.068 3.24 polarization results in 1m hcl bare specimen -195 110.1 27.525 11.210 coated specimen by ni-p for 2-hrs. -277.7 68.83 17.207 4.910 coated specimen by ni-p for 3-hrs. -137.5 18.42 4.605 1.144 4. conclusions the electroless plating by ni-p is an effective method in the coating of metal or alloys that can provide an acceptable homogenous distribution in most metals and alloys substrates. the morphology, structure, microhardness, and corrosion resistance of the electroless ni-p plating showed better properties compared to these for the bare specimens. the structure of the as-deposited ni-p plating was amorphous, while it was crystalline for the heat-treated specimens. the coating thickness of the specimens at 2 and 3 hrs coating time has a range between (51-70) and (71-95µm) respectively. the better surface and mechanical properties were obtained in the range of thickness (51-70 µm). the thicker coating had more pores and cracks when comparison with lower thickness coating. the vickers hardness of the coated specimens at 2 hr coating time increased by 47 % when compared with the bare specimens. on the other hand the microhardness for the coated specimens at 3 hrs coating time increased by 32 % when compared with the bare specimens. tafel analysis showed a superior corrosion resistance for the coated specimens at 3 hrs coating time when compared with the bare specimens. references [1] m. palaniappa, s. k. seshadri , structural and phase transformation behaviour of electroless ni–p and ni–w–p deposits,materials science and engineering: a, 460 (2007) 638-644. [2] z.yin, f. chen, effect of nickel immersion pretreatment on the corrosion performance of electroless deposited ni–p alloys on aluminum, surface and coatings technology, 228 (2013) 34-40. [3] j. sudagar, j. lian, w. sha, electroless nickel, alloy, composite and nano coatings–a critical review, journal of alloys and compounds,. 571 (2013) 183-204. [4] r. parkinson, properties and applications of electroless nickel, nickel development institute, 37(1997) 1-33. [5] p. gadhari, p. sahoo, study of tribological properties of electroless ni-p-al2o3 composite coatings, iosr journal of mechanical and civil engineering, 1 (2014) 34-37 [6] r. n. duncan, electroless nickel: past, present and future, electroless nickel , 93(1993), conference, orlando [7] m. s. yeh, c. b., chang, t. h. chuang, diffusion bonding of a superplastic inconel 718spf superalloy by electroless nickel plating, journal of materials engineering and performance, 9 (1) (2000)51-55. [8] c. o. osifuye, a. p. i., popoola, c. a., loto, d. t. oloruntoba, effect of bath parameters on electroless ni-p and zn-p deposition on 1045 steel substrate, journal of electrochemical science, vol. 9(2014)6074-6087. authors /al-qadisiyah journal for engineering sciences 13 (2019) 254–259 259 [9] e.s. jburi, electroless ni-p coating on the medium carbon steel, msc thesis, university of babylon, iraq, 2016. [10] d. k. basavaraja, skanda, m. g., soumya, v. ramesh, experimental investigation on the effects of electroless nickel phosphorus deposition, ph and temperature with the varying coating bath parameters on impact energy by taguchi method, int j mech, aerosp, ind, mechatron manuf. eng, 11 (4) (2017) 698-704 [11] m. buchtík, p. k. jaromír, w.j. tkacz characterization of electroless ni-p coating prepared on a wrought ze10 magnesium alloy,coatings, 8 (96)(2018) 1-14. [12] e. fayyad, a.abdullah, , m. hassan, a.mohamed, c. wang, g.jarjoura, z. farhat, characterization, and application of novel ni-p-carbon nitride nanocomposites, coatings, 8 (1)(2018),. 37. article al-qadisiyah journal for engineering sciences 13 (2020) 037–045 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: drhatemhadi@yahoo.com (hatem hadi) https://doi.org/10.30772/qjes.v13i1.625 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. numerical and experimental analysis to study the effect of double triangle core on the dynamic response of sandwich structure safaa mohammed hwalah a, hatem hadi obeid a *, essam zuheir fadhel a a department of mechanical engineering, university of babylon, babil, iraq a r t i c l e i n f o article history: received 03 january 2020 received in revised form 19 february 2019 accepted 28 february 2020 keywords: corrugated cores impact load honeycomb cores transient analysis sandwich structure sandwich composite a b s t r a c t sandwich structure plates are most widely used in the automotive, aerospace and naval structures. as it gives material with low density and relatively high normal compression and shear properties. in this paper, finite element method was used with ansys apdl (16) to analyze the effect of duplicate core in sandwich steel structure on the dynamic response under the action of impact loading. also, conducted impact tests with hammer and ni devises to achieve the simulation results. the chief purpose of this work is to get a high reduction in deformation between upper and lower skins. isolate deflections of sandwich plates are compared between single and double cores of structures. the construction of the sandwich composite model consisted of two sheets layers with single triangle corrugated core and three sheets layer with double triangle corrugated core. all of configurations for both core and skin are made from the same material (steel alloy 304) and have (500mm × 500mm) length and width. the results observed that the reduction of deflection and strain are increased in double core. the comparison between experimental and numerical transient results gives good agreement with error does not exceed (13%). © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the base design of sandwich involves two thin faces that are connected by a thick cellular core. the bonding among core and two faces allows the faces and core to act as a single structure, producing a high lighter weight and strong structure [1]. showed by analytical, numerical and experimentally tests that the sandwich composite beam had a more flexural stiffness if compared with core and skin stiffness as thicknesses increase. energy of laminate indentation was less than sandwich energy but sandwich indentation consumes further energy. experimental results were in good agreement with the analytical and numerical analyses [2]. studied the dynamic response of stainless-steel square honeycomb sandwich structure, by carried out explosive experimental test in air at three values of impact load. tests were done on the sandwich structure and solid plates at constant weight. at the lowest load, it indicated that the significant front face bending and cell wall buckled gradually in the centre near to the explosion [3]. presented experimental study and numerical analysis about the compressive http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i 38 safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 nomenclature x dimensional x-coordinates subscripts y dimensional y-coordinates dic digital image correlation uy deflection in y-direction pvc baffle ω resistance fe finite element e modulus of elasticity astm fluid (pure water) greek symbols ni national instrument σy yield stress σut ultimate stress µm micrometer dynamic behaviour of four corrugated sandwich plates, these corrugated cores are (vcore, u-core, xcore and ycore). showed that the first three core type sandwich structures had better performance than the (y-core) type in the cracking behaviour and energy absorption characteristic, and when it was corrugated to (n-core) type the characteristic of crushing and energy absorption would been dramatically enhancing [4]. aimed to configure a new design of corrugated sandwich structures made from glass fibre and carbon fibre were capable of energy absorption by experimental tests. it was concluded that mixing face sheet of glass and carbon fibres (half to half) was able to provide the equivalent specific bending strength as the face sheets made fully of carbon fibre. also, indicated that the increasing the inclined angle and the thickness of core and sheet led to enhancement the strength [5]. comparison study had been achieved by using finite elements, design of experiment with response surface methods among triangular and trapezoidal corrugated sandwich structures. the results demonstrated that at constant face thickness and core high, the core cell shape did not play a largely role on the low velocity local impact response, but it's had obviously affected on the planar impact response. also, it was found that the crash resistance of triangular type was slightly better than the trapezoidal type [6]. proved that the deformation and crash level of sandwich trapezoidal core made of steel was increased with decreased impact load source distance and the thickness of front face played an important role on the deformation if compared with back face. so, a high deformation occurred in the front face and a lower deformation of back face were obtained when the increased of core height. also, observed that when the core height increased a high deformation would obtain at the front face and a lower deformation of back face [7]. investigated experimentally by using (dic) method the dynamic behaviour of sandwich with metallic face skins and (pvc) foam core under blast loading and fully clamped. it is showed that low density thick core could extended responding time and good energy absorption ability, but when using high density thin core showed its capable absorption energy when subjected to strong impulse [8]. conducted experimental tests on honeycomb sandwich structure with aluminium skins to study the effects of filler material on the failure mode. it could be found that there was an increased in the elastic strength of the sandwich structure when insert the polyurethane foam. the energy absorbed of foam filled sandwich structure was 24% more than unfilled structure [9]. from the above literature, it found that a few researchers deal with the effect of double corrugated cores on the response of sandwich structure. therefore, in this paper, it will be studying the effects of adding second core on the energy absorption and deformation mode, which gives stiffer structure and mine deflection reduction between upper and lower skins. this analysis will be done numerically by using ansys apdl (16) and experimentally impact with ni devises. 2. finite element modelling ansys (apdl16.0) software solver is used for numerical analysis in this paper, are powerful analysis tools include pre-processing (configuration of models, meshing formulation), solver and postprocessing tools in a graphical user interface. the main objectives of the numerical analysis are simulating the experimental tests that configured the sandwich structure and obtain the difference in the dynamic response was carried out experimentally. for all calculations, conditions at an initial time are set to be zero, while boundary condition is clamped from left and right edges (all degree of freedoms is taken as zero) and free from other sides. a vertical concentrated impact load is subjected at the center of upper face sheet of the models. 2.1. element types ansys offers a large packages of different element types that can be used with various problems simulation. the selection of suitable element is a significant matter in the analysis procedure. good knowledge and experience of the application are to be studied and finite element theory will support the selection of suitable type. every element type in (ansys) has a particular number and prefix which specify the type of group such as solid, link, shell, beam, and so on. each element type determines among other structural members as: 1. the degree of freedoms (dof) adjustment (that involved the structural, thermal, magnetic, electric, bricks, etc.) 2. the specification of the element coordinates, which are 2-d or 3-d domain. the analysis of the current study requires two types of elements to create the correct model: (shell281) element for sandwich structure. this element type contains (8 nodes) with (6 dof), translations and rotations in three directions. 3. configuration and material properties of models single and double triangle corrugated core were configured the sandwich structure with layers of face sheets. the sandwich model with single core has a mass of (11.2 kg) and (18.4 kg) in double core, with five-unit cell in the corrugation of the cores. the model and its dimension with single core are shown in figs. 1.a and 1.b, while the model with double cores is shown in figs. 2.a and 2. b. the thickness of skin is (1mm) and core is (2mm), while the depth is (500mm). all dimensions in (mm). the properties of materials are isotropic and have an elastic modulus (198 gpa), density (7835 kg/m3). the materials of core and skin are chosen low carbon steel with carbon percent (0.25%-0.29%). the mechanical properties such as ultimate safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 39 stress, yield stress, modulus of elasticity and the elongation were obtained from tensile test of grade a36, while poisson ratio ( was taken from standard astm a36 low carbon steel as (0.3). six samples (3 samples with 2 mm thickness and 3 others with 1 mm thickness), these samples shown in fig. 3. sheet type of astm a370 was adopted in the experimental test methods and definitions of steel products. the environmental temperature at the laboratory test was 25 c and moisture was 40%. the rate of sample displacement is (2 mm/min.). the results that obtained was the average of six specimens are shown in table 1. 4. experimental analysis test of sandwich structure plate the experimental analysis test includes transient analysis studying strain and transient time response. multi experimental tests were done to get better results. the sensors that are used in the analysis are strain gauges and accelerometers. the experimental test involves parts that illustrate in the following sections: 4.1. accelerometer sensors four piezotronics (352c03) model type accelerometers fixed in the skins of sandwich structure to sense the acceleration. the properties, number and location of these accelerometers shown in table 2. at first cleaned the surface of the interest points that the accelerometer which fixed on it and put adhesive fluid then fixed the accelerometer with carefully as shown in fig. 4. table 1. the results of tensile test. parameter symbol value unit yield stress σy 225 mpa ultimate stress σut 318 mpa modulus of elasticity e 198 gpa elongation δl 23% -- table 2. accelerometer properties and information. structure accelerometer number coordinate (m) sensitivity x y z single core 1 0.25 0.05 -0.2 10.31 2 0.25 0.05 -0.05 9.93 3 0.25 0 -0.05 10.24 4 0.25 0 -0.2 9.95 double core 1 0.25 0.1 -0.2 10.31 2 0.25 0.1 -0.05 9.93 3 0.25 0 -0.05 10.24 4 0.25 0 -0.2 9.95 4.2. strain gauge sensors the test of strain involves two strain gauges in each test, one was joined in the upper skin and other in the lower skin. the fixation method was done carefully as below. 1.refinement and cleaning the skins until the surface is very smooth and clean. 2.added strong adhesive on the place of strain gauge then put the strain gauge on the adhesive and pressed it until full adhesion. 3.wiring connection of strain gauge was done by lead solder welding as shown in fig. 5. this fixation makes the strain gauge combined with the structure, so any strain in the structure will be transferred to strain gauges. the model type of these strain gauges is (be120-20aa-x-4cm lead wire) that have resistance of 120±0.1(ω) and gauge factor was (2.00-2.20) while the number and location of these strain gauges shown in table3. table 3. properties of strain gauges. structure strain gauge number coordinate (m) x y z single core 1 0.2 0.05 -0.25 2 0.2 0 -0.25 double core 1 0.2 0.1 -0.25 2 0.2 0 -0.25 4.3. impact hammer piezotronics (086c03) impact hammer is the type that is used for the structure in the current work for exciting an impulse force for transient test. this hammer consists of quartz force sensor fixed in the end of the hammer head as shown in fig. 6. impulse testing involves striking the model with the impact hammer at the center point of upper face, and measuring the resultant motion with an accelerometers that are fixed at an interest locations [10]. 40 safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 figure 3. tensile test samples. figure 4. piezotronics accelerometers that fixed on the upper skin. figure 5. strain gauge that are fixed in the upper skin. figure 6. impact hammer instrument. figure 7. ni compact daq chassis [11]. figure 8. ni 9234 module [12]. figure 9. ni 9235 module [13]. figure 10.a. rig and vibration test of single core steel sandwich plate. figure 10.b. rig and vibration test of double core steel sandwich plate. safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 41 4.4. ni compact daq (usb data acquisition systems) the ni instruments is the main equipment used in the experimental test, one of them is the chassis 9178-daq that have an eight channel and designed for small and mixed-measurement test systems as shown in fig. 7. the 9178-daq contains four 32-bit for counter/timers compact, these counters can access through an installed, hardwaretimed digital module [11]. 4.4.1. ni 9234 and ni 9235 modules the module (9234) has four channel for receiving dynamic signal from sensors such as accelerometer (as in the test) and transfer it to chassis 9178-daq to making high-accuracy measurements. fig. 8 shows this module [12]. ni 9235 quarter-bridge strain gauge modules shown in fig. 9 is designed for higher-channel-count, dynamic strain measurement systems for ni compact daq or compact rio [13]. these devices are collected together during the tests and reading signals were extracted from the sensors by using (sound and vibration program). a real photo of the assembly of all parts of experimental test and devices shown in figs. 10.a and 10.b. 5. results the experimental tests results include the response of the sandwich structures were manufactured with single and double triangle cores and compared with corresponding simulation results. the impact load applied in the upper face sheet has value of (200 n) during (0.01 ms) for single and double core structures that was conducted by a hammer. the results obtained are the deflection in (y) direction and strain in (x) direction. the tests were achieved by using stainless steel tip hammer. 5.1. results of single core sandwich structure to obtain the deflection and strain responses, the pulse was subjected by the hammer in the test and numerically by ansys as shown in fig. 11. figure 11. magnitude of force applied. 5.1.1. results of deflection in y-direction fig. 12 shows the results of deflection that obtained from accelerometers after integrated the signal by sound and vibration software. the maximum deflection in this model occurred in the experimental results at (point 1) with (0.266 µm) and in simulation results with (0.249 µm). the error between experimental and numerical simulation was 6.83% in (point 1) and 4.33% in (point 4). 5.1.2. results of strain in in x-direction the strain results as shown in fig. 13 are obtained from the strain gauge sensors. it is clear that the maximum strain occurred in the experimental results at (point 1) is (0.32 µm/m) and in the simulation results is (0.36 µm/m). the error between experimental and numerical simulation was 11.60% in (point 1) and 8.64% in (point 2). 5.2. results of double core sandwich structure to obtain the deflection and strain responses, the same pulse was subjected by the hammer in the test and numerically by ansys. 5.2.1. results of strain in in x-direction the strain result that shown in the fig. 14 indicate that behavior is the same as in the single core structure, and there is no difference in the value of strain between single and double core in the (point 1). while the value of strain in the (point 2) that located in the lower face was reduced by percentage about (60%) compared with the single core. the maximum strain occurred in the experimental results at (point 1) is (0.34 µm/m) and in simulation results is (0.37 µm/m). the error between experimental and numerical simulation was 8.11% in (point 1) and 2.15% in (point 2). 5.2.2. results of deflection in y-direction the deflection of the double core is shown in fig. 15 indicate that the maximum deflection occurred in the experimental results at (point 1) with (0.23 µm) and in simulation results with (0.24 µm). from the response figures it is find that the double core structure differs from single core in reduced the value of the (point 4) by (93.5%). while the maximum deflection of the (point 1) does not change largely in the double core structure. this reduction is due to high moment of inertia in the double core, so can be absorbed high energy. the error between experimental and numerical simulation was 6.12% in (point 1) and 12.57% in (point 4). 5.3. maximum values and percentage of reduction it is clear from the results that the double core of sandwich structure increased the reduction in deflection and strain between upper and lower faces, because the high of the structure increased and this led to increase the moment of inertia. so, the bending stress and deflection is reduced in the double core sandwich structure. but we must not forget that the weight in the double core is more than single core by (60%), and the heavy weight structure gives high strength and more reduction, yet remains the double core is better in terms of reduction and strength. table 4 illustrate the maximum values of deflection and the percentage of reduction in single and double cores of numerical results and table 5 for experimental tests. from tables 4 and 5 the comparison between experimental and numerical results of transient load gives good agreement with maximum difference error don’t exceeded (13%). this differences are attributed to the material mechanical properties of tensile test error that used in numerical part, the noise of experimental devices error, model dimensions, bonding and contact between core and skins, boundary conditions effect and fixation of model. also, the load point in the numerical analysis is node that has very small area while in the 42 safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 experimental test the steel tip of hammer has normally more area that subjected to the force. table 4. maximum deflection and strain with reduction percentage between central points of the numerical results. no. of cores results of ansys in (mm) point 1 point 4 2/ reduction deflection single core 2.49e-7 2.31e-7 7.23% double core 2.45e-7 1.83e-8 92.53% strain single core 3.62e-7 2.20e-7 39.23% double core 3.70e-7 8.38e-8 77.35% table 5. maximum deflection and strain with reduction percentage between central points of the experimental tests. no. of cores results of experimental tests in (mm) point 1 point 4 2/ reduction deflection single core 2.66e-7 2.41e-7 9.40% double core 2.30e-7 1.60e-8 93.04% strain single core 3.20e-7 2.01e-7 37.19% double core 3.40e-7 8.20e-8 75.88% note: point 4 refer to the accelerometer no. while point 2 refer to the strain gauge no. 6. conclusions the following conclusions have been obtained:  the comparison between the single core and double core sandwich structure showed that the reduction of deflection and strain are increased in double core.  the experimental results showed that the maximum deflection occurred at the (point 1) with value of (0.266 μm) in single core and (0.230 μm) in double core at the same point. while the minimum deflection occurred at the (point 3) with value of (3.4 nm) in double core but, in the single core the value was (0.75 nm) at the (point 2).  the numerical results showed that the maximum deflection occurred at the (point 1) with value of (0.249 μm) in single core and (0.245 μm) in double core at the same point. while the minimum deflection occurred at the (point 3) with value of (3.3 nm) in double core but, in the single core the value was (0.85 nm) at the (point 2).  the experimental results showed that the maximum strain occurred at the upper point and lower strain at the lower point.  the high reduction in deflection and strain occurred in the double core sandwich structure.  the increased in percentage of reduction in deflection was from (9%) in single core to (93%) in double core, while the weight of structure was increased by 60% only.  the comparison between experimental and numerical transient results gives good agreement with error does not exceed (13%). references [1] d. gay, s.v. hoa, s. w. tsai, composite materials design and application, second edition, crc press llc, (2003). [2] m. sadighi, h. pouriayevali, m. saadati, a study of indentation energy in three points bending of sandwich beams with composite laminated faces and foam core, world academy of science, engineering and technology international journal of physical and mathematical sciences, (1) (12) (2007) 121-127. [3] k.p. dharmasena, h.n.g. wadley, z. xue, j.w. hutchinson, mechanical response of metallic honeycomb sandwich panel structures to high-intensity dynamic loading, international journal of impact engineering, (35) (2008) 1063-1074. [4] z. yan-chang, z. shi-lian, w. zi-li, crush behavior of corrugated cores sandwich panels, advanced materials research, (217-218) (2011) 1584-1589. [5] j. zhang, p. supernak, s. mueller-alander, c.h. wang, improving the bending strength and energy absorption of corrugated sandwich composite structure, materials and design, (52) (2013) 767-773. [6] s. hou, s. zhao, l. ren, x. han, q. li, crashworthiness optimization of corrugated sandwich panels, materials and design, (51) (2013) 1071-1084. [7] p. zhang, j. liu, y. cheng, h. hou, c. wang, y. li, dynamic response of metallic trapezoidal corrugated-core sandwich panels subjected to air blast loading – an experimental study, materials and design, (65) (2014) 221-230. [8] n. ye, w. zhang, d. li, w. huang, w. xie, x. huang, x. jiang, dynamic response and failure of sandwich plates with pvc foam core subjected to impulsive loading, international journal of impact engineering, (109) (2017) 121-130. [9] f.h. roudbeneh, g. liaghat, h. sabouri, h. hadavini, experimental investigation of impact loading on honeycomb sandwich panels filled with foam, international journal of crashworthiness, (17) (2018). [10] model 086c03 icp impact hammer installation and operating manual. [11] ni compact-daq usb data acquisition systems ni cdaq-9178 chassis installation and operating manual. [12] ni 9234 module installation and operating manual. [13] ni 9235 module installation and operating manual. safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 43 experimentally deflection of point (1) experimentally deflection of point (2) numerically deflection of point (1) numerically deflection of point (2) experimentally deflection of point (3) experimentally deflection of point (4) numerically deflection of point (3) numerically deflection of point (4) figure 12. experimental and numerical deflection of single core sandwich structure. 44 safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 experimentally strain of point (1) experimentally strain of point (2) numerically strain of point (1) numerically strain of point (2) figure 13. experimental and numerical strain of single core sandwich structure. experimentally strain of point (1) experimentally strain of point (2) numerically strain of point (1) numerically strain of point (2) figure 14. experimental and numerical strain of double core sandwich structure. safaa mohammed hwalah et al. /al-qadisiyah journal for engineering sciences 13 (2020) 037–045 45 experimentally deflection of point (1) experimentally deflection of point (2) numerically deflection of point (1) numerically deflection of point (2) experimentally deflection of point (3) experimentally deflection of point (4) numerically deflection of point (3) numerically deflection of point (4) figure 15. experimental and numerical deflection of double core sandwich structure. article al-qadisiyah journal for engineering sciences 15 (2022) 229–237 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: solin.k.muhammad@gmail.com (solin muhammad) https://doi.org/10.30772/qjes.v15i4.806 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. influence of intake air temperature on the performance of gasoline engines using a different type of fuel solin kamal muhammad a*, iyd eqqab maree b, and ramzi raphael ibraheem a amechanical engineering department, college of engineering, salahaddin university erbil, iraqi kurdistan, iraq baviation engineering department, college of engineering, salahaddin university erbil, iraqi kurdistan, iraq a r t i c l e i n f o article history: received 31 august 2022 received in revised form 29 october 2022 accepted 05 december 2022 keywords: si_engine engine performance intake temperature octane number gasoline fuel ricardo wave software a b s t r a c t the aim of the present study is to investigate the effect of intake air temperature on the performance of gasoline engines. various factors are taken that affect the performance of four-stroke gasoline engines. changes in air intake temperature have a significant impact on the performance of a petrol engine. consequently, an increase or decrease in the global ambient temperature will impact the performance and air quality of gasoline engines in particular. therefore, this investigation will discover the hot value of intake air temperatures that affects engine performance. this study tested two kurdistan-iraq gasoline kinds at different intake temperatures (25co, 35co, 45co, and 50co). experiments utilized a four-stroke spark ignition _engine that operated at various rates of speeds (1300, 1500, 1800, 2000, 2300, and 2500 revolutions per minute) under a half load with a 50% throttle opening. the experimental outcomes were compared with ricardo wave software simulations. the ricardo wave's theoretical outcomes were in good agreement with the experiment data it showed a near 5% to 10% variance between simulation and practical data. additionally, utilizing fuels having higher ron increases brake power owing to gasoline's greater hydrogen content and the engine's high octane fuel requirement. also, lower inlet air temperatures would be denser (more oxygen) and offer a larger mass flow during each piston cycle. hence, due to those factors, brake power was enhanced by reducing intake temp and raising ron. generally, the experiment results demonstrated that utilizing higher octane number gasoline under lower intake temperature improved engine performance which demonstrates higher power, torque, and efficiency with lower bsfc compared to utilizing higher intake temperature and lower octane gasoline. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the engine is a system that converts a fuel's chemical energy to thermal energy and then utilizes that energy to achieve mechanical work [1]. more than a century had passed since the invention of the ic_e. now it is the primary source of propulsion power for vehicles, motorcycles, locomotives, and many other machines zareei et al.[2]. currently, the s.i_engines utilized in vehicles by different manufacturers were not well suited to our climatic conditions. as a warm country, ours has a wide temperature range difference, ranging between (0 to 50) degrees celsius in different parts of the country. considering this wide range of temperatures, it's tough to conclude what temperature seems to be most suitable for engine operating http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i4.806 http://creativecommons.org/licenses/by/4.0/ 230 solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 conditions and provides us the optimum performance in terms of brake power and bsfc. mishra, p. [3]. this variation in temperature range will have an impact on fuel combustion as well since si engines release thermal energy when fuel ignites inside the engine cylinder. then, quick chemical processes take place, but the length of time it takes to combine the right amount of fuel and air relies mostly on the type of fuel utilized and how it is transported to the combustion chamber. for this purpose, the gasoline utilized in internal combustion engines must meet certain specifications. chaichan et al. [4]. a study by allawi et al.[5] that compared the performance of gasoline fuel ron 77, ron 82, ron 87, and ron 93 produced in iraqi oil refineries. four-cylinder, four-stroke, 2000cc si_engine was utilized. researchers compared experimental data with lotus engine simulation models. the les theoretical results were close to the test data. raising octane improved bte, volumetric efficiency, and brake power. improvements in gasoline fuel fineness with higher octane levels led to a decrease in bsfc measurements between ron 93 and ron 77. prihatno, a. et al. [6] investigate how octane impacts the si_engine. the investigation utilized octane-rated gasoline (92, 90, and 88). the study was using a 150cc automatic motorcycle. the findings indicate a linear rise in engine performance as gasoline octane rises, and test data for (92 and 88) indicate that brake torque, power, exhaust gas temperature, and brake thermal efficiency rose correspondingly with octane raising. also, the bsfc was dropped. ibraheem et al. [7] study how temperature impacts gasoline engine performance. four-cylinder si_engine was utilized for the engine test rig. between 10 to 50 degrees celsius. experiments found that when the intake air temperature rises, brake power drops and fuel consumption rises. and lowering ambient air temperature improved brake thermal efficiency. also, combustion and exhaust gas temperatures rise with ambient air temperature. pal, r. [8] utilize a gasoline-powered car with varied speeds and temperatures throughout the year to evaluate the impact of air temperature on vehicle performance. the vehicle's thermal efficiency and mileage improved from january to march and october, according to the study. thermal efficiency and mileage declined from october to december and march to june. march was the best month for mileage and thermal efficiency. the bsfc increased during october-december and march-june. while the bsfc dropped from june through october. in march, engine fuel consumption was the lowest. this work intends to investigate the influence of different types of fuel along different inlet temperatures on the performance of the engine through experiments and numerical simulations. with utilizing a laboratory rig fourcylinder spark-ignition engine. 2. material and method the studies were conducted utilizing two different grades of gasoline from iraq on a laboratory test bed manufactured by cussons technology model: p8610 utilizing an engine category (reliant 848cc) four-stroke fourcylinder, water-cooled petrol engine rig. table 1 displays the si_engine rig's parameters. fig. 1 depicts the engine rig utilized during this study also fig. 2 displays the schematic diagram of the engine setup. to determine the brake torque and additional engine properties, the engine was linked with a hydraulic dynamometer. to evaluate gasoline consumption and flow rate, a fuel measuring pipette and stopwatch had been used. an induction air system with a fixed slop manometer with the orifice had been used to evaluate the consumption of air. the experiments employed gasoline with two different octane ratings. in order to find out the fuel characteristics, the two types of gasoline were tested in the ministry of natural resources laboratory (mnr-lab) in erbil. the results of these tests are detailed in table 2, which provides a list of the various characteristics of gasoline that have been utilized during the experimental tests. the two types of gasoline are identified by the symbols (s) for ron-96.4 and (m) for ron-92.2 respectively. the experimental tests were done with a constant throttle opening (50%) during engine speeds ranging between 1300 rpm to 2500 rpm at half load conditions under various intake temperatures of (25co, 35 co, 45 co, and 50 co). as the tests were carried out in may, a temperature lower than 25 degrees celsius was not an option. the temperature conditions had been maintained by utilizing an air dryer heater, as demonstrated in fig. 1, and 2 it was joined to a duct that terminated at a gap of 20 cm before the intake manifold. the maximum temperature of the air heater was 65 c°, while the maximum gained hot air temperature was 50 c° due to heat losses through the duct. two thermostats were utilized to adjust the heat acquired by the electric heater while it passed through the duct. table 1. p8610 engine technical data. [9] nomenclatures: bp brake power (kw) m ron 92.2 experimental fuel bsfc brake specific fuel consumption (kg/kw.hr) m.f fuel mass flowrate (kg/s) bte brake thermal efficiency (%) n engine speed (rpm) c.v the fuel calorific value (mj/kg) ron research octane number exp experimental data s ron 96.4 experimental fuel ic_e internal combustion engine sim ricardo wave simulation data l the dynamometer load (n) si_engine spark ignition engine les lotus engine simulation t the engine torque (n.m) engine type reliant, 4-stroke, water-cooled, spark ignition engine no. of cylinder 4-in line firing order 1 – 3 – 4 – 2 (no.1 at the free end) bore 62.52 mm stroke 69.09 mm capacity 848 cm3 compression ratio 9.5:1 maximum power 30kw at 5500rpm maximum torque 63nm at 3500rpm recommended fuel premium grade gasoline, octane rating ron 98 ideal speed 900 rpm solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 231 figure 1. engine test rig table 2. gasoline usage properties 3. theoretical simulation the engine had been simulated in ricardo wave depending upon the measured geometrical characteristics and additional data from the user manual of the engine, fig. 3 demonstrates the modelled engine in ricardo wave [10]. ricardo wave software makes several assumptions for fulfilling auto-convergence criteria, and after all backend operations have been finished, the brake power and torque with other measurements from the test rig being are matched with simulation outcomes gilani, r.[11], as explained in the following sections. in the simulating conditions, two fuel files with octane numbers 97 and 93 have been created to simulate real fuel usage. the simulation fuel file (ron97) was used to simulate the real fuel usage of the fuel (s), while the simulation fuel file (ron93) was used to simulate the real fuel usage of the fuel (m). the simulation test was also done with an intake temperature of (25co, 35 co, 45 co, and 50 co) for both simulation fuel files. this has been done to find out the variance between theoretically and experimentally determined findings for two fuel types. 4. performance parameters in order to calculate the engine brake power (bp), torque (t), brake thermal efficiency (bte), brake specific fuel consumption, the following formulae should be utilized: a) brake power brake power could be defined as the quantity of work accomplished in a given period of time or the rate at which work is accomplished. 𝐵𝑃 = 2𝜋𝑁𝑇 60∗1000 (1) b) brake-specific fuel consumption the brake-specific fuel consumption (bsfc) measures how efficiently the engine utilizes the gasoline it consumes. 𝑏𝑠𝑓𝑐 = 𝑚∙𝑓 𝐵𝑃 (2) unit s m octane number -----96.40 92.20 specific gravity@15.5co -----00.76 0.737 total sulfur content wt ppm 40.00 29.00 vapor pressure at 37.8co kpa 47.00 49.00 benzene, c6h6 vol% 00.55 00.73 aromatics content vol% 29.00 27.50 olefin content vol% 08.10 01.70 saturated compound vol% 53.00 65.00 oxygen content mass% 02.07 01.30 methanol, ch3oh vol% 00.00 00.00 ethanol, c2h5oh vol% 01.70 01.60 mtbe, methyl tertiay butyl ether vol% 07.30 03.80 initial boiling point, ibp co 49.00 42.00 final boiling point, fbp co 195.0 186.0 232 solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 figure 2. engine test set up 1 figure 3. modeled engine in ricardo wave software solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 233 c) brake thermal efficiency the (bte) is a ratio that refers to the relationship between the brake power produced by the engine and the fuel energy that is delivered to the engine. 𝐵𝑇𝐸 = 𝐵𝑃 𝑚∙𝑓∗𝐶.𝑉 (3) d) torque the term "torque" refers to the capacity of the engine to transfer the generated power, and it is evaluated. a dynamometer is the instrument of choice for measuring the torque produced by an engine. 𝑇 = 𝐿 ∗ 𝑟 (4) where: r: is the torque arm = 0.254 m [9] 5. results and discussions engine performance was tested by using two types of gasoline fuel (s, m) under five different engine speeds (1300, 1500, 1800, 2000, 2300, 2500) temperatures (25, 35, 45, and 50 °c) brake power (bp (kw)) and torque (t (n.m)), brake specific fuel consumption (bsfc (kg/kw.hr)), brake thermal efficiency (bte (%)) were all determined. all findings were taken immediately from test data or computed utilizing ganesan [12]. figure 4. fuel (s) theoretical and experimental brake power vs speed this experiment data was matched with simulation outcomes, where the theoretical outcomes were in good match with the experimental outcomes. it showed a near 5% to 10% variance between simulation and practical data. this variance was due to the fact that the simulation's findings didn’t consider the engine's losses caused by utilizing an old lab engine. the following figures demonstrate the outcomes of the combined and computed data from the experiments and the simulation program: figure 5. fuel (m) theoretical and experimental brake power vs speed fig. 4, and 5 illustrate the connection between engine speed (rpm) and brake power, when utilizing different fuels and intake temperatures. increasing the octane number increases brake power by (2 % for all speed ranges) when utilizing (s) gasoline in comparison to fuel (m). however, in the simulation model, the bp was larger by (0.75%) when utilizing the ron97 model in comparison to the ron93 model at various engine speeds. the results demonstrated that the brake power dropped as the inlet air temperature rose, and the bp was reduced for fuel (s and m) by (%2 for speed below 2000 rpm and 3% for speed above 2000 rpm) for every 10degree increase in temperature. fig. 6 demonstrate a comparison of bp between (25co and 50co) degrees, the bp was decreased by (5% during speeds below 2000 rpm and 9% for speed above 2000 rpm) when fuel (s) was utilized, and reduced by (5% for speed below 2000 rpm and 8% for speed above 2000 rpm) when fuel (m) was utilized. 3.5 5.5 7.5 9.5 11.5 13.5 15.5 950 1950 2950 3950 b p (k w ) rpm fuel (s) brake power vs rpm (s)bp-exp at 25c (s)bp-exp at 35c (s)bp-exp at 45c (s)bp-exp at 50c (s) bp-sim at 25c (s)bp-sim at 35c (s)bp-sim at 45c (s)bp-sim at 50c 3.5 5.5 7.5 9.5 11.5 13.5 15.5 950 1950 2950 3950 b p ( k w ) rpm fuel (m) brake power vs rpm (m)bp-exp at 25c (m)bp-exp at 35c (m)bp-exp at 45c (m)bp-exp at 50c (m)bp-sim at 25c (m)bp-sim at 35c (m)bp-sim at 45c (m)bp-sim at 50c 234 solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 figure 6. brake power vs speed at (25co and 50co) figure 7. fuel (s) theoretical and experimental brake-specific fuel consumption vs speed as demonstrated in fig. 7 and 8. for higher octane number the bsfc was lower by (2% during engine speeds below 2000 rpm and to %4 for engine speed above 2000 rpm) for fuel (s) in comparison with fuel (m). however, in the simulation model, the bsfc for ron97 was lower than for ron95 by 0.7 percent. the bsfc incensement with increasing inlet air temperature was (1% for all speed ranges) higher for fuel (s) also the bsfc increased by (1.5 % for all speed ranges) with utilizing fuel (m) in each 10-degree temp incensement. as descript in fig. 9 the bsfc in comparison at two diff temp of (25co and 50co) was shown an increment by (4.5% for all engine speed) for fuel (m) and (%3 for all engine speed) for fuel (s). figure 8. fuel (m) theoretical and experimental brake-specific fuel consumption vs speed fig. 10, and 11 presented the connection between brake thermal efficiency and engine speed (rpm) utilizing various fuels and intake temperatures. in comparison to fuel (m) the bte increased with fuel (s) by (1% during speeds below 2000 rpm and to 3% for speeds above 2000 rpm) however in the simulation model, the bte was larger by (0.2%) when utilizing the ron97 model in comparison to the ron93 model. the bte was reduced by about (1% for all speed ranges) for fuel (s) and by (1.5% for all speed ranges) when fuel (m) was utilize with an increment for every 10 degrees in ambient air temperature. in a comparison of bte between temperatures of (25co and 50co) as displayed in fig. 12, the findings indicate that the bte became lower by (3% for all speed ranges) for fuel (s) and (5% for all speeds range) lesser while fuel (m) was utilized 3.5 5.5 7.5 9.5 11.5 13.5 15.5 950 1950 2950 3950 b p (k w ) rpm brake power vs rpm (s)bp-exp at 50c (s)bp-exp at 25c (m)bp-exp at 25c (m)bp-exp at 50c (s) bp-sim at 25c (s)bp-sim at 50c (m)bp-sim at 25c (m)bp-sim at 50c 0.27 0.29 0.31 0.33 0.35 900 1900 2900 3900 b sf c (k g /k w .h r) rpm fuel (s) brake specific fuel consumption vs rpm (s)bsfc-exp at 25c (s)bsfc-exp at 35c (s)bsfc-exp at 45c (s)bsfc-exp at 50c 0.27 0.29 0.31 0.33 0.35 900 1900 2900 3900 b sf c (k g /k w .h r) rpm fuel (m) brake specific fuel consumption vs rpm (m)bsfc-exp at 25c (m)bsfc-exp at 35c (m)bsfc-exp at 45c (m)bsfc-exp at 50c solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 235 figure 9. theoretical and experimental brake-specific fuel consumption vs speed at (25co and 50co) figure 10. fuel (s) theoretical and experimental brake thermal efficiency vs speed figure 11. fuel (m) theoretical and experimental brake thermal efficiency vs speed figure 12. theoretical and experimental brake thermal efficiency vs speed (25co and 50co) 24 26 28 30 950 1950 2950 3950 th -e ff (% ) rpm fuel (s) brake thermal efficiency vs rpm (s)bte-exp at 25c (s)bte-exp at 35c (s)bte-exp at 45c (s)bte-exp at 50c 24 26 28 30 950 1950 2950 3950 th -e ff (% ) rpm fuel (m) brake thermal efficiency vs rpm (m)bte-sim at 25c (m)bte-sim at 35c (m)bte-sim at 45c (m)bte-sim at 50c 24 26 28 30 950 1950 2950 3950 th -e ff (% ) rpm brake thermal efficiency vs rpm (s)bte-exp at 25c (s)bte-exp at 50c (m)bte-sim at 25c 0.27 0.29 0.31 0.33 0.35 900 1900 2900 3900 b sf c (k g /k w .h r) rpm brake specific fuel consumption vs rpm (m)bsfc-exp at 25c (m)bsfc-exp at 50c (m)bsfc-sim at 25c (m)bsfc-sim at 50c 236 solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 figure 13. fuel (s) theoretical and experimental torque vs speed figure 14. fuel (m) theoretical and experimental torque vs speed figure 15. theoretical and experimental torque vs speed at (25co and 50co) as demonstrated in fig. 13 and 14 the torque was improved with using fuel (s) by (2% for all engine speed) in comparison with fuel (m). also in the simulation model, the torque for ron97 model was higher than ron93 model by 0.75 percent. and for the temp effect, it was observed that the torque was reduced by (%2 during speeds below 2000 rpm and 3% for speeds above 2000 rpm) for both fuels (s and m) for each 10-degree rise in temperature. in a comparison between temp (25co and 50co) as displayed in fig. 15, the torque was lower by (5 % during speeds below 2000 rpm and to 9 % for speeds above 2000 rpm) for fuel (s) and by (5 % during speeds below 2000 rpm to 8 % for speeds above 2000 rpm) for fuel (m). 6. conclusion experimental research had been done on the engine performance while utilizing (m), and (s) gasoline types at various intake temperatures (25c°, 35c°, 45c°, and 50c°). on a realistic engine model, the study had been theoretically and empirically investigated. the experimental and simulation findings underwent analysis. the following are the main conclusions reached by this study: • the performance of gasoline engines is influenced by the octane rating and intake temperature. • ricardo wave software had been utilized to predict engine performance. the experimental values in this study were lower than the theoretical software calculations because of the losses in a gasoline engine. the variation between numerical and experimental results in all cases and conditions was around 5% to 10%. 31.5 36.5 41.5 46.5 51.5 56.5 900 1900 2900 3900 t ( n .m ) rpm fuel (s) torque vs rpm (s)t-exp at 25c (s)t-exp at 35c (s)t-exp at 45c (s)t-exp at 50c (s)t-sim at 25c (s)t-sim at 35c (s)t-sim at 45c (s)t-sim at 50c 31.5 36.5 41.5 46.5 51.5 56.5 900 1900 2900 3900 t ( n .m ) rpm fuel (m) torque vs rpm (m)t-exp at 25c (m)t-exp at 35c (m)t-exp at 45c (m)t-exp at 50c (m)t-sim at 25c (m)t-sim at 35c (m)t-sim at 45c (m)t-sim at 50c 31.5 36.5 41.5 46.5 51.5 56.5 900 1900 2900 3900 t ( n .m ) rpm torque vs rpm (m)t-exp at 25c (m)t-exp at 50c (m)t-sim at 25c (m)t-sim at 50c (s)t-exp at 25c (s)t-exp at 50c (s)t-sim at 25c (s)t-sim at 50c solin kamal muhammad, et al. /al-qadisiyah journal for engineering sciences 15 (2022) 229–237 237 • the brake power was lower with increasing inlet temperature due to the inlet temperature effect on the ignition point. while lowering the inlet air temperature raises the bp because denser (more oxygen) air allows for a greater mass flow during each piston cycle. additionally, utilizing fuels having a higher ron increases bp owing to gasoline's purity, high quality, and its greater hydrogen content. hence, due to these factors, brake power was enhanced by reducing intake temperature and raising ron. • the bsfc was strongly dependent on engine power. as mentioned in the previous point, when bp is decreased, the engine utilizes a lower amount of fuel mass per unit of power, which produces a lower amount of bsfc; in this case, the bsfc was decreased by raising ron and reducing intake temperature. according to the results, the bsfc was lower above an engine speed of 2000 rpm for both fuels, and that was due to less friction power. • with increased ron and decreased intake temperature, the brake thermal efficiency (bte) was noticeably improved. references [1] h. n. gupta, ‘fundamentals of internal combustion engines (google ebook)’. p. 676, 2012. [online]. available: http://books.google.com/books?id=s9qnrteylxsc&pgis=1 [2] j. zareei and a. h. kakaee, ‘study and the effects of ignition timing on gasoline engine performance and emissions’, european transport research review, vol. 5, no. 2, pp. 109–116, 2013. [3] p. mishra, ‘an experimental study of engine performance characteristics’, no. august, 2017. [4] m. t. chaichan, j. a. kadhum, and k. s. riza, ‘spark ignition engine performance when fueled with ng, lpg and gasolin’, environment, vol. 12, p. 59, 2016. [5] m. k. allawi, m. k. mejbel, and m. h. oudah, ‘iraqi gasoline performance at low engine speeds’, iop conference series: materials science and engineering, vol. 881, no. 1, 2020, doi: 10.1088/1757-899x/881/1/012065. [6] a. prihatno and a. hendrawan, ‘performance of spark-ignition engine at various fuel octane numbers: performance of spark-ignition engine at various fuel octane numbers’, applied research and smart technology (arstech), vol. 2, no. 1, pp. 34–40, 2021. [7] r. r. ibraheem and k. a. abdullah, ‘effect of ambient air temperature on the performance of petrol engine’, diyala journal of engineering sciences, vol. 12, no. 1, pp. 7–11, 2019. [8] r. pal, ‘effect of atmospheric temperature on the performance of a petrol car’, journal of mechanical engineering and technology (jmet), vol. 7, no. 1, 2015. [9] p. cussons, a. engine, and t. bench, ‘automotive laboratory engine test stands for automotive technicians single cylinder etb single cylinder vrc ( variable compression ratio ) etb single cylinder etb c / w variable compression engine’. [10] r. drive and v. b. township, ‘wave’, no. march, 2019. [11] r. gilani, ‘engine simulation model for a formula sae race car’, applied design, development, correlation and optimization, 2012. [12] v. ganesan, internal combustion engines. mcgraw hill education (india) pvt ltd, 2012. article al-qadisiyah journal for engineering sciences 14 (2022) 191–196 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: waleed.t.rashid@uotechnology.edu.iq (waleed t.rashid) https://doi.org/10.30772/qjes.v14i3.890 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. optimization alkaline leaching of silicon element from bauxite ore waleed t.rashid production and metallurgy engineering department, university of technology/baghdad-iraq a r t i c l e i n f o article history: received 18 november 2021 received in revised form 13 january 2022 accepted 2 february 2022 keywords: naoh concentration, particles size, stirring speed, bauxite ore, alkaline leaching a b s t r a c t the effect of alkaline leaching on the recovery of silicon element from the iraqi bauxite ore. was examined naoh concentration, particle size, and stirring speed using the program minitab 16. naoh concentration (x1) (1,2, and 4m), particle size (x2) (53,75, and 150µm), and stirring speed (x3) (250,500, and 750 rpm). the best recovery percentage was found to be (94.1097) when the variables were (x2= 53µm), (x1 = 4m), and (x3=750 rpm). the naoh concentration (x1), particle size (x2), and stirring speed (x3) have a substantial influence on the process of recovery. however, naoh concentration (x1) and particle size (x2) have a significant effect compared with the stirring speed (x3) on the recovery process. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction bauxite is a reddish clay-based rock that is most typically found in subtropical and tropical locations. silica, aluminum oxide compounds (alumina), titanium dioxide and iron oxides make up the majority of bauxite. red mud or bauxite refinery residue (brr) is a highly hazardous residue produced during the extraction of alumina from bauxite. the global production of red mud is estimated to be over 150 million tons per year a.muhanad [1]. despite the existence of recycling methods, bauxite residue is discarded as waste. it comprises raw materials for the manufacturing of silicon, iron, and aluminum. titanium oxide, hematite, and goethite are abundant in iraqi bauxite. titanium oxide and iron should be eliminated to meet the industrial criteria hanny et al. [2]. in iraq, the only identified bauxite resources are the north hussainiyat karst bauxite deposits in the western desert. they have been discovered by the iraqi geological survey in the year 1990 ranging from a few meters to 35 meters thick in ubaid formation (early lower jurassic) fossil karsts of varying sizes, coupled with kaolinite, bauxite kaolinite, quartz sandstone, and flintclay. the thickness of a few highly bauxite profiles can reach 100 meters their et al. [3]. the sequence of treatments is determined by the raw mineral, chemicals. those processes primarily center on extraction, which involves separating the impurities that come with the metal and other mechanical components. shredding processes, wet and dry screening, magnetic separation, gravity separation approaches, electrostatic separation float, and other physical techniques that take use of variations in the chemical and physical surface qualities of the metal and its impurities may be adequate choices. the effectiveness of such operations is determined in large part by the selection of acceptable working conditions for each approach [1] as well as the metal ratio in the raw materials and the technique or procedures used for separating and concentrating them. the aim of this study is to use a hydrometallurgical process for recovering silicon from iraqi bauxite ore. the recovered silicon http://qu.edu.iq/ mailto:waleed.t.rashid@uotechnology.edu.iq%20%20(waleed https://doi.org/10.30772/qjes.v14i3.890 https://doi.org/10.30772/qjes.v14i3.890 http://creativecommons.org/licenses/by/4.0/ 192 waleed t.rashid/al-qadisiyah journal for engineering sciences 14 (2022) 191–196 element is considered as a valuable material for technological and industrial applications. 2. experimental work 2.1. atomic absorption spectroscopy the dissolved si element in the solution of leaching process, was determined by the atomic absorption spectroscopy type (nova aa 350), at the laboratories of ibn-sina state company . 2.2. materials and method the bauxite ore samples were provided by the iraqi geological survey, which came from the al-hussain at area in western iraq's anbar province. the sio2 concentration was (14.2) wt%. the chemical composition related to bauxite ore is shown in table 1. the xrf analysis of bauxite ore done in the iraqi-germany laboratory, college of geology at the university of baghdad. the chemical analysis was achieved by x-ray fluorescence (shimadzu 1800, xrf). a 1 kg bauxite ore sample was comminuted by laboratory ball mill and jaw crusher, they were done in the mineral processing laboratory of the department of production engineering and metallurgy, and the bauxite powder was split into equal samples using a laboratory jones riffles splitter for chemical composition and leaching experiment testing. table 1. chemical composition of iraqi bauxite ore. 2.3. leaching process the leaching of element from bauxite ore by (naoh) was performed in a 250 ml, necked round bottom reaction glass vessel. the reaction vessel was heated using the magnetic stirrer hot plate. the stirring of mixture was done by the magnetic stirring coated by teflon. the leaching efficiency (l%) can be calculated using the following equation alghanmi et al. [4]: 𝐿% = (c1 × v) /(co × w) × 100 (1) where: l % represents the leaching efficiency’s percent, and 𝐶1 represents the concentration of a metal in solution in g/l. 𝐶o represents the concentration of a metal in solid in wt% and v represents the volume of leaching solution in l. w represents the weight of solid sample in gm. 3. design of experiments the elements recovery from bauxite ore is significantly influenced by the process factors. table 2 illustrates the independent controllable process factors that have been found to have a substantial impact on leaching. the goal of leaching manipulations is to investigate the effects of specific parameters (leaching agent concentration (x1), particle size (x2), and speed string (x3)( for determining their optimal values for maximum si dissolution from bauxite ore, while keeping other variables constant, such as temperature (25 celsius) and liquid to solid ratio (2:1). table 2 lists all of the factors which the present research. also, the leaching procedure and responses are utilized to determine the value of silicon elements from the iraqi bauxite ore. table 3 shows the experimental outcomes as well as the experimental strategy (matrix). table 2. the factors and their levels employed in the experiments furthermore, the response surface 'y' for k factors is represented via the 2nd-order polynomial regression equation marzouk et al. [5]. 𝑌 = 𝑏𝑜 + ∑ 𝑏𝑖 𝑋𝑖 𝑘 𝑖=1 + ∑ 𝑏𝑖𝑖 𝑋𝑖 2 𝑘 𝑖=1 + ∑ 𝑏𝑖𝑗 𝑋𝑖 𝑋𝑗 𝑘 𝑖=1 (2) where: 𝑏𝑜 = constant, 𝑏𝑖 = linear term coefficient, 𝑏𝑖𝑖 = quadratic term coefficients, 𝑏𝑖𝑗 = interaction term coefficient in which 𝑏𝑖 , 𝑏𝑖𝑖 , and 𝑏𝑖𝑗 are the coefficients that rely on the main and interaction effects of the factors, and b0 represents the average of responses. also, the coefficients were estimated with the minitab 16 program. after finding the coefficients, the mathematical model was created. at a 95% confidence level, all of the coefficients were evaluated for significance. table 3. experimental design matrix and observed values of the recovery no x1 x2 x3 c p s. s y=recovery si element % 1 -1 -1 0 1 53 500 83.4 2 1 -1 0 4 53 500 93.8 3 -1 1 0 1 150 500 83 4 1 1 0 4 150 500 89.7 5 -1 0 -1 1 75 250 82.7 6 1 0 -1 4 75 250 85.6 7 -1 0 1 1 75 750 84.1 8 1 0 1 4 75 750 90.1 9 0 -1 -1 2 53 250 86.2 10 0 1 -1 2 150 250 84 11 0 -1 1 2 53 750 87.6 12 0 1 1 2 150 750 86.4 composition al2o3 sio2 fe2o3 zr2o3 content wt. % 6.52 14.2 2.169 0.3 composition p2o5 tio2 cao content wt. % 0.332 0.452 0.161 factors notations levels -1 0 +1 naoh concentration (x1) c (m) 1 2 4 particle size (x2) p (µm) 53 75 150 speed string (x3) s.s (rpm) 250 500 750 waleed t.rashid /al-qadisiyah journal for engineering sciences 14 (2022) 191–196 193 13 0 0 0 2 75 500 85.2 14 0 0 0 2 75 500 85.2 15 0 0 0 2 75 500 85 4. results and discussion 4.1. test of significance the coefficients of the regressed model have been tested for their significance with a use of rsm (i.e., response surface methodology) in minitab program, as can be seen in table 4. utilizing the level of significance (b = 0,050), coefficients that have p-values > (b = 0.050) are not significant (b23, b22, and b33), and will be removed from the model., the left coefficients (bl, b2, b3, b11, b12 and bl3). as a result, the derived mathematical model for si recovery might be written as a following: 𝑌 = 71.214 + 1.885 𝑋1 − 0.2736 𝑋2 + 0.0089 𝑋3 + 0.021 𝑋11 + 0.0772 𝑋12 + 0.0022 𝑋13 (3) in which the variables (x1), (x2) and (x3) represent the naoh concentration, particles size, and stirring speed, respectively, and (y) represents the recovery si element. it is noted from equation (3), the naoh concentration has the greatest influence on the recovery, whatever the case, the naoh concentration and particles size have the best influence on the recovery, while the effects of stirring speeds (x3) are less in comparison to (x1, and x2). table 4. response surface regression: y versus x1, x2and x3 term coef se coef t p constant 71.2145 08.9337 10.2100 00.0000 c 01.8849 02.9056 00.6490 00.0050 p -00.2736 00.1327 -02.0620 00.0040 s.s 00.0089 00.0171 00.5230 00.0030 c*c 00.0208 00.4715 -00.0440 00.0040 p*p 00.0013 00.0006 02.1570 00.0090 s.s*s.s -00.0000 00.0001 -00.6930 00.5190 c*p 00.0772 00.0111 -00.6540 00.0020 c*s.s 00.0022 00.0023 00.9630 00.0050 p*s.s 00.0000 00.0001 00.1920 00.0070 4.2. analysis of variance (anova): the anova test has been utilized in order to identify the important design parameters that influence on the recovery of si element. table 5 shows that the (p-value) is not more than 5% based on the significant level (0.050) and applying the regression model's test (f-test), indicating that the model of regression is significant [6]. this outcome is acceptable. r-sq adjusted equals 70.22%, indicating the independent variables (x1, and x2). the rest is a result of other factors like the random error and explains that (70.22%) of the variables ocuur in the variable (y). in the case when the determination coefficient is near to one of the best, the findings are likely to be satisfactory. 4.3. the main effect plot of recovery si element figure 1 exhibits the influence of particle size, naoh concentration, and stirring speed on the recovery of si from bauxite for values between (+1, -1). it can be seen that there is a gradual increase in the recovery with the increase in naoh concentration, which is due to the excellent attack of sodium hydroxide on bauxite ore, resulting in the decomposition and disintegration of elements [1]. table 5. analysis of variance for y source df seq ss adj ms f-value p-value regression 9 131.185 14.5761 4.67 0.003 residual error 5 15.615 3.1231 total 14 146.8 s=1.76722 r-sq=89.36 r-sq(adj)=70.22 from figure 1, it can be seen that the recovery increases as the particles size is decreasing, and the highest percentage of (l %) obtained is at 53 μm. the reason for increasing the (l%) with the decrease in particle size is due to the increasing of the surface area exposed to reaction with naoh, the rate of transmission of materials is large and thus increases the reaction rate zheng et al. [7]. fig. 1 specifies that the leaching of the si element increases gradually. however, when increasing the speed for more than 500 rpm, the leaching efficiency starts to decrease. during the leaching process, the heterogeneous reaction occurs at the interface, which is between the phases of solid and liquid, at the boundary between the two phases, and the layer of diffusion is created. with regard to solid in the aqueous phase, such layer includes a stationary aqueous layer, the diffusion layer might be thinned through excessive stirring, yet not totally removed, in which the leaching effectively elevated with the increase in stirring speed. increasing the stirring speed causes an increase in the leaching efficiency because of the suspension of mineral particles and a decrease in the thickness of the mass transfer boundary layer on the particle surface shabani et al. [8]. while, the noted lower efficiency of leaching with a higher stirring rate of more than 500 rpm might be ascribed to the violent agitations causing particles to adhere to the flask’s inner wall. such an approach decreased the efficiency of leaching wang et al. [9]. 4.4 normal probability plots the normal probability plot of the residuals is shown in fig. 2. the residuals of data are essentially distributed normally since the total points make an approximately straight line, as shown by the normal probability plots created with the computer software minitab. the distribution and spread of residual are shown in fig. 3 which happens in a random form on the two sides of a line representing the value of 0 (a line separating the negative and positive residuals). this is because the error of result is a random error, which cannot be monitored in a specific form, as it is 194 waleed t.rashid/al-qadisiyah journal for engineering sciences 14 (2022) 191–196 not decreasing or increasing or only exists on one side. thus, such residuals do not have a constant variance figure 1. main effect plot of residuals of recovery si element figure 2. normal probability plot of residuals of recovery si element figure 3. plot of residuals vs value of recovery si element 4.4. optimization of recovery of si the optimization chart for the recovery of si at various values for three factors (x1, x2, and x3) is shown in fig. 4. the best setting of each one of the parameters is displayed in the middle of the top row, whereas optimization of the result has been displayed in the left column. each factors behavior curve is depicted below. as illustrated, an optimal run at a concentration of naoh (4 m), stirring speed (750 rpm) and a particle size of bauxite ore (53µ m) might lead to the silicon element recovery (94.1097%). the values of particle size (x2), sodium hydroxide concentration (x1), and stirring speed (x3) produced with the use of programs were applied, resulting in a silicon element recovery of (95.88%), which is substantially identical to that achieved by the program. 4.5. response surface analysis fig. 5 a, b, and c shows three-dimensional plots and figure 5 d, e, and f shows the contour plots for the effect of factors (x1, x2, and x3) on the response y (recovery si element from bauxite ore). where, it was noted that there is a sharp increase in the recovery with an increase in the concentration of sodium hydroxide (x1) compared with other factors(x1) and (x2). as for the particles size (x2) and the stirring speed (x3), they have almost the same effect, where the increased recovery is clear with the decrease in the volume of the raw particles and the increase effect than the combined effect of sodium hydroxide(x13) and the stirring speed or the combined effect of the stirring speed with the size of the particles(x23).in the stirring speed. on the other hand, it was observed that the combined effect of sodium hydroxide and the size of the particles(x12) have a greater effect. figure 4. optimization chart for maximum of recovery si element. waleed t.rashid /al-qadisiyah journal for engineering sciences 14 (2022) 191–196 195 figure 5. three-dimensions and contour plots of recovery si. b c d e 196 waleed t.rashid/al-qadisiyah journal for engineering sciences 14 (2022) 191–196 5. conclusions 1. regression models might be represented by eq. 3, which x1 has a considerable impact on the recovery of si element. it must be noted that x1 has the greatest impact in comparison to the influence of x2 and x3. 2. the combined influences of naoh and the size of the particles (x12) have greater effect as a compared with the combination effect of sodium hydroxide (x13) and the stirring speed or the combined effect of the stirring speed with the size of the particles (x23). 3. the increase in the concentration of naoh (x1) and decrease in particles size of bauxite (x2) and increase in the stirring speed(x3) caused the increased improvement of the recovery of si. 4. the optimal recovery of si element has been obtained at naoh concentration (x1) 4m, particles size (x2) 53um, and stirring speed (x3) 500 rpm, in which the recovery of silicon element (93.8 %). 5. it is possible to obtain an increase in the recovery of the silicon element (94.1097 %) when using the variables, naoh concentration (x1) 4m, particles size (x2) 53um, and stirring speed (x3) 750 rpm. refernces [1] muhanad, “ extraction of zirconium oxide from iraqi bauxite ore”, degree of master of science, department of production engineering and metallurgy /university of technology,2020. [2] s. hanny, k. leiv and s.jafar, “iron separation from bauxite thought smelting reduction process” mineral, metals and material science,no.2,vol. 7491,2017. [3] m. thair, s. khaldoun and m. mazin, “ karst bauxite deposits of north hussainiyat area, western desert, iraq: an overview”, iraqi bulletin of geology and mining, no.8,pp. 125 – 146, 2019. [4] s. alghanmi, f. amani, a. tahani, g. basma, and m. abdel salam. “acid leaching of heavy metals from contaminated soil collected from jeddah, saudi arabia: kinetic and thermodynamics studies.” international soil and water conservation research vol.3, no. 3, pp.196-208,2015. [5] i. marzouk, l. dammak, l. chaabane, b. hamrouni“optimization of chromium (vi) removal by donnan dialysis” american journal of analytical chemistry, vol.4, no.6, pp.306-313,2013. [6] s. venkatprasat, r. subramaian, n. radhika, b. anandavel, l. arun and n. praveen, “influence of parameters on the dry sliding wear behavior of aluminum \flyash graphite hybrid metal matrix composites”, european journal of scientific research, vol.53, no.2, pp.280-290, 2011. [7] r. zheng, l. mei, g. kai, z. dongliang, h. lan, x. wei, and l. xingyu, “effect of particle size refinement on the leaching behavior of mixed rare-earth concentrate using hydrochloric acid”, american chemical society, no. 4, pp.9813−9822, june2019. [8] m.a. shabani, m. irannajad, and a.r. azadmehr,” investigation on leaching of malachite by citric acid”, international journal of minerals, metallurgy and materials vol. 19, no. 9, pp782-786,2012. [9] y. wang, s. jin, l. yan, and s. haifeng, “hydrometallurgical process and kinetics of leaching manganese from semi-oxidized manganese ores with sucrose”, minerals,vol. 7,no.27, 2017. article al-qadisiyah journal for engineering sciences 14 (2022) 178–183 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mech.post01@qu.edu.iq (maryam alaa abdulhussein) https://doi.org/10.30772/qjes.v14i3.775 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. an experimental study of the thermal behavior of bricks integrated with pcm-capsules in building walls maryam alaa abdulhussein*, alaa liaq hashem department of mechanical engineering, college of engineering, university of al-qadisiyah, ad-diwaniyah, iraq. a r t i c l e i n f o article history: received 19 october 2021 received in revised form 14 november 2021 accepted 21 november 2021 keywords: phase change material energy storage building efficincy insulation paraffin a b s t r a c t buildings are the major energy users and by 2035, they will be the fourth largest source of greenhouse gas emissions. phase change materials (pcms) are applied to shift the peak-load to the off-peak-load, positively effecting the efficiency of the building. in this paper, an experimental embedding of pcm (paraffin) with bricks in conventional wall layers is carried out. the effect of this on the thermal diffusion of the inner surface of the wall is studied. capsules are manufactured to fit the size of the holes inside the bricks and they are filled with paraffin (147 kj/kg latent heat, 38oc solidified and 43oc liquidised) and closed in a way that prevents leakage. each brick contained two rows of holes (5 holes per row). capsules are placed in the holes at a rate of 5 capsules per brick and 10 capsules per brick. three wall samples are experimentally tested: traditional wall, wall containing 5 capsules/brick and a wall containing 10 capsules/brick. the indoor test with light intensity has been fixed on 900 w/m2 during the heating period for 4 hours and the remaining period of cooling. the temperature measured and recorded for the internal, external surfaces and the middle of the wall using k-type thermocouples and datalogger. the results indicated that, bricks wall with 10 pcmcapsules per brick reduced the heat flux by 34.17% compared with traditional wall sample, and energy stored 50% more than a wall with 5pcm-capsules per brick. the lowest temperature of the internal wall surface of sample 10 capsules per brick is recorded compared to the reference wall where the difference is more than 3°c. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction by 2035, buildings will be the leading consumers of energy and a significant source of greenhouse gas emissions [1, 2]. developing new techniques to store renewable energy and further exploring heating strategies and passive cooling is one primary subject in sustainable building research. phase change materials or pcms are applied to shift the peak-load to the off-peak-load, positively effecting the efficiency of the building. various studies have shown that integrating thermal mass in building structures may save 5% to 30% on cooling and heating energy in residential buildings [1, 3]. phase change materials can be classified into three categories: organic pcm, inorganic pcm, and metal and metal alloy pcm fleischer [4]. paraffin and fatty acid are types of organic pcm. the phase change range of the paraffin is often between 35 oc and 70 oc, convenient to the electronic application that often has a maximum junction temperature of 85 oc. while, fatty acids are more suitable for residential application because it has lower melting points paraffin. in addition, a fatty acid is commonly studied pcms for reducing hvac costs [4]. the main elements in the formation of the inorganic pcms types are salt and http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ maryam alaa abdulhussein et al. /al-qadisiyah journal for engineering sciences 14 (2022) 178–183 179 salt hydrates. the nature of phase changing material mechanism in which the material melt and freeze at operation time makes integrating phasechanging material into construction components a significant difficulty. as a result, whether pcm packages are built-in micro or macro encapsulation is determined by the integration needs [5-7]. tiago silva et al. [8] studied the integrating pcm with building materials by experimental tests and numerical simulation. the study tested the impact of adding pcm to a standard portuguese brick in an experiment. they constructed a macro capsule made of steed and filled it with pcm, and then he added the capsule to the hollows in the brick at adequate dimensions. concrete mortar was used as an added ingredient to build the wall. the pcm used was paraffin rt18 with melting temperature of 18°c. the numerical results were compared the experimental tests results in order to validated it. they achieved a reduction in temperature from 10 to 5°c, plus diminishing the fluctuation in the indoor space temperature, and achieved a three hours’ time-delay. xing jin et al. [9] examined the pcm's thermal performance and predicted where it should be placed in the system. the "pcm thermal shield (pcmtss)" configuration of encapsulating pcm was utilized in this research. pcmts involves sandwiching pcm between two layers of covering aluminum foil after encapsulating the pcm in fat polyethylene bubbles. the size of the aluminum foil was (60.2 cm x 40.6 cm). at various distances from the inner surface of the wallboard, the thermal heat behavior of the walls with phase change materials was observed. the boundary layer was the furthest away from the heating source in the simulator. using a high transient wall modeling program, the optimum position for the pcm layer, according to the findings, is 1/5 l of the exposed inner surface furthest from the heat source. the maximal heat flow attenuation at this site was 41%, with 2 hours for load shifting. it is worth mentioning that the pcm that was used in this experiment was a proprietary hydrated salt. with a phase transition temperature range of 24oc-34°c, the latent heat was 140 kj/kg. osama, et al. [10] built two walls, one wall had been treated with paraffin wax, and the other was a traditional iraqi wall. the treated wall thickness dimension was of 0.5 cm external layer of concrete, followed by a 2cm layer of (80% cement mixed with 20% paraffin wax). the next layer was 24cm of typical brick and 2cm of gypsum as internal layer. the second traditional wall had an external layer of 2.5cm thickness of concrete, followed by a 24cm layer of brick and the internal layer is 2 cm of gypsum. the two walls models had contained eleven thermocouples ktype, which were implanted through their centerline from the external surface to the internal surface. the paraffin capsules had been wrapped in aluminum foil with a thickness of (0.06mm), and then it was covered by an adhesive coating to prevent any leakages. a capsule dimension was 0.8cm x 0.8cm. the two wall models had a dimension of (300mm x 300mm) and had been insulated from four sides by a glass wool layer, so the energy exchange was kept in one direction, and the heat loss was reduced. the researcher had achieved a difference of (1.6°c) between the treated and non-treated walls. the heat flow toward the interior surface was reduced when the wall was coated with phase change material because of its heat storage ability. the focal point of this paper is integrating macro capsules filled with paraffin into the bricks of the traditional wall, and study the thermal behavior of pcm under constant radiation. 2. description of the experimental system 2.1. phase change material thermodynamically the phase is defined as the homogeneous state of the materials, which is the chemical arrangement and physical state of matter. the phase of a substance changes (solidify or melt) at a specific temperature and pressure [11]. phase change material (pcm) is the material that undergoes a phase transformation, where pcms may absorb and release heat during phase transitions (mostly from the solid to the liquid state and vice versa) at a reasonably constant temperature as shown in fig. 1 [12]. phase change materials (or latent heat materials) have the ability to store and release large quantities of heat [4, 11]. paraffin wax which refers to as rt-42 was used in this study as a latent heat material. table 1. thermos-physical properties of building materials used [12]. nomenclature cp specific heat (j/ kg. k) greek symbols pcm phase change material ρ density (kg/m³) k thermal conductivity (w/ m.k) 𝚲 latent heat of fusion (kj/kg) e energy (kj) 𝝓 porosity t temperature (°c) subscripts m mass (kg) rw reference wall (traditional wall) q heat flux (w) se external surface δt temperature difference (°c) si internal surface b brick k(w/m.k) c(j/kg.k) ρ(kg/m³) concrete 0.99 2040 2020 brick 0.66 1060 1880 paraffin 0.2 2000 899 (solid) 760 (liquid) 180 maryam alaa abdulhussein et al. /al-qadisiyah journal for engineering sciences 14 (2022) 178–183 the liquid temperature of the paraffin is 43ºc, and the temperature at which the material solidifies is 38°c. the latent heat of the material is 147 kj/kg. paraffin wax has a thermal conductivity equals to 0.2 w/m.k [6]. the term (𝛌)referring to latent heat of fusion, which is variable for each material, is used in equation (1) to determine the energy storage potential in a given quantity of mass m.[4]. 𝐸𝑠𝑡𝑜𝑟𝑒𝑑 = 𝑚𝜆 (kj) (1) 2.2. experiment set up the experiments took place at al-qadisiyah university, college of engineering. a small room was built as shown in fig. 2. the room was built using a cube-shaped iron frame with dimensions of (110 x 110 x 100 cm) and was insulated using a sandwiched panel with 5 cm thickness. on one side of the room, a 60x60 cm void was left for a wooden frame with 5 cm thickness to be fitted. a total of three samples was built in this experiment. each wall was built at a time inside the wooden frame for the experiment to be conducted separately on each sample. the walls of the experiments had a dimension of (50 x 50 x 28cm). the first wall sample was traditional wall made of 2 cm layer of concrete followed by 24 cm layer of perforated brick followed by 2 cm layer of concrete. in order to make a suitable packaging for the paraffin used, a cylindrical capsule was made. for the capsules to fit in the perforated brick holes, the appropriate dimension would be 8 cm high and 2.5 cm diameter. galvanized iron was used to make the upper, perforated cover and the lower base of the cylinder, and the regular iron to make the body of the cylinder. the iron used was 0.04 cm thick. a needle hole was left at one of the bases of each capsule for paraffin filling through. each capsule carried 30 g of paraffin wax as shown in fig. 3. the second wall sample was referred to as c1 and in this sample 50 capsules filled with paraffin was used. the capsules were installed in the first row of the brick’s holes. the third wall sample was referred to as c2 and in this sample 100 capsules were used, and installed in the first and second row of the brick layer as shown in fig. 4. four projectors lamps of 1000 watt power were used as a radiation source. the light sources were installed on an iron frame and were situated 50cm away from the wall sample external surface. the radiation intensity used in this experiment was controlled to be a fixed value equal to 900 w/m² and it radiates vertically on the external surface of the wall. table 1 shows the building material properties. the device used to record temperatures overtime was at45xx with highperformance arm microprocessor control as shown in fig. 2. it calculates the temperature data instantaneously during the experiments and stored it into a connected pc. the thermocouple distribution is shown in fig. 5. figure 2. the experimental room with the heat source. figure 3. injecting melting paraffin wax in capsule. figure 4. perforated brick filled with pcm capsule. figure 1. the phase change material. maryam alaa abdulhussein et al. /al-qadisiyah journal for engineering sciences 14 (2022) 178–183 181 2.3. theoretical background conduction occurs when thermal transmits through the solid media or quiescent fluid. fourier law demonstrates the heat flow when heat transfer through conduction. the heat moves per unit length in the solid dt dx⁄ [13].when the wall has more than one material, and each material has different thermal conductivity (k), the temperature gradient happens at each layer [14]. 𝑄 = −𝑘𝐴 𝑑𝑇 𝑑𝑥 (w) (2) moreover, the multilayer wall is called a composite wall, and the heat flow calculation is slightly different. the overall heat transfer term is used when more than one thermal resistance combines conduction and convection exists [14]. 𝑈 = 1 𝑅 (w/m².k) (3) the term (ρ) refers to the density in (kg/m³). tliquid (°c) is the temperature at which the paraffin melt and tsolid (°c) is the temperature at which paraffin solidifies [15]. here, ∆t = tliquid − tsolid, which is equal 5 in case of paraffin wax rt-42 [6]. (𝜌𝐶)𝑃𝐶𝑀 = { (𝜌𝐶)𝑠𝑜𝑙𝑖𝑑 𝑇 < 𝑇𝑠𝑜𝑙𝑖𝑑 (𝜌𝐶)𝑠𝑜𝑙𝑖𝑑+(𝜌𝐶)𝑙𝑖𝑞𝑢𝑖𝑑 2 + 𝜌𝑠𝑜𝑙𝑖𝑑+𝜌𝑙𝑖𝑞𝑢𝑖𝑑 2 ( 𝜆 𝛥𝑇 ) 𝑇𝑠𝑜𝑙𝑖𝑑 ≤ 𝑇 ≤ 𝑇𝑙𝑖𝑞𝑢𝑖𝑑 (𝜌𝐶)𝑙𝑖𝑞𝑢𝑖𝑑 𝑇 > 𝑇𝑙𝑖𝑞𝑢𝑖𝑑 } (4) the porous media concept can be applied to the bricks used in the experiment. the experimental wall was made of three layers as shown in fig. 6. two layers of concrete sandwiched the third layer of perforated bricks. perforated bricks are porous media of some sort, containing voids of cylinder holes usually filled with air. as will come later, those holes were filled with cylindrical capsules made of iron of small thickness and filled with paraffin wax. the thermal conductivity of the perforated brick filled with pcm capsule can be calculated from the equation (5) [16]: 𝑘𝑃𝐶𝑀 𝑐𝑎𝑝𝑠𝑢𝑙𝑒 = (1 − 𝜑)𝑘𝑏 + 𝜑𝑘𝑃𝐶𝑀 (5) for the c1 wall where pcm capsules filled only one row of the brick holes, half the volume of the brick was taken into account during calculation, while in the c2 wall, where all ten holes of the brick were filled with pcm capsules, the whole volume of brick was included. as shown in figs. 6(b) and 6(c). figure 5. schematic of the experimental and the distribution of the sensor. (a) (b) (c) figure 6. a) traditional wall, b) c1-wall, and c) c2wall. 182 maryam alaa abdulhussein et al. /al-qadisiyah journal for engineering sciences 14 (2022) 178–183 when using pcm as part of the wall layers, equation (6) demonstrates the amount of flux that move through the wall. where 𝑄𝑠𝑡𝑜𝑟𝑑 is equal to the heat stored in the phase change material. 𝑄𝑐𝑜𝑛𝑑 = 𝑄𝑓𝑙𝑢𝑥 − 𝑄𝑠𝑡𝑜𝑟𝑒𝑑 (6) 3. results and discussions fig. 7 shows the temperature change of the external wall surface with time under the radiation intensity of 900 w/m2. after the radiation source is turned on, the temperature of the external surface rises sensibly and significantly in all cases. the temperature of the traditional wall continues to rise linearly during the first 30 minutes, reaching 54.02°c. the increase continues but less gradually and slows down with the end of the heating period after 4 hours where the temperature reaches its maximum value of 73.8°c. in all the other cases, the same scenario is observed above where the temperature starts to increase sensibly but at a slower rate compared to the case of a traditional wall. as the heating process continues, the temperature begins to increase at a gradual rate until it reaches its highest values at the end of heating to 63.02oc and 55.42°c at c1 and c2 respectively. the maximum temperature in all cases was less than the traditional wall temperature due to the added element of pcm. according to fourier equation, heat flux is generated in the wall layers due to the absorbed radiation at external layer, which is directly proportional to the temperature difference, the thermal conductivity of the wall layers, and the wall area, and inversely with the thickness of the wall. it can be noticed from fig. 8 that the temperature curve increases slowly for the first hour because of the time lag. the time lag happens due to the multiple resistance layers of the wall that suppress the travel of heat toward the internal surface lower temperature. after four hours of continuous heating the internal surface temperature of the rw, c1, and c2 walls were at 23.1°c, 20.5°c, and 20.76 °c respectively. the temperature continues rising even after the heat source was turned off, as shown in the fig. 8 because of the stored heat in the wall layers and the time lag. after two hours of the cooling period, the internal surface temperature reached its maximum, the rw, c1, and c2 walls' temperature were equal to 25.96°c, 23.42°c and 22.8°c respectively. the table 2 below shows the heat flux calculation which was generated in the wall layers at the end of the heating period. the highest heat flux was at the traditional wall and was equal to 33.8 w. while the minimum heat flux was at c2 and was equal to 21.7 w, which is the optimum case. table 2: heat flux at maximum external surface temperature for radiation: 900 w/m² 𝑻𝒔𝒆(°𝑪) 𝑻𝒔𝒊(°𝑪) ∆𝑻(°𝑪) 𝑸(𝑾) rw 73.8 23.1 50.7 33.8 c1 63.02 20.5 42.52 26.6 c2 55.42 20.76 34.66 21.7 the paraffin temperature curve of the experiments conducted for c1 and c2 as shown in fig. 9. the c1-r1 and c2-r1 curves represent the pcm temperature in the first row of c1 and the first row of c2. while c2-r2 10 20 30 40 50 60 70 80 t (º c ) time rw c1 c2 figure 7. comparing the external surface temperatures ( 𝐓𝐬𝐞) for walls samples with the reference sample. 10 12 14 16 18 20 22 24 26 28 t (º c ) time rw c1 c2 figure 8. comparison of interior wall surface temperatures 𝐓𝐬𝐢 variation for walls samples with the reference wall sample. 0 10 20 30 40 50 60 70 t (º c ) time c2-r1 c1-r1 c2-r2 figure 9. comparison of the temperature of the first row of paraffin in c1 and c2, and the second row of c2. phase change rang maryam alaa abdulhussein et al. /al-qadisiyah journal for engineering sciences 14 (2022) 178–183 183 represent the pcm temperature in the second row of c2. the initial temperature of the thermocouples attached to the capsule was reading 17.5oc, 19.1°c and 19.9oc for c1-r1, c2-r1 and c2-r2 respectively. it took more than one hour for the pcm temperature to reach 38 °c in c1r1, 38.1°c in c2-r1, and 37.3°c in c2-r2. after the heating period of four hours reached to end, the paraffin temperature was equal to 57.7oc, 50.6 °c, and 39.5oc in c1-r1, c2-r1, and c2-r2 respectively. which means that the paraffin was melted totally when the external surface temperature reached its maximum in both c1-r1 and c2-r1 and partially in c2-r2. 4. conclusion in this paper, practical experiments were made on different models of wall parts grafted with phase changing material. macro capsule filled with paraffin were embedded with the perforated bricks. the results of comparing the different wall models thermal behavior can be summarized by the following points: • the heat flux passing through the layers of the wall when radiating an amount of 900w/m² was equal to 33.8, 26.6, and 21.7 w for each of the rw, c1, and c2 respectively. after four hours of heating. • c2 wall was optimal since it has a lesser amount of heat flux which was calculated at the maximum external surface temperature for each amount of radiation. • the lowest temperature of the internal wall surface of sample c2 was recorded compared to the reference wall where the difference was more than 3 °c. while in c1 the difference was 2.5 °c less than the reference wall. the energy storage of the paraffin used in the experiment for each of the c1 and c2 walls were equal to 261kj and 522kj, respectively references uncategorized references [1] j. kośny, pcm-enhanced building components: an application of phase change materials in building envelopes and internal structures. springer, 2015. [2] r. j. khan, m. z. h. bhuiyan, and d. h. ahmed, "investigation of heat transfer of a building wall in the presence of phase change material (pcm)," energy and built environment, vol. 1, no. 2, pp. 199-206, 2020. [3] j. hu and x. b. yu, "adaptive building roof by coupling thermochromic material and phase change material: energy performance under different climate conditions," construction and building materials, vol. 262, p. 120481, 2020. [4] a. s. fleischer, thermal energy storage using phase change materials: fundamentals and applications. springer, 2015. [5] q. al-yasiri and m. szabó, "case study on the optimal thickness of phase change material incorporated composite roof under hot climate conditions," case studies in construction materials, p. e00522, 2021. [6] w. a. dukhan, n. s. dhaidan, and t. a. al-hattab, "experimental investigation of the horizontal double pipe heat exchanger utilized phase change material," in iop conference series: materials science and engineering, 2020, vol. 671, no. 1: iop publishing, p. 012148. [7] d. k. bhamare, m. k. rathod, and j. banerjee, "numerical model for evaluating thermal performance of residential building roof integrated with inclined phase change material (pcm) layer," journal of building engineering, vol. 28, p. 101018, 2020. [8] t. silva, r. vicente, n. soares, and v. ferreira, "experimental testing and numerical modelling of masonry wall solution with pcm incorporation: a passive construction solution," energy and buildings, vol. 49, pp. 235-245, 2012. [9] x. jin, m. a. medina, and x. zhang, "on the importance of the location of pcms in building walls for enhanced thermal performance," applied energy, vol. 106, pp. 72-78, 2013. [10] o. r. labed, m. b. al-hadithi, and o. t. fadhil, "experimental investigation of heat reduction through walls using phase change material," anbar journal of engineering sciences, vol. 7, no. 3, 2018. [11] a. a. abuelnuor, a. a. omara, k. m. saqr, and i. h. elhag, "improving indoor thermal comfort by using phase change materials: a review," international journal of energy research, vol. 42, no. 6, pp. 2084-2103, 2018. [12] https://www.moch.gov.iq/. (accessed. [13] y. a. cengel, s. klein, and w. beckman, heat transfer: a practical approach. wbc mcgraw-hill boston, 1998. [14] j. holman, "heat transfer tenth edition, ser," ed: mcgraw-hill series in mechanical engineering. mcgraw hill higher education, 2009. [15] e. m. alawadhi, "thermal analysis of a building brick containing phase change material," energy and buildings, vol. 40, no. 3, pp. 351-357, 2008. [16] a. bejan and a. d. kraus, heat transfer handbook. john wiley & sons, 2003. https://www.moch.gov.iq/ al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � study of solar water heating system with natural circulation in basrah dr.salman h. hammadi mechanical engineering department engineering college-university of basrah abstract theoretical analysis for solar water heating system in basrah city is performed. the analysis based on the thermosyphon principle in water circulation. the system consists of a tilt flat solar collector connected with isolated water tank by parallel tubes. all calculations are carried out according to basrah climate conditions in 21 january. the results show that the performance of the solar water heater depends on many parameters such as tilt angle and orientation of the collector, wind velocity, area of the collector, latitude, and solar time. in basrah where the maximum solar altitude angle in january is about 40, the optimum tilt angle of the collector is found to be closed to 50 degree. the storage water temperature is found to lie between 65 and 95 o c for the parameters ranges used in the investigation. this temperature range is sufficient for domestic uses in basrah city. keywords: solar water heater, natural circulation system, thermosyphon water heating ��7 �� "):�3 ا� '�d درا�2eو:� ا�(��!g ��7: ���h !ن "!ء�2 �"�j3" ��2!ن ه!h��!دي.د �5ا�34)�2 ا����!����1–آ��� ا�34)�2 8!"�7 ا� '�ة ا��>;� \ ����ue7 /�4 درا�� أ�rاء/0 �e) �4ام�� v �7 ا�����z ا�� ��n ا����� dq 9ت . ا��%�ة���ت ا�������aا �� �e7ا� d�q vwه������ a�@ ���أ ا���$uن ا���اري ا��راuآ��ue7ا�� dq v ����u���� dي � #�+ . ���و � ا��� ���k� n�� ���ue7ا�� vwن هu��/ � n� �au�k� c ا ا:cq �� �او�� na �%+ �4ان � ء �)�ول ��ار ;� 7 د . ا���uاز �� ا*(���* ت �����r y ا�����rأ �7 ا�� #�ة ا��7 ��8 ا��eوف إ�@�� dq م ا��%�ةu dq ٢١ d) ����ue7 ا���4 ن ا�d���z /)���� أداء إنأ��5cت ا���7 #l . آ (uن ا�? na \��� � q\ ا:acq�u� @ � ا����k ا�n� d��z ا���z وزاو�* \�� �7 . 8. ا�)�ض وا�y uإ�@ و���� dqا��%�ة ��� ٥٠ ��uا�d ا:c�q درu�/ \rن زاو � ��+ ا����k ا�d��z ا��?�@ na ٤٠ زاو � ار/$ ع ا�dq ��z آ (uن ا�? ( d�uا�d أ %@/��� �rدر. n� ��/ ا��4ان dq ء �7 ا��%�ة٩٥و٦٥و�r أن در�r ��ارة ا���� dq d��7�4ام ا����9� \�q � وهd آu�� �rدر . al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � nomenclature a collector area , 2 m a apparent solar irradiation, (w/m 2 ) b atmospheric extinction coefficient, (-) cp specific heat of water, (j/kg o c) d solar year day number with 1 st january c d diameter of collector tube, (m) g acceleration due to gravity ,( 2 s/m ) h height of tank, (m) h outside heat transfer coefficient, (w/m 2 o c) i solar intensity, ( )m/w 2 l latitude angle, (deg.) c l length of the collector, (m) f pressure drop coefficient ,(-) m mass of the storage water, (kg) m& water mass flow rate, (kg/s) n number of tubes in the collector, (–) re reynolds number,( ν c du ) u water velocity ,(m/s) t temperature, (°c) t time ,(hr) v volume of the storage water,(litter) w wind speed, (m/s) greek symbols α absorbitivity , (-) β solar altitude angle ,(deg.) δ solar declination angle, (deg.) θ surface incident angle ,(deg.) ψ solar azimuth angle, (deg.) γ surface-solar azimuth angle,(deg.) ϕ surface azimuth angle,(deg.) τ hour angle, (deg.) ρ water density ,( )m/kg 3 φ collector plane’s inclination to the horizontal, (deg.) β′ coefficient of expansion of water,( 1k − ) υ mean kinematics viscosity of water ,( s/m 2 ) p∆ pressure drops , ( )m/n 2 subscripts b buoyancy c collector f friction pressure drop m mean temperature s storage tank o or i outlet and inlet of the collector, respectively x function of x direction ∞ ambient al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � introduction hot water domestic uses are one of most common applications of solar energy. the solar water heating system consists of a solar collector and storage tank. the solar collector absorbs the solar energy and transmits to the circulating water in a form of heat. two ways are used to circulate the water in the system, the first is by pump and the other is by natural circulation due to the action of buoyancy force. the water heating solar system with natural circulation is the most interesting because of it is simple and most widespread technological device used for solar energy applications. many studies have been conducted on the solar water heating system.venkatesh[1]1994 presented experimental and theoretical study for domestic solar water heater with collector area of 1m 2 and storage tank of 0.16 m 3 .the maximum solar intensity is taken as 1000 w/m 2 and the overall heat loss coefficient is 5.5 w/m 2 o c. he found that the predicted maximum temperature of the storage water is 59.5 o c while the measured is 61 o c. haung[2] 1980 has developed a more general theory for parallel-plate absorber water heating systems with natural circulation of water between the plate and tank by representing solar radiation as a sine function of time. zerrouki et al.[3] 2002 presented an analysis of natural circulation of compact thermosyphon solar domestic heat water system. they assumed that the temperature distribution in the collector is linear. the temperature rise of the water and mass flow rate are measured and calculated. koffi et al.[4] 2008 presented a theoretical and experimental analysis of the thermal performance of a solar water heater prototype with an internal exchanger using a thermosyphon system. their results focus on the levels of the heat fluxes, temperature recorded, mass flow rate and efficiency of the collector. the results indicated that the heat fluxes peak reach 989 2 m/w , collector outlet temperature levels of more than 85.5 c o and the collector thermal effectiveness 58%. the present work is focused on a solar water heating system with natural thermosyphon circulation of water. the system analysis is presented for climate condition of basrah city in the south of iraq. the objective is to analysis the effect of geometry of the collector and solar radiation during the day as well as the collector tilt on the solar water heating system performance located in basrah city. theoretical analysis detailed information about solar radiation availability at any location is essential for the design and economic evaluation of a solar energy system. it is known that the direct solar radiation on a surface depends on the sun's position in the sky and orientation of the surface (see figure1). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � the sun's position is a function of the latitude (l), the solar declination ( δ ), and the time (t). from the fundamentals of solar geometry, these parameters are given by [5]. ] 365 360 )80dsin[(5.23 −=δ (1) )12t(15 −=τ (2) τδ+δ=β coscoslcossinlsinsin (3) the incident angle θ of solar beams on a surface tiled with the horizontal by angle φ is given by [6]: φβ+φγβ=θ cossinsincoscoscos (4) the solar azimuth angle is given by[6]: β τδ =ψ cos sincos sin (5) when the collector facing south, the surface azimuth angle ϕ is equal zero, so that ψ=γ and then: the solar intensity on a surface is given by [5]: θ= β− coseai sin/b (6) a and b are monthly dependent parameters tabulated in [5] 1.the solar collector the water mass flow rate through the collector can be evaluated from the heat and mass transfer balance between the buoyancy and pressure in the thermosyphon loop caused by the difference in densities of the hot and cold water and the pressure losses in the collector pipes according to the following equation(see figure2): fb pp ∆=∆ (7) where b p∆ indicates the driving force for the natural circulation, while f p∆ refers to the total pressure drops along the loop. b p∆ consists of two parts, one representing the pressure drop across the collector c p∆ and the other between the top and bottom of the storage tank s p∆ : scb ppp ∆+∆=∆ (8) the pressure due to the buoyancy force b p∆ can be evaluated by the following equation [3]: al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � ∫ −ρβ′+−φρβ′=∆ cl 0 iooi)x(ob h)tt(gdx)tt(singp (9) the temperature distribution in the collector tubes can be described by a linear equation of the following form: x l tt tt c io i)x( − =− (10) integrating equation (9) yields:       + φ −ρβ′=∆ h 2 sinl )tt(gp c ioob (11) at the equilibrium, the buoyancy force is equal to the friction resistance in the flow path, then:       + φ −ρβ′=∆=∆ h 2 sinl )tt(gpp c ioobf (12) the friction pressure drop in the collector tubes is expressed by: c c 2 f d2 lu f 2 1 p ρ=∆ (13) for a laminar flow, f is given by: ud 64 re 64 f c ν == (14) for set of parallel tubes (n) of the collector, the mass flow rate is given as: 2 c dun 4 m ρ π =& (15) or 2 c dn m4 u πρ = & (16) equations 12 to 16 give:       + φ −β′ρ= π ν h 2 sinl )tt(g nd ml 128 c ioo4 c c & (17) the temperature difference )tt( io − can be evaluated from the heat balance of the collector as follows: p mcc io cm )tt(ahai tt & ∞−−α=− (18) where al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � 2 tt t io m + = (19) the heat transfer coefficient as a function of wind speed is given by [7]: wind u38.2h += (20) 2. the storage tank by considering the storage tank insulated, the energy balance can be given as: )tt(cm dt dt cm iop s p −= & (21) the mass flow rate ( m& ) and the temperature difference )tt( io − vary with time as the solar incidence varies during the day. 3. solar intensity in basrah city as mentioned previously, the solar intensity can be calculated using equations 1 to 6. it is noted that the solar incidence on a surface depends on six variables: the solar declination )(δ , the latitude (l), the time )t( , the surface-solar azimuth angle )(γ , the surface azimuth angle ϕ( ), and the surface angle ( )φ . equation (6) represents the final equation where the solar incidence for any location can be calculated. basrah city lies on latitude (30.4 n), for a surface facing the south in 21 january, the data evaluated form equation (6) is fitted to the following formula:       π +φ+φ−φ= day t sin)6281017741103(i 23 (22) where day: is the time difference (in hours) between the sunrise and sunset. t : is the time (in hours) from the sunrise. the theoretical study is performed for the basrah climate conditions in 21 january. to obtain the desired results, the geometrical parameters using in this study can be summarized as: collector area 2 m3a = collector tube diameter c d =10 cm number of collector tubes n=20 volume of water storage 120 lit. absorbitivity 9.0=α the ambient temperature in basrah (21 january) for the last years(2004-2007) [8] is 7-17 c o and the wind velocity is 2-7 m/s. the water thermophysical properties used in the calculations is given by the following relations[9]: al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � 2 t003417.0t08832.01001 −−=ρ (23a) 32 p t0002656.0t0575.0t244.34226c −+−= (23b) 42 10)t0004.0t116.03.0( −−+=β′ (23c) 6 10)12.0 t0192.05155.0 1 ( − − + =υ (23d) results and discussion the solar radiation incident on the titled solar collector considered in this study depends on altitude angle ( β ) and the incident angle ( θ ) as shown in equation (6). these two angles can be easily evaluated from equations (3) and (4) respectively. figure(3) shows the altitude angle( β ) vs. time in 21 january and latitude (30.4 ). the altitude angle (β) increases from zero at sunrise to reach its peak value at solar noon and decreases after that to reach zero at sunset. in 21 jan. the declination angle is about -20 deg. and the maximum value of altitude angle (β) at latitude 30.4 is about 40 deg. in figure(4) the solar radiation incident on the tilted collector surface increases with increasing the tilted angle( φ ) to reach a maximum value at about 50=φ deg. and it decreases after that. this is because the maximum solar radiation is obtained when the collector facing a normal direct radiation. at solar noon the solar azimuth angle 0=γ and the equation (4) reduces to φ−β−=θ 90 . for a surface facing the south .deg40=β and the incident angle becomes φ−=θ 50 . it is clear that 0=θ when the tilt angle 50=φ which means a normal (maximum) solar radiation incident on the tilted collector surface. the differential equation (21) is solved numerically by euler method using equations (17 and 18) to calculate the hourly storage water temperature ( s t ). the results are shown on figures (5-10). figure (5) shows the effect of the tilt angle of the collector on the storage water temperature. it is noted that water temperature (ts) increases with the tilt angle for the range considered since solar radiation increases with the tilt angle for this range as it explained previously. as expected an increase of the collector area increases the heat absorbed by the water as it clear in figure (6). it is also noted the water temperature fall sharply for the larger area due to the increase of heat loss by the wind. this situation shown in figure (7) where the wind has a significant effect on the heat transferred to the water. when the wind velocity increases, the heat transfer coefficient increases and the heat loss from the collector increases which in turn a decrease in the water temperature. for a specified collector dimensions a quantity of heat absorbed by the al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � collector can be evaluated. when the volume of storage water is large, the water temperature decreases and the water requires more time to heat up as it shown in figure(8). in figure (9), a sine profile shown for the solar intensity with a maximum value in mid-day . the solar intensity increases with a tilt angle of the collector in a range reedeg6015 −=φ since the radiation approaches a vertical to the collector surface when the tilt angle is close to 50 degree as it shown in figure(4). figure (10) shows the water output temperature at the collector exit. it is noted that the water temperature o t increases with the tilt angle and reach a peak value when the tilt angle reaches 50 degree. after that it decreases since the radiation incidence is normal at about reedeg50=φ and a tilt otherwise. figure (11) shows a comparison between the present model and the experimental data presented by venkatesh[1]. the predicted storage water temperature is higher than that measured by venkatesh because the heat loss from the storage tank is neglected in the present work while it considered by venkatesh work. conclusions 1the optimum tilt angle of the collector facing the south in basrah during january is about 50deg. to the horizontal. 2a solar water heating system with a collector area of 2m 2 provides 120 litter/day of water at about 65 o c which is sufficient for domestic uses. 3the peak value of storage water temperature is always shifted from mid-day to afternoon due to the effect of heat capacity of water. 4the performance of the solar water heater is strongly depends on parameters like, the collector location, collector tilt, wind velocity, and the solar time. references 1. venkatesh, a., " experimental observations on a continuous flow type domestic solar water heater" j.energy convers. mgmt, vol.35, no.12, pp.1041-1048, 1994. 2. huang, b.j., "simirly theory of solar water heater with natural circulation", j.solar energy, vol.25, pp.106-116, 1980. 3. zerrouki,a., boumedien, a., and bouhadef,k., "the natural circulation solar water heater model with linear temperature distribution", j. renewable energy, vol.26, pp.549-559, 2002. 4. koffi, p m. e., andoh, h. y., gbaha, p., toure, s., and ado, g., " theoretical and experimental study of solar water heater with internal exchanger using thermosyphon system", j. energy conversion&management, vol.49, pp. 2279-2290, 2008. 5 .saleh, m. a., kaseb, s. and el-refaie, m. f., "glass-azimuth modification to reform direct solar heat gain", j.bulding and environment, vol. 39, pp.653-659, 2004. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � 6.ashrae handbook of fundamental . atlanta, ga, usa. 1993. 7.chow, t. t., he, w., and ji, j., "hybrid photovoltaic thermosyphon water heating system for residential application", j. solar energy, vol.80, pp.298-306, 2006. 8. www.wunderground.com/history/airport. 9.pissavi, p., "modeling of dynamic behavior of a tank for solar storage with internal exchanger", revue generale de thermique, pp.246-247, 1982. figure (1) solar angles for a titled surface. figure(2) natural circulation solar water heater system. north φ β θ south west γ ϕ ψ eest h c l l o t h s t i t φ storage tank solar collector solar radiation x al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � 6 9 12 15 18 21 0 3 6 10 20 30 40 50 60 70 80 time (hr) s to ra g e w a te r t e m p e ra tu re (o c ) φ=15 o φ=30 o φ=60 o 0 10 20 30 40 50 60 70 80 90 600 650 700 750 800 850 900 950 1000 1050 collector angle(φ o ) s o la r in te n s it y ( w /m 2 ) 7 8 9 10 11 12 13 14 15 16 17 0 5 10 15 20 25 30 35 40 time (hr) s o la r a lt it u d e a n g le ( β o ) figure (3) solar altitude angle in basrah(21 jan.) as a function of time. figure (4) variation of solar intensity with collector angle φ . figure (5) effect of collector angle on storage water temperature. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � 6 9 12 15 18 21 0 3 6 10 20 30 40 50 60 70 80 90 100 time (hr) s to ra g e w a te r t e m p e ra tu re (o c ) a=2 m 2 a=4 m 2 a=6 m 2 6 9 12 15 18 21 0 3 6 10 20 30 40 50 60 70 80 time (hr) s to ra g e w at er t em p er at u re (o c ) v=120 lit v=160 lit v=200 lit 6 9 12 15 18 21 0 3 6 10 20 30 40 50 60 70 80 90 100 time (hr) s to ra g e w a te r t e m p e ra tu re (o c ) w=1 m/s w=4 m/s w=8 m/s figure (6) effect of collector area on storage water temperature. figure (7) effect of wind velocity on storage water temperature. figure (8) effect of storage water volume on the water temperature. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � 0 10 20 30 40 50 60 70 80 90 55 60 65 70 75 80 collector angle(φ o ) c o ll e c to r o u tp u t t e m p e ra tu re (t o o c ) 7 8 9 10 11 12 13 14 15 16 17 0 100 200 300 400 500 600 700 800 900 1000 time (hr) s o la r in te n si ty ( w /m 2 ) φ=15 o φ=30 o φ=60 o figure (9) effect of collector angle on solar intensity. figure(10) output water temperature as a function of collector angle φ . figure(11) comparison between the present model and experimental data presented by venkatesh[1] . [1] article al-qadisiyah journal for engineering sciences 12 (2019) 207–213 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7806898150 e-mail address: dhaekh@yahoo.com (dhay mohammeda) https://doi.org/10.30772/qjes.v12i4.637 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. improving gypseous soil properties by using non-traditional additives dhay waddy mohammed a, balqeea a. ahmed a, maysam th. al-hadidi b adepartment of civil engineering, university of baghdad, baghdad, iraq. b department of water resources engineering, university of baghdad, baghdad, iraq a r t i c l e i n f o article history: received 16 september 2019 received in revised form 24 october 2019 accepted 01 november 2019 keywords: gypseous soil collapsibility copolymer permeability novolac polymer a b s t r a c t gypseous soils are common in several regions in the world including iraq, where more than 28.6% of the iraq surface is covered with this type of soil. this soil, with high gypsum content, causes different problems for construction and strategic projects. as a result of water flow through the soil mass, the permeability and chemical arrangement of these soils varies with time due to the solubility and leaching of gypsum. in this study, the soil of 36% gypsum content, was taken from one location, which is about 100 km southwest of baghdad. the samples were taken from depths of 0.5 and 1 m below the natural ground and mixed with 3%, 6% and 9% of copolymer and novolac polymer to improve the collapsibility, permeability and compaction parameters. the results of the experimental work showed a noticeable improvement of the collapsibility and permeability of the soil treated with polymer materials compared to the untreated soil. furthermore, adding 3% of polymer (copolymer and novolac polymer) materials gave the best improvement in collapsibility which reached a 44.5 and 46%, respectively, in 3 hours. the improvement in permeability reached 98.6% copolymer and 86.2% novolac polymer in 1 day. © 2019 university of al-qadisiyah. all rights reserved. 1. introduction gypseous soil is considered as one of the most difficult unsaturated soils in the construction of roads and buildings. the presence of the gypsum (hydrated calcium sulphate (caso4.2h2o)) in this soil affects its mechanical and physical properties and makes the soil more sensitive to the water. when water reaches gypseous soil from a heavy rainfall, it causes rearrangement of soil particles, and as a result volume change (decrease) occurs. this change in volume significantly causes a structural failure since the soil loses the bond between the particles and becomes weak to withstand and resist the load applied on it depending on the soil nature and geological structure, the primary soil density, soil structure, the imposed stress, and the amount of wetting [1,2]. in civil engineering the soil can be classified as gypseous soil depending on the amount of gypsum content in it, regardless of soil color or shape. several researchers indicated that a certain percent of gypsum should exist, such as, 3%, 4%, 6% as a lower limit [3].these rates of gypsum have high effects on the physical and mechanical characteristics of soil, and these effects occur unevenly in the soil according http://qu.edu.iq/ https://doi.org/10.30772/qjes.v12i https://en.wikipedia.org/wiki/baghdad 208 dhay mohammeda, balqeea ahmedb, maysam al-hadidic/al-qadisiyah journal for engineering sciences 12 (2019) 207–213 to the amount of gypsum. to reduce the damage caused to the structure, the gypseous soil should be improved in two ways: mechanical and chemical. the mechanical method is a physical process done by removing and/or adding another soil. the chemical method is made by adding a chemical substance that can change soil properties by means of chemical reactions [4,5,6]. it has become necessary to use non-traditional suburb materials to achieve the economic and environmental considerations such as polymers and resins, which are characterized by their effectiveness in a short time. however, there is still rare information about non-traditional suburb materials especially for polymers. however, for economic reasons the chemical composition of polymer is unknown by the companies, which made the researchers looking for its result in improvement rather than on performance mode. since polymers and resins are not widely used in the past, it has become necessary for many researches to investigate the effect of these additives on the engineering soil properties of gypseous soils. in 2010, al-numani [7] took a soil sample from najaf that contains 35% of gypsum and treated it with different rates of cement content (4-8%). the conducted laboratory tests indicated that increasing the cement content produced an increase in both the optimum water content and maximum dry density to (23.3 and 7.6%). vahid and mohsen [8] used two types of polymer to improve sandy soil and found an increase in compression strength from 0.03 mpa to 5.2 mpa. al-neami [9] used (2, 4, and 6%) clinker additive to treat gypsum soil from al-exandria, babylon, and found that the best clinker ratio was (4%) which decreased the collapsibility of soil. fattah and salman [10] used dynamic compaction method to test three gypseous soil samples with 27, 41.1, and 60.5% gypsum content. the number of blows used in this study were between 20 and 40. also, three heights of the drop were used: 35, 50, and 65 cm. the experimental results showed that the best compressibility was obtained when the samples compacted to 20 blows. the results also showed that the dynamic compaction had a greater effect with increased gypsum content. aldaood and al-kiki [11] used samples with 20% gypsum and improved by 4% lime and the samples were treated for 2 days. the results showed that when increasing the water velocity through the soil mass, the weight of soil and gypsum are decreased. they noticed a reduction in strength with increasing soaking time. aldaood and al-mukhtar [12] studied the effect of soaking on the mechanical properties of gypseous soil that was treated with 3% lime and cured for 28 days. it was noticed that a long time soaking had a great effect on the unconfined compressive strength and volume change of the stabilized soil particles. fattah, et .al. [13] used four samples of gypseous soil with different percentages and treated them by grouting acrylate liquid to reduce the compressibility. the treated samples showed that the acrylate liquid reduced the compressibility of the soil by more than 60–70% and this behavior may be attributed to the fact that acrylate liquid coated the soil particles, and thus, isolated them from being subjected to the effect of water. the improved samples showed a low collapse potential where acrylate liquid reduced the collapsibility of samples by more than 50–60% and increased the cohesion of the soil. majeed et .al. [14] took two sandy clay samples from the albasra governorate and improved them by the cement of a percentage of 2, 4, and 6% and by novolac polymer with percentages of 0.2, 0.4, and 0.6%. the test results showed that these ratios were sufficient to obtain a high dry density and increase the strength by 15 and 18.75% with a duration of less than three hours. however, the addition of 6% cement and 0.6% novolac polymer led to increase the maximum dry density by 2.33 and 3.5 % and the angle of internal friction but reduced the optimum water content. furthermore, this method reduced the cost by 50% compared to the method of replacing soil with sand. ibrahim and mahmood, [15] took two gypseous soil samples from baiji and al-thurthar and mixed them with 5, 2.5, and 6% of hydrated lime, hydrated calcium chloride, and kaolin to improve the collapsibility of soil. it was found that the calcium chloride and kaolin achieved the best results while the lime reduced the soil collapsibility to a small degree. ibrahim and schanz [16] used a mixture of 30% of silber sand and 70 % of pure gypsum and treated it with different percentages of silicone oil to improve the engineering properties. the study results showed the silicone oil was able to improve the collapsibility and shear parameters of the gypseous soil. alhadidi and al-maamori [17] used gypsum soil samples with 42.55% gypsum from karbala city. different water cement ratios (w/c) were used to decrease the collapsibility of the earth canal and the results showed that 2 % of w/c led to decrease the collapsibility of soil. vahid and mohsen [18] took sand samples from kerman city, iran, and mixed them with 2, 4, and 6% of polymer with different periods of treatment (3, 7, and 28 days). they found that when the polymer content increased to 6%, the unconfined compressive strength increased by (66.31 %) in 28 days compared with 3 days. al-hadidi. and ibrahim [19] used 6, 10, and 12% of polyurethane to reduce the soil erosion of the irrigation canal which was made from gypsum soil in karbala city with 41% gypsum. the researchers found the best percentage to use was 10% which reduced the erosion by 86.2%. the main goal of this study is to improve the properties of gypsum soil (collapsibility, permeability and compaction parameter) with small quantities and suitable prices by using new non-traditional materials, so the materials that used are copolymer and novolac polymer. 2. materials and experimental procedure 2.1. materials 2.1.1. gypseous soil to achieve the purpose of study, natural gypseous soil of 36% gypsum; is taken from one location about 100 km southwest of baghdad. the samples were taken from depths 0.5 – 1 m below the natural ground surface. the unit weight of the soil in the location was 14.5 kn/m3 and the natural water content 5%. the undisturbed soil samples were air dried, made homogenous, put in plastic bags, and transported to soil mechanics laboratory at civil engineering department, college of engineering at aiqadisiyah university to evaluate the engineering properties of the soil. 2.1.2. copolymer copolymer is a mix of non-ionic environmentally safe co-polymer products, where it is considered a new material used for treatment. the material is diluted with water and added to the soil and characterized by the following properties [20]:  do not pollute groundwater.  safe to plant and animal life in the soil.  contains soil moistening agents.  good resistance to the ultraviolet rays.  good resistance to erosion.  penetrates the soil or any particulate materials. table 1. shows the technical properties and form of copolymers [20]: 209 dhay mohammeda, balqeea ahmedb, maysam al-hadidic/al-qadisiyah journal for engineering sciences 12 (2019) 207–213 table 1. the properties of copolymers element style color white (transparent once dried) form liquid specific gravity 1.03 solid content 20-22 % viscosity 300 – 350 mpas surface tension 40 mn/m freezing point ºc 0 boiling point ºc 100 ph 5.5 2.1.3. novolac polymer novolac polymer can be defined as the reaction between phenolformaldehyde and phenol in acid catalyst media and it involves 5 to 6 % of gasoline rings per molecule. the common properties of novolac polymer are [21]: 1. it has a small molecular weight and it is thermoplastic. 2. porous arrangement with less mechanical possessions. 3. the curing reaction for the novolac polymer is carried out over 100 ºc. 4. it has a density of 1 to 2 % of the density of natural soil and has a color ranging from yellow to orange. 2.2. experimental work 2.2.1. compaction test standard procter compaction test was carried out following (astm 698) method a [22]. a mold of 10 cm in diameter and 16.5 cm in height was used. the samples were compacted in three layers with 25 blows for each layer using a 2.5 kg hammer which is dropped from 30.5 cm height and this test was carried out for treated and untreated soils. 2.2.2. collapse test single collapse test was carried out according to the guide proposed by jennings and knights [23] and astm d5333 [24] on natural compacted and treated gypseous soil samples with various ratios of co-polymer, novolac polymer. the dry weight of specimens was obtained to determine the change in compressibility properties of gypseous soil by using specimens equipped with a ring that was 50 mm in diameter and 19 mm in height. the samples were left in the water for 24 hours with a pressure of 200 kpa and then additional static load was applied until it reached 800 kpa then samples were unloaded. the collapse index is obtained from the formula below by using (e-log p) graph under the effect of a certain stress level. ……………………………………………………(1)     e e pc 1 . where: c.p = collapse potential. δe= void ratio before and after soaking. eo= initial voids ratio. 2.2.3. permeability test permeability test was performed for all samples (treated and untreated soil) according to astm d-2434 [25]. a mould with 10 cm in diameter and 13 cm in height was used. the mould was connected at the top inlet to a water source at a height of 180 cm. the mould had a side outlet at the bottom for the water to flow out of the sample. the quantity of flow for a certain period was collected and recorded. the permeability coefficient was calculated using the equation: …………………………………………………………(2)  ia q k   where: k = coefficient of permeability. q = v/t quantity of water discharged. l = the height of the mold. a = cross-sectional area of mold t = total time of discharge. h = the loss of water. 2.2.4. physical test the specific gravity of the soil is determined according to bs 1377[26], but kerosene was used instead of water due to the dissolution action of gypsum in water. the soil was subjected to grain size distribution test according to astm d422 [27] to classify the soil. fig. 1. clearly shows that the soil can be classified as poor grade sand (sp) according to the unified soil classification system (uscs). the engineering and physical properties of the soil are shown in table 2. figure 1. grain size distribution of gypseous table 2. the results of the classification of soil test and physical properties of gypseous soil. physical property value standard of the test maximum dry unit weight 𝛾d(max (kn/m 3) 16.28 astm, 698 [22] single collapse (%) 9.47 astm d5333 [24] permeability (cm/sec) 1.7×10-3 astm d-2434[25] specific gravity, gs 2.54 b.s1377:1975[26] d10 0.1 astm 422[27] d30 0.19 -- d60 0.3 -- coefficient of curvature, cc 1.203 -- coefficient of uniformity, cu 3 -- unified classification system sp -- optimum water content wopt (%) 11 astm, 2216[28] 210 dhay mohammeda, balqeea ahmedb, maysam al-hadidic/al-qadisiyah journal for engineering sciences 12 (2019) 207–213 2.3. chemical tests several chemical tests were carried out on the soil as shown in table 3. these tests included: 1. gypsum content which was determined by using the hydration method recommended by nashat and al mufty [29] and s.o.r.b/r6[30]. the hydration method consisted of oven drying the soil sample at 45 ℃ until the sample weight became constant. the sample weight at 45℃ was recorded. after that, the same sample was dried at 110℃ until the weight became constant and recorded. the gypsum content was found according to the equation: ) 3…………………………( 100 45 778.4)11045( %     cw cwcw x where: x = gypsum content (%). w45°c = weight of the soil sample at (45°c). w110°c = weight of the soil sample at (110°c). 2. total sulfate constant ( so3) test this test was carried out according to s.o.r.b/r6.in this test natural gypseous soil was used as follows: 1. take 2 g of soil and add 200 g of hydrochloric acid at a concentration of 10%. 2. heat the sample to boil and filter using filter paper no. 42. 3. remove the sample from the heating and add 25 ml of barium chloride with 5% concentration and leave it for the second day. 4. filter the sample using filter paper no.54 and wash the precipitate well with hot water until cleaned and place it in a weighted beaker. 5. put the beaker in the oven to 850℃ for a quarter of an hour and then leave it to cool and take the weight. so3 was found according to the equation: ................................(4)……………… w ww so 3.34)12( %3   where: w: the weight of the sample. w1: the weight of the sample after heating. w2: the weight of the sample after heating. 3.total soluble salts ( t.s.s) test t.s.s test was performed according to s.o.r.b/r6 on natural gypseous soil as follows: 1. take an empty weighted beaker. 2. place 25 ml of the filtrate sample in the beaker and heat to dry. 3. remove the sample from heating and leave it to cool and then take the weight again. t.s.s was found according to the equation: …………………………………………..(5)   v ww sst 610)21( ..   where: w1: the weight of beaker before heating. w2: the weight of beaker after heating. v: the volume of filtrate. 4. the x-ray test the x-ray tests were carried out on natural gypseous soil identifies the clay and non-clay minerals. these tests were carried out with the assistance of the laboratories of the state company of geological surveying and mining. results of the x-ray diffraction test are shown in table 4. and table 5. shows the details of the test designation. table 3. the results of chemical properties tests of gypseous soil chemical property value natural value standard of the test total (so3%) 13.87 5% s.o.r.b/r6 [30] total soluble salts (t.s.s %) 9.8 max 10% -- gypsum content (%) 36 max 10.75% -- ph value 8.21 0-14 -- o.m (%) 0.86 max 2% b.s 1377-3-1990 [31] table 4. the results of the x-ray test of gypseous soil element wt. % wt. % sigma o 53.46 0.3 na 0.56 0.07 mg 1.8 0.07 al 3.4 0.08 si 20.08 0.18 s 5.06 0.1 k 1.64 0.07 ca 11.65 0.14 ti 0.13 0.06 table 5. details of the test designation test designation soil state 0g gypseous soil without any added material 3gp gypseous soil with adding 3% of copolymer by weight 6gp gypseous soil with adding 6% of copolymer by weight 9gp gypseous soil with adding 9% of copolymer by weight 3gn gypseous soil with adding 3% of novolac polymer by weight 6gn gypseous soil with adding 6% of novolac polymer by weight 9gn gypseous soil with adding 9% of novolac polymer by weight 3. analysis and discussion of the results 3.1. compaction test the results of the compaction test are shown below in fig. 2. and fig. 3. figure 2. results of compaction test of gypseous soil treated by different percentage of copolymer 211 dhay mohammeda, balqeea ahmedb, maysam al-hadidic/al-qadisiyah journal for engineering sciences 12 (2019) 207–213 figure 3. results of compaction test of gypseous soil treated by different percentage of novolac polymer several observations can be drawn from fig. 2. and fig. 3.as illustrated in the following: 1. little change was observed in the dry unit weight of the improved soil where it increased with increasing the polymer material to 3%. this behaviour may be attributed to the fact that these materials filled the voids between soil particles and had low specific gravity which let them replace some of the soil mass. subsequently, this led to create a new structure with a large volume and decreased sample weight. 2. the optimum moisture content seemed to stay constant in percentages of 6% and 9% of the co-polymers where these materials worked as waterproof while it began to increase with increasing novolac polymer percentage to 9% where the novolac polymer (solid form) needed more water to attach to the soil particles. table 6. the result of compaction test of the gypseous soil treated by copolymer and novolac polymer materials maximum dry unit weight(kn/m3) optimum moisture content (%) 0g 16.28 11 3gp 16.77 13 6gp 16.59 8 9gp 16.51 8 3gn 17.18 13 6gn 16.5 16 9gn 16 17 3.2. collapse test the samples that were used in this test were compacted to 16.28 kn/m3 maximum unit weight and 11% optimum water content. as a result of the high gypsum content for natural soil that was used in this research (which is 36%), the collapse potential was 9.47% which was classified as moderately severe (explained in a drop of the curve for natural soil in figs 4 and 5) according to the astm d5333. the addition of polymer materials caused a reduction in the collapse index depending on the amount of improving materials. figs 4 and 5below shows the results of collapse tests for samples. figure 4. results of single collapse test of gypseous soil treated by different percentage of copolymer figure 5. results of the single collapse test of gypseous soil treated by different percentages of novolac polymer. 212 dhay mohammeda, balqeea ahmedb, maysam al-hadidic/al-qadisiyah journal for engineering sciences 12 (2019) 207–213 the collapse index decreased with increasing polymer materials to 3%. this behaviour of soil may be attributed to the fact that these materials covered the soil particles and increased the bonding action between the soil particles. on the other hand, after 3% polymer content, the polymers made soil particles flocculate and slide causing a drop in soil cohesion. this made the structure of the mass weak and increased the collapse potential, volume of samples, and reduction in dry unit weight. the results are shown in table 7. and table 8. table 7. the results of a single collapse test before and after improvement materials (%) collapse index, ie (%) 0g 9.47 3gp 5.26 6gp 6 9gp 6.57 3gn 5.16 6gn 6.31 9gn 7.8 table 8. the summery of decrease in collapse potential materials (%) improving in collapse index, (%) 3gp 44.5 6gp 36.6 9gp 31 3gn 46 6gn 33.4 9gn 17 3.3. permeability test: all the results of the permeability tests are shown in table 9. in this test the natural and treated soil samples were compacted to the maximum dry unit weight. it was noticed that the soil showed high reduction in the permeability coefficient with the addition of the additive materials. the polymer materials worked as waterproofing, covered the gypsum particles, and filled the voids causing reduction in gypsum dissolution and subsequently the destruction of soil mass structure. table 9. results of permeability test before and after improvement materials (%) coefficient of permeability (cm/sec) 0g 1.7 ×10 -3 3gp 1.98×10-4 6gp 2.3×10-5 9gp 5.1×10-5 3gn 5.31×10-4 6gn 2.35×10-4 9gn 3.69×10-4 4. conclusions 1. the maximum dry unit weight increased with adding polymer materials to 3% and began to decrease after that. also, clear changes in optimum water content were observed where optimum moisture content decreased to 8% with increasing the copolymers and increased to 17% with added the novolac polymer. 2. high reduction in collapse potentials was noticed by increasing the polymer materials to a small amount (3%) from the copolymer and novolac polymer and the improvement reached to 44.5 and 46%. 3. the coefficient of permeability had lower value with the addition of 6% of the copolymer and the improvement reached 98.6%, while with adding 6% of the novolac polymer the improvement reached 86.2%. 4. in terms of cost, these materials are expensive. the basic structure of these materials is oil derivatives and the high price of it is due to the technology used in manufacturing and importing as mentioned before. however, if there is a production factory inside the country that provides such kinds of additives, the cost might be lower or even close to the cement price. reference [1] ahmad, f., m.a. said and l. najah, (2012): ''effect of leaching and gypsum content on properties of gypseous soil '', ijsrp, vol. 2 (9), pp. 1-5. 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[27] american society for testing and materials (astm), "standard test method for particle size analysis of soils ", astm d422 international, west conshohocken, pennsylvania, usa, 2002. [28] astm, d 2216 standard test methods for laboratory determination of water (moisture) content of soil and rock by mass. west conshohocken: american society for testing & materials, 2005. [29] al-mufty, a.a .and nashat, i.h, "gypsum content determination in gypseous soils and rocks", 3rd international jordanian conference on mining , (2000) pp,500-506. [30] sorb/r6 "iraqi standards for roads and bridges" general organization for roads and bridges, baghdad, iraq, 1983, [31] british standard institution, 1990, methods of test for soils for civil engineering purposes. bs 1377–1990: part 1, 2, and 3, london, 133 p. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٥ heat transfer behaviour in a two-phase bubble column dr.balasim a. abid dr. rahman sh. abdulmohsin mr. hisham m. al.tamimi university of technology thi-qar university al-qadisiya university chemical department mechanical department chemical department abstract time-averaged local heat transfer coefficient profiles were studied in a 0.2 m bubble column diameter using air-water system. the effects of the superficial gas velocity and axial locations (z/d) on the heat transfer coefficient and its radial (r/r) profiles were investigated in bubble column. significant differences were observed between heat transfer coefficients in the axial directions viz. in the bulk flow region (z/d=4.8) higher than in the distributor region (z/d=0.28) by 15% -23% for increasing the superficial gas velocity from 0.03-0.35 m/s. the heat transfer coefficient increase with superficial gas velocities and the values in the center of the column were 8–12% greater than those near the wall region .the characteristics of bulk flow region have large variation in radial direction and little in axial direction for the values of heat transfer coefficients. keywords: bubble columns; large-scale; heat transfer coefficient; axial location; radial profile. ���ك ا�3'�ل ا�!�ارة 0. ا�) �د ا�/'��. ذات ا� �ر�+ ـــــــ. ه;�م �! � ا�� � ر6 + : �+ ��� ا� !9+ . د ــــــ����7 ا6 � ��.د ��)��� (��)� ا�'�د��� (��)� ذي ��ر ا����)� ا��= ا�% ��� ا�=� ��و�� ا�% ��� ا� �=��3=�� ا�% ��� ا�=� ��و�� ا���#� x c< #"�0$ د%� +ت اo �0ل ا � ارة $# "�� ��ءم و��8 m7ام �koم ا 5%اء�4٠.٢ درا38 4%ز�� c�$ �4 8 "3 ا ��ز . ا � اo �0ل ا � ارة�� ���%ري وا %ز�� ا c0 ي "' �%د ا !�0"# وا(ر4!�ع ا� +ت . $# ا�� 9/� 3�5 +�3k $ و>�ت �4 ��%ري � اo �0ل ا � ارة $# �30c ا fg/� ا �م، اo �0ل ا � ارة ��(x��4 ا�� � اo �0ل ا"'� (z/d=4.8)اي �� 9 �%زع � % ١٥ ��3�i (z/d=0.28) ا � ارة $# �30c ا � / م٠.٠٣ $# 8 "3 ا ��ز 9 ة '<��د% ٢٣إ .�f/ م�f٠.٣٥ ا +ت اo �0ل ا � ارة 4<داد �<��دة 8 "3 ا ��ز �� ، 3�i�� ��%د ا"'� آ< ا m�" �/0 � % ٨وا 9 ا 0/� > ب ا �mار% ١٢ا . fg �30c ا #$ ch�a7 +ت اo �0ل x/� ا �م آ�vo أآj �4/ ا ��(��4ا�� �/0 3�i� ��%ري �� ا c0 ي وا>� ��(x��4 ا .ا � ارة al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٦ nomenclature d diameter of the column m h heat transfer coefficient kw/m 2 . a probe heat transfer area m 2 k l test section of column m n number of data points -- q heat flow rate kw r radial location m r radius of the column m t temperature k vg superficial gas velocity m/s ∆x thickness of thermal barrier m z axial location from bottom m subscripts avg average b bed g gas i instantaneous s surface introduction: bubble column is regarded as one of the most important multiphase flow systems, which is widely used in many industrial applications including chemical, biochemical, petrochemical, environmental and metallurgical processes(abdulmohsin,2008). the industrial importance of bubble column remains undisputed mainly due to the advantages that it offers from absence of moving parts, leading to easier maintenance, simple construction, high effective interfacial area, excellent temperature control and high heat and mass transfer rates caused by strong gas-liquid interactions. usually bubble columns operate in either a bubbly flow (homogeneous) regime or churn-turbulent flow (heterogeneous) regime depending on the chemical reaction and the system characteristics introduced (shaikh, 2007). recently, in many of the commercial installation and industrial applications of bubble columns the churn-turbulent flow regime has been found of considerable and practical interest (dhotre, 2005). design and scale-up of bubble columns are critical due to the complexity of non-linear hydrodynamics. since the use of large-scale bubble column is desirable because large gas throughout can be achieved which causes increasing liquid circulation intensity that affect the acceleration of the bubbles and as a result decreasing the gas al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٧ holdup. additionally, larger heights are needed to obtain the desired residence time distribution (rtd) to achieve the larger conversion level. in many industrial processes where bubble column found applications, thermal control is of importance because the reaction is usually accompanied by heat supply or removal for the endothermic or exothermic operations, respectively. therefore, maintaining desirable bulk media temperature is necessary because it plays an important role in the performance of the reactor. hence, the knowledge and understanding of heat transfer phenomena and quantity of the heat transfer coefficients are essential and required for proper safe, efficient design and operation of these reactors. thus, significant studies on heat transfer in bubble column has been conducted and reported in literatures (abdulmohsin, 2008). in general, these studies can be divided into: i) estimation of wall-to-bed heat transfer and ii) estimation of inserted objects-to-bed heat transfer. however, most of these studies are concerned with the steady state time-averaged heat transfer coefficients (wu, 2007). it is noteworthy that the local time-averaged heat transfer coefficients and their radial profiles or cross-sectional profiles that closer, provide valuable insight into mechanisms of heat transfer and qualitatively the bubble dynamic and liquid circulation intensity in bubble column. (saxena and chen,1994) reviewed the pervious investigations that have measured the heat transfer coefficients in bubble columns based on the measurements of energy input method using slow response assembly probe (for more details see (abdulmohsin,2008). recently, heat transfer coefficients have been measured based on the measurement of the directed heat flux with aid of fast response advanced probe. however, most of these studies were performed using up to with 0.16 m column diameter. therefore heat transfer coefficient is still poorly in large-scale diameter bubble columns to avoid wall effects. in additions, the measurements of heat transfer have been restricted to few locations inside the column and there is a strong need for detailed experimental measurements for local timeaveraged heat transfer coefficient. this investigation focuses for the first time on the study of local heat transfer coefficients and its behavior in a larger diameter (0.٢٠ m) bubble column using high response heat transfer probe. the experimental measurements have included many locations inside the column starting from the distributor region up to within the fully developed bulk flow region. the use of fast response and movable heat transfer probe has provided the instantaneous heat transfer measurements at different axial and radial positions, over a wide range of superficial gas velocity of practical importance. hence, the effects of the superficial gas velocity on the heat transfer characteristics are analyzed. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٨ experimental work: experiments were conducted in a large-scale grid of plexi glass column of 0.2m internal diameter and height ٢.65 m (figure 1). the column was supported by rigid metallic structure to keep it vertical and to minimize the mechanical vibrations which might affect the measured heat transfer signals. oil-free compressed air constituted the gas phase, while tap water was used as the liquid phase. the effects of liquid velocity are small or negligible in bubble columns, therefore the experiments conducted in a semi-batch mode; continuous in relation to the gas flow and batch with reference to the liquid flow. gas flow was supplied by two compressors connected in parallel, after it passed through a dryer and several air filter units. the flow rate of the filtered dry air was adjusted by a pressure regulator and rotameters system, consisting of two rotameters from engineering, inc. (omega hfl6715a-0045-14) connected in parallel to increase gas velocity range. the superficial gas velocity was varied in the range of 0.0٣ -0.٣5 m/s which cover both bubbly and churn-turbulent flow regimes. air was introduced into the column through a perforated plate gas distributor with 241 holes of 3 mm diameters and the open area is 5.42%. during the experiments the dynamic liquid height was maintained at around ٢.2 m (equal to 11d times) by varying the static height at each studied condition. it was found that the range of static height variation does not affect the column hydrodynamics at the conditions studied (wu, 2007) . the temperature was maintained at about 21 o c in the column and during the experiments, the liquid phase was regularly replenished due to the loss of small liquid quantity because of evaporation. copper-constant thermocouples (omega tmtss-125u-12) were arranged at various axial positions and located at different radial locations to monitor bed temperatures of the media in the column adjacent to the heat transfer probe. a fast response heat transfer rode type probe with 11.4 mm diameter and 38 mm length of the brass shell were used for the measurements. the heat flux sensor (overall dimensions 11mm×14mm×0.08 mm) used on the probe is from rdf corporation (micro-foil heat flow sensor no. 20453-1), which measures simultaneously both the local heat flux and the surface temperature of the probe. the response time of the sensor is about 0.02 s (more details of the probe design are given by abdulmohsin, 2008 ) . during experiments, the heat transfer probe was horizontally introduced into the bubble column and moved radially from center to wall region, at r/r =0, 0.3, 0.65 and 0.9, respectively. four different axial heights to column diameter ratios (z/d) were used of 0.28, 1.6, 3.2 and 4.8, respectively, that cover sparger to bulk regions. the measurements were al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٩ performed two-three times at each condition and the average values are reported. since the measured signals of the heat flux are in the range of micro-volts, they were amplified before received by the data acquisition system. after being amplified, the heat flux signals, together with the signals from the thermocouples, were sampled at 50 hz for more than 40 s. the, instantaneous heat transfer coefficient can be determined by direct measurement of heat flux and the difference between surface and bulk temperatures at a given time: bisi i i tt aq h − = (1) where (kw/(m 2 .k)), i q the instantaneous heat flux across the sensor (kw/m 2 ), si t the instantaneous surface temperature of the probe (k) and bi t the instantaneous bulk temperature of the media (k).the local time-averaged heat transfer coefficient at a given location was obtained by averaging the instantaneous heat transfer data over a large number of sampling points as follows: ∑ = − = n i bisi i ava tt aq n h 1 1 (2) where n is the total number of data points, in this work 2050=n samples to establish a high stable value of heat transfer coefficients for all operating conditions. results and discussion: 1 effect of superficial gas velocity the effects of superficial gas velocity were investigated for different axial locations at four radial positions from the center of the column towards the wall viz. r/r=0.0, 0.3, 0.65 and 0.9. figures 2 a and b show the heat transfer in the center (r/r=0.0) of the column and near the column wall (r/r=0.9). it can be seen that the strong influence of the superficial gas velocity on the heat transfer coefficients between the bubbly and churn-turbulent flow regimes is evident. in the center region of the column for bulk flow region (z/d=4.8) increasing in the superficial gas velocity from 0.0٣-0.٣5 m/s causes increase in the average heat transfer coefficients by about 1.3 times . for all axial levels, both the heat transfer coefficients in the center region and those in the wall region initially increased rapidly with the superficial gas velocity in the bubbly flow regime towards the transition regime, and the increase became smaller at higher superficial gas velocities (within the churn-turbulent flow regime), this must be related to the fact that at low superficial gas velocity the small bubble sizes are formed in bubbly flow regime. when the al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٣٠ superficial gas velocity increase some definite value, the transport mechanism for large bubbles with their individual rates of rise increase gradually to apply for the transport of the gas through the dispersion two-phase and large coalescence bubbles then arises, so that a significant gas transport occurs through the large bubbles which occurred in churn-turbulent flow regimes which caused slowly down in heat transfer coefficients. in addition, when the superficial gas velocity continuing increased, the magnitude of the increase in heat transfer coefficients began approaches asymptotically to constant values in the churn turbulent flow regime, since faster bubbles coalescence and breakup come to balance at a certain velocity. on the other hand, it can be seen that the heat transfer coefficients in the center are larger than those in the wall region, and the amount varies from 9% to 13% with the increase in the superficial gas velocity from 0.0٣ to 0.٣5 m/s for bulk flow region (z/d=4.8). these differences at low superficial gas velocities are relatively small, but at higher superficial gas velocities the differences became larger. this reflects that bubbles with relatively small diameters are uniformly distributed across the column radius at low superficial gas velocities. with a further increase in superficial gas velocity, large bubble are formed , and most of them rise through the core region of the column at high bubble frequency, caused high gas holdup in the center region. however, most small bubble moves in the wall region of the column, where the liquid flow downward at low bubble frequency causing low gas holdup (wu,2007). in the four axial locations, the heat transfer coefficients in the center of the column are greater than that in the near wall due to the fact that large bubbles exist at center and they are more effective in enhancing heat transfer in the system. 2 effect of probe axial location for the first time, the profiles of the heat transfer coefficients along different axial locations in bubble column were provided at several superficial gas velocities for different radial locations from the center to the wall regions, as shown in figure 3 a and b .the results show that, the local heat transfer coefficient increases gradually as the distance from gas distributor increased along the column height and that indicated the liquid column above the gas distributor can be divided into three different sections. section one in the bottom of column, referred to distributor region (z/d=0.28) where the bubble properties are determined by the bubble formation process at the gas distributor and this region characterized by small bubbles. section two in the height of the column located less than twice diameter of the column where the bubbles began growth and al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٣١ their properties depend on what happens in region one of the column and on the bulk liquid phase motion, this referred to the developing region (z/d=1.6). section three is the intermediate and top parts of the liquid column where gross recirculation established, gas liquid phase separation began take place and large bubbles completely formed with fast flow; this refers to the bulk flow regions (z/d=3.2 and z/d=4.8). from figure (3),it can be seen that the heat transfer coefficients increase dramatically to the maximum at around ١10 cm (z/d=4.8) away from distributor, the same location of fast bubble flow region. in additions, heat transfer coefficients in the bulk region (z/d=4.8) are significantly higher than the distributor region (z/d=0.28) and the differences increase from 14% 22% with increase of superficial gas velocity from 0.05-0.45 m/s in the center of the column, these differences indicate that different heat transfer processes dominate those two flow regions. on the other hand, there are small differences and similarity in axial heat transfer coefficients profiles in the intermediate and top sections, indicating the overall mixing behavior in these regions could be similar at fully developed flow regions and no significant axial variation are observed. while at developing region (z/d=1.6) the heat transfer coefficients still lower than both two bulk regions, but do not seem to reach below the distributor region, this attributed to growth of bubbles in this region towards the gas flow direction. if the data are normalized with respect to the maximum heat transfer coefficients at fully developed bulk flow region (z/d=4.8), as shown in figure 4 a and b. it can be seen that the axial profiles are similar for higher superficial gas velocities, but are different for low superficial gas velocities. this indicates similarity of hydrodynamics in fully developed churn-turbulent flow regime that developing for higher superficial gas velocities. the slopes at high superficial gas velocities are more than for the high superficial gas velocities. 3. profile of heat transfer coefficients the radial heat transfer coefficients were measured by moving the probe along the column radius at four different positions from center to the wall of the column. figure 5 a and b show the local radial profiles of heat transfer coefficients obtained at different axial locations with high and low superficial gas velocities. it can be seen that at the same superficial gas velocity for the fully developed bulk flow region (z/d= 4.8), the local average heat transfer coefficient reduced by 9% for low superficial gas velocity (vg = 0.0٣m/sec) while it reduced by 13% for high superficial gas velocity (vg= 0.35m/sec). in addition, these comparisons for variations of the local heat transfer coefficients at center and wall at low and higher superficial gas velocities al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٣٢ showed that the heat transfer coefficients at wall significantly smaller than that of the center, this indicates that wall region is relatively free from large bubbles or faster moving bubble chain. from figure 5 a ,it was shown that the radial differences are observed to be small in the distributor region (z/d=0.28) indicating more radial uniformity in this region at high superficial gas velocity (vg > 0.1m/s) and the less uniform at low superficial gas velocity due to more differences in heat transfer coefficients. from figure 5 b, the radial profiles for the developing region (z/d=1.6) shows some differences between central and wall regions, these differences indicate that the flow structure at the center evolve differently than at wall of the column, this attributed to bubble-bubble interactions and evolving bubble wake region at wall. while in two bulk regions (z/d=3.2 and z/d=4.8), significant radial differences can be observed in these regions and these differences decreases with increasing gas velocity. if the data are normalized with respect to the center heat transfer coefficients for each axial location as shown in figure 6 a and b, it can be observed that the radial profiles of local average heat transfer coefficients at low superficial gas velocities had lower gradient than those at high superficial gas velocities for all axial locations, this mean the profiles nearly flat in the bubbly flow regime and becomes steeper with churn-turbulent flow regime. this is attributed to different mixing characteristics and resulting different mechanisms in two regimes that it is regarded as one of the most important characteristics of bubble columns (abdulmohsin, 2008). 3.4 comparison with literatures the radial average heat transfer coefficient over cross-section area of the column can be obtained from the radial heat transfer coefficient at different locations as follows: ∫= r rdrrh r h 0 2 )( 1 (3) fig. 7 show a comparison between the heat transfer coefficients measured in this work of a bubble column for fully developed flow regime (z/d=4.8) and reported values under similar operating conditions.( fair,1962) used low velocity range under the same diameter. however, at a superficial gas velocity 0.1m/sec, the agreements were not good. the differences were attributed to the possible differences in the operating regimes, where this study was mainly for the heterogeneous regime, whereas, it was conjectured that, the flow under experimental conditions (of vg) was not fully heterogeneous but prevailing in the transition regime. (hikita., 1981) measured the heat transfer coefficient between the wall of the column and the gas-liquid al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٣٣ dispersion in the bubble column, and they directly used the energy input to calculate the heat transfer coefficients. hence, their results are not considered in following comparison and it was concluded that, the bubble column of immersed heater give heat transfer coefficient values different from that of the wall heating mode. the results in this work and those reported by (verm,1989) and (saxena and co-workers,1994,1989,1990 and 1992) were obtained by assembly immersed cylindrical heaters within column of small diameter (0.108 m), while the column diameter used in this work was 0.45m.therfore, they get results lower than in this work , as reported by (saxena,1992), column diameter can affect the heat transfer coefficients, and the heat transfer coefficients increase with increase in the column diameter in a bubble column without internals. (chen ,2003) used different diameter columns for measurements of heat transfer coefficients with the aid of hot-wire probe and this different technique led to high differences in the results from this work, in addition, they used low range of superficial gas velocity (0.02-0.09 m/s). the results shown in figure 7 are consistent with this finding particularly at high superficial gas velocities, where the column diameter used by (prakash and co-workers , 1997, 1999, 2002) and (wu, 2007) were 0.28 and 0.16 m, respectively. in addition, since prakash and co-workers did not explain the experimental heat flux values used that maybe led to lower heat transfer coefficient relatively specially al low superficial gas velocity. conclusion: local averaged heat transfer measurements are obtained in different regions of twophase bubble column based on constant heat flux fast response probe, over a wide range of superficial gas velocities and large-scale diameter trend to industrial applications. the heat transfer coefficients increasing with increase in the superficial gas velocity, the increase is rapid in the beginning (bubbly flow regime), but slows down as the superficial gas velocity is increased (vertical-spiral regime) and approaches asymptotically to constant values at higher superficial gas velocities (churn-turbulent flow regime), that could be used to identify transition from one flow regime to another. the mechanism of heat transfer processes of a large-scale column elucidate that significant differences were observed between local heat transfer processes in the distributor and bulk regions. axial profiles of heat transfer measurements in the radial direction indicate that the same profiles are reported for bulk and distributor regions, basically the bulk has the highest heat transfer rate in the distributor region, this is attributed to different mixing characteristics and resulting mechanisms in those two regions. the heat transfer al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٣٤ coefficients in the center of the column is greater than near the wall due to the fact that large bubbles collect at center and they are more effective in enhancing heat transfer in the system. this information captures more insight mechanism of heat transfer in the industrial column and could be useful for the optimum design and proper placement of internals for heat transfer in a bubble column reactor. references: 1. abdulmohsin, r., “heat transfer in bubble column operating in churn-turbulent flow regime”, ph.d. thesis, university of technology,baghdad,iraq (2008). 2. chen,w.,hasegawa,t.,tsutsumi,a.,otawara,k., and shigaki,y., “ generalized dynamic modeling of local heat transfer in bubble columns”, chem. eng. journal, 96,37-44 (2003). 3. dhotre, m.t, vitankar, v.s., and joshi, y.b ,“cfd simulations of steady state heat transfer in bubble columns”, chem. eng. journal, 108, 117-125 (2005). 4. fair, j. r., lambright, a. j., and andersen, j. w., “heat transfer and gas holdup in a sparged contactor”, ind. & eng. chem. proc. des. and develop.,1 ,33-36 (1962). 5. hikita, h., asai, s., kikukawa, h., zaike, t., and ohue, m., “heat transfer coefficient in bubble columns”, ind. & eng. chem. proc. des. and develop., 20, 540-545 (1981). 6. li, h., and prakash, a., “heat transfer and hydrodynamics in a three-phase slurry bubble column “ind. eng. chem. res, 36, 4688-4694 (1997). 7. li, h., and prakash, a., “analysis of bubble dynamics and local hydrodynamics based on instantaneous heat transfer measurements in a slurry bubble column” chem. eng. sci., 54,5265-5271(1999). 8. li, h., and prakash, a. "analysis of flow pattern in bubble and slurry bubble columns based on local heat transfer measurements” chem. eng. journal, 86, 269-276 (2002). 9. shaikh, a., and al-dahhan, m. h., “a review on flow regime transition in bubble columns”, intern. jour. of chem. reac. eng., vol. 5, r1 (2007). 10. saxena, s.c, and chen, z. d., “hydrodynamics and heat transfer of baffled and unbaffled slurry bubble columns”, review chemical engineering, 10, 193-400 (1994). 11. saxena, s.c, vadivel, r., and saxena, a. c., “gas holdup and heat transfer from immersed surfaces in two and three phase in bubble columns”, chem. eng. commun., 85, 63-83 (1989). 12. saxena, s.c, rao, n.s, and saxena, a. c., “estimation of heat transfer coefficient for immersed surface in bubble columns involving fine powders”, chem. eng. commun., 63,197-202 (1990). 13. saxena, s.c, rao, n.s, and saxena, a. c., “heat transfer and gas holdup studies in a bubble column: air-water-sand system”, the cana. jour.of chem. eng., 70, 33-41(1992). 14. verma, a. k., (1989) “heat transfer mechanism in bubble columns” the chem. eng. journal, 42, 205-208. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٣٥ 15. wu, c., al-dahhan, m., and prakash, a., “heat transfer coefficients in a high pressure bubble columns”, chem. eng. sci., 62,140-147(2007). fig. 1: schematic diagram of experimental set-up. 1-air filter units 2pressure indicator 3-rotameter system (up to 3.4 m 3 /s) 4plenum 5perforated distributor 6plexiglas bubble column 7thermocouples 8vertical rod type heat transfer probe 9dc power 10amplifier 11daq system 12al: axial location figure 1: schematic diagram of experimental set-up. ������� � �� � �� �� ��� ������� � � ������ ����� �� ��� � �� � ��� ���� ��� figure 2: effect of superficial gas velocity on heat transfer coefficients at different axial locations: (a) in the center of the column (r/r=0), (b) near the wall of the column (r/r=0.9). figure 3: effect of probe locations on local heat transfer coefficients for different radial positions: (a) at high superficial gas velocity (vg =0.35m/s), and (b) at low superficial gas velocity (vg =0.0٣m/s). ������� � �� � �� �� ��� ������� � � ������ ����� �� ��� � �� � ��� ���� ��� figure 4: effect of probe location on normalized heat transfer coefficients for different radial positions: (a) at high superficial gas velocity (vg =0.35m/s), and (b) at low superficial gas velocity (vg =0.0٣m/s). figure 5: radial profiles of local heat transfer coefficients for different axial locations: (a) at high superficial gas velocity (vg =0.35m/s), and (b) at low superficial gas velocity (vg =0.0٣m/s). ������� � �� � �� �� ��� ������� � � ������ ����� �� ��� � �� � ��� ���� ��� figure 6: radial profiles of normalized heat transfer coefficients for different axial locations: (a) at high superficial gas velocity (vg =0.35m/s), and (b) at low superficial gas velocity (vg =0.0٣m/s). figure 7: comparison of heat transfer coefficient with the reported experimental data. article al-qadisiyah journal for engineering sciences 15 (2022) 073–080 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: eng.mec.mas.20.2@qu.edu.iq (hiba k. mohsen) https://doi.org/10.30772/qjes.v15i2.816 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. investigation of laminar forced convection using a different shape of a heat sink hiba k. mohsen* and naseer hamza mechanical engineering department, college of engineering, university of al-qadisiyah , al-diwaniyah, 58001, iraq. a r t i c l e i n f o article history: received 5 may 2022 received in revised form 15 june 2022 accepted 20 july 2022 keywords: heat sink force convection enhancement nusselt number a b s t r a c t improving the thermal design of geometric heat sinks (hss) reduces their size and weight and improves heat dissipation, hence enhancing the speed of electronic devices. in this numerical study, a novel thermal design of hss is proposed by inserting various forms in order to obtain the optimum thermal design for this type of hss. this study has two primary objectives: determining the influence of varying types of hss while maintaining the volume of fins, and introducing new geometries such as circular fin and circular cut fin. the tests were conducted with a heat flux of 11.1 kw/m2 and a reynolds number (re) ranging from 2418.56 to 819.19. for forced convection, three-dimensional numerical simulations utilising the navier–stokes equations laminar model and energy equation are acquired using the commercially available comsol multi-physics version 5.6a cfd software. the results indicate that. a comparison analysis of hss with different geometries revealed that the circular-cut shape exhibited the highest thermal efficiency, as measured by the nusselt number about 153 as well as the heat transfer coefficient and the minimum thermal resistance. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction heat sinks are a sort of heat exchanger that is created and used as a cooling system in electronic equipment such as processing units, and electronic components[1]. several manufacturers have created compact, high-performing electronic devices in response to the modern electronic technology industry's ongoing growth. under the conditions of excessive heat generation and the restrictions placed on the heat transfer area, the operating temperature may rise above the permissible range, which may cause the mechanism of the electronic device to malfunction. the right aircooling system design is essential for ensuring the dependable operation and long lifespan of advanced electronic devices. the impact of geometry parameters on the ideal heat sink conditions has been the subject of numerous research studies in the past. for instance, elmi et al. [2] improved the tapered ratio of a pin fin heat sink (pfhs). it has been demonstrated that changing the fin design significantly impacts heat transfer and pressure drop. furthermore, the overall performance of the pin fin heat sink improves by more than 17% during the optimization process. the heat transmission characteristics of pfhs at various fin types were demonstrated. chingulpitak et al. [3] presented an analysis of the heat transfers and flow processes that occur when airflow is directed through crosscut heat sinks. huang and chen [4],[5] decreased the thermal resistance of the fin array by optimizing the thermal design of non-uniform fin widths of the heat sink. their numerical and experimental results demonstrated that the thermal resistance decrease at re = 5000 was approximately 12.7%, while nu enhanced by approximately 14.5% compared to the original heat sink. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i2.816 https://doi.org/10.30772/qjes.v15i2.816 http://creativecommons.org/licenses/by/4.0/ 74 hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 the effects of the crosscut length, the number of crosscuts, and the re were investigated, and thermal resistance and pressure were measured as a result. an additional feature that was demonstrated was a flow visualization of the air that was contained within the crosscut heat sink. according to what they stated, the optimal ratio of thermal resistance could be achieved if the crosscut length was somewhere between 1.5 and 2.0 mm. the thermal performance of triangular fins, both with and without longitudinal perforations, was significantly improved by shadlaghani et al. [6]. when testing was done, it was discovered that a fin with a triangular cross-section allowed for the greatest amount of convection heat transfer, followed by fins with rectangular and trapezoidal cross-sections. when the height/thickness ratio was increased, triangular fins were able to achieve the highest possible level of heat transfer enhancement. experimentally, nilpueng et al.[7] increased the heat convection of heat sinks made of sinusoidal wavy plate-fins and cross-cut sinusoidal wavy plate-fins. it was found that altering the flow velocity and shift stage facilitated the thermal transition and pressure decline. furthermore, the sinusoidal wavy plate-fin has a greater nusselt number ranging from 5.9 to 19.1%. freegah et al.[8] created a new thermal prototype for plate-fin heat sinks using computational methods. finned heat sinks without fillet, with fillet, with fillet profile by creating symmetrical half-round pins in vertical framework, ribbed half-round pins through perpendicular configuration, symmetrical half-round pins through parallel layout, and corrugated half-round pins through parallel arrangement were investigated. they stated that the decrease in base temperature, as well as thermal resistance of plate-fin heat, sinks with corrugated half-round pins arranged vertically and exposed to flow rate was roughly 25.1% and 29.0%, respectively, especially in comparison to plate-fins with a fillet profile, as well as a 34.48 percent rise in nusselt number. sertkaya et al. [9] conducted an experimental investigation of pin fin, plate, and finless plate heat sinks to optimize free convection heat transfer. the researchers altered the amount, height, distance, and direction of pin fins. it utilized 8 circular shaped pin fins as well as plate heat sinks with pin fin heights of 30 to 45 mm and pin fin diameters of 6 mm with three different directions of 0 °, 90 °and 180 °. the input power varied between 0 and 120 w, and the rayleigh number varied between 1 ×10⁶ and 7 ×10⁶. it was discovered that 121 × 40 pin fin and plate heat sinks increased heat flow at all direction angles. upon determining plate position, upward-facing heat sinks with a 0 °orientation angle value attained the highest heat transfer, whereas bottom heat sinks with a 180 °direction angle value attained the lowest. altun and ziylan [10] investigated the natural convection heat transfer in vertical sinusoidally wavy fins oriented horizontally. in this investigation, the length of the fin was fixed while the configuration of the fin was altered from rectangular to wavy, resulting in a range of new amplitude values. experiments were conducted with wavy fins of three various amplitudes, h/30, h/15, and h/10, and varied heater power sources tend to range from 1.02w to 32.06w. the h/30, h/15, and h/10 values represent the h-values. according to the findings, wavy fins were more effective at improving heat transmission than rectangular fins. however, after a specific wave amplitude value, the increase in amplitude negatively impacts natural convection due to the obstruction of fluid movement because the higher amplitude causes the fluid to move more slowly. feng et al. [11] conducted experimental and analytical research to enhance free convection heat transfer using a new prototype heat sink. a cross-fin heat sink with several long fins and short fins arranged orthogonally was proposed. they discovered that cross-fin heat sinks improved heat transfer characteristics by 15 percent more than plate-fin heat sinks. furthermore, the enhancement was implemented without significantly increasing total volume, material consumption, or expense. pathak et al. [12] numerically analyzed heat sink height's impact on thermal properties. according to the results, the variation of the average nusselt number concerning the flow direction is more significant for nondimensional variable height heat sinks with limited fin spacing and a variable height of 0.25. when comparing fins with finite conductivities of 200 w/m-k and 75 w/m-k to an isothermal fin, the total nusselt number is reduced by 5.7% and 9.5%, respectively. using variable-height heat sinks in conjunction with a reduced fin height of 0.03 m, on the other hand, increases thermal efficiency by 225 percent. moradikazerouni et al. [13] examined the thermal performance of a flat plate heat sink cooled by air through forced convection. the length of the fins was 60 mm, the reynolds number was increased from 3.80 ×10^3 to nomenclature: ahs area of heat sinks (𝑚2) greek symbols dh hydraulic diameter (m)  thermal diffusivity (m2 s-1) kf thermal conductivity of the fluid (w m-1 k-1)  thermal expansion coefficient (k-1) ks thermal conductivity of solid (w m-1 k-1) ρ density hav the average coefficient of heat transfer (w/m².k) μ dynamic viscosity (kg m-1s-1) nu average nusselt number p pressure (kg m-1 s-2) subscripts re reynold number pr prandtl number scfs straight continuous fins ra rayleigh number scspfs straight continuous with square pin fins 𝑇𝑎, mean 𝑇𝑏, mean q the temperature of air (c) base temperature of heat sinks (c) heat transfer rate (watt) spfs square pin fins 𝑃𝑐ℎ u the perimeter of the minimum airflow channel velocity in x-direction (m/s) cfs circular fins v velocity in y-direction (m/s) ccfs circular cut fins z velocity in z-direction (m/s) m˙ mass flow rate (kg/s) hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 75 2.20 ×10^4, and the bottom of the heat sink was provided with 1000 w of power. they discovered that increasing the number and length of fins decreases the surface temperature of the plate by 25% and 20%, respectively. yousfi et al. [14] analyzed the characteristics of forced convection in a pin fin heat sink. they computed the influence of the pyramid ratio on heat transfer and fluid flow characteristics. the reynolds number varied between 8547 and 21367, and the pyramid ratio ranged from 0 to 1. the results indicated that the shape of pyramidal pin fins with a ratio of 1 provided the greatest improvement in hydrothermal performance. tariq et al. [15] studied numerically and experimentally the advantages of plate-fin heat sinks with various perforations and slots. the new design of their flat-fin heat sinks has been determined to increase convection cooling and reduce pressure drop. nusselt numbers for perforations and slots platefin heat sinks were 42.8% and 35.9%, respectively, for re numbers 13049 to 52195. using numerical methods, razavi et al. [16] investigated the effect of heat sinks with splitter pin fins on forced convection. the profit factor's non-dimensional element (j) was calculated to account for both heat resistance and pressure drop effects. when the splitter length to pin diameter ratio l/d was increased, the pressure drop and heat resistance lowered while raising the profit factor. usman et al. [17] carried out experimental research on paraffin wax, rt-44, and used rt-35hc containing triangular geometry heat sinks of 64 pin-fins with volume fractions of 9 percent and pcms of 90 percent. the total heat output ranged from 5 to 8 watts. they reported that the triangular inline pin-fin is the most effective and requires the least amount of cpu. as passive cooling (rt44), pcm yielded the most significant improvement. bahiraei et al. [18] studied a heat sink's hydraulic and thermal performance with mini circular, triangular, and drop-shaped pin fins fabricated using green graphene nanofluid as the coolant. the results indicated that the thermal performance of the circular fins was superior to that of the triangular and drop-shaped pin fins. in addition, the thermal resistance decreased by 3.36 percent as the concentration rose from 0.025 percent to 0.075 percent. in addition, adding nanoparticles to the water did not affect the heat sink's pumping capacity. alhusseny et al. [19] performed numerical research on graphitic foam heat sinks to develop convective heat transfer. the heat sinks were constructed of staggered foam baffles placed perpendicularly or parallel to the coolant stream to reduce pressure loss while maintaining high thermal dissipation. it was discovered that the suggested heat sinks were effective enough to meet high-performance electronics' excessive thermal requirements and could also dissipate heat with acceptable pressure losses. it was indicated that the proper design parameters were applied in consideration of the operating parameters, thereby preventing the formation of any hot zones. jilted et al. [20] presented the thermal performance of a concentric channel heat sink with an alternate slot for fluid flow analytically. four concentric channels width 4 mm, depth 3.5 mm and parallel flow pathways were used to construct the heat sink slot spacing of 3 mm. at the base of the heat sink, a constant heat flux of 50 w and 70 w was applied, and nanoparticles had volume fractions ranging from 0.5 percent to 5 percent, with water as a standard fluid at a flow rate of 30 to 180 ml/min considered. the nanofluidcooled heat sink demonstrated a higher rate of heat rejection than water. the augmentation was 2% for nanofluids with a volume fraction of 0.5 percent and 17% for nanofluids with a volume fraction of 5%. the primary objective of the research is to determine the optimal heat sink geometry to achieve the highest possible cooling performance. in that regard, the comsol version 5.6a multi-physics cfd software was used to investigate five distinct fin geometries, including straight continuous fins (scfs), straight continuous with square pin fins (scspfs), square pin fins (spfs), circular fins (cfs), and circular-cut fins (ccfs). 2. problem description the three-dimensional steady state heat sink shown in fig. 1 was simulated by using comsol multi-physics version 5.6a cfd. pre-processing, solver execution, and post-processing are the three main phases of cfd estimations. during the pre-processing stage, the computational mesh is generated, and the resolved objectives are decided upon. in the second step, configuration, boundary conditions, and numerical models are set to activate the solver. fluid flow characteristics and exhibit geometry are used to define the fins as aluminum. the solver keeps going until the meeting starts. as soon as the solver is complete, the results are examined and the post is prepared. in the analysis, a pc with "11th gen intel(r) core (tm) i7-1165g7 @ 2.80ghz " was used. the force convection heat transfer was attained numerically using a horizontal open-type wind channel. the dimensions of the rectangular channel were 150 mm (width), 200 mm (height), and 800 mm (length) depicted in fig. 2. a) scfs b) scpfs c) spfs d) cfs e) ccfs figure 1 shows cases of study 76 hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 the middle part of the wind channel is contained of the heat sink, to ensure a fully developed flow entering the test section. the heat sink's bottom base is exposed to a constant heat flux. thermal grease was utilised to improve heat transfer conduction between the surface of the plate heater and the bottom surface of the heat sink. the uniform air velocity at the inlet, air temperature of 26 c˚, no-slip boundary conditions, and ambient pressure at the output have all been used. table 1. dimensions of the cases study (mm) figure 2. 3d computational domain the wind channel table 2 the average nusselt number along scfs using different mesh sizes. type of mesh number of nods average nusselt number deviation in percentage extremely coarse 23532 69.84 extra coarse 42855 70.69 1.22% coarser 82216 72.32 2.31% coarse 198995 74.71 3.30% normal 451946 75.56 1.14% fine 1336101 75.64 0.11% finer 3996683 75.81 0.22% the numerical tests are performed on each type to ensure that solutions are independent of grid size based on comparisons of average nusselt numbers as well as average temperature related to heat sinks. table 2 shows, that the optimal mesh for scfs in terms of accuracy and solution time is the normal grid of (451946). in figure. 3. the mesh was bullied along the channel and case study. figure 3. 3d computational quadratic mesh of the domain 3. governing equations the equations of navier-stokes are used as governing the forced convection fluid flow of the system. the following assumptions have been made: 1the working fluid is air. 2the flow is considered as a steady, continuum, fully developed, and three-dimensional. 3the outside sides of the rectangular duct were insulated, except the heat sink base plate, for which a continuous heat flow emulating the electronic heater's heat production was required. 4material characteristics remained unchanged. except for viscosity, fluid characteristics were temperature-independent. 5-flow is considered laminar due to re is less than 2500. 6-negligible radiation heat transfer. 7-the thermophysical properties of air are considered to be constant. for airflow: continuity equation: 𝜕𝑢 𝜕𝑥 + 𝜕𝑣 𝜕𝑦 + 𝜕𝑤 𝜕𝑧 = 0 (1) case study w l h-b h-f s t-f t-p d dh 1.scfs 60 60 6 20.6 12 6 15.17 2. scspfs 60 60 6 20.17 7 6 7 10.66 10.39 3. spfs 60 60 6 33 7.5 6 6 7.5 12.22 case study w l h-b h-f d1 d2 d3 d4 dh 4. cfs 60 60 6 21 60 50 40 30 10 5. ccfs 6 27 60 50 40 30 18 hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 77 xmomentum equation: 𝑢 ∂𝑢 ∂𝑥 + 𝑣 ∂𝑢 ∂𝑦 + 𝑤 ∂𝑢 ∂𝑧 = − 1 𝜌0 ∂𝑝 ∂𝑥 + 𝜗 ( ∂2𝑢 ∂𝑥 2 + ∂2𝑢 ∂𝑦2 + ∂2𝑢 ∂𝑧 2 ) (2) ymomentum equation: 𝑢 ∂𝑣 ∂𝑥 + 𝑣 ∂𝑣 ∂𝑦 + 𝑤 ∂𝑣 ∂𝑧 = − 1 𝜌0 ∂𝑝 ∂𝑦 + 𝜗 ( ∂2 𝑣 ∂𝑥 2 + ∂2𝑣 ∂𝑦2 + ∂2𝑣 ∂𝑧 2 ) (3) zmomentum equation: 𝑢 ∂𝑤 ∂𝑧 + 𝑣 ∂𝑤 ∂𝑦 + 𝑤 ∂𝑤 ∂𝑧 = − 1 𝜌0 ∂𝑝 ∂𝑥 + 𝜗 ( ∂2𝑤 ∂𝑥 2 + ∂2𝑤 ∂𝑦2 + ∂2𝑤 ∂𝑧 2 ) (4) energy equation: 𝑢 ∂𝑇 ∂𝑥 + 𝑣 ∂𝑇 ∂𝑦 + 𝑤 ∂𝑇 ∂𝑧 = 𝐾𝑓 𝜌0𝐶𝑝 ( ∂2𝑇 ∂𝑥 2 + ∂2𝑇 ∂𝑦2 + ∂2𝑇 ∂𝑧 2 ) (5) 3.1 dimensional governing equations in a heat sink 𝐾𝑠 ( ∂2𝑇 ∂𝑥 2 + ∂2𝑇 ∂𝑦2 + ∂2𝑇 ∂𝑧 2 ) + �̇�𝑠 = 0 (6) 3.2 domain and boundary conditions for computation: [21] inlet: 𝑇 = 𝑇𝑖𝑛 = 298 𝐾, 𝑣 = 𝑢 = 𝑤 = 0 outlet: 𝑝 = 𝑝out = 0, 𝑢 = 𝑤 = 0, ∂𝑇 ∂𝑦 = 0 adiabatic walls: 𝑢 = 𝑣 = 𝑤 = 0, ∂𝑇 ∂𝑧 = ∂𝑇 ∂𝑥 = 0 heated wall: 𝑢 = 𝑣 = 𝑤 = 0, 𝑞𝑤 ′′ = −𝑘 ∂𝑇 ∂𝑥 the rate of heat transfer from the heat sink was evaluated using: 𝑄 = 𝑚˙𝑎 𝐶𝑝𝑎(𝑇𝑜𝑢𝑡 − 𝑇𝑖𝑛 ) (7) the overall heat transfer coefficient is determined by: ℎ𝑎𝑣 = 𝑄 𝐴ℎ𝑠(𝑇𝑏 , mean −𝑇𝑎, mean ) (8) the nusselt number can be determined using the following formula: 𝑁𝑢 = ℎ𝑎𝑣𝐷ℎ 𝑘𝑎 (9) where: 𝐷ℎ = 4 𝐴𝑓 𝑃𝑐ℎ (10) the reynolds number can be calculated from: 𝑅𝑒 = 𝜌𝑎 𝑉𝑎𝑣𝐷ℎ 𝜇𝑎 (11) the thermal resistance can be determined from: 𝑅𝑡ℎ = 𝑇𝑏 − 𝑇𝑖𝑛 𝑄 4. results and discussions the present simulation models are first validated with the recent experimental results of nilpueng et al.[1] that studied the effects of pin fin configuration on the thermal performance of plate pin fin heat sinks. they employed a duct that cross-section area of 675mm2 with a total length of 0.8 m. a uniform heat flux of about q″ = 14.81 kw/m2 was applied to the bottom base of the heat sink. while the reynolds number was studied within the range of (1100 to 3000). in this comparison, the heat transfer coefficient is compared with different reynold numbers for scfs as shown in figure 4. as previously stated, the computations have been performed at various reynolds numbers for the five types of hs arrays. furthermore, all of the data were obtained under steady-state settings. figures 5 provides contour plots of the surface temperature distributions for all heat sink shapes examined at 2.4 m/s velocities, and power input (40w). the figure depicts the maximum temperature occurring at the heated bottom wall concerning the heat sink because of the high thermal conductivity of aluminum. the best heat dissipation was substantial between models (d) and (e). the circular fin and circular cut show a good performance in the process of heat dissipation. the reason beyond that is the positive effect of the curvature of these configurations on the flow characteristics hydrodynamically and thermally. the curvature of the circular path of proposed extended surfaces enhances the flow velocity which in its turn increases the reynolds number 78 hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 and thus the nusselt number and consequently increase the rate of heat dissipation, the matter which is examined later throughout this study furthermore, the rapid heat dissipation to the environment due to the increased surface area exposed to air, increasing airflow. 800 900 1000 1100 1200 50 60 70 80 90 100 h e a t tr a n sf e r c o e ff ic ie n t (w /m 2 k ) reynolds number nilpueng et al present study figure 4 comparison the heat transfer coefficient versus re between the current work with those obtained by nilpueng et al[1] at , q= 14.81kw/m2 a) scfs b) scpfs c)spfs d)cfs e)ccfs figure 5. surface temperature gradients for all heat sink geometries at velocity 2.4 m/s, pin= 40w figures 6 provide contour plots of the surface temperature distributions for all heat sink shapes at velocity 1.8m/s, and power input (40w). as a result of a reduction in convective heat transmission, the surface temperature rises. a) scfs b) scpfs c)spfs d)cfs e)ccfs figure 6. surface temperature gradients for all heat sink geometries at velocity 1.8m/s, pin = 40w figure 7. shows the impact of the five shapes of the heat sinks on the nusselt number with varying heat fluxes. the velocity of air is (2.4m/s). as seen in the figure the nusselt number is the maximum value with a circular cut with a gradual increase of the heat fluxes. figure 8. illustrates the relationship between the nusselt number and heat transmission coefficient. when the coefficient of heat transmission increases, the nusselt number rises. ccfs indicate the most outstanding value in comparison to different shapes of heat sinks. figure 9 depicts the effect of mass flow rate on thermal resistance for all investigated hss. this graph demonstrates that flow fragmentation significantly reduces thermal resistance, resulting in enhanced thermal performance. compared to traditional hss, the thermal resistance decreases by roughly 17.53% and 8.02% for cfs and ccfs, respectively, at greater flow rates. inversely proportional to the thermal resistance, the thermal resistance decreases as the flow rate increases (reduced average surface temperature). additionally, ccfs have a lower thermal resistance than other cases for all mass flow rates considered. hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 79 figure 7. distribution of nusselt number with different heat fluxes for all heat sinks figure 8. distribution of nusselt with heat transfer coefficient for all cases study figure 9. distribution of thermal resistance with different mass flow rates for all heat sinks 5. conclusions in this study, numerical simulation was used to improve the thermal performance of the different types of a heat sinks and suggest circular and circular cut fins as a new design in addition to other conventional configurations. simulations have been performed using cfd comsol 5.6 software for reynolds numbers in the hydraulic diameter ranging from 2418 to1591. the obtained results indicate that the circular and circular cut provided the best thermal performance better than the other configurations. in addition, the heat transfer coefficient and nusselt number rise for all heat sink when heat flux and reynolds number increase. furthermore, the average nusselt number was (155, and153) for ccfs and cfs respectively therefore, for each heat sink, the thermal resistance falls as the heat flow and reynolds number rise. the heat sink with a circular cut has the highest heat transfer coefficient and the lowest thermal resistance. references [1] nilpueng, k., et al., effect of pin fin configuration on the thermal performance of plate pin fin heat sinks. case studies in thermal engineering, 2021. 27: p. 101269. [2] ahmadian-elmi, m., et al., a comprehensive study on parametric optimization of the pin-fin heat sink to improve its thermal and hydraulic characteristics. international journal of heat and mass transfer, 2021. 180: p. 121797. [3] chingulpitak, s., et al., experimental and numerical investigations of heat transfer and flow characteristics of cross-cut heat sinks. international journal of heat and mass transfer, 2016. 102: p. 142-153. [4] huang, c.-h. and y.-h. chen, an impingement heat sink module design problem in determining simultaneously the optimal non-uniform fin widths and heights. international journal of heat and mass transfer, 2014. 73: p. 627-633. [5] huang, c.-h. and y.-h. chen, an optimal design problem in determining nonuniform fin heights and widths for an impingement heat sink module. applied thermal engineering, 2014. 63(2): p. 481-494. [6] shadlaghani, a., et al., optimization of triangular fins with/without longitudinal perforate for thermal performance enhancement. journal of mechanical science and technology, 2016. 30(4): p. 1903-1910. [7] nilpueng, k., et al., heat transfer and flow characteristics of the sinusoidal wavy plate-fin heat sink with and without crosscut flow control. international journal of heat and mass transfer, 2019. 137: p. 565-572. [8] freegan, b., et al., cfd analysis of heat transfer enhancement in plate-fin heat sinks with fillet profile: investigation of new designs. thermal science and engineering progress, 2020. 17: p. 100458. [9] sertkaya, a.a., m. ozdemir, and e. canli, effects of pin fin height, spacing and orientation to natural convection heat transfer for inline pin fin and plate heat sinks by experimental investigation. international journal of heat and mass transfer, 2021. 177: p. 121527. [10] altun, a.h. and o. ziylan, experimental investigation of the effects of horizontally oriented vertical sinusoidal wavy fins on heat transfer performance in case of natural convection. international journal of heat and mass transfer, 2019. 139: p. 425-431. [11] feng, s., et al., natural convection in a cross-fin heat sink. applied thermal engineering, 2018. 132: p. 30-37. [12] pathak, k.k., a. giri, and b. das, thermal performance of heat sinks with variable and constant heights: an extended study. international journal of heat and mass transfer, 2020. 146: p. 118916. [13] moradikazerouni, a., et al., investigation of a computer cpu heat sink under laminar forced convection using a structural stability method. international journal of heat and mass transfer, 2019. 134: p. 1218-1226. [14] yousfi, a., d. sahel, and m. mellal, effects of a pyramidal pin fins on cpu heat sink performances. journal of advanced research in fluid mechanics and thermal sciences, 2019. 63(2): p. 260-273. [15] tariq, a., et al., comparative numerical and experimental analysis of thermal 0 20 40 60 80 100 120 140 160 100 110 120 130 140 150 160 n u ss e lt n u m b e r heat flux [kw/m 2 ] scfs scpfs spfs cfs ccfs 100 110 120 130 140 150 150 200 250 300 350 400 h e a t tr a n sf e r c o e ff ic ie n t [w /m 2 .k ] nusselt number scfs scpfs spfs cfs ccfs 0.0002 0.0003 0.0004 0.0005 0.0006 0.0007 0 1 2 3 4 5 t h e r m a l r e si st a n c e [ c 0 /w ] mass flow rate[kg/s] scfs scpfs spfs cfs ccfs 80 hiba k. mohsen and naseer h.hamza /al-qadisiyah journal for engineering sciences 15 (2022) 073–080 and hydraulic performance of improved plate fin heat sinks. applied thermal engineering, 2021. 182: p. 115949. [16] razavi, s., b. osanloo, and r. sajedi, application of splitter plate on the modification of hydro-thermal behavior of ppfhs. applied thermal engineering, 2015. 80: p. 97-108. [17] usman, h., et al., an experimental study of pcm based finned and un-finned heat sinks for passive cooling of electronics. heat and mass transfer, 2018. 54(12): p. 3587-3598. [18] bahiraei, m., et al., cfd analysis of employing a novel ecofriendly nanofluid in a miniature pin fin heat sink for cooling of electronic components: effect of different configurations. advanced powder technology, 2019. 30(11): p. 25032516. [19] alhusseny, a., et al., dissipating the heat generated in high-performance electronics using graphitic foam heat-sinks cooled with a dielectric liquid. international communications in heat and mass transfer, 2021. 127: p. 105478. [20] jilte, r., et al., cooling performance of a novel circulatory flow concentric multichannel heat sink with nanofluids. nanomaterials, 2020. 10(4): p. 647. [21] jaffal, h.m., h.s. jebur, and a.a. hussein, numerical and experimental investigations on the performance characteristics for different shapes pin fin heat sink. ijocaas, 2018. 4(3): p. 330-343. article al-qadisiyah journal for engineering sciences 15 (2022) 038–041 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: dalyashaker1997@gmail.com(dalya shaker qaid) https://doi.org/10.30772/qjes.v15i1.810 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. experimental study of a domestic refrigerator using (sio2/pag oil/r134a) nano-refrigerant as a replacement for pure r-134a dalya shaker qaid* and abbas alwi sakhir department of mechanical engineering, collage of engineering, university of al-qadisiyah, ad-diwaniyah, iraq a r t i c l e i n f o article history: received 13 march 2022 received in revised form ….. 2022 accepted 22 may 2022 keywords: vapor compression refrigeration system sio2 nanoparticels coefficent of performance polyalkylene glycol (pag) r-134a a b s t r a c t this research studies the influence of using sio2 nano-particles of 50nm in a vapor compression refrigeration system (vcrs), along with poly-alkylene glycol (pag) oil and r-134a mixed to create a nano-refrigerant. the methodology used in this work, the nano-particles were performed in three different concentrations (0.1%, 0.3%, and 0.5%) and mixed with 200ml of pag oil. a vcr system was built at the mechanical engineering department laboratory in al-qadisiyah university. in order to study the coefficient of performance (cop) and the consumed energy by the compressor in the two cases of adding the nanoparticles and using a pure refrigerant. the paper showed an increase in the system's cop from 2.3 to 2.81 when using a concentration of 0.5% of sio2/pag oil/r-134a, increasing the refrigeration effect and decreasing the consumed power. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the working fluid of a vapor compression refrigeration system (vcrs) changes from liquid to vapor at the heat absorption section (evaporator) and then back to liquid at the heat rejection section (condenser). the coefficient of performance is the ratio of the heat absorption section's refrigeration effect to the compressor's work input. cop increases by decreasing the compressor's work input or raising the heat removal rate. nano-fluids are a new type of heat transfer fluid that emerged due to fast advancements in nanotechnology. nano-fluids are a unique fluid consisting of a main fluid solution with nano-sized particles (1–100 nm). the nano-fluids are mixes of the base liquid and nanoparticles at particular concentrations. lubricating oil, water, or refrigerant can be used as the main base fluid. cuo, zro₂, sio₂, and other nanoparticles are combined to create a colloid solution known as nano-fluid. nanoparticles have recently been employed in refrigeration systems to increase the cop and dependability of vapor compression refrigeration systems due to their better heat transfer capabilities. it lowered the amount of energy necessary to achieve the cooling effect. k nil achari, and dr.smt.g.prasanthi [1]. 1.1. literature survey kedzierski [2] investigated using (cuo) nanoparticles of 30 nm diameter to 1% and 0.5% volume fractions respectively, suspended in r-134a and polyolester mixture on a roughened horizontal flat surface to compute the boiling performance. the results showed a 0.5% increase in boiling heat transfer. ghorbani et al [3] explored experimentally the effect of adding cuo nano-particles in r600a refrigerant. the work was validated with three different working fluids including: pure r-600a, r-600a-poe oil, and r-600a-oil-cuo with concentrations of 0.5 %, 1 %, and 1.5 %. the results showed an increase in the heat-transfer coefficient by 4.1 %, 8.11 %, and 13.7 %, respectively. senthilkumar and praveen [4] experimentally described the method to energy efficiency of refrigeration retorting system’s improvement that used the r600a refrigerant along with cuo nano particles. according to the findings, when cuo-r600a is used at concentrations of 0.1% and 0.5% and 11.83 and 17.88 % of energy was http://qu.edu.iq/ mailto:dalyashaker1997@gmail.com(dalya https://doi.org/10.30772/qjes.v15i1.810 http://creativecommons.org/licenses/by/4.0/ dalya shaker qaid, and abbas alwi sakhir/al-qadisiyah journal for engineering sciences 15 (2022) 038–041 39 saved, respectively while cuo-r600a had a faster freezing time than the pure r600a. shashikumar and mylsamy [5] investigated the performance of nanoparticles with an equivalent nano particle weight ratio and nanorefrigerant replacement fractions of (0.005, 0.01, 0.015% weight proportion) in a vcrs. r134a, was combined with a variety of copper oxide, titanium oxide, silicon oxide, and aluminum oxide compositions (50nm). as a consequence of this investigation, the consumed power was reduced, and the cop of the system was enhanced (2.656 actual cop at 0.015%). it was found that the use of a nano-refrigerant was both ecologically friendly and safe. kristen bartelt et al [6] investigated the cuo nano-particles to see how they affect the flow-boiling of an (r134a/poe oil) mixture in a plane tube. along with synthetic-ester and copper oxide nano-particles dissolved in the mix at 4% concentration. the heat-transfer coefficient improved by 42 to 82 % when utilizing a nano-lubricant mass fraction of 1% compared to a refrigerant-oil combination that without nanoparticles. when the mass fraction was increased to 2%, the heat-transfer coefficient enhanced by 50% to 101 %. gill et al [7] investigated the energy and exergy characteristic of a household refrigeration system. employing r134a, and the liquefied petroleum gas refrigerants with various oils (polyester, mineral oil, and tio₂, sio₂, and al₂o₃ nanoparticles dispersed in mineral oil). among the evaluated nano-lubricants, the household refrigerator employing lpg refrigerant at 40 g charge with tio2-mo (0.2 g/l tio2) lubricant exhibited the greatest cop and second lowest efficiency (56.32 % and 47.06 %, respectively, greater than r134a/poe). with the least energy and exergy performance analysis of the domestic refrigerator. henderson et al [8] quantified the effect of using nanoparticles like sio₂/cuo on the flow-boiling of pure r134a and r134a/poe-oil mixes throughout mass-fluxes between 100 kg/m²s and 400 kg/m²s. the results showed using sio₂ nanoparticles with r-134a, the heat-transfer coefficient decreased by up to 55 %. when cuo nanoparticles were utilized with an r-134a/polyester mixture, the heat-transfer coefficient rose by 100 %. bandgar et al [9] determined which type of lubricating oil performs best with sio₂ nanoparticles with polyester (poe) oil, and mineral oil in the refrigeration field, at concentrations of 0.5%, 1%, and 1.5%. when a mixture of mineral-oil and 0.5% silica nano-particles were used with r134a refrigerant, resulted an enhancement in the freezing time and a reduction of power consumption by 13.89. nano lubricants can help to save energy while also raising the coefficient of performance (cop) by 12.16 %. the present research studies the possibility of sio₂ nanoparticles to improve vapor compression refrigeration system performance when used at different concentrations (0.1 %, 0.3 %, and 0.5 %) with an r-134a refrigeration gas and pag oil. a nano-refrigerant of sio₂ nanoparticles (50nm) blended with 200ml of refrigeration oil and refrigerant gas was pumped into the system. the goal of this study is to compare the power consumption and coefficient of performance of working with a pure refrigerant vs working with a nano-refrigerant. 2. experimental setup this part deals with the process of construction the vapor compression refrigeration system, preparing, and charging of the nano-lubricant. the main components of the test rig are: table 1. components of test rig figure 1. components of test rig figure 2. vapor compression refrigeration system test rig along with the nano-fluid preparation and charging devices: • mechanical stirrer • ultra-sonic device • nano-fluid injector nomenclature: cpw specific heat of water (j/ kg .k) ei readings input of the energy meter (kwh) cop coefficient of performance ρ density of pure water (g/m³) d diameter of the tank water (m) mw mass of water in the tank (g) h height of the tank water (m) dt temperature difference (c◦) eo readings output of the energy meter (kwh) re refrigeration effect (kj) component details compressor reciprocating compressor with a single-cylinder capacity of 120 w. condenser pipe of 6.35 mm diameter and 8 meters. filter drier capillary tube evaporator evaporator's surface area: 0.152 m² material: copper energy meter pressure gauge two at the inlet (low pressure gauge) and outlet (high pressure gauge) of the compressor. temperature sensor five thermocouples type k sensors for different locations. 40 dalya shaker qaid, and abbas alwi sakhir /al-qadisiyah journal for engineering sciences 15 (2022) 038–041 2.1. nano-fluids preparation and charging method nanoparticles are not immediately injected inside the refrigeration system. instead, they must be thoroughly mixed in the lubricating oil. in general, there are two methods for preparing nanofluids: one-step and two-step procedures. the two-step technique was chosen for this study. in the present case, the lubrication oil was pag oil. sio2 nano-particles were blended with lubricating oil according to refrigerant quantity. stir for 2-3 hours to ensure appropriate mixing of nano-particles with lubricating oil. the nanoparticles are then stabilized in an ultrasonicate and fed into the refrigeration system through a compressor using a nano injector device after thoroughly mixing or completely disseminating in lubricating oil. table 2. thermo-physical properties of sio2 thermo-physical properties sio2 specific heat capacity (j/kg.k) 745 density (kg/m³) 2220 thermal conductivity (w/m.k) 1.4 (a ) (b) (c) figure 3. sio2 / pag oil preparation procedure: a) mechanical stir, b) ultra-sonic device, c) nano-fluid injector 3. results and discussions this part shows the results of the coefficient of performance, power consumption, and refrigeration effect when using different concentrations of nano-refrigerant. compare it with the pure r-134a refrigerant. (a) (b) figure 4.cop and different volume fractions of sio2 nanoparticles when temperature of water inside the evaporator is: (a) 40c◦ ; (b) 50c◦ fig. 4 shows that when using pure r-134a refrigerant with pag oil, cop of the system was 2.3. however with the addition of different concentration of sio2 nanoparticles, the coefficient of performance increases to 2.81 at a concentration of 0.5%. the cop of the system increased by 18.14% at concentration of 0.5%. (a) (b) figure 5. power consumption and different concentrations of sio2 nanoparticles when temperature of water inside the evaporator is: (a) 40c◦; (b) 50c◦ dalya shaker qaid, and abbas alwi sakhir/al-qadisiyah journal for engineering sciences 15 (2022) 038–041 41 fig. 5 shows that when using pure r-134a refrigerant with pag oil, the power consumed by the compressor was 608.69 kj. however with using nano-refrigerant, this value was reduced to 567.22 kj at a concentration 0.5% figure 6. refrigeration effect and different concentrations of sio2 nanoparticles at different temperature of water inside the evaporator fig. 6 shows that when using pure r-134a refrigerant with pag oil, the refrigeration effect was 1850 kj. however, with using nano-refrigerant, it had been increased to 2062 kj at a concentration of 0.5%. 4. equations a. mass of water m= 𝜌.v , g (1) b. volume of water tank v=π/4d² h , mᶟ (2) c. refrigeration effect re=mw cpw dt , kj (3) d. power input to compressor p= (e𝒐-ei).3600 , kj (4) e. coefficient of performance cop= 𝒎𝒘 𝒄𝒑𝒘 𝒅𝑻 (𝑬𝒐−𝑬𝒊).𝟑𝟔𝟎𝟎 (5) 5. conclusion the current work, showed an overall improvement in the vcrs when using different concentrations of sio2/pag oil/r-134a nano-refrigerant, because of the nanoparticles thermo-physical properties. in the present work the size of nanoparticles (sio2) that has been used 50 nm at three concentrations (0.1%, 0.3%, and 0.5%), with three temperatures of water in the evaporator (40c◦, 50c◦, and 60c◦). the observations of this work are the following: 1) increment in the refrigeration effect, where re was 1850 kj in the case of pure refrigerant (r-134a), while increased to 2062 kj at a concentration of 0.5%. the refrigeration effect maximum increase was at concentration of 0.5% by 12.2%. 2) reduction in the consumed power, where it was 608.69 kj in the case of pure refrigerant (r-134a), while decreased to 567.22 kj at a concentration of 0.5%. the consumed power maximum decrease was at concentration of 0.5% by 6.81%. 3) increment in the coefficient of performance, where cop was 2.3 in the case of pure refrigerant (r-134a), while increased to 2.81 at a concentration of 0.5%. the cop maximum increase was at concentration of 0.5% by 18.14%. 6. recommendations the science of nanotechnology is still a new science on the scene, which would greatly increase the efficiency of refrigeration systems. therefore, my advice to the next researcher is to search for new types of nanoparticles in order to use them in the refrigeration system so that there are more and broader studies on the subject. and also to find solutions to the problems of sedimentation and instability in these materials, in order to use the refrigeration system by adding nanomaterials in reality. acknowledgements a special thanks to the department of mechanical engineering at alqadisiyah university, for their help and cooperation in the process of using their laboratories for the experimental works. references [1] k nil achari, and dr.smt.g.prasanthi "performance improvement of vcr system using sio2 nano powder with polyolester oil and mineral oil as lubricant" internation journal for science and advance research in technology, 3.10 (2017): 2395-1052 [2] kedzierski, mark a. "effect of cuo nanoparticle concentration on r134a/lubricant pool-boiling heat transfer." journal of heat transfer 131.4 (2009). [3] ghorbani, babak, et al. "experimental investigation of condensation heat transfer of r600a/poe/cuo nano-refrigerant in flattened tubes." international communications in heat and mass transfer 88 (2017): 236-244. [4] senthilkumara, a., and r. praveenb. "performance analysis of a domestic refrigerator using cuo–r600a nano–refrigerant as working fluid." journal of chemical and pharmaceutical sciences issn 974 (2015): 2115. [5] satheshkumar, g., and k. mylsamy. "withdrawn: exergy analysis for hybrid nano-refrigerants, r134a with al2o3, cuo, tio2 and sio2." (2020): 100043. [6] bartelt, kristen, et al. "flow-boiling of r-134a/poe/cuo nanofluids in a horizontal tube." (2008). [7] gill, jatinder, et al. "energetic and exergetic analysis of a domestic refrigerator system with lpg as a replacement for r134a refrigerant, using poe lubricant and mineral oil based tio2-, sio2-and al2o3-lubricants." international journal of refrigeration 91 (2018): 122-135. [8] henderson, kristen, et al. "flow-boiling heat transfer of r-134a-based nanofluids in a horizontal tube." international journal of heat and mass transfer 53.5-6 (2010): 944-951. [9] bandgar, m. s., k. p. kolhe, and s. s. ragit. "an experimental investigation of vcrs using r134a/poe oil/mineral oil/nano-sio2 as working fluid." journal of emerging technologies and innovative research (jetir) 3 (2016). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٣ developing correlation for prediction of gas holdup using genetic algorithm dr. salih abdul jabbar salih college of engineering al-qadisiya university abstract: this paper deals with the prediction of the overall gas holdup �g in slurry bubble column depending on wide range of databank of around 69 measurements collected from the open literature. correlation for gas holdup was derived using combination of dimensionless analysis and genetic algorithm. the correlation takes in consideration the physical properties of liquid and gas that effect on gas holdup and therefore effect on the design of slurry bubble column. also a comparison between the correlation driven from genetic algorithm and a new correlation driven using quasi-newton method was made and found that the average absolute relative error (aare) was 10.8 % and 16.1%, respectively. this shows that the use of genetic algorithm is improve the prediction of gas holdup in slurry bubble column. key word: genetic algorithm, gas holdup, slurry bubble column. ���� ��� �� ����� ��� ا��! �� ا���زي ������ام ا���ارز��� ا���� � ا��آ��ر #��" ��� ا����ر #��" ��� آ��� ا�% (��)� ا�'�د��� :ا���#� ��� � ا ��� � ��� ا ��ز �� �� � ه�ا ا���� !�"� �g ��� ا ! اغ إ #$ # �+ط ��(" �&�د "'&� �&%ا ا !0/. ذو ا ٦٩" 3&&� �4 �&&4 3&&/'� %>&&3 ا;د�/&&�ت &&9 ا8&& 7 ا�56 � �/&&3 ا'� &&9 @&&+ل <وا6&&3 . ا �&&�� 5&&�ا ا 3&&<+" �4&&� ا �&&a%ل "'&& /3 ا 7%ارز /3 ا c%ر�3 %d /e �/ �� � . و&'" fg&4 #& ��@� ه�ا ا ��� ��k ا(" ��ر ا 7%اص ا !/<��و�&3 '�&�ز وا &�h�i وا � ��� ا ! اغ � ��� ا ��ز ا�� �g fg4 # �!�"� وا �/� ه�ا ا �%ع 9 اa4 �'" m�� �� �0رo&3 �&/9 ه&�ا ا ��&� إ6& اء 4&� . $/ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٤ ��0رo&3 ه&% ه&�x "+>&3 ر��w&/3 وآ�o v&o ��u 3&�/&�د o/&%94 -آ/%8&# 30 � �4 ا �a%ل "'/r �%ا3c8 ا8 m7ام d أ@ و�/9 ���4 ا y ا8 m7ام �a � ا>� ه�cx �30 ا 7%ارز /3 ا c%ر�v'a� �/� 3 ا'" 30� c �mل @�c ا)0&3 %) ١٠.٣� c ا;@& ى 9 ا mىاوه� %). ١٦.١( 3 ��/9/� . ا8 m7ام d �30 ا 7%ارز /3 ا c%ر�3أه symbols used a, b ,c, d, e and z constants. ar archimedes number, ca capillary no., , cs volumetric solid concentration, vol %, db gas bubble diameter, m, eo eotvos number, fr froude number, mo morton number, r the cross-correlation coefficient, re reynolds no., , ug gas velocity, m/s, g ε gas holdup, g ρ gas density, kg/m3, g µ gas viscosity, pa.s, l ρ liquid density, kg/m 3 , l σ liquid surface tension, n/m, l µ liquid viscosity, pa.s, introduction slurry bubble column are widely used in chemical, biochemical, fuel and environmental engineering, and many industries. the use of slurry bubble column in industries is due to their simple construction, low operating cost and high – energy efficiency. major important technology figures prominently in processes for converting natural gas to liquid fuels and light olefins using fisher –tropsch synthesis (albijanic et.al. 2006). bubble columns are an attractive reactors for various multiphase processes, especially for processes involving highly exothermic reactions. these reactors are operated in semi-batched or continuous mode. for this reason, the al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٥ hydrodynamics of such reactors are controlled mainly by the gas flow. overall gas holdup is one of the important parameter for slurry bubble column design and scale up. it is defined as the fraction of the reactor dynamic volume occupied by the gas (mouza et. al. 2005). the behavior of gas holdup has been attributed to many different factors, including the physical properties of gas/liquid/solid phase, gas velocity, and solid loading (shah, 1979). albijanic et. al. (2006), studied the gas holdup in slurry bubble column reactor operated with diluted solution of alcohols and developed a correlation depends on physical properties of liquid such as viscosity and density and surface tension. ruthiya (2005) studied the gas holdup in slurry bubble column especially the influence of particles on gas holdup and found that the rate of decrease of gas holdup with increasing slurry concentration in the heterogeneous regime lower compared to the rate of decrease of gas holdup in the transition regime. mouza et. al.(2005) gave a new correlation based on dimensionless groups(fr, ar and eo) for the prediction of gas holdup in the homogeneous regain. also he found that the viscosity have an influence on bubble coalescence and hinders breakage. also he found that an increasing of surface tension increase bubble formation by promoting breakage and demoting coalescence. shaikh et. al. (2003) studied the gas holdup in slurry bubble column and gave a correlation using artificial neural network to predict the gas holdup using dimensionless groups (re, fr, eo, and mo). the correlation has the lowest aare when they compared to selected correlations. ruzicka et.al. (2003) studied the effect of viscosity on gas holdup, and found that the gas holdup decrease with increasing viscosity. vendu and krishna (2003) studied gas holdup in slurry bubble column for air/ethanol system with three different concentrations. they found that the increasing of solid concentration tends to decrease gas holdup. this decrease due to the increase of coalescence of small bubbles to form larger bubbles. shirsat et. al. (2003) observed that as the effective column height increases, the gas holdup also increases due to the increase in the residence time of the bubbles in the contactor. michele et. al. (2000) used cfd method to predict gas holdup depending on superficial gas velocity solid loading and sparger geometry. deswart et.al. (1996) studied the hydrodynamics of slurry bubble columns, and found that increasing slurry concentration reduces the total gas holdup and this reduction is to be largely attributed to the destruction of the small bubble population which have bubble diameters smallest than 10 mm. increasing slurry concentration increases the size and distribution of the large bubbles. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٦ artificial techniques brought a new sight to the characterization of gas holdup in slurry bubble column. to the best of our knowledge, the pioneer of the use of these techniques is shaikh et.al.(2003) and behkish (2004), both authors used back propagation neural network for prediction of gas holdup. however, correlations still keep the lock of experimental data. proper functions require significant computational effort when they are nonlinear and involve large number of parameters. for this reason, genetic algorithms bring efficient solutions by avoiding local minima. moreover, it improves the robustness toward the uncertainties on the correlation coefficients, due to their adaptive and stochastic aspects. the main object of this study is to predicate the gas holdup using the genetic algorithm techniques which is done using statistica 7 from statsoft, inc., and a comparison between the above correlation and another correlation done using another method (quasinewton) was done. genetic algorithms genetic algorithm is a particular class of evolutionary algorithms, which are adaptive search techniques for approximating solutions of optimization and prediction problems. they are based on a biological metaphor which simulates processes in natural systems that are necessary for evolution, specifically those that follow the principles first proposed by charles darwin of the survival of the fittest. as such, they represent an intelligent exploitation of a random search within a defined search space to solve a problem. a population of abstract representations (chromosomes) of solution candidates (individuals) for an optimization problem evolves toward better solutions. traditionally, solutions are represented in binary systems as an array of bits, but different encodings are also possible, such as integer or real encodings. the evolution begins from a population of completely random individuals (initialization) and happens in generations. in each generation, the fitness of the whole population is evaluated. multiple individuals are stochastically selected (selection) from the current population according to their fitness, and mutated (mutation) or recombined (crossover) to form a new population (reproduction). the latter is then used in the next iteration. the algorithm stops when a solution is found satisfying minimum criteria or when a fixed number of iterations are reached. when applying genetic algorithm, one has to define at least a genetic representation of the solution domain (encoding) and at the same time a fitness function to evaluate the defined solution domain. in other words, al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٧ one needs to fix the encoding of the solution as an array of bits, integers or floats in such a way that their parts are easily aligned due to their fixed size. besides, at the encoding stage, one has to take into account the crossover and mutation operator complexity, which depends on the solution representation. indeed, in some situations, in addition to problems associated with encoding and with evaluation definitions, one can face the problem of the definition of crossover and mutation operators in order to keep the validity of the solution. furthermore, the fitness function has to be defined over the genetic representation in order to measure the quality of the represented solution. the fitness function is always problem dependent (melanie, 1998). once the genetic representation of the solution is known and the corresponding fitness function is defined, the genetic algorithm starts initializing a population of solutions randomly. then the algorithm improves it by repetitive applications of crossover, mutation and selection operators figure (1). 1. collection of data a set of 69 experimental data of different systems were collected from literatures for different workers. the data collected for slurry bubble column reactor operated with different liquids and different slurry concentration. table (1) summarizes the sources of data. the physical properties such as density, surface tension and viscosity were included in the data base. most of slurry bubble column are operated with low liquid velocities, which have been reported to have little or no effect on over all gas holdup (shetty et. al. 1992), so it is not included in the correlation. 2. dimensionless groups most of workers on slurry bubble column reactors predicted the gas holdup using correlations based on dimensionless groups. the following criteria guide was used to choose the input dimensionless groups: a. the dimensionless groups should be as few as possible. b. each group should be highly cross-correlated to the output parameter. c. the input groups should be weakly cross-correlated to each other. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٨ so in this study reynolds number, densities of gas to liquid ratio, viscosities of gas to liquid ratio, volumetric solid concentration, and finally the capillary number (which were used by (hikita et. al., 1988) and (zou et. al., 1988)), where used to predict gas holdup in our work. 3. statistical analysis the statistical analysis of prediction results is based on the following criteria: a. the average absolute relative error (arre) should be minimum. ∑ − = n pred y yy n aare 1 .exp .exp.1 1 b. the cross-correlation coefficient, r between input and output should be around unity. ( ) ( ) ( ) ( )∑∑ ∑ −− −−− = n meanpredpred n mean n meanpredpredmean yyyy yyyy r 1 2 ).(. 1 2 ).(exp.exp 1 ).(.).(exp.exp 2 results and desiccation a. gas holdup prediction using genetic algorithm using the statistica neural network 7 (snn) a correlation has been developed to predicate the gas holdup by applying the 69 experimental data point collected (section 4), putting the population at 100, generations at 100 and mutation rate at 0.1 as shown in figure (2). table (2) shows the minimum and maximum of dimensionless groups used. table (3) shows the model summary used to predict the gas holdup using snn. the final predicted gas holdup has been drawn against the experimental gas holdup figure (3). b. gas holdup prediction using quasinewton method using the statistica 99 and quasi-newton method (qn) a correlation has developed to predicate the gas holdup by applying the 69 experimental data point collected using the following form: ze d l g c l gb g a cacvre ++      +      ++= µ µ ρ ρ ε 3 the result from the program is shown below table (4). al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤١٩ the equation 3 will be: 015.00189.0 189.0168.0 0837.0 cacvre09.6 −− − ++      +      ++−= l g l g g µ µ ρ ρ ε 4 figure (4) shows the relation between the experimental and predicated gas holdup using the qn method. comparing between the correlations obtained using snn and qn are shown in figure (5), which leads to conclude that genetic algorithm is more accurate than quasi-newton method. moreover the comparing between these correlations on statistical analysis basis leads to above the conclusions. table (5) shows the mentioned comparing. conclusions in this paper, a new presentation of predicating gas holdup in slurry bubble column was made using genetic algorithm and this correlation was compared with a correlation obtained using quasi-newton method. this comparing leads to one conclusion that using genetic algorithm is better than using of empirical correlations by means of results of statistical analysis done her. this work identified reynolds number, gas to liquid densities ratio, gas to liquid viscosities ratio, volumetric solid concentration and capillary number as expressive dimensionless groups to predicate the gas holdup in slurry bubble columns. hence the developed genetic algorithm correlation should be useful in the scale up of slurry bubble columns. references • albijanic b.c, duric m, ptrovic l. d, and tekic m. "prediction of gas holdup for alcohol solutions in a draft tube bubble column", apteff, 2006, 37, 71-82. • behkish a., (2004), “hydrodynamic and mass transfer parameters in large-scale slurry bubble column reactor “, phd thesis, university of pittsburgh. • de swart j.w., van vliet r.e., and krishna r. " size, structure and dynamics of large bubbles in two dimensional slurry bubble column", chem. eng. sci., 1996, 51, 20, 4619-4629. • hikita, h, asal s., tanigawa k., segawa k., and kitao m., "gas holdup in bubble column" chem. eng. journal, 1980, 20, 59-67, cited from (albijanic 2006). • koop k., vendu c.o., and krishna r. "large bubble sizes and velocities in a bubble column slurry reactor", chem. eng, technol., 2004, 27, no. 11, 1195-1199. • melanie m, "an introduction to genetic algorithm s", a brad ford books, 1998. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٠ • mouza a.a., dalakoglou g.k, and paras. s.v. (2005) “effect of liquid properties on the performance of bubble column reactors with fine pore spargers” chem. eng. sci., 60, 1465 – 1475. • ruthiya, k. c. (2005) “mass transfer and hydrodynamics in catalytic slurry reactors” phd thesis, technische university of eindhoven. • ruzick m.c., drahos j., mena p.c. and teixeira j.a. " effect of viscosity on homogenous –heterogeneousflow regime transition in bubble columns", chem. eng. journal, 2003, 96, 15-22. • shah y. t., godbole "gas –liquid –solid reactor design ", mc-grow hill, new york, 1979. • shaikh a., al-dahhan m. (2003) “development of an artificial neural network correlation for prediction of overall gas holdup in bubble column reactors” chem. eng. and processing, 42, 599-/610. • shirsat s., mndal a., kundu g., and mukherjee d. "hydrodynamic studies on gas liquid down flow bubble column with non newtonian liquids", ie(i) journal, 2003, 37, 39-43. • vandu c. o. and krishna r. (2003) “gas hold up and volumetric mass transfer coefficient in a slurry bubble column “ chem. eng. techno., 26, no. 7, 779-782. • zou r., jiang x., li b, zu y. and zhang l. "studies on gas holdup in bubble column operated at elevated temperature", ind. eng.& chem. res., 27, 1988, 1910-1916, cited from (albijanic 2006). table (1) data sources of experimental points no. reference system no. of exp. 1 koop et.al. (2004) air/paraffin oil/alumina catalyst 43 2 vendu and krishna (2003) air/ethanol/raney cobalt catalyst 26 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢١ table (2) maximum and minimum for dimensionless groups. variable reynolds no. density ratio viscosity ratio volumetric solid concentration capillary no. gas holdup maximum 2.485 0.002 0.013 0.25 3469.56 0.229 minimum 0.016 0.0016 0.002 0.01 25.03 0.014 mean 0.8293 0.0017 0.0061 0.0996 640.8 0.1025 table (3) model summary of genetic algorithm. profile train error input hidden (1) hidden (2) output 5:5-6-1:1 0.02965 5 6 0 1 table (4) the result of using qn method. parameter a b c d e z estimated -6.09 0.0837 -0.168 0.189 -0.0189 -0.015 table (5) comparing between snn & qn methods. correlations aare % r snn 10.8 0.988 qn 16.1 0.977 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٢ figure (1), genetic algorithm block diagram figure (2), dialog box used in snn. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٣ gas holdup exp. 0.00 0.05 0.10 0.15 0.20 0.25 g a s h o ld u p p re d . 0.00 0.05 0.10 0.15 0.20 0.25 figure (3), experimental gas holdup verses predicated gas holdup using snn. gas holdup exp. 0.00 0.05 0.10 0.15 0.20 0.25 g a s h o ld u p p re d . 0.00 0.05 0.10 0.15 0.20 0.25 figure (4), experimental gas holdup verses predicated gas holdup using qn al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٢٤ gas holdup exp. 0.00 0.05 0.10 0.15 0.20 0.25 g a s h o ld u p p re d . 0.00 0.05 0.10 0.15 0.20 0.25 gas holdup (exp.) vs gas holdup (pred.)snn gas holdup (exp.) vs gas holdup (pred.) q.n plot 1 regr figure (5), experimental gas holdup verses predicated gas holdup using snn & qn. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 1 optimal selection of heat transfer surfaces for plate-fin heat exchangers ass. proff. dr. abbas a. s. aljeebori college of engineering-al-qadisiyia university mech. dep. abstract the surface selection method is the performance evaluation criteria (pec) to reach an optimum surface selection. the method is not limited to surfaces found in the literature, but will accommodate any type of the heat transfer surfaces. the capability is demonstrated by the surface of selection of gas /gas plate-fin heat exchanger. a general methodology for plate-fin heat exchangers surface selection has been shown and applied for a specific illustration problems. the objective of the present work can be summarized as the selection of the plate-fin surfaces (high performance surfaces) depending on the qualitative and quantitive consideration for low re. keyword: heat exchangers, compact, surfaces, fins, optimization. زعنفة الحرارية-االختيار األمثل لسطوح انتقال الحرارة لمبادالت صفيحة عباس علوي الجبوري. د.م.أ جامعة القادسية-آلية الهندسة الخالصة هذه الطريقة . إن طريقة االختيار المثلى لسطوح انتقال الحرارة في هذا البحث هي طريقة تقييم األداء للوصول إلى امثل اختيار تم تطبيق هذة الطريقة على اختيار سطوح . بل هي مالئمة لكل سطوح انتقال الحرارة, محددة بالسطوح الموجودة بالبحث فحسبغير هذا . آذلك تم عرض أسلوب وطريقة االختيار المثلى بمسائل توضيحية. زعنفة-غاز الحراري ذو الصفيحة-انتقال الحرارة لمبادل غاز .زعنفة الحرارية-لكمية والنوعية للوصول لالختيار األمثل للسطوح الحرارية لمبادالت الصفيحةالبحث يعتمد على االعتبارات ا nomenclature a : total heat transfer area, 2m fra : frontal or face area on one side of the exchanger, 2m fa : fin or extended surface on one side of the exchanger, 2m 0a : minimum free flow area on one side of the exchanger, 2m b : distance between two plates (fin height)in a plate-fin exchanger, m c : flow stream heat capacity rate, cwcm op , . al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 2 pc : specific heat of fluid at constant pressure, j/kg. c o hd : hydraulic diameter of flow passages, 4 maloa , stde : pumping power per unit of heat transfer surface area f : fanning friction factor, dimensionless g : exchanger flow-stream mass velocity, smk g ./ 2 h : heat transfer coefficient, cmw o./ 2 j : colburn factor, st 3 2 pr , dimensionless l : fluid flow (core) length on one side of the exchanger, m . m : fluid mass flow rate, , skg / ntu : number of heat transfer units, dimensionless pr : prandtl number, dimensionless q : heat transfer, w re : reynolds number, dimensionless p : pimping power, w p : pressure, 2mn fp : fin pitch, mm st : stanton number, pgch / , dimensionless α : ratio of free-flow area to the frontal area β : ratio of total heat transfer area on one side of a plate-fin heat exchanger to the volume between the plates on that side 0η : total surface effectiveness µ : viscosity coefficient, pa.s ρ : density, 3/ mkg p∆ : pressure drop, pa δ : fin thickness, mm subscripts f : fin max : maximum min : minimum t : triangular r : rectangular s : reference surface in performance evaluation criteria (pec) std : standard temperature and pressure al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 3 introduction a proper selection of surface is one of the most important considerations in plate-fin heat exchanger design. there is no such thing as surface that is best for all applications. the particular application strongly influences the selection of the surface to be used. the objective of the system in which the heat exchanger is to be used also influences the surface selection. both qualitative and quantitative considerations will be presented for surface selection. comprehensive heat exchanger optimization is a formidable task, complicated by many qualitative and quantitive considerations affecting the selection of a surface pattern (shah, 1978). the heat exchanger in the present work represents a one type of the plate-fin heat exchangers. the design of a plate-fin heat exchanger is a complex task requiring the examination and optimization of a wide variety of heat transfer surfaces. studies have shown that a poor choice of either the heat transfer surfaces or design parameters can be more than double the costs chargeable to a heat exchanger . the selection method, in the present study, is based on the performance evaluation criteria (pec) of webb (1981). the qualitative considerations for surface selection are the operating temperatures, pressure, fluid contamination, cost, maintenance, and ruggedness. the problem of heat exchanger design is very intricate. because of a large number of qualitative judgments, trade-offs and compromises, the heat exchanger design is more of an art at this stage. in general, no two engineers will come up with the same heat exchanger design for a given application. most probably a “better” design will be arrived at experienced engineer. somewhat arbitrarily, a plate-fin surface will be specified that has an area density β greater than 700 m2/m3 (shah, 1983). the uniqueness of plate-fin and enhanced exchangers are: (1) many surfaces available having different orders of magnitude of surface area density; (2) flexibility in distributing the area on the hot and cold sides as desired by design considerations; and (3) generally substantial cost, weight, or volume savings (shah and webb, 1983). fins are attached to the plates by mechanical fit, gluing, soldering, welding, or extrusion. in the automotive industry, fins in the plate-fin heat exchangers unit is referred to as centers in order to distinguish them from fins outside of the tubes in a tubefin exchanger. the latter are simply referred to as fins. fins used in a plate-fin heat exchangers exchanger are categorized as follows: (1) plain (uncut surfaces) and straight fins; (2) plain but wavy fins; and (3) interrupted fins such as strip, louver and perforated fins. the velocity and temperature boundary layers thicken on plain surfaces resulting in both a lower heat transfer coefficient and lower friction factor. plain fins are used when the pressure drop is critical and interrupted or wavy fins cannot meet the pressure drop requirement together with a flow area constraint. plain fins are made such that the flow passages have triangular, rectangular or other noncircular shapes. when the plain fin is formed such that it has a wavy surface in the flow direction, the boundary layers are either thinned or interrupted when the flow is turned resulting in both higher heat transfer coefficient and a higher friction factor. boundary layers can be more completely discontinuous. examples are strip fins, and perforated fins. strip fins are also referred to as also offset– fins, lance– offset fins, serrated fins or segmented fins (shah, 1981b). specific qualitative considerations for platefin surfaces (shah, 1983). a number of heatexchanger design methods have been proposed to determine the heat exchanger design. bergles et al. (1974) performed an evaluation of different objective functions for plate-fin heat exchangers with different heattransfer surfaces, but with the same specifications. the method did not include any actual optimization techniques, but results did show that a great improvement in heat exchanger performance could be made by proper selection of design parameters. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 4 quantitative selection surface selection is made by comparing performance of various heat exchanger surfaces and choosing the best under some specified criteria for a given heat exchanger application. the performance evaluation criteria used in the comparison were those recommended by shah (1978). these criteria all required the j factor, friction factor f, and reynolds number, together with the geometry specification. where the gasside properties were required at a standard temperature and pressure, these were taken to be for dry air at co25 and 1.01325 bar, respectively. the ratio of j factor to the friction factor, against reynolds number, generally known as the “flow area goodness factor,” suggested by london (1964), where ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ ∆ ν α = p mtu fj 2 pr1 2. 2 0 3 2 (1) where mincuatu =ν the standardized heat transfer coefficient against the pumping power per unit of heat transfer surface area suggested by london and ferguson (1949), where 3 2 pr re , stdh stdpstd std d cj h ⋅ ⋅⋅⋅ = µ (2) and 32 33 2 re hstd std std d f ⋅⋅ ⋅⋅ =ε ρ µ (3) the performance of the heat exchanger per unit volume, the criteria suggested by shah (1978). this method includes the effect of the fin effectiveness, which is an important factor in heat exchanger evaluation. a good performance-using criterion gives the best heat exchanger to use where the size of the unit is an important consideration. 2 , 3 2 pr 4re hstd stdpo stdo d cj h std ⋅ ⋅⋅⋅⋅⋅⋅ =⋅⋅ µησ βη (4) and 42 33 2 4re hstd std std d f ⋅⋅ ⋅⋅⋅⋅ =⋅ε ρ µσ β (5) for a given pec, the ratio of the design objective for surface of interest to a reference is then calculated as function of a similar ratio of a design variable. equationds (6) and (2.7) are the generalized equations necessary for calculation of the performance improvement afforded by the enhanced surface. 3 ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ α α ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = ssss g g f f p p (6) 3 1 2 1 ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⋅⋅ = α α sss s ss a a p p f f st stu u (7) the advantage of this comparison method for plat-fin heat exchangers are: (1) the designer can select his own criteria for comparison; (2) he can then compare performance of a surface to that of a al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 5 reference surface directly; and (3) he does not need to evaluate the fluid properties since they drop out in computing the performance ratios. however, the performance comparison is considered only for one side of a compact heat exchanger. surfaces on each side of an exchanger may be selected by one of the methods of the preceding section. when such surfaces are incorporated in a heat exchanger, the resultant exchanger may not be optimum since criteria other than those related to j and f may play an important role. for example, in addition to prescribed heat transfer and pressure drop, the core frontal area may have been restricted on one side of the exchanger. if the surface selected by one of the proceeding methods requires larger than specified frontal area, it will not meet the design specifications and hence it will not be considered in the final selection (shah, 1983). in general heat exchangers are designed for many varied applications, and hence may involve many different performance criteria. some of these criteria may be minimum initial and operating costs, minimum weight or material, minimum volume or heat transfer surface area, minimum mean temperature difference, maximum heat transfer rate, and so on. when a single performance measure has been defined qualitatively and is to be minimized or maximized, it is called an “objective function” in design optimization. a particular design also be subjected to certain requirements such as required heat transfer, allowable pressure drop, limitation on height, width and/or length of the exchanger, and so on these requirements are called “constraints” in a design optimization. method of optimal selection we can use the tables for the surface parameters such as tables in kays and london(1964). if the parameters were not found in the literature we can use the following procedure: using the nomenclature of fig. 1 perimeterwetted areaflow dh 4 = (8) )()( )((2 δδ δδ −+− −− = f f h pb bp d (for plain rectangular fin) (9) ( )( ) ( ) ( ) θ δ δ δδ sin 2 − +− −− = b p bp d f f h (for triangular fin) (9a) ))(( ))(( bp bp areafrontal areaflow f f f δ δδ σ + −− == (for plain rectangular fin) (10) ( )( ) ( )( )bp bp f f f δδ σ −− = (for triangular fin) (10a) hd σ β 4 = (11) re 3 =j , re 14 =f (for plain rectangular fin)(shah and london, 1978) (11a) 3 2 pr /. − = p h gc dknu j , 439.4=nu , re 233.18 =f (for triangular fin ) (11b) also we will derive two cases( case 1 and case 6) only to illustrate the procedure. the other criteria derived by the same procedure. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 6 we will use the following optimization cases according to the aims of a customer case1: max q subject to 1 , = sfr fr a a , 1= sl l , 1 . . = sm m , 1 re re = s , 1> sp p , 1> sq q , 1= ∆ ∆ is i t t ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ssss g g a a f f p p (12) since ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ sg g = 1 re re =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ s (given), eq. (12) becomes ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ fs f f p p (13) ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ss s sss ph ff ph ph a a / / / / 0 0 (14) ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ sss q q ah ha (15) since same heat transfer area eq. (15) becomes ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ss q q h h (16) eq. (14) becomes ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ s s ss ff jj p p h h / / (17) consolidating eqs. (13), (16), and (17) yields ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ sss j j h h q q (18) case2: min it∆ subject to 1 , = sfr fr a a , 1= sl l , 1 . . = sm m , 1 re re = s , 1= sp p , 1= sq q , 1< ∆ ∆ is i t t , yields ( ) s s is i jj ff t t 3 1 = ∆ ∆ case3: max q subject to 1 , = sfr fr a a , 1= sl l , 1 . . < sm m , 1 re re < s , 1= sp p , 1> sq q , 1= ∆ ∆ is i t t , yields ( ) 31 re re −==⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ s ss ff w w , 2− ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ss s s w w ff jj q q case4: min it∆ subject to al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 7 1 , = sfr fr a a , 1= sl l , 1 . . < sm m , 1 re re < s , 1= sp p , 1> sq q , 1= ∆ ∆ is i t t , yields 3 1 re re − ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ == sss f f w w , ( ) ( )s s is i jj ff t t 3 1 = ∆ ∆ case5: min p subject to 1 , = sfr fr a a , 1= sl l , 1 . . < sm m , 1 re re < s , 1< sp p , 1= sq q , 1= ∆ ∆ is i t t , yields ( ) ( )s s s ff jj p p 3 = , 2 1 2 1 re re ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ == s s sss ff jj p p w w case6: min l subject to 1 , = sfr fr a a , 1< sl l , 1 . . < sm m , 1 re re < s , 1= sp p , 1= sq q , 1= ∆ ∆ is i t t using eq. (6) with the constraint of case 6 yields 3 1 ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sss g g a a f f then 3 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ g g f f a a ss s (19a) ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎟ ⎠ ⎞ ⎜⎜ ⎜ ⎝ ⎛ = s s jj ff m m / / 1 2 . . (19b) then 2/1 . . / / ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = ⎟⎟ ⎟ ⎠ ⎞ ⎜⎜ ⎜ ⎝ ⎛ s s s ff jj m m (20) s s ss a a v v l l . β β == (21) eqs. (19), (20), and (21) represents the performance evaluation criteria for the case 6, which used for any plate-fin surfaces(fins). case7: min l subject to 1 , = sfr fr a a , 1< sl l , 1 . . < sm m , 1 re re = s , 1< sp p , 1= sq q , 1= ∆ ∆ is i t t , yields ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ s s s jj ff p p , ( ) ( )s s s ff pp a a = , 1− ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sss a a l l β β al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 8 case8: min p subject to 1 , = sfr fr a a , 1< sl l , 1 . . = sm m , 1 re re = s , 1< sp p , 1= sq q , 1= ∆ ∆ is i t t , ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sjj sff sp p , ( )( ) 1−= ss s ffpp a a , 1− ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sss a a l l β β case9: min a subject to 1 , > sfr fr a a , 1< sl l , 1 . . < sm m , 1 re re < s , 1< sp p , 1= sq q , 1> ∆ ∆ is i t t , yields 2 1 ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = s s os o jj ff a a , ( ) ( ) 23 2 1 s s s jj ff a a = , 2 1 re re ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = s s s ff jj case10: max q subject to 1 , > sfr fr a a , 1< sl l , 1 . . = sm m , 1 re re < s , 1= sp p , 1= sq q , 1= ∆ ∆ is i t t , yields ( ) ( ) 21 2 3 s s s ff jj a a =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ , ( ) ( ) 3131 re re −−= ss s aaff , 1 re re − ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sos o a a , ( ) ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = s s oso s ff jj aa q q 2 , 1− ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sss a a l l β β case11: min it∆ subject to 1 , > sfr fr a a , 1< sl l , 1 . . = sm m , 1 re re < s , 1= sp p , 1= sq q , 1< ∆ ∆ is i t t , yields 2 1 ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ s s os o jj ff a a , ( ) ( )soso s ffaa a a 3= , ( ) ( ) ( ) 13132 −= ∆ ∆ sss is i jjffaa t t , 1− ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = sss a a l l β β case12: min p subject to 1 , > sfr fr a a , 1< sl l , 1 . . = sm m , 1 re re < s , 1< sp p , 1= sq q , 1= ∆ ∆ is i t t , ( ) ( ) 22 −= ss s jjff a a , ( ) ( ) ( ) 213 −−= sss s aaffjj p p , ( ) 21 2 1 − ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = s s s os o pp jj ff a a , 1 re re − ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = os o s a a al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 9 results and discussions in the present work, the air/air will be taken for the plate-fin heat exchanger. hence the objective function for pec at gas side is to minimize the pumping power. but, the objective function for the air side is to minimize the heat transfer area for the same heat recovery. however, the selection procedure will be illustrated by a specific examples for each side. 1-air-side surface selection offset strip fin (osf)and plain fins for the air side to be compared as a reference and augmented surfaces. the two surfaces to compared are the surface 101 (london and shah, 1968)as shown in table(1), and the surface 10-27 (kays and london, 1964)as shown in table(2). the case 9 was chosen is which minimizing the surface area. the flow cross-sectional area required to obtain ha for operation at fixed friction power (p) and flow ( . m ) is given by, see eq. (1) j f c mha a p o ρ2 pr 2. 2 3 2 = (22) by setting 1== sss ppahha for smm .. =1, eq. (22) may be written in the nondimensional form s ss os o jj ff g g a a ==⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ 2 22 (23) equation (23) defines the ratio of mass velocities required to satisfy the constraints for case 9. saa ratio is calculated from eq. (6) as follow ( ) ( ) ( ) 23 2 1 s s s jj ff aa = (24) before applying these equations, the surface 101 must be scaled to give same hd of the plain-fin surface. surface 101 (london and shah, 1968) represents osf surfaces, and surface 10-27 (kays and london, 1964) represents the plain fin surfaces. after scaling the dimensions, which is found, the following geometries for the surface 101 will be obtained: b=12.2 mm, hd =3.51 mm, δ =0.2mm , β =1024 m 2/m3 , and fσ =0.889 the plain fin surface is assumed to operate at re = 900. since both geometries have the same hd , (res /re) 2 is given by eq. (23). using the j and f vs re data, see table(1), for both surfaces. eq. (23) will be solved as follow. 1623.1 0074.001535.0 0253.0061.0 re re 2 ===⎟ ⎠ ⎞ ⎜ ⎝ ⎛ s ss jj ff then 078.1 re re =⎟ ⎠ ⎞ ⎜ ⎝ ⎛ s where the reference surfaces s is the plain fin surface. then, by evaluating eq. (23) for sre =900 and re =834.88 we obtain 49.0=⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ sa a , ( ) 5.0 1003 1024 49.0 =⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ==⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ β βs ss a a v v using eq. (4) yields al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 10 f sf os o sfos fo sfr fr a a a a a a σ σ σ σ , ,, ⋅== , g g gm gm a a s s os o == . . then f sfs sfr fr g g a a σ σ , , ⋅= 1.1 88.0 899.0 078.1 =⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = sfr fr a a , therefore, the offset strip-fin will provide ha as the plain fin using 51% less surface area but will require 10% greater flow frontal area ( frα ) to satisfy 1 .. == ss mmpp constraints. 2gas-side surface selection by the qualitative criteria, the following surfaces has been selected: the triangular and rectangular plain fins for the gas side. one of the two surfaces will be a reference surface, and the other must be as an augmented surface for pec. this example will be presented using case 8, which use to minimize the pumping power. two plain fin geometries having the same fin pitch are compared: a triangular geometry (t) and a rectangular ( )r with 0.2 mm fin pitch, 8 mm plate spacing, and 0.2 mm fin thickness. the case 9 constrains the two geometries to operate at the same mass flow rate with equal frontal velocity and ha values. since the velocities are known, the j and f values are directly calculable. the calculations are made for air flow at co25 and 4 m/sec frontal velocity. the j factor is given by fully developed laminar solution for constant wall temperature. after scaling the triangular fin dimension to give the same hd of the rectangular fin we obtain the following dimension using the calculated j and f values we obtain ∗ 24.1 00646.0004.0 024.00185.0 ==⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ =⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ rt rt r t s jj ff p p p p , ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ==⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ f f p p a a a a s sr t s ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ = t r r t f f p p ( ) 6.1 0185.0 024.0 24.1 =⎟ ⎠ ⎞ ⎜ ⎝ ⎛= then, for the same frontal area, flow area, and heat transfer rate, case 9 shows that the triangular geometry requires 60% more surface area and 24% greater pumping power. fig. 2 shows the results of the 12 cases of pec for the triangular and rectangular fins basing on the results of previous section. thermophysical properties for the air is calculated at kt 298= and smu m /4= . fig. 2a represent the temperature difference ratio w.r.t. the previous 12 cases. from the above figure case 10 represent the best case for selection to increase the inlet temperature difference for plate-fin heat exchanger. fig. 2b represents the mass flow rate ratio w.r.t. cases. from the above figure case 5 represent the best case for the surface selection. fig. 2c represents the re ratio w.r.t. cases. from the above figure case 5 represent the best case for the surface selection. fig. 2d represents the pumping power ratio w.r.t. cases. from the above figure case 5 represent the best case for the surface selection. fig. 2e heat transfer ratio w.r.t. cases. from the above figure case 5 represent the best case for the surface selection. fig. 2f represents the mass frontal area ratio w.r.t. cases. from the above figure case 7 represent the best case for the surface selection. fig. 2g represents the length ratio w.r.t. cases. from the above figure case 7 represent the best case for the surface selection. * pec for gasside, rectangular fins is the reference al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 11 from the above discussion cases 5 and 7 represents the best cases for the surface selection for the plate-fin heat exchangers. in the case of generating other new cases according to the procedure cited in this research, the cases 5 and 7 expected to remain best. conclusions 1-the performance evaluation criteria method, is constructed to be an archival source in years to come for selecting the reasonable case for optimization according to the designer’s own criteria. 2-the twelve cases in this research is in the method as shown. this method can be used to generate a large number of other cases, i.e. , the method in this research is a general for the optimal selection of heat transfer surfaces for any plate-fin heat exchanger. 3-cases 5 and 7 represents the best cases for the surface selection for the plate-fin heat exchangers. 4-a complete procedure for generating the cases for the optimal surface selection for the plate-fin surfaces. references 1. kays, w. m., and london, a.l., 1964, '' compact heat exchangers,” mcgraw-hill co., newyork. 2. kays, w. m., 1972, ''compact heat exchangers,'' in ''agard heat exchangers’’, agard -ls-57, advisory group for aerospace research and development, nato, paris. 3. kays, w. k., and perkins, h. c., 1973, '' forced convection, internal flow in ducts, '' in '' handbook of heat transfer '' edited by w. m. roshenow, and j. p. hartnett, chapter 7, mcgraw -hill co., new york 4. london, a.l., and ferguson, c. k. 1949, " test results of high performance heat exchanger surface used in aircraft intercoolers and their significance for gas turbine regenerator design, " trans. asme, vol. 71, pp. 17-26 5. shah, r. k., and london, a. l., 1978, '' laminar forced convection in ducts, '' supplement 1 to advances in heat transfer, academic press, new york. 6. shah, r. k., 1981a, '' compact heat exchangers design procedures, '' in '' heat exchangers: thermal hydraulic fundamentals and design, '' edited by s. kakac, a. e. bergles, and f. mayinger, hemisphere publishing corp., new york, pp. 495-536. 7. shah, r. k., 1981b, '' classification of heat exchangers, '' in '' heat exchangers: thermalhydraulic fundamentals and design, '' edited by s. kakac, a. e. bergles, and f. mayinger, hemisphere publishing corp., new york, pp. 9-46. 8. shah, r. k., 1981c, '' compact heat exchangers, '' in '' heat exchangers: thermal hydraulic fundamentals and design, '' edited by s. kakac, a. e. bergles, and f. mayinger, hemisphere publishing corp., new york, pp. 111-150. 9. shah, r. k., 1983, '' compact heat exchanger surface selection, optimization, and computeraided design, '' in '' low reynolds number flow heat exchangers, '' edited by s. kakac, r. k. shah, and a. e. bergles, hemisphere publishing corp., pp. 845-875. 10. shah, r. k., and webb, r. l., 1983, '' compact and enhanced heat exchangers, '' in '' heat exchangers: theory and practice, '' edited by j. taborek, g. f. hewitt, and n. afgan, hemisphere publishing corp., wahashington, d. c., pp. 425-468. 11. shah, r. k., 1978, '' compact heat exchanger surface selection methods, '' heat transfer, vol.4, pp. 185-191. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 12 12. kays, w. m., 1972, ''compact heat exchangers,'' in ''agard heat exchangers’’, agard -ls-57, advisory group for aerospace research and development, nato, paris. 13. webb, r. l., 1981, '' performance evaluation criteria for use of enhanced heat transfer surfaces in heat exchanger design, '' international journal of heat and mass transfer, vol.24, pp. 715-726. 14. webb, r. l., 1983a, '' enhancement for extended surface geometries used in air cooled heat exchangers, '' in '' low reynolds number flow heat exchangers, '' edited by s. kakac, a. e. bergles, and f. mayinger, hemispher publishing corp., new york, pp. 185-191. 15. webb, r. l., 1983b, '' performance evaluation criteria for selection of heat transfer geometries used in low reynolds number flow heat exchangers, '' in '' low reynolds number flow heat exchangers, '' edited by s. kakac, r. k. shah, and a. e bergles, hemisphere publishing corp., pp. 735-752. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 13 table(1): data of surface 10-27 (kays and london, 1964) mfinp f /437= 5.3=hd mmb 2.12= 32 /1023 mm=β mm2.0=δ re j f re j f 500 0.0103 0.038 2000 0.00375 0.0119 600 0.0089 0.0319 2500 0.00373 0.0112 800 0.00704 0.0243 3000 0.00368 0.0105 1000 0.00586 0.0198 4000 0.00353 0.00958 1200 0.00505 0.0166 5000 0.00338 0.00900 1500 0.0042 0.0137 table(2): data of surface 101 (kays and shah, 1964) mfinp f /984= 48.1=hd mmb 5= 32 /2358 mm=β mm2.0=δ re j f re j f 500 0.0207 0.0883 1200 0.0133 0.0528 600 0.0187 0.0772 1500 0.0121 0.0.0483 800 0.0162 0.0647 2000 0.0107 0.0437 1000 0.0145 0.0573 3000 0.0095 0.0398 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 14 (a) (b) fig. 1: (a) plain rectangular fin, and (b) plain triangular fin (shah, 1981 b). 0 0.5 1 1.5 2 2.5 1357911 case te m pe ra tu re d iff er en ce r at io 0 0.2 0.4 0.6 0.8 1 1.2 1357911 case m as s flo w r at e ra tio (a) (b) 0 0.5 1 1.5 1357911 case r e r at io 0 0.5 1 1.5 1357911 case p um pi ng p ow er r at io (c) (d) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 15 0 0.2 0.4 0.6 0.8 1 1.2 1357911 case h ea t t ra ns fe r ra tio 0 0.5 1 1.5 2 1357911 case fr on ta l a re a ra ti o (e) (f) 0 0.5 1 1.5 2 2.5 1357911 le ng th ra tio case (g) fig. 2: effects of the surface selection cases on the selected surface for plate-fin heat exchanger. article al-qadisiyah journalforengineering sciences 14 (2021) 042–047 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hasan.dawwood@qu.edu.iq (hasan i. dawood) https://doi.org/10.30772/qjes.v14i1.732 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. a comparative study on stability and thermal properties of various nanofluids marwa s.j. , hasan i. dawood٭ chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq. a r t i c l e i n f o article history: received 13 january 2021 received in revised form 11 april 2021 accepted 15 april 2021 keywords: heat transfer enhancement; nanofluids; thermal properties; hybrid nanofluids; base fluids. a b s t r a c t the attention of researches in convective heat transfer by suspended nanoparticles in base fluids has grown lately to promote uncommon techniques for enhancing the thermal performance of fluids. in this study, the stability period and thermal properties of aluminium oxide (al2o3), silicon dioxide (sio2) and al2o3–sio2 hybrid were investigated at volume concentration 0.1vol.% dispersed in distilled water (dw) as a base fluid. for the hybrid nanofluid, the samples were consisted of (0.025 vol.%al2o3+0.075vol.%sio2),(0.05vol.%al2o3+0.05vol.%sio2)and(0.075vol.%al2o3+0.025vol.%sio2). the two-step method was adopted to prepare the nanofluid samples by using ultrasonic device. three different ultrasonication times were fitted for preparing the samples (1hr,2 hr and 3 hr).the properties of single and hybrid nanofluids were evaluated at various temperatures (from 30 °c to 70 °c). the obtained results demonstrated that the dispersion of nanoparticles was homogeneous and more stable for a longer period for all samples that prepared at 3 hr of ultrasonication process. among all samples of nanofluids, sio2/dw was found to be the most stable coolant. for all nanofluids, with an increase of temperature, the thermal conductivity and specific heat were increased significantly while density and viscosity were decreased. ©2021 university of al-qadisiyah. all rights reserved. 1. introduction improving warmth move rates by using nanofluids has drawn huge considerations from analysts around the globe. ordinary strong nanoparticles, size of 1-100 nm with high warm conductivities, are suspended in the base liquids that have low warm conductivities. the nanofluids have demonstrated an upgrade in viable warm conductivities and the convective warmth move coefficients of the first base fluid[1]. nano-fluid, a collection of nanomaterials in a continuous and saturated liquid, has been known to be capable of achieving significantly higher thermal conductivity than the associated base liquid, causing an enhancement in heat transfer coefficients [2].hybrid2nanofluid as an expansion of nanofluid is obtained by scattering composite nano-powder or two diverse nanoparticles in the base liquid. it is accepted that half breed nanofluid will offer great warm qualities when contrasted with the base liquid and nanofluid containing single nanoparticles because of synergistic impacts[3]. a blend of nanofluids happens only utilizing remarkable techniques like as one stage and two-advance strategies. steady and quality nanofluids are integrated utilizing these strategies to use them for any warmth move and exploratory purposes. according to various authors, physical properties of nanofluids is influenced by several factors. temperature is the most important factor which plays a significant role in the nanofluid thermal performance. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ marwa s.j. , hasan. i. dawood /al-qadisiyah journalfor engineering sciences 14(2021) 042–047 43 [4] claimed that nano-fluids could be better than traditional working fluids like ethylene glycol (eg) and water due to the more beneficial and encouraging heat transfer properties of nano-fluids. [5]used al2o3 nanoparticles with 4.3 vol.% and noted that an increase in the warm conductivity of water under fixed conditions by 32.4%. [6] thought about the warm conductivity between cu-eg nanofluid and unadulterated eg. the outcome showed that 40% expansion in warm conductivity of cu-eg nanofluid at volume portion of 0.3 vol%. as indicated by [7], a superior improvement in warm conductivity can be produced by hybridizing silver nano-particles with multi-walled carbon nanotube (mwcnt). approximately half nanoparticles have demonstrated an astounding improvement regarding cooling adequacy contrasted with single nanoparticles and water. [8] arranged suspension of tio2 and al2o3 nanoparticles by a two-advance technique by scattering 0.05 vol.% and 0.3 vol.% in the blend of water and eg which was mixed for 30 min utilizing an attractive stirrer followed by ultrasonication utilizing an ultrasonication for 2 hr. they proposed that tio2 more steady than al2o3 in water/eg blend. [9] compared to nano-fluid that have single nanoparticles and water, hybrid nanoparticles have exhibited a significant improvement in cooling system performance [10]. stabilized single walled carbon nanotubes (swcnt) functionalized with the carboxyl group (cooh) –water /eg by. the functionalized swcnt with different solid volume fractions were added to the base fluid, using a two-step method. the finds obvioused that the nano-fluid samples was stable for two weeks and its had a long stability with no comprehensible precipitation. [11]inspected thermo-physical properties (warm conductivity, thickness, consistency and explicit warmth) of nanofluids containing al2o3 nanoparticles in water/eg blend (50:50). the ascent in temperature demonstrated improvement in warm conductivity and specific heat while the density and viscosity were decreased.[12] estimated warm conductivity of zno-ag (50 %:50 %)/water by considering different temperatures (25°c– 50°c) at 2 vol.%. the maximum thermal conductivity was achieved at 50°c. [13]analyzed the thermal behavior of a functionalized graphene nanoplateletplatinum (gnppt) hybrid nano-fluid at temperatures ranging from 20°c to 40 °c. they mentioned that the hybrid nano-fluid density was correlated with the temperature . gnp-pt/water hybrid nano-fluid density decreased with the rise in temperature from the observational investigation. from the findings of yarmand et al[14]on the activated carbon/grapheme (acg)/egg hybrid nano-fluid. it was established that when the temperature increases significantly, the specific heat of nano-fluids was greater than that of the base fluids. for thermal performance testing, nano-fluid viscosity is a parameter as important as thermal conductivity, density and specific heat. dardan et al[15]demonstrated the viscosity relationship with respect to the difference of al2o3-mwcnt/nano-fluid oil temperatures. and as per the results, with temperature, viscosity was dramatically decreased, with temperature increase. the main objective of this paper is to get a nanofluid with promising advantages by adding al2o3 and sio2nanoparticles to dw. adopting the two-step method to prepare nanofluid samples and highlighting on the effect of ultrasonication time on the stability of nano-suspensions. the thermophysical properties of nanofluids were evaluated at temperatures from 30 °c to 70 °c. 2. experimental steps : 2.1. nanofluids preparation: two kinds of oxide nanoparticles were utilized for this investigation: al2o3 nanoparticles produced by ( hongwu, universal group.ltd) and sio2 manufactured by us exploration nanomaterial's, inc. (novascientific assets (m) sdn. bhd). both nanofluids were readied with dwas base fluid. the properties of these nanoparticles are shown in table 1. table 1:physical, morphological and thermoproperties of al2o3 and sio2 nanoparticles. properties11 (al2o3) (sio2) color11 white white particle size 50 nm 50 nm purity 99.99% 99.8% morphology1of2particles spherical spherical form11 powder powder density (g.cm-3) 3.9 2.4 thermal conductivity (k) (w.m−1 .k−1) 40 [16] 1.4 [17] specific heat (cp) (j / kg.k) 773 [16] 745 [17] the particles shape and microstructure that studied with scanning electron microscope (sem) are explain in fig. 1a-b. the examination was conducted in the scientific research department / ministry of higher education and scientific research. the nanoparticle suspensions in dw were subjected to ultrasonic vibration for 1hr,2hr and 3hr at room temperature as in fig. 2. the weight of al2o3and sio2 nanoparticles that used to prepare the nanofluid samples are explained in table 2. table 2:the weights in gm of al2o3and sio2 nanoparticles in the samples. no. sample weight 1 0.1 vol.% al2o3 39.04 2 0.1 vol.% sio2 24.04 3 0.05 vol.% al2o3 + 0.05 vol.% sio2 31.49 4 0.075 vol.% al2o3 + 0.025 vol.% sio2 35.24 5 0.025 vol.% al2o3 + 0.075 vol.% sio2 27.79 the next step, adequate quantities of dw were added to the underlying suspensions and altogether blended to accomplish the expected nanofluids. the volume concentrations of single and hybrid nanofluids are evaluated from the following equations[18]: volume concentration (𝜑) = [ 𝑊𝑛𝑝 𝜌𝑛𝑝 𝑊𝑛𝑝 𝜌𝑛𝑝 + 𝑊𝑏𝑓 𝜌𝑏𝑓 ] × 100 (1) nomenclature dw distillate water 𝑛𝑝 nanoparticles k thermal conductivity (w m-1 k-1) 𝑤 the weight( kg ) 𝐶 specific heat (j kg-1 k-1) 𝜇 viscosity in mpa.s 𝑏𝑓 base2fluid3 𝜌 the density of the nanoparticles ( kg . m -3) 𝑛𝑓 nanofluid 𝜑 volume concentration 44 marwa s.j. , hasan. i. dawood /al-qadisiyah journalfor engineering sciences 14 (2021) 042–047 𝜑 = [ [ 𝑊𝑛𝑝 𝜌𝑛𝑝 ] 𝐴𝑙2𝑂3 + [ 𝑊𝑛𝑝 𝜌𝑛𝑝 ] 𝑆𝑖𝑂2 [ 𝑊𝑛𝑝 𝜌𝑛𝑝 ] 𝐴𝑙2𝑂3 + [ 𝑊𝑛𝑝 𝜌𝑛𝑝 ] 𝑆𝑖𝑂2 + 𝑊𝑏𝑓 𝜌𝑏𝑓 ] × 100 (2) 2.2.evaluation of the physical properties for nanofluids the thermal conductivity of nanofluids is a significant property when evaluating warm proficiency. estimations were performed with temperature assorted variety between 30 °c and 70 °c. to evaluate the warm conductivity of nanofluids, kd2 ace warm properties analyzer (decagon gadgets, usa) was used as in fig. 3a-b. the examination was conducted at the university of babylon / college of engineering / department of chemical engineering .the kd2 was adjusted by utilizing dw at the room temperature before estimations, and the exactness of these estimations was fated to be inside 1%. the measurements of physicothermal properties for nanofluids (density, specific heat and figure 1:a. general shape of al2o3 and sio2particles b. sem of nanoparticles figure 2: ultrasonic device viscosity) are necessary to apply for practical applications. appropriate correlations to assess the density of single nanofluids were provided by pakand chu [19]that have been identified as follows: 𝜌𝑛𝑓 = 𝜑𝜌𝑛𝑝 + (1 − 𝜑)𝜌𝑏𝑓 (3) specific heat of single nanofluids was calculated using xuan and roetzel’s [20] equation: (𝜌𝐶)𝑛𝑓 = 𝜑(𝜌𝐶)𝑛𝑝 + (1 − 𝜑)(𝜌𝐶)𝑏𝑓 (4) figure 3:a. thermoproperties analyzer b. schematic diagram of thermal conductivity measuring. to measure the densities and specific heat of hybrid suspensions of al2o3and sio2nanoparticles, the theoretical formulasthat predicted by ho et al.[21]were used as follows: 𝜌𝑛𝑓 = [𝜑𝜌𝑛𝑝 ]𝐴𝑙2𝑂3 + [𝜑𝜌𝑛𝑝 ]𝑆𝑖𝑂2 + (1 − 𝜑𝐴𝑙2𝑂3 − 𝜑𝑆𝑖𝑂2)𝜌𝑏𝑓 (5) (𝜌𝐶)𝑛𝑓 = [ 𝜑𝜌𝐶]𝐴𝑙2𝑂3 + [ 𝜑𝜌𝐶]𝑆𝑖𝑂2 + (1 − 𝜑𝐴𝑙2𝑂3 − 𝜑𝑆𝑖𝑂2)(𝜌𝐶)𝑏𝑓 (6) to predict the viscosity of nanofluids, the formula derived by brinkman [22]was used.all samples that used in this study which have different component fractions of al2o3 and sio2were considered to have the same viscosity because of particle’s spherical shape and the volume fraction of samples between 0.01 vol.% and 2 vol.% [23]. 𝜇𝑛𝑓 = 𝜇𝑏𝑓 (1−𝜑)2.5 (7) 3. results and discussion tests were performed with dw and various samples of nano-fluids which were prepared with different ultrasonication times (1hr,2 hr and 3 marwa s.j. , hasan. i. dawood /al-qadisiyah journalfor engineering sciences 14(2021) 042–047 45 hr). the study was carried out with the range of temperature (30,40,50,60 and 70°c) at 0.1vol.%. the observation obtained from the present investigation is discussed below: 3.1. dependability time of nanofluids the impact of ultrasonication times on resting period as appeared in table 3. due to the little size of nanoparticles, it has a high propensity to shape groups or agglomerates because of van der waals powers. ultrasonication technique helps to break these bonds between the nanoparticles and increase the random motion of the nanoparticles that suspended in the base fluid.the augmentation in ultrasonication time lead to an increment in the random motion of this nano-powder and will create a slip speed between the particles and the liquid medium[24]. the experimental results show a good agreement with the previous articles [25, 26]. besides, the challenge of how to effectively prevent nanoparticles from agglomeration or aggregation, the key issue is the weight of nanoparticles that are used to form more stable nanofluids.the best consequences were gotten for the sample 0.1 vol.% sio2, where it recorded the longest period of stability which was about 15 day with ultrasonication time 3 hr.the reason is due to the total weight of nanoparticles that used in 0.1 vol.% sio2 is less than weights that utilized in other samples to prepare them with the same volume concentration, which ensures the possibility of better distribution and a longer sedimentation time[25].fig. 4 explain the sedimentation time for the sample 0.1vol.%of sio2 after 15day. table 3: stability period (day) of nanofluid samples at room temperature samples ultrasonication time 1hr 2 hr 3 hr 0.1 vol.% al2o3 7 9 11 0.1 vol.% sio2 9 11 15 0.05 vol.% al2o3 + 0.05 vol.% sio2 8 10 13 0.075 vol.% al2o3 + 0.025 vol.% sio2 7 9 12 0.025 vol.% al2o3 + 0.075 vol.% sio2 8 10 13 figure 4: sedimentation time for the sample 0.1vol.%of sio2 after 15day 3.2.effect of temperature on physical properties 3.2.1.thermal conductivity fig. 5 introduces the variation of nanofluid thermal conductivity as a function of temperature for dw and all the studied nanofluid samples. by observing the results, the warm conductivity of the nanofluids increments with increment in temperature. with the ascent in temperature, while loosening the intermolecular bonds, the randombehaviour of nanoparticles liquid collision will increase [6]. this is known asbrownian motion which suggested by xuan and roetzel [20]. moreover, these results agree with the literature [27]. the spontaneous behavior of suspended nanoparticles in liquid media will increase as temperature goes up ,and weakening molecular bonds [28]. that is called a brownian motion as proposed by xuan and roetzel [29]. besides, the increase in vol.% of al2o3 at the component of nanofluids, the thermal conductivity will increase. due to the high thermal conductivity of al2o3 nanoparticles, as compared to sio2 nanoparticles, it leads to an important role for the better enhancement in the physical properties of base fluid [16]. figure 5: thermal conductivity of dw and various nanofluids as a function of temperature. 3.2.2.density the physical properties of nanofluid is specified by each of nanoparticles and base fluid. the density of nanofluid is one of these properties that changes according to the density of nanoparticles and the base fluid. since the solid have a density greater than the liquid, the adding of the nanoparticles will raise the density of the base fluid. fig. 6 presents the experimental data of densities that measured for dw andnano fluids (single and hybrid phase) with different temperatures.the figure shows that the al2o3/dw has a higher density than other nanofluids at all temperatures, because of the high density of al2o3 nanoparticles[16]. for the hybrid nanofluids, density increased with increase in the quantity of al2o3 nanoparticles due to its high density compared to sio2 nanoparticles[21]. it is shown also that density decreases with the increase of temperature to 70 °c for all samples and the decreasing tendency was slight. with the rise in temperature, the volume usually increases because the faster-moving molecules are further apart, which is cause a slightly decreasing in the density [21]. 46 marwa s.j. , hasan. i. dawood /al-qadisiyah journalfor engineering sciences 14 (2021) 042–047 figure 6: densities of dw and various nanofluids as a function of temperatures 3.2.3.specific heat heat transfer is significantly influenced by specific heat. specific heat of nanofluid as the other physical properties depends on suspended nanoparticles and the base fluid .fig. 7 shows the changes in specific heat for all nanofluids samples at various temperatures. moreover, as shown in this figure, the specific heat of dw ishigher than other samples. the lower specific heat of nanoparticles is the reason that explains why the specific heat value of the mixture becomes lower than that of base fluid ( 4179.6 j / kg.k) [11].according to the data of this study, with an increase in temperature, the specific heat israised steadily and linearly.as the substance warms up, the normal dynamic vitality of the atoms increments. the crashes give enough vitality to permit turn to happen, at that point adds to the inside vitality and raises the particular warmth[30]. it seems that specific heat of produced nanofluid depends on the type of dispersants where with increase the volume fraction of sio2 to al2o3in base fluid , the specific heat will decrease . that because of the specific heat capacity of sio2 nanoparticles less than al2o3 nanoparticles[31]. 3.2.4.viscosity viscosities of tried examples were estimated in the temperature scope of 30 °c–70 °c and plotted in fig. 8. [6, 32] indicated that there is an immediate connection among temperature and consistency of all trials in all conditions contrasted with the base liquid. it is observed that expanding temperature of the nanofluid diminishes its thickness. as the temperature expands the vitality level of fluid particles increments and the separation between the atoms increments and causes an abatement in intermolecular fascination between lessening inconsistency [16]. figure 7: specific heat of dw and various samples as a function of temperatures. figure 8: results of dw and 0.1vol.% sample viscosities relative to temperatures. 4. conclusions in the present experimental study, the stability period of aluminium oxide(al2o3), silicon dioxide(sio2) and al2o3–sio2 hybrid was investigated at various ultrasonication times. also, thethermal propertiesof dw and samples have been estimated at five different temperatures. the conclusions of the study are elaborated below: the stability period increases with increasing the ultrasonication time for all samples. the sio2 nanofluid was found to be the most stable coolant, while al2o3 was found the lowest stable nanofluid.for the hybrid samples, the stability period increases with the increasing volumetric concentration of sio2nanoparticles in the nanofluid. the thermal properties of nanofluids dependent directly on the temperature. moreover, with increasing temperature, the thermal conductivity and specific heat of nanofluid increase,while density and viscosity decrease. the outcome of physical properties (thermal conductivity, density and specific heat) show that 0.1 vol.% al2o3/dw has good results when compared to other working fluids.this means that the al2o3 nanoparticles had a preferable thermal performance than sio2 suspensions. for the hybrid nanofluids, the thermal properties showed good results with expanding the volume part of al2o3 nanoparticles in the base fluid. references [1] m.u. sajid, h.m. ali, recent advances in application of nanofluids in heat transfer devices: a critical review, renewable and sustainable energy reviews, 103 (2019) 556-592. 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[32] m. gupta, v. singh, r. kumar, z. said, a review on thermophysical properties of nanofluids and heat transfer applications, renewable and sustainable energy reviews, 74 (2017) 638-670. article al-qadisiyah journal for engineering sciences 15 (2022) 192–201 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: jboscosamon@gmail.com (jean samon) https://doi.org/10.30772/qjes.v15i3.835 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. analysis of coupling methods: a review jean bosco samon*, jemimah maurelle ndomou, and damasse harold fotsa laboratory of mechanics, materials and photonics, department of mechanical engineering, ensai-university of ngaoundere, bp 455, cameroon a r t i c l e i n f o article history: received 15 jone 2022 received in revised form 20 august 2022 accepted 25 september 2022 keywords: multiphysics multiphysics system mechatronics mechatronics system coupling methods a b s t r a c t the multiphysics field is a branch of physics whose objective is to the couple at least two physical systems. each is governed by its own principles of evolution or equilibrium such as balance laws or constitutive laws. many engineering problems can only be described correctly by coupling fields of physics that have historically been developed and taught separately. these problems require on the one hand a good understanding of each physical domain, but above all an analysis of the coupling mechanisms of these physical domains, in order to propose a relevant model capable of solving the problem. a challenge in the multiphysics (mechatronics) field is the construction of coupled multiphysics models from experimental observations, as well as the analysis of their mathematical properties. the mathematical analysis of the coupled model must be able to show the well-posedness of the problem at the defined boundary and initial values. for this reason, we have identified several coupling methods: newton, gauss-seidel, jnfk, and direct and explicit coupling. from these methods, it appears that the newton method is suitable for the coupling of the different disciplines of mechatronics. a summary table shows the comparative advantages of each method. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the compartmentalization of trades and physical disciplines, combined with the weakness of computer resources with the emergence of numerical calculation has led to the creation of specialized simulation tools. however, the phenomena studied often mix several disciplines. the need for multiphysics simulations thus appeared very early on [20]. the field of multiphysics is a branch of physics whose objective is to couple two or more physical systems, each governed by its own principles of evolution or equilibrium, such as balance laws or constitutive laws [1]. many engineering problems can only be described correctly by coupling fields of physics that have historically been developed and taught separately [21]. this is called coupling. there are two traditional responses to this need. the first is to incorporate simplified models (which can be fed by reference calculations) from other physics disciplines into a specialized code. the second is the sequential execution of several codes exchanging information. both approaches have in common the implementation of penalty levers to guarantee the conservatism of the physical response obtained by the modelling. the increase in computing capacity and the desire to improve the modelling associated with the complexity of the technologies studied are increasing the interest in multiphysics simulations. these objectives are recurrent, but it is not at all certain that they will be achieved if attention is not paid to the way the coupling is carried out. having separate simulations communicate may introduce limitations in stability, accuracy and robustness that are stronger than those of the components. in addition, the exchange of information may itself be more costly than the execution of the coupled codes. these challenges have led the scientific community to develop efficient and robust coupling techniques. this article is part of this http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i3.835 http://creativecommons.org/licenses/by/4.0/ jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 193 process. after defining the coupling system, we will present two families of associated coupling methods. we have deduced a method suitable for mechatronic systems. 2. some definitions of the concepts according to [2] coupling is an approach that can be used as a unifying basis for modeling the different domains of mechatronics. we can therefore say that coupling is the unambiguous connection between two or more inputs of the same system. it is then for us to define a coupled system. according to [23] a system is a set of entities that interact and evolve over time. the entities can be continuous or discrete fields. their evolution is governed by odes1 or pdes2. he thus defines a coupled system as a system made up of several interacting subsystems. they can be differentiated by the model (conservation law, behavioral, etc.) or the numerical methods used. these subsystems interact through interfaces. geometrically, an interface can correspond to a boundary or to a part or the whole spatial domain. as a sketch, we have fig. 1 below. figure 1 arrangement of the subsystems [2] figure 2 family of couplings [3] this figure shows us that the subsystems can be adjacent (fluid-structure, solid body dynamics), or overlap each other (overlapped). partial overlaps are also possible (e.g. electromagnetic-mechanical). in their paper entitled "stabilization of staggered solution procedures for fluid-structure interaction analysis", [3] discussed the difficulty of stability in the coupling method. it is this difficulty that has challenged the researchers to the point of leading them to a solution to the problem, namely the different coupling algorithms. the latter are grouped into two families qualified respectively as weak coupling and strong coupling which we shall begin by presenting. let us note that the type of coupling between two subsystems (each physical for example) can be qualified as "strong" or "weak" as shown in figure 2. concerning the "strong coupling": there is a significant influence of the two subsystems on each other. for "weak coupling": only one subsystem has a significant influence on the other subsystem. the fundamental difference between these two families comes from the way of imposing equilibrium between the different physical systems, i.e. the action-reaction principle. it can also be compared in terms of their speed of convergence. this is measured by the coupling force. the coupling "strength" is determined by the equations of the mathematical model. the value of the coupling "strength" between the subsystems is given by a scaled writing of the model equations which allows some scaled numbers to appear. 2.1 weak coupling family this is the first type of coupling to be used in design offices. it is very present in industrial software. this type has the advantage of concentrating the calculation effort on the zones that require it. however, it is mainly reserved for cases where the local detail has little or no influence on the rest of the structure on a global scale. for this reason, a mathematical modeling of weak coupling will be presented in the following. consider a dynamic system whose state is described by the vector u(t)={u_1 (t),u_2 (t)}and governed by the following differential system: { u̇ = ℱ(u, t); u(t = 0) = u0. (1) the coupling between the two subsystems described by their respective entities u1(t) et u2(t) or components ℱ1 𝑒𝑡 ℱ2 are both functions of u1(t) et u2(t)the coupling between the two subsystems, described by their respective entities or components, is said to be weak if only subsystem 1 has a significant influence on the second one. ℱ1(u1, u2, t) ≈ ℱ1(u1, t). (2) that is: { u̇1 u̇2 } = { ℱ1 (u1, t) ℱ2(u1, u2, t) } (3) in the weak coupling model, each of the partial differential equations is solved separately. in the weak coupling model, each of the partial differential equations is solved separately, which requires the transfer of the results of one partial differential equation to the other. in such a case, each system may involve a different mathematical type of variable (real or complex), different time constants or pulses, and different study areas. 2.2 strong coupling family in the case where the influence of the local model extends beyond its definition domain, it is easy to understand that weak coupling methods will produce a more or less erroneous solution depending on the situation [4-5]. therefore, the only way to build an exact coupled solution is to bring the information from the solution of the local problem to the global level. this is the principle of strong coupling methods. in this type of strong coupling, we have direct and iterative coupling methods. 2.2.1 direct coupling methods 194 jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 these methods take their name from the fact that the coupling between two models is considered by means of a direct calculation, i.e., without using iterative processes. they can be classified into two main categories: structural reanalysis methods and static condensation structural reanalysis methods. the principle of structural reanalysis is to calculate the response of a structure after a (often localized) change from the principle of structural reanalysis is to calculate the response of a structure after a (often localized) modification from the knowledge of the response before modification. most of the time, the procedure consists in evaluating the response of the initial system under different elementary stresses (e.g., m) representative of the modification made to the structure. this is then done by correcting the initial stiffness operator by a matrix of rank m. this correction can then be carried out in a non-intrusive manner with respect to the operator through the sherman-morrison and woodbury formulae woodbury formulae [8]. let {ui}i=1...m be a family of vectors constructed from the responses under elementary stresses. if u = [u1, ..., um] then the response of the modified structure can be calculated in a non-intrusive way (i.e., without requiring the assembly and factorization of the modified system): (k + uut )-1 = k-1 k-1 u (ut k-1 u + i) -1 ut k-1 (4) structural reanalysis methods are therefore based on an a posteriori modification of the solution, in contrast to static condensation methods. we take the example (fig.3) of a structure occupying the domain ω that is partitioned into a global part ωg and a local part ωl figure 1 partition of the study area (park and felippa, 2000). it is assumed that a localized defect in ωl is taken into account. even if the solution in ωg can be affected by the alteration of the model in the local area, the finite element representation of the model defined in ωg always remains the same. if the model defined at ωl were to evolve or be modified many times (for example during a parametric study), a complete recalculation of the whole structure would require a significant and unnecessary additional cost. static condensation sub structuring provides a solution to this problem by allowing the construction of a model representing the behavior of the structure in ωg involving only the degrees of freedom of the interface γ [6-7]. we consider here the case of a displacement connection under the assumption that the mechanical problem is formulated in primal variable. the global model kg ug + c ul = fg can be condensed so that only the interface displacement has to be considered. the superscripts i indicate the internal degrees of freedom of the models, and the superscripts b indicate the degrees of freedom of the interface. the schur complement of kg, noted can thus be used to substitute the global model in equation (5). this gives the following equation 6: in this case, static condensation is used as a decoupling method to connect a fixed global model to a detailed and possibly modifiable local model. sometimes, this method is also used to provide an indelible finite element model in the form of a "black box" to protect an industrial secret for example. indeed, the only knowledge of the schur complement allows an exact consideration of the model, without having access to the details of the latter (geometry, loading cases). in the context of a generic and succinct presentation of the most used coupling methods to date, we refer here to static condensation. however, it should be noted that the process of sub structuring finite element models is more general and can also be used in dynamics and modal calculation. also, nothing prohibits the joint use of static condensation with other coupling methods, as is the case in hirai who combines static condensation with structural reanalysis [9]. 2.2.2 iterative coupling methods as we have just seen, direct coupling methods imply a certain level of interoperability of the solvers used by each of the coupled models. interoperability of the solvers used by each of the coupled models. the other major family of coupling methods commonly used are the iterative methods. successive resolutions are performed on the different parts of the model that are to be coupled. among the common iterative coupling methods are those based on sub structuring [22]. as presented earlier, the structure can be partitioned into substructures. the idea is then to solve the interface problem, but this time in an iterative way (for example via a conjugate gradient method). the other major class of iterative coupling methods concerns the so-called schwarz methods [8]. the alternating schwarz method, historically the oldest, proposes to split the study domain into several domains. the problem is then solved alternately in each of the sub-domains. if we assume a division of the domain into two parts ω1 and ω2, then the solution of the problem according to the alternating schwarz method will be done as follows (equation 7): jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 195 alternating schwarz: this method thus assumes that the problem is solved on each sub-domain successively. with the advent of computers with distributed architecture, the parallel schwarz method (equation 8) appeared. in this case, at each iteration, the problems per subdomain are solved in parallel, in order to take advantage of the potential of such computational means. schwarz parallel in the case where we consider a division of the structure into two subdomains, these two methods are equivalent since the sequences of solutions thus formed are the same in ω1 or ω2. we also speak of a multiplicative schwarz method for the alternate method and an additive schwarz method for the parallel method. the rewriting of these methods in the form of a fixed point reveals a sum of operators defined on ω1 and ω2 respectively for the parallel method and a product for the alternate method. finally, we will mention here the "finite element patch" type methods [1718], generally used for solving multiscale problems. the idea is to consider the solution u as the sum of a global contribution ug and a local contribution ul provided by the patch so that u = ug + ul. as with the schwarz methods, different strategies are then possible for the imposition of boundary conditions at each iteration. the main interest of such a method is to be able to calculate a local correction in a flexible way, i.e., to make the definition of the local patch independent of the characteristics of the global model. contrary to direct methods, iterative methods require only weak interoperability between the different models (and thus solvers) used. this makes them very good candidates for the development of nonintrusive methods. 2.2.3 connections between different models whatever the coupling method used, it is necessary to establish a connection between the different models involved. two types of connection can be distinguished: interface connections, which aim to establish relationships between the quantities of interest at the interface. in this category, we will find weak connection methods such as the "mortar" method [10-12]. the principle is to impose the equality of quantities (displacement, effort) in the weak sense, i.e., through a duality relation. such a connection can be used within strong coupling methods to lead to hybrid finite element methods. another example is the nitsch method [13-15] which allows a dirichlet edge condition to be imposed in a weak form, by adding an extra work term in the vibrational formulation of the problem. volume connections through an energy average. in this case, the connection area between the different models is no longer an interface but a covering area: this is the harlequin method [16]. while a volume connection may offer more flexibility in defining the connection area, it is also much more intrusive than an interface connection method. this is because a volume energy connection involves the simultaneous consideration of the quantities defined in each of the models. an interface connection, on the other hand, only requires independent unidirectional exchanges between the different models. despite all these efforts, it sometimes appears that multi-scale/multi-model calculation methods cannot be used in practice. indeed, in an industrial context, most numerical simulations are performed using commercial software that has been developed and certified for predefined applications. thus, it is not always convenient to use such software to implement a given multi-scale/multimodel calculation. moreover, the recent development of supercomputers now makes it possible to carry out very ambitious simulations. current practices therefore increasingly consist in coupling different models rather than integrating all the required specificities into a single model. to overcome these difficulties, many authors have developed methods. this is what will be presented in the rest of this article. 3. stationary coupling methods suppose we have two codes 𝑓1 and 𝑓2 working on the variables 𝑥2 € r d2 and 𝑥1 r d1 . 𝑓1 gives us x1 knowing x2 , which we will note 𝑥1 = 𝑓1 (𝑥2) and vice versa, 𝑓2 gives us 𝑥2 as a function of 𝑥1 , i.e. 𝑥2 = 𝑓2 (𝑥1) . carrying out the coupling, therefore, consists of looking for the global solution which verifies equation 9. often the coupling will be formulated with a dependence of the functions 𝑓𝑖 in 𝑥𝑖 : there may be two reasons for this. this may be a choice not to try to converge each of the codes precisely until the common solution is reached. this is close to an intricate solution method. it also happens that it makes no sense to converge a code on xi without simultaneously updatingxj. by default, we will assume that the coupling is of the form (10). we will also sometimes rewrite the system in the following form: it is possible to a couple more than two equations with the techniques we present here. as the generalization is simple, to simplify the writings, we will limit ourselves to couplings between two disciplines. 3.1 gauss-seidel method a. presentation of the method the gauss-seidel method (often referred to as the picard method or 196 jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 iterations in the literature), which implements a flexible coupling, is very common and easy to implement. it is applied to ax=b (linear) systems with the matrix a having to be diagonal dominant. in this method, it is simply a matter of iterating on the resolution of the codes until convergence. and one does not stop the iterations from precision. nevertheless, given that the main concern is to see if the sequence of iterations converges and if so to what order. we will start by presenting the sequence of iterations, then we will find an equivalence with the fixed point equation and then we will check the convergence. let us note with an exponent n the iteration index. from initial data (x1 (0) , x2 (0) ), we iterate by posing: { x1 (n+1) = f1(x1 (n) , x2 (n) ) x2 (n+1) = f2(x1 (n) , x2 (n) ). (12) ε1 (n+1) = ‖x1 (n+1) − x1 (n) ‖ et ε2 (n+2) = ‖x2 (n+1) − x2 (n) ‖ we generally stop when the increments become small enough. we use this criterion for want of a better one, and we see that it does not give any information on the distance to the solution. it is easy to see that the method if it converges, can only converge to a solution to the problem. however, convergence is not systematic. b. equivalence with the fixed point the so-called "fixed point" algorithm is used to solve an equation of the type x = f(x). it consists in iterating as follows: x(n+1) = f(x(n)). (13) the gauss-seidel method can be seen as a fixed point by posing: x(n) = ( x1 (n) x2 (n) ) et f(x(n)) = ( f1(x1, x2) f2(x1, x2) ). (14) if one of our functions, say f1does not depend on the variable it is used to calculate, i.e. x1 (as is often the case), we notice that each iteration is equivalent to x2 (n+1) = f2( f1(x2 (n) ) , x2 (n) ) . this is another way of getting back to the fixed point, which has the advantage of reducing the dimension of the space in which we work. the following discussion of the gaussseidel method uses this equivalence. we will therefore be interested in the properties of the fixed point. c. general condition for convergence convergence condition: let ebe a complete metric space and f an application from e into e. if f is k contract i (i. e. ∀(a, b) ∈ e2 , d(f(a), f(b)) kd(a, b) with k < 1, d is the distance between two points of e.), then there exists a unique fixed point xsol of f and any sequence satisfying x(n+1) = f(x(n)) converges to xsol. d. practical conditions for convergence the last remark leads us to look at the neighborhood of the solution to determine whether the algorithm can converge. we use the taylorlagrange inequality for a function f in rm in rm of sufficient regularity. we note ja the jacobian of at a. if there is a real m such that ‖ja+h‖ ≤ m ∀t ∈ ]0,1[ then: ‖f(a + h) − f(a)‖ ≤ m ‖h‖ . (15) we note xsol the fixed-point solution (we assume the existence and uniqueness of the solution here). it is assumed that there exists a real m such that ‖jx‖ ≤ m ∀x ∈ b (xsol , r). b (xsol , r) is the ball of center xsol and radius r, any real. then we have more generally: ∀a, b ∈ b(xsol, r ), ‖f(b) − f(a)‖ ≤ m ‖b − a‖ (16) thus, if m < 1, this shows that f is contracting on b(xsol, r )and that the algorithm converges if x(0) ∈ b(xsol, r ) from the above. it is therefore sufficient that ‖jx‖ ≤ m < 1 around the solution. if we use the norm l 2we can write the following sufficient condition (ρ(a) denotes the spectral radius of the matrix a, i.e. ρ(a) = maxi|λi| where the λi are the eigenvalues, possibly complex, of a). ‖jx‖2 = √(ρ(jx t jx) ≤ m < 1 (17) this equation is valid in the vicinity of the solution, and the initialization is chosen in this vicinity. as before, the norm of the jacobian allows us to reduce the speed of convergence of the algorithm. we can look for a less demanding condition by using its properties: ∀a, for any matrix norm we have: ρ(a) ≤ ‖a‖ . ∀a, ∀ε there exists a matrix norm such that ρ(a) ≤ ‖a‖ ≤ ρ(a) + ε. thus if we have, in the solution xsol, ρ(jxsol ) < 1, for a certain norm we have ‖jxsol ‖ ≤ m < 1. by continuity of the norm, we then have with the same norm ‖jx‖ ≤ m′ < 1 on a neighborhood of xsol . we thus have a sufficient condition of local convergence (thanks to the equivalence of norms in finite dimension. it suffices to show the convergence of the sequence for any norm), less demanding than the previous one since the first proposition of the lemma tells us that ρ(a) ≤ √ρ(at a) ∀a. we will try to show that ρ(jxsol ) < 1 is in fact a necessary condition for "good we will try to show that ρ( ) < 1 is in fact a necessary condition of "good behavior of the algorithm" in a sense that we will specify. we will then say, by abuse of language, that it is a necessary condition of we will then say, by abuse of language, that it is a necessary condition of convergence. e. variant with relaxation a variant of the fixed-point method is to introduce a relaxation α > 0. this is called over-relaxation when α > 1. the iterations are then written. 𝑥(𝑛+1) = (1 α) 𝑥 (𝑛) + αf (𝑥 (𝑛)) (18) let us see what this gives us about the criterion and the speed of convergence. we see that by posing g = (1 α) id + αf with id identity matrix, we return to the classical fixed point with 𝑥(𝑛+1) = g(𝑥(𝑛)). the previous results therefore apply to g. let us first consider the onedimensional case. jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 197 one-dimensionnel case : we have 𝑔′ = (1-α)+α𝑓 ′. the fixed point converges at its maximum speed when the derivative of the function is zero in the solution. this leads us to an optimal relaxation: α = 1 1− 𝑓′(𝑥𝑠𝑜𝑙) . this value will generally be unknown since it is based on a property of (f) in the solution 𝑥𝑠𝑜𝑙 which is unknown a priori. we will therefore look more generally at the behaviour of the algorithm as a function of α. the convergence criterion |𝑔′(𝑥𝑠𝑜𝑙 ) |< 1 gives us 𝑓 ′(𝑥𝑠𝑜𝑙 ) ∈ ]1 2 𝛼 ; 1[. the speed of convergence depends on the maximum value of |𝑔′ | around the solution x. compare 𝑔′ to 𝑓 ′. 𝑔′ 𝑓 ′ = (1 α)(1 𝑓 ′). since 𝑓 ′ < 1, we have 𝑔′ > 𝑓 ′ α < 1. now compare 𝑔′ à -𝑓 ′. 𝑔′+ 𝑓 ′ = (1 α) + (α + 1) 𝑓 ′. thus, 𝑔′(x) > -𝑓 ′(x) , α < 1+ 𝑓′(x) 1− 𝑓′(x) . thus, we have: • if 𝑓 ′(𝑥𝑠𝑜𝑙 ) < -1, i.e. if the algorithm, without relaxation, does not converge with an oscillating behavior, a relaxation α ∈ ]0, 2 1− 𝑓′(𝑥𝑠𝑜𝑙) [ allows it to converge. the optimum is α = 1 1− 𝑓′(𝑥𝑠𝑜𝑙) . • if 𝑓 ′(𝑥𝑠𝑜𝑙 ) ∈ ] 1, 0[, one can improve the speed of convergence with α ∈ ] 1 + 𝑓′(𝑥𝑠𝑜𝑙) 1− 𝑓′(𝑥𝑠𝑜𝑙) ,1[. the optimum is at α = 1 1− 𝑓′(𝑥𝑠𝑜𝑙) . • if 𝑓 ′(𝑥𝑠𝑜𝑙 ) ∈ 0, 1[, one can improve the speed of convergence with α ∈ ]1, 1 + 𝑓′(𝑥𝑠𝑜𝑙) 1− 𝑓′(𝑥𝑠𝑜𝑙) [. this is called over-relaxation. the optimum is at α = 1 1− 𝑓′(𝑥𝑠𝑜𝑙) . • if 𝑓 ′(𝑥𝑠𝑜𝑙 ) > 1, i.e. if the algorithm, without relaxation, has a nonconvergent behavior without oscillation, it will keep this behavior ∀α > 0. 𝑓 ′(𝑥𝑠𝑜𝑙 ) since the value of α is not known a priori, the difficulty is to determine α. more than one-dimensional case: to improve the convergence of g we will try to minimize the spectral radius of its jacobian at x, the solution to the problem. we have the following general property, which is easy to check, where σ(a) denotes the spectrum of a, i.e. the set of its eigenvalues: ∀a, ∀p polynomial p (σ(a)) = σ(p (a)). thus, the previous analysis, done in one dimension, applies to each of the eigenvalues of the jacobian of g. let us denote 𝜆𝑖 its eigenvalues, and 𝜆𝑖 (α) those obtained with relaxation. we have: 𝜆𝑖 (α) = 1 + α(𝜆𝑖 1). we seek to minimize 𝑚𝑎𝑥𝑖 |𝜆𝑖 (𝛼)|. as before, 𝜆𝑖 > 1 ⇔ 𝜆𝑖 (α) > 1 ∀α > 0. therefore, relaxation does not allow the algorithm to converge if ∃𝜆𝑖 > 1, and we, therefore, consider that 𝜆𝑖 < 1 ∀i. thus, we have 𝜆 𝑖 ′ (α) = (𝜆𝑖 1) < 0. all functions 𝜆𝑖 (α) have the same monotonicity and are all 1 in 0. moreover, it is easy to verify that if 𝜆𝑖 ≠ 𝜆𝑗 then 𝜆𝑖 (α)≠ 𝜆𝑗 (α) ∀α ≠ 0. let 𝜆𝐼 be the eigenvalue which realizes 𝑚𝑎𝑥𝑖 | 𝜆𝑖 |. it is easy to see that as long as 𝜆𝐼 (α) realizes 𝑚𝑎𝑥𝑖 |𝜆𝑖 (𝛼)|we can still decrease the spectral radius. and since, |𝜆𝑖 (𝛼)| = |𝜆𝑗 (𝛼)| ⟹ 𝜆𝑖 (α) = 𝜆𝑗 (α), we see that when ∃ i ≠ 𝐼 𝑡𝑒𝑙 𝑞𝑢𝑒 𝜆𝑖 ≠ 𝜆𝐼 𝑒𝑡 | 𝜆𝐼 (𝛼)| = |𝜆𝑖 (𝛼)| . since the monotonies are identical, we can no longer minimize both |𝜆𝐼 (𝛼)| and |𝜆𝑖 (𝛼)| . the optimum is thus reached. we notice that, since we have 𝜆𝑖 (α) < 1 ∀α > 0, the convergence of the algorithm is guaranteed at the optimum. 𝜆𝑖 (α)= -𝜆𝑗 (α) gives us: α = 1 1− 𝜆𝑖 +𝜆𝑗 2 . moreover, since the 𝜆𝑖 (α) cannot intersect, and 𝜆𝐼 corresponds to either the minimum or the maximum of the eigenvalues, the first 𝜆𝑖 ≠ 𝜆𝐼 which realizes | 𝜆𝐼 (𝛼)| = |𝜆𝑖 (𝛼)|is either the maximum (if 𝜆𝐼 is the minimum) or the minimum of the eigenvalues. the optimal relaxation, which we have seen ensures convergence, is therefore: α = 1 1− 𝑚𝑎𝑥𝑖𝜆𝑖 + 𝑚𝑖𝑛𝑖𝜆𝑖 2 . as in the one-dimensional case, the optimal relaxation we have identified requires knowledge of properties of (f) in the solution of the problem. it will therefore generally be necessary to use approximate methods. a very simple empirical procedure, which works whatever the dimension of the problem, often gives good results. it consists in dividing the relaxation by two each time the convergence criterion increases (be careful with its definition). it is possible, but not essential, to recalculate the iterations where the convergence criterion has increased. f. jacobi iterations the jacobi method is similar to the gauss-seidel method. the difference is that the result of the previous calculation is not used to improve the result of the next calculation. this is equivalent to iterating as follows (n is the iteration number): { x1 (n+1) = f1(x1 (n) , x2 (n) ) x2 (n+1) = f2(x1 (n) , x2 (n) ). (19) we can see that it is also a fixed-point method. the convergence is slower than for gauss-seidel, but the algorithm is parallelizable. the gauss-seidel method is generally preferred to the jacobi method. thus we can say that the gauss-seidel method is easy to implement and often converges. in particular, the convergence takes place whatever the initialization on the coupling is sufficiently weak. however, the method cannot converge if the couplings involved are too strong. adding a relaxation can be a solution in this case, but the difficulty is then to parameterize it. moreover, the linear convergence is all the faster that the functions studied are weakly coupled. 3.2 newton’s method a. presentation of the method this is another common method, which has many variants. in its original formalism, it is an intricate (and therefore firm) coupling method. let us put the system to be solved as follows (f1 and f2 can be taken from the formulation (20) for example): f (x) = ( f1(x1, x2) f2(x1, x2) ) = 0, x = (x1, x2) . (20) it is recalled that, in general, xi and fi(xi, xj) are vectors of r di . note that d= d1 + d2 the number of components of x and define the jacobian jx of the system at x as follows (the fi are here and for the following the components of f, and thus 198 jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 jx=( ∂f1 ∂x1 (x) ⋯ ∂f1 ∂xd (x) ⋮ ⋱ ⋮ ∂fd ∂x1 (x) ⋯ ∂fd ∂xd (x) ) (21) like the gauss-seidel method, the newton method is iterative. let us note here again with an exponent n the iteration index. from an initial data x(0) we iterate as follows: we solve in δx the linear system: jx(n) δx = −f(x (n). and then we pose x(n+1) = x(n) + δx . we generally stop when ‖δx ‖ or ‖f(x(n))‖ becomes small enough. as before, we see that the method can only converge to a solution of the problem. b. study of the method the method is based on a taylor expansion to order 1 around the solution xsol : f(xsol) = 0 ≈ f(x (n)) + jx(n) (xsol − x (n)). (22) assuming f is sufficiently regular, let us use the taylor-lagrange inequality to quantify the error. as before, let us note d2fx the linear application of rd in l(rd), such that (d 2fxab)k =∑ ∂2fk(x) ∂xi ∂xj aibji,j . if there is a real m such that: ‖d2fx(n)+t(xsol−x(n))‖ ≤ m ∀t ∈ ]0; 1[ then: ‖−𝐹(𝑥(𝑛)) + 𝐽𝑥(𝑛) (𝑥𝑠𝑜𝑙 − 𝑥 (𝑛))‖ ≤ m‖xsol−x (n)‖ 2 2 (23) since f(𝑥𝑠𝑜𝑙) = 0. we introduce the vector 𝜂𝑛of norm less than 1, such that: 𝐹(𝑥(𝑛)) = 𝐽𝑥(𝑛) (𝑥𝑠𝑜𝑙 − 𝑥 (𝑛)) + 𝜂𝑛 m‖xsol−x (n)‖ 2 2 . (24) we can therefore write the norm of the error as follows, assuming the jacobian is invertible: ‖ℰ (𝑛+1)‖ = ‖𝑥 (𝑛+1) − 𝑥𝑠𝑜𝑙 ‖ = ‖𝑥 (𝑛) − 𝐽 𝑥(𝑛) −1 𝐹(𝑥(𝑛)) − 𝑥𝑠𝑜𝑙 ‖ (25) ‖ℰ (𝑛+1)‖ = ‖𝑥(𝑛) − 𝐽 𝑥(𝑛) −1 ( 𝐽𝑥(𝑛) (𝑥𝑠𝑜𝑙 − 𝑥 (𝑛)) + 𝜂𝑛 m‖xsol−x (n)‖ 2 2 ) − 𝑥𝑠𝑜𝑙 ‖ (26) ‖ℰ (𝑛+1)‖ = ‖𝐽 𝑥(𝑛) −1 𝜂𝑛‖ m‖ℰ (𝑛)‖ 2 2 ≤ ‖𝐽 𝑥(𝑛) −1 ‖ m‖ℰ (𝑛)‖ 2 2 . (27) let k = max𝑚𝑎𝑥𝑥∈𝐵(𝑥𝑠𝑜𝑙,‖𝑥𝑠𝑜𝑙−𝑥(0)‖( 1 2 ‖𝐽𝑥 −1‖‖d2fx‖). 𝐵(𝑥𝑠𝑜𝑙 , ‖𝑥𝑠𝑜𝑙 − 𝑥 (0)‖ is the ball of center 𝑥𝑠𝑜𝑙 and radius ‖𝑥𝑠𝑜𝑙 − 𝑥 (0)‖ convergence occurs if the following criterion is met: 𝐾‖𝑥(0) − 𝑥𝑠𝑜𝑙 ‖< 1. (28) furthermore, it can be shown by recurrence that we have: ‖ℰ (𝑛)‖ ≤ (𝐾‖𝑥(0)−𝑥𝑠𝑜𝑙‖) 2𝑛 𝐾 . (29) this shows us that we have a quadratic convergence, thus faster than the gauss-seidel one, if the initialization is good enough. newton’s algorithm can only be defined correctly if we can define the jacobian of f at all points. however, it happens that the phenomena we are studying introduce breaks in the slope. we are thinking of phase changes. in this case, the previous equations assure us that the convergence of the algorithm always takes place, for a sufficiently good initialization, whether we choose the partial derivatives on the right or on the left at the breaks in the slope. c. variant with relaxation in the same way that we introduced a relaxation for gauss-seidel, it is possible to define one for newton, which we will note α ∈]0; 1] and which occurs as follows (δx is always calculated in the same way): x(n+1)=x(n)+αδx . (30) it is easy to see that when α ≠ 1 one loses the quadratic convergence speed of newton's algorithm. relaxation cannot therefore be used to accelerate convergence, but it can allow convergence in certain situations where the initial algorithm would not have done so. the jacobian is then mainly used to determine the direction in which the x(n) and α determines the size of the "step" taken. in principle, we can see that we are approaching a gradient descent type of algorithm, used. let us insist on the fact that α = 1 will always be optimal when approaching the solution for the newton algorithm, which was not the case for gauss-seidel. when using a relaxation with newton's algorithm, one must therefore have the possibility, at each iteration, to increase α. as with gauss-seidel, there is a simple empirical procedure for using relaxation with the newton method. this involves adding an internal iteration level. each newton iteration starts with α = 1. this iteration is then recalculated by dividing the relaxation by two each time, as long as the resulting residual is not smaller than that of the previous iteration. d. newton's algorithm does not correct it is simply a newtonian algorithm in which it is assumed that the solution of the system jx(n) δx = −f(x (n)) is not exact. starting with an initial data x(0) we iterate as follows: we determine δx which verifies: ‖jx(n) δx + f(x(n))‖ ≤ 𝜂(n)‖f(x(n))‖. and we pose x(n+1) = x(n)+ α(n)δx. 𝜂 (n) ∈ [0; 1] fixes the required precision on the resolution of the linear system and α(n)> 0 corresponds to a relaxation as already introduced. as the resolution of the linear system is assumed to be inaccurate, the algorithm does not benefit from the quadratic convergence speed of the newton and the introduction of the relaxation is less troublesome. 3.3 jfnk , jacobian-free newton-krylov, method a. presentation of the method in particular, it is the basis of the moose coupling platform [19]. the jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 199 jfnk is an implementation of newton's method based on a krylov method for solving linear systems, which is applied at each iteration of newton to the system 𝐽𝑥(𝑛) δx = -f (x (n) ). krylov's methods have the advantage of involving the system matrix only through matrix-vector products, which we are able to approximate by simple code calls. the jfnk method thus allows to define a sequential (codes are kept) but firm coupling technique. b. principle of krylov methods for solving ax = b let mbe the dimension of the vector b. krylov's methods consist in finding an approximation of the solution on a vector space kn of reduced dimension n ≤ m, which is constructed as follows: kn = vect(r0; ar0,..., a n-1 r0), where r0 = b ax0, with x0 an initial estimate of the solution of the linear system. in our case x0 is usually taken to be zero and we simply have r0 = b. to simplify the writings, we will work in the following directly with the variable b. note that (b, ab, ..., an-1 b) does not necessarily form a family of free vectors, but that if this is not the case, the solution x can be generated by the family (b, ab, ..., an-2 b). c. use and interest of the jfnk method in the context of coupling in a problem involving a jacobian, one can use the following taylor expansion to approximate the matrix-vector product: 𝐽𝑢 𝜈 = 𝐹(𝑢+𝜀𝜈)− 𝐹(𝑢) 2𝜀 + 𝑂(𝜀). (31) an evaluation of f corresponds to a call to the codes we couple. the method can therefore be used without the need to compute or store the jacobian of our coupled problem but requires frequent calls to the codes. we thus need one call of the codes per gmres iteration, in addition to the necessary call per newton iteration. we see that our approximation of the product 𝐽𝑢 𝜈 product introduces an error in o (𝜀). this error can be reduced by using a centered difference, but then we need two calls of the codes per iteration of gmres. 𝐽𝑢 𝜈 = 𝐹(𝑢+𝜀𝜈)− 𝐹(𝑢−𝜀𝜈) 2𝜀 + 𝑂(𝜀 2). (32) let us insist on the fact that the jfnk is only a way to implement newton's algorithm by circumventing the difficulties linked to the construction of the jacobian. newton's algorithm by circumventing the difficulties associated with the construction of the jacobian. the discussion about newton's method applies here. the jfnk introduces new parameters which are the 𝜀 used to calculate the product 𝐽𝜈 and the convergence criterion of the gmres method. the former must be chosen small enough to make the taylor expansion as fair as possible, but large enough to avoid numerical noise. the gmres convergence criterion is a compromise between accuracy and calculation time. 4. transient coupling methods 4.1. method directly derived from stationary techniques in the previous methods, the time variable does not intervene. we can then ask ourselves how to achieve a coupling in kinetics. to explain it, let us start by giving a general form of the coupling, as we did previously: { ∂x1 ∂t = g1 (x1 , x2 ) ∂x2 ∂t = g2 (x1 , x2 ) (33) except for very special systems, after choosing a numerical scheme, we obtain resolutions of the type: { 𝑥1(𝑡 + ∆𝑡) = 𝑥1(𝑡) + ℎ1(𝑥2(𝑡 + ∆𝑡), ∆𝑡) 𝑥2(𝑡 + ∆𝑡) = 𝑥2(𝑡) + ℎ2(𝑥1(𝑡 + ∆𝑡), ∆𝑡) (34) where the hi are continuous functions such that lim ∆𝑡→0 ℎ𝑖 (𝑥, ∆𝑡) = 0 ∀𝑥. by posing: { 𝐹1 (𝑢1, 𝑢2) = 𝑢1 − 𝑥1(𝑡) − ℎ1(𝑢2, ∆𝑡) 𝐹2 (𝑢1, 𝑢2) = 𝑢2 − 𝑥2(𝑡) − ℎ2(𝑢1, ∆𝑡) (35) we return to the form already studied: { 𝐹1 (𝑢1, 𝑢2) = 0 𝐹2 (𝑢1, 𝑢2) = 0 the methods already seen are therefore directly applicable, but we have an additional parameter that allows us to influence the strength of the coupling thus defined at each timestep: the time step itself. in particular, when using a gauss-seidel method, the convergence criterion (∃𝑀 < 1, ‖𝐽‖ ≤ 𝑀) is automatically verified for ∆t sufficiently small. unfortunately, the time step necessary for gauss-seidel is sometimes too small to be exploitable (calculation of the transient too long), and we then turn to the other methods already presented. let us note that there is a purely technical difficulty, but sometimes difficult to circumvent, for the implementation of evolving coupled schemes: the methods presented are iterative, it is thus necessary to be able to recalculate the same time step several times, without modifying the variables at the beginning of the time step (the 𝑥𝑖 (𝑡)in our notation). however, the codes sometimes forget 𝑥𝑖 (𝑡) during the calculation of 𝑥𝑖 (𝑡 + ∆𝑡). 4.2. explicit coupling to save calculation time when the couplings are weak, but also because of the technical difficulty we have just mentioned, it is often desired to calculate a transient coupled without iteration at each time step. to do this, we will look at how an error evolves during the calculation of a transient, whether or not the phenomenon being modelled arises from a coupling. let us write a general form for an evolution problem: 𝜕𝑥 𝜕𝑡 = 𝐹(𝑥). it is assumed that a classical explicit scheme is used, which gives us: x (t + ∆t) = x(t) + ∆t f (x(t)). (36) let us note 𝑥𝑒 the exact solution of the problem and suppose that at the 200 jean samon et al. /al-qadisiyah journal for engineering sciences 15 (2022) 192–201 beginning of the time step time step x(t) = 𝑥𝑒 (t) + 𝜀(t). we will also note 𝜀′ the error introduced by the scheme itself (which is of order 1 in time) on the time step we are calculating: 𝑥𝑒 (t) + ∆t f (𝑥𝑒 (t)) = 𝑥𝑒 (t + ∆t) + 𝜀′ (t + ∆t). (37) with this we have : x(t + ∆t) = 𝑥𝑒 (t) + 𝜀(t) + ∆t f (𝑥𝑒 (t) + 𝜀(t)) = 𝑥𝑒 (t) + 𝜀(t) + ∆t (f(𝑥𝑒 ( t)) + f(𝑥𝑒 ( t) + 𝜀 (t)) f(𝑥𝑒 ( t))) = 𝑥𝑒 (t + ∆t) + 𝜀'(t + ∆t) + 𝜀 (t) + ∆t (f (𝑥𝑒 ( t) + 𝜀 (t)) f (𝑥𝑒 ( t))) eq (38) thus we can write 𝜀(t + ∆t) = f(𝜀 (t)) with : f(u) = u + ∆t (f (𝑥𝑒 ( t) + u) f (𝑥𝑒 ( t)) )+ 𝜀'(t + ∆t) (39) as we move forward in time, the error committed evolves almost as if we were doing fixed point iterations with the function f thus defined. however, the equivalence is not perfect since 𝑥𝑒 and 𝜀′ evolve with time. to understand what is going on, let us suppose that these quantities are constant (which amounts to saying that we verify the stability of a stationary state), and that we are in one dimension. in this case, convergence occurs if |𝑓′(𝑢)| < 1, 𝑠𝑜𝑖𝑡 𝑠𝑖 𝐹′(𝑢) 𝜖 ] −2 ∆𝑡 , 0[ . the upper bound, f'(u) < 0, means that the system under study must itself be (statically) stable. as for the lower bound, we notice that by decreasing the time step it can be arbitrarily small. thus, with a sufficiently small-time step, the error committed by an explicit coupling scheme can remain bounded. nevertheless, the error committed is in o(∆t). the explicit scheme is therefore accurate to first order in time. the formalism used is valid when we evolve a coupled problem in time, and we do not converge the coupling at each time step. thus, the way in which the coupling is performed can reduce the accuracy of the solution to first order in time, even though the solvers themselves have better accuracy. this point is particularly important. by saving the work of thinking about the coupling scheme, one risks losing the benefit of all the work invested in the codes themselves. 5. synthesis the gauss-seidel method is very easy to implement and is the first method to be proposed in the genesis of coupling. this does not mean that the newton algorithm is superior in all respects to the gauss-seidel algorithm. the main advantage of newton's method is its quadratic rather than linear convergence speed. it is, therefore, to be preferred if a good coupling is desired. if one is simply interested in the solution of the coupled problem, the gauss-seidel algorithm is generally sufficient. the use of a relaxation, which can be determined empirically, is sufficient to make it very robust. only those cases, which are actually quite rare, where the algorithm diverges without oscillating cannot be stabilized with a relaxation. newton's algorithm, on the other hand, can be used theoretically on any case, but on condition that the initialization is good enough. even if the use of a relaxation is likely to greatly improve its behavior, the newton algorithm is sometimes less robust than the gauss-seidel algorithm, because it is more sensitive to noise. the comparative table summarizes our analysis by presenting the advantages and disadvantages of each method presented above. it shows that newton's method is the most appropriate for the coupling of disciplines in a mechatronic system. table1 table of methods with their advantages and disadvantages methods advantages disadvantages mechatronic systems direct methods suitable for medium and large sized systems. for large systems, it requires a lot of memory size. not adequate because there is no stability. gauss seidel methods suitable for linear systems and linear convergence. choice of the stopping condition. not adequate because mechatronic systems are linear. newton's methods appropriate for nonlinear systems and quadratically convergent. choice of initial data. adequate. jfnk method suitable for nonlinear systems, more memorable, includes more parameters which makes calculations easier. choice of initial data. adequate but with too many parameters. explicit pairing method time saving. reduced accuracy due to partitioned convergence. not adequate because poor precision emerges. 6. comparative table at the end of this coupling analysis, we have noticed that all systems, whatever the size, can be coupled by coupling methods. depending on the problem to be solved we have to choose the adequate method. direct methods if the system is of average size but also of large size while envisaging much memory size. hence the interest in using iterative methods, especially gauss seidel and jacobi. nevertheless, they are used for linear systems. however, mechatronic systems are non-linear. this justifies the choice of newton's method. therefore, for non-linear systems, we have to use the newtonian method while taking care to choose the initial data carefully. 7. conclusion at the end of this coupling analysis, we have noticed that all systems, whatever the size, can be coupled by coupling methods. depending on the problem to be solved we have to choose the adequate method. that is to say direct methods if the system is of average size but also of large size while envisaging much memory size. hence the interest in using iterative methods, especially gauss seidel and jacobi. 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https://www.nature.com/articles/s41567-020-0875-z#auth-alexandre_j_-kabla https://www.nature.com/articles/s41567-020-0875-z#auth-chwee_teck-lim https://www.nature.com/articles/s41567-020-0875-z#auth-chwee_teck-lim https://www.nature.com/articles/s41567-020-0875-z#auth-benoit-ladoux https://www.nature.com/articles/s41567-020-0875-z.pdf https://publications.polymtl.ca/8798/ al-qadisiyah journal for engineering sciences 13 (2020) 300–305 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: noora.alnafakh@student.uokufa.edu.iq (noor ali fakher) https://doi.org/10.30772/qjes.v13i4.689 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. influence of the number of reinforcement layers on the bearing capacity of strip foundation resting on sandy soil noor ali fakher a and mohammed kadhim fakhruldin a * a civil eng. depart., faculty of eng., university of kufa, najaf, iraq. a r t i c l e i n f o article history: received 3 september 2020 received in revised form 1 november 2020 accepted 1 november 2020 keywords: bearing capacity settlement geogrid a b s t r a c t reinforced soil technology is considered one of the most important methods of soil improvement due to its simplicity, easy implementation and saving cost. one of the known soil reinforcement methods is using geogrids to improve the bearing capacity of the soil and reduce the settlement of the soil beneath foundation. in this study, a strip foundation made of a rigid stainless steel with dimensions of 490 mm length, 135 mm width, and 40 mm thickness and reinforced with geogrid (called tensar ss2) was tested in a laboratory model to investigate the effect of the number of reinforcement layers on the bearing capacity and settlement. the soil was reinforced with one, two, three, and four layers of geogrid (tensar ss2). the obtained results showed that the reinforcement using geogrid system significantly improved the bearing capacity while reducing the settlement under the strip foundation compared with unreinforced soil. the test result also showed a good improvement in the bearing capacity when the number of reinforcement layers increased from one to four layers. the bearing capacity of the foundation increased when the soil reinforced by four layers of geogrid to about 2.5 times compared with the case of one layer of geogrid. in addition, the maximum settlement decreased to about 2.0 times compared with the case of one layer of geogrid. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction in order to achieve safe design of shallow foundation, it must be checked against two important characteristics. the first one is that the foundation should not exhibit exaggerated displacement or settlement, and the second is to ensure that the applied load does not yield shear failure omar et al. [1]. in ancient times, the sumerians used the soil in buildings using multiple methods. these methods vary depending on the nature of the building and its function. one of the important methods they considered was natural soil with other materials as a reinforcement such as straw to improve the soil. the ziggurat of agar-quf (3500 bc) is considered the first residual examples of a reinforced soil, as it was built using of the clay brick that were reinforced by utilizing of mats from woven reeds placed horizontally aswad [2]. many researchers have investigated the bearing capacity of geogrid reinforced foundation soils using experimental, analytical, and numerical methods. binquet and lee [3, 4] conducted the first parametric study that investigated the stability of soil layers mechanically to enhance the bearing capacity of shallow foundations [5, 6]. it was found from the previous experimental and numerical studies that the main factors affect the improvement of the bearing capacity are; the number of geogrid layers (n), depth of the upper layer (u), the type of geogrid, the soil properties, the vertical spacing of reinforcement (h), the maximum total depth of reinforced soil (d), and the effective length of reinforcements (b) [7-9]. it was also observed that the improvement in bearing capacity of reinforced soil by multi-layers of geogrid increased to about 7.0 times compared to the unreinforced soil al-sinaidi et al. [10]. in http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 302 noor ali fakher, mohammed kadhim fakhruldin /al-qadisiyah journal for engineering sciences 13 (2020) 300–305 current study, the main experimental program included bearing capacity and settlement tests by using strip footing models resting on reinforced sand with one, two, three, and four layers of geogrid (tensar ss2) in order to investigate the influence of the number of reinforcement layers. 2. material properties 2.1. sand sandy soil of al-najaf city was used in the current experimental investigation. physical, mechanical, and chemical tests were carried out to characterize the properties of this soil. these tests were the specific gravity, grain size analysis, maximum and minimum dry density, direct shear test and relative density. the chemical and physical features of the sand soil and the associated standards employed to do the tests are shown in the table 1. the grain size distribution has been analyzed in accordance with the astm d422 [11]. the particle size distribution curve of the soil material is displayed in fig. 1. the soil is classified as (poorly graded (sp) in accordance to the unified soil classification system (uscs) [12]. figure 1 grain size distribution curve of the sand. 2.2. geogrid in the present study, the geogrid tensar ss2 is used as a reinforcement. the geogrid was made by the british company netlon ltd. properties of the geogrid include physical and chemical characteristics. properties related to filtration, separation, drainage, and barrier applications are not including since the primary function of geogrids is reinforcement. table 2 shows the physical properties of the geogrid used in the present study, which tested by al-omari and fekheraldin [13]. table 1physical and chemical properties of the sand used soil property value standard effective size, d10 0.19 mm astm d 422 [11] d30 0.299 mm d50 0.39 mm d60 0.4 mm coefficient of uniformity (𝐶𝑢) 2.105 coefficient of curvature (𝐶𝐶) 1.176 specific gravity ( gs ) 2.61 astm d 854 [14] max. dry unit weight (𝛾𝑑𝑚𝑎𝑥) 17.658 kn/m3 astm d 4253 [15] max. void ratio,( 𝑒𝑚𝑎𝑥) 0.754 min. dry unit weight( 𝛾𝑑𝑚𝑖𝑛 ) 14.59 kn/m3 astm d 4254 [16] min. void ratio, (𝑒𝑚𝑖𝑛) 0.45 water content, % 6.56 astm d 2216 [17] relative density (𝐷𝑟 ) % 64 friction angle (𝜑 ø used) 35̊ satm d 3080 [18] dry unit weight used,(kn/m3) 16.4 organic material 1.4 bs.1377(1967) [19] gypsum content, % 2.70 t.d.s., (mg/l) 1150 3. experimental setups to assess the bearing capacity of the strip foundation models, an experimental investigation was performed using a physical model. fig. 2 shows the experimental setup used to carry out the tests, which consists of a container, strip foundation model, sand raining apparatus, and loading system. the strip footing model used in this study is made from a steel with a length of 490 mm, width of 135 mm, and thickness of 40 mm. the footing base model has been manufactured from a rigid stainless steel. the sand container has been made by fakhraldin [20] and has been used previously in many geotechnical problems . the inner dimensions of the box container are 1.0 m length, 0.5 m width and 0.7 m depth. the loading system consists of a manual hydraulic jack that is used to apply the load. the manual hydraulic jack can apply a maximum load of about 16 tons, where a load cell of a tension/compression is utilized to measure the loads, and three-dial gauges of 0.01 mm sensitivity, one situated at the center of the footing and the other 2 at counter-side corners of the footing at both sides have been utilized to assess the vertical displacement of the footing. 4. sand preparation the sand raining technique is utilized to fill the box with sand to the required level. the sand is permitted to rain through the air at a controlled rate of discharge and a specific height of pour to obtain homogeneity of sand formation and reconstruct the sand at the specified relative density turner et al.[21]. before depositing the sand in the tank, the raining system was calibrated by carrying out loops of trials with various dropping heights (10 cm, 30 cm, 40 cm, 50 cm, and 70 cm). these trials carried out to check and control the uniformity of the sand bed. the proportional height of pouring for any density of the sand deposition is obtained and presented in fig. 3. it is observed that the density of sand increases when the height of the pouring increases. from the graph in fig. 3, the dropping height can be directly found for any desired relative table 2 the physical properties of geogrid by al-omari and fekheraldin [13] properties unit data mesh type/color rectangle/black aperture size(md/xmd) mm 28/40 mass per unit area kg/m 2 0.3 rib thickness mm 1.2/1.1 junction thickness mm 3.9 peak tensile resistance kn/m 14.4/28.2 elastic modulus mpa 570/990 tensile strength mpa 24/30.7 percentage elongation at max load % 3.5/2.9 partial diameter (mm) 0 10 20 30 40 50 60 70 80 90 100 110 0.010.1110 f in e r (% ) noor ali fakher, mohammed kadhim fakhruldin /al-qadisiyah journal for engineering sciences 13 (2020) 300–305 303 density. the relative density selected in this study was 64% to study this phenomenon for medium sand, the required level proportional to achieve the desired density is 50 cm. the sand bed was prepared in six layers of 10 cm constant height of each layer to get the required height of 60 cm is measured from the bottom of the tank. the reinforcing material such as geogrid is put at the desired depth and the tank is filled up with sand with the assistance of the funnel. the sand surface at the depth is graded through of a straight edge before placing the geogrid (the reinforcing material). figure 2 experimental set-up. 5. geogrid preparation fig. 4 illustrates the cross-sectional display of the model of the tank and the model of the footing with soil system having four layers of the tensar ss2 reinforcement. a model strip footing with a width (b) is supported by the sand reinforced with (n) number of geogrid layers having a width "b". the vertical distance between successive layers of the geogrid tensar ss2 is "h". the upper stratum of the geogrid is situated on a depth distance of "u" calculated from the footing model base. the following equation has been used to measure the reinforcement depth (d) beneath the foundation bottom: d = u + (n − 1) * h. a value of u of 0.25 b is employed based on the findings of other researchers as being the best to give higher bearing capacity [1]. the distance between reinforcement layers (h) is considered equal to 0.1875 b as suggested by fakhraldin [20]. by analyzing several test results and taking into account the prior results [1, 20], it is decided to take the following parameters in this research: u/b = 0.25; h/b = 0.1875; the geogrid stratum number (n): 1, 2, 3, and 4. figure 3 density calibration figure 4 layout of geogrid spacing in cross section. 6. testing program the inner face of the test tank was made smooth by the lubrication system to decrease the influence of the side friction on the load measurements fakhraldin [20]. in every test, the foundation was loaded accumulatively until the failure occurred. the vertical load was transmitted axially to the foundation through the manual press. the load was viewed from the digital weighing indicator attached to the load cell; every load increase is maintained constant until the settlement is stabilized. initially, the soil reinforced by a single layer was tested. the first geogrid layer was positioned carefully on the distance equal to 0.25b from the surface of the sand. for two layers of reinforcement, after filling the tank with sand to a defined position (i.e. height of the sand), the two layers of reinforcement were placed at a distance equal to 0.185b from one layer reinforced sand. after that, the raining of sand was continued to fill the tank. when the required level of sand was reached (at the base of the foundation model), the sand raining was stopped, and the raining box was removed. the procedure described above was also used for three and four layers of reinforcement. the third layer was put at a distance adjusted to 0.185b under the second layer of reinforcement and the fourth layer was put at a distance adjusted to 0.185b below the third layer. the strip foundation is placed with care in models to minimize the change in the relative density loading system soil container dial gauge load cell height (cm ( r e la ti v e d e n si ty ( % ) 304 noor ali fakher, mohammed kadhim fakhruldin /al-qadisiyah journal for engineering sciences 13 (2020) 300–305 and to avoid disturbance to eventually ensure consistent density for all tests. the average vertical settlement was calculated utilizing three-dial gauges of 0.01 mm accuracy and 50 mm is the maximum capacity of dial gauge at three different locations on the surface of the foundation, one positioned on the center of the footing and the other two, at opposite corners of the footing at both sides. a magnetic holder was used to fix the dial gauge on the loading frame. an experimental program was introduced to assess the influences of the relative density on the settlement and bearing pressure of the foundation subjected to vertical loads. 7. discussions the results the static loading tests were performed to determine the ultimate bearing capacity and load-settlement relationship for strip footing with one, two, three, and four reinforced layers by geogrid tensar ss2 at 64% relative density. the load settlement curves obtained from the tests are plotted in fig. 5 with multiple numbers (1, 2, 3, and 4) of geogrid layers. from the load-settlement curve shown in fig. 5, the ultimate load carrying capacity of sand at a relative density of 64% is calculated with varying number of geogrid layers. the ultimate bearing capacity for each model was determined by using vesic method, which is the peak load obtained from the load settlement curve of each model vesic et al. [22]. the ultimate bearing capacity of sand reinforced by 1, 2, 3, and 4 layers of geogrid tensar ss2 were 145.33 kpa, 167.57 kpa, 236.78 kpa, 358.86 kpa, respectively. from the above test results, it is observed that the bearing capacity of sand was increased after sand reinforced by four layers of geogrid to about 2.5 times the reinforced sand's bearing capacity by one layer of geogrid. the results obtained from the tests in reinforced sand by one, two, three, and four layers of geogrid tensar ss2 are shown in fig. 6. it is easy to observe that the bearing capacity increases when the number of reinforcement layers increases. the ultimate bearing capacity values obtained from the work tests and the maximum settlement are presented in table 3. figure 5 load –settlement curve figure 6 effective of number of layers on bearing capacity 8. conclusions in this study, a special experimental program was designed to study the influence of the number of reinforcement layers bearing capacity and settlement of strip footing models resting on sand reinforced by geogrid (tensar ss2). depending on the tests’ results of this experimental study, the following conclusions can be deduced: 1. the bearing capacity of sand increased after sand reinforced by four layers of geogrid to about 2.5 times the case of one layer of geogrid. 2. the settlement is generally found to decrease when the number of reinforcement layers increased, the maximum settlement for forth layers of tensar ss2 decreased to about 2.0 times the maximum settlement of one layer of geogrid. references 1. omar, m., et al., ultimate bearing capacity of shallow foundations on sand with geogrid reinforcement. canadian geotechnical journal, 1993. 30(3): p. 545-549. 2. aswad, m.f., the effect of reinforcement material -nylonon sandy soil behavior under foundations”, thesis presented to university of technology., in partial fulfillment of the requirements for the degree of master in civil engineering. 1989. 3. binquet, j. and k.l. lee, bearing capacity tests on reinforced earth slabs. journal of geotechnical and geoenvironmental engineering, 1975. 101(asce# 11792 proceeding). 4. binquet, j. and k.l. lee, bearing capacity analysis of reinforced earth slabs. journal of geotechnical and geoenvironmental engineering, 1975. 101(asce# 11793 proceeding). 5. alamshahi, s. and n. hataf, bearing capacity of strip footings on sand slopes reinforced with geogrid and grid-anchor. geotextiles and geomembranes, 2009. 27(3): p. 217-226. 6. chen, q. and m. abu-farsakh, ultimate bearing capacity analysis of strip footings on reinforced soil foundation. soils and foundations, 2015. 55(1): p. 74-85. 7. vito, a.g., biesiadecki, g.l.,sullivan, m.j., bearing capacity of th geotextilereinforced foundation. 11th international conference on soil mechanics and foundation engineering, san francisco, 1985. 112: p. 53-60. table 3 the ultimate bearing capacity and maximum settlement. number of layers(n) (qult) r kpa max. settlement (mm) improvement in b.c (%) decrease in settlement (%) 1 145.33 20.52 2 167.57 25.54 1.153 1.0715 3 236.78 27.32 1.629 1.3689 4 358.86 27.02 2.469 2.083 (qult) r : the ultimate bearing capacity of reinforced sand b.c : bearing capacity settlement (mm) b e a ri n g p re ss u re ( k n /m 2 ) 0 50 100 150 200 250 300 350 400 0 5 10 15 20 25 30 35 n=1 n=2 n=3 n=4 b e a ri n g c a p a c it y ( k n /m 2 ) number of layers (n) 145.33 167.57 236.78 358.86 0 50 100 150 200 250 300 350 400 1 2 3 4 1 2 3 4 noor ali fakher, mohammed kadhim fakhruldin /al-qadisiyah journal for engineering sciences 13 (2020) 300–305 305 8. haripal, p., r. behera, and c. patra, behavior of surface strip footing on geogrid reinforced sand bed. international association for computer method and advance in geomechanics, india, 2008. 9. phanikumar, b., r. prasad, and a. singh, compressive load response of geogrid-reinforced fine, medium and coarse sands. geotextiles and geomembranes, 2009. 27(3): p. 183-186. 10. al-sinaidi, a.r. and a.h. ali, improvement in bearing capacity of soil by geogrid-an experimental approach. iaeg2006, united kingdom, 2006. 11. astm, astm d422-63: standard test method for particle-size analysis of soils. 2007, astm international west conshohocken^ epa pa. 12. standard, a., d2487–06, 2006, tandard practice for classification of soils for engineering purposes (unified oil classification ystem). annual book of astm standards, american society for testing and materials, west conshohocken, pa. 13. fekheraldin, r.r.a.-o.m.k., measurement of tensile properties of geogrids. environment, kuala lumpur, malaysia, 2012. 14. astm, d., standard test methods for specific gravity of soil solids by water pycnometer. d854, 2010. 15. astm, standard test methods for maximum index density and unit weight of soils using a vibratory table. 2006. 16. astm, d., standard test methods for minimum index density and unit weight of soils and calculation of relative density. 2006, west conshohocken pa. 17. astm, d., standard test methods for laboratory determination of water (moisture) content of soil and rock by mass. 2010, astm west conshohocken, pa. 18. d3080-1998, a., standard test method direct shear test. 1998, astm. 19. bs 812 and i. 19.020, testing aggregates. method for determination of sulphate content, manual 895/2003. 20. fakhraldin, m., properties measurements and applications of some geogrids in sand. 2013, phd thesis, alnahrain university. 21. turner, j. and f. kulhawy, experimental analysis of drilled foundations subjected to repeated axial loads under drained conditions. report el-s32s, electric power research institute, palo alto, california, 1987. 22. vesic, a.s., analysis of ultimate loads of shallow foundations. journal of soil mechanics & foundations div, 1973. 99(sm1). article al-qadisiyah journal for engineering sciences 14 (2021) 123–133 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohanad.shallal@qu.edu.iq (muhaned a. shallal) https://doi.org/10.30772/qjes.v14i2.760 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. temperature change in steel-concrete composite bridge: experimental and numerical study maryam salim.a.a, muhaned a.shallal a* a departement of civil engineering, college of engineering, university of al-qadisiyah, iraq. b university of al-qadisiyah collage of engineering, iraq. a r t i c l e i n f o article history: received 29 june 2021 received in revised form 10 august 2021 accepted 11 august 2021 keywords: composite bridge; solar radiation; finite element analysis; air temperature; temperature distribution. a b s t r a c t in this article, a prototype empirical section of the composite girder was performed to verify the temperature distributions and the changes in concrete bridges under environmental thermal stresses. tbeam composite section was placed directly subjected to environmental conditions to endure the change in convection, the convection includes solar radiation, surrounding air temperature and wind speed. in addition, this paper includes the 3d finite-element thermal studies represented by the comsol multiphysic program, with particular reference to the influence of several parametric studies that represented by changing in concrete thickness, adding asphalt layer and finally change the value of wind speed. the section is prepared with fifteen thermocouples in different places in steel and concrete in the actual and theoretical model to evaluate the temperature distribution inside the composite bridges and their effects in the selected points. comsol multiphysic showed a good ability to simulate convection, heat conduction and radiation within the surrounding environment. such as thermocouple (tc3) the minimum temperature was 33.18 oc, 33.29 oc, the maximum temperature was 63.67 oc, 62.77 oc for experimental and theoretical results respectively while the maximum and minimum difference between experimental and fe temperatures is 2.96 and 0.099 for tc3 respectively. therefore, it can be said that all the thermocouples results showed a good agreement between practical and theoretical results. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction continuous bridges girders undergo frequent heating and cooling cycles from the environment that represented by sun radiation, surrounding air temperature and these conditions produce thermal stresses. thermal stresses effects have often been related to damage of steel-concrete bridge girders. the nonlinear temperature distributions that stand up in bridges are not effortlessly anticipated and are often taken into consideration in a simplified manner, which can also cause structural behavior troubles[1, 2]. exposed structures, for example, bridges, are constantly heat loss and gain from sun radiation, convection and returning radiation to and from the surrounding air, which causes the difference in average bridge temperature and non-linear temperature distributions alongside the depth and the width of the structure[3, 4]. depending on the end situations of the girder, these temperature variations and gradients can also cause longitudinal enlargement and shrinkage and the thermal loads caused stresses in http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 124 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 directions perpendicular to the longitudinal axis. so that, the temperature variant can purpose critical cracking and deflections[4–7].to calculate temperature gradients in composite bridge girders, the quantity of solar radiation absorbed from the surface, the value of wind speed and the air temperature has to be recognized. the quantity of absorbed solar radiation is a function of the surface sun energy absorption. wind speed, bridge route and geometry are key elements. many studies on the impact of wind speed [2, 8], bridge route [2, 9, 10] and geometric formation[2, 9, 11] had been found in the present-day literature, even as exact parametric studies the effect on temperature differences and distributions were found in concrete –steel girder. the purpose of this study is to show the result of the experimental study, results of the theoretical study by using comsol multiphysic program and a comparison between practical and theoretical results and finally using several parametric to study the combined effect of changing concrete slab, adding asphalt layer and change the value of wind speed on the temperature gradients in concrete bridges. 2. experimental work experimental works included casting a segment of composite concretesteel. fig.1 shows the dimensions and locations of thermocouples in the composite bridge section. the steel beam depth is 500 mm, the width of the flange is 250 mm and the thickness of the web and flange is 8 mm. experimental work includes welding i-steel beam in distinct dimensions and with 8 bolts that had been used as shear connectors. after that, the plywood had been used to make the framework of the concrete slab. the thermocouples sensor is used in this section to degree the temperature distribution and its effect on composite bridge at certain points and the entire number of thermocouples that have been used was (15), (7) in concrete and it symbolizes by (tc), (7) in steel and it symbolizes by (ts) and one between them is symbolized by (tcs). finally, the concrete was poured as shown in fig.2, aspects of concrete slab and steel completely secluded through the use of foam to make the sample as an internal bridge and prevent switching heat from those faces as shown in fig.3. figure 1. dimensions and thermocouples locations. figure 2. specimen after casting. figure 3. secluded the sides of specimen. 3. experimental results 3.1. environmental results: the environmental data were including measure three factors during july 24 that represent the summer season (sun radiation and daily air temperature are high in this season so; the temperature variance is high and clear). the first factor was surrounding air temperature, its essential in analysing the thermal behaviour of the model because it impacts the radiance of the exterior surface of the surrounding and the convective refrigeration over daylight hours. fig.4 shows the behaviour of the surrounding air temperature. the second factor was solar radiation and which indicate the external heat source. fig.5 indicates the sun radiation throughout 24-july. the most crucial factor affecting surface refrigeration by convection was wind speed, so the value must be known to take a look at the temperature gradients all through the day. fig.6 shows the wind speed in the course of 24-july. nomenclature c specific heat (j kg-1 k-1) greek symbols k thermal conductivity (w m-1 k-1)  density (kg m -3) 1000 mm 5 0 0 250 tc1tc2 tc3 tc7 tc12 tc6 tcs13 tc4tc5 ts8 t s 9 t s 1 0 t s 1 1 ts14 ts15 1 0 0 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 125 figure 4. ambient air temperature during 24-july. figure 5. solar radiation during 24-july. figure 6. wind speed during 24-july 3.2. temperature variance four thermocouples are used in this article to show the experimental results two thermocouples are used in concrete (tc3and tc12) and two in steel (ts9 and ts11). in general, fig.7 & fig.8 show the temperature variance in concrete during the sunny day (24 july). the figures show the clear variance is during the sunny day (24 july). table 1 indicates the maximum and minimum recorded temperature distribution for tc3&tc12. figure 7. temperature change in (tc3) thermocouple during a sunny day. figure 8. temperature change in (tc12) thermocouple during a sunny day. table 1. minimum and maximum temperatures 24-july for tc3 and tc12. thermocouple minimum temperature (c) maximum temperature (c) tc3 33.14 63.77 tc12 31.83 66.77 126 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 while fig.9 & fig.10 show that, the thermocouple in steel have jumps and these jumps came when the solar radiation becomes horizontal and falling directly on the steel section. table 2 showed the maximum and minimum temperature distribution for ts9& ts11. figure 9. temperature change in (ts9) thermocouple during a sunny day. figure 10. temperature change in (ts11) thermocouple during a sunny day. table 2. minimum and maximum temperatures 24-july of thermocouple in steel. thermocouple minimum temperature (c) maximum temperature (c) ts9 33.95 60.64 ts10 34.2 63.22 4. finite element approach comsol multiphsicycs mussa et al. [4] finite element software version 5.5 was used to study thermal transfer analysis of temperature on the girder of a steel-concrete-composite bridge (t-beam) for a sunny day fig.11 shows the mesh of composite bridge segment and fig.12 shows the definition of solar location with respect to composite segment . it was assumed that the material properties that were used in the finite element analysis are isotropic and time-independent. from previous studies emanuel et al. [12], the material properties were set, so that the specified values could efficiently simulate the real heat transfer technique. the concrete material properties are density ρ = 2400 (kg/m3), thermal conductivity k = 1.5 (w/m.k), and heat capacity at constant pressure (specific heat) c = 900 (j/kg.k). steel material properties are density ρ = 7850 (kg/m3), thermal conductivity k = 44.5 (w/m.k), and heat capacity at constant pressure (specific heat) c = 475 (j/kg.k). apply air temperature, wind speed, and vertical and horizontal solar radiation at a distinctive time to represent the initial temperature of the entire bridge body at the start of the fe analysis procedure. the analysis was started 24 hours before the scheduled time to decrease the effect of the initial temperature on the solution and to avoid error in the comsol program. figure 11. the mesh of composite bridge segment. figure 12. the definition of solar location with respect to composite segment. 4.1. comparison between practical and numerical results the chosen day, july 24, 2020, is used to conduct a comparative study of the temperatures recorded from the experimental composite steel bridge girder section and the temperatures predicted from fe thermal analysis. four thermocouples are used to show the experimental and theoretical results, two thermocouples are used in concrete (tc3and tc12) and two in steel (ts9 and ts11). in general, fig.13 to fig.16 shows the result of the tc3, tc12, ts9 and ts11 thermocouples that showed a good match between the maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 127 experimental temperature result and the finite element temperature result. for this reason, it can be concluded that the fe model is effective. the tc3 and tc12 thermocouples located in the middle concrete slab and the top of the concrete slab respectively, fig.13 and fig.14 illustrate the comparison between the experimental results and the finite element results. from this figure, the general behaviour of the time-varying temperatures was nearly identical between the experimental results and the fe results. table 3 shows a compare of the minimum and maximum temperatures for sunny days (july 24) for these thermocouples. the maximum difference between experimental and fe temperatures is 2.96 and 2.34 for tc3 and tc12. figure 13. hourly experimental recorded and fe expected temperatures at tc3 thermocouple of composite segment. figure 14. hourly experimental recorded and fe expected temperatures at tc12 thermocouple of composite segment. table 3. minimum and maximum temperatures 24-july for tc3and tc12. thermocouple min. temperature (c) experimental fe max. temperature (c) experimental fe tc3 33.18 33.29 63.67 62.77 tc12 32.41 33.74 66.2 65.80 the thermocouples ts9 and ts11 located in the steel web also in different places, fig.15 & fig.16 indicates the comparison between the experimental results and the results of fe. the general behavior of the figures showed a good match between practical and theoretical results. table 4 shows a comparison of the minimum and maximum temperatures for sunny days (july 24) for these thermocouples. the maximum difference between experimental and fe temperatures is 1.78 and 2.54 for ts9 and ts11. figure 15. hourly experimental recorded and fe expected temperatures at ts9 thermocouple of composite segment. figure 16. hourly experimental recorded and fe expected temperatures at ts11 thermocouple of composite segment. table 4. minimum and maximum temperatures 24-july of thermocouple in steel. thermocouple min. temperature (c) experimental fe max. temperature (c) experimental fe ts9 32.12 31.51 57.09 56.05 ts11 34.34 33.54 61.95 60.72 128 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 5. parametric study several parametric studies were performed to verify the effects of concrete slab thickness, change the value wind and using an asphalt layer on the temperature distribution of the composite section. presumably, the studied bridges are located in diwaniyah, iraq (32 00n, 4455e). two days were chosen to study the various parametric studies, and these days represent the extremes of weather conditions (24 july 2020 and 15 january 2020), and the same weather data obtained from the experimental work for these days were adopted. for all parametric studies, the average wind speed value was used which is equal to 1.232 (m/s) for the winter and it is equal to 1.712 (m/s) for the summer. areal part of one of the spans inside the abu al fadl bridge, as shown in fig. 17, was approved in the city of diwaniyah, to study the effect of parametric studies on temperature change. figure 17. dimensions of the bridge section. 5.1. effect of slab thickness concrete slab thickness in composite bridges is an important factor affecting the temperature gradient within the segment. to study the effect of this parameter, four values were chosen to represent the thickness of the concrete slab 150, 200, 250, 300 mm, with no change in steel dimension. fig.18 show the temperature change during the day at the upper surfaces of the concrete on a hot day (july 24) and cold day (january 15) respectively. from fig.18 it can be seen that the temperature of the upper surface is not affected by the change in the thickness of the concrete slab on summer and winter days, because of changing in concrete thickness does not effect on the amount of energy exchanged between the upper surface and the surrounding atmosphere. fig.19 shows an increase in the effect on the temperature of the bottom surface when the thickness of the concrete slab decreases on a hot day, while this effect decreases on a cold day, and the reason is due to the closing of the distance between the two. so the lowest concrete surface is affected more than other surface. the difference in surface temperature and temperature in the concrete core is an important factor in determining the temperature distribution. fig.20 indicates the effect of the change in thickness on the difference between upper surface temperature and temperature at 60 % and 80% from depth of concrete slab thickness on a hot and cold day (24 july, 15 january). from fig.20, the maximum temperature differences are on 24july 15.44 c, 18.29 c, 20.48 c, and 22.34 c, and occurs between 12:00 and 12:45, the temperature extremes were from january 15 are 4.27 °c, 4.49 °c, 4.77 °c, and 5.10 °c, and occurred between 14:00 and 14:30 for the thickness of 150, 200, 250, and 300 mm straight. the minimum temperature differences on july 24 were 2.37 °c, 3.23 °c, 4.04 °c and 4.70 °c and occur between 0:00 and 4.30 for thicknesses of 150, 200, 250 and 300 mm, respectively for 60%from concrete depth. while for 80% from concrete, in fig. 21 the temperature extremes are from july 24 to 18.09 °c, 20.60 °c, 22.34 °c, and 24.09 °c, and occur between 12:00 and 12:45 for the thickness of 150, 200, and 250, and 300 mm, respectively. the temperature extremes were from january 15 to 4.82 °c, 5.21 °c, 5.50 °c and 5.85 °c, and occurred between 14:00 and 14:30 for thicknesses of 150, 200, 250, and 300 mm straight. the minimum temperature differences on july 24 were 1.49 °c, 1.99 °c, 2.41 °c and 2.91 °c, and occurred between 0:00 and 4.30 for thicknesses of 150, 200, 250 and 300 mm, respectively. the differences in minimum temperatures on january 15 were 1.26 °c, 1.89 °c, 1.95 °c, and 2.66 °c, and occur at 5:15 pm for thicknesses of 150, 200, 250 and 300 mm, respectively. from the above data for the two figures, a set of observations can be recorded, where the temperature difference rises with the rises in the thickness of the slab, and the maximum difference occurs on a hot day (july 24) at 12:00 noon, as well as the minimum difference that occurs on the same day. figure 18. effect of slab thickness on the top surface temperature in 24-july and 15-january. figure 19. effect of slab thickness on the bottom surface temperature in 24-july and 15-january. maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 129 figure 20. effect of thickness on the variance between the upper surface temperature and the temperature at a depth of 60% of the slab thickness. figure 21. effect of thickness on the variance between the top surface temperature and the temperature at a depth of 80% of the slab thickness. fig.21 shows the temperature gradients is linear and positive between the top surface and 80% of the concrete slab thickness, at the same time as its miles negative between the bottom surface and 80% of the concrete slab thickness. fig.22 indicates that the reversed temperature distribution is concave, and the temperatures of the upper and lower surfaces are approximately identical. table 5 shows the effect of slab thickness at the maximum and minimum average temperature of the composite bridge. the maximum temperature became recorded on july 24 between 14:30 and 15:30, whilst the minimum average temperature turned into recorded on january 15 at 15:15. the distinction between the maximum and the implied minimal temperature is 54.84 ° c, 51.80 ° c, 49.48 ° c, and 47.61 ° c for the thickness of the slab is 150, 200, 250, 300 mm respectively. figure 22. thickness effect on temperature gradient at 12:00 hr at (24-july). figure 23. thickness effect on temperature gradient at 0:00 hr at (24-july). table 5. effect of slab thickness on the maximum and minimum average temperature of the composite bridge. thickness (mm) maximum (c) time (hr) minimum (c) time (hr) range (c) 150 59.69 14:30 4.85 5:15 54.84 200 57.57 14:45 5.77 5:15 51.80 250 55.97 15:00 6.49 5:15 49.48 300 54.63 15:30 7.02 5:15 47.61 5.2. effect of asphalt thickness several parametric studies are performed to discuss the effects of the varying convection. one of these parameters was the effect of the asphalt layer. the different values thickness of the asphalt were used and these values were 0, 6 and 10 cm. zero value of asphalt layer thickness means no asphalt layer, concrete slab is the surface exposed to solar radiation. 130 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 the properties of asphalt material are solar absorption coefficient a = 0.92, density ρ = 2100 (kg / m3), thermal conductivity k = 1.1 (w /m.k), specific heat c = 920 (j / kg. k), and emissivity coefficient (ɛ = 0.93). fig.24 shows the temperature difference of the top surface of the concrete. in summer, it can be seen that the temperatures of the top surface of the sample, which is 6 cm thick, are approximately the same as that of the sample not covered by asphalt, with a time difference between the two curves. the temperatures of a sample covered with asphalt with a thickness of 10 cm are lower than other samples. the reason is due to the greater depth of asphalt compared to another sample which means that the amount of heat that reaches the surface of the concrete is less compared to the sample that has a thickness of 6 cm. during the night, samples covered with asphalt retain heat compared to sample without asphalt, as the upper surface is not subjected to direct cooling at night. in winter, the effect is almost negligible, and the reason is the small amount of solar radiation during this period of the year. fig.25 and fig.26 show the temperature gradients with the depth of the bridge installed at 15:00 and 1:00, respectively. fig.25 indicates the temperature difference inside the concrete slab ranges from approximately 0.5 to 3 °c when comparing the sample covered with a 6 cm asphalt layer with the reference sample (without the asphalt layer), while the difference is greater when comparing the reference sample with the sample covered with an asphalt layer 10 cm long. fig.25 shows that the temperature difference is concentrated inside the top of the concrete slab. this difference is limited when the sample covered with a 6 cm asphalt layer is compared with the reference sample (without the asphalt layer), while the difference is clear and tangible when comparing the reference sample with the sample covered with a layer asphalt 10 cm long. fig.26 indicates the effect of adding an asphalt layer on the maximum and minimum average temperature of the composite bridge. table 6 shows the average maximum and minimum temperatures for the composite bridge for the different asphalt layers. the differences between the maximum and minimum average temperatures decrease slightly with the increase in the thickness of the asphalt layer. figure 24. effect of asphalt layer thickness on the temperature of the concrete top surface. figure 25. effect of asphalt layer thickness on the temperature distribution with depth of the composite bridge at hr=15:00. figure 26. effect of asphalt layer thickness on temperature distribution with depth of the composite bridge at hr=1:00. these results are in accordance with the british standard bs 5400-2 [13], where the presence of an asphalt layer with a thickness of 100 mm reduced the differences between the maximum and minimum average temperatures to 3 °c, while the results of the current study showed the difference between the maximum the minimum average temperature is 4.18 °c for the same thickness (100 mm). aashto [14] considered that these differences due to the asphalt layer are small and can be neglected. fig. 27 shows the eeffect of asphalt layer on the maximum and minimum average temperature of the composite bridge. table 6. effect of asphalt layer on the maximum and minimum average temperature of the composite bridge. asphalt thickness (mm) maximum (c) time (hr) minimum (c) time (hr) range (c) 0 55.97 12:45 6.49 5:15 49.48 60 54.92 15:15 6.83 5:30 48.1 100 53.02 15:45 7.72 5:30 45.3 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 131 figure 27. effect of asphalt layer on the maximum and minimum average temperature of the composite bridge. 5.3. effect of wind speed the third parameter was to study the effect of wind speed on the temperature gradient. wind speed affected on the heat transfer coefficient (hc). three different values of wind speed were used and these values are 0, 2 and 4 (m/s). fig.28 and fig.29 shows the effect of wind speed on the temperature change of the top and bottom surface of the concrete slab on (july 24). from the figure it can be seen that the temperature decreases with increasing wind speed where the maximum difference in temperature is 7.78 and 12.60 ° c for upper surface and the difference for lower surface was 2.76 c and 3.67  when comparing the temperature curves of wind speed 2 and 4 (m/s) with the wind speed curve temperatures equal to zero, respectively. the maximum differences between the temperatures curves were appear 15.45 for the top and appear at sunset for bottom surface.fig.30 shows the impact of wind speed on the temperature gradient of the composite bridge at 14:00 (july 24). from this figure, it could be observed that the maximum difference between the temperature curves occurs at the top surface of the concrete slab, and the temperature gradient will increase with the decrease in the wind speed. fig.31 shows the effect of wind speed on the average maximum and minimum temperature of the composite bridge, while table 7 shows the average maximum and minimum temperature of wind speed 0, 2 and 4 m / s. from the above figure and table, it could be observed that the wind speed has no effect in the winter season, but in the hot season, the wind speed is influential in the maximum mean temperature as the average temperature decreases with increasing wind speed. table 7. effect of wind speed on the maximum and minimum average temperature of the composite bridge. wind speed (m/s) maximum (c) minimum (c) range (c) 0 59.86 6.55 53.13 2 55.94 6.44 49.05 4 52.64 6.43 46.21 figure 28. effect of wind speed on the temperature variation of the top surface concrete slab on a summer day (24-july). figure 29. effect of wind speed on the temperature variation of the bottom surface concrete slab on a summer day (24-july). figure 30. effect of wind speed on the temperature gradient in composite section on a summer day (24-july @ 14:00). 132 maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 figure 31. effect of wind speed on the maximum and minimum average temperature. 6. conclusion based on the data estimated from the composite section analysis under the environmental conditions of iraq weather using the comsol multiphysics program and from the practical results, the following conclusions can be drawn: 6.1. experimental conclusions 1. the maximum air was 50.03 oc while the daily minimum value was 4.09 oc so, the difference between the two values was, 45.94 oc. the maximum solar energy of 24july was 980 (w/m2), while the minimum sun radiation was appeared in cold day and its value was 498.7 (w/m2) 2. the temperature variance is clear during the hot day (24 july) 3. the thermocouple within the steel segment has jumped within the measured temperature, and this temperature increase is throughout the duration of sunrise and sunset due to the exposure of the steel section to direct sunlight. 6.2. the numerical conclusions 1. the fe model using comsol multiphysis of the composite section showed good ability to simulate convection, thermal conductivity and radiation within the surrounding environment. therefore, the thermocouples showed good agreement between fe and the experimental results. 2. the numerical study showed that the thickness of the concrete slab has no effect on the temperature of the top surface, while the effect of the thickness of the concrete slab is noticeable on the temperatures of the bottom surface of the concrete slab and the temperatures inside the concrete slab. 3. existing asphalt layer leads to an increase in the solar energy gained during the day due to the black color of the layer, but on the other hand, the presence of the asphalt layer with a certain thickness will lead to lower temperatures at the bottom surface of the asphalt layer, so the presence of a medium thickness layer (50 or 60 mm) has a slight effect on the temperatures of the top surface of the concrete slab during the day while the increase in thickness of this layer leads to a decrease in the temperature of the top surface of the concrete. 4. during the day, when comparing the top surface temperature of a composite segment without asphalt layer with the compound section of asphalt layer thickness of 60 mm, the temperature difference is less than 2 °c, while when the layer thickness is 100 mm, the difference is more than 9 °c. while at night, noticed the opposite, as the temperatures are hotter when there is an asphalt layer and the temperature increase during this period with the increase in the thickness of the layer as a result of not cooling the concrete surface by wind when covering the concrete surface with an asphalt layer 5. increasing wind speed cools the surface, and vice versa. the maximum temperature difference of the upper concrete surface is 7.78 and 12.60 °c when comparing the temperature curves of the wind velocity of 2 and 4 (m/s) with the wind velocity curve temperatures equal to zero, respectively. the influence of wind speed is less on other areas of the compound section. 6. from the parametric study the maximum effect can be obtained during the hot day when the solar energy absorbed by the concrete surface is higher while the steel part is shaded by the overhanging parts, the wind speed is lower, and the air temperature range is high. based on these conditions, an effective temperature of 60 ° c may be recommended for bridges whose concrete slab thickness is 200 mm or less. while for bridges with concrete slab greater than 200mm, 55 °c is recommended as the effective temperature. references [1] r. a. imbsen, d. e. vandershaf, r. a. schamber, and r. v. nutt, thermal effects in concrete bridge superstructures., (3). washington, dc., 1985. [2] m. m. elbadry and a. ghali, temperature variations in concrete bridges, journal of structural engineering, 109(10) (1983) 2355–2374. [3] g.-d. zhou and t.-h. yi, thermal load in large-scale bridges: a state-ofthe-art review, international journal of distributed sensor networks, 9(12) (2013) 217983. [4] f. mussa, s. r. abid, and n. tayşi, winter temperature measurements in a composite girder segment, iop conference series: materials science and engineering, 888 (2020) 012074. [5] p. d. krauss and e. a. rogalla, transverse cracking in newly constructed bridge decks, (1996) 132. [6] m. elbadry and a. ghali, control of thermal cracking of concrete structures, aci materials journal, 92(4) (1995) 435–450. [7] m. elbadry and a. ghali, thermal stresses and cracking of concrete bridges, aci journal proceedings, 83(6) (1986) 1001–1009. [8] b. wang, w. wang, and x. zeng, measurement and analysis of temperature effects on box girders of continuous rigid frame bridges, world academy of science, engineering and technology, 46(10) (2010) 731–737. [9] w. h. dilger, a. ghali, m. chan, m. s. cheung, and m. a. maes, temperature stresses in composite box girder bridges, journal of structural engineering, 109(6) (1983) 1460–1478. [10] c. w. roeder, thermal movement design procedure for steel and concrete bridges .report to the national cooperative highway research program, (april). washington, d.c., 2002. [11] d. li, m. a. maes, and w. h. dilger, thermal design criteria for deep prestressed concrete girders based on data from confederation bridge, canadian journal of civil engineering, 31(5) (2004) 813–825. maryam salim.a., muhaned a.shallal /al-qadisiyah journal for engineering sciences 14 (2021) 123–133 133 [12] j. h. emanuel and c. m. taylor, length-thermal stress relations for composite bridges, journal of structural engineering (united states), 111(4) (1985) 788–804. [13] british standards institution bsi, steel, concrete and composite bridges part 2. specification for loads, bs 5400-2: (2006) 32–34. [14] aashto, aashto lrfd bridge design specifications, 8th edition table of contents and introduction, (2017). article al-qadisiyah journal for engineering sciences 15 (2022) 218–223 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: khalida.k.mansour @uotechnology.edu.iq (khalida kadhim mansor) https://doi.org/10.30772/qjes.v15i4.854 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. numerical and experimental analyzes of forming parameters of low carbon steel khalida kadhim mansor department of production engineering & metallurgy, university of technology, baghdad, iraq a r t i c l e i n f o article history: received 2 october 2022 received in revised form 20 nov. 2022 accepted 27 november 2022 keywords: deep drawing process coefficient of friction die shoulder radius low carbon steel forming load a b s t r a c t understanding sheet metal forming presses are important to reduce manufacturing costs. thus, the best method of finding the optimum values of processing is by studying the effect of forming parameters on the behavior of formability, friction, and die radius. in this work, the deep drawing process of a low-carbon steel cup was studied and the significance of two important process parameters are investigated which are the friction coefficient and the radius of the die. the finite element method program, ansys, is used to study the effect of these parameters on forming load in the deep drawing process. the three levels of friction coefficient are considered which are 0.08, 0.00, and 0.15, and three die shoulder radius of 4, 6, and 8 mm. the results show that the predicted behavior of the punch load coincided well with both experimental and practical behaviors and the confidence is exceeding 94%. the wrinkling defect is happening when using a high die radius, rd=8mm although the punch load is low due to the increase in the surface area on the edge of die. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction one of the most important manufacturing processes is the sheet metal forming which is considered is a cheap process when using in the mass production in industries application [1]. deep drawing is used to manufacture a cylindrical cup with constant thickness distribution[2]. the initial shape of deep drawing blank is a flat circular blank which is set to form the cylindrical cup. forming load was applied on blank by using punch and die to form the desired shape without folding the corners. a double action for punch force and blank holding force was applied at the same time on the blank to achieve the forming part. deep drawing can also be defined as the combined of compression and tensile deformation of a sheet to form a hollow body at the constant sheet thickness [3]. below are details about the most importance parameters that effect of forming load in deep drawing process. 1.2 the effect of friction the most important variable in drawing process is the friction. the forming force, blank holder type, and blank holder force are depended on the friction value. the hollow bodies that are produced as a result of applying deep drawing process on metal blanks using die, punch, and blank holder, have http://qu.edu.iq/ mailto:abdullah.f.huayier@uotechnology.edu.iq https://doi.org/10.30772/qjes.v15i4.854 https://doi.org/10.30772/qjes.v15i4.854 http://creativecommons.org/licenses/by/4.0/ khalida mansor /al-qadisiyah journal for engineering sciences 15 (2022) 218–223 219 an impact the on selection of lubricant. also, the friction type is a complex process in comparison to other processes due to the need f a low friction in sometimes, and also a high friction in other applications [4].importanttance parameters affectffect on friction is the selection of lubrication type as well as friction coefficient. 1.2.1 lubrication effect the galling (pressure welding) between the die-blank and punch blank metal is happened in drawing process due to the sliding contact under pressure [5]. drawing force increases when an extreme galling which occurs and unequal load distribution causes a fracture in the work piece. one of the most factors to prevent the failure such as wrinkling or tearing is the selection of the suitable lubricant during the deep drawing process as well as the ease of use and removal [6]. 1.2.2 friction coefficient when using high value of friction coefficient, the wrinkling defect can be eliminated. however, in this case, the load distribution will be unequal, and consequently, this causes cracks and fracture in the material as shown in fig. 1,.the friction coefficient redound of (6.33%) of the total variance in the height of the drawn cup. the coefficient of friction increases with respect to the increase in the drawing cup height[7]. the risk of its wrinkling is occurred due to the tangential compression stress. this risk is likely occurred if there is a big difference between the initial blank diameter and the final diameter of forming cup and the sheet thickness is small [8].yang, used the finite element method (fem) to simulate the deep drawing process, and studied the strain distribution under different friction coefficients, and then applied the results in an experimental work and conducted a comparison between them [9]. figure 1. influence of the friction coefficient on the material’s damage[8] liu qiqian et. al. (2012) analyzed the process of microdot formation with a pillow using fem that used to study the effect of the forming size and simulate the micro-forming process in multiple-points. the research aimed to study the effect of friction coefficient between materials on the surface finish and distribution of thickness of the final product from the center to the edge in the deformed plates[10]. 2. objective the aim of the work is to show the: 1. study of the effect of friction coefficient on punch load as well as the wrinkling defect. 2. the effect of die radius on forming behavior and formability. 3. theoretical consideration the important variables that affect the quality of the product are punching force (fdr), the radiuses of die and punch (rd, rp), blank holding force (bhf), blank thickness (t), and the ratio of the draw which includes the ratio of the blank diameter to the punch diameter (d/d). in addition, material properties influence the product quality and cost in sheet metal forming process. fig. 2 shows the deep drawing process geometric variables. figure 2. schematic the deep drawing process 3.1 the drawing force the work required to draw the blank into a cup is supplied by the punch force. the force exerted by the punch depending on the process parameter. the work required is a combination of pure deformation work and frictional work. the deformation work also depends on the fact that the forming mechanism is pure stretch forming, pure drawing or combination of both. a great many parameters are involved in determination of deformation work and consequently the punch force. certain simplifying assumptions have to be made in order to determine an expression for maximum punch force [11]. this force can be estimated by following equation: 𝑭𝒅𝒓 = 𝝅 ∗ 𝒅 ∗ 𝒕 ∗ 𝝈𝒖 ∗ (𝜷 − 𝑮) (1) where: fdr= drawing force σu = ultimate tensile stress g = constant (0.6 – 0.7) to cover bending and friction it was observed that by varying the metal volume and metal resistance, the punch force will be increased and reaches to the maximum value, and after that top point, it been gradually decreases to zero. the maximum value of drawing force occurred when the punch depth is equal to (rp+rd), or at value around (0.333) of the punch stroke length [12]. 3.2 the influence of friction 220 khalida mansor /al-qadisiyah journal for engineering sciences 15 (2022) 218–223 when the friction between blank and punch increases, it can be seen that the material flows from underneath the punch bottom over the punch nose. the high friction coefficient will prevent the flow of material over the punch nose, which in turn will prevent excessive stretching of the sheet metal at the bottom of the punch, and consequently increases the limit drawing ratio (ldr). the high friction coefficient between die and sheet will decrease the ldr. existing the friction over the die corner radius and in the flange, causes a difficulty in drawing of the sheet metal. it will increase the required punch force. this situation will cause excessive stretching and a fracture in the unsupported regions. fig. 3 shows the coefficient of friction increases when the limiting drawing ratio (ldr) was decreases [13]. figure 3. relation between friction coefficient and ldr [13] the friction resistance stresses (𝜏ƒ) for flat surface is a result of multiplying of the friction coefficient (μ), and the blank holder pressure (p), as illustrated by the following equation: τf = μ ∗ p …(2) and, for the inclined surface has an angle (α): τf = μ ∗ p ∗ cos⁡(α) …(3) 3.3 the influence of die profile radius: die radius (rd) depends on the workpiece size and thickness, and large radius of die is required to use in order to increase the limit drawing ratio and also to reduce the drawing load. however, there is a decrease in the contact area between the empty holders at using of large die radius. additionally, there is an increase in the probability of occurrence of the wrinkles [14]. 4. numerical simulation fem was used to analyze the forming process under the specified working conditions that entered by the users. the users are changing and repeating the conditions and conducting the analysis until they find the suitable conditions that reduce the efforts of the users in numerical simulation, which used to: • predicting the material flow during the particular process (on the draw beads in deep drawing). • predicting the punch force, blank holder force and the stresses that are necessary to execute the forming process. • prevent the failure which could be caused by the defect in diepunch design. in this work the commercial finite element package (ansys 14) is used to simulate the process of draw bead in deep drawing process for cup forming. the numerical results have compared with the experimental results. the punch, die and the blank holder represented by (target 169), which defined by three nodes, and each node has two degrees of freedom. the blank material represented by (visco 106), which defined by four nodes, and each node has up to three degrees of freedom. the contact interface between die and the deformed material is represented by (contact 171), which has two degrees of freedom at each node. the loading was conducted in the form of a prescribed displacement. the isotropic hardening plasticity model have been used. as the driving force to obtain plastic response, the von mises stress has been applied to compute by the most commercial fem package as illustrated in fig .4. figure 4. simulation of present work using ansys (14) program the result of deep drawing analysis was illustrated in table 1. with different coefficient of friction and their effect on punch load variations when the die radius is 4. and after that, a numerical simulation was performed to investigate the effect of die radius on deep drawing process. different simulations with two die radius; 6 & 8, and at different coefficient of friction; 0.08, 0.1, and 0.15 were performed. table 1. illustrated the result using finite element at different coefficient of friction (rd=4mm) µ=0.15 without lubrication µ=0.1 using wax µ =0.08 with graphite and grease punch stroke punch load punch stroke punch load punch stroke punch load 0 0 0 0 0 0 0.9854 1.235 1.0752 1.165 1.0102 0.9025 3.0124 5.364 2.2542 5.231 2.9956 3.365 5.9854 10.089 6.3674 9.9806 6.1202 7.5326 9.1235 20.147 9.3275 18.0123 9.2235 15.6541 11.9852 22.457 13.533 20.4561 13.0125 18.9541 khalida mansor /al-qadisiyah journal for engineering sciences 15 (2022) 218–223 221 14.9582 26.4971 15.5451 23.2564 15.212 23.4587 16.3652 28.9522 18.1106 26.4589 18.125 25.6871 18.5682 31.512 20.1204 30.2101 19.2669 28.3654 19.6985 32.3425 22.9841 31.123 20.2365 29.5841 22.8562 32.0143 24.721 30.952 23.256 25.3641 24.2658 30.478 26.0985 29.7841 25.2365 21.0124 25.9856 27.1438 26.2854 25.142 26.321 19.2541 28.0125 18.42 28.1235 17.5421 28.0112 15.2364 28.9985 15.0954 29.1024 14.4536 29.1145 11.131 31.3254 12.3246 31.5012 11.4581 31.3956 9.5471 5. experimental work after applied the finite element analysis with appropriate forming condition and used this result in experimental work. the experimental work conducted using instron universal testing machine which has a force capacity 180 kn and speed of the testing was kept constant at 10 mm/min. the forming blank has 80 mm a diameter, 0.5 mm thickness, and made from low carbon steel (1006–aisi) of the following mechanical composition is listed in table 2. a typical cylindrical cup drawing process was chosen for detailed analysis in deep drawing process with draw beads that presented in fig. 5. the cup (40 mm) outer diameter with die profile radius (rd=4, 6 and 8) and punch diameter (38.8mm) with corner radius (rp=2mm) was used to completely drawn the die that shown in fig 6. table 2. low carbon steel mechanical properties (1006–aisi) property value young modulus (gpa) 200 position ratio 0.3 yield stress (mpa) 125 tangent modulus (gpa) 0.52 the experimental result of deep drawing process was illustrated in table 3. with different coefficient of friction and their effects on the punch load variations when using die radius (rd=4). following, the experimental work was conducted with die radius (rd=6) and die radius (rd=8) and the coefficient of friction varies from a low of 0.05 to 0.2. figure 5. experimental setting of deep drawing process figure 6. samples of completely drawn cup table 3. illustrated the result of experimental work at the different coefficient of friction (rd=4mm) µ=0.15 without lubrication µ=0.1 using wax µ =0.08 with graphite and grease punch stroke punch load punch stroke punch load punch stroke punch load 0 0 0 0 0 0 1.121 1.14 0.998 1.012 1.002 0.958 2.312 3.985 2.341 3.457 2.262 3.12 6.21 7.214 6.187 7.101 6.214 7.011 9.241 11.561 9.365 10.452 9.353 10.124 13.501 13.985 12.785 12.875 12.675 12.231 15.212 17.567 15.321 16.245 14.985 15.998 18.21 19.587 18.01 17.895 18.142 17.745 20.31 21.542 19.998 20.154 19.874 19.895 22.695 25.654 22.11 24.652 22.562 23.997 24.575 29.584 24.352 28.245 24.152 27.254 26.213 31.524 26.114 29.587 26.241 28.114 26.562 33.254 26.568 31.251 26.415 29.245 28.141 30.241 28.21 29.584 28.325 28.114 29.256 24.251 29.14 23.154 29.354 21.457 31.378 18.354 31.375 16.254 31.241 14.654 6. results and discussions variation of the friction coefficient, the die radius in nine different cylinder shapes (3x3) is considered to study their effect on the forming process behavior, in particular the punch load. fig. 7 illustrated the relationship between the punch load and the punch stroke in simulation and experimental works. while, fig. 8 presents the confidence between the punch load in numerical and experimentally at different values of coefficient of friction. it has seen from the figure for µ=0.15 (without lubrication), the required forming load is 33.254 kn. while for experiment under coefficient of friction 0.08, radius equal to 6 mm, and the lubricant is grease, the forming force is down to 28.998 kn and there is no difference in the simulation and experimental results under the same conditions of coefficients of friction. wrinkling defect occurs when the applied punch load is at lower level and coefficients of friction 0.08 accompanying with using graphite and grease as a lubricant. 222 khalida mansor /al-qadisiyah journal for engineering sciences 15 (2022) 218–223 figure 7. the relation between punch stroke and punch load, (a) simulation, (b) experimental figure 8. confidence between fem and exp. with different parameters. 7. conclusions 1. finite element method was used to simulate the forming process of a cylindrical shape and the result has been compared to experimental work with different values of parameters (coefficient of friction and die radius). 2. from the results shown in figures (7), the predicted behavior of forming process was clearly indicated that the punch load with coincided well with a a a b b b 92 94 96 98 100 0.150.10.08 c o n fi d e n ce % coefficient of friction r=6mm r=4mm r=8mm khalida mansor /al-qadisiyah journal for engineering sciences 15 (2022) 218–223 223 both analytical and experimental behaviors and the overall deviation are not exceeding 6%. 3. the effect of two die geometry parameters: die radius and coefficient of friction, on the load forming distribution were studied by simulation and experimental work. the results showed when the coefficient of friction increases and die radius decreases, the forming force will be increased. 4. from the results, they show that using high die radius (rd=8) with applying low force punch, is a main reason for occurring of wrinkling defect. references [1] tahir altinbalik, aysun tonka, numerical and expermintal study of sheet thickness variation in deep drawing processes, international journal of modern manufacturing technologies issn 2067–3604, vol. iv, no. 2 / 2012 [2] a.d.younis, the effect of drawing ratio in deep drawing process on thickness distribution along the cup, al-rafidain engineering vol.18 no.4 august 2010 [3] d.swapna, ch.srinivasa rao, s.radhika, b.raviraja, deep drawing process: a brief overview, ncamms 2015 [4] ter verkrijging van: “modelling of contact and friction in deep drawing processes”; printed by febo druk b.v., enschede; printed by febo druk b.v., enschede [5] nayan kaneriya, darshan shah, rishit rana, vaishal shah, parth thakkar, effect of different parameters on deep drawing process for minimum stress and defects by experimental and simulation study: a review, international journal of advance engineering and research development volume 3, issue 10, october -2016 [6] a. r. joshi, k. d. kothari, dr. r. l. jhala, effects of different parameters on deep drawing process: review, international journal of engineering research & technology (ijert) vol. 2 issue 3, march – 2013 [7] a. chennakesava reddy “parametric significance of warm drawing process for 2024t4 aluminum alloy through fea”, international journal of science and research, vol. 4, no. 4, pp. 2345-2351, 2015. [8] devendar.g, a. chennakesava reddy, study on deep drawing process parameters a review, international journal of scientific & engineering research, volume 7, issue 6, june-2016 issn 2229-5518 [9] t.s. yang “investigation of the strain distribution with lubrication during the deep drawing process”, tribology international, vol. 43, pp 1104– 1112, 2010. [10] liu qiqian, lu cheng, fu wenzhi, tieu kiet, li mingzhe, gong xuepeng “optimization of cushion conditions in micro multi-point sheet forming” [11] vukota boljanovic "sheet metal forming processes and die design" isbn 0-83 1 1-3 182-9 (2004). [12] kakandikar g.m. "optimization of forming load and variables in deep drawing process for automotive cup using genetic algorithm " prentice hall of india private limited, new delhi, pp 1-4, (2008) [13] j. a. schey, “introduction to manufacturing process”, third edition, mc graw-hill series in mechanical engineering an material science, isbn 0070311, (2000). [14] d. e. ostergaard “advanced die making”, mcgraw-hill book company,(1967). [15] jalil jabbar shukur, effect of blank holder types on drawing of mild steel round cup with flange, university of technology,2013 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� shear buckling behavior of rectangular thin plate with variable thickness dr. husain m. husain professor in civil engineering, university of tekrit dr. haider k. ammash lecturer. in civil engineering, university of al-qadisyia abstract a simplified computational procedure for shear buckling problems of rectangular thin plates with constant and variable thickness is presented. the discretization of the problem is carried out by means of finite differences. geometric and material non-linearity are neglected. the effect of boundary conditions, aspect ratios, and tapering ratios on the shear buckling behavior is considered. the plate was analyzed with different tapering ratios (ta/to) (1.0, 1.25, 1.5, 1.75, and 2.0). it is concluded that the shear buckling behavior of thin plate is very sensitive to the magnitude of tapering ratio. keyword: finite differences, eigen-value problem, buckling behavior, rectangular plates, tapered plates ��� �� ا�����ي ا���نةا�� �� ا�زا����� �� ��� �ا��)ن ��'&!%$ #�� "��! �� ا���اص �� ��)ر آ!.,�!ش.د �5ا�34)�2 ا��)��1 آ��� ا�34)�2-8!"�7 ا�6!د��2 ���9 "��) ���9. د.ا �5ا�34)�2 ا��)��1 � آ��� ا��7"!8-�2(34 ���: ��>;�ا ������ �� ��� ��� /�0 /����. ا����-�� . ������+ ا*(�)� ج ا����ن ��%$ #" ر ���� �������� ذات ُ���� ُ������ ا������ ��م ا����� �� �����4ام �� ���� ا�$�و �� ت ا������دة . ��5� /��0 /�?���+ ���<=�ات ا9���8ف ا���ُ��� و(���; ا: )�� د .ا������89 ا��75����� وا�� د ��� /��0 اه� 7 د a�@ ��+ ا*(�) ج �bوف ا�cوd%�+ ا�%$��. ا���٢.٠و ،١.٠,١.٢٥,١.٥,١.٧٥(� �� (��; ا9��8ف ا����� /0 /� .( n���/َ #" ا�� ��� �� س �rا ا�@ ��� ا����� dq ا9�8ف ا�����n ذ�� أن ��+ ا*(�) ج$%�� d%�ا� . al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� notations a 2244 866 yxyx hhhh ++= =b,a plate dimension in x and ydirections respectively. [b] = in-plane stiffness matrix. )( 222 4 yxyx hhhb ++++−−−−==== )( 222 4 yxxy hhhb ++++−−−−==== 22 2 yx hhc ==== c = clamped edge. ( ) ooat atttc −= =slope coefficient inthe plate. (((( ))))23 112 vetd o −−−−==== modulus of rigidity. (((( ))))23 112 vetd avav −−−−==== 4 yx hd ==== 4 xy hd ==== ====e modulus of elasticity. ====yx hh , mesh size at x and y-direction, respectively. [k] = bending stiffness matrix. nx, ny, nxy = in-plane forces. q= transverse load. s = simple supported edge. t = plate thickness. ta = thickness at the side x=a. tav = average thickness ((ta+to)/2). to = thickness at the side x=0. ====νννν poisson’s ratio. w = out-of-plane displacement. introduction thin plate elements used in naval and aeronautical structures are often subjected to normal (figure 1) and shearing forces acting in the plane of the plate. if such in-plane forces are sufficiently small, the equilibrium is stable and the resulting deformations are characterized by the absence of the lateral displacements. as the magnitude of these in-plane forces increases, at certain load intensity, a marked change in the character of the deformation pattern takes place. that is, simultaneously with the in-plane deformations, lateral displacements are introduced. in this condition, the originally stable equilibrium becomes unstable and the plate is said to have buckled. the load producing this condition is called the critical load. the importance of the critical load is the initiation of a deflection pattern, which, if the load is further increased rapidly leads to very large deflections and eventually to complete failure of the plate. this is a dangerous condition, which must be avoided. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� though considerable amount of information is available on the buckling of isotropic and orthotropic plates of constant thickness with different boundary conditions and subjected to various types of loading [ e.g. salvadori (1949), timoshenko and gere (1961)], there are limited number of research works on rectangular plates with variable thickness. chehil and dua (1973) investigated the buckling behavior of simply supported rectangular plates with a linear thickness variation in one direction. they employed perturbation method to solve the governing equation of rectangular plate with variable thickness. kobayashi and sonoda (1990) used a power series method with the used of a coordinate transformation to solve analytically the buckling problem of uniaxially compressed rectangular plates with linearly tapered thickness. chin, et al (1993) used finite element method to predict the buckling capacity of arbitrary shaped thin-walled members under any general load and boundary conditions. ohga, et al (1995) used analytical procedure for the elastic buckling problems of thin-walled members with variable thickness cross section by using the transfer matrix method. more recently, hussain, et al (2002) used the finite difference method to estimate buckling factor of rectangular plate with variable thickness cross section. the present paper is concerned with the elastic buckling behavior of rectangular thin plate with variable thickness under shear load with types of boundary conditions. in this study, a simplified finite difference method used to solve the governing differential equation of plates with variable thickness. the influences of thickness variation, plate aspect ratios, and boundary conditions on the buckling load are examined. governing equation and solution the buckling of isotropic rectangular plates with linearly tapered thickness in the x-direction is considered as shown in figure 2. the plate is subjected to uniform compressive load in y-direction. the thickness )( xt and moment of inertia )( xi are expressed as: )()( xctxt to ++++==== 1 (1) 3 1 )()( xcixi to ++++==== (2) in which ooat atttc )( −−−−==== ; o t and a t denote the thickness at the sides 0====x and ax ==== , respectively; 12 3 oo ti ==== is the second moment of area(per unit width) for the plate cross section at the side 0====x . within the classical small deflection theory of thin plates, the differential equation for the rectangular plate under consideration can be written in the form [hussain, et al (2002)]: (((( ))))         ∂∂∂∂∂∂∂∂ ∂∂∂∂ ====         ∂∂∂∂ ∂∂∂∂ ++++ ∂∂∂∂ ∂∂∂∂′′′′′′′′ ++++         ∂∂∂∂∂∂∂∂ ∂∂∂∂ ++++ ∂∂∂∂ ∂∂∂∂′′′′ ++++∇∇∇∇ yx w n dy w x w i i yx w x w i i w xy xx x x x 2 2 2 2 2 2 3 3 3 4 12 νννν (3) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� in which (((( )))) (((( )))) (((( ))))23 112 vetd xx −−−−==== = is the flexural (or bending) rigidity of the section of the plate (and this is varying with respect to x). 4 4 22 4 4 4 4 2 yyxx ∂∂∂∂ ∂∂∂∂ ++++ ∂∂∂∂∂∂∂∂ ∂∂∂∂ ++++ ∂∂∂∂ ∂∂∂∂ ====∇∇∇∇ )( )( )( xcici xcici xcii totx totx tox ++++====′′′′′′′′ ++++====′′′′ ++++==== 16 13 1 2 2 3 the solution of equation (3) may be achieved by finite difference method as shown in figure 3. by applying the finite difference molecules at the interior nodes of the subdivided plate, the following system of simultaneous linear equations in matrices will be obtained: [[[[ ]]]]{{{{ }}}} [[[[ ]]]]{{{{ }}}} 0====++++ wbwk λλλλ (4) where the matrices [[[[ ]]]]k and [[[[ ]]]]b may be named as follows: [[[[ ]]]]k : is the stiffness matrix for the plate [[[[ ]]]]b : is the geometry matrix for the plate notice that equation (4) is an eigen-value problem. for a given thickness (((( ))))ao tt , and plate– aspect ratio ba , the eigen-value ( λλλλ ) can be determined numerically by using any relevant technique. the smallest eigen-value gives the most (fundamental) buckling load. numerical results since accuracy of the buckling load depends on the mesh size and on the order finite difference approximation. the mesh effect has been investigated for a square plate. table (1) gives a measure of convergence as a function of mesh size. it can be seen that a (16 × 16) mesh for this problem that gives results to within (2%) of the exact results (9.350) () . comparison with other theoretical studies figure (4) shows a comparison of the buckling coefficient, which are obtained by the finite difference method and theoretical results by [timoshenko and gere (1961)] for two boundary conditions of all simply supported edges and all clamped edges. good agreement with theoretical results is achieved for every boundary condition. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� parametric study the effects of boundary condition and tapering ratio on the buckling behavior under shear load are studied. figures (5-10) present the relation between buckling coefficient ( avyxxysh dhhnk 22 2==== ) and aspect ratio (a/b) of a rectangular thin plate with different boundary conditions and different tapering ratios. the plate is analyzed with different tapering ratios (ta/to) (1.0, 1.25, 1.5, 1.75, and 2.0). the aspect ratio (a/b) is taken to be in range (0.5 and 3.0). the boundary conditions are taken to be as [ all simply supported edges (ssss), three edges simply supported and other edge clamped (sssc), two edges simply supported and other clamped edges (sscc), three edges clamped and other edge simply supported (sccc), all edges clamped (cccc), and two edges simply supported and other edges clamped (scsc)] . from these figures, it can be seen that: 1. the buckling coefficients decrease when the aspect ratio increases. 2. the buckling coefficients decrease when the tapering ratio increases (for the same volume of the plate). 3. the decreasing in the buckling coefficients when the aspect ratio (a/b) <1.0 less than the decreasing in the buckling coefficients when the aspect ratio (a/b) >1.0. 4. the decreasing in the buckling coefficients in plate with boundary condition (sscc) more than the decreasing in the buckling coefficient in plate with boundary condition (scsc). conclusions a finite difference method has been employed to solve numerically the buckling problem of rectangular plates with linearly tapered thickness under shear load. the effect of plate aspect ratio, boundary condition, and tapering ratio on the buckling behavior are considered. the values of buckling coefficients decrease with an increase in the tapering ratio (for the same volume of the plate). references 1. chajes, a., “principles of structural stability theory”, printicehall, inc., englewood cliffs, new jersey, 1974. 2. chehil, d.s., and dua, s.s., “buckling of rectangular plates with general variation in thickness “, j. appl. mech., vol.40, 1973, pp.745-751. 3. chin, c. k., al-bermani, f. g. a., and kitipornchai, s., “finite element method for buckling analysis of plates structure”, asce, j. struct. eng, vol.119, no.4, apr., 1993, pp.1050-1068. 4. fok, w.c., “evaluation of experimental data of plate buckling”, asce, j. eng. mech., vol.110, no.4, 1984, pp.577-588. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 5. gallagher, r.h., “finite element analysis fundamentals”, prentice-hall, inc., englewood cliffs, new jersey, 1973. 6. gaylord, e.h., and gaylord, c.n., “design of steel structures”, mcgrawhill kogakuasha, ltd., 1972. 7. hussein, h.m., al-daami, h., and amash, h.k., “buckling behavior of rectangular plate with variable thickness.” eng. of technology vol.21, no.10, 2002, pp.736-745. 8. jaeger, l.g., “elementary theory of elastic plates”, pergamon press ltd. headington hill hall, oxford, 1964. 9. jia-rang, f., “plates of varying thickness with four simply supported edges”, asce, j. eng. mech. div., vol.108, no. em1, feb., 1982, pp.167-179. 10. kopayashi, h., and sonoda, k., “buckling of rectangular plates with tapered thickness”, asce, j. struct. eng., vol.116, no.5, may, 1990, pp.1278-1289. 11. mirambell, e., zarate, a.v., “web buckling of tapered plate girders”, proc. inst. civ. eng. structs & bldgs, vol.140, feb., 2000, pp.51-60. 12. mohammed, a.m., “effect of initially imperfect and boundary condition on the buckling and post-buckling behavior of steel plates”, m.sc. thesis, department of building and construction, university of technology, iraq, 2001. 13. murray, n.w., “introduction to theory of thin walled structures”, oxford univ., press, new york, 1986. 14. ohga, m., shigematsu, t., and kawagouchi, k., “buckling analysis of thin-walled members with variable thickness”, asce, j. struct. eng., vol.121, no.6, june, 1995, pp.919-924. 15. salvadori, m.g., “numerical computation of buckling loads by finite differences”, asce, trans., dec., 1949, pp.590-636. 16. saxena, h.c., “the calculus of finite differences”, s. chand & company, ltd, 1980. 17. shanley, f.r., “mechanics of materials”, mcgraw-hill kogakuasha, 1967. 18. stein, m., “behavior of buckling rectangular plates”, asce, j. eng. mech. div., vol.86, no.em2, apr., 1960, pp.59-76. 19. szilard, r., “theory and analysis of plates: classical and numerical methods”, prenticehall, inc., englewood cliffs, new york, 1974. 20. timoshenko, s.p., and woinowshy, s., “theory of plates and shells”, 2nd ed, mcgraw-hill book co., inc., new york, 1959. 21. timoshenko, s.p., and gere, j.m., “theory of elastic stability”, 2nd ed, mc graw-hill book co., inc., new york, 1961. 22. ugral, a.c., “stresses in plates and shells”, mcgraw-hill, inc, 1981. 23. wang, p.c., “numerical matrix method in structural mechanics”, john wiley & sons, inc., new york, london, sydney, 1966. 24. williams, d.g., and aalami, b., “thin plate design for in-plane loading”, halsted press, a division of john wiley & son, inc., new york, 1979. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� mesh size shear buckling coefficient 8 × 8 10.137 10 × 10 9.824 12 × 12 9.661 14 × 14 9.570 16 × 16 9.511 18 × 18 9.470 20 × 20 9.440 nx nx ny ny τxy τxy x y b a figure (1): plate under a general pattern of combined external loads figure (2): rectangular thin plate with variable thickness under axial shear load (a) plate under axial load. (b) plate cross section. b a nxy x y a ta to x table (1): convergence of buckling coefficient ( sh k ) for a square simply supported with constant thickness (a/b=1.0) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� 4 xy hd 24 yxy hzhb νννν+ 23 yx hfhc − 23 yx hfhc + )hh( hzha xy yx 22 22 2 νννν+ − 42 234 )(2 yx yxyxx hzh hhhhfb + ++ 42 234 )(2 yx yxyxx hzh hhhhfb + +− 4 yxx hfhd + 4 yxx hfhd − 24 yxy hzhb νννν+ 23 yx hfhc − 23 yx hfhc + 4 xy hd figure (3): plate equation in finite difference molecule form figure (4): comparison of buckling coefficient ( sh k ) of rectangular thin plate with constant thickness 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 35 40 45 b u c k li n g c o e ff ic ie n t present study ref [1] all edges clamped all edges simply supported ref [21] al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 b u c k li n g c o e ff ic ie n t s s s s figure (5): comparison of buckling coefficient ( sh k ) of rectangular thin plate with all edges simply supported 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 b u c k li n g c o e ff ic ie n t ta/to 1.0 1.25 1.5 1.75 2.0 s s c s figure (6): comparison of buckling coefficient ( sh k ) of rectangular thin plate with three edges simply supported and other edge clamped al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 35 b u c k li n g c o e ff ic ie n t ta/to 1.0 1.25 1.5 1.75 2.0 s c c s figure (7): comparison of buckling coefficient ( sh k ) of rectangular thin plate with two edges simply supported and other edges clamped 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 35 40 45 b u c k li n g c o e ff ic ie n t ta/to 1.0 1.25 1.5 1.75 2.0 a/b s c c c figure (8): comparison of buckling coefficient ( sh k ) of rectangular thin plate with three edges clamped and other edge simply supported al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 35 40 45 b u c k li n g c o e ff ic ie n t ta/to 1.0 1.25 1.5 1.75 2.0 c c c c figure (9): comparison of buckling coefficient ( sh k ) of rectangular thin plate with all edges clamped 0.0 0.5 1.0 1.5 2.0 2.5 3.0 aspect ratio ( ) 0 5 10 15 20 25 30 35 40 45 50 b u c k li n g c o e ff ic ie n t ta/to 1.0 1.25 1.5 1.75 2.0 s s c c figure (10): comparison of buckling coefficient ( sh k ) of rectangular thin plate with two edges simply supported and other edges clamped article al-qadisiyah journalfor engineering sciences15 (2022) 136–141 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: eng.chem.20.post.6@qu.edu.iq (zahraa m.gafil) https://doi.org/10.30772/qjes.v15i2.825 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. treatment of hospital wastewater by potassium ferrate zahraa m. gafil *, husham m. al.tameemi, and ahmed abbas obaid department of chemical engineering, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 05 may 2022 received in revised form 01 june 2022 accepted 13 july 2022 keywords: oxidation hospital wastewater treatment potassium ferrate response surface methodology a b s t r a c t it has been investigated how well potassium ferrate (k2feo4) treats hospital wastewater effluents. in the treatment of water and wastewater, potassium ferrate serves as an oxidant, disinfectant, and coagulant with several functions. the effects of combining the oxidation and coagulation processes on features have not been extensively studied. the objective of this study is to evaluate the oxidation and coagulation effects of potassium ferrate treatment methods. an optimization technique based on response surface methodology (rsm) and box-behnken design(bbd) was utilized to identify the ideal conditions for increased removal efficiency of chemical oxygen demand (cod). potassium ferrate has a significant impact, according to experiments. with a cod of 790 ppm as the starting point, the effects of oxidation time (30-90 minutes), potassium ferrate concentration (20-100 ppm), ph (3-9), and process stirring speed (100-400 rpm) on cod removal efficiency were examined. to find the best cod removal efficiency, it also used an optimization strategy based on the box-behnken design via the response surface method (rsm). according to the findings, time, mixing speed, and ph are the factors that have the highest impact on the effectiveness of cod removal. based on the study of the minitab-19 program, regression analysis results revealed a fisher value of 13.68. ph value 3, oxidation time of 62 minutes, mixing speed of 300 rpm, and potassium ferrate content of 92 ppm was discovered to be the optimal operating parameters. based on this ideal scenario, the final concentration reached had a cod elimination effectiveness of 98 percent. ©2022university of al-qadisiyah. all rights reserved. 1. introduction recent years have seen an increase in the study of how prescription medications affect the aquatic environment as a result of industry, medical facility, and household wastewater discharges [1-3]. long-term effects on individuals and ecosystems are difficult to predict due to a lack of understanding of the sustainable effects of exposure to very low concentrations , bioaccumulation, teamwork, or the aggregate of several molecules. however, it is still challenging for international water companies to find ways to dispose of them. contaminants because of concerns about their potential for negative effects. utilizing activated sludge and subsequent sedimentation, approximately 80 % of the total pharmaceutical load pass through the treatment vegetation[4]. many physical, organic, and chemical strategies were explored and reviewed [5] because the conventional wastewater remediation method isn't always effective in getting rid of prescription medicines. iron-based material ferrate (vi) (feo42), one of the many oxidants used in the wastewater http://qu.edu.iq/ mailto:eng.chem.20.post.6@qu.edu.iq https://doi.org/10.30772/qjes.v15i2.825 http://creativecommons.org/licenses/by/4.0/ zahraa gafil et al /al-qadisiyah journal for engineering sciences 15 (2022) 136–141 137 treatment industry, has proven to be effective at removing a great variety of prescription medications, including antibiotics, lipid regulators, antipyretics, anticonvulsants and betabloquants [6,7].with redox capability, ranging from 0.72 v in alkaline media (ph = 14) to 2.20 v below barely acidic conditions (ph = 0), fe(vi) well-known exhibits several advantages. it acts primarily as an oxidizer and disinfectant for the entire ph range. it is subsequently converted to the coagulant ferric hydroxide, fe(oh)3, which is non-poisonous. nine due to its ability to oxidize, disinfect, coagulate, and precipitate pollutants both naturally occurring and inorganically[9–11], fe(vi) appears to be effective. fe(vi) has many benefits compared to other commonly used oxidizers such as chlorine, chlorine dioxide, permanganate, hydrogen peroxide, and ozone., including its versatility and environmental friendliness[12]. the use of potassium ferrate(vi) as a chemical reagent for wastewater treatment has been extensively reviewed by a number of authors.the use of ferrate(vi) to oxidize a variety of synthetic organic molecules, including alcohol [14] and carboxylic compounds [15]. iron (vi) compounds may be utilized as inhibitory additives since the degree of corrosion prevention reached 60%[18]. it can be used as a multifunctional chemical for the treatment of water and wastewater and is a substantial substitute for advanced oxidation techniques (aop)[19]. 2. materials and method 2.1. the chemical oxygen demand (cod) the measurement of organic strength in domestic and commercial waste waters has been thoroughly defined with relation to cod. it is based on the fact that the majority of organic molecules can be oxidized by potent oxidizing agents in acidic conditions. the quick turnaround time is the primary benefit of cod measurements. instead of the five days required by bod, tests might be finished in three hours. therefore, cod may be utilized rather than the bod test [16]. the amount of cod was determined using a sample (2 ml) from the effluent digested with potassium dichromate conducted at room temperature. the following formula was used to compute the cod removal efficiency (r percent) using cod (eq. 1) (k2cr2o7) for 120 minutes at 150 c in a cod thermoreactor. average values were used to analyze the data as: r%= (c0-c) / c0*100 (1) where c0 is the initial concentration of the cod removal and c is the final concentration of the cod removal. 2.2. turbidity measurements after each run, pipet the sample from the beakers into the tube, making sure there are no air bubbles in the hww sample. take into account reading the test sample after it has been placed in a turbid meter that has been calibrated. 2.3 design of experiments to fit the model of any response and identify the ideal operating parameters for this response, a group of statistical and mathematical approaches outlined by minitab-19 software can be employed. the box bhenken design was employed in this work to improve and ascertain the effect of factors like ph and the addition of potassium ferrate on the effectiveness of cod removal by oxidation.response optimization in minitab-19 software can be done in a variety of methods. in order to confirm and contrast variables that affected cod removal from hww, this study used boxbehnken empirical designs with three tiers and four components. potassium ferrate concenteration (x1), mixing speed (x2), oxidation duration (x3), and ph value (x4) were the process variables, and cod elimination efficiency was the outcome. using the middle or center point (0), -1 (low level), and +1, the scale of process variables was coded (high level). the equation below can be used to resolve box–behnken designs and build the necessary quadratic model with the necessary statistical qualities using the runs needed for a 3-level factorial. n =2k (k-1) + cp (2) where cp is the central point's repeated number and k represents the number of processing parameters. as part of this work, 27 trials were performed to assess the impact of process factors on the removal efficiency of cod. the box–behnken design (bbd) suggested for the current study is illustrated in table 2. based on bbd, the following equation [3] can be used to nomenclature ftir fourier transform-infra red bbd box–behnken design xrd x-ray diffraction cod chemical oxygen demand ci confidence interval x1 potassium ferrate concentration ppm dof degree of freedom x2 mixing speed rpm d desirability function x3 x4 oxidation time (min) ph seq.ss sum of square x1 value tagged for cod adj. ss adjusted sum of square x2 speed coded value adj. ms adjusted mean of square x3 time value coding adj. r2 adjusted coefficient of multiple correlation x4 ph value coding predr2 predicted multiple correlation coefficient ao the intercept code n number of runs ai the superior (linear) significant impact k number of processing parameters aii major second-class impact y represents the dependent variable (re) aij the impact of interaction se standard error of regression s standard error of mean 138 zahraa gafil et al /al-qadisiyah journal for engineering sciences 15 (2022) 136–141 characterize how the interaction terms correspond to the test data. in a second order polynomial model: y= a0+ ∑ai xi+ ∑aii xi2+ ∑aij xi xj (3) the method variables (independent variables) are represented by the coded form of x, where y stands for the variable (re), i and j are the pattern index numbers, a0 is the intercept term, and x1, x2,..., xk are the method variables. first-order (linear) effects are the main effects of ai, while second-order and interaction effects are the main effects of aii and aij, respectively. following the analysis of variance, the parametric sstatistics (r2) were calculated to assess the precision of the model fit. 3. results and discussion 3.1 potassium ferrate characteristics ftir, sem, and xrd were utilized by the researchers to describe potassium ferrate. to determine chemical bonds in molecules, ftir is utilized. when potassium ferrate is in powder form, sem is utilized to capture structural images and micrographs. xrd it is an illustration of the analytical methods employed to validate the crystal structures and crystallinity of potassium ferrate. 3.2 statistical analysis for the purpose of maximizing the assembly of a specific material, statistical techniques like rsm are utilized to optimize operational parameters. the determination of the interaction between process components employs statistical tools rather than conventional techniques. in 27 tests, using a variety of process factors in separate groups, suppression ratios and knowledge of optimization between them were examined to see how they evolved.table 3 shows the removal values for each experiment. anova variance analysis, which is a statistical technique that divides the total variation in a large group of data into distinct portions given certain causes of variation, was employed to evaluate hypotheses regarding the model coefficients[12,13]. the fisher f-test and p-test were used to determine whether an anova is adequate. the high value of f shows that the regression equation accounts for the majority of the variation in the result.. to determine whether f is large enough to indicate statistical significance, the accompanying p-value is used. the chosen model was able to explain 95.10 percent of the variability with a p-value of 0.00[16]. the response surface quadratic model's anova was displayed in table 4. the square sum (seqss), degree of freedom (df), adjusted sum of squares (adj ss), and adjusted mean of square were shown in this table (adj ms). at p equal to 0.00 percent contribution from each parameter, f-value, and p-value, the value of f is equal to 13.68 at p. it demonstrates how important the regression model is. a quadratic model of the removal efficiency of cod (re) was created in terms of encoded units for process variables, and the results of the cod removal efficiency were investigated using the minitab19 program as a pilot. cod re% = 79.80 + 0.1225 x1+ 0.0604 x2+ 0.0892 x30.409 x40.000894 x1 20.000049 x2 2 0.000667 x3 2+ 0.0042 x4 2 + 0.000072 x1x20.000208 x1x3+ 0.00917 x1x4 0.000040 x2x30.00493 x2x4 + 0.00994 x3x4 (4) table 1. process variables and their impact on the elimination of cod process parameters range in box–behnken design coded levels low(-1) middle(0) high (+1) x1initial conc. (ppm) 20 60 100 x2mixing speed (rpm) 100 250 400 x3oxidation time(min) 30 60 90 x4-ph value 3 6 9 table 2 . using the box-behnken experimental design r u n b lo c k s coded value in it ia l c o n c . (p p m ) s p e e d ( r p m ) t im e ( m in ) p h x1 x2 x3 x4 1 1 1 0 0 -1 60 250 90 3 2 1 1 1 0 0 100 100 60 6 3 1 0 1 -1 0 60 400 60 9 4 1 0 0 0 0 60 400 60 3 5 1 -1 0 -1 0 60 100 90 6 6 1 -1 0 0 -1 20 400 60 6 7 1 0 -1 -1 0 60 250 60 6 8 1 0 -1 0 -1 60 250 60 6 9 1 0 1 0 -1 60 250 30 9 10 1 0 0 1 1 60 400 90 6 11 1 -1 1 0 0 60 400 30 6 12 1 1 -1 0 0 60 250 60 6 13 1 0 1 1 0 60 250 30 3 14 1 0 0 0 0 60 100 60 3 15 1 0 0 -1 1 60 100 30 6 16 1 -1 0 0 1 20 250 90 6 17 1 0 1 0 1 20 250 60 9 18 1 -1 -1 0 0 20 100 60 6 19 1 1 0 1 0 100 250 30 6 20 1 0 -1 0 1 100 250 90 6 21 1 1 0 0 1 100 250 60 3 22 1 1 0 -1 0 20 250 30 6 23 1 0 0 0 0 60 100 60 9 24 1 0 0 -1 -1 100 400 60 6 25 1 0 -1 1 0 100 250 60 9 26 1 0 0 1 -1 60 250 90 9 27 1 -1 0 1 0 20 250 60 3 zahraa gafil et al /al-qadisiyah journal for engineering sciences 15 (2022) 136–141 139 equation (4) depicts the interaction of the factors and removal efficiency (squared and linear). according to the laboratory scale, increasing efficiency values increase with increasing positive coefficient values, whereas removal efficiency decreases with increasing negative coefficient values. it was discovered that the amount of cod and ph have a positive correlation with increasing efficiency values. figure 2: response surface (a) and contour plot (b) demonstrating the impact of ph and time on the effectiveness of cod removal 3.3 impact of process factors on the effectiveness of cod removal fig. (1-a, 1-b) shows the relationship between potassium ferrate concentration and removal efficiency for various contact times (40, 60, and 80 minutes) and potassium ferrate concentrations (30, 60, and 90 ppm) at ph 6 at 250 rpm. fig. 1-a displays the response surface plot and figure 1-b displays the associated contour plot. the surface plot clearly shows that a decline in removal efficiency occurs throughout a contact time of 40 minutes as the concentration increases. as the 90-minute contact time approached. the effectiveness of elimination changed. additionally, at a concentration of 90 ppm, the data demonstrate that cod removal effectiveness increases with increasing contact time and potassium ferrate concentration. figures 2a and 2b show the impact of ph on the effectiveness of cod removal at various ph values (4, 6, and 8), at a speed of 250 rpm, and with a concentrated dose of 60 ppm. the response surface plot (2a) demonstrates that the effectiveness of cod removal is currently marginally impacted by increasing ph. the related contour piece (2-b) demonstrates that a very small area has the highest cod elimination efficiency value; its ph value was 9. the study, [16,17] demonstrated this. table 3 experimental outcomes for the cod elimination using the "box–behnken design r u n b lo c k s p o ta ss iu m f e r r a te ( p p m ) s p e e d (r p m ) t im e (m in ) p h re% a c tu a l p r e d ic t 1 1 60 250 90 3 98.00 97.1158 2 1 100 100 60 6 95.00 94.6642 3 1 60 400 60 9 93.00 92.4733 4 1 60 400 60 3 98.88 99.5900 5 1 60 100 90 6 93.00 94.4692 6 1 20 400 60 6 91.00 91.1075 7 1 60 250 60 6 96.58 95.8433 8 1 60 250 60 6 95.95 95.8433 9 1 60 250 30 9 91.00 91.6558 10 1 60 400 90 6 96.83 96.6058 11 1 60 400 30 6 94.55 94.1825 12 1 60 250 60 6 95.00 95.8433 13 1 60 250 30 3 96.58 96.1225 14 1 60 100 60 3 93.00 92.6533 15 1 60 100 30 6 90.00 91.3258 16 1 20 250 90 6 93.00 92.4283 17 1 20 250 60 9 88.00 88.9858 18 1 20 100 60 6 90.00 89.4708 19 1 100 250 30 6 96.00 95.6983 20 1 100 250 90 6 98.00 97.9817 21 1 100 250 60 3 97.60 97.7158 22 1 20 250 30 6 90.00 89.1450 23 1 60 100 60 9 96.00 94.4167 24 1 100 400 60 6 97.72 98.0208 25 1 100 250 60 9 97.00 97.2392 26 1 60 250 90 9 96.00 96.2292 27 1 20 250 60 3 93.00 93.8625 (a) (b) 140 zahraa gafil et al /al-qadisiyah journal for engineering sciences 15 (2022) 136–141 when the speed was between (100, 200, 300, and 400 rpm) at a potassium ferrate concentration of (30, 60, and 90) ppm, forms (3-a, 3-b) show the link between the speed and the concentration of potassium ferrate and its effect on the removal rate. the removal efficiency of cod increases as the focus increases, which is evident from the response surface plot (3a), which shows that it has a substantial impact on cod removal efficiency as speed increases at 400 rpm. the accompanying contour plot (3-b) reveals that the cod removal efficiency's maximum value is located in a narrow region with speeds between 330 and 400 rpm and potassium ferrate concentrations between 97 and 100 ppm (a) (b) figure 1: response surface plot (a) and contour plot (b) illustrating the impact of contact duration and potassium ferrate concentration on the effectiveness of cod removal (a) table 4. variance analysis for cod reduction s o u r c e d f s e q s s a d j m s f -v a lu e p -v a lu e 1-model 14 218.39 6 15.600 13.68 0.000 linear 4 173.363 43.341 38.02 0.000 x1 1 109.929 109.929 96.43 0.000 x2 1 18.700 18.700 16.40 0.002 x3 1 23.241 23.241 20.39 0.001 x4 1 21.494 21.494 18.85 0.001 square 4 16.156 4.039 3.54 0.039 x12 1 8.037 10.906 9.57 0.009 x22 1 5.860 6.424 5.64 0.035 x32 1 2.251 1.920 1.68 0.219 x42 1 0.007 0.007 0.01 0.937 2-way interaction 6 28.877 4.813 4.22 0.016 x1*x2 1 0.740 0.740 0.65 0.436 x1*x3 1 0.250 0.250 0.22 0.648 x1*x4 1 4.840 4.840 4.25 0.062 x2*x3 1 0.130 0.130 0.11 0.742 x2*x4 1 19.714 19.714 17.29 0.001 x3*x4 1 3.204 3.204 2.81 0.119 error 12 13.680 1.140 0000 0000 lack-of-fit 10 12.414 1.241 1.96 0.384 pure error 2 1.265 0.633 0000 0000 total 26 232.075 0000 0000 0000 model summary 1.06 769 94.11% 87.23% 67.96% zahraa gafil et al /al-qadisiyah journal for engineering sciences 15 (2022) 136–141 141 (b) figure 3: response surface plot (a) and contour plot (b) demonstrating the impact of potassium ferrate concentration and speed on the effectiveness of cod removal 3.4 the confirmation and optimization test to find the precise position that maximized the desirability function, numerical optimization of the software is used (df). by changing the weight or importance that may alter the qualities of the aim, the ideal goal was selected. maximum, minimum, target, within range, and none were the five choices for the aim fields for responses. the maximum field with the corresponding 'weight'1.0 was chosen because the goal of the current effort is to achieve higher cod removal efficiency. the lower limit for the removal efficiency was set at 88 percent, and the top limit was set at 100 percent. 4. conclusions it has been proven that employing potassium ferrate as an oxidant material allows for the successful elimination of chemical oxygen demand from a simulated wastewater solution. the rms methodology is efficiently used to enhance process variables and determine the ideal values of these variables for cod removal, leading to higher removal efficiency. according to the results of the rsm analysis, the concentration of potassium ferrate has the biggest impact on how well cod is removed. the perfect circumstances created by the modification were 92 ppm of potassium ferrate, a ph of 3, 400 rpm, and 62 minutes of contact time. acknowledgments the authors are appreciative to the staff and technicians from the chemical engineering department, college of engineering, university of al-qadisiyah. references [1] c. boesinger, n. costarramone and a. castetbon, method for preparing alkali metal ferrates, wo2008065279, 2008. [2] d. j. caldwell, f. mastrocco, l. margiotta-casaluci and b. w. brooks, an integrated approach for prioritizing pharmaceuticals found in the environment for risk assessment, monitoring and advanced research, chemosphere, 2014, 115, 4 – 12. [3] o. cardoso, j.-m. porcher and w. sanchez, factorydischarged pharmaceuticals could be a relevant source of aquatic environment contamination: review of evidence and need for knowledge, chemosphere, 2014, 115, 20–30. [4] b. roig, pharmaceuticals in the environment: current knowledge and need assessment to reduce presence and impact, iwa publishing, 2010. [5] j. wang and s. wang, removal of pharmaceuticals and personal care products (ppcps) from wastewater: a review, j. environ. manage., 2016, 182, 620–640. [6] y. lee and u. von gunten, oxidative transformation of micropollutants during municipal wastewater treatment: comparison of kinetic aspects of selective (chlorine, chlorine dioxide, ferrateijvi), and ozone) and nonselective oxidants (hydroxyl radical), water res., 2010, 44, 555–566. [7] v. k. sharma, oxidative transformations of environmental pharmaceuticals by cl2, clo2, o3, and fe(vi): kinetics assessment, chemosphere, 2008, 73, 1379 – 1386. [8] r. h. wood, the heat, free energy and entropy of the ferrateijvi) ion, j. am. chem. soc., 1958, 80,2038–2041. [9] j.-q. jiang, s. wang and a. panagoulopoulos, the exploration of p otassium ferrateijvi) as a disinfectant/ coagulant in water and wastewater treatment, chemosphere, 2006, 63, 212–219. [10] v. k. sharma, ferrateijvi) and ferrate(v) oxidation of organic compounds: kinetics and mechanism, coord. chem. rev., 2013, 257, 495–510. [11] v. k. sharma, oxidation of inorganic contaminants by ferrates (vi, v, and iv)– kinetics and mechanisms: a review, j. environ. manage., 2011, 92, 1051 –1073. [12] v. k. sharma, r. zboril and r. s. varma, ferrates: greener oxidants with multimodal action in water treatment technologies, acc. chem. res., 2015, 48, 182–191. [13] jiang, j.q., lloyd, b., 2002. progress in the development anduse of ferrate(vi) salt as an oxidant and coagulant for waterand wastewater treatment. water res. 36, 1397–1408 [14] norcross, b.e., lewis, w.c., gai, h., noureldin, n.a., lee,d.g., 1997. the oxidation of secondary alcohols bypotassium tetraoxoferrate (vi). can. j. chem. 75, 129–139 [15] bielski, b.h.j., sharma, v.k., czapski, g., 1994. reactivity of ferrate(v) with carboxylic acids: a pre-mix pulse radiolysis study. radiat. phys. chem. 44, 479– 484. [16] sawyer, c. n., mccarty, p. l. & parkin, g. f. (2003). chemistry for environmental engineering and science. 5. edition. new york. [17] talaiekhozani, a., eskandari, z., bagheri, m. &talaie, m. r. (2016). removal of h2s and cod using uv, ferrate and uv/ferrate from municipal wastewater. journal of human, environment and health promotion, 2(1), 1–8. [18] ivanenko, o., shabliy, t., & nosachova, y. (2020). application of potassium ferrate in water treatment processes. journal of ecological engineering, 21(7), 134–140. [19] klis, s., barbusinski, k., thomas, m., & mochnaska, a. (2020). application of potassium ferrate (vi) in the treatment of selected water and wastewater pollutants – short review. architecture, civil engineering, environment, 13(1), 129–138. table 5. the optimal values for maximum cod re% respo nse goal lower target uppe r weight import ance re% maximu m 88 98.88 100 1 1 response fit se fit 95% ci 95% pi re% 100.57 1.07 (98.23, 102.90) (97.27, 103.86) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٨ behavior of thick spherical vessels under high pressure maase fasel mailak college of engineering, university of qadisiya abstract the aim of this study was to investigate elasto-plastic thermal stresses in a thermoplastic of thick spherical vessels under high pressure the present study deals with spherical shells analysis, the elastic and plastic theory of spherical shell is consider in this search, with a thick sphere subjected to different types of loading such as internal pressure, external pressure and thermal loading have been studies. the tresca yield condition used in this study. when the applied pressure exceeds the minimum pressure required to initiate the yielding at the inner radius, plastic zone starts to be formed. the residual stress components also were calculated using elastic and elasto-plastic solution result ك ا���ا��ت ا������ ا���و�� ��� أ��� ط ا�������� 7� a b *�b آ� � ا���1�9 � :� ا�'�د��� :أ�<=>� �ف -��^ ه��mا ا�s���g آ���ن @��� ي ا���q!cدات أ�� ار���� ���8 =���ر ا�'�و���� ��q�,�+�6 -ا���و���� ا 6�ا����ت اo>'� و���� ��ط ا�ab���و@��� ا �ت �t ��ت ا�'�و�� وا�� و�� �'��7 ��ت أ�6 و��� -�) @�,'+o أ���اع -<�'$�� -�^ ا����4ل آ����abط ا��ا�'+�� وا���abط .أ����+����ا ����gر cا �t#1 تmأ�� ��q�+�! ار�� ��<�ر!+� وا���4ل ا�.ا ���را��-� ا��oab .@�? ا���<�ام �t ��� @ �� �6��b�>'ع ��8 ه�m\ ا��#� �وز ا��� ا �� o',��ن ا��#x @67* -#(�� ا���7\ ا�' v�#� 8'ا���ء ا�<�bع �t� 8| ا��( ا�g� ('�ب��ا oab'� &د��. ?�@ y�mآ درا�� ا�q!cدات ا��<oو�� أو ا����g+� و@2n+ ه� �'& ا���7\ ا�'�ن وا�� ن nomenclature σy: yield strength of material of uniaxial tension test σr: radial stress σθ: hoop stress a and b: constant r : radius of thick sphere a: inner radius b: outer radius pe :pressure at plastic zone cr )(σ : the radial stress at r=c c: radius of sphere at plastic zone pi: inner radius po: outer radius tb and ta: temperatures at the outer and inner radius respectively α : linear coefficient of expansion. β: dimensionless quantity al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٦٩ introduction cylindrical or spherical pressure vessels (e.g., hydraulic cylinders, sewage treatment plants, gun barrels, pipes, boilers and tanks) are commonly used in industry to carry both liquid and gases under pressure. when the pressure vessel is exposed to this pressure, the material comprising the vessel is subjected to pressure loading, and hence stresses, from all directions. the normal stresses resulting from this pressure are functions of the radius of the element under consideration; the shape of the pressure vessel (i.e., open ended cylinder, closed end cylinder, or sphere) as well as the applied pressure. a detailed study of stress analysis of spherical pressure vessel with internal pressure and external pressure are to be considered. spherical pressure vessels are classified into thick sphere if the outer radius is larger then the inner radius by 10 %, otherwise the sphere can be considered as thin sphere. in the thin spheres the radial and tangential stresses are assumed to be constant along the thickness of the sphere but in thick spheres the radial and tangential stresses very across the thickness of the sphere according to the type of loading such as internal pressure and external pressure . an effective numerical iterative method is proposed for the pressure loading analysis. elastic stress behavior is considered first, followed by some cases of elasto-plastic stress distributions, and finally plastic deformation. for the spherical pressure vessel, the hoop and axial stresses are equal and are one half of the hoop stress in the cylindrical pressure vessel as shown in figure (1). this makes the spherical pressure vessel a more “efficient” pressure vessel geometry [14] failure criteria the purpose of failure criteria is to predict or estimate the failure/yield of structural members subjected biaxial or triaxial states of stress. there are more one theory for failure criteria, dependent on the nature of the material (i.e. brittle or ductile), as shown below: maximum shear stress criterion, von mises criterion for ductile material. maximum shear stress criterion, tresca's criterion for ductile material. maximum normal stress criterion, mohr’s theory for brittle material. whether a material is brittle or ductile could be a subjective guess, and often depends on temperature, strain levels, and other environmental conditions. however, a 5% elongation criterion at break is a reasonable dividing line. materials with a larger elongation can be considered ductile and those with a lower value brittle. another distinction is a brittle material's compression strength is usually significantly larger than its tensile strength. all popular failure criteria rely on only a handful of basic tests (such as uniaxial tensile and/or compression strength), even though most machine parts and structural members are typically subjected to multi-axial loading. this disparity is usually driven by cost, since complete multi-axial failure testing requires extensive, complicated, and expensive tests. the success of all machine parts and structural members are not necessarily determined by their strength. whether a part succeeds or fails may depend on other factors, such as stiffness, vibrational characteristics, fatigue resistance, and/or creep resistance. the maximum shear stress criterion, also known as tresca's or guest's criterion [4] , is often used to predict the yielding of ductile materials. yield in ductile materials is usually caused by the slippage of crystal planes along the maximum shear stress surface. therefore, a given point in the body is considered safe as long as the maximum shear stress at that point is under the yield shear stress obtained from a uniaxial tensile test. with respect to plane stress, the maximum shear stress is related to the difference in the two principal stresses. therefore, the criterion requires the principal stress difference, along with the principal stresses themselves, to be al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٠ less than the yield shear stress, this criterion has a good agreement with experimented results obtained for ductile material and due to simplicity of this criteria will be used in this study. |σ1|< σy, |σ2|< σy, |σ1-σ2|< σy where , σy = yield strength of material of uniaxial tension test as shown below, the maximum shear stress criterion requires that the two principal stresses . mathematical formulation the condition of spherical symmetry is assumed for the thick sphere with stress-strain relations and incompressibility conditions for plastic deformation. the equation is solved in the spherical coordinates. the governing equation (equilibrium equation) for the thick spherical vessel is: rdr d rdrdr d drrdividingbyandsimplified edrdrrdrrr rdrrdrrdr ddrrdddrrdrd rr rr rrrr rrr rrr )(2 0 22 )( 02)2( 02)2)(( 0)2/sin(4)())(()( 2 222 22 222 σσσ σσσ σσσσσ σσσσ θθσθσσθσ θ θ θ θ θ − =∴ =+− →−− =+++− =+++− =+++− formulation of tresca's this theory predicts that yielding will start when the maximum shear stress in the material becomes equal to the maximum shear stress at yielding in a simple tension test: 1 2 1 21 21 ±=−⇒=− yy y σσ σσ ……..(1) for thick spheres the principle stress are θσσ andr ,where r σ is compressive and θσ is tension so that: y r =− σσ θ ………….(2) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧١ case 1: internal pressure only elastic analysis: in the analysis of elastic and elastic-plastic case we must use some fundamental equations, such as equilibrium and compatibility equations. from equilibrium equation for spherical coordinates has been derived in last section, and it is given as follows: rdr d rr )(2 σσσ θ −= …………….(3) compatibility equation in terms of stresses is given by: 0)2( =+ θσσ r dr d …………….(4) in the elastic solution for this case and for other, lames equation has been used to find the solution, from equation (4), it can be seen that the amount )2( θσσ +r is independent of the radius r, there fore: )2( θσσ +r =a where a is a constant. by substitute eq. (4) into the eq. (3) and integrating, will be obtained 3 r b ar += σ ………(5) 3 2r b a −=θσ ………..(6) pr −=σ at r=a 0= r σ at r=b by substituting the above boundary condition in eq.(5) and (6), we obtain: 1 3 3 − = a b p a 1 3 3 3 − − = a b pb b thus eq. (5) and (6) can be written as: )1( )1( 3 3 3 3 − −− = r b r b p r σ ……….(7) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٢ )1( )1 2 ( 3 3 3 3 − + = a b r b p θσ …………….(8) these equations express the radial and tangential elastic stress distribution across the thickness of the wall and it is noted that the redial stress is compressive while the tangential stress is tensile. plastic analysis if the internal pressure is increased to a critical value (pe), plastic yielding begins at the radius, where the yield criterion (tresca) is first satisfied. by substituting eq. (7) and (8) into eq. (2): y r b a b p r b a b p =      −       − +      +       − 1 1 1 2 1 3 3 3 33 3 3 3 this equation reduces to pe = 3 3 3 3 1 3 2 b r a b y       − it has note that has minimum value at r=a (i.e) the difference ( )( r σσ θ − has the greatest value at r=a, this means that the initiation of the plastic zone will begin-from the inner radius when p=pe pe = )1( 3 2 3 3 b a y − with further increase in the internal pressure, the plastic zone spreads out wards and the elasticplastic boundary is a spherical trace at each stage. to find the stress distribution at the plastic zone (at each point) in this zone the yield criterion will be satisfied as will as the equilibrium equation therefore by substituting equation. from eq (1) and (2) we get: y rdr d r 2= σ then integrating ary r += ln2σ where a is a constant to be evaluated from the boundary condition, at r=a, p r −=σ then a= (-p-2yln a), and p a r y r −      = ln2σ …………… (9) to obtain the expression for θσ eq. (9) is substituted into the tresca's criterion eq. (2) we get. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٣ p a r y −+= ))ln(21(θσ ……… (10) to find the stresses in the elastic zone, lames equation are also applied as for the elastic case, but the constant will be a function of the plastic radius (c), there for the sphere is assumed to be consisted from two spheres ,the inner sphere is completely plastic and the outer sphere is completely elastic, thus the boundary condition become: 0= r σ at r=b crr )(σσ = at r=c where cr )(σ is the radial stress at r=c, and it is equal to: -( cr )(σ = )1( 3 2 3 3 b c y − from the first boundary condition: a=-b/b 3 and from second boundary condition, b=             − − )1( 1 1 3 2 3 3 3 3 3 c b b b c y then lames equations become )1( 3 2 3 3 3 3 −−= r b b c y r σ ………. (11) and )1 2 ( 3 2 3 3 3 3 += r b b c yθσ ……… (12) at the elastic-plastic boundary the stresses must satisfy the continuity condition therefore equalizing eqs. (11) and (12) at r= c, will yield 3 )1( ln 2 3 3 b c a c y p − += this equation is used to determine the radius of plastic phase. the solution is accomplished at any value of pressure (p), by solving it by using suitable numerical method residual stress analysis the residual stresses can be found by subtracting eqs. (7) and (8) from eqs (9) and (10).but in the elastic zone the residual stress can be found by subtracting eqs. (7) and (8) from eqs (11) and (12). ))(( 3 2 3 3 3 3 3 3 b a r a p p a cy e r −−−=σ ,c≤r≤b ))(( 3 2 3 3 3 3 3 3 b a r a p p a cy e +−−=θσ , c≤r≤b 3 3 3 3 ln)1(( 3 2 a r r a p py e r −−−=σ , a≤r≤c al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٤ 3 3 3 3 ln)1(( 3 2 a r r a p py e −+−=θσ , a≤r≤c case 2: external pressure only there are some case in which a sphere is subjected to external pressure, the analysis for such a case is similar to for the internal pressure case, but boundary condition are varied: elastic analysis the lames equations after applying the boundary condition becomes : )1( )1( 3 3 3 3 b a b a p o r − − =σ and ) 2 1( )1( 3 3 3 3 r a b a p o + − =θσ it is noted that the radial stress and as well as the tangential stress are both compressive while they are tensile for the case of internal pressure only plastic analysis to find the stress distribution at the plastic zone (r<c) tresca yield criteria should be satisfied as well as the equilibrium equation. thus the stresses will be: ) 3 1( 3 2 33 3 r b y b c p r −−−=σ ) 2 3 1( 3 2 33 3 r b y b c p +−−=θσ ,since these stresses must be continuous across the elastic-plastic boundary: so r=c , [ ] [ ] plasticrelasticr σσ = then -pc a y c b y b c ln2)1( 3 2 3 3 3 3 =− so p = )1( 3 2 ln2 3 3 −+= b c y b a yp by solving the above equation numerically using newton raphson method the value of the radius c can be obtain for any value of applied pressure. case 3: internal and external pressure the sphere in this case is subjected to internal and external pressure applied simultaneously. by superposition of the two elastic stresses for the internal and external pressure case and by applying the following boundary condition in to lames equation: ir p−=σ at r=a r σ =-po at r=b then al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٥ )1( 1 )1( 1 3 3 3 33 3 3 3 r a b a p r b a b p oi r −       − −−       − −=σ and ) 2 1( 1 )1 2 ( 1 3 3 3 33 3 3 3 r a b a p r b a b p oi +       − −+       − −=θσ to obtain the critical of the difference in pressures that will case the initiation of plastic zone at the inner radius (r=a),sub, θσσ andr in tresca criterion( yr =− )( σσ θ case 4: thermal loading the thermal loading, has significant effect on the value of stresses due to temperature difference that may occurs between the inner and the outer radius of the sphere, this will cause a difference in the expansion or contraction between the layers of the thick sphere, there for this will give rise-to the radial and tangential stresses. the steady state temperature distribution in the case of spherical symmetry is give by: 1 1 )( − − ×−+= a b r b tttt bab where tb &ta are temperatures at the outer and inner radius respectively. the strain in the sphere is the superposition of that due to pressure loading and thermal loading, then the elastic stress-strain equation is: t e t e r rr ανσσνε ανσσε θθ θ +−−= +−= ))1(( 1 )2( 1 where α is the linear coefficient of expansion. after appling compatibility equation and substitution t with integrating we can get the dimensionless quantity given as: )1( )( ν α β − − = ba tt the radial stress and as well as the tangential stress are given by the equations below:             − − − − − −= 1 1 1 1 3 3 3 3 a b r b a b r b e r βσ             − + − − − −= 1 1 2 1 1 2 3 3 3 3 a b r b a b r b eβσ θ result and discussion the calculation show that the internal pressure required to initiate the plastic zone from the inner radius is pi=14 mpa and the state of total plasticity is reached when pi=33.2mpa, because of increasing the loading of vessel, the volume increase, which leads to plastic deformations take al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٦ place. at internal pressure pi=8mpa, the whole sphere is in fully elastic state. this pressure is lower than the pressure needed to initiate the plastic deformation at the inner surface, figure(1) shows the non-dimensional radial and tangential stress distribution along the thickness of the sphere, we conclude from that when the external pressure increased beyond the critical value of the pressure the plastic zone will propagate outward that’s leads to increasing the radial stress . figure (4) shows the variation of the dimensional residual radial and tangential stresses across the thickness of the sphere when it is loaded with pressure p=30 map. we see that the hoop stress increase during the thickness of the sphere because of the residual stress distribution increase due to overloads. figure (5) show the non-dimensional radial and tangential stress distributions due to thermal loading ,we see that the hoop stress is larger then radial stress because of the coefficient of thermal expansion mismatch between different phases. figure (6) show the elasto-plastic state of stresses for external pressures of 20mpa this figures also show the propagation of plastic zone as the pressure increases. due to the plastic area increase leads to yielding take place. conclusions for the internal pressure case it can be observed that the plastic zone starts at the inner radius and spreads outward as the pressure increase, also there is a direct proportionality between elastic boundary radius and internal pressure. the residual stresses increases as the amount of plastic deformation increases. there is a direct proportionality between the internal pressure and the value of the residual tangential. for thermal loading it is noted that the radial stress is negative and reaches a maximum value between the inner and the outer radius. this maximum stress will be at r/b=0.64.it also observed those values of stresses increases as temperature difference increases. effects of residual stress may be either beneficial or detrimental, depending upon the magnitude, sign, and distribution of the stress with respect to the load-induced stresses. very commonly, the residual stresses are detrimental, and there are many documented cases in which these stresses were the predominant factor contributing to fatigue and other structural failures when the service stresses were superimposed on the already present residual stresses. references [1] pavel elesztos ladislav ecsi ‘’ stress test of spherical pressure-retaining vessels with hydrocarbon gases’’ [2] dechant,k.e.: effects of high pressure testing technique on pipelines. 1996 omae volume v, pipeline technology, asme 1996. [3] hossein mahbadi mohamad r. eslami ‘’ elastic-plastic-creep cyclic loading of thick pressure vessels based on the frederick-armstrong kinematic hardening model’’paper # f05-7 [4] faruk sen and metin sayer ‘’ elasto-plastic thermal stress analysis in a thermoplastic composite disc under uniform temperature using fem’’mathematical and computational applications, vol. 11, no. 1, pp. 31-39, 2006. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٧ 0.40 0.60 0.80 1.00 -0.40 -0.20 0.00 0.20 0.40 figure (1): pressure and internal hoop and axial stresses. 0.40 0.60 0.80 1.00 -0.4 -0.2 0 0.2 0.4 y/σ r/b θσ r σ figure (1): elastic stress distribution for internal pressure(pi=8 mpa) θσ r σ figure (2): elastic stress distribution for internal pressure(pi= 18 mpa) y/σ r/b 0.40 0.60 0.80 1.00 -0.80 -0.40 0.00 0.40 0.80 plastic zone r/b elastic zone y/σ θσ r σ figure (3):elastic-plastic stress distribution for( pi=25 mpa) 0.40 0.60 0.80 1.00 -1.50 -1.00 -0.50 0.00 0.50 θσ r σ r/b y/σ figure (4):residual stress distribution for internal pressure ( pi=30 mpa) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٧٨ 0.40 0.60 0.80 1.00 -0.02 0.00 0.02 0.04 0.06 θσ r σ r/b y/σ figure (5):radial and tangential stress distribution for thermal loading ( ta=500,tb=20 ) 0.40 0.50 0.60 0.70 0.80 0.90 -1.60 -1.20 -0.80 -0.40 0.00 r/b y/σ θσ r σ figure (6):elastic –plastic stress distribution for external pressure(po=20 mpa) al-qadisiyah journal for engineering sciences 13 (2020) 031–036 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: adnan.alsibahy@qu.edu.iq (adnan al-sibahy ) https://doi.org/10.30772/qjes.v13i1.647 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. structural behavior of novel ecc short columns subjected to eccentric loading safaa mashshay a, adnan al-sibahya a* a civil engineering department, college of engineering, the university of al-qadisiyah, iraq. a r t i c l e i n f o article history: received 05 october 2019 received in revised form 16 january 2020 accepted 28 january 2020 keywords: ecc columns hybrid ecc eccentric columns a b s t r a c t this study was undertaken in order to investigate the structural behaviour of novel engineering cementitious composites (ecc) columns subjected to eccentric loading. these columns were experimentally formulated using a hybridization of steel and polypropylene fibres. two ratios were adopted for the steel fibres of 0.5% and 1%, whilst the polypropylene fibre was kept to be constant at a ratio of 0.5% for all of the ecc columns. the eccentric loads were applied at two eccentricities: small (h/6) and large (5h/12). a comparison was also made with the behaviour of self-compacting concrete and traditional ecc columns containing either steel or polypropylene fibres. the vertical and lateral deformations as well as the maximum load at failure were noted. the results obtained showed that the hybrid ecc columns exhibited higher load carrying capacities when compared with those of both self-compacting concrete and traditional ecc columns. the percentage increase was 30%. the hybrid ecc column samples containing 1% steel fibre did not show a signification difference in the load-deformation behaviour when it compared with that containing 0.5% steel fibre. the values of eccentricity governed the global behaviour of the tested columns. the predicated load carrying capacity of the ecc columns needs a magnification factor in case of concentric test, and to take into account the existence of fibres ratio when calculating the area of steel reinforcement for eccentric loading. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction developing the behaviour of structural members is the main concern for the most of the published research works in the construction field nowadays. in general, such developing can be obtained either through improving the composition of these members or by updating the implementation techniques used. reinforced columns are part of these structural members which generally referred to as compression members [1]. in some cases, columns may carry bending moments about one or both axes of the cross section. the general behaviour of columns is governed by the amount of steel. reinforcement available for both longitudinal and transverse directions, the strength of the concrete used, conditions of the supports and the slenderness ratio [2]. depending on the nature of the imposed load, the failure modes of the reinforced concrete columns are in the forms of crushing, shearing and bending for the loading cases of concentric, transverse and eccentric, respectively [3-5]. a combined failure modes may also be found for the same case. several previous studies were carried out for enhancing the integrity of the reinforced concrete columns under various conditions of loading. in the last decade, there was a tendency for replacing the conventional concrete with engineering cementitious composites (ecc) [6-15]. however, it’s used in column elements is less than that for flexural structural members [11]. except for the absent of coarse aggregate, this material has a similar constituents as for the fiber reinforced concrete (frc). nevertheless, ecc usually exhibits strainhardening after the propagation of the first crack rather than of the usual tensionhttp://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i 32 safaa mashshay a, adnan al-sibahya / al-qadisiyah journal for engineering sciences 13 (2020) 031–036 softening [6]. although the desired advantages of ecc mentioned above, improving its properties still needs for investigation. since there is no published research work about using hybrid fibers in ecc, so it is necessary to undertake such trend into consideration. in this paper, using hybrid steel and polypropylene fibers at different ratios in the formulation of reinforced column members has been experimentally investigated. these columns were tested under the actions of eccentric loading. a comparison was also made with the traditional ecc containing either steel or polypropylene fibers as well as with the behaviour of reinforced self-compacting concrete columns. some expressions were suggested to identify the general behaviour under the test conditions. 2. experimental work 2.1. materials used an ordinary portland cement by lafarge company was used in this study. it was compliant with en bs 197-1 [16]. locally available natural sand from al-najaf quarries was used as a fine aggregate to produce both of the ecc and self-compacting concrete specimens. it has a maximum particle size of 4.75 mm. on the other hand, crushed gravel with a maximum size of 10 mm was used as a coarse aggregate to produce the self-compacting concrete specimens only. it was provided from al-nibaei quarry. both types of aggregate are consistent with the grading limits of en bs 882.1992 [17] and they have sulphate contents of 0.216% and 0.082%, respectively. a limestone powder was used as a filler in preparing of the self-compacting concrete columns, while silica fume was used in producing of ecc columns. for all of the column samples, the daracem sp6 superplasticizer admixture of the sulphonated naphthalene formaldehyde condensate snf [18] was used, its maximum chloride and alkali contents were < 0.1% and 0.5% by mass, respectively. two types of fibres were used, namely steel and polypropylene fibres. they were incorporated in the ecc column samples in different ratios as a percentage from the total volume of the mixture. the aspect ratios of the steel and polypropylene fibres were 65 and 375, respectively. two different sizes of deformed steel bars of ø10 and ø12 were used in all of the column samples as the transverse and main reinforcements, respectively. the values of the yield and ultimate strength of the former steel bars were 480 mpa and 700 mpa, respectively. 2.2. selection of the concrete mix for the purpose of comparison, a self-compacting concrete was selected as a reference mix. the reason for that is the ecc usually has high flowability and its need for compaction effort is usually minimal [15]. on this basis, the composition of the reference mix was selected to be in the strength level of 50 mpa at 28 days. this in turn gives a mix proportion of 1:1.5:1.6 with cement content and w/c ratio of 430 kg /m3 and 0.42, respectively. both of limestone and superplasticizer were used in this mix with ratios of 0.2% and 1.5%, respectively. on the other hand, the suggested mix proportion of cement: 1, silica fume: 0.22, sand: 2, w/c : 38% by volume was selected for ecc. this employ 570 kg /m3 cement, 1140 kg /m3 sand and 124 kg /m3 silica fume. two groups of the hybrid fibres were used in the ecc ; the first incorporated 0.5% steel and 0.5% polypropylene fibres, and the second incorporated 1% steel and 0.5% polypropylene fibres. the former fibre percentages were recommended by previous studies [1, 5]. 2.3. description of the tested samples the experimental programme comprised of testing eight column samples. all of the tested columns were square in shape. the height of columns was selected to be 1200 mm. the column samples with a square cross section of 200*200 mm. this in turn gives a slenderness ratio of 20. a minimum steel area (as ≥ 1%) was used for reinforcing the longitudinal direction, namely 4ø12mm. whereas, 12 stirrups were adopted using ø10@100mm c/c as a reinforcement for the transverse direction. the calculations for both of the former reinforcements was based upon the requirement of aci 318m-11 code [19]. in order to avoid the concentration of stresses near the loading plate, the upper and lower parts of the columns were expanded to be in a tapered shape. same technique was also used by [15]. figure 1 shows the details of the tested columns. figure 1. details of the tested columns 2.4. mixing, casting, curing operations and the tested parameters as shown in figure 2, for all of the column samples, the mixing, casting and curing operations were carried out based upon the procedure suggested by bs en 12390-2 (bsi, 2009c) [20]. before running the test, all of the column samples were capped using rapid cement mortar, then they were painted in a white colour. during the lifting process, the location of columns was centrally adjusted with the centre line of the testing machine. in order to achieve the objective of this study, the nature of the applied load was in two categories; namely small (1/6 h) and large (5/12 h). the tested columns were designated based on the type of column, nature of loading and type and ratio of the fibre used, as illustrated in table 1. the applied load was manually controlled and a loading rate of 0.5 mpa/sec was adopted. during running of the test, both vertical and lateral deformations were measured using lvdt at the top and mid-height of the column. for each column, the test was performed until failure and the load-crack history was recorded. in addition, the failure mode and critical zones were monitored for each case. 33 safaa mashshay a, adnan al-sibahya / al-qadisiyah journal for engineering sciences 13 (2020) 031–036 table 1. the designation of the tested columns with their parameters 3. results and discussions the results obtained for the load-deformation relationships for various column samples are shown in figures 3 to 8. a superior behaviour was noted for the hybrid ecc columns in terms of deformation and load carrying capacity aspects compared with those containing self-compacting concrete and those of the traditional ecc. for the concrete and hybrid ecc columns subjected to eccentric load of h/6, the results obtained are presented in figures 3and 4. both of hybrid ecc columns reached the level of 1400 kn load carrying capacity with a notable increase for the sample containing 1% steel fibre. on the other hand, the concrete column (cbe1) exhibited a lower failure load at 1070 kn. this in turn gives percentage increase of 30% for the hybrid ecc columns .identical shape for the load-deformation curve in both directions was observed. the end values of vertical deformations for the columns samples of concrete, hybrid ecc with 0.5% steel fibre and that of 1% steel fibre were 5mm, 9mm and 13mm, respectively. the corresponding values for the lateral deformations were 5mm, 12mm and 17mm, respectively. figures 5 to 8 show a detail comparison for all of the tested columns subjected to eccentric load of 5h/12 in terms of load-vertical and lateral deformations, respectively. the role of steel fibre was clear regarding improving the load carrying capacity feature. the traditional ecc column with 1% steel fibre exhibited the highest strength capacity at failure load at 925 kn. if the polypropylene fibre is used the aforementioned strength capacity will be reduced. this could be explained by two issues: the first is related to the lower strength capacity of the polypropylene fibre itself in both compression and tension aspects when compared with those for steel fibre; and the second, is related to the present of such kind of fibre leads to the formation of entrapped voids within the ecc composition which represents a weakness point that results in reducing the final strength of the column sample. this behaviour was clearly shown for the column containing polypropylene fibre alone, in which the load-bearing capacity reached 750 kn, meaning 20% percentage reduction compared with that of steel fibre. if combination of both fibres is used as in the ebe2-1 s-0.5 p and ebe2-0.5 s-0.5 p columns, the load carrying capacity will increase with a percentage equivalent to the added ratio of steel fibre. in general, all of the column samples incorporating fibres showed vertical deformation of 11mm with a parentage increase of 50% compared with that of concrete column. similar attitude was also noted for the lateral deformation recorded at the mid height of the column. however, the column formulated with polypropylene fibre alone revealed the highest lateral deformation due to its capability to reduce the width of cracks. consequently, higher lateral buckling can be achieved prior to the column failure. the hybrid columns have more lateral ductile behaviour than that containing steel fibre alone. the percentages increase in the value of lateral deformation for the ebe2-0 s-0.5 p, ebe2-0.5 s-0.5 p, ebe2-1 s-0.5 p and ebe2-1 s-0 p compared with that of concrete sample were 127%, 171%, 180% and 116%, respectively. figure 2: preparation of moulds, mixing and curing operations figure 3: load-lateral deformation of columns subjected to eccentric load of h/6 figure 4: load-vertical deformation of columns subjected to eccentric load of h/6 no. sample type of column cross section mm e/r steel fibre ratio% polypropylene fibre % 1 ebe1-0.5s-0.5p ecc 200*200 0.4 0.5 0.5 2 ebe2-0.5s-0.5p 200*200 0.93 0.5 0.5 3 ebe1-1s-0.5p 200*200 0.4 1 0.5 4 ebe2-1s-0.5p 200*200 0.93 1 0.5 5 ebe2-0s-0.5p 200*200 0.93 0 0.5 6 ebe2-1s-0p 200*200 0.93 1 0 7 cbe1 cc 200*200 0.4 0 0 8 cbe2 200*200 0.93 0 0 ● cbe2  ebe2-0.5s-0.5p  ebe2-1s-0.5p ● cbe1  ebe1-1s-0.5p  ebe1-0.5s-0.5p ● cbe1  ebe1-1s-0.5p  ebe1-0.5s-0.5p 34 safaa mashshay a, adnan al-sibahya / al-qadisiyah journal for engineering sciences 13 (2020) 031–036 figure 5: load-vertical deformation of columns subjected to eccentric load of 5h/12 figure 6: load-lateral deformation of columns subjected to eccentric load of 5h/12 figure 7: load-vertical deformation for various types of columns subjected to eccentric load of 5h/12 figure 8: load-lateral deformation for various types of columns subjected to eccentric load of 5h/12 figure 9: failure modes for the columns under eccentric loading 5h/12; (a) front view, (b) back view ● cbe2  ebe2-1s-0.5p  ebe2-0.5s-0.5p ● cbe2  ebe2-0.5s-0.5p  ebe2-1s-0.5p ● cbe2 ebe2-0.5s-0.5p △ ebe2-1s-0p  ebe2-0s-0.5p ◊ ebe2-1s-0.5p ● cbe2 ebe2-0.5s-0.5p △ ebe2-1s-0p  ebe2-0s-0.5p ◊ ebe2-1s-0.5p b a 35 safaa mashshay a, adnan al-sibahya / al-qadisiyah journal for engineering sciences 13 (2020) 031–036 for the eccentric loading, composite failure modes of compression and bending were noted for both of hybrid ecc columns , as shown in figure 9a and b. multi cracks were located underneath the tapered part and at the mid height of the column which explain the role of the fibres in controlling the global failure. more cracks along the column height were noted for all of the ecc samples compared with that of concrete sample (cbe2). this is indicative for less spacing of cracks which can be achieved when the steel and/or polypropylene fibres are used. spalling behaviour was also observed for the concrete column sample. based upon the preliminary mechanical strength testes performed on the concrete, traditional ecc and hybrid ecc cube samples, the results of the compressive strength values are shown in table 2. table 2. the values of compressive strengths for different composition of columns at 28 days age for the case of biaxial bending, bresler [2] suggested reciprocal method to predict the load carrying capacity for the eccentric loading, as in eq. 1 table 3. the calculated and measured results of load carrying capacity for the eccentric loaded columns (1) where 𝑃𝑛 is the approximate value of ultimate load in biaxial bending with eccentricities 𝑒𝑥 and 𝑒𝑦 ; 𝑃𝑛𝑥0 is the ultimate load when only eccentricity 𝑒𝑦 is present; 𝑃𝑛𝑦0 is the ultimate load when only eccentricity 𝑒𝑥 is present; and 𝑃0 is the ultimate load for concentrically loaded column. in this study, uniaxial loads were adopted, so 𝑃𝑛𝑦0 was only available for estimation. based upon the column strength interaction diagram for the rectangular section with bars on end faces and 𝛾 = 0.45 and 0.6, the predicted values of load carrying capacities for the eccentric loading columns against their experimentally measured results are presented in table 3. it can be seen that the predicted values of load carrying capacities for both of concrete columns (i.e. cbe1 and cbe2) were close to those measured values. on the other hand, none of the predicated values of ecc columns was in agreement with their corresponding experimental result. in order to improve the accurate of calculations, a modified technique was suggested to calculate the load carrying capacity from the reciprocal method. this was throughout incorporating the fibre ratio in the term of a_st⁄bh. the latter is one of the main components of the interaction diagram. this in turn means increasing the area of steel reinforcement in an equivalent percentage to that of the fibre used. such modification was only applied in calculation of the load carrying capacity of the ecc columns and the results obtained are shown in table 3. close agreement has been achieved with respect to the experimental measurements. 4. conclusions this study is an attempt to produce a new formulation of ecc columns throughout hybridization process using both steel and polypropylene fibers followed by a structural evaluation for their behaviour under eccentric loading. the main significant findings of this study can be summarized as follows: 1higher load carrying capacities were observed for the hybrid ecc columns compared with those of self-compacting concrete under eccentric loading scenarios. 2both of the hybrid ecc columns behaved in a similar manner in terms of load-deformation criteria with slight increase in the value of lateral deformation noted when 1% of steel fibre is used. 3the role of steel fibre was demonstrated in preventing the propagation of cracks, whilst polypropylene fibre works on minimizing the crack width. 4the maximum load at failure was clearly reduced with an increase in the value of eccentricity. the percentage of decrease reached about 45%. 5in case of eccentric loading, the predicted values of load carrying capacities for ecc columns the fiber ratio should be taken in consideration in order to compute the maximum load at failure. 6generally, composite compression and flexural failure modes were observed for the hybrid ecc columns with eccentric loading incorporated multi cracks localized approximately at mid-height of the column. references 1. adnan al-sibahy, behaviour of reinforced concrete columns strengthened with ferrocement under compression conditions: experimental approach, world journal of engineering and technology, 2016, 4, 608-622. 2. nilson, a.h. and darwin, d. (1997) design of concrete structures. 5th edition, mcgraw-hill. 3. li, j.b., gong, j.x. and wang, l.c. (2009) seismic behavior of corrosiondamaged reinforced concrete columns strengthened using combined carbon fiber-reinforced polymer and steel jacket. construction and building materials , 23, 2653-2663. 4. zhou, x.h. and liu, j.p. (2010) seismic behavior and strength of tubed steel reinforced concrete (src) short columns. journal of constructional steel research, 66, 885-896. http://dx.doi.org/10.1016/j.jcsr.2010.01.020. 5. polies, w., ghrib, f. and sennah, k. (2010) rehabilitation of interior reinforced concrete slab-column connections using cfrp sheets. construction and building materials , 24, 1272-1285. http://dx.doi.org/10.1016/j.conbuildmat.2009.12.008. no. symbol cube compressive strength (mpa) equivalent cylinder compressive strength (mpa) 1 cc 59.6 70.1 2 ecc-0.5 s-0.5 p 53.9 63.4 3 ecc-1 s-0.5 p 56.3 66.2 4 ecc-1 s-0 p 62.6 73.6 5 ecc-0 s-0.5 p 50.4 59.3 no. sample experimentally measured load carrying capacity, (mpa) direct calculation from reciprocal method suggested modification for the calculation from reciprocal method calculated load carrying capacity using strength interaction diagram [2]mpa percentage difference, % calculated load carrying capacity using strength interaction diagram [2]-mpa percentage difference, % 1 ebe1-0.5 s-0.5 p 1371 1089 -21 1500 +9 2 ebe1-1 s-0.5 p 1450 1089 -25 1500 +3 3 cbe1 1094 1089 000 1089 0 4 ebe2-0.5 s-0.5 p 813 552 -32 827 +2 5 ebe2-1 s-0.5 p 850 552 -35 827 -3 6 ebe2-0 s-0.5 p 795 552 -31 827 +4 7 ebe2-1 s-0 p 941 552 -41 827 -12 8 cbe2 624 552 -12 552 -12 36 safaa mashshay a, adnan al-sibahya / al-qadisiyah journal for engineering sciences 13 (2020) 031–036 6. j. mater, engineering cementitious composites for structural applications, civ. eng. 1998.10:66-69.7. michael d. lepech , victor c. li., application of ecc for bridge deck link slabs, materials and structures (2009) 42:1185–1195. 8. jun zhang, christopher k.y. leung, yuan gao, simulation of crack propagation of fiber reinforced cementitious composite under direct tension, engineering fracture mechanics 78 (2011) 2439–2454. 9. yixin chen, jing yu, christopher k.y. leung, use of high strength strainhardening cementitious composites for flexural repair of concrete structures with significant steel corrosion, construction and building materials 167 (2018) 325–337. 10. fang yuan, et. al., mechanical behaviors of steel reinforced ecc or ecc/concrete composite beams under reversed cyclic loading, doi: 10.1061/(asce)mt.1943-5533.0000935. 11. jiajia zhou, et. al., mechanical behavior of fiber reinforced engineered cementitious composites in uniaxial compression, journal of materials in civil engineering, doi:10.1061/(asce)mt.1943-5533.0001034. 12. fang yuan, et. al., elastoplastic time history analysis of reinforced engineered cementitious composite or engineered cementitious composite– concrete composite frame under earthquake action, advances in structural engineering 1–13, 2016. 13. zhong tao, et. al., experimental behaviour of concrete-filled stiffened thinwalled steel tubular columns, thin-walled structures 45 (2007) 517–527. 14. chung-chan hung, fuo-yao hu, behavior of high-strength concrete slender columns strengthened with steel fibers under concentric axial loading, construction and building materials 175 (2018) 422–433. 15. fang yuan, et. al., behaviors of steel-reinforced ecc columns under eccentric compression, construction and building materials 185 (2018) 402– 413. 16. en bs 197-1. cement, part 1: compositions, specification and conformity criteria for common cements. british standards; 2000. 17. en bs 882.1992: specification for aggregate from natural sources for concrete. british standards; 1992. 18. bs en 934-2: admixtures for concrete, mortar and grout, part 2: concrete admixtures – definitions, requirements, conformity, marking and labelling. bsi, 2009, london, uk. 19. aci 318m-11 code, building code requirements for structural concrete (aci 318m-11), aci committee 318, american concrete institute, 2011. 20. bs en 12390-2. making and curing specimens for strength test. british standards, 2009. article al-qadisiyah journal for engineering sciences 13 (2020) 215–222 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: akramalkhanfar@gmail.com (akram luaibi) https://doi.org/10.30772/qjes.v13i3.661 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. cooling process of gas turbine blade: a comparison study akram luabi a,b*, naseer hamza a a mechanical engineering department, university of al-qadisiyah, ad'diwaniyah 58001, iraq b al-diwaniyah gas turbine power plant, ad'diwaniyah 58001, iraq a r t i c l e i n f o article history: received 02 june 2020 received in revised form 10 july 2020 accepted 20 july 2020 keywords: gas turbine blade film cooling internal cooling a b s t r a c t the gas turbine engines are occupied an important sector in the energy production and aviation industry and this important increase day after day for their features. one of the most important parameters that limit the gas turbine engine power output is the turbine inlet temperature. the higher is the turbine inlet temperature, the higher is the power output or thrust but this increases of risks of blade thermal failure due to metallurgical limits. thus the need for a good and efficient process of blade cooling can lead to the best compromise between a powerful engine and safe operation. there are two major methods: film or external cooling and internal cooling inside the blade itself. . in the past number of years there has been considerable progress in turbine cooling research and this paper is limited to review a few selected publications to reflect recent development in turbine blade film cooling. the maximum drop in the surface temperature of the gas turbine blade and associated thermal stress – due to incorporating cooling systemswere 735 ˚c, 1217 n/mm2 respectively. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the experimental, theoretical, and computational in the recent different investigations relevant to this work were presented such as the effect of raise the number of cooling duct and the coupled heat transfer (conjugate ) of gas turbine bucket. literature scanning mentions that conjugate heat transfer cht examination performs an important function to guide the temperature distributions for the heat transfer representations. the turbine inlet temperature is the most important parameter that influences the thermal efficiency of the power plants. gas turbines are run at high inlet temperatures to satisfy the requirements of the power plants like the improved thermal efficiency and increasing the production of the energy. innovative internal and external cooling methods are introduced for the new gas turbine engines to cool the blades and avoid material failure at extreme temperatures. improved cooling techniques will allow the turbine operation to be closer and closer to the maximum permissible temperature for combustion and thus meet the power output requirement, especially at peak load. the cooling systems in the gas turbine blade are very complicated even that some times each application has its cooling scheme. fig. 1 show the cooling passages inside the blade. the mathematical model of cooling systems is based on the forced convection heat transfer equations majorly and related formulas. figure 1. stage-1 high-pressure turbine rotor blade for the ge cf6 engine. [1] http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 216 akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 there are many surveys done to scan the outcomes of researchers in the field of gas turbine technology and to continue this effort, this study aims to compare recent studies especially to cover recent last years. 2. analysis of turbine blade cooling mechanisms in the brief review below some of the pertinent work available in the open literature. at the summary review below some of the relevant study which available in the modern literature. 2.1. external cooling (film cooling) film cooling is used to protect a solid surface from a high temperature of the mainstream by releasing a coolant on the surface. this secondary fluid can be considered as a heat sink for the heat flow from the hot mainstream or as an insulating layer between the hot mainstream and the surface. few researchers performed experimental work for instance many references cited the work of luckey et. al. [2] empirical examination is used to simulate the airfoil profile of leading edge by using the stagnation zone of a cylinder mounted in a cross-flow a cylindrical with some of film cooling lines. they associated their outcomes for the optimal value of the blowing ratio and insertion angle. experiments were fulfilled with an individual row of spanwise angled cooling channels for a domain of the coolant blowing ratio with independent flow-to-wall temperature. the local heat flux data measurements are offered for injection angles of cooling channel at 25°, 35°, and 45° with the row of passages located at three sites comparative to the stagnation line on the drum. results see that path of (channel-to-channel) variations of heat flux shorthand due to film cooling and indicate the optimum performance for film cooling conditions mehendale et. al. [3]. yao et al. [4] carried out an experimental investigation to study the performance of the cooling film for a consoles of single row set on a curved plate model in order to simulate the suction side of the blade. numerical simulation was accomplished in order to disclose the detailed feature of the consoles film cooling (consoles on a curved surface). the results were compared to a mode of cylindrical holes. martini et al. [5] studied the heat transfer and the cooling performance of the film of the cutback of the gas turbine airfoil trailing edge by using ir thermography method for different forms of internal cooling. the internal design effect on the cooling effect for the ejection slots was studied as well. the results showed that the shedding of the vortex from the side lip pressure was the main reason beyond the degradation in the cooling effectiveness of the film. je-chin han et al. [6] performed the experiments in three zones of a stator blade of the gas turbine which are blade platform, span, and tip. the blade platform and span investigations were done on the rotor blade of the high pressure turbine in median flow situations. film-cooling performance or degree of cooling was appreciated in terms of cooling duct form, blowing ratio, and mainstream to coolant density ratio. the blade crest study was carried out in a blow-down flow turn in a transonic flow medium. the cooling degree was valued in terms of tip clearance and blowing ratio. confined heat transfer coefficient evaluations were also performed. mainstream pressure wastage was measured for blade platform and tip filmcooling. results showed that the blade platform cooling demands a collection of purge flow at upstream and discrete film-cooling channels downstream to cool the total platform. the formed cooling passages provided that vast film covering and higher film-cooling performance than the circular passages whereas also producing minimum mainstream pressure losses. colban et al. [7] performed the film-cooling effectiveness of cylindrical channels and compared them with the vane-formed ducts on a turbine blade end wall. they had several experimental data for setup closes to that as the present work, with two passages having the same layout, one with circular holes and the other with vane-formed ducts. the missing aspect in the research that has been done in the examination into the effect of variance channels configuration and form on the blade cooling of the gas turbine and comparing the result in obvious parameters. yang et al. [8] anticipated the cooling effectiveness of the film and the coefficient of heat transfer for three different types of the arrangement of the film and the hole. in the first one, the holes were designed to be located on the tips mid-camper line. in the second, the holes were created to be set in the stream of leakage flow (on the tip) and the region of heat transfer. while the third arrangement was the combination between the first and the second, respectively. the results of this study showed that the second configuration provided better performance than the others. acharya et al. [9] presented that the cooling injection of the film decreased the ratio of the local pressure and changed the leakage vortex nature. high adiabatic effectiveness of the film and low coefficient of heat transfer were noticed lengthways the trajectory of the coolant with very small values of the cooling jet cross spreading. better efficiency of the downstream of the coolant might be provided by increasing the gap of the tip. however, at the smallest gap, the coolant directly impinged on the shroud surface resulting in a high effectiveness at the point of impingement. hohlfeld et al. [10] presented a numerical study about losses of the cooling flow and the microcircuit channels. the advantages of the cooling flow of the external film that resulted from using microcircuit was presented. the results predicted that the microcircuit exits blowing and the cooling of the mid chord were independent. besides, for all modes of the cooling of the microcircuit film presented in this study, aside vortex of the pressure was developed. in addition, good cooling effectiveness was obtained from the exiting of the holes of the dirt purge when the tip gap was small. however, low cooling effectiveness was observed for the larger gap of the tip. goldstein r. j et. al. [11] presented the cooling of the film by introducing fluid (secondary) along the high temperature surface in order to protect these surfaces. ito et al. [12] presented a film cooling effect on the blade of a gas turbine by calculating the cooling effectiveness of the film holes for the surfaces of different convexities and curvatures. kumar et. al. [13] presented a detailed investigation about film cooling of the blades of a gas turbine. ansys workbench v. 15.0 software was used for the numerical simulation and solving the governing differential equations. effect of using different configurations of the holes that changes the cooling effectiveness was also investigated. the results of this study showed that the conclusions presented by other researchers about using cooling channels were correct reasonable. in addition, the increasing in cooling efficiency due to using cooling channels was due to heat transfer enhancement. increasing the flow rate of the mass was a good factor for increasing cooling effectiveness (an optimal mass flow rate was required). 2.2. internal cooling (cooling holes) khari brahmaiah et.al. [14] discuss the four various models to analyze the heat transfer through a gas turbine blade, blade is analyzed without and with channels that have different hole numbers (5, 9&13). according to this akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 217 study, the temperature distribution and transfer rate for the blade with 13 holes are optimal. structural analysis is done by the ansys software with blade at different materials, inconel-718 and chromium steel. the thermal properties of inconel-718 material are better whereas induced stresses are lesser as compared to the chromium steel. josin et al. [15] showed a comprehensive study and design of the cooling passages of the blades of a gas turbine. the geometrical modeling was created by catia v.5. both thermal and structural analyses were performed by using ansys 14.0 finite element software which is commercially available in its student edition. gdt-11, u-500, and in-738 alloy were considered as the material that used in this study. the first step of the analysis was to choose the material that shows better results for the first stage of the turbine blades. the next step was the modeling of the blade by modifying its geometry into a serpentine model in addition to increase the number of the hole. temperature distribution from the thermal analysis and maximum elongation from the structural analysis were calculated and observed at the tip and the root sections of the blade, respectively. the comparisons between the three materials used in this study showed that gtd-11 offered the maximum deformation, maximum stresses, and could withstand higher temperatures around 8570 co without any damage to the blade because of the higher melting temperature. öztekin et al. [16] observed that the numerical results are in perfect coincidence with experimental results when developed wall functions and the model of k-ε turbulence in the principle of local alteration of the pressure coefficient. maximizing the dimensionless blade-to surface space produced deficiency the coefficient of pressure (cp) at the stagnation end. b.h. dennis et al. [17] presented an optimized design for the cooling passage of a gas turbine blades by using the reduced method of conjugate heat transfer. the compressor last stage in the gas turbine presented in this study provided the cooling air. it was noted that the shape of the cooling channels and its location affected the heat transfer amount, temperature gradient inside the blades, temperature distribution, and cooling air-mass flux. air was designed to flow inside the blades from its root and leave from its tip or trailing and leading edges. ni et al. [18] simulated a methodology and an analysis of heat transfer and applied it for studying the cooling process of an air force film of a turbine van with 648 holes. the results of this work showed that air flows from the holes (cold air) created a protective layer all around the surface of the airfoil and the end walls. lower temperature values were noticed on the entrance to the holes as well as the surfaces that were subjected to a high temperature hot gas. choo et al. [19] tested the micro-scale jet impingement on a heated flat plate and estimated the characteristics method of heat transfer by using correlation equations with experimental data on average and local nu number in terms of reynolds number and blade-toplate distance. numerical study, using reynolds-averaged navier-stokes (rans), coupled with the k-ε model has been appointed as an important norm design and the simulation analysis. b. deepanraj et al. [20] used a numerical analysis thermal effectiveness due to loading status. titanium aluminum alloy properties and variant cases with different hole numbers of (7, 8, 9, 10, 11, and 12) were performed. thermal stress, temperature distribution, and deflection were obtained using ansys software for several number of channels. the results explained that the decrease in the temperature values and the reduction in the temperature drop was motivated by the increasing number of the blade channels. reddy et al. [21] has tested the stainless steel thermal and structural analysis. four variant cases containing of blade without and with different number of passages (7, 8, 9, and 10) were examined to discover the perfect cooling channels number. it is found that as the number of cooling channels increases the temperature distribution rise up. the solid works software is used to simulate the structural analysis. the results showed that the blade with 10 № of holes is more stresses than the other models. lastly, the model with nine holes has produced the optimum solution. a.b. moskalenkoa et al. [22] the numerical calculations were carried out using cfd based on the fem. the coefficient of heat transfer and heat distribution of the bucket from the cooling domain to the cooling hole wall were selected as the standard of cooling efficiency. abdulla r. al ali et al. [23] was fulfilled the numerical analysis of different heat transfer methods of jet impingement on a half-circular face. the comparison of these cases was based on the effective heat transfer by obtaining top nusselt number and minimum surface temperature as heat transfer by convection is becoming the dominant situation and by compared between central and side jet configuration based on average nusselt number at different reynold numbers. the results were obtained to be in convention with the experimental investigation. for more highlight physics of the flow, a sensibility test on the jet impingement configuration and flow status were specified and was demonstrated to the internal cooling of the first stage bucket. harsha d a et al. [24] investigated the effects of material on thermal and structural analysis of blade designed with 12 holes as shown in fig. 2. he compared the titanium alloy with aluminum and observed that the total rate of heat transfer and the leading edge temperature were maximum and minimum for the 12 holes blade, respectively. figure 2. geometry model with boundary walls [24]. soo-yong cho. et al. [25] investigated the conjugate heat transfer on a blade of a gas turbine for various cases without and with different number of cooling channels. it was noted that the temperature of the leading edge was minimum while the overall heat transfer rate was higher for the blade within 13 holes. the analysis was examined for two alloy constructions, inconel 718 and chromium steel. the results showed the maximum value of the heat flux for the inconel 718 blade with 13 channels and the thermal stresses were under allowable limits. k. mazaheri et al. [26] examined the optimization of the configuration of the blade cooling holes. the goal was maximization of the temperature distribution. the conjugate heat transfer technique was applied to perform the analysis. the internal and external heat transfer was performed in a central scheme to find out the optimal function. results showed that the method of temperature gradient in moving the fourth hole a far from the trailing edge and also reducing the 218 akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 volume of all holes, while the criterion of maximum temperature results maximize in their volume. a. ziaei-asl et al. [27] studied the effects of varying the thickness of a thermal barrier coating (tbc) on the style of temperature distribution for a turbine blade. the blade was modeled to contain several cooling channels to increase the cooling efficiency. several micro-passage were designed to be located on the blade tip in order to take out the coolant. the tbc is considered as an elastic material and the elastic modulus was computed from the stress-strain curve. a.hasanpour et al. [28] solved the conjugate heat transfer of a metal blade designed in four different hole shapes and configurations. four cylindrical holes in shape with kε (rke) for turbulence modeling were used in this work. couch. et. al. [29] examined a novel technique for cooling called a microcircuit technique. this technique combines the injection of the pressure side and the internal convection on the tips of the turbine blades. the dirt purge holes were designed to be on the tip to expel the dirt from the blade. in order to check the effectiveness of the holes on the tip along with the suggested microcircuit technique, the design was tested experimentally using wind tunnel tests. both blowing ratio and gap size of the tip were variables for different cooling configurations. from the results of this study, a significant cooling increasing was provided by the dirt purge holes. the injected coolant out from these holes affected the shroud and flooded the tips that resulted in reducing the leakage of the tip flow. chandrakant et al. [30] conducted a comparison study between the turbulator and using a helicoidally ducted blade for several geometrical proportions to estimate which is better on cooling. it was noted a significant enhancement for the characteristics of cooling of the turbine blade when using turbulator geometry of the larger ratio of the radial thickness of the turbulator to the helicoidally duct outer diameter (e/d). htwe et al. [31] gas turbines have an indispensable part in electric power generation. gas turbine innovation is utilized as a part of a ranking of arrangements for electric power epoch. the leading and trailing edge of the turbine rotor is the most critical segment in the gas turbine power plant. john et al. [32] designed and analyzed a gas turbine blade. catia and ansys were used for the design and the finite element analysis, respectively. life assessment and post processing were included in this work as well. ansys milieu facilities were used for the complex mesh generation and application of the working and boundary conditions. han et al. [33] turned the light on the techniques used for the blade cooling, such as rib-turbulated cooling, pin-fin cooling, and jetimpingement for two cases, rotating and fixed blades. priyanka singh et al. [34] used numerical analysis to study the heat transfer of gas turbines for six completely different models containing (5,9,13) in a single line row of passages and compared with another model that has (9,13) holes set in the 3 row. they developed a new model with 14 passages in the staggered arrangement. they found that the temperature gradient on the 13 passages was consistently distributed along the surfaces of the blade compared to 13 single line row. heat transfer increased in the arrangements of 13 and 14 staggered holes. allen and kofskey et al. [35] performed some visualization tests to see what these secondary flows looked like. additionally, they also studied the effect of ejecting flow from the turbine tips on the shape of the secondary flows. at the time of these tests, engine temperatures were not so high as to require cooling of the turbine blades for operation. the cooling of the turbine blade could be considered as a necessary aspect of engine design. the cooling method of the rotor blade of the turbine by air passing inside the hollow blades and taking out it from the tip of the blade can be considered one of the most practical ways of varying the pattern of the secondary flow. g. narendranath et al. [36] analyzed the 1st stage of the rotating gas turbine blade using ansys 9.0. the blade material used in the analysis is n155 alloy. the structural and thermal analyses were conducted numerically (fem). the temperature gradient from le to the te on the surface of the blade was ranged from 839.531 ˚c to 735.162 ˚c at the blade tip. it is noticed that the minimum thermal stress was 1450 which is less than the yield strength of the material and the maximum thermal fatigue was 1217. v.vijaya kumar et al. [37] investigated a specific power turbine design in order to maximize the turbojet engine. for an obvious awareness of the compound thermal and mechanical stresses for the centrifugal and axial mechanical forces. the circumferential rotor speed and stream velocities were preserved in the feasible range to reduce the losses. the base profiles are completed using the potential flow method taking into consideration all flow conditions during the analytical solution process. the last stage of the compressor provides the cooling air for the blade holes. the configurations of the interior cooling holes influence the amount of transferred heat rate and the distribution of the temperature at the interior of the blade; besides that, the cooling air mass flow rate will affect the total turbine efficiency. the trivial choice for holes or passages is a circular shape, and the coolant fluid enters the blade hub and then comes out from its tip or the trailing edge. in the modern design of blades, the flow inside the adjacent holes takes various orientations b.h. dennis et al [38]. dulikravich et al. [39, 40] applied these optimization algorithms for analyzing the aerothermal –elastic characteristics of the blade of the turbine. the channels were split using ribs and their thicknesses and locations were specified according to a genetic algorithm. a restriction in the research development scope is appeared by using this model. another study kennon et. al. [40] investigated the optimized number, location, and size of the circular channels that were placed near the surface of the blade. the number of channels was limited by using the upper and lower limits of the channel diameter for minimizing the total transferred heat. verstraete et al. [41, 42] optimized the position and size of the five channels having circular shapes in the 3d blade. maximizing the blade lifetime and limiting the flux of the cooling air mass are the main objectives of the study. namgoong et al. [43] utilized alternative models and experiment optimization design methods for reducing the loss in the pressure for the 3d u-bend duct having 4-edges. two edges were fixed, while the remaining two edges were permitted to change at 8-points within the channel. a recent study by nagaiah et al. [44] used the quadrilateral channel with an internal cooling system represented by the tabulating the ribs of channel walls. a semi-cylinder shape of ribs was adopted. the external flow on and close to the blade was not considered. a multiobjective optimization was adopted for increasing the convection coefficient of the transferred heat, the effective surface of heat transfer, and decreasing the loss in the pressure of the channel pressure. the main emphasis of the previous studies is on the predefined channels. this can remove from our research scope many optimal shapes. nowak et al. [45] optimized the maximum thermal gradient and temperature using the genetic algorithm method with four curves of bezier. some controlling points were constrained for decreasing the design variable numbers. this led to losing the smoothness control on the surface channel, in which many unsmooth corners and shapes were included. the results of the reviewed previous researches were summed up in table 1. akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 219 table 1. summary of results of significant literature studies. results method year author the second configuration provided better performance than the others. three different types of the arrangement of the film cooling 2004 yang et al [8] the temperature gradient from le to the te was ranged from 839oc to 735oc at the blade tip. the minimum thermal stress was 1450 n/mm2 which is less than the yield strength and the maximum thermal fatigue was 1217 n/mm2. analyzed the 1st stage of the rotating gas turbine blade using ansys 9.0 by used n155 alloy 6002 g. narendranath et.al [36] using (rans), coupled with the k-ε model has been appointed as an important norm design and the simulation analysis. using correlation equations with experimental data of nu number. 6002 choo et al [19] air flows from the holes (cold air) created a protective layer all around the surface of the airfoil and the end walls. lower temperature values were noticed on the entrance to the holes as well as the surfaces that were subjected to a high temperature hot gas. apply the cooling process of an air force film of a turbine van with 648 holes 2011 ni et al. [18] the decrease in the temperature values and the reduction in the temperature drop was motivated by the increasing number of the blade channels. used titaniumaluminum alloy properties and variant cases with different hole numbers of (7, 8, 9, 10, 11, and 12) 6022 b. deepanraj et.al [20] the blade with 13 holes is optimal and the thermal properties of inconel-718 material are better whereas induced stresses are lesser as compared to the chromium steel. discuss the four various models without and with channels that have different hole numbers (5, 9&13) with different materials, inconel718, and chromium steel. 6022 k hari brahmaiah et.al [14] blade with 10 № of holes is more stresses than the other models. lastly, the model with nine holes has produced the optimum solution. tested the stainless steel thermal and structural analysis. four variant cases containing of blade without and with different number of passages (7, 8, 9, and 10) 6022 reddy [21] increasing the flow rate of the mass was a good factor for increasing cooling effectiveness used for the numerical simulation and solving the governing differential equations 6022 kumar [13] the shape of the cooling channels and its location affected the heat transfer amount, temperature gradient inside the blades, temperature distribution, and cooling air-mass flux. using the reduced method of conjugate heat transfer 6022 b.h. dennis [17] a sensibility test on the jet impingement configuration and flow status was specified and was demonstrated to the internal cooling of the first stage bucket. numerical analysis of different heat transfer methods of jet impingement on a half-circular face. 6022 abdulla r. al ali et al [23] coolant steam is more efficient than the air when examined using the same conditions. comparison of coolant air and steam was carried out 6022 moskalenkoa et al [22] the location and the form of the last hole showed a significant role for all goal functions. the internal and external heat transfer was performed in a central scheme to find out the optimal function 6022 k. mazaheri et al [26] the coating thickness has a critical impact on the thermal and mechanical characteristics of the blade besides increasing the working period of the blade (blade life). studied the effects of varying the thickness of a thermal barrier coating (tbc) on the style of temperature distribution for a turbine blade 2017 a. ziaei-asl et al [27] 3. discussion of analysis results during the last decade, the studies of optimization were significantly advanced. the optimization algorithms are now used broadly especially in engineering applications due to the development in the computational hardware that used the numerical methods in solving the problems. the cooling system of the turbine blade is one of the applications that could be modeled and analysed using these algorithms. the result of titus.r et. al. [15] showed that increasing holes number with reducing its size and reducing the gap between them led to a good design. the existing design and the modified design (increasing the number of the holes) showed 1250k and 1191.6k, respectively. however, the serpentine design is cost effective and requires more effort because of the difficulties in the manufacturing processes compared to the other available designs. results of moskalenko et al. [22] showed the comparison of coolant air and steam was carried out, and the computations were done using ansys fluent tool. the coolant steam is more efficient than the air when examined using the same conditions as shown in fig. 3. 220 akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 figure 3. shows the result of a.b. moskalenkoa et al. [22]. results of h.d.a et. al. [24] showed that, for all materials used in the blade modeling, the nusselt number and the coefficient of the heat transfer were constant at the surfaces of the hole while the coefficient of the heat transfer was high at the entrance as shown in fig. 3. figure 4. shows the result of harsha d a et al. [24]. the results of ziaei-asl et. al. [27] temperature distribution, thermal stress, and thermal strain showed that the coating thickness has a critical impact on the thermal and mechanical characteristics of the blade besides increasing the working period of the blade (blade life) as shown in fig. 5. figure 5. average and maximum temperature vs. the tbc thickness [27]. the result of narendranath et. al. [36] noticed that the temperature gradient from le to the te on the surface of the blade was ranged from 839.531 oc to 735.162 oc at the blade tip. the minimum thermal stress was 1450 which is less than the yield strength of the material and the maximum thermal fatigue was 1217. and the results of hasanpour et. al. [28] showed that temperature distribution at the mid-span of the external surface of the blade was in a good agreement compared to the experimental data as shown in fig. 6. the maximum value of the temperature was noticed at the trailing edge of the van right at the very thin metal of the van. this value of the temperature was closer to the passage free stream temperature than that corresponding of the coolant, because of thermal resistance which was greater than the external conduction or convection resistance within the metal. figure 6. experimental and calculated data of [28]. akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 221 4. conclusions the usage of a cooling process in the gas turbine blade is essential. it may be an external or internal cooling according to the area of application. some of application like aviation engines require very high turbine inlet temperature and thus usage either external or internal is not sufficient and need to incorporate both of them. some applications need only internal cooling like in medium size gas turbine used in electric power plants. the interest in the development of internal cooling increased considerably in the last decade due to its efficient merits in minimizing hot spots that occurred due to high turbine inlet temperature. in addition, some researchers are interested to investigate the effect of adding ribs inside the serpentine passages of cooling holes and the optimum distribution of them. the selection of appropriate method is a matter of economic justification according to the area of application. the goal of previous studies aforementioned is to minimize the hot spots that may occur due to severe conditions and resulted in thermal stresses as stated in table 1. this goal is achieved via different approaches as stated in this comparison study and the great achievement belongs to narendranath et. al. [36] where the maximum temperature is lowered by 12% and thermal stress was lowered by .% 22 references [1] j.-c. han, s. dutta, s. ekkad, gas turbine heat transfer and cooling technology, crc press, 2012. [2] d. luckey, d. winstanley, g. hanus, m. l'ecuyer, stagnation region gas film cooling for turbine blade leading-edge applications, journal of aircraft, 14(5) (1977) 494-501. [3] a. mehendale, j. han, influence of high mainstream turbulence on leading edge film cooling heat transfer, (1992). [4] y. yao, j.-z. zhang, l.-p. wang, film cooling on a gas turbine blade suction side with converging slot-hole, international journal of thermal sciences, 65 (2013) 267-279. [5] p. martini, a. schulz, h.-j. bauer, film cooling effectiveness and heat transfer on the trailing edge cutback of gas turbine airfoils with various internal cooling designs, (2006). 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[28] a. hasanpour, m. farhadi, h. ashorynejad, hole configuration effect on turbine blade cooling, world academy of science, engineering and technology, 49(1) (2011) 240-244. [29] e.l. couch, measurements of cooling effectiveness along the tip of a turbine blade, virginia tech, 2003. [30] c.r. kini, s.b. shenoy, y.n. sharma, computational conjugate heat transfer analysis of hp stage turbine blade cooling: effect of turbulator geometry in helicoidal cooling duct, world academy of science, engineering and technology, 2012(70) (2012) 645-652. [31] h.h.w. win lai htwe, nyein aye san, ,, design and thermal analysis of gas turbine blade, international journal of mechanical and production engineering,, 3(7) (2015). [32] t.r. john.v, the design and analysis of gas turbine blade, international journal of advanced research and studies,, 2(1) (dec 2012). [33] j.-c. han, h.-c. chen, turbine blade internal cooling passages with rib turbulators, journal of propulsion and power, 22(2) (2006) 226-248. [34] p. singh, o. shukla, heat transfer analysis of gas turbine rotor blade through staggered holes using cfd. [35] h.w. allen, m.g. kofskey, visualization study of secondary flows in turbine rotor tip regions, (1955). [36] g. narendranath, s. suresh, thermal analysis of a gas turbine rotor blade by using ansys‟‟, international journal of engineering research and applications, 2(5) (2012) 2021-2027. [37] r.l.n. . vijaya kumar1, ch.srinivas3, design and analysis of gas turbine blade by potential flow approach, int. journal of engineering research and .application.www.ijera.com 4(1) (january-2014. ). [38] b.h. dennis, i.n. egorov, g.s. dulikravich, s. yoshimura, optimization of a large number of coolant passages located close to the surface of a turbine blade, in: asme turbo expo 2003, collocated with the 2003 international joint power generation conference, american society of mechanical engineers digital collection, 2003, pp. 13-19. [39] g.s. dulikravich, t.j. martin, z.-x. han, aero-thermal optimization of file:///d:/00%20mechanical%20department/00%20مجلة%20القادسية/رفع%20اعداد/اعداد%202020/العدد%20الثالث%20المجلد%2013/7%20اكرم%20+%20د%20نصير%20ok/www.ijera.com 222 akram luabi , naseer hamza /al-qadisiyah journal for engineering sciences 13 (2020) 215–222 internally cooled turbine blades, computational fluid dynamics'98, (1998) 158-161. [40] s. kennon, g. dulikravich, the inverse design of internally cooled turbine blades, (1985). [41] s. amaral, t. verstraete, r. van den braembussche, t. arts, design and optimization of the internal cooling channels of a high pressure turbine blade—part i: methodology, journal of turbomachinery, 132(2) (2010). [42] t. verstraete, s. amaral, r. van den braembussche, t. arts, design and optimization of the internal cooling channels of a high pressure turbine blade—part ii: optimization, journal of turbomachinery, 132(2) (2010). [43] h. namgoong, c. son, p. ireland, u-bend shaped turbine blade cooling passage optimization, in: 12th aiaa/issmo multidisciplinary analysis and optimization conference, 2008, pp. 5926. [44] n. nagaiah, multiobjective design optimization of gas turbine blade with emphasis on internal cooling, (2012). [45] g. nowak, w. wróblewski, i. nowak, convective cooling optimization of a blade for a supercritical steam turbine, international journal of heat and mass transfer, 55(17-18) (2012) 4511-4520. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٢٤ free vibration analysis of a symmetric and anti-symmetric laminated composite plates with a cutout at the center abstract the natural frequencies of composite laminates plate with effect of various plate parameters have been studied using ansys5.4 program. laminate composites are increasing used in various mechanical structures and industrial applications, due to their higher stiffness and higher strengthto-weight ratio. the effects of number of layers, angle of fiber orientation, boundary conditions, width to thickness ratio and laminate arrangement with the natural frequencies of plate having cutout at the center are studied. the non-dimensional fundamental frequency of vibration is found to increase with increase in width to thickness ratio and angle of fiber orientation. the natural frequencies of plate depend on size and shape of the cutout, with increasing values from the plate without cutout because the mass of the plate decrease. the effect of number of layers is found to be insignificant beyond four layers and the laminate arrangement show different results between symmetric and anti-symmetric laminate plate. some of the results compared with m.k.pandit et al. [2], that have various size of rectangular cutout at the center, with good agreement results. keywords: free vibration, laminate composite plate, symmetric, anti-symmetric, cutout. v���ا *b @'s ة ����د�w��� � c�ة وا�w���� اyه�jاز ا�%� �����ح ا���آ�5 ا��%g ��1ون n�b ��i!ع � ( ��( � :� ا�5�yر، 8�. ا���1�9 ا��� ا�<=>� v-���� g�ام ا��ة -�a+� ات �1���<���إن ا���,(�ح ansys 5.4.@�? درا��� ا���� ددات ا�(g+�+�� �'�,(�ح ا�� آs����1 ���gف @ �gآ ��ا �g,�� ^+�+�����'�& �1s�y و-��و-�� ��qk��4اc �+��#t��ت ا���+g)��+��6+6+�� وا��اء اo!) �8 -<�'| ا��م 671* وا�>�, ���ت ��8 ا����2n�@ ��@ o+ ا��a+� ات . إ�& ا��زن �)�&�'���? درا��� ��^ ا��� ددات ا�(g+�+�� �'�,(�ح ا���8 @����ي ��@ ?�@ y�m� @g+^ إن ا�� دد ا�(�g,� . 8��+g ا�� ض إ�& ا�,�y وآm�@ y e+@ ا��+�ف ، t وف ا���+(� ا�، زاو�� ا��+�ف ، ا����9'� �1�د ا�,(�ح 4 �? . ا�sا@ �ه 8�sه�oاز �oداد -�) ز���دة ��,�g ا��� ض إ��& ا��,�y و-�) ز���دة زاو��� ا��+��ف &�'� ������ 8��+g)�دد ا ���وان ا �ةو6u* ا� $ &�'���^ ا���y�'�@ c 8 ���2ب ا���!�دة -) ز��دة �8 ا�� ددات �',(�ح ا���8 @����ي . pgt�� ت���g)�د ا���ان @��2+ �^ ا�ر��g= (1ت وان @ @+e ا�vk���� 8)�� pk�$t -<�'$�� �'�,(�ح ا���#��� ة وا�a+� -�#��� ة x@ز��د ��ي �1 +f . ر�����?�@ (�'t��,��ا vk��#�0�1 اm.k.pandit et al. [2], ام� .وآ�� ا�#��vk -���ر�1 -,�(+'� ا�67* و4�1 �م -<�'$� ��2ب �1��< khaldoon f. brethee mech. engineering university of anbar al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٢٥ nomenclature u : flexural displacement (m). h : thickness of plate (m). e : young modulus (n/m 2 ). u(x,y) : mode shapes. m,n : mode numbers. m : bending moment (n.m). v : volume fraction. d : bending rigidity (n.m). ω : natural frequency (rad/sec). ώ : non-dimensional natural frequency. ρ : density (kg/m3). υ : possion ratio. α : angle of fiber orientation. introduction laminated plates and shells have been used in many engineering applications in recent years because of their many beneficial properties. researches are produced to design safe and more economic thick laminated composite materials through number of layers, fiber angles, laminated distribution,…etc. the one of the main practical consideration inevitable in structures are cutouts, which are used as access ports for mechanical and electrical systems, damage inspection, altering the resonant frequency of the structures and to serve as doors and windows. the undesirable vibrations may cause sudden failure due to resonance in the presence of cutouts. so to avoid the resonant behavior of the structures, the results of the free vibration analysis for the laminated composite structures using in the structural design are very important. also most structures whether they are used in civil, marine or aerospace are subjected to dynamic loads during their operation. therefore , free vibration and transient analysis of laminated composite plates and shells must be consideration. abdullah secgin and a.saide [1] study presents a detailed procedure for the implementation of a discrete singular convolution (dsc) approach to the free vibration analysis of composite plates based on classical laminated plate theory (clpt). the approach performs a numerical solution of differential equation of motion by using a grid discretization based on distribution theory and wave lets. the solution of dsc method give good agreement compared with the exact results of simply supported isotropic thin beams, fully simply supported one layer isotropic and specially orthotropic plates, and also some symmetrically laminated thin composite plates orientated to become specially orthotropic. and prediction for laminated composite plates with different boundary conditions and ply numbers. free vibration analysis of laminated composite rectangular plate was discussed in the work of m.k.pandit et al. [2] using finite element method. a ninenodded isoparametric plate-bending element has been used for the analysis of free undamped vibration of isotropic and fibre reinforced laminated composite plates. two types of an effective mass lumping scheme with rotary inertia has been recorded. numerical examples of isotropic and composite rectangular plates having different fiber orientations angles, thickness ratio and aspect ratio have been solved. vibration analysis of simply supported rectangular plates with unidirectionally, arbitrarily varying thickness is proposed by sang wook and sang-hyun [3]. the plate is divided into a number of regions with constant thickness and the close-form frequency function that yields the eigenvalues of the plate is extracted by considering the condition of continuity in displacement and shape between the regions and by considering the simply supported boundary condition of plate. s. latheswary [4] study the linear and non-linear free vibration analysis of laminated composite plates using a finite element model, based on third-order shear deformation theory. this study has been motivated by the lack of open literature on large amplitude dynamic analysis of al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٢٦ laminated plates based on higher-order shear deformation theory. the effect of various plate parameters on the linear and non-linear fundamental frequencies of vibration is brought out. s.s. akavci [5] examined buckling and free vibration analysis of simply supported symmetric and anti-symmetric cross-ply thick composite plates on elastic foundation using a new hyperbolic displacement model. in this new model, in plane displacements vary as a hyperbolic function across the plate thickness, so account for parabolic distributions of transverse shear stresses and satisfy zero shear stress condition at the top and bottom surfaces of plate. the closed form solutions are obtained by using navier technique, and then buckling loads and fundamental frequencies are found by solving the results of eignvalue problems. the solution of the free and forced vibration analysis of laminated composite plates and shells using a 9-node assumed strain shell element have been given by won-long lee and sung-cheon han [8]. the natural frequencies of isotropic laminates and the forced vibration analysis of laminated composite plates and shells subjected to arbitrary loading are investigated. the effect of damping on the forced vibration analysis is studied. in the literature, study of free vibration analysis of laminated composite plates is very important for damage inspection and altering the resonant frequency. in the present work, free vibration analysis of symmetric and anti-symmetric laminated composite plates with multi shapes of cutout at the centre produced using a well known computer program ansys 5.4. the effect of various plate parameters such as number of layers, thickness ratio, fiber orientation and boundary conditions have been considered. the results obtained in the form of natural frequencies with the various parameters. some of results compared with those available in the literature to show the accuracy of present analysis. problem formulation a square plate used with cutout at the center has a uniform structure and constant thickness, while the cross section is varied at the lines through the cutout. differential equation of harmonic bending vibration for laminated thin composite plate with natural frequency (ω) having side length (a and b), thickness (h), average mass density (ρ) and poisson ratio (υ) can be written in cartesian co-ordinates (x, y) in terms of flexural displacement (u) as follows [7]: 0)2( 2 2 4 4 22 4 4 4 = ∂ ∂ + ∂ ∂ + ∂∂ ∂ + ∂ ∂ t u h y u yx u x u d ρ (1) substituting tj eyxutyxu ω ),(),,( = (2) gives 0)2( 2 4 4 22 4 4 4 =− ∂ ∂ + ∂∂ ∂ + ∂ ∂ uh y u yx u x u d ωρ (3) for simply supported plate from all edges the boundary conditions are: al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٢٧ 0),,( 0),,0( 0),,( 0),,0( = = = = tyam tym tyau tyu xx xx 0),,( 0),0,( 0),,( 0),0,( = = = = tbxm txm tbxu txu yy yy (4) and for clamped plate from all edges, the boundary conditions are: 0),,( 0),,0( 0),,( 0),,0( = ∂ ∂ = ∂ ∂ = = tya x u ty x u tyau tyu 0),,( 0),0,( 0),,( 0),0,( = ∂ ∂ = ∂ ∂ = = tbx y u tx y u tbxu txu (5) assumed mode shapes to be: b yn a xm yxu ππ sinsin),( = (6) this satisfies the partial differential equation and the boundary conditions. so, the natural frequency of orthotropic simply supported plate is: h d b n a m mn ρ πω ])()[( 222 += (7) m, n = 1,2,3,… the constitutive relationship for a homogenous orthotropic lamina in a state of plane stress as shown in fig.(1-a)is [6]:                     =           xy yy xx xy yy xx q qq qq γ ε ε τ σ σ 33 2221 1211 00 0 0 (8) where al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٢٨ xy yxxy yyyx yxxy xxyx yxxy yy yxxy xx gq e q e q e q e q = − = − = − = − = 33 21 12 22 11 1 1 1 1 υυ υ υυ υ υυ υυ (9) because of requirement that 2112 qq = , it can obtain: yyxyxxyx ee υυ = (10) in terms of volume fractions where 1=+ mf vv , it can be seen that : fmfmf fmfmf mxy mmffxy fmfmf fmfmf myy mmffxx vgggg vgggg gg vv veeee veeee ee vevee )( ])([ )( ])([ −−+ −++ = += −−+ −++ = += υυυ (11) finite element modeling the ansys 5.4 finite element program [9] was used to study free vibration analysis of laminated plates with multi shapes of cutout. for this purpose, the key points were first created and then the segments were formed. the lines were combined to create an area. fine meshes of element type shell 99 with element size 0.01m as shown in figure (1). modal analysis with subspace method have been used to extract modes number with boundary conditions as simply supported or clamped plate. results and discussions in order to demonstrate the accuracy and applicability of the present simulation, laminated composite square plates have been analyzed and compared with the published results. a simply supported laminate composite plate with different size of cutout at the plate center have been studied to compared with pandit et al. [1] for the first six minimum frequencies. so, a square laminate plate (a*a), (0/90) and (a/h=100) with different size of cutout considered. the results have been compared for frequency parameter of hea /)/( 2 2 ρωλ = show good agreement results as shown in table(1). the first six mode shapes of for laminate composite plate (0/90) without cutout shown in figure (2), given by present study of a deformation in z-direction. then the simulation include different thickness ratio, fiber orientation angle, number of layers and boundary condition with multi shapes of cutout and for symmetric and anti-symmetric laminate composite plate. the al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٢٩ effect of these various parameters on the fundamental frequency of vibration is studied by considering square laminates of side (a=25cm) and having the following material properties: e1 =25*10 10 n/m 2 , e2 =1*10 10 n/m 2 , g12= g13 =0.5*10 10 n/m 2 , g23 =0.2*10 10 n/m 2 , υ12= υ23= υ13=0.25 and ρ=1*10 10 kg/m 3 . the results are expressed in non-dimensional form as: 2 2 eh a ρω ϖ = (12) 1effect of number of layers: the cross-ply and angle-ply laminates with symmetric and anti-symmetric arrangement of layers having width to thickness ratio (10 and 100) with multi shapes of cutout are analyzed to study the effect of number of layers on the fundamental frequency. the results for angle-ply laminates is shown in figure (3), as the number of layers increase the fundamental frequency increase. the presence of cutout give high natural frequency, different with cutout because of less mass of the plate. it is also seen for all shapes that for laminates with symmetric lay-up, there is a gradual increase in the value with increase in the number of layers. but for anti-symmetric lay-up, there is a sadden increase in the value of (ώ) from two layers to four layers and thereafter the increase is at a slow rate. the fundamental frequencies for symmetric lay-up have a low value from that of anti-symmetric laminates. 2effect of fiber orientation: four-layers symmetric (α/-α/-α/α) and anti-symmetric (α/-α/α/-α) laminates with angle of fiber orientation varying from (0 o to 45 o ) with (a/h=10 and 100) are analyzed having different shape of cutout. a change in fiber orientation angle from (0 o to 45 o ) leads to an increase in the fundamental frequency of vibration in the case of both thick (a/h=10) and thin (a/h=100) plates as shown in figure (4). the fundamental frequency of vibration for symmetric arrangement is less than that for anti-symmetric arrangement, the difference being more for higher values of (α). it can also seen that the fundamental frequency of vibration for rectangular, square and circular cutout is higher than for plate without cutout. 3effect of boundary conditions: the variation of non-dimensional fundamental frequency with a/h ratio for a simply supported and clamped edges are shown in figure (5), by analyzing four-layers plate with symmetric (0/90/90/0) and anti-symmetric (0/90/0/90) laminates. in case of simply-supported edges, there is a sudden increase in the non-dimensional fundamental frequency up to (a/h=20), beyond which frequency remain practically constant for both symmetric and anti-symmetric laminate plate with an increase between them. but for laminates with clamped edges, the values are high than first and goes on increasing with a/h ratio. anti-symmetric laminate arrangement has low value from symmetric arrangement for both edge supported. conclusions it is important to predict the natural frequencies of laminate composite plate with cutout at the center because cutouts are commonly used as access ports for mechanical and electrical systems. the undesirable vibrations may cause sudden failures due to resonance in the presence of cutouts. the present models lead to the following conclusions: 1. natural frequencies depend on size and shape of cutout. 2. natural frequency increase with increasing the cutout size because of less mass of the plate. 3. non-dimensional fundamental frequency of vibration is found to be increase with increasing width to thickness ratio and angle of fiber orientation. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٣٠ 4. the effect of number of layers is found to be insignificant beyond four layers. 5. the non-dimensional fundamental frequency for symmetric arrangement is less than for anti-symmetric arrangement as a number of layers and angle of fiber changed, on the converse with a/h changed. 6. a change in angle of fiber orientation from 0 to 45 leads to an increase in the fundamental frequency of vibration in both thick (a/h=10) and thin (a/h=100). 7. the variation of non-dimensional fundamental frequency increase as a/h increases, but the increase is small beyond a/h=20 (as a thick plate). 8. the edge conditions of the plate play an important role in the frequency of vibration of the system. 9. non-dimensional fundamental frequency of vibration of clamped plate is higher than for simply supported plate, and farther increasing beyond (a/h=20). references [1] abdullah secgin & a. saide sarigul "free vibration analysis of symmetrically laminated thin composite plates by using discrete singular convolution (dsc) approach: algorithm and verification" jour. of sound & vibr. 315,197-211, (2008). [2] m. k. pandit, s. haldar & m. mukhopadhyay "free vibration analysis of laminated composite rectangular plate using finite element method" jour. of reinforced plastic & composites 2007 ; 26 ; 69. [3] sang wook kang & sang-hyun kim "vibration analysis of simply supported rectangular plates with unidirectionally, arbitrarily varying thickness " jour. of sound & vibr. 312,551562, (2008). [4] s. latheswary, k. v. valsajian & y v k s rao "free vibration analysis of laminated plates using higher-order shear deformation theory" ie(i) jornal-as, (2004). [5] s. s. akavci "buckling and free vibration analysis of symmetric and antisymmetric laminated composite plates on an elastic foundation" jour.of reinf. plastic & composites, vol. 00, no. 00 (2007). [6] valery v. vasiliev & evgeny v. morozov "mechanics and analysis of composite materials" elsevier science ltd., (2001). [7] werner soedel "vibration of shells and plates" marcel dekker, inc. new york, (2005). [8] won-hong lee & sung-cheon han "free and forced vibration analysis of laminated composite plates and shells using a 9-node assumed strain shell element" comput. mech. 39: 41-58 (2006). [9] y. nakasone, s. yoshimoto & t. a. stolarski "engineering analysis with ansys software" butterworth-heinemann is an imprint of elsevier, (2006) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٣١ table (1): frequency parameter hea /)/( 2 2 ρωλ = of simply supported cross ply (0/90), square laminate plate having rectangular cutout. first six minimum frequencies cut-out size reference 1 2 3 4 5 6 0.2a*0.2a 0.4a*0.4a 0.6a*0.6a 0.4a*0.2a 0.8a*0.4a 0.6a*0.2a ref.[1] present study ref.[1] present study ref.[1] present study ref.[1] present study ref.[1] present study ref.[1] present study 9.071 25.057 25.057 37.643 53.154 59.856 9.11 25.63 25.80 38.11 54.23 60.64 9.061 19.93 19.93 35.07 42.866 60.27 9.12 20.25 20.34 35.67 44.76 61.81 11.085 18.173 18.173 31.56 33.92 51.712 11.31 18.69 18.71 32.87 34.34 53.11 8.765 20.57 24.35 36.57 50.83 60.81 8.85 21.31 27.82 37.12 51.22 62.14 9.603 11.542 27.03 30.63 49.42 59.27 9.72 11.81 27.36 31.15 50.63 60.37 8.49 15.27 25.08 34.02 50.24 59.21 8.54 15.87 25.45 34.87 51.26 60.13 (d) (b) (c ) figure (1): geometry and mesh of the models (a)laminate plate without cutout. (b)mesh with circular cutout (r =0.2a). (c)mesh with rectangular cutout (0.2a*0.2a). (d)mesh with square cutout (0.2a*0.2a) (a) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٣٢ first mode third mode second mode fourth mode fifth mode sixth mode figure (2): the first six mode of laminate composite plates (0/90) as solved in ansys program. figure (3): variation of fundamental frequency with number of layers for symmetric and antisymmetric laminated plate. (a) without cutout. (b) with circular cutout. (c) with square cutout. (d) with rectangular cutout (a) 11 13 15 17 19 21 23 25 2 3 4 6 8 number of layers ώ symmetric (a/h=10) symmetric (a/h=100) anti-symmetric (a/h=10) anti-symmetric (a/h=100) 11 13 15 17 19 21 23 25 2 3 4 6 8 number of layers ώ symmetric (a/h=10) symmetric (a/h=100) anti-symmetric (a/h=10) anti-symmetric (a/h=100) (b) (c) 11 13 15 17 19 21 23 25 2 3 4 6 8 number of layers ώ symmetric (a/h=10) symmetric (a/h=100) anti-symmetric (a/h=10) anti-symmetric (a/h=100) (d) 11 13 15 17 19 21 23 25 2 3 4 6 8 number of layers ώ symmetric (a/h=10) symmetric (a/h=100) anti-symmetric (a/h=10) anti-symmetric (a/h=100) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٣٣ figure (4): variation of fundamental frequency with fiber orientation angle for four layers symmetric (α/-α/-α/α) and anti-symmetric (α/-α/α/-α) laminated plate. (a) without cutout. (b) with circular cutout. (c) with square cutout. (d) with rectangular cutout (a) 12 14 16 18 20 22 24 26 28 0 15 30 45 angle of fibre orie ntation ώ symmetry 4-layers (a/h=10) symmetry 4-layers (a/h=100) anti-symmetry 4-layers (a/h=10) anti-symmetry 4-layers (a/h=100) (b) 12 14 16 18 20 22 24 26 28 0 15 30 45 angle of fibre orie ntation ώ symmetry 4-layers (a/h=10) symmetry 4-layers (a/h=100) anti-symmetry 4-layers (a/h=10) anti-symmetry 4-layers (a/h=100) (c) 12 14 16 18 20 22 24 26 28 0 15 30 45 angle of fibre orientation ώ symmetry 4-layers (a/h=10) symmetry 4-layers (a/h=100) anti-symmetry 4-layers (a/h=10) anti-symmetry 4-layers (a/h=100) (d) 12 14 16 18 20 22 24 26 28 0 15 30 45 angle of fibre orientation ώ symmetry 4-layers (a/h=10) symmetry 4-layers (a/h=100) anti-symmetry 4-layers (a/h=10) anti-symmetry 4-layers (a/h=100) (a) 13 17 21 25 29 33 37 41 10 30 50 70 90 a/h ώ symmetric simply supported symmetric clamped anti-symmetric simply supported anti-symmetric clamped (b) 13 17 21 25 29 33 37 41 10 30 50 70 90 a/h ώ symmetric simply supported symmetric clamped anti-symmetric simply supported anti-symmetric clamped al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٣٣٤ figure (5): variation of fundamental frequency with edge condition for four layers symmetric and anti-symmetric laminated plate. (a) without cutout. (b) with circular cutout. (c) with square cutout. (d) with rectangular cutout (c) 13 17 21 25 29 33 37 41 10 30 50 70 90 a/h ώ symmetric simply supported symmetric clamped anti-symmetric simply supported anti-symmetric clamped (d) 13 17 21 25 29 33 37 41 10 30 50 70 90 a/h ώ symmetric simply supported symmetric clamped anti-symmetric simply supported anti-symmetric clamped article al-qadisiyah journal for engineering sciences 13 (2020) 314–320 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mujtaba_abdulkadhim@mustaqbal-college.edu.iq (mujtaba a. flayyih) https://doi.org/10.30772/qjes.v13i4.724 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. design of hydraulic exciter using nonstandard backstepping with integral sliding mode mujtaba a. flayyih a , mohsin n. hamzah b , jafar m. hassan c a al-mustaqbal university college, hillah, iraq. b university of technology, baghdad, iraq. c al-turath university college, baghdad, iraq. a r t i c l e i n f o article history: received 10 november 2020 received in revised form 31 december 2020 accepted 31 december 2020 keywords: hydraulic simulator, quarter car, suspension system, sliding mode control. a b s t r a c t the hydraulic system plays an important role in the design of many mechanical devices due to its high power to weight ratio. in this work, a theoretical study of a hydraulic stimulator was performed to conduct suspension tests in a quarter car in the laboratory. due to high nonlinearity in the hydraulic systems, a robust controller based upon integral sliding mode (ismc) with nonstandard backstepping was used to perform the tracking process of the hydraulic actuator to the required road profiles. the controller design divided into two parts: the first part deals with the generation of the ideal control force which satisfied all the tracking requirements by using ismc. the second part of the controller is the replacing of the ideal control force with the actual hydraulic force with all parameters by using nonstandard backstepping control. the effectiveness of the exciter control system was performed by using two road profiles i.e. bump road profile and random road profile. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction active vibration control is one of the most advanced technologies to improve functionality and safety of mechanical structures [1], [2]. hydraulic systems have been widely used in a large number of fields applications to perform the activity of these vibration systems due to their small size to power ratios and their ability to apply very large force and torque. hydraulic systems play an important role in transportation, earth moving equipment, aircraft and industry machinery with heavy duty applications [3], [4] . the hydraulic system is highly nonlinear system due to different parameters such pressure flow characteristic, variations of control volumes and associated stiffness, etc. merritt [5]. from the control point of view, the hydraulic actuator have two main functions: the first one is the force tracking control niksefat et al. [6] and the second one was the position control ali et al. [7]. in this work, the hydraulic system designed as an exciter for testing the quarter car suspension system model in the laboratory i.e. for generation road profiles for the system. therefore, the literature focused on the positioning control of the hydraulic system . there are many researches used the linearized dynamic equation of the hydraulic servo-system such as eong l. et al. [8], dean h. et al. [9] and others. this linear system is not suitable to give real results when applying control methods because of physical of the hydraulic system which is highly nonlinear. another trends of studies used linear control methods such as g. p. liu et al. [10], bobrow et al. [11] etc. g. p. liu et al. [10] performed analytical and experimental study for two hydraulic actuators to track the position of the system by using an http://qu.edu.iq/ mailto:mujtaba_abdulkadhim@mustaqbal-college.edu.iq https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ https://en.wikipedia.org/wiki/hillah https://en.wikipedia.org/wiki/iraq javascript:; javascript:; mujtaba a. flayyih , mohsin n. hamzah , jafar m. hassan /al-qadisiyah journal for engineering sciences 13 (2020) 314–320 315 optimal-tuning nonlinear pid control strategy of two hydraulic actuators to track the position of the system. in the same context, bobrow et al. [11] adopted the optimal linear quadratic control to solve the problem of a servo single rod hydraulic cylinder system. these linear control methods such as pid controller, pole placement, optimal controls etc. which are not sensitive for disturbances and nonlinearities of the hydraulic system. on the other hand, xiuping yuan et al.[12] performed an analytical study of the single rod hydraulic actuator and made certain the structure of the fuzzy controller, input or output variable, the quantitative variable, the proportional variable and fuzzy reasoning theorem based on the manipulative experiment. backstepping control method is one of the robust control methods and used by many researchers such as prut nakkarat et al. [13] and others. they employed an experimental and theoretical study of the electrohydraulic actuator. the researchers derived directly the dynamic equation based upon force variables instead of position variables. they used proportional integral observer to estimate the force rate and pressure. sliding mode controller is the one of the well algorithms used in hydraulic systems since it has its outstanding characteristics in compensating for the nonlinearities and disturbances of electromechanical systems, therefore many of researchers applied these methods on electrohydraulic systems, for example y liu et al. [14], kai guo et al. [15] and others. y liu et al. [14] designed a standard sliding mode controller for the electrohydulic system connected to the flexible load, i.e. spring and mass. they introduced first-order weighted error function as sliding surface. the experimental results presented the effectiveness of the position control of this system. while, kai guo et al. [15] performed a theoretical and experimental study for force tracking of the electrohydraulic actuator. they used cascade controller based on an extended disturbance observer to track desired position trajectory for electro-hydraulic single-rod actuators in the presence of both external disturbances and parameter uncertainties. the researchers used sliding mode controller to compensate the disturbance estimation error estimated. in the same context, they used the backstepping techniques with lapenove stability for tracking the actuator pressure. they presented that the proposed controller gives excellent tracking performance in the presence of the disturbances and nonlinearities. the main objective of the present work is to design and implement an ismc with non-standard backstepping for the exciter system with hydraulic actuator. the first step in this controller is to design an ideal control force to perform the required single using ismc. the current ismc is an update to the conventional sliding mode, on which the reaching phase was eliminated by initiating the system state at sliding surface, therefore, the robustness is per formed from the first instant. the feature of the ismc is that it keeps the order of the system where the uncertainties and perturbations rejected from the system model and make the system as an ideal model with known nominal parameters. in addition, ismc can also be used as a perturbation’s estimator, which solves one of the main drawbacks of the sliding mode control, which is the chattering problem utkin et al. [16]. the second step is the inclusion of the nonlinear singlerod hydraulic actuator as controller force by using the nonstandard backstepping which based on the sliding mode control to perform stability. also, the observer sliding mode control was used as a differentiator of the ideal control force in the backstepping step due to the nonlinearities and the uncertainties appears in the derivative of the ideal control force. 2. mathmatical modelling mathematical model is defined as a set of equations which describe the dynamic characteristic of the system there are differed way to represent the model depending on the application of the system and circumstances, one mathematical model may be better suited than the other models for specific. the exciter model system used in this paper consists of mass (m) which tracked the required path generated by the actuator, fig. (1). therefore, the mathematic model presented as: 𝑚�̈� = 𝑢 − 𝑚𝑔 − 𝑐�̇� (1) where 𝑧 is the displacement of the mass and u is the ideal control force, g is the acceleration of gravity and c is the damping coefficient of the actuator. figure 1. schematic of the model the force which be used to generate path of the system is produced by hydraulic actuator. therefore, it is necessary to explain the dynamics equation of the actuator and servo valve, firstly the actuator dynamics equation is: 𝐹ℎ = 𝑃1 𝐴1 + 𝑃2𝐴2 (2) where 𝐹ℎis the actuator hydraulic force, 𝑃1 is pressure at the chamber (1) of the cylinder, 𝑃2is pressure at the second chamber of the cylinder, 𝐴1 is the cross sectional area of the chamber (1) while 𝐴2 the cross sectional area of the chamber (2). the derivation of p1 & p2 will be started from the continuity equation through the cylinder which be written as in [5], [17] 𝑉1 𝛽 𝑃1̇ = −𝐴(�̇�) + 𝑄1 − 𝑄𝐿1 − 𝑄𝐿𝐸1 𝑉2 𝛽 𝑃2̇ = 𝐴(�̇�) − 𝑄2 + 𝑄𝐿1 − 𝑄𝐿𝐸2 (3) where 𝑉1 = 𝑉𝑂1 + 𝐴 𝑧 , 𝑉2 = 𝑉𝑂2 + 𝐴 𝑧 are the total volume of the chambers, 𝑉𝑂1 and 𝑉𝑂2 are the extended and retract chamber volumes when (𝑧) equal to zero, 𝛽 is the effective bulk modules of the hydraulic oil, 𝑄𝐿1is the internal flow leakage of the cylinder, 𝑄𝐿𝐸1 and 𝑄𝐿𝐸2 are the external flow leakage of the chambers, 𝑄1 is the supply flow rate to the forward chambers and 𝑄2 is the return flow rate from the return chamber. the forward and return flow rates can be described as [7]: 𝑄1 = 𝑘𝑣 𝑥𝑣{𝑠𝑔 (𝑥𝑣)(𝑃𝑆 − 𝑃1) + 𝑠𝑔 (− 𝑥𝑣)(𝑃1 − 𝑃𝑡 )} 𝑄2 = 𝑘𝑣 𝑥𝑣{𝑠𝑔 (𝑥𝑣)(𝑃2 − 𝑃𝑎 ) + 𝑠𝑔 (− 𝑥𝑣)(𝑃𝑠 − 𝑃2)} (4) define function 316 mujtaba a. flayyih , mohsin n. hamzah , jafar m. hassan /al-qadisiyah journal for engineering sciences 13 (2020) 314–320 𝑆𝑔(∗) = { 1 𝑖𝑓 ∗ ≥ 0 0 𝑖𝑓 ∗ < 0 (5) where 𝑘𝑣 is the servo valve flow coefficient, 𝑥𝑣 is the displacement of the servo valve, 𝑃𝑆 is the supply pressure and 𝑃𝑡 is the pressure of the tank. practically while the hydraulic actuator is running, the servo valve displacement 𝑥𝑣 can be handled using the input voltage 𝑢ℎ that corresponds to the different required forces. the servo valve dynamic equation can be approximate as fialho et al. [18] 𝑥�̇� = 1 𝜏 (−𝑥𝑣 + 𝑢ℎ) (6) where 𝜏 is the time constant of the servo-valve. it is being showed that the dynamic of the servo-valve is much faster than the actuator dynamic when the time constant value is very small. thus, the equation (5) can be simplified as an algebraic equation −𝑥𝑣 + 𝑢ℎ = 0 deshpande et al. [19]. therefore, the equation (3) can be rewritten as: 𝑄1 = 𝑢ℎ 𝐻1 𝑄2 = 𝑢ℎ 𝐻2 (7) 𝐻1 = 𝑘𝑣 {𝑠𝑔(𝑢ℎ)(𝑃𝑆 − 𝑃1 ) + 𝑠𝑔 (− 𝑢ℎ)(𝑃1 − 𝑃𝑡 )} and 𝐻2 = 𝑘𝑣 {𝑠𝑔 (𝑢ℎ)(𝑃2 − 𝑃𝑎) + 𝑠𝑔 (− 𝑢ℎ)(𝑃𝑠 − 𝑃2)}. the hydraulic force of the actuator simplified as: 𝐹ℎ̇ = 𝑃1 ̇ 𝐴1 − 𝑃2 ̇ 𝐴2 𝐹ℎ̇ = 𝛽 𝑉1 (−𝐴1(�̇�) + 𝑢ℎ 𝐻1) 𝐴1 − 𝛽 𝑉2 (𝐴2 (�̇�) − 𝑢ℎ 𝐻1) 𝐴2 𝐹ℎ̇ = −(�̇�) { 𝛽 𝐴1 2 𝑉1 + 𝛽 𝐴2 2 𝑉2 } + 𝑢ℎ { 𝛽 𝐻1 𝐴1 𝑉1 + 𝛽 𝐻2 𝐴2 𝑉2 } (8) the states variable of the dynamic system are written as: 𝑥1̇= 𝑧 �̇�2 = ( 𝑎1 𝑥3 − 𝑔 + 𝑎1 𝑥2) �̇�3 = −(𝑥2) 𝑎3 + 𝑢ℎ𝑎4 (9) where 𝑎1 = 1 𝑚 , 𝑎2 = 𝑐 𝑚 , 𝑎3 = { 𝛽 𝐴1 2 𝑉1 + 𝛽 𝐴2 2 𝑉2 } and 𝑎4 = { 𝛽 𝐻1 𝐴1 𝑉1 + 𝛽 𝐻2 𝐴2 𝑉2 } where 𝑥1, 𝑥2 represents the displacements and velocity of the moving mass and 𝑥3 represents the dynamic equation of the pressure difference of the single rod hydraulic actuator. 3. controller design 3.1. ismc of the ideal control force the main objective of the control system in this work is tracking process i.e. the mass follows of the required path which is supplied to control system as an input signal. therefore, the first step in the control design is to drive an error function between the required path and the input required signal as follows: 𝑒(𝑡) = 𝑥1 − 𝑥𝑟 (10) where the 𝑥1 required displacement and the 𝑥𝑟 is the ideal signal supplied to the system. now let the state variables of the equation (12) as: 𝑒(𝑡) = 𝑥1 − 𝑥𝑟 = 𝑒1 (𝑡) 𝑒1̇(𝑡) = 𝑥1̇ − �̇�𝑟 = 𝑒2(𝑡) �̇�2(𝑡) = �̇�2 − �̈�𝑟 (11) therefore, the equation (13) presents as: 𝑒1̇(𝑡) = 𝑥2 − �̇�𝑟 �̇�2(𝑡) = ( 𝑎1 𝑢 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 (12) the electrohydraulic system includes several types of uncertainties and perturbations arise from variations of the system parameters such as variation of mass dynamics and the variations of hydraulic system, therefore the dynamic system of the electrohydraulic is rewritten as: 𝑒1̇(𝑡) = 𝑥2 − �̇�𝑟 �̇�2(𝑡) = ( 𝑎1 𝑢 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 + 𝑑(𝑒, 𝑡) + ∆𝑎1 𝑢 + ∆𝑎2 𝑥2 (13) where 𝑒𝑖 , ( 𝑖 = 1 𝑡𝑜 ) ∈ 𝑅 2 , 𝑎1 ∈ 𝑅 1 , 𝑢 ∈ 𝑅, 𝑑(𝑒, 𝑡) ∈ 𝑅 , 𝑑(𝑒, 𝑡) unmodeled dynamics and the nonsmoothed nonlinearities in the system and ∆𝑎1 𝑢, 𝑎𝑛𝑑 ∆𝑎2 𝑥2 represents uncertain parameters of the system dynamic. in the same context, let the design control law is: 𝑢 = 𝑢𝑛 + 𝑢𝑠 (16) where the 𝑢𝑛 𝑎𝑛𝑑 𝑢𝑠 represented the nominal and discontinuous controls of the system respectively. the nominal control used to stabilize the nominal system dynamics with the desired characteristics such as the dynamics of the nominal system become as: 𝑒1̇(𝑡) = 𝑥2 − �̇�𝑟 �̇�2(𝑡) = ( 𝑎1 𝑢𝑛 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 (14) while the discontinuous control 𝑢𝑠 worked to rejected the perturbation terms and the nonlinearities of the dynamic system in equation (15). after that, the design of the integral sliding mode and the perturbation terms can be formulating as follows: 𝑒1̇(𝑡) = 𝑥2 − �̇�𝑟 �̇�2(𝑡) = ( 𝑎1 𝑢𝑛 + 𝑎1 𝑢𝑛 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 + 𝛿(𝑒, 𝑢) (15) where 𝛿(𝑒, 𝑢) = 𝑑(𝑒, 𝑡) + ∆𝑎1 𝑢 + ∆𝑎2 𝑥2 is the perturbation term and represented the parameters variations, unmodeled dynamics, nonsmooth nonlinearities and external disturbances and it assumed to be obtain matching condition of the dynamic system kim et al. [20]. 𝛿(𝑒, 𝑢) = 𝑎3 �̂�(𝑒, 𝑢) (16) the design procedure of the ismc begins with the definition of the sliding variable𝑠(𝑥): 𝑠(𝑥) = 𝑠𝑜(𝑒) + 𝑧 (17) where 𝑠(𝑒), 𝑠𝑜 (𝑒) 𝑎𝑛𝑑 𝑧 ∈ 𝑅 1. in the same context, the sliding variable contains two parts. the first one 𝑠𝑜 (𝑒) will be designed similar to the conventional sliding mode i.e. as a linear combination of the system states. the term of the 𝑧 represented the integral term and determined as below. from the sliding mode control theory [20], the derivation from the switching surfaces 𝑠 and its time derivative should be having an opposite sign in the nearby area of the switching surface 𝑠 = 0, i.e. lim 𝑠→0 +�̇� < 0 𝑎𝑛𝑑 lim 𝑠→0 −�̇� < 0 or s �̇� < 0 (18) elimination of the reaching phase which is distinguishing property of the ismc achieved by choosing the initial condition 𝑧 same that the initial condition of the sliding mode control 𝑠 which is zero. this mean that the dynamic of the system is in sliding surface from first instantaneity by selecting 𝑧(0) = −𝑠𝑜 (0). in this design the 𝑠𝑜 (𝑒) is equal to the state variable 𝑒2, therefore, �̇� is differentiated as below: �̇� = 𝑒2̇ + �̇� = ( 𝑎1 𝑢𝑠 + 𝑎1 𝑢𝑛 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 + (19) mujtaba a. flayyih , mohsin n. hamzah , jafar m. hassan /al-qadisiyah journal for engineering sciences 13 (2020) 314–320 317 𝛿(𝑒, 𝑢) + �̇� the integral term will be chosen similar to the derivative of the ismc in [1] i.e. �̇� = ( 𝑎1 𝑢𝑛 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 (20) thus �̇� becomes: �̇� = 𝑎1 𝑢𝑠 + 𝛿(𝑒, 𝑢) (21) and accordingly, the sliding condition becomes: 𝑠 ̇𝑠 = 𝑠 (𝑎1 𝑢𝑠 + 𝛿(𝑒, 𝑢)) (22) by selecting the conventional sliding mode control 𝑢𝑠 = −𝜌(𝑥) 𝑠𝑖𝑔𝑛(𝑠) (23) then the equation (24) becomes: 𝑠 ̇𝑠 = 𝑠 (𝑎1 (−𝜌(𝑒) 𝑠𝑖𝑔𝑛(𝑠)) + 𝛿(𝑒, 𝑢)) since s*𝑠𝑖𝑔𝑛(𝑠)=|𝑠| then 𝑠 ̇𝑠 = − 𝑎1 𝜌(𝑒) |𝑠| + 𝑠 𝛿(𝑒, 𝑢)) 𝑠 ̇𝑠 ≤ − 𝑎1 𝜌(𝑒) |𝑠| + |𝑠| |𝛿(𝑒, 𝑢)| 𝑠 ̇𝑠 ≤ |𝑠| {− 𝑎1 𝜌(𝑒) + |𝛿(𝑒, 𝑢)|} 𝑠 ̇𝑠 ≤ −|𝑠| {𝑎1 𝜌(𝑒) − |𝛿(𝑒, 𝑢)|} 𝑠 ̇𝑠 ≤ −𝑎1 |𝑠| { 𝜌(𝑒) − |𝛿(𝑒, 𝑢)| 𝑎1 } (24) it was assumed that 𝑎1 > 0 . the discontinue gain 𝜌(𝑥) that will perform the inequality in the equation (27) to ensure the right-hand side of this equation to be negative value i.e.: 𝜌𝑜 (𝑥) > | 𝛿(𝑥, 𝑢)| 𝑔2 or 𝜌𝑜 (𝑥) = 𝑘𝑜 + | 𝛿(𝑥,𝑢)| 𝑎4 , where the 𝑘𝑜 > 0 (25) by referring to the equation (24), the discontinuity in the right-hand side due to the 𝑢𝑠 will needed the finite time t to reach to the origin and then the system dynamic become in the sliding motion. based on the the dynamic system will be achieved by using the equivalent control which performed as follows: when 𝑠(𝑡) = 0, ∀ 𝑡 ≤ 𝑇, [21]also the �̇�(𝑡) = 0 and with 𝛿(𝑥, 𝑢) satisfied the matching condition in equation (19), the equivalent control can be calculated from the equation (24) as shown: 0 = 𝑢𝑠 + 𝛿(𝑥, 𝑢) ⇒ [𝑏 𝑢𝑠 ]𝑒𝑞= 𝛿(𝑥, 𝑢) (26) by substituting the equivalent control of the equation (29) in to the control law of the ismc with perturbations i.e. equation (18), the system is reduced to the nominal form as in equation (17) with the dimension equal to n. for this reason, the ismc is considered as full order sliding mode control because of the dimension of equations (15) & (17) are equal. since the remaining system is only the nominal system as in equation (10) the next step in the design of this control method is the determination of the nominal part of the system: 𝑒1̇(𝑡) = 𝑥2 − �̇�𝑟 �̇�2(𝑡) = ( 𝑎1 𝑢𝑛 − 𝑔 + 𝑎2 𝑥2) − �̈�𝑟 (27) therefore, the control design of the nominal system is: 𝑢𝑛 = 1 𝑎1 (−𝑛1𝑒1 − 𝑛2 𝑒2 + 𝑔 + 𝑎2 𝑥2 − �̈�𝑟 ) (28) as the result the nominal system dynamic is: 𝑒2̇ = −𝑛1𝑒1 − 𝑛2 𝑒2 , (29) where 𝑛1 & 𝑛2 are assigned based on the required system characteristic. 3.2. backstepping of the hydraulic force backstepping control is a well method to the control problems nonlinear systems such as active suspension system. a virtual control assumed to follow the intermediate variable, which performed to achieve the objectives of the control design. the hydraulic actuator force 𝐹ℎ considered virtual control force to track the ideal control 𝑢 that designed by ismc to perform the position tracking of the mass by the electrohydraulic system. the error between the virtual variable 𝐹ℎ and the active control element 𝑢 will be approach gradually to zero, thus: 𝑒𝑒(𝑡) = 𝐹ℎ − 𝑢 (30) where 𝑒𝑒(𝑡) is the error function between the ideal and virtual function. to derive the control law that will make the value s(𝑡) goes to zero, a nonstandard backstepping [22] is utilized here. first we have needed to derive the error function dynamics error function by differentiating equation (32) 𝑒�̇�(𝑡) = 𝐹ℎ̇ − �̇� = �̇�3 − �̇� = −(𝑥2) 𝑎3 + 𝑢ℎ𝑎4 − �̇� (31) the hydraulic system has many unmodelled parameters, no smoothed nonlinearities and uncertain parameters, therefore the equation (34) is rewritten as: 𝑒�̇�(𝑡) = −(𝑥2) 𝑎3 + 𝑢ℎ𝑎4 − �̇� + 𝑑(𝑥, 𝑡) (32) where 𝑑(𝑥, 𝑡) unmodeled dynamics the nonsmoothed nonlinearities system and represents uncertain parameters of the system dynamic. let the design control law is: 𝑢ℎ = 𝑢ℎ 𝑛 + 𝑢ℎ 𝑑 (33) where the 𝑢ℎ 𝑛 𝑎𝑛𝑑 𝑢ℎ 𝑑 represented the nominal and discontinuous controls of the system respectively. the nominal control used to stabilize the nominal system dynamics with the desired characteristics such as the dynamics of the nominal system becomes as: 𝑒�̇�(𝑡) = −(𝑥2) 𝑎3 + 𝑢ℎ 𝑛𝑎4 − �̇� (34) in the other hand, the discontinuous part used to reject the uncertainties in the system model i.e. the discontinuous control is performed as: �̇�(𝑡) = 𝑢ℎ 𝑑 𝑎4 + 𝑑(𝑥, 𝑡) (35) let the 𝑢ℎ 𝑑 = −𝜌𝑜 (𝑥) 𝑠𝑖𝑔𝑛(𝑒𝑒(𝑡)) 𝑒(𝑡) �̇�(𝑡) = 𝑒𝑒(𝑡) (−𝜌𝑜 𝑠𝑖𝑔𝑛(𝑒𝑒(𝑡)) 𝑎4 + 𝑑(𝑥, 𝑡)) = −𝜌𝑜 (𝑥)|𝑒𝑒(𝑡)| 𝑎4+ |𝑑(𝑥, 𝑡)| 𝑒𝑒(𝑡) ≤ −𝜌𝑜 (𝑥)|𝑒𝑒(𝑡)| 𝑎4+ |𝑑(𝑥, 𝑡)| |𝑒𝑒(𝑡)| ≤ |𝑒(𝑡) |𝑎4 {−𝜌𝑜 (𝑥) + |𝑑(𝑥,𝑡)| 𝑎4 } (36) it was assumed that 𝑔2 > 0 . the discontinue gain 𝜌𝑜 (𝑥) that will perform the inequality in the equation (19) to ensure the right-hand side of this equation to be negative value i.e.: 𝜌𝑜 (𝑥) > | 𝛿(𝑥, 𝑢)| 𝑔2 or 𝜌𝑜 (𝑥) = 𝑘𝑜 + | 𝛿(𝑥,𝑢)| 𝑎4 , where the 𝑘𝑜 > 0 (37) 3.3. state differentiator design 318 mujtaba a. flayyih , mohsin n. hamzah , jafar m. hassan /al-qadisiyah journal for engineering sciences 13 (2020) 314–320 in eq. (31), the proposed control law assumes ideal control force 𝑢 and its derivative are available. the first state u is available since it determined from the first step of the control design, i.e. ismc. the second state �̇� is the time derivative of u. hence, we need to obtain it using an observer. a robust sliding mode differentiator (smd) is proposed here to get �̇� by knowing u only. kokotović et al. [23] give the sliding mode differentiator; 𝜎 = 𝑢 − 𝜂 �̇� = 𝛼 ∗ 𝑡𝑎𝑛−1(𝛾 𝑢) 𝜏𝑣̇ + 𝑣 = 𝛼 ∗ 𝑡𝑎𝑛−1(𝛾 𝑢) } (38) where 𝜎 is the smd variable, 𝛼 and 𝜌 are differentiator parameters. the third equation in (39) 𝜏�̇� + 𝑣 = 𝛼 ∗ 𝑡𝑎𝑛−1(𝛾 𝑢) is a low pass filter (lpf) with time constant 𝜏, where the output of the lpf, 𝑣, is the estimated derivative 𝑢. according to deshpande et al. [19], the bound on the steady state estimation error is given by: |𝑣(𝑡) − �̇� | ≤ 2 𝜏 𝜌 𝑡𝑎𝑛 ( 𝜋 2𝛼 ℎ) (39) where ℎ = sup𝑡 |𝑢| 4. result and discussion as mentioned above, the hydraulic system exciter in this work used to simulate the road disturbances on the quarter car suspension system. therefore, two cases of road profiles studied to perform this purpose mishary [24] fig. (2): case 1: bump road profile the mathematical model of this profile is fig. (2 a), [18] 𝑥𝑟 = { 𝑑𝑜(1 − cos(𝜔𝑟 𝑡)), 𝑡 ≤ 1 0 , 𝑡 > 1 where 𝑑𝑜 represents the peak amplitude and 𝜔𝑟 a constant frequency in the disturbance model which depends on the car velocity and on the width of the disturbance on the road, which are set as. 𝑑𝑜 = 0.1 𝑚 and 𝜔𝑟 = 2𝜋 𝑟𝑎𝑑. case 2: random road profile the mathematical model of this profile is fig. (2 b), [19] 𝑥𝑟 = 0.05 cos(2𝜋𝑡) sin (0.06 𝜋 𝑡) table 1. the model parameters of the active suspension parameter value parameter value 𝑚 290 kg 𝑐 1000 n m/sec 𝑘𝑣 1e-9 𝛽 1.4e9 a 0.001311 𝑚2 𝑃𝑠 10342502 𝑁/𝑚 2 𝑉0 0.01311 𝑚 3 (a) (b) figure 2. the simulated road disturbance (m) fig. (2) presents the vertical displacement of the quarter car mass and the required profile for two cases. it shows the effectiveness of the proposed control method of the single rod hydraulic actuator to track the required profile with high accuracy. since the proposed control method in this work is divided into two steps, it is necessary to show the features of the ismc and nonstandard backsteeping to perform tracking process. for ismc, i.e. generation of the ideal control force, the sliding variable is the main parameter should be discussed. fig. (3) shows that the sliding variable (𝑠) equals to zero from the first instant i.e. 𝑠 = 0 for 𝑡 ≥ 0. this behavior of sliding surface (𝑠) which begins and continues with zero along simulations time presented the effectiveness of the of ismc over the conventional sliding mode control which reaches the stability over reaching phase not from the first instant. (a) (b) figure 2. vertical displacement of the hydraulic actuator vs required displacement mujtaba a. flayyih , mohsin n. hamzah , jafar m. hassan /al-qadisiyah journal for engineering sciences 13 (2020) 314–320 319 (a) (b) figure 3. sliding surfaces as mentioned in the mathematical modeling, the hydraulic model is added to the system by nonstandard backstepping with sliding mode. fig. (5) presented the ideal control force which was designed to satisfy the suspension system requirements with actual control force i.e. hydraulic force. this figure shows the high convergence between them over all simulation time which indicated the powerful of the nonstandard backstepping for the inclusion of the hydraulic force in the overall system model. the controller design ends with determination of the voltage which used as input to the servovalve. the servovalve adjusts the flow rate and pressure to the actuator chamber. fig. (6) shows the voltage curve of the two cases of the road profiles. (a) (b) figure 4. hydraulic force vs. ideal control force (a) (b) figure 5. input voltage of the hydraulic actuator 5. conclusions this work, represents a design of simulator for testing the quarter car active suspension system with generation different road profiles to simulate the actual road. the following conclusion have been drawn: the robust ismc gives better results in the design of virtual control force which performs all simulator requirements. the ismc performs the stability from the first instant which considered the main feature as compared with the conventional sliding mode control. the second step of the controller design which non-standard backstepping control has good convergence between the virtual control force and the actual hydraulic control force. 320 mujtaba a. flayyih , mohsin n. hamzah , jafar m. hassan /al-qadisiyah journal for engineering sciences 13 (2020) 314–320 references [1] j. liu, x. chen, j. gao, and x. zhang, “multiple-source multiple-harmonic active vibration control of variable section cylindrical structures: a numerical study,” mech. syst. signal process., vol. 81, pp. 461–474, 2016, doi: https://doi.org/10.1016/j.ymssp.2016.02.065. 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[25] v. s. deshpande, b. mohan, p. d. shendge, and s. b. phadke, “disturbance observer based sliding mode control of active suspension systems,” j. sound vib., vol. 333, no. 11, pp. 2281– 2296, 2014, doi: 10.1016/j.jsv.2014.01.023. article al-qadisiyah journal for engineering sciences 15 (2022) 238–240 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. corresponding author: eng.chem.20.post.14@qu.edu.iq https://doi.org/10.30772/qjes.v15i4.876 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. removal of methylene blue dye from simulated wastewater by cement kiln dust malak a. mashjel* and husham m al.tameemi department of chemical engineering, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 04 august 2022 received in revised form 20 october 2022 accepted 07 december 2022 keywords: adsorption organic dyes methylene blue simulation wastewater ckd a b s t r a c t the purpose of this work is to test and discover the efficiency of ckd from al-muthanna city, iraq. removing the methylene blue dye (mb) in simulated textile wastewater that was generated from the aldiwaniyah textile factory of diwaniyah city in iraq. the wastewater discharge from textile industries that contain methylene blue dye is removed by adsorption through cement kiln dust, therefore, was studied in this case. the best electrostatic action is the basic action between methylene blue and cement kiln dust. as cement kiln dust has especially nanostructure properties and the negative charge for his plane, the positive charge for methylene blue compound ability to simply adsorb above it. the optimum condition for gaining the best removal of dyes and reach to 99.57% is an initial concentration of 10 ppm, ph 9.0, temperature 30 c, dosage 1 gm, and rotary speed 150rpm. the reason for this may be due to the synergy effect of both the ph value of the media and the basic effect from the melting of the added adsorbent material in the media in addition to the presence of additional exchange sites when increasing the dose of adsorbent. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction pollution in the water is different shape in normal. pollution mainly forms from organic and inorganic materials. mostly, inorganic dirtiness is explained by the high mass of the substance like colour, whereas organic pollutants expand from molecules smaller like chloroform to a macrocyclic or heterocyclic substance like colour. dyes are cyclically organic compositions with a range of theist’s higher weights for molecules [1]. days are among the pollutants affecting the aquatic ecosystem being composed of a large group of harmful chemicals [2], [3]. what increases the environmental problem is that many industries, such as the textile industry, are depleting quantities of a large amount of water, as it is estimated the amount of water consumed to produce one kilogram of textiles is up to 200 litters and thus produces large amounts of wastewater contaminated with dyes different. in addition, organic days compounds its complex molecular structures and high molecular weight increase. it is difficult to treat sewage contaminated with dyes [4]. exposure to dyes in the textile industry it may cause major health problems to his health, ranging from simple effects to carcinogenic and mutagenic effects it was found that dyes can cause significant damage to the skin lungs and skin, causing headaches and nausea, as well as congenital malformations [5] added to because the dyes have effects on the kidneys, liver and bladder inflammation of the skin and asthma and cause problems in the nose and inflammation nose for people working in the textile industry after prolonged exposure [6]. 2. material and method some of the series are tested with different variables to know cement kiln dust efficiency. thus, basic methylene blue dye solutions (1000 ppm) were http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i4.876 http://creativecommons.org/licenses/by/4.0/ malak mashjel and husham al, tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 238–240 239 used (stock solutions) in the prepared laboratory by dissolving one gram from the required amount of dye in one liter from distilled water. experimental solutions were prepared required to dilute basic dye solutions with water distilled to give the required dye concentrations for experiments adsorption. table 1. material that used in experimental test materials purpose methylene blue to prepare a stock solution. hydrochloric acid 35-38% to treat ph value. sodium hydroxide to treat ph value. buffer solution to know the standard solution. table 2. equipment useful in experimental equipment description origin ph meter ph 211 romania stirrer model 1.613.01.001 germany cod test 0-1500 ppm --------- sensitive balance --------------------- air dryer -------------------- qualitative filter paper whatman no:42 -------- 3. adsorption experiment the adsorption experiments were carried out to study the effects of important measures: quantitative adsorbent material (cement kiln dust) and adsorbent concentration mb (methylene blue dye), ph value, temperature, contact time, and rotary per minute. specific amounts of dust have been added to cement kilns (adsorbent material) (0, 1, 2 g) in 250 ml beakers containing 100 ml of solutions of methylene blue dye (substance adsorbed) with different concentrations of dye (10, 55, and 100 mg/l) and ph values (3.0, 7.0 and 11.0), the temperature at (25, 35 and 45)c, contact time (1.0, 2.0 and 3.0 hr.) and rotary per minute (150, 250 and 350) rpm. the containers were placed in quantities of specific adsorbent material and different concentrations of the material adsorbents with different ph values on the stirrer at a limited stirrer speed, limited temperature, and limited contact time. after the stirrer operations are completed, they are collected to get samples ready. after the experimental run, the solution is tested in a cod meter. 4. results and discussion 4.1 effect of ph on the adsorption process the ph value plays an important role in the entire process of adsorption, especially on capacity adsorption due to its effect on providing concentrations of ions hydrogen + h and hydroxyl oh in which reaction system it appears from the results of jain and [7]. from (figure 1) the dyes removal (% r) increased from 67.46 % to 88.31 % when ph meter increased from 3.0 to 11.0 at the same condition for others variables. the low percentage of dye removal from its solutions water when using a ph value (3.1 conditions acidic) may be due to the abundance of hydrogen ions + h gained from hydrochloric acid used in adjusting the ph value of dye solutions water, which leads to competition between h + protons and cationic dye molecules (mb) on the exchange sites are available on the surfaces of the adsorbent and then electrostatic attraction between protons available in the form of large in the system and the surfaces of the adsorbent, accompanied by repulsion between the cationic dye molecules and the positive charges generated on the exchange surfaces, which causes a decrease in the rate of removing the dye in the system [8]. at the basic conditions at 11.0 the presence of an abundance of hydroxyl ions in the system (aqueous solution of dye and adsorbent) enables it to correlation with positive charges of methylene blue in its aqueous solutions, it can leave the medium to precipitate under basic conditions. figure 1. effect ph value and initial concentration on dye removal 4.2 effect of dye concentration on the adsorption process the initial concentration of the dye has an important role in the capacity of adsorption [9]. it is clear that dye adsorption increases in line with increasing ph value. it was observed from the results of the study an increase in the percentage of dye removal from its aqueous solutions at the same condition for other variables, the initial concentration of the dye provides an important driving force to overcome the resistance encountered the dye molecules as they move between the liquid phase and the solid phase [10]. from (figure 1) the dye removal (% r) increased from 89.02 % to 99.20 % when the initial concentration increased from 10 ppm to 100 ppm at the same condition for other variables. as it was observed at 1 g of the adsorbent material, the relative decrease in the percentage of removal of the dye when its concentrations increase in the system it may be caused by the saturation of the exchange sites of one gram of a substance adsorbing cationic dye molecules at the equilibrium time depends on the concentrations used [11], sites available adsorption is relatively high at the concentration low of the dye, which facilitates the connection of shipments dye at exchange sites, and at high dye concentrations the sites available for exchange are few and therefore the ions the dye takes longer to reach the exchange sites [12] allowing chance of repulsion between the charges of the dye molecules itself to remain in the solution away from the surfaces of the adsorbent material which explains the low percentage of removal. 4.3 effect of adsorbent dosage on the adsorption process from fig.2 the dye removal (% r) increased from 86.48 % to 92.11 % when the dosage increased from one gram to two grams at the same condition for other variables. the reason for the large increase despite the 240 malak mashjel and husham al, tameemi /al-qadisiyah journal for engineering sciences 15 (2022) 238–240 use of conditions acidic may be due to the use of an increased amount of dust base cement kilns that have a ph value of 12.4. and when soluble in aqueous solutions of the dye and with the help of stirrer operations (150, 250, and 350) provides hydroxyl ions negativity that may make the mean neutral tilted to the basal which provides suitable conditions for removing the dye from its aqueous solutions, add to this that increasing the amount of the substance adsorption means an increase in the surface area of sites adsorbents that increase the percentage of dye removal [13]. figure 2. effect dosage and temperature on dye removal figure 3. effect rotary speed and initial concentration on dye removal 4.4 effect of temperature on the adsorption process the temperature has an important effect on the adsorption process. as the temperature increases, the rate of diffusion of adsorbate molecules across the external boundary layer and interval pores of the adsorbent particles increase [14]. changing in temperature will change the equilibrium capacity of the adsorbent for adsorbates. from (figure 2) the dyes removal (% r) increased from 86.26 % to 89.52 % when the temperature increased from 25 c to 45 c at the same condition for others variables [14], [15]. 4.5 effect of rotary speed on the adsorption process in the present study, mixing and aeration were provided by the rotation of the discs. therefore, rotational speed was considered as an important parameter affecting the system performance. decolorization efficiency increased with increasing rotational speed [16]. from (figure 3) the dye removal (% r) increased from 87.48 % to 89.52 % when the temperature increased from 150 rpm to 350 rpm at the same condition for other variables [14], [15]. 5. conclusion in this study, the removal of methylene blue (mb) dye from aqueous solutions using adsorbents as cement kiln dust was investigated. optimization, parametric studies, adsorption isotherm, and kinetic studies were done. this work aimed to investigate the removal of methylene blue (mb) dye from an aqueous solution by eco-friendly approaches, and adsorption methods processes. reference [1] l. tinghul, t. matsuura, and s. sourirajan, 1983. effect of membrane materials and average pore sizes on reverse osmosis separation of dyes. ind. eng. chem. prod. res. dev., vol. 22, no. 1, pp. 77–85, doi: 10.1021/i300009a018. [2] n. fathy, 2006. removal of methylene blue by carbons derived from peach stones by h 3po 4 activation : batch and column studies. doi: 10.1016/j.dyepig..08.039. [3] s. d. khattri, 1998 . colour removal from aqueous solutions by adsorption. no. july, pp. 230–234,. [4] k. k. h. choy, j. f. porter, and g. mckay, 2000. langmuir isotherm models applied to the multicomponent sorption of acid dyes from effluent onto activated carbon. pp. 575–584,. [5] j. f. gonz and c. m. gonz, 2004. thermal regeneration of activated carbon saturated with p -nitrophenol. vol. 42, pp. 2285–2293, doi: 10.1016/j.carbon.2004.05.007. [6] w. j. ncz, 1987. the repeated exhaustion and chemical. vol. 21, no. 8, pp. 961–965,. [7] r. jain and m. shrivastava, 2008. adsorptive studies of hazardous dye tropaeoline 000 from an aqueous phase on to coconut-husk. vol. 158, pp. 549–556, doi: 10.1016/j.jhazmat..01.101. [8] v. vadivelan and k. v. kumar, 2005. equilibrium , kinetics , mechanism , and process design for the sorption of methylene blue onto rice husk. vol. 286, pp. 90– 100, 2005, doi: 10.1016/j.jcis..01.007. [9] s. wang, y. boyjoo, and a. choueib, 2005. a comparative study of dye removal using fly ash treated by different methods. vol. 60, pp. 1401–1407, doi: 10.1016/j.chemosphere.2005.01.091. [10] s. v. u. c. o. 2006. engineering and g. p. r. c. engineering, the removal of composite reactive dye from dyeing unit effluent. vol. 30, pp. 367–373,. [11] j. guthrie and a. unyayar. the removal of colour from textile wastewater using whole bacterial cells : a review. doi: 10.1016/s0143-7208(03)00064-0. [12] b. benaouda, l. duclaux, and l. duclaux. methylene blue and iodine adsorption onto an activated desert plant. doi: 10.1016/j.biortech.2008.02.053. [13] l. gong, w. sun, and l. kong, adsorption of methylene blue by naohmodified dead leaves of plane trees. vol. 2013, no. april, pp. 13–19, 2013, doi: 10.4236/cweee.2013.22b003. [14] p. pokethitiyook,. kinetics of basic dye ( methylene blue ) biosorption by giant duckweed ( spirodela polyrrhiza). doi: 10.1016/s0269-7491(03)00107-6. [15] t. shahwan and h. n. erten, 2002 . thermodynamic parameters of cs + sorption on natural clays. vol. 253, no. 1, pp. 115–120,. [16] flavio pavan, ana mazzocato, yoshitaka gushikem. removal of methylene blue dye from aqueous solutions by adsorption using yellow passion fruit peel as adsorbent, bioresoirce technology, 2008, v99-8, https://doi.org/10.1016/j.biortech.2007.05.067 https://doi.org/10.1016/j.biortech.2007.05.067 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� effect of flow-obstruction geometry on pressure drops in horizontal air-water two-phase flow hameed balassim mahood * hala a. kadim and ali n. salim university of missan – missan iraq : mail-e*com.yahoo@hbmahood abstract an analytical solution for local pressure drop due to obstructions in horizontal air-water twophase flow was presented. various obstruction shapes with size were investigated. an analysis based on the momentum conservation through obstruction region. the relationship between twophase multiplier and local (normalized) pressure drop with the gas superficial velocity were investigated. the results showed, a higher pressure drops pointed for larger obstructions. the present results was verified with experimental investigations. keywords: two-phase flow; pressure drop; obstructions; analytical solution; momentum conservation. �r �� ا���q ا�34)�2 ��7!ر�� ,�p ���� ا�m�� n�o�:!ن ا�3l!%� ا��eر �� اv�g!1u ا��6�u) "!ء وه�اء ( �:m�" (��! ��h-()�4 8���% 0��m n�� �1�� ��% 8�&�" ��"�1 :ا��>;� uru� �k��) .�]�� d( uب ا����� ا�� ��� d���ز ا��+ ا��� k)ر /0 اuا��� d# ن ا�?7 �kا� ���� dq ر�� a اء (دuء وه� �� ( دا a�@ ���أ �)� ر � �$� ا��08 . ��aا �����/ �� د . /0 ا��8 ر اu)اع ��4�n� �$ ��� ا��z+ وا��� 0k�u(ارض ��n ا��را�k /�0 ا ن ا�?7 #d ا��uر آ�ا�� ����a ا��uر ا�� زي �k�� .�]ا� dq ا����� x%/ ��� � ان ���ار ا������ d�q ا��[�. و � و9a.r � ر دة �0���k ا�) ر����� ��� رب ����� ا�����7 #l ا�)������� ا��uz���7رة . ����داد ����� ز����/ ����rو ���� و ���5��a لu%0 ا��������/ dا����� l# . uر(���y ا�����7 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� nomenclature a flow cross sectional area, 2 m k c head loss coefficient g mass velocity, sm kg ⋅ 2 m& mass flow rate, s kg p pressure, 2 m kn p∆ pressure differences, 2 m kn u velocity, s m v specific volume, m 3 /kg x quality ( mass dryness fraction) s slip ratio greek symbols α void fraction ρ density , 3 m kg 2φ two-phase multiplier subscript c throat section g gas f liquid fo liquid only ob obstruction non-dim. non-dimensional sf superficial liquid sg superficial gas tp two phase l liquid al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� introduction: flow systems involving a mixture of air-water(gas-water) have many applications in chemical, and mechanical industries and in nuclear – power generation. the systems usually contain straight pipes, valves, abrupt changes of section and bends. these components of pressure losses are of particular importance since these losses can be large proportional of the local pressure drop, especially in natural circulation systems where the total pressure drops can have an effect on convicted flow rate. pressure drops with obstructions in two-phase flow are usually expressed by multiplying the single – phase pressure drop by a twophase multiplayer. the two-phase multiplier depends on several parameters, one of them being the relative velocity between these two phases. chisholm(1967) has developed a correlation for the pressure drop for the two-phase flow in pipes and through orifices and ventures, which introduced the shear forces between the phases. beattie(1973) adopted the mixing length theory to drive correlation for pressure drop in spacers in reactor cores and orifices. salcuden et al. (1983) investigated experimentally the local pressure drop due to obstruction in horizontal air-water flow for different shapes and sizes obstructions. the local pressure drop was found depends strongly on the kinetic energy and momentum of liquid intercepted by the flow obstruction. simpson et al.(1985) correlated an experimental data for the two-phase pressure losses through valves and other pipe fitting. the effect of compressibility and mass transfer were analyzed and presented in terms of a correlation factor to the pressure loss multiplier. salcuden et al. (1988) measured the local pressure drop for single and two-phase flows through obstruction along a vertical and a-horizontal channel. the results have indicated that the pressure drop depends strongly upon the size and the location of the blockage. tapucu et al (1988) obtained experimentally and analytically the local pressure losses due to plate and smooth blockage under two-phase flow conditions in a square vertical channel. the analysis used based on the janssen-kerrinen and momentum energy models. the irreversible pressure loss coefficient for plate and smooth blockages was found depends on the blockage severity and void fraction. mahood et al.(2003) performed analytically the pressure drop of two-phase flow due to obstruction in vertical pipes. the analysis contained different type and shapes of obstructions. the high pressure drop were demonstrated when large obstruction used. in this work, the influence of the degree of flow blockage and the shape of the flow on pressure drop were computed using an analytical solution for different obstruction sizes and shapes which illustrated in figure (ap). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� analytical approach : the local pressure drop of two-phase flow due to obstruction is usually expressed in terms of a two-phase multiplier, as: .)( . 2 ob l tp fo p p ∆ ∆ =φ (1) the local single-phase (liquid) pressure drop due to obstruction may be calculated by using the momentum conservation through obstruction region (see fig.a�) as: )](1)[( 2 2 2 2 2 a a a ag pp c cl c −=− ρ (2) where pc and ac refers to the pressure drop and cross-section area at the obstruction and downstream region respectfully. for two-phase (air-water) flow, the local pressure drop due to obstruction may be calculated as:( see figure ap) upstream region obstruction region downstream region air +water flow 1 c 2 fig.(aq): arrr schematic diagram for present flow obstruction (3) dividing eq.(3) by eq.(2) , gives an expression for two-phase multiplier as: (4) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� the void fraction )(α is unknown and a simple analytical solution for a two-phase multiplier is generally unobtainable, however a value may be calculated if simplistic two-phase flow model are assumed. using separated flow model that is assumes that the two-phase flow are separated flow such that a set of equations may be written for each phase. therefore a slip in taken place between the twophase will be occurs due to the differences velocities, hence,the slip ratio (s): between f g u u s = (5) where ug and uf is gas and liquid velocity respectfully . and the relationship between the gas and liquid velocities with there superficial velocities can be given respectively as: α sg g u u = (6) and ( )α− = 1 sf f u u (7) substituting eq.(6) and eq.(7) into eq.(5) yield: ( ) sl sg u u s α α− = 1 (9) and the slip void fraction can be calculated from well known formula salcuden et al. (1983)as: 1 ] )1( 1[ − ⋅ − += s x x f g ρ ρ α (10) now, substituting eq.(9) into eq.(10) and substituting the result into eq.(4) given: ( ) ( ) 1 1 12 +         − +        − = sg sf g f sf sg fo u ux u ux ρ ρ α α α α φ (11) in gas-liquid two-phase flow (i.e. two components , two-phase flow) the effects of compressibility can be allowed through a compressibility factor k , such that: ( ) ( )predictedkcorrected fofo 22 φφ ⋅= (12) with : ( ) 1 2 11 −             ∂ ∂ −+ ∂ ∂ += p x p xgk νν (13) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� the effect of compressibility (k) , were studied and computed for air-water two-phase flow by simpson et al.(1985), their were found to be very small , usually with a maximum value less than 2%. therefore this effect can be ignored and the original equation eq.(11) is valid. from eq.(1), the two-phase pressure drop due to obstruction can be calculated as : ( ) ( ) obfobfotp pp ∆=∆ 2φ (14) the single-phase (liquid) pressure drop due to obstruction can be calculated from the relation salcuden et al. (1983) : 2 2 1 ffkf ucp ρ=∆ (15) where k c is total head loss coefficient of obstruction given in table (1) salcuden et al. (1983) for different sizes and shapes. and ( ) ( ) g f g f u x x u ρ ρ α α − − = 1 1 (16) sub. eq.(6) into eq.(16) yields: sg f g f u x x u ρ ρ α )1( )1( − − = (17) substitute eq.(17) into eq.(15) yield 2 )1( )1( 2 1       − − =∆ sggkf u x x cp ρ α (18) now, the local two-phase pressure drop due to obstruction can be calculated by using eq.(14) together with eq.(11) and eq.(18) . the dimensionless pressure drop calculated by using the relation salcuden et al. (1983): ( ) ( ) 2 .dim 2 1 sff obtp nontp u p p ρ ∆ =∆ − (19) results and discussion: figures(1)and (2) gives comparison between the present (analytical) work results with different results given by salcudean et al.(1983). it is shows that the chasholm (1967),experimental of central obstruction and homogeneous model results is identical with present work. while the bottom segment gives the bigger divergent from the present work, although, both results have the same behaviors. from figure(2) the same state as shown in figure (3) with a few divergent between the bottom segment experimental and theoretical results. figure (3) and figure (4) gives the relationship between the present analytical nondimensional pressure drop and experimental results al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� for 25% and 40% vertical segment obstruction. they are clearly shows that the 40% obstruction area gives a best agreement between the present and experimental results than 25% and the 40% obstruction area has a high values of non-dimensional pressure drop than 25% because of that the increasing in obstruction area in stream flow tends to intercept a much amount of fluid flowing and of cores caused a high pressure drop. figure (5)and figure (6) gives the relationship between the theoretical (present) and experimental results of salcudean et al. (1983) for bottom segment obstruction. they are showed a similar behavior indicated in figure (3)and (4) with a highest values of non-dimensional pressure drop for 40% obstruction area than the 25% figure(9) and figure (10) shows a comparison between present analytical results and experimental results of salcudean et al.(1983). the figures shows a very good agreement orientated for both 25% and 40 % central obstruction area results with the same notes indicated for 40%which has a highest nondimensional pressure drop than 25%. from all results given a good agreement obtained between the theoretical (present) and experimental results for both 25% and 40% obstruction area with noting that the 40% obstruction area has a best agreement than the 25%. conclusions: a correlation study on the two-phase multipliers and local pressure drop for two-phase , airwater mixture flows through obstructions in horizontal channel was made , leading to the following main conclusions : 1the pressure drop was strongly depended upon the obstructed blockage size . 2for two-phase flow , this generally means that obstructions mainly intercepting the liquid phase will cause large pressure drop . 3the correlation presented can be used for valves , orifice , and sudden changes in flow crosssections . 4a good agreements between the predicted values and experimental data given by salcuden et al. (1983): . references: (beattie, d. r. h. ,1973)” a not on the calculation of two-phase pressure losses “ , nucl. engr. des. , v. 25 (395) . (chisholm, d,1967)”pressure gradients during the flow of incompressible two-phase mixtures through pipes , ventures and orifice plates “,chemical engr. v.12, no.9(1368). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� (mahood ,h.b , farhan l. resheed and ali s. baqir ,2003)" two-phase pressure drop through obstruction" iraqi j. che. pet. eng., vol.4, june. (simpson , h.c. , roony, d.h. and callander , t.m.s,1985)”, pressure loss through gate valves with liquid – vapor flows “, 2 nd . international conference on multiphase flow,lodon, england , june 1921 , bhra , fluid engineering center , 67-80 . (salcudean, m. , groeneved, d. and leung, l,1983)”effect of flow-obstruction geometry on pressyre drops in horizontal air-water flow”, int. j. multiphase flow, vol.9, no.1, 73-85. (tapucue,a. , teyssedeu , n. , trouche and merilo,m, 1988)”pressure losses caused by area in a single – channel flow under two – phase flow conditions”, int. j. multiphase flow, vol.15, no.1 , pp. 5164. table.1. head coefficients for obstructions in horizontal tow-phase flow obstruction type k c (25%) k c (40%) central horizontal segment vertical segment peripheral bottom segment 0.91 0.76 0.75 0.69 2.19 2.11 2.15 2.06 a b d obstruction support li qu figure a2: shape and location of the obstruction in the channel. acentral, bhorizontal segment, cvertical segment and dbottom segment. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� n o n -d im e n si o n a l p re ss u re d ro p usg (m/s) usg (m/s) al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٤ effects of biomass growth on pressure drop in submerged aerated bioreactors dr.dheyaa wajid abbood al-mustansiryiah university college of engineering tbstraca a semi-empirical model was developed to predict biomass-affected porosity, specific surface area and pressure drop as a function of the biomass concentration in two selected submerged aerated biorectors (sabrs). under similar conditions two bench-scale sabrs (1m long and 100mm diameter) were operated to treat an industrial wastewater, the first packed with porcelinaite rocks and the other with polystyrene grains at hydraulic loading rates of ( 0.1–3.2 m/h) and with bod5 concentration of (110436 mg/l) . typical constant that can be used to estimate pressure drop for some of the most common design of sabrs were correlated. the proposed equations in porosity and specific surface area caused by biomass accumulation in sabr bed are based on macroscopic estimates of average biomass concentrations. in comparison to biofilmbased models, the macroscopic models are relatively simple to implement and are computationally more efficient. the effects of biomass accumulation and distribution on pressure losses and removal efficiency of biological load in sabrs were experimentally studied. localized biomass accumulation in the sabr beds is the key factor increasing the pressure drop, which was caused by local bed clogging due to biomass growth. the highest pressure drops in the beds (porcelinaite rocks: 2,150 n/m3 and polystyrene grains: 1115 n/m3) occurred where there were high biomass levels. the pressure drop varied nonlinearly with the amount of accumulated biomass and the amount of oxygen consumed. porcelinaite rocks caused greater pressure drops, on average 2 times higher than the polystyrene grains. compaction, as a consequence of biomass growth and porcelinaite rocks degradation increased the pressure drop in the porcelinaite rocks bed.a comparison of the experimental and the predicted pressure drops showed that the model provided good estimates of biomass-affected porosity and pressure drop in the sabrs packed with spherical grains with even biomass distribution. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٥ keywords: pressure drop, aerated submerged bioreactor, biomass growth, porcelinaite rocks تأثیر نمو الكتلة الحیویة على هبوط الضغط في مفاعل حیوي غاطس مهوى ضیاء واجد عبود.د الجامعة المستنصریة كلیة الهندسة :المستخلص تم تطویر نموذج شبه تجریبي للتنبأ بتأثیر الكتلة الحیویة على المسامیة، المساحة السطحیة النوعیة .ي مفاعلین حیویین غاطسین مهواةوهبوط الضغط كدالة تركیز الكتلة الحیویة ف ) ملم قطر للمفاعل �ôå é١٠٠ � ١(ُشغل المفاعلین تحت نفس الظروف بمقیاس مختبري بحجم تم حشو المفاعل االول بصخور البورسیلینات . وباستخدام میاه صناعیة عادمة من معامل النسیج في بغداد وتركیز للطلب االوكسجین الحیوي ) ساعة/م ٣.٢ – ٠.١(واالخر بحبیات البولیستایرین بمعدل حمل هیدرولیكي ).لتر/ملغم ٤٣٦ – ١١٠( bod5الكیمیاوي تم تعییر المعامالت الثابتة المستخدمة لتقدیر هبوط الضغط في تصامیم المفاعالت الحیویة الغاطسة تاثرة بتراكم الكتلة الحیویة اعُتمد في تخمین المعادالت المقترحة للمسامیة والمساحة السطحیة النوعیة الم. المهواة .في المفاعالت الحیویة الغاطسة على النماذج المایكرویة لمتوسط تراكیز الكتال لحیویة باالعتماد على النماذج الكتلة الحیویة، ُوجد ان النماذج المایكرویة بسیطة نسبیًا في االستخدام وحسابیًا یعها على هبوط الضغط وكفاءة االزالة مع الحمل الحیوي في ُدرست تأثیر تراكم الكتلة الحیویة وتوز .غیر مكلفة ان تراكم الكتلة الحیویة في االوساط المسامیة للمفاعالت الحیویة . المفاعالت الحیویة الغاطسة المهواة تجریبیاً . هي عامل اساسي لزیادة الضغط بسبب انسداد هذه االوساط بفعل النمو الكتلي الحیوي وفي وسط حبیبات ٣م/نیوتن ٢١٥٠في وسط صخور البورسیلینات كان اعلى هبوط ضغط وجد ان هبوط الضغط یتغیر الخطیُا مع كمیة . عند مستویات علیا للكتلة الحیویة ٣م/نیوتن ١١١٥البولیستایرین . الكتلة الحیویة المتراكمة ومع كمیة االوكسجین المستهلك ضغط عالي بلغ مرتان من ھبوط الضغط المسبب اظھرت النتائج ان صخور البورسیلینات سببت ھبوط ان تاثیر الرص كمتسلسة لنمو الكتلة الحیویة ساھم ي ازدیاد وھبوط الضغط في . بواسطة حبیبات البولیستایرین بینت نتائج مقارنة القیاسات التجریبیة والمقدرة لھبوط الضغط ان تخمین النموذج النظري . صخور البورسیلینات .لة الحیویة على المسامیة والضغطجید لتاثیر الكت introduction submerged aerated biological filter sbaf is economically efficient technology for industrial wastewater, and also used for the biological treatment of moist, dilute airstreams contaminated with odorous, toxic, and volatile organic compounds (leson and winer 1991). the pollutants are degraded by a microbial community that develops under optimized conditions of humidity, temperature, and ph within the bed. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٦ in a biofilter, the synthesis of microbial mass (biomass) by the mineralization of biodegradable pollutants leads to biomass growth and accumulation over time, which has been related to an increase in flow resistance in the bed [e.g., kinney et al. (1996) and mohseni et al. (1998)]. biomass accumulation, which is greater at the inlet sections of biofilters (corsi and seed 1995), leads to a change in bed characteristics, such as the reduction of the interparticle void space and the compaction of natural packing materials, which cause channeling and increased pressure drops. this translates into higher operating and maintenance costs that become significant for long-term biofilter operation. a better understanding of the growth of biomass in biofilters and the effects on flow may lead to improved designs with reduced energy requirements, lower operating and maintenance costs and increased removal capacities. this knowledge will also help to identify sources of operational problems and to formulate measures for improving the biofiltration process. three distinct approaches to model microbial growth and accumulation processes in porous media include the continuous biofilm, discrete micro colony, and macroscopic approaches (baveye and valocchi, 1989).the biofilm approach assumes continuous and uniform biomass growth on the exposed surface of each particle in a porous medium. taylor and jaffe (1990a, b, c) and taylor et al. (1990) used this assumption to derive analytical expressions to model changes in porous media properties due to biological growth. however, as pointed out by baveye and valocchi(1989), taylor and jaffe's (1990) experimental study presented no supporting evidence to verify the actual growth patterns and film thicknesses of the attached biomass. cunningham et ai. (1991) also proposed expressions to model the influence of biofllm accumulation on hydrodynamics in porous media. however, use of these expressions is limited to cubically packed spherical media with particles of uniform diameter alternatively, vandevivere and baveye (1992a, b) support the microcolony model forbiomass growth since they observed discrete microbial colonies in a biologically active saturated sand column. microbial growth inside the column was sparse and heterogeneous. in reality, growth patterns in porous media are more likely a combination of the two models, where microbes initially grow in discrete colonies and gradually expand to form continuous biofilms (rittmann, 1993). therefore, the macroscopic approach, the third alternative which considers only spatially averaged biomass concentrations, is a more realistic option for describing al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٧ biomass in porous media. this option offers more adaptability because it does not suppose any specific growth pattern. it is also the approach most commonly reported in the literature (corapcioglu and haridas, 1984). moreover, in most microbially mediated transport studies involving porous media, experimental data for microbes are reported only as average biomass concentrations (taylor and jaffe, 1990). the biomass layers appeared very gel-like and had a high water content and high concentrations of extracellular polymeric substances (epss) (morgan-sagastume 1999). the pressure drop through a biofilter bed typically ranges from 20 to 100 pa/m and can even go up to 1000 pa/m, and typical superficial air velocities may vary from 5 to 500 m 3 /m 2 h (devinny et al. 1999). systems with adequate moisture control and a porous medium containing bulking agents will typically achieve pressure losses <900–1,700 pa/m (leson and smith 1997).various researches have reported flow pressure losses in biofilters in relation to the bed particle size (van langenhove et al. 1986; corsi and seed 1995); nature and composition of the filter medium (mohseni et al. 1998); bed content (sabo et al. 1993); and time of operation. some studies have related increases in pressure drop to biofilm growth and clogging by biomass (hodge et al. 1992). for example, liu et al. (1994), working with granular activated carbon columns for toluene removal, measured increased pressure drops of up to 12 kpa/m due to biomass accumulation and airflow channeling. in general, the increase in pressure drop as a result of biomass development in biofilters can be explained by a decrease in the bed interparticle void space or the effective porosity or both and by the microbial degradation of the support matrix, as in the case of natural media, which result in decreased specific permeability. although the effect of biomass accumulation on pressure drop has been studied in biotrickling filters treating a gaseous stream (okkerse et al. 1999), there has not been detailed, quantitative research on this phenomenon in biofilters. the aim of this paper is to: model changes in porosity and specific surface area caused by biomass accumulation in porous media. the macroscopic approach is adopted and used attached biomass concentration as the model variable to describe variations in porous media properties. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٨ study the influence of biomass accumulation on pressure drop in submerged biological aerated reactor that treat organic compounds. model pressure losses caused by biomass growth in sabr using semi empirical models. evaluate the interparticle porosity and pressure drop changes due to biomass accumulation in a sabr. pproacha experimental 1-experimental setup a biofiltration system consisting of two identical laboratory scale sabrs were used to treat industrial wastewater from wooltextile industry in baghdad plate(1). for each biofilter, wastewater was passed through stainless steel column (100mm diameter and 1m height), packed and regulate its temperature in the sabr in the range of 24 – 26oc. a small and controlled airflow from the inlet air-stream was compressed and passed through a stainless-steel vessel which then was fed to the top of the sabr. the biological oxygen demand bod5, chemical oxygen demand cod, and total solids ts were monitored every run from wastewater samples taken at the inlet and the outlet of each sabr.manometer was used to measure differential pressure along segments of the beds, between axial ports located at the top, middle, and bottom of each section.the minimum detectable differential pressure reading of the manometer was 2.5 pa (0.25mm. water).the amount of biomass developed on the packing materials was assessed in both biofilters from bed composite samples taken from the top and bottom of each bioreactor. sampling was performed on a periodic basis, every 2–3 weeks. in total, eight samplings were performed during this experiment. after sampling, the packing material within each biofilter was remixed to ensure a uniform biomass distribution at the beginning of each period of operation. 2-packing media one sabr was packed with sieved porcelinite rock (1228kg dry /m 3 bioreactor ) with a size range of (2.5-4mm). these types of porcelinite rock were used successfully in previous biofiltration experiments. the porcelanite rocks samples used al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٩ in this study were supplied from the general company for geological survey and mineralogy-ministry of industry and minerals (gcgsm).the porcelanite rocks were prepared for the present work by grinding and sieving to obtain a grain size range (0.65-0.8) mm (passing 0.8mm standard sieve and retained on 0.65mm sieve) and then washed with distilled water and dried in an oven at 105oc for 4hr. the porcelanite rock has been analyzed by the method used in (gcgsm); the result is shown in table (1). chemically, diatomite consists primarily of silicon dioxide (sio2), and is essentially inert. it is attacked by strong alkalizes and by hydrofluoric acid, but it is practically unaffected by other acids. because of the intricate structure of the diatom skeletons that form diatomite, the silicon dioxide has a very different physical structure from other forms in which it occurs. the chemically combined water content varies from 2 to 10%. impurities are other aquatic fossils (sponge residues, radiolar, and silica-flagellate), sand clay, volcanic ash, calcium carbonate, magnesium carbonate, soluble salts, and organic matter. the types and amount of impurities are highly variable and depend upon the conditions of sedimentation at the time of diatom deposition. the table (1) indicates that the silica content of the iraqi deposits are 70.4% which is around 20% lower than that of american and spain deposits with higher content of cao and l.o.i. with it is high quality the iraqi porcelanite is highly competitive in spite the presence of iron when compared with the usa and algerian diatomite table (2). iron content is one of the important factors for the determination of mineral quality, as iron can form complexes when diatomite is used in chemical and biochemical process. table (3) indicates some physical analysis for iraqi rocks. the color of pure diatomite is white, or near white, but impurities such as carbonaceous matter, clay, iron oxide, volcanic ash, may darken it. the refractive index ranges from 1.41 to 1.48. diatomite is isotropic. the true specific gravity of diatomite is 2.1-2.2; the fusion point average about 1590co for pure material. the other sabr was packed with polystyrene (32 kg dry /m3 bioreactor; with diameters of (4-6mm), eight liters of packing material were randomly packed in each sabrs al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٠ the polystyrene have been successfully used in sabrs, and they were used in this experiment because they provide interference-free biomass quantification and have a defined spherical shape and size for pressure drop modeling. 3hydrodynaic modeling in packed beds with biofilm growth, if the biofilm thickness remains small compared to the effective pore space, accumulation of biofilm will not significantly affect the distribution of fluid velocities within a porous medium (cunningham et al . 1990). however, if the biofilm occupies a significant fraction of the effective pore space, a decrease in porosity will occur as shown in figure(1). it is possible to reduce the number of variables appearing and to make this compact results ((equation or chart) applicable to all similar situation.investigations consider the bed of porous media as composed of a number of capillary pores, passing in parallel, straight through the depth of the bed .in this case the head loss in high flow velocity (turbulent flow) depend upon capillary water velocity (vc), dynamic viscosity ( m ), density ( r ). using dimensional analysis (buckingham p theorem), general form of the empirical relationship can be constructed as follow: (1) g v dl h c c 2 1 (re) 2 y= d vc = bna q = n v z. (2) and n= " "v (3) where l: length of capillary (l), m : dynamic viscosity (m/l.t), r : density (m/l3), g: standard acceleration of gravity,(9.81m/s2),dc: inside diameter of capillary(l) and vc: velocity of fluid in capillary (l/t). n : bulk porosity of bed of porous media (l3/l3), " v : volume of the voids (l3), " : total volume of the bed (l3), z : tortuosity (l/l). al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣١ (re)y is function to reynolds number (re) which is one of the most important dimensionless parameters in high flow velocity in porous media and its size determines the nature of flow. turbulent flow in pipe, friction factor can be evaluated from (blasius formula): f= 25.0re 316.0 (4) similar to (blasius formula) the hydraulic resistance factor ( fc ) in porous media can be simulated as function to friction factor and as the form: cf = 25.re fc ¢ (5) and repore= sn v )1( 4 -m rz (6) where fc ¢ : constant depends upon porosity(n),uniform factor ( f ),and grain shape of media.because of extreme complexity of grains shape of the media and its arrangement (spacing between the grains) most of the advance in understanding the basic relation have been developed around experiments on grains shape or initial specific surface area per volume of clean substratum (m 2 /m 3 ), so which is defined as: (7) r no . )1(3 f so= the average shape or sphericity factor for the porcelinite spherical grain size was assumed to be 0.85, based on values of ( 0.75-0.95 ) for nearly spherical of various sand types (perry and green 1988). the expression proposed for calculating biomass-affected porosity nb in a bed packed with spheres, where biomass grows uniformly on the sphere surfaces(figure (1)): nb=no-nfv (8) mr" = o b n n 1 1 (9) al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٢ mr" = (1 r lb )3 4 n ( r lb )2 (2 r lb + 3 ) (10) where : f = sphericity factor for the packing solids;n0 = initial porosity of the bed without biofilm l3/l3; nb = the biomass-affected porosity; nfv = volume fraction of the biomass (l 3 biomass/ l 3 total);lb = biofilm thickness ( l), mr" = accumulative volume ratio of the packing medium (l 3 biomass/ l 3 bed); r = radius of a sphere equivalent to the packing medium l ; and n = number of packing spheres in contact with a single sphere or coordination number. eq. (10) was deduced for spheres in contact, upon which biofilm grow uniformly, leaving the contact points uncovered. the coordination number n that accounts for the number of contact points among the spheres can be estimated from an expression (dullien 1992) correlating porosity n cpd vjg cqqrdkpcvkqp pumbgr hqr c clqug rcpdqm v{rg qh rcckkpi n=13.84 ± (191.4 –231.9 n) (11) the thickness lb of the biofilm growing on the packing material can be calculated as follows: lb= b x r (12) where x = superficial biomass concentration (g biomass/m 2 surface area); and r b = biofilm density (g biomass/m 3 biomass) (m biomass/l 3 biomass).. the fraction of volume occupied by the solid-phase biomass can be estimated as : mr" = b ms x r r (13) where xm is the mass (dry weight) of microbial cells per unit mass of solids(m of microbial mass /m of bed). based on volume balances, a simple macroscopic equation volume fraction of the biomass fvn can be expressed as : fvn = )1(. 3 1 -"mrrf so (14) al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٣ volume fraction of the biomass fvn can be approximate as function to specific surface area, and biofilm thickness ( taylor et al. (1990)) fvn = lb so (15) using this porosity relationship, equations ( 7) and (8) are modified to estimate biomass-affected specific surface area (sb) values sb= )1(. )1(3 r l r n b b + f (16) for computing specific surface area reduction , biomass-affected specific surface area ratio related to porosity ratio can be expressed as 5.0)( o b b o n n s s = (17) values of specific surface area are typically unimportant except in the biofilm approach where they are required to compute film thicknesses. although the macroscopic approach does not explicitly consider biofilms, it is possible to estimate apparent biofilm thicknesses through macroscopic model-based equations (17) . these film thicknesses can be useful in modeling diffusion limitations across attached biomass (rittmann and mccarty, 1981). analytical models for predicting changes in porosity and specific surface area due to microbial growth in porous media are developed from a macroscopic approach. variations in sabr properties are computed from macroscopic averaged attached biomass concentrations. the macroscopic models developed in this work are easy to implement and computationally more efficient than the bioftlm models. the macroscopic expressions can be explicitly used to estimate biomass-affected porosity and specific surface area, at any attached biomass concentration. since the biofilm models of taylor et al. (1990) are implicit functions of attached biomass thickness, these porous media properties cannot be estimated explicitly. a comparison of experimental results and estimated results based on our macroscopic biofilm models is presented for predictions of relative changes in al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٤ porosity (figure(1)). simulation experiments started with clean media( without biomass) which the head loss in sabr can be formulated as follow : 75.175.125.1 3 25.1 25.0 } )1( {)( vs n n c l h f zr m ¢= d (18) analyses of experimental results show that the effect of biomass on head loss per bed depth in sabr s can be evaluated by the modified equation 75.175.125.1 3 25.1 25.0 } )1( {)( vs n n c l h f zr m ¢= d mr" (19) for modeling the effect of biomass on pressure drop in sabr s using the above equations, the following assumptions are made: -the packing material is composed of homogenous particles. biomass grows uniformly on the surface of spheres or of other particles with an equivalent diameter of a sphere of the same surface area. the spheres remain in contact during biomass accumulation, which assumes biofilm growth on the whole surface of the spheres; and -biomass has a constant density within the biofilm, which can be assumed at a macro scale, even if at a micro scale there is strong evidence of high biofilm heterogeneity (bishop 1997). experimental results at the highest flow rates, the increase in pressure drop and the increase of the degree of curvature of the lines suggest that kinetic energy losses became important. the kinetic energy losses as a function of the flow rate squared and the reduction of the bed porosity figure (1).the general approach in modeling the effects of biomass accumulation on pressure drop in the polysteren biofilter involved estimating porosity changes and pressure drops in the sabr based on the experimental concentrations of biomass (g biolayer/g dry substratum) and on waste water flow rates (figure(2)).the comparsoin between the experimental results of head loss of water per bed depth and proposed equation (19) gives acceptable approximation (figure(3)). localized high biomass content in the sabr beds was the key factor affecting increased pressure drop in both sabrs caused by local clogging or local void space al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٥ reduction or both.the effect of accumulated an incremental amount of biomass for different times and on pressur drop were correlated with a reasonable approximation in figures (4) to (6) . the pressure drop in the porcelinite rock biofilter was twice that in the polysteren sabr. this difference was believed to be due to greater biomass growth in the porcelinite rock bed (polysteren polysteren: 0.4–3.2 g biolayer/g dry substratum; porcelinite rock: 0.5– 19 g biolayer/g dry substratum) and a different pore structure biofilm thickness values were first estimated from the biomass concentrations (g biolayer/g dry substratum) in the bed. for this, the biomass concentrations were converted from grams of biolayer per grams of dry substratum to grams of biomass per square meters of substratum surface, using the dry substratum bulk density and an estimated initial superficial area of the packed substratum . differences between predicted and experimental pressure drops in the polystyrene sabr and porcelinite rock sabr before remixing are due to uneven biomass distribution at high biomass concentrations, which is not thoroughly characterized by averaging biomass concentration over a specific bed volume. the profiles of detached biolayer for both the polysteren sabr and porcelinite rock sabr show that most of the biomass accumulated in the first half of the bed and the biomass concentrations in the porcelinite rock bed were roughly 180% to 210% higher than in the polysteren sabr . the biomass accumulation on the porcelinite rocks bed played the main role in controlling the pressure drop increase, compared to compaction. high concentrations at the top of both the polysteren sabr and porcelinite rock sabr on day 76 in the porcelinite rock sabr correspond to the observed formation of biomass layers (0.3–0.4 cm) on the top of these sections, which caused the highest pressure drops during the experimental period biomass water content in these layers was as high as 29–61 g water/g ts in the polysteren biofilter, compared to 13–15g water/g ts in the rest of the bed, and in the porcelinite biofilter as high as 97–122g summary concentrations · asemi empirical model was developed to predict pressure drop from biomass concentrations in a sabr bed by modification the pressure drop in porous media equation as a function of bed porosity and biomass affected porosity. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٦ the model is a good estimate for predicting biomass-affected porosity in beds packed with spherical particles where biomass grows evenly distributed, and it successfully predicts pressure drop for the case of even biomass growth on spherical particles as follow: 75.175.125.1 3 25.1 25.0 } )1( {)( vs n n c l h f zr m ¢= d mr" · the optimal utilization of a sabr bed strongly depends on biomass distribution within the bioreactor and not just on the amount of biomass growing on the packing material. the highest pressure drops in the beds were caused by layers of biomass which increased the biomass specific volume and significantly decreased the bed porosity at the top levels of the biofilters. · porcelinite rocks sabr caused greater pressure drops, on average 2 times higher than the polystyrene sabr. compaction, as a consequence of biomass growth degradation, together with water content, increased the pressure drop in the porcelinite rocks bed. · the proposed models can be used as simple tools for estimating changes sabr properties during biological process. references 1. auria, r., morales, m., villegas, e., and revah, s. (1993). ‘‘influence of mold growth on the pressure drop in aerated solid state fermentors.’’ biotechnology and bioengineering, 41(11), 1007–1013. 2. bailey, j. e., and ollis, d. f. (1986). biochemical engineering fundamentals, 2nd ed., mcgraw-hill, new york. 3. baveye, p. and v. a. valocchi. 1989. an evaluation of mathematical models of the transport of biologically reacting solutes in saturated soils and aquifers. water resources research. v. 25, pp. 1413-1421. 4. bishop, p. l. (1997). ‘‘biofilm structure and kinetics.’’ water sci. and technol., 36(1), 287–294. 5. corapcioglu, m. y. and a. haridas. 1984. transport and fate of microorganisms in porous media: a theoretical investigation. journal of hydrology. v. 72, pp. 149-169. 6. corsi, r. l., and seed, l. 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(1992). 18th ed., american public health association, washington, d.c. 23. taylor, s. w. and p. r. jaffe. 1990a. biofilm growth and the related changes in the physical properties of a porous medium. i. experimental investigation. water resources research. v. 26,pp. 2153-2159. 24. taylor, s. w., p.c.d. milly, and p. r. jaffe. 1990. bioftlm growth and the related changes in the physical properties of a porous medium. 2. permeability. water resources research. v. 26, pp.2161-2169. 25. taylor, s. w. and p. r. jaffe. 1990b. bioftlm growth and the related changes in the physical properties of a porous medium. 3. dispersivity and model verification. water resources research. v. 26, pp. 2l7l-2180. 26. taylor, s. w. and p. r. jaffe. i99oc. substrate and biomass transport in a porous medium. water reso~ research. v. 26, pp. 2181-2194. 27. vandevivere, p. and p. baveye. 1992a. saturated hydraulic conductivity reduction caused by aerobic bacteria in sand columns. soil science society of america journal. v. 56, pp. 1-13. 28. vandevivere, p. and p. baveye. 1992b. relationship between transport of bacteria and their clogging efficiency in sand columns. applied environmental microbiology. v. 58, pp. 2523-2530. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٣٩ 29. van langenhove, wuyts, h. e., and schamp, n. (1986). ‘‘elimination of hydrogen sulphide from odorous air by a wood bark biofilter.’’ water res., 20(12), 1471–1476. table (1): chemical analysis for porcelanite local sample used in this study. constituent (%) silica (sio2) 68.40 alumina(al2o3) 1.56 iron oxide (fe2o3) 0.63 titanium oxide (tio2) 0.11 phosphate (p2o5) 1.48 lime (cao) 9.42 magnesia (mgo) 5.39 sodium (na2o) 0.64 potassium (k2o) 0.36 ignition loss (l.o.i.) 11.15 total 99.14 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٠ table (2): typical chemical analysis of diatomite in some different countries and iraqi rocks. constituent % lompocu.s.a. japan spain kenya algeria iraq silica (sio2) 89.72 86 88.6 84.5 75.93 70.4 alumina(al2o3) 3.72 5.8 0.62 3.06 0.98 1.75 iron oxide (fe2o3) 1.09 1.6 0.2 1.86 3.3 0.79 titanium oxide (tio2) 0.1 0.22 0.05 0.17 0.125 0.1 phosphate (p2o5) 0.1 0.03 0.00 0.04 13.74 1.98 lime (cao) 0.3 0.7 3 1.8 1.87 10.75 magnesia (mgo) 0.55 0.29 0.81 0.39 2.32 2.1 sodium (na2o) 0.31 0.48 0.5 1.19 0.7 0.59 potassium (k2o) 0.41 0.53 0.39 0.91 n.a. 0.14 ignition loss (l.o.i.) 3.7 4.4 5.2 6.08 5.02 10.42 total 99.98 100.05 99.37 100 99.08 99.02 n.a.: not analyzed table (3) physical analysis for iraqi rocks. sample no. density (kg/m3) porosity (%) specific gravity 1 1221 39.302 2.026 2 1228 45.613 2.217 3 1609 25.407 2.148 4 1396 32.706 2.067 5 1403 41.206 2.381 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤١ pppp plate (1): the pilot system fig.(1): the effect of biofilm thickness on bed porosity for different bed materials. n =0.5833 -0.0011 lb r 2 = 0.9051 n = 0.5961-0.0013 lb r 2 = 0.9075 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 biofilm thickness lb (micro m) b e d p o ro si ty n ( % ) polysterene porcelinite figure (1) the effect of biofilm thickness on bed porosity for different bed materials fig.(2): the effect of influent rate in generated biofilm thickness on porcelinaite bed surfaces. lb= 98.767e-1.1938 q r2 = 0.8689 20 30 40 50 60 70 80 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 influent rate (cubic m/h) b io fi lm t h ic k n e s s ( m ic ro m ) figure (2) the effect of influent rate in generated biofilm thickness on porcelinaite surfaces al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٢ fig.(3):-the comparsoin between proposed and measured head loss per bed depth in porcelinaite sabr y = 9.2795e0.0068 lb r2 = 0.9026 y = 10.275e0.0063 lb r2 = 0.962 0 10 20 30 40 50 60 70 80 90 100 110 120 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 biofilm thickness (micro m) h e a d l o s s (m m p e r m b e d d e p th ) dh/l proposed dh/l measured figure (3) the comparison between proposed and measured head loss per bed depth in porcelinaite sabr fig.(4): the effect of influent on pressure drop per unit bed depth of sabr for different clean bed materials. p/l = 30.963e 2.849q r 2 = 0.9983 p/l= 15.202e 3.2176q r 2 = 0.9939 0 50 100 150 200 250 300 350 400 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 influent ( cubid m/h) p re ss ur e d ro p pe r be d de pt h (p a/ m ) polysterene porcelinite figure (4) the effect of influent on pressure drop per unit bed depth of sabr for different clean bed materials al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٣ fig.(6): the effect of biofilm thickness on pressure drop per polysterne bed depth in sabr . p/l= 72.531e0.0081 lb r2 = 0.9334 p/l= 97.379e0.007 lb r2 = 0.9026 p/l = 61.256e0.0082lb r2 = 0.9881 0 200 400 600 800 1000 1200 1400 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 biofilm thickness (micro m) p re ss u re d ro p p er b ed d ep th (p a/ m ) 72 days 91 days 124 days figure (6) the effect of biofilm thickness on pressure drop per polysterne bed depth in sabr fig.(5): the effect of biofilm thickness on pressure drop per porcelinite bed depth in sabr . p/l = 61.384e0.0073 lb r2 = 0.9335 p/l = 102e0.006lb r2 = 0.9181 p/l = 169.83e0.0045 lb r2 = 0.9641 0 100 200 300 400 500 600 700 800 900 1000 0 50 100 150 200 250 300 350 400 biofilm thickness lb( micro m) p re ss u re d ro p p e r b e d d e p th ( p a /m ) 60 days 75 days 90 days figure (5) the effect of biofilm thickness on pressure drop per porcelinaite bed depth in sabr article al-qadisiyah journal for engineering sciences 15 (2022) 081–086 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: waqass.s.khudhir@uotechnology.edu.iq (waqass khudhir) https://doi.org/10.30772/qjes.v15i2.817 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. experimental investigation of metal removal and micro-hardness during maf process waqass s. khudhir production engineering and metallurgy, university of technology/ baghdad iraq a r t i c l e i n f o article history: received 08 may 2022 received in revised form 06 june 2022 accepted 15 july 2022 keywords: magnetic abrasive finishing metal removal rate feed rate micro-hardness a b s t r a c t this work aims to provide an experimental investigation into metal removal and micro -hardness through the magnetic abrasive finishing process (maf) and study the impact of some process parameters (feed rate, coil current, and spindle speed) on these responses with (1008-aisi) workpieces and spherical electromagnetic tool based on taguchi design of the experiment using minitab 17 software. the results show that metal removal was strongly affected by the feed rate, while the strongly influential variable on micro-hardness was the coil current. the highest value of metal removal rate is achievable at conditions 10 mm/min, 2.5 a, and 700 rpm for feed rate, coil current, and spindle speed respectively. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction magnetic abrasive finishing (maf) is an electro-magnetic field-assisted process. the forces in this process are controlled by the magnetic field. the movement made by the pole brush and fixed plate work surface will cause a little amount to be removed from the workpiece and produce a mirror finishing surface [1,2]. the machining gap between the magnetic pole and workpiece is filled by abrasive powder which is consist of abrasive and iron powder plus a binder material because of the relative motion that occurs the abrasive friction force will cause the work surface machining [3]. due to the flexibility of the magnetic brush, the machined surface will be free of the micro-cracks that appeared by traditional finishing processes such as grinding which uses a rigid tool [4]. joshi et al. (2014) investigated the cylindrical maf process of brass and cast iron workpieces using an electromagnetic pole. the results prove that the increase of coil turns to increase the metal removal due to the increase that occurs in magnetic flux. the initial surface roughness and hardness were taken into account to make a comparison between the initial and final values of both hardness and roughness [5]. yuewu et al. (2020) studied the finishing process of (ss304) plate by maf process utilizing three types of abrasive powder (diamond particles embedded in a spherical iron matrix, cbn, and alumina). the study included four machining parameters which are the size of magnetic abrasive powder, rotational speed, gap, and feed rate on the responses to metal removal and surface roughness. finite element analysis was used to estimate the normal pressure of magnetic abrasive powder. the results illustrated that the diamond powder was the best one when compared with the other powder which gives higher material removal and better finish at the same machining conditions [6]. nazar kais m. naif (2012) investigated the effect of some machining parameters during the maf process. the abrasive powder is made from quartz and iron powder with percentages of 60%, and 40 % respectively. the experiments were performed on the brass plate (cuzn33) and the output responses are surface roughness and microhardness [7]. o. kadhum (2018) predicted the value of the working time which obtains the required value for metal removal and surface roughness http://qu.edu.iq/ mailto:waqass.s.khudhir@uotechnology.edu.iq https://doi.org/10.30772/qjes.v15i2.817 https://doi.org/10.30772/qjes.v15i2.817 http://creativecommons.org/licenses/by/4.0/ https://www.sciencedirect.com/science/article/abs/pii/s0020740319345084#! 82 waqass s. khudhir /al-qadisiyah journal for engineering sciences 15 (2022) 081–086 through designing and implementing an automated machine. the values were predicated by controlling the machining factors (velocity of the magnetic pole, electromagnetic voltage, machining gap, and machining time) during the maf process. as a result of this work, about 97% for metal removal and 95% for surface roughness were the matchings between predicted values and experimental results [8]. s. shather and m. abd (2019) studied the metal removal and surface roughness during the maf process utilizing different concentrations and mesh sizes of silicon carbide as the abrasive powder. as a result of this study, the higher metal removal was0.004 g gained using 25% si and 75% fe with1.5 mm gap and 100 μm mesh size. the optimum change in surface roughness was 0.007 μm utilizing 33% si and 67% fe, gap 2 mm and, 200 μm mesh size. [9]. the main aim of this work is to study the impact of machining parameters on the metal removal and microhardness of machined surfaces during the maf process. . 2. experimental procedure maf is performed on an nc milling machine, which is used to control the tool movement. in this work, the tool is a spherical electromagnetic tool with a (20 mm) diameter which is shown in fig.1, whereas fig.2 illustrated the machined sample it consists of an iron core covered with copper wire. the specimens of (1008-aisi) plate with dimensions (100 x 50 x 0.9) mm, were used to implement the 9 experiments. the workpiece’s chemical composition is shown in table1. the experiments were carried out at rotation speed 700 rpm and the density of magnetic field 1113.5, 3047.6, 4415.9 µ tesla for 1.5, 2, 2.5 a respectively. figure 1. experimental setup figure 2. machined sample table 1. workpiece (aisi-1008) chemical composition composition c si mn s p cr weight (%) 0.08 0.02 0.32 0.024 0.014 0.035 composition ni mo v cu al fe weight (%) 0.032 0.002 0.001 0.072 0.044 remain a50 percent is mixed from tungsten carbide and pure iron powders were performed to get the magnetic abrasive powder with 350°c sintering temperature after the sintering process the high ball mill and sieving machines were utilized to have a 300 µm mesh size of the magnetic abrasive powder. the process parameter levels are shown in table 2. table 3 illustrates the taguchi l9 orthogonal array of the parameters. the hardness was measured, before and after the maf process, the differences in hv values at three different locations, and then the value was averaged by utilizing a micro-hardness tester device. table 2. the proposed control parameters and their levels symbol input parameters level 1 level 2 level 3 unit a feed rate 10 20 30 mm / min b coil current 1.5 02 2.5 ampere c spindle speed 500 600 700 rpm waqass s. khudhir /al-qadisiyah journal for engineering sciences 15 (2022) 081–086 83 table 3. taguchi l9 orthogonal array no. of experiment machining parameters levels a b c 1 10 1.5 500 2 10 2 600 3 10 2.5 700 4 20 1.5 600 5 20 2 700 6 20 2.5 500 7 30 1.5 700 8 30 2 500 9 30 2.5 600 3. results and discussion table 4 and table 5 illustrate the experimental results of metal removal and hardness respectively. table 4. experimental metal removal and s/n results no. of experiment machining parameters levels mrr (g) s/n (db) f cc ss 1 10 1.5 500 0.009 -40.9151 2 10 2 600 0.029 -30.7520 3 10 2.5 700 0.044 -27.1309 4 20 1.5 600 0.003 -50.4576 5 20 2 700 0.018 -34.8945 6 20 2.5 500 0.003 -50.4576 7 30 1.5 700 0.007 -43.0980 8 30 2 500 0.001 -60.0000 9 30 2.5 600 0.010 -40.0000 fr: feed rate (mm / min) cc: coil current (ampere) ss: spindle speed (rpm) table 5. experimental microhardness and s/n results the main effect plot of metal removal and microhardness are illustrated in fig. 2 and fig. 3 respectively. figure 3. main effect plot of metal removal from fig. 3, it is clear to see lower metal removal when higher feed rate, because more magnetic abrasive passes into the machining gap with lower feed rate values, which causes an enhancement of metal removal. on the other side, the abrasive particle passes quickly with increasing the feed rate and produces a small amount of metal to be removed from the machining zone. increasing the magnetic flux density means more material removal. the increase in tool rotational speed will cause an increase in the value of metal removal. the reason behind this action is belonging to a higher no. of experiment machining parameters levels ∆hv s/n (db) fr cc ss 1 10 1.5 500 8.21 18.2869 2 10 2 600 14.21 23.0519 3 10 2.5 700 20.75 26.3404 4 20 1.5 600 11.65 21.3265 5 20 2 700 6.20 15.8478 6 20 2.5 500 29.50 29.3964 7 30 1.5 700 10.30 20.2567 8 30 2 500 19.00 25.5751 9 30 2.5 600 21.38 26.6002 fr: feed rate (mm / min) cc: coil current (ampere) ss: spindle speed (rpm) 84 waqass s. khudhir /al-qadisiyah journal for engineering sciences 15 (2022) 081–086 frictional force occurs at a higher rotational speed because of the irregular jumbling of the abrasive that happened under these conditions, which produces over-removal of the material by the aggressive strikes of the jumbling abrasives. figure 4. main effect plot of microhardness figure 5. signal-to-noise plot of metal removal fig.4 demonstrated when increasing the rotational speed, the normal magnetic force will decrease that meaning a decrease in the improvement of surface hardness. at high speed the magnetic abrasives will splash from the machining gap when normal magnetic force decreases, fig.4 also illustrated it seen that the increase in coil current causes the change in micro-vickers hardness to increase. a higher number of indentations in the workpiece surface occur when increasing the coil current because of an increase in the strength of the magnetic brush [9]. some influence of feed rate on change in micro-hardness is illustrated in figure 4, the increases in feed rate values from (10 to 30) mm/min an improvement occurs in the change in micro-hardness. figure 6. signal-to-noise plot of microhardness fig 5. and fig.6 illustrated the signal-to-noise ratio for metal removal and microhardness respectively, from fig.5 can be noticed that the maximum values of the s/n ratio were obtained at the lower level of feed rate and the higher level of coil current and spindle speed. fig.6 demonstrated that the maximum value of the s/n ratio at higher levels of feed rate and coil current whereas the lower level of spindle speed results in the maximum value of the s/n ratio. fig7. and fig.8 represent the effect of input parameters on metal removal, from these figures can be observed that the highest value of metal removal achievable at the lower right corner of the contour plot where the maximum value of coil current and spindle speed while the feed rate at the minimum level. this is because the abrasive particle passes quickly with increasing the feed rate and produces minimizes the metal removal to be removed from the machining zone. from fig.9 can be observed that the highest value of metal removal was obtained at the upper right corner at the maximum levels of both coil current and spindle speed. this attribute can be explained due to higher frictional force occurring at a higher rotational speed. fig.10 demonstrated the impact of the feed rate and coil current on the microhardness of the machined surface, from this figure can be noticed that the highest value of microhardness was obtained at the upper right corner at the maximum levels of both coil current and spindle speed. fig. 11, and fig. 12 illustrated the highest value of microhardness was obtained at the upper left corner at the minimum level of spindle speed and maximum levels of coil current and feed rate. fig. 13 illustrated the magnetic density utilized in this work for the individual value of coil current. from this figure can be noticed that the highest value of magnetic density is 4415.9 µ tesla, whereas the lowest value is 1113.5 µ tesla coil current f e e d r a t e 2.502.252.001 .751 .50 30 25 20 1 5 1 0 > – – – < 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04 mr contour plot of mr vs feed rate, coil current waqass s. khudhir /al-qadisiyah journal for engineering sciences 15 (2022) 081–086 85 figure 7. effect of feed rate and coil current on metal removal figure 8. effect of feed rate and spindle speed on metal removal figure 9. effect of feed rate and coil current on metal removal figure 10. effect of feed rate and coil current on microhardness figure 11. effect of feed rate and spindle speed on microhardness figure 12. effect of coil current and spindle speed on microhardness figure 13. magnetic density (µtesla) spindle speed c o il c u r r e n t 700650600550500 2.50 2.25 2.00 1 .75 1 .50 > – – – < 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04 mr contour plot of mr vs coil current, spindle speed spindle speed f e e d r a t e 700650600550500 30 25 20 1 5 1 0 > – – – < 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04 mr contour plot of mr vs feed rate, spindle speed spindle speed c o il c u r r e n t 700650600550500 2.50 2.25 2.00 1 .75 1 .50 > – – – < 1 0 1 0 1 5 1 5 20 20 25 25 delta hv contour plot of delta hv vs coil current, spindle speed coil current f e e d r a t e 2.502.252.001 .751 .50 30 25 20 1 5 1 0 > – – – < 1 0 1 0 1 5 1 5 20 20 25 25 delta hv contour plot of delta hv vs feed rate, coil current spindle speed f e e d r a t e 700650600550500 30 25 20 1 5 1 0 > – – – < 1 0 1 0 1 5 1 5 20 20 25 25 delta hv contour plot of delta hv vs feed rate, spindle speed 86 waqass s. khudhir /al-qadisiyah journal for engineering sciences 15 (2022) 081–086 references [1] tudor, andrea "magneto-abrasive finishing of complex surface" romanian association of nonconventional technologies, december (2013). [2] sumit1, yogesh2, gaurav chhikara3"modern magnetic abrasive finishing process". international journal of enhanced research in science technology & engineering.vol. 3 issue 6, june 2014, pp: (460-462). [3] japman singh1 , radhey sham2"experimental investigation of process parameter of maf on surface roughness" international journal of science, technology , and management, 'sgi reflections', may (2013). [4] dhirendra k. singh, v. k. jain, v. raghuram, "superfinishing of alloy steels using magnetic abrasive finishing process", aspe.net/ publications/annual_ kanpur208016 (india) corresponding author(2003). [5] rishi dev joshi, dr. gursewak singh brar, mithlesh sharma., “effect on magnetic abrasive machining with different range of electrical parameters”, international journal of emerging technology and advanced engineering, vol. 4, issue 9, sep.(2014). [6] yuewu gao yugang zhao guixiang zhang fengshi yin haiyun zhang "modeling of material removal in magnetic abrasive finishing process with spherical magnetic abrasive powder", international journal of mechanical sciences, volume 177, 1 july 2020, 10560. [7] nazar kais m. naïf, “study on the parameter optimization in magnetic abrasive polishing for brass cuzn33 plate using taguchi method, “the iraqi journal for mechanical and material engineering, vol. 12, no.3, (2012). [8] o. chasib kadhum, " design and fabrication of automated predictive magnetic abrasive finishing machine" a msc thesis university of baghdad, 2018. [9] s. k. shather and m. abdal-khadim abd alaqeeli "influence of silicon carbide (sic) abrasive on surface roughness and metal removal rate during magnetic abrasive finishing", global journal of engineering science and research management, issn 2349-4506, 2019. [10] a. kumar, johan verbert, bert lauwers, and joost r. duflou, "tool path compensation strategies for single-point incremental sheet forming using multivariate adaptive regression splines", computer aided design – elsevier, vol. 45, pp. 575-590, 2013 4. conclusions in this work, metal removal and microhardness have been investigated experimentally using three machining factors on (1008-aisi) workpieces based on the taguchi design of the experiment. the following conclusions are listed: 1the investigation was conducted by considering the varying parameter of (feed rate, coil current, and spindle speed) with the taguchi method. 2the (feed rate) is the most influential variable for the metal removal flowed by speed and then coil current. 3the (coil current) is the most influential variable for the microhardness flowed by speed then feed rate. . https://www.sciencedirect.com/science/article/abs/pii/s0020740319345084#! https://www.sciencedirect.com/science/article/abs/pii/s0020740319345084#! https://www.sciencedirect.com/science/article/abs/pii/s0020740319345084#! https://www.sciencedirect.com/science/article/abs/pii/s0020740319345084#! https://www.sciencedirect.com/science/article/abs/pii/s0020740319345084#! https://www.sciencedirect.com/journal/international-journal-of-mechanical-sciences https://www.sciencedirect.com/journal/international-journal-of-mechanical-sciences/vol/177/suppl/c article al-qadisiyah journal for engineering sciences 14 (2022) 211–218 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ali.shokor49@uomustansiriyah.edu.iq (ali s. golam) https://doi.org/10.30772/qjes.v14i3.795 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. lifting capacity efficiency using polyethylene beads: a numerical investigation ali s. golam a*, mohammed h. alhamdoa, assan a. abdul husseinb, sinan i. mohammed c a mechanical engineering department, college of engineering, mustansiryah university, baghdad, iraq b petroleum engineering department, college of engineering, baghdad university, baghdad, iraq c oil research and development centre / ministry of oil, baghdad, iraq a r t i c l e i n f o article history: received 00 december 2021 received in revised form 00 january 2022 accepted 00 february 2022 keywords: cfd ansys-fluent eulerian-eulerian well cleaning polyethylene (pe) beads a b s t r a c t global demand growth has driven the development of more inventive methods for enhancing oil well drilling at lower prices and avoiding operational issues that slow down oil well drilling. the present research is significant because the lifting capacity may be increased by inserting polymer beads into drilling mud instead of high-cost additives. the numerical cuttings trajectory simulation was performed using the commercial ansys fluent 2019 r3 software to account for the influence of cuttings collisions. to test the cuts transport behavior owing to the presence of liquid and solid phases, the (eulerian-eulerian) model was utilized. the mind transfer rate is determined in this simulation by varying the operating parameters (drilling mud flow rate and temperature, cuttings size and inclination, drill pipe rotation and eccentricity) with and without polyethylene (pe) beads. the result show that the average error ratio between the results of the numerical simulation is 5 % with the experimental results of researcher ismail. the higher the percentage of pe beads entering with the drilling fluid, the lower the concentration of the cuttings within the annular space of the simulation model. the concentration of cuttings within the annular space reaches 28 % when drilling fluid flows at a speed of 1.2 m/s without adding polyethylene pe beads. while it decreases to (17, 21, 24) % when adding beads by (6, 4, 2) %, respectively, at the same flow velocity of drilling fluid. the decrease in the concentration of cuttings within the annular space of the simulation model reaches 14 % when pe beads are inserting with drilling fluid by 6 % and the drill pipe rotation speed is 0 rpm, while the percentage increases to 65 % when the drill pipe rotation speed is increased to 120 rpm at the same ratio of pe beads entering with the drilling fluid. the reduction percentage of the cuttings concentration within the annular space of the simulation model reaches 30 % when 6 % of pe beads are entered into the drilling fluid at a temperature of 20 ℃, while the percentage is reduced to 14 % when the drilling fluid temperature is 50 ℃ at the same percentage of pe beads is inserting. the inserting of polyethylene (pe) beads with the drilling fluid has increased the ability of the drilling fluid to move the cuttings, but it is affected by the amount of drilling angle, as we found that the effect of the polyethylene (pe) beads is effective and clear when the drilling angle is 0˚ (vertical). while its effect becomes less at the drilling angle of directional wells and becomes very weak at the drilling angle of 90˚ (horizontal).the inserting of polyethylene (pe) beads with drilling fluid has a good and positive effect with large-sized cuttings when compared with the impact of the beads with smaller-sized cuttings. © 2022 university of al-qadisiyah. all rights reserved. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 212 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 1. introduction interest in resolving problems associated with cleaning the bottom of the well and conveying the cutting to the surface has lately increased while using directional and horizontal oil well drilling technologies. cleaning the well throughout the drilling process is a critical factor in influencing the cost, duration, and quality of the oil well drilling process. effective cleaning requires immediately getting the cutting to the well's surface. numerous academics have extensively used numerical calculations and approaches to tackle a wide variety of drilling fluid flow problems, as well as their relationship to cutting transport under a variety of operating conditions. mehmet sorgun. [1] explained how cuttings from horizontal and deviated wells are transported to the surface using experimental and computational methods. the middle east technical university in petroleum and natural gas engineering performed the experiment. use water and other drilling fluids to investigate the characteristics and behavior of cuttings. drilling pipe rotation (0-120 rpm) and borehole inclination (0-60) degrees were also investigated. a mathematical approach to forecast drilling fluid flow in a horizontal concentric ring has been suggested. the navier-stokes equations for turbulent flow were numerically solved (matlab 2007). the drilling fluid flow rate has been shown to be the most important factor in cutting transport. the rotation of the drill pipe also lowers the production of fixed cuttings, however this benefit diminishes with flow rate. the theoretical model also effectively forecasts frictional pressure loss and loop velocity profile. hussain h. et al. [2] used continuity equations, navier-stoke, and the force law to describe non-newtonian fluids to convey cuts to the well surface. fluent software was used to simulate. three kinds of drilling mud were used in the studies. a drilling location in sudan provided the feeding conditions and cutting size. the influence of cuttings shape was tested at (600-900) gpm and cuttings size (2.54, 4.45, and 7) mm. the findings revealed that fine clippings are the easiest to raise and clean the well. the finest cleaning results were observed while drilling at 30 degrees and using an 800 gpm flow rate. xiaofeng sun et al. [3] simulated drilling fluid flow numerically using a multi-phase euler model. the most essential characteristics impacting cuttings layer development are flow rate, hoof slope, and rotation speed. the drill pipe was simulated at an inclination of 45-90 degrees and a rotation speed of 80-240 rpm with a flow rate of 30-50 l/s. this rotation increases cutting transmission and helps disperse cuttings asymmetrically during runoff. the impact of rotating the drill pipe is strong when the drilling fluid flow rate is low or medium. satish and shobha. [4] drilling mud flow via a spinning inner ring was analyzed. the influence of several parameters on cuttings transport efficiency was evaluated, including drill pipe rotation speed, drilling mud flow rate and type, and cuttings concentration inside the test loop. the data were evaluated to explain the mixture's pressure drop, slip velocity, and kinetic energy distribution inside the test ring. for multi-phase liquids, the (fluent 12.0) software employed the (eulerian-eulerian) model, and the (simplec) method for speed and pressure. the simulation model was evaluated against existing research data. oil-based drilling fluids boost the cohesiveness of undesirable cuttings layer. however, water-based drilling fluid aids in cuttings loosening. the transfer efficiency of the cuttings varies depending on various characteristics. titus and ismail. [5] used (ansys cfx-15) software to simulate a multi-phase liquid (eulerian-eulerian) model. the particle size ranged from 90 to 270 microns, and their concentration ranged from 10% to 40%. the k-epsilon model was selected to apply with existing experimental data. the findings indicated that as particle size grew, flow pressure loss increased. reducing the cutting size helps decrease pressure loss. behnam and mohammad. [6] used a numerical model to solve liquid and solid flow equations (cuttings). the (eulerian-eulerian) model was adopted to predict particle behavior during flow. the degree of convergence was verified by comparing numerical findings to experimental data. flow rate, pipe rotation, slope, and cutting size were all tested extensively. the findings indicated that cuttings transfer efficiency reduces between 45-60 degrees. increasing burr rotation and flow velocity also improves cleaning efficiency. mostafa keshavarz et al. [7] employed a (ke) turbulent model and a multiphase (eulerian-eulerian) model to describe three-phase flow inside a concentric ring. to verify the numerical simulation, the results were compared to earlier operations. these included drill pipe rotation, water and air flow rate, cutting size and inclination. the findings revealed that rotating the drill pipe between (0-75) rpm reduces cuttings concentration, whereas rotating between (75-125) rpm increases cuttings concentration. the rotation of the drill pipe has a stronger impact on little particles than big items. the concentration within the well rises with increasing air flow, reduced inclination, and drill pipe rotation. emmanuel and dimitrios. [8] ansys fluent 17.1 was used to evaluate two-phase flow in a well loop. these factors included drill pipe deviation, tilt, rotation, rate of penetration (rop), and drilling fluid rheology. particle motion was modelled using an eulerian-eulerian multi-phase tracking model. the numerical model was validated by comparing simulation results to experimental data (error rate less than 11 percent). the findings indicated that the drilling fluid velocity, pipe inclination, and deflection are the most important elements affecting cuttings transit efficiency. ali zakerian et al. [9] employed a simulation software to explore parameter effects on cutting transport. the drilling fluid type, cutting density, and concentration ratio were studied using fluent software. the findings revealed that increasing the drilling fluid density lowered cuttings concentration in the test tube by 32.9 percent while decreasing pressure. increasing the cuttings density from the operational density increases the cuttings concentration within the ring nomenclature 𝑣𝑚 mixture velocity (m/s). subscripts 𝜌𝑚 mixture density (kg/𝑚 3). cfd computational fluid dynamics. 𝑣𝑠 solid velocity (m/s). e-e eulerian-eulerian. 𝜌𝑠 solid density (kg/𝑚 3). mtm mixture turbulence model 𝑣𝑙 liquid velocity (m/s). dtm dispersed turbulence model. 𝜌𝐿 liquid density (kg/𝑚 3). wbm water-based mud. 𝐺𝑘 generation of k due to mean velocity gradients. cvc cuttings volumetric concentration. 𝐶1,𝜖 , 𝐶2,𝜖 constant. cc cuttings concentration. 𝜖 volume concentration rpm revolutions per minute. 𝛼𝑠 volume concentration of cuttings. e eccentricity. 𝛼𝐿 volume concentration of drilling fluid. 213 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 by 200 percent. it is feasible to tailor the drilling fluid density to the cuttings density. boxue pang et al. [10] the influence of flow rate, inclination, rotation of the drill pipe and drilling fluid viscosity on cuttings uplift. to verify the numerical model's accuracy. the findings converged well with earlier experimental data. the findings revealed that increasing flow rate helps minimize cutting layer thickness. another finding is that transporting cuttings at an angle of (35-65) degrees is the most problematic. changing the drill pipe's rotation speed has no impact on transferring cuttings. siamak and majid. [11] simulated cutting transport using cfd-dem (cfddem). the drag force, lift, and pressure gradient associated with two-phase flow were utilized. the model investigates cuttings collision and transmission, as well as cuttings bed mechanics. drilling fluid velocity, inclination, and rotation were examined. the findings demonstrated that when the drill pipe rotates, a layer of cuttings forms inside the inner walls of the ring, which thickens with decreasing flow velocity. after the drill pipe's rotation speed reaches the crucial speed for high flow rate, no more rotational contribution is made. when the hoof slope is 40 degrees, rotating the drill pipe helps minimize cutting thickness. mortatha al-yasiri et al. [12] employed computational fluid dynamics (cfd) to solve multi-phase flow issues. the influence of (the drilling fluid rheology, drill pipe rotation, flow rate, cuttings density, shape and focus) on the efficiency of lifting cuttings in vertical wells. multi-phase liquid flow was simulated using dspm and eulerian-eulerian models. the numerical findings demonstrated that a range of factors impact the efficiency of transporting cuttings. among the factors, the drilling fluid flow rate has the greatest impact on cleaning efficiency. however, increasing the cuttings density and concentration within the simulated test model reduced the drilling fluid's capacity to move the cuttings. xiaohua et al. [13] presented an experimental and numerical simulation study of the use of a pulsed drilling fluid to transport the cutting bed. a three-dimensional simulation model was created to transport the cuttings in the horizontal wells in conformity with the experimental model and studied the effect of the velocity of the pulse drilling fluid on the cutting velocity and its ability to break up the layer accumulations of the horizontal wells. the results showed that the use of a pulsed drilling fluid helps to increase the cutting speed, reduce its concentration, and improve the cleaning of the well bottom. rasel a. et al. [14] created a fluid dynamics computer model that simulates multi-phase flow systems for parameter prediction. the computational model's correctness was verified by comparing numerical simulation results to experimental data. for multi-phase runoff, including liquid (water), gas (air), and solid (sand), the ansys fluent 16.2 software was utilized (sand). particle size and concentration, flow rate, and pressure gradient were studied. the study's findings validated the suggested simulation model and demonstrated its use in many applications, including oil and gas. mohsen and moarefvand. [15] on well cleaning efficiency using computational and experimental methods. a numerical simulation using a computational fluid dynamics (cfd) model of liquid and solid flow was done (eulerian-eulerian). concerning viscosity, (k-epsilon) was addressed, and the suggested model was validated using experimental data. the experimental part involves developing a functional model with a stationary outer pipe and a spinning inner pipe powered by an electric motor. an electric motor and gearbox inject cuttings at varying rates. a variable capacity pump supplies drilling fluid to the annular vacuum. the test pipe may be slanted to suit the investigation. the findings indicated that viscosity boosts cleaning efficiency. however, the findings revealed an undesirable critical angle of drilling (30-55) degrees that should be avoided. dongsheng wen et al. [16] simulated the effect of nanoparticles on drilling fluid performance. used computational fluid dynamics (cfd) to deal with multi-phase flows and flow issues. the influence of drilling fluid rheology, flow rate, cuttings density, shape, and concentration on drilling fluid efficiency was examined. the findings demonstrated that adding nanoparticles to the drilling fluid increased its rheological characteristics and hence its capacity to clean the well. mastaneh hajipour. [17] used a concentric pipe to dig a horizontal well. (cfd) is used to solve two-phase flow equations with solid particles (cuttings). a horizontal ring with 1.9 in inner and 2 in outer diameter was created. several models were used to determine the hydrodynamic inlet length, which came out to 40 ft. it was shown that drilling mud qualities (low and high viscosity) were affected by operational parameters such as penetration rate and drill pipe rotation. the ratio of solid particles inside the well ring was used to assess cuttings movement. the findings demonstrated that the drill pipe's rotation encourages solid particle movement and slows their sliding. increasing the drilling mud flow rate reduces the influence of bore tube rotation. increasing viscosity helps the components move but increases the drilling mud's resistance to rotation. although substantial researches has been done on cuttings transport and hole cleaning, further research is needed to validate the influence of operational factors on lifting capacity. on the other hand, we found that many of the materials added to drilling mud to improve the lifting capacity may be expensive or not applicable due to the large quantities required to be prepared for drilling mud. also, we did not find interest in conducting studies on the inserting of materials with drilling mud without changing the chemical drilling mud specifications. 2. numerical model numerous modeling approaches exist to describe multi-phase flow. the most significant of them are euler-lagrange, euler-euler, volume of fluid, and dispersed phase. in the present investigation, the euler-euler model was used. to analyze the flow behavior of cuttings and drilling mud in the annulus, the eulerian-eulerian (e-e) two-phase flow model was utilized. interactions between the two phases are described by introducing extra source terms into the conservation equations. 2.1. model geometry the flow geometry is an annulus created by two cylinders. the inner and outer cylinders represent the drill pipe and borehole, respectively. drilling fluid is poured into the drill pipe and the annulus transports drill cuttings to the surface. the annulus may be hundreds of feet in diameter and form a fully developed flow. as a consequence, a fully developed annulus section was simulated to save computation time. this was accomplished by modelling a horizontal annulus with an inner diameter of 0.05 m and an outside diameter of 0.1 m. a series of simulations was used to establish the hydrodynamic entrance length. the simulated well length was fixed at 4 m in this inquiry since the hydrodynamic entrance length is less than 4 m and the flow has been determined. the drill string does not stay in the wellbore's centre during horizontal and directional drilling; it descends due to gravity. the eccentricity of a drill string is determined by the following equation: e = 𝐷 𝑅𝑂−𝑅𝑖 (1) 214 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 where (𝑅𝑖) is the drill pipe radius, (𝑅𝑜) is the wellbore radius, and (d) is the distance between the drill pipe and wellbore centres. the geometrical and operational parameters utilized in the simulation are listed in table 1. the model is created with the use of a (solid work) application, as seen in fig. 1. table 1 simulation input parameters. parameter value simulated well length (m) 4 drill pipe diameter (m) 0.0508 wellbore diameter (m) 0.1016 mud drilling density (kg/m^3) 1200 cutting density (kg/m^3) 2400 mud drilling type wbm drill pipe eccentricity (e) 0, 0.4.0.8 mud drilling temperature (℃) 20, 30.40.50 drill pipe rotation (rpm) 0, 40, 80,120 mud drilling velocity (m/s) 0.3, 0.6, 0.9, 1.2 hole inclination (˚) 0˚, 30˚, 45˚60˚, 90˚ cuttings volume (mm) (0.5-1), (1.5-2), (2.25-3), (3.5-4) figure 1 base-case flow. 2.2. mathematical modelling of turbulence [18]. primarily, three different models of turbulence are performed for modelling multiphase (k -e) disorder. these model options are: • mixture turbulence model (mtm). • dispersed turbulence model (dtm). • turbulence model for each phase. the mixture turbulence model (mtm) is the simplest of the three options. it uses mixture properties, mixing speeds and presumably captures the important features of the turbulent. it represents the first extension of a single-phase model (k-e) and is applicable when phases are separated to layers or semi-stratified stratum layers and when the density ratio between phases is close to one. in these cases, use of the mixture properties and mixture velocity is sufficient to capture the important advantage of the disturbance. the equations governing the mixture turbulence model (k-e) are given as follows: 𝜕 𝜕𝑡 (𝜌𝑚 𝑘) + ∇. (𝜌𝑚 . 𝑣𝑚.𝜖) = ∇. ( 𝜇𝑙,𝑚 𝜎𝑘 ∇𝑘) + 𝐺𝑘,𝑚 − 𝜌𝑚 . 𝜖 (2) and 𝜕 𝜕𝑡 (𝜌𝑚 𝜖) + ∇. (𝜌𝑚 . 𝑣𝑚.𝜖) = ∇. ( 𝜇𝑙,𝑚 𝜎𝜖 ∇𝜖) + 𝜖 𝑘 (𝐶1,𝜖 𝐺𝑘,𝑚 − 𝐶2,𝜖 𝜌𝑚. 𝜖) (3) the mixture velocity and density (𝑣𝑚 and 𝜌𝑚) are computed respectively, by the following relationship: 𝜌𝑚 = ∑ 𝛼𝑖 𝜌𝑖 𝑎𝑛𝑑 𝑣𝑚 = ∑ 𝛼𝑖 𝜌𝑖 𝑣𝑖 𝑁 𝑖=1 ∑ 𝛼𝑖 𝜌𝑖 𝑁 𝑖=1 (4)𝑁𝑖=1 this takes the following form for two phases (solid– liquid) flow case: 𝜌𝑚 = 𝛼𝑠 𝜌𝑠 + 𝛼𝐿 𝜌𝐿 𝑎𝑛𝑑 𝑣𝑚 = 𝛼𝑠 𝜌𝑠 𝑣𝑠 + 𝛼𝐿 𝜌𝐿 𝑣𝑙 𝛼𝑠 𝜌𝑠 + 𝛼𝐿 𝜌𝐿 (5) 2.3. meshes generated dynamic and static hexagonal meshes were employed in all flow modes. at the inlet and outflow boundaries, edge scaling and face meshing methods were utilized to generate a high-resolution image capable of capturing boundary conditions. it was vital to preserve a high degree of orthogonally and low skewness in the mesh; hence, the outer pipe divisions were equal to the interior pipe divisions. to determine the best number of elements necessary to deliver an accurate solution while using the fewest feasible computer resources, a grid size independence study was conducted on all pipe eccentricities considered fig. 2. as seen in fig. 3, the concentric flow configuration requires more elements than the eccentric annuli configuration in order to give an independent solution regardless of the grid size. figure 2 sensitivity analysis of grid size. figure 3 mesh generated. 215 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 2.4. boundary conditions in this work, the boundary conditions are shown in fig. 4. the velocity (inlet limits type) and (appropriate size portions) of the secondary stages have been imposed at the inlet. the outlet boundary pressure type of the outlet has been performed; its pressure value is set equal to the atmospheric pressure. moreover, the non-slip condition of the interior and exterior walls has been considered. figure 4 boundary conditions. 2.5. simplifications and assumptions simplifications and assumptions have been completed respectively. all have been listed below to solve this problem: 1the liquid phase is an incompressible non-newtonian fluid. 2the cuttings are spheres shapes 3between two phases, there is no interfacial mass transport. 4slippage velocity is neglected. 5effect of shear stress and shear strain is neglected. 6the kinetic energy of the particles is not conserved. 3. material preparation 3.1. drilling mud a water-based mud (wbm) has been adopted, which is actually used to drill many oil and gas wells with great depths. the drilling fluid density of 1200 kg/m^3. 3.2. polyethylene beads a buoyant force is generated when a less dense object is immersed in a higher density medium. on this basis, the idea of introducing polyethylene beads with the drilling fluid came to generate a buoyant force towards the top that may be useful in increasing the thrust resulting from the drilling fluid to move the rock pieces to the top of the surface of the well. linear low density polyethylene (lldpe) beads were used 930 kg/m^3. note that the particles entering with the drilling fluid are disc-shaped, with a diameter of 3 mm and a thickness of 1.5 mm. 4. result and discussion 4.1. numerical validation in order to reach high reliability in the use of numerical simulation programs to explain the parameters associated with the process of drilling oil wells and their impact on the ability of drilling fluid to transport cuttings, simulations of experimental models were conducted for other researcher (ismail et al. [19]) using the eulerian-eulerian model. fig. 5 show a comparison of the simulation of the experimental models of the cutting transport ratio (ctr) under the influence of changing the drilling angle. the results of the comparison of the above figures showed that the average error ratio between the results of the numerical simulation is 5 % with the experimental results of researcher ismail. from this error, it is clear that there is reliability in the use of numerical simulation programs. figure 5 comparison between experimental (ismail et al. [19]) and numerical results for variation of the hole angle and ctr. 4.2. numerical results fig. 6 shows the concentration of cuttings within the annular space of the simulation model after inserting polyethylene (pe) beads with drilling fluid. in general, we noted that the higher the speed of the drilling fluid flow, the greater the ability of the drilling fluid to transport cuttings. on the other hand, the higher the percentage of pe beads entering with the drilling fluid, the lower the concentration of the cuttings within the annular space of the simulation model. this is because the buoyancy force as a result of the density difference between the polyethylene beads and the drilling fluid causes the beads to move upward at a speed higher than the velocity of the drilling fluid flow. thus, the grains collide with the cuttings and prevent their slipping and increase the lifting force generated by the drilling fluid. where we noted that the concentration of cuttings within the annular space reaches 28 % when drilling fluid flows at a speed of 1.2 m/s without adding polyethylene pe beads. while it decreases to (17, 21, 24) % when adding beads by (6, 4, 2) %, respectively, at the same flow velocity of drilling fluid. the concentration of the cuttings within the annular space of the simulation model before and after the inserting of different proportions of pe beads with the effect of the rotation speed of the drill pipe is shown in fig. 7.from the above figure, we noticed that the higher the rotation speed of the drill pipe, the greater the ability of the drilling fluid to transport the cuttings to reduce the concentration of the cuttings within the annular space of the simulation model. also, we noted that the inserting of pe beads contributed 216 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 to reducing the concentration of cuttings, which has a greater impact when increasing the rotation speed of the drill pipe. noted, when comparing with drilling fluid without adding beads, the decrease in the concentration of cuttings within the annular space of the simulation model reaches 14 % when pe beads are inserting with drilling fluid by 6 % and the drill pipe rotation speed is 0 rpm, while the percentage increases to 65 % when the drill pipe rotation speed is increased to 120 rpm at the same ratio of pe beads entering with the drilling fluid. this is due to the fact that the forces dominating the cuttings are less effective when the drill pipe rotates. and in the presence of the lifting forces generated by the drilling fluid with the buoyancy force of the grains, the ability of the drilling fluid to move the cuttings increases. fig. 8 shows the concentration of the cuttings after inserting polyethylene (pe) beads with drilling fluid. in general, we noted that the ability of the drilling fluid to transport cuttings decreases when the temperature of the drilling fluid increases. on the other hand, we noted that the increase in the percentage of pe beads added to the drilling fluid increases the ability of the drilling fluid to transport cuttings at all temperatures. also, pe beads are more effective at lower drilling fluid temperatures compared to the high drilling fluid temperature, we noted that the reduction percentage of the cuttings concentration within the annular space of the simulation model reaches 30 % when 6 % of pe beads are entered into the drilling fluid at a temperature of 20 ℃ , while the percentage is reduced to 14 % when the drilling fluid temperature is 50 ℃ at the same percentage of pe beads is inserting. fig. 9 shows the concentration of the cuttings after inserting the polyethylene (pe) beads with drilling fluid under the influence of the change in the angle of inclination of drilling. we noted that the inserting of polyethylene (pe) beads with the drilling fluid has increased the ability of the drilling fluid to move the cuttings, but it is affected by the amount of drilling angle, as we found that the effect of the polyethylene (pe) beads is effective and clear when the drilling angle is 0˚ (vertical). while its effect becomes less at the drilling angle of directional wells and becomes very weak at the drilling angle of 90˚ (horizontal). the concentration of the cuttings within the annular space of the simulation model before and after the inserting of different percentages of polyethylene pe beads with the effect of the size of the cuttings is shown in fig. 10. from this figure, we noted that the greater the size of the cuttings, the greater its concentration within the annular space of the simulation model. also, we noted that polyethylene (pe) beads contribute to increasing the ability of the drilling fluid to transport cuttings at all sizes. the inserting of polyethylene (pe) beads with drilling fluid has a good and positive effect with large-sized cuttings when compared with the impact of the beads with smaller-sized cuttings. this is due to the fact that the cuttings of small size are pushed upwards due to the lifting force generated by the drilling fluid, and the role of the polyethylene (pe) beads is to accelerate the transport of the cuttings towards the top, while the effect of the buoyant force of the polyethylene (pe) beads is to prevent the slipping of the larger cuttings, reduce the impact of the force of attraction and weight, and increase the frequency of collisions to facilitate the task of the drilling fluid to transport the cuttings. figure 6 the (cc) after inserting (pe) beads with drilling fluid under changing the (vm) (vc = (0.51) mm, rpm = 80, e=0, t=20 ℃, ѳ=0˚). figure 7 the (cc) after inserting (pe) beads with drilling fluid under changing the (rpm) (vc= (0.5-1) mm, vm=0.6 m /s, e=0, t=20 ℃, ѳ=0˚). figure 8 the (cc) after inserting (pe) beads with drilling fluid under changing the (t) (vc= (0.5-1) mm, rpm = 80, e=0, vm=0.9 m/s, ѳ=0˚). 10 20 30 40 50 60 0 0.5 1 1.5 c c (% ) fluid velocity (m/s) nwbm nwbm+2%pe nwbm+4%pe nwbm+6%pe 20 30 40 50 60 0 20 40 60 80 100 120 c c ( % ) drill pipe rotation (rpm) nwbm nwbm+2%pe nwbm+4%pe nwbm+6%pe 30 35 40 45 50 20 25 30 35 40 45 50 c c ( % ) fluid temp (c˚) nwbm nwbm+2%pe nwbm+4%pe nwbm+6%pe 217 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 figure 9 the (cc) after inserting (pe) beads with drilling fluid under changing the (hole angle) (vc= (0.5-1) mm, rpm = 80, e=0 vm=1.2 m/s, t=20℃). figure 10 the (cc) after inserting (pe) beads with drilling fluid under changing the (vc) (vm=1.2 m/s, e=0, t=20 ℃, rpm = 80, ѳ=0˚). 4.3. comparison of reduction ratio of cuttings concentration before and after inserting (pe) beads to drilling fluid. fig. 11 shows the comparison of the (pmc) of cuttings within the first meter of the simulation model that includes the following specifications (vc= (0.5-1) mm, rpm=120, e=0, ѳ=˚90, t=20, vm= 1.2 m/s) befor and after adding 6% of pe beads. in general, we noted that the inserting pe beads with drilling fluid contributed more to increasing the ability of the drilling fluid to transport cuttings when compared with the drilling mud without inserting pe beads. according to the buoyancy theory, the greater the difference between the density of the liquid and the density of the submerged object, the greater the buoyant force is generated. therefore, a greater buoyant force is generated when pe beads are inserted with the drilling fluid, which increases the frequency of collisions, prevents the slip and stability of the cuttings, and increases the lifting force of the drilling fluid. figure 11 comparison of the (pmc) of cuttings before and after adding 6% of pe beads. (vc = (0.5-1) mm, rpm=120, e=0, ѳ=˚90, t=20, vm= 1.2 m/s). 5. conclusions 1the average error ratio between the results of the numerical simulation is 5 % with the experimental results of researcher ismail [19]. from this ratios, it is clear that there is reliability in the use of numerical simulation programs. 2the higher the speed of the drilling fluid flow, the greater the ability of the drilling fluid to transport cuttings. 3the higher the percentage of pe beads entering with the drilling fluid, the lower the concentration of the cuttings within the annular space of the simulation model. 4the concentration of cuttings within the annular space reaches 28 % when drilling fluid flows at a speed of 1.2 m/s without adding polyethylene pe beads. while it decreases to (17, 21, 24) % when adding beads by (6, 4, 2) %, respectively, at the same flow velocity of drilling fluid. 5the decrease in the concentration of cuttings within the annular space of the simulation model reaches 14 % when pe beads are inserting with drilling fluid by 6 % and the drill pipe rotation speed is 0 rpm, while the percentage increases to 65 % when the drill pipe rotation speed is increased to 120 rpm at the same ratio of pe beads entering with the drilling fluid. 6the reduction percentage of the cuttings concentration within the annular space of the simulation model reaches 30 % when 6 % of pe beads are 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 90 c c ( % ) hole angle (˚) nwbm nwbm+2%pe nwbm+4%pe nwbm+6%pe 10 15 20 25 30 35 40 0.5 1 1.5 2 2.5 3 3.5 4 c c ( % ) cutting size (mm) nwbm nwbm+2%pe nwbm+4%pe nwbm+6%pe 218 ali s. golam, mohammed h. alhamdo, hassan a. abdul hussein, sinan i. mohammed /al-qadisiyah journal for engineering sciences 14 (2022) 211–218 entered into the drilling fluid at a temperature of 20 ℃, while the percentage is reduced to 14 % when the drilling fluid temperature is 50 ℃ at the same percentage of pe beads is inserting. 7the inserting of polyethylene (pe) beads with the drilling fluid has increased the ability of the drilling fluid to move the cuttings, but it is affected by the amount of drilling angle, as we found that the effect of the polyethylene (pe) beads is effective and clear when the drilling angle is 0˚ (vertical). while its effect becomes less at the drilling angle of directional wells and becomes very weak at the drilling angle of 90˚ (horizontal). 8the inserting of polyethylene (pe) beads with drilling fluid has a good and positive effect with large-sized cuttings when compared with the impact of the beads with smaller-sized cuttings. acknowledgements i would like to thank the existing staff at oil research and development center / ministry of oil for supporting the study, providing me with the data and information related to the subject of the study, providing scientific advice and solving the difficulties i faced during this study. references [1] mehmet sorgun “modelling of newtonian fluids and cuttings transport analysis in high inclination wellbores with pipe rotation” a thesis submitted to the graduate school of natural and applied sciences of middle east technical university in partial fulfilment of the requirements for the degree of doctor of philosophy in petroleum and natural gas engineering 2010. 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[16] dongshengwen, mortatha al-yasiri and amthalal-gailani” numerical study of cuttings transport of nanoparticle-based drilling fluid” wiley, volume 2, issue 5, may 2020. [17] mastaneh hajipour “cfd simulation of turbulent flow of drill cuttings and parametric studies in a horizontal annulus” accepted: 28 may 2020 © springer nature switzerland ag 2020, sn applied sciences (2020) 2:1146. [18] boxue pang, shuyan wang, qiujin wang, kai yang, huilin lu, muhammad hassan, xiaoxue jiang “numerical prediction of cuttings transport behaviour in well drilling using kinetic theory of granular flow” journal of petroleum science and engineering, journal of petroleum science and engineering 161 (2018) 190203. [19] a. katende, b. segar, i. ismail, f. sagala, h. h. a. r. saadiah,a. samsuri (2019) “the effect of drill–pipe rotation on improving hole cleaning using polypropylene beads in water‑based mud at different hole angles” journal of petroleum exploration and production technology accepted: 24 november 2019 © the author(s) 2019. article al-qadisiyah journal for engineering sciences 15 (2022) 102–112 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: alinadhum9595@gmail.com (ali n. kassob) https://doi.org/10.30772/qjes.v15i2.820 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. treatment of petroleum refinery wastewater by adsorption using activated carbon fixed bed column with batch recirculation mode ali n. kassob*a and ali h. abbar b a department of chemical engineering, college of engineering, university of al-qadisiyah, iraq b biochemical engineering department, al-khwarizmi college of engineering, university of baghdad, baghdad, iraq a r t i c l e i n f o article history: received 17 may 2022 received in revised form 20 june 2022 accepted 22 july 2022 keywords: cod removal adsorption activated carbon response surface methodology wastewaters. a b s t r a c t water pollution and the lack of access to clean water are general global problems that result from the expansion of industrial and agricultural activities. petroleum refinery wastewaters consider as a major challenge to the environment and their treatment is mandatory. the present work concerns with the removal of chemical oxygen demand (cod) from petroleum refinery wastewater taken from iraq's al-diwaniyah petroleum refinery plant by using an activated carb fixed-bed column operated at a batch recirculation mode. the fixed bed column used in this work was composed of three sections: upper, central, and bottom compartments. the bottom compartment serves as a feeding chamber to the central adsorption chamber while the upper compartment serves as a collecting effluent chamber. by adopting response surface methodology (rsm), in the pacts of various operational parameters such as packing level, ph, and time on the cod removal efficiency were investigated. the optimal conditions were an activated carbon packing level of 80%, ph of 5.7, and adsorption time of 73 min approximately, which resulted in a cod removal efficiency of 96.70%. the results indicated that the packing level of activated carbon had a major effect on cod elimination followed by ph, while time had a minor effect. the model equation's adequacy was demonstrated by its strong r2 value (0.975). the present study demonstrates that the adsorption system by activated carbon is an effective method for removingcondomodom al-diwaniyah petroleum refinery wastewaters. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction one of the most serious environmental challenges nowadays is waste oil created by industrial sectors, particularly oil refineries and petroleum distribution businesses. [1–3]. wastewaters of oil refinery have different organic substances with a high value of cod due to the variance in characteristics of crude oil and different processes that used for treating crude oil. due to the presence of metal ions and organic hydrocarbon components in these wastewaters, their discharge without treatment can be extremely detrimental to the environment [4,5]. the importance of treating these wastes also resulted in the development of various cleaning methods, including biological treatment [5, 6], reverse osmosis [7], ion exchange resins [8,9], chemical precipitation [9], granular activated carbon adsorption [10-15], coagulation and coagulant aids [16], electrocoagulation [17,18], catalytic vacuum distillation [19], and electrochemical oxidation [20-23]. petroleum refinery wastewaters (prws) consider as refractory wastewaters which contain complex aromatics organic and inorganic compounds. wastewaters generated from refineries have been recognized as extremely poisonous and more refractory to natural http://qu.edu.iq/ mailto:eng.chem.20.post.18@qu.edu.iq https://doi.org/10.30772/qjes.v15i2.820 https://doi.org/10.30772/qjes.v15i2.820 http://creativecommons.org/licenses/by/4.0/ ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2021) 102–112 103 degradation compared to other types of wastewater generated from various industrial activities [24]. coelho et al. [25] documented that, during the production stage in oil refinery processing, the amount of water consumed varies between 0.4 and 1.6 times the volume of processed oil, resulting in substantial environmental damage. based on the complexity of the refinery, the generated wastewater in oil refineries comprises many different chemical compositions where typically cod value could be in the range of 300–600 mg/l; phenol concentration in the range of 20–200 mg/l; benzene in the range 1–100 mg/l; and heavy metals levels, for example, chromium (0.1–100 mg/l) and lead (0.2–10 mg/l) [24,26-28]. adsorption is one of the most effective procedures for reducing organic and inorganic chemicals remaining in effluents following conventional treatment. the widest adsorption process is based on the adsorption by activated carbon [29]. some of the relative advantages of adsorption over other advanced oxidation approaches include: (1) it has the capability in removing both organic and inorganic elements at extremely low concentrations, (2) there is no formation of sludge, (3) it is a simple and safe method of operation, and (4) the adsorbent is regenerable and reusable. besides, the procedure is affordable because it utilizes readily available materials that can be employed as adsorbents after proper processing [30-32]. using of adsorption contacting systems for prws treatment has become more prevalent in recent years. activated carbon is the most frequently utilized adsorbent in adsorption applications [33]. activated carbon (ac) adsorbents are complicated substances that are difficult to identify based on their behavior, surface qualities, properties, or utility. however, they are frequently categorized according to their particle shape and size, with around 55% of activated carbons produced as a powder, 40% as granular, and the remainder as pellets. around 80% of the total output (powder, granular, and pellets) is used in liquid-phase applications, whereas 20% is used in gaseous-phase applications [34]. activated carbon exhibits several unique qualities, including a high internal surface area, chemical properties, and excellent access to internal pores. there are three types of pores: macropores (diameter greater than 50nm), mesopores (diameter between 2 and 50 nm), and micropores (diameter less than 2 nm) [35]. micropores typically account for a significant portion of the interior surface area. macro and micropores can be thought of as entrances to the carbon particle. combining the appropriate raw material and activation technique results in the desired pore shape for an activated carbon product [35]. award. et al., [36] verified a matched pair method using activated carbon (ac) for refinery wastewater processing and accomplished a powerful cod elimination (90%). many works have been conducted for the treatment of petroleum refinery process wastewater using activated carbon [10-15]. most of these works adopted batch or continuous operation mode in the adsorption. however, many scientists have turned to use a reactor with a batch recirculation mode as a highly adaptable laboratory-scale reactor [37]. based on the authors’ knowledge, no previous work on the reduction of cod from petroleum refinery wastewater using granular activated carbon (ac) adsorption process operated at batch recirculation mode had been conducted. therefore, this work aims to investigate the feasibility of cod removal from petroleum refinery wastewater using granular activated carbon adsorption technology in a batch recirculation mode of operation. response surface methodology (rsm) combined with box-behnken design (bbd) was used to study and optimize the effects of main operating factors including packing level of activated carbon, ph, and time on the cod removal from wastewater produced by the al-diwaniyah petroleum refinery. 2. experimental work from the al-diwaniyah refinery plant, 50 liters of wastewater was taken from the feeding tank prior to the biological treatment unit and kept covered in containers at a temperature of 4 ºc until use. table 1 provides the specifications of the raw effluent. table 1. characteristics of the effluents in the al-diwaniyah petroleum refinery plant variable value cod 2455(mg/l) ph 7.4 t.d.s 4267 (ppm) cl2128 (mg/l) so4-2 phenol 126 (mg/l) 14.2(mg/l) turbidity 29.6 (ntu) conductivity 10.77 (ms/cm) the adsorption system was composed of a cylindrical tank with a capacity (of 1.25l), an adsorbing column, a dosing pump (type-hybl5lnpvf001, italy,) with a maximum pressure of 10 bar, and a flow rate in the range of ( 1-3 l/h), a liquid flow meter ( type-zyia,25-250 ml/min, china). the acrylic cylindrical reservoir has dimensions (20 cm in height, outer diameter of 10 cm, and thickness of 0.4cm) having a cover with dimensions (outside diameter of 12 cm and thickness of 1 cm). the reservoir has two outlets one at its bottom and the other at its lateral side located above its base at a distance of (3 cm). each outlet was provided with a pvc valve. the cover was provided with two inlets; the first is for the recycle from the adsorbing column, while the second is for feeding the solution. figure 1 shows the schematic diagrams for the adsorption system. the adsorbing column is the backbone of the adsorption system. it is a new design adopted in the present work. it was made from transparent acrylic material, perspex type. it was composed from tof compartments: upper, central, and bottom compartments. the bottom compartment serves as a feeding chamber for the adsorption process. it has a cylindrical shape with dimensions (outside diameter of 7 cm, total length of 5 cm, and thickness of 0.4 cm) ended at its upper face with a flange having dimensions (10 cm in diameter and thickness of 1cm) and contained four holes (0.5 cm in diameter) for fixing the compartment with the others via bolts and nets. the bottom compartment has an inlet pipe having a diameter of 1cm for entering the solution is located at the side of the compartment. inside the cavity the of bottom compartment, a bed of spherical glass pellets was put which serves as a calming section. the diameter of the glass bead was 0.5 cm. the central compartment has a cylindrical shape with dimensions (outside diameter of 7 cm, total length of 7 cm, and thickness of 0.4 cm) ended at its upper and lower faces with flanges having dimensions (10 cm in diameter and thickness of 1 cm) and each one contained four holes. upper flange was provided by perforated disc has dimensions (outside diameter of 6.8 cm, and thickness of 0.3cm) made from the same material of the compartment, while the lower flange was provided with the same disc as used at the upper flange. both discs were perforated uniformly with hole of 1mm at equal distance among them. the upper compartment serves as a collecting chamber. it has a cylindrical shape with dimensions (outside diameter of 7 cm, total length of 5 cm, and thickness of 0.4 cm) ended at its lower face with a flange having dimensions (10 cm in diameter and thickness of 1 cm) and containing four holes. figure 2 shows the schematic design of the adsorbing column. 104 ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2022) 102–112 all chemicals used in the present work were analytical grade, h2so4 (98%, thomas baker, india) and naoh (purity99%, bdh, england). activated carbon (zhengzhou kelan company, china). table 2 shows the characteristics of the material as provided by the supplier (company). table 2 granule activated carbon technical features. test standard astmd total surface area 950-1200 m2/g iodine number 900-1150 mg/g total ash content max.5% hardness min. 97% apparent density 460 kg/m3 moisture content 8%(as packed) particle size 8x30 mesh the bet surface area of ac was measured using iso-9277-2010 method at petroleum r &d center, ministry of oil in iraq using bet surface area analyzer model-no. qsurf9600, thermo finnegan co. usa. the ir spectra of the ac samples were obtained using a model perkin elmer 1100 series ft-ir operating in the range 4000–400 cm-1 and utilizing kbr pellets with a resolution of 1 cm-1. a pellet was created for infrared research by combining a specific sample with kbr crystals and pressing it into a pellet. figure 1. schematic diagram of the chemical system by adsorption process. before starting each experiment, activated carbon was sieved between 1.7mm and 0.85 mm then 200 g of ac was rinsed with 0.5 l of distilled water several times until its ph became 7, after that the washed ac was separated from water by filtration then dried at 100 ºc for 1hr using the oven (type-la mer, germany). 1l of wastewater was taken and poured inside a 2liters beaker mounted on a magnetic hot plate stirrer (hieroglyph, mr hei-standard, germany) then its ph was modified to get the desired value by 1m h2so4 or 1m naoh, then transferred to the reservoir of the adsorption system. a certain amount of activated carbon that corresponds to the required packing level was placed in the central compartment of adsorbing column. the dosing pump was turned on for circulating the solution through the adsorbing column at a liquid flow rate of 200 ml/min and the adsorption process was continued for some time at a constant temperature of 25±2 ºc. at the end of each run and before carrying out cod tests, the sample of treated wastewater was taken and filtered then tested for its cod value. a digital ph meter was used to measure the electrolyte ph (hnna instrument inc.ph211, romania), whereas conductivity and tds were determined by utilizing a conductivity meter model com-100 from hm digital inc. in korea. solution turbidity was measured by jenway-6035, germany. so4 -2 and cl-1 were analyzed by using photo flex. series, wtw model no 14541, germany. figure 2 schematic diagram of the chemical reactor effluent cod was used to measure the number of organic compounds in the waste stream. the quantity of cod in the petroleum refinery effluents was determined by taking a sample (0.2 ml) of effluent digested for 120 minutes at 150 °c with k2cr2o7 as an oxidizing agent using a thermos reactor (rd125, lovibond). to analyze the digested sample, it had to be cooled down to room temperature first then cod was measured by spectrophotometer (md200, lovibond). method 8047 of the hach company/hach lange gmbh, usa, was used to measure phenol concentration. the cod was measured three times, with the averages used in this study. the effectiveness of cod removal was determined using eq.1[38] 𝑅𝐸% = 𝐶𝑂𝐷𝑖 −𝐶𝑂𝐷𝑓 𝐶𝑂𝐷𝑖 × 100 (1) where the removal efficiency (re%), the initial cod (mg l1), and the final cod (mg l1) are all represented by the letters cod in the formula. when digesting a kg of cod. design of experiments response surface methodology (rsm) is summarized as a collection of mathematical and statistical tools for determining a regression model equation that correlates an objective function with its independent variables [39]. box–behnken design (bbd) was adopted to examine the impact of process variables on cod removal. the removal effectiveness of cod (re %) was considered as a response, while the packing level (x1), time (x2), and ph (x3) were taken as process parameters [39]. the scales of the process components were designated as follows: low (-1), middle or center ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2021) 102–112 105 point (0), and high level (1). table 3 shows the process parameters with their selected levels while table 4 shows the experiments array provided by bbd for the current work, which was obtained by the minitab-17 program. the amount of ac for each packing level corresponds to 10 g for 20%, 25 g for 50%, and 40 g for 80%, which results in a dose of adsorbent 10g/l, 25g/l, and 40g/l respectively. in this work, the following second-order model with the least-squares approach was used to determine the correlation between cod removal and its independent variables. [40,41]: 𝑌 = 𝑎0 + ∑ 𝑎𝑖 𝑥𝑖 + ∑ 𝑎𝑖𝑖 𝑥𝑖 2 + ∑ 𝑎𝑖𝑗 𝑥𝑖 𝑥𝑗 (2) a0 is referred to as the intercept term., x1 is the first process variable, x2 is the second process variable, and xk is the last process variable. main effects ai, aii, and aij all reflect the first order (linear) effects; the interaction effects are represented by aij. analyzing variability and then calculating a correlation coefficient (r2) confirmed the model's suitability. 3. results and discussion 3.1 characteristics of activated carbon the results of the bet surface area analysis were a bet surface area of 1204.2337 ± 39.5518 m²/g which is a desirable quality in wastewater treatment applications. the average pore volume and diameter were found to be 0.636180 cm3/g and 2.11314 nm, respectively. these are the properties of a mesoporous substance. the adsorption-desorption plot for ac was presented in fig. 3. nitrogen uptakes rose as the relative pressure increased across the whole pressure range. ac exhibited type i features with a hysteresis loop at 0.4≤ p/p≤0 0.9, which is consistent with the categorization of the international union of pure and applied chemistry (iupac). as a result, the presence of mesopores with highly absorbent surfaces were confirmed, as has been previously reported in similar investigations [42, 43]. 3.2 results of experimental design according to bbd design, fifteen runs were performed to investigate the optimum conditions for cod removal. table 5 summarizes experimental findings regarding cod removal effectiveness (re percent). results showed that the efficiency of cod removal was in the range of 84% 96.26%. as a preliminary inspection, a comparison between run(1) and run(15) showed that the packing level of activated carbon has a considerable impact on the efficiency of cod removal where re% increased from 87 to 95.9% making a difference of 8.6% as packing level of activated carbon increased from 20%to 80% at ph 5 and time of 60 min, while the comparison between run (5) and (6) showed that ph followed the packing level in its effect on the cod removal efficiency where table 3. process variables with their level for refinery wastewater treatment process parameters 𝐁𝐨𝐱– 𝐁𝐞𝐡𝐧𝐤𝐞𝐧 level levels that are coded low (-1) middle (0) high (+1) x1packing level (%) 20 50 80 x2time (min) 60 70 80 x3ph 3 5 7 106 ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2022) 102–112 table 5. experimental results of box–behnken design for cod removal run order blocks parameters re% packing level (%) time (min) ph actual predicted 1 1 20 60 5 87 87.088 2 1 20 80 5 90.24 90.688 3 1 80 70 3 91 91.663 4 1 50 80 3 89.71 89.135 5 1 20 70 7 90 89.338 6 1 20 70 3 84 84.1285 7 1 50 70 5 93.57 93.597 8 1 50 70 5 92.53 93.597 9 1 80 70 7 95.78 95.653 10 1 50 60 3 87 86.785 11 1 80 80 5 96.26 96.173 12 1 50 60 7 91 91.575 13 1 50 70 5 94.69 93.597 14 1 50 80 7 93.33 93.545 15 1 80 60 5 95.9 95.453 re% increased from 84 to 90% making a difference of 6% as the ph increased from 3 to 7 at packing level of 20% and time of 70min. however, the precise effect of these parameters can be observed via anova results. by using minitab-17 software, results of cod removal efficiency were analyzed and a quadratic model for the effectiveness of cod elimination (re percent) expressed in terms of real process parameters was formulated as follows: re% = 15.2 + 0.382 x1 + 1.079 x2 + 8.60 x3 0.000729 x1*x1 0.00591 x2*x20.686 x3*x3 0.00240 x1*x2 0.00508 x1*x3 0.0048 x2*x3 (3) where: • x1x2, x1x3., and x2x3. denote the effect of model parameters on one another. • (x1)2, (x2)2, and (x3)2 all reflect a measure of the model parameters' major effect. the expected values of cod removal efficiency were computed and summarized in table 4 using equation 3. in eq.3, the positive coefficient in front of any parameter reveals that re% increases with its increase and vice versa. the acceptability of bbd was identified by the use of analysis of variance (anova). figure 3. n2 adsorption-desorption isotherm of ac results of experimental design it is an analytical technique that utilizes fisher's fand p-tests to determine the model's and its parameters' significance [44]. in general, bigger fvalues and smaller p-values indicate that the coefficient terms are more important [45]. the response surface model is illustrated in table 6 using anova. this table contains, contr.% denotes the percentage of contribution of each variable, df represents the degree of freedom of the model and its parameters, and the statistical terms are represented by the sum of the square (seq. ss), the adjusted sum of the square (adj. ss), and adjusted mean of the square (adj. ms) respectively. p-values of (0.002) and f-value of (22.54) were obtained which elucidate that the regression model is highly significant. the model's coefficient of multiple correlations was 0.9759, indicating that the regression is statistically significant and that the model confirms only (0.0241) of the total variations. the adjusted multiple correlation coefficient (adj. r2) equals 0.9326, while the predictable multiple correlation coefficient (pred. r2) equals 0.790 in this model was well-matched since the difference between them is less than 0.2[46]. results of table 5 showed that packing level has the major effect with a contribution of 52.27% followed by ph with a contribution of 23.06%. while time has a lower effect with a contribution of 5.09%. these results confirm that adsorption is governed by two operating parameters (packing level and ph). these results are expected because during the adsorption process, with increasing ph, the negative surface charge of the adsorbents decreases, resulting in a strengthening of the electrostatic adsorption force between the adsorbent and contaminants with a positive charge, hence boosting the removal of pollutants [47]. besides increasing packing level means increasing adsorbent dosage hence more active sites with the ac are available for adsorbing more organic materials resulting in high removal of cod. the interactions among the variables are non-significant except for the highly significant double interaction of ph. in the present study, the lack-of-fit p-value (0.677 > 0.05) indicates that the lack of model fit was not statistically significant in comparison to the pure error [48]. as a result, the model can generate an adequate prediction that corresponds to the response values. the contribution of the linear term was 80.42% while the square and 2-way interactions were 15.82% and 1.35% respectively. hence the interaction effect generally is significant. ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2021) 102–112 107 3.3 the influence of process factors on the efficiency of cod removal graphical representations of rsm can be used to illustrate the interactive effects of the selected variables and their effect on the response. the figures, (4-a, b) illustrate the influence of ph on various packing levels (20% -80%) over a constant period (70 min.). the response surface plot is shown in figure 4-a, as well as the contour plot is shown in figure 4-b. the shape of the control plot indicates the nature and extent of the interactions. from the layout of the surface, it was observed that, at any ph value, as the packing level is increased from 20% to 80%, the efficiency of cod elimination increases. the increase in re% seems to be linear. a similar observation was identified by previous works [14]. this behavior is in agreement with the fact that adsorption occurs via the production of carbonoxygen surface complexes. the nature and quantity of carbon oxygen bonds are determined by the carbon surface, the oxidative treatment, the surface area, temperature, and pressure [49]. at any value of packing level, re% increases with increasing of ph 3-7 then start to be approximately constant at higher ph values. the related contour map demonstrates that the 96 percent cod removal efficiency value happened figures (5-a,b) show the impact of time on the re% for various values of packing level (20%-80%) at constant ph(5). figure 5-a demonstrates that the efficiency of cod removal increases exponentially with increasing time at low packing levels. while at a high value of packing level the effect of time is little with no significant effect. the results showed that the reaction time has a positive effect on the progress of the adsorption process only at low packing levels. this is explained by the fact that there are initially a large number of vacant surface sites accessible for adsorption. additionally, it was hypothesized that there was a strong attraction between the pollutants and the sorbent and that as contact time grew, the remaining unoccupied surface locations became harder to occupy due to saturation. this could also be a result of a shortage of suitable sorption sites after the sorption process resulting in nearly constant removal efficiency. this outcome validates by prior research [50]. the related contour map fig.(5-b) reveals that the cod removal efficiency of 96 percent is concentrated in a narrow area with packing levels ranging vinside a limited area with a ph range of 5-7 and a packing level in the range (of 60%-80%). (a) table 6. analysis of variance for cod removal. p-value f-value 𝐀𝐝𝐣. 𝐌𝐬 𝐀𝐝𝐣. 𝐬𝐬 𝐂𝐨𝐧𝐭𝐫. % 𝐒𝐞𝐪. 𝐬𝐬 𝐃𝐅 𝐒𝐨𝐮𝐫𝐜𝐞 0.002 22.54 19.8965 179.069 97.59 179.069 9 model 0.002 55.72 49.1875 147.562 80.42 147.562 3 linear 0.001 108.65 95.9112 95.911 52.27 95.911 1 (x1) 0.023 10.57 9.3312 9.331 5.09 9.331 1 (x2) 0.001 47.94 42.3200 42.320 23.06 42.320 1 (x3) 0.012 10.96 9.6748 29.025 15.82 29.025 3 square 0.238 1.80 1.5881 0.651 0.35 0.651 1 "x1 ∗ x1" 0.281 1.46 1.2889 0.535 0.29 0.535 1 "x2 ∗ x2" 0.002 31.54 27.8385 27.839 15.17 27.839 1 "x3 ∗ x3" 0.488 0.94 0.8273 2.482 1.35 2.482 3 2-way lnter. 0.186 2.35 2.0736 2.074 1.13 2.074 1 x1 ∗ x2 0.545 2.35 0.3721 0.372 0.20 0.372 1 x1 ∗ x3 0.848 0.42 0.0361 0.036 0.02 0.036 1 x2 ∗ x3 0.04 0.8827 4.414 2.41 4.414 5 error 0.677 0.6933 2.080 1.13 2.080 3 lack of fit 0.59 1.1669 2.334 1.27 2.334 2 "pure-error " 100 183.482 14 total r2(pred.) press r2(adj.) r2 s. model-summary 79.00% 93.26% 93.26% 97.59% 0.939544 108 ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2022) 102–112 (b) figure 4. impact of activated carbon ratio (packing level) and ph on the re %, (a) response surface plot, (b) contour plot. (hold values: time =70 min) (a) (b) figure 5. effect of time and activated carbon ratio on the re%, (a) response surface plot, (b) contour plot (hold value: ph =5). from 70% to 80% and time frames ranging from 60 to 80 minutes. as a result, the implementation of rsm will enable the identification of feasible optimum values for the researched parameters, as well as its function in providing valuable information about the interactions between the variables. 3.4 the optimization and confirmation test optimizing process conditions is critical and should be accomplished. numerous standards have been identified for optimizing the system by maximizing the desired function (df) by varying the importance or weight, which may alter the objective's characteristics. the variable’s target fields have five options: maximizing, objective, minimizing, within the range, and none. the target of removal of cod was selected as ‘maximum’ with corresponding ‘weight’1.0. the independent parameters examined in the study have been specified in a range of designed levels (activated carbon ratio "packing level” from (20%-80%) time: (60-80min.) and ph (3-7). the lower limit value of the efficiency of cod removal was assigned to be 87%, whereas the upper limit value was assigned to be 96.26%. the optimization procedure was carried out within those constraints and the outcomes are reported in table (7) with the function of desirability (1). two confirmatory experiments with expanded parameters were conducted to validate them; the results are shown in table (8). after 72.7 minutes of adsorption and packing at an 80 percent level, an average cod removal efficiency of 96.8 percent was obtained at ph=5.7, which is within the range of the ideal value obtained through optimization analysis using the desirability function of (1) table (7). as a result, combining the box–behnken design with the functional desirableness is effective and efficient in maximizing cod removal. table (9) compares the parameters of wastewater effluent and treated effluent based on the results of the current work in ac. as can be observed, treated wastewater has improved characteristics and conforms to the standard limitations for effluent discharge tabula (9). the present study established the efficacy of adsorption activated carbon in the treatment of wastewater generated by the al-diwaniyah petroleum refinery plant by achieving a cod removal efficiency of 96.8 percent, a phenol removal efficiency of 93.2 percent, and a turbidity removal efficiency of 95.87 percent based on the raw effluent properties. results of the present work reveal that adsorption using an activated carbon system can be applied successfully for the treatment of the al-diwaniyah petroleum refinery. starting from an initial cod of 2428 ppm, it could be achieved a cod removal efficiency of 96.70% at 73 min with a packing level of 80%. these results prove that the adsorption process absorbs the refractory natural or organic compounds that exist in petroleum refinery wastewater more proficiently. 3.5 ftir spectral analysis to investigate the effect of adsorbed organic compounds during the adsorption process in the removal of cod from petroleum refinery wastewater, the ftir spectrum was obtained for the activated carbon before and after adsorption at the optimum conditions as shown in figure 6. the ftir spectrum of material can provide valuable information about its chemical composition. during adsorption where shifting in the spectra, as well as disappearance or reduction of the peaks, can indicate the efficiency of the adsorption process[51]. ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2021) 102–112 109 . the peaks 3845.45,3830.02, 3780.07, and 3737.84cm-1are assigned to stretching vibration of the o–h bond caused by the presence of chemisorbed water and surface hydroxyl groups, which may be responsible for the organic adsorption interaction [51,52,53]. peak at 3391.07cm-1 corresponds to o-h stretches in hydroxyl, carboxylic, and phenolic groups [54]. this peak is not found in activated carbon before treatment. the peak at 3031.45 cm-1 corresponds to the aromatic c-h groups [55,51]. this peak is disappeared in the activated carbon after treatment. the peaks 2435.8, 2355.02, and 2319.4 cm-1 are assigned to c≡c stretching vibrations in alkyne groups [56, 57]. the peak at 1684.9 cm-1 is due to the c=o stretching vibrations of ketones, aldehydes, lactones, and carboxyl groups. [58, 51, 55]. this peak is not found at activated carbon before treatment. the peaks 1582.98 and 1533.14 cm-1 could be due to c=c stretching in the monosubstituted and para-disubstituted benzene rings [59, 56, 53, 57]. peaks of 1152.66 and 1185.14 cm-1 correspond to the c-o stretching vibrations in alcohols, phenols, or ether [60, 56]. finally, peak 675.89 cm-1 corresponding to c-c stretching is found in activated carbon after treatment [61]. 3.6 comparison with previous works most of the previous works were conducted at either batch or once through the continuous mode of operation. table 10 shows a comparison between our results and the results of familiar works. as can be observed, the current system performed better in terms of cod, turbidity, and phenol removal. the reason behind these results could be the higher turbulence promotion observed by using the batch recirculation mode of operation. therefore adopting batch recirculation in the removal of cod considers a promising step in the application of such a mode of operation for the treatment of different types of wastewater generated from different industrial activities. table 8: optimum of process parameters for maximum cod removal run ph packing level (%) time (min) cod (ppm) r e (%) initial final actual average 1 5.7 80 72.72 2428 80 96.70 96.69 2 5.7 80 72.72 2460 84 96.68 table 7: optimum of process parameters for maximum cod removal efficiency (re%) 𝐑𝐞𝐬𝐩𝐨𝐧𝐬𝐞 𝐆𝐨𝐚𝐥 𝐋𝐨𝐰𝐞𝐫 𝐓𝐚𝐫𝐠𝐞𝐭 𝐔𝐩𝐩𝐞𝐫 𝐖𝐞𝐢𝐠𝐡𝐭 𝐈𝐦𝐩𝐨𝐫𝐭𝐚𝐧𝐜𝐞 re (%) 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 84 maximum 96.62 1 1 solution: parameters results ph packing level (%) time (min) r e (%) fit df se fit 95% ci 95% pi 5.7 80 72.72 96.811 1 0.61 (95.244,98.377) (93.932,99.689) table 9. comparison between the wastewater effluent and the treated effluent parameter effluent cod (ppm) phenol (ppm) turbidity (ntu) so4 -2 (ppm) cl (g/l) raw effluent 2428 17.6 31.6 137 2.207 treated effluent 80(96.70%) 1.196(93.87%) 1.305(95.87%) 210 1.874 110 ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2022) 102–112 table 10. comparison of petroleum refinery wastewater treatments by ac adsorption using various mode of operation under several operating conditions 4. conclusions this study was concerned with cod removal from petroleum refinery effluent using an activated carbon-adsorption process operated in a batch recirculation mode. the response surface approach was used to conduct experiments to determine the influence of operating parameters such as packing level of activated carbon, ph, and time on the removal of cod from petroleum refinery effluent generated by the al-diwaniyah refinery plant in iraq. based on bbd, the best conditions were achieved at a packing level of 80%, a ph of 5.7, and a time of 73 minutes, in which cod removal of 96.7% was obtained. the high r2, adj.r2, and pred. r2 values indicate that the model fitted very well to the experimental data the results indicate that rsm can be successfully used to analyze the impact of various operating factors and develop the required optimum conditions thus reducing the number of runs, time, and cost of experiments. the efficiency of the activated carbonadsorption process was found to be dependent on two main parameters (packing level and ph). time was found to have the least effect. the batch recirculation mode was able to operate the system without operational problems (experimental observations), and attain good cod removal during a circulation time of 73 min. from this study, the activated carbonadsorption process seems to be an environmentally friendly process to remove cod from petroleum refinery wastewater. type of wastewater mode of operation characterization of wastewater optimum conditions efficiency ref. local petroleum refinery in uae batch cod:3490 ppm, ph=7.9 ph=6 dosage=20g/l cod%=87 [10] time =60 min. tehran refinery wastewater continuous cod:420 ppm, ph=7.9 ph=6 dosage=06.5g cod%=78 [11] flow rate= 0.185cm3/s leading refinery in s. oman batch cod:900ppm, ph=7.2 ph=6 dosage=0.6g/500ml cod%=79, [13] time(min)=120 ntu%=43of oman. tabriz refinery batch cod:622ppm, ph=7.9 ph=5.5 dosage=0.5g/100ml cod%=89.87 [14] time(min)=90 synthetic produced water batch cod:2508 ppm, ph=5.5 dosage=0.5g/100ml cod%=95.87 [15] turbidity:53ntu , ph=7 time(min)=90 ntu%=99.65 al-diwaniyah petroleum batch recirculation cod:2428 ppm, ph=5.7 packing level(%)= cod%=96.70 present work refinery wastewater turbidity:31.6ntu , ph=7.4 80time(min)=72.72 ntu%=95.87, phenol%=93.2 (a) (b) figure 6. ftir spectra of activated carbon (a) before treatment (b) after treatment ali kassob ali abbar /al-qadisiyah journal for engineering sciences 15 (2021) 102–112 111 acknowledgment the authors like to express their gratitude to the members of the chemical engineering department, college of engineering, al-qadisiyah university, for their technical assistance in completing this study. references [1] hasan db, abdul aziz ar, ashri wm, daud w. oxidative mineralization of petroleum 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[61] bakti, a. and p. gareso, characterization of active carbon prepared from coconuts shells using ftir, xrd and sem techniques. jurnal ilmiah pendidikan fisika al-biruni, 2018. 7(1): p. 33-39. https://doi.org/10.3390/en10101508 article al-qadisiyah journal for engineering sciences 13 (2020) 091–098 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7803280891 e-mail address : ali.abbar@qu.edu.iq ( ali h. abbar) https://doi.org/10.30772/qjes.v13i2.651 2411-7773/© 2019 university of al-qadisiyah. all rights reserved. removal of cadmium from simulated wastewater using rotating tubular packed bed electrochemical reactor: optimization through response surface methodology zahraa n.abbas a, ali h. abbar a* a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 17 march 2020 received in revised form 15 may 2020 accepted 27 may 2020 keywords: three-dimensional electrodes rotating cylinder electrode woven screens cadmium removal response surface methodology a b s t r a c t a rotating tubular packed bed electrochemical reactor was used for the electrochemical removal of cadmium (cd) from simulated wastewater. impacts of electrolysis operating parameters: current (0.56–2.8 a), rotation speed (100–500 rpm), initial cadmium concentration (20–100 ppm), and ph (3-9) were investigated. response surface methodology and box-behnken design were used for optimizing the process parameters where cadmium removal efficiency (re %) was selected as a response function. findings of the present work suggested that currently has a main impact on the removal efficiency of cadmium followed by rotation speed, then concentration and ph. the results of the regression analysis showed that experimental data could be fitted to a second-degree polynomial model with value of the determination coefficient (r2) equal to 91.8 %. optimal conditions for process parameters based on the rsm model were initial cd concentration of 32.0 ppm, current of 2.8 a, rotation speed of 371 rpm and ph = 3, where a final cadmium concentration less than 0.3 ppm was obtained after 30 min of electrolysis process (re= 99.28% ). © 2020 university of al-qadisiyah. all rights reserved. 1. introduction among heavy metals, cd can be considered as a very dangerous for human health, so it has been blacklisted in european society [1, 2]. cadmium is a non-essential and non-degradable mineral and hence it was considered as a major pollutant of water environments resulting in very damaging effects on life. it comes to the aquatic environment from industries such as ceramics, paper, electroplating, batteries, combustion and mining units, dyes, pvc, and many other manufacturing industries yaqub and shaikh [3]. environmental protection agency (epa) considered the chronic exposure to cadmium results in potentially poor kidney function which known as "itai-itai" disease, with symptoms prone to osteoporosis and other bone diseases [4, 5]. the regulatory restrictions for cadmium discharge to liquid wastes are very strict due to its toxicity; therefore the treatment of these liquid wastes is obligatory before they are discharged into the sewers to maintain the concentration of cadmium below the specified level barnes [6]. several conventional methods of treatment have been used to remove cadmium such as ion exchange, adsorption, reverse osmosis, chemical precipitation, biosorption, electrodialysis, ion exchange-based membrane separation, and electrochemical deposition fu and q. wang [7]. adsorption and chemical precipitation techniques suffered from a number of shortcomings caused by the high amount of http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i 92 zahraa n.abbas ana ali h. abbar /al-qadisiyah journal for engineering sciences 13 (2020 ) 091–098 chemicals used and the requirements for the sludge removal. hence, these solutions only move the problem from the liquid to the solid phase zamboulis et al. [8]. therefore, other methods should be improved to increase the demand for more competitive, economical, and effective treatment methods to remove or return metals like cadmium from industrial effluents droste et al. [9]. in latest years, electrochemical methods have received large interest because of the distinguishing features of compatibility environmental, safety, and variety. electrochemical techniques compete with other conventional technologies, like ion exchange, evaporation, solvent extraction, and precipitation. electrochemical methods are unique in their ability to recover pure metal for recycling jüttner et al. [10]. the utilizing of electrochemical techniques in environmental treatment are growing, because of the utilizing of porous materials in the design of electrochemical reactors as three dimensional electrodes. in fact, the high surface area as well as the high mass transfer rate are considered to be the major advantages of these electrodes abdel-salam et al. [11]. electrochemical methods are considered as clean, environmentally engaging technologies since the major reaction reagent is the electron. economically, the electrochemical method is valuable due to the low energy consumption compared with the well-known techniques [10]. in addition, the possibility of applying the automatization in controlling of current during the electrodeposition process results in lowering the workload requirements tonini et al. [12]. different types of "packed bed electrochemical reactors" were used to achieve the electrochemical removal of heavy metals from wastewater, such as fixed bed cathodes (flow-by and flow-through configurations) and packed bed rotating cathodes [13–18]. heavy metals removal was carried out formerly by using rotating cylinder electrodes with a packed bed in the form of woven wire meshes and reticulated vitreous carbon (rvc) [15], [19, 20]. previous studies showed that the packed bed rotating cylinder electrode of woven wire meshes when compared with other types of rotating cylinder electrodes has a value of mass transport coefficient greater approximately by three times than those observed in a smooth rotating electrode as a result of greater turbulence-promoting action of the meshes abbar et al. [19]. however, the thickness of the electrode should be kept low to ensure that the whole bed is operating under minimal current conditions kreysa and brandner [21]. yet, using the electrodes of the packed bed rotating cylinder electrode (pbrce) composed from woven wire meshes had been evidenced to be more effective than the conventional designs [15], [19]. they offer higher specific surface area which permits achieving higher removal rate of metal ion even at more dilute effluent. throughout previous studies linked to electrochemical removal of heavy metals, a traditional one-factor-at-a-time method (ofat) was commonly used. it changes just one variable at a time, while others remain unchanged. however, the interactions of the variables could not be specified by the ofat experiments. in comparison with ofat approach, a proposed method based on an experimental design approach is a more effective approach for estimating the impact of two or more variables on the response in addition to their interactions. the main advantage of an experimental design approach is requiring fewer resources (experiments, time and materials) to obtain the necessary data. in addition, the analysis of the effects of each factor is made more successful utilizing experimental design techniques cheng et al. [22]. response surface methodology (rsm) is an important subject in the statistical design of the experiments. it was successfully applied in several wastewater treatment systems, such as adsorption [23, 24], chlorine disinfection [25] , electrocoagulation [26] , fenton-related process[27] , and electrochemical oxidation [28]. rsm was widely used as an optimization system in other processes such as biofluid separation [29, 30]. it consists of a set of statistical and mathematical techniques that can be used effectively to model and analyze a variety of difficulties in which various parameters have an influence on the response of interest. the goal of rsm is to estimate the relative impact of various parameters and finally to achieve the best operating conditions by optimizing this response thirugnanasambandham et al. [31]. in our previous work, we studied the removal of copper utilizing a tubular packed bed woven screens electrode, where a good performance of this design had been reported hemeidan and abbar [32]. the main purpose of the work underway is to evaluate the efficiency of this design in the removal of cadmium by optimizing process parameters like initial metal concentration, current, rotational speed, and ph so as to achieve larger removal efficiency as possible as in cadmium removal from simulated synthetic wastewater."box-behnken design (bbd)" of the response surface methodology was adopted as an optimization technique, where no previous works have been reported on the optimization of cadmium removal using a tubular packed bed woven screens electrode. nomenclature adj. ms adjusted mean of the square adj. r2 adjusted coefficient of multiple correlation adj. ss adjusted sum of the square ai the first-class(linear) major effect aii second-class major effect aij the interaction effect anova analysis of variance ao the code of intercept bbd box–behnken design bdd boron doped diamond cd cadmium ce current efficiency (%) ci confidence interval cp reiterated number of the central point contr. percentage contribution for each parameter, % df the desirability function dof degree of freedom e voltage of cell, volt ec energy consumption, kwh / kg cd epa environmental protection agency f faraday constant, a s mol-1 i current applied, a k number of process variables n number of runs ofat one-factor-at-a-time pi prediction interval. pred. r2 predicted multiple correlation coefficient pt platinum re removal efficiency (%) rsm response surface methodology s standard error of the regression se standard error of mean seq. ss sum of square t time, s v volume of electrolyte, cm3 x1 coded value of cadmium concentration x1 concentration of cadmium, ppm x2 coded value of current x2 current, a x3 coded value of rotation speed x3 rotation speed, rpm x4 coded value of ph x4 ph y represents the dependent variable (re, %) zahraa n.abbas ana ali h. abbar /al-qadisiyah journal for engineering sciences 13 (2020 ) 091–098 93 2. experimental work the experimental runs were conducted at 0.5 l perspex-a cylindrical electrolytic cell. the working electrode (cathode) was a rotating tubular bed electrode made of 316 stainless steel woven screens wrapped around a stainless steel hollow cylinder serving as a current feeder. the hollow cylinder (current feeder) was opened at the bottom and closed at the top. it was perforated with a total of (55) holes with diameter (6mm) distributed uniformly on the lateral surface of the cylinder. the cathode feeder has an outer diameter (35 mm), inner diameter (28mm) with total length (60 mm). the lower part of this feeder is jointed with a teflon sleeve has a diameter (55 mm) and thickness ( 12 mm), whilst the upper part is joined by a teflon sleeve has a diameter (55 mm) and thickness of (17 mm) so as to fix the wrapped woven screens sheets on the current feeder. the cathode current feeder was connected to the variable speed motor shaft by means of a stainless steel rod (7 mm in diameter and 100 mm in length) mounted to the cathode feeder. the cathode has an apparent surface area (76.34 cm2) (45 mm diameter and 53 mm long). outer graphite cylinder with dimensions (90 mm inner diameter, 5 mm thickness, and 66 mm long) having a surface area of 186.92 cm2 was used as outside anode while a central graphite rod having dimensions (60 mm length and 20 mm diameter) was used as inside anode. for ensuring a uniform primary current distribution, the three electrodes (cathode, outer anode, and inside anode) were concentric in the cell body. figure 1 displays the schematic diagram of the experimental setup. figure 1. the schematic diagram for the experimental setup:1) cathode, 2) outside anode, 3) inside anode, 4) cell body, 5) jacket, 6) electrical motor, 7) power supply, 8) ammeter, 9) voltmeter, 10) water bath circulator. the cathode was cleaned with (1 m of nitric acid solution) in an ultrasound cleaner before starting any run to remove the cadmium deposits from older run, then washed with distilled water again. cadmium sulfate (3cdso4.7h2o) was used as a source of cadmium ion while sodium sulfate (na2so4) was used as a supporting electrolyte. all chemicals were of reagent grade. doubly distilled water was used for preparing electrolytic solutions containing cadmium ions dissolved in 0.5m na2so4 at concentrations (20, 60, 100 ppm). the final ph of electrolytic solutions has been adjusted by using (1m of naoh or 1m of h2so4). all runs were carried out at a fixed temperature of 25±2°c. stainless steel screens having a mesh number of 30 were used. the properties of these screens are presented in table 1. screen porosity (ε) was evaluated by determining the ratio of the weight of screen to its area (as) and applying eq. 1, then screen specific surface area(s) was computed based on eq. 2 [33]: 𝜀 = 1 − 𝑚𝑠 𝜌𝑠𝑙𝑎𝑠 (1) 𝑠 = (1 − 𝜀)𝑟 (2) where (ms/as) is the weight /area density, (r) is the" surface to volume ratio of the screen wire" equal to (4/d), (ρs) is the density of stainless steel 316-aisi equal to 8.027 gm/cm3 [34], (l) is the screen thickness equal to 2d. the woven screen type was identified utilizing olympus bx51m with dp70 digital camera system whereas a digital calliper was utilized to calculate wire diameter (d). table 1. properties of screen mesh no. (wire/inch) 30 type of woven plain square d, cm 0.030 (ms/as), g/cm 2 0.1237 𝜀 0.7146 𝑠, cm-1 38.06 removal efficiency (re, %) was determined using the following equation. [35]: 𝑅𝐸 = 𝐶𝑖−𝐶𝑓 𝐶𝑖 × 100 (3) where, cf is the final cadmium concentration after an interval of time (∆t), ci is the initial cadmium concentration. current efficiency (ce %) is the ratio of the actual mass of cadmium ion electrodeposited on the cathode surface to the theoretical mass that could be electrodeposited according to "faraday's law", it can be determined using the following equation [35]: 𝐶𝐸 = 100∗𝑧𝑖∙∗𝐹∗∆𝑚 𝑀𝑖∗ 𝐼∗∆𝑡 (4) where, i is the applied current (a); f is the faraday constant (96487a s /mol); mi is the molar mass of cadmium (112.41 g/mol); ∆m is the mass of cadmium electrodeposited at a period of electrolysis time (g); zi is the number of electrons, and ∆t is the electrolysis time (s). the major item in evaluating the cost of an electrochemical process is the specific energy required for operating the electrochemical reactor. it is defined as the energy required for the production or treatment of a certain quantity of a substance on a molar, mass, or volume basis. the energy consumption can be evaluated according to the following equation [35]: 𝐸𝐶 = 2.788×10−4𝐸𝐼∆𝑡 ∆𝑚 (5) where e is the voltage of the cell (volt). 2.1. design of experiments the relationship between both the response of process and its variables can be determined by applying a series of mathematical and statistical methods adopted by the rsm [36]. in the present study, the 4-factor 3-level “box–behnken experimental design" was used to verify and monitor the variables that affect the removal of cadmium from simulated wastewater. initial concentration of cadmium ion (x1) current (x2), rotation speed (x3), and ph (x4) were taken as process variables, whereas removal efficiency of cd (re%) was taken as a response function. the scales of process variables were coded as1 (high level), -1 (low level) and 0 (middle or central point) [37]. table 2 illustrates the process variables with their 94 zahraa n.abbas ana ali h. abbar /al-qadisiyah journal for engineering sciences 13 (2020 ) 091–098 chosen levels. box–behnken improves designs to get the suitable quadratic model with the required statistical properties by using only a part of the runs needed for a 3-level factorial. the number of runs (n) required for performing "box – behnken design" can be calculated by the following equation [38]: n =2k (k-1) + cp (6) where cp is the reiterated number of the central point and k is the number of process variables. in the present study, twenty-seven runs were performed to test the impacts of process variables on the removal efficiency of cadmium. table 3 illustrates the bbd proposed for the present research. the selected value of current in the present work was ranged from 0.56 to 2.8 a which corresponding to an anodic current density ranged from 3 to 15 ma/cm2 based on the area of the outside anode to ensure less electrical resistance due to oxygen evolution on the anode. table 2. process variables with their levels for cd removal process parameters range in box–behnken design coded levels low (-1) middle (0) high (+1) x1-concentration(ppm) 20 60 100 x2current(a) 0.56 1.68 2.8 x3-rotation speed(rpm) 100 300 500 x4-ph 3 6 9 table 3. boxbehnken experimental design blk coded value real value r u n 1x 2x 3x 4x conc. (ppm) (x1) cur. (a) (x2) rot. (rpm) (x3) ph (x4) 1 1 -1 1 0 0 20 2.8 300 6 2 1 -1 0 0 1 20 1.68 300 9 3 1 0 -1 -1 0 60 0.56 100 6 4 1 1 0 1 0 100 1.68 500 6 5 1 0 -1 1 0 60 0.56 500 6 6 1 1 1 0 0 100 2.8 300 6 7 1 1 0 -1 0 100 1.68 100 6 8 1 0 1 1 0 60 2.8 500 6 9 1 0 -1 0 -1 60 0.56 300 3 10 1 0 0 -1 -1 60 1.68 100 3 11 1 -1 0 0 -1 20 1.68 300 3 12 1 0 0 1 1 60 1.68 500 9 13 1 0 0 0 0 60 1.68 300 6 14 1 -1 0 -1 0 20 1.68 100 6 15 1 0 1 0 1 60 2.8 300 9 16 1 0 0 0 0 60 1.68 300 6 17 1 1 0 0 -1 100 1.68 300 3 18 1 -1 -1 0 0 20 0.56 300 6 19 1 0 1 0 -1 60 2.8 300 3 20 1 0 -1 0 1 60 0.56 300 9 21 1 0 0 1 -1 60 1.68 500 3 22 1 -1 0 1 0 20 1.68 500 6 23 1 1 -1 0 0 100 0.56 300 6 24 1 0 0 0 0 60 1.68 300 6 25 1 0 0 -1 1 60 1.68 100 9 26 1 1 0 0 1 100 1.68 300 9 27 1 0 1 -1 0 60 2.8 100 6 a second order polynomial model can be adopted based on bbd were fitting the interaction terms with the experimental data can be described by the following equation [39]: 𝑌 = 𝑎0 + ∑ 𝑎𝑖 𝑥𝑖 + ∑ 𝑎𝑖𝑖 𝑥𝑖 2 + ∑ 𝑎𝑖𝑗 𝑥𝑖 𝑥𝑗 (7) where, y represents the dependent variable (re), i and j are the index numbers for patterns, 𝑎0 is the intercept term, 𝑥1 , 𝑥2 … 𝑥𝑘 are the independent variables (process variables) in coded form. 𝑎𝑖 is the firstorder(linear) principal impact, 𝑎𝑖𝑖 second-order main impact and 𝑎𝑖𝑗 is the interaction impact. analysis of variance was performed then the regression coefficient (r2) was estimated to confirm the goodness of the model fit. 3. results and discussion 3.1. the analysis of statistics in this experimental program, twenty-seven statistically structured batch runs have been completed for various combinations of process parameters in order to optimize and evaluate the potential effects of independent variables on removal efficiency. table 4 displays experimental results, such as removal efficiency, energy consumption, and current efficiency at operating time of 30 min. it is shown that cadmium removal efficiency is within the range of 83-99%, while current efficiency is in the range of (0.26-5.64%) and energy consumption in the range of (963.2-30.5) kwh / kg cd. table 4. the experimental results of "box–behnken design" for the cadmium removal r u n bik conc. ppm cur. a rot. rpm ph re% e volt ce % ec (kwh/kg) act. pred. 1 1 20 2.8 300 6 99 98.4 5.3 0.26 963.2 2 1 20 1.68 300 9 93 92.4 4.9 0.41 551.9 3 1 60 0.56 100 6 84 82.6 3.3 3.46 46.6 4 1 100 1.68 500 6 92 91.3 4.3 2.10 90.6 5 1 60 0.56 500 6 94 91.8 2.9 3.87 36.0 6 1 100 2.8 300 6 97 95.6 5.3 1.32 186.1 7 1 100 1.68 100 6 87 87.8 4.3 1.96 90.6 8 1 60 2.8 500 6 98 98.2 5.7 0.81 266.9 9 1 60 0.56 300 3 90 90.2 4.3 3.73 54.9 10 1 60 1.68 100 3 93 92.5 5.4 1.27 169.3 11 1 20 1.68 300 3 97 94.7 4.7 0.43 523.7 12 1 60 1.68 500 9 94 95.0 4.7 1.29 174.9 13 1 60 1.68 300 6 92 92.3 4.4 1.27 164.0 14 1 20 1.68 100 6 88 89.3 4.5 0.39 549.7 15 1 60 2.8 300 9 98 98.8 6.3 0.81 368.7 16 1 60 1.68 300 6 92 92.3 4.3 1.27 170.9 17 1 100 1.68 300 3 93 91.8 4.5 2.10 95.0 18 1 20 0.56 300 6 85 87.5 3.3 1.13 134.3 19 1 60 2.8 300 3 99 99.7 6.4 0.82 374.6 20 1 60 0.56 300 9 87 86.6 3.3 3.59 44.2 21 1 60 1.68 500 3 93 96.2 4.9 1.28 183.5 22 1 20 1.68 500 6 96 95.4 5.1 0.43 573.1 23 1 100 0.56 300 6 83 84.7 3.6 5.64 30.5 24 1 60 1.68 300 6 92 92.3 4.4 1.27 168.6 25 1 60 1.68 100 9 91 89.3 4.5 1.25 172.4 26 1 100 1.68 300 9 89 89.7 5.3 2.02 111.7 27 1 60 2.8 100 6 97 97.9 4.9 0.8 285.0 minitab-17 software was used to analyze results of cadmium removal efficiency where an experimental relationship between cd removal efficiency and process parameters was formulated by a quadratic model as response function (re %) in terms of un-coded (real) process variable units: re% = 84.25 + 0.0789 *x1 + 5.46 *x2 + 0.0306 *x32.39 *x4 0.000779* (x1)2 + 0.362* (x2)2 0.000004* (x3)2 + 0.1171 *(x4)2 + 0.000001* x1*x2 0.000081* x1*x3 + 0.00062 *x1*x4 0.00993 *x2*x3 +0.193* x2*x4 + 0.00083 *x3*x4 (8) x1, x2, x3, and x4 are initial cd concentration, current, rotation speed, and initial ph respectively, whereas the variables x1x2, x1x3, x1x4, x2x3, x2x4, x3x4 represent the interaction effect of all the parameters of the model. (x1)2, (x2)2, (x3)2, and (x4)2 are the estimates of the zahraa n.abbas ana ali h. abbar /al-qadisiyah journal for engineering sciences 13 (2020 ) 091–098 95 principal influence of variables like initial concentration of cadmium ion, current, rotation speed, and ph. eq. (8) shows how the removal efficiency is affected by the individual variables (quadratic and linear) or double interactions. the values of positive coefficients revealed that the removal efficiency increased with the increasing of the related factors of these coefficients within the tested range while values of negative coefficients revealed the opposite effect. as can be seen, ph has a negative impact on removal performance, whereas current, rotation speed and concentration have been shown to have a positive effect. the results showed that the effects of the interactions are insignificant. bbd adequacy was identified by use variance parts complemented by specific sources of variation [40]. the adequacy of the model in anova analysis is recognized based on fisher f-test and p-test. many of the variance in response can be shown by the regression equation if the value of fisher is higher. p-value test is used to determine whether f is high enough to suggest statistical significance (90%). the percent of variability of the model could be explained if the p-value was less than 0.05 [41]. table 5 illustrates anova for the response surface model. in this table, degree of freedom (dof ), sum of square (seq. ss), percentage contribution (contr. %) for each parameter, adjusted sum of the square (adj. ss), adjusted mean of the square (adj. ms), fisher-value, and p-test value were evaluated. fisher-value of (9.59) and ptest value of (0.0001) were obtained, which illustrated the high significance of the regression model. the multiple correlation coefficient of the model was 91.80 % conforming that the regression was statistically significant and only (8.20%) of the full variations are not supported by the study. the adjusted multiple correlation coefficient (adj. r2 = 82.23 %) was compatible with r2 in this model. table 5. analysis of variance for cadmium removal p–test value fisher value adj. ms adj. ss contr. (%) seq. ss source dof 0.0001 9.59 36.349 508.884 91.80 508.884 1.model 14 0.000 30.45 115.39 461.570 83.26 461.570 linear 4 0.028 6.28 23.80 32.801 4.29 32.801 (x1) 1 0.000 93.78 355.34 355.341 64.10 355.341 (x2) 1 (x3) 1 (x4) 1 square 1 x1*x1 1 x2*x2 1 x3*x3 1 x4*x4 1 2.way int. 6 x1*x2 1 x1*x3 1 x1*x4 1 x2*x3 1 x2*x4 1 0.001 17.86 67.68 67.688 12.21 67.688 0.072 3.98 14.74 14.741 2.66 14.741 0.257 1.52 5.78 23.109 4.17 23.109 0.165 2.18 8.29 8.278 2.77 15.369 0.600 0.29 1.10 1.100 0.06 0.330 0.866 0.03 0.11 0.113 0.27 1.483 0.235 1.56 5.93 5.927 1.07 5.927 0.434 1.06 4.03 24.205 4.37 24.205 1.000 0.00 0.00 0.000 0.00 0.000 0.517 0.45 1.69 1.690 0.30 1.690 0.940 0.01 0.02 0.022 0.00 0.022 0.041 5.23 19.80 19.802 3.57 19.802 0.517 0.45 1.96 1.690 0.30 1.690 0.617 0.26 1.00 1.000 0.18 1.000 x 3*x4 1 3.79 45.470 8.20 45.470 error 12 0.003 340.83 4.54 45.443 8.20 45.443 lack 10 0.01 0.027 0.00 0.027 pure-error 2 554.354 100.00 554.354 26 total r2(adj.) r2 s. model sum. 82.23% 91.80% 1.94658 results of anova showed that the percent of contribution of the current was 64.10%. this means that the current has a major impact on the removal efficiency of cadmium (re, %). the speed of rotation, the concentration of cd, and ph have low effects based on their percentage of contribution. the linear term has the main percent of contribution in the model with 83.26 % followed by the interaction between the input variables with a contribution of 4.37%, while the square has a small contribution (4.17%). the results assure that current is the most significant factor revealing the system is under the mass transfer process. 3.2. impact of process parameters on the removal efficiency the interactive impact of the specified parameters and their effect on the response was evaluated by the graphic representation of statistical optimization utilizing rsm. figures (2-a, 2-b) show the effect of the initial concentration of cadmium on the removal efficiency of cadmium for different current values (0.56-2.8a) at constant rotation speed (300 rpm) and ph (6). figure (2-a) represents the response surface plot, while figure (2-b) shows the corresponding contour plot. from the surface plot, it was observed that, at the current of 0.56 a, the removal efficiency decreases as the initial concentration of cadmium increases. similar behavior was observed as the current increased to 2.8a. at a concentration of 20ppm, the results show that increasing of current from 0.56 to 2.8a leads to increase the cadmium removal efficiency from 85% to 99%. at a concentration of 100ppm, a similar progressive increase in the removal efficiency was observed as the current increased from 0.56 to 2.8a. the corresponding contour plot confirms that a maximum value of cadmium removal efficiency lies in a small area in which the current ranged between 2.3-2.8a and cadmium ion concentration between 20-40 ppm. the impact of ph on the removal efficiency of cadmium for different currents (0.56-2.8a) at a constant rotation speed of (300 rpm) and an initial concentration of (60 ppm) is shown in figures (3-a, 3-b). the response surface plot figure (3-a) shows that removal efficiency is slightly increased with decreasing of ph. however, at ph= 3 and current 2.8 a, a quick change in the removal efficiency was occurred reach to 98.9%, while at ph=9 and current 0.56 a the removal efficiency approached 87%. the corresponding contour plot figure (3-b) confirms that a maximum value of cadmium removal efficiency lies in a small area in which the current ranged between 2.3-2.8 a and ph 3-5.5. figures (4-a, 4-b) show the effect of rotation speed on the cadmium removal efficiency for various values of current (0.56-2.8a) at a constant concentration (60 ppm) and ph (6). figure (4-a) shows that the removal efficiency of cd is quickly increased with increasing of current from 0.56 to 2.8a at a rotation speed of 100 rpm. however, this increase became more sluggish at 500 rpm. generally, increasing of rotation speed results in increasing of removal efficiency at low current with no significant effect at higher current. the removal efficiency was increased from 84% (at rotation speed of 100 rpm and current of 0.56 a) to 98% (at rotation speed of 500 rpm & current of 2.8a). the corresponding contour plot figure (4-b) confirms that a maximum value of cadmium removal efficiency lies in a small area in which the current ranged between 2.3-2.8a and rotation speed range 300-500 rpm. it was clarified that the surface response technique not only offers additional data on the interactions between factors but also leads to the estimation of possible optimum values for the variables in the study. 96 zahraa n.abbas ana ali h. abbar /al-qadisiyah journal for engineering sciences 13 (2020 ) 091–098 (a) (b) figure 2. (a) response surface plot, (b) contour plot for the impact of initial cd concentration and current on the efficiency of cd removal( hold values: rotation speed 300rpm, ph=6) (a) (b) figure 3. (a) response surface plot, (b) contour plot displaying the impact of ph and current on cadmium ions removal efficiency (hold values: rotation speed 300rpm, cd concentration=60ppm) (a) (b) figure 4. (a) response surface plot, (b) contour plot for the effect of rotation speed and current on the cadmium removal efficiency (hold values: cd concentration=60ppm, ph=6) 3.3. the optimization and confirmation test in order to reduce the loss in energy and the cost of the treatment to a minimum value, any electrochemical removal system should be conducted to improve operational conditions to give the best possible result. standards have been established to achieve a specific goal to optimize the system by determining a specific point that improves the basic desire function (df) by regulating the weight or value that may alter the characteristics of the target. the target variable fields include five options: none, maximum, minimum, objective, and within the range. the objective of cd removal was set as maximum. the independent factors analyzed in this work were defined within the range of levels to be evaluated. (cd concentration: 20–100 ppm, current: 0.56-2.8a, rotation speed: 100-500 rpm and ph value: 3-9). the aim of electrochemical removal of cadmium is to maximize of desire function with the resulting "weight”. the value of the upper limit of removal efficacy is set at close to 99 per cent, while the lower value is allocated to 83 per cent. the optimization method has been carried out within such conditions and limits, the results are displayed in table 6. confirmative repeated experiments have been performed using optimized parameters for their validation. three experiments at the optimum values of the process parameters were performed to confirm the results of optimization tow at ph 3 and one at ph 7. the results are displayed in table 7. after 30 min of the electrolysis, removal efficiency of 99.28 % was achieved at ph=3 and 99.23% at ph=7 which are in compactable with the range of the optimum value getting from optimization analysis with desirability function of (1) (table 6). therefore, the adoption of bbd in connection with the attractiveness feature is rotation(rpm) 300 ph 6 hold values 30 06 85 90 59 30 06 09 2 1 3 59 001 %er )a(tnerruc )mpp(noitartnecnoc urface plot of re% vs current(a); concentration(ppms ) concentration(ppm) c u rr e n t( a ) 1009080706050403020 2.5 2.0 1.5 1.0 > – – – – – < 85.0 85.0 87.5 87.5 90.0 90.0 92.5 92.5 95.0 95.0 97.5 97.5 re% contour plot of re% vs current(a); concentration(ppm) concentration(ppm) 60 rotation(rpm) 300 hold values 6 85 09 59 4 6 8 2 1 8 3 59 001 %er )a(tnerruc hp urface plot of re% vs current(a); phs ph c u rr e n t( a ) 9876543 2.5 2.0 1.5 1.0 > – – – – – < 88 88 90 90 92 92 94 94 96 96 98 98 re% contour plot of re% vs current(a); ph concentration(ppm) 60 ph 6 hold values 502 400 85 90 1 95 100 502 400 550 2 1 3 95 100 %er )a(tnerruc )mpr(noitator urface plot of re% vs c )rrent(a); rotation(rpms u rotation(rpm) c u rr e n t( a ) 500400300200100 2.5 2.0 1.5 1.0 > – – – – – < 85.0 85.0 87.5 87.5 90.0 90.0 92.5 92.5 95.0 95.0 97.5 97.5 re% contour plot of re% vs current(a); rotation(rpm) zahraa n.abbas ana ali h. abbar /al-qadisiyah journal for engineering sciences 13 (2020 ) 091–098 97 effective and efficient in optimizing the removal of cadmium by using (pbrce). table 6. optimum of process parameters for the maximum removal efficiency of cadmium table 7. confirmative value for optimum removal efficiency ec kwh/ kg ce (%) r e(%) at 30 min e volt ph conc. ppm rot. rpm cur a run avg. act. 553 0.44 99.28 99.26 5.01 3 32.0 371 2.8 1 99.3 5.12 3 32.0 371 2.8 2 555 0.43 99.23 99.23 5.08 7 32.0 371 2.8 3 3.4. comparison with previous works rotating cylinder electrode of wedge wire screens used for electrochemical removal of cadmium from dilute aqueous solutions has been investigated by grau and bisang [42]. in their work, the effects of applied cathodic potential and screen size on the removal of cadmium were analyzed. cathode potential of -1.1 v versus standard calomel electrode (sce) at (700 rpm) has been applied and taken to be the better value for decreasing cd concentration from 54 to 0.9 ppm at the end of 30 minutes of electrolysis with a specific power consumption of 10.7 kwh/ kg and a space velocity of 3.54 1/ h. in the present work, the removal level of cadmium was similar to that obtained by grau and bisang[42] but starting with lower initial concentration of cadmium (32.0 ppm) at the same time interval (30min) under glavanostatic conditions (constant current not electrode potential). this is an indication of the good performance of the present rotating cylinder electrode since glavoanostatic operation mode is the preferred mode on the industrial scale. the very low current efficiency that was obtained in the present work (0.44 %, table 7) means that most of the current is consumed for hydrogen evolution as a side reaction. this lower current efficiency is expected since the concentration of cadmium is very low (32.0 ppm), and ph of the solution is 3. the same observations with respect of lower current efficiency was observed by reade et al. [43] in their work for cadmium removal using (rvc) rotating cylinder electrode from a solution with the initial concentration of cadmium (56 ppm) in deoxygenated na2so4 at ph 2. they found that when the concentration of cadmium declined to less than 1 ppm from an initial concentration of 56 ppm, the current efficiency declined from 75 % rapidly to reach 20 % as cd concentration reached to 3 ppm and then declined further with decreasing the concentration. the new rotating cylinder electrode used in this study showed very satisfactory performance in the removal of cadmium, although the literature reported some values of the current efficiency higher than those in the glavoanostatic process. however, an additional gain can be obtained from the present work by using hydrogen as a chemical source for other industrial applications when a divided cell design is adopted on the industrial scale. 4. conclusions high removal efficiency of cadmium from simulated wastewater solution was achieved successfully in the present work by using a rotating tubular packing bed of a woven screen electrode as cathode in a batch electrochemical reactor. the rsm “box-behnken “concept has proven to be a very efficient and accurate methodology for optimizing cadmium electrochemical removal. analysis of anova displayed a high value of r2 (0.918) as a correlation analysis coefficient indicating good agreement between the quadratic model and experimental results. the present results have shown that the current has the main significant effect on the removal efficiency confirming that the electrodeposition reaction is under mass transfer control. optimum conditions for the process factors were 2.8a as current, 371 rpm as rotation speed, 32.0 ppm as initial cadmium concentration, and ph of 3. under these conditions, the concentration of cadmium was decreased from 32.0 ppm to less than 0.3 ppm (re= 99.28 %) in a matter of 30 min while full removal of cd was accomplished at 45 min, hence another benefit offered by the present system in term of its ability to complete removal or recover of cadmium from wastewater. acknowledgment the researchers wish to acknowledge the beneficial and technical assistance received by the staff and technicians at the department of chemical engineering, faculty of engineering-university of al-qadisiyah. references [1] a. corami, s. mignardi, and v. ferrini, cadmium removal from singleand multi-metal (cd+ pb+ zn+ cu) solutions by sorption on hydroxyapatite, journal of colloid and interface science, 317(2) (2008) 402–408. 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[43] g. w. reade, p. bond, c. ponce de leon, and f. c. walsh, the application of reticulated vitreous carbon rotating cylinder electrodes to the removal of cadmium and copper ions from solution, journal of chemical technology and biotechnology, 79(9) (2004) 946–953. article al-qadisiyah journal for engineering sciences 14 (2022) 162–169 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: abbas.shuaab@qu.edu.iq (abbas khalaf ) https://doi.org/10.30772/qjes.v14i3.777 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. treatment of oily wastewater by using polysulfide polymer fatima mohammed taha, abbas khalaf mohammad *, nawras s. sabeeh chemical engineering department, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 3 august 2021 received in revised form 11 december 2021 accepted 19 december 2021 keywords: oily wastewater polymer sustainable material adsoption a b s t r a c t the discharge of water from oil fields is become one of the most significant environmental concerns associated with the oil sector. this study features a low-density polysulfide polymer prepared by sulfur and used sunflower oils react directly. because both sulfur and cooking oils are hydrophobic, the polymer can easily extract hydrocarbons like crude oil and diesel fuel from saltwater. sulfur is a petroleum industry byproduct, and leftover sunflower oil may be utilized as a raw material. 150 g food-grade used sunflower oil, 150 g sulfur, and 700 g finely powdered sodium chloride were used in an experiment to make polysulfide. the reaction temperature was adjusted at 180°c. the resulting polymer (a soft rubber) is friable; therefore, it was ground down using a mechanical grinder and screened for particles between 0.5 and 3 mm. the polymer was repeatedly rinsed with di water to eliminate the sodium chloride porogen. the polymer was filtered through a sieve (0.5 mm) and pressed with a piece of flat plastic to remove surplus water after the final wash. the polymer was then dried in a sieve by putting it in a drying oven (unb400, germany) for 24 hours at 42 degrees celsius. kinetics of adsorption was examined with pseudo−first order, pseudo−second order and intra particle diffusion models. the experimental results show good fitting with pseudo−second order model for south oil adsorption on polysulfide polymer. adsorption of north and south oils onto the prepared polysulfide polymer was done experimentally using batch apparatus with controlled conditions of temperature and stirring. effects of temperature and initial oil concentration for the adsorption process were examined for the ranges (20−40) ◦c and (10−90) (g/l), respectively. the experimental data follows the freundlich isotherm model with coefficient of variance (r2) equals, according to the study of adsorption equilibrium isotherms (0.99). according to the findings of the study, the greatest g/l of south oil removal equals 93 percent at the lowest temperature of 20 degrees celsius. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction various pollutants are emerging in our environment. one of the pollutants that can cause an environmental problem is the present of oil and grease inside water system[1] and [2]. when petroleum wastewater is introduced into the aquatic environment at high concentrations, it becomes toxic to aquatic organisms and damages other ecosystems in the body of water abdul hamid et al. [3].oily wastewater discharge into natural water streams has risen as a result of industrial growth and human activities. crude oil spills, power plants, extraction of crude oil, stations, petrochemical plants, and domestic trash such as spent cooking oil and lubricant from vehicle spills are all sources of oily wastewater. crude oil transportation is another source of oil spills in surface water singh et al. [4]. oil and grease may be removed from wastewater using a variety of procedures, which are chosen depending on the effluent's qualities and condition. some of the most common methods for treating oily wastewater include gravity, floating, chemical and biological treatment, and dissolved air flotation. these solutions, on the other hand, came at a great price and required constant upkeep. another option is de-emulsification, although it’s not frequently utilized due to its low removal efficiency and expensive [3]. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 163 fatima mohammed taha et al. /al-qadisiyah journal for engineering sciences 14 (2021) 000–000 various research has been done in order to determine the best methods for removing oil from water. oil removal procedures include adsorption, flotation, coalescences, membrane filtration, biological treatment, electrocoagulation, coagulation, and flocculation. each approach has its own set of benefits and drawbacks. one of the most popular ways for eliminating pollutants is adsorption, which is one of the methods described above. the advantages of employing adsorption techniques, according to earlier studies, include high oil removal efficiency, cheap cost, and low processing cost [3]. 2. experimental work all chemicals that were used with in experiment are of high purity and analytical grades, except for the oil that was supplied from al shanafiya refinery in al-diwaniyah province . table 1. shows the properties of south oil. properties south crude oil api 29.3 salt 133.2 sp . gr 0.87997 w & s 0.075 source shenafia refinery 2.1 polysulfide polymer preparation apparatus as shown in fig. 1, the 4.7l stainless steel cylindrical reaction vessel with 20 cm internal diameter was placed on a therostated hot plate, to restrict heat loss from the reaction vessel to the environment, a covering of glass wool was placed on top of it. to collect and discharge reaction gases to a safe location, the whole reaction equipment was constructed under a fume hood. an h-frame platform was used to secure an overhead electrically powered mechanical stirrer (ls-50d, korea). an impeller made of stainless steel (15 cm square blade) was positioned in the reaction vessel's middle to get the necessary power for actively mixing the reaction mixture. tie cables were used to hold the reactor to the h-frame support. the temperature probe and the large glass funnel were fastened to avoid contact with the reaction vessel's whirling impeller, which was three millimeters from the bottom. after filtering the samples of each run, the cod value was calculated to assess the process' performance. all of the trials were repeated three times and only the average values were taken. figure 1. (1) stainless steel reaction vessel; (2) glass wool; (3) electrically drive mechanical stirrer; (4) stainless steel impeller; (5) hotplate equipped with temperature probe; (6) glass funnel; (7) digital thermometer; 8, 9, and 10. the h-frame stand with cable ties. 2.2 apparatus used for adsorption process. based on the study [3],[4],[5],[6],[7] and [8] a 500 ml three nick conical flask (goel, germany) was used as an adsorption chamber. the adsorption temperature was measured and recorded using a glass thermometer submerged within the flask. the flask was equipped with pyrex glass recycling condenser to ensure retarding of any vapors from adsorption mixture. 1000 ml pyrex glass beaker (simax, germany) covered via a layer of glass wool insulation material was used as a water bath for the adsorption mixture. a thermo couple connected to a digital recorder was put inside the beaker for continuous monitoring of water bath temperature. the whole adsorption equipment was put over a hot plate magnetic stirrer (sh-2, germany) for supplying necessary heat required for the water bath as well as providing the vigorous mixing of adsorption mixture. based on the study [3],[4],[5],[6],[7] and [8] a 500 ml three nick conical flask (goel, germany) was used as an adsorption chamber. the adsorption temperature was measured and recorded using a glass thermometer submerged within the flask. the flask was equipped with pyrex glass recycling condenser to ensure retarding of any vapors from adsorption mixture. 1000 ml pyrex glass beaker (simax, germany) covered via a layer of glass wool insulation material was used as a water bath for the adsorption mixture. a thermo couple connected to a digital recorder was put inside the beaker for continuous monitoring of water bath temperature. the whole adsorption equipment was put over a hot plate magnetic stirrer (sh-2, germany) for supplying necessary heat required for the water bath as well as providing the vigorous mixing of adsorption mixture. nomenclature api american petroleum institute qt kinetic adsorption capacity (g/g) sp . gr specific gravity temp. temperature w & s water and sediment conc. concentration ce concentration of adsorbate solution uv-vis uv/visible spectroscopy g gram c celsius degree qe adsorption capacity (g/g) 164 fatima mohammed taha et al. /al-qadisiyah journal for engineering sciences 14 (2022) 162–168 figure 2. (1) three nick conical flask; (2) pyrex glass beaker; (3) glass wool insulation material; (4) hot plate magnetic stirrer; (5) pyrex glass recycling condenser; (6) glass thermometer; (7) digital thermometer; (8 and 9) the h-frame stand with cable ties 2.3 polysulfide polymer preparation procedure in the reaction vessel, 150 g of food-grade used cooking oil was added. the oil was heated to 170 °c and the overhead stirrer was turned on at 100 rpm. the temperature of the oil was immediately measured using a temperature probe and a digital recorder. (150.0 grams) sulfur was then introduced via the funnel at a pace that kept the temperature of the reaction mixture above 155 °c. the sulfur was added over the course of about 10 minutes. a red bottom layer is formed by molten sulfur and sulfur prepolymers from ring-opening polymerization, whereas a light top layer is formed by the oil. the two phases begin to interact positively at this scale. at this size, the two phases begin to react, resulting in an opaque mixture over the course of the sulfur addition. the sodium chloride porogen was added once the reaction liquid was opaque and two separate layers were no longer visible. as a result, sodium chloride (700g, finely powdered in a blender) was poured via the funnel at a pace that kept the temperature of the reaction mixture above 155 c. at compensate for the internal temperature drop, the reaction temperature was adjusted to 180°c when the sodium chloride was added. the whole amount of sodium chloride was added over the course of 20 minutes. the reaction mixture was often an orange, opaque, and somewhat free flowing slurry when the salt was added. the mixture thickens and darkens to a brown tint when it is heated at 180°c. when the viscosity reaches a threshold where the overhead stirrer reports a torque of 40 an• cm, the reaction is stopped. this alteration happened 15 minutes after the sodium chloride addition was completed. some gases (h2s) may be produced at this step of the process, hence working under a fume hood is required. because overheating or extended heating at 180 c causes further gas evolution, the reaction was stopped as soon as the stirrer torque reached 40an •cm. to halt the reaction, disconnect the stirrer and hotplate from the power source, cut the cable connections, remove the hot plate, and set the reaction vessel on a trivet to prevent additional heating. the resulting polymer (a soft rubber) is friable, allowing the impeller to be easily removed with a spatula. with a big spatula, the polymer was broken into large bits and removed from the reaction tank. after that, the polymer was ground with a mechanical grinder and screened for particles between 0.5 and 3 mm. the screening analysis equipment used to sift the polymer particles is shown in fig. 3. to remove the sodium chloride porogen, the polymer was repeatedly washed with di water. a 200rpm overhead stirrer was used to agitate the mixture for 30 minutes. the polymer was then extracted using a sieve machine (fritch, germany) and washed three times in the same manner. the polymer was then dried in the sieve by placing it in a drying oven at 42 degrees celsius for 24 hours. worthington et al. (worthington et al., 2018). fig. 3 depicts the procedures for making polymer. figure 3. photographic picture of the steps of preparation of polymer. a. the polymer was broken into large spatula; b. the polymer was rinsed in di water many times; c. a mechanical mill was used to grind the polymer into particles ranging in size from 0.5 to 3 mm; d. the produced polymer was dried in the sieve by putting the material in drying oven at 42oc. 3. results and discussion 3.1. equilibrium of adsorption isothermal information analysis with the application of characteristic isothermal modeling is a major development in determining the appropriate model that can be used for design purposes. as a result, the relationship of equilibrium data that uses either a theoretical or experimental formula to understand and predict the degree of adsorption, in choosing the most extreme adsorption limit for a given adsorbent [9],[10],[11],[12],[13]and [14] figure 4 represent the equilibrium adsorption isotherms curves for the south oil on the surface of the prepared polysulfide adsorbent. these curves were plotted for the range of concentration (0-60) g/l at various temperatures (20, 25, 30, 35, and 40 ° c). it could be recognized from these figure that there is a proportional relationship between the concentration of oils in the solution and its concentration in the adsorbed phase. this is clearly shown from the shape curves of isotherms that are of classical adsorption type. this means that any increasing of concentration of oil in the solution increases the concentration of oil on the surface of the adsorbent. but this proportionality becomes less notable at high concentrations of oils in the solution because the adsorbent reaches its maximum capacity. the values of maximum capacities for the prepared polysulfide are shown in table (2). table 1. polysulfide maximum capacities for south crude oil. temp. c ce (g/l) qe (g/g) 20 0.12 1.65 25 0.2 1.56 30 0.3 1.47 35 0.4 1.4 40 0.5 1.32 a b c d fatima mohammed taha et al. /al-qadisiyah journal for engineering sciences 14 (2022) 162–168 165 figure 4. adsorption equilibrium isotherms for south oil adsorbed on the polysulfide polymer at different temperatures. it could be recognized from these figures that there is a proportional relationship between the concentration of oils in the solution and its concentration in the adsorbed phase. this is clearly shown from the shape of isotherms curves that are of classical adsorption type. this means that any increasing of concentration of oil in the solution increases the concentration of oil on the surface of the adsorbent. but this proportionality becomes less notable at high concentrations of oils in the solution because the adsorbent reaches its maximum capacity. 3.2 effect of temperature the temperature range for the adsorption process was chosen from 20o c up to 40oc in viewing to the expected values for the industrial process. it was clearly observed from these figures that an increase of temperature causes a decrease in the adsorption capacity for the two oils. this result agrees with previous study which was done by (yagub et al). figure 4 shows the effect of temperature on the removal percentage of oils. these figures indicate that the increasing of temperature leads to a decreasing of the removal percentage of the two oils. where, the removal percentage of south oil decreased from 93% to 75% with the same increasing of temperature. this behavior is in agreement with the study done by worthington et al.[15]. they explained that the adsorption forces between the adsorbed molecules and the active sites become weak when the temperature increases, which leads to a decrease in the removal percentage of oil. 3.3 formulation of adsorption equilibrium the experimental adsorption data of south crude oil onto prepared polysulfide polymer were correlated using langmuir and freundlich adsorption isotherm models. these equations were chosen in this work because they are the most well-known equations for the adsorption of a pollutant in aqueous solution onto a solid adsorbent (dada et al., 2012). langmuir adsorption isotherm represents the adsorption of solute that limits to a single monolayer of solute molecules on the solid adsorbent. this is based on the langmuir theory of adsorption which assumes the surface of the solid adsorbent as a homogeneous surface. however, langmuir adsorption isotherm equation could be represented mathematically as (wang et al., 2010): 𝑞𝑒 = 𝑄𝑚 𝑏 ∗ 𝑐𝑒/(1 + 𝑏 𝑐𝑒) (1) where: ce: equilibrium concentration of the oil in the liquid phase (g/l). qe: equilibrium concentration of the oil in the solid phase (g/g). b: constant of the langmuir adsorption (l/g). qm: langmuir maximum uptake of the oil (g/g). freundlich adsorption isotherm represents the adsorption of solute as a multilayer of molecules onto the heterogeneous surface of solid adsorbent. freundlich adsorption isotherm equation could be represented mathematically as (dada et al., 2012): 𝑞𝑒 = 𝑘𝑓 𝑐𝑒1/n (2) where: kf : constant of freundlich isotherm . n : intensity of adsorption . langmuir and freundlich adsorption isotherm equations were expressed in linear forms and respectively as follow: 𝑐𝑒/𝑞𝑒 = 1/(𝑄𝑚 𝑏) + 1/𝑄𝑚 ∗ 𝐶𝑒 (3) log 𝑞𝑒 = log 𝐾𝑓 + 1/n log 𝐶𝑒 (4) the experimental data for adsorption of south crude oil on the prepared polysulfide were correlated with the linearized form of langmuir and freundlich adsorption equations and shown in figs. (5-6). it was clearly observed from these figures that the experimental data corresponding the freundlich isotherm very well. this result indicates that the adsorption of south oil and north oil onto the polysulfide polymer was occurred on heterogeneous surface and multilayered. figure 5. linearized form of freundlich isotherm model for south oil adsorbed on polysulfide at different temperatures. figure 6. linearized form of langmuir isotherm model for south oil adsorbed on polysulfide at different temperatures. 0 2 4 6 8 0 10 20 30 40 50 q e ( g /g ) ce (q/l) 20 c 25 c 30 c 35 c 40 c 0 0.2 0.4 0.6 0.8 1 0 0.5 1 1.5 2 lo g q e log ce 20 c 25 c 30 c 35 c 40 c 0 4 8 12 16 0 10 20 30 40 50 ce /q e ( g /l ) ce (g/l) 20 c 25 c 30 c 35 c 40 c 166 fatima mohammed taha et al. /al-qadisiyah journal for engineering sciences 14 (2022) 162–168 this congruence with freundlich isotherm could be clearly evident by recognizing the values of confidence level (r2). table 3 show the comparison between the langmuir and freundlich isotherms for south oils equilibrium adsorption data. table 3. isotherm parameters for south oil at temperature range (20– 40) ◦c. temp langmuir model freundlich model ℃ qm (g/g) p (1/g) r2 kf n r2 20 25 30 35 40 1.6000 1.5500 1.4959 1.4080 1.3000 0.060 0.066 0.050 0.047 0.042 0.8160 0.8691 0.9287 0.9201 0.8115 0.5680 0.4650 0.3540 0.2980 0.1904 1.129 1.715 0.974 1.169 0.914 0.9868 0.9701 0.9696 0.9754 0.9729 3.4 kinetic of adsorption the quantity of south oil adsorbed on the produced polysulfide as a function of time for the temperature range (20–40) c is shown in fig. 7. the amount of oil adsorbed grows fast in the first sixty minutes, as seen by these data. after that, until the equilibrium state is reached, there is no substantial variation in the quantity adsorbed figure 7. adsorption rate of south oil on polysulfide at various temperatures. these figures show that the rate of adsorption of oil on the polysulfide polymer (slope of curves) is high at initial period and approaches zero at late times. this is due to the decreasing of adsorption driving force which is the oil concentration in solution minus its concentration on the surface of adsorbent. pseudo−first order, pseudo−second order and intra particle diffusion kinetics adsorption models were used to correlate the experimental adsorption data of the present study. these kinetics models could be expressed mathematically as (onal, 2007): first order: 𝑑𝑞𝑡 𝑑𝑡 = 𝑘1 ∗ (𝑞𝑒 − 𝑞𝑡) (5) second order: 𝑑𝑞𝑡 𝑑𝑡 = 𝑘2 ∗ (𝑞𝑒 − 𝑞𝑡)2 (6) intra particle model : 𝑑𝑞𝑡 𝑑𝑡 = 1 2 𝑘𝑖𝑛𝑡 ∗ 𝑡 −0.5 (7) where: qt: adsorption capacity at time t (g/g). k1: the rate constant of pseudo first order kinetic model (l/min). k2: the rate constant of pseudo-second order kinetic model (g/g. min). kint: the intra particle diffusion rate constant ((g/g. min^1/2)). the previous mentioned adsorption kinetic models were integrated to obtain the following formulas: 𝐥𝐨𝐠(𝒒𝒆 − 𝒒𝒕) = 𝐥𝐨𝐠 𝒒𝒆 − 𝒌𝟏 𝟐.𝟑𝟎𝟑 ∗ 𝒕 (8) 𝒕 𝒒𝒕 = 𝟏 𝒌𝟐 𝒒𝒕𝟐 + 𝟏 𝒒𝒆 ∗ 𝒕 (9) 𝒒𝒕 = 𝒌𝒊𝒏𝒕 ∗ 𝒕𝟎.𝟓 + 𝑪 (10) where c is constant. figures 8 and 9 shows the kinetics experimental data fitting with linearized form of pseudo−first order, pseudo−second order and intra particle diffusion kinetics models for south oil and north oil adsorption on polysulfide polymer. it was clearly observed from these figures that the pseudo−first order and intra particle diffusion kinetics models not corresponding with the experimental rate of adsorption data. it also could be recognized that the second−order kinetic model represents the experimental rate of adsorption data well. figure 8. pseudo first order kinetic model for adsorption south oil on polysulfide at different temperatures. figure 9. pseudo second order kinetic model for adsorption of south oil on polysulfide at different temperatures. 0 0.4 0.8 1.2 1.6 2 0 50 100 150 200 250 q t (g /g ) t (min) 20 c 25 c 30 c 35 c 40 c -2 -1.5 -1 -0.5 0 0.5 1 1.5 0 100 200 300 lo g (q e -q t) t (min) 20 c 25 c 30 c 35 c 40 c 0 50 100 150 200 0 100 200 300 t/ q t (m in /g /g ) t (min) 20 c 25 c 30 c 35 c 40 c fatima mohammed taha et al. /al-qadisiyah journal for engineering sciences 14 (2022) 162–168 167 table 4. pseudo first order and second order parameters of the adsorption process in south oils at different temperatures. temp first order second order ℃ qe cal. (g/g) k1 ( 1 𝑚𝑖𝑛 ) r2 qe cal. (g/g) k2 ( 1 𝑚𝑖𝑛 ) r2 20 25 30 35 40 0.351 0.239 0.196 0.185 0.108 0.175 0.017 0.017 0.018 0.017 0.735 0.730 0.707 0.716 0.706 1.65 1.56 1.47 1.40 1.32 0.187 0.340 0.230 0.196 0.159 0.999 0.996 0.999 0.999 0.999 3.5 effect of initial concentration figure 10. removal percentage of south oil for different initial concentration at 20 ◦c and contact time 4 hrs. figure 11. removal percentage of south oil for different initial concentration at 25 ◦c and contact time 4 hrs. figure 12. removal percentage of south oil for different initial concentration at 30 ◦c and contact time 4 hrs. figure 13. removal percentage of south oil for different initial concentration at 35 ◦c and contact time 4 hrs. figure 14. removal percentage of south oil for different initial concentration at 40 ◦c and contact time 4 hrs. it was clearly shown from these figures that an increasing of the initial concentration of the two oils in the solution associated with a decreasing of the removal percentage. however, the increase of initial concentration enhances the adsorption capacity but diminishes the removal percentage of oil. this clearly observed from figs. (10−14), where the removal percentage at 20 ◦c decreased from 93% to 69.32% for south oil corresponding to an increase of initial concentration from 10 to 90(g/l). this behavior agrees with study done by (foo & hameed, 2010). this behavior may be explained as follows. in most cases of low concentrations of oils in solution, the ratio of the initial number of oil molecules to the available surface area is low hence, the partial adsorption is independent on the concentrations while at high concentrations of oils in solution, the available adsorption sites become less as a result of reaching the adsorption sites to the saturation state. 4. conclusions the present study shows that the polysulfide polymer gives high ability in removal of south crude oil from aqueous solution. this work concludes on a variety of important points: 1. ftir spectra has showed the chemical structure of polysulfide polymer, the result expresses different functional groups (c-h, c=o and c-s) distributed on the surface that indicate the success of the preparation process. 2. the equilibrium adsorption isotherm that was applied on the experimental data showed that the freundlich isotherm fitted well the experimental adsorption data with confidence level 0.99. 0 20 40 60 80 100 0 20 40 60 80 100 r e m o v a l o f o il , % initial concentration (g/l) 0 20 40 60 80 100 0 20 40 60 80 100 r e m o v a l o f o il , % initial concentration (g/l) 0 20 40 60 80 100 0 20 40 60 80 100 r e m o v a l o f o il , % initial concentration (g/l) 0 20 40 60 80 100 0 20 40 60 80 100 r e m o v a l o f o il , % initial concentration (g/l) 0 20 40 60 80 100 0 20 40 60 80 100 r e m o v a l o f o il , % initial concentraction (g/l) 168 fatima mohammed taha et al. /al-qadisiyah journal for engineering sciences 14 (2022) 162–168 3. polysulfide polymer was very effective in removing oils, where the maximum percentages removal south oil equals to 93%. 4. kinetics of adsorption give an idea about the rate of adsorption for north oil and south oil, it was clearly observed that the pseudo−second order model corresponded with the experimental data with confidence level equals to 0.999. 5. recommendations 1-studying other parameters effecting on the adsorption capacity such as dosage, ph and contact time. 2choosing another type of cooking oil in prepared polysulfide polymer. acknowledgment the authors wish to thank all staff of chemical engineering department, college of engineeringal-qadisiyah university for their technical support to achieve the present work. references [1] o. bridges, “double trouble: health risks of accidental sewage release,” chemosphere, vol. 52, no. 9, pp. 1373–1379, 2003, doi: 10.1016/s00456535(03)00472-7. [2] m. fingas, the basics of oil spill cleanup. crc press, 2012. [3] n. s. abdul hamid, n. a. che malek, h. mokhtar, w. s. mazlan, and r. mohd tajuddin, “removal of oil and grease from wastewater using natural adsorbents,” j. teknol., vol. 78, no. 5–3, pp. 97–102, 2016, doi: 10.11113/jt.v78.8519. [4] h. singh, a. jain, j. kaur, s. k. arya, and m. khatri, “adsorptive removal of oil from water using spions–chitosan nanocomposite: kinetics and process optimization,” appl. nanosci., vol. 10, no. 4, pp. 1281–1295, 2020, doi: 10.1007/s13204-019-01195-y. [5] e. worch, adsorption technology in water treatment. 2012. [6] c.-i. lin and l.-h. wang, “rate equations and isotherms for two adsorption models,” j. chinese inst. chem. eng., vol. 39, no. 6, pp. 579–585, 2008. [7] m. ungarish and c. aharoni, “kinetics of chemisorption. deducing kinetic laws from experimental data,” j. chem. soc. faraday trans. 1 phys. chem. condens. phases, vol. 77, no. 5, pp. 975–985, 1981. [8] s. w. nam, d. j. choi, s. k. kim, n. her, and k. d. zoh, “adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon,” j. hazard. mater., vol. 270, pp. 144–152, 2014, doi: 10.1016/j.jhazmat.2014.01.037. [9] s. j. kulkarni, “role of adsorption in petroleum industries and refineries,” int. j. pet. petrochemical eng., vol. 2, no. 1, pp. 16–19, 2016, doi: 10.20431/2454-7980.0201004. [10] c. franco, m. martínez, p. benjumea, e. patiño, and f. cortés, “water remediation based on oil adsorption using nanosilicates functionalized with a petroleum vacuum residue,” adsorpt. sci. technol., vol. 32, no. 2–3, pp. 197– 207, 2014, doi: 10.1260/0263-6174.32.2-3.197. [11] w. rudzinski and w. plazinski, “kinetics of solute adsorption at solid/solution interfaces: a theoretical development of the empirical pseudo-first and pseudo-second order kinetic rate equations, based on applying the statistical rate theory of interfacial transport,” j. phys. chem. b, vol. 110, no. 33, pp. 16514–16525, 2006, doi: 10.1021/jp061779n. [12] p. wisner, k. heimlich, and l. gervais, “survey of oil water separators and drainage design aspects at transformer stations,” in global solutions for urban drainage, 2002, pp. 1–13. [13] j. idris, u. teknologi, and j. idris, “oil spills and sustainable cleanup approach,” aust. j. basic appl. sci., no. march, pp. 272–280, 2013. [14] s. sen gupta and k. g. bhattacharyya, “kinetics of adsorption of metal ions on inorganic materials: a review,” adv. colloid interface sci., vol. 162, no. 1–2, pp. 39–58, 2011, doi: 10.1016/j.cis.2010.12.004. [15] m. j. h. worthington et al., “sustainable polysulfides for oil spill remediation: repurposing industrial waste for environmental benefit,” adv. sustain. syst., vol. 2, no. 6, pp. 1–7, 2018, doi: 10.1002/adsu.201800024. article al-qadisiyah journalforengineering sciences14 (2021) 062–065 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ozeairabessi@gmail.com (dr. ozeairabessi) e-mail address: mukhtardhajir@gmail.com (mukhtar dh. abbas) https://doi.org/10.30772/qjes.v14i1.742 2411-7773/©2021university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. environmental impact evaluation of brick factories on west of aldiwaneyha city _iraq ozeair abessi a, mukhtar dh. abbas a,b* a babol noshirvani university of technology, iran. b ministry of environment, al-qadissiyah environment directorate, aldiwaneyah – iraq. a r t i c l e i n f o article history: received 6 april 2021 received in revised form 16 may 2021 accepted 23 may 2021 keywords: air pollution, brick factories, environmental legislations, impact assessment. a b s t r a c t the objective of this study is to evaluate the environmental impact of a brick factory complex in the west part of al-diwaneyah city. in the study, the site characteristics of the brick factories and compares them with the locational determinants in the iraqi environmental laws were assessed. the arc.gis software has used to process the spatial data and displays. the spatial analysis show that the current site of brick factories does not conform to the current laws and regulations of iraq. so, it eventually will create environmental problem to the city's expansion or factories development. furthermore, air quality in the west of city has measured in some monitoring sites along the direction of wind, close to the brick factories. the gases concentration measurement has continued for 12 days and24 hours per day in the monitoring sites.so2, no2, co and nmhc were measured which showed that the maximum values of so2, no2 and nmhc were higher than iraqi standard while the co value was very low. ©2021university of al-qadisiyah. all rights reserved. 1. introduction the environment consists of two series of factors, the biotic (microorganisms and living organisms) and abiotic factors (atmosphere, hydrosphere, and lithosphere). the pollution is the presence of energy or substances in the form that be harmful for humans and other living organisms. so, the pollutants can be any dangerous solids, liquids, or gases substances that has higher quantities than usual that inversely affected the environment. manisalidis et al. [1]. contaminated sites can be defined as “areas include human activities which have discharged or might discharge contaminants into soil, air, surface or groundwater, food-chain, causing or being able to cause impacts in human health” drago et al. [2]. the clay brick manufacturing is one of the ancient traditional industries which widespread in the most regions of iraq and are the most polluting source to the surrounding environment where the used fuel in brick kilns operating is residual fuel oil that remains after the distillate fuel oil and lighter hydrocarbons are distilled away in refinery operations. iraqi environmental determinants instructions of the projects establishment and monitoring the safety of their implementation no. (3) for the year 2011specified that the brick factories must be far (5 kilometers) from both the cities municipalities borders and residential communities which more than (20 houses) and also must be far (1 kilometer) from roads.[3] brick's manufacturing has a negative impact on the natural and human atmosphere as a result of the pollution which has been caused from gasses, smoke, and mist al-khateeb et al. [4]. the most pollutants that have been discharged from the brick kilns are particulate matters, (vocs), sox, dioxins, (pahs) and nox [1] and are the essential sources of air pollutants and harmful to humans misra et al. [5]. where the contaminated industrial sites are responsible for outdoor air pollution which contribute in deaths more than four million premature worldwide perrino c et al. [6]. studied the relationship of the exposure impact to http://qu.edu.iq/ mailto:mukhtardhajir@gmail.com https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ ozeair abessi , mukhtar dh. abbas /al-qadisiyah journalfor engineering sciences 14 (2021) 062–065 63 chemical sand particulate matters from outdoor sources during prenatal, and postnatal which may lead to alterations in specific neural networks herting m. m. et al. [7]. showed that the air pollution causes oxidative stress, neuro inflammation, neurodegenerative pathology and cerebral vascular damage block, m. l. et al. [8]. worked impact assessment of the brick kilns emissions on human health and the environment in pakistan where the results showed that co, co2 and so2 are the most harmful due to the environment. none the less, so2, carcinogenic dioxin and pm have affection on the human health adversely khan, m. w. et al. [9], in iraq, there are many researchers studied the environmental impact evaluation of brick factories in baghdad which approved that the sulfur compound emissions that resulted from black oil burning caused soil and air contamination al-nuzal s.m.d. et al. [10] , in babylon which conducted heavy metals concentrations in air and soil that result from brick factories emissions issa. m. j. et al. [11] and in al-diwaneyah which studied particulate matters and heavy metals and their effect on the nearby residential communities al-khateeb .a. h.n et al. [4] in this study focuses on the environmental impact evaluation of brick industries in al-diwaneyah city by studying the brick factories site characteristics and measuring the ambient air quality in west of the city. 1.1. methodology 1determining the spatial map of the brick factories site, neighboring cities, neighboring residential communities and roads by using arch gis program. 2comparison between the brick factories site characteristics and the locational determinants in the iraqi environmental legislations. 3study the ambient air quality in the west city by measuring the pollutants concentrations in the ambient air that result from brick kilns discharges. 2. environmental legislations 2.1. instructions no. (3) for 2011.[3] one of the most relevant laws and constructions which deals with the site characteristics of factories is iraqi environmental determinants instructions of the projects establishment and monitoring the safety of their implementation no. 3 for the year 2011 which consists of 81 legal articles where the article no. 10 that has been stated the locations of brick factories establishment must be distant from 1the city's municipalities borders and the residential communities (more than 20 houses) with a distance more than five kilometers. 2the roads with distance more than one kilometer. 2.2. regulation no. (4) for 2012.[12] regulation of ambient air protection from pollution no. (4) for 2012. which consists of 22 legal articles where the article no. 8 which has been required that the chimney design and its height determining must be taking in the account the chemical and physical properties of emissions, the discharge size and its temperature, velocity and direction of winds, heights of the surrounding buildings and location topography. on the other hand, the article no.18 has stated that used fuel must be the natural gas or the liquid petroleum gas in addition to the natural gas as clean fuel due to the environment and also the sulfur content must be less than 2.5 % weight in the heavy black oil and maintained in work to use in any type of fuel that will protect the environment. 2.3. instructions no. (3) for 2012.[13] national determinants instructions of emissions of activities and operations no. 3 for 2012 which consist of 18 legal articles for regulation, determination and control the emissions of air pollutants and which deals with mobile and fixed sources. where it stated that the gases concentrations of fixed sources which have been used hydro carbonic fuel must be as shown in the table 1 below. table 1. standards of fixed sourced emissions air pollutants symbols source limits (mg/m3) smokes and visible pollutants all sources 250 nitrogen oxides (measured as no2) nox kilns gas fuel 350 liquid fuel 500 sulfur dioxide so2 all sources 500 total suspended particles tsp all sources 250 carbon monoxide co all sources old 500 new 250 3. productivity process there are two product processes of clay brick manufacturing, the manually which is not used nowadays and the mechanically process. the difference between these methods is in the preparation processes of the bricks which includes the mixing, grinding, and forming processes. the first process of bricks manufacturing is the excavating soil for preparation the raw material then transferring it into mixing, grinding, pressuring and forming machines and then the wet clay bricks will be produced which required spreading them in an open area for drying by sun temperature therefore the mentioned processes apparently are stopped or deaccelerated in the winter. after complete drying stage, the firing process is the final stage in which the dried bricks are transferred into the firing kiln where its size is (100 length * 20 width * 3 depth) as average. each factory produces as average (64000 bricks per day) and the heavy black oil quantities which have been consumed about (120 –135 liters per 1000 bricks) [environmental authority, 14]. the table 2 explains the manufacturing process details with potential environmental damages from each stage. table 2. the productivity process stages of brick manufacturing with associated environmental damages (researcher) manufacturing stages of bricks environmental damages excavation of earth soil depletion and ground water exposure to evaporation mixing & grinding of soil electricity consumption pressing into desired form drying by sun ------ firing in kiln discharge air pollutants bricks solid wastes 4. site characteristic al-diwaneyah city is the center of al-qadisiyah province where it is located about (180 km south of baghdad), the location of brick factories is 5 kilometers west of the official borders of al-diwaneyah municipality and are surrounded with two others towns, al-shafiyaa and saniyah, from south and north respectively. after 2003 and due to the change of the political system in iraq, which leads to the economic improvement of iraqi individuals, the need into construction has increased year by year and as result as the number of brick factories enlarged to cover this need, 64 ozeair abessi , mukhtar dh. abbas /al-qadisiyah journalfor engineering sciences 14 (2021) 062–065 where the number of factories became more than (15 factories) in this site and the total areas reached into (5.5 km2,) also the habituated areas have been unofficially expanded in the direction of factories location and the actual distance between the cities and brick sites become 3 kilometers. furthermore, if the expansion status continuous there many environmental crises faced in future, difficulty the living in the new residential regions because the ambient air quality which will be affected by air pollutant that produced from nearby brick factories, also difficulty of factories development because the proximity of residential communities. more of urbanization expansions were unplanned and uncontrolled because authority's weakness. the image 1 the spatial spreading of villages and towns due to brick factories site and the wind direction. figure 1. site plan of the brick industrial region with surrounded towns and villages 5. results and discussion the mobile plant for air quality monitoring which is manufactured by horiba company where it contains modern analyzers for sampling and measuring air quality instantaneously. it measures 12 types of gases in addition to the condition parameters such as wind direction, temperature, air pressure, wind speed and humidity. this study has been focused on four gases (so2, no2, co, and non-methane hydrocarbons nmhc) and for 12 days each day continues for 24 hours. the below table shows the maximum and minimum values of gases. table 3. the values of gases emissions in study region [environment authority, 14] days so2 (mg/l) no2(mg/l) co (mg/l) nmhc (mg/l) max. min. max. min. max. min. max. min. 1 0.011 0.002 0.018 0.006 2 0.9 0.4 0 2 0.012 0.001 0.026 0.004 2 1.9 0.7 0 3 0.004 0.001 0.017 0.002 2 1.9 0.3 0.1 4 0.007 0.001 0.017 0.004 2 2 0.3 0 5 0.009 0.001 0.024 0.002 3 2 0.9 0.1 6 0.014 0.002 0.037 0.003 2 1.8 0.9 0.1 7 0.02 0.003 0.049 0.006 2 1.9 1.1 0.1 8 0.043 0.006 0.054 0.009 2 1.9 0.7 0.1 9 0.018 0.005 0.019 0.005 2 1.9 0.5 0.2 10 0.025 0.002 0.024 0.006 2 1.9 0.2 0.1 11 0.006 0.002 0.016 0.004 2 1.9 1.1 0.1 12 0.012 0.005 0.031 0.002 2 1.9 0.3 0.1 avg. 0.015 0.003 0.028 0.004 2.083 1.825 0.617 0.083 fig. 2 shows the iraq standard of ambient air, the maximum and minimum values of no2 and so2which measured by apna 370-ce and aspa 370-ce analyzers respectively where the maximum value of no2 in most days is high than standard while the value of so2 is low. figure .2 concentrations of no2 and so2 in study region fig. 3 shows the maximum and minimum values of co which measured by apma 370-ce analyzer where the results seemed very stable and similar and in the same time lower than the iraqi standard where this is positive indicator due to air quality. figure .3 concentrations of co in study region the measure of non-methane hydrocarbons in air quality by apha 370-ceanalyzer which is very significant indicator due to the pollutant sources and have been used petroleum derivatives such as heavy black oil as fuel for kiln operation. fig. 4 displays the results of nmhc which have been showed their gap between the maximum and minimum values and also the maximum values very high than the iraqi standard. 0 2 4 6 8 10 1 2 3 4 5 6 7 8 9 10 11 12 c o n ce n tr a ti o n ( p p m ) time (day) co max. co mini. co iraq stand. 0 0.01 0.02 0.03 0.04 0.05 0.06 1 2 3 4 5 6 7 8 9 10 11 12 c o n ce n tr a ti o n s (p p m ) time (day) no2 max. no2 mini. so2 max. so2 mini. no2 iraq stand. so2 iraq stand. ozeair abessi , mukhtar dh. abbas /al-qadisiyah journalfor engineering sciences 14 (2021) 062–065 65 figure. 4 concentrations of nmhc in study region generally, there air pollution in the city's west that produced from the brick factories which located in the west and with prevailing wind direction therefore it is more harmful due to environment and human health. 6. conclusions *the location of brick factories in the present is not suitable because it is surrounded from three directions and in the future will create environmental troubles due to the town's expansion. *this site of brick factories has been caused pollution of ambient air quality in the west al-diwaneyah city. *appropriate and modern air pollution control devices must be installed for mitigation the emissions. *it is recommended to follow especial strategies and continue environmental monitoring for this site. references [1] manisalidis, i., stavropoulou, e., stavropoulos, a., & bezirtzoglou, e. (2020). environmental and health impacts of air pollution: a review. frontiers in public health, 8. [2] drago, g., ruggieri, s., bianchi, f., sampino, s., & cibella, f. (2020). birth cohorts in highly contaminated sites: a tool for monitoring the relationships between environmental pollutants and children's health. frontiers in public health,8. [3] al-waqi’a iraqi newspaper, no. 4225 (2012)," environmental determinants instructions of the projects establishment and monitoring the safety of their implementation no. (3) for the year 2011". [4] al-khateeb .a. h.n., and mahmoud b. m.(2020) " study of the ecological impacts of air pollutants emitted from brick manufacturing in al-sinaiya, qadisiyah governorate, iraq "plant archives vol. 20, supplement 2, 2020 pp. 176-181,e-issn:2581-6063. [5] misra.p., imasu. r., hayashida s., arbain a. a., avtar. r. and takeuchi.w. (2020) "mapping brick kilns to support environmental impact studies around delhi using sentinel-2 " isprs int. j. geo-inf. 2020, 9, 544, doi:10.3390/ijgi9090544. [6] perrinoc, gilardoni s, landi t, abita a, ferrara i, oliverios, busettom, calzolarif, catrambonem, cristofanellip, torre s d, esposito g, giusto m, moscas,paretis, ranticae, sargolinit, tranchidagandbonasonip.(2020) "air quality characterization at three industrial areas in southern italy " frontiers in environmental science, volume 7, article 196, doi: 10.3389/fenvs.2019.00196. [7] herting m m., younan d, campbell c e. , and chen jiu-ch.(2019) "outdoor air pollution and brain structure and function from across childhood to young adulthood: a methodological review of brain mri studies" frontiers in public health. volume 7, article 332, doi: 10.3389/fpubh.2019.00332. [8] block m l. and garcidueñas l c.(2009) "air pollution: mechanisms of neuroinflammation & cns disease" nih-pa author manuscript., 32(9): 506–516. doi:10.1016/j.tins.2009.05.009. [9] khan m. w., ali y, felice f. d., salmand a., petrillo a. (2019)" impact of brick kilns industry on environment and human health in pakistan " science of the total environment 678 (2019) 383–389. https://doi.org/10.1016/j.scitotenv.2019.04.369 [10] al-nuzal s.m.d., al-bakri s. a. and zankana. s. d.a. (2019)"environmental impact assessment for modern brick factory in baghdad, iraq"engineering and technology journal, vol. 37, part c, no. 3, 2019. doi: http://dx.doi.org/10.30684/etj.37.3c.12. [11] issa. m. j., hussainh. m., and shakeri.h(2019)." assessment of the toxic elements resulting from the manufacture of bricks on air and soil at abu smeache area southwest babylon governorate iraq " iraqi journal of science,2019, vol. 60, no.11, pp: 2443-2456, doi: 10.24996/ijs.2019.60.11.15. [12] al-waqi’a iraqi newspaper, no.4263 (2013),"regulation of ambient air protection from pollution no. (4) for 2012". [13] al-waqi’a iraqi newspaper no. 4242 (2012), "emissions national determinants of activities and operations no. 3 for 2012 " [14] environmental authority of al-qadissiyah , ministry of environment, republic of iraq. 0 0.2 0.4 0.6 0.8 1 1.2 1 2 3 4 5 6 7 8 9 10 11 12 c o n ce n tr a ti o n ( p p m ) time (day) nmhc max. nmhc mini. nmhc iraq stand. https://doi.org/10.1016/j.scitotenv.2019.04.369 http://dx.doi.org/10.30684/etj.37.3c.12 article al-qadisiyah journal for engineering sciences 15 (2022) 009–017 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: eng.mec.mas.20.3@qu.edu.iq (hind a. nafeh) https://doi.org/10.30772/qjes.v15i1.807 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. genetically compatible graphs for planetary gear train synthesis hind a. nafeh* and essam lauibi esmail department of mechanical engineering, university of al-qadisiyah, al-diwaniyah, iraq a r t i c l e i n f o article history: received 13 april 2022 received in revised form 20 may 2022 accepted 28 june 2022 keywords: degree of freedom genetically compatible graphs isomorphism planetary gear trains spanning trees synthesis vertex matrix a b s t r a c t planetary gear trains (pgts) are used in a wide range of mechanical applications. graphs are used to represent pgts. pgts are classified into single-planet and multi-planet gear trains depending on the number of vertices in the second level of the graph. in this paper, a novel method for synthesizing pgts up to the second level is developed. the first step in the synthesis process is the enumeration of spanning trees. a combinatorial analysis is then used to obtain the link assortment arrays and categorize them into families. based on the parent graphs and spanning trees, the geared graphs are generated for each family. for simplicity, the steps of the newly developed genetically compatible graphing method are applied to 5 -link, 1-dof planetary gear trains. the synthesis steps are programmed in matlab. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction for many years, many studies have focused on planetary gear train synthesis and analysis [1-14]. graph theory has aided pgt structural synthesis, resulting in the development of three distinct synthesis methods. the first method produces pgts with 𝑁 links from 𝑁-vertex parent graphs by assigning geared edges to the parent graph. this is known as the nonrecursive method [1-3]. according to some researchers, this method is complicated to implement on a computer and requires a large number of parent graphs. the second method, known as the recursive method, generates pgts with n links by adding graph components to pgts with (𝑁 − 1) links. [4-6]. however, the pgts enumerated by the recursive method are incomplete. the last method employs the parent-bar-linkage to enumerate pgts. however, it is not currently in use. [7, 8]. pgts with up to nine links have been studied using the methods described above [1-8]. for the reasons stated above, a method that easily provides a complete solution to the enumerated pgts is required. isomorphic graphs must be deleted as part of the solution. the presence of pseudo-isomorphic graphs, on the other hand, further complicates the isomorphism challenging task [5]. the synthesis results of pgts with more than six links are in disagreement [3, 6]. to avoid the problem of pseudo isomorphic graphs, chatterjee and tsai [9, 10] proposed the rooted graph of pgts. based on spanning trees of rooted graphs, a method for enumerating pgts is also proposed. hsu and lam [11, 12] proposed a graph model that is identical to all pseudo isomorphic graphs. in addition, hsu [13] proposed a method for detecting structural isomorphism. despite the fact that hsu [14] proposed a parent graph method for synthesizing pgts, he believed that synthesizing pgts with more than six links was not possible using an atlas of parent graphs. then, hsu [15] developed a new method based on acyclic graphs. shanmukhasundaram et al. [16] also synthesized pgts using acyclic graphs. yang et al. [17, 18] contradicted [15 and 16] and used parent graphs to generate pgts with up to nine links. shanmukhasundaram and colleagues [19] examined the recursive, non-recursive, and acyclic graph http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i1.807 https://doi.org/10.30772/qjes.v15i1.807 http://creativecommons.org/licenses/by/4.0/ 10 hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–17 based approaches in depth. graph theory enabled the modeling of pgt kinematic structure as well as the advancement of structure synthesis methodologies [20-28]. in this paper, geared graphs for a given number of links and dof are enumerated using a method that makes use of the correspondence between spanning-tree graphs and parent graphs. because the transfer vertices in a spanning tree graph are visible, all feasible gear pair connections can be identified, and geared graphs can be generated. it is justified that generating geared graphs from the entire collection of spanning-tree graphs and parent graphs results in the enumeration of an exhaustive and combinatorial complete set of geared graphs. the purposes of the work are listed as follows: to identify structural characteristics of pgts and translate them into graph representation language. to overcome the problem of pseudo-isomorphism. to promote an effective method to build a structural synthesis for planetary gear trains with any number of links and degree of freedom. to greatly prohibit the generation of isomorphic graphs. for the sake of simplicity and clarity, the new method will be applied to pgts with five links and 1-dof. it applies to greater degrees of freedom and links. in section 2, the concepts of graph theory are defined. in section 3, the synthesis of planetary gear trains is discussed. finally, in section 4, the conclusion about the synthesis is briefed and explained. 2. conceptions graph: a graph (g) contains a set of vertices (v), which represent the number of links, jointly with a set of edges (e) which represent the joint between links. 2.1. rooted graph a rooted graph consists of many vertices. it has one vertex that is different from other vertices. this vertex is named the root. it is usually utilized to represent the basis of a mechanism or fixed link. fig. 1 shows a functional representation of the well-known simpson gear train. figure 1. functional representation of the simpson gear train. to represent the well-known simpson gear train, first, consider the ground vertex as vertex 0. then the links are represented as vertices and distributed based on functional representation. after that, the dotted line is drawn for the revolute joint and a bold line for the gear joint. fig. 2 denotes rooted graph representation of the simpson gear train [22,23]. figure 2. rooted graph representation of the simpson gear train. 2.2. spanning tree a tree is a linked graph that doesn’t have loops. fig. 3 denotes the spanningtree graph of the rooted graph that is shown in fig. 2. figure 3. the spanning-tree graph of the rooted graph shown in figure 2. 2.3. parents graph if all the edges of a rooted graph of pgt are assumed to be revolute or have the same color, then the resulting graph is the parent graph. in the parent graph, there is no distinction between revolute and geared edges. fig.4 shows the parent graph of the rooted graph which is shown in fig. 2. by using the corresponding matrix equation, the parent graphs are synthesized. nomenclature: a the adjacency matrix n number of links 𝑎𝑖𝑗 the (𝑖, 𝑗) elements of the adjacent matrix o root or the ground vertex dof degree of freedom pgt planetary gear train e edges or the joint between links. v vertices f number of degrees of freedom 𝑉2, 𝑉3, … , 𝑉𝑚 number of binaries, ternary…m-nary vertices g graph [𝑉1, 𝑉2, 𝑉3, … , 𝑉𝑚] link assortment array l number of independent loops 𝑣 number of vertices 𝑚 the maximal degree of vertex hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–017 11 figure 4. parent graph of the rooted graph which is shown in figure 2. 2.4. adjacency matrix the following is a definition of an adjacency matrix element: 𝑎𝑖𝑗 = { 1 𝑖𝑓 𝑣𝑒𝑟𝑡𝑒𝑥 𝑖 𝑖𝑠 𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡 𝑡𝑜 𝑣𝑒𝑟𝑡𝑒𝑥 𝑗 0 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 (𝑖𝑛𝑐𝑙𝑑𝑒 𝑖 = 𝑗) where aij indicates the (i, j) elements of the adjacent matrix. it is a (v ∗ v) symmetric matrix and its diagonal elements are zeros. the degree of vertex is the summation of the elements of a row or column. the adjacent matrix has unique determination [23]. the adjacency matrix for parent graph shown in fig. 4 is: 𝐴 = [ 0 1 1 1 0 0 1 1 1 0 0 0 0 0 1 1 0 0 0 1 0 1 1 0 0 0 0 1 0 0 0 0 1 1 0 0 0 0 1 1 1 1 1 0 1 0 0 0 0] 2.5. fundamental circuit the addition of a chord to spanning tree results in the formation of exactly one circuit. a set of independent loops or fundamental circuits (fcs) are formed according to a combination of all circuits concerning a spanning tree. they serve as a foundation for the circuit space [27]. fc1: 0-1-5-2-0 fc2: 0-1-5-3-0 fc3: 0-2-6-4-0 fc4: 0-2-6-3-0 figure 5. the four fundamental circuits of the rooted graph shown in figure 2. 3. synthesis and analysis of planetary gear train the process of enumeration of pgts is split into three steps. first step, trees that are suitable for the creation of rooted graphs are enumerated. second step, parent graphs are enumerated. in third step, geared graphs are detected from parent graphs and spanning trees. the rooted graph of an n-link, fdof pgt comprises (𝑁 + 1) vertices and (2 𝑁 − 𝐹 − 1) edges; hence, the number of independent loops can be obtained from 𝐿 = 𝑒 − 𝑣 + 1 [2528]. the link assortment arrays of a spanning tree and a parent graph are expressed as [𝑉1, 𝑉2, 𝑉3, … , 𝑉𝑚] and [𝑉2, 𝑉3, … , 𝑉𝑚] , respectively. 𝑉2, 𝑉3, … , 𝑉𝑚 is the number of binary, ternary…m-nary vertices in the spanning tree or the parent graph, respectively. the maximal degree of a vertex 𝑚 is obtained from 𝑚 = 𝐿 + 1. 3.1. topological features of spanning trees it was shown, in a spanning tree, all geared edges are removed from the geared graph results. the spanning tree explains an open-loop kinematic chain that is consists of links which joined together via revolute joints. generally, the parent graph doesn’t have a unique spanning tree. fig. 6 shows two spanning trees corresponding to the graph shown in fig. 4. however, rooted-graph representation of pgts rules some particular arrangement of the vertices. for this reason, a reliable enumeration method is required to synthesize the pgts. so, a novel method to precisely enumerate spanning trees of n-link pgts is presented in this paper. figure 6. two spanning trees corresponding to the graph shown in figure 4. let v denotes the vertices, and e represents the number of edges in a graph. also, let vk refer to the number of vertices of degree k. so, v1 denotes the number of vertices of degree one, v2 the number of vertices of degree two, etc. as shown in eq. (1). 𝑉1 + 𝑉2 + 𝑉3 + ⋯ + 𝑉𝑚 = 𝑣 (1) where m refer to the maximal degree of a vertex. since a tree of v vertices contain v – 1 edges and every edge have two end vertices and each of the vk vertices are incident by k edges, as shown in eq. (2). 𝑉1 + 2𝑉2 + 3𝑉3 + + ⋯ + 𝑚𝑉𝑚 = 2(𝑣 – 1) (2) 12 hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–17 for example, for a 5-link, single-dof pgt, we have v = 6, e = 8, and m = 4, it follows that: 𝑉1 + 𝑉2 + 𝑉3 + 𝑉4 = 6 (3) 𝑉1 + 2𝑉2 + 3𝑉3 + 4𝑉4 = 10 (4) the flowchart for the enumeration of spanning tree graphs is shown in fig. 7. figure 7. flowchart for the enumeration of spanning tree graphs. by using a matlab program to solve eqs. (3) and (4), we obtain the following link assortment arrays for the spanning trees: [4 2 1 1 1 1], [3 2 2 1 1 1], [3 3 1 1 1 1], and [2 2 2 2 1 1]. see appendix b. the link assortment arrays are classified into families according to maximum vertex degree; the vertex with the greatest degree is chosen as the root. family 1: (maximum vertex degree = 4): [4 2 1 1 1 1] family 2: (maximum vertex degree = 3): [3 2 2 1 1 1], [3 3 1 1 1 1] family 3: (maximum vertex degree = 2): [2 2 2 2 1 1] table 1. spanning trees for the 5-link, single-dof pgt. family 1 family 3 [4 2 1 1 1 1] [2 2 2 2 1 1] family 2 [3 2 2 1 1 1] [3 3 1 1 1 1] 3.2. topological features of parent graphs based on equation (5) and (6), all conceivable link assortments for a given v-vertex graph can be derived. 𝑉2 + 𝑉3+ . . . + 𝑉𝑚 = 𝑣 (5) 2𝑉2 + 3𝑉3 + . . . +𝑚𝑉𝑚 = 2 𝑒 (6) taking (n = 5) for instance, we have (v = 6), (e = 8) and (m = 4). the link assortment eq. is shown in eq. (7). 𝑉2 + 𝑉3 + 𝑉4 = 6 (7) 2𝑉2 + 3𝑉3 + 4𝑉4 = 16 (8) hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–017 13 the flowchart for the enumerate of parent graphs is shown in fig. 8. five-link assortment arrays are achieved by using a matlab program: [4 2 2 2 2 4], [3 3 3 2 3 2], and [3 3 2 2 3 3]. the link assortment arrays are also classified into families according to maximum vertex degree: family 1: (maximum vertex degree = 4): [4 2 2 2 2 4] family 2: (maximum vertex degree = 3): [3 3 3 2 3 2], and [3 3 2 2 3 3]. the second family contains two vertices in the second level, whereas the first family contains only one vertex. figure 8. flowchart for the enumeration of parent graphs. table 2. parent graphs for 5-link, single-dof pgts. family 1 family 2 [4 2 2 2 2 4] [3 3 3 2 3 2] [3 3 2 2 3 3] 3.3. geared graphs now by comparing the parent graph and spanning trees for each family (1 and 2), we get the following geared graphs: table 3. geared graphs for 5-link, single-dof pgt. family 1 [4 2 2 2 2 4] [4 2 1 1 1 1] family 2 [3 3 3 2 3 2] [3 3 2 2 3 3] [3 2 2 1 1 1] [3 3 1 1 1 1] (a) (b) [3 3 3 2 3 2] [3 3 3 2 3 2] [3 2 2 1 1 1] [3 3 1 1 1 1] (c) (d) 14 hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–17 the new method can be implemented on a computer using an adjacency matrix and a nested-do loops algorithm. 3.4. isomorphism two graphs are isomorphic if their vertices and edges have a one-to-one correspondence, and their incidences are preserved. a link assortment array identifies each family. isomorphism cannot exist between graphs from different families. in table 3, for example, two of the four graphs in family 2 have the same spanning tree. the link assortment arrays of the parent graph and spanning tree of figures (a) and (c) are the same. the weighted vertex degree 𝑑𝑤 is calculated by assigning edge weights of one for revolute edges and two for geared edges. for example, the weighted vertex degree of vertices 0 through 5 of graph (a) shown in table 3 are 3 4 4 3 5 3, respectively. the weighted link assortment array for the graph shown in fig. (a) is [3 4 4 3 5 3], whereas the weighted link assortment array for the graph shown in fig. (c) is [3 4 5 2 5 3]. as a result, they aren't isomorphic. it should be noted that only graphs having the same link assortment arrays can be isomorphic. as a result, only graphs with the same link assortment arrays must be checked for isomorphism, and there are often few of them. a new algorithm based on the trail and graph marking is developed. if the vertex-edge of two graphs are equivalent, the graphs are isomorphic. the vertices are to be identified by a three-digit number 𝑑𝑡𝑑𝑝𝑑𝑤, where 𝑑𝑡 and 𝑑𝑝 represent the degree of vertex at the spanning tree and the parent graphs, respectively. the new vertex identification method takes into account not only the number of edges incident to the vertex but also the type of edges. the graphs of two pgts are shown in fig. 9 (a) and (b) (fig. 14 of ref. [29]). (a) (b) identification of the vertices by the three-digit number 𝒅𝒕𝒅𝒑𝒅𝒘 (c) (d) a possible trail connecting all of the vertices of the first graph (a), [( 666, 123, 135,234, 135, 135, 135, 333, 135, 123, 666, 258)] is chosen. vertices are numbered in the same manner. 𝑮𝑺𝟏 = [𝟒, 𝟓, 𝟔, 𝟕, 𝟏𝟏, 𝟑, 𝟐, 𝟏𝟏, 𝟗, 𝟏𝟎, 𝟏𝟏, 𝟑] 𝐺𝑆2 = [𝟒, 𝟓, 𝟔, 𝟕, 𝟏𝟏, 𝟑, 𝟐, 𝟏𝟏, 𝟗, 𝟏𝟎, 𝟏𝟏, 𝟑] geared strings figure 9. the steps for identifying isomorphism using the trail and graph marking method first, the vertices of the two graphs are identified by the three-digit number 𝒅𝒕𝒅𝒑𝒅𝒘. second, a possible trail connecting all of the vertices of the first graph (a) is chosen. vertices are numbered in the same manner as [(666, 123, 135, 234, 135, 135, 135, 333, 135, 123, 666, 258)]. repetition of vertex and edge is allowed. third, the two graphs are numbered according to the suggested trail. finally, check the numbering of the geared strings (𝑮𝑺𝒔) of both geared graphs. if they are not equivalent, then the two graphs are not isomorphic. because 𝑮𝑺𝟏 = 𝑮𝑺𝟐 , the two graphs are isomorphic. 3.5. functional representation the geared graphs shown in table 3 can be transformed to their corresponding functional diagrams as shown in appendix a. to start, each edge-labeling possibility of a spanning tree must be determined. fig. 10 shows all possibilities for labeling the edges of spanning trees. figure a.1 shows the graphs of 5-link 1-dof pgts that have only single-planet pgts. column 1: graphs showing one of the possible distributions of internal and external gear pairs. column 2: corresponding functional representation to column 1. figure a-2 shows a graph of a double-planet 5-link pgt. figure 10. possibilities for labeling the edges of spanning trees. fig. 11 shows the labelled graph representation and the functional representation of the first graph in table 3 which belongs to family 1. an internal gear pair will be represented by an upper-case g and an external gear pair will be represented by a lower-case g. 4. results this paper describes a method for synthesizing 5-link, 1-dof pgts. given a set of links, all possible link assortments are found, and the graphs associated with each link assortment are synthesized. table 1 shows the spanning trees for the 5-link, single-dof pgt. hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–017 15 figure 11. five-link pgts that have only single-planet fges to reduce the number of graphs generated and concentrate on methodology, the spanning trees were built with a vertex distribution up to the second level and a ground vertex degree greater than two. table 2 shows the parent graphs for the 5-link, single-dof pgt. table 3 displays the 5link geared graphs for the link assortments [4 2 2 2 2 4], [3 3 3 2 3 2], and [3 3 2 2 3 3]. the spanning trees and parent graphs are used to generate geared graphs. each geared graph represents a 5-link, single-dof pgt with a distinct topology and function. figure 10, for example, shows fivelink pgts that have only single-planet pgts. the detailed results for the synthesis of graphs are shown in appendix a. the results are a test of the current method's utility as a new method added to the previously existing technique. to automate the method, a computer program is created using a nested-do loops algorithm. 5. conclusion this paper presents a genetically compatible graph method to synthesize planetary gear trains. the new method is established on the link assortment arrays of spanning trees and parent graphs. geared edges are determined by the fact that a parent graph contains several spanning trees. the presented method can be utilized for pgts with any number of dofs. because this method makes use of a small number of spanning-tree graphs and parent graphs, it is possible to efficiently enumerate pgts with any number of links. it is easy to program on a computer, can be used directly to perform pgt synthesis, and can generate an exhaustive and combinatorial complete set of geared graphs. the matlab algorithm is built to perform this method and the results show precise graphs without many similarities. references [1] f. buchsbaum, and f. freudenstein. 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"graph-based efficiency analysis of simpson gear train." in 2018 international conference on advanced science and engineering (icoase), pp. 479-484. ieee, 2018. [25] esmail, essam l., and anahed h. juber. "an application of graph theory for the detection of degenerate structures in planetary gear trains." in international design engineering technical conferences and computers and information in engineering conference, vol. 85444, p. v08at08a025. american society of mechanical engineers, 2021. [26] hussen, hamed ali, essam lauibi esmail, and maasi f. al-mayali. "structure synthesis of planetary gear trains using graph partitioning." in aip conference proceedings, vol. 2386, no. 1, p. 040030. aip publishing llc, 2022. [27] hussen, hamed a., and essam l. esmail. "application of incidence matrix to topological structure and kinematic analysis of multi-planet gear trains." results in engineering 12 (2021): 100305. [28] n. a. tamather, l. e., essam, and a.n. hind, a graph-based approach for detection degenerate structures in multi-planet gear trains, cogent engineering, 9:1, (20220. [29] w.j. yang, h.f. ding, the perimeter loop-based method for the automatic isomorphism detection in planetary gear trains, asme j. mech. des. 140 (12) (2018) 123302, doi: 10.1115/1.4041572 . appendix a figure a.1 shows the graphs of 5-link 1-dof pgts that have only single-planet pgts. column 1: graphs showing one of the possible distributions of internal and external gear pairs. column 2: corresponding functional representation to column 1. figure a2 shows a graph of a double-planet 5-link pgt. graph representation functional representation hind a. nafeh and essam lauibi esmail /al-qadisiyah journal for engineering sciences 15 (2022) 009–017 17 appendix b a matlab program using an adjacency matrix and a nested-do loops algorithm to solve a system of 2 linear equations in 3 unknowns: clear clc close all n=5; dof=1; v=n+1; e=2*v-dof-3; l=e-v+1; m=l+1; k=1; d=zeros(m-1,m-1); for v2=0:n for v3=0:n for v4=0:n if(v2+v3+v4==v) if (2*v2+3*v3+4*v4==2*e) d(k,:)=[v2 v3 v4]; k=k+1; end end end end end disp('vertex degree listing la =') disp(' v2 v3 v4 '),disp(d article al-qadisiyah journal for engineering sciences 15 (2022) 042–047 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: rusul.s.hadi@uotechnology.edu.iq (rusul salah hadi) https://doi.org/10.30772/qjes.v15i1.812 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. study the mechanical properties of epoxy resin reinforcement by ziziphus spina-christi powder rusul salah hadi department of materials engineering, university of technology, baghdad, iraq a r t i c l e i n f o article history: received 26 april 2022 received in revised form 25 may 2022 accepted 2 july 2022 keywords: epoxy ziziphus impact test flexural test a b s t r a c t ziziphus spina-christi bark and other natural debris may be found in abundance in the nearby area. the mechanical qualities of all of these waste natural resources are outstanding, and they may be utilized more professionally to create composite materials for a variety of applications. epoxy resin modified with organic natural particles such as ziziphus spina-christi bark powder has been used as reinforcements in polymer matrixes instead of non-degradable synthetic reinforcement such as glass, carbon, or aramid. the tensile, impact and flexural characteristics of the ziziphus spina-christi bark particles enhanced epoxy resin are examined in this publication. this paper studies the effects of weight fraction (3, 5, 7 & 9%) on the characterization of composite materials. the results show that the mechanical characterization of epoxy improved when added 7% from the particles of christi. where the hardness increased up to 77 (mpa). also, the impact strength reached 8.7 (kj/m2 ) with a 7 wt% filler added, and the tensile strength increased from 18 (mpa) to 45 (mpa). the flexural strength of pure epoxy is 160 (mpa), and it increases linearly with the addition of ziziphus spina-christi bark to 173 (mpa). © 2022 university of al-qadisiyah. all rights reserved. 1. introduction epoxy resins may be made to display outstanding chemical resistance, high thermal & electrical resistance, tremendous adhesion, little shrinkage, and useful mechanical features, such as great toughness and strength, in addition to superior mechanical properties. manufacturing, packaging, aerospace, and building all benefit from epoxy resins. as a result, they are used in a broad range of applications from bonding & adhesive applications to electrical laminates to garment finishes to fiber-reinforced plastics to flooring and pavements [1]. zizyphus lotus bark (z. lotus), sometimes called jujube, is an angiosperm member of the rhamnaceae family. this family contains around 135–170 zizyphus species [2]. z. soil conditions in china, africa, iran, europe, and south korea, particularly cyprus, greece, sicily, and spain, are ideal for growing the lotus [3–4]. tea, honey, jam, oil, juice, bread, and cake are just some of the ways this plant is used in nutrition, health, and beauty. traditional medicine in the middle east and north africa uses a few sections of z. lotus to treat a wide range of ailments, including urinary tract infections, diabetes, fungal infections, skin infections, insomnia, bronchitis, and low blood sugar [5–6]. in contrast, the jujube, a delicious red fruit, was consumed by indigenous peoples in huge numbers fresh, dried, and processed as a food source. [7]. table 1. mechanical properties of epoxy resin flexural strength (n/) 53 compressive strength (n/) 50 tensile strength (n/) 25 viscosity (poise ) 0.5-1.0 poise young's modulus (n/) 1.060 density( gm/) 1.1 http://qu.edu.iq/ mailto:rusul.s.hadi@uotechnology.edu.iq https://doi.org/10.30772/qjes.v15i1.812 http://creativecommons.org/licenses/by/4.0/ rusul salah hadi /al-qadisiyah journal for engineering sciences 15 (2022) 042–047 43 purpose of the study: to make samples of composites of epoxy resin reinforced with zizyphus lotus bark and study its effect on mechanical properties (hardness "shore d", tensile test, impact test, and flexural test). m. alsaadi & flexural qualities & colleagues [8].r. pragathees & s. senthil [9] investigated the flexural properties & tensile of an epoxy resin filled with 3percentage, 5percentage, 7percentage, & 9percentage vol percent groundnut shell powder. the findings indicated that the additive of zizyphus lotus bark improves mechanical characteristics. 2. experimntal setup 2.1. epoxy resin the hardener used was poly inject ep 10. it is liquid and added to the resin in a weight ratio of 1:3 (hardener: resin), and thus the chemical bonding and crosslinking were formed within the epoxy resin. produced by (al-rakaez building materials in amman) and made in (egypt arabic). typical properties of a resin used in the current experimental work are listed in table 1. 2.2. zizyphus lotus bark the root barks of zizyphus lotus were extracted with water, chloroform, ethyl acetate, and methanol to determine their anti-inflammatory and analgesic activities. aqueous extract (50, 100, and 200 mg/kg) given intraperitoneally (i.p.) showed a significant and dose-dependent antiinflammatory and analgesic activity. chemical analysis of ziziphus lotus bark after (x-ray fluorescence) using reagents compton secondary molybdenum and barkla scatters hopg. showing in table 2. the test was completed at the university of technology, baghdad, iraq . table 2. chemical analysis of ziziphus lotus bark 2.3. preparation of composites all specimens were composited using a rubber mold. a layer of wax was applied to the mold to allow for easy removal of the specimen. table 3. composition of specimen composites specimen composition 1 100% epoxy resin 2 epoxy + 3% (zp) 3 epoxy + 5% (zp) 4 epoxy + 7% (zp) 5 epoxy + 9% (zp) determining quantities of ziziphus spina-christi bark particles(zp) (3, 5, 7, and 9wt%), and epoxy resin were combined carefully in a container to make a uniform mixture. the mixture was swirled for ten minutes after adding the hardener. after 24 hours, samples were removed from the mold & heated in a furnace set to 55 degrees for (3) hours to eliminate every tension and to complete the bonding between the filler & resin [11& 12]. table 3. summarizes the composition of specimen composites. zizyphus lotus bark zizyphus lotus powder sieving pure epoxy epoxy+zp figure 1. preparation of composites 3. mechanical tests 3.1 tensile test this test is performed according to (astm d638) in room temperature. fig.1.shows specimens for tensile test stander matching with astm d638-03[13]., figure (3) shows the tensile strength machine used in this research, the test was completed in the material engineering department/ university of technology/ baghdad/iraq. figure 2. tensile test stander 3.2. flexural test the flexural test can also be called as bend test, samples have been cut into the dimensions (125*12.7*3.2) mm according to astm d 79086 [14]. z symbol element concentration abs. error 16 s sulfur < 0.00020% 0.0% 15 p phosphorus 0.00033% 0.0005% 14 si silicon < 0.00058 % 0.0% 13 al aluminum < 0.0013% 0.0% 12 mg magnesium < 0.0065% 0.0% 11 na sodium < 0.045 % 0.0% 44 rusul salah hadi /al-qadisiyah journal for engineering sciences 15 (2022) 042–047 figure 3. tensile test device figure 4. show flexural test stander. the flexural strength is calculated according to the equations. f. s = 3pl 2bd² (1) where f.s: flexural strength (mpa). p: force at fracture (n). l: length of the sample between predicate (mm). b:thickness (mm). d:width (mm). 3.3. impact test fig.5.demonstrates the standard dimension of samples according to (iso180) [15]. impact resistance is calculated for samples from the following relationship [16]. figure 5. show impact test stander gc = uc a (2) where gc: impact strength of the material (j/m 2). uc: impact energy (j). a: cross-sectional area of the specimen (m2). this test is performed according to (iso180) at room temperature. samples have been cut into the dimensions (80*10*5) mm. the inspection was done in the material engineering department/ university of technology/ baghdad/iraq. 3.4. hardness shore (d) the astm of hardness shore d test is conducted related on (d-2240) at room temperature(annual book of astm standard, 1988). samples cut off into a diameter of 40mm and a thickness of 5 mm. device founded in the polymer laboratory at the materials engineering department, university of technology. per each sample, five hardness tests were taken, and the average hardness was fixed. figure 6. hardness shore test stander 4. results and discussions 4.1 tensile test the tensile strength of samples epoxy/ ziziphus spina-christi bark powder in fig.7. shows increases with the addition of additional 5 percent and 7 percent weight fractions of ziziphus spina-christi bark powder, but begins to decline with the addition of a 9 percent weight fraction of ziziphus spina-christi bark powder, according to the findings. increased tensile strength values were observed at (5 percent and 7 percent weight fraction ziziphus spina-christi bark) concentrations, which is likely due to the fact that tensile properties can be influenced by a variety of factors, including filler content rather than the particle-matrix interface, homogeneous particle distribution within the resin, & the stiffness of the reinforcing particles; all of these factors contributed to the enhancement of tensile properties [17 & 18]. there may have been a lack of bonding between resin and filler, which caused microcracks to form at the interfaces of the sample composites when 9 percent weight fraction ziziphus spina-christi bark powder was used in epoxy resin [19]. fig.8. illustrates the connection between the modulus of elasticity & the weight fraction of ziziphus spina-christi bark powder in epoxy resin (2). it can be concluded that the elasticity modulus qualities of epoxy resin improve with increasing weight fractions of ziziphus spina-christi bark powder (5 and 7 percent), but that the elasticity modulus qualities of epoxy resin decrease with the addition of ziziphus spina-christi bark powder (9 percent) in epoxy resin. in part, the high strength of ziziphus spina-christi bark powder is responsible for this rise in modulus of elasticity. consequently, the modulus of elasticity enhanced from (2.3 gpa) for the epoxy to (11 gpa) for epoxy combined with 7 percent ziziphus spinachristi bark powder, a significant increase. when compared to the pure sample, the elastic modulus values increased by around 4percentage on average. in part, this is due to the average particle size & uniform distribution of ziziphus spina-christi bark powder within the epoxy resin, as well as the ease with which the polymer matrix material diffuses; as a thickness=4 mm rusul salah hadi /al-qadisiyah journal for engineering sciences 15 (2022) 042–047 45 figure 7. tensile strength of the specimen figure 8. modulus of elasticity of specimen result, excellent interfaces between the reinforcing & matrix materials are required [20]. it was discovered that the addition of 9 percent weight fraction ziziphus spina-christi bark powder to epoxy resin resulted in a drop in modulus of elasticity from 11.1 to 9.2 gpa. that's because reducing deformation by rising the surface contact area between the matrix & reinforcement [21] 4.2. flexural test epo/ziziphus spina-christi bark composites with various filler weight percentages are shown in fig.9. flexural strength of the pure epoxy was 160 mpa, which grew linearly with the addition of ziziphus spinachristi bark up to 169 percent, or 7 wt. percent, but decreased to 165 with the addition of 9 percent). unofficially, the inclusion of ziziphus spinachristi (7 percent weight) increases the adhesive properties of the composite with increasing mechanical joining among epoxy and filler, which rallies stress transfer after application of loads [18]. when 9 percent weight ziziphus spina-christi filler was added, flexural strength was reduced because the structure's integrity deteriorated due to the agglomeration and gaps. the losses in flexural strength were attributed in part to the existence of ziziphus spina-christi in the matrix, which is in line with [22]. device established at materials engineering department, university of technology. by using the machine type laryee, chinese made (model 1031). figure 9. flexural strength of the specimen the fig.10. the flexural modulus of epoxy / ziziphus spina-christi bark at various filler weight fractions 7. the pure epoxy has a flexural modulus of 2 gpa & is linearly increased by 7.8 gpa percent up to 7wt. percent ziziphus spina-christi bark, but is decreased to 6.2 gpa when 9 percent ziziphus spina-christi bark is added, as shown in figure (8). the stiffness of the epoxy in combination with its content may contribute to the composites' increased flexural modulus. the filler may restrict the polymer chain's free flow, hence limiting the polymer's capacity to deform. this might be attributed to the improved interfacial bonding between the filler & matrix, wherever stiffness is determined by the filler quantity, filler type, & filler dispersion similarity. these parameters, which determined the proper filler dispersion in the composite structure, may be checked by watching the composite's linear modulus increase [23]. by adding 9percentage weight to the ziziphus spina-christi bark, the flexural modulus qualities are limited. this is due to material aggregation & a lack of homogeneity between the filler & the cause polymer, which degrades the stiffness of the samples[24]. 4.3.hardness shore d figure 11. illustrates the hardness shore d values for the epoxy reinforced ziziphus spina-christi bark the findings may indicate an increase in hardness with the addition of ziziphus spina-christi bark, with 77 hardness shore d with 7 wt percent ziziphus spina-christi bark. increased ziziphus spina-christi bark content owing to an increase in hardness. this might be because hardness is often thought to be a surface attribute, or because ziziphus spina-christi bark includes materials that are harder than pure epoxy, resulting in a rise in hardness. the rationale for enhancing the hardness of composite materials is that the addition of filler results in a rise in resistance to plastic deformation; this outcome is consistent with [25]. 4.4. impact test the impact strength results for the epoxy/ziziphus spina-christi bark samples are shown in fig. 12. with a powder content of 14.5 kj/m2 and a filler content of 7 wt percent, this characteristic implies increased adhesion 0 10 20 30 40 50 1 2 3 4 5 t e n si le s tr e n g th ( m p a ) ziziphus spina-christi bark (wt.) 0 2 4 6 8 10 12 1 2 3 4 5 m o d u lu s o f e la st is it y (g p a ) ziziphus spina-christi bark (wt.) 150 160 170 180 1 2 3 4 5 f le x u ra l s tr e n g th ( m p a ) ziziphus spina-christi bark (wt.) 46 rusul salah hadi /al-qadisiyah journal for engineering sciences 15 (2022) 042–047 figure 10. the flexural modulus of the specimen figure 11. the hardness shore of the specimen figure 12. the impact strength of the specimen of the filler matrix (epoxy) and was caused by the reduction of void spaces in polymeric composites. this may be because filler particles absorb more stress energy as their concentration in the matrix resin rises [26]. additionally, this chart demonstrates that the impact strength is reduced with the addition of (9 percent by weight) ziziphus spina-christi bark, indicating that the matrix resin is likely insufficient to effectively transmit the stress generated by a sudden impact when combined with the filler's low absorption capacity. a high filler content has been demonstrated to improve the possibility of fiber aggregation, resulting in regions of high stress that need less energy to propagate [27,28]. 5. conclusions 1. the tensile strength of samples epoxy/ziziphus spina-christi bark powder rises with the addition of 5 percent and 7 percent weight fractions of ziziphus spina-christi bark powder, but begins to diminish when the weight fraction of ziziphus spina-christi bark powder is increased to 9 percent. 2. with the addition of 9 percent weight fraction ziziphus spina-christi bark powder to the epoxy resin, the tensile strength reduced from (45 mpa to 40 mpa. this discovery may be explained by a lack of bonding between the resin and the filler, which resulted in the formation of microcracks at the interfaces during the loading of the sample composites. 3. adding increasing weight fractions of ziziphus spina-christi bark powder into epoxy resin results in the development of 3-properties of the elasticity modulus, while adding a higher weight fraction of ziziphus spina-christi bark powder results in a reduction in 3-properties of the elasticity modulus. the nature of ziziphus spina-christi bark powder in terms of high strength is responsible for this increase in the property modulus of elasticity. when compared to the pure sample, the elasticity modulus values have increased by approximately (4 percent). this is because of the mean particle size of ziziphus spina-christi bark powder in the epoxy resin & the ease with which the polymer matrix material diffuses into the epoxy resin. this indicates that the interfaces between the reinforcing material & the matrix material have been properly formed. when ziziphus spina-christi bark powder was added to epoxy resin, the modulus of elasticity reduced from (11 gpa to 9.2 gpa (9 percent weight fraction). this reduction is because of the reduction in deformation caused by the increased surface contact area between the matrix and reinforcement. 4. the flexural strength of pure epoxy is 160 mpa, & it increases linearly with the addition of ziziphus spina-christi bark ziziphus spina-christi bark until 173 percent, which is equivalent to 7wt. percent, but it decreases to 171 mpa with the addition of 9 percent ziziphus spina-christi bark in conjunction with the addition of 9 percent weight of ziziphus spina-christi filler, there is a decrease in structural integrity as a result of agglomeration & the existence of voids. this is the underlying reason for the lower flexural strength. 5. the flexural modulus of pure epoxy is 2 gpa, & it increases linearly with the addition of ziziphus spina-christi bark, increasing by 7.8 gpa percent up to 7wt. percent ziziphus spina-christi bark, but it decreases to 6.2 gpa with the addition of 9 percent ziziphus spina-christi bark, indicating a reduction in strength. the addition of ziziphus spina-christi bark at a concentration of 9 percent by weight results in a reduction in the flexural modulus characteristics. due to aggregation of the material & homogeneity filler with the causing polymer, the stiffness of the samples is reduced as a result of this. 6. it is possible to see an increase in hardness with the addition of ziziphus spina-christi bark content, with 7 weight percent ziziphus spina-christi bark showing 77 with 7 weight percent ziziphus spina-christi bark due to an increase in the hardness. the addition of fillers to composite materials results in a material that is more resistant to plastic deformation, which in turn increases the hardness rate of the composite material. 7. in the case of the epoxy/ziziphus spina-christi bark samples, the impact strength results showed an 8.7 kj/m2 with a 7 wt% filler adding; this behavior implies enhanced matrix (epoxy) filler adhesion, which may be attributed to the filler particles absorbing more stress energy as their presence in the matrix rises. 0 3 6 9 1 2 3 4 5 6 f le x u ra l m o d u lu s (g p a ) ziziphus spina-christi bark (wt.) 0 20 40 60 80 100 1 2 3 4 5 h a rd n e ss s h o re d ziziphus spina-christi bark (wt.) 0 4 8 12 16 1 2 3 4 5 im p a ct s tr e n g th ( k j/ m 2 ) ziziphus spina-christi bark (wt.) rusul salah hadi /al-qadisiyah journal for engineering sciences 15 (2022) 042–047 47 the impact strength drops with the addition of ziziphus spina-christi bark (9 percent weight) to 7.5 kj/m2 ziziphus spina-christi bark owing to the matrix resin's inability to efficiently transmit the stress generated by a quick impact combined with the filler's poor water absorption characteristic. in certain circumstances, it has been shown that a great filler content enhances the possibility of fiber aggregation, resulting in areas 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[28] p. a. s.; k. j.; g. u.; and s.t. composites science and technology, 67 ( 3-4) ( 2007),453–461. article al-qadisiyah journal for engineering sciences 14 (2021) 083–091 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: haithamalkalidy@yahoo.com (haitham al-thairy ) https://doi.org/10.30772/qjes.v14i2.750 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. structural behavior of lightweight reinforced concrete columns subjected to eccentric loads at high temperature faaiza al-naqeeb a and haitham al-thairy b* a msc student at civil eng. depart. / college of eng./ university of al-qadisiyah, iraq b civil eng. depart. / college of eng./ university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 5 may 2021 received in revised form 2 june 2021 accepted 13 june 2021 keywords: eccentricity, lightweight concrete, normal weight concrete, temperature , ultimate strength. a b s t r a c t this paper presents an experimental investigation on the behavior of six reinforced concrete columns under elevated temperature. a lightweight expanded clay aggregate (leca) was used in three reinforced concrete columns, in remaining three columns natural aggregate was used. all reinforced concrete (rc) columns have similar square cross-sectional dimensions of 150mm×150 mm, and 1250mm total length. the columns were designed according to aci committee 318-2014 and exposed to different elevated temperatures of 400 ºc and 500 ºc. after exposure to elevated temperature, the columns were axially loaded by compression force using an eccentricity ratio (e/h) equal to 0.5. the experimental results demonstrated a remarkable decrease in the ultimate carrying capacity of the columns when subjected to elevated temperature. the experimental test results have also revealed that the lightweight reinforced concrete columns have more fire resistance than the normal weight reinforced concrete columns under same elevated temperature. the ultimate load capacity of lightweight reinforced concrete (lwrc) columns decreases by about 6.5 % and 14.3 %, at elevated temperature of 400 ºc and 500 ºc respectively, compared with the control column at ambient temperature. however, the ultimate load capacity of normal weight reinforced concrete (nwrc) columns decreases by about 14.15 % and 28.6 %, at elevated temperature of 400 ºc and 500 ºc ,respectively, compared with the control column at ambient temperature. this reduction in the load resistance of the columns might be due to degradations in all properties of concrete and reinforcing steel bars when exposed to high temperatures. in addition, one of the possible reasons for the reduction in the load resistance may be due to decrease in bond strength between concrete and steel, when subjected to heat. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction a column is a vertical structural member with a height-to-least-lateraldimension ratio greater than three is usually used to carry compressive loads d. j. akers et al.[1] . the columns are considered as the most important members because they transfer loads to the supports and foundations and any failure in the column has a critical location may cause significant damage to the building a. alhassnawi, m. and alfatlawi [2]. hence, it is necessary to pay attention to strengthening the columns and making them fulfil their intended purpose. concrete is widely used as a primary structural material in building construction where fire resistance is one of the key considerations in the design. the elevated temperature induced from fire could cause a deterioration of material and mechanical properties of structural members. for lightweight concrete (lwc), http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 84 faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 expanded clay is a more convenient from others type of aggregate, because it does not deform at high temperatures, and during heating of concrete at high temperature, where this aggregates have lower expansion v. jocius and g. skripkiunas [3]. lightweight aggregate has superior heat stability, lower thermal expansion, and lower thermal conductivity coefficient than normal-weight concrete [4, 5]. in addition, lightweight aggregate concrete (lwac) has many benefits, including enhanced resilience, expanded fire-resistant capability, significantly minimizing dead load and element dimension f. zulkarnain and m. ramli [6]. furthermore, one of the structural importance of lwc is in fire resistance as its thermal expansion is low (about half) compared with nwc real et al. [7] in addition to the low density, and low thermal expansion coefficient [1]. most kinds of lwc inherently possess good fire resistance compared to nwc chandra et al. [8]. moreover, the residual strength of lwc was found to be higher than that of nwc after exposure to fire according to aci 213r [9]. therefore, one possibility of using lwc is to protect steel bars when exposed to high temperature. in addition, the lwc advantage in columns is typically based on a drop in project costs, high efficiency or a mixture of both materials i. l. concrete and a. wet [10]. the lwc had a better performance in the raised temperature condition compered with the normal aggregates concrete. this results was obtained from many researches [10,11,12,13]. there are no adequate studies on the use of lightweight concrete in the design of concrete columns exposed to elevated temperatures. haddad and ashour [14] conducted an experimental study to investigate fibrous lightweight aggregate concrete small columns' thermal efficiency. seventy-two column specimens with dimensions of 120×120 mm (width and height) and 400 mm length with different lateral confinements of steel were sampled and casted with and without fiber reinforcement of hooked steel. the prepared specimens were test at age of 28 days of curing and subjected to higher heating degree ranged from 300 ºc to 700 ºc. from the results it has been noted a remarkable decrease in rigidity and the compressive of the load capacity, in addition to an increment within their strain at peak stress when exposure temperatures up to 400 c. thermal cracking was related to exposure heat, with the use of steel fibers or steel confinement minimizing the frequency of the cracking. column specimen failure modes ranged from brittle to semi-ductile, with longitudinal steel buckling observed in those heated to 700 c. construction professionals are particularly concerned with the behavior of building structures in certain conditions, thus constructing buildings and structures that minimize the risks to people and property to the extent possible of the business and standing in the construction business[15],[16]. also, the columns which were subjected to eccentric loading collapsed as the concrete was compressed in the compression face of the column after clear displacements and cracks fomented in the stress face othman et al. [17]. a significant number of studies were conducted on the effect of fire on reinforced concrete columns and other studies focus mainly on the fire influences on the eccentrically loaded rc columns. for instance, an experimental study was conducted by jau and huang [18] on twenty-two reinforced concrete corner columns with 2700 mm length and crosssectional dimensions of (300×450mm) under high temperature .the parameters considered in the tests were the concrete cover thickness, concrete compressive strength, reinforcement ratio, eccentricity ratio, and fire duration. it was observed that the eccentricity proportion, the compressive strength of concrete, the steel reinforcement ratio, the cover thickness of concrete, and the fire period are the variables influencing the occurrence of cracks in the essential series. the presence and features of surface fractures, nevertheless, do not explicitly contribute to the reduction in strength. lie and woolerton [19] presented an experimental study to examine the effect of different parameters such as the shape of cross section, thickness of concrete cover, reinforcement, aggregate type, load, and load eccentricity on the fire resistance of rc columns. forty-one full-size rc columns were cast and tested under standard fire conditions. the test results have revealed that using carbonaceous aggregate increased the fire resistance of rc columns. also, heavy reinforcement columns were noticed to give higher fire resistance and the end conditions influenced the slenderness ratio of the column, which in turn decreased the fire resistance with increasing slenderness ratio. the effect of fire flame burn on the performance and load-carrying capability of reinforcement concrete columns was investigated by kadhum [20]. one hundred and twenty columns were classified to two series with target compressive strength of 30 and 40 mpa, and series labeled a and b, respectively. the first set samples were concentrically loaded, while the second and third set samples were loaded with eccentricities of 30 and 80 mm. column specimens have been designed to sustain a full capacity load cell (150 tons) with a lifetime of 2 months after being burnt at temperature ranges of 400, 600, and 750 °c with a fire flame over an exposure time of 1.5 hours. test results have shown that the rise in fire temperature has a major influence on the mid-height lateral deflection of column samples for series a and b series. this research presents and discusses an experimental study of the behavior of lwrc columns and nwrc columns exposed to elevated temperatures under eccentric loading. finally, this study will come up with useful and essential conclusions that may be used for more practical and safer design of eccentrically loaded rc columns exposed to elevated temperature. 2. experimental program 2.1. rc column specimens six rc columns were considered in this study and designed according to aci 318-14 [21]. based on the tests of compressive strength, the normal weight rc columns also cast using nwc and lwc with equivalent compressive strength equals to 27 mpa, and 17 mpa, respectively . 2.1.1. material characteristics 1. concrete mixture: karasta ordinary portland cement (type i) manufactured in iraq was used for concrete mixes throughout the work. this cement complied with the iraqi specification (iqs, no.5:1984) [22]. fine aggregates were used from well-graded natural sand with a fineness modulus of 2.49 and so3 equals to 0.23 % conforming to the iraqi specification (iqs, no.45:1984) [23], zone 2. also, the expanded clay aggregate (leca) with dry density of 434 kg/m3, maximum size of 10 mm, specific gravity of 0.293, fineness modulus 3.19, and absorption faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 85 of 35.68% , and fineness modulus of 3.07 was used as a full replacement of the coarse aggregate (see fig. 1). the sieve analysis test of leca shown in table 1 indicates that the lightweight aggregate used is complying with the requirements of the astm c-330 [24], and coarse aggregate with a maximum size of 14 mm was used according to iraqi specifications (iqs no. 45/1984) [23] to obtain nwc. the lwc mixture with mix proportions of 1:1.744:0.5 (cement: sand: aggregate) and with water cement ratio (w/c) of 0.3 was designed based on aci code (aci 211.2-1998) [25] and utilized to cast the rc columns. also, the nwc mixture with mix proportions of 1.0:1.6:2.6 (cement: sand: aggregate) and with water cement ratio (w/c) of 0.41 was designed based on aci code (aci 211.1-1991) [26] and utilized to cast the rc columns. three concrete cubes with dimensions of 150mm× 150mm×150 mm and three concrete cylinders with 200mm height ×100mm diameter for each mixture, have been cast, cured, and tested to determine the tensile and compressive strengths of the concrete at ambient temperature based on astm c 2012 specifications [27]. the findings demonstrated that the concrete's average tensile and compressive strengths are 1.49 mpa and 17 mpa, respectively for nwc, and 1.98 mpa and 27 mpa respectively for lwc. in addition, the dry density of lwc and nwc was 1840.6 kg/m3 and 2361.5 kg/m3, respectively. figure 1. light weight expanded clay aggregate (leca) used in current study. table 1: grading of light weight expanded clay aggregate. sieve size (mm) cumulative% by weight passing sieve size (mm) conformed to i.q.s 12.5 100 100 ok 9.5 87 80-100 ok 4.75 8 5-40 ok 2.36 1 0-20 ok 2. steel bars: four different sizes of deformed steel bars with diameters of 16mm, 12mm, 10mm, and 8 mm with the strength grade of g60 were utilized as longitudinal and transverse reinforcement. uniaxial tensile tests were carried out to determine the yield stress, ultimate strength, and modulus of steel bars' elasticity, as summarized in table 2. table 2. the uniaxial tensile tests result of the steel bars used in the present study diameter (mm) yield stress fy (mpa) modulus of elasticity (mpa) εy= fy /ec ultimate strength fu (mpa) 8 318 200000 0.00159 447 10 461 200000 0.002305 545 12 530 200000 0.00265 628 16 557 200000 0.002786 666.50 2.1.2 geometrical characteristics and reinforcement details. the geometrical and reinforcement details of the lwrc and nwrc columns specimens used in the present study are illustrated in table 3 and fig. 2 respectively. all columns were designed to resist the same axial compressive load which is 600 kn with eccentricity ratio (e/h) of 0.5 in order to compare the reduction in the strength of lwrc and nwrc columns after the exposed to the elevated temperature 400˚c, and 500˚c respectively except one column being tested without exposure to heating which is considered as the control specimen . each column has the same square cross section with dimension of 150×150 mm and 1250 mm length. the upper and lower parts ends of the columns were designed as corbels according to aci 318-14 [21] specifications with dimensions of 240mm width, 150mm depth, to support the bearing plate used to achieve the required eccentricity and to prevent the local crushing and bearing of the concrete due to concentration of the stress at the upper and lower ends of the column. dimensions of the column were chosen to fit the dimensions of the electrical furnace manufactured in this study along with the dimensions of universal testing machine. in addition, for lwrc columns a minimum steel area (as ≥ 1%) or 4ø16mm and 2 ø12 was used for the main longitudinal reinforcement, while for nwrc a minimum steel area (as ≥ 1%) or 4ø12 mm. 9 ties were used as a transvers reinforcement using ø 8mm@131 mm c/c for each lwrc and nwrc columns, whereas, 9 ties were used as a transvers reinforcement using ø 8mm@131 mm c/c. the corbels were designed with 2ø16 as main reinforcement and ø10mm at 80 c/c spacing as transverse reinforcement. all dimensions in mm figure 2. dimensions and reinforcement details of rc column specimens 86 faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 table 3. details and designation of rc column specimens. 3. thermal and structural tests 3.1. thermal tests thermal tests were conducted on the concrete cubes, concrete cylinders, two nwrc columns, and two lwrc columns, after 28 days of curing by using the electric furnace after being air-dried for 10 days. the column specimens were tested thermally in the electric furnace by exposing them to different elevated temperatures (400˚c, and 500˚c). the concrete cubes and cylinders were thermally heated using an approximately identical heating rate exposed to the corresponding rc columns. the electrical furnace was used to impose high temperatures to the rc column samples before the axial compressive load was applied. the dimensions of the electrical furnace are 1300mm length, 330mm depth and 290mm height with the highest applicable temperature of 900ºc. the details of the electrical furnace equipment are shown in fig. 3. figure 3. close-up details of the electric furnace. for each rc column specimen, a single type-k thermocouple with a maximum temperature capacity of 600℃ was connected at mid-height of main reinforcement steel bars to measure the steel temperatures inside the concrete. fig. 5.a shows thermocouple used for steel bar reinforced. also, an external thermocouple shown in fig. 4.b was also attached to the concrete surface with a maximum temperature capacity of 1200℃ to measure and moniotor the surface temperature of the concrete. the two type-k thermocouples were connected to a digital monitor to record the temperature of the concrete and the reinforcement steel bars during the thermal tests. the locations of the steel bars thermocouples are shown in fig. 4.c. athermocouple used for steel. bthermocouple used for concrete. cinstalling thermocouples to the steel bar figure 4. types and positions of thermocouples. 3.2. mechanical tests the rc column specimens were tested using a hydraulic universal test machine with a maximum capacity of 2000 kn and minimum loading rate of 3 kn/min. a mechanical method was used in the recording and monitoring the load increment to the column. the heated rc column specimens along with the control specimens were subjected to one axial static point load up to failure using the mechanical test machine. two bearing plates were utilized at the bottom and top ends of the column to distribute the axial load over the loaded area and to achieve the required eccentricity. the bearing steel plate of columns is very important when testing the rc columns under eccentric loads to prevent concrete crushing and stress concentration at the column ends. the bearing steel plate is 20 mm in thickness to prevent the failure or deformation of the plate with a dimension of 150×180 mm (width ×length). the required eccentricity was achieved by using the two bearing steel plates over the corbel at the locations length such that the resultant of the applied pressure on the plate is located at the intended value of the eccentricity from the center of the column section, as demonstrated in fig. 5.a. on the other hand, the boundary conditions of the column was arranged to represent the simply support condition by using a steel rods at top and bottom end with diameter of 10 mm which allow the ends to rotate freely about the perpendicular axis and prevent the end moving in vertical and horizontal directions. the load was applied in small increments and the measurements were recorded until failure occurs. cracks initiation and propagation were observed and marked on the surfaces of the rc columns specimens. in addition, two dial gauges of 0.01 mm accuracy were used to measure the horizontal and axial displacement: one of dial gauges was installed at the mid-height of the column to measure the horizontal displacement while other one was main reinforcement symbol stirrups target temperature ˚c (concrete) 4ø16 and 2ø12 0.5n20 ø8 @131mm c/c 20 4ø16 and 2ø12 0.5n400 ø8 @131mm c/c 400 4ø16 and 2ø12 0.5n500 ø8 @131mm c/c 500 4ø12 0.5n20 ø8 @131mm c/c 20 4ø12 0.5n400 ø8 @131mm c/c 400 4ø12 0.5n500 ø8 @131mm c/c 500 faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 87 placed at the lower support of the column to measure axial displacement corresponding to each load increment as shown in fig. 5.b. the test was continued until a decrease in the loading capacity with a sudden increase in displacement was shown in the rc columns. since the test is mechanical, load and displacement measurements were recorded manually at each load increment. (a) (b) figure 5. a) eccentricity loading setup, b) installing measurements devices of column specimen 4. tests results 4.1. temperature–time histories two rc columns of each type of columns are exposed to two elevated temperatures which are 400 ºc and 500ºc. the cracks on the surface of the columns after being cooled with air were marked in red colour as shown in the fig. 6. the temperature time history inside the furnace, at concrete surface and at the steel bars were measured for all heated specimens using the type-k thermocouples and shown in fig. 7. it can be noted from this figures that the furnace heating rate were almost similar for all rc columns which is recognized by an abrupt increase in the temperatures up to 180-200 ºc throughout the first ten minutes of heating time, then the rate of heating was significantly decreased to about 4˚c/min up to 350˚c /min. finally, the heating rate decreased more to reach about 1-1.5˚c /min and remained constant up to the end of test. all heated rc columns were cooled down naturally to air temperature. it can be noted that at elevated temperature of 400 ˚c, the difference in temperature between concrete and bar surfaces (δt (c-s)) was 57 ˚c in the nwrc column while in lwrc column, δt (c-s)) was 82 ˚c. further, at elevated temperature of 500 ˚c, the δt (c-s) was 41˚c in the nwrc column while in lwrc column was 132. these results confirm that lwcr columns are more fire endurance than nwrc columns. on the other hand, δt (c-s) is shown in fig. 8. the concrete samples suffer from moisture losses caused by the evaporation of water within the concrete after subjected to extreme temperatures. this approach contributes to a rise in internal tension and hence the emergence of cracks. significant micro-cracks on samples occurred throughout the experiments due to expose to elevated temperatures are 400, and 500 ° c, and one forms of concrete degradation at high temperatures may show local wear (cracks) in the material itself. some fine cracks also occur due to the difference in thermal expansion between concrete and steel. figure 6. the thermal crack pattern for heated columns a) temperature 400 ºc (lwrc) column b) temperature 500 ºc (lwrc) column 88 faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 c) temperature 400 ºc (nwrc) column d) temperature 500 ºc (nwrc)column figure 7. time-temperature histories of lwrc columns and nwrc columns under different elevated temperature a) lwrc b) nwrc figure 8. the difference between the temperature of concrete surface and steel bars surface with time for a) lwrc, b) nwrc columns under different elevated temperatures. 4.2. failure modes and load-displacement relationships the present study consisted of three lwc columns and three nwc columns that were exposed to an eccentricity loading (e/h), which is equal to 0.5, and the first for each group of columns was kept without exposure to temperature as a control specimen, and the other two columns were exposed to high temperatures (400, and 500 °c). exposure of specimens to heat caused moisture loss because of the water evaporation inside the concrete as mentioned previously. this process was considered the main reason for increases in the internal pressures and cracks appear which in turn led to concrete weakening and deterioration. the columns that were heated to 400 and 500 °c experienced a significant increase in the number and width of cracks when loaded compared to the unheated column. the development of cracks with increased load for all specimens was also recorded until failure in columns took place due to crushing in their compression region. in the case of lwrc columns, by applying load on the column, cracks appeared on the tension side of the column at loads of 20 kn, 20 kn, and 10 kn for columns 0.5l20, 0.5l400, and 0.5l500, respectively. moreover, columns exposed to heat are more deformed compared with unheated column due to reduction in compressive strength and tensile strength of concrete. furthermore, flexural compression was the predominant failure mode for all columns at which columns failed by buckling of the columns toward the compression side and crushing of concrete cover as shown in fig. 9. the decreasing in ultimate load capacity for the columns equal to 6.5% and 13.24% at temperature of 400ºc and 500 ºc, respectively compared with control column 0.5l20. also, in the case of nwrc columns, the first cracks of the columns 0.5n20, 0.5n400, and 0.5n500 appeared at loads of 20 kn ,20 kn, and 10 kn, respectively as mentioned in table 4. the crack pattern and failure mode of the rc columns are shown in fig. 10. the fracture of the concrete cover in the columns occurred in different regions of the compression side. for the column 0.5n20 the crushing of concrete cover occurred at mid-height of the column, while in the column 0.5n400 the crushing occurred at the upper part of the mid-height of the column. lastly, the fracture of the concrete cover in the column 0.5n500 was at the lower end of the mid-height of the column. due to the eccentric loading, the investigation revealed that the general failure mode in all test specimens was the buckling of the columns, the crashing of the concrete cover on the compression side, the appearance of cracks on the tension side, and its development towards the compression side. in addition to that, the data showed that the ultimate load capacity of the columns 0.5n400 and 0.5n500 were decreased by about 14.28 % and 28.57%, respectively, compared to the control unheated column 0.5n20 as shown in fig. 11. the decrease in the loading resistance of the columns could be due to degradations in concrete’s strength and reinforcing steel bars when they are exposed to high temperatures. also, from fig. 11a,b, it is shown that the lateral displacement of all columns increases with an increase in the temperature. the reason behind that can be related to the heating, which causes a reduction in column stiffness due to the reduction in the concrete elastic modulus and the reduction in the effective section because of the thermal and cracking expansions of concrete exposed to high temperature. the influence of using lwc on the behavior and fail modes of rc column down different high temperature was investigated in this study. it should be mentioned that both nwrc and lwrc columns were designed to have same ultimate load capacity (600 kn) at ambient temperature. from the test results it has been noted that at elevated temperature the faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 89 ultimate load capacity for nwrc column specimens was less than that of lwrc column specimens with the same conditions. the ultimate load capacity of 0.5l400 column was 254.46 kn, while 0.5n400 column failed at 218.11 kn with a percent of reduction about 14.28 %. similarly, results have shown that 0.5l500 column specimen failed at 181.76 kn while 0.5n500 column specimens failed at 136.27 kn with a reduction of about 23.07%. fig. 12 shows the effect of temperature on the failure load of lwrc and nwrc columns subjected to eccentric loads with eccentricity ratio (e/h=0.5). in addition, fig. 12 illustrates that the reduction at the ultimate load capacity for lwrc heated specimen under 0.5 eccentricity ratios compared to the unheated column is less than the reduction of the ultimate load for the column specimens in nwrc columns because lwc has high resistance to the elevated temperature [28,13,29]. as a result, it can be concluded the efficiency of lwc is much higher when used in high temperature in comparison with nwc. table 4 lists the results of all column samples. figure 9. column specimen failure for 0.5l20, 0.5l400, 0.5l500 figure 10. column specimen failure for 0.5n20, 0.5n400, and 0.5n500 a) lwrc columns b) nwrc columns figure 11. load-lateral and axial deflection of heated and control lwrc and nwrc columns under eccentric loading (e/h=0.5). figure 12. effect of elevated temperature on ultimate load capacity of lwrc columns, and nwrc columns 90 faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 table 4. experimental result for all column specimens. 5. conclusions this paper presented an experimental study to investigate the behavior and failure modes of lwrc columns exposed to elevated temperature under an eccentric load and compared with behavior and failure modes of nwrc columns. six samples of rc columns were tested under an eccentric load with an eccentricity ratio equal to 0.5 after heating two of each type of these with an electric oven and the other columns were kept at the ambient temperature as controls. the behavior of the columns was recorded and evaluated in terms of temperature history and time, load-displacement relationships and failure modes have been recorded and evaluated in the study. the following conclusions can be drawn from the present study: 1. the experimental test results referred to decreasing in the ultimate load capacity with high temperatures where the residual ultimate strength of lwrc columns is equal to 93.5% and 86.76% for 0.5l400 and 0.5l500, respectively compared to the control column 0.5l20 due to the decrease of the modulus of elasticity of steel and concrete with temperature increase. also, the residual ultimate strength of nwrc columns is equal to 85.71% and 71.43% for 0.5l400 and 0.5l500, respectively compared to the control column 0.5n20. from these results it has been noted that the columns with lwc is more efficient compared with columns with nwc. 2. it is noticed that the lateral mid height deflection and axial displacement were increased with the increase of the degree of heating when compared to the control un-heated specimen that due to reduction in stiffness of these columns that produced from heating with high temperatures. 3. crushing in concrete and flexural 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[27] astm, “standard test method for compressive strength of cylindrical concrete specimens,” chủ biên, 2012. column symbol maximum load carrying capacity (kn) percentage decreasing in load carrying capacity (%) ultimate axial deflection (mm) ultimate lateral (mid-height) deflection (mm) p initial cracks (kn) 0.5l20 272.36 0 7.98 14.3 20 0.5l400 254.46 6.5 10.98 14.98 20 0.5l500 236.29 13.24 11.36 17.73 10 0.5n20 254.469 0 10.3 13.12 20 0.5n400 218.116 14.286 12.6 14.76 20 0.5n500 181.763 28.571 13.69 16.88 10 faaiza al-naqeeb and haitham al-thairy /al-qadisiyah journal for engineering sciences 14 (2021) 083–091 91 [28] h. m. al-baghdadi, “effect of high temperature on some properties of light weight concrete,” al-qadisiyah j. eng. sci., vol. 7, no. 2, pp. 176–188, 2014. [29] k. akçaözoğlu and s. akçaözoğlu, “the effect of elevated temperature on the lightweight concrete produced by expanded clay aggregate and calcium aluminate cement,” bilge int. j. sci. technol. res., vol. 1, no. 2, pp. 59–70, 2017. article al-qadisiyah journalfor for engineering sciences 15 (2022) 173–180 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: eng.chem.20.post.8@qu.edu.iq (zainab al-khafajl) https://doi.org/10.30772/qjes.v15i3.830 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. using special additives for decreasing the asphaltene content of missan crude oil zainab talib kasim* and rafid k. abbas deprtment of chemical engineering, coleege of engineering, university of al-qadisiyah, qadisiyah,iraq a r t i c l e i n f o article history: received 10 june 2022 received in revised form 13 august 2022 accepted 20 september 2022 keywords missan heavy oil sara analysis asphaltene content extractive solvent a b s t r a c t in crude oil, asphaltene is one of the fractions that may be dissolved in aromatics like benzene or toluene but cannot be dissolved in alkanes like n-heptane, n-pentane, or petroleum ether (a mixture of alkane compounds). a typical difficulty in oil recovery and refinery processes is asphaltene precipitation, which happens when the oil stream's pressure, composition, or temperature change. so, the stability of asphaltene in crude oil needs to be looked at to find out how likely it is to form asphaltene so that it can be stopped and high treatment costs can be reduced. in the present study, saturate, aromatic, resin and asphaltene (sara) analysis of missan heavy crude oil from the (omar river field) was performed. three additives were used to show their effect on asphaltene at different concentrations and temperatures. the additives included nanoparticles (nano ferric oxide red, nano silica oxide, and a mixture of nano silica and ferric oxide red) and the polymer fiberglass. the concentrations of the additives of the nanoparticles were (200 ppm, 3533 ppm, a867 ppm), (1667 ppm, 6667 ppm, 10000 ppm, and 16667 ppm) and (24000 ppm, 40000 ppm, and 48000 ppm) of nano-silica, ferric oxide red, and a mixture of nano silica and ferric oxide red, respectively, while fofiberglassss, 3733 ppm, 7066 ppm, 10400 ppm, and 13733 ppm) and measured at temperatures (5, 25, and 45oc) the best read i got was when it was used. 4.249% from origin to 6.375% after treating the percentage of asphaltene with 48000 ppm of ferric oxide red and nanoo-silica. ©2022university of al-qadisiyah. all rights reserved. 1. introduction among crude oil components, asphaltene is the most polydisperse, heavy, and polarizable one. according to boussignault, in 1837, it was first characterized as the substance that precipitates out of petroleum once petroleum ether is added [1], n-pentane and n-heptane, as well as petroleum ether, can precipitate these crude oil fractions, but they are still soluble in aromatic solvents like toluene and benzene, [2]. aggregates with 2–6 molecules each are also considered asphaltene. molecules and small colloidal particles make up the aggregates. a precipitation-induced deposit is caused by the accumulation of aggregates into clusters, which are then added together as shown in fig. 1 (hoepfner, 2013). asphaltene precipitation can be modeled in a variety of ways. asphaltenes create micelles' centers and http://qu.edu.iq/ mailto:eng.chem.20.post.8@qu.edu.iq https://doi.org/10.30772/qjes.v15i3.830 https://doi.org/10.30772/qjes.v15i3.830 http://creativecommons.org/licenses/by/4.0/ 174 zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 resins that surround and disperse the oil in the colloidal model, which is based on this idea. figure 1. asphaltene formation, precipitation, and deposition process, (hoepfner, 2013) when the resins are separated from the colloid, aggregation and phase separation will occur, resulting in precipitation, [3]. for dispersion to be stable, a delicate balance must be struck between attracting and repulsive forces: when particles meet, if the attraction forces are stronger, they agglomerate and the dispersion may become unstable. as long as the system is dominated by repulsive forces, it will remain scattered, [4]. in orde to reestablish thermodynamic equilibrium, resin molecules tend to desorb from asphaltene by adding standard alkane liquids such as n-pentane or n-heptane or by adding petroleum ether to crude oil agglomeration is induced by peptizing resin desorption, and with sufficient alkane titration (n-alkane titration), the asphaltene molecules aggregate sufficiently to overcome the brownian forces of suspension, leading to precipitation of the asphaltene molecules, [5]. many researchers, including those listed below, have investigated the stability of asphaltene: analyzed sara analysis by liquid chromatography and applied the cii (oil with higher than 0.9 cii is unstable, and oil with lower than 0.7 cii is stable) and the oliensis spot test (oil with 9 or fewer spot test numbers has been known to be unstable) as an index of asphaltene stability. these three, based on hplc technology, ri and sara fractions were correlated and depended on the difference between ri of the oil and alkane mixture at the asphaltene start point to reveal the crude oil's stability. asphaltene precipitation was found to the ur when the oil's ri was less than 0.05 and greater than 0.06; however, this was not the case for the oil's ri that was greater than 0.06. [6]. to better understand the stability of asphaltene, sara and ri were compared to fan et al's correlation. it was discovered that the oil from alaska was unstable, [7]. sulaimon wt al. [8], showed that fan [9] the correlation given is reliable in estimating the refractive index of crude oil with a maximum absolute deviation of 2.0%. rogel, [10] showed that the composition of crude oil as well as the chemical and structural characterization of asphaltenes, resins, and their relation to asphaltene stability were examined. they discovered connections between crude oil flocculation onsets and asphaltene structural characteristics 2. experimental work 2.1 materials to conduct sara analysis, the heavy crude oil sample is used. the experimental tests were conducted with heavy crude oil samples from missan fields depicted in table 1. table 1. heavy crude oil sample test crude oil from omar river field viscosity (c.p) at ˚5 124.8 viscosity (c.p) at ˚15 84.6 viscosity (c.p) at ˚25 54.3 viscosity (c.p) at ˚35 39.6 viscosity (c.p) at ˚45 api at 60 ˚f density 60 ˚f (gm/cm3) asphalting content wt.% 32.7 23.13 0.915 4.928 2.2 additives nanoparticles the additives include (nanoparticles and polymer) were nano silica oxide, nano ferric oxide red, and polymer fibefiberglassilica: experimental nano silica was obtained from the following sources: (us research nanomaterials, inc). the nanoparticles element analysis as shown in tables 2 and table 3 were of this analysis was provided by the manufacturing company. figure 2 shows the nanosilica used in experimental work. table 2. nanoparticles of silicon oxide with specific characteristics property value purity 99.5(%) average particles size distribution 50 (nm) surface area 180_600 (m2/g) color white bulk density ture density >0.1 (g/cm3) 2.4 (g/cm3) table 3. examination of nanoparticles of silicon oxide sio2 ti ca na fe 99.5% 120 ppm 70ppm 30ppm 20ppm zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 175 figure 2. nanosilica is used in experimental work. ferric oxide: researchers have been fascinated by the unusually strong magnetic properties of iron oxide (fe2o3) for a long time. magnetic storage, catalysis, sensors, and ultra-sensitive magnetic resonance imaging are among its most common applications (mri). researchers are looking into using it instead of the more harmful copper oxychloride for therapeutic purposes because iron oxide is nontoxic. many of the most important fe2o3 nanoparticle properties are listed in the following table 4. figure 3 depicts the nano ferric oxide that was used in the experimentation. table 4: the properties of iron iii oxide nanopowders chemical formula fe2o3 molecular weight 159.69g/mo le appearance (color) red-brown to brown appearance (form) powder average particle size >50nm surface area (40_60)m2/g table 5: properties of fiberglass. type of glass e filament diameter , µm 13 chop length, mm 3, 6, 12 sizing code 562a figure 3. nanoferric oxide is used in experimental work. fiberglass: the fiberglass element analysis, as shown in table 5, was provided by the manufacturing company. figure (4) shows the fiberglass used in experimental work. figure 4. fiberglass used in experimental work. 2.3 instruments and devices 1. the hydrometer for measuring the density and then calculating the api gravity of the crude oil sample. 2. the brookfield dv viscometer (hb) for measuring the dynamic viscosity (μ) crude oil sample dynamic viscosity (μ)em to extract the asphaltene fraction of the crude oil. 2.4 asphaltene content wt. % according to the french institute of petroleum, sara fractionation involves the addition of excess liquid hydrocarbons like n-pentane, nheptane, or petroleum ether to the crude oil with a 40-ml-to-1-g oil ratio, which separates asphaltenes from the crude oil (ip 143). in this study, half the amount was used (20 ml of n-heptane added to 0.5 gm of crude oil), and leaving the mixture for one day by shaking three times during the day to homogenize the mixture and also covering the beaker well with aluminum f oil to prevent volatilization of the solvent (n-heptane) [11]. 176 zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 figure 5. show calculating the percentage of asphaltene. figure 6. separation of asphaltenes from the crude oil. figure 7. shows the deposition of asphalt at the end of the tube. 2.5 filtration process leave the mixture of toped crude oil and n-heptane for one day. then, the mixture was filtrated through a filter membrane of 0.45 µm and left it until figure 8. shows the membrane after filtration. figure 9. shows the membrane after filtration. figure 10. asphaltene content at different temperatures 0 1 2 3 4 5 6 7 0 10 20 30 40 50 a sp h a lt e n e c o n te n t % temperature(˚c) zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 177 complete the filtration process was. this step was shown in figure 8 and figure 9. the weight percent of the precipitated asphaltene on the filter was calculated by eq1. [12]. ar%= (c0-ce)/c0 (1.1) 3. results and discussions 3.1 effect of additives on asphaltene content the impact of various additive types, concentrations, and temperatures on asphaltene content has been studied. a variety of solvents and temperatures are used to treat the feedstock. reduced asphaltene content and the dispersion of asphaltene agglomerates by polar solvents were reduced by these solvents. asphaltene content before addition at different temperatures is shown in figure 10. 3.2 effect of fiberglass on asphaltene content the effect of fiberglass on the asphaltene content was studied at temperatures (5˚c, 25˚c, and 45˚c) and concentrations (3733, 7066, 10400, 13733). effect of fiberglass on the percentage of asphaltene is very high compared to nano-silica, where the highest percentage of reduction reached 2.593% when the concentration increased from 3733 ppm to 13733 ppm at a temperature of 45˚c. and it is considered the second material in terms of its efficiency in reducing asphalt as shown in figure 11. 3.3 effect of nanoparticles on asphaltene content the effect of nanoparticles (nano silica and ferric oxide red) on the asphaltene content was studied at temperatures (5 c, 25 c, 45 c) and concentrations (200, 3533, 6867), (1667, 6667, 10000, 16667), respectively. nanoparticles reduced asphaltene content by 2.194% and 2.427% weight percent, the content of asphaltene is obtained using 16667 ppm and 6867 ppm of each ferric oxide red and nano-silica at temperature 45˚c, as shown in figure 12 and 13 respectively. where these concentrations were studied in three cases, in the first case when the concentration was 24000 ppm, which is equivalent to 6 g, 2 g of nano silica was mixed with 4 g of iron oxide, and the asphaltene content readings were recorded at this concentration, and at 40000 ppm, which is equivalent to 10 g, 4 g of nano silica was mixed with 6 g of iron oxide, and asphaltene content readings were also recorded. as for the last concentration, 48000 ppm, which is equivalent to 4 g of nano-silica with 8 g of iron oxide red, we notice when using the mixture at these concentrations, the asphaltene content by a very large percentage, as shown in the figures below. the results were represented using the minitab program and using a method as shown in the following figures: figure 11. effect fiber glass concentration on asphaltene content figure 12. effect ferric oxide concentration on asphaltene content figure 13. effect nano silica concentration on asphaltene content 178 zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 figure 14. effect mixture of nanoparticles concentration on asphaltene content (case 1). figure 15. effect mixture of nanoparticles concentration on asphaltene content (case 2). figure 16. effect mixture of nanoparticles concentration on asphaltene content (case 3). figure 17. contour plot of asphaltene content after treatment by adding fiberglass figure 18. contour plot asphaltene content after treatment by adding nano ferric oxide figure 19. contour plot asphaltene content after treatment by adding nano-silica zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 179 figure 20. contour plot asphaltene content after treatment by adding a mixture of nanoparticles (case 1) figure 21. contour plot asphaltene content after treatment by adding a mixture of nanoparticles (case 2). figure 22. contour plot asphaltene content after treatment by adding a mixture of nanoparticles (case 3). (a) 5μm zooming (b)1μm zooming (c) 500nm zooming figure 23. asphaltene content at 5˚c sem micrographs analysis showing grain microstructures 3.4 scanning electron microscope (sem) analysis sem analysis provides a micrograph of high resolution for flaws, contamination, and surface fractures. sem analysis is an important investigative tool, where including the use of a focused beam of electrons to produce high magnification and complex images of a sample’s surface topography. as a result, the high magnification and high-resolution micrograph of sem backed the particle size and shape determination [13]. 180 zainab talib kasim and rafid k.abbas/al-qadisiyah journal for engineering sciences 15 (2022) 173–180 (a) 5μm zooming (b)1μm zooming (c) 500nm zooming figure 24. asphaltene content at 25˚c sem micrographs analysis showing grain microstructures sem analysis was used to characterize(asphaltene content at temperatures 5 ̊ c and 25 ̊ c) nanoparticles in the form of powder. by obtaining structural and micrograph images as shown in figures 23 and 24 ( a, b, and c), where micrographs of the particle shape, size, and surface metrology at zooming degrees about 5μm, 1μm, and 500nm respectively. as sem analysis is used to determine particles size, the result unparticle where is due to is this technology, s not enough to create statistical particle number results because it is measured only tens particle hundreds from a large number of particles [3]. 4. conclusions 1. the asphaltene weight percent in the crude oil was determined using the conventional solubility asphaltene detection test using heptane. it was found that the crude oil contained a relatively high concentration of asphaltene which is an indication of the oil being heavy oil since asphaltene is one of the highest molecular weight components of the oil. 2. the highest percentage obtained in reducing the percentage of asphalt when it was used mixture of nanoparticles reduced asphaltene content by 2.195 weight percent, the content of asphaltene is obtained using 48000 ppm using ferric oxide re and nano s ica. 3. the nano-silicaight percent in the crude oil was determined using the conventional solubility asphaltene detection test using heptane. it was found that the crude oil contained a relatively high concentration of asphaltene which is an indication of the oil being heavy oil since asphaltene is one of the highest molecular weight components of the oil. reference [1] ali, a. a., al-jareferences. a and ali, a. a. (2019) “asphaltene stability of some iraqi dead crude oils”, journal of engineering, 25(3), pp. 53–67. doi: 10.31026/j.eng.2019.03.05. [2] chamkalani, a. (2012). correlations between sara fractions, density, and ri to investigate the stability of asphaltene. international scholarly research notices, 2012. [3] devendiran, d. k., & amirtham, v. a. (2016). a review on preparation, characterization, properties, and applications of nanofluids, ds. renewable and sustainable energy reviews, 60, 21-40. [4] fakher, s., imqam, a., & wanas, e. (2018). investigating the viscosity reduction of ultra-heavy crude oil using hydrocarbon soluble low molecular weight compounds to improve oil production and transportation. spe international heavy oil conference and exhibition, [5] fan, t., wang, j., & buckley, j. s. (2002). evaluating crude oils by sara analysis. spe/doe improved oil recovery symposium, [6] hthe oepfner, m. p. (2013). investigations into asphaltene deposition, stability, and structure [7] panuganti, s. (2013). asphaltene behavior in crude oil systems rice university]. [8] powers, d. p. (2014). charact erization and asphaltene precipitation modeling of native and reacted crude oils. [9] rogel, e., leon, o., espidel, y., & gonzalez, y. (2001). asphaltene stability in crude oils. spe production & facilities, 16(02), 84-88. [10] sulaimon, a., & govindasamy, k. (2015). a new correlation for predicting a new asphaltene deposition. spe/iatmi asia pacific oil & gas conference and exhibition, [11] verdier, s. (2005). experimental study and modeling of asphaltenemodelingation caused by gas injection. graduate schools yearbook 2005, 179. [12] yen, a., yin, y. r., & asomaning, s. (2001). evaluating asphaltene inhibitors: laboratory tests and field studies. spe international symposium on oilfield chemistry, [13] zendehboudi, s., shafiei, a., bahadori, a., james, l. a., elkamel, a., & lohi, a. (2014). asphaltene precipitation and deposition in oil reservoirs–technical aspects, experimental and hybrid neural network predictive tools. chemical engineering research and design, 92(5), 857-875. article al-qadisiyah journal for engineering sciences 15 (2022) 142–147 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: abdullah.f.huayier@uotechnology.edu.iq (abdullah huayier) https://doi.org/10.30772/qjes.v15i3.826 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. еxpeгimental investigаtion of сutting cоnditions рarameters on surfаce roughness in aluminum alloys (al-2024) abdullah faraj huayier department of production engineering & metallurgy, university of technology – baghdad – iraq a r t i c l e i n f o article history: received 08 april 2022 received in revised form 06 june 2022 accepted 05 september 2022 keywords: surface roughness metal cutting cutting feed depth of cut a b s t r a c t the purpose of this search is to study the main factors on the surface roughness in (al-2024) using a cnc milling machine for an hss tool with flat end milling. and by using the taguchi experience design method to conserve time and costs. to determine the optimal values of surface roughness using taguchi optimization. we then performed an analysis of variance and regression. confirmation tests were performed to verify work. the cutting process consists of two stages; the first stage is the cutting process in the upper direction of the cutting, using a coolant and dry cutting. the second stage is the cutting process in the lower direction of the cut, using a coolant and dry cutting the results show the best operating condition to obtain the best surface roughness of the product by using the bottom grinding, measuring the surface process surface roughness using the cutting conditions of the cutter (feeding) = 15 mm/min), (cutting depth = 1 mm) and (cutting speed = 37.68 (m/min) surface roughness (ra = 0.17 µm) compared with the other value obtained. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction surface roughness is one of the most important factors in determining product quality. the mechanism underlying surface roughness formation is highly dynamic, complex, and process count on. the factors that influence finished surface roughness in cnc milling operation can be controlled factors (such as spindle speed, feed rate, and depth of cut) and cannot be controlled factor-like (material properties of performance, workpiece, and performance geometry) [1]. the surface roughness has a large role in fatigue strength and wears resistance, surface friction, light reflection, lubricant holding capacity, electrical and thermal contact resistance, appearance, cost, etc. as the high quality of the surface after final grinding and with further automated surface treatment is unnecessary, results in reduced energy consumption and environmental tolerance. however, surface roughness improvement constantly challenges uncertainty in the foretelling model as well as the many impacts parameterized, which can be split into controlled and uncontrolled parameters. [2] determine the appropriate processing conditions by checking the surface roughness of milling aluminum alloy 7075-t6. the taguchi experimental dеsign mеthоd was utilized to save time and cost. and to determine the optimal values of surface roughness using taguchi optimization. analysis of variance and regression anаlysis werе performed. affirmation tests were performed to work. from the results of confirmation tests, it was found that the improvement of surface roughness in milling aluminum alloy 7075-t6 has been swimmingly applied. (neslihan özsoy, 2019). [3] studied the cutting conditions such as cutting feed, cutting depth, and spindle speed on milling of the end of 6061 aluminum to predict the surface roughness. he developed two mathematical models; the first for dehydration and the second for minimum quantity lubrication (mql) fabrication used multiple retreating analyses that predict the surface roughness of aluminum end milling in dry environments and minimum quantity lubrication (mql). an analysis of variance (anova) is used to find the importance of the cut-off parameters on the surface roughness. ojolo sunday joshua http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i3.826 https://doi.org/10.30772/qjes.v15i3.826 http://creativecommons.org/licenses/by/4.0/ abdullah huayier /al-qadisiyah journal for engineering sciences 15 (2022) 142–147 143 and et al. 2015. [4] a study was carried out to improve the surface roughness during processing in grinding al6005a alloy. taguchi-gray relations and anova were used to investigate the effects of the parameters. billy joe et al. 2018 [5]. studied the improvement of surface roughness in the manufacture of gfrp composite. the experiments were planned according to the orthogonal matrix l27 and found the optimal levels of parameters by the method of taguchi. parida ak et al., 2015 [6]. studied the cutting tool, cutting spеed and fеed rаte on the surfаcе roughness of aa7075-t6 in the grinding prоcеss. the results showed that there was an increase in the surface roughness rate with an increase in the feeding rate. but the surfаcе rоughnеss dесreases when сutting spееd incrеаses. tosun n, and et al, 2010 [7]. the processing of austenitic stainless steels is optimized for cut sizes fc, rа, and rаdius nose. experiments were carried out using the taguchi method. günay m, 2013[8]. studied the spindle spееd, feed rаte, axial/radial depth of cut-off radius and nose, and their bidirectional interactions on surface roughness. the taguchi method is used to form aa5083-h36 alloy. they improved using the s/n ratio and anova, pinar am, et al, 2016 [9]. the work aims to show the following points: 1. study of the effect of direction of cutter rotation on cutting conditions (feeding rate, cut cutting depth) 2. the effect of direction of cutter rotation on work surface roughness with different cutting conditions 2. experimental work 2.1 the direction of cutter rotation the cutting direction, as there are two types of cutter movement in the milling process, the first type is up cut milling, which is the rotation of the cutter in the opposite direction to feed the table and is always used traditionally because it gets rid of the backlash between the leadscrew and the machine nut. the second type, is called down cut milling, and the direction of rotation of the cutters is in the same direction as the table feed but it can only be used on machines equipped to be backslash remover or on a cnc milling machine. 2.2 taguchi method the taguchi method was widely applied in the 1960s by genichi taguchi, where it proved to be very successful in improving the quality of industrial products. where researchers increased their interest in this way day after day. especially after reducing the experiments and the ease of application and evаluation. the taguchi method is a method for designing and improving an experiment that depends on parameters design and system design. it is most ordinarily used in the statistical analytics of data composed by quality emphasis systems. therefore, tаguсhi's expеrimеntal dеsign is an excellent method because it determines the optimal integration between different levels for different parameters. researchers have used these experiments to determine and understand a particular system or process. monitoring and analyzing the outputs of this process or system, as well as modifying and analyzing them [11]. the purpose of the taguchi method is to design and improve an experiment as it depends on design parameters. optimization can be defined as the optimum use of the limited resource available. improvement is very important in academic studies. scientists used different methods intending to improve their work [12-14]. 2.3 workpiece material consist of an aluminum alloy block, the dimensions of the block are as follows the length of 220mm, the width of 220mm, and the height of 4mm. table (1) shows the composition chemical of the sample examined. 2.4 machine model a milling machine was used to perform the type of experiment (knuth) model (vector 610) in the university of technology /training center and laboratories. 2.5 cutting tool one type of end milling cutter is used in this work: flat end milling cutter (four flutes). with diameter (8mm) made from high-speed steel. 2.5.1 up milling a-dry machine b-fluid machine figure 1. cutting tools (a) dry machine (b) fluid machine 2.5.2 down milling adry machine b-fluid machine figure 2. cutting tool (a) dry machine (b) fluid machine figure 3. cutting tool 144 abdullah huayier /al-qadisiyah journal for engineering sciences 15 (2022) 142–147 table 1. chemical installation of the al 2024 3. results and discussions 3.1 surface roughness measuring device the american mar surf ps1 device shown in figure (5) has been used and according to the specifications listed in the table (5), it was used to measure the surface roughness. where the parameter to be along the automatic motion (ra) is special to specify because it is easy to use and is widely used as a surface roughness index parameter. figure 4. surface rоughnеss measuring device 3.2 up-cut milling the following are the up-cut milling of dry the machine, and fluid cases respectively. table 4. conditions in the tаguchi mеthоd exреriments сutting sрееd fееd rаtе surface roughness snra1 mean1 18.84 10 4.10 -12.2557 4.10 18.84 15 3.61 -11.1501 3.61 18.84 20 1.52 -3.6369 1.52 18.84 25 1.06 -0.5061 1.06 25.12 10 1.14 -1.1381 1.14 25.12 15 1.24 -1.8684 1.24 25.12 20 0.49 6.1961 0.49 25.12 25 0.49 6.1961 0.49 31.40 10 4.63 -13.3116 4.63 31.40 15 0.58 4.7314 0.58 31.40 20 1.60 -4.0824 1.60 31.40 25 0.87 1.2096 0.87 37.68 10 1.84 -5.2964 1.84 37.68 15 1.87 -5.4368 1.87 37.68 37.68 20 2.72 -8.6914 2.72 25 4.85 -13.7148 4.85 table 2. geometry and properties of cutting tools cutting tool material lеngth of flutе (mm) all length (mm) 4 flutes hss 30 71 si% fe% cu% mn% mg% 0.089 0.188 5.040 0.360 1.420 cr% ni% zn% ti% al% 0.008 0.006 0.028 0.039 bal. table 3. the specifications of (mаr surf psi) term rа 0.03µm tо 12.7µm prоbе head prоbе 20µm travelers lеngth 1.75 mm, 5.6 mm, 17.5 mm, automatically table 5. anоva anаlysis of the signаl-to-nоise rаtio of the surfасе rоughnеss variance source degree of freedom,υ sum оf squаrеs, ss variance, v p (%) cutting speed, vc ( mm/min ) 3 9.39 3.1 28.42 feed rate, f ( mm/min ) 3 4.37 1.1 13.24 error,e 12 ------ total 16 33.02 ---- figure 5. the influence of fеed rаte and cutting spеed on surfаcе rоughnеss for up cut milling on dry machine abdullah huayier /al-qadisiyah journal for engineering sciences 15 (2022) 142–147 145 figure 6. main effects plot for s/n ratios on surface roughness for up cut milling on the dry machine figure. 7. the influence of fеed rаte and cutting spеed on surfаcе rоughnеss for up cut milling on fluid machines figure. 8. main effects plot for s/n ratios on surface roughness for up cut milling on fluid machines. figure 9. the influence of fеed rаte and cutting spеed on surfаcе rоughnеss for down cut milling on dry machine table 6. fluid machining conditions in the tаguchi mеthоd exреriments. сutting sрееd fееd rаtе surface roughness snra1 mean1 18.84 10 3.91 -11.8435 3.91 18.84 15 1.40 -2.9226 1.40 18.84 20 0.90 0.9151 0.90 18.84 25 0.82 1.7237 0.82 25.12 10 5.75 -15.1934 5.75 25.12 15 4.62 -13.2928 4.62 25.12 20 0.87 1.2096 0.87 25.12 25 1.35 -2.6067 1.35 31.40 10 5.75 -15.1934 5.75 31.40 15 0.48 6.3752 0.48 31.40 20 0.29 10.7520 0.29 31.40 25 1.96 -5.8451 1.96 37.68 10 5.03 -14.0314 5.03 37.68 15 0.33 9.6297 0.33 37.68 20 0.63 4.0132 0.63 37.68 25 1.08 -0.6685 1.08 figure 10. main effects plot for s/n ratios on surface roughness for down-cut milling on dry machine table 7. anоva anаlysis of the signаl-to-nоise rаtio of the surfасе rоughnеss variance source degree of freedom,υ sum оf squаrеs, ss variance, v p (%) cutting speed, vc ( mm/min ) 3 5.15 1.72 8.22 fееd rаte,f ( mm/min ) 3 47.40 15.80 75.71 error,e 12 ------ total 16 62.60 ---- 146 abdullah huayier /al-qadisiyah journal for engineering sciences 15 (2022) 142–147 table 9. fluid case: anоva anаlysis of the signаl-to-nоise rаtio of the surfасе rоughnеss. variance source degree of freedom,𝛖 sum оf squаrеs, ss variance, v p (%) cutting speed, vc ( mm/min ) 3 9.62 3.21 37.93 fееd rаte,f ( mm/min ) 3 0.55 0.18 2.16 error,e 12 ------ total 16 25.36 ---- figure 11. the influence of fеed rаte and cutting spеed on surfаcе rоughnеss for down-cut milling on fluid machines figure 12. main effects plot for s/n ratios on surface roughness for down-cut milling on fluid machines table 11. anova for the signal-to-noise ratio analysis of surface roughness variance source degree of freedom,𝛖 sum of squares, ss variance, v p (%) cutting speed, vc ( mm/min ) 3 0.3443 0.1148 26.81 fееd rate, f ( mm/min ) 3 0.1127 0.0376 8.77 error,e 12 ------ total 15 1.2841 ---- figures (6, 8, 10, and 12) indicate. the cutting conditions directly affect the surface roughnеss, as in the case of an increase in the feeding rate and a constant cutting speed, we notice that the average surface roughnеss increases, as well as in the case of an increase in the cutting speed and with table 8. dray case: machining conditions in the tаguchi mеthоd exреriments сutting sрееd fееd rаtе surface roughness snra1 mean1 18.84 10 0.60 4.4370 0.60 18.84 15 0.70 3.0980 0.70 18.84 20 0.38 8.4043 0.38 18.84 25 0.44 7.1309 0.44 25.12 10 0.87 1.2096 0.87 25.12 15 0.36 8.8739 0.36 25.12 20 0.49 6.1961 0.49 25.12 25 0.74 2.6154 0.74 31.40 10 0.66 3.6091 0.66 31.40 15 1.35 -2.6067 1.35 31.40 20 0.62 4.1522 0.62 31.40 25 0.22 13.1515 0.22 37.68 10 0.27 11.3727 0.27 37.68 15 0.17 15.3910 0.17 37.68 20 0.49 6.1961 0.49 37.68 25 0.33 9.6297 0.33 table 10. machining conditions in the tаguchi mеthоd exреriments сutting sрееd fееd rаtе surface roughness snra1 mean1 18.84 10 0.53 5.5145 0.53 18.84 15 2.10 -6.4444 2.10 18.84 20 0.53 5.5145 0.53 18.84 25 1.56 -3.8625 1.56 25.12 10 1.11 -0.9065 1.11 25.12 15 0.59 4.5830 0.59 25.12 20 0.83 1.6184 0.83 25.12 25 1.12 -0.9844 1.12 31.40 10 5.05 -14.0658 5.05 31.40 15 1.07 -0.5877 1.07 31.40 20 3.11 -9.8552 3.11 31.40 25 2.35 -7.4214 2.35 37.68 10 1.08 -0.6685 1.08 37.68 15 3.69 -11.3405 3.69 37.68 20 2.48 -7.8890 2.48 37.68 25 0.79 2.0475 0.79 abdullah huayier /al-qadisiyah journal for engineering sciences 15 (2022) 142–147 147 a constant feeding rate, we also notice that there is an increase in the surface roughness rate. through taguchi method, the best cutting conditions were predicted to obtain the best surface roughness results, the best surface roughness is in down cut milling, by using fluid, measuring the surface roughness of the operating surfaces using cutting conditions for the cutter (feed = 15 mm/rev, depth of cut = 1 mm and cutting speed = 37.68 (m/min)) the surface roughness (ra) was = (0.17 µm) compared with other values obtained. and that the most influential factor through the anova is the cutting speed. it is worth mentioning that in down milling, the cutting tool is fed with the trend of rotation. references [1] zhai, c.; y.; hanauer, d.; proust, g.; restraint, d."the role of surface structure in normal contact stiffness" (2016). [2] asm metals handbook vol. 2, properties and selection of nonferrous alloys and special purpose materials, asm international. [3] neslihan özsoy, “experimental investigation of surface roughness of cutting parameters in t6 aluminum alloy milling process” vol. 5-no.3 (2019) pp. 105111. [4] ojolo sunday joshua1,*, money ochuko david1, ismail oluwarotimi sikiru2, “ experimental investigation of cutting parameters on surface roughness prediction during end milling of aluminium 6061 under mql (minimum quantity lubrication), journal of mechanical engineering and automation 2015, 5(1): 1-13. [5] pillai ju, sanghrajka i, shunmugavel m, muthuramalingam t, goldberg m, littlefair g, “optimisation of multiple response characteristics on end milling of aluminum alloy using taguchi-grey relational approach” measurement 124, 291-298, 2018 doi: 10.1016/j.measurement.2018.04.052. [6] parida ak, routara bc, bhuyan rk, “surface roughness model and parametric optimization in the machining of gfrp composite: taguchi and response surface methodology approach” materials today: proceedings 2, 3065-3074, 2015. [7] tosun n, kuru c, altıntaş e, erdin oe, “investigation of surface roughness in milling with air and conventional cooling method” journal of faculty of engineering and architecture of gazi university 25,141-146, 2010 [8] günay m, “optimization with taguchi method of cutting parameters and tool nose radius in the machining of aisi 316l steel” journal of the faculty of engineering and architecture of gazi university 28, 437444, 2013. [9] pinar am, filiz s, ünlü bs, “a comparison of cooling methods in the pocket milling of aa5083-h36 alloy via taguchi method” the international journal of advanced manufacturing technology 83, 1431–1440, 2016 doi: 10.1007/s00170-015-7666-1. [10] groover, p. m., "fundamentals of modern manufacturing", wiley inc., 2. international edition. [11] montgomery dc, “design and analysis of experiments”, wiley, new york, 2007. [12] precious a, “optimization of circular antenna arrays using a differential search algorithm” acta physica polonica a 128,7-8, 2015 doi: 10.12693/aphyspola.128.b-7. [13] ozsoy m, kurnaz c, “an optimization study of a hydraulic gear pump cover with finite element method” acta physica polonica a 132, 944-948, 2017 doi: 10.2693/aphyspola.132.944. [14] filiz i̇h, olguner s, evyapan e,” a study on optimization of planetary gear trains” acta physica polonica a 132:728-733, 2017. 4. conclusion 1. the best surface roughnesses are in down cut milling cut, using fluids, and at a higher cutting speed, where we notice an improvement in the surface roughness values. 2. in down milling, the thickness of the chips decreases from the beginning of cutting, gradually reaching zero at the end of cutting. these forbid the edge prevents rubbing and polishing on the surface before engaging in cutting. 3. the best surface roughness results were obtained, and the best shipping conditions were predicted by the taguchi method. this is done by designing experiments based on special design criteria. therefore, taguchi's method is excellent because it determines the optimal integration between different levels for different parameters. 4. using anova, it was shown to us that cutting speed is the most influential factor in surface roughness. [15] tosun n, kuru c, altıntaş e, erdin oe, “investigation of surface roughness in milling with air and conventional cooling method” journal of faculty of engineering and architecture of gazi university 25,141-146, 2010 [16] günay m, “optimization with taguchi method of cutting parameters and tool nose radius in the machining of aisi 316l steel” journal of the faculty of engineering and architecture of gazi university 28, 437444, 2013. [17] pinar am, filiz s, ünlü bs, “a comparison of cooling methods in the pocket milling of aa5083-h36 alloy via taguchi method” the international journal of advanced manufacturing technology 83, 1431–1440, 2016 doi: 10.1007/s00170-015-7666-1. [18] groover, p. m., "fundamentals of modern manufacturing", wiley inc., 2. international edition. [19] montgomery dc, “design and analysis of experiments”, wiley, new york, 2007. [20] precious a, “optimization of circular antenna arrays using a differential search algorithm” acta physica polonica a 128,7-8, 2015 doi: 10.12693/aphyspola.128.b-7. [21] ozsoy m, kurnaz c, “an optimization study of a hydraulic gear pump cover with finite element method” acta physica polonica a 132, 944-948, 2017 doi: 10.2693/aphyspola.132.944. [22] [14] filiz i̇h, olguner s, evyapan e,” a study on optimization of planetary gear trains” acta physica polonica a 132:728-733, 2017 doi: 10.12693/aphyspola.132.728 article al-qadisiyah journal for engineering sciences 14 (2021) 144–149 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: rod.post05@qu.edu.iq(zainab a. al-kareawi ) https://doi.org/10.30772/qjes.v14i2.766 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. alternatives to enhance traffic conditions at u-turn sites zainab a. al-kareawia* and jalal t. al-obaedia a road and transportation department, university of al-qadisiyah, iraq. basst.prof. ,university of al-qadisiyah, college of engineering, iraq. a r t i c l e i n f o article history: received 18 july 2021 received in revised form 26 august 2021 accepted 26 august 2021 keywords: traffic simulation, vissim, u-turn a b s t r a c t traffic simulation models play a major role in allowing traffic engineers to assess complex traffic situations such as u-turn section. such models help in proposing solutions and proposing alternative scenarios without committing too many expensive resources and this models are necessary to implement alternative strategies in the field. simulation traffic models can significantly improve the quality of road network planning and design in urban areas. according to filed observation, the u-turn movement cause traffic congestion at both origin and distention (opposite) roads. this study introduced many alternatives to enhance the movement at u-turn section. these alternatives have been tested by using simulation models. the ptv vissim software was used to development the models. this development model has been calibrated and validated by using filed data collected from al-diwaniyah city, iraq. the results show from the simulation results are in good agreement with the real data. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction the u-turn movement is defining as the turning movement that is implemented at u-shape and it aim to travel to the opposite side. this area represents unsafe and cases traffic congestion in both origin and destination (opposing) roads [1, 2]. there are many types of u-turn section. the median u-turn is the most common type that allow traffic to make the left turn through the median by using special path in the multilane roads. the other types including the uturn at intersection, roundabout [3, 4]. the u-turn movement is more dangerous and having high accident since this movement is not control by traffic signals and it is dependent on the gap acceptance from drivers[5, 6] . if the gap is not enough to make the uturn and turning to the opposite side, the accident accrues due to the conflict with the opposite traffic [4]. the turning vehicle should be reducing their speed near the u-turn section and stop at the u-turn section if the available gap is not enough to make the u-turn movement. when the gap is enough, the vehicle is executing the turning process to the opposite side. the geometric layout of u-turn section may have the auxiliary lane (storage lane) used to story the traffic that waiting unite the enough gap is providing to turn to the opposite direction. the anther used of auxiliary lane as a deceleration lane to reduce speed of turning vehicles and not cause accidents. figure 1 show the geometric layout of u-turn section with and without auxiliary lane. during the past two decades, the u-turn movement used a treatment in intersections by replacing the direct left turn by right plus u-turn. the advantage of used this treatment including travel and delay could be less when the traffic volume in major street is high or moderate, the capacity of http://qu.edu.iq/ mailto:rod.post05@qu.edu.iq(zainab https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ zainab a. al-kareawi, jalal t. al-obaedi /al-qadisiyah journal for engineering sciences 14 (2021) 144–149 145 a u-turn movement at the median opening is much higher than the capacity of a direct left turn movement, and right turns plus u-turns have fewer conflicts than direct left turns [7]. traffic simulation models play a major role in allowing traffic engineers to assess complex traffic situations. this models help in proposing solutions and proposing alternative scenarios without committing too many expensive resources that are necessary to implement alternative strategies in the field. simulation traffic models can significantly improve the quality of road network planning and design in urban areas[8] there are little studies of the alternative to enhance the movement at u-turn section. the speed humps are being used in many countries in the world as a technique to calm the traffic and make the turning process is easy and reduce the accident [9, 10]. al-obeadi (2019) studied the effect of speed hump on the (ats) by the turning vehicles and the results show the used of speed hump can reduce the (ats). al-jameel(2014) [11] suggested the new design for u-turn section and the result shown this design can increase the capacity of u-turn section. rhaptyalyani h. della and others (2015)[2], study the effect of used new design for u-turn section on the capacity, degree of saturation, and queue length and traffic delay. the new model including the use of roundabout and the second models used fly over uturn. the results showed the used of second models give best perforce and reduced the delay and queue length, and increased the capacity. the basic objective of the current research is to investigate the effect of using different scenarios to improve the movement at the median u-turn section by using ptv vissim 5.10 microsimulation software. the travel time is used to compares between the difference alternatives. these scenarios including studying the effect of using traffic control on the through, opposing, and merging traffic, the effect of using speed humps in the opposing direction, increasing number of lanes and finally applying “jack handle” configuration on the u-turn site. figure 1:the geometric layout of median u-turn section. 2. methodology the methodology of this research including the site selection, data collected and analyze, model building, calibration and validation for the model building and testing different scenarios to enhance the movement at the uturn section. the site for the u-turn section is selected from al-diwaniyah city, iraq. the video recording is used to collect data and the through, opposite, merge1, merge2 volumes and average queue length is excavation for data collected. traffic simulation is applied using ptv vissim development the u-turn model. the model has been calibrated and validated based on real traffic data as published in the authors previous research work[12] .the developed model use to study the effect of applying the alternatives in order to enhance traffic conditions at u-turn sites. 3. data collection in order to achieve the objective of the research, the data should be collected. there are many methods of data collected. according to the information required in this study the video recording is the properly method to collected data. as discussed above, the parameters extracted form the data collected including the through volumes “refers to the through traffic volumes in the direction of merge 1”, the opposing volume” refers to the traffic volumes opposing to traffic volumes at merge 1” while merge 1 “refers to the u-turn direction with higher volumes than the another direction merge 2”and the average queue length that generate prior the u-turn section. the speed is collected by using the radar speed gun. the speed is measurement at the three location. the location no.1 at (100 m before the u-turn section) to investigate the behaviour of drivers near the u-turn sections. location no.2 at the u-turn section and the location no.3 at (100m before u-turn in the opposite direction) to investigate the behaviour of drivers near the u-turn sections. table (1) illustration the range of traffic flow and average queue length for data collected and the mean for the measure speed. table 1 the range of traffic flow and average queue length for data collected and the mean for the measure speed traffic volumes for each direction avg. queue length veh mean speed for each location through veh/hr opposite veh/hr merg1 veh/hr merg2 veh/hr no.1 km/hr no.2 km/hr no.3 km/hr 7801080 6721392 372648 96216 2-5 51.31 27.96 47.53 4. model development this section describes the model development and the calibration and validation process for the development model. the vissim models were built by adding link (to draw the road) and connecter (to draw the uturn), use “yield priority” to make the turning vehicle wait until enough gap is available. the hump speed is select by adding “reduce speed area”. the traffic volume for each direction is entered to the networks by using the” vehicle input tool” the priorities of movements were applied by introducing “conflict area” which give the priority of opposing traffic. after the model building, the calibration and validation process are done to represent the real data. the results show the development models are representing the real. 5. models applications as described above, the calibrated and validated simulation models using ptv vissim was used in this research work. many scenarios have been examined including the use of traffic signal, the use of speed humps, increase the number of lane and finally applying the “jack handle” shape as shown in figure 2 below. the travel time is used to examine the effect of applying these scenarios for the nearby sections. the travel times is defining as the difference in time between the vehicles arriving at the beginning of the section and the time the vehicles leaving the same section. figure 2 illustration the location of travel time section. according to traffic volumes in the real situation, the traffic volumes are used in these application are similar to the real (1000 veh/hr for the through direction), (500 veh/hr for merge1 direction), (1200 veh/hr for opposite direction) and (100 veh/hr for the merge2 direction). a/ median u-turn b/u-turn with auxiliary lane 146 zainab a. al-kareawi, jalal t. al-obaedi /al-qadisiyah journal for engineering sciences 14 (2021) 144–149 figure 2: the location of travel time section 5.1 the effect of using traffic control the traffic control was usually used in intersections if that was warranted and the use of such signals at other sites such as (u-turn sites) needs to be examined before been applied. theoretically, the benefit of using traffic controls at u-turn section were to increase the safety by avoiding conflicting points. however, the effect of using traffic signals at such sites on capacity or travel time should also examined. in this work, two signals were examined using traffic simulations, one for merging traffic and the second is for opposing traffic as shown in figure 3. figure 3: the traffic signal location. different green times with 60 second cycle length have been examined as shown in table 2 below. figure (4) show the travel time for sec.1, sec.2, sec.3, sec.4, and sec.5 for all case of traffic signal. for sec.1 (before traffic signal in through direction) when the green time is high, the travel time is reducing. the travel time begin increase when the green time is decrease. for sec.3 (before traffic signal in opposite direction), the travel time for all cases (a, b, c, d) is higher than the normal case since the red time is higher than the green time. for sec.5, the travel time for all cases (a, b, c, d) is lower than the normal cases. for sec.2 and sec.4, the travel time is no effect when using the traffic signal. table 2 traffic control times. figure 4: the travel times with used of traffic control. 5.2 the effect of using speed humps speed humps is one of the most traffic calming that produce significant reduction for speeds of traffic. in this study, the speed hump is placed in opposite direction to reduce the speed of vehicles that conflict with the turning vehicles to ease the turning process. such speed humps are usually located upstream of the u-turn sites as show in figure (5). figure 5: the speed humps location. different speeds for opposing traffic have been tested to simulate the effect of humps on opposing traffic speeds and to examine the effect of that on merging traffic. table (4) shows the speed of vehicles at hump. figure (6) traffic control data case cycle length (s) for through traffic for opposite traffic green time(s) red time (s) green time (s) red time (s) case a 60 50 10 10 50 case b 60 45 15 15 45 case c 60 40 20 20 40 case d 60 35 25 25 35 0 5 10 15 20 normal case case a caseb case c case d t ra v e l ti m e ( se c) traffic signal time (sec) sec.2 0 50 100 150 200 250 normal case case a caseb case c case d t ra v e l ti m e ( se c) traffic signal time (sec) sec.3 0 10 20 normal case case a caseb case c case d t ra ve l ti m e ( se c) traffic signal time (sec) sec.4 0 10 20 30 40 normal case case a caseb case c case d t ra v e l ti m e ( se c) traffic signal time (sec) sec.5 15 17 19 21 23 25 27 normal case case a caseb case c case d t ra v e l ti m e ( se c) traffic signal time (sec) sec.1 zainab a. al-kareawi, jalal t. al-obaedi /al-qadisiyah journal for engineering sciences 14 (2021) 144–149 147 shows the travel time results for sec.1, sec.2, sec.3, sec.4, and sec.5 for all case of speed hump. the used of the speed humps can significantly effect to reduce the travel time for the turning vehicles and make the u-turn process is easy. for sec.1, the use of speed hump decreases the travel time and when the speed of vehicles at the hump increase the travel time also increase. for sec.3, the used of speed hump at the opposite direction increase the travel time since the speed in the section is lower due to the use of hump and when the speed of vehicles at hump increase the travel time is decrease. for sec.5, when the speed of vehicles in humps increase the travel time also increase since the speed in main street (opposing direction) is increase and the turning vehicles should be waiting unite the enough gap is providing. for sec.2 and sec.4, the travel time is not effect when using the speed hump. table 3 the speed of traffic at humps figure 6: the effect of speed hump on the travel time. 5.3 the effect of increasing number of lanes in al-diwaniyah, most of multilane roads having three lanes for each direction but however, one of these lanes is usually utilized as on line parking. this section examines the effect of increasing the no. of lanes of the travel time of the through, opposing, merging directions by preventing such on line parking. figure (7) shown the travel time for sec.1, sec.2, sec.3, sec.4, and sec.5 for using two lanes and three lanes. the results show that the increase the number of lanes have significantly reduced the travel time in (sec.1, 5) because the capacity of two lanes is lower than the capacity of the three lanes and (sec.2,3,4) are not effect. from that, it should be recommended to prevent vehicles to stop near the u-turn section for the purpose of reducing congestion and facilitating the turning process. case no. the speed of vehicles at hump normal case 50 (km/hr) case a 5 (km/hr) case b 12 (km/hr) case c 20 (km/hr) case d 30 (km/hr) 0 10 20 30 40 5 km/h 12 km/h 20 km/hr 30km/hr 50km/hr t r a v e l ti m e ( se c ) speed at ahump (km/hr) sec.1 0 5 10 15 20 5 km/h 12 km/h 20 km/hr 30km/hr 50km/hr t ra v e l ti m e ( se c) speed at ahump (km/hr) sec.2 0 50 100 150 200 5 km/h 12 km/h 20 km/hr 30km/hr 50km/hr t r a v e l ti m e ( se c ) speed at ahump (km/hr) sec.3 0 5 10 15 20 5 km/h 12 km/h 20 km/hr 30km/hr 50km/hr t r a v e l ti m e ( se c ) speed at ahump (km/hr) sec.4 0 10 20 30 40 twolanes three-lanes t ra v e l ti m e ( se c) number of lanes per direction sec.1 0 5 10 15 20 twolanes three-lanes t ra v e l ti m e ( se c) number of lanes per direction sec.2 0 5 10 15 20 twolanes three-lanes t ra v e l ti m e ( se c) number of lanes per direction sec.3 0 5 10 15 20 twolanes three-lanes t ra v e l ti m e ( se c) number of lanes per direction sec.4 0 10 20 30 40 50 60 70 5 km/h 12 km/h 20 km/hr 30km/hr 50km/hr t ra v e l ti m e ( se c) speed at ahump (km/hr) sec.5 148 zainab a. al-kareawi, jalal t. al-obaedi /al-qadisiyah journal for engineering sciences 14 (2021) 144–149 figure 7: the effect of increase no. of lanes of the travel time. 5.4 the effect of using jack handles the geometric design of jack handle is required a spacious place on the side of the road near the u-turn section. no lane uses nearby the site selection. the jack handle treatment cannot use in crowded cities with urban buildings on the sides of road. it might be effective on external roads that contain empty spaces on the sides of the road. figure (2) shows the u-turn model with jack handle. figure (8) shown the result of using jack handle. figure 8: the effect of using jack handle on the travel time. in this study, the gap is take (2.5 sec.).this gap take from the calibration and validation processes . for sec.1 (before jack handle in through direction), the used of jack handle increase the travel time for this section as compared to the normal section. for sec.5 (turning direction), the travel time for normal section is lower than the travel time when using jack handle because the turning vehicles in jack handle should wait unit the enough gap is providing in the through and opposite direction. on the other hand, the turning vehicles in normal case wait unite the enough gap is providing in opposite direction only. for sec.2, sec.3, and sec.4, the travel time is not effect when using the jack handle treatment. finally, the used of jack handle is not effective to enhance the movement at the u-turn section. 5.5 the effect of using special lanes for turning vehicles the used of special lane (see figure 2) for the turning vehicles is an effective way to increase the capacity of u-turn section as well as making the u-turn movement safer as a result of eliminating conflict points during the turning process. this section examines the effect of allocating of a special u-turn path through both directions. figure (9) shows the results of the effect of using special lane for turning vehicles on the travel time. the use of special lane for the turning vehicles has a significant effect to reduce the travel time for the turning vehicles. for sec.3,4, the travel time is not effect. for sec.5, the travel time is reducing when using the special lane for turning vehicles since the turning vehicles are not effect by the opposite volume and turn directly without waited to provide the enough gap. as well as, the (500 veh/hr) is the input turning volumes and the output volumes after the run is (400 veh/hr) in normal case and (528 veh /hr) in used of special lane for turning veh case. this result lead to the capacity of u-turn also increase. 0 10 20 30 40 50 60 70 twolanes three-lanes t ra v e l ti m e ( se c) number of lanes per direction sec.5 0 20 40 60 80 100 normal case jack handle case t ra v e l ti m e ( se c) treatment type sec.1 0 5 10 15 20 normal case jack handle case t ra v e l ti m e ( se c) treatment type sec.2 0 5 10 15 20 normal case jack handle case t ra v e l ti m e ( se c) treatment type sec.3 0 5 10 15 20 normal case jack handle case t ra v e l ti m e ( se c) treatment type sec.4 0 20 40 60 80 100 120 140 160 180 normal case jack handle case t ra v e l ti m e ( se c) treatment type sec.5 0 5 10 15 20 normal case special lane for turning vehicles case t ra v e l ti m e ( se c) treatment type sec.3 0 5 10 15 20 normal case special lane for turning vehicles case t ra v e l ti m e ( se c) treatment type sec.4 zainab a. al-kareawi, jalal t. al-obaedi /al-qadisiyah journal for engineering sciences 14 (2021) 144–149 149 figure 9: the effect of using special lane for turning vehicle on the travel time. 6. conclusions this paper used vissim microsimulation software to development model for the u-turn section and test different scenarios to enhance the movement at u-turn section. the video recording was used to collect data for aldiwaniyah city, iraq. the calibration and validation process were done for model development to represent the real data. after this stage, the models used to test different alternatives and the result shown the ability of use vissim software to model the complicated section such as u-turn section. the following conclusions could be highlighted. • the use of traffic signal at u-turn section may enhance traffic conditions at u-turn sites if appropriate signal timings is used. • the use of speed hump in the opposite direction causes the reduction of travel time for the turning vehicles since the driver at the speed hump should reduce their speed. in addition, when the speed of the vehicles at a hump is increased, the average travel time for turning is increase but the average travel time for opposing traffic also decrease. • the increase the number of lanes have significantly reduced the travel time in turning vehicles. therefore, it should be recommended to prevent vehicles to stop near the u-turn section for the purpose of reducing congestion and facilitating the turning process. • the use of jack handle layout has increased the travel time for sections and therefore, such layout has not recommended based on this study results. • the used of special lane for the turning vehicles has significantly reduced the travel time for the turning vehicles. references 1. combinido, j.s.l. and lim, modeling u-turn traffic flow. 2010. 389(17): p. 3640-3647. 2. della, r.h., j. arliansyah, and riga, traffic performance analysis of u-turn and fly over u-turn scenario; a case study at soekarno hatta road, palembang, indonesia. 2015. 125: p. 461-466. 3. al-obaedi, investigation the effect of speed humps on merging time of u-turn traffic. 2019. 10(1): p. 1-4. 4. al-obaedi, simulating the effect of speed humps on the u-turn traffic. 2019. 32(12): p. 1773-1780. 5. meel, i.j.a.t.j., the optimal design of u-turns on thai highways. 2014. 7(1): p. 21-32. 6. meel, i.p., et al., safety impact of application of auxiliary lanes at downstream locations of thai u-turns. 2017. 41(1): p. 1-11. 7. yang, x., et al. the gap acceptance study of u-turn at median openings. in ite 2001 annual meeting and exhibitinstitute of transportation engineers (ite). 2001. 8. detemple, j., et al., simulation methods for optimal portfolios. 2007. 15: p. 867923. 9. binti bachok, r. and k. sarah. residents’ perceptions on the effectiveness of road humps in improving malaysian residential environments. in proceedings of the 2nd world congress on civil, structural, and environmental engineering. 2017. citeseer. 10. organization, w.h., global status report on road safety 2015. 2015: world health organization. 11. al-jameel, contribution to the u-turn design at median openings in iraq: alnajaf city as a case study. 2014. 6(1). 12. al-kareawi, z.a. and j.t. al-obaedi. simulation of u-turn traffic based on vissim and paramics micro simulation. in journal of physics: conference series. 2021. iop publishing. 0 20 40 60 80 normal case special lane for turning vehicles case t ra v e l ti m e ( se c) treatment type sec.5 article al-qadisiyah journal for engineering sciences 15 (2022) 202–209 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mark6ge@gmai.com(ali a.oudah) https://doi.org/10.30772/qjes.v15i3.838 2411-7773/© 2022 university of al-qadisiyah. all rights reserved . this work is licensed under a creative commons attribution 4.0 international license. semisolid state sintering behavior of aluminum-stainless steel 316lnickel composite materials in powder metallurgy ali a. oudah*, mahmoud a. hassan, and nabeel almuramady department of mechanical engineering, college of engineering, university of al-qadisiyah, al diwaniyah, iraq a r t i c l e i n f o article history: received 01 july 2022 received in revised form 07 august 2022 accepted 18 september 2022 keywords: alu. alloy 316l sintering powder milling a b s t r a c t powder metallurgy (pm) is a primarily used because of its relatively close capability and cost -achievement ratio. the automotive industry is considered a major market for the powder metallurgy industry, as it necessitates products having superior mechanical or part of the implementation on a global level. pm technology is undergoing considerable changes in manufacturing and materials research as automobile technologies transitions beyond classic gasoline powered vehicles to new energy vehicles. changes in automobile technologies has created both obstacles and opportunities for pm, as outlined in this article. the mechanical properties of fgm (al-ni-steel) sample were investigated using hardness and tensile tests. transmission electron microscopy (sem) and x-ray diffraction instrument analysis were also used to analyze the microstructure of fgms in detail by using xpert analytical program. tensile specimens were made from sintered cylindrical rods with a length of 150 mm size with diameter of 10 mm. tensile samples with the circular section size of 1cm and a length of 3 cm are machined according to astm e -8m. homogeneous beams comprising varied weight fractions of al (aluminum), ni (nickel), and 316 steel are fabricated and tensile tests are performed to estimate the elastic modulus of horizontally layered functionally graded (fgms) rods. each homogenous layer's density is also calculated experimentally. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction materials are constantly being produced, ranging from iron to pure metals to composite materials that are currently in use. fig. 1 [1] depicts the evolution of materials from the bronze age to the current day and into the future. pure metals have a relatively restricted use since real-world applications may demand properties that a single metal cannot give. alloys are often stronger and more versatile than pure metals. the earliest alloy produced in 4000 bc was bronze, which is a copper-tin alloy (bronze age). since then, many metal and non -metal mixes have been explored to combine the strengths of numerous materials according to functional requirements. the volume or weight percentage, configuration, and geometry of changes in phase distribution can all be converted. the change in volume fraction might occur in any direction or immediately over the full thickness of the component (such as the coordinates of the plate or beam). because of its modest expansion capacity, the ceramic area has high heat http://qu.edu.iq/ mailto:mark6ge@gmai.com(ali https://doi.org/10.30772/qjes.v15i3.838 https://doi.org/10.30772/qjes.v15i3.838 http://creativecommons.org/licenses/by/4.0/ ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 203 resistance. ductile metal components can withstand stress caused by rapid temperature fluctuations in a short period of time[2],. the volume or weight percentage, configuration, and geometry of changes in phase distribution can all be converted. the change in volume fraction might occur in any direction or immediately over the full thickness of the component (such as the coordinates of the plate or beam). because of its modest expansion capacity, the ceramic area has high heat resistance. ductile metal components can withstand stress caused by rapid temperature fluctuations in a short period of time [3], [4]. composite materials provide a higher strength-to-stiffness ratio, better fatigue, wear, and corrosion resistance, and higher dependability than pure or alloyed metals. figure 1. from bronze to fgms, material progress has been continuous despite these benefits, composite materials have an abrupt shift of characteristics at the interface, which can lead to components failure by (delamination) [5]under excessive operating conditions in which delamination is a failure mode in which a material cracks into layers. delamination may occur in a number of materials, such as multilayer composites [6] and concrete. layer separation may cause failure in metals such as steel rolling[7],[8]. and polyester and metals created by 3 dimensional printing,[3]. delamination of coating materials including such paints and films from of the upon is also a possibility. the adhesion between layers in laminated composites frequently breaks first, leading layers to split. [4] in glass(fiber) reinforced plastic (grp), for example, plates of strong reinforcing (such as fiberglass) are linked together with a considerably weaker matrix material (e.g., epoxy). in particular, loads applied orthogonally to the high potency layers, and shear stresses could indeed cause the polymer structure to fracture or the reinforcement materials to split from the composite material. the purpose of this work is to discuss functionally gradient materials (fgms), their kinds, and manufacturing processes. fgms are also studied using solid free form fabrication (sff) methods. fgm is a revolutionary hybrid material that tailors material properties to individual application requirements, revolutionizing materials research. nevertheless, there are still roadblocks in the way of achieving this objective[9]. other challenges include a lack of data obtained, as well as technology such as mass production to properly leverage this approach., and so on, in addition to the primary cost issue. many studies on successful manufacturing methods for fgm are already underway; nevertheless, there are still a number of challenges that need to be addressed with these emerging technologies[10]. more research is required to build a suitable database, which will include detailed characterization of fgms and the development of prediction models for proper process control, allowing for the creation of more effective fgms. an effective feedback system is essential in fully formed automated manufacturing processes; hence, for total process control improvement, extensive research is required[11]. pm is very effective for fgms manufacture; nevertheless, various challenges, including as size and shape limitations, powder cost (which is more than castings material), complexity in producing a continual gradient, & sintering defect, still need to be addressed [12]. 2. materials and methods nickel, steel316l and aluminum powders were used as raw materials to make the fgms in this section[13]. because reason steel 316l was utilized, low carbon steel has a low melting point temperature. the matrix materials were as-atomized al powders (99.8% purity) including an mean particle size of 18.3 m (cdh company, india), steel 316l powder samples with a mean particle size of 45 m (cangsha easchem co, china) were used as toughness reinforcements, and nickel powder samples with a mean particle size of 9.922 m (metco company, germany) were used as reinforcements. expectantly improve the mechanical characteristic at dynamic load [14]. a hybrid fgm (ai-ni-steel 316l) with varying volume and amount has been created. powder metallurgy was used to create three different types of layered al-ni-steel functionally graded materials in this study. five layers consist of the fgms samples., all the initial layer 2mm thickness is created by (%75. ni,%25. al) and all the fifth layer has a thickness of 2 mm. (%33.3 ni, %33.3al, %33.3 316l steel). each layer's ingredients are combined according to pre-determined weight ratios. for all concentrations, the mass of ni, al, and 316l steel is shown in table 1, that have been used in this study. the weight of the compounds is calculated by using specific density of the powder. milling could be done in strong shaker crushers, in which small quantities of about 10 to20 g have been milled at quite a period, mostly by alloy inspection, or in lesser planetary milling, in which large amounts of particles (approximately 200 g) could be shredded, or in attritors, where even larger quantities can be milled at once. shaker crushers operate within about 1200 rev / min, radial mills at 150 to 600 rev/min, and powder at 100 nomenclature xrd x-ray direction greek symbols fesem scanning electron microscopy k scherrer constant xrf x-ray fluorescence 2ɵ the angle between transmitted beam and reflected beam. fwhm full width at half maximum λ the x-ray wavelength b the line boarding at fwhm in radian. subscripts d is the crystallite size hkl the assignment of the miller indices 204 ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 to 200 rpm. each layer's ingredients are blended according to predetermined weight ratios. mti ball mall was used to k eep the mixing duration consistent for all samples (30 minutes) [108]. 10 mm in length and diameter were used to create functionally graded material samples. table 1. illustrates the weight composition distribution of the first alni-316l steel sample1 for fgm. layer number %ni %al %steel thickness layer(mm) compound weight(gm) 1 75 25 0 2 1.145 2 50 25 25 2 1.4 3 25 25 50 2 0.749 4 12.5 50 12.5 2 0.677 5 33.33 33.33 33.33 2 0.99 the samples were pressed with an 800 mpa force with a spanish-made press equipment fig 4 after weighing and mixing the powder. delaminated (cracking across the particle) specimens were failing in the testing methods at very high pressing pressure; this is mostly because of the work-hardening effect. however, extremely low pressure was unable to produce a strong enough compact. detailed characterization and analyze the elemental composition of the fgms compound powder was carried out using x-ray fluorescence xrf. the mixed powders were filled and uniaxially cold pressed in a steel die as shown in fig 2. pressures of compaction ranged from 50 to 800 mpa [109]. compaction pressures ranged are used to abstain dynamic load characteristic in this research. aluminum compaction behavior was quantified by taking into account the densification of metal particles during uniaxial compaction. the influence on samples along with their morphology was considered when evaluating compressibility behavior. the ability can analyze the effect of particle geometries and matrices stiffness on the compression test is allowed by a development of compaction values along pressing pressure. the greens preform are weighed with 0.001 g accuracy. a micrometer caliper was used to measure the dimensions (0.01 mm). then, utilizing the vacuum furnace and an argon environment, all of the green produced fgms compacts samples were sintered at 600 °c. three argon gas flow rates 6, 7, and 8 m/s were selected. the spaceman was sintered by warming, then to 400°c at a rate of 10°c/min for one hour, then to 620° c for three hours. the heating rate was less than 10 °c/min throughout the process. the heating rate was less than 10 °c/min throughout the process figure to the heating rate was less than 10 °c/min throughout the process to avoid the melting point temperature of al and keep the original shape. sintering is a process that increases the strength of compressed beams. an argon gas environment furnace was used for the sintering process. fig 3 depicts the temperature change in the furnace like a time dependent during the sintering temperature. all zinc stearate in the sample evaporates almost completely at 335°c, and the structure is completely destroyed after sintering. during sintering, argon gas is provided at a steady flow rate of 50 ml/min to prevent aluminum from oxidizing fig. 3. fig. 4 depicts the final shape of the beam samples figure 2. a steel dies. . figure 3. during the sintering process, the temperature of the furnace changes over time figure 4. final shape of the beam samples ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 205 3. results and discussions other than ni, steel, and al, the xrf gives confirmation of elements. the xrf data also serve in validating the purity and quantity of the initial elemental powders, as well as preventing contamination of the powders during mixing and sintering sample manufacturing. detailed characterization and analyze the elemental composition of the fgms compound powder was carried out using x-ray fluorescence xrf table 2. table 2. chemical compositions percentage wt. of sample 1 by using xrf test. layer number wt% ni wt% al wt% fe wt% mo wt %c wt% cr 1 37.762 33.13 19..31 4.125 0.02 5.77 2 53.125 25.10 17.433 0.562 0.03 4.73 3 25.75 25.21 40.11 1.111 0.04 8.75 4 25.75 25.11 40.11 0.251 0.04 2.11 5 37.762 33.13 19..31 4.125 0.02 5.77 the mechanical behavior of aluminum-nickel-316steel alloy was tested experimentally according to astm e-8m standard. samples were created as shown in fig. 5 the toughness is measured using concepts of linear fracture mechanics (lefm), as well as the structural hardness characteristics, according with astm e.8 standards testing protocol. work piece tension samples with a diameter of 12.6 mm as well as a length of 3 cm in accordance with astm e.8m. figure 5. tensile test specimen dimensions the elastic modulus and as well as the maximum tensile strength of every fgm beam layer of the three samples were calculated in this manner being shown in figures 5.4.and figures 5.5 elastic modulus may be seen in the graphs. figure 6. values of maximum tensile strength for various al,st,ni ratios in 3d wall figure 7. values of maximum tensile strength for various al,st,ni ratios in 2d wall figure 8. yield stress comparison 206 ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 figure 9. stress at peak comparison figure 10. elasticity modulus values for various alloy ratios (al, ni, steel) fig. 7 demonstrate the results of tensile tests on stepwise al/ni/st fgm compact specimens and each layer sample. the yield stress of an al/ni/steel fgm compact specimen is shown in figure.8 in comparison to each sample. the maximum yield stress value was found in the sample1. the yield stress and module elasticity values of al/ni/st fgm compact specimens are higher than those of steel (350mpa), and this is considered a significant improvement in mechanical qualities over those of steel (100 percent steel). the ultimate stress value of al/ni/st fgm exceeds the ultimate stress value of stainless-steel grade 440c(760mpa). the young's modulus of fgm samples is shown in fig.10. nickel had a young's modulus of (211 gpa), while aluminum had a value of (73 gpa), and steel had a value of (200 gpa). the three samples for the percentages of nickelaluminum-316 steel compact are in the range of these three values. from a thermodynamic standpoint, carbon could've been dispersed at temperatures over 730°c, but in practice, temperatures of >900°c are necessary to enable rapid and thorough dissolution. due to the slower diffusion of metals alloy elements, even increased temperature are necessary, and involve various ni doesn't really fully homogenize even at the greatest temperature, because of fe’s extremely slow solid phase diffusion. steel 316l was chosen for this study because it has a low carbon content and hence avoids excessive sintering temperatures. because the al and sus3 16l particles reacted together during the sps process, intermetallic compounds such as cr.ni.fe.fe and alfe3 were produced in the al-sus316l composite, according to the x-ray diraction (xrd) patterns. xrd and scanning electron microscopy (sem) were also us ed to demonstrate the presence of these intermetallic complexes .2 deg/min for scanning. the xrd test results of layer1-sample1 are shown in the fig. 11 and table 3. figure .11 xrd of layer1-sample1-layer1 table 3 xrd data of layer 2-sample 1 hkl dhkl(n.m) peak position (2θ °) fwhm β(°) al{111,38.50789} 59.16903096 38.50789 0.14854 ni{111,43.63404 } 40.56789866 43.63404 0.22031 cr.fe.ni{100,44.55621 } 37.84052244 44.55621 0.23696 ni.fe{200,50.80935 } 34.03970650 50.80935 0.26985 ni{200,51.89963 } 31.86370773 51.89963 0.2896 al{220,65.15075 } 44.89085534 65.15076 0.21934 fe.ni.cr{220,74.73005 } 30.85218341 74.73005 0.33838 ni{220,76.45084 } 28.52529078 76.45084 0.37027 al{311,78.29929 } 35.8318282 78.29929 0.2986 fe{211,82.49713 } 31.67851215 82.49713 0.34837 ni{311,92.69211 } 27.44187834 90.69211 0.43021 ni{311,93.04405 } 23.02792293 93.04405 0.52366 ni{222,98.56661 } 21.25812063 98.56661 0.59835 all of the data is calculated with the use of a panalytical x, pert program and jcpds (publishing and sharing powder diffraction data for material identification) or icdd cards for xrd analysis. equation (4 -1) is used to calculate d(h,k,l) spacing, as indicated in table 4. (3,4,5,6,7). fwhm is used in xrd for calculating crystallite size by using scherrrer equation. fig. 12 depicts the morphologies of pure al, ni, and sus316l powders. pure aluminium powder has an uneven and rough surface with varying particle size distributions (fig .12a). the sus316l powder (fig .12b) and pure nickel powder (fig .12c) both displayed irregular morphologies; however, the nickel powder particles had rougher surfaces than the pure al ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 207 and steel316l particles. similar to the pure al,ni, and sus316l powders, the al-ni-sus316l composite powder of sample 1 -layered 2 (fig. 12d) displayed a wide size distribution of irregular and rough -surfaced particles. the composite powder particles, on the other hand, had smoother surfaces than the sus316l, ni powder since the former had been crushed and blended before usage and subjected to mechanical forces during the ball milling process. figure 12. sem micrographs and eds spectra of (a) pure al, (b) sus316l, (c) pure ni, and (d) al – steel 316l and ni composite powder sample 1-lyered 2 the phases of the four powders, their sintered bulks, and the composite examined with xrd diffraction patterns are shown in figure 4.12. for comparison with the composite, pure al, ni, and sus316l bulk were produced under the same fgms process parameters. fig.13 shows the peaks for al and -fe alone in the al, ni,steel s316l, and al-ni-steel 316l composite powders. this means that during the ball milling process, the al and steel 316l powders did not react with each other. as illustrated in fig.14, intermetallic compounds such as cr.ni. fe111, cr.ni. fe200, al.ni311), cr.ni.fe222, and al.fe.mn.mo were discovered. the sintering technique was thought to have created these intermetallic compounds by reacting al, ni, and the components of sus316l. it's further corroborated by the fact that the peaks of these intermetallic compounds were absent from the al-steel 316l-ni composite's direction pattern. the contaminants and oxide coatings of the particle surfaces created during the sintering process [21,22] were removed by cleaning . because of the high temperature of the sintering, the particles locally react with one another, potentially resulting in the creation of intermetallic compounds [23]. the sintering procedure was carried out at 630 c in this work, which is lower than the melting temperature of al .in the semisolid state. the liquid phase did not exist indefinitely; it appeared in little amounts and then vanished. due to the existence of micro-plasma, it appears that the temperature within the mold was over 630 c throughout the sintering process. the temperatures inside the mold and at the mold's surface may differ slightly [24]. as a result, we discovered that we couldn't process the materials above 630 degrees celsius due to the formation of liquid phases. figure.13 pure al, steel316l, ni, and al-ni-steel powder xrd patterns figure.14 xrd of layer2sample1 208 ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 fig.15 shows sem micrographs and eds of pure al bulk, steel316l bulk, ni bulk, and al -steel316l-ni composite. because the sintering temperature was so close to the melting point of al, this happened. fig.15a, on the other hand, shows some grooved-holes that appear to be pores. these grooved-holes are thought to have been made by over -etching used to examine the microstructure of pure al bulk. because the sintering temperature is substantially lower than the melting point of steel s316l, the steel 316l bulk seems to have many pores and a much lower density, as shown in fig.15b. because ductile al has a larger relative density table 4., the composite has a higher density. furthermore, due to the repositioning of the particles in the semisolid state during the sintering process, densification happens quickly once the liquid phase is produced [25]. as a result, liquid phase could seep into the pores of the composite, causing it to fail. table 4 the physical relative density properties of al, ni, steel and al-ni-steel composites sample relative density % pure al 98.4 pure ni 80.9 pure steel 316 79.9 al-ni-steel316 95.8 because the heating rate is substantially lower than the values melting point of steel316l, the steel bulk and nickel seems to have numerous pores and a significantly lower density in other hands, as shown in fig.16 and table 4. surprisingly, as shown in fig.16 c, the al-steel316l-ni (sample 1layered 2) composite has a high density of almost 95 percent. the liquid al (25 percent) appears to penetrate the al vol. percent steel 316l composite's pores and effectively seal them shut. in other words, the higher density of ductile al is responsible for the higher density of the composite. additionally, due to the repositioning of the particles in the semisolid state throughout sintering process, the densification happens quickly after the liquid phase is produced [25]. figure 16. (a) pure al bulk, (b) a steel 316l bulk, (c) pure ni bulk and(d) composite made of 25% aluminum, 25% steel, and 25% nickel are shown in sem micrographs and eds analysis, respectively the xrd patterns, sem, and eds all supported the existence of these intermetallic complexes. the al-steel316l-ni composite's mechanical hardness may be raised as a result of the formation of these high -hardness intermetallic compounds between the al and steel316l matrix. similar to this, intermetallic compounds are thought to establish a strong chemical link between the al, ni, and steel 316l matrix, perhaps enhancing load transfer. additionally, the composite could become stronger as a result of the semisolid state sintering process. as was already indicated, the increased mechanical capabilities of the composite may be due to the densifying tendency seen during the semisolid state sintering process. because the steel316l, ni, al matrix and intermetallic compounds were mixed, it's possible to increase the bond s trength between the matrices. 4. conclusions with the aid of mechanical ball milling and semisolid state sintering, we have produced al-sus316l composites with success. vickers hardness for the composite made of (percentage 50 ni, percent 25 al, and per cent 25 steel316l) is about 190 hv. by combining ni ,al and sus316l, intermetallic compounds like cr.fe.ni and ni.fe were created. the alsus316l composite's xrd patterns, sem (eds), and eds mapping results all supported the presence of these intermetallic compounds. it's probable that the development of these intermetallic compounds with high mechanical hardness plays a significant role in the al-sus316l composite's strengthening mechanism. additionally, the strengthening effect of the composite may also b e influenced by the semisolid state sintering process and green pressing. to clearly identify the components impacting the mechanical strength of the composite, further thorough studies are required, such as tem, tensile strength analyses, and corrosion resistance tests. thus, the al-sus316l composite created by the cold pressing and sintering process might be used in the engineering industry as a lightweight, high-hardness multifunctional composite material. ali oudah et al. /al-qadisiyah journal for engineering sciences 15 (2022) 202–209 209 references [1] r. singh, v. bhavar, p. kattire, s. thakare, s. patil, and r. k. p. singh, “a review on functionally gradient materials (fgms) and their applications,” iop conference series: materials science and engineering, vol. 229, no. 1, sep. 2017, doi: 10.1088/1757 -899x/229/1/012021. 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[16] m. r. siti nur hazwani, l. x. lim, z. lockman, and h. zuhailawati, “fabrication of titanium-based alloys with bioactive surface oxide layer as biomedical implants: opportunity and challenges,” transactions of nonferrous meta ls society of china , vol. 32, no. 1, pp. 1–44, jan. 2022, doi: 10.1016/s1003-6326(21)65776-x. article al-qadisiyah journal for engineering sciences 15 (2022) 212–217 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ahmed.shakir@qu.edu.iq (ahmed al-saadi) https://doi.org/10.30772/qjes.v15i4.855 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. analysis of aerodynamics around tall buildings with several configurations ahmed ali shakir al-saadi department of mechanical engineering, college of engineering, university of al-qadisiyah, ad-diwaniyah, iraq. a r t i c l e i n f o article history: received 8 july 2022 received in revised form 14 august 2022 accepted 21 september 2022 keywords: aerodynamics wind tall buildings cfd drag coefficient a b s t r a c t the streamlined exterior shapes of tall buildings are important to reduce the effect of the wind. therefore, an examination of different techniques for the exterior design of tall buildings is required. this study aims to analyses some tall buildings to select the most streamlined design in order to reduce high wind risks. the benchmark used in the current study is a building with a height of 120 m and a triangular cross-section with a side length of 20 m. a square cross-section twisted building design is used as a modified model in tall buildings of about 120 m. the rotation angle of the building is 45° for each twisted path. six configurations of this type of building are tested with different radiuses of fillet on their edges, which are 0, 1, 2, 3, 4, and 5 m respectively. all geometries of the buildings are created by solidworks, while mesh and simulations are achieved using ansys fluent. a great agreement is obtained between the current results and the previous related study for the benchmark. using twisted buildings with a fillet of 5 m can lead to a reduction of the drag coefficient of about 27.5% relative to the benchmark. wind in a horizontal direction can be reduced by using twisted geometry. but in terms of separation, using a fillet with a large radius can lead to avoiding early separation of air. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction several criteria determine the design and location of tall buildings in cities. climate is the most important parameter for designing tall buildings [1-4]. residential areas' environments should be improved for more comfortable and optimized energy use. and that can lead to a controlled environmental situation in these specific areas. wind force is one of the most effective climatic factors in tall building designs [5]. a difference in temperature can lead to a change in the static pressure and that can lead to an increase in the velocity of wind [6]. most tall building designs are more interested in studying wind loads than earthquake loads [7-10]. architectural design, structural, and mechanical approaches are the main three approaches to designing tall buildings. the structural approach focuses on earthquake and wind loads for tall buildings because these types of buildings are more vulnerable to the external conditions than low-rise buildings [11]. it is necessary for evaluating wind loads in tall buildings and the uncommon exterior designs, especially in buildings with more than 40 stories, because of the changing wind loads fast and suddenly [12]. all architectural designers aspire to minimize the effects of wind on buildings in parallel to reduce the swirls behind the buildings, at corners, and near the ground. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i4.855 http://creativecommons.org/licenses/by/4.0/ ahmed al-saadi /al-qadisiyah journal for engineering sciences 15 (2021) 212–217 213 many studies have been conducted for the exterior design optimization of tall buildings. davenport [13] examined the effect of the exterior design of buildings on the overall behaviour of aerodynamics by using many model tests. baghaei [14] investigated aerodynamic optimization of high-rise buildings. in his study, he focused on climate-roofing in iran. 40 prototypes with different climates were used to achieve the optimal design. the optimal design of a building should have a minimum of eddies around the building. in the 1990's, high-rise buildings increased overall in the world, and that led to an increase in the studies of aerodynamics of tall buildings to reduce the effect of wind on this type of building [15-19]. some researchers examined tapered and set-back design techniques for high-rise buildings [20, 21]. other techniques of exterior building design, such as openings and spoilers, were used to reduce the effect of the wind on buildings [22, 23]. kelly et al. [24] studied the influence of helical or twisted building models on the aerodynamics around buildings to resist wind loads. tse et al. [25] analysed available space and cost regarding tall building designs and their effects on economic terms. tanaka et al. [26] investigated many cross-sectional models of tall buildings, such as square, rectangular, circular, elliptical, and angle-modified models, in addition to helical and compound models. some researchers mentioned that changing the exterior design of buildings has been restricted by many design factors, not just aerodynamics [27-29]. furthermore, different perspectives have been taken during the design of tall buildings, in addition to aerodynamics [30-37]. pressure coefficients for high-rise buildings have been studied to provide a clear picture of pressure differences [38-39]. while some studies concentrated on the impact of wind on pedestrians [40-43, 56]. some previous studies used autodesk flow design for simulating the aerodynamics around buildings [2, 44, 45]. some recent research has focused on the applications of cfd in tall buildings [54, 55]. the main aim of this study is to analyse the drag force on tall buildings. six different designs of tall buildings with a twist, in addition to the benchmark model, are used to achieve the optimal design for these proposed designs. the building with the minimum drag force is the best in terms of wind aerodynamics. that can lead to a decreased wind load on the building. studying the aerodynamics of tall buildings is limited in many countries, such as iraq, and that is the greatest motivation to carry out this numerical study. 2. numerical approach the analysis of aerodynamics around high-rise buildings in this research was achieved by using cfd simulation. solidworks and ansys fluent were used to create and simulate all configurations of tall buildings. all the 3-d full-scale configurations used in the current work were created using solidworks software because of the complex shape of the twist. ansys fluent was used to create a mesh around the main geometry and simulate all models inside the computational domain. 2.1. numerical models six twisted building models, in addition to the benchmark, were created. the benchmark had a triangular cross-sectional area with sharp edges, as in daemei et al.'s study [2]. nomenclature 2-d two-dimensional l height of the building 3-d three-dimensional r fillet radius cfd computational fluid dynamics v velocity a frontal area of the building cd drag coefficient greek symbols fd drag force ρ density figure 1. the benchmark (a) and twisted without fillet model (b). 214 ahmed al-saadi /al-qadisiyah journal for engineering sciences 15 (2022) 212–217 while twisted building models have the same conditions except for the radius of fillet, which was nil, 1, 2, 3, 4, and 5 m respectively. all these buildings have the same height, which was 120 m, and the ratio of height to width was 6. figure 1 shows the benchmark (a) and twisted without fillet model (b). the overall width of the benchmark model was 20 m, exactly the same as the aspect ratio (l/w=6). it was noted that the width of the cross-sectional area of the twisted model was 20 m. but the overall width of the twisted model was more than 20 m because of the twisted angle. figure 2 illustrates all twisted models in isometric and top views. the first model on the left side is without a fillet. then the rest, with a radius of 1 m to 5 m, respectively. it was noted that the frontal area of these twisted models was not equal because of the magnitude of the fillet radius. the frontal area of all building models was calculated by using solidworks software to achieve more accurate results. 2.2. computational domain set-up ansys fluent software was used to create a computational domain around the 3-d geometry of the building. different dimensions for the computational domain have been used depending on the scale of the model and conditions [46-48]. figure 3 shows the benckmark model inside the computational domain. recommended dimensions by bairagi and dalui [48] were used in the current study. the distance from the inlet to the tested model was five times the building's height. while the distance from the tested model to the outlet was 15 times the building's height, the overall width of the computational domain was 10 times the building's height, in addition to the width of the building. the overall height of the computational domain was 6 times the building's height. 2.3. mesh refinement creating mesh is a very important step to obtaining accurate results. therefore, mesh refinement, especially near the wall of testing geometry, is crucial. tetrahedral mesh is used in all cases of the present study because of its sharp edges and twisted geometry. prismatic cells are added around buildings and over the ground to improve the quality of the mesh. seven layers of prismatic cells are used as the optimal case in the current study. a growth rate of 1.2 is used in the global domain of mesh. figure 4 shows the side view of the mesh throughout the computational domain. real air movement is not completely horizontal, but it can be in any direction because of the topography of the earth. some previous studies focused on the direction of air and the effect of it on pedestrian comfort, as shown in figure 5 [49-53]. the wind speed increases as the distance from the ground increases. the highest velocity of air could occur at a height of about 500 m [14]. in the current study, the direction of air is completely figure 2. all twisted building models. figure 3. tall building inside the computational domain figure 4. mesh with seven layers of prismatic cells ahmed al-saadi /al-qadisiyah journal for engineering sciences 15 (2021) 212–217 215 parallel to the horizontal ground of the computational domain. 2.4. drag coefficient the drag coefficient (cd) is a dimensionless quantity which represents, in the current study, the resistance of a building against the wind. it is better to decrease this amount as much as possible to increase comfort standards for pedestrians and to decrease serious problems for pedestrians at the same time. each shape has a different drag coefficient than the others. this dimensionless quantity can be mathematically clarified by the following equation (1) [2]: 𝐶𝐷 = 2 𝐹𝐷 𝜌 𝐴 𝑉 2 (1) where cd represents the drag coefficient, and it is a dimensionless quantity. fd represents the drag force (n). ρ represents the air density (kg/m 3) at 15℃. a represents the frontal area of the building (m2). v represents wind speed (m/s). 3. results and discussions the numerical simulations were achieved in two stages. first, cd was evaluated for the building with a triangular cross-sectional area as in daemei et al.'s [2] study to validate the methodology of the present study. then, six modified exterior shapes of twisted buildings were simulated. 3.1. validation of numerical results the mesh dependency test is the major step to achieving accurate numerical results. therefore, a variety of mesh densities were tested to obtain the optimal number of meshes for this study. figure 6 shows the mesh dependency test for the benchmark in the present study. validation of the numerical simulation results for the benchmark in the current study was accomplished by comparing them with the previous study of daemei et al. [2] for similar conditions. the benchmark model of the building in the present study had an equilateral triangular cross-sectional area. the length of the side of the triangle was 20 m, while the overall height of this building was 120 m. this baseline model had sharp edges on all sides, exactly similar to the model in the previous study [2]. figure 7 shows the drag coefficient with the time for the benchmark in daemei et al. study [2]. they used autodesk flow design to achieve all drag coefficients for many configurations. figure 8 shows the cd as a function to iterations for the benchmark in the present study; ansys fluent was applied to obtain all numerical results. table 1 shows the cd in the current study and previous study. a good agreement on the benchmark data between the previous and present studies was achieved. table 1. drag coefficients for the benchmark. a previous study [2] current study software autodesk flow design ansys fluent cd 0.79 0.8 percentage error (%) ----1.2 figure 7. cd of the basic model in daemei et al. study [2] 0 0.2 0.4 0.6 0.8 1 1.2 0.e+00 1.e+06 2.e+06 3.e+06 4.e+06 5.e+06 cd number of mesh figure 5. airflow around buildings [14] figure 6. cd as a function of mesh dependency. cd time (s) cd number of mesh 216 ahmed al-saadi /al-qadisiyah journal for engineering sciences 15 (2022) 212–217 3.2. numerical simulation results of modified buildings the numerical simulations for the modified models of buildings were conducted. the cd was assessed on twisted models of buildings. six modified models were simulated. all modified models had the same overall height, cross-sectional shape, and twisted angle. the first model had sharp edges, while the other five had fillet radiuses of 1, 2, 3, 4, and 5 m. the frontal area of these models was not equal because of the different edges. and it was calculated by using solidworks for more accurate results. all values of cd were recorded and evaluated when the airflow was in a stabilization mode. six modified models, in addition to the benchmark, were investigated. a comparison between all models was employed to figure out which model has the lowest drag coefficient in order to reduce drag force and bending torque. it is clear from figure 9 and table 2 that the cd of the benchmark was about 0.8. while the cd for all modified buildings was less than 0.7, as shown in figure 9. the twisted building without a rounded fillet had the highest cd of the modified group of buildings because of early separation of air. using fillet on all edges can reduce cd as well as vortex formations behind the building. according to figure 9 and table 2, increasing the radius of the fillet decreases the drag coefficient. increasing the radius of fillet for edges can lead to decreasing cd, but that can be affected by the capacity of the building. therefore, a balance between cd and the capacity of the building should be taken into consideration. twisted tall buildings, on the other hand, are an expensive style to implement, but they are important in earthquake zones, as mentioned in previous studies [2, 24]. table 2. drag coefficients for all models 4. conclusion six modified exterior shapes of buildings, in addition to the benchmark, were numerically simulated using ansys fluent to determine the optimal design among them, in proportion to the drag coefficient. according to the numerical simulations of the present work, twisted buildings with a square cross-sectional area and using a radius of fillet of 5 m had the best performance in reducing cd. because this technique can result in less swirling wind at the edges. the twist in the building helps the wind flow in an inclined direction. therefore, the horizontal velocity of air can be decreased to create more comfortable conditions around tall buildings. all results of numerical simulations for modified models were compared to the benchmark and between them as well, in order to define the best exterior shape of a tall building. it is clear that the sixth modification had the lowest cd, which was 0.58. and that means the cd was reduced by 27%. references [1] mooneghi, m.a. and kargarmoakhar, r., 2016. aerodynamic mitigation and shape optimization of buildings. journal of building engineering, 6, pp.225-235. 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[56] wu, y., zhan, q. and quan, s.j., 2021. improving local pedestrian-level wind environment based on probabilistic assessment using gaussian process regression. building and environment, 205, p.108172. article al-qadisiyah journal for engineering sciences 13 (2020) 153–157 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. tel.: +964(0)7734177899 e-mail address: salih.rushdi@qu.edu.iq (salih a. rushdi) https://doi.org/10.30772/qjes.v13i2.663 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. investigation of overall mass transfer coefficient of co2 absorption in packed column zahraa n. abd a, salih a. rushdi a* a chemical engineering department -faculty of engineering – university of al-qadisiyah-iraq a r t i c l e i n f o article history: received 22 april 2020 received in revised form 20 june 2020 accepted 25 june 2020 keywords: co2 absorption monoethanolamine (mea) diethanolamine (dea) triethanolamine (tea) overall mass transfer coefficient (kga) packed bed reactor (pbr) gas chromatography(gc) a b s t r a c t mixtures of different types of amine solution monoethanolamine, diethanolamine, and triethanolamine were experimentally used to investigate the overall mass transfer coefficient (kga) at different operating parameters. the experiments were made in a packed bed reactor (pbr) with 75 cm in high and10 cm inside diameter as a gas-liquid contactor at 25℃ and atmospheric pressure, using a simulation gaseous mixture (air, carbon dioxide) with recycle stream (semi-continuous process). experimental design process taguchi was employed. four factors and three levels were chosen and exploded using l9 (3 ^4) orthogonal array design. these parameters for semi-continuous process were namely: gas flow rate 5,10,and 15 l/min ,airflow rate80,90,and 100 l/h, liquid flow rate 400,450,and 500 ml/min and time absorption time 30,45,and 60min . a shimadzu gc-8a gas chromatograph with a thermal conductivity detector was used to measure the co2 concentration absorbed in aqueous blended solution. the maximum value for co2 loading was 8.622 (mol co2/mol amine) at 15 l/min gas flow and 450 ml/min liquid flow and 100 l/h airflow for 60 min from absorption time. the results showed that the max value of kga is 0.048 s -1. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction elevation in the emissions regarding atmosphere’s anthropogenic co2 is considered to be challenging due to the fact that it is mainly contributing to the global warming. fossil fueled plants are the main emission source, particularly plants using coal as the main fuel [1]. co2 is one of the gasses that are naturally-occurring, also it has main impact in reflection related to the solar radiation back to earth, and that will keep the surface temperature of the planet at suitable levels for the life [2]. throughout the past tens of years, there has been an increase in the emissions related to other greenhouse gases (ghgs), in addition to co2, such as ch4, n2o, hfc, perfluorocarbons as well assf6 [2]. worldwide, co2 which is emitted from the power plants is considered to be about 40% of the overall emissions of co2 and within the ongoing businesses and industries, it is anticipated to be elevating to about 60% prior to the end of this century [3, 4]. for the http://qu.edu.iq/ mailto:salih.rushdi@qu.edu.iq https://doi.org/10.30772/qjes.v13i 154 zahraa n. abd , salih a. rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 153–157 purpose of preventing excessive co2release in atmosphere, carbon capture and storage (css) is of high importance in the industry of fossil fuel. such an approach includes co2 capturing, compress it to transport, and after that store it permanently (in gas fields and depleted oil). the major application regarding css is in the industrial point sources as fossil-fuel power plants, production of fossil fuel, facilities for hydrogen production, industrial plants (steel and iron blast furnaces, chemical processes, and cement kilns) [5]. the absorption is the most important approach to remove co2 from the industrial waste gases as well as for synthesizing and for purification of natural gas. such a process passes flue gas via liquid which have the ability to absorb co2 (in absorber vessel) and after that releasing co2 at increased temperatures in regenerator vessel (stripper) [6, 7]. aqueous alkanolamines are the major chemical solvent for capturing acid gaseous. alkanolamines have been generally applied as absorbents for the capturing of co2, alkanolamine’s structures involve primary, secondary, ternary amines including no less than single (oh) as well as amine group. in the case of chemical solvents, primary amines such as mea, secondary amines dea, amino-ethoxyethanol (dga), and diisopropanolamine (dpa), tertiary amines such as tea and mdea, as well as alternatives to amines such as hot potassium carbonate, are used. such alkanolamines were applied as chemical absorbents for removing acidic gases like (h2s, co2). a lot of the works on the chemical absorption with the tertiary alkanolamines like dea, tea, in addition to their associated apply of mixed amine absorbents, particularly blends the primary and tertiary amines (like tea and mea) or the secondary, as well as tertiary amines (like tea and dea), has increased or them together [8]. the amine blending process has many benefits, the most notable of which is: • dynamic efficiency improvement. • reducing problems related to the decomposition and operation of solvents resulting from corrosion. • flexibility in the range of amines available to tailor and optimize the composition of the solvent to achieve the highest absorption efficiency. • maintain a high absorption rate in single amino solvents in a mixture of individual ingredients. • reduced energy requirements for solvent regeneration [9]. the main benefits related to the technology of chemical absorption are as follows: 1. chemical absorption can be considered as a major developed approach to capture co2, operating at normal pressure and temperature. 2. for tens of years, it was commercialized, though not for the capture of co2 from power plants. 3. it can be used efficiently to dilute co2 system (general flue gas from power plants) [10]. also, there are certain disadvantages related to this approach, as follows: 1. amine oxidative degradation through so2, no2, and o2 in flue gases that induce a high absorbent makeup rate. 2. the energy consumption is high throughout high temperature absorbent regeneration. 3. the equipment corrosion rate is high. 4. the equipment size is large. it was initiated primarily for: 1. investigating the capacity of (dea) as a blend for mea and tea solution in co2 scrubbing via a semi-continuous process. 2. evaluating the effect of various parameters on the process using taguchi analysis. 2. material and methods mea, dea, and tea were used as solvents. a co2 cylinder (pure 99.99 percent) was used as the inlet gas source. during every cycle of the experiment distilled water has been used. table 1. shows the chemical material used in this work. table 1. chemical material (amine) use in academic work 2.1. mass transfer for gas absorption mass transfer can be considered as one of the common phenomena which happen in simple, daily life in addition to the engineering process. in the case of absorption, the absorption of the gas in the liquid happens in the case of the transfer of the gaseous components from gasto liquid-phase. in the process of the chemical absorption, the gaseous component undergoes the absorption by liquid phase through combining the reaction and the diffusion mechanism. the processes of the chemical absorption are like systems that are aqueous amine-based, systems that are based on the ionic liquids, and ammonia manufacturing systems. as an explanation, the entire process rate can be viewed a layer of gas–liquid contact. the mass transfer must be enhanced with the increase of the turbulence in each of the liquid as well as the gas phases. the mass transfer happens through combining the diffusional and the mechanism of the chemical reaction in the boundary layer so the entire rate may be represented with each of the mass transfer and the chemical reaction. numerous hypotheses may define the process of the gas absorption, like the penetration theory, film theory, boundary layer theory, and the surface renewal theory. the film model which is simpler mathematically, compared to the models of penetration is usually utilized, based on the film theory, a stagnant film of thickness δl is supposed to be existing at gas and liquid interface as has been illustrated in fig. 1.the mass transfer through the molecular penetration takes place via a thin liquid gas layer which is δ thick, and there isn’t any concentration gradient in liquid bulk. in the theory of the film, the coefficient of the mass transfer kl and kg are proportionate to the coefficient of the diffusion dco2-amine and inversely proportionate to the thickness of the film. kl stands for the mass transfer coefficient for the liquid side and is equal to: [11] nomenclature co2 carbon dioxide greek symbols kga overall mass transfer coefficient  co2 loading kg gas film physical mass transfer coefficient δ film thickness kl liquid mass transfer coefficient n (co2,abs) number of moles of co2 absorption pbr packed bed reactor density g/cm3 molecular weight [g/mol] chemical formula abbreviation chemical name 1.0117 61.084 c2h7no mea monoethanolamine 1.097 105.137 c4h11no2 dea diethanolamine 1.124 149.190 c6h15no3 tea tiethanolamine zahraa n. abd , salih a. rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 153–157 155 𝜹𝑳 = 𝑫𝑪𝑶𝟐 −𝒂𝒎𝒊𝒏𝒆 𝒌 𝑳 (1) similarly, the equation below may be resulted for the coefficient of the mass transfer in the gas phase: 𝜹𝑮 = 𝑫𝑪𝑶𝟐−𝒂𝒎𝒊𝒏𝒆 𝒌𝒈 (2) figure 1. carbon dioxide mass transfer into the liquid phase with a chemical reaction based on the film theory [11] 2.2. determining the overall mass transfer coefficient (kga) kga is an important part of this research. mass transfer occurs when a component. in the scrubber, a simulated mix of gas which contains a (co2) and b (air) which flow toa packed column from bottom continuously contacts with the solution of the amine which flows from the top in a column. at the same time, all current touches the opposite current column. in the present study, has been a reasonable theory. taking under consideration ideal gas regulations for inlet and outlet gases at different temperatures values, f1/f2 may be substituted by (p1 /p2) (t2 / t1)(y1 / y2). which is why, the coefficients of the general volumetric mass transfer becomes : 𝑲𝑮𝒂 (𝒔 −𝟏) = 𝑸𝒈 ( 𝑳 𝒔 ) 𝑽𝑳 (𝑳) 𝒍𝒏 𝑭𝟏( 𝒎𝒐𝒍 𝒔 ) 𝑭𝟐( 𝒎𝒐𝒍 𝒔 ) (3) where: qg=gas flow rate, (l/s) f1= co2 molar flux at inlet, [mol/s] f2= co2 molar flux at outlet, [mol/s] vl = is the absorber volume of the liquid. 2.3. taguchi method of analysis a packed bed reactor was used to study the capture. mixed amine concentration was 5v/v% mea+10 v/v% dea +5v/v% tea. we used the taguchi approach as an experimental design to reduce the multitude of experiments [12],[13]. this study utilized three levels for the variables. when using the taguchi method, it is important to determine the minimum number of experiments based on the following equation: n = 1+∑ (𝐿𝑖 − 1)𝑁𝑉𝑖=1 (4) the main factors affecting the rate of absorption in the essential series are (time of absorption) > (gas flow rate) > (air flow rate) > (liquid flow rate), meaning the time of absorption has the most important influence on the absorption rate followed by the rate of gas flow. table 2. shows the response of the removal efficiency factors to the s / n ratio, a maximum values from kga, when gas flow was 15 l/min, and airflow 100 l/h and liquid flow 500 ml/min. table 2. s/n ratio for removal efficiency level gas(co2) flow l/min air flow l/h liquid flow ml/min time min 1 -2.865 -2.870 -2.868 -2.812 2 -2.868 -2.868 -2.868 -2.880 3 -2.871 -2.867 -2.867 -2.912 delta 0.006 0.003 0.001 0.100 rank 2 3 4 1 3. experimental set-up a plexiglas column 0.75 cm of height and internal diameter of10cm [14] taken as scrubbing column as shown in fig.2 figure 2. experimental set-up for co2 capture using aqueous solution a metal frame is provided to the base. the gas inlet is located at the bottom of the column through which the gas travels to the top of the stream. we used a perforated spray at the gas inlet to help distribute gas in the column, by positioning the liquid inlet at the top of the column. where aluminum balls with a length of 10 mm and a diameter of 10 mm are used as random packing within the column, one of the most important advantages of packing is to enhance the surface area to transfer the mass and increase the contact time between gas and liquid. a drain valve is positioned at the bottom of the column to clear the column after the procedure and is inherently corrosive to collect the sample stream monethanolamine (mea), hence the use of a pvc container for feeding all tubes and fittings used are made of polyvinyl amine. the amino (mea, dea, tea) solution was pumped from the top of the column. a side current is arranged from the 156 zahraa n. abd , salih a. rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 153–157 pump to minimize the load on it, using the gas cylinder as the source of co2 the recycling stream is arranged at the bottom of the column leading to the feeding tank. for gas, the rotameter scale was 1–25 lmin−1, for liquid 100– 500 mlmin−1 and 10–100 lh−1 for air. co2 samples were obtained in the flask pipe. during each operation, the setup was cleaned with water to eliminate any pollutants and carbamates that were created during the column reaction. 4. results and discussion the experiments for mass transfer in a packed bed were studied based on co2 absorption into blended solutions from mea-dea-tea. sample taken after absorption experiments were analyzed for co2and amine content. in order to determine the co2loading in terms of (moles of co2/ moles of amine). gas chromatography (gc) was used to analyze the concentration of co2. the overall mole of co2 absorbed in the absorbent can be calculated by subtracting mol of co2 inlet from the outlet and the co2 loading can be calculated through 𝒏𝒄𝒐𝟐,𝒂𝒃𝒔 = 𝒏𝑪𝑶𝟐 ,𝑰𝑵 − 𝒏𝑪𝑶𝟐,𝒐𝒖𝒕 (5) 𝜶 = 𝒎𝒐𝒍 𝒐𝒇 𝑪𝑶𝟐 𝒎𝒐𝒍 𝒐𝒇 𝒂𝒎𝒊𝒏𝒆 (6) figure 3. maximum 𝑪𝑶𝟐 absorption capacity vs. absorption time for g(a, e, i) figure 4 maximum 𝑪𝑶𝟐 absorption capacity vs. absorption time for g(b,f,g) figure 5. maximum 𝑪𝑶𝟐 absorption capacity vs. absorption time for g(c,d,h) when comparison of the results obtained for 𝐶𝑂2 loading capacity vs. reaction time for the tested aqueous amine solution for groups (a,e,i), (b,f,g) and( (c,d,h) as shown in figs. 3, 4 and 5 respectively. we found that increase in the 𝐶𝑂2 loading of an absorbent with increasing time and mean that the solubility of carbon dioxide is increased under various parameters condition. 4.1. effect of 𝑪𝑶𝟐 loading on overall mass transfer coefficient 𝑲𝑮𝒂 the following figures show the main effect of 𝐶𝑂2loading on overall mass transfer coefficient kga in each group. according to equation (3) calculate the overall mass transfer coefficient kga s -1 (for semi-continuous process). in figs 7, 8, and 9 it is obvious that increasing the co2 load in amine solutions contributes to a reduction of the current active amine concentration, which subsequently decreases the overall mass transfer coefficient. this effect is mainly attributed to the co2 load in the amine solution is high. where (mea+dea+tea) blended amine solution are used in all three figures, mass transfer driving force from gas to liquid phase will be reduced. this effect is consistent with the work of each of the researchers. figure 6 progression of 𝑲𝑮𝒂 in a function of 𝑪𝑶𝟐 loading for semicontinuous processes (5% mea+ 10%dea+5%tea) g(a,e,i) 0 2 4 6 8 10 0 20 40 60 80 g(a) g(e) g(i) c o 2 l o a d in g (m o l c o 2 /m o l a m in e ) absorptiontime/min 0 1 2 3 4 5 0 10 20 30 40 g(b) g(f) g(g) absorption time/minc o 2 l o a d in g (m o l c o 2 /m o l a m in e ) 0 1 2 3 4 5 6 7 0 20 40 60 g(c) g(d) g(h) c o 2 l o a d in g (m o l c o 2 /m o l a m in e ) absorption time /min 0 0.01 0.02 0.03 0.04 0.05 0.06 0 5 10 g(a) g(e) g(i) "o v e ra ll m a ss t ra n sf e rc o e ff ic ie n t k g a ( s1 )" co2 loading(mol co2/mol amine) zahraa n. abd , salih a. rushdi /al-qadisiyah journal for engineering sciences 13 (2020) 153–157 157 figure 7. progression of 𝑲𝑮𝒂 in a function of 𝑪𝑶𝟐 loading for semicontinuous processes (5% mea+ 10%dea+5%tea) g(b,f,g) figure 8. progression of 𝑲𝑮𝒂 in a function of 𝑪𝑶𝟐 loading for semicontinuous processes (5% mea+ 10%dea+5%tea) g(c,d,h) the maximum value obtained from these experiments was 0.048 𝑆−1 in group g,h,i at gas flow 15 l/min and liquid flow rate 400,450,500 ml/min and air flow rate 80,90,100 l/h. while chen et al.,2015, they were found that 𝐾𝐺𝑎 was 0.0342 𝑆 −1 when absorption co2 using mea solution. chen et al.,2018, absorption of co2 using aqueous ammonia solution 𝐾𝐺𝑎 was 0.051 𝑆 −1. 5. conclusion a packed bed scrubber under semi-continuous operation was successfully used for screening blended amines with the aid of the gas chromatography (gc). the overall mass transfer coefficient ( kga ) of carbon dioxide absorption into blended mea-dea-tea solutions was experimentally measured using a laboratory-scale packed bed. the parameter used in this study were gas flow, liquid flow, air flow and absorption time. this study showed that the increasing by the gas flow rate, the liquid flow rate, the kga . this study showed that the increasing by the gas flow rate, the liquid flow rate, the kga values increased. also, increasing the co2 loading of amines lead to a kga decrease. references [1] s. f. hameed and s. a. 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[14] s. a. rushdi, developing correlation for prediction of gas holdup using genetic algorithm, al-qadisiya journal for engineering sciences, 2(2) (2009). 0 0.01 0.02 0.03 0.04 0.05 0.06 0 2 4 6 g(b) g(f) g(g) o v e ra ll m a ss t ra n sf e rc o e ff ic ie n t k g a ( s1 ) 0 0.01 0.02 0.03 0.04 0.05 0.06 0 2 4 6 8 g(c) g(d) g(h)o v e ra ll m a ss tr a n sf e r co e ff ic ie n t k g a mol co2/mol amine co2 loading article al-qadisiyah journal for engineering sciences 13 (2020) 306–313 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author: e-mail address: alameri.abbas@gmail.com (abbas fadhil ibrahim al-ameri) https://doi.org/10.30772/qjes.v13i4.700 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. bearing capacity of square footing resting on layered soil sarah abdul hussein mandeel a , haider m. mekkiyah b , abbas fadhil ibrahim al-ameri c* a m.sc. student, department of civil engineering,university of baghdad,, baghdad, iraq. b assistant professor, department of civil engineering,university of baghdad,, baghdad, iraq. c lecturer, department of civil engineering,university of baghdad,, baghdad, iraq. a r t i c l e i n f o article history: received 17 september 2020 received in revised form 19 october 2020 accepted 19 october 2020 keywords: bearing capacity layered soil plaxis 3d a b s t r a c t the bearing capacity of layered soil studies was carried out with various approaches such as experimental, theoretical, numerical, and combination of them. this work is focused on the settlement and bearing capacity of shallow foundations subjected to the vertical load placed on the surface of layered soils. the experimental part was performed by manufacturing soil cubic container (570 mm x 570 mm x 570 mm). a model square footing of width 60 mm was placed at the surface of the soil bed. the relative density of sand was constant at 60%, and the clay was prepared with a density of 19.2 (kn/m 3 ) and water content of 14.6%. plaxis 3d fem was used to simulate the experimental tests and performing a parametric study. the results showed that there was a good agreement between experimental work and corresponding numerical results. the value of the bearing capacity was obtained from load-settlement curve. the bearing capacity of layered soil showed higher value for footing resting on clay over sand soil. it was found that an increase in the ultimate bearing capacity regarding the clay over sand with increasing in first layer thickness ratio; while, a decrease has been indicated for the sand over clay. the critical depth was found at h = (2-3m), and the failure pattern was not unique for layered soil. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction in geotechnical engineering, the major topic is a behaviour related to shallow foundations on the soil. the ultimate bearing capacity which is related to shallow footings was considered as challenging amongst the geotechnical engineers and researchers. the structure self-weight as well as the applied loading including wind load and live load, should be economically and safely transferred to the soil. the foundation’s ultimate bearing capacity can be well-defined as the load where the shear failure which is related to soil beneath the foundation happens shoaei et al. [1]. so far, a lot of numerical and experimental researches were conducted for determining the bearing capacity regarding shallow foundation on the soils. the majority of bearing calculations of the shallow footings were assessed with the use of a conventional theory where the bearing capacity factors have been used. also, the elasticity theory has been carried out in analysis in which the soil was indicated for being rigid, homogeneous, and isotropic for simplifications in the geotechnical engineering practices. yet, the soils are of different stratums in the earth, they are not homogeneous in nature. at many places, there exists multi-layered soil with different depths and have different soil properties nujid et al. [2]. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 307 the failure mechanism related to the layered soil is on the basis of thickness as well as soil properties of all layers. in a few cases in which the top layer was fairly thick and consisted of the weak soil, the mechanism of the failure might be limited in the top layer, while the strength regarding the rest lower layers won’t have an impact. however, in various other cases, the failure mechanism might include at least two layers zhu et al. [3]. a lot of significant examples exist for the tasks of the foundation engineering where it might be of high importance to involve the impact of soil layers when assessing the bearing capacity. for example, the raft foundations and shallow offshore foundations, typically have large physical dimensions; therefore, the potential failure surfaces might be extending to the considerable distance below the surface of the soil. also, it is indicated that any of the soil layers in such failure surface depths can be affected via failure load. other examples consist of the structures that are placed on the engineered fill layers is a storage oil tank, as well as unpaved roads that are built on the soft clay in which the layer of a compacted fill will be applied for spreading the load applied by passing vehicles ramadan et al. [4]. in this research, lab tests have been performed and finite element simulations of these tests using the finite element program plaxis 3-d were conducted for investigating the ultimate bearing capacity in addition to the settlement and mode of failure layered soil under a vertical central load. 1. previous research 1.1 experimental research carlos et al. [5] used new punching shear failure according to the project area approach that has higher similarity to the actual failure shape. he created a bearing capacity equation with regard to strip footing on the basis of 2-layered soil as a function related to the characteristics of lower and upper soil layers, upper layer’s thickness, footing’s depth/width ratio as well as the failure surface angle in terms of vertical. the suggested equation was designed via the summation of forces induced in addition to being mobilized against the exerted pressure at the chosen strip element that is located in the upper layer of the sand. furthermore, there was wide disagreement for high (h/b) ratio values and good agreement for the small (h/b) ratio values. huang and qin [6] were estimated the bearing capacity for strip footings based on two-layered soil. the failure mechanism is shown in fig. 1. figure 1: the suggested huang and qin (2009) failure mechanism. the process of the analysis which has been developed by huang and qin [6] consists of two fundamental sub processes called compatible velocity field determination and critical failure determination, through which the bearing capacity has been achieved. results for the 2layered soil sand on clay profile will be compared with the ones of hanna and meyerhof [7] and it has been noticed that through the increase of the thickness of the top layer, the discrepancy rises via overestimating huang’s approach. ornek, et. al. [8] performed field test with the use of 7 separate footing diameters up to 0.9 m, in addition to 3 different thickness of the granular fill layers. as the tests have ended, the load–settlement curves were plotted, while the bearing capacity that is related to the circular shallow footings which are supported via compacted granular fill layers over a natural clay soil has been predicted. the work results indicated that there is an increase in the bearing capacity as the foundation size increases and using granular fill layers over the natural clay soil has a significant impact on settlement characteristics and bearing capacity. furthermore, there has been an increase in bearing capacity ratio (bcr) when the granular fill thickness increased for all the footing diameters. ramadan and hussien [4] investigated the behaviour of footing under vertical load on 2-layered soil. the work was carried out for bearing capacity which is related to sand overlying clay, numerical and experimental works were also conducted. the results were presented for the load-settlement curves, the ultimate bearing capacity. moreover, nondimensional relationship for the effect of the upper layer thickness to the ratio of footing width, (h/b), was presented in addition to the strength related to the upper layer soil on bearing capacity. also, the failure modes of the foundation soil system were provided. it has been indicated that ultimate bearing capacity regarding dense sand over medium clay is increased with an increase of footing width (b) and ratio of sand thickness, (h/b), whereas decreasing for the loose sand over medium clay. in addition, there is an increase in sand ultimate bearing capacity over clay with increasing upper sand relative density. the failure pattern is showing punching shear failure in upper dense sand and the local shear failure in lower clay with regard to h/b = 1. the general shear failure has nomenclature b width of footing (m) greek symbols c cohesion of soil (kn m -2 ) ψ dilatancy angle cc coefficient of curvature 𝛾𝑑(max ) maximum dry unit weight of sand (kn m -3 ) cu coefficient of uniformity 𝛾𝑑(min ) minimum dry unit weight of sand (kn m -3 ) d10 the size at 10% finer by weight (mm) ∅ angle of internal friction (degrees) d30 the size at 30% finer by weight (mm) 𝛾 unit weight of soil (kn m -3 ) d60 the size at 60% finer by weight (mm) ν poisson’s ratio dr relative density of sand e young modulus (kn m -2 ) subscripts h thickness of top soil layer (m) fem finite element method h/b ratio (thickness of soil layer to the width of footing) nɣ bearing capacity factor s/b settlement to the footing width ratio 308 sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 been indicated at h/b = 3 and also for the sand bed. furthermore, in upper loose sand at h/b = 1 general shear failure has been indicated that is modified to local shear failures when h/b = 3. misir and laman [9] investigated the bearing capacity related to the circular footings on the granular fill layer which is over the soft clay soil. the bearing capacity has been assessed with the use of empirical estimation approach on the basis of physical modelling on-site and in the laboratory. the statistical analysis was conducted in the case when experimental cases have been complicated and when there are very high costs to construct and monitor full-scale test reservoirs. in addition, from field and laboratory test results, it has been indicated that bearing capacity regarding circular footings on a granular filling layer over the soft clay soil has been increasing up to 78% depending on granular filling layer thickness with regard to various footing diameters. on the basis of comparisons of such formulations as well as field plate load tests, also laboratory results from this work, the results were in good accordance with predicting the convergence’s behaviour via various works in the researches. 1.2 finite element research zhu [3] presented the ultimate bearing capacity associated with rough strip footings which rest on two layers of clay soil as well as subsequent cohesion coefficient (nc). the computations have been achieved via commercial fem software (abaqus). the results were put in comparison with the published limit analysis and showed excellent agreement. from the result, it has been indicated that in the case where a weak clay layer was overlaying strong one nc will be increased with an increase of (h/b). moreover, the magnitude related to nc was verified for approaching 5.146 with regard to all the cases of weak clay on a strong one which is coinciding with the presumptions of failure surface which is limited to the top layer. furthermore, the critical depth has been specified as the depth for which nc approach 5.146 which is related to (h/b) = 2. moayed, et al. [10] presented the bearing capacity regarding ring footings on two layered soil using finite element software, abaqus. the upper layer was soft clay, while the lower layer has been cohesion less sand. in addition, mohr-coulomb plastic yield criterion has been utilized for soil modelling. the effect of the thickness of the clay layers were analyzed. from the result, it is found that bearing capacity is gradually decreased with the increase in clay layer’s thickness. also, with the increase in clay layer, the displacement vectors will propagate in the clay layer and nearly not entering the sand region, and with the decrease of clay layer, the displacement vector was limited in the clay layer. mosadegh and nikraz [11] used the fem approach for calculating the ultimate bearing capacity that is related to a strip foundation on one-layer and two-layer (clay over sand) of soil. the computations have been conducted with the use of abaqus (fem software) for assessing the impact of soil parameters including initial condition, footing roughness, and dilation angel on the soil behaviour. the elastoplastic drucker-prager model is represented the soil behaviour, while the footing material was assumed for being isotropic as well as linear elastic. for a homogeneous soil profile, it is found that the wider and deeper failure mechanism is accumulated under footing with increasing dilation angel. the bearing capacity of the single-layer sandy soil acquired via abaqus is putted to comparison to the acquired via the terzaghi equation. it was indicated that the bearing capacity values with regard to dilation angel for fem analysis is 13% higher than the ones without dilation and. in addition, the bearing capacity obtained by terzaghi has a value among those obtained by fem. reddy and kumar [12] presented the behavior of foundation resting on layered soils under vertical loading conditions. the different failure modes and the foundation deformation patterns have been specified with utilizing a finite element modelling software (plaxis). also, the parameters including the soil layer’s thickness, cohesion, and friction angle were varied for the purpose of studying their impact on failure pattern. different cases such as a clay layer over the sand layer, sand layer over clay layer, and two clay layers with various cohesion values have been assessed through varying the overlying stratum thickness. for each case, the failure patterns are explained. from the result, it is found that when increasing the first layer thickness, the failure pattern related to layered soil will be totally different. in addition, the behavior of the failure pattern when clay overlay sand was significantly different from a vice versa case. furthermore, the cohesion as well as the angle of friction value of the soil also found for altering the failure pattern. 2. experimental tests and materials used the function to achieve the physical model is studying certain features related to the response of the prototype. in addition, the full-scale field tests on the foundations are considered as the best method to the verification and calibration regarding the analytical approaches for certain projects, however, the costs of such experimentations is high and the regulation of parameters of the soil and the evaluation of their impacts on the behavior of soil are difficult in addition to the difficulties related to loading full-scale prototypes until failure. attain small scale laboratory models is considered as another choice. providing the confidence of their validity is the significant aim of a small scale in the experimental models. the scaling effect should be reduced for satisfying the behavior observations at a small scale and the way it might be extrapolating for predicting the behavior of full-scale al-ameri [13]. 2.1 the clay used in this study the clay soil utilized in the presented work was brought from al nahrawan which is a city located 35 km east baghdad, near brick quarries and from a depth of (1.0-1.5) m. the soil samples were collected from small bit as disturbed samples and placed in bags then transferred to the soil mechanics laboratory. the standard tests have been carried out for determining the soil’s geotechnical properties. following carrying out the needed conventional as well as other needed laboratory tests (compaction, plastic and liquid limit, hydrometer and sieve, unit weight, and triaxial test), the soil has been prepared for the model tests. the soil was specified as low-plasticity clay, cl, based on the unified soil classification system (uscs). furthermore, the values related to the plasticity index, liquid limit, and plastics limit of clay have been acquired as 17.4%, 32.6%, and 15.2%, respectively, while the value related to a specific gravity of the clay soil is indicated to be 2.71. the undrained shear strength value of clay soil was 70 kpa as well as the internal friction’s angle was 6 ̊ in dry condition. the dry unit weight in addition to the moisture content have been used as 19.2 kn/m 3 , 14.6%, respectively. 2.2 the sand used in this study the sand soil used in the experimental studies was obtained from karbala city. laboratory tests (direct shear, unit weight, and sieve) have sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 309 been carried out for this soil. all of the conventional test results have been provided in table 1. according to the sieve analysis and uscs, the sandy soil is classified as poor graded sand (sp). table 1: physical and mechanical properties of the soils used physical property result sandy soil uscs-soil type sp d10 (mm) 0.25 d30 (mm) 0.41 d60 (mm) 0.81 cc 0.83 cu 3.24 γdmax (kn/m 3 ) 18.0 γdmin (kn/m 3 ) 15.0 gs 2.71 φ (°) 36.0 c (kn/m 2 ) 0.2 clayey soil uscs-soil type cl gs 2.71 ll, % 32.6 pl, % 15.2 sand (0.075-4.75 mm) % 14 silt (0.005-0.075 mm) % 35 clay (< 0.005 mm) % 51 2.3 preparation of soil layers before preparing the soil bed, trial tests have been conducted for controlling the effectiveness related to the preparation method. the glass container has been marked in 6 sections with a height of (9 cm) for each as can be seen in fig. 2, and with the known value related to dry unit weight that has been needed in this work, the dry soil’s weight might be specified for each one of the layers. figure 2. preparation of soil layered within the glass box. a steel tamping hammer has been utilized for compacting the soil through uniformly distributed blows for getting the needed density. for preparing the medium state sand layer with relative density (60%) which is utilized in this work, the sand has been poured in a box from a specific height and then tamping lightly. also, a hygroscopic water content ( 0.53%) has been added to the sand before compaction and pouring for ensuring small cementation of the soil prior to tests das [14]. on the other hand, the clayey soil was prepared at a dry unit weight of (19.20 kn/m 3 ) and with a corresponding (14.6%) water content to get undrained shear strength (c = 70 kpa). the natural clay was left for air-drying and pulverized by a hammer to small sizes. the dry clay was divided into groups; each group of known weight was mixed with water and kneaded by hand well. after mixing with water, the soil lumps were expelled out of the container and tamped with a steel hammer. the procedure continued until the required thickness of the bed was achieved. 2.4 container box and testing procedure a cubic test box having 570 x 570 mm in plan and 570 mm in depth is utilized in experimental tests. the test box has been made of glass, with (15mm) as wall thickness. the aim of using glass is to allow better observation of soil homogeneity also a reference marker was used in the front side of the tank to help with the formation of the required layered model. in each model test, the test container was placed on the steel base of the compression machine and the soil bed was prepared as per in section 3.3. after filling the container with a controlled density soil, the rigid square steel base plate with dimensions of 60 x 60 x 10 mm has been placed on the surface related to soil bed at the centre of the model. a small spherical hole was made by carving the centre of the footing surface to ensure transferring the vertical load to the centre regarding the foundation with a steel ball. after that, the footing was loaded by the compression machine with a digital control system until the failure occurred. the loading process was controlled by the strain control technique and the loading rate was 1.0 mm/min. the load has been read from a digital weighing indicator that is connected to the load cell as can be seen in fig. 3. the average vertical settlement has been measured using a dial gauge with 0.01mm accuracy and a 30 mm stroke attached vertically on the surface of the footing. a magnetic holder was used to fix the dial gauge on the loading frame. fig. 3 shows the experimental setup which has been utilized for performing the tests. figure 3. the experimental setup used to perform the tests. 3. test variables the total number of conducted tests is 10 models. there are two main parts in the testing program, the first one is concerned with one-layer models (homogenous) with regard to clayey and sandy soil with the total number of tests of two, while the other one is concerned with a two-layer 310 sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 model (non-homogenous) of soil with a total number of tests of eight models. four of these were performed in clay over the sand model, and the other ones are concerned with sand over the clay model. the thickness of the first layer was varied from h/b = 1 to h/b = 6 (h/b = 1, 2, 3, 6). some of the testing setup of soil models is given in fig. 4. figure 4: some of the tests of soil models. 4. finite element simulation the experimental and numerical studies are considered in this study to accomplished each other in the field of geotechnical engineering. finite element modelling has more advantages than experimental modelling for foundation analysis due to the parameters that may be easily varied and the details related to stresses as well as deformations throughout the system might be examined, in addition to the overall cost effective of such analyses. however, a 3-d finite element simulation for the experimental tests, utilizing plaxis 3d program, has been carried out for examining the actual behavior of the layered soil system. actually, this step is regarded as a first step of the researchers’ goals to make an intensive fullscale parametric study. 4.1 geometry and meshing firstly, a geometric model of dimension is created. the same internal dimensions that are related to the model box of laboratory tests have been utilized in numerical work for the purpose of simulating similar boundary condition, therefore the model dimensions have been (570 mm × 570 mm × 570 mm) defined via single borehole at the model’s first corner. the borehole was defined as a location in model which have information related to the soil profile. in addition, the hydraulic head was under soil profile due to the fact that the water condition was not considered in the model. the loading is carried by a rigid surface plate square footing of (60mm × 60mm). a fine mesh is generated in the geometry. the model geometry and meshing are shown in fig. 5. a point prescribed displacement is created at the centre of the footing to same settlement obtained from experimental work. the calculations were continued until the prescribed displacement of the soil reach to 20% of the footing width. furthermore, the loadsettlement curve acquired from output provided settlement of footing and ultimate bearing capacity. the same procedure is adopted for all models. figure 5: the model geometry and meshing for two-layered soil. 4.2 modeling and parameters the footing has been modelled as a linear elastic material, while the soil is modelled in the moher-coulomb model. material models and the input parameters of the fem program are shown in table 2. in the finite element method, the displacement control approach is utilized to evaluate the load-settlement curve. in this approach, the load required to reach the desired displacement can be determined. the loading was stopped after settlement = 20% of the footing width, (s/b = 20%). table 2. input parameters for the fem program parameter sand clay footing material model mohrcoulomb mohr-coulomb linear elastic material behaviour drained undrained (a) non-porous unit weight, γ, kn/m3 16.67 19.2 77.03 young’s modulus, e, kn/m2 30000 10000 193*106 poisson’s ratio, ν 0.30 0.35 0.15 cohesion, c, kn/m2 0.2 70 ___ friction angle, ø 36 6 ___ dilatancy angle, ψ 6 0 0 5. results and discussions of experimental tests and fem simulation it is well known that a wide range of the results can be obtained from the plaxis-3d 2013 software, but the output was limited to what needed for the comparison with experimental tests. the load-settlement relationships of the footing were obtained from loading tests of both experimental and fem work and provided in fig. 6, 7, and 8. the value related to the soil’s ultimate bearing capacity from load-settlement curve defined according to (0.1b) is shown in table 3 for the illustration of the comparison between the experimental and fem results. it can be seen that both of the experimental work and fem modelling give almost the same behaviour. there are two tests on homogeneous soils (clay having c = 70 kpa and sand with dr= 60%), were performed. fig. 6 is providing the loadsettlement responses related to the homogeneous foundations. generally, the homogeneous beds showed nonlinear load-settlement variations. a comparison between the theoretical bearing capacities those estimated with the use of general bearing capacity equation (qu=c nc fcs fcd fci +q nq fqs fqd fqi + 0.5 b ɣ nɣ fɣs fɣd fɣi) balla [15] with bearing capacities acquired from the experiment tests was carried out. it can be sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 311 indicated that the ultimate bearing capacities for clay was (597 kpa) and for sand was (16.8 kpa), as is evident, the sand's bearing capacity obtained from experimental work is much higher than its value extracted by the equation. the bearing-capacity model tests that are related to the shallow footings conducted in different geotechnical laboratories specified that the test results of the model on granular soil were generally high in comparison to those estimated via conventional approaches [16], [17], [18], [19], [20], [21], [22], [23]. this happens due to a few reasons, the major one is the un-predictability related to nɣ as well as the scale effect related to model tests. several studies compiled by (debeer, 1965) [24] about the bearing capacity test results have been illustrated in fig. 9 as plot of nɣ versus ɣb. also, as ɣb increased, the value of nɣ will be quickly decreased. the layered foundations consisted of clay of different thicknesses (h=1b-2b-3b-6b) overlying sand and vice versa. eight tests on two layeres of soil were performed. it might be indicated that the homogeneous clay bed showed a stiff load–settlement response in comparison to the sand bed. thus, the layered foundations which have clay beds of c = 70kpa at the top surface, might be considered as stiffer soil overlain the softer soil; and vice-versa in case of sand over clay. this result is in good agreements with observations of biswas & krishna (2017) plaxis manual [25]for foundations with softer layer overlying stiffer layer. in fig. 7, the load–settlement responses related to sand over clay foundations were provided. from the numerical and experimental observations (for softer soil which overlies through stiffer soil), the maximum bearing capacity has been indicated by approximately 70.9 kpa for h = 1b at s/b = 10%. with regard to h ≥ 3b, the bearing capacity was very much similar, with bearing capacity regarding homogeneous sand where it was approximately 54 kpa (in spite of the layer thickness variations, h/b). high bearing capacity related to h = 1b is due to the impact of more support for the sand layer obtained from underlying stiff clay. generally, for sand layer of small thickness (h ≤ 3b), the failure surface will be extending to the lower layer; while, for thick layers (h > 3b), the failure surface will completely develop in top layer. fig. 8 shows the load–settlement curve of the clay over sand foundations. in these cases, the load-settlement responses have shown an increase in bearing capacity for the layer of clay overlying sand; where the large effect is indicated for stiff clay soil, regardless of variations in clay layer thickness (h). the results for the two-layer soil shown in fig. 6 and 7 show that with increasing thickness ratio h/b, the bearing capacity of clay over sand increases, considering that bearing capacity of clay higher than that of sand whereas it decreases for sand over clay. when h/b ≥ 3 the lower soil doesn’t affect the bearing capacity and the soil behaves as one layer of soil. it is found that the failure pattern of layered soil is to be entirely different as the thickness of the first layer increases as shown in fig. 10. figure 6. the experimental and numerical load-settlement curve of one layer of soil. figure 7. the experimental and numerical load-settlement curve of sand over clay layered. 312 sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 figure 8. the experimental and numerical load-settlement curve of clay over sand layered table 3. values of ultimate bearing capacity, qu and the corresponding settlement ratio, s/b %. type of soil model h/b qu (kpa) exp. qu (kpa) fem. sand * 55.6 60.7 clay * 454.2 519.0 sand over clay 1 70.9 84.8 2 64.8 76.8 3 54.2 63.0 6 54.0 61.6 clay over sand 1 357.3 447.0 2 432.0 514.2 3 443.2 515.0 6 448.7 517.5 (*) one layer of soil figure 9. variation of nγ with γb (adapted after debeer, 1965) figure 10. failure pattern for the case of clay over-sand. 6. conclusions  for a layered foundation, the load-settlement responses showed higher bearing capacity values for stiffer subgrades.  for this study, there was an increase in the ultimate bearing capacity of clay overlying sand with increasing clay thickness ratio, h/b; while, there was a decrease in cases of sand overlying clay with the increase in sand thickness ratio.  the critical depth in this study, where the strength related to the bottom layer has no impact on the bearing capacity of the entire model is exist at h/b = (2-3).  there is an excellent accordance between the experimental work as well as the corresponding numerical results using plaxis (3d) software, indicating that the numerical modelling used in this work for simulating the foundation behaviour on homogeneous and nonhomogeneous soil is successful.  the pattern of failure of the layered soil is completely different as the first layer’s thickness increases. in addition, the behaviour of failure pattern when clay overlay sand was significantly different from a vice versa case. references [1] m. d. shoaei, a. alkarni, j. noorzaei, m. s. jaafar and b. b. k. huat, review of available approaches for ultimate bearing capacity of twolayered soils, journal of civil engineering and management, 18(4), p. 469–482, (2012). [2] m. m. nujid and m. r. taha, a review of bearing capacity of shallow foundation on clay layered soils using numerical method, ejge journal, vol. 19, pp. 811-824, (2014). [3] m. zhu, bearing capacity of strip footings on two-layer clay soil by finite element method, in proc. of the abaqus users’ conference, massachusetts, boston, p. 776–787, june (2004). [4] m. i. ramadan and m. h. hussien, bearing capacity of sand overlying clay – strip footing, international journal of science and research (ijsr), vol. 4, no. 11, pp. 1852-1859, (2015). [5] a. f. carlos, ultimate bearing capacity of shallow foundations on layered soils, msc thesis, civil and environmental engineering. quebec: concordia, (2004). [6] m. huang and h.-l. qin, upper-bound multi-rigid-block solutions for bearing capacity of two-layered soils, computers and geotechnics, p. 525– 529, (2009). [7] m. ornek, m. laman, a. demir and a. yildizd, prediction of bearing capacity of circular footings on soft clay stabilized with granular soil, the japanese geotechnical society. production and hosting by elsevier, pp. 69-80, (2012). sara. a.mandeel, haider. m. mekkiyah, abbas. f. al-ameri /al-qadisiyah journal for engineering sciences 13 (2020) 306–313 313 [8] g. misir and m. laman, a modern approach to estimate the bearing capacity of layered soil, periodica polytechnica. civil engineering, p. 434–446, (2017). [9] r. z. moayed, v. rashidian and e. izadi, evaluation on bearing capacity of ring foundations on two-layered soil, world academy of science, engineering and technology, vol. 6, (2012). [10] mosadegh and nikraz, bearing capacity evaluation of footing on a layered‐ soil using abaqus, journal of earth science & climatic change, (2015). [11] v. s. k. reddy and d. t. k. kumar, behaviour of foundation in layered soils, international journal of science and research (ijsr), vol. vol. 7, issue 1, (2018). [12] d. wood, geotechnical modeling, abingdon, oxfordshire, spon press, (2004). [13] a. f. i. al-ameri, transient and steady state response analysis of soil foundation system acted upon by vibration, phd. thesis, civil engineering department, university of baghdad, (2014). [14] b. m. das, principles of foundation engineering, seventh edition, (1997). [15] a. balla, bearing capacity of foundations, journal of soil mechanics and foundoundation div., asce, pp. 13-34, (1962). [16] d. m. milovic, comparison between the calculated and experimental values of the ultimate bearing capacity, proc., 6th icsmfe, montreal, pp. 142-144, (1965). [17] b. zadroga, bearing capacity of inclined subsoil under a foundation loaded with eccentric and inclined forces: part 1-method review and own model tests. archive of hydroengrg. 22(3/4), pp. 333-336, (1975). [18] w. cichy, e. dembicki, w. odrobinski, a. tejchman and b. zadroga, bearing capacity of subsoil under shallow foundations: study and model tests, scientific books of gdansk technical university, civil engineering, pp. 1-214, (1978). [19] a. bolt, bearing capacity of a homogeneous subsoil under rigid footing foundation loaded with inclined and eccentric force, in~ynieria morska, 3(2), pp. 108-110, (1982). [20] t. s. ingra and g. b. baecher, uncertainty in bearing capacity of sands, j. geotech. eng., asce, vol. 109(7), pp. 899-914, (1983). [21] s. shiraishi, variation in bearing capacity factors of dense sand assessed by model loading tests, soils and found. journal, vol. 30(1), pp. 17-26, (1990). [22] j. hartikainen and b. zadroga, bearing capacity of footings and strip foundations: comparison of model test results with eurocode 7, proc., of 13th icsmfe, new delhi, india, no. 2, pp. 457-460, (1994). [23] e. e. debeer, bearing capacity and settlement of shallow foundations on sand, proceedings, symposium on bearing capacity and settlement of foundations, duke university, pp. 15-33, (1965). [24] a. biswas and a. m. krishna, behaviour of circular footing resting on layered foundation: sand overlying clay of varying strengths, international journal of geotechnical engineering, pp. 1-16, (2017). [25] plaxis manual, (2013). article al-qadisiyah journalfor engineering sciences15 (2022) 241–246 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address:amn11872@gmail.com (eman m. saasaa) https://doi.org/10.30772/qjes.v15i4.878 2411-7773/©2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. reducing the viscosity of missan heavy crude oil using combinations of low molecular weight hydrocarbon compounds eman m. saasaaa*, rafid k.abbasa and suzanne alsamaqb adepartment of chemical engineering, college of engineering, university of al-qadisiyah, iraq binstitute of foundation studies,, arden university, coventry, uk a r t i c l e i n f o article history: received 14 august 2022 received in revised form 2 november 2022 accepted 13 december 2022 keywords: heavy crude oil transportation viscosity reduction a b s t r a c t this work studied the facilitation of the transportation of missan heavy crude oil characterized with high viscosity 84.61 cp at 15 °c, low api 23.1, by reducing its viscosity from break down asphaltene agglomerates using five solvents with some novel combinations of chemical additives were used for this study (naphtha & toluene, naphtha & xylene, naphtha & kerosene, toluene & kerosene, and xylene & kerosene).the viscosity of crude oil was measured after being treated with these chemicals at different concentrations (4, 8, and 12 weight%) and temperatures 15, 25, 35, and 45 °c. it has been found that increasing the concentration of naphtha with xylene from 4% to 12% causes a decrease in viscosity, from 48.62 cp at 15°c to 30.11 cp. the viscosity of a mixture of naphtha and kerosene drops from 50.15 cp at 15°c to 31.70 cp when the concentration is raised from 4% to 12%. the addition of toluene to kerosene causes the viscosity to drop from 51.76 cp at 15°c to 33.67 cp when the concentration of toluene is raised from 4% to 12%. increasing the xylene concentration from 4% to 12% in kerosene led to a decrease in viscosity from 53.65 cp at 15°c to 34.88 cp at the same temperature. the findings of the present work could be applied to the petroleum industry for the purpose of transporting heavy oil of missan or any other heavy crude. ©2022university of al-qadisiyah. all rights reserved. 1. introduction transportation of petroleum is now a highly specialized and complex. high viscosity fluids are a major challenge in pipeline transportation because they necessitate efficient and cost-effective methods of transporting heavy crude. heavy crude oils have a density that meets or exceeds that of water. they can range in consistency from a thick molasses to a solid at room temperature, with the former being the most common. it is difficult to transport heavy crude oil due to the presence of metals such as nickel and vanadium, as well as high sulfur content. the production, separation, transportation, and refinement of crude oil can be complicated by the complexity of crude oil [1]. as the name suggests, heavy crude has a high viscosity, specific gravity, and molecular composition. because of the high concentration of naphthenes and paraffins, it is thick and viscous [2].there are higher proportions of high-boiling constituents in heavy crude oil, such as greases and waxes, as well as residue from lubricating oils, lubricants, engine oils, cylindrical oils, and gear oils, in heavy crude oil (residual fuel oils, coke, tar and asphalt). heavy petroleum also contains more aromatic and heteroatom-containing compounds (n, o, s, and metals) than light petroleum [3]. there are numerous costly issues with production loss and transportation difficulties that make this type of asphalting a vexing problem for those in the petroleum industry. in terms of recoverable oil reserves, heavy crudes account for a significant portion of the global total. they range in viscosity from 100 to more than 105 mpas at room http://qu.edu.iq/ mailto:eng.chem.20.post.18@qu.edu.iq https://doi.org/10.30772/qjes.v15i4.878 http://creativecommons.org/licenses/by/4.0/ 242 eman m. saasaa and rafid k. abbas /al-qadisiyah journal for engineering sciences 15 (2022) 241–246 temperature. an ideal condition for crude oil pipeline viscosity is 400 millipoise pounds per square inch (mpas) [4-5]. heavy oil's high viscosity is a critical factor that has a significant impact on the extraction, surface transportation, and refinement processes upstream and downstream. finding more efficient and cost-effective ways to recover heavy oil and reduce the associated investment and operating costs can be greatly aided by gaining a enhanced thoughtful of the causes of its high viscosity [6]. heavy crude oil can be transported through pipelines in a less viscous state in a number of different ways. oxidation and drag can be reduced through a variety of more general methods, including upgrading, diluting, heating, and using surfactants to stabilize emulsions. in order to overcome the difficulties of transporting heavy oil by pipeline, heating is a common method [7]. dilution is approach that has been widely employed to reduce the viscosity of heavy crude oil. the dilution process is performed by adding condensates, hydrocarbon liquids that are lighter in weight or alcohols, to heavy oil. this method is useful for lowering viscosity and increasing fluid flow in the reservoir and the pipeline [8]. examined the influence of two diluents on reducing heavy oil viscosity to increase oil recovery. two oil samples were used including a diesel based heavy oil, and light oil sample. the diluents were oil based and thus had a high solubility in the oil [9]. attempted to clarify the mechanism of viscosity reduction using metal-lug and compounds by using iron iii para-toluene sulfonate at varying degrees of heat and pressure. the main drawback of the chemical was the cost and the availability [10]. examined the effect of different gasses including methane, carbon dioxide, and propane on the reduction of oil viscosity at different pressures and temperatures. he found that dissolving the gasses with the heavy oil using the same molar concentration will result in an almost equal reduction in oil viscosity [11]. proposed combining naphtha and kerosene in varying proportions. iraqi heavy crude oil is blended with naphtha and kerosene at varying concentrations ranging from three to twelve weight percent to lower the oil's viscosity and increase its flow ability. heavy oil can also be transported by heating it, as its viscosity rapidly decreases at higher temperatures. as the oil is heated, its viscosity is reduced, making it easier to pump. this is the underlying principle of this method. as a result, it's critical to reduce the oil's viscosity by heating it to a high temperature. over long distances, the capital and operational costs of a heated pipeline are a major drawback [12]. underwater transportation of heavy oil through a heated pipeline presents significant challenges due to the cooling effect of the surrounding water and the manageable difficulties of maintaining pumping stations and heating stations [13-14]. asphaltenes, the oil's most polar and/or heavy constituents, have been shown in several experiments to have a significant impact on heavy oil viscosity in terms of volume fraction, chemical structure, and physical chemical [15]. crude oil heavy components that are insoluble in nonpolar solvents have a solubility class called petroleum asphaltenes. oil-derived asphaltenes can be found as colloidal dispersions that have been stabilized with the help of additional crude oil constituents. a wide range of mechanistic and physicochemical factors involved in oil scope recovery and production can easily disturb these naturally occurring dispersion systems. increased asphaltene destabilization is caused by a variety of factors including changes in heat and pressure, the blend of crude and condensate streams, as well as better recovery methods. there are numerous issues for crude oil producers when asphaltenes are built up on the surface [16]. asphaltenes have been found to have properties that are similar to those of colloids in some studies. in the heavy oil matrix, micelles of these colloids can be seen. the micelles in petroleum are more resin-rich because the mole part of resins is larger than that of asphaltenes. aggregates begin to form at a concentration known as the "critical micelle concentration" (cmc) in asphaltenes. for asphaltene degradation to occur in response to polar solvents it is reasonable to assume a decrease in hydrocarbon medium polarity (or solubility parameter) [17-18]. as a result of the interaction between different asphaltene species, micelles are thought to form. we don't know exactly how asphaltene micelles can be formed due to the interaction of intermolecular or intramolecular forces. possible interactions include: porphyrin interaction, electron transfer between aromatics (-bonding), porphyrin-aromatic hydrogen bonding, porphyrinporphyrin hydrogen bonding, and porphyrin-porphyrin dipole-dipole interaction [19-20]. the purpose of this study is to examine the reduction of viscosity of heavy crude oil obtained from missan oil field using formulations of different hydrocarbons (naphtha, toluene, xylene, kerosene) with different concentrations (4, 8 and 12 wt%) and different temperatures (15 °c to 25 °c, 35 °c, and 45 °c) and thus increasing oil production and reducing transportation problems and costs. 2. experimental work 2.1 feedstock the feedstocks in this research was missan crude oil, acquired from amara oil fields. these are some of the characteristics of the crude oil are specified in table 1. table 1. properties of heavy crude oil from amara field before treatment light naphtha al-diwaniya refinery provided the dynamic viscosity and density light naphtha 0.41 (cp) and 0.6950 g/cm3, respectively. toluene solvent (c7h8) toluene was obtained from the al-diwaniya refinery, and its molecular weight, boiling point, and density are (92.14 kg/mole, 110-111 °c, and 0.870 g/cm3). xylene solvent (c8h10) the al-diwaniya refinery provided the xylene, which has a molecular weight of 106.17, a boiling point of 136-140 °c, and a density of 0.860 g/cm3. kerosene solvent al-diwaniya refinery supplied the kerosene, which had a property value api gravity at 15.6 c 23.100 sp.gravity at 15.60 c 00.915 density at 15 c 00.915 kin. viscosity (cst). at 37.8 c̊ 34.100 water content (%vol.) 07.000 salt content (% wt) 03.670 salt content ppm 7139.3 sulfur content (%wt) 03.670 asphaltenes (%wt.) 05.420 243 eman m. saasaa and rafid k. abbas /al-qadisiyah journal for engineering sciences 15 (2022) 241–246 dynamic viscosity of 1.79 (cp) and a density of 0.7884 (g/cm3). 2.2 devices a) viscometer:to determine the viscosity of the oil mixed with the different additives using a device dv-e viscometer(brookfield ,usa made) as shown in fig. 1. b) hot plate: the vessel containing the oil was placed in the hot plate to be heated to the desired temperature and at desired rotary speed as shown in fig. 2. c) thermometer: used to measure the core temperature of the oil after heating to ensure that the temperature reached the requiredvalue. d) various containers and beakers as well as stirrer device with magnet rotation were used in the current study. figure 1. dv-eviscometer used for viscosity measurements. figure 2. hotplate used in the experimental work. 2.3 procedure 2.3.1 mixing the spindle of a dv-e (dynamic viscometer class e) is rotated in a circle during operation. in milli pascal or centipoises, the dv-e viscometer reads viscosity. depending on the setting, the viscometer was either set to speed or spindle selection. the speed of rotation can be set by the user. once the set is in the correct position, the operator can select the spindle by moving it to the left. the dv-e viscometer comes with a set of four spindles. a unique entry code number is required for each spindle before the viscosity value can be calculated. in total, the dv-e viscometer offers 18 different rotational speeds, from 0.3 to 100 rpm, for measuring viscosity. crude oil's viscosity can be determined using the following steps: • a beaker with 200 ml of crude oil poured init. • increasingtemperaturefrom 15 degrees celsius to 25, 35 and 45 degrees celsius by using the heater of the hot plate. • monitoring the viscosity of the oil over a range of temperatures. • finally, a mixture of chemical additives such as (naphtha & toluene, naphtha & xylene, naphtha &kerosene , toluene & kerosene and xylene & kerosene ) are added to the heavy crude oil at various concentrations and temperatures in order to observe the changes in viscosity. • for this experiment, a stirrer device that rotated using magnetswasapplied, so that the volatile components of crude oil would not be disturbed. after 15 minutes of mixing, the mixture is declared homogeneous. • a thermometer should be used to make sure that the beaker's interior remains at room temperature throughout your experiment. • the shear rate (speed) of the dv-e viscometer has been set at 100 rpm. • to get the most accurate results, the proper spindleshould be used. • at each temperature, the viscosity was measured by running a test at a set speed. 3. results and discussions the investigation conducted to lessen the viscosity of missan heavy crude oil through the oxidation of asphaltenes at various temperatures and concentrations of hydrocarbons of low molecular weight yielded the following findings: missan heavy crude oil's viscosity reduction was analyzed as a function of the concentration of combination solvents used and the temperature at which they were applied. the figures 3, 5, 7, 9, and 11 display the impact on crude oil viscosity at various temperatures of varying concentrations of (naphtha and toluene), (naphtha and xylene), (naphtha and kerosene), (toluene and kerosene), and (xylene and kerosene). as the concentration of the solvent increased, the viscosity decreased. naphtha and toluene are the most decrease. it was necessary to introduce the viscosity reduction percentage vr percent in order to gauge the degree to which viscosity had been reduced and it was calculated by eq. 1 [21]. 𝐷𝑉𝑅% = [(ηr − ηc)/(ηr)] ∗ 100 (1) where ηr and ηc crude oil cp viscosity reference and its corresponding. the percentage reduction in viscosity versus temperature for various solvent concentrations and temperatures is shown in figures 4, 6, 8, 10, and 12. 244 eman m. saasaa and rafid k. abbas /al-qadisiyah journal for engineering sciences 15 (2022) 241–246 figure 3. effect of naphtha & toluene weight fraction on the viscosity of missan crude oil. figure 4. effect of naphtha & toluene weight fraction on viscosity reduction of missan crude oil. figure 5. effect of naphtha & xylene weight fraction on the viscosity of missan viscous oil. figures 3 and 4 show that naphtha and toluene gave the best viscosity reduction at 45 °c; naphtha and toluene are strong solvents with a high ability to disperse asphaltene agglomerates. as shown in figures 5 and 6, naphtha and xylene were the second best viscosity reducers, where the viscosity decreases from 48.62 to 30.11 at 15°c. after naphtha & xylene, a combination of naphtha and kerosene was used to investigate the viscosity drop as shown in figures 7 and 8 where the third best viscosity reducers, as the viscosity decreases from 50.15 to 31.70cpat 15°c. figure 6. effect of naphtha & xylene weight fraction on viscosity reduction of missan heavy crude. figure 7. effect of naphtha & kerosene weight fraction on the viscosity of missan viscous crude oil as shown in figures 9 and 10, the combination of toluene and kerosene was found to be as the second less viscosity reducers, where the viscosity decreases from 51.76 to 33.67cp at 15°c. 243 eman m. saasaa and rafid k. abbas /al-qadisiyah journal for engineering sciences 15 (2022) 241–246 figure 8. effect of naphtha & kerosene weight fraction on viscosity reduction of missan heavy oil. figure 9. effect of toluene & kerosene weight fraction on the viscosity of missan heavy crude oil. figure 10. effect of toluene & kerosene weight fraction on viscosity reduction of missan crude oil. as shown in figures 11 and 12, xylene & kerosene was found to be asthe less viscosity reducers amongother combinations, where the viscosity decreases from 53.65 to 34.88 cp at 15°c ; in all cases, the solvent formulations listed here are powerful solvents that are capable of dispersing asphaltenes. figure 11. effect of xylene & kerosene weight fraction on viscothe sity of missan viscous crude oil. figure 12. effect of xylene & kerosene weight fraction on viscosity reduction of missan heavy crude oil. 4. conclusions various chemicals were used in this study to evaluate their ability to reduce missan heavy oil viscosity in hopes of increasing oil recovery and oil transportation. the main conclusions from the current research are summarized below: • among all the chemical combinations being used in theresearch, it was concluded that the combination of naphtha and toluene is thmost effective viscosity reducer for missan heavy crude oil compared to other chemicals being tested. • following, the combinations of naphtha and toluene, naphtha and 245 246 eman m. saasaa and rafid k. abbas /al-qadisiyah journal for engineering sciences 15 (2022) 241–246 xylene are the second most effective viscosity reducer then followed by naphtha and kerosene, and finally xylene and kerosene which showed low viscosity reduction effect. • it is worth mentioning that covering the beaker during the experimental work of viscosity measurements gives more accurate resultsof viscosity, due to the reason for controlling the volatility of fumes during heating. • during mixing, the rotation speed should be reduced toabout 300 rpm with a period of 15 min to ensure the best reading for viscosity is obtained. acknowledgment the authors like to express their thanks and gratitude to the faculty of engineering, university of al-qadisiyah, for their support. references [1] speight, j. g. 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[7] hasan, s. w., ghannam, m. t., &esmail, n. (2010). heavy crude oil viscosity reduction and rheology for pipeline transportation. fuel, 89(5), 1095-1100. [8] alboudwarej, h., mohan, j., gozalpour, f., & jarvis, s. s. (2018, april). extra heavy oil production using dilution: viscosity measurement and modeling. in spe western regional meeting.onepetro. [9] xu, y., ayala-orozco, c., & wong, m. s. (2018, april). heavy oil viscosity reduction using iron iii para-toluenesulfonatehexahydrate. [10] freitag, n. p. (2018). similarity of the effect of different dissolved gases on heavy-oil viscosity. spe reservoir evaluation & engineering, 21(03), 747-756. [11] khalaf, a. n., abdullah, a. a., & al-sabur, r. k. (2021). effect of temperature on the performance of naphtha and kerosene as viscosity reduction agents for improving flow ability of basrah-iraq heavy crude oil. journal of advanced research in fluid mechanics and thermal sciences, 84(1), 135-147. [12] shah, a., fishwick, r., wood, j., leeke, g., rigby, s., & greaves, m. (2010). a review of novel techniques for heavy oil and bitumen extraction and upgrading. energy & environmental science, 3(6), 700-714. [13] santos, r., loh, w., bannwart, a. c., &trevisan, o. v. (2014). an overview of heavy oil properties and its recovery and transportation methods. brazilian journal of chemical engineering, 31, 571-590. [14] abdel-raouf, m. e. s. (2012). factors affecting the stability of crude oil emulsions. crude oil emulsions–composition, stability and characterization. croatia: intech, 183-204. article al-qadisiyah journal for engineering sciences 14 (2022) 169–177 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mjdeskandari@gmail.com (majid eskandari shahraki) https://doi.org/10.30772/qjes.v14i3.734 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. bending, buckling and vibration analysis of third order shear deformation nanoplate based on modified couple stress theory majid eskandari shahrakia*, mahmoud shariatib, naser asiabanc, mohsen heydari benid, mohammad reza zamanie, jafar eskandari jamf a department of aerospace engineering, ferdowsi university of mashhad, mashhad, iran. b,c department of mechaniacl engineering, ferdowsi university of mashhad, mashhad, iran. d,e,f faculty of materials and manufacturing technologies, malek ashtar university of technology, tehran, iran a r t i c l e i n f o article history: received 7 august 2021 received in revised form 25 october 2021 accepted 5 november 2021 keywords: modified couple stress theory third order shear deformation each rectangular nanoplate navier type solution a b s t r a c t in this paper a third order shear deformation rectangular nanoplate with simply supported boundary conditions is developed for bending, buckling and vibration analysis. in order to consider the small-scale effects, the modified couple stress theory, with one length scale parameter, is used. the bending rates and dimensionless bending values under uniform surface traction and sinusoidal load, the dimensionless critical force under a uniaxial surface force in x direction and dimensionless frequencies are all obtained for various plate's dimensional ratios and material length scale to thickness ratios. the governing equations are numerically solved. the effect of material length scale, length, width and thickness of the nanoplate on the bending, buckling and vibration ratios are investigated and the results are presented and discussed in detail. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the atomic and molecular scale test is known as the safest method for the study of materials in small-scales. in this method, the nanostructures are studied in real dimensions. the atomic force microscopy (afm) is used to apply different mechanical loads on nanoplates and measure their responses against those loads in order to determine the mechanical properties of the nanoplate. the difficulty of controlling the test conditions at this scale, high economic costs and time-consuming processes are some setbacks of this method. therefore, it is used only to validate other simple and low-cost methods. atomic simulation is another solution for studying small-scale structures. in this method, the behavior of atoms and molecules is examined by considering the intermolecular and interatomic effects on their motions, which eventually involves the total deformation of the body. in the case of large deformations and multi atomic scale the computational costs is too high, so this method is only used for small deformation problems. http://qu.edu.iq/ mailto:mjdeskandari@gmail.com%20(majid https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 170 majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 given the limitations of the aforementioned methods for studying nanostructures, researchers have been looking for simpler solutions for nanostructures. modeling small-scale structures using continuum mechanics is another solution to this problem. there are a variety of sizedependent continuum theories that consider size effects, some of these theories are; micromorphic theory, microstructural theory, micropolar theory, kurt's theory, non-local theory, modified couple stress theory and strain gradient elasticity. all of which are the developed notion of classical field theories, which include size effects. daghigh et al, studied the nonlocal bending and buckling of agglomerated cnt-reinforced composite nanoplates. they investigated the effect of the parameters, such are degree of agglomeration, nonlocal material scale parameter, temperature, foundation properties, volume fraction of cnts, and length-to-thickness aspect ratio for the plate [19]. daikh et al, studied a novel nonlocal strain gradient quasi-3d bending analysis of sigmoid functionally graded sandwich nanoplates. they investigated the effect of the elastic foundation models, sigmoidal distribution index constant, configuration of sandwich plate, material and length nanoscales, boundary conditions on the static deflection [20]. ruocco et al, studied the buckling analysis of elastic–plastic nanoplates resting on a winkler–pasternak foundation based on nonlocal third-order plate theory. they investigated the effect of geometrical, constitutive, and nonlocal parameters on the critical behavior of plates with different boundary conditions [21]. banh-thien et al, studied the buckling analysis of non-uniform thickness nanoplates in an elastic medium using the isogeometric analysis. they discretized the governing equation into algebraic equations and solved by using iga procedure to determine the critical buckling load. by using the non-uniform rational b-splines, iga easily satisfies the required continuity of the partial differential equations in buckling analysis [22]. in this paper, size-dependent nanoplate model is developed to account for the size effect. hamilton principle is used to derive the equations of motion based on the mentioned theories (i.e. modified couple stress and third order shear deformation theories). in order to investigate the effects of material length scale parameter on deflection, buckling and frequency, analytical solution for a static problem is obtained for a simply supported plate and results are discussed. 2. modified coupled stress theory in 2002 yang et al. [1] proposed a modified couple stress model by modifying the theory proposed by toppin [2], mindlin and thursten [3], quitter [4] and mindlin [5] in 1964. the modified couple stress theory consists of one material length scale parameter for projection of the size effect, whereas the classical couple stress theory has two material length scale parameters. in the modified couple stress theory the strain energy density in the three-dimensional vertical coordinates for a body bounded by the volume v and the area ω [6], is expressed as the follows: 𝑈 = 1 2 ∫ (𝜎𝑖𝑗 ℇ𝑖𝑗 + 𝑚𝑖𝑗 𝜒𝑖𝑗 )𝑑𝑉𝑣 𝑖, 𝑗 = 1,2,3 (2.1) were, ℇ𝑖𝑗 = 1 2 (𝑢𝑖,𝑗 + 𝑢𝑗,𝑖 ) , 𝜒𝑖𝑗 = 1 2 (𝜃𝑖,𝑗 + 𝜃𝑗,𝑖 ) (2.2) χ ij and ℇij are the symmetric parts of the curvature and strain tensors and θi and ui are the displacement and the rotational vectors, respectively. 𝜃 = 1 2 𝐶𝑢𝑟𝑙 𝑢 (2.3) σij, the stress tensor, and mij the deviatory part of the couple stress tensor, are defined as: 𝜎𝑖𝑗 = 𝜆ℇ𝑘𝑘 𝛿𝑖𝑗 + 2𝜇ℇ𝑖𝑗 , 𝑚𝑖𝑗 = 2𝜇 𝑙 2𝜒𝑖𝑗 (2.4) where λ and μ are the lame constants, δij is the kronecker delta and 𝑙 is the material length scale parameter. from equations (2.2) and (2.4) it can be seen that χ ij and 𝑚𝑖𝑗 are symmetric. 3. third order shear deformation nanoplate model in fig.1 an isotropic rectangular nanoplate with length a, width b and thickness h is shown. figure 1. a schematic of the nanoplate and axes the displacement equations for the third order shear deformation nanoplate are defined as (according to the reddy shear theory): 𝑢1(𝑥, 𝑦, 𝑧, 𝑡) = 𝑧 𝜑𝑥 (𝑥, 𝑦, 𝑡) 4 3 ( 1 ℎ ) 2 𝑧3 ( 𝜕𝑤(𝑥,𝑦,𝑡) 𝜕𝑥 + 𝜑𝑥 (𝑥, 𝑦, 𝑡)) (3.1) 𝑢2(𝑥, 𝑦, 𝑧, 𝑡) = 𝑧𝜑𝑦 (𝑥, 𝑦, 𝑡) 4 3 ( 1 ℎ ) 2 𝑧3( 𝜕𝑤(𝑥,𝑦,𝑡) 𝜕𝑦 + 𝜑𝑦 (𝑥, 𝑦, 𝑡)) 𝑢3(𝑥, 𝑦, 𝑧, 𝑡) = 𝑤(𝑥, 𝑦, 𝑡) where φx and φy are rotation of the normal vector around the x, y and w are the displacement of the middle surface at the z axes. the symmetric part of curvature tensor, strain and stress tensor and rotation vector for third order shear deformation nanoplate model are as follows: ℇ𝑥𝑥 = 𝑧 𝜕𝜑𝑥 𝜕𝑥 − 4 3 ( 1 ℎ ) 2 𝑧3 ( 𝜕2𝑤 𝜕𝑥2 + 𝜕𝜑𝑥 𝜕𝑥 ) (3.2) ℇ𝑦𝑦 = 𝑧 𝜕𝜑𝑦 𝜕𝑦 − 4 3 ( 1 ℎ ) 2 𝑧3 ( 𝜕2𝑤 𝜕𝑦2 + 𝜕𝜑𝑦 𝜕𝑦 ) ℇ𝑧𝑧 = 0 ℇ𝑥𝑦 = ℇ𝑦𝑥 = 1 2 𝑧 ( 𝜕𝜑𝑥 𝜕𝑦 + 𝜕𝜑𝑦 𝜕𝑥 ) − 2 3 ( 1 ℎ ) 2 𝑧3 ( 𝜕𝜑𝑥 𝜕𝑦 + 𝜕𝜑𝑦 𝜕𝑥 + 2 𝜕2𝑤 𝜕𝑥𝜕𝑦 ) ℇ𝑥𝑧 = ℇ𝑧𝑥 = ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕𝑤 𝜕𝑥 + 𝜑𝑥 ) ℇ𝑦𝑧 = ℇ𝑧𝑦 = ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕𝑤 𝜕𝑦 + 𝜑𝑦 ) majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 171 𝜃𝑥 = 𝜕𝑤 𝜕𝑦 − ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕𝑤 𝜕𝑦 + 𝜑𝑦 ) (3.3) (3.4) (3.5) 𝜃𝑦 = − 𝜕𝑤 𝜕𝑥 + ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕𝑤 𝜕𝑥 + 𝜑𝑥 ) 𝜃𝑧 = 1 2 (𝑧 − 4 3 ( 1 ℎ ) 2 𝑧3) ( 𝜕 𝜑𝑦 𝜕𝑥 − 𝜕𝜑𝑥 𝜕𝑦 ) 𝑥𝑥𝑥 = 𝜕2𝑤 𝜕𝑥 𝜕𝑦 − ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕2𝑤 𝜕𝑥 𝜕𝑦 + 𝜕𝜑𝑦 𝜕𝑥 ) 𝑥𝑦𝑦 = − 𝜕2𝑤 𝜕𝑥𝜕𝑦 + ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕𝜑𝑥 𝜕𝑦 + 𝜕2𝑤 𝜕𝑥𝜕𝑦 ) 𝑥𝑧𝑧 = ( 1 2 − 2 ( 𝑧 ℎ ) 2 ) ( 𝜕𝜑𝑦 𝜕𝑥 − 𝜕𝜑𝑥 𝜕𝑦 ) 𝑥𝑥𝑦 = 1 2 ( 𝜕2𝑤 𝜕𝑦2 − 𝜕2𝑤 𝜕𝑥2 ) + ( 1 4 − ( 𝑧 ℎ ) 2 ) ( 𝜕2𝑤 𝜕𝑥2 + 𝜕𝜑𝑥 𝜕𝑥 − 𝜕2𝑤 𝜕𝑦2 − 𝜕𝜑𝑦 𝜕𝑦 ) 𝑥𝑥𝑧 = 1 4 (𝑧 − 4 3 ( 1 ℎ ) 2 𝑧3) ( 𝜕2𝜑𝑦 𝜕𝑥2 − 𝜕2𝜑𝑥 𝜕𝑦 𝜕𝑥 ) + 2𝑧 ( 1 ℎ ) 2 ( 𝜕𝑤 𝜕𝑦 + 𝜑𝑦 ) 𝑥𝑦𝑧 = −2𝑧 ( 1 ℎ ) 2 ( 𝜕𝑤 𝜕𝑥 + 𝜑𝑥 ) + 1 4 (𝑧 − 4 3 ( 1 ℎ ) 2 𝑧3) ( 𝜕2𝜑𝑦 𝜕𝑥𝜕𝑦 − 𝜕2𝜑𝑥 𝜕𝑦2 ) 𝜎𝑥𝑥 = (𝜆 + 2𝜇)ℇ𝑥𝑥 + 𝜆ℇ𝑦𝑦 𝜎𝑦𝑦 = 𝜆ℇ𝑥𝑥 + (𝜆 + 2𝜇)ℇ𝑦𝑦 𝜎𝑧𝑧 = 𝜆(ℇ𝑥𝑥 + ℇ𝑦𝑦 ) 𝜎𝑦𝑥 = 𝜎𝑥𝑦 = 2𝜇 ℇ𝑥𝑦 𝜎𝑥𝑧 = 𝜎𝑧𝑥 = 2𝜇 ℇ𝑥𝑧 𝜎𝑦𝑧 = 𝜎𝑧𝑦 = 2𝜇 ℇ𝑦𝑧 the variation of strain energy is expressed as: 𝛿𝑈 = ∫(𝜎𝑥𝑥 𝛿 ℇ𝑥𝑥 + 𝜎𝑦𝑦 𝛿ℇ𝑦𝑦 + 2𝜎𝑥𝑦 𝛿 ℇ𝑥𝑦 + 𝑣 2𝜎𝑥𝑧 𝛿 ℇ𝑥𝑧 + 2𝜎𝑦𝑧 𝛿 ℇ𝑦𝑧 + 𝑚𝑥𝑥 𝛿 𝑥𝑥𝑥 + 𝑚𝑦𝑦 𝛿𝑥𝑦𝑦 + 𝑚𝑧𝑧 𝛿𝑥𝑧𝑧 (3.6) +2𝑚𝑥𝑦 𝛿𝑥𝑥𝑦 + 2𝑚𝑥𝑧 𝛿𝑥𝑥𝑧 + 2𝑚𝑦𝑧 𝛿 𝑥𝑦𝑧 )𝑑𝑉 after substituting and simplify result in eq. (3.7): 𝛿𝑈 = ∫ 𝑉 (𝐸1𝛿𝑤,𝑥𝑥 + 𝐸2 𝛿𝑤,𝑦𝑦 + 𝐸3 𝛿𝑤,𝑥𝑦 + 𝐸4𝛿 𝑤,𝑥 +𝐸5 𝛿 𝑤,𝑦 + 𝐸6 𝛿 𝜑𝑥,𝑦𝑦 + 𝐸7𝛿 𝜑𝑦,𝑥𝑥 + 𝐸8 𝛿 𝜑𝑦,𝑥𝑦 + 𝐸9 𝛿𝜑𝑥,𝑦𝑥 +𝐸10 𝛿 𝜑𝑥,𝑥 + 𝐸11 𝛿𝜑𝑦,𝑦 + 𝐸12𝛿𝜑𝑥,𝑦 + 𝐸13 𝛿 𝜑𝑦,𝑥 + 𝐸14 𝛿𝜑𝑥 +𝐸15 𝛿𝜑𝑦 )𝑑𝑉 (3.7) the coefficients of variables ei are obtain in the appendix a. 𝐼𝑖 = ∫ 𝑍 𝑖 𝑑𝑧 ℎ 2 − ℎ 2 (𝑖 = 0,1, 2, 𝑛 − 1, 𝑛, 𝑛 + 1, 2𝑛 − 4, 2𝑛 − 2, 2𝑛) (3.8) 4. buckling load for a rectangular plate with length a, width b and thickness h with the forces 𝑃𝑥 , 𝑃𝑦 , 𝑃𝑥𝑦 and external force 𝑞(𝑥, 𝑦) the buckling force equation can be written as [7, 8]: 𝑃𝑥 𝜕2𝑤 𝜕𝑥2 + 2𝑃𝑥𝑦 𝜕2𝑤 𝜕𝑥𝜕𝑦 + 𝑃𝑦 𝜕2𝑤 𝜕𝑦2 = 𝑞(𝑥, 𝑦) (4.1) 5. virtual work of the external forces in this kind of problems, the virtual work of three kinds of external forces are included in the solutions, if the middle-plane and the middle-perimeter of the plate are shown as ω and γ respectively, these virtual works are [9]: 1. the virtual work done by the body forces, which is applied on the volume v= ω× (h⁄2, h⁄2). 2. the virtual work done by the surface tractions at the upper and lower surfaces (ω). 3. the virtual work done by the shear tractions on the lateral surfaces, s= γ× (h⁄2, h⁄2). if (fx, fy, fz) are the body forces, (cx, cy, cz) are the body couples, (qx, qy, qz) are the forces acting on the ω plane, (tx, ty, tz) are the cauchy's tractions and (sx, sy, sz) are surface couples the variation of the virtual work is expressed as: δw = − [∫ ω (fxδu + fyδv + fzδw + qxδu + qyδv + qzδw + cxδθx + cy δθy + czδθz) dx dy + ∫ γ (txδu + tyδv + tzδw + sxθx + syδθy + szδθz)dγ] (5.1) 172 majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 given that only external force qz is applied in this research, virtual work is as follows: 𝛿𝑤 = ∫ ∫ 𝑞(𝑥, 𝑦)𝛿𝑤(𝑥, 𝑦)𝑑𝑥 𝑑𝑦 𝑏 0 𝑎 0 (5.2) the kinetic energy variation is expressed as follows: 𝛿𝑇 = ∫ ∫ 𝜌(�̇�1𝛿�̇�1 + �̇�2𝛿�̇�2 + �̇�3𝛿�̇�3)𝑑𝐴 𝑑𝑧 ℎ 2 − ℎ 2 𝐴 (5.3) where ρ is density. in this study, the equation of motion is derived by hamilton’s principle. this principle can be expressed as [10]: ∫ (𝛿𝑇 − (𝛿𝑈 − 𝛿𝑤))𝑑𝑡 𝑇 0 = 0 (5.4) in which t is the kinetic energy, u is the strain energy and w is the work of external forces. 6. the final equation of the nanoplate by applying buckling and external force by applying the hamilton’s principle, the main equations are obtained as follows: [∫ ( 𝜕2𝐸1 𝜕𝑥2 − 𝜕𝐸4 𝜕𝑥 + 𝜕2𝐸2 𝜕𝑦2 + 𝜕2𝐸3 𝜕𝑥𝜕𝑦 − 𝜕𝐸5 𝜕𝑦 ) 𝑑𝑧 ℎ 2⁄ −ℎ 2⁄ ] + 𝑃𝑥 𝜕2𝑤 𝜕𝑥2 + 2𝑃𝑥𝑦 𝜕2𝑤 𝜕𝑥𝜕𝑦 +𝑃𝑦 𝜕2𝑤 𝜕𝑦2 = 𝑞(𝑥, 𝑦) + 𝜌𝐼0𝑤,𝑡𝑡 − 𝐶6 2 𝜌𝐼6 ( 𝜕2𝑤 𝜕𝑥2 + 𝜕2𝑤 𝜕𝑦2 ) ,𝑡𝑡 + 𝐶6 𝜌 𝐽4 ( 𝜕𝜑𝑥 𝜕𝑥 + 𝜕𝜑𝑦 𝜕𝑦 ) ,𝑡𝑡 ∫ ( 𝜕2𝐸6 𝜕𝑦2 + 𝜕2𝐸9 𝜕𝑥𝜕𝑦 − 𝜕𝐸12 𝜕𝑦 − 𝜕𝐸10 𝜕𝑥 + 𝐹14) 𝑑𝑧 = ℎ 2⁄ −ℎ 2⁄ 𝜌𝐾2𝜑𝑥,𝑡𝑡 − 𝐶6 𝜌𝐽4 ( 𝜕𝑤 𝜕𝑥 ) ,𝑡𝑡 (6.1) ∫ ( 𝜕2𝐸7 𝜕𝑥 2 − 𝜕𝐸13 𝜕𝑥 + 𝜕2𝐸8 𝜕𝑥𝜕𝑦 − 𝜕𝐸11 𝜕𝑦 + 𝐸15) 𝑑𝑧 ℎ 2⁄ −ℎ 2⁄ = 𝜌𝐾2𝜑𝑦,𝑡𝑡 − 𝐶6 𝜌𝐽4 ( 𝜕𝑤 𝜕𝑦 ) ,𝑡𝑡 𝐽4 = 𝐼4 − 𝐶6 𝐼6 𝐾2 = 𝐼2 − 2𝐶6 𝐼4 − 𝐶6 2 𝐼6 (6.2) 7. obtaining third order shear deformation nanoplate equations in the general state (including bending, buckling and vibrations) the general equations of the third order shear deformation nanoplate will be obtained as follows: the coefficients of variables from di are obtained in the appendix b. 𝐷1 𝜕4𝑤 𝜕𝑥2 𝜕𝑦2 + 𝐷2 𝜕4𝑤 𝜕𝑥4 + 𝐷2 𝜕4𝑤 𝜕𝑦4 + 𝐷3 𝜕2𝑤 𝜕𝑥2 + 𝐷3 𝜕2𝑤 𝜕𝑦2 + 𝐷4 𝜕3𝜑𝑥 𝜕𝑥3 + 𝐷4 𝜕3𝜑𝑥 𝜕𝑥 𝜕𝑦2 + 𝐷4 𝜕3𝜑𝑦 𝜕𝑦 𝜕𝑥2 + 𝐷3 𝜕𝜑𝑥 𝜕𝑥 + 𝐷3 𝜕𝜑𝑦 𝜕𝑦 + 𝐷4 𝜕3𝜑𝑦 𝜕𝑦3 + 𝑃𝑥 𝜕2𝑤 𝜕𝑥2 + 2𝑃𝑥𝑦 𝜕2𝑤 𝜕𝑥𝜕𝑦 +𝑃𝑦 𝜕2𝑤 𝜕𝑦2 = 𝑞(𝑥, 𝑦) + 𝜌ℎ 𝜕2𝑤 𝜕𝑡2 − 𝐷11 ( 𝜕4𝑤 𝜕𝑥2 𝜕𝑡2 + 𝜕4𝑤 𝜕𝑦2 𝜕𝑡2 ) + 𝐷12 ( 𝜕3𝜑𝑥 𝜕𝑥 𝜕𝑡2 + 𝜕3𝜑𝑦 𝜕𝑦 𝜕𝑡2 ) (7.1) −𝐷4 𝜕3𝑤 𝜕𝑥 𝜕𝑦2 + 𝐷5 𝜕2𝜑𝑦 𝜕𝑦 𝜕𝑥 + 𝐷6 𝜕2𝜑𝑥 𝜕𝑦2 + 𝐷7 𝜕4𝜑𝑦 𝜕𝑥 𝜕𝑦3 − 𝐷7 𝜕4𝜑𝑥 𝜕𝑦4 + 𝐷7 𝜕4𝜑𝑦 𝜕𝑦 𝜕𝑥3 − 𝐷7 𝜕4𝜑𝑥 𝜕𝑦2 𝜕𝑥2 − 𝐷3 𝜕𝑤 𝜕𝑥 − 𝐷3𝜑𝑥 − 𝐷4 𝜕3𝑤 𝜕𝑥3 + 𝐷8 𝜕2𝜑𝑥 𝜕𝑥2 = −𝐷12 𝜕3𝑤 𝜕𝑥 𝜕𝑡2 + 𝐷13 𝜕2𝜑𝑥 𝜕𝑡2 (7.2) −𝐷4 𝜕3𝑤 𝜕𝑦 𝜕𝑥2 + 𝐷9 𝜕2𝜑𝑥 𝜕𝑦 𝜕𝑥 + 𝐷10 𝜕2𝜑𝑦 𝜕𝑥2 + 𝐷7 𝜕4𝜑𝑦 𝜕𝑥4 + 𝐷7 𝜕4𝜑𝑦 𝜕𝑥2 𝜕𝑦2 − 𝐷7 𝜕4𝜑𝑥 𝜕𝑦 𝜕𝑥3 − 𝐷7 𝜕4𝜑𝑥 𝜕𝑥 𝜕𝑦3 − 𝐷4 𝜕3𝑤 𝜕𝑦3 − 𝐷3 𝜕𝑤 𝜕𝑦 − 𝐷3𝜑𝑦 + 𝐷8 𝜕2𝜑𝑦 𝜕𝑦2 = −𝐷12 𝜕3𝑤 𝜕𝑦 𝜕𝑡2 + 𝐷13 𝜕2𝜑𝑦 𝜕𝑡2 (7.3) 8. navier solution method the navier solution method is applicable to rectangular plates with simply supported boundary conditions on all edges. the displacement functions of the middle surface can be expanded in the forms of double trigonometric series as follows [9, 11]: 𝑊(𝑥, 𝑦, 𝑡) = ∑ ∑ 𝑊𝑚𝑛 𝑠𝑖𝑛 𝛼𝑥 𝑠𝑖𝑛 𝛽𝑦 𝑒 𝑖𝜔𝑡 ∞ 𝑛=1 ∞ 𝑚=1 (8.1) 𝜑𝑥 (𝑥, 𝑦, 𝑡) = ∑ ∑ 𝑋𝑚𝑛 𝑐𝑜𝑠 𝛼𝑥 𝑠𝑖𝑛 𝛽𝑦 𝑒 𝑖𝜔𝑡 ∞ 𝑛=1 ∞ 𝑚=1 𝜑𝑦 (𝑥, 𝑦, 𝑡) = ∑ ∑ 𝑦𝑚𝑛 𝑠𝑖𝑛 𝛼𝑥 𝑐𝑜𝑠 𝛽𝑦 𝑒 𝑖𝜔𝑡 ∞ 𝑛=1 ∞ 𝑚=1 load can also be calculated from the following equation: 𝑞 = ∑ ∑ 𝑄𝑚𝑛 𝑠𝑖𝑛 𝛼𝑥 𝑠𝑖𝑛 𝛽𝑦 𝑒 𝑖𝜔𝑡 ∞ 𝑛=1 ∞ 𝑚=1 (8.2) 𝑄𝑚𝑛 = 4𝑎𝑏 ∫ ∫ 𝑞(𝑥, 𝑦)𝑠𝑖𝑛𝛼𝑥 𝑠𝑖𝑛 𝛽𝑦 𝑑𝑥 𝑑𝑦 𝑏 0 𝑎 0 where 𝛼 = 𝜋𝑚 𝑎 , 𝛽 = 𝜋𝑛 𝑏 , 𝑖 = √−1 majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 173 9. obtaining the matrix of third order shear deformation nanoplate equations after solving the equation using the navier method the general matrix of third order shear deformation nanoplate equations will be obtained as follows: ([ 𝑅1 𝑅2 𝑅3 𝑅4 𝑅5 𝑅6 𝑅7 𝑅8 𝑅9 ] − 𝜔2 [ 𝐺1 𝐺2 𝐺3 𝐺4 𝐺5 𝐺6 𝐺7 𝐺8 𝐺9 ]) [ 𝑤𝑚𝑛 𝑋𝑚𝑛 𝑦𝑚𝑛 ] = [ 𝑄𝑚𝑛 0 0 ] (9.1) the coefficients of variables ri and gi are obtained in the appendix c. in this paper, graphene is considered for the material of the nanoplate. a single layer graphene sheet has the following properties [10]: 𝖤 = 1.06𝑇𝑃𝑎, 𝜈 = 0.25 , ℎ = 0.34𝑛𝑚, 𝜌 = 2250 𝑘𝑔 𝑚3 ⁄ also, the relationship between e, μ and ν can be written as: 𝜆 = 𝜈𝘌 (1 + 𝜈)(1 − 2𝜈) , 𝜇 = 𝘌 2(1 + 𝜈) where e is the young modulus and μ and λ are lame coefficients [12]. also, q = 1n / m2. 10. results and discussion the results are obtained using matlab software. all boundary conditions are also considered as simply supported. table 1 compares the dimensionless static deflections of nanoplates subjected to a sinusoidal load. according to the table 1, the dimensionless static deflections of kirchhoff nanoplate has the highest value and the mindlin nanoplate has the lowest. table 2 compares the dimensionless static deflections of the third order shear deformation nanoplate subjected to the uniform load for different value of length/width ratio. it is observed that except classical mode (l =0), by increasing the length scales parameter/thickness ratio, the dimensionless static deflections is decreased. also by increasing the length/width ratio, it is increased. table 1. comparison of dimensionless static deflections of nanoplates subjected to a sinusoidal load for different values of a/b (a / h = 30, q = 1e-18n / nm2, l / h = 1). a/b kirchhoff plate mindlin plate third order shear deformation plate n order shear deformation plate (n=5) 1.0 0.2 0.07226 0.19912 0.19907 1.5 0.2 0.07212 0.19927 0.19923 2.0 0.2 0.07204 0.19935 0.19931 table 2. dimensionless static deflections of the third order shear deformation nanoplate subjected to the uniform load for different value of length/width ratio (q = 1e-18 n / nm2 a / h = 30) a/b l/h 0.0 0.5 1.0 2.0 1.0 1.00000 0.49874 0.19922 0.05856 1.5 1.00000 0.49911 0.19945 0.05864 2.0 1.00000 0.49923 0.19952 0.05866 table 3 compares the static deflections of the third order shear deformation nanoplate subjected to the sinusoidal load for different values of length/width ratio. it is observed that by increasing the length scales parameter/thickness ratio, the static deflections is decreased. also by increasing the length/width ratio, it is increased. table 3. static deflections of the third order shear deformation nanoplate subjected to the sinusoidal load for different values of length/width ratio (q = 1e-18 n / nm ^ 2 a / h = 30) a/b l/h 0.0 0.5 1.0 2.0 1.0 07.0630 03.5215 1.4064 0.4134 1.5 14.2905 07.1284 2.8477 0.8371 2.0 21.1039 10.5297 4.2070 1.2367 figure 2 shows the dimensionless critical buckling load of the third order shear deformation nanoplate for biaxial buckling and different value of length/thickness ratio. it is observed that by increasing the length scales parameter/thickness ratio the dimensionless critical buckling load is increased. also except for the classical mode (l = 0) by increasing the length/ thickness ratio, it is decreased. dimensionless critical buckling load for uniaxial buckling and different nanoplate dimensionless critical buckling load for uniaxial buckling and different nanoplate. figure 2. comparison of the dimensionless critical buckling load of the third order shear deformation nanoplate for biaxial buckling and different values of length/thickness ratio (a / b = 1) table 4 compares the dimensionless critical buckling load for uniaxial buckling and different nanoplate. according to table 4: • by increasing the length/thickness ratio of the mindlin nanoplate, the dimensionless critical buckling load for uniaxial buckling is increased. • by increasing the length/thickness ratio of the third and fifth order shear deformation nanoplates, the dimensionless critical buckling load for uniaxial buckling is slightly decreased. • by increasing the length/thickness ratio of the kirchhoff nanoplate, the dimensionless critical buckling load for uniaxial buckling is fixed. 174 majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 table 4. dimensionless critical buckling load for uniaxial buckling and different nanoplates (a / b = 1, l / h = 1) a/h kirchhoff nanoplate mindlin nanoplate third order shear deformation nanoplate n order shear deformation nanoplate (n=5) 05 5.0000 10.1594 5.6521 5.6937 10 5.0000 12.8100 5.1723 5.1826 20 5.0000 13.6820 5.0437 5.0463 30 5.0000 13.8568 5.0195 5.0206 40 5.0000 13.9191 5.0110 5.0116 50 5.0000 13.9481 5.0070 5.0074 figure 3 shows the critical buckling load of the third order shear deformation nanoplate for uniaxial buckling and different value of length/thickness ratio. it is observed that by increasing the length scales parameter/thickness ratio the critical buckling load is increased. also, by increasing the length/ thickness ratio, it is decreased. figure 3. comparison of the critical buckling load of the third order shear deformation nanoplate for uniaxial buckling and different values of length/thickness ratio (a / b = 1) table 5. shows the dimensionless critical buckling load of the third order shear deformation nanoplate for biaxial buckling and different buckling modes. it is observed that by increasing the length scales parameter/thickness ratio the dimensionless critical buckling load is increased. also, for first mode, it is minimum. table 5. comparison of the dimensionless critical buckling load of the third order shear deformation nanoplate for biaxial buckling and different buckling modes (a/h = 30 and a/b = 1) mode l/h 0.0 0.5 1.0 2.0 𝑝11 1.0000 2.0050 5.0195 17.0765 𝑝12 1.0000 2.0125 5.0486 17.1908 𝑝21 1.0000 2.0125 5.0486 17.1908 𝑝22 1.0000 2.0199 5.0774 17.3044 figures 4 to 7 show the dimensionless frequencies (ω11 / ω𝑐𝑡 ω12 / ω𝑐𝑡 ω21 / ω𝑐𝑡 ω22 / ω𝑐𝑡 ) of the third order shear deformation nanoplate for different values of length/thickness ratio. it is observed that by increasing the length scales parameter/thickness ratio, the dimensionless frequencies are increased. also except for classical mode (l = 0) by increasing the length/ thickness ratio, it is decreased. as well as for first mode, it is minimum. figure. 4. comparison of the dimensionless frequencies (𝛚𝟏𝟏) of the third order shear deformation nanoplate for different values of length/thickness ratio (a / b = 1, h = 0.34) figure 5. comparison of the dimensionless frequencies (𝛚𝟏𝟐) of the third order shear deformation nanoplate for different values of length/thickness ratio (a / b = 1, h = 0.34) figure 6. comparison of the dimensionless frequencies (𝛚𝟐𝟏) of the third order shear deformation nanoplate for different values of length/thickness ratio (a / b = 1, h = 0.34) majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 175 figure 7. comparison of the dimensionless frequencies (𝛚𝟐𝟐) of the third order shear deformation nanoplate for different values of length/thickness ratio (a / b = 1, h = 0.34) table 6. comparison of the frequencies of the third order shear deformation nanoplate for different value of length scales parameter /thickness ratio (mhz) (a / b = 1, a / h = 30) mode l/h 0 0.5 1 2 𝜔11 13.9441 19.7447 31.2407 57.6223 𝜔12 34.6497 49.1546 77.8533 143.6613 𝜔21 34.6497 49.1546 77.8533 143.6613 𝜔22 55.1098 78.3225 124.1752 229.2384 𝜔33 121.6342 173.8911 276.5826 511.3107 table 7. comparison of frequencies for the different nanoplates (a / b = 0.5, l / h = 1) mode a/h 20 30 40 mindlin plate 𝜔11 280.4153 128.0217 72.7219 𝜔21 436.5378 202.1703 115.4757 𝜔12 860.2980 413.9252 240.0504 𝜔22 988.5087 481.2484 280.4153 kirchhoff plate 𝜔11 175.2090 78.0917 43.9704 𝜔21 279.4825 124.7767 70.2985 𝜔12 588.5668 264.0744 149.0415 𝜔22 690.3772 310.2573 175.2090 third order shear deformation plate 𝜔11 174.0385 77.8533 43.8941 𝜔12 276.5826 124.1752 70.1049 𝜔21 576.6542 261.4753 148.1887 𝜔22 674.3836 306.7113 174.0385 table 6 shows that by increasing the length scales parameter/thickness ratio, the frequencies of different modes (ω11-ω12-ω21-ω22) are increased. table 7. shows the frequency of different modes (ω11-ω12-ω21-ω22) for different nanoplates. according to the table, the frequency of mindlin nanoplate is maximum and for third order shear deformation 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[22] banh-thien, t., dang-trung, h., le-anh, l., ho-huu, v., & nguyen-thoi, t., buckling analysis of non-uniform thickness nanoplates in an elastic medium using the isogeometric analysis. composite structures, vol.162, pp.182-193, (2017 ). appendix. a 𝐸1 = 𝜕2𝑤 𝜕𝑥2 [ (𝜆 + 2𝜇)(𝐶3 − 𝐶1𝐶2) + 1 2 𝜇𝑙2(1 + 𝐶4) − 1 4 𝜇𝑙2(1 + 𝐶4)(1 − 𝐶4)] + 𝜕2𝑤 𝜕𝑦2 [𝜆(𝐶3 − 𝐶1𝐶2) − 1 2 𝜇𝑙2(1 + 𝐶4) + 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑥 𝜕𝑥 [−(𝜆 + 2𝜇)(𝐶2𝐶1) − 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑦 𝜕𝑦 [−𝜆(𝐶2𝐶1) − 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] (a-1) 𝐸2 = 𝜕2𝑤 𝜕𝑦2 [ (𝜆 + 2𝜇)(𝐶3 − 𝐶1𝐶2) + 1 2 𝜇𝑙2(1 + 𝐶4) − 1 4 𝜇𝑙2(1 + 𝐶4)(1 − 𝐶4 )] + 𝜕2𝑤 𝜕𝑥2 [𝜆(𝐶3 − 𝐶1𝐶2) − 1 2 𝜇𝑙2(1 + 𝐶4) + 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑦 𝜕𝑦 [−(𝜆 + 2𝜇)(𝐶2𝐶1) − 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑥 𝜕𝑥 [−𝜆(𝐶2𝐶1) − 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] (a-2) 𝐸3 = 𝜕2𝑤 𝜕𝑥 𝜕𝑦 [4𝜇 𝐶2 2 + 𝜇𝑙2(1 + 𝐶4) 2] + 𝜕𝜑𝑥 𝜕𝑦 [−2𝜇𝐶2𝐶1 − 1 2 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑦 𝜕𝑥 [−2𝜇𝐶2𝐶1 − 1 2 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] (a-3) 𝐸4 = ( 𝜕𝑤 𝜕𝑥 + 𝜑𝑥 ) [𝜇(1 − 𝐶4) 2 + 1 4 𝜇𝑙2𝐶5 2 ] + ( 𝜕2𝜑𝑦 𝜕𝑥𝜕𝑦 − 𝜕2𝜑𝑥 𝜕𝑦2 ) [ 1 4 𝜇𝑙2𝐶5𝐶1] (a-4) 𝐸5 = ( 𝜕𝑤 𝜕𝑦 + 𝜑𝑦 ) [𝜇(1 − 𝐶4) 2 + 1 4 𝜇𝑙2𝐶5 2 ] + ( 𝜕2𝜑𝑥 𝜕𝑥𝜕𝑦 − 𝜕2𝜑𝑦 𝜕𝑥 2 ) [ 1 4 𝜇𝑙2𝐶5𝐶1] (a-5) 𝐸6 = 𝐸8 = ( 𝜕𝑤 𝜕𝑥 + 𝜑𝑥 ) [ 1 4 𝜇𝑙2𝐶5𝐶1] + ( 𝜕2𝜑𝑦 𝜕𝑥𝜕𝑦 − 𝜕2𝜑𝑥 𝜕𝑦2 ) [ 1 4 𝜇𝑙2𝐶1 2 ] (a-6) 𝐸7 = 𝐸9 = ( 𝜕𝑤 𝜕𝑦 + 𝜑𝑦 ) [− 1 4 𝜇𝑙2𝐶5𝐶1] + ( 𝜕2𝜑𝑦 𝜕𝑥2 − 𝜕2𝜑𝑥 𝜕𝑥𝜕𝑦 ) [ 1 4 𝜇𝑙2𝐶1 2 ] (a-7) 𝐸10 = 𝜕2𝑤 𝜕𝑥2 [ (𝜆 + 2𝜇)(𝐶1 2 − 𝑧𝐶1) − 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕2𝑤 𝜕𝑦2 [𝜆𝐶1(−𝑧 + 𝐶1) + 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑥 𝜕𝑥 [ (𝜆 + 2𝜇)𝐶1 2 + 1 4 𝜇𝑙2(1 − 𝐶4) 2] + 𝜕𝜑𝑦 𝜕𝑦 [𝜆𝐶1 2 − 1 4 𝜇𝑙2(1 − 𝐶4) 2] (a-8) 𝐸11 = 𝜕2𝑤 𝜕𝑦2 [ (𝜆 + 2𝜇)(𝐶1 2 − 𝑧𝐶1) − 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕2𝑤 𝜕𝑥2 [𝜆𝐴1(−𝑧 + 𝐶1) + 1 4 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑦 𝜕𝑦 [ (𝜆 + 2𝜇)𝐶1 2 + 1 4 𝜇𝑙2(1 − 𝐶4) 2] + 𝜕𝜑𝑥 𝜕𝑥 [𝜆𝐶1 2 − 1 4 𝜇𝑙2(1 − 𝐶4) 2] (a-9) 𝐸12 = 𝜕2𝑤 𝜕𝑥 𝜕𝑦 [−2𝜇𝐶2𝐶1 − 1 2 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑥 𝜕𝑦 [𝜇𝐶1 2 + 𝜇𝑙2(1 − 𝐶4) 2] + 𝜕𝜑𝑦 𝜕𝑥 [𝜇𝐶1 2 − 1 2 𝜇𝑙2(1 − 𝐶4) 2] (a-10) 𝐸13 = 𝜕2𝑤 𝜕𝑥 𝜕𝑦 [−2𝜇𝐶2𝐶1 − 1 2 𝜇𝑙2(1 − 𝐶4)(1 + 𝐶4)] + 𝜕𝜑𝑥 𝜕𝑦 [𝜇𝐶1 2 − 1 2 𝜇𝑙2(1 − 𝐶4) 2] + 𝜕𝜑𝑦 𝜕𝑥 [𝜇𝐶1 2 + 𝜇𝑙2(1 − 𝐶4) 2] (a-11) 𝐸14 = ( 𝜕𝑤 𝜕𝑥 + 𝜑𝑥 ) [𝜇(1 − 𝐶4) 2 + 1 4 𝜇𝑙2𝐶5 2 ] + ( 𝜕2𝜑𝑦 𝜕𝑥𝜕𝑦 − 𝜕2𝜑𝑥 𝜕𝑦2 ) [ 1 4 𝜇𝑙2𝐶5𝐶1] (a-12) 𝐸15 = ( 𝜕𝑤 𝜕𝑦 + 𝜑𝑦 ) [𝜇(1 − 𝐶4) 2 + 1 4 𝜇𝑙2𝐶5 2 ] + ( 𝜕2𝜑𝑥 𝜕𝑥𝜕𝑦 − 𝜕2𝜑𝑦 𝜕𝑥 2 ) [ 1 4 𝜇𝑙2𝐶5𝐶1] (a-13) https://www.sciencedirect.com/science/journal/aip/02638223 majid eskandari shahraki et al. /al-qadisiyah journal for engineering sciences 14 (2022) 169–177 177 where: 𝐶1 = 𝑧 − 4 3 ( 1 ℎ ) 2 𝑧3 (a-14) 𝐶2 = 4 3 ( 1 ℎ ) 2 𝑧3 (a-15) 𝐶3 = 4 3 ( 1 ℎ ) 2 𝑧4 (a-16) 𝐶4 = 4 ( 𝑧 ℎ ) 2 (a-17) 𝐶5 = −8𝑧 ( 1 ℎ ) 2 (a-18) 𝐶6 = 4 3 ( 1 ℎ ) 2 (a-19) 𝐶7 = 𝜇 ℎ 3 (a-20) 𝐶8 = 𝜇 ℎ 5 (a-21) 𝐶9 = ℎ3 252 (𝜆 + 2𝜇) (a-22) 𝐶10 = (𝜆 + 2𝜇) ℎ3 60 (a-23) 𝐶11 = 𝜇 𝑙 2 4 3ℎ (a-24) 𝐶12 = 1 4 𝜇 𝑙2ℎ (a-25) appendix. b 𝐷1 = 2𝐶12 + 𝑙 2𝐶7 + 1 2 𝑙2𝐶8 + 2𝐶9 (b-1) 𝐷2 = 1 2 𝐷1 = 𝐶12 + 𝐶9 + 1 2 𝑙2𝐶7 + 1 4 𝑙2𝐶8 (b-2) 𝐷3 = −𝜇ℎ + 2𝐶7 − 𝐶8 − 𝐶11 (b-3) 𝐷4 = 𝐶9 − 𝐶10 + 1 4 𝑙2𝐶8 − 𝐶12 (b-4) 𝐷5 = 3𝐶12 − 3 2 𝑙2𝐶7 + 3 4 𝑙2𝐶8 − (𝜆 + 𝜇)𝐼2 + 2(𝜆 + 𝜇)𝐶6 𝐼4 − (𝜆 + 𝜇)𝐶6 2 𝐼6 (b-5) 𝐷6 = −𝜇𝐼2 + 2𝜇𝐶6 𝐼4 − 𝜇𝐶6 2 𝐼6 − 4𝐶12 + 2𝑙 2𝐶7 − 𝑙 2𝐶8 (b-6) 𝐷7 = 1 4 𝜇𝑙2𝐼2 − 1 2 𝜇𝑙2𝐶6𝐼4 + 1 4 𝜇𝑙2𝐶6 2 𝐼6 (b-7) 𝐷8 = −(𝜆 + 2𝜇)𝐼2 + 2𝐶10 − 𝐶9 − 𝐶12 + 1 2 𝑙2𝐶7 − 1 4 𝑙2𝐶8 (b-8) 𝐷9 = 5 4 𝑙2𝐶8 − 3 2 𝜇𝑙2𝐶6 2 𝐼4 − 5 2 𝑙2𝐶7 + 3𝐶12 − (𝜆 + 𝜇)𝐼2 − (𝜆 + 𝜇)𝐶6 2 𝐼6 + 2(𝜆 + 𝜇)𝐶6𝐼4 (b-9) 𝐷10 = 3𝑙 2𝐶7 − 3 2 𝑙2𝐶8 + 3 2 𝜇𝑙2𝐶6 2 𝐼4 − 𝜇𝐼2 − 𝜇𝐶6 2 𝐼6 + 2𝜇𝐶6𝐼4 − 4𝐶12 (b-10) 𝐷11 = 𝜌𝐶6 2 𝐼6 (b-11) 𝐷12 = 𝜌𝐶6𝐼4 − 𝜌𝐶6 2 𝐼6 (b-12) 𝐷13 = 𝜌𝐼2 − 2𝜌𝐶6𝐼4 − 𝜌𝐶6 2 𝐼6 (b-13) appendix. c 𝑅1 = 𝐷1𝛼 2𝛽2 + 𝐷2𝛼 4 + 𝐷2𝛽 4 − 𝐷3𝛼 2 − 𝐷3𝛽 2 − 𝑃𝑥 𝛼 2 − 𝑃𝑦 𝛽 2 (c-1) 𝑅2 = 𝑅4 = 𝐷4𝛼 3 + 𝐷4𝛼 𝛽 2 − 𝐷3𝛼 (c-2) 𝑅3 = 𝑅7 = 𝐷4𝛽 3 + 𝐷4𝛼 2𝛽 − 𝐷3𝛽 (c-3) 𝑅5 = −𝐷7𝛽 4 − 𝐷7𝛼 2𝛽2 − 𝐷6𝛽 2 − 𝐷8𝛼 2 − 𝐷3 (c-4) 𝑅6 = 𝐷7𝛼𝛽 3 + 𝐷7𝛼 3𝛽 − 𝐷5𝛼𝛽 (c-5) 𝑅8 = −𝐷7𝛼 3𝛽 − 𝐷7𝛼𝛽 3 − 𝐷9𝛼𝛽 (c-6) 𝑅9 = 𝐷7 𝛼 4 + 𝐷7𝛼 2𝛽2 − 𝐷10𝛼 2 − 𝐷8𝛽 2 − 𝐷3 (c-7) 𝐺1 = −𝐷11𝛼 2 − 𝐷11 𝛽 2 − 𝜌ℎ (c-8) 𝐺2 = 𝐺4 = 𝐷12𝛼 (c-9) 𝐺3 = 𝐺7 = 𝐷12𝛽 (c-10) 𝐺5 = 𝐺9 = −𝐷13 (c-11) 𝐺6 = 𝐺8 = 0 (c-12) article al-qadisiyah journal for engineering sciences 15 (2022) 087–093 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: alimohjasim@gmail.com (ali m. jasim) https://doi.org/10.30772/qjes.v15i2.818 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. flexural and fatigue behaviour of natural fibrous reinforced polymeric composite materials ali m. jasim * and ibtihal a. mahmood department of mechanical engineering, university of technology, baghdad, iraq a r t i c l e i n f o article history: received 11 may 2022 received in revised form 17 june 2022 accepted 13 july 2022 keywords: composite materials endurance limit fatigue life blend natural fiber a b s t r a c t in this study, the mechanical properties, fatigue life, and endurance limit values were investigated for composite materials containing natural fiber reinforcement (flax, wool), which were arranged by 0°/90° angle orientation and a combination of 0°/90° and 45°/-45° angle orientation, then the wool woven mixed by flax woven and unidirectional flax interfered with jute woven. binary blends containing epoxy and polyurethane at v were mixed at various weight percent (0%, 5%, 10%, and 15 %) vacuum infusion technique was used to prepare the specimens. ansys workbench was used as numerical software to investigate the fatigue behavior and endurance limit values of the unreinforced and reinforced blend. it was found that the weight percentage of 10% polyurethane in the blends was the optimal percentage providing the best fatigue life and the endurance limit value, endurance limit values of wool composite improved when hybridized by flax woven and unidirectional flax interfered with jute woven by 132.895 % and 66.549 % respectively. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the composite material consists of two or more constituent materials insoluble in each other: the matrix (continuous phase) and the reinforcement [1]. the growth using synthetic materials in industry applications increased environmental problems because these materials are not environmentally friendly, natural fibers offered an alternative to replace synthetic fibers, and these bio-material fibers have great potential as reinforcements, which provide thermal stability, low cost, lower energy requirement, wide availability, excellent biodegradability and environmentally friendly [2, 3]. the fatigue phenomenon is the cause of most fractures in engineering parts during service with the presence of cyclic loads, the fracture occurs under withstanding loads, which are still within the elastic zone under the stressstrain curve. at service, fatigue failures are involved in at least 90% of all mechanical failures. for brittle materials, fatigue failures are particularly dangerous because they do not usually show signs of imminent failure, but this happens suddenly and without noticing the overall plastic deformations, which throughout history have caused important accidents with catastrophic consequences [4, 5]. abdullah, a. h., et al. investigated the tensile and fatigue behavior of epoxy reinforced with unidirectional kenaf. the results were compared with unreinforced epoxy, which showed that increasing the volume fraction of kenaf improved the fatigue life [6]. saeed, a. r was prepared composite materials with a polymer basis by the match and lay-up method posited materials were prepared from http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i2.818 https://doi.org/10.30772/qjes.v15i2.818 http://creativecommons.org/licenses/by/4.0/ 88 ali jasim and ibtihal mahmood /al-qadisiyah journal for engineering sciences 15 (2022) 087–093 unsaturated polyester resin as a base material supported with natural wool fibers, which were distributed randomly, with weight fractions (3%, 4%, and 5%). the results of the research showed that the value of the impact resistance and electrical insulation increased with increasing the weight of the wool fiber [7]. bensadoun, f., et al. investigated the fatigue behavior of composite material made by epoxy reinforced with five architectures textile fabric of the flax, which are random mat, plain weave, twill, quasiunidirectional, and unidirectional with a volume fraction of 40%, except 30% for the mat. the result showed that the fatigue behavior was affected by changing the type of architectures flax fabric type, minimum fatigue life for the random mat fabric, the fatigue life was increased for plain weave and twill fabric, and the highest at using the quasiunidirectional fabric [8]. hojo, t., et al. fabricated and tested polymeric composite containing several types of a mat natural fiber, which included unidirectional jute, unidirectional kenaf, and unidirectional bamboo, unsaturated polyester was used as a matrix. the test included tensile and low cycle fatigue. the results were compared with a unidirectional glass mat. the result showed that natural fibers show good properties as reinforcement into composites compared with glass fiber and show a potential replacement with some types of synthetic fiber [9]. asgarinia, s., et al. investigated the fatigue the behavior of composites material made by epoxy reinforced with flax (f) as natural fiber woven and e-glass (g) as synthetic woven, the vacuum infusion was used to fabricate the samples several cyclesstress to failure (s-n) of all hybrid configurations were obtained. by comparison between flax and glass hybrid, the flax composites have good fatigue behavior, which shows a potential implementation in bearing applications [10]. 2 experimental works 2.1. matrix material the epoxies polymerase has good mechanical properties, but they have low break deformation, low crack propagation resistance, and is brittle. in contrast, the polyurethane polymer has low mechanical properties, flexible and elastic. depending on the mixing weight percentages ratio between epoxy and polyurethane, epoxies' disadvantages can be reduced. the blend is prepared by mixing the epoxy (ep) and the polyurethane (pu) (at 0 %, 5 %, 10 %, and 15 % weight percentages), which are blended by the following steps (figure 1a): 1the epoxy and polyurethane resins were mixed by the requiring weight percentage. 2the epoxy and polyurethane hardeners were mixed by the required weight percentage. 3all the components of the resins and hardeners were mixed. 4a vacuum chamber was used to remove the bubbles from the components. 2.2. natural fiber reinforcements three types were woven (figure 1b) used to reinforce the matrix, which: are flax, wool, and unidirectional flax interfered with jute woven (jf). figure 1. preparation, (a) mixing blend, (b) natural fiber reinforcements 2.3. fabrication of composite materials the vacuum infusion technique was used to prepare the specimens, figure 2 shows the equipment used in the system, which is; a vacuum pump, vacuum chamber, trap, digital weighing scale, pressure gauge, and woven fibers stacked within a vacuum bag, this bag must be completely hermetic with its respective input and output blend pipelines, and then the vacuum pump was activated to extract the air and to check the leak. the pressure difference leads to infusion, which allows the blend to pass through the nomenclature: ep epoxy symbols pu polyurethane fa flax laminate arranged by 0°/90° angle orientation pu5 the blend contains 95% epoxy and 5% polyurethane fb flax laminate arranged by a combination of 0°/90° and 45°/45° angle orientation pu10 the blend contains 90% epoxy and 10% polyurethane wa wool laminate arranged by 0°/90° angle orientation pu15 the blend contains 85% epoxy and 15% polyurethane wb wool laminate arranged by a combination of 0°/90° and 45°/-45° angle orientation jf unidirectional flax interfered with jute woven hwaf hybrid contains wool and flax ali jasim and ibtihal mahmood /al-qadisiyah journal for engineering sciences 15 (2022) 087–093 89 woven fibers until saturation, then the inlet and outlet of blend tubes were closed, and the pump is turned off. the mold was kept for three days to cure at room temperature [11]. the wool layers are arranged by 0°/90° angle orientation (wa) and a combination of 0°/90° and 45°/-45° angle orientation (wb), also the flax layers are arranged by 0°/90° angle orientation (fa) and a combination of 0°/90° and 45°/-45° (fb). figure 2. vacuum infusion technique to improve the mechanical properties of wool, the woven wool (wa) was hybridized by two laminates at the top and two laminates at bottom of flax (hwaf), and the woven wool (wa) was hybridized by one layer of jf at the top and the other at the bottom (hwajf), as shown in figure 3. figure 3. hybrids composites 2.4. the mechanical properties flexural and fatigue life test was used to analyze the mechanical properties of the fabricated composite samples. bending test : three-point bending (flexural tests) was applied according to astm d790 (figure 4). the mechanical properties of the unreinforced and reinforced blend were measured. the bending tests were carried out using the universal machine tinius olsen h50kt with a maximum capacity of 50kn. the separation between supports was determined using a 16:1 spanto-thickness ratio [12]. the dimensions of the specimens were established by 125x10x4 mm (figure 5) and span length = 64 mm, the test speed was 2mm/min at room temperature. figure 4. bending testing machine figure 5. bending specimens figure 6. fatigue testing machine fatigue test : machine type hitech (hsm-20) with alternative bending stress was used to test the fatigue life at constant amplitude (figure 6). the specimens were fixed at one end, while the alternative bending stress was subjected to the other end. the dimensions of the specimens were established by 100x10x4 mm (figure 7). 90 ali jasim and ibtihal mahmood /al-qadisiyah journal for engineering sciences 15 (2022) 087–093 figure 7. fatigue specimens the stress value (σ), determined by the specimen deflection (𝛿𝑒) and the specimen's effective length (𝑙𝑒 ), which is calculated by applying the relation [13]. 𝜎 = 1.5𝐸𝑓 𝑡𝛿𝑒 𝑙𝑒 2 (1) where, 𝜎: is the alternative bending stress (mpa) 𝐸𝑓 : the flexural modulus (mpa) 𝑡 : is the thickness of the specimens (4 mm) 𝛿𝑒 : is the deflection of the specimen (mm) 𝑙𝑒 : is the specimen's effective length (mm) 3. numerical analysis ansys.19 workbench was used as numerical software to investigate the fatigue results of unreinforced and reinforced composite. in this work, hex dominant was used to carry out element type, the number of elements was 2400, and the number of nodes was12389, as shown in figure 8. the boundary conditions of the model applied are fixed support on the first side and the alternative load effect on the other side. the material properties were imported from the experimental results [14]. figure 8. the meshing of the specimens figure 9. numerical fatigue of the specimens 4. results and discussion 4.1. bending results figure 10 shows the stress-strain curves of the blend matrix which is mixed into the blend by (0%, 5%, 10%, and 15% pu). the samples were tested without natural fiber reinforcement and the results are shown in figure 11, which include the yield stress, ultimate stress, and maximum strain. figure 10. stress-strain curves of different composite materials figure 11. stress-strain curves result from different composite materials ali jasim and ibtihal mahmood /al-qadisiyah journal for engineering sciences 15 (2022) 087–093 91 compared with pure epoxy, mixing polyurethane with epoxy reduces the yield stress and ultimate stress while increasing the maximum strain. figures 12, 13, and 14 show the stress-strain curves of wool woven composites, flax woven composites, and the hybrids respectively, the results of these tests are shown in figure 15. figure 12. stress-strain curves of wa and wb figure 13. stress-strain curves of fa and fb figure 14. stress-strain curves of the hybrids figure 15. stress-strain curves result from the composites comparison of the results between the wool woven and flax woven composites arranged by 0°/90° angle orientation and a combination of 0°/90° and 45°/-45° angle orientation, respectively, showed that the yield stress was higher by 10.976 % and 9.306 %, while, the max strain was higher by 4.599 % and 13.069 %. comparison results between hybrids (hwaf and hwajf) and wa showed that the yield stress was increased by 101.219 % and 46.951 %, respectively, while, the maximum strain increased by 8.81 % and 3.953 %. 4.2. fatigue results the stress fluctuated between maximum stress (σmax ) and minimum stress (σmin ) the stress ratio r = σmin σmax (2) for fully reverse stress: σmax = −σmin and for static stress: σmax = σmin [15]. the specimens of the fatigue tests were examined at fully reverse stress (r = -1), which was applied to the samples to investigate the number of cycles to fatigue failure. the s-n curve was obtained by testing a number of the specimens, which were subjected to a specific value of stress. starting with a high-stress value (less than the yield stress), the number of cycles (n) until rupture was counted. this procedure was repeated gradually by decreasing the value of the stress and counting the number of cycles for each test. figures (12, 13, 14, and 15) show s-n curves of fatigue tests for blends, wool woven composites, flax woven composites, and hybrids. all tests stopped when the number of cycles reached 106 cycles 92 ali jasim and ibtihal mahmood /al-qadisiyah journal for engineering sciences 15 (2022) 087–093 . figure 16. s-n curve of different composites figure 17. s-n curve of the wool composites figure 18. s-n curve of the flax composites the s-n curve was modeled using the parametric relationship known as basquin's law [64], which represents the relation between the stress and the number of cycles (n) until rupture on an s-n curve. there is no stress limit in the s-n curve for non-ferrous material, such as composite material. in these cases, the s-n curve is reached in a certain number of cycles (106 cycles), which is called the endurance limit (𝜎𝑒 ) [16, 17]. 𝜎 = a1𝑁 𝛽 (3) where: 𝜎 is the stress, 𝑁 is the number of cycles until rupture, a1 and 𝛽 are the adjustment coefficients characteristic of the material and the test conditions. figure 19. s-n curve of the hybrids the fatigue tests results of the blends and the composites are shown in table 3 and table 4 respectively, including the experimental s-n curve equations, the regression (𝑅2), ansys s-n curve equations, the endurance limit (𝜎𝑒 ) value at 𝟏𝟎 𝟔 cycles for the experimental and ansys results and the errors between them. comparing the experimental value of endurance limit (𝜎𝑒 ) between the pure epoxy with 5%, 10% and 15% of polyurethane blends, the endurance limit increased by 6.452 %, 12.061 %, and 12.421 % respectively. for the composites, wa has a higher endurance limit value by 15.174 % than wb and fa has a higher endurance limit value than fb by 11.632 %. hwaf and hwajf have higher endurance limit values than wa by 132.895 % and 66.549 % respectively 5. conclusions the main conclusions were withdrawn as follows: 1. mixing the polyurethane with epoxy decreased the yield stress and maximum stress while increasing the maximum strain. 2. the composites consisting of fiber arranged by 0°/90° have mechanical properties (yield stress, ultimate stress, and maximum strain) higher than composites consisting of fiber arranged by a combination including 0°/90° and 45°/-45°. 3. the mechanical properties of wa were improved at hybridization by fa and jute (hwaf and hwajf). 4. for blends, the endurance limit value and fatigue life improved by increasing the polyurethane percentages in the blends to a until10% percentage. 5. the composites consisting of fiber arranged by 0°/90° have endurance limit value and fatigue life higher than composites consisting of fiber arranged by a combination including 0°/90° and 45°/-45°. 6. the endurance limit value and fatigue life of wa were increased at the hybridization with fa and jute. ali jasim and ibtihal mahmood /al-qadisiyah journal for engineering sciences 15 (2022) 087–093 93 table 1. the fatigue tests results of the blends samples s-n curve equations fatigue strength at 𝟏𝟎𝟔 cycles (mpa) experiment r² ansys experiment ansys errors% ep σ = 61.569n-0.19 0.9829 σ = 60.59n-0.193 4.4603 4.2112 5.9159 pu5 σ = 52.543n-0.174 0.9793 σ = 55.521n-0.182 4.7480 4.4922 5.6958 pu10 σ = 51.62n-0.169 0.9784 σ = 57.563n-0.181 4.9983 4.7223 5.8442 pu15 σ = 54.728n-0.173 0.9729 σ = 60.58n-0.184 5.0143 4.7679 5.1672 table 2. the fatigue tests results of the composites sample s-n curve equations fatigue strength at 𝟏𝟎𝟔 cycles (mpa) experiment r² ansys experiment ansys errors% wa σ = 78.551 n -0.154 0.9616 σ = 81.86 n -0.159 9.3573 9.1006 2.8206 wb σ = 79.741 n -0.167 0.9588 σ = 82.173 n -0.171 7.9375 7.7398 2.5540 fa σ = 313.56 n -0.155 0.9718 σ = 332.64 n -0.163 36.8401 34.9925 5.2801 fb σ = 262.19 n -0.151 0.9640 σ = 318.42 n -0.169 32.5549 30.8319 5.5883 hwaf σ = 122.55 n -0.125 0.9411 σ = 128.46 n -0.131 21.7928 21.0265 3.6443 hwajf σ = 79.56 n -0.118 0.9760 σ = 85.245 n -0.127 15.5846 14.7458 5.6880 references [1] r. m. jones, mechanics of composite materials: crc press, 2018. [2] o. faruk and m. sain, biofiber reinforcements in composite materials: elsevier, 2014. [3] a. k.-t. lau and a. p. y. hung, "natural fiber-reinforced biodegradable and bioresorbable polymer composites," 2017. [4] f. c. campbell, fatigue and fracture: understanding the basics: asm international, 2012. [5] s. r. daniewicz, j. c. newman, and k. schwalbe, fatigue and fracture mechanics vol. 34: astm international, 2005. [6] a. h. abdullah, s. k. alias, n. jenal, k. abdan, and a. ali, "fatigue behavior of kenaf fiber reinforced epoxy composites," engineering journal, vol. 16, pp. 105-114, 2012. [7] a. r. saeed, "study of some properties of polyester resin reinforced by natural wool," engineering and technology journal, vol. 32, 2014. [8] f. bensadoun, j. baets, a. w. van vuure, and i. verpoest, "fatigue behavior of flax reinforced composites," in 16th european conference on composite materials, seville, spain, 2014, pp. 22-26. [9] t. hojo, z. xu, y. yang, and h. hamada, "tensile properties of bamboo, jute, and kenaf mat-reinforced composite," energy procedia, vol. 56, pp. 72-79, 2014. [10] s. asgarinia, c. viriyasuthee, s. phillips, m. dubé, j. baets, a. van vuuren, et al., "tension–tension fatigue behavior of woven flax/epoxy composites," journal of reinforced plastics and composites, vol. 34, pp. 857-867, 2015. [11] s. rana and r. fangueiro, advanced composite materials for aerospace engineering: processing, properties, and informed applications: woodhead publishing, 2016. [12] i. astm, "standard test methods for flexural properties of unreinforced and reinforced plastics and electrical insulating materials," astm d790-07, 2007. [13] n. roberts and n. r. hart, "alternating bending fatigue machine (hsm20), instruction manual," hi-tech ltd. uk, vol. 150, pp. 200-250, 2001. [14] ansys, ansys mechanical user's guide, 19 ed: ., ansys, inc, 2018. [15] s. suresh, fatigue of materials: cambridge university press, 1998. [16] v. carvelli, a. jain, and s. lomov, fatigue of textile and short fiber reinforced composites: john wiley & sons, 2017. [17] b. harris, fatigue in composites: science and technology of the fatigue response of fiber-re plastics: woodhead publishing, 2003. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� simulation of heat transfer haracteristics for flow of non newtonian power law fluids in tube hisham .m.al.tamimi college of engineering university of al-qadissiya abstract: heat transfer behavior for non-newtonian power law fluids flow in circular duct with laminar flow, fully developed, constant heat flux. and constant wall temperature was studied. a mathematical model which is capable of accurately predicting temperature and velocity profiles and heat transfer rates for power law non-newtonian fluids was obtained. the theoretical nussult number was compared with previously published works where good agreement was noticed, which can be easily evaluated using theoretical model as a function of power law index only for constant heat flux and as a function of power law index and graets number for constant wall temperature. it was found find that nussult number decreases when values of power index increases. keywords: heat transfer; non-notonian; power law fluid; power law exponent. "�!آ!ة y'!ص ا6�1!ل ا���ارة �m�:!ن ا���ا%w #�� ا���3����3 1 �بuذات 5!�1ن ا�6)رة �� ا dم ���� ا����� zه ا��>;ـ� d��ن ا��� � �kا� ��� � d�q ة وu��ن ا�u) ���uك ا(��� ل ا����ارة ���uا#�� ���� ا�u�7/����7 ذات � ��� � �uد �+ ./0 دراu��/ 0 و��� و�/ ��/ @�a ي �\ ا���رةwا� d� (��� و �)�ل ا(�� ل ا���ارة ���uا#� ا��wآuرة رkا� �aا���ارة و ا��� �rرة د ��� درu% و � ر 0 . ��r cqاu/ ك و � و�r ه7� � ل ��k7ة �a رنu ي�e7ا� y��)، d�� ���4ام ا��uد �+ ا�� y��) 0 ب ر �� ��u5� n�� و (uن ا��uة و ��)�ل ا���cq ا�� +� �اري ا�? y و آ�ا�� ��) �+ ا��uة و ر 0 آ� �� ?�uت در�r ���ارة ا���kار ا��e7ي آ�ا�� ��) . �k (uن ا��uة /�ر +� (� 0� � 7 �7a f /�ا� y��) 0 ر \) �rو. : nomenclature heat capacity of fluid, j/kg.k p c consistency coefficient for pipe flow at temperature of bulk fluid ( ) bp k consistency coefficient for pipe flow at temperature of wall ( ) wp k mass flow rate of fluid,kg/s m power law index n radial coordinate r al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� duct radius,m r fluid temperature, k t bulk temperature, k b t center temperature, k c t wall temperature, k w t density of fluid, kg/m 3 ρ thermal diffusivity of fluid α shear stress τ β coefficient of volume expansion gz graetz number nu nusselt number u velocity,m/s u mean velocity p pressure, n/m 2 introduction: fluids treated in the classical theory of fluid mechanics and heat transfer rate are the ideal (perfect) fluid and newtonian fluid. the former is completely frictionless so that shear stress is absent. the latter simply has a linear relationship between the shear stress and shear rate. since world ware ii, the study of real fluids used in the mechanical and chemical industries has become increasingly important; mainly because of sever limitations in the application of ideal and newtonian theories to real situations. most real fluids exhibit so called non-newtonian behavior, which means that the shear stress is no longer linearly proportional to the velocity gradient (popovaska, 1977). an understanding of the heat transfer behavior of these non-newtonian fluids is important in as much as most of the industries chemical and many fluids in the food processing and biochemical industries are visco-elastic in nature and undergo heat exchanger processes either application (gottifredi, 1985). the graetz-nussult problem in heat transfer theory involved the finding of the temperature profile and heat transfer rate in a fully developed laminar flow of newtonian and non-newtonian fluids inside circular ducts. several works (richardson, 1979),( rohsenow, 1985)and (shah, 1987) investigation this problem both experimentally and theoretically, unfortunate none of them presented complete analytical solution therefore the presents work attempt to: • developing a mathematical model, this is capable of accurately predicting temperature and velocity profiles and heat transfer rates for power law model non-newtonian fluids. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� p r e v i o u s w o r k : in view of its industrial importance heat transfer in tubes become the subject of considerable study of the main contribution have recently been comprehensive reviewed by (holland,1970) and only the brief summary of the various types of approaches will be given here. for constant heat flux condition, solution is available by (rohsenow, 1973) for circular ducts: )1...(........................................ 4 13 36.4 3/1       + = n n nu (gottifredi, 1985) modified the leveque correlation for non-newtonian fluids, by suggesting the following modified version of the relationship between the mean nussult number, nu, and the graetz number, gz, for constant wall temperature conditions in tube flow: )2...(.............................. )( )( 75.1 14.0 3/13/1       = b w kp kp gznu δ where n n 4 13 + =δ although, these correlations have little theoretical basis, but they have been used for engineering design purpose (bird, 1977). mathematical model: the governing equation for the graetz-nusslt problems is obtained by applying an energy balance for circular duct. the model was based on the following assumptions: 1. the flow is laminar and steady. 2. conduction of heat transfer in the axial direction is negligible relative to radial conduction, which is justified when re pr ≈ 100. 3. physical properties are constant. 4. no distribution for momentum and velocity in axial direction. 5. the tube wall temperature or heat flux is constant. on the basis the simplified equation of motion, energy and continuity are as follows: equation of motion al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� )3..(..............................).........( 1 τr rrx p ∂ ∂ = ∂ ∂ equation of energy )4.......(....................).........( r t r rr k x t upc ∂ ∂ ∂ ∂ = ∂ ∂ ρ equation of continuity ∫= r rudrpm 0 )5.(..................................................2π 1velocity profile in fully developed laminar flow: an analysis of laminar heat transfer for non-newtonian fluids requires an understanding of the hydrodynamic behavior of these fluids. the analytical procedure to obtain the velocity profile for non-newtonian fluids with the power-law model is exactly the same as for newtonian fluids except for the specification of the shear stress in the momentum equation. the assumption of the powerlaw fluid particularly in the laminar flow regime is a good approximation for most non-newtonian fluids. with the power law equation, shear stress in a circular tube is, )6......(.................................................. n rx dr du k       =τ using this equation and the equation of motion, equation (3). since the pressure is independent of r,the equation of motion can be integrated directly twice with respect to r and the boundary conditions: b.c.1 0= ∂ ∂ r u at r = 0 b.c.2 u = 0 at r = r yielding the fully developed velocity profile )7..(........................................)(1 4 )( 12       −−= + n n r r k r dx dp u however, it is more useful to express the velocity in terms of mean velocity u rather than the pressure gradient )( dx dp − . if we now substituted velocity in to equation of continuity, eqn. (5), and integrate to obtains: al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� )8.(.................................................. 1 )(1 1 13           + − + + = n n r r n n u u where )9........(..............................) 2 1 )(() 13 ( 1/1 n nn r kx p n n u +       ∂ ∂ − + = or expressions the results in term of the maximum velocity o u by using b.c.3 o uu = at r = 0 )10.(............................................................)(1 1       −= + n n r r u u o where       + + = )1( )13( n n u uo for n less than 1, this gives a velocity flatter than the parabolic profile of newtonian fluids. as n approaches zero, the velocity profile predicted by this equation approaches plug flow profile. 2temperature profile in fully developed laminar flow: there are at least two boundary conditions, for which it will be possible to integrate the energy equation directly with respect to r, treat it as an ordinary differential equation, the possible conditions constant heat flux and constant wall temperature: case i. constant heat flux: technically, constant heat flux problems arises in a number of situation; electric resistance heating, radiant heating, nuclear heating, and in counter current heat exchangers where fluid capacity rates are the same. therefore, the term x t ∂ ∂ is constant the applicable boundary conditions are: b.c.1 r = 0 t = tc b.c.2 r = 0 0= ∂ ∂ r t substituting into equation (4) the velocity profile, eqn. (10) to get : al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� )11.........(..............................)(1)( 1 1       − ∆ ∆ = ∂ ∂ ∂ ∂ + n n r r x tu r t r rr α o this equation can now be directly integrated twice with respect to r, )12...(....................)() 13 2 ()( 4 13 22 2       + − ∆ ∆ += + n n c r r n n r rr x tu tt α o for convenience tb is defined as the mixed mean fluid temperature, this temperature is sometimes referred to as the mass averaged temperature bulk fluid temperature, or mixing cup temperature. it is the temperature which characteristic defined the average thermal energy state of the fluid. this may be calculated from: )13.......(............................................................ 2 2 0 0 ∫ ∫ = r r b ucdrr uctdrr t ρπ ρπ if equation (10) and equation (12) are substituted for u and t, then this equation can be readily integrated to yield: )14....( ) 13 ( 2 1 ) 13 (2) 13 )( 15 ( 4 1 ) 13 ( 4 1 4 32 2       + −       + + ++ − + − ∆ ∆ += n n n n n n n n n n r x tu tt cb α o because )15..(..................................................)()( rrbw r t katthaq = ∂ ∂ =−= the heat transfer coefficient is calculated from: )16......(...................................................................... )( bw rr tt r t k h − ∂ ∂ = = the temperature gradient is given by:       + − ∆ ∆ == ∂ ∂ ) 13 2 (1 2 2 n nr x tu rr r t α o using b.c.3 r = r t = tw       + − ∆ ∆ += 2 2 ) 13 2 (1 2 n nr x tu tt cw α o substituting the two previous eqns. in to eqn. (16) gives: al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� )17....(.......... ) 13 ( 2 1 ) 13 (2) 13 )( 15 ( 4 1 ) 15 ( 4 1 ) 13 2 (1 13 2 12 3 2                 + − + + ++ − + − −    + −     + − = n n n n n n n n n n n n r n n k h or expressions the results in term of the nussult number as following : )18..(............................................................ 11231 )15)(13(8 2 ++ ++ = nn nn nu case ii : constant wall temperature : it occurs in such heat exchanger as evaporators, condensers, and in fact, any heat exchanger where one fluid has a very much higher capacity rate than the other. the term x t ∂ ∂ is not constant introduce the dimensionless quantities as followings z gru x r r twtb twt 1 ;; 2 === − − = α ξηθ and 1+= nn the dimensionless partial differential energy equation, eqn. (4 ) , can be written as : )( 1 )11( η θ η ηηξ θ η ∂ ∂ ∂ ∂ = ∂ ∂ +− n with boundary condition 1. 01 == ξθ at 2. 10 == ηθ for 3. 0= ∂ ∂ η θ at 0=η by applying the separation of variable technique and letting : )()(),( ηξξηθ rx= the substitution result two ordinary equation differential equation : x d dx 2β ξ −= 0)1()( 1 12 =−+ + r d dr d d nηβ η η ηη al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� the complete solution be a linear combination of products of the form : ∑ ∞ = −= 1 2 )19.........(........................................)(),( i ii erc ξβηξηθ where ci is arbitrary constant , which determined by using the first boundary condition and the orthogonality of the eigen functions can be evaluated from the following : )20.....(........................................ )()1( )()1( 1 0 21 1 0 1 ∫ ∫ + + − − = ηηηη ηηηη dr dr ci n n the integral in this equation can be numerically evaluated . we now turn to the evaluation of the nusselt number as : )21.(.............................. )( 2 )( 2 2 1 bwb rr tt r t r k hr nu θ η θ η = = ∂ ∂ −= − ∂ ∂ −== the temperature gradient as : )22(..................................................)1( 1 2 1 ∑ ∞ = = −= ∂ ∂ i iii erc ξβ η θ η )23.(............................................................ )( ),()( 1 0 1 0 ∫ ∫ = ηηηφ ηηηξθηφ θ d d b substitution the velocity and temperature profiles give : )24......(..................................................)1(2 2 2 ξβ β θ ii i i b er c −−= ∑ the nussult number is then given by : )25.......(.................................................. )1()( )1( 1 2 2 1 2 ∑ ∑ ∞ = ∞ = − − = i ii i i i iii er c erc nu ξβ β ξβ for large ξ we need only the term in each sum so that : 2 lim inu β ξ = ∞→ )26...(....................................................................... 2 i enui β= al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� results and discussions: a theoretical treatment is present which allows redial temperature and velocity profiles to be predicted when power law (ostwald equation) non-newtonian fluid in laminar flow with fully developed, constant heat flux, and constant wall temperature to exit in circular duct. for n (power law exponent) less than 1, this gives a velocity flatter than the parabolic profile of newtonian fluid. as n approaches zero, the velocity profile predicted by this equation approach plug flow profile .also for increasing value of n gradually, nu is decreases with constant heat flux and constant wall temperature the rate of heat transfer and the fluid exit temperature is simply evaluated by using temperature profile in equation (12) for constant heat flux and in equation (19) for constant wall temperature. it can easily be evaluated using theoretical model as a function of power law index only, for constant heat flux as in equation (18), and as a function of power law index and graets number for constant wall temperature as in equation (26). table(l) shows the results for different n values, the results can be compared with the corresponding predictions, where the asymptotic, downstream, nussult number for both the isothermal wall condition (constant wall temperature) and the uniform heat flux (constant heat flux) are shown in figure (1) conclusions: in conclusion, it is obvious from the above discussions that for n (power law exponent) less than 1, this give a velocity flatter than the parabolic profile of newtonian fluid. as n approaches zero, the velocity profile predicted by this equation approach plug flow profile .also for increasing value of n gradually, nu is decreases with constant heat flux and constant wall temperature. this work finds many practical applications in petroleum drilling, manufacturing of foods, production of polymers and slurries. more importantly, the boundary layer concept of non – newtonian power law fluid has application in the reduction of frictional drags in many engineering process. references: 1. a.r.monsour "an analitical solution of laminar heat transfer to power law non newtonian fluids in circular ducts graetz-nussult problem" int. com.heat mass transfer, vol. 16, pp.199204,(1989). 2. international editional, london,1 st ed,(1970). 2. holland and et.al"heat transfer" 3. f.popovaska and w.l.wikonson "laminar heat transfer to newtonian and non newtonian fluids in tubes" chem. eng. sci.,vol.32, pp.1155-1169,(1977). 4. j.c.gottifredi and a.f.flores"extended leveeque solution for heat transfer to non newtonian fluids in pipes and flat ducts "int.j.heat mass transfer ,vol.28,no.5,pp.903-908,(1985). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 5. r.b.bird, r.c.armstrong and o.hassager'dynamics of polymetric liquids " jon wiely &sons inc.,new york,vol.1,1 st ed.(1977). 6. r.k.shah,and w.aung"handbook of single –phase conective heat transfer "jon wiely &sons,new york, 1 st ed.(1987). 7. s.m.richardson "extended leveeque solution for flow of power law fluids in pipes and channels" int.j heat mass transfer, vol.22, pp.1417-1423, (1979). 8. w.m.kays "convective heat and mass transfer" mcgraw-hill, new york, (1966). 9. w.m.rohsenow, and j.p.hastnetti "handbook of heat transfer" mcgraw-hill com , new york, 1 st ed,(1973). table (1):nussult number for two boundary conditions constant heat flux ( x q ,uniform) constant wall temperature ( w t ,uniform) power index n nussult number nu eign value 2 1 β nussult number nu 0.0 8.000 2.408 5.800 0.2 5.517 2.203 4.851 0.5 4.746 2.013 4.050 0.8 4.468 1.937 3.752 1.0 4.364 1.897 3.603 1.5 4.214 1.857 3.452 2.0 4.134 1.844 3.400 3.0 4.051 1.841 3.391 4.0 4.007 1.838 3.383 2 4 6 8 10 0 1 2 3 4 power law inde x,n n u s s u lt n u m b e r, n u constant heat flux constant wall tem. figure (1): fully developed nussult number for laminar flow of a power law non newtonian fluid in a tube. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٧٧ improving transient stability in case of faults in haditha qaim line dr. samir s. mustafa technical institute / kirkuk abstract iraqi national super grid suffers from out of synchronism of the system due to short circuit in the lines. the main goal of this work is to study the effect of optimum generation and reconfiguration of some transmission paths on transient stability improvement for iraqi network in case of short circuit in haditha-qaim line because it is one of the wrest lines. a programmable package build under matlab5.3 was used to determine synchronous machines rotor angles as an indicator of transient stability. sad almosul, haditha and nasiriya power plant were chosen to notice the situation of stability. keywordspower losses, transient stability, stability, reconfiguration. ����� ا�����ار�� ا ����ة �� � � ا ��� �� �� ���� أ ��! – �ون ()'&%. د �� ��,� � أ���ذ (�� آ�آ3ك/ أ ,�0� أ ��/� ا �56� � ��� ا ��ا� وذ� ������ ��اق � ����� ��وج ا � ا� !"# � )'�� ا &%$ ا)"�. دا!�ة /.� �� ا�� �-�ط ا �'���وث* 34' ;إ�89ف ه5ا ا �< �� �d� e"راإ�"دة و*<=>� اab�c درا?� *<=>� اf a<��* ��"�fة �� )'�� ت ا g-�ط � ا�i�?jار�9 ا<d4* !"# �o ا g-�ط �� ا ������أ�� أ 9��'� m)c ا l!"i –��� ��وث دا!�ة /.� �� �$ ���b9 وذ ا &%$ اp . q�")�f ام�g�?ا l* �%�f ه�"smatlab5.3ب زوا9" دوار"d4 � ا�i�?jار�9 "4 �(vا��>� آ��� ا!"�� ���b9 و ، *l ا��>"ر �4-"ت *� >� ?� ا ��ax. ا ������ ����z أ?��iار�9 ا �9�x"� .ا introduction power system stability the importance of power system stability is increasingly becoming one of the most limiting factors for system performance. by the stability of a power systems we mean the ability of the system to remain in operating equilibrium, or synchronism, while disturbances occur on the system(kundur2004). there are three types of stability namely, steady-stat, dynamic, and transient stability. 1) steady-state stability: refer to the stability of a power system subject to small and gradual changes in load and the system remains stable with conventional excitation and governor controls. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٧٨ 2) dynamic-stability: refer to the stability of a power system subject to a relatively small and sudden disturbances .the system can be described by linear differential equation, and the system can be stabilized by a linear and continuous supplementary stability control. 3) transient stability t.s : refer to the stability of power system subject to a sudden and sever disturbance beyond the capability of the linear and continuous supplementary stability control, and the system may lose its stability at the first swing unless a more effective countermeasure is taken, usually of the discrete type, such as dynamic resistance braking or fast valving for the electric energy surplus area, or load shedding for electric energy deficient area. for t.s analysis and control design, the power system must be described by non linear differential equations. t.s concern with the matter of maintaining synchronism among all generators when the power system is suddenly subjected to sever disturbances such as faults or short circuits caused by lightning strikes, the sudden removal from the transmission system of a generator and/or a line, and any sever shock to the system due to a switching operation. because of the severity and suddenness of the disturbance, the analysis of transient stability is focused on the first few seconds, or even the first few cycles, following the fault occurrence or switching operation (shin2004),(selman2005). first swing analysis is another name that is applied to transient stability studies. if the generators can get through it without losing synchronism, it is said to be transient stable. on the other hand, if the generators losses its synchronism and can not get through the first swing, it is said to be transient unstable. there is a critical angle within which the fault must be cleared if the system is to remain stable( demetrios2005) . the transient stability calculations were carried out using the step by step modified euler iterative solution of the differential equations describing machines second and total solution time period of 1.5 second. the programmable package performs transient calculations with different behaviors of the system. the solution took into account a time step of 0.05 types of faults at any point on the system with 0.15 second clearing time (tc). rotor angles were taken as an indicator of transient stability. iraqi national network iraqi national super grid contains19 busbar,27 transmission lines and six generating sets of various types units, thermal and hydro turbine kinds, with different capabilities of mw and mvar generation and absorption as shown in figure 1.using the load data collected on 2/1/2003 in appendix a, the system line data as shown in appendix b which can be obtained from the iraqi control center (afaneen2004). iraqi electrical network suffered from serious problems. a great damage happened to the iraqi power system at all levels, the generation, the transmission and the distribution. there are tow dangerous regions , baiji and haditha because the loss of baigi or haditha busbars cause sad al -mosul to separate from the network, leaving it with high generation and low loading, and causing the instability of the bus. while the separation of haditha causes the losses of large amount of power feeding the al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٧٩ middle area , and forcing the network to overcome this loss from sad al -mosul. this lead sad al mosul to swing highly reaching the instability. improving the stability. the following steps were tried by (afaneen 2004) to overcome this problem: 1 recovery of damaged transmission line. those are (mosul – kirkuk line, one of the double lines of sad al mousil – baiji, one of the double lines of harthakhour al-zubair ……etc). table 1, represents the type of stability and the critical clearing time(tcr) for each step of generating units cancellation with and without the recovery of the separated transmission lines (t.l). although the installation of the recovered transmission lines will lead to improvement in the power flow in the north and middle regions, they did not affect the stability situation of the network. increasing the generating power of the generating units. ٢ 3. as shown in table 2, increasing the generating power has no effects on the stability of the system when removing haditha. the effect of optimum power generation on transient stability three buses(sad al-mosul, haditha and nasiriya) power plants were chosen to study the effect of three phase fault in the middle of the line haditha-qaim. the system is unstable in case of ordinary load flow because sdm plant is out of synchronism. the system becomes more stable (but still unstable)with optimum power generation using the data of optimum power generation in appendix c (samir2007). 1 stability improvement calculations for sad al-mosul the difference in the rotor angle for the swing curve in case of ordinary generation as shown in figure 2= 330-20 =310degree. the difference in case of optimum generation as shown in figure 3 = 100-5= 95degree. the stability improvement between ordinary and optimum generation= 310 95310 − = 69.35% 2 stability improvement calculations for haditha the difference in the rotor angle for the swing curve in case of ordinary generation as shown in fig4= 15-(-75)=90degree. the difference in case of optimum generation as shown in figure5 = 10-(-15.5)=25.5degree. the stability improvement between ordinary and optimum generation= 90 5.2590 − = 71.6% 3 stability improvement calculations for nasiriya the difference in the rotor angle for the swing curve in case of ordinary generation as shown in figure 6= 10-(-85)=95degree. the difference in case of optimum generation as shown in figure 7 = 7.5-(-22.5)=30degree. the stability improvement between ordinary and optimum generation= 95 3095 − = 68.4% al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٨٠ the effect of paths reconfiguration on transient stability as shown before the network is the unstable, during both ordinary and optimal load flows, in case of three phase fault in the haditha-qaim because this fault will lead sad al-mosul bus to swing away from the stability and cause instability of the system. to overcome this problem a new configuration of the network will solve this problem. if the radial path (baiji-haditha-qaim) as shown in figure(1) is changed to a loop path (baiji-qaim-haditha-baghdad east-baiji), the system becomes stable for both ordinary and opf as shown in swing curves figures (8-13). stability improvement calculations the improvement calculations are done in procedure similar to that in 4.1, 4.2 & 4.3. in case of ordinary generation, the improvements in stability using the new configuration are equal to 96.4%, 63.8% and 59.6% for sad al-mosul, haditha and nasiriya respectively with respect to ordinary generation without new configuration as shown in figures8, 9 & 10. in case of optimum generation, the improvements in stability using the new configuration are equal to 97.4%, 67.9% and 50.8% for sad al-mosul, haditha and nasiriya respectively with respect to optimum generation without new configuration as shown in figures11, 12 & 13 . conclusion 1) comparison between stability with optimum generation and ordinary generation according to the rotor time angle curve indicates that transient stability is much better with optimum generation. 2) in case of 3-phase fault in the middle of line haditha-qaim, transient stability can be enhanced using optimum generation but the system remains unstable. 3) the system becomes stable if a new configuration is used. references • afaneen a. abood (2004), implementation of geographic information system in realtime transient stability, ph.d thesis, university of technology, baghdad. • demetrios a. tziouvaras(2005), out-of-step protection fundamentals and advancements, wwselinc.com/6163 pdf. • kundur k(2004).,system stability, www.ee.und.ac.za/ course main. • samir s. mustafa (2007), minimum power losses based optimal power flow for iraqi national super grid and its effect on transient stability, ph.d thesis, university of technology, baghdad. • selman n. h.(2005), minimum energy loss based reactive power flow, m. sc. thesis, university of technology • shin-min hsu (2004), power systems-basic concepts and application,www.pdhcentre.com. . al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٨١ table (1)the stability situation during the recovery of the separated transmission lines tcr(sec)with the recovery of t.ls the system stability the separated bus-bar ٠.٠٠١٢٣١٢ unstable baiji ٠.٦٩٤٧٠٢١ stable sad al-mosul ٠.٠٠١٢٣٠٦ unstable haditha ٠.٧٧٧٠٢٤٩ stable mussayab ٠.٤٠٥٦٤٠٥ stable nasiriya ٠.٥١٠٤٢٥٣ stable hartha table (2)the stability situation after increasing generated power of the generating bus-bar tcr(sec) the system stability the generated power(mw) the separated bus-bar ٠.٦١٥٢١٠١ stable ٨٠٠ baiji ٠.٦٨٠٢٤٥٧ stable ٨٠٠ sad al-mosul ٠.٠٠١٢٣١٥ unstable ٦٠٠ haditha ٠.٥٥٥٥٩١٤ stable ١٠٠٠ mussayab ٠.٤٦٥٢٥٩٢ stable ٧٥٠ nasiriya ٠.٢٤٤٨٤٤٩٦ stable ٧٠٠ hartha figure (1) iraqi national super grid al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٨٢ figure 2: swing curve for (sad al-mosul) generator figure 3: swing curve for (sad al-mosul) generator with ordinary power generation with opf figure 4: swing curve for (haditha) generator figure 5: swing curve for (haditha) generator with ordinary power generation with opf figure 6: swing curve for (nasiriya) generator figure 7: swing curve for (nasiriya) generator 0 0.5 1 1.5 -80 -60 -40 -20 0 20 40 rotor angle in degree for gen. had4 time[sec] 0 0.5 1 1.5 -20 -15 -10 -5 0 5 10 15 20 rotor angle in degree for gen. had4 time[sec] 0 0.5 1 1.5 -100 -80 -60 -40 -20 0 20 rotor angle in degree for gen. nsr4 time[sec] 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 -20 -15 -10 -5 0 5 10 15 20 25 rotor angle in degree for gen. had4 time[sec] mid 3-4 fault(mod) 0 0.5 1 1.5 0 50 100 150 200 250 300 350 rotor angle in degree for gen. sdm4 time[sec] 0 0.5 1 1.5 0 10 20 30 40 50 60 70 80 90 100 rotor angle in degree for gen. sdm4 time[sec] al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٨٣ with ordinary power generation with opf figure 8: swing curve for( sad al mosul) generator figure 9: swing curve for (haditha) generator with ordinary generation& new configuration with ordinary generation& new configuration figure 10: swing curve for( nasiriya) generator figure11: swing curve for (sad al mosul) generator with ordinary generation& new configuration with optimum generation& new configuration 0 0.5 1 1.5 -25 -20 -15 -10 -5 0 5 10 rotor angle in degree for gen. nsr4 time[sec] 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 10 15 20 25 30 35 40 45 50 rotor angle in degree for gen. sdm4 time[sec] mid 3-4 fault(mod) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 -30 -25 -20 -15 -10 -5 0 5 10 15 rotor angle in degree for gen. nsr4 time[sec] mid 3-4 fault(mod) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 5 10 15 20 25 30 rotor angle in degree for gen. sdm4 time[sec] mid 3-4 fault(mod) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٨٤ figure 12: swing curve for(haditha) generator figure13: swing curve for (nasiriya) generator with optimum generation& new configuration with optimum generation& new configuration appendix a: insg system load data generation load bus bar number bus bar name type mw mvar mw mvar 1 baj slack 570.592 100.4455 200.00 98.00 2 sdm p,v 700.00 23.2248 5.00 2.00 3 had p,v 500.00 0.8474 100.00 60.00 4 qam p,q .00 .00 60.00 40.00 5 mos p,q .00 .00 300.00 180.00 6 krk p,q .00 .00 70.00 40.00 7 bqb p,q .00 .00 150.00 80.00 8 bgw p,q .00 .00 500.00 360.00 9 bge p,q .00 .00 500.00 360.00 10 bgs p,q .00 .00 100.00 50.00 11 bgn p,q .00 .00 300.00 200.00 12 msb p,v 600.00 420.6564 120.00 70.00 13 bab p,q .00 .00 100.00 50.00 14 kut p,q .00 .00 100.00 60.00 15 kds p,q .00 .00 200.00 100.00 16 nas p,v 650.00 69.1434 100.00 54.00 17 kaz p,q .00 .00 350.00 200.00 18 hrt p,v 380.00 35.9855 38.00 22.00 19 qrn p,q .00 .00 70.00 30.00 total 3400.592 463.8716 3363 2056 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 -8 -6 -4 -2 0 2 4 6 8 10 rotor angle in degree for gen. nsr4 time[sec] mid 3-4 fault(mod) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 2 4 6 8 10 12 14 16 18 rotor angle in degree for gen. had4 time[sec] mid 3-4 fault(mod) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٤٨٥ appendix b: insg system line data from to r (p.u) x (p.u) b (p.u) baj4 sdm4 0.00542 0.0487 1.4384 mos4 sdm4 0.00143 0.0124 0.36439 mos4 baj4 0.00399 0.03624 1.074 baj4 had4 0.00364 0.03024 0.8676 qam4 had4 0.0035 0.03 0.7413 bge4 bqb4 0.00076 0.00689 0.2043 baj4 krk4 0.00182 0.01654 0.49031 baj4 bgw4-2 0.0055 0.05004 1.4826 baj4 bgw4-1 0.00483 0.04393 1.3017 had4 bgw4 0.00483 0.04393 1.3017 bgw4 bgn4 0.00093 0.00847 0.25099 bgn4 bge4 0.00029 0.00265 0.0788 krk4 bge4 0.00481 0.04373 1.29581 bge4 bgs4 0.00105 0.00955 0.28309 bgw4 bgs4 0.00144 0.0131 0.38816 bgs4 msb4-1 0.00121 0.0102 0.30944 bgs4 msb4-2 0.00121 0.0102 0.30944 bab4 msb4-1 0.00077 0.00648 0.19666 bab4 msb4-2 0.00077 0.00648 0.19666 bgs4 kut4 0.00245 0.02236 0.6625 bgs4 kds4 0.00292 0.02659 0.788 kds4 nsr4 0.00383 0.03486 1.03314 kaz4 nsr4 0.00439 0.03999 1.1849 kut4 nsr4 0.00433 0.0394 1.1674 kaz4 hrt4 0.00119 0.01083 0.32104 qrn4 hrt4 0.0013 0.01182 0.35022 qrn4 kut4 0.00628 0.05713 1.6927 appendix c: optimum power generation according to system data load(samir2007) generation bus name optimum generation[mw] baiji 571 sad al-mosul 250 haditha 350 mussayab 1000 nasiriya 500 hartha 400 al-qadisiyah journal for engineering sciences 13 (2020) 109–124 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: shamms51@yahoo.com ( shams a. ameer) https://doi.org/10.30772/qjes.v13i2.657 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. void formation in digital architecture interfaces basim hassan almajidia , shams abdul ameer kafi a* a university of technology / department of architecture, baghdad, iraq a r t i c l e i n f o article history: received 03 may 2020 received in revised form 16 june 2020 accepted 26 june 2020 keywords: void digital formation interfaces digitization a b s t r a c t in the last era of the digital revolution, architectural outputs with distinctive void formations appeared. the development in digital technologies, which adopts solid geometry in the formation of its interfaces. so the void became an integral part of the design at the level of three dimensions, to serves as a fourth dimension of architecture. by connecting architecture with the time, the limits of length, width, and height fade away and change from the limits of place to those of time, and this void shifts out from achieving the aesthetic needs to achieving functional and structural needs. the direct correlation of the architectural void with the process of forming the interfaces led it to be considered as a basic architectural formation unit, and in light of this, the research problem was presented as (insufficient knowledge about the importance and role of the three-dimensional architectural void and the mechanisms of its formation in the interfaces of contemporary digital architecture as a void that generates or creates the design within the needs of the designer and the receiver ). the aim of the research came to reveal the concept of architectural void at the three-dimensional level, as well as revealing strategies and mechanisms for shaping the void in the interfaces. the research adopted the descriptive and analytical research methodology in proposing theoretical knowledge extracted from previous studies of building the theoretical framework for the geometry terms which contains (strategies for forming digital void, characteristics of void in digital output, features of digital spatial structure), and applying it on contemporary architectural models with a qualitative measure that is aimed at knowing the effect of terms on the selected samples and the percentage of their effectiveness in the characteristics of the digital output, and verifying the main research hypothesis which stipulated the adoption of the strategy of forming the digital void to combine the mechanisms of digital formation that is used to create void formation to meet the needs in contemporary architecture. the results indicated that the disappearance of the boundaries between the interior and exterior over time led to the use of the void in the formation of the building’s outer mass at the three-dimensional level so that the formation of the mass is based on that void which is called (designgenerating void) and the structure which is created by the void called (the spatial structure), as its formation depended on "geometry" and its methods of formation. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the new prospect of digitization was reflected in various fields of architecture, including the architectural void, which is considered as a generator of design in the interface, in order to create dynamic space configurations that are compatible with the era of the digital revolution in which the boundaries between the exterior and the interior fade away. so the void that the research deals with is emerging from the interference between the exterior and interior voids. it is related to the context on one hand, and inside the building on the other hand, so the architectural void appears as a dialogue area between fragmented or segmented pieces, or as a spatial interlock and merging area to convey the state of architectural formation to a state of permanent formation to achieve interactive output through the idea of formal manipulation and the principle of deletion and interference between mass and void, thus impedes the monotony to create new relations between the contradictory parts. when the void participates http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i 110 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 in the formation of the interfaces, it works within the fourth dimension which is represented by the time. thus, there is a need to clarify the connection between the void and the digital architectural formation, up to the role and importance of the void in the digital architectural formation. accordingly, the research problem has been stated as follows: (insufficient knowledge about the importance and role of the threedimensional architectural void and the mechanisms of its formation in the interfaces of contemporary digital architecture as a void that generates or creates the design within the needs of the designer and receiver). for the purpose of solving the research problem, the approach has been divided into five parts, the first of which was to study the basic concepts of the research "architectural void, and architectural formation in interfaces". the second: included building the knowledge framework for the formation of a digital architectural void. while the third focused on building the theoretical framework through the analysis of the literature and previous studies. as for the fourth: it dealt with the elected projects for the purpose of application. and finally, the fifth presented the conclusions and recommendations. 2. the conceptual framework of the research: the theme discusses the concepts of architectural void and digital formation in an attempt to understand its effect on shaping the interfaces of contemporary digital architecture and its characteristics. 2.1. architectural void: the paragraph explains the concept of void in two main aspects and as follows: first: linguistically and idiomatically: the void in english is defined as the empty space or everything is empty and not filled or does not contain anything, or the state of being without something and a complete absence of the contents [1] and is defined by almawrid dictionary as the meaning of vacuum in the sense of loss or emptiness. or void is a thing which is free or vacant. aljami dictionary defines it as a vacancy or empty place and the plural form is voids. al-musbah al-munir dictionary defines it as emptying something of another thing or removing it. [2] aristotle mentioned in his definition of void as "a container for things". as for plato, the void is considered in his theory as a continuous and constant quantum. whereas the later theories of void were adopted on the basis of euclidean geometry more than aristotle’s hypothesis and defined void as an absolute and infinite homogeneous element and one of the fundamental dimensions in the universe. after 1800 years, “kant” considered the void as a kind of human understanding that differs and is independent from the subject, but in the twentieth century, «descartes» gave an approximately clear concept of the physical space and this concept is still important as he considered any engineering is a human establishment more than being something in nature. void is an intangible thing that has an emotional relationship with the human which controls it, expressing its thought and attitude towards the circumstances surrounding it. thus, the theory of relativity replaces the three-dimensional idea with a four-dimensional idea in which the time factor directly participates. [3] secondly: the void in architecture: the architectural void is defined as the embodiment of the absolute general void interacting with human existence. cheng says that the elements of form and void constitute the truth of architecture [4]. lawson believes that the value of architectural work comes from the value of void, architecture and architectural voids accommodate, separate, structure, organize and celebrate human spatial behavior. "the role of architecture is to regulate the void and its structure," lawson says. [5] the philosophy of void lies in considering it as a created void that the architect arrives to with a type of abstraction that creates a distinctive view that can be felt, and its influence, which increases in strength and weakness, changes depending on the nature of the formation of the void, and this is the essence of the architecture that the architecture should mainly seek. as for lewis khan, architecture is also known through the role of void in it and says: “it is a studied formation of void” [6]. void is also considered as a three-dimensional space that surrounds us or an area of an architectural form. [7] al-dahwi explains that the effect of the abstract school on the concept of a void was through two aspects: an expressive abstract aspect and a material abstract aspect; the first called to reduce drawing to a group of a few signs of slight intensity, generating void through the interference between the inside and the outside and from a study of the relationship between void and time, which aims to abolish " the inside and outside dualism” as well as the non-identical and unstable formation; and dealing with void in continuous, interrelated or intersecting relations. while the "material" abstract side appears in achieving open and transparent void and achieving overlap between the inner and outer spaces [8]. from the above, it becomes clear that the void in architecture represents a framework for social and cultural forms, determined by the elements surrounding it and is within the formation of the mass at the three-dimensional level, and it results from studied relations of architectural formation with the aim of enriching the function or symbolic significance. 2.2. formation: the paragraph clarifies the concept of formation in two main aspects: first: formation in architecture: the architectural formation is represented by the outside sensory appearance of materials which consists of a system of properties for the formative elements and sensory relations between them, whether in the horizontal level or volumetric or spatial formation. architectural formation begins with knowing the sensory characteristics of the various regular forms, from which we conclude some values that control the relations between masses and architectural voids. the formative process is defined as the organizing of a set of elements within a ruling framework of relations and foundations that define how these elements exist in relation to each other and they are linked to two main goals, which are the utilization and beauty, where architecture represents a usable spatial space that meets human requirements. modern technology strongly influenced those formative elements and gave a great deal of freedom and flexibility to the architectural formation. architectural formation means formulating the architectural form in a way that results in new features and new relations, similar to the artist when sculpts the block, to bring out organized forms and areas that change the ambiguity and illusions into forms with distinct meanings and spirituality that are compatible with modernity and achieve communication between the formative elements and modern systems. [9] it is clear from the above that formation, in general, is the process of creation and innovation, that is collecting elements and placing them in a specific formation to give something with a specific function or meaning and unique characteristics, in which human thinking and personal experiences interfere. second: digital formation: the digital formation is seen as a set of methods which employ the computer not as a display tool, but as a generator for finding and transforming the form. the goal is to make the computer a designing tool in order to find a generating system that helps basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 111 in architectural design, where the difficulty lies in finding the boundaries and variables that define the design process, as there must be a cooperative relation between the human mind of man and computer systems, and this cooperation can be achieved only through the use of logarithmic strategies that emphasize an integrative and dialectical relation between a person and a computer. [10] the digital formation is defined as the generative processes based on parametric values, the role of the designer is limited to deciding on the main axes that define the form, then unleashing the program in order to perform the computational operations which produce the final form. [11] digital forms are defined as those forms which their design depends on the use of the digital language and the computer as a basis for the design. later, these forms spread in various engineering and technical fields, so they came as an expression of experiences for a new generation of renewed theories of sculpture, architecture, and forms. they represent a new trend that is increasing and spreading, and this new idea has been reflected in various fields of architecture. [12] from the above, it is clear that the change in the design process due to the use of digital means has provided new design capabilities for the production of free and dynamic forms with endless capabilities in finding the form generated by digital tools. the architect in the digital design process uses computer models to manage the design process and the generative internal logic of the model generates the form, then the architect chooses the form from among the various possible forms that the program produces and this moved the architectural design from (making the form into choosing the form), as the digital generation process of the form opens up new horizons for architectural thinking and the resulting form. 3. the cognitive framework of the research: it discusses the formation of the architectural void from several basic areas which are the dimensions of the digital void, the architecture of its formation at the two-dimensional and three-dimensional levels, and explaining the strategies, mechanisms and rules of digital void formation in the interfaces of digital architecture, in addition to explaining the most important features and characteristics of void creation. 3.1. the structural dimension of the architectural void: the void and mass represent an integral unit. they are inseparable. the structure of the void can only be formed by knowing the mass, and vice versa. by forming mass through the physical elements, the void is formulated, and by the difference in the relation between the void and the mass, several voids are produced (internal, external, and middle voids). the level of the relation between the void and the mass, i.e. the strength or weakness of this relation, can be determined by what is between the specific surfaces of the void. the flatter it is, the weaker the relationship and vice versa whenever the middle void emerges through its elements, that relationship strengthens. [13] the non-physical nature of the void gave it multiple capabilities for its relation to other voids, which allowed for a variety of design relations in different architectural works. [14] the idea of overlap and transparency appears in the formation of the void structure through the overlap in the future glass architecture. interference weakens hierarchical models at all social and architectural levels, so interference is a multiple character. as it is possible to achieve the void formations in the design based on the basic design elements which include (rhythm, unity, proportionality). technologies have a great role in achieving the architectural orientation, whether in terms of simplicity or complexity. with the required speed in construction and for the ability of some materials to form regular or irregular forms, they played a role in shaping the structure of the architectural void, and this was reflected in architectural works, complex configurations, and free and dynamic forms. [9] so, the term of void formation is used to refer to the capabilities of three-dimensional lines in interacting with the voids surrounding and within them. the linear formations which are characterized by being a separate entity in a void have a void activity that may appear as an element in which it is able to find a void. the three-dimensional spatial structures in addition to the spatial dimension, give a sense of the formal composition (volumes) and motion in a continuous integrated building unit and an unordered rhythm of its being in a specific environmental form and conditions. [15] it is clear from the foregoing that the structure and formation of the void result from spatial interference through the closure or openness between the mass and size, so the formed void is of high transparency and contributes to achieving integration and interference between the interior and exterior, and the use of the architectural void represents an evocation of the entire symbolic meaning as it gives the idea of division and expresses an idea in the mind of the designer and these ideas are multi-meaning to the recipient, thus the void exceeds the physical needs to achieve sensory and emotional needs. this led to the creation of an emerging corrective style that works within the three dimensions of the building without breaking the main composition of it, and employing these voids to achieve needs further than the aesthetic needs such as environmental needs to achieve vitality of the structure and creates interaction between visitors through motion and interference produced by the voids in the composition of the building. 3.2. geometry at twodimensional level (2d): geometry is the science that searches in mathematical concepts related to line, surface, square, congruence, equivalence ... etc. as well as looking at the application of these relations in the practical aspects of life. it is also a science that studies space and magnitude, and it is concerned with the position, form, area, and size of form and solids without addressing their physical properties. the term solid geometry is the engineering that deals with forms and solids in a three-dimensional void. dr. khaled mahmoud proposes the geometry, or what he calls (the architecture of void forms) by explaining the link between the architectural formation of buildings from ancient times with the basic geometrical special forms. with the emergence of the digital revolution and its applications through that trend in the fields of architecture and design, the innovative treatments for these basic geometrical spatial forms and in order to achieve various purposes and goals, ranging from activating the building’s functional efficiency or raising the efficiency of its climate and environmental treatments, or even just to those same formative and visual goals, as well as other purposes and objectives. [16] four basic vital relations can be distinguished to form an architectural void, including the following: first/ void within void: a large void can contain a smaller one within its volume. therefore, we find that the spatial and visual continuity of the two voids is easily embodied, but the smaller content void depends on the larger. [4] second/ interlocking or overlapping voids: a spatial interrelationship is produced by overlapping two spatial domains, which results in an area of a common void. the intersection of two void forms creates a common void, with characteristics that differ from both voids. this intersection somehow affects the properties of the two voids as well, 112 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 and the area formed by the intersection can be equally dependent on both voids, so that the three voids appear to be of one space, or the common space can be part of one of the two voids and completely taken out from the other void. [4] third/ the adjacent voids: the degree of visible and spatial continuity that appears between two adjacent voids depends on the nature of the surface that separates them and connects them together. it may include a change in the level of variation in the surface material or in the fabric (structure) between the two voids. [4] fourth/ voids associated with an intermediate void: two voids separated by a certain distance can be linked to a third, intermediate void. here, the visual and spatial relation between the two voids depends on the nature of the third which is connected with them by a general link. the intermediate void can differ in terms of formation and orientation from the other two voids to express the fig. 1-b void as a kinetic optical link element in the 3d plane [14] interconnection function between them, and the formation of the intermediate void may be residual in nature and specific as a result of the configurations and directions of the other two interconnected voids. [4] according to the foregoing, it is clear that the formation of the void at the two-dimensional level involves clear rules between the elements, out of the idea of simplifying the components, preserving the form of the voids, and making use of those voids without waste. therefore, geometry must be studied and understood to be adopted as a generator of design and an architectural formation unit which shapes the outputs of contemporary architecture. 3.3. geometry at the three-dimensional level (3d): void is defined in geometry as what is determined by three orthogonal dimensions, so it is known to have dimensions of length, width, or height, and the proportions that link these dimensions are recognized, as well as the ratio of the dimensions of the void to the ratio of its human dimensions [14]. in this context, three-dimensional forms are defined as forms which contain points, lines, surfaces and bodies in a blank image, among which is the solid form which is considered one of the strongest forms as it is a mass that is handled by sculpting, removing or adding and it can be called a structural form or complex compound which is based on a group of connected bars together in the horizontal, vertical, diagonal or any other direction to make the final form, and finally, the surface form which consists of a group of horizontal, vertical, inclined or rotational surfaces that can be separated from one another or interlocking. [9] the space can be defined in the interfaces as being the incubator of the mass in coexistence and harmony so that the mass does not overwhelm the space and the space does not weaken due to the strength of the mass. burnham believes that the void is an effective and positive element for its ability to connect volumes to each other as if it were a connecting force or a communication link like any other solid material with its properties and effectiveness because it is a structural part of the same form. the void is not only part of the cosmic space that surrounds only the form, but rather a substance itself. [17] the void resulting from the positioning of forms must be treated with the same importance of the forms, so it is called the negative space when it does not represent a certain dimension after the forms are positioned in it, and it is called the positive space if the form of the void that is trapped between the forms has a certain form. [6] the three-dimensional theory (solid-void theory) shows that the volumetric voids formed by the positioning of solid forms are of a higher importance than these forms themselves. the threedimensional void is considered a positive space if it has a specific form and gives a sense of borders or is a threshold for moving from the outside to the inside. [6] the void is formed by deleting the space of the elements that it is defined by. if the boundaries of the void are clear, defined, and identifiable between the inside and outside, then the void formed is called a defined space. otherwise, it is considered as an undefined space. [14] there is a great diversity in the methods of organizing building mass to confirm the spatial dimension between them. it is necessary to know the organization of the masses and the relation between void and solid, to reach the required design goals. the following figures illustrate some methods of organizing the mass in order to reach the required level. [18] when two closed voids intersect, the result is the volume formed by the merging of the two voids together, and there are major possibilities for the result of the intersection, so sometimes the void forms a central connecting element between the other elements. sometimes, the void is a visual kinetic element when it is in the three-dimensional plane, often extending over the entire height of the building and is often characterized by coverage of a different nature in terms of form or transparency or the possibility of opening to the outer void from the rest of the voids, which gives the void distinct characteristics. the true value of this void does not come from its utilitarian only, as it is not of a necessarily major function, but its role in connecting the voids and the volumetric and visual composition of the design is what gives it the value for being the heart of the work or the engine of the design. [14] figure 1-b. void as a kinetic optical link element in the 3d plane [14] figure 1-a. sculpture in the block [18] it is clear from the above that the role of the three-dimensional void with its various forms in the design process is to connect and regulate the relation between other voids and form elements. so this process is affected by the nature of the geometrical form of the void, so each form has its own characteristics and controls the relation between the elements, so the form of the void affects the relations between the void and the design elements. 3.4. interfaces and formation of digital architecture: displaying a module of external structural elements in the interfaces of free formations enriches these interfaces and organizes the formation and helps to define the non-standard form of the curved walls by emphasizing the three-dimensional curves, accordingly, our understanding basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 113 of these formations increases. [19] the spatial formation system has changed from being central to multiaxial design and formation and deviated from the traditional design network. it has also shifted mainly from the regular and the basic geometrical forms to the irregular, folded, deformed, and disjointed forms to shape a new, stand-alone noneuclidean system which was reflected on the interfaces. [20] the use of the modular system which is clear on the interface gives the envelope layer several characteristics, including:  the ability to amend and configure the interface modules.  the module allows manipulating the scale of the building "change the beholder's perception of the scale of the building".  the module generates styles that regulate the outer envelope, enrich it with rhythm and hierarchy, and make it visually enjoyable.  shows the structural elements in buildings.  in free and irregular formations, the display of structural rib modules leads to organizing the formation and determining the nonstandard form of the building. as for the types of the modular network, they include: (the systematic modular network linear diagonal radial circular the modular network which follows the geometric form the spatial modular network). [19] if the depth and the modular characteristics are combined in the structural elements on the outer envelope, they give the building spatial formations and a dynamic interface in the formation. [21] the irregular void formation led to the generation of the concept of vital, malleable void, which is embodied by the flexibility to organize and liberate the elements of the void from explicit geometric relations, where the malleable forms are related to dynamic effects, and thus the void is full of motion and has no specific systemic form or any geometric axis. [22] the void is formed by combining two volumes or two closed voids which gives a distinction to the void and is often added to attract attention to an important point of the design. this void is directly related to the axes of external motion, and therefore makes a transportation void between the outside and inside of the building. when an open void intersects with a volume, the result is the process of cutting off the joint part of the two forms. in other words, the process of the intersection of mass and void, is a process in which the mass is being emptied to fit that void, and the dimensions of the void are close to the dimensions of the internal volume so it is highly dynamic and has a central polarization point. when the dimensions of the void are greater than the dimensions of the volume, it becomes more dynamic information, and the architectural ties between the surrounding masses are weakened and the design becomes closer to the urban formation. the void creates a space and a dynamic link between the volumes that have less openness to the void. [14] figure 2. forming a void in facades [14] 3.5. the digital dimension of architectural void (digital void): in physics, the structure of the digital void consists of an added void or a separation area (a void between masses), the formed void is related to the mass, whereas the separation area is related to kinetic energy, so the separation void collects about three different forms: (the non-mixable area, binary partition area, and the binary grid area of the threedimensional void). [23] in the digital architecture, the importance of adopting (camcad) has been noticed to create hypothetical forms that combine natural forms (organic and inorganic) and engineering (irregular and nonlinear) with correlations similar to those in biology and cosmic science to create free forms with unique spatial configurations or so-called spatial creation, through containing the void of the event and adding the time as a fourth dimension to the void, as architectural ideas are developed in digital data by interactive and dynamic means which enable the designer to explore the relation between the technique of the form and its development by computer, as well as the choice of components, materials, texture, and structure of the form, in addition to the ease of the processors for the designer. [24] the digital model which is formed according to the concept of self-organization, for basic units over which energy is projected to overlap with each other to form a specific pattern of the form, is subject to transformations at multiple levels of the form pattern at the level of the parts and their relation between them and all others with the diversity of the relations between them by attraction or repulsion. transformations occur in the relation of the part to the part of identical elements from states of repetition and transit. as for the transformations of the level of the relation of the part to the whole, it produces positive and negative elements. as for the positive elements, they represent the emergence of a specific formation (addition), and the negative parts work as the background of the elements which generate a void which is considered a container and organizer for the rest of the elements by (deletion). this is what happens in real life, with the growth of spatial geometrical forms from simple rules in which the parts are formed with high engineering at the level of the part and coherence at the level of the whole. [25] the digital void is considered as a part of the imaginary reality of the building, as it creates the different threedimensional spatial formulations according to the factors of time and motion, and clarifies the form of one of the applied tools of the virtual reality. these applications fall within the scope of how to show architectural work as well as to evaluate the design process in greater depth for creative persons and judge them before the implementation. the digital void is formed by two states of static and dynamic. [26] according to the above, it became clear that the elements of architectural formation are affected by digitization, especially the architectural void, as its dimensions have changed due to its association with time and has become a fourth dimension of architecture, and therefore the dimensions of the digital architecture outputs have changed from the traditional dimensions of (length * width * height) to the digital dimensions represented by (length * width * height * time). first/ the static digital void: the static void is designed by organizing the void elements in a formal relation, i.e. symmetry can control the whole void, as it is an independent void with respect to adjacent voids, and does not usually give a sense of direction and does not suggest any motion in it. the static void may be a memorial measure independent from the viewer, but it may be influential in its size, and the viewer can realize all the void at the same time from one standing point. [22] avoid is formed by the deletion or cutting off of space by surfaces or elements that define the void and give to its properties. thus, the formed 114 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 void becomes of the same of even more important than those elements forming it. [14] second/ effective dynamic digital void: the effective dynamic void is designed by freely organizing the elements of the void away from any formal constraints such as symmetry. the dynamic void gives the viewer a sense of excitement and expectation i.e. the entire void is intended to suggest motion and diversity, as the void is characterized by the flexibility that has become a requirement and a necessity to face the accelerating rate of change, that is, elements can be added or removed without affecting the cohesion of the void, and it means that the elements and their mutual relations are variable. the flexibility can be easily achieved by means of a void division or closure degree and through the presence of strength and motion in time. [22] the force is considered as the condition or the reason for every motion, especially the twists, distortions, and voids in the architectural form that provide a dynamic model based on animation and morphing. it is possible to take advantage of the software of digital moving entities to generate the form and its transformations based on the cinematic model, to exclude power and motion from the articulation of form through the mechanisms and techniques of visualization and the use of options and full menus of motion-based modeling techniques such as keyframe, key form, kinematics, inverse kinematics and forward kinematics and others. [27] as per the above, it is clear that the digital void creates the different threedimensional spatial formulas through adding the two factors of time and motion, and is considered one of the applied tools of virtual reality, which makes the architectural elements more light, transparent and graceful, and features the outputs with the absence and fading of boundaries between the inside and outside in the digital architecture. and therefore, the importance and the role of the void have emerged in the digital architectural formation in contemporary architecture. 3.6. strategies of void formation in the digital architecture interfaces: form generation strategies rely on the structure of the rules governing the form generation to allow the architect to explore meaningful bodies within more complex engineering formats that depend on the hidden capabilities and commands of digital software. [28] the digital generational approach is characterized by providing mathematical techniques for formal generation processes, in which the designer interacts with complex mechanisms that deal with the emergence of forms derived from rules, principles, and generative relations. bodies and forms are the result of pre-formed and preformed generation processes, providing control and options for the designer to choose solutions. often these processes are based on evolutionary rules and principles of natural or engineering generation. both approaches may be combined in some formation models to produce complex models which combine them both. [29] first/ void strategy as a generator of the design: the design according to "ching" is a deliberate act or intended attempt that starts from recording the problematic properties and studying their content since the nature of the solution depends on how the architect sees the problem. [4] according to “wong,”, the design is a purposeful visual formation process, which means it has a utilitarian purpose and good design is the best possible visual expression for the essence of “something”, whether it is a message or an output, and to complete this achievement efficiently, the designer must search for the best possible method to form, design, distribute, use, or link this “thing” to the surrounding environment, so the design is not only expressive but rather functional. [30] from the definition of design, it is possible to conclude the location of the void in the process, starting from the process of analyzing the problem by the void, which will lead to finding the appropriate void solution, as void is the generator of the solution proposed by the architect for the design problem. [14] the void which link the architectural work and collect the rest of the elements is often the one which evaluates the architectural work, i.e. gives it an architectural value, since the architectural work is evaluated through it. it carries the message of the architect which wants to communicate through design, and it also gives a character to the building, as it is the title or identity of the building as a whole, and that’s why this void is considered important. we cannot be certain that such a void exists in all buildings, but looking at the distinctive and valuable architectural works, we must find that generative void, and its function and location of the designs differ from one work to another as per the calculation of the architect vision and the dominant intellectual concept of his time. [14] second/ void strategy as an architectural formation unit: the void is the essence of the architectural work and a major component in the formation. it is not just a result but the starting point of the design process. [14] void is a concept that is perceived in large dimensions such as “nothingness” or “infinity”. an architectural void is a concept viewed based on “human scale,” and it has architectural characteristics [7] moreover, avoid is a unit of formation which participates in the design of work and becomes the main generator of the void relations between the other formation units. the formation unit in the architectural design is a void unit and consists of elements that form the boundaries of this void. [14] the void itself is a flexible element and this element is used as a method of void formation, and the outside form of the building includes the following variables: (boundaries, motion, construction system, envelope, type of construction, construction process, energy, environmental control and general perception). form is one of the variables of the design problem, and it is the variable that is controlled by the designer, and we must remember that solutions to design problems are an agreement between need, environment, and form, in addition to the costs. [31] third/ void strategy as a mechanism for forming the interfaces: mass and void in are among the most important formation elements in the work, followed by the motion and color, then balance and rhythm, and diversity in forms and sizes of the formative components of the work, which gives the void model formative, expressive and aesthetic values that can be felt and perceived by the viewer. [32] the void specifying elements and what is contained within are not a plate within a frame but rather a field that has a variable balance force, and these forces grow when the format of the boundary is adequate or go with one axis instead of being independent. the human being does not need to accurately record all the elements and parts to form an embodied idea of the void. [22] the void which lies within the outer body of the mass is not just a part of the cosmic void but rather a substance itself, in the sense that it is a structural part of the form which can connect the parts of the work to each other as if it were a connecting force like any other solid that enters in the formation of work. it is the void that specifies the form, properties, and dimensions of the form. [15] the model today includes many elements such as the identity of the designer, ideas, and any image or concept that he wants to show, in addition to design decisions and functional requirements. in the process of digital formation, different methods can be followed to form the model, one of them is that the designer defines a concept and designs the surrounding model based on it, so the model reflects a specific idea or symbol in the mind of the designer. basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 115 [7] the main way to solve the design problem begins with analyzing of the concepts related to the problem, and one of the most important steps that must be taken is visualization, where the thought refers to a specific concept, which is an important means that gives way to think and then to design. [7] some designers create the model using voids, thus "the void" appears as a concept that has priority in the main idea. it can be said that this method can be described as "a concept using design " or "conceptual design" where the thought comes before the form. the most important point is to ideally reflect the concept which is needed to be emphasized. during the conceptual design process, "void" is one of the prominent elements in the formation of the model. when designing forms with voids, designers express the concept that they want to reflect through the use of "the void", which generates the so-called void configurations. [7] the spatial three-dimensional form is known as the three-dimensional body, and is present in the space of the void, and it is characterized by mutual interactive relations with all its types such as the penetrating, surrounding and permeable voids. the void is considered one of the form types, as it is not something different from form, but an ethereal form in which motion is easy, and the concept of the void has evolved to go beyond being an intangible field in which forms are perceived to be considered an element of the same importance as the form. [32] as per the above, it became clear that digital technologies and the development of materials have contributed to the possibility of making the architectural void one of the mechanisms which create the void formation in the interfaces. furthermore, we find that there is an emphasis on the aesthetic role of void formations in enriching the creative and expressive values of the contemporary sectors and different types of voids in the interfaces of contemporary outputs, including the following: 1. the penetrating void: it is the void that penetrates the form and extends beyond it, so appears what is behind, and this type of void is called the absolute or endless void, which its end cannot be tracked by the eye, and allows the passage of light through it, and reduces the weight of the masses and gives new dimensions to the form and it works within the third dimension. [15] 2. the formed void: it adopts the mass as a determinant and creator for it, considering the void as a result of the architectural design. or the design starts from the void as a basic formation unit emphasizing on showing the void and hiding the structure. 3. the structured void: it consists of the formation of the structural structure, where the basic structural system of the building exists, or the structural system is more visually controlling in the building. [21] the innovation and creativity in determining the form of the structural formation, whether it is a separate or continuous construction terms, gives flexibility in the design idea and gives creativity in the formation and consistency of the masses that make up the output. [19] 4. the surrounding void: the void which exists within the external body of the mass is not just a part of the cosmic void but rather a substance itself, which means it is a structural part of the form that has the ability to connect parts of the work to each other as if it was a connecting force like any other solid that enters in the formation of that work, which is the void that determines the appearance of the form as well as its properties and dimensions. [15] 5. the four dimensional void: the four-dimensional void is a highly visualized manipulation of forms that gives the feeling of time distance. [15] 6. the creative void: the concept of the creative void refers to ignoring the void of the spatial environment in which the elements exist, and creating another void, so we a kind of conflict occurs with the nature of the spatial natural environment of the elements. [33] from the above, it becomes clear that the role of the void as a mechanism in forming interfaces is through the manipulation of solid forms and bodies in a free or formal way, and there is more than that behind this formation, as this process came not for form or aesthetic purposes only, but rather to achieve a specific goal or need. 3.7. mechanisms of void formation in the interfaces of digital architecture: architecture is a two-component formation between masses and voids, and each element has its own visual characteristics of the final formation. the architectural formations also reflect the principles controlling the relation between its elements, which are considered the basis for this formation. [9] among the most important mechanisms for finding the architectural form in the outputs of contemporary digital architecture are: 1. the superposition mechanism between architecture and computer. 2. the reduction mechanism in the reference or the elements or data entered using the digital technology. 3. the abstraction mechanism which contradicts the traditional forms of architecture. 4. the interpretation mechanism using sculptural and ambiguous forms to express the designer's thought in designing and communicating with the recipient through multiple interpretations. 5. the amplification mechanism on the scale by exaggerating in the creation of extreme forms to produce works similar to the memorial text. 6. the communication mechanism between the inside and the outside to achieve the characteristic of transparency in design work. 7. the addition mechanism, i.e. adding elements or shapes with the aim of increasing the expressive strength of the building. [34] 8. the deletion mechanism for an object that is been disintegrated into its engineering elements and provided through a simple form to create a relation between the mass and the void. the architect may interfere in the deletion of the projection, the interface, or an architectural form to create a contradiction between the positive mass and the negative void resulting from the deletion. in the projection of the arabian building, a middle or side part of the mass is deleted to produce an interior yard to enjoy the sky through it, unlike its other beneficial advantages. in the interfaces, parts of them are emptied into open terraces, as in the national bank of saudi arabia in jeddah. [9] figure 3 design with deletion the national bank in jeddah [9] 9. the deletion and addition together, i.e. forming one mass by deleting some parts of it, and adding complementary masses over it or adjacent to it. this mechanism is frequent in islamic architecture 116 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 to create a unified mass formation without tending to the single simplification. addition and deletion which can also be called negative and positive, give a contradiction in formal treatments, and this treatment has become a distinguishing feature of contemporary architectural form by combining the two opposites, and addition and deletion may be intertwined. [9] as for the mechanisms of finding the digital structures, they include flexible wrapping, bending and adopting innovative structural systems through reorganizing the structure in a new method and mechanism of penetrating, fragmentation, transformation, separation, structural synergy, employing the laws of nature, playing with tracks through the mechanism of manipulating the relation between the elements that make up the structure, or manipulating the structure and changing it, or adopting structural lightness depending on the nature of the material used. [35] according to the above, t turns out that with the increase in the ability of material and construction systems technology or digital technologies, the lightness and transparency of the construction and architectural elements increase, and some elements become able to change their characteristics to achieve technical and technological goals. so the development of building materials in contemporary architecture, in addition to many inventions has given new horizons for the architectural ideas as some new architectural materials, such as steel, aluminum, and titanium, with their advanced properties and great flexibility, have helped in covering spaces and surfaces of various formations and areas. 3.8. features and characteristics of the spatial structure in the interfaces: the quality of the form lies in its organization, so the model is produced through the possibility of achieving large voids with less support so the aesthetic value of the formation of the output depends on the continuity of the relation between the inside and outside and is generated through the balance of structural components, and by relying on several factors to achieve continuity through the continuity between the outside and inside and the continuity of light and shade. [36] the change in the spatial formation was through its representation in a twodimensional dot matrix (the projection of void or formation), as it was a regular formation from one of the basic forms (square circle triangle), changed to regular but less central forms of representation and then non central formations followed by spatial formation with two different spatial grids so that the representation becomes partially or completely irregular, up to the fragmented spatial formation which characterize the void, composition and design of the architecture of the last century from the middle to the present. [20] all these factors, building materials, and contemporary construction methods have affected the features and characteristics of the architectural void, and therefore affected the characteristics of the output. the most important characteristics of the resulting form of the void formation are the following: (symbolism and abstraction in the digital void formation of the interfaces, the absurdity in the digital void formation of the interfaces, the visual anxiety in the digital void formation of the interfaces, the dynamic formation in the interfaces of contemporary digital architecture, solid and void and interstice). 3.9. the digital architectural void as a needs achiever: scientists classify human needs according to a pyramid called the pyramid of needs, or what is known as the maslow pyramid. it divides these needs into ranks according to their importance to humans, and architecture comes to meet higher needs more than those essential. [5] the nature of these needs and how the architectural void will handle them, will be addressed. if the adoption of the void as a generator of the design or as an architectural formation unit in the outputs of contemporary architecture did not come without a reason, it came to achieve an objective or specific need. there is a diversity in the use of the void which forms the interfaces, according to the different methods of formation and the need that it achieves, as "the form and the void are complementary to each other to achieve a specific job or need". scheme 1 integration between shape and space to achieve a functional need (prepared by the researchers) first/ the void as a symbolic and aesthetic need: the void here is being formed to express a specific idea and highlight aesthetic aspects in the formation of the building. king abdullah house for culture and arts in ras al-ain region, in the jordanian capital (amman), is considered as a meeting place for the advancement of the artistic and cultural scene in the kingdom, so the design of the building was made featuring alpetra pink rocks. on her inspiration about the design of al petra rock, hadid said “petra is an ideal symbol for the successful architectural interplay between architecture and nature”. the contemporary architecture seeks to emulate nature by constructing the building through to interplay with the detailed aspects and elegance of nature. hadid sought to simulate the beauty of the pink rock, which was drifted and drilled to get along with nature, and make natural waterways to interact with the nature of the place. from this natural aesthetic element in petra, the natural passageways were designed to connect the building with the public square and connect the outside with the inside. hadid wanted to give a distinctive brightness to the building through the void which extends to the height of the building to show the interior parts, and reflect a sense of dynamism to the shape of the building from the outside. [37] second/ the void as a functional need: the function of the voids in the designs of zaha hadid is considered a special function as she used them for design purposes to link the exterior design of the building with the interior design, as she depended in her designs on the irregular or striped openings that show the light from the inside in a way connected to the external shape of the building, such as buildings with full glass interfaces to enrich the inside of void with the different natural lighting effects and the associated thermal effects of the space . in the cotaimacau, a tower and hotel project, designed by the architect zaha hadid, which was constructed of steel structures, with a mesh wrapped on the interfaces that form a series of organicallyshaped voids. the exposed exoskeleton of the tower enhances the dynamics of the design, and the structure forms a void at the front of the building and encircles it. to achieve the creative aesthetic values. [37] (form) (space) complementary (function ) basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 117 figure 4 king abdullah house for culture in the jordanian capital figure 5 tower and hotel project in kutai – macau third/ the void as a structural need: digital technology and digital manufacturing techniques contributed to the creation of modern construction systems which are considered as a revolution on old construction systems such as geodesic domes, spatial structures, extravagant structures, inflatable structures, cable systems, metal framework structures, fabrics, and light films. they enabled the architect to show the main construction elements, whether in a void or a mass, and to use them as final elements in the building without hiding them or covering them with other materials. [38] the void was formed here to reduce the weight of the facility by removing the extra loads through the digital technologies and algorithmic design programs, and the expression of the "structural system function" that achieves flexibility in the limits of the void, and making the building a mass that defies gravity. [16] fourth/ the void as an environmental need: the void has been used to achieve a specific environmental need by providing ventilation and lighting for the facility and taking advantage of the surrounding environment to reduce the buildings ’energy consumption and integrating the building with nature and making architecture part of the natural environment. as environmental formation is achieved through several methods with the aim to take care of the energy and utilize it in buildings and the outer envelope (interfaces) by employing energy sources and sustainable materials in the formation of interfaces. among these methods, is the vertical void, which can be achieved through emptying some of the built-up areas and preparing them for agriculture. [9] the bahraini trade tower project in manama is an example of this. the formation method of energy sources has been applied in the tower through placing the turbines in the space designed between the two sides of the tower, as the buildings were designed in the form of a sail on both sides to direct the winds through the gap to provide the acceleration of winds that pass through the turbines. [9] figure 6 vertical discharge in tower buildings figure 7 the vacuum as a structural need figure 8 bahrain trade tower project 4. theoretical framework: this topic deals with the presentation of a set of previous studies to extract the terms of the main and secondary theoretical framework and its possible values, and as illustrated in the table 1. below: 118 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 table 1: it illustrates the previous literature and its main and secondary and its possible value. (source: prepared by the two researchers). s. the study title the knowledge framework most important terms. 1 (k u lo ğ lu & ş a m lıo ğ lu ) ، 2 1 0 2 it dealt with the concept of the void in architectural form, as the form, space, and voids are the basic elements in the architectural design process, and presented the features of transparency and permeability. where the voids in the architectural form are classified into two main titles through the method in which the model was created: cognitive and functional voids. cognitive voids are related to the perception and used to create different visual effects, while functional voids are created to meet specific needs and desires. the study further classified the cognitive voids into three sub-titles: (conceptual, perceptual/visual, sculptural/memorial), and showed that the perceptual voids are associated with the transparency. while the visual voids are related to permeability. void types transparency permeability adoption of digitalization spatial formation deletion reduction void as functional need 2 k h a lil s tu d y 2 0 1 2 the study emphasized the role of digital technologies and technological development at the design and implementation levels. it led to the emergence of new formation rules in architecture called (digital formation rules), which affected the architectural output, so its transparency and dynamism increased in the light of these developments and the lack of weights of construction materials used for the ability to simulate them. transparency dynamic output uniqueness abandon the standardization 3 a l-h a y b a s tu d y 2 0 1 3 as a result of the state of architectural creativity presented by contemporary digital technology in the fields of terms for the architectural formation, such as the orientation towards the production of (deconstructive) architecture, (basic geometric voids) and others. the innovative treatments such as deconstructing, reconstructing, overlapping, and shattering these basic geometrical voids with the aim of achieving various purposes and goals which range from activating the building’s functional efficiency or raising the efficiency of its climate and environmental treatments. absurdity and chaos visual anxiety deconstruction and reconstruction overlap and shattering spatial structure digital formation 4 a l-k a n a w a ti s tu d y 2 0 1 5 the study emphasized that void is the generator of volumetric and functional formation relations, and therefore it is the beginning of the proposed void solution to the design problem. the void is an architectural formation unit and is the most important unit in formation, considering it as an organizer of the relations of other units and thus a generator of the design. the void acts as the organizer of the linking relations between other elements in the design. the void acts as a functional need, and it acts as the organizer of the formal linking relations between the elements, or as an aesthetic need, thus serving as a framework for the urban scene behind it. void strategy as an architectural formation unit. (void/solid) (absent-present) the void as a functional or symbolic need. 5 (s a m l io g l u ) s tu d y 2 0 1 6 the study covered the analysis of the effect of the void in space, in terms of the circumference of the void and the things surrounding it. the effect and importance of the void on the architectural design as well as the structural, functional and environmental effects of the resulting voids in the architectural (forms/voids) were emphasized and explained at three levels depending on the form and function: the effect of the void on the form.  the effect of the void one the interior space.  the effect of the void on the exterior/urban space. permeability. interactive. unit. complexity and contradiction. sculpture. deletion and addition. 6 s tu d y o f a l-m a jd i a n d o th e r s 2 0 1 8 the study gave a clear conception of the expressive relation between the external formation and the internal void and its effect on the recipient, and studied the intellectual approaches to the relation between the external formation and the internal void at the philosophical and design levels. the study also showed that employing the principle of integration in architecture requires an expressive relation between form and void that confirms this intellectual compatibility and achieves the visual enjoyment for the recipient. void morphology. static and dynamic voids. mass and void. mechanisms of integration or contradiction based on the foregoing, the terms of the main and secondary theoretical framework and the possible values can be clarified as they were extracted from the knowledge framework and previous literature, as shown in the table 2.: table 2: the terms of the main and secondary theoretical framework and the possible values. (source: prepared by the two researchers) main terms sub-term possible variables and values digital void formation strategies void strategies as a design generator computer generation (algorithm engineering) digital modeling (self-improvement) simulation synchronization (time as a fourth element of the void) void strategy as a mechanism for forming interfacing void formation manipulation reduction void strategy as an architectural formation unit hide and show deletion (hiding some parts of the mass) general mechanisms for forming a void in the interfacing binaries (solid/ void) deconstruction and reconstruction (mikano) sculpture penetration (void penetrates the mass) breaking-in (void breaks into the mass) free separation (mass separating from earth) displacement void characteris tics in digital output void as needs achiever the void as a symbolic and aesthetic need the void as structural need the void as functional need the void as environmental need features of digital spatial structure features intended by the designer interactions between the structure and nature visual penetration porosity interstitial transparency and permeability structure dynamics structure flexibility dynamic abstraction (non-correlation) features intended by the recipient interactions between the structure and user absurdity and chaos visual anxiety symbolism and abstraction enjoyment and excitement brilliance, uniqueness and synchronization artistic sculptural properties basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 119 4.1. the application on the samples: in order to verify the research hypothesis which states “adopting the digital void formation strategy to combine digital formation mechanisms which are used to create a void formation that meets the needs in contemporary architecture interfaces". the application will be performed on architectural samples of a different nature with the aim to find a large area to show the effect of void on the formation of interfaces which will eventually show the characteristics of digital spatial structure. samples were selected within spatial contexts (global, arab and local) to clarify the possibility of the impact on them despite the change of times. 4.1.1. china central television project cctv the project china central television sample code location china/ beijing /2012 a design rem koolhaas & ole scheeren oma company project description it was designed with 473 m2 of floor space. the building is a symbol for china and a potential for digital design, as the need of the void design was aesthetic and symbolic. the conceptual process was based on a threedimensional concept of architecture. it was designed with 473 m2 of floor space. the building is a symbol for china and a potential for digital design, as the need of the void design was aesthetic and symbolic. the conceptual process was based on a three-dimensional concept of architecture. for in order to understand the distortion of its forms, we need to look at it in three dimensions at the same time, that is, to introduce the dimension of motion, by using modeling with a computer program, where the classic rules of formation are destroyed, and new digital rules of formation are adopted to bring architecture closer to sculpture. [39] the construction of this structural building is a challenge because it is located in a seismic zone, so the void here was generated by the design to achieve a structural need that includes the durability necessary to resist potential seismic activity, by adopting advanced non-linear simulation. [40] a "diagrid" system of a network of triangular steel tubes was adopted for the external structure, to give a structure that resists gravity and side forces, by adopting the manipulation mechanism on the force paths, so that the interface itself becomes an impressive architectural appearance of the structure. the void here is structural, that is, emerging from the structure. [39] the building design depends on achieving integration in the design process architecturally, structurally and mechanically. 4.1.2. opus tower in dubai the project opus tower sample code location united arab emirates 2019 b design zaha hadid, patrik schumacher and christos passas omniyat company project description the opus building in dubai is an iconic architecture in the middle east and the world, designed with a space of (84345.0 m2) with the latest international models to serve as a cityscape of the middle east, taking the form of the cube. the cube is then ‘carved’, creating a central void that is an important volume within the building, providing views to the exterior from the center of the building. the free-formed fluidity of this eight-story void contrasts with the precise orthogonal geometry of the surrounding cube. the building is comprised of two structures that are linked by a height of 21 floors, with a hidden base that makes it appear floating above the surface of the earth, and with a night view different from the day, as it appears during the day as shinning full cube due to the sunlight. at night, the lights fill the voids, as its glass interface absorbs light and shines a wonderful artificial lighting. the design shows the brilliant innovative quality of zaha hadid's work, expressing a sense of sculpture that reinvents the balance between solid and void, dark and transparent, inside and outside. so organic void is considered as the focal point of the design, which contrasts beautifully with the surrounding architecture, while presenting unexpected views for outside from the center of the building, giving the building a high aesthetic and interactivity with the outside environment. [40] 4.1.3. the project of iraqi general secretariat of the council of ministers the project iraqi general secretariat of the council of ministers sample code location iraq/ baghdad / 2010 c design manhal al-haboobi – cap office project description a contemporary architectural work which represents the mesopotamian civilization. the project is unique and special. the building space is 178,000 m2 with a height of 12 floors. the form consists of two main parts: the “seal” building which is topped by a tower, and the “ring building” which forms the base of the building with four main entrances to the project. the building is characterized by achieving sustainability with the latest technologies. form generation was processed like the biological process in which the organism develops physically after birth or hatching. [41] the formal reference, represented by meanings and symbols, was chosen to discover a specific symbol to the civilization of iraq, to gain dimensions represented by the infinite motion of the structure of this two-dimensional symbol and transform it into a three-dimensional composition using the method of formal impossibility, in addition to employing contemporary digital technologies in the design, production, and modeling of the project. [42] making a slight curve in the building implies dynamism, continuity, and an expression of infinity. as for the void formation mechanism, it was applied through the contrast in the relation between (solid / void). [40] https://www.google.com/search?sa=x&biw=1366&bih=625&sxsrf=alekk027_jiej1p2zmv1czdsrbj9crzn2q:1585992527109&q=rem+koolhaas&stick=h4siaaaaaaaaaopge-luz9u3mc7jscxt4gaxzdiljlxus5ot9jnkizpzuoul4yz4_iluossszpw8q7t80ryu1kjfrdxbqbkk3vn5ormjicu7wbkb2todgliaaaa&ved=2ahukewici8fjus7oahvhpcakhrgrbjaqmxmoataoegqidrad 120 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 table 3: applying the terms on the samples (a, b, c), (source: prepared by the two researchers) m a in t e r m s s u b -te r m possible variables and values achieved values in the projects v a lu e s t o ta l the ratio of possi ble valu es discus sing the results a b c d ig ita l v o id f o rm a tio n s tra te g ie s v o id stra te g ie s a s a d e sig n g e n e ra to r computer generatio n (algorith m engineeri ng) 0 0 0 0 0% not achiev ed digital modeling , selfimprovem ent 1 1 0 2 66% partiall y achiev ed simulatio n 0 0 1 1 33% poorly achiev ed synchroni zation (time as a fourth element of the void) 0 0 1 1 33% poorly achiev ed total of achieved values of each sample 1 1 2 4 33% the achieved percentage of each sample 25 % 25 % 50 % v o id stra te g y a s a m e c h a n ism fo r fo rm in g in te rfa c in g void formation 1 1 1 3 100 % highly achiev ed manipulat ion 1 1 0 2 66% partiall y achiev ed reduction 1 1 1 3 100 % highly achiev ed total of achieved values of each sample 3 3 2 8 88% the achieved percentage of each sample 10 0 10 0 66 void strategy as an architec tural formati on unit hide and show 0 0 1 1 33% poorly achiev ed deletion 1 1 1 3 100 highly (hiding some parts of the mass) % achiev ed total of achieved values of each sample 1 1 2 4 66% the achieved percentage of each sample 50 % 50 % 10 % g e n e ra l m e c h a n ism s fo r fo rm in g a v o id in th e in te rfa c in g binaries (solid/ void) 1 1 1 3 100 % highly achiev ed deconstru ction and reconstruc tion (mikano) 1 1 0 2 66% partiall y achiev ed sculpture 1 1 1 3 100 % highly achiev ed penetratio n (void penetrates the mass) 0 0 1 1 33% poorly achiev ed breakingin (void breaks into the mass) 1 0 0 1 33% poorly achiev ed free separation (mass separating from earth) 0 0 1 1 33% poorly achiev ed displace ment 0 0 1 1 33% poorly achiev ed total of achieved values of each sample 4 3 5 1 2 56% the achieved percentage of each sample 57 % 42 % 71 % v o id c h a ra c te ristic s in d ig ita l o u tp u t v o id a s n e e d s a c h ie v e r the void as a symbolic and aesthetic need 1 1 1 3 100 % highly achiev ed the void as structural need 1 1 0 2 66% partiall y achiev ed the void as functional need 0 1 0 1 33% poorly achiev ed basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 121 the void as environm ental need 0 1 1 2 66% partiall y achiev ed total of achieved values of each sample 2 4 2 8 66% the achieved percentage of each sample 50 % 10 0 50 % f e a tu re s o f d ig ita l sp a tia l stru c tu re f e a tu re s in te n d e d b y th e d e sig n e r interactio ns between the structure and nature 0 1 0 1 33% poorly achiev ed visual penetratio n 1 1 1 2 66% partiall y achiev ed porosity 0 1 0 1 33% poorly achiev ed interstitial ity 1 1 1 3 100 % highly achiev ed transpare ncy and permeabil ity 1 1 1 3 100 % highly achiev ed structure dynamics 1 1 0 2 66% partiall y achiev ed structure flexibility 0 0 0 0 0% not achiev ed dynamic abstractio n (noncorrelatio n) 1 1 1 3 100 % highly achiev ed total of achieved values of each sample 5 7 4 1 5 62% the achieved percentage of each sample 62 % 87 % 50 % f e a tu re s in te n d e d b y th e re c ip ie n t interactio ns between the structure and user 1 0 0 1 33% poorly achiev ed absurdity and chaos 0 1 0 1 33% poorly achiev ed visual anxiety 0 1 0 1 33% poorly achiev ed symbolis m and abstractio n 1 1 0 2 66% partiall y achiev ed enjoymen t and excitemen t 0 1 1 2 66% partiall y achiev ed brilliance, uniquenes s and synchroni zation 1 1 1 3 100 % highly achiev ed artistic sculptural properties 1 1 1 3 100 % highly achiev ed total of achieved values of each sample 4 6 3 1 3 61% the achieved percentage of each sample 57 % 85 % 42 % 4.2. analyzing and discussing the results: the paragraph explains the most important results of the application on the selected samples: 4.2.1. the results related to the term of digital void formation strategies: the results of void formation strategies in digital architecture interfaces revealed that (void strategy as a mechanism for forming interfaces) achieved the highest percentage within the four main strategies by (88%) compared to the lowest percentage of (void strategy as a design generator) which is (33%). while the strategy of (void strategy as an architectural formation unit) achieved (66%), followed by (the general mechanisms for forming interfaces in digital architecture) by (56%), as shown in the chart (1-2). first: void strategy as a mechanism for forming interfaces: which is classified into three main mechanisms (void formation, reduction, and manipulation). both of (void mechanism) and (reduction mechanism) achieved the highest percentage of (100%), while (manipulation mechanism) achieved (66). as for the single results of each project, we notice a difference in the achieved results, as results showed similar percentages in the results of the selected samples (a, b) by achieving a percentage of (100%), followed by the sample (c) with a percentage of (66) %). therefore, we conclude that the samples (a, b) are the most creative as they included the use of the three mechanisms (void formation, reduction, and manipulation) to achieve a unique and creative spatial structure. second: void strategy as an architectural formation unit: it is classified into two main mechanisms (hide, show, and deletion). as the term (deletion) achieved the highest percentage of (100%) compared to (33%) of (hide and show). as for the single results of each project, we notice similar results for the selected samples (a, b) by achieving a percentage of (50) %), compared to (100%) for the sample (c). therefore, it is clear that the sample (c) relied on the void strategy as a first-order architectural formation unit. third: general mechanisms for forming a void in the interfaces: they are classified into several main mechanisms of binaries (solid/void), deconstruction and reconstruction (mikano), sculpture and penetration (void penetrates the mass), breaking-in (void breaks into mass), free separation (mass separating from earth) and displacement. 122 basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2020) 109–124 the binaries (solid/void) and sculpture achieved the highest percentage (100%), while deconstruction and reconstruction (mikano) achieved a percentage of (66%). whereas penetration (void penetrates the mass), breaking-in (void breaks into mass), free separation (mass separating from earth), and displacement achieved (33%) for each. as for the single results of each project, we notice a difference in the achieved results, as the results showed that the highest percentage of (71%) of the sample (c) was achieved, followed by sample (a) with a percentage of 57%, while sample (b) achieved (42) %). fourth: the void strategy as a generator for the general design: it is classified into several sub-terms which are computer generation (algorithm engineering), digital modeling (self-improvement), simulation, and synchronization. the results showed that digital modeling (self-improvement) achieved the highest percentage of (66%), compared to (0%) for (computer generation). while (simulation and synchronization) achieved a percentage of (33%) for each. as for the single results of each project, we notice a difference in the achieved results, as the results showed that the highest percentage of (50%) was achieved for sample (c), followed by samples (a, b) with a percentage of (25%). 4.2.2. the results related to the term of void characteristics in the digital output: the feature of void as a needs achiever in the interfaces of digital architecture revealed the superiority of (void as a symbolic and aesthetic need) by achieving the highest percentage (100%) compared to the lowest percentage of (void as a functional need) which is (33%), while both of (void as structural need) and (void as environmental need) achieved (66%) for each, as shown in the chart (1-3). as for the single result of each project, we notice a difference in the achieved results. as the results showed that the highest percentage (100%) of the sample (b) was achieved, while the samples (a, c) achieved a percentage of (50%) for each, which indicates that sample (b) formed the void in the interface to achieve the functional, aesthetic, structural and environmental needs. 4.2.3. the results related to the term of features of digital spatial structure: the results showed the superiority of (interstitially, transparency, permeability, dynamic abstraction, brilliance, uniqueness and sculptural properties) by achieving the highest percentage (100%) compared to (0%) for the term (structure flexibility), while (visual penetration, structure dynamics, symbolism, abstraction and enjoyment and excitement) achieved a percentage of (66%) for each. the values of each of (the interaction between structure and nature, porosity, and the interaction between structure and the user, absurdity, chaos, and visual anxiety) were similar in achieving (33%) for each. as for the single result of each project, we notice a difference in the achieved results, as the results showed that the highest percentage (85%) of the sample (b) was achieved, while the sample (a) achieved a percentage of (57%), followed by the sample (c) with (42%). this indicates that the sample (b) was distinguished by achieving most of the features that the void gives to the output, such as the interaction between the structure and nature, visual penetration, porosity, interstitiality, transparency, permeability, and structure dynamics in addition to brilliance, uniqueness, synchronization and other sculptural and artistic properties. 88% 66% 56% 33% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90 % 100% vacu um strategy as a mechanism fo r for mi ng inter faces space strategy as an archi tectu ral fo rmatio n unit general mechanis ms f or fo rming a vacu um in th e facade space strategy as a generator of des ign scheme 2: ratios achieved strategies void forming digital (prepared by the researchers) a symbolic and an environmental 100% 66% 66% 0% 20% 40% 60% 80% 100% 120% scheme 3: ratios achieved strategies of the void property as a needs investigator (prepared by the researchers) 5. conclusions: 5.1. theoretical part conclusions:  the idea of the emergence of an architectural void within the formation of the mass started in the outputs of the modern architecture, as it began to reduce the elements and generate unexplained voids as a result of reduction and simplicity only. as for the deconstruction architecture, the emergence of an architectural void was a clear and distinctive through the adoption of the deconstruction and the non-correlation that led to the formation of voids which directly affected the body of the building.  the disappearance of boundaries between the exterior and interior over time led to the use of void in the formation of the building's outer mass (at the three-dimensional level), and sometimes the formation of the mass is based on that void which is called (designgenerating void) and the name of the structure which is created by void is (spatial structure) as its formation depended on "geometry" and its methods of formation.  the perception of the void concept has changed by acquiring new properties such as flexibility and dynamism due to the technologies provided by digitization, as void is connected to time by integrating the inside and outside and adding time as a fourth dimension of architectural output.  it is necessary to rely on the capabilities provided by technology as a basic form generator to look for strength and durability in order to create void configurations that are consistent with the era of the digital revolution and characterized by dynamism, abstraction and high symbolism. basim hassan almajidi and shams a. ameer /al-qadisiyah journal for engineering sciences 13 (2019) 109–124 123  the various forms of the three-dimensional void served as a regulator of formal interrelations in the design process, i.e. to connect and organize the relation between voids and form elements. therefore, this process is affected by the nature of the geometrical form of the void, and each form has properties distinguishing it and controlling the relation between the elements, so the form of the void affects the interrelation between void and other design elements.  formulas of creating the architectural void included several forms through the relation between the binaries (solid-void), (absentpresent), (positive-negative) and (hide-show), as the void appears as a spatial output after withdrawal or removal or the deletion of the solid mass, or a vacant space for form, or absence of the form, or it appears as a spatial interference in the variants, such as the convergence zone between two forms, so it is defined as convergence or collision between two forms, where a void or middle space is created by the overlapping of two solid elements. 5.2. the practical part conclusions  the strategies for void creation differentiate in the interfaces of digital architecture according to the idea of the project or the purpose of finding the void for in the interface. to achieve this, architects tend to integrate more than one strategy to reach a distinctive void formation that reflects the high sensory and visual effects and achieves the formal and functional needs for which it was designed. the results showed a primary focus on the void strategy as a mechanism for forming interfaces of digital architecture for the purpose of adding unique aesthetic features and improving the formative properties of the digital void according to the requirements of each project.  the void is formed to achieve several needs such as (symbolic and aesthetic need, structural need, functional need, and environmental need). the application result showed more than one need was achieved in the same project, since all projects achieved the symbolic and aesthetic need to give symbolism and multiplicity of meaning to the outputs of contemporary architecture and make the output as an attracting force to building and a framework for the urban scene which follows, in addition to other needs.  the void achieves the structural need in the architectural models by reducing the building weight and achieving balance and stability, and generating economical and highly efficient outputs.  the formation of void in the interfaces of digital architecture enrich it with features such as the 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[42] al-morshedy, siraj jabbar kazim, “the impact of digital technology on the contemporary architectural form,” master thesis, university of technology, department of architecture, 2017. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٠ optimum power generation for iraqi super high voltage system dr. samir s. mustafa kirkuk technical institute abstract iraqi super grid power system consists of six generating power plants : baji, sad al-mosul, haditha, mussayab, nasiriya and hartha. a matlab5.3 package has been used to calculate the optimum generation of the system generators which gives minimum losses in comparison with the total losses according to the same data which were recorded in national control center. the losses reduction became 30.96% . gradient method has been employed for the solution of optimal power flow. the partial derivative of active and reactive losses with respect to injected power were used as an indicator on optimum power generation. keywordsoptimum, power generation. �رة ,/@3(� أ �de أ &�!: �� أ ��اق�� ��)fأ � أ �3 � �ون ()'&%. د �� ��,� كآ�آ3/ ا ,�0� ا ��/� أ �56� �< ��اق *���ن � ?l �4-"ت *� � أ� !"# � : ������ أ &%$ أg<f ، ax�� .أ �"�9�x وأ 8"ر=� ، أ ��b9�� ، n<d ، ?� أ �%�f ه�"s q�")�f ام�g�?ا l*٥.٣matlab �f)ر"i� �f����� � أf� �!"df� af/أ �f-�� *� أ �f-4"ت وا 5fي 9� �< �* abأ� ; وا ��ax إ � ��آ�f أ df>-�ة أ � �f<�o�l&f#g)" ا dfg"!� أ ��>�fi�f �fار �j أ dg"!� أf� ��gdf� *lf % . p#) ns��f �f�d4�٣٠.٩٦ أ '>"("ت أ rz4-"ت أ�� � ا� �< �� � ا� �<�b� j4.�ل أ� �f وا ��#"���f .ا?��gام �i9�o ا ��رج "�# dfg"!� ا �fiرة ا �f!�g *l ا?��gام أi�(j"ق ا �)�i4� >�ه"(d'� إ ; ا �iرة ا�* ����>"ت آ�v)� ��; ا�ab /�رة ��9 � j<�s ا�. introduction many different mathematical techniques have been employed for the solution of optimal power flow. the majority of the techniques in the references ( selman2005), (antonio2002), (quek2002), (pjiac2003), (kristiansen2002) and (stevenson1985) use one of the following methods: 1lambda iteration method. 2gradient method. 3newton’s method. 4linear programming method. 5interior point method. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠١ optimal power flow (opf) has been widely used in planning and real-time operation of power systems for active and reactive power dispatch to minimize generation costs and system losses and improve voltage profiles. the primary goal of opf is to minimize the costs of meeting the load demand for a power system while maintaining the security of the system (claudio2001). the cost associated with the power system can be attributed to the cost of generating power (megawatts) at each generator, keeping each device in the power system within its desired operation range. this will include maximum and minimum outputs for generators, maximum mva flows on transmission lines and transformers, as well as keeping system bus voltages within specified ranges. opf program is to determine the optimal operation state of a power system by optimizing a particular objective while satisfying certain specified physical and operating constraints to achieve these goals, opf will perform all the steady-state control functions of power system. these functions may include generator control and transmission system control. for generators, the opf will control generator mw outputs as well as generator voltage. optimization and security are often conflicting requirements and should be considered together. all the optimization problems can easily be transcribed into the following standard form (yong1999) and (john2003): min f )( x subject to: gi 0)( ≤x i = 1, …, ng hk(x) = 0 k = 1, …, mh where { } ℜ∈= n xxx ... 1 (design variables). f(x) the objective function. gi(x) inequality constraints. hk(x) equality constraints. we assume that only part ( gi p ) of the total net power is controllable for the purpose of optimization. the objective function can then be defined as the sum of instantaneous operating costs over all controllable power generation: f (x)=∑ i igi pc )( (1) where ci is the cost of producing pgi. the minimization of system losses is achieved by minimizing the power injected at the slack node. note that baji generator has been chosen as slack node. the minimization of the objective function f (x) can be achieved with reference to the lagrange function (l). the nonlinear power loss equation is: ploss = ∑ = n i 1 ∑ = n j 1 [ ])cos(vv2vvgij jiji 2 j 2 i δδ −−+ (2) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٢ the linearized sensitivity model relating the dependent and control variables can be obtained by linearizing the power equations around the operating state. despite the fact that any load flow techniques can be used, n-r load flow is most convenient to use to find the incremental losses. the change in power system losses, l p∆ , is related to the control variables by the following equation ( selman2005) l p∆ = m ll v p v p ∂ ∂    ∂ ∂ .. 1    ∂ ∂ ∂ ∂ ++ wm l m l q p q p .. 1                 ∆ ∆ ∆ ∆ + + wm m m q q v v 1 1 m (3) electric power systems designed with generating units that are widely scattered and interconnected by long transmission lines may suffer significant losses. the losses depend on the line resistance and currents and are usually referred to as thermal losses. while the line resistances are fixed, the currents are a complex function of the system topology and the location of generation and load. using the load data collected on 2/1/2003 in table 1 which can be obtained from the iraqi control center (afaneen2004) algorithm was applied to determine the best placement of new units in order to maximize power available and minimize losses on the system for a given load (william2002) the analysis objective is to find the partial derivatives (sensitivity) of active power loss with respect to active and reactive power injected at all buses except slack bus. [ ] [ ppsen l ∂∂= / ]qp l ∂∂ / (4) the results of sensitivity vector [ ]sen are used as an indicator to the efficiency of the system to reduce losses in case of installing generation units or shunt capacitors at these buses. the following matrix [d] is the partial derivative of real losses with respect to voltage magnitude at load buses and voltage angles at all buses except slack bus (samir2007). [ ]                           ∂∂ ∂∂ ∂∂ ∂∂ ∂∂ ∂∂ = ∂ ∂ = +1 3 2 3 2 / / / / / / nlloss loss loss nloss loss loss vp vp vp p p p x f d δ δ δ (5) the components of [ ]d are calculated as follows: [ ]∑ ≠ = −=∂∂ n ij j jijiijiloss vvgp 1 )sin(2/ δδδ (6) al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٣ [ ]∑ ≠ = −−=∂∂ n ij j jijiijiloss vvgvp 1 )cos(2/ δδ (7) the mathematical analysis needs also jacobian matrix [ ]jac which is used before in power flow problem, then: [ ] [ ] [ ]dsenjac t = (8) then [ ] [ ] [ ]djacsen t 1− = (9)       sen sen q p =             ∂ ∂ ∂ ∂ q p p p l l = [ ]           ∂ ∂ ∂ ∂ − v p p jac l l t δ1 (10) where psen = partial derivative of real losses with respect to real power injected at load buses. qsen = partial derivative of real losses with respect to reactive power injected at load buses. [ ]j is the jacobian matrix of newton-raphson load flow. then psen =             ∂ ∂ ∂ ∂ +1 2 nl p ploss p ploss (11) and qsen =             ∂ ∂ ∂ ∂ +1 2 nl q ploss q ploss (12) iraqi national super grid iraqi national super grid contains six generating sets of various types units, thermal and hydro turbine kinds, with different capabilities of mw and mvar generation and absorption. the load and generation of insg system on the 2 nd of january 2003 are tabulated in table 1 machines parameters and lines are tabulated in tables 2 and 3 (afaneen1998) a software package under matlab5.3 has been developed to perform electrical power system analysis on a personal computer. the software is capable of performing admittance calculations, load flow studies, optimal load flow studies of electric power systems. the sensitivity of each power plant to reduce losses with respect to power generation is calculated according to equation (10).the results were shown in tables (1-5). as shown in these figures, increasing power generation at each bus reduces system losses if sensitivity value at that bus is negative. on the other hand increases power generation at each bus increases system losses if sensitivity value is positive. the values of power generation which give minimum losses at sdm, had, msb, nsr, and hrt power plants are 250, 425, 950, 700, and 450 mw respectively. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٤ notice that increasing power generation at each bus reduce system losses if sensitivity value at that bus is negative, and increase system losses if sensitivity is positive. system power losses with respect to sensitivity of each power plant shown in figures 6, 7, 8 & 9. calculations of optimal power generation optimal power generation for all generation plants can be obtained by increasing real power of each generator with small amounts at the same time, as shown in figure 11. increasing active power for each generator is stopped when sensitivity at that generator bus becomes zero or positive. the over all process continues until the sensitivities for all buses become zero or positive. the procedure is done using the package under matlab. the results show that optimum power generations give minimum losses equal to 25.95mw where shown in table 4. also the results show that total losses with ordinary generation is equal to 37.592mw using the data of ordinary generation and loads on the 2 nd of jan. 2003. optimal losses reduction = ( losses with ordinary pg – losses with optimum pg) / losses with ordinary pg x 100% = 37.592-25.95 / 37.592 = 30.96 % conclusions using sensitivity analyzing gives us a good indicator about the buses which are sensitive to reduce system total losses .increasing power generation at each generation plant reduces system losses if sensitivity value at that bus is negative. on the other hand increasing power generation at each bus increases system losses if sensitivity value is positive. the results show us that optimum generation in the generation plants give minimum total losses in the iraqi national super grid without exceeding the constrains of voltages, active and reactive power, as shown in table 5. references • afaneen a. abood automated mapping facilities management geographic information system of a power system, m. sc. thesis, university of technology, baghdad, 1998. • afaneen a. abood, implementation of geographic information system (gis) in real-time transient stability, ph.d. thesis, university of technology, baghdad, 2004. • antonio j. and maria j., “optimal power flow algorithm based on tabu search for meshed distribution networks”, www.pscco2.org, 2002. • claudio c., “comparison of voltage security constrained optimal power flow techniques”, proc. ieee-pes summer meeting vancouver, bc, july 2001. • etienne j., “a reduced gradient method with variable base using second order information, applied to the constrained and optimal power flow”, www.system.seurope.be/pdf, 2000. • john r., “engineering design optimization”, www.me.uprm.edu/vgoyal/inme 4058, 2003. • kristiansen t., “utilizing mat power in optimal power flow”, www.ksg.haward.edu, 2002. • pajic s., “sequential quadratic programming-based contingency constrained optimal power flow”, m. sc. thesis, worcester polytechnic institute, www.wpi.edu. april 2003. al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٥ • quek r., “power transfer capability assessment”, www.innovexpo.itee.uq.edu.au/ 2002. • samir s. mustafa, minimum power losses based optimal power flow iraqi national super grid and its effect on transient stability, ph.d thesis, university of technology, baghdad, 2007. • stevenson w. d., “elements of power system analysis”, mcgraw-hill book co. 4 th edition, 1985. • william r., "optimal placement of distributed generation", www.pscco2.org, 2002, usa. • yong t. and lasseter r., "opf formulation in market of retail wheeling", www.pserc.cornell.edu, 1999. table1: insg system load data generation load bus bar number bus bar name type mw mvar mw mvar 1 baj slack 570.592 100.4455 200.00 98.00 2 sdm p,v 700.00 23.2248 5.00 2.00 3 had p,v 500.00 0.8474 100.00 60.00 4 qam p,q .00 .00 60.00 40.00 5 mos p,q .00 .00 300.00 180.00 6 krk p,q .00 .00 70.00 40.00 7 bqb p,q .00 .00 150.00 80.00 8 bgw p,q .00 .00 500.00 360.00 9 bge p,q .00 .00 500.00 360.00 10 bgs p,q .00 .00 100.00 50.00 11 bgn p,q .00 .00 300.00 200.00 12 msb p,v 600.00 420.6564 120.00 70.00 13 bab p,q .00 .00 100.00 50.00 14 kut p,q .00 .00 100.00 60.00 15 kds p,q .00 .00 200.00 100.00 16 nas p,v 650.00 69.1434 100.00 54.00 17 kaz p,q .00 .00 350.00 200.00 18 hrt p,v 380.00 35.9855 38.00 22.00 19 qrn p,q .00 .00 70.00 30.00 total 3400.592 463.8716 3363 2056 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٦ table2: machine's parameters table3: insg system line data from to r (p.u) x (p.u) b (p.u) baj4 sdm4 0.00542 0.0487 1.4384 mos4 sdm4 0.00143 0.0124 0.36439 mos4 baj4 0.00399 0.03624 1.074 baj4 had4 0.00364 0.03024 0.8676 qam4 had4 0.0035 0.03 0.7413 bge4 bqb4 0.00076 0.00689 0.2043 baj4 krk4 0.00182 0.01654 0.49031 baj4 bgw4-2 0.0055 0.05004 1.4826 baj4 bgw4-1 0.00483 0.04393 1.3017 had4 bgw4 0.00483 0.04393 1.3017 bgw4 bgn4 0.00093 0.00847 0.25099 bgn4 bge4 0.00029 0.00265 0.0788 krk4 bge4 0.00481 0.04373 1.29581 bge4 bgs4 0.00105 0.00955 0.28309 bgw4 bgs4 0.00144 0.0131 0.38816 bgs4 msb4-1 0.00121 0.0102 0.30944 bgs4 msb4-2 0.00121 0.0102 0.30944 bab4 msb4-1 0.00077 0.00648 0.19666 bab4 msb4-2 0.00077 0.00648 0.19666 node name armature arg (per transient xd (per inertia constant baj4 0.0 0.0122242 132 sdm4 0.0 0.037 91.008 had4 0.0 0.04948 36.096 msb4 0.0 0.017225 104 nsr4 0.0 0.0285 99.94 hrt4 0.0 0.0508 47.5 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٧ bgs4 kut4 0.00245 0.02236 0.6625 bgs4 kds4 0.00292 0.02659 0.788 kds4 nsr4 0.00383 0.03486 1.03314 kaz4 nsr4 0.00439 0.03999 1.1849 kut4 nsr4 0.00433 0.0394 1.1674 kaz4 hrt4 0.00119 0.01083 0.32104 qrn4 hrt4 0.0013 0.01182 0.35022 qrn4 kut4 0.00628 0.05713 1.6927 table4: active power generations which give optimal losses reduction table5: limits of generation and load buses qgeneration [mvar] voltage [p.v] bus bar qmin qmax vmin vmax 1 200 200 0.95 1.05 2 257.15 433.82 0.95 1.05 3 183.68 309.87 0.95 1.05 4 0 0 0.95 1.05 5 0 0 0.95 1.05 6 0 0 0.95 1.05 7 0 0 0.95 1.05 8 0 0 0.95 1.05 9 0 0 0.95 1.05 10 0 0 0.95 1.05 11 0 0 0.95 1.05 12 220.42 371.85 0.95 1.05 generation bus number generation [mw] baj 571 sdm 250 had 350 msb 1000 nsr 500 hrt 400 al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٨ 13 0 0 0.95 1.05 14 0 0 0.95 1.05 15 0 0 0.95 1.05 16 238.77 402.83 0.95 1.05 17 0 0 0.95 1.05 18 139.6 235.5 0.95 1.05 19 0 0 0.95 1.05 figure (1): ploss vs. pinjection at bus 17 (kaz) figure (٢): ploss vs. pinjection at bus 19 (qrn) 0 20 40 60 80 100 120 140 160 180 36.7 36.8 36.9 37 37.1 37.2 37.3 37.4 37.5 37.6 plosses[mw] pinjection[mw] bus 17 max loss reduction=2.34% 0 20 40 60 80 100 120 140 160 180 200 36.8 36.9 37 37.1 37.2 37.3 37.4 37.5 37.6 37.7 37.8 37.9 38 bus 19 optimum reduction=1.71% ploss[mw] pinjection[mw] al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥٠٩ 6 7 8 9 10 11 12 13 14 15 16 17 18 19 0 5 10 15 20 25 30 35 40 max loss reduction% bus no. figure3:loss reduction for injecting real power at some buses figure4: ploss vs. qinjection for bus 4 (qam) 0 5 10 15 20 25 30 35 40 45 50 37.59 37.6 37.61 37.62 37.63 37.64 37.65 37.66 bus 4 (no loss reduction) ploss[mw] qinjection[mvar] al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٠ figure5: ploss vs. qinjection for bus 5 (mos) figure 6: relationship between sensitivity and system losses at bus 2 (mos) 0 50 100 150 200 250 300 37.35 37.4 37.45 37.5 37.55 37.6 37.65 ploss[mw] bus 5 optimum loss reduction=0.59% qinjection[mvar] 0 100 200 300 400 500 600 700 800 31 32 33 34 35 36 37 38 39 bus 2 ploss[mw] pgeneration[mw] al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١١ figure 7: relationship between sensitivity and system losses at bus 3 (had) figure 8: relationship between sensitivity and system losses at bus 12 (msb) -0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 bus 12 ploss[mw] sensitivity -0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 bus 12 ploss[mw] sensitivity al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٢ figure 9: relationship between sensitivity and system losses at bus 16 (nsr) figure10: relationship between sensitivity & system losses at hartha bus18(hrt) -0.01 -0.005 0 0.005 0.01 0.015 0.02 0.025 37 37.5 38 38.5 39 39.5 40 ploss[mw] sensitivity -0.01 -0.005 0 0.005 0.01 0.015 0.02 0.025 37 37.2 37.4 37.6 37.8 38 38.2 38.4 38.6 38.8 39 ploss[mw] sensitivity from a subroutine calculating losses using eq.٢ al-qadisiya journal for engineering sciences vol. 2 no. ٢ year 2009 ٥١٣ figure11: flow chart illustrating optimization program using sensitivity analyzing form vector       ∂ ∂ x f using eq.5 form vector       ∂ ∂ u f =       ∂ ∂ v p calculate gradient of f [ ] λ×      ∂ ∂ +      ∂ ∂ =∇ t u g u f f form vector       ∂ ∂ u g =the partial derivative of injected power calculate the sensitivity ( λ ) [ ]       =       ∂ ∂ −== − sen sen t q p sen x f jacsen * 1 λ form hessian matrix (h)which represent the second partial derivative for ploss w.r.t control variables calculate variable incremental [ ] [ ] [ ]fhu ∇×−=∆ −1 [ ] op u ε:∆ develop variables [ ] 11 ++ ∆+= kkk uuu max1min uuu k ≤≤ + to a subroutine to calculate pi&qi injection power calculate load flow and transmission line losses end k=k+1 article al-qadisiyah journal for engineering sciences 15 (2022) 018–022 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: inm.khld@atu.edu.iq (khalid m. breesem) https://doi.org/10.30772/qjes.v15i1.808 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. improvement behavior of rc beams with continuous spiral stirrups under shear thaer jasim mohammed a and khalid m. breesemb* adepartment of civil techniques, institute of technology/ baghdad, middle technical university, baghdad, iraq bmussaib technical institute, al-furat al-awsat technical university, babylon, iraq a r t i c l e i n f o article history: received 6 april 2022 received in revised form 5 june 2022 accepted 3 july 2022 keywords: spiral stirrups rc beam finite element analysis shear strength each a b s t r a c t reinforced concrete, rc beams subjected to shear failure which is the most unwanted failure mode due to speed progress is studied numerically. therefore, the effective design of beams is necessary because of the sudden failure types of these beams in shear. the minimum shear reinforcement ratio of rc beams must be provided around the longitudinal rebars. thus, the stirrups with different patterns have a significant benefit for improving the rc beam. in this paper, the performance of specimens with different spiral stirrups using ansys programs is investigated by comparing them with conventional stirrups of rc beams. one statement on the experimental results has been obtained from previous research karayannis et al. [17]. the behaviors of these experimental beams are compared with finite element analysis of the identical beams. it is found that the behaviors of the experimental beam in comparison with the behaviors of the numerical beam are slightly different. based on the fe analysis, the shear strength results demonstrated the mean accuracy and standard deviation of about 0.994 and 0.028, respectively, compared with the experimental test. furthermore, the curve determined from fe analysis is consistent with the experiment data. the results give knowledge about the importance of spiral stirrups of the beam, and the most effective method among the investigated cases. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction shear failure behavior is brittle due to the rapid breakdown of reinforced concrete beams [1]. it makes predicting the occurrence of shear failure is difficult due to low deformations. the use of stirrup correctly is necessary for buildings construction to ensure bending failure occurs before sudden shear failure. therefore, it is necessary to discover more effective stirrup reinforcement methods for shear beams. thus, stirrups with different patterns are a significant benefit [2]. the spiral reinforcement of seven small-sized rc beams enhances the ductility of the beam before shear failure occurs. mixed shear reinforcement of rc beam-column joints improved failure mechanisms and increased bearing compared to specimens with traditional stirrups [3]. moreover, beams with spiral stirrups increased shear resistance and improved ductility and peak deformation compared to beams with commonly used stirrups [4]. meanwhile, it is found that the use of spiral stirrups in place of conventional rectangular stirrups with the same amount in beams improves the beams' torsional ability and performance response [5]. so, to enhance constructability and cost, the structural performance of reinforced concrete columns was developed by using continuous hoops subjected to repeated loads [6]. joshy and faisal [7] have improved the shear capacity and ductility of 12 self-compacting concrete beams, and corte and boel [8] stated that the use of spiral stirrups instead of conventionally stirrups under the bending test. also, shataratet et al. recommended using spiral shear stirrups with an angle of about 80° to http://qu.edu.iq/ mailto:inm.khld@atu.edu.iq https://doi.org/10.30772/qjes.v15i1.808 http://creativecommons.org/licenses/by/4.0/ thaer j. mohammed and khalid m. breesem /al-qadisiyah journal for engineering sciences 15 (2022) 018–022 19 improve the ductility and shear behavior of the beams and reduce labor costs [9]. in addition, continuous spiral stirrups are recommended in the scc beam at an angle of 85° regardless of the spacing between them. it enhances the shear capacity and reduces the construction cost [10]. thus, it is found that few researchers use spiral stirrups rather than traditional vertical stirrups [11]. since the shear failure mechanism is complex, the experimental test of beams underestimated the contribution of the stirrups but increased the contribution of the concrete component. in contrast to analytical methods, stirrups do not reach yield upon failure [12]. in general, structural analysis is very complex. therefore, finite element analysis (fe) is used to simulate realistic problems of structures and obtain approximate solutions. finite element analysis has been used widely by practicing engineers [13-16]. the finite element method can analyze the non-linearity of the behavior of the rc beams. 2. research significance ansys is commercial software for 1d, 2d, and 3d structure behavior analysis by geometric model properties, meshing the different shapes and post-processing. thus, numerous engineering and scientific research use ansys interactive software to evaluate experimental results. in this paper, ansys software is used to study the performance of beams with different continuous spiral stirrups based on the experimental beam that has been obtained from previous research karayannis et al. [17]. 3. numerical analysis the numerical analysis employed is finite element analysis of various engineering applications of ansys software. 3.1. modeling the modeling was performed by using ansys software for beams with various forms of conventional and continuous stirrups and then analyzing these models. then, it was defined as geometric of concrete with both longitudinal and stirrups reinforcement details for the beam. thus, analyzing results reveals the importance of spiral stirrups and the most effective ones for beams to support the literature survey. 3.2. details of beams a numerical study includes three rc beams with a length of 1.84 m, a width of 200 mm, and a height of 300 mm (rectangular section). according to experimental research, the shear reinforcement of concrete beams has been represented by karayannis et al. [17]. the beam b1 is with traditional closed stirrups (see fig. 1) and beam b2 is reinforced with continuous spiral stirrups. the type of reinforcement of beam b3 is continuous spiral stirrups with inclined legs. the diameter of the stirrups is constant at 5.5 mm for all beams. the distance between the stirrups is 120 mm with a different pattern to obtain almost the same reinforcement ratio of the stirrups, approximately p=0.002. a new study is added to the numerical analysis by reducing distances between the stirrups to increase the percentage of shear stirrups. therefore, the effect of the ratio of stirrups with different patterns has been studied to enhance the shear behavior of the specimens. also, the effect of the grade of concrete strength on the shear strength has been studied. 3.3. material properties the steel reinforcement and concrete material properties by karayannis et al. [17] have been used in ansys software in accordance with the experimental results as listed in table 1. figure 1. traditional closed and spiral stirrups of beam b1 and b2 table 1. material properties of specimens concrete steel tensile strength, (mpa) 02.85 stirrup steel (mpa) 220 compressive strength (mpa) 28.50 longitudinal steel (mpa) 500 young’s modulus (gpa) 25.00 young’s modulus (gpa) 200 poisson’s ratio 00.20 poisson’s ratio 0.3 3.4. meshing and loading the concrete and steel reinforcement were modeled in the ansys program [18]. a quadrilateral mesh of concrete was used to obtain good results, as shown in fig.2. the number of mesh elements and nodes are 9854 and 12728, respectively. the location of two-point loading with pinned supports on both ends of the model is represented. the applied loading was at two points with the distance between it 200 mm in the midspan apart of the beams. meanwhile, the distance between two supports of the beam was 1.64 m apart. 3d spar elements represent the longitudinal and transverse steel reinforcement as link elements (see fig. 3). thus, the compatibility between practical and numerical data is achieved. 20 thaer j. mohammed and khalid m. breesem /al-qadisiyah journal for engineering sciences 15 (2022) 018–022 figure 2. quadrilateral mesh of concrete figure 3. link elements of different steel reinforcement 3.5. linear analysis of specimens this work uses the ansys program to perform a linear analysis of beams. the shear failure occurred after several attempts with maximum and minimum loading steps, leading to convergence failure at small loading increments. 3.6. effect of stirrup ratio on shear behavior in this paper, the numerical results have been verified by comparing them with experimental results in the literature reviews. table 2 presents a numerical and experimental comparison of the shear strength of specimens with different types of spiral and closed stirrups. the numerical data analysis indicated shear failure for all beams consistent with the experimental data analysis. in addition, the results revealed that the shear strength of spiral reinforcement beams is higher than a conventional beam. fig. 4 shows the 4. results and discussions in this section, load-deflection curve of the beam has been obtained by numerical analysis. in started, the high-resolution fe analysis is compared to the experimental beams. then, the load-deflection curves defined from the fe analysis are less inconsistent with experimental curves after the cracks of the beam occurred because the perfect bond between beam components (steel reinforcement and concrete material) led to fe results having more stiffness. in general, the diagonal shear stress appeared in beams. according to the behavior of the curves of specimens, the results reveal that the spiral stirrups have higher shear strength than closed stirrups. this information agrees with karayannis c. g. et al. [17]. in general, the behavior all curves of the beams b2 and b3 with continuous shear reinforcement showed that the shear strength is higher than the specimen b1 with stirrups closed. moreover, the performance of specimen b3 showed more ductility improvement than the other beams on shear failure as compatible with experimental results chalioris ceand karayannis cg. [19]. table 2. comparison between numerical load and experimental load of beams [17] bea m crackin g load (exp) crackin g load (ans) ultima te load (exp) ultima te load (ans) differen ce crackin g load differen ce ultimate load b1 148 135 215 210 1.096 1.024 b2 150 135 247 250 1.111 0.988 b3 150 135 252 260 1.111 0.969 mean 1.106 0.994 standard deviation 0.009 0.028 figure 4. the load-defection of the beam with different pattern stirrups thaer j. mohammed and khalid m. breesem /al-qadisiyah journal for engineering sciences 15 (2022) 018–022 21 4.1. shear patterns the finite element analysis was performed to predict crack development in concrete beams. ansys records a shear stress during the loading phases. the result of all beams appeared failure shear. in the beginning, no cracks of all beams were observed, and the behavior was essentially linear until the first crack was obtained. thus, propagation of diagonal shear stress was observed in these beams. new diagonal cracks appeared with increasing loads, as the number of cracks increased parallel to the primary cracks until the final load. thus, one crack developed significantly from the other cracks resulting in sample failure. for beams with different stirrup patterns, fe showed that the diagonal shear stress appear in concrete under the point loading toward the supports of the beam. so, beams with spiral stirrups have shear failure because enough longitudinal steel in the flexure area led to incline cracks appearing in concrete faster. for example, fig. 5 shows crack patterns deformation in concrete and steel on beam b2 at failure. diagonal shear stress appeared within the shear test. as a result, the beam reinforcement pattern led to the typical shear patterns shatarat et al. [10]. figure 5. shear patterns in concrete and steel of beams b1, b2 and b3 at failure. in this section, some numerical parametric study is included, like compressive strength of concrete and ratio of spiral reinforcement on shear strength. for getting more information, the impact of concrete strength on the shear strength has been studied. therefore, the compressive strength of concrete is increased from f'c to 1.5 f'c and 2f'c mpa for beams b1, b2 and b3, respectively. for beam b3, the numerical result indicates the appreciable increase in shear strength of beams of about 21 % and 39% with an increased grade of concrete from 1.5 f'c and 2 f'c, respectively. also, it is noticing the shear strength response of all beams is better, as indicated in fig. 6. figure 7 presents the shear strength of specimens with spiral stirrups reinforcement distances equal 120, 100, and 80 mm. the effect of the increased ratio of spiral stirrups on the shear capacity of specimens is about 5%, while the change distance between spiral stirrups is from 120 mm to 80 mm. the shear behavior of the rc beams depends on the shape of reinforcement of the stirrups. it also depends on the concrete strength by comparing different shapes of spiral stirrups in rc beams with conventional stirrups. figure 6. effect compressive concrete on different pattern stirrups of beams figure 7. effect ratio of stirrups on different pattern stirrups of beams 5. conclusions in this paper, the shear performance of traditional and continuous spiral reinforced concrete beams is investigated. these beams are analyzed using the ansys program and compared with the practical results from previous research. numerical analysis indicted that the increasing in the grade of concrete to 1.5fc and 2fc led to increase the shear strength of the beam by about 21% and 39% respectively. the effective ratio of spiral stirrups by the less distance between stirrups from 120 to 80 mm is increased the shear strength of the beam by approximately 5%. the spiral stirrups configurations improved failure mechanisms and shear response compering with the same beam with conventional stirrups. the beam with spiral 22 thaer j. mohammed and khalid m. breesem /al-qadisiyah journal for engineering sciences 15 (2022) 018–022 transverse reinforcement is enhanced performance and ductility response. meanwhile, the beam with conventional stirrups showed the failure of the brittle shear. the numerical result is indicated the appreciable increase in shear capacity of all specimens with a high grade of concrete. the effect of the decreased distance between spiral stirrups on the shear capacity of specimens is low. references [1] mas, b., cladera, a., &ribas, c. (2016) “experimental study on concrete beams reinforced with pseudoelastic ni-ti continuous rectangular spiral reinforcement failing in shear”. engineering structures, vol. 127, pp. 759-768. [2] meghana,b. m. andneena,v.( 2018)“shear capacity of rc beams with different patterns of spiral reinforcements”, international journal of engineering research & technology (ijert) etcea, vol. 6. [3] karayannis, c. g. (2015) “mechanics of external rc beam-column joints with rectangular spiral shear reinforcement: experimental verification”. meccanica, vol. 50, issus 2, pp. 311-322. [4] karayannis, c. g., &chalioris, c. e. (2013) “shear tests of reinforced concrete beams with continuous rectangular spiral reinforcement”. construction and building materials, vol. 46, pp. 86-97. [5] chalioris, c. e., &karayannis, c. g. (2013) “experimental investigation of rc beams with rectangular spiral reinforcement in torsion”. engineering structures, vol. 56, pp. 286-297. [6] eom, t. s., kang, s. m., park, h. g., choi, t. w., &jin, j. m. (2014) “cyclic loading test for reinforced concrete columns with continuous rectangular and polygonal hoops”. engineering structures, vol. 67, pp. 39-49. [7] joshy, v., & faisal, k. m. (2017) “experimental study on the behaviour of spirally reinforced scc beams”. int j eng res general sci, vol. 5, issus 3, pp. 96-105. [8] de corte, w., &boel, v. (2013) “effectiveness of spirally shaped stirrups in reinforced concrete beams”. engineering structures, vol. 52, pp. 667-675. [9] shatarat, n., katkhuda, h., &alqam, m. (2016) “experimental investigation of reinforced concrete beams with spiral reinforcement in shear”. construction and building materials, vol. 125, pp. 585-594. [10] shatarat, n., mahmoud, h. m., &katkhuda, h. (2018) “shear capacity investigation of self compacting concrete beams with rectangular spiral reinforcement”. construction and building materials, vol. 189, pp. 640-648. [11] askandar, n. h., & mahmood, a. d. (2020) “torsional strengthening of rc beams with continuous spiral near-surface mounted steel wire rope”. international journal of concrete structures and materials, vol. 14, issus 1, pp. 1-16. [12] zhang, t., visintin, p., &oehlers, d. j. (2016) “shear strength of rc beams with steel stirrups”. journal of structural engineering, vol. 142, issus 2, 04015135. [13] zi-xiao, z. h. a. n. g., lie-ping, y. e., & xin-zheng, l. u. (2005) “finite element analysis of shear behavior of rc beams strengthened with u-shaped frp sheets”. engineering mechanics, vol. 22, issus 4, pp. 155-162. [14] ghahremannejad, m., &abolmaali, a. (2018) “prediction of shear strength of reinforced concrete beams using displacement control finite element analysis”. engineering structures, vol. 169, pp. 226-237. [15] kim, s. h., han, s. j., & kim, k. s. (2019) “nonlinear finite element analysis formulation for shear in reinforced concrete beams”. applied sciences, vol. 9, issus 17, pp. 3503. [16] mansour, w., &tayeh, b. a. (2020) “shear behaviour of rc beams strengthened by various ultrahigh performance fibre-reinforced concrete systems”. advances in civil engineering, 2020. [17] karayannis, c. g., chalioris, c. e., &mavroeidis, p. d. (2005) “shear capacity of rc rectangular beams with continuous spiral transversal reinforcement”. wit transactions on modelling and simulation, pp. 41. [18] ansys workbench 14.5 help, 2012. [19] chalioris ce, karayannis cg. experimental investigation of rc beams with rectangular spiral reinforcement in torsion. engineering structures. 2013 nov 1;56:286-97. article al-qadisiyah journal for engineering sciences 14 (2021) 048–053 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: hussam.khalaf@utq.edu.iq (hussam ali khalaf) https://doi.org/10.30772/qjes.v14i1.743 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. the effect of rotational speed on the performance of the electric submersible pump wisam nathem abd a , hussam ali khalaf a,b,* and f. kh. tazyukov c apetroleum and gas engineering department, college of engineering, university of thi-qar, iraq. bmechanical engineering department, college of engineering, university of thi-qar, iraq. ckazan national research technological university, russia, kazan. a r t i c l e i n f o article history: received 24 april 2021 received in revised form 22 may 2021 accepted 23 may 2021 keywords: rotating speed pump performance electric submersible pump a b s t r a c t electric submersible pump (esp) is a centrifugal pump with several stages. it's a dependable and efficient industrial lifting tool for lifting different amounts of fluids, and it's known for its adaptability and reliability. esps are commonly used in onshore oil wells, as well as underground pumping and other applications. pump's efficiency is evaluated under the control of various rotational speeds. cfd approach has been used in this study to analyze flow behaviors within the esp at various flow speeds. ansys cfx program was approved to conduct and investigate single-stage simulation of the gn7000 pump. also, the sensitivity of the network has been determined. the flow field has been solved by using sst, unsteadyrans model with different rotational velocities (2500-3000-3500 cycle in this case). the test used two types of fluids with varying viscosities. findings revealed that the viscosity has an impact on efficiency as well. there is a high level of compatibility as compared to previous studies. this research presented a set of curves for efficiency and pressure and to know the extent of the effect of rotational speed on performance in general. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction esps are one of the most widely used synthetic lifting technologies in the industry because of its broad applicability in viscous oil flows thomas et al., [1]. fluid receives energy in the form of pressure, which raises to the surface in this method of pumping. esp is divided into stages, each of them consists of a rotor that moves vertically, in additional to diffuser that is fixed (stationary). due to a strong rotation exerted on it, the rotor provides the velocity of the fluid then its guided to the pump's outlet by the diffuser , in other words, to the next stage of the pump. for example, the rotor and the diffuser of reda gn7000 style of centrifugal pump used in the lift oil are shown in fig. 1. in recent years, a huge number of studies have been conducted aimed at a better understanding of esp such as, estevam, [2] and amaral, [3]. discovery of oil, make companies to increase their use of this tool along the world. also, the electrostatic precipitator itself is more effective in marine applications than other synthetic lift systems http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ hussam ali khalaf, wisam nathem abd, f. kh. tazyukov /al-qadisiyah journal for engineering sciences 14 (2021) 048–053 49 it is necessary to know that pressure losses present in both rotor and diffuser at each point in order to test the esp system's efficiency. the efficiency of the pump is determined by the output of each point. pump output curves are crucial since they describe the pump's efficiency. the impact of various spin speeds on pressure differences, as well as the impact on the efficiency of the esp and other factors that cause failure, will be discussed. it is critical to understand each category of failure in order to assess results. the hydraulic institute's pump curves are commonly used in the industry and are a valuable guide for the use of centrifugal pumps. however, since these curves are built with water as the test fluid, they are inadequate as a benchmark for esp results. in oil industry, oil from different regions have different properties, viscosity has a direct impact on the velocity and the pressure losses in the esp level, and thus on their efficiency. several previous experiments on the effects of rotational velocity and viscosity have been conducted, and the findings of these studies have been published. researchers have studied the effect of speed on performance for example, yang y. et al. [4], zhou l. et al. [5], and others who studied the effect of viscosity on esp performance like amaral et al. [6], gulich j.f [7], barrios l.j. et al. [8], paternost g.m. et al. [9], zhu j. et al. [10], ofuchi e.m. et al. [11], patil a. and morrison g. [12]. figure 1vane diffuser and impeller blade, one stage, [3]. one of the assumptions in this paper is that the temperature is constant and fluid is in one phase, and the test was done by both water and oil fluids. noting that the viscosity of water is 1cp, and thi qar oil for one of its wells has a viscosity of 24.98cp at a temperature of 21◦c. when comparing this research with stel’s research, in the current research it has been found a good match through the values has obtained for the pressure difference of water at the available rotational speed (3500 rpm) and at q/qdes =1.5. the value of the pressure difference was (41,000pa) for stel et al. [13] and it was (-42,168pa) for the current research) with an error of 2.81% it is a good number for the purpose of investigation. in the current study, an attempt has been performed to find the best performance of esp in terms of (rotational speed, the losses that occur within a single stage, network sensitivity test and validation of the designed model with previous researchers). 2. numerical methods 2.1. geometry model and mesh generation. model has been designed by using autocad software for the gn7000 pump and it has been simulated by ansys20 to generate a grid mesh for it. the mesh used in this study and shown in fig. 2. the whole field group is about 3,010,000 elements. the network is mainly composed of tetrahedral elements and is at the edges of the blades and the subfield interfaces. as well as the hexahedral elements used in the internal field. the sensitivity of the network was tested taking into account the following parameter (control body scaling adjust amplification face tangle control). figure 2control processes for mesh generation. nomenclature 𝑔 gravity acceleration (m 𝑠 −2) greek symbols h head (m) μ dynamic fluid viscosity kgm -1s-1 qdes,w the volumetric flow rate (𝑚 3/s) ρ density kg m-3 scor scfg the coriolis and centrifugal effects η pump efficiency % p pressure (pa) ɸ specific capacity 𝑅𝑒𝑤 rotating reynolds number γ generic diffusion coefficient of the general transportation 𝐷ℎ hydraulic diameter (m) 𝐷𝑠 length scale of the pump geometries subscripts u average peripheral or tangential flow velocity (m s -1) i inlet δp pressure difference o outlet t time z blade number d diameter symbols b blade height ∂ derivative e blade thickness ∇ gradient β blade angle 50 hussam ali khalaf, wisam nathem abd, f. kh. tazyukov /al-qadisiyah journal for engineering sciences 14 (2021) 048–053 fig.3 illustrates the control process in grid generation where the operating load is set to flow rate q/qdes=1and rotation speed of 3500 rpm to calculate the pressure difference values across the field. in fig.3 it has been noticed that the greater the number of elements of the grid by making improvements, the less the deviation in the pressure difference. therefore, the closest value was obtained through the grid used in this research in comparison with the research of stel et al. [13] and was adopted in this study. figure 3mesh sensitivity test results; comparison between numerical results and experimental value [3]. 2.2. boundary conditions and main specifications fluids have been modelled by using ansys cfx software in a variety of ways, including geometry and grid forming. fluid analysis problem has been solved by using pre-treatment based on navier-stokes's equations. the cfx program can solve unstable governing equations. the mass and momentum equations known as the reynolds averaged navier stokes's equations (u-rans) can be expressed in the following general form: 𝜌 (𝜕∅ 𝜕𝑡⁄ + 𝛻. (�⃗� ∅)) = 𝛻. (𝛤𝛻∅) + 𝑆 (1) the pump has designed to spin at 3500 rpm (58.33 rev/sec) with ndes=3500 rpm. the producer's productivity is at its peak when working with water. it has a volumetric flow rate of 1.360x10-2, a mass flow rate of 13.6 kg/s, and a head of 9.6 m. that the designing volumetric flow rate will change if the impeller's spinning speed changes.; q des,w = (n 3500⁄ )×1.36×10-2 (2) there are four subdomains in the dominant domain. the in-port domain (the intake), rotor domain (the impeller), the stator domain (the diffuser), and the out-port domain (the discharge port) are the four domains, respectively. the inlet face has a continuous reference pressure, pref = 0 (pa), with a turbulence slope and flow direction of zero. facade surfaces are used to link sub-domains together (connecting fixed and rotating areas). non-slip surfaces are required on all surfaces. a boundary state interface with a given discharge fluid flow rate value is known as the outlet surface. 3. results and discussion 3.1. pressure difference all simulation conditions have been summarized in table 1; and all of these cases simulated for 2500, 3000 and 3500 rpm. by using mpi parallel calculation with 6 cpu processors with a pc of specifications (intel coretm i9 cpu 3.5 ghz 32 gb ram). the simulations need 33 runs where each run demands approximately 36 hrs. table.1 summary of simulation conditions however, the fig. 4 shows the pressure difference with respect to flow rate values for water as a working fluid at three different impeller speeds. it has shown that as the angular velocity of impeller increases, the pressure difference also increases. this is because as impeller rotating became faster, the flow behaves as a blockage at the rotor zone. thus, more flow force needs to penetrate this block of fluid, which lead to increase pressure difference across the pump stage. in addition, in the high flow rate cases, the effect of rotational speed degrades on pressure difference. it was found that the pressure changes for volumetric flow rate of q/qdes = 1.5 is 44.8141% and 32.0046% for 2500 rpm and 3000 rpm respectively lower than n=3500 rpm case. and in the case of q/qdes = 0.5, the pressure difference is 71.9994% and 37.298% for 2500 rpm and 3000 rpm respectively lower than n=3500 rpm case. figure 4-comparison of pressure difference for water 1cp, at several rotor speeds. c a se w o rk in g f lu id v is c o si ty ( c p ) d e n si ty (k g /m 3 ) f lo w r a te (k g /s ) r e y n o ld s n u m b e r 1 pure water 1 998.2 3.4 47,674 2 pure water 1 998.2 6.8 95,348 3 pure water 1 998.2 10.2 143,022 4 pure water 1 998.2 13.6 190,696 5 pure water 1 998.2 17 238,370 6 pure water 1 998.2 20.4 286,044 7 oil 24.98 889 3.022 1,699.705 8 oil 24.98 889 6.045 3,399.410 9 oil 24.98 889 9.0678 5,099.116 10 oil 24.98 889 12.0904 6,798.82 11 oil 24.98 889 15.113 8,498.52 hussam ali khalaf, wisam nathem abd, f. kh. tazyukov /al-qadisiyah journal for engineering sciences 14 (2021) 048–053 51 the fig. 5 shows similar comparison for the 24.98 cp fluid. the same observations verified by look to these curves. the pressure difference proportion directly to the angular velocity of impeller. it's evident from the previous estimates that as the flow rate increases, the velocity of the inlet flow rises with it. this rise in inlet velocity induces more shearing of the fluids and more energy loss. as a result, the pressure differential decreased in situations where the flow rate was higher. also, in the following figure, it’s obvious that for higher fluid viscosity, the pressure rise is lower. it is the same influence of flow rate increasing. figure 5comparison of pressure difference for oil 24.98 cp, at several rotor speeds. also, from the above comparison, it can be observed that the pressure rise is highest in the lowest flow rate condition for each fluid. as the flow rate become higher, the pressure difference decreased for fluid with operating condition or high-capacity condition. for the case of q/ qdes,w = 1.5 at 3500 rpm, the pressure contour is shown in the fig.6. the higher-pressure difference appears in the impeller region due to rotational motion. the secondary flow generated lead to high pressure difference around the blades. therefore, the pressure difference in the impeller is approximately like the pressure change of the whole stage. figure 6the pressure contour for the case of q/ qdes, w = 1.5 at 3500 rpm. 3.2. analyze the results in order to approximate the pump efficiency, the following equation was used: 𝜂 = (𝜌 𝑔 𝑄 𝐻)/𝑇𝜔 = (𝑄 ∆𝑝)/𝑇𝜔 (3) q represents the flow rate (m3/s), h represents the head (m), represents the angular speed (rad/s), and t represents the torque (n.m). torque that can be measured directly from the cfd-post function calculator in the ancyc cfx program. the xy diagrams for the pump's performance in clear water and another fluid with a viscosity of 24.98 cp for various impeller speeds are published in the following figures. a comparison of two fluids (water and oil) at two different rotational speeds is seen in the diagram below (3000 and 3500 rpm). at the same rotational speed, the highest output point for various viscosity fluids is (3500 rpm). when working with water, q / qdes = 1 is the flow rate at the best performance stage. when treating a fluid with a viscosity of 24.98cp, the flow rate drops to q / qdes = 0.8 at the best efficiency stage. when it is interacting with a lower rotational speed, the same explanation can be seen (3000 rpm). the best performance point has declined, as we can see. it might assumed that the rotational speed has a significant impact on efficiency and that the viscosity of the esp is affected. figure 7best efficiency points are different for various rotational speed and viscosity fluids. the best performance point shifts from q/qdes =0.8 at 3500 rpm to roughly q/qdes =0.68 at 2500 rpm, as seen in the graph above. this is because as the rotational speed reduces, so does the angular flow speed. for a constant volumetric flow rate, this resulted in the velocity vector in diffuser flow not being in the same direction. to achieve the same combination of axial and angular velocity in the diffuser component, the flow rate should be reduced as well. in the diffuser and out-port areas, this mixture resulted in blade-oriented flow. however, in the considered esp model, the best performance point shift for both water and oil flow. figure 8efficiencies for three rotational speeds is explained in xy plot for oil flow. 52 hussam ali khalaf, wisam nathem abd, f. kh. tazyukov /al-qadisiyah journal for engineering sciences 14 (2021) 048–053 3.3. dimensionless analyses it was determined to do a dimensionless analysis. the dimensionless numbers were used in this analysis to investigate the effect of viscosity on esp performance. the equations below have been used to calculate the dimensionless numbers. the precise capability; 𝛷 = 𝑄 𝜔𝐷𝑠 3 (4) using q is the stage's flow rate (m3/s), 𝜔is the impeller's angular speed (rad/s), and ds is the impeller outlet mean diameter, which is the average of the inner and outer diameters. the value of ds in this model is 0.0884 m. there's also the spinning reynolds number to consider. rew= 𝜌𝜔𝐷𝑠 2 𝜇 (5) where 𝜌 is the operating fluid's density (kg/m3) and 𝜇 is the fluid's mechanics viscosity (kg/m.s). the rotating reynolds numbers for all simulation cases are described in the table 2. the rotational reynolds number gives the same impression as the traditional reynolds number. table.2. rotating reynolds numbers for all simulated cases. water oil n=2500 n=3000 n=3500 n=2500 n=3000 n=3500 2042161.4 7 2450597. 4 2859030. 3 72808.45 9 87370.280 3 101931.99 4 the increasing of velocity (in this case angular velocity) led to increasing rew. the increase of viscosity results to reducing of rew value. however, the fig. 9 shows the efficiency versus specific capacity; it has been shown that increasing the revolving reynolds number increased pump efficiency. points calculated from simulation data. using microsoft excel, the curves were applied using a polynomial of the fourth order trend. these performance curves have a starting point that is roughly at the origin. based on figure, the efficiency of esp is a function of the specific capacity and the rotating reynolds number. figure 9efficiency versus specific capacity. 4. conclusion this research has been presented a numerical study of the gn7000 esp that was designed and tested under different rotational velocities and flow rates to create specific operating conditions. the conclusion includes the following aspects: 1. the arithmetic field was created for one stage with a highquality structural network, and the sensitivity of the network was analyzed to determine the appropriate network and it was good when compared with previous research. 2. the results showed that the pressure difference with respect to the values of the fluid flow rate working at three different impeller speeds, that with increasing the rotational speed, the pressure difference increases. 3. in high flow rate situations, the effect of rotational velocity on the pressure difference decreases. 4. when comparing the rotational speed (3500-3000-2500 rpm), it was found that the best performance point for different viscous fluids with the same rotation speed is 3500rpm. references [1] j. e. thomas, a. triggia, c.a. correia, c.v. filho, j.a.d. xavier, j.c.v . machado, j.e. filho, j.l. paula, n.c.m. rossi, n.e.s. pitombo, p.c.v. gouveia, r. carvalho, r.v. baragan, fundamentals of petroleum engineering. second edition. rio de janeiro: editora interciência, 2001. [2] v. estevam, a phenomenological analysis of the centrifugal pump operation with two-phase flow, phd thesis, faculty of mechanical engineering, state university of campinas, campinas, 2002. [3] g.d.l.do amaral, modeling of single-phase flow in submerged centrifugal pump operating with viscous fluids, msc thesis, faculty of mechanical engineering, state university of campinas, campinas, 2007. [4] yang yang, ling zhou, weidong shi, chuan wang, wei li, ramesh agarwal, effect of rotating speed on performance of electrical submersible pump, asme-jsme-ksme 2019 8th joint fluids engineering conference isbn: 978-0-7918-5905-6, 2019. [5] ling zhou, wanhong wang, jianwei hang, weidong shi, hao yan, yong zhu, numerical investigation of a high-speed electrical submersible pump with different end clearances, water 2020, 12(4) (2020) 1116; https://doi.org/10.3390/w12041116 [6] g. amaral, v. estevam, f.a. franca, on the influence of viscosity on esp performance. spe production and operations, 24(02) (2009) 303-311. [7] j.f. gülich, pumping highly viscous fluids with centrifugal pumps part 2. world pumps, 396 (1999) 39-42. [8] l.j. barrios, s.l. scott, r. rivera, k.k. sheth, esp technology maturation: subsea boosting system with high gor and viscous fluid. in spe annual technical conference and exhibition. society of petroleum engineers. spe-159186-ms, 2012. [9] g.m. paternost, a.c. bannwart, v. estevam, experimental study of a centrifugal pump handling viscous fluid and two-phase flow, spe production and operations, 30 (02) (2015) 146–155. [10] j. zhu, h. banjar, z. xia, h. zhang, h-q. zhang, cfd simulation and experimental study of oil viscosity effect on multi-stage electrical submersible pump (esp) performance. journal of petroleum science and engineering, 146 (2016) 735-745. [11] e.m. ofuchi, h. stel, t.s. vieira, f.j. ponce, s. chiva, r.e.m. morales, study of the effect of viscosity on the head and flow rate degradation in different multistage electric submersible pumps using dimensional hussam ali khalaf, wisam nathem abd, f. kh. tazyukov /al-qadisiyah journal for engineering sciences 14 (2021) 048–053 53 analysis, journal of petroleum science and engineering, 156 (2017) 442– 450. [12] a. patil, g. morrison, affinity law modified to predict the pump head performance for different viscosities using the morrison number. asme journal of fluids engineering, 141 (2) (2019) 021203. [13] h. stel, t sirino, f.j. ponce, s. chiva, r.e.m. morales, numerical investigation of the flow in a multi stage electric submersible pump. journal of petroleum science and engineering, 136 (2015) 41-54. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 16 shear transfer strength of steel fiber reinforced concrete dr. muhaned a. shallal lect. sallal r. alowaisy qadissiya university / college of engineering civil eng. dept., college of engineering al-qadisiya university, al-diwania, iraq wasit university, kut, iraq abstract push-off tests were performed and a finite element model was adopted to study the influence of steel fibers on shear transfer strength of concrete. nine push-off specimens were used. the specimens were divided into three groups each of a definable amount of steel fibers. also, the amount of steel stirrups crossing the shear plan was variable. the results show that the use of steel fibers in combination with steel stirrups can minimize the required amount of stirrups and improve strength and ductility. comparing test and theoretical results with the provisions of aci-05 code, it is concluded the aci-05 shear-friction method gives a very conservative estimate of shear transfer strength of concrete. للخرسانة المسلحــة باألليافالقصمقاومة انتقال صالل راشد عبد العويسي اللــهند عالوي شــم. د آلية الهندسة /سط جامعة وا آلية الهندسة/ جامعة القادسية قسم الهندسة المدنية قسم الهندسة المدنية :الخالصة وتبني موديل للعناصر المحددة لدراسة تأثير أأللياف الحديدية على ) push-off(نماذج خاصة دراسة في هذا البحث تم القيام ب آذلك . ثالثة مجاميع حسب نسبة ألياف الحديد المستخدمةإلىالنماذج مت قس فحص تسعة نماذج و تم. خرسانةمقاومة انتقال القص لل أظهرت النتائج أن استخدام ألياف الحديد باالشتراك مع حديد . التي تقطع مستوى القص متغيرة) األترية(آانت آمية حديد القص النظرية العملية وآما تبين المقارنة بين النتائج. المطيلية ع تحسين في المقاومة و أن يقلل آمية حديد القص الالزمة مبإمكانهالقص في المدونة األمريكية أن طريقة المدونة األمريكية في حساب ) shear-friction(االحتكاك -لهذا البحث مع الفقرات الخاصة بقص .متحفظة جدًا مقاومة انتقال القص تعتبر dr. muhaned a. shallal qadissiyah university / college of engineering civil engineering department sallal r. alowaisy wasit university / college of engineering civil engineering department al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 17 introduction portland cement concrete can be considered as a brittle non-ductile material when subjected to tensile stresses. this has been solved since the nineteenth century by using steel reinforcing bars within the concrete to carry tensile loads. since the early 1960s, extensive research on steel fiber reinforced concrete (sfrc) showed that the addition of steel fibers can increase the tensile load capacity of concrete mix and keeps the crack width as small as possible. the problem of shear behavior and ultimate shear strength of concrete members was examined many years ago. many researches on fiber reinforced concrete beams indicate that fibers substantially improve the shear (diagonal tension) capacity of concrete beams. in some practical structures such as corbels, pre-cast concrete connections and interface between different concretes, shear stresses transfer at a definable plan. the push-off specimens are more suitable for studying shear transfer in such structures than conventional beams. in this work, push-off specimens were used to investigate the influence of the addition of steel fibers on shear transfer strength and to study the possible amount of contribution of commercial percentages of steel fibers in carrying shear loads in contribution with reinforcing steel stirrups. failure envelope of concrete for this study the formulation of the failure envelope proposed by william and warnke (6) was adopted with the parameters; ft and fc. the failure criteria of concrete due to a multi-axial stress state can be expressed in the form 0s fc f ≥− (1) where f: a function of principal stress state; s: failure surface expressed in terms of principal stresses and some parameters, which are depending on fc, ft; fc: uniaxial compressive (crushing) strength; ft: uniaxial tensile strength. concrete uniaxial stress-strain relationships in compression for the nonlinear shear analysis of the test model, it is essential to understand the stressstrain behavior of frc (fiber reinforced concrete) in compression. in this paper, the stress-strain al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 18 relationship proposed by khuntia et. al, 1999 is used, which can be applied to both normal and high-strength concrete with or without steel fibers, and is given as ⎪ ⎪ ⎪ ⎭ ⎪ ⎪ ⎪ ⎬ ⎫ ⎪ ⎪ ⎪ ⎩ ⎪ ⎪ ⎪ ⎨ ⎧ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ′ + − += nn cc cc cfk e q qefc 1 1 1 ε ε (2) where: cf ′ = compressive stress of frc at a strain of cε . k, q, and n are the nondimensional factors defined as follows: k=0.6+1.08/f0.16 (k = 2.85 for f = 0, i.e., for concrete without fibers) q=(0.26-0.40/f0.28)z1.4 (q =-0.9z2.1 for f = 0) n =1.5z0.58 (n =1.5+(z-1)0.8 for f = 0). z = 28/cf ′ ( cf ′ in mpa). fiber reinforcing index f = (vf lf /df), where vf, lf, and df are volume fraction, length, and diameter of the fiber, respectively. cf ′ = compressive strength of frc. ec = elastic modulus of frc, given by ec 2/ec2/ec// ⊥+= (5); where //ec is the elastic modulus of frc in aligned condition (upper bound) equal to efvf+ em(1-vf ) and ⊥ec is that in perpendicular fiber condition (lower bound) equal to ef em/[ef (1-vf )+emvf ]. ef and em are the elastic modulus of fiber and matrix, respectively. for simplicity, the elastic modulus of frc (ec) can be taken equal to that of the matrix (em). a comparison of the behavior of frc in compression with that of normal concrete is shown in figure (1-a). as shown in the figure, frc possesses a partial confinement effect. the strain corresponding to peak stress of frc, ofε , can be expressed as 1999 cf f oof ′ += 65.0 00683.0εε (3) al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 19 where oε is the compressive strain of normal concrete at peak stress which equals 0.002 for normal-strength concrete, and can be taken as 0.002+( cf ′ -28) * 0.72 * 10-5 for strengths greater than 28 mpa. the value of ultimate compressive strain can be conservatively taken as twice that of strain at peak stress for all frc strengths 1999. concrete uniaxial stress-strain rrelationships in tension the stress-strain response of a concrete member in uniaxial tension is initially almost linear elastic. near the peak load, the response becomes softer due to micro cracking. for simplicity, the distribution of post-cracking tensile stress of frc is assumed to be triangular (khuntia, 1999). figure (1-b) shows the typical stress-strain curve for concrete in tension with and without steel fibers. steel stress-strain relationships in tension and compression the stress-strain curve of reinforcing steel was modeled by an idealized bilinear curve identical in tension and compression as shown in figure (2). experimental program push-off specimens were used in this work to study the enhancement on shear transfer strength due to the presence of steel fibers. the push-off specimens were 440mm in length, 200mm in width and were 100mm in thickness with 200mm shear plan length as shown in figure (3-a). two variables were investigated; the first was the fiber content. three steel fiber contents (vf %) of (0.0, 0.5 and 1.0 %) by volume were used. while the second variable was the amount of shear reinforcement crossing the shear plans. one specimen from each group was designed without shear reinforcement crossing the shear plan. while the second specimen was designed with one 10mm diameter closed stirrup (2 legs) and the third specimen was reinforced with two 10mm diameter closed stirrup (4 legs), table (1) summarizes the specimen's properties. additional reinforcement was provided away from the shear plan to prevent failure other than the shear plan ,1972. the used materials were as follows: ordinary portland cement from kubaisa factory; washed graded local natural sand from al-ukhaider; and crushed graded local gravel with maximum size of 19mm from al-nebaey region. the steel fibers were (duramix type) with 0.5mm diameter and 30mm length (aspect ratio l/d= 60) and ultimate strength of 1177 mpa. a single concrete mix was used in this study with mix proportion by weight of (1: 1.5: 3) (cement: sand: gravel) and with al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 20 water cement ratio of 0.5. the concrete was mixed according to the fifth mixing procedure recommended by aci 544.1r-82 ,1982. the concrete was placed in the moulds in two layers and was externally vibrated using a table vibrator as recommended by aci 544.2r-89 ,1989. all specimens including control specimens were prepared, cast and vibrated as recommended by aci 544.2r-89 ,1989, and were tested at age of 28 days. the push-off specimens were loaded concentrically using a hydraulic testing machine as shown in figure (3-b).with each concrete mix, three 150mm cubes were prepared to test the compressive strength of concrete. also, six (150×300 mm) and three (100×200 mm) cylinders were prepared to find the cylinder compressive strength, static modulus of elasticity and splitting tensile strength respectively. ansys computer program a finite element model was proposed to represent the push-off specimens using the (ansys 5.4) finite element computer program. the out-put of this computer program was used to study the concrete shear transfer behavior and to compare with the experimental results. the three-dimensional finite element representation mesh for the specimen using (ansys 5.4) software is shown in figure (4). the concrete is idealized by using (608) eight-noded brick elements (solid 65-reinforced element), steel reinforcement is idealized by using (184, 200, 216) two-noded bar elements (link 8bar element). the total number of nodes is 945. ultimate strength the ultimate shear transfer strength is defined as the maximum shear that the test specimens can carry during the test. the shear transfer through the shear plane can be expressed as the ultimate force carried by the specimens divided by the area of the shear plane 1969, 1976. vu= ultimate shear stress (ultimate shear force/ area of shear plane) in this research, the shear force equals the applied load and the shear plane area equals (200 x 100 mm). table (2) shows the values of ultimate shear transfer strength of all specimens with other test data. results of finite element model (ansys results): by the comparison of experimental results with those of finite element model obtained by ansys, it is observed that the percentage error does not exceed 10.62% in the worst case. this percentage of error can be considered as an accepted percentage in the civil engineering field. also, it is noticed that the percentage error increases as the shear steel quantity increase. this result can al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 21 be attributed to the decreasing degree of representation of the steel stress-strain model to the actual behavior as steel stress increase. the deformed shape of specimen number a0 at stress level of 2 mpa is shown in figure (5). the vertical stress in y-direction at load equals 4.8 mpa is shown in figure (6). from this figure it can be seen that the maximum vertical stresses occur near the opening of specimen. effect of investigated parameters based on the investigated parameters and the obtained results in this study, the effect of steel reinforcing stirrups and steel fibers on the shear transfer strength of push-off specimens both individually and in combination are discussed here. effect of shear reinforcement figure (7) shows the shear transfer strength values for the three groups of specimens which have different fiber contents. it is shown that for each group, the shear transfer strength increases as the number of stirrup legs increase. the shear transfer strength for group a specimens (without steel fibers), increases from 5.9 mpa for specimens without shear reinforcement to 9.5 mpa for specimens reinforced with 2 legs of 10mm diameter stirrups. while when 4 legs are used instead, the shear transfer strength increases to 11.65 mpa. similar sequences of increase are recorded for group b and group c specimens as shown in figure (7) and recorded in table (2). this means that for group a specimens, a shear strength increase of 61% and 97.5% occurs when the push-off specimens are reinforced with 2 and 4 stirrup legs respectively. figure (8) shows that the percentage increase in shear transfer strength ranges between 61% and 78.4% for push-off specimens with two legs of 10mm diameter closed stirrups and ranges between 97.5% and 116.2 for 4 legs of stirrups. effect of steel fibers as mentioned previously, two fiber contents of 0.5 % and 1.0 % are adopted in this study in addition to the reference specimens. the effect of the addition of fibers on shear transfer strength of push-off specimens is shown in figures (9) and (10). figure (9) shows that the shear transfer strength increases as the fiber content increases. the shear strength of push-off specimens without shear reinforcement (group a) increases from 5.9 mpa for specimens without fibers to 6.57 mpa and 7.4 mpa for specimens with 0.5 % and 1.0 % fiber content. for group b specimens the sequence is (9.5, 11.1 and 13.2 mpa) for fiber contents of (0.0, 0.5 and 1.0 %) respectively. similar sequence is noticed for group c specimens. the percentage increase in shear transfer strength due to al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 22 the addition of steel fibers of (0.5 % and 1.0 %) is in the range of (11.3 % to 16.8 %) and (25.4 % to 38.9 %) respectively. this increase in shear transfer strength is an expected result since shear failure occurs mostly as direct shear cracks propagated and increased in width, and because the steel fibers show several potential advantages such as; (1) the fibers are randomly distributed through the volume of concrete at much closer spacing than can obtained with reinforcing bars; (2) the first crack tensile strength and the ultimate tensile strength are increased by the presence of fibers; and (3) the shear friction is increased,1988. by the comparison of ansys results with the experimental results, it is shown that ansys results are generally higher than those obtained experimentally. also, it is noticed that the percentage difference increases as the fiber content increases. combined effect of reinforcing stirrups and steel fibers it is reported previously in this paper that the percentage increase in shear transfer strength gained by using 1.0 % of steel fiber does not exceed 26 % compared to plain concrete specimens. while the use of two legs of 10 mm diameter closed stirrups ( yfρ = 3.66 mpa), results in an increase in shear transfer strength exceeding 60 % compared to plain concrete specimens. and when four legs 10 mm diameter closed stirrups ( yfρ = 7.32 mpa) are used, shear transfer strength increases by about 100 %. this may confirms that fibers can not be used individually to resist applied loads without using conventional steel reinforcing bars. on the other hand, it is noticed that using steel fibers in combination with reinforcing steel bars can results in further improvement in shear strength of push-off specimens. where, shear strength increases by about 124% when two legs of 10 mm diameter stirrups are used in combination with 1.0 % of fibers, and increases by about 172 % when four legs of 10 mm stirrups are used in combination with 1.0 % of fibers as compared to plain un-reinforced specimens. another noticeable result is that the use of two legs of 10 mm stirrups in combination with 1.0 % of steel fibers results in higher shear stresses at failure than using four legs of stirrups without fibers. the shear strength of push-off specimens which reinforced with four legs of stirrups without fibers is 11.65 mpa, while for specimens reinforced with two legs with 1.0 % of steel fibers, shear strength is 13.2 mpa. test results of this study confirm that steel fibers significantly increase shear capacity of concrete especially when work in combination with conventional stirrups. also, it confirm that 1.0 percent of steel fibers can replace a part of steel stirrups reaching moderately higher shear stresses al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 23 at failure and improving crack propagation resistance showing higher ductility at failure. however, the steel reinforcement can be placed and distributed in the required orientations and spaced in the required distances to withstand the design loads, while this can not be ensured when steel fibers is used instead, since steel fibers are randomly distributed in the concrete matrix and spread in different positions and orientations, which lead to the conclusion that steel fibers can not be used simply in place of conventional steel bars, it can be used in combination with steel bars to increase concrete ductility, help keeping the crack as small as possible and improve the shear capacity of concrete members. comparison of the study results with the aci-05 code shear-friction provisions. depending on the finite element model obtained by the ansys computer program , many shear transfer strength results were obtained using two different bar diameters, three different steel yield stresses and three fiber contents as shown in table (3). figure (11) shows a comparison between the experimental and the finite element results of this study with the aci-318m-05 code (1) shear-friction design method. it is noticed that the lowest shear transfer strength in this study (specimen a0: no stirrups and no fibers) is higher than the maximum shear transfer strength limited by aci-318m-05 code. section 11.7.5 of aci-318m-05 code limits the maximum shear transfer strength nv by cf ′2.0 or 5.5 mpa times the area of concrete section resisting shear transfer. while in this study, it is found that the shear transfer strength for specimen without reinforcement and fibers is about 6.0 mpa which exceeds the maximum shear transfer strength limited by aci-318m05 code. the shear transfer strength for reinforced specimens without fibers ranges from 8.6 mpa for yfρ of 1.61 mpa to 12.9 mpa for yfρ of 7.58 mpa which confirms that the aci-318m-05 code shear-friction design method is too conservative. when the aci-318m-05 code shear-friction design method is compared with the results of fiber reinforced specimen results, the gap becomes wider. the shear transfer strength for 1% fiber reinforced concrete ranges between (11.7 and 18 mpa) for yfρ of (1.61 and 7.58 mpa) respectively. the aim of the limitation of the maximum shear transfer strength of the aci-318m-05 code to 5.5 mpa is to limit the amount of steel required to resist the shear transfer stresses. depending on the results of this study, it can be concluded that the aci-318m-05 code shear friction design method is too conservative. modifications can be made to this method by taking into account the shear friction resistance of concrete (initial point of the design lines) and raising the upper limit of shear transfer strength to about 8 mpa, which results in conservative design lines with which lower quantities of steel reinforcement can be used to carry higher shear transfer stresses. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 24 conclusions: 1shear transfer strength of concrete enhances noticeably when steel fibers are used. the percentage increase in shear transfer strength was in the range of 25.4% to 38.9% when 1% of duramix type steel fibers are added. 2the use of 1% of steel fibers can replace a part of steel stirrups reaching moderately higher shear strength and showing higher ductility by improving the crack propagation resistance. the use of two legs of 10mm diameter stirrups in combination with 1% of steel fibers results in a higher shear stresses at failure than using four legs without fibers. the shear transfer strength of specimens reinforced with four stirrups legs was 11.65 mpa, while it was 13.2 mpa for specimens with two legs of stirrups and 1% of steel fibers. 3comparing the experimental and the finite element model results of this study with the aci318m-05 code shear-friction provisions, it can be concluded that the aci-318m-05 code shearfriction design method gives a conservative estimate of shear transfer strength of concrete. references: 1. aci committee 318, 2005," building code requirements for structural concrete and commentary," (aci 318m-05), american concrete institute, farmington hills, michigan.. 2. aci committee 544, 1988 "design considerations for steel fiber reinforced concrete," (aci 544-4r-88), aci manual of concrete of practice, part 5, american concrete institute, detroit, 17 pp. 3. aci committee 544, 1988, " measurements of properties of fiber reinforced concrete," (aci 544-2r-89), aci manual of concrete of practice, part 5, american concrete institute, detroit, 11 pp. 4. aci committee 544,1982," state-of-the-art report on fiber reinforced concrete," (aci 544-1r-82), aci manual of concrete of practice, part 5, american concrete institute, detroit, 16 pp. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 25 5. alwan, j.m., and naaman, a. e.,1994, "new formulation for elastic modulus of fiber reinforced concrete, quasi-brittle matrices," journal of engineering mechanics, asce, vol. 120, november , pp. 2443-2460. (cited from ref. 8). 6. ansis help, "ansys theory reference ch. 4-7 concrete," eighth ed., sas ip, pp. 4-48 to 4-56. 7. hofbeck, j. a.; ibrahim, i. o.: and mattock, a. h., 1969, "shear transfer in reinforced concrete," aci journal, proceedings vol.66, no.2, feb. pp. 119-128. 8. khuntia, m., and goel, s.c., 1999, "analytical study of frc-encased steel joint composite beams," journal of structural engineering, asce, vol. 125, no. st5, may pp. 503-509. 9. mattock, a. h.; and hawkins, n. m., 1972, "shear transfer in reinforced concreterecent research," pci journal, vol. 17, no.2, march-april , pp. 55-75. 10. mattock, a. h.; li, w. k.; and wang, t. c.,1976, "shear transfer in light weight concrete," pci journal, v.21, no.1, jan.-feb. pp. 20-39. table (1): push-off specimen properties. specimen no. vf % no. of shear legs shear parameter( yfρ ) (mpa) cuf (mpa) cf ′ (mpa) splitting strength (mpa) ce (gpa) a0 a1 a2 0.0 % 0 2 4 0 3.66 7.32 28.9 23.3 2.85 22.8 b0 b1 b2 0.5 % 0 2 4 0 3.66 7.32 30.6 23.8 3.04 24.1 c0 c1 c2 1.0 % 0 2 4 0 3.66 7.32 29.7 23.9 3.22 28.5 table (2): experimental and ansys shear transfer strength results. specimen no. vf % no. of shear legs shear parameter yfρ (mpa) shear transfer strength (mpa) shear transfer strength by ansys (mpa) error % a0 a1 a2 0.0 % 0 2 4 0 3.66 7.32 5.9 9.5 11.65 6.05 10.0 12.7 2.5 5.27 9.01 b0 0.5 % 0 0 6.57 6.8 3.5 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 26 b1 b2 2 4 3.66 7.32 11.1 13.47 11.8 14.9 6.31 10.62 c0 c1 c2 1.0 % 0 2 4 0 3.66 7.32 7.4 13.2 16.06 7.6 14.0 17.65 2.7 6.06 9.9 table (3): results obtained by the ansys computer program. steel type as (mm 2) as*fy ρfy (mpa) vf % shear transfer strength by ansys (mpa) 0 8.6 0.5 9.8 2lφ8 100.5 280*100.5 1.61 1.0 11.7 0 8.8 0.5 9.6 2lφ8 100.5 350*100.5 2.01 1.0 11.7 0 8.9 0.5 10 2lφ8 100.5 420*100.5 2.412 1.0 12.1 0 10.3 0.5 12.0 4lφ8 201 280*201 3.216 1.0 14.0 0 10.9 0.5 12.5 4lφ8 201 350*201 4.02 1.0 14.9 0 10.8 0.5 12.9 4lφ8 201 420*201 4.824 1.0 15.65 0 9.8 0.5 11.0 2lφ10 158 280*158 2.528 1.0 13.0 0 9.6 0.5 11.4 2lφ10 158 350*158 3.16 1.0 13.7 0 10.1 0.5 11.95 2lφ10 158 420*158 3.793 1.0 14.1 0 11.55 0.5 13.65 4lφ10 316 280*316 5.056 1.0 16.25 0 12.3 4lφ10 316 350*316 6.32 0.5 14.35 al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 27 1.0 17.35 0 12.9 0.5 15.05 4lφ10 316 420*316 7.584 1.0 18.0 crε ft 6.0 ft cr6ε0 1 2 3 4 5 6 7 8 9 compressive strain *10 0 10 20 30 40 50 c om pr es si ve s tr es s (m pa ) vf=0.0 % vf=0.5 % vf=1.0 % vf=2.0 % -3 cr3ε without steel fiber t en si le s tr es s (m pa ) figure (1): uniaxial stress-strain of concrete: (a) compression; (b) tension. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 28 suf syf syε suε s ε sf figure (2): idealized stress-strain for steel bars. 164φ 10φ 102,1,0 φ figure (3) (a) dimensions and reinforcement details of push-off specimen. (b) loading arrangement of push-off specimens. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 29 figure (4) finite element mesh of test specimen figure (5) deformed shape of specimen number a0 at a stress level of 2 mpa. al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 30 figure (6) stresses in y direction of specimen number a0 at a stress level of 4.8 mpa. 0.0 0.5 1.0 fiber content (vf %) 4 6 8 10 12 14 16 18 sh ea r t ra ns fe r st re nt h (m pa ) results experimental ansys shear rein. 0 legs 2 legs 4 legs figure (7) shear transfer strength-fiber content curves for different shear reinforcements. 0.5 1.0 fiber content (v %) 0 10 20 30 40 pe rc en ta ge i nc re as e in s he ar t ra ns fe r st re ng th (% ) f shear rein. 0 legs 2 legs 4 legs figure (8) percentage increase in shear transfer strength-fiber content relationship for different shear reinforcements al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 31 0.0 2.0 4.0 no. of shear legs 4 6 8 10 12 14 16 18 sh ea r t ra ns fe r st re nt h (m pa ) results experimental ansys fiber content 0.0 % 0.5 % 1.0 % figure (9) shear transfer strength-number of shear stirrup legs curves for different fiber contents. 2 4 no. of shear legs 0 20 40 60 80 100 120 pe rc en ta ge i nc re as e in s he ar t ra ns fe r st re ng th (% ) fiber content 0.0 % 0.5 % 1.0 % figure (10) percentage increase in shear transfer strength-number of shear stirrups legs relationship for different fiber contents al-qadisiya journal for engineering sciences vol. 1 no. 1 year 2008 32 0 1 2 3 4 5 6 7 8 fy (mpa) 0 2 4 6 8 10 12 14 16 18 20 v n/ a c (m pa ) µ = 1.4 µ = 1. 0 µ 0.7 µ = 0.6 (vn/ac) limit = 5.5 mpa mod ified she ar-fr ictio n me thod shear friction design method fiber content 0.0 % 0.5 % 1.0 % ρ figure (11) results of this study versus aci-318m-05 code shear friction design method. article al-qadisiyah journal for engineering sciences 15(2022) 113–121 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ckksekyere@knust.edu.gh (charles sekyere) https://doi.org/10.30772/qjes.v15i2.821 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. performance assessment of a solar powered egg incubator with a backup heater p. y. andoha, c. k. k. sekyere*a,b, k. o. amoabenga, and d. e. k. dzebrea a department of mechanical engineering, kwame nkrumah university of science and technology (knust), kumasi, ghana b the brew-hammond energy centre, kwame nkrumah university of science and technology (knust), kumasi, ghana a r t i c l e i n f o article history: received 01 may 2022 received in revised form 03 june 2022 accepted 08 july 2022 keywords: incubator guinea fowl egg temperature range humidity range candling test a b s t r a c t this study presents the performance of a novel solar-powered incubator which uses water as thermal mass. energy absorbed by the water is transferred to the incubator chamber by a fan powered with a 12 v battery. to enable adequate control of chamber temperature and humidity, a pronem mini sensor and controller (esm-3723) were incorporated into the design. the thermal mass was sized adequately to supply energy for night operations as well as periods of inclement weather. the incubator was tested with and without load. field measurements were obtained using ut330a usb datalogger. tests under no load conditions gave an average temperature range of 36 to 42.9°c and relative humidity of 53 % to 70.5 %. incubation tests showed average chamber temperature and relative humidity ranges of 35 ℃ to 41 ℃ and 45 % to 61 %. candling test gave percentage fertility and hatchability of 60% and 56%. a cost -benefit analysis gave a capital cost of 617.32 usd, incubation cost of 69 cents per chick and simple payback period of 15 months. the performance indices obtained make the proposed design a suitable architecture to build upon in order to accelerate the promotion of livelihood empowerment through poultry farming in ghana. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction 1.1. background egg hatcheries are a viable alternative to old-fashioned or traditional backyard chicken production since they come in larger capacities fit for commercial-scale production. it not only improves chicken output greatly, but also provides a consistent source of revenue, making rural poultry farming a sustainable rural enterprise [1]. poultry farmers in the remote rural areas of ghana utilize hatcheries that rely on kerosene or liquefied petroleum gas (lpg), the national grid, or a mix of these as energy sources. these energy sources have high potential to cause fires and also emit exhaust gases that are poisonous to eggs, poultry, and poultry farmers alike [2]. in the case of farmers who utilize diesel-fired incubators, the cost involved is quite high due to the relatively longer distances over which the diesel fuel has to be transported as well as the bad nature of the roads. therefore, the need to adopt a more sustainable energy supply, which is cost-effective and environmentally friendly for efficient performance and productivity is very important. aside ensuring sustainability of energy supply, it is also important to develop an incubator that supplies the optimum chamber conditions required for efficient operation, resulting in an output that yields high returns. incubator chamber temperature and about:blank https://doi.org/10.30772/qjes.v15i2.821 about:blank 114 andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 humidity are known to have a strong influence on the effectiveness of incubation. during the incubation process, eggshell temperature has been shown to be the result of the balance between (a) the transfer of heat to and from the embryo, and (b) embryo heat production. it has been reported that when either heat transfer or heat production is altered, embryo temperature changes [3]. heat transfer has been shown to be mainly determined by the temperature difference between the egg and its environment and air velocity across the egg, and to a lesser extent by humidity of the air [4, 5, 6]. as a result of the effects of temperature and humidity fluctuations on the efficacy of hatching, the incubator hardware must be designed giving utmost care to the balance between the heat and humidity supply rates that will guarantee optimum performance. the general goal of this study is to design and construct a solar-powered guinea fowl egg incubator out of readily available local materials and to assess its performance and suitability for use by small-holder rural poultry farmers in ghana. most significantly, the study seeks to optimize the process of hatching eggs by storing surplus solar energy collected during the day for use at night, as well as creating a pollution-free atmosphere conducive to egg incubation. the outcome of the study will aid in addressing the country's protein requirements more quickly. it will also encourage young people to get involved in small-scale and large-scale poultry farming. 1.2 related l\literature in recent years, several attempts have been made to improve the design of the poultry egg incubator in order to make it less expensive, efficient and environmentally friendly because of high demand and global awareness on issues pertaining to the environment. electro-mechanical improvements permitted the progress from natural breeding to enormous hatching machines and incubators, which resulted in high-capacity incubators suitable for industrial grade production. on the other hand, this hatching shift resulted in increased expenses including energy and water cost [7]. temperature, humidity, and ventilation are key factors in artificial egg incubation. temperature control is critical during incubation with the acceptable range being 35 °c and 39 °c. at extreme temperatures beyond this range, the eggs rarely hatch. if the incubator operates at 40℃ for 15 minutes, the embryos are seriously affected whereas operating at 35℃ for about 4 hours will slow the metabolic rate of the chicks [8]. it is important to maintain a steady metabolic rate. this means that humidity outside of a very limited range has the potential to alter the number of hatched eggs. for effective and efficient hatching, the ideal humidity range is 50 to 70% [9]. embryos acquire oxygen from the environment and produce greenhouse gases as they develop, hence incubators must have ventilation capabilities. incubators with large quantities of eggs and older embryos require a greater amount of air to keep the eggs alive [10]. nomenclature: greek symbols qg total quantity of heat transmitted (j) τ transmissivity of glass ag glass surface area (m 2)  absorptance of solar collector ig total solar irradiance on the glass(kw/m 2) t time (s) cp specific heat capacity of water ( kj/kg ℃) subscripts ∆t temperature difference (℃) g glass qlsc heat loss through the walls (j) w water rt total resistance (m 2. k/w) ic incubating chamber xw kf hic titm tic atm qui qa ma cpa ρa apvc dv fr ta tc it ut qe me ce k1 k2 hi ho thickness of alucobond (m) thermal conductivity of polystyrene (w/m. k) radiation heat transfer coefficient (w/m2. k) inner surface temperature of thermal mass (℃) incubating chamber temperature (℃) area of thermal mass (m2) useful energy delivered to the incubating chamber (j) quantity of heat in air (j) mass flow rate of air (kg/hr) specific heat capacity of air (j/kg. ℃) density of air (kg/m3) cross sectional area of copper pipe trough (m2) depth of inlet opening to incubating area (m2) froude number ambient temperature (℃) collector temperature (℃) solar irradiance (w/m2) overall heat loss coefficient (w/m2. k) heat requirement of egg (j) mass of air (kg) specific heat capacity of egg (j/kg. ℃) thermal conductivity of alucobond (w/m. k) thermal conductivity of polystyrene (w/m. k) inner fluid convective heat transfer coefficient (w/m2. k) outer fluid convective heat transfer coefficient (w/m2. k) itm e f inner thermal mass egg fan andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 115 incubators that operate on grid electricity are very efficient. however, most poultry farmers are located in remote rural communities which have no access to the national electricity grid and operate their farms with bush lamps for heat, which leads to health and environmental hazards characterized by infections and high mortality rates. this results in low productivity in the poultry industry. to remedy the situation, there is the need for other alternative sources of energy. solar energy has become favorable due to its low ghg emission potential coupled with the fact that it is cheap and readily available. this energy can be harnessed using solar panels placed on rooftops, solar farms, and other land areas [11]. some research studies have been carried out to improve poultry production using solar irradiance as the source of energy. mansaray and yansaneh [12] designed, fabricated and tested a solar photovoltaic powered chicken egg incubator. they obtained fertility rate and hatchability of 43.3% and 23.1%, respectively. uzodinma et al. [13] used a phase change material as heat storage in a hybrid solar poultry egg incubator. the average rate of hatched eggs observed was about 63%. ahiaba et al [14] worked on passive solar for incubating poultry chicks. the results of their research showed that poultry production is sustainable with the application of solar energy. this study focuses on the design, construction and testing of a novel solarpowered guinea fowl incubator for subsequent development for commercial purposes. the design uses water as a heat storage medium, incorporates a backup heater and a feedback control system to achieve the right conditions needed for effective hatching. 2. materials and methods 2.1. development of prototype the fabrication and testing of the incubator studied in this work was done at the laboratory of the department of mechanical engineering at the kwame nkrumah university of science and technology, kumasi (6.673175, -1.565423). figures 1a and 1b show the isometric and exploded views of the proposed design, respectively. the incubator body unit was constructed with a bonded (alucobond) material made of aluminum and plastic. a polystyrene (foam) material was used as an insulating material and placed between the two alucobond to reduce heat loss by conduction. the incubation chamber was further galvanized with thin aluminum foil to reduce heat losses across the wall. the incubator size was largely influenced by the size of the egg trays which were the frame on which the eggs due for incubation are mounted. there were two trays with a capacity of 30 eggs each. these egg trays are held by a frame that allows 45-degree rotation in both clockwise and anticlockwise directions. this rotation is made manually possible or by a motor that is coupled to the lower rotating shaft of the frame using a belt and pulley/ chain and sprocket system. the water storage tank is made from a galvanized plate which serves as heat storage or sink for the incubating system both during the day and night. it also served as the storage for the heating medium through which solar energy is harnessed. the solar collector consists of an outer casing made of thick plywood (at the base and sides) covered with transparent glass on top and a copper pipe coiled to form a channel through which the water is held. there exists a circulating fan to draw heat from the collector unit and circulate it through the incubation chamber as well as expelling excessive warm air out. the pronem mini pmi-p digital temperature and humidity controller was used to control the heater and fan to ensure that the right conditions of temperature, humidity, and ventilation are maintained in the system. the fan is also turned on or off by the controller to draw in fresh air to ensure proper ventilation and humidification. a bowl filled with 1.5 liters of water was placed in the incubator on day one and 0.2 or 0.25 liters of water was added as needed depending on the temperature of the day. adding the 1.5 liters on the first day and the rest of the 25 days with an average of 0.2 liters or 0.25 liters results in 7.1 liters for the entire duration of the test. figure 1a. isometric view of the selected concept figure 1b. isometric view of the selected concept 2.1.1 description of incubator heating cycle 116 andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 solar radiation absorbed by the thermal mass (i.e., water) is the primary source of energy to the incubator. a fan installed in the wall that separates the collector chamber and the incubator chamber draws air over the thermal mass and causes the warm air to flow through the incubator chamber, providing the desired chamber temperature for hatching. a close-loop temperature and humidity sensor installed in the incubator chamber ensures that the chamber temperature and humidity are kept within the desired ranges of 35 to 39 ℃ and 50% and 70%, respectively. in the case of undesirable temperature drops in the night as a result of depleting thermal energy reserves a halogen lamp integrated into the incubator design serves as a backup heater to restore chamber temperatures to desired values (see figure 2 for details). figure 2. heating cycle of incubator 2.2. system design the total quantity of heat transmitted to the water in the collector tubes over a period of time, t, is given by 𝑄𝑔 = 𝐴𝑔 × 𝐼𝑔 × 𝑡 × 𝜏 (1) where: 𝐴𝑔 = glass surface area (m 2), (0.4 ×0.4 = 0.16 m2) 𝐼𝑔 = total solar irradiance on the glass, (5.1 kw/m 2-day for the location under study) being the average solar irradiance in accra τ = the transmissivity of glass (i.e., 0.89, this case). the heat collected by water in the storage tank is given by. 𝑄𝑤 = 𝑉𝑤 × 𝜌𝑤 × 𝐶𝑝 × ∆𝑇 (2) where: 𝑄𝑤 = heat accumulated by water 𝑉𝑤 = volume of water used in the tank (π×𝑟 2 × ℎ = 3.142×0.192 ×0.72 = 0.0817 m3) 𝜌𝑤 = density of water (1000 kg/m 3) 𝐶𝑝 = specific heat capacity of water (4.18 kj/kg ℃) ∆𝑇 = temperature difference between the heat collector and the ambient (i.e., about 42 – 32 ℃) hence, the total useful energy delivered to the incubating chamber from the heat storage medium, 𝑄𝑢𝑠 = 𝑄𝑔 − 𝑄𝑙𝑠𝑐 (3) where: 𝑄𝑔 = total energy absorbed by collector. 𝑄𝑙𝑠𝑐 = heat loss through the walls of the storage chamber. (4) and (5) where: 𝑅𝑇 = the total resistance (r-value) of alucobond and polystyrene (insulating material) that made up the wall system. 𝑥𝑤 = thickness of the alucobond (0.004 m) 𝑥𝑓 = thickness of the polystyrene (0.05 m) 𝑘𝑤 = thermal conductivity of the alucobond (0.29 w/mk) 𝑘𝑓 = thermal conductivity of the polystyrene (0.043 w/mk) useful energy delivered to the incubating chamber is determined by: 𝑄𝑢𝑖 = 𝑄𝑤 + 𝑄𝑎 (6) 𝑄𝑤 = (ℎ𝑖𝑐 × 𝐴𝑡𝑚(𝑇𝑖𝑡𝑚 − 𝑇𝑖𝑐 )) (7) where: 𝑄𝑤 = direct heat dissipation from the thermal mass (water); ℎ𝑖𝑐 = radiation heat transfer coefficient from the inner surface of the thermal mass to the incubating chamber. 𝐴𝑡𝑚 = area covered by the thermal mass; 𝑇𝑖𝑡𝑚 = inner surface temperature of the thermal mass; 𝑇𝑖𝑐 = incubating chamber temperature. 𝑄𝑎 = 2ḿ𝐶𝑝𝑎 (𝑇ℎ𝑎𝑐 − 𝑇𝑖𝑐 ) (8) where: ḿa = mass flow rate of air (kg/hr) 𝐶𝑝𝑎 = specific heat capacity of air (kj/kg. oc); but, �̇�𝑎 = 𝜌𝑎 × 𝐴𝑝𝑣𝑐 𝐹𝑟 × √ 𝑔×𝐷𝑣 ×(𝑇ℎ𝑎 −𝑇𝑖𝑐 ) 𝑇ℎ𝑎𝑐 + 𝑇𝑖𝑐 (9) where, 𝜌𝑎 = density of air, kg m -3 ; 𝐴𝑝𝑣𝑐 = cross sectional area of the copper pipe trough, m2; 𝐷𝑣 = depth of inlet opening to incubating chamber; fr = froude number andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 117 equations (8 and 9) are as provided by [15] and [16] respectively. the collector heat removal factor which relates the actual useful energy gained by the collector to the useful energy gained by the air is given by, 𝐹 = �̇�𝑎 𝐶𝑝𝑎(𝑇𝑐−𝑇𝑎) 𝐴𝑐[∝×𝜏×𝐼𝑡 −𝑈𝑡 (𝑇𝑐−𝑇𝑎)] (10) where: 𝑇𝑐 = collector temperature; 𝑇𝑎 = ambient temperature; 𝐴𝑐 = area of collector, 𝛼 = absorptance of solar collector; 𝐼𝑡 = solar irradiance; 𝑈𝑡 = overall heat loss coefficient. the heat absorbed by the air within the incubator to ascend from ambient temperature of 32 oc (as measured), to the incubating temperature of 39 oc was estimated as follows. 𝑄𝑎 = ḿa × 𝐶𝑝𝑎 × ∆𝑇 (11) the heat requirement of eggs is calculated using the equation, 𝑄𝑒 = 𝑚𝑒 × 𝐶𝑒 × ∆𝑇 (12) where: 𝑚𝑒 = mass of egg (kg/hr) 𝐶𝑒 = specific heat capacity of egg (kj kg⁄ . ℃) ∆𝑇 = average temperature difference for eggs, ℃ . heat loss through the walls of the incubating chamber, (13) (14) where: 𝑘1 = thermal conductivity of alucobond (w/mk) 𝑘2 = thermal conductivity of polystyrene (w/mk) ℎ𝑖 = inner convective heat transfer coefficient (inside air) ℎ𝑜 = outer convective heat transfer coefficient (outside air) 𝑥1 = thickness of the alucobond (mm) 𝑥2 = thickness of the polystyrene (mm) the rate at which air is circulated in the incubation chamber is given as; 𝐹𝑓 = 𝐴𝑓 × 𝑁𝑓 (2 × 𝜋 × 𝑟) (15) af = area of fan (0.055 2 × 3.142 = 0.0059 m2 ) nf = speed of fan (1400 rev min⁄ ) r = radius of fan blade (0.055 m) therefore, ff = 0.055 2 × 3.142 × 1400 × 2 × 3.142 × 0.055 = 4.59 m3/min the selected proportional-integral-derivative (pid) controller was used since it is the most widely used temperature control system in the egg incubation industry. the block diagram of the pid controller is shown in figure 3, where kp is the proportional gain, ti is the integral time constant, and td is the derivative time constant. the transfer function of the standard pid algorithm is: (16) in the s-domain, the pid controller can be written as: (17) the discrete form of the pid controller can be achieved by finding the z – transform of equation (17) as: (18) equation (18) can also be written as: (19) where: figure 3a. block diagram of a pid controller figure 3a. block diagram of a pid controller 118 andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 figure 3b. block diagram of the closed loop incubation temperature control system 2.3. test description the solar incubator was constructed and assembled with all other attachments in place. the data on temperature and humidity were monitored and collected with the aid of a data logger and a controller. the data logger was placed inside the incubating chamber closer to the egg trays to monitor and record the incubator chamber temperature and humidity. for the daytime tests conducted, the incident solar radiation intensity was found to be between 680 w/m2 and 870 w/m2 over the test period. the incubator was first tested for three (3) days without load to establish the no-load performance characteristics of the incubator. the incubator was thereafter loaded to a capacity of 30 with guinea fowl eggs. turning of the eggs was carried out at an interval of four (4) hours (four times a day starting from the 2nd day through to the 15th day of incubation test). candling test was also used to check the percentage of fertile eggs and the development of the embryo on the 7th day and 14th days of incubation, respectively. 3. results and discussion figure 4 shows the data obtained from the 72 hours (3 days) of no-load test (i.e., the preliminary test). during the busiest hours of the day, the findings of the performance evaluation done on the incubator in comparison to the benchmark values exhibited some minor deviations. however, the periods in question indicated that as the ambient temperature rises during high solar irradiance hours of the day, the incubator cabinet temperature increased. this temperature disturbance was slightly more than what the controller feed-forward mechanism could handle, which is in the range of plus one (+1 o c) and minus (-1 o c) degrees celsius. this observed anomaly has the capacity to cause irregularities in the incubation rate during peak incubation hours in case the incubator is run with eggs loaded in it. however, amid the observed fluctuations in temperature outside the benchmark range of 35 to 39oc, the rate of incubation would have remained fairly steady. it must be mentioned that the fluctuations in temperature would have been far worse without the use of the automatic control system incorporated into the incubator for regulating incubator cabinet temperature within the required tolerance range. details of temperature and relative humidity variations over the first three days can be seen in figure 4. figure 4. the temperature and humidity variation for no-load test on day one of the test with 30 guinea fowl eggs, the incubation chamber temperature remained within the temperature tolerance range of 4 ℃ (i.e., 35 to 39 ℃) within the first 10 hours and the last 7 hours (i.e., from 17:00 gmt to 24:00 gmt hours from the start of incubation). the deviation outside the temperature tolerance range occurred between the 10 th and the 17th hours with the highest deviation being 3.9 ℃ (i.e., 42.9 -39 = 3.9 ℃) (see figure 5). these deviations, as explained earlier, could be attributed to surges in ambient temperature during hours of significantly high solar irradiance levels. it must be pointed out that long hours of deviation in the temperature tolerance range have the potential to affect the fertility rate hence, the incubation efficiency. the lowest temperature recorded for day 1 was 36oc, the highest was 42.9 ℃ and the average value for the day was 38.27 ℃. the performance of the incubator on day 2 as compared to day 1 is far better with the extent of temperature deviation outside the tolerance range being only 2.2 oc (i.e., 41.2 – 39 = 2.2 oc) as compared with a deviation of 3.9 oc on the 1st day. the slight surge in temperature on day 2 occurred for just 3.5 hours (i.e., between the 12th and 15.5th hours from the start of incubation). the cabinet temperatures were within the required tolerance range between the first 12 hours and the last 8 and half hours. the trial period for day 2 gave the minimum, average, and maximum temperature values of 36 oc, 37.78 oc, and 41.2 oc, respectively. the 3rd day of incubator testing showed incubator cabinet temperatures remaining within the required temperature range of 35 to 39 oc within the first 10 hours of testing and the last 8 hours of testing. the increase in incubator chamber temperature above the upper limit of temperature value (i.e.,39 oc) was only 1.1 oc, which is an appreciable improvement in performance relative to the deviations noted on the first two day of the trial. although the deviation lasted for 5 hours, the marginal nature of the deviation makes the 3rd day of testing the most efficient trial set in terms of incubator cabinet temperature variation. the trial period for day 3 gave the minimum, average, and maximum temperature values of 36 oc, 37.70 oc, and 40.1 oc, respectively. figure 6 shows the variation in relative humidity in the incubator cabinet with respect to time for the three days of testing. the trend of results show that the rh value was within the recommended range of between 50% and 70%. except that the rh variation for day one reached a maximum value of 70.5% after 6 hours of testing. however, rh values normalized afterward and remained within the tolerance range. the minimum and average rh values observed for day 1 were 55% and 59.73% respectively. for day 2 (see figure 6), incubator cabinet relative humidity values remained within the required tolerance range that promotes adequate fertility for incubation. however, the variation in rh values within the range indicated for day 2 was random between the 6th and the 17th hours of testing. but effectively, the rh values remained within the required tolerance range which reveals the effectiveness of the current design in andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 119 maintaining the required humidity levels for adequate fertility and a high incubation rate. the minimum, maximum, and average values of 53%, 65.8%, and 59.10%, respectively. the variation in relative humidity values for day 3 as indicated in figure 6, also exhibits a relatively linear trend as compared with the variations for days 1 and 2, with the minimum and maximum rh values being 55% and 63% and an average value of 59.44% the average rh values of 59.73%, 59.10%, and 59.44% recorded for days 1, 2, and 3 show that the proposed incubator design can effectively maintain the right moisture levels for efficient incubation. figure 5. variation of incubator chamber temperature when loaded with eggs the results obtained during the test show that out of 30 eggs set in the incubator, 18 were fertile (table 2), yielding a percentage fertility of 60%. also, out of 18 fertile eggs, 10 were hatched, giving a percentage hatchability of 56%. the complete system, which consists of the incubation chamber, a temperature controller (pid), a solar collector, an air circulating fan, and a backup heat source, was simulated using matlab/simulink. figure 6. variation of incubation chamber humidity with time when loaded with eggs the incubation system with partial and full control from the pid temperature controller was tuned using the ziegler nichol tuning technique during the simulation to determine the values of the parameters that provided the system the specified transient response when subjected to a unit step input. the system control outcomes with pid tuning were simulated and studied. the incubation system is depicted in simulink block diagrams 7a and 7b. figure 7a. simulink block diagram of the partial incubation temperature control figure 7b. simulink block diagram of the full incubation temperature control table 1 shows the hypothetical values considered for the pid controller parameters and the response of the system to these values. figure 7c is the response of partial pid or p control. from the response, it is obvious that the system was not properly controlled looking at the lack of correlation between the block-response and the tuned-response. this outcome goes to explain why solar irradiation should not be solely relied on during the day, which is likely to under-heat or overheat the system. the graph shown in figure 7d illustrates that the system has improved with complete control of the system by the pid during incubation. this is a speedier reaction than the one depicted in figure 7c. mp, or maximum overshoot, climbed to around 22%. this is still acceptable because it is within the allowed overrun of 25%. the settling time (ts), peak time (tp), and delay time do not change. the new pid/tuned parameters obtained are: kp =1.338, ki =0.02228, and kd = -5.829. 120 andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 table 1. values of the pid temperature control parameters test parameter kp (sec) ki (sec) kd (sec) test 1 values 1 0 0 test 2 values 1 0 0 new values 1.338 0.02228 -5.829 figure 7e response shows that the system has improved comparatively, compared to the situations depicted in figures 7a to 7d. hence, it can be seen that the final parameters are superior to the earlier two responses. however, the setback is the mp, which is the same as the mp of the response in figure 7d. nevertheless, the final response mp is still within the 25% maximum overshoot allowable. candling test was used to track the progress of incubation during the test. this was done by shining a light with intensity of between 400 to 520 w/m2 on an egg in a dark room so that one is able to see what is going on inside the egg. this observation was done throughout the entire duration of the test. figure 7c. unit step response of the system for test 1 in this study, candling was carried out on the 30 loaded eggs on the first (1st), fourth (4th) and seventh (7th) days of incubation. in the end, eighteen (18) eggs were fertile per the test, as indicated in table 2. fertile eggs were identified upon seeing web-like lines and rings running across the egg. the percent fertility and hatchability of the eggs estimated were 50% and 56%, respectively. figure 8a shows an egg placed on a candler before the start of the incubation test. the picture shows a clear and spot-free egg, which is an indication that no embryonic development has begun. figure 7d. unit step response of the system for test 2 figure 7e. unit step of an improved response of the system for test 2 table 2. candling test on the 7th day group number of eggs development observatio n remark 1 7 not visible clear infertile 2 5 not visible large air space (bad eggs) infertile 3 3 visible at the centre visible patches of red strains fertile 4 15 visible at one end lines running across (rings) fertile a blood spot was seen in some of the eggs on the fourth (4th) day of incubation when the candling was done. this blood spot is an indication of fertility as well as embryonic development in eggs as shown in figure 8b. nonetheless, studies such as [17] believe that overheating the eggs is more important than under heating since it accelerates the rate of development, producing aberrant embryo development in the early stages and reducing the hatchability %. meanwhile, running the incubator for at least 15 minutes at 40.5°c is lethal and will severely harm or destroy the embryos [17]. the temperature of the incubator should be kept between 35 and 39 degrees celsius. andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 121 figure 8a. egg positioned on lamp in preparation for candling test (day one) if the temperature dips below 35 oc or climbs above 39 oc for several hours, death occurs. hence, it is evident per experimental observations in this study that the 30 eggs used for the testing experienced some overheating during the peak hours of the day. figure 8b. candled egg on day four figure 8c. candled egg on day seven in machine design, the principal aim is to design a unit that is adequately functional and economically viable. the machine should be standard, safe, and affordable. it is very important to take into consideration existing machines in the market to form a basis for estimation. the materials/instruments, their brief description, their size/capacity, and their cost, and the total price were recorded for the purpose of assessing the economic feasibility of the solar-powered incubator. these include the handling and transportation cost and the labor cost. the total estimated cost of the project is 474.90 usd (at the prevailing bank rate of ghc 7.37 =1 usd as of april 2022). the selling price was determined by putting into consideration the production cost, tax, and suitable profit margin. assuming a profit of 30% of the total production cost, the selling price was determined to be 617.32 usd. assuming that the solar hybrid incubator hatches fifty (50) eggs out of sixty on the average per month; then the benefit for a year on saving for sale of week-old chicks (total revenue) is 976.93 usd. if the expenses per year are assumed to be ghc 488.47, the net profit per year (total revenue – total cost (expenses) will work out to 488.47 usd. hence the payback period will be 1.26 years. figure 9 picture of assembled incubator showing instrumentation 4. conclusion a solar-powered poultry egg incubator was conceived and built utilizing locally accessible materials in this study. the proposed incubator has a solar collector, built-in heat storage, an automated controller, and a 1,130 mm 630 mm 780 mm incubation chamber with a capacity of 60 eggs. the primary goal of this research was to compare the incubation parameters (temperature and humidity) to benchmark values based on the heating mode. this was made possible using the ut330a usb datalogger. the results obtained during the three (3) days of no-load test showed a temperature range of 36 ℃ to 42.9℃ and relative humidity range of 53 % to 70.5 %. the incubation test gave incubation chamber temperature and relative humidity values 35 ℃ to 41 ℃, and 45 % to 61 %, respectively. candling tests gave percentage fertility and hatchability of 60% and 56%, respectively. a cost-benefit analysis gave a capital cost of 617.32 usd, incubation cost of 69 cents per chick and a simple payback period of 15 months. the performance of the proposed incubator shows that the proposed design has great prospects to improve poultry farming and productivity for livelihood empowerment within rural communities in ghana so that the incidence of migration will be curbed among the poor rural communities of ghana. significantly, the study has provided a sound working design for effective hatching of eggs with a notable percentage fertility of 60%. this design serves as a solid basis for further development through optimization studies. it is hoped that future studies will focus on improving the percentage fertility and hatchability to much higher values through a stricter regulation of temperature and relative humidity within the ideal ranges reported in this study. further studies will also explore harnessing excess solar energy during peak sunshine hours of the day (i.e., between 12:00 gmt and 15:00 gmt) and storing it in a phase-change material (pcm) for use during the night. acknowledgements 122 andoh et al. /al-qadisiyah journal for engineering sciences 15 (2022) 113–121 the authors are profoundly grateful to the department of mechanical engineering, knust, kumasi, for making available the mechanical engineering workshop during the fabrication stage of the research. funding this research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors references [1] a.m. kingori, review of the factors that influence egg fertility and hatchability in poultry, international journal of poultry science, 10 (6) (2011) 483-492. [2] w. i. okonkwo, o. c. chukwuezie, characterization of a photovoltaic powered poultry egg incubator, international proceedings of chemical, biological, an d environmental engineering, 47 (2012) 1-18. [3] meijerhof, r. 2002. design and operation of commercial incubators. pages 41–46 in practical aspects of commercial incubation. ratite conference books, lincolnshire, uk. [4] kashkin, v. v. 1961. heat exchange of bird eggs during incubation. biophysics 6:57–63 [5] meijerhof, r., and g. van beek. 1993. mathematical modeling of temperature and moisture loss of hatching eggs. j. theor. biol. 165:27–41. [6] van brecht, a., h. hens, j. l. lemaire, j. m. aerts, p. degraeve, and d. berckmans. 2005. quantification of the heat exchange of chicken eggs. poult. sci. 84:353–361. [7] r.t. wilson, poultry production and performance in the federal democratic republic of ethiopia, world's poultry science journal, 66 (3) (2010) 441-444. 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[13] e. o. uzodinma, o. ojike, u. j. etoamaihe, w. i. okonkwo, performance study of a solar poultry egg incubator with phase change heat storage subsystem, case studies in thermal engineering, 18 (2020), 100593. [14] u.n. ahiaba, u.v. theresa, s.e. obetta, development and evaluation of a passive solar powered system for poultry egg incubation. international journal of engineering research and general science, 3 (2015), 748-760. [15] n.k. bansal, b.c. gour, application of u and g values for sizing passive heating concepts, solar energy 57(5):361–373, 1996. [16] zriken, z. and bilgen, f. “theoretical study of a composite trombe’. michael wall solar collector system. canada. 39(5): 409 – 419. 1987. [17] a. lourens, r. meijerhof, b. kemp, h. van den brand. 2011. energy partitioning during incubation and consequences for embryo temperature: a theoretical approach. poultry science 90 :516–523. doi: 10.3382/ps.2010-00928 about:blank about:blank article al-qadisiyah journalforengineering sciences15 (2022) 048–054 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author: eng.chem.20.post.5@qu.edu.iq (zahraa alaa) https://doi.org/10.30772/qjes.v15i1.813 2411-7773/©2022university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. effect of mono and bipolar connection modes on the electrocoagulation removal efficiency of multi-heavy metals from simulated wastewater zahraa alaa hawass*a and forat yasir aljaberi b adepartment of chemical engineering, college of engineering, the university of al-qadisiyah, al-qadisiyah, iraq. bdepartment of chemical engineering, college of engineering, al-muthanna university, al-muthanna, iraq. a r t i c l e i n f o article history: received 10 may 2022 received in revised form 5 june 2022 accepted 26 july 2022 keywords: electrocoagulation reactor monopolar bipolar heavy metals energy electrodes consumption a b s t r a c t electrochemical treatment methods are frequently used to remove a wide range of pollutants from wastewaters generated by domestic and industrial operations. this work aims to investigate the impacts of using monopolar and bipolar connection modes of an electrocoagulation reactor (ecr) used to remove multi-toxic metals from synthetic wastewater. the present design of the ecr involves concentric-multicubic (cmc) aluminum electrodes with an activated area of 360 cm2. the anode electrodes are perforated to be light-weight and decrease the amount of anode consumption as well as the increase of oxygen bubbles released that were assisting the buoyancy process of light-pollutants toward the surface of the solution in addition to the hydrogen bubbles are released from the plane electrodes of the cathode. the synthetic wastewater contains 100 ppm of each pb, cd, and cu ion under the effects of ph of 7, applied current of 1.4 a (which equals remove to 3.88 ma/cm2), nacl of 2 g, 300 rpm of stirring speed, and reaction time of (0-90 min). the core results proved that the bipolar connection mode (bcm) was more effective than the monopolar connection mode (mcm) in toxic metal-wastewater treatment. after 60 min of the reaction time, the highest removal efficiencies of these metals after a reaction timeof 60 min, the highest removal efficiencies of pb, cd, and cu metals obtained via the bcm system were : 99.91%, 99.68%, and 99.14%, respectively 99.91%, 99.68%, and 99.14%, respectively. while they achieved 60.55%, 64.24%, and 89.55% via the mcm system , . re spectively the present new design of electrodes using the bipolar system was more reliable in wastewater treatment containing toxic metals with significantly low values of electrical energy consumption, electrode consumption, and cost-effectiveness ©2022university of al-qadisiyah. all rights reserved. 1. introduction in the modern world, large amounts of wastewater are discharged from industrial activities to the environment containing several types of pollutants that can be classified as degradable or non-degradable pollutants[1-3]. domestic wastewater contains various organic materials and inorganic materials [4]. industrial polluted water contains several types of toxic pollutants such as cyanide, pesticides, and heavy metals . metals with a specific gravity greater than five are classified as heavy metals such as lead, cadmium, zinc, chromium, copper, and mercury [5]. excessive use of water results in the production of large quantities of wastewater laden with impurities in the water system and must then be treated through treatment processes. the industrial activities in iraq, such as the petrochemical and chemical industries, in 2014 alone consumed more than (44,300) cubic meters of fresh water per day and produced more than (17,500) cubic meters of polluted water per day which contain different http://qu.edu.iq/ mailto:eng.chem.20.post.5@qu.edu.iq https://doi.org/10.30772/qjes.v15i1.813 https://doi.org/10.30772/qjes.v15i1.813 http://creativecommons.org/licenses/by/4.0/ zahraa alaa hawass and forat yasir aljaberi author /al-qadisiyah journalfor engineering sciences 15 (2022) 048–054 49 organic and inorganic pollutants [6]. one of the most important resources is water.. as a result of the great industrial development, the increase in the population and the use of water in various matters, such as in homes and industries [7]. there fore , wastewater must be treated and pollutants removed for economical and environmental development [8], using effective methods such as chemical precipitation [9] ,ion exchange[10], adsorption [11], membrane filtration [12], nanomaterial [13], and electrocoagulation [14]. during the last twenty years, electrochemical technologies are developed in water and wastewater treatment with higher efficiency than other conventional methods because of their ecofriendliness by controlling pollution, versatility through the flexibility to treat a spread of pollutants via redox reactions, energy efficiency due to the minimizing of non-homogeneously in current applied distribution then the drop, safety, selectivity, and price effectiveness. moreover, electrochemical technologies are simple, easily operable, and low amount of sludge produced without the generation of secondary pollution. electrocoagulation is a distinct process based on the concept of (electrochemistry) using electric current to remove toxic metals from solutions containing waste discharged from various industrial uses such as metal plating wastewater [15], oily wastewater [16], polluted groundwater [17], wastewater from paper industries [18], olive millswastewater[19],municipal waste water [20] , etc .electrocoagulation (ec) is one of the emerging processes for heavy metal-contaminated wastewater treatment [1] . the ec method is more economical and reliable when compared to other treatment techniques. (for its ability to make many contributions to the environmental treatment, recycling and ,control [2123], fig. 1. figure 1. general schematic of electrocoagulation technique (aljaberi, 2022) the chemical reactions proceed in the ec reactor are shown in the follwing eqs. 1 to 3, [23]: al(s) al3+ (aq) + 3e at the anode (1) 2h2o + 2e-h2(g) + 2oh (aq) at the cathode (2) al3+ +3ohal(oh)3 formation of coagulants (3) several studies have used electrocoagulation method to remove heavy metals from wastewater by performing different configurations of electrodes.abdulrehman, et al. (2015), [24] used bipolar aluminum electrodes in a batch electrocoagulation reactor to remove heavy metals such as lead from wastewater under the effect of the electrolysis, current density (,33 a/m2) and ,reaction time(30min), lead concentrations (515ppm), and solution ph (7)achieving 94% of lead removal efficiency. abdul rehman, et al. used iron and aluminum plane-electrodes in a bipolar connecting mode to remove (105 ppm ni ion,110 ppm cu ion, and 63 ppm pb ion) in a continuous electrocoagulation system under the impact of ph (3-9), inter-electrode spacing (4-24mm), hydraulic retention time (2012sec.), and current density (0.007-0.04)a/cm2. , optimal experimental conditions (actual ph 6.32, current density 0.026 a cm-2), the removal efficiency of heavy metals from artificial wastewater was higher than 95 % bernard, et al. (2013) [25] investigated the ability of an ec for simultaneous ni, zn, and mn removal from sewage wastewater utilizing monopolar iron electrodes. the experiments were done under the impact of current density (from 2 to 25 ma/cm2) , initial ph (3, 5.68, 8.95) and initial metal concentration (50 to 250 mg/l) . they found that higher ph levels are more suitable for metal removal by ec treatment. except for mn, which obtained a 72.6 percent removal value at a current density of 25 ma/cm2 and a total energy usage of 49 kwh/m3, all metals investigated achieved better than 96 percent removal efficiency1 . tubular and finned shapes of electrodes are invented and performed in previous studies such as [26-27] in wastewater treatment. this study aims to investigate the ability of a new configuration of ec reactor involving concentric-cubic-electrodes on the removal efficiency of multi-heavy metals from synthetic wastewater via the compare is on between two connection modes which were the bipolar connection mode (bcm) and the monopolar connection mode (mcm). the operational parameters studied were the initial concentrations of pb, cd, and cu metals, ph, reaction time, applied current, nacl concentration, and the stirring speed. the anode electrodes are designed as perforated shapes to be lightweight and to decrease the amount of anode consumption as well as the increase of oxygen bubbles released that were assisting the buoyancy process. 2. experimental work 2.1. apparatus a 3 liter glass batch ec reactor was used to conduct the present experiments (figures 2). it consists of four concentric aluminum cubes with different dimensions but the same thicknesses as given intable1 with an active area of approximately (360 cm2). the ec cell was connected to a dc digital power supply (model: syadgong-305d company, china) to provide the designed current. a constant mixing speed of 300 rpm was provided by using a magnetic stirrer (model: alfa company, iran: d-500; 100–1,800 rpm). the value of solution ph was measured by using an electronic ph meter (model: atc company, china), [28]. the concentric cubic electrodes were aluminum containing two perforated anodes and two nonperforated cathodes, fig. 3. table 1. the dimensions of the perforated (p) and non-perforated (np) electrodes no. anode/ cathod e p or np dimensions (cm) electrode thick (cm) electrode distance (cm) wet height (cm) 1 anode p 4 × 4 × 10 0.2 2 4 2 cathod e np 8 × 8 × 10 0.2 2 4 3 anode p 12 × 12 × 10 0.2 2 4 4 cathod e np 16 × 16 × 10 0.2 2 4 50 zahraa alaa hawass and forat yasir aljaberi author /al-qadisiyah journalfor engineering sciences 15 (2022) 048–054 figure. 2. the schematic of the present ec reactor figure.3. the configuration of the cubic electrodes table 2. the values of experimental parameters parameters values pb ions (ppm) 100 cd ions (ppm) 100 cu ions (ppm) 100 ph 7 current (aor ma/cm2) 1.4or 3.88 nacl (g) 2 stirring speed (rpm) 300 reaction time (min) 0-90 this study compared the ability of these electrodes in wastewater treatment between two operating systems which are the bipolar connection mode (bcm) and the monopolar connection mode (mcm). for the most part, electrochemical investigations have been used to investigate the operational parameters of this work.. their values (table 2) are selected based on a previous review paper [29]. 2.2. materials a 2.5 liter synthetic wastewater was prepared by dissolving the required weights of pb, cd, and cu salts in distilled water. the nacl electrolyte was added to raise the electrical conductivity of the solution and prevent the passivation, i.e. the formation of an oxide layer, on the electrodes. the required ph value was adjusted using naoh (0.1 n) and hcl (0.1 n). when the electrodes immersed were in the simulated wastewater, the dc-current of 1.4 a(3.88 ma/cm2) was supplied to the electrochemical cell and the magnetic stirrer was turned on to agitate the solution at (300 rpm). the sampling of each experiment was conducted at the periods of (5, 10, 15, 30, 45, 60, 75, and 90 min). the analysis of the collected samples was done using atomic absorption spectroscopy(model: aa-7000f, shimadzu, japan), [28] to determine the final concentrations of toxic metals present in the treated solution. after each experiment done for each configuration, these electrodes were washedby0.1 n hcl and water to ensure it was cleaned well. the electrical energy consumed by the electrochemical cell is calculated using eq.4 as follows: 𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙 𝐸𝑛𝑒𝑟𝑔𝑦 𝐶𝑜𝑛𝑠𝑢𝑚𝑝𝑡𝑖𝑜𝑛 (𝐸𝐸𝐶) = 𝑈 ×𝐼 ×𝑡 𝑉 (4) where: u is the applied voltage (volt), i is the electric current (a), t is the reaction time (h), and v is the solution volume of the contaminated water (m3). the theoretical consumption of electrodes could be estimated from the following equation (eq. 5): 𝑻𝑬𝑪 = 𝑰 ×𝒕 ×𝑴 𝒁 ×𝑭 (5) where: m is the molecular weight of electrodes metal, z is the electrons number presented in the electrolysis reaction (for al is 3), and f is faraday's constant (96485.34 col/mol).the removal efficiency of each toxic metalis determined using eq. (6): 𝑹𝒆𝒎𝒐𝒗𝒂𝒍𝑬𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 = 𝑪𝟎−𝑪𝒕 𝑪𝟎 × 𝟏𝟎𝟎 (6) where c0 and ct are the initial and final concentration of each metal (ppm). 3. results and discussion the impact of changing the connection mode to the dc-power supply as bcm and mcm using the new configuration of electrodes, i.e. perforated and non-perforated concentric cubic-electrodes, was investigated in multiheavy metals removal from synthetic wastewater under the influences of several parameters that listed in table 2. 3.1. removal efficiency based on the obtained results of the bcm and mcm experiments, the removal efficiencies of pb, cd, and cu ions from simulated wastewater were higher in the case of bcm compared to that obtained in the case of mcm. tables3 to 5 and figures 4 to 6 reveal these findings. table 3. results of bcm and mcm experiments for pb removal efficiency bcm experiment mcm experiment reaction time (min) pb concentration (ppm) bcm-pb removal % pb concentration (ppm) mcm-pb removal % 0 100 0 100 0 5 10.2648 89.7352 88.30 11.696 10 9.2896 90.7104 81.19 18.81 zahraa alaa hawass and forat yasir aljaberi author /al-qadisiyah journalfor engineering sciences 15 (2022) 048–054 51 15 1.1035 98.8965 74.63 25.373 30 0.4106 99.5894 52.70 47.296 45 0.0257 99.9743 33.21 66.789 60 0.0924 99.9076 39.45 60.553 75 0.231 99.769 33.67 66.327 90 0.1386 99.8614 20.28 79.722 figure 4. bcm and mcm removal of 100 ppm pb ions from simulated wastewater figure 5. bcm and mcm removal of 100 ppm cd ions from simulated wastewater figure 6. bcm and mcm removal of 100 ppm cu ions from simulated wastewater table 4. results of bcm and mcm experiments for cd removal efficiency bcm experiment mcm experiment reaction time (min) cd concentration (ppm) bcm-cd removal % cd concentration (ppm) mcm-cd removal % 0 100 0 100 0 5 47.785 52.215 40.9508 59.0492 10 36.431 63.569 41.0118 58.9882 15 31.2819 68.7181 39.8344 60.1656 30 4.1664 95.8336 38.3399 61.6601 45 0.3843 99.6157 36.9511 63.0489 60 0.3213 99.6787 35.7615 64.2385 75 0.4555 99.5445 26.9996 73.0004 90 0.002 99.998 14.8073 85.1927 table 5. results of bcm and mcm experiments for cu removal efficiency bcm experiment mcm experiment reaction time (min) cu concentration (ppm) bcm-cu removal % cu concentration (ppm) mcm-cu removal % 0 100 0 100 0 5 5.2944 94.7056 10.309 89.691 10 2.3296 97.6704 4.8255 95.1745 15 0.8547 99.1453 4.47 95.53 30 0.2798 99.7202 4.175 95.825 45 0.3857 99.6143 8.9778 91.0222 60 0.8547 99.1453 10.4452 89.5548 75 1.195 98.805 13.2134 86.7866 90 0.4614 99.5386 10.846 89.154 as revealed that the removal efficiencies of heavy metals were improved when the concentric cubic-electrodes were arranged as bipolar connection mode (bcm) compared to those of the monopolar connection mode (mcm). after a reaction time of 60 min, the highest removal efficiencies of pb, cd, and cu metals obtained via the bcm system were : 99.91%, 99.68%, and 99.14%, respectively. while they achieved 60.55%, 64.24%, and 89.55% via the mcm system, respectively .these results were agreed with [30-31]. 3.2. electrical energy consumption this is an effective parameter in wastewater treatment when any type of electrochemical technology is performed. table 6 and figure7 list the value of eec (eq. (1)) at the highest removal efficiency for each metal using bcm and mcm configuration systems. as observed that the total energy consumption of the bcm system is less than of the mcm system. the new configuration of the present electrodes assists the performance of the electrocoagulation reactor by minimizing the consumption of the electrical energy [32]. 52 zahraa alaa hawass and forat yasir aljaberi author /al-qadisiyah journalfor engineering sciences 15 (2022) 048–054 table 6. energy consumption for each metal using bcm and mcm systems heav y metal s bcm system mcm system reactio n time (min) remova l % eec (wh/m3 ) reactio n time (min) remova l % eec (wh/m3 ) pb 45 99.974 12.6 90 79.722 25.2 cd 90 99.998 25.2 90 85.193 25.2 cu 30 99.720 8.4 30 95.825 8.4 figure 7. energy consumption via the bcm and mcm system to remove multi-heavy metals from simulated wastewater 3.3. theoretical electrodes consumption table 7 and figure8 explain the amounts of the theoretical consumption of electrodes measured in (gram) using eq. (2) via both systems of bcm and mcm. the core findings proved that the total consumption of electrodes was higher through the mcm system compared to that measured via the bcmsystem. in general, the small amount of electrodes consumption observed is due to the new configuration of perforated electrodes of the anode. this observation is similar to that found by [33] was 0.23 g for bcm system and 0.58 g for the mcm system which means that the bcm is costeffective. table 7. electrodes consumption for each metal using bcm and mcm systems heavy metals bcm system mcm system reaction time (min) removal % tec (g) reaction time (min) removal % tec (g) pb ions 45 99.974 0.352 90 79.722 0.705 cd ions 90 99.998 0.705 90 85.193 0.705 cu ions 30 99.720 0.235 30 95.825 0.235 figure 7. electrodes consumption via the bcm and mcm systems to remove multi-heavy metals from simulated wastewater as observed that the bipolar connection mode (bcm) is more effective than the mono-polar connection mode to remove pb, cd, and cu ions from synthetic wastewater with low values of electrodes and energy consumption. table 8 lists a summary of some previous studies which investigated the ability of electrocoagulation technology in wastewater treatment using bipolar and monopolar connection modes. table 8. summary of some previous studies used that electrocoagulation removal of multi-heavy metals from wastewater references pollutants bcm or mcm removal efficiency% ahmad1, et al. [34] cu and zn bcm 96% c. escobara cu, pb, and cd mcm 80 u. t.un et al. [35] cd, cu, and ni bcm 98 a.rehman [31] cu, ni, and pb bcm 95 al aji, et al. [34] cu, ni, zn, and mn mcm 96 present study pb, cd, and cu bcm >99 3.4. simplified kinetic approach in general, the order of any reaction is based on several conditions such as the stoichiometry of the chemical reaction equation which is corresponded or does not with the rate equation.there fore, the order of reaction throughout every reactor should be studied. the kinetic modeling for the effective configuration (i.e., bcm) is provided to estimate the reaction rate constants of the electrocoagulation process. eq. 7 shows the general rate equation that represents the removal rate of each metal: 𝑑𝐶𝑡 𝑑𝑡 = −𝑘𝐶𝑡 𝑛 (7) where c is the concentration of each metal, k is the rate constant,n is the reaction’s order, and t is the reaction time. table 9 lists the summary of the kinetic study for each heavy metals throughout the electrocoagulation reactor using the effective configuration of electrodes, i.e. bcm system. 0 5 10 15 20 25 30 pb ions cd ions cu ions bcm-eec (kwh/m3) 0 0.2 0.4 0.6 0.8 pb ions cd ions cu ions bcm-tec (g) mcm-tec (g) zahraa alaa hawass and forat yasir aljaberi author /al-qadisiyah journalfor engineering sciences 15 (2022) 048–054 53 table 9. summery of the kinetic study heavy metals reaction order general equations simulated equations k(mol/m3)1n r2 pb 1 -ln(ct/ci)=k1t y = 0.1731x + 0.8536 0.1731 0.864 2 (1/ct)(1/ci)=k2t y = 20.592x 111.63 20.592 0.842 cd 1 -ln(ct/ci)=k1t y = 0.101x + 0.0063 0.1010 0.964 2 (1/ct)(1/ci)=k2t y = 0.1951x 1.1432 0.1951 0.776 cu 1 -ln(ct/ci)=k1t y = 0.3021x + 0.5989 0.3021 0.905 2 (1/ct)(1/ci)=k2t y = 6.4166x – 20.00 6.4166 0.635 as revealed in table 9 that all heavy metals in this work obeyed in their behavior the first order reaction with the highest values of the regression coefficient (r2) for each. the new design provides an additional advantage as pb, cd, and cu removal from wastewater via a first order reaction which is fastest than the second-order reaction. 4. conclusions this study investigated the ability of an electrocoagulation reactor involving a new configuration of electrodes to remove multi-toxic metals from synthetic wastewater. four concentric-cubic electrodes made of aluminum were performed as two-perforated anodes and two-nonperforated cathodes. a comparison of two connection modes (bipolar and monopolar, i.e. bcm and mcm) to the dc-power supply was conducted .the main conclusion points are listed below: 1. the new configuration of electrodes is significantly enhancing the electrocoagulation reactor efficiency. 2. the bcmconfiguration is more effective than cmc the configuration in removing pb, cd, and cu from synthetic wastewater. 3. the bcm system consumes a low electrical energy compared to that observed by the mcm system. 4. the bcm system consumes a low theoretical consumption of electrodes compared to that of the mcm system. references [1] a. abdul majeed1and maitham adham zubaidy2, performance study of electrodialysis for treatment fuel washing wastewater, iraqi journal of chemical and petroleum engineering, vol.17no.4(december2016) 35 -42issn: 1997-4884. 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[35] walsh, f. c., 2001, electrochemical technology for environmental treatment and clean energy conversion, pure appl. chem., vol. 73, no. 12, pp. 1819 1837 [36] z . al-qodah,m. al-shannag, heavy metal ions removal from wastewater using electrocoagulation processes: a comprehensive review, separation science and technology · september 2017 doi: 10.1080/01496395.2017.1373677 403 forbidden<br> article al-qadisiyah journal for engineering sciences 15 (2022) 181–186 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes *corresponding author. e-mail address: edi.yusuf@eng.unri.ac.id (edi yusuf adiman) https://doi.org/10.30772/qjes.v15i3.831 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. effect of water immersion on the ac-wc mixture utilizing elastomeric modified asphalt to compressive strength, elastic modulus and durability edi yusuf adimana*and latif budi suparmab adepartment of civil engineering, riau university, indonesia. bdepartment of civil and environmental engineering, gadjah mada university, indonesia. a r t i c l e i n f o article history: received 24 july 2022 received in revised form 20 august 2022 accepted 28 september 2022 keywords: durability compressive strength elastic modulus ac-wc elastomeric modified asphalt a b s t r a c t indonesia has relatively high rainfall with a long duration of rain. it can result in a flood on the surface of the road. a flood can reduce the strength of materials from the asphalt mixture and cut the life of the road plan. therefore, it is necessary to conduct a study that can measure the durability level of the asphalt material mixture on the surface layer of the road to the flood water bath. the study used an asphalt concrete-wearing course (ac-wc) mixture with elastomeric modified asphalt (ema), and an upper limit (ul), middle range (mr), and lower limit (ll) gradation based on specification. the optimum bitumen content (obc) value was obtained from each gradation by applying the marshall test. the value of the obc was used to create specimens that had a diameter of 3 inches and a height of 6 inches, and they were using an unconfined compression strength (ucs) test. this study measures the durability of compressive strength and elastic modulus from a mixture of flood water immersion for 1, 2, 4, and 7 days. to calculate the durability using retained strength index (rsi), first durability index (r), and second durability index (a). the results showed that there was a decrease in the compressive strength of the mixture on gradations of ul, mr, and ll on days 1, 2, 4, and 7. it meant that the longer the immersion time more reduced the compressive strength of the mixture. the ul-gradedraded mixture had the best durability when it was compared to the mr and ll gradations up to the 7th-day immersion, with an rsi of 91.19%, (r) of 7.44%, and (a) of 6.93%. at the same time, in the elastic modulus of the mixture, there was no significant effect on the duration of immersion because it had a fluctuating value of the elastic modulus to the duration of immersion. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction indonesia belongs to a tropical country which has a relatively high rainfall with long duration of rain. it can result in puddles (flood) in the surface of the road. flood can cause road damage because water can loosen the bond between the aggregate and the asphalt. when asphalt and aggregate bonds are loosened by water, passing vehicles will carry a cracking load or other road damage that may reduce the life of the road plan. asphalt concrete is a mixture that comprises hard asphalt as a binder and coarse with fine and filler aggregates, by mixing and compacting under certain heat and temperature conditions [1]. the asphalt concrete into 3 different mixtures: asphalt concrete wearing course (ac-wc), the asphalt concrete binder course (ac-bc) and asphalt concrete base course (ac-base), with the maximum aggregate size of each mixture is 19 mm, http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i3.831 https://doi.org/10.30772/qjes.v15i3.831 http://creativecommons.org/licenses/by/4.0/ 182 edi yusuf adiman and latif budi suparma /al-qadisiyah journal for engineering sciences 15 (2022) 181–186 25.4 mm and 37.5 mm, respectively [2]. based on [3], aggregates are grouped into : course aggregate; that is an aggregate retained sieve no.4 (4.75 mm), fine aggregate; that is an aggregate that passes the no.4 (4.75 mm) sieve and the filler; that is a part of the fine aggregate that passes no. 200 (0.075 mm). asphalt modification is a conventional asphalt which is modified by the addition of additives on conventional asphalt. [3] says that asphalt modification includes latex or synthetic asbuton and elastomeric. added polymer type is often used in the manufacture of pavement as an asphalt modifier. polymers are generally divided into two categories: plastomers and elastomers, in which elastomers are polymers of an elastic nature, when pulled, the voltage is given back to its original state. one of the major roles of elastomeric modified asphalt (ema) in asphalt mixture is to increase asphalt resistance to permanent deformation at high temperature without harming bitumen or bitumen properties. as a result, polymer asphalt has high resistance to deformation and crack damage. the use of polymer modified asphalt polymer (ema) on the surface layer (acwc) is expected to improve the performance of the mixture as well as the quality of the binder asphalt. the durability test based on sni m-58-1990 only measures the level of mixture durability with water immersion to its stability value only, whereas durability can be seen from the compressive strength and elastic modulus. [4] and [5] in his research say that the use of immersion using the type of flood water has a lower durability value compared with laboratory water. this is due to the dissolved content (mud particles) contained in the flood water is greater than the laboratory water. the mastic layer on the asphalt mixture becomes easily eroded by the sludge contained in the flood waters through the advective transport process. on a road pavement, the compressive strength can be represented as the maximum strength of the mixture in receiving the direct load from the vehicle, while the elastic modulus is the value of the stiffness of the mixture itself. [6] states that in order to know the compressive strength of a material, it is necessary to compress the press compression to understand the compressive strength of a material in order to know the reasonable limits of loading. [7] conducted a study to see the stress-strain relationship on asphalt concrete using pressure. the results of his research on asphalt concrete specimens with aggregates, compaction efforts, asphalt percentages, different size and type of loading exhibited a pattern similar to the stress-strain relationship commonly used on cement concrete. his research also found that there was a linear relationship between the modulus of elasticity and its compressive strength. from the above problems regarding the low durability of the asphalt mixture due to flood (even though the asphalt mixture has standards requirement of marshall immersion), and the use of polymer asphalt has high resistance to deformation and crack damage, this study was designed using the ac-wc mixture. as for the purpose of this research is to know the effect of flood water immersion on ac-wc mixture with elastomeric asphalt (ema) asphalt on the compressive strength and mixed elastic modulus with the following objectives: 1. designing a mixture of asphalt concrete wearing course (ac-wc) using elastomeric modified asphalt (ema) on different gradations. 2. finding out the effect of flood water immersion on ac-wc mixture by using elastomeric modified asphalt (ema) on different gradations evaluated from compressive strength and elastic modulus. 3. finding out the durability of the ac-wc mixture by using elastomeric modified asphalt (ema) immersed in flood waters toward compressive strength and elastic modulus of the mixture. 2. methodology the study was conducted in the transportation engineering laboratory of civil and environmental engineering department, faculty of engineering, gadjah mada university, yogyakarta. the conceptual framework of the study is shown in fig. 1. figure 1. research flow chart 2.1. marshall characteristics the marshall test method is the most commonly used and standardized method in the american society for testing and materials 1993 (astm d 1553). the results of marshall testing obtain the result of hot asphalt mixture characteristics, which include [8]: nomenclature: irs index retained strength (%) sn strength on immersion n days ԑ axial strain so strength on immersion 0 days δl change of length of specimen (m) r a the value of the strength drop (%) on the first durability index the value of the strength drop (%) on the second durability index lo σ length of established specimen (m) axial stress si percent of strength remaining at time ti p load axial (kg) s(i+1) percent of strength remaining at time t(i+1) e elastic modulus ti, t(i+1) tn immersion time (starting from the beginning of the test) immersion at n time δσ δԑ the axial voltage difference the axial strain difference edi yusuf adiman and latif budi suparma /al-qadisiyah journal for engineering sciences 15 (2022) 181–186 183 1. density; that is the weight of the mixture measured per unit volume. the density value is influenced by several factors such as high asphalt content and asphalt viscosity. 2. void in the mineral aggregate (vma); that is the space between the aggregate particles on an asphalt pavement, including the air cavity and the effective asphalt volume (excluding aggregate absorbed asphalt volume). 3. void in the mix (vitm). in the asphalt pavement mixture, it comprises the air space between the asphalt aggregate particles. 4. void filled with asphalt (vfwa); that is the percent of the void in the mineral aggregate (vma) filled with asphalt, not including the asphalt absorbed by the aggregate. 5. marshall stability value is obtained based on the value indicated by the dial needle on the marshall stability proving ring attached to the marshall device, then converted into the calibration table according to the proving ring used. 6. marshall flow is shown in the needle indicated by the number in the dial flow, in units of which 1 unit = 0.01 mm (millimeters). consequently, there is no need for the conversion of numbers on flow measurements. 7. marshall quotient (mq) is used to determine the stiffness of asphalt concrete mixture. marshall quotient (mq) is the result of marshall's stability by marshall flow. 2.2. durability testing testing of the durability of the flood water immersion in this study used three methods. 1. index retained strength (irs) 𝐼𝑅𝑆 = 𝑆𝑛 𝑆𝑜 𝑥 100% (1) 2. first durability index (r) first durability index is defined as the number of successive gradients of the durability curve, expressed in equation below. 𝑟 = ∑ 𝑆1−𝑆𝑖+1 𝑡𝑖+1−𝑡1 𝑛−1 𝑖=0 (2) 3. second durability index (a) it is defined as the area of loss of average strength between the durability curve with the line so = 100%, expressed in equation below. 𝑎 = 1 𝑡𝑛 ∑ 𝑎1 = 𝑛 𝑖=0 1 2𝑡𝑛 (𝑆𝑖 − 𝑆𝑖+1 )[2𝑡𝑛 − (𝑡𝑖 + 𝑡𝑖+1)] (3) 2.3. unconfined compression strength unconfined compression strength (ucs) test is used to determine the compressive strength of the material with a cylindrical sample. for compressive strength testing, the ratio l = 2d is generally used, where l is the length and d is the diameter of the sample. there are ways to obtain maximum compressive strength value and elastic modulus value by doing some calculation stages using the following equations: 1. axial strain (ԑ) ԑ = 𝛥𝐿 𝐿𝑜 𝑥 100% (4) 2. axial stress (σ) 𝜎 = 𝑃 𝐴 (5) 3. stress-strain curve, it is made by connecting axial stress (σ) data on the axis and the axial strain (ε) on the ordinate axis. the axial compressive strength is determined based on the maximum axial value where, pmax = σmax. 4. elastic modulus (e) the elastic modulus is the slope in the stress-strain curve located in the elastic linear region. modulus of elasticity is calculated as follows: 𝐸 = 𝛥𝜎 𝛥ԑ (6) 3. analysis and discussions 3.1. ac-wc mixed design determination of aggregate weight on each filter size was adjusted to general specification of bina marga 2010, 3rd revision (2014) with the target of gradation taken from upper limit (ul), middle range (mr) and lower limit (ll). preparation of the specimen used 5 variations of bitumen content of the estimate bitumen content (pb), pb-1%, pb-0,5%, pb, pb + 0,5%, and pb + 1%. from the specimen on the five variations of the bitumen content, marshall test was conducted and the optimum bitumen content (obc) was obtained. the obc values were derived from graphs of marshall characteristic relationships. they were density, vma, vitm, vfwa, marshall stability, marshall flow, and mq, where the graphic relationship showed the asphalt rate range that met the blend specification with the narrow range method. as it used 3 gradation targets (ul, mr, and ll) it would get 3 different obcs according to the target gradation. marshall test results for the determination of obc in each gradation can be seen in fig. 2, fig. 3, and fig. 4. based on the results of obc with the narrow range method shown in fig. 2, fig. 3, and fig. 4, the value of the obc ul gradation was 5.71%, the obc mr gradation was 5.53%, and the obc of ll gradation was 6.97%. 3.2. ac-wc mixed design for ucs specimen designing the weight of the aggregate on the ac-wc mixture for ucs specimen was carried out using a diameter of 3 inches and a height of 6 inches (see fig. 5). the design of material proportions can be seen in table 1. 3.3. test result compressive strength from duration of immersion the test specimen of compressive strength can see from fig. 6, and the results of compressive strength against the duration of immersion in the gradations of ul, mr, and ll can be seen in fig. 7. 184 edi yusuf adiman and latif budi suparma /al-qadisiyah journal for engineering sciences 15 (2022) 181–186 figure 2. obc results of ul gradation figure 3. obc results of mr gradation figure 4. obc results of ll gradation a b figure 5. (a) design ucs mold; (b) sample of ucs specimen. table 1. design of material proportions for ucs specimen no details formula gradation types ul mr ll 1 obc (%) (a) 5.71 5.53 6.97 2 volume (cc) (b) 731.00 731.00 731.00 3 density (gr/cc) (c) 2.35 2.36 2.33 4 w mixture, gram (d) (b) x (c) x 1,03 1768.99 1778.79 1751.12 5 w bitumen, gram (e) [(a)/ 100] x (d) 101.01 98.37 122.05 6 w agaregate, gram (f) (d) (e) 1667.98 1680.42 1629.06 7 w course aggregate, gram (g) [(j)/ 100] x (f) 783.95 957.84 1091.47 8 w fine aggregate, gram (h) [(k)/ 100] x (f) 733.91 613.35 472.43 9 w filler, gram (i) [(l)/ 100] x (f) 150.12 109.23 65.16 aggregate composition: 10 course aggregate (%) (j) 47 57 67 11 fine aggregate (%) (k) 44 36.5 29 12 filler (%) (l) 9 6.5 4 df figure 6. (a) specimen immersion; (b) specimen ucs test; (c) specimen after ucs test min max 5.43 5.99 optimum bitumen content (%) 5.71 7 mq range of bitument content (%) 5 stability 1000 6 flow 2 4 3 vitm 3 5 4 vma 15 1 density 2 vfwa 65 no criteria general spesifications bitumen content (%) 5.0 5.5 6.0 6.5 7.0 min max 5.85 optimum bitumen content (%) 5.53 7 mq range of bitument content (%) 5.2 5 stability 1000 6 flow 2 4 3 vitm 3 5 4 vma 15 1 density 2 vfwa 65 no criteria general spesifications bitumen content (%) 4.5 5.0 5.5 6.0 6.5 min max 6.45 6.97 7.49 optimum bitumen content (%) 7 mq range of bitument content (%) 5 stability 1000 6 flow 2 4 3 vitm 3 5 4 vma 15 1 density 2 vfwa 65 no criteria general spesifications bitumen content (%) 5.5 6.0 6.5 7.0 7.5 edi yusuf adiman and latif budi suparma /al-qadisiyah journal for engineering sciences 15 (2022) 181–186 185 figure 7. the value of compressive strength on the gradations of ul, mr, and ll due to the duration of immersion based on fig. 7, it was shown that all three types of gradations, namely, the gradations of ul, mr, and ll had the same effects as the duration of immersion, the longer the immersion time the compressive strength value would decrease. the value of compressive strength decreasing along with the length of time of this immersion was due to oxidation process in the mixture where the water intrusion into the mixture would weaken the bond between the asphalt and the aggregate causing the compressive strength value of the mixture to decrease. 3.4. durability of compressive strength from duration of immersion 1. index retained strength (irs) the degree of durability of the pavement was obtained from the value of the index retained strength (irs) in which the irs value represented the durability of the asphalt mixture after immersion. the result of calculation of index retained strength (irs) and comparison of irs value due to soaking period can be seen in fig. 8. figure 8. index retained strength (irs) of compresive strength due to duration of immersion on the gradations of ul, mr, and ll due to the duration of immersion fig. 8 shows that the irs value of compressive strength decreased due to the duration of the immersion, and the ul graded mixture, it was the bestdurable mixture of immersion duration at 1, 2, 4, and 7 with the highest compressive irs value between the graded mixture of mr as well as ll graded mixture. 2. first durability index (r) the first durability index was a method of measuring the loss of strength that could describe the durability of hot mix asphalt developed by crauss et al. [9]. the first durability index score was denoted by (r) representing the decreasing value of the compressive strength of a mixture due to immersion. the results of the calculation of first durability index can be seen in fig. 9. figure 9. first durability index (r) based on fig. 9, it could be seen that the ul graded mixture had the lowest compressive strength value (r) compressive strength compared to other graded mixtures of mr and ll graded mixture both at 1, 2, 4, and even 7 days of immersion. this indicated that the ul graded mixture was the most resistant mixture to the duration of submersion when compared to the graded mixture of mr and ll. the compressive strength value is greater in the ul gradation because the ul gradation has a larger composition of fine aggregate and filler than the mr gradation and ll gradation, thus causing the specimens with ul gradation to be easier to compact and also tend to have higher density. 3. second durability index (a) the second durability index was a continuation method after the first durability index which measured the loss of strength through a durability curve that could illustrate the durability of hot mix asphalt. it was also developed by crauss et al. [9] the second durability index showed a strength loss (a) of the mixture. the results of the calculation of the second durability index for the gradations of ul, mr, and ll could be seen in fig. 10. figure 10. second durability index (a) 186 edi yusuf adiman and latif budi suparma /al-qadisiyah journal for engineering sciences 15 (2022) 181–186 similarly with the first durability index, from fig. 10 it could be seen that the ul graded mixture had the lowest loss value of compressive strength of the lowest survival curve (a) compared to the other graded mixtures (the mr and ll graded mixture both at 1 day immersion, 2, 4, even 7 days). this indicated that the ul graded mixture was the most resistant mixture to the duration of immersion when compared with the graded mixture of mr and ll. 3.5. effect of immersion of elastic modulus the elastic modulus value (e) was obtained from the stress-strain relationship curve in the elastic linear region. the test object used in the calculation of the value of elastic modulus was the same test object with the calculation on the specimen on the compression value of compressive strength. the results of elastic modulus testing on the duration of immersion can be seen in fig. 11. figure 11. the elastic modulus value due to the duration of immersion based on fig. 11, it can be seen that the value of elastic modulus (e) resulting from the duration of immersion in the ul graded mixture decreased in soaking days 1 and 2, and again increased in soaking days 4 and 7. for the mr graded mixture, the elasticity modulus (e) value due to the duration of the immersion decreased until the 7th day of immersion, despite the increase in the modulus of elasticity (e) value from the first day immersion to the second day immersion. as for the ll graded mixture, the elastic modulus (e) was fluctuating, which meant that the value of elastic modulus (e) experienced up and down until the 7th day immersion. by looking at the nature of the modulus value of elasticity (e), it could be said that in the three types of gradations, ul, mr, and ll, there was no effect of elasticity modulus (e) on the duration of immersion. 4. conclusions 1. from the design results of the test object, the value of optimum bitumen content on the gradations of the boundary ll, mr and ul was obtained as follows: 6,97%, 5,53% dan 5,71%. 2. the average value of the compressive strength test after immersion for 0, 1, 2, 4, and 7 consecutive days on the gradation of mr was as follows: 70,46 kgf/cm2, 66,66 kgf/cm2, 65,28 kgf/cm2, 63,86 kgf/cm2, 59,53 kgf/cm2, the ul gradation is: 79,01 kgf/cm2, 74,82 kgf/cm2, 74,08 kgf/cm2, 72,49 kgf/cm2, 72,05 kgf/cm2, and ll gradation are : 55,80 kgf/cm2, 52,06 kgf/cm2, 51,49 kgf/cm2, 50,86 kgf/cm2, 48,61 kgf/cm2. from the test results of compressive strength shows that the longer the immersion, the lower the compressive strength in the three types of gradation. 3. the level of mixed durability based on irs value at 1, 2, 4 and 7 days respectively on gradation of mr was as follows: 94,61%; 92,64%; 90,63%; 84,49%, ul gradation is: 94,69%; 93,75%; 91,75%; 91,19%, and ll gradation is: 93,29%; 92,27%; 91,14%; 87.11%. based on the value of the first durability index (r) and the second durability index (a), the gradation of mr had the greatest loss of strength at the time of immersion until the 7th day with a strength loss value (r) of 10,41%, and the loss value strength (a) of 9,02%, and had a residual strength value (sa) of 90,98%. 4. the mean values of elastic modulus testing after immersion for 0, 1, 2, 4, and 7 consecutive days on the mr gradation was as follows: 12635 kgf/cm2, 8866 kgf/cm2, 9138 kgf/cm2, 7764 kgf/cm2, 7637 kgf/cm2, ul gradation is: 8886 kgf/cm2, 8851 kgf/cm2, 6827 kgf/cm2, 7709 kgf/cm2, 9779 kgf/cm2, and ll gradaation are : 6475 kgf/cm2, 8316 kgf/cm2, 5861 kgf/cm2, 7070 kgf/cm2, 6051 kgf/cm2. the results of examination of elastic modulus value that was fluctuating to the duration of immersion indicated no significant influence between the value of elastic modulus with the duration of immersion. references [1] hardiyatmo, h. (2015), road pavement design and soil investigation, ugm press, yogyakarta. [2] department of settlement and regional infrastructure, 2002, flexible pavement thickness planning, building construction guidelines, pt t-01-2002-b. [3] ministry of public works, directorate general of highways, 2020, general specification of road pavement 2018 (2nd revision), jakarta. [4] wibawa, i. m. p., 2016, effect of continuous and periodic immersion of flood water on the durability of asphalt concrete wearing course mix with elastomeric modified asphalt binder (ema), thesis, gadjah mada university. [5] farret, p., 2016, the effect of continuous and periodic immersion of water on the durability of asphalt concrete wearing course (ac-wc) mixture with elastomeric modified asphalt binder, thesis, gadjah mada university. [6] hadi, s. (2016), material technology, publisher andi, yogyakarta. [7] s. starodusbsky, i blechman, and m. livneh. “stress-strain relationship for asphalt concrete in compression”, material and structures, vol. 27, pp. 474-482, 1994. [8] asphalt institute, 1993, for asphalt concrete and other hot-mix types, manual series no. 2 (ms-2), sixth edition, lexington, usa. [9] pangaraya, d., 2014, laboratory study on the use of asphalt starbit e -55 modified polymer in asphalt concrete-wearing course (ac-wc) in terms of durability and indirect tensile strength, thesis, gadjah mada university. references [1] hardiyatmo, h. (2015), road pavement design and soil investigation, ugm press, yogyakarta. [2] department of settlement and regional infrastructure, 2002, flexible pavement thickness planning, building construction guidelines, pt t-01-2002-b. [3] ministry of public works, directorate general of highways, 2020, general specification of road pavement 2018 (2nd revision), jakarta. [4] wibawa, i. m. p., 2016, effect of continuous and periodic immersion of flood water on the durability of asphalt concrete wearing course mix with elastomeric modified asphalt binder (ema), thesis, gadjah mada university. [5] farret, p., 2016, the effect of continuous and periodic immersion of water on the durability of asphalt concrete wearing course (ac-wc) mixture with elastomeric modified asphalt binder, thesis, gadjah mada university. [6] hadi, s. (2016), material technology, publisher andi, yogyakarta. [7] s. starodusbsky, i blechman, and m. livneh. “stress-strain relationship for asphalt concrete in compression”, material and structures, vol. 27, pp. 474-482, 1994. [8] asphalt institute, 1993, for asphalt concrete and other hot-mix types, manual series no. 2 (ms-2), sixth edition, lexington, usa. [9] pangaraya, d., 2014, laboratory study on the use of asphalt starbit e-55 modified polymer in asphalt concrete-wearing course (ac-wc) in terms of durability and indirect tensile strength, thesis, gadjah mada university. article al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohamed.aldawody@qu.edu.iq (mohamed al-dawody) https://doi.org/10.30772/qjes.v14i1.751 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. use of lpg in si enginea review study ghufran talib hashem a, mohamed al-dawody a* a department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq. a r t i c l e i n f o article history: received 22 march 2021 received in revised form 18 may 2021 accepted 23 may 2021 keywords: lpg si engine dual fuel performance exhaust emission. a b s t r a c t the depletion rate of conventional petroleum fuels is very fast. gasoline is used as conventional fuel in the si engine. emissions from this fuel cause environmental pollution because it produces harmful emissions for the environment such as co2, co, hc, and nox. liquefied petroleum gas (lpg) has physical and chemical properties that make it a favorable fuel for ic engines. it can be used as a fuel alone or combined with gasoline with some minor engine modifications. the engine running on lpg showed improved performance in terms of fuel economy, overall efficiency compared to petrol. in addition, it is noted that lpg emissions are greatly lower than petrol. this work reviews the research conducted by previous researchers on lpg-powered si engines under several working conditions. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction consumption of petroleum products has risen dramatically in the last decade due to the rise in car use and the rapid pace of technological and industrial growth worldwide. gasoline is traditional fuel used in spark ignition engines chung et al. [1]. petrol is derived from crude oil, and its cost is increasing due to limited crude oil reserves. furthermore, the limited reserves of fossil fuels would not be adequate to satisfy energy requirements in the close future, and the difficult of fuel paucity will become very serious [2-3]. in addition, one of the most important interest around the world is the ecological issue due to vehicle emissions. ecofriendly pollution and modification of energy sources arise from the necessity for substitute fuels for automobile uses mistry et al. [4]. alternative fuels are classified into industrial gasoline, alcohols, gaseous fuels and others[5-6]. alternative fuels are promising in the future in the transportation sector, as shown in fig. 1. it is expected that the use of conventional fuels in transportation will decrease by about 24% by 2050 compared to 2005, and the trend towards the use of alternative fuels, mainly due to reducing emissions, and also to improve the efficiency of the transportation system fuels and reports [9]. gaseous fuels such as lpg have been used extensively around the world in sie because it has less impact on global warming emissions than any other fossil fuel in addition to its distinct properties such as higher octane number, lesser polluting exhaust emission, greater calorific value and economic expenses. several researchers have conducted a large number of educations on lpg as a fuel in the sie and it has been described that the use of lpg has a important impact on emissions regulator and performance [7-8]. http://qu.edu.iq/ mailto:mohamed.aldawody@qu.edu.iq https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 55 ghufran talib hashem and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 figure 1. total energy consumption in the transport sector [45] 2. introduction to lpg liquefied petroleum gas (lpg), 55% of lpg is obtained from natural gas refining and the remaining 45% extraction from refining crude oil taha et al. [10]. lpg is a gas consisting mainly of propane and butane, except that it could likewise contain various hydrocarbons such as propane, and n-butane in different amounts as presented in table 1. it is only compressed 5 -20 bar and it works perfectly as an alternative fuel in si engines zhang [11] .it is odorless and for safety reasons, odorless has been added to detect undetected leaks that could lead to hazardous situations, because lpg is heavier than air. one of the most important alternative fuels in si engine is lpg because of several reasons, including the high octane number (110+) which enables the compression ratio (cr) to be as great as 15: 1, which is in the variety of 8: 1 to 9.5: 1 for petrol engines[10], the large global reserve of these gases, high heating value, and low emissions from burning in engines, in addition to their lower prices compared to gasoline chaichan et al.[12]. lpg has a greater ignition temp. than petrol, which delays self-ignition of fuel and thus avoids knocking bisen et al. [13]. table 1: composition of iraqi lpg no. components % vol. 1 methane 2 ethane 0.03 3 propane 20.13 4 iso-butane 19.35 5 n-butane 59.97 6 total c4 79.32 7 iso-pentane 0.50 8 n-pentene 0.02 9 pentane and heavier 0.52 3. lpg in internal combustion engine vehicles running on liquefied petroleum gas (lpg) have been rapidly developed, as they are more economical and less polluting [14, 15]. expected benefits of using lpg in si are inexpensive and environmentally friendly. the sie can be easily reformed to work on lpg [9]. note in double fuel gas engines, gaseous fuel is introduced with air, and this mix of air and gas is compacted as is the state in conventional engines saraf et al. [16]. the lpg device runs under high pressure ratio. thus, it has better thermal efficiency than a petrol engine due to its high octane rating elnajjar et al. [17]. this means that it is possible to increase engine power output and fuel efficiency to what is possible with a petrol engine without producing a damaging phenomenon knocking . also, given that lpg arrives the engine's combustion chambers as vapour, it does not remove the oil from cylinder sides or weak oil while the engine is cold. this helps to get a longer lifetime as well as reduce engine maintenance costs. lpg is less hazardous than any other petroleum-based fuel and is expected to produce fewer emissions of carbon dioxide, nitrogen oxides, and may cause less ozone formation than gasoline engines pundkar et al. [18] . several scientists have studied with lpg as an substitute fuel for si engines. a amount of proposals have been put forward by them to improves performance with this new fuel. a comparison of the physical properties and combustion characteristics of iraqi lpg and traditional fuels(iraqi gasoline) is shown in table 2. table 2: fuel properties at 25°c and 1 atm [19-20] property gasoline lpg density, kg/m3 730 1.85/505 flammability limits (ø) 0.7-4 0.7-1.7 auto ignition temperature in air, (k) 550 588 lower heating value (mj/kg) 44.79 46.22 stoichiometric fuel/air mass ratio 0.068 0.064 flame velocity (m/s) 0.37-0.43 0.48 adiabatic flame temperature (k) 2580 2263 4. literature review in the recent period, the price of liquid fuel extracted from crude oil as well as the increasing concerns about environmental pollution emitted by cars have led to an increase in interest in alternative engine fuels [16]. several researchers have studied the usage of lpg as an alternative fuel in the sie. experts and researchers conducted many experimental and theoretical investigations on the sie supplied with lpg under dissimilar working conditions and standards and favourable results were obtained in terms of thermal efficiency, fuel cheap, as well as exhaust emissions. lpg combustion properties are higher to petrol in lean engines jothi et al. [21]. because of its effective combustion properties, lpg is commonly used in sie but vehicles running on lpg fuels, in which fuel systems have been overridden from those of petrol engines, cannot realize a higher compression ratio and thus greater thermal efficiency where no converted engines can take advantage of the high octane number of lpg [16]. lpg gas as a low carbon and high octane number fuel produces lower carbon dioxide (co2) emission as compared to gasoline[22-23]. ehsan m.d. et al. [24] described working on 200 cc 1cylinder, 4 stroke, si coupled to generator with output power of 1.5 kw, 220v, 50hz of electricity. the engine set's air inlet has been changed to use lpg. the load was applied to the motor as an electrical load. the test exhibited under the similar loading conditions, the fuel consumption of petrol was higher than that of lpg. in the absence of a load the flow of gasoline was 0.52 kg / hr and at a full load around 1kg / hr. whereas in the situation of lpg from (0 to 400) watts the fuel consumed was 0.55 and 0.62 kg per hour respectively.the consumption of lpg fuel was 0.78 kg / hour ,at the maximum load of 1.3 kw. choi et al.[25] estimated of combustion and emission characteristics of the lpg fed by sie was presented with some simple modifications in standard sie on lpg fuel with variable proportions of lpg ( 5%, 10%, 56 ghufran talib hashem and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 20%) with assistance of the plc control. engine velocity is fixed at 4000 rpm, and the relative (air-to-fuel) ratio ranges ( 0.8 to 1.3). the five gases analyzer was used to measure the exhaust gas components (co2, co, hc, and nox). it was also observed that the maximum co2 emission at about λ=1 and displays smaller fractions at rich and lean mixtures. increase percentage of lpg in petrol increases the speed of combustion of the mixture significantly and thus reduces the combustion period and thus increases the maximum temperature inside the cylinder. at a high fuel-toair ratio, the amount of measured nitrogen oxides was much higher, and uhc showed a noticeable decrease as the relative fuel air ratio exceeded stoichiometric. lee hyung ki et al. [26] investigated the combustion properties as well as the flame spread of lpg and petrol through a laser diffraction process and high-speed photographic technique in a fixed-size combustion chamber. the researcher showed that as the initial temperature increased and the primary pressure decreased, the flame spread velocity increased. the equivalence ratio was quite specifically influenced by the flame velocity, combustion pressure and therefore the time of combustion of the fuel-air mixture. in addition, the comparison of the flame spread between lpg and petrol showed that for the lean mixture, the flame spread of lpg was faster than gasoline, whereas for the rich mixture, the flame speed of petrol was faster than that of lpg. mistry c. s. and gandhi a. h [4] modified the unoriginal multicylinder water-cooled, vertical, si engine to operate on lpg and gasoline as dual fuel. morse test was performed for modified motor under changing loading conditions with changing speed. from the results of the morse test, it was noticed that the frictional force in case of using gasoline was less compared to lpg. it had been noticed that in the case of gasoline the thermal efficiency of the brake and the indicated thermal efficiency is higher than that of lpg. moreover, and the flame speed of lpg is less than that of gasoline, thus spark timing should be developed to get the best results ignition condition for lpg. hakan b. and orhan d.[7] developed a computer program to make numerical calculations for the semi_dimensional sie to guess performance, cycle and exhaust emission of automobile engines in case of the use of lpg as a replacement fuel under changed engine speed and equivalence ratio of fuel and air, and the equations governing the study of the mathematical model consisted mainly of ordinary differential equations derived for temperature and cylinder pressure. the results of simulation comparison showed that si engines using lpg fuel showed a significant improvement in the exhaust emission characteristics. s. murillo et al. [27] conducted an experimental study to determine the performance and measurement of the emission index of the si engine liquefied petroleum gas. the results showed that with the use of lpg, the specific fuel consumption decreases co and co2 emissions were much lower. without noticeable loss of energy but noticeable nox emissions it was high. radu b. et al.[28] investigative some knockdown characteristics by focusing on the development of a simple arrhenius type correlation to the delay time of the strike was performed on a sie for heavyweight vehicles using commercial lpg based on experimental data for the crank angle of the strike, pressure and simulation temperatures of un-burned gases. temperatures were computed in addition to subtracting some of the autoignition characteristics of lpg in the engine, taking into account the heat release rates due to auto-ignition, and they were compared with former results of unmixed propane. results showed a qualitative correlation between the rate of heat release through the intensity of the blow and the self-ignition reactions. ristovski z.d. et al.[29] studied carbon dioxide emissions and particulate matter at changed vehicle velocities (0 (passive), 40, 60, 80 and 100) km / hour . the study was conducted on five ford falcon forte (ulp) passenger cars and six custom passenger cars running on liquefied petroleum gas. the results showed that in all operating methods, the particle number emission factor using lpg was lower compared to ulp. cmd in lpg condition was greater than unleaded petrol in all types excepting in no-lood mode, where numerical analysis at 60 and 80 km / hr showed significant differences. in addition, the co2 emission factors for ulp were greater than that of lpg, and at 100 km / h a statistically significant difference was observed. ceviz m.a. and yuksel f. [30] compared cyclical difference and emissions of lpg with petrol fuel fired under poor operating conditions. the testing was carried out on four (air,fuel) gasoline mixes and five mixtures values for lpg. it was observed that a rise in the relative ratio between air and fuel leads to an increase in the coefficient of variation in the composition. however, the higher flame speed of lpg combined with the good mixing of the gaseous fuel with the air leads to a decrease in the periodic variations, and the higher h / c ratio of lpg reduces engine emissions and thus lpg is a more convenience fuel in a light internal combustion engine comparable with petrol. arslan o. et al. [31] attempted an experimental investigation on a si four-cylinder engine modified to operate with liquefied petroleum gas (lpg) to study engine characteristics under cold weather conditions. it is found that bsfc of lpg is higher than that of gasoline. while the carbon dioxide concentration was decreasing with increasing engine speed in both fuels, the decrease was higher for lpg, and the hydrocarbon emissions were great at 1000 rpm, and with the increase in speed the hc concentration decreased, in comparison with petrol, hc concentration for lpg was found to be poor at all speeds. lower hydrocarbons emission of lpg is reported for all ranges of engine speed compared to gasoline. it has been found that co emissions on unloading and loading are reduced at different engine speeds. gumus m.[32] had been investigatived the effect of difference in volumetric efficiency on the emission characteristics of the si engine with the use of lpg in different proportions (25%, 50%, 75%, 100%), experiments conducted at constant speed of 3800 rpm and with different load (5, 30, 60 and 90) percent. differences in brake thermal efficiency, air-to-fuel ratio, bsfc, and exhaust gases were examined. significantly when using lpg, the volumetric efficiency is decreased. the air to fuel ratio decreases as the level of lpg usage increases. bsfc and bsec are reduced while preserving thermal efficiency. in terms of exhaust emissions, positive results were obtained at all levels of lpg consumption. when using 100 percent lpg for exhaust emissions, the best results are obtained. salhab z. et. al. [33] studied of 4-stroke si outboard engine powered by lpg. it is modified to run on alternative fuel and on gasoline. two different operating methods have been developed with lpg; the first is by using the vacuum produced by the engine, which provides a stable mixture to the engine's carburetion, while the second method was implemented using fuel injection (lpg). the results showed that low engine brake power, specific brake fuel consumption. the results show that with the use of injected lpg; the brake power, engine torque and specific fuel consumption of the brakes were lower compared to gasoline, while the vacuum system was higher excluding brake force. the emissions of co, co2 and nox were lowered in the lpg mode compared to the petrol mode while the hc emissions were high. shankar k. s, mohanan p [34] studied the performance of fourcylinder petrol engine. the engine was modified to operate with lpg 57 ghufran talib hashem and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 injection. the experimental study is conducted on variable motor speed adjustment at 5 ° btdc then advance and delay timing to 6° btdc, 4° and 3° btdc respectively. the results showed lower thermal efficiency indicated at low engine speed and 5 degrees btdc for lpg but beyond 3,500 rpm higher efficiency for lpg detected compared to gasoline. reduced co2 and hc emissions with lpg. while there was an increase in nitrogen oxide emissions of lpg at 4,500 rpm. when the ignition timing is brought up to 6 ° btdc, the efficiency is high at low engine speed and when delayed to 4 ° and 3 ° btdc results in an increased specified power consumption. emissions of 6 ° btdc, hc and co are found to be lower for lpg. delayed time of ignition caused incomplete combustion and consequently high co emission at 6 ° btdc and lower at 3 ° and 4 ° btdc. hwang i g. et al. [35] compared the combustion phenomena as well as the emission characteristics of nanoparticles from the spark ignition engine by direct wall-directed injection (di) of liquefied petroleum gas (lpg) and benzene. the gasoline direct injection (gdi) fuel supply system has been modified for the liquid-type lpg injection fuel supply system. to confirm the clean combustion properties of the lpg di engine, emissions and concentrations of nanoparticles for an lpgpowered engine were compared with those of the petrol engine. the results showed that the emissions of nanoparticles and exhaust of the lpg di engine were significantly lower than those of the gdi engine. combustion performance at full lpg loading was similar to that of gasoline fuel. masi massimo [36] took into their considerations the following factors: brake performance comparison for a si 4-stroke , five-cylinder engine feeding with lpg in addition to petrol. the engine is converted by the standard third-generation kit to dual fuel operation. the kit is an injection system. the fuel is electronically multi-port and serial delivers lpg in the gaseous state to the upstream intake holes of the gasoline injector. the results showed that the engine brake force was more in the petrol mode for the same test conditions. in addition, the operating performance of lpg decreased due to lack of lpg feeding in the combustor. erkus b. et al.[37] reported the impact of multi-phase lpg injection system on the performance of si engine was investigated. experiments were conducted at engine speeds of 2000-4000 rpm. a stable throttle position of (25-50) percent of the fully open position were performed experiments. to compare the performance of mixing systems and different fuels, lpg with gasoline and carbon lpg. the results showed a higher brake force achieved for lpg injection system compared to gasoline and lpg carbonate. the volumetric efficiency also presented an perfection in the lpg injection system compared to the carbonization systems at each throttle position. both modes of throttle have lower bsfc with the lpg injection system except 2500 rpm it raised by 25percent. sulaiman m.y. et al. [38] analyzed engine speed and torque under wot (wide open throttle) of an si lpg powered si engine with a global dynamometer. tests were conducted with an air-cooled four-stroke sparkignition engine. the test was conducted in three modes. the first mode is ulp fuel system, the second is lpg evaporator (lpg v) and the third is the lpg capsule valve (lpg b). the results showed that the sfc and the energy produced from mode ii lpg v and mode iii lpg b are lower than that of ulp. çinar c. et al. [39] performed a comparative study of the performance and emissions of the si engine powered by lpg and unleaded gasoline. the engine was modified to run on lpg. the results showed a decrease in engine torque and power and an increase in bsfc when the engine was running converted to lpg fuel and a 7mm valve lift. additionally, improvements to co and hc emissions were observed with lpg fuels while emissions of nitrogen oxides rise. also, improvements are on engine performance results depending on the increased quantity of mixture taken in a cylinder with lpg . chaichan m. t. et al.[12] conducted a practical study using 2-types of gaseous fuel (ng, lpg) with single cylinder si-engine with compression ratio variable, velocity and spark timing. ricardo e6 / usa then comparing its performance with gasoline engine. results it appears that a greater useful compression ratio for gasoline, lpg and natural gas are (8/1), (10.5/1) and (13/1) respectively. the findings showed that when using ng, spark timing was more advanced than other fuels, due to decreased flame spread in the combustion chamber. the findings showed that the consumption of fuel was determined on a mass basis for lpg, which was lower than gasoline and higher than natural gas. it was also found that the temperature of the exhaust gas of lpg is lower than gasoline and more expensive than natural gas. bielaczyc piotr et al. [40] tested two si vehicles. the vehicles were adapted by the manufacturers of binary fuels gasoline and gaseous fuels. the first vehicle works with (liquefied petroleum gas and gasoline) and the other works with (compressed natural gas and benzene). the emissions of thc, nox , co and co2 were analyzed. using special additional equipment installed on the existing gasoline refueling system. cars in this test feature multi-point gas injection systems. the objective of the work is an analysis of the effect of gaseous fuels on exhaust emissions on the emissions comparison of gasoline-powered vehicles. the researcher noticed that emissions of carbon dioxide and thc increased in cng fuel vehicles while emissions of nitrogen oxides were lower compared to gasoline. in vehicles running on lpg fuel, co emissions were much lower than gasoline and thc emissions were similar to gasoline but nitrogen oxides emissions were higher compared to gasoline, however, co2 emissions were reduced for both lpg and compressed natural gas vehicles. suyabodha a.[41] considered the use of lpg and gasoline 95 as substitute fuel in petrol engines in continuous and fast driving conditions. the results of the study showed that the best fuel consumption at an average speed of 100 km / h. the difference in energy consumption is due to lpg properties which is compared to gasoline 95 has a higher flame intensity. the injection of lpg resulted in a successful preparation of the mixture. hence, the pressure in the combustion chamber increased, resulting in greater output power than the 95th gasoline under partial load conditions. tukiman m. m. et al.[42] studied and investigated of the performance and emissions of the petrol engine when lpg substitutes gasoline in addition to determining the effect of the lpg system in the liquid state. the engine was modified by adding a multi-port injection system (mpi) to deliver fuel to the engine in addition to installing a near-intake valve with a sequential injection system liquid lpg (lsi) without affecting the gasoline injector. the performance result showed with lpg increased efficiency, power and decreased bsfc. the exhaust emission of co, hc and nox increased compared to gasoline. mustaffa n. et al.[43] studied the combustion, performance and emissions characteristics of a four-stroke spark ignition engine using lpg as an alternative fuel and compare the results with unleaded gasoline (ulp). the experiments were conducted at a constant speed of 3000 r.p.m at various load conditions. the results of the combustion analysis showed that lpg had a higher pressure inside the cylinder and a higher pressure rate compared to ulp. the heat release rate (rohr) of lpg had increased before ulp. the results showed that brake effective pressure (bmep) and torque were higher for lpg compared to ulp. and that 58 ghufran talib hashem and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 brake specific fuel consumption (bsfc) for lpg injection is lower as compared to ulp. meanwhile, emissions of carbon monoxide (co), nitrogen oxides (nox) and hydrocarbon (hc) for lpg recorded higher. usman muhammad and hayat nasir [44] studied the performance and emissions in addition to the deterioration of lubricant oil for 125 cc motorcycle engines running on liquefied petroleum gas and gasoline. the result showed a deterioration of the lubricant oil when operating the motorcycle for both types of fuels. also, the brake force, torque and maximum speed of the lpg-powered motorcycle were lower compared with gasoline and lower emissions from lpg compared to gasoline. mohammed h.a. and abdulhaleem s.m.[46] studied the effect of adding lpg fuel in different proportions with naphtha or gasoline on engine performance and pollutant emissions. experiments were conducted on the spark ignition engine under different load conditions, constant cr (6: 1) and different mixing ratios (10-25)%. the results showed that mixing lpg improves the thermal efficiency of the brakes and the specific fuel consumption of the brakes and reduces carbon monoxide, carbon dioxide and nitrogen oxides, but it increases the concentration of hydrocarbons. table 3: summary of researchers contributions of lpg mustafa k. f. and gitano-briggs h.w.[47] performed an experimental study to measure exhaust emissions from a four-stroke spark ignition engine modified to run with both lpg and gasoline. experiments were done at different mixing ratios (5%, 10% and 20%) at a constant speed of 4000 rpm. it has been found that by increasing the proportion of lpg in gasoline, the level of carbon dioxide (co2) reaches a peak at a relative air fuel ratio of 1.0, and that carbon monoxide (co) shows a sharp decrease with the increase in the relative proportion of air fuel. the unburned hydrocarbons (uhc) also show a marked decrease as the relative air-fuel ratio exceeds the stoichiometric measures and nitrogen oxides (nox) show an increasing trend as the air-to-fuel relative ratio increases. researcher name experimental fuels results summary [23] dr. md. ehsan2001 gasoline and lpg which consists of propane 85% min. propylene 5% max. butane and heavier hc 2.5% max sulphur 120 ppm max better mixing and combustion, lower fuel consumption and improved emission characteristics. the power output decreased. more economical than gasoline [24] g. choi 2002 lpg was approximately mixture of 95% butane and 5% propane using fuel lpg 100% propane the power output of lpg system with liquid-phase is approximately 17% higher than that of vapor -phase mixer. cr is increased, power output is decreased & maximum cylinder pressure decreased [25] k.h. lee 2002 lpg and gasoline the maximum flame propagation speed appeared at the stoichiometric equivalence ratio condition (ø=1.0) for lpg, but at equivalence ratio of 1.1 for gasoline, the flame speed of lpg is faster than that of gasoline at the range of lean or stoichiometric equivalence ratios. however at the range of rich equivalence ratio conditions, the speed of flame propagation for the gasoline was superior to that of lpg. [4] c.s. mistry 2004 dual fuel mode lpg and petrol brake thermal and indicated thermal efficiencies were higher for petrol .fuel consumption was higher in the case of lpg. friction power was higher in the case of lpg. [7] hakan b. 2005 1lpg is considered to consist of only propane. decrements of about 3–4% in engine power output and volumetric efficiency computed for the lpg fueled engine are lower than those for gasoline. lpg increases the specific fuel consumption of the engine. [26] s. murillo 2005 gasoline and lpg reduction in power outboard engine, fuel consumption and pollutant emission [27] radu b 2005 commercial lpg, (8387 ) % propane, (9-15) % alkenes, it was proved that reactions leading to auto ignition in the case of lpg proceed via chemical kinetics with cool flames. a qualitative correlation between the rate of heat release by auto ignition reactions and knock intensity is apparent. [28] z. ristovski 2005 2ulp and lpg lpg was found to be the cleaner fuel with respect to both particle and carbon dioxide emissions 59 ghufran talib hashem and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 [29] m. ceviz 2006 gasoline and lpg 3relative air–fuel ratio increases. co emissions decreases, and there is no serious change over the lean burn operating condition. co2 emission decreased with lower c number of fuel (lpg) and leaner mixture [30] o. arslan 2010 leaded gasoline c8h18 lpg (30% c3h8 +,70% c4h10) without mixer co &co2 emission has been reduced with mixer the specific fuel consumption increases. as a result of this increasing, the emissions t are relatively higher in comparison of the gasoline usage [31] m. gumus 2011 gasoline and lpg fuel is composed of (50% c3h8 and 50% c4h10) the volumetric effi. was shown a decrease depending on the lpg usage. a/f decreases with the increase in lpg usage level and the minimum a/f value was obtained at 100% lpg usage. with the use of mixture containing 25% lpg, bsfc and bsec decreased while the bte was maintained. best results in terms of exhaust emissions were achieved at using 100% lpg. [32] z. salhab 2011 gasoline and lpg it was concluded that using lpg instead of conventional gasoline results in reduced engine brake power, pollutant emissions and specific brake fuel consumption, with energy loss (7%). [33] k. shankar 2011 4gasoline and lpg the advanced ignition timing when using lpg has resulted in reduced emissions of co and hc. but it shows an increase in nox emissions. and gives better thermal efficiency [34] i. hwang 2012 gasoline and lpg of ( nbutane 46.4 % i-butane 29.9 % and propane 23% ) the particle emission levels of the lpg di engine were lower than those of the gdi engine by one order of magnitude. the engine-out hc emission levels decreased, but the nox concentration increased [35] m. masi 2012 gasoline and dual-fuel operation petrol and lpg performance deterioration in lpg operation due to deterioration in volumetric efficiency and insufficient fuel delivery. [36] b. erkuş 2013 gasoline and lpg engine has higher power outputs. less fuel consumption. lower exhaust emissions. [37] m. sulaiman 2013 unleaded petrol and lpg ( 40 % propane and 60 % butane) slight power output reduction, due to the lower volumetric efficiencies and unaltered ignition timing of the engine. lpg consume less fuel. lpg has better energy price as compared to the conventional fuel, which is ulp [38] c.çinar 2016 dual fuel (gasoline and lpg) torque and power decreased and bsfc increased when the engine was converted to lpg. hc and co emissions decrease were observed with lpg fuel while nox emissions increased. improvements on the engine performance results [40] p. bielaczyc 2016 gasoline , lpg and cng in cng fuelled vehicle co and hc emissions were increased in while nox emissions lower in comparison to petrol. in case of lpg fuelled vehicles hc emissions were similar to petrol and co lower but nox higher, however, the co2 emissions were decreased for both lpg and cng operated vehicle [41] a. suyabodha 2017 gasoline 95 stoichiometric ratio 14.7 :1, phase of injection liquid o.n 80-95 lpg stoichiometric ratio 15.6:1, phase of injection vapour, o.n 106-111 the energy consumption rate of lpg was less than using gasoline95 under constant speed test although the vehicle consumed lpg slightly higher than gasoline95. the engine power was generated more than lpg under full throttle position. [42] m.m. tukiman 2018 lpg (60% c4h10 + 40%c3h8) the lpg liquid phase was improved bt and bp compared with gasoline fuel. variation of exhaust emission from co has significantly reduced & emission exhaust hc emitted from lpg is higher than gasoline as the engine speed increased. the concentrations of nox emission for lpg are higher compared to gasoline. bsfc improvement when using lpg at low speed engine [43] n. mustaffa 2019 petrol and lpg engine torque and bmep as compared with ulp and bsfc significantly improved. average nox, hc and co emissions were higher for liquid lpg as compared with the ulp. [44] m. usman 2020 petrol and lpg (propane 95 , % butane 5%) reduced maximum speed, torque and power. lpg produced lower hc ,co ,co2 and nox emissions comparison to petrol, lower. flash point and ash contents decreased for petrol whereas the same for lpg. 60 ghufran talib hashem and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences 14 (2021) 054–0 16 5. summary/ conclusions this paper offers a review of the researchers’ works conducted on the use of petrol engines powered by lpg. it has been found that the most effective way to eliminate the problem of fossil fuel scarcity and exhaust emissions is the dual fuel process. the performance, combustion and emission characteristics of engines running on lpg fuel as an alternative fuel to gasoline reviewed extensively. studies have indicated that performance, combustion and emission properties can be improved by improving compression ratio, ignition timing, engine speed, loading status, test fuel supply, injection timing, and inlet manifold condition. based on current study the next conclusions are summarized below: 1. the use of lpg in the si system can be exchanged instantly from lpg to petrol fuel and no much cost is required. 2. feeding si engine with lpg improved combustion characteristics, reduced emissions and fuel consumption. 3. since the entry of lpg into the combustion chamber in the gaseous state, this causes air and lpg to form a homogeneous mixture of fats. it significantly reduces nox emissions. 4. fuel consumption for braking is lower for lpg-using engine compared to conventional fuel under same loading conditions. 5. lpg has a high calorific value, which leads to the increase of the fuel burning rate and the shortening of the combustion time, thus the fuel consumption specified for the brakes is reduced. 6. lpg can be used with higher compression ratios and lower thumping level, thus enhancing engine efficiency. 7. lpg engines have higher cylinder temperature and pressure compared to conventional fuels. references [1] s. chung, j. yeom, j. yoon, s.j.j.o.m.s. hwang, technology, an experimental study on spray and combustion characteristics of lpg for application in direct-injection, 30(5) (2016) 2343-2351. 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[47]k. mustafa, h. gitano-briggs, effect of variation in liquefied petroleum gas (lpg) proportions in spark ignition engine emissions, international conference on environment, 2008. article al-qadisiyah journal for engineering sciences 15 (2022) 148–156 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mortadhahamid@gmail.com (murtadha hamid khashan) https://doi.org/10.30772/qjes.v15i3.827 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. comparative study for pb2+ adsorption from simulated wastewater of battery manufacture on activated carbon prepared from rice husk with different activation agents murtadha hamid khashan* and abbas khalaf mohammad department of chemical engineering, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 25 june 2022 received in revised form 03 august 2022 accepted 20 september 2022 keywords: rice husks fesem bet lead ion chemical activation adsorption heavy metals a b s t r a c t this study contains a lab-scale investigation into the feasibility of applying an adsorption technique to treat wastewater polluted with lead metal simulated to that exhaust from a battery manufactory. rice husks have been prepared for use in three forms; natural rice husks without any activation, activated carbon of rice husks pretreated with sulfuric acid h2so4, and the other pretreated with potassium hydroxide koh. activated carbon using koh provided the best condition for the removal of lead than carbon activated using h2so4 and natural rice husks. the bet surface area and surface morphology by fesem analysis were characterized. the values of surface area were (20, 561, 722) m2/g for natural rice husk, activated carbon pretreated with sulfuric acid, and potassium hydroxide respectively. the adsorption process was studied using pb2+ at temperatures of (25-40)o c and for a concentration range of (20-100) mg/l. the maximum removal ratios of lead pb2+ for natural rice husks and sulfuric acid or hydroxide potassium activation after 1h were 51.21%, 92.3%, and 97.25%, respectively. the maximum adsorption capacity of lead pb2+ onto natural rice husks, rice husks pretreated with h2so4 or koh, and into activated carbons was (37, 86.2 and 94.6) mg/g respectively, at a concentration of 100 ppm and at 25oc. the equilibrium adsorption curves were obtained for pb2+ and the data was fairly well fitted with freundlich-isotherm with a confidence level of 0.99. the kinetic of adsorption was studied by using two kinetic models, pseudo first order and pseudo second order. the results showed the rapid increase in the rate of adsorption at the initial until equilibrium achieved. pseudo second order model was represented the data very well with confidence level 0.99. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction every year, large amounts of wastewater containing heavy metals like lead (pb2+) are discharged into the environment [1]. pb2+ has negative health and environmental consequences. when wastewater containing pb2+ is discharged directly into surface water, seawater, or groundwater, it has a significant impact on the lives of organisms [2]. heavy metals like lead, iron, zinc, nickel, mercury, silver, iron, chromium, gold, arsenic, cobalt, molybdenum, aluminum, and manganese can be accumulate and absorbed in the human body, causing serious health issues [3]. pb2+ has been linked to cancer, organ damage harm, and nervous system damage, among other health issues. minerals such as lead, zinc, and iron are http://qu.edu.iq/ mailto::%20mortadhahamid@gmail.com https://doi.org/10.30772/qjes.v15i3.827 https://doi.org/10.30772/qjes.v15i3.827 http://creativecommons.org/licenses/by/4.0/ murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 149 regarded to be particularly poisonous. lead (pb2+) has been identified as a major source of damage to the nervous and immunological system [4]. therefore, these pollutants must be reduced to an acceptable level before disposal to the environment and according to the limits permitted by the international regulations and laws of the world health organization (who) [5]. there are many industries responsible for the disposal of organic or non-organic pollutants through the discharge of wastewater directly into the environment, such as battery manufacturing, pulp, food, paper, mining, fertilizer, pharmaceutical, and petrochemical, in addition to the refineries which considered as most used industry locally [6]. this study focuses on lead pb2+ heavy metal that discharge from battery manufacturing which causes harmful effects on the environment and people's health. there are many methods used for this purpose, including chemical precipitation, membrane filtration, ion exchange, and electrochemical treatment methods, in addition to adsorption (bratby 2016). however, these methods have some limitations, and disadvantages such as low efficiency, high power consumption, and high quantity of sludge production[7]. bio adsorbents have emerged as one of the promising heavy metal and metalloid removal solutions. fungi, plants, and algae are examples of biomass-derived adsorbents capable of adsorbing heavy metals from the solutions[8]. due to functional groups such as imidazole, carboxyl, hydroxyl, amino, phosphate, sulfate, phenol, carbonyl, and amide, bio-adsorbents have an affinity for heavy metal ions to form metal complexes or chelates [9]. rh is a low-cost (agricultural by-product) bio adsorbent that has been extensively explored for the removal of numerous heavy metals from both groundwater and surface water, including pb, cd, zn, ni, and as [10]. the success of these techniques depends on the development of an efficient adsorbent. according to literature, these adsorbents may be natural, industrial, agricultural, domestic waste, or by-products [11]. decontamination of lead pb2+ heavy metal from wastewater by the pretreated and carbonation rice husk is comparatively better than untreated one because untreated adsorbent can further generate more problems like high chemical oxygen demand, low adsorption capacity, biological oxygen demand, total organic carbon due to release of organic compounds in the plant (rice husk) [12]. in this work, rice husks were investigated as a lowcost bio-sorbent alternative to prepare two forms of activated carbon using h2so4 or koh as an activating agent for pb2+ metal removal from aqueous solutions, and the three husk forms were compared to adjust any form that has higher adsorption capacity and best removal percentage. the research also contains equilibrium isotherms of adsorption and the kinetics that could be useful in the design and future operations. 2. experimental work 2.1. materials the nitrogen inert gas with a purity of 96% was used as inert medium gas in the process. sulfuric acid (h2so4) and potassium hydroxide (koh) with 97% of purity were used as a reagent. the polluted water pb2+ was simulated according to the heavy metals residues from the battery facto. the lead pb2+ ion aqueous stock solution was prepared by dissolving 0.16 g of lead (ii) nitrate (pb (no₃)₂), mw: 331.2 g/mol) in de-ionized water according to eq. 1, [13]. 𝑊 = 𝐶∗𝑀.𝑤𝑡∗𝑉 𝐴.𝑤𝑡∗106 (1) then the stock solution wita h concentration 100 ppm of pb2+ diluted to 20,40,60 and 80 ppm according to eq. 2: 𝐶1 ∗ 𝑉1 = 𝐶2 ∗ 𝑉2 (2) 2.2. rice husks preparation rice husks (rh) were gathered from a mill in the iraqi city of al-shamiya. rh is cleaned with de-ionized water and dried at 100 oc to guarantee that all volatile compounds and water were vaporized. then, 1kg of dried and cleaned rice husks was ground using the electrical grinder for 40 minutes. the powder produced sieve for 88 μm using apparatus of sieve analysis. fig.1 shows a diagram of the experimental installation of a system for the production of activated carbon (ac). the vessel (reactor) as shown in fig.1 that was installed inside the combustion furnace it was made from a cylinder of carbon steel with a diameter of 10 cm and a height of 15 cm. it features a cover that can be opened and closed with two nuts. several turns of stainless steel tube (1/4) inch in diameter are wrapped around the vessel, the lower end of the tube which is open inside the vessel, and the upper end is connected to the tube coming from the nitrogen cylinder. the regulator controlled the flow rate of nitrogen gas from the gas cylinder. the gas is then passed through a (1/4) inch pipe that is coiled around the vessel to ensure that the gas is preheated before flowing inside. the thermocouple and temperature recorder were attached to the effluent n2 gas line upside the furans [14]. figure 1. a diagram for the activation system. 60 grams of rh powder was put inside a crucible which is made from graphite, mineral wool is fixed on top of it and this was used to keep the powder from getting out with the gas during the burning process. then the graphite crucible is placed inner side of the vessel, which is located within the furnace. in the presence of nitrogen flow, the sample was precarbonized for 100 minutes at 280 oc in the furnace. the produced carbons were cool at 25 oc, and then impregnate with (4molar) of h2so4 or koh for one day. then the mixture was filtered to separate the solid material from the activation liquid by using filter paper and dried the sample to 100oc for three hours in the oven. the filtrate material was placed inside a crucible that was put in a vessel for activation. the vessel's temperature was kept at 650 oc for 140 minutes under nitrogen flow. after that, the activated carbon was allowed to cool to 25oc. the product of ac was cleaned by repeatedly washing with de-ionized water until the ph reached 7, and then dried in an oven at 105°c for 10 hours. murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 150 2.3. adsorption experiment the adsorption isotherms for lead pb2+ metal on the different kinds of rh prepared forms were examined at (25, 30, 35, and 40) oc. (100) ml of pb2+ solution at a specified concentration was mixed with (0.1) grams of different rh forms in a florence flask. then, the flask was put in a constant temperature hot plate magnetic stirrer. the tests of the adsorption equilibrium were done in two parts: firstly, the time of equilibration was determined by adding 0.1 grams of rh or its derivative to 100 ml of pb2+ solutions at a concentration of 100 ppm. the temperature and concentration of the solutions that were selected as the lowest temperature (25oc) and the greatest concentration (100 milligrams per liter), respectively. these settings indicate the greatest adsorption quantity that results in the highest length of time required for equilibrium to be reached under all of the variables that will be tested in the experiments. the mixture was vigorously stirred under the influence of reflux at a constant temperature of 25 oc. the test was repeated at different time intervals of 10, 20, 60, 80, and 100 minutes, after that, the filtrate solution was tested using atomic absorption spectroscopy aas to measure the concentration after the adsorption process. after 1 hour, solution concentrations had stabilized to within a little range. for the adsorption process, this duration is indicative of the equilibrium period. secondly, a series of tests were carried out to investigate the impact that temperature and initial concentration had on the adsorption of pb2+ from an aqueous solution onto the rh that had been previously prepared. to do this, a variety of concentrations were taken (20, 40, 60, 80, 100) ppm of pb2+ at different temperatures (25, 30, 35, 40) ◦c with a contact time of 1 hour. every single experiment was carried out by putting 0.1 gram of the adsorbent material (rh and its derivative) in a conical flask with (100 ml) of the solution of the heavy metal. after that, the adsorption procedure was carried out at the temperature that had been specified before, with continuous stirring for an hour. this procedure was repeated for each concentration at each temperature. at the end of the experiment's period, the solution was filtrated by the filtration apparatus and the filtrate was taken for analysis by aas. finally, the adsorbed amount qe (mg/g) of metals on the prepared rice husks was calculated by applying the material balance as in equation eq. 3, [15]: 𝐪𝐞 = ((𝐂𝟎 − 𝐂𝐞) ∗ 𝐕)/𝐖 (3) and the removal percentage was calculated from the following eq. 4: 𝐑𝐞𝐦𝐨𝐯𝐚𝐥 % = (𝐂𝐨 − 𝐂𝐞)/𝐂𝐨 ∗ 𝟏𝟎𝟎 (4) 2.4. kinetics of adsorption the study of kinetics is very important to explain the rate of adsorption. 0.1 gram of the adsorbents (rh and its derivatives of activated carbon) was put in the adsorption flask with (100 ml) of the highest concentration range (100 ppm) of the pb2+. the mixture was mixed under reflux at different temperatures (25, 30, 35, 40) ◦c. in each experiment, 5 ml samples of the solution were taken at different periods. these samples were analyzed for pb2+ concentration. this routine was continued until the equilibrium state was reached. the equilibrium state was attended when the concentration of two successive samples are approximately equal. 3. result and discussion 3.1 characterization of adsorbents (fesem and bet) the rh and its derivatives were identified by several test techniques. these checkup procedures include fesem and bet. 3.1.1 characterization of rh fesem was used to characterize the morphology of the prepared rh in the form of powder by obtaining structural photos and micrographs. fig.(2) shows fesem images of the prepared (rh) without any activation. the analysis revealed an almost smooth surface with a small number of pores and cavities. it could be concluded from these that the content has a small surface area available for the adsorption process. these findings are in line with those found by several other studies [16]. the bet test of the prepared rh without activation was found to be with a bet surface area of (20.5025 m²/g) and an average pore diameter of (4v/a by bet) 8 .90682 nm. it could be expected that this low surface area has a significant diverse effect on the adsorption. the low surface area could be contributed to the high pore sizes. the large size of the pores provides a low surface area while the small size does the reverse. furthermore, there is a large number of cellulose materials that close pores of small diameters. 3.1.2 characterization of (rhac) fig. (3) shows the fesem result of the rh that was pre-treated with acidic solution h2so4. figure 3. fesem images for prepared rhac, at 10 kx. it is clearly shown in this figure that the pre-treatment with h2so4 and carbonization causes the rice husks to become more amorphous and porous. figure 2. fesem images for prepared rh, at 10 kx. murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 151 rhac has a porous structure with a random distribution of distinct pore diameters. furthermore, this figure shows that activated carbons made from rh waste have a heterogeneous rough surface with a random distribution of cracks and cavities, as well as porosity and that there is a considerable chance that the pores will attract and absorb heavy metal molecules. these findings are in line with those of several other studies [17], with different raw materials. the bet test of the activated carbon of rice husks that were pretreated with h2so4 was observed to be with bet surface area equal to (561.7827 m²/g) and the average adsorption pore diameter of (4v/a by bet) 2 .62941 nm and it could be noticed that a higher surface area was achieved by acid activation than the surface area of rice husk without activation. furthermore, the observed reduction of pore size indicates that the cellulose material was degraded by acidic activation. hence, more fine pores were opened and more surface area was available for adsorption. these surfaces enhance the adsorbent for adsorption of adsorbates on the active sites for the heavy metal to be captured and absorbed via these pores. 3.1.3 characterization of (rhbc) fig. (4) shows the fesem test of the activated carbon of rice husk pretreated with basic solution koh figure 4. fesem images for prepared rhbc, at 10 kx. it is clearly shown that the pre-treatment with koh and the carbonization make the rice husks more porous and amorphous. rhbc has a more good porous structure, random arrangement, and different sizes of pore. the rhbc has a heterogeneous rough surface with a random pattern of cracks and cavities with porosity, as shown in fig. (4.8), and there is a considerable chance that heavy metal molecules will be trapped and adsorbed into these pores. these findings are in line with those of several other studies (patel, asatkar, et al. 2019). the bet test of the activated carbon which was prepared from rice husks and pretreated with hydroxide potassium (koh) has a bet surface area equal to (721.7400 m²/g), in addition, the adsorption average pore diameter was (4v/a by bet) equals to 3 .60725 nm. it could be noticed that the activation with koh gave the best result and a higher surface area for the heavy metal to be adsorbed and trapped in these pores. 3.1.4 comparison between adsorbents it was noticed clearly that the activation procedure resulted of the opening of confined pores and the reduction of carbonaceous material aggregates. the activation process clearly shows that the carbonized waste materials (rice husks) become well developed and porous due to the extremely hightemperature treatment and the action of chemical activation agents. the activated carbons that are prepared from rice husks rhbc and pretreated with basic koh agent have more uniform surfaces of homogeneously arranged pattern with high porosity that is responsible for high surface area because the koh is a strong base agent. while natural rice husks (rh) and acidic activated carbon rhac that are activated with acid agents have lower porosity and less heterogeneous rough surface with a random distribution of fractures and voids. therefore, the activated carbon prepared from rice husks (rhbc) with koh as an activation agent gave a good pore diameter (2.62941 nm) and bet surface area (720.8293) in comparison with rh and rhac. the smallest diameter and the bigger surface area make the rhbc the best for the adsorption of molecules of the heavy metal to be sucked into and adsorbed. 3.2 equilibrium of adsorption the combination of isothermal information analysis and isothermal characteristic modeling has made tremendous progress in finding the most appropriate model for design. figures (5-7) demonstrate the adsorption equilibrium isotherms for lead pb2+ various temperatures on rh, rhac and rhbc. these curves plotted at different temperature (25, 30, 35, 40) oc for a range of concentration of pb2+ (20-100) ppm. these figures clearly show that all curves for pb+2 on rh and its derivate forms identical in nature and have the classical adsorption isotherm type 1 shape. this indicates that when the concentration of pb2+ ions in the solution rises, so does the concentration on the adsorbent's surface. these results also show that the concentration in the solution and the concentration in the adsorption phase have a proportionate connection. however, this proportional declines and the adsorbed phase concentration reaches a constant value when the adsorbent reaches its maximum capacity at a large concentration of pb2+ ions in the solution. figure 5. adsorption equilibrium isotherms for pb2+ ion adsorbed on the rh at temperatures range (25-40) co. figure 6. adsorption equilibrium isotherms for pb2+ ion adsorbed on the rhac at temperatures range (25-40) co. murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 152 figure 7. adsorption equilibrium isotherms for pb2+ ion adsorbed on the rhbc at temperatures range (25-40) co. the previous figures and table show that the maximum value of qe (mg/g) at 25oc decreased as the temperature increased, while the best value of adsorption was found for rhbc then followed by rhac and rh, respectively. this conclusion is consistent with a prior study conducted by[18]. the experimental results were correlated to the most well-known adsorption isotherms that describe the adsorption of solutes from aqueous solutions onto rh, rhac, and rhbc. these equations are known as langmuir and freundlich isotherms [19]. the langmuir adsorption isotherm describes solute adsorption on a solid adsorbent that is limited to a single monolayer of solute molecules. this is based on the langmuir adsorption assumption, which assumes that the solid adsorbent's surface has a homogeneous surface. on the other hand, the langmuir adsorption isotherm equation could be represented mathematically as follows [20]: qe = qm kl ∗ ce 1+kl ce freundlich adsorption isotherm illustrates the multilayer adsorption of a solute onto the heterogeneous surface of a solid adsorbent. mathematically, the equation for the freundlich adsorption isotherm is as follows [21]: qe = kf ce 1 n the linear formulations of the langmuir and freundlich adsorption isotherm equations were as follows eqs. 4 and 6, [22] : langmuir: ce/qe = ce/qm + 1/(kl qm) (5) freundlich: 𝑙𝑜𝑔 𝑞𝑒 = 𝑙𝑜𝑔 𝐾𝑓 + 1 𝑛 𝑙𝑜𝑔 𝐶𝑒 (6) according to equations (5) and (6), the langmuir and freundlich adsorption isotherms were plotted for adsorption of pb2+ onto rh, rhac rhbc in their linear forms in figures (8-13). figure 8. langmuir adsorption isotherm model for pb2+ ions adsorbed on rh . figure 9. langmuir adsorption isotherm model for pb2+ ions adsorbed on rhac. figure 10. langmuir adsorption isotherm model for pb2+ ions adsorbed on rhac figure 11. freundlich adsorption isotherm model for pb2+ ions adsorbed on rh at (25-40) co. murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 153 figure 12. freundlich adsorption isotherm model for pb2+ ions adsorbed on rhac at (25-40) co. figure 13. freundlich adsorption isotherm model for pb2+ ions adsorbed on rhbc at (25-40) co. the average values of confidence level (r2) are shown in table (1) for langmuir and freundlich isotherm models for the adsorption of pb2+ on prepared rh and its activated forms. the comparison of (r2) values for the two isotherm models provide evidence that the freundlich adsorption isotherm more accurately predicts the experimental results than the langmuir adsorption isotherm. therefore, it was concluded that the adsorption of pb2+ on all forms of rice husks is limited to a multilayer and all forms of prepared rice husks have heterogeneous surface and every layer of these represent the adsorption as in a single layer. this conclusion is consistent with the findings of a prior study conducted by [23], who concluded that the adsorption of zinc heavy metals onto phosphoric acidactivated rice husk follows the freundlich isotherm. table 1. average confidence interval levels (r2) for langmuir and freundlich models. adsorbents r2 langmuir model r2 freundlich model rh 0.973 0.994 rhac 0.979 0.993 rhbc 0.937 0.987 3.3 kinetic of adsorption figures (14 to 16) represent the amount adsorbed pb2+ on to different types of prepared rh and its activated carbon form as a function of the progression of time for the range of temperature (25–40) oc. figure 14. rate of adsorption of pb2+ on rh figure 15. rate of adsorption of pb2+ on rhac figure 16. rate of adsorption of pb2+ on rhbc these figures show that the amount adsorbed of the pb2+ heavy metal increases rapidly in the first fifteen minutes. after that, the change of the amount adsorbed is not significant until reaching the equilibrium state. the large concentration of adsorbable solute molecules and the availability of empty active sites in pores on the adsorbent may explain the rapid rate of adsorption in the early stages. the experimental adsorption data of the current investigation were correlated using pseudo 1st order and pseudo 2nd order kinetics adsorption models. the adsorption kinetic models could be rewritten in linear form as shown in the following formulas [24]: 1st order: 𝐥𝐨𝐠(𝐪𝐞 − 𝐪𝐭) = 𝐥𝐨𝐠 (𝐪𝐞) − 𝐊𝟏/𝟐. 𝟑𝟎𝟑 ∗ 𝐭 (7) 2nd order: 𝐭/𝐪𝐭 = 𝟏/(𝐊𝟐 ∗ 𝐪𝐞^( 𝟐) ) + 𝟏/𝐪𝐞 ∗ 𝐭 (8) murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 154 figures (17 22) illustrate the kinetics experimental data fitting with linearized form of pseudo 1st order and pseudo 2nd order kinetics models, for iron, lead, and zinc heavy metals adsorption on various types of prepared rice husks. figure 17. first order kinetic model for the adsorption of pb2+ on rh at different temperature figure 18: first order kinetic model for the adsorption of pb2+ on rhac at different temperature figure 19. first order kinetic model for the adsorption of pb2+ on rhbc at different temperature figure 20. second order kinetic model for the adsorption of pb2+ on rh at different temperature figure 21. second order kinetic model for the adsorption of pb2+ on rhac at different temperature figure 22. second order kinetic model for the adsorption of pb2+ on rhbc at different temperature it's also possible to see how a pseudo-2nd-order model depicts experimental data by identifying the confidence level (r2) for the chosen equations. the confidence level for pseudo-second-order models has a high value of 0.998 while the confidence level of the pseudo-first-order is 0.987 this demonstrates that the pseudo 2nd order model accurately represents the experimental data. table (2) show the pseudo 1st order & 2nd parameters of the adsorption of pb2+ on the three types of prepared rice husks at different temperatures. these findings are consistent with prior studies. they applied pseudo 1st order and 2nd order models for metals removal murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 155 from wastewater. they concluded that the 2nd order kinetic model fits the data well with an r2 of 0.993. table 2. average confidence interval levels (r2) for pseudo first order and pseudo second order. adsorbents r2 pseudo first order r2 pseudo second order rh 0.981 0.994 rhac 0.984 0.993 rhbc 0.987 0.998 3.4 the effect of the initial concentration the initial concentration of the adsorbate is a crucial factor for determining adsorption capacity and adsorbate removal percentage. the equation (4) was used to calculate the removal percentage: the initial concentrations of lead and pb2+ in the solutions are plotted as a function of removal percentage due to adsorption on the surfaces of rh, rhac, and rhbc in figures (23 to 25). figure 23 . removal percentage of pb+2 on rh versus initial concentration at temperature (25-40) co figure 24. removal percentage of pb+2 on rhac versus initial concentration at temperature (25-40) co figure 25. removal percentage of pb+2 on rhbc versus initial concentration at temperature (25-40) oc the increase of the initial concentration of the pb2+ metal in the solution associated with a decrease in the removal percentage was demonstrated in these figures. however, increasing the initial concentration improves adsorption capacity while decreasing the percentage of pb2+ removed. these phenomena could be explained by monitoring the ratio of adsorbed molecules in the solution of the available active sites of the adsorbent. the removal percentage increases as this ratio decreases since the adsorbable molecule in the solution's chance to attach the active site on the adsorbent decreases. therefore, for low pb2+ ions concentrations in solutions, the initial number of metal molecules to available adsorbent surface area is small, while for large concentrations of heavy metals in solution, the number of accessible adsorption sites number decreases as the saturation state of the adsorption sites approaches. in comparison with this result, the study done used activated carbon of rice husks pre-treated with a basic agent as an effective adsorbent for removing different metals fe2+ and pb2+ from aqueous solutions. for concentration range (5-100) ppm. they concluded that the removal percentage of fe2+ and pb2+ was 94.42% and 90.36% respectively. 4. conclusion in this research, activated carbon with a high surface area and high adsorption capacity was produced using no high temperature. the results demonstrate that rhac or rhbc produces activated carbon with a high adsorption capacity, a porous structure, and a surface area of various shapes and sizes according to fesem and bet tests. this study shows that the activated carbon rhbc has the highest rate for pb2+ removal from wastewater compared with rh or rhac. the pb2+ metal shows good adsorption capacity at 25oc and as the temperature increases the adsorption efficiency decrease because increasing the temperature leads to an increase in the kinetic energy of the molecules adsorbed on the adsorbent surface, which leads to an increase in the possibility of their separation from the adsorbent surface and back into the solution. the adsorption isotherm data were well fitted by freundlich isotherm, for pb2+ ions. the results revealed a sharp rise in adsorption rate initially until equilibrium is achieved. with a confidence level of 0.99, the pseudo-second-order model accurately reflected the data. the results of this investigation will be useful for the removal of pb2+ metal by rice husks from battery manufacture wastewater. acknowledgment the authors like to express their gratitude to the members of the chemical engineering department, college of engineering, al-qadisiyah university, for their technical assistance in completing this study. murtadha hamid khashan, abbas khalaf mohammad /al-qadisiyah journal for engineering sciences 15 (2022) 148–156 156 references [1] abdel halim, a., k. el-ezaby and m. el-gammal (2019). "removal of fe2+ and pb2+ ions from wastewater using rice husks-based adsorbents." journal of egyptian academic society for environmental development. d, environmental studies 20(1): 47-60. [2] aljeboree, a. m., a. n. alshirifi and a. f. alkaim (2017). "kinetics and equilibrium study for the adsorption of textile dyes on coconut shell activated carbon." arabian journal of chemistry 10: s3381-s3393. [3] bratby, j. (2016). coagulation and flocculation in water and wastewater treatment, iwa publishing. [4] carraro, e., s. bonetta and s. bonetta (2017). "hospital wastewater: existing regulations and current trends in management." hospital wastewaters: 1-16. [5] chuah, t. g., a. jumasiah, i. azni, s. katayon and s. t. choong (2005). "rice husk as a potentially low-cost biosorbent for heavy metal and dye removal: an overview." desalination 175(3): 305-316. [6] dada, a., a. olalekan, a. olatunya and o. dada (2012). "langmuir, freundlich, temkin and dubinin–radushkevich isotherms studies of equilibrium sorption of zn2+ unto phosphoric acid modified rice husk." iosr journal of applied chemistry 3(1): 38-45. [7] ghosal, p. s. and a. k. gupta (2017). "determination of thermodynamic parameters from langmuir isotherm constant-revisited." journal of molecular liquids 225: 137-146. [8] gonzález-garcía, p. (2018). "activated carbon from lignocellulosic precursors: a review of the synthesis methods, characterization techniques, and applications." renewable and sustainable energy reviews 82: 1393-1414. [9] gratuito, m., t. panyathanmaporn, r.-a. chumnanklang, n. sirinuntawittaya and a. dutta (2008). "production of activated carbon from coconut shell: optimization using response surface methodology." bioresource technology 99(11): 4887-4895. [10] gupta, v. k., p. carrott, m. ribeiro carrott and suhas (2009). "low-cost adsorbents: a growing approach to wastewater treatment—a review." critical reviews in environmental science and technology 39(10): 783-842. [11] jabbar, a. r. and a. k. mohammad (2020). "comparative study for adsorption of acidic and basic dyes on activated carbon prepared from date stone by different activation agent." al-qadisiyah journal for engineering sciences 13(1). [12] kilic, m., e. apaydin-varol and a. e. pütün (2011). "adsorptive removal of phenol from aqueous solutions on activated carbon prepared from tobacco residues: equilibrium, kinetics, and thermodynamics." journal of hazardous materials 189(1-2): 397-403. [13] kushwaha, a., r. rani and j. patra (2020). "adsorption kinetics and molecular interactions of lead [pb (ii)] with natural clay and humic acid." international journal of environmental science and technology 17(3): 1325-1336. [14] liu, j., y. li, b. zhang, j. cao, z. cao and j. domagalski (200 9). "ecological risk of heavy metals in sediments of the luan river source water." ecotoxicology 18(6): 748-758. [15] ngah, w. w. and m. m. hanafiah (2008). "removal of heavy metal ions from wastewater by chemically modified plant wastes as adsorbents: a review." bioresource technology 99(10): 3935-3948. [16] nhapi, i., n. banadda, r. murenzi, c. sekomo and u. wali (2011). "removal of heavy metals from industrial wastewater using rice husks." the open environmental engineering journal 4(1). [17] patel, a. r., a. asatkar, g. patel and s. banerjee (2019). "synthesis of rice husk derived activated mesoporous carbon immobilized palladium hybrid nano‐ catalyst for ligand‐free mizoroki‐heck/suzuki/sonogashira cross‐coupling reactions." chemistryselect 4(19): 5577-5584. [18] paulino, a. t., l. b. santos and j. nozaki (2008). "removal of pb2+, cu2+, and fe3+ from battery manufacture wastewater by chitosan produced from silkworm chrysalides as a low-cost adsorbent." reactive and functional polymers 68(2): 634-642. [19] revellame, e. d., d. l. fortela, w. sharp, r. hernandez and m. e. zappi (2020). "adsorption kinetic modeling using pseudo-first order and pseudo-second order rate laws: a review." cleaner engineering and technology 1: 100032. [20] shamkhi, h. a., a. d. albdiri, f. a. jabir and d. petruzzelli (2022). "removal of pb2+, cu2+, and cd2+ ions from a saline wastewater using emulsion liquid membrane: applying response surface methodology for optimization and data analysis." arabian journal for science and engineering 47(5): 5705-5719. [21] sharma, y. and s. upadhyay (2011). "an economically viable removal of methylene blue by adsorption on activated carbon prepared from rice husk." the canadian journal of chemical engineering 89(2): 377-383. [22] taha, m. f., c. f. kiat, m. s. shaharun and a. ramli (2011). "removal of ni (ii), zn (ii) and pb (ii) ions from single metal aqueous solution using activated carbon prepared from rice husk." international journal of environmental and ecological engineering 5(12): 855-860. [23] tan, i., a. ahmad and b. hameed (2009). "adsorption isotherms, kinetics, thermodynamics and desorption studies of 2, 4, 6-trichlorophenol on oil palm empty fruit bunch-based activated carbon." journal of hazardous materials 164(23): 473-482. [24] tay, t., s. ucar and s. karagöz (2009). "preparation and characterization of activated carbon from waste biomass." journal of hazardous materials 165(1-3): 481-485. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٠٦ effect of water head on the infiltration characteristics by using the laboratory tests dr. mohammed sh. m. al shakerchy / lecturer engineering college / university of kufa abstract the infiltration characteristics of the soil are an important component of the hydrological conditions. they are one of the components of the water balance and are necessary to describe the runoff response by a runoff model, in addition to describe the effect of water movement on the changing of the soil properties within infiltration. the present work emphasis on the characteristics of the infiltration by using laboratory model. this model is performed on the remoulded sample of specific density for different heads of water, 10, 20, and 30cm. the results revealed that there are significant effect of the water head with high interaction of the wetting conditions of the soil sample. a comparison was made with the results of field infiltration work, made by mohammed sh. al shakerchy, 2006. a statistical analysis was made to develop a relationship among the different studied parameters and between the field and laboratory works. keywords: soil, infiltration, rate of infiltration, water head, seepage. مختبریةالفحوصات التأثیر ارتفاع الماء على خصائص الترشح باستخدام مدرس/ محمد شاكر محمود الشكرجي . د al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٠٧ جامعة الكوفة/ كلیة الھندسة الخالصــة إن خصائص الترشح للتربة ھي من مركبات الظروف الھیدرولوجیة، حیث إنھا من مركبات التوازن ھي أیضا ضروریة لوصف المیاه الجاریة فوق السطح في المودیالت الصغیرة، باإلضافة إلى وصف المائي و .دور حركة الماء في تغییر خصائص التربة التي یخترقھا الماء ھذا المودیل تم على نموذج تربة مقولب . العمل الحالي یؤكد على خصائص الترشح باستخدام المودیل المختبري النتائج كشفت انھ ھناك تأثیر واضح . سم ٣٠، و٢٠، ١٠ة لعمود ماء بارتفاعات مختلفة، بكثافة معینة معرض تم مقارنة النتائج مع عمل حقلي من قبل محمد . الرتفاع عمود الماء مع ارتباط بحالة الترطیب لنموذج التربة صائص المدروسة، قمنا بتحلیل إحصائي للنتائج لتطویر عالقة ریاضیة لمختلف الخ. ٢٠٠٦شاكر الشكرجي، أیضا بین العمل الحقلي والمختبريو ssymbol sp: poorly graded sand; i: cumulative infiltration in cm3/cm2; t: time; a, b, c, and d: constants; h: water head; uscs: unified soil classification system. introduction the movement of water into soil is called infiltration, whereas, downward movement of water within the soil is called percolation. the movement of water in soils is a complicated phenomenon to be described because soil surfaces interact with the water being transferred and the soil changes during the water movement process. water can move in either the liquid or vapor phase, with the latter being more important for relatively dry soil. various driving forces in water flow exist in the soil, including differences in water content, salt content, temperature, and void size distribution. an overall description is required to encompass this flow system.[4] water movement or moisture transfer in soils may be divided into two particular systems for general consideration: -[4, 12, 13] a) the saturated system where all the voids are filled with water, and b) the partially saturated system where both air and water are present. for partly saturated soils, the mechanism for moisture transfer will depend upon whether the system is relatively dry or relatively wet. in the former, vapor transfer is al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٠٨ greater than liquid transfer. this is especially important if large temperature gradients exist. in the latter case, where the soil-water system is relatively wet, liquid transfer is generally considered as viscous flow. diffusive flow due to physicochemical gradients is generally taken to be minor and insignificant in computations of liquid transfer. the absence of a vapor phase in saturated systems indicates that the movement of water in such systems is effected solely by liquid transfer.[4, 12, 13] water entering a dry soil at the surface does not saturate the soil below and moves through unsaturated soil. “unsaturated flow is thus the most common type of flow in soils”, but saturated flow is generally easier to describe. even “saturated” soil rarely has all its voids filled with water. it is no unusual to expect from 2 to 12 percent of air remaining in the voids.[4, 8] in groundwater and seepage problems the soil mass is considered as a homogeneous medium of interconnected pores. a material is said to be porous if it contains void spaces in which the material is absent. pore spaces can be discontinuous or entirely continuous. sands as an example of porous material are composed of microscopic particles that may be rounded, sub-angular or angular in shape. numerous voids of varying shapes and sizes exist between the individual particles. each pore is connected by constricted channels to other pores. in steady-state flow, the soil is assumed as near to being saturated as possible to allow for the flow to occur.[4] introduction into soils in the field: infiltration is the downward entry of water into the soil. the infiltration rate is the rate at which a soil, in a given condition, can absorb water. it is defined as the volume of water passing into a unit area of soil per unit time, with dimensions of velocity (lt-1). the infiltration velocity is the actual volume of water moving downward into the soil per unit area per unit time.[4] the infiltration rate obviously depends upon both surface and subsurface conditions. the most important for infiltration rate is stability of pores in the surface layers of soil and water transmission rate of the soil body. either the surface or the subsurface may limit infiltration rate, and their relative importance depends upon the particular soil. the initial water content of the soil has a large influence on initial infiltration.[4] al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٠٩ the infiltration rate is generally highest when the soil is dry. as the soil becomes wet, the infiltration rate slows to the rate at which water moves through the most restrictive layer, such as a compacted layer or a layer of dense clay. infiltration rates decline as water temperature approaches freezing. little or no water penetrates the surface of frozen or saturated soils.[10, 12] an ideal infiltration curve, based on theoretical analysis, is illustrated in fig. 1, whereas fig. 2 shows the ideal infiltration rate with time.[10, 12] the internal water movement in most gypseous soils is normally moderate to rapid, except where gypsum incrusted layers impede the downward movement of water.[11] permeability also varies with soil texture. permeability is generally rated from very rapid to very slow. this is the mechanism by which water reaches the subsoil and rooting zone of plants. it also refers to the movement of water below the root zone. water that percolates deep in the soil may reach a groundwater aquifer.[11] infiltration measurements are usually made to determine the infiltration rate, which is significant in irrigation and hydrologic studies. this rate decreases with time and tends to approach a constant value. all the information can be shown on a graph of cumulative infiltration versus time. several empirical equations adequately fit many measurements: -[4] …(1) i = a. tb or: i = ct1/2 + d …. (2) where i is the cumulative infiltration in cm3/cm2; t is time; a, c, and d are constants. the constant b is found to be about 0.5 in many measurements of water movement into dry soil where suction forces predominate and gravitational forces are negligible, in wet soils the constant b approaches 1.0.[4] laboratory work preparation of the laboratory work the work was included a set of laboratory infiltration tests on a remoulded sample from certain location in al-najaf city. the sample was remoulded in a special container had been made for this work as detailed below. the tests was made by al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٠ subjection the surface of the remoulded sample to the head of water and observation the lowering of the water surface at certain period of time which refers to the infiltration of water into the soil. the head of water above soil surface was varying to study the effect of the head on the infiltration characteristics, the water heads were 10, 20, and 30 cm where the remoulded soil sample was of 10 cm in thickness. materials and equipment the laboratory model consists of rectangular cross section metal container of dimensions 41cm x 40.5cm x 100cm depth, as shown in fig. (3) and plate (1). the remoulded soil sample, which was collected manually from al adalah district in al najaf city, was placed in the container with constant thickness of 10 cm. table (1) illustrates the properties of the soil used in the tests. figure (4) shows the results of the grain size distribution of the sample, the figure obviously shows that the soil is within the sand range where sand is more than 85 % of the sample. the soil is classified as sp according to unified soil classification system (uscs) the water used in the infiltration tests was potable from water supply of the laboratory with total dissolved salts (tds) is 920 ppm. test program table (2) illustrates the program of the tests with time of start and end of the flooding process to form the water head on the soil sample, and then monitoring the lowering of the water head with time. the program included three tests for different values of the water head. the first and second tests was performed at one day period where the third one was performed after 3 days period from the second one. the average time period of the flooding process for the first and second tests was about 3 minutes and 8 minutes for the third one. results and discusion results of test no. 1 figure (5) shows the results of first test with water head of 10 cm subjected to the remoulded soil sample in the container, the figure illustrates the relationship between the cumulative infiltration in mm and cumulative respective time in minute. one can notice that the infiltration decreases with time because of the wetting processes of the soil, and this is compatible with the ideal field one which describe the infiltration behavior through the soil in field, figure (1), but the values of infiltration al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١١ in laboratory are less than that in the field and this behavior may caused by the limitations of the infiltration in vertical direction only, while in field, all directions are available. the infiltration continued in decreasing until the next day. figure (6) shows the relationship between the infiltration rate (infiltration divided by the time) in mm/minute and time in minutes for head of water equal to 10 cm. it is clearly that this relationship is in decreasing trend with progress of time start from relatively high value, in comparison with the field ideal infiltration rate, figure (2), it is close to the ideal initial dry curve and that is quite true for the condition of the remoulded soil sample. results of test no. 2 figure (7) shows the results of second test with water head of 20 cm subjected to the remoulded soil sample in the container, the infiltration changes in a straight trend and that means the infiltration in this case changed with a constant value and that may caused by the wetting situation of the soil, this curve represent a part of the ideal field infiltration, figure (1), which describe the infiltration behavior through saturated zone. the behavior of infiltration in this test, differs from the first one in trend and values, may affected by the changing of the soil structure that caused by the first one in addition to the wetting processes. the infiltration continued in decreasing until to the next day. figure ( 8) shows the relationship between the infiltration rate (infiltration divided by the time) in mm/minute and time in minutes for head of water equal to 20cm. one can notice that there are approximately constant rate of infiltration with progress of time within narrow range of values (0.12-0.16 mm/min.). in comparison with the field ideal infiltration rate, figure (2), it is close to the ideal initial wet curve and that is quite true for the condition of the remoulded soil sample. results of test no. 3 figure (9) shows the results of third test with water head of 30 cm subjected to the remoulded soil sample in the container, the infiltration changes in a straight trend and faster than the previous one, and that may caused by the higher water head (30cm) and also because of there were specific change in soil structure that cause by the leaching process in addition to the al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٢ wetting situation of the soil, while the third test performed after about three days period from the second one and this may be enough to dry the sample in the model, where the dry soil situation is increasing infiltration. this curve represent a part of the ideal field infiltration, figure (1), which describe the infiltration behavior through saturated zone. the infiltration continued in decreasing until to the next day figure (10) shows the relationship between the infiltration rate (infiltration divided by the time) in mm/minute and time in minutes for head of water equal to 30cm. one can notice that there are drop in the rate of infiltration within the first 100 minutes of the infiltration then the rate reaches a constant value of about 0.3 mm/minute. this situation of rate verifies the condition of the soil, where the soil change from proportionally dry to wet conditions. the comparison with the field ideal infiltration rate, figure (2), revealed the condition of soil that discussed above. comparison of different cases figure (11) shows the results of infiltration with time for different water heads. it is obviously that the case of 10cm water is faster than the case of 20cm water especially at start and that rebound to the wet condition of the soil, where the soil was initially dry at case of 10cm water and wetted with progress of infiltration where the two cases of 10cm and 20cm closes to each other at the late time of infiltration. the case of 30cm water is unique, where the infiltration stay higher one in spite of the changing of wetting condition of the soil but with high water head with respect to other cases. figure (12) shows the results of the rate of infiltration with time for different water heads. the figure represent clearly the interaction effect of condition of the soil wetting and water head, where the quick rate of infiltration corresponded to the high water head but the wetting condition decreases the rate of infiltration for the case of 20cm water with respect to the lowest water head (10cm) with considering the time period between the two cases where the period between first and second cases was al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٣ about 24 hours and the period between the second and third cases was about three days. statistical analysis a statistical analysis was made to relate the different parameters which studied in the research, infiltration, water head, and time. the analysis depends on the development of ideal infiltration equation (eq. 3) as following: [ ]btai ×= … (3) the coefficients of the equation presented as variables depending on the water head as following in eqs. (4) and (5): a = 0.626 ln( h ) + 2.511 ( r2 = 0.61 ) … (4) b = 0.308 ln( h ) – 0.1554 ( r2 = 0.963 ) .. . (5) where: h: water head and field infiltration comparison between laboratory figure (13) shows a comparison between the results of field and laboratory tests for infiltration. the field work was performed by mohammed sh. al shakerchy[1] on al najaf city soil in the main intersection of the city (near the 20th revolution square) to find out the characteristics of infiltration and its effect on the strength characteristics. the soil was classified as sp according to uscs. the test was made by fill a pit of dimensions 5.5m x 8m with water using a tank vehicle of 8000 liter, then the water infiltrations were recorded with time. the test was repeated 15 times. it is clear that there is large difference between the two models and that may rebound to many reasons like the conditions of soil and environment. the properties of the soil (density, permeability, structure, stratification, …etc) have the main effect on the infiltration which some of these properties affect positively like permeability and others affect negatively like density and stratification. the conditions of environment represented in the temperature of the weather, where the increase in water temperature decrease the viscosity of the fluid and increase the infiltration and in the same time, the high temperature causes the evaporation process of the water. these conditions are controlled in the laboratory and can change for different conditions of the field oppositely the uncontrolled field conditions. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٤ in the laboratory model the infiltration was limited in the vertical direction only where the field test was unlimited in specific direction and this is the main reason of high difference between the two models. figure (14) shows the relationship between the time and the percent of the laboratory infiltration to the field infiltration. this relationship is in increasing trend with time. equation (2) relate the percentage ratio of the laboratory to the field infiltration with time and r2 =0.91. this equation is useful to predict the field infiltration from the laboratory work. conclusions from the previous articles, the following points are concluded: 1there were clear effect of the water head, that subjected to a soil, on the infiltration, processes and the rate of the infiltration where with increasing the water head, the infiltration increases with same initial conditions of the soil. 2the infiltration and rate of infiltration are change with time where the wet condition of the soil was progressing and that is for all tests of all different water heads. 3there were a huge difference between the laboratory and field results and that is return to different causes, such as, the soil conditions, which includes the density and permeability, and the temperature of the water. the infiltration in the field conditions is included the entering of water into the soil in different directions where the infiltration in laboratory conditions is restricted in vertical direction only. 4as a result of the statistical analyses on the laboratory work, an equation was found to relate the time, infiltration, and water head with good r2. 5 a good equation with acceptable r2 (0.91) relate the laboratory work and the work. acknowledgment al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٥ special thanks to engineers ban salam and ghadeer jasim for their efforts in the completion of the tests in this research. rffernces 1. al shakerchy, m. sh., 2007, "geotechnical properties of al najaf city soil with emphasis on the infiltration and strength characteristics", ph. d. thesis, building and construction dept., university of technology, baghdad, iraq. 2. houch, b. k., 1969, "basic soil engineering", 2nd ed., john wiley and sons, new york. 3. muskat, m. 1946. “the flow of homogeneous fluids through porous media” j.w. edwards publisher, inc. ann arber, 2ed edition 4. raymond n. yong and benno p. warkentin, 1975, “soil properties and behavior”, book of development in geotechnical engineering, vol. 5, pp. 141195, elsevier scientific publishing company, amsterdam, netherlands. 5. reeve, r.c. 1957. “drainage investigation methods in drainage of agricultural lands” american society of agronomy; 6. robert, a. greenkorn 1983.”flow phenomena in porous media” marcel dekker, inc. new york and basel. ch. 1, p 5; 7. roger, j. m. de wiest, 1969. “flow through porous media” academic press new york and london, ch.2, p 55. 8. roy, m, cote, j. kourand, m. and report, c. 1996. “characterization of unsaturated granular bases for drainage consideration during spring thaw” international symposium on thin pavements, surface treatments and unbound roads, int. 9. weber, ernest m. and a.a hassan 1972. “role of models in groundwater management”, water resources bulletin, journal of the american water resources association, minneapolis, minn., vol. 8, no.1, pp.198-206; 10. http://www.carleton.edu/departments/geol/davestella/water/soil%20water/so ".modeling the soil water systemil_water.htm, " 11. “.gypseous soilsp://www.fao.org/docrep/to323e/to323e02.htm, “htt 12. water http://www.dasnr.okstate.edu/soilphysics/noplugin/water/infil.html, " ".movement in soil 13. water -http://edis.ifas.ufl.edu/ss110, "movement of water: basics of soil al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٦ ".part iii -relationships table (1): properties of the soil used in tests. soil density, gm/cm3 specific gravity water content, % void ratio, e 1.8 2.68 10 0.638 table (2): tests program. test no. water head, cm date time of flooding start time of flooding end 1 10 14/2/2007 10:48 am 10:51 am 2 20 15/2/2007 09:32 am 09:35 am 3 30 18/2/2007 10:32 am 10:40 am note: all soil samples with thickness of 10cm. time figure (1): ideal infiltration curve.[10, 12] al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٧ figure (2): ideal infiltration rate curve.[10, 12] bhorizontal plan avertical section figure (3): details of the container. ٍ◌soil sample water head container holed side ٤٠.٥ cm ٤١ cm al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٨ plate (1): the metal container., 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 sieve opening, mm, log scale p a ss in g p er ce n t, % d10= 0.13 d30= 0.34 d60=0.8 figure (4): grain size distribution of the soil used in the tests. 0 10 20 30 40 50 60 0 50 100 150 200 cumulative time, min. c u m u la ti v e in fi lt ra ti o n , m m figure (5): relationship between cumulative infiltration and time for water head of 10 cm. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧١٩ 0 0.1 0.2 0.3 0.4 0.5 0 50 100 150 200 cumulative time, min. in fi lt ra ti o n r a te , m m /m in . figure ( 6): relationship between infiltration rate and time for water head of 10 cm. 0 10 20 30 40 50 60 0 50 100 150 200 250 cumulative time, min. c u m u la ti v e in fi lt ra ti o n , m m figure ( 7): relationship between cumulative infiltration and time for water head of 20 cm. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٠ 0 0.1 0.2 0.3 0.4 0.5 0 50 100 150 200 250 cumulative time, min. in fi lt ra ti o n r a te , m m /m in . figure ( 8): relationship between infiltration rate and time for water head of 20 cm. 0 10 20 30 40 50 60 0 50 100 150 200 250 cumulative time, min. c u m u la ti v e in fi lt ra ti o n , m m figure ( 9): relationship between cumulative infiltration and time for water head of 30 cm. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢١ 0 0.1 0.2 0.3 0.4 0.5 0 50 100 150 200 250 cumulative time, min. in fi lt ra ti on r at e, m m /m in . figure ( 10): relationship between infiltration rate and time for water head of 30 cm. 0 10 20 30 40 50 60 0 50 100 150 200 250 cumulative time, min. in fi lt ra ti on , m m water head = 10cm 20cm 30cm figure (11): relationship between cumulative infiltration and time for different water heads. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٢ 0 0.1 0.2 0.3 0.4 0.5 0 50 100 150 200 250 cumulative time, min. in fi lt ra ti on r at e, m m /m in . water hieght = 10 cm 20 cm 30 cm figure( 12) relationship between infiltration rate and time for different water heads. 0 50 100 150 200 250 300 0 500 1000 1500 2000 2500 3000 3500 cumulative time, min. c u m u la ti ve i n fi lt ra ti o n , cm field infiltration laboratory infiltration h=30cmh=20cm h=10cm figure (13): relationship between cumulative infiltration and time in field and laboratory tests. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٢٣ 0 2 4 6 8 10 12 14 16 18 20 0 500 1000 1500 2000 2500 cumulative time, min. l a b o ra to ry /f ie ld i n fi lt ra ti o n r a ti o , % calculated predicted figure (14): relationship between cumulative time and in field and laboratory tests. article al-qadisiyah journal for engineering sciences 15 (2022) 224–228 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: taghreedkhuzan@gmail.com(taghreed shakir khuzan) https://doi.org/10.30772/qjes.v15i4.856 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. analysis of rural road traffic crashes in al-diwaniyah province using artificial neural network taghreed s. khuzana and mohammed a. al-jumailib a roads and transport department, college of engineering, university of al-qadisiyah, iraq b civel department, college of engineering, university of kufa, iraq a r t i c l e i n f o article history: received 04 august 2022 received in revised form 25 october 2022 accepted 30 november 2022 keywords: keywords: traffic crash ann rural roads cso a b s t r a c t traffic crash commonly referred to as a car crashes with another vehicle or other objects, such as pedestrians, animals, road barriers, or other immovable structures like a utility pole or wall. this can result in injuries, fatalities, vehicle and road damage. in latest years, the number of traffic crashes has increased in iraq, particularly on rural roads. because of the severity of the rural road crash problem in iraq, it has become critical to investigate and understand the causes of rural road traffic crashes. rural road traffic crashes in al-diwaniyah province haven't been highlighted since 2003. according to the planning ministry's yearly statistical report, iraq (2020) the number of crashes recorded in iraq is 8186, 587 of them are in al-diwaniyah governorate. the percentage of traffic crashes in 2020 inside the city was 47.01% and outside it was 52.99%. the goal of this research is to analyze traffic crash data to identify the crucial factors that impact the occurrence of vehicle crashes in al-diwaniyah province. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction due to the serious economic and social effects that traffic crashes have, traffic safety has recently attracted a lot of attention on a global scale. in addition, traffic crashes cause a large percentage of disability and human losses for young groups, and thus reduce the proportion of labor force. adding to the monetary and emotional costs associated with traffic crashes, it is a fact that many people are killed or spend long periods of time in hospitals as a result of traffic crashes every year. after 2003, the amount of vehicles in iraqi cities increased, as did the number of traffic crashes. there was a sharp increase in the total number of automobiles in iraq after 2003, which has been linked to the economy's recovery after the economic blockade was lifted. traffic crashes in iraq are very dangerous, comparable to terrorist operations, and pose a great threat to the lives of the iraqi people. it has been one of the issues that depletes material resources, causes social problems, and results in the loss of human resources, which are considered to be the most important component of society. also, the individuals involved, their families, and their relatives all suffer negative psychological effects as a result of traffic crashes. those who have been directly involved in traffic crashes face serious health consequences. crashes in traffic systems cause long-term or permanent harm. changes in an individual's quality of life, as well as changes in social, family, and professional lives following a traffic crash, including changes in views toward life, are all social consequences of crashes [1]. http://qu.edu.iq/ mailto:taghreedkhuzan@gmail.com(taghreed https://doi.org/10.30772/qjes.v15i4.856 https://doi.org/10.30772/qjes.v15i4.856 http://creativecommons.org/licenses/by/4.0/ taghreed s. khuzan and mohammed a. al-jumaili /al-qadisiyah journal for engineering sciences 15 (2022) 224–228 225 road geometry (such as infrastructure quality and curvature), traffic conditions (such as speed and the traffic flow), and lighting conditions (such as night and day driving) can all affect traffic safety, as well as driver behavior [2]–[6]. the human errors is the main cause of traffic crashes in the city of baghdad, according to the study of al-tamimi [7]. by investigating roadway elements, particularly roadway geometric design, human aspects can be controlled and predicted indirectly [8]. also mechanical breakdown of a vehicle, such as tires, brakes and steering failure, lead to a slight percentage of crashes [9]. the condition and performance of the roadway, including the road surface, shoulders, crossing points and traffic control system, can influence a collision [10]. according to garber having more lanes, heavier traffic volume, exceeding the posted speed limit, having a low lane width, and having a low shoulder width all increase the probability of a crash [11]. the installation of median barriers in the roads has a number of drawbacks, including a high cost and an increase in the number of traffic crashes reported as a result of a lack of recovery area. more collisions raise maintenance expenses and raise the possibility that maintenance staff will be exposed to traffic. additionally constrained is the ability of maintenance and emergency vehicles to cross the median [12]. it is widely expected that deterioration of the road surface will lead to higher in crash rates. because the state of the pavement is one of the road's environmental elements that influence both human and vehicle factors at the same time, it is regarded as a critical factor in h ighway safety. as a result, one of the main goals of pavement management systems is to improve highway safety by ensuring that pavements are well maintained. according to the findings of lee et al., a deteriorating pavement reduces the severity of one-vehicle crashes on low-speed roadways but rises the severity of single-vehicle collisions on high-speed roadways in poor pavement condition. otherwise, it worsens the severity of multiple-vehicle collisions on all roadways [13]. al-obaedi conducted a study to evaluation traffic crash rates in aldiwaniyah governorate. according to the study findings, traffic crashes cause 33 deaths per 100,000 people in the city. and this is a significantly higher than the average global death rate, which is 18 deaths for every 100,000 people. additionally, research has shown that 50% of traffic collisions are caused by driver errors, while vehicle malfunctions account for about 24 percent. in addition, the findings revealed that approximately 21% of crashes are not reported to the local traffic [1]. . 2. study area al-diwaniyah province is one of the provinces of the middle euphrates, it is about 180 km from baghdad. through which one of the branches of the euphrates river passes, known as shatt al-diwaniyah. the latitude of diwaniyah city is 31o57'50.91'' n and the longitude 44o 54'23.94'' e. elevation of diwaniyah city is 50 meters above sea level. as f or the city's administrative boundaries, it is bordered to the north by the provinces of babil and wasit, to the east by the provinces of dhi qar and wasit, to the south by the muthanna province, and to the west by the najaf province. according to the report of the diwaniyah investment commission, the area of the governorate is about 8153 km2, and thus it constitutes about (1.9%) of the total area of the country, and about (8.1%) of the total area of the provinces of the middle euphrates region. out of the total population of iraq, which exceeds 41 million for the year 2021, according to the estimates of ministry of planning cso reports, the population of diwaniyah province is estimated at 1,325,031 distributed over 57% live in urban and 43% in rural area. figure 1 shows the administrative boundaries of the city. figure1. diwaniyah province boundaries 3. time limits the study's time frame was determined by the number of road traffic crashes recorded between 2016 and 2021 by th e diwaniyah traffic directorate. 4. data collection data on traffic crashes is collected by responsible agencies and authorities in most developed countries according to well-defined standards and procedures. in these countries crash data comes from a variety of sources including insurance, police reports and hospital records. in iraq, there are only two sources of traffic crash data. first, crash report forms, which are filled out by the traffic police officer. second, by preparing a questionnaire and distributing it to a certain number of people who are often participants in a specific traffic crash, asking them a series of questions, then collecting and analyzing the data. questionnaires are usually prepared by researchers, and the questions of the questionnaire depend on the data that the researcher needs in his study. government sources, are more comprehensive. also, the process of collecting traffic crash data is a difficult process in iraq, because of the routine procedures in the country, as well as because of the ministry of interior’s reservation on this data, as it is data that contains some drivers’ details and is used for the purposes of legal cases. 4.1. collecting crash reports from diwaniyah traffic directorate it was difficult for this study to obtain data from the traffic crash records from the diwaniyah traffic directorate because of the security and routine procedures in iraq, as obtaining the data required approval from the ministry of interior in baghdad. the fact that this data, according to their claim, contains personal information of the participants in the crash and is only released for the purposes of legal cases. after submitting official requests to the general traffic directorate in the ministry of interior in baghdad, and after a period of more than three months and many reviews 226 taghreed s. khuzan and mohammed a. al-jumaili /al-qadisiyah journal for engineering sciences 15 (2022) 224–228 to the ministry of interior in baghdad, approval was obtained to provide this study with the necessary data. crash reports are the data obtained from the traffic directorate. these reports contain the details of the crash, which include the type of crash, the type of road, the cause of the crash, the number of vehicles involved in the crash, the number of deaths and injuries, and some other details. this traffic data is more detailed for crashes than the data of the cso. 5. artificial neural networks (ann) an artificial neural network is a model of information processing that mimics how biological nerve systems, like the brain, process information. the impressive quality of artificial neural network models is that they can predict and display desired results even with small amounts of data [15]. a.o. kurban looked into artificial neural networks, which have non-linear mapping algorithms and a structure that is based in part on concepts found in biological nervous systems. typical real neurons have branching dendritic trees that gather signals from numerous other neurons in a small space; and a lengthy branching axon that contacts the dendritic trees from several additional neurons to distribute the response. the response of each neuron is fundamentally a non linear function of the its input and is strongly impacted by the connections among those inputs. figure 2 shows the multilayer feedforward network. figure2. multilayer feedforward network [16] typically, an ann is made up of a lot of simple processors linked by connection weights. the data that is available locally at each node, whether it is stored internally or comes in through weighted connections, is the only factor affecting each node's output. each nodes send its output to a number of other nodes while also receiving input from a large number of other nodes. by changing the connection topology and connecting weight values, a network is specialized to perform various functions. connecting units with the right weights allows for the implementation of complex functions [16]. 6. statistical analysis using ann after the process of filtering the data obtained from the diwaniyah traffic directorate and after excluding the unclear and incomplete copies, the number of copies available was 200 copies of the crash report. spss version 28 and a multilayer feedforward network with one hidden layer was used to unveiled some important factors that might contribute to a more severe crash. as an introduction to dealing with neural networks, the data must be filtered and not be excessive in including a large number of independent variables because this negatively affects the neural network [17]. 6.1. ann inputs and outputs selecting the input variables that have the biggest effects on model performance is a crucial stage in creating ann models. a good subset of input variables can greatly enhance model performance [18]. the following kinds of data changes have been made: removal of invariant columns, removal of columns with a lot of variety, removal of redundant columns, elimination of useless data, and classification of some columns. after preprocessing the traffic crashes d ata, the 16 different attributes were reduced to 8 attributes. the inputs were season, day of week, number of lanes, direction, crash type, number of vehicles involved, vehicle type, collision with, contributing factor, causes, road condition, road type, weather and vehicle manufacture. while the output was crash severity. table 1. class labels selected 8 attributes with their data type no. attribute name data type 1 season nominal 2 3 4 5 6 7 8 9 day of week time crash type collision with contributing factor causes vehicle manufacture nominal nominal nominal nominal nominal nominal nominal eight nodes are chosen in this study as the number of nodes in each layer, which is equal to the number of the input layer's nodes. available data is divided into two sets: training and testing. the training set is used to modify the neural network's connection weights, and the testing set is used to evaluate the network's performance. in the current study, the optimal division was chosen using a trial-and-error procedure. the software's default and non-default parameters were used to create a number of networks with various divisions, and the results showed that 66.5% of the data were used for training and 33.5% for testing. figure 3 illustrated the distribution of the data. taghreed s. khuzan and mohammed a. al-jumaili /al-qadisiyah journal for engineering sciences 15 (2022) 224–228 227 figure 3. classification of data 6.2. structure and operation of ann a typical ann structure comprises of a few artificial neurons, or nodes, and the links that connect them. there is a weight parameter associated to each bond. every processing element in a particular layer is connected to many other processing units via weighted connections, either entirely or in part. the scalar weights control how strongly linked neurons are connected to each other. when a weight is zero, there is no connection between any two neurons, and when a weight is negative, there is a prohibitive association[19]. one layer of input neurons, one or maybe more layers of hidden neurons, and one layer of output neurons typically make up ann neural networks; however, the subsequent layers are completely connected, as illustrated in figure 4. figure 4. typical structure and operation of ann [19] 6.3. ann prediction accuracy many trainings were performed on the artificial neural network to achieve the highest accuracy and lowest error rate. and that is by controlling the percentages of the training and testing samples, the change of weights, the hidden layers and the number of nodes of the hidden layers. the total sample size of 200 was used to make the artificial neural network. the sample was divided into a training sample and a testing sample. 66.5% was used as a training sample and 33.5% as a test sample, which gave the highest accuracy rate. figure 1 shows the details of the artificial neural network used. the correctness rate of the model was 98.5% for the training sample and 98.5% for the testing sample as well. this means that the model was able to correctly classify most of the data, except for 1.5%. figure 3 shows the process of classifying data from spss. the model classified crashes with pdo with an accuracy of 90%, injury crashes with 98.9%, and fatal crashes with 100%. this is for the training sample. these findings show that the prediction accuracy for fatal crashes is highest, followed by injury crashes and pdo crashes, in that order. the original percentages of crashes were as follows: crashes of property damage were 8.5%, crashes of injury 59.6%, and crashes of death 32%. as for the testing sample, it was classified by 85.7%, 100%, and 100%, respectively, with regard to crashes of property damage, injury, and fatality. the prediction efficiency, however, cannot be fully described by accuracy alone, hence additional methods of assessing the predictive models are required. the total ability of a test to discriminate is measured by the area under the curve (auc). an ideal test has an auc of 1.00, while a completely random test has an auc of 0.5 . for the current study, the created models were further assessed using auc curves. the percentage of the area under the curve for each category of the dependent variable was as follows, as shown in figure 5. figure 5. area under the curve the aucs were all noticeably higher than 0.5 in each example. these findings show that all models performed well in predicting new cases. 7. results the importance analysis of the model is illustrated in figure 6 and indicates the cause of the crash has the greatest impact on the severity of the crash. followed by the season in which the crash occurred, and then the time of the crash. where the importance of these variables was 0.313, 0.181 and 0.158, respectively. figure 6. independent variable importance analysis the importance analysis results also indicate that the day of the crash, the object to which the vehicle hits, the vehicle brand, the type of crash, and the factors contributing to the crash have less influence on the expected result, having values for relative importance of 0.104, 0.083, 0.059, 0.052 and 0.05 respectively. 8. conclusions 1. artificial neural networks can be used to analyze traffic crash severity . it can analyze traffic crashes with high accuracy and does not require a very large sample size. 2. the accuracy rate of the model was 98.5% for the training sample and 98.5% for the testing sample. 3. the model classified crashes with pdo with an accuracy of 90%, injury crashes with 98.9%, and fatal crashes with 100%. this is 228 taghreed s. khuzan and mohammed a. al-jumaili /al-qadisiyah journal for engineering sciences 15 (2022) 224–228 for the training sample. as for the testing sample, it was classified by 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[19] m. a. shahin, m. b. jaksa, and h. r. maier, “state of the art of artificial n eural networks in xengineering,” electron. j. geotech. eng., vol. 13, no. i, pp. 1 –25, 2008. ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ١ دراسة تصميم وأداء محرك بارد وعديم التلوث باستخدام النتروجين السائل كمائع شغل حيدر شاكر عبد اهللا. د جامعة القادسية–كلية الهندسة قسم الهندسة الميكانيكية ةالخالص openة دورة رانكن المفتوحأساسكمائع شغل لمحرك يعمل على ln2تم استخدام النتروجين السائل .rankine cycle حرارة خالل شوط ان هذا المحرك تم تصميمه نظرياً بحيث يحقق اكبر عملية انتقال يوجد فيه أي هذا المحرك الإن، حيث مبادالت حرارية هوائيةباستخدام expansion stroke التمدد فان , لة خالل شوط التمدد كبيرة كانت كمية الحرارة الداخإذا .احتراق بل تمدد لضغط النتروجين السائل فقط هذا المحرك يعوض عن استخدام المحركات الكهربائية من ناحية القدرة الخارجة وكلفة التشغيل في حالة العديد من الطرق الالزمة إلى افةباإلض .كل هذه التحديات الهندسية تم دراستها في هذا البحث . بالجملةاإلنتاج . isothermal expansionي للحصول على التمدد االيزوثيرم .تمدد، آيزوثيرمي، مائع الشغلمحرك، مركبات، : ةكلمات رئيسي a study for design and performance of a cool and zero emission engine using liquid nitrogen as a working fluid dr. hayder shakir abdulla al-qadisiyia university-college of engineering mechanical engineering department liquid nitrogen ln2 is used as a working fluid for an engine using an open rankine cycle. ambient heat exchangers are used to open power the engine that is configured to maximize heat transfer during the expansion stroke, where in this engine no combustion will occur, but only expansion to ln2. if sufficient heat input during the expansion process can be realized, then this engine would provide greater automotive ranges and lower operating costs than those of electric vehicles currently being considered for mass production. this engineering challenges has been evaluated and several means of achieving isothermal expansion are discussed. ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٢ nomenclatureالرموز المستخدمة ap : 2,المساحة السطحية لرأس المكبسm ac : 2 ,المساحة الداخلية لحجم الخلوصm :aw 2 , المساحة الداخلية لالسطوانةm ah :س,ااس راحة سم 2mلمكب : cpالحرارة النوعية,j/kg.k d : قطر االسطوانة,m f: البعدي,معامل االحتكاك للغاز h : المحتوى الحراريenthalpy, j/kg hx : معامل انتقال الحرارة ,kmw ./ 2 k: الموصلة الحراريةkmw ./ m :معدل تدفق الكتلة ,kg/s n,m :3( للمعادلةأسس( nu:نسلت عدد , k hd, البعدي n : السرعة الدورانية ,rpm p : الضغط ,n/m2 pr : عدد يرانتدل k µc p ,البعدي q: انتقال الحرارة ,w r : البعدي, نصف قطر عمود المرفق إلىنسبة طول عمود الربط re :عدد رينولدز, µ dρu p s : طول الشوط ,m , stroke st : عدد ستانتن pcρ p x u h البعدي, t: درجة الحرارة ,k tr :سمك حلقة المكبس ,m up : سرعة المكبس ,m/s v : الحجم ,m3 vc : حجم الخلوص ,m 3 vh : حجم الرأس ,m 3 ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٣ wf :شغل االحتكاك ,j w : شغل الدوررة ,j greek الرموز اليونانية η :الدورة ةفاءك θ : زاوية عمود المرفقgrank angle , degree γ : نسبة الحرارة النوعية , v p c c البعدي , µ : اللزوجة الحركية , sm kg . δs : الشوط التفاضلي جزء ,m fδw : جزء الشغل االحتكاكي التفاضلي ,j subscriptsالرموز الدليلية السفلية i: الحقن ,injection e : العادم ,exhaust w : الجدار ,wall h : عالي, high l : واطىءlow introductionالمقدمة الجـو مـن ةباالسـتفاد هـي ln2ام النتـروجين الـسائل ان الفكرة األساسية في استخد atmosphere ص السائل ليتم اسـتخدامه فـي دورة القـدرة م حراري ليبخر ويح ر كمصد على عكس المحركات الحرارية المعروفة والتي تستخدم مصدر طاقة بدرجة حرارة الحرارية في كـال الحـالتين ان .heat sinkاعلى من درجة حرارة الجو باستخدام الجو كوسط بارد :كفاءة الدورة هي h l h t t 1 q w −==η (1) k تعمل بين درجة حرارة يالحرارية الت للماكنة % 74ان القيمة المثالية للكفاءة الحرارية هي th=300 77رةودرجة حراk tl= 2حيث ان الـشغل يـساويln-kj/kg 769=w والـذي ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٤ وبهذا نحتـاج kj/kg 300-180حامض والتي تعطي – بطاريات رصاص عمقارنة م يعتبر كبير .باستخدام المحركات الكهربائية من الشغل الناتج لنقل نفس الحمولة % 40لـــ ln2منظومة تستخدم النتـروجين الـسائل قدموا ) hencey) 1972 و boeseالباحثان والهواء الجوي لتدوير محرك مربوط بمولد كهربائي حيـث ان الهـواء يـستخدم لتـسخين .النتروجين brayton cycleاستخدموا دورة يرايتون ) scheider) 1974 و manningالباحثان حيث تم استخدام العديد , ln2باستخدام النتروجين السائل للحصول على الشغل من المحرك كما . وسطية متبوعة بمرحلة غاز اخيرة reheatمن عمليات التمدد مع عمليات اعادة تسخين والهواء الساخن خالل حجم معين بشكل متناوب n2انهم استخدموا اله تمرر النتروجين البارد د وتـسترخي حيث ان هذا الحجم يحتوي العديد من اسالك الشد المربوط بالمكبس حيث تش , .خالل دورة حرارية الستغالل اخر كمية من الطاقة في مائع الشغل بكفاءة عالية وفصل الهواء في الدورة الحراريةliquefactionاقترح اسالة ) oxley ) 1980الباحث تخدمةا تـراق يستخدم لزيادة كفاءة االح 2oحيث ان االوكسجين في محركات الباصات لمس يا االخيرة في ماكنة سـترلنج نوالغازات المسالة يمكن غليانها بالتدوير حول درجة الحرارة الد striling engine باستخدام الهليوم heكمائع شغل . في منظومة التـوربين الغـازي ln2 استخدم النتروجين السائل boese(1981) الباحث turbine gas , ام مبادل حراري يكون المائع الساخن فيـه حيث ان الحرارة تضاف باستخد المـستقبل كمـا ان منظومـة .التكييف في مقطورة المـسافرين هو الهواء القادم من منظومة receiver ها قد تم .في هذا البحثافتراض صمموا منظومة لزيادة سرعة المحركات التي تـستخدم )1982( وزمالئه latterالباحث وذلك باالستفادة من حرارة الجو )الخ....lpgالوقود المسال , بنزين ,ديزل (الوقود التقليدي الحـرارة القادمـة مـن غرفـة إلى باإلضافة ln2 بعمليات اعادة تسخين النتروجين السائل االحتراق في هذه الطريقة هو ان الهواء المسال يستخدم كمائع شغل اوالً في دورة .تراق حاال ان عملية الدمج هذه تمكـن .قليدي الى محرك االحتراق الداخلي رانكن قبل حقنه مع الوقود الت كما تم .من كونه يستخدم كل مصدر وقود على حده % 50المحرك من قطع مسافة اكثر بــ systemمناقشة االستفادة من حرارة االحتكاك القادمـة مـن المحـرك ومنظومـة الكـبح braking. adiabatic اعاله كانت عمليات التمدد كظيمة ةمن المالحظ ان في جميع البحوث السابق expansion االيزوثيرميـه مع اعادة تسخين ولـم تـستخدم عمليـة التمـددisothermal expansion كما في هذا البحثه مع ماكنة بارد . ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٥ system 2ln منظومة النتروجين السائل النتروجين السائل . ث يمثل رسم توضيحي للمنظومة المستخدمة في هذا البح )1(الشكل ln2 خاصة تضغط السائل الى بمضخهضغطهمخزون في اسطوانة مخلخلة الضغط ثم يتم ثم يمر بمبادل حراري يـسمح المنظومة الى supercritical pressureضغط حرج فائق بعـدها يمـر . frostلمائع الشغل للوصول الى درجة حرارة الجو بدون حصول الـصقيع والذي يقلل من تذبذبات الضغط في المنظومة حـسب receiver بالمستقبل ln2النتروجين cylinder-piston مكبس –كذلك توجد صمامات في منظومة االسطوانة . متطلبات القدرة ,.williams et. el) و )n2) williams, 1997لتـتحكم بـدخول وخـروج النتـروجين مكبس ليـتم ابقائهـا بدرجـة –االسطوانة يتم تدويره خالل منظومة السائل المسخن .(1997 كما ان السائل المسخن يمر بمبادل حراري ثاني ليوصل .حرارة قريبة من درجة حرارة الجو منظومـة صـندوق بعدها يتم الحصول على الحركة مـن خـالل . الى المحرك حرارة الجو exhaust n2 بما ان النتروجين الخـارج . ثم الى العجالت gear box التروس المعروفة استخدامه لتسخين النتروجين السائل اولياً فـي مبـادل ملذا يت , قريب من درجة حرارة الجو .حراري ليقلل التماس بين السائل البارد والجو مكبس–التحليل النظري لمنظومة االسطوانة piston system -analytical analysis for cylinder لمحرك الترددي سيتم شـرحه ليـتم التعـرف علـى مختلـف التحليل الثرموديناميكي ل النمـوذج . على استهالك الوقود وتأثيرها ln2 الخاصة بمحرك النتروجين السائل المتغيرات تـأثيرات إليجـاد للمبادل الحراري في هذا التحليل يستخدم model theoretical النظري , boreالقطـر ,ناتج من المكـبس للمنظومة على الشغل ال الضغط ودرجة الحرارة الداخلين . rpm)west, 1996 (caton and باالظافة الى سرعة المحرك الدورانية strokeالشوط إشـكال سيتم تعميمه ليتم تفحص مدى كبير من simulation procedure المحاكاة أسلوب معدل تدفق الـسائل المـسخن وابعـاد .piston-cylinder head اسطوانة المكبسرأس .جادها لمختلف التغييرات باإلبعادادل الحراري سيتم إيالمب المعتمد على الزمن على حجم الـتحكم single zoneيتم تطبيق تحليل المنطقة الواحدة على فرض ان محتويات االسطوانة ثابتة الخواص وخاضـعة لمعادلـة )2(بالشكل الموضح فرض ان درجة حرارة الجدران الداخليـة كذلك يتم . للغاز المثالي state equationالحالة p-v diagram. حجـم –لالسطوانة ثابتة اما الشغل الناتج سيتم ايجاده من مخطط الـضغط ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٦ معادلة . في حجم التحكم يتم ايجادها من قانون حفظ الطاقة n2الحالة اللحظية لغاز النتروجين :ها كمايلي لمحتويات االسطوانة يمكن التعبير عنenergy equationالطاقة ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ −+ θ−γ γ − θ −γ = θ e e i i h dt dm h dt dm d dv p 1d dq v )1( d dp (2) -slider بان حجم االسطوانة يمكن الحصول علية من معادالت نظرية المكـائن الخاصـة crank (hannah and stephens, 1985) كمايلي: ))sinr(rcos1(8 sd vvv 22 2 ch θ−−+θ− π ++= (3) cylinder heat -pistonمكـبس –انتقال الحرارة في منظومـة اسـطوانة transfer ومعدل سرعة الدوران للمحرك sوالشوط , d العالقة بين قطر االسطوانة إيجادلغرض خـالل عمليـة التمـدد n2يجب تخمين معدل انتقـال الحـرارة للنتـروجين , nالترددي expansion. البحوث السابقة تستخدم العالقات التجريبيـة اغلبيةemperical equations فـي . radiation والذي يتـاثر بانتقـال الحـرارة باالشـعاع معامل انتقال الحرارة إليجاد الدراسات الخاصة بايجاد الخسائر الحرارية من المحرك بدون احتراق تتم من خـالل انـشاء في هذا البحث سيتم افتراض ان األسبابلهذه . يبية عالقة تجر إيجادنموذج صغير للمحرك ثم turbulent heatingالسطوانة شبيه للتـسخين االضـظرابي انتقال الحرارة خالل جدران ا :holman,1997)(يلي للغاز في انبوب كما nm ddnu prre~ where coolingfor8.0 heatingfor3.0 flowturbulentfor8.0 = = = m m m (4) في المدى t على درجة الحرارة n2للنتروجين µ واللزوجة k الموصليه الحرارية يةاعتماد )200-300k( يتم ايجادها من خالل تفحص جداول البيانات الثرموديناميكية والتي تعطـي :مايلي 0.760.85 t~,t~k µ (5) مما يعطي عالقة لمعامل upعلى فرض ان سرعة الغازات تتناسب مع معدل سرعة المكبس كمايلي hxانتقال الحرارة 594.08.0 p 8.02.0 x tupd )1129.0(h = (6) ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٧ لمعامالت least squareحيث ان الثوابت في المعادلة اعاله تم ايجادها باستخدام طريقة ان تاثيرات . )prasad and samira, 1970(ية الموجودة في المصدر لمانتقال الحرارة الع هذا . up هي اصالً مضمنه بعالقة سرعة المكبسn وسرعة الدوران sشوط المكبس ثر االداء مع مختلف المتغييرات أبل يمكننا من معرفة ت, التقريب اليخمن انتقال الحرارة فقط .اعاله تطبق على hxانتقال الحرارة الداخلة الى الغاز يتم ايجادها بفرض ان عالقة ان معدل لذلك فان انتقال . رة ثابتة خالل الدوtwالسطوح في شوط التمدد وان درجة حرارة الجدار :الحرارة يعبر عنه كمايلي )tt(ah dt dq wwx −= (7) : عند أي درجة حرارة للكرنك هي aw المساحة السطحية الكلية للجدار إن θ)sin-r-r+cosθ-2(1 πds +a+a+a=a 22chpw (8) frictionsring–piston خسائر احتكاك المكبس مع الحلقات سيتم حسابه ألنه يتأثر بشكل كبير مـع ringsان خسائر الشغل نتيجة الحتكاك الحلقات يمكن تخيل ان ضغط الغاز يحاول ان يمدد . ratio aspect نسبة طول الى قطر االسطوانة باتجاه جدران االسطوانه لذا يجب استخدام قيمة ثابتة لمعامل االحتكـاك االنزالقـي الحلقات علـى fδwلذلك فان الشغل التفاضلي لالحتكـاك . taylor, 1993 (rµ(بدون وجود مائع :حلقات الضغط يمكن التعبير عنه كمايلي δs dt pπµ=δw rrf (9) على دورة كاملة للمحرك لحساب خسائر الشغل على االحتكاك والذي تكامله هذا التعبير يتم ى جدران االسطوانة وحلقات المكبستت الشهذه الطاقة ت. يطرح من الشغل الناتج من الدورة .dt سيهمل خالل هذه اللحظة ةتأثيرها على انتقال الحرارأما warmant systemمنظومة المسخن –االثيلـين المسخن هو مزيج غير قابل لالنجماد من الماء و ان المائع المستخدم في دورة فـي اغلبيـة تستخدم هذه المنظومة مشتت حرارة عادي كما ethylene glycol.-ايكولالگ ومضخة ماء النها متوفره بكثرة على فـرض ان كفـاءة autombile radiatorالسيارات أي فـرق فـي انتقال الحرارة الى الجو يحدث عند نأ % .90هي مضخة الماء الميكانيكية والتي تحتاج الى فـرق كبيـر على خالف اغلبية السيارات درجات الحرارة بين الماء والجو ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٨ اي ان كمية الحرارة الداخلة للدورة تكون اقل مـن الحـرارة المطـرودة .بدرجات الحرارة rejected heat من محركات اغلبية السيارات التي تعمـل بـالوقود المحـروق . fuelburning engine حكمه بمعادلة ان تسخين المائع المسخن من الجو في المبادل الحراري يتم يتم ايجاده من تناضـر f اما معامل االحتكاك ) . )٤(معادلة(الجريان المضطرب خالل انبوب .)(reynold's analogy holman,1997رينولدز 2/3.prst = f/8 (10) عالقة انتقال الحرارة لجريان نة هومل للمائع المسخن حول االسطواحمعامل انتقال الحرارة بال cross-flow) (holman, 1997متقاطع حول اسطوانة 0.30.52 d d pr )re 0.56 + (0.35 =nu (11) هو عالقة انتقال الحرارة cylinder-head سطح االسطوانة معامل انتقال الحرارة علىأما .)flat-plate) holman,1997 صفيحة مستوية على pr re 0.332 =nu 1/31/2dd (12) للمـائع mية موازنة للطاقة الي تغيير بدرجة الحرارة يوجد من خاللـه معـدل الجريـان أ لتجهيز االسطوانة بالفيض الحراري من جدران االسطوانة خالل warmant fluidالمسخن .شوط التمدد analytical procedureأسلوب التحليل . من المرتبة الرابعـة rang-kuttaكتا -باستخدام طريقة رانج ) 2(تكامل المعادلة .١ .للدورة) 1800-0( لزاوية كرنك من p-v diagramحجم –ثم ايجاد مخطط الضغط ضغط ودرجة حرارة الغاز علـى معامـل انتقـال تأثيرات إليجاد) 6(فذ المعادلة تن .٢ .expansion strokeالحرارة خالل شوط التمدد وخسائر المـضخة مباشـرة مـن الكفـاءة ) 9(حساب خسائر االحتكاك من المعادلة .٣ .الميكانيكية لها ثم ايجاد الحجـم بقيمة معينة injection pressureتحديد ضغط الدخول لالسطوانة .٤ .بداية شوط التمدد من المعادلتين قبل initial volumeاالبتدائي ) t t ( ) v v ( p p 1 i 2 2 i i 2 −γ γ γ == (adiabatic) vp vp 22 ii = (isothermal) )vv( اقل من ivاذا كان الحجم االبتدائي hc هـذين يملـئ حينذاك يتم فرض ان الغـاز + .tdc من النقطة الميتة العليا يبدأ expansion strokeالحجمين وان شوط التمدد ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ٩ results and discussionالنتائج والمناقشة nة الدورانيـة والـسرع ) s/d ( الى الشوط قطر االسطوانة نسبةمن المهم دراسة تاثير ان نسبة الشغل االيزوثيرميه . )isothermal work) iw/wعلى نسبة الشغل االيزوثيرميه ـ 1cm لمجموعة محركات لها اسطوانة قطرها مـع 30mpa-1 بالمـدى نتعمل بضغط حق mpa11.0pex ضغط خروج خدام حيث تم اسـت )3(بالشكل موضح 290k ودرجة حرارة= مـن المالحـظ مـن .كمتغيير) s/d( ونسبة قطر االسطوانة الى الشوط n سرعة المحرك تكون لدينا اشواط طويلة وسرعة محرك قليلة فان ذلك يزيد مـن انتقـال عندما ,) 3(الشكل .expansion processالحرارة خالل عملية التمدد حيث ان هذه الحالة توضـح , اً ضاي) 3(في الشكل d/s =1/4 و cm 10 =dالة توجد ح ان الحسابات اعـاله تبـين . bore قطر االسطوانة قلة الشغل الناتج من الدورة نتيجة لزيادة cycleقطر صغير وسرعة قليلة هـي مـن شـروط الحـصول علـى دورة ايزوثيرميـة isothermal. ان الحسابات اعاله لمحرك ذو اسطوانة واحدة لذلك يمكن مـضاعفة الـشغل .الناتج بزيادة عدد االسطوانات حسب القدرة الالزمة كما في محركات السيارات لمحرك قطـر مكبـسة θ عمود المرفق من زاوية داله ك درجة الحرارة والشغل النوعي 1cm وطول شوطه s=10cm يعمل بسرعة n=1000rpm وبظروف ايزوثيرمية وكظيمة adiabatic تمثـل 130 و 120 ان الدرجات )4(نالحظ من الشكل . )40(بالشكل موضح تبـدا بالزيـادة مـن من المالحظ ان خسائر الشغل.stroke expansionبداية عملية التمدد تمدد يتم الحصول على اكبر كميـة خالل هذه المرحلة من ال . في الحالة الكظيمة 600 الزاوية من الشغل الناتج والذي يولد الحاجة الى اكبر كمية مـن الحـرارة الداخلـة لتحقيـق االداء .isothermal performanceااليزوثيرمي ابتدائياً يساوي صفر خالل عملية الحقـن ان الفرق في درجة الحرارة بين الجدار والغاز injection 5(بالشكل يزداد عندما ينجز النظام شغل على المكبس كما موضح في الدورة ثم( بسرعة مع انخفاض الضغط حتـى لـو زادت سـرعة يهبطhxان معامل انتقال الحرارة . يشجع على تـصميم منظومـة اسـطوانة هذا السلوك . وقلة درجة حرارة الغاز pu المكبس والغاز مع زيادة معامل انتقال فرق بين درجة حرارة الجدار مكبس بدورة ايزوثيرمية لها اقل .expansion chamber خالل غرفة التمدد wetted areaالحرارة والمساحة المبتلة لمنحني simulationفان المحاكاة لغرض معرفة الفوائد من زيادة معامل انتقال الحرارة const=h يبدل بحالة adiabaticالتمدد الكظيم x نالحظ الشغل . واليقل خالل شوط التمدد الناتج ودرجة الحرارة خالل النصف االول من شوط التمـدد فـي specific workالنوعي ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ١٠ هذه النتـائج . منحنيات الشغل ودرجة الحرارة تكون قريبة من الحالة المثالية ان). 6(الشكل 60خالل شوط التمدد خالل ار عشرة اضعاف بمقد xhتقابل زيادة . للكرنكاألولى ٠ تحت هذه الظروف مقارنة مع حالة معامل )w/wi=0.85 (ان نسبة الشغل االيزوثيرمي ان الدورة قريبة من شـوط التمـدد وهذا يدل على ) .w/wi=0.65(انتقال الحرارة المتغير يرمي للحصول على الحالة المثاليـة للـشغل أي ان التمدد يجب ان يكون ايزوث ,االيزوثيرمي من خـالل جعـل عمليـة الحقـن xh ممكن زيادة معامل انتقال الحرارة .ودرجة الحرارة ممكن زيـادة المـساحة transfer heatاما لزيادة انتقال الحرارة . مضطربة مع دوامات .finsراس المكبس كوضع زعانف مثالً لالسطحية يمكن مقارنة بعض نتائج األداء للمحرك البارد المصمم في هذا البحث مع محركات شركة حيث ان القدرة الالزمة لتحريك السيارة بسرعة ) honda crx )reynolds,1992هوندا 97 km/hr 7.8.كانت kw القدرة يمكن الحصول عليها من محرك النتـروجين هذه حيث ان 6 وضـغط حقـن rpm850 ة واحدة عنـدما تعمـل بـسرعة السائل باستخدام اسطوان mpa 290ودرجة حرارة حقنk 300 في جو درجة حرارتهk والحرارة الداخلـة للـدورة 22kwاما اكبر كمية حرارة منتقلة بواسطة المائع المـسخن هـي . تقريباً kw 11تساوي )/ (mixture والتـي تبـين ان معـدل جريـان الكتلـة لـه هـو glycolethylenewater − 1.1kg/s 5لهبوط بدرجة حرارة مقدارهk . اما في الظروف التشغيلية خالل السرعة للسيارة نافس أحـسن بطاريـات يوالتي تجعله 2ln-245kg/kgفان المنظومة تحرر طاقة مقدارها . رصاص المستخدمة حالياً–الحامض conclusionsاالستنتاجات تصميم وحساب اداء محرك بارد وعديم التلـوث تم ايجاد واثبات االسلوب الصحيح ل .١ . العادم هو هواء فقطإن حيث في هذا البحث قليلة للمحرك هي من اهم الشروط للحصول على قطر صغير لالسطوانة وسرعة ان .٢ .دورة ايزوثيرمية يتم الحصول بها على اكبر شغل الي قد تم خـالل االيزوثيرمي المث األداءمن % 85اثبتت حسابات انتقال الحرارة ان .٣ .ln2المحرك الترددي الذي يعمل باستخدام النتروجين السائل وبـسرعة 6mpaفي حالة كون المحرك ذو اسطوانتين يعمل بضغط حقن مقـداره .٤ rpm850 15سوف ينتج قدرة مقدارهاkw 190وعـزم مقـدارهn.m. وهـذه تروجين الـسائل لتر من الن200 باستخدام km 140انات تمكن السيارة من المسيريالب .بدون ملوثات للبيئة ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ١١ referencesالمصادر 1. boese , h.l., and hencey jr.,t.r.1972,"non–pollution motors including cryogenic fluid as the motive means, " patent no.3,681,609 aug. 1. 2. boese , h.l., 1981,"crygenic powered vehicle," patent no.4, 294, 323, oct 13. hannah, j. and stephens, r. c., 1985,"mechanics of machines: elementary theory and examples", 4th ed., edward arnold. 3. holman , j.p.,1997, "heat transfer "7th ed., mc grew–hill pub. 4. latter , a.l., dooley, j.l., and hammond, r.p., 1982,”engine system using liquid air and combustible fuel,” patent no.4, 359, 118, nov. 16. 5. manning , l.,and schneider ,r.n. 1974, "nitrogen vapor engine,” patent no. 3,786,631 jan . 22. 6. oxley, a.j., 1980, “methods and means for storing energy," patent no.4, 227, 374, oct. 14. 7. parsad , r. and samira, n.k., 1970, "investigation of heat transfer in piston with and without ceramic insulation on crown face", ie (i) ,j.-ch,vol.70, june. 8. reynolds , k., 1992, "ac propulsion crx harbinger of things to come," road and track, oct. 9. taylor, c. m., 1993, “engine tribology,” elassvier science pub. 10. west ,c.w. , lee , l.e., and norris, a.o.1978, "vehicle utilizing cryogen fuel,” patent no. 4,106,581,aug . 15 . را n2وجلخ ln2 واءهـ جوي طوانه -ا مكبسس مـضخة المائع المسخن مـضخة ln2 مبادل حراري مبادل حراري مبادل حراري تقبل ا لمس كل(1): ا .2lnتوضيحي لمحرك النتروجين السائل رسملش ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ١٢ inn 2 out n2 .تحليل عملية التمددلالمستخدم c.vحجم التحكم ): 2(الشكل كل(3): ا زوثيرمية التمدد على نسبة الشغل االيتأثير حجم وسرعة المحرك لش .لمعدالت انتقال حراره محدده ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ١٣ عمود المرفقالشغل اللحظي الناتج و درجة حرارة الغاز كداله من زاوية ): 4(الشكل ).10cm وطول الشوط 1cm=قطر المكبس(لعملية التمدد بين الغاز والجدار كداله من الحرارةات جمعامل انتقال الحراره وفرق در): 5(الشكل .عمود المرفقزاوية ٢٠٠٨ ١ العدد ١مجلة القادسية للعلوم الهندسية المجلد ١٤ لمرفق لعملية الشغل اللحظي الناتج ودرجة حرارة الغاز كدالة من زاوية عمود ا ):6(الشكل ).10cm= وطول الشوط 1cm= قطر المكبس (.hx= constالتمدد عندما يكون article al-qadisiyah journal for engineering sciences 15 (2022) 122–126 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: rainaali175@gmail.com (rania al-mrumudhi) https://doi.org/10.30772/qjes.v15i2.822 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. characteristics of on-street parking in aldiwaniyah urban street rania a. al-mrumudhi* and jalal t. al-obaedi roads and transport department, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 29 may 2022 received in revised form 28 june 2022 accepted 18 july 2022 keywords: parking gis cbd parking index parking turnover a b s t r a c t by creating enough parking places, cities may be able to lessen congestion and traffic disruption. thus, the primary issue that frequently arises in urban areas is on-street parking. in aldiwaniyah city's urban streets, on-street parking is a common occurrence. in order to analyze on-street parking characteristics, this study has concentrated on three congested sites: al-orzady street, al saray street, and almusawreen stree. thus; field data were collected using in -out method. the characteristics and kind of parking were looked into. according to the activities at the three sites, it was mostly discovered that the peak time is in the afternoon between 3:10 pm and 4:40 pm. the results of the data analysis show that st3 has a high parking turnover of 1.348 and st1 has a low turnover of 0.67. it was also found through the questionnaire paper that the majority of the vehicles parked on the street are for the purpose of shopping. finally, the results indicate that weekdays in the research area are a typical time for illegally parking. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction at the present time, there are many factors that encourage an increase in the demand for transportation, and consequently the number of vehicles increases, and with this increase, the demand for parking lots increases [1]. increasing the number of cars that visit a particular location, it is required to provide parking for vehicles in that area[2]. because of the rapid industrial development that the world is witnessing today, it has led to economic growth and a high level of income for the population. therefore, we notice an increase in the number of privately owned vehicles [3].the large number of vehicles in urban areas has increased the demand for parking spaces [4]. most people prefer to do many activities at the same time and in one area, so the government and stakeholders must have the ability to provide various public utilities [5]. in the most city center, there is competition over the use of space between different urban activities. the authorities must consult and control for the purpose of giving the appropriate use of each place [6]. there have been many developments in the past decades in order to improve roads and meet parking requirements, the situation is constantly changing, which requires a new approach [7]. most countries suffer from traffic problems at the present time due to the increase in vehicle ownership and the unattractiveness of public transportation, as well as limited parking spaces [8].public parking as an urban infrastructure is among the best parts of the urban transportation framework beyond reducing traffic on street corners [9].city centers suffer from constant overcrowding due to their inability to provide sufficient parking spaces as a result of an increase in the number of cars heading to the city center, which represents the commercial and economic part of the city [10].since the number of vehicles has increased in cities, it has become more difficult to obtain parking for vehicles, and because of the slow driving of the driver while looking for a suitable place to park, it causes http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i2.822 https://doi.org/10.30772/qjes.v15i2.822 http://creativecommons.org/licenses/by/4.0/ 123 rania al-mrumudhi and jalal al-obaedi /al-qadisiyah journal for engineering sciences 15 (2022) 122–126 traffic congestion on the street, and this is a serious problem[11]. one of the negative effects on the flow of traffic is the parking of vehicles in the road in order to obtain a place to stop [12]. at the beginning of the twentieth century, a parking system was built in response to the use of storage areas for automobiles [13]. as a result, much of the current research is directed towards determining the role of the various factors that influence parking policies there is a previous study that worked in china to know the characteristics of parking lots in the center of shanghai, and the facilities were analyzed based on parking indicators. it was found that market areas and areas designated for food and drink show a high saturation of parking spaces. therefore, parking improvement policies have been proposed in shanghai city based on the current parking situation in the city (chen et al.,2016). a study was conducted in the city center of najaf in both locations (al-rawan, al-iskan) in order to verify the characteristics of parking on the street. data were collected by manual census, drones, and video camera. the results indicated that the waiting time for most cars in all the two locations (al-iskan, al-rawan) is more than 80% for a period of 30 minutes (al-jameel and muzhar,2020). study was conducted in the city of bat yam to estimate parking patterns in the city, where it relied on a spatially high-resolution display of heterogeneous demand and supply of parking, as it was shown that the time approaches zero if the distance between the place of parking the vehicle and the destination is less than 50 meters and the time reaches 4.5 minutes if the distance is 200 meters [14]. a study was conducted in the city center of hilla, to address the problem of high demand for on-street and off-street parking where he explained that the vehicles parked on the street contribute to traffic accidents and affect safety, so he suggested using some small spaces for the purpose of making parking spaces for vehicles. [15]. several studies of parking spaces were made in nine sectors in delhi, the business district where the peak for parking was 3.25, as well as the peak for bicycles was 6.21, which indicates a significant indirect condition (mahmoud, 2011). there is a previous study in iran in the city of sanandaj in which geographic information systems were used to determine the parking spaces of vehicles, as it was shown that 234,887 m2 or 14.16% of the study area would be suitable for constructing parking spaces [9]. among the factors that affect the choice of a place to park vehicles (the distance that the driver walks from the parking place to the exits of the car park, protecting the vehicle from sunlight, the safe place to park the vehicle, the distance from the entrance to the parking lot to the area where the car is parked) [16]. urban planning often exceeds parking problems and this is a reason for increasing traffic congestion in urban areas, so solutions must be made during planning and design and improve the level of management [17]. the urban planning of the city must take into account the parking spaces [18]. al-diwaniyah city is one of the iraqi cities in which there are many daily commercial activities in general. the majority of the activities in the city are concentrated in the central business area (cbd), — in other words, the economic center of the city, where people must be able to reach the places where we get activities easily. increasing demand for mobility the need to provide many parking spaces to accommodate the number of parked cars increases [19]. aldiwaniyah city suffers from scarcity of parking places in several regions such as alorzady street , al saray street and almuswreen street. [20] found that onstreet parking decreases roadway capacity in two ways. for begin, it minimizes the width of the highways by limiting the traffic flow. second, excessive parking of vehicles contributes to congestion in urban areas. these two parking places on the street cause a reduction in road capacity city streets. this study's aim is to evaluate on-street parking behavior in metropolitan streets like, al-orzady street, al saray street, and almusawiran street in aldiwaniyah city, because there are few or no studies that deal with onstreet parking in aldiwaniyah city or in iraq in general. the aim of this study may be achieved by gathering information and comprehending the quantity of parked cars on both sides of the street as well as the properties of street. 1.1 parking characteristics in the initial stage of the study, it is required to determine the number of parking spots and to take sufficient and relevant information for the goal of deriving different characteristics linked to on street parking, which are called parking stats or characteristics. in generally, the following criteria are utilized for car parks [21]: 1. parking volume: the total number of cars parked at one time is known as the parking volume. the recurrence of vehicles is not taken into account. it is tracked how many vehicles actually enter the region. 2. parking accumulation: the quantity of parked cars in a studied area at any specified instant. the fluctuation in parking accumulation throughout the day can be shown by plotting this data as a parking accumulation vs. time curve. 3. parking load (space-hour): the area under the accumulation curve is provided by the parking load. it can also be calculated by merely multiplying the quantity of automobiles parked in the designated location at each interval by the interval. it is described as (spacehours). 𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑙𝑜𝑎𝑑 = 𝑡𝑖𝑚𝑒 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙 (ℎ𝑟) ∗ ∑ 𝑝𝑎𝑟𝑘𝑒𝑑 𝑣𝑒ℎ𝑖𝑐𝑙𝑒𝑠 𝑎𝑡 𝑒𝑎𝑐ℎ 𝑡𝑖𝑚𝑒 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙 4. average parking duration is the amount of time a car is left parked in a space. an indication of how frequently a parking place becomes available is provided when the parking duration is presented as an average. it represents the proportion of total vehicle hours to the quantity of parked cars. 𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑑𝑢𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑙𝑜𝑎𝑑 /𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑣𝑜𝑙𝑢𝑚𝑒 5. parking turnover: is how frequently a parking place is used. it is calculated by dividing the volume of parking for a given time period by the quantity of parking spaces. 𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑡𝑢𝑟𝑛𝑜𝑣𝑒𝑟 = 𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑣𝑜𝑙𝑢𝑚𝑒 /𝑁𝑜. 𝑜𝑓𝑏𝑎𝑦𝑠 𝑎𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒 6. parking index: the term occupancy or efficiency also applies to the parking index. it is described as the proportion of the total space that is accessible to the number of bays that are occupied throughout time. it provides a total assessment of how well the parking space is used. parking index can be found out as follows: 𝑓 = 𝑃𝑎𝑟𝑘𝑖𝑛𝑔𝑙𝑜𝑎𝑑/ 𝑃𝑎𝑟𝑘𝑖𝑛𝑔 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦∗ 100 (1) 2. methodology the demand for parking lots varies by region. in this research, the city center of al-diwaniyah (commercial center, government departments and offices) was selected. al-diwaniyah city is the administrative, economic, and political center of al-diwaniyah governorate and one of the cities in 124 rania al-mrumudhi and jalal al-obaedi /al-qadisiyah journal for engineering sciences 15 (2022) 122–126 iraq in the middle euphrates region. fig 1 show the location of aldiwaniyah city. it is crucial to get parking information from urban streets in order to research the effects of on-street parking. al-orzady street, al saray street, and almuswreen street are the first three locations that have been chosen for this project to study its characteristics in the evening period. in al-diwaniyah city, these locations are among the busiest ones on-street parking. fig 2 show the border of study area. figure 1. a map of iraq showing the location of the city of diwaniyah figure 2. screenshot for the study area the number of all vehicles parked on and off streets in the study area was calculated at the morning and evening at different days, and the parking sites on the street were chosen using the gis application, which was also used to estimate the length of the street allowed for stopping. the attributes were ascertained using the in-out survey method. to find out why the car was parked on the street, a questionnaire was also created. 3. data collection the data of this study were collected for the purpose of finding the characteristics of parking in al-orzady street, al saray street, and almuswreen street at the evening period. the study does not include standing in the squares. the survey was conducted using the in _out method. where three ways were chosen in which vehicles are allowed to stop, the survey that was conducted counted the number of vehicles parked on the street at the beginning of the survey, and counted the number of vehicles that parked or left the street at certain periods of time. the fig 3 shows an aerial picture of the city canter of al-diwaniyah, showing the roads for which, the survey was conducted. streets for which properties were found st1 orzady street, st2 saray street and st3 street of almuswreen. table (1) show the information of on street parking in st1, st2, st3. figure (3) locations on street parking in the study area table 1. existing on-street parking survey in al-orzady street st1, al saray street st2, and almuswreen street st3. then a survey was conducted to determine the number of parked vehicles in all of the streets of al-city diwaniyah's centre in the study area, as well as the number of parked vehicles in 22 parking spaces located in the city centre of al-diwaniyah. fig 4 show the location of on street and off street parking lots in the study area. figure 3. location on-street parking in the study area street name width (m) length( m) number of lanes direction of flow number of spaces type of parking st1 13m 90m 2 one way 20 one side (45 angle) st2 10m 290m 2 two way 50 both sides (parallel) st3 20m 195m 2 two way 43 both sides (parallel) figure 4. screen shot for all roads and parks in the study area 125 rania al-mrumudhi and jalal al-obaedi /al-qadisiyah journal for engineering sciences 15 (2022) 122–126 a questionnaire was undertaken in al-orzady street, al saray street, and almuswreen street. 60 vehicles were taken in the streets to determine the reason of parking a vehicle on the street, as well as the duration the vehicle was parked. according to the instructions on the questionnaire sheet. shown in table (2). table 2. the questionnaire sheet 4. results and discussion in this research, what was inferred from the data collected in al-diwaniyah city center, where it was found that the total number of vehicles that parked on the street and the total number of vehicles parked in the parking. it was found that the number of vehicles parked in the street is twice the number of vehicles in the parking are as shown in the table (3) and table (4) show the characteristics of on street parking at the evening in al-orzady street , al saray street and almuswreen street. table 3. the demand for on-street and off-street parking for all of the local parked vehicles (22 park). parking type no. of parked vehicles thursday 10:00am. (2/12/2021) friday 4:30 p.m. (3/12/2021) wednesday 10:00am. (8/12/2021) wednesday 4:30p.m. (8/12/2021) off-street 749 805 586 546 on-street 1626 1501 1539 1250 total 2375 2306 2125 1796 table 4. the parking characteristics for the selected on-street parks at the evening figure 5. the accumulative curve for on street parking from fig 5 found that the peak times for al-orzady street st1 are at (4:10 and 4:40 pm), al saray street st2 (3:10 and 3:20) while the peak times for almuswreen street st3 are at (3:10, and 3:40 pm), because it is located in the center of al-diwaniyah, which is the commercial and administrative center of the city. where these time periods are considered the time when most people perform their work in commercial areas and areas that contain medical centers, and after this time we notice a decrease in the number of vehicles parked on the street. what was discovered from the questionnaire survey that took place in st1, st2, and st3 to determine the reason for parking the vehicle on the street, as show in the fig 6. figure 6. the percentage of purpose of stopping the majority of parked vehicles are for the purpose of shopping, at a rate of 55%, 38 percent are for shop owners, and 7% are for the purpose of visiting medical facilities, as seen in the fig 6. what has been observed in the roads that have been studied is that the process of parking vehicles on the street occurs on a daily basis and can have a number of negative consequences, including a negative impact on traffic flow and a reduction in vehicle speed as a result of obstructing traffic, as well as a negative effect on road capacity and congestion. the name of on street which vehicles are allowed to park in it st1 st2 st3 car no. the reason for stopping, the vehicle the time of stopping vehicle shopping shop owner doctor review min hr. street name st1 st2 st3 peak time 4:10pm 4:40pm 3:10pm 3:20pm 3:10pm 3:40pm peak parking accumulation 0020 0045 0044 parking load 2030 4860 4810 parking volume 0030 0059 0058 parking index 37.59% 69.8% 93.22% parking duration 67.670 82.37 82.93 parking turnover 0.670 1.017 1.348 38% 7% 55% purpose of stopping 126 rania al-mrumudhi and jalal al-obaedi /al-qadisiyah journal for engineering sciences 15 (2022) 122–126 5. conclusions the following conclusions are based on this study: 1the peak time for st1(4:10 and 4:40 pm), st2 (3:10 and 3:20) and, st3 are at (3:10 and 3:40 pm). 2the average turnover for st1, st2, st3 are (0.67, 1.017, 1.348). this suggests that the efficiency of existing parking spaces with low average turnover is less performance 3the high value of parking index in st3 93.22% while the low value in st1 37.59% 4some people prefer to park the car on the street, because free parking. 5most of the vehicles parked on the street are for the visiting shopping center, because commercial area is the main area in the city, where it attracts large numbers of people for shopping, in addition to government departments, offices and nearby banks, so this area needs to provide parking for vehicles with a high capacity and provide protection for the vehicle. 6the paper indicates promoting advanced mobility technologies, such as smart parking. references [1] murad, a.a., creating a gis application for retail centers in jeddah city. international journal of applied earth observation and geoinformation, 2003. 4(4): p. 329-338. 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[22] mahmoud, t. s. 2011. الرمادي مدينة مركز في السيارات مواقف كفاءة anbar .تقويم journal for engineering sciences al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� nonlinear finite elemen analysis of high stregth reinforced concrete slabs abstract this study describes a three-dimensional material nonlinear finite element model suitable for the analysis of high strength reinforced concrete slabs under different states of loading. the twenty-node isoparametric brick element has been used to model the concrete while reinforcing steel bars have been idealized as axial members embedded within the brick elements. the behavior of concrete in compression is simulated by an elasto-plastic work hardening model followed by a perfectly plastic response, which is terminated at the onset of crushing. in tension, a smeared crack model with fixed orthogonal cracks has been used with the inclusion of models for the retained post-cracking tensile stress and for the reduced shear modulus. three high strength reinforced concrete slabs and one normal strength concrete slab have been analyzed in the present study with different boundary conditions and loading arrangements. parametric studies have been carried out to investigate the effect of some important finite element and material parameters. these parameters include the compressive strength of concrete, amount of reinforcement and slab thickness. the finite element analysis indicated that when the concrete compressive strength of the slab is increased from (35 mpa) to (80 mpa) an increase in the ultimate capacity of about (60%) has been achieved. in general good agreement between the finite element solutions and the available experimental results have been obtained keywords: finite element ; brick element; high strength concrete slab ; plasticity models; compressive strength ������� ��� �� ����� ������ ���� ������ ����� � � ���! �"#��$ ����% ���&$ ���� ��) �����8 =d�=9 ا: )� د �� ��� ا�)7 ��t ا�����دة ������+ ا����9 ت ا��4 * �rذu�)أ �� ا������� ذات ا��� و��� /%x هvw ا��را ��� *ت ��4�n� �$ ا���� ا�)� ��=-/ y�/ +� . �) �� a n���ة ���?��+ ا��4�z(د ذي ا� أ�� ./0 ا���4ام ا�)7%� ا�� d u ا�?d=9 ا: ) ���4ام 7a%� أ� دي ا��)� \��?�/ 0/ ��q "��ا��� � (�) ��uري(��� (� /�u��� . yر 7a dq%� ا��4�/0 /�?�+ /%�ف ا��4 ���4ام ا�u��7ذج ا����ن 5 دات ا�[�. rا*($ -ا �� u�ن ذو ا�����ــ�ـ�� ا�� ()elasto – plastic strain hardening( عuوا���ـ�ـ� dr. ihsan a. s. al-shaarbaf assist. prof. university of nahrain munaf a. a. al-rmahee assist. lecture university of qadisiya �'�"�� ()�*� � % +�,$ � % -��" �%�&" ./�" ������� 0�"�12����3 ���4 -�!��5� 67�� ��% 8�&'9 /:�4�� �%�&" ;���< =��,�� 0�"�1–����3 ���4 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� (� ) perfectly plastic( �%�ف �ـ�ن /ـ م�� �� أ �%@ ا($)� ل ا(�[� ط /�v��7a 0z�5 ا��4�� ���� �5 دات . rا ��=-�/ y��/ أ�� �z�7ا�� c�zذج ا��u�) d7�/ 0/ ��q �zا�)smeared crack model ( ذجu�)-� �) (���5 دات آ� /�y ا*rر ا ���a*ا ��e7 w�8 f��ا� +�� (� ���� g��$4�� ذجu��)وأ c�zا��� ��( �) �� )�� ��%uل ) shear modulus of rigidity(ا��z ا�������� d�q ا��4 c�zت . ا��* د �� ذات ��a و��� ���� ا��� و��� و ���9 وا���ة ذات ��a ������ ��) ����9 ت �8 + =9=�� ���0 /��/ ��dq هvw ا��را 7 د و/� � (� .��+ ��4�$� إ�� �ة ��را�� /-=�� )g ا������ات ا����5 آ��� ا���)��� ��rw�7 و/�?�+ u8اص ا��4�a رب k/ y �rأ ��� ا��� و�� a ، ا����دة �t (� .و/�� ا���/��� �� �� /���+ ا�)7��آ���� �� �� ، /�[�y7 ه�vw ا�������ات �� و��� ا*(�[� ط ���4 (� dq ا���9 ت � n �y7 ا��7 #l. ا�����" و��� ا����9� دة �� و�� ا*([� ط ���4 ) mpa 80(إ��@ ) 35mpa( ا�������� ن ز dا�u� @% :دة ا���+ ا ���rا ��� ). 60%( <دي إ�@ ز��qاu/ d��( �\ إن ا�����+ ا�d=9= d�89 ا: ) د a رةu% �rو � و .ا��7 #l ا�)���� notation cp plasticity coefficient ec modulus of elasticity of concrete es modulus of elasticity of steel reinforcement f yield function f'c uniaxial compressive strength of concrete ft uniaxial tensile strength of concrete fy yield stress of longitudinal reinforcing bars or stirrups i1 first stress invariant j2 second deviatric stress invariant ni shape function of node i of the brick element u,v,w displacement components in the x,y and z-direction x,y,z global coordinate system v poisson's ratio α1, α2 tension-stiffening parameters c matreial constant β shear retention factor or material constant σn, σc stress σo effective stress at onset of plastic deformation σcr cracking stress εn, εc strain εcu concrete ultimate strain εo strain corresponding to peak uniaxial concrete compressive stress εcr cracking strain γ1, γ2, γ3 shear retention parameters ρ longitudinal reinforcement ratio ξ,η, ζ local coordinate system al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� introduction the development of concrete technology and practice has led to a changing perception of what is high strength concrete. the term high strength concrete is generally used for concrete with compressive strength higher than 41 mpa (rasmussen et al.1995).its use in construction industry has increased steadily in recent years because it results in reduced dead loads, which leads to longer spans and taller structures. however high strength concrete is considered to be a relatively brittle material because the postpeak portion of its strain-stress diagram descends deeply or almost vanishes as the compressive strength increases (baksh et al.1990). the inverse relationship between strength and ductility is a series drawback in using this material. in spite of the wide use of high strength concrete, little information is available on the structural behavior of this new material. in the last decade, extensive research work has been conducted on the structural behavior of high – strength beams and columns. little investigations of the structural behavior of two way slabs are available. at present, the finite element technique is considered as the must efficient numerical approach for analyzing reinforced concrete members. this technique has been adopted in this research work to analyze high strength reinforced concrete slabs. in this analysis, the slab is divided into a number of three dimensional brick elements. the behavior of reinforced concrete is governed by many factors, such as the tensile stress redistribution after cracking , crushing of concrete, nonlinear inelastic stress-strain relation for concrete in compression and yielding of steel reinforcement. finite element model the twenty-node isoparametric brick element shown in figure (1) is used in the current study to model the concrete. each node of this element has three degrees of freedom u, v, and w in the x, y, and z directions respectively. the definition of the displacements within the brick element is given by : ( ) ( ) ( ) ( ) ( ) ( )∑ ∑ ∑ = = = = = = 20 1 20 1 20 1 .,,,, .,,,, .,,,, i ii i ii i ii wnw vnv unu ζηξζηξ ζηξζηξ ζηξζηξ where ni (ξ, η, ζ) is the shape function at the i-th node and ui, vi, wi are the corresponding nodal displacements. the shape functions for the 20 node brick element which are adopted to map the element are given in table(1). the three-dimensional finite element problems require a relatively large amount of computation time because considerable proportion of which is used in the numerical integration in order to setup the elements stiffness matrices. the gauss-legender quadrature numerical integration scheme has been found to be accurate and a convenient technique to carry out the finite element analysis. the integration rule, which has been used in this study , is the (1) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� twenty seven point rule. also the (15a), (15b) and 8point rules are used in this research as a parametric study in order to show the effect of using these rules on the finite element solutions compared with the twenty seven point rule. the corresponding weights and abscissa for the 27point rule are listed in table(2) and the relative positions of the sampling point over the volume of outline of the computer program the computer program 3dnfea (3-dimensional nonlinear finite element analysis) has been used in the present study(al-shaarbaf.1990). in the current research work, the computer program has been generalized to deal with high strength concrete as well as normal strength concrete slabs. the main objective of the computer program is to analyze reinforced concrete members under general three-dimensional states of loading up to failure. in the present study ,the computer program had been proceed using fortran 90(power station 4.0) compiler . the program has been implemented on pentium iv, 1700mhz ibm compatible computer with 256 megabyte ram. modeling of material properties the material model used in the present work is suitable for the three-dimensional nonlinear analysis of reinforced concrete structures under monotonically increasing load. the behavior of concrete in compression is presented by an elastic-plastic strain hardening model followed by a perfectly plastic response, which is terminated at the initiation of crushing. the growth of subsequent loading surfaces is described by an isotropic hardening rule. a parabolic equivalent uniaxial stress-strain curve shown in figure (3) has been used to represent work hardening stage of behavior and the plastic straining is controlled by an associated flow rule. a yield criterion suitable for analyzing reinforced concrete members has been used. this criterion was used successfully can be expressed as: (2) where c and β are material parameters to be determined by fitting biaxial test results. using the uniaxial compression test and the biaxial test under equal compressive stresses. i1 and j2 are the first stress and second deviatoric stress invariants and σ0 is the equivalent effective stress taken from uniaxial tests. in tension, linear elastic behavior is assumed to occur prior to cracking. crack initiation is controlled by a maximum tensile stress criterion. a smeared crack model with fixed orthogonal cracks has been adopted to represent the behavior of cracked sampling points. the retained post-cracking tensile stress and the reduced shear modulus are calculated according to figure(4) and figure(5) respectively. details of the plasticity based model in compression and the smeared crack model in tension can be found elsewhere (al-rmahee.2005). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� analysis of high strength reinforced concrete slabs in this section, two high strength reinforced concrete slabs have been analyzed using the finite element technique and the models described in the pervious section. the selected slabs are two-way slabs and were simply supported along their four edges at a distance (100mm) from the edges with the corners being free to lift . the selected slabs failed in flexure. the three dimensional nonlinear finite element techniques have been used for the analysis using the computer program (p3dnfea).the finite element results have been compared with the available experimental data. in the following sections a description of the slabs and the validity of the finite element analysis are presented. analysis of high strength reinforced concrete slab (hs1) a simply supported two-way high strength reinforced concrete slab designated as hs1 was analyzed to investigate the applicability and accuracy of adopted finite element models. this slab was selected from the experimental tests carried out by marzouk and hussein (4) in 1990 .the obtained analytical results have been compared with the results reported in reference no.4 . the slab is loaded by a concentrated load through a column stub at the center of the slab. the dimensions and reinforcement details are shown in figure (6). material properties of the analyzed high strength slab are listed in table(3). by taking advantage of symmetry, a segment representing one-quarter of slab was taken in the finite element modeling. this segment was divided into (149) brick elements. another finite element mesh has also been used to asses the accuracy of the finite element model. these mesh consisted of (100) brick elements, figure (7). results of analysis the analytical load –mid span deflection curves obtained for the two meshes considered are compared with the available experimental data as shown in figure (8) .from this figure it can be noted that the finite element solutions are in good agreement with the experimental results for both meshes throughout the entire range of loading. the results obtained using the mesh with (149) elements are closer to the experimental results compared with those obtained using the mesh of (100) elements. it can be observed that for the analytical curve obtained for the first mesh (149 elements), the ultimate load was (175) kn (1.7 % less than the experimental ultimate load). the deflection at ultimate load was (25.7)mm (1.01% greater than the corresponding experimental value). for the second mesh(100 elements), the ultimate load was (188) kn (1.056% greater than experimental ultimate load). the deflection at ultimate load was (25.5)mm (1.001% greater than the corresponding experimental value). figure (9) shows the stress distribution along a typical middle steel bar and a steel bar located at edges of the slab obtained from finite element analysis at the last converged increment of loading. it can be shown that a maximum tensile stress of (385 mpa) occurred at the center of the middle bar. it was also observed that small stresses occurred at region located at the support. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� analysis of high strength reinforced concrete slab.hs11 a simply supported two-way high strength reinforced concrete slab was analyzed to investigate the validity and accuracy of the adopted finite element models. this slab (designated as hs11) was also chosen from the experimental tests carried out by marzouk and hussein (4) .the analysis results obtained have been compared with the available experimental data. this slab differed from slab hs1 in its thickness, reinforcement ratio and concrete compressive strength. the obtained analytical results have been compared with the experimental results reported in reference no.(4). the slab is loaded by a concentrated load through a column stub at the center of slab. dimensions and reinforcement details of the slab are shown in figure (9). material properties of the analyzed high strength slab are listed in table (4). the selected quarter of the slab was discritized into (100) finite elements with two elements through the slab thickness. a second finite element mesh was used to study the accuracy of the finite element model. the second mesh consisted of (50) brick elements with one element through the slab thickness, figure (10). results of analysis figure(11) represents the analytical load-deflection curves compared with the experimental load-deflection curve for the two used meshes. from this figure, it is observed that the finite element response is in good agreement with the experimental results up to a load level of (80) kn. after this stage of loading a relatively stiffer analytical response is obtained up to (144) kn. it can be shown that the results obtained using the mesh of (100 elements) are closer to the experimental result compared with these obtained using the mesh of (50 elements).the predicated ultimate load obtained using the mesh of (100 elements) was (195) kn (0.6 % less than the experimental ultimate load). the deflection at ultimate load level was (27.4)mm (1.014% greater than the corresponding experimental value). for the mesh of (50 elements) the ultimate load was (205) kn (1.045% greater than the experimental ultimate load) and the deflection at ultimate load level was (26.054) mm (3.6%less than the corresponding expe rimental deflection ). also figure (12) shows the stress distribution along a typical middle steel bar obtained from finite element analysis at the last converged increment of loading . it can be shown that a maximum tensile stress of (512.5mpa) occurred at the center of the middle bar. it was also observed that small compressive stresses occurred at region located at the support. parametric study in this section, selected slabs were analyzed to investigate the effect of some important material and solution parameters on the numerical load deflection response and ultimate capacity. the investigations considered in the study include the effect of grade of concrete, amount of reinforcing steel and slab thickness. the parameters related to the finite element solutions are the tension stiffening model, integration rule and convergence criteria. the al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� parametric studies are based on the models and techniques described in the previous sections. the finite element analyses presented in this section have been generally carried out by considering material nonlinearities. the modified newton – raphson solution techniques has been used with a work done convergence criterion having a tolerance of 3%. effect of grade of concrete the two high strength reinforced concrete slabs tested by marzouk and the normal strength reinforced concrete slab, which have been described in the previous section, are used to study the influence of the grade of concrete on the behavior and ultimate loads. it was found that the behavior of the slabs with low compressive strength of concrete is softer than those of concrete having higher strengths. the analysis result indicates that an increase in the compressive strength by about 10 % leads to an increase in the ultimate load by about 4 %. figures (13) and (14) show the response of the considered high strength reinforced concretes slabs for different concrete compressive strength. figures (15) and (16) show the effect of the compressive strength of concrete on the stress distribution of a typical middle steel bar of the high strength reinforced concrete slab (hs1) and the (hs11). it can be shown that an increase in the value of compressive strength by (25%) leads to a decrease in the maximum tensile stress in steel by about (18%), while by decreasing the compressive strength by (25%) leads to an increase in tensile effect of slab thickness to study the influence of using different slab thickness on the behavior of high strength reinforced concrete slabs, slab (hs11) was reanalyzed with three different values of thickness. the selected values were (45), (90) and (135) mm. the load – deflection curves obtained from the finite element analysis together with the experimental test results (slab thickness 90 mm) are shown in figure (17). the finite element results reveal that a considerable increase in the ultimate load capacity has been achieved by increasing the slab thickness. the ultimate load obtained for thicknesses of (45), (90) and (135) mm are (160), (195) and (225) kn respectively. it can be noted that an increase in the slab thickness of 50% leads to an increase the ultimate load by about 15% while decreasing the thickness to 50% leads to a decrease in the ultimate load by about 18%. effect of amount of reinforcement: figure (18) shows the effect of using of different amounts of reinforcement on the loaddeflection behavior of slab (hs1) .four different steel ratios were used for the finite element analysis. obviously, a stiffer analytical response was noticed for with high amount of steel. it can be noted that the deflection of the slab at ultimate load was decreased with increasing the amount of steel. the finite element analysis indicated that the ultimate capacity is increased by about (25%) when the steel ratio is increased by (50%). figure (19) shows the profile al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� of steel stresses along the length of a typical steel bar located at the mid-span of slab (hs1) for different steel ratios. it is shown that the steel stresses dropped sharply with the distance from the slab center. effect of integration rule the influence of using different integration rules on the load deflection curve of slab (hs11) are shown in fig. (20). the slab has been analyzed using the 27, 15a, 15b and 8 point rules. the predicted load-deflection curves are generally in good agreement with the experimental results. the 27-point integration rule resulted in a predicted response closer to the experimental behavior. this can be attributed to the relative distribution of sampling points within the brick element. a relatively stiffer response has been obtained for the 8point rule while a softer behavior has been obtained using the 15 a and 15 b rules. the cpu time recorded at the end of the last converged increment of loading were (8.12), (16.26), (14.39) and (30.41) minutes for the 8, 15a, 15b and 27-point rules respectively. therefore, the 27-point has been used for all analysis considered in the current research work. summary and conclusions a nonlinear finite element analysis of high strength reinforced concrete slabs using a full three dimensional model have been presented. the main objectives of this study are to investigate the accuracy and efficiency of the computational finite element models in simulating the structural behavior of structures. the adopted material constitutive relationships are based on the incremental theory of plasticity of concrete in compression and the smeared crack representation of concrete in tension with an elastic-linear work hardening model used to simulate the behavior of reinforcement. several parametric studies have been carried out in the current research to investigate the effect of some material and numerical parameters on the predicted behavior of the high strength reinforced concrete slabs. based on the finite element analysis carried out throughout the present work, the following conclusions are drawn: 1. the three – dimensional finite element model used in the present research work is capable to simulate the behavior of high strength reinforced concrete slabs. the finite element solutions obtained for different slabs are in good agreement with the corresponding experimental results. 2. the finite element analysis indicated that when the concrete compressive strength of the slab is increased from (35 mpa) to (80 mpa) an increase in the ultimate capacity of about (60%) has been achieved. 3.the finite element analysis indicated that the increase in the compressive strength of concrete from (67mpa) to (80mpa) leads to a decrease in the maximum tensile stress in steel by about (18%).while when the compressive strength of concrete decreases from (67mpa) to (52.5mpa) an increase in tensile stress in steel by about (15%) is obtained . al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 4. the finite element solutions reveal that the ultimate load of the considered slabs increases with the increase of the amount of reinforcement, when the steel ratio is increased by about (50%) an increase in the ultimate load capacity by (25%) is achieved. 5. according to finite element analyses conducted in this work , it is found that by increasing the slab thickness from (90mm) to (135mm) a considerable increase in the ultimate load capacity about of (15%) is obtained. also by decreasing the thickness of slab from (90mm) to (45mm) a decrease in ultimate load capacity of slab by (18%) is achieved. 6. throughout this research work, the (27), (15a), (15b) and (8) point integration rules have been used. the load deflection behavior obtained using the 27-point integration rule has been compared with those obtained by using (15a), (15b) and (8) point rules. the finite element solutions reveal that the results of the 27point rule are closer to experimental data compared with the results of the other rules. the (cpu) time recorded for the (15a), (15b) and (8) integration rule was less than recorded for the (27) integration rule by (70%), (40%) and (44%) respectively. references 1rasmussen, l.j. and baker, g. "torsion in reinforced normal and high strength concrete-part 1 : experimental test series" aci journal, 1995, pp.149-155. 2baksh, a.h., wafa,f. and akhtaruzzaman,a.," torsion behavior of plain high strength concrete beams" aci-structural journal,1990,pp.583-588. 3al-shaarbaf, i.a.s., "three-dimensional nonlinear finite element analysis of reinforcement concrete beams in torsion" phd thesis. university of bradford, 1990. pp.323 4marzouk .h. and hussein, a. experimental investigation on the behavior of high – strength concrete slabs. acl. structural journal, vol. 88.no.6, 1991, pp.701-713. 5al-saidi, b.a.s. "nonlinear finite element analysis of reinforced concrete slabs" m.sc. thesis .university of al-nahrain, 2003.pp124. 6al-rmahee, m.a.a “nonlinear finite element analysis of high strength reinforced concrete slabs” m.sc. thesis. university of kufa, 2005. pp111. table (1): shape functions of the twenty-node isoparametric element location i ξ ηηηηιιιι ζζζζi ni ( i ξ , ηηηηi, ζζζζi) corners nodes ±1 ±1 ±1 0.125(1+ξξi)(1+ηηi)( ξξi+ηηi+ ζζi -2) mid-side nodes 0 ±1 ±1 0. 25(1-ξ2)(1+ηηi)( 1+ ζζi) mid-side nodes ±1 0 ±1 0. 25(1+ξξi)(1-η 2 )( 1+ ζζi) mid-side nodes ±1 ±1 0 0. 25(1+ξξi)(1+ηηi)( 1ζ 2 ) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� table (2): weight and abscissa of sampling points used in this study integration rule sampling point number ξξξξ ηηηη ζζζζ weight 1,3,5,7,19,21,23,25 ± 0.7746 ± 0.7746 ± 0.7746 0.171468 2,6,20,24 ± 0.7746 0 ± 0.7746 0.2743 4,8,22,26 ± 0.7746 ± 0.7746 0 0.2743 10,12,14,16 0 ± 0.7746 ± 0.7746 0.2743 13,17 0 ± 0.7746 0 0.43895 9,27 ± 0.7746 0 0 0.43895 11,15 0 0 ± 0.7746 0.43895 27(3*3*3) 18 0 0 0 0.70233 table (3): material properties and finite element parameters used for slab, hs1. ft=0.1fct ; + h=es/15; ec=4700(fć)0.5; εcu=(4.0-fć/45) * 10 -3 concrete specification compressive strength, ƒ >c(mpa) 67 young's modulus, ec (gpa) 38.47 tensile strength , ƒt (mpa) 6.7 poisson's ratio ,ν* 0.20 uniaxial crushing strain ,εcu 0.0025 steel specification young's modulus , es(gpa) 190 yield stress ƒy (mpa) 496 hardening parameter + , h 12.66 poisson's ratio ,ν* 0.25 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� table (4) material properties and finite element parameters used for slab,hs11 . ft=0.1fct ;+h=es/15(73); ec=4700(fć)0.5; εcu=(4.0-fć/45) figure. (1): twenty-node brick element concrete specification compressive strength, ƒ >c(mpa) 70 young's modulus, ec (gpa) 39.323 tensile strength , ƒt (mpa) 7.0 poisson's ratio ,ν* 0.20 uniaxial crushing strain ,εcu 0.004 steel specification young's modulus , es(gpa) 190 yield stress ƒy (mpa) 496 hardening parameter + , h 12.66 poisson's ratio ,ν* 0.25 1 8 4 12 16 19 15 18 14 10 5 2 9 7 20 3 6 17 11 13 ηηηη ξξξξ ζζζζ x,u y,v z,w al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (2) distribution of the sampling points figure (3): uniaxial stress-strain curve for concrete in compression. ξξξξ ηηηη ζζζζ 2 3 4 5 6 7 8 9 1 14 15 16 13 18 17 12 11 10 23 24 25 22 27 26 21 20 19 εc εu ε0 ε' o e 1 f'c σc cpf’c al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� γγγγ2 εεεεcr γγγγ1 εεεεcr εεεεn ββββ γγγγ3 3 cr n 1 1 32 1 γγγγ++++      εεεε εεεε −−−−γγγγ −−−−γγγγ γγγγ−−−−γγγγ ====ββββ 1.0 γ1= 10.0 γ2= 0.5 γ3= 0.1 figure (5): shear retention model for cracked concrete. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (6): geometry, boundary conditions, loading arrangement and reinforcement details of slab hs1 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure.( 8) load-deflection behaviour of slab, (hs1) figure (7) finite element meshes used for slab, hs1 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (9) slab hs1, stress distribution in steel bar at load level ( 178 kn) figure (9) geometry, boundary conditions, loading arrangement and reinforcement details of slab hs11 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� figure (10) finite element meshes used for slab, hs11 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� figure (11)load-deflection behaviour of slab (hs11) figure (12) slab hs11, stress distribution in the middle steel bar at load level (198 kn) 0 25 50 75 100 125 150 175 200 225 0 5 10 15 20 25 30deflection(mm) l o a d (k n ) experim ental(fc`=67 mpa) fc`=35 mpa fc`=50 mpa figure (13) effect of concrete compressive strength on the loaddeflection behavior of slab hs 1 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (14) effect of concrete compressive strength on the load-deflection behavior of slab hs 11 figure (15) slab hs1, effect of concrete compressive strength on the stress distribution of a middle steel bar figure (16) slab hs11, effect of concrete compressive strength on the stress distribution of a middle steel bar al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 0 25 50 75 100 125 150 175 200 225 250 0 5 10 15 20 25 30mid-span deflection(mm) a p p l ie d l o a d (k n ) experimental(t=90mm) t=45mm t=90mm t=135mm figure (17) effect of thickness of slab on the load-deflection curve of slab hs11 0 25 50 75 100 125 150 175 200 225 250 0 5 10 15 20 25 30 mid-span deflection(mm) a p p l ie d l o a d (k n ) experi mental steel rati o=0.245% steel rati o=0.491% steel figure (18) effect of amount of reinforcement steel on the load –deflection behavior of slab hs1. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� -100 0 100 200 300 400 500 0 250 500 750 1000 1250 1500 distance from edge of slab(mm) t e n s il e s tr e s s (m p a ) stee l ratio=0.245% stee l ratio=0.491% stee l ratio=0.736% figure (19) slab (hs1), stress distribution along a typical middle steel bar 0 25 50 75 100 125 150 175 200 225 0 5 10 15 20 25 30mid span deflection(mm) a p p l ie d l o a d (k n ) experimental 27 rule 15a rule 15b rule 8 rule figure (20) effect of integration rule on the load-deflection behavior of slab hs11 article al-qadisiyah journal for engineering sciences 15 (2022) 094–101 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: noors301@uowasit.edu.iq ( noor s najem) https://doi.org/10.30772/qjes.v15i2.819 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. experimental study of natural convection heat transfer enhancement in a square cavity filled with nanofluid using magnetic effects noor s. najem*, hadi o. basher, and mohammed d. salman mechanical engineering department, wasit university, college of engineering, iraq a r t i c l e i n f o article history: received 15 may 2022 received in revised form 14 june 2022 accepted 22 july 2022 keywords: natural convection, heat transfer, square cavity, nanofluid, magnetic effects. a b s t r a c t researchers in heat transfer are paying close attention to nanofluids because of their potential as high performance thermal transport media. in light of natural convection's enormous significance, the addition of nanoparticles significantly enhances the thermophysical properties of the nanofluids compared to the base fluid. in this study, experimental work was used to evaluate the influence of cuo nanoparticles on natural convection with magnetohydrodynamic (mhd) flow in a square cavity. the cavity’s left and right vertical walls were maintained at different temperatures, and the top and bottom walls of the cavity were insulated. this experimental study applied a horizontal magnetic field with uniform strength. results w ere obtained for a variety of hartmann numbers ranging from 0–300, rayleigh numbers going from 2.76e+8 to 6.89e+8, and solid volume fractions ranging from 0 to 1.5%vol. results showed that the heat transfer coefficient and nusselt number values decreased with the increase in the values of the hartmann number, except for the heat transfer coefficients at ha=100 and 150 are larger than the heat transfer coefficients at ha= 0. the maximum heat transfer coefficient and nusselt number enhancement were 40.8% and 28.5%, respectively, at a 1.5% volume concentration of cuo-water nanofluid, ra= 6.7e+8 and ha=100 compared with pure fluid (water) at ha=0. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction in recent decades, there has been a growing recognition that fluid movements and transport processes caused or influenced by buoyancy are of interest and relevance in many scientific and technological domains, particularly in engineering and science. this topic is currently being discussed in conferences and journals that cover a wide range of issues, including meteorology, geophysics, astrophysics, nuclear reactor systems, materials processing, solar energy systems, energy storage and conservation, fire control, the chemical, food, and metallurgical industries, as well as the more traditional fields of fluid and thermal sciences, among others. in order to meet the ever-increasing power requirements, it is imperative that every method of enhancing the efficiency of powergenerating cycles be explored. therefore, it's worth thinking about the working fluid utilized while improving the power cycle. in addition, there should be further research into whether nanofluids can be used in any thermal transport system due to their potential as a novel heat transfer fluid and their relative simplicity of integration into an existing design. in recent decades, researchers have looked at using 'micro' or 'nanosized particles to improve heat dispersion [1]. solids have superior thermal conductivity properties to liquids. as a result, current scientific technology uses nanometer-sized solid particles, often with a diameter of less than 50 http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i2.819 https://doi.org/10.30772/qjes.v15i2.819 http://creativecommons.org/licenses/by/4.0/ noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 95 nm. choi [2] is the first to use the word nanofluid, which refers to a colloidal mixing of nanoparticles and a base fluid that has been described before. the majority of the studies have demonstrated that metallic particles transmit more heat energy than non-metallic particles when compared to one another. pordanjani et al., 2019 [3] investigated the effect of a heat source and its location on natural convection in a c-shaped enclosure saturated with a nanofluid. different rayleigh numbers (103-106) and solid volume percentages of the nanofluid were considered (0-0.05). the results show that the highest nusselt number is achieved with the heat source in the top horizontal cavity at ra = 103. therefore, it is recommended to use high rayleigh numbers (ra = 106) and vertical cavities. high rayleigh numbers cause the highest increase when the heat source is in the vertical axis's upper part. mohebbi et al. 2019 [4] used the lattice boltzmann approach to measure the heat transfer from a nanofluid thermosgravitational enclosure to a local heater (lbm). the influence of the rayleigh number (103–106), cavity aspect ratio (0.2–0.6), nanofluid solid volume fraction (0–0.05), heater height and placement, as well as other liquid circulation and heat transfer factors, were studied in this work. the mean nusselt number climbed as the rayleigh number and nanoparticle concentration grew. the mean nusselt number is highest when the heater is on the left border, consistent with earlier studies. izadi et al., 2018 [5] studied the natural convection of cu-water nanofluid within a wavy wall enclosure with a cylindrical heater. the results indicated that raising the solution's temperature reduces homogeneity. moreover, the average nusselt number of both porous phases increases with the brownian parameter but decreases with the thermophoresis factor. torki and etesami, 2020 [6] investigated the natural convection heat transport of sio2/water nanofluids in a rectangular container at varied concentrations and tilt degrees. the findings demonstrated that nanofluid heat transfer characteristics did not change significantly at low concentrations. however, when the volume concentration of nanoparticles is greater than 0.005, the heat transfer coefficient declines. roy et al. 2018[7] proposed a model for exploring the spontaneous convection of a nanofluid between two square enclosures. the flow intensity rises with the volume of nanoparticles and the rayleigh number. the nusselt number increases roughly linearly in the inner and outer cylinders as the nanoparticle volume concentration increases, yet the rayleigh number increases exponentially. a magnetic field may affect natural convection in various practical applications. consequently, interest in the flow behavior and heat transfer mechanism of enclosures filled with electrically conducting fluids and subjected to a magnetic field has increased [8]–[16]. these investigations agree that the fluid inside the enclosure feels a lorentz force due to the magnetic effects. this force affects both the buoyant flow field and the heat transfer rate. mourad et al., 2021 [17] studied the natural convective flow and heat transfer in the cold wavy enclosure and the hot elliptic cylindrical. alumina nanoparticles are added to the water to improve heat exchange. a drop in the nusselt number values of up to 22.22 percent is offered when ha is changed from 0 to 100. dogonchi et al., 2020 [13] studied the heat transfer in a square enclosure under a magnetic field and nanoparticles using natural convection. the heat transfer rate in the presence of magnetic fields on the inner wall of the annulus increases as the rayleigh number, nanoparticle volume fraction increases, and decreases as the hartmann number increases. alsabery et al., 2018 [18] studied the conjugate mhd natural convection of al2o3-water nanofluid in a square cavity with a conductive inner block. according to the findings, the heat and mass transfer mechanisms and the flow characteristics within the enclosure are substantially influenced by the magnetic field intensity and the amount of heat generated. employing a velocity-vorticity formulation, reddy and murugesan, 2017 [11] examined double-diffusive natural convection in a square cavity with an external magnetic field. the results showed that the increase from 0 to 30 of ha had reduced nusselt and sherwood numbers by around 72 percent and 78 percent, respectively. mahmoudi, mejri, and omri, 2016 [16] have studied the natural convection of an al2o3-water nanofluid in two heat sinks vertically, and the horizontal walls were subjected to the magnetic field. the results showed that the heat transfer rate increases as the hartmann number grows and the rayleigh number increases. furthermore, the heat transfer rate rises linearly as the solid volume percentage of nanoparticles increases. dimitrienko and li, 2020 [19] investigated the laminar natural convection of a non-newtonian carreau fluid in a square cavity with a uniform magnetic field. the work has examined the effects of the rayleigh number (104 and 105) and the prandtl number (pr=0.065) on the cavity. the findings indicate that the heat transfer rate rises as the hartmann number lowers and the rayleigh number increases. mehran et al., 2017 [20] explored the topic of unsteady natural convection inside a square cavity separated by a flexible impermeable membrane. the cavity's horizontal walls are adiabatic, while the vertical walls are isothermal. a homogeneous magnetic field with varying orientations is applied to the cavity. the hartmann number affects the form of the membrane and heat transport inside the hollow. the magnetic field orientation angle also has a substantial impact on the form of the membrane and heat transport inside the cavity. liao and li, 2021 [21] quantitatively examined natural convection inside a square cavity under an angled magnetic field, emphasizing the heat transfer transition. the findings demonstrate that increasing the magnetic field strength alters the flow field significantly. the average nusselt number (numean) and the maximum streamline dropped with growing magnetic fields. this study aims to evaluate experimentally the effects of an applied magnetic field on a nanofluid in a square cavity driven by natural convection to propose a partial answer to this difficulty. this effect will be investigated via the completion of the following tasks: synthesis and characterization of the nanofluid, fabrication of the experimental equipment, and testing of the nanofluids under a variety of experimental settings. 2. experimental setup and procedure the experimental apparatus was designed and implemented at wasit university/faculty of engineering. a square chamber with dimensions of 100 x 100 x 100 mm3 was built to test the reaction of a range of nanofluids to natural convection. insulation is applied to all other walls except for two vertical walls, which are maintained at constant temperatures. it is enclosed in an insulating hardwood box to keep the cavity warm. a wire heater and a cooler device were used to achieve the steady wall temperature boundary condition. two thermocouples were placed near the hot and cold walls to measure their temperature. adjustments were made to the hot wall by the wire heater, which ranged from 40 °c to 55 °c, and the cold wall, which ranged from 5°c to 20°c. a magnetic field was created using permanent magnets. removable insulating material covered the magnets, and it was designed to fit neatly into the housing above and below the cavity. figure (1) shows the combinations of relevance in this investigation. a magnetic field line was generated in the direction of the required fluid flow, and the complete arrangement was selected to achieve this. it was decided to use 96 noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 configuration (a) in order to cover the whole cavity with a magnetic field that moves with the projected fluid flow. the issue with this configuration is that the magnetic field lines go in the opposite direction to the fluid along the insulated walls. figure 2. schematic depiction of the experiment's setup. figure 1. configurations of permanent magnets are used for exciting the magnetic nanofluid with: (a) four magnets located on the top and bottom of the cavity. figure 2. schematic depiction of the experiment's setup. 2.1 experimental procedure the measurements were carried out in a steady-state environment. each test case was provided adequate time to attain a steady state after the necessary adjustments in test circumstances, such as the heat flux and volume fraction of the nanofluid. changes in flux or fluid type requiring a long time were given a deadline of 60 minutes as the maximum. for example, the temperature records for an enclosure initially kept at room temperature for gr = 1.21* 109, ha = 0, and = 0% took the system 55 minutes to achieve a steady state when the hot plate temperature records varied by less than 1%. 2.2 preparation of nanofluids a two-step approach accomplishes the preparation of nanofluids. first, ultrasonic vibration (model, power sonic 410) is employed to disperse the nanopowder in the distilled water, as depicted in figure 3, used in the current study. (beijing deke daojin science and technology co., ltd.). the nanofluids are generated in the chemical measuring flask using ultrasonic vibration. the nanoparticles are precisely weighed with a computerized scale with seven numbers (ohaus, thornton co). the diameter of nanoparticles of cuo is 25nm, and the density is 6500 kg/m3. in contrast, water's density is 996.6 kg/m3. estimated nanopowder masses are based on the percentage of particle concentration, the known density of powder, and distilled water densities (syam sundar and sharma 2008) [22]. the equation for the mixture and the weights of the nanoparticles have been presented. the following formula represents this equation. 𝑾𝒑 = ∅ (𝟏−∅) 𝝆𝑷 𝝆𝑾 𝑾𝒘 (1) where w denotes the mass in grams and w and p denote the water and nanoparticle, respectively. the sem image in figure (4) depicts the dry nanoparticles tested in this study, which have a diameter of 25 nm and a purity of 99.99 percent, according to the manufacturer's report. all measurements were conducted in the laboratory of the mechanical engineering faculty, university of technology. the procedure and the types of equipment used in the measurements were described in detail. figure 3. an ultrasonic bath (model power sonic 410) was used for nanofluid preparation. figure 4. sem image of 25 nm dry of cuo nanopowder. nanofluids with two volume fractions for periods ranging from 24 hours to 48 hours after synthesis are shown in figures (5) (a)–(b). (a) (b) figure 5. stability of nanofluids, (a) cuo–dw for 1% after 48 hr, (b) cuo–dw for 1% and after 24 hr. noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 97 2.3 data reduction this section briefly explains non-dimensional terminology related to natural convection-dominated instances. also explored are certain natural convection-induced cavity flow empirical correlations. natural convectiondriven nanofluids are also included in this section. 2.4 the natural convection in a square cavity consider a container with two opposing walls that are both isothermal and adiabatic at the same time. conduction would be the most dominant heat transmission mechanism in this case if all of the buoyancy effects were removed. if buoyancy effects were considered, fluid would flow up and down, resulting in a flow of fluid from the cavity hot to the cold wall. furthermore, while considering the shape that the heat transfer rate takes via this cavity, the following comparison to a pure conduction situation may be drawn: 𝒒 = 𝑰 × 𝑽 (2) 𝒒 = 𝑨. 𝒉. (𝑻𝟏 − 𝑻𝟐) (3) where a is the cross-sectional area of the flow, the temperature differences between the hot and cold walls are represented by the letters t1 and t2, respectively. when seen from a global viewpoint, heat transmission via a cavity behaves as an enhanced form of pure conduction, as demonstrated by this experiment [19]. the results of the nusselt number are determined by: 𝑵𝒖 = 𝒉.𝒍 𝒌 (4) where h is the cavity's height and l is the distance between the hot and cold walls, equations 1.14 and 1.15 are valid for any pr range. effective thermophysical properties of the nanofluids. the dynamic viscosity was studied by corcione (corcione 2011) [23], who created an empirical correlation for it based on a vast quantity of experimental data from the literature. nanoparticles with diameters ranging from 25 nm were included in the database, which was suspended in base fluids. with temperature ranges ranging from 293 k to 333 k, nanoparticle concentrations ranging from 0.001 percent to 1.5 percent were used in the experiments. it is possible to write it as follows: 𝝁𝒏𝑭 𝝁𝑭 = 𝟏 𝟏−𝟑𝟒.𝟖𝟕( 𝒅𝒑 𝒅𝑭 )−𝟎.𝟑∅𝟏.𝟎𝟑 (5) where µnf is the effective dynamic viscosity of the nanofluid, µf is the dynamic viscosity of the base fluid, and df is the equivalent diameter of the base fluid. the molecule is given by: 𝒅𝑭 = 𝟎. 𝟏 [ 𝟔𝑴 𝑵𝝅𝒑𝑭 ] 𝟏/𝟑 (6) where m is the molecular weight, n is the avogadro number, and f is the base fluid mass density approximated at 293 k. there is a standard variation of 1.84 percent in the preceding effective viscosity equation. the effective thermal conductivity of hybrid nanofluids is calculated using the correlation given in the study by r.prasher et al., 2005, [49]. there are two terms for this correlation: the first term and the dynamic part due to brownian motion, which is the second term. the thermal conductivity correlation used is 𝒌𝒆𝒇𝒇 = (𝟏 + 𝑨𝑹𝒆 𝒎𝑷𝒓𝟎.𝟑𝟑𝟑𝝋) [ 𝒌𝒑+𝟐𝒌𝒑𝒇+𝟐(𝒌𝒑−𝒌𝒑𝒇) 𝝋 𝒌𝒑+𝟐𝒌𝒑𝒇−(𝒌𝒑−𝒌𝒑𝒇)𝝋 ] 𝒌𝒑𝒇 (7) the effective density of the nanofluid is given by pack and cho (1998) 𝝆𝒏𝑭 = ∅𝝆𝑷 + (𝟏 − ∅)𝝆𝑭 (8) where ρp and ρf are the densities of the nanoparticles and the base fluid, respectively. the effective specific heat at a constant pressure of the nanofluid (cp)nf is computed using the following equation khanafar et al., (2003) 𝑪𝒑,𝒏𝑭 = (𝟏−∅)(𝝆𝑪𝒑)𝑭 +∅(𝝆𝑪𝒑),𝒑 (𝟏−∅)𝝆𝑭+∅𝝆𝒑 (9) 3. result and discussion the natural convection heat transfer properties for 1.5, 1, 0.5, and 0.1% cu/water solutions at constant particle sizes, in a rectangular enclosure are explored experimentally in this section. the experimental work was carried out on the rectangular enclosure side walls at varying temperatures, with ra numbers ranging from 2.76e+8 to 6.89e+8 and hartman numbers ranging from 100 to 300. 3.1 influence of nanoparticle concentration the hot side of the thermal bath's enclosure had temperatures of 40 °c, 45 °c, 50 °c, and 55 °c, while the cold side had temperatures of 20 °c, 15 °c, 10 °c, and 5 °c. the fluid's temperature was measured within the cavity, along the cavity's mid-plane, under ha=300, as shown in figure 6. according to the volume concentration of a certain fluid, the temperature for all four thermal bath configurations (the hot-cold thermal bath temperature indicated in the legend) determined which fluid will be used. for any thermal bath arrangement, the value at x = 0 m corresponds to the temperature of the cold wall in the center of the wall. while the value at x = 0.1m corresponds to the temperature of the hot wall in the center of the wall. practical experiments show that the temperature of the nanofluid in the middle of the cube increases as the temperature difference between the two side walls of the enclosure increases. this is because the rotational motion of the fluid increases with increasing temperature differences. therefore, good fluid mixing is achieved, which leads to higher fluid temperatures. it is also noted that the temperature of the nanofluid with the highest concentration beside the hot wall is the highest compared to the other nanofluid sections, while the temperature of it is the lowest beside the cold wall. this is since raising the concentration of nanomaterials improves the thermal conductivity of the fluid, and hence its heat absorption is particularly high at the hot wall. on the contrary, the nanofluid with the highest concentration of nanoparticles has a very high loss of heat when it hits the cold wall. moreover, the addition of cuo particles enhances the buoyancy, and the size of the vortices increases. in addition, the magnetic flux on the sidewalls of the cube attracts nanoparticles. as a result, its temperature rises when it is near a hot wall and falls when it is near a cold wall. that will be discussed in greater detail in the subsequent sections of the research. 98 noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 60 (b) =1% 55-5 50-10 45-15 40-20 t em pe ra tu re ( o c ) x (m) 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 =0.5% 55-5 50-10 45-15 40-20 t em p er at u re ( o c ) x (m) 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 =0.1% 55-5 50-10 45-15 40-20 t em pe ra tu re (o c ) x (m) figure 6. fluid temperature at different cuo volume concentrations. the information below is used to assess how much of the heat that departs from the hot side of the heat exchanger is completely transported through the system. the primary goal of managing the flow rate from the thermal baths is to minimize the disparity as much as possible. the cavity with differentially heated walls transmits all of the heat received at the hot wall to the cold wall in the steady state. therefore, the amount of accessible heat is reduced by altering the flow rate, allowing the nanofluid to efficiently transport the bulk of the heat through the system while lowering other losses and ensuring that the system under investigation is a good approximation of the intended issue. figure 7 depicts the heat transmission at the hot wall. in addition, the average coefficient of heat transfer for hot sides is calculated using heat transfer on the heated side. figure 7 shows that the rate of heat transfer increases as the concentration of nanoparticles in the fluid increases when the vertical wall temperature difference is fixed for all cases. this is because the thermal conductivity of the fluid increases by increasing the concentration of nanoparticles in the fluid. in addition, figure 7 shows that the heat transfer rate has clearly increased as the temperature difference between the hot wall and the cold wall rises because of the fluid velocity acceleration. 20 25 30 35 40 45 50 20 40 60 80 100 120 140 160 180 =0.0% =0.1% =0.5% =1% =1.5% q ( w ) dt (oc) figure 7. heat transfer at the hot wall as a factor of the temperature difference between the hot and cold walls. 3.2 experimental heat transfer coefficient of the nanofluid the influence of various cuo nanoparticles distributed in the base fluid at concentrations of 0.1 %, 0.5 %, 1 %, and 1.5 % on the heat transfer coefficient at ra values ranging from 2.76e+8 to 6.89e+8 was investigated in this section of the study. hartman's number value has been set to 300. the experimental findings indicate that raising the rayleigh number enhances the heat transfer coefficient when the nanofluid concentration and hartman number remain constant. a greater rayleigh number implies a greater flow velocity inside the rectangular container. additionally, scattered nanoparticles in a fluid have been shown to boost its thermal conductivity. as a result, the heat transfer coefficient rises as the flow's velocity and thermal conductivity increase. the greatest improvement is 38.6% at a 1.5% concentration and ra=6.89e+8, and the minimum improvement is 31.5% at a 1.5% concentration and ra=2.76e+8 compared to water. as shown, the heat transfer coefficient rises slightly if the concentration of nanoparticles increases in the case of rayleigh=2.76e+8 but increases significantly as the number of rayleigh grows. in other words, thermal conductivity is the dominant mechanism of heat transfer at low rayleigh numbers, which has a significant effect on the enhancement ratio. when rayleigh is high, the natural convection heat transfer takes precedence over thermal conductivity. (c) (d) (e) noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 99 -0.002 0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 100 150 200 250 300 h ( w /m 2 .k )  ra=2.76e+08 ra=4.13e+08 ra=5.51e+08 ra=6.89e+08 figure 8. effect of ra and nanoparticles concentration of cuo on heat transfer coefficient. 3.3 experimental nusselt number of the nanofluid the nusselt number distributions of cuo nanofluid with various nanoparticle volume fractions are shown in figure 8 at the hot wall. as predicted, the same results established for the behavior of the heat transfer coefficient apply to the behavior of the nu. at the same ra, the average nu for water and nanofluids is compared. as can be seen, the nusselt number and rayleigh number increase as the volume proportion of nanoparticles increases. the maximum improvement is 38.6% at a 1.5% concentration and ra=6.89e+8, and the minimum improvement is 15.7% at a 1.5% concentration and ra=2.76e+8 compared to water. increased nanoparticle volume fraction increases the fluid's overall thermal conductivity and heat transfer. increasing rayleigh number converts heat transfer from conduction to convection, enhancing heat transfer. the presence of a high rayleigh number disrupts the boundary layer and improves natural convection heat transfer. -0.002 0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 15 20 25 30 35 40 45 50 n u  ra=2.76e+08 ra=4.13e+08 ra=5.51e+08 ra=6.89e+08 figure 9. effect of ra and nanoparticle concentration of cuo on the nusselt number. 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 60 (a) ha=100 40-20 45-15 50-10 55-5 t em p er at u re ( o c ) x (m) 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 60 40-20 45-15 50-10 55-5 t em pe ra tu re (o c ) x (m) ha=200(c) 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 60 40-20 45-15 50-10 55-5 t em p er at u re ( o c ) x (m) ha=250(d) 0.00 0.02 0.04 0.06 0.08 0.10 0 10 20 30 40 50 60 40-20 45-15 50-10 55-5 t em p er a tu re ( o c ) x (m) ha=300 (e) figure 10. the influence of various magnetic fields on a nanofluid's heat transfer performance. 100 noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 3.4 experimental heat transfer coefficient of the mhd in this section of the experiment, the impact of varying the magnetic flux values on the hot and cold walls was investigated. the magnetic flux values changed from 0 to 300. in this investigation, cuo/water nanofluid was tested at a volume concentration of 0.015, with rayleigh's number ranging from 2.56e+8 to 6.43e+8. it is clearly seen in figure 10 that the heat transfer coefficient values increase as the ra increases. in addition, the study shows that applying a magnetic field to the walls of a cube containing a nanofluid with two symmetrical walls, one of which is heated and the other is cold, generates two cases of heat transfer, which is either the transfer of heat by convection is dominant or vice versa, the transfer of heat by conduction is dominant. the higher the rayleigh number, the greater the convective heat transfer; conversely, the higher the hartman number, the stronger the heat transfer conduction and the lower the convective heat transfer. this investigation discovered that the heat transfer coefficient increases as the rayleigh number increases, as indicated previously, and the heat transfer coefficient reduces as the hartman number increases. in addition, it can be shown in figure 11 that the heat transfer coefficients at ha=100 and 150 are larger than the heat transfer coefficients at ha= 0. the maximum enhancement is 40.8% at ra= 6.7e+8 and ha=100 compared to water at ha=100 and ra=6.7e+8. as previously stated, the hartman number significantly impacts the pace at which heat transfers between two objects. the existence of lorenzo forces causes the nanoparticles in the fluid to be drawn to the wall. since the low magnetic flux does not greatly restrict the velocity of the fluid, the absorption of heat from the nanoparticle rises as a result. 3.5 the influence of a magnetic field the impacts of various magnetic fields on the heat transfer performance of a nanofluid are only assessed for the 1.5 percent volume concentration scenario because this nanofluid demonstrated the greatest rise in nu when the largest magnetic field was applied. based on the findings in section 4.1, there is reason to anticipate that when the other volume concentration nanofluid is utilized, the heat transfer performance will be considerably more sensitive to the magnetic field, particularly in the enhanced scenario. however, in light of the findings of (yu et al. 2017) [24], who discovered that the stability of fluids with a lower volume concentration is poorer, the nanofluid of choice for this investigation was fluid with a 1.5 percent volume concentration, due to the likelihood of increased settling rates due to the extra magnetic pull on the nanoparticles. the temperature degree measured on the hot side of the enclosure is 55, 50, 45, and 40 °c, while the temperature degree measured on the cold side of the enclosure is 5 °c, 10 °c, 15 °c, and 20 °c. the fluid temperature inside the cavity along the mid-plane as a function of ha=100, 150, 200, 250, and 300 is shown in figure 10. the temperature for each of the four thermal bath configurations (described in the legend as hot-cold thermal bath temperature) utilized for a specific fluid is calculated using the volume concentration of that fluid of 0.015. figure 10 shows that although the fluid temperatures in the centerline of the rectangular enclosure increased as a result of the nanofluid compared with water, as mentioned earlier, the magnetic flux on the walls of the cube lowered the fluid temperatures. it also shows that temperatures decrease with increasing magnetic flux. this can be explained by the fact that the magnetic field generates lorentz forces that inhibit the buoyancy forces caused by the heating of the liquid. lorentz forces are perpendicular to gravitational forces in their behavior. as a result, the movement of nanoparticles reduces the heat transfer from the hot wall to the liquid decreases, and the susceptibility of the cold wall to absorb heat from the hot liquid also decreases. 2.00e+08 3.00e+08 4.00e+08 5.00e+08 6.00e+08 7.00e+08 100 150 200 250 300 350 400 450 500 550 600 ha=0 ha=100 ha=150 ha=200 ha=250 ha=300 h ( w /m 2 .k ) ra figure 11. effect of different ha and ra on heat transfer coefficients. 3.6 experimental nusselt number of the mhd figure 12 shows the change in the nusselt number because of the hartman and riley values change. fortunately, nusselt number values gradually increase as riley increases. the reason for this, as mentioned earlier, is the increase in the coefficient of heat transfer. it is also noted that nusselt number values decrease as hartman numbers increase by more than 150. the maximum enhancement is 28.5% at ra= 6.7e+8 and ha=100 compared to water at ha=100 and ra=6.7e+8. this is due to the fact that heat transfer in these cases is caused by the control of heat transfer by conduction and the decrease of heat transfer by convection, in contrast to the case of hartman numbers values. increasing the intensity of the magnetic flux limits the speed of flow and buoyancy. 2.00e+08 3.00e+08 4.00e+08 5.00e+08 6.00e+08 7.00e+08 10 20 30 40 50 60 70 80 90 100 ha=0 ha=100 ha=150 ha=200 ha=250 ha=300 n u ra figure 12. effect of different ha and ra values on nusselt number 4. conclusion numerical findings can be summarized as follows: noor najem et al. /al-qadisiyah journal for engineering sciences 15 (2022) 094–101 101 1. the addition of cuo particles enhances the buoyancy, and the sizes of the vortices increase. 2. the magnetic flux on the sidewalls of the cube attracts nanoparticles, thereby increasing its temperature at the hot wall and decreasing it at the cold wall. 3. the rate of heat transfer increases as the concentration of 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[22] m. corcione, "empirical correlating equations for predicting the effective thermal conductivity and dynamic viscosity of nanofluids," energy convers. manag., vol. 52, no. 1, pp. 789–793, 2011. article al-qadisiyah journal for engineering sciences 15 (2022) 187–191 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: karim.husain@qu.edu.iq (karim husain) https://doi.org/10.30772/qjes.v15i3.834 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. anatomical scaffold application for the digital rebuilding of human lower jaw defects karim najm husain department of mechanical engineering, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 05 june 2022 received in revised form 05 august 2022 accepted 09 september 2022 keywords: anatomically scaffold geometrical pattern rebuilding, missing part lower jaw a b s t r a c t researchers are making huge efforts in the field of rebuilding the large missing parts of the human lower jaw, and this represents a major challenge in the field of bone engineering based on reconstruction on the basis of human bone implants. this challenge is to create customized designs that fit the physiological, genetic, and anatomical characteristics of each individual patient. designing these implants specifically for each case will definitely improve and reduce the recovery period. in order to achieve an improv ement in the lower jaw surgery process and clinical practice, the required design of a precise three -dimensional engineering scaffold whose external shape resembles the shape of the missing part of a lower jawbone will reduce the appearance of complications during recovery in addition to preserving the teeth to be implanted and meet mechanical as well as aesthetic requirements. the scaffolds that are designed and will be implanted to replace the missing parts of a lower jaw will be subject to great mechanical loads, for this reason, a scaffold that meets the anatomical conditions is designed on the basis of the 3d geometry of patterns be addressed in research. the process of changing the 3d patterns leads to the modification of the mechanical properties of the scaffold. because of its complex structure, will be applying additive manufacturing techniques to manufacture this scaffold. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction a result of exposure the bone (a lower jaw) to major trauma or one of the bone diseases like cancer, fragility, necrosis, etc. maybe leads to the loss of a large part of the bone tissue, which requires the implantation of a scaffold [1,2,3]. the application of accurate engineering models of scaffolds and their implants to rebuild the missing part of the bone is of great importance in current medical uses in the field of reconstruction of a lost large part of bone tissue [4,5]. researchers are making unremitting efforts to improve the available and applicable solutions to reconstruct the missing parts of the lower jawbone and to adapt these solutions each specific pathological condition (individual patient). a number of elements have contributed to accelerating the pace of this research, including the development that has been achieved in the field of information technology, electronics, genetics, regenerative medicine, genetic engineering, and applications of additive manufacturing that contributed and helped in the production of engineering structures with complex shapes [6]. implantation of anatomically shaped scaffolds to reconstruct a missing part of the bone can be considered a standard implant due to its improved ossifying properties, although there are many bone restoration methods that can be used [7]. to complete a successful design process of a scaffold, the application of cad [8,9] software techniques is employed to re-create a similar geometric model to the missing part of the lower jawbone tissue, where 3d precise geometric models of the cell unit are designed that simulate the complex internal structure of the bone tissue and are completely compatible with the most complex external shape of the missing part. the good http://qu.edu.iq/ mailto:karim.husain@qu.edu.iq https://doi.org/10.30772/qjes.v15i3.831 https://doi.org/10.30772/qjes.v15i3.831 http://creativecommons.org/licenses/by/4.0/ 188 karim najm husain/al-qadisiyah journal for engineering sciences 15 (2022) 187–191 permeability of the scaffold is supposed to allow the passage of nutrients, cell proliferation, and migration with an approach that has been presented to design a 3d model scaffold that can be implanted instead of the missing part [10-11]. the necessary mechanical tests will be performed for the purpose of avoiding any failure or defect of fracture that may occur during or after the implantation process. the main purpose of scaffold implantation is to reconstruct the lower jaw, aesthetic, and functional rehabilitation, treatment of associated psychological damage, and acceleration of the complete recovery, and make life better after performing the scaffold implant operation [12-14]. 2. method and material referential geometrical entities(rges) can be curves, points, axes, planes, lines, and other geometrical elements which are considered an important part of the method of anatomically features(maf). performing accurate reverse-engineering modeling of the human lower jaw requires correctly identifying the referential geometrical entities that are generated each defect individually. in each polygonal model of a lower jaw, the anatomical features of the acquired samples are determined and defined in relation to the geometry that is built on the support geometry associated with the ribs, such as curves, spline ...etc. geometric constraints and marks are required when creating the correct lower jaw geometry using the minimum possible basic set of lower jaw elements. planes and lines are elements of the geometric models of a lower jaw, and they represent the ability to form anatomical features on the surface of the model, and they are considered engineering elements that have a great contribution to rebuilding the 3d missing part of a lower jaw. also, anatomical and engineering landmarks can be used to create a threedimensional model of the surface of the missing part of a lower jaw. using the basic modeling approach, the construction of3d model of a scaffold can be designed. fig. 1. shows a set of referential geometrical entities: • a sagittal plane, that passes through a lower jaw body and split it into two equal parts left and right • a vertical plane is a plane that split the lower jaw body into two parts posterior and anterior, bypasses through the body, in the direction of left-right. • a transversal plane (horizontal) is a plane that passes through the lower jaw body parallel to the ground. • a medial line is a line that commonly split the face into two equal and similar parts and passes vertically amidst central incisors. figure 1. the referential geometrical entities illustrated on a lower jaw 3. creating a surface of a lower jaw model to create a model of the surface of the lower jaw, the method of anatomical features is used (maf) [15, 16]. through the application of a cloud points that enables to the determination of the desired polygon pattern by selecting the determined points that achieve the desired purpose together with the curves that have been created for the outer surface. it is assumed that the following sequential steps be followed which enable to obtaining of a precise lower jaw surface model [17,18,19]. • obtaining a computer tomography (cts) scan or a magnetic resonance images (mris) images of the entire a lower jaw in (stl) file format. • use appropriate software (catia in this research). • cleaning photos of impurities and excesses undesirable. • determination referential geometrical entities of the full lower jaw. • the creation of cloud points to the full lower jaw. • exclude unwanted points from the points cloud. • creation of a polygonal model of the lower jaw. • creation of a curve splines. • creation of a sufficient number of surface models for the anatomical sections and assembling all these individual surface models of anatomical sections are into one complete model 4. digital scaffold model for large missing part of a lower jaw to reconstruct the large missing part of the a lower jaw due to its exposure to a major trauma as a result of falling on a hard area, traffic accidents, or due to orthopedic diseases, an action plan must be developed that includes the adoption of various patterns and structures, the application of appropriate procedures and accurate design to create (compose) an engineering model that matches the geometry of the missing part of the a lower jaw and implanting without physical or anatomical obstacles[20-22]. creating the scaffold and implanting it in the place of the missing part of the lower jaw provides the required mechanical support for the new cells generated, which leads to the restoration of the lost bone tissue structure. in this paper, the main component of the scaffold design is the multi-cell unit in a three-dimensional space for the purpose of obtaining a volume pattern that represents the missing part of the lower jaw. there are several models for the design of the cell unit such as a box or circular. in this research, the circular model of the elements of the cell unit was applied, which is called the anatomical scaffold model as shown in fig. 3. to obtain the required scaffold, the scaffold will be modeled by through the circular pattern of the unit cell, which can be manufactured by applying the available additive manufacturing methods techniques that enable the fabrication of complex structures. fig. 4. changing the diameter of the circular cell unit leads to controlling the scaffold density and this is easily done because the design is still software. for example, with decreasing the value of the unit cell diameter, the scaffold density increases (d = 0.25 mm in this research). the dimensions of the elements will be determined by the place value appropriate which corresponds to the l manufacturing dimension of the molten titanium alloy (slm, ebm) or sintered titanium alloys (sls and dmls). fig. 6 shows the spline curves that were created based on the anatomical feature of a lower jaw and its relationship to other anatomical features. the missing part is creat by the application of interpolated spline curves were created using the basic rges(planes) of the human lower jaw, as well as the polygonal model of the missing part of the lower jaw, which was designed based on additive geometry and maf, which applied to model the missing part of the lower jawbone, [13]. in this paper, for the purpose of the creation of the volume of the missing part of the lower jawbone, four curves were selected in addition to the curves of the sections of the ends of two parts of the human lower jawbone. karim najm husain/al-qadisiyah journal for engineering sciences 15 (2022) 187–191 189 figure 2. shown large missing part a lower jaw on the polygonal model figure 3. 3d circular unit cell element figure 4. cylindrical a lattice unit cell diameter figure5. scaffolds patterns of cylindrical unit cell elements a scaffold created to replace the missing portion of the lower jawbone and new bone tissue cells generated will be in desperate need of the support it provides by one spline curve which is going through the gravity center of the profile curves was chosen. if the difference between the implanted scaffold and the external shape of the missing part of a lower jawbone is large, through the growing process, it is recommended to monitor and follow the shape of the bone to protect the surrounding tissue from damage and facilitate and expedite the patient's recovery process. after the implantation process, the lower jawbone will grow by generating new bone cells to fill the volume of the missing part with new bone tissue. it is recommended to monitor the growing process and follow the shape of the bone to protect the surrounding tissue from damage and facilitate and expedite the patient's recovery process, especially if the difference between the implanted scaffold and the external shape of the missing part of the lower jawbone is large. the volume model of the missing part of the lower jawbone was created by the application of the volume multi-section technical features, and it is presented in fig. 7. the application of the missing lower jaw volume model, which is established based on the application of the feature of the multiple volumetric sections of the missing lower jawbone for the purpose of creation of the modified pattern model for the final scaffold shape. the creation of the volumetric model depends on the application of the boolean removal process. the main element in the removal process is the removal coefficient and volume model for the missing part of a lower jawbone, a scaffold pattern. the creation of the volumetric model depends on the application of the boolean removal process. the main element in the removal process is the removal coefficient and volume model for the missing part of a lower jawbone, a scaffold pattern. the 3d pattern of the scaffold to the similarity of the missing part (cells unit elements) can be formed by the implementation of the cutting process on the 3d pattern to match the shape of the missing part of the jawbone of a customized patient, after carrying out all design procedures which mention above fig.8. the scaled spline curves are applied to the creation of the support of the scaffold and its inner structure by creating a supporting shell element. a shell model will be created by the applying of remove boolean operation between inner and outer volumes. this approach of scaled curves is applied to enable variation in shell thickness throughout the missing volume, which can be controlled by a scale factor. in order to sure better blood flow, the shell must have included adequate holes throughout the volume. to guarantee less foreign material will remain in the patient body after the recovery process can use the clean medical net to replace the shell model in medicine as a supporting structure. this assembly will still maintain poor stability, and for the purpose of improving its stability, it will be applied geometry of a customized reconstructive plate model. the customized plate model will be connected to the shell contour and also to the right and left sides of a lower jawbone with sufficient screws. this customized plate can be removed later. the plate shape will be adapted to the shape of the outer surface of the shell and a lower jawbone body figure 6. creation of spline curves of the jawbone missing part 190 karim najm husain/al-qadisiyah journal for engineering sciences 15 (2022) 187–191 figure 7. the volume model of the missing part of the lower jawbone figure 8. the creation of a cylindrical scaffold model from the unit cell figure 9. a shell volume model (supporting structure) together with a polygonal model of a lower jaw and the scaffold model figure 10. assembly of the reconstructive plate, shell support structure, and scaffold models 5. new design approach in order to reduce the use of foreign material in the patient body, a new design strategy based on a lattice “rudder” structure is introduced. they can be positioned where is appropriate to support the scaffold is established. 5.1 rudder design this approach presumes use of tubular form, which goes throughout the gravity centers of cross section spline curves and gives support for the surrounding lattice structure. this scaffold design, named rudder (in axial sections, the scaffold design reassembles the ship's rudder), is presented in fig.11. as can be seen from the image, the structure consists of radial and axial lattices. also, only one part of the whole structure is presented, but the design intent is clear. radial lattices are reared near the center axis of tubular form, but, there are more of them if the distance from the center is increased. axial lattices are going from one side of the missing part to the other side. increasing the number of lattices in both radial and axial directions, lead to an improved possibility withstand the external forces and stresses that can affect the scaffold in both radial and axial directions without fracture. figure 11. rudder scaffold structure 5. conclusion it is expected that the design of an anatomical shaped lattice structure of the supporting scaffold will be the ideal solution in the applications of reconstructing the missing part of the bone. the application of (asls) gives multiple choices for surgeons in choosing the appropriate method for stabilizing bone fractures when compared to traditional methods of stabilization. the application of (asls) is expected to provide a suitable environment that increases and accelerates the process of generating new bone tissue cells. this claim requires the implementation of the anatomical scaffold application procedure and proper fixation to the frame in the designated place. the manufacture of (asls) requires the use of additive manufacturing(am)techniques. studies in this field also indicate the need to search for materials that can be used in the manufacture of these complex structures(asls) that are biocompatible with the patient’s tissues and have the ability to biodegrade inside patient tissue after implantation without causing any complications or damage. in this section the authors can refer any specific grant from any agencies references [1] john c. koshy, evan m. feldman, chuma j. chike-obi, and jamal m. bullocks, pearls of mandibular 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[22] karim husain, mohammed rashid, nikola vitković, jelena mitić, jelena milovanović, miloš stojković, geometrical models of mandible fracture and plate implant, facta universitatis, series: mechanical, 2018/12/13engineeringhttps://doi.org/10.22190/fume170710028h [23] gomez, c., shokoufandeh, a., sun, w., 2007, unit-cell based design and modeling in tissue engineering applications, computer-aided design & applications, 4(5), pp. 649 https://doi.org/10.17559/tv-20181009193111 http://www.gdzjg.org/index.php/jol/index article al-qadisiyah journal for engineering sciences 13 (2020) 207-214 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: shymmaakram35@mtu.edu.iq (shymaa akram alrubaie) https://doi.org/10.30772/qjes.v13i3.658 2411-7773/© 2020 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. support vector machine (svm) for colorization the grayscale image shymaa akram alrubaie a*, israa mohammed hassoonb a middle technical university, continuous education center, baghdad-iraq b al-mustansiriyah university, college of science, mathematics science, baghdad-iraq a r t i c l e i n f o article history: received 05 june 2020 received in revised form 15 july 2020 accepted 20 july 2020 keywords: support vector machine (svm) discrete wavelet transform (dwt) haar-dwt red green blue color system (rgb) a b s t r a c t recently, there have been several automatic approaches to color grayscale images, which depend on the internal features of the grayscale images. there are several scales which are considered as a prominent key to extract the corresponding chromatic value of the gray level. in this aspect, colorizing methods that rely on automatic algorithms are still under investigation, especially after the development of neural networks used to recognize the features of images. this paper develops a new model to obtain a color image from an original grayscale image through the use of the support vector machine to recognize the features of grayscale images which are extracted from two stages: the first stage is haar discrete wavelets transform used to configure the vector that combines with six of statistical measurements: (mean, variance, skewness, kurtosis, energy and standard deviation) extracts from the grayscales image in the second stage. after the support vector machine recognition has been done, the colorization process uses the result of support vector machine to recover the color to greyscale images by using ycbcr color system then it converts the color to default color system (rgb) to be more clear. the proposed model will be able to move away from relying on the user to identify the source image which matches in color levels and it exceeds the network determinants of image types with similar color levels. in addition, support vector machine is considered to be more reliable than neural networks in classification algorithms. the model performance is evaluated by using the root mean squared error (rmse) in measuring the success of the assumed modal of matching the coloring (resulting) images and the original color images. so, a reality-related result has been obtained at a good rate for all the tested images. this model has proved to be successful in the process of recognizing the chromatic values of greyscale images then retrieving it. it takes less time complexity in trained data, and it isn’t complex in working. © 2020 university of al-qadisiyah. all rights reserved. 1. introduction the colorization process can be done automatically by using a computer to recover the color of black-and-white and grayscale images or films. there is a wide use of this technique in image processing and it can be used scientifically to recover the color of black-and-white films or to restore old color films. currently, most of the images that need to be colored are grayscales images and this makes them a reliable source of interest for researchers in this field. there are multi-processes for colorizing images http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 208 shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 and this depends on different methods and each process requires time and technical accuracy to restore the colors suitable for grayscale images casaca et al. [1], colorizing the grayscale image add three-dimensional (rgb) pixel values to the image that has only one dimension (luminance or intensity), while there are multi hue or saturation for the same luminance value that determines the color. for this reason, the challenges of colorizing grayscale images have appeared while no inherently “correct” solution to take into account. usually, human vision plays an important role in the colorization method and the process of the colorization will manually depend on human vision kumar et al. [2]. in some domains, colorizing grayscale image could be automatic, the automatic colorization is very beneficial as it decreases the time and increases accuracy. this is because it depends on information that is collected from an image. several techniques have been used for colorization, some of the methods used reference images that have similar features to the target grayscale image to transfer its colors futschik et al. [3]. occasionally, there are completely automated solutions for colorizing images, one of them is performed by artificial neural networks. many research papers used multi kinds of artificial neural networks ann, these techniques make the automate colorization easier and shorter processing time, and it can be applied on a larger scale an et al. [4]. with the development of ann, the process has to gain more attention as a performed issue for perfect visual realization of artificial intelligence. it is represented as an object recognition process. the coloring process passes through several stages to reach true color image futschik et al. [3]. in this paper, we propose an automatic image colorization algorithm using the support vector machine to recognize the features of grayscale images, svm used to recognize the features of grayscale images, its work depends on the principle of structural risk minimization from statistical learning theory. svm represents a learning algorithm and is widely used in the classification of the objects in images awad et al. [5]. this paper is organized as follows: section 2 displays related work, section 3 presents methodology, section 4 illustrates experimental results, while performance measurement in section 5, while discussions & comparisons explained in section 6, conclusions are presented in section 7, acknowledgments shown in section 8, lastly references appear. 2. related work many studies have attempted to treat the colorization process for the grayscale images to get the most appropriate results. kumar et al. [2] , in this texture features, have dealt with information between the images. five statistical measurements were used as texture features that were extracted from the correlation matrix of the images which are: energy, entropy, homogeneity, contrast, and correlation. zhang et al. [6] depended on an easy premise so that in test time, a feed-forward cnn was trained on over a million color images. the algorithm was evaluated by utilizing a "colorization turing test,". the participants were asked to choose between the output color image and the true color image. this algorithm was successful by a higher rate in deceit 32% humans of the trials. a novel approach to colorize grayscale images that allows user intervention presented by wallace casaca et al. [1], this methodology makes use of multidimensional projection to map high-dimensional data to a visual space. a user can manipulate projected data in the visual space to improve further clusters and thus the colorization result, the easy use of interactive tools while still being flexible enough to enable local color modification. the approach was proved to be effective through experiment, set of examples, and comparisons. matías richart et al. [7] depended on training a simple classifier using back propagation that training over a set of colors and corresponding grayscale images. each pixel depends on the gray level of the pixels surrounding it to predict the color of it. self-organizing maps used to reduce the colors so the predictor domain will be kept small, this reduction process of chroma values with enough variation can generate good results for all colors in the training set. a convolutional-neuralnetwork cnn system is built by jeff hwang et al. [8] to colorize the black and white image without direct human assistance. the classificationgenerates model to colorize images that are more aesthetically pleasing than those created by the baseline regression-based model. thus, this shows the efficiency of the method and its future development for better work. domonkos varga, et al. [9] presents an automatic approach that can produce reality color images from an input grayscale image. the method employs deep learning techniques depend on vgg-16 and a two-stage of convolutional neural network (cnn) that predicts the channels of color. in this method, there was no human intervention in the resulting data, rather it was a fully automatic method, the results measured by found that quaternion structural similarity (qssim) that gives a good evaluation for the quality of colorization. jiancheng an et al. [4] developed the work of domonkos [9] by using the loss of cross entropy that is given a good a plausible colorization. therefore, the method enhanced the colorization process. joharia, et al [10] in this work, states that the colorization process consists of two stages; the first stage depends on an auto-encoder colorization network to determine the similarity of the images and produce an initial colored image. the second stage consists of several specialist networks, whose tasks are improving the quality of the initial colored image and producing real-looking, plausible images. the method is compared with several previous methods in order to demonstrate the capability of the proposed method. nomenclature b bias of network pαβ original image cnn convolutional-neural-network rmse root mean squared error hh diagonal-frequency components (sub image) in haar-dwt ann artificial neural network hl horizontal-frequency components (sub image) in haar-dwt n number of pixels in image k kernel function p α̃β test image (image after color process) lh vertical-frequency components (sub image) in haar-dwt ll low-frequency components (sub image) in haar-dwt greek symbols m number of image σ standard deviation rbf gaussian radial basis function αi weights si support vectors α error rate u train vector αβ de-correlated 2-channel of color space x test vector ε constant value belongs to [0; 1]. ycbcr color space consists of a three channels y, cb, and cr. so y channel shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 209 3. methodology the proposed model is based on svm neural network to recognize the colors of the grayscale images, this model works by input the extracted features from the grayscale images as inputs. svm is training by multi color images, these images are converted to grayscale then the features were extraction from them which are used to train svm. the trained svm will be used to recognize the features of grayscale images and classify it to any of the trainer images in a similar way, then the process of recovering color will be done to get the appropriate colors of it depending on svm recognition. the success of svm depends on the type of entering features, these features are extracted by the use of dual stages which they are haardwt and six of statistical measurements. by these two stages, one vector obtained to be the input of training svm, these features are proved to be appropriate in svm usage, the model is illustrated as following block diagram in fig. 1: figure 1 block diagram of the proposed model 3.1. extract features the important characteristics (features) will be extracted from the grayscale image. so, to reduce the non-useful information from the image, the features are extracted by two stages: 3.1.1. haar-dwt the first stage of feature extraction is haar-dwt. it is used to find good features, haar-dwt represents the simplest kind of dwt in addition to its speed and easy processing [11] [12]. the haar-dwt, like other wavelet transforms, consists of a discrete signal into two sub-signals. four subimages (ll, lh, hl, and hh) decomposed the plain image from the twodimensional wavelet transform. these sub-images are: the low-frequency signal and high frequency signal ahadpour et al. [13]. well, the lowfrequency signal is the most important part, since the high frequency part of an “additive” impact, for more details about haar-dwt see [11] [12]. haar-dwt is decomposed to four levels, in each level the low-frequency signal(ll) is decomposed to be the input to the next level of the haardwt, so the ll image can be decomposed to four new sub-images which make a tree of sub-images, then the four decomposition of ll sub-image can be converted to be vector of this stage. as seen in fig. 1 3.1.2. statistical measurements the second stage is used to increase the strength of the resulting vector of haar-dwt. in this stage, six of statistical measurements were used, which are: mean, variance, skewness, kurtosis, energy and standard deviation sachdeva et al. [14]. these statistical measurements are considered used more to extract special features from the images, so the statistical measurements are extracted directly from the image, more details about these statistical measurements found in [14] [15]. the extracted statistical measurements are added to the haar-dwt vector to compose the final vector, this vector acts as an input to the next step. see fig. 1 3.2. support vector machine support vector machine (svm) represents a supervised learning method which can be able to classify objects by employing the machine learning theory to increase prediction accuracy with avoiding over-load of data sakthivel et al. [16]. svm depends on the concepts of structural risk minimization from statistical learning theory; it utilizes a learning algorithm in feature space to train the features with optimization theory that performs a bias learning theory. the objective of the svm is to find the highest minimum distance between any two points of data quickly sakthivel et al. [16]. svm locates the closest data vectors called support vectors (sv) to the decision boundary in the training set, so it depends on these vectors to classify a given new test vector xia et al. [17]. svm can be handled two problems of input space: linear and nonlinear awad et al. [5], the default formulation of svm is used to classifier linear problem while the nonlinear problem of input space will be separable, therefore the kernel function can be used to transform the data to a higher-dimensional space, which referred to as "kernel space". in the kernel space, the classification task will be done while in the input space in a high-order separating hypersurface will be solved. awad et al. [5].in nonlinear svm, the kernel k is represented as a hyperplane in a feature space induced by its "the kernel is defined as a dot product in that space"). therefore, the hypothesis space is defined as "a set of "hyperplanes" in the feature space induced by k", thus svm depends on two important things: the hypothesis spaces and the kernel function. there are many kernel function which can be used with svm, for example: linear kernel, polynomial function, gaussian radial basis function (rbf), and laplacian radial basis function. the kernel selection that is used in svm is based on the data specifics awad et al. [5]. in this proposed work, nonlinear svm will be used to classify the input data features with "gaussian radial basis function kernel rbf". svm with rbf-kernel is considered to be the best solution for the classification 210 shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 process [18]. the trained svm function to identify the support vectors si which has been used as an optimization method, according to equation (1) rahayu et al. [19]: 𝑐 = ∑ 𝛼𝑖 𝑘(𝑖 𝑠𝑖, 𝑥) + 𝑏 (1) where i is the class number, k is a kernel function. αi is a weight, and b represents bias that are used to classify vectors x. if c ≥ 0, x is classified as a member of the first group, otherwise it is classified as a member of the second group. , "gaussian radial basis function kernel rbf" is the kernel function of trained svm that uses to map the training data into kernel space the value of it depends on a scaling factor (σ), "gaussian radial basis function kernel rbf" represented as the equation (2) [11] 𝐾(𝑥, 𝑢) = exp [ ‖𝑥−𝑢‖2 𝜎2 ] (2) where x is the test vector, u is the train vector, and σ is the represented as a scaling factor (standard deviation). 3.3. color recovering the process of converting the color from the source (color image) to a target (grayscale image) needs matching luminance and texture features between the images. in this process, two stages are followed: first, ycbcr color system will be used to recover colors, ycbcr represents the decorrelated color space that is used for colorization process. ycbcr color space also consists of three channels y, cb, and cr. so y channel: it is an achromatic luminance channel, cb represents the chromatic channel of difference between blue component and a reference value, finally cr represents the chromatic channel of difference between red components and a reference value kumar et al. [2] while a grayscale image represents one channel (luminance channels) which it is matched with channels of colors images. after the target image matches a source image, color information is transferred between the two images of pixels while retaining the value of the original lighting. for more details about ycbcr color system, see kumar et al. [2]. in the second stage, the ycbcr color image is converted from the ycbcr color system to the default color system (rgb) which is a compound of three chromatic channels (red, green, blue), in this method, the color image will be more clear and the colors are considered nearest to the reality. 4. experimental results in this paper, svm training with 20 images, these images are selected to be different in size, type format (bmp, and jpg), and resolution. the diversity in selecting images has proved that svm is more reliable and more recognized to test different images. training images have been selected on five color spectra: 5 images with chromatic spectrum for orange gradients, 3 images with chromatic spectrum for blue gradient, 3 images with chromatic spectrum of red and syphilis, 4 with chromatic spectrum for green gradients, and 5 images with chromatic spectrum overlapping blue and green. these images are subject to the unification of each size in order to obtain a vector of equal length for all images when extracted the vector using the first stage (haar-dwt) in extract features process. thus, the resizing of an image is to be about 160*250 then the image is converted to be the grayscale image, this stage produces a vector with 160 long, addition to this vector the vector obtained from the second stage of the extract features process to obtain a vector at 166 long for each image. svm used gaussian radial basis "rbf" as a function kernel with a 1 scaling factor (σ) for training with these vectors to classify the test images which are matching color images that training with svm. the training images showed in fig. 2. then svm was tested with 40 images that are different from the training images. the strength of the svm was detected in recognizing the color spectra of images according to the characteristics (features) that were prepared for them. the tested image represents a grayscale image, then the features which were extracted from it would be the inputs to svm to recognize the nearest matching image. the colors were taken from the matching image and turned into the new (tested) image by the use of ycyr color system method then they are converted to rgb color system. some of the results of the tested images showed in fig. 3. 1 2 3 4 5 6 7 8 shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 211 9 10 11 12 13 14 15 16 17 18 19 20 figure 2original color images used for training svm (20 images) a b c d a b c d a b c d 212 shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 a b c d a b c d a b c d a b c d a b c d a b c d a b c d figure 3(a) original color images, (b) grayscale images, (c) rgb color images, (d) the matching training image shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 213 5. performance measurement in this paper, the root mean squared error (rmse) is used to measure the success of the assumed method of matching the coloring (resulting) images and the original color images, this scale is used to measure the quality of images and it is very commonly used and makes an excellent general purpose error metric for numerical predictions rajashree et al. [20]. it measured rmse between the original color image and the result color image. it represents the percentage of error measurement of the matching between color images and original images. the formula of rmse is in (3) futschik et al. [3] 𝑅𝑀𝑆𝐸(𝑃𝛼𝛽 , �̃�𝛼𝛽 ) = 1 𝐼∗𝑁 ∑ ∑ √‖𝑃 𝛼𝛽 𝑖,𝑗 − �̃� 𝛼𝛽 𝑖,𝑗 ‖ 2 𝑁 𝑗=1 𝑀 𝑖=1 (3) where m is the number of images and n is the number of pixels in an image. the error α is calculated in de-correlated 2-channel αβ color space, as in equation (4) [3] 𝛼𝛽 = 𝐵− 1 2 (𝑅+𝐺) 𝐿+𝜀 (4) where l = (r+g+b /3 ), ε = 0:0001 and r,g,b channels are normalized ε [0; 1]. the result of the evaluation and the efficiency of the proposed model for the colorization images see in (table 1) that appears rmse of the proposed model. table 1the results of rmse of the proposed method no. rmse no. rmse 1 55.80571 21 57.37862 2 103.7273 22 68.17108 3 61.61202 23 41.25144 4 42.57201 24 88.7847 5 44.79534 25 74.59644 6 81.40136 26 65.05274 7 68.11881 27 97.97648 8 85.64872 28 91.2866 9 117.5906 29 72.82589 10 129.8653 30 77.4869 11 72.79234 31 37.13677 12 167.9442 32 54.89998 13 50.31454 33 63.6623 14 23.27662 34 77.80699 15 30.54028 35 105.5327 16 97.76456 36 109.4407 17 84.39768 37 71.15946 18 91.47904 38 70.44696 19 84.6228 39 43.30157 20 102.5789 40 49.30605 6. discussions & comparisons the colorization process depends on two parameters to obtain the final evaluation: are the results good or not? first parameter can be deduced form the results of rmse of the proposed model is presented in table 1, the analysis of the one that is presented in chart in fig 4. it can be noted from these results that most of the tested images in the svm did not exceed the error rate of 100 although the svm trained on multi spectra images. also, from these results showed that only 7 images exceeded the 100 error rate. second parameter can be deduced if we take a visual scale of view of the image note that the results color images from the proposed model are acceptable by viewer and not far from the original color of images. by relying on these two parameters for evaluation, it becomes clear for us that the model works well and has good results. so, a reality-related result were obtained at a good rate for all the tested images. in addition, the method deviated of manual comparison to an automatic method and a void the troubles of artificial neural network ann. by making a comparison with previous states of art colorization models: the models of: zhang et al. [6], jeff hwang et al. [8], and domonkos varga, et al. [9] in all these models convolutional neural networks (cnn) would be used, cnn which considered one of artificial neural network ann. while joharia, et al [10] used the ann by two stages in their work, and this increases the time complexity and made the performance more expensive. ann suffers from many problems and is regarded as a less performance technique compared with svm nitze et al. [18], svm distinguished by multi options that are not found in ann [5] [18]. svm avoids the double curse of dimensionality and overfitting, therefore it can exceed a problem of classical multifocal minima. overfitting in machine learning model occurs when all training data is aimed to be a zero, that is more likely to occur with machine learning approaches by minimizing the structural risk rather than the empirical risk, as in the case of ann "the training metrics depend on variants of the sum of squares error" [5]. the classification accuracy is obtained by the svm classification algorithm is higher than ann classification algorithms kumar et al. [21]. the complexity of svm is automatically determined by selecting the number of supported vectors, while in ann the complexity is determined by limiting the feature set, and this made control model complexity of svm less than ann awad et al. [5]. svm represents the best solution for the different classification, svm has a higher classification performance, faster calculation time, and more robustness compared to ann nitze et al. [18]. figure 4rmse of the proposed method 0 50 100 150 200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 rmse… 214 shymaa akram alrubaie , israa mohammed hassoon /al-qadisiyah journal for engineering sciences 13 (2020) 207-214 7. conclusion this paper developed an automatic technique to colorize grayscale images by using svm as a recognition technique for the most similar color images to convert its colors to target grayscale images. the success of svm recognition is based on the kind of extracted features which are regarded as inputs to svm. features were extracted by two stages: the first stage is haar-dwt that product vector was combined with the vector product from the second stage which is; six of statistical measurements: mean, variance, skewness, kurtosis, energy, and standard deviation. the final vector of features extraction process is represented as an input to svm in training and testing phases. svm trained on multi images with various color spectra to be able to recognize various colors images. the performance of this model was evaluated by using root mean square error (rmse) measure, the obtained results of this model would be good depending on the values of rmse and the visual scale of view of the image by the viewers. svm trained with 'gaussian radial basis rbf" as function kernel and this made the classification more efficient in comparison with ann, svm distinguished by it is avoid the troubles of ann, also. it has a higher performance and less training time in classification algorithms. acknowledgments we would like to thank the universities that facilitated the task of researchers contributing to the research and affiliated to it, which are: middle technical university (www.mtu.edu.iq), al-mustansiriyah university (www.uomustansiriyah.edu.iq), for their support to the present study. references [1] casaca, w., gomez-nieto, e., ferreira, c. o., tavares, g., pagliosa, p., paulovich, f., ... & paiva, a.,, “colorization by multidimensional projection,” in 25th sibgrapi conference on graphics, patterns and images, 2012. [2] kumar, smriti, and deepak singh, “colorization of gray scale images in ycbcr color space using texture extraction and luminance mapping,” vol. 4, no. 5, pp. 27-32, 2012. [3] futschik, david, “colorization of black-and-white images using deep neural networks,” 2018. [4] an, jiancheng, kpeyiton koffi gagnon, qingnan shi, hongwei xie, and rui cao., “image colorization with convolutional neural networks.,” in in 2019 12th international congress on image and signal processing, biomedical engineering and informatics (cisp-bmei),, 2019. [5] awad, mariette, and rahul khanna, efficient learning machines: theories, concepts, and applications for engineers and system designers, springer nature, 2015. [6] zhang, richard, phillip isola, and alexei a. efros, “colorful image colorization,” in european conference on computer vision, 2016. [7] richart, matías, jorge visca, and javier baliosian, “image colorization with neural networks,” pp. 55-60, 2017. 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[13] ahadpour, sodeif, and yaser sadra., “chaotic trigonometric haar wavelet with focus on image encryption.,” journal of discrete mathematical sciences and cryptography, vol. 20, no. 5, pp. 1217-1239., 2017. [14] sachdeva, jainy, vinod kumar, indra gupta, niranjan khandelwal, and chirag kamal ahuja, “segmentation, feature extraction, and multiclass brain tumor classification,” no. 26, p. 1141–1150, 2013. [15] kumar, vijay, and priyanka gupta, “importance of statistical measures in digital image processing,” vol. 2, no. 8, pp. 56-62, 2012. [16] sakthivel, k., r. nallusamy, and c. kavitha, “color image segmentation using svm pixel classification image,” vol. 8, no. 10, pp. 1919-1925, 2015. [17] xia, tian, “support vector machine based educational resources classification,” vol. 6, no. 11, 2016. [18] nitze, i., u. schulthess, and h. asche, “"comparison of machine learning algorithms random forest, artificial neural network and support vector machine to maximum likelihood for supervised crop type classification.,” in " proc. of the 4th geobia 35 , 2012. [19] rahayu, m. s., a. lawi, and s. a. thamrin., “"the comparison multiclass classification using support vector machine.,” in proceeding of international conference on mathematics, statistics, computer science and mathematics education (icmscsme), 2015. [20] rajashree, nambiar p.a, usha desaib, and vibha b. shettyc, “medical image fusion analysis using curvelet transform,” in conf. on adv. in comp., comm., and inf. sci., 2014. [21] kumar, pradeep, dileep kumar gupta, varun narayan mishra, and rajendra prasad., “comparison of support vector machine, artificial neural network, and spectral angle mapper algorithms for crop classification using liss iv data.,” international journal of remote sensing, vol. 36, no. 6, pp. 1604-1617., 2015. article al-qadisiyah journal for engineering sciences 15 (2022) 023–031 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address:eng.chem.20.post.18@qu.edu.iq (abdulla y. ghjair ) https://doi.org/10.30772/qjes.v15i1.809 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. removal of chemical oxygen demand (cod) from hospital wastewater by electro fenton process using graphite–graphite electrochemical system abdulla y. ghjair a ali h. abbar b adepartment of chemical engineering, university of al-qadisiyah, iraq bbiochemical engineering department, al-khwarizmi college of engineering, university of baghdad, baghdad, iraq a r t i c l e i n f o article history: received 15 april 2022 received in revised form 20 may 2022 accepted 21 june 2022 keywords: cod removal electro-fenton porous graphite response surface methodology hospital wastewater a b s t r a c t removal of cod from hospital wastewater generated from aldiwaniyah hospital located in iraq was achieved using graphite–graphite electro-fenton (ef) system. the effect of various operational parameters on the cod removal efficiency was investigated based on response surface methodology (rsm). optimal conditions were current density of 20ma/cm2, feso4 concentration of 0.697 mm and time of 48.687 min. at these conditions cod elimination efficiency of 97.964 % was achieved at a specific energy consumption of 10.78 kwh/kg. the results indicated that time had the least effect on the cod removal efficiency, while the impact of current density had the greatest effect, followed by the feso4 concentration. the adequacy of the model equation was confirmed by its high r2 value (99.62%). the present study shows that graphite– graphite ef system was an efficient tool for removing of cod from hospital wastewaters. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction medical wastewater contains a large number of macro and micro-pollutants with a wide range of concentrations such as microorganisms, toxic chemicals, antibiotics, and radioactive elements coming from laboratories, research units, operating rooms, and polyclinics [1]. recently, the issue of wastewater containing drug residues and their derivatives has taken on a new importance. numerous studies have been conducted and revealed the detrimental effects of pharmaceutical pollutants on various components of the environment. [2]. appropriately, scientists are attempting to develop a method of disinfecting wastewater that is successful and meets the standards for practically total removal of contaminants. the latter is because even a trace amount of a medical pollutant has a detrimental effect on the environment's elements [3]. many conventional techniques of hospital wastewaters (hwws) treatment are used such as biological and physiochemical processes [4, 5]. nevertheless, these methods have not the ability to treatment hwws perfectly because of the composition and nature of these effluents. it was found that the biological treatment process suffered from many problems in the treatment of hwws due to the adverse effects of the contaminants on the community of organisms used in the biological treatment [6]. among advanced techniques, advanced oxidation processes (aops), as identified for the first time by glaze et al. 1987[7], represent potential technology. these techniques are generated by means of strong oxidants in place, primarily radicals’ hydroxyl (ho°), the second most potent oxidizing species (e° = 2.80 v/she), capable of oxidizing any organic pollutant non-selectively up to the point of mineralization (conversion to carbon dioxide and h2o) (reactions 1α and 1𝛽). ho °might well be created using a variety of activation mechanisms, including chemical (fenton reaction), photochemical reactions (photolysis by ultraviolet light, photocatalysis on a heterogeneous scale, and photofenton), sonochemistry, and electro-fenton-reaction. [8-10]. 𝐻𝑂° + 𝑂𝑟𝑔𝑎𝑛𝑖𝑐 𝑝𝑜𝑙𝑙𝑢𝑡𝑎𝑛𝑡 → 𝑃𝑟𝑖𝑚𝑎𝑟𝑦 𝑖𝑛𝑡𝑒𝑟𝑚𝑒𝑑𝑖𝑎𝑡𝑒𝑠 (1α) http://qu.edu.iq/ mailto:eng.chem.20.post.18@qu.edu.iq https://doi.org/10.30772/qjes.v15i1.809 http://creativecommons.org/licenses/by/4.0/ 24 abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 𝑃𝑟𝑖𝑚𝑎𝑟𝑦 𝑖𝑛𝑡𝑒𝑟𝑚𝑒𝑑𝑖𝑎𝑡𝑒𝑠 + 𝐻𝑂° → 𝐶𝑂2 + 𝐻2𝑂 + 𝑖𝑛𝑜𝑟𝑔𝑎𝑛𝑖𝑐 𝑖𝑜𝑛𝑠 (1β) the most modern aops are electrochemical advanced oxidation processes (eaops). they have been created as a non-toxic, environmentally friendly, and cost-effective method of destroying organic compounds in water. [1113]. the electrochemical oxidation (or anodic oxidation) and electrofenton (ef) processes are the most widely used eaops [8, 14, 15]. the chemical synthesis of oh° is commonly accomplished using the fenton reaction (2), which utilizes a combination of h2o2 and a soluble ferrous iron salt, dubbed "fenton's reagent." [8,9]: 𝐻2𝑂2 + 𝐹𝑒 +2 → 𝐹𝑒 +3 + 𝑂𝐻− + 𝐻𝑂° (2) actually, h.j.h. fenton discovered an increase in the oxidation power of hydrogen peroxide in the presence of (fe +2) at the end of the nineteenth century.[16]. after 4 decades, wise and haber [17] established the reaction's dynamics and mechanism, establishing the explanation for the increase in oxidation efficiency caused by the production of ho° from fenton's reagent via processes (1α) and (1β). the fenton reaction is an easy method of producing ho°. furthermore, the method requires a large volume of reagent to generate sufficient oh°. this has economic implications additionally to the production of sludge ferric that requires additional processing. additionally, increased agent concentrations increase sludge processes (3) and (4), resulting in decreased effectiveness: 𝐻𝑂° + 𝐻2𝑂2 → 𝐻2𝑂 + 𝐻𝑂2 ° (3) 𝐻𝑂° + 𝐹𝑒 +2 → 𝐹𝑒+3 + 𝑂𝐻− (4) these reactions are extremely damaging because they consume reagents and deplete ho°. as a result, the decrease in mineralization efficiency results in the development of potentially hazardous oxidation reaction intermediates. [18]. to eliminate these interactions, it is necessary to carefully manage the amount of fenton's reagent .the optimum ph for ef is taken as 3. ph value higher than 3 leads to decrease ef oxidation efficiency due to the formation of low active fe (oh)3which has a lower tendency to react with h2o2 while a ph value lower than 3 generates less hydroxyl radicals and increases scavenging effect of h+ and hydroxyl radicals [19]. few works have been published which confirmed suggested graphite can be utilized as both electrodes in the ef process. [20]. nidheesh et al [21] reported that graphite–graphite ef system has been demonstrated to be an effective electrolytic system for the dyes removal [22-24] and salicylic acid [25] from aqueous solution. the advantage of application graphite–graphite ef process as reported by nidheesh et al [22] is that using graphite–graphite ef system would enhance the efficiency of the system as a result of forming graphite layer on the cathode from anode particles with no effecting on the homogeneity of the system. the aim of present work is to treat hospital wastewater generated from al diwaniyah hospital in iraq using an electrochemical cell composed of porous graphite plates as cathode and anode materials. no such research had been conducted in the literatures. on the other hand, this work investigates the feasibility of ef technology in removal of cod from hospital wastewater where hydrogen peroxide is generated in-situ at porous graphite cathode and fe+2 is added externally. the efficiency of cod removal was evaluated using constant-current mode of operation which is the most preferable mode for industrial scale-up. the impacts of three operating parameters namely applied current density, fe+2concentration, and time on the removal of cod from hospital effluent were investigated and optimized using box-behnken design (bbd) base on the response surface methodology (rsm). 2. experimental work as a case study, 30l of hospital wastewater was collected from sewage system of the general diwaniyah hospital (located at aldiwaniyah city in iraq) before mixing with the domestic wastewater of the city. table 1 shows the properties of the hospital wastewater. this hospital sewage was kept at 4 ⁰c during the period of the experimental program and the required sample (0.25 l) for each experiment was taken from this vessel before the operation. table 1. characteristics of wastewater from the sewage system at aldiwaniyah hospital variable value cod 780 (mg/l) ph 7 (mg/l) t.d.s 1130 (ppm) cl1.6 (g/l) so4-2 0.4 (g/l) turbidity 11.2 (ntu) conductivity 2.29 (ms/cm) any chemicals utilized in this experiment were of analytical degree. na2 so4.10h2o (purity 99.0%, pellets, sigma-aldrich), feso4. 7h2o (purity 99.5%, pellets, sigma-aldrich), h2so4 (98% w/w, sigma-aldrich), and naoh (purity 99%, pellets, sigma-aldrich) were used in the electrofenton reaction. every experiment was performed in a batch manner with the aid of a cylindrical perspex reactor provided with a cover. it has an internal diameter of 89 mm, a length of 80 mm, and a thickness of 5 mm (fig. 1). the working volume of the reactor was approximately 0.25 l. the reactor cover was a square plate with 160 mm on the outside length and 10 mm on the thickness. three holes with inside diameter of 15mm were made in the cover of reactor for inserting probes of conductivity meter, ph-meter, and sampling taking out. a further hole of 10mm for air distribution tube was made on the cover as well as two slots for inserting the electrodes. the anode and cathode were made of porous graphite. each one of two electrodes has dimensions of 53 mm wide, thickness of 4 mm, and length of 85 mm. the distance between anode and cathode was fixed at 2.0 cm. porous graphite was provided from tokai carbon co., ltd. as arc furnace. it has a surface area of approximately 0.892 m2/g measured based on iso9277-2010 method at petroleum r &d center, ministry of oil in iraq using bet surface area analyzer model no. qsurf9600, thermo finnegan co. usa. an air flow meter (0-5l/min, china) combined with air pump (modelaco-208,45w, china) were used to supply the air to the reactor. the reactor and its cover were covered by aluminum foil to prevent the effect of light penetration hence dark conditions for the fenton reaction was maintained. each experiment was carried out at a temperature of 25∓ 2 °c using a hot plate magnetic stirrer (model number mr hei-standard, heidolph) at a rotation speed of 250 rpm. the electrolyte ph was measured using a smart ph meter “hnna equipment inc.ph211, romania”, ph was changed using 0.1 m sodium hydroxide or 0.1m sulfuric acid solutions. constant current was supplied via a dc power supply type (uni-t, utp3315tflii, china). at the beginning of each run, 0.25l of wastewater was put into the reactor, then its ph was adjusted to 4 to make iron species soluble. the required amount of feso4. 7h2o was added with continuous stirring for 20 minutes before adjusting the ph to the required value. 0.05m of na 2so4 was added as a supporting electrolyte to increase the conductivity to the suitable level. abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 25 figure 1. the electro-fenton system: 1) reactor, 2) aluminum foil, 3) conductivity and ph-meter, 4) hot plate magnetic stirrer ,5) air pump, 6) power supply ,7) ammeter ,8) volt meter,9) anode and cathode (porous graphite),10) air flow meter. the cell was provided with air for 15 minutes at a flow rate of 0.5 l/min then the power supply was switched on to provide the cell with the required current and started to record the time of experiment at the end of each run and before carrying out cod tests, solution ph was adjusted to 8.0 for removing residual fe+2 (fe+3) then filtrated and tested its cod value. conductivity and total dissolved solids (tds) were determined by utilizing “version com-100, hm digital inc., korea”. at the end of electrolysis, samples were collected and analyzed to check the cod and phenol concentrations. solution turbidity was measured by (jenway-6035, germany). so4 -2 and cl-1 was analyzed by using photo flex. series, (wtw model no 14541, germany). to determine the cod, a sample of effluent (2ml) was digested with k2cr2o7 for a period 120 min using cod thermos-reactor (rd125, lovibond) at a temperature of 150 °c, the sample was then cooled to room temperature before cod determining by a spectrophotometer (md200, lovibond). eq. 5 was used to compute the cod elimination efficiency, [26]: 𝑅𝐸% = 𝐶𝐼 − 𝐶𝐹 𝐶𝐼 × 100 (5) where cf represents the final cod (mg/l) while ci reflects the initial cod in milligrams per liter (mg/l). the specific energy consumption (sec) value represents the quantity of energy consumed during the process of digesting a kilogram of chemical oxygen demand. sec in (kwh/kg) can be calculated using eq. 6. [27]: 𝑆𝐸𝐶 = 𝐸×𝐼×𝑡 ×1000 (𝐶𝐼 −𝐶𝐹) ×𝑉 (6) where sec refers for specific energy consumption per kilogram of chemical oxygen demand (kwh/kg cod), e denotes the applied cell voltage (volt), t denotes the electrolysis period (h), i denotes the current (a), v denotes the effluent volume (l). 2.1. design of experiments response surface methodology (rsm) summarized as a collection of mathematical and statistical tools for determining a regression model equation that correlate an objective function with its independent variables [28]. the present study used a three-level, three-factor box–behnken design (bbd) to investigate the effects of process variables on cod elimination. "current density (x1)", "time (x2)", and "concentration of feso4(x3)" were considered as process factors, while the cod removal efficiency (re %) will be used as a responding. process factor scales were classified into three levels namely (-1), (0), (+1) for low, intermediate and high value, respectively [29]. table 2 depicts the process variables at their selected levels, while table 3 depicts the experiments array recommended by bbd for this work using minitab-17 software. table 2. variables in the process of hospital wastewater treatment along with their level. correlation between the response and its independent variables was determined in this study using the following second-order model and leastsquares approach [30]: 𝑌 = 𝑎0 + ∑ 𝑎𝑖 𝑥𝑖 + ∑ 𝑎𝑖𝑖 𝑥𝑖 2 + ∑ 𝑎𝑖𝑗 𝑥𝑖 𝑥𝑗 (7) where y is the response (removal %), i and j denote the index numbers for the pattern, a0 denotes the intercept term, and x1, x2,... xk denote the parameters used in the operation in coded form. the primary influence of the first order (linear) is denoted by ai. the second-order main effect is denoted by aii, and the interaction effect is denoted by aij. after doing an analysis of variance, for the purpose of demonstrating the model's suitability, the regression coefficient (r2) was computed. 3. results and discussion 3.1. results of experimental design according to bbd design, fifteen runs were performed to investigate the optimum conditions for cod removal. the experimental results for removal efficiencies (re percent) and specific energy consumption (sec) are summarized in table 4. results showed that efficiency of cod removal was in the range of 81.38 97.3% while the specific energy consumption ranged between (1.97014.294) (kwh/kg. cod). as a preliminary inspection, a comparison between run (6) and run (7) demonstrated that the concentration of feso4 has a significant effect on cod removal efficiency where re% increased from 81.38 to 92.465 % making a difference of 11.085 % as feso 4 concentration increased from 0.2to 0.8 mm at constant current density of 10ma/cm2 and time of 40 min. while the comparison between running (7) and (12) demonstrated that the density of current followed the concentration of feso4 in its impact on the cod removal efficiency where the re% increased from 92.465 to 97.3% which made a difference of 4.835% as the current density increased from 10 to 20 ma/cm2 at constant feso4 concentration of 0.8 mm and time of 40 minutes. variables of the process 𝐁𝐨𝐱– 𝐁𝐞𝐡𝐧𝐤𝐞𝐧 level levels that are coded low(-1) middle (0) high (+1) x1-current.density (ma/cm2 ) 10 15 20 x2time(min) 20 40 60 x3-fe so4(mm) 0.2 0.5 0.8 26 abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 table 4. box–behnken design (bbd)for cod elimination experimental results run order blocks parameters e (volt) re% sec 𝑲𝑾𝒉 𝒌𝒈 𝑪𝑶𝑫 x1 x2 x3 actual predicted 1 1 20 20 0.5 6.52 94.17 94.05738 5.065 2 1 15 60 0.8 5.565 95.125 95.51863 9.804 3 1 15 40 0.5 5.305 94.192 93.938 6.0333 4 1 10 60 0.5 4.525 90.065 90.17763 5.569 5 1 15 20 0.2 6.43 84.031 83.63738 4.242 6 1 10 40 0.2 4.53 81.38 81.4595 4.0996 7 1 10 40 0.8 4.885 92.465 91.95875 3.816 8 1 20 40 0.2 6.49 88.026 88.53225 10.974 9 1 20 60 0.5 6.22 96.093 95.77888 14.294 10 1 10 20 0.5 4.625 87.01 87.32413 1.970 11 1 15 60 0.2 5.265 85.02 84.82788 10.351 12 1 20 40 0.8 6.05 97.3 97.2205 9.053 13 1 15 40 0.5 5.32 93.856 93.938 6.252 14 1 15 40 0.5 5.305 93.766 93.938 6.269 15 1 15 20 0.8 5.335 91.942 92.13413 3.247 however, the precise effect of these parameters and their interactions can be observed via anova results. the findings of the removal effectiveness were evaluated using the minitab-17 program, and a quadratic model of the removal efficiencies (re percent) in terms of real units of process parameters was developed as follows: 𝑅𝐸% = 50.85 + 1.685 𝑋1 + 0.3406 𝑋2 + 55.47 𝑋3 − 0.0268 (𝑋1)2 − 0.003583 (𝑋2)2 − 38.61(𝑋3)2 − 0.00283 𝑋1𝑋2 − 0.302 𝑋1𝑋3 + 0.0914 𝑋2𝑋3 (8) in which x1x2, x1x2, and x2x3 denote the model parameters' interaction effects. x12, x22, and x32each constitute a parameter's principal influence. using equation 8, the predicted values of the cod removal efficiency was estimated and tabulated in table 4. in eq.8, the positive coefficient in front of any parameter reveals that re% increases with its increasing and vice versa. analysis of variance (anova) was used to determine the acceptability of bbd. it really is an analytical technique that utilizes fisher's f-test and p-test to estimate the model's and its parameters' significance [31]. in principle, bigger f-values and lower p-values indicate that the coefficient terms are more important [32]. table 5 illustrates an anova using the response surface model. in this table, contr.% denotes percentage of contribution of each variable, df represents degree of freedom of the model and their parameters, and the statistical terms are represented by sum of the square (seq. ss), adjusted sum of the square (adj. ss), and adjusted mean of the square (adj. ms) respectively. p-value of (0.0001) and f-value of (145.59) were obtained which elucidate that regression model is highly significance. the model's multiple correlation coefficient (r2) was 0.9962, indicating that the regression is statistically significant and only (0.0038) of the overall variation is not confirm by the model. the adjusted multiple correlation coefficient (adj. r2) =0.9894 and the predicted multiple correlation coefficient (pred. r2) =0.9435 in this model were well-matched since the difference between them less than 0.2 [33]. results of table 5 showed that feso4 concentration has the major effect followed by current density with contributions of 56.78% and 23.46% respectively. while time has a lower effect with contribution of 3.23%. the high contributions of current density and feso4 concentration confirm that ef governed by these two variables. this result is expected since ef process is governed by eq.2 where fe+2 is furnished externally and h2o2 is generated internally based feso4 and current density. the squared interactions are significant with a contribution of 15.43% in which squared interaction of feso4 concentration has the most effect. the 2-way interactions among the variables are non-significant. the p-value for lack of fit (0.120 > 0.05) indicates that the lack of model fit was not statistically significant in comparison to the pure error in this investigation [34]. as a result, the model can generate an adequate prediction that corresponds to the response values. table 3. experimentation with the box-behnken style run 𝐁𝐥𝐤 𝐂𝐨𝐝𝐞𝐝 𝐥𝐞𝐯𝐞𝐥𝐬 real value x1 x2 x3 current density (ma/cm2), x1 time (min), x2 feso4(mm), x3 1 1 1 -1 0 20 20 0.5 2 1 0 1 1 15 60 0.8 3 1 0 0 0 15 40 0.5 4 1 -1 1 0 10 60 0.5 5 1 0 -1 -1 15 20 0.2 6 1 -1 0 -1 10 40 0.2 7 1 -1 0 1 10 40 0.8 8 1 1 0 -1 20 40 0.2 9 1 1 1 0 20 60 0.5 10 1 -1 -1 0 10 20 0.5 11 1 0 1 -1 15 60 0.2 12 1 1 0 1 20 40 0.8 13 1 0 0 0 15 40 0.5 14 1 0 0 0 15 40 0.5 15 1 0 -1 1 15 20 0.8 abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 27 3.2. the influence of process factors on the efficiency of cod removal graphical representations of rsm can be used to demonstrate the influences of specified variables on the response. the figs. (2-i and 2-j) illustrate the effect of feso4 concentration on the re percent at different current densities (10-20 ma/cm2) during a constant time period (40 min.). fig. 2-i depicts the surface response plot, while fig 2-j depicts the contour plot. the surface plot revealed that, at the same current density (10 ma/cm2), an increase in cod removal efficiency occurs as the fe+2 intensity rises from 0.2 to 0.8 mm. the increasing in re% occurs rapidly at the first stage then tends to be sluggish at final stage. similar observation was identified at higher current density (20ma/cm2). this behavior can be interpreted as increasing fe+2 concentration improved the hydrogen peroxide's oxidizing ability to degrade big molecules, therefor increasing concentration of fe+2 leads to more degradation of organic compounds in wastewater [29]. previous studies showed that fe+2 has the ability to destroyed big molecule in wastewater such as dyestuffs, in real dyeing wastewater [35]. at any concentration of feso4, re% increases linearly with increasing of current density from 10 to 20 ma/cm2. this behavior of the effect of current density on re% is in agreement with previous work [36, 37] and could be explained as the current considers as the driving force for the reduction of oxygen on the cathode surface leading to generate h2o2 hence, by increasing the current density, more generation of •oh would be happened due to reaction of h2o2 with ferrous ions. the corresponding contour plot indicates that the ≥96 percent cod removal efficiency value is contained inside a limited area with a current density of (16-20 ma/cm2) and feso4 concentration of (0.5-0.8 mm). the shape of control plot indicates the nature and extent of the interaction. the figs. (3-i and 3-j) explain the impact of time on the re percent at varied current densities (10-20 ma/cm2) and constant feso4 concentration (0.5mm). (i) contour plot (j) values maintained for a period of 40 minutes figure 2. display of the impact of feso4 concentration and current density on the percent of re in a three-dimensional surface plot table 5. analysis of variance for chemical oxygen demanded reduction p-value f-value 𝐀𝐝𝐣. 𝐌𝐬 𝐀𝐝𝐣. 𝐬𝐬 𝐂𝐨𝐧𝐭𝐫. % 𝐒𝐞𝐪. 𝐬𝐬 𝐃𝐅 𝐒𝐨𝐮𝐫𝐜𝐞 0.001 145.59 35.887 322.981 99.62 322.981 9 model 0.001 365.95 90.205 270.615 83.47 270.615 3 linear 0.001 308.61 76.070 76.070 23.46 76.070 1 (x1) 0.001 42.46 10.465 10.465 3.23 10.465 1 (x2) 0.001 746.80 184.080 184.080 56.78 184.080 1 (x3) 0.001 67.64 16.674 50.022 15.43 50.022 3 square 0.049 6.73 1.658 1.658 0.12 0.381 1 "x1 ∗ x1" 0.003 30.78 7.586 7.586 1.56 5.050 1 "x2 ∗ x2" 0.001 180.90 44.590 44.590 13.75 44.590 1 "x3 ∗ x3" 0.123 3.17 0.781 2.344 0.72 2.344 3 2-way lnter. 0.306 1.30 0.320 0.320 0.10 0.320 1 x1 ∗ x2 0.138 3.33 0.820 0.820 0.25 0.820 1 x1 ∗ x3 0.078 4.88 1.203 1.203 0.37 1.203 1 x2 ∗ x3 0.246 1.232 0.38 1.232 5 error 0.120 7.48 0.377 1.132 0.35 1.132 3 lack of fit 0.050 0.101 0.03 0.101 2 "pure-error " 100.00 324.213 14 total r2(pred.) press r2(adj.) r2 s. model-summary 94.35% 18.3331 98.94% 99.62% 0.496481 28 abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 as illustrated in fig. 3-i, the effectiveness of cod elimination is exponentially grown in proportion to the growth of time then started to be approximately constant beyond 40 min for any values of current density. these findings agree those seen in the previous studies [38-41]. the findings indicate that the reaction time has a positive impact on the progress of the ef process for a limited period. the corresponding contour plot (3j) indicates that the ≥96 percent cod elimination efficiency occurs in a limited area with a current density of (19-20 ma/cm2) and a time range of 35-55 minutes. (i) (j) figure 3. shows the effect of time and current density on the re percent using a 3d surface plot (i) and a contour plot (j). (maintain value: feso4 concentration =0.5mm). the figs. (4-i and 4-j) illustrate the impact of time on the re percent for varied feso4 concentrations (0.2-0.8 mm) and a constant current density of 15ma/cm2. at any feso4 concentration, fig. (4-i) demonstrates that the cod removal efficiency increases exponentially with increasing time. the reaction time has a positive effect on the progress of electrofenton process up to 40min then start to sluggish. at any time, the results show that the increasing in re% occurs rapidly at the first stage then tends to be sluggish at the final stage when concentration of feso4 increased from 0.2 to 0.8mm. the corresponding contour fig. (4-j) demonstrates that the ≥95 percent cod removal efficiency value is contained within a limited area with feso4 concentrations ranging from (0.6-0.8 mm) and times ranging from (35-60 min). as a result, the application of rsm enabled the identification of feasible optimum values for the researched parameters, as well as its function in providing valuable information about the interactions among variables. (i) (j) figure 4. shows the impact of time and concentration of 𝑭𝒆+𝟐 on the re percent using a 3d surface plot (i) and a contour plot (j). (hold value: current density =15 𝒎𝑨 𝒄𝒎𝟐 ) abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 29 improving of an electrochemical system is essential to reduce energy losses. numerous criteria should be considered when optimizing the system in order to achieve the desired target via maximization of the desirability function (df) [28]. the target function choices could be "maximized", "objective", "minimize", inside the limit, and neither one. the target of cod removal was designated as the ‘maximum’ with df=1.0. the process factors studied in the present work were recognized within current at range of (10-20 ma/cm2), feso4 concentration at range of (0.2-0.8mm), and time at range of (20-60 min). a cod elimination effectiveness of 81.38 percent was chosen as the lower limit value, while the upper limit value was allocated at 97.3%. under these boundaries and settings, optimization was carried out and the results are shown in table 6. two confirmative runs were conducted under the optimized settings to verify them; the results are shown in table 7. after electrolysis of approximately 49 min, cod removal efficiency of 97.83% as average value was achieved at ph=3 that is consistent with optimization analysis limiting range of the optimal value (table 6). as a result, bbd is effective and useful at optimizing removal efficiencies via the porous graphite–graphite ef system. table 8 shows a comparison between untreated and treated sewage based on the results of this study. as can be seen, treated wastewater has improved characteristics and conforms to the standard limits for effluent discharge (100ppm) [26]. chemical oxygen demanded removal efficiency of 97.96%, phenol removal efficiency of 96.58%, and turbidity removal efficiency of 96.70% based on the raw effluent properties were achieved in the present work approving the activity of ef process in treatment wastewater generated from aldiwaniyah hospital in removal both of cod and turbidity. the increase in sulfate ions in the treated effluent is due to the using of ferrous sulphate while the decreasing in clions is due to the generation of some chlorine on the anode which has another benefit for decreasing cod due to indirect oxidation of pollutant by clo[27]. the present work demonstrates that the graphite–graphite ef system may be effectively utilized to the treatment of aldiwaniyah hospital wastewater. starting from an initial cod of 786 ppm, it could be achieved a cod removal efficiency of 97.964% at operating time of approximately 49min with an energy consumption not exceeded 10.78 kwh/kg cod. in comparison with our previous work [27]. using the same source of wastewater and applying an electrocoagulation method, the present system is more efficient in term of time and energy consumption where in our previous work by beginning with an initial chemical oxygen demand (745 ppm), the effectiveness of cod elimination of 99.3% was achieved at electrolysis time of 90 min with energy consumption of 26.079 kwh/kg cod , while in present work, approximately the same removal efficiency of cod was obtained at 49min and 10.78 kwh/kg cod. this an indication that ef process oxidizes the refractory natural or organic compounds that existing in hospital wastewater in a more proficient way. moreover, the present system could be considered as an economic one since it used electrodes made from cheap materials and its specific energy consumption is approximately lower and suitable in comparison with previous studies [27]. 4. conclusions the present work examined the reduction of chemical oxygen demand from hospital sewage by electrofenton process using an electrochemical cell table 6. process parameter optimization for optimal cod removal efficiency (re %). 𝐑𝐞𝐬𝐩𝐨𝐧𝐬𝐞 𝐆𝐨𝐚𝐥 𝐋𝐨𝐰𝐞𝐫 𝐓𝐚𝐫𝐠𝐞𝐭 𝐔𝐩𝐩𝐞𝐫 𝐖𝐞𝐢𝐠𝐡𝐭 𝐈𝐦𝐩𝐨𝐫𝐭𝐚𝐧𝐜𝐞 re (%) 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 81.38 maximum 97.3 1 1 solution: parameters results current density (ma/cm2) feso4 (mm) time (min) r e (%) fit df se fit 95% ci 95% pi 20 0.697 48.687 97.97 1 0.362 (97.035, 98.896) (96.386, 99.545) table 7. confirmative value of the optimum cod removal efficiency run current density (ma/cm2) feso4 (mm) time (min) e (volt) cod (ppm) r e (%) ec (kwh /kg cod) initial final actual average 1 20 0.697 48.687 6.03 786 16 97.964 97.831 10.78 2 20 0.697 48.687 6.045 782 18 97.698 10.89 table 8. comparison between untreated and treated sewage parameter effluent cod (ppm) phenol (ppm) turbidity (ntu) so4-2 (ppm) cl (g/l) raw effluent 786 0.38 11.2 400 1.6 treated effluent 16(97.964%) 0.013(96.58%) 0.37(96.70%) 810 0.95 30 abdulla y. ghjair ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 023–031 having cathode and anode made from porous graphite. impacts of current density, feso4 concentration on the chemical oxygen demand reduction from the hospital wastewater generated at aldiwaniyah hospital located in iraq were investigated using rsm. based on rsm, the optimal conditions were current density of 20ma/cm2, feso4 concentration of 0.697 mm and time of 48.7 min, in which cod removal and specific energy consumption were 97.964% and 10.78 kwh/kg. cod respectively. the high value of r2, adj.r2 and pred. r2 value indicate that the model fitted very well to the experiment data and rsm was successfully applied to analyze the impact of various operating factors at lower number of runs and lower cost of chemicals. the efficiency of graphite–graphite ef system was found to be influenced by two main parameters current density and feso4 concentration in which feso4 concentration has the main effect followed by current density. the present system gave better performance and lower energy consumption in comparison with previous works due to the powerful oxidation mechanism adopted in the present system. graphite– graphite ef technique for the removal of cod from sewage water was shown to be an environmentally beneficial procedure, according to the findings of current study. acknowledgment the authors like to extend their appreciation to the staff members of the chemical engineering department at the university of al-qadisiyah, college of engineering for their technical assistance in completing this research. references [1] christova-bagdassarian, v. and m. atanassova, spectrophotometric determination of sodium azide in workplace air. journal of the university of chemical technology and metallurgy, 2007. 42(3): p. 311-314. 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[41] yan, l., et al., comparative study of different electrochemical methods for petroleum refinery wastewater treatment. desalination, 2014. 341: p. 87-93. article al-qadisiyah journal for engineering sciences 14 (2021) 134–143 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: ali.abbar@kecbu.uobaghdad.edu.iq (ali h. abbar) https://doi.org/10.30772/qjes.v14i2.768 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. treatment of al-dewaniya hospital wastewater by electrocoagulation method using ss/fe electrodes. riham gh.najeeb a, ali h. abbar b* achemical engineering department, university of al-qadisiyah, iraq bdepartment of biochemical engineering, al-khwarizmi college of engineering, university of baghdad, baghdad, iraq a r t i c l e i n f o article history: received 2 august 2021 received in revised form 25 august 2021 accepted 12 september 2021 keywords: hospital wastewater, electrocoagulation, cod, optimization, rsm. a b s t r a c t the present study focused on the treatment of hospital wastewater generated from al-diwaniya hospital located at al-diwaniya city/ southern iraq via an electrocoagulation (ec) process with ss/fe electrodes. response surface methodology (rsm) was used to evaluate the main effects of parameters, their simultaneous interactions and quadratic effect to achieve the optimum condition for ec process. chemical oxygen demand (cod) was observed and measured for each experiment as it can be used as a good indicator of the quality of wastewater. the impacts of three factors such as current density (5-25ma/cm2), ph (4-10), and addition of nacl(0-3g/l) were evaluated. the obtained experimental data were fitted to a second-order polynomial equation with analyzing by variance analysis (anova). the results shown that current density has the major impact on the efficiency of cod removal followed by addition of nacl while ph has the lower effect on the cod removal under the studied range of ph. anova results showed that the determination coefficient of the models was r2 98.18% confirming that the quadratic model was significance with a good fitting between the experimental and predicted results. the optimized operating parameters were a current density of 25 ma/cm2, ph of 7.8,and nacl addition of 3 g/l in which cod removal efficiency of 97.14% was achieved with a specific energy consumption of (30.914) kwh/kgcod. © 2021 university of al-qadisiyah. all rights reserved. 1. introduction hospitals release significant quantities of contaminants into their wastewaters. medical waste management is a significant issue for countries all around the world, particularly because of the dangers it presents to the environment. ö. gökkuş et al. [1]. hospitals are general offices that offer health services to people from all walks of life and serve as medical offices for health and research education. hospitals may host a wide range of activities, from nonmedical to medical, all of which create solid, liquid, and gas wastes. these wastes will have an influence on the land, water, and air. purwanto et al.[2]. hospital waste waters (hwws) consider as the most harmful kinds of pollutants at the nature. hwws contain pathogens such as bacteria, parasites, viruses, as well as radioactive isotopes and hazardous chemical compounds. dehghani et al. [3]. untreated medical waste can have disastrous consequences not only for those working in clinical facilities, but also for those in the surrounding community. el-haggar et al.[4]. as a result, this kind of pollutants cannot be discharged into the sewerage system as untreated effluent. ö. gökkuş et al.[1] . in case of treated hospital wastewaters, they can be reused for agricultural purposes. beier et al. [5]. the treatment of hwws is mostly quite complex since each effluent has its http://qu.edu.iq/ https://doi.org/10.30772/qjes.v13i http://creativecommons.org/licenses/by/4.0/ 135 riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 134–143 nomenclature adj. ms adjusted mean of the square hwws hospital waste waters 2adj. r adjusted coefficient of multiple correlation i current applied (a) adj. ss adjusted sum of the square ntu turbidity ia the first-class(linear) major effect pred. r 2 predicted multiple correlation coefficient jia second-class major effect re% removal efficiency (%) ijja the interaction effect r 2 linear regression coefficient anova analysis of variance rsm response surface methodology al aluminium sec specific energy consumption (kwh/kg cod) bbc box–behnken design seqss sum of the square ce current efficiency (%) ss stainless steel ci confidence interval t time cr. % percentage contribution for each parameter toc total organic compound cod chemical oxidation demand tds total dissolved solid contr. percentage contribution for each parameter, % v 3volume of electrolyte, cm dc direct current power supply 1x coded value of current density df the desirability function x1 current density dof degree of freedom 2x coded value of ph u voltage of cell, volt x2 ph ec electrocoagulation 3x coded value of nacl addition f faraday constant (96500) , a s mol-1 x3 nacl addition fe iron y represents the dependent variable (re, %) own characteristics that may be different from others hence poses specific troubles for treatment. tekin et al.[6] the conventional methods for treating hwws are basically biological and physiochemical processes [7],[8]notwithstanding, these strategies have shown restricted accomplishment for the treatment of hwws because of the nature and structure of these effluents . a lot of sludge were produced when using chemicals in sewage processing system, meanwhile the microbiological processing system involves using large area of land and long processing time, therefore the conventional processing methods have been less application in this field. murdani et al.[9]. another alternative approach that can be tried to cover the shortage of conventional technology is called electrocoagulation process. kermet et al.[8] electrocoagulation (ec) is an electrochemical technique that uses soluble electrodes such as aluminum or iron. when voltage is applied to the soluble electrodes, active cation species or "mediators" are generated, which can react with the target pollutant. hydrogen generated at the cathode also aids in the separation of formed flocs. mission et al.[10] the employment of electrons rather than chemical reagents or microbes to assist electrochemical treatment in the elimination of hazardous organic contaminants is extremely intriguing. carlesi jara et al. [11]. electrochemical process has many advantageousness over traditional ones because of its unique properties, such as less chemical addition, simple design, reduced sludge generation, little area required for setup, and very quick sedimentation due to the development of flocs. bracher et al.[12]. ec systems have high efficiency, a rapid reaction rate, cost-effectiveness, and compact size (enabling decentralized treatment), easy automation. palahouane b et al.[13] and no hazardous material creation. they created minimal tds and secondary pollutants, and have the ability to remove the smallest size of colloidal particles as well. m. yoosefian et al.[14] . ec is an electrochemical management approach that produces active coagulants using sacrificial anodes. many mechanisms are used in this procedure to remove contaminants from aqueous effluents. as an anodic reaction, the dissolution of fe and production of adsorbents (hydrated iron hydroxides) occurred simultaneously with the evolution of hydrogen gas as a cathodic reaction, resulting in absorbent flotation. as a result, either gas flotation or sedimentation can be used to remove the produced flocs. all reactions that happened at the surface of the anode and cathode, as well as in the solution, during electrocoagulation are represented by equations (1, 2, and 3) [8],[15] : anodic reaction: fe →fe3+ + 3e (1) cathodic reaction: 3h2o + 3e →3/2h2(g) + 3oh (2) in the solution: fe3+ (aq) + 3h2o→ fe(oh)3 + 3h + (aq) (3) at the electrocoagulation process, two interaction mechanisms between hydrolysis products and contaminant were observed namely adsorption and precipitation each of which is suggested for a different ph range. flocculation at low ph levels is explained by precipitation, whereas at higher ph levels, it is explained by adsorption. gökkuş et al.[1]. electrocoagulation (ec) can remove toxic pollutants from wastewater, such as cr(iv), dyes, olive mill pollutants, vepsa¨la¨inen m et al.[16].cod from petroleum refinery effluent, alkurdi et al.[17] and is a good choice for wash water treatment wang et al. [18], industrially processed water, and medicinal water treatment. bajpai et al.[15]. for a better experimental methodology, statistical methods were favored for the finding the optimal combinations of parameters and their interactions. these methods offer benefits such as reducing time and study costs .montgomery d.c et al.[19]. response surface methodology (rsm) is a statistical approach for designing and optimizing trials in which the experimental responses are fitted to quadratic functions. kalil s.j et al.[20]. the dependent variable value is estimated using the rsm regression modeling approach, which is depended on the controlled values of independent variables. this approach generates a large number of trial combinations in a short amount of time to improve laboratory testing results. in order to fit a quadratic model, bbd plans only work at three levels for one of each factor with the fewest runs. the estimated parameter may be used to compute the factor that contributes the most to the estimated value, so allowing researchers to emphasis on the 136 riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 134–143 parameters most important to accept the product. m. otto et al.[21] .rsm has been used to model and optimize wastewater treatment systems with a great success [22],[23]. the aim of this study was to evaluate the feasibility of using an electrocoagulation process using iron electrode as cheap material to treat wastewater generated by a local iraqi hospital called the general hospital, which is located at al-diwaniya city. the impacts of operating parameters such as current density, ph, and nacl addition on the efficiency of cod removal from hospital wastewater were studied, and the optimum conditions were determined by using rsm. 2. experimental work hospital wastewater was collected from the al-dewaniya hospital's sewage system (located at al-diwaniya city, iraq) right before it was mixed with the campus's household wastewater. table 1 shows the characteristics of hospital wastewater. during the experimental program, this hospital wastewater was stored at 4 0c, and the needed sample for each experiment (0.7 l) was taken at the time of each experiment . table 1 -physiochemical properties of effluents in al-dewaniya hospital sewage system. parameter value cod(mg/l) 735 ph 7.8 t.d.s(mg/l) 2480 cl-(mg/l) 1.4 so4-2(mg/l) 0.7 turbidity(ntu) 9.5 conductivity (ms/cm) 1.95 all experiments were carried out in a batch system using a cylindrical jacketed perspex electrochemical cell having a length of 200 mm, diameter of 100 mm with an internal thickness of 5 mm,(fig.1). the cell has a working capacity of around 0.7 l. the cover of the cell has exterior dimensions of (130 mm outer diameter and a thickness of 10 mm) and has five slots for electrode inserting and holes for embedding ph and conductivity meter, as well as sample taking out. as cathode and anode electrodes, three stainless steel and two iron plates with dimensions of 15 × 5 × 1 cm were used respectively. a 2.5 cm gap between the anode and cathode was fixed. to ensure homogeneity inside the reactor and reduce floc separation, stirring the mixture at 300 rpm was applied. bajpai et al.[15]. by using a water circulator (memmert, germany,type: wnb22), all runs were achieved at a constant temperature of 25±2 oc. the tested hospital waste water was found to have a low conductivity 1.95ms/cm, causing an increase in cell potential. in this case, supported electrolyte should be used to rise the conductivity of solution. sodium sulfate (na2so4) was used as electrolyte at a concentration of 0.05 m, resulting in a final conductivity of 12.9 mscm-1, which is within the needed range for obtaining low cell potential. souza et al.[24]. the ph of the solution was measured by digital ph meter (hnna instrument inc.ph211, romania) and adjusted using 0.1 m naoh or 0.1 m h2so4. conductivity and tds were determined using (hm digital inc. model com-100, korea). to deliver the required electrical current, a dc power supply (uni-t, utp3315pf) with a maximum voltage of 30 v and a maximum current of 5 a was utilized. anodes and cathodes were washed with ethanol and water before each cycle to eliminate contaminants. after filtering the samples of each run, the cod value was calculated to assess the process' performance. all of the trials were repeated three times and only the average values were taken. figure 1 -the electrochemical system: 1) cell body, 2) jacket, 3) iron anode, 4) stainless steel cathode , 5) magnetic stirrer, 6) power supply, 7) voltmeter 8) ammeter,9) ph-meter,10) water bath circulator. by using cod thermos-reactor (rd125, lovibond), a sample (2ml) of effluent was digested with k2cr2o7 at 150 °c for 120 minutes to determine its cod value after cooling it to room temperature, then analyzing it in a spectrophotometer (md200, lovibond). the removal efficiency of cod was calculated using eq. 4, şengil et al.[25]: 𝑅𝐸% = 𝐶𝑖−𝐶𝑓 𝐶𝑖 × 100 (4) where ci is the initial concentration (mg/l) and cf is the final concentration (mg/l) iron consumption was determined by weighing electrodes before and after each experiment, and the fe consumption (kgm-3) was estimated using eq. 5: fe consumption (kgm-3) = (initial weight – final weight) / volume of sample (5) the quantity of energy required to digest one kilogram of cod is known as the specific energy consumption (sec). eq. 6 may be used to calculate sec in (kwh/kg) . alkurdi et al.[17]: 𝑆𝐸𝐶 = 𝑈.𝐼.𝑡 ×1000 (𝐶𝑂𝐷𝑖−𝐶𝑂𝐷𝑓) 𝑉 (6) where sec is the specific energy consumption (kwh/kg cod), i is the current (a),u is the applied cell voltage (volt), t is the electrolysis time (h), v is the volume of effluent(l), and codi and codf are the initial and final values of cod (mg/l). 2.1. experimental design model fitting and determining the optimum operating conditions for a response can be achieved by using a collection of statistical and mathematical techniques formulated by minitab-17 software. in minitab17 software, there are a variety of techniques for optimization of the response, but in this study, the box bhenken design was used to optimize and determine the influence of factors like current density, ph, and electrolyte (adding nacl) on cod elimination effectiveness by electrocoagulation. current density (5-25ma/cm2), ph (4–10), and nacl addition (0-2g/l) were the range of operational factors. the chosen values of operational factor were designed based on reviewing some literatures [6], [15],[26],[27]. the factors were labeled as x1, x2, and x3 in table 2. all factors were divided into three categories, with -1, 0, and +1 representing low, moderate, and high values, respectively. before starting riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 000–000 137 the experimental runs, a preliminary run was achieved to determine the suitable electrolysis time. the selected operating conditions were current density (25ma/cm2), ph (7), and nacl addition (1.5 g/l). results of cod deceasing with time is shown in table 3. based on the results of table 3, it was found that electrolysis time of 90 min being the suitable for achieving the experimental design to give significant results of rsm since the removal efficiency of cod is greater than 80%. using higher time may be not giving a clear picture for the effects of parameters. table 2process parameters and their levels. process parameters range in box–behnken design coded levels low(-1) middle(0) high (+1) x1current density (ma/cm2) 5 15 25 x2ph 4 7 10 x3-nacl (g/l) 0 1 2 table 3selecting the best electrolysis time based on decreasing of cod with time. time (min) 0 20 40 60 70 80 90 100 120 cod(mg/l) 759 714 620 541 400 236 130 60 20 based on minitab-17 software using box bhenken design, 15 runs should be performed in a trial design with three repetitions of the center point . repetition is useful for evaluating pure errors from sum of squares. table 4 illustrates the bbd proposed for the present research. table 4boxbehnken experimental design. run blocks coded value real value x1 x2 x3 current density ph x2 nacl (g/l) x3 1 1 0 0 0 15 7 1.5 2 1 1 -1 0 25 4 1.5 3 1 0 1 1 15 10 3 4 1 0 0 0 15 7 1.5 5 1 -1 -1 0 5 4 1.5 6 1 0 -1 1 15 4 3 7 1 -1 0 -1 5 7 0 8 1 1 0 -1 25 7 0 9 1 0 0 0 15 7 1.5 10 1 0 1 -1 15 10 0 11 1 1 0 1 25 7 3 12 1 0 -1 -1 15 4 0 13 1 1 1 0 25 10 1.5 14 1 -1 0 1 5 7 3 15 1 -1 1 0 5 10 1.5 for the assessment of results, bbd provides correlation in which the data are set in a 2nd order polynomial equation as follows [17] : 𝑌 = 𝛽0 + ∑ 𝛽𝑖 𝑥𝑖 + ∑ 𝛽𝑖𝑖 𝑥𝑖 2 + ∑ 𝛽𝑖𝑗 𝑥𝑖 𝑥𝑗 (7) where y represents the response (re%), i and j are patterns index numbers, β_0 is intercept term, x_1, x_2 … x_k are coded form of process variables. β_i is the first-order(linear) main effect, β_ii second-order main effect and β_ij is the interaction effect. anova was applied then the regression coefficient (r2) was calculated to check the model fit goodness. 3. results and discussion 3.1. statistical analysis to investigate the combined impact of the independent variables on cod removal efficiency, fifteen batch runs were conducted at various process variable combinations. table 5 shows the experimental findings obtained after 90 minutes of electrolysis time, including cod removal efficiency (re%), fe consumption, and specific energy consumption (sec). table 5experimental results of box–behnken design for cod removal. run order pt type blocks x1 x2 x3 re% iron cons ec actual predicted 1 0 1 15 7 1.5 93.40 93.2133 2.23 12.276 2 2 1 25 4 1.5 92.50 92.4500 3.8 27.966 3 2 1 15 10 3 95.57 95.9000 2.25 11.113 4 0 1 15 7 1.5 93.85 93.2133 2.51 12.296 5 2 1 5 4 1.5 84.90 85.5150 1.21 2.455 6 2 1 15 4 3 93.30 93.0650 2.3 10.892 7 2 1 5 7 0 88.90 88.6150 0.7 2.665 8 2 1 25 7 0 95.18 95.5600 4.1 30.233 9 0 1 15 7 1.5 92.39 93.2133 2.21 11.990 10 2 1 15 10 0 91.97 92.2050 2.21 14.266 11 2 1 25 7 3 97.96 98.2450 3.72 26.260 12 2 1 15 4 0 90.00 89.6700 3.17 14.156 13 2 1 25 10 1.5 94.90 94.2850 3.52 30.124 14 2 1 5 7 3 93.40 93.0200 2.72 1.988 15 2 1 5 10 1.5 89.00 89.0500 1.23 2.534 cod removal efficiency ranges from 84.90 to 97.96%, as can be observed. the iron consumption ranges from (0.7-4.1) kg/m3. (1.98830.233)kwh/kg cod is the energy consumption range. the variation between the design's centre points is less than 2%, indicating high outcomes repeatability. based on minitab-17 software, an quadratic model in term of real units of process variables was obtained which relates cod removal efficiency (re%) with process variables as shown in eq.8: re% = 61.20 + 1.351 x1 + 2.722 x2 + 9.87 x3 0.02042 (x1) 0.1200 (x2)2 1.297 (x3)2 0.0072 x1x2 0.1005 x1x30.233 x2x3 (8) where re% is the response, and x1, x2, and x3 are current density, ph, and addition of nacl respectively. whereas x1x2, x1x3, and x2x3 represent the interaction effect of parameters. (x1)2, (x2)2 and (x3)2 represent a measure of the main effect of parameters current density, ph, and nacl addition respectively. the effects of individual parameters (linear and quadratic) or double interactions on cod removal efficiency are shown in eq.(8), where cod removal efficiency increases with increasing factors whose coefficients have positive values, whereas cod removal efficiency decreases with increasing factors whose coefficients have negative values. current density, ph, and the addition of nacl all have a favourable impact on cod removal efficiency, but all interactions have a negative impact. the predicted cod removal efficiency values were calculated using equation 8 and reported in table 5. the anova of the response surface model is shown in table 6. in this table, df, seqss, adj ss, adj ms,and contr .%, represent degree of freedom, sum of the square, adjusted sum of the square, adjusted mean of the square, and the contribution for each parameter respectively. fisher ftest and p-test are denoted by f-value, and p-value respectively. the model's acceptance was tested using f-value, and p-value. when the f138 riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 134–143 value of the regression equation is big, it can fit most of the variation in the answer. the p-value is used to determine if f has a large enough value to acknowledge the model's statistical significance. at a p-value less than 5%, 95 % of the model's variability could be explained. segurola et al.[28] table 6analysis of variance for cod removal of hospital wastewater treatment. source. dof seq. ss contr.(%) adj. ss adj. ms fvalue pvalue model. 9 143.110 98.18 143.110 15.9011 29.90 0.001 linear 3 113.607 77.94 113.607 37.8690 71.21 0.000 (x1) 1 74.054 50.80 74.054 74.0544 139.25 0.000 (x2) 1 14.418 9.89 14.418 14.4184 27.11 0.003 (x3) 1 25.134 17.24 25.134 25.1340 47.26 0.001 square 3 28.019 19.22 28.019 9.3395 17.56 0.004 x1*x1 1 2.592 1.78 2.789 2.7894 5.25 0.071 x2*x2 1 16.943 11.62 15.054 15.0537 28.31 0.003 x3*x3 1 8.484 5.82 8.484 8.4840 15.95 0.010 2-way inter 3 1.485 1.02 1.485 0.4949 0.93 0.491 x1*x2 1 0.722 0.50 0.722 0.7225 1.36 0.296 x1*x3 1 0.740 0.51 0.740 0.7396 1.39 0.291 x2*x3 1 0.022 0.02 0.022 0.0225 0.04 0.845 error 5 2.659 1.82 2.659 0.5318 lack of fit 3 1.541 1.06 1.541 0.5137 0.92 0.559 pureerror 2 1.118 0.77 1.118 0.5590 total 14 145.769 100 model-summary s. r2. r2(adj.) press r-sg(pred) 0.729248 98.18 % 94.89% 27.1709 81.36% table 6 shows that the quadratic model is significant, with a 95 percent confidence level and an f-value of 29.90. the cod elimination model's p-value was estimated to be 0.001, indicating that the created model is significant. furthermore, in comparison with to pure error, the lack of fit is not significant (p-value=0.559> 0.05), demonstrating that the model is effective, appropriate, and significant in describing the ec process's pollution removal [29],[30].the three most essential correlation coefficients in the statistical summary model are correlation coefficient (r2), adjusted correlation coefficient (adj. r2), and predicted correlation coefficient (pred. r2). to provide a high degree of fitting between observation and estimate value, the correlation coefficient (r2) should be near to 1. zhao et al.[31]. based on the value of adj. r2, which does not always rise with the addition of variables, the sample size and number of terms in the models might be adjusted. as a result, the adj. r2 value should be extremely near to the r2 value. furthermore, the difference between adj. r2 and pred. r2 should be less than 0.2 for the experimental and model predicted values to be in excellent agreement. zhao et al.[31]. in the present work, values of r2, adj. r2, and pred. r2 were found to be 0.9818, 0.9489 and 0.8136 respectively. this demonstrates that the experimental and model predicted values are compatible. furthermore, the difference between adj. r2 and pred. r2 was 0.1353, indicating the model's high significance. table 6 shows that current density (x1) was the most important factor influence on cod removal, accounting for a proportion of the total contribution (50.80%). the effect of adding nacl (x3) is the second most important, accounting for 17.24% of the total, indicating the significance of chloride ions in the breakdown of organic compounds during electrocoagulation. the ph factor (x2) has a lower influence on cod removal with a percentage contribution (9.89%) when the ph range (4-10) was used, demonstrating that the highest pollutant removal efficiency may be achieved in this ph range bajpai et al.[15]. different works [32],[33] found similar outcomes. furthermore, interaction effects are not significant. the quadratic effects on cod elimination were found to contribute 19.22%, with the quadratic impact of current density (x1) being non-significant in comparison to ph and nacl addition. 3.2. effect of process variables on the cod removal efficiency the influence of process parameters and their combinations on cod removal efficiency was studied using graphical demonstrations of statistical optimization based on rsm. fig (2-a, 2-b) show the combined effects of current density and solution ph on cod removal efficiency when nacl (1.5g/l) is added at a constant rate. the response surface plot is shown in fig 2-a, while the contour plot is shown in fig 2-b. fig 2-a shows that increasing current density increases cod removal effectiveness over the ph range (4-10). for example, increasing the current density from 5 to 25ma/cm2 results in a significant increase in cod removal from 84.90% to 92.50% at ph=4 (table 6, exp.2 and 5). besides, approximately the same increasing in cod removal efficiency was occurred at ph=10 from 89.00% to 94.90% (exp.13 and 15, table 6). when the ec procedure was carried out with an iron electrode, it was discovered that current density had the greatest impact on cod elimination efficiency. the rationale for these findings may be explained using faraday's rule, which states that rising current density causes dissolving rate of fe anode to rise, resulting in an increase in the formation of coagulants (fe(oh)3 particles) at the anode. liu et al.[34]. furthermore, the size and rate of formation of hydrogen gas bubbles play an important role in the removal of pollutants by floatation, with an increase in current density leading to an increase in production rate and a decrease in bubble size elazzouzi et al.[35]. furthermore, when the number of bubbles produced at the cathode rises, the mass transfer rate and floc production increase. yoosefian et al.[36]. previous research [36],[37],[38] had shown similar findings. (a) riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 000–000 139 (b) figure 2 the combined effects of current density and solution ph on the cod removal efficiency at constant addition of nacl (1.5 g/l): (a) 3d surface plot,(b) contour plot . as shown in fig. 2, raising the ph enhances cod removal effectiveness; for example, increasing the ph from 4 to 10 at a current density of 5ma/cm2 leads in an increase in cod removal from 84.90% to 89.00% (table 6, exp.5 and 15). at larger current densities, however, this increase in cod removal efficiency became less noticeable. clearly, the influence of ph on cod removal efficiency is greater at ph values of 4–7 than at ph values of 7–10.besides at ph 7-10, fig.2.b showed that ph starts to decrease when increasing ph beyond 8. however this deceasing is relatively low in comparison with increasing in ph observed at ph range 4-7. this behavior may be interpreted as follows: the decline in efficiency at acidic ph might be due to a lack of hydroxyl ions as well as very low fe(oh)3 production. furthermore, iron hydroxide particles are soluble at low ph (less than 7) and so do not have the potential to absorb contaminants. at ph 7,the insoluble fe(oh)3, fe(oh) 2+, fe2(oh)2 4+ and fe13(oh)32 7+ are the dominant compounds and have the ability to adsorb the pollutants . at high ph values, fe(oh)4 is formed which is soluble in water, decreasing the removal effectiveness, especially at ph greater than 10[35,40]. fig. 3. predominance-zone diagrams for fe+3, it was observed that fe(oh)3 is predominant species in the ph range(6-9) conferring the effect of ph on cod removal. barrera-diaz et al.[39]. different literatures [40],[41],[42] have shown similar results. based on the contour plot findings, it is evident that a cod removal efficiency of ≥94% could be accomplished within a certain ph range (610) and current density range of 18-25 ma/cm2. figure 3 predominance-zone diagrams for fe+3 chemical species in aqueous solution [41]. at constant solution ph=7, the combined effects of current density and addition of nacl on cod removal efficiency are shown in fig (4-a, 4b).fig 4-a denotes the response surface plot while fig 4-b demonstrates the equivalent contour plot. it can be shown in fig 4-a, that increasing current density increases cod removal efficiency across the whole range of nacl addition. the elimination effectiveness of cod improves with increasing nacl addition, as seen in fig.4, as nacl was added up to 3g/l at a current density of 5ma/cm2, cod removal efficiency rose from 88.90% to 93.40% (table 6, exp.7 and 14) when compared with no addition. according to literature reviews, adding nacl to the ec process can improve efficiency by lowering the cell voltage resulting in lowering the process energy consumption. furthermore, with the presence of nacl electrolyte, the opposing effects of anions such as co32-, hco3 − and so4 2−, can be avoided. the presence of such anions causes ca2+ or mg2+ cations to precipitate as an insulating layer on the cathode surface, hence increasing the ec cell's ohmic resistance. ahmadzadeh et al.[43]. adding nacl to the electrochemical process also causes the following reactions: 2cl→cl2 + 2e (9) cl2 + h2o→ hocl + cl+ h+ (10) hocl → ocl+ h+ (11) according to reactions 9 and 10, clmay oxidize to cl2, a powerful oxidant that may aid in the oxidation of dissolved organic compounds, or it may lead to the production of hocl, a strong oxidizer that may result in additional cod elimination in addition to electrocoagulation. singh et al.[43] . similar findings were reported in other studies[26],[43],[44]. based on the contour plot findings, it is evident that a cod removal efficiency of ≥96% could be achieved within a range of nacl addition (23g/l) and current density (12-25 ma/cm2). (a) 140 riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 134–143 \ (b) figure 4 the combined effects of current density and addition of nacl on the cod removal efficiency at constant solution ph=7(a) 3d surface plot,(b) contour plot . 3.3. the optimization and confirmation test for optimizing the system using minitab-17 software, many criteria should be considered to get desired objective by making the desirability function (df) maximum as possible as via adjusting the weight or importance. five options should be considered as a target namely maximize, objective, minimize, within the range, and none. the aim of optimization is to get higher removal efficiency of cod therefore cod removal was selected to be the maximum with corresponding weight of 1.0. the parameters studied in this research were identified within the range of the designed levels (table 2). the lower and upper values of cod removal efficiency were allocated at 84.9% and 97.96% respectively. optimization has been achieved using response optimizer of minitab-17 software based on these constrains and settings. results of optimization are illustrated in table 7 with the desirability function of (1). for confirming the optimization results, two experiments were performed based on the optimized parameters as shown in table 8. after 90 min of the electrolysis, 97.335% cod removal efficiency (average value) was accomplished which is in compactible with the range of the optimum value obtaining from optimization results (table 7). therefore, box– behnken design combined with desirability function can be applied as successful and effective method for optimizing cod removal using ec process. further experiments were conducted in which ph value of 7 was considered maintaining other parameters at their optimal values and its results tabulated in table 8. results showed that the possibility of using ph=7 with approximately good cod removal efficiency (94.93%) with the same energy consumption. a comparison between the characteristics of treated effluent based on the present work with the characteristics of effluent without treatment is shown in table 9. it was clear that treated effluent has enhanced characteristics with a cod removal efficiency of 97.14%. table 7optimization of process factors for maximizing cod removal efficiency (re%). respon se aim lower % target% upper % weight important re (%) maxim um 84.9 97.9 97.9 1 1 solution: results parameters : curren t density (ma/c m2) ph nacl additi on (g/l) re (%) fit df se. fit 95% ci 95% pi 25 7.8 3 98.3 67 1.0 0.642 (96.717,1 00.017) (95.869, 100.864 ) table 8-the optimum cod removal efficiency confirmation. n o current density ma/cm2 ph nacl ( g/l) u volt cod (ppm) re % ec. kwh/ kg cod in ou t actu al avera ge 1 25 7.8 3 4.64 73 5 21 97.1 4 97.33 5 30.91 4 2 25 7.8 3 4.64 72 8 18 97.5 3 31.09 3 25 7 3 4.58 75 0 38 94.93 30.60 1 table 9comparison between the wastewater effluent and the treated effluent. parameter effluent cod (ppm) ph turbidity (ntu) ec (ms/cm) cl (g/l) so4 -2 (g/l) raw effluent 735 7.9 9.66 1.89 1.56 0.6 treated effluent 21 7.8 2.36 14.6 1.7 2.5 the optimum conditions showed that the electrocoagulation process can be applied successfully for treating al-diwaniya hospital wastewater using iron electrodes. by starting from an initial cod (735 ppm), cod removal efficiency of 97.14% could be accomplished at 90 min electrolysis time. in this case, a specific energy consumption not more than 0.914 kwh/kg cod should be provided. in table 10, a comparison between the results of present work with the others related to hospital wastewater degradation by electrocoagulation process using iron electrode under various conditions have been achieved. based on this table, ec process is efficient and suitable for treating hospital wastewater with requesting only 90 min to remove approximately most of cod starting from cod of 735 mg/l with a suitable energy consumption related to previous works. table 10comparison of hospital wastewater treatments by electrocoagulation process using various type of electrodes under several conditions. type of wastewate r characterization of wastewater optimum conditions efficiency referenc e textile ph: 11.6, cod: 800mg/l, color: 401 mg/l, turbidity: 105 ntu,fe electrodes c.d.= 8 macm−2 ph= 7.1, t: 15 min color%=86% 82% turbidity cod%= 59% 46 hospital cod: 768 mg/l, ph:7.85, fe electrodes c=0.5a,nacl= 1.5 g/l, ph = 8.0,t = 120 min cod%=92.3% 47 hospital cefazolin: 42.3 pbb, cod: 528 voltage( 15 v), t: 30 min cod%=85% turbidity=94% 39 riham gh.najeeb, ali h. abbar /al-qadisiyah journal for engineering sciences 14 (2021) 000–000 141 mg/l, turbidity: 269 ntu, ph: 7, al electrodes cefazolin=94% hospital cod:398mg/l, turbidity: 186ntu, ph= 6.2-8.3, fe electrodes ph 3 , 30 v,60 min cod%= 87% 3 hospital cod: 807mg /l ph=8.1 fe electrodes ph=7.56, c.d.=4.87ma/c m2 cod%=99.11 % 28 hospital cod:735 ppm, turbidity:9.5nt u ph=7.8, fe electrodes initial ph: 7.8, c.d: 25 ma/cm2, nacl addition: 3 g/l. t=90 min cod%=97.14 % sec=(*) kwh/kgcod) present work 4. conclusions in the present study, electrocoagulation process as a green technology was applied for treating hospital wastewater generated from al-dewaniya hospital located at al-diwaniya city/south of iraq. experimental design was performed based on bbd with response surface methodology. rsm was used to assess the impacts of process factors and their interactions to achieve their optimum conditions. under the optimum operating conditions involving current density of 25 a/cm2, ph of 7.8,and nacl addition of 3 g/l ,the cod removal efficiency was found to be 97.14%. the results showed that a sensible operating cost of 30.914 kwh/kg cod was needed as energy consumption for cod removal from hospital wastewater. the proposed quadratic model was found to be fitted very well with the experimental data with r2 (98.18%). besides, results obtained in the present 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[44] c. núñez, j., yeber, m., cisternas, n., thibaut, r., medina, p&carrasco, “application of electrocoagulation for the efficient pollutants removal to reuse the treated wastewater in the dyeing process of the textile industry,” j. hazard. mater., vol. 371, pp. 705–711, 2019. article al-qadisiyah journal for engineering sciences 15 (2022) 055–066 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: rassolfatimi@gmail.com (rassol rasheed) https://doi.org/10.30772/qjes.v15i1.814 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. numerical investigation of the impact of various design parameters of finned-pipes on mixed convection rassol h. rasheed *, majid h. majeed and ahmed q. mohammed the technical engineering college, middle technical university, baghdad, iraq a r t i c l e i n f o article history: received 30 march 2022 received in revised form 28 may 2022 accepted 3 july 2022 keywords: mixed convection cfd enclosure ri finned pipes a b s t r a c t the mixed convection investigation of various design parameters utilizing finned pipes in the cylindrical enclosure has been investigated computationally. various geometries of fins are used (circular and longitudinal). the effect of fins number (12-16), aspect ratio (1.83-2.7), radius ratio (2-3) and fins geometry have been introduced within the present study. the observations show that when richardson number=0.5 and 5.5, the heat transfer decreases by 12.22% and 7.777%.,. values of the nusselt number rise as the number of fins increases. while, when the rayleigh number is high, no noticeable variations in the numbers of fins (12 and 14). the purpose of using fins is to increase the surface area of heat transmission. the highest heat transfer improvement is shown to be 4.2%, when log (rayleigh)=7.342 and 16 fins are utilized. the radius ratio does not affect nusselt number throughout the whole richardson and rayleigh in both hot and cold locales. the turbulence sub-layer does not affect the free stream behaviour for different richardson number. in the case of high richardson number, the geometry does not influence the nu. longitudinal fins do not have dead zones, unlike circular fins, which have channelling generated by geometrical arrangement. to reach thermal equilibrium in a cold environment, the nu in rectangular fins was reduced by 18% as compared to circular fins with a low richardson number. flow development would increase the impact of channelling. the heat transfer improvement decreases as the number of fins increases, as illustrated in temperature and velocity profiles for various values. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction a lid-driven cavity with mixed convection, which has been the focus of several scientific projects. this kind may be built using a mix of free and forced convection methods. in other words, when the buoyancy force is affected by the pumping force. also, every external element that affects the current flow is represented by the movement of one or more cavity walls, rotating the cylinder or other geometry inside the cavity, and finding the pump or fan. it is critical to discover an indicator of the relative magnitudes of convection when natural and forced convection interact. a dimensionless group (ri =gr/re2) offers a measure of the ratio of buoyancy force to inertial force in mixed convection flow in the cavity. the following three flow regimes inside the enclosure are distinguished using this criterion [1]. the mixed convection has been greatly used in electronic devices cooling, mixing process, hvac. numerous investigations dealt with http://qu.edu.iq/ mailto:rassolfatimi@gmail.com https://doi.org/10.30772/qjes.v15i1.814 https://doi.org/10.30772/qjes.v15i1.814 http://creativecommons.org/licenses/by/4.0/ 56 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15 (2022) 055–066 mixed convection due to it’s the vital role in the industrial and domestically uses such as: mansour et al. [2] investigated steady-state, laminar, and three dimensional objects mixed convection in a lid-driven cubical square cavity heated by its stationary lower wall. it was supposed that the top wall was chilly and going in the appropriate direction. the other walls were adiabatic. the findings were reported for (0.001< ri <10), with re=100 assumed to be the reynolds number constant. they concluded that increasing the richardson number improved the local nusselt number. the mixed convection flow between inner-heated circular cylinder moving effectively counter and a trapezoid container was described by khan, khan, & hasan, [3]. the trapezoidal enclosure's bottom and top sides were maintained adiabatic, while the two inclined walls were stored in the fridge. the impact of a static cylinder vs a moving cylinder in a square cage was compared. the revolving cylinder, as well as the inclination angle linked to sidewall effect, had a substantial impact on heat transmission, according to their results. faroogh and faraz [4] investigated numerically the natural mixed convection in a constant temperature square container comprising many pairs of hot and cold tubes using the simple algorithm based on the finite volume approach. the cylinder's surface has a stable temperature, while its walls are insulated and filled with nanofluid. the findings demonstrated that altering the rotational motion of the hot and cold cylinder can change the heat transfer rate. furthermore, altering the heat source/sink design from bottom top to top bottom dramatically reduces the heat transfer rate. in addition, the findings revealed that changing the orientation of the chilled cylinder from vertical to horizontal greatly reduces the number of screws. selimefendigil et al. [5] carried out numerical simulations of mixed convection in a rectangular channel with an adiabatic and rotating cylinder in the middle and 2 layers of nano-fluids and a porous medium. the bottom and top walls were heated and cooled separately. furthermore, the remaining left and right walls were insulated. the impacts of rayleigh number, nanoparticle size fraction, angular rotational velocity, darcy number ranging from, and different sizes and positions of the cylinder on fluid flow and heat transmission were investigated numerically using fea method. the effect of cylinder angular velocity on heat transfer enhancement was more pronounced for bigger cylinders. in all circumstances, the averaged heat transmission improved linearly as the volume fraction of the nanoparticle increases. the local and averaged nusselt numbers were increased as the cylinder approached the higher wall. in a lid-driven rectangular channel with centre trapezoidal frame, (gangawane & manikandan, 2017) [6] investigated 2d laminar mixed heat transfer for newtonian fluids. the left and right sides were cold; the top wall was flowing in the positive x direction, the top and bottom walls were both adiabatic, and all walls were fixed. it was concluded that raising (pr) improved heat transmission on the surface triangle. however, the heat transfer progressively increased when re=80-200 for the (0< gr< 103). hussein [7] investigated computationally the entropy production of time dependent mixed convection in a three-dimensional right-angle triangular cavity air filled. the hollow's perpendicular to the right side was heated and flowed toward the enclosure centre, downward, or towards the cold inclined wall. in contrast, the inclined left wall maintained stationary and represented the cold wall. the bottom wall had been repaired and was regarded as hot. the investigation looked at the richardson number, movement direction, and bejan number's impacts. the conclusion was that when (ri) grew, the mean nusselt number and entropy generation grew as well. zhang et al. [8] numerically investigated time dependent mixed convection in a 2d square enclosure with a concentric spinning circular cylinder. the container was completely devoid of air. the side walls had a cool temperature. the temperature in the cylinder surface was quite high. it was discovered that as the tangential velocity on the cylinder surface rose, the local nusselt number fell. mixed convection was explored in a 3d enclosure with two inner spinning circular tube loaded with nano-fluids by selimefendigil and oztop, 2018 [9]. the study was carried out using the finite element method. the left and right surfaces were heated and cooled, while the remaining walls and revolving cylinder were kept at room temperature. water was tested along with three different kinds of nanomaterials (tio2, cu, and al2o3). the results showed that utilizing cu-water nano-fluid at a high rayleigh number led to the highest rate of heat transmission. the rotating orientation of the cylinders had an impact on the average nusselt number. cu-water improved heat transmission by 38.10% compared to coolant fluid (water). abdul sahib and al-farhany [10] empirically explored the mixed convection in a square enclosure divided into two levels. the tests were carried out using an adiabatic rotating cylinder at the middle of the cavity and an al2o3–water nanofluid (upper layer) and superposed porous medium (bottom layer). the top and lower walls were adiabatic, the right wall was heated, and the left wall was chilled in the experimental investigation. when the concentration of nanoparticles is (0.06), the temperature differential (δt) between the cold and hot walls was (6, 8, and 10) °c, and the rotational velocity was (-50, 25, 0, 25, and 50) rpm. adding more, the temperature profile within the cavity was (6, 8, and 10 °c). the findings revealed that the effect of cylinder rotation was limited to the cylinder itself. furthermore, when the temperature gradient increases, the strength of the flow increases as well. hussein, hamzah et al. 2020 [11] computationally investigated mixed convection heat transfer between the inner circular spinning cylinder and the trapezoidal enclosure. furthermore, the space between the enclosure and the inner body was separated into two layers: the upper layer was filled with copper-water nano-fluid, while the bottom layer was filled with almost the same nano-fluids submerged in a saturated porous media. numerous non dimensional factors, such as darcy and rayleigh values, nanofluid voids percent, and many design parameters, such as undulations number of a bottom wavy wall, inner body diameter and rotating speed, and porous layer thickness, were investigated by the authors. the findings showed that increasing rayleigh, darcy, nano fluids voids percentage, and inner body diameter rotations led to a rise in average nusselt number, and thus improved heat transmission. el-shorbagy et al., [12]. on a suitable heat sink, the researchers numerically modelled the convective heat transfer of al2o3/cuo–h2o hybrid nano-fluids (hnfs) (hs). an isothermal hs carries the (hnfs) flow. on the upper wall, the nf stream was handled as a slip flow. the nf flow is influenced by a homogeneous magnetic field. to solve the algebraic problems, the control volume approach was combined with the simple algorithm. fin depth was varied between 0.1 and 0.3 for this purpose. furthermore, with four distinct layouts of fins for various thicknesses were studied. the results showed that dispersing a 3% volume of nanocomposites (nps) in water at a 1:1 ratio increased heat transfer by 2.78 % and entropy generation (seen) by 6.59 %, correspondingly. dispersing cuo nps were approved as having a high influence on the heat transfer improvement than al2o3 nps. at varying richardson numbers (ri), a change in together for or pattern resulted in differing behaviour. alshara e al., [13] experiential evaluation was carried out in 3d laminar mixed convective heat transfer coefficient from extended surfaces in a rectangular duct with slope. material of the lowest channel was exposed to a homogenous heat flow, while the other sides were isolated. in a various orientation rectangular duct, a series of empirical experiments for air flow with mixed convective heat transfer coefficient with longitudinal fins was performed. sloped orientations with perpendicular in the ranges of 075°. at various reynolds numbers (10002300) and the ranges of gasthof number (3x108-1x109). the study was developed to assess the influence of slope on local reference temperature, heat transfer rate, and mean heat transfer rate. the observations of the empirical analysis showed that optimal angle for maximal heat transmission is 45 degrees. the direction of the fin’s arrangement is also critical for improving heat exchange. rout et al., [14]. for a stable and laminar flowing fluid within a pipe under made by mixing flow regime, the temperature profile of a from within finned pipe rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15(2025) 055–066 57 has already been computationally calculated for different fin count, tallness, and structure by attempting to solve continuity equation of mass, dynamism, and energy utilizing fluent 12.1 for a stable and laminar flowing fluid within a pipe. it was discovered that the number of fins is vital to keep the tube wall temperature to a minimal value. the fin height tallness had an upper limit above which the temperature profile is unaffected by fin height. during mixed fluid flow, the top surface of a straight pipe had a greater mean temperature than the bottom part. the effect of fin form on the heat transfer rate demonstrates that pyramidal fins have the lowest thermal resistance relative to rectangularand tshaped fins. aside from the thermal properties, the pressure drop produced by the existence of fins had also been studied. kopeć and niezgoda-żelasko [15], the article's optimization estimates were relevant to longitudinally finned pipes of a hvac system evaporation working in natural steam outside air circulation circumstances. undulating fin form distinguishes the finned surfaces. the paper describes the methods used to find the best geometrical parameters of a finned tube, in which heat simulations were done using the numerical method that represent a convective heat transfer flow on the finned surfaces. the optimal solution was driven by the lowest mass of the fin, and hence design variables corresponded to the number of fins (n = 6), fin heights (h = 0.065), and fin depth (s = 0.0015 m) in the situation of maximizing heat input with least mass of a fin. the tubes with 10 fins with a length of h = 0.11 m and a depth of s = 0.0018 m permitted optimal heat input at the estimated mass of the fins inside the exchanger’s tubes design, according to optimization estimates for maximum efficiency of the exchangers at constant load. for any mass and optimum thermal performance, the article presents a simpler technique of estimating the ideal geometrical features of the contour. (dogan & seriola, 2010) [16] explored a wide variety of altered rayleigh numbers and varying fin height and distances, mixed convection transport via longitudinal fins on the inside of a horizontal. the effect of spacing, fin height, and heat flow intensity on mixed convective heat transfer coefficient using rectangular fin arrays warmed from underneath in a horizontal duct were investigated in empirical parameterized research. the best fin spacing for optimal heat transmission has been investigated. the constant heat parameter was achieved during the trials, and gas was employed as the coolants. when gas velocity solenoid valve was used, the speed of fluid exiting the duct was maintained virtually stable (0.15 0.16 m/s) such that the reynolds value was constantly around 1500. tests with altered rayleigh numbers 3x 107 8x 108 with richardson number 0.4 -5 were carried out. fin height was changed from hf/h = 0.25 to hf/h = 0.80, and non dimensional fin separation was adjusted from s/h = 0.04 to s/h = 0.018. the findings of an experimental investigation on mixed convective heat transfer coefficient showed that ideal fin separation for maximal heat transfer is s = 8–9 mm, and the optimal fin separation is dependent on the amount of ra*. (mishra, 2016) [17] this research focused on the computational model of a tube having inner fins that is exposed to mixed convection and undergoes natural and forced rate of heat transfer. s. the effect of several factors such as fin height, fin shape (rectangular, t-shaped triangular), heat flux, reynolds number, and tube inclination (horizontal and vertical) on tube temperature rise has been investigated. it has been discovered that heat transmission is considerable for triangular fins, and that heat transfer is greater in perpendicular direction due to the buoyancy and boundary layer heat exchange than in parallel configuration. the collected data were compared to existing publications and found to be acceptable agreement. (al-taha, osman, & majeed) [18], in 2017, the enhancement of heat transmission capacity when these interfaces were curved and disrupted, as in undulating fins, pinned fins, slot and holed fins, is of particular interest. the problem of heat transmission for perforation fins under forced convection has been the focus of this paper. the thermal efficiency was investigated for a set of rectangle fins implanted with various vertical body perforation patterns that run the length of the fin thickness. perforation (circular, square, rectangular) and enlarged fin were amongst the designs. the extent to which the hole improved the transfer rate relative to the corresponding traditional fin was investigated. when square and circular hole patterns were similar in perforation area, the fin with rectangular holes demonstrates a larger heat transport increase (16 % of non-perforated) (24cm2). the fin having square holes had a greater heat transfer enhancement (13 % vs. non-perforated) than the fin with circular holes, which had roughly the same heat transfer performance (11 % of nonholed). due to temperature drop, the effectiveness of the perforation fin was lower than that of non-perforated fin (82 97 % of non-perforated). on the other hand, as long even as thermal transfer rate ratio was more than unity, the efficacy of the holed fin is better than those of the non-holed fin (1080% of non-holed). retractable fins were very well being in great demand. considerable weight loss (66-96 % of non-perforated) was shown, because both the surface and the heat transfer rate were increased at almost the same moment. the present work is aimed to investigate numerically the mixed convection inside a cylindrical enclosure. in addition, to study the effect of various design parameters such as: fins number, aspect ratio, radius ratio and fins geometry on nusselt number. finally, observing the parametric behaviour in heat transfer performance in current system by generating the temperature and flow contours. 2. the theoretical aspect the cylindrical enclosure is used to place four pipes with equal distances from the canter. two of these pipes are subjected to a uniform heat power while the others are subjected to the ambient temperature from the interior surface. many parameters such as rayleigh number is used for various distances, orientations, fins numbers, fins size, fins type in free convection additional to richardson number in mixed convection case. the geometries are presented in figure 1. the assumptions are placed by modifying the geometry coordinate, physics conservation equations, boundary conditions and study pattern. for the present investigations, the assumptions are summarized as following: 1. steady state models. 2. the geometry coordinate is three dimensions with constant surface area and symmetric with finite slides with perpendicular direction. 3. the boundary walls are nonslip conditions. 4. the fluid flow is laminar. 5. constant physical properties except the density variation with temperature (bossiness approximation) and pressure. 6. the radiation effect and the energy dissipations had been neglected. the main applied physics in present work are momentum transport (turbulent k-𝜀) and heat transfer through fluid and solid. the complex partial differential equations are converted into algebraic equations based on force balance and heat balance with control system by mean of mesh distribution. the multiphysics coupling is enabled by interaction between velocity and temperature distribution. the velocity components are used for convection purpose in heat transfer equation while the temperature can manipulate the physical properties which are polynomial expressions. the following conservation equations are used for momentum: -momentum equation 𝜌(𝑈. ∇)𝑈 = ∇. (−𝜌𝐿 + 𝐾) + 𝐹 + 𝜌 (1) -continuity equation 58 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15 (2022) 055–066 ∇. (𝜌𝑈) = 0 (2) -kinetics expressions 𝐾 = (µ + µ𝑡 )(∇𝑈 + (∇𝑈) 𝑇 ) − 2 3 (µ + µ𝑡 )(∇𝑈)𝑙 − 2 3 𝜌𝑘𝑙 (3) 𝜌(𝑈. ∇)𝑘 = ∇. [(µ + µ𝑡 𝛿𝑘 ) ∇𝑘] + 𝜌𝑘 − 𝜌£ (4) 𝜌(𝑈. ∇)£ = ∇. [(µ + µ𝑡 𝛿£ ) ∇£] + 𝐶£1 £ 𝑘 𝜌𝑘 − 𝐶£2 𝜌 £2 𝑘 (5) µ𝑡 = 𝜌 𝐶µ𝑘 2 £ (6) 𝜌𝑘 = µ𝑡 [∇u: (∇u + (∇u) t) − 2 3 (∇. u)2] − 2 3 ρk∇. u (7) where: the k£ turbulent model constants which are derived from comsol software for general fluid, c£1=1.33, c£2=1.92, cµ=0.09, δk=1 and δ£= 1.3. for heat conservation, following equation is used: -heat equations 𝜌𝐶𝑝𝑈∇𝑇 + ∇. 𝑞 = 𝑄𝑠𝑢𝑚 (8) 𝑞 = −𝜁 ∇𝑇 (9) -calculate the inlet velocity from the expression bellow 𝑈 = 𝑔 𝛽 (𝑇ℎ−𝑇∞)𝐿 𝑅𝑖 (10) to design the longitudinal fins which have the equivalent surface area of circular fins. defining the surface for each one is needed. the circular fins surface area [19-20]: 𝑆1 = 𝑛[2 𝜋(𝑅2 2 − 𝑅1 2) + 2𝜋𝑅2 𝑡] (11) the longitudinal fins surface area: 𝑆2 = 4[2 𝑡 𝑤 + ℎ 𝑡 + 2 ℎ 𝑤] (12) a. circular finned b. without fin c. longitudinal finned pipe figure 1. geometrical configuration. (a) circular fin (b) longitudinal fin figure 2. fins characteristics dimensions. let s1=s2 𝑛[2 𝜋(𝑅2 2 − 𝑅1 2) + 2𝜋𝑅2 𝑡] = 4[2 𝑡 𝑤 + ℎ 𝑡 + 2 ℎ 𝑤] 2 𝜋 𝑛[(𝑅2 2 − 𝑅1 2) + 𝑅2 𝑡] = 4[2 𝑤 (𝑡 + ℎ) + ℎ 𝑡] then: 𝑤 = 2 𝜋 𝑛[(𝑅2 2−𝑅1 2)+𝑅2 𝑡]−4 ℎ 𝑡 8 (ℎ+𝑡) (13) rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15(2025) 055–066 59 applying of conservation equations of mixed convection system needs to set up the appropriate boundary conditions such as: inlet flow: velocity inlet (from top). outlet pressure: from bottom. constant pipe inner surface heat flux surface. isotherm cold pipe inner surface temperature. wall function for interior (pipes walls) and exterior walls (enclosure walls, u=0). inlet temperature: the temperature of inlet fluid. where the w is manipulated by the number of circular fins and the outer length of the circular fins (radius ratio r). the various parameters are taken in considerations through the present work investigation: aspect ratio (as): is the ratio between the enclosure diameter to the diagonal distance between the pipes. radius ratio (r): is the ratio of fins radius to pipe radius. richardson number: is the ratio of gr to re2, (ri=gr/re2). 3. results and discussion 3.1. the effect of richardson number without fins case figures 3 and 4 show nu vs. log ra for various ri whereas=1.83 for cold and hot pipes regions. the increase of ri drops the nu values significantly for both hot and cold regions. the high values of ri promote the free convection mechanism while the lower ri makes the heat transfer turns toward the forced convection. the ri is considered the main criteria for heat transfer behaviours when the mixed convection is performed inside the enclosure. in the observations in fig.3 show that he heats transfer from a hot surface to a bulk fluid is 40 % higher than the heat transfer from a cold surface to a bulk fluid. this is because the heat transfer contact period duration in the hot zone is longer than the cold region. 3.2. the effect of aspect ratio figures 6 and 7 show nusselt number vs. rayleigh number for various as in smooth two heat pipes in both hot and cold surfaces. in the hot pipe region, the nu values increase by increasing as the 11.11 % heat transfer enhancement is observed at ri=0.5 and 20.8 % is observed at ri=5.5. in cold pipe region the opposite behaviour to hot pipe region is observed. the heat transfer performance is shown to decrease when the aspect ratio increasing. the heat transfer decreased by 12.22 % and 7.777 % for ri=0.5 and ri=5.5 respectively. the rising of aspect ratio generates higher volume mixing between the hot pipe region and free stream. while the lower mixing intensity between the cold region fluid volume with the free stream (film temperature region). figure 3. nusselt number vs. rayleigh number for various ri, as=1.83, without fins in hot pipe region. figure 4. nusselt number vs. rayleigh number for various ri, as=1.83, without fins in cold pipe region. figure 5. nusselt number vs. rayleigh number, as=1.83, without fins in both hot and cold pipe regions. figure 6. nusselt number vs. rayleigh number for various aspect ratio, without fins in hot pipe region. 30 280 530 780 1030 1280 1530 1780 7.5 7.6 7.7 7.8 7.9 8 8.1 n u log(ra) hot pipes ri= 0.5 ri= 1 ri= 2 ri= 3.5 30 530 1030 7.2 7.4 7.6 7.8 8 8.2 n u log(ra) cold pipes ri= 0.5 ri= 1 ri= 2 ri= 3.5 ri= 5.5 0 200 400 600 800 1000 1200 7.4 7.6 7.8 8 8.2 n u log(ra) hot cold 0 500 1000 1500 7.4 7.6 7.8 8 8.2 n u log(ra) hot pipes as=1.83 ri= 0.5 as=1.83 ri= 5.5 as=2.7 ri= 0.5 as=2.7 ri= 5.5 60 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15 (2022) 055–066 3.3. the effect of fins number (circular fins) hot pipe nusselt number vs. rayleigh number for various circular fins numbers is shown in figure 8. in high ra, the range of nu values grow as the fins number increases, with no notable changes for the lower numbers (12 and 14). the rising of ri decreases the nu, the behaviour in this case is approximately similar to the case of without fins. the heat transfer of hot region is higher than the cold region approximately by 40 % for whole ra and ri. the increase of ri is higher than ri=0.5 case. the sharp decrease of nu occurs for furthermore ri the decreasing in nu is low decreasing sharply. cold pipe nusselt number vs. rayleigh number for various circular fins numbers is shown in fig 9. similarly, nu range values grow as fins number increases, with no noticeable modifications for smaller numbers (12 and 14) in high ra conditions, such as the hot side. when log (ra)=7.34 and 16 fins are used, the maximum heat transfer improvement is shown to be 4.2 %. the difference in nu behaviour between hot and cold pipes is clear, with the number of fins having a greater impact on the nu. 3.4. the effect of radius ratio, r, (circular fins) nusselt number vs. rayleigh number for varied r in as=1.83, 12 fins, and both hot and cold zones are shown in figures 10 and 11. throughout both hot and cold locations, the radius ratio has shown no influence on nu for the whole ri and ra. for varied ri, the turbulence sub-layer has no influence on the free stream behaviour. for a single ri, the whole plot in the cold zone has values that are relatively close. when the fluid flow subjects the current system, the dead zone heat transfer rises, which eliminates the heat transfer enhancement caused by boundary layer destruction. 3.5. the effect of aspect ratio (as) (circular fins) figures 12 and 13 show the nusselt number vs. rayleigh number in various as, r=2 and 12 circular fins for both hot and cold pipe regions. the nu increases by increasing the as in hot pipe region and decreases by increasing as in cold pipe region. the heat transfer system needs the integration between the hot and cold regions heat transfer with the free stream to achieve the thermal equilibrium. in other words, the amount of nu number increases directly with as needs the reverse behaviour with as in cold region to achieve the thermal equilibrium. the temperature difference between cold region and free stream increase by reducing the temperature difference between hot surface and free stream. geometries with smooth pipe for various ri and both hot and cold heat pipe regions. the longitudinal fins have maximum nu above the circular fins and without fins case by 12 % for low ri. the geometry has shown no significant effect on the nu when ri is high. the dead zones are not presented in longitudinal fins unlike the circular fins which the channelling is formed due to geometrical configuration. for the cold region, the nu decreases by 18 % in rectangular fins compared with circular fins in low ri number to achieve the thermal equilibrium. the high ri makes the geometry has no significant effect on nu. the inertial force due to the turbulent flow development is the main mechanism which is applied within the present system in general. the resultant inertial force is higher than the volume force (resulted from the gravity and density gradient). unlike the density difference force, the geometry of fins has no great impact on heat transfer performance where the high inertial force is presented. figures 14 and 15 show the nu vs. log ra for various fins. figure 8a. nusselt number vs. rayleigh number at ri=0.5 and various fins number in hot pipe region. figure 8b. nusselt number vs. rayleigh number at ri=2 and various fins number in hot pipe region. 60 260 460 660 860 1060 1260 1460 1660 1860 7.6 7.8 8 8.2 8.4 8.6 n u log (ra) hot pipe 12 fins ri=0.5 14 fins ri=0.5 16 fins ri=0.5 60 160 260 360 460 560 660 760 860 7.6 7.8 8 8.2 8.4 8.6 n u log (ra) hot pipe 12 fins ri=2 14 fins ri=2 16 fins ri=2 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15(2025) 055–066 61 figure 8c. nusselt number vs. rayleigh number for ri=2 and various fins number in hot pipe region. figure 9a. nusselt number vs. rayleigh number for ri=0.5 and various fins number in cold pipe region. figure 9b. nusselt number vs. rayleigh number at ri=2 and various fins number in cold pipe region. figure 9c. nusselt number vs. rayleigh number for ri=5.5 and various fins number in cold pipe region. 60 160 260 360 460 560 660 7.6 7.8 8 8.2 8.4 8.6 n u log (ra) hot pipe 12 fins ri=5.5 14 fins ri=5.5 16 fins ri=5.5 60 260 460 660 860 1060 1260 1460 1660 1860 7.6 7.8 8 8.2 8.4 8.6 n u log (ra) cold pipe 12 fins ri=0.5 14 fins ri=0.5 16 fins ri=0.5 60 160 260 360 460 560 660 760 860 7.6 7.8 8 8.2 8.4 8.6 n u log (ra) cold pipe 12 fins ri=2 14 fins ri=2 16 fins ri=2 60 110 160 210 260 310 360 410 460 510 7.6 7.8 8 8.2 8.4 8.6 n u log (ra) cold pipe 12 fins ri=5.5 14 fins ri=5.5 16 fins ri=5.5 62 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15 (2022) 055–066 figure 10. nusselt number vs. rayleigh number at ri=0.5 and various r in hot pipe region. figure 11. nusselt number vs. rayleigh number for ri=0.5 and various r in cold pipe region. figure 12. nusselt number vs. rayleigh number for various ri and as in hot pipe region. figure 13. nusselt number vs. rayleigh number for various ri and as in cold pipe region. 850 950 1050 1150 1250 1350 1450 7.4 7.5 7.6 7.7 7.8 7.9 n u log (ra) hot pipe r=2 ri=0.5 r=2.5 ri=0.5 r=3 ri=0.5 500 550 600 650 700 750 800 850 900 950 1000 7.4 7.5 7.6 7.7 7.8 7.9 n u log (ra) cold piper=2 ri=0.5 r=2.5 ri=0.5 r=3 ri=0.5 0 500 1000 1500 2000 2500 7.4 7.6 7.8 8 8.2 8.4 n u log (ra) hot pipe as= 2.7 ri=0.5 as= 2.7 ri=5.5 as= 1.83 ri=0.5 as= 1.83 ri=5.5 0 200 400 600 800 1000 1200 1400 1600 1800 2000 7.4 7.6 7.8 8 8.2 8.4 n u log (ra) cold pipe as= 2.7 ri=0.5 as= 2.7 ri=5.5 as= 1.83 ri=0.5 as= 1.83 ri=5.5 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15(2025) 055–066 63 figure 14. nusselt number vs. rayleigh number for various ri and fins geometries in hot pipe region. figure 15. nusselt number vs. rayleigh number for various ri and fins geometries in cold pipe region. 3.6. the contour analysis the more warmed surface is getting to be red, and the cold surface prevails the blue colour as shown in legend bar. figure16 shows the contour analysis (velocity and temperature) of mixed convection; circular finned pipe is used as heated pipe. the increase of fins number growths the attributing of flow inside the enclosure. the effect of channelling would be maximized by flow development. the maximum numbers of fins, the heat transfer enhancement decreasing is occurred. 12 fins 14 fins 16 fins figure 16. contour analysis of mixed convection of circular finned pipe of various fins number. 0 500 1000 1500 2000 2500 3000 7.4 7.5 7.6 7.7 7.8 7.9 8 n u log (ra) hot pipe circular fins ri=0.5 circular fins ri=5.5 longitudal fins ri=0.5 longitudal fins ri=5.5 without fins ri=0.5 without fins ri=5.5 60 560 1060 1560 2060 2560 7.4 7.6 7.8 8 n u log (ra) cold pipe circular fins ri=0.5 circular fins ri=5.5 longitudal fins ri=0.5 longitudal fins ri=5.5 without fins ri=0.5 without fins ri=5.5 312 298 64 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15 (2022) 055–066 as=1.83 as=2.7 figure 17. contour analysis of mixed convection of circular finned pipe of various as. figure 17 shows the contour analysis (velocity and temperature) of mixed convection; circular finned pipe is used as heated pipe of various as. the increase of aspect ratio enhances the heat transfer between the cold fluid flow and the heated surfaces. the increase of as promotes low thermal resistance due to the increase of the velocity distribution inside the enclosure which makes the tendency of high mixing overcoming the viscous effect. figure 18 shows the contour analysis (velocity and temperature) of mixed convection; circular finned pipe is used as heated pipe of various r. the increase of r enhances the heat transfer between the cold fluid flow and the heated surfaces. the increase of r promotes the heated transfer area providing high dissipation of hot temperature and velocity to bulk fluid through the fluid flow for various ri. figure 19 shows the contour analysis (velocity and temperature) of mixed convection; finned pipe is used as heated pipe for various fins geometries. the rectangular fins have the same surface area of circular fins. the higher rate of fluid volume mixing (hot and cold) is presented within longitudinal fins more than the circular. the channelling effect is negligible at rectangular fins for equivalent surface area. figure 20 shows the contour analysis (velocity and temperature) of mixed convection; longitudinal finned pipe is used as heated pipe of various r. r=2 r=2.5 r=3 figure 18. contour analysis of mixed convection of circular finned pipe of various r. the increase of r is shown to improve the hot fluid transports through the bulk fluid. the higher r provides the significant higher surface area with minimum channelling effect. 312 298 312 298 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15(2025) 055–066 65 (a) (b) (c) (d) (e) (f) figure 19. contour analysis of mixed convection of finned pipe of various fins geometries. a) circular finned pipe of 12 fins, b) rectangular finned pipe of equivalent 12 fins, c) circular finned pipe of 14 fins, d) rectangular finned pipe of equivalent 12 fins, e) circular finned pipe of 16 fins, f) rectangular finned pipe of equivalent 16 fins. . figure 21 shows the comparison between the present work and bard, 1983 [19]. mixed convection of two heaters where hot pipe was used and ri=0.5. the results showed good agreement with previous work investigation with corresponding of 14 % as a maximum error. 4. conclusions the numerical investigation of mixed convection inside the cylindrical enclosure in presence and absence of fins has been investigated. the increase of ri decreases the nu significantly for both hot and cold regions. the high values of ri promote the free convection mechanism while the lower ri makes the heat transfer turns toward the forced convection. the ri is considered the main criteria for heat transfer behaviours when the mixed convection is performed inside the enclosure. in the hot pipe region, the nu values increased by increasing the as 11.11 % heat transfer enhancement is observed at ri=0.5 and 20.8 % is observed at ri=5.5. r=2 r=2.5 figure 20. contour analysis of mixed convection of rectangular finned pipe of various r. figure 21. the validation with previous work [19] 0 200 400 600 800 1000 1200 1400 7.4 7.5 7.6 7.7 7.8 7.9 n u log(ra) present work badr, 1983 312 298 66 rassol h. rasheed et al. /al-qadisiyah journal for engineering sciences 15 (2022) 055–066 in the cold pipe region, the opposite behaviour to the hot pipe region is obtained. the heat transfer performance is decreased when the aspect ratio increases. the heat transfer decreased by 12.22 % for ri=0.5 and 7.777 % for ri=5.5. in high ra, the nu range values grow as the fins number increases, with no notable changes for the lower numbers (12 and 14). the effect of fins primarily serves as a measure of heat transfer surface area. when log (ra)=7.342 and 16 fins are used, the maximum heat transfer improvement is 4.2 %. throughout both hot and cold locations, the radius ratio has no influence on nu for the whole ri and ra. for varied ri, the turbulence sub-layer does not influence the free stream behaviour. for a single ri, the whole plot in the cold zone has relatively close values. the nu increases by increasing the as in the hot pipe region and decreases by increasing as in the cold pipe region. the heat transfer system needs the integration between the hot and cold regions heat transfer with the free stream to achieve thermal equilibrium. in other words, the amount of nu number increases directly with as needs the reverse behaviour with as in cold region to achieve the thermal equilibrium. the geometry has no significant effect on the nu for high ri. the dead zones are not presented in longitudinal fins, unlike the circular fins in which the channelling is formed due to geometrical configuration. for the cold region, the nu decreases by 18 % in rectangular fins as compared with circular fins in low ri number to achieve thermal equilibrium. the effect of channelling would be maximized by flow development. the maximum number of fins, the heat transfer enhancement decrease happens as shown in temperature and velocity profiles for various parameters. references [1] garbrecht o, kabelac s, kneer r. large eddy simulation of three-dimensional mixed convection on a vertical plate. lehrstuhl für wärme-und stoffübertragung; 2017. [2] mansour nb, ben-cheikh n, ben-beya b, lili t. mixed convection of heat transfer in a square lid-driven cavity. international letters of chemistry, physics and astronomy. 2015;55:181. [3] khan m, khan aa, hasan mn, editors. numerical study of mixed convection heat transfer from a rotating cylinder inside a trapezoidal enclosure. aip conference proceedings; 2016: aip publishing llc. [4] garoosi f, hoseininejad f. numerical study of natural and mixed convection heat transfer between differentially heated cylinders in an adiabatic enclosure filled with nanofluid. journal of molecular liquids. 2016;215:1-17. [5] selimefendigil f, ismael ma, chamkha aj. mixed convection in superposed nanofluid and porous layers in square enclosure with inner rotating cylinder. international journal of mechanical sciences. 2017;124:95-108. [6] gangawane km, manikandan b. mixed convection characteristics in lid-driven cavity containing heated triangular block. chinese journal of chemical engineering. 2017;25(10):1381-94. [7] hussein ak. entropy generation due to the transient mixed convection in a three-dimensional right-angle triangular cavity. international journal of mechanical sciences. 2018;146:141-51. [8] zhang w, wei y, dou h-s, zhu z. transient behaviors of mixed convection in a square enclosure with an inner impulsively rotating circular cylinder. international communications in heat and mass transfer. 2018;98:143-54. [9] selimefendigil f, öztop hf. mixed convection of nanofluids in a three dimensional cavity with two adiabatic inner rotating cylinders. international journal of heat and mass transfer. 2018;117:331-43. [10] abdulsahib ad, al-farhany k. experimental investigation of mixed convection on a rotating circular cylinder in a cavity filled with nanofluid and porous media. al-qadisiyah journal for engineering sciences. 2020;13(2):99-108. [11] hussein ak, hamzah hk, ali fh, kolsi l. mixed convection in a trapezoidal enclosure filled with two layers of nanofluid and porous media with a rotating circular cylinder and a sinusoidal bottom wall. journal of thermal analysis and calorimetry. 2020;141(5):2061-79. [12] el-shorbagy m, algehyne ea, ibrahim m, ali v, kalbasi r. effect of fin thickness on mixed convection of hybrid nanofluid exposed to magnetic field-enhancement of heat sink efficiency. case studies in thermal engineering. 2021;26:101037. [13] alshara ak, abood fa, shrama sm. an experimental investigation of mixed convection from a finned wall in an inclined rectangular duct. [14] rout sk, mishra dp, nath thatoi d, acharya ak. numerical analysis of mixed convection through an internally finned tube. advances in mechanical engineering. 2012;4:918342. [15] kopeć p, niezgoda-żelasko b. optimisation of the geometric parameters of longitudinally finned air cooler tubes operating in mixed convection conditions. processes. 2021;9(1):111. [16] dogan m, sivrioglu m. experimental investigation of mixed convection heat transfer from longitudinal fins in a horizontal rectangular channel. international journal of heat and mass transfer. 2010;53(9-10):2149-58. [17] mishra jkagas. computational analysis of mixed convection of internal finned tube. international journal of engineering research & technology. 2016;8. [18] al-taha wh, osman ha, majeed mh. enhancementof forced convection heat transfer from rectangular fin with different forms of perforation. [19] bard, h. m., 1983, "a theoretical study of laminar mixed convection from a horizontal cylinder in a cross stream," international journal of heat and mass transfer, vol. 26, pp. 639-653. [20] holman j. p., “heat transfer”, crc press, london , 2010. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� analysis of water hammer for al-kut water supply project using the method of characteristics hussein shakir mahmud al-bahrani environmental engineering m. sc. engineering collegeuniversity of kufa abstract in this study, a mathematical model have been prepared for al – kut water supply project depending upon the numerical methods such as newton raphson method and gaussian elimination method to solve non – linear simultaneous equations with known boundary condition and by using the characteristic method, the partial differential equations are transformed to ordinary differential equations. in this mathematical model, the values of the generated pressures were calculated when using control devices or without, also, to find the influence of this devices on, the pressure values was found. in addition to, the suitable number of control devices required for each pipeline was found to keep the pressure values within a tolerable limits. this model was applied on a published case study and the results were quite satisfactory. key words: water hammers method of characteristics ��&���� �� ��� � '�( ���)� ������� �*� +��"�!�� �,�� -�� ���!. /� 0�� 12����� 3�� )��� ���)� ,�0 ��!) ��&�� �!��' ��!��� �!����� ���,–�4�,�� ����� �$�"�� � :�� ?��@�� =�" ����� 7��� ����a � ��� ��b �> 5���(� c���( ���$�� d���� e$�� �$�!��� f��� ���� –� ��!>�� c��� ���� �� ���@��� 5( �� ���� ��"�� ��g � h� ����$��� # � i� � j��( .� 5��"�!�� �*� �2����� ������� ������� � ��%� ����$� ��� �.9��� � ��%��� ����$��� #�� � 5� . al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� �c�5� �������� ��k��� 5�2 ����a 7��� �� ��b �> �� �>� 5��"�!� �� �>"�!� 5�� � ����!�� �9��� 5�� l 3� �b��� ��� ��k��� 5�2 � � l>� ��� �(�� �(� �9���� m�b �� n!� ��� ��$�� 5��"�!�� ��k��� 5�2 � � �b����� o�� ��!���.�� c����� p.�� �� �:�� �� ���@ � ��!� � � qc����� 7��� �� ��b �� dc ��� 5� . nomenclature a area of pipe a velocity of propagation of fluid transients c1 parameter that describes the effect of pipe constraint condition on the wave speed cn, cp constants in characteristic equation d diameter of pipe e modulus of elasticity (pipe wall) e pipe wall thickness f() pressure wave travelling in the -x direction in the pipe f() pressure wave travelling in the +x direction in the pipe f darcy-weisbach friction factor g gravitational acceleration h instantaneous pressure head h0 steady-state pressure head ht ∂h/∂t; partial derivative hx ∂h/∂x; partial derivative hv head losses k bulk modulus of elasticity (fluid) l length of pipe p instantaneous pressure p0 steady-state pressure pt ∂p/∂t; partial derivative px ∂p/∂x; partial derivative q steady state pipe line discharge t time v instantaneous velocity of flow v0 steady-state velocity of flow vt ∂v/∂t; partial derivative vx ∂v/∂x; partial derivative x distance along the pipe measured from upstream end z elevation above datum α pipe slope μ poisson's ratio ρ density of fluid ζ head loss coefficient (valves, orifices) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� introduction early work of several mathematicians and physicists has been concerned with the speed of propagation of pressure waves in two distinctive fields by thorley in 1976 [streeter (1993)]: one was an elastic medium in a rigid pipe, the other of an incompressible fluid in an elastic pipe. korteweg in 1878 was the first to develop an equation for the wave speed in a compressible fluid contained in an elastic pipe. but this early work was not concerned with pressure and velocity variations in pipes. probably the first reported analytical treatment of pressureand flow-variations was that of frizell in1898, a consulting engineer for a hydroelectric power development. joukowsky in 1900 conducted the first comprehensive series of experiments on a large-scale system, which he supported with an analytical treatment. the experiments were made in cast iron pipes (diameters 2", 6", and 24") of the moscow water works in 1897/1898. the work of joukowsky represents a milestone in the history of water hammer. his conclusions formed the basis of much later work. they were: 1. the pressure wave is transmitted through the pipe at a constant speed, the value of which depends upon the pipe dimensions, the elastic modulus of the pipe wall material, and the bulk modulus and density of the fluid. 2. the amplitude of the pressure wave traveling along a uniform pipe remains constant. 3. the concept of transmitted and reflected waves completely explains the periodic nature of the pressure recordings. 4. a pressure wave is reflected from an open-ended pipe with constant pressure. 5. pressure changes are doubled by reflection at a dead end. 6. air chambers are an effective method of preventing excessive pressure rise. 7. the pressure diagram can be used as a source of information about the conditions in the pipe, e.g. sites and mass of entrapped air, sites of heavy in iraq, reyad zuhair was one of the first researchers who work on the water hammer using the characteristics method at one pipe at baiji water pipe line (zuhair, r, 1987). then, abd alabbas came later and work on the water hammer using the same method but at four pipes at najaf –kufa water supply project (abd al-abbas, f, 2000). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� water-hammer/ transient flow the intermediate – stage flow, when the flow conditions are changed from one steady conditions to another steady state is called transient state flow, in other words, the transient conditions are initiated whenever the steady – state condition are disturbed. common examples of the cases of transients in engineering system are: opening or closing of valves in a pipeline, power failure to pumps, action of reciprocating pumps, starting up a hydraulic turbine, vibrations of the vans of a runner or the blades of a fan, and waves on a reservoir water surface [roberson et. al (1998), streeter (1971), and streeter and wylie (1993)]. the terms water hammer or transient flow refer to those unsteady flow situations where the change in the motion of the fluid is comparatively rapid and the time for the forcing conditions to change is short compared to the time taken for a wave of pressure to pass through the fluid column. the behavior of the pressure transients is governed by the inertia of the moving water and the combined elasticity of the water and the pipe system. in general both, inertia and elasticity, must be considered, which requires compressible flow theory. depending on the complexity of the task, the graphical method or characteristics method may be used [larreteguy et. al,(2005)]. 1basic equations for pressure transients the general derivation of the partial differential equations for the unsteady flow of liquids in slightly elastic pipes is based on the principle of conservation of mass and momentum. both, the equation of motion and the continuity equation are developed regarding an elemental control volume. once a transient has been generated and propagated along a pipe, its subsequent behavior depends on the boundary conditions of the particular system. therefore the actual boundary conditions are an important part for the investigation of pressure transients in hydraulic systems. there are different forms of both equations that are used when investigating pressure transients. one of the common forms will be presented at first and simplified forms of the equations will follow [wylie (1983)]. 1.1 equation of motion (momentum equation) this equation is governing the transient state condition. applying the low of conservation of mass to a fluid element within a pipe of a cross sectional area (a) and length (dx) [white (1991)] ghx + vvx + vt + fv|v| /2d = 0 [2.1] al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� this equation must be valid also for steady flow, a special case of unsteady flow. by setting vx = 0 and vt = 0 it becomes ∆h = f(∆x/d)(v2/2g) which is the darcy-weisbach equation. 1.2 continuity equation it may be applied the low of conservation of mass to a control volume yields to device the continuity equation [white (1991)] vhx + ht vsinα + (a 2 /g)vx = 0 [2.2] where the wave speed “a” is considered to be a constant depending on the properties of the fluid, the pipe and its means of support: a 2 = (k/ρ)/(1 + ((k/e)(d/e))c1 [2.3] three support situations for a thin-walled pipeline may be regarded: i pipe anchored at its upstream end only c1 = 1 µ/2 ii pipe anchored throughout against axial movement c1 = 1 -µ² iii pipe anchored with expansion joints throughout c1 = 1 the value of poisson's ratio μ for steel is close to 0.3. it should be noticed that a very small amount of entrained gas in the fluid causes much greater change in the wave speed than the effect of μ.the two basic equations, which govern the behavior of pressure transients in liquids in slightly deformable pipes contain four variable quantities, (x, t) as independent variables and (h, v) as dependent variables. for unsteady flow situations this means that the pressure and the velocity of flow in a system depends on both, position in the system and time. methods for solving continuity and momentum equations the momentum and continuity equations are quasi – linear, hyperbolic, partial deferential equations. a closed form for solution of these equations is not available. however, neglecting or al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� linearizing the non-linear equations has developed linear terms, various graphical and analytical methods [parmakian (1963) and smith (1978)]. these methods are approximate and can not be used to analyze large systems or systems having complex boundary conditions. the arithmetic method neglects the friction term and assumes that the pipe is horizontal. this method is consider simple theoretical development but has iterative calculations and tedious operations [smith (1978)]. the impedance method is suitable for digital computer analysis only, because of the lengthy algebraic equations involved. the transfer matrix method has been used for analyzing structure and mechanical vibrations, and for analyzing the electric system. this method was introduced by many authors such as chaudhry as a method for analyzing the transient state. the transfer matrix is derived by a numerical procedure is presented by chaudhry [chaudhry (1987) and roberson et. al (1998)]. similar to the impedance method, the transfer method is based on the linearized equations and on sinusoidal flow and pressure fluctuation. however, both methods are restricted for special case of the transient flow that called "steady – oscillatory flow". the algebraic method transforms the characteristics method equations into a from in which the time is subscript. this method has the advantage that the characteristics equations may be applied over one or more reach of a pipe are applied. the disadvantage of this method is that the friction term is not handled so accurately when more than one reach is covered by an equation. more details of the algebraic method may be found in streeter [streeter and wylie (1988)]. analytical methods are assumed that the true friction loss approximate to the first power of velocity, i.e., linearizing the non – linear term, or this term may be ignored. this method includes very difficult mathematical operation, hence it can not be used for a complex system. the graphical method assumed that the head loss along the pipe is approximated by placing hypothetical obstruction at selected locations along the pipeline, with the friction head loss along the pipe concentrated at these location. the accuracy of this method increases by the number of obstructions, leading to increase complexity. in the finite difference method, the partial derivatives are replaced by finite – difference approximations and the resulting equations are solved simultaneously [chaudhry (1979), and streeter and wylie (1988)]. the analysis by finite difference method become more complex by increasing the complexity of the system. because of computer, requirements become more and in a large system, a large number of equations must be solved which requires large amount of computing time. the method of characteristics utilized a special property of hyperbolic partial differential equations to find their numerical solutions. for a system having such equations, there are two characteristics directions in al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � the (x-t) plane in which the integration of the partial differential equations is reduced to the integration of a system of ordinary differential equations. the advantages of this method are that, it is a method of solution, which allows the direct inclusion of friction losses, if, offers ease in handling the boundary conditions and in programming a complex system. it is a general method, i.e., the program, once written, may be used for analyzing any piping system having the same boundary conditions, and the transient state conditions obtained by using this method are close to the actual situation. the only restriction in this method is that flow must be one-dimensional state and the time increment chosen to satisfy the stability conditions. [parmakian(1963) and streeter (1993)] this method above is used in this research and it is discussed briefly in the next paragraph. 1-theory of the research the theory of the research includes the characteristic equations are written to solve the problem and the simple and complex boundary conditions. the characteristic equations may be written as: p q = p c pa hc [4.1] qp = cp + ca hp [4.2] aaaap qtqrh a ga qc ∆−+=∴ [4.3] bbbbn qtqrh a ga qc ∆−−= [4.4] and a ga c a = [4.5] noting that equation [4.1] is valid along the positive characteristic line ap and equation [4.2] is valid along the negative characteristic line bp as shown in figure(1) the values of constants cp and cn are known for each time step and the constant ca depends upon the conduit properties . referring to equation [4.1] and equation [4.2] the values of two unknowns qp and hp can be determined by simultaneous solving of these equations , i.e. ( ) npp ccq += 5.0 [4.6] and by substituting the values of qp at either equation [4.1] or equation [4.2], the value of hp can be determined. however, at the boundaries, either equation [4.1] or equation [4.2] is available. therefore, special boundary conditions to determine the conditions at the boundaries at time (to subscript �t) are needed. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � figure (2) shows a pipeline divided into (n) reaches each having length ( �x ). the ends of these reaches are called sections , nodes or grid points . the end sections of each pipe are referred to as boundaries, and the sections excluding the boundaries are called interior sections, interior nodes or interior grids. 2boundary conditions in the last section, the required special boundary condition have been discussed to determine the transient state head and discharge at the boundaries. these conditions are in terms of special relationships that define, at the boundary, the discharge, the head, or a relationship between them. these boundary conditions may be classified into two categories as, simple and complex boundary conditions. 2.1. simple boundary conditions simple boundary conditions are those which are simple to handle and can take the form of specifying either the head or the discharge as a constant ( as at a dead end of a pipe), specifying relationship between them (as at a valve) or specifying either as a function of time. 2.2. complex boundary conditions complex boundary conditions are usually difficult to handle than simple boundary condition. pump failure, control devices and column separation are examples for this kind of boundary. in alkut water supply project, transients are caused by a disturbance introduction. this disturbance may be caused by opening or closing of a regulating valve that control reservoirs inlet, also sudden stopping of pumps, i.e, power failure. pressure changes during transient state depend upon the rate of change in the initial flow condition. the change in pressure is more dangerous, therefore, the pump starting is made on the condition that the delivery valve is closed, then opened slowly after 90 seconds after the motor starting. the basic characteristics of al kut water supply project are summarized at tables (1) and (2). the results the results of the transient state analysis obtained from the mathematical model may be summarized in tables (3) and (4). al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � conclusions analysis with two air vessels for western, eastern, southern pipelines and one air vessel for northern pipeline is very suitable to keep the transient state pressure within a tolerable limits. the tolerable limits of high and low pressures are between (0 – 100) m. many values of head loss through the vessel outlet were assumed to give the desirable limits for pressure head and minimum number are used of control devices at the same time. results also indicated that the water level at the main reservoir could substantially change the computed minimum pressure. the results showed that when the minimum operation level has been used, the worst case occurs. the properties of the vessel which was selected for the new al – kut project were: 1) diameter = 2.51 m, 2) v11olume = 18 m3, 3) height = 5.86 m, 4) minimum water level = 2.75 m. recommendations several recommendations are given below. it is representing guidance for further improvements and as extension of this study: 1. possibility of optimizing the effects of the air vessels by placing them at different location in the network and thus reduce the number of air vessels required. 2. make a comparison between several kinds of control devices by applying them to a case study and then the results have been discussed and compared. references abd al-abbas, f, "water hammer analysis for najaf-kufa water supply project using characteristics method", m.sc. thesis , university of technology, 2000. al – kut water administration ,”al – kut water supply systems – integration study review – final report” ,2008 chaudhry ,m.h.,”applied hydraulic transients”,2nd edition, van nostrand reinhold company,new york,1987. larreteguy a., carrica p., bali o j. and santa ana p., ‘‘what: water-hammer analysis in tubes", v.1.0 – us journal of hydraulic research, vol. 40, no. 153, 2005. parmakian, j. ,”water hammer analysis”, dover publications ,new york,1963. roberson,j.a.,cassidy,j.j. and chaudhry, m.h., ”hydraulic engineering”, 2nd edition,john wily and sons,new york,1998. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � smith ,g. d., ”numerical solution of partial differential equations” 2 nd edition, clarendon press, oxford, england, 1978. streeter, v.l., "transient in closed conduit systems", colorado state university, 1971. streeter, v.l. and wylie,e.b., ”fluid transients”, prentice hall, new jersey,1993. vardy a.e. and hwang k.l.: ‘‘a characteristics model of transient friction in pipes’’, journal of hydraulic research, vol.29, no.5, pp.669-683, 1991. white f.m.: "viscous fluid flow", second edition, mcgraw-hill, inc.,1991. wylie e.b and streeter v.l.: "fluid transients", corrected edition 1983, feb press, usa. zuhair, r, "water hammer analysis for baiji water pipe line using characteristics method", m.sc. thesis , university of baghdad, 1987. table (1) : characteristics of al-kut water supply project pump name rated discharge (m3 / min) rated head (m) power (kw) rated speed (nr) specific speed (ns) efficiency (%) western p.l 22.02 36 150 1450 1.53 82 eastern p.l 22.32 44 187 1450 1.53 85 southern p.l 22.02 36 150 1450 1.53 82 northern p.l 16.5 33 164 1450 1.53 75 table (2) : diameters and lengths of the pipes of al-kut water supply project pipe name diameter (mm) length (m) western p.l. 900 4500 eastern p.l 900 5000 southern p.l 900 4000 northern p.l 900 1000 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � table (3): minimum and maximum pressure of mathematical model without air vessels. pipe name minimum pressure (m) maximum pressure (m) western -25 118 eastern -20 111 southern -24 124 northern 13 105 table (4): minimum and maximum pressure of mathematical model with air vessels pipe name minimum pressure (m) maximum pressure (m) no. of air vessels western 25 58 2 eastern 12 80 2 southern 25 60 2 northern 36 53 1 figure (1): characteristic lines in x-t plane x t �x = a �t c+ c p b al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 � � figure (2): characteristic grids �x �x �x �x �t �t �t �t �t �t article al-qadisiyah journal for engineering sciences 15 (2022) 208–211 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohammed.abbod@qu.edu.iq (m. abdulrazzaq) https://doi.org/10.30772/qjes.v15i3.840 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. effect of ball milling on niti powder metallurgy alloy noor sami a, m. abdulrazzaq *b and amar albaaj b a department of mechanical engineering, college of engineering, university of al-qadisiyah, iraq b department of materials engineering, college of engineering, university of al-qadisiyah, iraq a r t i c l e i n f o article history: received 08 june 2022 received in revised form 13 august 2022 accepted 15 september 2022 keywords: nickel alloys powders x-ray a b s t r a c t mechanical alloying, especially nickel-titanium alloys, has attracted great interest recently as researchers strive to enhance the properties of nanocomposites, expand their usefulness, and how produce them at minimal costs and produce homogeneous fine powders. in this paper, high-energy ball milling was used to produce ti-ni ultrafine powders. the effects of grinding parameters such as grinding tools and the initial state of powders, grinding conditions such as operating times, in addition to the effect of equal size balls and the speed of the grinding machine, were investigated while avoiding contamination of the powders in contact with air by applying silica. milling process balls such as x-ray diffraction, sem, eds, plus particle size. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the complex nickel-titanium (niti) alloy has attracted the attention of many scientists due to its unique and distinctive properties such as elastic behavior and transition temperatures, in addition to its return to its original form after being deformed by up to 8%. [1,2,3]. the transformation temperatures (tts) and shock resistance, in addition to the fact that they do not wear out easily and are inexpensive, have additional qualitative features that make them a mainstay in achieving the desired development. other beneficial properties of this alloy include biocompatibility and low modulus of elasticity [4,5]. due to the difficulty of creating these alloys by casting method, because their components are immiscible in the liquid state or difficult to melt, powder metallurgy has become popular in recent years [6,7]. net to create complex niti components that allow adaptation of the microstructure and thus important alloy features including valley elastic behavior and transition temperatures [8]. however, the inability to fabricate complex niti parts have limited the application potential, which can be linked to challenges in processing niti due to the strong alloy interaction, as well as martensite-induced stress, work hardening, and modification. as a result, composite materials with specific features and properties are critical [9,10]. the highly flexible niti effect, combined with free-form design and production, creates a particularly attractive combination for engineering applications. through reversible stress-induced conversion, niti can recover a large amount of strain (up to 8% strain) in superplastic [11]. in general, the highly elastic response of niti is highly dependent on the exact structural properties of the alloy. sintering furnaces were produced in larger capacities with greater productivity, and vacuum sintering furnaces were used in some applications. the aviation sector, which includes aircraft, engines, and compressors, as well as the missile, ship, and vehicle engine industries, are the primary applications [12,13]. however, the high cost of manufacturing is a downside to these compounds. in this research, the mechanism of powder manufacturing in a ball mill will study the powder form after the mixing and blending process that takes place, knowing the percentage of change that occurs. http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i3.840 http://creativecommons.org/licenses/by/4.0/ noor sami et al. /al-qadisiyah journal for engineering sciences 15 (2022) 208–211 209 2. experimental setup 2.1 material preparation الترجمة طويلة جًدا وال يمكن حفظها. in this research, nickel-titanium powder was used with nickel powder with 99.5% purity and titanium powder with 99.9% purity as shown in table 1. table 1. powders, purity, and source supplied. 2.2 particle size analysis the ni and ti nanoparticles produced were characterized in a particle size analyzer (better size 2000 instrument, usa). about a gram of each nickel titanium was taken and placed in a glass beaker containing distilled water with a magnet to move the powder in the water. then the powder with water is added to the particle size test analyzer as in fig.1. figure 1. particle size analysis 2.3 x-ray diffraction (xrd analysis) the sintered niti alloy sample as well as the produced niti nanoparticles were examined using an x-ray diffractometer (model: labx xrd-6000, company: shimadzu, us). the functional x-ray tube contained cu (1.54060 a), 40 kv, and 30 a. xrd data were gathered using a step size of 0.2 and an enumeration time of 1.20 seconds over a scan range of 10 to 90. 2.4 energy dispersive spectroscopy (eds) this test is used to find out the components of the mixed powder and the proportion of materials forming the nickel-titanium alloy by placing the power in an energy-dispersive spectroscopy test device and determining the average value of the chemical composition. the elemental structure of each of the niti nanoparticles was examined using eds analysis (company: bruker, germany) table 2. shows the results of the eds test for niti alloy after mixing 2.5 scanning electron microscope (sem) sem is one of the most common surface analysis techniques where a wide range of metrics and features can be observed. in the present work, sem is used to identify the alloy components and the proportion of nickel and titanium produced by the powder metallurgy process. the test was carried out in the materials lab of al-razi metallurgical research centre, tehran/iran. micrographs are taken with a magnification of 5.00kx as shown in fig. 2. figure 2. scanning electron microscope device 2.6 ball milling spherical mills (n q m 0 4, made in china) were used. the mixing and homogenizing process takes place in different ways, but in ball mills, mixing and grinding take place at the same time as shown in fig.3. figure 3. the mixing mechanism in ball mills initially, nickel powder and titanium powder were weighed in equal quantities utilizing a sensitive scale, with an accuracy of 0.001, and the two materials were placed together in the mixing pouches of the ball mill with nine balls (weighing 14 g, and a diameter of 16 mm made of stainless steel). these balls are used for grinding powder more and more to get a fine powder. the process of mixing nickel and titanium powder was completed materials purity% average particle size(µm) source titanium powder 99.75% 12.06 galaxy international trade co., ltd. nickel powder 99.65% 36.80 210 noor sami et al. /al-qadisiyah journal for engineering sciences 15 (2022) 208–211 for ten hours, and the speed of the mixing process was 35r.p.m, which is the maximum speed of the planetary ball mill. fixed pauses were done at room temperature to control the porosity and bring it to the right amount. 3. results and discussions ا. through the experiments the particle size reduction, newly formed surface area, the changes in xrd diffraction pattern, and broadening of the diffraction lines and microstructural characters were measured and estimated. some important features of the obtained results are given in the following sections. 3.1 x-ray diffraction (xrd analysis) the logarithmic graphic shows the niti particle size range (20–5000 nm) in terms of diameter. the chemical processes that occur between niti and the solution are mostly what determines how ti and its alloys are treated. five peaks can be observed at 5.38 = 2ȣ, 9.44, 65, 78, and 5.82 degrees. the observed ni peaks are very close to the reference value of 40.0 nm. compared to the starting powder style, the mills show an expanded density which means the powder size is effectively reduced after the grinding process. figure 4. x-ray test the granular particles represent the ni3ti phase, whereas the matrix represents the niti phase. the xrd patterns of niti particles are displayed. the ni3ti phase is indicated by the greatest peak in the xrd pattern, and there are also high peaks for the phases between niti and tio2. ti is more reactive than ni, so when it comes in touch with oxygen, tio2 begins to develop on the powder right away. since the free enthalpy of production of tio2 is negative and greater than that of nickel oxides, it consists primarily of tio2. tio2 creates a physical and mechanical barrier to nickel oxidation and shields the alloy from corrosion. on the other hand, the niti nanoparticles' xrd pattern, fig. 5. figure 5. xrd pattern of niti particles the main metallic phases are niti, ni3ti, and ti2ni, which are the stable phases of niti alloy. the particle size results are illustrated in fig.3. particle size analysis (ti) particle size analysis (ni) figure 6. particle size analysis diagram of ni and ti nanoparticles 3.2 scanning electron microscope (sem) and energy dispersive spectroscopy (eds) the outcome of niti nanoparticles is depicted in fig. 6, based on sem and optical micrographs and the objective of eds investigation. since ti is more acid resistant than ni, the observed variation in the elemental composition ratio of niti particles can be attributed to this differential in the acid resistance of each element. additionally, compared to the ti particles, the ni particles used were smaller, table 1. table 3 shows the chemical composition of the blended powder alloy. in this study, it was prepared in equal weight ratios to contain 50 wt% ni + 50 wt% ti, which corresponds to 49.9 wt% ni and 50.04 wt% ti. according to eds results, ni and ti are the only elements present. these findings may be explained by the eds analysis's characteristic of just analyzing the area where the electron struck. the findings of the eds study were, as can be seen, rather near the required percentage. 3.3 the ball milling a little amount of powder is trapped between two colliding grinding balls. it typically held during this process, each impact produced around 1,000 particles with a combined weight of about 2.0 mg, allowing for adjustment of the powder's morphology. when dealing with tiny powders like nickel and titanium, overlapping cold welds are created by the flat layers. as a result, layered composite powder particles are created. it is made up of many starting set compositions. it is possible for components that work to harden or composite powder particles to fail at the same time. these opposing actions—cold welding (plastic deformation and agglomeration) and crushing (size reduction)—occurred repeatedly during the milling operation. finally, a finely tuned and homogenous microstructure is noor sami et al. /al-qadisiyah journal for engineering sciences 15 (2022) 208–211 211 achievable, and the powder particle composition is identical to that of the initial powder ratio. figure 7. sem micrograph of nickel-titanium powder milled for 10 h 4. conclusion the results presented in this paper show that the techniques developed and used in this study are well suited to optimizing the grinding parameters of a nickel-titanium alloy to investigate the effect of grinding parameters on the structure and properties of ground materials as well as on the grinding energy values. revolutions per minute with a pause time and the powder remains in the grinding bowl of the ball mill for 24 hours after every 4 hours of operation time. the change in the powder composition was observed after the series of grinding and suspension, which generates high heat that leads to the cohesion of the powder, and then cracking this cohesion when the powder is confined between two balls, thus changing the shape, size and chemical composition of the powder, and this is what was observed in the test that we carried out in this research. references [1] e. o. nasakina, m. a. sevostyanov, a. s. baikin, a. v. seryogin, s. v. konushkin, k. v. sergienko, a. v. leonov and a. g. kolmakov, applications of nanostructural niti alloys for medical devices, (2017). [2] p. majeric, r. rudolf, i. anzel, b. friedrich, j. bogovic, and s. stopic, nanoparticles prepared from niti orthodontic wire, (2015). [3] m. speirs, x. wang, s.v. baelen, a. ahadi, s. dadbakhsh, j.-p. kruth, j. v. humbeeck, on the transformation behavior of niti shape-memory alloy produced by slm, (2016). [4] d. mutter and p. nielaba, simulation of the thermally induced austenitic phase transition in niti nanoparticles: simulation of phase transitions in niti nanoparticles,(2011). [5] d. d. radev, mechanical synthesis of nanostructured titanium–nickel alloys,(2010). [6] h. b. liu, g. canizal, p. s. schabes-retchkiman, and j. a. ascencio, structural selection and amorphization of small niti bimetallic clusters, j. phys. chem., (2006). [7] a. r. jaber, e. s. al-hassani, a. m. al-shammari, m. a. najim, a. a. hassan, and a. a. ahmed, evaluation of stem cells’ growth on electrospun polycaprolactone (pcl) scaffolds used for soft tissue applications, (2017). 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[14] b. li, l. rong, and y. li, microstructure and superelasticity of porous niti alloy, sci. china, ser. e technol. sci., 42, 1, (2009). article al-qadisiyah journal for engineering sciences 15 (2022) 127–131 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: kmesser@okstate.edu (kyle messer) https://doi.org/10.30772/qjes.v15i2.823 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. the experimental methods and elastic properties of shale bedding planes materials state-of-the-art review kyle r. messer a*, ali fahad fahem a,c, achyuth t. guthaib, and raman p. singha,b a school of materials science and engineering, oklahoma state university, tulsa, ok, usa b school of mechanical and aerospace engineering, oklahoma state university, tulsa, ok, usa c department of mechanical engineering, collage of engineering, university of al-qadisiyah, al-diwaniyah, iraq. a r t i c l e i n f o article history: received 26 may 2022 received in revised form 28 june 2022 accepted 20 july 2022 keywords: shale damage fracture properties review a b s t r a c t the identification of physical properties and fracture behavior of shale or hydrocarbon materials has grown to have substantial importance in the last four decades to industry and investigators alike due to its importance in unconventional oil and gas resources. this interest deviates from shale being a transversely isotropic material formed by bedding layers with different orientations and isotropic properties. in this paper, the experimental setup and the mechanical properties of shale materials have been reviewed. the investigator shows that the properties of shale are not unique, and it is highly dependent on, volume, loading type, and geolocation. furthermore, the investigator utilized different experimental setup methods to identify the elastic properties of shale and the most common methods are transducers strain detection, strain gauges, ultrasonic, and digital image correlation that is shown in detail. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction the investigating and testing of the mechanical properties of shale materials are an interesting topic for the last four decades by researchers. the most interest has been in regions rich with organic shales like the midwest of america, canada, australia, china, russia, and a few countries in europe. oil and gas extraction enhancement is the primary goal from a mechanical engineering standpoint. the enhancement of shale and porous rock will increase the injection and storage of co2 into the ground, one of the safest technologies currently used. however, a full understanding and information on transversely-isotropic material, as shown in fig.1, and to understand its mechanical properties and fracture behavior, different experimental and numerical simulation setups were used. the utilization of fracture mechanics to determine mechanical properties, which is the scope of this article, applies linear elastic fracture theory as a base for analytical solutions and is a common technique for many investigators. fig.2 is an sem image showing the sedimentary rock containing at least 30% of clay which is known as shale, and its properties are dependent on microstructural http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i2.823 http://creativecommons.org/licenses/by/4.0/ 128 kyle messer et al. /al-qadisiyah journal for engineering sciences 15 (2022) 127–131 features, intra-granular porosity, anisotropy degree, petrophysical characteristic, mineralogy, thermal history, organic content, location, depth, and so on. of the porous rock and shale are needed [1]. in general, there are no unique parameters for shale. experimentally, different setups were used to understand shale behavior such as large-scale simulation, acoustic wave operating, stress wave propagation, digital image correlation, and three-point bending experimental apparatuses. most of these experimental setups are carried out on two bedding orientations relative to the loading direction, longitudinal, and transverse directions. however, the result shows different shale responses and properties, as shown in table 1. in table 1, for example, gautam tests the shale using transducer strain detection and transverse isotropy. the result is dependent on the global data and shows that the elastic modulus is the same in compressive and tension, and the inelastic modulus in the longitudinal direction is larger than the elastic modulus in the transverse direction. in addition, ye used line data information from the tsd, sg, dic, and bm. he found that the elastic modulus with a longitudinal direction under tensile load is smaller than the elastic modulus along the transverse direction under compressive load. for the same materials, there are different results as shown in table 1. table 1 shows that the shale is transverse-isotropy is the isotropic material response in one plane and different in the other plane, while bi-modulus materials refer to the elastic modulus in tension being different from compression. furthermore, shale has distributed micro or macro cracks at different locations and orientations, as shown in fig.2. in this work, the experimental method of shale materials is covered, then fracture mechanics data is listed following the summary and the general notes. [2] table 1. transverse-isotropy shale response and the experimental method author tsd sg us dic bm ti data result gautam [3] global 𝐸𝑙𝑙 𝑡 > 𝐸𝑡𝑡 𝑡 hakala [4] global 𝐸𝑙𝑙 𝑡 > 𝐸𝑡𝑡 𝑡 wong [5] global 𝐸𝑢𝑙, 𝐸𝑠𝑡 ye [6] line 𝐸𝑙𝑙 𝑡 < 𝐸𝑡𝑡 𝑐 ming [7] point 𝐸𝑙𝑙 𝑡 > 𝐸𝑡𝑡 𝑡 shant. [8] line 𝐸𝑙𝑙 𝑐 > 𝐸𝑡𝑡 𝑡 segam. [9] local 𝐸𝑙𝑙 𝑐 > 𝐸𝑡𝑡 𝑡 where: mean the author used this method, and mean not. tsd: transducers strain detection sg: strain gauges us: ultrasonic dic: digital image correlation bm: bi-modulus ti: transverse isotropy 2. the experimental methods as shown in fig. 3, there are many examples of experimental setups that are used to investigate the physical properties (mechanical properties) of shale. the standard specimen geometry for shale and rock is circular or cylindrical, and the load is an indirect tensile test or direct compressive test. however, the method to measure the deformation and strain will vary based on the chosen method, as described in the following references [5], [10], [7], and [8]. luo et al., 2018, studied anisotropic shale bedding planes. the research aims to understand the crack extension, the effect on the bedding planes, and the effects of anisotropy of shale regarding fracture toughness and crack extension characteristics. the authors mentioned that the crack behavior and fracture on the shale could alter based on pressure change brought from the sem and did not discuss the effect of hydraulic liquid on the fracture properties. this hydraulic liquid would create a realistic simulation of shale fracture in field situations. in addition, only the theoretical stress field was investigated, and mode-ii fracture was claimed to be negligible on account of the stress concentration factor. [11]. chalivendra et al., 2009, studied predictive simulations for dynamic fracture along weakened planes that were challenging and lacked fitting parameters for accurate results. the group aimed to compare predictive data generated from experiments with published data and numerical simulations. they used a modified hopkinson bar setup with photoelastic experiments on a notched face specimen to obtain controlled loading fracture crack propagation. an inverse problem of cohesive zone modeling is used to obtain mode-i cohesive zone laws. the authors found that both the experiments and the numerical simulations result in comparable crack figure 1: example of shale core [2] figure 2. typical of microstructure of sedimentary rock (shale) kyle messer et al. /al-qadisiyah journal for engineering sciences 15 (2022) 127–131 129 initiation times and create similar crack tip velocities with a difference of less than 6%. the results confirm that the detailed shape of the non-linear cohesive zone law does not have a significant influence on the numerical results [12]. [13] tan, 2018, studied the bedding influences on coal mechanical behavior in underground environments such as coal or rock bursts. the author conducted this research using eight specimens and numerical models of dynamic shpb using micro parameters of pre-stressed coal with different bedding angles to study the effects of bedding angles on failure patterns. three impact velocities of 4, 8, and 12 m/s were used to study the dynamic of coal-containing bedding planes under different loads. the results showed that the existence of bedding planes leads to the degradation of the mechanical properties, and their weakened effect significantly depends on the bedding angle between the bedding planes and load direction. the bedding angle was changed from zero to ninety degrees in 15-degree increments. the result shows that the strength first decreased and later increased as the angle increased. the specimen became most vulnerable when the bedding angle was thirty or forty-five degrees. also, energy characteristics combined with ultimate failure patterns showed that the maximum accumulated energy and failure intensity has a positive relationship with the strength of the specimen. when bedding planes were parallel or perpendicular to the loading direction, specimens absorbed more energy and expensed more aggressive failure with an increased number of cracks. however, bedding planes with 30 or 45 degrees reduced the specimen's ability to store strain energy to the lowest, with fewer cracks observed after failure. the numerical and experimental results show a 26.73% error in the failure strain. however, the other mechanical properties were accurate jian et al., 2020, focused on studying the effects of bedding structures on the acoustic characteristics of shales at operating frequencies of acoustic logging, and an acoustic transmission apparatus is used to determine acoustic wave propagation characteristics in shale with various bedding angles. a numerical model based on the viscoelastic properties of shale is used to estimate the density, the effects of the angle, and thickness of bedding planes on the acoustic characteristics of shale at operating frequencies of acoustic logging. it was shown that the bending angle is the primary feature when observing the shale bedding structure and significantly affects acoustic wave propagation. the wave velocity and main amplitude increased with increasing bedding angle. the wave velocity decreased with an increase in the bedding density and thickness when the acoustic waves were transmitted through the shale numerical model. significant reflection and refraction of the acoustic waves propagate through shale resulting in energy loss[14]. daehnke, 1999, used experimental and theoretical approaches to develop a full simulation model to understand the behavior of rocks sufficiently. this work is essential to underground and open-cast mining operations. three dimensional, pmma, cube-type laboratory experiments are loaded with explosives and dynamically tested. photoelastic and high-speed imaging techniques are used to examine fracture evolution [15]. the interaction between stress waves and a crack was reviewed by williams, 2009 [16]. the publishers mention that it is crucial to understand the dynamic fracture of engineering materials and its initiation and propagation of cracks subjected to elastic, plastic, or shock waves. elastic stress waves theory of elastodynamics is utilized to better understand the dynamic fracture of engineering materials as the initiation and propagation of cracks that are subjected to elastic, plastic, or shock waves. multiple topics are reviewed and related to the elastic stress wave. this paper contained multiple experimental methods that used a disc for loading a halfplane crack with a tensile pulse. the response of a crack under plane strain loading using a plate-impact setup. also, the effects of dilatational (longitudinal) and transverse (shear) waves interacting with a crack were analyzed. they did not mention the effects of weakened planes between the stress waves and cracks. meier et al, 2015, [17] point out that 75% of wells are drilled from sedimentary basins worldwide in the research. however, there are instability issues from borehole drilling that are not entirely understood. the stability of wells drilled into bedded formations. for example, shale depends on the orientation between the bedding and the borehole axis. the risk of borehole instabilities increases significantly if the borehole is drilled sub-parallel to bedding. thick-walled hollow cylinder experiments with varying orientations of bedding planes are used to examine the formation of stress-induced borehole breakouts in posidonia shale. the specimens were loaded isostatically until the formation of breakouts. the onset of borehole breakout development was determined through acoustic emission activity, strain measurements, ultrasonic velocities, and amplitudes. as the bedding plane inclination angle changed from perpendicular to parallel to the borehole axis, the critical pressure for breakout initiation decreased from 151 mpa by approximately 65 %. shale bedding structure showed an anisotropy in elasticity and strength that resulted in a change in the strength that dominated the integrity of the thickwalled hollow cylinders. the initial failure was the result of slip along bedding planes. the initial failure was a starting point for more severe breakouts forming either as shear or buckling failure. kramarov et al., 2020, found that hydraulic fracturing is dependent on the height and width of the figure 3. examples of experimental setups that are used to investigate the mechanical properties and fracture toughness of shale: a) wong setup [5], b) hakala setup [10], c) brazilian disk, d) ming setup [7], shantonu setup [8] 130 kyle messer et al. /al-qadisiyah journal for engineering sciences 15 (2022) 127–131 fracture and the major component of controlling the fracture size is the use of the formation fracture toughness[18]. berea sandstone and manco's semi-circular bend test (scb) and digital image correlation (dic) are utilized at varying notch orientations concerning the bedding planes. fullfield displacements determine the fracture process zone and williams' series solution to extract critical stress intensity factors. essential parameters for measuring fracture toughness using dic displacements depend on the area of interest (aoi), the field of view (fov), and the number of terms of solution (n). values for fpz and fracture toughness are reported and show to be in good standing. aliha et al., 2012, studied shale fracture under indirect tensile load to better understand mixed-mode fracture toughness on brittle materials such as marble. the fracture toughness describes the resistance of rock materials against crack propagation. two separate mixed-mode fracture experiments were utilized on harsin marble. one was the brazilian disc, and the other was the semicircular bend specimens, and a range of pure mode-i to pure mode-ii fracture toughness a fracture envelope was developed. the results show that the major takeaway from these experiments is that fracture toughness depends on geometry and loading. generalized equations which account for geometry and loading are the best ways to fracture toughness. this is proven with the experimental results of the bd and scb experiments [19]. 3. the outline fracture data there are considerably more numerical and theoretical studies than there are laboratory experiments for crack tip interactions within the load. the investigator found that the most common discussions included • however, there is a disparity in results. the primary cause for this is the bedding planes' thickness, voids, and the geological characteristics of shale. fracture toughness yields the best results when a generalized equation considering loading and geometry is utilized. most researchers include a discussion about fracture process zone (fpz). the results exhibited brittle fracture in the shale, and the fracture strength was strongly dependent on the bedding plane inclination angle. • crack propagation initiated along the bedding plane when the bedding plane inclination angle was high such as angles greater than 60 degrees. however, angles at and below 30 degrees showed that cracks penetrated the matrix. higher fraction toughness was reported with a lower bedding plane inclination angle. • the stress field around the crack tip was analyzed theoretically and an equation was derived. a criterion for determining whether a crack extends along the bedding plane was developed by differentiating the characters in the strengths of the shale bedding and the matrix. • the crack tip stress field is determined by the three major factors: the stress intensity factor and the elastic constants, and the bedding plane inclination angle. • most of the work discusses mode-i of fracture and does not discuss the effects of angles for mode-i and mode-ii fracture and process zone on the rock specimens [20]. • the fracture process zone was not mentioned throughout in rock specimen studies. the discussion was based on a global scale and not regarding fracture toughness. • the ctod and the development of the cohesive zone model are not discussed in detail in most works. however, most discuss the importance of the fracture process zone regarding sandstone and shale. the fracture process zone is a vital characteristic of brittle material because it characterizes its liability of fracture toughness. the brazilian disc and semi-circular bend specimens harsin marble specimens are common specimens’ geometries to determine the mixed-mode fracture toughness and fracture envelope. however, most were interested in isotropic material and did not look at the shale's weakened planes. • the shale can be tested under torsional stress wave using the spiral crack and investigate the mixed mode fracture under low and high loading rates, [21-22] 4. summary numerous experimental techniques have been used to investigate the fracture mechanics of shale using global or far-field load and deformation data or local and deformation data. the most common are transducers strain detection, strain gauges, ultrasonic, and digital image correlation. unfortunately, in all these methods the weak plane behavior and effect on the fracture have not been considered. however, the shale fractured and fragmented in three dimensions depending on the direction of the weak plane. some researchers focus on the weak plane but use numerical simulation with no experimental test. in a dynamic case, the numerical model of an shpb is utilized to investigate micro parameters of pre-stressed rock specimens with different bedding angles to study the effects of bedding angles on failure patterns such as the elastic strain energy. the acoustic logging that characterizes shale's bedding structure at various angles was also used but is not related to the weak plane. up to today, there are a few points that need to be covered by the researcher in detail as follows: • use the cohesive zone laws along the weakened planes. extend acoustic wave interactions between the bedding planes and characterize the strength of the bedding planes and the fracture. • there have been reviews such as williams's a concise review on the interactions between stress waves and cracks. however, this review does not consider the effect on weakened planes and stress waves along the weakened, cracked body. • . there is a large potential for the exploration of energy dissipation regarding bedding planes. • crack-load interactions along weakened planes have the potential for development. • stress wave interactions are mainly explored using photoelastic techniques and have not been looked at with modern and developing techniques such as dic. acknowledgment this material is based upon work supported by the department of energy under award number defe0031777. this report was prepared as an account of work sponsored by an agency of the united states government. neither the united states government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed or represents that its use would not infringe privately owned rights. reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the united states kyle messer et al. /al-qadisiyah journal for engineering sciences 15 (2022) 127–131 131 government or any agency thereof. the views and opinions of the authors expressed herein do not necessarily state or reflect those of the united states government or any agency thereof. references [1] 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[19] m. r. m. aliha, m. r. ayatollahi, and j. akbardoost, “typical upper bound lower bound mixed-mode fracture resistance envelopes for rock material,” rock mech. rock eng., vol. 45, no. 1, pp. 65–74, 2012, doi: 10.1007/s00603-011-01670. [20] fahem, a., kidane, a. & sutton, m. loading rate effects for flaws undergoing mixed-mode i/iii fracture. exp mech 61, 1291–1307 (2021). https://doi.org/10.1007/s11340-021-00739-0 [21] ali fahem, addis kidane, michael a. sutton, mode-i dynamic fracture initiation toughness using torsion load, engineering fracture mechanics, v 213, 2019, 5371, https://doi.org/10.1016/j.engfracmech.2019.03.039. [22] fahem, a.f., kidane, a. & sutton, m.a. a novel method to determine the mixed mode (i/iii) dynamic fracture initiation toughness of materials. int j fract 224, 47–65 (2020). https://doi.org/10.1007/s10704-020-00445-3 https://www.claysandminerals.com/materials/shales http://oai.dtic.mil/oai/oai?verb=getrecord&metadataprefix=html&identifier=ada499445 http://oai.dtic.mil/oai/oai?verb=getrecord&metadataprefix=html&identifier=ada499445 https://doi.org/10.1007/s11340-021-00739-0 https://doi.org/10.1016/j.engfracmech.2019.03.039 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� two–input epicyclic–type transmission trains with application to tandem bicycling essam lauibi esmail shaker sakran hassan technical institute of diwaniya, associated professor of mechanical engineering diwaniya, iraq university of technology, baghdad, iraq abstract this paper presents a unification of kinematic and torque balance methods for the analysis of twoinput epicyclic-type transmission trains. a method for the derivation of the velocity ratio of an epicyclic gear train in a symbolic form is developed. a single kinematic equation is derived to study the kinematic characteristics of fundamental gear entities. the method relies on previous work on graph theory. it improves on existing techniques used for automatic transmission mechanisms in its ability to accurately solve the kinematics of geared mechanisms and estimating their velocity ratios and arranging them in a descending order in a simpler manner. the results are then used for assignment of the various links of a given two-input epicyclic gear mechanism. this study contributes to the development of a systematic methodology for the torque and power flow analyses of two-input epicyclic gear mechanisms with a reaction link, based upon the concept of fundamental circuit. specifically, this study presents for the first time a complete design and analysis of two-input velocity changer to be used as a power coupling in a new generation of tandem bicycles. two new designs are demonstrated. keywords: epicyclic gear train, kinematics, power-flow, tandem bicycle, transmission, two-input, velocity ratio. �*� ���=�, )�� >�! ��? >��,�,�? �"���� ��&�� �����"�!�� ��� ��� 34 ��&����� �� ���,� �� >$�"�� .��� � ��� ��b 5�c� #"���� �.� � q��(�(�< q�!���< ��������� ��(���� �(� 59$�� �9���� ��� �� d . q'c��� [���2< 5� q�>� ���!�� n! �� d�c�@�q ���' � � q'�(���� �(�� ���!�� !���� m� �� q�(���� �( q���$� d�c�@� 5� �� q��(�(�< �3! !� � q�!�!�� q�!���< q�.� ��� . � qc����< ���$�� ���'����� ��'� c��� ��! � �> 5b�!� �� ����"��� ��l �> d��! #�� � ���!�� ���! ���"�� q�!���< ����h� ��(���� �(� d�2��� # �� � � �����2 �> ��h� (� �� #c ����\ !��� �> q��"�!����q ���9� � �������� " ��!� qc���� . %�l� ��� � ��a q 4 �!��� p.�� �� i��� '�.� � q'��(�( q�'!�� q'��^ % �"��� �34�� #"����. m�b 5b�!� !� ���� d>��� 5�9$�� #� �� q��� � qc��� ����� �> qm��c�< #c ����\ #3" (� �� q�!���< q'��(�(�< �����!. 3����� +�$� @ �� >�������? 3�*��� ������ �!) �� ,! ,�0 ���!� ���!? �������,��� >�����? al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 5��%� � � �������� 6q������< �34 � � y�� � ����� #"���� �.� ���.���� q�!�!�� . 'b 5�c� =�" #(@�� '!����� m�q ����4� "3� �� " '�.����� �������� �� ���� #�� �> m��c�< �� ��� ��2 �> q���"�!� #"���� �.� � ���! #���� �� ��( n(���� �.� � .�� �� qc����< [����� "3�4%� �� ���� 5� �c> "������ �����4� �> . nomenclature egm epicyclic gear mechanism egt epicyclic gear train fc k th k fundamental circuit fge fundamental gear entity xp n , gear ratio defined by a planet gear p with respect to a sun or ring gear x. xpxp zzn / , ±= , where pz and xz denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative signs depends on whether x is a ring or sun gear. r z yx , or e velocity ratio between links x and y with reference to link z t kga , , t kgb , and t kc , or ti external torques exerted on links ga, gb and c of the th k fundamental circuit or exerted on link i two-dof two-degree of freedom zi number of teeth on gear i c carrier ga gear a gb gear b p planet gear r ring gear s sun gear i ω angular velocity of link i introduction a literature survey reveals that numerous methodologies have been proposed for the kinematic analysis of epicyclic gear trains [1, 9, 14, 15, 18 and 23]. using graph theory, (buchsbaum and freudenstein, 1970) investigated the structural characteristics associated with epicyclic gear trains (egts) and proposed a systematic methodology for the structural synthesis of such mechanisms. subsequently, (freudenstein, 1971) proposed a systematic methodology for the kinematic analysis of egts. freudenstein's method utilizes the concept of fundamental circuits which can be readily derived from the graph of an egt. the method was elaborated in more detail by (freudenstein and yang, 1972). conventionally, the analysis is performed manually. recently, there has been an increasing interest in the development of computer aided analysis programs [4, 16]. the concept of fundamental circuit was further extended to force and power flow analysis for egts by other researchers [19, 20 and 22]. (hsieh and tsai, 1996b) apply similar formulations in conjunction with their kinematic study (1996a) to determine the most efficiency kinematic configuration of one-degree of freedom automatic transmission mechanisms (hsieh and tsai, 1998). the concept of fundamental circuit is a powerful tool for automated analysis of egts. however, the analysis involves the solution of a set of linear equations for all the kinematic variables. the area that attracted little attention is the two-dof egts. (corey, 2003) attempted to present a solution technique for finding a total speed and force solution to two-dof egts in the most general case possible. unfortunately, he got confused between the rotational speeds and torques of egts in the general case al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� and those of specific cases, which render those solution techniques physically meaningless (esmail, 2007). (mir-nasiri and hussaini, 2005) had presented a new concept of mobile robot speed control by using two degree of freedom gear transmission made up of a basic egt. a basic egt consists of a sun gear, a ring gear, and a carrier as shown in figure 1. the first step in the design process of two-input mechanisms involves finding the configuration that not only provides the correct speed ratios, but also meets other dynamic and kinematic requirements. in general, in order to create a physical model of the system, all relevant physical relations such as speed, torque and power flow must be examined. the absence of torque and power flow analyses have led to flawed simulation results in (mir-nasiri and hussaini, 2005). the present paper applies the concepts of fundamental circuits and fundamental gear entities (fges) for the kinematic and dynamic analyses of two-input egts. a single kinematic equation is derived to study the kinematic characteristics of fges. the results are then used for the estimation and comparison of various velocity ratios of an epicyclic gear mechanism , which lead to the development of a more efficient methodology for the assignment of the various links of a given twoinput epicyclic gear mechanism. specifically, this study presents for the first time a complete design of two-input velocity changer to be used as a power coupling in a new generation of tandem bicycles. in what follows, the concepts of fundamental circuit and fundamental gear entity will be reviewed. fundamental circuit the fundamental circuit is defined as a circuit consisting of one geared edge and several turning pair edges connecting the endpoints of the geared edges (buchsbaum and freudenstein, 1970). figure 2 (a) shows a gear pair which consists of two gears, ga and gb, and a supporting carrier, c. figure 2 (b) shows the corresponding schematic representation, which is a fundamental circuit. this schematic diagram consists of a block, three nodes, and three chords. the block represents a fundamental circuit. the symbol fc k denotes the th k fundamental circuit of an egt. the nodes represent the links of the fundamental circuit which transfer power or torque to the other fundamental circuits. the chords connecting the nodes to the block are labeled with t kga , , t kgb , and t kc , which denote the external torques exerted on links ga, gb, and c. fundamental gear entity (chatterjee and tsai, 1995) defined the fundamental geared entity (fge) as a mechanism represented by a graph formed by a single second-level vertex or a chain of heavy-edge connected second-level vertices together with all the lower vertices connecting them to the root. figure 1 shows the canonical graph of the basic epicyclic gear train shown in the same figure. there are two frequently used fges, one contains only one planet and the other contains two meshing planets. the graphs and functional schematics of a single-planet fge and a double-planet fge are shown in figures. 3 and 4, respectively. fges with more than two meshing planets and/or with multiple compound planets are not practical (gott, 1991) and will be excluded from this study. in a single-planet fge, the coaxial links include a carrier and several first-level gears meshing with one planet gear. in a double-planet fge, there are two meshing planets, one carrier, and several coaxial gears meshing with either one of the two planets. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� kinematics of fges the velocity relationship among these coaxial links should be established in order to effectively compute the velocity ratios of a transmission mechanism. the term "gear ratio" is used in this paper to denote the ratio of a meshing gear pair, while the term "velocity ratio" is used to denote the velocity ratio between the input link and the output link of an egm. xpxp zzn / , ±= (1) considering the kinematics of a fundamental circuit, the fundamental circuit equation can be written as (buchsbaum and freudenstein, 1970): n xpcpcx ,)()( =−− ωωωω (2) equation (2) can be re-written for the coaxial links of the single-planet fge and the double-planet fge shown in figs. 3 and 4 as follows n ipcpci ,)()( =−− ωωωω (3) n jpcpcj ,)()( =−− ωωωω (4) n kpcpck ,)()( =−− ωωωω (5) and n lpcpcl ,)()( =−− ωωωω (6) dividing eq. (3) by (4) yields a kinematic equation relating the angular velocities of the two gears i and j, and the carrier c. let the symbol r c ji , denote the velocity ratio between links i and j with reference to link c. that is jp ip cj cic ji n n r , , , = − − = ωω ωω (7) the gear ratio for the coaxial gears that are not meshing directly with the planet gear on which the velocity ratio is calculated and are meshing with the other planet gear can be found in terms of the gear ratio of the two planets )( 1, ppn as xpppxp nnn ,11,, .= (8) dividing eq. (3) by (5) yields nnr kpip ck cic ki ,,, = − − = ωω ωω (9) where; kpppkp nnn ,11,, .= , for the double-planet fge. eliminating pω and cω from the fundamental circuit equations (3), (4) and (5), yields al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� kpjp kpip kj kik ji nn nn r ,, ,, , − − = − − = ωω ωω (10) similarly, eliminating pω and cω from the fundamental circuit equations (3), (5) and (6), yields lpkp lpip lk lil ki nn nn r ,, ,, , − − = − − = ωω ωω (11) where; lppplp nnn ,11,, .= , for the double-planet fge. in general we can write zpyp zpxp zy zxz yx nn nn r ,, ,, , − − = − − = ωω ωω (12) using the facts that 1 , = pp n and 0 , = cp n , equation (12) provides a basis for the velocity ratio analysis of single-planet and double-planet fges and so on. only this equation can be used to study the kinematic characteristics of all of the fges, which makes the kinematic analysis of egts very simple. velocity ratio ranges kinematic inversion is defined as the process of selecting the input, output, and fixed links for a mechanism. given three coaxial links x, y and z the following basic characteristics relate the velocity ratios of these links. 1. z yx z xy rr ,, 1= 2. 1,, =+ z yx y zx rr all other velocity ratios of the three links due to kinematic inversions can be found by applying characteristics 1 and 2 as shown in table 1. the velocity ratio ranges are classified into three kinds; greater than one, between zero and one, or less than zero. again, by applying the kinematic inversions, the velocity ratio ranges of an egt can be deduced as shown in table 1. velocity ratio relations a one-degree of freedom egt giving and taking power from the external environment requires at least an input, an output and a fixed link. thus, to function effectively it requires at least three ports. similarly, a two-dof egt requires at least four ports, and so on. following a similar procedure to that used by (hsieh and tsai, 1996b) with major differences, we can write; let r y ox , and r z oy , denote two velocity ratios of an egt. dividing r z ox ,1 − by r z oy ,1 − and after simplification, yields al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� y oxz oy z ox r r r , , , 1 1 1 −= − − (13) dividing r z ox , by r z oy , and after simplification, yields z yxz oy z ox r r r , , , = (14) hence if the ranges of r y ox , and r z oy , are known, the velocity ratio relation between r z ox , and r z oy , can be deduced from eqs. (13) and (14). for example, if 01 , >> r y ox then 0 1 1 1 , , > − − > z oy z ox r r (15) furthermore, if r z oy ,0 > then eq. (15) can be further simplified to 011 ,, >−>− z ox z oy rr . this equation implies that the velocity ratio r z ox , can assume two possible ratio ranges, r z ox ,0 > , and 01 , >> r z ox . from eq. (14), if r z ox ,0 > , then 01 , >> r z yx , and the velocity ratio relations can be deduced as z oy z ox rr ,,0 >> . also, if 01 , >> r z ox , then r z yx ,0 > and the velocity ratio relations is z oy z ox rr ,, 01 >>> . twelve velocity ratio relations can be derived from equations (13) and (14) for any four coaxial links of an egt as shown in table 2. these velocity ratio relations are three more than the nine relations given in (hsieh and tsai, 1996b). this is because that paper has not taken in consideration the effect of r z yx , on the velocity ratio relations. procedure for assignment of four coaxial links of a two-dof egt most enumeration procedures are done through the process of generating and testing. the procedure is thus divided into two parts: a generator of all possible solutions and a tester that selects only those solutions that meet the constraints. an egt can provide several velocities depending on the assignment of the input, output and fixed links. these various velocities need to be estimated and arranged in a descending order to arrive at a proper design. selecting three out of any four coaxial links of an egt (x, y, z, o) at a time, yields four sets of three coaxial links (x, y, z),(x, y, o),(x, z, o) and (y, z, o). by expressing the train velocity ratios in terms of the gear ratios of its gear pairs with the help of eq. (12), the velocity ratio ranges can be estimated without knowing the exact dimensions of the epicyclic gear mechanism. other velocity ratio ranges due to kinematic inversions can be found using table 1. furthermore, the velocity ratio ranges are compared with the velocity ratio relations shown in table 2, to identify all other velocity ratio ranges of the egt. the results are then used to identify the proper assignment of the links of a two-input epicyclic gear mechanism. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� torque analysis torque analysis of a fundamental circuit for a fundamental circuit of an egt, it is well known that under static equilibrium, torques acting on the three links of a fundamental circuit must be summed up to zero: 0,,, =++ ttt kckgbkga (16) it is also well known that under constant-velocity operation and in the absence of friction, the net power passing through a fundamental circuit is zero. power is the product of torque and angular velocity (t.ω): 0... ,,, =++ ωωω ckcgbkgbgakga ttt (17) solving equations (2), (16) and (17), yields: 0. ,,, =+ tnt kgagagbkgb (18) and 0.)1( ,,, =−+ tnt kgagagbkc (19) equations (18) and (19) express two of the external torques in terms of the third. the word "external" refers to all sources that are external to the gear pair of interest. thus, external torques come from all the links that are connected to links ga, gb and c. torque analysis of two-input egts with a reaction link due to the fact that the function of a transmission mechanism is to provide proper torques and velocities for a vehicle, it is essential to identify the relations among the velocity ratio, torque distribution and the power flow in an egm. under steady-state operation, it is well-known that torques exerted on links x, y, z, and o about the central axis of the egt are summed to zero; that is 0=+++ ozyx tttt (20) where ti denotes an external torque exerted on link i. similarly, it is well-known that the net power flowing into the system via the four coaxial links are summed to zero; that is 0.... =+++ oozzyyxx tttt ωωωω (21) eliminating zt from equations (20) and (21) and making use of eq. (12), and after simplification, yields y z oy x z ox o trtrt .. ,, −−= (22) similarly, eliminating to from equations (20) and (21) and making use of eq. (12), yields y z oy x z ox z trtrt ).1().1( ,, −+−= (23) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� equations (22) and (23) relate torques exerted by links x, y, z and o in terms of the velocity ratios r z ox , and r z oy , . each-link torque analysis of two-input egts the torque and power equilibrium equations can be written for an n-link egt as follows: • first, writing equations (18) and (19) once for each fundamental circuit will result in 2(n-2) equations. • second, at each node, applying the condition that the sum of torques on the link is equal to zero will result in n-node equations. a total of (3n-4) linear equations are obtained which can be written in a compact form by using a matrix-vector notation as [ ] [ ] [ ]in ba ttn =× (24) where [ ] ba n × is a system of (a×b) matrix whose elements are functions of the gear size ratios (ngb,ga), and [ ]t denotes the vector of (b) torques. hence, regardless of which links are assigned as the input, output, or fixed link, eq. (24) can be used to solve for the (b) unknown torques in terms of the input torques [ ] in t . these methodologies are perhaps best illustrated through a design example. case studt: multi-rider human powered vehicle epicyclic gear trains are considered as the most effective method for coupling the relatively inconsistent inputs of two human riders (corey, 2003). what follows is the design of such a gear train using the present new methodologies. the first step in the design process is to set fourth any design constraints on the design. design constraints in this paper, several requirements must be met for the design to be viable. these are the same as those in (corey, 2003): 1. the drivers are to be seated with their backs to one another. this means that at the system's operating point, the two inputs rotate in opposite directions, ωi1 / ωi2 < 0. 2. the output link moves slightly above the nominal pedal cadence of 80 rpm pedal velocity associated with efficient riding 80 ≤ | ωo | ≤ 120. 3. both riders pedal at approximately the same velocity and contribute approximately the same percentage of the output power. plan 1 an egt with one carrier and three coaxial gears meshing with one planet is shown in fig. 5. assume that the sizes of the sun gears are in the descending order of gear 2 > gear 1. selecting three out of the four coaxial links (1, 2, 4, 5) at a time, yields four sets of three coaxial links (1, 2, 4),(1, 5, 4),(2, 5, 4) and (1, 2, 5). for the coaxial links (1, 2, 4), and making use of eq. (12), the velocity ratio r 4 2,1 can be found as 12 3 21 3 2, 2 3 1, 1 34 2,1 . . zz zz n n r == (25) it can be shown that 14 2,1 >r . for the coaxial links (1, 5, 4), and making use of eq. (12), we can find al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 12 3 51 3 5, 2 3 1, 1 34 5,1 . . zz zz n n r −== (26) it is apparent that r 4 5,10 > . in a similar way, we can find that r 4 5,20 > and 1 5 2,1 >r . all other velocity ratios and velocity ratio inversions can be found from table 1. these are used to construct table 3. to search for an appropriate assignment of the four coaxial links, one can examine, in general the first and second design constraints which can be written in notation consistent with that used in table 2 as randrr z yx z ox z oy ,,, 001 >>>> (27) where y and o rotate in the same direction and x rotates in the opposite direction. by searching in table 3 for the velocity ratio ranges that satisfy eq. (27), only two possible solutions can be found: 1. rr 4 1,5 4 1,2 01 >>> , which gives x = 5, y = 2, o = 1 and z = 4,and 2. rr 2 5,1 2 5,4 01 >>> , which gives x = 1, y = 4, o = 5 and z = 2 these two assignments are the potential candidates for achieving a proper design. after establishing a broad range of r-ranges to be considered, the next task is to attempt to apply the design constraints to the governing equations of the system. examining the third design constraint, it is convenient to write it in the form yyxx tt ωω .. = (28) or 1−== x y y x t t ω ω (29) obviously, since eq. (22) must hold for the power contribution from each rider to be equal, and the input torques are equal and opposite, the velocity ratios are related after simplification by rr z oy z ox ,, −= (30) and from eq. (14) and the first and third design constraints, we get 1, −=r z yx (31) since the human body provides most efficient power at a nominal pedal cadence of 80 rpm pedal velocity associated with efficient riding (corey, 2003), it would be advantageous to select a gear ratio that would place the absolute value of the output velocity in the range of 120 rpm, as required by the second design constraint. that is 32, =r z oy (32) and 32, −=r z ox (33) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� applying eq. (31) to the first potential solution and simplifying, we get zzr 52 4 2,5 −= (34) since 5 z is larger than 2 z , and then r 4 2,5 can never be equal to minus unity, which will fail the third design constraint requiring that, the power contribution from each rider to be equal. applying eq. (31) to the second potential solution and simplifying, we get 1)..(1 123213 2 4,1 −=−= zzzzr (35) after more simplification, we get 2.. 123213 =zzzz (36) applying equations (32) and (33) and simplifying, we get 32)( 525 2 5,4 =+= zzzr (37) and 32 2 2 3 5 2 3 2 2 3 1 1 3 2 5,1 −= + + − = z z z z z z z z r (38) also, from geometric considerations with all gears having the same diametrical pitch, 22 3 11 3 zzzz +=+ (39) and 2 3 25 .2 zzz += (40) the solution of equations (36), (37), (38), (39) and (40) is listed in table 4. plan 2 this design adopts the compound egt shown in fig. 6 to achieve the two-input velocity changer. assume that the sizes of the sun gears are in the descending order of gear 4 > gear 3² > gear 3¹. selecting three out of the four coaxial links (1, 2, 3, 4) at a time, yields four sets of three coaxial links (1, 2, 3),(2, 3, 4),(1,4,2) and (1, 3, 4). for the coaxial links (1, 2, 3), and since they belong to the same fge, then making use of eq. (12), we can find )()( 1 3 51 2 5 1 3 5 1 3,5 1 2,5 1 3,53 2,1 zzzz zz nn n r + = − − = (41) it can be shown that 01 3 2,1 >> r . al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� for the coaxial links (2, 3, 4), and since they belong to the same fge, then making use of eq. (12), we can find )()( 42 6 2 36 42 64 3,2 1 zzzz zz r +− = (42) it is apparent that r>0 4 3,2 . the velocity ratios of the remaining two sets of three coaxial links can be expressed in terms of the velocity ratios of the above two fges. we use the fact that 01 3 2,1 >> r and r>0 4 3,2 to begin our evolution. by assigning x = 1, y = 3, z = 4 and o = 2 in table 2, we can write 01 3 2,1 >> r and r>0 4 2,3 from kinematic inversions. for this assignment the velocity ratio r 4 3,1 can assume two possible ratio ranges, r>0 4 3,1 and 01 4 3,1 >> r . if r>0 4 3,1 , then 01 4 2,1 >> r . also, if 01 4 3,1 >> r then r 4 2,10 > . two sets of velocity ratio ranges are possible: 1. 01 3 2,1 >> r , r>0 4 3,2 , r 4 3,10 > and 01 4 2,1 >> r , and 2. 01 3 2,1 >> r , r>0 4 3,2 , 01 4 3,1 >> r and r>0 4 2,1 . any assignment of the four coaxial links that gives two known velocity ratios will give similar results. all other velocity ratios can be found from the kinematic inversions of table 1. two different tables can be constructed for the above two sets. these are shown in tables 5 and 6 (only the first will be considered). by searching in table 5 for the velocity ratio ranges that satisfy eq. (27), two possible solutions are found: 1. 4 2,3 4 2,1 01 rr >>> , which gives x = 3, y = 1, o = 2 and z = 4, and 2. 1 3,2 1 3,4 01 rr >>> , which gives x = 2, y = 4, o = 3 and z = 1. again, only the first solution will be considered. applying eq. (33) and simplifying, we get 32 . . 1 2 3 2 6 41 64 2,3 −=−= zz zz r (43) after more simplification, we get 35 . . 2 3 2 6 41 6 = zz zz (44) applying eq. (32), we get al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 32.11 2 4,3 2 3,1 2 4,1 4 2,1 =−=−= rrrr (45) but 35 . . 1 2 3 2 6 41 64 2,3 2 4,3 ==−= zz zz rr (46) making use of eq. (41), we can write 1 3 1 2 1 33 2,1 2 3,1 1 zz z rr + =−= (47) substituting equations (46) and (47) into eq. (45), and simplifying, we get 1 3 1 2 .4 zz = (48) applying eq. (31), we get 1.11 3 4,2 3 2,1 3 4,1 4 3,1 −=−=−= rrrr (49) re-arranging, eq. (49) 3 4,2 3 2,1 2 r r = (50) but 25)1( 4 2,3 4 2,3 3 4,2 =−= rrr (51) and )( 131212 3 2,1 zzzr += (52) substituting equations (51) and (52) into eq. (50), and simplifying, we arrive again at eq. (48). also, from geometric considerations 2 3 1 6 42 6 zzzz +=+ (53) and 51 3 1 2 .2 zzz += (54) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� the solution of equations (44), (48), (53) and (54) is listed in table 7 for 1623 =z . torque and power-flow analysis the corresponding fundamental-circuit diagram for the egt shown in fig. 6 is sketched in figure7. the gear ratios for this train are 5.1 353,5 1 −=−= zzn (55) 375.0 252,5 1 == zzn (56) 1 363,6 21 −=−= zzn (57) 6.0464,6 2 −=−= zzn (58) writing eqs (18) and (19) once for each fundamental circuit, yields the following eight linear equations: 0. 313,551 =+ tnt (59) 0).1( 313,511 =−+ tnt (60) 0. 222,552 =+ tnt (61) 0).1( 222,512 =−+ tnt (62) 0. 333,663 =+ tnt (63) 0).1( 333,623 =−+ tnt (64) 0. 444,664 =+ tnt (65) 0).1( 444,624 =−+ tnt (66) summing all the torques acting on each node to zero, yields the following six linear equations 06463 =+ tt (67) 03331 =′′++ inttt (68) 05251 =+ tt (69) 044 =+ rtt (70) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 0242322 =+++ otttt (71) 01211 =′++ inttt (72) hence, a system of fourteen linear equations is obtained which can be solved for the fourteen unknowns in terms of the first input torque int ′ , the second input torque int ′′ , and the gear size ratios. equations (59) through (72) can be arranged in a matrix form as: )73( 0 0 0 0 0 0 0 0 0 0 0 0 00000000000011 10000000011100 01000010000000 00001100000000 00000001100000 00110000000000 00000000000625.010 00001000000375.000 000000005.200001 000001005.100000 00000002001000 00010001000000 0000006.10010000 0010006.00000000 64 63 52 51 44 33 31 24 23 22 12 11                                   ′− ′′−                                                                     = + − + − + − in in o r t t t t t t t t t t t t t t t t the solution of eq. (73) is listed in table 8. the torque flow through the egt is shown in fig. 8. the power-flow through the egt is shown in fig. 9. the second input power transmits through the entire gear train whereas the first input power transmits through links 3, 6 and 2 only. the two riders will supplement each other and a constructive power balance is achieved through the train. now, it is apparent that the reaction link is used in two-input egts to control the direction of rotation of other links and thus the direction of the power-flow. conclusions 1. this paper presents a unification of kinematic and torque balance methods for the analysis of two-input epicyclic-type transmission trains. 2. a new method for the derivation of the velocity ratio of egt in a symbolic form has been developed. a single kinematic equation has been derived to study the kinematic characteristics of fges. 3. the results have been used for the estimation and comparison of various velocity ratios of egms, which lead to the development of a methodology for the assignment of the various links for a given two-input egm. 4. twelve velocity ratio relations have been derived for any four coaxial links of an egt. these velocity ratio relations are three more than the nine relations given in (hsieh and tsai, 1996b). this is because that paper has not taken in consideration the effect of certain velocity ratio ranges on the velocity ratio relations. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� 5. this study contributes to the development of a systematic methodology for the torque and power flow analyses of two-input epicyclic gear mechanisms (egms) with a reaction link, based upon the concept of fundamental circuit. reaction links are used in two-input egts to control the direction of rotation of other links and thus the direction of the power-flow. 6. specifically, this study has presented for the first time a complete design and analysis of two-input velocity changer to be used as a power coupling in a new generation of tandem bicycles. two new designs have been demonstrated. references [1] allen, r. r., 1979, "multi-port models of the kinematic and dynamic analysis of gear power transmission", asme j. of mechanical design, volume 101, pp. 258-392. [2] buchsbaum, f., and freudenstein, f., 1970, "synthesis of kinematic structure of geared kinematic chains and other mechanisms," journal of mechanisms and machine theory, vol. 5, pp. 357-392. [3] chatterjee, g., and tsai, l. w. , 1995, " enumeration of epicyclic-type transmission gear trains, " transactions of sae, vol. 103, sec. 6, paper no. 941012, pp. 1415-1426. [4] chatterjee, g., and tsai, l. w., 1996, "computer-aided sketching of epicyclic-type automatic transmission gear trains," transactions of the asme, journal of mechanical design,, vol. 108, no. 3, pp. 405-411. [5] corey , c. a., 2003, "epicyclic gear train solution technique with application to tandem bicycling ," thesis (m. sc.) , department of mechanical engineering , virginia polytechnic institute and state university , blacksburg , va, usa. [6] esmail, e. l., 2007, "nomographs for design of planetary gear trains", accepted for publication in the journal of king abdulaziz university-engineering sciences, s. a. [7] freudenstein, f., 1971, "an application of boolean algebra to the motion of epicyclic drives," asme journal engineering for industry, vol. 93, pp. 176-182. [8] freudenstein, f., and yang, a. t., 1972, "kinematics and statics of coupled epicyclic spur gear trains", j. of mechanism and machine theory, volume 7, pp. 263-275. [9] gibson, d. and kramer, s., 1984, "symbolic notation and kinematic equations of motion of the twenty-two basic spur planetary gear trains", asme j. of mechanisms, transmissions and automation in design, volume 106, pp. 333-340. [10] gott, p. g., 1991, "changing gears," society of automotive engineers, inc., warrendale, pennsylvania. [11] hsieh, h. l., and tsai, l. w., 1996a, "kinematic analysis of epicyclic-type transmission mechanisms using the concept of fundamental geared entities", asme j. of mechanical design, volume 118, pp. 294-299. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� [12] hsieh, h. i., and tsai, l. w., 1996b,"a methodology for enumeration of clutching sequences associated with epicyclic-type automatic transmission mechanisms", sae transactions, journal of passenger cars, sec.105, pp. 928-936. [13] hsieh, h. l., and tsai, l. w., 1998, "the selection of a most efficient clutching sequence associated with automatic transmission," asme j. of mechanical design, volume 120, pp. 514519. [14] levai, z., 1964, "theory of epicyclic gears and epicyclic change-speed gears", doctoral dissertation, budapest. [15] levai, z., 1968, "structure and analysis of planetary gear trains", journal of mechanisms, volume 3, pp. 131-148. [16] mruthyunjaya, t.s., and ravisankar, r., 1985, "computerized synthesis of the structure of geared kinematic chains," journal of mechanisms and machine theory, vol. 20, pp. 368-387. [17] nazim, m-n. , and hussaini ,s. , 2005," new intelligent transmission concept for hybrid mobile robot speed control ,"int. j. of advanced robotic systems, volume 2, no. 3, pp, 259-263. [18] olson, d. g. , erdman, a. g. , and riley, d. r. , 1991, "topological analysis of singledegree of freedom planetary gear trains," asme journal of mechanical design, vol. 113, pp. 1016. [19] pennestri, e., and freudenstein, f., 1993, "a systematic approach to power-flow and static force analysis in epicyclic spur-gear trains", asme j. of mechanical design, volume 115, no. 3, pp. 639-644. [20] pennestri, e., and freudenstein, f., 1993, "the mechanical efficiency of epicyclic gear trains", asme journal of mechanical design, volume 115, no. 3, pp. 645-651. [21] smith, d., 1979,"analysis of epicyclic gear trains via the vector loop approach," proc. sixth applied mechanisms, paper no. 10. [22] saggora, l. and olson, d. g., 1992,"a simplified approach for force and power-flow analysis of compound epicyclic spur-gear trains," proc. of the asme 1992 design technical confs. advances in design automation, de-vol. 44-2, vol. 2, pp. 83-89. [23] willis, r. j., 1982, "on the kinematic of the closed epicyclic differential gears", asme j. of mechanical design, volume 104, pp. 712-723. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� table 1: velocity ratio inversions and ranges. velocity ratios r z yx , r z xy , r y zx , r y xz , r x zy , r x yz , velocity ratio inversions e 1/e 1-e 1/(1-e) (e-1)/e e/(e-1) e>1 1>1/e>0 0>1─e 0>1/(1─e) 1>(e─1)/e>0 e/(e─1)>1 1>e>0 1/e>1 1>1─e>0 1/(1─e)>1 0>(e─1)/e 0>e/(e─1) velocity ratio ranges 0>e 0>1/e 1─e>1 1>1/(1─e)>0 (e─1)/e>1 1>e/(e─1)>0 table 2: velocity ratio relations for any four coaxial links of an egt. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� table 3: velocity ratio ranges for the egt shown in fig. 5. r 4 5,10 > r 4 1,50 > 1 5 4,1 >r 01 5 1,4 >> r 1 1 4,5 >r 01 1 5,4 >> r r 4 5,20 > r 4 2,50 > 1 5 4,2 >r 01 5 2,4 >> r 1 2 4,5 >r 01 2 5,4 >> r 14 2,1 >r 01 4 1,2 >> r r 2 4,10 > r 2 1,40 > 01 1 4,2 >> r 1 1 2,4 >r 15 2,1 >r 01 5 1,2 >> r r 2 5,10 > r 2 1,50 > 01 1 5,2 >> r 1 1 2,5 >r table 4: number of teeth on the gears of the first design. teethz 181 = 242 =z 485 =z 18 1 3 =z 12 2 3 =z table 5: first velocity ratio ranges for the compound egt shown in fig. 6. 01 3 2,1 >> r 1 3 1,2 >r 01 2 3,1 >> r 1 2 1,3 >r r>0 1 3,2 r 1 2,30 > r 4 3,20 > r>0 4 2,3 1 3 4,2 >r 01 3 2,4 >> r 1 2 4,3 >r 01 2 3,4 >> r r 4 3,10 > r>0 4 1,3 1 3 4,1 >r 01 3 1,4 >> r 1 1 4,3 >r 01 1 3,4 >> r 01 4 2,1 >> r 1 4 1,2 >r 01 2 4,1 >> r 1 2 1,4 >r r>0 1 4,2 r 1 2,40 > table 6: second velocity ratio ranges for the compound egt shown in fig. 6. 01 3 2,1 >> r 1 3 1,2 >r 01 2 3,1 >> r 1 2 1,3 >r r>0 1 3,2 r 1 2,30 > r 4 3,20 > r>0 4 2,3 1 3 4,2 >r 01 3 2,4 >> r 1 2 4,3 >r 01 2 3,4 >> r 01 4 3,1 >> r 1 4 1,3 >r 01 3 4,1 >> r 1 3 1,4 >r r 1 4,30 > r>0 1 3,4 r>0 4 2,1 r>0 4 1,2 1 2 4,1 >r 01 2 1,4 >> r 1 1 4,2 >r 01 1 2,4 >> r table 7: number of teeth on the gears for the second design. 4812 =z 1213 =z 1623 =z 204 =z 185 =z 1616 =z 1226 =z table 8: torque distribution of the egt shown in fig. 6 when links 4, 2, 1 and 3 serve as the fixed, output, first input and second input links, respectively. intt ′−= 5.011 inin ttt ′′′ += 6667.13333.044 intt ′−= 5.012 intt ′= 3.051 intt ′= 8.022 intt ′−= 3.052 inin ttt ′′′ += 24.023 inin ttt ′′′ −−= 2.063 inin ttt ′′′ −−= 6667.25333.024 inin ttt ′′′ += 2.064 intt ′= 2.031 ininr ttt ′′′ −−= 6667.13333.0 inin ttt ′′′ −−= 2.033 inino ttt ′′′ +−= 6667.06667.0 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure 1: a basic epicyclic gear train with its canonical graph representation. figure 2: a basic gear pair and its schematic representation. figure 3: a typical single-planet fgt. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� figure 4: a typical double-planet fgt. figure 5: epicyclic gear train to be used in the first plan. figure 6: compound epicyclic gear train to be used in the second plan. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� figure 7: fundamental-circuit diagram of the egt shown in fig. 6 when links 4, 2, 1 and 3 serve as the fixed, output, first input and second input links, respectively. figure 8: torque flow through the egt shown in fig. 6 when links 4, 2, 1 and 3 serve as the fixed, output, first input and second input links, respectively. figure 9: powerflow through the egt shown in fig. 6 when links 4, 2, 1 and 3 serve as the fixed, output, first input and second input links, respectively. article al-qadisiyah journalfor for engineering sciences 15 (2022) 157–164 contents lists available athttp://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: mohamed.aldawody@qu.edu.iq (mohamed aldawody) https://doi.org/10.30772/qjes.v15i3.828 2411-7773/© 2022 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. the combustion characteristics of compression ignition engine fuelled partially by lpg-diesel blends (simulation study) maysaa j. mohsen* and mohamed f. al-dawody department of mechanical engineering, university of al-qadisiyah, al-qadisiyah, iraq a r t i c l e i n f o article history: received 25 may 2022 received in revised form 8 july 2022 accepted 10 september 2022 keywords: dual fuel lpg nox emission diesel -rk a b s t r a c t this paper proposes a numerical investigation of the behavior of the dual diesel-liquefied petroleum gas (lpg) engine. numerical analysis is performed with the aid of the simulation program diesel-rk. three volumetric lpg blends: 5 % lpg, 8 % lpg, and 10%lpg are inducted with air intake for a single cylinder,4-stroke, constant speed diesel engine with a fixed compression ratio of 15.5/1. no dramatic change in combustion pressure is seen for 5%,8%, and 10% lpg compared to the case of 0% lpg (diesel only). diesel's maximum energy production is 32.53 (1/deg.) at 365 degrees btdc, and this is lowered to 30.28 (1/deg.) at the same crank angle when using 10% lpg. maximum temperature and pressure rise a little bit by 0.14 % and 0.41 % for 10 % lpg. increasing the lpg injection rate reduces volumetric efficiency and mechanical efficiency slightly. the results found a slight increase in nox and a considerable reduction is captured in bosch smoke number (bsn) when lpg is used with diesel. the obtained is validated with the findings of other researchers. ©2022 university of al-qadisiyah. all rights reserved. 1. introduction improvements in diesel engine fuel efficiency have led to its widespread use in recent years as a primary propulsion source across industries. due to their high power output and low cost, diesel fuel engines have become popular in many domains [1]. despite their fuel economy, diesel engines have certain disadvantages, including higher nox and particulate emissions. [2] so, alternative fuels could be used instead of traditional diesel to cut down on pollution [3]. liquefied petroleum gas (lpg) is a viable alternative fuel for diesel engines. because it has the potential to drastically reduce pollution emissions (particularly nitrogen oxides (nox) and smoke) without compromising engine performance.[4]. gaseous lpg, often known as "autogas," is a byproduct of refining petroleum and consists mostly of propane, propylene, butane, and other light hydrocarbons [5-7]. it can only be used in the ci engine in dual fuel mode, and a substantial study has been conducted in this way. it results in improved performance as well as lower particle and smoke emissions [8]. since diesel fuel and lpg are both suitable for this engine, we call it a "dual fuel" engine. lpg and air are either mixed directly in the intake manifold or injected into the engine's cylinders [9]. dual fuel operation increased specific fuel consumption http://qu.edu.iq/ mailto:mohamed.aldawody@qu.edu.iq https://doi.org/10.30772/qjes.v15i3.828 https://doi.org/10.30772/qjes.v15i3.828 http://creativecommons.org/licenses/by/4.0/ 158 maysaa j. mohsen and mohamed f. al-dawody /al-qadisiyah journalfor engineering sciences15 (2022) 157–164 relative to diesel operation. also, when comparing pure diesel operation to dual-fuel operation, we find that the latter reduces emissions of nitric oxide and soot, though it also increases emissions of carbon monoxide [10]. because the engine may use either liquid or a combination of liquid and gaseous fuel, it can be used in a range of situations, making the dual-fuel idea very desirable [3]. a high octane number prevents lpg from igniting during the compression stroke (high self-ignition temperature).but it ignites fast when blended with a fuel that has a lower octane rating (such as diesel) [11]. when more lpg is put into the engine, the power and performance both get better, and the emissions go down. lpg can only be used in diesel engines as a dual fuel because it has a low cetane number and is hard to use in large amounts [12]. the gaseous lpg fuel phase may be injected into diesel engines through the intake manifold[13]. because the pumping pressure is more than 0.5 mpa, at higher pressure, diesel moves from the gas phase into the liquid phase. lpg has a low boiling point, so when it's pumped into the cylinder, it evaporates and helps spread out the fuel spray [14-15]. there have been several studies conducted on lpg–diesel dual-fuel engines, vezir ayhan et al[16]. emissions and performance indicators of a normally aspirated four-stroke diesel engine with a single cylinder were measured while the engine was exposed to lpg injection during the air input phase. after figuring out the best lpg mix for dual operation, designers made an electrical device to inject the fuel. 5 %, 10%, 15 %, and 25 % lpg injection rates were established by mass. the results showed that the best sfc and brake thermal efficiency occurred at 15% lpg and engine speeds between 1400 and 1800 rpm. optimal exhaust gas emission levels and engine performance were achieved with a 5% lpg injection rate d.h. qi[17]. the combustion of lpg and diesel is being investigated. by increasing the lpg energy, the peak cylinder pressure, the pressure rise rate, and the heat release rate are all decreased under modest engine loads. at 25% lpg energy content and maximum engine loads, these characteristics are at their maximum. the study indicated that when the amount of lpg was increased, the ignition delay time and combustion duration also rose while the engine was operating under light load. however, they first rise and then fall with increased engine loads. each engine load corresponds to an output of lpg energy. dual-fuel operation is only detrimental at mild loads while being more efficient than diesel. le and the nguyen[18] experimented with a modified one-cylinder diesel engine fuelled by diesel and lpg to assess its combustion and environmental effects. due to the knocking limit being reached at low engine speeds, the maximum lpg replacement happens under full load. dual-fuel engines, however, save the most money when driven quickly. specifically, lpg is at 54% at 2000 rpm but lowers to 40% at higher speeds. qi et al[19] the performance and pollution of a diesel engine with a single cylinder and di were studied experimentally to determine the effect of lpg-diesel mixed fuel combustion. an increase in lpg mass fraction reduces peak pressure in the cylinder and delays ignition. emissions of nitrogen oxide (nox), hydrocarbons (hc), and carbon monoxide (co) all decrease at high engine loads this research looked examined the effects of different loads on a constant speed, single-cylinder, four-stroke diesel engine's performance, combustion characteristics, and emissions. while increasing at low loads when lpg mass fraction is low. rao. et al.[20] mechanical and brake thermal efficiency decreases as lpg percentage increases below 20% of engine load, but increases above this load (80%). reduced volumetric efficiency, however, with an increasing lpg percentage in both engine load states. when looking at emissions, it was found that increasing the content of lpg led to higher concentrations of both hc and co. conversely, there has been a reduction in smoke density and nitrogen oxide (nox) emission. elnagjjar et al[21] using a variety of lpg compositions (propane/butane volume ratios of 100:0, 70:30, 55:45, 25:75, and 0:100), the efficiency of a normally aspirated, directly injected diesel engine is evaluated and compared. the results show that, while lpg composition has little effect on engine performance, it has a significant impact on the number of exhaust emissions. proportions of 50/50 propane and butane are more efficient than either gas alone. ronald and somasundaram[22] by replacing some of the diesel with lpg, the thermal and mechanical efficiency of a diesel engine may be increased by around 5 % while specific fuel consumption is reduced by about 33 % and carbon monoxide emissions are reduced by about 13 %. however, when using a fuel mixture of 60% lpg and 40% diesel, both nox and co2 emissions were reduced by 35% and 67%, respectively. vijayabalan and nagarajan[23] it was found that the diesel engine's characteristics were improved by installing a glow-plug within the combustion chamber under low load, with increases in braking thermal efficiency of 3% and decreases in hc emissions of 69%, co emissions of 50%, and smoke emissions of 9%. rimkus et al.[24] the use of lpg and its impact on the performance and environmental impact of a turbocharged, four-stroke, compressionignition engine is under study. blending lpg with diesel decreased engine efficiency, according to the study authors, since it decreased the quantity of diesel supplied to the cylinder and delayed the diesel injection moment. the addition of lpg increased both co and hc levels in the exhaust emissions while reducing nox and carbon monoxide levels. giang and son[25] change the amount of lpg in diesel fuel in a toyota 3cte diesel engine and see how it affects performance and pollution. when they used a dual fuel configuration, they saw that the engine's normal torque and output went down, but not by a huge margin compared to when it was running on 100% diesel and producing 98.5% and 85% of its maximum torque and power, nomenclature ao, a2, a3 bsfc bsn ca ci co co2 df di efm constants brake specific fuel consumption bosh smoke number crank angle degrees compression ignition engine carbon monoxide carbon dioxide diesel fuel direct injection elementary fuel mass hc lng lpg nox p pi ps vc x xo hydrocarbons liquefied natural gas liquefied petroleum gas nitrogen oxides cylinder pressure (pa) prediction interval saturation vapor pressure of fuel the volume of a cylinder percentage of heat release the proportion of fuel vapor generated during the delay interval maysaa j. mohsen and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences15 (2022) 147–164 159 respectively. in all modes of operation, nox and smoke emissions are reduced, while co and hc emissions are greatly increased. anye [26] we used a one-dimensional model developed in avl boost to conduct a numerical analysis of the performance characteristics and associated pollutants of dual-fuel (diesel-lpg) under various operating regimes and fuel (diesel-lpg) mass ratios. at maximum lpg content (70% diesel, 30% lpg) and engine speed (2435 rpm), the maximum cylinder pressure for a pure diesel engine is raised by 21.07%. furthermore, power increased linearly when the lpg mass ratio was increased from 10% to 30%. with a higher lpg mass ratio, nox emissions are reduced. hadi and qadir[27] researchers tested using varying percentages of iraqi lpg (from 10% to 25%) with varying percentages of iraqi gas-oil fuel while keeping the thermal load constant to determine the possibility of reducing pollutant emissions. combining lpg and gas–oil as well as air mass flow uncommon, the rota-meter regulates the mass flow rate to reach a set temperature. incomplete combustion was indicated by a 3% rise in co, soot, and uhc levels with an increase in the equivalency ratio and a 2.5% decrease in co2 and nox levels owing to the lower oxygen ratio in the mixture. helin xiao et al.[28] analysis and modeling of spray and combustion parameters of lpg, diesel, and 30% and 50% lpg/diesel blends were conducted. for numerically computing the spray properties, we use the kiva–3v approach and apply it to a high-pressure constantvolume container and high-speed photography. compared to diesel, lpg results in a smaller spray angle and a shorter spray combustion duration. spray loses efficiency as air pressure increases. the numerical results were in agreement with the observational data within very small margins. but the low sensitivity of the imaging equipment when used at high speeds led to results that did not match what was expected at the late injection point.albert boretti[29]. the performance of a diesel–lpg engine with two main injectors in each cylinder was analyzed numerically. analytical results are presented for a high-speed direct-injection turbocharged diesel engine with a displacement of 1600 cc running throughout a wide speed and load range on both diesel and lpg. direct injection of lpg into the engine is made possible by adding a new injector to each cylinder. the purpose of this research is to determine how much pilot/per diesel fuel energy is needed to power a diesel engine in a way similar to combustion with lpg primary injection. the purpose of this study is to examine the characteristics of a diesel engine running on a dual-fuel lpg-diesel setup with the help of simulation software diesel-rk. 2. the materials and methods in this study, liquefied petroleum gas (lpg) was used as a replacement for diesel in an effort to lower diesel engine emissions. gaseous liquid petroleum gas (lpg) was utilized as the primary fuel, with diesel serving as the secondary fuel while operating in dual fuel mode. the current study compared three different lpg flow rates (5%, 8%, and 10%). the characteristics of diesel and lpg fuel are compared in table 1. 3. properties and composition of iraqi lpg when considering the many clean gaseous fuels on the market, including lpg, lng, and dme (dimethyl-ether), lpg stands out as one of the most promising alternatives. [30]. lpg is made from hydrocarbons created during crude oil refining and heavier natural gas components[31]. propane (c3h8) is the most common component of lpg, however variable quantities of butane (c4h10) are used depending on the geographical region, season, and production technique. beyond propane and butane, lpg may also include trace quantities of other hydrocarbons[5]. table 1 presents the properties of iraqi lpg and diesel[24]. because of its wide supply infrastructure and higher heating value, lpg is a viable alternative fuel. since it has a higher octane value, lpg has benefits in terms of operating characteristics at high compression ratios[32]. at the low-pressure range of (0.7–0.8) mpa, it may liquefy at room temperature. due to its lower density and better stoichiometric (fuel/air) ratio, lpg may reduce specific fuel consumption compared to petro-diesel. since lpg has a greater calorific value than petro-diesel, an lpg-fueled engine using the same equivalency ratio as a petro-diesel-fueled engine might provide more effective power[33,34]. by comparison, the emissions of greenhouse gases and other pollutants that are controlled by law are reduced when lpg is used. furthermore, lpg's greater ignition temperature than diesel slows the fuel's auto-ignition, preventing knocking[35]. the diesel engine shown in table 2 is the subject of mathematical analysis. table1 diesel fuel and liquefied petroleum gas properties [24] table 2 specifications for engine [36] engine make kirloskar diesel engine engine type 4 stroke, single-cylinder bore × stroke 80 mm× 110 mm compression ratio 15.5 rated output 3.7kw injection pressure 160 bar injection timing 20 ca btdc properties iraqi diesel 5%iraq i lpg 8%iraqi lpg 10%iraq i lpg formula c13.775h2 4.7 c13.24h24 .2 c12.92h23. 97 c12.7h23.77 molecular mass 190 183.147 179.036 176.295 density (kg/m3) 830 788.606 763.77 747.056 lower heating value(mj/kg) 45.83 45.855 45.866 45.874 stoichiometric a/f ratio(kg/kg) 14.406 14.463 14.493 14.519 160 maysaa j. mohsen and mohamed f. al-dawody /al-qadisiyah journalfor engineering sciences15 (2022) 157–164 4. lpg/diesel dual-fuel. similarly to a spark-ignited engine, the air-lpg intake mixture is forced into the cylinder and compressed to increase the temperature and pressure. a little quantity of pilot diesel fuel is injected at the end of the compression stroke to ignite the mixture. this ignition source is a pilot injection. the lpg gas-air combination ignites in many places around the injected diesel spray, creating several flame fronts. the result is a rapid and easy start to the combustion process. [37]. 5. numerical modeling the diesel engine (detailed in table 2) was analyzed using the modeling program diesel rk to determine its performance characteristics when fueled by diesel and lpg mixes. in the works cited, details about the different equations used in the simulation are given[36,38]. 5.1 spray evaluation model when an elementary fuel mass (efm) is being moved from the injector to the spray tip in a very short time interval, its speed may be described by equation (1). figure 1 illustrates the spray's path over time: [ 𝑉 𝑉 𝑂 ] 3 2 = 1 − 𝑙 𝑙𝑚 (1) where: v: is the efm's current speed. 𝑉𝑂 : the initial efm speed at the injector nozzle 𝑙 : current distance between efm and the nozzle injector. 𝑙𝑚 : the distance between the beginning of an efm pulse and its end in front of a spray figure 1. the spray development over time[39] following is a solution to equation (1) 3𝑙𝑚 [1 − [ 𝑙 𝑙𝑚 ]0.333] − 𝑉𝑂 𝜏𝑘 = 0 (2) where, 𝜏𝑘 is the time required for the efm to travel l distance from the nozzle injector, when the efm is turned off at the spray nozzle 𝑙 = 𝑙𝑚 and 𝜏𝑘 = 𝜏𝑚. where, 𝜏𝑚: there is travel time for the efm to the quantity at the front of the spray before it ends. equation (2) can also be rewritten as follows: 𝑙𝑚 = 𝑉0 𝜏𝑚 3 (3) equations (1) and (2) may be used to determine the speed and length of efm at any given time. 𝑉 = 𝑉0{1 − 𝜏𝑘 𝜏𝑚 }2 (4) 𝑙 = 𝑙𝑚 [1 − [1 − 𝜏𝑘 𝜏𝑚 ]3] (5) 5.2 model for releasing heat the combustion process is separated into four phases, each with its own chemical and physical characteristics that limit the rate of burning. the stages are shown here. 1. ignition delay interval phase: 𝝉 = 𝒆 ( 𝑬𝒂 𝟖.𝟑𝟏𝟐𝑻 − 𝟕𝟎 𝑪𝑵+𝟐𝟓 ) ∗ √ 𝑻 𝑷 ∗ 𝟑. 𝟖 ∗ 𝟏𝟎−𝟔 ∗ (𝒏 ∗ 𝟏 − 𝟏. 𝟔 ∗ 𝟏𝟎−𝟒) (6) 2. combustion of a combination of air and fuel vapor produced by premixed combustion phase : 𝒅𝒙 𝒅𝒕 = 𝝋𝟏 { 𝒅𝝈𝒖 𝒅𝝉 } + {𝑨𝟎 ∗ (𝟎. 𝟏𝝈𝒖𝒅 + 𝒙𝟎 )(𝝈𝒖𝒅 − 𝒙𝟎) ( 𝒎𝒇 𝑽𝒊 )} ∗ 𝝋𝒐 (7) 3. a phase of diffuse combustion (a direct injection of fuel is then burnt): 𝒅𝒙 𝒅𝝉 = 𝝋𝟐 ∗ {(∅ − 𝒙)(𝝈𝒖 − 𝒙) ∗ { 𝒎𝒇 𝑽𝒄 } ∗ 𝑨𝟐} + 𝝋𝟏 ∗ { 𝒅𝝈𝒖 𝒅𝝉 } (8) 4. a phase of late combustion (fuel combustion after injection is complete): 𝒅𝒙 𝒅𝝉 = 𝑲𝑻 ∗ 𝑨𝟑 ∗ (𝝐𝒃 ∅ − 𝒙)(𝟏 − 𝒙) ∗ 𝝋𝟑 (9) 𝜑𝑜 = 𝜑1 = 𝜑2 = 𝜑3 is a function representing the end of fuel vapor combustion in different regions: 𝝋 = 𝟏 − [ 𝑨𝟏 ∈𝒃 ∗∅ − 𝒙] 𝒅𝒙 𝒅𝒕 {∑ [𝟑𝟎𝟎 ∗ 𝒓𝒘𝒊 𝒎𝒘 𝒊=𝟏 ∗ 𝒆 ( −𝟏𝟔𝟎𝟎𝟎 𝒓𝒘𝒊+𝟐𝟓𝟎𝟎 ) ] + 𝒓𝒗} (10) where, 𝜖𝑏 : reveals the efficiency of air use, 𝑟𝑣 : the data show how different environmental zones and fronts vary in their evaporation rates, ∅: reflects the equivalence ratio,𝑟𝑤𝑖 : represents the relative rate of evaporation in different zones of the wall surface flow 5.3 modeling nox formation in a mixture of nitrogen dioxide (no2) and nitric oxide (no), (nox) emissions are produced. due to the fact that combustion in a dual-fuel engine is governed by temperature, the zeldovich mechanism is a generally accepted approach for nox generation. the following equations describe the main processes that govern the generation of no from molecular nitrogen during burning : 𝑂2 ↔ 2 𝑂 (11) maysaa j. mohsen and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences15 (2022) 147–164 161 𝑂 + 𝑁2 ↔ 𝑁𝑂 + 𝑁 (12) 𝑂2 + 𝑁 ↔ 𝑁𝑂 + 𝑂 (13) as seen in equation 13, the concentration of atomic oxygen influences the reaction rate. the no volume concentration is calculated using the following formula[40]. 𝒅[𝑵𝑶] 𝒅𝜽 = 𝟐.𝟑𝟑∗𝟏𝟎𝟕∗𝑷[𝟏−( [𝑵𝑶] [𝑵𝑶]𝒆 ) ]∗[𝑵𝟐 ]ₑ[𝑶]ₑ∗𝒆 −𝟑𝟖𝟎𝟐𝟎 𝑻𝒛 𝑹𝑻𝒛[𝟏+ [𝑵𝑶] [𝑶𝟐]ₑ ∗( 𝟐𝟑𝟔𝟓 𝑻𝒛 )𝒆 𝟑𝟑𝟔𝟓 𝑻𝒛 ] [ 𝟏 𝒓𝒑𝒔 ] (14) 5.4 concentration modeling of soot the term "soot" refers to a specific kind of very small black carbon particles. that forms when a vapor carrier is present. in most cases, it is the result of an incomplete hydrocarbon combustion process. the combustion process causes it to develop, oxidize, and increase. in ref[41].a thorough study on modeling soot is given. when the engine is running normally, the amount of soot in the exhaust can be described as: [𝐶] = ∫ 𝑑[𝐶] 𝑑𝜏 480 𝜃𝐵 𝑑𝜃 6𝑛 [ 0.1 𝑃 ]𝛾 (15) equation (16) is used to define particulate matter (pm) as a function of (bsn): [43] [𝑃𝑀] = [𝑙𝑛 10 10−𝐵𝑜𝑠𝑐ℎ ]1.206 ∗ 565 (16) 6. the validity of the model data generated by the program is double-checked against the findings of other researchers. all the same parameters and operation states are entered into the program's databases. figure 2 shows the spray development per time for diesel fuel. similar tendencies and good agreement with a variation of 5% are found. figure 3 demonstrates the history of diesel heat release rate for the present work and the work of qusay et al [43]. it is safe to say that diesel rk software is an effective simulation tool for studying ic engine combustion characteristics. 7. results and discussion the exhaust gas emissions were first measured with the diesel engine running on pure diesel fuel (d-100) before adding varying amounts of lpg to the fuel (5% lpg, 8% lpg, and 10% lpg) at 100% load (full load) at a steady engine speed of 1500 rpm figure 2. validation of diesel full-load spray tip penetration figure 3. validation of f diesel full-load heat-release rates figure 4. variation of cylinder pressure with crank angle. 162 maysaa j. mohsen and mohamed f. al-dawody /al-qadisiyah journalfor engineering sciences15 (2022) 157–164 7.1 a combustion analysis figure 4 this presents the change in cylinder pressures as a ratio of lpg injection rates. it is clear from the illustration that an increase in lpg use led to a pressure rise. injecting lpg into a mixture result in greater pressure since more energy is being delivered into the system. diesel fuel has a maximum operating pressure of 88.07 bar, with lpg the maximum pressure of 88, 88.38, and 88.43 for 5%, 8%, and 10% lpg, respectively. [43]. the release rate of heat is seen in figure 5. when lpg is mixed with diesel, the delay between ignition and combustion is cut down, so combustion can start sooner, and less heat is given off [45]. diesel's highest energy output is 32.53 (1/deg.) at 365 degrees btdc, however, at 365 degrees btdc, it is just 31.14, 30.76, and 30.28 (1/deg.). for lpg concentrations of 5%, 8%, and 10%, btdc is used. figure 5. rate of heat release history for diesel and lpg mixtures maximum temperature and pressure as a result of lpg addition are shown in figure 6. maximum pressure increased by 0.088%, 0.35%, and 0.41% at 5%, 8%, and 10% lpg concentrations, respectively, due to increased flame speed in the homogeneous mixture of air and lpg. the maximum temperatures reached their highest point at 10% lpg. figure 6. effect of varying lpg on the maximum (pressure and temp.) figure 7 presents the impact of lpg concentration on ignition delay and combustion duration. upon adding lpg the ignition delay is decreased by about 4.3%,6.9%, and 8.7% for 5% lpg,8% lpg, and 10% lpg, respectively, which reduces the tendency of knocking as well as regulates combustion pressure and hence, improves combustion. this is also confirmed with the other side of this figure where inducting lpg reduces the combustion duration clearly, by 8.9%, 10%, and 9.4% for 5% lpg,8% lpg, and 10% lpg, respectively. figure 7. illustrates the variation in ignition delay and combustion duration 7.2 the performance analysis. to properly understand the influence of lpg on engine performance, we measured the brake-specific fuel consumption (bsfc) and brake thermal efficiency (bte) at full load and a constant engine speed of 1500 rpm. the effect of lpg on bte and bsfc is shown in figure 8. it stands to reason that when lpg is used with diesel, more fuel will be used overall, resulting in higher brake-specific fuel consumption (bsfc) of about 0.14%, 0.26%, and 0.4% at 5%,8%,10% of lpg, respectively and lower brake thermal efficiency according to the direct relationship between them occurred at 10% lpg. the current result is also found in the results of figure 8. the effect of lpg on bsfc and bte figure 9 shows that the mechanical efficiency and volumetric efficiency of the engine are significantly affected by the lpg content. the engine's volumetric efficiency, which was 92.59% while running on diesel fuel but maysaa j. mohsen and mohamed f. al-dawody /al-qadisiyah journal for engineering sciences15 (2022) 147–164 163 0 1 2 3 4 5 6 7 8 9 10 lpg (%) 2500 2750 3000 3250 3500 3750 4000 n o x ( p p m ) 0.0 0.5 1.0 1.5 2.0 2.5 b s n full load 15.5 cr, 1500 rppm nox bsn dropped to 92.53% when using lpg, and the mechanical efficiency of the engine dropped as the lpg concentration rose. this percentage drops from 83.18 when there is no lpg present to 82.9 when there is 10% lpg present. reasons for this might include an unfavorable combustion environment and/or incomplete combustion. figure 9: variation in mechanical and volumetric efficiency 7.3 the emission analysis since most emissions occur at full load, this is the case we concentrate on to determine which blends have the most value. in figure 10, we see the nox concentration and bsn verse lpg percentage. a slight increase was noticed in nox, only at higher lpg concentrations; at 10% lpg, the nox increase is roughly 0.83 %. considerable reduction in the bsn was observed in the case of using lpg along with diesel because lpg has a lower c/h ratio hence it emits less smoke compared to neat diesel. as the engine ran with 5%, 8%, and 10% lpg the bsn is reduced by 3%, 6.74%, and 9.83% respectively compared to the case of 0% lpg (diesel alone). figure 10. depicts the variation in smoke and nox emissions 8. conclusions following are the results of the simulation analysis: 1. no considerable increase in cylinder pressure when lpg is added, for example, the maximum increase is 0.4% while using 10% lpg. 2. compared to pure diesel, the rate of heat release at a crank angle of 365 degrees has dropped a little. diesel fuel is around 32.53 (1/deg) and 10% lpg is approximately 30.28 (1/deg). 3. ignition delay was reduced by 8.7%, 7%, and 4.3% when used 10% lpg, 8% lpg, and 5% lpg respectively. 4. insignificant changes in bte and bsfc are noticed while adding lpg to diesel. 5. the mechanical efficiency and volumetric efficiency of the engine both decrease a bit with increasing the percentage of lpg. 6. it is possible to notice a slight increase in nox when lpg is used along with diesel 7. measurable decrease in bsn by 3%, 6.74%, and 9.83% for 5%, 8%, and 10% lpg respectively compared to the case of 0% lpg (diesel alone) references [1] aydin, m., irgin, a. and çelik, m.b., 2018. the impact of diesel/lpg dual fuel on performance and emissions in a single cylinder diesel generator. applied sciences, 8(5), p.825. 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[45] al‐dawody, m.f., idan al‐chlaihawi, k.k. and al‐farhany, k.a., 2022. numerical simulation of the effect of lpg blending on the characteristics of a diesel engine. heat transfer. article al-qadisiyah journal for engineering sciences 15 (2022) 001–008 contents lists available at http://qu.edu.iq al-qadisiyah journal for engineering sciences journal homepage: http://qu.edu.iq/journaleng/index.php/jqes * corresponding author. e-mail address: tonyagyemang@yahoo.com (anthony agyei-agyemang) https://doi.org/10.30772/qjes.v15i1.802 2411-7773/© 2021 university of al-qadisiyah. all rights reserved. this work is licensed under a creative commons attribution 4.0 international license. effects of roof angle, inlet gap size and drying time on dryer mass flow rate and moisture content in a chimney-dependent solar crop dryer using design of experiments (doe) anthony agyei-agyemanga*, peter oppong tawiaha, john k. afriyieb and michael k. commehc adepartment of mechanical engineering, college of engineering, kwame nkrumah university of science and technology, kumasi, kum asi, ghana. bdepartment of mechanical engineering, kumasi technical university, kumasi, +233, gh ana. ctechnology consultancy centre, college of engineering, kwame nkrumah university of science and technology, kumasi, +233, ghan a. a r t i c l e i n f o article history: received 09 february 2022 received in revised form 6 march 2022 accepted 15 may 2022 keywords: solar dryer roof angle inlet gap size multilevel factorial design moisture content ghana a b s t r a c t a chimney dependent solar crop dryer (cdscd) was designed and developed. design of experiments (doe) was used to carry out experiments using a statistical three level non randomized factorial experimental design in minitab statistical software version 19.0. the effect of three drying parameters, roof angle (º), inlet gap size (mm), and time (h) on dryer inlet mass flow rate (kg/s) and moisture content (%) were studied. the regression results showed that there was a satisfactory fit of the model variability for both dryer inlet mass flow rate and crop moisture content. the p-value for each parameter was less than 0.005, which is statistically significant. the r-squared (r2) value was 94.67% for inlet air mass flow rate study and 99.72% for moisture content. it was observed that the optimal values for achieving a low moisture content response (≤ 24%) were roof angle of 81º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 24 hours while the optimal values for achieving high inlet air mass flow rate (≥ 0.357 kg/s) were roof angle of 51º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 5 hours. the findings could be implemented and utilized for achieving optimum ventilation and drying performances to refine dryer (cdscd) design. © 2022 university of al-qadisiyah. all rights reserved. 1. introduction mofa [1] observed that although agriculture is the largest sector of the economy in ghana, contributing about 39% of gdp, it is still confronted with high post-harvest losses as a result of poor post-harvest management. for instance, zakari [2] estimates that the average postharvest loss of mango is between 20 % and 50 %. the main causes for the losses being attributed to fruit flies, diseases, poor management and storage during transit to the market. drying, if used effectively could minimize crop losses. crop drying refers to the process of removing moisture from a crop. solar dryer is a solar energy application in drying and conserving agricultural food products and other products [3]. traditionally, farmers spread their crops on mats in the open sun to dry them, therefore exposing them to environmental conditions such as rain, pest, rodents and different types of unhygienic conditions. harnessing solar energy is becoming more and more popular in drying. in solar drying, solar energy is the main source of energy used. recent studies have shown that using solar energy in preserving agricultural products like grains, fruits, and vegetables is economical and ideal for farmers in the developing countries [4]. however, the use of solar energy alone as the source of heat for drying and preservation during the rainy season, is not feasible and therefore proves difficult [5]. as a result, it calls for different ways in which the solar energy is utilized to overcome http://qu.edu.iq/ https://doi.org/10.30772/qjes.v15i1.802 http://creativecommons.org/licenses/by/4.0/ 2 anthony agyei-agyemang et. al./al-qadisiyah journal for engineering sciences 15 (2022) 001–008 the challenge. different designs for drying have been proposed and tested to solve these problems. the use of a chimney allows improved ventilation. a dryer’s chimney combined with an inclined roof, inclined at right angle in a drying chamber design, when coupled with a suitable inlet exit area ratio, was observed to increase the ventilation in direct mode dryer [6-10]. a solar dyer with a tent dryer architecture, generally works on the principle that in operation, radiant energy of short wavelength from the sun is transmitted through transparent drying chamber and chimney glazing to fall on absorbers in the dryer. the absorbers, after absorbing this radiant energy, in turn emit heat energy of long wavelength that gets trapped but does not pass through the glazing back into the atmosphere. the trapped energy heats up the air in the chamber and chimney and effectively dries the product in the drying chamber. that is, cold air flows through the dryer by entering the bottom inlet, gets heated up and dries the crops inside the drying chamber. during this process, the air absorbs moisture from the crops and flows through the solar chimney where its density drops after absorbing more heat and is then driven upwards to exit through the top vent into the surroundings, effecting a continuous flow where the cold, dense air is drawn in to displace the warm air flowing through the dryer [6-10]. it has been confirmed by other researchers that properly designed solar chimneys have been observed to improve the flow of air in an enclosed chamber [11-15]. generally, high amount of moisture in dried seeds increases incidence of insect infestation and growth of microorganisms. fast drying of agroproducts reduces their moisture content and therefore prevents conditions favourable for the growth of fungi and microorganisms that affect food quality during storage [16]. molds that produce aflatoxins (aspergillus flavus) also grow on products stored under conditions with high relative humidity and temperature [18-19]. aflatoxins can cause many different health issues and diseases like liver cancer, renal diseases, and gastroenteritis, and they could also be associated with child growth impairment [20]. the rate of insect infestation of post-harvest crops worsens with increase in relative humidity and temperature. drying could be classified generally into three: sun, mechanical, and solar drying. sun drying is the direct exposure of a product to the sun on a surface, resulting in direct heating by solar radiation and eventual removal of moisture through circulation of air, naturally. sun drying needs no additional source of energy other than sunlight and is therefore the cheapest method of drying [21]. however, this method is not efficient and is also labor and time intensive. it is not efficient because natural air flowing around the crop to be dried could introduce moisture and also remove essential heat which otherwise could enhance the drying process [22]. mechanical drying is a process in which heat is introduced artificially to increase the drying medium’s temperature to cause evaporation of excess moisture from a product. the heat source is usually either fossil fuel or electricity. major types of mechanical dryers include bin, cabinet, mixed flow, and continuous cross flow dryers. the solar dryer is the third group and the most economically sustainable option for developing countries. a solar dryer, unlike sun drying, is a customized enclosure which regulates the process of drying and shields the product against contamination with dust and rain, as well as infestation with insects [23], thereby reducing the drying time significantly, and improving the quality of dried product vis a vis that of sun drying [24]. that is, the drying temperature rises as the relative humidity falls, resulting in a reduced moisture content in dried product. solar dryers come in different forms. they may be classified as direct or indirect, based on whether the material to be dried is exposed to direct insolation or not. on the other hand, they may be classified based on the mechanism of air flow through the dryer, thus solar dryers can be either natural convection solar dryers or forced convection solar dryers [17]. air flows through such dryers due to thermally induced density gradient. in dryers using forced convection, a pressure difference, generated by a fan, forces air to flow through the drying chamber [17]. on the other hand, based on indirect or direct solar dryer classification, in the indirect solar dryer, a solar collector is used to heat the air entering the drying chamber. through convection heat is exchanged between the crop being dried and the hot air, and in the process heated air is forced to flow on the drying bed to remove moisture [21]. though there are different drying methods for food products, drying food in an indirect solar dryer is a prominent technology nowadays [25]. the direct solar dryer, is one in which a frame covered with transparent material and the sides protected with boards is used to protect the product being dried. the product to be dried and the drying chamber’s inner surfaces absorb solar radiation, and thus raise the product temperature and that of its enclosure to effect drying [26]. the direct dryers are appropriate for locations that have direct sunshine for long periods during day time [4]. mixed mode solar dryers integrate characteristics of both direct and indirect solar dryers [21]. heat needed to dry the produce is partly supplied by the solar collector which pre-heats the air and by direct solar insolation on the produce [26]. lingayat et al. [27] reports that the indirect mode dryer could be more effective and efficient than the direct mode dryer. another category of solar drying is the hybrid solar dryer. hybrid solar dryers go a step further to make the dryer operational even during cloudy periods. in addition to using solar energy, hybrid systems incorporate other means of heating the air for drying a produce. all solar dryers have a means to let out exhaust air. most solar dryers let out exhaust air which collected moisture from the produce to be dried through a chimney. the air passes through the drying chamber and then flows out through the chimney due to the buoyancy effect or stack effect [28]. nasution et. al. [29] and abedini et al. [30], studied deep bed drying performance on paddy and shrimp respectively, using hybrid infrared-solar dryer and found it to be more effective than solar dryer only. using an organic paraffin wax, with a melting point of 60 ℃ as phase change material (pcm) in a solar dryer chamber with black stones as the base, radhakrishnan et al., [31] dried coconut from an initial moisture content of 55.5% to a final moisture content of about 9%, observing that the drying time of coconut decreased by about 28 and 52 h on using 100 g and 200 g of pcm, respectively, compared to open sun drying; the sensory characteristics like colour, taste, flavour, quality, and texture of the dried coconut sample were superior to the sun-dried coconut sample. senthil et al., [32] also found the integration of pmc in the solar dryer to enhance drying and reduced drying time up to 60% over a solar dryer without pcm. afriyie [6] observed from trials on a cdscd that even though open sun drying could proceed very well at the initial phases of drying, the cdscd always finishes the drying process faster. therefore, improving on direct solar dryer is good and worth exploring. afriyie [6] cautioned that, relying on one particular feature of the cdscd for performance improvement may render the dryer uneconomical or unstable, and recommended that a reasonable moderate change in two or more features, or design characteristics, could be the best method of improvement of a cdscd. design of experiments (doe) is a good method of studying the combined effects of two or more features on a system and was therefore used for this study. design of experiments (doe) is a statistical method that allows the variation of different factors and combination of factors at the same time to study a system for optimum values [33]. design of experiment (doe) has so many advantages over traditional anthony agyei-agyemang et al./al-qadisiyah journal for engineering sciences 15 (2022) 001–008 3 experimental methods where most of the time one parameter is studied at a time and then through try-and-error modifications are made in new experiments to improve a system. some of the advantages of doe include the ease of its use in the evaluation, comparison and optimization of design configurations, evaluation of possible material alternatives, selection of design parameters and configurations for robust products that can work under different field and environmental conditions [34]. ultimately, doe allows one to make more informed decisions during the problem-solving process, and conclude with better solutions within a shorter time [33]. the main disadvantages of doe are that it requires a lot of skills, strong knowledge of statistical methods, discipline and effective communication between members of a project team for it to work reliably [33]. it can therefore be concluded that doe improves process yields, reduces variability, promote closer conformance to nominal or target requirements and specifications, reduces development time, and reduces overall costs [34]. therefore doe was selected as the method for this study. 2. materials and methods 2.1. experimental works a laboratory scale model for the cdscd with three (3) substitutable roofs (each with diverse roof angles oriented to the vertical plane) was fabricated. the roof angles were oriented at 51°, 64° and 81°. lexan sheet was used as glazing material for the drying chamber walls. the drying chamber width positioned normal to air flow was 440 mm and the length in air flow direction was 530 mm. 40 mm thick wood was used as the base of the dryer with the topmost surface of the wood painted black to function as a heat absorber of the dryer. three plates of lexan sheet with a length covering the dryer’s width were placed at the inlet to set inlet gaps at 30, 50 and 70 mm during the experiment. a steel grate with a width of 400 mm and a length of 370 mm was placed 150 mm above the base of the dryer to serve as a drying shelf. two extra meshes, each with about half the length of the first mesh, were also used for different shelf configurations during the drying process. the chimney had a rectangular cross-section (400 mm width, uniform gap of 80 mm and a height of 625 mm). the dryer exit was oriented at right angles to the chimney cross-section at the top and had an exit gap which was 30 mm, and a width of 335 mm but curved at the ends at a radius of 15 mm. lexan sheet glazing material was used as the walls of the chimney. figure 1. functional architecture of cdscd. a removable back wall of wood constructions with an internal black painted surface was used as chimney absorber. solar irradiation was simulated by setting up eight 100 w infrared lamps in front of the dryer. thermocouple probes, handheld anemometer and handheld thermohygrometer were used to record temperature, relative humidity and air velocities within and outside the drying chamber. details of instrumentation setup can be found in afriyie [6] and afriyie et al. [7]. figures 1 and 2 present a sketch of the functional architecture and pictorial view of the laboratory setup for the cdscd. of the dryer tray arrangements and the pictorial view of the field setup respectively. figure 2. picture of the laboratory setup of cdscd. 4 anthony agyei-agyemang et. al./al-qadisiyah journal for engineering sciences 15 (2022) 001–008 2.2. design of experiments design of experiments (doe) was used. the designed drying experiments were carried out using statistical three level non randomized factorial experimental design which was implemented in minitab statistical software version 19.0. five drying parameters were considered in this experiment namely: roof angle (º), inlet gap size (mm), drying time (cm), dryer inlet mass flow rate (kg/s) and moisture content (%). the dryer inlet mass flow rate effects had a total of 216 runs, and the moisture content effects had 225 runs. presented in table 1 is the design summary for the inlet mass flow rate, and moisture content effects experiments. table 2 gives the experimental design summary for the effects of roof angle, inlet gap size and time on both inlet mass flow rate, and moisture content. from table 2, the experiments consist of three factors: roof angle and inlet gap size with three levels each, and time with 24 levels. table 1. design summary for the inlet mass flow rate and moisture content effects experiments. design summary inlet mass flow rate effects study moisture content effects study factors: 3 replicates: 1 factors: 3 replicates: 1 base runs: 216 total runs: 216 base runs: 225 total runs: 225 base blocks: 1 total blocks: 1 base blocks: 1 total blocks: 1 table 2. the experimental matrix for effects of roof angle, inlet gap size and time on inlet mass flow rate, and moisture content. factor level values 1st 2nd 3rd 4th 5th 6th 7th … 23rd roof angle (°) 51 64 81 inlet gap, (mm) 30 50 70 time (h) 1, 2, 3, 4, 5, 6, 7, 8,9,10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 3. results and discussions the effects of roof angle, inlet gap size and time on dryer inlet mass flow rate is presented in section 3.1 while the effects of roof angle, inlet gap size and time on dryer moisture content is discussed in section 3.2. 3.1. effects of roof angle, inlet gap size and time of dryer on inlet air mass flow rate the pareto chart of standardized effects for mass flow rate response with the confidence level set at 0.05 is shown in figure 3. from figure 3, time (a), inlet gap (b), roof angle (c), interaction of time and inlet gap (ab), interaction of time and roof angle (ac), and interaction of inlet gap and roof angle (bc) have 7.6, 7.4, 5.8, 3.3, 0.4 and 0.6 standardized effect values respectively. the pareto chart shows that time has the highest standardized effect (7.6) on the dryer inlet mass flow rate while ac (time and roof angle) has the least standardized effect of 0.4. aside the individual factors (a, b and c), interaction of time and inlet gap (ab) also has a significant effect on the dryer inlet air mass flow rate. figure 3. pareto chart of standardized effects (inlet mass flow rate response). the p-values, which are good metrics to evaluate a statistical model, were calculated and presented together with the f-values, degrees of freedom and the mean-squares in table 3. the p-value for each term (roof angle, inlet gap, and time) was less than 0.005 which is statistically significant. figure 4 presents residual plots for inlet mass flow rate. from the residual plots, the pattern for normal probability plot is an s-curve which indicates a distribution with long tails. the residuals versus fits plot confirms the assumption that the residuals are randomly distributed and have a nonconstant variance with uneven spreading of residuals across fitted values as points are random on both sides of the zero-line (0) with no patterns in the point positions. histogram plot pattern depicts long tails in both (right and left) directions which indicates a general skewness in the model. some few bars lie far away on the left and right sides which indicates an outlier pattern. the residuals in residuals versus order plot appear randomly, close to the centre line, giving a pattern that shows independent residuals. the residual plots for air inlet mass flow rate show that the result is satisfactory. table 3. the analysis of variance results for effects of roof angle, inlet gap size and time on inlet mass flow rate. source df adj ss adj ms f-value p-value model 123 0.000648 0.000005 13.28 0.000 linear 27 0.000593 0.000022 55.37 0.000 roof angle (deg) 23 0.000553 0.000024 60.57 0.000 inlet gap (mm) 2 0.000025 0.000012 31.44 0.000 time (h) 2 0.000015 0.000008 19.46 0.000 2-way interactions 96 0.000055 0.000001 1.44 0.039 roof angle (deg)*inlet gap (mm) 46 0.000038 0.000001 2.06 0.002 roof angle (deg)*time (h) 46 0.000016 0.000000 0.87 0.688 inlet gap (mm)*time (h) 4 0.000001 0.000000 0.83 0.510 error 92 0.000037 0.000000 total 215 0.000685 anthony agyei-agyemang et al./al-qadisiyah journal for engineering sciences 15 (2022) 001–008 5 degrees of freedom (df), sum of squares (ss), mean squares (ms)(variance), ratio of variance of a source to variance of error (f), significance of a factor at 95% confidence level (p < 0.05). figure 4. residual plots for inlet mass flow rate. a summary of computed regression values is presented in table 4. rsquared (r2) which represents a goodness of fit measure for linear regressions was 94.67%. the adjusted values of r-squared (r-sq(adj)) and predicted values of r-squared (r-sq(pred)) were 87.54% and 70.61% respectively. these regression results show a satisfactory fit of the model variability for the dryer inlet mass flow rate. table 3. the analysis of variance results for effects of roof angle, inlet gap size and time on inlet mass flow rate summary model s r-sq r-sq(adj) r-sq(pred) 0.0006300 94.67% 87.54% 70.61% the main effect plot for inlet mass flow rate is shown in figure 5. from figure 5, a roof angle of 51º shows the highest mean mass flow rate at inlet to be 0.00495 kg/s; whilst the other roof angles show lower effects on mean inlet mass flow rate (roof angles of 64º and 81º yielded 0.00461 kg/s and 0.004296 kg/s respectfully). the inlet gap of 30 mm influenced a mean inlet mass flow rate effect of 0.00414 kg/s. the inlet gaps of 50 mm and 70 mm attained mean inlet mass flow rate of 0.00480961 kg/s and 0.0049035 kg/s respectively. time of drying which plays a significant role in any drying process yielded higher mean mass flow rate at the inlet of 0.0.0053482 kg/s at 5 hours into the drying, 0.00541763 kg/s at 14 hours into the drying and 0.00553361 kg/s at the end of the drying process at 24 hours. the interaction plot for mass flow rate at inlet, showing the various mean inlet mass flow rates and the interaction between various drying factors (roof angle, inlet gap and drying time), is shown in figure 6. the highest mean of inlet mass flow rate for the interaction between roof angle and inlet gap is 0.00534223 kg/s. from figure 6, the roof angle and time interaction show the highest mean inlet mass flow 0.00593005 kg/s at 19 hours drying time. the following drying time periods (hours) for the 51 º roof angle attained high mean inlet mass flow rates above 0.00534223 kg/s: they are 15, 16, 17, 18, 19, 20, 21 22, 23 and 24 hours. figure 5. main effects plot for inlet mass flow rate. figure 6. interaction plot for inlet mass flow rate. a response optimization was carried out to select the optimum factor values necessary to achieve high inlet mass flow rate to accelerate drying. figure 7 presents the optimization plot after carrying out response optimization. the optimal values for achieving very high inlet mass flow rate response (≥ 0.0069 kg/s) are roof angle of 51º, inlet gap of 30 mm and a minimum drying time of five hours. figure 7. optimization plot. 3.1. effects of roof angle, inlet gap size and time on moisture content figure 8 presents the pareto chart of standardized effects for moisture content response at a confidence level of 95%. roof angle (a), interaction of roof angle and inlet gap (ab), inlet gap (b) and time (c) had the same standardized effect of 7.6. roof angle and time interaction (ac), and inlet 6 anthony agyei-agyemang et. al./al-qadisiyah journal for engineering sciences 15 (2022) 001–008 gap and time interaction (bc) had 0.6 and 0.1 standardized effects respectfully, which are below the reference line (1.985), and are therefore not significant. table 4 shows analysis of variance results for effects of roof angle, inlet gap size and time on moisture content. the p-value for each term (roof angle, inlet gap and time) was less than 0.005, which is statistically significant. figure 8. pareto chart of standardized effects (moisture content response) table 4. the analysis of variance results for effects of roof angle, inlet gap size and time on inlet mass flow rate. the models fitted the data well. a summary of computed regression values is presented in table 5. the r-squared (r2) which represents a goodness of fit measure for linear regressions was 99.72%. the derived adjusted rsquared values (r-sq(adj)) and predicted r-squared values (r-sq(pred)) were 99.35% and 98.48% respectfully. these regression results show a satisfactory fit of the model variability for the crop moisture content. table 5. regression model summary model s r-sq r-sq(adj) r-sq(pred) 4.10506 99.72% 99.35% 98.48% presented in figure 9 are residual plots for moisture content. the pattern for normal probability plot shows a few points lying away from the line which implies a distribution with outliers. the residuals versus fits plot verifies the assumption that residuals are randomly distributed and have a nonconstant variance with fanning or uneven spreading of residuals across fitted values as the points randomly appear on both sides of the zero line (0) with no recognizable patterns in the points. the histogram plot pattern depicts long tails on both (right and left) directions which indicate a general skewness in the model. the residuals in the residuals versus order plot are distributed randomly around the centre line and the pattern formed indicate that the residuals are independent. in summary the residual plot results show a good model fit. figure 9. residual plots for moisture content. the main effects plot for moisture content is shown in figure 10. the highest mean value of moisture content for roof angle effect was 119% at a roof angle of 51º. roof angle of 64º and 81º recorded mean moisture content of 113.5% and 108% respectfully. for inlet gap effect, the lowest mean moisture content measured was 108% at inlet gap of 30 mm. the highest mean moisture content was 117% at inlet gap of 70 mm and the next was mean moisture content of 115% at 50 mm inlet gap. for effect of temperature, the highest mean moisture content drop was from 202 % to 24%, and it occurred after 24 hours. this shows the time dependency nature of a typical drying process. figure 11 presents interaction plot for moisture content. the lowest mean moisture content response recorded for interaction of roof angle and inlet gap was 90% at 81º and 30 mm; whilst the highest was 140% at 64º roof angle and 50 mm inlet gap. the next mean moisture content recorded was 135%, at 64º and 70 mm. results from figure 11 show that interaction between roof angle and time and interaction between inlet gap and time were heavily influenced by the time factor; the lowest recorded was after 24 hours for both as 24% at roof angle of 81º and inlet gap of 30 mm. source df adj ss adj ms f-value p-value model 128 582889 4553.8 270.23 0.000 linear 28 576961 20605.8 1222.79 0.000 roof angle (deg) 2 3808 1903.8 112.97 0.000 inlet gap (mm) 2 2712 1355.9 80.46 0.000 time (h) 24 570442 23768.4 1410.46 0.000 2-way interactions 100 5927 59.3 3.52 0.000 roof angle (deg)*inlet gap (mm) 4 4660 1165.1 69.14 0.000 roof angle (deg)*time (h) 48 758 15.8 0.94 0.591 inlet gap (mm)* time (h) 48 509 10.6 0.63 0.961 error 96 1618 16.9 total 224 584506 anthony agyei-agyemang et al./al-qadisiyah journal for engineering sciences 15 (2022) 001–008 7 figure 10. main effects plot for moisture content. figure 11. interaction plot for moisture content. the results of optimization response prediction presented in figure 12 shows the optimal values which will improve drying efficiency. the optimal values for achieving low moisture content response (≤ 24%) are roof angle of 81º, inlet gap of 30 mm and a minimum drying time of 24 hours. the 30 mm inlet gap implies an inlet area of 0.03 m × 0.39 m or 0.0117 m2 inlet cross-sectional area. with exit cross-sectional area of 0.03 m × 0.335 m with two (2) semi circles with 15 mm radius on either side of the exit, giving a cross-sectional area of 0.0107568 m2. thus, the optimum inlet to outlet area ratio is 1.08768:1. figure 12. optimization plot for moisture content. 4. conclusions from the study on effects of roof angle, inlet gap size and time on moisture content it can be concluded that the optimal values for achieving low moisture content response (≤ 24%) are such that for a given ambient relative humidity, a roof angle of 81º, an inlet gap such that the inlet to outlet area ratio is 1.08768:1 and minimum drying time of 24 hours. on the other hand, from the study of effects of roof angle, inlet gap size and time on dryer inlet air mass flow rate, the optimal values for achieving high inlet air mass flow rate (≥ 0.0069 kg/s) are such that for a given ambient relative humidity, a roof angle of 51º, an inlet gap which gives inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of five hours. that is, for good drying conditions for a given ambient relative humidity is such that, an inlet gap which gives an inlet to outlet cross-sectional area ratio of 1.08768:1, drying time of at least 24 hours, and roof angle of either 51º 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(2020). design and analysis of experiments (8th ed.). wiley. https://doi.org/10.5402/2012/194359 https://doi.org/10.14311/tpfm.2022.005 https://doi.org/10.1016/j.energy.2022.123704 https://doi.org/10.1016/j.renene.2021.10.081 https://doi.org/10.1007/978-981-33-6831-6_10 https://doi.org/10.1007/978-981-33-6831-6_1 https://doi.org/10.1016/b978-0-12-802296-2.00006-8 https://doi.org/10.3390/toxins14020115 https://doi.org/10.1098/rsif.2011.0482 https://doi.org/10.1146/annurev-food-030713-092431 https://doi.org/10.1016/j.apenergy.2019.114005 https://doi.org/10.1016/j.rser.2011.07.134 https://doi.org/10.1016/j.apenergy.2019.114005 https://doi.org/10.1016/j.seta.2021.101466 https://doi.org/10.1088/1755-1315/951/1/012101 https://doi.org/10.1088/1755-1315/951/1/012101 https://doi.org/10.1016/j.solener.2022.01.045 https://doi.org/10.1007/s11356-021-18052-7 https://doi.org/10.1007/978-981-15-9678-0_31 https://www.qualitydigest.com/inside/quality-insider-article/understanding-design-experiments-031215.html https://www.qualitydigest.com/inside/quality-insider-article/understanding-design-experiments-031215.html ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٣ في العراقعلى التربة والبيئة الكيمياوية األسمدةاثر صناعة غازي مالح مطر. د. م.أ المستنصرية الجامعة/كلية الهندسة الخالصة بعد ستينات. التاسع عشر القرن نتصفالكيماوية وتستعمل بشكل واسع عالميا منذ م األسمدةتصنع عدد من تاخذوالرتفاع اسعار االسمدة الكيماوية المستوردة وكنتيجة لزيادة الطلب على الغذاء القرن الماضي ضوضاء المولدات ضوضاء المركبات ضوضاء المدارس ضوضاء ساحات اللعب ضوضاء الك�ب السائبة ضوضاء ا�سواق الشعبية .والكوفة سم توضيحي يبين نسب مصادر الضوضاء في أحياء مدينتي النجفر ) ٣(شكل ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٤ على حساب نوعية لكن ةومنها العراق، تحذو حذو الدول المتقدمة بتصنيع واستهالك االسمد، الدول النامية في العراق وبغض النظر عما تؤول اليه مشاكل التصنيع والتداول .أحيانا المنتج الزراعي والصحة والبيئة واء اال ان كميات التصنيع واالستعمال غير المبرمج وتأثير ذلك على عناصر البيئة المتمثلة بالتربة والماء واله خاصة بعد حرب الكويت والحصار الذي فرض طبعا، وعلى حساب البيئة ،واالستهالك قد ازدادت بدرجة كبيرة .١٩٩١على العراق عام االسمدة ستخدامار الناتجة من صناعة وسوء اثاجري هذا البحث لتسليط الضوء على مجمل اال .المية وربطها بالواقع العراقي استنادا الى التراكيز المسموح بها بيئياالكيمياوية من خالل بعض التجارب الع وحدات المعالجة وضعف نستنتج من هذا البحث ان في العراق توجد هناك سوء ادارة في التصنيع بما يتعلق ب جمل فعلى سبيل المثال ان م. سوء االستخدام وهناك مخاطر بيئية يمكن ان تستفحل بالمستقبل القريبكذلك جديةقد تحتاج الى وقفة محافظة االنبار/ الفعاليات االنتاجية في الشركة العامة لصناعة الفوسفات في القائم كويت عام ال حرببسبب أو تعطلها طرح الفضالت وعدم كفاءة وحدات المعالجة الجارية فيها بسبب اإلهمال في ار اقتصادي وصعوبة ادامة وحدات من منشات الشركة وماتبعها من حص% ٩٠٧٠ان تدمير . ١٩٩١ والملوثات ) كالفوسفوجبسم واالطيان القاعدية( المعالجة ادى الى طرح االف االطنان من الملوثات الصلبة ومن مالحظة ). الناتجة بسبب عدم وجود المرشحات في الوحدات الخاصة بانتاج حامض الكبريتيك(الغازية ٩.٤ى النهرنجد ان تراكيز الهيدروجين والفوسفور والفلور والكبريتات هي مواصفات المياه المعالجة التي تطرح ال لتر على التوالي وهي اعلى من محددات منظمة الصحة العالمية /ملغم ٧٥٠لتر و /ملغم ٥لتر و /ملغم ٥و ).لتر على التوالي/ملغم ٤٠٠-٢٠٠لتر و /ملغم ١.٥-١لتر و/ملغم ٣و اقل من ٩.٢-٦.٥(لمياه الشرب :رئيسيةكلمات .حرب الكويت، البيئة، تلوث التربة، محافظة االنبار، صناعة األسمدة، العراق the impact of chemical fertilizers industry on soil and the environment in iraq assist. prof. dr. ghazi m. mutter/college of engineering/ al-mustansiria university abstract the world mineral fertilizer industry and use are started widely in the middle of the 19th century. in the 1960s and after the increase of food demands and because of the high prices of these chemicals, many developing countries, and iraq as well, have also started to produce and use these chemicals but unfortunately on the value of food quality, health and the environment sometimes. in iraq and regardless of the problems of the random production, handling and use and their impact on the environment, these activities are become worse especially after the kuwait war and the economic embargo imposed on iraq in 1991. this research was initiated to focus on the impact of chemical fertilizers industry and use on the world and then on the iraqi environment according to the international experience in this field and to the acceptable levels of these chemicals. the salient conclusion of this work reveals that in iraq there is industrial treatment mismanagement as well as farmer misuse, hence there are ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٥ environmental problems and may be worsen in the near future. for instance, the activities of the state company of phosphate production in al-anbar province causes a noticeable pollution related to the miss management of waste disposal and due to the un efficient treatment units paralyzed because of either the 1991 kuwait war (where 70-90% of the company is being destroyed) or because the embargo and hence the difficulties in maintaining the treatment units. in addition to the accumulation of thousands of ton of solid wastes ( as phosphogypsum and alkali clays ) and the gaseous pollutants of the sulfuric acid production units, it could be noted that the properties of treated liquid effluents ( like ph, p2o5, f and so4 are 9.4, 5ppm, 5ppm and 750ppm , respectively) which are greater than the who standards of drinking water ( 6.5-9.2, less than 3ppm, 1-1.5ppm and 200-400ppm, respectively ). المقدمة الحاجــة المتزايــده للغــذاء اســتخداما واســعا لالســمدة الكيمياويــة باعتبارهــا المصــدر تتطلــب الزراعــة الكثيفــة وتلبيــة الفســفور و البوتاســيوم فــي التربــة وهــذا يســتدعي تنــامي وتيــرة صــناعة االســمدة الكيمياويــة الرئيســي للنــايتروجين و دراســـات منظمـــة االمـــم المتحـــده لالغذيـــة و الزراعـــة الـــى ان االنتـــاج أشـــارتفقـــد . الطلـــب العـــالمي عليهـــا وازديـــاد دة الكيمياويـة بمعـدل علـى االسـم وان الطلـب حينهـا سـيزداد% ٧٥بنسـبة ) ٢٠٣٠ -١٩٩٥(الزراعي سيزداد للفترة ifaاستنادا الى المنظمة العالمية لصناعة االسـمدة). ٢٠٠٥االسكوا ( ٢٠٣٠سنويا حتى عام %١.٣متوسطه قليــه بــدا اعتبــار اضــافة االســمدة الكيميائيــه كاحــد العمليــات الح) (unep 1998 وبرنــامج االمــم المتحــدة للبيئــة عشـر وازدادت كميـة اسـتعمالها بعـد تاسعي منتصف الى اواخر القرن الفي اوربا فال و ا المهمه في االنتاج النباتي مـــن االســـتهالك العـــالمي لالســـمدة يـــتم فـــي الـــدول %٨٧ان ١٩٦٠وقـــد قـــدر فـــي عـــام. الحـــرب العالميـــة الثانيـــة اخــذ ١٩٩٠-١٩٨٠وفــي الفتــره .المتقدمــه امــا فــي الــدول الناميــه ومنهــا العــراق فقــد زاد اســتعمالها بعــد الســتينات الســتهالك بــالثبوت عالميــا كنتيجــة الســتقرار تعــداد ســكان العــالم وكــذلك لتحســن االدارة الحقليــة و الوصــول الــى ا بدات الزيادة في ١٩٩٠بعد عام . وكذلك العودة الى استخدام االسمدة العضوية االنتاج االمثل لكل وحده سمادية بـــــالبروز وقـــــدرت الكميـــــات المســـــتعمله فيهـــــا صـــــناعة و اســـــتعمال االســـــمدة الكيمياويـــــة مـــــن قبـــــل الـــــدول الناميـــــه ان بعـض هـذه علما .١٩٦٠ في عامفقط %١٣من مجموع االستهالك العالمي بعدما كانت تمثل %٦٠بحوالي الزيادات في التصنيع و االستعمال قد تكون غير اقتصادية كنتيجة لقلة الـوعي و سـوء االسـتعمال الـذي ادى الـى المرئيــه علــى المــدى القريــب و التــي بــدات تشــغل بــال المختصــين فــي الوقــت بــروز بعــض المخــاطر البيئيــه غيــر الكيمياويــة علــى البيئــه باتجــاهين اولهمــا يقــع ضــمن مــا ينــتج مــن ملوثــات خــالل األســمدة ةتــؤثر صــناع. الحاضــر لخــاص ففــي اجتمــاع كيوتــو ا .الــى البيئــة بعــد االســتعمال و هــذه الكيمياويــات اثنــاء تســربالتصــنيع والثــاني نتيجــة تــم االتفـاق بــين الـدول الصــناعية لتقليـل الغــازات الخاصـة باالحتبــاس الحـراري بنســبة ١٩٩٧بالمنـاخ المنعقــد عـام والغــازات التــي يجــب ان تقلــل ينــتج معضــمها مــن .٢٠١٢٢٠٠٨ بــينللفتــرة ١٩٩٠عمــا كــان ينــتج عــام %٥ فعلــى ســبيل المثــال يعتبــر .ch4 وكــذلك غــاز الميثــان co2, no2, n2oهــي و صــناعة االســمدة الكيمياويــة co2 كنــاتج عرضــي غيــر مرغــوب فيــه فــي صــناعة االمونيــا بينمــا يــتم اطــالقno2 حــامض إنتــاجعمليــة أثنــاء ).kong shang) 1998النتريك لغرض انتاج سماد نترات االمونيوم الكيمياويـــةالبيئيـــة الناتجـــة عـــن تصـــنيع االســـمدة ثار يهـــدف البحـــث الـــى تســـليط الضـــوء علـــى مجمـــل اال ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٦ وبالتالي ربطها بما يجري علـى البيئـة فـي العـراق مـن خـالل متابعتنـا لصـناعة االسـمدة الفوسـفاتية عالميا وتداولها .في معامل الشركة العامة للفوسفات في القائم الكيمياوية األسمدةصناعة ( االنتــاج النبــاتي فيمــا يلــي عرضــا لالنــواع الرئيســية مــن االســمدة التــي ينتشــر اســتخدامها لغــرض زيــادة ).٢٠٠٥االسكوا االسمدة النايتروجينية -ا تعتبــر االمونيــا المكــون الرئيســي لهــذه االســمدة وتتكــون نتيجــة تفاعــل النــايتروجين المســتخرج مــن الهــواء .الجــوي مــع الهيــدروجين المســتخرج مــن المــواد الهيدروكاربونيــة كــالفحم و الــنفط الخــام و الغــاز الطبيعــي و المــاء عتبــر الغــاز الطبيعــي الخيــار االفضــل اقتصــاديا و بيئيــا للحصــول علــى المــادة االوليــة الالزمــة لصــناعة االمونيــا ي من النايتروجين عند مزجها مع % ٨٢ تساهم االمونيا التي تحتوي على نسبة .وعلى الوقود التمام عملية التفاعل .اليوريا أهمهاو مواد اخرى في تصنيع انواع متعددة من االسمدة النايترجينية الفوسفاتية األسمدة -ب حيـــث يجـــري انتـــاج هـــذه .تعتبـــر صـــخور الفوســـفات المـــادة الخـــام الرئيســـية لصـــناعة االســـمدة الفوســـفاتية االسمدة باضافة الحوامض الى صخور الفوسفات حيث عند اضافة حامض الكبرتيك ينتج سماد السوبر فوسـفات بينمــا ينــتج ســماد الســوبر فوســفات .ن خــامس اوكســيد الفســفورمــ% ٢١-١٦ االحــادي الــذي يحتــوي علــى نســبة mclaren(مـــن خـــامس اوكســـيد الفســـفور عنـــد اضـــافة حـــامض الفســـفوريك % ٤٨-٤٣ الثالثـــي الـــذي يحتـــوي ١٩٨٧ .( االسمدة البوتاسية -ج ه المـواد يستخرج البوتاسيوم كمادة قابلة للذوبان ممزوجا مـع جزيئـات الكبريـت او الكلـور وتجـري تنقيـة هـذ تسـتخدم المـواد المنتجـة مباشـرة كسـماد بوتاسـي او علـى . بازالة كلوريد الصوديوم منها وثم تركيزها قبـل االسـتخدام تستخدم الطاقة الكهربائية و الوقود السائل كمصادر للطاقـة فـي انتـاج هـذا . شكل كلوريدات و كبريتات البوتاسيوم وبعض دول اوربا الغربية كفرنسا و اسبانيا و ايطاليا وكذلك االردن و السماد و تعتبر كندا و روسيا و بال روسيا ) ١٩٨٣ mayrhafer، ٢٠٠٥االسكوا (فلسطين المحتلة من اهم الدول المنتجة للبوتاس الطلب العالمي على االسمدة الكيمياوية ١ ( ئيـــةمليـــون طـــن مـــن العناصـــر الغدا ١٦٨بنحــو ٢٠٠٣قــدر الطلـــب العـــالمي علـــى االســـمدة عـــام بينما قدراالنتاج العـالمي فـي ). اوكسيد البوتاسيوم% ١٤خامس اوكسيد الفسفور و% ٢١نيتروجين و% ٦٥بواقع ١٣٦مليـون طـن مـن مـادة االمونيـا و ١٣٣مليون طن مـن الموادالسـمادية الخـام بواقـع ٣٨٠العام ذاته بحوالي تســاهم البلــدان . مليــون طــن مــن الكبريــت ٦٤مليــون طــن مــن البوتــاس و ٤٦مليــون طــن مــن صــخر الفوســفات و مــن % ٧ســاهمت البلــدان العربيــة بنســبة ٢٠٠٣ففــي العــام . لألســمدةالعربيــة بنســب مختلفــة فــي االنتــاج العــالمي ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٧ مـــن % ٨مـــن البوتـــاس و % ٤مـــن انتـــاج صـــخر الفوســـفات و% ٣٢مـــن انتـــاج اليوريـــا و % ٩انتـــاج االمونيـــا و ). ٢٠٠٣االتحاد العربي لالسمدة ( الكبريت صناعة االسمدة والتلوث البيئي -٢ مليـون طـن ٣٣مليـون طـن مـن النيتـروجين و ٨٠بحـوالي ١٩٩٦في عام لألسمدةالعالمي اإلنتاجقدر مليــون طــن اســمدة مستخلصــة مــن ١٣٦مليــون طــن مــن اوكســيد البوتاســيوم اي مــا يعــادل ٢٣مــن الفوســفور و إلى األسمدةتؤدي صناعة . أمريكي مليون دوالر ٥٠ت تقدر بحوالي مليون طن من المواد االولية وبمبيعا ٣٢٥ وتشـير تقــديرات منظمــة ).١٩٩٨ isherwood( انبعـاث غــازات الـى الجــو اهمهـا اكاســيد الكربـون والنيتــروجين مـن مجمـل % ١.٢الـى ان انتـاج االسـمده قـد سـاهم بنسـبة ١٩٩٧التعاون والتنمية في الميدان االقتصـادي لعـام ) مليــون طــن مــن ثــاني اوكســيد الكربــون ســنويا ٢٨٠اي مــا يعـادل ( اث تلــك االكاســيد علــى الصــعيد العــالميانبعـ ( اضــافة الــى تســبب تلــك الصــناعة فــي انبعــاث غــازات اخــرى مثــل ثــاني اوكســيد الكبريــت واول اوكســيد الكربــون :ليوقد توزعت االنبعاثات الناجمة عن االسمدة على النحو التا ). ٢٠٠٥االسكوا .بهيئة غاز منبعث للجو) من الكمية االجمالية% ٤٨اي (في السنة co2مليون طن ١٣٣ .على شكل اكاسيد نايتروجين) من الكمية االجمالية% ٢٦اي (مكافئ no2مليون طن ٧٤ ١٢النقــي ويســتخدم co2علــى شــكل غــاز ) مــن الكميــة االجماليــة% ٢٦(فــي الســنة co2مليــون طــن ٧٥ فنية قاتيطبتالنقي المنتج من صناعة االمونيا في co2من مليون طن صناعة االسمدة النتروجينية والتلوث البيئي ١ -٢ طن لكل طن نتروجين مصنع باستخدام الغاز ٢.٧الناتجة من تصنيع االمونيا بحوالي co2تقدر كمية فحم او النفط، ويحتـاج تصـنيع اليوريـا اذا ما كان يستعمل في صناعته ال% ٢٥الطبيعي ويزداد هذا الرقم بحوالي الـى الجـو co2مـن % ٢تشارك صناعة االسمدة سنويا بـاطالق . لكل طن نتروجين co2طن من ١.٦حوالي الكليــة المطلقــة نتيجــة العمليــات co2مــن كميــات % ٧مــن مجمــل نشــاطات االنســان االخــرى التــي تبلــغ حــوالي يك المستعمل فـي انتـاج نتـرات االمونيـوم واالسـمدة النتروفوسـفاتية تطلق صناعة حامض النتر . الحيوية المختلفة فـي مشـكلة االحتبـاس الحـراري لكونـه يعتبـر مـن احــد co2الـذي يعتبـر اخطـر مــن n2oكميـات كبيـرة مـن غـاز لكـل طـن مصـنع n2oكغـم ) ١٠(الـى اكثـر مـن ) ١(بـين n2oتختلف نسـبة انطـالق . محددات طبقة االوزون مـن % ٦عالميـا كنتيجـة لصـناعة االسـمدة بحـوالي n2oوقـد قـدر مـا يطلـق مـن %). ١٠٠( من حامض النتريك n2oان اكثر . من ما تنتجه وسائط النقل% ٥٠مجموع ما تطلقه فعاليات االنسان االخرى بالمقارنة مع حوالي نسـان المتعلقـة مـن مجمـوع آثـار فعاليـات اال% ٧.٥المنطلق للجو يعود الى االرض والمياه وقدرت مسؤوليته عن فقــد يــتم . فتنــتج ايضــا مــن معامــل تصــنيع االمونيــا وحــامض النتريــك) nox(امــا اكاســيد .باالحتبــاس الحــراري وهـــذا لـــه وقـــت للبقـــاء فـــي الجـــو قـــدره اســـبوع واحـــد وبعـــدها noxللحصـــول علـــى n2oاكســـدة اوكســـيد النتريـــك ). smog(الضـبخان / مـا يولـد المطـر الحامضـي اويترسب مـع الهـواء واالمطـار او بشـكل دقـائق نتراتيـه، وهـذا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٨ لكل طن من النتروجين المصنع وفي noxكغم ) ٢ -١(المطلقة من صناعة االمونيا بحوالي noxتقدر كمية noxتعتبرعمليـة تحويـل . لكل طن مـن النتـروجين المصـنع noxكغم ) ٩ -٦(صناعة حامض النتريك بحوالي كعامل مساعد، من الطرق المهمة للتقليل من هذه الغازات وقدرت كمية االمونيا الى نتروجين، باستعمال االمونيا ان خــزن وتــداول االمونيــا ونتراتهــا والمــواد الناتجــة منهــا . مليــون طــن ســنويا ١/٢المســتعملة لهــذا الغــرض بحــوالي طـر كبيـر علـى يجب ان تؤخذ بنظـر االعتبـار الن العبـث بهـا وعـدم اتبـاع الطـرق الصـحيحة بالتعامـل معهـا لـه خ ).١٩٩٨ ifa، ١٩٩٨ isherwood( االنسان والبيئة صناعة االسمدة الفوسفاتية والتلوث البيئي ٢-٢ الناتجـة مـن عمليـات تصـنيع حـامض الفسـفوريك واالسـمدة الفوسـفاتية تؤدي انبعاثات المركبـات الفسـفورية الفحـــم والمنتجـــات النفطيـــة فـــي صـــناعة فـــي تكـــوين االمطـــار الحامضـــية والتـــي ســـبق وان بينـــا مســـؤولية اســـتعمال كما ان انتاج غازات الكبريت في صناعة االسمدة الكبريتية له دورايضا في تكوين االمطار . النتروجين فيها ايضا والـذي fluorineمـن عنصـر الفلـورين %)٥.٤-٣( تحتوي صخور الفوسفات المعدني طبيعيا على. الحامضيه التـي تلـوث الجـو لـذا يجـب ان تـزال هـذه المـواد fluoride بـات الفلورايـديطلق في المحـيط الحامضـي بعـض مرك فـأذا تـرك هـذا .مـن العمليـة )flousilicic acid(عن تصنيع الفوسفات ويمكن استغالل و بيع الحامض الناتج ان جـزء مـن الفلـورين يبقـى فـي .(liming)الحامض ولم نتخلص منه فاالجدر ان تـتم معادلتـه بأسـتعمال الكلـس الســـماد وفـــي حالـــة انتـــاج حـــامض الفســـفوريك فســـيبقى هنـــاك جـــزء مـــن هـــذا الفلـــورين فـــي فضـــالت الفوسفوجبســـم phosphogypsum طـــن مـــن ١طـــن مـــن الفوسفوجبســـم لكـــل )٥-٤(يـــتم انتـــاج .النـــاتج مـــن عمليـــة التصـــنيع ة مــن كبريتــات ان الفوسفوجبســم غيــر النقــي هــذا يتكــون بصــوره رئيســي .الفســفور المحــول الــى حــامض الفســفوريك الكالســيوم باالضــافة الــى احتوائــه علــى الفلــورين و علــى بعــض العناصــر النــادرة التــي تكــون موجــوده اساســا فــي يتحلــــل .و االلمنيــــوم radiumالصــــخور الفوســــفاتية وهــــي الــــزرنيخ النيكــــل و الكــــادميوم والرصــــاص و الراديــــوم تعمال الفوسفوجبسـم يـؤدي الـى بعـض المشـاكل البيئيـه وبالنتيجة فـان اسـ radon gasالراديوم الى غازات الرادون ان وجــود الكــاديوم بتراكيــز . المهمــه واذا مــاتم تنقيــة هــذا الســماد بشــكل جيــد فهــذا بالتاكيــد ســيزيد مــن كلفــة انتاجــه عاليه يكون تاثيره سميا على االحياء جميعهـا و تبقـى عمليـة فصـله مـن صـخور الفوسـفات مكلفـه جـدا فـي الوقـت ١٩٩٨ isherwood( تبر من محددات انتاج و استعمال هذا النوع من االسمدة في االنتاج الزراعـيالحاضروتع ،ifa.( يعتبــر الفوسفوجبســم احــد المنتجــات الثانويــة لصــناعة االســمدة الفوســفاتية ويســبب تراكمــه مشــاكل بيئيــة دة والحــد مــن تاثيرهــا البيئــي وقــد متعــددة لــذلك كــان هنــاك محــاوالت بحثيــة لدراســة امكانيــة االســتفادة مــن هــذه المــا كلنكـر إلنتاج أخرىومواد )oil shale(ركزت بعض االبحاث في تركيا على حرق مزيج منه مع السجيل الزيتي ) .٢٠٠٣ ،akmre(االسمنت وافضت هذه التجربة الى نتائج ايجابية فضالت تصنيع االسمدة و التلوث البيئي ٣-٢ مركبات الفلور والفوسفوجبسم ولقد تم التطرق و فاتية الكثير من الغبارينتج عن صناعة االسمدة الفوس بينما ينتج من صناعة االسمدة البوتاسية المستخلصة من . الى مشكلة الفوسفو جبسم المنتج وتاثيراته البيئية ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٩ اد المساعدة في تصنيع االمونيا فان بعض المو أما. االمالح المعدنية كميات كبيرة من امالح كلوريد الصوديوم الكيمياوية المستخدمة في صناعتها يجب ان تبدل كل بضعة سنين وهذه المواد تحتوي على اوكسيدات لبعض .اوتستعمل الغراض اخرى recycledالمعادن المختلفة باالضافة الى مواد كيمياويه اخرى والتي يجب ان تدور تلك المواد المعروفة بالبرايمستون اما في صناعة حامض النتريك باستعمال مصادر كبريت من غير brimstone فان الرمادcinders تحتاج بعض . منه احيانا كونه غني بالمواد المعدنية يمكن ان يستفاد sludgesة الفضالت االخرى الى طرق خاصة للتخلص منها وهذا يتضمن التخلص من حمأة الفضالت السائل وعبوات filter dustوالغبار الناتج من التصفيه scrubber wastesوحدات المعالجة والفضالت المقشوطةب األسمدةمعامل أما). ٢٠٠٥ ifa ،efma(و الحاويات الكيمياوية الفارغة filter bagsالمرشحات القديمة والتي يتم اغالقها السباب اقتصادية او بيئية او عندما تنفذ المواد االولية في بعض مواقع المناجم .فوسفات و البوتاسيوم فان المشكلة في اعادة وتنظيف وتنظيم المكان والتخلص من النفايات مهم جداالخاصة بال ان ادارة التصنيع الجيدة ليس باالنتاج الوفير فقط بل يتعداه الى عملية الخزن و النقل و التداول للمنتوج وكذلك يحة لهذه العمليات قد يقلل من التلوث الناتج الصح اإلدارة إن. التعامل مع الفضالت الناتجة من هذه العمليات من صناعة االسمدة بحيث يبقى ضمن الحدود المسموح بها وعلى الجهات المسؤولة عن البيئة مراقبة ذلك )isherwood ١٩٩٨(. البيئي طاقة صناعة االسمدة والتلوث ٤-٢ ع االسمدة بلـغ حجـم اسـتهالك ففي مجال صنا. غرض كان مصدرا مهما للتلوث أليالطاقة أنتاجيعتبر مــن االســتهالك العــالمي %١.٤٥وشــكل هــذا الــرقم .مليــون طــن مــن الــنفط ١٤١حــوالي ٢٠٠٣الطاقــة فــي عــام من مجموع الطاقة المستهلكة في %٩٢وقد استهلكت صناعة االسمدة النتروجينيه نحو .االجمالي للطاقة االوليه يتـيح اسـتخدام التقنيـات . لكـل منهمـا% ٤ وسـفاتيه و البوتاسـية نسـبةصناعة االسـمده بينمـا اسـتهلكت االسـمدة الف مـن الطلـب % ٣٧عـن في صناعة االسمدة النتروجينية خفـض متوسـط االسـتهالك النـوعي بنسـبة ال تقـل الحديثة كمـا يمكــن ان تســاهم صـناعة االســمدة الفوسـفاتية فــي توليــد الطاقـة وفقــا للتقنيـات الحديثــة عبــر .االجمـالي للطاقــة .)١٩٩٨ kong shang، ٢٠٠٥االسكوا ، ١جدول (انتاج االحماض المختلفة بعد التصنيع ما لألسمدةالبيئي األثر ٥-٢-٢ بعـد التصـنيع الكيماويـة مـا باألسـمدةسـلبيا ) المتمثلـة بالتربـة والمـاء والهـواء( عناصـر البيئـة الـثالث تتـأثر ١٩٩٨ ifa(خزن وكذلك كنتيجة لسوء االستخدام وكاالتي ء النقل والو واحينا ماقبل االستعمال الحقلي بسبب س ،efma ١٩٩٨ ،avery ٢٠٠٣مطر ، ١٩٩٧:( التربة -ا مـــا نتـــرات االمونيـــوم، علـــى زيـــادة ا النتروجينيـــة، وخاصـــة كبريتـــات االمونيـــوم ونوعـــ األســـمدة أكثـــرتعمـــل نــاطق الجافــة ومنهــا تــرب وســط فــي الم ةالمنتشــر حموضــة التربــة غيــر ان بعــض انــواع التــرب، كــالترب الكلســية ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٠ ان حامضــية التربــة .وجنــوب العــراق، يمكــن ان تتجــاوز هــذة المشــكلة طبيعيــا لكونهــا تميــل الــى التفاعــل القاعــدي ففـــي المنـــاطق االســـتوائية ). ١٩٨٤العـــاني ،(يمكـــن ان تعـــالج باضـــافة الكلـــس او الاليـــم او ســـماد الفوسفوجبســـم عمومـا . ر ويحتاج الى التعويض باستمرار بسبب سرعة غسله من التربةالرطبة تكون متلطبات اضافة الكلس اكب mutter، ١٩٨٠ وآخـــرون troeh(ان الزيـــادة باضـــافة الكلـــس عـــن الحـــد المطلـــوب يزيـــد مـــن قاعديـــة التربـــة كميـــات قليلـــة مـــن تحتـــوي فـــي الغالـــب علـــى أن األســـمدة الفوســـفاتية تزيـــد مـــن خصـــوبة التربـــة لكنهـــا). ١٩٨٩ تتكون طبيعيا في الصخور الفوسفاتية يصعب فصـلها وتنتقـل بعـد التصـنيع مـع المنتجـات الغذائيـة عناصر ضاره هذا العنصر يتراكم في بعض الترب رغم كونه عديم الفائدة للنبـات والحيـوان إن. للمستهلك ولعل اهمها الكادميوم ادميوم بواسـطة النبـات يتـاثر بعـدة أن امتصاص الكـ). ١٩٩٨ ifa(غير ان تراكيزه العاليه تعتبر سامه لكليهما عوامــل منهــا تفاعــل التربــة ونســبة الرطوبــة وصــنف النبــات وهــذه جميعــا يمكــن الســيطرة عليهــا مــن خــالل االدارة ان خطر الكادميوم الناتج من تصنيع االسمدة يكون اكثر وضوحا فـي المواقـع القريبـة مـن .الجيده للتربة والنبات ).١٩٩٧ avery، ١٩٩٨ isherwood( ن يراقب باستمراراماكن التصنيع وعليه يجب ا إما بالنسـبة للعناصـر الثقيلـة والنـادرة االخـرى فتوجـد بكميـات البـاس بهـا وتتـراكم مـع مـرور الـزمن لتصـبح بمســتويات ســامة للنبــات وضــارة للفعاليــات البيولوجيــة فــي التربــة وممكــن ان تنتقــل مــن التربــة الــى المــاء والهــواء ) .٢جدول، ٢٠٠٠الجواد عبد( بسهولة الماء-ب .هناك قلق كبير من تزايد خطـر االسـمدة الكيماويـة علـى تلـوث الميـاه السـطحية والجوفيـة علـى حـد سـواء يظهـــر ان هنـــاك قلـــق كبيـــر مـــن تزايـــد خطـــر األســـمدة ) ١٩٩٨ ifa( 1998عـــام unepتقـــارير إلـــىاســـتنادا حـد سـواء علـى الـرغم مـن قلـة المعلومـات عـن هـذا الموضـوع الكيماوية على تلوث المياه السطحية والجوفيـة علـى أن 1977فـي فرنسـا عـام unifaبينـت دراسـة لألمـم المتحـدة . وخاصة بالنسـبة لـدور األسـمدة النتروجينيـة فيـه من مجموع النتروجين المعدني المطروح سنويا للنظـام % 25األسمدة النتروجينية هي المصدر األساسي لحوالي أمـــا المصـــدر األساســـي اآلخـــر .مليـــون طـــن نتـــروجين 9.4مليـــون طـــن مـــن مجمـــوع 2.3يعـــادل البيئـــي أو مـــا 2(والمخلفــات الحيوانيــة ) مليــون طــن 3(للنتــروجين فهــو مــا تــم تثبيتــه مــن الجــو مــن قبــل النباتــات البقوليــة ســنويا الموجـود فـي الميـاه مـن مجمـوع النتـروجين% 42في مسح لمنطقة معينة في فرنسـا تبـين أيضـا أن ).مليون طن فـي تجربـة . من المصـادر الصـناعية % 9من المصادر المحلية و % 49 ،)زراعة وحيوان(كان مصدره زراعيا مــن الســماد النيتروجينــي قــد يفقــد إلــى الميــاه % 5تبــين أن حــوالي ) n15(حقليــة أســتعمل فيهــا نظيــر النتــروجين ال يشـــبه البوتاســـيوم .بســـبب الخطـــأ فـــي عمليـــة التســـميدخـــالل موســـم زراعـــي واحـــد و أن ثلثـــي هـــذا المفقـــود كـــان potash ال الفسـفور و ال النتـروجين فـي خطورتـه علـى الميـاه الطبيعيـة ولـم يثبـت لـه أي تـأثير سـلبي لحـد اآلن )syres فعلــى العكــس مــن الصــوديوم يعتبــر البوتاســيوم مهــم فــي رفــع ضــغط الــدم الــواطئ لكنــه زيــادة ). ١٩٩٧ ). ١٩٩٧ waldraw(تشــكل خطــرا علــى االشــخاص المصــابين بــبعض امــراض الكلــى امتصاصــه فــي الجســم امــا بخصــوص ميــاه الشــرب فقــد أوصــت منظمــة الصــحة العالميــة فــي منتصــف الثمانينــات بــأن ال يتجــاوز تركيــز ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠١ لتــر علــى /ملغــم ٣ولتــر \ملغــم 50فــي ميــاه الشــرب عــن )p2o5بشــكل (وال الفســفور ) no3بشــكل (النتــروجين 1991في . لتر \ملغم 50بما ال يزيد عن 1997وقد تبنت دول االتحاد األوربي حدا للنتروجين عام .التوالي تبنت هذه الدول توجيها أسمته بتوجيه النترات يتعلق بحماية المياه من خطر التلوث بالنترات الناتج عن المصادر والحيوانية الحاوية على النتروجين هـو أمـر البـد استعمال األسمدة الكيماوية وقد أوضح هذا التوجيه أن. الزراعية الســمادية ســيؤدي إلــى أخطــار منــه فــي تنشــيط اإلنتــاج الزراعــي فــي الــدول األوربيــة لكــن أي زيــادة فــي هــذه المــواد .بيئية إن التقنيات الزراعية المتبعة للحفاظ على مصادر المياه من خطر النترات معروفة وقد قامت منظمة في الدول النامية لوحظ إن .1996مثال بتوضيحها بشكل دليل عام efmaاألوربيةمصنعي األسمدة المروية النتروجين المعدني هو المصدر األساسي لتلوث المياه وخاصة في مناطق انتاج الخضرفى األراضي مصنعة أو رملية األنسجة بعدما تزداد كميات إضافتها عن الحد المقرر سواء كانت أسمدة نتروجينية كيماوية المناطق المطرية يكون تلوث المياه الجوفية بالنترات الزراعية أقل بسبب كثرة األمطار وكذلك في .أسمدة حيوانية أما في المناطق المروية فتبقى مسألة إدارة المياه من العمليات . عدم توفر األسمدة الكيماوية فيها بشكل كافي ). ١٩٩٨ efma(وث المهمة للتقليل من خطر هذا النوع من التل الهواء -ج فقـد تفقـد النتـرات . يتم فقد النيتـروجين مـن االسـمدة النتروجينيـة بـثالث اشـكال وجميعهـا تـؤدي الـى التلـوث تفقـد االمونيـا الـى . بواسطة الغسل او التطاير بينما يفقد اوكسيد النتروجين خالل عمليتي النترجـة وعكـس النترجـة على االرض السبب الرئيس لالثراء الغـدائي للبيئـات الطبيعيـة وميـاة البحـار وكـذلك الجو وتعتبرعملية سوء ادارتها يعتبــر فقــد النيتــروجين بعمليــة عكــس النترجــة مؤذيــا اذا كــان . حموضــة التربــة والبحيــرات بعــد تحولهــا الــى النتــرات مـــايعرف بتـــاثير البيـــت كـــان النـــاتج اوكســـيد النتـــروجين فهـــذا يـــؤدي الـــى إذا أمـــاناتجهـــا النهـــائي غـــاز النتـــروجين، ). ١٩٩٨ ifa(الزجاجي ونقص االوزون في طبقات الجو العليا في العراق والتلوث البيئي الكيمياوية صناعة االسمدة كـــان العـــراق ولغايـــة ســـتينات القـــرن الماضـــي يعتمـــد فـــي الغالـــب وبشـــكل محـــدود علـــى اســـتيراد االســـمدة الفـالح علـى االسـمدة العضـوية ان تـوفرت وبالتـالي يكـون االنتـاج ضـعيفا الكيماوية نظـرا الرتفـاع اسـعارها ويعتمـد وهذا دفع المختصون والمسؤولون عن القطاع الزراعي للتوجه نحو استيراد االسمدة . بالمقارنة مع الدول المجاورة لصــناعة لجنــة ت فــي وزارة اشــكلوبعــد مــا لــوحظ ارتفــاع اســعار شــراء االســمدة المســتوردة . لزيــادة االنتــاج النبــاتي بعـد . أمكـنلدراسة الموضوع ووضعت خطة لصـناعة االسـمده بانواعهـا لغـرض االسـتهالك المحلـي والتصـدير ان بــدأ العمــل بانشــاء معمــل الشــركة العامــة لالســمدة الكيماويــة فــي البصــرة بطاقــة انتاجيــة ١٩٧١الدراســة وفــي العــام ) الـف طـن ١٣٨بمقـدار (ة سـماد سـلفات االمونيـوم الف طن مـن غـاز االمونيـا المسـتخدم فـي صـناع ٥٠مقدارها ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٢ يحتــوي المعمــل كــذلك علــى وحــدة ).الــف طــن ســنويا ٥٣بمقــدار ( ســنويا والمتبقــي يســتخدم فــي صــناعة اليوريــا العــاني ( الــف طــن ســنويا ٤٠٠النتــاج حــامض الكبريتيــك ويتوقــع وصــول انتــاج اليوريــا فيــه الــى مــا يزيــد علــى ( الـف طـن سـنويا ٣٦٣بحـوالي ٢٠٠٠للفوسـفات عـام هقـدر انتـاج الشـركة العامـاما الفوسفات فقـد ) . ١٩٨٤ تستهلك صناعة االسمدة النتروجينية كميات غير قليلة من المـاء تقـدر ). ٢٠٠١في ١٧٠٣مجلة الف باء عدد نـاك متر مكعب لكل طن من االنتاج مما يستوجب معالجتها قبل تصريفها خاصة وان في العراق ه ٦٠٠بحوالي الـدين / شركتان ضخمتان النتاج االسمدة النتروجينية في العراق وهما الشركة العامة لالسمدة الشمالية فـي بيجـي ان توسـع المسـاحات ). ٢٠٠٧نجـم الـدين (محافظة البصرة / والشركة العامة لالسمدة الجنوبية في خور الزبير نيع واســـــتعمال االســـــمدة فـــــى العـــــراق بشـــــكل الزراعيـــــة وخصوصـــــا بعـــــد الحصـــــار قـــــد زاد مـــــن الحاجـــــة الـــــى تصـــــ ، ٣ جـــــدول( زيـــــادة فـــــي تلـــــوث البيئـــــة واالضـــــرار الصـــــحية االخـــــرى مســـــببا مصـــــحوبا بســـــوء فـــــي ادارتهـــــاكبير ماليـين دونـم واالسـمدة المسـتخدمة ١٠المساحة المزروعـة تقـدر بحـوالي من هذا الجدول يتبين ان). ٢٠٠٣مطر االف طـن ٣الـف طـن سـماد الـداب، ٢١ الـف طـن مركـب، ٩٥ ، الف طن يوريـا ٢٧٥ بواقع( الف طن ٤٠٠ اك تفـاوت بـين المحافظـات بمعـدل كميـات االسـمدة المضـافة بوحـدة هنـو )سوبرفوسفات ومثلها كبريتـات البوتاسـيوم فـي ممـا يـدل علـى ) دونـم علـى التـوالي /كغـم ٨٦.٩و ١٥.٤اقله في نينوى واعـاله فـي ذي قـار بمعـدل(المساحة علـى الـرغم مـن ان . دونـم/كغـم ٥٥-٣٠تخدام وعدم االلتزام بالحد المقرر للسياسة الزراعية والبـالغ عشوائية االس ينهر فيلفسفور ا الفوسفور يكون معقدات مع موادالتربة وبالتالي صعوبة غسله منها لكن نالحظ وجود كميات من .ةي للمياه والتي لها اضرار بيئيه خطير وهذا ما يزيد من ظاهرة االثراء الغذائ دجلة وشط العرب وبكميات ملموسة ، ٤جــدول (الميــاه الجوفيــة فــي جنــوب العــراق وفــي محافظــة ذي قــار علــى وجــه التحديــد تلــوث امــا بخصــوص بـــالنيتروجين وخاصـــة بتراكيـــز اعلـــى مـــن المســـموح بـــه فـــنالحظ ان الميـــاه ملوثـــة بالعناصرالســـمادية) ٢٠٠٣مطـــر .وهـذا معنـاه فقـد التربـة لمغـذيات مهمـة للنبـات ميـاة المصـب العـام لفوسفور فـيبالنسبة لمياه االبار والنيتروجين وا ولكون العراق بلدا نفطيا لذا يتم استخدام النفط ومشتقاته بشكل واسع في صناعة االسمدة الكيمياويـة فيـه وبالتـالي القريبــة مــن هــذه فــان الطاقــة المســتخدمة فــي عمليــات التصــنيع ســتكون مصــدرا مهمــا للتلــوث خاصــة فــي المنــاطق .المصانع وكما تم تناوله في متن البحث القائم -والتلوث في الشركة العامة للفوسفات األسمدةصناعة ١-٣ ويعتبــر هــذا . ١٩٨٤الفعلــي عــام ةعمــل الشــرك وبــدأ ١٩٨٣القــائم عــام-الشــركة العامــة للفوســفات أنشــأت ز بحداثـة الفـن التكنلـوجي المسـتخدم باالضـافه المجمع من اكبر مجمعات انـتج االسـمدة فـي الشـرق االوسـط ويتميـ . الى وجود منجم الفوسفات في عكاشات بالقرب منه مما يوفر ميزة نسبية في االنتاج في الشركة اإلنتاجيةالعمليات ١-١-٣ وذلـــك %) ٢٠(فـــي الشـــركة مـــن اســـتخراج صــخور فوســـفاتية مـــن مـــنجم عكاشـــات بتركيـــز األســـمدةتعتمــد صـــناعة %٢٠خــــامس اوكســــيد الفســــفورالذي ينقــــل الــــى معمــــل تركيــــز الخامــــات ليرفــــع تركيــــزه مــــن للحصــــول علــــى مــــادة :تتكون مراحل انتاج االسمدة الفوسفاتية من .)١شكل ( استعدادا لعملية انتاج االسمدة % ٣٠الى ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٣ امض مرحلــة انتــاج حــ -ثالثــا مرحلــة وحــدة تركيــز الخامــات -ثانيــا مرحلــة اســتخراج الصخورالفوســفاتية -أوال . مرحلة انتاج االسمدة -خامسا مرحلة انتاج حامض الكبرتيك -رابعا الفسفوريك واقع الملوثات وسبل المعالجة في الشركة ٢-١-٣ )٦ ،٥ لجدو( واقع الملوثات في الشركة: أوال حــدات ال يطــرح منهــا اى ملــوث الــى الخــارج بــل هنــاك و مصــممه الن تتميــز معامــل االســمدة فــي الشــركة كونهــا :وتنقسم الملوثات الى مايلي .)2شكل ( معالجة للنفايات الصناعية :وتشمل الملوثات الصلبة -١ .طن لكل طن من الحـامض المصـنع ٥وتنتج من انتاج حامض الفوسفوريك وبما يعادل : مادة الفوسفوجبسم -ا .و يتم خزن تلك المواد في احواض خاصة فيها زن فــي احــواض خاصــة بهــا وبعــد ان تجفــف تتــرك كــاكوام علــى جوانــب تلــك وهــي ايضــا تخــ: اطيــان قاعديــة -ب .األحواض :وتشمل الملوثات السائلة -٢ .مياه قاعدية تحول الى وحدة معالجة النفايات الصناعية -ا ويتم ترسيب تلك المخلفـات ثـم تنقـل بعـد المعادلـة الـى . مياه حامضية تحول ايضا لوحدة المعالجة الصناعية -ب ).٥ جدول(اخرى وفق المواصفات المسموح بها احواض .حامض الفلوسيليسيك وهو ناتج عرضي يعاد استخدامه مره اخرى -ج ,٧fao1985 جـدول ( لتقييم المياه المصرفة من خالل االطالع على القيم المسموح بها عالميـا landon1984, ي غيــر مقبولــة كميــاه هــ)٦جــدول (نالحــظ ان مواصــفات الميــاه المصــرفة ) ١٩٨٨ومحمــود للشرب وكذلك هي ضارة عند استعمالها لري النباتات او تصريفها الى االراضي المجاورة النهـا سـتزيد مـن ملوحـة اســـتنادا الـــى منظمـــة الصـــحة .التربـــة وبالتـــالي تـــدمير صـــفات التربـــة البيلوجيـــة والكيمياويـــة والفيزياويـــة والهندســـية بينمـا التركيـز المقبـول للكبريتـات فـي ميـاه ٩.٢-٦.٥ان يتـراوح بـين يجـب phفـان ) ١٩٨٨ محمـود( العالميـه امـا الفلوريـدات فـان التركيـز المسـموح بـه يتـراوح . لتـر/ملغـم ٤٠٠لتـر ويجـب ان ال يتعـدى /ملغم ٢٠٠الشرب هو ا لتر ممـا يسـتوجب ازالـة قسـم منـه علمـ/ملغم ٤لتر وفي بعض المصادرالمائية يتجاوز /ملغم ١.٥-١بين اقل من يـؤدي الـى ) يـوم / ملغم ٦اكثر من (ان عدم وجوده بالمياه يؤدي الى تسوس االسنان وان تناوله في مياه الشرب يـوم فسـيؤدي الـى /ملغـم ٢٠اما اذا زاد تناولـه عـن .ضعف نمو االسنان عند االطفال وظهور بعض البقع عليها ات فهنــاك الزال جــدال علميــا حــول ايهمــا أمــا الفوســف). ١٩٩٧ wardlaw (اضــطراب المعــدة واالم فــي العظــام اكثــر خطراعلــى البيئــة هــي ام النتريــت ولكــن تــم االتفــاق علــى انهمــا يســهمان فــي تلــوث البيئــة مــن خــالل ظــاهرة فـي جسـم االنسـان يـؤدي ان زيـادة امتصـاص الفسـفور علـى حسـاب الكالسـيوم). ١٩٨٨محمـود ( االثراء الغـذائي waldraw( كبــار الســن واالشــخاص المصــابون بــبعض امــراض الكلــى الــى نخــر العظــام خاصــة عنــد النســاء ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٤ كما ان زيادة كمية الكبريتات فـي الميـاه المصـرفة وتجمعهـا فـي التربـة سـيزيد مـن تركيـز االمـالح ويغيـر ). ١٩٩٧ للمنشــات تحــت االرضــية مــن اســس ) soil corrosive(ســتزيد مــن تاكــل التربــة دالــة الحامضــية فيهــا وبالتــالي .)١٩٩٧ droste(ية وانابيب وغيرها كونكريت الملوثات الغازية -٣ تنطلق الملوثات الغازية عن طريـق حـرق الكبريـت فـي وحـدة حـامض الكبريتيـك وينـتج عنـه غـازي ثـاني وثالـث كانت تلك الغازات تحجز بواسطة مرشـحات اي فالتـر خاصـة ولعـدم توفرهـا ١٩٩١وقبل حرب .اوكسيد الكبريت .في المنطقة شكلة بيئية واضحهجعل من تدفقها م معالجات التلوث في الشركة :ثانيا بالنســبة للملوثــات الصــلبة مــن مــادة الفوسفوجبســم فقــد جــرب اســتخدامها بالتعــاون مــع امانــة بغــداد كمــادة كمـــا قامـــت بعـــض الدراســـات . مـــع االســـفلت اال ان التجربـــة فشـــلت بســـبب ارتفـــاع التكـــاليف% ٣٠تبلـــيط وبنســـبة اتصـال ( من قبل طالب الـدكتوراه زيـدون عبـد الكـريم احمـد ١٩٨٨جامعة بغداد عام / مع كلية الزراعة بالتعاون وهنــاك . السـتخدامها فــي زيـادة انتــاج الـذرة الصـفراء وقــد نجحـت التجربــة لكنهـا لالسـف لــم تعمـم )١٩٩٠شخصـي الجبـوري (ث الزراعيـة ابحـلال ءبـادراسات جارية الستخدامها في تحسين بعض صفات التربة الزراعية مع مركز ا بشــكل واســع فــي المنــاطق المطريــة شــديدة الغســل علمــا ان تلــك المــادة ثبــت علميــا نجاحهــا واســتخدامها). ٢٠٠٠ وكذلك في انتاج السمنت بعـد خلطـه مـع السـجيل الزيتـي ) ١٩٨٠واخرون troeh( ة لمعالجة الترب الحامضي .بحثا تم التطرق اليه في مقدمة الفي تركيا كم يتواجــد الكــادميوم بالصــخور الفوســفاتية اساســا وتنتقــل كميــات مهمــة منــه مــع االســمدة الفوســفاتية اذا مــاتم تنقيتهــا لترهــوغير /ملغــم ٠.٠٥يعتبــر الكــادميوم مــن العناصــر الســامة للنبــات وان وجــوده بمــاء الشــرب بــاكثر مــن . منــه استخدام الماء لكـن هنـاك حـاالت تسـمم بـه عـن مسموح على الرغم من عدم مالحظة حاالت تسمم به عن طريق ).١٩٨٨محمـود (طريق التنفس وعن طريق الغذاء وعلى عكس الزئبق فـان جميـع امـالح الكـادميوم تعتبـر سـامة الـى عـدم تصـريف الميـاه المعادلـة الـى ١٩٩٢-١٩٨٨بالنسبة للملوثات السائلة فقد حاولت الشركة في الفتـرة اام جــدول ( باالعتمــاد علــى التبخيــر اال ان الظــروف الجويــة لــم تســاعد فــي انجــاح التجربــة النهــر بــل اعــادة تــدويرها و فــي العــام .، وقــام قســم االبحــاث فــي الشــركة بدراســة امكانيــة اســتخدام المخلفــات الســائلة فــي ري النباتــات)٥ ا للتجارب الزراعيـة توقف تصريف المياه المعادله الى النهر وبقيت المياه في احواض خاصة الستخدامه ١٩٩٩ مشكلة الملوثات الغازية فقد بقيت بدون عالج لتوقف مرشحات المداخن في وحدة انتاج إما .وفى عمليات التبريد الحـرب طالـت مــابين أضــرارعلمـا بـان . الكبريـت عـن العمـل وعــدم امكانيـة اسـتبدالها بسـبب الحصــار االقتصـادي ج ولالسـف ماعـدا مرشـحات وحـدة انتـاج الكبريـت المهمـة بيئيـا من الشركة وتم اعادتها الـى االنتـا% ٩٠ -٧٠ طـن فلورسـيلك واحتراقهـا ١٨٠االف طن من الحـوامض و ٥الى تسرب ١٩٩١حرب الكويت عام أدتلقد . تلك كــم باالضــافة الــى ٢٠وغطــى منطقــة قطرهــا so2 طــن كبريــت ســائل وتحولــه الــى غــاز ٥٣٦٠٠وكـذلك احتــراق يعتبــر ثــاني اوكســيد الكبريــت مهـيج لالنســجة فــي االنــف والفــم والعــين . كبريــت صـلبالــف طــن امونيــا و ١٨حـرق ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٥ عــادت الشــركة مــرة اخــرى بــالتركيز ١٩٩٤وبعــد عــام ). ١٩٨٨محمــود ( ويســبب استنشــاقه الــى التهــاب الــرئتين نظــرا علــى وحــدات المعالجــة للعــودة بهــا الــى ســابق عهــدها ولكنهــا لــم ترتقــي لالســف الــى المســتويات التصــميمية .لتقادمها االستنتاجات والتوصيات -٤ على الغذاء قد زاد من وتيرة صناعة واستهالك مختلف االسمدة الكيمياوية مما يزيد من زيادة الطلب إن -١ ان زيادة التصنيع وفضالته وسوء ادارة المعالجة .الناتج من هذه الصناعة خطر التلوث العالمي اوية يؤثر سلبا على عناصر البيئة المتمثلة بالتربة والماء والهواء اذا ما والتداول واستخدام االسمدة الكيم إدارةوتداولها واستخدامها األسمدةتتطلب صناعة . تم وفق الضوابط والتشريعات البيئية المقره عالميا .عالية الدقة لكي نضمن عدم العبث بالبيئة من خالل توفير احدث االجهزة والخبرة العالمية صادر الطاقة تعتبر من اهم ملوثات البيئة لذا يجب العمل على تخفيض الطاقة المستخدمة في لكون م -٢ وقد بينت . انتاج االسمدة الكيمياوية من خالل تحسين كفاءة التقنيات المستخدمة واستخدام تقنيات حديثة .امستهلكة في صناعة االسمدة عالميالدراسات انه باالمكان توفير حوالي ثلث الطاقة ال في العراق، وخاصة بعد حرب الكويت، كان هناك تدمير كبير لمجمل البنى التحتية وخاصة بما يتعلق -٣ وبالتالي اثر سلبا على وكذلك احتراق االف االطنان من الحوامض والكبريت بصناعة االسمدة الكيمياوية لى حساب نوعية الغذاء اما بعد فرض الحصار فقد زادت وتيرة التصنيع واالستهالك ع. البيئي الجانب :يمكن تقييم االثر البيئي لصناعة واستخدام االسمدة الكيمياوية في العراق كاآلتي. وكذلك التلوث البيئي ان هناك سوء استعمال لالسمدة الكيمياوية كنتيجة لوفرتها اوال وقلة الوعي عند الفالح العراقي أ .ائر الزراعية والبيئية والري وغيرهاالدوائر المعنية بالموضوع كالدو عدم اكتراثوكذلك من خالل متابعة بعض االحصائيات المتعلقة بالموضوع وخاصة تلك المتعلقة بالهدر وبتلوث ب المياه تظهران تراكيز بعض العناصر السمادية عالي جدا او تفوق ما مسموح به احيانا وخاصة بما لكميات كبيرة من وبالتالي خسارتنايتعلق بمياه المصب العام التي تصب في الخليج العربي . لعناصر السماديةا ماعدا التراكيزالعالية للملوثات السمادية في مياه المصب العام لكن يمكن القول ان مشكلة التلوث ت باالسمدة كنتيجة للتصنيع او االستخدام هى ضمن الحدود المسموح بها على المدى القريب لكنها .مهددة بالخطرفي المستقبل التالي ستكون صحة االنسان ستتراكم في عناصر البيئة وب تطرح الشركة العامة للفوسفات ملوثات سائلة بانواع مختلفة تتناسب طرديا مع حجم االنتاج ث وبكميات اليستهان بها كالمياه الصناعية التي يتم معادلتها كيماويا ومعالجتها في وحدة المعالجة رغم فوسفوجبسم التي تخزن في احواض خاصة خارج المعملبالشركة وكذلك ملوثات صلبة كال ان وحدات المعالجة في الشركة .ثبوت امكانية استخدامها في المجال الزراعي وفي انتاج السمنت ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٦ العامة للفوسفات ال يمكنها القيام بعملية التنقية كما ينبغي وبالتالي زيادة المطروحات والمخلفات الشركة العامة للفوسفات بنفس سياسة االنتاج الحالية فستتفاقم مشكلة اذا استمرت .الملوثة للبيئة التلوث البيئي اال اذا تم اصالح وحدات المعالجة التى دمرتها الحرب واالرتقاء بنوعية المواد االولية .الداخلة في االنتاج تباع التشريعات على المعنيين بصناعة االسمدة الكيمياوية من القطاعين العام والمختلط والخاص ا ج وبما ال تؤثر على الموارد البيئية من خالل متابعة وصيانة وحدات المعالجة والنقل والخزن وكذلك التوزيع وبما ال يتعارض مع تعليمات السالمة المهنية والصحة العامة وحماية البيئة العراقية الصادر .من وزارة الصحة راقبة والتفتيش والتنفيذ الصارم للقوانين التي تحمي على دوائر الصحة والبيئة تشديد اجراءات الم ح .الصحة والبيئة من مخاطر تصنيع وتداول واستعمال االسمدة الكيمياوية :األجنبيةالمصادر 1. akmre, ardeniz karagoz mineral research and expolaration (2003) low energy cement clinker from phosphogypsum and oil shale. ankra university. 2. avery, d. (1997) environmentally sustaining agriculture. the hudson institute, pub. choices, aaea. 3. droste, ronald l. (1997) theory and practice of wastewater treatment. wiley & sons, inc. ny. 4. efma, european fertilizer manufacturing association (2005) production processes: www.efma.org. 5. fao (1985) irrigation and drainage – water quality. bulletin no 2. 6. ifa, international fertilizer industry association (1998) the fertilizer industry, world food supplies & the environment unep. 7. ifa, international fertilizer industry association (2005) fertilizer indicator – raw material reserves: www.fertilizer.org/ifa. 8. isherwood, k.h (1998) mineral fertilizer use & the environment, international fertilizer industry association. published in association with unep. 9. kong shang, g. (1998) energy consumption and greenhouse gas emission in fertilizer production. ifa technical conference. moracoo. 10. landon, j. r. (1984) booker tropical soil manual. pitman press, great britain. 11. mayrhofer, h. (1983) world reserves of minable potash salts, the salt institute, alexandria, va, usa. 12. mclaren and skinner (1987) industrial minerals and world development pub. j. wily & son, ny. 13. mutter, g. m (1989) water erosion of calcareous soils in southeast of england. unpublished ph. d thesis, university of london. 14. syres, j. k. (1997) soil and plant potassium in agriculture. the fertilizer society. proceeding no.411, april 1998. york, u.k. 15. troeh et.al (1980) soil and water conservation for productivity and environmental protection. prentice-hall, new jersey, usa. ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٧ 16. waldraw, g. m. (1997) contemporary nutrition. mcgraw-hill, n.y. .الجامعة العربية . التقرير االحصائي السنوي) ٢٠٠٣( لألسمدةاالتحاد العربي -١٧ تحسين كفاءة الطاقة في الصناعات الكثيفة الستهالك ) ٢٠٠٥( أالسكوا، اللجنة االقتصادية واالجتماعية لغربي اسيا-١٨ .المتحدة األمم. الطاقة .جامعة بغداد. اطروحة دكتوراه .القياس االقتصادي لكلف التلوث البيئي الصناعي )٢٠٠٠( عطية اقبال الجبوري،-١٩ .نشر، وزارة التعليم العالي والبحث العلمياساسيات علم التربة، دار التقني للطباعة وال) 1984(عبد الفتاح العاني،-٢٠ .سلسلة المعارف البيئية، الدار العربية للنشر، مصر النفايات الخطرة،) ٢٠٠٠( عبد الجواد، احمد -٢١ كلية /مجلة الهندسة والتنمية . االثر البيئي لالسمدة الكيمياوية على الموارد المائية العراقية) ٢٠٠٣(غازي مالح مطر،-٢٢ .العراق. الجامعة المستنصرية/ دسة الهن وزارة التعليم العالي والبحث العلمي/ جامعة الموصل . علم وتكنولجيا البيئة) ١٩٨٨(طارق احمد محمود،-٢٣ .والحياة، وزارة البيئة العراقية تلوث المصادر المائية بالنتروجين، مجلة البيئة) ٢٠٠٧(محمد احمد نجم الدين،-٢٤ ٢٠٠٣سط ومجموع الطاقة المستهلكة في صناعة األسمدة عالميا لعام متو ): ١(جدول )٢٠٠٥االسكوا ( العنصر الغذائي المنتج االستهالك العالمي لألسمدة )مليون طن( متوسط االستهالك للطاقة )طن/جول جيغا( إجمالي الطاقة المستهلكة صناعة األسمدة في )مليون جيغا جول( المتوسط العالمي دث التقنياتاح اإلجمالي العالمي احدث التقنيات النيتروجين p2o5الفسفور k2oالبوتاسيوم ١١٠ ٣٥ ٢٣ ٤٩ ٥ ٩ ٣٦ ٩ ٤ ٥٤١٢ ١٩٣ ٢١٤ ٣٩٢٧ ٣٢٢ ٨٥ ٣٦٩٠ ٥٨١٩ ١٦٨ المجموع تراكيز بعض العناصر الثقيلة والنادرة في األسمدة المصنعة المختلفة) ٢(جدول ) ٢٠٠٠عبدالجواد ( األسمدة الفوسفاتية )ppm(نصرالع األسمدة النتروجينية األسمدة العضوية األسمدة المصنعة من المخلفات ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٨ زرنيخ كادميوم كوبلت كروم نحاس زئبق رصاص قصدير ١٠٠٢ ١٧٠-٠.١ ١٢١ ٢٤٥-٦٦ ٣٠٠١ ١.٢٠.٠١ ٢٢٥٧ ١٤٥٠-٥٠ ١٢٠-٢.٣ ٨.٥٠.٠٥ ١٢-٥.٤ ١٩-٣.١ ٢.٩-٠.٣ ٢٧٢ ١.٤٢ ٢٥٣ ٠.٨-٠.١ ٢٤-٠.٣ ٠.٣٦٠.٠١ ١٧٢٢ ٠.٤٠.٠١ ٢٧-١.١ ٥٦٦-١٥ ٥٢٢ ١٠٠٠.٠١ ٢١٠.٠٩ ٣٥٨٠-١٣ ٢١-٠.١ ٢٢٤٠-١.٣ ٥٨٩٤-٨٢ في مياه دجلة والفرات للمحافظات الفسفورالمضافة وتركيز األسمدةالمساحات الزراعية وكميات ):٣(جدول ) .٢٠٠٣مطر ( 2000العراقية لعام المحافظة )دونم(روعةالمساحة المز محاصيل بساتين األسمدةاستهالك )طن( السماد المضاف )دونم/كغم( في الفسفورتركيز )لتر/ملغم(المياه نهر دجلة نينوى تأميم صالح الدين ديالى بغداد واسط ميسان 2976000 955541 680000 363319 783.731 949436 387884 400 1918 11116 120000 162608 62000 10910 45835 55304 32.900 15842 27177 49050 29707 15.4 57.8 47.6 32.8 28.8 48.5 74.5 0.060 0.160 0.257 0.268 نهر الفرات انبار بابل كربالء نجف قادسية مثنى ذي قار 530000 409088 150000 285264 136493 134000 250000 12500 113403 91000 30000 44138 13000 23000 21697 29970 7561 24249 12566 7557 23750 40.0 57.3 31.4 76.9 69.6 51.4 86.9 0.153 0.165 شط العرب البصرة )عدا النخيل( 172071 7500 12891 52.2 0.306 ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢٠٩ 0.128:معدل 40.0:معدل 396056 770993 9162828 المجموع ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢١٠ .)٢٠٠٣مطر (بعض الصفات العامة للمياه في محافظة ذي قار): ٤(جدول نوعية المياه المصب العام مياه اآلبار مياه االهوار الصفة ووحدة القياس ph ec )سم/ملموز( sar ٧.٧ ٥.٣ ٦.١ ٧.٤ ١١.٥ ١٥.١ ٧.٥ ١٧.٨ ٧٦.١ )meq/l(ايونات موجبة ca mg na k ٢٢ ٨ ٢٣ ٠.٤٦ ٣٢ ١٤ ٧١ ١.٥ ٤٤ ١٢٧ ٧٠٠ ١٠.٥ )meq/l(ايونات سالبة so4 cl hco3 no3 )ppm( p )ppm( ٣٠ ٢٩ ١.٨ ٤.٦٣ 0.08 54 63 2 111.8 0.11 30 742 3.2 108.8 6.05 .على التوالي ) ppm( لتر/ملغم ٣و ٥٠يعتبر تركيز النترات والفسفور خارج الحدود المسموح بها إذا تجاوز : مالحظة ) 2000الجبوري ( اإلنتاجية مستلة من سجالت الشركةالملوثات الناتجة عن العمليات ) ٥( جدول السنوات سفوجبسمالف )سنه/طن( المياه المصرفة والمعادلة الى النهر من وحدة المعالجة )مليون متر مكعب( ٠.١٩٤٠٠٠ ١٣٦٤٠٠٠ ١٩٨٨ ١٢٩٠٠٠٠ ١٩٨٩ * ١٠٥٠٠٠٠ ١٩٩٠ * ٦٩٠٠٠ ١٩٩١ * ٤٠٣٠٠٠ ١٩٩٢ * ٠.١٦٣٠٠٠ ٥٠٣٠٠٠ ١٩٩٣ ٠.٧٠٠٠٠٠ ٣٤٨٠٠٠ ١٩٩٤ 1996 ٠.٤٣١٠٠٠ ٢٦٩٠٠٠ 1998 ٢.٩٤٦٠٠٠ ١٨١٠٠٠ 2000 ٢.٥١٥٠٠٠ ١٩٥٠٠٠ 2002 ٠.٦٩٢٠٠٠ ٩١٠٠٠ .المعاملاستخدامها وتدويرها ضمن عمليات إعادةلمحاولة خاصة أحواضتوقف تصريف المياه الى النهر و كانت تخزن في ١٩٩٢الى ١٩٨٩من عام * ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢١١ الجبوري ( حسب التوجيهات المعمول بها في الشركةالصناعية المصرفة المياهنسب الملوثات في ) ٦(جدول 2000( الرمز نوع الملوثات المسموح بها تراكيزال للتصريف في الشركة ٩.٤ ph تركيز الهيدروجين لتر/ ملغم ٥اقل من p2o5 خامس اوكسيد الفسفور لتر/ م ملغ ٥ f فلوريد لتر/ ملغم ٧٥٠ so4 كبريتات وما مسموح به عالميا) ppm( التراكيز الطبيعية) ٧( جدول )من اعداد الباحث( لبعض العناصر النادرة في المياه والتربة التربة الماء العنصر الري الشرب المسموح به المتوسط المدى الحيوان اإلنسان كادميوم كبريت قصدير اسنح نيكل رصاص فلور 0.01 ٤٠٠ ١ ٠.٠٥ ١.٥ ٠.٠٥ ٢ ٠.٢ ٠.١ ٢ ٠.٠١ ٢ ٠.٢ ٠.٢ ٥ ٢٠.٠١ ١٦٠٠-٣٠ ٩٠٠١ ٢٥٠٢ ٧٥٠٢ ٣٠٠٢ ٠.٣٥ ٧٠٠ ٩٠ ٣٠ ٥٠ ٣٥ ٣ ٣٠٠ ١٤٠ ٧٥ ٣٠٠ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ٢١٢ موديmت عندما (h3=2 m) and ( ∆∆∆∆ h=3, 4 and 8m) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� effect of freezing and thawing on stress-strain relationships of polymer modified concrete (pmc) abstract the investigation includes the effect of freezing and thawing cycles on stress-strain relationships of polymer modified concrete (pmc). cycles of freezing and thawing contains 12 hours at 100°c and 12 hours at -4°c. the process of cycles of freezing and thawing simple experimental technique is used to obtain the complete stress-strain curves up to strain of 0.006 (both ascending and descending portions) sample subjected to freezing and thawing cycles (ftc), then subjected also to stress-strain tests. keyword : polymer modified concrete, compressive strength, modulus of elasticity, styrene butadiene rubber, foil gages. ������� � �� � ��– ������ ���� ��� ������� –������� �������� � � ��� ���! "�� �##$�"�� ������ � � � � �������� ���� �� ����� ����� ����� � ��� – ��������� ������� �!�" � #�$% ��. ��'�� �� ����� �� ��(�� ��������)* ��� ��! ���� �)),, ( � ��.� ���)* ����' ���� ��! )/0 ( '��.� '��� . ����� ���� ���!� �������� ���� ��)1, ( 23� � � #�4 � � �� #���� 5��"�!� 5� 67��� �� 8���� 5�� ��'���� – #�'$% �� ��(��)#9� ��� ���4�� :9��� .( 5� �������� ���� �� ������ �$�";< 7��� �� = >������ –#�$% �� . nomenclature ft : splitting tensile strength (n/mm 2 ) fc : compressive strength (n/mm 2 ) p : the applied load of machine (n) l : height of cylinder specimens (mm) es : modulus of elasticity of steel (n/mm 2 ) dr. ameer gh. taleb al-kufa university civil eng. dept. mohammed h. salih al-kufa university civil eng. dept. �.6��� 6��@ a"< �b:*� ��"�1–����3 ���4 ����$ ����3 (&c � 1 ��de � % �fc �b:*� ��"�1–����3 ���4 ����$ ����3 (&c g�� +�:h �di �b:*� ��"�1–����3 ���4 ����$ ����3 (&c qusay abdulhameed jabal al-kufa university civil eng. dept. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� fs : stress in steel tube (n/mm 2 ) pconc : the load on concrete specimens (n) ac : cross sectional area of concrete cylinder (mm 2 ) ptotal : total load by machine (n) εs : average strain in steel tube (mm/mm) σc : stress in concrete specimens (n/mm2) ps : the load on steel tube (n) specimens and materials specimens were (7.5 × 15 cm)cylinders, 36 specimen were made to obtain total stress-strain curves, a different mix proportions of cement: fine aggregates: coarse aggregates of (1:1.5:2) (1:1.5:3) and (1:1.5:4) using styrene butadiene rubber (sbr) as a percentage of cement weight of 15% to improve the properties of ordinary concrete and makes the concrete with high strength values. the maximum size aggregate is (10 mm) of 2.8 specific gravity sieve analysis is shown in (table 1) ordinary portland cement was used in all mixes ordinary drinking water was used in all mixes. curing : ordinary mixes were cured in water, but polymer mixes cured 6 days in water and 22 days in air. this gives the perfect curing according to radomir investigation (radomir, 1998) experimental program testing method a simple technique was developed by astm c-469 (astm, c-469, 1981) to obtain the stress-strain curve of concrete ( both ascending and descending portions ) up to the strain of 0.006 (figure 1) (wang, 1978) concrete cylinders were loaded in parallel with a steel tube. the high strength steel tube was case hardened so that it's stress-strain curve was linearly elastic up to the strain of 0.006. the specimens were capped in the testing machine to ensure that the load will be shared simultaneously by both the tube and concrete cylinder immediately on loading. the strains in the steel tube were measured with two foil-type resistance strain gauges . these strains gave not only the amount of load taken by the steel tube, but were also used to obtain nominal strains in concrete. thus knowing the total load and steel strain, the stress – strain relationship of each curve were made by three tested specimens and taking average of three readings of stress. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� calculations simple calculations to obtain the stress-strain curve are given below the strain in steel tube multiply by the modulus of elasticity of steel (es) gives the stress in steel tube: єs * es = fs ...(1) where єs : the strain (avg. strain in steel by two foil gages) es : the modulus of elasticity of steel 207000 mpa fs : the stress in steel tube 1. the load on concrete pconc =ptotal -ps ...(2) where pconc : the load on concrete specimen ptotal : total load by machine ps : the load on steel tube ps =fs x as ...(3) as : area loaded (steel tube) 2. the stress in concrete (σc) is calculated from eq.4 below c conc c a p =σ ...(4) where σc : the stress in concrete ac : area ( loaded) by concrete ac = 2 )75( 4 π (in mm 2 ) thus, executing the calculations above gives the total stress – strain relationship of concrete. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� analysis of results figures (2-7) show the effect of cycles of freezing and thawing on stress – strain relationships for different mixes of concrete with or without polymers , the mixes with 15% p/c shows the higher values of maximum compressive strength with respect to the reference mix after ftc (ohama, 2003) figure (2) shows the effect of ftc on stress-strain relationship of concrete mix (1:2:4) with 0% p/c ( reference mix) . the reduction in max. compressive strength of the reference mix due to ftc is about (66%), but with using sbr polymer, the reduction is very little see (figure 3 ) and its about (2.2%) . table 3 shows the reduction in the value of the chord modulus of elasticity for the mixes. the reduction after ftc cycles is about 68% for (1:2:4) mix, but after using sbr polymer , the reduction is very less and about (9.8%). figure 4 also shows the effect of ftc on stress-strain relationship of concrete with mix proportions of (1:1.5:3) without adding polymers , the reduction in compressive strength is about (47%), but after using polymers, the reduction after ftc is about (1.2%), (see fig. 5 ). the reduction in modulus of elasticity for the reference mix with mix prop. of (1:1.5:3), is about 57.7 , but the reduction in mixes with p/c=15% is about 0.4% and this is perfect, see (table 3). figure 6 shows the effect of ftc on (1:1.5:2) mixes (p/c=0%) , the reduction in compressive strength is about (48.2 %). with using 15% p/c , the reduction is a bout (4.2%) see (figure 7). the reduction in modulus of elasticity for (1:1.5:2) reference mix is about ( 57.7 ), while in 15% p/c mix , is about (3.8%) see (table 3 ) discussion the improvement in properties of concrete with adding styrene butadiene rubber seen in previous figures (2-7), is very excellent, because of the action of styrene butadiene rubber (watanable, 2005) polymer latex modification of concrete is governed by both cement hydration and polymer film formation processes (wang, 1978), some chemical reactions may take place between the surface of polymer particles and calcium ions ( ca +2 ) , ca(oh)2 solid surfaces , or silicate surfaces over the aggregates (kaempfer, 2006, ye, 2005) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� moreover, there are other reasons that cause this improvement in the properties of these mixes ; the first is that the voids in the reference mixes are filled up by polymer particles when using the polymer with 15% , (p/c=15%) , also , it appears that the microcracks in latex modified mortar and concrete under stress are bridged by the polymer films or membranes formed , which can prevent cracks propagation , and that a simultaneously strong cement hydrateaggregate bond is developed (ohama, 1998) therefore, these reasons cause the prefect reduction in compressive strength and modulus of elasticity after ftc conclusion 1. the action of ftc on concrete with different mix proportions without using polymer is very high with respect to polymer modified concrete (pmc) . 2. (pmc) with 15% p/c gives perfect results in both compressive strength and static modulus of elasticity . 3. pmc gives a perfect durability against cycles of freezing and thawing, because of the action of polymer – film formation and less voids inside the concrete. references 1radomir, j. and vlastimir, s., " experimental research on polymer modified concrete ". aci materials journal, july-august 1998:463-469. 2astm committee, c-469 " standard test method for static modulus of elasticity and poisson's ratio of concrete in compression". 1981. 3wang, p.t., shah, s.p., and naaman, " stress-strain curves of normal and lightweight concretes in compression". journal of the american concrete institute, no. 75-62, 1978: 603-611> 4ohama, y., " study on properties and mix proportioning of polymer-modified mortars for buildings". report of the building research institute, no. 65 (2003) 100-104. 5watanabe, t., and kawano, t., " study on sbr latex composite material ". mrs international meeting on advanced materials, vol. 13 advanced cement and chemically bonded materials. mrs, pittsburgh, 2005, pp 6kaempfer ,w., durability of polymer-modified mortar and concrete. journal of structural and construction engineering (in japanese), architectural institute of japan , 664 (2006)26. 7ye, z. , research on the structure of reactive polymer cement materials .technological institute of the royal flemish society of engineers, antwerp , 2005,p.p.457-462. 8ohama, y., "polymerbased admixture", cement and concrete compositions, 1998, 20:189212. al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� table 1: sieve analysis of aggregates i.s. sieve designation % passing by weight indian standard (i.s.) for grading zone ii 10 mm 100 100 4.75 mm 93 90-100 2.36 mm 85 85-100 1.18 mm 77 75-100 600 micron 62 60-79 300 micron 20 12-40 150 micron 1.0 0-10 table 2: chemical composition of styrene butadiene rubber (sbr) infra-red (i.r) test ph humidity content solid particle content % styrene butadiene rubber with small percentage of admixtures 8.2 42.4 57.42 table 3: the reduction in elastic modulus of elasticity due to ftc reduction in elastic modulus due to ftc% chord modulus of elasticity after ftc (gpa) chord modulus of elasticity before ftc(gpa) % p/c w/c mix. proportion 9.8 42.4 47.0 15 0.35 1:2:4 68 7.8 24.4 0 0.4 1:2:4 0.4 67.5 67.8 15 0.35 1:1.5:3 57 12.6 29.3 0 0.4 1:1.5:3 3.8 68.6 71.3 15 0.35 1:1.5:2 57.7 15.7 37.1 0 0.4 1:1.5:2 al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 �� figure (2) the effect of ftc on stress-strain behaviour for ordinary concrete (without polymers) with (1:2:4) mix proportion mix. proportion 0% p/c ref. mix. w/c=0.4 0 5 10 15 20 25 30 35 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 axial strain x10 (mm/mm) c o m p re s s iv e s tr e s s ( m p a ) before ftc (fc=31.8 mpa) afte re ftc (fc=10.9 mpa) mix. proportion 1:2:4 p/c=0% ref. mix. w/c=0.4 figure1test set up high strength steel tube 2 foil strain gauges machine head machine base capping 15 cm concrete specimen φ=9.3 cm 7.5 cm steel plate mpa ) mpa ) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (3) the effect of ftc on stress-strain behaviour for pmc with mix proportion of (1:2:4). figure (4) the effect of ftc on stress-strain behaviour for (1:1.5:3) mixes without polymers mix proportion 1:2:4 p/c=15% w/c=0.35 0 10 20 30 40 50 60 70 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 axial strain (mm/mm) c o m p re s s iv e s tr e s s ( m p a ) before ftc (fc=60.1 mpa) after ftc (fc=58.8 mpa) mix proportion 1:1.5:3 p/c 0% w/c=0.4 0 5 10 15 20 25 30 35 40 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 axial strain (mm/mm) c o m p re s s iv e s tr e s s ( m p a ) before ftc (fc=37.9 mpa) afte r ftc (fc=20.1 mpa) mpa) mpa) mpa) mpa) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (5) the effect of ftc on stress-strain behaviour for pmc of (1:1.5:3) mixes. figure (6) the effect of ftc on stress-strain behaviour for (1:1.5:2) mixes without polymers mix proportion 1:1.5:3 p/c=15% w/c=0.35 0 10 20 30 40 50 60 70 80 90 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 axial strain (mm/mm) c o m p re s s iv e s tr e s s ( m p a ) be fore ftc (fc=80.8 mpa) after ftc (fc=80.8 mpa)79.8 mix proportion 1:1.5:2 p/c=0% w/c=0.4 0 5 10 15 20 25 30 35 40 45 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 axial strain (mm/mm) c o m p re s s iv e s tr e s s ( m p a ) be fore ftc (fc=41.1 mpa) afte r ftc (fc=21.3 mpa) mpa) mpa) mpa) mpa) al-qadisiya journal for engineering sciences vol. 2 no. 3 year 2009 ��� figure (7) the effect of ftc on stress-strain behaviour for pmc of (1:1.5:2) mixes. mix proportion 1:1.5:2 p/c=15% w/c=0.35 0 10 20 30 40 50 60 70 80 90 100 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 axial strain (mm/mm) c o m p re s s iv e s tr e s s ( m p a ) be fore ftc (fc=85.9 mpa) after ftc (fc=82.3 mpa)mpa) mpa)